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House Republicans praised Speaker John Boehner (R-Ohio) and the deal he cut to avoid a national default during a rare Sunday night conference call, giving first-blush approval to a plan that must still be committed to legislation and passed by both chambers of Congress.
Now comes the hard part for the four heads of congressional caucuses: Selling the fine print.
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reset Boehner touts debt deal Bachmann vows to vote 'no' Obama announces debt deal POLITICO 44
That’s the job that Boehner, House Minority Leader Nancy Pelosi (D-Calif.), Senate Majority Leader Harry Reid (D-Nev.) and Senate Minority Leader Mitch McConnell (R-Ky.) signed up for when each gave his or her word to President Barack Obama Sunday night that the deal was in hand.
It’s complicated, multi-dimensional and full of peril for the priorities of each side — so much so that while the White House pointed to the possibility of the Bush tax cuts expiring, House Republican leaders were telling their rank and file that the deal made that scenario less likely.
It’s not “the greatest deal in the world,” Boehner told his troops.
“But it shows how much we’ve changed the terms of the debate in this town,” Boehner said on the call, according to a transcript released by the speaker’s office. “There is nothing in this framework that violates our principles. It’s all spending cuts.”
Come Monday, all eyes will be on House Republicans because they seldom jump in line without a fight.
Boehner’s lieutenants, including Majority Leader Eric Cantor (R-Va.) and Whip Kevin McCarthy (R-Calif.), applauded the speaker for pushing the president as far as he could while avoiding the economic and political calamity that could result from a default on the nation’s debt — which the Treasury Department has said will happen after Aug. 2 if the cap on the country’s borrowing authority isn’t raised.
House GOP leaders hope to have a bill on the floor on Monday, but no decision has yet been made on which chamber will consider the legislation first.
If the deal holds — and rank-and-file members of both parties in both chambers must still review the particulars — it promises to move Washington out of a crisis mode and into a deficit-reduction mindset. The agreement provides for an increase in the debt ceiling of roughly $900 billion — in two installments — followed by equivalent spending cuts over the next decade. It would also create a “supercommittee” of a dozen lawmakers charged with putting together a deficit-reduction package of $1.2 trillion to $1.5 trillion that can pass Congress. Short of that, automatic cuts of $1.2 trillion to $1.5 trillion, split between domestic and “security” programs, would automatically take effect.
“I think that we have set the tone for the discussion in the year ahead, and I think that’s important,” Rep. Jack Kingston (R-Ga.) told POLITICO Sunday night.
But there will be loud voices of opposition. Rep. Michele Bachmann (R-Minn.), a leading presidential contender, came out against the bill Sunday evening.
The right is not yet revolting. Rep. Allen West (R-Fla.) said he will “wait and get clarification from the” Congressional Budget Office, “however at this time I believe this is a good plan for the American people.”
On the call, Cantor thanked Boehner, saying he did a great job and it was a big win. He also said it was a good deal for conservatives and the decades long fight to get a balanced budget amendment to the constitution passed. Boehner thanked Cantor for conceiving many of the cuts during the talks led by Vice President Joseph R. Biden, the 87-member freshman class and House Budget Chairman Paul Ryan (R-Wis.) for writing his budget. ||||| Negotiators have spent three months mixing and matching potential spending cuts to accompany an increase in the debt ceiling, struggling to find the right combination that would overcome a filibuster in the Senate and to secure a majority in the unpredictable House. The trickiest issue has always been how to create an enforcement mechanism, or a trigger, to compel portions of the deal to be enacted in the future, and over the weekend Senate Minority Leader Mitch McConnell (R-Ky.) engaged in last-minute negotiations with Vice President Biden to produce a trigger that could lead to cuts in entitlement programs and defense spending.
“I would say we are both cautiously optimistic we will reach a conclusion soon,” Senate Majority Leader Harry M. Reid (D-Nev.) said Sunday at noon after speaking with McConnell.
Less than an hour later, however, during a procedural vote, a group of 15 Senate Democrats crowded around one of their leaders, Sen. Charles E. Schumer (D-N.Y.), demanding to know why the framework did not include any increased revenue through tax hikes on the wealthy or the closing of corporate loopholes. The group included the Democratic caucus’s most outspoken liberals, such as Sens. Tom Harkin (Iowa), Barbara A. Mikulski (Md.) and Al Franken (Minn.).
Afterward, Sen. Carl Levin (Mich.), who was part of the huddle, said the group had “mixed” feelings toward the possible deal. “It’s not balanced, it doesn’t have revenues,” he said, disappointed that President Obama’s prior demand for “balance” was not assured. “There are a lot of people who are really withholding judgment.”
Levin said a potential deal-breaker was the trigger — which forces spending cuts across the board if a special committee cannot produce at least $1.2 trillion in cuts that win approval from the Congress. If the potential cuts to Medicare under this trigger include reductions in any benefits to the elderly, Levin said, “then you’re going to lose a lot of Democrats.”
By 5 p.m. Reid had announced his support for the plan and prepared to hold a caucus meeting to describe the package’s details. As long as the frustrations of Levin’s group do not turn into an open rebellion, most senators and top aides believe the Senate will be able to approve the massive legislation, possibly by Monday.
Even members of the Senate’s Tea Party Caucus have signaled that they would require only one 60-vote hurdle to overcome their filibuster efforts and then waive requirements for up to 30 additional hours of debate — a delay that, without acquiescence, would make it impossible to win approval in time for Tuesday’s deadline. | – Not so fast. Is the debt ceiling agreement settled? Or could it still go down in flames? "We all may not be able to support it, or none us may be able to support it," Nancy Pelosi ominously told reporters yesterday ahead of today's Democratic caucus on the plan. The trick now is "selling the fine print"—the deal is "complicated, multi-dimensional and full of peril for the priorities of each side," notes Politico. Defections are expected by both liberals in the Senate and defense hawks in the House. Too many defections could scuttle the plan, notes the Washington Post. Tea Party cover girl Michele Bachmann has already come out against the plan, and liberal Dems are complaining about the plan's lack of tax increases for the wealthy and failure to close corporate loopholes. House Speaker John Boehner is confident he has enough Republican support to pass the legislation even without clear Democratic backing. Though Pelosi earlier pledged her support, Boehner has vowed he's not going to rely on the party. |
blue straggler stars ( bsss ) are brighter and bluer ( hotter ) than the main sequence ( ms ) turnoff ( to ) .
they are located along an extension of the ms in the color - magnitude diagram ( cmd ) of globular clusters ( gcs ) and they are known to be more massive than normal ms stars ( @xcite ) , thus indicating that a process able to increase the initial mass of a single star must be at work . while bsss have been demonstrated to be invaluable probes of gc internal dynamics and their radial distribution is indeed a powerful tool to measure the cluster dynamical age @xcite , many basic questions about the formation mechanisms and the physical properties of these puzzling objects remain open . at the moment
, two main leading scenarios have been proposed for their formation : bsss could be generated by mass - transfer activity in binary systems ( mt - bsss ; @xcite ) , possibly up to the complete coalescence of the two companions , or they may form by collision - induced stellar mergers ( col - bsss ; @xcite ) . + the spectroscopic analysis seems to be the most promising way to discriminate between the two formation channels .
in fact , hydrodynamical simulations predict carbon ( c ) and oxygen ( o ) depletion for mt - bsss , due to the fact that the material on the bss surface comes from the deep regions of the donor star , where the cno - burning already occurred ( @xcite ) .
conversely , very little mixing is expected to occur between the inner cores and the outer envelopes of the colliding stars , so that col - bsss should show normal c and o abundances @xcite .
those theoretical results have been confirmed by the observation in 47 tucanae ( 47 tuc , * ? ? ? * hereafter f06 ) , of 6 ( out of 42 ) bsss showing c and o depletion .
unfortunately , at the moment , 47 tuc is the only gc where such a kind of signature has been oberved .
in fact , the subsequent analysis of the bss population of m4 lead to the conclusion that all of the observed bsss show normal c and o abundances ( * ? ? ?
* hereafter l10 ) , suggesting that either they are all formed through collisions or , more likely , that the depletion is a transient phenomen ( in fact , according to the percentage of co - depleted bsss found in 47 tuc , there should have been 0 - 1 bsss with c and o depletion in m4 ) .
moreover , from the analysis of the bss population in ngc 6397 , @xcite ( hereafter l12 ) highlighted the occurrence of a particle transport process called radiative levitation on the atmosphere of bsss hotter than @xmath0 8000 k. such process , already known to occur in hb stars hotter than @xmath3 k @xcite , alters the surface chemical abundances ( in particular , it increases the mean metallicity ) thus preventing the interpretion of any surface abundance in terms of bss formation mechanism . +
another interesting property that can be studied to infer information on the bss formation processes is the projected rotational velocity v@xmath4 @xmath5 .
however , the theoretical scenario is quite complex .
in fact , mt - bsss are expected to have high rotational velocities because of the angular momentum transfer @xcite .
unfortunately accurate simulations are lacking , mostly because of the difficulty in following the evolution of a hydrodynamic system ( the mass transfer between binary components ) up to the system merge @xcite .
this time - scale is unknown but certainly large , of the order of half a billion years @xcite .
according to some authors @xcite , also col - bsss should rotate fast .
nevertheless , the rotation of both mt and col - bsss might be slowed down by braking mechanisms ( @xcite ) , like magnetic braking and disk locking , for which efficiencies and time - scales are not well known yet . from an observational point of view
, a large fraction of fast rotating bsss ( @xmath0 40% ) has been identified in m4 by l10 but , at the moment , this is the only studied cluster exhibiting such a large population of fast rotating bsss .
in fact , according to f06 and l10 , almost all the bsss in 47 tuc and ncg 6397 have low rotational velocities , with only one exception .
moreover , no difference has been found in the rotational velocity distributions of co - depleted and normal bsss in 47 tuc , suggesting that no particular rotational velocity can be univocally linked to a given formation channel .
+ however , the discovery of two distinct sequences of bsss in the gc m30 ( * ? ? ?
* hereafter f09 ) has recently opened a new perspective in the study of a possible photometric signature of the bss formation process : two almost parallel sequences similarly populated ( 24 stars in the blue sequence and 21 stars in the red one ) have been revealed in this cluster .
the two populations show a different level of segregation ( the red bsss being more centrally concentrated ) and possibly have different origin since the blue sequence is well fit by evolutionary models of col - bsss ( @xcite ) , while the red one well corresponds to the lower envelope of the distribution of mt binaries simulated by @xcite .
f09 suggested that the core collapse event boosted the rate of direct stellar collisions , hardened binary systems and could have generated the two populations 1 - 2 gyr ago .
the present study is devoted to a spectroscopic screening of bsss selected along the two sequences , with the goal of investigating their physical properties and further investigate the proposed interpretation of the two distinct populations .
the paper is organized as follow : the observations are described in sect .
the determination of stellar radial velocities and cluster membership are discussed in sect .
the estimate of atmospheric parameters to all targets is described in sect .
the measured rotational velocities are presented in sect .
[ chem ] describes methods and results of the chemical abundance analysis for our sample .
finally our conclusions are drawn in sect .
[ discuss ] .
this work is based on spectroscopic observations collected with the spectrographs flames and xshooter both mounted at the unit telescope 2 at the vlt of the european southern observatory .
the spectroscopic targets have been selected from a photometric catalog obtained by combining wfpc2@hst data for the central cluster region and megacam ( at the canada - france - hawaii telescope ) data for the outer region ( see f09 for details ) . 1 .
_ flames dataset _ the observations have been performed with the multi - object high - resolution spectrograph flames in the uves+giraffe combined mode , during the nights 7 - 8 - 9 august 2011 . the flames fibres allocation has been made to maximize the number of observed bsss in both the blue and the red sequence .
unfortunately , the majority of the bsss are concentrated in the inner 30 ( f09 ) and some of them have close bright companions . moreover ,
the physical size of the flames magnetic buttons prevents us to simultaneously observe targets that are closer than 11@xmath6 .
we conservatively excluded targets having stellar sources of comparable or brighter luminosity within 3 arcsec .
the flames sample includes 12 bsss , 52 red giant branch ( rgb ) and 49 horizontal branch ( hb ) stars . among the observed bsss
, 4 targets belong to the blue sequence and 8 to the red one .
[ cmdm30 ] shows the cmd of m30 with the selected targets highlighted .
+ two different setups have been used for the spectroscopic observations : hr5a ( with spectral coverage 4340 - 4587 and spectral resolution r@xmath718500 ) and hr18 ( 7468 - 7889 , r=18400 ) , suitable to sample some metallic lines and the o i triplet at @xmath8 , respectively .
exposure times amount to 4.5 hours for the hr5a setup , and to 3 hours for the hr18 .
the spectra pre - reduction has been done by using the latest version of the giraffe eso pipeline , gasgano version 2.4.3 , that includes bias subtraction , flat - field correction , wavelength calibration and one - dimensional spectra extraction . for each exposure we subtracted the corresponding master sky spectrum , obtained by averaging several spectra of sky regions . by combining the sky - subtracted exposures
, we obtained median spectra with signal - to - noise ratios s / n@xmath9 for the selected bsss , and s / n@xmath10 for the rgb and hb stars .
xshooter dataset
_ observations of three bsss belonging to the blue sequence have been secured during the nights 27 and 28 june 2012 with xshooter .
those targets are too faint ( v@xmath018.018.3 ) to be efficiently observed with flames in a reasonable exposure time , but some information can be inferred from xshooter spectra , in spite of the lower resolution of this spectrograph .
the three targets have been observed in stare mode enabling simultaneously the uvb ( @xmath03300 - 5500 ) and the vis ( @xmath05500 - 10000 ) channels .
the slit width was set at 0.8@xmath6 ( r= 6200 ) and 0.7@xmath6 ( r= 11000 ) for the uvb and the vis channels , respectively .
the exposure times range from 45 to 90 minutes , according to the magnitude of the target and the seeing conditions .
the spectral reduction has been performed with the version 2.0.0 of the xshooter eso pipeline @xcite , including bias - subtraction , flat - field correction , wavelenght calibration , correction for sky - background and order - merging .
the spectral extraction has been performed manually with the iraf task _ apall_. in fig .
[ cmdm30 ] the three bsss observed with xshooter are marked with black squares .
in order to assess the cluster membership for each target , we measured the radial velocities ( rvs ) with the iraf task _ fxcor_. synthetic spectra calculated with the atmospheric parameters of the analysed targets ( see sect . [ par ] ) and convolved with a gaussian profile to reproduce the spectral resolution of the observed spectra , have been used as templates for the cross - correlation ( see sect .
[ rot ] for details about the computation of the synthetic spectra ) .
finally , the heliocentric correction has been applied to all the radial velocities . the derived rv distribution is shown in fig . [ vradm30 ] .
the mean radial velocity of the rgb stars is rv@xmath11184.9@xmath120.5 @xmath1 ( @xmath13=3.4 @xmath1 ) which is fully in agreement with that obtained for the hb stars ( rv@xmath11184.6@xmath120.5 @xmath1 , @xmath13=3.3 @xmath1 ) .
the value for the combined rgb+hb star sample is rv@xmath11184.7@xmath120.3 @xmath1 ( @xmath13=3.4 @xmath1 and it is in agreement with previous results by @xcite , @xcite and @xcite .
this value has been assumed as the systemic velocity of m30 and used to infer the cluster membership for each star : stars having rvs within 3@xmath13 with respect to the systemic velocity value have been considered as members of m30 .
the bss rv distribution is in good agreement with that of the rgb+hb stars , with a mean value rv@xmath11184.4@xmath120.7 @xmath1 ( @xmath13=2.7 @xmath1 ) .
all the observed bsss turned out to be cluster members . also , the rvs of the bsss in the two sequences nicely agree with each other : we measured rv@xmath11184.6@xmath121.3 @xmath1 ( @xmath13=3.11 @xmath1 ) for blue bsss and rv@xmath11184.2@xmath120.9 @xmath1 ( @xmath13=2.5 @xmath1 ) for the red ones .
bss # 12005407 deserves a particular discussion .
flames spectra of this star appear featureless and we are not able to derive its rv ( and not to perform the chemical analysis ) .
the observed counts of its spectra are fully compatible with those of the other bsss , thus excluding that the lack of spectral features is due to a wrong centering of the fiber .
this star has been classified as w uma variable by @xcite .
hence , the complete lack of lines in all the observed setups is likely due to a very high rotational velocity ( which is indeed commonly associated to this class of objects ) . in spite of this , on the basis of its central position (
the bss is located at @xmath7 75 from the cluster centre ) , it has been considered a cluster member .
effective temperature ( t@xmath14 ) and surface gravity ( log g ) for all the observed targets have been derived comparing their position in the cmd with theoretical isochrones ( with different ages ) and zero age horizontal branch ( zahb ) models from the pisa evolutionary library @xcite .
given the stellar position in the cmd , each observed target has been orthogonally projected on the closest theoretical model , and t@xmath14 and log g have been derived for each star . for the rgb stars , an isochrone of 12 gyr , z=0.0002 ( compatible with the measured [ fe / h]=@xmath152.3 for the cluster , @xcite ) and @xmath16-enhanced chemical mixture has been superimposed on the cmd of m30 , assuming a distance modulus ( m - m)@xmath17 and e(b - v)=0.03 @xcite .
the same distance modulus and reddening have been applied to a zahb model with the same metallicity and chemical mixture to derive atmospheric parameters for the hb stars . for bsss , isochrones with different ages ( and assuming the same distance modulus and reddening values ) have been used to sample the bss region . the atmospheric parameters for the bss , rgb and hb samples are listed in tables [ bssm30 ] , [ rgbm30 ] and [ hbm30 ] , respectively .
conservative errors in temperatures have been considered : 100 k for bsss and rgb stars and 50 k for hb stars .
errors in gravities are negligible for all targets . concerning microturbulent velocity , the small number of metallic lines ( due to the low metallicity of the cluster ) prevents us to derive spectroscopically this parameter .
microturbulent velocities for the rgb stars have been derived from the relation presented by @xcite , expressing the microturbulent velocity as a function of the surface gravity . for bsss and hb stars
it has been assumed equal to @xmath18 .
however the assumption of a different value of microturbulent velocity has a negligible impact on rotational velocities and chemical abundances and it does not change our results .
we finally adopted a conservative error of 0.5 @xmath1 for all the targets .
rotational velocities have been derived for all the flames targets in our sample but bss # 12005407 , for which only an upper limit has been obtained .
conversely , only lower limits have been derived for the xshooter targets , due to the lower resolution of the spectra that prevents us to appreciate small differences at low rotational velocities .
rotational velocities for the rgb stars have been inferred from the ba ii at 4554.03 whereas rotational values for the bsss from some strong metallic lines , such as the ti ii lines at 4501.270 , 4468.492 and 4571.971 and the mg ii line at 4481 . the latter mg ii line has been used also to infer rotational velocities for the hb stars . for each star , we computed a grid of synthetic spectra with suitable atmospheric parameters and different rotational velocities .
a @xmath19 minimization between the observed spectra and the synthetic ones is then performed and used to determine the best - fit rotational velocity .
all the synthetic spectra have been computed by using the kurucz s code synthe @xcite , including the atomic data for all the lines from the most updated version of the kurucz line list by f.castelli .
model atmospheres for the synthetic spectra have been computed with atlas9 code @xcite under the assumptions of local thermodynamic equilibrium ( lte ) and plane - parallel geometry and adopting the new opacity distribution functions by @xcite , without the inclusion of the approximate overshooting @xcite .
typical uncertainties in the v@xmath4 @xmath5 measurement are of the order of 1 - 2 @xmath1 .
the rotational velocity distribution thus obtained for bsss is shown in fig .
[ rotm30 ] ( upper panel ) and it is compared with that of hb stars ( central panel ) and rgb stars ( lower panel ) .
almost all rgb stars have v@xmath4 @xmath20 , the largest value not exceeding 7 @xmath1 .
the distribution for the hb stars is wide , ranging between @xmath21 and @xmath22 .
these results are in agreement with those usually observed for this kind of stars ( * ? ? ?
* ; * ? ? ?
* ; * ? ? ?
* ; * ? ? ?
* ; * ? ? ?
* l12 ) . also the rotational velocity distribution for bsss
is spread with most red and blue bsss ( shaded and grey histograms , respectively ) having rotational velocity between 0 and 30 @xmath1 with the only exception of the fast rotating blue bss ( # 12005407 ) : for this star , the upper limit suggests a rotational velocity larger than 90 @xmath1 . finally , fig .
[ fem30 ] shows the rotational velocity as a function of temperature for all our targets and reveals no clear trends .
for all the flames targets we derived fe , mg , ti and o abundances or upper limits .
abundances of fe , o and ti for all the targets as well as mg abundances for the rgb stars have been estimated with the code gala @xcite by using the measured equivalent widths ( ews ) of the absorption lines .
conversely , spectral synthesis has been used to derive the mg abundance of bsss and hb stars from the mg ii line at @xmath0 4481 , that is an unresolved blend of three close components of the same multiplet ( so that the observed line profile significantly deviates from the gaussian approximation ) .
a @xmath19 minimization has been performed by using a grid of synthetic spectra computed with the appropriate atmospheric parameters and rotational velocities . finally for the oxygen of the bss flames targets
, we were able to obtain only upper limits , corresponding to a 3@xmath13 detection according to the formula by @xcite .
for the three xshooter targets , the combination of low metallicity and low spectral resolution does allow to analyse only a few transitions .
we measured 2 - 3 fe ii lines and the mg ii line at @xmath0 4481 .
for the coldest bss ( namely # 13000594 ) we derived only upper limits for both fe and mg .
the atomic parameters of the analysed lines are listed in table [ bsslines ] , [ rgblines ] and [ hblines ] . the used reference solar abundances are from @xcite for fe , mg and ti , and from @xcite for o. an important issue to take into account is the possible deviation from the lte assumption , particularly for the hottest targets . for the o limits we included non - lte corrections taken from the statistical equilibrium calculations of @xcite . for fe ,
mg and ti abundances , no grid of non - lte corrections are available in the literature for the range of parameters typical of our targets . based on the fact that non - lte corrections for ionized elements in hot ( a and f type ) stars are negligible with respect to those for neutral elements , whereas the opposite is true for cold stars , we obtained fe and mg abundances for the bsss and hb stars by using fe ii and mg ii lines , whereas fe i and mg i lines have been used for the rgb stars .
we did the same for ti abundances in bsss and hb stars whereas , unfortunately , this was not possible for rgb stars since only lines from ionized elements transitions are present in the spectra .
the derived abundances are listed in tables [ bssm30 ] , [ rgbm30 ] and [ hbm30 ] for bsss , rgb and hb stars , respectively . * iron * for the rgb stars we find an average iron abundance of [ fe / h]=@xmath152.28@xmath120.01 ( @xmath13=0.07 ) dex in very good agreement with results by @xcite .
the mean value for the hb stars is slightly larger , corresponding to [ fe / h]=@xmath152.13@xmath120.12 ( @xmath13=0.53 ) .
however , the large dispersion of the measures is essentially due to two out of the three stars with t@xmath2310000 k , ( see fig .
[ fem30 ] , bottom panel ) , suggesting that radiative levitation is affecting the surface abundances of those stars .
in fact , by excluding the two hb stars with the largest value of [ fe / h ] ( namely # 30016296 and # 30018857 ) , we obtain [ fe / h]=@xmath152.31@xmath120.02 ( @xmath13=0.09 ) , in agreement with rgb stars . also the distribution for the bsss
is very large and the values of [ fe / h ] systematically increase for incresing temperatures ( fig .
[ fem30 ] , bottom panel ) due to the effect of the radiative levitation .
the 5 coldest ( red ) bsss ( t@xmath14 @xmath24 7800 k ) have [ fe / h]=@xmath152.31@xmath120.04 ( @xmath13=0.08 ) , in very good agreement with rgb stars and hb stars not affected by radiative levitation .
the same iron content is confirmed also by the upper limit found for the coldest ( blue ) xshooter target ( [ fe / h]@xmath25 dex ) .
conversely , the hottest red bsss ( t@xmath14 @xmath2 7800 k ) have [ fe / h]=@xmath151.81@xmath120.22 ( @xmath13=0.38 ) , significantly larger than the mean cluster metallicity , and the bsss in the blue sequence have [ fe / h]=@xmath151.96@xmath120.10 ( @xmath13=0.35 ) . in fig .
[ ferotm30 ] rotational velocities as a function of the iron content are shown .
no trend between v@xmath4 @xmath5 and [ fe / h ] exists for the rgb stars . for hb stars ,
a mean value of @xmath0 13 @xmath1 ( with a large scatter , however ) is observed for stars with [ fe / h]@xmath262.0 dex whereas for the two more metallic stars , v@xmath4 @xmath5 drops toward values lower than @xmath0 10 @xmath1 .
finally , a possible increase of v@xmath4 @xmath5 with increasing metallicity is observed for the bsss . * magnesium * rgb stars have [ mg / fe]=0.40@xmath120.02 ( @xmath13=0.16 ) , in good agreement with the results by @xcite . for all the hb stars [ mg / fe]=0.24@xmath120.05 ( @xmath13=0.35 ) , whereas excluding the two hb stars affected by radiative levitation we obtain [ mg / fe]=0.31@xmath120.02 ( @xmath13=0.13 ) , in agreement with rgb stars . for the cold red bsss , the mean [ mg / fe ]
ratio is 0.16@xmath120.10 ( @xmath13=0.22 ) , slightly lower than the rgb and hb values .
significant difference in the [ mg / fe ] ratio has been found between the red cold bsss and the red hot bsss ( affected by radiative levitation ) that show [ mg / fe]=@xmath150.31@xmath120.32 ( @xmath13=0.56 ) .
interestingly , that difference exclusively depends on the fe abundances : in fact , [ mg / h ] ratio is @xmath152.14@xmath120.11(@xmath13=0.26 ) for the cold red bsss and @xmath152.12@xmath120.15(@xmath13=0.25 ) for the hot red bsss , suggesting that the mg abundances does not change with the occurrence of the radiative levitation .
[ mgm30 ] shows [ mg / h ] and [ mg / fe ] ratios versus effective temperature for the rgb , hb stars and bsss .
* oxygen * for bsss , only upper limits to the o abundance ( from the o i triplet at @xmath0 7774 ) can be determined because no line is detectable in these spectra .
also in our rgb spectra , the o i triplet lines are too weak to be detected , thus we measured o abundances only for hb stars . for the hb stars ( not affected by radiative levitation ) we measured [ o / h]=@xmath27 ( @xmath13=0.23 ) , in agreement with values obtained for rgb stars by @xcite . as shown in fig .
[ oxm30 ] the upper limits for almost all bsss are incompatible with the abundances of hb stars , with the only exception of bss # 11000416 .
[ olines ] shows the spectrum of bss # 11002171 zoomed in the region of the o i triplet .
synthetic spectra computed with atmospheric parameters and rotational velocity of the observed star and [ o / fe]= + 0.4 , 0.0 , @xmath150.4 dex ( solid , dotted and dashed lines , respectively ) have been superimposed and clearly show that the o abundance can not be larger than @xmath150.4 dex .
* titanium * ti abundances have been derived for all our targets by measuring the ews of a tens of ti ii lines .
results are shown in fig .
[ tim30 ] .
the ti mean abundance for the rgb stars is [ ti / h]=@xmath152.07@xmath120.01 ( @xmath13=0.08 ) , corresponding to [ ti / fe]=0.20@xmath120.01 ( @xmath13=0.11 ) .
for the hb stars [ ti / h]=@xmath152.05@xmath120.02 ( @xmath13=0.08 ) and [ ti / fe]=0.23@xmath120.03 ( @xmath13=0.11 ) , in agreement with rgb values .
for the cold red bsss we derive [ ti / fe]=0.27@xmath120.07 ( @xmath13=0.15 ) corresponding to [ ti / h]=@xmath152.03@xmath120.08 ( @xmath13=0.18 ) in good agreement with the rgb and hb values .
conversely , the abundances for the hot red bsss are larger and more scattered , corresponding to [ ti / fe]=0.34@xmath120.11 ( @xmath13=0.20 ) and [ ti / h]=@xmath151.48@xmath120.18 ( @xmath13=0.32 ) . moreover , a clearcut trend with t@xmath14 does exist , even if the two hottest ( blue ) bsss do not have the largest ti abundance .
this work presents the first investigation of the kinematical and chemical properties of bsss belonging to the two bss sequences of m30 .
all the observed bsss turn out to be members of the cluster , with no significant differences in the rv mean value and dispersion between the two groups of stars .
_ rotational velocities _ the bsss of m30 show a rotational velocity distribution wider than that derived for the rgb stars and more similiar to the distribution obtained for the hb stars .
most of the bsss have v@xmath4 @xmath2830 @xmath1 , with the only exception of the blue bss # 12005407 with v@xmath4 @xmath29 90 @xmath1 and classified as a w uma .
the rotational velocity distribution of bsss in m30 is very similar to that derived for the bss populations in 47 tuc ( f06 ) and ngc 6397 ( l12 ) , where the majority of bsss rotate slowly . on the contrary , the v@xmath4 @xmath5 distribution of bsss in m4 discussed by l10 is very broad , including a large ( @xmath040% ) fraction of _ fast rotators _ ( i.e. bsss with v@xmath4 @xmath5 larger than @xmath050 @xmath1 ) .
it is interesting to note that although the bsss in both sequences can not be defined fast rotators ( following the definition by l10 ) , when we consider the rotational velocity distribution of the bsss in each sequence , we find slightly higher values among the blue bsss . in the framework proposed by f09 , the two bss sequence of m30 are linked to different formation channels , the red sequence being populated by mt - bsss and the blue sequence by col - bsss .
the results obtained in this work indicate that no significant difference in rotational velocity characterize the bsss formed through the two mechanisms .
the current theoretical models provide conflicting predictions about bss rotational velocity ( see for instance * ? ? ?
* ; * ? ? ?
as discussed in l12 , high rotational velocities could be a transient stage in the life of some bsss , that will be slowed down during their subsequent evolution by some braking mechanisms ( that are still poorly understood , see * ? ? ?
_ chemical composition _ two main results have been derived from the chemical analysis of bsss : + ( 1 ) the iron abundance increases with effective temperature temperature : the 6 coldest bsss have [ fe / h ] ratios fully compatible with the iron content of the rgb and hb stars , while the bsss hotter than @xmath07800 k show higher iron abundances .
this trend nicely agrees with that already observed for the bsss of ngc 6397 ( l12 ) and it points toward the occurrence of particle transport mechanisms driven by the radiative levitation .
the enhancement of iron - peak elements due to this mechanism has been observed in hb stars hotter than @xmath011000 k in galactic gcs ( see e.g. * ? ? ?
* ; * ? ? ?
* ; * ? ? ?
* ) , and it is typical of stars with shallow or no convective envelopes ( as population i ms stars , @xcite ) .
_ m30 is the second cluster where the effects of radiative levitation are observed among the bsss , confirming the results obtained for ngc 6397 . _ + ( 2 ) the occurence of radiative levitation alters the surface chemical composition and prevents us to study the original chemical composition of bsss hotter than @xmath07800 - 8000 k. however ,
the 6 coldest bsss in the sample have [ fe / h ] ratios fully compatible with that of the cluster .
this confirms that the surface chemical composition of these stars is not altered and allows us to discuss the chemical composition of these bsss in terms of formation mechanisms .
the most intriguing finding concerns the o abundance that in 4 out of 5 red cold bsss results to be systematically lower than the typical values observed in the rgb and hb stars of the cluster .
the upper limits of [ o / fe ] for those 4 red bsss range from @xmath150.13 dex down to @xmath150.36 dex .
and they are incompatible with the o abundances derived for the hb stars .
unfortunately , the only cold bss along the blue sequence is # 13000594 , for which we are not able to derive significative o upper limits from the xshooter spectra .
the very low o abundance in 4 red bsss is incompatible with the o depletion associated with the second generation stars in this cluster ( in fact , it is significantly lower than that measured in hb stars and also in rgb stars ; see fig .
[ oxm30 ] and @xcite ) .
this clearly suggests that other mechanisms able to reduce the o abundance occurred . in principle
, a possibility could be that of the gravitational settling , which is due to temperature , pressure and abundance gradients , leading to the sinking of the atoms .
up to the present , no theoretical models taking into account the balance between radiative levitation and gravitation settling exist in the literature for bsss , so that it is not possible to predict the variation of surface chemical abundances due to the occurrence of the two processes . on the base of a rough reasoning
, it could be possible that the gravitational settling leads to a simultaneous depletion of both o and fe and that a larger effect might be observed on fe abundances because the fe atoms are heavier than those of o. in this case we would be able to discard that our results are the effect of the gravitational settling , due to the fact that the fe abundance for the o - depleted bsss are fully compatible with those of normal cluster stars .
however , even if we are not able to completely discard the possibility that the observed depletion is ( at least partially ) produced by the effect of gravitational settling , at the moment the hypothesis of a mt origin is the most likely , particularly according to the interpretation of the red sequence proposed by f09 .
unfortunately , the low metallicity of m30 does not allow us to measure c abundances , while the blue bsss that should not be affected by radiative levitation are too faint to be properly observed with flames .
thus , the present sample does not allow us to fully investigate whether the two bss sequences of m30 harbor stars formed from the two different mechanisms , but the strong o - depletion observed in 4 red bsss is a relevant clue in support to this scenario .
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2010 , , 719 , l121 , l10 lovisi , l. , mucciarelli , a. , lanzoni , b. , et al .
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, 2010 , spie , 7737 , 56 mucciarelli , a. , salaris , m. , lovisi , l. , et al .
2011 , , 412 , 81 mucciarelli , a. , pancino , e. , lovisi , l. , ferraro , f. r. , & lapenna , e. 2013 , arxiv:1302.3618 osterbrock , d. e. , fulbright , j. p. , martel , a. r. , keane , m. j. , trager , s. c. , & basri , g. 1996 , , 108 , 277 pace , g. recio - blanco , a. , piotto , g. , & momany , y. , 2006 , a&a , 452 , 493 peterson , r. c. , rood , r. t. , & crocker , d. a. 1995 , , 453 , 214 pietrukowicz , p. , & kaluzny , j. 2004 , , 54 , 19 rahunen , t. 1981 , , 102 , 81 sarna , m. j. , & de greve , j .-
1996 , , 37 , 11 sbordone , l. , bonifacio , p. , castelli , f. , & kurucz , r. l. 2004 , memorie della societa astronomica italiana supplementi , 5 , 93 shara , m. m. , saffer , r. a. , & livio , m. 1997 , , 489 , l59 sills , a. , adams , t. , & davies , m. b. 2005 , , 358 , 716 sills , a. , karakas , a. , & lattanzio , j. 2009 , , 692 , 1411 takeda , y. 1997 , , 49 , 471 tian , b. , deng , l. , han , z. , & zhang , x. b. 2006 , , 455 , 247 zaggia , s. r. , capaccioli , m. , piotto , g. , & stiavelli , m. 1992 , , 258 , 302 zinn , r. , & searle , l. 1976 , , 209 , 734 | we present spectroscopic observations acquired with flames and xshooter at the very large telescope for a sample of 15 blue straggler stars ( bsss ) in the globular cluster ( gc ) m30 .
the targets have been selected to sample the two bss sequences discovered , with 7 bsss along the blue sequence and 8 along the red one .
no difference in the kinematical properties of the two groups of bsss has been found . in particular , almost all the observed bsss have projected rotational velocity lower than @xmath030 @xmath1 , with only one ( blue ) fast rotating bss ( @xmath290 @xmath1 ) , identified as a w uma binary .
this rotational velocity distribution is similar to those obtained in 47 tucanae and ngc 6397 , while m4 remains the only gc studied so far harboring a large fraction of fast rotating bsss .
all stars hotter than @xmath07800 k ( regardless of the parent bss sequence ) show iron abundances larger than those measured from normal cluster stars , with a clearcut trend with the effective temperature .
this behaviour suggests that particle trasport mechanisms driven by radiative levitation occur in the photosphere of these stars , as already observed for the bsss in ngc 6397 .
finally , 4 bsss belonging to the red sequence ( not affected by radiative levitation ) show a strong depletion of [ o / fe ] , with respect to the abundance measured in red giant branch and horizontal branch stars .
this o - depletion is compatible with the chemical signature expected in bsss formed by mass transfer processes in binary systems , in agreement with the mechanism proposed for the formation of bsss in the red sequence . |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Teacher Incentive Fund Act''.
SEC. 2. TEACHER INCENTIVE FUND PROGRAM.
Part C of title II of the Elementary and Secondary Education Act of
1965 is amended by adding at the end the following:
``Subpart 6--Teacher Incentive Fund Program
``SEC. 2371. PURPOSES; DEFINITIONS.
``(a) Purposes.--The purposes of this subpart are--
``(1) to assist States, local educational agencies, and
nonprofit organizations to develop, implement, or improve
comprehensive performance-based compensation systems for
teachers and principals, especially for teachers and principals
in high-need schools, who raise student academic achievement
and close the achievement gap; and
``(2) to study and review performance-based compensation
systems for teachers and principals to evaluate their
effectiveness, fairness, quality, consistency, and reliability.
``(b) Definitions.--For purposes of this subpart:
``(1) Eligible entity.--The term `eligible entity' means--
``(A) a local educational agency (including a
charter school that is a local educational agency), or
a consortium of such agencies;
``(B) a State educational agency, or other State
agency designated by the chief executive of the State
to participate under this subpart; or
``(C) a partnership of--
``(i) one or more agencies described in
subparagraph (A) or (B), or both; and
``(ii) at least one nonprofit organization.
``(2) High-need local educational agency.--The term `high-
need local educational agency' has the meaning given the term
in section 2102.
``(3) High-need school.--The term `high-need school' has
the meaning given the term in section 2312.
``(4) Performance-based compensation system.--The term
`performance-based compensation system' means a system of
compensation for teachers and principals that--
``(A) differentiates levels of compensation
primarily on the basis of measurable increases in
student academic achievement; and
``(B) may include--
``(i) differentiated levels of compensation
on the basis of high-quality teachers' and
principals' employment and success in hard-to-
staff schools or high-need subject areas; and
``(ii) recognition of the skills and
knowledge of teachers and principals as
demonstrated through--
``(I) successful fulfillment of
additional responsibilities or job
functions; and
``(II) evidence of high achievement
and mastery of content knowledge and
superior teaching skills.
``SEC. 2372. TEACHER INCENTIVE FUND GRANTS.
``(a) In General.--From the amounts appropriated to carry out this
subpart, the Secretary is authorized to make grants on a competitive
basis to eligible entities to develop, implement, or improve
performance-based compensation systems in participating schools.
``(b) Priority.--In making such a grant, the Secretary shall give
priority to an eligible entity that concentrates its proposed
activities on teachers and principals serving in high-need schools.
``(c) Applications.--To be eligible to receive a grant under this
subpart, an eligible entity shall submit an application to the
Secretary, at such time and in such manner as the Secretary may
reasonably require, that includes--
``(1) a description of the performance-based compensation
system that the applicant proposes to develop and implement or
improve;
``(2) a description and demonstration of the support and
commitment from teachers and principals in the targeted
schools, the community, and local educational agency or
agencies for the performance-based compensation system,
including demonstration of consultation with teachers and
principals on the development and implementation of the
performance-based compensation system;
``(3) a description of how the eligible entity will develop
and implement a fair, rigorous, and objective process to
evaluate teacher, principal, and student performance, including
the baseline performance against which evaluations of improved
performance will be made;
``(4) a description and demonstration of how teacher and
principal views were included in the development of the
performance-based compensation system;
``(5) a description of the local educational agency or
local educational agencies to be served by the project,
including such demographic information about students in the
schools to be served by the project as the Secretary may
request;
``(6) information on student academic achievement, the
quality of the teachers and principals, and existing
compensation, bonuses, and incentive systems for teachers and
principals in the schools to be served by the project;
``(7) a description of how the applicant will use grant
funds under this subpart in each year of the grant;
``(8) a description of the comprehensive, focused
professional development that is aligned with student content
and achievement standards that the applicant will implement to
support the performance-based compensation system;
``(9) an explanation of how the grantee will continue its
performance-based compensation system after the grant ends;
``(10) a description, if applicable, of how the applicant
will define the term `high-quality' for the purposes of section
2371(b)(4)(B)(i), through the use of measurable indicators;
``(11) a description of the State, local, or philanthropic
funds that will be used to supplement the grant and sustain the
activities at the end of the grant period; and
``(12) A description of how the applicant will evaluate the
project annually, including any objective measures that are
clearly related to the goals for the project and information on
how the evaluation will produce quantitative and qualitative
data.
``(d) Use of Funds.--
``(1) In general.--A grantee shall use grant funds provided
under this subpart only to develop, implement, or improve, in
collaboration with teachers, principals, other school
administrators, and members of the public, a performance-based
compensation system consistent with the requirements of this
subpart.
``(2) Authorized activities.--Authorized activities under
this subpart may include the following:
``(A) Developing appraisal systems that reflect
clear and fair measures of student academic
achievement.
``(B) Developing appraisal systems that reflect
clear and fair measures of teacher and principal
performance based on demonstrated improvements in
student academic achievement.
``(C) Conducting outreach within the local
educational agency (or agencies) or the State to gain
input on how to construct the appraisal system and to
develop support for it.
``(D) Paying, as part of a comprehensive
performance-based compensation system, bonuses and
increased salaries to teachers and principals who raise
student academic achievement, so long as the grantee
uses an increasing share of non-Federal funds to pay
these monetary rewards each year of the grant.
``(E) Paying, as part of a comprehensive
performance-based compensation system, additional
bonuses to teachers who both raise student academic
achievement and either teach in high-need schools or
teach subjects that are difficult to staff, or both, so
long as the grantee uses an increasing share of non-
Federal funds to pay these monetary rewards each year
of the grant.
``(F) Paying, as part of a comprehensive
performance-based compensation system, additional
bonuses to principals who both raise student academic
achievement and serve in high-need schools, so long as
the grantee uses an increasing share of non-Federal
funds to pay these monetary rewards each year of the
grant.
``(e) Duration of Grants.--
``(1) In general.--The Secretary may make grants under this
section for periods of up to 5 years.
``(2) Limitation.--An agency described in subparagraph (A)
of section 2371(b)(1) may receive (whether individually or as
part of a consortium or partnership) a grant under this subpart
only once. Such an agency may continue to receive that grant
for the period of that grant, but shall not receive (whether
individually or as part of a consortium or partnership) any
other grant under this subpart.
``(f) Equitable Distribution.--To the extent practicable, the
Secretary shall ensure an equitable geographic distribution of grants
under this section.
``(g) Matching Requirement.--
``(1) Each eligible entity that receives a grant under this
section shall provide, from non-Federal sources, an amount
(which may be provided in cash or in kind) to carry out the
activities supported by the grant equal to--
``(A) for the first year of the grant, 25 percent
of the amount received for that year under the grant;
``(B) for the second year, 30 percent;
``(C) for the third year, 35 percent;
``(D) for the fourth year, 40 percent; and
``(E) for the fifth year, 50 percent.
``(2) The Secretary may waive all or part of the matching
requirement described in paragraph (1) for any fiscal year for
an eligible entity described in section 2371(b)(1)(A) if that
eligible entity is a high-need local educational agency, a
consortium of high-need local educational agencies, or a
charter school that is a high-need local educational agency and
the Secretary determines that applying the matching requirement
to such eligible entity would result in serious hardship or an
inability to carry out the activities described in subsection
(d).
``(h) Supplement, Not Supplant.--Grant funds provided under this
section shall be used to supplement, not supplant, other Federal or
State funds.
``SEC. 2373. REPORT AND EVALUATION.
``(a) Report.--The Secretary shall provide an annual report on the
implementation of the program to the Congress.
``(b) Evaluation.--
``(1) In general.--The Secretary shall, through grant or
contract, carry out an independent evaluation of the program
under this subpart.
``(2) Content.--The evaluation shall measure--
``(A) the effectiveness of the program in improving
student academic achievement;
``(B) the satisfaction of the participating
teachers or principals; and
``(C) the extent to which the program assisted the
eligible entities in recruiting and retaining high-
quality teachers and principals, especially in hard-to-
staff subject areas.
``SEC. 2374. AUTHORIZATION OF APPROPRIATIONS.
``(a) In General.--There are authorized to be appropriated to carry
out this subpart such sums as may be necessary for fiscal year 2008 and
each of the succeeding 5 fiscal years.
``(b) Reservation.--The Secretary may reserve not more than 3
percent of the funds appropriated to carry out this subpart for any one
fiscal year for the cost of the evaluation under section 2373(b) and
for technical assistance and program outreach.''. | Teacher Incentive Fund Act - Amends the Elementary and Secondary Education Act of 1965 to create a Teacher Incentive Fund program of competitive grants to assist states, local educational agencies (LEAs), and nonprofit organizations to develop and implement, or improve, appraisal and performance-based compensation systems to reward teachers and principals who raise student academic achievement and close the achievement gap, especially in the highest-need LEAs.
Increases required non-federal contributions to the program, on a graduated basis, from an amount equal 25% of the grant amount received in the first year to 50% of the grant amount received in the grant's fifth and final year. Allows the Secretary of Education to waive such matching requirement for high-need LEAs. |
Imagine Kelsey Grammer as the next resident of Gracie Mansion.
The “Frasier” star — a longtime conservative Republican — now says he plans to run for office, perhaps right here in New York, when he gives up acting.
“I have had a great career and extraordinary opportunities,” he told The Post. “But I look at my political aspirations as that last piece of my life — where I hope to do something good for people and pay back a little.”
The leap from actor to politician isn’t that great, the actor believes. Both, he says, require a “narcissistic personality” to succeed.
“You certainly have to have a resilient ego,” Grammer says.
Grammer — who left the Broadway revival of “La Cage Aux Folles” last February — is set to play fictional Chicago Mayor Tom Kane in a new drama called “Boss,” set to premiere this fall on the Starz network.
And the prospect of the new role has, it seems, got him thinking about doing something like it in real life.
Grammer is not only one of Hollywood’s rare anti-tax, small-government Republicans, but he is an activist. Unlike a lot of actors who like to give their opinions on issues, he campaigns for and travels with candidates he likes — and he is a big-time giver to conservative causes.
In the last presidential election, he endorsed Rudy Giuliani but ended up going on the road for Sen. John McCain.
He is also the major bankroll behind a small cable channel called Rightnetwork that launched last September and goes by the slogan “All that’s Right with the world.”
“It is not unfamiliar for me to have a point of view that might be considered out of the norm in my community,” he says.
Grammer, 56, is light on specifics about when his days as an actor might end or which office he has his eye set on.
But he is clear that he has moved from LA permanently and is a New Yorker now. If and when he runs, it would likely be here, he says.
What is left unspoken is the considerable money — mostly from the reruns of “Frasier” — he could pour into an election, if he chose to.
While not in the same league as New York’s current mayor, multi-billionaire Mike Bloomberg, Grammer’s personal-wealth reportedly ranges up to nearly $100 million — a good sum with which to start a political career.
Already this week, he is taking a side on the debt-ceiling crisis.
“Even the solution they are talking about now — the 10-year, $3-trillion solution — that has to be paid for. Nobody is talking about actually getting rid of the debt that exists already,” he says. “That doesn’t make any sense. It’s first-grade math.”
Grammer says he began to mull the prospect of changing his life after suffering a minor heart-
attack three years ago.
“I spent several months sort of looking at my own life,” he says. “And I just decided I didn’t want to have [“Hank,” the ill-fated sitcom he starred in last year for Fox] be my last story.
“So, I decided that it was time to make changes that involved my career, as well as my personal life. Doing a drama started to make really good sense, because it took me back to my roots.” ||||| November, 2004, New Mexico. Bud is a slacker with one good thing in his life, his engaging fifth-grade daughter Molly. On election day, Bud is supposed to meet her at the polling place. When he doesn't show, she sneaks a ballot and is about to vote when the power goes off. It turns out that New Mexico's electoral votes will decide the contest, and there it's tied with one vote needing recasting - Bud's. The world's media and both presidential candidates, including the current President, descend on Bud in anticipation of his re-vote in two weeks. Can the clueless Bud, even with the help of Molly and a local TV reporter, handle this responsibility? Written by <jhailey@hotmail.com> | – Kelsey Grammer has played a president, and in an upcoming TV series he'll play a mayor ... so why not run for political office in real life? That's what he may very well do after he retires from acting, Grammer tells the New York Post, although he's vague on when that might be or what he might run for. "I look at my political aspirations as that last piece of my life—where I hope to do something good for people and pay back a little," says the conservative Republican, who endorsed Rudy Giuliani and campaigned for John McCain in the last presidential election. Grammer, who is for small government and against taxes, is already a political activist: He has traveled with candidates he supports, including McCain, and the Post calls him a "big-time giver to conservative causes." He's also bankrolling Rightnetwork, a small cable channel with the slogan, "All that's Right with the world." He would likely run in New York, where he moved to from Los Angeles, Grammer says. And his acting experience would help him, he theorizes: Both acting and politics require a "narcissistic personality" and "a resilient ego." |
the interest on the properties of open and hidden charm mesons was initiated in the context of heavy - ion collisions in connection to the charmonium suppression @xcite as a probe for the formation of quark - gluon plasma .
recently charmed baryonic resonances have received a lot of attention motivated by the discovery of quite a few new states by the cleo , belle and babar collaborations @xcite . moreover
, the future fair facility at gsi @xcite will move from the light quark sector to the heavy one and will face new challenges where charm plays a dominant role .
the cbm ( compressed baryonic matter ) experiment at fair / gsi will extend the gsi programme for in - medium modification of hadrons in the light quark sector , and provide first insight into the charm - nucleus interaction .
therefore , the modifications of the properties of open and hidden charm mesons in a hot and dense environment are being the focuss of recent studies . the in - medium modification of the properties of open - charm mesons ( @xmath2 and @xmath3 may help to explain the @xmath4 suppression in a hadronic environment as well as the possible formation of @xmath2-mesic nuclei .
moreover , changes in the properties of open - charm mesons will affect the renormalization of charm and hidden charm scalar meson resonances in nuclear matter , providing information about their nature .
in the present paper we obtain the properties of open - charm mesons in dense matter within a self - consistent approach in coupled channels .
we study the behaviour of dynamically generated charmed baryonic resonances as well as the open - charm meson spectral functions in this dense medium .
we then analyze the effect of the self - energy of @xmath2 mesons on the properties of dynamically - generated charm and hidden charm scalar resonances , such as the @xmath0 and the predicted @xmath1 resonances .
we finally provide some recent results on @xmath2-nucleus bound states .
the self - energy and , hence , the spectral function for open - charm ( @xmath2 and @xmath5 ) mesons is obtained following a self - consistent coupled - channel procedure .
the transition potential of the bethe - salpeter equation or @xmath6-matrix ( @xmath6 ) is derived from effective lagrangians , which will be discussed in the following .
the self - energy is then obtained summing the transition amplitude @xmath6 for the different isospins over the nucleon fermi distribution at a given temperature , @xmath7 : @xmath8\ , \label{eq : selfd}\end{aligned}\ ] ] where @xmath9 and @xmath10 are the total energy and momentum of the meson - nucleon pair in the nuclear matter rest frame , and ( @xmath11,@xmath12 ) and ( @xmath13,@xmath14 ) stand for the energy and momentum of the meson and nucleon , respectively , also in this frame .
the self - energy must be determined self - consistently since it is obtained from the in - medium amplitude @xmath6 which contains the meson - baryon loop function , and this last quantity itself is a function of the self - energy .
then , the meson spectral function reads @xmath15 meson spectral function for different momenta , temperatures and densities for the su(4 ) model .
we show the @xmath2 meson free mass for reference ( dotted lines ) .
[ fig1],scaledwidth=45.0%,height=264 ] the open - charm meson spectral functions are obtained from the bethe - salpeter equation in coupled - channels taking , as bare interaction , a type of broken @xmath17 @xmath18-wave weinberg - tomozawa ( wt ) interaction supplemented by an attractive isoscalar - scalar term and using a cutoff regularization scheme .
this cutoff is fixed by generating dynamically the @xmath19 @xmath20 resonance . a new resonance in @xmath21 channel , @xmath22 ,
is generated @xcite .
the in - medium solution at finite temperature incorporates pauli blocking , baryon mean - field bindings and @xmath23 and @xmath2 meson self - energies @xcite . in fig .
[ fig1 ] we display the @xmath2 meson spectral function for different momenta , temperatures and densities . at @xmath24
the spectral function shows two peaks .
the @xmath25 excitation is seen at a lower energy whereas the second one at higher energy corresponds to the quasi(d)-particle peak mixed with the @xmath26 state .
those structures dilute with increasing temperature while the quasiparticle peak gets closer to its free value becoming narrower , as the self - energy receives contributions from higher momentum @xmath27 pairs where the interaction is weaker .
finite density results in a broadening of the spectral function because of the increased phase space , as previously observed for the @xmath28 in dense matter @xcite .
heavy - quark symmetry ( hqs ) is a qcd spin - flavor symmetry that appears when the quark masses , such as the charm mass , become larger than the typical confinement scale .
the spin interactions then vanish for infinitely massive quarks and heavy hadrons come in doublets ( if the spin of the light degrees of freedom is not zero ) , which are degenerate in the infinite quark - mass limit . and
this is the case for the @xmath2 meson and its vector partner , the @xmath29 meson .
therefore we calculate the self - energy and , hence , the spectral function of the @xmath2 and @xmath29 mesons in nuclear matter from a simultaneous self - consistent calculation in coupled channels that incorporates hqs .
we extend the wt meson - baryon lagrangian to the @xmath30 spin - flavor symmetry group as we include pseudoscalars and vector mesons together with @xmath31 and @xmath32 baryons @xcite , following the steps for @xmath33 of ref .
the @xmath30 spin - flavor is , however , strongly broken in nature . so that we take into account mass breaking effects by adopting the physical hadron masses in the tree level interactions and in the evaluation of the kinematical thresholds of different channels , as done in the previous @xmath17 models .
moreover , we consider the difference between the weak non - charmed and charmed pseudoscalar and vector meson decay constants .
we also improve on the regularization scheme in nuclear matter going beyond the usual cutoff scheme @xcite . and @xmath29 spectral functions in nuclear matter at @xmath34 mev / c in the su(8 ) scheme .
we show the @xmath2 and @xmath29 meson free masses for reference ( dotted lines ) .
[ fig2],title="fig:",scaledwidth=45.0%,height=264 ] and @xmath29 spectral functions in nuclear matter at @xmath34 mev / c in the su(8 ) scheme .
we show the @xmath2 and @xmath29 meson free masses for reference ( dotted lines ) .
[ fig2],title="fig:",scaledwidth=45.0%,height=207 ] as seen on the l.h.s . of fig .
[ fig2 ] , the @xmath30 model generates a wider spectrum of resonances with charm @xmath35 and strangeness @xmath36 compared to the @xmath17 models . while the parameters of both @xmath17 and @xmath30 models are fixed by the ( @xmath19 , @xmath37 ) @xmath38 resonance , the fact that we incorporate vectors mesons in the @xmath30 scheme generates naturally @xmath39 resonances , such as @xmath40 , @xmath41 , @xmath42 and @xmath43 , some of which might be identified experimentally @xcite .
new resonances are also produced for @xmath37 , as @xmath44 and @xmath45 , while others are not obtained in @xmath17 models because of the different symmetry breaking pattern used in both models .
the modifications of the mass and width of these resonances in the nuclear medium are strongly dependent on the coupling to channels with @xmath2 , @xmath29 and @xmath46 content , which are modified in the nuclear medium . moreover
, the resonances close to the @xmath27 or @xmath47 thresholds change their properties more evidently as compared to those far offshell .
the improvement in the regularization / renormalization procedure of the intermediate propagators in the nuclear medium beyond the usual cutoff method has also an important effect on the in - medium changes of the dynamically - generated resonances , in particular , for those lying far offshell from their dominant channel , as the case of the @xmath38 . on the r.h.s of fig .
[ fig2 ] we display the @xmath2 and @xmath29 spectral functions , which show then a rich spectrum of resonance - hole states .
the @xmath2 meson quasiparticle peak mixes strongly with @xmath48 and @xmath49 states while the @xmath50 is clearly visible in the low - energy tail .
the @xmath29 spectral function incorporates the @xmath39 resonances , and the quasiparticle peak fully mixes with @xmath51 and @xmath52 . as density increases , these @xmath53 modes tend to smear out and the spectral functions broaden with increasing phase space .
the analysis of the properties of scalar resonances in nuclear matter is a valuable tool in order to understand the nature of those states , whether they are @xmath54 , molecules , mixtures of @xmath54 with meson - meson components , or dynamically generated resonances resulting from the interaction of two pseudoscalars .
we study the charmed resonance @xmath0 @xcite together with a hidden charm scalar meson , @xmath1 , predicted in ref .
@xcite , which might have been observed by the belle collaboration @xcite via the reanalysis of ref .
those resonances are generated dynamically solving the coupled - channel bethe - salpeter equation for two pseudoscalars @xcite .
the kernel is derived from a @xmath17 extension of the @xmath55 chiral lagrangian used to generate scalar resonances in the light sector .
the @xmath17 symmetry is , however , strongly broken , mostly due to the explicit consideration of the masses of the vector mesons exchanged between pseudoscalars @xcite .
the transition amplitude around each resonance for the different coupled channels gives us information about the coupling of this state to a particular channel .
the @xmath0 mainly couples to the @xmath56 system , while the hidden charm state @xmath1 couples most strongly to @xmath57 .
then , any change in the @xmath2 meson properties in nuclear matter will have an important effect on these resonances .
those modifications are given by the @xmath2 meson self - energy in the @xmath17 model without the phenomenological isoscalar - scalar term , but supplemented by the @xmath58-wave self - energy through the corresponding @xmath53 excitations @xcite .
( left ) and @xmath1 ( right ) resonances in nuclear matter [ fig4],title="fig:",scaledwidth=40.0%,height=207 ] ( left ) and @xmath1 ( right ) resonances in nuclear matter [ fig4],title="fig:",scaledwidth=40.0%,height=207 ] in fig .
[ fig4 ] the resonances @xmath0 and @xmath1 are shown by displaying the squared transition amplitude for the corresponding dominant channel at different densities .
the @xmath0 and @xmath1 resonances , which have a zero and small width , develop widths of the order of 100 and 200 mev at normal nuclear matter density , respectively .
the origin can be traced back to the opening of new many - body decay channels as the @xmath2 meson gets absorbed in the nuclear medium via @xmath27 and @xmath59 inelastic reactions .
we do not extract any clear conclusion for the mass shift .
we suggest to look at transparency ratios to investigate those in - medium widths .
this magnitude , which gives the survival probability in production reactions in nuclei , is very sensitive to the absorption rate of any resonance inside nuclei , i.e. , to its in - medium width @xcite .
.(b,@xmath60 ) in mev for @xmath61nucleus bound states [ cols="^,^,^,^,^",options="header " , ]
the possible formation of @xmath2-meson bound states in @xmath62pb was predicted @xcite relying upon a strong mass shift for @xmath2 mesons in the nuclear medium based on a quark - meson coupling ( qmc ) model @xcite . the experimental observation of those bound states , though , might be problematic since , even if there are bound states , their widths could be very large compared to the separation of the levels .
this is indeed the case for the potential derived from a su(4 ) @xmath16-vector meson exchange model @xcite .
however , the model that incorporates heavy - quark symmetry in the charm sector @xcite generates widths of the @xmath2 meson in nuclear matter sufficiently small with respect to the mass shift to form bound states for @xmath2 mesons in nuclei . in order to compute de @xmath2-nucleus bound states
, we solve the klein - gordon equation ( kge ) .
we concentrate on @xmath63-nucleus bound states since the coulomb interaction will prevent the formation of bound states for @xmath64 mesons .
the potential that enters in the kge is an energy - dependent one that results from the zero - momentum @xmath2-meson self - energy at the quasiparticle energy within the su(8 ) model . in table
[ table ] we show the binding energies ( @xmath65 ) and widths ( @xmath60 ) of bound states of the @xmath63 meson in different nuclei . we observe that the @xmath63-nucleus states are weakly bound with significant widths @xcite in contrast to previous results using the qmc model , in particular , for @xmath62pb @xcite .
we have studied the properties of open - charm mesons in dense matter within a self - consistent coupled - channel approach taking , as bare interaction , different effective lagrangians .
the in - medium solution accounts for pauli blocking effects and meson self - energies .
we have analyzed the behaviour in this dense environment of dynamically - generated charmed baryonic resonances together with the evolution with density and temperature of the open - charm meson spectral functions .
we have discussed the implications of the properties of charmed mesons on the @xmath0 and the predicted @xmath1 in nuclear matter , and suggested to look at transparency ratios to investigate the changes in width of those resonances in nuclear matter .
we have finally analyzed the possible formation of @xmath2-mesic nuclei .
only weakly bound @xmath63-nucleus states seem to be feasible within the su(8 ) scheme that incorporates heavy - quark symmetry .
acknowledges support from the rff program of the university of groningen .
this work is partly supported by the eu contract no .
mrtn - ct-2006 - 035482 ( flavianet ) , by the contracts fis2008 - 01661 and fis2008 - 01143 from micinn ( spain ) , by the spanish consolider - ingenio 2010 programme cpan ( csd2007 - 00042 ) , by the generalitat de catalunya contract 2009sgr-1289 and by junta de andaluca under contract fqm225 .
we acknowledge the support of the european community - research infrastructure integrating activity `` study of strongly interacting matter '' ( hadronphysics2 , grant agreement n. 227431 ) under the 7th framework programme of eu .
l. tolos , a. ramos , and a. polls , _ phys .
c _ * 65 * , 054907 ( 2002 ) ; l. tolos , a. ramos , and e. oset , _ phys .
c _ * 74 * , 015203 ( 2006 ) ; l. tolos , d. cabrera , and a. ramos , _ phys .
c _ * 78 * , 045205 ( 2008 ) ; e. hernandez , and e. oset , _
z. phys . a _ * 341 * , 201 ( 1992 ) . m. kaskulov , e. hernandez , and e. oset , _ eur .
phys . j. a _ * 31 * , 245 ( 2007 ) .
k. tsushima , d. h. lu , a. w. thomas , k. saito , and r. h. landau , _ phys .
c _ * 59 * , 2824 ( 1999 ) . | we obtain the properties of charmed mesons in dense matter using a coupled - channel approach which accounts for pauli blocking effects and meson self - energies in a self - consistent manner .
we study the behaviour of dynamically - generated baryonic resonances together with the open - charm meson spectral functions in this dense nuclear environment .
we discuss the implications of the in - medium properties of open - charm mesons on the @xmath0 and the predicted @xmath1 scalar resonances , and on the formation of @xmath2-mesic nuclei .
address = theory group . kvi .
university of groningen , zernikelaan 25 , 9747 aa groningen , the netherlands address = instituto de fsica corpuscular ( centro mixto csic - uv ) institutos de investigacin de paterna , aptdo .
22085 , 46071 , valencia , spain address = departamento de fsica atmica , molecular y nuclear , universidad de granada , e-18071 granada , spain address = instituto de fsica corpuscular ( centro mixto csic - uv ) institutos de investigacin de paterna , aptdo .
22085 , 46071 , valencia , spain address = instituto de fsica corpuscular ( centro mixto csic - uv ) institutos de investigacin de paterna , aptdo .
22085 , 46071 , valencia , spain address = instituto de fsica corpuscular ( centro mixto csic - uv ) institutos de investigacin de paterna , aptdo .
22085 , 46071 , valencia , spain address = departament destructura i constituents de la matria , universitat de barcelona , diagonal 647 , 08028 barcelona , spain |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Federal Lands Recreation Fee
Authority Act''.
SEC. 2. RECREATION FEES ON FEDERAL LANDS.
(a) General Authority.--Except as provided in subsection (b):
(1) The Secretary of the Interior is authorized to collect
recreation fees, including entrance and use fees, on the
following lands administered by the Secretary:
(A) Units of the National Park System;
(B) Units of the National Wildlife Refuge System;
and
(C) National monuments and national conservation
areas administered by the Bureau of Land Management.
(2) The Secretary of Agriculture is authorized to collect
recreation fees, including entrance and use fees, on the
following National Forest System lands administered by the
Secretary:
(A) National monuments;
(B) National volcanic monuments;
(C) National scenic areas; and
(D) National recreation areas.
(3) The Secretary of the Interior, with respect to lands
administered by the Bureau of Land Management, and the
Secretary of Agriculture, with respect to National Forest
System lands, is also authorized to collect fees at areas not
described in paragraphs (1) and (2) if--
(A) such area is managed primarily for outdoor
recreation purposes and contains at least one major
recreation attraction;
(B) such area has had substantial Federal
investments, as determined by the appropriate
Secretary, in--
(i) providing facilities or services to the
public; or
(ii) restoring resource degradation caused
by public use; and
(C) public access to the area is provided in such a
manner that entrance fees can be efficiently collected
at one or more centralized locations.
(5) The Secretary of the Interior or the Secretary of
Agriculture, as appropriate, may reduce or waive any fee
authorized under this Act, as appropriate.
(6) For each unit or area collecting an entrance fee, the
appropriate Secretary shall establish at least one day each
year during periods of high visitation as a ``Fee Free Day''
when no entrance fee shall be charged.
(7) No recreation fees of any kind shall be imposed or
collected for outdoor recreation purposes on Federal lands
under the jurisdiction of the Secretary of the Interior or the
Secretary of Agriculture, except as provided in this Act.
(b) Prohibition on Fees.--(1) No recreation fees shall be charged
under this Act--
(A) for travel by private, noncommercial vehicle over any
national parkway or any road or highway established as a part
of the National Federal Aid System, as defined in section 101
of title 23, United States Code, which is commonly used by the
public as a means of travel between two places, either or both
of which are outside of the fee area;
(B) for travel by private, noncommercial vehicle over any
road or highway to any land in which a person has any property
right if such land is within the unit or area at which
recreation fees are charged;
(C) for any person who has a right of access for hunting or
fishing privileges under a specific provision of law or treaty;
or
(D for any person who is engaged in the conduct of official
business within the unit or area at which recreation fees are
charged.
(2) Entrance fees shall not be charged--
(A) for any person under 16 years of age;
(B) for admission of organized school groups or outings
conducted for education purposes by schools or other bona fide
educational institutions;
(C) for any area containing deed restrictions on charging
fees;
(D) for any person entering a national wildlife refuge who
is the holder of a valid migratory bird hunting and
conservation stamp issued under section 2 of the Act of March
16, 1934 (16 U.S.C. 718b) (commonly known as the Duck Stamp
Act);
(E) for any person holding a valid Golden Eagle Passport,
Golden Age Passport, Golden Access Passport, or for entrance to
units of the National Park System, a National Parks Passport;
and
(F) at the following areas administered by the National
Park Service:
(i) U.S.S. Arizona Memorial;
(ii) Independence National Historical Park;
(iii) any unit of the National Park System within
the District of Columbia or the Arlington House--Robert
E. Lee National Memorial in Virginia; and
(iv) any unit of the National Park System located
in Alaska, with the exception of Denali National Park
and Preserve (notwithstanding section 203 of the Alaska
National Interest Lands Conservation Act (16 U.S.C.
410hh-2)); and
(G) in Smoky Mountains National Park, unless entrance fees
are charged on main highways and thoroughfares, no fees shall
be charged for entrance on other routes into the park, or any
part thereof.
(c) Fee Considerations.--(1) Recreation fees charged by the
Secretary of the Interior or the Secretary of Agriculture shall be fair
and equitable, taking into consideration--
(A) the direct and indirect cost to the Federal agency
involved;
(B) the benefits and services provided to the visitor;
(C) the public policy and management objectives served;
(D) costs to the visitor;
(E) the effect of multiple fees charged within the same
area;
(F) fees charged at comparable sites by other public
agencies; and
(G) the economic and administrative feasibility of fee
collection at the site.
(2) The Secretary of the Interior and the Secretary of Agriculture
shall work cooperatively to ensure that comparable fees and services
are established on Federal lands under each Secretary's jurisdiction,
and that guidelines for assessing the type and amount of recreation
fees are consistent between areas under each Secretary's jurisdiction.
(3) The Secretary of the Interior and the Secretary of Agriculture
shall, to the extent practicable, seek to minimize multiple fees within
specific units or areas.
(d) Recreation Use Fees.--(1) The Secretary of the Interior and the
Secretary of Agriculture may provide for the collection of recreation
use fees where the Federal agency develops, administers, provides, or
furnishes at Federal expense, specialized outdoor recreation sites,
facilities, equipment, or services.
(2) As used in this subsection, the term ``specialized outdoor
recreation sites, facilities, equipment, or services'' includes--
(A) a developed campground;
(B) a swimming site;
(C) a boat launch facility;
(D) a managed parking lot;
(E) facility or equipment rental;
(F) an enhanced interpretive program;
(G) a reservation service; or
(H) a transportation service.
(3) Recreation use fees may not be charged for--
(A) general access to an area;
(B) access to a visitor center;
(C) a dispersed area with little or no Federal investment;
(D) a scenic overlook or wayside;
(E) drinking fountains or restrooms;
(F) undeveloped parking;
(G) picnic tables (when not part of a developed campground
or recreation area);
(H) special attention or extra services necessary to meet
the needs of the disabled; or
(I) any nonrecreational activity authorized under a valid
permit issued under any other Act.
(e) Special Recreation Permit Fee.--The Secretary of the Interior
or the Secretary of Agriculture may require a special recreation permit
and may charge a special recreation permit fee for recreation use
involving a group activity, a commercial tour, a commercial aircraft
tour, a recreation event, use by a motorized recreation vehicle, a
competitive event, and an activity where a permit is required to ensure
resource protection or public safety.
SEC. 3. ANNUAL PASSES.
(a) In General.--The Secretary of the Interior and the Secretary of
Agriculture shall jointly establish procedures for the issuance of, and
make available the following passes:
(1) Golden eagle passport.--An annual admission permit, to
be known as the ``Golden Eagle Passport'', to be valid for a
period of one year for admission into any unit or area
collecting an entrance fee under this Act.
(2) Golden age passport.--A lifetime admission permit to
any citizen of, or person domiciled in the United States sixty-
two years of age or older, entitling the permittee to admission
into any unit or area collecting an entrance fee under this
Act.
(3) Golden access passport.--A lifetime admission permit to
any citizen of, or person domiciled in the United States who is
blind or permanently disabled, to be issued without cost.
(4) Other passes.--The Secretary of the Interior and the
Secretary of Agriculture may develop such other annual,
regional or site-specific passes as they deem appropriate.
(b) Terms and Conditions.--
(1) Unless determined otherwise by the Secretary of the
Interior and the Secretary of Agriculture, the passes
authorized under this section shall be issued under the same
terms and conditions as existed for such passes as of the date
of enactment of this Act.
(2) The Secretaries shall develop such terms and conditions
for the passes authorized in this section as they deem
necessary.
(c) National Park Passport.--Nothing in this Act affects the
authority of the Secretary of the Interior to issue national park
passports, as authorized in title VI of the National Parks Omnibus
Management Act of 1998 (16 U.S.C. 5991 et seq.).
SEC. 4. ADMINISTRATION.
(a) In General.--The Secretary of the Interior and the Secretary of
Agriculture shall establish guidelines identifying the process by which
the agencies under each Secretary's jurisdiction shall establish and
change the amounts charged for any recreation fee, including entrance
fees, recreation use fees, or special recreation permit fees collected
under this Act. Such guidelines shall require that the agencies
coordinate with each other, to the extent practicable, when
establishing or changing fees.
(b) Notice.--The Secretary of the Interior or the Secretary of
Agriculture, as appropriate, shall post clear notice of any entrance
fee and available passes at appropriate locations within each area
where a recreation fee is charged. Notice shall also be included in
publications distributed at the unit or area where the fee is
collected. The Secretaries shall jointly take such actions as may be
necessary to provide information to the public on all available passes
authorized by this Act.
(c) Notice of Recreation Fee Projects.--The Secretary of the
Interior and the Secretary of Agriculture shall, to the extent
practicable, post clear notice of where work is being done using fee
revenues collected under this Act.
(d) Fee Management Agreements.--Notwithstanding the Federal Grant
and Cooperative Agreements Act of 1977 (31 U.S.C. 6301 et seq.), the
Secretary of the Interior and the Secretary of Agriculture may enter
into fee management agreements, that provide for reasonable commissions
or reimbursements, with any governmental or nongovernmental entities to
provide fee collection and processing services, including visitor
reservation services.
(e) Volunteers.--The Secretary of the Interior and the Secretary of
Agriculture may use volunteers, as appropriate, to collect fees and
sell passes authorized by this Act.
SEC. 5. EXPENDITURE OF FEES.
(a) Special Account.--The Secretary of the Treasury shall establish
a separate special account in the Treasury for each Federal agency
collecting recreation fees under this Act. Amounts collected by each
agency under this Act shall be deposited into its special account in
the Treasury, and shall be available for expenditure by the appropriate
agency, without further appropriation, to remain available until
expended.
(b) Distribution.--
(1) Eighty percent of the amounts collected at a specific
unit or area shall remain available for expenditure without
further appropriation, at the unit or area where the fees were
collected, except that the Secretary of the Interior or the
Secretary of Agriculture, as appropriate, may reduce the local
allocation amount to not less than 60 percent of the fees
collected if the Secretary determines that the unit or area's
revenues in any specific fiscal year exceed its reasonable
needs for which expenditures may be made.
(2) Amount not retained at the site or area collecting the
fee shall remain available for expenditure without further
appropriation to the Federal agency administering the site, for
distribution in accordance with national priority needs within
such agency.
(3) Revenues from the sale of annual passes shall be
distributed in accordance with revenue sharing agreements
developed by the Secretary of the Interior and the Secretary of
Agriculture.
(c) Use of Fee Revenues.--Amounts made available under subsection
(b)(1) for expenditure at a specific unit or area shall be accounted
for separately from amounts available under (b)(2). Both amounts shall
be used for resource preservation, backlogged repair and maintenance
projects (including projects related to health and safety),
interpretation, signage, habitat for facility enhancement, law
enforcement related to public use, maintenance, and direct operating or
capital costs associated with the recreation fee program.
SEC. 6. CONFORMING AMENDMENTS.
(a) Repeal of Other Fee Authorities.--Section 4 of the Land and
Water Conservation Fund Act (16 U.S.C. 4601-4a) and section 315 of
Public Law 104-134, as amended (16 U.S.C. 4601-4a note), are repealed,
except that the repeal of such provisions shall not affect the
expenditure of revenues already obligated. All unobligated amounts as
of the date of enactment of this Act shall be transferred to the
appropriate special account established under this Act and shall be
available as provided in this Act.
(b) Federal and State Law Unaffected.--Nothing in this Act shall be
construed--
(1) to authorize Federal hunting or fishing licenses or
fees;
(2) to authorize charges for commercial or other activities
not related to recreation;
(3) to affect any rights or authority of the States with
respect to fish and wildlife;
(4) to repeal or modify any provision of law that provides
that any fees or charges collected at specific Federal areas be
used for, or created to specific purposes or special funds as
authorized by that provision of law; or
(5) to repeal or modify any provision of law authorizing
States or political subdivisions thereof to share in revenues
from Federal lands. | Federal Lands Recreation Fee Authority Act - Authorizes the collection of recreation, use, and entrance fees on certain lands administered by the Secretary of the Interior and the Secretary of Agriculture.Prohibits the charging of recreation fees for: (1) travel over roads established as part of the National Federal Aid System; (2) travel by a person who has a property right to land within the unit in which recreation fees are charged; (3) any person who has a right of access for hunting or fishing privileges; and (4) any person engaged in official business.Prohibits the charging of entrance fees for: (1) persons under 16 years of age; (2) admission of organized school groups; (3) any area containing deed restrictions on charging fees; (4) persons holding a migratory bird hunting and conservation stamp under the Duck Stamp Act; (5) persons holding a Golden Eagle Passport, Golden Age Passport, Golden Access Passport, or National Parks Passport; and (6) specified National Park Service areas.Prohibits the charging of recreation use fees for: (1) general access to an area; (2) visitor centers; (3) dispersed areas with little Federal investment; (4) scenic overlooks or waysides; (5) drinking fountains or restrooms; (6) undeveloped parking; (7) picnic tables that are not part of a developed recreation area; and (8) services necessary for the disabled.Authorizes the issuance of annual passes, including the Golden Eagle Passport, Golden Age Passport, and Golden Access Passport.Repeals other fee authorities under the Land and Water Conservation Fund Act. |
A renewed effort to find missing Avro Arrow model planes, believed to be at the bottom of Lake Ontario since the 1950s, launched Friday.
An underwater vehicle was sent into Lake Ontario by the Raise the Arrow project, a collaboration between several private companies that are working with the assistance of the Canadian Coast Guard and the Royal Canadian Military Institute.
The Thunderfish autonomous underwater vehicle, a programmable submarine, is now busy surveying the section of the lake where the models are believed to be.
"We're starting with the high probability areas," said John Burzynski, head of OEX, the group leading the recovery efforts.
The submarine is accompanied by a crew on a boat who stay nearby to watch out for boat traffic.
A crew will travel with the submarine to ensure it is not impacted by boat traffic on Lake Ontario. (CBC)
It processes what it "sees" on an on-board computer, "so the job is largely done in terms of creating a map of what they saw that day by the end of the day," said Burzynski.
In other words, it won't take long to find out if the submarine's four-week search is successful.
"You won't have to wait weeks and months" to hear if anything has been found, said Burzynski. "This will be within days."
Planes built to intercept Soviet bombers
The Avro Arrow was the first and only supersonic interceptor built by the Canadian military, developed in the mid-1950s to respond to Soviet bombers targeting North America's Arctic.
In 1959, the program was abruptly cancelled and all materials related to it were destroyed.
The Avro Arrow was built to intercept Soviet bombers that might have entered North American airspace over the North Pole during the Cold War - until the Arrow program was abruptly scrapped in 1959. (Avro Museum)
The Avro Arrow models, scaled at one-eighth the size of the actual plane, are thought to have been launched over the lake in the mid-50s.
If recovered, the models will find homes at the Canada Aviation and Space Museum in Ottawa and the National Air Force Museum of Canada in Trenton, Ont. ||||| The search to find nine missing Avro Arrow prototypes, which were launched over Lake Ontario in the early 1950s, gets underway Friday.
An autonomous underwater vehicle (AUV) will begin to explore the waters off of Point Petre in Prince Edward County, an area thought to contain missing Avro Arrow test models.
WATCH: Search for lost Avro Arrow models in Lake Ontario begins
The expedition dubbed Raise the Arrow is a search-and-recovery project in connection to celebrating Canada’s 150th anniversary and is a collaborative effort with a handful of Canadian mining companies.
READ MORE: 55 years later, biggest question surrounding Avro Arrow remains “what if?”
“Today’s launch of the search marks an important milestone in bringing back a lost piece of Canadian history to the public,” John Burzynski, CEO of Osisko Mining and leader of the expedition, said in a statement. “The Arrow was meant to be the future of aviation – by finding and retrieving these marvelous examples of Canadian advanced technological design, this project is a proud reminder of what we as Canadians have done, and what we Canadians can do.”
The test models used in the early ‘50s were about an eighth of the size of the full CF-105 Arrow, and have been lost ever since. On March 25, 1958, the Avro Arrow made its first test flight. The program was scrapped a few months later. The CF-105 was originally designed as a long-range interceptor, meant to meet and destroy Soviet bombers.
READ MORE: Avro Arrow replica travels the streets of Toronto and Mississauga
If the expedition is successful and the test models are recovered, the prototypes will be housed at the Canada Aviation and Space Museum in Ottawa and the National Air Force Museum of Canada in Trenton, Ontario.
–With a file from Elton Hobson. |||||
Jennifer Cheng, The Canadian Press
A mission to find nine models of the Avro Arrow -- an advanced Canadian jet fighter that was controversially cancelled in 1959 -- began Friday with a submarine scouring the waters of Lake Ontario in search of the free-flight prototypes.
The models were launched from a military base in the 1950s as part of the development of the Avro Arrow, the first and only supersonic interceptor built by the Canadian military in the 1950s to counter potential Soviet bomber attacks in North America's Arctic.
If the models are recovered, they will find new homes at the Canada Aviation and Space Museum in Ottawa and the National Air Force Museum of Canada in Trenton, Ont.
The expedition, dubbed Raise the Arrow, is being led by John Burzynski, head of OEX Recovery Group Inc., which created the search-and-recovery project as part of Canada 150 celebrations and to coincide with next year's 60th anniversary of Avro Arrow's first test flight.
A programmable submarine supplied by Kraken Sonar Inc. spent eight hours Friday surveying an area just off Point Petre in Ontario's Prince Edward County where it's believed the missing free-flight prototypes were launched from a military base in the 1950s.
Burzynski said he came up with the project after following news reports of Kraken's involvement in recovering one of the ships belonging to the Franklin Expedition of 1845.
David Shea, Kraken's vice-president of engineering, was part of the five-person crew, following the submarine on a boat to make sure no one navigated over it.
The submarine is equipped with a military-grade sonar, which records acoustic data at a range of 300 metres and turns it into a high-resolution acoustic image, Shea told The Canadian Press in an interview from the boat on Friday.
They have 64 square kilometres to cover and Burzynski said it's likely the models will be among a lot of debris, which could include shipwrecks from the 1700s and 1800s and two planes that crashed in 1945 and 1960.
The search is expected to take two weeks, but could be extended to a month due to weather or other factors.
If the models are located, project archaeologist Scarlett Janusas said she will send some divers down to check on the integrity of the prototypes.
"I hope that they will be in one piece, but it's unlikely," she said while on site at Point Petre.
"We have to make sure that the structures are totally supported as we are bringing them out of the water, so they don't collapse on themselves," Janusas said.
She added that they will keep the models submerged until they first remove the biomass, which includes organic material and zebra mussels, so they can actually see the surface of the prototypes.
"It doesn't take much time for zebra mussels to take over something and obscure its appearance to the point that it looks like a rock," she said, noting it helps that they know the exact dimensions of the models, which are an eighth of the size of the full CF-105 Arrow.
Richard Mayne, director of Royal Canadian Air Force History and Heritage, which provided research for the project, says the Arrow left many Canadians with a sense of "what if" when the all-Canadian aircraft program was shut down by the federal government.
"Would Canada still be competing in modern fighter design of our own aircraft today?" Mayne said. "We were part of an elite club of nations that were building top-of-the-line fighters."
The Canada Aviation and Space Museum in Ottawa already houses a nose section and two wingtips, but much of the Avro Arrow didn't survive.
"The Avro Arrow is a reminder of what Canadians are capable of building," Burzynski said. | – When Canada suddenly ended the Avro Arrow program in 1959, it left the country with a lingering "what if" question, the director of Royal Canadian Air Force History and Heritage tells the Canadian Press: "Would Canada still be competing in modern fighter design of our own aircraft today?" The Avro Arrow was the only supersonic interceptor jet ever designed and built in Canada, the BBC reports. According to CBC, it was meant to respond to Soviet bombers in the Arctic during the Cold War. When the program was canceled—largely over cost—many of its engineers fled Canada to work at Lockheed, Boeing, NASA, and others in the US and UK. "It tugs at the Canadian psyche of what could have been in Canada," mining CEO John Burzynski tells the BBC. Burzynski is leading an effort to reclaim a piece of Canadian military history. When the Avro Arrow program was ended, pretty much everything was destroyed. But it's believed nine missing one-eighth-sized Arrow models launched over Lake Ontario in the 1950s to test the jet's flight design are still somewhere at the bottom of the lake. On Friday, an underwater vehicle equipped with military-grade sonar was deployed to find the missing Avro Arrow models, which would get new, drier homes in museums. "By finding and retrieving these marvelous examples of Canadian advanced technological design, this project is a proud reminder of what we as Canadians have done, and what we Canadians can do," the Global News quotes Burzynski as saying. (The search is on for Caligula's 2,000-year-old orgy boat.) |
there are many systems in nature and society that can be modelled by classical complex networks and explained by statistical physics.@xcite recently , the quantum world has opened up new perspectives in the field of complex networks .
@xcite for example , energy , charge , or information transfer are important phenomena in physical and biological systems taking place at scales ranging from atoms to large macro - molecular structures , and the idea has been put forward that quantum mechanics might have a positive effect on the efficiency of energy or charge transport in such systems . charge transport through dna @xcite and energy transfer in photosynthetic structures @xcite are good examples in this context . in fact , the most important effect of quantum mechanics in biological systems to date has been seen in the fenna - matthews - olson ( fmo ) complexes @xcite , observed by experimentally via ultrafast spectroscopy @xcite , where there is an ultrahigh efficient excitation energy transport ( eet ) in light - harvesting complexes.@xcite this can be modeled by quantum walks , @xcite or the lindblad formalism.@xcite simulated artificial complex networks based on biological systems have the potential to be used in future quantum informational and computational technologies such as secure information transfer between two particles in an entangled quantum - cryptography,@xcite teleportation in a quantum communication protocol,@xcite artificial photosynthesis systems ( or solar cells ) to save energy , and quantum neural networks@xcite for advanced technologies based on artificial intelligence .
the influence of edge deletion in networks for quantum state @xcite and energy transfer @xcite has been studied ; however , the influence of edge perturbation and deletion on the destructive interference of transition amplitudes in a network @xcite remains unexplored . in this paper
we consider this problem in a fully connected network and show how the energy can be transferred in the network via deletion of a single edge .
we analyze quantum energy transport in a simple model of a complete network of two - state nodes .
in particular , we demonstrate how energy transfer in such a network , which is inhibited by localization due to destructive interference , can be enhanced by breaking the symmetry between the nodes , or introducing disorder in the coupling between the network nodes .
our work is relevant from the point of view of building an artificial network for high efficient energy transfer to simulate systems such as fmo complexes in photosynthetic structures .
the paper is organized as follows . in sec .
[ eet ] , we describe the model hamiltonian of the network and introduce the method of calculating excitation energy transport , employing the lindblad formulation . in sec .
[ fcn ] we investigate eet in a fully connected network and discuss the negative effect of localization in this case . in sec .
[ edge - deletion ] we study the influence of single edge deletions in the network on the efficiency of eet .
we then investigate the influence of dephasing on eet in sec .
[ dephasing ] , by considering edge - deletions . in sec .
[ saturation ] we examine how the rate of energy transport can be optimized in the network . finally , in sec .
[ off - diagonaldisorder ] we discuss the role of off - diagonal disorder in the coupling constants between the network nodes in enhancing the efficiency .
section [ conclusion ] presents our summary and conclusions .
consider a graph @xmath1 ( i.e. a complex network ) as a pair of sets @xmath2 , where @xmath3 is a set of _ vertices _ or _ nodes _ of the graph and @xmath4 is a set of _ edges _ or _ links _
@xmath5 ( @xmath6 ) connecting the vertices @xmath7 and @xmath8 ( @xmath9 ) . an undirected graph is completely defined by its adjacency matrix @xmath10 , defined as : @xmath11 a _
complete @xmath12-graph _
( i.e. a fully connected network ) is a graph with @xmath13 edges where @xmath14 for the all pairs of nodes@xcite . consider a network , consisting of @xmath12 nodes , in which each node is a two - state object such as a molecule or a qubit , with a ground and an excited state .
we assume that the nodes interact with each other through direct hopping .
when hopping between two molecules is allowed , a link is drawn between them .
whenever an excitation is inserted at one node , it can then be transfered throughout the network by hopping due to the interaction between the linked nodes .
here we consider quantum energy transport in a network that can be modelled by the following tight - binding hamiltonian @xcite : @xmath15 where @xmath16 is the @xmath17-th site in which the excitation exists , @xmath18 denotes the excitation energy at site @xmath17 , and @xmath19 is the hopping integral between the two sites @xmath17 and @xmath20 .
we set @xmath21 when the nodes @xmath17 and @xmath20 are connected and @xmath22 if they are disconnected , and we choose @xmath23 so that all the energies are in units of @xmath24 .
possible decay events of the exciton to the ground state are neglected here .
to study dissipationless quantum excitation energy transport ( eet ) in the network , we use the evolution of the master equation in the markovian approximation as follows @xcite : @xmath25+l_{\rm{sink}}\rho , \label{master}\ ] ] in which @xmath26 is the density matrix .
@xmath27 is the _ sink _ term that expresses the irreversible transfer of energy from a given node of the network into a sink , and it is defined as : @xmath28,\ ] ] where the curly brackets denote the anticommutator , and @xmath29 is the absorption rate of the sink which is set to @xmath30 in all of the calculations in this paper .
the quantities @xmath31 ( @xmath32 ) are the creation ( annihilation ) operators at the site connecting site to the sink , and @xmath33 ( @xmath34 ) are the creation ( annihilation ) operators at the sink .
once an excitation is initially injected to the initial @xmath7-th site , we have @xmath35 . in order to measure eet from the initial site to the sink
, we integrate the master equation ( [ master ] ) and calculate the population of the sink @xmath36 at time @xmath37 .
the population of each node is @xmath38 .
another quantity of interest is the _ system efficiency _ which is defined as the long term sink population : @xmath39 and determines the fraction of excitation energy transferred into the sink in the long time limit .
our calculations are done using the python package qutip @xcite for numerical integration of the lindblad master equation ( [ master ] ) , and all energies , time scales , and rates are expressed in the units of on - site exception energies @xmath40 , and since we assume that the network iconsists of the identical units , we set @xmath41 for all @xmath17 .
we first consider eet in a fully connected network . in fig .
[ fcn](a ) we show a fully connected six - site network ( fcn ) .
the sink is connected to the node @xmath42 and the dissipationless excitation is injected to the node @xmath43 .
figure [ fcn](b ) shows the time dependence of the population of the nodes and the sink , calculated using numerical integration of eq .
( [ master ] ) .
it can be seen that the system efficiency ( sink population ) tends to @xmath44 , while most of injected energy ( @xmath45 ) remains inside the network , mostly on the first node ( @xmath46 of energy remains in node @xmath43 and @xmath47 is shared equally among the nodes @xmath48 and @xmath49 ) .
this result is a manifestation of the localization of single particle states within a fully connected network as already pointed out in ref . .
the reason for localization is the existence of destructive interference of transition amplitudes inside the network . to explicitly show this , we expand the initial state @xmath50 in terms of the orthonormal eigenstates of the tight - binding hamiltonian ( [ tbh ] ) , resulting in : @xmath51 eq .
( [ fcn - exp ] ) clearly shows that in the four out of six terms in the expansion of the initial state , the sixth node ( which connects the network to the sink ) has no contribution , and hence most of the injected energy can not reach this site and be transferred to the the sink . for visualization of the energy localization , the long time limit of the density matrix of the network
is illustrated in fig .
[ fcn](c ) , where the block diagonalization of the stationary density matrix is an indication of energy localization in the network . to investigate the effect of symmetry on the energy localization ,
we calculate the system efficiency when the hopping integral between the nodes @xmath43 and @xmath42 varies , while the rest of hopping integrals @xmath19 ( @xmath52 ) remain equal to unity .
the result is displayed in fig .
[ pop - j16 ] and it shows that the system efficiency ( @xmath53 ) is highly sensitive to the value of @xmath54 . for @xmath55 , @xmath53 is minimized , but when the hopping integral between the two nodes @xmath43 and @xmath42 slightly deviates from the other ones , the system efficiency rapidly rises to unity .
this result shows that the state localization inside a fully connected network is highly sensitive to the symmetry of the hamiltonian and any asymmetry due to @xmath54 destroys the destructive interference loops and hence localization in the network .
the important conclusion here is that such a symmerry breaking dramatically increases the efficiency of eet .
figure [ pop - j16 ] also shows that introducing asymmetry into the other links slightly increases the system efficiency , but does not promote the system to become a perfect transmitter . and @xmath56 ( @xmath57 ) .
it can be seen that the hopping rate @xmath54 connecting the insertion point and the sink has the strongest influence on the efficiency . ]
, in the case of deletion of edges between the nodes ( a ) @xmath58 ; ( b ) @xmath59 and ( c ) @xmath60 .
the dotted lines in the left panels denote the edges deleted .
as can be seen in case ( c ) , localization is absent in the network and therefore the eet efficiency to the sink becomes unity.,title="fig : " ] , in the case of deletion of edges between the nodes ( a ) @xmath58 ; ( b ) @xmath59 and ( c ) @xmath60 .
the dotted lines in the left panels denote the edges deleted .
as can be seen in case ( c ) , localization is absent in the network and therefore the eet efficiency to the sink becomes unity.,title="fig : " ] , in the case of deletion of edges between the nodes ( a ) @xmath58 ; ( b ) @xmath59 and ( c ) @xmath60 .
the dotted lines in the left panels denote the edges deleted .
as can be seen in case ( c ) , localization is absent in the network and therefore the eet efficiency to the sink becomes unity.,title="fig : " ] , in the case of deletion of edges between the nodes ( a ) @xmath58 ; ( b ) @xmath59 and ( c ) @xmath60 .
the dotted lines in the left panels denote the edges deleted .
as can be seen in case ( c ) , localization is absent in the network and therefore the eet efficiency to the sink becomes unity.,title="fig : " ] , in the case of deletion of edges between the nodes ( a ) @xmath58 ; ( b ) @xmath59 and ( c ) @xmath60 .
the dotted lines in the left panels denote the edges deleted .
as can be seen in case ( c ) , localization is absent in the network and therefore the eet efficiency to the sink becomes unity.,title="fig : " ] , in the case of deletion of edges between the nodes ( a ) @xmath58 ; ( b ) @xmath59 and ( c ) @xmath60 .
the dotted lines in the left panels denote the edges deleted .
as can be seen in case ( c ) , localization is absent in the network and therefore the eet efficiency to the sink becomes unity.,title="fig : " ] in the previous section we demonstrated that even a small asymmetry in the hopping rates is able to destroy the state localization in a fully connected network , and hence it increases the energy transfer to the sink .
next we proceed to investigate the influence of a defect on energy transport . to this end
, we consider cutting one link between any two nodes .
deletion of an edge between the nodes means blocking the hopping of the excitation between them .
figure [ edge - delet1 ] illustrates the density matrices of the networks with deletion of the links between the nodes @xmath58 ( fig .
[ edge - delet1](a ) ) , @xmath59 ( fig .
[ edge - delet1](b ) ) and @xmath60 ( fig .
[ edge - delet1](c ) ) .
it can be seen from this figure that only in the case of deletion of the link between the nodes @xmath43 and @xmath42 , the localization vanishes and the injected energy gets completely transferred into the sink . preventing hopping between the nodes @xmath58 and @xmath61 results in block diagonalization of the steady density matrix and hence localization inside the network is preserved .
this can be verified by expansion of the initial state in terms of the eigenstates of the hamiltonian in eq.([tbh ] ) , which results in the following expression : @xmath62 when the link between nodes @xmath43 and @xmath63 is deleted , and @xmath64 when the the link between nodes @xmath63 and @xmath65 is deleted .
finally , @xmath66 in the case of cutting the link between nodes @xmath43 and @xmath42 .
equations ( [ 12-delet ] ) and ( [ 23-delet ] ) explicitly show the vanishing contribution of the node @xmath42 to some of the terms in the expansion , while eq .
( [ 16-delet ] ) indicates that node @xmath42 contributes to all the components of the initial wave packet and in this case all the energy can be transmitted to the sink through this node .
we also checked that edge deletion between all the other nodes preserves localization in the resulting network .
figure [ edge - delet2 ] represents the block diagonalized structure of the stationary density matrices and the existence of localized states for some of these cases .
( dashed - dotted line ) , @xmath67 ( dashed line ) and @xmath68 ( dotted line ) , for ( a ) a fully connected network , and networks with deletion of the edges ( b ) @xmath69 , ( c ) @xmath70 and ( d ) @xmath71 .
it can be seen that in the cases with localization , the influence of noise is constructive and reduces the saturation time , while for the case without localization ( i.e. panel ( b ) ) noise increases the saturation time .
thus noise has a constructive influence on the cases with localization.,title="fig : " ] ( dashed - dotted line ) , @xmath67 ( dashed line ) and @xmath68 ( dotted line ) , for ( a ) a fully connected network , and networks with deletion of the edges ( b ) @xmath69 , ( c ) @xmath70 and ( d ) @xmath71 .
it can be seen that in the cases with localization , the influence of noise is constructive and reduces the saturation time , while for the case without localization ( i.e. panel ( b ) ) noise increases the saturation time .
thus noise has a constructive influence on the cases with localization.,title="fig : " ] + ( dashed - dotted line ) , @xmath67 ( dashed line ) and @xmath68 ( dotted line ) , for ( a ) a fully connected network , and networks with deletion of the edges ( b ) @xmath69 , ( c ) @xmath70 and ( d ) @xmath71 .
it can be seen that in the cases with localization , the influence of noise is constructive and reduces the saturation time , while for the case without localization ( i.e. panel ( b ) ) noise increases the saturation time .
thus noise has a constructive influence on the cases with localization.,title="fig : " ] ( dashed - dotted line ) , @xmath67 ( dashed line ) and @xmath68 ( dotted line ) , for ( a ) a fully connected network , and networks with deletion of the edges ( b ) @xmath69 , ( c ) @xmath70 and ( d ) @xmath71 .
it can be seen that in the cases with localization , the influence of noise is constructive and reduces the saturation time , while for the case without localization ( i.e. panel ( b ) ) noise increases the saturation time .
thus noise has a constructive influence on the cases with localization.,title="fig : " ]
next we investigate the influence of a noisy environment on quantum energy transport in networks . in most practical cases
the networks are open @xcite and interact with the environment , which is expected to reduce quantum coherence and constructive interference .
dephasing effects can be incorporated in the master equation in the framework of the lindblad operators as follows @xcite : @xmath72 \label{dephase}\ ] ] where @xmath73 is the dephasing rate coefficient . adding eq .
( [ dephase ] ) to the master equation ( [ master ] ) and integrating this equation as before gives energy transfer in the presence of noise .
figure [ dephasing889 ] represents the time dependence of the sink population in the absence and presence of noise with different values of the dephacing rate coefficient .
the results show that in cases where the wave packet is partially localized in the network , such as in the fully connected ( fig .
[ dephasing889](a ) ) , @xmath70 edge deleted ( fig . [ dephasing889](c ) ) , and @xmath71 edge deleted ( fig . [ dephasing889](d ) ) networks , the system efficiency monotonically increases ( both in magnitude and speed ) as dephasing is increased .
therefore , in these networks the noise has a constructive influence on energy transport by reducing quantum coherence .
however , when the hopping between the initial node and the one connecting to the sink ( @xmath69 ) is blocked , the wave packet localization is already destroyed and in this case the noise slows down the speed of energy transfer to the sink as illustrated in fig . [ dephasing889](b ) .
the results presented here show that the link which connects the initial node to the final node plays a fundamental role in eet , and as fig .
[ pop - j16 ] shows , when @xmath54 is changed from @xmath74 to @xmath75 or from @xmath76 to @xmath77 , complete energy transfer is obtained .
an obvious question then concerns finding a value of @xmath78 which is optimal in the sense that the _ saturation time _
@xmath79 is minimized .
we define @xmath79 to be the time after which the injected energy is transferred to the sink in the absence of dephasing . in fig .
[ sat ] we show numerical results for @xmath79 when varying the hopping rate @xmath54 .
the nontrivial result here is that except for the peak caused by localization , the saturation time decreases with increasing @xmath54 attaining a minimum which is numerically determined to be @xmath80 . on the hopping rate @xmath54 .
the saturation time is minimized by @xmath80 . ]
in addition to edge deletion considered in the previous sections , it s also possible to introduce disorder explicitly into the hopping integral parameters between the network nodes . in such networks
it is expected that the efficiency is strongly affected .
we have studied this issue by introducing disorder to the couplings by changing @xmath19 to @xmath81 , where @xmath82 is a dimensionless random number with a uniform distribution in the interval @xmath83 $ ] . in fig .
7 we show numerical results for the efficiency parameter @xmath53 as a function of @xmath84 for two fully connected networks with @xmath85 and @xmath86 nodes .
as expected , even a relatively small amount of disorder significantly increases the efficiency in an fcn .
finally , we have also studied the efficiency of edge - deleted networks in the case of @xmath85 nodes with off - diagonal disorder and dissipation in the network , as given by the following term in the master equation : @xmath87 .
\label{dissipation}\ ] ] we have considered a large number of networks ( @xmath88 in total ) , ranging from the case where there are six connections between the nodes up to the fcn , with fixed @xmath89 for all sites , as a function of the disorder strength @xmath84 between @xmath90 . while the detailed dependence of @xmath91 on @xmath84 is complicated and depends on the topology of the network , we find that for networks for which @xmath92 is close to unity to start with , increasing @xmath84 does not have much effect , as expected . in some cases , however , there s a slight approximately linear _ decrease _ in the efficiency , up to about @xmath93 % from @xmath94 to @xmath95 . on the other hand , for networks where @xmath92 is low ( less than @xmath96 ) , there s an approximately linear increase in the efficiency up to about twice its value at zero disorder ( e.g. in the case of the fcn ) .
more detailed results of these studies will be published elsewhere .
in summary , we have demonstrated in this work that quantum transport of an energy excitation in a symmetric network of fully connected two - state objects , described by a time reversal symmetric hamiltonian , is highly inefficient . whenever an excitation is injected into a node which is not directly connected to the sink , a wave packet travelling through closed loop paths arrives in - phase to the initial position due to the time reversal symmetry , which leads to destructive interference of the transition amplitudes at the initial site .
the corresponding localization of the excitation energy wave packets inside the network is the reason for inefficiency of transport in a symmetric , fully connected network .
reducing the symmetry by eliminating hopping between nodes not directly connected to the sink preserves the localized states and hence does not significantly increase the system efficiency .
we show that an efficient way to improve the efficiency of energy transfer is to introduce asymmetry between the initial node and the one directly linked to the sink .
the rate of energy transfer can be minimized by a nontrivial value of the hopping rate @xmath54 .
we have also included dephasing to the network and shown , as expected , that the presence of a dephasing noise increases the system efficiency .
the same effect can be obtained by introducing off - diagonal disorder in the hopping integral parameters between the nodes .
finally , we note that we have also carried out similar calculations for the cases @xmath97 and @xmath98 to verify the conclusions presented here .
our results should be useful in designing quantum networks for novel applications .
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roman s. ingarden , a. kossakowski , and m. ohya , _ information dynamics and open systems : classical and quantum approach _ , springer science & business media ( 2013 ) . | we consider quantum excitation energy transport ( eet ) in a network of two - state nodes in the markovian approximation by employing the lindblad formulation . we find that eet from an initial site , where the excitation is inserted to the sink , is generally inefficient due to the inhibition of transport by localization of the excitation wave packet in a symmetric , fully - connected network .
we demonstrate that the eet efficiency can be significantly increased up to @xmath0 by perturbing hopping transport between the initial node and the one connected directly to the sink , while the rate of energy transport is highest at a finite value of the hopping parameter .
we also show that prohibiting hopping between the other nodes which are not directly linked to the sink does not improve the efficiency .
we show that external dephasing noise in the network plays a constructive role for eet in the presence of localization in the network , while in the absence of localization it reduces the efficiency of eet .
we also consider the influence of off - diagonal disorder in the hopping parameters of the network . |
angular cheilitis ( ac ) also known as angular stomatitis , perlche ( from the french term pourlcher ( to lick one 's lips ) ) is a relatively common lesion characterized by erythema , maceration , ulceration and crusting at the commissures of the mouth .
factors that create a chronic , conducive , moist environment for microbial growth at the oral commissures such as habitual lip licking , thumb sucking or biting the corners of the mouth and sagging of tissues at the angles of the mouth contribute to the development of ac .
iron and vitamin deficiencies , consumption of carbohydrate - rich diets , long - term drug therapy such as immunosuppressants and antibiotics , gastrointestinal disorders , immunodeficiency status such as human immunodeficiency virus ( hiv ) infection are a few among a plethora of factors that predispose to the lesion .
ac has been included in the classification and diagnostic criteria for oral lesions in hiv infection .
although ac may not be observed very frequently during hiv disease , it is somewhat strongly associated with hiv infection . despite ac being a part of numerous studies on oral manifestations / oral lesions of hiv infection ,
there are limited studies that probed exclusively into the infective cause of ac in the hiv seropositive individuals and compared the same with that of the hiv seronegative population .
this study was designed with the objective of investigating the infective etiology of ac in hiv seropositive patients and make comparisons with that of hiv seronegative patients .
parameters such as cd4 cell count and serum hemoglobin ( hb ) level were also taken into account to gather if low cd4 cell count or low serum hb level predisposed to the differences in the microbial flora of ac .
a total of 46 patients who participated in the study were examined clinically and microbiologically and were categorized into three groups .
the patients from this group were brought in from a hiv / aids research center in chennai , south india .
the seropositive status of hiv was confirmed by enzyme - linked immunosorbent assay ( elisa ) and western blot tests .
a seropositive western blot was defined by the presence of at least one band corresponding to gag , env and pol gene translates of hiv .
group 3 : acted as the control group and included 10 hiv seronegative patients with no clinical evidence of ac .
the diagnosis of ac in groups 1 and 2 was done by clinical examination and the diagnostic criterion of ac was taken as an eroded and/or erythematous nonvesicular lesion radiating from the angle of the mouth [ figure 1 ] .
the patients belonging to groups 2 and 3 were selected from those who visited a reputed dental college in chennai , south india , for routine dental treatment .
bilateral angular cheilitis swabs from oral commissures were obtained with a sterile cotton wool moistened with sterile distilled water .
the swabs were at once inoculated on to sabouraud 's dextrose agar ( sda ) supplemented with chloramphenicol , blood agar ( ba ) and macconkey 's agar ( mca ) plates and transferred for culture .
the microorganisms cultured in the study were -hemolytic streptococci , staphylococcus albus , staphylococcus aureus , candida species , klebsiella species and pseudomonas species .
sda supplemented with chloramphenicol was used for the culture of candida species , ba and mca for bacterial growth .
the inoculated sda was incubated at 37c for 48 h , whereas mac and ba were incubated for 18 h at 37c .
the presence or absence of bacteria and candida was confirmed by the growth of colonies on the respective agar plates [ figures 2 and 3 ] .
bacterial colonies of staphylococcus aureus had a characteristic oil - paint appearance on ba and small , pink , circular appearance on mca .
streptococcus formed small , circular , semitransparent colonies with a zone of clear hemolysis around them and fermented sugars like sorbitol , lactose , maltose , mannitol and trehalose with production of acid but no gas and biochemically were catalase negative .
candida showed characteristic creamy white colonies on sda which was further speciated by conventional biotyping .
biotyping is the identification of candida species based on their biochemical abilities to ferment and assimilate sugars , produce germ tubes and form chlamydospores .
candidal colonies on sabouraud 's dextrose agar aerobic colonies on macconkey 's and blood agar plates in addition , the hiv seropositive patients were serologically tested for cd4 cell counts and serum hb levels and hiv seronegative patients for serum hb levels .
the -hemolytic streptococcus was isolated from all the 46 patients of the study ( 100% ) , regardless of their hiv status / presence or absence of ac .
twenty - five percent of the patients showed mixed infection with staphylococcus albus and candida species .
mixed flora of staphylococcus aureus and candida species was seen in 5% of the patients [ graph 1 ] . among the nine hiv seropositive patients who had cd4 cell count 200 , staphylococcus albus was isolated from 56% and
one patient with cd4 cell count of 84 showed colonization of staphylococcus albus , staphylococcus aureus and candida species .
klebsiella species was isolated from a patient with cd4 cell count of 111 and pseudomonas species colonies was found in one with cd4 cell count of 132 . in patients with cd4 cell count of more than 200 , staphylococcus albus was isolated from 36% , staphylococcus aureus was isolated from only 9% , while candida species was isolated from 55% of them .
mixed infection of staphylococcus albus and candida species was found in 9% of the patients .
none of them showed mixed flora of staphylococcus aureus and candida species [ graph 2 ] .
staph albus : staphylococcus albus , staph aureus : staphylococcus aureus , hiv : human immunodeficiency virus comparative microbiology of angular cheilitis in nine hiv seropositive patients with cd4 200 and 11 hiv seropositive patients with cd4 > 200 .
staph albus : staphylococcus albus , staph aureus : staphylococcus aureus , cd4 : cd4 cell count , hiv : human immunodeficiency virus also from this group , in patients with hb less than 14 g / dl , staphylococcus albus was isolated from 43% , staphylococcus aureus from 29% and candida species from 64% of the patients .
mixed flora of staphylococcus albus and candida species was seen in 29% of the patients .
mixed flora of staphylococcus aureus and candida species was seen in 7% of the patients . in patients with hb more than 14
g / dl , staphylococcus albus was isolated from 33% , staphylococcus aureus from 17% and candida species from 67% of the patients .
mixed flora of staphylococcus albus and candida species was seen in 17% of the patients .
mixed flora of staphylococcus aureus and candida species was not observed in these patients [ graph 3 ] .
comparative microbiology of angular cheilitis in 14 hiv seropositive patients with hemoglobin 14 g / dl and six hiv seropositive patients with hemoglobin > 14 g / dl .
staph albus : staphylococcus albus , staph aureus : staphylococcus aureus , hb : hemoglobin , hiv : human immunodeficiency virus the male : female ratio of this group was 5:3 .
staphylococcus albus was isolated from 69% , staphylococcus aureus from 13% and candida species from 56% of the patients .
twenty - five percent of the patients showed mixed flora of staphylococcus albus and candida species .
none of the patients showed mixed flora with staphylococcus aureus and candida species . in this group , patients with hb less than 14 g / dl , staphylococcus albus was isolated from 70% , staphylococcus aureus from 20% and candida species from 60% of the patients .
mixed flora of staphylococcus albus and candida species were seen in 30% of the patients . in patients with hb more than 14
g / dl , staphylococcus albus was isolated from 50% and candida species was from 50% of the patients .
mixed flora of staphylococcus albus and candida species was seen in 17% of the patients [ graph 4 ] .
staph albus : staphylococcus albus , staph aureus : staphylococcus aureus , hiv : human immunodeficiency virus staphylococcus albus was isolated from 70% of the patients in this group .
no other microorganisms were isolated from the oral commissures of this group and hence there was no mixed flora found .
however , in those with hb less than 14 g / dl , staphylococcus albus was isolated from 71% of the patients ; while in patients with hb more than 14 g / dl , staphylococcus albus was isolated from 67% of the patients .
twenty - five percent of the patients showed mixed infection with staphylococcus albus and candida species .
mixed flora of staphylococcus aureus and candida species was seen in 5% of the patients [ graph 1 ] . among the nine hiv seropositive patients who had cd4 cell count 200
, staphylococcus albus was isolated from 56% and staphylococcus aureus was isolated from 45% of them .
one patient with cd4 cell count of 84 showed colonization of staphylococcus albus , staphylococcus aureus and candida species .
klebsiella species was isolated from a patient with cd4 cell count of 111 and pseudomonas species colonies was found in one with cd4 cell count of 132 . in patients with cd4 cell count of more than 200
, staphylococcus albus was isolated from 36% , staphylococcus aureus was isolated from only 9% , while candida species was isolated from 55% of them .
mixed infection of staphylococcus albus and candida species was found in 9% of the patients .
none of them showed mixed flora of staphylococcus aureus and candida species [ graph 2 ] .
staph albus : staphylococcus albus , staph aureus : staphylococcus aureus , hiv : human immunodeficiency virus comparative microbiology of angular cheilitis in nine hiv seropositive patients with cd4 200 and 11 hiv seropositive patients with cd4 > 200 .
staph albus : staphylococcus albus , staph aureus : staphylococcus aureus , cd4 : cd4 cell count , hiv : human immunodeficiency virus also from this group , in patients with hb less than 14 g / dl , staphylococcus albus was isolated from 43% , staphylococcus aureus from 29% and candida species from 64% of the patients .
mixed flora of staphylococcus albus and candida species was seen in 29% of the patients .
mixed flora of staphylococcus aureus and candida species was seen in 7% of the patients . in patients with hb more
than 14 g / dl , staphylococcus albus was isolated from 33% , staphylococcus aureus from 17% and candida species from 67% of the patients .
mixed flora of staphylococcus albus and candida species was seen in 17% of the patients .
mixed flora of staphylococcus aureus and candida species was not observed in these patients [ graph 3 ] .
comparative microbiology of angular cheilitis in 14 hiv seropositive patients with hemoglobin 14 g / dl and six hiv seropositive patients with hemoglobin > 14 g / dl .
staph albus : staphylococcus albus , staph aureus : staphylococcus aureus , hb : hemoglobin , hiv : human immunodeficiency virus
staphylococcus albus was isolated from 69% , staphylococcus aureus from 13% and candida species from 56% of the patients .
twenty - five percent of the patients showed mixed flora of staphylococcus albus and candida species .
none of the patients showed mixed flora with staphylococcus aureus and candida species . in this group , patients with hb less than 14 g / dl , staphylococcus albus was isolated from 70% , staphylococcus aureus from 20% and candida species from 60% of the patients .
mixed flora of staphylococcus albus and candida species were seen in 30% of the patients . in patients with hb more than 14
g / dl , staphylococcus albus was isolated from 50% and candida species was from 50% of the patients .
mixed flora of staphylococcus albus and candida species was seen in 17% of the patients [ graph 4 ] .
staph albus : staphylococcus albus , staph aureus : staphylococcus aureus , hiv : human immunodeficiency virus
no other microorganisms were isolated from the oral commissures of this group and hence there was no mixed flora found .
however , in those with hb less than 14 g / dl , staphylococcus albus was isolated from 71% of the patients ; while in patients with hb more than 14 g / dl , staphylococcus albus was isolated from 67% of the patients .
ac has been investigated predominantly in the western world , with a few exceptions in the asian continent . in hiv infection ,
the importance of oral lesions has been widely studied and all hiv seropositive patients are susceptible to oral lesions at some point of their illness .
oral lesions occur in about 64% cases of hiv / acquired immunodeficiency syndrome ( aids ) in india and have a prevalence of 56% in the west .
some opportunistic oral infections can not only be indicators of the onset of hiv infection and present as early clinical features , but also as progressive markers of hiv infection to full blown aids .
the most common hiv - related oral disorder reported so far is oral candidiasis which occurs in 17 - 43% cases with hiv infection and in more than 90% of cases with aids .
the classification and diagnostic criteria for oral lesions in hiv infection proposed in 1993 stated that ac can be associated with candida albicans and may be seen in dentate patients with hiv infection .
studies have shown that ac can be caused by candida albicans alone ( 20% ) , mixed infection with candida and staphylococcus aureus ( 60% ) and staphylococcus aureus alone ( 20% ) . from our present study we found that in hiv seropositive patients with ac ( group 1 ) candida albicans ( 65% ) and staphylococcus aureus ( 30% ) were more prevalent .
incidentally when the cd4 cell count dropped below 200 , there was an increase in the incidence of mixed flora of candida and staphylococcus aureus when compared to patients with cd4 cell count of higher than 200 .
those with hb value of less than 14 g / dl showed an increase in the candidal and staphylococcal colonization .
group 1 patients also had 24% less incidence of staphylococcus albus and 17% more incidence of staphylococcus aureus colonization when compared with that of group 2 population . on the other hand , in hiv seronegative patients with ac ( group 2 ) there was a prevalence of staphylococcus albus ( 86% ) in the lesions , followed by candida albicans ( 70% ) .
staphylococcus aureus was found only in 16% of the cases . also those with hb value of less than 14 g / dl showed an increase in the incidence of candida albicans and staphylococcus aureus when compared to patients with hb value of more than 14 g / dl . in group 3
patients , candida species and staphylococcus aureus were not isolated from the oral commissures regardless of their hb status .
this is concomitant with earlier studies which have suggested that the isolation of staphylococcus aureus and candida species from the oral commissures may be of pathogenic significance .
there was a general trend of increase in the incidence of candida albicans and staphylococcus aureus colonization in patients with hb value less of than 14 g / dl albeit the hiv status .
this suggests that a reduced hb level could predispose to candidal and pathogenic bacterial colonization in ac irrespective of the hiv status .
the data from our study points to a distinctive microbial flora in ac , which , in the hiv seropositive patients is probably influenced by their immunosuppression ( as ascertained by the cd4 cell count ) and hb level in both hiv seropositive and hiv seronegative population .
the clinical implication and objective of identifying the precise infective etiology through microbiological analyses would be to employ appropriate antimicrobial therapy tailored to its causative agent which would help in hastening the healing process .
angular stomatitic lesions that are refractory to treatment or chronically recurring in non - denture wearers should prompt evaluation for hiv infection or other immunocompromised conditions . from our study we conclude that there is a distinctive difference in the microbial flora of ac in hiv seropositive patients when compared with that in hiv seronegative population .
there have not been studies with similar designs from south india so far . however , to confirm these differences statistically , a study with a larger cohort and analysis of the colony forming units ( cfu ) need to be carried out . | objective : this study was designed to compare the microbiological features of angular cheilitis ( ac ) in human immunodeficiency virus ( hiv ) seropositive and hiv seronegative individuals , in a group of south indians.materials and methods : swabs from oral commissures of 46 patients were obtained and inoculated on to sabouraud 's dextrose agar ( sda ) supplemented with chloramphenicol , blood agar ( ba ) and macconkey 's agar ( mca ) plates and cultured .
-hemolytic streptococci , staphylococcus albus , staphylococcus aureus , candida species , klebsiella species and pseudomonas species were cultured .
candidal colonies were further speciated by the conventional biotyping technique.results:in ac of hiv seropositive patients candida albicans and staphylococcus aureus were more prevalent than that in hiv seronegative patients .
incidentally in patients with cd4 cell count less than 200 there was an increase in the incidence of candidal and staphylococcus aureus colonization when compared to patients with cd4 cell count higher than 200.conclusion:the present study suggests a definite difference in the microbial flora of ac in hiv seropositive patients than that of hiv seronegative population . |
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SANDVIKEN, Sweden — As tens of thousands of migrants run the gantlet of dangers to reach Europe, Natanael Haile, a refugee from Eritrea now living in Sweden, is struggling to get over his nightmarish journey.
He was kidnapped twice by desert gunmen, who extorted more than $20,000 from his family. He narrowly survived the sinking of a smugglers’ flimsy fishing boat off the Italian island of Lampedusa on Oct. 3, 2013, swimming through waters clogged with the bodies of more than 350 drowned passengers.
“When I think of the price that I and my family had to pay, it was definitely not worth it,” Mr. Haile, 28, said. “I went through hell.”
“I was not looking for heaven in Europe,” he added, “but it is not what you expect.”
Mr. Haile and other migrants who arrived on Lampedusa that day said they feel isolated in their new countries, find the local languages difficult, worry about jobs and have few family connections or friends beyond fellow migrants.
Even so, they had no intention of returning home, saying they believed they could make a new start. They included one migrant who was arrested last month in connection with a gang-rape investigation in Sweden.
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The 2013 sinking of the boat, packed with more than 500 migrants, was a signal moment in Europe’s migration crisis, a calamity that riveted the world’s attention on the mounting toll in the Mediterranean and that elicited promises of united action from European leaders.
Since then, Europe’s migrant crisis has only grown, and the harrowing but ultimately successful quest for new lives by Mr. Haile and other migrants on the boat helps explain why efforts to slow the tide of migrants to Europe have done little so far.
Over the weekend, Germany and Austria cleared the way for thousands of migrants hoping for more secure lives.
Mr. Haile and the others are a revealing representation of the hardships that migrants endure, and of the ways they nimbly outmaneuver slow-moving bureaucracies.
Some survivors burned their fingertips to avoid having their prints taken and registered in databases that would prevent them from reaching richer countries like Germany or Sweden, often their preferred destinations. If fingerprints are not taken, a migrant can move on and seek asylum elsewhere.
Now that their journeys are over, the survivors expressed disillusionment and disappointment about the countries in which they now live, though none could quite articulate what they had hoped to find in Europe.
Still, they gushed with gratitude for the money and help their host nations had provided.
Mr. Haile said he frequently received calls from friends and relatives in Eritrea who wanted to know if they should attempt the same risky journey that brought him to Europe.
He said he had given up trying to offer advice, even though only 26 of the 131 Eritreans with whom he set out to cross the Libyan desert and catch a boat to Italy survived.
“I know what I went through, but they won’t listen,” he said at the housing complex packed with migrants where he shares an apartment with two others who left Africa. “I didn’t listen, either, when people warned me about the dangers.”
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Would-be migrants, Mr. Haile said, do not want to know about the perils of his journey, but instead about his secondhand car, the government allowances he receives and his plans to find work as a welder once he finishes a two-year language course.
There is no point in telling them not to come, he said.
The struggles of adjusting to an unfamiliar land pale in comparison with the threat of death or persecution in places like Afghanistan, Syria or Eritrea, which has an isolated and repressive government.
Despite the dangers, the high walls, the barbed wire or other obstacles thrown in their paths, the migrants keep trying to reach Europe, lured by even the slimmest prospect of a new start.
“At least here we are not slaves and have a little hope for the future,” said Fanus Agby, 19, another survivor with Mr. Haile who made it to Sweden, where she hopes to become a nurse.
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Of the 155 migrants who survived the Lampedusa shipwreck, around 100 made it to Sweden. Because they first arrived in Italy, under European Union rules, they should have been fingerprinted and had their requests for asylum taken there. And they should have remained there while their applications were being processed.
The failure of governments, wary of an anti-immigrant backlash as right-wing parties gain support, to follow these rules has now moved to the center of disputes between European leaders over how to handle the migration crisis.
Migrants themselves have also undermined the rules. Ms. Agby, the 19-year-old Lampedusa shipwreck survivor who made it to Sweden, said she had been so desperate to avoid being forced to stay in Italy that she had burned a plastic bag and rubbed her fingers in the molten goo to make her fingerprints unreadable.
Only one survivor of the October crossing, a young man who asked to be identified only by his first name, Tadese, got stuck in Italy, where his fingerprints were taken after he was hospitalized because of his injuries. The 50 or so other survivors mostly ended up in Norway, Germany and Denmark.
Mr. Haile said he had nothing against Italy. But throughout his ordeal, it was the dream of reaching Scandinavia, famous among migrants for generous welfare and asylum policies, that kept him going.
“Italians are the nicest people,” Mr. Haile said, “but their system for refugees is terrible.”
It took seven months for the Swedish authorities to process and approve Mr. Haile’s application for asylum. But the procedure often takes only three months, far shorter than in Italy, where it can drag on for years, he said.
Mr. Haile said that he had originally planned to go to Norway, which has the highest cash benefits for refugees, but that he eventually traveled to Sweden because he had contacts here.
So that he could board a plane to Milan from Rome and on to Stockholm, he paid a smuggler in Italy 1,200 euros, or about $1,340, for a fake Italian passport.
“It looked really good, brand new,” he said.
His journey from Eritrea, which he fled to escape open-ended mandatory military service after serving four years in the army, began in 2008 and lasted five years, with long spells in Sudan, where he drove a taxi, and months in captivity with two different bands of kidnappers.
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Sweden, Mr. Haile said, is hardly paradise. He said that people in Sandviken, while rarely hostile, were cool and distant, and that they “only really talk when they are drunk.” He longs to see his son, who was born in Eritrea after he left.
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But in many ways, he has achieved the dream that is drawing so many people toward Europe today. He is a registered refugee, attends free language classes provided by the state and receives a monthly living allowance of more than $700.
Sweden’s minister in charge of immigration, Morgan Johansson, said his country remained committed to helping migrants, despite the rising popularity of the anti-immigration Sweden Democrats party, but he added that other countries needed to pull their weight.
“It cannot be only Sweden and Germany,” he said in an interview. “Everyone must share responsibility.”
Mr. Johansson said that he knew of no specific decision by Swedish immigration officials to accept many survivors of the Lampedusa tragedy of October 2013, but he added that Eritreans often qualified for asylum. Their country, he said, is “one of the world’s toughest dictatorships.”
Another survivor of that sinking who is now in Sweden, Tesfamichael Gazgel Hagos, said he had burned all his fingertips with a cigarette lighter to make sure he could make it to Sweden, which quickly approved his asylum request.
The ruse worked, but after buying a fake passport in Rome and traveling to Sweden, Mr. Hagos landed in deep trouble.
He was arrested in August in connection with the gang rape of a Swedish woman in the Ludvika apartment he shared with another Eritrean. He was not charged, was released after a week and denied any involvement in the crime.
Sweden, “is not what I expected,” said the thin 25-year-old in an interview a day after his release. “It is not as easy as I thought.”
Even while under investigation for a serious crime, he still receives a monthly allowance of 6,500 krona, about $770, and has resumed language classes, also provided by the state. He plans to get a job as a car mechanic.
The Ludvika rape case, along with the alleged murder by an Eritrean refugee of a mother and her son in the kitchenware section of an Ikea store in the nearby town of Vasteras, stirred public outrage and have been seized on by the Sweden Democrats to press for an end to the country’s welcoming policies toward asylum seekers.
“It makes no difference to me whether he nearly died in Lampedusa or not,” said Benny Rosengren, the head of the party in Ludvika.
The Swedish news media and national politicians “always want to find an excuse,” he added. “They present the refugees as victims, and then use people’s pity to excuse things like rape.”
Other survivors of the crossing have tried to keep their heads down and stay out of trouble.
Mohamed Kasim, a melancholy 40-year-old who now lives in Tommestrup, a Danish village south of Copenhagen, cycles to language classes in a nearby town every day, and he takes a train to the region’s only mosque for Friday Prayer. Otherwise, he stays home.
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Mr. Kasim said that he had a hard time making contact with locals, but that his spirits were lifted by the recent arrival of his wife from Eritrea. The Danish government pays his rent, as well as a living allowance. All the same, he said he advises friends not to risk following his example.
“I tell them, ‘No — 100 percent no,’ ” he said, “but nobody listens.”
Mr. Kasim, who is older than most of those who survived the sinking off Lampedusa in 2013, says he misses his home country and cannot forget the four hours he spent at sea, surrounded by bodies, after the boat sank. “I can’t swim, so just did this,” he said, waving his arms clumsily.
Samhar Adhanam, a 25-year-old living on a monthly government allowance of nearly $1,500 in Larvik, Norway, was in such bad condition when she was rescued at sea that she spent two weeks in a Sicilian hospital recovering from her injuries.
After obtaining a forged passport, she headed toward Norway by train, and spent much of the journey hiding in the restroom. After months in a reception center near the Arctic Circle, she received approval to stay in the country, and she moved south to Larvik.
“I never thought it would be like this,” Ms. Adhanam said. “Everything is so different.”
But as strange as the new country is, she said, “I can say I am happy because I am still alive.” ||||| Yafet and Segen had met nine years earlier at a neighborhood café in Asmara, the Eritrean capital. He was in 10th grade, she was a year behind him, the coffee shop was a popular hangout for their school friends. It was frowned on for girls and boys to socialize too much, so larger groups of teenagers would often get together to provide cover for a couple who were dating. That’s how Yafet and Segen met: They were accompanying two friends who were seeing each other secretly. And when those friends needed a little privacy, Yafet and Segen would fill the time by chatting with each other. Slowly, he started to fall for her. “When we started to talk… not actually in one day, but after months, I started to like so many things about her: The way she talked; the way she laughed; the way she smiled,” Yafet says. “I fell in love, and I asked her to start a relationship.”
Photographer Gianni Cipriano documented objects abandoned by refugees that made the arduous journey from North Africa to Sicily.
Yafet was born in 1987. He was the youngest of seven children; his father was a high school physics teacher and his mother taught typing; together they all lived in a four-bedroom house in an upscale district of Asmara. Back then, Eritrea was at the tail end of a 30-year war for independence from Ethiopia, and families like Yafet’s — middle class, educated — were poised to form the backbone of the new nation. Freedom came in 1993, but the optimism didn’t last. In 1998, a new conflict with Ethiopia escalated, and within two years 100,000 people were dead. President Isaias Afwerki came under scrutiny for his leadership: He responded by cracking down on dissent, banning the country’s privately-owned newspapers, and imprisoning anyone who opposed him. He has ruled ever since. Today, Eritrea is one of the world’s most repressive states: There are extensive reports of torture, forced labor, arbitrary arrests, incommunicado detention, extrajudicial killings, and disappearances. Its primary mechanism of control is national service: Citizens are conscripted for an indefinite period and forced to work in government enterprises for almost no pay. There are restrictions on freedom of expression, assembly, and religion. Even though he was just a young teen when it happened, the crackdown sticks with Yafet. And once his eyes were open, he couldn’t look away. “I used to ask my mom, ‘Mom, why?’” he says. “My mother told me to keep quiet, don’t talk like that outside. I’m in my country. I’m just asking what happened. Why can’t I say? Later, I saw what happened to the people who asked.” Today, more than 400,000 people — one in every 16 Eritreans — have fled the country.
By September 2007, he and Segen had been dating for two years. Like everyone else in the country, he reported for six months of military training after finishing 11th grade, before returning to high school. After graduating, and just a few days before he was to be officially drafted, he took Segen aside. He was leaving Eritrea, he said. Yafet and Segen She wasn’t happy. Not because she couldn’t see the oppression — she had dropped out of school herself after 10th grade to avoid national service. The fear was that they would never have a chance to build a future together. But they understood that staying didn’t give them that chance either. “We couldn’t imagine having any future there with the government. That’s why she accepted it. I promised not to forget her. She told me that she would pray for me… and that one day we would be together and have kids.”
The border between Eritrea and Sudan is a desert of cracked earth where temperatures soar into the 100s. The only distinguishable feature marking the boundary between the two countries is a low mountain ridge that cuts across the horizon. “Beyond the mountain is Sudan. In front of it is Eritrea,” Yafet says. Reaching it meant reaching freedom. After saying goodbye to Segen and his family, Yafet reported for duty at a military camp in the west of the country. He stayed there for three days while making final arrangements before heading into the desert with eight friends. He was 20 years old, and he knew he’d never be able to go home again. “I knew where the west was, and I knew if I went to the west [I would reach Sudan],” Yafet said. But it was a two-day walk from the camp to the border, and the government did not treat deserters kindly. There was no cover — no trees, no bushes — to obscure them from sight, so they travelled mostly at night. But even after dark the moon was so bright that they didn’t have much protection. So they devised a system. Each of them would take turns walking several hundred feet in front of the others: That way, if they came across a military patrol, only the scout would be captured, and the rest of the group would have a chance to escape. It wasn’t just the Eritrean patrols that were a threat, though. There was also a chance of running into criminals or security forces on the Sudanese side who would deliver them back to Eritrean authorities in exchange for money. After walking for two nights and a day in the desert, the group reached the mountain. On the other side, they found it difficult to find their way — nobody in the group spoke Arabic, just the main Eritrean language, Tigrinya, and a little English. Then they came into some luck: A friendly Sudanese man brought them to his house. “He gave us food, water, even milk. We were wearing military clothes. He brought us civilian clothes.” The man pointed the group in the direction of a nearby refugee camp. Yafet had made it. Now he could begin his new life.
“It was the worst place I have seen in my life. There was no food service. There were no houses… There were tents that were donated by UNHCR, but it wasn’t enough for the people. There was no clean water for the refugees, there were no medical services, there was one nurse and the refugees were maybe 2 or 3,000 at that time. If you had money you could pay for food, but there were people who didn’t have money. They were really in trouble.” Yafet was in Wad Sherife, a refugee camp about 10 miles from the border. It was against the law to leave, so three months later, he paid a smuggler $100 to take him to Khartoum, the capital of Sudan, where he could think about going further — to Europe or the U.S. But Khartoum itself was another horrible shock, an unforgiving and legally precarious place, where Yafet was constantly exposed to danger and abuse. At first he relied on the help of others: One relative in the United States sent him money, another who lived locally gave him shelter. He shared a small room with five other people — it was bare, hot, and didn’t even have beds — but still, Yafet was happy. It was the first time he could process being outside of Eritrea. “It was good for us. We had freedom. We felt that we could relax. We could speak about what we wished… things that we wouldn’t dare say in Eritrea. We discussed our country. We discussed our futures. They were the things that we hadn’t ever expressed.” Things got progressively worse, though. His support network faded, his money ran out. Most nights he scraped together enough to sleep in the underground hotels run out of people’s houses; sometimes he slept outside, mingling with other homeless people and keeping away from the police. Eventually, he found a job in a bakery: The owner gave him $3.50 a day in wages and let him sleep in the back of the store at night. It was a tiny bit of stability, but not enough to build a future. So, when Segen told Yafet that she was coming to Sudan in the summer of 2009, he was not happy. “I just told her to be a little patient, to wait for me to try something,” he says. “I didn’t want to bring her and see her be in trouble and I also didn’t want to be in more trouble.” Segen decided to come anyway. She didn’t have much money, but her cousin— a people smuggler — agreed to help her escape from Eritrea if she could find three friends to come with her who would pay.
Segen finally married Yafet in September 2010 — a church service, with about 30 people in attendance. “I was happy that day because I got my dream girl and it was my wedding day,” says Yafet. Things were looking up. They moved in together, and he had a new job marketing agricultural products online, with his own office, his own computer, and a salary of $500 per month. Finally being united, however, didn’t reduce the insecurity. They argued about whether to stay or try to get out. Segen’s family was encouraging her to flee Africa altogether, either to Israel — by crossing the Sinai desert — or to Europe, by boat across the Mediterranean. Both options were dangerous. “I didn’t want to put our lives at risk in order to get a better life,” Yafet says. “That’s why I wanted to let her know that if we found a better way, a safe way, if we get resettlement or a visa and could leave by plane, that’s ok, but, no, we don’t have to risk our lives.” Then Yafet’s company closed, and he lost his job. Their first daughter, Shalom, was born a month later, on August 16, 2011. He’d work wherever, whatever way he could: cleaning houses, manual labor, restaurants, anything. Then, a few months after she gave birth to Shalom, Segen got pregnant again. Their second daughter, Abigail, was born on October 29, 2012. Nothing was steady, and Segen was more unsettled than ever. Finding a way to leave became the main topic of discussion. It was too much. “She wasn’t able to get sleep. She wasn’t able to eat food. She wasn’t able to care for the children… She used to cry without any cause. She used to get angry about small things. She was not at peace. I tried to make her feel free, to make her relax. She got worse and worse.” Then, one day, she told him she couldn’t wait anymore. The couple weighed their options. In the end they agreed: Segen would cross the desert to Libya and get on one of the boats smuggling people across the Mediterranean to Italy. Once there, she would head for Norway, which has one of the fastest asylum and family reunification processes in Europe. Yafet would follow. Initially, he wanted both of their daughters to stay with him in Khartoum. But Segen thought that having Abigail with her would help keep them both safe from abuse during the trip and maybe even win some preferential treatment, like receiving extra food and water — things which could make a big difference during the long desert crossing that lay ahead. Yafet conceded. | – When a rickety fishing boat smuggling more than 500 passengers across the Mediterranean capsized on Oct. 3, 2015, the world took notice. More than 350 people, many refugees from Eritrea, drowned, and European leaders promised action, reports the New York Times. But when 243 passengers, again largely refugees from Eritrea, were supposed to be aboard an Italy-bound boat and disappeared without a trace less than a year later, on June 28, 2014, the press, and the world, turned a blind eye, reports Eric Reidy on Medium. Reidy tries to follow the story of one Eritrean woman named Segen who was supposed to be on the "ghost boat," which was to depart from Libya. She survived the perilous journey across the country with her baby Abigail in her arms; the last time her husband spoke with her was the day she was supposed to board the boat—if the refugees ever boarded it. Reidy notes that "?experts say there would almost certainly be evidence" of a maritime disaster so large, and there are no records of such a boat arriving in Europe, sinking, or being aided. One activist heard word that the 243 were potentially being held in a Tunisian jail; "her findings were inconclusive." Says Segen's husband, who stayed in neighboring Sudan with their now 4-year-old girl Shalom: "If you remember Charlie Hebdo in Paris ... The world stopped for 14 people, but white people, Europeans," he says. "But in our case, nothing…. Because we are black? I don’t know why. It’s really hard. What can I say? We are human." Read Reidy's full account here. |
2 i despite the lack of direct experimental evidence for supersymmetry ( susy ) , the concept of symmetry between bosons and fermions has so many attractive features that the supersymmetric extension of the standard model is widely considered as a most natural scenario .
it protects the electroweak scale from destabilizing divergences , leads to the unification of gauge couplings , accommodates a large top quark mass , provides a natural candidate for dark matter , and decouples from precision measurements .
exact supersymmetry is a fully predictive framework : to each known particle it predicts the existence of its superpartner which differs in the spin quantum number by 1/2 , and fixes their couplings without introducing new parameters .
thus the minimal supersymmetric extension of the standard model ( mssm ) encompasses spin 1/2 partners of the gauge and higgs bosons , called gauginos and higgsinos , and spin 0 companions of leptons and quarks , called sleptons and squarks .
if realized in nature , supersymmetry ( susy ) must be a broken symmetry since until now none of the superpartners have been found .
the construction of a viable mechanism of susy breaking , however , is a difficult issue .
it is impossible to construct a realistic breaking scenario with the particle content of the mssm @xcite .
therefore the origin of susy breaking is usually assumed to take place in a `` hidden sector '' of particles which have no direct couplings to the mssm particles and the supersymmetry breaking is `` mediated '' from the hidden to the visible sector .
this opens up a variety of possible scenarios of susy breaking and its mediation , and in fact many models have been proposed : gravity - mediated , gauge - mediated , anomaly - mediated , gaugino - mediated etc .
each model is characterized by a few parameters ( usually defined at a high scale ) and leads to different phenomenological consequences . with all the different susy models proposed in the past ,
the best is to keep an open mind and parameterize the breaking of susy by the most general explicit breaking terms in the lagrangian .
the structure of the breaking terms is constrained by the gauge symmetry and the requirement of stabilization against radiative corrections from higher scales .
this leads to a set of soft - breaking terms @xcite , which include + ( i ) gaugino mass terms for bino @xmath1 , wino @xmath2 @xmath313 ] and gluino @xmath4 @xmath518 ] m_1 + m_2 ^i ^i + m_3 ^i ^i , ( ii ) trilinear ( @xmath6 ) and bilinear ( @xmath7 ) scalar couplings ( generation indices are understood ) a_u h_2 ^c + a_d h_1 ^c + a_l h_1 ^c - b h_1 h_2 ( iii ) and squark and slepton mass terms m_^2 [ ^*_l_l + ^*_l_l ] + m_^2 ^*_r _
r + m_^2 ^*_r _
r+ where the ellipses stand for the soft mass terms for sleptons and higgs bosons ( tilde denotes the superpartner ) .
the above parameters can be complex with nontrivial cp violating phases @xcite .
the stability of quantum corrections implies that at least some of the superpartners should be relatively light , with masses around 1 tev , and thus within the reach of present or next generation of high - energy colliders . as a consequence of the most general soft - breaking terms ,
a large number of parameters is introduced .
the unconstrained low - energy mssm has some 100 parameters resulting in a rich spectroscopy of states and complex phenomenology of their interactions .
one should realize , that the low - energy parameters are of two distinct categories .
the first one includes all the gauge and yukawa couplings and the higgsino mass parameter @xmath8 .
they are related by exact supersymmetry which is crucial for the cancellation of quadratic divergences .
for example , at tree - level the @xmath9 , @xmath10 gauge and @xmath11 yukawa couplings have to be equal .
the relations among these parameters ( with calculable radiative corrections ) have to be confirmed experimentally ; if not the supersymmetry is excluded .
the second category encompasses all soft - supersymmetry breaking parameters : higgsino , gaugino and sfermion masses and mixing , and the trilinear couplings .
if supersymmetry is detected at a future collider it will be a matter of days to discover all kinetically accessible supersymmetric particles .
however , it will be an enormous task to investigate the masses , couplings and quantum numbers of the superpartners and many measurements and considerable ingenuity will be needed to reconstruct a complete low - energy theory .
the experimental program to search for and explore susy at present and future colliders has to include the following points : + ( a ) discover supersymmetric particles and measure their quantum numbers to prove + that they are _ the _ superpartners of standard particles , + ( b ) measure their masses , mixing angles and couplings , + ( c ) determine the low - energy lagrangian parameters , + ( d ) verify the relations among them in order to distinguish between various susy + breaking models .
it is important to realize that all low - energy susy parameters should be measured independently of any theoretical assumptions . in this respect
the concept of a high - energy @xmath0 linear collider @xcite is of particular interest since it opens up a possibility of precision measurements of supersymmetric particle properties .
an intense activity during last few years on @xmath0 collider physics has convincingly demonstrated the advantages and benefits of such a machine and its complementarity to the large hadron collider ( lhc ) .
many studies have shown that the lhc can cover a mass range for susy particles up to @xmath12 2 tev , in particular for squarks and gluinos @xcite .
early indication of susy can be provided by an excess in @xmath13 , an example is shown in fig.[fig : lhc ] , where @xmath14 is due to the stable lightest susy particles ( lsp ) escaping detection , and @xmath15 are transverse momenta of jets .
sparticles from squark and gluino decays can be accessed if the susy decays are distinctive .
the problem however is that many different sparticles will be accessed at once with the heavier ones cascading into the lighter which will in turn cascade further leading to a complicated picture .
simulations for the extraction of parameters have been attempted for the lhc and demonstrated that some of them can be extracted with a good precision . identifying particular decay channels and measuring the endpoints , for example in the dilepton invariant mass as shown in fig.[fig : lhc ] , the mass differences of susy particles can be determined very precisely .
if enough channels are identified and measured , the masses can be determined without any model assumptions . with a large amount of information available from the production of squarks and gluinos and their main decay products ,
theoretical interpretation can be possible in favorable models .
[ fig : lhc ] but if all proposed theoretical models of the susy breaking turn out to be wrong , the concurrent running of an @xmath0 lc will be very much welcome .
it will provide information complementary to that from the lhc .
thanks to + @xmath16 clean final state environment , + @xmath16 tunable energy , + @xmath16 polarized incoming beams , + @xmath16 and a possibility of additional modes : @xmath17 , @xmath18 and @xmath19 + precise determination of masses , couplings , quantum numbers , mixing angles and cp phases will be possible at @xmath0 colliders .
as i will illustrate with some examples below , this will allow us a model independent reconstruction of the low - energy susy parameters to be performed and , hopefully , connect the low - scale phenomenology with the high - scale physics @xcite .
in contrast to many earlier analyzes , we will not elaborate on global fits but rather we will discuss attempts at `` measuring '' the fundamental lagrangian parameters . generically such attempts are performed in two steps @xcite + @xmath20 : from the observed quantities : cross sections , asymmetries etc . determine the + physical parameters : the masses , mixing and couplings of sparticles , + @xmath7 : from the physical parameters extract the lagrangian parameters : @xmath21 , @xmath8 , @xmath22 , + @xmath23 , @xmath24 etc . to deal with so many parameters ,
a clear strategy is needed .
an attractive possibility would be to + @xmath16 start with charginos which depend only on @xmath25 , @xmath8 , @xmath22 , + @xmath16 add neutralinos which depend in addition on @xmath26 , + @xmath16 include sleptons which bring in @xmath27 , @xmath28 , + @xmath16 and finally squarks and gluinos to determine @xmath29 , @xmath30 and @xmath31 + to reconstruct at tree level the basic structure of susy lagrangian . in reality it might be difficult to separate a specific sector ( _ e.g. _ sleptons enter via t - channel in the chargino production processes ) , many production channels can simultaneously be open , and susy constitutes an important background to susy processes .
in addition sizable loop corrections will mix all sectors .
precision measurements will require loop corrections to the masses and mixing angles , the finite decay width effects and loop corrections to the production and decay processes to be included for final global analyzes of all data .
some one - loop results are already available : for the current status we refer to @xcite . the mass matrix of the wino and charged higgsino , after the gauge symmetry breaking , is nondiagonal @xmath32 it can be diagonalized by two unitary matrices acting on left- and right - chiral states @xmath33 with @xmath34 , @xmath35 , which involve two mixing angles @xmath36 and three cp phases @xmath37 and @xmath38 the mass eigenstates , called charginos , are mixtures of wino and higgsino with the masses and mixing angles given by @xmath39 \label{massch}\\ & & \cos 2\phi_{l , r}=-\left[m_2 ^ 2-|\mu|^2\mp 2m^2_w\cos 2\beta\right]/ { \delta_c}\label{mixch}\end{aligned}\ ] ] where @xmath40^{1/2}$ ] . experimentally the chargino masses can be measured very precisely either by threshold scans or in continuum above the threshold @xcite .
since the chargino production cross sections are simple binomials of @xmath41 , see fig.[fig : char ] , the mixing angles can be determined in a model independent way using polarized electron beams @xcite . based on this high - precision information
, the fundamental susy parameters can be extracted in analytic form .
inverting eqs.([massch],[mixch ] ) one finds to lowest order : @xmath42^{1/2}\label{eq : m2}\\ \left|\mu\right|&=&m_w[\sigma + \delta[\cos2\phi_r+\cos2\phi_l]]^{1/2 } \label{eq : mu}\\ \cos\phi_\mu&= & [ \delta^2 -(m^2_2-\mu^2)^2 - 4m^2_w(m^2_2+\mu^2 ) \nonumber \\ & & -4m^4_w\cos^2 2\beta]/8 m_w^2m_2|\mu|\sin2\beta
\label{eq : cos}\\ \tan\beta&=&\left[\frac{1+\delta ( \cos 2\phi_r-\cos 2\phi_l ) } { 1-\delta ( \cos 2\phi_r-\cos 2\phi_l)}\right]^{1/2 } \label{eq : tan}\end{aligned}\ ] ] where @xmath43 and @xmath44 .
if both @xmath45 and @xmath46 can be measured , the fundamental parameters ( [ eq : m2]-[eq : tan ] ) can be extracted unambiguously . however ,
if @xmath47 happens to be beyond the kinematical reach at an early stage of the lc , it depends on the cp properties of the higgsino sector whether they can be determined or not in the light chargino system alone @xcite _ ( i ) _ if the higgsino sector is cp invariant , @xmath48 can be exploited to determine @xmath46 up to at most a two fold ambiguity .
this ambiguity can be resolved if other observables can be measured , e.g. the mixed
pair @xmath49 production cross sections . _
( ii ) _ in a cp non invariant theory the parameters in eqs.([eq : m2][eq : tan ] ) remain dependent on the unknown heavy chargino mass @xmath46 .
two trajectories in the plane @xmath50 $ ] are generated ( and consequently in the @xmath51 space ) , parametrized by @xmath46 and classified by the two possible signs of @xmath52 .
the analysis of the two light neutralino states @xmath53 and @xmath54 can be used to predict the heavy chargino mass @xmath46 in the mssm .
therefore we will now discuss the mass matrix of the @xmath55 is symmetric but nondiagonal @xmath56 where @xmath57 , @xmath58 .
the mass eigenstates , neutralinos , are obtained by the @xmath59 diagonalization matrix @xmath60 , which is parameterized by 6 angles and 10 phases as @xmath61 where @xmath62 are @xmath59 matrices describing 2-dim complex rotations in the \{jk } plane ( of the form analogous to @xmath63 in eq.([chardiag ] ) and defined in terms of ( @xmath64 , @xmath65 ) .
the cp is conserved in the neutralino sector if @xmath66 and @xmath67 .
the unitarity constraints can conveniently be formulated in terms of unitarity quadrangles built up by + @xmath16 the links @xmath68 connecting two _ rows _ @xmath69 and @xmath70 + @xmath16 the links @xmath71 connecting two _ columns _ @xmath69 and @xmath70 .
+ unlike in the ckm or mns cases of quark and lepton mixing , the orientation of all quadrangles is physical @xcite . to resolve the light chargino case in the cp - violating scenario _
( ii ) _ , we note that each neutralino mass satisfies the characteristic equation @xmath72 where @xmath73 , @xmath74 , @xmath75 and @xmath76 are binomials of @xmath77 and @xmath78 .
therefore the equation for each @xmath79 has the form @xmath80 i.e. each neutralino mass defines a circle in the @xmath81 plane . with two
light neutralino masses two crossing points in the ( @xmath77 , @xmath78 ) plane are generated , as seen in the left panel of fig.[fig : circle ] .
since from the chargino sector @xmath82 are parameterized by unknown @xmath46 , the crossing points will migrate with @xmath46 , right panel of fig.[fig : circle ] .
one can use the measured cross section for @xmath83 to select a unique solution for @xmath26 and predict the heavy chargino mass .
if the lc runs concurrently with the lhc , the lhc experiments may be able to verify the predicted value of @xmath46 .
if the machine energy is above the heavy charginos and neutralinos , one can + @xmath16 study the threshold behavior of non - diagonal neutralino pair production to check + for a clear signal of nontrivial cp phases , + @xmath16 measure the normal neutralino polarization which provides a unique probe of + @xmath84 ( majorana ) cp phases , + @xmath16 exploit the sum rules to verify the closure of the chargino and neutralino sectors , + @xmath16 analyze the susy relations between yukawa and gauge couplings , + @xmath16 extract information on sleptons exchanged in the t - channels etc .
+ for more details , we refer to @xcite .
the sfermion mass matrix in the @xmath85 basis is given as @xmath86 where @xmath87 , @xmath88 and @xmath89 are slepton soft susy breaking parameters .
the mass eigenstates are defined @xmath90 the @xmath85 mixing is important if @xmath91 .
therefore for the first and second generation sfermions the mixing is usually neglected .
@xmath92 @xmath93 + the slepton masses can be measured at a high luminosity @xmath0 collider by scanning the pair production near threshold @xcite .
since the expected experimental accuracy is of @xmath94 mev , it is necessary to incorporate effects beyond leading order in the theoretical predictions @xcite .
the non - zero widths of the sleptons , which considerably affect the cross - sections near threshold , must be included in a gauge - invariant manner .
this can be achieved by shifting the slepton mass into the complex plane , @xmath95 . moreover , for the production of off - shell sleptons the full @xmath96 matrix element , including the decay of the sleptons , must be taken into account as well as the mssm background and interference contributions .
one of the most important radiative corrections near threshold is the coulomb rescattering correction due to photon exchange between the slowly moving sleptons .
beamstrahlung and isr also play an important role . the production of smuons and staus proceeds via s - channel gauge - boson exchange , so that the sleptons are produced in a p - wave with a characteristic rise of the excitation curve @xmath97 , where @xmath98 is the slepton velocity . due to the exchange of majorana neutralinos in the t - channel , selectrons
can also be produced in s - wave ( @xmath99 ) , namely for @xmath100 pairs in @xmath0 annihilation and @xmath101 pairs in @xmath17 scattering .
expectations for the r - selectron cross - sections at both collider modes are shown in fig.[fig : thrsel ] with the background from both the sm and mssm sources , reduced by appropriate cuts , included @xcite . using five equidistant scan points ,
four free parameters , the mass , width , normalization and flat background contribution , can be fitted in a model - independent way .
in contrast to the first two generation sfermions , large mixing are expected between the left- and right - chiral components of the third generation sfermions due to the large yukawa coupling .
the mixing effects are thus sensitive to the higgs parameters @xmath8 and @xmath22 as well as the trilinear couplings @xmath102 @xcite .
for instance , by examining the polarization of the taus in the decay @xmath103 , fig .
[ fig : taupol ] , a recent study within the mssm @xcite finds that @xmath22 in the range of 3040 can be determined with an error of about 10% .
moreover , if @xmath104 or @xmath8 turn out to be complex , the phase of the off - diagonal term @xmath105 modifies @xmath106 properties . although the best would be to determine the complex parameters by measuring suitable @xmath107 violating observables , this is not straightforward , because the @xmath108 are spinless and their main decay modes are two body decays . however , the @xmath107 conserving observables also depend on the phases .
for example , the various @xmath109 decay branching ratios depend in a characteristic way on the complex phases @xcite .
this is illustrated in fig .
[ taubr ] .
the fit to the simulated experimental data with 2 ab@xmath110 at a collider like tesla shows that @xmath111 and @xmath112 can be determined with an error of order 10% .
similarly , for the @xmath113 and @xmath114 sectors , the @xmath115 mixing can be important . by measuring the production cross sections with polarized beams
the squark masses and mixing angles can be determined quite precisely @xcite , see fig.[fig : stop ] . for more details on the sfermion sector
, we refer to @xcite
why we need high precision measurements ? the standard model physics is characterized by energy scales of order 100 gev .
however we expect the origin of supersymmetry breaking at the high scale , near the planck scale @xmath116 gev or the grand unification [ gut ] scale @xmath117 gev .
information on physics near the planck scale may become available from the well - controlled extrapolation of fundamental parameters measured with high precision at laboratory energies .
although such extrapolations exploiting renormalization group techniques extend over 13 to 16 orders of magnitude , they can be carried out in a stable way in supersymmetric theories @xcite .
such a procedure has very successfully been pursued for the three electroweak and strong gauge couplings providing the solid base of the grand unification hypothesis .
this method can be expanded to a large ensemble of the soft susy breaking parameters : gaugino and scalar masses , as well as trilinear couplings .
recently this procedure has been applied @xcite to the minimal supergravity ( with a naturally high degree of regularity near the grand unification scale ) and confronted with the gauge mediated supersymmetry breaking gmsb , see fig.[fig : extra ] . the basic structure in this approach is assumed to be essentially of desert type , although the existence of intermediate scales is not precluded .
an interesting example , the left - right extension of msugra incorporating the seesaw mechanism for the masses of right - handed neutrinos , as well as a string - inspired effective field theory example , can be found in @xcite .
this bottom - up approach , formulated by means of the renormalization group , makes use of the low - energy measurements to the maximum extent possible .
therefore high - quality experimental data are necessary in this context , that should become available by future lepton colliders , to reveal the fundamental theory at the high scale .
a ) @xmath118 [ gev@xmath119 b ) @xmath120 [ gev@xmath121 + ( 150,-15)@xmath122 [ gev ] ( 350,-15)@xmath122 [ gev ]
data rules !
we need them badly . the lhc will provide plenty of data , however , their theoretical interpretation will be possible in specific models . in this context
the @xmath0 linear collider is very much welcome .
overlap of the lc running with the lhc would greatly help to perform critical tests : quantum numbers , masses , couplings etc .
we have demonstrated that from the future high - precision data taken at @xmath0 linear colliders , tesla in particular , and combined with results from lhc , and clic later , the low - energy parameters of the supersymmetric model can be determined . then the bottom - up
approach , by evolving the parameters from the low - energy scale to the high scale by means of renormalization group techniques , can be exploited to reconstruct the fundamental supersymmetry parameters at the high scale , gut or planck , providing a picture in a region where gravity is linked to particle physics , and superstring theory becomes effective directly .
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instytut fizyki teoretycznej , uniwersytet warszawski + pl00681 warsaw , poland |
SEAL Team Six Offers an Entertaining Look at bin Laden Raid, But Won't Sway Voters
Controversy arose when the National Geographic Channel announced that it will premiere a film about the successful military raid that killed Osama bin Laden two days before the presidential election, but anyone who walks away thinking that SEAL Team Six: The Raid on Osama bin Laden is a political piece has blinders on.
From the first 15 minutes — which include an intense, violent firefight — it's clear that the film's purpose is to provide entertainment, not to advance a political agenda. President Barack Obama is merely a background player (albeit an obviously necessary one), while the real focus is on the Navy SEALs and CIA officials who planned and executed the operation. Any influence the movie — the network's first feature film based on true events — will have on undecided voters is dubious at best.
Watch President Obama announce the death of Osama bin Laden
Though actors portray the key players, the film is shot documentary-style (mixed with archival news footage and photos), beginning with a dramatization of the interrogation of a prisoner at Guantanamo Bay that eventually led intelligence officials to the compound at Abbottabad, Pakistan, where bin Laden was hiding.
At a National Security meeting on April 28, 2011, Vice President Joe Biden and Defense Secretary Robert Gates advised President Obama against the raid, code-named "Operation Neptune's Spear," while Secretary of State Hillary Clinton and CIA Director Leon Panetta were in favor of it. (Director John Stockwell, for the record, calls Obama's call to give the go-ahead a "terrible political decision." "The risk/reward ratio was not weighted in his favor," the director said. "Like a coach who makes the call to go for it on fourth down, it's only a 'gutsy' call when it works. When it doesn't, you lose your job.")
Shot in India ("a country which didn't like being used as a stand-in for their hated enemy," according to Stockwell), as well as a working prison in New Mexico, the film understandably contains a number of Hollywood embellishments to ensure it's made-for-TV entertainment. But such aspects as military maneuvers and training procedures were submitted for approval to a team of experts, including a retired Navy SEAL, a top CIA operative and a bin Laden historian.
After deftly outlining the process by which the CIA gathered evidence that bin Laden was hiding in the compound — a two-man surveillance team renting a house across from the property plays a key role — Stockwell achieves his two greatest accomplishments in the film. First, he manages to both humanize the SEALs by showing footage of them training and talking to their loved ones back home — and suspecting that the mission they're training for is targeting bin Laden, but not knowing for sure and realizing that they wouldn't be able to tell anyone even if it were.
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Secondly, Stockwell manages to make the middle-of-the-night raid sequence a real nail-biter, even though everyone knows the outcome. Still, when one of the military helicopters nearly crashes outside the compound, you might find yourself wondering if maybe the news reports got it wrong after all. That narrowly-avoided disaster, according to the film, is what prompted the famous photo of Obama, Clinton and other officials looking horrified as they watched from the Situation Room in the White House.
The team members depicted are identified only by their code names — Stunner, Mule, Trench and the like — in order to preserve anonymity for the real men involved in the top-secret operation. Stockwell makes two of them the main players of the film: "surfer boy" team leader Stunner (Cam Gigandet) and Cherry (Anson Mount), a self-described "hot-headed redneck."
On the other end of things, Boss' Kathleen Robertson gives an excellent performance as CIA analyst Vivian Hollins, whose quest to find bin Laden borders on a physical need. "Being obsessed with the target is like having a one-way affair," she says at one point. "It's secret and you can't stop thinking about him, but you're always alone."
Though the SEALs are the real heroes of the film, it's the governmental, behind-the-scenes sequences that are the most fascinating parts of SEAL Team Six. Essentially three options were on the table: planning a joint attack with the Pakistani government, which some believe may have actually been abetting bin Laden; leveling the compound, which carried the risk of never knowing for sure whether bin Laden was inside, not to mention collateral damage; or executing a helicopter attack with only a 40 to 60 percent certainty that bin Laden was in the compound.
Wisely, rather than having an actor credited as bin Laden, Stockwell never shows the Al Qaeda leader's face as he's executed, but rather depicts him as just a shadowy, tall figure in one of the rooms of the compound. The actual killing is fairly muted, with the more eye-popping aspect of the raid being the team's success in rescuing the several women and children who were also there.
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Produced by The Hurt Locker's Nicolas Chartier, SEAL Team Six provides a taut, entertaining look at one of the most important historical events in recent U.S. history — and viewers, regardless of political leanings, will agree that it has a satisfying ending.
SEAL Team Six: The Raid on Osama bin Laden premieres Sunday at 8/7c on the National Geographic Channel. It will be available on Netflix Monday. ||||| “SEAL Team Six,” a shallow TV movie about the raid to kill Osama Bin Laden, stars a bevy of beefcakes in Navy SEAL costumes — and Barack Obama. Real audio and video footage of the president has been threaded into a fictional, melodramatic account of the attack on Abbottabad. Couple this with the film’s air date, tonight on National Geographic, just three days before the election, and “SEAL Team Six” has been accused of being Democratic propaganda, burnishing Obama’s accomplishments, though its creators — director John Stockwell and producers the Weinstein brothers — have said they included Obama only to increase verisimilitude. But as either propaganda or realist fiction “SEAL Team Six” is ineffective. It’s on the level of those “The army is just like a character-building video game!” enlistment ads you see before movies, simple-minded and, at most, superficially rousing. Barack Obama probably isn’t wild about help this dim.
“SEAL Team Six” opens in 2002 at Guantánamo Bay, where two men we’ve never seen, one a prisoner and one an interrogator, are having a chat. The interrogator explains he’s going to send the prisoner off to the Saudis where they are going to peel off all of his skin unless he can help. The prisoner gives up the name of Osama Bin Laden’s courier. We never see either of these men again, but as the credits play, we see where this information leads: Documents get highlighted as the courier is I.D.-ed and located. By the time the credits are over, ten years have passed — ten years in which almost all of the work to find and locate Osama Bin Laden has been done. “SEAL Team Six” goes from the one scene that could appear in an action movie to … all the other scenes that could appear in an action movie.
By eliding all the boring, non-bullety stuff, “SEAL Team Six” makes time to soapify its SEALs. We are introduced to the squad as they undergo a character-testing trauma, which causes two of its more handsome members — Stunner, the all-American surferboy team leader (Cam Gigadnet of “The OC” and “Twilight”) and Cherry, the grizzled short-tempered redneck (Anson Mount of “Hell on Wheels”) — to dislike each other, paving the way for a whole scene dedicated to one of the most dispassionate fistfights I’ve ever seen. (At the end of the movie, when the mission is over, they fist bump. Resolution.)
The two guys, along with their colleagues — who include “Six Feet Under’s” Freddy Rodriguez as Xzibit, “Prison Break’s” Robert Knepper, who will just always be creepy, even when playing a hero — train, shoot things, have meaningful Skype chats with their families back home, joke around and shoot more things. It all feels like a lame simulacra of other, better, grittier war movies from “Generation Kill” to “Black Hawk Down.” ||||| A movie that feels like a documentary at times, a cheesy docudrama at others and some kind of slapped-together film that wants to be taken seriously as well. TWITTER
The movie beats Kathryn Bigelow’s "Zero Dark Thirty" by airing -- controversially -- on Nat Geo two days before the election, but Republicans really shouldn't worry, writes Tim Goodman.
The National Geographic Channel might have won the race to be the first to portray the events that led to the killing of Osama bin Laden -- beating Kathryn Bigelow’s Zero Dark Thirty to the big screen by rushing to the small screen Nov. 4 -- but it’s still too soon to say if being the first is the same as being the best.
Nat Geo will air SEAL Team Six: The Raid on Osama bin Laden at 8 p.m. Sunday (and has opened in theaters internationally). The film comes from The Weinstein Co. and is directed by John Stockwell (Into the Blue, Turistas, Crazy/Beautiful) and produced by Nicolas Chartier, who was a producer on The Hurt Locker, Bigelow’s best picture Oscar winner.
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Both SEAL Team Six and Zero Dark Thirty have been pre-emptively called enablers for President Obama, since the killing of bin Laden was a major coup for him. But SEAL Team Six will come under more scrutiny because it will air two days before the election and then be available the next day on Netflix.
Still, it’s hard to imagine this film -- or even the unseen, save for trailers, Zero Dark Thirty -- moving the needle on an election. Why? Because everyone in the world knows what happened and how it ended. The whole thing is in the history books. And with the publication of No Easy Day from SEAL member Mark Owen, it’s not like the world lacks for details if people really want to seek them out.
But if any Republicans are worried that this sneaky little move by Nat Geo and TWC could be a knockout blow or even a jab in next week's election, they should rest easy. That’s because the film really isn’t that good.
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All the compelling parts are precisely as you’d imagine them to be: the intelligence reports that unearthed bin Laden’s whereabouts in Pakistan, the risk of every attack option, the stark reality that the intel might be wrong and the United States -- and, by extension, Obama -- would be embarrassed and finally the nerve-wracking mission itself.
It doesn’t take much of a genius or even a dramatist to understand that those are the core elements. In fact-based dramas, knowing the ending is a real hindrance because there’s no mystery or suspense. When the SEALs enter the compound, you know they’re not going to be killed. You know they’re going to get bin Laden, they’re going to get away and the near screw-up with one of the two helicopters going down in the compound is not going to ruin everything.
So where’s the drama? Technically, you don’t need any more drama than all of the action listed above; you just need a director and a budget that’s going to make the whole thing pulse-pounding and badass. Parts of SEAL Team Six: The Raid on Osama bin Laden make that happen, but the 90-minute film misses the essential element that it needed (and Bigelow’s film will need): character development.
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Stockwell’s film resorts to the now-boring conceit of having the participants talk to the camera. This exposition is not only a cheat, cutting corners by telling when it could be showing, but it never lets the audience feel anything for the characters. They are mostly cardboard cutouts.
SEAL Team Six stars Cam Gigandet as Stunner, the team leader; Anson Mount as Cherry, the more renegade SEAL who has trouble being led by the younger Stunner; rapper Xzibit (Alvin Joiner) playing Mule; Freddy Rodriguez as Trench; and Kenneth Miller as Sauce rounding out the team. Robert Knepper is billed as merely Lt. Commander.
The problem with that list is that Gigandet is allowed almost no time to show the audience he’s the team leader. Mount steals the better material and only in rare flashes do we learn anything about the others. In fact, there’s so little of Sauce in the film that he’s barely a seasoning. You can’t mine drama from characters you’re not manipulated into liking or loathing.
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The person who gets the most mileage out of SEAL Team Six is Kathleen Robertson (Boss) as Vivian Hollins, the CIA analyst who has been hellbent on getting bin Laden since the Sept. 11 attack on the Twin Towers. There are two problems here. First, any fan of Homeland, the Showtime series that just swept the Emmys, will think is that Robertson is essentially Claire Danes playing Carrie, the CIA analyst hellbent on bringing down the fictional Abu Nazir after the Sept. 11 attacks. Robertson, who does great work on Boss, isn’t given anything remotely interesting for her character – like Carrie’s mental issues and her love of jazz – and instead gets the most clichéd, rote dialogue to read as she talks to the camera in those faux interviews.
Eddie Kay Thomas and William Fichtner are in this movie as well, but they are also ghosts who leave little memory for the viewer.
That’s not to say that some of the combat scenes in SEAL Team Six are not riveting, as is the aforementioned final days and minutes leading up to the raid on Bin Laden’s compound. But with almost no emotional interest in these undeveloped characters, the movie feels more like it was tossed together in an effort to be first on any screen – small or large.
VIDEO: 'Seal Team Six' Prepares to Hunt Osama Bin Laden in New Clip
SEAL Team Six is interspersed with photos and interviews of Obama and the players around him during that difficult decision process, and if you’re really into that sort of thing you could spot one or two moments that certainly looked like political ads. A photo of Obama mulling over something enormous certainly gives him gravitas and there’s more than a few shots with American flags after the news of Bin Laden’s death.
But this is a movie that feels like a documentary at times, a cheesy docudrama at others and some kind of slapped together film that wants to be taken seriously as well. Whatever you may think of how it was sewn together, SEAL Team Six isn’t particularly bad, it’s just not particularly good or interesting.
What is interesting is that in the Nat Geo press materials, Stockwell gets a page and a half for a “director’s statement,” then another page and a half for an essay called “Can a Movie Swing an Election?”
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The latter isn’t particularly convincing and the former brings up interesting questions about the process that might have made for fantastic dramatic scenes. Unfortunately, they’re not in the movie. For example, here’s something Stockwell writes in his statement: “What if bin Laden had fled the compound when he heard the approaching choppers? Would we have pursued him through the streets of Abbottabad? What if the Pakistan military had shot down one of our helicopters; engaged in a firefight with our troops and took hostages; or used fighter jets? There were also suspicions that the house was rigged to explode or that the occupants had a cache of Stinger missiles and the enclosed rooftop patio was the perfect launching pad to take down the vulnerable hovering Blackhawks. What if large numbers of the women and children in the compound had been injured or killed? What if there had been Americancasualties? And the most potentially disastrous outcome – what if any of the above had happened, and the intended target of the raid wasn’t even there?”
What if, indeed.
Those are great questions raised by the director. But what if he was able to convey all of them more convincingly and more dramatically in the actual movie? That would have been something.
Kathryn Bigelow, what have you got?
Email: Tim.Goodman@THR.com
Twitter: @BastardMachine ||||| Some fuss was recently made over the role President Obama plays in "SEAL Team Six: The Raid on Osama bin Laden," a docu-drama premiering on National Geographic Channel on Sunday. There were accusations that the timing — days before the election — and the late-hour insertion of additional footage of the president, including a voice-over describing the decision-making process, were designed to boost Obama's reelection bid.
Despite subsequent protests from the network and the filmmakers, the partisan kerfuffle can work only to their advantage; no doubt more people will watch "SEAL Team Six" in light of the mild controversy. And perhaps for a moment our nation will be united on one point: The president's screen time, which, frankly, does not seem excessive, is the least of this film's problems.
Docu-dramas are often dicey enterprises, especially when they involve a) classified material, b) political assassination, and c) an event that occurred in recent memory. It's one thing to engage in a little "loosely based" fudging about the court of Marie Antoinette or even the rescue of American Embassy workers in 1979.
TIMELINE: The path to bin Laden
But the dust from Operation Neptune Spear has barely settled. And despite the credentials of those involved, including director John Stockwell ("Into the Blue"), "Hurt Locker" producer Nicolas Chartier and the Weinstein Co., "SEAL Team Six" was worrisome from the get-go.
Predictably, the filmmakers have chosen to use a mix of real and staged footage to tell the story. Less predictably, and far less wisely, the staged portions include a series of expository "interviews" with the principal characters, though who they are being interviewed by, or for what purpose beside narrative laziness, is never made clear.
The film's most troubling aspect is the cartoonish nature of these characters, who get the lion's share of screen time. Including and especially, Vivian Hollins a female CIA analyst played by Kathleen Robertson in lip gloss and pencil skirts.
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According to "No Easy Day," a first-person account written by real-life former SEAL Team Six member Matt Bissonnette under the pseudonym Mark Owen, there was indeed a key female analyst involved in promoting the mission, and possibly she is quite young and attractive. But, honestly, do we always have to go blond hottie behind smarty-pants glasses for roles like these? (At least in "Homeland," Claire Danes' comely CIA agent Carrie has a genuine mental illness. Also, no fake glasses.)
Vivian is clearly the Carrie stand-in here. After a prisoner in Guantanamo gives up a name that belongs to an Al Qaeda courier, she has him tracked, discovers the mysterious Pakistani compound and is soon insisting — correctly, as it turns out — that the 6-foot-5 guy strolling around behind the walls is Bin Laden. William Fichtner plays her immediate supervisor (with Defense Secretary Leon E. Panetta represented only by phone), an equally trite character, who keeps saying things like, "I need more evidence." This is what passes for ancillary plot.
Vivian isn't the only character pulled from the Idiot's Guide to Stock Characters. There are the team members themselves, who break down essentially into the white redneck charmer Cherry (Anson Mount), the white preppie team leader Stunner (Cam Gigandet) and the black family guy Mule (Alvin Joiner a.k.a. Xzibit). Cherry and Stunner have some "issues": Cherry thinks Stunner is too young for the job, Stunner worries he is right. And this is what passes for character development.
Although particularly insulting when you consider the true heroics and canny intelligence the operation entailed, "SEAL Team Six" is undone by the inevitable conundrum of any docu-drama: Which side do you favor — the docu, or the drama?
If it's the documentary, then the story rests on the revelation of true and historic detail. We all know how it ends, so getting there must provide the tension. If it's the drama, then you have to be willing to sacrifice certain intricacies of plot in the interest of fleshing out the characters.
"SEAL Team Six," though inevitably exciting in its conclusion and touching at times, refuses to commit either way. This failure of nerve not only dooms the film as both docu- and drama but also contradicts its main theme.
Because when the president and those around him were faced with ordering a mission that could just as easily failed as succeeded, they did make the call.
---
Where: National Geographic Channel
When: 8 p.m. Sunday
mary.mcnamara@latimes.com | – Harvey Weinstein is trying to give President Obama an electoral boost with SEAL Team Six, a feature airing tonight on National Geographic about the assault on Osama bin Laden's compound. But critics had trouble staying awake: "As either propaganda or realist fiction SEAL Team Six is ineffective," writes Willa Paskin at Salon. "It’s on the level of those 'The army is just like a character-building video game!' enlistment ads you see before movies, simple-minded and, at most, superficially rousing." "Predictably, the filmmakers have chosen to use a mix of real and staged footage to tell the story," writes Mary McNamara at the LA Times. " Less predictably, and far less wisely, the staged portions include a series of expository 'interviews' with the principal characters, though who they are being interviewed by ... is never made clear." The combat scenes are pretty good, writes Tim Goodman at the Hollywood Reporter, "but with almost no emotional interest in these undeveloped characters, the movie feels more like it was tossed together in an effort to be first on any screen—small or large." Bucking the trend, Liz Raftery at TV Guide calls SEAL Team Six "a taut, entertaining" film with fascinating backroom scenes about political decision-making. What's more, "the film's purpose is to provide entertainment, not to advance a political agenda." |
diabetes is among the chronic diseases that feature significantly in public health and are the greatest cause of disability and premature death in europe .
diabetes is a chronic , and largely preventable , disease that can lead to cardiovascular disease , blindness , kidney failure , loss of limbs and loss of life .
it causes suffering and hardship for the approximately 60 million people in the european region currently living with the disease , while also straining its health systems .
prevalence of diabetes is increasing in the european region , already reaching rates of 10 - 12% of the population in some countries .
this increase is strongly associated with risk factors such as overweight and obesity , unhealthy diets , physical inactivity and socioeconomic disadvantage .
these risk factors also contribute to the development of the other three non - communicable diseases ( ncds ) cardiovascular disease , chronic respiratory diseases and cancer , making imperative the prevention of diabetes . according to the world health organization , who 346 million people worldwide have diabetes . in 2004
more than 80% of diabetes deaths occur in low- and middle - income countries . who projects that diabetes death will double between 2005 and 2030 .
healthy diet , regular physical activity , maintaining a normal body weight and avoiding tobacco use can prevent or delay the onset of type 2 diabetes .
diabetes is a progressive disease that affects the patient s physical , cognitive , emotional , familial and social functions and well - being .
many researchers have , in recent years , shown particular interest in diabetes and have systematically focused their attention on the training of the diabetic patient .
one of the most significant developments is that of specialist clinical nurses to educate diabetics ( adults and children ) and their families .
nursing is a multi - aspect profession that calls for a high degree of specialist knowledge .
that is why johnson ( 1966 ) recommends the introduction of the specialist clinical nurse . in the late 1960s it became necessary to have suitable postgraduate training , in order
specialty in nursing presupposes a higher degree of specialist knowledge , skills and necessary qualities in the specific area than basic training in general nursing provides .
shari defines the specialist clinical nurse as a nurse with additional training , who provides direct nursing for specific patients in a particular area of nursing .
the specialist clinical diabetes nurse is defined as a health care professional who possesses basic knowledge and skills in life and social sciences , communication and counseling , and is experienced in the care of diabetics .
the number of specialist diabetes clinical nurses in great britain has increased steadily in recent years because of the increased incidence of diabetes in children coupled with increased awareness of the needs these children have .
nurses work in hospitals and in the community in close collaboration with other health professionals , with the children themselves , their families and teachers .
harmic and fenton divide the work of the clinical nurse specialist into direct and indirect activities .
direct work includes the following : i ) providing regular nursing for a small group of patients ; ii ) analyzing complex clinical problems ; iii ) selecting and applying methods ; iv ) participating in clinical meetings ; v ) training patients individually or in groups ; vi ) creating support groups for patients and their families ; vi ) acting in crises ; vii ) providing emotional and social support for patients and families .
indirect work includes the following : i ) creating staff support groups ; ii ) collaborating with nursing staff to produce care plans ; iii ) developing methods and procedures ; iv ) participating in activities designed to maintain quality ; v ) referring patients to other services .
the clinical nurse specialist plays a definitive role in the hospital , in the community and at school .
clinical specialist nursing is a new approach and aims to improve the quality of the training a diabetic receives .
the clinical diabetes nurse specialist has specific responsibilities regarding the assessment of the diabetic patient .
assessment is not only about how knowledgeable patients are of their condition , but also of what they need in the way of training and how prepared they are to learn .
specific instruction concerning medication , equipment , diet / nutrition must be incorporated in all patient educational programs .
all those programs must result in documentation that the patient and family understand what has been taught .
the burden of managing diabetes is on the parents to a greater or lesser degree , depending on the age of the child .
continuous training of parents and child is therefore an important factor in the effective treatment of the disease .
training should not be confined to the patient only , but should extend to include at least one more member of the family .
even so , the consensus emerging from practical studies seems to point more and more to the fact that children and adolescents who undertake more responsibility in the management of their diabetes treatment make more mistakes in maintaining the daily treatment regime , are less inclined to adhere to the program and have less control over their metabolism than those whose parents are more involved in their treatment routine .
a literature review was done using key words such as diabetic training , nurse , educational programs in google scholar and research outcomes that describe the significance of training of diabetics are described in this article .
hernandez and williamson did research at a diabetic training center in canada with a view to assessing the impact of training and awareness on young people with diabetes type i. the twenty - nine diabetic children who took part in the study all attended a one - hour training session on diabetes .
data was gathered from questionnaires that the subjects filled in immediately before and after the training session and a further questionnaire that they filled in one year later .
the findings indicated that the session produced favorable short term and long term results in promoting awareness of diabetes , as well as the beneficial results of keeping blood sugar levels within normal limits , pointing out the value of educating patients .
another study carried out by polonsky et al . at the tripler army medical centre in hawaii assessed the results of a specific training program for diabetic patients ( diabetes outpatient intensive treatment ) .
the first stage involved 167 people and the second stage ( 6 months after training ) involved 117 .
the data , gathered through a variety of psychometric tools , demonstrated that participants were more aware of blood sugar levels and sought greater medical supervision .
moreover , their eating habits improved and they reduced their intake of carbohydrate and lipids .
though there are studies that are in favor of the positive results of diabetes training for adults and children , there are others that draw different conclusions .
this systematic review looked into the beneficial effects on a number of outcomes of the interventions in children with diabetes type i , and aimed specifically at improving diabetes management .
it gives a detailed description of 62 studies , most of which were carried out in the us and canada .
the studies were mainly quantitative studies using the randomized controlled trials ( rct ) approach .
the trials were carried out in a variety of institutions ( hospitals , clinics and training centers ) with an average of 53.8 people participating .
the results showed that training and socio - psychological intervention was of limited benefit to the diabetic patient .
even so , the conclusion was that the various forms of intervention may produce better results when specific aspects of diabetes are targeted rather than adopting a general approach to the whole problem . a study by cowan et al .
at the university hospital of wales pediatric clinic assessed the impact of specialist diabetes clinical nurses in diabetes care management over a three - year period .
the study compared the care management of 154 diabetic children before and after being put on the specialist clinical diabetes nursing program .
study of the data on clinical management and blood sugar level management showed significant improvement in training the diabetic children , in their clinical management and in admissions to the hospital during their specialist diabetes clinical nursing .
lowes took this study a step further and assessed the effect of specialist diabetes clinical nursing on diabetic children two years after starting the programme .
the results showed a significant ( 50% ) drop in the time children who had been diagnosed as diabetic spent in hospital .
the seven training sessions for children and their parents were very well attended ( 91% ) and children and parents alike had very positive feelings about the content of the sessions .
though the results of this study favor the introduction of specialist diabetes clinical nursing in the care and management of childhood diabetes , the small number of subjects and geographical limitations of the study mean that the results can not be presumed generally applicable .
moyer set out to compare the care provided for diabetic children and their parents at diabetes clinics with and without specialist diabetes clinical nursing programmes .
there were 161 families in the study , 89 of whom attended clinics without specialist diabetes clinical nursing programs .
the results showed that children who had access to specialist diabetes clinical nursing programs demonstrated higher levels of awareness of issues related to diabetes and the techniques of administering insulin than children who had no such access .
another study by tselika - garfe et al . carried out at p. and a. kyriakou paediatric hospital in athens set out to look into problems that adolescent patients with diabetes face at home , at school and in the community .
their subject group consisted of 56 adolescents between the ages of 11 to 19 , 87.5% of whom injected themselves with their insulin .
even so , only one of their numbers was aware of the implications of insulin treatment .
the only source of information for most of these adolescents was the doctor at the hospital or another doctor .
the results of the study show how important the provision of information is to adolescents with diabetes .
nurses with special knowledge in diabetes have an important role to play in training patients and dealing with complications arising from the disease .
coping with the disease requires knowledge of its nature and ways of adapting to the new way of life it imposes .
nowadays , diabetes is usually managed by a team of professionals consisting of doctors , nurses , psychologists and dieticians who specialize in the disease and help sufferers and their families adapt to the new way of life while also keeping the disease under control .
well - trained , experienced specialist diabetes clinical nurses provide better patient and career training , are more committed , are better listeners and empathize more with their patients .
they inspire trust and make their diabetic patients feel secure so they are more willing to co - operate .
they also help patients turn their mistakes into learning experiences which provide them with correct solutions in managing their disease .
they play a more active part in prescribing medication and willingly take on more responsibility than general medical practitioners .
it is the parents that provide support and care for diabetic children in the initial stages of the disease and they often need more psychological support in order to meet the challenges of the demanding care program they have to adhere to for their children .
the care program focuses mainly on the times of day when blood sugar levels have to be measured and insulin injections have to be given .
it is the specialist diabetes clinical nurse who helps parents in the role of caring for their child by providing the right information and teaching the skills and techniques they need to manage this chronic disease .
specialist diabetes clinical nurses also need to collaborate with parents to ensure continued care of the children when they are discharged from hospital .
consequently , nurses certified in this area are needed to educate patients and prospective patients about diabetes , and discuss diabetes prevention and care . | diabetes is a major health problem with many social and economic consequences in general population .
the importance of education in the diabetic patient and his family , led to the development of diabetes clinical nurse specialist .
the role of diabetes clinical nurse specialist is essential and crucial to the hospitals and the community , in order to form a relationship with the diabetic patient and his / her family . in this way health
is promoted to the maximum extent possible . in conclusion
educational programs help patients with diabetes to obtain information about their condition and improve their self - care skills . |
there is a body of evidence suggesting that type 2 diabetes is programmed in utero [ 1 , 2 ] .
fetal programming is the process through which fetal malnutrition leads to lifelong changes in the body organs and systems in ways that might cause disease in later life .
there is some evidence that obesity , a major risk factor for type 2 diabetes , is also programmed in utero .
maternal hyperglycemia is associated with obesity in the next generation [ 4 , 5 ] .
women who were in utero during the dutch famine tended to be overweight as adults as a consequence of early programming .
fetal nutrition depends on the placenta ability to transport nutrients to the fetus from its mother .
small babies generally have small placentas , but , in some circumstances , an undernourished fetus can expand its placental surface to extract more nutrients from the mother .
this phenomenon is well known to sheep farmers who induce placental expansion by undernourishing ewes in midgestation . when the ewes are returned to good pasture the expanded placenta results in a larger fatter lamb than they otherwise would be .
there are findings suggesting that placental expansion occurs in humans through extension of the placental surface along its minor axis .
interestingly , in sheep placental expansion can only occur if the ewe was well nourished up to the time of mating .
maternal body size , especially height , can be used as a marker of her life time nutrition .
short maternal stature is a product of poor fetal and childhood nutrition , or recurrent exposure to infections , and genetic factors .
the peroxisome - proliferator - activated receptor 2 ( ppar2 ) gene encodes a nuclear hormone receptor that mediates adipocyte differentiation and regulates glucose and lipid metabolism [ 1417 ] .
variants of the ppar2 have repeatedly been linked to overweight , insulin resistance , and type 2 diabetes .
furthermore , ppar is known to play an important role in controlling placental vascular proliferation , trophoblast differentiation , and invasion [ 18 , 19 ] .
we have previously shown that the association between expansion of the placental surface with later hypertension is dependent upon maternal height .
we now speculate that the long - term costs could also include overweight and obesity in later life .
we therefore examined the long - term effects of placental expansions on overweight and body composition taking maternal height and genetic factors , the ppar2 gene , into account .
we examined this in the helsinki birth cohort study ( hbcs ) , which comprises people born in 193444 for whom the size of the placental surface was measured at birth .
the study cohort consists of 8760 men and women who were born between 1934 and 1944 in helsinki university central hospital and who visited child welfare clinics in the city .
details of the birth records and child welfare clinic records have been described [ 20 , 21 ] .
the weight and length of the baby at birth were recorded , and we calculated the ponderal index ( birth weight / length ) .
the records also included the weight of the placenta , together with the maximal so - called
diameter of the surface and a lesser diameter bisecting it at right angles .
the diameters were measured because it was recognized that the placental surface is more oval than circular and the two diameters were used to describe this .
assuming an elliptical surface , we estimated the surface area of the placenta as maximal lesser diameter /4 .
we used random number tables to select a sample of people within the cohort who were still living in finland . in order to achieve a sample size in excess of 2000 people we selected 2902 subjects and invited them to a clinic
the ethics committee at the national public health institute , finland , approved the study . at the clinic height and weight
body mass index ( bmi ) was calculated as weight ( kg ) divided by height ( m )
. estimates of total lean and fat mass were measured by bioelectrical impedance analysis using the inbody 3.0 eight - polar tactile electrode system , biospace co. , ltd , seoul , republic of korea , as described .
we analysed overweight using multiple logistic regression and percent body fat and lean body mass using multiple linear regression .
table 1 shows the measurements of birth and placental size and current body size , together with the frequency of the pro12pro genotype .
table 2 shows the odds ratios and regression coefficients for three outcomes , overweight ( bmi 25 kg / m ) , body fat percentage , and lean body mass , according to birth weight , ponderal index ( birth weight / length ) , and placental size .
the odds ratios and regression coefficients represent the change in each outcome that is associated with a 1 sd increase in birth size or placental size .
overweight was predicted by high birth weight and high ponderal index , while percent body fat was predicted by high ponderal index .
neither overweight nor percent body fat was predicted by measurements of placental size . as in previous analyses we divided the subjects around the mother 's median height ( 160 cm ) ( table 3 ) . in both maternal height groups
lean body mass was predicted by all measurements of body and placental size . among people
whose mothers were tall a long lesser placental diameter predicted both overweight and percent body fat .
there was a statistically significant interaction between the effects of mother 's height and the lesser diameter on percent body fat ( p for interaction = 0.02 ) . among people whose mothers were short , no measurements of placental size predicted overweight or percent body fat .
allele overweight was predicted by a large maximal diameter but there were no other associations between placental size and either overweight or percent body fat . among people with the pro12pro genotype large placental area and
a long lesser diameter predicted both overweight and percent body fat ( table 4 ) .
there were statistically significant interactions between the genotypes and the effects of placental area and the lesser diameter on overweight and percent body fat ( p for interaction = 0.004 and 0.05 for area and 0.03 and 0.09 for the lesser diameter , resp . ) . in people with the pro12pro genotype a long maximal diameter predicted overweight but not percent body fat . in a simultaneous regression with the lesser diameter
in the whole study sample placental size was not associated with either overweight or a high percent of body fat .
we found , however , that an expanded placental surface and a long lesser diameter predicted overweight and high percent of body fat in a subset of men and women whose mothers were tall and who carried the pro12pro genotype of the ppar2 gene .
higher birth weight was associated with an increased risk of having a bmi greater than 25 kg / m and with a greater lean body mass .
this has been shown before and suggests that birth weight influences adult body mass index through its effect on lean body mass [ 22 , 24 ] .
our findings suggest that lean body mass is related to the volume of placental tissue , reflected in its weight , while fat mass is related to placental surface area .
we have previously shown that an enlarged placental surface is associated with later hypertension , but this association was confined to people whose mothers were tall .
we interpreted this as evidence that compensatory placental expansion in humans is similar to compensatory expansion in sheep , in that it can only occur in women who were well nourished before they conceived .
we have shown that people who had an enlarged placental surface and later hypertension had above - average birthweight .
this is consistent with sheep farming practices in which placental expansion is induced by undernourishing ewes [ 10 , 12 ] .
the association between a large placental surface and later hypertension depended on a large lesser diameter rather than a large maximal diameter .
our findings for overweight and percentage body fat are similar in that they are only predicted by large lesser diameter .
this is a further evidence that tissue along the minor axis of the placental surface is qualitatively different to tissue along the major axis .
we suggest that placental expansion increases the nutrient supply to the fetus , but this supply is unbalanced .
we have previously proposed that compensatory placental expansion increases glucose transfer to the fetus , but this may not be matched by transfer of other nutrients , including proteins [ 26 , 27 ] .
placental enlargement could affect the fetus in the same way as high circulating maternal glucose concentrations , initiating biochemical changes that ultimately lead to obesity .
our findings suggest that this only occurs in people who are homozygotes for the pro12 allele of the ppar2 gene .
we have previously discussed limitations of the helsinki birth cohort study [ 20 , 21 ] .
the data are restricted to subjects who were born in helsinki university central hospital and attended voluntary child welfare clinics , did not emigrate , and were still alive and willing to participate in the year 2003 . however , we believe that our results , based on internal comparisons within the cohort , are unlikely to differ between those who attended and those who did not .
we have no information about what aspect of maternal malnutrition stimulated compensatory placental growth . in finland , as in other northern european countries , the long winters brought shortages of fruit and vegetables .
in addition , there were widespread food shortages around the time of the second world war , when our cohort was born .
we have found that a large placental surface area is associated with a high body fat percentage and an increased risk of being overweight in adult life .
we suggest that the enlarged surface is the result of expansion of the placental surface to compensate for fetal malnutrition in midgestation .
the association between the placental surface area and adiposity was only found in people with the pro12pro genotype of the ppar2 gene .
we suggest that there is an interplay between nutritional factors and genes at the placental level , which is affecting the later risk for obesity . | obesity is programmed in utero and small babies generally have small placentas . in some circumstances , an undernourished fetus can expand its placental surface to extract more nutrients .
we hypothesize that this results in an imbalanced nutrient supply to the fetus leading to obesity . to determine whether placental size determines overweight and body composition , we studied 2003 subjects in adult life . associations between placental surface area and indices of overweight were restricted to people who carried the pro12pro genotype of the ppar2 gene .
for every 1 sd increase in placental surface area , the odds ratio for overweight was 1.37 ( 95% ci 1.10 to 1.71 ; p = 0.005 ) .
expansion of the placental surface in compensation for fetal undernutrition increases the risk of overweight and a higher body fat percentage in people carrying the pro12pro genotype .
we suggest that similar underlying multifactorial mechanisms affect the development of obesity in general . |
in the eighties the numerous hydrogen lyman-@xmath0 absorption lines , called the _
ly-@xmath0 forest _ , seen in the spectra of quasars were interpreted as revealing a population of intergalactic clouds ( see sargent et al .
1980 ) .
the advent of numerical simulations changed the understanding of the low column density ly-@xmath0 forest , @xmath9 , from a population of discrete clouds to a smooth medium with density fluctuations produced by the process of structure formation ( cen et al .
1994 ; petitjean et al . 1995 ; miralda - escud et al . 1996
; zhang et al . 1998 ) .
this paradigm , confirmed by full hydrodinamical simulations ( cen et al .
1994 ; zhang , anninos & norman 1995 ; miralda - escud et al .
1996 ; hernquist , katz & weinberg 1996 ; wadsley & bond 1996 ; zhang et al . 1997
; theuns et al . 1998 ; machacek et al . 2000 ; efstathiou , schaye & theuns 2000 ) , also caused a change in the way we mathematically treat the absorption lines . since then the igm has become a unique tool to study the evolution of the gas in the universe ( becker et al .
2011 , bolton et al . 2013 ) and the large scale structures in the universe ( e.g. croft et al .
2002 , busca et al .
2012 ) thanks to the dramatic increase in the statistics provided by quasar surveys like the baryonic oscillation spectroscopic survey from sdss - iii ( eisenstein et al . 2011 ; pris et al .
2012 ) .
because the gravity of the underlying dark matter dominates , it is often assumed that the igm constitutes a stochastic field of spatially random fluctuations , since the cosmic mass is randomly distributed . in this
scenarioseveral statistical approaches as the flux decrement ( da ) , the flux power spectrum , the cumulative distribution function ( cdf ) and principally the probability distribution of ly-@xmath0 pixel optical depths ( pdf ) , have been used to analyze the observed ly@xmath0 forest ( fan et al .
2002 ; rollinde et al . 2005 ; guimares et al . 2007 ; becker et al . 2007 ; viel et al .
2008 ) . among the stochastic approaches , the detrended fluctuation analysis ( dfa ) was proposed ( peng et al . 1994 ) to analyze long - range power - law correlations in non stationary systems .
one advantage of the dfa method is that it allows the long - range power - law correlations in signals with embedded polynomial trends that can mask the true correlations in the fluctuations of a noise signal .
the dfa method has been applied to analyze dna and its evolution ( peng et al .
1992 , peng et al .
1994 ) , file editions in computer diskettes ( zebende et al .
1998 ) , economics ( mantegna & stanley 1995 ; filho et al . 2008 ) , climate temperature behavior ( talkner & weber 2000 ) , phase transition ( zebende et al . 2004 ) , astrophysics sources ( moret et al . 2003 , zebende et al . 2005 ) and cardiac dynamics ( ivanov et al.1996 , ivanov et al . 1999 ) , among others . in this paper
we propose the application of the dfa method to investigate the correlation properties presented in the ly-@xmath0 forest of quasar spectra .
the unidimensional sequence of each spectrum was used to estimate the spatial organization of the igm ( building blocks ) , which is done by looking at spatial correlations .
this work is organized as follows : in section ii , we describe the data .
we present the dfa method in section iii and the result of the dfa method applied along the line of sight to quasars in section iv .
finally , we discuss the results and conclude in section v.
the observational data used in our analysis were obtained from two different observatories ( one in the north and another in the south ) and telescopes / instruments .
the two observational programs are described below .
the first observational data set used in our analysis was obtained from the ultra - violet and visible echelle spectrograph ( uves ) mounted on the eso kueyen 8.2 m telescope at the paranal observatory in the course of the eso - vlt large programme ( lp ) `` cosmological evolution of the inter galactic medium '' ( pi jacqueline bergeron ) .
this programme has been devised to gather a homogeneous sample of echelle spectra of 18 bright qsos , with uniform spectral coverage , resolution and signal - to - noise ratio suitable for studying the intergalactic medium in the redshift range 1.7 @xmath1 z @xmath1 4.5 .
spectra were obtained in service mode and observations were spread over four periods ( two years ) during 30 nights under good seeing conditions ( @xmath1 0.8 arcsec ) .
the spectra have a signal - to - noise ratio of @xmath2 40 to 80 per pixel and a spectral resolution @xmath10 45000 in the ly-@xmath0 forest region .
details of the data reduction can be found in chand et al .
( 2004 ) and aracil et al .
( 2004 ) . in our analysis
we have only used the pixels that are located between the ly-@xmath0 and the ly-@xmath11 quasar emission lines .
medium resolution ( r @xmath2 4300 ) spectra of all z @xmath10 3 quasars discovered in the course of the dposs ( digital palomar observatory sky survey ( see e.g. kennefick , djorgovski & de carvalho 1995 ; djorgovski et al . 1999 ,
stern et al . 2000 and the complete listing of qsos available at http://www.astro.caltech.edu/@xmath2george/z4.qsos ) have been obtained with the esi ( sheinis et al .
2002 ) mounted on the keck ii 10-m telescope
. signal - to - noise ratio ( s / n ) is usually larger than 15 per 10 km/@xmath12 pixel .
these data have already been used to construct a sample of damped ly-@xmath0(dla ) systems at high redshift ( prochaska et al .
2003a ; prochaska , castro & djorgovski 2003b , ; guimares et al .
2009 ) and to study the density field around quasars ( guimares et al .
2007 ) . in total , 95 quasars have been observed , and 45 have been selected ( because of their high s / n @xmath10 25 ) to be used in our analysis . as for the uves
/ vlt sample we have used the pixels that are located between the ly-@xmath0 and the ly-@xmath11 qso emission lines .
we describe in this section the detrend fluctuation analysis ( dfa ) , wich is designed to treat data sequences with statistical inohomogeneities , such as in quasar spectra arising from non stationarity of the signal .
we treat the pixels in the ly-@xmath0 forest as a stochastic sequence x(s ) , s = 1, ... ,n ( see fig .
[ spectrum ] ) .
first , we obtain the cumulative sum of pixel series after subtracted the mean ( see fig [ flutuacao ] ) .
where\\ \bar{x } = \frac{1}{n } \sum_{s=1}^{n } x_{s } \nonumber \end{aligned}\ ] ] and n is the number of pixels after that , the profile @xmath14 was divided into equally sized box of lenght @xmath15 ( we permit the overlapping of the segments ) .
the range used for the box was @xmath16 and @xmath17 . for each segment or box
we calculated the local trend @xmath18 , that represents the non stationarity ( linear , quadratic , or polynomial ) in that box , by a least square fit of the series . finally , we subtracted the local trend @xmath18 from the integrated series @xmath14 then calculating the root - mean square ( rms ) deviation from the trend ( fluctuation ) , i. e. , the detrend fluctuation function f(n ) . @xmath19 ^ 2}\ ] ] for each box , covering the entire analyzed space series , we repeated this procedure , trying to found a relationship between the box length @xmath15 and the fluctuation @xmath20 .
if the data are power - law correlated , @xmath20 increases with @xmath15 , as a power - law , @xmath21 .
the scaling exponent @xmath0 , quantifying the degree of the long - range correlations , can be obtained from the slope of a straight line fit to @xmath22 \sim \alpha \times log(n)$ ] on a log - log plot .
the scaling exponent @xmath0 quantifying the degree of the space scale correlations , can take the following values : uncorrelated signal ( random walk ) yields @xmath23 , antipersistent correlations yields @xmath24 , and persistent correlations indicating the presence of spatial correlations yields @xmath25 .
the values @xmath26 and @xmath27 correspond to @xmath28 noise and brownian motion , respectively .
long - range negatively correlated fluctuations or changes yields @xmath29 , while the positively correlated fluctuations yields @xmath30 .
the spatial density fluctuations in the igm are nonperiodic and constitute a stochastic field . among the stochastic approaches , the dfa method described in the previous section is aimed at demonstrating the presence of scale - invariant self - similar features ( correlation , memory ) in the spatial linear density variations along the los to quasars . the dfa method was applied to the two available data sets separately . the scaling analysis results for the ly-@xmath0 forest of each esi / keck spectrum are shown in figure [ keck_scale ] .
note that the scaling variation is not the same on small and large scales .
we find that for all sequences this line was not straight but has a changing slope .
we determine 2 scaling exponents , @xmath31 and @xmath32 for the short - range and long - range correlations .
the average of all crossover points for the keck data occurs at about @xmath33 pixels .
the pixels do not have a constant size in mpc , so @xmath34 pixels can not match a single distance but is in the range @xmath35 ( comoving ) with a mean value of @xmath36 that is used hereafter . as @xmath3 is always larger than @xmath5 we do see stronger correlations on short average space scales up to @xmath36 .
we can infer from figure [ keck_scale ] that the fluctuation function presents the same pattern among the different lines - of - sight .
the scaling exponent @xmath0 does not vary significantly for different lines - of - sight .
this can be considered as a confirmation about the isotropy of the igm on large scales .
regarding the variation of @xmath0 with respect to scale , in figure [ keck_scale ] we can see that for scales n below @xmath37 pixels the scaling exponent is larger than 1.5 , reflecting highly deterministic correlations that can be related to the `` jeans lenght '' ( see bi et al . 1992 ; fang et al .
1993 ; nusser & haehnelt 1999 ; nusser 2000 ) .
the scaling exponent decays with respect to scale n , approaching an asymptotic value of @xmath38 and is characterized by the positive long - range weak correlation / persistency that can be related to the skeletonized weak clustering present in the igm on large scales . in fig .
[ keck_short ] we show the scaling exponent histogram for the short - range regime and in fig . [ keck_long ] the histogram for the long - range regime .
we can also convert the @xmath0 scaling exponent , in a fractal dimension that generalises our intuitive concepts of dimension .
@xmath39 we obtained for scales below @xmath36 ( comoving ) an average fractal dimension value of @xmath40 and for scales above @xmath36 until @xmath41 ( comoving ) an average fractal dimension value of @xmath42 .
cold dark matter models of density fluctuations predict that at scales below @xmath43 we detect values of d smaller than 2 , with @xmath44 on scales larger than @xmath45 ( de gouveia dal pino et al .
1995 ; de vega et al . 1998
; tatekawa & maeda 2001 ) .
the scaling analysis results for the lyman-@xmath0 forest of each uves / vlt spectrum are shown in figure [ uves_scale ] .
note that , like for the esi / keck data , the scaling variation on small and large scales is not identical .
we determine , as for the esi / keck sample , 2 scaling exponents , @xmath46 and @xmath47 for the short - range and long - range correlations , respectively , as the average of all scaling exponents obtained from our sample of 19 spectra .
the crossover point for the uves data occurs at about @xmath48 pixels .
however as for the esi / keck sample the pixels do not have a constant size in mpc , so @xmath49 pixels can not match a single distance but at a range of distances @xmath50 ( comoving ) .
note that the spectral resolution is not the same for both instruments esi / keck - uves / vlt which means that pixel sizes are different .
the range of turn - over distances are however nearly the same . as for the esi
/ keck sample , @xmath3 is always larger than @xmath5 implying stronger correlations on short average space scales up to @xmath51 ( comoving ) . in fig .
[ uves_short ] we show the scaling exponent histogram for the short - range regime and in fig . [ uves_long ] the histogram for the long - range regime .
the present study investigates fluctuations in the density field of the igm using an extended random walk analysis , referred to as dfa .
the advantage of the dfa method is that it can more accurately quantify the correlation property of original signals , even if masked by nonstationarity ( in the form of the trends ) compared with traditional methods such as flux decrement , power spectrum analysis , cumulative distribution function and probability distribution function .
futhermore the dfa is not sensitive to continuous level uncertainties . the dfa plots ,
that is , plots of @xmath52 vs @xmath53 exhibit the so - called `` cross - over '' phenomenon : there exists a difference in the correlation properties between the short and long - range regimes .
these @xmath54 and @xmath55 as well as the crossover point , were determined for 2 different sets of data - esi / keck uves / vlt - by the best two - line fit based on least @xmath56 squared test
. the small scale scaling exponent estimated from the esi / keck set of data , @xmath57 , and from the uves / vlt set of data , @xmath58 , are larger than 1.5 indicating positive strong spatial autocorrelation or persistency in the subsequent increases or decreases . in the long - range regime
the scaling exponents for the set of esi / keck data is @xmath59 and that from the uves / vlt set of data is @xmath60 .
this implies that on longer scales we found a weaker positive correlation or persistency than on short range scales . we can interpret this transition with scale as a transition from clumpiness to homogeneity .
the scaling exponent is identical in all directions which demonstrate the isotropy ( self - similarity ) of the igm .
this work received financial support from fapesb ( organization of the bahia , brazil , government devoted to funding of science and technology ) .
sgd was supported in part by the nsf grants ast-0407448 , ast-0909182 , and ast-1313422 .
the authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of mauna kea has always had within the indigenous hawaiian community .
we are most fortunate to have the opportunity to conduct observations from this mountain .
we acknowledge the keck support staff for their efforts in performing these observations . | we use , for the first time , the detrend fluctuation analysis ( dfa ) to study the correlation properties of the transmitted flux fluctuations , in the lyman-@xmath0 ( ly@xmath0 ) forest along the lines of sight ( los ) to qsos , at different space scales .
we consider in our analysis the transmitted flux in the intergalactic medium over the redshift range 2 @xmath1 z @xmath1 4.5 from a sample of 45 high - quality medium resolution ( r @xmath2 4300 ) quasar spectra obtained with echelle spectrograph and imager ( esi ) mounted on the keck ii 10-m telescope , and from a sample of 19 high - quality high resolution ( r @xmath2 50000 ) quasar spectra obtained with ultra - violet and visible echelle spectrograh ( uves ) mounted on the eso kueyen 8.2 m telescope .
the result of the dfa method applied to both datasets , shows that there exists a difference in the correlation properties between the short and long - range regimes : the slopes of the transmitted flux fluctuation function are different on small and large scales .
the scaling exponents , @xmath3 = 1.635@xmath4 0.115 and @xmath5 = 0.758@xmath4 0.085 for the esi / keck sample and @xmath3 = 1.763 @xmath6 and @xmath5 = 0.798 @xmath7 for the uves / vlt sample for the short and long range regime respectively .
the transition between the two regims is observed at about @xmath8 ( comoving ) .
the fact that @xmath3 is always larger than @xmath5 for each spectrum supports the common view that the universe is smoother on large scales than on small scales .
the non detection of considerable variations in the scaling exponents from los to los confirms that anisotropies can not be ubiquitous , at least on these scales . |
on july 4 , 2012 , a new particle at around 125 gev was discovered at the lhc @xcite . through measurements of the coupling property , spin and parity ,
the new particle has so far been almost consistent with the higgs boson predicted as a key boson responsible for the origin of mass in the standard model ( sm ) .
one discrepancy from the sm higgs has been , however , reported in the diphoton channel @xcite where the observed signal event is about two times larger than the sm higgs prediction .
this would imply that the observed scalar boson is a sm - higgs impostor concerning the underlying theory beyond the sm .
one such a possible impostor is the technidilaton ( td ) , a composite scalar boson , predicted in the walking technicolor ( wtc ) @xcite with an approximately scale - invariant ( conformal ) gauge dynamics and a large anomalous dimension @xmath0 .
the td is a pseudo nambu - goldstone boson for the spontaneous breaking of the approximate scale symmetry triggered by technifermion condensation and hence its lightness , say 125 gev , would be protected by the approximate scale symmetry inherent to the wtc .
thus the discovery of td would imply the discovery of the wtc .
the lhc signatures of the td were studied in a couple of recent papers @xcite .
it was shown @xcite that the 125 gev td is consistent with the currently reported diphoton signal as well as other signals such as @xmath1 and @xmath2 , etc .. it was emphasized that the td is favored by the current data thanks to the presence of extra technifermion loop corrections to digluon and diphoton couplings .
this talk summarizes the 125 gev td phenomenology at the lhc and shows a theoretically interesting possibility that the td can indeed be as light as the 125 gev boson by certain nontrivial feature intrinsic to the dynamics of wtc .
the stability of the td mass is also discussed , where it turns out that the large td decay constant plays an important role against corrections from the sm particles in a low - energy region to be relevant after the walking behavior .
we start with a review of the characteristic features of wtc including the spontaneous breaking of both chiral and scale symmetries and the mass generation of td ( sec .
[ wtc - td ] ) .
we then discuss the size of the td mass following two approaches : straightforward nonperturbative computations in the ladder approximation @xcite ( sec .
[ lad - est ] ) and a model estimate in a view of holography applied to wtc @xcite ( sec.[holo - est ] ) .
in contrast to the ladder estimate , the holographic model incorporates effects from the technigluon condensation , which turns out to play the crucial role to realize the td mass on the order of 125 gev @xcite . to make direct contact with the lhc study
, we derive a low - energy effective lagrangian @xcite obtained by integrating out technifermions , which is governed by the lightest technihadron spectra involving the td ( sec .
[ eff - lag ] ) .
the lagrangian is constructed based on nonlinear realization of the scale symmetry as well as the chiral symmetry coupled to the sm particles via the sm gauge interactions .
the td couplings to the sm particles are read off from the effective lagrangian .
we then find that the couplings take essentially the same form as those of the sm particles , except two distinguishable ingredients : the overall scale of the couplings are set by the td decay constant ( @xmath3 ) associated with the spontaneous breaking of the scale symmetry , not by the electroweak ( ew ) scale ( @xmath4 ) .
actually , @xmath3 turns out to be larger than @xmath4 from both ladder and holographic estimates .
the other crucial discrepancy comes in the couplings to diphoton and digluon , which get effects from technifermion loop contributions to be either enhanced or suppressed , depending on models of wtc . to be concrete
, we will take one - family model for the wtc to explicitly calculate those couplings .
after understanding the td coupling property from the effective lagrangian , we pay attention to the stability of the td mass against radiative corrections arising from the sm particle loops .
the large td decay constant @xmath3 then turns out to play the crucial role to keep the td mass around 125 gev without invoking heavy fine tunning , in contrast to the sm higgs case .
finally , we shall explore the lhc production and decay processes of the 125 gev td in the one - family model and estimate the signal strengths for the relevant channels to be compared with the experimental data on the higgs searches ( sec .
[ signal ] ) .
it is shown that the td signal is consistent with the currently reported data and can give a better fit than the sm higgs , notably due to the presence of extra technifermion loop corrections .
technicolor ( tc ) @xcite accommodates the ew symmetry breaking by technifermion condensation , without invoking the fundamental higgs boson , just like the quark condensation in qcd , and hence gives the dynamical explanation for the origin of mass . the original version of tc @xcite , a naive scale - up version of qcd ,
was ruled out due to the excessive flavor - changing neutral currents .
a way out of this problem was suggested under a simple assumption of the existence of a large anomalous dimension for technifermion bilinear operator @xmath5 without any concrete dynamics and concrete value of the anomalous dimension @xcite .
it was the wtc @xcite that exhibited a concrete dynamics based on a nonperturbative analysis of ladder schwinger - dyson ( sd ) equation with nonrunning ( scale invariant / conformal ) gauge coupling , @xmath6 , yielding a concrete value of the anomalous dimension , @xmath7 in the chiral broken phase .
modern version of wtc @xcite is based on the two - loop running coupling with the caswell - banks - zaks infrared fixed point @xcite , instead of the nonrunning one , in the improved ladder sd equation .
another problem of the tc as a qcd scale - up is the ew constraints , so - called @xmath8 and @xmath9 parameters .
this may also be improved in the wtc @xcite . even if wtc in isolation can not overcome this problem ,
there still exist a possibility that the problem may be resolved in the combined dynamical system including the sm fermion mass generation such as the extended tc ( etc ) dynamics @xcite , in much the same way as the solution ( `` ideal fermion delocalization '' ) @xcite in the higgsless models which simultaneously adjust @xmath8 and @xmath9 parameters by incorporating the sm fermion mass profile
. it would be better to understand the wtc through an illustration by the notion of gauge dynamics : figure [ alpha - beta ] shows a schematic view of the wtc in terms of the gauge coupling @xmath10 ( left panel ) and its beta function @xmath11 ( right panel ) . in a field theoretical sense , the walking " can be realized by an accidental balance between gluonic and fermionic contributions to the running of gauge coupling of @xmath12 gauge theory including @xmath13 fermions .
in fact , the presence of walking region implies a pseudo infrared fixed point ( @xmath14 ) , a la caswell - banks - zack infrared fixed point based on the two - loop beta function in the large @xmath15 qcd @xcite . during the walking region ( region ii in fig .
[ alpha - beta ] ) , the gauge coupling slowly reaches the critical coupling , which is slightly off from an infrared fixed point @xmath14 , @xmath16 , where the chiral symmetry is dynamically broken by technifermion condensation @xmath17 and hence technifermions get the dynamical mass @xmath18 tev , where @xmath19 denotes the technipion decay constant associated with the chiral symmetry breaking .
the walking regime ( region ii ) expands in a wide range @xmath20 : below the infrared scale @xmath21 , technifermions decouple and hence the balance with technigluon contributions gets lost , leading to the one edge of walking ( region iii ) , while above the ultraviolet scale @xmath22 tev ) the theory will be embedded into an etc ( region i ) .
( left panel ) and the beta function @xmath23 ( right panel ) .
, title="fig:",width=226 ] ( left panel ) and the beta function @xmath23 ( right panel ) .
, title="fig:",width=226 ] the dynamical mass generation of technifermion is characterized by so - called miransky scaling @xcite , tied with the conformal phase transition @xcite , @xmath24 note that this scaling property implies the wide - range walking regime above @xmath25 in region ii of fig .
[ alpha - beta ] .
the chiral condensate @xmath26 is generated to scale with the large anomalous dimension @xmath27 which solves the flavor - changing neutral current problem @xcite : @xmath28 of particular interest is the fact that the wtc possesses the ( approximate ) scale invariance ( @xmath29 for @xmath30 ) , which is spontaneously broken by the technifermion condensation / mass generation .
this implies presence of a ( pseudo ) nambu - goldstone boson ( dilaton " ) for the scale symmetry .
this is a flavor - singlet composite scalar and may be a mixture of @xmath31 bound state and techniglueball .
that is the td , technidilaton .
the td gets massive essentially due to the nonperturbative " scale anomaly : according to the dynamical mass generation in eq.([miransky ] ) , the gauge coupling @xmath10 is renormalized , starts running and hence the nonperturbative " beta function @xmath32 is generated @xcite : @xmath33 this induces the nonperturbative " scale anomaly : @xmath34 where @xmath35 denotes the dilatation current and @xmath36 the field strength of technigluon field . thus the td becomes massive due to the nonperturbative scale anomaly @xcite .
a straightforward calculation @xcite based on the ladder sd equation and the ladder ( homogeneous ) bethe - salpeter ( bs ) equation in the walking regime indicates a relatively light scalar bound state ( identified with td ) : @xmath37 for the one - family model with @xmath38 gev .
this @xmath39 is much smaller than masses of the techni - vector / axial - vector mesons on tev range , but still larger than the lhc boson at 125 gev .
this result is consistent with another calculation @xcite based on the ladder sd equation and the ladder ( inhomogeneous ) bs equation , and also consistent with other indirect computation @xcite based on the ladder gauged nambu - jona - lasinio model .
in fact , the pcdc ( partially conserved dilatation current ) relation evaluated in the ladder approximation does not allow a very light td unless the td gets decoupled with divergent decay constant @xmath3 @xcite : the pcdc relation reads @xmath40 where @xmath41 is the trace of energy - momentum tensor . to this relation , the ladder estimate gives @xmath42 ( near the conformal window ) with @xmath43 @xcite .
this simply implies that the limit @xmath44 , where the td gets light compared with the weak scale @xmath45 , can only be realized when @xmath46 , i.e. , a decoupled limit : @xmath47 as suggested earlier @xcite , however , there is a potential problem in the ladder approximation about the mass of the td .
actually , the ladder approximation totally ignores non - ladder dynamics , say , most notably the full gluonic dynamics . thus a possible way out would be to include fully _ nonperturbative gluonic dynamics_. ( also a direct estimate of @xmath3 free from the ladder approximation and without invoking the pcdc ( without referring to @xmath39 ) is necessary to give more implications of the td at the lhc . )
one such a possibility besides lattice simulations would be a holographic computation based on the gauge - gravity duality @xcite .
we shall work on a recently proposed holographic model @xcite , which is based on deformation of a bottom - up approach for successful holographic - dual of qcd @xcite .
the model describes a five - dimensional gauge theory having @xmath48 gauge symmetry , defined on the five - dimensional anti - de - sitter space with the fifth direction being compactified on a finite interval .
in addition to a bulk scalar dual to the technifermion bilinear operator @xmath49 with the anomalous dimension @xmath0 , an extra bulk scalar field dual to technigluon condensate @xmath50 is incorporated is actually necessary to properly reproduce the high energy behavior of vector / axial - vector current correlator including the gluon condensate term as predicted in the operator product expansion @xcite . ] . following the well - known holographic recipe
, one can easily calculate the scalar ( or dilatation ) current correlator and examine the lowest pole identified as the td mass to get a formula in a light td limit : @xmath51 ( the details can be found in the published paper @xcite . )
this implies that , in contrast to the ladder approximation eq.([mtd : lad ] ) , the td can be as light as the 125 gev boson by a large gluonic effect @xmath52 : @xmath53 for the one - family model with @xmath54 .
it is also interesting to note that the gluonic effect in qcd is much smaller , @xmath55 @xcite .
similarly , one can calculate the td decay constant @xmath3 by examining the pole residue of the dilatation current correlator to find a formula @xcite : @xmath56 this and eq.([holo : formula ] ) indicate that , in contrast to the ladder approximation eq.([limit : lad ] ) , a very light / massless td with the finite decay constant @xmath3 can be realized when @xmath52 goes to infinity : @xmath57 the large @xmath52 limit actually corresponds to a conformal " limit where @xmath58 : combining eqs.([holo : formula ] ) and ( [ holo : formula:2 ] ) with the pcdc relation in eq.([pcdc ] ) and calculating the technigluon condensate @xmath59 , one can evaluate the beta function as a function of @xmath52 to find that @xmath60 as @xmath61 @xcite .
thus the holographic estimate suggests that a very light td with the finite decay constant can be allowed due to the conformality tied with the nonperturbative gluonic effect @xmath52 .
though this holographic result is strong enough to indicate the presence of the 125 gev td , we would anticipate that lattice simulations will give a more conclusive answer .
below the technifermion mass scale @xmath62 tev ( see region iii in fig .[alpha - beta ] ) , the wtc can be viewed as an effective technihadron model as in the qcd case .
such an effective model will be described by a low - energy effective lagrangian based on nonlinear realization of both chiral and scale symmetries , involving the 125 gev td and the sm particles , which is most relevant for the lhc study .
the chiral / ew and scale invariant lagrangian thus takes the form @xcite @xmath63 + { \cal l}_{\rm kin}(\chi ) \ , , \label{inv : l}\ ] ] where @xmath64 is a nonlinear base of the scale symmetry , which parametrizes the td field @xmath65 with the decay constant @xmath3 and has the scale dimension 1 ; @xmath66 with the @xmath67 and @xmath68 gauge fields @xmath69 and @xmath70 ; @xmath71 denotes the scale invariant kinetic term of td and @xmath72 the usual chiral field parameterizing the ( eaten ) nambu - goldstone boson fields @xmath73 as @xmath74 ; the @xmath75 term gives the td couplings to massive weak bosons : @xmath76 as seen in eqs.([np : beta ] ) and ( [ np : sa ] ) , the scale symmetry is actually broken explicitly as well as spontaneously by dynamical mass generation of technifermions , which has to be respected also in the nonlinear realization @xcite .
such explicit breaking effects arise in the td yukawa couplings to the sm fermions , which reflect underlying etc - induced four - fermion terms , and couplings to qcd gluons and photons related to the scale anomaly in the sm gauge sector . in order to incorporate these effects into the scale - invariant lagrangian
, we introduce a spurion field @xmath8 having the scale dimension @xmath77 coupled to the sm fermions , digluon @xmath78 and diphoton @xmath79 in such a way that @xcite @xmath80 where @xmath36 and @xmath81 respectively denote the field strengths for qcd gluon and photon fields ; @xmath82 and @xmath83 are the qcd gauge and electromagnetic couplings , respectively ; @xmath84s are the beta functions only including the technifermion loop contributions .
the td yukawa coupling to the sm @xmath85-fermion arises from the first line of eq.([lag : s ] ) as @xcite @xmath86 along with scale dimension of technifermion bilinear operator @xmath87 .
the anomalous dimension @xmath27 in wtc , which is crucial to obtain the realistic mass of the sm fermions of the first and the second generations without suffering from the flavor - changing neutral current problems .
however it was known for long time that it is not enough for the mass of the third - generation sm @xmath85-fermions like @xmath88 : a simplest resolution would be the strong etc model @xcite having much larger anomalous dimension @xmath89 due to the strong effective four - fermion coupling from the etc dynamics in addition to the walking gauge coupling . here
we take @xmath90 2 , i.e. , @xmath91 , as in the strong etc model for the third - generation sm @xmath85-fermions like @xmath88 which are relevant to the current lhc data .
we see from eqs.([td : ww ] ) and ( [ td : yukawa ] ) that the td couplings to @xmath69 and @xmath92 bosons and fermions are related to those of the sm higgs by a simple scaling : @xmath93 in addition to the above scaling , the couplings to gluon and photon ( @xmath94 and @xmath95 terms in eq.([lag : s ] ) ) involve the beta functions , @xmath96 and @xmath97 , induced from @xmath98-technifermion loops @xcite .
we shall employ the one - family model as a concrete wtc setting and evaluate the betas @xmath96 and @xmath97 at the one - loop level in the perturbation -@xmath99-@xmath99 @xcite . ] : @xmath100 we thus find the scaling from the sm higgs for the couplings to @xmath78 and @xmath79 , which can approximately be expressed at around 125 gev as @xmath101 where in estimating the sm contributions we have incorporated only the top and @xmath69 boson loop contributions .
one could actually derive these td couplings directly from the ward - takahashi identities for the dilatation symmetry ( low - energy theorem ) @xcite . as seen from eqs.([scaling ] ) and ( [ g - dip - dig ] ) , once the ratio @xmath102 is fixed , the td lhc phenomenological study can be made just by quoting the sm higgs coupling properties : we may estimate @xmath3 based on the ladder approximation @xcite : the td decay constant @xmath3 can actually be related to the td mass @xmath39 through the pcdc which is analogous to the pcac ( partially conserved axialvector current ) relation for the qcd pion involving the vacuum energy density @xmath103 : @xmath104 the vacuum energy density @xmath103 is saturated by the technigluon condensation induced from the technifermion condensation , so is generically expressed as @xmath105 where @xmath106 denotes the dynamical technifermion mass and @xmath107 with @xmath108 being the number of ew doublets formed by technifermions and the number of dummy technifermions , @xmath109 , which are singlet under the sm gauges .
the overall coefficient @xmath110 is determined once a straightforward nonperturbative calculation is made .
the dynamical technifermion mass @xmath106 can , on the other hand , be related to the technipion decay constant @xmath19 : @xmath111 with the overall coefficient @xmath112 and the property of @xmath113 scaling taken into account .
the values of @xmath110 and @xmath112 may be quoted from the latest result @xcite on a ladder schwinger - dyson analysis for a modern version of wtc @xcite : @xmath114 where @xmath112 has been estimated based on the pagels - stokar formula @xcite . in that case
@xmath13 is fixed by the criticality condition for the walking regime as @xcite @xmath115 the estimated values in eqs.([kappas ] ) and ( [ criticality ] ) are based on ladder approximation which are subject to certain uncertainties up to 30% observed for the critical coupling and hadron spectrum in qcd @xcite .
we may include this 30% uncertainty in estimation of each independent factor @xmath110 , @xmath116 and the criticality condition @xmath117 .
putting these all together , we thus estimate @xmath102 as @xmath118 alternatively , using the holographic estimate in eq.([holo : formula:2 ] ) and incorporating a typical @xmath11930% correction into the holography coming from the next - to - leading order terms in @xmath120 expansion , we may estimate the td decay constant @xmath3 to get @xcite @xmath121 which is coincidentally consistent with the ladder estimate in eq.([vals ] ) .
note that the two calculations are quite different qualitatively in a sense that the ladder calculation has no massless td limit , while the holographic model including the nonperturbative gluonic dynamics does .
nevertheless , such a numerical coincidence may suggest that both models are reflecting some reality through similar dynamical effects for the particular mass region of the 125 gev td . before proceeding to the lhc phenomenology , we shall briefly remark on stability of the light td mass against radiative corrections . as a pseudo nambu - goldstone boson of scale invariance ,
the quadratic divergence is suppressed by the scale invariance for the walking regime @xmath122 ( region ii in fig .
[ alpha - beta ] ) .
the scale symmetry breaking in the ultraviolet region @xmath123 ( region i in fig . [ alpha - beta ] ) has no problem thanks to the naturalness as usual like in the qcd and the qcd - scale - up tc where the theory has only logarithmic divergences . only possible source of the scale symmetry violation
is from an effective theory for @xmath124 ( region iii in fig .
[ alpha - beta ] ) .
below @xmath125 the dominant corrections to the td mass @xmath39 come from the sm top quark loop coupling could yield a similar correction to @xmath39 at one - loop level .
this contribution , however , turns out to be negligible in magnitude compared to the top - loop correction in eq.([top - corr ] ) , due to the high suppression factor @xmath126 @xcite . ] , which can be estimated from the effective lagrangian in eqs.([inv : l ] ) and ( [ lag : s ] ) as @xmath127 where the cutoff has been set by @xmath106 . due to the large td decay constant @xmath128 ( see eq.([holo : prediction ] ) ) , this correction only gives a tiny shift to the 125 gev td mass ( note numerically @xmath129 ) : @xmath130 thus the 125 gev td mass is fully stable against the radiative corrections , in contrast to the unnatural sm higgs case .
we now discuss the 125 gev td phenomenology at the lhc based on the coupling properties derived in the previous section .
as is clear from eqs.([scaling ] ) and ( [ holo : prediction ] ) , the td couplings to the sm particles are simply suppressed by the large decay constant @xmath3 compared to the sm higgs case . as seen from eq.([g - dip - dig ] ) , however , the gluon - gluon fusion ( ggf ) and diphoton couplings can be enhanced due to extra contributions from technifermions in the one - family model which compensate the overall suppression by @xmath3 .
thus the ggf process becomes mostly dominant in the td lhc production , while other production processes such as vector boson fusion ( vbf ) and vector boson associate production ( vh ) are suppressed simply by the large td decay constant @xmath3 .
similarly , the branching fraction is almost governed by the decay to digluon which becomes comparable with @xmath131 channel for the sm higgs , while other channels such as the decay to @xmath132 and fermion pairs are suppressed .
( the td total width at 125 gev is comparable with the sm higgs one . )
more details on the production and decay properties can be found in the published papers @xcite . in order to make a direct comparison with the current lhc data @xcite
, we estimate the td signal strengths normalized to the sm higgs cross section , @xmath133 taking the one - family model with @xmath134 and @xmath135 as a benchmark , in table [ signal - strength ] we summarize the predicted signal strengths at 125 gev for each category relevant to the current higgs search at 8tev lhc . as for vbf - tag categories ,
we have taken into account about 30% contamination from the ggf process as in the case of the sm higgs .
[ signal - strength ] from table [ signal - strength ] we see that the diphoton signal strength for the ggf - tag category is slightly enhanced and can explain the currently reported excess at the lhc @xcite , while other channels in the ggf - tag categories are almost sm higgs - like , not distinguishable from those for the sm higgs .
the characteristic feature of the 125 gev td in the one - family model is seen at the vbf- and vh - tag categories , which are significantly suppressed compared to the sm higgs case , simply due to the overall suppression of the couplings by the large decay constant @xmath3 .
this will be tested in the future , though the presently observed significance on such categories are still lower than those for the ggf - tag category .
finally , we shall test the goodness - of - fit of the td with use of the current lhc data @xcite , based on the @xmath136 function : @xmath137 where @xmath138 denote the best - fit strengths for each channel reported and @xmath139 the corresponding one sigma errors .
taking @xmath140 as a free parameter so as to satisfy the theoretically expected range in eq.([vals ] ) ( or eq.([holo : prediction ] ) ) , in fig .
[ fit - afterhcp ] we plot the @xmath136 function for the 125 gev td in the one - family model with @xmath141 .
in particular , the best - fit values for @xmath142 are as follows : @xmath143 which are compared with the sm higgs case , @xmath144 , implying that the td is more favorable than the sm higgs @xmath145 .
this nice goodness of fit is due to the significant enhancement in the diphoton channel coming from the sector beyond the sm ( technifermions ) : the technifermion loop contributions as in eq.([g - dip - dig ] ) become large enough to compensate the smallness of the overall @xmath140 in eq.([vals ] ) . as a function of @xmath102 for the 125 gev td in the one - family model with @xmath141 .
the dotted straight line corresponds to the sm higgs case .
bottom panel : the predicted signal strengths in comparison with the current lhc data @xcite .
, title="fig : " ] as a function of @xmath102 for the 125 gev td in the one - family model with @xmath141 .
the dotted straight line corresponds to the sm higgs case .
bottom panel : the predicted signal strengths in comparison with the current lhc data @xcite .
, title="fig : " ]
the td is the characteristic light composite scalar in wtc .
the mass can be 125 gev , protected by the approximate scale invariance .
the td mass is also stable against the sm radiative corrections , where the large td decay constant plays an important role .
the couplings to the sm particles take essentially the same form as those for the sm higgs , except couplings to diphoton and digluon which involve a high model - dependence .
the 125 gev td in the one - family model gives the lhc signal consistent with the lhc data , notably can explain the currently reported diphoton excess .
more precise measurements in vbf and vh categories will draw a definite conclusion that the td is favored , or not .
+ _ note added _ : after the scgt 12 workshop , the atlas and cms have reported updated data in some channels for the higgs search involving @xmath146 and diphoton channels @xcite .
however , the signals in vbf- and vh - tag categories have not yet clearly been measured , which would actually be the most characteristic for the 125 gev td in the one - family model : the most significant channels with the significance over @xmath147 sigma are still only in the ggf - tag categories , as far as the amount of observed excess over the background is concerned .
see table [ signal - strength : added ] .
thus the 125 gev td in the one - family model is still consistent with the latest data .
further update on measurements in the vbf- and vh - tag categories is needed to more definitely say that is the td , or not .
[ signal - strength : added ]
i would like to thank k. yamawaki for collaborations for a couple of recent papers on the technidilaton phenomenology .
this work was supported by the jsps grant - in - aid for scientific research ( s ) # 22224003 .
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d * 70 * , 033009 ( 2004 ) . | the technidilaton ( td ) is a composite scalar predicted in walking technicolor ( wtc ) , arising as a pseudo nambu - goldstone boson associated with the spontaneous breaking of the approximate scale invariance . due to the nambu - goldstone boson s nature
, the td can be as light as the lhc boson that has been discovered at around 125 gev .
we discuss the size of the td mass and the coupling properties relevant to the lhc study .
it turns out that the td couplings to the standard model ( sm ) particles take the same form as those of the sm higgs boson , except the essentially distinguishable two ingredients : i ) the overall coupling strengths set by the decay constant related to the spontaneous breaking of the scale invariance , which is in general not equal to the electroweak scale ; ii ) the couplings to photons and gluons which can include extra contributions from technifermion loops and hence can be enhanced compared to the sm higgs case . to be concrete ,
we take the one - family technicolor model to explore the td lhc phenomenology at 125 gev .
it is shown that the td gives the signal consistent with the currently reported lhc data , notably can explain the excess in the diphoton channel , due to the extra contributions to digluon and diphoton couplings coming from the one - family technifermion loops . |
one of the most intriguing features of quantum mechanical description of physical objects consists in presence of quantum superpositions and especially of entangled states @xcite . at the very beginning of the quantum theory development such states
were found to possess quite counterintuitive ( from the classical point of view ) properties @xcite . during the 20th century
the attitude of physicists to such quantum states evolved from perceiving them as either evidences of theory incompleteness or interesting but quite useless features of the world @xcite to understanding the opportunities provided by such quantum objects for solving numerous tasks of information processing @xcite .
it has been shown that quantum no - cloning theorem @xcite provides unconditional security of quantum cryptography protocols @xcite , while using entangled states of quantum register can lead to essential speed - up of solving several classes of complicated computational tasks @xcite . from this point of view entanglement
represents an important resource for different information tasks .
on the other hand , entanglement itself requires some physical resources for its generation and , thus , can be considered as an intermediate step on the way from physical devices to accomplishing tasks of information processing . similarly to many other situations , the resources available nowadays for entanglement generation are limited , and one of the most important problems is to find methods for obtaining results as good as possible using as few resources as possible . among systems , being promising for efficient entanglement generation , optical field modes take their place due to possibility of long - distance transmission with relatively low decoherence and quite simple manipulation of the states with linear optics and photodetectors . considering optical entanglement generation
, one can divide necessary elements into two classes : quite simple elements , available `` freely '' ( linear optical devices , photodetectors not resolving photon number , classical optical states ) , and _ resources _ all other elements , being quite challenging for construction .
it is impossible to generate entanglement with the first group of elements only ( see e.g. refs .
@xcite ) , and , therefore , some resources are necessarily required . the main resource , used for entanglement generation by optical methods , is nonlinearity , either measurement - induced @xcite or provided by interaction between the field modes in some medium .
the corresponding physical resources are special detectors ( e.g. resolving photon number @xcite ) and nonlinear media respectively .
entangled states can be created also by means of linear optics from nonclassical states , which in their turn require nonlinearity for their generation .
many quantum information processing and communication tasks ( quantum cryptography , distributed quantum computation , teleportation of quantum states ) require distribution of entanglement between parties , separated by noisy medium .
for such tasks a high - quality quantum channel also becomes an important physical resource .
so , the two main resources , required for generating entanglement between distant states with optical methods , are nonlinear interaction and a quantum channel
. therefore , efficient entanglement generation corresponds in this case to creating strongly entangled states with weak nonlinear interactions and noisy quantum channels ( only such systems are available nowadays ) . in present paper
we consider weak local cross - kerr interaction as a resource for creating nonlocal nonclassical states of spatially separated optical field modes .
certain progress has already been achieved in this field of research @xcite , especially in the case of creating qubit - like entangled states . however , it remained quite challenging to create more general classes of entangled states with such limited resources .
we propose a protocol for creating wide class of qudit - type states ( including entangled states ) with arbitrary dimensionality in continuous variable ( optical ) system using weak cross - kerr nonlinearity ( as the main physical resources ) , linear beamsplitters , detectors not resolving photon numbers , and sources of coherent states .
we show that entanglement of the states , created with our protocol , can be higher than unity ( which is the limit for qubit - type states , that can be created by previously proposed methods ) and , thus , our protocol provides more effective use of limited physical resources .
this paper is organized as follows . in the next section
we discuss the main ideas of entanglement generation between distant sites when local nonlinear interaction and non - ideal quantum channel are available .
then the main operations of the proposed protocol and corresponding state transformations are presented .
section [ sec : discrim ] is devoted to discussion of the peculiarities of projecting the `` raw '' weakly entangled system state onto strongly entangled desired final state .
it is shown that parameters of the protocol are determined in the unique way by the desired final state , and corresponding relations are found . in section [ sec : special ] we demonstrate several applications of the protocol to creation of nonclassical and entangled states of optical field modes . in the last section
we prove applicability of the protocol for entanglement generation under realistic conditions by taking into account decoherence , limited efficiency and dark counts of photodetectors , and uncertainty of nonlinear coupling constants .
cross - kerr interaction itself can be used for generating entangled states starting from uncorrelated states of a pair of quantum objects .
suppose a field mode @xmath0 in a coherent state @xmath1 interacts with another system ( another optical field mode @xmath2 @xcite or an atomic system @xcite ) .
due to the interaction the phase of the coherent state amplitude @xmath3 of the mode @xmath0 is shifted by the value , proportional to the number of excitations @xmath4 of the system @xmath2 : latexmath:[\[\label{eqn27 } |n\rangle_a |\gamma \rangle_c \rightarrow |n\rangle_a effective strength of the interaction .
if the initial state of the object @xmath2 is a superposition of states with different excitation numbers ( e.g. a coherent state @xmath6 in the case of field mode ) , the final state of the considered system will be an entangled state , composed by pairwise combinations of coherent states with different phases of mode @xmath7 and number states of the system @xmath2 ( fig .
[ fig0](a ) ) .
cc * ( a ) * & + & + + * ( b ) * & + & + + * ( c ) * & + & + however , experimentally observed nonlinear interactions are quite weak @xcite : the effective nonlinearity strengthes , predicted in the most promising 4-level atomic systems with electromagnetically induced transparency on the basis of theoretical calculations and experimental data , have the order of @xmath8 @xcite . the magnitude of phase space displacement caused by such cross - kerr interaction is proportional to @xmath9 , and in general case the final state can be weakly entangled .
one of the solutions of the problem consists in effective nonlinearity enhancement by using intense fields @xmath0 : for @xmath10 the displacement magnitude can be large enough ( @xmath11 ) even for small @xmath12 @xcite .
entanglement generation gets more complicated if we take into account not only limited available nonlinearity , but also noisy medium between the sites ( fig .
[ fig0](b ) ) .
then decoherence strongly limits maximal possible amplitudes of the transmitted field @xmath0 ( @xmath13 ) , while the amplitude of field @xmath2 or the number of excitations in the atomic system is also limited by losses in local storage .
therefore , this simple scheme is not applicable for generating strongly entangled states when the sites are separated by noisy media .
hence , under realistic conditions a more sophisticated scheme , including some kind of entanglement enhancement , is required .
one way of obtaining strongly entangled quantum state is to implement entanglement distillation @xcite .
this approach requires storage of quite a large number of initial weakly entangled states and can be quite challenging .
another solution of the problem can be based on probabilistic entanglement enhancement @xcite . for this purpose one can design certain measurement ,
carried out at bob s site , with successful outcome transforming initial weakly entangled state into a strongly entangled state .
direct measurement of the state of field mode @xmath7 makes this mode inaccessible for any further use .
measurements , implemented with linear optics and photodetectors not resolving photon number on field modes , obtained by splitting the mode @xmath7 , completely determine the state of the mode and destroy entanglement .
therefore , some kind of nonlinearity is required at bob s site , too .
it is quite natural to suppose that this nonlinear interaction is the same as the one at alice s site ( see e.g. refs .
several schemes , based on probabilistic entanglement enhancement by a measurement at bob s site , have already been proposed for entangling distantly separated field modes , when effective strength of nonlinear interactions @xmath12 is equal to @xmath14 ( strong nonlinear interaction ) @xcite , and for entangling atomic qubits @xcite as well as for creating qubit - type entangled states of optical field modes @xcite , when only small nonlinearity is available . in present paper
we solve a more general task of designing the measurement scheme for creation of arbitrary qudit - type state ( including entangled states ) from a wide class of possible states in continuous variable system using weak cross - kerr nonlinearity , linear optical devices , detectors and sources of coherent states .
the set of achievable final states of the field modes @xmath2 and @xmath15 has the form of a sum of phase - correlated pairs of coherent states of the modes : @xmath16 where coefficients @xmath17 are arbitrary and can be fixed in an appropriate way for obtaining the state , most useful for certain practical applications .
we consider the following system ( see fig . [ fig1 ] ) : alice and bob posses local field modes @xmath2 and @xmath15 referred to below as main field modes ; the probe beam ( ancillary mode ) is denoted as mode @xmath0 ; mode @xmath18 is a reference field , transmitted from alice to bob immediately before ( or after ) ancillary field for decreasing influence of dephasing in the quantum channel on the final states .
main field modes , the ancillary and the reference fields are prepared in coherent states ( @xmath19 for alice s mode @xmath2 , @xmath20 for bob s mode @xmath15 , @xmath1 for the probe field @xmath0 and @xmath21 for the reference field @xmath18 ) .
the initial state of the system is therefore uncorrelated one .
local cross - kerr interaction of the modes @xmath2 and @xmath0 ( with effective strength @xmath12 the phase of a coherent state of mode @xmath2 increases by @xmath12 radians per each photon in @xmath0 ) leads to generation of correlations between the number of photons in the mode @xmath0 and the phase of the coherent state of the mode @xmath2 .
then the field @xmath0 is transmitted to bob s site through the quantum channel . in this section
we suppose for simplicity that all correlations are preserved by the channel .
after local interaction of the modes @xmath15 and @xmath0 ( the effective strength of the interaction is supposed in this section to be also equal to @xmath12 ) , taking place afterwards , the phases of the main modes @xmath2 and @xmath15 become correlated with the number of photons in the mode @xmath0 : @xmath22 where @xmath23 .
however , the correlations , generated in the system , are weak in a realistic case . for small ancillary field amplitudes @xmath24 ,
required for decreasing decoherence in the quantum channel @xcite , the entanglement between the states of the mode @xmath2 possessed by alice and the modes @xmath15 and @xmath0 possessed by bob is much less than unity : @xmath25 where @xmath26 .
as discussed in the previous section , the last stage of the protocol consists in detection of the probe beam state .
this operation should lead ( in the case of successful outcome ) to transformation of the weakly correlated 3-modes state into a strongly correlated 2-modes state of the form ( [ eqn3 ] ) .
the idea of obtaining the desired strongly correlated final state ( [ eqn3 ] ) from the state ( [ eqn1 ] ) is based on the following decomposition : @xmath27 where @xmath28 denotes the part of the system state , orthogonal to @xmath29 , and the vector @xmath29 is uniquely defined as @xmath30 thus , the transformation of the state ( [ eqn1 ] ) into the state ( [ eqn3 ] ) for arbitrary coefficients @xmath17 can be realized by successful discrimination of the state @xmath29 from a set of ancillary mode states , containing @xmath29 and a complete system of states , orthogonal to @xmath29 .
the most simple from theoretical point of view way of discriminating the state @xmath29 is implementing projective measurement described by operator @xmath31 which satisfies the following relation : @xmath32 however , implementation of such measurement without additional _ resources _ ( e.g. nonlinear interaction ) can be too complicated or impossible .
solution of this problem is discussed in the next section , and the discrimination technique , based on a special case of general class of povm measurements `` elimination '' measurements , is proposed .
an important fact that can be used for designing required discrimination protocol is that coherent states represent a natural basis for linear optical devices ( the set of coherent states is closed under linear optical transformations ) . from this point of view
, it is convenient to base the discrimination scheme on comparing the state of the probe beam @xmath0 with certain coherent states , obtained by splitting the reference mode @xmath18 .
however , coherent states are nonorthogonal .
it is this problem that leads to impossibility of implementing the discussed above projective measurement in a general case with linear optics .
an important set of measurements , implementable with linear beamsplitters and photodetectors for coherent states , is the set of `` elimination '' measurements ( see e.g. refs .
@xcite and fig .
[ fig2](a ) below ) the measurements with successful outcomes manifesting that the field mode state _ is not _ certain coherent state .
the concept of measurements with outcomes , manifesting that the input state _ is not _ certain fixed state , was proposed in refs .
@xcite as a part of unambiguous discrimination of two non - orthogonal states .
the concept of `` elimination '' measurements was generalized in ref .
@xcite for the case of discrimination between @xmath33 symmetric coherent states on a circle on phase plane with linear optical elements and photodetectors . in these papers
the system was supposed to be prepared in _
one _ of the states from a fixed _ finite _ set ( e.g. symmetric coherent states on a circle : @xmath34 , @xmath35 ) .
discrimination of one of the states ( e.g. @xmath36 ) is equivalent to _ elimination _ of all the remaining states from the fixed set ( in the considered example @xmath37 , @xmath38 ) .
considering ancillary mode states in our protocol , one faces a more general situation .
a complete set of independent states is infinite for a field mode , and the measured state does not necessarily coincide with certain basis vector , but can represent a superposition of basis vectors . therefore , complete description of state transformations , occurring when elimination measurements are carried out , requires a more rigorous operator definition of the concept of elimination measurements .
we define _ measurement , eliminating state @xmath39 , _ as any povm - type measurement ( described by povm @xmath40 , @xmath41^+ \hat a_i = 1 $ ] ) with at least one of the outcomes ( referred to in this paper as successful ) being characterized by operator , denoted in further consideration as @xmath42 , with the property @xmath43 having obtained this outcome , one can with certainty conclude that the measured state _ was not _
the state @xmath39 .
considering a set of measurements eliminating states @xmath44 , we will require ( simultaneously with eq .
( [ eqn7 ] ) for all vectors @xmath45 ) commutativity of operators , characterizing successful outcomes of the measurements : @xmath46=0.\ ] ] this condition means that successful elimination of the state @xmath47 must not destroy the result of elimination of the state @xmath45 for any pair of the states @xmath47 and @xmath45 from the considered set .
the conditions ( [ eqn7 ] ) , ( [ eqn23 ] ) lead to the following important implication , useful for designing the required discrimination scheme .
let the set @xmath48 , ... , @xmath49 describe successful outcomes of corresponding elimination measurements .
any state @xmath50 from the considered state space @xmath51 , is transformed into the state @xmath52 where contribution of @xmath53 only did not vanish .
the final state of the system differs from the state @xmath53 , but it is a completely defined state and can be transformed unitarily into @xmath53 ( in our protocol the ancillary mode is finally discarded and this transformation is not necessary ) .
therefore , one can state that successful elimination of all the basis vectors except @xmath53 leads to successful _
discrimination _ of the state @xmath53 .
generalization of the definition to the case , when several operators @xmath54 , @xmath55 , correspond to successful elimination of the state @xmath56 : @xmath57 , is straightforward : eq .
( [ eqn23 ] ) retains its form and must be valid for all @xmath58 , used instead of single operator @xmath59 .
the result , described by eq .
( [ eqn30 ] ) , also remains valid .
the described above technique can be used exactly for discrimination of the state @xmath29 of the ancillary mode @xmath0 in a special case of finite - dimensional space of input states .
suppose that the final state of the whole system ( modes @xmath2 , @xmath15 and @xmath0 ) can be decomposed using finite number of ancillary field mode states , and these states together with the state @xmath29 span @xmath60-dimensional space .
then we can choose @xmath61 such independent vectors @xmath62 , @xmath63 , orthogonal to @xmath29 , that the system @xmath64 is complete in corresponding subspace .
as shown above , discrimination of the state @xmath29 corresponds to successful elimination of the vectors @xmath62 , @xmath65 .
such finite - dimensional case can be realized , for instance , when the nonlinearity strength is equal to @xmath66 , where @xmath33 is an integer @xcite . in these special case the state of the modes @xmath2 , @xmath15 and @xmath0
after the nonlinear interactions can be represented as a sum of @xmath33 terms consisting of coherent state of the form @xmath67 of the ancillary mode @xmath0 and corresponding entangled state of modes @xmath2 and @xmath15 . discrimination of a fixed state @xmath68 ( by elimination of @xmath69 coherent states @xmath70 , @xmath71 ) maps initial weakly - entangled state onto strongly - entangled final state of the modes @xmath2 and @xmath15 . in general infinite - dimensional case , however , the state of the system can not be decomposed in such a way and the described discrimination technique can be applied approximately . for the considered state ( [ eqn1 ] ) and for small ancillary field amplitudes @xmath13 high accuracy of exploiting the discrimination technique can be achieved by restricting consideration by a space of states with limited photon numbers .
suppose the expression ( [ eqn3 ] ) for the desired final state has @xmath72 nonzero terms , i.e. @xmath73 for @xmath74 .
then eq .
( [ eqn5 ] ) for the state @xmath29 also has @xmath72 nonzero terms and this state belongs to @xmath60-dimensional subspace of states with limited photons numbers @xmath75 . according to eq .
( [ eqn1 ] ) , the probability of presence of more than @xmath61 photons in the mode @xmath0 is proportional to @xmath76 and is small for the considered system .
therefore , the state ( [ eqn1 ] ) with probability close to unity belongs to the same @xmath60-dimensional subspace as the state @xmath77 : @xmath78 where @xmath79 . if we construct a measurement , which leads to correct discrimination of the state @xmath29 for the subspace , spanned by the state vectors with photon numbers @xmath75 , the distance between the obtained state ( for the ideal system ) and the desired final state @xmath80 will have the order not greater than @xmath81 where @xmath82 is the probability of successful generation of the desired final state .
therefore , if the probability @xmath82 has the order at least @xmath83 , the error of exploiting the approximate discrimination technique will have the order @xmath84 which is much smaller than the decrease of the final state fidelity caused by non - ideality of the quantum channel .
calculations below show that this condition is fulfilled for the considered system .
thus , for generating the state @xmath85 composed by the sum of @xmath72 phase correlated pairs of coherent states of modes @xmath2 and @xmath15 , one needs to construct a scheme for elimination of @xmath61 vectors @xmath62 , @xmath65 .
the next step of designing the scheme for discrimination of the state @xmath29 is construction of the set of independent states @xmath86 in the form suitable for realizing elimination measurements with linear optical elements and photodetectors .
realization of such measurement for coherent states is known ( see e.g. ref .
@xcite ) , therefore , it is desirable that the basis states @xmath87 be coherent states @xmath88 with amplitudes @xmath89 . in this case
the orthogonality conditions have the form @xmath90 .
then the coherent states amplitudes @xmath91 can be found as @xmath61 roots of the @xmath61-th order equation @xmath92 and are uniquely defined for any given set @xmath93 .
these statements are correct in the nondegenerate case .
presence of degenerate roots of eq .
( [ eqn8 ] ) leads to linear dependence of the set @xmath94 . in this case
additional vectors must be added to the set to provide completeness .
these vectors can be constructed in the following way .
if the root @xmath95 has the multiplicity @xmath96 , then for @xmath97 holds @xmath98 on the other hand , @xmath99 eqs .
( [ eqn9])([eqn10 ] ) prove orthogonality of the vectors @xmath100 to @xmath101 for @xmath102 . instead of @xmath103 copies of the vector @xmath104
we obtain @xmath103 vectors @xmath105 , @xmath106 , that are ( i ) independent and ( ii ) orthogonal to @xmath29 .
thus , in general case the set of vectors @xmath107 , where @xmath108 and index @xmath109 enumerates distinct roots of eq .
( [ eqn8 ] ) , is the required set of @xmath61 independent vectors , orthogonal to @xmath29 .
this set of states can be constructed for any desired final state of the form ( [ eqn3 ] ) with finite number of terms and is uniquely defined for a fixed set of coefficients @xmath93 .
therefore , eq
. ( [ eqn8 ] ) provides the unique solution of the problem of generating any final state of the form ( [ eqn3 ] ) with minimal exploited resources . in the nondegenerate case discrimination of the state @xmath110
is based on quite a well known technique of eliminating coherent states ( fig .
[ fig2 ] ) .
for example , for eliminating a single coherent state @xmath111 the measured state is displaced in phase space by the magnitude @xmath112 ( the displacement is described by operator @xmath113 ) .
the displacement operator transforms coherent state @xmath114 into the vacuum state , and detection of photons in the field mode after the displacement ( fig .
[ fig2](a ) ) manifests that the measured state _ was not _
it should be noted that the considered detectors need not resolve photon numbers or be 100% efficient .
cc * ( a ) * & + & .
@xmath115 is the operator of coherent displacement with the magnitude @xmath112 . *
( b ) * scheme for elimination of a set of coherent states latexmath:[$ measurement for a single coherent state @xmath114 with the coherent displacement operator @xmath115 being effectively realized by mixing the mode @xmath0 with the reference mode @xmath117 in coherent state @xmath118 at linear beamsplitter @xmath119 . *
( d ) * scheme for elimination of coherent states @xmath120 , @xmath121 , with linear beamsplitters ( @xmath119 , ... , @xmath122 ; @xmath123 , ... , @xmath124 ) and photodetectors(@xmath125 , ... , @xmath126 ) ; reference coherent states for implementing necessary displacements in phase space are obtained by splitting reference field @xmath18 and applying phase shifts @xmath127 , ... , @xmath128.,title="fig : " ] + + * ( b ) * & + & .
@xmath115 is the operator of coherent displacement with the magnitude @xmath112 .
* ( b ) * scheme for elimination of a set of coherent states latexmath:[$ measurement for a single coherent state @xmath114 with the coherent displacement operator @xmath115 being effectively realized by mixing the mode @xmath0 with the reference mode @xmath117 in coherent state @xmath118 at linear beamsplitter @xmath119 . *
( d ) * scheme for elimination of coherent states @xmath120 , @xmath121 , with linear beamsplitters ( @xmath119 , ... , @xmath122 ; @xmath123 , ... , @xmath124 ) and photodetectors(@xmath125 , ... , @xmath126 ) ; reference coherent states for implementing necessary displacements in phase space are obtained by splitting reference field @xmath18 and applying phase shifts @xmath127 , ... , @xmath128.,title="fig : " ] + + * ( c ) * & + & .
@xmath115 is the operator of coherent displacement with the magnitude @xmath112 . *
( b ) * scheme for elimination of a set of coherent states latexmath:[$ measurement for a single coherent state @xmath114 with the coherent displacement operator @xmath115 being effectively realized by mixing the mode @xmath0 with the reference mode @xmath117 in coherent state @xmath118 at linear beamsplitter @xmath119 . *
( d ) * scheme for elimination of coherent states @xmath120 , @xmath121 , with linear beamsplitters ( @xmath119 , ... , @xmath122 ; @xmath123 , ... , @xmath124 ) and photodetectors(@xmath125 , ... , @xmath126 ) ; reference coherent states for implementing necessary displacements in phase space are obtained by splitting reference field @xmath18 and applying phase shifts @xmath127 , ... , @xmath128.,title="fig : " ] + + * ( d ) * & + & .
@xmath115 is the operator of coherent displacement with the magnitude @xmath112 . *
( b ) * scheme for elimination of a set of coherent states latexmath:[$ measurement for a single coherent state @xmath114 with the coherent displacement operator @xmath115 being effectively realized by mixing the mode @xmath0 with the reference mode @xmath117 in coherent state @xmath118 at linear beamsplitter @xmath119 . *
( d ) * scheme for elimination of coherent states @xmath120 , @xmath121 , with linear beamsplitters ( @xmath119 , ... , @xmath122 ; @xmath123 , ... , @xmath124 ) and
photodetectors(@xmath125 , ... , @xmath126 ) ; reference coherent states for implementing necessary displacements in phase space are obtained by splitting reference field @xmath18 and applying phase shifts @xmath127 , ... , @xmath128.,title="fig : " ] + elimination of a set of coherent states @xmath129 can be carried out in a similar way by splitting the field mode @xmath0 into @xmath61 modes ( fig .
[ fig2](b ) ) .
each of the obtained modes is used for eliminating one of the coherent states @xmath88 . in this case
obtaining photocounts ( `` clicks '' ) from all the detectors corresponds to successful outcomes of elimination of all the vectors @xmath130 and , thus , to successful discrimination of @xmath131 .
the displacement operators can be effectively realized by mixing the field mode @xmath0 with additional reference modes @xmath117 , ... , @xmath132 in corresponding coherent states @xmath133 , ... , @xmath134 ( prepared by splitting the reference mode @xmath18 and applying additional phase shifts ) at linear beamsplitters ( fig . [ fig2](c ) ) .
for example , for elimination of a single coherent state @xmath114 one mixes the mode @xmath0 with a single reference mode @xmath117 at linear beamsplitter @xmath119 with transmittance @xmath135 ( fig .
[ fig2](c ) ) .
if the amplitude of the reference mode coherent state equals @xmath136 and the measured state of the mode @xmath0 is @xmath137 , after mixing at the beamsplitter the modes will be in the state @xmath138 .
the obtained state of the mode @xmath0 can be used for some further operations , while the mode @xmath117 appears just in the state , required for implementing elimination measurement : the amplitude of the initial coherent state @xmath139 is displaced by magnitude @xmath112 .
additional phase factor @xmath140 is irrelevant for detection of presence of photons in the mode , and decrease of the field intensity by the factor @xmath141 influences only the probability of detecting photons and , thus , of obtaining successful elimination outcome . in an important case , when the mode @xmath0 is discarded after the elimination measurement , the efficiency of the measurement can be improved by requiring @xmath142 ( then @xmath143 and success probability is approximately the same as for the scheme in fig .
[ fig2](a ) ) .
the scheme suitable for implementing elimination measurements in general case of @xmath61 coherent states @xmath144 is shown in fig .
[ fig2](d ) .
if the measured state of the mode @xmath0 is coherent state @xmath139 , we require the states of the reference modes @xmath145 after mixing with the mode @xmath0 at beamsplitters to be coherent states @xmath146 , where @xmath147 is certain coefficient independent of the mode number @xmath148 .
these states correspond to displacement of the amplitude @xmath149 of the measured coherent state by magnitudes @xmath150 and can be used for carrying out corresponding elimination measurements .
transmittances @xmath151 of the beamsplitters @xmath152 in this case are defined in the unique way by the above requirement of obtaining correct coherent displacements . as in the case of single coherent state @xmath114
, we require the transmittance of the last beam splitter to be small : @xmath153 ( the mode @xmath0 is discarded after implementing elimination measurements ) .
the condition of dividing the amplitude @xmath149 of measured coherent state into equal parts @xmath147 between the modes @xmath145 leads to the following system of equations for the beamsplitter transmittances ( we define parameters @xmath154 by @xmath155 ) : @xmath156 solving these equations together with the requirement @xmath157 , one finds the following expressions for the transmittances of the beamsplitters : @xmath158 and coefficient @xmath147 : @xmath159 the amplitudes of the reference modes coherent states @xmath160 are also defined in the unique way by the requirement of obtaining correct coherent displacements in implemented elimination measurements .
the following recurrent system of equation can be obtained : @xmath161 where @xmath162 is the amplitude of reference coherent state , mixed to the mode @xmath0 by first @xmath148 beamsplitters .
the solution of this system of equations is @xmath163 as stated above , coherent states of reference mode @xmath145 with the required amplitudes @xmath164 can be obtained by splitting coherent state @xmath165 of the mode @xmath18 ( fig . [ fig2](d ) ) .
the transmittances @xmath166 of the beamsplitters @xmath167 and the phase shifts @xmath168 are solutions of the following system of equations : @xmath169 the system contains @xmath61 complex equations for @xmath170 real variables @xmath171 , ... , @xmath172 , @xmath127 , ... , @xmath128 , @xmath173 , @xmath174 .
the solution of the equations is quite cumbersome , and we will provide it in explicit form only for certain special cases , discussed below . in the degenerate case we need to eliminate not only coherent states , but also the states of the form @xmath175 , created from coherent states by adding fixed number of photons ( photons - added coherent states pacs ) .
we will show that elimination of pacs can be done exactly in the same way as elimination of coherent states @xmath88 . for designing a scheme , suitable for elimination of the coherent state with
one added photon , e.g. @xmath176 , it is useful to notice that when a beam with a single - photon excitation is split into two parts by a beamsplitter , the excitation can be detected in one of the two beams , but not in both of the beams simultaneously . if the mode @xmath0 , the state of which is measured , is initially in the state @xmath176 , after splitting the mode into two parts ( e.g. modes @xmath177 and @xmath178 ) we obtain a superposition state @xmath179 , where the added photon can be found in one of the modes , but never in the two modes simultaneously .
therefore , for all the terms of the superposition at least one of the modes is in coherent state @xmath180 .
if we implement measurements , eliminating the state @xmath180 , for both of the modes , two successful outcomes can never be obtained , if the measured state of the mode @xmath0 was latexmath:[$\hat c^+ outcomes of the elimination measurements correspond to _ elimination _ of the pacs with one added photon latexmath:[$\hat
c^+ would be obtained , if we tried to eliminate two coherent states @xmath114 and @xmath182 with equal amplitudes @xmath183 by the method , suitable for nondegenerate case .
elimination of a pacs with @xmath184 added photons ( e.g. @xmath185 ) can be carried out in a similar way , taking into account that when a mode with @xmath184 photons is split into @xmath186 parts , it is impossible to detect a photon in each of the @xmath186 modes simultaneously .
therefore , for elimination of the state @xmath187 one can splits the mode @xmath0 into @xmath186 modes .
when @xmath184 photons , added to coherent state @xmath111 according to the definition of the state @xmath185 , are distributed between @xmath186 modes , at least one mode appear in coherent state @xmath188 without added photons .
therefore , @xmath186 successful outcomes of elimination of coherent state @xmath188 for the @xmath186 modes can not be obtained simultaneously if the initial state of the mode @xmath0 is the state @xmath187 ( or any of the states @xmath114 , @xmath189 , ... , @xmath190 with lesser numbers of added photons ) .
thus , obtaining successful outcomes of the @xmath186 measurements , eliminating coherent state @xmath188 , corresponds to elimination of the state @xmath187 , as well as of the states @xmath114 , @xmath191 , ... , @xmath190 . as in the case , discussed in the previous paragraph
, exactly the same scheme could be used for elimination of the set of coherent states @xmath111 , ... , @xmath192 with equal amplitudes @xmath193 if the case were considered as nondegenerate .
the full algorithm of designing discrimination scheme for degenerate case can be summarized as follows . at first , @xmath61 roots @xmath150 of eq .
( [ eqn8 ] ) are found .
then the set of coherent states @xmath88 is constructed .
if the root @xmath95 has multiplicity @xmath194 , @xmath103 `` copies '' of the coherent state @xmath104 are replaced by @xmath103 independent states @xmath104 , @xmath195 , ... , @xmath196 . in the obtained set of independent states single coherent states
are eliminated by the method , discussed in the previous subsection .
sets of the states @xmath197 , @xmath195 , ... , @xmath198 with different numbers of photons , added to the same coherent state , are eliminated by carrying out measurements , eliminating coherent state @xmath199 ( with amplitude , decreased by splitting ) , for @xmath103 modes , obtained after splitting the mode @xmath0 .
therefore , @xmath103 `` copies '' of the root @xmath95 , appearing in the list of roots of eq .
( [ eqn8 ] ) , correspond in the final discrimination scheme to @xmath103-fold elimination of the coherent state @xmath104 .
it means that one need not make any difference between degenerate and nondegenerate roots of eq .
( [ eqn8 ] ) , eliminating coherent states @xmath88 as many times , as they appear in the list of roots of eq .
( [ eqn8 ] ) .
thus , the scheme , designed for discrimination of the state @xmath29 in nondegenerate case ( fig .
[ fig2](d ) ) , is also suitable for degenerate case .
quite interesting result of applicability of the same scheme for both nondegenerate and degenerate case can be given more rigorous mathematical proof on the basis of operator definition of elimination measurements ( eqs .
( [ eqn7 ] ) , ( [ eqn23 ] ) ) . as shown in appendix [ app1 ] ( see eq .
( [ eqn49a ] ) ) , transformation of the system density matrix in the case of successful outcomes of the @xmath61 measurements , eliminating coherent states @xmath88 , ( photocounts obtained from all the detectors @xmath200 ) has the form @xmath201 where density matrices @xmath202 and @xmath203 describe the system state before and after implementing elimination measurements respectively ; superoperator @xmath204 ( eq . ( [ eqn32 ] ) ) describes the part of system state transformation , which does not depend on measurement outcomes ; the sets of operators @xmath205 correspond to successful elimination of coherent states @xmath88 : @xmath206 @xmath207 ) are degenerate , i.e. that successful outcome of `` @xmath103-fold elimination '' of the state @xmath104 , corresponding to the root @xmath95 with multiplicity @xmath103 , ( or , in other words , successful elimination of @xmath103 `` copies '' of the state @xmath104 ) corresponds to elimination of the states @xmath104 , @xmath195 , ... , @xmath196 .
the successful result of `` @xmath103-fold elimination '' of the state @xmath104 is described by operator @xmath208 where @xmath209 .
the expression @xmath210 contains powers of operator @xmath211 not less than @xmath212 for @xmath213 . therefore , operator ( [ eqn52 ] ) corresponds to elimination of the states @xmath214 , @xmath215 : @xmath216 which proves the conclusion made in the previous subsection . for obtaining the expression for the final state of the main field modes @xmath2 and @xmath15 after discrimination of the state @xmath29 by elimination measurements , it is convenient to introduce `` phase - shifting '' operator @xmath217 ( it describes change of the main field modes state after cross - kerr interaction with the mode @xmath0 possessing 1 photon ) and to represent state @xmath218 ( described by eq .
( [ eqn1 ] ) ) using operator of coherent displacement with operator - type argument : @xmath219 with the following property : @xmath220 which leads to significant simplification of eq .
( [ eqn49 ] ) for the final state density matrix . as shown in appendix [ app1 ] ( eqs .
( [ eqn59 ] ) , ( [ eqn60 ] ) ) , the final state of main field modes @xmath2 and @xmath15 after elimination of all the states @xmath221 and subsequent discarding the ancillary mode @xmath0 is described by density matrix @xmath222 the obtained expression means that the distance between the desired final state and the state @xmath223 , generated by the scheme , has the order @xmath224 and is small enough to be neglected when nonideality of the system is taken into account . it should be noted that in certain cases the final states , generated when `` clicks '' were obtained not from all the detectors , can also be useful ( `` semi - successful '' results ) .
such states are described by expressions , similar to eq .
( [ eqn15 ] ) but without multipliers , corresponding to the detectors ( with numbers @xmath225 , @xmath226 , ... ) that did not produce `` clicks '' : @xmath227 this expression can be decomposed in the form , similar to the desired final state ( [ eqn3 ] ) but with lower possible degree of entanglement : @xmath228 e.g. for the case of absence of only one photocount the number of terms equals to @xmath61 ( instead of @xmath72 ) and the coefficients @xmath229 can be found as @xmath230 where @xmath231 . in the next section we provide several examples of final states that can be generated by the protocol for successful and `` semi - successful '' discrimination outcomes .
as the first example of possible applications of the protocol to nonclassical states generation we consider creation of a superposition of states of modes @xmath2 and @xmath15 with correlated photon numbers . we show that such superpositions arise quite naturally in our protocol and then use them to illustrate general formalism , developed in section [ sec : discrim ] .
as discussed above ( see eq .
( [ eqn27 ] ) ) , cross - kerr interaction correlates photon number of one of the interacting modes with the phase of coherent state of the other mode .
the state @xmath232 , obtained after cross - kerr interaction of the main modes @xmath2 and @xmath15 with the ancillary mode @xmath0 , can be considered either as a superposition , where phases of coherent states of the modes @xmath2 and @xmath15 are proportional to the number of photons in the mode @xmath0 ( eq . ( [ eqn1 ] ) ) , or alternatively as a superposition , where the phase of coherent state of the mode @xmath0 is proportional to the total number of photons in the modes @xmath2 and @xmath15 .
the latter interpretation of the state @xmath232 implies that discrimination of coherent state @xmath233 of the ancillary mode @xmath7 fixes the total number of photons in modes @xmath2 and @xmath15 to be equal to @xmath4 .
the final state @xmath85 in this case is a superposition of fock states of the modes @xmath2 and @xmath15 with the number of photons in each mode varying form 0 to @xmath4 and the total number of photons being equal to @xmath4 for each term .
mathematically this statement can be proved in the following way .
the state @xmath234 can be decomposed in the form : @xmath235 where @xmath236 is a superposition of states of the modes @xmath2 and @xmath15 with fixed total number of photons ( equal to @xmath4 ) ; function @xmath237 is defined as @xmath238 , @xmath239 ; we assume for simplicity that @xmath240 .
suppose that only @xmath61 terms are significant in the superposition ( [ eqn34 ] ) : @xmath241 for @xmath74 , @xmath242 then successful outcome of elimination of @xmath61 coherent states @xmath243 with subsequent discarding of the ancillary mode @xmath0 transforms the state @xmath244 into the following state of the modes @xmath2 and @xmath15 with correlated photon numbers , described above : @xmath245 generation of states of the form ( [ eqn105 ] ) can be described by general formalism , developed in section [ sec : discrim ] .
for this purpose we find coefficients @xmath17 , for which the general final state @xmath85 ( eq . ( [ eqn3 ] ) )
is equivalent for the desired final state @xmath246 ( eq .
( [ eqn105 ] ) ) . then coherent states amplitudes @xmath150 can be found by solving eq .
( [ eqn8 ] ) , and expressions for the parameters of discrimination scheme can be derived . the general expression eq .
( [ eqn3 ] ) for the final state of the modes @xmath2 and @xmath15 can be transformed to the following form : @xmath247 by decomposing coherent states @xmath248 and @xmath249 in terms of fock states , where states @xmath250 are defined by eq . ( [ eqn80 ] ) . in order to obtain @xmath251 , the coefficients @xmath17 must satisfy the following system of equations :
@xmath252 before solving this system , it is useful to compare it with eq .
( [ eqn8 ] ) for the amplitudes @xmath150 and to notice , that if coefficients @xmath17 satisfy eq .
( [ eqn107 ] ) , @xmath61 complex numbers @xmath253 , @xmath254 , apparently represent the @xmath61 roots of eq .
( [ eqn8 ] ) .
then , coefficients @xmath17 are defined in the unique way ( except for overall normalization constant ) by the complete system of roots and are equal to @xmath255 for example , if the desired final state is the following one @xmath256 coefficients @xmath17 must be equal to @xmath257 , @xmath258 , @xmath259 ( for unnormalized state ) . amplitudes of the coherent states @xmath88 , eliminated in discrimination scheme , are equal to @xmath260 and @xmath261 in this case . according to eq .
( [ eqn35 ] ) , transmittances of the beamsplitters @xmath119 and @xmath262 are equal approximately to @xmath263 ( for @xmath264 ) and @xmath265 .
the amplitudes of the reference coherent states , defined by eq .
( [ eqn75 ] ) , are @xmath266 and @xmath267 . solving the system of equations ( [ eqn76 ] ) , one finds @xmath268 , @xmath269 , @xmath270 . for coefficients @xmath271 ( eq .
( [ eqn26 ] ) ) , characterizing final state in the case of `` semi - successful '' outcomes of discrimination when the desired final state for successful outcome is described by eq .
( [ eqn109 ] ) , one obtains the following expressions : @xmath272 , @xmath273 , @xmath274 , @xmath275 .
the final state , generated when `` click '' was obtained from detector @xmath276 , is approximately a vacuum state : @xmath277 while the state , generated when `` click '' was obtained from detector @xmath125 , belongs to the class of states , described by eq .
( [ eqn105 ] ) : @xmath278 and , therefore , can be useful for certain applications .
another group of examples represents states of the form eq .
( [ eqn3 ] ) with maximal entanglement , which is possible for a scheme with fixed number of photodetectors @xmath61 ( and , therefore , with fixed number of terms in the expression ( [ eqn3 ] ) for the final state @xmath85 ) . in the most simple case of schemes with 1 detector ( @xmath279 ) the coefficients @xmath17 in eq .
( [ eqn3 ] ) , maximizing the final entanglement , can be found analytically as @xmath280 where for simplicity we consider unnormalized final state .
additional condition , required for maximization of entanglement in this case , is @xmath281 ( for simplicity we will assume without loss of generality that @xmath282 ) .
the final state of the system is approximately a bell state @xmath283 is the orthonormal basis for the states of the modes @xmath2 and @xmath15 : @xmath284 consists of the only state @xmath114 with the amplitude @xmath285 , defined by eq .
( [ eqn8 ] ) .
the transmittance of the beam splitter @xmath119 ( fig . [ fig2](c ) ) equals @xmath286 , and the amplitude of the reference coherent state is @xmath287 .
for the scheme with two detectors ( @xmath288 ) the coefficients @xmath17 , providing maximal entanglement , can be found analytically for systems with @xmath289 and @xmath290 in two limiting cases : @xmath291 ( low distinguishability of main field modes coherent states with and without phase shift equal to @xmath12 : @xmath292 ) and @xmath293 ( high distinguishability : @xmath294 ) . for @xmath291 the final entanglement is maximal for @xmath295 the final state of the system is @xmath296 are orthonormal basis vectors for the mode @xmath2 and the basis vectors @xmath297 for the mode @xmath15 are defined in a similar way ( with @xmath298 being replaced by @xmath299 ) ; coefficients @xmath300 are determined by the condition of orthonormality of the system of basis vectors .
the final state ( [ eqn14 ] ) possesses entanglement @xmath301 , which is higher than the maximal value , achievable for a pair of qubits .
in this case the coherent states @xmath302 and @xmath303 , exploited in the detection scheme , possess close amplitudes @xmath304 .
transmittances of the beamsplitters @xmath119 and @xmath262 are equal approximately to @xmath263 ( for @xmath264 ) and @xmath305 ; amplitudes of the reference coherent states are @xmath306 and @xmath307 . the parameters of discrimination scheme , defined by eq .
( [ eqn76 ] ) , are equal to @xmath308 , @xmath309 , @xmath270 . in the opposite
limiting case @xmath310 ( such condition is satisfied simultaneously with @xmath289 in the systems with intense fields @xmath2 and @xmath15 ) entanglement reaches the bound for 3-level system @xmath311 when the parameters are @xmath312 the final state in this case has the form @xmath313 are defined by eq .
( [ eqn112 ] ) above .
amplitudes of coherent states @xmath314 and @xmath315 are equal to @xmath316 .
the transmittances of the beamsplitters @xmath119 and @xmath262 and the amplitudes @xmath317 , @xmath318 of reference modes coherent states are the same functions of the amplitudes @xmath319 and @xmath320 as in the previously discussed limiting case . solving the system of equations ( [ eqn76 ] ) , one can find @xmath321 , @xmath309 , @xmath322 . for intermediate values of distinguishability ( @xmath323 ) , as well as for greater numbers of detectors ( @xmath324 ) , optimal coefficients
@xmath17 can be found numerically .
the values of maximally possible entanglement for schemes with fixed number of detectors are shown in fig .
[ fig3 ] ( solid lines ) .
one can see that the maximal possible value of entanglement grows with increase of the detectors number @xmath61 , and in certain cases it may be considered as more effective use of fixed resources ( nonlinear interaction , quantum channel ) than can be achieved in schemes with qubit - type entanglement . .
solid lines : maximal entanglement , possible for generation in the scheme with fixed number of photodetectors @xmath61 : @xmath279 ( 1 ) , @xmath288 ( 2 ) , @xmath325 ( 3 ) . dashed lines ( 2a , 2b ) : entanglement of the final state , generated by the scheme with @xmath288 detectors with optimized coefficients @xmath17 in `` semi - successful '' case ( one photocount instead of two
; entanglement does not depend on the number of the detector , which `` clicked '' ) .
dot - dashed lines ( 3a , 3b , 3c ) : final state entanglement for @xmath325 and 1 absent photocount .
dotted lines ( 3d , 3e , 3f ; line 3f coincides with the solid line 1 ) : final entanglement for @xmath325 and 2 absent photocounts . ]
[ fig3 ] also illustrates entanglement of final states , generated by these schemes for `` semi - successful '' outcomes ( obtaining photocounts from lesser number of detectors ; dashed , dotted and dot - dashed lines in fig .
[ fig3 ] ) .
these final states possess non - zero entanglement and in certain cases can also be useful for solving information processing tasks .
for example , the scheme with @xmath325 detectors , optimized for obtaining maximal entanglement in the case of successful discrimination outcome , in the case of two absent photocounts can also produce maximally entangled state from the space of states @xmath85 with 2 non - zero terms ( line 3f in fig .
[ fig3 ] ) .
in previous sections we assumed for simplicity that the quantum channel and photodetectors are ideal . in order to prove realizability of the proposed entanglement generation method in realistic situations we discuss influence of system nonideality on the fidelity of obtaining final state . in real system decoherence and dephasing
accompany all the stages of the protocol : implementation of nonlinear interaction , transmission of the probe beam through the quantum channel , storage of main modes @xmath2 and @xmath15 in local resonators .
all these factors can be taken into account by solving corresponding master equations @xcite . however , for the system , considered in our paper , influence of some of the factors on the fidelity of final state generation is supposed to be small .
therefore , for the purpose of simplifying further description , we take into account only the following factors that can limit applicability of our protocol : 1 .
[ nonid1 ] decoherence of modes @xmath2 and @xmath15 during cross - kerr interaction with probe beam @xmath0 ( decoherence of the mode @xmath0 is assumed to have negligible effect due to much smaller amplitude of the probe beam : @xmath326 inaccuracies in the nonlinearity values of the used kerr media ( we assume that effective strengthes of nonlinear interactions carried out by alice and bob are equal to @xmath327 and @xmath328 respectively and differ from the value @xmath12 used in the scheme optimization ) ; 3 .
[ nonid3 ] decoherence caused by nonideality of local resonator at alice s site ( bob s resonator is not used for storing part of an entangled state for a long time , and its nonideality is supposed to effect the final state fidelity negligibly ; dephasing in the resonators is assumed to be small due to controllable laboratory conditions ) ; 4 . [ nonid4 ] decoherence and dephasing in the quantum channel ; 5 . [ nonid5 ] limited efficiency ( probability of detecting a photon , present in the field mode , equals @xmath329 ) and dark counts of photodetectors ( obtaining photocount with probability @xmath330 when the mode is in the vacuum state ) .
for describing nonideality of the system we consider four stages of the protocol separately and find ( super-)operators , describing difference between the states , obtained in ideal and nonideal systems .
it should be noted that operator , transforming one fixed state into another fixed state ( ideal state into nonideal one in the considered case ) , is not defined in the unique way : its action on states from orthogonal space can be arbitrary . in further consideration
we try to choose operators , acting on the main modes only ( but not on the ancillary one ) , from sets of equivalent operators , transforming ideal density matrix into the nonideal one .
then the final state after implementing all the stages of the protocol is expected to be presented in the form of certain superoperator , acting on the ideal final state @xmath331 of the main modes @xmath332 and @xmath15 .
the first stage of the protocol is cross - kerr interaction of modes @xmath2 and @xmath0 .
we describe this nonlinear interaction in nonideal case by the following master equation : @xmath333 + \kappa_1
\hat l ( \hat a ) \rho,\ ] ] where @xmath334 + \left [ \hat x , \rho \hat x \right]$ ] . as discussed above ( item [ nonid1 ] in the list of nonideality types ) , the only kind of nonideality taken into account by eq .
( [ eqn61 ] ) is decoherence of the mode @xmath2 . assuming that the duration of interaction is @xmath335
, one can characterize the nonlinear interaction by effective strength @xmath336 and relative loses rate @xmath337 ( @xmath338 , where @xmath339 and @xmath340 are beam intensities before and after the interaction ) . in the ideal case ( @xmath341 ) state transformation due to discussed cross - kerr interaction
is described by unitary operator @xmath342 the initial uncorrelated state latexmath:[$|\alpha\rangle_a
|\beta\rangle_b where the phase of coherent state of the mode @xmath2 is proportional to the number of photons in the mode @xmath0 : @xmath344 transformation of the system state in the nonideal case can be found by solving the master equation eq .
( [ eqn61 ] ) with the initial condition @xmath345 , where @xmath346 is the initial uncorrelated density matrix ( initial amplitudes @xmath347 , @xmath348 , @xmath349 of coherent states in the nonideal case must be larger that the amplitudes @xmath298 , @xmath299 , @xmath3 that are expected to characterize final state ) .
the solution can be found by representing the density matrix of the modes @xmath2 and @xmath0 in the form @xmath350 which is preserved during evolution . substituting this decomposition into eq .
( [ eqn61 ] ) and solving the resulting system of differential equations , one can obtain the following expressions for the quantities @xmath351 and @xmath352 at the end of the considered stage of the protocol : @xmath353 @xmath354 where smallness of nonideality is assumed for simplicity of derived expressions .
the exponential factor in eq .
( [ eqn89 ] ) describes influence of kerr medium nonideality on the state , obtained after the interaction . for characterizing transition from the ideal state eq .
( [ eqn114 ] ) to the nonideal one the following superoperator , acting in the state space of the mode @xmath2 , can be chosen from the class of equivalent operators , describing this state transformation : @xmath355 this superoperator adds small phase shift to the coefficients before coherent states of the mode @xmath2 and decreases non - diagonal elements of the density matrix .
another factor , which influences fidelity of the final state generation but is not connected with nonideality of the kerr medium itself , is deviation of the nonlinearity effective strength @xmath356 from its expected value @xmath12 , used during optimization of the discrimination scheme parameters .
this factor can be accounted for by introducing superoperator @xmath357 which provides additional phase shift to coherent states of the mode @xmath2 .
the second stage of the protocol consists in transmission of the ancillary field from alice to bob . at the same time
the mode @xmath358 , already correlated with the ancillary mode @xmath0 , is stored at alice s site .
these two modes interact with the environment independently , and corresponding kinds of nonideality are considered separately .
decoherence of the mode @xmath2 in nonideal local resonator is described by the following master equation : @xmath359 if duration of this stage is equal to @xmath360 , relative losses rate equals to @xmath361 . the solution of eq .
( [ eqn116 ] ) can be found in the way , similar to the one used for the previous stage of the protocol .
the amplitude of coherent states of the mode @xmath2 @xmath362 after this stage of the protocol must be equal to its final value @xmath298 .
the influence of decoherence in alice s local resonator on the state of the system can be described by the superoperator @xmath363 transforming the system state in the same way as @xmath364 .
interaction with the environment of the ancillary mode @xmath0 during the second stage of the protocol is described by master equation @xmath365 where the first and the second terms describe decoherence and dephasing of the mode @xmath0 respectively ( see item [ nonid4 ] in the list of nonideality factors ) . for characterizing this type of system nonideality
one can introduce relative losses rate @xmath366 and mean phase error @xmath367 .
due to commutativity of @xmath368 and @xmath369 ( in the sense that @xmath370 ) , the master equation eq .
( [ eqn62 ] ) can be divided into two independent parts , describing decoherence and dephasing
. state transformation because of decoherence has the form : @xmath371 dephasing of the mode @xmath0 transforms the system state as @xmath372 as stated above , for certain simplification of further consideration it is useful to choose superoperators , acting on the main field modes only , from the set of equivalent superoperators , describing transition between ideal and nonideal case . for this purpose
we take into account that in the expression ( [ eqn114 ] ) for the ideal system state number states @xmath373 of the ancillary mode appear in pairs with coherent states @xmath374 .
therefore , decrease of non - diagonal density matrix elements in the basis of fock states of the mode @xmath0 is equivalent to corresponding decrease of non - diagonal elements for the mode @xmath2 in the basis of coherent states . in a similar way , discrete changes of photon number in the mode @xmath0 , caused by energy losses in the quantum channel and described by eq .
( [ eqn65 ] ) , are equivalent to corresponding discrete changes of phase of the mode @xmath2 .
after certain mathematical calculations , one can show that the difference between ideal and nonideal states , caused by decoherence and dephasing of the mode @xmath0 , can be described by superoperators @xmath375 and @xmath376 respectively .
the third stage of the protocol is cross - kerr interaction of modes @xmath15 and @xmath0 , described by the following master equation : @xmath377 + \kappa_3 \hat l ( \hat b ) \rho,\ ] ] and characterized by effective nonlinearity strength @xmath378 and relative losses rate @xmath379 ( we will assume for simplicity that @xmath380 ) , where @xmath381 is the duration of the interaction . in the ideal case
this nonlinear interaction is described by operator @xmath382 with the obtained state latexmath:[$\hat u_{bc } \hat u_{ac } @xmath232 ( see eq .
( [ eqn1 ] ) ) . for nonideal system , master equation eq .
( [ eqn63 ] ) can be solved exactly in the same way as eq .
( [ eqn61 ] ) .
the superoperator , describing transition between ideal and nonideal cases , has the form @xmath384 and , similarly to @xmath385 , adds small phase shift to the coefficients before coherent states of the mode @xmath15 and decreases non - diagonal elements of the density matrix .
deviation of the nonlinearity effective strength @xmath386 from its expected value @xmath12 can be accounted for by introducing the following superoperator , describing additional phase shift to coherent states of the mode @xmath15 : @xmath387 the last stage of the protocol is discrimination of the state @xmath29 of the mode @xmath0 at bob s site .
this stage includes operations on the ancillary mode @xmath0 only and does not influence directly modes @xmath2 and @xmath15 ( their state is transformed due to previously generated correlations with the ancillary mode ) .
all the superoperators @xmath385 , @xmath388 , @xmath389 , @xmath390 , @xmath391 , @xmath392 , @xmath393 , introduced for describing nonideality of the three preceding stages of the protocol , act on the state spaces of the mode @xmath2 and @xmath15 .
therefore , they must commute with any superoperators , characterizing the last stage of the protocol , and can be considered as acting _ after _ implementation of nonideal discrimination measurement . for such consideration the input state of the discrimination scheme is the state @xmath234 , defined by eq .
( [ eqn1 ] ) . for the ideal system , obtaining successful outcome of all the elimination measurements , followed by discarding of the mode @xmath7 ,
transforms the input weakly entangled state @xmath232 into the desired final state @xmath394 ( see eqs .
( [ eqn56 ] ) , ( [ eqn15 ] ) ) .
probability of this successful outcome equals @xmath395 of registering photons see item [ nonid5 ] in the list of types of system nonideality ) leads to decrease of probability of obtaining successful discrimination outcome , effectively reducing fraction @xmath147 of the coherent state amplitude of the ancillary mode , interacting with photodetectors , by factor @xmath396 : @xmath397 .
then one - run success probability for nonideal detection scheme is equal to @xmath398 dark counts of photodetectors lead to mixing density matrices , characteristic to `` semi - successful '' outcomes , to the final density matrix , corresponding to successful elimination of all the states @xmath88 .
then , according to eqs .
( [ eqn56])([eqn26 ] ) , successful discrimination of the state @xmath29 by the scheme with nonideal photodetectors transforms the state @xmath399 into the following mixed state : @xmath400 where @xmath148-th term corresponds to presence of @xmath401 dark counts . summarizing the results concerning discussed types of system nonideality
, we can express the density matrix of the final state of the modes @xmath2 and @xmath15 in the following form : @xmath402 this expression can be simplified by taking into account that coherent states of the modes @xmath2 and @xmath15 posses correlated phases in all terms of the expression for the density matrix @xmath403 ( eq . ( [ eqn97 ] ) ) and
appear only in groups of the form @xmath404 or @xmath405 .
therefore , superoperators @xmath406 , @xmath389 , @xmath407 , @xmath408 act at the system state in the same way : they add small phase shifts to the coefficients @xmath17 ( or @xmath409 ) and decreases non - diagonal elements of the density matrix . due to commutativity of the superoperators , they can be collected in a single superoperator @xmath410 transforming pairs of coefficients @xmath411 of the state @xmath412 ( as well as pairs of coefficients @xmath413 with the similar meaning , defined by eq .
( [ eqn26 ] ) ) in the following way : @xmath414 where @xmath415 is a phase difference per photon and @xmath416 describes decay of non - diagonal elements of density matrix . the first term in the exponent of eq .
( [ eqn85 ] ) corresponds to changing phase of coefficients @xmath17 and can be compensated by corresponding changes in the detection scheme ( by replacing @xmath150 by @xmath417 in expressions for the scheme parameters ) .
therefore , only the second term of the exponent is essential for estimation of the deviation of the nonideal final state from the ideal one . finally , expression ( [ eqn77 ] ) for the density matrix , obtained in for nonideal system , can be rewritten using the notations of eq .
( [ eqn22 ] ) in the form @xmath418 where @xmath419 . in further consideration
we assume that all types of nonideality , present in the system , are weak enough and the fidelity is close to unity ( such systems are most useful from the practical point of view ) .
then the density matrix , defined by eq .
( [ eqn79 ] ) , is approximately equal to @xmath420 where notation @xmath421 is introduced for the superoperators ; only the leading order of small parameters , characterizing nonideality of the system , is taken into account . according to the standard definition , the fidelity of generating the desired final state @xmath85 equals @xmath422 where @xmath423 is the actual final state of the main field modes @xmath2 and @xmath15 , defined by eqs .
( [ eqn79 ] ) , ( [ eqn74 ] ) . using eqs .
( [ eqn74 ] ) , ( [ eqn83 ] ) and carrying out quite straightforward mathematical calculations , one can obtain the following expression for the fidelity of final state generation : @xmath424 where @xmath425 . for further consideration it is convenient to introduce unnormalized states @xmath426 , which are useful , for example , when exponent is decomposed in eq .
( [ eqn85 ] ) .
then it is quite easy to show that @xmath427 where we suppose that the term proportional to @xmath428 vanishes due to correct phase compensation .
representing states of the form @xmath429 and @xmath430 as @xmath431 and decomposing exponents in power series in this expression , one can simplify the term in the sum in eq .
( [ eqn98 ] ) , corresponding to deviations of nonlinearity strengthes from their expected value @xmath12 : @xmath432 analytical expression for the remaining term in the sum can be found in two limiting cases : @xmath433 for @xmath291 and @xmath434 for @xmath293 .
( [ eqn98 ] ) , ( [ eqn99 ] ) , ( [ eqn100])([eqn16 ] ) provide the expression for the final state generation fidelity for any desired final state @xmath85 described by eq .
( [ eqn3 ] ) . further simplification of the derived above equations for the final state fidelity can be carried out in special cases , considered in section [ sec : special ] .
we discuss the states with maximal entanglement , possible for a scheme with fixed number of detectors ( @xmath279 and @xmath288 ) . on the basis of explicit expressions for the fidelity of such states generation we find conditions , that must be imposed on the system parameters in order to obtain sufficiently high fidelity of final state generation . for most of physical systems , suitable for implementation of the protocol , assumptions that @xmath289 and @xmath435 are valid .
in this paper we discuss analytical results obtained under these assumptions only ( however , the opposite limiting case @xmath293 can also be described analytically ) . for maximally entangled state , generated by the scheme with @xmath279 detector ( eqs .
( [ eqn11 ] ) , ( [ eqn12 ] ) ) , we obtain @xmath436 @xmath437 and @xmath438 where @xmath439 are relative inaccuracies of the nonlinear interaction strengthes ; we assumed for simplicity that @xmath290 and @xmath440 .
for the scheme with @xmath288 detectors and coefficients @xmath17 described by eq .
( [ eqn13 ] ) the form of eqs .
( [ eqn101])([eqn103 ] ) remains the same , but expressions in the right hand side of eqs .
( [ eqn101 ] ) , ( [ eqn102 ] ) get numerical factor 2 .
the finally obtained expression for decrease of the final state fidelity contains 6 distinct terms , corresponding to different types of processes in the system : eq .
( [ eqn101 ] ) corresponds to 3 terms , proportional to @xmath441 , @xmath442 and @xmath443 ( see eq .
( [ eqn87 ] ) for @xmath444 ) ; eq .
( [ eqn102 ] ) and eq .
( [ eqn103 ] ) provide expressions for the terms , describing nonlinearity strength inaccuracies and nonideality of photodetectors respectively ; eq .
( [ eqn90 ] ) corresponds to decoherence of the mode @xmath0 that can be described by effective discrete phase errors in the mode @xmath2 . in order to estimate parameters values , suitable for final state generation with sufficient fidelity ,
we require each of the discussed 6 terms to be not greater than some small value @xmath445 , @xmath446 ( then the fidelity will be not less than @xmath447 ) .
the obtained 6 inequalities can be used for finding 6 independent system parameters . for this purpose
we divide parameters , describing the system , into four groups : 1 .
parameters @xmath330 , @xmath396 , @xmath448 characterize exploited `` local '' equipment ( photodetectors , maximal field intensities providing small decoherence during local operations ) and are supposed to be fixed by characteristics of existing equipment ; in numerical estimations we assume that dark count probability has the values @xmath449 when detectors efficiency equals @xmath450 and @xmath451 for @xmath452 ( such values can be achieved for ingaas / inp photodetectors @xcite ) ; we also assume that @xmath453 ; 2 .
parameters @xmath12 , @xmath454 , @xmath455 , @xmath442 characterize local cross - kerr interaction ; we use the inequalities to estimate these parameters values and to find out whether such nonlinear interaction can be realized experimentally ; 3 .
parameters @xmath456 , @xmath441 , @xmath443 characterize properties of the quantum channel and local resonator and determine maximal distance of entanglement generation ; 4 . the ancillary field amplitude @xmath457 can be changed and is chosen so as to provide maximal success probability for sufficiently high fidelity of the final state generation .
therefore , the discussed inequalities , providing sufficient fidelity , can be expressed in the following way ( for @xmath279 ; for @xmath288 the conditions are the same except for numerical factor 1/2 in conditions 2 , 3 , 4 , 6 ) : @xmath458 the first of the conditions limits acceptable losses in the quantum channel .
this limitation is fundamental for optical methods of information processing when dark counts of photodetectors are present ( see e.g. comments in ref .
for instance , for the considered above parameters and the desired fidelity @xmath459 the maximal acceptable attenuation of the channel is limited by values @xmath460 , which for optical fiber with attenuation 0.20 db / km correspond to maximal distances about @xmath461 .
however , it should be noted , that entanglement generation at such distances requires quite long storage of the field @xmath2 in alice s local resonator . the value of the resonator finesse , required for preserving sufficient state fidelity and defined on the basis of the second condition of eq .
( [ eqn21 ] ) , is about @xmath462 in this case .
even greater values have already been predicted theoretically for crystalline whispering gallery mode resonators @xcite .
experimentally demonstrated high - quality resonators are characterized by values up to @xmath463 @xcite . therefore , we believe that the protocol will be more suitable for efficient entanglement generation when the best available quantum channel connecting alice s and bob s sites is lossier than optical fiber .
the third condition provides lower bound on the nonlinearity value . for @xmath464 and the considered above parameters the minimal nonlinearity strength is @xmath465 .
such values has already been predicted in existing systems for the case of precise radiation focusing @xcite . it should be noted , that not only nonlinearity strength , but also acceptable signal attenuation during cross - kerr interaction is limited ( the fourth condition of eq .
( [ eqn21 ] ) leads to requirement @xmath466 ) . the fifth condition of eq .
( [ eqn21 ] ) limits maximal probe beam intensities and determines the maximal possible one - run success probability for the protocol , described by eq .
( [ eqn82 ] ) . for the protocol with @xmath279 detector
the success probability is sufficiently large for all losses values not exceeding the limit determined by the first condition of eq .
( [ eqn21 ] ) ( fig .
[ fig4 ] ) . for @xmath467 generation of the desired final state can be implemented without too large number of ancillary field transmissions for losses not more than approximately 14 db ( which correspond to the distances up to 70 km in optical fiber ) .
cc * ( a ) * & + & on the relative losses rate @xmath456 for the protocol with @xmath61 photodetectors for fixed fidelity of final state generation @xmath459 : @xmath279 ( 1 ) , @xmath288 ( 2 ) .
dotted line corresponds to the limit of entanglement generation because of dark counts of detectors . *
( b ) * dependence of one - run success probability @xmath82 on the desired fidelity @xmath468 for the protocol with @xmath61 photodetectors and different losses rates @xmath456 : @xmath279 , @xmath469 ( 1 ) , @xmath279 , @xmath470 ( 2 ) , @xmath288 , @xmath469 ( 3 ) , @xmath288 , @xmath470 ( 4).,title="fig : " ] + + * ( b ) * & + & on the relative losses rate @xmath456 for the protocol with @xmath61 photodetectors for fixed fidelity of final state generation @xmath459 : @xmath279 ( 1 ) , @xmath288 ( 2 ) .
dotted line corresponds to the limit of entanglement generation because of dark counts of detectors . *
( b ) * dependence of one - run success probability @xmath82 on the desired fidelity @xmath468 for the protocol with @xmath61 photodetectors and different losses rates @xmath456 : @xmath279 , @xmath469 ( 1 ) , @xmath279 , @xmath470 ( 2 ) , @xmath288 , @xmath469 ( 3 ) , @xmath288 , @xmath470 ( 4).,title="fig : " ] + + the maximal acceptable relative inaccuracies of nonlinearity strengthes @xmath471 , @xmath472 , defined by the last condition of eq .
( [ eqn21 ] ) , are equal to 0.09 for @xmath279 and to 0.06 for @xmath288 .
such parameters values can be achieved in real systems , and , therefore , our calculations prove applicability of the protocol for entanglement generation between sites , separated by lossy media , using contemporary experimental equipment .
to summarize , in the present work we have proposed a protocol for creating a wide class of qudit - type states ( including entangled states ) with arbitrary dimensionality in continuous variable system using weak cross - kerr nonlinearity , linear beamsplitters , detectors not resolving photon numbers , and sources of coherent states .
the method of entanglement generation is based on using an ancillary field mode , transmitted from alice s site to bob s one through lossy quantum channel .
weak nonlinear interaction of the mode with the main field modes possessed by alice and bob leads to creation of a weakly entangled 3-modes state .
the main problem , solved in our work is designing a scheme for the ancillary mode state measuring leading to probabilistic entanglement enhancement and transforming the `` raw '' weakly correlated state into highly entangled final one .
the found povm measurement is shown to be implementable with linear optics and photodetectors , not resolving photon numbers , on the basis of elimination measurements .
the equation , defining parameters of the detection scheme for a given desired final state in a unique way , is also derived in our paper .
our calculations prove applicability of the proposed protocol in the case of realistic photodetectors with limited efficiency and dark counts , nonlinear kerr interaction with decaying modes , uncertainty of coupling constants , and lossy quantum channel .
it has been shown that the protocol can be used for creating quantum states with entanglement higher than unity and , therefore , in certain cases corresponds to more effective use of resources than can be achieved for protocols based on entangling qubit systems .
the fidelity of final state generation @xmath459 can be achieved when a quantum channel with losses rate up to @xmath460 is available ( it corresponds to distances up to 140 km for optical fiber ) .
required cross - kerr nonlinearity is @xmath473 and can be created using contemporary equipment .
the work has been supported partially by the european commission via project `` engineering quantum information in nanostructured diamond '' .
here we provide mathematical description of system state transformation when measurements , eliminating coherent states @xmath474 , are implemented . the considered measurement scheme is shown in fig .
[ fig2](d ) .
the mode @xmath0 is mixed at linear beamsplitters with @xmath61 reference modes @xmath475 , prepared in coherent states @xmath476 by splitting the initial coherent state of the mode @xmath18 .
then photodetectors @xmath200 determine presence of photons in the modes @xmath145 .
let the state of modes @xmath2 , @xmath15 and @xmath0 before elimination measurements be described by density matrix @xmath202 .
taking into account that coherent states represent a natural basis for describing linear optical transformations , it is convenient to decompose the input density matrix in terms of coherent states of the mode @xmath0 @xmath477 where @xmath478 is an operator - valued function of variable @xmath149 ( acting as an operator on the modes @xmath2 and @xmath15 ) , analogous to glauber function of one - mode field . the state of the expanded system , composed by the main modes @xmath358 and @xmath15 , the ancillary mode @xmath0 and reference modes @xmath145 , after mixing the ancillary mode @xmath0 with reference modes @xmath145 at beamsplitters is described by the following density matrix : using eq .
( [ eqn39 ] ) one can represent the density matrix ( [ eqn38 ] ) in the form @xmath482 where latexmath:[$|\psi(\gamma_x)\rangle_{cd_1 ... d_k } = \hat t_{c d_k } ...
\hat t_{c d_1 } |\gamma_x \rangle_c |\tilde \gamma_1 \rangle_{d_1 }
... the values of transmittances @xmath151 of the beamsplitters @xmath152 ( eq . ( [ eqn35 ] ) ) and amplitudes @xmath164 of the reference modes @xmath145 ( eq . ( [ eqn75 ] ) ) are chosen in such a way , that amplitude of coherent state @xmath139 of the ancillary mode is split in equal parts between the modes @xmath145 , and each of the reference modes effectively undergoes coherent displacement @xmath484 : @xmath485 where @xmath486 is a linear function of the amplitude @xmath149 of the ancillary mode coherent state , equal to @xmath487 measuring presence of photons in the modes @xmath145 by the photodetectors can be described by a set of pairs of projective operators @xmath488 describing absence and presence of photons in corresponding field mode respectively . where the type of used projector ( `` + '' or `` - '' ) depends on the obtained measurement outcome .
this expression can be simplified using the following relation : @xmath490 where @xmath491 and @xmath492 are the sets of photon numbers , corresponding to the measurement outcomes `` - '' ( absence of photons detected ) and `` + '' ( photocount obtained ) respectively .
introducing superoperator , which describes measurement - invariant part of the ancillary mode state transformation by the definition @xmath493 one can transform eq .
( [ eqn31 ] ) for the density matrix @xmath203 to the form @xmath494 eq . ( [ eqn33 ] ) describes transformation of the system density matrix by elimination measurements in the form , similar to the one , corresponding to povm measurements .
it should be noted , however , that , the standard normalization condition is satisfied only for complete state transformation by the measuring setup ( including action of superoperator @xmath204 and @xmath61 operators @xmath497 , ... , @xmath498 ) rather than for single state elimination .
operators @xmath499 for @xmath500 correspond to the definition eq .
( [ eqn7 ] ) of operators , describing successful elimination of the state @xmath88 : @xmath501 ) , ( [ eqn23 ] ) , we can define operators @xmath502 , eliminating coherent state @xmath503 , as @xmath504 these operators satisfy the conditions , provided by eqs .
( [ eqn7 ] ) , ( [ eqn23 ] ) : @xmath505=0 \quad \mbox{for all } n_i,\,n_j.\ ] ] where eqs .
( [ eqn46 ] ) , ( [ eqn58 ] ) were taken into account . for small ancillary field amplitudes
@xmath13 the main contribution to the final state density matrix is made by the term with @xmath509 ( the most probable case of successful elimination of the states @xmath510 corresponds to detection of exactly 1 photon by each of the detectors ) . after discarding mode @xmath0 , the final state of modes @xmath2 and @xmath15 is described by density matrix | entanglement represents an important resource for quantum information processing , but its generation itself requires physical resources that are limited .
we propose a scheme for generating a wide class of entangled qudit - type states of optical field modes at sites separated by noisy medium when only weak optical nonlinearities are available at both sites .
the protocol is also based on exploiting a weak probe field , transmitted between the sites and used for generation of quantum correlations between two spatially separated field modes .
the idea of probabilistic entanglement enhancement by measurement is discussed , and corresponding scheme for measuring the probe field state with linear optics and photodetectors not resolving photon numbers is proposed .
it is shown that the protocol is applicable in the case when decoherence , limited efficiency and dark counts of photodetectors , and uncertainty of nonlinear coupling constants are present . |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Alaska Native and American Indian
Direct Reimbursement Act of 1998''.
SEC. 2. FINDINGS.
Congress finds the following:
(1) In 1988, Congress enacted section 405 of the Indian
Health Care Improvement Act (25 U.S.C. 1645) that established a
demonstration program to authorize 4 tribally operated Indian
Health Service hospitals or clinics to test methods for direct
billing and receipt of payment for health services provided to
patients eligible for reimbursement under the medicare or
medicaid programs under titles XVIII and XIX of the Social
Security Act (42 U.S.C. 1395 et seq.; 1396 et seq.), and other
third-party payors.
(2) The 4 participants selected by the Indian Health
Service for the demonstration program began the direct billing
and collection program in fiscal year 1989 and unanimously
expressed success and satisfaction with the program. Benefits
of the program include dramatically increased collections for
services provided under the medicare and medicaid programs, a
significant reduction in the turnaround time between billing
and receipt of payments for services provided to eligible
patients, and increased efficiency of participants being able
to track their own billings and collections.
(3) The success of the demonstration program confirms that
the direct involvement of tribes and tribal organizations in
the direct billing of, and collection of payments from, the
medicare and medicaid programs, and other third-party payor
reimbursements, is more beneficial to Indian tribes than the
current system of Indian Health Service-managed collections.
(4) Allowing tribes and tribal organizations to directly
manage their medicare and medicaid billings and collections,
rather than channeling all activities through the Indian Health
Service, will enable the Indian Health Service to reduce its
administrative costs.
(5) The demonstration program was originally to expire on
September 30, 1996, but was extended by Congress to September
30, 1998, so that the current participants would not experience
an interruption in the program while Congress awaited a
recommendation from the Secretary of Health and Human Services
on whether to make the program permanent.
(6) It would be beneficial to the Indian Health Service and
to Indian tribes, tribal organizations, and Alaska Native
organizations to provide permanent authorization for direct billing and
collection and to extend participation in direct billing and collection
to other Indian tribes, tribal organizations, and Alaska Native health
organizations who operate a facility of the Indian Health Service.
SEC. 3. DIRECT BILLING OF MEDICARE, MEDICAID, AND OTHER THIRD-PARTY
PAYORS.
(a) Permanent Authorization.--Section 405 of the Indian Health Care
Improvement Act (25 U.S.C. 1645) is amended to read as follows:
``SEC. 405. DIRECT BILLING OF MEDICARE, MEDICAID, AND OTHER THIRD PARTY
PAYORS.
``(a) Establishment of Direct Billing Program.--
``(1) In general.--Indian tribes, tribal organizations, and
Alaska Native health organizations that contract or compact for
the operation of any health program of the Service under the
Indian Self-Determination and Education Assistance Act may
elect to directly bill for, and receive payment for, health
care services provided by such health programs for which
payment is made under title XVIII of the Social Security Act
(42 U.S.C. 1395 et seq.) (in this section referred to as the
`medicare program'), under a State plan for medical assistance
approved under title XIX of the Social Security Act (42 U.S.C.
1396 et seq.) (in this section referred to as the `medicaid
program'), or from any other third-party payor.
``(2) Application of 100 percent fmap.--The third sentence
of section 1905(b) of the Social Security Act (42 U.S.C.
1396d(b)) shall apply for purposes of reimbursement under the
medicaid program for health care services directly billed under
the program established under this section.
``(b) Direct Reimbursement.--
``(1) Use of funds.--Each health program participating in
the program described in subsection (a) of this section shall
be reimbursed directly under the medicare and medicaid programs
for services furnished, without regard to the provisions of
section 1880(c) of the Social Security Act (42 U.S.C.
1395qq(c)) and sections 402(a) and 813(b)(2)(A), but all funds
so reimbursed shall first be used by the health program for the
purpose of making any improvements in the health facilities or
programs that may be necessary to achieve or maintain
compliance with the conditions and requirements applicable
generally to facilities or health programs of such type under
the medicare or medicaid programs. Any funds so reimbursed
which are in excess of the amount necessary to achieve or
maintain such conditions shall be used--
``(A) solely for improving the health resources
deficiency level of the Indian tribe; and
``(B) in accordance with the regulations of the
Service applicable to funds provided by the Service
under any contract or compact entered into under the
Indian Self-Determination Act (25 U.S.C. 450f et seq.).
``(2) Audits.--The amounts paid to the health programs
participating in the program established under this section
shall be subject to all auditing requirements applicable to
programs administered directly by the Service and to facilities
participating in the medicare and medicaid programs.
``(3) No payments from special funds.--Notwithstanding
section 1880(c) of the Social Security Act (42 U.S.C.
1395qq(c)) or section 402(a), no payment may be made out of the
special funds described in such sections for the benefit of any
health program during the period that the health program
participates in the program established under this section.
``(c) Requirements for Participation.--
``(1) Certification.--Except as provided in paragraph
(2)(B), in order to be eligible for participation in the
program established under this section, an Indian tribe, tribal
organization, or Alaska Native health organization shall submit a
certification to the Secretary that--
``(A) the Indian tribe, tribal organization, or
Alaska Native health organization contracts or compacts
for any part of the operation of a health program of
the Service; and
``(B) the health program is eligible to participate
in the medicare or medicaid programs under section 1880
or 1911 of the Social Security Act (42 U.S.C. 1395qq;
1396);
``(2) Grandfather of demonstration program participants.--
Any participant in the program authorized under this section as
in effect on the day before the date of enactment of the Alaska
Native and American Indian Direct Reimbursement Act of 1998
shall be deemed to have elected to participate in the program
established under this section and shall not be required to
submit a certification in order to participate in the program.
``(3) Duration.--A certification to the Secretary of a
qualified application under paragraph (1), or a deemed
certification of a demonstration program under paragraph (2),
shall continue in effect as long as the participant meets the
requirements of this section.
``(d) Examination and Implementation of Changes.--The Secretary,
acting through the Service and with the assistance of the Administrator
of the Health Care Financing Administration, shall examine on an
ongoing basis and implement any administrative changes that may be
necessary to facilitate direct billing and reimbursement under the
program established under this section, including any agreements with
States that may be necessary to provide for direct billing under the
medicaid program.
``(e) Withdrawal From Program.--A participant in the program
established under this section may withdraw from participation in the
same manner and under the same conditions that a tribe or tribal
organization may retrocede a contracted program to the Secretary under
authority of the Indian Self-Determination and Education Assistance Act
(25 U.S.C. 450 et seq.). All cost accounting and billing authority
under the program established under this section shall be returned to
the Secretary upon the Secretary's acceptance of the withdrawal of
participation in this program.''.
(b) Conforming Amendments.--
(1) Section 1990 of the Social Security Act (42 U.S.C.
1395qq) is amended by adding at the end the following:
``(e) Section 405 of the Indian Health Care Improvement Act (25
U.S.C. 1645) containing provisions relating to the authority of certain
Indian tribes, tribal organizations, and Alaska Native health
organizations to elect to directly bill for, and receive payment for,
health care services provided by a health program of such tribes or
organizations and for which payment may be made under this title shall
apply.''; and
(2) Section 1911 of the Social Security Act (42 U.S.C.
1396j) is amended by adding at the end the following:
``(d) Section 405 of the Indian Health Care Improvement Act (25
U.S.C. 1645) containing provisions relating to the authority of certain
Indian tribes, tribal organizations, and Alaska Native health
organizations to elect to directly bill for, and receive payment for,
health care services provided by a health program of such tribes or
organizations and for which payment may be made under this title shall
apply.''.
(c) Effective Date.--The amendments made by this section shall take
effect on October 1, 1998. | Alaska Native and American Indian Direct Reimbursement Act of 1998 - Amends the Indian Health Care Improvement Act to make permanent the authority (currently provided under a demonstration program) for Indian tribes, tribal organizations, and Alaska Native health organizations that contract or compact for the operation of any health program of the Indian Health Service to directly bill for, and receive payment for, health care services provided by such health programs for which payment is made under Medicare or Medicaid or from any other third party payor. Provides that: (1) such an entity shall be eligible to participate if it certifies that it contracts or compacts for any part of the operations of a Service health program that is eligible to participate in the Medicare or Medicaid programs; and (2) entities participating in a demonstration program as in effect the day before enactment of this Act shall be deemed to have elected to participate and shall not be required to make such certification. Provides for: (1) the ongoing examination and implementation of necessary administrative changes to facilitate direct billing and reimbursement under the program; and (2) withdrawal from participation in the program. |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Strengthen Social Work Training Act
of 2005''.
SEC. 2. SOCIAL WORK STUDENTS.
(a) Health Professions Schools.--Section 736(g)(1)(A) of the Public
Health Service Act (42 U.S.C. 293(g)(1)(A)) is amended by striking
``graduate program in behavioral or mental health'' and inserting
``graduate program in behavioral or mental health, including a school
offering graduate programs in clinical social work, or programs in
social work''.
(b) Scholarships.--Section 737(d)(1)(A) of the Public Health
Service Act (42 U.S.C. 293a(d)(1)(A)) is amended by striking ``mental
health practice'' and inserting ``mental health practice (including
graduate programs in clinical psychology, graduate programs in clinical
social work, or programs in social work)''.
(c) Faculty Positions.--Section 738(a)(3) of the Public Health
Service Act (42 U.S.C. 293b(a)(3)) is amended by striking ``offering
graduate programs in behavioral and mental health'' and inserting
``offering graduate programs in behavioral and mental health, including
graduate programs in clinical psychology, graduate programs in clinical
social work, or programs in social work''.
SEC. 3. GERIATRICS TRAINING PROJECTS.
Section 753(b)(1) of the Public Health Service Act (42 U.S.C.
294c(b)(1)) is amended by inserting ``schools offering degrees in
social work,'' after ``teaching hospitals,''.
SEC. 4. SOCIAL WORK TRAINING PROGRAM.
Subpart 2 of part E of title VII of the Public Health Service Act
(42 U.S.C. 295 et seq.) is amended--
(1) by redesignating section 770 as section 770A;
(2) by inserting after section 769, the following:
``SEC. 770. SOCIAL WORK TRAINING PROGRAM.
``(a) Training Generally.--The Secretary may make grants to, or
enter into contracts with, any public or nonprofit private hospital,
any school offering programs in social work, or to or with a public or
private nonprofit entity that the Secretary has determined is capable
of carrying out such grant or contract--
``(1) to plan, develop, and operate, or participate in, an
approved social work training program (including an approved
residency or internship program) for students, interns,
residents, or practicing physicians;
``(2) to provide financial assistance (in the form of
traineeships and fellowships) to students, interns, residents,
practicing physicians, or other individuals, who--
``(A) are in need of such assistance;
``(B) are participants in any such program; and
``(C) plan to specialize or work in the practice of
social work;
``(3) to plan, develop, and operate a program for the
training of individuals who plan to teach in social work
training programs; and
``(4) to provide financial assistance (in the form of
traineeships and fellowships) to individuals who are
participants in any such program and who plan to teach in a
social work training program.
``(b) Academic Administrative Units.--
``(1) In general.--The Secretary may make grants to or
enter into contracts with schools offering programs in social
work to meet the costs of projects to establish, maintain, or
improve academic administrative units (which may be
departments, divisions, or other units) to provide clinical
instruction in social work.
``(2) Preference in making awards.--In making awards of
grants and contracts under paragraph (1), the Secretary shall
give preference to any qualified applicant for such an award
that agrees to expend the award for the purpose of--
``(A) establishing an academic administrative unit
for programs in social work; or
``(B) substantially expanding the programs of such
a unit.
``(c) Duration of Award.--The period during which payments are made
to an entity from an award of a grant or contract under subsection (a)
may not exceed 5 years. The provision of such payments shall be subject
to annual approval by the Secretary and subject to the availability of
appropriations for the fiscal year involved to make the payments.
``(d) Funding.--
``(1) Authorization of appropriations.--There are
authorized to be appropriated to carry out this section
$10,000,000 for each of the fiscal years 2006 through 2008.
``(2) Allocation.--Of the amounts appropriated under
paragraph (1) for a fiscal year, the Secretary shall make
available not less than 20 percent for awards of grants and
contracts under subsection (b).''; and
(3) in section 770A (as redesignated by paragraph (1)) by
inserting ``other than section 770,'' after ``carrying out this
subpart,''.
SEC. 5. CLINICAL SOCIAL WORKER SERVICES.
Section 1302 of the Public Health Service Act (42 U.S.C. 300e-1) is
amended--
(1) in paragraphs (1) and (2), by inserting ``clinical
social worker,'' after ``psychologist,'' each place the term
appears;
(2) in paragraph (4)(A), by striking ``and psychologists''
and inserting ``psychologists, and clinical social workers'';
and
(3) in paragraph (5), by inserting ``clinical social
work,'' after ``psychology,''. | Strengthen Social Work Training Act of 2005 - Amends the Public Health Service Act to include clinical psychology and social work programs among eligible health education programs for purposes of receiving grants to: (1) support programs for underrepresented minorities; (2) provide scholarships to disadvantaged students; and (3) offer faculty positions to disadvantaged students.
Allows the Secretary of Health and Human Services to make grants to, and enter into contracts with: (1) schools offering degrees in social work to provide support for geriatric training projects; (2) hospitals, schools, or other entities to plan or operate an approved social work training program and to provide financial assistance to program participants that are planning to specialize, work, or teach in the field of social work; and (3) schools offering social work programs to establish, maintain, or improve academic administrative units to provide clinical instruction in social work.
Authorizes health maintenance organizations (HMOs) to offer health services through a clinical social worker as provided for under State law. |
quantum entanglement has many applications including quantum teleportation @xcite , quantum cryptography @xcite , and quantum communication @xcite .
this has led people to regard entanglement as a resource .
however , entanglement can exist in different forms and so it is useful to know how it can be manipulated from one form to another . in this paper
the problem of manipulating a general pure two - particle entangled state in order to obtain maximally entangled states will be considered .
we will also consider the problem of how to manipulate one general pure two - particle entangled state to another .
alice and bob are allowed to do whatever they want locally and they are allowed to communicate classically with one another .
they are not allowed to exchange quantum states .
this type of situation has already been much discussed in the literature .
the problem of how to optimally manipulate a large number , @xmath4 , of copies of a general pure two - particle entangled states into maximally entangled states by local means has been completely solved in the asymptotic limit @xmath5 @xcite .
however , the perhaps more basic problem of how to manipulate a single copy of a general pure two - particle state into maximally entangled states has not been so extensively discussed .
the most significant work on this is by lo and popescu @xcite who prove certain bounds relating to this problem .
however their proofs , while being extraordinarily ingenious , are rather difficult to follow .
the method developed in this paper , which completely solves the problem , involves the cutting and pasting of areas along with a colouring problem .
once the basic methods have been put in place , it is very easy to picture what is happening .
this method is used to find the maximum obtainable average entanglement and to derive a formula of lo and popescu which gives the maximum probability of obtaining a given maximally entangled state .
a related problem is how to transform one pure two - particle entangled state to another , and to establish which states will transform to one another in this way .
nielsen @xcite has completely solved this problem .
however his proof of his theorem uses some unfamiliar mathematics .
an alternative reasonably simple proof of nielsen s theorem is given here which , again , involves cutting and pasting of areas along with a certain colouring problem .
the most general pure two - particle state can be written in the schmidt form @xmath6 and where the states @xmath7 are orthonormal .
we want to manipulate this state in order to obtain states which are of the form @xmath8-state .
an @xmath9-state is equivalent to @xmath10 copies of 2-states @xcite . after the process
is completed we should have a certain @xmath9-state with a certain probability @xmath1 .
particle a goes to alice and particle b goes to bob .
alice and bob are allowed to perform whatever operations they want locally and also they communicate classically with each other .
this can happen in the following way .
alice performs a measurement and communicates the result to bob who then performs a measurement which depends on the result of alice s measurement , and then bob communicates his result back to alice and she makes another measurement , and so on back and forth .
this is most general way in which alice and bob can manipulate their state without actually exchanging quantum states in the process .
whatever measure of entanglement we employ , the amount of entanglement should not increase during such a process .
lo and popescu show that , for the very special case of a two - particle pure state , this process is equivalent to one in which alice makes one measurement and communicates the result to bob who then may perform a unitary evolution operation on his particles .
the reason for this significant simplification is that , due to the schmidt decomposition , any operation by bob is equivalent , so far as the resulting form of the state is concerned , to some operation by alice .
hence , alice can simply do everything herself in one go and then communicate the final result to bob .
the most general measurement alice can make is a povm .
this is equivalent to alice introducing an ancilla , @xmath11 , performing a general unitary evolution on particle @xmath12 and the ancilla @xmath11 , and then making a projective measurement on the ancilla .
let us imagine that the ancilla has a basis set of states @xmath13 . since we allow completely general evolution of @xmath14 we can assume , without loss of generality , that the final measurement projects onto subspaces spanned by the states @xmath13 .
furthermore , it is shown in the appendix that there is no advantage to be had by performing a non - maximal ( i.e. degenerate ) measurement and so we can assume that this measurement is maximal and projects onto the operators @xmath15 .
for each outcome , @xmath16 , the two particles @xmath12 and @xmath17 should be projected into an @xmath9-state @xmath18 where @xmath19 for @xmath20 .
after alice has communicated the result , @xmath16 , of the measurement to bob , bob could rotate these vectors into the same standard form for all @xmath16 ( thus removing the need for the superscript at this stage ) , but this is not important .
it is enough that alice and bob know what @xmath16 is so they know what state they have .
we do not require a superscript @xmath16 on the @xmath21 states since , as explained below , alice can rotate her schmidt vectors to standard form as part of the overall unitary transformation she performs . just before alice makes her measurement projecting onto @xmath13 the state of the system will be @xmath22 can be taken to be real since any phases can be absorbed into appropriately redefined @xmath13 . note that if , at this stage , the @xmath23 states had a superscript @xmath16 then they could be rotated into standard form by applying a series of controlled unitary operations , @xmath24 , to @xmath12 where the control is the @xmath13 state . at this stage alice
has not done anything which is irreversible . having completed her local manipulations alice will perform a maximal projective measurement .
it follows from the result of lo and popescu that manipulating the state into the form ( [ targeta ] ) and then measuring onto the @xmath13 basis is equivalent to the most general procedure for manipulating the two particles by local means to @xmath9-states .
we will use equation ( [ targeta ] ) later when we come to show that the method developed in the next section is equivalent to the most general method . now consider the initial state @xmath2 given in equation ( [ psi ] ) .
we will introduce an ancilla , @xmath25 , in the state @xmath26 .
this ancilla has basis states @xmath27 where @xmath28 .
we will take @xmath4 to be very large and will want to consider the case where @xmath4 tends to infinity .
we define the integers @xmath29 where , for the moment , we are taking the @xmath30 to be rational numbers so the integers @xmath31 can be found with @xmath4 finite .
this constraint can be relaxed when @xmath4 tends to infinity .
the initial state of @xmath32 is @xmath33 .
alice now evolves @xmath34 using the following transformations . @xmath35 the fact that these transformations evolve orthogonal states to orthogonal states ensures that they can be implemented by unitary evolution . under these transformations
the state @xmath33 evolves to latexmath:[\[\label{eqamp } state_. we see that each of the @xmath4 terms in this superposition has the same amplitude .
each of these terms will be represented by a rectangular element width 1 and height @xmath37 .
the area of the element is @xmath37 and equal to the probability associated with the corresponding term in ( [ eqamp ] ) .
each element can be labelled by @xmath38 corresponding to the term @xmath39 ( initially @xmath40 but after alice has performed operations on her particles this will not necessarily be the case for every term ) .
the elements are then arranged on a graph where elements having the same @xmath41 are placed in the same row and elements having the same @xmath42 are placed in the same column .
the resulting graph looks like a series of steps as shown in fig .
[ fig1 ] . we will call this the _ area diagram_. the total area under the steps is 1 corresponding to the total probability . on the vertical axis @xmath43 is plotted . on the horizontal axis the @xmath42 which appears in @xmath23 is plotted . for small @xmath41 every @xmath42 position will be filled .
however , because of the form of the state ( [ eqamp ] ) , once @xmath41 gets bigger than @xmath44 there will no longer be any @xmath45 terms .
this is the reason for the step at @xmath46 .
there will be further steps at each @xmath47 .
the height of the rightmost step is @xmath48 .
subsequent steps will be at heights @xmath30 as shown in fig .
[ fig1 ] . if a projective measurement were to be performed on @xmath25 at this stage then , corresponding to each outcome @xmath41 , the state of @xmath49 would be projected onto an @xmath9-state where @xmath9 is equal to the number of elements in the @xmath41th row on the area diagram .
this will give a distribution of @xmath9-states with probabilities which are equal to the large horizontal rectangular areas of width @xmath9 and height @xmath50 formed by extending the horizontal parts of the step back to the vertical axis .
however , the area in the diagram can be moved around by alice in a way to be described below by performing local unitary operations . when this is followed by a projective measurement on @xmath25 different distributions of @xmath9-states
can be realised .
the terms @xmath39 and @xmath51 are bi - orthogonal iff @xmath52 ( orthogonal at alice s end ) and @xmath53 ( orthogonal at bob s end ) .
if two terms are only orthogonal at either alice s end or at bob s end then they are mono - orthogonal . in the area diagram
we will impose the constraint that all elements in a row , that is for a given @xmath41 , correspond to terms which are bi - orthogonal .
this ensures that when we perform a projective measurement onto @xmath25 the resulting state will be an @xmath9-state .
we will colour all the elements which correspond to terms which are mono - orthogonal to one another a given colour .
elements corresponding to terms which are bi - orthogonal will be coloured with different colours .
thus , initially , all the elements in a given column are the same colour and every column is coloured a different colour to every other column . when area is moved around the constraint that terms corresponding to elements in a row be bi - orthogonal means that all elements in any given row must be different colours .
the method of areas to be developed here involves moving area elements around in such a way that there is a net movement of area up and to the left .
we will see that it is possible to have a net movement of area up the area diagram but not down the diagram .
this means that the net movement of area across any horizontal line drawn on the diagram must be up .
the basic unitary operation , @xmath54 , employed by alice is defined by the transformation equations @xmath55 @xmath56 with no change for all other @xmath57 .
we will call this the swap operation .
the effect of this operation is to move elements around on the area diagram .
if there are elements at both the @xmath38 and @xmath58 positions then they will have their positions swapped .
if , there is only an element at one of the two positions then it will be moved to the other position while the original position will become vacant .
these moves will not effect bob s part of the state .
if two terms are bi-(mono)-orthogonal before the swap operation is applied to one or both of them then they will be bi-(mono)-orthogonal afterwards . in other words ,
the swap operation does not change the colour of the elements .
initially , as stated above , all elements in the same row are different colours and elements in the same column are the same colour .
in moving elements of area around we impose only the constraint that , at the end of the process , all elements in a row are different colours .
although elements in any given column start off being the same colour , we do not demand that this is true at the end of the process .
we can move a large number of elements at once . in the limit as @xmath59
the elements will become infinitesimal in height .
hence , in this limit , we can make horizontal cuts anywhere .
we can make vertical cuts along the edges of the columns .
the area can be cut up into smaller pieces and then pieces can be moved around and pasted into new positions .
it is possible to move area around like this in any way we want by repeated applications of the swap operation .
the empty space above the steps can be used as a clipboard for the temporary storage of pieces of area to facilitate the rearrangement of area if required . in fig .
[ fig2 ] the original step structure is shown by a full line .
a new step structure is shown by a dashed line .
we will impose the constraint ( to be justified later ) that the new step structure consists of steps which , like the original steps , go across and down ( but never up ) towards the right .
the area @xmath60 which will be cut away from some parts of the steps is equal to the area @xmath61 which will be added to other parts of the steps .
each of these areas consist of @xmath25 smaller disjoint parts labelled by @xmath62 going up the diagram .
note , area @xmath63 lies between area @xmath64 an @xmath65 .
note also that the areas @xmath64 and @xmath63 can themselves be made up of disjoint parts .
the constraint that there is no net movement of area downwards means that @xmath66 for all @xmath67 .
the original steps are of height @xmath30 .
let the new steps be of height @xmath68 .
since the columns are of unit width , these lengths are numerically equal to the areas of the columns , and hence the constraint that area is moved only to the left is equivalent to the set of constraints @xmath69 for all @xmath70 to @xmath71 with equality holding when @xmath70 .
we could simply move the area @xmath11 to the area @xmath72 element by element by applying the swap operator .
however , if we did this it is likely that elements corresponding to mono - orthogonal terms would end up in the same row . if we can redistribute the area so that it corresponds to the new step structure but without there being any elements of the same colour in the same row then we will have realised another distribution of @xmath9-states
this is because alice could then perform a projective measurement on @xmath25 and corresponding to each outcome , @xmath41 , will be a @xmath9-state and these @xmath9-states will clearly have a different distribution .
the probability of a given @xmath9 state is equal to the area of the horizontal rectangle formed by projecting leftwards the top and bottom of the step at position @xmath9 .
this rectangle has width @xmath9 and height @xmath73 .
hence , for the new area diagram , the probability of getting an @xmath9 state is @xmath74 we will show firstly that this colouring problem can be solved and secondly that the process described here is general in the sense that any distribution of @xmath9-states which can be achieved by local means can be achieved by this method .
hence , equations ( [ newsteps ] ) and ( [ psubm ] ) define the possible distributions of @xmath9-states that can be obtained .
the solution to the colouring problem will be explained by reference to the example shown in fig .
[ fig3 ] .
this example has @xmath75 ( since all of @xmath72 is above all of @xmath11 ) .
however , it will be clear that the method works for the general case .
we start by taking the rightmost column in the area @xmath11 .
this is area @xmath12 in fig [ fig4](a ) .
this area is then swapped into the rightmost column of the area @xmath72
so that point @xmath76 coincides with point @xmath77 as shown in fig . [
fig4](b ) .
however , it may be too long to all fit in to the right most column of area @xmath72 ( as is indeed the case in our example ) , and hence it will displace some of the area in the column below this , marked as area @xmath17 in fig .
[ fig4](a ) .
because of the nature of the swapping operation , this area @xmath17 will be moved to the old position of @xmath12 so that point @xmath78 coincides with point @xmath79 as shown in fig . [ fig4](b ) .
area @xmath12 is now in its final position .
let us imagine that the column from which area @xmath12 was taken was coloured red .
this red colour will now be divided between what is left of the original column and the area @xmath12 in its new position . since the steps go up towards the left , it is impossible to have red at more than one position in any given row .
the rightmost column of @xmath72 is now filled so we start on the next rightmost column .
we swap area @xmath17 into position in the next rightmost column of area @xmath72 . again
, this could be too long . in our example
it is too long and projects into the column below into the area marked @xmath80 .
hence @xmath80 will be moved to where @xmath17 was .
this takes us to the situation shown in fig .
[ fig4](c ) .
now we move area @xmath80 into position in the next rightmost column of area @xmath72
. this could again be too long and project into the column below , but in this example this is not the case .
rather , area @xmath80 is too short leaving a gap .
hence no area is moved back to the rightmost column of @xmath11 and this means we have finally dispensed with the net effect of moving the area from this rightmost column of @xmath11 .
now we select the next rightmost column of @xmath11 . in our example
this area is marked @xmath81 in fig .
[ fig4](c ) .
this area is now moved up following the same procedure .
thus , we move @xmath81 into position as high as possible in the rightmost column of @xmath72 which has not yet been filled .
this places it below area @xmath80
. it could be the case that @xmath80 is too long and projects into the column below in which case some area would be swapped back and we would have to continue as before .
however , in our particular example area @xmath81 fits in below @xmath80 and the recolouring is finally completed as shown in fig . [ fig4](d ) .
this method can be applied to any recolouring problem of this nature .
the general method is that area is swapped from the rightmost non - empty column of @xmath11 to as high a position as possible in the rightmost non - full column of @xmath72 .
we note that a given colour can end up in , at most , two different columns and that any colour moved from a column will always end up higher than its original position .
this means that it is impossible for two elements of area which started in the same column ( having the same colour ) to end up in the same row .
hence , the colouring problem has been solved .
having shown that it is possible to have a net movement of area up the area diagram in any general way which is consistent with maintaining the step structure , we will now show that this corresponds to the most general way of manipulating entanglement to produce @xmath9-states in the sense that any distribution of @xmath9-states which can be achieved by local operations classical communication can be achieved by this method .
the idea of this proof will be to show that the target state ( just before alice measures on to the ancilla ) can be put into a certain form which is inconsistent with any movement of area downwards .
we have already established that the most general final state just before alice makes her measurement ( we call this the _ target state _ ) is the state given in ( [ targeta ] ) .
if we write @xmath82 then ( [ targeta ] ) becomes @xmath83 we can consider further unitary transformations by alice on this state to put it into a form in which every term has the same amplitude . let the dimension of the ancilla @xmath11 be @xmath84 and define @xmath85 ( again we will let @xmath86 ) and let alice perform the following transformations on ( [ targeta ] ) : @xmath87 where @xmath88 is the set of @xmath89 integers from @xmath90 to @xmath91 ( we put @xmath92 ) . under this transformation ( [ targeta ] ) becomes @xmath93 every term in this state has the same amplitude . in arriving at this state from the previous target state ( [ targeta],[targetap ] )
we have done nothing that is irreversible .
furthermore , if we measure onto the @xmath94 basis we are just as likely to get a given @xmath9-state as with the previous target state .
hence , we can regard this as our new target state .
any method by which @xmath9-states can be obtained is equivalent to manipulating the state into the form ( [ targetb ] ) .
if we project onto @xmath94 we will obtain an @xmath95-state where @xmath95 can be read off from ( [ targetb ] ) .
we can relabel the @xmath41 s such that @xmath96 .
thus , we can impose the following : constraint a : : if outcome @xmath41 corresponds to a @xmath95-state then , without loss of generality , we can impose the constraint that @xmath96 . by examining ( [ targetb ] )
we can see that there is a second constraint that can be imposed on the form of the final target state .
constraint b : : for the target state we can , without any loss of generality , impose the constraint that @xmath97 where @xmath98 is any normalised state for system @xmath17 since this is true of equation ( [ targetb ] ) .
we can identify the ancilla @xmath11 with the ancilla @xmath25 introduced earlier .
hence , @xmath99 and @xmath100 .
now consider the state ( [ psi ] ) .
since alice s operations do not effect bob s system we see that we have the following constraint : constraint c : : while the state @xmath101 is being manipulated by local unitary operations by alice , we will always have @xmath102 for all @xmath103 .
since ( [ eqamp ] ) is related to ( [ psi ] ) by reversible operations , we can take ( [ eqamp ] ) , which corresponds to an area diagram , as our starting point .
we will now see that area can not be moved down in the area diagram . for the purposes of this proof consider a change in the way the area diagram is plotted such that the @xmath103 in @xmath104 ( rather than the @xmath42 in @xmath23 ) is plotted on the horizontal axis .
this will simply have the effect of redistributing elements horizontally but not vertically since @xmath43 is still plotted on the vertical axis .
we label elements in this modified area diagram by @xmath105 .
constraint c implies that the column corresponding to a given @xmath103 on this modified area diagram will always have the same area .
this is because alice s actions can not effect the total area ( or probability ) associated with column @xmath103 .
however , alice can change the @xmath41 value associated with area elements and hence she can move area in column @xmath103 up and down .
it is possible that she can bring about a net movement of area ( or probability ) down in this column .
this would lead to the area being compressed into a smaller space than it would naturally fit .
any net movement of area downwards , whether on the @xmath105 picture or the @xmath38 picture would correspond to this happening in at least one @xmath103 column .
this is exactly what we want to rule out .
we will now see that any such net movement downwards will violate constraint @xmath17 ( which we were free to impose on the target state ) .
if , at some stage , the state has been manipulated to the state @xmath101 then the area of the @xmath105 element will be @xmath106 .
initially , for the start state @xmath107 in ( [ eqamp ] ) , we have @xmath108 for all @xmath109 . however , if there is a net movement of area down the area diagram with respect to the horizontal line @xmath110 then , since the total area in a given column is constant ( by constraint c ) , this net movement of area downwards must happen in at least one column of the modified area diagram .
hence , for at least one value of @xmath103 , we must have @xmath111 however , since @xmath100 , equation ( [ conb ] ) implies @xmath112 the contradiction between ( [ areabig ] ) and ( [ areasmall ] ) proves that a net movement of area downwards is not possible on the modified area diagram and hence neither is it possible on the unmodified area diagram .
note that this proof goes through for any sort of operations by alice and in particular it does not assume that the only operations alice can make are the swap operations defined in ( [ swap ] ) . to complete the proof that the manipulations described earlier are equivalent to the most general way of manipulating the state to obtain @xmath9-states we note the following .
\(i ) the target state ( [ targetb ] ) can be represented on an area diagram in which @xmath43 ( where @xmath113 ) is on the vertical axis and @xmath95 is plotted on the horizontal axis .
since @xmath95 is an integer and since we can impose constraint a without loss of generality , this area diagram will have a step structure ( in which the steps of integer width go down towards the right ) .
\(ii ) the initial state can be taken to be the start state @xmath107 given in ( [ eqamp ] ) and this can be represented by an area diagram with the step structure .
\(iii ) the total area of both these diagrams is 1 .
therefore the most general way of manipulating the start state into @xmath9-states corresponds to going from one area diagram with the step structure to another with the step structure in a way consistent with the constraint that there is no net movement of area downwards .
\(iv ) the method , employing the swap operator , discussed previously can be used to go from one step structure to another in any way that is consistent with there being no net downward movement of area .
hence , it is equivalent to the most general method .
if we are only interested in the average amount of entanglement in the form of maximally entangled states we can obtain , this being equal to @xmath114 , then it turns out that any movement of area will decrease this average .
hence this average has a maximum given by the original area diagram @xmath115 to see that any movement of area will decrease this average , consider moving one element on the area diagram ( with area equal to @xmath116 ) from the end of row @xmath12 which has original width @xmath117 , to the end of row @xmath17 which has original width @xmath118 .
since we can only move area to the left we require that @xmath119 ( if @xmath120 then the rows will simply have interchanged their lengths and hence there will be no change in the distribution of @xmath9-states ) .
the original contribution of these two rows to @xmath121 will be @xmath122 the contribution afterwards will be @xmath123 the difference between these two contributions is @xmath124\ ] ] it can only be advantageous to move elements of area if this quantity is positive .
however , by making the substitutions @xmath125 we can see that @xmath126 is negative if @xmath127 .
the constraint that @xmath128 implies that @xmath129 and hence any movement of area must lead to a smaller @xmath121 .
we also see from this that since only one distribution of @xmath9-states leads to the maximum @xmath121 , any attempt to alter the distribution of @xmath9-states will result in a decrease of @xmath121 ( and so we obtain another main result of lo and popescu ) .
we will now use this method to derive a formula central to the paper of lo and popescu @xcite .
imagine that we have a general two - particle pure entangled state and we want to have a given @xmath9-state with as high a probability as possible .
we want to know what this probability is and what strategy to use .
this corresponds to the area redistribution shown in fig .
[ fig5 ] .
the target area diagram consists of a block of width @xmath9 with an additional bit on top .
this defines @xmath130 and @xmath131 ( see diagram ) .
the area @xmath11 has been moved to the area @xmath72 where these two areas are equal .
the height of the main block is @xmath131 which can be calculated since we know that @xmath132 where the last equality follows from the fact that the @xmath42th column is of area @xmath30 .
the total probability of getting the @xmath9-state is equal to the area of the main block , i.e. @xmath133 .
we can use this formula if we know what @xmath130 is since then @xmath131 can be calculated from ( [ rzero ] ) .
this can be established by the following considerations .
define the area @xmath134 to consist of all the columns @xmath135 to @xmath9 in the start area diagram so that @xmath136 where @xmath137 .
the area @xmath138 consists of a main block of width @xmath62 and height @xmath131 plus , for @xmath139 , an extra bit lying outside this block ( when @xmath140 a bit of @xmath72 lies outside this block and when @xmath141 a bit of @xmath134 lies outside the block ) .
hence , @xmath142 with equality in the case @xmath143 .
therefore , @xmath144\ ] ] and we obtain the formula of lo and popescu @xmath145 where @xmath146 . the geometric origin of this formula is now clear .
the set of constraints ( [ newsteps ] ) are exactly nielsen s condition @xcite for being able to manipulate an entangled state , @xmath2 , with schmidt coefficients @xmath147 to another , @xmath3 , with schmidt coefficients @xmath148 .
however , we can not immediately interpret the new area diagram as being equivalent to a @xmath3 state since , unlike in the original area diagram , a given column can be multicoloured .
we will see that , nevertheless , we can use the area diagrams to prove nielsen s theorem .
this proof works along similar lines to the previous proof .
first , we put the target state into step form .
alice introduces an ancilla @xmath11 of dimension @xmath84 with basis states @xmath13 .
if the problem can be solved then , for similar reasons to before , she must be able to manipulate the total state into the form @xmath149 ) into ( [ prime ] ) we obtain @xmath150 .
we apply the transformation @xmath151 where @xmath152 is the set of integers from @xmath153 to @xmath154 ( we set @xmath155 ) . under this transformation ( [ ntarget ] ) becomes @xmath156 each term has equal amplitude in this state .
if we project it onto @xmath94 then we will get a state with , say , @xmath95 terms ( where @xmath95 can be read off from ( [ nbtarget ] ) ) not all of which are bi - orthogonal .
we can relabel the @xmath41 s so that @xmath157 and hence we can draw an area diagram with a step structure .
the terms corresponding to a given @xmath41 are not necessarily bi - orthogonal and hence we can not impose on the target area diagram the constraint that elements in a row must all be coloured different colours .
rather we will have a different colouring problem .
as before , we will identify the systems @xmath11 and @xmath25 so that @xmath100
. the start state is @xmath107 in ( [ eqamp ] ) and is represented by an area diagram with step structure in which each column is coloured with only one colour , this being different to the colour of the other columns .
the target area diagram is shown in fig .
since this has been recoloured the columns in this diagram will not necessarily be of one colour .
the height of the @xmath42th column is @xmath158 .
we chose a number @xmath159 which we will let tend to infinity , though in the fig .
[ fig6 ] we have set @xmath160 .
we divide each column up equally into @xmath159 pieces which are numbered @xmath161 starting at the bottom .
the @xmath162th piece in the @xmath42th column is labelled @xmath163 $ ] if the target area diagram has been obtained from the start area diagram by moving finite sized bits of area around ( as will be the case in our recolouring strategy ) then there will be a finite number of horizontal boundaries between different colours .
some of the pieces @xmath163 $ ] are likely to have these boundaries on them . however , as @xmath164 the total area of such pieces will tend to zero and we can assume that each piece has a unique colour . the idea will be to collect all the pieces with a given @xmath162 .
since their areas are proportional to @xmath68 they can correspond to the new state @xmath165 .
each of these pieces having the same @xmath162 must be coloured with a different colour since the terms in @xmath165 are bi - orthogonal .
there are @xmath166 terms in the state vector corresponding to each column , and since these are divided into @xmath159 pieces , there are @xmath167 terms corresponding to the @xmath163 $ ] piece which will be of the form ( unnormalised ) @xmath168\rangle = { 1\over\sqrt{n } } \sum_{n=(q-1)n'_i / q+1}^{qn'_i / q } all such terms
. we can transform the total state by applying the transformation @xmath169 for all @xmath170 .
this sends the term @xmath171\rangle$ ] to the state @xmath168'\rangle = \sqrt{\lambda'_i \over q } simplified the state of the ancilla @xmath25 for the terms corresponding to each piece @xmath163 $ ] . in so doing
we have recovered the coefficient @xmath172 .
the total state is now @xmath173 now , if we measure onto the @xmath174 basis we get a state which is a realisation of @xmath3 iff the terms are bi - orthogonal . in colouring terms
, this means we require that all the pieces labelled with the same @xmath162 in fig .
[ fig6 ] should be of different colour .
thus , we have another colouring problem . if we can solve this colouring problem under the assumption that net movement of area is up , then we will have given a constructive proof that nielsen s bound can be obtained . to complete the proof of nielsen s theorem
we need to show that area can only be moved up .
this will be done later . a way to solve this colouring problem
was suggested to the author by a. mahtani .
this solution is obtained simply by correcting the solution to the previous colouring problem in sec .
2.2 @xcite firstly , this colouring procedure , illustrated by example in fig . [ fig4 ] , is used to go from the start area diagram ( representing @xmath2 ) to the target diagram where the heights of the columns are @xmath68 .
now we note that it is a property of this recolouring procedure that a given colour can end up in two columns at most .
there are two ways in which a piece of area can be moved to the left .
either it can be moved directly ( as are the pieces @xmath12 and @xmath81 in fig .
[ fig4 ] , or it can first be swapped to the right and then be moved back to a further left position than it started in ( as are pieces @xmath17 and @xmath80 in fig .
[ fig4 ] ) .
we will call the first type _ directly swapped _ pieces and the second type of pieces the _ swapped back _ pieces . since these swapped back pieces ( for example , piece @xmath17 )
must be shorter than the piece that displaced them from their original column ( in the case of @xmath17 this was piece @xmath12 ) , since they always end up at the top of their destination column , and since the column they end up in is higher than their starting column , they must occupy proportionally less of their final column than the pieces that displaced them ( piece @xmath17 occupies proportionally less of its final column than piece @xmath12 of its final column ) .
this means that when the columns are divided up into a large number , @xmath159 , of equal pieces the colours of the swapped back pieces will not appear in two pieces with the same @xmath162 .
hence , we will first correct the other colours .
however , the procedure which corrects the colours of the directly swapped pieces disturbs this property of the swapped back pieces . hence , after correcting for a bunch of directly swapped pieces , we will have to correct for the swapped back pieces as well .
first we will consider the colours corresponding to the directly swapped pieces . before we do that
note that some columns will remain unchanged ( neither have area moved into them , or out of them ) and hence their colour can not end up in two pieces with the same @xmath162 .
these columns can be completely ignored and we can consider only the remaining columns .
we start at the rightmost column and go left considering only the columns which have changed .
the first changed columns we meet will be shorter than originally , will each be coloured with only one colour , and will have had some area swapped out of them directly .
after one or more of these monochromatic columns , we will meet a column into which these directly swapped pieces have been moved .
the last directly swapped piece may displace a piece from this column which will be a swapped back piece @xmath11 .
this piece , when it is swapped back , will end up at a column , @xmath175 , somewhere to the left .
but before we get there , we may meet a few more monochromatic columns , @xmath176 , from which pieces @xmath177 have been directly swapped .
we will count @xmath178 backwards so first we meet @xmath179 as we go leftwards .
eventually , on our journey leftwards , we meet column @xmath175 into which @xmath11 has been swapped , then pieces @xmath180 to @xmath181 . when the last piece @xmath181 is swapped into position it may displace piece @xmath182 which will be swapped back .
thus , we will repeat the same story as we continue leftwards .
columns will come in bunches of a few monochromatic columns ( such as @xmath176 ) followed by a multicoloured column ( like @xmath175 ) .
the columns @xmath175 and @xmath176 are shown in fig . [ fig7](a ) for the case @xmath183 .
columns not relevant to the present discussion are not shown .
we label the original colour of @xmath175 as @xmath184 and the colour of @xmath176 as @xmath185 .
various distances ( which are numerically equal to areas since the columns are of unit width ) are marked on the figure .
the strategy we will adopt is the following .
we note that , as things stand , the colour @xmath185 in all of @xmath176 also appears in @xmath175 and hence , there must be some of the same colour in different columns for the same @xmath162 . to correct this , we can swap an area , @xmath186 , of colour @xmath184 from @xmath175 into @xmath176 thus swapping the same area , @xmath186 , of @xmath185 back into @xmath175 .
we do this for all @xmath187 .
we then re - sort column @xmath175 so that @xmath186 lies immediately below @xmath177 , both these areas being of the same colour @xmath185 and so that colour @xmath188 is above colour @xmath189 , etc .
this is shown in fig .
[ fig7](b ) ( the role of area @xmath190 will be explained later ) .
we choose @xmath191 to be such that the proportion of @xmath185 in @xmath175 relative to the height of @xmath175 is equal to the proportion of @xmath184 in @xmath176 relative to the height of @xmath176 .
this condition can be expressed as @xmath192 furthermore , the area @xmath186 of colour @xmath184 is placed in @xmath176 at the same relative position of @xmath176 as the area @xmath193 of colour @xmath185 has been placed in column @xmath175 ( see fig . [
fig7](b ) ) .
this ensures that when the columns are divided up as shown in fig .
[ fig6 ] , but with @xmath159 large , the pieces @xmath194 $ ] in @xmath175 of colour @xmath185 will have a different colour from the pieces @xmath195 $ ] in @xmath176 since the latter pieces will be of colour @xmath184 .
having carried out this correcting procedure for these columns we see that there is a problem .
piece @xmath182 which has been swapped back somewhere to the left of @xmath175 is of colour @xmath184 .
this piece may overlap ( in the sense of occupying some pieces with the same @xmath162 ) with the piece @xmath196 , also of colour @xmath184 , which is in column @xmath197 .
we can see @xmath182 will not also overlap with the pieces @xmath198 ( also of colour @xmath184 ) in columns @xmath199 for the following reasons : ( 1 ) it is smaller than @xmath181 and hence can only partly overlap with the piece @xmath200 ( of colour @xmath188 ) in column @xmath175 in fig .
[ fig7 ] ; ( 2 ) this piece of colour @xmath188 in column @xmath175 does not overlap with the colour @xmath184 in columns @xmath201 . hence
, this problem only concerns piece @xmath182 and column @xmath197 .
let us assume that piece @xmath182 is in column @xmath202 and that the original colour of column @xmath202 is @xmath203 .
we can use colour @xmath203 to correct for piece @xmath182 in @xmath202 and @xmath196 in @xmath197 by essentially the same correcting procedure as before .
thus , we swap a piece of @xmath203 and of area @xmath204 from @xmath202 to into @xmath196 in @xmath197 and at the same time swap a piece of colour @xmath184 and of area @xmath204 from @xmath196 in @xmath197 into @xmath202 . the areas @xmath182 and @xmath204 are collected together at the top of column @xmath175 .
the size of area @xmath204 is chosen to be just such that @xmath205 ( which is of colour @xmath184 ) no longer overlaps with any of the colour @xmath184 in @xmath197 .
the maximum size of area @xmath204 is given by @xmath206 we could have @xmath204 smaller than the value given by this equation since it is possible that not all of @xmath182 overlaps with @xmath196 in @xmath197 .
hence , @xmath207 this correcting procedure is carried out in the following way .
first the rightmost bunch of columns like @xmath176 and @xmath175 are selected .
then the directly swapped pieces are corrected .
and then the swapped back pieces are corrected .
then the next bunch of columns are subject to the same correcting protocol until all the bunches have been corrected .
if this procedure can be carried out successfully then we will have solved this colouring problem
. the only possible problem would be if we had to swap more of the colour @xmath184 from @xmath175 than there is in the column .
however , we can show that this will not happen . from the fig .
[ fig7](a ) we see that the area , @xmath208 , of the original colour @xmath184 in @xmath175 satisfies @xmath209 the inequality must be satisfied since otherwise elements of colour @xmath188 in row @xmath175 will be in the same row as elements of colour @xmath188 in row @xmath197 but we proved in sec .
b. that this could not happen with this colouring of the diagram . from ( [ props],[higher ] )
we obtain @xmath210 since @xmath182 had to be corrected for , @xmath11 must also be corrected for ( if @xmath175 and @xmath176 are taken to represent a general bunch of columns ) . to correct for
@xmath11 will require an area @xmath190 of colour @xmath184 to be swapped into a column @xmath211 somewhere on the right .
by analogy with ( [ wpmax ] ) we have @xmath212 where the second inequality follows since @xmath213 .
hence , @xmath214 which means that there is enough of the colour @xmath184 in column @xmath175 to complete this colouring strategy .
hence , the colouring problem has been solved .
we need to prove that nielsen s bound can not be beaten .
this is equivalent to proving that it is not possible to have net movement of area down the area diagram .
the start state corresponds to a step structure .
each column in this can be divided up into @xmath159 pieces as shown in fig .
next we collect together all the pieces corresponding to a given @xmath162 and place them in order along the @xmath42 axis as shown in fig .
[ fig8 ] .
thus , going along the @xmath42 axis we have the @xmath215 pieces , then the @xmath216 pieces and so on .
this can be accomplished by alice performing swap operations .
we will call this the _ mini - step form _ for the area diagram .
( we are , of course , assuming that system @xmath12 has a large enough hilbert space to be able to do this .
if this is not the case then an additional ancilla could be introduced to effectively increase the size of @xmath12 s hilbert space . )
let the state corresponding to this diagram be @xmath217 .
now we change from the @xmath38 to the @xmath105 picture where @xmath103 is the @xmath103 in @xmath104 .
the @xmath105 element can only be moved up and down the diagram when alice performs local operations .
hence , in the @xmath105 picture all the mini - steps will overlay each other so there will be @xmath159 elements at each position
. the height of the @xmath103th column will be @xmath218 .
hence , if we define @xmath219 , then for the start state @xmath217 we have @xmath220 for all @xmath221 .
the factor @xmath159 comes from the fact that there are @xmath159 sets of mini - steps overlaying each other in the @xmath105 picture .
now we go back to the @xmath38 picture and consider the target state ( [ targetg ] ) .
we can apply the transformation @xmath222 to @xmath223 ( we set @xmath224 ) .
we will let @xmath164 . under this transformation ( [ targetg ] )
becomes latexmath:[\[\label{targetf } equal to @xmath16 for @xmath226 .
this state now consists of a number of terms @xmath227 each having the same amplitude @xmath228 . each term , @xmath227 ,
can individually be put into the step form @xmath229 ) .
if this transformation is applied to all terms then the resulting area diagram will consist of a series of mini - steps lined up vertically as shown in fig .
[ fig9 ] . next , alice applies swap operations to move these sets of mini - steps so that they are lined up along the @xmath42 axis starting with the @xmath215 pieces giving an area diagram in mini - step form ( like in fig .
[ fig8 ] ) .
the state becomes @xmath230 for any normalised state @xmath98 .
the problem is to go from the start diagram in mini - step form to the target diagram which is also in mini - step form .
if and only if we can do this can we also go between the corresponding diagrams in standard step form since alice can transform reversibly between the two types of form of the area diagram .
if there is to be net movement of area downwards in the mini - step form then this must happen for at least one value of @xmath103 .
hence , comparing with ( [ initiala ] ) , net downward movement of area implies @xmath231 for at least one value of @xmath103 and @xmath232 .
however , ( [ thetaarea ] ) implies @xmath233 which contradicts ( [ nbigarea ] ) and hence there can be no net movement of area downwards in the mini - step form .
the standard step form area diagrams are simply elongated versions of one set of mini - steps in the mini - step form , and hence , by the similarity of these shapes , there can be no movement of area downwards in the standard picture .
this proves nielsen s bound ( given algebraically in ( [ newsteps ] ) ) .
in this paper a method of areas has been developed which enables us to understand the manipulation of pure two - particle entanglement .
this approach has been used to find the most general way of transforming a general two - particle pure state into maximally entangled states .
certain results of lo and popescu were given geometric interpretations .
this method has also been used to prove nielsen s theorem which pertains to going from one two - particle pure state to another with certainty .
there remain a number of open problems relating to manipulation of two - particle pure entanglement which it may be possible to solve using the method of areas .
firstly , we could generalise nielsen s theorem to the problem where we go from one state to another but not necessarily with certainty . secondly
, we could consider the problem of going from one state to a distribution of states .
the method may also generalise to more than two particles ( though it is not presently clear how this generalisation will work ) .
i am grateful to anna mahtani for suggesting a way to solve the second colouring problem and to daniel jonathan for comments relating to section 2.4 in an earlier version .
i would also like to thank the royal society for funding .
note : g. vidal pointed out to the author that he had already solved @xcite the first open problem mentioned in the conclusion .
the second open problem has been solved by d. jonathan and m. plenio @xcite in work done independently of the present work .
they also use their result to give a derivation of equation ( [ emax ] ) . in this appendix
we show that there can be no advantage if alice makes a non - maximal rather than a maximal measurement onto @xmath11 .
assume that the state just before measurement is @xmath234 where @xmath235 is some state of system @xmath236 and not necessarily an @xmath9-state .
imagine that the projective measurement is non - maximal and one of its projectors is @xmath237 .
in the case of having the corresponding outcome , the resulting ( unnormalised ) state will be @xmath238 this could , for example , be an @xmath9-state if system @xmath11 is regarded as being part of system @xmath12 .
rather than performing this non - maximal measurement alice could instead change her notation for the @xmath23 states such that , if @xmath23 appears in the expansions of @xmath239 and @xmath240 she writes @xmath23 as @xmath241 .
the remaining vectors @xmath23 are relabelled as @xmath242 .
we are free to assume that the dimension of @xmath12 is big enough to do this
. then we write @xmath243 .
now alice performs the transformations @xmath244 @xmath245 under these transformations the first two terms in ( [ gen ] ) become @xmath246 a maximal measurement will now give rise to a state with the same form as the state as in ( [ non ] ) for the outcome 2 .
this trick can be repeated everywhere there is a degeneracy in the original non - maximal measurement and a maximal measurement can then be performed instead .
this maximal measurement will give rise to the same distribution of the same states as the non - maximal measurement and so there can be no advantage to performing non - maximal measurements . c. h. bennett , g. brassard , c. crepeau , r. jozsa , a. peres , w. k. wooters , phys .
lett . * 70 * , 1895 ( 1993 ) .
see c. h. bennett and p. w. shor , ieee transactions on information theory * 44 * , 2724 ( 1998 ) and references therein r. cleve and h. buhrman , phys .
a * 56 * , 1201 ( 1997 ) . c. h. bennett , h. j. bernstein , s. popescu , and b. schumacher , phys .
a. * 53 * , 2046 ( 1996 ) .
h - k lo and s. popescu , concentrating entanglement by local actions - beyond mean values , report no .
quant - ph/9707038 m. a. nielsen , a partial order on the entangled states , report no .
quant - ph/9811053 .
an alternative solution to this colouring problem can be deduced from the fact , used by nielsen in @xcite , that any doubly stochastic matrix may be written as a product of finitely many @xmath72-_transforms_. these @xmath72-_transforms _ correspond to a cut and paste operation on two columns in which the same proportion @xmath247 is cut from each column and added to the other .
g. vidal , entanglement of pure states for a single copy , report no .
quant - ph/9902033 .
see also g. vidal , entanglement monotones , report no .
quant - ph/9807077 .
d. jonathan and m. plenio , minimal conditions for local pure - state entanglement manipulation , report no .
quant - ph/9903054 . | we consider the problem of how to manipulate the entanglement properties of a general two - particle pure state , shared between alice and bob , by using only local operations at each end and classical communication between alice and bob .
a method is developed in which this type of problem is found to be equivalent to a problem involving the cutting and pasting of certain shapes along with certain colouring problems .
we consider two problems .
firstly , we find the most general way of manipulating the state to obtain maximally entangled states .
after such a manipulation the entangled states @xmath0 are obtained with probability @xmath1 .
we obtain an expression for the optimal average entanglement obtainable . also , some results of lo and popescu pertaining to this problem are given simple geometric proofs .
secondly , we consider how to manipulate one two - particle entangled state @xmath2 to another @xmath3 with certainty .
we derive nielsen s theorem ( which states a necessary and sufficient condition for this to be possible ) using the method of areas . |
supplementary material is available for this article at doi : 10.1007/s11606 - 007 - 0303 - 4 .
chronic illnesses are a high priority for health care systems because they are costly , complex to manage , and result in substantial disability . chronic illness is extremely common : almost half of all americans , more than 100 million people , live with a chronic condition .
half of those affected , more than 50 million , are living with more than one chronic illness .
costs for chronic illness care are approximately 80% of total health care costs , and rising.1 despite these expenditures , the quality of care for chronic illness is often poor.2,3 treatments known to be beneficial are provided only about 50% of the time , and inappropriate treatments are provided as much as 30% of the time.4 one problem is that health care organizations often utilize care models that respond well to acute problems , but are poorly designed for chronic illness care . in prevailing care models , clinicians have to focus brief visits on acute problems , crowding out time to attend to chronic disorders . follow - up care is poorly coordinated , communication breakdowns are common , and patients often lack key skills and information they need to self - manage their illnesses.1,5,6 one leading approach to improving care for chronic illness is to implement collaborative or chronic care
models.5,7,8 these care models use a longitudinal , team - based approach , and reorganize care to improve collaboration between an informed , activated patient and a prepared , proactive care team .
chronic care models that integrate patient information , clinical care management , and evidence - based treatments have been shown to improve patient outcomes.9 however , there are formidable obstacles to implementing these care models , and their use has been limited . improving information flow , both between patient and provider and among providers , is a prerequisite , but the complexity of transmitting knowledge and patient information within the treatment environment has been a challenge.10,11 health information technologies ( hit ) , such as electronic medical records ( emrs ) , can efficiently improve information flow.12,13 indeed , hit is specified as critical to implementation of many chronic care models.14 although most physicians in the united states still do not use comprehensive emrs , emrs are now common in large provider organizations and many smaller organizations have adopted focused informatics tools.1517 whereas current hit systems are often organized similar to paper charts , the diversity of potential systems is enormous .
this has contributed to considerable uncertainty regarding which specific informatics components and strategies improve chronic illness care , slowing development and implementation efforts .
there has been extensive practical experience with hit.1821 two relevant domains of hit in chronic illness care are emrs and personal health records ( phrs ) .
emrs have been developed to support the operations of health care providers , whereas phrs provide services to patients and help them manage their health care data and illnesses.22,23 although research on phrs is limited , there is substantial research on emrs .
recently , a committee of the institute of medicine ( iom ) identified eight domains of care delivery that emr systems should perform : health information / data , results management , order entry , decision support , communication and connectivity , patient support , administrative process , reporting , and population health.22 despite an extensive body of research , in practice , emr systems can be limited in their scope , or become complex and unwieldy.24 also , prevailing systems often lack functions that support chronic illness care , such as disease registries , the capability to monitor panels of patients , facilitation of team communication , execution of treatment plans across primary and specialty care lines , and transition from text notes to computable fields .
this manuscript presents results from creating health informatics applications for collaborative care ( chiacc ) , a project to increase consensus regarding informatics technologies that support improvement in chronic illness care .
primary funding for chiacc was provided by the department of veterans affairs ( va ) .
the va operates the largest integrated health care system in the united states a system with a comprehensive , fully computerized emr.18,25,26 the goals of chiacc were to understand how informatics can support improvement in the quality of care and to inform next steps in software development for organizations that have moved or are moving from paper - based to electronic records .
the project consisted of four linked phases : ( 1 ) establish a steering committee to guide the project and discuss potential informatics components and strategies , ( 2 ) review the literature on informatics that could improve chronic illness care , ( 3 ) develop use cases that exemplify the complexities of chronic illness care , and ( 4 ) increase expert consensus regarding informatics components and strategies , taking into account the strengths and weaknesses of software previously developed , used , and evaluated .
establish directions and priorities.januaryfebruary 2005steering committee individual interviews by phoneelicit potential domains to be included in software .
elicit strategies for having the expert panel rate domains.february 2005steering committee meets by phoneprovide summary of individual interviews and finalize expert panel membership.started march 2005 ; published april 2007literature reviewcharacterize information systems components important in supporting improved care of chronic illness.june 2005use case developmentdevelop use cases for depression , schizophrenia , diabetes , and comorbid disorders.julyaugust 2005expert panel communication via emailpresent summary of literature review and draft use cases .
increase consensus on software components and functions.october 2005use cases finalizedrevise and finalize use cases based on expert panel discussions.july 2006steering committee meets by phonepresent expert panel consensus , and finalize use cases .
chiacc study timeline the chiacc project was guided by a 10-member multidisciplinary steering committee that had broad representation from va and non - va stakeholders in a variety of medical specialties and information systems .
members included physician experts in chronic diseases such as hypertension and depression , and individuals with expertise in improving the quality of care and information systems .
the steering committee was tasked with ensuring that the project was consistent with national directions in improving care for chronic illness , and with prevailing information systems , including the va national emr .
the committee decided to adopt the eight iom informatics functional domains22 and to study whether these domains wholly captured software components that improve chronic illness care .
the steering committee members gave feedback on the utility of each of the iom domains and suggested additional functions they felt were important to the system within each domain .
for example , the iom domain of decision support includes computerized reminders and prompts , computer - assisted diagnosis , and access to treatment guidelines .
the committee could add , real time interpretation of patient unmet needs as critical and fitting within this domain .
a systematic review of the literature was undertaken , covering studies evaluating information systems used in chronic illness care.19 the review searched the literature from 19962005 .
the primary goal was to understand which informatics components support best practices and which have the highest likelihood of successful implementation .
building on the findings of the steering committee interviews and literature review , use case models
these disorders were chosen because of their high priority nationally , their fit with project objectives , and to include attention to comorbidity , which is the norm in chronic illness .
the va has a national quality enhancement research initiative ( queri ) program , which is designed to translate research discoveries into better patient care and systems improvements.27 there are nine queri programs , each focused on high - risk or highly prevalent disorders . for each use case ,
a workgroup was convened , with leadership from chiacc and the relevant queri programs ( i.e. , mental health and diabetes ) .
each workgroup drew on results from the literature review and expert interviews , and on the clinical and research experience of the relevant queri program , in constructing their use case .
this process resulted in draft use cases that became a foundation for the expert panel discussion , and began an iterative process of use case development .
an expert panel was formed to increase consensus regarding informatics system needs for improving chronic care .
consensus was necessary given ( 1 ) the literature review did not result in clear direction for software development and ( 2 ) the domains and function of software modules needed to be prioritized with the goal of serving multiple comorbid conditions .
the panel process used a modified delphi approach , and built consensus using iterative feedback on each proposed use case.28,29 on any given informatics component , we sought agreement among the vast majority of panelists , but did not insist on complete agreement from all panelists .
the composition of the expert panel included clinicians treating diabetes , depression , schizophrenia , and comorbid conditions ; quality improvement and disease management experts ; information system developers ; and health care managers and policymakers .
experts were drawn from va , the substance abuse and mental health services administration , and the health care industry .
diverse experience was important because a goal was to consider software modules that are consistent with emrs and informatics developments nationally . before the expert panel meeting
, panel members were provided with results from the literature review and the initial use cases .
the panel provided feedback on the use cases , and a second version of the use cases were made based on this feedback . at the in - person expert panel meeting in the fall of 2005 ,
the second version of the use case models were presented and used to guide a discussion regarding requirements of informatics modules to support improvement in chronic illness care .
diabetes , depression , schizophrenia , and comorbidity were each discussed separately , with each discussion led by a clinician researcher expert in the disorder .
detailed minutes were taken by two research assistants . at the close of discussion of each disorder ,
after all diseases had been discussed , the lists for each disease were combined and reprioritized for a final list of priorities for software components to address chronic illness generally .
after the expert panel meeting , the lists for each disease were used to revise the use case models into a final version that could be used to inform software development .
use cases the use case methodology is an iterative process often used in hit and other informatics development.30,31 the goal is to capture the requirements inherent in a system s response to primary actors . whereas there are various ways to document a use case , a common approach is to write a structured story that describes how the informatics systems assist in certain behaviors .
a use case describes system functionality and is referred to at all stages in the software development process : programmers create a software prototype based on the use case , developers then review each successive prototype for conformance to the use case , and field testing ensures that the prototype correctly implements the use case .
whereas this project also developed use cases for depression and schizophrenia , the diabetes use case is discussed here in detail because it provides the best example of chronic illness care that includes comorbidity.a use case begins with a vision for the behaviors described .
for chiacc , the vision was to improve the quality of care through implementation of guideline - concordant treatments .
these were the primary care provider , clinical care manager , specialists who provide consultation , and the patient .
the trigger that activates the use case is described , and the flow of behaviors and events that follow from that trigger are outlined , including various optional conditions . in the diabetes use case , a trigger occurs when a primary care provider diagnoses diabetes and refers a patient to care management for initial assessment , education , and follow - up . another trigger to activate the use case would occur when a care manager identifies a patient at high risk for diabetes in need of more intensive education , treatment , or monitoring and initiates a visit or phone call with the patient .
then a typical course of events follows , with highlighting of areas where hit can provide improved care of quality . in diabetes , the use case describes separate visits with the medical assistant , the primary care provider , and the care manager , and the resulting communication among this team and with the patient .
in addition , there is information about tracking the patient s progress and population management .
the use case illustrates how hit can be used to support quality care through components such as a comprehensive care plan , lab value and medication alerts , improved provider communication , and tracking of patient outcomes .
the use case provides alternative pathways when , for example , a patient is particularly noncompliant or especially self - motivated and activated .
the domain rated lowest in utility was administrative processes and the highest was health information and data .
the steering committee added a number of additional features to the it domains , with each domain acquiring several additions overall .
for example , the iom defines health information and data as , electronic storage and immediate access to diagnoses , allergies , lab test results , medications , clinical notes , demographics .
committee members added several items , including patient assessment and surveys , routine outcomes assessments , and results of ongoing assessments .
results from the literature review have been published.19 much of the literature is nonexperimental . in studies with experimental designs , components related to positive outcomes
are connection to an emr , computerized prompts , population management , specialized decision support , electronic scheduling , and patient health records .
this is consistent with some previous , broader reviews.21,32 the expert panel agreed that information systems should be patient - centered and emphasize patient preferences , functioning , and quality of life .
the recovery model , which was originally developed for mental health,33 was seen as applicable to other chronic medical disorders .
this recovery model emphasizes the importance of moving beyond disease alone to strategies for supporting individuals with chronic illness as they work toward life goals and aspirations.34 the panel agreed that the routine assessment of critical outcomes was necessary , using reliable , valid , and commonly used measures such as the nine - item scale of the patient health questionnaire for depression or blood pressure for hypertension.35 choice of outcomes should be guided by quality improvement priorities .
the panel recommended using automatic scoring algorithms to link problematic outcomes scores to appropriate treatment recommendations and agreed that these results should be easily accessible and interpretable by providers at the time of the clinical encounter .
there were several ideas for displaying these results , such as a timeline graphing scores against medication trials , clinical encounters , and landmark events .
there have been published informatics tools that graph blood pressure against antihypertensive medications on a timeline.36 outcomes data should also be usable for population - based improvement of health care quality .
a key problem with current emrs is information overload , and data presentation that does not efficiently meet the needs of providers in complex cases . in response , the panel stated that there should be an interactive , sequential , and comprehensive treatment plan in the emr .
each medical condition in the patient s problem list would be accompanied by a clinical care pathway , which could be used by clinicians to quickly identify the current stage of treatment for each of the patient s problems in relation to best - practice algorithms .
for example , in the management of depression , the care pathway could start with initiation of either antidepressant medication or psychotherapy , then proceed to intensifying the treatment , and trying alternative or combination treatments for patients failing to respond .
the treatment plan would clearly indicate which phase of treatment the patient is in , and how long they had been there .
outcome indicators , such as depression severity , could be graphically displayed in relation to treatment trials . with regard to the diabetes use case
, panel members agreed that communication , collaboration , and coordination of care among all providers is critical to improving care .
a method such as an electronic flow sheet to track steps in care over time would be beneficial to the coordination of diabetes care .
panel members believed that there is a need for scheduling long - term care needs ( such as eye exams and foot care for diabetes ) and that a tickler alert system would be ideal for long - term , automated scheduling .
another recommendation was structured , automated templates for progress notes , allowing providers to easily report and access critical information regarding treatment history and planned treatment steps .
the panel agreed that templates with functionalities such as guideline - based checklists for providers could enhance diabetes care .
other suggestions that were endorsed by the panel included creating provider alerts for gaps in prescription refills to target issues with medication adherence , and creating a system of automated phone messages for patients , reminding them of appointments and medication refills .
panel members emphasized that the treatment plan should include each of the patients medical conditions , whereas allowing for prioritization of problems .
accessing one medical condition , for example , diabetes , could trigger the display of other important and related comorbid conditions , such as hyperlipidemia , as well as the display of relevant labs and outcome measures .
furthermore , panel members believed that the treatment plan should list all providers and care managers associated with each condition and be shared across treatment sites . because comorbidity is very common in diabetes care , the decision was made to merge the diabetes and comorbidity use cases .
the use cases were revised based on results from the panel , and the final versions are available online ( doi http://dx.doi.org/10.1007/s11606-007-0303-04 ) .
the science of chronic illness care is rapidly advancing , and there is increasing pressure to improve the quality and efficiency of care for these disorders .
there is also rapid evolution in health informatics tools that help improve chronic illness care . because research on the effectiveness of specific informatics tools is inadequate to definitively characterize hit needs , and will likely remain so , this project made use of a national expert panel process to increase consensus in this area . whereas hit can serve diverse agendas , the focus here was on hit as a tool to improve the quality of care .
the va has one of the largest and most successful quality improvement systems in health care nationally,2 and this project drew heavily from that experience . with this focus ,
given the prevalence of comorbidity , and the need to manage care over time , the panel recommended that an interactive , sequential , disorder - specific treatment planning pathway system be central to hit development efforts . to do this , treatment algorithms will need to be implemented in software . because informatics should be patient - centered and recovery - oriented , critical outcomes need to be routinely assessed and retrievably coded . with this approach
, decision support systems can quickly show the clinician where the patient is in their longitudinal treatment plan , present the history of outcomes and treatment use , and provide guidance regarding current treatment options .
data can also be useful to managers and policymakers to characterize workflow and inform quality improvement efforts .
successful use of hit to improve chronic illness care requires attention to specific implementation issues and strategies.37,38 for example , many physicians in the us still do not use an emr , and communication among the panoply of hospital and community providers electronic systems is woefully inadequate . whereas emrs can be powerful tools to improve the quality of care ,
their implementation is neither easy nor cheap , and barriers are especially high for solo and small group providers .
a recent review of hit implementation concluded that developers need to consider structural , financial , policy - related , cultural , and organizational barriers to implementation and strategies to overcome them.11 cost can be a barrier when hit supports implementation of evidence - based practices .
many evidence - based strategies , such as the chronic care model , rely on care managers , nurses , and other nonphysician staff to provide ongoing , assertive management of disease .
however , typical reimbursement mechanisms were not designed for this purpose , rendering implementation prohibitively expensive .
hit can provide some help in this regard , minimizing staff costs , detecting errors , and maximizing efficiency and coordination of care.14 also , for organizations that have a staged approach to implementing hit , software to support chronic illness care can be an early step in the process of emr implementation .
this can have an impact on quality with lower cost burden than a full emr .
much of the research on use of hit is nonexperimental and relatively few studies have examined quality of care as an outcome . substantially more research is needed , and , when possible , experimental designs should be employed . however , much of hit development occurs outside the context of research studies , in support of specific projects or clinical missions . in these situations
, it will be important to use robust formative research methods that include usability testing but also go beyond it to evaluate the role of information systems in clinical and policy efforts to improve care.39 in this project , the expert panel process resulted in the development of use cases for depression , schizophrenia , and diabetes with comorbidity . because informatics development , usability testing , and the evaluation of informatics effectiveness are iterative processes , these use cases are not final versions but rather a step toward ongoing informatics development .
use cases will need to be modified as the science of quality improvement evolves , and as more research is done on pay for performance and other strategies .
they will also need to be adapted to the needs of the specific clinicians , organizations , the patient populations they serve , and the quality improvement strategies that are used .
there may also need to be modifications as phrs become more widely used and studied .
further informatics development work will certainly be needed to extend emrs and phrs in new directions
. therefore , software needs to be flexible enough to support and incorporate new findings about how to improve care for patients .
chiacc illustrated the value of bringing together policymakers as well as experts in implementation science and hit to inform software development . to broadly improve chronic illness care ,
hit must be consistent with organizational and population - based efforts to improve treatment quality , and meet the needs of clinicians and clinic staff .
it is quite challenging to simultaneously meet the needs of the wide variety of hit stakeholders , and there are numerous examples of hit systems that have not had broad impact or that have failed to meet expectations .
informatics has the potential to substantially improve chronic illness care . to fully achieve this potential , hit development should be integrated with a systematic approach to health care quality improvement and implementation science
| backgroundin populations with chronic illness , outcomes improve with the use of care models that integrate clinical information , evidence - based treatments , and proactive management of care .
health information technology is believed to be critical for efficient implementation of these chronic care models .
health care organizations have implemented information technologies , such as electronic medical records , to varying degrees .
however , considerable uncertainty remains regarding the relative impact of specific informatics technologies on chronic illness care.objectiveto summarize knowledge and increase expert consensus regarding informatics components that support improvement in chronic illness care .
design : a systematic review of the literature was performed .
use case models were then developed , based on the literature review , and guidance from clinicians and national quality improvement projects . a national expert panel process was conducted to increase consensus regarding information system components that can be used to improve chronic illness care.resultsthe expert panel agreed that informatics should be patient - centered , focused on improving outcomes , and provide support for illness self - management .
they concurred that outcomes should be routinely assessed , provided to clinicians during the clinical encounter , and used for population - based care management .
it was recommended that interactive , sequential , disorder - specific treatment pathways be implemented to quickly provide clinicians with patient clinical status , treatment history , and decision support.conclusionsspecific informatics strategies have the potential to improve care for chronic illness .
software to implement these strategies should be developed , and rigorously evaluated within the context of organizational efforts to improve care.electronic supplementary materialsupplementary material is available for this article at doi : 10.1007/s11606 - 007 - 0303 - 4 . |
a 13-year - old girl had a history of partial atrioventricular septal defect ( pavsd ) total correction at the age of 4 years .
however , a right ventricular assist device was applied at the operation because of the akinetic right ventricle ( rv ) .
two years later , based on our echocardiography results , the patient was transferred due to severe tricuspid regurgitation and rv chamber enlargement with rv dysfunction .
she underwent tricuspid septal commissuroplasty , de vega - type tricuspid annuloplasty , right atrial reduction plasty , and isthmus ablation .
further , we performed one - and - a - half ventricle repair . in spite of the operation ,
six years after the one - and - a - half ventricle repair , cardiac magnetic resonance imaging was performed to evaluate her cardiac function and measure the left ventricle ( lv ) volume .
the patient s rv end diastolic volume index and rv ejection fraction were 500.4 ml / m , and 13.2% , respectively .
the lv stroke volume index and ejection fraction were 38.2 ml / m and 28% , respectively .
echocardiographic evaluation showed global rv akinesia and lv ejection fraction of 25% with paradoxical interventricular septal motion .
we suspected that the rv enlargement affected both the rv and the lv function and it resulted in decreased lv contractility .
she underwent extracardiac conduit fontan operation with polytetrafluoroethylene ( ptfe , gore - tex ; wl gore & associates , flagstaff , az , usa ) 24-mm tube graft , rv exclusion , atrial septectomy , and permanent pacemaker implantation .
rv exclusion procedures include tricuspid valve obliteration ( from the rv side ; 5 - 0 prolene double layer , reinforcement suture from the ra side ; 4 - 0 polyester ptfe pledget - supported interrupted mattress suture ) and pulmonary valve obliteration ( 6 - 0 prolene running suture ) to reduce the rv volume with no flow connection , thrombin soaked gel - foam packing to the rv , and rv free - wall wide resection , and it was performed under the condition of cardiac arrest ( fig .
permanent pacemaker bipolar leads were implanted at the lv apex , rv apex , left atrial roof , and ra free wall owing to a history of frequent atrial flutter and junctional rhythm .
we did not perform arrhythmia surgery because the patient underwent an electrophysiology study and radiofrequency catheter ablation for supraventricular arrhythmia before the operation .
the cardiopulmonary bypass time was 308 minutes , and the aortic cross clamp time was 146 minutes .
we performed the computed tomographic angiography not cardiac magnetic resonance imaging to evaluate the patient s postoperative cardiac function and chamber size , because she was implanted with a permanent pacemaker .
the rv volume was markedly reduced , and the rv was occluded with thrombosis ( fig .
further , the stroke volume index and the ejection fraction of lv were increased to 48.03 ml / m and 33% , respectively ( table 1 ) .
the patient s vital signs were stable with a central venous pressure of 18 to 21 mmhg .
she was extubated in 14 hours , and she stayed in the intensive care unit for 90 hours .
we removed the chest tubes 5 days later , and she was discharged on postoperative day 21 .
she has been followed up for 21 months without any complaint of dyspnea and palpitation .
3 ) , and in the latest echocardiography , the ejection fraction of the lv had increased to 54% .
recently , the importance of rv failure has been noted , in light of the incomplete understanding of the rv failure mechanism and a poorer prognosis than lv failure has .
further , it has been reported that an increased rv volume and decreased ejection fraction are associated with lower survival rates in patients with congestive heart failure .
the rv volume overload is one of the causes of right ventricle failure ( rvf ) .
further , it is known that the rv volume over load leads to the leftward displacement of the interventricular septum and changes in the lv geometry , thus resulting in decreased lv contractility .
, several reports have shown the successful outcome of the original and the modified rv exclusion procedures in the case of ebstein s anomaly .
. she could have lived in a biventricular state if she had undergone the total correction of pavsd at the appropriate time . however , this case is meaningful in determining how to manage patients with rvf .
we performed an rv exclusion to normalize the motion of the interventricular septum by reducing the rv volume .
further , we demonstrated that both the end diastolic volume index and the stroke volume index increased after the operation .
another beneficial effect of rv exclusion is lung expansion , because an enlarged heart can compress the lungs .
in addition , adequate lung expansion helps to reduce pulmonary vascular resistance , and decreased pulmonary vascular resistance is a good prognostic factor among functional univentricular patients . in conclusion ,
the rv exclusion procedure in selected patients with severe rvf might be a safe and beneficial option to improve lv function . | a 13-year - old girl , who had undergone the total correction of partial atrioventricular septal defect at the age of 4 years , was admitted with severe tricuspid regurgitation in echocardiography .
she had received one - and - a - half ventricle repair during follow - up .
her right ventricle showed global akinesia , and the ejection fraction of the left ventricle was 25% with paradoxical interventricular septal motion .
we performed right ventricular exclusion adjunct to the fontan procedure .
she is doing well two years after the operation without complications . |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Transportation Safety Program
Extension Act of 2003''.
SEC. 2. EXTENSION OF MOTOR CARRIER SAFETY PROGRAM.
(a) Administrative Expenses.--There shall be available from the
Highway Trust Fund (other than the Mass Transit Account) for the
Secretary of Transportation for administration of motor carrier safety
programs, motor carrier safety research, and border enforcement
activities, including the border enforcement program authorized under
section 350 of the Department of Transportation and Related Agencies
Appropriations Act, 2002, $119,125,000 for the period beginning on
October 1, 2003, and ending on February 29, 2004, to carry out the
functions and operations of the Federal Motor Carrier Safety
Administration of which $19,583,000 shall be available for the
construction of State border safety inspection facilities at the border
between the United States and Mexico and at the border between the
United States and Canada and of which $4,583,000 shall be used for
regulatory development.
(b) Motor Carrier Safety Account.--Funds made available under
subsection (a) shall be administered in the account established in the
Treasury entitled ``Motor Carrier Safety 69-8055-0-7-401''.
(c) Maintenance of Expenditures.--The Secretary of Transportation
may make a grant under section 31107 of title 49, United States Code,
to a State from funds made available under subsection (a) only if the
State agrees that the total expenditure of amounts of the State and
political subdivisions of the State, exclusive of United States
Government amounts, will be maintained at a level at least equal to the
average level of that expenditure by the State and political
subdivisions of the State for the last 2 fiscal years before October 1,
2003.
(d) Contract Authority.--Funds made available under subsection (a)
shall be available for obligation in the same manner as if such funds
were apportioned under chapter 1 of title 23, United States Code.
SEC. 3. EXTENSION OF MOTOR CARRIER SAFETY ASSISTANCE PROGRAM.
(a) Motor Carrier Safety Assistance Program.--Section 31104(a) of
title 49, United States Code, is amended by adding at the end the
following:
``(7) Not more than $77,125,000 for the period beginning on
October 1, 2003, and ending on February 29, 2004.''.
(b) Information Systems.--Section 31107(a) of title 49, United
States Code, is amended--
(1) by striking ``and'' after the semicolon in paragraph
(2);
(2) by striking ``2002.'' in paragraph (3) and inserting
``2002;'';
(3) by striking ``2003.'' in paragraph (4) and inserting
``2003; and''; and
(4) by adding at the end the following:
``(5) $8,333,000 for the period beginning on October 1,
2003, and ending on February 29, 2004.''.
(c) Maintenance of Expenditures.--The Secretary of Transportation
may make a grant to a State from funds made available under section
31104(a)(7) of title 49, United States Code, only if the State agrees
that the total expenditure of amounts of the State and political
subdivisions of the State, exclusive of United States Government
amounts, will be maintained at a level at least equal to the average
level of that expenditure by the State and political subdivisions of
the State for the last 2 fiscal years before October 1, 2003.
SEC. 4. EXTENSION OF HIGHWAY SAFETY PROGRAMS.
(a) Chapter 4 Highway Safety Programs.--Section 2009(a)(1) of the
Transportation Equity Act of the 21st Century (112 Stat. 337) is
amended--
(1) by striking ``and''; and
(2) by striking ``2003.'' and inserting ``2003, and
$68,640,000 for the period beginning on October 1, 2003, and
ending on February 29, 2004.''.
(b) Highway Safety Research and Development.--Section 2009(a)(2) of
that Act (112 Stat. 337) is amended by striking ``2003.'' and inserting
``2003, and $29,952,000 for the period beginning on October 1, 2003,
and ending on February 29, 2004.''.
(c) Occupant Protection Incentive Grants.--Section 2009(a)(3) of
that Act (112 Stat. 337) is amended--
(1) by striking ``and''; and
(2) by striking ``2003.'' and inserting ``2003, and
$8,320,000 for the period beginning on October 1, 2003, and
ending on February 29, 2004.''.
(d) Incentive Grants for Alcohol-Impaired Driving Counter-
Measures.--
(1) Extension of program.--Section 410 of title 23, United
States Code, is amended--
(A) by striking ``6'' in subsection (a)(3) and
inserting ``7''; and
(B) by striking ``fifth and sixth'' in subsection
(a)(4)(C) and inserting ``fifth, sixth, and seventh''.
(2) Authorization of appropriations.--Section 2009(a)(4) of
the Transportation Equity Act of the 21st Century (112 Stat.
337) is amended--
(A) by striking ``and'' the last place it appears;
and
(B) by striking ``2003.'' and inserting ``2003, and
$16,640,000 for the period beginning on October 1,
2003, and ending on February 29, 2004.''.
(e) National Driver Register.--Section 2009(a)(6) of that Act (112
Stat. 338) is amended by striking ``2003.'' and inserting ``2003, and
$1,498,000 for the period beginning on October 1, 2003, and ending on
February 29, 2004.''.
(f) Allocations.--Section 2009(b) of that Act (112 Stat. 338) is
amended by striking ``2003,'' each place it appears and inserting
``2004,''.
(g) Applicability of Title 23.--Section 2009(c) of that Act (112
Stat. 338) is amended by striking ``2003'' and inserting ``2004''.
SEC. 5. EXTENSION OF SPORT FISHING AND BOATING SAFETY PROGRAM.
Section 13106 of title 46, United States Code, is amended by
striking subsection (c) and inserting the following:
``(c) Boating Safety Funds.--
``(1) In general.--Of the amount transferred to the
Secretary of Homeland Security under paragraph (4) of section
4(b) of the Dingell-Johnson Sport Fish Restoration Act (16
U.S.C. 777c(b)), $2,083,333 is available to the Secretary for
payment of expenses of the Coast Guard for personnel and
activities directly related to coordinating and carrying out
the national recreational boating safety program under this
title, of which $833,333 shall be available to the Secretary
only to ensure compliance with chapter 43 of this title.
``(2) Use of funds.--No funds available to the Secretary of
Homeland Security under this subsection may be used--
``(A) to replace funding traditionally provided
through general appropriations; or
``(B) for any purposes except a purpose authorized
by this section.
``(3) Availability of funds.--Amounts made available by
this subsection shall remain available until expended.
``(4) Accounting.--The Secretary shall publish annually in
the Federal Register a detailed accounting of the projects,
programs, and activities funded under this subsection.''. | Transportation Safety Program Extension Act of 2003 - Makes specified Highway Trust Fund amounts available for the period of October 1, 2003, until February 29, 2004, for the Secretary of Transportation for administration of motor carrier safety programs, motor carrier safety research, and border enforcement activities. Provides funding for such period for: (1) the motor carrier safety assistance program (including for information systems); and (2) highway safety programs (including for highway safety research and development, occupant protection incentive grants, incentive grants for alcohol-impaired driving countermeasures, and the National Driver Register). Conditions the making of commercial motor vehicle and motor carrer safety grants to States from such amounts on a State's agreement that total State and local expenditures, exclusive of U.S. Government amounts, will be maintained at a level at least equal to the average level of those expenditures for the last two fiscal years before October 1, 2003.
Makes specified funds available for Coast Guard expenses for personnel and activities directly related to coordinating and carrying out the national recreational boating safety program. Prohibits the use of such funds available to the Secretary of Homeland Security for unauthorized purposes or to replace funding traditionally provided through general appropriations. Requires the Secretary to publish annually in the Federal Register a detailed accounting of the projects, programs, and activities funded. |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Student Financial Aid Simplification
Act''.
SEC. 2. FAFSA SIMPLIFICATION.
Section 483 of the Higher Education Act of 1965 (20 U.S.C. 1090) is
amended--
(1) in subsection (a)--
(A) in paragraph (1), by striking ``The Secretary''
and inserting ``Subject to subsection (i), the
Secretary''; and
(B) in paragraph (6), by striking ``The need'' and
inserting ``Subject to subsection (i), the need''; and
(2) by adding at the end the following new subsection:
``(i) FAFSA Simplification.--
``(1) In general.--Beginning academic year 2017-2018 and
notwithstanding subsection (a)(6) or any other provision of
this section, with respect to a student who is a taxpayer or a
dependent of a taxpayer and who does not meet the requirements
of subsection (b) or (c) of section 479, the need and
eligibility of such student for financial assistance under
parts A through E (other than subpart 4 of part A) may be
determined only by--
``(A) authorizing the Secretary to obtain from the
Internal Revenue Service income data, and other
taxpayer data needed to compute an expected family
contribution for the student, from two years prior to
the student's planned enrollment date; and
``(B) submitting to the Secretary the supplemental
information described in paragraph (3).
``(2) Authorization under the irc and distribution of
data.--Returns and return information (as defined in section
6103 of the Internal Revenue Code of 1986) may be obtained
under paragraph (1)(A) only to the extent authorized by section
6103(l)(23) of such Code, except that institutions of higher
education and States shall receive, without charge, such
information from the Secretary for the purposes of processing
loan applications and determining need and eligibility for
institutional and State financial aid awards.
``(3) Supplemental information.--Each student described in
paragraph (1) who is applying for financial assistance under
parts A through E (other than under subpart 4 of part A) shall
submit to the Secretary at such time and in such manner as
required by the Secretary, any information that is needed to
determine the student's need and eligibility for such financial
assistance or to administer the programs under this title, but
that is not available from the Internal Revenue Service to the
extent authorized by section 6103(l)(23) of the Internal
Revenue Code of 1986, including information with respect to the
student's--
``(A) citizenship or permanent residency status;
``(B) dependency status;
``(C) registration for selective service;
``(D) State and length of legal residence;
``(E) family members, including the total number
and the number in postsecondary education;
``(F) secondary school completion status;
``(G) completion of a first bachelor's degree;
``(H) email address; and
``(I) institution or institutions of higher
education in which the student is enrolled or to which
the student is applying for admission.
``(4) Regulations.--
``(A) In general.--The Secretary shall prescribe
such regulations as may be necessary to carry out this
subsection.
``(B) Inapplicability of rulemaking requirements.--
Sections 482(c) and 492 shall not apply to the
regulations required by this paragraph.''.
SEC. 3. AMENDMENTS TO INTERNAL REVENUE CODE OF 1986.
Section 6103(l) of the Internal Revenue Code of 1986 is amended by
adding at the end the following new paragraph:
``(23) Disclosure of return information to determine need
and eligibility of student for federal student financial aid.--
``(A) In general.--The Secretary may, upon written
request from the Secretary of Education, disclose to
officers and employees of the Department of Education
return information with respect to a taxpayer or a
dependent of a taxpayer who may be eligible for Federal
student financial aid and whose need and eligibility
for such aid is based in whole or in part on the
taxpayer's income or the income of the parents of the
dependent. Such return information shall be limited
to--
``(i) taxpayer identity information with
respect to such taxpayer;
``(ii) the filing status of such taxpayer;
``(iii) the adjusted gross income of such
taxpayer; and
``(iv) any other data of such taxpayer
necessary to determine the expected family
contribution (within the meaning of part F of
title IV of the Higher Education Act of 1965
(20 U.S.C. 1087kk et seq.)) of such taxpayer or
the dependent of such taxpayer, as applicable.
``(B) Restriction on use of disclosed
information.--Return information disclosed under
subparagraph (A) may be used by officers and employees
of the Department of Education only for the purposes
of, and to the extent necessary in, processing the
student loan application, and establishing need and
eligibility for Federal student financial aid, of a
taxpayer or a dependent of a taxpayer.
``(C) Federal student loans and grants.--For
purposes of this paragraph, the term `Federal student
financial aid' means financial assistance under parts A
through E (other than under subpart 4 of part A) of
title IV of the Higher Education Act of 1965 (20 U.S.C.
1070 et seq.).''. | Student Financial Aid Simplification Act This bill amends title IV (Student Assistance) of the Higher Education Act of 1965 to determine a student's financial need and federal financial aid eligibility by using tax return information, unless such student qualifies for the simplified needs test or a zero expected family contribution. It amends the Internal Revenue Code to authorize the Internal Revenue Service (IRS) to disclose certain tax return information to the Department of Education (ED). Students must submit to ED certain supplemental information not available from the IRS. The bill requires ED to provide such tax return information to states and institutions of higher education, without charge, for use processing loan applications and determining institutional and state financial aid awards. |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Supporting Emotional Learning Act''.
SEC. 2. FINDINGS.
The Congress finds as follows:
(1) A positive, healthy school community where children
thrive and grow, both intellectually and emotionally, takes
purposeful and thoughtful planning. Students who develop
personal strengths like grit, perseverance, concern for others,
and positive academic mindsets become important contributors to
their school and community. Schools have a responsibility to
nurture the intrapersonal and interpersonal skills students
need to navigate social situations and effectively and
respectfully communicate with a diverse group of people.
(2) In the United States, we have always placed an emphasis
on developing academically rigorous curriculum, but
unfortunately have not been as deliberate about imparting
children with important social and emotional life skills. There
needs to be a balance and integration between cognitive
learning and social emotional learning.
(3) While not a new concept, the term ``social and
emotional education'' has recently become an important focal
point for many researchers, administrators, and teachers. The
term ``social and emotional learning'' means the process
through which individuals acquire and effectively apply the
knowledge, attitudes, and skills necessary to understand and
manage emotions, the ability to set and achieve positive goals,
feel and show empathy for others, establish and maintain
positive relationships, and make responsible decisions.
(4) Research has shown that social and emotional learning
effectively boosts student academic success and fosters the
very skills that are being utilized in the workforce. Social
and emotional learning both increases protective factors for
helping children learn and thrive as well as reducing risks for
problems in both learning and behavior. These teachable skills
help children avoid risky behaviors such as aggression and
early drug and alcohol use and provide a springboard for being
a capable student, citizen, and worker.
(5) Continued research is necessary to discover best
practices and prepare educators to integrate social-emotional
skills into the curriculum and school culture. In addition, we
need to support well-designed theoretical models and
implementation supports in social and emotional learning.
Social and emotional learning should be included as a central
component of our education system. Federal law needs to include
language that prioritizes social and emotional learning for
educators.
SEC. 3. DUTIES OF THE NATIONAL CENTER FOR EDUCATION RESEARCH.
Section 133(a) of the Education Sciences Reform Act of 2002 (20
U.S.C. 9533(a)) is amended--
(1) in paragraph (10), by striking ``and'' at the end;
(2) in paragraph (11), by striking the period at the end
and inserting ``; and''; and
(3) by adding at the end the following:
``(11) carry out research initiatives regarding the impact
of social and emotional education.''.
SEC. 4. RESEARCH TOPICS OF THE COMMISSIONER FOR EDUCATION RESEARCH.
Section 133(c)(2) of the Education Sciences Reform Act of 2002 (20
U.S.C. 9533(c)(2)) is amended by adding at the end the following:
``(L) Social and emotional skills and habits.''.
SEC. 5. COMPREHENSIVE CENTERS.
Section 203(f)(1)(A)(ii) of the Education Sciences Reform Act of
2002 (20 U.S.C. 9602(f)(1)(A)(ii)) is amended--
(1) in subclause (II), by striking ``and'' at the end; and
(2) by adding at the end the following:
``(IV) imparting social and
emotional life learning (as defined in
section 200(24) of the Higher Education
Act of 1965 (20 U.S.C. 1021)); and''.
SEC. 6. SOCIAL AND EMOTIONAL LEARNING.
(a) Definitions.--Section 200 of the Higher Education Act of 1965
(20 U.S.C. 1021) is amended--
(1) in paragraph (13), by inserting at the end the
following: ``, except that such term includes a requirement
that highly qualified teachers have preparation in the
understanding, use, and development of social and emotional
learning programming''; and
(2) by adding at the end the following:
``(24) Social and emotional learning.--
``(A) In general.--The term `social and emotional
learning' means the processes through which students
acquire and effectively apply the following set of
interrelated competencies:
``(i) Self-awareness and self-management
skills to achieve academic and life success.
``(ii) Social awareness and relationship
skills to establish and maintain positive
relationships.
``(iii) Responsible decisionmaking skills
and behavior in personal, school, and community
contexts.
``(B) Self-awareness.--The term `self-awareness'
means an individual's ability to accurately recognize--
``(i) the individual's own feelings and
thoughts; and
``(ii) the influence of such feelings and
thoughts on the individual's behaviors.
``(C) Self-management.--The term `self-management'
means an individual's ability to--
``(i) regulate the individual's own
emotions, cognitions, and behaviors effectively
in different situations; and
``(ii) set and work toward personal and
academic goals.
``(D) Social awareness.--The term `social
awareness' means an individual's ability to--
``(i) take the perspective of and empathize
with individuals from diverse backgrounds and
cultures; and
``(ii) recognize family, school, and
community resources and supports.
``(E) Relationship skill.--The term `relationship
skill' means an individual's ability to establish and
maintain healthy and rewarding relationships with
individuals from diverse backgrounds and cultures
through communicating clearly, listening actively,
cooperating, negotiating conflict constructively, and
seeking and offering help when needed.
``(F) Responsible decisionmaking skills and
behavior.--The term `responsible decisionmaking skills
and behavior' means an individual's ability to make
constructive and respectful choices about personal
behavior and social interactions, based on
consideration of ethical standards, safety concerns,
the realistic evaluation of consequences that stem from
actions, and the well-being of self and others.
``(25) Social and emotional learning programming.--The term
`social and emotional learning programming' refers to
instruction, activities, and best practice initiatives that--
``(A) integrate social and emotional learning with
academic achievement;
``(B) provide systematic instruction whereby social
and emotional skills are taught, modeled, practiced,
and applied so that students use them as part of their
daily behavior;
``(C) teach students to apply social and emotional
skills to prevent specific problem behaviors such as
substance use, violence, bullying, and school failure,
and to promote positive behaviors in class, school, and
community activities; and
``(D) establish safe and caring learning
environments that foster student participation,
engagement, and connection to learning and school.''.
(b) Teacher Quality Partnership Grants.--Section 202 of the Higher
Education Act of 1965 (20 U.S.C. 1022a) is amended--
(1) in subsection (b)--
(A) by striking the period at the end of paragraph
(7)(D) and inserting ``; and''; and
(B) by adding at the end the following:
``(8) a description of how the eligible partnership will
prepare prospective and new teachers and principals, if
applicable, to understand, use, and develop social and
emotional learning programming.'';
(2) in subsection (e)(1)(C)--
(A) by striking ``and'' at the end of clause (iii);
(B) by striking the period at the end of clause
(iv) and inserting ``; and''; and
(C) by adding at the end the following:
``(v) preparation in understanding, using,
and developing social and emotional learning
programming.''; and
(3) in subsection (f)(1)(C)--
(A) by striking ``and'' at the end of clause (ii);
(B) by striking the period at the end of clause
(iii) and inserting ``; and''; and
(C) by adding at the end the following:
``(iv) preparation in understanding, using,
and developing social and emotional learning
programming.''.
(c) Augustus Hawkins Centers of Excellence.--Section 242(b)(1)(B)
of the Higher Education Act of 1965 (20 U.S.C. 1033a(b)(1)(B)) is
amended--
(1) in clause (i), by striking ``and'' at the end;
(2) by striking the period at the end of clause (ii) and
inserting ``; and''; and
(3) by adding at the end the following:
``(iii) promoting the understanding, use,
and development of social and emotional
learning programming.''.
(d) Teach To Reach Grants.--Section 251(c)(1)(B) of the Higher
Education Act of 1965 (20 U.S.C. 1034(c)(1)(B)) is amended--
(1) by striking ``and'' at the end of clause (iv); and
(2) by adding at the end the following:
``(vi) understanding, using, and developing
social and emotional learning programming;
and''. | Supporting Emotional Learning Act Amends the Education Sciences Reform Act of 2002 to require: the National Center for Education Research to carry out research regarding the impact of social and emotional education; the Commissioner for Education Research to support research into social and emotional skills and habits; and comprehensive centers to provide training, professional development, and technical assistance regarding the use of scientifically valid teaching methods and assessment tools in imparting social and emotional life learning. Amends the Higher Education Act of 1965 to require highly qualified teachers to have preparation in the understanding, use, and development of social and emotional learning programming. Defines "social and emotional learning" as the processes through which students acquire and effectively apply: self-awareness and self-management skills to achieve academic and life success; social-awareness and relationship skills to establish and maintain positive relationships; and responsible decisionmaking skills and behavior in personal, school, and community contexts. Requires Teacher Quality Partnership grants to be used in preparing prospective and new teachers and principals to understand, use, and develop social and emotional learning programming. (Teacher Quality Partnership grants are provided to partnerships between high-need local educational agencies [LEAs], their high-need schools, and institutions of higher education [IHEs].) Requires centers of excellence to design teacher training programs that promote the understanding, use, and development of social and emotional learning programming. (Centers of excellence are minority-serving IHEs or partnerships between such IHEs and other IHEs that are awarded grants to ensure that current and future teachers are highly qualified.) Requires Teach to Reach grants to be used to train general education teacher candidates to understand, use, and develop social and emotional learning programming. (Teach to Reach grants are provided to partnerships between IHEs and high-need LEAs to more effectively prepare general education teacher candidates to instruct disabled students in general education classrooms). |
drug - induced liver injury ( dili ) is defined as a liver injury due to xenobiotics , herbs , or medications that leads to either liver dysfunction or abnormal liver serology , in the setting of no other identifiable cause . unlike idiosyncratic drug induced liver injury ( idili ) , dili seems to be dose - dependent , predictable , and reproducible .
dili has been associated with more than 1,000 medications and is the most common cause of acute liver failure in the united states , accounting for approximately 50% of fulminant cases.15,6 while retrospective studies have shown acetaminophen to be the most common cause of dili , studies in liver transplant patients have demonstrated antibiotics and immunosuppressive agents , such as tacrolimus and azathioprine , as the top causes.7,8 bjornsson et al . performed a prospective study and found that amoxicillin - clavulanate was the most commonly implicated antibiotic .
the incidence was approximately 19 cases per 100,000.9 in addition to the typical suspects stated above , herbal and dietary supplements have been a rising cause of dili , now accounting for up to 9% of all cases.10 in fact , one study based in china , which spanned eight years , found that nearly half of all cases were secondary to medicinal herbs.11 while dili is most commonly due to only one drug , a prospective study demonstrated that nearly 10% of cases were attributable to more than one medication.9
dili has several clinical manifestations ranging from asymptomatic elevations in liver enzymes to fulminant liver failure .
hepatic , or cytochrome p450 , metabolism of a drug has been strongly linked to dili , and one study demonstrated that those medications that rely on more than 50% hepatic metabolism have a greater risk for alanine transferase ( alt ) elevation , liver failure , and mortality.12 other proposed mechanisms for dili include autoimmunity and hypersensitivity.2,13 despite the possible mechanisms , treatment options all follow the same principles .
the most important , and first , step is early diagnosis followed by discontinuation of the offending agent.2
the most common presenting symptom in most cases of dili is jaundice , although many cases are asymptomatic or have elevated enzymes incidentally detected.11 however , dili can present as cholestatic , hepatocellular , and mixed ; and proper diagnosis will direct the treatment of a particular case .
cholestatic liver injury is defined by predominant elevations of alkaline phosphatase ( alp ) , whereas hepatocellular liver injury is defined as predominant elevations of aspartate transferase ( ast ) and alt , and mixed has elevations in both alp and transaminases.14 it is important to note that alt is liver - specific , whereas elevations in ast may be associated with damage to skeletal or cardiac muscle or in conditions such as myocardial infarction and rhabdomyolysis .
hepatocellular injury remains the most common presentation and is correlated with a worse outcome.15,16
table 1 provides specific definitions for both cholestatic and hepatocellular injury , which may aid in the identification of the patient 's clinical diagnosis .
once liver injury has been established , the next step is to determine the underlying cause .
risk factors for dili have been difficult to determine with many studies because of conflicting results in regard to sex and age - related occurrences .
however , a recent study found that older age and female sex was associated with a cholestatic type injury , while younger age and male sex was associated with hepatocellular type injury .
genetic polymorphisms have been consistently found to be a risk factor for dili but are not typically tested for in patients prior to receiving a medication.17,18 finally , liver transplant patients where the reason for transplant was primary sclerosing cholangitis are at greater risk for developing dili.8 chronic liver disease is a risk factor but only for certain medications , including methotrexate , isoniazid , and hiv antiretroviral therapy.2 when diagnosing dili , several established criteria can be used , none of which is considered to be a gold standard .
hy 's law is specific but not sensitive , whereas the roussel uclaf causality assessment method ( rucam ) is more sensitive but more difficult to administer in its truest form as it is complicated and requires rechallenging patients once they have recovered.1921 one modification is the digestive disease week - japan ( ddw - j ) scale , which includes lymphocyte stimulation testing , although this test has not been validated.22 yet another modification is the clinical diagnostic scale ( cds ) or maria and victorino ( m&v ) scale , which is more simple to administer but less predictive in patients who have had a prolonged period of time between drug use and development of symptoms or in those patients who have developed chronic liver injury.23,24 when examining these scales , common features , which make them specific and sensitive tests , include temporal relationship , exclusion of other causes , and prior reports of hepatoxicity of the suspected medication . while specific criteria may be used , at a minimum the above three commonalities should be investigated . for reference ,
wang et al found in china that the majority of cases occurred between 5 and 90 days of the initiation of the drug.11 as an aid for the clinician , table 2 provides medications and their typical liver injury presentation .
once a specific drug has been identified as the cause of dili , it must be discontinued.2 following withdrawal of the suspected agent , therapy is largely supportive with a few notable exceptions for acetaminophen and amanita mushroom poisoning .
all patients ' laboratory values , including ast , alt , alp , bilirubin , and international normalized ratio ( inr ) and mental statuses should be monitored for changes .
it is important to note that measuring only ast and alt is insufficient when monitoring liver function in dili .
damage to hepatocytes causes elevation of ast and alt levels , and once sufficient damage has occurred , there are less hepatocytes and ast and alt levels begin to decrease.14 therefore , bilirubin and inr must also be monitored . with discontinuation of the drug ,
most cases resolve without further sequelae , with one prospective study reporting a median duration from diagnosis to normalization of laboratory values of 64 days.9
lee et al .
performed an eight year prospective , double - blind , placebo control trial of n - acetylcysteine ( nac ) for patients with acute liver failure not secondary to acetaminophen overdose .
while overall survival was similar in the populations ( 70% vs. 66% ) , transplant - free survival was significantly better for those who received nac ( 40% vs. 27%).25 at this time , nac therapy can and should be considered for patients who are presenting with acute liver failure . in addition , a small uncontrolled study performed by wree et al . compared steroid pulse therapy with steroid step down therapy , both in combination with ursodeoxycholic acid , in the treatment of drug - induced liver injury , including patients with hepatocellular and/or cholestatic injury .
both therapies demonstrated a decrease in time to normalization of bilirubin , ast , and alt values.26 however , since this was an uncontrolled study , it is uncertain if the observed improvement in their patient population actually reflected the natural history of dili .
treatment for acetaminophen toxicity largely consists of nac therapy . studies have conflicted between whether oral or intravenous ( iv ) therapy should be given .
yarema et al . compared iv to oral administration and found that hepatoxicity occurred less often in patients who received iv therapy within 12 hours of ingestion.27 however , a recent study performed using a simulation system demonstrated that for those patients presenting within 24 hours of acetaminophen ingestion , the oral protocol is superior to the 21-hour intravenous protocol in persevering hepatocytes .
these authors argued that yarema 's study contained two differing treatment groups.28 regardless , nac therapy should be started if there is an elevation in ast , a detectable acetaminophen level , or if the level is above the treatment line on the rumack - matthew nomogram.29 a computer simulation suggested that international normalized ratio ( inr ) did not undertreat patients but did lead to overtreatment , whereas treating until alt peaked did not undertreat and rarely overtreated patients.28 current recommendations are to treat according to the protocol and to recheck ast and the acetaminophen level . at this point , ast should be less than 100 iu / l and acetaminophen level should be less than 10 mcg / ml . if not , therapy should be continued using the normalization of inr as a marker of resolution.30
amanita mushroom ingestion can lead to liver injury via the amatoxin , which inhibits rna polymerase ii and leads to hepatocyte necrosis .
this is followed by symptomatic improvement but an elevation in ast and alt followed by the development of jaundice .
since the hepatic phase is preceded by a gastrointestinal phase where dehydration and metabolic derangements may have developed , it is important to treat any dehydration and electrolyte abnormalities.31 while it has no proven efficacy for long - term survival , repeated activated charcoal administration is often recommended , which will prevent reabsorption of the amatoxin . while amatoxin may cause metabolic acidosis on its own , activated charcoal , which contains propylene glycol , can also cause a high anion gap metabolic acidosis . while clinicians should be aware of this potential complication , it should not preclude treatment with activated charcoal.32 silibinin is universally accepted as a treatment modality for amatoxin poisoning because it inhibits the transfer of amanitin into hepatocytes .
it should be administered within 48 hours of mushroom ingestion . the current recommended dose is 20 to 50 mg / kg / day iv , which should be continued for 4896 hours .
the recommended dose is 1,000,000 iu / kg for first day and 500,000 iu / kg for next two days via continuous iv administration .
finally , if started early , the molecular adsorbent recirculating system may be considered as it does improve liver function , although no specific studies have been done with amanita mushroom poisoning.31
patients who present with fever , rash , and eosinophilia should be considered for a diagnosis of drug - induced autoimmune hepatitis .
if the dili is severe , corticosteroid therapy should be considered as studies have demonstrated normalization of biochemical tests within six months.33
finally , patients who present with a cholestatic picture may complain of intense pruritus .
treatment options for these patients include emollients , hydroxyzine , diphenhydramine , bile acid resins , and rifampicin.34
extracorporeal systems have progressed through advances in genetically produced cell lines , stem cell - derived functional hepatocytes , immortalized human hepatocytes as well as improved techniques and methods for preserving the hepatocytes .
the system , composed of a hollow - fiber cartridge lined with porcine hepatocytes , was used in a multi - center trial showing survival benefit to those treated.35 advances in bioartificial livers continue with current trials being conducted by vital therapies and hepa wash gmbh ( clinicaltrials.gov ) .
these devices provide the potential for significant benefit to patients with dili , subacute fulminate failure , and fulminate failure ; and we are encouraged for the use of this technology in the future treatment of these patients .
the king 's college criteria have been developed for both paracetamol and non - paracetamol causes in order to determine when a patient should be initially referred for transplantation .
the criteria include a prothrombin time ( pt ) over 100 seconds or at least three of the following : pt over 50 seconds , bilirubin > 300 micromol / liter , age below 10 or over 40 , an interval between jaundice and encephalopathy greater than seven days , or drug toxicity.37 other criteria that may be used include clinchy 's criteria and escudie 's criteria . patients with fulminant liver failure , defined as the presentation of hepatic encephalopathy within eight weeks of the development of symptoms related to liver disease , should be referred for transplant . in the united states , according to united network for organ sharing ( unos ) , a status 1a listing may be obtained if the patient has a life expectancy of seven days or less , does not have a pre - existing liver disease , and is in the intensive care unit requiring either ventilator assistance or dialysis or with an inr greater than two.38 however , it is important to keep in mind the contraindications for transplant , which include significant comorbidities and active malignancy .
each patient should be considered on a case - by - case basis , and the guidelines should be consulted when considering a patient for transplant .
although it has a varied presentation and multiple possible drug causes , treatment for all cases requires discontinuation of the offending agent .
if a patient has ingested acetaminophen or amanita mushrooms , appropriate therapy should be administered .
all patients can now be considered for nac therapy and should be monitored for normalization of biochemical tests . | drug - induced liver injury ( dili ) has been linked to more than 1,000 medications and remains the most common cause of acute liver failure in the united states . here , we review the most current literature regarding treatment and make recommendations for the management of this relatively common disease .
since treatment of dili remains largely elusive , recent studies have attempted to define new management strategies for these difficult patients . early diagnosis and withdrawal of the suspected medication
is the mainstay of treatment of dili . for acetaminophen and amanita mushroom poisoning ,
there are specific therapies in use .
finally , there are other possible management modalities for dili , including corticosteroids and ursodeoxycholic acid . |
Associated Press
Yes, it was that time again, folks. Jobs Friday, when for one ever-so-brief moment the interests of Wall Street, Washington and Main Street are all aligned on one thing: jobs.
The Bureau of Labor Statistics reported that U.S. economy added 257,000 jobs in January, ahead of the consensus expectation of 237,000. Revisions showed that employment gains in the last two months of 2014 included 147,000 more jobs than previous estimated.
Here at MoneyBeat HQ, we crunched the numbers, tracked the markets and compiled the commentary before and after the data crosses the wires. Now that we’re done, feel free to continue the conversation in the comments section. And while you’re here, why don’t you sign up to follow us on Twitter. ||||| WASHINGTON (AP) — U.S. employers added a vigorous 257,000 jobs in January, and wages jumped by the most in six years — evidence that the U.S. job market is accelerating closer to full health.
In this Friday, Jan. 23, 2015 photo, job applicant Rafael Ferrer, 49, left, shakes hands with a representative of the Hilton Bentley Miami Beach hotel during a job fair at the Hospitality Institute, Friday,... (Associated Press)
The surprisingly robust report the Labor Department issued Friday also showed that hiring was far stronger in November and December than previously thought. Employers added 414,000 jobs in November — the most in 17 years. Job growth in December was also revised sharply higher, to 329,000, from 252,000.
Average hourly wages soared 12 cents in December to $24.75, the biggest gain since September 2008. In the past year, hourly pay has increased 2.2 percent. That is ahead of inflation, which rose just 0.7 percent in 2014.
The sharp drop in gas prices in the past year has held down inflation and boosted Americans' spending power. Still, wages typically rise at a roughly 3.5 percent pace in a fully healthy economy.
The unemployment rate in January rose to 5.7 percent from 5.6 percent. But that occurred for a good reason: More Americans began looking for jobs, though not all of them found work. Their job hunting suggests that they are more confident about their prospects.
Strong hiring pushes up wages as employers compete for fewer workers. Job gains have now averaged 336,000 a month for the past three months, the best three-month pace in 17 years. Just a year ago, the three-month average was only 197,000.
The Federal Reserve is closely monitoring wages and other job market data as it considers when to begin raising the short-term interest rate it controls from a record low near zero. The Fed has kept rates at record lows for more than six years to help stimulate growth. Most economists think the central bank will start boosting rates as early as June.
Steady economic growth has encouraged companies to keep hiring. The economy expanded at a 4.8 percent annual rate during spring and summer, the fastest six-month pace in a decade, before slowing to a still-decent 2.6 percent pace in the final three months of 2014.
There are now 3.2 million more Americans earning paychecks than there were 12 months ago. That lifts consumer spending, which drives about 70 percent of economic growth.
More hiring, along with sharply lower gasoline prices, has boosted Americans' confidence and spending power. Consumer confidence jumped in January to its highest level in a decade, according to a survey by the University of Michigan. And Americans increased their spending during the final three months of last year at the fastest pace in nearly nine years. | – The US economy added 257,000 jobs last month, a full 20,000 more than economists had expected today's jobs report to show, the Wall Street Journal reports. The unemployment rate ticked up from 5.6% to 5.7%, but as the AP explains, that's partially because more Americans started looking for work, showing confidence in the economy. As Kevin Kingsbury writes for the Journal, "In this case, today’s increase is actually a good sign." But while the labor force participation rate did inch up to 62.9%, last month's 62.7% was a "multi-decade low." Paul Vigna's take: "So, that’s at least movement in the right direction, but it’s not much movement. ... It’s hard to get growth really going with so many people out of the work force." December's new jobs number was revised significantly upward from 252,000 to 329,000, and November's number was revised all the way up to 414,000—the highest total in 17 years. Plus, average hourly wages rose 12 cents to $24.75, the biggest gain since September 2008. In the past year, hourly pay has increased 2.2%. That is ahead of inflation, which rose just 0.7% in 2014. All in all: The Bureau of Labor Statistics says 2014, in which average monthly job gains were 258,000, was the best year since 1999 for jobs growth. |
postoperative morbidity affects the overall survival , postoperative mortality , length of hospital stay , and cost of treatment involved in every major surgical procedure . in gastric cancer surgery
postoperative morbidity remains high and even if the incidence of gastric cancer declines in the future this is likely to remain a problem .
it is therefore crucial for both the patient and surgeon to have a reliable risk assessment model for each major surgical procedure .
for this reason the number of scoring systems involved in preoperative risk assessment has become increasingly tailored to specific groups of patients [ 2 , 3 ] .
scoring systems predict risk and lead to the implementation of both prophylactic measures and appropriate perioperative treatment plans . in the case of gastric cancer ,
primarily a surgical disease , the group of patients disqualified from surgery due to unacceptably high preoperative risk is marginal .
therefore , a need has arisen for additional markers or measures that reflect operative injury .
acute phase proteins ( apps ) are defined as those proteins whose serum concentrations increase or decrease by at least 25% during inflammatory or post - injury states .
changes in levels of apps result from the effects of inflammatory mediators , mainly cytokines .
some of the major cytokines relevant to the acute phase response are interleukin ( il)-6 , il-1 beta , tumor necrosis factor - alpha ( tnf- ) and interferon gamma .
these proteins stimulate app production , with il-6 being the major inducer of most apps .
this family of cytokines also suppresses the synthesis of albumin by the liver . on the other hand , some cytokines ( il-10 and il-4 ) suppress the inflammatory reaction .
in addition to changes in the levels of apps , a number of behavioral , physiologic , biochemical , and nutritional changes are induced by inflammation - associated cytokines .
these include : fever ; neuroendocrine system effects , such as increased production of corticotropin - releasing hormone ; and anemia of chronic disease .
cytokines , especially il-6 , are also known to correlate with operative stress and in some surgical procedures cytokines have been shown to be reliable markers of postoperative morbidity .
the aim of this study was to investigate whether high serum levels of il-6 in the early postoperative period may be a prognostic factor of postoperative morbidity .
a group of 99 consecutive patients with resectable gastric cancer were enrolled in the study between n march 2005 and september 2006 .
this study was a cohort study in which gastric cancer patients were followed up for postoperative complications .
for the purpose of the study two groups of patients were created in the post - hoc analysis .
those whose serum il-6 level was over the 90th percentile in the whole study group on the 1st postoperative day ( pod ) were defined as the high il-6 level group , and those whose level was below the value mentioned were defined as the low il-6 level group .
the cutoff level was arbitrally set because there are no data in the literature that indicate specific cutoff values or allow the creation of high level or low level groups in the postoperative period .
there were 27 women and 72 men in our cohort , and the mean age was 62.9 years ( sd 11.2 ) , with ages ranging between 33 and 86 years .
all patients were treated with standard postoperative care , including enteral nutrition , antimicrobial prophylaxis for up to 48 h post - surgery , and low - molecular - weight heparin ( lmwh ) .
all complications associated with each patient were recorded daily , up to the day of discharge , and thereafter weekly for up to 14 days .
tumor staging was assessed according to the international union against cancer ( uicc ) tnm classification , 7th edition .
the details of clinicopathological status are summarized in table 1.table 1patients characteristicsn = 99gender ( n , % ) women27 ( 27.3% ) men72 ( 72.7%)age ( years ) mean ( sd)62.9 ( 11.2 ) min max3386stage ( n , % ) i8 ( 8.1% ) ii22 ( 22.2% ) iii23 ( 23.2% ) iv46 ( 46.5%)n = 97lauren classification ( n , % ) intestinal ( 1)36 ( 37.1% ) diffuse ( 2)60 ( 60.6% ) not classified1 ( 1.0%)type of surgery ( n , % ) subtotal resection22 ( 22.2% ) total resection77 ( 77.8%)tumor location ( n , % ) cardia27 ( 27.3% ) other locations72 ( 72.7%)resection radicality ( n , % ) r046 ( 46.5% ) r142 ( 42.4% ) r211 ( 11.1% ) patients characteristics standard lymphadenectomy for r0 and r1 resections was d2 . in all cases of palliative resections
nutritional status was assessed . as the measures of malnutrition , total albumin level ( cutoff < 3.5 g / dl ) , lymphocyte count ( cutoff < 1500/mm ) , and weight loss greater than 10% of body weight during 6 months were adopted .
cardiovascular diseases were observed in 49 patients , respiratory diseases in 7 patients , diabetes mellitus in 8 patients , and other chronic comorbidities in 10 patients .
the blood was centrifuged and serum samples were stored at 55c . for the il-6 assay
the following monoclonal antibodies were used : il-6 clone mq2 - 13a5 ( capture ) and mq2 - 39c3 ( detection ) ; antibodies were diluted in 0.1 mol phosphate buffer , ph 9.0 , and placed on a 96-well microplate ( nunc maxisorb , roskilde , denmark ) according to the manufacturer s instructions .
the results were read using an enzyme - linked immunosorbent assay ( elisa ) microplate reader ( universal microplate reader ; bio - tek instruments , winooski , vt , usa ) at the wavelength of 490/630 nm .
the postoperative course was monitored , and all adverse events were recorded and analyzed . the complication rate was based upon clinical assessment , imaging studies , and microbiological examination .
complications were stratified into five groups : infective complications ( pneumonia , urinary tract infections , catheter - related infections , superficial wound infections)surgical complications ( anastomotic / duodenal stump leakage , intraabdominal bleeding , pancreatic fistula , wound dehiscence , intestinal obstruction , delayed wound healing)respiratory complications ( pulmonary embolism and respiratory insufficiency , not including pneumonia)cardio - circulatory complicationsother complications ( gastrointestinal [ gi ] bleeding , transient pyrexia with negative bacterial cultures and without clinical signs of infection ) infective complications ( pneumonia , urinary tract infections , catheter - related infections , superficial wound infections ) surgical complications ( anastomotic / duodenal stump leakage , intraabdominal bleeding , pancreatic fistula , wound dehiscence , intestinal obstruction , delayed wound healing ) respiratory complications ( pulmonary embolism and respiratory insufficiency , not including pneumonia ) cardio - circulatory complications other complications ( gastrointestinal [ gi ] bleeding , transient pyrexia with negative bacterial cultures and without clinical signs of infection ) the proportion of patients without complications was presented using kaplan meier curves and the difference between curves was tested using the log rank test . to define patients with high
for assessment of the risk of complications the cox proportional hazard model was used . for multivariate analysis ,
the following covariates were used : age ( 50 , 5160 , 6170 , > 70 years ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , resection radicality , nutritional status , and additionally : diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , and diagnosis of any other disease ( yes / no ) .
statistical analysis was performed using the stata v.8 ( statacorplp , college station , tx , usa ) software package .
blood samples were collected 1620 h post closure of the wound . the blood was centrifuged and serum samples were stored at 55c . for the il-6 assay the following monoclonal antibodies
were used : il-6 clone mq2 - 13a5 ( capture ) and mq2 - 39c3 ( detection ) ; antibodies were diluted in 0.1 mol phosphate buffer , ph 9.0 , and placed on a 96-well microplate ( nunc maxisorb , roskilde , denmark ) according to the manufacturer s instructions .
the results were read using an enzyme - linked immunosorbent assay ( elisa ) microplate reader ( universal microplate reader ; bio - tek instruments , winooski , vt , usa ) at the wavelength of 490/630 nm .
the postoperative course was monitored , and all adverse events were recorded and analyzed . the complication rate was based upon clinical assessment , imaging studies , and microbiological examination .
complications were stratified into five groups : infective complications ( pneumonia , urinary tract infections , catheter - related infections , superficial wound infections)surgical complications ( anastomotic / duodenal stump leakage , intraabdominal bleeding , pancreatic fistula , wound dehiscence , intestinal obstruction , delayed wound healing)respiratory complications ( pulmonary embolism and respiratory insufficiency , not including pneumonia)cardio - circulatory complicationsother complications ( gastrointestinal [ gi ] bleeding , transient pyrexia with negative bacterial cultures and without clinical signs of infection ) infective complications ( pneumonia , urinary tract infections , catheter - related infections , superficial wound infections ) surgical complications ( anastomotic / duodenal stump leakage , intraabdominal bleeding , pancreatic fistula , wound dehiscence , intestinal obstruction , delayed wound healing ) respiratory complications ( pulmonary embolism and respiratory insufficiency , not including pneumonia ) cardio - circulatory complications other complications ( gastrointestinal [ gi ] bleeding , transient pyrexia with negative bacterial cultures and without clinical signs of infection )
the proportion of patients without complications was presented using kaplan meier curves and the difference between curves was tested using the log rank test . to define patients with high
for assessment of the risk of complications the cox proportional hazard model was used . for multivariate analysis ,
the following covariates were used : age ( 50 , 5160 , 6170 , > 70 years ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , resection radicality , nutritional status , and additionally : diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , and diagnosis of any other disease ( yes / no ) .
statistical analysis was performed using the stata v.8 ( statacorplp , college station , tx , usa ) software package .
the number of events and the type of complications were recorded for each patient . because one patient could have more than one complication ,
the sum of complications ( sum of events ) exceeded the number of patients with complications .
complications were observed in 28 of the 99 patients ( 28.3% ) and the observed sum of events was 68 ( table 2).table 2types of complicationscomplication typen ( % ) infective24 ( 24.2)pneumonia20 ( 20.2)surgical9 ( 9.1)respiratory ( without pneumonia)5 ( 5.1)cardio - circulatory4 ( 4.0)other6 ( 6.1 ) types of complications the most frequent group of complications were infections , diagnosed in 24.2% of the patients . in this group
all of these patients had been diagnosed with hap on pods four to seven and had no major surgical complications
. the 1st pod serum level of il-6 was analyzed as it was the earliest postoperative measure available , reflecting not only preoperative factors but also operative injury . to assess the predictive value of il-6 serum levels on the 1st pod a cutoff level of 288.7 pg / ml ( the equivalent of the 90th percentile ) was set .
overall complications , including infective complications , were analyzed 14 days post - surgery .
the proportion of patients without complications was significantly higher in patients with il-6 levels below the cutoff value ( p = 0.035 ) , and the results were statistically significant ( fig .
il6 interleukin 6 , pod postoperative day cumulative proportion of patients without complications within 14 days post - surgery .
il6 interleukin 6 , pod postoperative day the hazard ratio ( hr ) of complication as an event assessed in the univariate cox proportional hazard model was significantly higher in patients with
low il-6 levels ( hr = 2.40 , 95% confidence interval [ ci ] 1.055.48)table 3 . the multivariate analysis produced similar results ( hr = 2.79 , 95% ci 1.017.76 ) and if the presence of the diagnosis of other chronic disease was taken into account the risk estimation was even higher ( table 3).table 3risk of overall complicationsil-6person - day ( observation)no . of events / no . of patientsrisk of complications ( hr)95% cipoverall complications1169 278.88 pg / ml19/83 ( 22.9%)1 > 278.88
pg / ml8/16 ( 50.0%)2.401.055.480.038overall complications1046 278.88 pg / ml16/74 ( 21.6%)1 > 278.88 pg / ml7/14 ( 50.0%)2.791.017.760.049overall complications1046 278.88 pg / ml16/74 ( 21.6%)1 > 278.88 pg / ml7/14 ( 50.0%)3.081.078.880.038overall complications1046 278.88 pg / ml16/74 ( 21.6%)1 > 278.88 pg / ml7/14 ( 50.0%)3.571.1511.100.028il-6 interleukin 6 , hr hazard ratio , ci confidence intervalunivariate cox proportional hazard modelmultivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months)multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , and diagnosis of any other disease ( yes / no)multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) ,
diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , diagnosis of any other disease ( yes / no ) ,
and resection radicality ( r0 , r1 , r2 ) risk of overall complications il-6 interleukin 6 , hr hazard ratio , ci confidence interval univariate cox proportional hazard model multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) ,
and diagnosis of any other disease ( yes / no ) multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , diagnosis of any other disease ( yes / no ) , and resection radicality ( r0 , r1 , r2 ) il-6 on the 1st pod was also analyzed as a potential predictor of infective complications .
the analysis of kaplan meier curves for the proportion of patients without infective complications over 14 postoperative days revealed a trend similar to that seen with overall complications ( fig . 2 ) .
moreover , these findings were confirmed by the univariate and multivariate cox proportional hazard models ( table 4).fig .
2cumulative proportion of patients without infective complications within 14 days post - surgerytable 4risk of infective complicationsil-6person - day ( observation)no . of events / no . of patientsrisk of complications ( hr)95% cipinfective complications1217 278.88 pg / ml16/83 ( 19.3%)1 > 278.88 pg / ml7/16 ( 43.8%)2.511.036.110.042infective complications1076 278.88 pg / ml14/74 ( 18.9%)1 > 278.88 pg / ml7/14 ( 50.0%)3.071.118.430.030infective complications1076 278.88 pg / ml14/74 ( 18.9%)1 > 278.88 pg / ml7/14 ( 50.0%)3.611.2310.600.020infective complications1076 278.88 pg / ml14/74 ( 18.9%)1 > 278.88 pg / ml7/14 ( 50.0%)4.351.3613.970.013univariate cox proportional hazard modelmultivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months)multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ) , total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) ,
diagnosis of diabetes ( yes / no ) , and diagnosis of any other disease ( yes / no)multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , diagnosis of any other disease ( yes / no ) , and resection radicality ( r0 , r1 , r2 ) cumulative proportion of patients without infective complications within 14 days post - surgery risk of infective complications univariate cox proportional hazard model multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ) , total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , and diagnosis of any other disease ( yes / no ) multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) ,
diagnosis of diabetes ( yes / no ) , diagnosis of any other disease ( yes / no ) , and resection radicality ( r0 , r1 , r2 ) to avoid the confounding effect of surgical radicality , another model , with classification r ( 0 , 1 , 2 ) as one of possible confounding variables , was performed . risk estimates for overall complications and infective complications were similar to those observed in the previous analyses ( tables 3 , 4 ) .
the 1st pod serum level of il-6 was analyzed as it was the earliest postoperative measure available , reflecting not only preoperative factors but also operative injury . to assess the predictive value of il-6 serum levels on the 1st pod a cutoff level of 288.7 pg / ml ( the equivalent of the 90th percentile ) was set .
overall complications , including infective complications , were analyzed 14 days post - surgery .
the proportion of patients without complications was significantly higher in patients with il-6 levels below the cutoff value ( p = 0.035 ) , and the results were statistically significant ( fig .
il6 interleukin 6 , pod postoperative day cumulative proportion of patients without complications within 14 days post - surgery .
il6 interleukin 6 , pod postoperative day the hazard ratio ( hr ) of complication as an event assessed in the univariate cox proportional hazard model was significantly higher in patients with
low il-6 levels ( hr = 2.40 , 95% confidence interval [ ci ] 1.055.48)table 3 .
the multivariate analysis produced similar results ( hr = 2.79 , 95% ci 1.017.76 ) and if the presence of the diagnosis of other chronic disease was taken into account the risk estimation was even higher ( table 3).table 3risk of overall complicationsil-6person - day ( observation)no . of events / no . of patientsrisk of complications ( hr)95% cipoverall complications1169 278.88 pg / ml19/83 ( 22.9%)1 > 278.88 pg / ml8/16 ( 50.0%)2.401.055.480.038overall complications1046 278.88 pg / ml16/74 ( 21.6%)1 > 278.88 pg / ml7/14 ( 50.0%)2.791.017.760.049overall complications1046 278.88 pg / ml16/74 ( 21.6%)1 > 278.88
pg / ml16/74 ( 21.6%)1 > 278.88 pg / ml7/14 ( 50.0%)3.571.1511.100.028il-6 interleukin 6 , hr hazard ratio , ci confidence intervalunivariate cox proportional hazard modelmultivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months)multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i
iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , and diagnosis of any other disease ( yes / no)multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , diagnosis of any other disease ( yes / no ) , and resection radicality ( r0 , r1 , r2 ) risk of overall complications il-6 interleukin 6 , hr hazard ratio , ci confidence interval univariate cox proportional hazard model multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , and diagnosis of any other disease ( yes / no ) multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , diagnosis of any other disease ( yes / no ) , and resection radicality ( r0 , r1 , r2 ) il-6 on the 1st pod was also analyzed as a potential predictor of infective complications .
the analysis of kaplan meier curves for the proportion of patients without infective complications over 14 postoperative days revealed a trend similar to that seen with overall complications ( fig . 2 ) .
moreover , these findings were confirmed by the univariate and multivariate cox proportional hazard models ( table 4).fig .
2cumulative proportion of patients without infective complications within 14 days post - surgerytable 4risk of infective complicationsil-6person - day ( observation)no . of events / no .
278.88 pg / ml16/83 ( 19.3%)1 > 278.88 pg / ml7/16 ( 43.8%)2.511.036.110.042infective complications1076 278.88 pg / ml14/74 ( 18.9%)1 > 278.88 pg / ml7/14 ( 50.0%)3.071.118.430.030infective complications1076 278.88 pg / ml14/74 ( 18.9%)1 > 278.88 pg / ml7/14 ( 50.0%)3.611.2310.600.020infective complications1076 278.88 pg / ml14/74 ( 18.9%)1 > 278.88 pg / ml7/14 ( 50.0%)4.351.3613.970.013univariate cox proportional hazard modelmultivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months)multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ) , total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) ,
diagnosis of diabetes ( yes / no ) , and diagnosis of any other disease ( yes / no)multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , diagnosis of any other disease ( yes / no ) , and resection radicality ( r0 , r1 , r2 ) cumulative proportion of patients without infective complications within 14 days post - surgery risk of infective complications univariate cox proportional hazard model multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) , and reported time of weight loss ( in months ) multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ) , total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , and diagnosis of any other disease ( yes / no ) multivariate cox proportional hazard model ; adjusted for age ( 50 , 5160 , 6170 , > 70 ) , stage ( i iv ) , lauren s type , type of surgery ( total or partial resection ) , nutritional status ( evaluated by total albumin level [ cutoff < 3.5 g / dl ] and total lymphocyte count [ cutoff < 1500/mm ] ) , weight loss ( in kg ) and reported time of weight loss ( in months ) , diagnosis of cardiovascular disease ( yes / no ) , diagnosis of pulmonary disease ( yes / no ) , diagnosis of diabetes ( yes / no ) , diagnosis of any other disease ( yes / no ) , and resection radicality ( r0 , r1 , r2 ) to avoid the confounding effect of surgical radicality , another model , with classification r ( 0 , 1 , 2 ) as one of possible confounding variables , was performed .
risk estimates for overall complications and infective complications were similar to those observed in the previous analyses ( tables 3 , 4 ) .
postoperative morbidity in gastric cancer remains high despite progress in perioperative care and surgical techniques .
gastrectomy for the treatment of gastric cancer is still one of the major procedures in general surgery and a 30 day postoperative complication rate of 2040% has been reported [ 1216 ] . in our study 28.3% of the patients had major or minor postoperative complications and the postoperative case - fatality rate was 3.03% .
infections were the most frequent complication ( observed in 24 patients ) , which was in line with other studies [ 3 , 17 ] .
however , in the number of infections reported , some authors included anastomotic leakage and pancreatic fistulas , as they were considered the background for secondary infections .
direct comparison of different studies was not always possible because complication types and data collection were not uniform [ 1820 ] .
the main risk factors reported in the literature are : the extent of lymphadenectomy , splenectomy , tumor size , age , comorbidities , american society of anesthesiologists ( asa ) score , malnutrition , and preoperative blood loss [ 1 , 12 , 13 , 16 , 17 , 2123 ] . some biochemical measures have also been reported as predictors of postoperative morbidity .
low serum albumin and low hemoglobin were reported as negative prognostic factors for morbidity [ 2 , 22 , 23 ] .
these factors reflect malnutrition or the need for perioperative blood transfusions . increased concentrations of c - reactive protein ( crp ) and procalcitonin corresponded with the risk of postoperative infective complications , especially pneumonia .
there is also evidence that elevated pre- or postoperative levels of cytokines , especially il-6 , may be a prognostic factor for morbidity in various surgical procedures and diseases [ 2528 ] .
this cytokine is produced rapidly after surgical trauma and the blood level increases in the hours post - surgery .
on the other hand elevated preoperative il-6 levels were observed in patients with more advanced disease .
other cytokines were sporadically reported as being associated with the risk of postoperative morbidity . a postoperative increase in il-6
was reported in several studies after stomach resection for gastric cancer [ 30 , 31 ] ; however , its influence on morbidity was not analyzed . in assessing the complications of liver surgery , liver transplantation , and cardiothoracic surgery , increased il-6 levels were indicated as a prognostic factor [ 2527 ] .
the postoperative testing of cytokines as well as other markers seems more rational than preoperative testing of cytokines concentrations , because the result depends on both tumor - related and patient - related factors and surgery . the marker should identify patients with an increased mortality and morbidity risk very early and thus enable close monitoring , additional diagnostic procedures and preventive measures , and early treatment of complications that do arise .
the univariate analysis calculated the hazard ratio ( hr ) of overall complications at 2.4 and that of infective complications at 2.51 .
both estimates were statistically significant . in the cox proportional hazard model we used covariates ( age , stage , lauren
s type , type of surgery performed , total albumin level , total lymphocyte count , weight loss , and the time of weight loss ) that might influence postoperative morbidity [ 2123 ] .
il-6 level might be an independent prognostic factor for overall ( hr = 2.79 ) and infective ( hr = 3.07 ) complications among stomach cancer patients .
when comorbidities and resection radicality were added to the regression model , the hrs were 3.08 and 3.57 , respectively , both with statistical significance .
il-6 as a marker of inflammation was observed to be higher among patients with more advanced disease .
the stage of cancer was a weak predictor of the level of il-6 in our study and the correlation coefficient observed for these two variables was only 0.15 .
the small sample size prevented us from performing reliable analysis in the subgroups of stage ; however , stage , lauren s type , and type of surgery were put in the multivariate proportional cox model as potential confounders .
it is still under question whether the same effect of the high 1st pod il-6 level on the risk of development of post - surgery complications may be expected for patients with different r scores ; however , to reveal the answer to this question , more investigations with large sample sizes are required .
the available data on the possible cutoff for the il-6 level as a predictor of complications among patients after stomach cancer surgery are very sparse .
in our study we decided to use the 90th percentile as the threshold ; however , this value characterizes our sample only .
more investigations are needed to evaluate how the proposed cutoff might be a good predictor of postsurgical complications for other groups of stomach cancer patients .
it is not clear whether the high il-6 level is metabolic or whether it is due to an individual property of patients immune cells involved in the production of increased amounts of il-6 .
some investigational data show that il-6 gene polymorphism may influence il-6 serum levels in vivo [ 33 , 34 ] .
however , in a series of cardiosurgery patients this relationship was not observed . of note
, immunomodulatory strategies have been adopted to change postoperative cytokine production and decrease inflammatory reactions , to influence morbidity [ 36 , 37 ] .
these reports describe a limited series of patients and no large clinical trial in this field has been published .
our study showed an association between perioperative il-6 serum levels and postoperative morbidity in gastric cancer patients . the first pod il-6 serum level was shown to be an independent prognostic factor for both overall complications and infective complications .
therefore , the results of our study show that the il-6 serum level could be used as an early prognostic .
the current data on the association of the il-6 serum level with postoperative morbidity among stomach cancer patients are very limited , and more investigations are required to set up the threshold level .
moreover , further investigation of the pathogenesis of high il-6 production and possible strategies to prevent complications are needed . | backgrounddespite progress in surgical techniques and perioperative care , gastrectomy remains a procedure of significant morbidity .
several scoring systems and clinical measures have been adopted to predict postoperative complications in gastric cancer patients .
the aim of this study was to investigate whether high serum levels of interleukin 6 ( il-6 ) in the early postoperative period may be a prognostic factor of postoperative morbidity.methodsa group of 99 consecutive patients with resectable gastric cancer were enrolled .
the mean age was 62.9 years and the male / female ratio was 72:27 .
subtotal gastric resection was performed in 22 patients and total gastric resection in 77 .
the il-6 serum level was measured on the 1st postoperative day ( pod).resultscomplications were recorded in 28 patients ( 28.3% ) .
the observed case - fatality rate was 3.03% . an il-6 serum level of > 288.7 pg / ml on the 1st pod in univariate and multivariate cox proportional hazard models was an independent prognostic factor for overall complications and infective complications.conclusionour study showed an association between perioperative il-6 serum levels and postoperative morbidity in gastric cancer patients .
the il-6 serum level on the 1st pod was shown to be an independent prognostic factor for both overall complications and infective complications . |
human polyomavirus and associated infection were first identified in a urine sample of a transplant recipient with ureteric stenosis in 1971 .
bk - virus - associated nephropathy ( bkvan ) was first recognized in kidney transplant recipients in 1995 .
the sequence of histopathologic events is characterized by tubular necrosis , mixed interstitial inflammatory infiltration , and finally , scarring and fibrosis of the renal interstitium .
bkv nephropathy currently affects 17% of recipients and has been associated with a 10100% graft loss rate depending on the severity of histological involvement [ 4 , 5 ] .
it is likely that the last stage of an unchecked bkv infection begins as asymptomatic viruria , progresses to sustained viremia , possibly associated with subclinical nephritis , and culminates in overt nephropathy .
thus , sustained bkv detected in plasma predicts progression to bkv - associated interstitial nephritis , or nephropathy .
jc virus and sv40 virus are other members of the family polyomaviridae and share 75% and 70% homology , respectively , with bkv .
they have three general transcription regions : the noncoding control region ( nccr ) ; the early coding region , which codes for the small and large t antigens ; and the late coding region , which codes for the viral capsid proteins vp-1 , vp-2 , and vp-3 .
the agnoprotein has recently been thought to play a role in replicative life - cycle of polyomaviruses and also in the dysregulation of cellular processes such as cell cycle control and dna repair [ 9 , 10 ] .
the nccr consists of the origin of replication and the transcription control region and is arbitrarily classified into o , p , q , r , and s regions as an aid to visualize genetic rearrangements [ 12 , 13 ] ( figure 1 ) .
these sites control the expression of the early genes , late genes , and the agnoprotein [ 13 , 14 ] .
the nccr also contains a number of transcription factor binding sites involved in the regulation of viral genes .
these include sp-1 ( specificity protein 1 ) , nf-1 ( nuclear factor 1 ) , and cre ( cyclic - amp response element ) .
additionally , promoter - enhancing sequences that control viral replication and regulate cellular oncogenes ( c - myc ) and the p53 tumor suppressor gene are found within the bkv nccr .
bkv contains a fixed number of nucleotides per nccr region . the archetypal strain of bkv ,
ww , is described as o142 , p63 , q39 , r63 , and s63 , where block o consists of 142 base pairs , block p with 63 , and so on ( figure 2 ) .
any deviation from the archetypal sequence and/or structural formula represents a genetic variation in the nccr region . although bkv strains are genotypically classified based on polymorphisms in the vp-1 region ( genotypes i iv ) , based on the nccr structure , bkv variants are classified either as archetype or as rearranged forms . therefore , bkv variants with rearranged nccrs are not considered unique strains .
initially , it was proposed that nccr rearrangements arose as an adaptation of the virus to cell culture . with the application of polymerase chain reaction ( pcr ) technology
, one can amplify and sequence the naturally occurring nccr from clinical specimens , to determine whether a rearrangement has occurred .
the archetypal bk - nccr structure is the most common form found in the urine .
it has been suggested that in permissive cells the virus replicates and gives rise to rearranged enhancers [ 14 , 17 ] , which permit viral species to adjust to transcription conditions within the cell .
this might explain the occurrence of bkv variants in specific tissues and under different clinical conditions ; however , the mechanisms or pressures , such as immunosuppression , regulating the rearrangement events are unclear . although associations of rearranged viral strains with greater replication propensity have been described , most publications are based on very small data sets [ 5 , 7 ] .
relationships between genetic rearrangement , viral genotype , tissue tropism , geographic distribution , pathogenicity , and progression of disease remain inadequately studied .
in addition to genomic rearrangements , genetic variation in the bk - nccr can arise from point mutations , deletions , and duplications of the basic sequence elements and can affect the transcriptional , transformational , and replicative potential of the bkv variant . functional promoter analysis and computational approaches
have identified a number of transcription factor binding sites within the bk - nccrs , such as a cre within the p block , two sp-1 binding elements within the q and r blocks , and four nf-1 binding sites within the p , q , r , and s blocks .
although the coding region of the bkv genome is highly conserved , minimal variations in the late region encoding the major viral capsid protein vp-1 allow bkv to be divided into four genotypes ( i iv ) .
a variety of genomic rearrangements have been detected in the nccr of the related human polyomavirus , for example , jc virus taken from the brain tissue of patients with progressive multifocal leukoencephalopathy ( pml ) .
these rearrangements seem to be crucial in permitting viral replication in the brain and the lysis of oligodendrocytes .
this is gaining increased clinical relevance given the increased incidence and black box warnings regarding progressive multifocal leukoencephalopathy ( pml ) associated with the use of mycophenolate mofetil and belatacept .
one study demonstrated that bkv subtype i was predominant in urine samples from bone marrow transplant recipients with hemorrhagic cystitis .
other potential viral determinants of hemorrhagic cystitis included overrepresentation of cytosine ( c ) to guanosine ( g ) mutations in the nccr sp-1 binding site , limited to 7 of 13 patients with hemorrhagic cystitis .
however , these alterations were not associated with increased urinary bkv loads , arguing against the pathogenicity of these variants .
a number of bkv - dna sequence variants have been described in the form of point mutations ( transitions and transversions ) , duplications , deletions , and rearrangements localized to the nccr of the viral dna in renal transplant patients , but they were not associated with disease .
, however , reported the presence of nccr rearrangement in 3 of 5 ( 60% ) biopsies with bkvan .
although they concluded that the nccr rearrangements did not necessarily correlate with the stage of bkvan , the presence of rearrangements in the majority of bkvan samples suggests a pathogenic role of rearrangement in progression of bk virus infection .
similarly , olsen et al . reported an incidence of rearrangement of nccr region in 50% of patients with bkvan .
a study of 30 renal transplant recipients with bk viremia did not show any changes in the nccr region in the urine or plasma samples with high titer viruria or viremia but none of these recipients developed bkvan .
thus , studies evaluating the rearrangement or mutation in the nccr as a factor in the pathogenesis and virulence of bk virus have involved small numbers of patients and have not been definitive .
the purpose of this study was to determine whether the presence of nccr rearrangements or mutations in the urine and blood of patients with sustained bk viremia , a surrogate of bkvan , was associated with progression from bk viruria .
from december 2000 to october 2002 , 200 de novo kidney transplant recipients were enrolled in a prospective open label trial and randomized to receive tacrolimus or cyclosporine in a 2 : 1 block - design fashion stratified by race and gender as previously described .
recipients were prospectively monitored for the development of bk viruria , viremia , and nephropathy .
identification of bk viremia triggered discontinuation of the antimetabolite component of the immunosuppressive regimen upon detection of bk - viremia and reduction in the calcineurin component upon detection of sustained viremia to prevent progression of viremia to nephropathy .
clinical data and frozen plasma and dna samples collected during 1-year of follow - up were analyzed based on the development of bk viruria , any viremia , and sustained viremia , defined as 2 consecutive bkv positive plasma samples spanning 3 weeks .
for the purposes of this study we selected samples from the eleven patients with sustained viremia ( as defined here in after ) around the time of peak viral load in blood .
the washington university human studies committee approved the study , and all patients gave informed consent for the initial and follow - up studies .
samples consisted of undiluted whole blood , plasma , and urine samples collected before -transplant , weekly for 16 weeks , and at months 5 , 6 , 9 , and 12 .
we identified 11/200 ( 6% ) of patients with sustained bk viremia and high urine viral load in our cohort .
we selected one urine and two plasma samples from each patient near the time of highest blood viral load as viremia correlates with tissue invasive disease .
established qualitative pcr for detection of bkv dna was used as previously described and performed in a diagnostic clinical laboratory [ 16 , 23 ] .
briefly , dna was extracted and purified from urine and plasma using qiaamp spin columns ( qiagen inc . ,
extracted dna was tested for bk virus dna by real - time pcr using the light cycler system ( roche diagnostics corporation , indianapolis , in ) using the primers , pep-1 agt ctt tag ggt ctt cta cc and pep-2 ggt gcc aac cta tgg aac ag , which amplify a 176-basepair segment of the bk virus large t - antigen gene . bk virus - specific hybridization probes 5-ttg cca tga aga tat gtt tgc cag tga tga fitc-3 and 5-lcred640 gaa gca aca gca gat tct ca_3 ( tib molbiol llc , adelphia , nj ) were used for detection .
these probes were designed to detect bk virus without detection of the related polyoma viruses , jc virus and sv-40 .
reactions were carried out in a 20 l volume that included 2 l of roche light cycler faststart dna hybridization probe 10 reaction mix and 2 l of sample dna .
the final concentrations of other components were 3.5 mm mgcl2 , 0.5 m of each primer and 0.2 m of each probe .
the reaction program consisted of denaturation for 7 minutes at 95c followed by 45 cycles of denaturation at 95c instantaneous , annealing at 52c for 10 seconds , and extension at 75c for 7 seconds .
each reaction included positive controls consisting of 1000 copies of bk virus plasmid dna ( atcc 45026 ) obtained from the american type culture collection ( atcc , manassas , va ) and negative controls for amplification and dna preparation .
bk - positive samples were quantified by repeat real - time pcr analysis of aliquots of extracted dna that had been frozen at 80c , alongside a standard curve of control bkv dna ( 2 10 , 2 10 , 2 10 , and 2 10 ) .
the standards were prepared from a plasmid ( pbkv [ 35 - 1 ] ) that contains the entire linearized bkv genome ( atcc 45026 ) and was quantified by spectrophotometry .
the coefficient of variability for the quantitative bkv lightcycler assay in our laboratory was less than 6% .
the lower limit of sensitivity of the quantitative pcr assay is 10000 copies / ml . nested pcr was carried out using the following protocol . the first round pcr with primers nccr 722r ( 5 to 3 ) tttcccgtctacactgtcttcacc and nccr 128f ( 5 to 3 ) cccaggcagctctttcaagg amplified a 596-bp fragment of bkv , including the nccr . the nested pcr reaction used primers nccr 596 r ( 5 to 3 ) tgacagctggcgcagaacc and nccr 164f ( 5 to 3 ) gctccatggattcttccctgttaagc which amplified a 432 bp fragment of the previous pcr product .
the dna amplification reactions were carried out in 100 l volumes with 10 l of patient or control dna , 1.25 l of taq dna polymerase ( invitrogen , carlsbad , ca ) , 1.25 l of each primer , and 5 l of pcr buffer including deoxynucleoside triphosphates .
the dna amplification reactions for the nested pcr were carried out in 100 l volumes with 5 l of from the initial reaction product , 1.875 l of taq dna polymerase ( invitrogen , carlsbad , ca ) , 1.875 l of each primer , and 7.5 l of pcr buffer including deoxynucleoside triphosphates .
thermal cycling comprised an initial hot start at 94c for 3 minutes followed by 30 cycles of 68c for 45 seconds and the final step at 68c for 1 minute .
the pcr products were visualized on a uv transilluminator , followed by gel electrophoresis in 2% agarose gels containing ethidium bromide .
the pcr products were purified using a minelute pcr purification kit ( qiagen , valencia , ca ) .
single - band pcr products of both strands were sequenced using bigdye terminator dna - sequencing techniques ( applied biosystems , foster city , ca ) using both the forward and reverse primers of the nested pcr reaction and the sequencing data were analyzed using vector nti software ( invitrogen , carlsbad , ca ) to obtain a consensus sequence using both strands .
our prior studies showed that bk virus dna was detected in urine samples from 70 recipients ( 35% of the 198 with samples available for analysis ) .
bk viremia never occurred in the absence of viruria and followed or was contemporaneous with bk viruria .
no clinically evident bkvan was seen by 12 months , and none had been seen at the last date of observation .
however , one patient had insufficient dna in the urine sample to allow for further amplification , and we were not able to amplify the bk virus in one of the plasma samples in two patients and in both plasma samples in one patient .
thus , we had 28 complete nccr sequences to analyze . among the 11 patients with sustained viremia , the mean viral load in the plasma samples was 5.08 log10 copies / ml ( range 2.5 log105.90 log10 copies / ml ) , with a median of 5.49 log10 copies / ml .
the mean viral load in the urine samples was 10.3 log10 copies / ml ( range 8.32 log1012.02 log10 copies / ml ) , with a median of 10.17 log10 copies / ml . given the magnitude of our viral load we expected to find significant rearrangements , that is , the addition of whole blocks in the nccr regions of the amplification product .
we did not find any significant change when compared to control ( atcc 45026 ) .
only two of our plasma samples showed two different bands on gel electrophoresis which were only 25 bp different from the control suggesting that there might be smaller mutations in our samples ( figure 3 ) .
thus , we further examined our products after dna sequencing to assess for small changes in the sequence .
we only found small changes in the bk virus genome ( table 1 ) . in total , we found 8 insertions , 16 transversions , 3 deletions , and 17 transitions .
we defined transitions as a pyrimidine nucleotide replacing a pyrimidine and a transversions as a replacement of pyrimidine with a purine or vice versa .
however , no significant rearrangements or sequence variations such as duplications or inversions were identified .
based on observation studies , it is thought that bk virus infection occurs due to the failure in the balance between bk virus replication and natural immunological control of that process resulting in bkvan .
in addition to host factors , it is hypothesized that various viral factors contribute to the pathogenesis of bkvan .
to date all studies looking at these factors have been uncontrolled and small and only suggestive of the possibility of a viral determinant of bkvan .
it has been reported that bkv variants with rearranged nccr are present in immunocompromised patients with kidney transplants [ 18 , 21 , 26 ] . in a retrospective analysis of matched urine and plasma samples from patients with any bk viremia of which 70 had bkvan , gosert et al . reported that rearranged nccr variant bkv replaced the wild type in 24% of kidney transplant patients with persistent bk viremia and in 50% of patients with bkvan .
bk virus with rearranged nccr had a 20-fold higher median viral load and higher probability of histologically confirmed disease when compared to wild type nccr bkv .
rearranged nccr was detectable in patients with peak viral load of 6.5 log10 genome equivalents(geq)/ml for < 4 months , whereas a 100-fold lower viremia required > 7 times longer times suggesting that the duration and higher peak viral load favored the change from the wild type , ww - nccr , to rearranged , rr - nccr , as a majority species .
they confirmed the role of rearrangements in the nccr and polyomavirus nephropathy in a prospective cohort of 73 plasma samples from 227 kidney transplant recipients of which 39 had bkvan .
the role of rearranged nccr was further confirmed in elegant in vitro studies using a novel bidirectional reporter replicon that mimics polyoma replication .
their patients were not in a clinical trial and no systematic intervention such as reduction in immunosuppression was used for clinical management of viremia .
our patients were in a clinical trial , and since we promptly reduced immunosuppression upon detection of viremia , none of our patients developed very high viral loads ( peak viral load of 5.90 log10 copies / ml ) for more than a month .
thus , our study supports the findings of gosert et al . and explains the absence of rearranged nccr in our samples .
bressollette - bodin et al . reported results showing that nccr mutation or rearrangement was not present in patients with viremia or viruria .
the number of samples with high titer viremia and viruria was lower than that of our patients and bkvan was not observed .
it is unclear whether this was due to the fact that their immunosuppression regimen was different than ours including a prednisone - free regimen and their follow - up was for only a year .
thus it can not be concluded if and when their patients developed bkvan and whether the nccr mutation may have occurred .
thus , we could not determine whether changes in the bk - nccr region might be associated with progression from sustained bk - viremia to bkvan .
significantly , the peak viral load in our patients was lower than that in the study by gosert et al . perhaps as a consequence of our clinical management of immunosuppressive reduction upon detection of bk - viremia .
our interventional strategy of withdrawal of the antimetabolite and further reduction in immunosuppression with persistence of sustained viremia may have removed the selective pressure that would have led to rearrangements and subsequent development of bkvan .
there may also be a threshold of viral load that may determine tissue invasive disease , that is , a higher load being suggestive of aggressive disease with mutation or pathogenetic rearrangements in the nccr .
the major limitation of this study is that there was no clinically evident bkvn ; hence it can not be assumed that if it had occurred , it may have resulted from changes in the nccr . given the serious impact of bk viremia , we felt that it was unethical simply to follow the patients without intervention .
our strategy was successful in the short and long term and resulted in excellent clinical outcomes [ 16 , 23 , 27 ] .
the current study provides translational and mechanistic support , at a genomic level , for our interventional approach .
although the sample size , n = 11 , of patients with sustained viremia , a surrogate of bkvan , is small , it is the largest such assessment to date looking at whether nccr arrangements are associated with sustained viremia .
sustained viremia in our study in association with significant immunosuppression withdrawal upon detection of bk viremia was not associated with rearrangement and/or sequence variation in the nccr region of the bk virus .
our findings do not exclude the possibility of an association between transition from sustained bk viremia to bkvan based on nccr rearrangement or sequence variation .
our data , however , support the effectiveness of a clinical interventional approach of withdrawal and reduction of immunosuppression upon detection of sustained bk - viremia for prevention of progression from sustained viremia to bkvan that may have removed the immunosuppressive selective pressure for mutation of the virus that may have led to progression of disease . | changes in the bk virus archetypal noncoding control region ( nccr ) have been associated with bk - virus - associated nephropathy ( bkvan ) .
whether sustained viremia , a surrogate for bkvan , is associated with significant changes in the bk - nccr is unknown .
we performed pcr amplification and sequencing of ( 1 ) stored urine and ( 2 ) plasma samples from the time of peak viremia from 11 patients with sustained viremia who participated in a 200-patient clinical trial .
the antimetabolite was withdrawn for bk viremia and reduction of the calcineurin inhibitor for sustained bk viremia .
dna sequencing from the 11 patients with sustained viremia revealed 8 insertions , 16 transversions , 3 deletions , and 17 transitions .
none were deemed significant .
no patient developed clinically evident bkvan .
our data support , at a genomic level , the effectiveness of reduction of immunosuppression for prevention of progression from viremia to bkvan . |
cellular drug resistance can be defined as a lack of cytotoxic response in cancer cells after administration of a cytotoxic compound .
response of cancer cells to chemotherapy can be tested in ex vivo conditions by several assays , such as the methylthiazol tetrazolium ( mtt ) assay , differential staining cytotoxicity ( disc ) assay , the fluorometric microculture cytotoxicity assay ( fmca ) and similar assays .
considerable work based on these assays has been reported during the past 25 years , and recently an ad hoc group of 50 scientists from 10 countries agreed on the term
individualized tumor response ( itrt ) for these tests , describing them as the effect of anticancer treatments on whole living tumor cells freshly removed from cancer patients and not including tests with subcellular fractions , animals or cell lines [ 1 , 2 ] .
itrt is regarded as an important risk factor of treatment failure in pediatric acute lymphoblastic leukemia ( all ) .
it can be demonstrated clinically as a poor steroid response after one - week monotherapy or as a delayed response of bone marrow at day + 15 or day + 33 of induction therapy .
presence of minimal residual disease also results in drug resistance . in comparison to pediatric all , the value of itrt assays is less established in other types of leukemia , especially in chronic myeloid leukemia ( cml ) .
introduction of tyrosine kinase inhibitors ( tkis ) in therapy of cml has contributed to development of ex vivo testing in this disease .
so far only very limited data on cellular drug resistance in cml cells are available [ 36 ] .
the objective of the study was to analyze the ex vivo drug resistance profile to bortezomib and 22 other antileukemic drugs , including three tyrosine kinase inhibitors ( tkis ) , in cml in comparison to acute myeloid leukemia ( aml ) .
a total of 82 patients entered the study , including 36 cml and 46 aml adults ( age 1869 , median 41 years ) .
however , due to technical reasons , not all drugs were tested for all patients .
aml patients were diagnosed for de novo ( n = 20 ) or relapsed ( n = 26 ) disease .
cml patients were divided into the following subgroups : with advanced ( n = 19 ) or non - advanced ( n = 17 ) disease ; with good ( n = 20 ) or poor clinical response to imatinib ( n = 16 ) ; with ( n = 6 ) or without mutation ( n = 28 ) .
all patients with a poor clinical response were tested for abl - kinase domain mutations . among cml patients ,
19 had advanced disease , 16 were resistant to imatinib , and 6 had abl - kinase domain mutations ( m244v , e255k , y253h , m351 t and 2 with f317l ) .
the following 20 drugs were used : bortezomib ( velcade , janssen pharmaceutica n.v . ,
beerse , belgium ; concentrations tested : 0.000192 m ) , prednisolone ( jelfa , jelenia gra , poland ; 0.0076250 g / ml ) , vincristine ( gedeon richter , budapest , hungary ; 0.01920 g / ml ) , l - asparaginase ( medac , hamburg , germany ; 0.003210 iu / ml ) , daunorubicin ( rhone - poulenc rorer , paris , france ; 0.00192 g / ml ) , doxorubicin ( pharmacia italia s.p.a . ,
milan , italy ; 0.03140 g / mlz , cytarabine ( upjohn , puurs , belgium ; 0.24250 g / ml ) , cladribine ( bioton , warsaw , poland ; 0.000440 g / ml ) , etoposide ( bristol - myers squibb , sermoneta , italy ; 0.04850 g / ml ) , thiotepa ( lederle , wolfratshausen , germany ; 0.032100 g / ml ) , topotecan ( glaxo smithkline manu - facturing s.p.a . , parma , italy ; 0.097100 g / ml ) , busulfan ( busilvex , pierre - fabre - medicament , castres , france ; 1.17 1200 g / ml ) , 4-hoo - cyclophosphamide ( asta medica , hamburg , germany ; 0.096100 g / ml ) , fludarabine phosphate ( schering ag , berlin , germany ; 0.01920 g / ml ) , idarubicin ( pharmacia , milan , italy ; 0.00192 g / ml ) , melphalan ( glaxo wellcome , parma , italy ; 0.03840 g / ml ) , mitoxantrone ( jelfa ; 0.0011 g / ml ) , 6-thioguanine ( sigma , nr a4882 ; 1.5650 g / ml ) , treosulfan ( medac ; 0.00051 g / ml ) , and clofarabine ( bioenvsion / genzyme , 0.0112.5 m ) .
before the assay was carried out , most drug stock solutions were stored frozen in small aliquots at 20c , except cladribine , which was stored at + 4c .
stock solutions were prepared in water for injection , and further dilution was made in respective medium .
cml patients were also tested for sensitivity to tyrosine kinase inhibitors : imatinib ( novartis pharmaceuticals ; concentrations tested : 0.0009771 m ) , dasatinib ( bristol meyers squibb ; 0.0009771 m ) and nilotinib ( novartis pharmaceuticals ; 0.0009771 m ) .
ex vivo drug resistance profile ( itrt ) was studied by the mtt assay .
the concentration of drug that was lethal to 50% of the cells ( lc50 ) was calculated from the dose response curve and was used as a measure for ex vivo drug resistance in each sample . relative resistance ( rr ) between
analyzed groups for each drug was calculated as the ratio of median values of lc50 for this drug in each group .
results of aml patients were published previously . due to similar profiles of drug sensitivity ,
the mann - whitney u test was performed to compare differences in drug resistance between groups .
a total of 82 patients entered the study , including 36 cml and 46 aml adults ( age 1869 , median 41 years ) .
however , due to technical reasons , not all drugs were tested for all patients .
aml patients were diagnosed for de novo ( n = 20 ) or relapsed ( n = 26 ) disease .
cml patients were divided into the following subgroups : with advanced ( n = 19 ) or non - advanced ( n = 17 ) disease ; with good ( n = 20 ) or poor clinical response to imatinib ( n = 16 ) ; with ( n = 6 ) or without mutation ( n = 28 ) .
all patients with a poor clinical response were tested for abl - kinase domain mutations . among cml patients ,
19 had advanced disease , 16 were resistant to imatinib , and 6 had abl - kinase domain mutations ( m244v , e255k , y253h , m351 t and 2 with f317l ) .
the following 20 drugs were used : bortezomib ( velcade , janssen pharmaceutica n.v . , beerse , belgium ; concentrations tested : 0.000192 m ) , prednisolone ( jelfa , jelenia gra , poland ; 0.0076250 g / ml ) , vincristine ( gedeon richter , budapest , hungary ; 0.01920 g / ml ) , l - asparaginase ( medac , hamburg , germany ; 0.003210 iu / ml ) , daunorubicin ( rhone - poulenc rorer , paris , france ; 0.00192 g / ml ) , doxorubicin ( pharmacia italia s.p.a . , milan , italy ; 0.03140 g / mlz , cytarabine ( upjohn , puurs , belgium ; 0.24250 g / ml ) , cladribine ( bioton , warsaw , poland ; 0.000440 g / ml ) , etoposide ( bristol - myers squibb , sermoneta , italy ; 0.04850 g / ml ) , thiotepa ( lederle , wolfratshausen , germany ; 0.032100 g / ml ) , topotecan ( glaxo smithkline manu - facturing s.p.a . , parma , italy ; 0.097100 g / ml ) , busulfan ( busilvex , pierre - fabre - medicament , castres , france ; 1.17 1200 g / ml ) , 4-hoo - cyclophosphamide ( asta medica , hamburg , germany ; 0.096100 g / ml ) , fludarabine phosphate ( schering ag , berlin , germany ; 0.01920 g / ml ) , idarubicin ( pharmacia , milan , italy ; 0.00192 g / ml ) , melphalan ( glaxo wellcome , parma , italy ; 0.03840 g / ml ) , mitoxantrone ( jelfa ; 0.0011 g / ml ) , 6-thioguanine ( sigma , nr a4882 ; 1.5650 g / ml ) , treosulfan ( medac ; 0.00051 g / ml ) , and clofarabine ( bioenvsion / genzyme , 0.0112.5 m ) . before the assay
was carried out , most drug stock solutions were stored frozen in small aliquots at 20c , except cladribine , which was stored at + 4c .
stock solutions were prepared in water for injection , and further dilution was made in respective medium .
cml patients were also tested for sensitivity to tyrosine kinase inhibitors : imatinib ( novartis pharmaceuticals ; concentrations tested : 0.0009771 m ) , dasatinib ( bristol meyers squibb ; 0.0009771 m ) and nilotinib ( novartis pharmaceuticals ; 0.0009771 m ) .
ex vivo drug resistance profile ( itrt ) was studied by the mtt assay .
the concentration of drug that was lethal to 50% of the cells ( lc50 ) was calculated from the dose response curve and was used as a measure for ex vivo drug resistance in each sample . relative resistance ( rr ) between
analyzed groups for each drug was calculated as the ratio of median values of lc50 for this drug in each group .
results of aml patients were published previously . due to similar profiles of drug sensitivity ,
the mann - whitney u test was performed to compare differences in drug resistance between groups .
in comparison to adult aml , cml blasts were more resistant to bortezomib ( 6.2-fold ; p < 0.001 ) , and to the following other drugs : prednisolone ( 1.5-fold ; p = 0.037 ) , vincristine ( 2.3 ; p = 0.004 ) , doxorubicin ( > 6.9 ; p < 0.001 ) , etoposide ( 7.4 ; p < 0.001 ) , melphalan ( 5.9 ; p = 0.001 ) , cytarabine ( 12.5 ; p = 0.005 ) , fludarabine ( 2.6 ; p = 0.008 ) , thiotepa ( 5.4 ; p = 0.001 ) , 4-hoo - cyclophosphamide ( 2.3 ; p = 0.015 ) , thioguanine ( > 4 ; p < 0.001 ) , topotecan ( 20 ; p < 0.001 ) , and clofarabine ( 50 ; p < 0.001 ) . no differences in sensitivity were found for idarubicin , daunorubicin , mitoxantrone , l - asparaginase , cladribine , and treosulfan , while cml cells were 2-fold more sensitive to busulfan ( p = 0.035 ) ( table 1 ) .
drug resistance in adult aml and adult cml lc50 value of in vitro resistance , given in iu / ml for l - asparaginase and in g / ml for other drugs ; rr relative resistance = median lc50 ( cml)/median lc50 ( aml ) ; n the number of patients ; p - value mann - whitney u - test cml patients were divided into subgroups ( table 2 ) .
overall , no significant differences for all tested drugs , including tkis , were observed between cml patients with non - advanced and advanced disease .
cml patients with poor clinical response expressed as clinical resistance to imatinib had higher median lc50 values for vincristine ( 2.5-fold ; p = 0.016 ) , daunorubicin ( 3.1-fold ; p = 0.011 ) , etoposide ( 2.2-fold ; p = 0.031 ) , and busulfan ( 4.5-fold ; p = 0.032 ) .
no significant differences were observed with respect to other drugs , including all 3 tkis .
cml patients with mutation had higher median lc50 values for vincristine ( 3.3-fold ; p = 0.044 ) , idarubicin ( > 7.9-fold ; p = 0.031 ) , thiotepa ( 13.7-fold ; p = 0.044 ) , and busulfan ( 21.6-fold ; p = 0.024 ) .
no significant differences were observed with respect to other drugs , including all 3 tkis ( table 2 ) .
drug resistance in cml patients with respect to phase of the disease , clinical response to imatinib , and abl - kinase domain mutation the value of the drug resistance for each group is presented as the median value of all lc50 values in this group .
lc50 value of in vitro resistance , given in iu / ml for l - asparaginase and in g / ml for other drugs ; rr relative resistance = median lc50 ( cml ) / median lc50 ( aml ) ; ne not evaluable ; p - value ( by mann - whitney u - test )
therapy of cml has been significantly improved with the use of bcr - abl kinase inhibitors .
however , the existence of cml cells that are unaffected by bcr - abl inhibition represents a major barrier that may prevent curative therapy with the current approaches . to date
, it seems that resistance to tyrosine kinase inhibitor - based therapies involving bcr - abl gene mutations and amplification is the most important mechanism of therapy failure .
new evidence suggests that persistence of cml stem cells or acquisition of stem cell - like characteristics may prevent complete elimination of cml by tkis .
the proteasome inhibitor bortezomib is a potent in vitro cytotoxic compound against stem cells in acute and chronic myeloid leukemias [ 10 , 11 ] .
poor therapy outcome , especially in patients with relapsed and refractory leukemia , might be related to intrinsic drug resistance . in our previous ex vivo analysis
we showed the benefit of use of bortezomib in adult patients with relapsed / refractory aml .
differences in in vitro sensitivity of leukemic cells to bortezomib are related to variability in the activity profiles of the individual proteasomal subunits between primary leukemia cells .
in addition to drug resistance , an aberrant activation of signal transduction proteins , including the nf-b pathway , is one of the key mechanisms of treatment failure in aml [ 12 , 13 ] .
activity of bortezomib in aml and cml , which also acts through the nf-b pathway , is an important aspect , being investigated in both in vitro and in vivo studies [ 14 , 15 ] .
bcr - abl plays an essential role in the pathogenesis of cml and some cases of all .
although abl kinase inhibitors have shown great promise in the treatment of cml , the persistence of residual disease and the occurrence of resistance have prompted investigations into the molecular effectors of bcr - abl .
provided a novel insight into the molecular effects of proteasome inhibitor therapy and showed that bcr - abl stimulated the proteasome - dependent degradation of members of the forkhead family of tumor suppressors in vitro , in an in vivo animal model , and in samples from patients with bcr - abl - positive cml .
they showed that inhibition of this pathway , using bortezomib , caused regression of cml disease .
bortezomib treatment led to inhibition of bcr - abl - induced suppression of foxo proteins and their proapoptotic targets , and tumor necrosis factor - related apoptosis - inducing ligand .
their study provided evidence that bortezomib induced apoptosis of cml cells in vitro and might be a candidate therapeutic in the treatment of bcr - abl - induced leukemia .
our study , based on the mtt assay , which is an endpoint type analysis , has shown that in comparison to aml cells , bortezomib alone has little ex vivo activity against cml cells .
this was observed both for the whole group and for all subsets of patients tested in the study .
recently published results of a pilot study of bortezomib therapy for patients with imatinib - refractory chronic myeloid leukemia in chronic or accelerated phase , performed in the md anderson cancer center in houston , have also shown only minimal efficacy , but considerable toxicity in patients with imatinib - refractory cml .
the introduction of bcr - abl1 tyrosine kinase inhibitors during the last decade resulted in long - term disease control in the majority of patients with cml . in those who fail to respond and/or
possibly , combined use of a tyrosine kinase inhibitor and proteasome inhibitor might be helpful for optimizing treatment of refractory / resistant cml .
new possibilities can arise with new modalities , related to immunotherapy or other targeted therapy [ 19 , 20 ] .
further studies should focus on alternative approaches in using proteasome inhibitors in the treatment of cml , such as in combination with tkis or as a strategy to eradicate leukemic stem cells [ 18 , 21 ] . | aim of the studyresistance to imatinib is one of the most important issues in treatment of chronic myeloid leukemia ( cml ) patients .
the objective of the study was to analyze the ex vivo drug resistance profile to bortezomib and 22 other antileukemic drugs , including three tyrosine kinase inhibitors ( tkis ) , in cml in comparison to acute myeloid leukemia ( aml).material and methodsa total of 82 patients entered the study , including 36 cml and 46 aml adults . among cml patients ,
19 had advanced disease , 16 were resistant to imatinib , and 6 had abl - kinase domain mutations .
the ex vivo drug resistance profile was studied by the mtt assay.resultscml cells were more resistant than aml blasts to the following drugs : prednisolone , vincristine , doxorubicin , etoposide , melphalan , cytarabine , fludarabine , thiotepa , 4-hoo - cyclophosphamide , thioguanine , bortezomib , topotecan , and clofarabine .
cml cells were 2-fold more sensitive to busulfan than aml cells .
cml patients with clinical imatinib resistance had higher ex vivo resistance to vincristine , daunorubicin , etoposide , and busulfan .
no significant differences to all tested drugs , including tkis , were observed between cml patients with non - advanced and advanced disease .
cml patients with mutation had higher ex vivo resistance to vincristine , idarubicin , thiotepa , and busulfan.conclusionscml cells are ex vivo more resistant to most drugs than acute myeloid leukemia blasts .
busulfan is more active in cml than aml cells . in comparison to aml cells , bortezomib has little ex vivo activity in cml cells .
no differences between cml subgroups in sensitivity to 3 tested tkis were detected . |
giant cell lesions of the maxillofacial area can vary from asymptomatic radiolucency of slowly growing lesion to aggressive tumours showing high recurrence rate as well as rapid expansive progression characterized by root resorption and pain .
gcgs of the jaws arise either peripherally in periodontal ligament , mucoperiosteum , or centrally in the bone .
the world health organization has defined the central giant cell granuloma as an intraosseous lesion consisting of cellular fibrous tissue that contains multiple foci of hemorrhage , aggregations of multinucleated giant cells and occasionally trabeculae of woven bone .
histologically , both peripheral and central variants of giant cell granuloma are characterized by the presence of numerous multinucleated giant cells ( mgcs ) in a prominent fibrous stroma .
foci of hemorrhage with liberation of hemosiderin pigment and newly formed osteoid or bone are often seen .
the mgcs are concentrated in the areas of hemorrhage and are adjacent to blood vessels .
jaffe separated cgcg from gct of the bone on clinical and histologic grounds and suggested that mgcs in cgcg represent a phagocytic response to hemorrhage .
however , it affects females more often than males , in a 2:1 ratio and is seen most frequently under the age of 30 years .
one study of 38 patients shows 74% to be less than 30 years of age and 61% to be less than 20 years of age .
the lesion commonly presents as a solitary radiolucency with a multilocular appearance or less commonly , a unilocular appearance .
it is more prevalent in the anterior than the posterior jaws , often crossing the midline , and the mandible is more commonly affected than the maxilla .
this lesion has also been reported in the small bones of the hands and feet .
the behavior of cgcg is variable , most commonly producing an asymptomatic expansion of the jaws .
however , it can be clinically aggressive , associated with pain , osseous destruction , cortical perforation , root resorption , and recurrence
. cases of cgcg occurring with neurofibromatosis ( type 1 ) , noonan - like syndrome , or both have been reported .
these lesions may possibly lead to a confusion in their correct diagnosis as many pathologists report them taking into consideration one of the prominent histopathologic feature .
such misinterpretation may be because of the small number of cases reported in the literature with uncertain clinical , radiographic and histopathologic features of these lesions .
so even surgeons may end up treating these lesions inadequately or patients may need to undergo multiple surgeries .
the present case report highlights a case of recurrent and aggressive form of cgcg in the mandible .
a 22-year - old man presented with a swelling in the left ramus of the jaw 2 years ago .
examination revealed a unilocular radiolucent lesion , with a scalloped inferior border [ figure 1 ] .
the ct scan revealed a well defined hyperdense soft tissue seen in the region of and below the left coronoid process of mandible , with suspicion of sclerosis .
a partial mandibulectomy was performed and a reconstruction plate with a mini plate at the anterior region along with a fibular graft in the jaw was inserted to repair the defect [ figure 2 ] .
the inferior border of the lesion is scalloped orthopantomograph showing the reconstruction plate repairing the defect in the left jaw after one year , the patient , now 23 years old , complained of a recurrent swelling in the same region .
intraorally , the patient presented with a growth in the left buccal mucosa at the level of the occlusal plane , which was excised and microscopically reviewed .
the first molar along with the premolars were removed , the region was curetted and a new reconstruction plate was given .
photomicrograph confirming the presence of granulomatous lesion ( h and e , 40 ) a year later , the patient now 24 years old , was referred to the department of oral surgery with the complaint of pain and recurrent swelling of the left jaw [ figure 4 ] .
extra oral swelling of the left lower jaw clinically the lesion extended from the corner of the mouth to the anterior part of tragus on the left side , which was 4 4 cm in size , irregular in shape with a rough texture .
the swelling was hard in consistency , showed no secondary changes and was non tender on palpation .
intraoral examination revealed an exophytic growth present posteriorly near the junction of the buccal mucosa and pterygomandibular fossa region , at the level of the occlusal plane , sized 1 1.5 cm and soft in consistency .
presently the ct scan revealed an evidence of an expansile destructive mass ( 4.3 3.8 4.3 cm in the maximum anteroposterior , transverse and superoinferior dimensions ) in the expected location of the left coronoid process , with thin residual septae like areas of osseous density seen in a large soft tissue mass .
this soft tissue mass showed near isodensity compared to the adjacent muscles of the left masseteric space .
the lesion expanded the insertion of the left temporalis muscle and bulged anteriorly into the left buccal space and posteriorly into the left condylar head and neck and left parotid gland .
medially , the lesion led to mild pressure erosion with thinning of the buccal cortex of the left maxillary tuberosity and bulged against the left medial pterygoid muscle [ figure 6 ] .
intra oral photograph depicting exophytic growth in the junction of the left pterygomandibular fossa region and buccal mucosa ct scan showing the extent of the lesion during the second recurrence routine hemogram and urine examination were normal .
on the basis of clinical and radiological examination a provisional diagnosis of cgcg was made .
the serum chemistry of calcium , phosphorous , parathyroid hormone was normal , there by excluding the possibility of hyperparathyroidism .
surgery was performed by a submandibular incision at the site of the previous scar , with the removal of the reconstruction plate , mini plate and graft , along with the condyloid process .
histopathological examination of excised specimen revealed evenly dispersed ( 2 - 3/hpf ) giant cells each having 2 - 8 nuclei in them , in close approximation with proliferating blood vessels admixed with areas of haemorrhage .
even the bone graft attached to the condyle showed the presence of tumor giant cells [ figure 8 ] .
no recurrence was noticed in post operative follow - up phase of 3 years [ figures 9 and 10 ] and further reconstruction of mandible using iliac crest graft is intended .
photomicrograph showing giant cells in a vesiculated fibroblast connective tissue stroma ( h and e , 40 ) photomicrograph showing presence of giant cells near the condylar region ( h and e , 40 ) post - operative follow up opg verifying the absence of lesion post - operative intraoral view
the etiopathogenesis of the cgcg of jawbones has not been clearly established but it has been suggested that it is the result of an exacerbated reparative process related to previous trauma and intraosseous hemorrhage that triggers the reactive granulomatous process .
donoff and rosenberg discussed a case record of an uncomplicated extraction because of pericoronitis in the area of the lesion and claimed the local changes in the blood flow throughout the bone and local bone dysplasia could be probable etiologic factors .
unal et al . , presented a 12-year - old girl cgcg in the mandible caused by a molar tooth extraction and explained the pathogenesis by a traumatic aetiology .
association of t ( x ; 4)(q22;q31.3 ) in the etiology of gcg has been reported .
although , cgcgs are benign osseous lesions , some authors separate cgcg into two types , referring to its clinical and radiographic features : ( a ) nonaggressive lesion is usually slow growing and asymptomatic , does not show cortical resorption by the lesion or root perforation in teeth affected , and it is significantly less likely to recur than the aggressive type ; and ( b ) aggressive lesions , is usually found in younger patients and is painful , grows rapidly , is larger , often causes cortical perforation and root resorption and has a tendency to recur .
predicting the behavior of cgcgs that will exhibit a higher risk of recurrence after treatment has been problematic .
waldron reported a mean interval between diagnosis and initial treatment and treatment of a recurrence was 21 months , and stated that very few recurrences were manifested after 2 years of initial treatment .
the most reliable factors related to an increased risk of recurrence include clinical activity of lesions ( 72% of recurrence in the aggressive forms , 3% of recurrence in the nonaggressive forms ) , younger patients , demonstrated perforation of cortical bone and tumor size
. there has been studies suggesting that the greater functional surface area occupied by giant cells and larger relative size of giant cells may identify tumors with aggressive behavior .
recently , kruse - loser et al . , also proved that the aggressive variant of cgcg presented a high number of giant cells , an increased mitotic activity , and a high fractional surface area .
however , other studies have not been able to predict the clinical course of cgcgs from known histological or immunohistochemical features .
we reviewed the archival cases of 10 cgcgs from our department which were nonaggressive and non recurrent , the demographical information , location , radiographic features and histopathological features of which are shown in table 1 .
the demographic information , location , radiographic features and histopathological features of 10 nonaggressive cgcgs are as follows the present case showed 2 - 3 giant cells per high power field , which was less compared to that seen in our archival cases .
the connective tissue was minimal , but with a high cellularity and a vesiculated fibroblast population .
the nonaggressive cases of cgcg showed a minimal - moderate cellularity and a non vesiculated fibroblast population .
the vascularity in the present case was minimal , which was not a differentiating factor , as cases in the archives showed a varied vascularity from minimal to marked .
. it may be well - defined or ill - defined and shows variable expansion and destruction of the cortical plate .
the radiological appearance of the lesion is not pathognomonic and may be confused with that of many other lesions of jaws .
the final diagnosis eventually rests on histopathology because the clinical and radiological features are not specific .
cgcg of the jaw usually presents as a painless solitary radiolucent expansion in most of the cases .
rankl ( receptor activator of nuclear factor kb ligand ) present on stromal cells influences the differentiation of giant cells from rank expressing mononuclear cells . amongst all , gct is most difficult to differentiate from cgcg without clinical and histological aids .
histologically , cgcg has a hemorrhagic background with presence of plump bland fibroblast , hemosiderin and fewer giant cells with smaller number of nuclei , which are less uniformly distributed . while in case of gct , giant cells are uniformly scattered with larger number of nuclei and absence of fibroblasts and hemorrhage .
diffuse sheets of large giant cells and polygonal mononuclear cells seen in gct are lacking in cgcg .
cystic areas ( the aneurysmal bone cyst component ) are lesser as compared to gct .
differential diagnosis from brown tumor is based mainly on clinical and laboratory data , as well as age of onset and multiplicity of lesions .
immunohistochemical studies on cgcg have helped to establish the lineage of the cells , but not to predict the aggressiveness of the lesion .
supporting the theory that the multinucleated giant cells are derived from macrophages is the immunoreactive response to muramidase , -1antichymotrypsin , and -1antitrypsin .
aggressive and nonaggressive cgcgs stained for antibodies to cd34 , cd68 , factor xllla , and smooth muscle actin , prolyl 4-hydroxylase , ki-67 , p53 protein , rank , and glucocorticoid receptor alpha have revealed no phenotypic differences between the types .
calcitonin receptor expression , however , has been found to exhibit a statistically significant difference with more expression in the aggressive type .
generally , curettage of well - defined localized lesions is associated with a low rate of recurrence . in extensive lesions with radiographic evidence of perforation of cortex ,
the medical management of cgcg as an adjunct to surgery includes treatment with steroids or calcitonin which inhibits osteoclastic activity .
interferon - alpha appears useful in the management of aggressive cgcg , presumably due to its anti - angiogenic effects .
although extensive literature has been made available to the readers who envisage a keen interest in cgcg of the jaw , clarity to this entity with respect to terminology , behavior and its adjunctive nature to the gct occurring in long bones has rarely been lucid in its understanding . the concomitant presence or initiation of this entity with various other diseases like aneurysmal bone cyst and also its histopathological similarities to diseases associated with hormonal imbalances like
the present case highlights the perplexity in diagnosing cgcgs , which are aggressive in nature due to its close proximity with respect to pathology , behavior and prognosis from gct .
the recurrent nature of the present case and the extensive destruction caused in the hard and soft tissues convinces us the need of exploring the possibilities of the so called true | central giant cell granuloma is a fairly common lesion in the jaws aetiology of which is still completely unknown but thought to be of a reactive process to some unknown stimuli .
it usually arises either peripherally in periodontal ligament , mucoperiosteum , or centrally in the bone .
the histological hallmark for both peripheral and central giant cell granuloma ( cgcg ) is the presence of distinctive multinucleated giant cells ( mgcs ) in a prominent fibrous stroma .
central giant cell granuloma is an uncommon benign proliferative lesion that almost exclusively occurs within the jaw .
eventually , it may become aggressive leading to the expansion and perforation of cortex resulting into mobility and displacement of teeth with root resorption .
the present case focuses on the dilemma and perplexity in diagnosing aggressive cgcgs , due to its close proximity with respect to pathology , behavior and prognosis from giant cell tumors ( gct ) .
central giant cell granuloma persuaded extensive destruction to the hard and soft tissues with high rate of recurrence encourage us the need of exploring the possibilities of giant cell tumors having a definitive presence in the jaws . |
the idea that there may exist a hidden mirror sector of particles and interactions with exactly the same properties as our visible world was suggested long time ago by lee and yang @xcite , and the model with exact parity symmetry interchanging corresponding fields of two sectors was proposed many years later by foot at al . @xcite .
the two sectors communicate with each other only via gravity . a discrete symmetry
@xmath0 interchanging corresponding fields of @xmath1 and @xmath2 , so called mirror parity , guarantees that two particle sectors are described by identical lagrangians , with all coupling constants ( gauge , yukawa , higgs ) having the same pattern . as a consequence
the two sectors should have the same microphysics .
after its first applications to non - baryonic dark matter @xcite , the mirror matter hypothesis has been invoked in many physical and astrophysical questions : large scale structure of the universe @xcite , galactic halo @xcite , machos @xcite , gamma ray bursts @xcite , orthopositronium lifetime @xcite , neutrino physics @xcite , interpretation of dark matter detection experiments @xcite , meteoritic event anomalies @xcite , close - in extrasolar planets @xcite , pioneer spacecraft anomalies @xcite .
if the mirror ( m ) sector exists , then the universe along with the ordinary ( o ) particles should contain their mirror partners , but their densities are not the same in both sectors .
in fact , berezhiani et al .
@xcite showed that the bbn bound on the effective number of extra light neutrinos implies that the m sector has a temperature lower than the o one , that can be naturally achieved in certain inflationary models @xcite .
then , two sectors have different initial conditions , they do not come into thermal equilibrium at later epoch and they evolve independently , maintaining approximately constant the ratio among their temperatures . all the differences with respect to the ordinary world can be described in terms of only two free parameters in the model , @xmath3 and @xmath4 , where @xmath5 ( @xmath6 ) and @xmath7 ( @xmath8 ) are respectively the ordinary ( mirror ) photon temperature and the ordinary ( mirror ) baryon density .
the bounds on the mirror parameters are @xmath9 @xcite and @xmath10 , the first one coming from the bbn limit and the second one from the hypothesis that a relevant fraction of dark matter is made of mirror baryons .
in fact , if @xmath11 , mirror baryons emerge as a possible dark matter candidate ( mbdm ) @xcite ; the peculiar properties of mirror dark matter were discussed in ref . @xcite
the important moments for the structure formation are related to the matter - radiation equality ( mre ) and to the matter - radiation decoupling ( mrd ) epochs .
the mre occurs at the redshift @xmath12 therefore , for @xmath13 it is not altered by the additional relativistic component of the m sector .
the mirror mrd temperature @xmath14 can be calculated following the same lines as in the o one @xcite , and hence @xmath15 so that the mrd in the m sector occurs earlier than in the o one .
moreover , for values @xmath16 , the mirror photons would decouple yet during the radiation dominated period .
this critical value plays an important role in our further considerations , where we distinguish between two cases : @xmath17 and @xmath18 .
the relevant scale for gravitational instabilities is the mirror jeans mass , defined as the minimum scale at which , in the matter dominated epoch , sub - horizon sized perturbations start to grow . in the case
@xmath17 ( where the mirror decoupling happens after the matter - radiation equality ) its maximum value is reached just before the mirror decoupling , and is expressed in terms of the o one as @xmath19 which , for @xmath20 and @xmath21 , means that the jeans mass for the m baryons is lower than for the o ones , with implications for the structure formation process . if , e.g. , @xmath22 and @xmath23 , then @xmath24 .
we can also express the same quantity in terms of @xmath25 , @xmath26 and @xmath27 , in the case that all the dark matter is in the form of mirror baryons , as @xmath28 for the case @xmath29 , the mirror decoupling happens before the matter - radiation equality . in this case
we obtain for the highest value of the jeans mass just before decoupling the expression @xmath30 in case @xmath31 , the expressions ( [ mj_mir_1 ] ) and ( [ mj_mir_2 ] ) , respectively valid for @xmath32 and @xmath33 , are coincident , as we expect . if we consider the differences between the highest mirror jeans mass for the particular values @xmath34 , @xmath31 and @xmath35 , we obtain the following relations : @xmath36 @xmath37 density perturbations in mbdm on scales @xmath38 which enter the horizon at @xmath39 undergo uninterrupted linear growth .
perturbations on scales @xmath40 start instead to oscillate after they enter the horizon , thus delaying their growth till the epoch of m photon decoupling . as occurs for perturbations in the o baryonic sector ,
also the m baryon density fluctuations should undergo the strong collisional silk damping around the time of m recombination , so that the smallest perturbations that survive the dissipation will have the mass @xmath41 ^ 3 ( \beta \ , \omega_b h^2)^{-5/4 } 10^{12}~ m_\odot \;,\ ] ] where @xmath42 for @xmath17 , and @xmath43 for @xmath18 .
for @xmath44 we obtain @xmath45 , a typical galaxy mass .
in order to obtain quantitative predictions we computed numerically the evolution of scalar adiabatic perturbations in a flat universe in which is present a significant fraction of mirror dark matter at the expenses of diminishing the cdm contribution and maintaining constant @xmath46 . we have chosen a `` reference cosmological model '' with the following set of parameters @xcite : @xmath47 .
the dependence of the cmb and lss power spectra on the parameters @xmath48 and @xmath49 is shown in fig .
[ cmblssfig3 ] .
the predicted cmb spectrum is quite strongly dependent on the value of @xmath48 , and it becomes practically indistinguishable from the cdm case for @xmath50 .
however , the effects on the cmb spectrum rather weakly depend on the fraction of mirror baryons . as a result of the oscillations in mbdm perturbation evolution
, one observes oscillations in the lss power spectrum ; their position clearly depends on @xmath48 , while their depth depends on the mirror baryonic density . superimposed to oscillations
one can see the cut - off in the power spectrum due to the aforementioned silk damping . in the same figure our predictions
can be compared with the observational data in order to obtain some general bound on the mirror parameters space . *
the present lss data are not compatible with a scenario where all the dark matter is made of mirror baryons , unless we consider enough small values of @xmath26 : @xmath51 . *
high values of @xmath26 , @xmath52 , can be excluded even for a relatively small amount of mirror baryons .
in fact , we observe relevant effects on lss and cmb power spectra down to values of m baryon density of the order @xmath53 . *
intermediate values of @xmath26 , @xmath54 , can be allowed if the mbdm is a subdominant component of dark matter , @xmath55 . * for small values of @xmath26 , @xmath56 , the mbdm and the cdm scenarios are indistinguishable as concerns the cmb and the linear lss power spectra . in this case , in fact ,
the mirror jeans and silk lengths , which mark region of the spectrum where the effects of mirror baryons are visible , decrease to very low values , which undergo non linear growth from relatively large redshift .
thus , with the current experimental accuracy , we can exclude only models with high @xmath26 and high @xmath57 ; however , there can be many possibilities to disentangle the cosmological scenario of two parallel worlds with the future high precision data concerning the large scale structure , cmb anisotropy , structure of the galaxy halos , gravitational microlensing , oscillation of observable particles into their mirror partners , etc .
i am grateful to my invaluable collaborators zurab berezhiani , denis comelli and francesco villante .
i would like to thank also silvio bonometto , stefano borgani , alfonso cavaliere and nicola vittorio for interesting discussions .
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d 69 , 123510 ( 2004 ) [ hep - ph/0402267 ] . | in the mirror world hypothesis the mirror baryonic component emerges as a possible dark matter candidate . here
we study the behaviour of the mirror dark matter and the differences from the more familiar cdm candidate for structure formation , cosmic microwave background and large scale structure .
we show mirror models for cmb and lss power spectra and compare them with observations , obtaining bounds on the mirror parameter space . |
radio - band observations of absorption systems along the sight - lines to distant quasars provide a powerful probe of the cool atomic and molecular gas at high redshift .
this gas constitutes the reservoir of raw material which forms stars , planets and all other non - diffuse structures in the early universe . as well as giving insight into how the contents of present day galaxies came to be , redshifted 21-cm and oh 18-cm absorption lines
have the potential to be very useful in determining whether the fundamental constants of nature have changed since these large look - back times ( see @xcite and references therein ) .
unfortunately , such absorption is currently rare , with only 76 21-cm absorbers known at @xmath5 , 41 of which are due to intervening systems ( summarised in @xcite ) , with 35 being associated with the quasar / quasar host providing the background illumination ( summarised in @xcite ) .
oh 18-cm absorption is rarer still , with only five systems known @xcite , three of which are intervening and two being associated with the background source .
all of the oh and 80% of detected absorption occurs at @xmath6 .
much of this bias is due to the limited availability of interference free bands at low frequencies , although there are additional effects contributing to lower detection rates at high redshift : for the intervening , systems the 21-cm detection rates ( 61% at @xmath6 cf .
33% at @xmath7 , @xcite ) can be attributed to the geometry effects introduced by a flat expanding universe , causing the coverage of the background flux to be systematically lower at higher redshift @xcite . for associated systems , the rates ( 39% at @xmath6 cf .
17% at @xmath7 ) are biased by the traditional optical selection of targets , where only the most ultra - violet luminous sources are known at high redshift , since the intense uv flux from the near - by active galactic nucleus ionises / excites the cool gas beyond detection @xcite .
although both of these effects are present in some cases at @xmath6 , although they are always present for the high redshift sources .
optical selection effects further compound the detection of oh absorption in that , despite much searching of objects in the millimetre - band , where four of the five oh absorbers were originally discovered , millimetre - wave absorption has yet to be found in an optically selected target ( see @xcite ) .
@xcite suggest that this is due to the optical brightness of these objects selecting against the dustier , and thus most molecular friendly absorbers .
this is demonstrated through the optically selected damped lyman-@xmath8 absorption systems ( dlas ) having optical near infrared colours of @xmath9 and molecular fractions of @xmath10 , whereas the radio absorbers have @xmath11 and @xmath12 ( see figure 3 of @xcite ) .
this is strong evidence that the background quasar light is reddened by the dust in the foreground absorber , which protects the molecular gas from the harsh uv environment .
thus , in order to increase the number of redshifted oh ( and ) absorbers known , we should target the reddest objects in the gravitational lens intervening pks 0132097 @xcite : with the detection of 21-cm absorption @xcite and an optical near - infrared colour of @xmath13 along this sight - line @xcite , this was a prime target . on this basis , we ourselves attempted to detect oh with both the giant metrewave radio telescope ( gmrt ) and the westerbork synthesis radio telescope in february 2005 .
however , severe rfi at 945 mhz ruined both observations . ] .
however , due to their very faintness , optical spectra are not generally available and so we do not have a redshift to which to tune the telescope .
we have therefore embarked on a programme of wide - band ( 200 & 800 mhz ) spectral scans of very red ( @xmath14 ) radio - loud objects with the green bank telescope ( gbt ) in search of the dust and molecular gas responsible for the obscuration . in this letter
we report the detection of very strong 21-cm absorption at @xmath2 towards the @xmath15 quasar mg j0414 + 0534 ( 4c+05.19 ) , where we have previously detected 21-cm in the @xmath1 gravitational lens @xcite . with an optical near - infrared colour of @xmath16 ,
this is the reddest of our targets , and , although 21-cm has also been detected in the lens , as well as in the host galaxy @xcite , oh remains undetected at either of these three redshifts .
as mentioned above , all of our targets were selected on the basis of their large optical near - infrared colours ( @xmath14 ) and high radio fluxes ( @xmath17 jy ) .
being a database of bright and generally compact objects , with comprehensive optical photometry @xcite , these were taken from the parkes half - jansky flat - spectrum sample ( phfs , @xcite ) , which , with the above conditions , gave five sources which could be scanned for both and oh by the gbt .
however , given the very wide band - widths required for the full spectral scans , much of the data are subject to severe radio frequency interference ( rfi ) , with only limited parts of the band being useful ( tanna et al .
, in prep ) .
nevertheless , we are able to obtain enough useful data on mg j0414 + 0534 to reveal a clear , strong detection of neutral hydrogen . the 0.911.23 ghz range of the j0414 + 0534 observations were performed on 23 january 2007 using the pf2 receiver and the autocorrelation spectrometer over a 200 mhz wide bandpass ( with 16384 lags ) , centred on 1.0 ghz in two orthogonal linear polarisations .
this band was observed for a total of two hours in 5 min position - switched scans , and the removal rfi affected scans left 44 minutes of good data , with a mean system temperature of @xmath18 k and an r.m.s .
noise level of @xmath19 mjy per 3.56 ( at 1030 mhz ) channel in the clear parts of the bandpass .
mhz towards j0414 + 0534 in each of the two orthogonal linear polarisations .
the data are shown at the observed 12.207 khz channel spacing , which gives 3.56 at 1030 mhz .
the flux density is found to be 2.21 jy at 1.03 ghz , cf .
the 2.12 jy at 1.4 ghz @xcite . ]
the data were calibrated , flagged and averaged using the gbtidl package and , as seen in each of the polarisations , an absorption feature was detected close to 1030 mhz ( fig . [ pols ] ) . due to the structure of the line and the strength of the main component ( a velocity integrated optical depth of @xmath20 ) , we believe that the feature is due to 21-cm absorption at a redshift of @xmath21 .
in each polarisation ( fig . [ pols ] )
it is clear that the absorption is comprised of several components and in fig .
[ gauss ] we show the gaussian fits to the profile and summarise these in table [ fits ] . ) .
the flux scale is relative to 2.21 jy and the velocity offset is relative to the central observing frequency of 1.000 ghz . as fig .
[ pols ] , the velocity resolution is 3.56 . ] [ cols="^,^,^,^,^,^,^,^,^",options="header " , ] a single gaussian fit to the main component gives @xmath22 , i.e. @xmath23 for the redshift of the absorber .
this , in addition to the separate gaussian fits to the blue and redshifted features ( see below ) , gives a velocity integrated optical depth of @xmath24 .
this is the strongest intervening 21-cm absorber yet found ( see table 1 of @xcite and figure 12 of @xcite ) , the next being at @xmath25 towards b0235 + 164 with @xmath26 @xcite .
the line strength gives a neutral hydrogen column density of @xmath27 , where @xmath28 is the spin temperature of the gas and @xmath29 the coverage of the background flux by the absorber .
given that @xmath30 k is the minimum typical value of this degeneracy ( see @xcite ) , it is clear that the neutral hydrogen column density in this absorber is large , @xmath31 , which is in the top 2% of sloan digital sky survey data release 5 dlas @xcite .
the largest is @xmath32 , a value which is exceeded by the absorber for @xmath4 k .
in addition to the main component , there is a strong red - shifted and a weaker blue - shifted component , offset at @xmath33 and @xmath34 , respectively .
these features have absorption line strengths which are @xmath35% and @xmath36% of the main profile ( @xmath37 ) , the redshifted feature being as strong as any of those in the main profile ( table [ fits ] ) .
we interpret these as being due to outflows from the nucleus of the galaxy , which contain a significant portion of the absorbing gas .
this is reminiscent of the circinus galaxy , a near - by seyfert in which the outflowing molecular gas mass is comparable with that in the disk @xcite . if the disk of the galaxy intervenes most of the background flux , as may be evident from the large optical depth , the relatively narrow full - width half maximum of the main profile ( fwhm@xmath38 ) may suggest a low to intermediate inclination for the galactic disk .
thus , this may have an axis direction similar to that of the outflow , which we believe is directed close to the line - of - sight , since it must intercept much of the flux from j0414 + 0534 . at 1.4 ghz @xcite , which is 26 kpc at @xmath2 ( @xmath39 km s@xmath40 mpc@xmath40 , @xmath41 and @xmath42 ) .
] however , this is not a necessity , as the galactic disk ( in which the absorption occurs ) need not be coplanar with the circumnuclear torus , invoked by unified schemes of active galactic nuclei , which collimates the outflow ( @xcite and references therein ) .
since the purpose of our spectral scans is to find the intervening molecular gas responsible for the reddening of the background quasar , the frequencies covering the four 18 cm @xmath43 oh lines were observed simultaneously in separate ifs .
given the redshift of the 21-cm absorption , we expect the oh transitions to occur at 1169.15 ( 1612 ) , 1207.71 ( 1665 ) , 1209.13 ( 1667 ) and 1247.69 mhz ( 1720 mhz ) .
examining the data which contain these frequencies ( fig .
[ oh - spectra ] ) , we see that there may indeed be two features coincident with the 1665 ( @xmath44 ) and 1667 mhz ( @xmath45 ) transitions ( oh1667 panel ) , although , even after removal of the worst rfi , the bandpass is somewhat bumpy . from a gaussian fit to the higher frequency feature , we obtain a centroid of @xmath46 mhz , which is where the @xmath45 transition would occur at a redshift of @xmath47 implying that the @xmath44 should be redshifted to @xmath48 mhz .
however , this is observed at @xmath49 , which in conjunction with the fact that @xmath50 is out of the range of any of the features ( table [ fits ] ) , leads us to conclude that these are artifacts of an unstable bandpass .
since the 1665 mhz band is the cleanest over the 21-cm redshift , we use this transition to obtain an optical depth limit .
@xcite found a correlation between the and oh profile widths for the five known redshifted oh absorbers and so we resample the r.m.s .
noise level of 1.8 mjy per 10 to the fwhm of the main 21-cm absorption profile .
this gives a @xmath51 limit of @xmath52 per 86 or @xmath53 , where @xmath54 is the excitation temperature of the gas .
normalising this by the line strength of the main 21-cm profile gives @xmath55 , which is five times more sensitive than our previous limit in the @xmath1 gravitational lens ( fig .
[ ohoverh ] ) .
if the molecular abundance is correlated with the red colour of the background quasar @xcite ) , it is apparent that none of the two known intervening 21-cm absorbing systems towards j0414 + 0534 is the cause of the reddening .
furthermore , from oh observations at the host galaxy redshift ( curran et al .
, in prep . )
, we have obtained a limit of @xmath56 per 5 from the @xmath57 transition .
rescaling this to the fwhm of @xmath58 for the 21-cm profile @xcite , gives @xmath59 , or a normalised line strength of @xmath60 , which may not rule out strong oh absorption in the host galaxy ( fig .
[ ohoverh ] ) .
note that the low hcn abundance ( @xmath61 @xmath62 , for @xmath63 k ) found by @xcite may not rule out a large molecular abundance either , on the basis that @xcite detect strong oh , but no hco@xmath64 , absorption towards pks 0132097 , which @xcite suggest is due to differences in the coverage of the millimetre and decimetre - wave emission .
given that three absorption systems are now known towards this source , however , it is feasible that the red colour of the background quasar arises from an accumulation of systems , rather than a single dusty intervening galaxy .
having discovered the absorption , the question of its origin arises . there have been a number of optical / near - infrared studies of j0414 + 0534 @xcite , and these show , in addition to the four quasar images ( a1 , a2 , b & c ) and the lensing galaxy , a feature often referred to as `` object x '' ( fig .
[ lens ] ) .
it is located about 1 arc - sec west of component b , giving impact parameters of between 515 kpc ( for @xmath2 ) and 825 kpc ( for @xmath1 ) to the four quasar images .
hst photometry @xcite gives @xmath65 and @xmath66 , thus having a different colour to the quasar images , while probably being slightly redder than the lensing galaxy .
we note that the spectrum of @xcite shows tantalising evidence of peaks approximately where the @xmath67 doublet would be located for the absorption redshift of @xmath68 ( observed wavelengths of @xmath69 and @xmath70 ) . the slit position , as indicated in their figure 1 ,
would indeed lie directly across object x and large emission line fluxes would be expected from an agn or gas - rich galaxy undergoing rapid star - formation , either of which are consistent with the observation of rapid outflows of in each direction .
as part of an ongoing project , scanning the entire redshift space towards highly reddened radio sources , in search for the object responsible for the obscuration of the optical light , we have detected a second intervening 21-cm absorber at @xmath2 towards the @xmath15 quasar mg j0414 + 0534 .
the other intervening absorber arises in the @xmath1 gravitational lens @xcite and , combined with the absorption found at the host redshift @xcite , gives a total of three absorbers so far detected along this sight - line .
although we can not determine the @xmath71 degeneracy for any of the three 21-cm absorbers , thus deriving the column densities , the 21-cm line strength in this new absorber is by far the strongest detected along this sight - line , being four times stronger than in the host galaxy [ @xmath72 ] and 19 times stronger than in the lens [ @xmath73 ] .
in fact , the strongest intervening 21-cm absorber found to date . despite the absorption strength and the very red colour of this source ( @xmath16 ) ,
oh remains undetected to very strong limits [ @xmath55 ] , inferring that this new absorber is not the primary cause of the red colour .
oh is also undetected in the lens and the host galaxy , although the latter is to relatively weak limits not allowing us to rule out that this is where much of the reddening occurs .
we suggest that the absorption may be associated with the feature known as object x in the optical field of j0414 + 0534 : this could be spatially coincident with the spectrum of @xcite , of which the @xmath69 and @xmath70 features are consistent with the expected wavelengths for the doublet at the redshift of the 21-cm absorption feature .
not being a companion of the lensing galaxy would have implications for the current lens models ( e.g. @xcite ) .
this is the fourth only of the ( now ) 42 known redshifted intervening 21-cm absorbers , which have been _ discovered _ through 21-cm absorption , the others being at @xmath75 towards b0809 + 483 @xcite , @xmath76 towards b1328 + 307 @xcite and @xmath77 towards b2351 + 456 @xcite .
the vast majority have been found by tuning the receiver to a frequency based upon the redshift of an a priori detected absorber ( mgii or lyman- ) .
being optically selected , this traditional method biases against the more dust obscured systems and the discovery of two intervening 21-cm absorbers from spectral scans towards j0414 + 0534 , suggests that future surveys with square kilometre array may uncover a large population of faint , dusty high redshift galaxies .
we would like to thank jeremy darling who provided fig . [ lens ] .
this research has made use of the nasa / ipac extragalactic database ( ned ) which is operated by the jet propulsion laboratory , california institute of technology , under contract with the national aeronautics and space administration .
this research has also made use of nasa s astrophysics data system bibliographic services . c. s. , falco e. e. , impey c. d. , lhar j. , mcleod b. a. , rix h .- w . , 1999 , in holt s. ,
smith e. , eds , after the dark ages : when galaxies were young ( the universe at @xmath78 ) vol .
470 of american institute of physics conference series , results from the castles survey of gravitational lenses . | we report the detection of a third 21-cm absorber in the sight - line towards the @xmath0 quasar mg j0414 + 0534 ( 4c+05.19 ) .
in addition to the absorption at the host redshift and in the @xmath1 gravitational lens , we find , through a decimetre - wave spectral scan towards this source , strong absorption at @xmath2 .
we believe this may be associated with `` object x '' , an additional feature apparent in the field of the lensing galaxy and lensed images , on the basis of its close proximity to the quasar images and the possible detection of the doublet in a published optical spectrum .
if real , the strength of the emission would suggest the presence of an active galactic nucleus , or a gas - rich galaxy undergoing rapid star formation , either of which is consistent with the strong outflows apparent in the 21-cm spectrum .
although this is the strongest intervening 21-cm absorber yet found ( a column density of @xmath3 , for a modest @xmath4 k ) , simultaneous observations failed to detect any of the 18-cm oh lines at the 21-cm redshift .
this suggests that , as for the lensing galaxy , this is not the primary location of the intervening material responsible for the very red colour of mg j0414 + 0534 .
[ firstpage ] galaxies : active quasars : absorption lines radio lines : galaxies galaxies : high redshift galaxies : ism galaxies : individual ( mg j0414 + 0534 ) |
Ah Denmark, what a country. If any society breathes the spirit of liberty, this is it.
It was only a few weeks ago that I was in Copenhagen for some international conference, and as ever I rose early and went for a run. As I passed through some yuppie zone of warehouse conversions and posh restaurants I saw to my amazement that the Danes had also got up early for exercise – and they were diving stark naked into the bracing waters of the harbour. And I thought to myself – that’s the Danes for you; that’s the spirit of Viking individualism. I mean, we have a climate warmer than Denmark; but even so, would you expect to see Brits disrobing and plunging into the waters of Canary Wharf, or even Greenwich?... ||||| BBC Radio 4 Today ಪರಿಶೀಲಿಸಿದ ಖಾತೆ @BBCr4today
. @ AlistairBurtUK says he "would never have made" the comment about burqas which @ BorisJohnson is being criticised for: "I think there is a degree of offence in that... the point he was trying to make was the government will not enforce any clothing restriction" # r4today ||||| Former British Foreign Secretary Boris Johnson is facing a Conservative Party investigation over a column comparing women who wear face-covering veils to mailboxes and bank robbers.
The party has received complaints that the comments breach its code of conduct, and under Conservative rules they must be investigated by an independent panel. Possible penalties include expulsion from the party.
The party confirmed it had received complaints but declined to give details Thursday, saying that the process is confidential.
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The Conservative code of conduct says members should “lead by example to encourage and foster respect and tolerance.”
Johnson, who quit the government last month in a dispute over Brexit, wrote in the Daily Telegraph this week that it was “absolutely ridiculous that people should choose to go around looking like letter boxes.” He said he opposed banning burqas and other face-covering garments worn by some Muslim women, but referred to a woman wearing the attire as “looking like a bank robber.”
Johnson’s comments were criticized by Muslim groups and politicians including Prime Minister Theresa May, who urged Johnson to apologize. He has not said sorry.
Tousle-headed Johnson is one of Britain’s best-known politicians, a popular but divisive figure known for Latin quips and verbal blunders that have included calling Papua New Guineans cannibals and accusing people in Liverpool of “wallowing” in victimhood.
Critics claim Johnson is using the burqa comments to boost his appeal among right-wing members of the party. Many expect May to face a leadership challenge soon if faltering Brexit negotiations with the European Union don’t improve — and Johnson is likely to be a contender to replace her.
He is popular with the pro-Brexit wing of the Conservative Party, which is deeply divided over its attitude to the EU. His Brexiteer credentials were bolstered when he resigned as foreign secretary in July, accusing May of killing “the Brexit dream” with her plan to seek close economic ties with the bloc after Brexit next year. ||||| Tory peer says Boris Johnson should lose the whip as he continues to defy order to apologise
Pressure on Boris Johnson over his controversial remarks about women in burqas is mounting across the Conservative party a day after the former foreign secretary was rebuked by Theresa May.
A Conservative peer said Johnson should have the whip withdrawn, while a cabinet member called on him to retract his words and use language more carefully, as the row started by the man seen as a possible party leader continued into a third day.
The prime minister criticised Johnson over his claim that Muslim women in burqas resemble letterboxes and bank robbers, urging him to apologise after he defied an order to do so by Tory chiefs.
She said she agreed with the Conservative party chairman, Brandon Lewis, that Johnson should say sorry for his remarks, which she acknowledged had caused offence in the Muslim community.
May urged people to be “very careful” about the language they used to discuss sensitive issues such as women wearing the burqa, but stopped short of saying Johnson’s comments were Islamophobic or that he should lose the Tory whip, meaning he would no longer represent the party in parliament.
All apologies: the many times Boris Johnson has been told to say sorry Read more
Following her intervention, Lord Sheikh, the founder of the Conservative Muslim Forum, set up to encourage British Muslims to get involved in political life, called for the party to withdraw the whip from Johnson.
“Take the whip from him. Why not? He’s not a super human being, he’s a member of the party. The party chairman, the prime minister has the right to take the whip … that’s the thing I’d like to see,” he told the BBC’s Newsnight.
Further pressure was put on the former foreign secretary by the culture secretary, Jeremy Wright, who said Johnson should have chosen his language more carefully.
“When you are discussing a subject such as this, then I think describing it as people looking like letterboxes isn’t helpful. I think we should all choose our language with care,” he told the BBC’s Today programme on Wednesday.
Wright said he was “sure on reflection” that Johnson would want to reconsider the language he had used, but he sidestepped questions over whether the MP should have the whip removed, saying: “That’s not a decision for me.”
Eric Pickles, a former Tory chairman, told Today: “The very sensible thing would be for him to apologise.”
The peer and former communities secretary said he did not understand Johnson’s motives and claimed his comments had closed down the debate on face veils. “There are tensions now that exist within the community, a degree of hatred out there that I’ve not witnessed for a good few years,” he said.
It came as Conservative party chiefs sought to dampen the Islamophobia row that has re-erupted since Johnson’s remarks in response to Denmark’s introduction of a ban on burqas in public places.
Sidestepping the question of whether the former foreign secretary was Islamophobic, May had said: “I have said it’s very clear that anybody who is talking about this needs to think very carefully about the language that they use and the impact that language has had on people, and it is clear that the language that Boris used has offended people.”
May was emphatic that women in the UK ought to be able to choose freely what they wanted to wear. “What is important is do we believe that people have the right to practise their religion, should have the right to choose – in the case of women, and the burqa and the niqab – how they dress,” she said.
“It is absolutely that women should be able to choose how they dress and shouldn’t be told how to do it by other people. And I believe that all of us when we talk about these issues should be very careful about the language that we use.”
May also said: “Some of the terms that Boris used in describing people’s appearance obviously have offended people and so I agree with Brandon Lewis.”
On Tuesday night, Johnson – who is believed to be on holiday in Europe – continued to defy via Twitter Lewis’s order to apologise for his remarks. He is understood to view the instruction as an attempt to shut down debate on a difficult issue that should be tackled head-on.
Brandon Lewis (@BrandonLewis) I agree with @AlistairBurtUK. I have asked @BorisJohnson to apologise. https://t.co/RFExXO4LOR
However, Johnson faced criticism from Tory politicians and Muslim groups for his comments, which some claimed were designed to pander to rightwing voters to bolster his future leadership chances. He came under fire recently for meeting the former Donald Trump adviser Steve Bannon.
The former Tory chairman Sayeeda Warsi, who has accused Johnson of “dog-whistle” Islamophobia, told Sky News on Tuesday: “Boris knew what he was doing when he made those comments, when he chose to use this very specific language he would know the impact and the effect it would have.”
“I think Boris is making yet another leadership bid and he will do and say whatever needs to be done to make that as successful as he can … I sincerely hope that he doesn’t continue to use Muslim women as a convenient political football to try and increase his poll ratings.”
The Conservative party has been accused of a lack of action on tackling Islamophobia in its ranks after Lewis said in June that diversity training would be offered to all members, and local associations would report back on how complaints were handled.
Before May’s intervention, a number of Tory MPs had criticised Johnson’s remarks. Alistair Burt, the minister for the Middle East, who worked under him, described them as offensive and said he would never have said anything similar.
He told the BBC that Johnson had been defending Muslim women’s right to wear the religious dress. But he added: “I would never have made such a comment. I think there is a degree of offence in that, absolutely right.”
Fiyaz Mughal, the founder of Tell Mama, which campaigns against anti-Muslim violence, said Johnson’s comments amounted to Islamophobia.
“These are the kind of comments we have seen that have been made by extremist far-right groups and people who have been maliciously attacking Muslims, so clearly it does fit that bracket,” he said.
The shadow equalities minister, Naz Shah, said: “Boris Johnson’s comments were not just offensive, they were Islamophobic, but the prime minister is in denial. An apology is not enough, she needs to order an independent inquiry into Islamophobia in her party, as requested by the Muslim community, and take action against him.”
Shazia Awan-Scully, a former Tory parliamentary candidate, accused Johnson of “pandering to the extreme right”, comparing his comments to Enoch Powell’s “rivers of blood” speech, and said he should be sacked.
“If you cast your mind back 50 years to when Enoch Powell gave his rivers of blood speech, he was sacked from the shadow cabinet immediately,” she told Newsnight.
In his column for the Telegraph on Monday, Johnson said Muslim women wearing burqas looked like bank robbers, and schools and universities should be entitled to tell students to remove them.
He said it was “absolutely ridiculous” that wearers should “go around looking like letterboxes”, and he would expect his constituents to remove them in his MP’s surgery.
However, Johnson said he did not support a blanket ban on the face veil in the UK. “You risk turning people into martyrs, and you risk a general crackdown on any public symbols of religious affiliation, and you may simply make the problem worse,” he wrote. ||||| Image copyright Getty Images Image caption Protesters gathered in Uxbridge, Mr Johnson's constituency, on Thursday
Boris Johnson is facing a possible investigation into breaches of the Conservative Party code of conduct.
The party has received dozens of complaints about the ex-foreign secretary's comments about Muslim women wearing burkas.
The complaints will be looked at by an independent panel which could refer Mr Johnson to the party's board, which has the power to expel him.
The party declined to comment on the details of the investigation.
A Conservative Party spokesman said: "The code of conduct process is strictly confidential." A source close to Mr Johnson offered no comment.
Meanwhile more than 30 protesters have gathered in Mr Johnson's constituency of Uxbridge, calling for his resignation.
Mr Johnson has rejected calls to apologise for saying people wearing burkas looked like "letter boxes" or "bank robbers", in a Daily Telegraph column in which he also argued against a ban on full-face veils.
Critics have accused him of stoking Islamophobia to boost his Tory leadership ambitions but his supporters have said he was speaking up for "liberal values".
It comes as a watchdog which advises ex-ministers on taking new jobs ruled that Mr Johnson broke ministerial rules by taking up his weekly column at the Telegraph without consulting it first.
The Conservative Party has been accused of not doing enough to tackle anti-Muslim prejudice in its ranks, despite an initiative to boost tolerance and diversity.
The party's code of conduct states that Tory officials and elected representatives must "lead by example to encourage and foster respect and tolerance" and not "use their position to bully, abuse, victimise, harass or unlawfully discriminate against others".
The independent panel will decide whether to refer Mr Johnson to the party's board. Possible action includes suspension of membership or expulsion from the party among other, lesser sanctions.
Image copyright PA Image caption Cressida Dick: Johnson did not commit an offence
Conservative Party chairman Brandon Lewis and leader Theresa May have both called on Mr Johnson to apologise for his comments.
The founder of the Conservative Muslim Forum, Lord Sheikh, has written to Mr Lewis demanding "serious action", while former attorney general Dominic Grieve said he would quit the party if Mr Johnson became prime minister.
A hundred Muslim women who wear the niqab or burka have signed a letter to Mr Lewis, calling on him to withdraw the Conservative whip from Mr Johnson and launch an independent inquiry into Islamophobia in the party.
"We are not forced to make these clothing choices, nor are we oppressed," the women write in their letter, which has been issued to the media by the Muslim Council of Britain.
They say Mr Johnson's words will "inflame tensions in a way that makes it easier for bigots to justify hate crimes against us".
Azmat Parveen, who attended the protest in Uxbridge on Thursday, called Mr Johnson's comments "painful".
"This is a way of life, I want to choose this way and somebody remarks on it, I can't bear it, it is very, very rude," the 68-year-old said.
"I want him to leave his seat."
'Legitimate debate'
Earlier, Metropolitan Police Commissioner Cressida Dick said that while many have found Mr Johnson's remarks offensive, officers had decided that he did not commit an offence.
She also confirmed that police have not received any criminal complaint against the former foreign secretary.
"I also know that many other people believe strongly that in the whole of the article, what Mr Johnson appears to have been attempting to do was to say that there shouldn't be a ban and that he was engaging in a legitimate debate," she added.
Asked what she made of the language used by the ex-cabinet minister, Ms Dick told the BBC Asian Network: "Some people have clearly found it offensive.
"I spoke last night to my very experienced officers who deal with hate crime and, although we have not yet received any allegation of such a crime, I can tell you that my preliminary view having spoken to them is that what Mr Johnson said would not reach the bar for a criminal offence. He did not commit a criminal offence."
She added: "I am proud to police in a liberal democracy in which people have the right to express their opinions.
"What Mr Johnson said, if it is not criminal, is a matter for Mr Johnson and his friends and colleagues and indeed for the Conservative Party."
The police and Crown Prosecution Service define a hate crime as "any criminal offence which is perceived by the victim or any other person, to be motivated by hostility or prejudice, based on a person's disability or perceived disability; race or perceived race; or religion or perceived religion; or sexual orientation or perceived sexual orientation or transgender identity or perceived transgender identity". | – Former British foreign secretary Boris Johnson is in hot water—and at risk of losing his status as Conservative Party whip—over his comments about burkas. In a Telegraph op-ed, Johnson argued the face-covering veil shouldn't be banned in Britain as it is in Denmark, but had unkind words for female wearers. It's "absolutely ridiculous that people should choose to go around looking like letter boxes … looking like a bank robber," Johnson wrote, per the Globe and Mail. After dozens of complaints, an independent panel is investigating whether his comments violated the Conservative Party's code of conduct, which says MPs should "foster respect and tolerance" and avoid using their position "to bully, abuse, victimize, harass or unlawfully discriminate against others," reports the BBC. Though she avoided describing the comments as Islamophobic, Prime Minister Theresa May was among the first to rebuke Johnson for language that "offended people." She's called on him to apologize, as has party chairman Brandon Lewis, among others. Johnson, believed to be vacationing in Europe, has yet to do so. Some suggest that's because the possible candidate for future party leader meant to appeal to right-wing voters. "I sincerely hope that he doesn't continue to use Muslim women as a convenient political football to try and increase his poll ratings," former Tory chairman Sayeeda Warsi tells the Guardian. Meanwhile, the founder of the Conservative Muslim Forum tells the BBC, "the party chairman, the prime minister has the right to take the whip … that's the thing I'd like to see." |
A man with a history of drunken driving charges was arrested in a fatal crash near Salem that killed a mother and her four small children, Oregon State Police said.
Authorities lodged Favian Garcia, 27, in the Marion County Jail Monday morning on suspicion of five counts of manslaughter, felony DUII, reckless driving and driving with a suspended license, said Lt. Cari Boyd, an Oregon State police spokeswoman.
Court records show Garcia was convicted of driving under the influence of intoxicants in 2011 and arrested on suspicion of the same crime in July of this year. Police said the Gervais man had multiple outstanding warrants when he was detained.
Garcia was driving on Highway 99E north of Salem Sunday when his Land Rover slammed head-on into a Buick Century driven by Lisette Medrano-Perez of Molalla around 4:30 p.m., police said.
The 25-year-old mother was in the car with her children, an 8-year-old boy, a 6-year-old boy, a 4-year-old girl and a 2-year-old girl.
All five family members died at the scene, police said. Garcia was taken to a hospital and treated for minor injuries.
"Those were completely innocent children," said Boyd. "There are just no words to explain what happened."
The last accident when five or more people were killed in a crash involving two cars was in 2012. That same year a bus crash was even deadlier.
A database maintained by The Oregonian/OregonLive tracks crashes with five or more fatalities.
-- Shane Dixon Kavanaugh
skavanaugh@oregonian.com
503-294-7632 II @shanedkavanaugh
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Save ||||| SALEM, Ore. (KOIN) — A young mother and 4 children were killed in a head-on crash caused, police say, by a reckless driver under the influence of intoxicants.
Lizette Medrano-Perez, 25, and 4 children — Ivan Ricardo, 8, and Andrus, 6, and girls Dayanara, 4, and Angelina, 2 — died when their Buick Century was hit by a Land Rover driven by Favian R. Garcia.
The 3 older children were Medrano’s own. She was also the temporary legal guardian for her niece Angelina.
The crash happened around 4:40 p.m. Sunday about a mile north of Salem on Hwy 99E near Nevada Street. Investigators said the Land Rover was headed north and was coming around a corner in the road when the crash happened.
All 5 people died at the scene.
Garcia, 27, sustained minor injuries. Officers arrested him and charged him with 5 counts of manslaughter I, felony driving while under the influence of intoxicants, reckless driving, misdemeanor driving while suspended and outstanding unrelated Marion County Warrants.
He’s expected to appear in court on Tuesday.
KOIN 6 News checked his record and found Garcia has had 2 previous DUII charges, including one just 2 months ago.
“To see the sadness in people’s eyes knowing their family members aren’t coming back because somebody made a bad choice is just one of the worst parts about our job,” said OSP Trooper Bob Charpentier.
The Oregon State Police said they’re pouring resources into this investigation to make sure they do a flawless job. Four different accident reconstruction teams are involved to help put together a really clear picture of what exactly happened.
Family and friends are mourning the loss of the young family. Medrano-Perez’s friend Amanda LaFollette sent KOIN the following statement:
She was a beautiful person, I don’t think in the almost year I’ve known her that I’ve seen her angry, or shed a single tear. She worked hard for her children those where her pride and joy, she would do anything for them. She went through some hard times and struggled with worrying about her mother’s health but you wouldn’t notice it because in front of her fears and pain always stood a smile of gold. She loved her family more than life itself and would do anything for them, she always made sure her kids had all their needs and would often times stop what she was doing to be a shoulder for her friends, this truly is one of the hardest and most tragic incidents. She will be truly missed by so many!”
Any crash witnesses who have not spoken to police are asked to call 800.452.7888.
There is a GoFundMe to help cover funeral costs. ||||| A Woodburn man is facing manslaughter and drunk driving charges after police say he crashed head-on with another car, killing a Molalla mother and her four children Sunday on Highway 99E.
Investigators say Favian Garcia, 27, was at the wheel of a black SUV on Highway 99E when about 4:30 p.m. he crashed into the victim's sedan on a curve at NE Nevada Street.
READ MORE: Family heartbroken after 5 relatives, including 4 kids, killed in tragic crash
On Monday morning, Garcia was booked in the Marion County Jail on five counts of first-degree manslaughter, felony while driving under the influence of intoxicants, reckless driving, misdemeanor driving while suspended, and outstanding unrelated Marion County warrants.
Court records show Garcia was arrested for drunk driving and hit-and-run on July 2. He was released from jail in August, but had a warrant out for his arrest when he didn’t show up for court.
Judy Harley lives near that July 2 crash site in Woodburn. When she learned Garcia is now charged in Sunday's crash, she wondered if enough is being done to keep suspects in dangerous driving crashes behind bars.
“It doesn't sound like it, does it? Yeah, yeah it's really sad. A woman and four children? Four children. It was five of them. That's terrible,” she said.
Garcia was also charged with drunk driving in 2011, according to his record.
He was also arrested over and over again for not showing up for court in that case, as well as driving while suspended.
Medrano-Perez and her four children in the vehicle were found dead at the scene of the crash. Her children included an 8-year-old boy, a 6-year-old boy, a 4-year-old girl and a 2-year-old girl.
Oregon State Police say one of the children killed was not Medrano-Perez's child by birth, but she was the child's legal guardian. She had filed paperwork to officially adopt the child next week.
Garcia had minor injuries and was transported to a local area hospital, Oregon State Police said. He is expected to make his first court appearance on manslaughter charges on Tuesday.
Anyone who witnessed the crash should call Oregon State Police at 1-800-452-7888. | – A man arrested for drunk driving and hit-and-run in July killed a woman and four children in a horrific head-on crash on Sunday, Oregon State Police say. Lizette Medrano-Perez, 25, and an 8-year-old boy, a 6-year-old boy, a 4-year-old girl, and a 2-year-old girl were killed when a Land Rover driven by 27-year-old Favian Garcia slammed into their Buick Century a mile north of Salem, KATU reports. "Those were completely innocent children," says police spokeswoman Lt. Cari Boyd. "There are just no words to explain what happened." Garcia was released from jail in August but a warrant for his arrest was later issued when he failed to show up for court. Records show he was also charged with drunk driving in 2011. The crash was Oregon's deadliest since a tour bus crash killed nine people in 2012, the Oregonian reports. Garcia, who was hospitalized after receiving minor injuries in the accident, was booked into jail Monday on five counts of manslaughter, felony driving under the influence of intoxicants, reckless driving, and driving with a suspended license. The three oldest children were Medrano-Perez's and she was the legal guardian of the youngest girl, her niece. "To see the sadness in people's eyes knowing their family members aren't coming back because somebody made a bad choice is just one of the worst parts about our job," OSP Trooper Bob Charpentier tells KOIN. |
290 (106 Congress) is repealed.
(d) Expiration.--
(1) Gramm-rudman-hollings.--Section 275(b) of the Balanced
Budget and Emergency Deficit Control Act of 1985 (2 U.S.C. 900
note) is amended--
(A) by striking ``2002'' and inserting ``2007'';
and
(B) by striking ``2006'' and inserting ``2011''.
(2) Congressional budget act.--Section 904(e) of the
Congressional Budget Act of 1974 (2 U.S.C. 621 note) is amended
by striking ``2002'' and inserting ``2007''.
SEC. 3. EXTENSION OF PAY-AS-YOU-GO REQUIREMENT.
Section 252 of the Balanced Budget and Emergency Deficit Control
Act of 1985 (2 U.S.C. 902) is amended --
(1) in subsections (a) and (b)(1), by striking ``enacted
before October 1, 2002,'' and inserting ``enacted before
October 1, 2007''; and
(2) in subsection (b) by inserting at the end thereof the
following:
``(3) Exception.--Notwithstanding any other provision of
law, there shall be no sequestration under this section for any
fiscal year in which a surplus exists (as measured in
conformance with section 13301 of the Budget Enforcement Act of
1990).''.
SEC. 4. POINT OF ORDER TO REQUIRE COMPLIANCE WITH THE DISCRETIONARY
SPENDING LIMITS AND PAY-AS-YOU-GO.
Section 312(b) of the Congressional Budget Act of 1974 (2 U.S.C.
643(b)) is amended to read as follows:
``(b) Discretionary Spending Limit And Pay-As-You-Go Point of Order
in the Senate.--
``(1) In general.--Except as otherwise provided in
paragraph (6), it shall not be in order in the Senate to
consider any bill or resolution or any separate provision of a
bill or resolution (or amendment, motion, or conference report
on that bill or resolution) that would--
``(A) exceed any of the discretionary spending
limits set forth in section 251(c) of the Balanced
Budget and Emergency Deficit Control Act of 1985 or any
suballocation of such limits among subcommittees under
section 302(b); or
``(B) for direct spending or revenue legislation,
would cause or increase a deficit (as measured in
conformance with section 13301 of the Budget
Enforcement Act of 1990) for any one of the following
three applicable time periods:
``(i) the first year covered by the most
recently adopted concurrent resolution on the
budget;
``(ii) the period of the first 5 fiscal
years covered by the most recently adopted
concurrent resolution on the budget; or
``(iii) the period of the 5 fiscal years
following the first five fiscal years covered
in the most recently adopted concurrent
resolution on the budget.
``(2) Budget resolutions.--Except as otherwise provided in
paragraph (6), it shall not be in order in the Senate to
consider any concurrent resolution on the budget (or amendment,
motion, or conference report on that concurrent resolution)
that would exceed any of the discretionary spending limits set
forth in section 251(c) of the Balanced Budget and Emergency
Deficit Control Act of 1985.
``(3) Point of order against a specific provision.--If the
Presiding Officer sustains a point of order under paragraph (1)
with respect to any separate provision of a bill or resolution,
that provision shall be stricken from the measure and may not
be offered as an amendment from the floor.
``(4) Form of the point of order.--A point of order under
this section may be raised by a Senator as provided in section
313(e).
``(5) Conference reports.--If a point of order is sustained
under this section against a conference report the report shall
be disposed of as provided in section 313(d).
``(6) Exceptions.--This subsection shall not apply if a
declaration of war by the Congress is in effect or if a joint
resolution pursuant to section 258 of the Balanced Budget and
Emergency Deficit Control Act of 1985 has been enacted.''.
SEC. 5. ENFORCEMENT AGAINST BUDGET EVASION.
(a) In General.--Title III of the Congressional Budget Act of 1974
is amended by inserting at the end the following:
``budget evasion point of order
``Sec. 316. (a) Discretionary Spending Limits.--It shall not be in
order to consider any bill or resolution (or amendment, motion, or
conference report on that bill or resolution) that waives or suspends
the enforcement of section 251 of the Balanced Budget and Emergency
Deficit Control Act of 1985 or otherwise would alter the spending
limits set forth in that section.
``(b) Pay-As-You-Go.--It shall not be in order to consider any bill
or resolution (or amendment, motion, or conference report on that bill
or resolution) that waives or suspends the enforcement of section 252
of the Balanced Budget and Emergency Deficit Control Act of 1985 or
otherwise would alter the balances of the pay-as-you-go scorecard
pursuant to that section.
``(c) Directed Scoring.--It shall not be in order in the Senate to
consider any bill or resolution (or amendment, motion, or conference
report on that bill or resolution) that directs the scorekeeping of any
bill or resolution.
``(d) Waiver and Appeal.--This section may be waived or suspended
in the Senate only by an affirmative vote of three-fifths of the
Members, duly chosen and sworn. An affirmative vote of three-fifths of
the Members of the Senate, duly chosen and sworn, shall be required in
the Senate to sustain an appeal of the ruling of the Chair on a point
of order raised under this section.''.
(b) Table of Contents.--The table of contents for the Congressional
Budget Act of 1974 is amended by inserting after the item for section
315 the following:
``316. Budget evasion point of order.''. | Budget Enforcement Act of 2002 - Amends the Balanced Budget and Emergency Deficit Control Act of 1985 to extend through FY 2007 the discretionary spending limits (spending caps) for specified nondefense categories in new budget authority and outlays.Extends the provisions of such Act for an additional five years, including the pay-as-you-go requirement. Prohibits sequestration in any surplus year.Amends the Congressional Budget Act of 1974 concerning budget evasion points of order against legislation which evades specified budget enforcement mechanisms such as the discretionary spending limits, pay-as-you-go, and directed scoring. |
hemolytic uremic syndrome ( hus ) is the most frequent cause of acute renal failure in children .
the traditional diagnostic criteria for this syndrome include hemolytic anemia with fragmented erythrocytes , thrombocytopenia , and renal failure .
the epidemic form of hus occurs mostly as a result of hemorrhagic colitis . in 90% of hus cases ,
infection with shiga toxin- ( stx- ) producing escherichia coli ( stec ) is strongly implicated .
stx is divided into two main groups , referred to as stx1 and stx2 , which share approximately 56% amino acid sequence similarity .
stx2 is a more potent cause of severe hus and central nervous system ( cns ) impairment .
stx is a 71-kda protein composed of a 32-kda a subunit ( stxa ) and five 7.7-kda b subunits ( stxb ) .
stxa has n - glycosidase activity that removes the adenine of the 28s rna within the 60s ribosomal subunit , thereby rendering ribosomes inactive for protein synthesis .
stxb specifically binds to the cell membrane of the globotriaosylceramide ( gb3 ) receptor , which is present in specific mammalian host cells .
stx is thought to enter the bloodstream through inflamed intestinal mucosa , then bind with low affinity to blood cells , specifically polymorphonuclear leukocytes , thereby being transported to the target organs .
gb3 , the functional receptor for stx , is present on the surfaces of various cell types , including human glomerular endothelial cells , glomerular epithelial cells , and human brain endothelial cells ( hbecs ) .
stx binding to target cells expressing gb3 inhibits protein synthesis and induces apoptosis and necrosis .
approximately , 30% of patients with hus suffer from cns complications , and these patients have the poorest prognosis .
although thrombotic microangiopathic damage is characteristic of hus and is thought to result from the direct cytotoxic effects of circulating stx on the vascular endothelium , there is no consensus on the pathogenic mechanisms responsible for brain involvement in hus .
however , a possible role for the inflammatory response provoked by cytokines has been suggested .
clinical studies have demonstrated that patients with hus have elevated plasma levels of cytokines such as tumor necrosis factor ( tnf- ) , interleukin-1 ( il-1 ) , and interleukin-6 ( il-6 ) . in the presence of tnf- or il-1 ,
furthermore , tnf- and il-1 upregulate the expression of gb3 in endothelial cells . similarly , although it has been demonstrated that hbecs are very resistant to stx - induced cytotoxicity , inflammatory mediators , such as tnf- and/or il-1 , markedly increase the sensitivity of hbecs to stx cytotoxicity , which is due to modulation of expression of gb3 .
several components of the gb3 metabolic pathway may be involved in cytokine - stimulated gb3 expression .
gb3 is synthesized from lactosylceramide and udp - galactose by gb3 synthase ( galt6 ) .
the inflammation associated with hus is marked by the release of chemokines , and the levels of il-8 and mcp-1 are significantly increased in urine samples collected from hus patients .
purified stxs directly induce the expression of the neutrophil chemoattractant il-8 in human intestinal epithelial cells .
these stx - induced increases in il-8 synthesis by intestinal epithelial cells could be important in augmenting the host mucosal inflammatory responses to stec infection .
endothelial cells exposed to stx2 release inflammatory chemokines , such as il-8 and mcp-1 , which stimulate adhesion and transmigration of leukocytes .
however , in brain parenchymal cells and neuroglial cells , expression of chemokines in response to stx has not been studied .
intravenous inoculation of rabbits with stx2 caused severe cns injury associated with the invasion of stx2 through the bbb .
some authors have reported that intracerebroventricular administration of stx2 causes neuronal death and glial cell damage in the rat brain .
transmission electron microscopy studies have revealed apoptotic neurons , ultrastructural alterations of glia , and demyelinated fibers .
these findings support the contention that stx2 has a direct effect on brain neuroglial cells .
the brain contains neuronal , glial ( e.g. , astrocytes , microglia , and oligodendrocytes ) , and endothelial cells . human astrocytes ( hasts ) are the most abundant type of glial cell in the human brain .
they play key roles in development , homeostasis , inflammatory responses , and repair of the cns by producing a wide variety of cytokines , chemokines , and growth factors and by expressing receptors for these molecules .
these chemokines play important roles in development , growth , cell migration , production of free radicals , apoptosis , t - cell activation , neoplasia , inflammatory regulation in response to injury , wound healing , tissue repair , and macrophage recruitment , as well as in interactions with pathogens , including viruses [ 2629 ] .
chemokines and their receptors play important roles in several neurodegenerative and inflammatory diseases of the cns , including trauma , stroke , alzheimer 's disease , multiple sclerosis , cns tumors , and human immunodeficiency virus encephalitis [ 3032 ] . we speculated that stxs would act directly on astrocytes by inducing the production of chemokines and play a role in cns complications . in the present study , we investigated how gb3 expression , including galt6 , in hasts is controlled by inflammatory cytokines .
in addition , we sought to obtain further evidence that stx2 acts to produce chemokines in hasts and that these chemokines participate in the pathogenesis of cns complications associated with hus .
toxicity was determined to be greater than 10 units per milligram using a vero cell assay .
all reagents were purchased from sigma chemical co. ( st . louis , mo , usa ) .
hasts derived from human fetal brain tissue ( lonza , walkersville , md , usa ) were routinely subcultured every 6 days in clonetics astrocyte growth medium ( lonza ) .
cells were reseeded after reaching confluence at 3,500 cells per square centimeter and were incubated at 37c in a humidified atmosphere containing 5% co2 .
analysis of gb3 expression stimulated by il-1 was conducted by immunohistochemistry using the vectastain elite abc kit ( vector labs , burlingame , ca , usa ) .
the cells were stimulated for 48 h with il-1 and fixed in 4% paraformaldehyde for 10 min at room temperature .
slides were prepared and incubated in rat anti - human cd77 igm antibody ( 1 : 100 dilution ; beckman coulter , brea , ca , usa ) or pbs for 8 h at room temperature , then washed and incubated with a 1 : 100 dilution of secondary antibody ( supplied in the vectastain kit ) at room temperature for 1 h. the colorimetric reaction was obtained using 0.5 mg / ml diaminobenzidine ( dab ) substrate solution ( vector labs ) with 0.02% h2o2 .
hasts grown in six - well plates were incubated in il-1 ( 10 to 10 mol / l ) or tnf- ( 10 to 10
mol / l ) . at 0 , 8 , and 24 h postinoculation ,
total rna was isolated using the rneasy mini kit ( qiagen , valencia , ca , usa ) , with an rnase - free dnase ( qiagen ) treatment for 30 min in accordance with the manufacturer 's instructions .
rna was reverse transcribed to produce cdna using the prime script rt reagent kit ( takara bio , otsu , japan ) .
real - time quantitative polymerase chain reaction ( pcr ) was performed using sybr green pcr master mix and the thermal cycler dice real - time system ( takara bio ) .
the real - time pcr primers specific for galt-6 and the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase ( gapdh ) are listed in table 1 .
the pcr conditions were 95c for 10 s , followed by 40 cycles of 95c for 5 s and 60c for 30 s. the relative amounts of mrna were determined from the threshold cycle values of the reference gene , gapdh .
all further calculations and statistical analyses were carried out based on these values and are referred to as relative expression ratios .
hasts grown in six - well plates were incubated in 10 and 10 mol / l stx2 . at 0 , 24 , and 48 h postinoculation , cell supernatants from treated hasts
the elisas for il-8 and monocyte chemoattractant protein-1 ( mcp-1 ) were performed using the corresponding quantikine colorimetric sandwich elisa kits ( r&d systems , minneapolis , mn , usa ) in accordance with the manufacturer 's protocol .
chemokines were quantified by measurement of absorbance at 450 nm ( a450 ) with a 680 microtiter plate reader ( bio - rad laboratories , hercules , ca , usa ) .
the assay sensitivities were 4 pg / ml ( il-8 ) and 5 pg / ml ( mcp-1 ) .
hasts grown in six - well plates were incubated with either 10 or 10 mol / l stx2 , 10 mol / l stx2 with 10 mol / l il-1 , or 10 mol / l il-1 alone . at 0 , 8 , and 24 h postinoculation ,
total rna was extracted and real - time quantitative pcr performed using the methods described previously .
the real - time pcr primers specific for il-8 and mcp-1 ( takara bio ) are listed in table 1 .
the pcr conditions were one cycle at 95c for 10 s , followed by 40 cycles of 95c for 5 s and 60c for 30 s. the relative amounts of the mrna were determined as described previously .
the means sd were determined , and the mean values in the two separate groups were compared using a student 's t - test .
proinflammatory cytokines increase the expression of stx receptor gb3 on the surface of different stx target cells . to determine the levels of gb3 expression in hasts treated with il-1
treated for 48 h with 10 mol / l il-1 , a relatively high level of gb3 ( figure 1(a ) ) was detected in comparison to the untreated controls ( figure 1(b ) ) .
conversely , no change in gb3 level was detected in hasts treated with tnf- ( data were not shown ) .
it has been demonstrated using hbecs and intestinal epithelial cells that inflammatory cytokines increase gb3 expression levels by generating lactosylceramide through the activation of galt6 .
immunohistochemistry revealed that the expression of gb3 in hasts was increased by il-1. in addition , we investigated the expression of galt6 mrna relative to that of the untreated controls following treatment with il-1 ( 10 to 10 mol / l ) or tnf- ( 10 to 10 mol / l ) for 8 or 24 h. at 8 h , il-1 ( 10 to 10 mol / l ) treatment resulted in significant induction ( p < 0.05 ) of galt6 mrna relative to the untreated controls ( figure 2(a ) ) .
a 6.5-fold increase in the level of galt6 mrna was induced with 10 mol / l il-1. tnf- treatment showed a similar trend to il-1 treatment at 8 h , but it was not significant ( figure 2(b ) ) .
astrocytes are an important source of chemokines that play a role in brain inflammatory responses . to investigate whether expression of il-8 and mcp-1 mrna was increased in hasts treated with stx2 , we used real - time pcr . following treatment with 10 to 10 mol / l stx2 for 8 or 24 h ,
real - time quantitative pcr was performed to verify the expression of il-8 and mcp-1 transcripts . following treatment with stx2 ,
il-8 mrna induction was significantly elevated ( p < 0.05 ) relative to the untreated controls ( figure 3(a ) ) .
a 256-fold increase in the level of il-8 mrna was induced by 10 mol / l stx2 , and a 1,155-fold increase was induced with 10 mol / l stx2 at 8 h. a 5.7-fold increase of mcp-1 mrna was induced by 10 mol / l stx2 , and an 11.6-fold increase was induced with 10 mol / l stx2 at 8 h , in comparison with the untreated controls ( figure 3(b ) ) . to determine whether the upregulation of chemokine mrna was accompanied by release of these chemokines into the medium , hasts were exposed to 10
mol / l and 10 mol / l stx2 for 24 and 48 h , and the concentrations of chemokines in the medium were measured by elisa .
treatment of hasts with 10 mol / l and 10 mol / l stx2 increased secretion of il-8 into the medium relative to the control cultures at 24 and 48 h ( figure 4(a ) ) .
the concentrations of il-8 in the medium were significantly higher in the stx2-treated cultures , especially for 10 mol / l stx2 , than those in the control cultures at 24 and 48 h. similarly , treatment of hasts with 10 mol / l and 10 mol / l stx2 increased the secretion of mcp-1 into the medium relative to the control cultures at 24 and 48 h ( figure 4(b ) ) . unlike il-8 , mcp-1 was released in the absence of stx2 stimulation ( figure 4(b ) ) . using real - time pcr
, we found that the expression of galt6 mrna was increased by stimulation with il-1 , and immunohistochemistry demonstrated that the level of gb3 expression in hasts was also increased by il-1 stimulation . to investigate whether the increase of gb3 expression induced by il-1 stimulation correlated with the expression of chemokine mrna , we treated hasts with stx2 and il-1. induction of il-8 mrna upon stimulation with 10 mol / l stx2 and 10 mol / l il-1 combined was significantly greater ( p < 0.05 ) at 24 h than that resulting from stimulation with either agent alone at the same concentration ( figure 5 ) .
a 3,700-fold increase was induced by this combination of stx2 and il-1 , in comparison with the control levels .
coincubation of stx2 with il-1 did not elicit a significant increase in the level of mcp-1 mrna ( data were not shown ) .
although the pathogenesis of cns involvement in hus is not fully understood , the disruption and increased permeability of the bbb and neuronal disturbance resulting from hbec injury are central events in cns complications observed during the acute phase of hus . in a previous histopathologic study , mizuguchi et al . showed that intravenous administration of stx2 to rabbits resulted in hemorrhage and necrosis of both neural and endothelial cells in the brain .
moreover , an in vivo study has shown that stx2 injected intravenously into rabbits was detected in the cerebrospinal fluid ( csf ) and that influx of stx2 into the csf caused injury to the tight junctions between ependymal cells , resulting in destruction of the bbb .
some authors have reported that intracerebroventricular administration of stx2 causes neuronal death and glial cell damage in the rat brain .
however , it is unclear how stx2 affects neuroglial cells during an inflammatory response .
hasts comprise 55%60% of the total number of human brain cells and are involved in virtually every type of brain pathology .
hasts play key roles in the development , inflammation , and repair of the cns by producing a wide variety of chemokines . under inflammatory or otherwise pathologic conditions ,
hasts become activated and display enhanced production of several cytokines , chemokines , and growth factors .
in addition , hasts generally start to proliferate under such conditions , a phenomenon known as astrogliosis
. therefore , knowledge of the cellular response of hasts to stx is essential to understand the neuropathology observed in the severe cases of hus . in this study ,
il-1 treatment of hasts increased both gb3 and galt6 mrna expression , as determined by immunohistochemistry and real - time pcr , respectively .
in addition , treatment of hasts with stx2 induced production of the chemokines il-8 and mcp-1 .
these findings suggest that stx2 triggers an immune response through the expression of chemokines in hasts .
toxin binding to gb3 is the primary determinant of the cytotoxic and pathologic effects of stx protein .
previous studies have highlighted the role of proinflammatory agents in enhancing the sensitivity of different target cells , including hbecs , to the effects of stx through upregulation of gb3 expression [ 9 , 35 ] .
primary hbecs become susceptible to stx when they express gb3 in response to tnf- , further exacerbating the disease process .
therefore , we investigated whether gb3 expression in hasts is increased by inflammatory cytokines . using real - time pcr
, we determined that the expression of galt6 mrna was increased by il-1 stimulation , and immunohistochemistry showed that the level of gb3 expression in hasts was increased by il-1 stimulation .
these results demonstrated that hasts , which are cns parenchymal cells , express gb3 , and that this expression is increased by inflammatory cytokines . in hbecs , il-1 and tnf- increased the expression of gb3 and enhanced the toxicity of stx .
only il-1 increased the expression of galt6 mrna and increased the level of gb3 expression in hasts .
treatment with tnf- elicited a response similar to that for il-1 in terms of the expression of galt6 mrna at 8 h , although the degree of similarity was not significant . in this study , the mechanism by which il-1 increased the level of gb3 expression in hasts more than tnf- is not understood , although it may be a result of differences in cell types , and further investigations of this are required .
chemokines , a family of proinflammatory cytokines , are divided into two subfamilies : the cxc family , represented in this study by il-8 , and the cc family , represented here by mcp-1 .
chemokines stimulate target cell - specific directional migration of leukocytes and may be potent mediators of inflammatory processes .
human il-8 is a proinflammatory chemokine secreted predominantly by monocytes , endothelial cells , and glial cells and acts as a chemoattractant and activator of neutrophils via cxcr1 and cxcr2 receptor signaling .
mcp-1 is a potent chemotactic factor for monocytes and plays an important role in the regulation of repair processes and cellular interactions in the cns [ 25 , 26 ] .
it can be expressed by many cell types including microglia , astrocytes , and neurons [ 20 , 21 ] . in recent years
, it has been shown that chemokines play many roles in inflammation in the cns and are responsible for the development of various neurodegenerative diseases and ischemic damage to brain cells [ 17 , 18 ] .
in addition , the levels of mcp-1 and il-8 are significantly elevated in the csf of infants with amyotrophic lateral sclerosis , japanese encephalitis , or hypoxia - ischemia .
we found that by stimulating hasts with stx2 chemokines such as il-8 and mcp-1 were produced , the production of il-8 being particularly marked .
elevated levels of il-8 and mcp-1 mrna were found in toxin - treated cells in comparison to the untreated controls . il-8 and
mcp-1 proteins were found at higher levels in the conditioned media of stx2-treated cells than in those of untreated cells , and the chemokines il-8 and mcp-1 were produced by hasts upon stimulation with stx .
several studies have demonstrated that stx induces the expression of il-8 and mcp-1 in intestinal epithelial cells , endothelial cells , and monocytes and that the levels of il-8 and mcp-1 are significantly increased in urine samples collected from patients with hus .
it has , therefore , been suggested that chemokines such as il-8 and mcp-1 play a specific role in the pathogenesis of hus . for hus patients , a high peripheral polymorphonuclear neutrophil count at presentation
activated polymorphonuclear neutrophils could contribute to the brain inflammatory response and participate in the secondary damage following bbb disruption in hus .
stx2 induces expression of several chemokines , such as il-8 and mcp-1 , in astrocytes , and might constitutively induce the inflammatory response . in a mouse model of hus ,
neutralization of chemokines resulted in decreased renal fibrin deposition , suggesting that disrupting or eliminating these macrophage chemokines may be a useful treatment for the kidney damage associated with hus .
currently , it is unclear whether il-8 and mcp-1 are induced in the cns . in the present study , we found that astrocytes were responsive to stx2 and produced il-8 and mcp-1 . in biological systems ,
further studies will need to address whether il-8 and mcp-1 are induced by stx2 in the cns , and what effects they exert . no therapy for hus encephalopathy has yet been established .
however , fujii et al . showed that betamethasone sodium phosphate pulse therapy reduced the mortality rate and prolonged the survival period of rabbits with stx2-toxemia .
betamethasone sodium phosphate is routinely used as a steroid therapy for patients with brain edema .
dexamethasone reduces the permeability of the normal bbb in mice . in brain astrocytes , kim et al .
showed the coordinated regulation of angiotensin-1 and vascular endothelial growth factor ( vegf ) by dexamethasone , suggesting a novel mechanism underlying glucocorticoid - induced stabilization of the bbb .
in addition , rock et al . examined cytokine and chemokine expression with and without dexamethasone in human microglia and astrocytes infected with mycobacterium tuberculosis .
steroid protective effects are thought to be mediated by immunomodulatory activities , such as a decrease in the production of proinflammatory cytokines .
therefore , anti - inflammatory compounds may have therapeutic potential for stx - induced neurological manifestation .
investigations into the glucocorticoid regulation of chemokine expression by stx2 in hasts are currently underway . in summary ,
our results suggest a possible relationship between excessive chemokine production in the cns and brain damage once stx2 reaches the brain parenchyma .
we propose that suppression of chemokine production could be a new strategy for treatment of cns damage in hus encephalopathy .
in this study , we investigated the inflammatory responses in human astrocytes treated with stx2 .
immunohistochemistry and real - time pcr revealed that the expression of globotriaosylceramide ( gb3 ) , the receptor for stx2 , and gb3 synthase ( galt6 ) in hasts was increased by interleukin-1 ( il-1 ) .
chemokines in the cns may be associated with the pathogenesis of cns manifestations with hus . | infection with shiga toxin- ( stx- ) producing escherichia coli can lead to hemolytic uremic syndrome ( hus ) .
approximately , 30% of patients with hus suffer from complications in the central nervous system ( cns ) , which is an important determinant of mortality in such patients .
autopsy shows mostly edema and hypoxic - ischemic changes in the cns , often with microhemorrhages .
it has been suggested that stx - induced damage to human brain endothelial cells , which are essential constituents of the blood - brain barrier , plays a crucial role in the development of the cns complications .
however , it is unclear whether stx affects brain neuroglial cells . in the present study , we investigated the direct involvement of stx in the inflammatory responses of human astrocytes ( hasts ) treated with stx .
immunohistochemistry and real - time pcr revealed that the expression of globotriaosylceramide ( gb3 ) , the receptor for stx2 , and gb3 synthase ( galt6 ) in hasts was increased by interleukin-1 ( il-1 ) .
expression of both interleukin-8 ( il-8 ) and monocyte chemoattractant protein-1 ( mcp-1 ) mrna in hasts was significantly upregulated by stx2 .
these results suggest that stx2 induces inflammatory responses , particularly through expression of chemokines , in hasts expressing gb3 and may , thus , affect brain glial cells , playing a key role in the pathogenesis of cns manifestations associated with hus . |
Gardaí investigating the death of a 24-year-old man who collapsed on board an Aer Lingus flight are hoping a postmortem on Monday will establish how he died.
The Brazilian man was travelling on a flight EI 485 from Lisbon to Dublin yesterday afternoon when he became agitated and, in the course of being restrained, bit a passenger assisting the crew.
It is understood the man was subdued and handcuffed, but some time later he collapsed and was attended to by a doctor who advised the captain he was in a critical condition.
A passenger on the flight told Cork’s 96FM how he saw the Brazilian man “shaking violently” as he suffered what appeared to be a number of seizures.
“The noise he was making was like something that I’d never heard before and wouldn’t like to hear again,” said the male passenger, describing the sounds as “guttural”. “It was like a deep anguish, that is the best way I can describe it. It was very, very troubled.”
The plane’s captain contacted the Irish Aviation Authority’s North Atlantic Communications Centre at Ballygireen, Co Clare to say he had a medical emergency.
The flight diverted to Cork Airport and landed at about 5.40pm and the man was attended by paramedics but pronounced dead soon after.
His body was removed from the airport to Cork University Hospital (CUH) where assistant state pathologist, Dr Margot Bolster is due to carry out the postmortem.
Gardaí arrested a woman they believe was travelling with the man on suspicion of drug trafficking.
The 44-year-old Portuguese woman was arrested after gardaí searched her luggage at Cork Airport and found two kilos of a powdered substance which they believe are illegal drugs.
The woman was detained under drug trafficking legislation and taken to Togher Garda station for questioning while the powder substance found in her luggage has been sent to the Forensic Science Ireland laboratory at Garda headquarters for analysis.
It is understood the woman, believed to have been sitting beside a 24-year-old Brazilian man who died on the flight, came forward after the man was pronounced dead to say that she knew him.
Violent
Gardaí are hoping the postmortem will establish whether or not the man may have ingested a substance which led to him becoming agitated, violent and then unwell on the flight.
The male passenger who was attacked and bitten in the incident was taken to CUH and treated for his injuries.
Gardaí took witness statements from the six crew members and 168 passengers who were on the flight, which left Lisbon at 3.30pm.
It is understood passengers were later bussed to Dublin but the plane was detained by gardaí at Cork Airport and is being treated as a crime scene by investigating officers.
Garda technical experts will carry out a full forensic examination of the plane on Monday.
It is understood the man, who was sitting at the rear of the plane, became agitated midway into the two and a half hour flight before attacking a passenger seated near him.
The airline issued a statement on Sunday night which confirmed “Aer Lingus flight EI 485 Lisbon to Dublin, diverted into Cork due to a medical emergency on board.
“There were 168 guests and six crew members on board. The flight landed safely at 17.40, local time.”
The company said it was assisting gardaí with their inquiries.
Under the Air Navigation andTransport Act 1998, the man’s death becomes a Garda matter once the plane has taken off from Lisbon Airport as the plane is registered as an Irish aircraft.
Gardaí were last night trying to contact the dead man’s family through the Brazilian Embassy in Dublin.
Were you on flight EI 485? Send any information or updates to newsdesk@irishtimes.com ||||| Get daily updates directly to your inbox + Subscribe Thank you for subscribing! Could not subscribe, try again later Invalid Email
A man died onboard an Aer Lingus flight this evening, forcing the plane to make an emergency landing.
Flight EI 485 was travelling from Lisbon, Portugal, to Dublin, when it is understood a passenger onboard “ran amok”, apparently “biting” one of his fellow passengers.
Reports claim the man began “biting another passenger” and was later restrained by crew after becoming “extremely violent”.
It is understood the man later became unwell after being restrained and fell into a state of unconsciousness, before being pronounced dead on the Dublin-bound flight.
Crew broadcast an emergency ‘Pan Pan’ message three times in quick succession and advised air traffic controllers of an incident on board the Airbus A320-200.
The crew had been in contact with controllers at the Irish Aviation Authority’s North Atlantic Communications Service centre at Ballygirreen before landing at Cork airport at around 5.40pm.
The pilot informed controllers of the situation on board and requested clearance to divert and land at the airport after the man started to become “extremely violent”.
He told controllers that there was a passenger “running amok” and that he had “injured one or two passengers”.
It is also understood there was a doctor on board who tried to assist the restrained passenger.
While nearing Cork airport, the crew informed controllers there was a doctor on board treating “a gentleman”, but said the man in question no longer had a pulse.
(Image: RTE)
All 168 passengers and six crew members were moved off the plane and into the airport.
Airport paramedics and a HSE ambulance responded to the scene after the captain declared the incident a medical emergency mid-flight.
It is also understood a second man was injured during a biting incident, as he tried to help the deceased.
The injured man was taken to hospital following the emergency landing.
Reports tonight said Gardai were at the airport investigating the incident and speaking to some of the passengers about what happened in the cabin.
The deceased was travelling alone and it is not believed he was Irish, but may have been studying in the country.
Aer Lingus last night issued a statement about the incident saying the plane was forced to land due to a “medical emergency on board”.
They said: “Aer Lingus flight EI 485 Lisbon to Dublin, diverted into Cork due to a medical emergency on board.
“There were 168 guests and six crew members on board. The flight landed safely at 17.40 local time.”
All other flights to and from Aer Lingus were believed to be running on time this evening. | – Authorities are hoping a postmortem on a dead passenger will explain the madness that unfolded on a flight from Lisbon to Dublin on Sunday night. According to the Irish Mirror, the man went berserk on Aer Lingus Flight 485 and bit another passenger before crew members were able to restrain him. The man became unconscious after he was restrained and was pronounced dead by a doctor on board before the flight made an emergency landing in Cork, RTE reports. The pilot told air traffic controllers that he was landing because the man had "run amok" on the plane and become "extremely violent," reports the Mirror. A postmortem will be carried out Monday on the passenger, a 24-year-old Brazilian man who became agitated around halfway through the 2.5-hour flight, reports the Irish Times. The Times reports that the bitten man was taken to a hospital in Cork, while the other 166 passengers and crew members were taken to Dublin by bus because the aircraft is now a crime scene that will be examined by a forensics team. (A doctor returning from her honeymoon ended up delivering a baby on a flight to LA when a passenger went into labor early.) |
DENVER – A missing elderly man who authorities discovered dead in an elevator at a Denver apartment complex last month may have reached out for help by pressing the elevator’s emergency button.
Isaak Komisarchik, 82, had early-onset dementia and was last seen July 5. He was reported missing, and Denver Police made a concerted effort with Komisarchik’s family to locate him. Despite their efforts, Komisarchik’s body was located in an elevator car at the Woodstream Village apartments, 10050 East Harvard Avenue, on July 31.
Tenants at the apartment complex complained of an awful smell coming from the parking garage elevator, leading to the discovery of the body.
Denver Police continue an active investigation into the man’s death, and Denver Fire officials are now revealing new details about the events leading up to Komisarchik’s death.
First reported by the Denver Post, Denver Fire officials say they’ve learned Komisarchik pressed an emergency button in the elevator twice on July 6 before he died.
“Something is not right, and police are going to make a determination on what that is,” Capt. Greg Pixley, of Denver Fire, said.
Pixley said the activation of the elevator’s emergency button was recorded electronically twice, although officials never received the call.
Pixley said Denver Fire was never notified that the elevator was taken out of service and it met the appropriate fire code standards for 2016 and had the appropriate permits for operation in 2017.
Tenants say the elevator wasn't working and that few people parked in the garage during summer months. If that's the case, it raises questions about why an elevator company wasn't called.
Pixley said MEI Total Elevator Solutions monitors the elevator for Woodstream Village. The company issued the following response.
"We are saddened by the tragic loss of life and extend our deepest condolences to Mr. Komisarchik's family and friends. The elevator cab where he was found is located in a parking garage that is under renovation construction and not currently in active use. We are continuing to investigate the circumstances surrounding the incident with the local authorities," a Greystar Management Services representative said Thursday.
Denver Police said MEI Total Elevator Solutions received the distress call from the elevator and notified Woodstream's management. However, police say apartment workers failed to check the parking garage elevator after checking two other elevators in the building.
Police in Denver are now working to learn why Komisarchik wasn’t able to escape the elevator and why authorities weren't notified of the emergency call.
Read past reporting here.
||||| An elderly man who died in a parking garage elevator pushed the emergency button twice during an 8-minute span on July 6, but got no response despite Denver code requiring elevator operators to monitor emergency notifications around the clock.
Unable to escape the elevator car — possibly because of dementia — 82-year-old Isaak Komisarchik died some time between the morning of July 6 and Aug. 2, when elevator repair workers finally discovered the body after multiple residents of the apartment complex reported a terrible stench.
When a Denver firefighter responded she watched an elevator maintenance worker push the button. The elevator doors opened. Elevator maintenance workers had just found Komisarchik’s body inside the car, Denver Fire Department spokesman Capt. Greg Pixley said.
A criminal investigation confirmed the number of times the emergency button was pushed, Pixley said. Now detectives are trying to determine why no one responded.
“Something is not right,” Pixley said.
Komisarchik died in an elevator that served a parking garage at the Woodstream Village apartments, 10050 E. Harvard Ave., that had been closed for renovation.
On Aug. 8, Pixley said MEI Total Elevator Solutions monitors the elevator for Woodstream. He later said that he may have misspoken. MEI is not Woodstream’s elevator’s monitor, he said on Aug. 16.
On Aug. 15, Mike Klehr, MEI Vice President of Field Operations, sent an email to the newspaper saying that although the company provides maintenance for the elevators for Woodstream, the company does not provide the elevator emergency monitoring service.
“On behalf of MEI – Total Elevator Solutions, we offer our deepest condolences to Mr. Komisarchik’s family. MEI has fully cooperated with local authorities in their investigation of this matter,” Klehr wrote in the message.
“We are saddened by the tragic loss of life and extend our deepest condolences to Mr. Komisarchik’s family and friends,” Greystar Management Services, which manages Woodstream, said in a statement released by spokeswoman Lindsay Andrews.
She wrote that the elevator was not in use due to the renovation and said Greystar is “continuing to investigate the circumstances surrounding the incident with the local authorities.”
She declined to comment about why no one responded to the emergency calls.
Denver Medical Examiner’s spokesman Steven Castro said the cause of Komisarchik’s death has not yet been determined. Pixley said it can be difficult to determine a cause of death when a body is badly decomposed.
Numerous Woodstream residents complained to managers of a strong odor emanating from the garage area but nothing had been done. Andrews declined to comment about the complaints.
The fact that Komisarchik pushed the emergency button twice adds a new perplexing dimension to the incident. It appears Komisarchik did what he needed to do to get help and yet the closely regulated system for rescuing people trapped in elevators failed.
“The elevator wasn’t inoperable,” said John White, spokesman for Denver police, contradicting numerous reports that elevator was not working. “How he got in there and when he got in there is obviously what we’re trying to figure out.”
Misconceptions about the discovery of Komisarchik’s body make it impossible to fully grasp just how bizarre the incident was, according to officials and residents of the apartment complex. Some officials initially reported that Komisarchik’s body was found in the elevator shaft, Pixley said.
Komisarchik was last seen wearing pajamas at 2:30 p.m. on July 5 at a nearby nursing facility on the 9900 block of East Yale Avenue. His disappearance sparked a large dragnet in which missing persons posters were distributed and Denver firefighters searched five ponds near Woodstream in an attempt to find him.
According to city codes adopted in 1981, the interior of all elevator cars must have signaling devices including an emergency switch labeled “alarm” adjacent to the car’s operating panel and a phone or intercom labeled “help” allowing two-way communication with security.
In some cases the alarms are connected to the Denver Fire Department or an elevator monitoring company, which is responsible for investigating an emergency call. When the two-way communication phone or intercom is not connected to on-site security, a call must automatically be forwarded within 30 seconds to the elevator-monitoring company.
Elevators are regularly inspected by the fire department. The garage elevator at Woodstream Village was last inspected in December and found to be in good working order, Pixley said.
The fire department did not receive any emergency calls from that particular elevator car during the period of time Komisarchik was in it.
When police checked, two elevator calls from the same elevator car where Komisarchik was found were electronically logged at 9:09 a.m. and 9:17 a.m. on July 6, the morning after he disappeared.
Nearly a month later, a Denver fire lieutenant was inspecting an apartment complex adjacent to Woodstream that is also managed by Greystar when the maintenance manager received a call from elevator repair staff saying they thought there was a body in the elevator.
The fire lieutenant followed the manager to the nearby parking garage, Pixley said, but when she reached the garage, she smelled an odor so intense that she knew it was a body.
Updated Aug. 16, 2017 at 7:30 a.m. The following corrected information has been added to this article: Mike Klehr, MEI Vice President of Field Operations, said the company maintains the elevators at the apartment complex, but does not provide the emergency monitoring service. | – Investigators aren't sure exactly when 82-year-old Isaak Komisarchik died—but they know he died alone, trapped in an elevator, after calling for help and getting no response. The Denver man, who had dementia, was found dead in an elevator at an apartment complex on Aug. 2 after residents reported a terrible smell, the Denver Post reports. He had been reported missing almost a month earlier. Investigators found that Komisarchik pressed the emergency button in the elevator twice within 8 minutes on the morning of July 6 but received no response despite the city's requirement for emergency notifications to be closely monitored. The elevator led to a parking garage that was closed for renovations. "Something is not right, and police are going to make a determination on what that is," says Capt. Greg Pixley of Denver Fire, per the Denver Channel. Police say the elevator company notified the apartment complex's management after receiving the distress call, but workers failed to check the parking garage elevator after checking two other elevators in the complex. Komisarchik had last been seen wearing pajamas at a nearby nursing facility on the afternoon of July 5, and police searched a wide area, including several ponds, after his disappearance. "How he got in there and when he got in there is obviously what we're trying to figure out," police spokesman John White says. |
the cross section of the @xmath4 in terms of the center - of - mass ( c.m . )
energy is one of the most fundamental observables in quantum chromodynamics ( qcd ) .
the final hadrons are produced via a pair of quark - antiquark proceeded from a virtual photon by initial - state electron - positron annihilation . instead of the cross section for inclusive hadron production , the hadronic r - ratio @xmath6 is often used owning to its simplicity both on the experimental and the theoretical side , @xmath7 where @xmath8 is the photon - mediated lowest order muon pair production cross section with @xmath9 being the square of c.m .
energy and @xmath10 the electromagnetic coupling constant .
if no resonances are present , the @xmath6 values solely from the continuum hadrons are well known to be @xmath11 in the lowest order approximation , with @xmath12 being quark flavors and @xmath13 the corresponding quark charge .
the higher order corrections from the finite quark masses and the gluonic emission could be calculated by perturbative qcd ( pqcd ) @xcite .
so the measurement of @xmath6 is important for testing the validity of both pqcd calculation and hadronic vacuum polarization correction .
the @xmath6 for the continuum light hadron ( containing @xmath14 , @xmath15 and @xmath9 quarks ) production , denoted as @xmath2 in this letter , is usually used to test the validity of the pqcd calculation in relatively low energy region .
precise measurements of the @xmath2 near the @xmath16 threshold are reported by bes collaboration @xcite .
the @xmath2 value below the @xmath16 threshold is not affected by the first @xmath16 open charm resonance @xmath0 , therefore , determination of @xmath2 is very simple for the case .
the @xmath2 in the energy region from 3.650 to 3.732 gev is determined to be @xmath17 @xcite , which is in good agreement with @xmath18 predicted by pqcd @xcite .
however , the @xmath2 value in the open charm threshold region is overlapped with many resonances .
the obtained value varies widely among different fits , e.g. in or nearby the @xmath0 resonance .
it is extracted to be @xmath19 in the energy region from 3.660 to 3.872 gev @xcite and to be @xmath20 in the energy region from 3.650 to 3.872 gev @xcite .
there are obvious differences among the obtained @xmath2 values and also the pqcd calculation . as a matter of fact
, these extracted @xmath2 values depend on the treatment of resonances in the @xmath0 region .
therefore , a more reliable method is required to reasonably extract the @xmath2 value from the experimental data . in order to accurately extract the @xmath2 in the region of @xmath0 resonance ,
the anomalous line shape of the @xmath0 state should be treated carefully .
it has been found at the very beginning that the total cross sections of @xmath4 in the energy range between 3.700 and 3.872 gev could not be described well with only one breit - wigner ( bw ) resonance even using the energy - dependent width of the @xmath0 @xcite .
this is confirmed by the inclusive measurements of the @xmath5 , @xmath21 , @xmath22 reactions in the similar c.m .
energy region @xcite . in the analysis of the bes collaboration , a modified form of the energy - dependent width
is usually used in their fits to data , @xmath23 with @xmath24 being the final @xmath25meson momentum in the c.m .
system and @xmath26 fm the interaction radius of the @xmath27 .
the bw resonance with the width in eq . ( [ eq : beswidth ] ) could give an asymmetric line shape of the @xmath0 state , but does not describe well the dip around 3.82 gev . the deviation from the bw resonance of the @xmath0 state
has inspired a lot of interesting theoretical efforts @xcite .
experimental measurements from both bes and cleo collaborations show that the @xmath0 resonance mainly decays to @xmath16 channel though the specific decay ratio is still under discussion @xcite .
however , the rescattering of final @xmath16 is found to be not enough to account for its line shape deviation @xcite .
now it is explained to be the consequence of the interference between the @xmath0 resonance and the continuum background from the @xmath28 contribution @xcite .
its implication to the nature of @xmath0 state is also investigated in the fano mechanism @xcite . in the fano theory ,
the asymmetric line shape of states is produced by the interference of continuum and resonance , which is giving rise to a general physical phenomenon in many quantum system , e.g. the nuclear , atomic , condensed matter physics and molecular spectroscopy .
though the underlying physics of the @xmath0 state is still waiting for further exploration @xcite , the fano - type formula provides an appropriate and simple parameterized expression for describing the anomalous line shape of the total cross sections of the @xmath4 and @xmath16 . in this letter , we will use this formula to extract the @xmath2 value from experimental data reported by bes collaboration in the energy region between 3.650 and 3.872 gev@xcite .
at different c.m . energies .
the curves are the fits to the data with ( solid line ) and without ( dashed line ) @xmath29 fixed to the average value in pdg .
the data are measured by besiii collaboration @xcite .
, scaledwidth=50.0% ] the theoretical @xmath30 contains the contributions from continuum light hadron production @xmath31 , the continuum @xmath27 production @xmath32 , and the bare @xmath33 resonance production ( here and below , the @xmath0 is denoted as @xmath33 for short ) , which is written as @xmath34 with @xmath35 in besiii s fit @xcite .
the @xmath36 are the hadrons production cross section through the bare @xmath33 resonance in @xmath37 annihilation , and it could be written in terms of the form factor @xmath38 in the following way : @xmath39|f_{\psi^{'}}(s)|^2 \label{eq : cshadrons1 } \quad,\ ] ] where besides the factor from phase space , the bare @xmath33 form factor @xmath38 would be taken as the bw form : @xmath40 where @xmath41 and @xmath42 are the coupling constants of the @xmath33 to the @xmath16 and photon , respectively .
experiments indicate that the dominated decay channel of @xmath33 resonance is the @xmath16 .
hence , we may use the energy dependent width @xmath43 or an improved parameterization of @xmath44 in eq .
( [ eq : beswidth ] ) .
however , as we addressed in sec .
[ sec : intro ] , eq .
( [ eq : bareff ] ) is enough to describe the asymmetric line shape of the @xmath0 state , but does not describe well the dip around 3.82 gev .
the main weakness of above treatment is the totally separation of the continuum and resonant @xmath16 production in eq .
( [ eq : rseperate1 ] ) , but in fact , they are convoluted to each other .
this is justified by the besiii s fit results with the lower limit of @xmath45 within the uncertainties . keeping this in mind , we correct the eq .
( [ eq : rseperate1 ] ) as , @xmath46 the @xmath47 are the hadrons production cross section through the continuum @xmath27 and the @xmath33 resonance in @xmath37 annihilation , which should be alike to eq .
( [ eq : cshadrons1 ] ) : @xmath48 |f_{(c)+\psi^{'}}(s)|^2 \label{eq : cshadrons2 } \quad,\ ] ] instead of eq .
( [ eq : bareff ] ) , the fano - type form factor including the interference between resonance and continuum background could be written as @xcite @xmath49 with @xmath50 . in the present context
, the fano line shape parameter @xmath51 characterizes the relative transition strength into the @xmath33 state versus the @xmath16 continuum and can be related to the electromagnetic transition probability of the @xmath33 state .
it is an energy dependent variable in the original formula but regraded as a constant in the limited energy range of present interest .
the factor @xmath52 comes from the non - resonant background possibly associating with either the direct @xmath53 transition or the nearby @xmath28 or other charmonium states . because the background contribution would be different in various channels , the line shapes of the @xmath33
would not be the same in other channels , e.g. @xmath54 @xcite and @xmath55 @xcite .
this is obviously true for other hadron states . however , here we do not dig into this issue and parameterize @xmath52 as @xmath56 for simplicity .
it should be pointed out that the @xmath57 could be parameterized in other format , e.g. the coupled - channel models @xcite , however at the price of more complex
. the measured @xmath58 values versus c.m .
energies are taken from besiii s report @xcite , as shown in fig .
[ fig1 ] with statistical error bars .
we fit these @xmath59 values at each energy point to the theoretical formula described above using the least squares fitting method .
the objective function of the least squares to be minimized in the fit is defined as @xmath60 where @xmath61 is the measured value with the statistical error @xmath62 at the c.m .
energy @xmath63 , and @xmath64 is the corresponding theoretical value calculated by eq .
( [ eq : rseperate2 ] ) . in the considered narrow energy range ,
the @xmath2 could be viewed as a constant , independent of the energy .
the @xmath65 in eq .
( [ eq : edwidth ] ) tends to be in the range of 0 @xmath66 5 mev with large uncertainty in various fitting strategies and we do not include it into the following fits .
so we have seven free parameters ( @xmath2 , @xmath51 , @xmath67 , @xmath41 , @xmath42 , @xmath68 and @xmath69 ) in total .
because @xmath42 could be determined by the leptonic width @xmath70 , we perform two separate fits to the data . one of them ( fit i ) is to fix @xmath71 by the @xmath72 kev in particle data group @xcite , and the other is to let it being a free parameter ( fit ii ) . the curves in fig .
[ fig1 ] show these fits , where the solid line is fit i and the dashed line is fit ii .
the corresponding fitted parameters are shown in table [ table1 ] , in which the errors are only statistical ones .
the achieving @xmath73 1.38 and 1.23 respectively for fit i and ii are obviously smaller than besiii result @xmath74 @xcite .
particularly , fit ii gives a dip around 3.82 gev , which describes the data perfectly well .
it gives @xmath75 , whose central value is in excellent agreement with the prediction of pqcd @xcite and can directly be used to evaluate the strong coupling constant @xmath76 at the energy scale of around 3 gev .
however , the errors of the @xmath2 are on the same level of besiii result , and it still has some room for the improvement of the fit quality . these are probably due to the big uncertainties of the data , whose systematic errors are around the same scale of the statistical errors and not included here yet @xcite . as a reference , the @xmath77 could be close to 1.0 within above formula in a similar fit to the data of @xmath5 reactions @xcite . .
fitted parameters and achieving @xmath78 in fit i and fit ii , see text for details .
[ cols="<,<,<,<",options="header " , ] the parameter @xmath51 has big error in fit ii . as can be seen in eq .
( [ eq : fanoff ] ) , its value largely rests on the position of dip in the line shape , which is however has large uncertainty .
so it could deduce that the uncertainty of @xmath51 in fit ii comes from the coincidence of the fitted @xmath67 and the dip position .
in addition , the sign of @xmath51 varies in fit i and ii , and this is caused by the fitted @xmath67 in these two fits are lying on the opposite sides of the dip position .
it is found that the fitted @xmath67 both in fit i and ii are larger than the bw values in pdg @xcite , even considering their big uncertainties .
our obtained values should be treated as bare mass of the @xmath33 as argued in ref .
@xcite and depend on the way of dealing with the background term @xmath79 .
however , the corresponding dressed mass would be close to the pdg values and more sophisticated models are involved to extract its value @xcite .
the width @xmath80 mev at the nominal mass @xmath81 gev calculated with the obtained @xmath41 is consistent with the bw values in pdg .
the obtained @xmath42 in fit ii is bigger than that of the pdg value and the corresponding leptonic width @xmath29 is around 2.7 times bigger than that of the pdg .
this is possibly due to the rough treatment of the parameterization of the @xmath79 . in eq .
( [ eq : fanoff ] ) , the value of @xmath42 is directly relevant to the form of @xmath79 .
the physical interpretation of @xmath68 and @xmath69 would be difficult in present framework , though they are expected to be associated to the parameters of @xmath82 state @xcite .
however , it is impossible to accurately determine the mass and width of the @xmath82 by the present data .
it should be stressed that the extracted @xmath2 is stable and reliable regardless of the uncertainties of these parameters , as long as the line shape of @xmath33 state is correctly reproduced .
reaction extracted from measured r ratios at different c.m .
energies compared to that of the @xmath5 @xcite .
, scaledwidth=50.0% ] using the @xmath2 value extracted in fit ii , we can obtain the cross sections of @xmath83 by eq .
( [ eq : rseperate2 ] ) , as shown in fig .
the data of the @xmath5 cross section from besiii collaboration @xcite are plotted in the same figure for comparison .
the peak of @xmath16 production cross section is obviously smaller and narrower than that of @xmath84 , which hints a non - zero @xmath65 .
we calculate the cross section of @xmath84 production to be @xmath85 ( stat . )
nb at @xmath86 3774.2 mev , which is bigger than the recent cleo results @xmath87 at @xmath88 mev .
however , they are still consistent with each other when both the statistical and systematic uncertainties are taken into account .
thus , the non-@xmath16 decay ratio of the @xmath33 is waiting for more precise measurements .
in short summary , we have performed a renewed analysis of the measured @xmath2 value from besiii collaboration by treating the anomalous line shape of the @xmath0 resonance with a fano - type formula .
our fitting results are better than those in a simple breit - wigner resonance with energy dependent width , mainly because of the improvement on the description of the dip structure at about 3.82 gev .
the @xmath2 value is determined to be @xmath3 in the energy region between 3.650 and 3.872 gev from the data of besiii collaboration .
the central value is consistent with the pqcd calculation .
we also reliably extract the cross sections of the @xmath4 without the continuum light hadron production , which would be beneficial to our understanding of the properties of the @xmath0 state .
our prescription of fitting the asymmetry line shape of states is not only useful for pinning down the controversial decay ratios of @xmath0 state , but also meaningful for determining the @xmath1 value in higher energy region where is often overlapped with other resonances .
the proposed framework is easily extended to study other asymmetric line shapes of states and could be served as a simple fitting strategy to the experimental data .
one of the authors ( x. cao ) would like to thank prof .
h. lenske for useful discussion .
this work was supported by the national basic research program ( 973 program grant no .
2014cb845406 ) , the national natural science foundation of china ( grant nos . 11347146 , 11405222
, 11275235 and 11175220 ) and century program of chinese academy of sciences y101020br0 . | the anomalous line shape of the @xmath0 state has resulted in some difficulty in the determination of the @xmath1 value for the continuum light hadron production in the resonance energy range .
we parameterize the asymmetric line shape using a fano - type formula and extract the @xmath2 value to be @xmath3 from the data of besiii collaboration in the energy region between 3.650 and 3.872 gev . the small discrepancy between experiment and theory
is removed .
the cross sections of the @xmath4 are given by subtracting the part of continuum light hadron production and are compared to the data of the @xmath5 reaction .
r value , fano resonance , @xmath0 13.66.jn , 13.25.gv |
kepler s supernova remnant ( snr ; sn 1604 ) is one of the historical snrs .
the x - ray structure of the remnant shows a clear circular shape with a radius of about 100@xmath0 .
the distance estimations to the remnant have been scattered in a range of 35kpc ( e.g. , green 1984 ; schaefer 1994 ) .
although the far side of 5kpc supported by h i observations ( reynoso & goss 1999 ) has been adopted in recent literature , optical studies combining proper - motions with shock velocities of balmer - dominated filaments have preferred a near side of 2.9@xmath10.4kpc ( blair et al .
1991 ) or 3.9@xmath7kpc ( sankrit et al . 2005 ) .
the sn type of kepler s snr is very interesting .
based on the light curve of the kepler s sn , baade ( 1943 ) classified this remnant as a result of type - ia sn .
_ ginga _ spectrum from this remnant showed a strong fe k line , supporting that the kepler s sn was a type - ia sn ( hatsukade et al .
_ asca _ spectrum of this remnant showed strong k - shell lines from si , s , and fe , and the measured relative abundances supported type - ia origin ( kinugasa & tsunemi 1999 ) .
recent deep _ chandra _ observations detected strong emission lines from heavy elements almost everywhere in the remnant , again supporting type - ia origin ( reynolds et al .
2007 ) . on the other hand ,
the density of the ambient medium around the remnant was estimated to be so high ( at least 1@xmath8 ; e.g. , hughes & helfand 1985 ) at a large height of @xmath6470pc ( assuming the distance of 4kpc to the remnant ) from the galactic plane .
the high density of the ambient medium was considered to be a signature of circumstellar material ( csm ) which was blown off from a progenitor star as a stellar wind .
in addition to the existence of the dense surroundings , nitrogen - rich materials as a result of cno - processing in a massive progenitor star were detected in some optical knots ( van den bergh & kamper 1977 ; dennefeld 1982 ) .
these facts suggested that the kepler s remnant was core - collapse in origin .
also , bandiera ( 1987 ) suggested a massive runaway star as a possible progenitor of kepler s snr , since it was able to naturally account for the presence of the csm and the asymmetric structure of the remnant in optical wavelength .
recently , blair et al .
( 2007 ) proposed that the kepler s sn was categorized as a type - ia explosion in a region with significant csm , which was a small but growing class of type - ia sne named as type - ia / iin by kotak et al .
( 2004 ) . due to the large expansion of kepler s snr , it is the best target from which we can investigate the detailed preexisting structures of the csm for this rare kind of sne . here , we report proper - motions of the forward shocks on the overall rims of kepler s snr , by using archival _
chandra _ data .
we derive the distance to the remnant , combining the proper - motions we measure with the optically determined forward shock velocity ( sankrit et al .
2005 ) . also
, we present evolutional states in various portions of the remnant , which gives us critical information on structures of the surrounding csm .
kepler s snr was observed on three epochs in 2000 ( pi : holt , s. ) , 2004 ( pi : rudnick , l. ) , and 2006 ( pi : reynolds , s. ) .
we use the first ( obsid .
116 ) and the last ( obsid .
6715 ) observation to measure proper - motions of the forward shocks of this remnant .
these observations were , respectively , done in june 30th 2000 and august 46th 2006 , resulting in the time difference of 6.09 yr .
the entire remnant was covered on the acis - s3 back - illuminated chip in both observations .
we start our analysis from level 2 event files processed with calibration data files in caldb ver .
3.4.0 for obsid.116 , ver .
3.2.2 for obsid .
we exclude the high - background periods for data from obsid .
116 , whereas there seems no significant background flares for the data from obsid .
6715 so that we reject no data from the level 2 event file for this data set .
the resulting net exposure times for obsid . 116 and 6715 are 37.8ks and 159.1ks , respectively . to measure proper - motions of the forward shocks ,
we use an energy range of 1.08.0kev , i.e. , we do not use an energy range below 1.0kev where building up contaminants on the detector significantly reduce count rates for the second - epoch observation .
figure [ fig : image ] _ left _ shows the second - epoch image of the entire kepler s snr in the energy range of 1.08.0kev .
we register the two images by aligning them on four point sources that are obviously seen in the vicinity of the remnant . we determine the positions of the four sources in both observations , employing wavdetect software included in ciao ver
we find a systematic offset between the two images ; the sense of the difference is that the first - epoch image is south and west of the second .
we calculate the error - weighted mean offset of the four point sources to be 0@xmath0.14 in right ascension and 0@xmath0.19 in declination .
then , the first - epoch image is shifted in right ascension by 0@xmath0.14 and in declination by 0@xmath0.19 with respect to the second - epoch image . once the two images are registered
, we do not need to consider the absolute astrometric uncertainty of 0@xmath0.6 reported by the _ chandra _ calibration team as systematic errors in our analysis .
we take account of 0@xmath0.1 , i.e. , the relative astrometric uncertainty reported by the _ chandra _ calibration team , as systematic errors in the following proper - motion measurements .
figure [ fig : image ] _ right _ shows a difference image between two epochs after being registered and normalized to match the count rates in the two epochs .
we clearly see a signature of the expansion as positive emission ( seen as white in the figure ) with negative emission ( seen as black in the figure ) .
note that the horizontal stripes seen in the northern rim of the remnant are due to bad columns on the acis - s3 chip . to measure proper - motions of the forward shocks of the remnant , we focus on 14 rectangular regions at the edge of the x - ray image ( see , fig . [
fig : image ] _ left _ ) .
we then project the image into one dimension so that we generate one - dimensional profile along perpendicular direction to the shock motion ( hereafter , radial profile ) .
each bin of the radial profile is spaced by 0@xmath0.25 .
we adjust the position angle for each rectangular region as tangential as possible to the shock front in the following way .
we generate radial profiles for position angle with trial angles of 2@xmath9 steps . for each trial position angle , we calculate @xmath10 where @xmath11 is the intensity in each bin , @xmath12 .
the position angle with the largest value of @xmath13 represents the most tangential angle to the shock front .
the 14 regions with the `` best '' position angles are shown in fig .
[ fig : image ] _ left_. we plot example radial profiles from reg-4 and reg-14 in fig .
[ fig : profiles ] , from which we can see apparent shifts between the two epochs . to quantitatively measure the shifts , the first - epoch profile is shifted in radius with respect to the second - epoch profile , and @xmath14 is calculated from the difference between the two profiles at each shift position ( e.g. , katsuda et al .
2008 ) . in this way
, we obtain @xmath14 profiles as a function of shift positions . by applying a quadratic function for the @xmath14 profile , we measure the best - shift position where the minimum @xmath14-value ( @xmath15 ) occurs . 90% statistical uncertainties on the best - shift
are calculated using a criteria of @xmath16 .
[ tab : summary ] summarizes the best - shift positions between the two observations , @xmath17 per degrees of freedom , and proper motions for all the regions indicated in fig .
[ fig : image ] _ left_. the azimuthal angle for each region , which is measured counterclockwisely from the radio center at @xmath18 17@xmath1930@xmath2041@xmath21.5 , @xmath22 ( j2000 ; matsui et al . 1984 ) , is also listed in the table .
we find that the proper - motions vary from location to location .
plotting the proper - motion derived in each region as a function of azimuthal angle in fig .
[ fig : azimuth ] , we find a trend that the proper - motions derived in the northern regions ( i.e. , regs-1 , 2 , 13 , and 14 ) are slower than those derived in the rest of the regions .
we have measured proper - motions of the forward shocks on overall rims of kepler s snr . if we combine them with the shock velocities , the distance to the remnant can be determined .
the velocities of the forward shocks associated with balmer - dominated filaments , which were located at the northern rim and the central portion of the remnant , were determined to be 16702800kmsec@xmath2 ( fesen et al .
1989 ) or 15502000kmsec@xmath2 ( blair et al . 1991 ) from their h@xmath23 emission line widths . under the assumption of little or no temperature equilibration between electrons and protons , sankrit et al .
( 2005 ) determined the best - estimated shock velocity to be 1660@xmath1120kmsec@xmath2 .
since the best - estimated shock velocity represents the average velocity of the forward shocks with balmer - dominated filaments seen in the northern and the central portion of the remnant , we should combine it with an error - weighted mean proper - motion measured in the northern regions ( i.e. , regs-1 , 2 , 13 , 14 ) .
then , the best - estimated distance to the remnant is determined to be 3.3 ( @xmath24/1660kmsec@xmath2)(@xmath25/0@xmath0.107 yr@xmath2)@xmath2 kpc . we can estimate a distance range of 2.94.9kpc to the remnant , considering the variation of the proper - motions derived in the four northern regions of 0@xmath0.0760@xmath0.11 yr@xmath2 as well as the uncertainty of the shock velocity . while the best - estimated distance determined here
is less than @xmath65kpc ( reynoso & goss 1999 ) , it is well within the values previously measured based on the combination of the proper - motion and the shock - velocity of the balmer - dominated filaments : from 2.9kpc ( blair et al .
1991 ) to 3.9kpc ( sankrit et al .
2005 ) .
we find velocity asymmetries of the forward shocks of kepler s snr : shock velocities on the northern rim are 1.53 times slower than those on the other rims .
if we assume the pressure equilibrium in the remnant , the velocity contrast of 1.53 requires a density contrast of @xmath629 .
recently , blair et al .
( 2007 ) estimated that the preshock density in the north of the remnant is @xmath649 times higher than that in the south , based on brightness variations observed between the northern and southern rims of the remnant at 24@xmath25 m .
therefore , the slower expansion observed on the northern rim than those on the rest of the rims seems to be well explained by the density contrast suggested from the observation at 24@xmath25 m .
it is interesting that kepler s snr appears quite round in spite of the asymmetric velocities of the forward shocks .
one possibility to explain this feature is that the forward shock encountered a dense gas on the northern rim so recently that we can hardly see apparent deceleration of the shock from morphological point of view .
however , there have been no reports of such a very recent shock deceleration so far .
( in addition , we can not obtain at least strong evidence that the forward shock on the northwestern rim shows recent significant deceleration ; sankrit et al .
[ 2005 ] measured a proper - motion of a balmer - dominated filament positionally coincident with the forward shock in reg-13 from observations performed on two epochs in 1987 and 2003 to be 0@xmath0.089@xmath10@xmath0.009 yr@xmath2 that is consistent with our estimation of the proper - motion of 0@xmath0.076 [ @xmath10@xmath0.032 @xmath10@xmath0.016 ] yr@xmath2 determined in between 2000 and 2006 ) .
we propose another possibility that the expansion center of the remnant is located at a relatively northern position compared to the geometric center determined by the entire remnant .
in fact , the outer edges of the x - ray structure seem to be outlined by two ( ideally concentric ) circles whose centers are located at the north of the radio center : one with a relatively small radius outlines the northern - half edge of the remnant , whereas the other with a relatively large radius outlines the southern - half edge .
we estimate the best - fit circle for either the northern - half edge or the southern - half edge independently . here , we define the northern half in a range of azimuthal angles from @xmath2650@xmath9 ( or 310@xmath9 ) to 45@xmath9 , whereas the southern half in a range of azimuthal angles from 95@xmath9 to 258@xmath9 , such that the northern half covers the regions with proper - motions of @xmath60@xmath0.1 yr@xmath2 , whereas the southern half covers the other regions with proper - motions of above @xmath60@xmath0.2 yr@xmath2 .
we define the edge of the x - ray extent ( hereafter , x - ray boundary ) as contours of 5 counts per 0@xmath0.492-sided pixel in the second - epoch 0.38.0kev band image .
we ignore x - ray boundaries showing apparent deviations from circular curvatures , in order not to yield misleading geometric centers and radii .
the x - ray boundaries used to estimate the best - fit circles are drawn by white curves ( contours ) in fig . [ fig : center ] . assuming the geometric center
, we calculate the distance , @xmath27 , between each pixel , @xmath12 , on the x - ray boundaries and the geometric center . for various trial geometric centers ,
we calculate @xmath28 where @xmath29 is a variable parameter representing a radius .
we can derive the best - fit radius , @xmath29 , as well as the geometric center at the minimum of the @xmath30-value .
the best - fit circles representing the x - ray boundaries for the northern and southern halves are centered at @xmath18 17@xmath1930@xmath2041@xmath21.4 , @xmath31 ( j2000 ) with a radius of 93@xmath0 , and at @xmath18 17@xmath1930@xmath3241@xmath21.9 , @xmath33 ( j2000 ) with a radius of 120@xmath0 , respectively .
parts of these two circles are indicated in fig .
[ fig : center ] as white dashed pie .
we see that both geometric centers estimated are shifted by about 5@xmath0 toward the north of the remnant from the radio center ( see , fig .
[ fig : center ] ) , which results in a smaller radius for the circle representing the northern - half x - ray boundary than that for the southern - half x - ray boundary ; the ratio of the radius is derived to be about 3:4 .
although we can not derive uncertainties on the center positions and radii in the least square method used above , we might estimate uncertainties on these parameters from the @xmath14 method by introducing fake errors on the data ( @xmath27 ) .
we introduce the fake errors of 1% for the northern half and 3.5% for the southern half , respectively , so that we can derive the reduced @xmath14-value of @xmath61 .
the 90% uncertainties , i.e. , @xmath34 as appropriate for three interesting parameters , are estimated to be @xmath10@xmath0.5 or @xmath11@xmath0.5 ( in right ascension ) , and @xmath11@xmath0.5 or @xmath12@xmath0 ( in declination ) for the northern or southern halves , respectively . therefore , the derived offset of @xmath65@xmath0 from the radio center seems to be significant , although we can not strongly state the significance without knowing the uncertainty of the radio center .
hydrodynamic simulations of a remnant expanding into a medium with a density gradient ( dohm - palmer & jones 1996 ) show that the shock outline remains roughly circular , while the center of the best - fit curvature can move away from the true explosion location by as much as 10 15% of the remnant radius .
the offsets between geometric centers estimated here and the radio center ( matsui et al . 1984 ) are roughly 5% of the radius .
therefore , from theoretical point of view , our newly determined geometric centers can be possible true explosion locations of kepler s snr .
we believe that the true explosion point is around the geometric centers estimated here .
we consider the expansion center of kepler s snr at @xmath3517@xmath1930@xmath2041@xmath21.6 , @xmath36 ( j2000 ) that is the center point between the two center points of the circles representing the northern - half and southern - half x - ray boundaries .
then , the expansion rate can be calculated by dividing the proper - motion value in each region by the distance between the shock front and the expansion center .
combined with the age of the remnant of 400 yr , the expansion index , @xmath4 , is also calculated , where the expansion of the forward shock of snrs can be expressed as @xmath37 ( i.e. , the remnant s radius is assumed to evolve as a power law with age ; see , e.g. , woltjer 1972 ) . table . [
tab : param ] summarizes these parameters and fig .
[ fig : azimuth2 ] shows the expansion indices as a function of azimuthal angle .
snrs cease being in pure free expansion ( @xmath38 ) after a few years , as they interact with circumstellar or interstellar gas .
then , a reverse shock into the ejecta is formed , and remnants evolve in what is usually called an ejecta - driven phase . in spherical symmetry ,
if both the ejecta and the csm have power - law density profiles characterized by @xmath39 and @xmath40 , respectively , the evolution becomes self - similar and is given by @xmath41 , i.e. , the expansion index , @xmath4 , can be written as @xmath42 ( e.g. , chevalier 1982 ) . here
, the value of @xmath43 is 0 for a uniform csm , and is 2 for a constant wind velocity from the progenitor star . in general , the @xmath43-value is expected to be 2 for core - collapse sne , since massive stars which results in core - collapse sne produce stellar wind before sn explosions , while both @xmath44 and @xmath45 can happen for type - ia sne as mentioned in section 1 . as for @xmath46-values , @xmath47 is expected for a core - collapse origin ( e.g. , chevalier 1992 ) , while @xmath48 for a type - ia origin ( e.g. , chevalier 1982 ) .
therefore , for core - collapse sne , the value of @xmath4 is expected to be greater than 6/7 ( = 0.86 ) .
on the other hand , for type - ia sne , the value of @xmath4 ranges from 0.4 to 0.8 .
our measured @xmath4-values at all regions except for regions 6 and 13 range from 0.47 to 0.82 , which is consistent with that expected from type - ia sne .
we find significant variations of @xmath4-values in this remnant , which suggests complicated csm structures around the remnant .
it should be remarked that the northern rim shows slower expansions than the southern rim does .
the north - south density asymmetry of the csm suggested from variations of surface brightness results in the variation of @xmath4-values between the northern rim and the southern rim .
it is worth noting how the velocity difference of the forward shock affects spectral features . as already noticed by _ xmm - newton _
( cassam - chena@xmath49 et al .
2004 ) and _ chandra _ ( reynolds et al .
2007 ) observations , a spectrum extracted around reg-6 on the southeastern rim is non - thermal ( synchrotron ) in origin , whereas a spectrum around reg-13 on the northwestern rim is thermal in origin .
we can clearly see the spectral difference in fig .
[ fig : spec ] .
this is considered as a result that the faster shock ( 4700kmsec@xmath2 at a distance of 3.3kpc ) as well as the lower ambient density suggested by lower surface brightness in reg-6 produces the synchrotron emission more efficiently than the slower ( 1200kmsec@xmath2 at a distance of 3.3kpc ) shock as well as higher ambient density in reg-13 does .
we should note previous x - ray expansion measurements based on _ einstein _ and _ rosat _ observations performed by hughes ( 1999 ) .
the mean expansion rates in the entire remnant was derived to be @xmath60.24% yr@xmath2 .
this value is larger than that estimated in our analysis ; only one region ( reg-6 ) shows such a rapid expansion .
furthermore , he measured expansion rates as a function of azimuthal angle , by comparing long radial profiles from the geometric center to the x - ray boundaries between two _ rosat _ hri observations .
the expansion rates measured in the northern portion of the remnant did not show lower values than those in the other portions .
this also conflicts to our results .
these discrepancies might come from the different method between hughes ( 1999 ) and this work .
hughes ( 1999 ) measured radially averaged proper - motions of the remnant , on the other hand , we measure proper - motions for the very edge of the remnant , i.e. , the forward shocks themselves .
therefore , the faster expansion rates derived in hughes ( 1999 ) than those in this work suggests that plasmas in the inner remnant show larger expansion rates than those of the forward shocks
. such a situation might indicate recent rapid deceleration of the forward shocks .
however , as mentioned above , we have not yet observed ( at least strong ) such indications so far .
further detailed proper - motion measurements in the inner remnant are strongly required to reveal the reason of the discrepancies between the expansion rate by hughes ( 1999 ) and that in this work .
we have measured proper - motions of the forward shocks on the overall rims of kepler s snr , using the archival _ chandra _ data .
the expansion indices measured at various parts of the rim supports the type - ia sn which has the situation that the ejecta and the csm , respectively , have power - law density profiles with indices of 57 and 02 rather than the core - collapse sn .
we find that the shock velocities are asymmetric : the shock velocities on the northern rim are 1.53 times slower than those on the rest of the remnant .
we attribute this asymmetry to the density inhomogeneities of the csm surrounding the remnant .
the shape of the x - ray boundary of the remnant as well as the inhomogeneous csm structures lead us to consider that the expansion center is located at @xmath65@xmath0 offset in the north of the radio center .
this work is partly supported by a grant - in - aid for scientific research by the ministry of education , culture , sports , science and technology ( 16002004 ) .
is supported by jsps research fellowship for young scientists .
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35 , 1027 schaefer , b. e. 1994 , apj , 426 , 493 van den bergh , s. , & kamper , k. w. 1977 , apj , 218 , 617 woltjer , l. 1972 , ara&a , 10 , 129 reg-1 & 16 & 1.68 & 0.63 ( @xmath10.09 @xmath10.10 ) & 0.109 ( @xmath10.013 @xmath10.016 ) + reg-2 & 32 & 0.54 & 0.66 ( @xmath10.08 @xmath10.10 ) & 0.104 ( @xmath10.015 @xmath10.016 ) + reg-3 & 75 & 0.85 & 0.91 ( @xmath10.11 @xmath10.10 ) & 0.149 ( @xmath10.017 @xmath10.016 ) + reg-4 & 96 & 1.47 & 1.16 ( @xmath10.09 @xmath10.10 ) & 0.191 ( @xmath10.015 @xmath10.016 ) + reg-5 & 102 & 2.27 & 1.26 ( @xmath10.10 @xmath10.10 ) & 0.206 ( @xmath10.016 @xmath10.016 ) + reg-6 & 135 & 1.56 & 1.84 ( @xmath10.29 @xmath10.10 ) & 0.302 ( @xmath10.048 @xmath10.016 ) + reg-7 & 155 & 1.71 & 1.08 ( @xmath10.18 @xmath10.10 ) & 0.178 ( @xmath10.030 @xmath10.016 ) + reg-8 & 172 & 1.39 & 1.48 ( @xmath10.16 @xmath10.10 ) & 0.242 ( @xmath10.025 @xmath10.016 ) + reg-9 & 230 & 1.80 & 1.25 ( @xmath10.13 @xmath10.10 ) & 0.206 ( @xmath10.021 @xmath10.016 ) + reg-10 & 242 & 1.00 & 0.99 ( @xmath10.13 @xmath10.10 ) & 0.162 ( @xmath10.022 @xmath10.016 ) + reg-11 & 250 & 1.25 & 1.29 ( @xmath10.24 @xmath10.10 ) & 0.212 ( @xmath10.040 @xmath10.016 ) + reg-12 & 258 & 1.06 & 1.10 ( @xmath10.17 @xmath10.10 ) & 0.180 ( @xmath10.027 @xmath10.016 ) + reg-13 & 319 & 0.89 & 0.46 ( @xmath10.19 @xmath10.10 ) & 0.076 ( @xmath10.032 @xmath10.016 ) + reg-14 & 345 & 1.06 & 0.70 ( @xmath10.08 @xmath10.10 ) & 0.114 ( @xmath10.014 @xmath10.016 ) + reg-1 & 16 & 0.12 ( @xmath10.01 @xmath10.02 ) & 0.49 ( @xmath10.06 @xmath10.07 ) & 0.45 + reg-2 & 32 & 0.12 ( @xmath10.02 @xmath10.02 ) & 0.47 ( @xmath10.07 @xmath10.07 ) & 0.45 + reg-3 & 75 & 0.16 ( @xmath10.02 @xmath10.02 ) & 0.63 ( @xmath10.07 @xmath10.07 ) & 0.65 + reg-4 & 96 & 0.17 ( @xmath10.01 @xmath10.01 ) & 0.68 ( @xmath10.05 @xmath10.06 ) & + reg-5 & 102 & 0.17 ( @xmath10.01 @xmath10.01 ) & 0.70 ( @xmath10.05 @xmath10.05 ) & + reg-6 & 135 & 0.25 ( @xmath10.04 @xmath10.01 ) & 0.98 ( @xmath10.16 @xmath10.05 ) & + reg-7 & 155 & 0.16 ( @xmath10.03 @xmath10.01 ) & 0.63 ( @xmath10.11 @xmath10.06 ) & + reg-8 & 172 & 0.20 ( @xmath10.02 @xmath10.01 ) & 0.82 ( @xmath10.08 @xmath10.05 ) & + reg-9 & 230 & 0.18 ( @xmath10.02 @xmath10.01 ) & 0.71 ( @xmath10.07 @xmath10.06 ) & + reg-10 & 242 & 0.14 ( @xmath10.02 @xmath10.01 ) & 0.55 ( @xmath10.08 @xmath10.06 ) & 0.55 + reg-11 & 250 & 0.18 ( @xmath10.03 @xmath10.01 ) & 0.72 ( @xmath10.14 @xmath10.05 ) & 0.55 + reg-12 & 258 & 0.16 ( @xmath10.02 @xmath10.01 ) & 0.62 ( @xmath10.09 @xmath10.06 ) & 0.55 + reg-13 & 319 & 0.08 ( @xmath10.04 @xmath10.02 ) & 0.34 ( @xmath10.14 @xmath10.07 ) & 0.35 + reg-14 & 345 & 0.12 ( @xmath10.02 @xmath10.02 ) & 0.50 ( @xmath10.06 @xmath10.07 ) & 0.35 + [ tab : param ] .492 and has been smoothed by gaussian kernel of @xmath50.984 .
the intensity scale is logarithmic .
we measure proper - motions of the forward shock in 14 regions indicated as rectangules ( from reg-1 to reg-14 ) . _
right _ : linearly scaled difference ( 2006@xmath262000 ) image between the two epochs . ]
.25 scale derived for reg-4 .
data points with circles and triangles represent the first- and the second - epoch observations , respectively .
the shock motion is in the left direction .
_ right _ : same as _ left _ but for reg-14 . ] | the x - ray structure of kepler s supernova remnant shows a rounded shape delineated by forward shocks .
we measure proper - motions of the forward shocks on overall rims of the remnant , by using archival _
chandra _ data taken in two epochs with time difference of 6.09 yr . the proper - motions of the forward shocks on the northern rim are measured to be 0@xmath0.076 ( @xmath10@xmath0.032 @xmath10@xmath0.016 ) 0@xmath0.11 ( @xmath10@xmath0.014 @xmath10@xmath0.016 ) yr@xmath2 , while those on the rest of the rims are measured to be 0@xmath0.15 ( @xmath10@xmath0.017 @xmath10@xmath0.016 ) 0@xmath0.30 ( @xmath10@xmath0.048 @xmath10@xmath0.016 ) yr@xmath2 , here the first - term errors are statistical uncertainties and the second - term errors are systematic uncertainties . combining the best - estimated shock velocity of 1660@xmath1120kmsec@xmath2 measured for balmer - dominated filaments in the northern and central portions of the remnant ( sankrit et al .
2005 ) with the proper - motions derived for the forward shocks on the northern rim , we estimate the distance of 3.3@xmath3kpc to the remnant .
we measure the expansion indices , @xmath4 , ( defined as @xmath5 ) to be 0.470.82 for most of the rims .
these values are consistent with those expected in type - ia sn explosion models , in which the ejecta and the circumstellar medium have power - law density profiles whose indices are 57 and 02 , respectively .
also , we shuold note the slower expansion on the northern rim than that on the southern rim .
this is likely caused by the inhomogeneous circumstellar medium ; the density of the circumstellar medium is higher in the north than that in the south of the remnant .
the newly estimated geometric center , around which we believe the explosion point exists , is located at @xmath65@xmath0 offset in the north of the radio center . |
Dorothy Parvaz, who disappeared on assignment in Syria 19 days ago, was sent back to Doha by Iranian authorities.
Parvaz describes her "terrifying" experiences while detained in Syria. Al Jazeera has confirmed the release of its journalist, Dorothy Parvaz, who was detained in Syria upon her arrival in Damascus while on an assignment, and then deported to Iran. Parvaz landed in Doha, Qatar on May 18 on a flight from Iran. An Al Jazeera spokesman said: "I'm delighted to let you know that Dorothy Parvaz has been released and is safe and well and back with us in Doha. She has been in contact with her family, and we are with her now to find out more about her ordeal over the last 19 days." Her fiancé Todd Barker, posted on Facebook: "She is safe in Doha and will be coming to Vancouver BC soon. We can't wait to see her." Barker, who is planning to marry Parvaz this summer, was with her family when he heard the news. He thanked US and Canadian officials, the Committee to Protect Journalists (CPJ), the international Committee of the Red Cross (ICRC) and all of those who had rallied in support of his fiancé. Barker said he was grateful to Al Jazeera for the network's efforts to obtain Parvaz's release.
"It's been a pleasure working with them, as much as it can be," he said. "They were working like nobodies' business on it and we're just ecstatic." 'Terrifying experience' Parvaz was detained as soon as she had landed in Damascus on April 29 to cover the unrest sweeping the country. Syrian authorities then deported her to Iran on May 1. "I was handcuffed repeatedly, blindfolded, taken to a courtyard and just left to hear these men being beaten ... it was an overall terrifying experience" - Dorothy Parvaz, on her captivity in Syria. On her return, Parvaz said she had a "terrifying experience" while being held in Syria. "I was in the Syrian detention centre for three days and what I heard were just savage beatings. I didn't know what these men had done, one agent said that two of them were responsible for murders in or near Deraa. "I was handcuffed repeatedly, blindfolded, taken to a courtyard and just left to hear these men being beaten.They all sounded very young, they all sounded to be in their late teens or early twenties. So it was an overall terrifying experience," she said. She, however, was treated well in Iran. "Actually all told, it was relatively fair. The people there [Iran] treated me with respect. I had a clean room, I had a physical check-up with the doctor as soon as I showed up. All of my questions were answered as much as they could be. "The women who looked after me at the women’s detention centre were extraordinarily kind, twice a day I was taken out for fresh air. I’m a vegetarian, that diet was adhered to, any medication I needed." Dorothy is an experienced journalist who joined Al Jazeera in 2010. She graduated from the University of British Columbia, completed a masters degree in Arizona, and held journalism fellowships at both Harvard and Cambridge. She previously worked as a columnist and feature writer for the Seattle Post-Intelligencer. ||||| TRIPOLI, Libya — Four foreign journalists held for several weeks by the Libyan government were released on Wednesday and taken to a Tripoli hotel, with government officials saying they would be provided with transport to a border crossing with Tunisia on Thursday.
In addition, a journalist from Al Jazeera who had been detained in Syria and then held in Iran for almost three weeks has been released, her family and the network said Wednesday.
That journalist, Dorothy Parvaz, disappeared in Syria last month while covering antigovernment protests. Her whereabouts were unknown until Syrian officials acknowledged a week ago that they had sent her to Iran shortly after detaining her.
The journalists released in Tripoli were James Foley and Clare Morgana Gillis, who are American; Manu Brabo, who is from Spain; and Nigel Chandler from Britain.
Libyan officials said they had no information about a fifth journalist who has been missing for weeks, Anton Hammerl, a freelance photographer who holds South African and Austrian citizenship.
The decision to release the four, after weeks of uncertainty about their safety and repeated assurances that they would be freed, appeared to be linked to a new effort by Col. Muammar el-Qaddafi’s government to find a way out of its increasing isolation through diplomatic negotiations.
That bid has been rebuffed by rebel officials and by Western governments backing the NATO bombing campaign, who have said Colonel Qaddafi must step down as a condition for any talks.
Libyan officials said a judge in Tripoli had sentenced the four journalists to suspended one-year jail terms and fined them 200 Libyan dinars each — about $165 at the official exchange rate — for entering the country illegally.
The officials said the charges stemmed from the journalists’ entering rebel-held territory in eastern Libya without the required visas.
Emphasizing the government’s good will in the affair, as Libyan officials presented it, Moussa Ibrahim, the chief government spokesman, said the released journalists were welcome to remain in Libya and resume their reporting from Tripoli if they chose.
But from their brief conversations with other reporters, the four appeared to have decided to leave the country as soon as possible.
The journalists appeared tired Wednesday when they arrived at the Tripoli hotel that is the headquarters for the foreign news media covering the conflict, but Ms. Gillis, a freelance reporter who has written for The Atlantic magazine and USA Today, said they were in good health.
Mr. Brabo, a freelance photographer, said he, Ms. Gillis and Mr. Foley, a freelance writer who has worked for the Boston-based news agency GlobalPost, were arrested April 5 when they moved from rebel-held positions around Adjdabiya and ran into government troops a few miles outside Brega, an oil town 500 miles east of Tripoli.
It was not immediately clear where Mr. Chandler, who has worked as a freelance cameraman for the BBC and other TV networks, was arrested.
Mr. Brabo said that his early experience in government hands, with Ms. Gillis and Mr. Foley, had been “unpleasant,” but that they had been treated well during later detention at a villa in Tripoli, where they were allowed visits by European diplomats.
In March, four journalists for The New York Times were detained under similar circumstances in eastern Libya. The four journalists — reporters Anthony Shadid and Stephen Farrell and photographers Tyler Hicks and Lynsey Addario — were released after six days. In an account of their experiences, the four said they had been abused by their Libyan captors. | – An al-Jazeera journalist has safely landed in Qatar, having been released by Iranian officials after being detained in Damascus last month. Al-Jazeera confirms that Dorothy Parvaz is "safe and well and back with us in Doha. She has been in contact with her family, and we are with her now to find out more about her ordeal over the last 19 days." Parvaz's whereabouts were unknown until last week, when Syrian officials disclosed that she had been sent to Iran because, they said, she had entered Syria using an expired Iranian passport, reports the New York Times. Fiance Todd Barker told the Canadian Press that she called him "out of the blue" as she was going through customs in Qatar. "I looked at my phone, saw it was her number and God, it was as unreal as the moment when I got the call that she hadn’t been contacted in 24 hours." Barker says she told him she was "treated very well, she was interrogated, but she's fine." |
there have been a lot of discussions about whether perturbative qcd ( pqcd ) is applicable to exclusive processes at currently available experimental energies [ 1 - 12 ] . in the example of the pion and proton form factors , isgur and
llewellyn smith @xcite noticed that in the energy region of a few gev the main contributions come from the end - point region @xmath7 ( @xmath8 is the fractional momentum carried by the parton ) where the running couple constant @xmath9 becomes large .
thereby perturbation expansion might be illegal .
recently this problem has been attacked and it is suggested that pqcd might be still applicable to the exclusive processes at currently experimental accessible regime of momentum transfer ( @xmath10 a few gev@xmath11 ) by using some techniques to cure the end - point problem [ 5 - 10 ] . huang and shen @xcite pointed out that the applicability of pqcd to the hadronic form factors is questionable only as momentum transfers being @xmath12gev@xmath11 by reanalyzing the contributions from the end - point region for the pion form factor .
li and sterman @xcite proposed a modified perturbation expression for the pion form factor by taking into account the customarily neglected partonic transverse momentum as well as sudakov correction .
they obtain a similar conclusion as @xcite : pqcd begins to be self - consistent at about @xmath13 .
more recently , ji , pang , and szczepaniak @xcite pointed out that the usual factorization perturbation expression for the pion form factor is derived from the light - cone time - order perturbative expansion , and the natural variable to make a separation of perturbative contributions from contributions intrinsic to the bound - state wave function itself is the light - cone energy rather than the gluon virtuality of the hard scattering amplitude @xmath14 .
they find that the legal " pqcd contribution defined by the light - cone energy cut becomes self - consistent at even much smaller @xmath3 region as compared to that defined by the gluon four - momentum square cut .
nevertheless , we notice that although most of the recently calculations [ 5 - 12 ] show that perturbative qcd is self - consistent and applicable to the exclusive processes at currently experimental accessible energy regions , the numerical predictions for the pion form factor are much smaller than the experimental data .
there are two possible explanations : one is that the non - perturbative contributions will dominate in this region ; the other is that the non - leading order contributions in perturbative expansions may be also important in this region . to make choice between the two possible explanations
one needs to analyse the non - leading contributions which come from higher - twist effect , higher order in @xmath9 , and higher fock states _ etc . _
field , gupta , otto , and chang @xcite pointed out that the contribution from the next - leading order in @xmath9 is about @xmath15 to the perturbative pion form factor . employing the modified factorization expression for the pion form factor proposed by li and sterman @xcite , refs . @xcite considered the transverse momentum effect in the wave function and found that the transverse momentum in the wave function play the role to suppress perturbative prediction .
thus it is necessary to calculate the other non - leading contributions such as that from higher twist effect and higher fock states .
one of the other sources which may provide non - leading perturbative contribution is the higher helicity components in the light - cone wave function @xcite .
the effects from higher helicity components ( or wigner rotation effect ) have been investigated in the description of pion properties at high energies @xcite as well as at low energies [ 15,18 - 21 ] and the same effect has been also applied to explain the proton spin crisis " @xcite . however , the calculations for the contributions coming from higher helicity components to the pion form factor in the high energy region are conflicting in literatures @xcite . ma and
huang @xcite pointed out that the higher helicity components provide a large _ enhancement _ for the perturbation prediction of the pion form factor and thus may provide the other fraction which is needed to fit the experimental data around @xmath16 gev@xmath11 .
more recently , wang and kisslinger @xcite also analysed this effect based on the modified perturbative approach . in their approach
this effect gives a large _ suppression _ for the pion form factor as compared to the prediction obtained in the original hard - scattering model in the @xmath3 domain where experimental data are available .
thereby they concluded that non - perturbative contributions dominate in this region .
@xcite and @xcite gave very different conclusions concerning the question whether the perturbative qcd contributions dominate or not in the available experimental energy region .
we point out that the conflict between the above works is due to the difference between the hard - scattering amplitudes for the higher helicity components adopted in refs .
@xcite and @xcite .
it is assumed in ref .
@xcite that the hard - scattering amplitude for the higher helicity components is the same as that for the ordinary helicity component , t_h^(_1+_2=1)=t_h^(_1+_2=0 ) = .
[ hsamh ] but the hard - scattering amplitude employed in ref .
@xcite is t_h^(_1+_2=1)=-t_h^(_1+_2=0 ) = - - .
[ hsakw ] it can be seen that the asymptotic ( @xmath17 ) behaviors of eqs .
( [ hsamh ] ) and ( [ hsakw ] ) are with _ opposite _ signs .
that is the reason that refs .
@xcite and @xcite gave _ opposite _ conclusions concerning the pqcd contributions from the higher helicity components in the experimental available @xmath3 region .
the purpose of this paper is to analyze the effect from the higher - helicity components of the pion wave function in the light - cone perturbative qcd and address the conflict between refs .
@xcite and @xcite . we first review and analyze the spin structure for the pion light - cone wave function and the necessity to take into account the higher helicity components in sec .
ii . then in sec .
iii we calculate the hard - scattering amplitude for the higher helicity components of the pion form factor .
we first explicitly show that the hard - scattering amplitude for the higher helicity components vanishes in the leading order @xmath18 as the parton intrinsic transverse momentum is taken into account , it is found that the asymptotic behavior of the hard - scattering amplitude for the higher helicity components is of order @xmath2 which differs from either eq .
( [ hsamh ] ) or eq .
( [ hsakw ] ) .
we conclude that the higher helicity components , though provide vanishingly small contributions to the perturbative pion form factor in the asymptotic limit @xmath19 , they should be considered in the available experimental energy region since they are next - to - leading order contributions .
iv is served as a summary .
the light - cone ( lc ) formalism @xcite provides a convenient framework for the relativistic description of hadrons in terms of quark and gluon degrees of freedom , and the application of pqcd to exclusive processes has mainly been developed in this formalism ( light - cone pqcd ) @xcite .
the essential feature of light - cone pqcd application to exclusive processes is that the amplitudes for these processes can be written as a convolution of hadron light - cone wave functions ( or quark distribution amplitudes ) for every hadron involved in the process with a hard - scattering amplitude @xmath14 .
thus light - cone wave function is an essential part : it determines the distributions of the quark and gluons entering the short distance sub - processes and provides the link between the long - distance non - perturbative and short distance perturbative physics . in principle , light - cone wave function can be computed from rigorous light - cone qcd .
unfortunately this task is very complex and difficult , and there is no exact solution up to now .
more practical and more convenient way is to connect light - cone wave function with the instant - form wave function which can be obtained by solving the bethe - salpeter equation with some approximations @xcite .
the connection for the spin space wave functions between the two formalisms are accomplished @xcite by the use of wigner rotation @xcite .
the connection for the momentum space wave functions become possible with the help of some ansatz such as the brodsky - huang - lepage prescription @xcite .
it should be emphasized that in order to connect the spin structures in two different frames correctly , it is necessary to consider wigner rotation effect .
as it is known , spin is essentially a relativistic notion associated with the space - time symmetry of poincar .
the conventional 3-vector spin * s * of a moving particle with finite mass @xmath20 and 4-momentum @xmath21 can be defined by transforming its pauli - lubnski 4-vector @xmath22 to its rest frame via a non - rotation lorentz boost @xmath23 which satisfies @xmath24 , by @xmath25 . under an arbitrary lorentz transformation ,
a particle state with spin @xmath26 and 4-momentum @xmath21 will transform to the state with spin @xmath27 and 4-momentum @xmath28 , =r_(**,p)*s * , p=**p , where @xmath29 is a pure rotation known as wigner rotation . when a composite system is transformed from one frame to another one
, the spin of each constituent will undergo a wigner rotation .
these spin rotations are not necessarily the same since the constituents have different internal motion . in consequence ,
the sum of the constituent s spin is not lorentz invariant .
hence , although the pion has only @xmath1 spin components in the rest frame of the pion , it may have @xmath0 spin components in the infinite - momentum frame ( light - cone formalism ) , where @xmath30 and @xmath31 are the quark and anti - quark helicities respectively .
one advantage of light - cone dynamics is that wigner rotation relating spin states in different frames is unity under a kinematic lorentz transformation . to obtain light - cone spin space wave function of the pion one can transform the ordinary instant - form su(6 ) quark model spin space wave function of the pion into light - cone dynamics @xcite . in the pion rest frame
@xmath32 , the instant - form spin space wave function of the pion is _ t=(_1^_2 ^ -_2^_1^)/ , [ spinor - inst ] in which @xmath33 are the two - component pauli spinors and @xmath34 , @xmath35 are 4-momenta for the two quarks respectively with @xmath36 . the instant - form spin states @xmath37 and the light - cone form spin states @xmath38 are related by a wigner rotation @xmath39 [ 15 - 21 ] , |j,_f=_s u_s^j |j , s_t . [ wigner - rotation ] this rotation is called as melosh rotation @xcite for spin-1/2 particles . applying transformation eq .
( [ wigner - rotation ] ) on the both sides of eq .
( [ spinor - inst ] ) one can obtain the spin space wave function of the pion in the infinite - momentum frame . transforming for the left side ( _ i.e. _ , the pion )
is simple since wigner rotation is unity . for the right side ( _ i.e. _ , the two spin-1/2 partons ) , each particle instant - form and light - cone form spin states are related by the melosh transformation , ^(t)&=&w[(q^++m)^(f)-q^r^(f ) ] ; + ^(t)&=&w[(q^++m)^(f)+q^l^(f ) ] , [ melosh - rotation ] where @xmath40^{-1/2}$ ] , @xmath41 , and @xmath42 .
then the light - cone spin space wave function of the pion reads _
f(x , * k*_)=__1,_2 c_0^f(x,*k * _ , _
1,_2 ) _ 1^_1(f)_2^_2(f ) .
[ spinor - lc ] when expressed in terms of the equal - time momentum @xmath43 , the spin component coefficients @xmath44 have the forms , c^f_0(x , q,,)&= & ; + c^f_0(x , q,,)&=&- ; + c^f_0(x , q,,)&= & ; [ coefficient1 ] + c^f_0(x , q,,)&= & .the equal - time momentum @xmath45 and the light - cone momentum @xmath46 can be connected according to the brodsky - huang - lepage prescription @xcite which is obtained by equating the off - shell propagators in the two frames , ccc xm & & ( q^0+q^3 ) ; + * k * _ & & * q * _ , [ relation ] in which @xmath47 is defined as @xmath48 from ( [ relation ] ) we have @xmath49 from eqs .
( [ coefficient1 ] ) , ( [ relation ] ) and ( [ mdefination ] ) the coefficients @xmath44 can be expressed in the light - cone momentum @xmath46 , c_0^f(x,*k*_,,)&= & ; + c_0^f(x,*k*_,,)&= & - ; + c_0^f(x,*k*_,,)&= & - ; [ coefficient2 ] + c_0^f(x,*k*_,,)&= & - .
@xmath44 satisfy the relation _ _ 1,_2c_0^f(x,*k*_,_1,_2 ) c_0^f(x,*k*_,_1,_2)=1 .
it can be seen explicitly from eqs .
( [ spinor - inst ] ) , ( [ spinor - lc ] ) and ( [ coefficient2 ] ) that the light - cone spin space wave function of the pion @xmath50 has higher helicity ( @xmath0 ) components besides the ordinary helicity ( @xmath1 ) component , while the instant - form spin space wave function of the pion , @xmath51 has only the ordinary helicity component .
notice that @xmath50 is also an eigen - state of the total spin operator @xmath52 in the light - cone formalism @xcite .
now the light - cone wave function for the lowest valence state of the pion can be expressed as @xcite @xmath53 where @xmath54 here @xmath55 is the momentum space wave function in the light - cone formalism .
the above result means that the light - cone spin of a composite particle is not directly the sum of its constituents light - cone spins but the sum of wigner rotated light - cone spins of the individual constituents .
a natural consequence is that in light - cone formalism a hadron s helicity is not necessarily equal to the sum of the quark s helicities , _
i.e. _ , @xmath56 .
this result is important for understanding the proton `` spin puzzle '' @xcite .
it has been shown @xcite that the relativistic su(6 ) quark model of the nucleon , supplemented with wigner rotation effect @xcite and the flavor asymmetry generated by the spin - spin interaction of the valence spectator quarks , could reproduce the observed ratio @xmath57 and the proton , neutron , and deuteron polarization asymmetries , @xmath58 , @xmath59 , @xmath60 .
if the intrinsic quark - antiquark pairs generated by the non - perturbative meson - baryon fluctuations in the nucleon sea are further taken into account , we could arrive at a consistent framework @xcite to understand a number of anomalies observed in the proton s structure : the origin of polarized strange quarks implied by the violation of the ellis - jaffe sum rule ; the flavor asymmetry of the nucleon sea implied by the violation of gottfried sum rule ; and the conflict between two different measurements of strange quark distributions .
the pion electromagnetic form factor can be expressed by the drell - yan - west formula @xcite , f(q^2)=_n,_i_j e_j ^*_n(x_i,*k*_,i,_i ) _
n(x_i,*k*_,i,_i ) , [ drell - yan ] where @xmath61 for the struck quark , @xmath62 for the spectator quarks , and @xmath63 is the electric charge of the struck quark . at higher momentum transfer ,
the pion form factor in the leading order can be given by @xcite f_(q^2)&=&^((1-x)q)(x,*k*_,_i ) t_h(x , y,*q*_,*k*_,*l * _ ) ^*^((1-y)q)(y,*l*_,_i ) + & = & ^((1-x)q)(x,*k * _ ) [ w_1 t_h^(_1+_2=0)(x , y,*q*_,*k * _ , * l * _ ) + & & + w_2 t_h^(_1+_2=1 ) ( x , y,*q*_,*k*_,*l * _ ) ] ^*^((1-y)q)(y,*l * _ ) [ fpion ] where @xmath64=dx\delta(1-x_1-x_2)$ ] , @xmath65={d^2{\bf k}_\perp}/{(16\pi^3)}$ ] , @xmath66 is the light - cone momentum space wave function of the valence fock state with a cut - off @xmath67 , @xmath14 are the hard - scattering amplitudes which can be calculated from the time - ordered diagrams in light - cone pqcd , and @xmath68 and @xmath69 are the factors from wigner rotation , _ 1&=&m/^1/2 ; + w_2&=&*k*__/^1/2 . in the derivation for eq .
( [ fpion ] ) we have applied the relations t_h^*()=t_h ( ) , t_h^*()=t_h ( ) . [ threlation ] after summing over all helicities , only the real part of each hard - scattering amplitude survives .
thereby there are only two independent hard - scattering amplitudes : t_h^(_1+_2=0)&= & ; + t_h^(_1+_2=1)&= & .
[ thdefination ] as @xmath70 , wigner rotation factors @xmath71 , @xmath72 , and eq . ( [ fpion ] ) reduces to the ordinary perturbation expression for the pion form factor . in more general situation , there is also contribution from the higher helicity components @xmath73 besides the hard - scattering amplitude @xmath74 from the ordinary helicity component of the pion .
notice that quark helicity is conserved at each vertex in @xmath14 in the limit of vanishing quark mass , since both photon and gluon are vector particles @xcite .
hence there is no hard - scattering amplitude with quark and antiquark helicities being changed .
@xmath74 has been calculated in cases when the intrinsic transverse momenta are neglected ( see for example @xcite ) and taken into account @xcite . the purpose of this paper is to calculate @xmath73 , _
i.e. _ , the contribution from the higher helicity components of the pion light - cone wave function . in the light - cone perturbative
qcd , there are six time - order diagrams as shown in fig . 1 which contribute to @xmath75 and @xmath76 .
the calculation rules for the light - cone pqcd can be found in literatures @xcite .
first , we neglect the intrinsic transverse momenta @xmath77 and @xmath78 .
the contribution of diagram ( a ) can be written as , t_h^(a)=tr + inst . , [ thalo ] where @xmath79 and @xmath80 are the energy denominators " , d_11=-_^2 , d_12=-_^2 , and @xmath81 is the sum of some spinors and @xmath82-matrix in light - cone pqcd , = ig^ d_ig^ .
by using eqs .
( [ threlation ] ) and ( [ thdefination ] ) , we need to calculate only the real part of @xmath81 which reads , = -g^2_^2 .
[ rtrlo ] the @xmath83 " part in eq .
( [ thalo ] ) represents the contribution from instantaneous diagram which is one feature of light - cone pqcd , = g^2 .
then the contribution from diagram ( a ) reads t_h^(a)=g^2 .
it is known that the contribution from each diagrams , for example @xmath84 , is itself not gauge - invariant , but the gauge - invariance will be satisfied when summing over all time - order diagrams ( a)-(f ) .
the contributions from the other diagrams can be calculated in a similar way .
observing that the term
@xmath81 " is the same for the diagrams ( a ) , ( b ) and ( c ) , and employing the following relations for the energy denominators " , d_22=d_12 , & & d_31=d_11 , + d_11=d_32+d_12 , & & d_21=-d_32=_^2 , we can sum over the contributions from diagrams ( a ) , ( b ) and ( c ) , t_h^(a+b+c)&=&tr -g^2 + & = & .
[ th - abc ] we point out that under transformation ( @xmath85 ) there is symmetry for the six diagrams , ( a , b , c ) ( d , e , f ) under ( xy ) . thus the contributions form diagrams ( d ) , ( e ) , and ( f ) are , t_h^(d+e+f)=. [ th - def ] from eqs .
( [ th - abc ] ) and ( [ th - def ] ) we can obtain the hard - scattering amplitude for the higher helicity components in the approximation neglecting parton intrinsic transverse momenta , t_h^(_1+_2=1)(x , y,*q*_)= t_h^(a+b+c)+t_h^(d+e+f)=0 . [ th1nkl ] eq .
( [ th1nkl ] ) shows that there is no contribution from the higher helicity components for the pion form factor in the leading order @xmath18 ( or the intrinsic transverse momenta being neglected ) ; which is in agreement with the early result obtained by brodsky and lepage @xcite .
now we take into account the parton intrinsic transverse momenta @xmath77 and @xmath78 . then
@xmath81 " means = ig^ d_ig^ and = [ 2(x_1y_2+y_1x_2 ) ] .
[ rtr1 ] the energy denominators " are d_11=- - , & & d_12=- ; + d_21=- + , & & d_22=d_12 ; + [ drelation1 ] d_32=- - , & & d_31=d_11 . using the symmetry ( a , b , c ) ( d , e , f ) \ { lcr x & & y + * k * _ & & -*l * _ } [ symmetry ] we get , t_h^(_1+_2=1)(x , y,*q*_,*k * _ , * l*_)&= & rtr + & & + + \
{ lcr x&&y + * k*_&&-*l * _ } .
[ th1 ] in the above calculation we have neglected the quark masses since it is current quark masses " that should appear in perturbative calculation .
the pionic mass can also be neglected in pqcd calculation . to simplify eq .
( [ th1 ] ) , we adopt the following two prescriptions : 1 ) it is pointed out in ref
. @xcite that as one concerns with the effect from intrinsic transverse momenta the terms proportional to the bound energies " of the pions in the initial and final states _
i.e. _ @xmath86 and @xmath87 can be ignored to avoid the involvement of the higher fock states contributions and @xmath78 are included , it is necessary to take into account the contributions from higher fock states to satisfy the gauge - invariance , since the covariant derivative @xmath88 makes both transverse momenta @xmath77 , @xmath78 and the transverse gauge degree @xmath89 be of the same order @xcite . ] . neglecting these terms in the energy denominators " , we have , t_h^(_1+_2=1)(x , y,*q*_,*k * _ , * l*_)&= & + & & + \ { lcc x&&y + * k*_&&-*l * _ } .
[ th1-approximation1 ] 2 ) notice that in the factorization expression for the pion form factor eq .
( [ fpion ] ) , we have @xmath90 and @xmath91 .
hence when calculating to the next - to - leading order in @xmath92 for @xmath14 , we can neglect the terms such as @xmath93 , @xmath93 and @xmath94 in the both the energy denominators " and @xmath95 " .
then we get t_h^(_1+_2=1)(x , y,*q*_,*k * _ , * l*_)&= & + & & + \ { lcc x&&y + * k*_&&-*l * _ } .
[ th1-approximation2 ] as the intrinsic transverse momenta @xmath77 and @xmath78 are neglected ( or in the asymptotic limit @xmath96 ) , eqs .
( [ th1 ] ) , ( [ th1-approximation1 ] ) , and ( [ th1-approximation2 ] ) reduce to eq .
( [ th1nkl ] ) , _ i.e. _ , the hard - scattering amplitude for the higher helicity components goes to zero
. it can be found from eqs .
( [ th1-approximation1 ] ) and ( [ th1-approximation2 ] ) that the leading contribution of the hard - scattering amplitude for the higher helicity components is of order @xmath2 which is next - to - leading contribution compared to the contribution coming from the ordinary helicity component , but it may give sizable contributions to the pion form factor in the intermediate energy region .
we also notice that ( [ th1-approximation1 ] ) and eq .
( [ th1-approximation2 ] ) differ to either eq .
( [ hsamh ] ) or eq .
( [ hsakw ] ) , hence the calculations in neither ref .
@xcite nor ref .
@xcite is reliable .
it is necessary to re - consider the pqcd contributions from the higher helicity components based on proper hard - scattering amplitude derived from theory at the energy scale where the current experiments are accessible .
the quantitative predictions depend on numerical calculation which involves 6-dimensional integral with tedious technical details , and will be given elsewhere .
the light - cone formalism provides a convenient framework for the relativistic description of hadrons in terms of quark and gluon degrees of freedom , and the application of perturbative qcd to exclusive processes has mainly been developed in this formalism . in order to obtain correct spin structure for the hadron wave function in the light - cone formalism from the instant - form wave function , the relativistic effect due to wigner rotation
should be taken into account .
consequently , in the light - cone formalism , there are higher helicity ( @xmath0 ) components in the spin space wave function besides the usual helicity ( @xmath1 ) components .
we give the hard scattering amplitude for the higher helicity components in the perturbative calculation for the pion form factor .
it is found that the hard - scattering amplitude for the higher helicity components is of order @xmath2 , which is vanishingly small compared to that of the ordinary helicity components at very high @xmath3 but should be considered in the @xmath3 region where experimental data are available . 99 s. j. brodsky and g. p. lepage , ; phys . lett . *
87b * , 359 ( 1979 ) ; g.p .
lepage and s.j .
brodsky , .
n. isgur and c. h. llewellyn smith , ; ; .
a. v. radyushkin , . c .-
ji , a. f. sill , and r. m. lombdar - nelson , ; c .- r .
ji and f. amiri , _ ibid . _ .
t. huang and q. x. sheng , .
h. n. li and g. sterman , . h. n. li , .
r. jacob and p. kroll , ; f.g .
cao and t. huang , preprint hep - ph/9612233 .
f. g. cao , t. huang , and c. w. luo , .
f. g. cao , t.huang , and b. q. ma , .
ji , a. pang , and a. szczepaniak , .
r. d. field , r. gupta , s. otto , and l. chang .
t. huang , b. q. ma , and q. x. shen , phys .
d * 49 * , 1490 ( 1994 ) .
b. q. ma , .
ma and t.huang , j. phys .
g * 21 * , 765 ( 1995 ) . s. w. wang and l. s. kisslinger , .
z. dziembowski , .
p. l. chung , f. coester , and w. n. polyzou , .
l. s. kisslinger and s. w. wang , ; o. c. jacob and l. s. kisslinger , ; l. s. kisslinger and s. w. wang , carnegie - mellon preprint ( 1994 ) , hep - ph/9403261 .
f. schlumpf , phys . rev . *
d 50 * , 6895 ( 1994 ) .
b. q. ma , j. phys .
g * 17 * , l53 ( 1991 ) ; b. q. ma and q. r. zhang , ; s. j. brodsky and f. schlumpf , . b. q. ma , .
see , e.g. , j. b. kogut and d. e. soper , phys .
* d 1 * , 2901 ( 1970 ) ; j. b. bjorken , j. b. kogut , and d. e. soper , _ ibid .
_ * 3 * , 1328 ( 1971 ) ; s. j. brodsky , r. roskies , and r. suaya , _ ibid . _ * 8 * , 4574 ( 1973 ) .
s. j. brodsky and g. p. lepage , _ perturbative quantum chromodynamics _ , edited by a. h. mueller ( singapore , world scientific , 1989 ) , p. 93 .
s. j. brodsky , t. huang , and g. p. lepage , in _ particles and fields-2 _ , proceedings of the banff summer institute , banff , alberta , 1981 , edited by a. z. capri and a. n. kamal ( plenum , new york,1983 ) , p. 143 ; g. p. lepage , s. j. brodsky , t. huang , and p. b. mackenize , _ ibid .
_ , p. 83 ; t. huang , in _ proceedings of xxth international conference on high energy physics _ ,
madison , wisconsin , 1980 , edited by l. durand and l. g. pondrom , aip con .
69 ( aip , new york , 1981 ) , p. 1000 .
e. wigner , ann . math . * 40 * , 149 ( 1939 ) .
j. melosh , phys .
d * 9 * , 1095 ( 1974 ) .
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yan , ; g. west , .
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1 . leading order time - order diagrams contributing to the hard scattering amplitude for the higher helicity @xmath97 components of the pion in the perturbative calculation for the pion form factor , where @xmath98 , @xmath99 , @xmath100 , and @xmath101 , and the momenta are expressed in the light - cone variables @xmath102 . as usual
the momentum of the pion in the initial state is taken to be @xmath103 and the momentum of the photon is @xmath104 with @xmath105 . | for obtaining the spin space wave function of the pion meson in the light - cone formalism from the naive quark model , it is necessary to take into account wigner rotation .
consequently there are higher helicity ( @xmath0 ) components in the light - cone spin space wave function of the pion besides the usual helicity ( @xmath1 ) components . for the pion electromagnetic form factor
, we calculate the hard - scattering amplitude for the higher helicity components in the light - cone perturbation theory .
it is found that the hard - scattering amplitude for the higher helicity components is of order @xmath2 , which is vanishingly small compared to that of the ordinary helicity component at very high @xmath3 but should be considered in the @xmath3 region where experimental data are available .
pacs number(s ) : 12.38.bx , 12.39.ki , 13.40.gp , 14.40.aq # 1#2#3#4#1 * # 2 * , # 3 ( # 4 ) the hard scattering amplitude for the higher helicity components of the pion form factor @xmath4 ccast ( world laboratory ) , p.o .
box 8730 , beijing 100080 , p. r. china @xmath5 institute of high energy physics , academia sinica , p.o .
box 918 , beijing 100039 , p. r. china @xmath6 institute of theoretical physics , academia sinica , p.o .
box 2735 , beijing 100080 , p. r. china |
strong gravitational lenses offer unique opportunities to study cosmology , dark matter , galactic structure , and galaxy evolution .
they also provide a sample of galaxies , namely the lenses themselves , that are selected based on total mass rather than luminosity or surface brightness .
the majority of lenses discovered in the past decade were found through dedicated surveys using a variety of techniques .
for example , the sloan digital sky survey ( sdss ) data have been used to effectively select lens candidates from rich clusters @xcite through intermediate scale clusters @xcite to individual galaxies @xcite .
other searches using the cfhtls @xcite and cosmos fields @xcite have yielded 40 and 70 lens candidates respectively .
these searches cover the range of giant arcs with einstein radii @xmath10 all the way to small arcs produced by single lens galaxies with @xmath11 .
in this paper we report on the serendipitous discovery of a strongly lensed @xmath12 galaxy in the blanco cosmology survey ( bcs ) imaging data .
the lens is a rich cluster containing a prominent central brightest cluster galaxy ( bcg ) and has a redshift of @xmath1 .
cluster - scale lenses are particularly useful as they allow us to study the effects of strong lensing in the core of the cluster and weak lensing in the outer regions .
strong lensing provides constraints on the mass contained within the einstein radius of the arcs whereas weak lensing provides information on the mass profiles in the outer reaches of the cluster . combining the two measurements allows us to make tighter constraints on the mass @xmath5 and the concentration @xmath7 , of an nfw @xcite model of the cluster mass density profile , over a wider range of radii than would be possible with either method alone @xcite .
in addition , if one has spectroscopic redshifts for the member galaxies one can determine the cluster velocity dispersion , assuming the cluster is virialized , and hence obtain an independent estimate for @xmath5 @xcite . finally one can also derive an @xmath5 estimate from the maxbcg cluster richness @xmath4 @xcite .
these three different methods , strong plus weak lensing , cluster velocity dispersion , and optical richness , provide independent estimates of @xmath5 ( @xmath5 is defined as the mass within a sphere of overdensity 200 times the critical density at the redshift @xmath3 ) and can then be combined to obtain improved constraints on @xmath5 and @xmath7 .
measurements of the concentration from strong lensing clusters is of particular interest as recent publications suggest that they may be more concentrated than one would expect from @xmath9cdm models @xcite .
the paper is organized as follows . in [ sec : bcs_survey ] we describe the blanco cosmology survey .
then in [
sec : discovery ] we discuss the initial discovery and the spectroscopic follow - up that led to confirmation of the system as a gravitational lens , the data reduction , the properties of the cluster , the extraction of the redshifts , and finally the measurement of the cluster velocity dispersion and estimate of the cluster mass . in
[ sec : lens_modeling ] we summarize the strong lensing features of the system . in
[ sec : weak_lens ] we describe the weak lensing measurements . in
[ sec : combined_constraints ] we present the results of combining of the strong and weak lensing results and the final mass constraints derived from combining the lensing results with the velocity dispersion and richness measurements .
we describe the source galaxy star formation rate measurements in [ sec : sfr ] and finally in [ sec : conclusions ] we conclude .
we assume a flat cosmology with @xmath13 , @xmath14 , and @xmath15 km s@xmath16 mpc@xmath16 , unless otherwise noted .
the blanco cosmology survey ( bcs ) is a 60-night noao imaging survey program ( 2005 - 2008 ) , using the mosaic - ii camera on the blanco 4 m telescope at ctio , that has uniformly imaged @xmath17 of the sky in the sdss @xmath18 bands in preparation for cluster finding with the south pole telescope ( spt ) @xcite and other millimeter - wave experiments .
the depths in each band were chosen to allow the estimation of photometric redshifts for @xmath19 galaxies out to a redshift of @xmath20 and to detect galaxies to @xmath21 at @xmath22 to these same redshifts .
the survey was divided into two fields to allow efficient use of the allotted nights between october and december .
both fields lie near @xmath23 which allows for overlap with the spt .
one field is centered near @xmath24 hr and the other is at @xmath25 hr .
in addition to the large science fields , bcs also covers 7 small fields that overlap large spectroscopic surveys so that photometric redshifts ( photo - z s ) using bcs data can be trained and tested using a sample of over 5,000 galaxies .
the lens bcs j2351 - 5452 was discovered serendipitously while examining @xmath2- and @xmath3-band images being acquired in october 2006 during the yearly bcs observing run .
the discoverer ( ejb - g ) decided to name it `` the elliot arc '' in honor of her then eight - year old nephew .
table [ table_obslog ] lists the observed images along with seeing conditions .
[ color_coadd ] shows a @xmath26 color image of the source , lens and surrounding environment ( the pixel scale is @xmath27 per pixel ) .
the source forms a purple ring - like structure of radius @xmath28 with multiple distinct bright regions .
the lens is the bcg at the center of a large galaxy cluster .
photometric measurements estimated the redshift of the cluster at @xmath29 , using the expected @xmath30 and @xmath31 red sequence colors , and also provided a photo - z for the source of @xmath32 , as described below . we note that this cluster was first reported as scso j235138@xmath33545253 in an independent analysis of the bcs data by @xcite where its remarkable lens was noted and they estimated a photometric redshift of @xmath34 for the cluster .
we obtained gemini multi - object spectrograph ( gmos ) spectra of the source and a number of the neighboring galaxies @xcite .
we targeted the regions of the source labeled a1-a4 in fig .
[ knot_targets ] , and photometric properties of these bright knots are summarized in table [ table_knots ] .
in addition we selected 51 more objects for a total of 55 spectra .
the additional objects were selected using their colors in order to pick out likely cluster member galaxies .
[ color - color ] shows the @xmath31 versus @xmath2 color - magnitude diagram ( top plot ) and the @xmath30 vs. @xmath31 color - color diagram ( bottom plot ) of the field .
the blue squares in the bottom panel of fig .
[ color - color ] show the four targeted knots in the lensed arcs .
the green curve is an scd galaxy model @xcite with the green circles indicating a photometric redshift for the arc of @xmath35 .
note this is not a detailed photo - z fit , but is just a rough estimate meant to show that the arc is likely at a redshift higher than the cluster redshift .
highest target priority was given to the arc knots and to the bcg .
then cluster red sequence galaxy targets were selected using the simple color cuts @xmath36 and @xmath37 ( also shown in the bottom panel of fig .
[ color - color ] ) , which approximate the more detailed final cluster membership criteria described below in [ sec : cluster_properties ] .
red sequence galaxies with @xmath38 ( @xmath39-diameter sextractor aperture magnitudes ) were selected , with higher priority given to brighter galaxies with @xmath40 .
additional non - cluster targets lying outside the cluster color selection box were added at lowest priority .
we used the gmos r150 grating + the gg455 filter in order obtain spectra with about 4600 9000 wavelength coverage .
this was designed to cover the [ oii ] 3727 emission line expected at @xmath41 , given the photo - z estimate of @xmath42 for the arcs as well as the mg absorption features at @xmath43 ( and the 4000 break at @xmath44 ) for the @xmath45 cluster elliptical galaxies .
we used 2 mos masks in order to fully target these cluster galaxies ( along with the arcs ) for spectroscopy .
each mask had a 3600 second exposure time split into 4 900-second exposures for cosmic ray removal .
we also took standard cu - ar lamp spectra for wavelength calibrations and standard star spectra for flux calibrations .
all data were taken in queue observing mode .
a summary of the observations is given in table [ table_obslog ] .
the bcs imaging data were processed using the dark energy survey data management system ( desdm v3 ) which is under development at uiuc / ncsa / fermilab @xcite .
the images are corrected for instrumental effects which include crosstalk correction , pupil ghost correction , overscan correction , trimming , bias subtraction , flat fielding and illumination correction .
the images are then astrometrically calibrated and remapped for later coaddition . for photometric data ,
a photometric calibration is applied to the single - epoch and coadd object photometry .
the astr@xmath46matic software sextractor @xcite , scamp @xcite and swarp @xcite are used for cataloging , astrometric refinement and remapping for coaddition over each image .
we have used the coadded images in the @xmath18 bands for this analysis .
the spectroscopic data were processed using the standard data reduction package provided by gemini that runs in the iraf framework .
we used version 1.9.1 .
this produced flux- and wavelength - calibrated 1-d spectra for all the objects .
additional processing for the source spectra was done using the iraf task apall .
we adopt the procedure used by the maxbcg cluster finder @xcite to determine cluster membership and cluster richness and to derive a richness - based cluster mass estimate .
we first measure @xmath47 , the number of cluster red sequence galaxies , within a radius @xmath48 mpc ( @xmath49 ) of the bcg , that are also brighter than @xmath50 at the cluster redshift @xmath51 . from @xcite
, @xmath50 corresponds to an @xmath2-band absolute magnitude @xmath52 at @xmath53 , while at @xmath51 , @xmath50 corresponds to an apparent magnitude @xmath54 ( specific value provided by j. annis & j. kubo , private communication ) , after accounting for both k - correction and evolution ( also as described in * ? ? ? * ) .
we apply this magnitude cut using the sextractor @xmath2-band mag_auto magnitude , which provides a measure of a galaxy s total light .
( note the @xmath39-diameter aperture magnitude used earlier for target selection in general measures less light cf .
mag_auto , but is better suited for roughly approximating the light entering a gmos slit . )
we set the red sequence membership cuts to be @xmath30 and @xmath31 color both within @xmath55 of their respective central values @xmath56 and @xmath57 , where the latter are determined empirically based on the peaks of the color histograms of galaxies within @xmath48 mpc of the bcg . in applying the color cuts we use the colors defined by sextractor @xmath39-diameter aperture magnitudes ( this provides higher s
/ n colors compared to using mag_auto ) , and for the uncertainty we define @xmath58 , where @xmath59 is the color measurement error derived from the sextractor aperture magnitude errors , and @xmath60 is the intrinsic red sequence color width , taken to be 0.05 for @xmath30 and 0.06 for @xmath31 @xcite . carrying out the above magnitude and color cuts , we obtain an initial richness estimate @xmath61 .
then , as discussed in @xcite , we define another radius @xmath62 ( @xmath63 ) , and repeat the same cuts within @xmath64 of the bcg to obtain a final richness estimate @xmath65 .
finally , using the weak lensing mass calibration of @xcite for maxbcg clusters , we obtain a mass estimate @xmath66 , where we have also adopted the fractional error of 0.45 derived by @xcite for this @xmath4-based estimate of @xmath5 for maxbcg clusters .
we note that @xcite apply a factor of 1.18 to correct the @xcite cluster masses upward , in order to account for a photo - z bias effect that is detailed in @xcite .
we have not applied this correction as it makes only a 0.4@xmath67 difference , although we remark that the resulting mass @xmath68 does appear to improve the ( already good ) agreement with our other mass estimates below ( see [ sec : veldisp ] and [ sec : combined ] ) .
[ color - color ] shows color - magnitude and color - color plots of all galaxies that have @xmath69 ( sextractor mag_auto ) and that are within a radius @xmath70 ( @xmath63 ) of the bcg .
note we have extended the magnitude limit here down to @xmath71 , to match the effective magnitude limit of our spectroscopic redshift sample ( [ sec : redshifts ] below ) in particular , we find 86 maxbcg cluster members for @xmath69 , compared to the earlier @xmath65 for @xmath72 ( corresponding to @xmath50 ) .
these member galaxies are shown using red symbols in fig .
[ color - color ] and their properties are given in table [ cluster_galaxies ] .
the redshift extraction was carried out using the xcsao and emsao routines in the iraf external package rvsao @xcite .
we obtained spectra for the 55 objects that were targeted .
four of these spectra were of the source .
out of the remaining 51 spectra we had sufficient signal - to - noise in 42 of them to determine a redshift .
thirty of the objects with redshifts between 0.377 and 0.393 constitute our spectroscopic sample of cluster galaxies .
[ all_targets ] shows the spatial distribution of galaxies within a @xmath73 box centered on the bcg , with maxbcg cluster members , arc knots , and objects with spectroscopic redshifts indicated by different colors and symbols .
table [ cluster_galaxies ] summarizes the properties of the 30 cluster member galaxies with redshifts , and table [ other_galaxies ] summarizes the properties of the remaining 12 spectroscopic non - member galaxies . in fig .
[ cluster_spectra ] we show four examples of the flux - calibrated cluster member spectra including the bcg .
examination of table [ cluster_galaxies ] and table [ other_galaxies ] shows that our spectroscopic sample is effectively limited at @xmath74 , as 39 of the 42 non - arc redshifts have @xmath69 .
note that of the 30 spectroscopically defined cluster members , 22 are also maxbcg members , while another 7 lie close to the maxbcg color selection boundaries . also , of the 12 spectroscopic non - members , none meets the maxbcg criteria except the faintest one ( with @xmath75 ) .
the redshift of the source was determined from a single emission line at 7100 which is present with varying signal - to - noise in each of the knots that were observed .
we take this line to be the [ oii]3727 line which yields a redshift of @xmath76 .
the four flux - calibrated source spectra are shown in fig .
[ arc_spectra ] .
knot a2 was observed under seeing conditions that were a factor of two worse than for the other three knots ( see table [ table_obslog ] ) .
we used the 30 cluster galaxies to estimate the redshift and velocity dispersion of the cluster using the biweight estimators of @xcite .
we first use the biweight location estimator to determine the best estimate for _ cz_. this yields a value of @xmath77 which translates to a redshift of @xmath78 .
we then use this estimate of the cluster redshift to determine the peculiar velocity @xmath79 for each cluster member relative to the cluster center of mass using @xmath80 we determine the biweight estimate of scale for @xmath79 which is equal to the velocity dispersion of the cluster .
we find a value for the velocity dispersion of @xmath81 .
the uncertainties are obtained by doing a jackknife resampling .
the redshift distribution is shown in fig .
[ vel_disp ] .
the overlaid gaussian has a mean of @xmath82 and a width of @xmath83 .
the lines represent the individual peculiar velocities @xmath79 of the cluster members .
we can use the estimated velocity dispersion to derive an estimate for the cluster mass .
we use the results of @xcite ( see also * ? ? ?
* ) which relates @xmath5 to the dark matter velocity dispersion @xmath84 where @xmath85 is the dimensionless hubble parameter .
the values of the parameters were found to be @xmath86 and @xmath87 @xcite . using the standard definition of velocity bias @xmath88 , where @xmath89 is the galaxy cluster velocity dispersion , we can rewrite equation [ eqn_m1 ] as @xmath90 where the quantity @xmath91 parameterizes our lack of knowledge about velocity bias . substituting in the measured values for @xmath89 we obtain @xmath92 .
* and references therein ) discuss an `` orientation bias '' effect which causes an upward bias in the measured velocity dispersions of lensing - selected clusters , due to the higher likelihood of the alignment along the line of sight of the major axes of the cluster halos , which are in general triaxial .
@xcite estimate that on average this will result in the dynamical mass estimate being biased high by 19 - 20% , using the same relation between @xmath5 and velocity dispersion as we have used ( eqn .
[ eqn_m1 ] above ; * ? ? ?
correcting for this orientation bias effect would result in @xmath93 , which is not a significant difference , as the change is well under @xmath94 .
we therefore do not apply this correction , but we do note that it would improve the already good agreement with our other mass estimates in [ sec : cluster_properties ] and [ sec : combined ] ( assuming no velocity bias , @xmath95 . )
we use the coadded @xmath96-band image shown in fig .
[ arc - r - band ] to study the strong lensing features of the system as it has the best seeing and hence shows the most detail . to remove the contribution to the arc fluxes from nearby objects we used galfit @xcite to model the profiles of these objects ( galaxies and stars ) and then subtracted the model from the image
this was done for all four bands @xmath18 .
these subtracted images are used for all determinations of arc fluxes and positions .
a number of individual knots can be observed in the system along with the more elongated features .
for example it appears that knot a1 is actually composed of two individual bright regions which are resolved by the sextractor object extraction described below .
knot a2 also appears to have two components although these are not resolved by the object extraction so we treat them as one in the modeling .
even though the cluster is fairly massive we do not see evidence for additional arc - like features outside of the central circular feature . in this case
we expect the mass of the lens to be well constrained by the image positions .
we use the criteria that to obtain multiple images the average surface mass density within the tangential critical curve must equal the critical surface mass density @xmath97 .
the tangentially oriented arcs occur at approximately the tangential critical curves and so the radius of the circle @xmath98 traced by the arcs provides a measurement of the einstein radius @xmath99 @xcite .
the mass @xmath100 enclosed with the einstein radius is therfore given by @xmath101 substituting for @xmath97 gives @xmath102 where @xmath103 is the angular diameter distance to the source , @xmath104 the angular diameter distance to the lens , and @xmath105 the angular diameter distance between the lens and the source .
these values are @xmath106 mpc , @xmath107 mpc and @xmath108 mpc . to determine the einstein radius we ran sextractor @xcite on the @xmath96-band image .
this identified eight distinct objects in the image .
we used the coordinates of those eight objects and fit them to a circle .
the radius of the circle gives us a measure of the einstein radius .
the einstein radius we measure is @xmath109 which translates to @xmath110 kpc .
this yields a mass estimate of @xmath111 and a corresponding velocity dispersion ( assuming an isothermal model for the mass distribution ) of @xmath112 .
the magnification of the lens @xmath113 can be roughly estimated under the assumption that the 1/2-light radius of a source at redshift @xmath114 is about @xmath115 ( derived from the mock galaxy catalog described in @xcite ) .
the ratio of the area subtended by the ring to that subtended by the source is @xmath116 , where @xmath117 is the ring radius and @xmath118 is the 1/2-light radius of the source .
the @xmath119 factor accounts for the fraction of the ring that actually contains images .
this gives a magnification of @xmath120 . to obtain a more quantitative value for the magnification we have used the pixelens program @xcite to model the lens .
pixelens is a parametric modeling program that reconstructs a pixelated mass map of the lens .
it uses as input the coordinates of the extracted image positions and their parities along with the lens and source redshifts .
it samples the solution space using a markov chain monte carlo method and generates an ensemble of mass models that reproduce the image positions .
we used the sextractor image positions obtained above and assigned the parities according to the prescription given in @xcite .
in @xcite they note that if one uses pixels that are too large then the mass distribution is poorly resolved and not enough steep mass models are allowed .
we have chosen a pixel size such that this should not be a problem .
it is well known ( see for example @xcite ) that changing the slope of the mass profile changes the overall magnification , in particular a steeper slope produces a smaller magnification but does not change the image positions . therefore the quoted magnification should be taken as a representative example rather than a definitive answer .
the magnification quoted is the sum over the average values of the magnification for each image position for 100 models .
we obtain a value of @xmath121 where the error is the quadrature sum of the rms spreads of the individual image magnifications .
pixelens can also determine the enclosed mass within a given radius .
for the 100 models we obtain @xmath122 which is within @xmath94 of the mass obtained from the circle fit described above . in order to combine the strong lensing mass with the mass estimate from the weak lensing analysis ( in [ sec : combined ] below ) we will need to estimate the mass within @xmath99 that is due to dark matter alone ( @xmath123 ) . to do this
we will need to subtract estimates of the stellar mass ( @xmath124 ) and the hot gas mass ( @xmath125 ) from the total mass @xmath100 . to determine @xmath124 we use the galaxev @xcite evolutionary stellar population synthesis code to fit galaxy spectral energy distribution models to the @xmath18 magnitudes of the bcg within the einstein radius .
the bcg photometric data are taken from the galfit modeling described above , and we sum up the light of the psf - deconvolved galfit model inside the einstein radius .
the galaxev models considered are simple stellar population ( ssp ) models which have an initial , instantaneous burst of star formation ; such models provide good fits to early - type galaxies , such as those in clusters .
in particular we find a good fit to the bcg , using a ssp model with solar metallicity , a @xcite stellar initial mass function ( imf ) , and an age 9.25 gyr ( this age provided the best @xmath126 over the range we considered , from 1 gyr to 9.3 gyr , the latter being the age of the universe for our cosmology at the cluster redshift @xmath51 ) .
the resulting stellar mass ( more precisely the total stellar mass integrated over the imf ) is @xmath127 . to estimate the gas mass @xmath125 we have looked at estimates of hot gas fraction @xmath128 in cluster cores from x - ray observations .
typical @xmath128 measurements are of order 10% @xcite which give us an @xmath125 estimate of @xmath129 .
finally we calculate the _ total _ @xmath130 ratio within @xmath99 for the @xmath2-band .
this yields a value of @xmath131 .
we used the program ellipto @xcite to compute adaptive moments @xcite of an object s light distribution , i.e. , moments optimized for signal - to - noise via weighting by an elliptical gaussian function self - consistently matched to the object s size .
ellipto computes adaptive moments using an iterative method and runs off of an existing object catalog produced by sextractor for the given image .
ellipto is also a forerunner of the adaptive moments measurement code used in the sdss photometric processing pipeline photo .
we ran ellipto on our coadded bcs images and corresponding sextractor catalogs , doing so independently in each of the @xmath18 filters to obtain four separate catalogs of adaptive second moments : @xmath132 where @xmath133 denotes the measured counts of an object at position @xmath134 on the ccd image , and @xmath135 is the elliptical gaussian weighting function determined by ellipto .
the images are oriented with the usual convention that north is up and east is to the left , i.e. , right ascension increases along the @xmath136 direction and declination increases along the @xmath137 direction .
we then computed the ellipticity components @xmath138 and @xmath139 of each object using one of the standard definitions @xmath140 for each filter , we then identified a set of bright but unsaturated stars to use for psf fitting .
we chose the stars from the stellar locus on a plot of the size measure @xmath141 from ellipto vs. the magnitude mag_auto from sextractor , using simple cuts on size and magnitude to define the set of psf stars .
we then derived fits of the ellipticities @xmath142 and the size @xmath141 of the stars vs. ccd @xmath143 and @xmath144 position , using polynomial functions of cubic order in @xmath143 and @xmath144 ( i.e. , the highest order terms are @xmath145 , and @xmath146 ) . on each image , these fits were done separately in each of 8 rectangular regions , defined by splitting the image area into 2 parts along the @xmath143 direction and into 4 parts along the @xmath144 direction , corresponding to the distribution of the 8 mosaic - ii ccds over the image .
this partitioning procedure was needed in order to account for discontinuities in the psf ellipticity and/or size as we cross ccd boundaries in the mosaic - ii camera .
also note that the individual exposures comprising the final coadded image in each filter were only slightly dithered , so that the ccd boundaries were basically preserved in the coadd . to illustrate the psf variation in our images , we present in figure [ fig_psf_whiskers ] `` whisker plots '' that show the spatial variation of the magnitude and orientation of the psf ellipticity across our @xmath2- and @xmath96-band images .
in addition , we also show the residuals in the psf whiskers remaining after our fitting procedure , showing that the fits have done a good job of modeling the spatial variations of the psf in our data .
we next used our psf model to correct our galaxy sizes and ellipticities for the effects of psf convolution . specifically , for the size measure @xmath141 we used the simple relation ( cf . * ? ? ? * ) @xmath147 to estimate the true size @xmath148 of a galaxy from its observed size @xmath149 , where @xmath150 is obtained from the psf model evaluated at the @xmath134 position of the galaxy . for the ellipticities we similarly used the related expressions @xmath151 the relations used in this simple correction procedure strictly hold only for unweighted second moments , or for adaptive moments in the special case when both the galaxy and the psf are gaussians .
we have therefore also checked the results using the more sophisticated `` linear psf correction '' procedure of @xcite , which uses additional fourth order adaptive moment measurements ( also provided here by ellipto ) in the psf correction procedure .
in particular , the linear psf correction method is typically applied in weak lensing analyses of sdss data .
however , we found nearly indistinguishable tangential shear profiles from applying the two psf correction methods , and we therefore adopted the simpler correction method for our final results . given the estimates of the true galaxy ellipticities from equation ( [ eqn_etrue ] ) , we then computed the tangential ( @xmath152 ) and b - mode or cross ( @xmath153 ) ellipticity components , in a local reference frame defined for each galaxy relative to the bcg : @xmath154 where @xmath155 is the position angle ( defined west of north ) of a vector connecting the bcg to the galaxy in question . here
we have dropped the subscript _ true _ for brevity .
the ellipticities were then converted to shears @xmath156 using @xmath157 , where @xmath117 is the responsivity , for which we adopted the value @xmath158 , using @xmath159 as the intrinsic galaxy shape noise as done in previous sdss cluster weak lensing analyses ( e.g. , * ? ? ?
* ; * ? ? ?
we then fit our galaxy shear measurements to an nfw profile by minimizing the following expression for @xmath126 : @xmath160 ^ 2 } { \sigma_\gamma^2 } \label{eqn_chi2}\ ] ] where the index @xmath2 refers to each of the @xmath161 galaxies in a given sample , @xmath162 is a galaxy s projected physical radius from the bcg ( at the redshift of the cluster ) , @xmath163 is the measured standard deviation of the galaxy shears , and @xmath164 is the shear given by equations ( 14 - 16 ) of @xcite for an nfw profile with mass @xmath5 and concentration @xmath7 .
we used a standard levenberg - marquardt nonlinear least - squares routine to minimize @xmath126 and obtain best - fitting values and errors for the parameters @xmath5 and @xmath7 of the nfw profile .
similar fits of the weak lensing radial shear profile to a parameterized nfw model have often been used to constrain the mass distributions of galaxy clusters ( e.g. , * ? ? ?
* ; * ? ? ?
? * ; * ? ? ?
* ; * ? ? ?
note that we chose the above expression for @xmath126 since it does _ not _ require us to do any binning in radius , but for presentation purposes below we will have to show binned radial shear profiles compared to the nfw shear profiles obtained from our binning - independent fitting method . for the shear fitting analysis , we defined galaxy samples separately in each of the four @xmath18 filters using cuts on the magnitude mag_auto and on the size @xmath149 , as detailed in table [ table_weak_lensing ] .
the bright magnitude cut was chosen to exclude brighter galaxies which would tend to lie in the foreground of the cluster and hence not be lensed , while the faint magnitude cuts were set to the photometric completeness limit in each filter , as defined by the turnover magnitude in the histogram of sextractor mag_auto values . for the size cut
, we set it so that only galaxies larger than about 1.5 times the psf size would be used , as has been typically done in sdss cluster weak lensing analyses ( e.g. , * ? ? ?
* ; * ? ? ?
note that in order to properly normalize the nfw shear profile to the measurements , we also need to calculate the critical surface mass density @xmath97 , which depends on the redshifts of the lensed source galaxies as well as the redshift of the lensing cluster ; see equations ( 9,14 ) of @xcite . to do this , we did not use any individual redshift estimates for the source galaxies in our analysis , but instead we calculated an effective value of @xmath165 via an integral over the source galaxy redshift distribution published for the canada - france - hawaii telescope legacy survey ( cfhtls ; * ? ? ?
* ) , as appropriate to the magnitude cuts we applied in each of the @xmath18 filters .
our nfw fitting results are shown in figures [ nfw_fit_ir]-[nfw_fit_zg ] and detailed in table [ table_weak_lensing ] .
we show results for both the tangential and b - mode shear components .
as lensing does not produce a b - mode shear signal , these results provide a check on systematic errors and should be consistent with zero in the absence of significant systematics . for all of our filters ,
our b - mode shear results are indeed consistent with no detected mass , as the best - fit @xmath5 is within about 1@xmath67 of zero . on the other hand , for the tangential shear results in the @xmath96 , @xmath2 , and @xmath3 filters , we do indeed obtain detections of non - zero @xmath5 at the better than @xmath166 level . in the @xmath167 filter
we do not detect a non - zero @xmath5 . comparing the weak lensing results from the different filters serves as a useful check of the robustness of our lensing - based cluster mass measurement , in particular as the images in the different filters are subject to quite different psf patterns , as shown earlier in fig .
[ fig_psf_whiskers ] .
though the mass errors are large , the @xmath5 values from the @xmath96- , @xmath2- , and @xmath3-band weak lensing nfw fits are nonetheless consistent with each other and with the masses derived earlier from the velocity dispersion and maxbcg richness analyses .
moreover , independent of the nfw fits , we have also derived probabilities ( of exceeding the observed @xmath126 ) that our _ binned _ shear profiles are consistent with the null hypothesis of zero shear . as shown in table [ table_weak_lensing ] , we see that the b - mode profiles are in all cases consistent with zero , as expected , but that the tangential profiles for the @xmath96 and @xmath2 filters are not consistent with the null hypothesis at about the @xmath55 level ( probabilities @xmath168 ) , thus providing model - independent evidence for a weak lensing detection of the cluster mass . here
we will combine the weak lensing shear profile information from the different filters @xmath18 in order to improve the constraints on the nfw parameters , in particular on @xmath5 .
the main complication here is that although the ellipticity measurement errors are independent among the different filters , the most important error for the shear measurement is the intrinsic galaxy shape noise , which is correlated among filters because a subset of the galaxies is common to two or more filters , and for these galaxies we expect their shapes to be fairly similar in the different filters .
in particular we find that the covariance of the true galaxy ellipticities between filters is large , for example , the covariance of @xmath138 between the @xmath2 and @xmath96 filters , @xmath169 , is about 0.9 times the variance of @xmath138 in the @xmath2 and @xmath96 filters individually .
the same holds true for @xmath139 and for the other filters as well .
we will not attempt to use a full covariance matrix approach to deal with the galaxy shape correlations when we combine the data from two or more filters .
instead , we take a simpler approach of scaling the measured standard deviation of the shear ( the @xmath163 used to calculate @xmath126 in equation [ eqn_chi2 ] ) by @xmath170 , where @xmath161 is the total number of galaxies in a given multi - filter sample , and @xmath171 is the number of unique galaxies in the same sample .
this is equivalent to rescaling @xmath126 in the nfw fit to correspond to @xmath171 degrees of freedom instead of @xmath161 .
we have verified using least - squares fits to monte carlo simulations of nfw shear profiles that this simple approach gives the correct fit uncertainties on @xmath5 and @xmath7 when the mock galaxy data contain duplicate galaxies , with identical @xmath138 and @xmath139 values , simulating the case of _ completely _ correlated intrinsic galaxy shapes among filters .
note that our approach is conservative and will slightly overestimate the errors , because the galaxy shapes in the real data are about 90% correlated , not fully correlated , among filters . before fitting the combined shear data from multiple filters ,
we make one additional multiplicative rescaling of the shear values , so that all filters will have the same effective value of @xmath165 , corresponding to a fiducial effective source redshift @xmath172 .
this correction is small , with the largest being a factor of 1.18 for the @xmath3-band data .
the results of the nfw fits for the multi - filter samples are given in table [ table_weak_lensing ] , where we have tried the filter combinations @xmath173 , @xmath174 , and @xmath175 .
we see that these multi - filter samples all provide better fractional errors on @xmath5 compared to those from the single - filter data . also , as expected , the b - mode results in all cases are consistent with no detected @xmath5 and zero shear . for our final weak lensing results ,
we adopt the nfw parameters from the @xmath174 sample , as it provides the best fractional error ( @xmath176 ) on @xmath5 ; we obtain @xmath177 , and @xmath178 .
figure [ nfw_fit_irz_sl ] shows the shear profile data and best fit results for the @xmath174 sample .
this final weak lensing value for @xmath5 agrees well with the earlier values of @xmath5 derived from the cluster galaxy velocity dispersion ( assuming no velocity bias ) and from the cluster richness @xmath4 .
in this section we combine the strong lensing and weak lensing information together in order to further improve our constraints on the nfw profile parameters , in particular on the concentration parameter @xmath7 .
the addition of the strong lensing information provides constraints on the mass within the einstein radius , close to the cluster center , thereby allowing us to better measure the central concentration of the nfw profile and improve the uncertainties on the concentration @xmath7 .
@xcite incorporated the strong lensing information in the form of a constraint on the einstein radius due to just the dark matter distribution of the cluster , and they specifically excluded the contribution of ( stellar ) baryons to the einstein radius . their intent , as well as ours in this paper ( [ sec : all_combined ] ) , is to compare the observed cluster nfw concentration to that predicted from dark - matter-_only _ simulations .
thus the contribution of baryonic matter should be removed , most importantly in the central region within the einstein radius , where baryonic effects are the largest due in particular to the presence of the bcg . in practice with the present data we can do this separation of the baryonic contribution only for the strong lensing constraint , and strictly speaking the weak lensing profile results from the total mass distribution rather than from dark matter alone . here
we combine the strong and weak lensing data using an analogous but somewhat simpler method compared to that of @xcite , specifically by adding a second term to @xmath126 ( equation [ eqn_chi2 ] ) that describes the constraint on the dark matter ( only ) mass within the observed einstein radius : @xmath160 ^ 2 } { \sigma_\gamma^2 } + \frac{[m_{dm } ( < \theta_e ) - m_{nfw } ( < \theta_e ; m_{200},c_{200})]^2 } { \sigma_{m_{dm } ( < \theta_e)}^2 } \label{eqn_chi2_wl_sl}\ ] ] where @xmath179 is the observed einstein radius due to the _ total _ cluster mass distribution , @xmath180 is the dark matter ( only ) mass within @xmath181 , and @xmath182 is the mass within @xmath181 of an nfw profile with mass @xmath5 , concentration @xmath7 , redshift @xmath51 , and source redshift @xmath0 .
@xmath182 is derived based on equation ( 13 ) of @xcite . as obtained earlier in [ sec : lens_modeling ] , we estimate @xmath180 by subtracting estimates of the stellar mass and hot gas mass from the total mass within @xmath181 , obtaining @xmath183 when subtracting off both stellar and gas mass , or @xmath184 when subtracting off only stellar mass .
the former is our best estimate of @xmath180 , while the latter serves as an upper limit on @xmath180 and hence on the best - fit concentration @xmath7 .
we also conservatively estimate the error on @xmath180 to be one of the stellar mass / gas mass components added in quadrature to the uncertainty on the total @xmath100 from [ sec : lens_modeling ] .
we apply the combined strong plus weak lensing analysis to our best weak lensing sample , the multi - filter @xmath174 data set .
the fit results are given in table [ table_weak_lensing ] and shown in figure [ nfw_fit_irz_sl ] .
we find @xmath185 solar masses , nearly identical to the final weak lensing result .
we also get a concentration @xmath186 , again consistent with the final weak lensing fit , but with a 30% improvement in the error on @xmath7 , demonstrating the usefulness of adding the strong lensing information to constrain the nfw concentration . using the upper limit @xmath180 value ( with only stellar mass subtracted ) gives nearly the same @xmath187 , while the resulting nfw concentration is higher , as expected , with @xmath188 , but still consistent with the fit using our best estimate of @xmath180 . in the above sections we have obtained quite consistent constraints on the cluster mass @xmath5 using three independent techniques : ( 1 ) @xmath189 from combined weak + strong lensing ( [ sec : combined ] ) ; ( 2 ) @xmath190 from the cluster galaxy velocity dispersion @xmath191 ( [ sec : veldisp ] ; assuming no velocity bias , @xmath95 ) ; and ( 3 ) @xmath192 from the maxbcg - defined cluster richness @xmath4 ( [ sec : cluster_properties ] ) .
we note that these methods are subject to different assumptions and systematic errors .
for example , the velocity dispersion based mass estimate assumes the cluster is virialized , an assumption supported by the gaussian - shaped velocity distribution of the cluster members shown in fig .
[ vel_disp ] . also , the richness based mass estimate relies on the @xmath4-@xmath5 calibration @xcite obtained for sdss maxbcg clusters at lower redshifts @xmath193 and assumes that this calibration remains valid for our cluster at @xmath51 .
it is encouraging that we are obtaining a cluster mass measurement that appears to be robust to these disparate assumptions and that shows good agreement among multiple independent methods .
we will therefore combine the results from the different techniques in order to obtain final constraints on @xmath5 and concentration @xmath7 that are significantly improved over what any one technique permits .
specifically , we can add the @xmath5 constraints from the velocity dispersion and richness measurements as additional terms to the weak + strong lensing @xmath126 ( equation [ eqn_chi2_wl_sl ] ) : @xmath194 ^ 2 } { \sigma_\gamma^2 } + \frac{[m_{dm } ( < \theta_e ) - m_{nfw } ( < \theta_e ; m_{200},c_{200})]^2 } { \sigma_{m_{dm } ( < \theta_e)}^2 } \nonumber \\ & + & \frac{[m_{200}(\sigma_c)-m_{200}]^2}{\sigma_{m_{200}(\sigma_c)}^2 } + \frac{[m_{200}(n_{200})-m_{200}]^2}{\sigma_{m_{200}(n_{200})}^2 } \label{eqn_chi2_all}\end{aligned}\ ] ] minimizing this overall @xmath126 results in the final best - fitting nfw parameters @xmath195 and @xmath8 .
these results are consistent with the final lensing - based values @xmath189 and @xmath196 , but have errors nearly a factor of two smaller .
note these quoted errors are 1-parameter , @xmath94 uncertainties ; we plot the joint 2-parameter , @xmath94 and @xmath55 contours in fig .
[ contours_m200_c ] .
we also note that for the three methods weak lensing , velocity dispersion , and cluster richness , the corresponding nfw parameters result from the _ total _ mass distribution , consisting of both dark matter and baryonic ( stellar plus hot gas ) components .
dark matter is dominant over the bulk of the cluster , while baryons can have a significant effect in the cluster core ( e.g. , * ? ? ?
as described earlier ( [ sec : combined ] ) , we have thus subtracted off the baryonic contribution to the strong lensing constraint as the intent is to compare ( see below ) our cluster concentration value against those from dark - matter - only simulations . note that we have not isolated the dark matter contribution for the other three methods and can not easily do so . for weak lensing ,
the shear profile is sensitive to the total mass distribution , not just to dark matter . for the velocity dispersion method ,
the galaxies act as test particles in the overall cluster potential , which is due , again , to both dark matter and baryons . for the cluster richness method ,
the @xcite @xmath4-@xmath5 relation we use was derived from stacked cluster weak lensing shear profile fits , including a bcg contribution but otherwise no other baryonic components ; thus again the @xmath5 value is essentially for the total mass distribution .
nonetheless , the bulk of the baryonic contribution is in the cluster core and is accounted for via the strong lensing constraint , so we expect the comparison below of our cluster concentration value to those of dark matter simulations to be a reasonable exercise .
recent analyses ( e.g. , * ? ? ?
* ; * ? ? ?
* ) of strong lensing clusters have indicated that these clusters are more concentrated than would be expected from @xmath9cdm predictions , though others have argued that no discrepancy exists if baryonic effects are accounted for @xcite . in the former case
, @xcite found a concentration @xmath197 for the 10 strong lensing clusters in their analysis sample , compared to a value of @xmath198 expected for strong - lensing - selected clusters or @xmath199 for clusters overall ( e.g. , * ? ? ?
we illustrate these different concentration values in fig .
[ contours_m200_c ] .
we use eqn .
( 17 ) of @xcite , @xmath200 , which comes from the @xmath9cdm n - body simulations of @xcite , to show the typical concentration of clusters overall , and multiply by a factor of 1.5 @xcite to show the higher concentration expected for lensing selected clusters .
we also use eqn . ( 18 ) of @xcite , @xmath201 , to show the fit results for their cluster sample . in these relations
, we set @xmath202 to match the redshift of our cluster .
moreover , we convert from the @xmath203 convention used by @xcite to our @xmath204 convention , using the detailed relations found in appendix c of @xcite or in the appendix of @xcite . for the plotted @xmath5 range , it turns out that @xmath205 . from fig .
[ contours_m200_c ] , we see that our best - fit value of @xmath8 is most consistent with the nominal @xmath9cdm concentration value for lensing - selected clusters , and does not suggest the need for a concentration excess in this particular case .
it s likely that larger strong lensing cluster samples will be needed to more robustly compare the distribution of concentration values with the predictions of @xmath9cdm models .
we can use the [ oii]3727 line in the calibrated spectra described in [ sec : redshifts ] to estimate the star formation rate ( sfr ) . as noted by @xcite the luminosities of forbidden lines like [ oii]3727
are not directly coupled to the ionizing luminosity and their excitation is also sensitive to abundance and the ionization state of the gas .
however the excitation of [ oii ] is well behaved enough that it can be calibrated through h@xmath206 as an sfr tracer .
this indirect calibration is very useful for studies of distant galaxies because [ oii]3727 can be observed out to redshifts @xmath207 and it has been measured in several large samples of faint galaxies ( see references in @xcite ) .
if we know the [ oii ] luminosity then we can use equation 3 from @xcite to determine a star formation rate for the galaxy @xmath208})({\rm ergs\ s}^{-1})\label{eqn_sfr}\ ] ] where the uncertainty reflects the range between blue emission - line galaxies ( lower limit ) and more luminous spiral and irregular galaxies ( upper limit ) . as noted above , in order to extract the sfr we need to determine the total source flux from the [ oii ] line .
we determine this using @xmath209 } = \frac{f(\nu)_l}{f(\nu)_s}\times f(\nu)_i \label{eqn_sfr_flux}\ ] ] where @xmath210}$ ] is the total flux emitted by the source in the [ oii ] line , @xmath211 is the flux measured in the [ oii ] line in each spectrum , @xmath212 is the flux in the knot spectrum contained within the _ i_-band filter band pass and @xmath213 is the flux from the source in the _ i_-band . using the galfit - subtracted _ i_-band image we determine @xmath213 by summing the flux in an annulus of width 3 that encompasses the arcs . the flux @xmath211 is measured by fitting a gaussian plus a continuum to the [ oii ] line in each spectrum and integrating the flux under the gaussian fit .
the flux @xmath212 is calculated as follows . for each spectrum
we first fit the continuum level , we then add the fitted continuum plus the [ oii ] line flux and convolve it with the filter response curve for the sdss _
i_-band filter and integrate the convolved spectrum .
we have determined @xmath210}$ ] separately for each knot that was targeted for spectra .
the fluxes are listed in table [ table_sfr ] for each knot .
we convert @xmath210}$ ] into an [ oii ] luminosity and then use equation [ eqn_sfr ] to determine a star formation rate for each knot .
this rate is the raw rate which must be scaled by the lens magnification @xmath113 to determine the true rate .
we quote the sfr for the two values of @xmath113 that were determined in [ sec : lens_modeling ] .
we assume one magnitude of extinction @xcite and have corrected the measured [ oii ] luminosity to account for this .
this yields the star formation rates listed in table [ table_sfr ] for the two values of @xmath113 .
the rate for knot a3 is higher by a factor of 2 compared to the others because it has a small @xmath212 compared to the other knots but the value of @xmath211 is quite similar to the other knots .
this can clearly be seen in figure [ arc_spectra ] .
we can combine the measurements for the four knots using a simple average to quote an overall sfr .
this yields values of @xmath214 and @xmath215 .
these rates are significantly smaller that those obtained for the 8 oclock arc @xcite and the clone @xcite which were @xmath216 and @xmath217 respectively ( after converting to our chosen cosmology ) .
both these systems were at much higher redshift ( 2.72 and 2.0 respectively ) so one would potentially expect higher rates from these systems .
they also had smaller values of @xmath113 .
we can compare our result to blue galaxies at similar redshift from the deep2 survey @xcite .
using figure 18 of @xcite we obtain a median sfr of about @xmath218 for a redshift @xmath219 galaxy which is also higher than our measurement .
other measurements using the aegis field @xcite give a median sfr ranging from @xmath220 to @xmath221 depending weakly on the galaxy mass , which is unknown in our case .
our measurement can be compared to the far - right plot of figure 1 in @xcite and we fall on the low side of the measured data . note that these conclusions are dependent on the magnification values used , for example smaller values such as those obtained for the clone or the 8 oclock arc would yield larger values for the sfr .
we have reported on the discovery of a star - forming galaxy at a redshift of @xmath12 that is being strongly lensed by a massive galaxy cluster at a redshift of @xmath1 .
we have derived estimates of @xmath5 from measurements of ( 1 ) weak lensing , ( 2 ) weak + strong lensing , ( 3 ) velocity dispersion @xmath191 , and ( 4 ) cluster richness @xmath65 .
we obtained the following results for @xmath5 : ( 1 ) @xmath223 , ( 2 ) @xmath189 , ( 3 ) @xmath190 ( assuming no velocity bias , @xmath95 ) , and ( 4 ) @xmath192 .
these results are all very consistent with each other .
the combination of the results from methods 2 , 3 and 4 give @xmath224 , which is fully consistent with the individual measurements but with an error that is smaller by a factor of nearly two . the final nfw concentration from the combined fit
is @xmath8 , which is also consistent with the lensing - based value but again with a smaller error .
we have compared our measurements of @xmath5 and @xmath7 with predictions for ( a ) clusters from @xmath9cdm simulations , ( b ) lensing selected clusters from simulations , and ( c ) a real sample of cluster lenses from @xcite .
we find that we are most compatible with the predictions from @xmath9cdm simulations for lensing clusters , and we see no evidence that an increased concentration is needed for this one system .
we are studying this further using other lensing clusters we observed from the sdss @xcite .
these clusters will be the subject of a future paper .
finally , we have estimated the star forming rate ( sfr ) to be between 1.3 to 4.6 @xmath225 , depending on magnification .
these are small star - forming rates when compared to some of our previously reported systems , and are also small when compared with rates found for other galaxies at similar redshifts .
however we caution that this conclusion is entirely dependent on the derived lens magnification . based on observations obtained at the gemini observatory , which is operated by the association of universities for research in astronomy , inc .
, under a cooperative agreement with the nsf on behalf of the gemini partnership : the national science foundation ( united states ) , the science and technology facilities council ( united kingdom ) , the national research council ( canada ) , conicyt ( chile ) , the australian research council ( australia ) , ministrio da cincia e tecnologia ( brazil ) and ministerio de ciencia , tecnologa e innovacin productiva ( argentina ) .
gemini proposal i d gs-2007b - q-228 .
the blanco cosmology survey was performed on the blanco 4 m telescope located at the cerro tololo inter - american observatory ( national optical astronomy observatory ) which is operated by the association of universities for research in astronomy , under contract with the national science foundation .
s. s. allam acknowledges support from an hst grant .
support of program no .
11167 was provided by nasa through a grant from the space telescope science institute , which is operated by the association of universities for research in astronomy , inc .
, under nasa contract nas5 - 26555 .
thanks to jeff kubo for providing a copy of the ellipto adaptive moments code .
thanks also go to quarknet students liana nicklaus , gina castelvecchi , braven leung , nick gebbia , alex fitch , and their advisor patrick swanson , who worked with hl during summer 2009 on a weak lensing mass analysis of this cluster with different codes than used here .
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. , & brainerd , t.g . 1999 , , 534 , 34 zenteno , a. , et al . , 2011 , 734 , 3 vs. @xmath2(mag_auto ) color - magnitude diagram for all galaxies ( black points ) with @xmath69 and within a radius @xmath70 ( @xmath63 ) of the bcg
colors are measured using @xmath39-diameter aperture magnitudes .
galaxies meeting the maxbcg cluster color selection criteria ( see [ sec : cluster_properties ] ) are plotted in red , with red circles indicating cluster members brighter than @xmath54 , and red squares indicating fainter cluster members .
( bottom ) @xmath30 vs. @xmath31 color - color diagram for the same galaxies as in the top panel .
red circles and squares again indicate brighter and fainter maxbcg cluster members , while the black rectangle indicates the color selection box ( approximating the more detailed maxbcg color criteria ) used to select likely cluster galaxies for gmos spectroscopy ( see [ sec : discovery ] ) .
in addition , the 4 bright knots a1-a4 ( fig . [ knot_targets ] ) in the lensed arcs are shown by the blue squares .
the green curve is an scd galaxy model @xcite at redshifts @xmath226 , with green circles highlighting the redshift range @xmath227 , indicating an approximate photometric redshift @xmath35 for the arc knots .
[ color - color ] ] ccccl @xmath167 & 14 dec 2006 & 2@xmath228 sec & @xmath229 & + @xmath96 & 14 dec 2006 & 2@xmath230 sec & @xmath231 & + @xmath167 & 11 nov 2008 & 2@xmath228 sec & @xmath232 & + @xmath96 & 11 nov 2008 & 2@xmath230 sec & @xmath233 & + @xmath2 & 30 oct 2006 & 3@xmath234 sec & @xmath235 & + @xmath3 & 30 oct 2006 & 3@xmath234 sec & @xmath236 & + gg455 & 4 aug 2007 & 4@xmath237 sec & @xmath238 & mask 1 includes knots
a1,a3,a4 + gg455 & 4 aug 2007 & 4@xmath237 sec & @xmath239 & mask 2 includes bcg and knot a2 + gg455 & 4 aug 2007 & 1@xmath240 sec & - & cu - ar mask 1 + gg455 & 4 aug 2007 & 1@xmath240 sec & - & cu - ar mask 2 + gg455 & 14 aug 2007 & 1@xmath240 sec & - & @xmath241 slit + gg455 & 14 aug 2007 & 1@xmath242sec & @xmath243 & standard star eg21 + cccccc a1 & 357.912477 & -54.881691 & 21.94 & 0.85 & 0.77 + a2 & 357.911467 & -54.882801 & 21.49 & 0.81 & 0.69 + a3 & 357.906225 & -54.883464 & 22.30 & 0.84 & 0.74 + a4 & 357.907100 & -54.879967 & 21.46 & 0.91 & 0.77
+ ccccccc 15173 ( bcg ) & 357.908555 & -54.881611 & @xmath244 & @xmath245 & @xmath246 & @xmath247 + 16097 & 357.972190 & -54.856522 & @xmath248 & @xmath249 & @xmath250 & + 16926 & 358.069064 & -54.838013 & @xmath251 & @xmath252 & @xmath253 & + 14954 & 357.990606 & -54.881805 & @xmath254 & @xmath255 & @xmath256 & + 14458 & 357.922935 & -54.891348 & @xmath257 & @xmath258 & @xmath259 & @xmath260 + 15111 & 357.911305 & -54.879770 & @xmath261 & @xmath262 & @xmath263 & + 13772 & 357.854114 & -54.908062 & @xmath264 & @xmath265 & @xmath266 & + 14873 & 357.913389 & -54.883120 & @xmath267 & @xmath255 & @xmath259 & + 15204 & 357.917968 & -54.874795 & @xmath267 & @xmath268 & @xmath263 & @xmath269 + 15305 & 357.929749 & -54.874524 & @xmath270 & @xmath271 & @xmath259 & + 15124 & 357.915316 & -54.877257 & @xmath272 & @xmath273 & @xmath266 & @xmath274 + 11813 & 357.856326 & -54.957697 & @xmath275 & @xmath276 & @xmath277 & + 13629 & 357.781583 & -54.911494 & @xmath278 & @xmath279 & @xmath263 & + 16084 & 357.932492 & -54.855191 & @xmath280 & @xmath281 & @xmath282 & @xmath283 + 14828 & 357.858498 & -54.884039 & @xmath284 & @xmath262 & @xmath282 & + 15056 & 357.929263 & -54.878393 & @xmath284 & @xmath285 & @xmath250 & + 13028 & 357.836914 & -54.923702 & @xmath284 & @xmath276 & @xmath266 & + 14267 & 357.742239 & -54.897565 & @xmath286 & @xmath287 & @xmath288 & + 13939 & 357.743518 & -54.903441 & @xmath289 & @xmath290 & @xmath291 & + 14892 & 357.917045 & -54.881040 & @xmath292 & @xmath279 & @xmath293 & + 17276 & 358.061857 & -54.827190 & @xmath294 & @xmath295 & @xmath282 & + 12997 & 357.992988 & -54.925261 & @xmath296 & @xmath297 & @xmath291 & + 14685 & 357.948912 & -54.885316 & @xmath296 & @xmath298 & @xmath291 & + 14727 & 357.914364 & -54.884540 & @xmath299 & @xmath300 & @xmath263 & + 12907 & 357.971817 & -54.926860 & @xmath301 & @xmath302 & @xmath250 & + 15525 & 357.891439 & -54.867148 & @xmath303 & @xmath304 & @xmath282 & @xmath305 + 13874 & 357.767222 & -54.904760 & @xmath306 & @xmath307 & @xmath308 & + 14875 & 357.896375 & -54.880676 & @xmath309 & @xmath310 & @xmath282 & + 14827 & 357.956282 & -54.883059 & @xmath311 & @xmath312 & @xmath256 & + 14169 & 357.942454 & -54.896963 & @xmath313 & @xmath314 & @xmath282 & + 14620 & 357.906482 & -54.885446 & @xmath315 & @xmath316 & @xmath259 & @xmath317 + 11254 & 357.792343 & -54.968633 & @xmath318 & @xmath262 & @xmath277 & + 19279 & 357.988291 & -54.784591 & @xmath319 & @xmath320 & @xmath282 & + 15027 & 357.880749 & -54.878200 & @xmath321 & @xmath307 & @xmath277 & @xmath322 + 12805 & 357.947638 & -54.929596 & @xmath323 & @xmath324 & @xmath325 & + 13899 & 358.003818 & -54.902294 & @xmath326 & @xmath327 & @xmath259 & + 14741 & 357.943783 & -54.884299 & @xmath328 & @xmath329 & @xmath256 & + 12671 & 358.055413 & -54.931583 & @xmath330 & @xmath331 & @xmath332 & + 14843 & 357.901141 & -54.880772 & @xmath333 & @xmath334 & @xmath335 & + 14088 & 357.936003 & -54.898050 & @xmath336 & @xmath337 & @xmath256 & @xmath338 + 14969 & 357.910388 & -54.878452 & @xmath339 & @xmath340 & @xmath263 & + 12875 & 357.935888 & -54.927451 & @xmath341 & @xmath342 & @xmath263 & + 13537 & 357.937414 & -54.911304 & @xmath343 & @xmath344 & @xmath308 & @xmath345 + 15314 & 357.902668 & -54.872019 & @xmath346 & @xmath347 & @xmath348 & @xmath349 + 14669 & 357.916522 & -54.885626 & @xmath350 & @xmath351 & @xmath352 & @xmath353 + 14639 & 357.954384 & -54.885672 & @xmath350 & @xmath354 & @xmath282 & + 14232 & 357.904683 & -54.895183 & @xmath355 & @xmath307 & @xmath263 & @xmath356 + 14703 & 357.865075 & -54.884639 & @xmath357 & @xmath358 & @xmath359 & + 14690 & 357.914016 & -54.883857 & @xmath360 & @xmath361 & @xmath263 & + 15463 & 357.882797 & -54.868348 & @xmath362 & @xmath363 & @xmath277 & @xmath364 + 16005 & 357.991736 & -54.856356 & @xmath365 & @xmath347 & @xmath259 & + 15333 & 357.975175 & -54.872090 & @xmath365 & @xmath366 & @xmath277 & + 14972 & 357.909534 & -54.878210 & @xmath367 & @xmath368 & @xmath369 & + 14086 & 357.829155 & -54.897455 & @xmath370 & @xmath361 & @xmath332 & + 18418 & 357.768333 & -54.801860 & @xmath371 & @xmath372 & @xmath332 & + 13764 & 357.905657 & -54.906287 & @xmath373 & @xmath374 & @xmath266 & + 10692 & 357.819108 & -54.981725 & @xmath375 & @xmath376 & @xmath377 & + 15516 & 357.931958 & -54.867137 & @xmath378 & @xmath379 & @xmath335 & @xmath380 + 19588 & 357.961069 & -54.776725 & @xmath381 & @xmath382 & @xmath377 & + 15002 & 357.897311 & -54.877856 & @xmath383 & @xmath347 & @xmath384 & @xmath385 + 14800 & 357.901708 & -54.880859 & @xmath386 & @xmath374 & @xmath263 & + 15788 & 357.914426 & -54.860804 & @xmath387 & @xmath388 & @xmath377 & @xmath389 + 15373 & 357.965957 & -54.874282 & @xmath387 & @xmath390 & @xmath377 & @xmath391 + 13697 & 357.905543 & -54.907479 & @xmath392 & @xmath393 & @xmath369 & @xmath394 + 15187 & 357.874035 & -54.873868 & @xmath395 & @xmath351 & @xmath377 & @xmath396 + 18026 & 358.056024 & -54.810258 & @xmath397 & @xmath398 & @xmath399 & + 14378 & 357.875627 & -54.892067 & @xmath400 & @xmath390 & @xmath401 & + 14844 & 357.899766 & -54.880469 & @xmath402 & @xmath403 & @xmath404 & + 17455 & 357.997121 & -54.822676 & @xmath402 & @xmath405 & @xmath406 & + 17729 & 357.875358 & -54.816995 & @xmath407 & @xmath408 & @xmath377 & + 15068 & 358.094352 & -54.876409 & @xmath409 & @xmath410 & @xmath369 & + 15994 & 357.763211 & -54.855887 & @xmath411 & @xmath412 & @xmath377 & + 12892 & 358.014272 & -54.926461 & @xmath413 & @xmath414 & @xmath369 & + 15697 & 357.897819 & -54.862968 & @xmath413 & @xmath415 & @xmath416 & @xmath417 + 12589 & 357.785585 & -54.933352 & @xmath418 & @xmath419 & @xmath420 & + 11976 & 357.893073 & -54.951394 & @xmath421 & @xmath422 & @xmath423 & + 14664 & 357.901167 & -54.885034 & @xmath424 & @xmath425 & @xmath369 & + 13901 & 357.824131 & -54.902094 & @xmath426 & @xmath427 & @xmath377 & + 14595 & 357.914211 & -54.886290 & @xmath428 & @xmath429 & @xmath430 & + 12863 & 357.874307 & -54.926847 & @xmath431 & @xmath432 & @xmath359 & + 15156 & 357.891357 & -54.874854 & @xmath433 & @xmath434 & @xmath435 & + 14825 & 357.922988 & -54.880749 & @xmath431 & @xmath436 & @xmath377 & + 12650 & 357.958048 & -54.931820 & @xmath437 & @xmath438 & @xmath377 & + 14407 & 357.917097 & -54.891402 & @xmath439 & @xmath440 & @xmath441 & @xmath442 + 14939 & 357.872276 & -54.878410 & @xmath439 & @xmath440 & @xmath359 & + 14944 & 357.913836 & -54.877816 & @xmath443 & @xmath444 & @xmath445 & + 14271 & 357.899268 & -54.896523 & @xmath446 & @xmath447 & @xmath250 & @xmath448 + 15403 & 357.908847 & -54.870362 & @xmath449 & @xmath450 & @xmath282 & @xmath451 + 15827 & 357.957606 & -54.860595 & @xmath452 & @xmath453 & @xmath454 & @xmath455 + 15400 & 357.866255 & -54.870713 & @xmath284 & @xmath456 & @xmath266 & @xmath457 + 14466 & 357.909595 & -54.890780 & @xmath458 & @xmath459 & @xmath460 & @xmath269 + 14492 & 357.914762 & -54.888447 & @xmath421 & @xmath461 & @xmath377 & @xmath462 + 13372 & 357.917399 & -54.914403 & @xmath463 & @xmath464 & @xmath465 & @xmath466 + 14505 & 357.870029 & -54.888283 & @xmath467 & @xmath468 & @xmath430 & @xmath451 + ccccccc 14193 & 357.895093 & -54.901998 & @xmath469 & @xmath470 & @xmath471 & @xmath472 + 15313 & 357.893518 & -54.875789 & @xmath473 & @xmath474 & @xmath475 & @xmath476 + 16682 & 357.903652 & -54.840904 & @xmath477 & @xmath478 & @xmath479 & @xmath480 + 13520 & 357.887606 & -54.911328 & @xmath481 & @xmath482 & @xmath483 & @xmath484 + 19352 & 357.902529 & -54.852090 & @xmath485 & @xmath486 & @xmath487 & @xmath488 + 15509 & 357.941448 & -54.869154 & @xmath339 & @xmath459 & @xmath359 & @xmath489 + 16409 & 357.890133 & -54.846245 & @xmath341 & @xmath490 & @xmath491 & @xmath492 + 16570 & 357.911876 & -54.843091 & @xmath360 & @xmath493 & @xmath494 & @xmath495 + 13423 & 357.960803 & -54.913826 & @xmath496 & @xmath497 & @xmath369 & @xmath498 + 13620 & 357.889293 & -54.909472 & @xmath413 & @xmath499 & @xmath500 & @xmath501 + 19257 & 357.902437 & -54.851578 & @xmath502 & @xmath503 & @xmath504 & @xmath505 + 16562 & 357.948746 & -54.841891 & @xmath506 & @xmath507 & @xmath508 & @xmath509 + ccccccccll @xmath167 & 1883 & 22.5 & 24.0 & 18.75 & 0.68 & @xmath510 & @xmath511 & 0.83 & 0.68 + @xmath96 & 7013 & 22.0 & 24.0 & 12.0 & 0.70 & @xmath512 & @xmath513 & 1.54 & 0.059 + @xmath2 & 3296 & 22.0 & 23.5 & 12.0 & 0.71 & @xmath514 & @xmath515 & 1.55 & 0.055 + @xmath3 & 2300 & 20.5 & 22.5 & 12.0 & 0.62 & @xmath516 & @xmath517 & 0.89 & 0.60 + + @xmath2+@xmath96 & 7995 & & & & 0.70 & @xmath518 & @xmath519 & 1.58 & 0.048 + @xmath2+@xmath96+@xmath3 & 8996 & & & & 0.70 & @xmath520 & @xmath521 & 1.48 & 0.077 + @xmath2+@xmath96+@xmath3+@xmath167 & 9424 & & & & 0.70 & @xmath522 & @xmath523 & 1.50 & 0.069 + @xmath2+@xmath96+@xmath3+sl(s ) & 8996 & & & & 0.70 & @xmath524 & @xmath525 & 1.48 & 0.077 + @xmath2+@xmath96+@xmath3+sl(sg ) & 8996 & & & & 0.70 & @xmath526 & @xmath527 & 1.48 & 0.077 + wl+sl+@xmath191+@xmath4 & 8996 & & & & 0.70 & @xmath528 & @xmath529 & 1.48 & 0.077 + @xmath167 & 1883 & 22.5 & 24.0 & 18.75 & 0.68 & @xmath530 & @xmath531 & 1.04 & 0.41 + @xmath96 & 7013 & 22.0 & 24.0 & 12.0 & 0.70 & @xmath532 & @xmath533 & 1.19 & 0.25 + @xmath2 & 3296 & 22.0 & 23.5 & 12.0 & 0.71 & @xmath510 & @xmath534 & 0.91 & 0.58 + @xmath3 & 2300 & 20.5 & 22.5 & 12.0 & 0.62 & @xmath535 & @xmath536 & 0.61 & 0.91 + + @xmath2+@xmath96 & 7995 & & & & 0.70 & @xmath532 & @xmath537 & 1.10 & 0.34 + @xmath2+@xmath96+@xmath3 & 8996 & & & & 0.70 & @xmath532 & @xmath538 & 0.80 & 0.71 + @xmath2+@xmath96+@xmath3+@xmath167 & 9424 & & & & 0.70 & @xmath539 & @xmath534 & 0.77 & 0.75 + lccccc a1 & @xmath540 & @xmath541 & @xmath542 & @xmath543 & @xmath544 + a2 & @xmath545 & @xmath546 & @xmath547 & @xmath548 & @xmath549 + a3 & @xmath550 & @xmath551 & @xmath552 & @xmath553 & @xmath554 + a4 & @xmath555 & @xmath556 & @xmath557 & @xmath558 & @xmath559 + | we report on the serendipitous discovery in the blanco cosmology survey ( bcs ) imaging data of a @xmath0 galaxy that is being strongly lensed by a massive galaxy cluster at a redshift of @xmath1 .
the lens ( bcs j2352 - 5452 ) was discovered while examining @xmath2- and @xmath3-band images being acquired in october 2006 during a bcs observing run .
follow - up spectroscopic observations with the gmos instrument on the gemini south 8 m telescope confirmed the lensing nature of this system . using weak plus strong lensing , velocity dispersion , cluster richness @xmath4 , and fitting to an nfw cluster mass density profile ,
we have made three independent estimates of the mass @xmath5 which are all very consistent with each other .
the combination of the results from the three methods gives @xmath6 , which is fully consistent with the individual measurements .
the final nfw concentration @xmath7 from the combined fit is @xmath8 .
we have compared our measurements of @xmath5 and @xmath7 with predictions for ( a ) clusters from @xmath9cdm simulations , ( b ) lensing selected clusters from simulations , and ( c ) a real sample of cluster lenses .
we find that we are most compatible with the predictions for @xmath9cdm simulations for lensing clusters , and we see no evidence based on this one system for an increased concentration compared to @xmath9cdm .
finally , using the flux measured from the [ oii]3727 line we have determined the star formation rate ( sfr ) of the source galaxy and find it to be rather modest given the assumed lens magnification . |
Slut-shaming Bridget Kelly: How she ranks among history’s greatest political sluts
By Tony Ortega
Friday, March 28, 2014 12:12 EDT
Thursday night, Rachel Maddow marveled at the $1 million price tag shouldered by New Jersey’s taxpayers for an “investigation” of Governor Chris Christie by a law firm hand-picked by the governor himself. By now you’ve heard the boring stuff — Christie’s lawyers found that he had nothing to do with the George Washington Bridge scandal, yadda, yadda, yadda. But Maddow pointed out that the really juicy stuff to come out of the 344-page report was aimed at two women, neither of whom cooperated with the investigation.
The investigation found that Hoboken mayor Dawn Zimmer’s claims that she was strong-armed over Hurricane Sandy relief funds were “demonstrably false.” How did the sleuths working for Christie determine that? As Maddow pointed out, the investigative team dug up photos of Zimmer at a public event which took place shortly after she had been reminded by one of Christie’s commissioners that she was expected to “play ball” and support a development deal in return for more relief funds. After being reminded that she was expected to come through on the scummy quid pro quo, Zimmer took part in a taped PBS political panel. And then, photo evidence proved, she yawned.
Imagine that. During a PBS taping.
This, Christie’s crack squad decided, was clear evidence that Zimmer was a lying sack of shit.
“A person does not normally yawn when being threatened, coerced, or spoken to improperly,” the report said.
Maybe it’s just us, but we have a hard time seeing a male politician treated this way.
And that becomes abundantly more clear when you see how the report treated another woman who refused to be interviewed by the investigative team — Bridget Anne Kelly, Christie’s former deputy chief of staff famous for her August 2013 e-mail that said, “Time for some traffic problems in Fort Lee.” A month later, access lanes from Fort Lee to the GWB were shut down for four days, leading to gridlock in the town of Biblical proportions.
However, despite all the subpoenas and hearings and barrels of ink spilled over the scandal since then, we’re no closer to finding out why Kelly thought it was a good idea to create such a traffic mess for Fort Lee. Who was being targeted, and on whose behalf?
The report did contain one new solid piece of information which might help answer the first part of that question. The night before she sent that fateful August e-mail, Kelly got confirmation that Fort Lee mayor Mark Sokolich would not be endorsing her boss for re-election. That timing helps bolster what has been from the beginning the prevailing theory for the lane shutdown — it was political payback for Sokolich’s refusal to endorse Christie. But it still doesn’t really tell us why Kelly thought it made sense to punish Sokolich this way when his endorsement meant so little and Christie was just trying to run up the score in an election he had in the bag.
Again, what was Kelly thinking? Now, Christie’s hired guns believe they have the answer: She was a woman scorned.
Repeatedly, in the voluminous report, there are mentions that Kelly briefly dated Bill Stepien, Christie’s former campaign manager, and that the relationship had ended by August, “apparently at Stepien’s choice.” (Kelly and Stepien didn’t talk to Christie’s lawyers, and the report doesn’t say who supplied the investigative team with their information.)
The message is loud and clear from Christie’s hired exonerators: This was all Bridget Kelly’s idea, because she was out of her mind after being dumped.
“This is called ‘slut-shaming’,” Maddow said on her program Thursday night. And she’s absolutely correct.
Chris Christie’s whitewash report exonerates him by slut-shaming the woman who, so far, has not said a word about the scandal and who could, presumably, open up and make things pretty uncomfortable for the governor. On Thurday, ABC’s Diane Sawyer asked Christie if Kelly could ‘blow the report out of the water’ if she opened up.
“Not credibly, no,” he answered.
Well of course not, who’s going to take a slut like Bridget Kelly seriously after the shaming she got from Christie’s hired guns?
The only question that remains is, how does Bridget Kelly stack up against history’s other women slut-shamed for political gain.
Sandra Fluke testified to Congress early in 2012 that a health insurance program like Obamacare should include birth control. For that, Rush Limbaugh labeled her a prostitute and a slut: “She essentially says that she must be paid to have sex — what does that make her? It makes her a slut, right? It makes her a prostitute. She wants to be paid to have sex. She’s having so much sex she can’t afford the contraception. She wants you and me and the taxpayers to pay her to have sex.” Limbaugh paid a price for that utterance. His advertised flew like rats from a sinking ship. Fluke, meanwhile, is now running for a state senate seat in California.
Wendy Davis became an overnight sensation when the Texas state senator filibustered a restrictive abortion bill for eleven hours. The bill eventually became law anyway, but Davis is now running for governor based on her new fame. Her stand for women’s rights, however, predictably made her the target of ugly personal attacks: conservative clown Erick Erickson dubbed her “abortion Barbie,” and her personal story — raising two children while finishing grad school and going through a divorce — has been twisted to make her out to be a heartless opportunist.
Anita Hill was called to testify during the confirmation hearings of Clarence Thomas, who had been nominated to the Supreme Court by President George H. W. Bush in 1991. Hill had been interviewed by the FBI about Thomas, and now Congress demanded to hear her testimony: That her boss, Thomas, had sexually harassed her. What the Senate Judiciary Committee didn’t hear — thanks in part to its chairman, Joe Biden — was the testimony of four other women who all backed up Hill’s version of events. Instead, Hill had to go through the usual “woman scorned” bullshit as Thomas bellyached about a “high-tech lynching” and was ultimately confirmed.
We’re certain you can think of more women who have been slut-shamed in the name of politics. Who would you put on this list? And how would you order them?
[Image: Bridget Kelly with her attorney, still from The Rachel Maddow Show] ||||| Not Cool
The Bridgegate report commissioned by Chris Christie included gratuitous details about the personal life of one of his staffers.
When the results of the internal Bridgegate investigation, commissioned by New Jersey Governor Chris Christie were released Thursday, it included a curious revelation. Bridget Anne Kelly, Christie’s former Deputy Chief of Staff whom he fired on January 9 after the release of her smoking gun “time for some traffic problems in Fort Lee” email, had been involved in an affair with Bill Stepien, Christie’s former campaign manager.
The report, which cost New Jersey taxpayers $1 million, states that “Kelly and Stepien became personally involved, although, by early August 2013, their personal relationship had cooled, apparently at Stepien’s choice, and they largely stopped speaking.”
State Senator Loretta Weinberg, one of two co-chairs of the joint legislative committee investigating Bridgegate, told The Daily Beast that she believes this was an attempt to assassinate the character of Kelly.
“Maybe that’s what’s making me so angry,” Weinberg said in a phone call Thursday. “They’re talking about ‘a personal relationship’ and they put in the report that Mr. Stepien was the one who ended it—how do they know that? How do they know that? And was that done to add to the credence that this was some crazy woman, some woman who is no longer in control of her emotions?”
When asked why the affair was mentioned at all, Randy Mastro, an attorney at the white shoe firm of Gibson, Dunn & Crutcher, which was hired to do the investigation, told the media at a press conference, “the relevance is that it may explain a lack of communication between [Kelly and Stepien].”
Weinberg scoffed at that answer. “And what does that have to do with anything? If there were no emails, there were no emails! Maybe there were [also] no emails between two other people. What does that mean? That they all had relationships and they broke up?”
Even if Mastro could make the case that explaining the lack of communication between Kelly and Stepien was necessary in his report, that does not explain why the report stated that Stepien had broken up with Kelly.
The Daily Beast reached out to Mastro to find out if there was a legitimate reason to include that fact. He responded, “As I explained at yesterday’s press briefing, these facts are unquestionably relevant because they help 'explain a lack of communication between the two of them during a critical period' when Kelly gave the “go-ahead” to David Wildstein, a Christie appointee at the Port Authority, [to do the ‘traffic study’].” Mastro said that including that could explain how Kelly and Stepien “approached this issue and caused each of them to change the way in which they communicated with each other.”
Mastro also said that the “premise” of the question from The Daily Beast, that the inclusion of the fact that Stepien broke up with Kelly seemed gratuitous, and aimed to humiliate Kelly in a sexist manner, “is wholly unfounded.”
A spokesman for Governor Christie, Kevin Roberts, declined to comment on the matter altogether, stating “For questions on what was included or not included [in the report] you would need to go to Gibson Dunn, who conducted the investigation and authored the report.”
In addition to informing us that Kelly had been dumped by Stepien, Christie’s internal Bridgegate report says that Kelly “seemed emotional,” and that she was “habitually concerned with how she was perceived by the governor.” |||||
New Jersey Governor Chris Christie’s former deputy chief of staff Bridget Anne Kelly makes her way through a crush of media with her attorney as she arrives at Mercer County Court in Trenton, New Jersey, March 11, 2014. REUTERS/Mike Segar (UNITED STATES – Tags: POLITICS)
The 360-page report released Thursday by New Jersey Gov. Chris Christie’s legal team that examines the George Washington Bridge lane closures in Fort Lee, N.J. is getting backlash because of its depiction of Bridget Anne Kelly, Christie’s former deputy chief of staff, as an overwhelmed, possibly scorned woman who was nonetheless so devious that she, alone, masterminded the scandal that has rocked the governor’s office.
It was during his marathon press conference to address charges that the bridge closings were politically motivated that Christie announced that he had fired Kelly, saying he had no idea someone who worked for him had been “so stupid and so deceitful.”
Kelly, has not responded to Christie’s initial claims, and has refused to cooperate with the investigation. She also has not responded to the report, whose description of Kelly’s actions seems to contradict much of what’s already on the public record about the divorced mother of four who sent the “time for some traffic problems in Fort Lee,” e-mail on August 13.
The report, which attempts to explain the Fort Lee lane closures, delves into Kelly’s personal life, suggesting it might have affected her judgment. For instance, it notes that she had a personal relationship with Bill Stepien, Christie’s former campaign manager, but that he dumped her.
From the report:
And when speculation of political retaliation surfaced as a reason for this lane realignment, Mayor Sokolich said he found it “incomprehensible that there’s any truth whatsoever to these rumors.” Something happened to change this dynamic dramatically, however, in August 2013. By that time, Kelly had become Deputy Chief of Staff, assuming the post left vacant by her predecessor, Stepien, who had departed in April 2013 to run the Governor’s re-election campaign. Because Stepien was her “benefactor,” Kelly relied heavily on him during this transition. And at some point after Stepien’s departure to run the campaign, Kelly and Stepien became personally involved, although, by early August 2013, their personal relationship had cooled, apparently at Stepien’s choice, and they largely stopped speaking.
Reaction from the news media has been stinging.
The Daily Beast called it “The Slut-Shaming of Bridget Anne Kelly”
The Raw Story put it this way in a headline: “Slut-shaming Bridget Kelly: How she ranks among history’s greatest political sluts”
And The New York Times reports that Kelly’s friends think the report is sexist and off-base.
This from twitter:
Pretty messy under that bus @ChrisChristie threw his colleagues under #slutshaming — mia farrow (@MiaFarrow) March 28, 2014
Kevin Marino, Stepien’s lawyer, has said that the report exculpates his client and that the personal details amount to “gratuitous presence dropped into the middle of this report can only be done for purpose of creating an alternative headline.”
New Jersey state Sen. Loretta Weinberg (D) said she was angered by the personal revelations in the report.
“I am the last person to be an apologist for Bridget Kelly, but it was gratuitous, it was sexist, it was inappropriate,” she said in a telephone interview. “They seem to want to suggest that if you were scorned by your partner, that of course the next logical thing is that you go out and close a bridge.”
Randy Mastro, a lead lawyer on the report, said in a press conference that the personal details about the relationship were included to explain the lack of communication between Stepien and Kelly, and in an interview with the Daily Beast said that the notion that the report set out to humiliate Kelly in a sexist way “is wholly unfounded.”
UPDATE: At a Friday press conference, Christie responded to a question about whether the report was “fair” to his former staffer. He said that the report laid out the facts as investigators found them and “how anyone wants to interpret those it’s up to your interpretation.” Another journalist asked why the report didn’t comment on the emotional side of the men in the same way it detailed Kelly’s state of mind, and Christie said that the he assumes that the investigators didn’t have documents or testimony that gave a window in the emotional side of the others in the report.
UPDATE: Kelly’s defense lawyer, Michael Critchley, provided a statement to the Star-Ledger, Friday night, writing that his client “worked tirelessly to pursue the goals of the Office during her tenure” and he criticized the tone of the report:
“The report’s venomous, gratuitous, and inappropriate sexist remarks concerning Ms. Kelly have no place in what is alleged to be a professional and independent report.” | – Chris Christie surely knew that the report exonerating him in the Jersey bridge scandal would be called biased because he himself commissioned it. But sexist, too? That's the gist of criticism making the rounds because of the report's treatment of former Christie aide Bridget Anne Kelly. Investigators wrote that Kelly "seemed emotional" and was “habitually concerned about how she was perceived by the governor"—a tone notably absent in descriptions of the men in the report, Kelly's friends point out to the New York Times. The report, in the words of the Times, "doubles down on a strategy of portraying Ms. Kelly as duplicitous, weeping frequently and dependent on men for approval and stability." What seem to be rankling critics most is that investigators found it necessary to mention not only that that Kelly had a brief relationship with Christie's former campaign manager, Bill Stepien, but that it was Stepien who broke it off. “Maybe that’s what’s making me so angry,” state Sen. Loretta Weinberg tells the Daily Beast. “They’re talking about ‘a personal relationship’ and they put in the report that Mr. Stepien was the one who ended it—how do they know that? How do they know that? And was that done to add to the credence that this was some crazy woman, some woman who is no longer in control of her emotions?" (Both the DB and a column at Raw Story use the phrase "slut-shaming" in their headlines.) Christie defended the report today when asked whether it was fair to Kelly, reports the Washington Post. The report lays out the facts, he said, and “how anyone wants to interpret those, it’s up to your interpretation.” (In another Bridgegate development, the head of the Port Authority resigned today, reports the Wall Street Journal. |
lipases are enzymes that belong to the class of hydrolases and are involved in catalyzing the hydrolysis of triglycerides to fatty acids and glycerol , this reaction occurs at the oil - water interface . besides , they are also capable of catalyzing the reverse reaction , that is , ester synthesis , in water - restricted environments .
transesterification and resolution of racemic mixtures are also reactions that could be facilitated by lipases .
such a versatile nature has paved the way for their application in diversified industries including food , dairy , cosmetic , detergent , and pharmaceuticals .
the environmental applications of the enzyme are also innumerable , where they break down fat , oil , and greasy material in the wastewater .
these constituents could pose problems in the sewers as well as the treatment plant , impeding oxygen transfer in aerobic biological treatment systems .
lipases can be procured from plant , animal [ 58 ] , and microbial sources .
however , microbial lipases have gained increasing attention due to their stability and high substrate specificity [ 9 , 10 ] . in the microbial community
, lipolytic activity is exhibited by several bacteria , fungi , yeasts , and among these , filamentous fungi are the ideal candidates for industrial - scale lipase production . aspergillus , penicillium , mucor , rhizopus , geotrichum , and so forth are some of the fungal genera whose lipase activities have been widely investigated [ 1113 ] .
new organisms continue to be screened , with hopes of stumbling upon isolates with extremophilic properties that can survive harsh conditions and produce enzymes with unique characteristics desirable for specific industrial applications . after this initial step of isolation and screening , optimization of enzyme production by the isolate is warranted .
ph , temperature , aeration rate , incubation period , inoculum level and age , carbon , nitrogen sources and trace elements in the medium , and so forth are some of the physicochemical factors that influence enzyme production and these have to be optimized .
medium optimization has conventionally been done by varying one factor at a time ( ofat ) , and it is workable as long as the production process is influenced by a limited number of variables .
even then , it fails to assess the interaction effects of those variables and becomes quite cumbersome , entailing a large number of trials when several variables are to be considered .
hence , researchers seek the aid of statistical tools such as placket burman and response surface methodology ( rsm ) for effective optimization of their production media [ 15 , 16 ] .
fungal strains isolated from dairy wastewater were screened for lipase activity ; physicochemical parameters having significant impact on lipase production were identified through the classical ofat approach , and later rsm ( box - behnken design ) was applied in determining the optimal concentrations as well as interaction effects of those parameters .
p - nitrophenyl palmitate ( p - npp ) was purchased from sigma aldrich , usa . all other chemicals and reagents used were of analytical grade and purchased from hi - media , india .
it was stored at 4c and used as a source of possible lipolytic fungal strains .
the effluent sample was subjected to serial dilution and then plated on potato dextrose agar ( pda ) plates for fungal isolation .
colonies on the plate that showed morphological difference were subcultured on pda slants and maintained as pure culture .
such pure cultures were inoculated into glucose - yeast extract - peptone ( gyp ) broth supplemented with 2% olive oil and containing trace amounts of mineral salts ( glucose 20 g / l , yeast extract 10 g / l , peptone 10 g / l , ch3coona3h2o 10 g / l , mgso4 0.3 g / l , mnso4 0.1
they were cultured at room temperature for 48 hours in a rotary shaker ( 90 rpm ) after which they were centrifuged at 10,000 g for 10 minutes at 4c .
the supernatant was used as the crude enzyme extract , whose activity was assayed by using p - npp as substrate ( elico uv - vis spectrophotometer ) . for the enzyme assay , 30 mg of p - npp was dissolved in 10 ml of isopropanol ( solution a ) ; 0.1 g of gum arabic and 0.4 ml triton x-100 were added to 90 ml of 50 mm tris - hcl buffer , ph 8 ( solution b ) .
to 9 ml of this solution , 1 ml of enzyme was added and the mixture incubated at 32 2c for 15 min .
its absorbance was measured at 410 nm , the absorption coefficient of p - nitrophenol at 410 nm is 0.0148 .
one unit of lipase activity ( u ) was expressed as mol of p - nitrophenol released per minute under the assay conditions .
growth conditions and chemical components were varied one at a time in the gyp medium and their impacts on lipase production were studied .
the incubation time of the culture was varied in the range of 1296 hours ; the incubation temperature in the range of 3060c ; initial ph in the range of 4.012.0 .
the chemical composition of the growth medium was then altered in the following ways : glucose was substituted with starch , sucrose , or maltose ( 2% ) ; nitrogen source was replaced by other organic ( 1% ) or inorganic ( 0.5% ) sources , namely , soy peptone , casein , sodium nitrate , ammonium sulfate , or ammonium chloride ; olive oil was replaced with gingelly , sunflower , groundnut , palm , or tributyrin oil ( 2% ) ; finally , the basic gyp medium was augmented with trace amounts of different inorganic ions ( ca , fe , zn , ba , or mg ) .
the interactive effects of three significant factors a ( oil source ) , b ( nitrogen source ) , and c ( inorganic ion ) on the response , namely , lipase production were determined statistically using rsm . a box - behnken design developed by the design expert software , version 8.0.7.1 ( stat ease inc .
each one of the above independent variables a , b , and c was taken at a central coded value considered as zero and studied at three different levels .
the values of these variables in actual and coded forms are presented in table 1 .
a matrix consisting of 17 experiments with 5 replicates at the centre point generated by the software was applied for maximizing the lipase production .
production was carried out in 250 ml erlenmeyer flasks containing 100 ml of the production medium ( ph 8.0 ) .
the flasks were sterilized by autoclaving at 120c for 20 min , inoculated with the culture under aseptic conditions , and incubated at 40c for 72 h , in an orbital shaker set at 90 rpm . at the end of the incubation period
, lipase assay was performed using the cell - free supernatant and activity was recorded as the response ( dependent variable ) .
the following second - order polynomial equation describes the relationship between the dependent and independent variables :
( 1)y=0+1a+2b+3c+11a2+22b2+33c2+12ab+13ac+23bc ,
where , y is the predicted response , 0 is the intercept , 1 , 2 , 3 , are the linear coefficients , 11 , 22 , 33 , are the squared coefficients , and 12 , 13 , 23 are the interaction coefficients . the model was statistically analyzed .
analysis of variance ( anova ) involved fischer 's f test to judge the model 's overall significance , associated probability values , and coefficient of determination to measure the regression model 's goodness of fit .
the fitted polynomial equation was further expressed in the form of 3d and contour plots which depicted the interactions graphically .
several fungal colonies grew on the pda plates that were inoculated with the serially diluted wastewater sample .
19 morphologically different colonies were subcultured and the resulting pure cultures were preserved on pda slants overlaid with liquid paraffin .
p - npp assay of these isolates after cultivation in the production medium revealed appreciable activities for 10 ( figure 1 ) and negligible activities for the rest ( data not shown ) .
the isolate skwf7 , which showed a maximum activity of 36.9 u / ml was identified to be fusarium solani by the indian agricultural research institute ( iari ) , new delhi .
further experiments on medium optimization were performed with this isolate . when the physicochemical parameters were varied one at a time and their impact on lipase production was investigated , the following results were obtained
. enzyme production steadily increased with increasing incubation time of the culture and reached a plateau at 72 hours ( figure 2 ) .
similar or longer incubation periods have been widely reported for fungi . in the case of mucor sp .
highest enzyme production was recorded with an incubation temperature of 40c ( figure 3 ) . upon altering the culture medium ph ,
it was witnessed that there was good production in the range of 4.08.0 , with the production peaking at 8 and rapidly falling thereafter ( figure 4 ) .
a strain of aspergillus niger showed maximum enzyme production after 96 h of growth in a medium with an initial ph of 7.0 .
the disaccharide sucrose was found to be the best carbon source ( figure 5 ) .
the inducible nature of lipases necessitates the presence of a lipid substrate in the medium and in this case , induction of enzyme synthesis was best favoured by the presence of palm oil ( figure 6 ) .
a combination of 2% olive oil and 2% glucose was demonstrated to be conducive for lipase production by a. niger .
the organic nitrogen source casein and inorganic source ammonium sulphate resulted in maximum lipase production ( figure 7 ) .
ca best stimulated the enzyme production by up to 20% , in comparison to a medium devoid of trace elements ( figure 8) .
the presence of mn had no effect , while ba had a negative impact on enzyme production .
rsm incorporates the interaction effects of variables and aids us in simultaneously optimizing several process parameters within a minimal number of experimental runs .
such statistically assisted experimental designs can lead to significantly enhanced production . in our investigation ,
palm oil ( a ) , ( nh4)2so4 ( b ) and caco3 ( c ) , which were inferred to be significant media constituents based on ofat studies were selected for optimization through the box - behnken design .
second - order polynomial equation describing the empirical relationship between the independent variables and response is given underneath :
( 2)y(lipase activity u / ml)=+67.2052719.48972a + 3.82302b36.39877c + 0.11778ab0.030556ac 0.12840bc+3.73469a2 0.34093b2 + 30.19136c2 .
the anova results and diagnostic case studies are given in tables 2 and 3 , respectively .
the p value serves as a tool for checking the significance of each of the coefficients and is indicative of the interaction strength of each independent variable .
low values of p < 0.05 indicate high significance of the corresponding coefficients . in general , larger t , f and
smaller p values indicate that the corresponding coefficient terms are significant . subjecting our model to anova showed an f value of 1704.58 and a p value < 0.0001 which indicate that the model is highly significant .
all three linear coefficients , squared coefficients , and one interaction coefficient ( ab ) are significant , as evidenced from low p and high f values .
r
value gives a measure of how much variability in the observed response can be explained by the experimental parameters and their interactions .
when expressed as a percentage , it implies that a total variation of 99.95% in enzyme activity can be attributed to the independent variables and only 0.05% can not be ascribed to them .
the predicted r of 0.9927 is in acceptable agreement with the adjusted r of 0.9989 .
the adjusted r arranges the r values for the sample size and for the number of variables in the model .
adequate precision measures signal - to - noise ratio and detects which experimental parameters generate signals that are large in comparison to the noise .
a ratio greater than 4 is desirable . in this case , the value obtained is 327.78 and is thus indicative of an ample signal .
the regression equation is expressed graphically in the form of contour plots which depict the interactions among the independent variables and their influence on enzyme production .
the contour plots might be elliptical mounds , saddle points , or rising ridges . here , contour plots were generated by varying the levels of two factors while keeping the third one constant .
the plot of oil concentration versus calcium carbonate concentration ( figure 9(a ) ) is elliptical in nature indicating significant interactions between the two variables .
the plot between ( nh4)2so4 and oil concentrations figure 9(b ) and the one between ( nh4)2so4 and caco3 concentrations figure 9(c ) are not elliptical in nature , but saddle points , indicating that there are fewer interactions between them .
13 and the levels of the independent variables were 5% oil ( + 1 ) , 5.5 g / l ( nh4)2so4 ( 0 ) , and 0.1 g / l caco3 ( 1 ) . this is a 1.7-fold increase in comparison with the preoptimization maximum of 42.3 u. this goes to prove that the developed model has resulted in appreciable enhancement of enzyme production , thereby improving the feasibility of the process . earlier , central composite design has been applied to optimize lipase production by the yeast candida cylindracea using two different carbon sources and a yield of 17.30 u / ml using glucose as carbon source and 47.25 u / ml using olive oil as carbon source was obtained .
lipase production by candida rugosa has been optimized using rsm - based design and cheese whey was used as a substrate for this . from the experimental design it was concluded that a combination of brewery product , yeast and malt extract , tween 80 , and olive oil with cheese whey resulted in a 287% increase in enzymatic activity . a medium comprised of soyabean meal 0.77% ( w / v ) , ( nh4)2so4 0.1 m , kh2po4 0.05 m , rice bran oil 2% ( v / v ) cacl2 0.05 m , peg 60000.05% ( w / v ) , nacl 1% ( w / v ) , inoculum 1% ( v / v ) , ph 3 , incubation temperature 35c , and incubation period of 5 days has been identified to be the optimal conditions for lipase production by aspergillus awamori . in another study , a medium containing 0.45% ( w
/ v ) peptone , 0.65% ( v / v ) tween-80 , and 2.2% ( v / v ) inoculum has been recommended for a maximal lipase production of 20.6 u / ml by candida cylindracea .
the objective of the validation study is to demonstrate that the polynomial expression could correctly predict and describe the response function .
the validation report generated by the design expert software is given in table 4 , which predicts a maximum lipase activity of 73.65 u / ml .
this work has culminated in the isolation of several fungal strains from dairy effluent , of which fusarium solani skwf7 exhibited pronounced extracellular lipolytic activity .
the physical and chemical parameters influencing enzyme production by this isolate were varied one at a time and their impact was probed , revealing the ones that lead to a heightened enzyme production .
the feasibility of using statistically based experimental design to simultaneously screen multiple variables and optimize fermentation conditions for increasing the enzyme yield was also demonstrated .
based on this design , 5% ( v / v ) , 5.5 g / l , and 0.1 g / l were found to be the optimal concentrations of palm oil , ( nh4)2so4 , and caco3 , resulting in a 1.7-fold increase in enzyme production .
the model was statistically significant as is evident from low p and high f values .
thus , it can be concluded that the model can potentially be applied for lipase production by fusarium solani .
based on the promising results obtained in this shake - flask study , production in a bioreactor and the utilization of cheap substrates derived from waste materials are to be taken up in future studies , with an objective of exploring scale - up feasibility , bringing down production costs and thereby augmenting the economic viability of the process . | the optimization of extracellular lipase production by fusarium isolani strain skwf7 isolated from dairy wastewater was carried out in this study .
initially , the physicochemical factors significantly influencing enzyme production were studied by varying one - factor - at - a - time ( ofat ) . a mesophilic temperature of 40c , alkaline ph of 8 , and incubation period of 72 hours were found to be the optimal conditions for lipase production . among the media components , the disaccharide sucrose acted as the best carbon source ; palm oil as the best inducing lipid substrate ; casein and ( nh4)2so4 as the best organic and inorganic nitrogen sources ; ca2 + ion as the best trace element . in the next phase of work ,
statistical optimization of medium components was performed by employing the box - behnken design of response surface methodology ( rsm ) .
the optimum concentrations of three significant factors , namely , palm oil , ( nh4)2so4 , and caco3 were determined by this method to be 5% ( v / v ) , 5.5 g / l , and 0.1
g / l , respectively .
rsm - guided design of experiments resulted in a maximum lipase production of 73.3 u / ml , which is a 1.7-fold increase in comparison with that obtained in the unoptimized medium .
these results point towards the success of the model in developing a process for the production of lipase , an enzyme of enormous industrial significance . |
female sexual dysfunction is a serious , common , multifactorial general health problem which is usually neglected in the general population while affecting the women 's quality of life to a great extent ( 1 ) .
lack of sexual health and security will result in anger , excessive rage , depression , drug abuse , lack of physical and psychological capability for parenting and child care , lack of sufficient skills for having a healthy emotional relationship , inability to flourish in the society , infanticide and even death ( 2 ) . in one study conducted in hong kong in 2007
, zhang interviewed 1510 chinese women who were between 19 and 49 years old and showed that 37.9% of the participants suffered from at least one sexual disorder ( 3 ) .
one other study in egypt showed the prevalence of sexual dysfunction to be 76.9% among the studied women , with low sexual desire being the most prevalent one ( 66.4% ) .
besides , as the women 's age increased , the prevalence of sexual disorders increased , as well ( 4 ) .
one study on kurdish women in iran indicated that 77% of the studied participants had one sexual disorder ( 5 ) .
another study in iran also revealed that 10.5% of women had never experienced orgasm ( 6 ) . in the study that safarinejad ( 2006 ) conducted on 20 - 60 year old women in iran , the prevalence of low sexual desire , lack of sexual arousal , lack of orgasm , and pain during intercourse
was reported as 35% , 30% , 37% , and 26% , respectively ( 7 ) . up to now , most studies regarding the pharmacological treatments for sexual dysfunction have been conducted on males and female sexual dysfunction has been less taken into account ( 810 ) . recently ,
pharmacological treatments have been considered for female sexual dysfunction mainly focusing on improvement of androgen deficiency , increase of blood flow to the genital area and stimulation of the central nervous system ( 11 ) .
estrogen , progesterone , and testosterone are the main effective hormones in females sexual response ( 12 ) .
in addition , androgen deficiency is one of the main causes of female sexual dysfunction ( 13 ) .
nonetheless , testosterone has been less welcomed due to its side - effects , including hirsutism and acne ( 9 , 14 ) . according to some researches , sildenafil citrate is effective in treatment of orgasm as well as arousal disorders and increase of females sexual experiences ( 1518 ) .
sildenafil citrate is among the phosphodiesterase type 5 ( pde5 ) inhibitors which improve female sexual dysfunction through increasing blood flow to corpus cavernosum of clitoris , vagina and labia minor ( 1517 , 1925 ) .
however , in rare cases , its consumption might be accompanied by complications , such as mild headache , urinary tract infection and nausea ( 14 ) .
complementary and alternative medication ( cam ) is also used in treatment of sexual disorders ( 26 ) .
ginseng which is a chinese traditional medication is one of the effective herbal medicines in treatment of sexual disorders ( 2728 ) .
however , yohimibine has been shown to be more effective in treatment of sexual dysfunction in males as compared to females ( 2931 ) . in folk medicines ,
elaeagnus angustifolia ( elaeagnaceae ) is a mediterranean medicine representative of the family elaeagnaceae , commonly named oleaster , which is cultivated in north american , eurasia as far southwards as malaysia , australia , northern regions of asia to the himalayas and europe and for centuries in the desert and sub desert regions of western asia including iran ( 3235 ) .
a previous study showed that e. angustifolia flower and its derivatives had antibacterial and antifungal properties .
it also led to cutaneous wound healing by increasing re - epithelialization and collagen deposition ( 31 ) .
e. angustifolia flower is one of the herbal medications which , according to traditional medicine , is hot and dry , aromatic , and can stimulate sexual activity especially in young girls and women ( 36 ) .
it is also believed to have antioxidant effects ( 37 ) . due to its analgesic and anti - inflammatory effects ,
e. angustifolia extract is used in oils for external application ( 38 ) . moreover , one study showed e. angustifolia ointment to be effective in treatment of some skin disorders ( 39 ) .
other studies have also confirmed that the fruit core and leaves of this plant had analgesic and anti - inflammatory effects ( 4043 ) .
furthermore , one study evaluated the effect of aqueous and alcoholic extracts of e. angustifolia on intestinal smooth muscle relaxation in mice .
it indicated that the presence of flavonoids in the fruit was effective in intestinal smooth muscle relaxation .
therefore , the researcher suggests that this plant is a suitable candidate for treatment of muscle - skeletal disorders ( 40 ) due to its muscle relaxant effect . on the other hand ,
e. angustifolia has been found to contain flavonoid components and some flavones , such as chrysin , ( 5 , 7-dihydroxyflavone ) which have a partial agonistic effect on benzodiazepine receptors .
central benzodiazepine receptor ( bdz - r ) agonists have been known to induce multiple effects including anxiolytic , myorelaxant , anticovulsant , hypnotic and amnestic effects ( 4446 ) .
these two folk indications , anti - rheumatoid , anti - tetanus activities ( 40 ) , anxiolytic , myorelaxant effects acting on central benzodiazepine receptors of flavonoid found in e. angustifolia , may make this plant a suitable candidate for inducing muscle relaxant activity for sexual dysfunction . up to now
however , most of these studies have focused on the prevalence and types of sexual disorders and have paid less attention to the treatment dimensions , including training , consultation and pharmacotherapy .
hence , the present study aimed to compare the effects of e. angustifolia flower extract and sildenafil citrate on female orgasmic disorder in the women referring to selected gynecology clinics affiliated to shiraz university of medical sciences , shiraz , iran .
based on the study objectives and the previous studies conducted on the issue , considering error rate of 5% , power of 80% , minimum mean difference of 0.6 , and variance of 0.92 . a sample size of 126-subjects
overall , out of the 140 qualified women entered into the study , 125 ones ( 41 in the e. angustifolia group , 42 in the sildenafil citrate group , and 42 in the control group ) completed the study . the study population included 18 - 40 year old women suffering from sexual dysfunction .
the health centers were selected through stratified sampling and convenience sampling was used to select the women at each center .
then , the subjects were divided into e. angustifolia flower , sildenafil citrate , and control groups using stratified block randomization .
the inclusion criteria of the study were obtaining scores more than 22 in female sexual function index ( fsfi ) , having normal menstruation , not being pregnant , not breastfeeding , without the history of heart attack , hypertension , and cardiovascular diseases , not consuming the medications which are effective in sexual function such as common antidepressants , not suffering from dyspareunia and vaginismus , not being menopausal , with the history of different types of headaches such as migraine , not using hormone drugs particularly oral contraceptive pills and lack of drug or alcohol abuse .
on the other hand , the exclusion criteria of the study were showing allergic reactions to medicines and not being able to continue consuming the drugs for any reason .
the data were collected through demographic information form , fsfi , and measurement of tsh and prolactin .
fsfi which contains 19 items evaluates female sexual function in 6 domains of sexual desire , arousal , lubrication , orgasm , satisfaction and pain .
the women were required to answer the questions according to their sexual desire and function during the past 4 weeks . in general , the scores 28 were considered as sexual dysfunction .
nevertheless , since assessment of pain ( 6 points ) was omitted from the present study , score of 22 was considered instead of 28 .
the reliability of the whole questionnaire and the subscales was confirmed by cronbach 's alpha 0.70 .
moreover , investigation of the validity of the persian version of this questionnaire indicated a significant difference between the total mean score and the mean scores of the subscales in the two groups ( p0.001 ) ( 4748 ) . after obtaining written informed consents , tsh and prolactin
were assessed in all the participants in order to reject thyroid and prolactin disorders which are the secondary causes of sexual dysfunction . in this study
, the samples were selected through convenience sampling and were randomly allocated into two intervention groups and a control group .
the first intervention group had to consume 4.5 gr of e. angustifolia extract in two divided doses ( 2 capsules every 12 hr ) for 35 days .
the e. angustifolia capsule dosage was determined based on other studies conducted on the issue ( 4950 ) and a pharmacognosy advisor . in the second group ,
the dosage of sildenafil citrate was determined based on the previous studies most of which have used 50 and 100 g tablets ( 16 , 5153 ) .
e. angustifolia capsules were made in the pharmacology department under the supervision of a professional counselor .
moreover , the placebo was prepared from starch in similar packages to e. angustifolia capsules .
the control group received the placebo which they were required to consume for 35 days ( 2 tablets every 12 hours ) .
the participants were followed up twice a week through short message sending ( sms ) service and once a week through phone contact .
after the intervention , the women completed fsfi . finally , the data were entered into the spss statistical software ( version 18 ) and analyzed using paired t - test , one - way anova , and bonferroni post - hoc test . besides , p<0.05 was considered statistically significant .
this research project was approved by the local ethics committee of shiraz university of medical sciences and written informed consents were obtained from all the participants . in addition , the control group was provided with the results after completion of the study .
this research project was approved by the local ethics committee of shiraz university of medical sciences and written informed consents were obtained from all the participants . in addition , the control group was provided with the results after completion of the study .
most of the subjects ( 67.2% ) were between 30 and 40 years old . besides , the age of marriage in 44% and 4% of the subjects were below 20 and above 30 years old , respectively .
in addition , the mean length of marriage was 21.59 4.61 years . moreover , most of the participants ( 43.2% ) had academic degrees and 33.6% had high school and diploma degrees .
the results revealed no significant difference among the three groups regarding tsh ( p=0.448 ) and prolactin levels ( p=0.179 ) before the intervention .
also , no significant difference was found among the three groups concerning orgasmic disorder before the intervention ( p=0.23 ) .
however , a significant difference was observed among e. angustifolia , sildenafil citrate , and control groups in this regard after the intervention ( p=0.004 ) ( table 1 ) .
comparison of frequency of sexual dysfunction ( orgasm disorders ) before and after intervention between the intervention and control groups according to the results of mcnemar test , no significant difference was found in the control group before and after the intervention ( 57.1% vs. 50% ; p>0.05 ) .
also , no significant difference was observed in e. angustifolia group before and after the intervention ( 41.5% vs. 29.3% ; p=0.267 ) . on the other hand ,
a significant difference was found in the sildenafil citrate group before and after the intervention ( 40.5% vs. 29.3% ; p=0.006 ) ( table 1 ) .
overall , e. angustifolia , sildenafil citrate , and control groups respectively showed 29.41% , 58.82% , and 12.5% reduction of sexual dysfunction score as compared to the condition before the intervention .
the findings of the current study indicated a significant difference between the ea group and the control group ( p=0.001 ) and between the sildenafil citrate group and the control group ( p<0.001 ) regarding the mean score of orgasm ( table 2 ) .
comparison of average score of sexual function ( in orgasm and sexual satisfaction area ) before and after intervention between the tests and control groups the study results revealed no significant difference among the three groups concerning sexual satisfaction before the intervention ( p=0.356 ) .
however , a significant difference was observed among the three groups in this regard after the intervention ( p=0.03 ) ( table 3 ) . according to the results of mcnemar test
, a significant difference was observed in e. angustifolia group before and after the intervention ( p<0.001 ) . on the other hand ,
no significant difference was found in the sildenafil citrate group before and after the intervention ( p=0.06 ) .
comparison of frequency of sexual dysfunction ( sexual satisfaction area ) before and after intervention between the intervention and control groups overall , e. angustifolia and sildenafil citrate groups respectively showed 57.14% and 46.66% reduction sexual dysfunction score as compared to the condition before the intervention .
also , a significant difference was observed between the ea group and the control group ( p<0.001 ) and between the sildenafil citrate and control groups ( p<0.001 ) regarding the mean score of sexual satisfaction ( table 2 ) .
in this study , ea , sildenafil citrate , and control groups respectively showed 29.41% , 58.82% , and 12.5% reduction sexual dysfunction score as compared to the condition before the intervention .
this difference was statistically significant in the sildenafil citrate group ( p=0.006 ) , but not in e. angustifolia group ( p=0.267 ) .
nonetheless , a significant difference was observed between the two intervention groups and the control group regarding the mean score of orgasmic disorder ( p<0.001 ) .
caroso ( 2002 ) performed a study on 68 women between 19 and 38 years old who had no symptoms of sexual dysfunction in order to assess the effectiveness of sildenafil citrate .
the participants had to consume sildenafil citrate and placebo for 4 weeks and were entered into the study based on personal experiences questionnaire ( peq ) .
the study results showed that sildenafil citrate improved arousal ( p<0.01 ) , orgasm ( p<0.001 ) and sexual satisfaction ( p<0.001 ) compared to the placebo group ( 22 ) .
2008 ) carried out a research on 22 menopausal women who suffered from orgasmic disorder .
the participants received either 50 mg sildenafil citrate ( 11 subjects ) or placebo ( 11 subjects ) in a single dose for 15 days .
the results revealed a considerable increase in the vaginal blood flow in the sildenafil citrate group as compared to the placebo group ( p<0.05 ) ( 18 ) .
2004 ) investigated the effectiveness of sildenafil citrate in treatment of the women suffering from sexual dysfunction due to multiple sclerosis ( ms ) .
the study was conducted on 19 women with both sexual dysfunction and ms and the results showed that sildenafil citrate did not improve their sexual dysfunction ( p>0.441 ) ( 54 ) . similarly ,
( 55 ) reported that sildenafil citrate had no positive effects on women 's sexual disability score , which is in contrast to the findings of the current study .
sildenafil citrate is among the pde5 inhibitors which by preventing cyclic guanosin monophosphate ( cgmp ) catabolism , leads to an increase in nitric oxide ( no ) production , stimulation of no release and increase in vaginal blood flow .
this , in turn , results in an increase in sexual desire , orgasm , tissue hyperpolarization and relaxation , increase in blood flow , hyperemia and swelling ( 12 ) , eventually leading to improvement of sexual dysfunction . up to now , no specific clinical scales have been used for diagnosis of female sexual dysfunction and no medications have been confirmed for its treatment .
yet , two strategies , i.e. , androgens and pde5 inhibitors , are utilized for reduction of sexual disorders in women ( 56 ) . in the present study ,
e. angustifolia extract decreased the sexual dysfunction score as compared to the condition before the intervention and the control group ; however , the differences were not statistically significant . to date , no studies have been conducted on the effectiveness of e. angustifolia flower in sexual disorders .
therefore , the study results were compared with those of the studies performed on other herbal medications used for sexual disorders .
waynberg and brewer ( 2000 ) aimed to find an alternative for chemical medications used for treatment of female sexual dysfunction and consequently , assessed muira puama and ginkgo in 202 healthy women with low sexual desire . in that study , different aspects of the participants sexual life were investigated before and one month after the treatment . after consuming the supplements , the self - assessment questionnaire scores were higher than average in 65% of the participants .
in addition , the results indicated a significant improvement in the frequency of sexual desires and fantasies , satisfaction with sexual life , intensity of sexual desires , ability to reach orgasm and intensity of orgasm ( p<0.001 ) ( 57 ) .
similarly , ito ( 2006 ) reported that arginmax ( an herbal supplement ) improved sexual dysfunction particularly regarding sexual desire ( 51% vs. 8% in the placebo group ; p=0.008 ) ( 58 ) .
e. angustifolia plant contains significant amount of flavonoids , terpenoids and sitosterol ( 5962 ) .
research has shown that certain flavonoids and sitosterol have analgesic and anti - inflammatory effects ( 62 ) and lead to vascular smooth muscle relaxation ( 63 ) .
evidence has shown that no , as an endogenous vascular dilator , plays a critical role in regulation of vascular tone ( 64 , 65 ) and is the main stimulant of cgmp production in smooth muscles ( 66 ) .
increase in cgmp leads to an increase in the activity of kinase g protein which leads to vascular relaxation by phosphorylation of different molecules ( 67 ) .
on the other hand , some experts believe that increase of cgmp results in smooth muscle vascular relaxation through other mechanisms ( 68 ) .
for instance , cgmp may lead to relaxation of smooth muscles by decreasing the intracellular calcium concentration ( 69 ) .
the positive effect of e. angustifolia on sexual dysfunction and sexual satisfaction in this study may be justified by the aforementioned mechanisms .
the findings of the present study indicated a significant difference between the two intervention groups and the control group concerning the mean score of sexual satisfaction ( p<0.001 ) .
other studies have also found a significant relationship between improvement of sexual performance and sexual satisfaction ( 15 , 57 ) .
research has indicated that improvement of the quality of sexual relationships between husband and wife led to great satisfaction .
it is , therefore , a decisive factor for marital and sexual satisfaction ( 2 , 7071 ) .
overall , it seems that identification and treatment of sexual dysfunctions can increase satisfaction and thus can improve the families strength and survival and the community 's health . according to the previous studies , herbal medications , such as arginmax , ginseng , ginkgo biloba , and ethanol extract ( 7273 ) improved sexual dysfunction through an increase in no production .
sexual dysfunction in women is a serious , complex , multi - factorial problem which might result from biological , psychological , cultural , social and hormonal factors .
since the participants had normal menstrual cycles , hormones , and endocrine parameters , their sexual dysfunction might have occurred due to other factors , including insufficient stimulation and lack of preparation .
phosphodiesterase - type 5 inhibitors ( sildenafil citrate ) and e. angustifolia flower also enhance vaginal smooth muscles relaxation , artery vasodilatation and swelling in the genital system , thereby improving sexual function .
other factors associated with sexual dysfunction include relational problems , lifestyle , and type of food regimen that were not investigated in the current study .
in this study , e. angustifolia , sildenafil citrate , and control groups respectively showed 29.41% , 58.82% and 12.5% reduction of changes as compared to the condition before the intervention .
thus , it seems that sildenafil citrate has been more effective in improvement of sexual dysfunction as compared to e. angustifolia .
the findings of the current study can be used for improvement of women 's and families sexual health . yet , further studies are recommended to be conducted using different doses of e.angustifolia at different times .
| backgroundorgasmic disorder can create a feeling of deprivation and failure and provide mental problems , incompatibility and marital discord .
this study aimed to compare the effects of elaeagnus angustifolia flower extract and sildenafil citrate on female orgasmic disorder in women in 2013.methodsin this randomized clinical trial , 125 women between 18 - 40 years old who suffered from orgasmic disorder were divided into three e. angustifolia , sildenafil citrate and control groups .
the data were gathered using female sexual function index and through measurement of tsh and prolactin .
the first intervention group had to consume 4.5 gr e. angustifolia extract in two divided doses for 35 days and the second one had to use 50 mg sildenafil citrate tablets for 4 weeks one hour before their sexual relationship . however , the control group had to consume the placebo .
the data were analyzed using paired t - test , one - way anova , and bonferroni posthoc test and p<0.05 was considered significant.resultsthe frequency of orgasmic disorder before the intervention was 41.5% , 40.5% , and 57.1% in e. angustifolia , sildenafil citrate , and control groups , respectively ( p=0.23 ) .
however , these measures were respectively 29.3% , 16.7% , and 50% after the intervention ( p=0.004 ) . a significant difference between the two groups regarding sexual satisfaction after the intervention ( p=0.003 ) compared to the beginning of the study ( p=0.356 ) .
besides , the highest reduction of changes after the intervention ( 58.82% ) was observed in the sildenafil citrate group.conclusionboth e. angustifolia extract and sildenafil citrate were effective in reduction of the frequency of orgasmic disorder in women . |
we measured emission lines for @xmath3 spectra in the stromlo - apm ( sapm ) redshift survey of galaxies with @xmath4 mag , covering 4300 square degrees of the southern sky .
galaxies are at @xmath5 , and @xmath6 ( loveday et al . 1996 ) .
these galaxies have been selected randomly at a rate of 1 in 20 from automated plate measurements ( apm ) scans ( maddox et al . 1990 ) .
spectra were obtained using the dual beam spectrograph equipped with 4 ccds on the anu 2.3 m telescope .
the wavelength coverage is 3700@xmath75000 in the blue , and 6300@xmath77600 in the red .
the dispersion is typically 1 per pixel , and using a slit of width 8 the spectral resolution is 5 .
we checked that our equivalent widths ( ew ) are not dependent on the area of each galaxy covered by the slit , which is @xmath8% on average .
consequently , our results are comparable to integrated spectra of nearby galaxies , or to distant galaxies ( tresse et al . 1998 ) .
we find that 62% of galaxies are h@xmath2 emission - line galaxies ( elg ) with @xmath9 .
the remaining are classified as absorption - line galaxies ( alg ) .
the sample is divided into equal numbers of elg and alg at @xmath10 .
ew are not corrected for stellar absorption .
when comparing surveys , percentages of elgs have to be taken with extreme care , since the spectral resolution , the aperture , the magnitude limit , the passband selection , etc . lead to very different percentages .
the fraction of elg depends strongly on the absolute magnitudes , m(@xmath0 ) , and the size of galaxies ( figure 1 ) . from @xmath11 to @xmath12 mag , or from size
10,000 to 100 kpc@xmath13 , it increases by a factor of @xmath14 or 4 , respectively .
elg are more common than alg in intrinsically faint galaxies , and small systems .
this agrees with the general picture where dwarves ( faint and small ) are more actively forming stars , than their bright counterparts in the local universe .
this is a reflection of the difference between elg and alg luminosity functions ( loveday et al .
it is also consistent with the `` peak '' of sfr observed at @xmath15 , since the overall luminosity density is dominated by bright galaxies , which formed most of their stars much earlier than dwarves , which are actively forming stars today .
the mean and the median ew(h@xmath2 ) ( @xmath16 ) are respectively 19 and 15 in the sapm .
the h@xmath2 line has the advantage that it is directly correlated to the `` instantaneous '' star formation rate ( sfr ) , or the time scale since the last burst . whereas [ o ii]@xmath173727 line depends on the metallicity of the galaxy , and on the hardness of the global ionizing spectrum .
ew(h@xmath2 ) is the ratio of the flux originating from massive , young stars ( ob type ) in h ii regions , over the flux from the old stellar population emitting in the rest - frame @xmath18 passband , which forms the continuum at h@xmath2 . in figure 2
, we show that the fraction of faint elg ( @xmath19 ) increases as a function of ew . from @xmath20 to @xmath21 ( which corresponds to a sfr increasing by a factor @xmath22 5 ) , the fraction increases by a factor @xmath23 .
another way to look at this is to consider the fraction of high ew elg ( @xmath24 ) , which increases at fainter m(b@xmath25 ) .
since b magnitudes are correlated with h@xmath2 luminosities , the fainter a galaxy , the smaller its h@xmath2 luminosity is ( tresse & maddox 1998 , and also these proceedings ) .
so , faint galaxies with high ew(h@xmath2 ) , means they are blue galaxies .
this corresponds also to the strong correlation between colors and ew(h@xmath2+[n ii ] ) ( kennicutt & kent 1983 ) .
they have a young stellar population , so blue colors , high h@xmath2 fluxes , and less old stars .
massive , large galaxies , or bright galaxies do not have the strongest ew(h@xmath2 ) .
the fraction of young stars to old stars is smaller than for faint galaxies , leading to a red continuum , and smaller ew on average .
so they are older systems , and less numerous but they are still contributing to most of the luminosity density in deep surveys .
it is now well established that the faint end of the luminosity function of @xmath26-selected surveys is dominated by actively star - forming galaxies .
this is what we find also in the sapm ( loveday et al .
1998 , @xmath27 and @xmath28 for @xmath29 and 19 ) .
we note that the overall sapm luminosity function at @xmath30 has a shallower slope than the one from the preliminary 2df data ( @xmath31 ) , which were selected from the same parent catalog as the sapm ( see maddox , these proceedings ) .
the correlation between ew(h@xmath2 ) and ew([o ii ] ) has been established by kennicutt 1992 ( k92 ) , using a selection of galaxies covering all spectral types .
however , k92 s selection is not a truly representative statistical sample of the local universe , unlike our sample . in figure 3 , we find @xmath32 ) = 0.68\ ew(h\alpha)$ ] ( k92 : 0.61 ) , @xmath32 ) = 0.47\ ew(h\alpha + [ n~ii])$ ] ( k92 : 0.40 ) .
this is consistent with k92 s result given the large scatter observed in both samples .
our scatter is not due to poor signal - to - noise , but reflects certainly different stellar , dust and metal contents sampled .
we emphasize that ew measured from the overall galaxy content are likely to be affected by dust . indeed , recombination emission lines originate from dusty h ii regions , where hot stars ( ob type ) are formed , whereas the continuum at [ o ii ] or h@xmath2 comes from long - lived stars sitting in less , or non obscured regions .
ew([o ii ] ) is more affected by the dust than ew(h@xmath2 ) .
hence , the absolute ew relation should be in average slightly higher .
kennicutt , r.c . ,
kent , s.m .
1983 , , 88 , 1094 kennicutt , r.c .
1992 , , 388 , 310 ( k92 ) loveday , j. , peterson , b.a . , maddox , s.j . , and efstathiou , g. , 1996 , apjs , 107 , 201 loveday , j. , tresse , l. , maddox , s.j
. 1998 in preparation maddox , s.j . ,
sutherland , w.j . ,
efstathiou , g. , loveday , j. 1990 , , 243 , 692 tresse , l. , maddox , s.j .
, loveday , j. 1998 in preparation tresse , l. , maddox , s.j .
1998 , , 495 , march 10 issue ( astro - ph/9709240 ) tresse , l. , rola , c. , hammer , f. , stasiska , g. , le fvre , o. , lilly , s.j . ,
crampton , d. 1996 , 281 , 847 | we analyse emission - line properties of the @xmath0-selected stromlo - apm spectra ( @xmath1 ) .
because this is a representative sample , we can study the global spectral properties of the local galaxy population .
we classify spectra according to their h@xmath2 emission , which is closely related to massive star formation .
this study gives a comparative local point for analysis of more distant surveys .
we show that in the local universe , faint , small galaxies are dominated by star formation activity , while bright , large galaxies are more quiescent .
obviously this picture of the local universe is quite different from the distant one , where bright galaxies appear to show a rapidly - increasing activity back in time . #
1to 0pt#1 # 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in |
it is now known that hepcidin plays an important role on intestinal iron absorption and iron recycling in macrophages .
hepcidin functions by decreasing the amount of iron released from macrophages or absorbed from intestine .
it is also known that hepcidin defiency may lead to severe iron overload in multiple organs .
two important transmembrane proteins , hfe ( histocompatibility complex class i - like transmembrane protein ) and hjv ( hemojuvelin ) , are key modulators of hepcidin expression .
hjv acts as a bone - morphogenetic protein ( bmp ) co - repressor , driving hepcidin transcription via the bmp - smad signaling cascade .
using a mouse model , kent et al showed that hfe and hjv operate in the same pathway for regulation of hepcidin expression and iron metabolism .
recently , wu et al showed that hjv is the key regulator of hepcidin and that hfe acts in an hjv - dependent manner .
some mutations in these 2 proteins have been associated with severe iron overload in patients with hereditary haemochromatosis .
dysregulation in iron homeostasis may also lead to mild iron overload , which has not been generally taken into account .
two previous gwas studies have found an association between hfe ( h63d ) genetic variant and hypertension .
we were able to replicate this association in the tamrisk cohort and showed that carriers of the mutation had higher risk for hypertension than those without this mutation .
mutations in the hjv gene that lead to severe iron overload are rare , although over 40 mutations of hjv have been recognized .
therefore , we analyzed 2 relatively frequent variants of this gene that have been shown to mediate dysfunctional iron regulation . in the present study , we wanted to examine a possible association between these hjv genetic variants and hypertension in the finnish tamrisk cohort .
the tampere adult population cardiovascular risk study ( tamrisk ) is a prospective , longitudinal population - based health survey study in tampere , a city in southern finland with a population of 210 000 .
the data for the tamrisk study was collected from the periodic health examinations ( phe ) done for 50-year - old men and women living in tampere .
the phe included one 60-minute session with a public health nurse at the center 's health examination unit as previously described .
tamrisk data includes information of risk factors for hypertension : blood pressure , weight , family history of cardiovascular diseases , lipid values and smoking , diabetes , and exercise habits .
physical activity was defined as times of exercise / week ( enhanced breathing and sweating ) .
current and previous diseases were identified based on self - report of diagnosis by a physician , including hypertension .
cases in this study were the subjects who had hypertension and/or cad at the age of 50 years as diagnosed by a physician by normal healthcare procedures .
for most patients , physicians diagnose hypertension when blood pressure readings are consistently 140/90 mm hg or above . for each case , at least 1 normotensive control with the same sex and similar smoking habits were chosen from a phe cohort ( n = 6000 ) .
smoking status was evaluated based on self - reporting . using the patient 's national identity code ,
data on hospitalizations including icd-10 codes for discharge diagnoses were obtained from the finnish national hospital discharge registry ( hilmo ) maintained by the national institute of health and welfare .
prevalence of ischemic heart diseases ( i20-i25 ) were followed up from 2005 to 2014 until the subjects were on the average 60 years old .
buccal swabs for dna extraction and a permissions form to use phe data were collected by mail separately of the physical examination .
the ethics committees of the tampere university hospital and the city of tampere approved the study .
genotyping was performed using kasp ( competitive allelic specific amplification ) genotyping services at kbioscience institute , uk . details of this method can be obtained from https://www.lgcgroup.com / genotyping/. statistical analyses were performed using ibm spss statistics 23 , and hardy weinberg equilibrium of the genotypes was calculated using oege ( online encyclopedia calculator for genetic epidemiology studies ) .
t - test and 1-way anova for continuous variables ( clinical characteristics ) and chi - square test for categorical variables ( hypertension , coronary artery disease ) were applied for the comparison of hjv genotype groups .
associations of the genotyped hjv gene variants with hypertension / coronary artery disease with risk factors ( bmi , glucose , cholesterol and gender ) were analyzed using logistic regression analysis .
the tampere adult population cardiovascular risk study ( tamrisk ) is a prospective , longitudinal population - based health survey study in tampere , a city in southern finland with a population of 210 000 .
the data for the tamrisk study was collected from the periodic health examinations ( phe ) done for 50-year - old men and women living in tampere .
the phe included one 60-minute session with a public health nurse at the center 's health examination unit as previously described .
tamrisk data includes information of risk factors for hypertension : blood pressure , weight , family history of cardiovascular diseases , lipid values and smoking , diabetes , and exercise habits .
physical activity was defined as times of exercise / week ( enhanced breathing and sweating ) .
current and previous diseases were identified based on self - report of diagnosis by a physician , including hypertension .
cases in this study were the subjects who had hypertension and/or cad at the age of 50 years as diagnosed by a physician by normal healthcare procedures .
for most patients , physicians diagnose hypertension when blood pressure readings are consistently 140/90 mm hg or above . for each case , at least 1 normotensive control with the same sex and similar smoking habits were chosen from a phe cohort ( n = 6000 ) .
smoking status was evaluated based on self - reporting . using the patient 's national identity code ,
data on hospitalizations including icd-10 codes for discharge diagnoses were obtained from the finnish national hospital discharge registry ( hilmo ) maintained by the national institute of health and welfare .
prevalence of ischemic heart diseases ( i20-i25 ) were followed up from 2005 to 2014 until the subjects were on the average 60 years old .
buccal swabs for dna extraction and a permissions form to use phe data were collected by mail separately of the physical examination .
the ethics committees of the tampere university hospital and the city of tampere approved the study .
dna was extracted from buccal swabs using a commercial kit ( qiagen inc . , valencia , ca ) .
genotyping was performed using kasp ( competitive allelic specific amplification ) genotyping services at kbioscience institute , uk . details of this method can be obtained from https://www.lgcgroup.com / genotyping/.
statistical analyses were performed using ibm spss statistics 23 , and hardy weinberg equilibrium of the genotypes was calculated using oege ( online encyclopedia calculator for genetic epidemiology studies ) .
t - test and 1-way anova for continuous variables ( clinical characteristics ) and chi - square test for categorical variables ( hypertension , coronary artery disease ) were applied for the comparison of hjv genotype groups .
associations of the genotyped hjv gene variants with hypertension / coronary artery disease with risk factors ( bmi , glucose , cholesterol and gender ) were analyzed using logistic regression analysis .
clinical characteristics of the study population at the age of 50 years are presented in table 1 .
briefly , the case group comprised 336 hypertensive cases and control group 480 normotensive subjects with the same sex distribution and similar smoking habits .
a total of 78 subjects were found to have coronary artery disease when followed up to 60 years of age .
clinical characteristics of cases and controls of the study population and subpopulation with bmi < 30 .
genotyping was successful in 808 subjects for the hjv rs16827043 ( a > g ) and in 795 subjects for the rs7536827 ( a > t ) .
the measured genotype frequencies were not significantly different from the expectations of hardy weinberg equilibrium ( = 0.22 for rs16827043 and = 0.09 for rs7536827 ) .
clinical characteristics of the study population stratified according to hjv rs 7536827 genotypes . for hjv
polymorphism rs16827043 , there were only 3 individuals who were homozygous for the gg genotype and they were combined to the ga genotype group . at the age of 50 years , 58 of 111 g - allele carriers ( 52,2% ) had diagnosed hypertension compared to 287 of 697 ( 41.3% ) of those homozygous for the wild type ( aa ) , respectively ( p = 0.041 ) . also , diastolic blood pressure readings were significantly higher among g - allele carriers ( table 2 ) .
when the risk for hypertension was analyzed by logistic regression using hjv variants , bmi , glucose , cholesterol , and gender as explainable variables , or for hjv g - allele carriers was 1.66 ( p = 0.03 , 95% ci : 1.062.60 ) , for bmi 1.19 ( p < 0.001 , 95% ci : 1.151.24 ) , for glucose 1.49 ( p < 0.001 , 95% ci : 1.161.92 ) , for cholesterol 0.99 ( p = 0.96 , 95% ci : 0.841.18 ) , and for gender 1.50 ( p = 0.02 , 95% ci : 1.072.09 ) compared with aa genotype . in order to exclude the strong effect of bmi on hypertension
, we also analyzed a subpopulation of the study participants with normal or only slightly elevated bmi .
when overweight participants ( bmi > 30 ) were excluded from the analyses , the risk for hypertension among g - allele carriers remained significant ( or = 1.80 , 95% ci 1.092.98 , p = 0.02 ) . adjusted and unadjusted results are in table 4 .
unadjusted and adjusted or results obtained from logistic regression analysis for hypertension . for the other polymorphic site ( rs7536927 , t > a ) , no association between genotypes or combined alleles and hypertension was found in the whole study population ( p = 0.29 for genotypes and p = 0.24 for a - allele carriers ) . however , when subjects were stratified according to weight , carriers of the a - allele whose bmi was less than 30 had more often hypertension compared with those homozygous for the wild type ( tt ) ( or = 1.56 , p = 0.04 , 95% ci 1.012.39 ) ( table 4 . ) as with the rs7536827 , no association with coronary artery disease was found ( table 2 ) .
the results of the present study suggest that genetic variation in the hjv gene is significantly associated with hypertension in a 50-year - old finnish population .
previous studies of the hjv and hfe genetic polymorphisms have concentrated mainly on hemochromatosis . our results and those of others indicate that disturbances in iron metabolism may also increase the risk for hypertension .
we found no impact of the 2 studied hjv polymorphisms on coronary artery disease . in this paper , we show that the minor allele g of the hjv variant rs16827043 was associated with hypertension .
in addition , the association between the minor allele and hypertension was even stronger among normal- or only slightly overweight subjects . for the other hjv polymorphic site rs7536827 , no statistically significant association with hypertension was found .
however , when t allele carriers were combined and obese subjects were excluded , also this genetic variation associated with hypertension . although the mechanism is not known , our result together with previous ones provides a further link between iron metabolism and hypertension .
mild iron overload is one possible explanation for higher blood pressure of carriers of the hjv minor variants , as has been suggested for h63d .
a recent study has reported that hjv functions as enhancer for iron signaling to hepcidin . since hepcidin is the main iron regulatory hormone , disturbances in pathways affecting hepcidin expression may block its function as a feedback inhibitor of iron absorption .
however , only complete loss of hepcidin in humans is responsible for rare yet severe forms of massive body iron overload . in finland ,
tests for assessing body iron levels ( serum ferritin and transferrin saturation ) are not routinely measured and therefore a limitation of the tamrisk study population is the lack of these saturation markers .
however , it has previously been published that men with essential hypertension had greater iron stores than normotensive controls .
it is known that prevalence of hypertension is higher in obese than in lean populations and there is nearly linear relationship between bmi and blood pressure .
it has previously been shown that there is a gene - environmental association between hypertension genes and bmi .
the association of hjv and hypertension was similar or even stronger for normal weight and slightly overweight subjects than in obese subjects , confirming the role of hjv .
although the mechanism is not yet known , our results suggest that the minor allele g of the hjv variant ( rs16827043 ) is associated with higher risk for hypertension at the age of 50 years , compared with the aa - genotype carriers .
in addition , we found that among normal or slightly overweight individuals , also t - allele of the hjv rs7536827 increases the risk for hypertension .
it is therefore possible that dysregulation in iron metabolism is a significant factor behind hypertension . | abstractit is known that iron overload may lead to an increased risk for many diseases . according to gwas studies , iron regulatory protein hfe gene variant h63d ( rs1799945 )
was associated with hypertension , an observation which we were able to confirm also in our tamrisk cohort .
thus , it is possible that abnormalities in iron homeostasis may predispose to hypertension .
this prompted us to study whether there is an association between hypertension and another iron overload - associated gene , hemojuvelin ( hjv ) , which has 2 common polymorphic sites ( rs 16827043 , rs7536827).the study included 336 hypertensive cases and 480 controls .
all participants were 50- year - old finnish men and women , and the data was collected from the tampere adult population cardiovascular risk study ( tamrisk ) .
genotypes were determined using competitive allelic specific pcr ( kasp).we found that the minor variant of the hjv polymorphic site rs16827043 ( g - allele ) is a statistically significant factor associated with hypertension among 50 year - old individuals compared with the aa genotype carriers ( or = 1.66 , 95% ci : 1.06 2.60 , p = 0.03 ) .
the risk was even higher when overweight subjects ( bmi>30 ) were excluded from the analyses .
for the other polymorphic variant rs7536827 , association with hypertension was found only among normal or slightly overweight a - allele carriers.in conclusion , hjv genetic variants were associated with essential hypertension in finnish subjects from the tamrisk cohort .
previous studies together with the present one indicate that individuals with possible dysregulation of iron metabolism may have higher risk for hypertension than those with normal iron homeostasis . |
SECTION 1. SHORT TITLE AND TABLE OF CONTENTS.
(a) Short Title.--This Act may be cited as the ``Animal Welfare Act
Amendments of 1997''.
(b) Table of Contents.--The table of contents of this Act is as
follows:
Sec. 1. Short title and table of contents.
Sec. 2. Expanded definition of dealer.
Sec. 3. Licensing requirements.
Sec. 4. Prohibited activities without license.
Sec. 5. Provisions regarding auction sales.
Sec. 6. Enforcement and penalties.
Sec. 7. Injunction authority.
SEC. 2. EXPANDED DEFINITION OF DEALER.
(a) Dealer.--Subsection (f) of section 2 of the Animal Welfare Act
(7 U.S.C. 2132) is amended to read as follows:
``(f) Dealer.--(1) The term `dealer' means any person who (in
commerce for compensation or profit) acquires, delivers for
transportation or transports (except as a carrier), buys or offers to
buy, sells or offers for sale, leases or offers to lease, negotiates
the purchase, sale, or lease of, or otherwise transfers--
``(A) any animal, whether alive or dead, for research,
experimentation, teaching, exhibition, or use as a pet;
``(B) any dog for hunting or security purposes; or
``(C) any dog or cat for breeding purposes.
``(2) The term includes an operator of an auction sale at which any
activity described in paragraph (1) takes place and any person who owns
or leases premises that are used for a trade day, flea market, or
similar event at which any activity described in paragraph (1) takes
place.
``(3) The term includes an animal pound or shelter operated by or
on behalf of a local government and any governmental entity that sells
or otherwise provides animals to any dealer or research facility.''.
(b) Clerical Amendments.--Section 2 of such Act is further
amended--
(1) by striking the semicolon at the end of subsections
(a), (b), (d), (e), and (g) through (k) and inserting a period;
and
(2) in subsection (n), by striking ``; and'' and inserting
a period.
SEC. 3. LICENSING REQUIREMENTS.
Section 3 of the Animal Welfare Act (7 U.S.C. 2133) is amended to
read as follows:
``SEC. 3. LICENSING REQUIREMENTS.
``(a) Issuance of Licenses.--To apply for a license under this
section, a dealer or exhibitor shall submit to the Secretary an
application in such form and manner as the Secretary may prescribe. The
Secretary shall issue licenses to dealers and exhibitors upon payment
of the applicable fee established pursuant to section 23 and
demonstration by the dealer or exhibitor of compliance with the
regulations and standards promulgated by the Secretary pursuant to this
Act.
``(b) Licensing Exemptions.--
``(1) Exemptions authorized.--The Secretary may issue
regulations exempting persons described in paragraph (2) from
licensing and other requirements under this Act, subject to
such conditions as the Secretary may prescribe, if, in the
judgment of the Secretary--
``(A) the licensing of such persons would not
effectuate the policy of the Act; and
``(B) the activity of the persons does not involve
the use of animals for research purposes.
``(2) Persons eligible for exemptions.--Persons who may be
exempted from licensing and other requirements under paragraph
(1) include the following:
``(A) Operators of retail pet stores (except retail
pet stores which sell animals to research facilities,
exhibitors, or dealers).
``(B) Persons who sell wild or exotic animals, as
defined by the Secretary, with respect to such wild or
exotic animals.
``(C) Persons whose business activities as dealers
or exhibitors are de minimis.''.
``(c) Licenses Prohibited.--The Secretary shall not issue (or
renew) a license under this section with regard to any of the following
persons:
``(1) A person whose license has been suspended, revoked,
or voluntarily terminated while the person was in violation of
this Act or a regulation or standard promulgated under this
Act.
``(2) A person who has not paid any civil penalty
previously assessed by the Secretary under this Act.
``(3) A person who has been convicted of, or entered a plea
of nolo contendere or its equivalent to, a charge of violating
any of the following:
``(A) A treaty or Federal, State, or local law
involving the care or treatment of, or recordkeeping
for, animals.
``(B) The Marine Mammal Protection Act of 1972 (16
U.S.C. 1361 et seq.), the Endangered Species Act of
1973 (16 U.S.C. 1531 et seq.), or any treaty, Federal,
State, or local law for the protection of endangered or
threatened species.''.
SEC. 4. PROHIBITED ACTIVITIES WITHOUT LICENSE.
Section 4 of the Animal Welfare Act (7 U.S.C. 2134) is amended to
read as follows:
``SEC. 4. EFFECT OF FAILURE TO OBTAIN LICENSE OR EXEMPTION.
``(a) Treatment of Licensed and Exempted Persons.--Subsection (b)
does not apply to a dealer or exhibitor who--
``(1) holds a current and unsuspended license from the
Secretary under section 3(a); or
``(2) is exempted by the Secretary from such licensing
requirement pursuant to section 3(b).
``(b) Prohibition Against Certain Activities.--Except in the case
of dealers and exhibitors described in subsection (a), a dealer or
exhibitor may not--
``(1) acquire any animal;
``(2) sell or offer for sale any animal;
``(3) lease or offer for lease any animal;
``(4) transport or offer for transportation any animal;
``(5) buy or offer to buy any animal;
``(6) exhibit or offer to exhibit;
``(7) transfer any animal; or
``(8) engage in any other business activity as a dealer or
exhibitor.''.
SEC. 5. PROVISIONS REGARDING AUCTION SALES.
(a) Regulation.--Section 12 of the Animal Welfare Act (7 U.S.C.
2142) is amended to read as follows:
``SEC. 12. HUMANE STANDARDS AND RECORDKEEPING REQUIREMENTS AT AUCTION
SALES.
``The Secretary shall promulgate humane standards and recordkeeping
and reporting requirements to govern the purchase, sale, or handling of
animals by--
``(1) dealers, research facilities, exhibitors at auction
sales; and
``(2) by persons consigning animals to auction sales.''.
(b) Conforming Amendments.--
(1) Holding period.--Section 5 of the Animal Welfare Act (7
U.S.C. 2135) is amended by striking ``Secretary: Provided, That
operators of auction sales subject to section 12 of this Act''
and inserting ``Secretary, except that operators of auction
sales''.
(2) Research facility purchases.--Section 7 of the Animal
Welfare Act (7 U.S.C. 2137) is amended by striking ``subject to
section 12 of this Act''.
(3) Federal purchases.--Section 8 of the Animal Welfare Act
(7 U.S.C. 2138) is amended by striking ``subject to section 12
of this Act''.
(4) Agency relationship.--Section 9 of the Animal Welfare
Act (7 U.S.C. 2139) is amended by striking ``subject to section
12 of this Act''.
(5) Enforcement and penalties.--Section 19 of the Animal
Welfare Act (7 U.S.C. 2149) is amended--
(A) in subsections (b) and (c), by striking
``carrier, or operator of an auction sale subject to
section 12 of this Act,'' both places it appears and
inserting ``or carrier''; and
(B) in subsection (d), by striking ``, exhibitor,
or operator of an auction sale subject to section 12 of
this Act,'' and inserting ``or exhibitor''.
SEC. 6. ENFORCEMENT AND PENALTIES.
Subsection (a) of section 19 of the Animal Welfare Act (7 U.S.C.
2149), is amended to read as follows:
``(a) Suspension or Refusal To Renew License.--
``(1) Temporary and final orders.--If the Secretary has
reason to believe that a person licensed under this Act has
violated or is violating any provision of this Act (or the
regulations or standards issued under this Act), the Secretary
may suspend or refuse to renew the person's license
temporarily, but not to exceed 120 days except as provided in
paragraph (3). If after notice and opportunity for hearing the
violation is determined to have occurred, the Secretary may
suspend or refuse to renew the person's license for such
additional period as the Secretary may specify or revoke the
license. An order suspending, revoking, or refusing to renew a
license after notice and opportunity for hearing shall be
effective pending the final determination of the Secretary.
``(2) Notice of temporary action; licensee rights.--When
the Secretary temporarily suspends or refuses to renew a
license under paragraph (1), the Secretary shall promptly send
written notice to the licensee informing the licensee of the
following:
``(A) The nature of the alleged violation.
``(B) The time and place of the alleged violation.
``(C) The action of the Secretary in response to
the alleged violation.
``(D) The right of the licensee to request a
hearing on the matter only during the 10-day period
beginning on the date the licensee receives the written
notice.
``(3) Time for hearing.--A hearing on an alleged violation
shall be held within 30 days after the date on which the
Secretary receives the request for the hearing. However, unless
the licensee requests the hearing within 10 days of receipt of
the written notice, the licensee shall forfeit any right to a
hearing within such 30-day period, and the suspension or
refusal to renew shall remain in effect until a hearing is held
and the administrative law judge issues a decision and order.
``(4) Time for decision.--The administrative law judge
shall issue a decision and order within 30 days after the
conclusion of a hearing whenever a suspension or refusal to
renew is in effect.''.
SEC. 7. INJUNCTION AUTHORITY.
Subsection (a) of section 29 of the Animal Welfare Act (7 U.S.C.
2159) is amended to read as follows:
``(a) Request for Attorney General To Apply for Injunction.--
``(1) Request.--Whenever the Secretary has reason to
believe that a person described in paragraph (2) should be
enjoined from operating in violation of this Act or the
regulations and standards issued under this Act, the Secretary
shall notify the Attorney General. Upon notification, the
Attorney General may apply to the United States district court
for the district in which the person resides or conducts
business for a temporary restraining order or preliminary
injunction to prevent the person from operating in violation of
this Act or the regulations and standards prescribed under this
Act.
``(2) Circumstances for making request.--A person referred
to in paragraph (1) is a dealer, exhibitor, research facility,
carrier, or intermediate handler that the Secretary has reason
to believe--
``(A) is dealing in stolen animals;
``(B) is placing the health of any animal in danger
in violation of this Act or the regulations or
standards issued under this Act; or
``(C) is otherwise in violation of this Act or the
regulations and standards issued under this Act.
``(3) Dealing in animals.--For purposes of paragraph (2), a
person who engages in any of the activities described in
section 2(f)(1) shall be considered to be dealing in
animals.''. | Animal Welfare Act Amendments of 1997 - Amends the Animal Welfare Act to redefine "dealer," including delineation of auction operators and shelters or other facilities operated by or for a governmental entity.
Revises licensing (and exception) provisions. Prohibits license issuance or renewal to a person who: (1) loses a license for a violation of such Act or failure to pay a related civil penalty; or (2) has violated another animal welfare or species protection law or treaty.
Directs the Secretary of Agriculture to promulgate humane standards and recordkeeping requirements for animal auctions.
Sets forth enforcement and injunction provisions. |
some twenty years after gdel gave the first proof of its completeness result ( see @xcite for an english translation of the original paper ) , henkin ( @xcite ) found a substantially different strategy to prove it , giving an alternative approach which has become standard in the exposition of the subject , see for example @xcite .
the latter treatment inspired the present one .
in particular the proof mechanism of [ teosatisfiability ] is unchanged .
+ what has been changed is the derivation of [ propsatisfiability ] , which is the main result ; it is given in a quite different way , attentive to the economy of derivation rules . as a consequence
, it is shown that satisfiability theorem , which is the key for completeness in all the arguments known to author ( gdel s included ) , requires one rule less than completeness .
+ in other words , the rule set large enough to prove any true statement has one rule more than the rule set large enough that it can be enlarged without making any consistent set of formula inconsistent : compare [ propcompletenesswrtconsistency ] with [ theocompleteness ] . +
and anyway , the completeness theorem can inherently be proven according to a set of basic deduction rules ( listed in [ tenrules ] ) which lacks `` proof by cases '' rule , and then cut - rule , which is derived from it ( see @xcite , iv.3.2 ) , right from the start .
+ as a byproduct , this led to a careful reformulation of consistency - related definitions , and to a generalization of the construction of henkin for the model of a given consistent set of formula to the generic free interpretation and quotient construction ( and ) . +
further , a reformulation of first - order logic syntax and semantics in term of semigroups is given in [ sectsyntax ] and [ sectsemantics ] .
a plus of this approach is that definitions and some proofs get shorter and compact , albeit arguably obscuring the intuitive meaning of things , which is what standard treatment is based on . + all these addictional results are relegated to appendix so as not to obscure the main result .
+ for yet alternative proofs of this same cornerstone result , the reader can see @xcite or @xcite .
in sections [ sectsyntax ] and [ sectsemantics ] , syntax and semantics have been formalized . here a formalization of deductive proofing is set up . all along the tractation of completeness theorem , we fix the symbols set @xmath1 and the variable symbols set @xmath2 and explicitly require them both to be at most countable .
let @xmath3 be finite .
rule number @xmath4 rule number @xmath5 rule number @xmath6 rule number @xmath7 rule number @xmath8 rule number @xmath9 rule number @xmath10 rule number @xmath11 rule number @xmath12
rule number @xmath13 the rules given in [ tenrules ] have a role similar to that of construction rules for @xmath14 and @xmath15 seen in [ termsandformulas ] : the former decree which sequents are admitted in proofs , the latter ruled what strings of symbols are accepted to make computations on , and were built with syntactical conformity in mind , so to filter exactly the formulas that other authors call well - formed to emphasize the point . correspondingly , the first requisite one expects from derivation rules is that any formula derived from true assumption must be true as well , i.e. that basic derivation rules are correct . checking that this is indeed the case for our basic rules is straightforward but tedious ;
let us just state a fundamental consequence : [ theoconsistency ] any satisfiable set of formulas is consistent .
formal definition of consistency is to come in [ sectionconsistency ] , anyway this should not pose a problem for some informal motivational discussion . the proof of [ theoconsistency ] is much easier than that of its reverse ( satisfiability theorem , [ teosatisfiability ] ) , which is done below . a first symptom of the trickiness involved : if one looks at [ theoconsistency ] s statement , there s no ambiguity in it , in that the declared consistency holds irrespective of the deduction rules adopted ; one can add or subtract arbitrary deduction rules and , provided they are correct , [ theoconsistency ] stands still . on the other hand ,
if faced with statement `` any consistent set of formulas is satisfiable '' , one may well , and should , ask : `` consistent according to what derivation rules ? '' . + we shall later see , indeed , that every basic rule ( except [ nctrrule ] which is used only for the easy derivation , from [ teosatisfiability ] , of the stronger completeness theorem , [ theocompleteness ] ) is needed along the proof , and this results in having to get fussy about always specifying according to which rules one is deriving .
+ in particular , satisfiability theorem need all - around consistency for its thesis to hold , and is not granted to stand for weaker - consistent sets of formulas , simply because of the inability of finding some proof dispensing one of the basic rules .
so we need a compact way to always specify which rules are assumed at each stage of the work .
the letter @xmath16 will denote the generic subset of the set of basic rules provided in [ tenrules ] .
+ having enumerated each member of the latter permits to bijectively denote each member of its power set with a binary string of digits .
that is , each subset of basic rules can be associated with a natural number less than .
+ for example the rule set @xmath17 can be identified with the number .
+ with a handy notational abuse , one can thus write relations like @xmath18 to compactly state that he is considering a set of rules @xmath16 including at least and
. + finally , @xmath19 will be the set of all the rules derivable given the starting rule set @xmath16 . here
are some derivable rules for our convenience in future arguments .
their derivation is omitted in most cases , being short and easy .
+ if @xmath18 then @xmath19 contains the following rule : @xmath20 if @xmath18 then @xmath19 contains the following rule : @xmath21 if @xmath18 then @xmath19 contains the following rule : @xmath22 if @xmath18 or @xmath23 then @xmath19 contains the following rule : @xmath24 we do the case @xmath18 : the sequent @xmath25 is given , and @xmath26 is introduced by [ assrule ]
apply respectively [ antrule ] and to trigger this derivation : @xmath27 we continue to use @xmath16 to indicate a generic subset of basic rules , and study the scope of derivations when varying which rules we admit in @xmath16 .
[ defexpansion ] the letter @xmath16 shall be overloaded to denote with @xmath28 the logical expansion of @xmath29 according to @xmath16 , that is the set of formulas @xmath30 @xmath29 is said to be @xmath16-expanded iff @xmath31 .
obviously @xmath32 , since derivable rules are just handy placeholders replaceable with a full derivation , similar to the concept of macro in computer science .
the following definitions characterize a set of formulas according to its logical properties , and complete the definitions given in [ sectfamiliesofformulas ] , which pursued the same task in a sheer syntactical manner .
one says that @xmath29 is @xmath16-consistent , and writes @xmath33 , iff @xmath34 has cardinality not exceeding @xmath35 .
equivalently , @xmath28 is not patently inconsistent .
@xmath29 is said to be @xmath16-maximal iff it is a @xmath16-consistent covering .
in making use of above definitions we shall often elide the @xmath16 letters when there is no reasonable ambiguity possible .
[ lemmamaximalcovering ] if @xmath16 includes assumption rule , then 1 .
@xmath29 is maximal @xmath36 is a minimal covering and @xmath29 is expanded .
@xmath29 is maximal @xmath37 3 .
@xmath38 1 .
@xmath39 direction : : : @xmath29 being a covering implies @xmath40 , while it being consistent implies , using assumption rule , that same cardinality being @xmath41 .
+ suppose @xmath42 . by contradiction
, @xmath43 can not be in @xmath29 , for if it were then , by assumption rule , @xmath44 , which would violate consistency .
thus @xmath45 which , minimal covering property having already been ascertained , implies @xmath46 .
@xmath47 direction : : : it all reduces to showing that @xmath29 is consistent : @xmath48 where middle deduction uses minimal covering hypothesis , while external ones both use expansion hypothesis .
no deduction rule was needed , which is remarkable .
2 . assuming lhs of last thesis , consistency and assumption rule give @xmath49 .
so @xmath46 , being the latter a minimal covering .
obvious .
[ consistencyvsimplication ] @xmath18 , @xmath50 and @xmath51
. then 1 .
not @xmath52 2 .
@xmath42 and @xmath53 1 .
there are @xmath54 , @xmath55 finite such that @xmath56 and @xmath57 .
+ this can be restated as @xmath58 and @xmath59 , with @xmath60 ; by [ antrule ] @xmath61 can be made non - empty , so using [ pctrrule ] : @xmath62 yielding @xmath63 , i.e. @xmath64 .
2 . the hypothesis implies @xmath65 which , using previous point , gives @xmath66 .
[ weakconsistency ] if @xmath18 or @xmath23 , then @xmath67 the easy proof is omitted . [ defmaximizationconstructions ] given a set of rules @xmath16 and an enumeration @xmath68 of @xmath14 ( so that @xmath69 , where @xmath70 ) , define , for any @xmath71 : @xmath72 finally , set @xmath73 and @xmath74 .
[ mpluscovering ] * in general , @xmath75 depends also on the choice of @xmath68 .
however , since we are not going to rely on this fact , we can go for the lighter notation .
* @xmath76 : @xmath77 and @xmath78 are both extensions of @xmath29 .
* @xmath79 is obviously a minimal covering .
[ mplusconsistency ] @xmath80 .
referring to [ defmaximizationconstructions ] , each @xmath81 is recursively @xmath16-consistent : @xmath82 , as seen by applying first thesis of [ consistencyvsimplication ] to first branch of and second to second .
since the @xmath81 s are concentric , any finite subset of @xmath83 is included in some @xmath84 and thus consistent .
thus @xmath83 is consistent .
now a construction procedure for a model of a given sets of formulas @xmath29 is exhibited .
care is taken upon always specifying which derivation rules we will be using from time to time ; this issue is closely related to the study of the minimal requirements @xmath29 must obey in order to be able to apply such procedure .
+ the process is in three steps : first @xmath29 is enlarged to a somehow maximal family , then the latter s good properties are exploited to build the needed interpretation , and finally to show that this interpretation is a model for the derived family , and thus also for the starting subfamily . fix a formal structure @xmath1 . the free interpretation @xmath85 ( cfr .
[ freeinterprext ] ) can always be built , the matter is how to extend it to negative - arity symbols of @xmath1 . this can obviously , as discussed in [ freeinterprext ] , be done anyhow one wants , but in the present situation we have @xmath29 to guide us in the task in a natural way : set @xmath86 and call @xmath87 ( cfr [ freeinterprext ] ) .
note that @xmath88 satisfies ( is a model of ) @xmath89 while the atomic formulas of @xmath29 starting with @xmath90 are satisfied if and only if they are literal identities , i.e. of the form @xmath91 for some @xmath92 in @xmath93 . at this time
, nothing can be said about higher - order formulas , because no request on @xmath29 has been done yet .
now we fix one problem a time , starting from basics and trying to accomodate into the model given by @xmath29 first the atomic formulas with @xmath90 as a first character . this first step alone
will actually get most of the work done .
+ the idea is to apply the quotient construction introduced in according to the natural equivalence relation @xmath29 can give as soon as it is rich enough in formulas . +
that is , define the binary relation @xmath94 on @xmath93 as @xmath95 where @xmath16 is a finite set of deduction rules .
[ lemmafreeinterpretationconstruction ] 1 .
if @xmath16 includes [ assrule ] , [ antrule ] , [ reflrule ] , [ substrule ] rules ( that is , @xmath18 ) , then @xmath94 is an equivalence relation over @xmath93 .
if , moreover , @xmath29 is ( see [ defexpansion ] ) , @xmath94 is preserved through @xmath96 ( cfr . ) . 1 . the three properties of reflexivity , symmetry and transitivity to be shown to establish first part of the thesis correspond to show the derivability of the respective sequents : @xmath97 the first sequent derives directly from a rule assumed to belong to @xmath16 .
+ the second one can be derived using just the two rules : reflexivity rule gives the sequent @xmath98 which can be seen as @xmath99\frac{t_1}{x_1}$ ] ( here @xmath100 is supposed not to occur in @xmath101 ) .
antecedent rule then produces the sequent @xmath102\frac{t_1}{x_1 } $ ] , which yields , through substitution rule , @xmath102\frac{t_2}{x_1}$]@xmath103 .
+ for the last sequent , start deriving the sequent @xmath104@xmath105\frac{t_2}{x_1 } $ ] ( assuming @xmath100 not occurring in @xmath101 ) via assumption rule , and then @xmath106 via substitution rule . 2 .
let @xmath107 and @xmath108 , @xmath109 be given such that @xmath110 . by expansion hypothesis , we can strengthen this to @xmath111 . as stated in , we must show that @xmath112 let us go by cases .
+ @xmath113 : : : condition becomes @xmath114 @xmath115 by reflexivity of equivalence rule of @xmath16 . from this sequent
we obtain the sequent @xmath116 \frac{t_1}{x_1 } $ ] by antecedent rule of @xmath16 , and then @xmath117 \frac{t_1'}{x_1}\end{aligned}\ ] ] by substitution rule of @xmath16 . here , always using variable @xmath100 which is assumed not to occur in any @xmath118 or @xmath119 , we iterate this procedure to obtain the sequent @xmath120 now , since @xmath29 is expanded , all the formulas @xmath121 belong to @xmath29 , so the last sequent implies that @xmath122 . @xmath123
: : : condition becomes @xmath124 to make argument easier , we split the it into a further pair of subcases . + @xmath125 ; ; + we must prove that @xmath126 .
+ starting sequent @xmath127 is obtained using assumption rule . then by antecedence : @xmath128 and finally by substitution , as already done in this proof : @xmath129 .
iterating antecedence / substitution we get our ultimate sequent @xmath130 , which says @xmath131 since @xmath132 are all formulas of @xmath29 .
@xmath133 ; ; + suppose that @xmath134 .
since @xmath29 contains also swapped equivalences @xmath135 ( this can be shown using just reflexivity , antecedent and substitution rules ) , the same last argument could be repeated to show @xmath136 and thus ( by expansion hypothesis ) @xmath137 , a contradiction .
ultimately , we have cascaded the three constructions of [ standardconstructions ] : first free interpretation , then extension of free interpretation with a @xmath138 derived from @xmath29 , and finally ( with [ lemmafreeinterpretationconstruction ] stating the constraints on @xmath16 and the bounds between @xmath16 and @xmath29 needed to take this last step ) quotient interpretation , to get the following definition .
if @xmath18 and @xmath29 is any @xmath16-expanded set of formulas of @xmath14 , set @xmath139 this interpretation is the tool needed to work out satisfiability , and thus completeness , results in the sequel .
[ atomicformulascompleteness ] @xmath18 , @xmath29 @xmath16-expanded , @xmath140 .
then @xmath141 by cases according to the first character of @xmath142 .
case @xmath143 : : @xmath144 case @xmath145 for some @xmath146 : : @xmath147 note how consistency is not at all involved in [ atomicformulascompleteness ] s statement and proof .
that is a weak result , meaning that it works for any kind of @xmath29 .
of course , if @xmath29 is inconsistent , @xmath148 will behave inconsistently , too : given a formula @xmath142 , one can consider the set of the minterms occurring in each of its prime implicants , and thus obtain a family of sets of the form @xmath149 , with each @xmath150 in @xmath151 .
it is easy to check that @xmath152 if and only if at least one set of this family is included in @xmath29 .
previous remark hints at the fact that @xmath29 must itself satisfy some additional `` completeness '' request if one wants @xmath148 to be an interpretation for the _ whole _
that is why [ lemmafreeinterpretationmodel ] makes the request of minimal covering .
+ in a similar way , one has to request witness - completeness for @xmath29 in the following precise sense .
@xmath29 is witness - furnished iff @xmath153 there is @xmath154 .
one might say that to give an interpretation of non - atomic formulas , @xmath29 must be in some sense complete according to both @xmath155 and @xmath156 , which are the only two possible starting characters of a non - atomic formulas .
+ however , @xmath155-completeness can be consider of a more technical , and less fundamental , nature than @xmath156-completeness .
indeed , the former will be shown to be dispensable in final result , and only needed to perform the proof .
what s more , if one wants to extend present result to the case of uncountable symbol set @xmath1 ( not treated here ) , he finds that is @xmath156 completion , not the need of witnesses , which poses the hardest challenges and forces resorting to the axiom of choice to do what here is done in [ defmaximizationconstructions ] relying on countability of @xmath1 .
see @xcite .
[ lemmafreeinterpretationmodel ] @xmath18 , @xmath29 @xmath16-expanded , @xmath29 minimal covering , @xmath29 witness - furnished , @xmath157 . then @xmath158 by induction on the depth @xmath159 of @xmath142 ( as defined in [ defdepth ] ) .
triggering case @xmath160 is granted by [ atomicformulascompleteness ] . taking for proven the thesis for formulas of depth @xmath161 ,
consider a formula @xmath142 of depth @xmath162 . by cases :
@xmath142 is of the form @xmath163 : : : @xmath164 + last equivalence being given by nor and not introduction rules , one per direction , and marked equivalence being the one requiring minimal covering hypothesis .
the remaining steps go by definition and by inductive hypothesis .
@xmath142 is of the form @xmath165 : : : @xmath166}{x_m } \models \varphi \text { for some } t \in t^{s } \\ \leftrightarrow \mathcal{i } \models \varphi \frac{t}{x_m } \text { for some } t \in t^{s } \leftrightarrow \varphi \frac{t}{x_m } \in \phi \text { for some } t \in t^{s } \\ \leftrightarrow \exists x_m \varphi \in \phi\end{gathered}\ ] ] + last equivalence stands on application of [ esrule ] followed by use of expansion hypothesis ( @xmath167 ) and on assumption that @xmath29 is witness - furnished ( @xmath47 ) . here
$ ] is the equivalence class of the term @xmath92 according to @xmath94 . as a passing note , the @xmath92 occurring in previous equivalence chain
is always the same , although this accident is not exploited .
[ singlewitnessinclusion ] @xmath18 or @xmath23 ; given @xmath169 , @xmath170 : @xmath171 name @xmath172 to ease things up .
+ the following derivation : @xmath173 says @xmath174 , and thus @xmath175 and @xmath176 by . by contradiction now the negation of the latter formula is exhibited to be derivable from @xmath177 , which on the other hand is granted to be consistent .
+ suppose indeed that @xmath178 .
+ then there is a sequent @xmath179 , with @xmath61 finite subset of @xmath29 . + now , since @xmath180 , @xmath181 does not occur free in @xmath182 , permitting @xmath183 so that @xmath184 .
+ in the end , it must be @xmath185 .
this , using lastly ( which in turn employs a contradiction rule ) , equates to @xmath186 being consistent . [ lemmawitnessinclusion ] @xmath18 or @xmath23 ; if @xmath71 is @xmath16-consistent and @xmath187 is countable , there is @xmath188 such that * @xmath189 is consistent and witness - furnished . * every @xmath16-consistent superset of @xmath190 is witness - furnished .
the set of formulas starting with @xmath155 is countable with its superset @xmath14 , and can thus be written as @xmath191 .
+ define @xmath192 , and then recursively for @xmath193 @xmath194 first , the soundness of this algorithm can be checked recursively by showing that each @xmath195 is countable , so that in particular the least element in is taken over a non - empty subset of @xmath196 .
this easy step is omitted here .
+ secondly , each @xmath84 is easily proven consistent by applying [ singlewitnessinclusion ] to first branch of each time it is employed .
also , since @xmath197 , each finite subset of @xmath198 is a subset of some @xmath84 , and thus consistent .
this makes @xmath190 consistent as well .
note that the outcome of the present construction can depend on how the exist statements are initially sorted , i.e. on @xmath68 and @xmath199 ( cfr .
the parallel situation for @xmath200 in [ mpluscovering ] ) .
+ finally , the last thesis descends from the fact that any consistent superset of @xmath190 can not contain any exist - formula whose witness hasnt already been added in .
[ propsatisfiability ] hypothesis : : 1 .
@xmath18 2 .
[ hypconsistency ] @xmath71 is @xmath16-consistent .
[ hypfreecountable ] @xmath187 is countable .
thesis : : @xmath29 is satisfiable . 1 .
@xmath16 contains enough rules to allow building @xmath201 ; this is the only step in which hypotheses [ hypfreecountable ] and [ hypconsistency ] are used .
now @xmath202 is consistent because @xmath203 preserves consistency and thanks to [ mplusconsistency ] .
it is a covering , too ( [ mpluscovering ] ) .
so , by definition , it is @xmath16-maximal and , descending from [ lemmamaximalcovering ] , thus both expanded and a minimal covering .
3 . at this point ,
expandedness permits ( see [ lemmafreeinterpretationconstruction ] and [ defpreservation ] ) the construction of the henkin interpretation @xmath204 .
4 . finally , @xmath202 is witness - furnished thanks to last thesis of [ lemmawitnessinclusion ] , so we can apply [ lemmafreeinterpretationmodel ] and get that @xmath202 is satisfied by @xmath205 .
+ and so @xmath29 is .
it is time , in the end , to see that hypothesis [ hypfreecountable ] was a mere technical device to produce the proof of [ propsatisfiability ] , which can be restated without it , now that it has been granted .
[ teosatisfiability ] hypothesis : : 1 .
@xmath18 2 .
@xmath71 is @xmath16-consistent .
thesis : : @xmath29 is satisfiable .
the idea is to cast all the free variables occurring in @xmath29 into new constants to adjoin to @xmath1 , so to be able to apply [ propsatisfiability ] .
consider @xmath206 .
for each @xmath46 build the formula @xmath207 obtained by substituting each occurrence of a free variable @xmath208 with @xmath209 .
call @xmath202 the set of formulas thus obtained .
@xmath202 is consistent : : : take any finite subset @xmath210 , and compare it with the corresponding @xmath211 .
the latter is satisfiable as a set of @xmath1-formulas by virtue of [ propsatisfiability ] , and be @xmath212 a model for it .
turn @xmath212 into a @xmath213-interpretation @xmath214 by setting @xmath215 .
thanks to how we defined @xmath207 , we have @xmath216 , so @xmath214 is a model for @xmath210 .
thus the whole @xmath202 is consistent .
let then @xmath217 be a model of @xmath202 .
since @xmath218 , we can request that @xmath219 . by the same reasoning done for @xmath214 , it is shown that @xmath220 .
+ so @xmath29 is satisfiable .
[ propcompletenesswrtconsistency ] if @xmath221 , then @xmath222 it suffices to show left - to - right implication .
+ @xmath223 implies there is a model @xmath212 for @xmath29 .
correctness of sequents of @xmath16 implies ( [ theoconsistency ] ) that @xmath224 . as a major corollary of [ teosatisfiability ]
, we now show completeness of first - order calculus .
while the former is a constructive result , the latter is highly non - constructive , as it is fundamentally derived from [ teosatisfiability ] using contradiction rules .
[ theocompleteness ] hypothesis : : @xmath225 , @xmath23 , @xmath226 .
thesis : : 1 .
if @xmath142 is negative , then it is provable in @xmath227 . 2 .
@xmath142 can be proved in @xmath16 , and there exists a proof of it whose all derivation rules except at most the last are in @xmath227 . 1 .
@xmath142 is of the form @xmath228 . by contradiction , suppose @xmath229 . by [ consistencyvsimplication ] , @xmath230 , thus , using [ teosatisfiability ] , there is a model @xmath212 for @xmath231 , so that @xmath232 . but @xmath212 is also a model of @xmath29 , so by hypothesis @xmath233 .
2 . @xmath234 .
applying previous point , we find @xmath235
. then we use rule to finish .
consider a semigroup @xmath236 . by virtue of its associativity
, the binary operation @xmath237 can be seen also as a function from @xmath238 into @xmath239 .
that is , semigroup operation can unambiguously be applied to any @xmath159-ple , becoming an overloaded function . when wanting to stress this , functional notation can be employed : rather than using infix notation commonly adopted for semigroup operation : @xmath240 , one writes , for the generic @xmath159-ple : @xmath241 .
this will be handy in the sequel , besides being more adaptable to the variable argument length just established .
when , on the other hand , normal infix ( operational ) notation is used , and clarity is safe , the operation symbol @xmath237 will be possibly omitted .
+ one can push things a little further : consider that in functional notation the associativity is expressed thus : @xmath242 it then comes natural to extend the function @xmath237 to the whole @xmath243 domain by letting @xmath244 , because doing so results extended as well .
+ so when @xmath237 is used in functional notation , it will be meant to denote this latter extended function .
[ unambigdef ] a @xmath159-ple @xmath245 of subsets of @xmath246 is said unambiguous iff the restriction @xmath247 is injective .
definition [ unambigdef ] is satisfied in the trivial case of any of the sets @xmath248 being empty ( any function is injective on empty domain ) .
a subset @xmath249 is unambiguous iff @xmath250 is unambiguous ; or , equivalently , iff @xmath251 is unambiguous .
[ unambigpropagation ] if @xmath252 is a @xmath159-ple of not necessarily all distinct subsets of @xmath246 , each unambiguous , then @xmath253 is unambiguous @xmath254 , which implies that @xmath255 is unambiguous . by induction on @xmath159 .
it is useful to have a set which somehow generates the whole semigroup through its operation ; even better if this can be done in only one way .
call @xmath249 a generator iff @xmath256 is onto @xmath246 , an unambiguous generator iff is a bijection on @xmath246 .
an unambiguous generator is a generator .
an unambiguous generator is indeed useful first of all because one can extend a map on it onto the whole semigroup , in the expected manner .
[ defhomomorphicextension ] given an unambiguous generator @xmath249 and @xmath257 , set @xmath258 and define the homomorphic extension of @xmath138 as @xmath259 it is easy to check that it is defined on the whole @xmath246 and that it is an extension of @xmath138 .
[ defhomomorphicextension ] formally states what becomes the very intuitive concept of substitution as soon as @xmath246 is the free monoid over the alphabet @xmath260 , which will be the case of our interest in [ sectionformalstructure ] : take any string and substitute each occurrence in it of a certain letter with a certain string . in case @xmath138 is a finite substitution , i.e. there is a finite @xmath261 such that @xmath262 is the identity , which will be the case occurring in the sequel , we will usually employ the alternative notation @xmath263
first - order syntax construction can be found in many references . here , it is quickly introduced as it will be the material for the whole treatment .
the subject is a standard one , so little remarks are added .
there are some non - standard variations here : first , only one logical operator symbol is used , namely @xmath156 representing nor binary function ( true if and only if both its arguments are false ) ; second , polish notation is adopted ; and third , to save words and symbols when having to distinguish between function , relation , and constant symbols of the first - order alphabet , as a mere technical device , we will associate to each symbol a signed - arity ( @xmath264 ) , whose sign immediately tells about the matter ; lastly , only one quantifier is used .
these solutions are aimed at simplifying tractation ( especially in the proofs of sections ) and making statements shorter , albeit maybe less readable at times .
a formal structure is a couple @xmath265 made of an arbitrary , possibly empty , set @xmath1 ( the symbol set ) and of a function @xmath266 called signed - arity .
@xmath267 is named , respectively : * a constant iff @xmath268 * a @xmath269-ary function ( or operation ) symbol iff @xmath270 * a @xmath271-ary relation symbol iff @xmath272 so that @xmath1 is partitioned into constant , function and relation symbols .
take another infinite set @xmath2 ( the variables symbol set ) and a further , disjoint set @xmath273 , both disjoint with @xmath1 .
call @xmath274 the alphabet , and @xmath275 the non - logical alphabet .
+ consider the free semigroup @xmath276 that is , the strings of one or more letters of @xmath277 , with string concatenation @xmath237 as a semigroup operation . here
is shown how to build a couple of subsets of this semigroup in a way such that , when back to semantics , a meaning can be associated to each element of those subsets .
that is , the strings hereby constructed will have the right structure to be meaningful when each of its characters gets endowed with a ` content ' and becomes a symbol of it . these strings are indeed exactly all the strings enjoying this feature .
+ the last preparatory step is the extension of signed - arity function to all the non - logical symbols , by defining @xmath278 + consider finally two auxiliary mappings @xmath279 acting the following way : @xmath280 call terms of depth @xmath281 ( or atomic terms ) the set @xmath282 , and terms of depth @xmath283 the set @xmath284 here @xmath285 is the @xmath159-th iterate of the function @xmath286 .
+ call terms the union of the terms of any depth : @xmath287 [ termsymbols ] @xmath288 similarly , call formulas of depth @xmath281 ( or atomic formulas ) the set @xmath289 and formulas of depth @xmath283 the image of @xmath290 throught the @xmath159-th iteration of @xmath291 : @xmath292 finally , call formulas the union of formulas of any depth : @xmath293 for concision s sake , we will often use the shortcut character @xmath294 and write @xmath295 instead of @xmath43 , where @xmath142 is any formula . one
can also consider @xmath294 as a meta - symbol denoting the mapping @xmath296 .
of course , terms and formulas can be partitioned according to their depth via obvious definitions : @xmath297 * @xmath298 is a partition of @xmath15 . * @xmath299 @xmath300 now it is not hard to guess how the depth of a term or formula will be introduced : [ defdepth ] the depth of a term @xmath301 is @xmath302 or , equivalently , the natural number @xmath159 such that @xmath303 . + in the same manner ,
the depth of a formula @xmath157 is @xmath304 or , equivalently , the natural number @xmath159 such that @xmath305 .
alternatively , the depth of a formula can be recursively defined as @xmath306 and analogously for terms .
@xmath307 [ termspartition ] @xmath299 @xmath308 [ termsunambig ] @xmath309 is unambiguous in @xmath310 . by induction on @xmath159 .
note that in a free semigroup any subset of elements all of the same length is obviously unambiguous .
so @xmath311 is unambiguous . +
now suppose @xmath312 for some @xmath313 , and to have shown that @xmath309 is unambiguous : the goal is to trigger induction by showing @xmath314 and @xmath315 .
since @xmath316 both have length at least @xmath35 , they both have a first character , and this character is the first character of @xmath317 . call it @xmath318 . now the proof is by cases on @xmath318 .
@xmath319 : : by [ termspartition ] this means that both @xmath320 , which is unambiguous , so @xmath314 and @xmath315 . @xmath321 : : by [ termspartition ] this means that both @xmath322 , which is unambiguous by [ unambigpropagation ] , so @xmath314 and @xmath315 . by [ termsymbols
] this parses all the possibilities .
@xmath15 is unambiguous .
suppose @xmath323 and @xmath324 are such that @xmath325 .
call @xmath159 the greater among the depths of @xmath92 and @xmath326 . since @xmath327 and @xmath309 is unambiguous
, it must be @xmath328 and @xmath315 .
now the mapping from a term to its ordered subterms is introduced .
[ defsubtermextractor ] for @xmath329 define @xmath330 where last assignment is sensible because * as soon as @xmath331 * * @xmath92 has length at least @xmath332 . * * @xmath333 * * @xmath334 * the restriction is performed over a unambiguous domain all the results of this section can be adapted and repeated for formulas . * @xmath335 * @xmath336 is unambiguous .
note that any string in @xmath336 has length @xmath337 and that the first character of any term differs from the first character of any formula .
this grants both theses .
so the operator @xmath338 can be extended to @xmath336 .
( details todo ) let @xmath29 be a generic subset of @xmath14 .
the following definitions have to do with how many formulas we can fit into @xmath29 , especially in the light of calculus of sequent defined in [ tenrules ] .
@xmath29 is said to be a covering iff @xmath339
@xmath29 is said to be patently inconsistent iff @xmath340 , that is , iff there is @xmath157 such that @xmath341 .
@xmath29 is said to be a minimal covering iff @xmath342 is a covering , while no proper subset of it is @xmath343 is a covering and not patently inconsistent .
the two equivalences embedded in the above definition are immediate .
given a formal structure @xmath1 , an interpretation of @xmath1 is a couple @xmath344 , of which @xmath260 ( the universe of @xmath212 ) is a set and @xmath345 satisfies @xmath346 if @xmath344 is an interpretation of the formal structure @xmath1 , @xmath347 is said to be an @xmath1-structure , and @xmath348 an assignment , so that giving an @xmath1-structure and an assignment both over the same universe equals giving an interpretation of @xmath1 .
[ [ free - interpretation ] ] free interpretation + + + + + + + + + + + + + + + + + + + for any set @xmath1 of algebraic symbols , there is a standard interpretation @xmath349 of the subset @xmath350 of algebraic symbols , with universe @xmath351 ; just take @xmath352 the only checking to do , namely @xmath353 is easy .
the free interpretation is the only identical interpretation of @xmath354 , in that it satisfies @xmath355 .
[ [ freeinterprext ] ] arbitrary extensions of the free interpretation + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + @xmath356 can be extended to an interpretation of the whole @xmath1 with substantial arbitrarity by choosing @xmath357 in @xmath358 for each @xmath359 .
that is , given any mapping @xmath360 , one can associate to it an interpretation of @xmath265 by taking the free interpretation of @xmath354 and extending @xmath361 as just done , to a function we denote with @xmath362 .
note that giving such a @xmath138 is equivalent to giving a binary partition of the string set @xmath363 [ [ quotient - interpretation ] ] quotient interpretation + + + + + + + + + + + + + + + + + + + + + + + suppose to have an @xmath1-interpretation @xmath364 and an equivalence relation @xmath365 ( whose projector let be denoted by @xmath366 ) preserved through @xmath367 , which means @xmath368 where @xmath369 is the equivalence relation on @xmath370 obtained by setting @xmath371 .
this property permits building the projected function @xmath372 it is obvious that @xmath373 is still an @xmath1-interpretation .
[ [ assignment - mutation ] ] assignment mutation + + + + + + + + + + + + + + + + + + + denote with @xmath374 the interpretation @xmath375 obtained from @xmath364 by setting and @xmath376 are considered as relations , which permits seeing them as subsets of the cartesian product of domain with codomain . ] @xmath377 , where @xmath378 .
less formally , we keep the structure of the interpretation while changing the assignment of variables symbols .
the case of interest to us will be that of @xmath68 equating @xmath379 except for a finite subset @xmath380 of @xmath2 , in which case we write @xmath381 an interpretation assigns a meaning to atomic terms and to each operation symbol .
obviously this suffices to recursively assign a meaning ( i.e. a value in the universe of the interpretation ) to each term by revisiting what done in [ termsandformulas ] and calculating the value of a term from the value of its ( lower - depth ) subterms .
+ once done this , one can reiterate an analogous process , and recursively assign a meaning ( i.e. a value in @xmath382 ) to each formula by regarding it as made of boolean symbols and subformulas , and ultimately of boolean symbols and atomic formulas , and in turn the latter as made of relation symbols , @xmath90 s and terms .
+ formally , this is done by extending @xmath367 of the given interpretation @xmath344 first to all @xmath15 and then to all @xmath14 , as follows . before formalization
, it should be noted that it is customary to abuse a bit the notation and use the interpretation symbol @xmath212 altogether in place of the proper function symbol @xmath367 , so one can write statements like , e.g. , @xmath383 and @xmath384 .
define , for @xmath385 : @xmath386 then recursively for the definition of @xmath387 .
basically , it returns all subterms and subformulas of a given term / formula into a @xmath159-ple .
] : @xmath388 @xmath389 @xmath390 an interpretation @xmath212 satisfies @xmath71 , otherwise said that @xmath212 is a model of @xmath29 , iff @xmath391 .
this is expressed in symbols as @xmath392 .
[ cols= " < , > " , ] 99 heinz - dieter ebbinghaus , jrg flum , wolfgang thomas , mathematical logic , 1994 springer l. henkin , the completeness of the first - order functional calculus , journal of symbolic logic , vol 14 , n 3 , 159 - 166 , 1949 .
katz , r.h . and
borriello , g. , contemporary logic design , 1994,benjamin / cummings redwood city , ca van heijenoort , j. from frege to gdel : a source book in mathematical logic , 1879 - 1931 ; 1967 , harvard univ press | a henkin - style proof of completeness of first - order classical logic is given with respect to a very small set ( notably missing cut rule ) of genzten deduction rules for intuitionistic sequents .
+ insisting on sparing on derivation rules , satisfiability theorem is seen to need weaker assumptions than completeness theorem , the missing request being exactly the rule @xmath0 , which gives a hint of intuitionism s motivations from a classical point of view . +
a bare treatment of standard , basic first - order syntax somehow more algebraic - flavoured than usual is also given . |
A major U.S. government study on rats has found a link between cellphones and cancer, an explosive finding in the long-running debate about whether mobile phones cause health effects.
The multiyear, peer-reviewed study, by the National Toxicology Program, found “low incidences” of two types of tumors in male rats that were exposed to the type of radio frequencies that are commonly emitted by cellphones. The tumors were gliomas, which are in the glial cells of the brain, and schwannomas of the heart.
... ||||| A study by the Department of Health and Human Services's National Toxicology Program discovered a link between cellphone radiation and two types of cancer. Reporting on its partial results so far, researchers found low incidences of heart and brain tumors in male rats. (Reuters)
First things first: No one has proven that cellphones cause cancer. No one has proven that cellphones cause cancer. In fact, most research suggests otherwise! But you might not realize that, based on some news circulating Friday morning. Many publications, including the Wall Street Journal and Mother Jones, are trumpeting the results of a U.S. government study that links cellphones to tumor growth.
But while the WSJ ran with the scary "Cellphone-Cancer Link Found in Government Study," something like "Research That Hasn't Been Vetted Yet Shows Possible Link Between Cellphones and Cancer in Male Rats" might have been more appropriate.
Less sexy! But also a lot less misleading.
The study, released on Thursday after the results leaked online, is the result of a $25 million, multi-year effort from the National Toxicology Program (NTP). But it hasn't been peer reviewed — despite implications to the contrary by the WSJ — because it hasn't been formally submitted to a scientific journal and accepted for publication, during which time outside experts would have had the opportunity to pinpoint possible errors or exaggerations in the data and analysis. Several experts reportedly reviewed the work before it was announced, but the researchers have not yet made all of their data public.
[Why it’s too early to get excited about this ‘unprecedented’ new cancer treatment]
Ron Melnick, who was the lead investigator on the study until he retired in 2009, told STAT News that he was asked to review the data and found that they “indicated that there were increased tumor responses in the brain and the heart."
“Where people were saying there’s no risk, I think this ends that kind of statement,” he told the WSJ.
The researchers exposed mice and rats to radio-frequencies commonly used by wireless electronics, at doses comparable to a human's typical exposure. Of the male rats dosed with radiation, the study authors report, 2 to 3 percent contracted gliomas, or tumors of the glial cells of the brain, and 6 to 7 percent percent developed schwannoma tumors in their hearts. None of the non-dosed rats developed any tumors. But STAT points out that it's unusual that none of these non-dosed rats randomly developed tumors on their own, and that the cancer rates in the dosed rats might actually be pretty similar to what you'd usually expect in a random rat population.
[Addicted to your cellphone? These photos may make you uncomfortable.]
There was no significant cancer uptick in the female rats dosed with radiation, and the researchers have not released their data on male or female mice.
All of this is to say that it's way too soon to take these findings as a reason to toss your phone out the window. We've explained before that single studies are basically useless on their own (here's why) and that's still the case. This research will almost certainly inspire new projects that try to replicate the troubling results, and that's great. But when publications blast every contrarian new finding as a groundbreaking absolute truth, it makes the public less able to develop informed opinions.
"There are arguments in the literature now that we are at the beginning of an epidemic of cancers," Chris Portier, former associate director of the NTP, told Mother Jones. "There are arguments against that. It is not clear who is right. I have looked through it. It's a mixed bag."
Indeed, most studies examining the human population over time have concluded no association between cellphone use and increased rates of cancer. Some have argued that we just haven't been using cellphones long enough to see the ill-effects borne out, but the University of Sidney's Simon Chapman recently argued against this line of thinking.
"That is not what we see with cancer," he wrote in an op-ed for Quartz. "We see gradual rises moving toward peak incidence, which can be as late as 30 to 40 years (as with lung cancer and smoking)." And his research — and that produced by other scientists — has failed to show the start of such a trend.
Maybe this study really is a major turning point in understanding of the risk of cell phone usage. But it's way too soon to tell.
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Calm down: Herpes probably isn’t going to give you Alzheimer’s ||||| A major new study provides evidence of a possible link between cellphone exposure and cancer, at least in rats — findings that are likely to spark a fierce new debate about the 21st century’s most ubiquitous tech gadget.
When researchers exposed rats to the radiofrequency radiation emitted by cellphones, they saw higher incidence of two types of cancer: malignant gliomas in the brain and schwannomas in the heart. The increased risk was relatively small, but if the findings translate to humans — still an unknown — it could have a large public health impact, given the widespread use of cellphones worldwide.
The highly anticipated, $25 million study was conducted by the US National Toxicology Program. Partial results were released late Thursday, before full results were available, because of intense public interest, according to John Bucher, associate director of the NTP.
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“We feel that these findings are potentially of interest to the discussion over the cellphone safety issues,” Bucher said. “We felt it was important to get the word out.”
However, “the results from our studies are far from definitive at this point,” he said. For human health, “this may have relevance. This may have no relevance.”
The study had some head-scratching findings. For instance, it found that despite developing more tumors, male rats exposed to radiation for about nine hours every day also lived longer than a control group not exposed to radiation. In addition, it was unusual that no cancers occurred in the control group in this study. The incidence of malignant gliomas in male rats exposed to radiation — 2.2 to 3.3 percent — was within the range seen in nonexposed rats in previous studies, the authors said.
Still, the authors said that the brain and heart tumors observed in rats exposed to the radiofrequency radiation are similar to malignancies seen in some epidemiological studies of cellphone use. They say their findings “appear to support” the World Health Organization’s classification of cellphones as a possible carcinogen. (That’s the same classification given to coffee and talcum powder.)
Elisabeth Cardis, the lead investigator on the study that spurred that classification, said the NTP report provided “really quite novel findings.”
“A lot of people felt that the issue was closed; there’s nothing there and you can just move on. The release of these results now … really raises the question about whether, in fact, there is a real effect,” she said.
Population implications
But other population-level studies in humans have found no increased risk, and the incidence of brain cancer has not risen in recent decades as cellphone use has exploded.
“These data will probably raise the level of suspicion that there might be a problem. I didn’t see them as strong enough to say that there’s really a problem,” said Kenneth Foster, a bioengineering professor at the University of Pennsylvania who has studied radiation and health. “It’s really hard to know just how to interpret these results.”
He noted in particular the finding that male rats exposed to radiation lived longer than those not exposed to radiation.
Michael Lauer, deputy director of extramural research for the NIH, who provided comment to the NTP on the study, said that because of the small sample size, the study’s findings are suspect. “It is much more likely than not that this is not a true finding,” he said.
As recently as Wednesday, the NIH said the study was still under review by unnamed additional experts.
“It is important to note that previous human, observational data collected in earlier, large-scale population-based studies have found limited evidence of an increased risk for developing cancer from cellphone use,” the NIH said in a statement.
The agency did not immediately respond to a request for comment on the report’s release, which followed a Wednesday report by the website Microwave News that disclosed what the researchers had found.
The researchers have more data stockpiled that they haven’t reported. They say the rest of the results from the study will likely trickle out starting in late 2017.
Potential firestorm
The new study has the potential to start a firestorm. Until now, there have been conflicting results from other research about whether cellphones cause cancer, but the general takeaway from official authorities was that there is no definitive link — as the NIH statement reiterates.
Dr. Jonathan Samet, director of the University of Southern California’s Institute for Global Health, said one of the big takeaways is “we really need a more serious research agenda.”
“I think the public needs to know if there’s any risk,” he said. “I think this is something that needs to be taken as a need for further research and investigation. … We should not say there is no risk.”
The findings could jeopardize the conventional wisdom at a time when the number of Americans who own a cellphone has exceeded 90 percent in recent years.
“None of us expected them to find anything in this study. I’ve been quoted as saying it’s a total waste of money,” said David Carpenter, director of the Institute for Health and the Environment at the University of Albany.
The results have been long anticipated. An NIH official told Congress in 2009 that the results would likely be released in 2014, but their release appeared to be prompted only by this week’s leak.
“We’ve been waiting a long time for this study, far too long for this study,” said Joel Moskowitz, director and principal investigator at the Center for Family and Community Health at the University of California, Berkeley.
Still, he added: “The debate will keep going on, I’m sure. This is not going to be the definitive study.”
This story has been updated with new details about the study and previous research on cellphones. ||||| Federal scientists released partial findings Friday from a $25-million animal study that tested the possibility of links between cancer and chronic exposure to the type of radiation emitted from cell phones and wireless devices. The findings, which chronicle an unprecedented number of rodents subjected to a lifetime of electromagnetic radiation starting in utero, present some of the strongest evidence to date that such exposure is associated with the formation of rare cancers in at least two cell types in the brains and hearts of rats. The results, which were posted on a prepublication Web site run by Cold Spring Harbor Laboratory, are poised to reignite controversy about how such everyday exposure might affect human health.
Researchers at the National Toxicology Program (NTP), a federal interagency group under the National Institutes of Health, led the study. They chronically exposed rodents to carefully calibrated radio-frequency (RF) radiation levels designed to roughly emulate what humans with heavy cell phone use or exposure could theoretically experience in their daily lives. The animals were placed in specially built chambers that dosed their whole bodies with varying amounts and types of this radiation for approximately nine hours per day throughout their two-year life spans. “This is by far—far and away—the most carefully done cell phone bioassay, a biological assessment. This is a classic study that is done for trying to understand cancers in humans,” says Christopher Portier, a retired head of the NTP who helped launch the study and still sometimes works for the federal government as a consultant scientist. “There will have to be a lot of work after this to assess if it causes problems in humans, but the fact that you can do it in rats will be a big issue. It actually has me concerned, and I’m an expert.”
More than 90 percent of American adults use cell phones. Relatively little is known about their safety, however, because current exposure guidelines are based largely on knowledge about acute injury from thermal effects, not long-term, low-level exposure. The International Agency for Research on Cancer in 2011 classified RF radiation as a possible human carcinogen. But data from human studies has been “inconsistent,” the NTP has said on its website. Such studies are also hampered by the realities of testing in humans, such as recall bias—meaning cancer patients have to try to remember their cell phone use from years before, and how they held their handsets. Those data gaps prompted the NTP to engage in planning these new animal studies back in 2009.
The researchers found that as the thousands of rats in the new study were exposed to greater intensities of RF radiation, more of them developed rare forms of brain and heart cancer that could not be easily explained away, exhibiting a direct dose–response relationship. Overall, the incidence of these rare tumors was still relatively low, which would be expected with rare tumors in general, but the incidence grew with greater levels of exposure to the radiation. Some of the rats had glioma—a tumor of the glial cells in the brain—or schwannoma of the heart. Furthering concern about the findings: In prior epidemiological studies of humans and cell phone exposure, both types of tumors have also cropped up as associations.
In contrast, none of the control rats—those not exposed to the radiation—developed such tumors. But complicating matters was the fact that the findings were mixed across sexes: More such lesions were found in male rats than in female rats. The tumors in the male rats “are considered likely the result of whole-body exposure” to this radiation, the study authors wrote. And the data suggests the relationship was strongest between the RF exposure and the lesions in the heart, rather than the brain: Cardiac schwannomas were observed in male rats at all exposed groups, the authors note. But no “biologically significant effects were observed in the brain or heart of female rats regardless of modulation.” Based on these findings, Portier said that this is not just an associated finding—but that the relationship between radiation exposure and cancer is clear. “I would call it a causative study, absolutely. They controlled everything in the study. It’s [the cancer] because of the exposure.”
Earlier studies had never found that this type of radiation was associated with the formation of these cancers in animals at all. But none of those studies followed as many animals, for as long or with the same larger intensity exposures, says Ron Melnick, a scientist who helped design the study and is now retired from the NTP.
The new results, published on Web site bioRXiv, involved experiments on multiple groups of 90 rats. The study was designed to give scientists a better sense of the magnitude of exposure that would be associated with cancer in rodents. In the study rats were exposed to RF at 900 megahertz. There were three test groups with each species of each sex, tested at different radiation intensities (1.5, three and six watts per kilogram, or W/kg), and one control group. (The lowest-intensity level roughly approximates the levels allowed by U.S. cell phone companies, which is 1.6 W/kg.) “There are only 90 animals per group, so because there is a trend—and this is the purpose of these assays where you do multiple doses you extrapolate downward and calculate a risk for humans from those trends—so that information is useful. Probably what caused cancer at the high doses will cause cancer at lower doses but to a lesser degree,” Portier says.
Rodents across all the test groups were chronically exposed to RF for approximately nine hours spread out over the course of the day. (Their entire bodies were exposed because people are exposed to such radiation beyond their heads, especially when they carry them or store them in their bras, says John Bucher, the associate director of the NTP.) During the study the rats were able to run around in their cages, and to eat and sleep as usual. The experiments also included both types of modulations emitted from today’s cell phones: Code Division Multiple Access and Global System for Mobile. (Modulations are the way the information is carried, so although the total radiation levels were roughly the same across both types, there were differences in how radiation is emitted from the antenna—either a higher exposure for a relatively short time or a lower exposure for a longer time.) Overall, there was no statistically significant difference between the number of tumors that developed in the animals exposed to CDMA versus GSM modulations. With both modulations and tumor types, there was also a statistically significant trend upward—meaning the incidence increased with more radiation exposure. Yet, drilling down into the data, in the male rats exposed to GSM-modulated RF radiation the number of brain tumors at all levels of exposure was not statistically different than in control males—those who had no exposure at all. “The trend here is important. The question is, ‘Should one be concerned?’ The answer is clearly ‘Yes.’ But it raises a number of questions that couldn’t be fully answered, ” says David Carpenter, a public health clinician and the director of the Institute for Health and the Environment at the University at Albany, S.U.N.Y.
The findings are not definitive, and there were other confusing findings that scientists cannot explain—including that male rats exposed to the radiation seemed to live longer than those in the control group. “Overall we feel that the tumors are likely related to the exposures,” says Bucher, but such unanswered questions “have been the subject of very intense discussions here.”
The NTP released the partial findings on Friday after an online publication called Microwave News reported them earlier this week. The program will still be putting out other results about the work in rats and additional findings about similar testing conducted in mice. The NIH told Scientific American in a statement, “This study in mice and rats is under review by additional experts. It is important to note that previous human, observational data collected in earlier, large-scale population-based studies have found limited evidence of an increased risk for developing cancer from cell phone use.” Still, the NTP was clearly expecting these findings to carry some serious weight: Ahead of Friday’s publication the NTP said on its Web site that the study (and prior work leading to these experiments) would “provide critical information regarding the safety of exposure to radio-frequency radiation and strengthen the science base for determining any potential health effects in humans.”
In response to media queries, cell phone industry group CTIA–The Wireless Association issued a statement Friday saying that it and the wireless industry are still reviewing the study’s findings. “Numerous international and U.S. organizations including the U.S. Food and Drug Administration, World Health Organization and American Cancer Society have determined that the already existing body of peer-reviewed and published studies shows that there are no established health effects from radio frequency signals used in cellphones,” the CTIA statement said.
The Federal Communications Commission, which had been briefed by NIH officials, told Scientific American in a statement, “We are aware that the National Toxicology Program is studying this important issue. Scientific evidence always informs FCC rules on this matter. We will continue to follow all recommendations from federal health and safety experts including whether the FCC should modify its current policies and RF exposure limits.”
This animal study was designed primarily to answer questions about cancer risks humans might experience when they use phones themselves, as opposed to smaller levels of exposure from wireless devices in the workplace or from living or working near cell phone towers. But it may have implications for those smaller levels as well, Portier says.
The findings shocked some scientists who had been closely tracking the study. “I was surprised because I had thought it was a waste of money to continue to do animal research in this area. There had been so many studies before that had pretty consistently not shown elevations in cancer. In retrospect the reason for that is that nobody maintained a sufficient number of animals for a sufficient period of time to get results like this,” Carpenter says.
Exposing rodents to radiation for this type of experiment is a tricky business. First, scientists need to be able to calculate exactly how much the rats should be exposed to relative to humans. Too much exposure would not be a good proxy for human use. And with finely calculated low-level exposure rates, scientists still need to be sure they are not going to heat the animals enough to kill them or to cause other health problems. (Subsequent work will be published on the animals’ temperatures.)
The fact that scientists were able to expose animals to nonionizing radiation (like that emitted by cell phones) and those animals went on to develop tumors but that exposure did not significantly raise the animals' body temperatures was “important” to release, Bucher says.
There are safety steps individuals can take, Carpenter says. Using the speakerphone, keeping the phone on the desk instead of on the body and using a wired headset whenever possible would help limit RF exposure. “We are certainly not going to go back to a pre-wireless age,” he says. But there are a number of ways to reduce exposure, particularly among sensitive populations.”
Editor's Note (5/27/16, 2:10 P.M.): This story was updated to reflect information provided during an NTP press conference and a statement from an industry group. ||||| A giant U.S. study meant to help decide whether cellphones cause cancer is coming back with confusing results.
A report on the study, conducted in rats and mice, is not finished yet. But advocates pushing for more research got wind of the partial findings and the U.S. National Toxicology Program has released them early.
The findings are giving new life to the longstanding debate over whether cellphone use might cause cancer.
They suggest that male rats exposed to constant, heavy doses of certain types of cellphone radiation develop brain and heart tumors.
But female rats didn’t, and even the rats that developed tumors lived longer than rats not exposed to the radiation.
The National Toxicology Program, part of the National Institutes of Health, is still analyzing the findings. But John Bucher, associate director of the program, said the initial findings were so significant that the agency decided to release them. "We felt it was important to get that word out," Bucher told reporters on a telephone briefing.
"Overall, we feel that the tumors are likely to be related to the exposures."
What they do not show is whether humans are at any risk from using cellphones, or whether using a headset or keeping them away from the head and body might make a difference.
"It may well be that current cellphone use is safe." "It may well be that current cellphone use is safe."
Dr.Otis Brawley, chief medical officer for the American Cancer Society, says it's good science and will change the way people think about cellphones and cancer risk.
"The findings are unexpected; we wouldn’t reasonably expect non-ionizing radiation to cause these tumors," he said.
"This is a striking example of why serious study is so important in evaluating cancer risk. It’s interesting to note that early studies on the link between lung cancer and smoking had similar resistance, since theoretical arguments at the time suggested that there could not be a link."
Brain tumors are rare. About 23,770 malignant tumors of the brain or spinal cord will be diagnosed this year, according to the American Cancer Society, and 16,000 people will die from them. And there has not been an increase in rates since the 1990s, when cellphones started to be used.
"It is very reassuring in fact that there has been no dramatic increase. It may well be that current cellphone use is safe," Bucher said. Bucher said he has not changed his own cellphone habits because of the findings.
The partial report covers what the researchers considered the most worrying findings.
“The occurrences of two tumor types in male Harlan Sprague Dawley rats exposed to RFR (radiofrequency radiation), malignant gliomas in the brain and schwannomas of the heart, were considered of particular interest, and are the subject of this report,” the team writes in its report. Sprague Dawley rats are a common type of lab rat.
“These findings appear to support the International Agency for Research on Cancer (IARC) conclusions regarding the possible carcinogenic potential of RFR.” IARC, the cancer arm of the World Health Organization, said in 2011 it was possible the devices might cause cancer and recommended further study.
Related: Questions About Cellphone Use and Cancer
Cellphones are used by billions of people around the world — 92 percent of American adults own a cellphone, according to Pew Research Center. Children as young as toddlers carry and use the devices for hours on end, so any hint that they might somehow cause cancer would be of enormous concern.
Previous studies have had very mixed results. One study found that holding a mobile phone next to the head might warm up brain cells, but there was not any clear consequence of that. Studies on rats are considered of only partial reliability, because lab rats have their own unpredictable vulnerabilities to cancer.
For the experiment, a contract lab in Chicago generated cellphone signals, both in the GSM and CDMA radio systems — two major systems used by cellphone providers. They directed the signals into cages with pregnant rats, and then kept the signals focused on the rat pups for 10 minutes on, 10 minutes off, nine hours a day, as they grew for two years.
So called control rats were raised nearby without radiation exposure.
There was little effect on the newborn rats, except the pups appeared to be very slightly lighter when the mothers were exposed to the signals. | – The concern that cellphones may lead to cancer has been bounced around for years—and partial results from a $25 million government study purport to have found such a link, though with major caveats, the Wall Street Journal reports. Per the so-far results of the multiyear National Toxicology Program study (which the Journal says has been peer reviewed, but the Washington Post says has not), "low incidences" of two types of tumors—brain "gliomas" and heart "schwannomas"—developed in rats exposed to high doses of radiofrequency radiation, or RFR, like that emitted from mobile phones. "Even a very small increase in the incidence of disease resulting from exposure to [RFR] could have broad implications for public health," the report released Thursday said. But, adds associate NTP chief John Bucher, “the results from our studies are far from definitive at this point,” per USA Today. For humans, “this may have relevance. This may have no relevance.” To conduct the study, scientists directed RFR signals into the cages of pregnant rats, then into the cages of the babies for a total of nine hours every day for two years. In the end, 2% to 3% of dosed males contracted gliomas, and 6% to 7% contracted schwannomas. But "there was no significant cancer uptick in the female rats dosed with radiation," per the Post—and the radiation rodents actually lived longer than the control rats. That, in addition to other factors, has left some experts skeptical, noting that the study has only been partially completed and that rats are prone to what NBC News calls their "own unpredictable vulnerabilities to cancer," meaning humans may not face the same risks. All of this has led the Post to suggest a better headline for this report may be "Research That Hasn't Been Vetted Yet Shows Possible Link Between Cellphones and Cancer in Male Rats." Still, a former head of the NTP tells Scientific American, "It actually has me concerned, and I'm an expert." The full report is set to be released next year. |
for many years , the size and complexity of the triticeae genomes , namely , wheat ( 17 gb , hexaploid ) , barley ( 5 gb , diploid ) , and rye ( 8 gb , diploid ) , have hampered the development of genomics and its application to breed crops with improved composition and characteristics designed to satisfy the needs of consumers , processors , and producers . despite the recognition that a reference genome sequence is key to accelerating crop improvement , the triticeae are the last major crops for which a complete genome sequence is not available ( feuillet and eversole 2007 ) .
thus , the establishment of genome sequence enabled technology platforms for the triticeae has lagged behind advances in other cereal crops such as corn and rice . in the past decade , however , extensive efforts to develop whole - genome and chromosome - specific bacterial artificial chromosome ( bac ) libraries ( allouis et al . 2003 ; safar et al . 2004 ) , extensive est collections ( itec http://avena.pw.usda.gov/genome/ ; lazo et al . 2004 ; zhang et al . 2004 ) , transformation systems , wild germplasm and mutant collections , as well as dna chips have permitted the establishment of large - scale genomics resources and research programs aimed at enabling high - quality sequencing of the triticeae genomes . given their complexity , in particular that of the hexaploid wheat genome , physical maps must be established as a scaffold for sequence assembly as it is simply not possible to achieve a reference genome sequence using whole genome shotgun approaches ( feuillet et al .
2011 ; ariyadasa and stein 2012 ) . in the past 4 years , a number of initiatives such as the international wheat genome sequencing consortium ( www.wheatgenome.org ; feuillet and eversole 2007 ) , the international barley sequencing consortium ( www.barleygenome.org ) , the uk wheat consortium ( http://www.wheatbp.net/wheatbp/documents/doc_research.php ) , and the european triticeaegenome fp7 project ( www.triticeaegenome.eu ) have developed a suite of genomic resources and knowledge to provide the foundation for physical mapping and sequencing the wheat and barley genomes . before the development of these resources , map - based cloning was quite laborious and time - consuming , and consequently , only a few genes have been isolated in the triticeae ( bschges et al .
2002 ; 2008 ; huang et al . 2003 ; yan et al . 2003 ; charles et al . 2009 ; fu et al . 2009 ; turner et al . 2005 ; komatsuda et al . 2007 ;
2008 ; nair et al . 2010 ; faris et al . 2010 ; breen et al .
this was due in part to the challenge of walking efficiently along the chromosomes in repetitive sequence regions with the difficulty of identifying unique probes for screening bac libraries . with more than 80 % of the sequence identified as transposable elements ,
the issues are acute in the triticeae genomes , although the deployment of markers that cross the often unique boundaries between repetitive elements has reduced the problem to some degree ( flavell et al .
chromosome walking is no longer necessary and , assuming the genetic resolution is high enough , physical maps enable direct landing at the target site thereby enabling more efficient gene cloning . in the absence of complete genome sequences and given the relatively high gene order conservation ( collinearity ) observed in the grass genomes , genomics studies in the triticeae have utilized comparative genomics approaches with other grass genomes .
to date , five genomes relevant to the triticeae have been sequenced , namely rice , brachypodium , sorghum , maize , and foxtail millet ( irgsp 2005 ; ibi 2010 ; paterson et al .
comparisons between these different genomes enable the identification of conserved gene regions that can support molecular marker design and identify candidate genes for traits that are well conserved between species .
hence , the high - quality rice genome sequence ( irgsp 2005 ) combined with the sequences of a number of genomes from the other grasses ( brachypodium , sorghum , maize ) was used to develop molecular markers such as the conserved orthologous set ( cos ) molecular markers ( bertin et al . 2005 ; quraishi et al . 2009 ) and to accelerate discovery of wheat and barley genes ( fu et al .
however , genes such as very recently duplicated genes and those involved in end use quality ( for example bread , pasta ) , rapidly evolving genes such as disease resistance genes , as well as genes involved in large regulatory networks are more species - specific , and thus , it is crucial to have access to genomic resources and a reference sequence of the target genome .
while for barley , whole genome bac libraries have been produced ( schulte et al . 2011 ) , the generation of bac clones from flow - sorted chromosomes ( safar et al . 2004 ; af et al . 2010 ) and chromosome arms ( reviewed in dolezel et al . 2012 ) has been key to reducing the complexity of the hexaploid wheat genome analyses .
typically , libraries of 30,00090,000 bac clones are generated from the flow sorting of approximately a million chromosomes ( http://olomouc.ueb.cas.cz/dna-libraries/cereals ) to give a coverage of over 10 for the predicted chromosome size ( dolezel et al .
the bac libraries are then fingerprinted using snapshot labelling and analysis ( luo et al .
2003 ) , using five restriction endonucleases , and bac contigs are assembled generally using the fingerprinted contig ( fpc ) software ( soderlund et al .
2010 ) and good results were obtained in wheat , as exemplified by the construction of the first physical map of the 1 gb wheat chromosome 3b ( paux et al . 2008 ) , the length of the physical contigs was slightly lower than in small model genomes . sequencing bac contigs ( choulet et al .
in fact , due to the high level of repetitive dna in the triticeae genomes , very stringent criteria must be used to ensure a reliable assembly with the fpc software .
this , in turn , often results in short contig lengths as well as an unreliable assembly in some difficult regions . to address these problems , frenkel et al .
the ltc algorithm reduces the rate of false connections and q - clones by systematically exploring the topological contig structure and performing iterative clone clustering and ordering so that highly reliable and contigs longer than in fpc are recovered .
the ltc detects weak connections in contigs obtained by fpc and through iterative steps undertakes their repair .
a further improvement in the reliability of physical map construction can be obtained using the power of next - generation sequencing technologies .
keygene ( www.keygene.com ) recently developed a new approach called whole genome profiling ( wgp , van oeveren et al .
2011 ) that is based on the sequencing of the ends of restriction endonuclease fragments after digestion of bac pools .
the application of wgp to a subset of the wheat chromosome 3b physical map ( philippe et al .
2012 ) demonstrated that this is a viable approach for a complex genome such as wheat and that it reduces the amount of chimeric and misassembled clones compared to the snapshot method while providing sequence tag information that can be used to support pooling strategies for sequencing .
thus , robust methodologies and protocols are now in place for assembling reliable physical maps in the triticeae genomes .
the full potential of physical maps in supporting map - based cloning and marker development for breeding can only be achieved when the bac contigs are linked sufficiently to genetic and phenotypic maps .
thus , once physical maps have been assembled , it is essential that the bac contigs are anchored at high density with molecular markers .
this requires the development of thousands of markers followed by their assignation to the genetic and physical maps . in the triticeae ,
large collaborative efforts have been deployed in the past 15 years to develop est and ssr markers for genetic mapping enabling the construction of genetic maps that carry several hundreds of markers ( wheat.pw.usda.gov/gg2/index.shtml ) .
however , it is only with the advent of ngs technologies that high throughput development and genotyping of snp markers progressed to a significant degree in wheat and barley .
the deployment of kaspar - based assays for snps in wheat provided the basis for a map of avalon cadenza with 2,923 snps ( allen et al .
recently , large transcriptome sequencing and resequencing efforts in australia and the usa enabled the development of a 9k infinium wheat snp - chip ( akunov , personal communication ) . in barley ,
comprehensive sets of several thousands of snp markers have been successfully developed and mapped in numerous populations ( close et al .
2012 ) . with additional gene - based snp datasets originating from programs in the uk ( http://www.wheatisp.org ;
allen et al . 2011 ) and from 5,000 cos - snps designed in the triticeaegenome project , a 90k snp - chip is currently under design and should be available in the near future ( akhunov , personal communication ) .
focusing on the transcriptome enables a reduction in complexity that also can be achieved by the digestion of genomic dna with restriction enzymes and sequencing of selected fragments .
genotyping by sequencing ( gbs ) technologies , developed originally in maize , have been applied to wheat and barley ( elshire et al . 2011
2012 ) thereby providing another platform for dna sequence - based ordering of reference points along the triticeae genomes . with this approach ,
34,396 snps were mapped by gbs in the oregon wolfe barley reference population , while 19,720 snps were mapped in the synthetic w97846 opata85 reference wheat population . because they rely on sequence information , the snp- and gbs - based approaches provide thousands of sequence tags that can be integrated into physical maps in silico thereby increasing the efficiency of anchoring strategies .
this more direct integration of bac sequencing and anchoring to genetic maps was carried out successfully in the rice genome sequencing program using bac - end sequences ( reviewed in ariyadasa and stein 2012 ) , and it is currently being applied in wheat and barley ( ibsc 2012 ) . the in silico , sequence - based anchoring complements the well - established process of identifying known molecular markers in bac pools using pcr ( paux et al .
2008 ) as well as the broad range of hybridization array technologies that are available ( reviewed in ariyadasa and stein 2012 )
. genetic mapping in the triticeae genomes is difficult partly as a result of the very low rate of recombination observed in the centromeric and pericentromeric regions that can represent up to one half of an entire chromosome ( birchler et al . 2009 ; kanisay and dawe 2009 ) . on wheat chromosome 3b
, it was estimated that 90 % of crossing over occur in only 40 % of the chromosome , mostly in the telomeric regions , whereas 27 % of the chromosome did not show any crossing over ( saintenac et al .
sufficient resolution in ordering physical contigs to genetic maps using molecular markers can be obtained when utilizing mapping populations with high recombination frequencies .
this can be achieved using recombinant inbred line ( ril ) populations of several thousand individuals .
two populations of 2,600 and 4,000 rils have been produced for this purpose in wheat ( renan chinese spring ) and barley ( barke morex ) , respectively , in the triticeaegenome project with the rationale of using parents that are the references for genome sequencing and physical mapping , i.e. , chinese spring in wheat and morex in barley .
this complements the continued efforts of the international triticeae mapping initiative to develop a reference population for genetic mapping in wheat using a cross between the synthetic wheat w7984 opata m85 population .
a new population of 2,039 rils has been established recently with a core set of 42 ssr markers used to genotype the lines and facilitate a community - base effort to build a detailed map ( sorrells et al .
( 2011 ) reported 215 doubled haploid lines that were genotyped with 1,446 molecular markers .
furthermore , multi - parent advanced generation intercross populations originating from multiple founder lines ( typically 8 to 16 ) and therefore relying on a larger diversity and amount of recombination events than bi - parental populations have been established in wheat ( mackay and powell 2007 ; huang et al .
these are currently being tested for anchoring physical maps in different projects . in the regions near the centromeres or within large blocks of heterochromatin
where little if any recombination occurs , it is not possible to reliably anchor and order a physical map .
targeting these regions is important , however , as it is now clear that genes are present all along the physical maps ( choulet et al .
2011 ) , including in bac clones assigned to the centromeres and to retrotransposable element - rich regions of chromosomes .
genes , including the important vernalisation gene vrn - d4 , have been mapped to the centromere region ( yoshida et al . 2010 ) . in another study ,
the characterization of a 0.8-mb dna segment from chromosome 3b that was composed almost entirely of transposable elements except for a small gene island of three conserved genes ( breen et al .
thus , an alternative strategy for targeting centromeres and other repetitive sequence - rich regions of the chromosomes where recombination is low has been established following radiation hybrid mapping approaches that are widely used in animal genetics .
radiation hybrid mapping relies on assaying radiation - induced chromosomal fragments with molecular markers defined by the physical map under study ( riera - lizarazu et al .
the frequency of markers remaining together on the same chromosome fragment defines a measure of how physically close the markers are to each other .
rh mapping was evaluated during the construction of the 3b physical map using a panel of 184 rh lines tested with 65 isbp markers .
a resolution of approximately 263 kb per break was observed ( paux et al .
in particular , for the terminal bin of chromosome 3bl ( 3bl7 - 0.63 - 1.00 ) , 35 loci corresponding to 32 loci were ordered and confirmed the physical map established using markers ordered by standard recombination - based mapping ( paux et al . 2008 ) .
more recently , the same panel was used to establish a high density rh map with 541 marker loci anchored to chromosome 3b spanning a total distance of 1871.9 cr ( kumar et al .
the observations on the existence of a core set of coding genes that is conserved among the grass genomes ( salse et al .
2009 ) have also provided a basis for anchoring chromosome ( arm ) specific dna sequences to genetic and physical maps ( mayer et al .
the so - called chromosome zipper approach was developed originally in barley to determine a virtual order of genes using inference of synteny information along the grass genomes ( mayer et al .
incorporation of chromosome arm - specific microarray hybridization information is providing an important cross - reference for the positioning of genes in this framework .
in addition , cross - referencing to bac clones that contain particular genes identified by dna hybridisation helps in ordering bac and fpc contigs .
typically 4,0009,000 genic sequences per chromosome are found for wheat chromosomes , with some likely to represent gene fragments and pseudogenes ( choulet et al .
following their identification , genes conserved between wheat , brachypodium , rice , sorghum , and barley ( hernandez et al .
2012 ) can then be clustered into syntenic groups and , along with dense genetic marker information , used to define an estimated gene order in wheat and barley .
the analysis also identifies predicted genes that may be unique to wheat and barley and thus might be significant in accounting for the specific agronomic attributes of these crops .
high throughput hybridization platforms can be used for anchoring physical maps if arrays of mapped markers are hybridized to labelled pools of bacs ( rustenholz et al .
the hybridization of dna from complex genomes to microarrays with long oligonucleotides that assay different clusters of multiple snps , small deletion / insertion differences , copy number variants , and presence / absence variation in genomic dna rather than single snps have also been used to assay polymorphisms for genotyping ( fu et al .
were hybridised to a barley agilent 15 k expression microarray and allowed 738 barley orthologous genes to be located to their respective bac clones ( rustenholz et al .
the study showed that 68 % of the genes identified in the study were syntenic between wheat chromosome 3b and barley 3h .
early analyses of ribosomal dna loci in the triticeae ( dubcovsky and dvorak 1995 ) indicated that despite a good conservation between the genomes , specific rearrangements occurred .
indications for this conclusion were already evident in bac sequencing and comparison during map - based cloning projects .
more recently , the construction of physical maps and whole chromosome analyses demonstrated that 3040 % of the gene complements in wheat and barley do not reside in the conserved syntenic gene order space ( choulet et al .
rearrangements including deletions and expansions in the genomes of wheat have been frequent ( dubcovsky and dvorak 2007 ; wicker et al . 2011 ) and are considered to be the result of waves of retrotransposable elements movements assumed to have occurred in the recent evolutionary history of wheat ( charles et al . 2008 ; choulet et al .
in the case of the rdna loci in the triticeae , a further variable includes amplification events that increase the number of tandem copies of the genes at a given locus ( dubcovsky and dvorak 1995 ) .
( 2011 ) include the repair of double - strand breaks in dna which can include a dna segment ( plus or minus a gene sequence ) from elsewhere in the genome .
( 2011 ) argued that pseudogenes mostly arise from genome rearrangements , unique gene - domain fusions have been reported to be important in generating a gene that confers temperature - dependent resistance to wheat stripe rust wheat ( fu et al .
protein kinase domains were fused with domains that could be recognized as being important in disease resistance gene networks .
( 2011 ) in an analysis of the short arm of chromosome 1d ( 1ds ) which exists as a ditelosomic chromosome in a standard genetic stock of wheat used for chromosome sorting .
gene sequences for 1ds were assigned to two regions of brachypodium chromosome 2 , syntenic regions 1s and 1l , even though these brachypodium regions are clearly differentiated when alignments with gene sequences from the ditelosomics 1as , 1bs and 1al , 1bl are carried out .
in addition , the wheat ests mapping to the proximal region of 1ds in independent studies were also missing from the ditelo 1ds sequence dataset ( wicker et al . 2011 ) .
in addition to providing the basis for analyzing conserved gene orders on a large scale ( as described earlier ) , comparative genomics has been important in wheat and barley to define conserved features of genes , and several examples are now available for the identification of candidate genes for the phenotypes being studied .
the characterization of the vrn genes in wheat and barley ( yan et al . 2003 , 2004 , 2006 ; yoshida et al . 2010 ) was facilitated by comparative analyses across wheat , barley , and rice .
the importance of modifications in intron 1 for variation in expression of the vrn genes was established through the analysis of allelic variants . a comparison to variants in lolium perenne ( asp et al .
2011 ) showed that indels in several different locations within intron 1 could modify vrn1 expression .
additional examples include the identification of the bract suppression gene trd1 , a gata transcription factor , on barley 1h through fine mapping and anchoring of the phenotype to a syntenic region in rice ( houston et al .
2012 ) , the boron toxicity tolerance gene on barley 4h ( sutton et al . 2007 ) , the rht - d1 gene region on 4d ( duan et al . 2012 ) , and the nac transcription factor on wheat 6b ( distelfeld et al .
, the functional attributes appeared to be quite different in rice and wheat ( distelfeld et al .
2012 ) and indicated extrapolating function based on shared dna sequence structure may not always be possible .
the unique features of the triticeae genomes emphasize the importance of high - resolution mapping populations and physical maps developed in the target species to enable the de novo identification of genes that are unique to wheat and barley biology , as well as genes underlying qtls . as genes and gene regions of interest
2012 ) provides a valuable methodology for identifying new alleles in related varieties or wild relatives .
the recent progress in high throughput marker development combined with new association genetics panels , physical maps , and survey sequences represent a breakthrough in map - based cloning in the triticeae . in wheat , physical maps of chromosome 1a , 1b , 3a , 3b , and 3d ( http://urgi.versailles.inra.fr/gb2/gbrowse/wheat_phys_pub/ ) as well as survey sequences of all 21 individual bread wheat chromosomes are already available on line ( http://urgi.versailles.inra.fr/species/wheat/sequence-repository ) . in barley , a physical map , survey sequences of sorted chromosomes , several thousand of shotgun sequenced bac clones and whole genome shotgun sequence assemblies were integrated to a physical / genetic genome scaffold providing an excellent template for accelerated map - based cloning and comparative genome - based candidate gene identification ( ibsc 2012 ) ( http://mips.helmholtz-muenchen.de/plant/triticeae/barleydisclaimer.jsp ; http://webblast.ipk-gatersleben.de/barley ) . as an example , in the triticeae more than 15 gene and qtl projects are benefiting already from access to these resources ( table 1 ) and , since the reference sequence of chromosome 3b is underway , 343 scaffolds accounting for 29 mb targeting 74 bac - contigs sequences have already been provided to laboratories worldwide . once candidate genes are identified , functional validation is needed to ascertain the function of the candidate . both reverse and forward genetics approaches are now well established for wheat and barley .
stable ( agrobacterium , biolistic ) and transient ( vigs ) transformation systems are performed routinely in many laboratories worldwide , and mutagenized collections have been produced in both wheat and barley . in wheat , several mutant populations have been produced in diploid , tetraploid , and hexaploid genetics backgrounds , and projects are underway to establish tilling by sequencing ( tsai et al .
tilling resources have been established ( caldwell et al . 2004 ; talam et al .
2009 ) that show a wide range in phenotype diversity for the discovery of genes contributing to the complex networks that underpin plant phenotypes . in parallel ,
natural allelic variation can also be explored by ecotilling approaches and associated to phenotypic variation ( xia et al .
2012).table 1examples of gene and qtl projects benefiting from the access to wheat and barley physical maps and sequenceslocustraitchromosomespeciesorganizationpiuse of physical map / sequence informationyrh52stripe rust resistance1bsemmer wheatuniversity of haifa- israelt .
fahima2 physical non - overlapping contigs identified ( total of 3.7 mb with estimated gap of 0.4 mb)pv - qtlfiber content ( qtl)1blbread wheatinra - francej .
salse1 physical map contig ( 645 kb ) anchored to co - segregating cos cg markerqsng.sfrglume blotch resistance ( qtl)3bsbread wheatuniversity of zurich switzerlandb .
tuberosaregion < 200 kb in the physical map containing 4 candidate genessr2stem rust resistance3bsbread wheatcsiro and murdoch universityw .
spielmeyer1 sequenced contig ( 1.26 mb ) spanning the sr2 genetic intervalsv2leaf rust resistance3bsbread wheatinta - argentinamj .
dieguez2 sequenced contigs ( 1 , 2 , and 3 mb ) identified with flanking markers used for marker development , screening of bac library from resistant cultivar and candidate gene identificationsst1solid stem ( saw fly resistance)3bdurum wheatuniversity of saskatchewan canadac .
pozniak17 sequenced contigs identified for marker development , 8 new cosegrating markers developedqft-3bflowering time ( qtl)3bsbread wheatieb - czech republicj . safar38 sequenced contigs identified for marker developmentqcrs.cpi-3bcrown rot ( qtl)3bsbread wheatcsiro australiac .
feuillet9 sequence contigs identified for marker development and candidate gene identificationyr49yellow rust resistance3dsbread wheatcsiro australiaw .
spielmeyercontig at the proximal side identified , contig at distal side not identified yet , and cosegregating contig identifiedcul4tillering3hbarleyuniversity of milan italyl .
rossinione bac spanning the cul4 genetic interval and candidate gene identified and sequenced examples of gene and qtl projects benefiting from the access to wheat and barley physical maps and sequences in table 1 , a summary is provided for traits and their respective genes that have been defined in wheat and barley .
the table focuses on a list of genes on the group 1 and 3 chromosomes in wheat and barley . at a broader level , in addition to identifying the genes for disease resistance , grain quality traits have also been well defined at the dna level .
examples include the low and high molecular weight glutenin subunit loci on the group 1 chromosomes important for flour processing quality , and the ha locus on 5d defining the soft / hard attributes of the grain ( chantret et al .
increased density of markers along genetic and physical maps using array - based techniques for genes and insertion sequence - based polymorphism markers as well as gbs in wheat and barley enable breeders to perform accurate association mapping studies ( heffner et al .
association genetics has only been recently applied to crop plants , ( mackay and powell 2007 ) yet it is an exciting alternative to conventional qtl mapping in bi - parental crosses .
it draws on the principle that linkage disequilibrium ( ld ) tends to be maintained over many generations between loci which are physically linked to one another .
panels of non - related lines represent many cycles of historical recombinations compared to typical qtl mapping populations .
ld will likely decay very rapidly with genetic distance if the panel used consists of very diverse lines ; thus , correlations between marker and qtl will be identified only if the marker is tightly linked to the qtl ( paux et al .
the number of markers needed to accomplish such studies therefore increases with the diversity of the panel , and a balance must be found between the resolution of the panel and the power to detect associations .
barley and wheat can now rely on the genomics tools described above to develop large quantities of molecular markers .
however , to take the full advantage of these resources , it is essential that adapted association panels are developed . in the past years , several elite panels have been developed for wheat and barley , notably for european germplasm .
( 2011 ) described a panel of 195 french - grown elite winter wheat varieties .
2011 ) used a 455 central european winter wheat varieties panel for association mapping of qtl for grain yield , heading date and fusarium head blight resistance , while cockram et al .
( 2010 ) studied a 500 barley cultivar panel for 15 morphological traits . in the triticeaegenome project ,
breeders from france , the uk , and germany established a panel of 376 varieties based on ( 1 ) general phenotypic levels of adaptation to field conditions , ( 2 ) phenotypic homogeneity , and ( 3 ) genotypic diversity .
this panel has been used for genotyping and phenotyping adaptive traits such as yield , heading date , and plant height .
it has been distributed to colleagues in india and argentina who are interested in identifying new alleles in european winter wheat and is accessible for further collaboration .
thus , most of the material currently grown in europe for wheat and barley is represented in one panel or another .
( 2011 ) are complementary resources to investigate traits in western and central european wheat germplasm that could be used to cross - validate qtl regions .
2011 ) identified qtl underlying grain yield on chromosomes 1b , 1d , 2a , 4a , 4d , 5a , 5b , and 7a and heading date on chromosomes 1b , 2b , 4b , 4d , 5a , 5d , and 7d .
moreover , the potential favorable alleles identified in these panels are more likely to be taken up by breeders as they will be already available in elite germplasm and more amenable for introduction into marker - assisted recurrent selection .
finally , genomic selection ( gs ) has been proposed as an alternative to use marker data in breeding that could correct some of the deficiencies in classical marker - assisted selection ( meuwissen 2009 ) and is the subject of further development in crop plants ( heffner et al .
the triticeaegenome panel ( 376 individuals ) represents a good example of the diversity in west european wheat , and it could be used to study gs in wheat .
indeed , the size of the triticeaegenome panel is sufficient to be divided into a training set and a validation set , and phenotypic data have already been gathered over 2 years in a total of seven locations .
the panel itself is not linked to any commercial breeding programme , so it can be envisaged that both researchers and breeders use the resource .
the triticeae community established a unique database , graingenes ( http://wheat.pw.usda.gov/ ) , to provide a suite of services for the triticeae and oat communities , including databases , documents , tools , data files , announcements , curation , and community assistance . to date , graingenes stores 76 wheat genetic maps , more than 100,000 genetic markers , and approximately 271,000 wheat ests .
these sequences can be searched through a blast server or by using queries to get additional information on genetic mapping data .
graingenes also hosts the triticeae repeat databank that comprises 1,717 sequences of wheat transposable elements .
another database , harvest ( http://harvest.ucr.edu/ ) that is highly frequented by users of the triticeae community provides access to curated est assemblies of wheat and barley as well as meta data linking to marker resources and orthologs of related grasses ( close et al . 2008 ) . with the developments in physical mapping and sequencing activities ,
for example , the inra urgi wheat database ( http://urgi.versailles.inra.fr/species/wheat ) provides access to the physical maps of the triticeaegenome chromosome 1bl , 1as , 3b , and 3d as well as to the 3a physical map which is hosted at the wggrc .
chinese spring chromosomes that are constructed under the framework of the iwgsc are being integrated regularly into the database ( http://www.wheatgenome.org/projects/iwgsc-bread-wheat-projects/physical-mapping/ ) .
a gbrowse displays the physical maps in relation with other datasets ( e.g. , genetic markers , reference sequences , qtls , and snps ) . to date , the database stores 26 wheat genetic maps , 19,029 markers , 324 qtls , 10,819 snps , and 544,529 ests .
in addition , urgi hosts the iwgsc sequence repository that provides access to the survey sequence assemblies of the 21 chromosomes of chinese spring ( http://urgi.versailles.inra.fr/species/wheat/sequence-repository ) .
the urgi database is mirrored at the mips which host equivalent datasets for the barley genome ( http://mips.helmholtz-muenchen.de/plant/barley/index.jsp ) . in support of the international efforts to obtain reference sequences from rice ( ricegaas ; http://ricegaas.dna.affrc.go.jp/ ) and the triticeae , a versatile , easy - to - use online automated tool for annotation ,
a semi - automated annotation pipeline called triannot has been developed ( leroy et al . 2012 ) .
its modular architecture allows for the annotation and masking of transposable elements , the structural and functional annotation of protein - coding genes with an evidence - based quality indexing , and the identification of conserved non - coding sequences and molecular markers . to date , the triannot pipeline is parallelized on a 712 cpu computing cluster that can run a 1-gb sequence annotation in less than 26 h. when evaluated on rice and wheat data sets , triannot systematically showed a higher level of reliability than other annotation pipelines that are not improved for wheat .
as it is easily adaptable to the annotation of other plant genomes , triannot should become a useful resource for the annotation of large and complex genomes in the future .
the rapid advances in wheat and barley provide the basis for the next steps in the efficient exploitation of the newly available resources for research and breeding .
the international consortia discussed in this review have been successful in establishing an interface of cooperation to facilitate the exchange of genome sequence data and to increase the impact of advances on growers and breeding programs .
emerging technological advances in physical and genetic mapping , marker development and association genetics , bioinformatics and map - based cloning provide a foundation for step changes in germplasm development that would otherwise take a much longer period of time . | the genomic resources of small grain cereals that include some of the most important crop species such as wheat , barley , and rye are attaining a level of completion that now is contributing to new structural and functional studies as well as refining molecular marker development and mapping strategies for increasing the efficiency of breeding processes .
the integration of new efforts to obtain reference sequences in bread wheat and barley , in particular , is accelerating the acquisition and interpretation of genome - level analyses in both of these major crops . |
when off - resonant , circularly - polarized light propagates through an atomic vapor cell , the vapor can experiences a virtual magnetic field which points the propagating direction of the laser@xcite . with the development of hybrid optical pumping ,
the atomic vapor cell is filled with two or more spin species@xcite .
one of the spin species is directly pumped by laser beam and others are polarized by spin exchange collision . in an atomic co - magnetometer based on k - rb-@xmath0ne , the 770 nm pump laser which is used to directly pump the k atom spins causes the ac stark shift of the rb spins at d2 line@xcite .
we find that the ac stark shift of k atoms could mixes together with the rb shift through spin exchange collision@xcite .
the spin exchange interaction between pair of alkali metal is so large that the pair of alkali metal exchange their spins rapidly .
ac stark shift is always a systematic error in atomic sensors .
for example , in an atomic co - magnetometer based on k - rb-@xmath0ne , the pumping beam ac stark shift could cause the coupling of the input angular velocities of the x and y axis@xcite . for direct optical pumping that only one species alkali metal is utilized , the ac stark shift can be suppressed by tuning the frequency of laser beam to the absorption peaks@xcite .
a diffusion suppression method is also utilized to reduce the ac stark shift@xcite . however , in an atomic sensors based on hybrid pumping , the ac stark shift could not be suppressed by the two methods .
we find that collision mixing of the k and rb ac stark shifts which can be utilized to suppress the total ac stark shifts in an atomic sensors based on hybrid pumping .
we can control the ac stark shift of k to counteract the shift of rb to reduce the total light shift .
we establish a k - rb-@xmath0ne co - magnetometer to study the collision mixing of the ac stark shifts of k and rb atoms .
the full bloch equations@xcite of the three atom species including the k and rb ac stark shifts are established and solved analytic solutions are derived .
the mixing of the k and rb ac stark shifts is experimentally studied .
this study is based on an k - rb-@xmath0ne atomic co - magnetometer@xcite .
the parameters in the model is based on the co - magnetometer .
suppose that in an alkali vapor cell which is filled with k , rb and @xmath0ne gas atoms , the density ratio of k to rb is @xmath1 which is on the order of 0.01 .
@xmath2 and @xmath3 are respectively the densities of k and rb .
k atoms are directly pumped by the d1 line laser and rb atoms are pumped through spin exchange with k atoms . if the frequency of the laser beam @xmath4 is tuned away from the absorption center of the pressure@xcite and power broadened@xcite d1 absorption line , there will be ac stark shift of k @xmath5 in the light propagation direction .
we denote the light propagation direction is the z direction . for rb atoms ,
the far off - resonant laser will cause ac stark shift @xmath6 on the d2 line of rb atoms .
we will show that the two ac stark shifts will mix together through the spin exchange interaction .
rb atoms are polarized by k atoms through spin exchange interaction .
the spin exchange interaction conserve the total angular momentum and exchange the direction of the k and rb spins .
the spin transfer rate of rb to k is given by @xmath7 , where @xmath8 is the spin exchange cross section between rb and k@xcite , @xmath9 is the relative velocity between rb and k. we can calculate the spin transfer rate of k to rb to be @xmath10 . in a k - rb-@xmath0ne co - magnetometer , the temperature of the vapor cell is about 473k and the density of the optically thick rb atoms is about 5@xmath1110@xmath12/@xmath13
. the spin transfer rate of rb to k is calculated to be approximately 1@xmath1110@xmath14sec@xmath15 .
the rb and k atoms are in rapid spin exchange that the ac stark shifts of them mix together .
the mixing of the ac stark shifts is tested by the co - magnetometer .
the bloch equations which are utilized to model the co - magnetometer have been developed to describe the k-@xmath16he co - magnetometer@xcite . in order to model the mixing of the ac stark shifts , we add the equation which is utilized to describe k to the equation group .
the full bloch equations are given by : @xmath17 in the above equations , @xmath18 , @xmath19 and @xmath20 are respectively the polarization of k , rb and @xmath0ne atoms .
@xmath21 is the input rotation velocity .
@xmath22 is the slow down factor due to the rapid spin exchange@xcite .
traditionally , due to the difference of the k and rb nuclear spin , the slow down factor is different for k and rb .
however , the rapid spin exchange between the k and rb spin can change the slow down factor of both k and rb atoms .
the slow down factors will be the same as they collision with each other .
@xmath23 is the external magnetic field .
@xmath24 is a magnetic field which is produced by the @xmath0ne atoms through spin exchange interaction@xcite .
@xmath25 is equal to @xmath26 where @xmath27 is a spin exchange enhancement factor due to the overlap of k electron wave function and the @xmath0ne nucleus .
@xmath28 is equal to @xmath29 , where @xmath30is the nuclear magnetic moment and @xmath31 is the density of @xmath0ne atoms . @xmath32 and @xmath33 are the ac stark shifts of the k atoms and rb atoms .
@xmath34 is the pumping rate of k atoms while @xmath35 gives its direction and magnitude of the photon spin polarization .
@xmath36 is the spin exchange transfer rate from rb atoms to k atoms . in k - rb-@xmath0ne co - magnetometer
, the spin relaxation rate of rb atoms mainly comes from the spin destruction rate between the rb and rb atoms @xmath37 and the spin exchange relaxation rate of rb atoms @xmath38 which is caused by the rb magnetization field@xcite . due to the large density ratio between rb and k , the magnetic field produced by
the electron spins @xmath39 which is experienced by the @xmath0ne spins mainly comes from the rb atoms spins .
@xmath40 is the spin exchange transfer rate from rb to @xmath0ne atoms . @xmath41 and @xmath42 are respectively transverse and longitude relaxation rate of the @xmath0ne atomic spins .
after hours of spin exchange optical pumping of the @xmath0ne spins .
the polarization of @xmath0ne is in its steady state .
suppose that @xmath43 magnetic field and @xmath44 magnetic fields are applied to the co - magnetometer .
the ac stark shifts of k and rb are in the z direction .
suppose that small @xmath43 is applied to the co - magnetometer that the angle between the polarization of the spins and the z direction are small .
the polarization of k , rb and @xmath0ne in the z direction are constants . at the steady state
, it is clear that @xmath45 , @xmath46 and @xmath47 .
the polarization in the z direction could be easily calculated to be : @xmath48 as the density ratio of k to rb is kept at a low level which is about 0.01 in our experiment to improve the uniformity of the rb polarization@xcite .
k and rb atoms are in fast spin exchange and the exchange rate is at the order of 1@xmath1110@xmath49 sec@xmath15 .
the pumping rate of k @xmath34 is kept to be approximately @xmath50 to achieve the condition of 50@xmath51 polarization of rb atoms . according to the conditions in a k - rb-@xmath0ne co - magnetometer ,
@xmath34 is approximately on the order of 1@xmath1110@xmath52 sec@xmath15 .
according to the above discussion , the conditions in equation [ equation2 ] are realized .
a probe beam is used to detect the projection of electron spin polarization along the propagation direction(x direction ) .
rb d1 or rb lines are utilized to detect the polarization .
the polarization of k and rb in the x direction could be solved and is given by : @xmath53 the polarization of rb is measured in the k - rb-@xmath0ne co - magnetometer .
there is a total ac stark shift @xmath54 in equation [ equation3 ] as we measure polarization of rb .
the ac stark shift of k @xmath55 is suppressed by a factor @xmath56 will be measured by the rb polarization .
we say that the light shifts of k and rb are mixed by the spin exchange interaction .
a @xmath43 modulation method could be utilized to measure the mixed ac stark shifts@xcite .
a square @xmath43 magnetic field is applied to the co - magnetometer and the steady state square wave response amplitudes are measured as @xmath57 is changed .
the details of the measurement is shown in the next section .
a k - rb-@xmath0ne co - magnetometer is constructed to measure the mixing of the k and rb ac stark shifts .
the apparatus is similar to the one shown in this reference@xcite .
we just show some main features of the apparatus .
the co - magnetometer consists of a 1.4 cm diameter spherical aluminosilicate glass ( schott8436 glass ) vapor cell that contains a small droplet of k - rb ( @xmath58rb ( 72.2@xmath51 ) and @xmath59rb ( 27.8@xmath51 ) ) mixture , about 3.0atm of @xmath0ne gas ( 70@xmath51 isotope enriched ) and 40 torr of n@xmath60 gas for quenching .
the cell is heated to be 473 k and the oven was in vacuum for thermal insulation .
water cooling system is utilized to protect the magnetic shields from the thermal radiation of the oven .
@xmath61-metal magnetic field shields and ferrit are utilized to shield the earth magnetic field .
the residual magnetic field in the shields is further compensated by a three axis coil .
k atoms are directly polarized by pumping light whose wavelength is on d1 line of k atoms . the pump distributed bragg reflector(dbr ) laser is amplified by a taper amplifier(ta ) to about 1w .
the power density of the pumping light before the vapor cell is set to be about 620mw/@xmath62 .
a polarization beam splitter(pbs ) and a 1/4 wave plate are combined to change the pump light to circular polarized photons .
the probe distributed feedback(dfb ) laser is tuned about 0.3 nm away from the absorption center of the rb d1 line .
both of the vertical pump beam and the horizon probe beam are expanded by beam expanders(be ) .
the photo elastic modulation ( pem ) technique with two high distinction ratio glan - thompson polarizers(gt ) is utilized to measure the rotation of the polarization plane of the linear polarized light .
the laser intensity is accepted by the photo detector(pd ) and amplified by the lock - in amplifier .
the schematic of the experimental setup is shown in figure [ figure1 ] the schematic of the experimental setup.,width=226,height=226 ] we can measure the mixed ac stark shifts @xmath54 in equation [ equation3 ] in the co - magnetometer .
suppose that a step magnetic field @xmath63 in the y direction is applied to the co - magnetometer
. then there will be a step signal of @xmath64 which is directly detected by the probe laser .
we take the derivative of @xmath65 in equation [ equation3 ] and we can get : @xmath66 as a square magnetic field @xmath63 is applied to the co - magnetometer , the steady state output response @xmath64 is measured .
the above measurement is repeated as the magnetic field in the z direction @xmath44 is changed .
as the compensation magnetic field @xmath57 is changed , according to equation [ equation4 ] , the response of the rb polarization in x direction @xmath64 changes as a lorentz function .
due to the existence of the ac stark shifts , the symmetry lorentz function changes into asymmetry one .
[ figure2 ] shows the measured relationship between the compensation field and the modulation response . as we change the wavelength of the pump laser , the symmetry of the lorentz function change .
the fitted results could be used to get the total ac stark shift @xmath67 .
we just show parts of the measured data for it is hard to see the results clearly if all the data is plot in one figure .
the relationship between the compensation field and the modulation response for different pumping wavelength .
the measured data are fitted to equation [ equation4 ] to get the total ac stark shifts.,width=302,height=226 ] fig .
[ figure3 ] shows the relationship between the total ac stark shift and the pump laser frequency detune .
the x axis unit is changed from nm into ghz .
the frequency at 0 ghz is at the 770.108 nm which is the absorption peak of the d1 line of k atoms as there is no broadening of the line .
as we change the frequency of the pumping laser , the ac stark shifts of k atoms is due to virtual transitions@xcite and it is given by : @xmath68 where @xmath69 is the photon number flux and @xmath70 is the transverse area of the pumping light .
@xmath71 is the electron radius and @xmath72 is the velocity of light .
@xmath73 is the oscillator strength@xcite and @xmath74 is the electron gyro - magnetic ratio .
@xmath75 is the line width of the pressure and power broadened absorption line of k d1 line with the 3atm @xmath0ne atoms@xcite .
@xmath76 is the absorption center of the absorption line .
the absorption center is not at 770.108 nm and it is shifted by the collision with noble gas@xcite .
the far off - resonant pumping laser will cause ac stark shift of rb atoms on the d2 line . due to the large detune of the laser which is much larger than the pressure broadened absorption line width of rb-@xmath0ne pair ,
the ac stark shift of rb can be simplified to be : @xmath77 as we change the pumping laser frequency , the ac stark shift of rb is approximately constant . combining equation[equation5 ] with equation[equation6 ] , we fit the total ac stark shift @xmath78 with the measured data in fig .
[ figure3 ] .
we can conclude that the total ac stark shift which is measured by the rb polarization in the x direction is the mixing of the rb and k ac stark shifts and the k ac stark shift is suppressed by a factor of @xmath56 .
the relationship between pumping laser frequencies and the total ac stark shifts which are measured by the co - magnetometer.,width=302,height=226 ]
the line width of the lorentz function in fig . [ figure3 ] is fitted to be 30.6ghz .
theoretical calculation result shows that the pressure broadened line width of k in 3.0atm @xmath0ne is 23.4ghz@xcite .
the laser power used in this experiment is high .
the power broadening of the absorption line can not be neglected .
the total line width of the pressure broadening and power broadening@xcite is given by : @xmath79 where @xmath80 is the broadening line width due to pressure broadening .
@xmath81 is the saturation intensity which is equal to @xmath82 . here
@xmath83 is the lifetime for radiative broadening .
the resonance transition of k is 770.108 nm and the radiative broadening in the 3atm vapor cell is 23.4ghz .
these lead to an intensity @xmath81=1.0w/@xmath62 .
the power density is 620mw/@xmath62 and the total broadening of the line is 29.4ghz .
this is coincident with the fitted result of 30.6ghz .
there is an constant 4.7nt in the fitting .
the constant is the ac stark shift of rb .
the ac stark shift of rb is calculated to be 4.5nt as the pumping power density is 620mw/@xmath62 .
this is coincident with the measured result of 4.7nt .
we can also get the density ratio of k to rb to be 0.0037 .
the ac stark shift could be further suppressed by change the vapor cell to a larger density ratio of k to rb .
the mixing of the ac stark shift of two alkali metal ensembles is closing related to the density ratio of the two ensemble .
if the density ratio is large , we need to tune the laser wavelength far away from the resonance center of the absorption line to compensate the ac stark shift of the other ensemble .
this could lead to reduction of pumping rate .
one need to use vapor cells with small density ratio to avoid this problem . on the other hand
, we could use two spin ensembles whose wavelengths are far away from each other .
the cs - rb pair could be utilized to compensate the ac stark shift .
the pumping cs d1 line is at 894 nm which is far away from the 795 nm rb d1 line .
the ac stark shift which needs to be compensate is relatively small compared to the k - rb pair .
we only need to tune small wavelength away from the absorption center .
in conclusion , we find the mixing of k and rb ac stark shifts through rapid spin exchange collision .
the spin exchange collision between them rapidly change the direction of the spin and conserve the total angular momentum .
the k ac stark shift is suppressed by a factor of @xmath56 which is the density ratio between k and rb . as ac stark shift is always a systematic error in precision measurement . with this finding
, we can get rid of ac stark shift by compensating the ac stark shift of one alkali atom with the other .
this work is supported by the key programs of national natural science foundation of china under grant no . 61227902 , 61374210 and 863 plan of china .
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a 39 ( 11 ) , 5613 ( 1989 ) . | in a hybrid pumping alkali vapor cell that both k and rb are filled , k atom spins are optically pumped by laser and rb atom spins are polarized by the k spins through spin exchange .
we find that the ac stark shift of the rb atoms is composed of not only the ac stark shift of the rb atoms caused by the far off resonant pumping laser which is tuned to the k absorption lines , but also the ac stark shift of the k atom spins .
the mixing of the light shifts through fast spin exchange between k and rb atoms are studied in this paper and we demonstrate a k - rb-@xmath0ne co - magnetometer in which the ac stark shift of the rb atoms are reduced by the collision mixing . |
the demand for higher photovoltaic energy conversion efficiencies has recently led to the emergence of a whole new generation of solar cell concepts based on multiple junctions @xcite , intermediate bands @xcite , multiple exciton generation @xcite or hot carrier effects @xcite .
compared to the standard bulk technology , the corresponding devices are of highly increased structural and conceptual complexity , comparable to the advanced optoelectronic devices in the field of light emission , such as solid state lasers and light emitting diodes , and like these counterparts , they strongly rely on the design degrees of freedom offered by the utilization of semiconductor nanostructures .
this instance is hardly surprising if one considers that photovoltaics ( `` photons in - electrons out '' ) can be regarded as the inverse regime of solid state lighting ( `` electrons in - photons out '' ) .
however , even though the structures be the same , in switching to the photovoltaic operation , the focus is shifted from the optical to the electronic output characteristics , with the objective to achieve maximum carrier extraction rate at largest possible separation of contact fermi levels . while there is still a relation between photovoltaic and light - emitting quantum efficiency through the optoelectronic reciprocity relation @xcite , real devices are
usually non - radiatively limited , and efficient charge transport from the location of photogeneration to and fast extraction at the contacts becomes thus of pivotal importance .
indeed , the semiconductor nanostructures not only have to provide tunable and localization enhanced optical transitions ( photogeneration ) , but their absorbing states need either be coupled to extended bulk - like states or among themselves in order to enable electronic current flow ( charge separation ) .
the coupling can be provided via hybridization in situations where carriers can tunnel between localized and extended states , as in the case of ( multi ) quantum well diodes , or via inelastic scattering processes such as absorption and emission of phonons or low energy photons , respectively .
the former mechanism is important both in devices relying on thermionic emission , such as multi - quantum - well solar cells @xcite , as well as in superlattice absorber devices in the sequential tunneling transport regime @xcite .
the latter mechanism is utilized in the intermediate band solar cell , where the carriers from the isolated intermediate absorber band are excited into the contacted continuum via an additional photon absorption process .
apart from providing coupling mechanisms , non - radiative inelastic scattering mechanisms are also responsible for any non - radiative output power losses in the transport process , either via recombination of charge carriers or via energy dissipation due to charge carrier thermalization and relaxation . a substantial reduction of this energy dissipation forms the basis of the hot carrier solar cell concept , which on the other hand requires the use of energy selective contacts to extract the hot carriers .
again , the application of semiconductor nanostructures is being considered , e.g. resonant tunneling through single quantum dots @xcite .
this is an example of a purely electronic use of nanostructures in solar cells , independent of the optical properties .
another example would be the interband tunnel contact in multi - junction devices @xcite .
the opposite situation of purely optical functionality concerns the vast field of light management in solar cells via photonic structures , which lies beyond the scope of this review . as a result of the large number of implications that are linked to the use of nanostructures in photovoltaic devices
, it is very hard to say whether a certain structure is going to be beneficial or detrimental to the device characteristics , even under the idealized conditions of the radiative limit , assuming defect - free interfaces etc . in many devices
, there is for instance the intrinsic conflict mentioned above between maximum localization needed for ideal absorption and maximum delocalization required for ideal transport .
indeed , at this stage , only a few of the high - efficiency concepts have been realized successfully , such as the iii - v semiconductor material based multi - junction devices and strain - balanced multi - quantum - well solar cells , the latter example demonstrating in an impressive way the feasibility of highly efficient nanostructure based devices with a large number of interfaces . in order to be able to asses the potentials and capabilities of the various novel photovoltaic concepts ,
a realistic theoretical estimate of the specific device characteristics is thus highly desirable .
the complexity of structure and physical mechanisms as well as the prominent role of dimensional and quantum effects characterizing the operation of these novel solar cell devices preclude the use of standard macroscopic bulk semiconductor transport theory conventionally used in photovoltaics , which is nothing else than the charge continuity equation for electrons and holes with a source term corresponding to the net interband generation rate and a drift - diffusion current with a longitudinal electric field obeying poisson s equation .
on the other hand , rate equation type quantum optical approaches used for solid state lasers or light - emitting diodes often lack a satisfactory description of dissipative charge transport and extraction / injection at contacts , while suitable quantum transport formalisms were devised for unipolar devices and do thus normally not include the optical coupling . hence , for a comprehensive theoretical description of photovoltaic devices based on nanostructured absorbers and/or conductors , a theory is required that treats on equal footing both quantum optics and dissipative quantum transport .
these requirements can only be satisfied on the level of quantum kinetics , such as provided by the wigner - function , density - matrix and non - equilibrium green s function formalisms . among the quantum - kinetic theories ,
the non - equilibrium green s function ( negf ) method is the most versatile and powerful tool to study non - equilibrium properties of nanostructures , since it is based on a quantum field theoretical approach to non - equilibrium statistical mechanics @xcite . in the negf approach ,
the green s functions ( gfs ) for the involved ( quasi)particles ( electrons , holes , phonons , photons , excitons , plasmons , etc ) are the model functions providing the physical quantities that characterize the system .
they correspond to the response of the system to external perturbations , the latter entering the equations of motion for the green s functions , the dyson s equations , in the form of self - energies .
the self - energies due to ( weak ) interactions such as electron - phonon or electron - photon coupling are calculated using standard diagrammatic or operator expansion techniques used in many - body perturbation theory @xcite .
the coupling to the environment represented by contacts , i.e. the application of open boundary conditions , is provided by a special type of boundary self - energy . due to the generality of the method steming form its sound foundations
, the negf formalism has found application in the description of large number of different micro- and mesoscopic systems under non - equilibrium conditions , of which only a few can be mentioned here .
apart from the application to actual non - equilibrium quantum transport phenomena comprising ballistic transport and resonant tunneling in semiconductor multilayers and nanostructures of different dimensionality ( quantum wells @xcite , wires @xcite and dots @xcite ) , metallic and molecular conduction @xcite , phonon mediated inelastic and thermal transport @xcite , coulomb - blockade @xcite and kondo - effect @xcite , it is also used to describe strongly non - equilibrium and interacting regimes in semiconductor quantum optics requiring a quantum kinetic approach @xcite , with phenomena such as non - equilibrium absorption , interband polarization , spontaneous emission and laser gain .
the concept was first adapted to the simulation of transport in open nanoscale devices on the example of tunneling in metal - insulator - metal junctions @xcite , and has in the following been applied to investigation and modelling of mosfet@xcite , cnt - fet @xcite , resonant tunneling diodes @xcite and interband tunneling diodes @xcite , interband quantum well lasers @xcite and intraband quantum cascade lasers @xcite , as well as infrared photodetectors @xcite , cnt - photodiodes @xcite and quantum well leds @xcite .
the theory was formulated both for continuum effective - mass @xcite an atomistic multiband tight - binding @xcite models of the electronic structure , and in the case of molecular conduction it is combined with ab - initio methods such as density functional theory @xcite .
this review now provides an overview of the general framework for the theoretical description of quantum photovoltaic ( qpv ) devices based on the negf formalism , as first introduced in @xcite for the investigation of quantum well solar cells ( qwsc ) . after the specification of the type of system under consideration ,
the non - equilibrium quantum statistical treatment of its different physical degrees of freedom ( charge carriers , photons , phonons ) is discussed , resulting in a general microscopic theory of photovoltaic devices .
the unique kind of spectral information the theory is able to provide is then illustrated on the example of two prototypical qpv devices , a single quantum well photodiode and a silicon - oxide based superlattice absorber device .
as in any device simulation , the ultimate goal of the present approach it to predict the response of a device to a given variation in the external conditions ( bias , temperature , illumination , ) and for given material properties ( electronic , phononic , photonic structure ) , via the solution of ( coupled ) dynamical equations for the degrees of freedom of the device affected by the perturbation . in a formalized picture ,
the dynamical equations describe the evolution of the states of the system and their occupation for given initial solution and boundary conditions . before turning to the dynamical equations ,
let us thus briefly discuss the characteristic set - up of the system to be described .
[ sec:1 ] .,width=264 ] .
the bulk leads are absent in the case where the nanostructure states form both absorber and conductor .
the device ( absorber / emitter ) states can be bound , quasi - bound or form a quasi - continuum . at the contacts ,
photogenerated carriers are extracted and thermalized carriers are injected according to the chemical potentials @xmath0 for electrons and holes , respectively . in the device regions ,
the physical processes relevant for the photovoltaic operation are : ( b ) radiative transitions , i.e. ( 1 ) interband photogeneration and radiative recombination as well as ( 2 ) radiative intraband transitions , which may also lead to ( 3 ) photon recycling ; ( c ) coherent and dissipative quantum transport involving non - radiative intraband transitions , such as ( 1 ) phonon mediated carrier capture and escape , ( 2 ) intraband relaxation , ( 3 ) scattering assisted or ( 4 ) direct tunneling between absorber states , and ( 5 ) phonon assisted carrier escape as combination of the two ; ( d ) non - radiative recombination , via ( 1 ) the auger mechanism or ( 2 ) deep trap states .
[ fig : qpv_device_bandscheme],width=302 ] .
the bulk leads are absent in the case where the nanostructure states form both absorber and conductor .
the device ( absorber / emitter ) states can be bound , quasi - bound or form a quasi - continuum . at the contacts ,
photogenerated carriers are extracted and thermalized carriers are injected according to the chemical potentials @xmath0 for electrons and holes , respectively . in the device regions ,
the physical processes relevant for the photovoltaic operation are : ( b ) radiative transitions , i.e. ( 1 ) interband photogeneration and radiative recombination as well as ( 2 ) radiative intraband transitions , which may also lead to ( 3 ) photon recycling ; ( c ) coherent and dissipative quantum transport involving non - radiative intraband transitions , such as ( 1 ) phonon mediated carrier capture and escape , ( 2 ) intraband relaxation , ( 3 ) scattering assisted or ( 4 ) direct tunneling between absorber states , and ( 5 ) phonon assisted carrier escape as combination of the two ; ( d ) non - radiative recombination , via ( 1 ) the auger mechanism or ( 2 ) deep trap states .
[ fig : qpv_device_bandscheme],title="fig:",width=105 ] .
the bulk leads are absent in the case where the nanostructure states form both absorber and conductor .
the device ( absorber / emitter ) states can be bound , quasi - bound or form a quasi - continuum . at the contacts ,
photogenerated carriers are extracted and thermalized carriers are injected according to the chemical potentials @xmath0 for electrons and holes , respectively . in the device regions ,
the physical processes relevant for the photovoltaic operation are : ( b ) radiative transitions , i.e. ( 1 ) interband photogeneration and radiative recombination as well as ( 2 ) radiative intraband transitions , which may also lead to ( 3 ) photon recycling ; ( c ) coherent and dissipative quantum transport involving non - radiative intraband transitions , such as ( 1 ) phonon mediated carrier capture and escape , ( 2 ) intraband relaxation , ( 3 ) scattering assisted or ( 4 ) direct tunneling between absorber states , and ( 5 ) phonon assisted carrier escape as combination of the two ; ( d ) non - radiative recombination , via ( 1 ) the auger mechanism or ( 2 ) deep trap states .
[ fig : qpv_device_bandscheme],title="fig:",width=105 ] .
the bulk leads are absent in the case where the nanostructure states form both absorber and conductor .
the device ( absorber / emitter ) states can be bound , quasi - bound or form a quasi - continuum . at the contacts , photogenerated carriers are extracted and thermalized carriers are injected according to the chemical potentials @xmath0 for electrons and holes , respectively .
in the device regions , the physical processes relevant for the photovoltaic operation are : ( b ) radiative transitions , i.e. ( 1 ) interband photogeneration and radiative recombination as well as ( 2 ) radiative intraband transitions , which may also lead to ( 3 ) photon recycling ; ( c ) coherent and dissipative quantum transport involving non - radiative intraband transitions , such as ( 1 ) phonon mediated carrier capture and escape , ( 2 ) intraband relaxation , ( 3 ) scattering assisted or ( 4 ) direct tunneling between absorber states , and ( 5 ) phonon assisted carrier escape as combination of the two ; ( d ) non - radiative recombination , via ( 1 ) the auger mechanism or ( 2 ) deep trap states .
[ fig : qpv_device_bandscheme],title="fig:",width=105 ] fig .
[ fig : qpv_device_structure ] shows the basic building blocks of a quantum photovoltaic device , which are in essence the same as for a conventional solar cell , namely an ( intrinsic ) absorber with carrier species selective contacts , usually obtained via selective doping resulting in a bipolar junction device .
the difference to the standard configuration is made by the presence of additional nanostructure absorbers in the intrinsic region , leading to the formation of quantum wells , wires or dots and thus exhibiting states with increased degree of localization .
the band diagram along the direction of transport which corresponds to such a device structure is shown schematically in fig .
[ fig : qpv_device_bandscheme](a ) .
the bulk leads are absent in the case where the nanostructure states form both absorber and conductor , i.e. in the case where the nanostructure states are extended in transport direction , as in nanowires or superlattices . at the contacts ,
photogenerated carriers are extracted and thermalized carriers are injected according to the splitting of the chemical potentials @xmath0 of electron and hole reservoirs by the terminal voltage @xmath1 . apart from this functionality , which is common to all electronic devices , there is an aspect of contacts in photovoltaics that is even more essential , which is the mentioned carrier selectivity .
it can be shown that even in absence of built in fields , the existence of carrier selective contacts enables photovoltaic device operation @xcite .
for some photovoltaic applications like the hot carrier solar cell , contacts need in addition be energy selective .
even though most solar cells are rather macroscopic than mesoscopic devices and the transport properties are not primarily determined by the contact resistance , the contacts are usually critical components in the solar cell design .
this is due to electronic matching problems , leading to band offsets , schottky barriers , strong local fields and defect formation .
indeed , defect recombination at contacts represents a major loss mechanism , and large efforts are dedicated to the passivation of these surface defects . while the contact states do normally form a continuum , the absorber states in the device region can range from completely localized bound states to quasibound states or even extended quasicontinuum states , depending on the degree of confinement imposed by the nanostructure , and they enable a large number of additional radiative and non - radiative transitions which are relevant for the photovoltaic device operation , as shown in figs .
[ fig : qpv_device_bandscheme](b)-(d ) . here
, the transitions which do involve only one carrier species and conserve particle number are termed intraband processes , even though they take place between discrete states rather within a proper band or even between subbands .
analogously , transitions across the fundamental gap ar termed interband transitions . in the case of absorber states with reduced extension in transport direction , non - local processes such as direct or scattering assisted tunneling connecting spatially separated states or localized to extended states become pivotal for the device performance , and must thus be considered in any appropriate simulation of such a device . due to the large number of applications of the negf formalism
, its foundations have been discussed in many reviews and books , e.g. @xcite , wherefore we will limit the discussion here to the aspects that are relevant for photovoltaic applications .
many of these aspects are also present in resonant - tunneling devices on the quantum transport side and in light - emitting devices on the quantum optics side , and the discussion thus follows some of the lines of the corresponding literature , such as presented in @xcite and @xcite .
we start the discussion with the quantum - statistical mechanics picture of the semiconductor device .
a comprehensive , unified description of the quantum photovoltaic device is found on the quantum - statistical mechanics level , where the optical , electronic and vibrational degrees of freedom of the system are described by the corresponding quantum fields for photons , charge carriers and phonons .
within the negf theory of quantum optics and transport in excited semiconductor nanostructures , physical quantities are expressed in terms of quantum statistical ensemble averages of single particle operators for the interacting quasiparticles introduced above , namely the fermion field operator @xmath2 for the charge carriers , the quantized vector potential @xmath3 for the transverse photons and the ionic displacement field @xmath4 for the phonons .
the corresponding gfs are @xmath5 ~&\mathrm{(photons)}\label{eq : photgf } \\
\mathcal{d}_{\alpha\beta}^{p}(\tilde{\underbar{1}},\tilde{\underbar{2}})=&-\frac{i}{\hbar } \langle\hat{\mathcal{u}}_{\alpha } ( \tilde{\underbar{1}})\hat{\mathcal{u}}_{\beta}(\tilde{\underbar{2 } } ) \rangle_{\mathcal{c}},~&\mathrm{(phonons ) } \label{eq : phongf } \end{aligned}\ ] ] where @xmath6 denotes the contour ordered operator average peculiar to non - equilibrium quantum statistical mechanics @xcite for arguments @xmath7 with @xmath8 on the keldysh contour @xcite . in the case of the lattice displacement field , the continuous spatial coordinate @xmath9 is replaced by the discrete ion position vectors @xmath10 , where @xmath11 is the equilibrium lattice vector and @xmath12 the basis vector within the unit cell @xcite .
the associated four - vector is @xmath13 .
since it is a declared goal of the present approach to treat systems where any of the degrees of freedom may be quantized to some extent via dimensional confinement , we will keep the treatment as general as possible and thus use the real - space , complex - time representation of the operators and their averages in the review of the formalism , even though in many cases the choice of a reciprocal or modal space reduces formal and computational complexity significantly .
the gfs are determined as the solutions of corresponding dyson s equations @xcite , @xmath14 g(\underbar{3},\underbar{2 } ) & = \delta(\underbar{1}-\underbar{2}),\nonumber\\ \int_{\mathcal{c } } d\underbar{3 } \left[(\overleftrightarrow{\boldsymbol{\mathcal{d}}}_{0}^{\gamma})^{-1}(\underbar{1},\underbar{3 } ) - \overleftrightarrow{\boldsymbol{\pi}}^{\gamma}(\underbar{1},\underbar{3})\right ] \overleftrightarrow{\boldsymbol{\mathcal{d}}}^{\gamma}(\underbar{3},\underbar{2})&= \overleftrightarrow{\boldsymbol{\delta}}(\underbar{1}-\underbar{2}),\nonumber \label{eq : dyson_phot}\\ \int_{\mathcal{c } } d\underbar{3 } \left[(\boldsymbol{\mathcal{d}}_{0}^{p})^{-1}(\tilde{\underbar{1}},\tilde{\underbar{3}})- \boldsymbol{\pi}^{p}(\tilde{\underbar{1}},\tilde{\underbar{3}})\right ] \boldsymbol{\mathcal{d}}^{p}(\tilde{\underbar{3}},\tilde{\underbar{2}})&= \boldsymbol{\delta}(\tilde{\underbar{1}}-\tilde{\underbar{2 } } ) , \end{aligned}\ ] ] where the integration is @xmath15 .
the gfs @xmath16 , @xmath17 and @xmath18 are the propagators for non - interacting electrons , photons and phonons , respectively , @xmath19 denotes transverse and boldface tensorial quantities .
the electronic self - energy @xmath20 encodes the renormalization of the charge carrier gfs due to the interactions with photons and phonons and other carriers , and enables thus the description of charge carrier generation , recombination and relaxation processes .
it is responsible for the appearance of excitonic effects in the carrier spectrum and leads to band - gap renormalization under high excitation .
charge injection and extraction at contacts is considered via an additional boundary self - energy term reflecting the openness of the system .
the photon and phonon self - energy tensors @xmath21 and @xmath22 describe the renormalization of the optical and vibrational excitation modes due to the interaction with the electronic system , i.e. absorption and emission of photons and phonons , leading to phenomena such as photon recycling or hot carrier effects and including excitonic signatures in the bosonic spectra .
the self - energies can be derived either via perturbative methods using a diagrammatic approach or a wick factorization , or using variational derivatives .
their dependence on the gfs can be expressed using hedin s approach @xcite ( henceforth , contour integration over internal variables is assumed ) @xmath23 where @xmath24 , @xmath25 and @xmath26 are the bare interaction vertices . in the expression for the phonon self - energy ,
the rhs is integrated over all continuous spatial coordinates .
the effective carrier - carrier interaction potential @xmath27 is the sum of an electronic plasmon screening and a phonon - mediated contribution , @xmath28 here , @xmath29 is the longitudinal electromagnetic polarization function corresponding to the self - energy of longitudinal photons and obeying the equation @xmath30 and @xmath31 is the density - density correlation function of the nuclei , which is related to the phonon gf in real space via @xcite @xmath32 where @xmath33 is the local charge density due to the ion cores .
the equations for the vertex corrections used in the iterative determination of the self - energies are @xmath34 inserting these expressions in the equations for the polarization functions provides self - consistent approximations for the latter in the form of the bethe - salpeter equation for the scalar four - point polarization function @xmath35 through the relations @xmath36 for practical evaluation , the above equations are rewritten in terms of the real time components of the gfs and self - energies according to the order of the time arguments on the contour @xcite , i.e. the lesser ( @xmath37 ) , greater ( @xmath38 ) , retarded ( r ) and advanced ( a ) components . in photovoltaics ,
in contrast to standard applications of negf in ultra - fast laser physics , but similar to many other quantum transport situations , one is primarily interested in the _ steady - state _
behaviour , and it is thus usually sufficient to consider the dependence on the time difference @xmath39 , which permits a translation of the investigation into the energy domain via the fourier transform @xmath40 in the formulation of the system hamiltonian , a common approach is to partition the system into easily accessible term , with most of the complexity in the remainder . in the present case ,
there are three aspects of complexity that may be tackled by this way , namely 1 .
the openness of the system , i.e. the requirement to include the contacts in the description of the system , 2
. the presence of interactions in the device , and 3 .
the different degrees of freedoms to be considered , i.e. electronic , optical and vibrational .
the first aspect leads to a system hamiltonian partitioning of the form @xmath41 consisting of the separate terms for isolated device , contact reservoir and the coupling between the two . in the second case , the system hamiltonian is written as the sum of non - interacting and interaction terms , @xmath42 finally , we have the different components attributed to electrons , photons and phonons , @xmath43 where the terms include the mutual interactions as well as the interactions with further system components such as impurities etc . in order to make the system treatable , interactions in the contacts
are not considered explicitly , and their effect on the contact - device coupling is neglected , which amounts to the assumption @xmath44 . furthermore , the bosonic subsystems will be regarded as non - interacting , i.e. @xmath45 .
this leaves the total system hamiltonian @xmath46,\\ \hat{h}_{i}^{d}=&\hat{h}_{ee}^{d}+\hat{h}_{e\gamma}^{d}+\hat{h}_{ep}^{d}.\end{aligned}\ ] ] to quantify the action of the hamiltonian on the many - body system , it is represented in second quantization using the field operators introduced in sec.[sec : fieldop ] , e.g. for the electronic system @xmath47 in the case of the carrier - carrier interaction , this produces a two - particle hamiltonian , while all the other terms are on the single - particle level .
the hamiltonian can now be used in the derivation of the equations for the self - energies using the many - body perturbation theoretical expansion of @xmath48 and @xmath49 where the perturbation is given by @xmath50 . by restricting the perturbation to specific parts of the hamiltonian
, the corresponding self - energy terms can be identified in the resulting dyson equation . in the following ,
the hamiltonian terms and corresponding self - energies for the contacts and the various interactions shall be discussed .
[ [ electrons ] ] electrons + + + + + + + + + the electronic system without interactions between valence electrons and coupling to the bosonic degrees of freedom is described by @xmath51 where @xmath52 is the free electron mass . in the above expression ,
the first term provides the kinetic energy and @xmath53 contains the potential for the interaction of valence electrons with the ion cores .
it is further customary to include in @xmath53 also the hartree term of the coulomb interaction corresponding to the solution of poisson s equation that considers carrier - carrier interactions ( @xmath54 ) on a mean - field level .
the gfs corresponding to this hamiltonian is defined via @xmath55g_{0}(1,1')=\delta(1,1'),\ ] ] with the inverse function in given by @xmath56\delta(1,1 ' ) .
\label{eq : inv_carr}\ ] ] the hamiltonian operator in is the one entering the steady - state schrdinger equation corresponding to the single particle eigenvalue problem of the isolated system , @xmath57 in photovoltaic devices , the electronic system is open in at least one dimension @xmath58 , for which thus scattering states have to be used rather than eigenstates of the closed system .
however , the remaining confined dimensions @xmath59 may still be described by the corresponding eigensolutions , allowing for an eigenmode expansion of hamiltonian , gfs and self - energies in these dimensions , which results in a general field operator representation @xmath60 [ [ photons ] ] photons + + + + + + + while absorption in most nanostructured solar cells may be reasonably described by the linear response to a _
coherent _ excitation , spontaneous emission as the most fundamental loss process relies on the coupling to the _ incoherent _ field due to vacuum fluctuations . in general , the total electromagnetic field may thus be written as the superposition @xmath61 of a coherent contribution @xmath62 corresponding to coherent light sources and a contribution @xmath63 with @xmath64 from incoherent light sources and from spontaneous emission .
while the coherent vector potential is related to the time - dependent part of the classical electric field @xmath65 via the standard relation @xmath66 and is thus obtained from the solutions of maxwell s equations according to classical electrodynamics , the incoherent part needs to be treated on the quantum mechanical level via the gf introduced above and will be discussed in what follows . in terms of the vector potential operator introduced at the beginning of this section ,
the hamiltonian of transverse electromagnetic radiation reads @xcite @xmath67.\end{aligned}\ ] ] the free contour - ordered photon gf in real space obeys the equation @xmath68 \overleftrightarrow{\boldsymbol{\mathcal{d}}}_{0}(1,1 ' ) = \overleftrightarrow{\boldsymbol{\delta}}(1,1').\ ] ] which , in analogy to , defines the inverse free photon gf entering the photon dyson equation in via @xmath69\overleftrightarrow{\boldsymbol{\delta}}(1,1').\label{eq : freephotprop}\end{aligned}\ ] ] since it is a solution to the wave equation following from maxwell s equations , the quantized field can be represented as the free - field mode expansion @xmath70\nonumber\\ & \times e^{i{\mathbf q}{\mathbf r}},\label{eq : photfieldop}\\ \mathbf{a}_{0}(\lambda,\mathbf{q})=&\frac{\hbar}{\sqrt{2\epsilon_{0}v\hbar\omega_{\mathbf{q } } } } \boldsymbol{\epsilon}_{\lambda{\mathbf q}},\end{aligned}\ ] ] where @xmath71 is the polarization of the photon with wave vector @xmath72 and energy @xmath73 added to or removed from photon mode @xmath74 by the bosonic creation and annihilation operators @xmath75 and @xmath76 is the volume . in this representation
, the non - interacting hamiltonian of transverse radiation acquires the simple form @xmath77 with the representation , the em gf in can be related to the bare scalar photon gf corresponding to the following expectation value of bosonic operators , @xmath78 via @xmath79 noting that the photon occupation number operator for free field mode @xmath74 is given by @xmath80 , the components of the scalar photon gf can be expressed in the energy domain as @xmath81,\\ \mathcal{d}_{\lambda}^{\gamma , r / a}({\mathbf q};e)&=\frac{1}{e-\hbar\omega_{\lambda,{\mathbf q}}\pm i\eta}-\frac{1}{e+\hbar\omega_{\lambda,{\mathbf q}}\pm i\eta}. \label{eq : equilphoten}\end{aligned}\ ] ] with @xmath82 the mode occupation , which in the free - field case is related to the incident photon flux via @xmath83 the modal photon flux in turn is given by the modal intensity of the em field through @xmath84 .
for normal incidence along @xmath85 @xmath86 and thermal radiation from source at temperature @xmath87 , the occupation can be written @xcite @xmath88 where @xmath89 is the bose - einstein distribution function and @xmath90 is half of the aperture angle under which the source is seen by the solar cell . in the general case of an inhomogeneous medium ,
one may opt to include the modification of the optical mode due to spatially varying background dielectric constant @xmath91 in for the free propagator by replacing @xmath92 by @xmath93 , where @xmath94 . in the waveguide situation ,
the resulting problem gives rise to confined optical modes , which , in analogy to the electronic case , can be used to expand the photon gfs @xcite .
as discussed above , solar cells are optically open in at least one dimension @xmath58 .
the general expression for the photon field operator is thus @xmath95 where @xmath96 are the eigenmodes in the confined dimensions .
[ [ phonons ] ] phonons + + + + + + + in analogy to the photon field , the lattice displacement field for a bulk semiconductor with full translational symmetry can be expanded into vibrational eigenmodes in reciprocal space , @xmath97\nonumber\\ & \times e^{i\mathbf{q}\cdot(\mathbf{l}+\boldsymbol{\kappa})},\label{eq : normalmode}\\ \mathcal{u}_{0,\alpha\boldsymbol{\kappa}}(\lambda,\mathbf{q})= & \frac{\hbar}{\sqrt{2nm_{\boldsymbol{\kappa}}\hbar\omega_{\lambda,\mathbf{q } } } } \boldsymbol{\epsilon}_{\alpha\boldsymbol{\kappa}\lambda}({\mathbf q } ) , \\ & ( \alpha = x , y , z),\nonumber\end{aligned}\ ] ] where @xmath98 is the number of atoms , @xmath99 the mass of the basis atom at @xmath12 , and @xmath100 are the bosonic creation and annihilation operators for a phonon mode @xmath101 with polarization @xmath102 and energy @xmath103 determining the time - evolution in complete analogy to .
the phonon modes of a given structure follow from the eigenvalue equation @xmath104 in terms of the dynamical matrix @xmath105 , which in turn is determined by the interatomic force constants @xmath106 via @xmath107 the interatomic force constants can be obtained via phenomenological models or ab - initio calculations @xcite .
again , it is possible to express the hamiltonian and gf of the displacement field given in in terms of the vibrational eigenmodes , the former acquiring the form @xmath108 and in the case of the latter via the bare scalar bosonic propagator @xmath109 through the relation @xmath110 in the case of coupling to equilibrium phonons , the scalar propagator can be expressed in a form similar to eq .
, with the occupation @xmath111 given by the bose - einstein distribution at the temperature of the heat bath
. in the case of broken translational invariance caused by the use of nanostructures , the size of the eigenvalue problem in will increase by the dimension of the unit cell in the direction of aperiodicity , while the dimension of the reciprocal space is correspondingly reduced .
however , the system is not elastically open in the sense that a scattering problem needs to be solved , i.e. , the vibrational state can be described in terms of vibrational eigenmodes in all dimensions . in theory
, contacts represent the open boundary conditions that need to be imposed on an open system in contact with the environment in order to enable charge exchange between the device and the reservoir formed by the contact . in macroscopic theories ,
boundary conditions are applied to the carrier density : surface charge is either zero in the case of ohmic contacts ( local charge neutrality ) or fixed by the schottky barrier height in the case of metal - semiconductor contacts . in microscopic transport theories , the description of contacts to open systems is itself a whole field of ongoing research . at the most basic level
, the formalism is required to provide information about the density of states in the contact , the occupation of these states , and the coupling of the contact states to the states in the device . in the negf formalism , all this information is contained in the boundary or contact self - energy .
in the electronic case , the general treatment ( see e.g. @xcite ) starts from the partitioning of the overall gfs into contact and device contributions , according to the overall hamiltonian in ( in a discrete basis ) @xmath112 where @xmath113 .
is identical to the dyson equation produced by a first order perturbation in the contact - device hamiltonian , i.e. using @xmath114 in .
if written out in components , it can be used to obtain the retarded device gf @xmath115 in terms of the retarded gf @xmath116^{-1 } \label{eq : leadgf}\ ] ] of the isolated reservoir : replacing @xmath117 , the retarded device gf results in @xmath118^{-1}\end{aligned}\ ] ] which defines the retarded boundary self - energy @xmath119 with the assumption of vanishing scattering between contacts and device , the keldysh relation for the correlation functions of device and reservoirs , in analogy to provides the in- and outscattering contact self - energy terms @xmath120 where @xmath121 is the lesser / greater gf of the uncoupled reservoir .
a frequently used assumption is that of contacts which are equilibrated due to scattering , which is usually a good approximation for solar cell devices operating at elevated temperature and possessing extended contacts . in this case , the lead correlation functions can be expressed in terms of the retarded and advanced functions using the fluctuation - dissipation theorem , @xmath122\mathbf{a},\end{aligned}\ ] ] where @xmath123 is the chemical potential and @xmath124 $ ] the spectral function of the reservoir .
the whole problem of the coupling to the reservoirs is now reduced to the calculation of the contact gf @xmath125 , which in principle is of infinite dimension , but only needs to be known in the close vicinity of the device boundary , owing to the reduced dimensionality of the coupling matrix @xmath126 , and can therefore be calculated by surface gf methods using decimation techniques @xcite , conformal maps @xcite or complex band methods @xcite .
similar surface gf approaches can also be used for photons @xcite or phonons @xcite in systems that are open in the optical or vibrational sense , respectively .
the effects of interactions between the different degrees of freedom can be considered perturbatively via respective self - energy terms in the same way as the perturbation due to contacts by replacing the perturbation hamiltonian in and with the corresponding interaction term .
alternatively , the self - energies may be derived using variational - derivative techniques @xcite .
[ [ electron - photon ] ] electron - photon + + + + + + + + + + + + + + + the single particle potential for linear coupling of the electromagnetic field to the electronic system is obtained in coulomb - gauge as @xmath127 with @xmath128 the vector potential operator of the electromagnetic field and @xmath129 the momentum operator . to first order in the vector potential
, the interaction results in the singular self - energy term @xmath130 describing the coupling to classical light , which corresponds to a _
mean - field _ treatment of the interaction .
since this self - energy is proportional to the coherent polarization , it leads to off - diagonal entries if a band basis is used @xcite , which can be eliminated using a band - decoupling scheme @xcite , resulting in an effective interband self - energy that is second - order in the field @xcite , e.g. for a two - band model @xmath131 @xmath132 to second order in the vector potential , the self - energy from the fock term of the self - consistent born approximation is @xmath133g(\underline{1},\underline{2})\nonumber\\ & \times\hat{p}_{\beta}(2 ) \overleftrightarrow{\mathcal{d}}_{\alpha\beta}(\underline{2},\underline{1'})|_{1'=1},\label{eq : fock_se}\end{aligned}\ ] ] where the photon gf is defined in .
close inspection of the two expressions shows that the self - energy component in due to the subtraction of the coherent part is formally identical to . in analogy to the formal treatment of the electronic system , a perturbative or variational approach
can be used to derive the photon self - energy component due to electron - photon interaction , according to the expansion in .
to lowest order , corresponding to the _ random - phase - approximation _ ( rpa ) for the polarization function , the transverse photon self - energy reads @xmath134g(\underbar{1},\underbar{2})\nonumber\\ & \times\hat{p}_{\beta}(2 ) g(\underbar{2},\underbar{1}')|_{1'=1}.\end{aligned}\ ] ] [ [ electron - phonon ] ] electron - phonon + + + + + + + + + + + + + + + the effects of the vibrational modes on the electronic degrees of freedom of the system are described in terms of the coupling of the force field of the electron - ion potential @xmath135 to the quantized field @xmath136 of the ionic displacement @xcite , @xmath137,\label{eq : el_phonint_rs}\end{aligned}\ ] ] with the displacement field given by the normal - mode expansion .
the potential felt by electrons in heterostructure states due to coupling to _ bulk _ phonons can thus be written as @xmath138 where @xmath9 is the electron coordinate , and @xmath139 are related to the fourier coefficients of the electron - ion potential @xmath135 @xcite .
the electron - phonon self - energy can be obtained from the interaction potential within many - body perturbation theory in complete analogy to the electron - photon interaction .
the self - energy corresponding to the fock term of the scba appears in the form @xmath140 with @xmath141 . for inhomogeneous systems , one has to consider also the hartree term @xcite , which reads @xmath142\delta(\underbar{1 } , \underbar{2}),\end{aligned}\ ] ] in the case where the phonon gfs are not computed self - consistently , it is often more convenient to use in the derivation of the self - energy the form for the interaction potential
. finally , the rpa - expression of the phonon self - energy required for the renormalization of the phonon propagator reads @xmath143 [ [ carrier - carrier ] ] carrier - carrier + + + + + + + + + + + + + + + in general , there are two types of electronic interactions to be considered in solar cells : electron - electron and electron - hole interactions . while the former affect primarily the intraband - dynamics and are thus of relevance in the discussion of thermalization and relaxation issues in transport , the latter can have a strong impact on the optical properties via the excitonic enhancement of interband transitions .
since we do not consider the case of excitonic solar cells where exciton diffusion is a key process , like in organic photovoltaics , this absorption enhancement will be the only excitonic effect to be discussed .
the most important effect of electronic interactions in junction - based inorganic solar cells is the built - in potential due to bipolar doping and the modification of the electrostatic potential @xmath144 under illumination .
both cases can be treated macroscopically via the solution of poisson s equation @xmath145=n(\mathbf{r})-n_{d}(\mathbf{r } ) , \label{eq : poisseq}\end{aligned}\ ] ] for a given profile @xmath146 of fully ionized dopands and ( static ) longitudinal dielectric function @xmath147 and with the charge carrier density @xmath148 ( including holes ) from the gfs . in the microscopic picture
, the result of this approach corresponds to the hartree - term , i.e. a mean - field level treatment , of carrier - carrier interaction .
the corresponding effective single - particle interaction potential is @xmath149 where @xmath150 is the two - body interaction potential .
the hartree self - energy for this potential is @xmath151 where @xmath144 is the mean - field potential . on the same level of perturbation theory ,
the corresponding fock term reads @xmath152 electron - electron interactions beyond the mean - field hartree - fock level may be considered by explicit inclusion of dynamical screening via the @xmath153 formalism . for practical purposes ,
often a statically screened potential is assumed together with the above forms of the self - energy . concerning the electron - hole interaction beyond poisson s equation , excitonic effects in semiconductor nanostructures
have been discussed for steady state linear absorption or in the regimes of high pulse excitations . for the latter , sophisticated quantum - kinetic theories
were developed @xcite . for extended systems ,
the computational cost of such approaches limits their applicability to special cases of reduced complexity , such as systems that may be described with a few eigenstates , and they are thus not suited for the investigation of transport properties . for this reason , excitonic effects will be considered here only in terms of the coulomb - enhancement of the optical interband self - energy due to the _ coherent _ polarization of the semiconductor system resulting from the coupling to a coherent ( classical ) light field , as introduced in .
the singular interband coulomb term is ( @xmath154 ) @xmath155 where @xmath76 is the ( screened ) coulomb potential , and depends thus on the coherent interband polarization through the interband gf , which the decoupling provides in the form @xmath156\\
\equiv&-\frac{i}{\hbar}\int_{\mathcal{c } } d 2\int_{\mathcal{c } } d3\,\sigma_{vc}^{\delta}(\underline{2},\underline{3})\mathcal{t}_{vc}(\underline{1},\underline{2 } , \underline{3},\underline{1}'),\end{aligned}\ ] ] with the tilde denoting the gf without interband coupling . inserting the explicit expressions for the singular self - energies leads to the bethe - salpeter equation ( bse ) for the coherent polarization , which for steady state reads @xmath157 with @xmath158 the coherent interband polarization of non - interacting electron - hole pairs .
the corresponding self - consistent bse - type equation for the singular self - energy is obtained by using and in eq .
, @xmath159 where @xmath160 . due to the very general grounds of their determination via quantum kinetic equations ,
the negf contain information not only about the electronic , optical and vibrational states of the system , but also about the occupation of these states and the rates of transitions between them .
knowledge of the gfs for carriers , photons and phonons thus immediately provides information about the device characteristics as they are related directly to physical observables : the ensemble average of any single - body operator @xmath161 can be written as @xcite @xmath162\nonumber\\ & = \mp \lim_{\mathbf{r}\rightarrow\mathbf{r}}\lim_{t'\rightarrow t+}\mathrm{tr}[o(\mathbf{r},t ) \mathcal{f}^{<}({\mathbf r},t;{\mathbf r'},t ' ) ] , \label{eq : relgfopaverage}\end{aligned}\ ] ] where @xmath163 and the upper ( lower ) sign applies to fermions ( bosons ) . in photovoltaics ,
the properties of interest determined experimentally cover on the one hand a range of _ spectral _ quantities , such as absorption , emission and transmission spectra , or spectral response and quantum efficiency .
these quantities can be obtained from the gf in the energy ( frequency ) domain . on the other hand ,
there are the _ integral _ quantities which follow from the corresponding spectral versions upon energy integration , such as the charge carrier current density providing the photovoltaic current - voltage @xmath164 characteristics which determine the energy - conversion efficiency of the solar cell device . following the above procedure
, the electron density in steady - state is computed by inserting the electron density operator @xmath165 in eq . and performing the fourier - transform to the energy domain , @xmath166 the hole density is obtained by replacing in the above expression @xmath167 with @xmath168 . in the same way , the photon correlation function yields the photon density via @xmath169 where the integrand is given by planck s law if the correlation function for equilibrium free - field photons is used .
the electronic current density is determined as the ensemble average of the operator @xmath170\\ & \equiv\lim_{\mathbf{r'}\rightarrow\mathbf{r}}\frac{-ie\hbar}{2m_{0}}\left[\nabla_{\mathbf{r } } -\nabla_{\mathbf{r'}}\right]\hat{\psi}^{\dagger}(\mathbf{r})\hat{\psi}(\mathbf{r } ' ) , \label{eq : negfcurr}\end{aligned}\ ] ] and in steady state can be expressed in terms of the carrier gf via @xmath171\int \frac{de}{2\pi}g^{<}(\mathbf{r},\mathbf{r'};e).\ ] ] this form of the current may also be obtained directly from the formulation of the electron continuity equation in terms of the electronic gfs by inspection of the divergence term .
the photon current @xmath172 in the device follows from the evolution of the light intensity , which is given by the symmetrized non - equilibrium ensemble average of the poynting vector operator @xcite , @xmath173 where @xmath174 with @xmath175 the electric and magnetic components of the em field .
recalling the definition of the photon gf , the spectral photon current results in terms of the latter to @xmath176.\end{aligned}\ ] ] the macroscopic balance equation for a photovoltaic system is the steady state continuity equation for the charge carrier density @xmath177 where @xmath178 is the particle current density , @xmath179 the ( volume ) generation rate and @xmath180 the recombination rate of carriers species @xmath181 . in the microscopic theory ,
the divergence of the ( particle ) current density is given by @xcite @xmath182.\label{eq : currcons}\end{aligned}\ ] ] the rhs of the above equation provides a general expression for the microscopic intra- and interband rates of ( potentially non - local ) scattering processes .
current conservation requires the rhs to vanish for energy integration over all bands or states , which means that any scattering contributions originating in transitions in energy space must cancel upon energy integration .
if the integration is restricted to either conduction or valence bands , the above equation corresponds to the microscopic version of and provides on the rhs the total local interband scattering rate .
the total interband current is found by integrating the carrier specific divergence over the active volume , and is equivalent to the total global transition rate and , via the gauss theorem , to the difference of the interband currents at the boundaries of the interacting region . making use of the cyclic property of the trace
, it can be expressed in the form @xmath183\label{eq : totrate}\end{aligned}\ ] ] with units @xmath184=s^{-1}$ ] .
the above equation can be used to define the spectral scattering current @xmath185 via @xmath186 for a given scattering process described by a self - energy @xmath187 , such that @xcite @xmath188,\\ \equiv&\frac{1}{2\pi\hbar}\mathrm{tr}\big[\sigma^{<}_{\phi}(e)g^{>}(e)-\sigma^{>}_{\phi}(e)g^{<}(e ) \big],\end{aligned}\ ] ] which describes the total scattering rate at a given energy as difference of the inscattering rate into an empty state at a that energy @xmath189 $ ] and the outscattering rate @xmath189 $ ] from an occupied state at the same energy .
if we are interested in the interband scattering rate , we can neglect in eq .
the contributions to the self - energy from intraband scattering current , e.g. via interaction with phonons , low energy photons ( free carrier absorption ) or ionized impurities , since they cancel upon energy integration over the band . however , the current flow in a given band is not unaffected by the intraband scattering , since the carrier gfs are modified by the action of the corresponding self - energies in the associated dyson equations . due to its generality ,
the above representation of the global current components in relation to the carrier self - energies has manifold applications , depending on the nature of the self - energies .
first of all , it can be used to express the terminal current at contact @xmath90 in terms of the contact self - energies , @xmath190\end{aligned}\ ] ] for an equilibrium contact characterized by a chemical potential @xmath191 and broadening function @xmath192 , the above current formula results in the meir - wingreen expression @xcite @xmath193.\end{aligned}\ ] ] another important application with relevance in the simulation of solar cells , especially for the so - called hot carrier devices , is the description of energy loss in electronic transport via inelastic scattering processes such as coupling to phonons @xcite , where the dissipated power is described in terms of the inelastic scattering current via @xcite @xmath194 but most importantly , the formalism provides the optoelectronic conservation laws in terms of the optical rates and associated currents via insertion of the electron - photon coupling self - energies in . on the other hand
, the global radiative interband scattering rate equals the total optical rate @xmath195 , which , via the quantum statistical average of the poynting vector operator or directly from the explicit electron - photon self - energy terms in , can be expressed in terms of photon gfs and self - energies @xcite , @xmath196\label{eq : photrate_opt}\end{aligned}\ ] ] and which is related to the global electromagnetic power dissipation through @xmath197 the two terms in eq .
provide microscopic expressions for absorbed and emitted photon flux , which may be regrouped to write the optical rate in terms of the _ net _ absorption , i.e. the absorption minus the stimulated emission , and the _ spontaneous _ emission , @xmath198,\\ r_{\gamma , em}^{opt}(\hbar\omega)=&\frac{1}{v}\mathrm{tr}\big[\overleftrightarrow{\pi}^{\gamma , < } ( \hbar\omega)\hat{\overleftrightarrow{\mathcal{d } } } { } ^{\gamma}(\hbar\omega)\big],\end{aligned}\ ] ] where the trace is over spatial coordinates and the cartesian components of the vector potential , and we have introduced the spectral functions @xmath199 for electron - hole pairs and for photons , respectively .
the above expressions for @xmath200 may be interpreted as global generation and recombination rates @xcite .
the emission term provides a more general formulation of generalized kirchhoff law @xcite normally used in photovoltaics for the photon flux emitted from an excited semiconductor .
it allows for the inclusion of a realistic electronic dispersion via the polarization function @xmath21 , reflecting the effects of electron - electron , electron - hole and electron - phonon interactions and the non - equilibrium occupation of these states , as well as the consideration of the optical modes specific to the geometry of the system . in the electronic picture ,
the separation of the different contributions is not similarly straightforward , since the in- and outscattering self - energies always contain both an absorption and an emission component , e.g. interband absorption and intraband ( free - carrier ) emission in the case of the electron inscattering self - energy .
if the intraband terms are neglected , absorption and emission terms can be identified with the in- and outscattering contributions in , where now the emission comprises both stimulated and spontaneous components . in the electronic expression for the optical rate ,
the gfs correspond to the final state of the scattering process , but the self - energy contains the gfs of the initial state only in the case of direct optical transitions . in the case of indirect , phonon assisted transitions such as those in indirect band gap semiconductors , the scattering process proceeds via an intermediate , virtual state and the associated gfs and self - energies , as shown in fig .
[ fig : selfconsit ] for the example of a simple three - band model of silicon @xcite .
( m)[matrix of math nodes , row sep=5 mm , column sep=3 mm , text height=2.5 mm , text depth=1 mm ] g__v ^e__v vb ( @xmath201 ) states + ^e__c g__c ^ep ,-
x__c virtual cb ( @xmath202 ) states + ^ep ,-
x_x_c g_x_ccb ( @xmath203 ) states + ; ( m-1 - 2 ) edge [ auto ] ( m-1 - 1 ) ( m-1 - 1 ) edge [ bend right ] ( m-2 - 1 ) ( m-2 - 2 ) edge [ bend right ] ( m-1 - 2 ) ( m-2 - 1 ) edge [ auto ] ( m-2 - 2 ) ( m-2 - 3 ) edge [ auto ] ( m-2 - 2 ) ( m-2 - 2 ) edge [ bend right ] ( m-3 - 2 ) ( m-3 - 2 ) edge [ auto ] ( m-3 - 3 ) ( m-3 - 3 ) edge [ bend right ] ( m-2 - 3 ) ; finally , the general formalism to treat scattering within the negf formalism can also be used to find an approach to the description of non - radiative recombination , e.g. via defects , which dominates in most photovoltaic devices . while an exact microscopic treatment is possible only in special cases , a more phenomenological treatment proceeds along the lines of the general formalism introduced above . in order to describe non - radiative recombination via defects ,
the scattering induced renormalization of the gfs of carriers in localized as well as extended ( bulk ) states needs to be quantified by the corresponding self - energy expressions , which are @xmath204 where @xmath205 is the gf of the defect or midgap state , @xmath105 the matrix element of carrier capture or emission by the defect , and @xmath206 for coupling of the defect to conduction and valence band states , respectively , and the upper sign corresponds to the former case . inserting these self - energy terms into the general expression for the electron - capture rate yields @xmath207 expressing the fact that the rate of scattering out of the extended conduction band states by carrier capture into defects equals the rate of scattering into the defect state . using quasi - equilibrium approximation for the carrier gfs , the defect recombination rate derived by shockley , read and hall @xcite is recovered .
for the numerical evaluation of the dynamical equations , gfs and self - energies need to be represented in a basis of finite dimension via a suitable expansion of the corresponding field operators , which converts the former in a linear system to be solved self - consistently with the diverse self - energy equations and the poisson equation for the electrostatic potential .
since the specific implementation depends strongly on the device configuration under consideration , some rather general issues arising in the numerical treatment of the negf formalism for solar cells will be discussed here , as well as the implications of commonly used approximations .
there are several aspects that may have an impact on the specific choice of basis for the carrier field operators .
first of all , there is the electronic structure of the material system : while direct gap semiconductors like the iii - v materials commonly used in optoelectronic applications are reasonably well described by @xmath208 approaches , the situation is more demanding in indirect semiconductor such as silicon - based materials often used in photovoltaics , wherefore atomistic approaches such as empirical or ab - initio tight - binding are preferred . for molecular devices like organic solar cells , ab - initio ,
quantum chemical methods such as density - functional theory are required for the electronic - structure calculation .
there is an important difference between light - emitting optoelectronic devices and solar cells to consider at this point : while both transport and emission take place in a narrow energetic range around the band edge , absorption of solar radiation is a broadband process .
hence , in principle , a full - zone description of the electronic structure is required to cover the photogeneration induced by the entire solar spectrum . apart from the range of energy states described , the largest impact of the choice of basis concerns the spatial resolution and flexibility therein . while effective continuum approaches such as ema or @xmath208 lend themselves to optimized adaptive spatial grids , allowing for coarse - grained treatment of spatially homogeneous regions such as bulk leads and high resolution close to heterointerface , the grid is fixed by the atomic lattice in the case of an atomistic basis , which precludes the description of extended systems , unless one resorts to multiscale approaches @xcite . in some cases , a mode space basis may be preferred over a real space basis , i.e. in the case where only a few modes contribute to the device characteristics .
this is for instance the case for the transverse modes in nanowire transport @xcite , or in periodic superstructures @xcite .
however , in most cases , the mode spectrum in leads or contacts deviates strongly from the discrete mode spectrum of the low dimensional absorber , or , like e.g. in quantum well solar cells , there is a continuous transition from a discrete to a continuous mode spectrum in the energy range of interest .
indeed , the ability to treat on equal footing bound state to bound state and bound state to continuum transitions represents a considerable advantage of real space approaches @xcite . among the numerical issues arising and approximations imposed due to computational limitations ,
the most prominent ones for the photovoltaic applications in mind are inadequate energy mesh discretization and the non - locality of the interactions .
the former problem arises whenever resonances appear in the transmission function of a structure , either due to localization effects leading to the formation of quasibound states or due to van hove singularities in the density of states .
the mesh should be refined around the resonances in order to avoid large errors in the energy integration and resulting convergence problems .
different approaches have been developed to tackle the refinement issue , mainly adaptive algorithms @xcite or methods for the resolution of the poles of the gfs giving rise to the resonances @xcite . in the case where a large number of poles are present
, adaptive refinement according to the resolution of the spectral output quantities is preferrable .
however , in the presence of inelastic interactions such as coupling to broadband illumination , the situation may arise that _ any _ two energies are coupled , extending the need for mesh refinement to the whole energy range and thus making the use of a coarse - grained starting mesh questionable . in any case of an irregular grid
, care has to be taken to use interpolation schemes that guarantee current conservation .
the determination of the full gf provides information on propagation and correlations between any two sites of the dievice and thus includes all non - local phenomena .
however , such a computation is very time and memory consuming , wherefore approximate schemes with a limited number of non - zero off - diagonal gf elements are used , which then allows for the application of fast computational routines such as the recursive gf algorithm @xcite but at the same time reducing the range of non - locality taken into account by the simulation . while the consequences are sizable even for rather localized intraband scattering mechanisms such as coupling to phonons @xcite , they are severe in the case of the interband scattering due to coupling to photons , since in the latter case , due to the comparably long wave length of the light , the non - locality is not restricted by the matrix element of the coupling itself , but by the density of states which couple @xcite .
thus , non - locality is only limited in the case of optical transitions between localized states , as in weakly coupled quantum dot or quantum well absorbers .
-@xmath209-@xmath148 diode configuration used in the simulation[fig : sqw_diode_structure].,height=226 ] in the following , the kind of information provided by the negf formalism shall be illustrated by application to the simulation of two different generic quantum photovoltaic devices , namely a standard iii - v material based single quantum - well photodiode @xcite and a silicon based superlattice absorber @xcite .
while the former device embodies all relevant structural and mechanistic features of the multi - quantum well solar cell , the latter corresponds to a prototypical ingredient of third - generation multi - junction devices .
the two devices are fundamentally different in several aspects of their working principles .
first of all , in the qwsc , the confined states act only as absorbers , while transport takes place in the extended quasi - continuum states of the host material . in the superlattice device ,
both absorption and transport proceed via the states of the coupled quantum wells .
a second important difference is the role of scattering with phonons : while this interaction is a crucial aspect of the carrier escape mechanism in the qwsc , it greatly enhances transport in the superlattice at finite internal field due to restoration of resonant interwell charge transfer .
it is thus instructive to have a closer look at the microscopic picture of charge carrier photogeneration and transport in these two different devices , provided by the negf formalism in the form of spectral currents and rates . in both examples , coupling to equilibrium bulk phonons and isotropic free field photons
is assumed .
@xcite.[fig : bandscheme],height=226 ] the escape of charge carriers from quantum wells under illumination and at finite terminal bias voltage is an excellent example of a quantum photovoltaic process that can only be described properly by a quantum - kinetic approach , since neither the exact non - equilibrium carrier distribution in the qw nor the phonon - assisted tunneling rate can be determined consistently in a semiclassical or ballistic non - local approximation .
the model system used for the investigation of the carrier escape process , consisting of a @xmath210-@xmath209-@xmath148 diode of high band gap material with a single quantum well formed by a slab of low band gap material allocated at the center of the intrinsic region , is shown in fig .
[ fig : sqw_diode_structure ] .
the quantum well thickness is 18 monolayers ( ml ) , with the ml width given by half the lattice constant of the semiconductor material . the dopant concentration in the doped layers of 30 ml extension amounts to @xmath211 @xmath212 .
the electronic structure is described by a simple two - band tight - binding model @xcite providing band gaps @xmath213 ev and @xmath214 ev and band offsets @xmath215 ev , @xmath216 ev . the parameters for electron - photon and electron - phonon interactions correspond to the gaas - al@xmath217ga@xmath218as material system ( see ref .
@xcite for details ) .
doping and band offsets result in a band diagram in growth direction as shown schematically in fig .
[ fig : bandscheme ] . at the operating point of the solar cell ,
i.e. the device state where the product of current and voltage is maximum , the chemical potentials @xmath0 governing the injection of electrons and holes at the respective contacts are split by the corresponding bias voltage , but the occupation of the quantum well states is determined by the complex balance of the rates for photogeneration , radiative recombination , carrier capture and carrier escape .
[ fig : spectral_sqw ] displays these rates together with the resulting excess carrier concentration and current spectrum at a contact fermi - level splitting of 1.3 v and under illumination with monochromatic light at 1.55 ev and high intensity of 17.7 kw / m@xmath219 .
the scattering rates are for electrons , a positive value thus corresponds to inscattering of electrons in the conduction band and to outscattering of holes in the valence band . due to the monochromatic illumination , the generation spectrum is narrow , but the interaction with phonons leads to a clear spectral separation of absorption and emission lines on the one hand ( a ) , and to the formation of phonon satellites in the spectral density of excess carriers on the other hand ( b ) .
current flow is not centered on the energy of generation , but on much higher energy , as the wide triangular barriers prevent a direct tunneling escape from deep qw states ( d ) .
the energy resolved phonon scattering rate ( c ) clearly evidences the phonon mediated scattering of carriers out of the low energy states where they are generated and into the less localized higher energy states with enhanced tunneling escape rate .
the negf formalism is thus able to provide a complete microscopic picture of the thermionic emission process at arbitrary operating conditions .
( a)(b ) owing to the large potential barriers for photoexcited charge carriers ( @xmath383 ev for both electrons and holes ) , transport in si - sio@xmath220 superlattice devices is restricted to quantum - confined superlattice states . due to the finite number of wells and large built - in fields ,
the electronic spectrum can deviate considerably from the minibands of a regular superlattice . by including the coupling of electrons to both photons and phonons ,
the negf theory is able to provide a microscopic picture of indirect generation , carrier relaxation , and inter - well transport mechanisms beyond the ballistic regime .
the model system used to investigate generation and transport in indirect gap superlattice absorbers is shown schematically in fig.[fig : struct](a ) .
it consists of a set of four coupled quantum wells of 6 ml width with layers separated by oxide barriers of 3-ml thickness , embedded in the intrinsic region of a si @xmath210-@xmath209-@xmath148 diode .
the thickness of both doped and spacer layers is 50 ml .
the monolayer thickness is half the si lattice constant . for such thin oxide layers , the confinement and
thus the effective barrier height is reduced , and was chosen at 0.95 ev for both electron and holes , which is still large enough to prevent thermionic emission .
the carriers are described using a multiband effective mass model , accounting for the different conduction band valleys as well as light and heavy holes ( details in @xcite ) .
the doping density is @xmath221 @xmath212 for both electrons and holes .
this composition and doping leads to the band diagram shown in fig.[fig : struct](b ) . in order to investigate the relaxation of photogenerated carriers ,
the superlattice region is illuminated with a photon energy of 1.65 ev , thus exceeding the effective band gap , which at the chosen barrier thickness lies around 1.3 ev . at this photon energy , both first and second electronic minibands
are populated , as can be seen in fig .
[ fig : photrate_sl ] displaying the spatially and energetically resolved photogeneration rate at an intensity of 10 kw / m@xmath219 and at vanishing bias voltage . remarkably , as shown in fig .
[ fig : pc_sl ] , also the electronic current flows in both minibands , relaxation due to scattering is thus not fast enough to confine transport to the band edge .
it is however obvious that transport of photocarriers across the superlattice is not ballistic , but strongly affected by the inelastic interactions and best described by the sequential tunneling picture .
ev and intensity @xmath222 kw / m@xmath223 @xcite[fig : photrate_sl],width=264 ] ev and intensity @xmath222 kw / m@xmath223 @xcite.[fig : pc_sl],width=268 ] it remains to consider the indirect photogeneration process .
to this end , the phonon - mediated intervalley in- and outscattering rates are displayed in fig .
[ fig : phonrate_sl ] for both final electron state in the si valleys close to the x - point and the virtual intermediate state at the @xmath224-point . while in - and out - scattering are balanced in the dark ( a )
, there is a strong net charge transfer from @xmath224 to @xmath225 under illumination , and the inscattering rate reflects the spectral pattern of the photogeneration .
ev and intensity @xmath222 kw / m@xmath223.[fig : phonrate_sl],title="fig:",width=302 ] ev and intensity @xmath222 kw / m@xmath223.[fig : phonrate_sl],title="fig:",width=302 ]
the high efficiency concepts of the next generation of photovoltaic devices pose new requirements on models for the theoretical description of their optoelectronic characteristics .
a theoretical framework suitable for this purpose is available in the negf formalism , if the quantum optics formulation is unified with the picture of dissipative quantum transport .
the resulting theory is then able to provide insight into the modification of the central physical processes of photogeneration , charge separation and carrier extraction due to the use of semiconductor nanostructures as absorber and conductor media . the general consideration all of the degrees of freedom on equal footing furthermore presents a suitable starting point for consistent approximations in cases where some of the subsystems allow for a simplified treatment , as e.g. for bulk modes , equilibrium distributions or negligible coupling parameters .
while the general framework is set , many challenges remain for the application to realistic photovoltaic devices , both in advanced but fundamental aspects such as excitonic contributions to the optical transitions and non - radiative recombination , as well as in the computational efficiency in treating extended system without excessive loss of accuracy . | this article reviews the application of the non - equilibrium green s function formalism to the simulation of novel photovoltaic devices utilizing quantum confinement effects in low dimensional absorber structures .
it covers well - known aspects of the fundamental negf theory for a system of interacting electrons , photons and phonons with relevance for the simulation of optoelectronic devices and introduces at the same time new approaches to the theoretical description of the elementary processes of photovoltaic device operation , such as photogeneration via coherent excitonic absorption , phonon - mediated indirect optical transitions or non - radiative recombination via defect states .
while the description of the theoretical framework is kept as general as possible , two specific prototypical quantum photovoltaic devices , a single quantum well photodiode and a silicon - oxide based superlattice absorber , are used to illustrated the kind of unique insight that numerical simulations based on the theory are able to provide . |
The $10 bill featuring Viola Desmond will make its debut in 2018, when she becomes the first Canadian woman to be celebrated on the face of her country's currency.
"Viola Desmond's own story reminds all of us that big change can start with moment of dignity and bravery," Finance Minister Bill Morneau said as he unveiled the choice during a news conference in Gatineau, Que., on Thursday.
"She represents courage, strength and determination–qualities we should all aspire to every day."
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Self-made makeup maven
Viola Desmond was a cosmetics pioneer for black women in Atlantic Canada. Following in the footsteps of her father, a Halifax barber, Ms. Desmond started out in business at a time when few beauty schools would accept black students. After training in Montreal, Atlantic City and New York, she founded her own institution, Halifax's Desmond School of Beauty Culture, selling her own line of hair and skin products across Nova Scotia. But on one business trip on Nov. 8, 1946, when her car broke down in New Glasgow, Ms. Desmond would become famous for another reason.
A night at the movies
The fateful movie she went to see was The Dark Mirror, a psychological thriller starring Olivia de Havilland. She was at the Roseland Theatre to kill time while a garage repaired her car, which wouldn't be ready until the next day. But the Roseland was a segregated theatre; the floor seats were for whites only, while black patrons were confined to the balcony. Ms. Desmond was shortsighted and needed a better view, and tried to buy a floor seat, but was refused because she was black. She then bought a balcony seat (which was one cent cheaper) but sat in the floor area – until theatre staff called the police and had her dragged out. She spent 12 hours in jail.
"She said, 'I stretched out and I was just getting comfortable and I thought, oh, this is nice, and I won't worry about anything,'" her 89-year-old sister, Wanda Robson, recalled. "And then this usher came up and told her she couldn't sit there."
A nightclub that was once home to the Roseland Theatre is shown in downtown New Glasgow, N.S., on April 29, 2010. PAUL DARROW FOR THE GLOBE AND MAIL
On trial for a single penny
She was charged and convicted of tax evasion – over a single penny. She did not have a lawyer at trial – she was never informed she was entitled to one. Arguing that Ms. Desmond had evaded the one-cent difference between the balcony and floor ticket prices, a judge fined her $26. Protests from Nova Scotia's black community and an appeal to the provincial Supreme Court proved fruitless, and Ms. Desmond died in 1965 without any acknowledgment of racial discrimination in her case.
Colour Code: Discussing Viola Desmond In Episode 4 of The Globe’s podcast on race in Canada, Hannah Sung and Denise Balkissoon explore Viola Desmond's story and discuss the “Angel Complex” Canadians use to compare themselves with the United States on issues of race.
'She is now free'
In 2010, Nova Scotia gave her a free pardon – and the black lieutenant-governor signed it into law. "Here I am, 64 years later – a black woman giving freedom to another black woman," Mayann Francis recalled in a 2014 profile about the pardon, which called Ms. Desmond's case a miscarriage of justice and said she should never have been charged. "I believe she has to know that she is now free."
Nova Scotia lieutenant-governor Mayann Francis signs the official pardon for Viola Desmond as her sister Wanda Robson, left, premier Darrell Dexter and Percy Paris, minister of African Nova Scotian Affairs, look on at a ceremony at the legislature in Halifax on April 15, 2010. ANDREW VAUGHAN/THE CANADIAN PRESS
Rosa Parks comparison
Ms. Desmond has often been compared to Rosa Parks, the U.S. civil rights heroine who refused to give up her seat on the bus to a white passenger in Montgomery, Ala., in 1955.
But Ms. Robson said her sister didn't want to join any formal protest movements. She had her beauty school to run – and that was her inspiration to help her community. "She said, 'I'm not the person to go around and be an activist for something. I will speak anywhere, but I can't make it my life's mission,'" Ms. Robson said. "'My life's mission is to be a hairdresser, to be the beauty consultant for all the black women, any black woman that comes to me, and to teach them, teach them to do what I do, so I can send them out in Nova Scotia or wherever they want to go and work with the black population,'" Ms. Robson said.
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When asked what Ms. Desmond would say if she knew she had been chosen, Ms. Robson answered: "'Don't you wish Mom and Dad were here?'"
Her minute of fame
Ms. Desmond was the first historical woman of colour to get her own Heritage Minute, which was played at the Thursday event where the banknote was announced. Actress Kandyse McClure portrayed her in the Heritage Minute, which had been released this past February for Black History Month. "I am honoured to give voice to a woman whose only crime was the expectation of being treated not as black or as a woman, but as a human being," Ms. McClure wrote in an article for the Huffington Post at the time. Historica Canada has since produced another Heritage Minute focusing on a woman of colour, Inuit artist Kenojuak Ashevak.
The runners-up
Thursday's short list included poet E. Pauline Johnson; Elsie MacGill, who received an electrical engineering degree from the University of Toronto in 1927; Quebec suffragette Idola Saint-Jean; and 1928 Olympic medallist Fanny (Bobbie) Rosenfeld, a track and field athlete.
Famous Five activist Nellie McClung, the Alberta suffragette who fought in the 1920s for women to be legally recognized as persons in Canada, was for many Canadians the most obvious omission from the short list.
There were more than 26,000 submissions from the public, which was later whittled down to 461 eligible nominees who had Canadian citizenship and had been dead for at least 25 years.
The other four finalists for the banknote were, clockwise from top left: E. Pauline Johnson/Tekahionwake (1861-1913), Mohawk poet; Elsie MacGill (1905-1980); Bobbie Rosenfeld (1904-1969), Olympic athlete; and Idola Saint-Jean (1880-1945), Quebec suffragette. PHOTOS: BRANTFORD HISTORICAL SOCIETY, LIBRARY AND ARCHIVES CANADA, THE GLOBE AND MAIL, MONTREAL ARCHIVES
Meet the former Globe columnist who almost made it on your money Bobbie Rosenfeld, an Olympic gold and silver medallist who turned to sports journalism in the 1930s, was one of the Bank of Canada’s five finalists. Here's more background on her and a sample of her work from the Globe archives.
Other banknotes
The new banknote will cause some other changes to Canada's currency.
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Sir John A. Macdonald, Canada's first prime minister, will move from the $10 to a higher denomination, as will Sir Wilfrid Laurier, who is currently on the $5. Another Canadian will be chosen for the $5 note in a similar manner to Ms. Desmond.
Former prime ministers Sir Robert Borden and William Lyon Mackenzie King will be dropped from the $100 and the $50. The $20 bill, which has long featured the Queen, will remain unchanged.
William Lyon Mackenzie King (top) and Sir Robert Borden are being replaced on the $50 and $100 bills. Bank of Canada
With reports from Laura Stone and The Canadian Press
MORE FROM THE GLOBE AND MAIL
Canada’s Rosa Parks gets her due In February, Viola Desmond’s story became the first ever Heritage Minute to have a historical woman of colour as its central focus. Evan Annett crunched the numbers on how the Heritage Minutes treat race and gender. ||||| It was the first story Anisa Hassan saw when she checked the news Thursday morning. Civil rights pioneer Viola Desmond, a black woman, will be immortalized on Canada’s $10 bill.
Viola Desmond will appear on the new $10 bill. ( Courtesy of Wanda and Joe Robson )
Called the “Rosa Parks of Canada,” Desmond defied the colour barrier at a New Glasgow, N.S., movie house in 1946. When the new banknotes enter circulation in 2018, Desmond will be the first woman who is not a Royal to have her face featured on Canadian currency. For Hassan, a young black woman in Toronto, the announcement holds particular significance.
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“For as long as I can remember, I’ve always wondered what it would be like to see people that look like me represented in different parts of our everyday lives,” said Hassan, 25. “For it to be on our money, it’s a big deal.” In 2014, while studying criminology at Ryerson University, Hassan won one of the school’s Viola Desmond Awards, honouring the achievements of black female faculty, staff and students. Hassan was rooting for Desmond as the Government of Canada prepared to put a woman on the new banknotes. Desmond was a beautician, owner of Vi’s Studio of Beauty Culture in Halifax and a beauty school for black women.
On Nov. 8, 1946, trying to see a movie in New Glasgow’s Roseland Theatre, she was told that, because she was black, she would only be allowed to sit in the balcony. Refusing to bow to segregation, the 32-year-old Desmond took a seat on the main floor of the theatre, normally reserved for whites and refused to move.
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Desmond was arrested and spent the night in jail, then charged the following day with attempting to defraud the provincial government, for failing to pay the one-penny tax on ground-floor seats. A judge fined her $20 and ordered her to pay an additional $6 in court costs. In the months after the incident, Desmond fought to have her charge reversed. Her case was taken as high as the Nova Scotia Supreme Court, and, ultimately, her appeal was dismissed in 1947. She died in 1965 at age 50. In 2010, Desmond was granted a posthumous pardon by then-Lt.-Gov. Mayann Francis, and a public apology from then-premier Darrell Dexter. On Thursday morning, Finance Minister Bill Morneau, Status of Women Minister Patty Hajdu and Bank of Canada governor Stephen Poloz announced that Desmond had beaten out four other finalists to be the new face of the $10 bill. “It’s a big day to have a woman on a banknote,” said Desmond’s sister, Wanda Robson, who spoke at the ceremony. “It’s really big day to have my big sister on a banknote.” “She would be so very proud,” Robson added. Yusra Khogali, co-founder of Black Lives Matter Toronto, said she had “a lot of mixed feelings” upon hearing Desmond would appear on the $10 bill. “I thought, symbolically, it was really powerful, but there’s also the reality that (it doesn’t) mean anything, unless politics is also affected,” Khogali said. “There’s continuous attacks on black women on every level of society (from) education to politics to media representations to even the way police engage with us . . . and we know that this is not doing anything to address that.” Still, she said, the new banknote will be a reminder of the segregation lurking in Canada’s history, and of a powerful woman who stood against it. “I think this can be a really big step for us, to advocate and push forward the narratives of blackness and slavery within Canada and how it looks today,” said Khogali. Desmond was one of five accomplished, barrier-breaking women shortlisted for the banknote honour. The runners up were Mohawk artist and poet E. Pauline Johnson; Olympic gold medalist Bobbie Rosenfeld; journalist, feminist and suffragette Idola Saint-Jean, and Canada’s first practicing female engineer, Elsie MacGill, who also became the world’s first female aircraft designer. For Darrell Bowden, a staffer in Ryerson’s Office of Equity, Diversity and Inclusion, and the organizer of the Viola Desmond awards, the recognition is long overdue. “There’s a lot about Viola Desmond that I think we need to be celebrating,” said Bowden. “For what she has done for Canada generally, for black people, and for black women, a population that we know has not always been given the best press.” Bowden grew up in New Glasgow, the town where Desmond was arrested. He lamented that far more Canadians seem to know U.S. civil rights figure Rosa Parks than Desmond. “Viola was not the Rosa Parks of Canada. Rosa Parks was the Viola Desmond of America,” he said. | – Only one woman currently appears on Canadian currency, but Queen Elizabeth II is about to get a partner. Starting in 2018, civil rights pioneer Viola Desmond—aka the "Rosa Parks of Canada"—will have her mug on the country's $10 bill, the Toronto Star reports. The Globe and Mail relays the story that made Desmond famous in November 1946, when her car broke down in New Glasgow, Nova Scotia. While she was waiting for her car to be repaired, she went to see a movie—but because she was nearsighted, she couldn't see well from the balcony seats where black patrons were made to sit. Instead, Desmond took a seat in the whites-only section on the floor. She refused to move when asked and ended up being arrested and spending the night in jail. She was charged and convicted of tax evasion (her balcony ticket cost a penny less than a floor ticket would have) and was fined $26. Desmond took her case all the way up to the Nova Scotia Supreme Court, though her appeal was eventually dismissed. Desmond, who died in 1965 at the age of 50, was officially pardoned in 2010 by the region's black female lieutenant governor. "It's a big day to have a woman on a banknote," Desmond's sister said during the Thursday announcement ceremony about the currency change, per the Star. "It's [a] really big day to have my big sister on a bank note. She would be so very proud." (Some Canadians started slicing their banknotes in half.) |
pre - main sequence stars are commonly surrounded by disks , which serve the dual purpose of funneling accretion onto the central star and transporting away angular momentum .
these disks are also the formation sites of planets and connect protostars and planets physically and chemically .
the main component of gas - rich circumstellar disks , cold h@xmath2 , can not be observed directly because of a lack of transitions at suitable energy levels .
instead , constraints on disk mass , density and temperature structures depend on observations of trace species , most commonly dust and co gas ( e.g. * ? ? ?
* ; * ? ? ?
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to access other disk properties , such as ionization levels , x - ray and uv radiation fields , turbulent mixing , chemical age and bulk composition requires the development of additional molecular probes whose formation and destruction depend critically on one or several of these properties .
the past decade has witnessed significant progress on disk chemistry theory , resulting in large numbers of predictions on how molecular abundance structures should depend on different disk properties ( e.g. * ? ? ?
* ; * ? ? ?
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a lack of observational sensitivity has however limited detections to the simplest molecules in the millimeter / submillimeter range which characterizes the bulk of the gas disk , including co , hco@xmath8 , dco@xmath8 , cn , hcn , dcn , c@xmath2h , h@xmath2co , cs , so , ch@xmath2 , n@xmath2h@xmath8 and hc@xmath1n @xcite .
this list is expected to expand with the arrival of alma and its unprecedented sensitivity and spatial resolution , which will enable the development of a more diverse set of molecular probes . in this _
, we use alma science verification observations of hd 163296 to report the first detection of cyclopropenylidene , @xmath0-c@xmath1h@xmath2 , in a circumstellar disk . at a distance of @xmath9122 pc ( @xcite ) , this herbig ae star ( stellar mass 2.3 m@xmath10 ; spectral type a1 ; age @xmath94 myr ) harbors a large disk ( a scattered light pattern extending out to a radius of @xmath9500 au , @xcite ) with strong millimeter continuum and molecular line emission ( @xcite ) . the large disk size and strong molecular emission
make this system an ideal target to search for new molecules .
the @xmath0-c@xmath1h@xmath2 molecule is a small cyclic hydrocarbon , which was first detected in space by @xcite towards sgr b2 .
since then , @xmath0-c@xmath1h@xmath2 has been detected in a wide range of astrophysical environments , including diffuse and dense clouds , protostars , planetary nebulae and extragalactic sources ( e.g. , * ? ? ?
* ; * ? ? ?
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* ) , and is one of the most abundant molecules with 3 carbon atoms in the interstellar medium @xcite . in the context of disks , @xmath0-c@xmath1h@xmath2 has some favorable characteristics that may make it a powerful molecular probe , especially when observed in combination with isotopologues and chemically related molecules : 1 .
@xmath0-c@xmath1h@xmath2 has two equivalent h nuclei , which couple to generate ortho ( nuclear spin of 1 ) and para ( nuclear spin of 0 ) states .
deviations from the statistical weights of 3 to 1 may be used to constrain the formation conditions of the molecule @xcite .
@xmath0-c@xmath1h@xmath2 is also one of two isomers ; the other is the linear molecule @xmath11-c@xmath1h@xmath2 . the isomer ratio can be used to assess the fractional ionization in clouds @xcite and may provide similar constraints on disks .
3 . the formation and destruction chemistry of @xmath0-c@xmath1h@xmath2 ( and carbon chains ) are sensitive to high energy radiation .
the vertical and radial abundance structure should provide strong constraints on the penetration depth of x - rays and uv photons @xcite .
4 . within the family of hydrocarbons ,
the sensitivity to turbulent mixing increases dramatically from c@xmath2 to c@xmath1h@xmath2 , and from c@xmath1h@xmath2 to larger hydrocarbons . observed ratios and limits have the potential to constrain transport in disks @xcite .
finally , the chemistry that produces @xmath0-c@xmath1h@xmath2 is important to constrain in its own right , since @xmath0-c@xmath1h@xmath2 shares precursors with other , more complex carbon chains , which may be an important source of carbon during planet formation . in light of these possibilities
, we aim to provide first constraints on the abundance , distribution and @xmath12 ratio of @xmath0-c@xmath1h@xmath2 in the hd 163296 disk .
hd 163296 ( ra : 17@xmath1356@xmath1421287 , dec : @xmath152157@xmath162239 ; j2000.0 ) was observed on 2012 june 9 , june 23 and july 7 as part of the alma science verification ( sv ) program in band 6 . at the time of observations , 25 12-m antennae were used
( 2 7-m aca antennae were present in the dataset but flagged ) in the array with a resulting synthesized beam size of 0.9@xmath170.7@xmath18 ( pa=84 ) .
the source was observed with a total integration time of 84 minutes .
the alma correlator was configured to simultaneously observe four spectral windows ( two in each sideband ) .
one of those windows ( spwid # 1 ) covered both @xmath6co and c@xmath19o @xmath20 lines ( 220.399 and 219.560 ghz , respectively ) .
the data were calibrated in the casa software package ( v3.4 ) , following the detailed calibration and imaging scripts provided by the alma science verification team .
since those scripts , along with fully calibrated measurement sets , are publicly available online , we do not repeat the details here .
the 218 ghz ( 1.37 mm ) continuum was generated from the line - free channels in the two spectral windows ( spwid # 0 and # 1 ) of the lower sideband , and the flux is determined to be 608.5@xmath212.5 mjy , which agrees with the sma observations @xcite .
excellent agreement is also seen between the sma and alma spectra for the @xmath6co and c@xmath19o @xmath20 lines with fluxes within 10% @xcite .
all of the @xmath0-c@xmath1h@xmath2 lines are continuum - subtracted and retrieved from spwid # 0 with a channel width of 0.488 mhz ( 0.67 km s@xmath22 ) covering the total 1.875 ghz bandwidth from 216.167 to 218.042 ghz .
we have binned the lines in channels of 1 km s@xmath22 to achieve higher signal - to - noise ratios and still keep the key kinematic features of the disk .
the resulting line rms noise level is estimated to be 2.2 mjy beam@xmath22 per 1 km s@xmath22 channel in line free channels .
figure [ fig : mom ] shows that the @xmath0-c@xmath1h@xmath2 @xmath3 line is clearly detected towards hd 163296 and that the position angle of its resolved velocity field is consistent with that of @xmath6co from the same data set , which shows a clear pattern of keplerian rotation .
interestingly , the @xmath0-c@xmath1h@xmath2 @xmath3 moment map displays a double - peaked morphology , indicative of an inner hole .
the @xmath0-c@xmath1h@xmath2 @xmath23 and @xmath24 lines are only tentatively detected , insufficient to resolve the velocity field or any spatial structure . to improve the sensitivity in imaging these lines
, we applied a gaussian taper to the visibility data that corresponds to 1 fwhm in the image domain , which resulted in a beam of 1.3@xmath171.2@xmath18 ( pa=78 ) . because the line emission changes position with channels , using a single mask for all channels to extract spectra will lead to a degradation of the signal .
instead , we create separate masks to cover the @xmath0-c@xmath1h@xmath2 @xmath3 line emission at each channel and use these masks to extract the line spectra .
the same masks are also used for other @xmath0-c@xmath1h@xmath2 lines .
figure [ fig : spec ] shows the resulting spectra of all three @xmath0-c@xmath1h@xmath2 @xmath23 lines together with @xmath6co @xmath20 line ( with its own masks covering the @xmath6co @xmath20 emission at each channel ) . the @xmath3 line is clearly detected with the expected line shape and v@xmath25 consistent with @xmath6co .
the @xmath24 line presents a consistent spectral profile , at lower signal - to - noise ratio .
in contrast , the @xmath23 line is both narrower and clearly blue - shifted , suggestive of a different physical origin , perhaps in a disk wind .
however , both the @xmath23 and @xmath24 lines are observed at the edge of the spectral window , so this apparent asymmetry should be confirmed by independent observations before any strong conclusions are drawn .
the integrated fluxes are reported in table [ tab : line ] .
these are just below the upper limits reported in two previous failed searches of @xmath0-c@xmath1h@xmath2 in disks @xcite .
we explore the distributions of @xmath0-c@xmath1h@xmath2 in hd 163296 based on a previously developed accretion disk model with well - defined temperature and density structures @xcite . to simulate and compare with the data , we assume the disk material orbits the central star in keplerian motion , and fix the disk geometric and kinematic parameters that affect the observed spatio - kinematic behavior of the disk .
the details of the stellar and accretion properties and the disk geometric and kinematic parameters are summarized in table 3 of @xcite .
we have developed a physically self - consistent accretion disk model with an exponentially tapered edge that matches the spectral energy distribution and spatially resolved millimeter dust continuum emission .
the disk temperature and density structures are further constrained by multiple co and co isotopologue line observations .
such analysis provides the essential framework for constraining the distribution of molecular abundances in protoplanetary disks . within this model framework ,
we assume that @xmath0-c@xmath1h@xmath2 is present with a constant abundance in a layer with boundaries toward the midplane and toward the surface of the disk @xcite . this assumption is motivated by chemical models ( e.g. * ? ? ?
* ) that predict a three - layered structure where most molecules are photodissociated in the surface layer , frozen out in the midplane , and have an abundance that peaks at intermediate disk heights .
the surface ( @xmath26 ) and midplane ( @xmath27 ) boundaries are presented in terms of @xmath28 , where @xmath29 is the hydrogen column density measured from the disk surface in the adopted physical model .
this simple model approach approximates the vertical location where @xmath0-c@xmath1h@xmath2 is most abundant . due to the limited signal - to - noise of the multiple @xmath0-c@xmath1h@xmath2 line detections
, we can not constrain the location of this vertical layer based on the @xmath0-c@xmath1h@xmath2 data .
we therefore fix the vertical surface boundary @xmath26 as 0.32 ( @xmath30 ) and the midplane boundary @xmath27 as 3.2 ( @xmath31 ) , between which lies the expected location of most molecules with peak abundances in the warm molecular layer @xcite .
we model the radial column density distribution of @xmath0-c@xmath1h@xmath2 as a power law n@xmath32 , where n@xmath33 is the column density at 100 au in @xmath7 , @xmath34 is the distance from the star in au , and @xmath35 is the power - law index . since the emission shows a clear indication of a central hole , we fit for both an inner radius r@xmath36 and outer radius r@xmath37 together with the power - law parameters ( n@xmath33 and @xmath35 ) .
using the structure model and the fixed vertical distributions , we compute a grid of synthetic @xmath0-c@xmath1h@xmath2 j=@xmath3 visibility datasets over a range of r@xmath37 , r@xmath36 , @xmath35 and n@xmath33 values and compare with the observations .
the best - fit model is obtained by minimizing @xmath38 , the weighted difference between the real and imaginary part of the complex visibility measured in the ( @xmath39)-plane sampled by the alma observations .
we use the two - dimensional monte carlo model ratran @xcite to calculate the radiative transfer and molecular excitation .
the collisional rates are taken from @xcite and the molecular data file is retrieved from the leiden atomic and molecular database @xcite .
figure [ fig : chi2 ] shows the @xmath38 surfaces for the r@xmath36 and @xmath40 versus the power law index @xmath35 .
we find the @xmath35 is constrained between -2.5 and -1.5 , r@xmath36 1540 au and r@xmath37 150200 au ( within 1@xmath41 ) with best - fit values at -2 , 30 and 165 au , respectively ( reduced @xmath42 ) . by
fixing the above parameters at their best - fit values , n(@xmath0-c@xmath1h@xmath2 ) is determined to be 2.2@xmath210.2 @xmath1710@xmath5 @xmath7 at 100 au .
figure [ fig : chmap ] presents comparisons between the observed channel maps and the best - fit model .
the residual image does nt show any significant emission , which indicates that the @xmath0-c@xmath1h@xmath2 emission is consistent with that arising from a keplerian rotating disk .
the @xmath3 line is actually blended with the @xmath43 ( ortho ) and @xmath44 ( para ) lines at the same frequency . since the einstein @xmath45-coefficients for both ortho and
para lines are the same , 5.393@xmath1710@xmath46 s@xmath22 @xcite , we fit the data with the ortho line only and the resulting column density can be accounted as the sum of both ortho and para forms of the molecule . for the weaker @xmath24 ortho line ,
the signal - to - noise ratio is too low to provide any constraints on the @xmath0-c@xmath1h@xmath2 the distribution . by assuming the @xmath0-c@xmath1h@xmath2 distribution derived from the @xmath3 line , however
, we can use the unresolved line flux to constrain the @xmath12 ratio .
the resulting best - fit n(c@xmath1h@xmath2-(@xmath47))=1.6@xmath210.3 @xmath1710@xmath5 and n(c@xmath1h@xmath2-(@xmath48)=2.2@xmath210.2 @xmath1710@xmath5 @xmath7 at 100 au ( as shown above ) .
hence @xmath12=2.7@xmath211.7 , which is close to the statistical value of 3 , but the large uncertainty implies that better data are required to use this ratio as a probe of formation conditions .
we have clearly detected @xmath0-c@xmath1h@xmath2 in the disk around hd 163296 .
this is one of the two largest molecules detected in disks so far , the other being hc@xmath1n , also a carbon - chain molecule , detected recently using deep single - dish observations @xcite . using the spatially and
spectrally resolved line emission , we have constrained the radial distribution of @xmath0-c@xmath1h@xmath2 in the hd 163296 disk as a ring structure ranging from @xmath930 to @xmath9165 au .
the outer edge of @xmath49250 au ( 2@xmath41 limit ) is much smaller than the gas disk size which extends to 500 au @xcite , which suggests that @xmath0-c@xmath1h@xmath2 formation is slow or that @xmath0-c@xmath1h@xmath2 destruction is fast in the outer disk . in terms of formation
, the best - fit outer radius coincides with the previously determined location of the co midplane snow line , and it is possible that co freeze - out limits the carbon available in the gas phase to form hydrocarbons in general and @xmath0-c@xmath1h@xmath2 in particular .
a second characteristic of the outer disk is that it is rather tenuous because of a rapidly decreasing column density outside of 200 au @xcite .
this may result in efficient penetration of radiation and thus destruction of the easily dissociated @xmath0-c@xmath1h@xmath2 .
explicit model predictions are required to resolve which effect drives the disappearance of @xmath0-c@xmath1h@xmath2 in the outer disk .
no existing disk chemistry model in the literature contains predictions for the radial distribution of @xmath0-c@xmath1h@xmath2 .
based on strong correlations found between @xmath0-c@xmath1h@xmath2 and cch in several astrophysical environments @xcite , predictions on cch in disks can be used to shed further light on the origins of @xmath0-c@xmath1h@xmath2 .
@xcite predicts a cch central cavity in the absence of x - ray radiation ; when x - rays are present , and hd 163296 is a known x - ray emitter @xcite , the cch column is instead centrally peaked . despite the presence of x - rays , the central cavity could be due to a uv dominated radiation field .
this may be tested by observing @xmath0-c@xmath1h@xmath2 towards t tauri stars with weak uv fields and strong x - rays , and towards additional herbig ae stars with weak x - rays .
the inner cavity could also be a product of the main formation pathway of @xmath0-c@xmath1h@xmath2 .
carbon chains can form through at least three different pathways : ( 1 ) ion - neutral reactions at low temperatures , ( 2 ) photo - erosion of larger carbonaceous compounds , and ( 3 ) neutral - neutral reactions at luke - warm temperatures following ch@xmath50 ice evaporation at @xmath930 k @xcite .
detailed modeling of @xmath0-c@xmath1h@xmath2 radial distributions in each of these formation scenarios are clearly needed to use @xmath0-c@xmath1h@xmath2 rings as tracers of the radiation field and other disk characteristics .
in addition to more detailed modeling , additional observations are needed to constrain whether different hydrocarbons , especially cch and @xmath0-c@xmath1h@xmath2 , are correlated in disk environments , and to constrain the vertical distribution of these molecules .
the latter requires multiple lines with a range of excitation energies . with the combined advance in theory and observations
, @xmath0-c@xmath1h@xmath2 may become one of the more useful probes of penetration of the radiation fields in disks .
this paper makes use of the following alma data : ads / jao.alma#2011.0.00010.sv .
alma is a partnership of eso ( representing its member states ) , nsf ( usa ) and nins ( japan ) , together with nrc ( canada ) and nsc and asiaa ( taiwan ) , in cooperation with the republic of chile .
the joint alma observatory is operated by eso , aui / nrao and naoj . + we would like to thank an anonymous referee for thoughtful suggestions for the paper .
we also acknowledge nasa origins of solar systems grant no .
nnx11ak63 . , k. m. , carilli , c. l. , & reid , m. j. 1999 , in astronomical society of the pacific conference series , vol .
156 , highly redshifted radio lines , ed . c. l. carilli ,
s. j. e. radford , k. m. menten , & g. i. langston , 218 | we report the first detection of @xmath0-c@xmath1h@xmath2 in a circumstellar disk . the @xmath0-c@xmath1h@xmath2 j=@xmath3 line ( 217.882 ghz ) is detected and imaged through atacama large millimeter array ( alma ) science verification observations toward the disk around the herbig ae star hd 163296 at 0.8@xmath4 resolution .
the emission is consistent with that arising from a keplerian rotating disk .
two additional @xmath0-c@xmath1h@xmath2 transitions are also tentatively detected , bolstering the identification of this species , but with insufficient signal - to - noise ratio to constrain the spatial distribution . using a previously developed model for the physical structure of this disk
, we fit a radial power - law distribution model to the @xmath0-c@xmath1h@xmath2 @xmath3 emission and find that @xmath0-c@xmath1h@xmath2 is present in a ring structure from an inner radius of about 30 au to an outer radius of about 165 au .
the column density is estimated to be 10@xmath510@xmath6 @xmath7 .
the clear detection and intriguing ring structure suggest that @xmath0-c@xmath1h@xmath2 has the potential to become a useful probe of radiation penetration in disks . |
NASA abruptly called off space shuttle Endeavour's final launch Friday because of a puzzling heater failure in a critical power unit, disappointing huge crowds converging on the area for the afternoon liftoff.
The space shuttle Endeavour sits on Launch Pad 39-A during fueling at Kennedy Space Center in Cape Canaveral, Fla., Friday, April 29, 2011. Endeavour, on her final flight, is scheduled to lift off this... (Associated Press)
The space shuttle Endeavour sits on Launch Pad 39-A during fueling at Kennedy Space Center in Cape Canaveral, Fla., Friday, April 29, 2011. Endeavour is scheduled to lift off one her final flight this... (Associated Press)
In this picture made available by NASA, the last crew of the space shuttle Endeavour stands together on Launch Pad 39A in front of its external fuel tank and solid rocket boosters at the Kennedy Space... (Associated Press)
The space shuttle Endeavour is seen on launch pad 39a as a storm passes by prior to the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral,... (Associated Press)
Space shuttle Endeavour sits on the launch pad at the Kennedy Space Center at Cape Canaveral, Fla., Thursday evening, April 28, 2011. The Endeavour is scheduled for a Friday afternoon launch. (AP Photo/J.... (Associated Press)
President Barack Obama and his family were planning to watch Endeavour blast off. It would have been the first time in NASA history that a sitting president and his family witnessed a launch. Already at Cape Canaveral for the liftoff was wounded Rep. Gabrielle Giffords, wife of the shuttle's commander.
Launch commentator George Diller said the next try likely would be Monday at the earliest. Officials huddled in launch control, discussing a path forward.
"They are trying to assess what all is going to be required and how much time we're going to need," Diller said. "We still don't know what's wrong or why these multiple heater failures occurred."
Commander Mark Kelly and his crew were already on their way to the launch pad, when NASA announced the delay. The astronauts' van did a U-turn at the launch control center, and returned the astronauts to crew quarters.
The first family had not yet arrived in Florida when launch was canceled.
Around noon (1600 GMT), NASA reported that two heaters on an auxiliary power unit had failed. Engineers could not understand the problem and were uncomfortable about proceeding with the 3:47 p.m. (1947 GMT) launch. An electrical short was suspected.
Three power units provide hydraulic pressure to the main engines at liftoff and to the rudder and speed brake during landing. They are crucial components; each must be working perfectly before launch.
The news took guests by surprise as well as journalists who were outside watching the astrovan drive by. There was confusion when the van pulled into the driveway in front of launch control, rather than head straight for the pad three miles (five kilometers) away. Then the official announcement came over the speakers.
Endeavour's mission to the International Space Station is the last in its 19-year history. The shuttle was built to replace Challenger, destroyed during liftoff in 1986, and made its maiden voyage six years later.
Obama will still travel to Cape Canaveral Friday to tour an orbiter processing facility at NASA.
It's unclear whether Obama will meet with fellow Democrat Giffords when he is in Florida.
From Cape Canaveral, Obama will head to south Florida to deliver a commencement address at Miami Dade College.
___
Online:
NASA: http://www.nasa.gov/shuttle ||||| NASA mission managers say they'll try again to launch the space shuttle Endeavour as early as Monday, once they figure out the cause of a puzzling problem with heaters in one of the craft's auxiliary power units.
Friday's high-profile countdown was called off even as Endeavour's six-man crew was heading for Launch Pad 39A. Liftoff would be delayed for at least three days, and possibly longer, NASA launch director Mike Leinbach said.
"We will not fly this machine until it's ready, and today it was not ready to go," he told journalists.
The shuttle's three auxiliary power units provide hydraulic pressure to operate the control system during atmospheric flight. Although the shuttle can operate with only one of the units working, NASA's launch rules state that all three have to be functional for liftoff.
One of the thermostats in the heating system apparently suffered a hard failure, and another was exhibiting "funny behavior," Leinbach reported. He said engineers suspect that there may be a short circuit either in a switchbox or in an electrical line leading to the box.
"If we can go down the easy path, we're still on track for Monday morning," he said. But Leinbach said NASA might have to delay the next launch attempt for more than a week if the problem turns out to be complicated. He expected a weekend round of troubleshooting to tell the tale.
The delay meant that hundreds of thousands of spectators would miss out on seeing Endeavour's final liftoff on Friday. Would-be witnesses included President Barack Obama and his family; and U.S. Rep. Gabrielle Giffords, who was critically wounded during a January mass shooting.
Giffords — who is married to Endeavour's commander, Mark Kelly — was flown to Florida from her Houston rehabilitation center this week to watch the launch. "Bummed about the scrub!!" the congresswoman's staff wrote in a Twitter update. "But important to make sure everything on shuttle is working properly."
"We're all bummed," NASA astronaut Ron Garan tweeted back from the International Space Station, Endeavour's intended destination.
Thousands go home disappointed
Giffords and the Obamas were to watch the liftoff from secure locations here at Kennedy Space Center in Florida, while NASA expected as many as 750,000 other spectators to gather at VIP areas and public viewing spots. Thousands of people had already taken up places along the roads surrounding the launch site and had to go home disappointed.
Despite the launch scrub, Obama and his entourage were flown in to Kennedy Space Center on military helicopters for a quick tour of NASA facilities, allowing the president to meet with Kelly and Giffords as well as other members of Endeavour's crew and their families.
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The launch was called off less than four hours before the scheduled 3:47 p.m. ET liftoff time, just as Kelly and his crew were heading out toward the launch pad. The van carrying the crew stopped at NASA's launch control center, then turned around to return to crew quarters as word of the postponement got out.
Before the postponement, forecasters said there was a 70 percent chance of acceptable weather for launch. When the appointed time for liftoff came, they said Endeavour would have been "go" for launch if weather were the only determining factor. Mike Moses, who chairs NASA's pre-launch mission management team, said that fact served to rub "a little salt in the wound."
Endeavour's mission to the space station, known as STS-134, represents the shuttle's last scheduled flight before retirement and the second-last flight of the 30-year space shuttle program.
15 tons of supplies
Endeavour is loaded up with nearly 15 tons of supplies and equipment, highlighted by the 7.5-ton Alpha Magnetic Spectrometer, which will be attached to the space station's exterior during a robotic arm operation. Once it's installed, the $2 billion particle detector will almost immediately start sending down data about cosmic rays.
Physicists from 16 nations have worked for 17 years to build the AMS, and for a while it looked as if all that effort would be wasted. Fortunately, Congress and NASA worked together to get the van-sized device on this mission. Over the next decade or longer, physicists hope that findings from the AMS will shed light on the mysteries surrounding the nature of dark matter, and the balance of matter and antimatter in the universe.
Endeavour's payload also includes a platform that will be used to store spare parts at the station, communication equipment and a wide range of scientific experiments.
Shuttle program's last spacewalks
Four spacewalks are to be conducted during the shuttle's visit, marking the last outings by shuttle astronauts at the space station. The spacewalkers are to install equipment, do electrical work and conduct maintenance on the station's cooling system and robotic arm system.
In addition to Kelly, the all-male, all-veteran crew includes pilot Greg Johnson, spacewalkers Mike Fincke, Drew Feustel and Greg Chamitoff, and Italian astronaut Roberto Vittori. The mission is currently scheduled to last 14 days, but NASA could extend it another day or two.
When Endeavour's mission is over, it will be prepared as a museum piece for the California Science Center in Los Angeles. NASA has scheduled only one more shuttle flight to the station, to be taken on by Atlantis this summer.
After the shuttles retire, NASA will have to depend on Russian, European and Japanese transports to get supplies to the space station — at least until next year, when U.S. commercial cargo flights are due to begin. NASA hopes that commercial crew transports will become available starting in the middle of this decade.
Earlier this month, NASA said it would pay up to $269.3 million to four companies — Blue Origin, the Boeing Co., Sierra Nevada Corp. and SpaceX — to work on those future spaceships. Mark Sirangelo, Sierra Nevada's executive vice president, said he saw the program as a "bridge" between the shuttle era and the next stage of human spaceflight.
"I don't see it as an end," he told reporters. "I see it as the beginning of the next step."
More from Cape Canaveral: | – No Endeavour launch today—or probably this weekend either. NASA postponed the high-profile launch to investigate trouble with heaters in the shuttle's power system, reports MSNBC. No word yet on what that means for the day's most awaited spectator, Gabby Giffords. Husband Mark Kelly and crew were less than four hours from liftoff when the news broke. The next attempt will likely be Monday at the earliest, reports AP. "They are trying to assess what all is going to be required and how much time we're going to need," said a NASA official. "We still don't know what's wrong or why these multiple heater failures occurred." Despite the postponement, President Obama planned to travel to Cape Canaveral anyway for a tour and a possible meeting with Giffords. |
Dreamcatcher Foundation volunteers drive around Chicago’s West Side and Cicero on Oct. 5, 2017, looking to help prostitutes. (Nancy Stone / Chicago Tribune)
Dreamcatcher Foundation volunteers drive around Chicago’s West Side and Cicero on Oct. 5, 2017, looking to help prostitutes. (Nancy Stone / Chicago Tribune)
More than 10 years have passed, but Margaret Gomez’s family members still look for the man they believe strangled the 22-year-old and left her in a muddy lot in the shadow of the Stevenson Expressway. They don’t expect to find him but feel it’s something they must do. That and pray. “Lately, I said a prayer to the Virgin Mary,” the mother, who shares the same name as her daughter, told a reporter in a quiet voice. “And then you called. Maybe it’s a sign?” Other families have waited even longer for an answer. Over the last 17 years, at least 75 women have been strangled or smothered in Chicago and their bodies dumped in vacant buildings, alleys, garbage cans, snow banks. Arrests have been made in only a third of the cases, according to a first-ever analysis by the Tribune. While there are clusters of unsolved strangulations on the South and West sides, police say they’ve uncovered no evidence of a serial killer at work. If they are right, 51 murderers have gotten away with their crime. Fifty-one people who used belts, bras, ropes, packing tape or their bare hands to kill these women. Fifty-one families still looking for justice for a mother, a sister, a daughter. It has mostly been a silent vigil. There have been few news stories and even fewer memorials or other public gestures that would have focused attention on these women and how they died. The Tribune began reviewing their cases while following up on the largely ignored story of a woman strangled last summer, her body dumped along a curb on the West Side. We wanted to find out how many other women had been strangled and abandoned: Who were they and had their killers been caught? “It’s a staggering number,” said Kaethe Morris Hoffer, executive director of the Chicago Alliance Against Sexual Exploitation. “It is odd how easy it is to disrupt people’s sense of comfort when a large number of people are all killed at once. It is likewise upsetting to realize how, if you spread out over a long period of time, how inured people are to the murdering of women, particularly marginalized women.” Chuck Berman / Chicago Tribune Loree Williams prays in front of a photo of his cousin Theresa Bunn in November 2007 during a vigil near Washington Park on Chicago’s South Side — at the site where her strangled body was found that year. Loree Williams prays in front of a photo of his cousin Theresa Bunn in November 2007 during a vigil near Washington Park on Chicago’s South Side — at the site where her strangled body was found that year. (Chuck Berman / Chicago Tribune) (Chuck Berman / Chicago Tribune) The Tribune searched through thousands of pages of medical examiner records and public crime reports to build a database. Here is what we found: • At least 75 women have been strangled or smothered in the city since 2001, the earliest year that crime reports on the slayings were publicly available. Many of them struggled with drugs or prostitution, making them particularly vulnerable to predators on the street. Some had no arrest records at all. • Twenty-five of the cases have been closed with the arrests of 13 men, some of them charged with more than one murder. That leaves 67 percent still unsolved. The Police Department would not say if there are active suspects in those cases, but officials reviewed more than a dozen of them after they were contacted by the Tribune and have referred three to cold case detectives. • There are clusters of strangulations around Washington Park on the South Side and Garfield Park on the West Side. Twenty-seven slayings happened in three police districts on the West, South and Far South sides long marked by violence and drug use. Of those, just two have been solved. Around Washington Park, two women were strangled and left in burning trash bins over two days in November 2007. Theresa Bunn, 21 years old and eight months pregnant, was found south of the park. Hazel Lewis, 52, was found the next day north of the park behind an elementary school. Neither case has been solved. • The women ranged in age from 18 to 58, and most of them were African-American. One of the victims was a grandmother of 20 and a great-grandmother of two. Others were nurses, waitresses or young women hoping to finally conquer their addictions and go back to school. • At least 47 of the women had histories of prostitution. Based on the Tribune’s analysis, along with interviews with women who worked in prostitution, strangulation is one of the main ways people in the sex trade have been killed in Chicago over the last two decades. “It’s upfront and personal,” said Brenda Myers-Powell, a former prostitute who co-founded The Dreamcatcher Foundation, an organization that provides outreach and mentoring for those in the sex trade. “I have been (choked) so much, it became, like, you don’t let guys get close to your neck.” Autopsy reports indicate some of the women were also raped and beaten. Some were gagged; some had plastic bags tightened around their head. One had a broken nose; others suffered severe head injuries and bruises over their bodies. “The brutal nature of these crimes is very disturbing,” said Chief of Detectives Melissa Staples. Staples, along with victim advocates, say the dangerous world some of these women frequent makes it more difficult to solve their slayings. The last person with the victim is often unknown. People use aliases. Witnesses don’t trust cops. DNA evidence doesn’t always lead to a suspect. In the late 1990s and early 2000s, when the bodies of dozens of women were found, the Police Department responded by forming a task force that solved the slayings of 40 women. The task force was eventually disbanded even as, the Tribune review shows, the attacks continued at a steady pace. Staples is not certain the task force needs to be reinstated. But Cook County’s top prosecutor said it is worth considering to raise the “level of urgency” in clearing cases. “If we knew there was someone picking off children on their way to school, I think the fierce urgency of trying to figure out who would require us to (have a task force),” State’s Attorney Kim Foxx said in a recent interview. “That is not the level of urgency we have with these women.” ‘She wanted friends. And this is what happened’ A dozen years ago, Margaret Gomez left home for the last time, chasing a heroin addiction that crushed the spirit of the slight, doe-eyed young woman. Her mother, also named Margaret Gomez, had moved her daughter to the western suburbs when she was a child in search of streets safer than outside her Little Village home. Gomez said her family was stable. She had high expectations for her daughters, who were close to one another. And she was a strict mother, she said, unafraid to ground her children for months if they broke rules. Her daughter thrived for a time. She was on the cheerleading squad. She loved art and was featured, with a toothy smile, on the front page of the local paper after winning a contest. But Gomez said her daughter was shy, had low self-esteem and, like most adolescents, longed for friends. “She just wanted everyone to like her. She wanted friends. And this is what happened to her.” Family photo Margaret Gomez was strangled and killed over 10 years ago in Chicago, and the case remains unsolved. Margaret Gomez was strangled and killed over 10 years ago in Chicago, and the case remains unsolved. (Family photo) (Family photo) The family believes Margaret got addicted to drugs while hanging out at a park near the family home. She had a boyfriend who used drugs. She was crazy about him. Soon she went missing for days and would return home battered, her glasses often broken.
Through tears, family members recalled their desperate efforts over four years to help her. They found a spot at a rehab facility, but her boyfriend wouldn’t go with her and she refused to go without him. Friends of the family who worked in law enforcement would often track her down on the West Side and bring her home. Her mother would sometimes take harrowing drives in search of her wayward daughter. There were patches of success. Margaret earned her GED and worked as a waitress, a job listed on her death certificate. Along with her sisters, she received First Communion and was confirmed as an adult, two rites of passage in their Catholic faith. As with many of the women found strangled, addiction had a tight grip on Margaret. Here’s how she described herself in a letter left on her mother’s dining room table months before she was killed: “Momma,” she wrote in pencil on lined paper her mother keeps neatly folded inside a plastic baggie. “I wanted to let you know how thankful I am having such a forgiving, caring + determend mother. … I know how much stress + heart ach I put you through and I want to apologize and promise it won’t happen again. I had hit a point where I had become real weak and I don’t know how I let it get that bad. .. I only want improvements from this day on. I LOVE YOU + LOVE how your always on my side no matter what.” Nancy Stone / Chicago Tribune A letter Margaret Gomez wrote to her mother shortly before she was killed. A letter Margaret Gomez wrote to her mother shortly before she was killed. (Nancy Stone / Chicago Tribune) (Nancy Stone / Chicago Tribune) Margaret’s body was found in a gravel lot in the 4200 block of South Knox Avenue on the Southwest Side. She was partially clothed, lying on her back in mud, a brown rope around her neck. On her upper back was a tattoo that read, “Love Mom.” She was 22. The family says police pushed hard to gather evidence in the initial weeks. But in retrospect, family members think investigators focused on the wrong suspect. After about a month, the drive of the detectives seemed to ease, they said. No arrest was made. More than a decade later, altar candles remain lit on dressers and walls. “I just ask Jesus if he would find the killers,” Gomez said of her nightly routine. “And I tell her I love her.” ‘A lot of these women want out’ Catherine Saterfield-Buchanan’s body was discovered under a street light not long after midnight on a June morning last year, the latest woman to be found strangled on Chicago’s streets, according to the Tribune database. Saterfield-Buchanan was lying on her back near a large tree, legs splayed over the curb. Police covered her with a white sheet as a few curious neighbors gathered in the East Garfield Park neighborhood. Her feet poked out the bottom amid empty bottles and shattered glass. Her face was badly beaten. Her slaying also remains unsolved. Saterfield-Buchanan was 58 and, like most of the victims, was older than Margaret. She had finally come for help to Breakthrough on West Carroll Avenue, a sunny, loftlike shelter and health center. Cheron Massonburg, director of adult services at Breakthrough, said many of the women there have experienced traumatic childhoods or poverty and homelessness. They are often estranged from families. Saterfield-Buchanan struggled with learning disabilities and was arrested at least once for prostitution.. “They have experienced some things most of us couldn’t comprehend,” she said. “A lot of women want out, but they just don’t know how.” A report last year by the Cook County sheriff's office surveyed 172 women who worked in prostitution and found 44 percent of them had started working in the sex trade before the age of 18. More striking, 37 percent reported starting before they were 16. One said she began at 9. An alarming number of the women surveyed — 88 percent — said they had experienced violence, such as a beating. And 35 reported being sexually assaulted as an adult. Massonburg said she last saw Saterfield-Buchanan at the food pantry two weeks before she was found dead. “Catherine was so timid,” she said. “I couldn’t believe anyone would want to hurt her.” A close relative, who asked not to be named to protect her privacy, said Saterfield-Buchanan always made sure you had something to eat. Red was her favorite color, she said. Occasionally, you could find her listening to rhythm and blues, but she mostly stuck to jazz. Erin Hooley / Chicago Tribune A Chicago police officer investigates where Catherine Saterfield-Buchanan was found dead with blunt force trauma to the face and defensive wounds on her body in the 3500 block of West Huron Street on June 22, 2017, in the East Garfield Park neighborhood of Chicago. A Chicago police officer investigates where Catherine Saterfield-Buchanan was found dead with blunt force trauma to the face and defensive wounds on her body in the 3500 block of West Huron Street on June 22, 2017, in the East Garfield Park neighborhood of Chicago. (Erin Hooley / Chicago Tribune) (Erin Hooley / Chicago Tribune) The night Saterfield-Buchanan was killed, the relative spoke with her on the phone about a Fourth of July barbecue. “I love you,” Saterfield-Buchanan told her. “Tell the kids I love them.” Two hours later, she was killed. The relative said detectives did not interview her or other immediate family members who knew about Saterfield-Buchanan’s whereabouts. “You tellin’ me they got away?” the relative said. “She was a nice, caring person.” Staples, the chief of detectives, said investigative notes show detectives did interview a relative, though the family says it was a cousin who was not close to Saterfield-Buchanan. Massonburg said she doesn’t recall talking to police about Saterfield-Buchanan, even though the shelter is known for helping women in the sex trade on the West Side. Massonburg believes police should regularly visit her shelter — something they don’t do now — and get to know the women, build trust and maybe collect leads to solve some of the cases. “People know what’s happening (on the street),” Massonburg said. “But they don’t talk because they don’t feel protected.” ‘Where were you?’ The same unease can grip neighborhoods where the women have been discovered. In 2014, Velma Howard was found frozen in the snow in East Garfield Park. On the block where she was discovered, an elderly man recently answered his door, scrunched his face and jutted out his chin at the mention of the slaying. “Why are you here?” he barked. “Three years later? After all this time? Where were you?” He shook his head and slammed the door. His son, who lives in the apartment below him, came outside and talked to the reporters. Yes, he said, they remember when the body was found, buried in a snowbank. Official reports tell the story in vivid detail: Howard wore two white socks on her left foot, one on her right foot, and a metal hoop earring hung from her left earlobe. Black leggings were under her jeans, and a cigarette lighter and napkin were tucked into the left front pocket of her pants. Her fingernails were painted blue, and her toenails were red. With the temperature near freezing, she bundled herself in a blue sweatshirt and brown jacket. It wasn’t until the snow was shoveled that her body was discovered wrapped in a tan blanket, tied together with a red rope. A white electrical cord was wrapped around her neck so tightly, purple bruising was visible. The son explained to a reporter why his dad was so upset: Neither he nor his dad was interviewed by police. “They just picked the body up and left,” the son said. “We (are) just looked over.”
Neither man wanted to be named. The department would not allow the newspaper to see the files on Gomez, Saterfield-Buchanan, Howard or the other women because the cases are considered open and still active. But Staples said she personally reviewed 15 of the unsolved cases and referred three to cold case detectives. Staples would not disclose which cases, saying she wanted to protect any new investigative work. ‘They deserve the same investigation as anyone else’ Staples sits in her fourth-floor office at Chicago police headquarters on the South Side, a 4-inch stack of case files to her left. She came up through the ranks of the detective division and has worked cases in neighborhoods where some of the women were found dead. They are tragic and tough cases to solve, she acknowledged. Like other murder cases, they are assigned to the regular rotation of homicide detectives in the city’s three major investigative divisions. There are teams of specialists for sex-related crimes. As in any homicide, detectives canvass for witnesses, talk to family members and draw on help from the department’s vice unit and its human trafficking team when investigating the cases. DNA and other evidence are collected and sent to the Illinois state crime lab. If a DNA profile is obtained, it is entered into a national database called CODIS. It contains samples from arrested felons as well as unnamed samples from victims and crime scenes. In that way, cases can be matched even when a suspect is not known. In the 51 unsolved cases found by the Tribune, no such case-to-case associations have been found, Staples said. And no cases have been linked by other investigative means. In the 1990s, Chicago police were caught off-guard when DNA analysis detected at least four patterns of sexual assaults and slayings of prostitutes in several South Side neighborhoods. The Tribune account in a 2000 story outlined the problem in terms strikingly similar to those of Gomez, Saterfield-Buchanan, Howard and the others: Most of the victims were strangled or suffered blunt force trauma. Many had arrests for drugs and prostitution and were engaged in what police at the time called a “high-risk lifestyle.” A task force was created to investigate dozens of rapes and murders. It was staffed by about 10 detectives who could dedicate their time to tracking down witnesses and reviewing DNA results. Officials at the time pledged to stay vigilant and continue to use it when appropriate. "Years ago, nobody cared about these girls,” Sgt. Tony Kuta said at the time. “Well, they're homicide victims. They're people, citizens of Chicago and they deserve the same investigation, the same integrity of investigation as anyone else.” Staples and other department officials said they did not know what happened to the task force over the years. She doesn’t think one is needed now, believing the nature of the crimes and the troubled backgrounds of the victims can be handled by detectives on regular duty. “It’s all evidence and witnesses,” she said. Nancy Stone / Chicago Tribune Margaret Gomez's body was found in this industrial area near the Stevenson Expressway in the 4200 block of South Knox Avenue in Chicago. Margaret Gomez's body was found in this industrial area near the Stevenson Expressway in the 4200 block of South Knox Avenue in Chicago. (Nancy Stone / Chicago Tribune) (Nancy Stone / Chicago Tribune) But some outside experts and law enforcement officials think a task force or other kind of stepped-up effort is needed, both to watch for serial killers and to clear up the backlog of strangulations at a time when detectives are burdened by a spike in gang killings. There were 670 homicides in Chicago last year and 792 the year before, the most in nearly two decades, according to data kept by the Tribune. Many of those were fatal shootings involving gangs. “We are talking a lot about gun violence in the city of Chicago because we should, because we have a ridiculous amount of gun violence in this city,” State’s Attorney Foxx told the Tribune. Asked if a task force could help, Foxx said such collaboration between her office and police could increase clearance rates by focusing more attention on the cases and detecting possible patterns. She noted that her office already has staff that specializes in human trafficking. “I think sometimes we forget that we can walk and chew gum at the same time,” Foxx said. “There has to be sustained advocacy around women who are losing their lives because they are vulnerable.” Jody Raphael, a researcher at DePaul University who has studied prostitution in Chicago for years, said the number of unsolved cases is a reminder how much time and resources these crimes demand. “Because of the fact that you could have a serial murderer out there, you have to investigate these cases,” Raphael said. “It could be weeks and weeks of pounding the pavement and very hard work.” ‘I know you got some dreams’ Researchers across the country are trying to better understand violence against people who work in prostitution and how to reduce it. While serial killings are declining in this country, they are decreasing at a slower rate when the victims are prostitutes. “The likelihood of being a victim of serial murder has declined for everyone,” said Kenna Quinet, an associate professor in the School of Public and Environmental Affairs at Indiana University-Purdue University at Indianapolis. “But it hasn’t as much for prostitutes. They are unable to protect themselves. … The nature of their work is they will go with a stranger. That it is illegal forces it into an underground and invisible economy.” One study found that 65 percent of serial murder victims were female, and nearly 78 percent of them were prostitutes. Morris Hoffer, from the Chicago Alliance Against Sexual Exploitation, said all this points to an obvious law enforcement approach: Make it riskier for men to prey on these women. “They should be aggressively going after men who buy sex,” Morris Hoffer said. “People think about the prostitution as a problem about her, but prostitution is a problem about him. … Culturally if we could flip the focus and stop saying the question is the choices or the behaviors that she is engaging in and think about the choices and behaviors of the buyers. … Most men don’t buy sex. We have to move toward judging and condemning and penalizing the men whose disposable income fuels this entire thing.” While some have argued for more cameras in areas frequented by customers, others have pressed for more outreach and social services to keep the women off the streets. “We are the ones that are actually in the belly of the beast,” said Stephanie Daniels-Wilson, who co-founded Dreamcatcher with Myers-Powell. “And crisis doesn’t make an appointment. We are in the street doing this.” Nancy Stone / Chicago Tribune Brenda Stewart, executive assistant at The Dreamcatcher Foundation, visits friends at Hody's Grill in Cicero as she goes on her route helping prostitutes. Stewart and fellow Dreamcatcher worker Tracey Whitney, both former prostitutes, spent their night Oct. 5, 2017, driving all over the city of Chicago searching for prostitutes to hand out comforting words and toiletry kits. Brenda Stewart, executive assistant at The Dreamcatcher Foundation, visits friends at Hody's Grill in Cicero as she goes on her route helping prostitutes. Stewart and fellow Dreamcatcher worker Tracey Whitney, both former prostitutes, spent their night Oct. 5, 2017, driving all over the city of Chicago searching for prostitutes to hand out comforting words and toiletry kits. (Nancy Stone / Chicago Tribune) (Nancy Stone / Chicago Tribune) One night in early October, an eight-passenger van emblazoned with “Dreamcatcher Foundation” bounced along Marquette Road west, then north on Halsted Street as the clock edged toward midnight. The streets were empty. The van cruised up 47th Street and then over to the area known as K-Town on the West Side. ||||| CHICAGO (AP) — An investigation by the Chicago Tribune has found that at least 75 women have been strangled or smothered over the last 17 years, though arrests have been made in just a third of the cases.
The newspaper reports that the women's bodies were found in vacant buildings, alleys, garbage cans and snow banks. Many of the women struggled with drugs or prostitution, while some had no arrest records. Chicago police say they've found no evidence of a serial killer.
The newspaper's analysis of medical examiner records and public crime reports also found that the women ranged in age from 18 to 58 and most were African-American. Of the 75 cases, 25 have been closed with the arrests of 13 men. That leaves 67 percent unsolved.
Police wouldn't say if there are active suspects in those cases, but officials reviewed more than a dozen cases after being contacted by the newspaper and referred three to cold case detectives.
Autopsies show some women were also raped and beaten. Others were gagged, had plastic bags tightened around their heads, suffered severe head injuries and bruises over their bodies.
"The brutal nature of these crimes is very disturbing," Chief of Detectives Melissa Staples said.
The police department had formed a task force when the bodies of dozens of women were found in the late 1990s and early 2000s. The task force solved the slayings of 40 women, but it was eventually disbanded. Staples said she isn't sure the task force needs to be reinstated, but Cook County State's Attorney Kim Foxx said it was worth considering to raise the "level of urgency" in clearing cases.
Kaethe Morris Hoffer, executive director of the Chicago Alliance Against Sexual Exploitation, said it's a staggering number of cases.
"It is odd how easy it is to disrupt people's sense of comfort when a large number of people are all killed at once," she said. "It is likewise upsetting to realize how, if you spread out over a long period of time, how inured people are to the murdering of women, particularly marginalized women." | – An investigation by the Chicago Tribune has found that at least 75 women have been strangled or smothered over the last 17 years, though arrests have been made in just a third of the cases. The newspaper reports that the women's bodies were found in vacant buildings, alleys, garbage cans, and snow banks. Many of the women struggled with drugs or prostitution, while some had no arrest records. Chicago police say they've found no evidence of a serial killer. The newspaper's analysis of medical examiner records and public crime reports also found that the women ranged in age from 18 to 58 and most were African American. Of the 75 cases, 25 have been closed with the arrests of 13 men. That leaves 67% unsolved, reports the AP. Police wouldn't say if there are active suspects in those cases, but officials reviewed more than a dozen cases after being contacted by the newspaper and referred three to cold case detectives. Autopsies show some women were also raped and beaten. Others were gagged, had plastic bags tightened around their heads, and suffered severe head injuries. "The brutal nature of these crimes is very disturbing," Chief of Detectives Melissa Staples said. The police department had formed a task force when the bodies of dozens of women were found in the late 1990s and early 2000s. The task force solved the slayings of 40 women, but it was eventually disbanded. Staples said she isn't sure the task force needs to be reinstated, but Cook County State's Attorney Kim Foxx said it was worth considering to raise the "level of urgency" in clearing cases. |
This troublemaker was bound to chime in! Leah Remini revealed to ABC News on Thursday, April 28, that she encouraged Ron Miscavige, the father of Scientology leader David Miscavige, to write a memoir about his 40-plus years of experience in the church.
The King of Queens actress — who dominated headlines last November after releasing her own memoir, Troublemaker: Surviving Hollywood and Scientology — says she reached out to the elder Miscavige after he defected in 2012.
"I tracked him down," Remini, 45, recalled to ABC News in her new sit-down interview. "I called him and I offered my support, because I know he must've felt alone. I just wanted him to know that we were willing to take them in. Because there is no place for them to go unless they have family, which is very rare, outside of the church."
Vincent Sandoval/WireImage.com
Like Ron, Remini left the church after decades of service in 2013, and subsequently detailed her experiences as a Scientologist in her now bestselling memoir. Remini told ABC News that she "immediately" encouraged Ron to write a book about his intimate journey in the church. "Because his story is important," she disclosed. "We're all gonna speak up. You're not gonna just bully people telling their stories."
Ron took Remini's advice, and detailed his 40-year Scientology journey — 27 years specifically devoted to the church's mysterious Sea Org — in his upcoming memoir, Ruthless: Scientology, My Son David Miscavige, and Me. He will also open up to 20/20's Dan Harris about his son, David, in an interview airing Friday, April 29.
"He wasn't always that way," Ron said of David in a new preview. "When he was a kid, he was a lovable kid."
The church, in the interim, has slammed Ron and his upcoming book, calling it "literary forgery."
"There seems to be no explanation except that his father is trying to make a buck off his name," Scientology attorney Monique Yingling told ABC News. "So I think there's that level of sadness and I'm sure a sense of betrayal."
PIERRE-PHILIPPE MARCOU/AFP/Getty Images
Scientology expert Tony Ortega reported this week that the Church of Scientology is currently trying to legally halt the publication of the senior Miscavige's upcoming book. Lawyers from Johnsons Solicitors (on behalf of its client David Miscavige) contacted the U.K. publisher of Ruthless asking them to stop the book's release, arguing that it was "highly defamatory."
Ron's interview with ABC will air on 20/20 on Friday, April 29, at 10 p.m. ET. His memoir, Ruthless: Scientology, My Son David Miscavige, and Me, will be released on May 3.
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||||| Transcript for Leah Remini Offered Support to Father of Scientology Leader
We begin with the new headline about scientology. Leah remini speaking out yet again going public once more but this time to defend another high-profile explosive defector, the father of the all powerful leader of the church and author of the new book "Ruthless." ABC's Dan Harris is here with the latest. Good morning. Reporter: Good morning. This is a huge story inscientology circles. David miscavige sits atop one of the most controversial churches on Earth and now his own dad has quit scientology and written a book about his time in the church. Scientologist is hitting back hard and now Leah remini is entering the fray. This morning, Leah remini -- You are unbelievable. Reporter: The former star of "The king of queens" going to bat for a fellow ex-scientologist. He has a right to tell his story. Reporter: Ron miscavige, the father of the powerful leader of the church, David miscavige. If you were a scientologist you are one of the relative few that hold the answers in your possession that all humankind depend upon. Reporter: David miscavige bears the title of chairman of the board or cob and he was the best man at the wedding of Tom cruise and Katie Holmes. So I say to you, C.O.B., we are lucky to have you and thank you very much. Reporter: When word hit that David miscavige's own father, the now 82-year-old Ron miscavige had left the church after decades of service, Leah remini says it spread like wildfire. I tracked him down. I called him and I offered my support because I know he must have felt alone. I just wanted him to know that we were willing to take them in That's a big offer. What made you feel motivated to do that. Because there is no place for them to go unless they have family, which is very rare outside of the church. Did you encourage him at all to go public with his story? Yes, I mean I immediately said that he should write a book because his story is important. Reporter: Now Ron miscavige has written a book and he's speaking about it in an exclusive interview that will air on ABC's "20/20" on Friday night. You have written a whole book about your son and you've called the book "Ruthless". Yes. It is a pretty damning charge to level against your child in he wasn't always that way. When he was a kid, I am telling you, he was a lovable kid. Reporter: A lovable kid who according to his dad has let the power of being at the helm of this wealthy celebrity filled church go to his head. Ron miscavige's book is laden with charges that scientology is calling outright lies and it was co-authored by another former scientologist now a well-known critic of the church. It is not a memoir. It's in my view a literary for forgery. Reporter: But now Leah remini is stepping forward to defend Ron miscavige. We're all going to speak up. You're not going to just bully people telling their stories. Tomorrow right here on "Gma" you'll hear much more from Ron miscavige himself about why he left the church and the war within his own family right now and then, of course, our full report tomorrow night on "20/20." Fascinating stuff. It sure is. Cannot wait for the rest. We move on to it new clues
This transcript has been automatically generated and may not be 100% accurate. ||||| Ron Miscavige, the father of the Church of Scientology leader David Miscavige, claims the Church hired two private investigators, who followed him for over a year after he left the Church in 2012, to spy on him.
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In an exclusive interview with ABC News “20/20,” Ron Miscavige said he found out about the P.I.s after police in West Allis, Wisconsin, got a call about a man acting suspiciously.
According to the West Allis Police’s report on the incident, dated July 30, 2013, police questioned the man on the street and at first he told them he was looking into buying a house in the neighborhood. After they checked his wallet, the man was identified as Dwayne Powell, a private investigator from Florida, who then told police he was in the area “on a job,” the police report stated. Dwayne Powell said he and his son Daniel ran a private investigator firm together.
Police searched Powell’s rented SUV and inside they found an arsenal of hand guns, rifles, 2,000 rounds of ammunition, a stun gun, a GPS tracking device, a high zoom camera, a satellite computer, a bag of license plates for five different states, and what police said “appeared to be a rifle silencing device,” according to the police report.
“It sounds like he’s a hitman, doesn’t it?” Ron Miscavige told ABC News “20/20.”
West Allis Police officers, along with an ATF agent, brought Dwayne and Daniel Powell in for questioning and started tape recording the interrogation. According to the police report, when investigators asked Dwayne Powell who he was working for, Powell asked for the tape recorder to be turned off while he named his employers, which the investigators said they did and continued to write down Powell’s statements for the report.
“He stated that he was hired by the CA based Church of Scientology to conducted [sic] full time surveillance of a Ronald Miscavige,” the report said, adding that Powell said he was being paid by attorneys for the Church, “and that the main client is a David Miscavige.”
According to the police report, Dwayne Powell said there was an incident earlier that month when he saw Ron Miscavige grab his chest outside of a Wisconsin grocery store parking lot and he called the Church’s attorneys, thinking Ron might be having a heart attack.
Dwayne Powell “stated that he was called about two minutes later by a man who identified himself as David Miscavige,” the police report said. “David told him that if it was Ron’s time to die, to let him die and not intervene in any way. He stated that this is the only time that he has ever spoken to David Miscavige and that he has never met him.”
Investigators questioned Daniel Powell and tape recorded the entire interrogation. During questioning, Daniel Powell said his father Dwayne had been a private investigator for the Church for nine years and denied they were there to harm Ron Miscavige, according to the police report. Daniel told police he and his father were “sport shooters,” which is why they had firearms and ammunition in their rented SUV.
Daniel told police that he remembered the incident when his father Dwayne Powell thought Ron Miscavige was having a heart attack and said his father “called his contact and reported it,” according to the police report.
“A couple minutes later, his dad told him that David Miscavige called him directly and told him not to intervene and let Ron die if it was his time,” the police report said.
Ron Miscavige told ABC News he remembered the “heart attack” moment, and said he was just reaching for his cellphone in his shirt pocket that day. When he heard his son had allegedly said that about him, he said it felt like a “shot to the head” and he said it lead him to believe that his son David felt his “position in the church and his public relations and his image meant more to him than a father.”
Monique Yingling, a lawyer for the Church of Scientology, acknowledged in an interview with ABC News that lawyers for the Church had hired the private investigators to follow Ron Miscavige, but said David Miscavige did not know about the hiring of the private investigators to follow his father, never spoke to them, and had nothing to do with them.
“There wasn't any reason to tell him [David Miscavige]” about the investigators, Yingling said. “They [the Church’s attorneys] decided that the private investigators were following Ron, first of all, for his own well-being and his own safety. They were also concerned that he might somehow, because he was an elderly man with David's name, become the pawn of some of the anti-Scientologists out there.”
“Lawyers use private investigators all the time for, you know, varieties of reasons, and it's just no big deal,” she added.
She also said in her interview that the West Allis Police mistakenly combined Dwayne Powell’s story with his son’s story when they stopped tape recording Dwayne and took down notes by hand, and what his son Daniel told police about David Miscavige calling them was incorrect.
“It's not true, and Dwayne Powell has said that it's not true,” Yingling told “20/20.”
The Church produced a signed statement from Dwayne Powell, saying he never spoke to David Miscavige and that both the police and his son Daniel got the report wrong.
“Certain statements I allegedly made to the West Allis Police Department have been misinterpreted. I have never communicated orally or in writing, directly or indirectly, with Mr. David Miscavige,” said Powell’s statement from the Church. “I never met him. I never received any instruction or directions from him directly or indirectly. David Miscavige never was my client. The statement made in a West Allis Police Report that I received a call from a man who identified himself as David Miscavige is not correct. I did not make such a statement to police.”
“Statements made by my son, Daniel, to the West Allis Police Department asserting that I spoke to David Miscavige and that David Miscavoige said not to intervene and to let Ronald T. Miscavige die are not true,” the statement continued.
The West Allis Police Department told ABC News in a statement that they stand by their report.
“The reports which have been authored by West Allis Police Officers and Detectives accurately reflect the statements of Dwayne and Daniel Powell on July 29, 2013,” the statement said. “There is no confusion in the statements that were made by Dwayne and Daniel Powell. Dwayne and Daniel Powell were interviewed independently of one another, and their statements corroborated one another. The ‘Declaration of Dwayne Powell’ dated August 7, 2015 directly contradicts statements which Dwayne Powell made to members of the West Allis Police Department in July of 2013.”
Ron Miscavige wrote a memoir, “Ruthless: Scientology, My Son David Miscavige, and Me,” with Dan Koon, a former Church official who is now a vocal critic. It's out in stores on May 3. | – Actress Leah Remini, who knows a thing or two about Scientology memoirs, says she prompted the father of Church of Scientology leader David Miscavige to write his own memoir, which is slated to be published May 3, Us Magazine reports. "His story is important," Remini tells ABC News. "We're all gonna speak up. You're not gonna just bully people telling their stories." Ron Miscavige spent more than 40 years with the Church of Scientology—27 of them with Sea Org—before leaving in 2012. "I called him and I offered my support because I know he must've felt alone," Remini says. The church is attempting to block the publishing of Ruthless: Scientology, My Son David Miscavige, and Me, which it calls a "literary forgery" and blatant attempt to make money. In addition to the memoir, Ron Miscavige gave an exclusive interview to 20/20 scheduled to air Friday. In a preview published by ABC News, he says he was spied on by private investigators for two years after leaving the church. At one point, police contacted one of the PIs and found rifles, handguns, ammunition, and multiple license plates in his SUV. “It sounds like he’s a hitman, doesn’t it?” Miscavige asks 20/20. Police say one of the PIs was told by David Miscavige to "let him die" if Ron was to have any sort of medical emergency. Ron Miscavige says it felt like a "shot to the head" to hear his own son say that. |
the knowledge of the properties of highly compressed and heated hadronic matter is an important issue for the understanding of astrophysics such as the physical mechanism of supernovae explosions and the physics of neutron stars @xcite .
hic provide the unique opportunity to explore highly excited hadronic matter , i.e. the high density behavior of the nuclear eos , under controlled conditions ( high baryon energy densities and temperatures ) in the laboratory @xcite .
important observables have been the nucleon collective dynamics @xcite and the dynamics of produced particles such as pions and kaons @xcite
. however , the reaction dynamics is a rather complex process which involves the nuclear mean field ( eos ) and binary @xmath2-body collisions . in the presence of the nuclear medium the treatment of binary collisions represents a non - trivial topic .
the nn cross sections for elastic and inelastic processes , which are the crucial physical parameters here , are experimentally accessible only for the free space and not for @xmath2-body scattering at finite baryon density .
recent microscopic studies , based on the @xmath3-matrix approach , have shown a strong decrease of the elastic nn cross section @xcite in the presence of a hadronic medium .
these in - medium effects of the elastic nn cross section considerably influence the hadronic reaction dynamics @xcite .
obviously the question arises whether similar in - medium effects of the _ inelastic _ nn cross sections may affect the reaction dynamics and , in particular , the production of particles ( pions and kaons ) .
since microscopic results are not available , we discuss here in a simple phenomenological way possible density modifications of the inelastic nn cross sections and their influences on particle multiplicities , rapidity distributions and ratios .
we find a strong dependence of the yields and rapidity distributions on the in - medium modifications of the inelastic cross sections , but on the other hand , this effect is only moderate for particle ratios such as @xmath0 , and almost vanishes for @xmath1 .
therefore such ratios turn out to be robust observables in determining the nuclear eos and , particularly , the isovector channel of the nuclear mean field @xcite .
in this chapter we briefly discuss the transport equation by concentrating on the treatment of the cross sections , which are the important parameters of the collision integral .
the theoretical description of hic is based on the kinetic theory of statistical mechanics , i.e. the boltzmann equation @xcite .
the relativistic semi - classical analogon of this equation is the relativistic boltzmann - uehling - uhlenbeck ( rbuu ) equation @xcite @xmath4 f(x , k^ { * } ) = \frac{1}{2(2\pi)^9 } \nonumber\\ & & \times \int \frac{d^3 k_{2}}{e^{*}_{{\bf k}_{2 } } } \frac{d^3 k_{3}}{e^{*}_{{\bf k}_{3 } } } \frac{d^3 k_{4}}{e^{*}_{{\bf k}_{4 } } } w(kk_2|k_3 k_4 ) \left [ f_3 f_4 \tilde{f}\tilde{f}_2 -f f_2 \tilde{f}_3\tilde{f}_4 \right ] \label{rbuu } \end{aligned}\ ] ] where @xmath5 is the single particle distribution function . in the collision term
the short - hand notation @xmath6 for the particle and @xmath7 and the hole - distribution is used .
the collision integral exhibits explicitly the final state pauli - blocking while the in - medium scattering amplitude includes the pauli - blocking of intermediate states .
( 8.,7.3 ) ( 3.0,0.3 ) the dynamics of the lhs of eq.([rbuu ] ) , the drift term , is determined by the mean field . here
the attractive scalar field @xmath8 enters via the effective mass @xmath9 and the repulsive vector field @xmath10 via kinetic momenta @xmath11 and via the field tensor @xmath12 .
the in - medium cross sections enter into the collision integral via the transition amplitude @xmath13 with @xmath3 the in - medium scattering matrix element . in the kinetic equation ( [ rbuu ] ) one should use both physical quantities , the mean field ( eos ) and the collision integral ( cross sections ) according to the same underlying effective two - body interaction in the medium , i.e. the in - medium t - matrix ; @xmath14 , respectively @xmath15 .
however , in most practical applications phenomenological mean fields and cross sections have been used . in these models adjusting the known bulk properties of nuclear matter around the saturation point one tries to constrain the models for supra - normal densities with the help of heavy ion reactions @xcite .
medium modifications of the nn cross section are usually not taken into account which works , in comparison to experimental data , astonishingly well @xcite .
however , in particular kinematics regimes a sensitivity of dynamical observables such as collective flow and stopping @xcite or transverse energy transfer @xcite to the elastic nn cross section has been observed .
( 8.,7.3 ) ( 3.0,0.3 ) fig .
[ fig1 ] shows the energy dependence of the in - medium neutron - proton @xmath16 cross section at fermi momenta @xmath17 , corresponding to @xmath18 ( @xmath19 is the nuclear matter saturation density ) as found in relativistic dirac - brueckner ( db ) calculations @xcite .
the presence of the medium leads to a substantial suppression of the cross section which is most pronounced at low laboratory energy @xmath20 and high densities where the pauli - blocking of intermediate states is most efficient . at larger @xmath20
asymptotic values of 15 - 20 mb are reached . however , not only the total cross section but also the angular distributions are affected by the presence of the medium .
the initially strongly forward - backward peaked @xmath21 cross sections become much more isotropic at finite densities @xcite which is mainly do to the pauli suppression of soft modes ( @xmath22-exchange ) and correspondingly of higher partial waves in the t - matrix @xcite .
obviously one expects similar in - medium effects for the inelastic nn cross sections mainly due to pauli - blocking of intermediate scattering states and in - medium modified matrix elements .
such microscopic studies for inelastic processes are very rare or still in development @xcite . however , to explore the sensitivity we use here a rather simple parametrization which assumes a reduction of the inelastic nn cross section with increasing baryon density , in line with that of fig .
[ fig1 ] for the elastic one which has previously been used in ref .
this can be achieved by assuming a factorization of the effective matrix element of the form @xmath23 with @xmath24 the vacuum matrix element ( taken from experimental free scattering data ) and @xmath25 a density dependent function depending on a quenching parameter @xmath26 .
a very simple parametrization of the function @xmath27 is shown in fig .
[ fig2 ] ( bottom panel ) for different values of the parameter @xmath26 .
the effect on the inelastic nn cross section is shown on the top of fig .
[ fig2 ] for the choice @xmath28
. a significant reduction of the effective inelastic nn cross section ( by a factor of 2 ) is observed with respect to that of the free case at a given baryon density @xmath29 .
we have applied the parametrization ( [ meff ] ) in the collision integral of the transport equation ( [ rbuu ] ) and analyzed the transport calculations in terms of particle production . at energies below 1.6 agev pions and kaons
are produced , where the second ones do not significantly affect the reaction dynamics due to their small production cross sections .
in particular , the kaons are treated perturbatively and can be produced from @xmath30 and @xmath31 .
here @xmath32 stands for a nucleon or @xmath33 resonance and @xmath34 for a hyperon .
pions are created via the decay of the @xmath35 resonance . for more details
we refer to @xcite . for the nuclear mean field the @xmath36 parametrization of the non - linear walecka model @xcite
is adopted here with a compression modulus of @xmath37 mev and an effective dirac mass of @xmath38 ( @xmath39 is the bare nucleon mass ) .
the momentum dependence enters via the relativistic treatment through the vector components of the baryon self energy . in order to keep the discussion transparent
, we do not apply here any isovector components of the baryon self energy , as it has been previously done in ref .
this implies no effective mass splitting between protons and neutrons , and on the other hand , between the different isospin states of the @xmath33 resonance ( @xmath40 ) and of the hyperons ( @xmath41 ) .
furthermore , pions are propagated in a coulomb field and kaons do not experience any potential .
( 3.0,0.3 ) we start the discussion with the time evolution of the multiplicities of the @xmath33 resonances and of the pions , as can be seen in fig .
the time evolution of the multiplicity of produced @xmath33-resonances is shown with their maximum around 15 fm / c which corresponds to the time of maximum compression .
due to the finite lifetime these resonances decay into pions ( and nucleons ) according @xmath42 ( some of these pions are re - absorbed in the inverse process , i.e. @xmath43 ) .
this mechanism continues until all resonances have decayed leading to a final constant pion yield for times @xmath44 fm / c ( the so - called freeze - out time ) .
after the freeze - out the pions can be measured experimentally .
the experimental pion multiplicity is schematically shown in fig .
[ fig2 ] by the gray band for central au+au collisions @xcite .
we observe an essential reduction of the pion multiplicity using the effective inelastic nn cross sections , in line with the previous fig .
[ fig2 ] . as an important result the calculations with the effective inelastic nn cross section describe the experimental data reasonably well for a quenching parameter of about @xmath28 . however , for a more realistic comparison one should use more microscopic calculations of the inelastic cross section , as it has been done in ref . @xcite .
such a progress is under study .
the strong in - medium dependence of the inelastic cross sections is shown also in the rapidity distributions of pions and kaons in fig .
[ fig4 ] .
( 3.0,0.3 ) the rapidity distribution of kaons is even more stronger affected by the density behavior of the inelastic cross section with respect to that of pions .
this is due to the fact that the leading channels for kaon production are @xmath45 and pionic ones , which are both reduced when the in - medium dependent @xmath46 are used .
the question arises whether particle ratios are influenced by in - medium effects of the inelastic cross section .
an answer on this question is of major importance , particularly for kaons and less for pions , since particle rations have been widely used in determining the nuclear eos at supra - normal densities .
relative ratios of kaons between different colliding systems have been used in determining the isoscalar sector of the nuclear eos , see refs .
more recently , the @xmath0- and @xmath1-ratios have been used in exploring the high density behavior of the symmetry energy , i.e. the isovector part of the nuclear mean field @xcite .
.in - medium dependence of the @xmath0- and @xmath1-ratios for central ( @xmath47 fm ) au+au collisions at 1.48 agev incident energy .
[ cols="^,^,^",options="header " , ] table [ table1 ] shows the @xmath0- and @xmath1-ratio for central ( @xmath47 fm ) au+au collisions at 1.48 agev incident energy using both , the free and in - medium inelastic cross sections .
the pionic ratio moderately depends on the density dependence of the inelastic cross section , but the @xmath1-ratio is not particularly affected by the in - medium effects . a possible reason for the different behavior between the pionic and kaonic ratios may be the fast pre - equilibrium emission of the kaons .
in particular , kaons are created very early during the formation of the high density phase and are emitted from the compression region without undergoing any interaction with the hadronic environment .
therefore one obviously expects a direct relation between the high density effects of the inelastic cross sections and the @xmath1-ratio .
pions , on the other hand , are strongly interacting with the medium via secondary re - absorption processes and thus are emitted from different stages of a collision which may influence the final @xmath0-ratio @xcite .
it turns out that the strangeness ratio presents a robust observable to investigate the isovector character of the nuclear matter eos .
we have investigated the role of the density dependence of the inelastic cross section on particle production in intermediate energy heavy ion collisions within a covariant transport equation of a boltzmann type . since microscopic studies on the in - medium behavior of inelastic cross sections are still rare , we have used here a simple phenomenological in - medium dependence of the inelastic cross sections .
we have applied the transport equation to au+au collisions at intermediate relativistic energies below the kaon threshold energy .
our studies have shown a strong sensitivity of the particle multiplicities and rapidity distributions of pions and kaons .
in particular , a reduction by a factor of @xmath2 for pions has been seen when the in - medium effects in the inelastic cross section are accounted for .
consequently , the kaon ( @xmath48 ) yields decrease more than 50 % .
this is due to the asumption of a reduction of the inelastic cross section at high densities . as an interesting
finding , the multiplicities of @xmath49 and @xmath50 are influenced in such a way that their ratio is independent on the density dependence of the inelastic cross sections .
this may be due to the long mean free path of the @xmath48 , whereas the pionic ratio , due to their strong secondary interaction processes with the hadronic environment , have shown a moderate dependence on the density behavior of the inelastic cross sections .
certainly more systematic studies are necessary to investigate better the mechanism which leads to a moderate relation between the in - medium dependence of the inelastic cross sections and the pionic ratio .
a comparison with more experimental data would be helpful in determining more precisely the density dependence of the inelastic cross sections , which will be an object of future studies . on this level of investigations
we conclude that the @xmath1-ratio represents a robust observable in determining the nuclear matter eos at supra - normal densities .
+ _ acknowledgment _ this work is supported by bmbf , grand 06lm189 .
one of the authors ( v.p . ) would like to thank h.h .
wolter and m. di toro for the warm hospitality during her short stays at their institutes .
www99 t. gaitanos , c. fuchs , h.h .
wolter , phys .
lett . * b609 * ( 2005 ) 241 ; + e. santini , t. gaitanos , m. colonna , m. di toro , nucl . phys . *
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wolter , prog .
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* 53 * ( 2004 ) 45 . | the in - medium modification of nucleon - nucleon ( nn ) cross sections is investigated by means of particle production in heavy ion collisions ( hic ) at intermediate energies .
in particular , the density dependence of the _ inelastic _ cross sections considerably affects the pion and kaon yields and their rapidity distributions .
however , the @xmath0- and @xmath1-ratios depend only moderately on the in - medium behavior of the inelastic cross sections .
it turns out that particle ratios seem to be robust observables in determining the nuclear equation of state ( eos ) and , particularly , its isovector sector . |
je thanks for hospitality during his stay at texas a&m university . this research is supported by the air force office of scientific research , darpa - quist , office of naval research , and the tamu telecommunication and informatics task force ( titf ) initiative .
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a * 72 * , 013820 ( 2005 ) . | precision measurement of small separations between two atoms or molecules has been of interest since the early days of science . here , we discuss a scheme which yields spatial information on a system of two identical atoms placed in a standing wave laser field .
the information is extracted from the collective resonance fluorescence spectrum , relying entirely on far - field imaging techniques .
both the interatomic separation and the positions of the two particles can be measured with fractional - wavelength precision over a wide range of distances from about @xmath0 to @xmath1 .
the measurement of small distances is a fundamental problem since the early days of science .
it has become even more important due to recent interest in nanoscopic and mesoscopic phenomena @xcite .
starting from the invention of the optical microscope around 400 years ago , today s optical microscopy methodologies can basically be divided into lens - based and lensless imaging . in general ,
far - field imaging is lens - based and thus limited by criteria such as the rayleigh diffraction limit which states that the achievable resolution in the focus plane is limited to half of the wavelength of illuminating light .
further limitation arises from out - of - focus light , which affects the resolution in the direction perpendicular to the focal plane .
many methods have been suggested to break these limits @xcite .
lens - based techniques include confocal , non - linear femtosecond or stimulated emission depletion microscopy @xcite .
also non - classical features such as entanglement , quantum interferometry or multi - photon processes can be used to enhance resolution @xcite .
a particularly promising development is lensless near - field optics , which can achieve nanometer spatial resolution @xcite . roughly speaking
, the idea is to have light interactions close enough to the object to avoid diffraction .
this , however , typically restricts near - field optics to objects on a surface . in 1995 , betzig proposed a method to reach sub - wavelength resolution that is not limited to one spatial dimension by assuming non - identical , individually addressable objects @xcite .
subsequently , this was realized in a landmark experiment of hettich et al .
@xcite .
it combined near - field and far - field fluorescence spectroscopy techniques , using the fluorescence spectrum to label different molecules inside an inhomogeneous external electrical field .
they also noticed dipole - dipole interactions between adjacent objects @xcite and used it to correct the measurement result .
however , there is still great interest in achieving nanometer distance measurements by using optical illuminating far - field imaging only .
( color online ) two atoms in a standing wave field separated by a distance @xmath2 smaller than half of the wavelength @xmath3 of the driving field .
the distance of the two atoms is measured via the emitted resonance fluorescence.,width=302 ] in this communication , we propose a scheme to measure the distance between two adjacent two - level systems by driving them with a standing wave laser field and measuring the far field resonance fluorescence spectrum , which is motivated by the localization of single atom inside a standing wave field @xcite . in particular , we focus on distances smaller than the rayleigh limit @xmath1 .
our basic approach is that in a standing wave , the effective driving field strength depends on the position of the particles .
thus , each particle generates a sharp sideband peak in the spectrum , where the peak position directly relates to the subwavelength position of the particle .
as long as the two sideband peaks can be distinguished from each other , the position of each particle can be recovered . however , when the interatomic distance decreases , the two particles can no longer be considered independent . due to the increasing dipole - dipole interaction between the two particles ,
the fluorescence spectrum becomes complicated .
we find , however , that the dipole - dipole interaction energy can directly be extracted from the fluorescence spectrum by adjusting the parameters of the driving field
. since the dipole - dipole interaction energy is distance dependent , it yields the desired distance information .
we provide detailed measurement procedures and our estimates show that the scheme is applicable to inter - particle distances in a very wide range from @xmath1 to about @xmath4 .
our model system consists of two identical two - level atoms located at fixed points @xmath5 ( @xmath6 ) in a resonant standing wave laser field ( see fig .
[ fig - system ] ) .
the atomic transition frequency is @xmath7 .
the laser field has frequency @xmath8 , wavelength @xmath3 and wave vector @xmath9 .
we assume the two atoms to be arranged along @xmath10 .
the driving field rabi frequency of atom @xmath11 is @xmath12 , with @xmath13 .
we denote the raising ( lowering ) operator of the @xmath11th atom by @xmath14 ( @xmath15 ) . in the following
, we assume the transition dipole moments of the two atoms to be parallel and aligned perpendicular to the @xmath10 direction .
we also assume resonant driving , @xmath16 .
if the two atoms are far apart ( the distance between atom @xmath11 and @xmath17 @xmath18 ) , then they are independent , and the total master equation is given by the sum of the two single - particle master equations @xcite . if the two atoms come close , they dipole - dipole interact , causing a collective system dynamics .
this gives rise to a complex energy shift due to a virtual photon exchange between the two atoms .
the imaginary part of this shift corresponds to an incoherent coupling , whereas the real part shifts the energy of the collective states of the system .
the full collective master equation is given by @xcite @xmath19 - \sum_{i , j=1}^{2 } \gamma_{ij } \left ( [ s_i^+,s_j^-\rho ] - [ s_j^-,\rho s_i^+ ] \right ) \ , . \label{master}\end{aligned}\ ] ] the coherent evolution is governed by @xmath20 .
the free energy @xmath21 of the two atoms and the interaction with the driving laser field @xmath22 are the same as for two independent atoms .
the coherent energy shift of the collective states arises from the dipole - dipole interaction @xmath23 , which involves couplings of both atoms . for the considered geometry ,
the dipole - dipole interaction @xmath24 is given by @xmath25 the incoherent evolution first entails the independent spontaneous emission of the two atoms @xmath26 ( @xmath6 ) , as found for uncoupled atoms .
terms with @xmath27 ( @xmath28 ) are the incoherent dipole - dipole couplings , where @xmath29 for large distances , ( @xmath30 ) , we find @xmath31 and @xmath32 , where @xmath33 is the kronecker delta symbol . thus we recover the case of two independent atoms , as expected . for small distances ( @xmath34 ) ,
one finds maximum incoherent cross - coupling , and @xmath24 approaches the static dipole - dipole interaction , @xmath35 % [ 1 - 3\cos^2\alpha ] \
, , \qquad \gamma_{ij}\approx \gamma\ , .
\label{param - approx}\end{aligned}\ ] ] sample spectra for @xmath36 , @xmath37 , @xmath38 .
fixed distance @xmath39 ( solid lines ) and harmonic oscillation around @xmath39 ( dashed lines ) .
( a ) large separation case : @xmath40 . ( b ) intermediate separation , weak driving field : @xmath41 ( c ) as ( b ) , but strong driving field : @xmath42 ( d ) small separation : @xmath43.,width=302 ] our strategy is to identify the distance of the two atoms via the emitted resonance fluorescence .
we define @xmath44 as the unit vector in observation direction , and the observation angle @xmath45 as @xmath46 .
the total two - atom steady state resonance fluorescence spectrum @xmath47 up to a geometrical factor is given by @xcite @xmath48 where the subindex @xmath49 denotes the steady state .
in general , this resonance fluorescence spectrum is rather complicated @xcite .
the spectrum , however , simplifies considerably in limiting cases , where either the driving field rabi frequency or the dipole - dipole interaction dominates the dynamics .
this will be exploited in the following , where we present in detail a measurement procedure , which allows us to extract the distance between the two atoms and their positions relative to nodes of the standing wave field , both with fractional - wavelength precision .
the first step in the measurement sequence is to apply a standing wave laser field to the two atoms , which at an anti - node of the standing wave corresponds to a rabi frequency @xmath50 of a few @xmath51 .
depending on the relative separation of the atoms , different spectra can be observed . if the two atoms are well - separated ( about @xmath52 ) , then the dipole - dipole interaction is negligible . in this case
spectra as shown in fig .
[ sample - spectra](a ) are obtained .
the two sideband structures can be interpreted as arising from the ac - stark splitting due to @xmath53 and @xmath54 .
thus the sideband peak positions @xmath55 and @xmath56 can directly be related to @xmath53 and @xmath54 and therefore to the position of the two atoms relative to the standing wave field nodes .
consequently , we can obtain the distance @xmath39 .
within half a wavelength , however , in general two interatomic distances are possible for measured values of @xmath53 and @xmath54 ( see fig .
[ intermediate - peakpos](a , b ) ) @xcite .
an identification of the actual atomic positions is possible by changing the standing wave phase slightly , i.e. , shifting the positions of the ( anti- ) nodes . as shown in fig .
[ intermediate - peakpos](a , b ) , a combination of the possible positions for two different standing wave phases yields the actual separation . note that this complication is not present for nearby atoms , where the non - vanishing dipole - dipole energy allows to determine the distance directly . in fig .
[ sample - spectra](a ) , the distance of the two particles is @xmath57 .
from the spectrum accessible in experiments , the distance @xmath58 is obtained , if we allow for a total measurement uncertainty of about @xmath59 .
thus the actual and the measured distances match , and the @xmath59 uncertainty of the distance measurement corresponds to about @xmath60 .
( color online ) ( a , b ) obtaining the position of the two atoms via a phase shift of the standing wave field .
solid ( dashed ) lines show possible atom positions for given @xmath53 ( @xmath54 ) .
( a ) before , ( b ) after the phase shift . the only coinciding potential positions in ( a ) and ( b )
give the true atomic positions .
( c ) deviation @xmath61 of the doublet splitting @xmath62 from @xmath63 for the strong field , intermediate distance case .
@xmath64 , @xmath37 , and @xmath36 .
the positions of the atoms are @xmath38 ( solid ) , @xmath65 ( dashed ) , @xmath66 ( dotted ) .
, width=302 ] if the distance between the two atoms is intermediate ( about @xmath67 ) , then the initial weak field measurement in general yields a more complicated spectrum , see fig .
[ sample - spectra](b ) .
the reason is that then the dipole - dipole coupling and the driving field strength are comparable , and the two atoms are not independent .
in such a case , a quantitative interpretation of the spectrum is difficult .
however , increasing the rabi frequency @xmath50 leads to a spectrum as shown in fig .
[ sample - spectra](c ) .
the spectrum consists of a central peak , two inner sideband doublets , and two outer sideband doublets , each symmetrically placed around the driving field frequency @xmath8 .
the center positions of the inner and outer sideband doublets corresponds to the rabi frequencies @xmath53 and @xmath54 .
the sideband structures are split into doublets due to the dipole - dipole coupling of the two atoms . for large @xmath50 ,
the splitting approaches twice the energy @xmath24 , as shown in fig .
[ intermediate - peakpos](c ) .
thus the strong - field sideband doublet splitting directly yields @xmath24 and then the distance of the two atoms , via eqs .
( [ omega12]).for example , in fig . [ sample - spectra](c )
, the actual distance is @xmath68 . from the spectrum ,
a measurement would obtain @xmath69 , where again we have allowed for an uncertainty of about @xmath59 . from eq .
( [ omega12 ] ) , this yields a measured distance of @xmath70 , in good agreement with the actual value . on the other hand ,
comparing the center center positions of the inner and outer sideband doublets with @xmath50 , the positions of the individual atoms relative to standing wave field nodes can be obtained . for the setup in fig .
[ sample - spectra](c ) , we have @xmath71 , @xmath72 , @xmath73 . from the spectrum , using the above procedure , we obtain @xmath74 , @xmath75 , assuming a relative uncertainty of @xmath59 . from @xmath76 , this would yield a measurement result of @xmath77 , in good agreement with the actual position of the atoms . in the above two regimes
, the situation slightly complicates if both atoms are located near - symmetrically around a node or an anti - node . in this case , @xmath78 , such that the two sideband peaks ( or doublets ) overlap .
one way to resolve this is to adequately change the standing wave field phase . by this
, the symmetry can be lifted to give @xmath79 .
then the above procedure can be applied to yield the separation and positions .
if the two atoms are very close to each other ( distance @xmath80 ) , then the spectrum is dominated by the dipole - dipole interaction energy @xmath24 , which gives rise to sideband structure at each side of the fluorescence spectrum close to @xmath81 , and only weakly depends on the driving field . a typical spectrum for this parameter range is shown in fig .
[ sample - spectra](d ) .
as long as @xmath53 , @xmath54 , @xmath82 is satisfied , the sideband structures only have a small residual dependence on the rabi frequency .
thus , the sideband peak position @xmath83 can directly be identified with @xmath24 .
fig .
[ peakpos - small - distance](a ) shows the deviation of the sideband peak positions from @xmath24 versus the atomic separation distance for different rabi frequencies @xmath50 .
note that the effective rabi frequencies @xmath53 , @xmath54 also depend on the position of the first atom within the wavelength , with maximum values @xmath84 close to the anti - nodes . it can be seen that for weak @xmath85 , the experimentally accessible sideband peak position and @xmath24 coincide very well . with increasing rabi frequency , the deviation increases , until the driving field induces a splitting of the sideband peaks , indicated by the branching point in fig .
[ peakpos - small - distance](a ) . if the initial spectrum of the first measurement has insufficient signal - to - noise ratio , then the fluorescence intensity can be enhanced by increasing the driving field intensity .
note that due to the dependence of @xmath53 , @xmath54 on the position of the two atoms , different positions of the two atoms may require different laser field intensities .
it is also possible to extrapolate the result of several measurements to the driving field - free limit to increase the measurement accuracy .
deviation @xmath86 of the peak position @xmath83 from @xmath24 for closely - spaced atoms .
@xmath36 , @xmath37 , and ( a ) against the atomic separation .
@xmath38 , @xmath87 ( solid ) , @xmath88 ( dashed ) , @xmath89 ( dotted ) .
( b ) against the driving field rabi frequency .
@xmath90 , @xmath91 ( solid ) , @xmath92 ( dashed ) , @xmath93 ( dotted ) .
branches indicate splittings into two peaks.,width=302 ] via eqs .
( [ omega12 ] ) or ( [ param - approx ] ) , the measured @xmath24 can easily be used to obtain the interatomic separation .
the separation is measured with increasing accuracy in the region of large slope of @xmath24 vs @xmath39 . for maximum accuracy ,
eq .
( [ omega12 ] ) should be numerically solved for the separation . here
, we discuss the small separation limit eq .
( [ param - approx ] ) , and allow for a small uncertainty in @xmath24 ( @xmath94 ) .
we obtain @xmath95^{1/3 } \cdot[1 - \delta \omega_{12}/(3\omega_{12})]$ ] as the distance @xmath96 between the two atoms .
thus , the relative uncertainty of the final result is about 1/3 of the relative uncertainty of the measured @xmath24 .
consider , for example , the case shown in fig .
[ sample - spectra](d ) .
the actual distance is @xmath97 .
the measured dipole - dipole energy is @xmath98 , again with a relative measurement uncertainty of about @xmath59 . from eq .
( [ omega12 ] ) , the distance then evaluates to @xmath99 .
thus in this case , the uncertainty of the distance measurement would be about @xmath100 , i.e. , less than @xmath101 of the actual distance .
once the distance @xmath39 is known , the positions of the two atoms relative to nodes of the standing wave field can be obtained . for this
, we note from fig .
[ peakpos - small - distance](b ) that for otherwise fixed parameters the position of the branching point depends on the rabi frequencies @xmath53 , and thus on the position @xmath102 .
if in the experiment we increase @xmath50 up to the branching point , then the position of the atom pair relative to the field nodes can be deduced .
accurate analytic expressions for the position of the branching point , however , are involved , as the general expression of the fluorescence spectrum is complicated @xcite .
thus a numerical fit as shown in fig .
[ peakpos - small - distance](b ) should be used to evaluate @xmath102 .
finally , since for small distances the spectrum is almost independent to the driving field , the distance information can also be obtained using a travelling - wave field , which may be more convenient in practice .
the precise positioning of the atoms is limited by thermal or quantum position uncertainties @xcite .
we have simulated this effect by assuming a motional ground state harmonic oscillation with amplitude @xmath103 ( corresponding to a lamb - dicke parameter @xmath104 ) around the mean distance @xmath39 .
results averaged over this motion are shown with dashed lines in fig .
[ sample - spectra ] . for @xmath105 ,
the motion is negligible . with increasing ratio @xmath106 ,
the spectral peaks split up . in fig .
[ sample - spectra](d ) , two peaks emerge at the classical turning points of the distance oscillation . from these , the mean distance can again be obtained .
the possible separation measurement range is limited , as the dipole - dipole coupling @xmath24 increases with decreasing separation as @xmath107 . for our model to remain valid , however ,
@xmath108 should be fulfilled . from eq .
( [ param - approx ] ) , for @xmath109 hz , @xmath110 hz , we estimate @xmath111 as the theoretical resolution limit .
this limitation only applies to the distance of the two atoms itself ; the distance uncertainty in principle can be well below @xmath112 . note that these considerations neglect experimental uncertainties , and are subject to imperfections e.g. in the measurement of laser field parameters or the alignment of dipole moments or laser fields . in summary , we have discussed a microscopy scheme entirely based on optical far - field techniques .
it allows to measure the separation between and the position of two nearby atoms in a standing wave laser field with fractional - wavelength precision over the full range of distances from about @xmath0 up to the rayleigh limit @xmath1 . |
the relation between classical optics and quantum optics is a fundamental topic in modern physics .
the notion of nonclassicality has been introduced by titulaer and glauber as the impossibility to describe optical field correlations of a specific state of light in terms of classical electrodynamics @xcite .
therefore , nonclassical states are the prerequisite of quantum effects , which are of great interest in quantum optics and quantum information . the definition of nonclassicality is based on the glauber - sudarshan phase - space representation of a quantum state @xmath1 , @xmath2 where @xmath3 denote the well - known coherent states @xcite . in general
, @xmath4 is a quasiprobability .
if it has the properties of a classical probability distribution , the state @xmath5 is a statistical mixture of coherent states , which are closely related to the classical behavior of the oscillator .
conversely , a state is referred to as nonclassical if the @xmath0 function shows some negativities .
however , for many states , already for the single - photon state , this quantity is highly singular . only in a few cases ,
when @xmath4 does not show singularities , it may be accessible from experimental data .
single - photon added thermal states ( spats ) belong to such a class of states @xcite , so that their @xmath0 function could be reconstructed for some parameters @xcite .
due to the singularities of the @xmath0 function , several different nonclassicality criteria have been developed .
simple inequalities often set bounds for classical states , which are violated for certain nonclassical states ; we only mention bounds on moments , such as ( higher - order ) squeezing @xcite , and probability distributions @xcite
. however , violation of these criteria is only sufficient , but not necessary for verifying nonclassicality . on the other hand ,
there are complete hierarchies of criteria , often based on matrices of moments @xcite or characteristic functions @xcite .
however , nobody is able to check such hierarchies completely , and practical application becomes involved for large matrices . in @xcite ,
a novel approach for nonclassicality detection was developed , which was based on phase - space methods .
it has been shown that for any nonclassical state , there exists a so - called nonclassicality quasiprobability which illustrates the nonclassical property by negativities .
moreover , it was shown that a family of nonclassicality distributions , parameterized by a real filter width @xmath6 , enables one to decide whether a state is nonclassical or not .
if a state is nonclassical , one can always find some finite filter width @xmath6 , such that the nonclassicality is observable as a negativity of the corresponding nonclassicality quasiprobability .
our method is suitable for experimental application , since it incorporates correct handling of statistical uncertainties .
moreover , it does not require precognition about the state . in the present paper we demonstrate , by experimental application , the capability of the method .
we examine single - photon added thermal states , whose @xmath0 function could be reconstructed for a sufficiently large mean thermal photon number @xcite . here
we overcome the problems occurring for arbitrary mean photon numbers , and therefore demonstrate the universality of the method of nonclassicality quasiprobabilities .
the paper is structures as follows : in section ii , we briefly review the approximate reconstruction of the @xmath0 function of a spats and its limitations for relatively small mean photon numbers . in section iii , we discuss the concept of nonclassicality quasiprobabilities and apply it to experimental data . eventually in section iv , we consider the role of the quantum efficiency on the detection of nonclassicality .
a summary and some conclusions are given in section v.
let us briefly recall the reconstruction of a glauber - sudarshan representation as presented in @xcite .
the starting point of the discussion was the characteristic function @xmath7 of a spats , @xmath8 e^{-\bar n|\beta|^2}.\ ] ] by fourier transform the resulting @xmath0 function is derived as @xmath9e^{-|\alpha|^2/\bar n},\ ] ] which is a regular function .
experimental data were used for a mean photon number of @xmath10 and a quantum efficiency of @xmath11 .
the function @xmath7 was readily obtained from measured quadratures @xmath12 via @xmath13 it was directly sampled from @xmath14 data points .
we observe that the experimentally obtained curve tends to zero within a fraction of its standard deviation , @xmath15.\ ] ] however , the latter grows exponentially with @xmath16 . in order to calculate the glauber - sudarshan @xmath0 function via fourier transform ,
@xmath17 one has to regularize @xmath7 . in our previous work ,
we simply cutoff @xmath7 for @xmath18 .
this is equivalent to the multiplication of @xmath7 with a rectangular filter , @xmath19 , with @xmath20 for @xmath21 and @xmath22 elsewhere .
however , this method can only be applied in special cases .
first , the state must be described by a well - behaved @xmath0 function , and its characteristic function has to decay sufficiently fast in order to justify the cutoff regularization .
if this is not the case , one can not perform the fourier transform to obtain a @xmath0 function .
second , the systematic error has to be estimated by some assumptions on the behavior of the characteristic function for large @xmath23 .
we used the theoretical expectation of the characteristic function with properly chosen parameters . for a completely unknown state ,
such a procedure becomes meaningless . in the case of the spats
, we obtained the @xmath0 function for mean thermal photon numbers of @xmath24 , for details see @xcite . for
smaller mean thermal photon numbers the reconstruction of the @xmath0 function faces severe limitations .
the smaller @xmath25 , the broader the characteristic function becomes , and the larger is the statistical uncertainty at a reasonable cutoff parameter .
therefore , one can not find a useful trade - off between the systematic and the statistical error .
the former increase with lower @xmath26 , and the statistical uncertainty is growing with larger @xmath26 .
for an example we refer the reader to the end of the next section . under such circumstances ,
other nonclassicality criteria can be applied @xcite , which are sufficient but not necessary .
from a more general perspective to be used in the following , we may multiply the characteristic function by a filter function @xmath27 , @xmath28 for a general study of such a scenario cf .
the special case discussed so far is contained in this approach for a rectangular filter . to obtain a quasiprobability including the full information on the quantum state under study by fourier transform of @xmath29 , the filter must not have zeros anywhere in the complex plane . in view of the radial symmetry of our quantum states , the fourier transform of @xmath29
is given by @xmath30 this function , together with its variance , @xmath31 can be readily calculated from the set of data .
this expression for the variance of the quasiprobability is readily derived from the statistical sampling of the characteristic function according to eq .
( [ eq : cf - samp ] ) .
now we make use of the recently introduced concept of nonclassicality quasiprobabilities @xcite .
we introduce a so - called nonclassicality filter , @xmath32 , with the following properties : 1 .
@xmath33 decays faster than @xmath34 for any filter width @xmath35 in order to regularize the @xmath0 function and its statistical uncertainty for any quantum state .
the fourier transform of @xmath33 is non - negative , such that negativities in the nonclassicality quasiprobability are unambiguously caused by the negativity of the state s
@xmath0 function .
the parameter @xmath6 scales the filter @xmath33 such that for @xmath36 the filter approaches one .
practically , we implement this by @xmath37 .
the support of @xmath33 is the complex plane , such that eq .
( [ eq : filter : phi ] ) is invertible for every @xmath23 .
the first requirement ensures that the integrals in eq .
( [ eq : p - reg : hankel ] ) and eq .
( [ eq : var : p : hankel ] ) are finite , when the filter @xmath27 is identified with the nonclassicality filter @xmath33 .
the second condition makes sure that the negativity of @xmath38 unambiguously represents the nonclassicality of the state .
in contrast to this , a rectangular filter @xmath19 has a nonnegative fourier transform .
hence , for such a filter negativities of @xmath38 must not be interpreted as nonclassical effects without assumptions about the influence of the filter on the regularized @xmath0 function . in @xcite ,
this made the estimation of systematic errors necessary .
the third condition can be used for maximizing the significance of the observed nonclassical effects . on the one hand ,
a larger filter width @xmath6 may increase the negativities in the regularized @xmath0 function , one the other hand , this will definitely increase the variance .
we may tune @xmath6 in order to optimize the statistical significance @xmath39 of the negativities , defined via @xmath40 the fourth requirement is of fundamental importance : it ensures that the regularized function @xmath38 still contains the full information on the quantum state .
such @xmath41 functions , which fulfill all the four conditions , we refer to as nonclassicality quasiprobabilities .
a proper nonclassicality filter can be constructed by the autocorrelation of a function @xmath42 , @xmath43 with the normalization @xmath44 .
the width parameter is introduced by @xmath45 .
the positivity of its fourier transform is guaranteed by the properties of any autocorrelation function .
furthermore , if @xmath42 decays sufficiently fast , as required by condition ( 1 ) , @xmath33 does as well .
therefore , by choosing @xmath46 and calculating the autocorrelation , we obtain a suitable representative of a nonclassicality filter .
the single - photon - added thermal states are generated in a conditional way by exploiting the parametric amplification at the single - photon level in a nonlinear type - i @xmath23-barium borate ( bbo ) crystal pumped by the second harmonic of a mode - locked picosecond ti : sapphire laser ( see fig .
[ fig : setup ] ) . when no extra field is injected in the crystal
, a pump photon can be converted into two spontaneously and simultaneously generated photons ( named signal and idler ) correlated in frequency and in momentum .
the click of the on / off avalanche photodetector d , which is placed in the idler path after narrow spectral and spatial filters ( f ) , is used to conditionally prepare a single photon in a well - defined spatiotemporal mode of the signal channel @xcite . ) by a single photon . a click in the on - off detector d
prepares the photon - added thermal state @xmath47 and triggers its balanced homodyne detection ( bhd ) .
[ fig : setup ] ] on the other hand , if the parametric crystal is seeded with some light , described by the operator @xmath48 , stimulated emission comes into play , and single - photon excitation of such a state , always converting it into a nonclassical one , is conditionally obtained when one photon is detected in the idler mode @xcite .
field quadratures of the output signal state are then conditionally measured on a pulse - to - pulse basis using an ultrafast balanced homodyne detection scheme @xcite .
here we used a pseudo thermal source , obtained by inserting a rotating ground glass disk in a portion of the laser beam ( see @xcite ) , for injecting the parametric amplifier and producing spats . to illustrate the power of nonclassicality quasiprobabilities ,
let us consider a spats with @xmath49 and @xmath50 . in fig .
[ fig : phi:0.49 ] , we show the experimentally reconstructed characteristic function @xmath51 . obviously
, the fourier transform of this quantity does not exist as a regular function , since @xmath51 does not approach zero for large @xmath23 as its theoretical expectation @xmath52 does .
this is due to the fact that the uncertainty grows exponentially .
although both the experimental result and the theoretical expectation agree within two standard deviations , the former may even diverge within the divergent noise level .
in contrast to the results in @xcite , it is not obvious just from experimental data , that the characteristic function tends to zero for large @xmath23 .
moreover , it is not possible to find a reasonable compromise between a low systematic error ( requiring a large cutoff parameter @xmath26 ) , and a statistical uncertainty being sufficiently small to obtain significant negativities in the filtered @xmath0 function . and @xmath53 : the experimental result @xmath51 , the theoretical expectation @xmath52 , and the result @xmath54 of filtering for the filter width @xmath55 .
the shaded area corresponds to one standard deviation . ]
the application of the nonclassicality filter with a width @xmath56 leads to an integrable characteristic function @xmath54 .
we emphasize that the shown curve is obtained from the experimental data .
we also calculated its standard deviation , which is included in the line thickness .
therefore , this function is suited for deriving the corresponding nonclassicality quasiprobability by fourier transform .
figure [ fig : p:0.49 ] shows the result .
we observe a distinct negativity at the origin of phase space , with a significance of @xmath57 standard deviations . by the definition of nonclassicality quasiprobabilities ,
this negativity is solely due to the nonclassicality of the state . .
the blue shaded area corresponds to one standard deviation . ]
we may also reconsider the data of the spats with @xmath58 by our filtering procedure .
we obtain a nonclassicality quasiprobability @xmath59 which looks similar to the one in fig .
[ fig : p:0.49 ] . by optimizing the filter width to @xmath60
, we get a maximum significance of @xmath61 standard deviations , which exceeds that for the rectangular filter .
more importantly , the estimation of a systematic error which was previously needed for the assessment of nonclassicality and had been based on a - priori theoretical assumptions
now becomes superfluous . for comparison ,
let us try to regularize the state with @xmath49 and @xmath50 , whose characteristic function is shown in fig .
[ fig : phi:0.49 ] , with a rectangular filter . since this is not a nonclassicality filter of the type defined in sec .
iii a , we have to consider the systematic error , which comes from the cutoff . from fig .
[ fig : phi:0.49 ] , two possible cutoff parameter may be reasonable : on the one hand , we may choose @xmath62 , since from this point the deviations of the theoretical and experimental characteristic functions @xmath52 and @xmath51 grow strongly .
the corresponding regularized @xmath0 function with its standard deviation ( shaded blue area ) and systematic error ( dark red area ) is shown at the left side of fig .
[ fig : rectfilter : twosettings ] .
we clearly see that the statistical uncertainty is negligible , while the systematic error is partly even larger than of the @xmath0 function
. therefore , a - priori assumptions about the state , which are the basis for the estimation of the systematic error , are crucial .
moreover , the systematic error is larger than the size of the negativity .
functions regularized with a rectangular filter .
the cutoff parameter at the left side of the figure is rather small , leading to large systematic errors ( red shaded ) . for a larger cutoff parameter , the statistical uncertainty (
blue shaded ) becomes dominant , see the right side of the figure . ] on the other hand , we may set @xmath63 , where the experimental characteristic function @xmath51 is close to zero .
the resulting @xmath0 function is shown at the right side of fig .
[ fig : rectfilter : twosettings ] . in this case , the systematic error is small , while the statistical uncertainty is dominating .
the significance of the negativity of the filtered @xmath0 function is less than @xmath64 standard deviations .
therefore , we are not able to obtain statistically significant negativities by applying a rectangular filter , if we simultaneously try to achieve low systematic errors due to the regularization .
the reason is that the characteristic function of a state with such a small mean photon number approaches zero only for larger @xmath23 , where the standard deviation is already extremely large .
this problem can only be overcome by using suitable nonclassicality filter , which do not require the consideration of systematic errors in order to verify nonclassicality .
let us assume that the characteristic function @xmath7 describes a quantum state , but we measure this state with a non - unit quantum efficiency @xmath65 .
the characteristic function of the measured state is given by @xmath66 since the corresponding @xmath0 function is the fourier transform , this rescaling of @xmath23 leads to a rescaling of the argument of the @xmath0 function , @xmath67 therefore , a non - unit quantum efficiency does not degrade nonclassicality , and removal of losses from experimental data only rescales the @xmath0 function , but does not affect its course and uncertainty .
in contrast , this is not the case for the wigner function whose negativities more and more disappear with decreasing @xmath65-values .
how is the situation for nonclassicality quasiprobabilities ?
for answering this question , we note that the filtered characteristic function of a state , which suffered losses , reads as @xmath68 we observe that the characteristic function of the lossy state , @xmath69 , and the one of the ideal state , @xmath70 are not connected by simple rescaling
. however , they can be easily connected if one allows to rescale the filter width as well : @xmath71 hence , the characteristic function of a lossy state with some width @xmath6 , which is on the left side of the equation , is given by the characteristic function of the ideal state with filter width @xmath72 by additionally rescaling the argument @xmath73 . removing the losses by post - processing and
simultaneously adapting the width of the nonclassicality filter leads simply to scaled results with no better significance .
therefore , the removal of losses does not uncover nonclassical effects which do not already appear in the nonclassicality quasiprobabilities of the lossy state .
finally , we note that our method may visualize nonclassicality even for rather small quantum efficiencies .
simulations show that we find for the spats with @xmath74 , for our sample of @xmath14 data points , negativities in the nonclassicality quasiprobability with a significance of at least three standard deviations , if @xmath75 .
this @xmath65-value is only limited from below by the size of the sample .
in contrast , for @xmath76 the wigner function is always nonnegative
. therefore , the negativities of the nonclassicality quasiprobabilities are more sensitive to nonclassical effects than negativities of the wigner function .
we have applied the concept of nonclassicality quasiprobabilities to experimental data of single - photon added thermal states . even though the glauber - sudarshan @xmath0 function of these states is regular in general , its approximate reconstruction is feasible only for a certain parameter range . moreover
, it requires to make use of some precognition on the state under study .
our quasiprobability approach does not require such a precognition , it works for any quantum state even when the @xmath0 function is strongly singular and it also suppresses the experimental sampling noise .
we have shown that the nonclassicality filters needed in our procedure , suppress the exponential growth of experimentally determined characteristic functions , which yields integrable functions .
hence , fourier transform delivers nonclassicality quasiprobabilities with finite statistical uncertainties . by optimization of the filter width , significant negativities in the quasiprobabilities
are found for nonclassical states .
for our chosen example , an approximate reconstruction of the @xmath0 function was shown to be no longer useful . with the accessible set of @xmath14 data points we could demonstrate negativities in the experimentally determined nonclassicality quasiprobability with a significance of about @xmath57 standard deviations .
this result is solely limited by the statistical uncertainties caused by the finite size of the available set of experimental data , it could be further improved by extending this set .
we have also considered the role of imperfect detection .
in fact , the detection efficiency can be completely eliminated by a proper rescaling of arguments in our functions .
thus , even with a rather small efficiency one can identify all nonclassical effects , provided the sampling noise is sufficiently small .
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. phys . * 42 * , 114005 ( 2009 ) . | we report the experimental reconstruction of a nonclassicality quasiprobability for a single - photon added thermal state .
this quantity has significant negativities , which is necessary and sufficient for the nonclassicality of the quantum state .
our method exhibits several advantages compared to the reconstruction of the @xmath0 function , since the nonclassicality filters used in this case can regularize the quasiprobabilities as well as their statistical uncertainties .
a priori assumptions about the quantum state are therefore not necessary .
we also demonstrate that , in principle , our method is not limited by small quantum efficiencies . |
coset spaces are widely used in a variety of contexts , for example as target spaces within string theory or more generally within non - linear sigma models . for supersymmetric theories of this kind ,
a thorough understanding of the geometry of super coset spaces is therefore essential . on the other hand , supersymmetric theories with coset spaces as the base
naturally have a superspace formulation in terms of super coset spaces , the most prominent examples being supersymmetric theories in flat space .
these can be formulated in terms of flat superspace , which is the quotient of the super poincar group by its lorentz subgroup .
we aim to provide in this paper a firm mathematical basis for the geometry of super coset spaces , collating and making rigorous results often only sketched in the literature and extending results only discussed for ordinary coset spaces to the supersymmetric case .
the geometry of a ( super ) coset space @xmath0 , i.e. its frame and connection , can be determined in terms of the geometry of @xmath1 .
in fact , it is well known that by pulling back the maurer - cartan one - form on the group @xmath1 to the base @xmath0 one can obtain the frame and connection on the base , see e.g. @xcite . while this is often stated in the literature a geometric explanation of this
is usually omitted . treating the super lie group @xmath1 as a principal bundle over @xmath0
we give a self - contained account of the geometry of coset spaces focussing in particular on the relation between the geometry in the bundle and the geometry in the base .
coset spaces are characterized by high symmetry ; most of their isometries can be derived from the left action of @xmath1 on the coset space and as such the isometry group of @xmath0 contains @xmath1 . on the other hand ,
the isometries of the coset space can be determined directly from its geometry : in the case of ordinary space the infinitesimal isometries , i.e. the killing vector fields , are defined as the directions along which the metric tensor is dragged into itself . in the case of superspace where the tangent space group of the supermanifold under consideration must correspond to the even grassmann extension of the tangent space group of the body of the supermanifold , i.e. to @xmath2 such a definition is no longer feasible .
this is as , in this case , there exists no physically natural superspace generalization of the concept of metric @xcite : if one were to introduce a supermetric the tangent space group of the supermanifold derived from this would be too large , and hence would not correspond to the even grassmann extension of @xmath2 , thus rendering the theory unphysical . while this problem is often noted in the literature its relevance to the definition of killing supervectors is seldom elucidated .
one aim of this paper is therefore to make rigorous and clarify the notion of killing supervector fields in the context of superspace . as we shall see it is possible to define killing supervector fields as those infinitesimal transformations that leave the frame and connection invariant up to a gauge transformation , see
also @xcite .
this condition can be rephrased in terms of the commutator of some generalized lie derivative and the covariant derivative , cf .
@xcite . in the case of super coset spaces
we shall see that this definition reproduces the killing supervectors derived from the left action of the group on the super coset space which justifies this definition also for more general spaces .
derivations such as the covariant derivative and generalized lie derivative are an integral part of the geometry of coset spaces .
we give a geometric interpretation to derivations such as these on @xmath0 by defining them in terms of maps on the bundle @xmath1 and associated bundles .
the organization of this paper is as follows : first we briefly review the construction of @xmath1 as a principal bundle over the coset space @xmath0 .
we then discuss the geometry of @xmath1 focussing in particular on its invariant vector fields and the maurer - cartan form in the bundle . in sections
[ sec : connection][sec : curvature ] we discuss in detail how the geometry in the base , i.e. connection and frame , torsion and curvature , can be obtained from the geometry in the bundle . in section [ sec : bundle ] we introduce associated bundles and briefly review some aspects of supertensor bundles that will be important when discussing derivations on associated bundles .
we then introduce those ( local ) bundle maps that will allow us to define in section [ sec : derivations ] derivations on supertensor bundles , such as the covariant derivative , the lie derivative and the so - called @xmath3-covariant lie derivative . as we shall see in section [ sec : killing ] , killing supervectors , i.e. the supervectors associated to infinitesimal isometries , can be defined in terms of a so - called generalized lie derivative which combines an arbitrary transformation in the base with an arbitrary gauge transformation in the bundle , and which we require to commute with the covariant derivative .
finally , in section [ sec : example ] , we shall apply the concepts and methods introduced in the previous sections to flat superspace as an example .
consider a super lie group @xmath1 with super lie subgroup @xmath3 .
a super lie group shall be defined in the sense of dewitt , see @xcite , as a group which is also a supermanifold and which has a differentiable group multiplication .
we define the super coset space @xmath0 via the equivalence of group elements in @xmath1 under right multiplication by an element of @xmath3 , @xmath4 the coset space @xmath0 naturally inherits a supermanifold structure from the supermanifold @xmath1 @xcite .
the geometry of the coset space @xmath0 is also inherited from @xmath1 . to study this we consider @xmath1 as a principal bundle over @xmath0 with fibre @xmath3 .
the construction in the non - supersymmetric case @xcite is directly transferred to the supersymmetric case .
first we have the bundle projection map @xmath5 the inverse image @xmath6 of a point @xmath7 in the base gives us the fibre above that point which is clearly isomorphic to @xmath3 . to define the local trivializations of the bundle we consider charts @xmath8 on the base .
within a particular chart it is always possible to choose a local section . by a local section we mean a map @xmath9 which satisfies @xmath10 .
the local section @xmath11 provides us with a coset representative @xmath12 for any @xmath13 . using this local section we define the canonical local trivialization for the bundle @xmath14 note that the inverse is easily constructed as @xmath15 .
the transition functions for @xmath16 are defined as @xmath17 where @xmath18 .
the map @xmath19 is clearly just left multiplication by an element of @xmath3 , and we shall use the notation @xmath20 .
the trivializations are then related as @xmath21 the structure group is therefore @xmath3 and acts on the fibre @xmath3 by left multiplication .
we thus have that @xmath1 is a principal bundle over @xmath0 with structure group @xmath3 .
we denote this as @xmath22 .
let us denote the super lie algebra associated to the super lie group @xmath1 by @xmath23 .
the generators of @xmath23 will be denoted by @xmath24 , @xmath25 ; they have definite parity , either even or odd and we will set @xmath26 for @xmath24 even and @xmath27 for @xmath24 odd .
the index in the exponent of @xmath28 is as such to be understood as taking the values @xmath29 or @xmath30 according to whether it is even or odd .
a general element of the super lie algebra is then expanded in the generators as @xmath31 , where the @xmath32 are pure supernumbers chosen such that @xmath33 is even .
as such the super lie algebra consists of even elements only , in fact @xmath23 can be viewed as the even part of a larger berezin superalgebra @xcite .
the super lie group @xmath1 can then be obtained from its super lie algebra via the exponential mapping . for each element of the algebra @xmath34 we can construct two different supervector fields , @xmath35 and @xmath36 , defined by their action on a function @xmath37 on @xmath1 as @xmath38&{\stackrel{\mathrm{def}}{=}}{\frac{\mathrm{d}}{\mathrm{d}t}}\left(f\left(ge^{ta}\right)\right)\big|_{t=0}\\ \label{eqn : flat}a^\flat\big|_g[f]&{\stackrel{\mathrm{def}}{=}}{\frac{\mathrm{d}}{\mathrm{d}t}}\left(f\left(e^{ta}g\right)\right)\big|_{t=0}.\end{aligned}\ ] ]
we have thus obtained two maps from the algebra @xmath23 to the space of vector fields on @xmath1 given by @xmath39 and @xmath40 .
clearly these maps are linear .
the definition of the vector fields given above may be modified in the case that @xmath41 is an odd element of the berezin superalgebra simply by choosing the parameter @xmath42 to be an odd supernumber .
this ensures that @xmath43 is still a group element .
this way it possible to define the supervectors @xmath44 and @xmath45 for all @xmath7 .
it is easy to see that @xmath35 is a left - invariant vector field , whereas @xmath36 is right - invariant : @xmath46 here @xmath47 and @xmath48 are the group operations of left and right multiplication by @xmath49 , the lowered asterisk ( @xmath50 ) is used to denote the corresponding induced map on vector fields ( the pushforward ) .
the vector fields also satisfy @xmath51 here @xmath52 is the adjoint action of the group on its algebra which is induced from the adjoint action of the group on itself . for the latter we also use the notation @xmath52 .
we have @xmath53 and thus , in a matrix representation , the adjoint action on the algebra is thus just @xmath54 . under the lie bracket of supervector fields we find
@xmath55&=[a , b]^\sharp\\ \label{eqn : flatalgebra } [ a^\flat , b^\flat]&=-[a , b]^\flat\\ [ a^\sharp , b^\flat]&=0.\end{aligned}\ ] ] the bracket occurring on the right is the super lie algebra bracket .
the maurer - cartan one - form @xmath56 is a super lie algebra valued one - form defined on the super lie group as @xmath57 note that one should be careful when dealing with forms acting on vectors in the case of supersymmetry , our conventions are given in appendix [ sec : formconventions ] .
the maurer - cartan one - form is clearly left - invariant , whereas under right translations it transforms as @xmath58 the maurer - cartan form can be shown to satisfy @xmath59 which is the so - called _ maurer - cartan structure equation_. when working in a matrix representation of the group the maurer - cartan form may be represented as @xmath60 @xcite . throughout the remainder of this paper
we will occasionally work in a matrix representation where it is more convenient .
in this section we will construct a connection on the coset space @xmath0 .
we will see that this connection is naturally induced from the group @xmath1 , in particular from the maurer - cartan form .
a connection on a fibre bundle is defined quite abstractly in terms of a decomposition of the tangent space into so - called vertical and horizontal subspaces . while this definition may not be the definition of connection familiar from physics it will provide us with a deeper insight into the geometry . in section [ sec : localcon ] we will review how this abstract definition relates to the familiar notion of connection in physics .
geometrically a connection on the bundle @xmath1 can be thought of as a decomposition of the tangent space to the super lie group , @xmath61 , into vertical and horizontal subspaces , respectively .
this decomposition must be supersmooth and the horizontal subspaces must satisfy @xmath62 such a decomposition of the tangent space can be achieved by utilizing the left - invariant vector fields and the natural decomposition of the algebra arising from the subgroup @xmath3 .
let us denote the super lie algebra of the subgroup @xmath3 by @xmath63 .
we then choose a subspace @xmath64 in @xmath23 complementary to @xmath63 , i.e. @xmath65 the generators of the full algebra @xmath24 , @xmath66 , can then be split up into the generators of @xmath63 , @xmath67 , @xmath68 , and the remaining generators @xmath69 , @xmath70 .
the structure constants @xmath71 of @xmath23 are then defined by @xmath72 & = f_{ij}{}^k h_k \\
\left[h_i , k_a\right ] & = f_{ia}{}^j h_j + f_{ia}{}^b k_b \\ \label{eqn : algebra3 } \left[k_a , k_b\right ] & = f_{ab}{}^j h_j + f_{ab}{}^c k_c.\end{aligned}\ ] ] the bracket here is the graded lie bracket which satisfies the symmetry @xmath73=-(-1)^{pq}[t_q , t_p]$ ] .
if @xmath64 can be chosen such that the structure constants @xmath74 vanish , i.e. @xmath75\subseteq\mathfrak{k}$ ] , then the group @xmath1 is said to be _
reductive_. as we shall see this is an important property and we shall assume that @xmath1 is reductive throughout the remainder of this paper . the decomposition of the algebra in eq .
( [ eqn : algebrasplit ] ) naturally gives a decomposition of the tangent space to the group into horizontal and vertical subspaces .
we may use the generators of the algebra to define a basis of the vertical and horizontal subspaces .
we take @xmath76 to be a basis of @xmath77 and @xmath78 to be a basis of @xmath79 , i.e. @xmath80 where here @xmath81 denotes the real supernumbers .
this decomposition is clearly smooth and of the form @xmath82 . from eq .
( [ eqn : rightactiononsharp ] ) and the reductive property f the group it is easily seen that eq .
( [ eqn : horizontalrighttranslation ] ) is satisfied . given a notion of horizontal and vertical vectors , it is natural to define horizontal and vertical differential forms .
a differential form on the bundle is called vertical ( respectively horizontal ) if it vanishes whenever one of the vectors on which it is evaluated is horizontal ( respectively vertical ) .
for example , expanding the maurer - cartan form , eq .
( [ eqn : maurercartan ] ) , in the algebra generators we have @xmath83 it is then easy to see that @xmath84 hence @xmath85 will vanish when acting on any vertical vector whereas @xmath86 vanishes on any horizontal vector .
@xmath85 is therefore a horizontal form and @xmath87 a vertical form .
( [ eqn : maurercartandecomp ] ) can thus be thought of as a decomposition of the maurer - cartan form into its horizontal and vertical parts .
it is usually more convenient to define a connection in terms of a _ connection one - form_. this is a super lie algebra valued one - form , @xmath88 , on the bundle and it is required to satisfy @xmath89 the horizontal subspace is then defined as the kernel of @xmath88 , i.e. @xmath90 we will now show that the vertical part of the maurer - cartan form , @xmath91 , can be taken to be the connection one - form consistent with the definition of horizontal and vertical subspaces defined in eqs .
( [ eqn : connection1],[eqn : connection2 ] ) .
firstly , as @xmath92 is horizontal , it follows immediately from eq .
( [ eqn : maurercartan ] ) that @xmath93 we also find immediately from eq .
( [ eqn : rightactionmaurercartan ] ) that @xmath94 these two equations can then be compared directly with eqs .
( [ eqn : connection1],[eqn : connection2 ] ) . also , as the form @xmath91 is vertical , its kernel is precisely the horizontal subspace .
thus we may choose the connection one - form as @xmath95 .
the definition of a connection in terms of horizontal and vertical subspaces may seem a little abstract , and the connection one - form @xmath88 is not the connection usually dealt with in physics . in this section
we shall review the relation of this abstract definition of connection to the more familiar notion of connection in physics . to do this
we shall consider parallel transport . given a curve @xmath96\to g / h$ ] in the base we define a _ horizontal lift _ of @xmath97 to be a curve @xmath98\to g$ ] in the bundle which satisfies @xmath99 and for which the tangent vector to @xmath100 lies in @xmath101 .
for each point @xmath102 there is a unique horizontal lift of @xmath97 for which @xmath103 .
further , for @xmath104 , the horizontal lift passing through @xmath105 is simply @xmath106 .
consider a point @xmath107 above @xmath108 , and construct the horizontal lift @xmath100 of @xmath97 satisfying @xmath109 .
then the value @xmath110 is said to be the _ parallel transport _ of @xmath111 along @xmath97 .
let us now analyze this construction as viewed from a local trivialization . let us choose the local section s where we only need to consider one chart .
] such that @xmath112 , we may then decompose the horizontal lift of @xmath97 as @xmath113 where @xmath114 . then , if we let @xmath33 be the tangent vector to @xmath97 and let @xmath115 be the tangent vector to @xmath100 , it is possible to show ( see appendix [ sec : appendix1 ] ) that @xmath116 note that this result is here written in a matrix representation .
also , @xmath117 is the exterior derivative on the base @xmath0 and should not be confused with the exterior derivative on the group @xmath1 which we used in section [ sec : maurercartan ] .
now , since @xmath115 is horizontal we have that @xmath118 , hence using eqs .
( [ eqn : connection1],[eqn : connection2 ] ) we find @xmath119 with this equation in mind we introduce the _ local connection _ , @xmath120 , a super lie algebra valued one - form in @xmath121 , defined as @xmath122 thus we see from eq .
( [ eqn : localconnectionmotivation ] ) that @xmath123 from this equation , or its formal solution in terms of the path ordered exponential , we see that the local connection is precisely the connection familiar to us from physics .
this will become even more apparent in section [ sec : covder ] when we work with associated bundles .
note that @xmath120 clearly depends on the choice of local section .
the choice of local section can be seen to be precisely what we would naturally call the choice of gauge .
this view of gauge choice is one of the many nice aspects of working in the language of bundles . to see this in a little more detail
let us consider the connection for two different choices of local section : @xmath124 and @xmath125 .
the two local sections can clearly be related by a right multiplication , @xmath126 , with @xmath127 dependent on @xmath128 .
it is possible to show ( see appendix [ sec : appendix1 ] ) that for a vector @xmath129 we have @xmath130 from this it follows directly that @xmath131 since @xmath33 is arbitrary we deduce @xmath132 which is the usual transformation rule for a connection under the gauge transformation given by the local field @xmath127 .
in the previous section we have discussed how the connection one - form on the bundle @xmath1 can be taken to be the vertical part of the maurer - cartan one - form .
when pulled back under a local section this gives us the usual connection on the base .
it is then natural to ask what the horizontal part of the maurer - cartan form is associated with .
we will show in this section that it is naturally associated with a frame .
consider the pullback of the horizontal components of the maurer - cartan form .
we define @xmath133 note that a coframe in @xmath121 is defined as a set of @xmath134 one - forms that are linearly independent at each @xmath135 . since @xmath136 there is clearly the right number of @xmath137 ; all that remains is to show pointwise linear independence .
consider a point @xmath135 .
suppose we introduce a set of supernumbers @xmath138 and impose that @xmath139 .
acting on an arbitrary vector @xmath140 and using the definition of pullback this gives @xmath141 now , since @xmath142 is horizontal it vanishes when acting on any vertical vector @xmath143 and hence we have @xmath144 the vector @xmath145 can be seen to be a completely arbitrary supervector in @xmath146 , this follows from the fact that an arbitrary curve @xmath147 can be decomposed in terms of the local trivialization as @xmath148 where @xmath149 is a curve in @xmath121 , and @xmath150 .
so let us expand @xmath145 in the basis of the @xmath151 as @xmath152 , where @xmath153 are therefore arbitrary supernumbers of parity @xmath41 since @xmath145 is even .
we then have @xmath154 choosing @xmath153 appropriately we see that @xmath155 for all @xmath41 , hence the @xmath137 are linearly independent .
the dual frame of vectors , @xmath156 , satisfying @xmath157 , is given by @xmath158 this is easily checked as @xmath159 here we have noted that the horizontal part of the supervector @xmath160 is just @xmath161 , its vertical part we have called @xmath162 which vanishes when acted on by @xmath163 .
the final line then follows immediately from eq .
( [ eqn : zetaketc ] ) .
let us consider the behavior of the frame under a gauge transformation , which , as remarked in section [ sec : localcon ] , is merely a change of local section .
we again introduce two local sections @xmath124 and @xmath126 and will consider how the frame @xmath164 is related to the frame @xmath156 .
first consider , for @xmath165 and @xmath37 some arbitrary function on @xmath1 , @xmath166 & = a^\sharp\big|_{l(p)h(p)}[f \circ \pi ] \nonumber\\ & = { \frac{\mathrm{d}}{\mathrm{d}t } } \left(f \circ \pi \left(l(p)h(p)e^{t a}\right ) \right)\big|_{t = 0}\nonumber\\ & = { \frac{\mathrm{d}}{\mathrm{d}t } } \left(f \circ \pi \left(l(p ) e^{t \mathrm{ad}_{h(p ) } a}h(p)\right ) \right)\big|_{t= 0}\nonumber\\ & = \left ( \mathrm{ad}_{h(p ) } a\right)^\sharp\big|_{l(p ) } [ f \circ \pi ] \nonumber \\ \label{eqn : adhpi } & = \pi _ * \big((\mathrm{ad}_{h(p ) } a)^\sharp\big|_{l(p ) } \big)[f].\end{aligned}\ ] ] now expand @xmath41 in the basis of @xmath64 as @xmath167 , where the @xmath168 are constant supernumbers of parity @xmath41 .
then , as the function @xmath37 is arbitrary , and by appropriate choice of the @xmath168 , we find @xmath169 let us introduce the coadjoint representation , @xmath170 , of the group @xmath1 defined by @xmath171 we will now again see the importance of the assumption that the group @xmath1 is reductive . in this case
we have @xmath75\subseteq\mathfrak{k}$ ] and thus the coadjoint representation furnishes us with a representation , @xmath172 , of the subgroup @xmath3 on the space @xmath64 @xmath173 thus , from eq .
( [ eqn : splodge ] ) , we finally have @xmath174 it follows immediately from eq .
( [ eqn : gaugetransformframe ] ) that the coframe transforms under a gauge transformation as @xmath175 this can also be derived directly from the definition eq .
( [ eqn : coframe ] ) using eq .
( [ eqn : xchangesection ] ) in a similar manner to that used in the case of the connection . we are primarily , though not solely , interested in the case when @xmath0 is a superspace , see section [ sec : intro ] .
recall that one crucial property of superspace is that its tangent space group must coincide with the even grassmann shell @xcite of the tangent space group of the body of the superspace under consideration
. this will be the case when @xmath3 is the even grassmann shell of @xmath2 .
further to this we require for a superspace that the representation @xmath176 is completely reducible , acting as @xmath2 rotations on the even coordinates and as @xmath177 rotations on the odd coordinates . in this case we will sometimes refer to the frame as being orthonormal although this is only true for the even part of the frame .
in the previous sections we have prescribed a supergeometry on the coset space @xmath0 by determining a local frame and connection .
( [ eqn : localconnectiondefinition],[eqn : coframe ] ) may be combined into one equation @xmath178 where we have expanded the connection in the generators of the algebra @xmath63 .
this equation is often stated in the literature @xcite in a matrix representation so that @xmath179 , see section [ sec : maurercartan ] . given a supergeometry it is natural to next calculate the torsion and curvature .
we will see that the torsion and curvature can be straightforwardly determined from the maurer - cartan structure equation , eq .
( [ eqn : maurercartanstructure ] ) .
first we define the torsion and curvature on the base . in this section
we will not explicitly display the dependence of the frame and connection on the local section @xmath180 , all quantities derived from them do , however , obviously retain this gauge dependence . from the local connection @xmath181 we define the curvature on the base as @xmath182 which can be expanded in components as @xmath183 .
this gives @xmath184 the torsion is naturally defined in terms of the exterior covariant derivative of the frame @xmath185 here @xmath186 is the connection @xmath181 written in terms of the coadjoint representation . using the definition of the coadjoint representation , eq .
( [ eqn : coadjoint ] ) , we see that to first order @xmath187 hence @xmath188 we may also consider the component form of the definitions of curvature and torsion .
we expand @xmath189 , and similarly @xmath190 , and also introduce the _ anholonomy supercoefficients _
, @xmath191 , via @xmath192=\mathcal{c}_{ab}{}^ce_c.\ ] ] it is then possible to show that @xmath193 - ( -1)^{ab } e_b [ \omega_a ] - \mathcal{c}_{ab}{}^c\omega_c + [ \omega_a,\omega_b].\end{gathered}\ ] ] using the conventions of appendix [ sec : formconventions ]
we can also show that @xmath194 - ( -1)^{xy}y[\omega(x ) ] - \omega([x , y ] ) + [ \omega(x),\omega(y)]\big)\ ] ] for supervectors @xmath33 and @xmath195 . these expressions will be useful later . with these definitions in mind
let us consider the pullback of the maurer - cartan structure equation , eq .
( [ eqn : maurercartanstructure ] ) , under the local section .
we have @xmath196 substituting in eq .
( [ eqn : theequation ] ) and separating out the @xmath64 and @xmath63 parts we find @xmath197 comparing these two equations with the definitions of the curvature and torsion two - forms we see that @xmath198 comparing to the component expansion of a @xmath7-form as given in eq .
( [ eqn : formexpansion ] ) we see that @xmath199 whilst it is sufficient for most applications to consider the torsion and curvature as defined in the previous section , it is nice to see how they are obtained in terms of the geometry of the bundle .
the first concept we need to define is the exterior covariant derivative , @xmath200 , on the bundle , not to be confused with that defined on the base used in the previous section .
it is defined by its action on an @xmath201-form @xmath202 on the bundle as @xmath203 here the supervector @xmath204 is the horizontal part of the supervector @xmath33
. now recall that the vertical part of the maurer - cartan form gave us the connection on the bundle @xmath205 . denoting the horizontal part by @xmath206
, we have @xmath207 the form @xmath208 is essentially the _ solder form _ on the bundle @xcite which can be seen as follows .
the solder form is a form defined on a frame bundle ; we will see in section [ sec : equiv ] how the principal bundle may be thought of as the frame bundle .
in particular , a frame @xmath209 corresponds to the point @xmath124 in the principal bundle . given a vector @xmath210 tangent to the bundle at this point the components of the solder form , @xmath211 ,
are defined to satisfy @xmath212 by expanding @xmath213 in the basis of the @xmath214 it is straightforward to check that @xmath215 solves this equation .
@xmath216 can therefore be considered as the collection of the components of the solder form into a single algebra valued form , thus in the following we will simply refer to @xmath208 as the solder form .
we may then define the quantities @xmath217 and @xmath218 which we call the torsion and curvature on the bundle .
these are defined in terms of the exterior covariant derivatives of the solder form and connection form , respectively , and are calculated to be @xmath219 note that @xmath217 is a @xmath64-valued two - form , whereas @xmath218 is @xmath63-valued .
a straightforward calculation shows that when pulled back under a local section these quantities give the definitions of the local torsion and curvature two - forms in eqs .
( [ eqn : curvaturedef],[eqn : torsiondef ] ) @xmath220 let us now consider how the torsion and curvature on the bundle may be expressed in terms of the structure constants of the algebra
. using eq .
( [ eqn : zetasplit2 ] ) and eqs .
( [ eqn : bundletorsion],[eqn : bundlecurvature ] ) we see that @xmath221 where in the last line we have used the maurer - cartan structure equation eq .
( [ eqn : maurercartanstructure ] ) .
as @xmath216 we find @xmath222 \\ & = \frac{1}{2}\zeta^a \wedge \zeta^b f_{ba}{}^c k_c + \frac{1}{2}\zeta^a \wedge \zeta^b f_{ba}{}^i h_i.\end{aligned}\ ] ] if we then split this up into its @xmath64 and @xmath63 parts we find @xmath223 if we pullback these equations to the base as in eq .
( [ eqn : pullbackct ] ) we obtain the expressions for the local torsion and curvature we derived earlier in eqs .
( [ eqn : torsioncomponent],[eqn : curvaturecomponent ] ) .
given a principal bundle @xmath224 we construct an associated fibre bundle as follows . consider a manifold @xmath225 on which the structure group @xmath3 acts on the left .
then we define an equivalence relation on @xmath226 by @xmath227 where @xmath228 . in the following
we shall denote the equivalence class of the point @xmath229 as @xmath230 $ ] . from this equivalence relation
we define the associated fibre bundle as the coset space @xmath231 , see @xcite . in the following we shall consider associated bundles only where the fibre @xmath225 is a supervector space is a supervector space can be linearly combined to give new local sections in a way that will become apparent in section [ sec : supertensorbundles ] . ] . in these cases @xmath3 acts on the fibre via some representation @xmath232 and the equivalence relation , eq .
( [ eqn : equivrel ] ) , reads @xmath233 defining the local bundle map @xmath234 we can define the action of @xmath3 on a local section of a general associated bundle @xmath235 $ ] as @xmath236 \hspace{5pt } \mapsto \hspace{5pt } [ ( r_h^{(l)}\big(l(p)\big ) , \xi(p))]\ ] ] which , using the equivalence relation , can be rewritten as @xmath237.\ ] ] note that @xmath238 is a group homomorphism , i.e. we have @xmath239 based on the definition of @xmath240 we can define the action of @xmath63 on a local section @xmath235 $ ] of a general associated bundle . for @xmath241 we define @xmath242 we hence have @xmath243 in this section we shall show that the orthonormal . ]
frame bundle @xmath244 is equivalent to the principal bundle .
note that the fibre of the frame bundle above the point @xmath7 is given by @xmath245 .
we define the local trivialization of the frame bundle as @xmath246 where we have defined the frame bundle projection map @xmath247 as @xmath248 the transition functions @xmath249 of the frame bundle are then given by @xmath250 where @xmath251 .
we thus already see that the structure group of the orthonormal frame bundle is equal to the structure group of the principal bundle , see section [ sec : principal ] . in order to fully establish the equivalence between the principal bundle and the frame bundle we shall now show that the transition functions of the principal bundle are equal to those of the frame bundle . in order to do this
consider the action of @xmath252 on @xmath253 @xmath254 now we have using the definition of the transition functions of the principal bundle @xmath255 , see eq .
( [ eqn : localtriv ] ) , @xmath256 and hence we find @xmath257 we thus have @xmath258 this proves that the transition functions of the frame bundle equal those of the principal bundle .
we thus see that the principal bundle and the frame bundle are equivalent bundles . in the following
we shall , for convenience , use the principal bundle rather than the frame bundle in order to formulate associated bundles . in this section we shall briefly discuss the equivalence relations eq .
( [ eqn : equivrel ] ) in the case of general tensor bundles .
although it is more natural to consider tensor bundles associated to the frame bundle we will in this section use the equivalent principal bundle for the ease of notation .
let us consider a pure , i.e. even or odd , section @xmath259 of a general tensor bundle with both contravariant and covariant indices .
we write @xmath260.\ ] ] here we define the equivalence by @xmath261 where we set @xmath262 here @xmath263 is the parity function as defined in eq .
( [ eqn : parityfunction ] ) , @xmath201 denotes the total number of indices and we have set @xmath264 .
we define the local section of a general supertensor bundle to satisfy the following linearity property under left multiplication by an arbitrary pure supernumber @xmath265 @xmath266,\ ] ] where @xmath267 is the sum over the parities of the lower indices . from eq .
( [ eqn : linearity ] ) and from the fact that @xmath268 we can infer the linearity property under right multiplication @xmath269.\ ] ] from these last two equations we see that contravariant tensor bundles are left - linear , i.e. they satisfy @xmath270,\ ] ] whereas covariant tensor bundles are right - linear , i.e. @xmath271.\ ] ] defining the basis of a general supertensor bundle by s that occurs in the definition of the basis is to be understood as an ordered collection , i.e. the @xmath272 s ought not be swapped . ] @xmath273\end{gathered}\ ] ] we can rewrite the local section @xmath259 of eq .
( [ eqn : supertensor ] ) in terms of this basis as @xmath274 \nonumber\\ & = ( -1)^{\delta_n(a , a ) + \delta_n(\tilde{a},\tilde{a})}(-1)^{(s + \sum a + \sum \tilde{a})(\sum \tilde{a } ) } s^{a_1 \cdots a_i}{}_{\tilde{a}_{i + 1 } \cdots \tilde{a}_{i + j}}{}^{a_{i + j + 1 } \cdots } \cdots \nonumber \\ & \hspace{15pt } e_{a_1}^{(l ) } \otimes \cdots \otimes e_{a_i}^{(l ) } \otimes e^{\tilde{a}_{i + 1}}_{(l ) } \otimes \cdots \otimes e^{\tilde{a}_{i + j}}_{(l ) } \otimes e_{a_{i+ j + 1}}^{(l ) } \otimes \cdots \nonumber \\ & = ( -1)^{\delta_n(a + \tilde{a},a + \tilde{a})}(-1)^{(s + \sum \tilde{a})(\sum \tilde{a } ) } s^{a_1 \cdots a_i}{}_{\tilde{a}_{i + 1 } \cdots \tilde{a}_{i + j}}{}^{a_{i + j + 1 } \cdots } \cdots \nonumber\\ & \hspace{15pt } e_{a_1}^{(l ) } \otimes \cdots \otimes e_{a_i}^{(l ) } \otimes e^{\tilde{a}_{i + 1}}_{(l ) } \otimes \cdots \otimes e^{\tilde{a}_{i + j}}_{(l ) } \otimes e_{a_{i+ j + 1}}^{(l ) } \otimes \cdots , \nonumber\end{aligned}\ ] ] where we have used the linearity property eq .
( [ eqn : linearity ] ) .
note that in the case of contravariant tensor bundles this formula simplifies to @xmath275 and in the case of covariant tensor bundles we have @xmath276 using the definition of the action of @xmath3 on a local section @xmath259 as given in eq .
( [ eqn : hactionsection ] ) we find after a slightly lengthy calculation for the transformation of the basis under @xmath3 @xmath277 as expected . from the definition of the basis eq .
( [ eqn : basisdef ] ) and the linearity property eq .
( [ eqn : linearity ] ) one can easily deduce the following properties of the tensor product @xmath278 where @xmath279 , @xmath280 and @xmath281 are local sections of general tensor bundles and @xmath265 is a supernumber .
let us define the following ( local ) bundle maps @xmath282 while @xmath47 , see section [ sec : invvecfields ] , is a global bundle map from @xmath283 here written locally in the patch @xmath284 the map @xmath285 depends on the local section @xmath124 and , for it to be well - defined , both its domain and range must be restricted to @xmath284 . in the following we shall however ,
for convenience , also restrict both the domain and range of the map @xmath47 to @xmath284 .
then the _ left _
@xmath3-compensator @xmath286 is defined by the equation , see @xcite , @xmath287 i.e. , we have @xmath288 and @xmath289 and hence we see that the map @xmath285 preserves the local section @xmath124 , while this is not true for the map @xmath47 . for the map @xmath290 which also depends on the local section @xmath124 only the domain need be restricted to @xmath284 ; in the following , however , we shall for convenience also require its range to be restricted to @xmath284 .
we can then , in accordance with eq .
( [ eqn : lefthcomp ] ) , also define the _ right _ @xmath3-compensator @xmath291 by
@xmath292 i.e. , @xmath293 note that the map @xmath294 introduced in section [ sec : associated ] , see eq .
( [ eqn : defrhl ] ) , is just a specific case of the map @xmath290 introduced here .
the maps @xmath285 and @xmath290 induce maps on the base that we shall denote by @xmath295 and @xmath296 , respectively .
we have @xmath297 where one should note that the map @xmath298 on the base depends on the local section @xmath124 .
we can then rewrite eqs .
( [ eqn : lgl],[eqn : lg ] ) and eq .
( [ eqn : rgl ] ) , respectively , as @xmath299 using eqs .
( [ eqn : pil],[eqn : pir ] ) we can derive relations for the vectors @xmath300 and @xmath301 similar to those in eqs .
( [ eqn : sharp],[eqn : flat ] ) .
we have @xmath302 & = a^\sharp \big|_{l(p ) } [ f \circ \pi ] \nonumber \\ & = { \frac{\mathrm{d}}{\mathrm{d}t}}\left(f \circ \pi\left(l(p ) e^{ta}\right ) \right)\big|_{t=0}\nonumber \\ & = { \frac{\mathrm{d}}{\mathrm{d}t } } \left ( f \circ \pi \circ r_{e^{ta}}^{(l)}l(p ) \right ) \big|_{t=0 } \nonumber \\ & = { \frac{\mathrm{d}}{\mathrm{d}t } } \left ( f \circ r_{e^{ta}}^{(l ) } \circ \pi \circ l(p ) \right ) \big|_{t=0 } \nonumber \\ \label{eqn : expansionf(r ) } & = { \frac{\mathrm{d}}{\mathrm{d}t } } f(r_{e^{ta}}^{(l)}(p))\big|_{t=0}\end{aligned}\ ] ] and similarly we find @xmath303 = { \frac{\mathrm{d}}{\mathrm{d}t } } f(l_{e^{ta}}(p))\big|_{t=0}.\ ] ] note that the right hand side of this last equation is independent of the local section @xmath124 , and hence we have that @xmath304 thus we may unambiguously write @xmath305 as a well defined vector field on @xmath0 without the need to specify which point in the fibre the supervector @xmath36 was based .
note that this not true for @xmath35 . the maps @xmath47 , @xmath285 and @xmath290 defined in eqs .
( [ eqn : deflg][eqn : defrgl ] ) , respectively , can be extended to maps on associated bundles as follows .
consider a local section @xmath306 $ ] of some general associated bundle .
we then define the maps @xmath307 , @xmath308 and @xmath309 by @xmath310 & \hspace{5pt } \mapsto \hspace{5pt } & [ ( l_g\big(l(p)\big ) , \xi(p))]\\ \tilde{l}_g^{(l ) } & : [ ( l(p ) , \xi(p ) ) ] & \hspace{5pt } \mapsto \hspace{5pt } & [ ( l_g^{(l)}\big(l(p)\big ) , \xi(p))]\\ \label{eqn : tildergl } \tilde{r}_g^{(l ) } & : [ ( l(p ) , \xi(p ) ) ] & \hspace{5pt } \mapsto \hspace{5pt } & [ ( r_g^{(l)}\big(l(p)\big ) , \xi(p))].\end{aligned}\ ] ] in this section we will discuss properties of the left and right @xmath3-compensators .
recall that the left @xmath3-compensator is defined by the equation @xmath311 now , setting @xmath312 we can rearrange this formula to give @xmath313 but we also have @xmath314 from which we can deduce the relation @xmath315 this relation will be important when considering derivations on local sections of associated bundles .
next we shall derive the composition rule for the left @xmath3-compensators .
we have @xmath316 on the other hand we have @xmath317 now , from eqs .
( [ eqn : complefth1],[eqn : complefth2 ] ) , we see that @xmath318 and hence we can deduce from eqs .
( [ eqn : lg1lg2],[eqn : lg1g2 ] ) and eqs .
( [ eqn : complefth1],[eqn : complefth2 ] ) , respectively , @xmath319 now we shall also consider the transformation of @xmath320 under a change of local section @xmath321 , i.e. under a gauge transformation .
we have @xmath322 from eqs .
( [ eqn : lefthcompgauge1],[eqn : lefthcompgauge2 ] ) we thus find @xmath323 in the following we shall consider infinitesimal versions of eqs .
( [ eqn : complgs],[eqn : comprulelefth ] ) and eq .
( [ eqn : tildehgauge ] ) . defining @xmath324 we can write the expansion of @xmath325 for @xmath326 with @xmath327 and @xmath328 to first order as @xmath329 note that using eq .
( [ eqn : comprulelefth ] ) we easily see that @xmath330 is left linear in @xmath41 . in the following we
shall for the ease of notation suppress the @xmath7 dependence in @xmath331 . now using the composition rule eq .
( [ eqn : complg s ] ) and the fact that @xmath332 we find for the infinitesimal version of eq . ( [ eqn : complg s ] ) with @xmath333 and @xmath334 for @xmath335 @xmath336 = - \pi _ * [ a , b]^\flat.\ ] ] this result can also be seen as a consequence of the well definedness of the supervector field @xmath305 , eq .
( [ eqn : notmultiplydefined ] ) , which allows us to take the action of the pushforward under the projection , @xmath337 , inside the lie bracket of eq .
( [ eqn : flatalgebra ] ) . now consider eq .
( [ eqn : comprulelefth ] ) .
we have for the expansion of @xmath338 @xmath339+\ldots .\ ] ] the infinitesimal version of eq .
( [ eqn : comprulelefth ] ) is thus given by @xmath340 ) = \pi _ * b^\flat [ w^{(l)}_l(a ) ] - \pi _ * a^\flat [ w^{(l)}_l(b ) ] + [ w^{(l)}_l(b),w^{(l)}_l(a)].\ ] ] in the literature this last equation is normally referred to as the integrability condition for the left @xmath3-compensator @xcite .
expanding eq .
( [ eqn : tildehgauge ] ) we find for the transformation of @xmath331 under a gauge transformation @xmath341 @xmath342 therefore we see that @xmath331 transforms like a connection under a change of local section . in a similar fashion as for the left @xmath3-compensator we can derive a composition rule for the right @xmath3-compensator , eq .
( [ eqn : righthcomp ] ) , @xmath343 .
we find @xmath344 again proceeding in a similar fashion as in the case of the left @xmath3-compensator we can derive an expression for the transformation properties of the right @xmath3-compensator under a change of local section @xmath345 .
note , however , that in this case also the map @xmath298 will transform under a change of local section
. we find @xmath346 in the following we shall consider the infinitesimal versions of eqs .
( [ eqn : comprgs][eqn : gaugetransformrighthcomp ] ) .
defining @xmath347 we can write the expansion of @xmath343 for @xmath326 with @xmath327 and @xmath328 to first order as @xmath348 note that using eq .
( [ eqn : comphr s ] ) one can show that @xmath349 is left linear in @xmath41 .
in the following we shall for the ease of notation suppress the @xmath7 dependence in @xmath350 .
we shall now show that @xmath351 for @xmath352 is related to the spin connection . in order to do this consider first @xmath353 for @xmath354 .
now , setting @xmath355 and @xmath356 , we have @xmath357 .
clearly the tangent vector to the curve @xmath358 is given by @xmath359 and hence @xmath358 is the horizontal lift of the curve @xmath149 .
also note that @xmath360 .
as such we can identify the right @xmath3-compensator @xmath361 with @xmath362 of eq .
( [ eqn : localconnectionproperty ] ) .
we can thus write @xmath363 and hence @xmath364 on the other hand consider @xmath351 for @xmath365 .
we have @xmath366 and using the fact that @xmath367 we thus find @xmath368 and hence @xmath369 for the ease of notation we shall for the rest of this section drop the explicit @xmath124 dependence on @xmath370 . now consider the infinitesimal versions of eqs .
( [ eqn : comprgs],[eqn : comphr s ] ) .
we find with @xmath333 and @xmath371 @xmath372 & = \pi _ * [ a , b]^\sharp + \pi_*[w^{(l)}_r(a),b]^\sharp - \pi_*[w^{(l)}_r(b),a]^\sharp \\ w^{(l)}_r([a , b ] ) & = [ w^{(l)}_r ( a),w^{(l)}_r ( b ) ] + \pi _ * a^\sharp w^{(l)}_r ( b ) - \pi _ * b^\sharp w^{(l)}_r ( a ) \nonumber \\ \label{eqn : hrinf } & \hspace{12pt } + { } w^{(l)}_r\left ( [ w^{(l)}_r(b),a]\right ) - w^{(l)}_r\left([w^{(l)}_r(a),b ] \right).\end{aligned}\ ] ] now , in the case where @xmath373 we find that eq .
( [ eqn : rginf ] ) corresponds to the expression for the torsion as given in eq .
( [ eqn : comptorsion ] ) , whereas eq .
( [ eqn : hrinf ] ) corresponds to the expression for the curvature as given in eq .
( [ eqn : compcurvature ] ) . the infinitesimal versions of eqs .
( [ eqn : gaugetransformrh],[eqn : gaugetransformrighthcomp ] ) read @xmath374 in the case where @xmath352 we find using @xmath375 , see eq .
( [ eqn : adhpi ] ) , that eq .
( [ eqn : spincongaugetrafo ] ) gives the transformation of the spin connection under gauge transformations , cf.eq .
( [ eqn : gaugetransformconnection ] ) .
finally let us consider the successive action of @xmath285 and @xmath290 on @xmath124 .
proceeding in the same way as when deriving the composition rules for the left @xmath3-compensators , eqs .
( [ eqn : complgs],[eqn : comprulelefth ] ) , we find @xmath376 the infinitesimal versions of eq .
( [ eqn : leftrightcomprulemaps ] ) and eq .
( [ eqn : leftrightcomprule ] ) with @xmath333 and @xmath334 read @xmath377 & = \pi _ * [ w^{(l)}_l(a ) , b]^\sharp\\ \label{eqn : leftrightcomprule1 } [ w^{(l)}_l(a),w^{(l)}_r(b ) ] - \pi_*b^\sharp[w^{(l)}_l(a ) ] & = w^{(l)}_r([w^{(l)}_l(a),b ] ) - \pi _ * a^\flat[w^{(l)}_r(b)].\end{aligned}\ ] ]
when studying the geometry of superspace we do not , in general , have a definition of a metric on the superspace @xcite . thus the notion of isometry from ordinary geometry , i.e. transformations which leave the metric invariant , can not be carried over to supergeometry .
instead we must work with a definition of isometries based on the geometrical objects at hand , that is the frame and connection .
imposing that the frame and connection remain invariant under an isometry turns out to be too restrictive and must be relaxed by demanding them to be invariant only up to a gauge transformation , see e.g. @xcite .
this is required to be a single gauge transformation transforming frame and connection together , not independent transformations for each quantity .
for instance , the map @xmath378 will be an isometry if @xmath379 for some @xmath380 which , as a gauge transformation , need not be constant .
it can be shown that if we impose such a condition on the map @xmath37 for one choice of local section @xmath180 then it will automatically be satisfied for other choices of @xmath180 with a different value for the gauge transformation @xmath253 . as stated earlier the left action @xmath47 on @xmath1 induces a map @xmath295 on the coset space @xmath0 .
such maps can be thought of as isometries of the coset space , as can be demonstrated by considering how the frame and connection transform under the action of @xmath295 .
recall from eq .
( [ eqn : theequation ] ) that the pullback of the maurer - cartan form under a local section provides us with both the local coframe and connection .
thus we will consider how @xmath381 behaves under a pullback by @xmath295 .
consider a curve in the base @xmath96\to g / h$ ] with tangent vector @xmath33 and @xmath382 .
using a matrix representation we have @xmath383 now the curve @xmath384 has tangent vector @xmath385 and thus @xmath386 here we have used eq . ( [ eqn : lgproperty ] ) to obtain the second and third lines , the final line follows from evaluating the derivative and using eq .
( [ eqn : pullbackzeta ] ) . from this
we thus see that @xmath387 if we now decompose this equation into its @xmath64 and @xmath63 parts , we find @xmath388 comparing with eqs .
( [ eqn : isome],[eqn : isomomega ] ) we see that the pulled back coframe and connection from @xmath389 to @xmath7 are simply a gauge transform of the coframe and connection already at @xmath7 ; the parameter of the gauge transformation is given by the @xmath3-compensator @xmath286 . from how the coframe transforms under the pullback by @xmath295
we may deduce how the frame transforms under the pushforward by @xmath295 .
we find @xmath390 the maps @xmath295 therefore are isometries of @xmath0 .
they may be composed as in eq .
( [ eqn : complg s ] ) and thus form a group of isometries isomorphic to @xmath1 . the maps @xmath295 may , however , not be all the isometries .
for instance , in the case when the normalizer @xmath391 is non - trivial then right multiplication in @xmath1 by an element @xmath392 results in a well defined map on the coset space which , if non - trivial , i.e. @xmath393 , also satisfies the conditions for it to be an isometry . for a more detailed discussion of this see @xcite . for an infinitesimal isometry given by @xmath295 with @xmath394 we have the associated supervector field @xmath305 , c.f.eq .
( [ eqn : pistaraflatdefinition ] ) .
the supervectors @xmath305 are therefore killing supervectors for the coset space , i.e. supervectors which give infinitesimal isometries .
we see from eq .
( [ eqn : algebrapiflats ] ) that the killing supervectors satisfy an algebra .
the set of @xmath395 , @xmath25 , form a set of independent killing supervectors , and from eq .
( [ eqn : algebrapiflats ] ) satisfy @xmath396 = -f_{pq}{}^r \pi_\ast t_r^\flat.\ ] ] the definition of killing supervectors will be discussed in more detail in section [ sec : killing ] .
in this section we shall consider derivations , such as the covariant derivative , the lie derivative and the so - called @xmath3-covariant lie derivative on associated bundles .
a derivation , or more precisely a graded derivation , is here defined as a linear map on an abstract algebra satisfying the graded leibniz rule . in the following
we shall define the covariant derivative @xmath397 on a local section @xmath235 $ ] of a general associated bundle in the direction of the push - forward of an even horizontal vector @xmath398 in terms of the map @xmath290 . before we do this
let us , however , first review the standard definition of the covariant derivative on associated bundles , see @xcite . consider a curve @xmath149 in the base with @xmath399 $ ] and @xmath400 .
we can then write , using eq .
( [ eqn : horizontallift ] ) , @xmath401 now , setting @xmath402 , we have for the standard definition of the covariant derivative @xmath403 where @xmath33 is the tangent vector to @xmath149 at @xmath7 . from this
we see that a local section @xmath404 is parallel transported along @xmath149 if @xmath405 is constant along @xmath149 .
it is easy to see that the covariant derivative does not depend on the specific choice of horizontal lift @xmath358 . on the other hand we shall now see that one can also define the covariant derivative of a local section @xmath259 in terms of the map @xmath290 .
we will define @xmath406 using the definition of the map @xmath407 on @xmath259 , see eq .
( [ eqn : tildergl ] ) , this can be rewritten as @xmath408 note that in deriving this we have used @xmath409 as well as the equivalence relation eq .
( [ eqn : equivrelvector ] ) . noting that @xmath360 and @xmath410 we easily see from eq .
( [ eqn : covversusnakaharacov ] ) that our definition of the covariant derivative , eq .
( [ eqn : covder ] ) , is in the specific case of the vector @xmath411 equivalent to the standard definition given by eq .
( [ eqn : covdernakahara ] ) .
note that although the range of the map @xmath412 is considered to be restricted to @xmath284 this does not pose a problem for our definition of the covariant derivative as @xmath413 can always be chosen sufficiently small such that @xmath414 .
now , from eq .
( [ eqn : covversusnakaharacov ] ) we easily find @xmath415 + \rho\big(\omega^{(l)}(\pi_*(k^\sharp|_{l(p)}))\big ) \xi(p)\,\big ) \big\rbrack.\end{aligned}\ ] ] here we consider @xmath416 in the representation appropriate for acting on @xmath417 .
it is easy to see that the covariant derivative is invariant under the equivalence transformations on associated bundles , see eq .
( [ eqn : equivrel ] ) .
we have @xmath418 & \nonumber \\ & \hspace{-80pt } = \lim_{\epsilon \to 0 } \frac{1}{\epsilon } \big(\big\lbrack\big(\,(r_{e^{\epsilon k}}^{(l)})^{-1}\big(l(r^{(l)}_{e^{\epsilon k}}(p))h\big)\,,\ , \rho(h^{-1})\xi(r^{(l)}_{e^{\epsilon k}}(p))\,\big)\big\rbrack \nonumber \\ & \hspace{-46pt } - { } \big\lbrack\big(l(p)h,\rho(h^{-1})\xi(p)\big)\big\rbrack\big ) \nonumber \\ & \hspace{-80pt } = \lim_{\epsilon \to 0 } \frac{1}{\epsilon } \big(\big\lbrack\big(\,l(p)\tilde{h}^{(l)}_r(p , e^{\epsilon k})^{-1}h\,,\,\rho(h^{-1})\xi(r^{(l)}_{e^{\epsilon k}}(p))\,\big)\big\rbrack \nonumber \\ & \hspace{-46pt } - { } \big\lbrack\big(l(p)h,\rho(h^{-1})\xi(p)\big)\big\rbrack\big ) \nonumber \\ \nonumber & \hspace{-80pt } = \nabla_{\pi_*\left(k^\sharp|_{l(p)}\right ) } [ ( l(p),\xi(p))].\end{aligned}\ ] ] the covariant derivative of @xmath259 is therefore , as a section , well defined .
using @xmath419 and @xmath420 , we have @xmath421 + \rho\big(\omega^{(l)}_a\big ) \xi(p)\,\big ) \big\rbrack,\ ] ] which will transform under a change of local section as @xmath422 from eq .
( [ eqn : covdercomp1 ] ) we see that our definition of the covariant derivative , eq .
( [ eqn : covder ] ) , gives us an expression for the covariant derivative in the direction of the basis vectors @xmath156 .
as such it extends to a derivative in the direction of an arbitrary vector field @xmath423 , although our initial definition was only given for vector fields @xmath424 with @xmath168 constant . note that for convenience of notation we shall for the rest of this section drop the explicit @xmath124 dependence on the vectors @xmath425 as well as on @xmath156 . as a practical example
let us consider calculating the covariant derivative of a local section of a contravariant vector bundle @xmath426 = x^a e_a$ ] .
we have @xmath427 where we have used the equivalence relation for tensor bundles , see eqs .
( [ eqn : equivreltensor1],[eqn : equivreltensor2 ] ) . using eqs .
( [ eqn : expansionhr],[eqn : infinitesimalcoadjoint ] ) we can expand @xmath428 as @xmath429 where we have also dropped the @xmath124 dependence on @xmath181 . using eq .
( [ eqn : expansionf(r ) ] ) we can expand @xmath430 as @xmath431 + \mathcal{o}(\epsilon^2),\ ] ] which allows us to rewrite eq .
( [ eqn : covdervector1 ] ) as @xmath432 + x^b(p ) \omega^{i}(\pi_*k^\sharp)f_{ib}{}^a\big\}\big)\big\rbrack.\ ] ] finally let us consider the commutator of two covariant derivatives @xmath433 s(p ) = \lim_{\stackrel{\scriptstyle \epsilon_1 \to 0}{\scriptstyle \epsilon_2 \to 0 } } \frac{1}{\epsilon_1 \epsilon_2}\big ( \big\lbrack\big ( l(p ) , \\ \hspace{10pt } \rho(\tilde{h}_r^{(l)}(p , e^{\epsilon_1 k_1})^{-1 } ) \rho(\tilde{h}_r^{(l)}(r_{e^{\epsilon_1k_1}}(p),e^{\epsilon_2 k_2})^{-1 } ) \xi(r_{e^{\epsilon_2k_2}}(r_{e^{\epsilon_1k_1}}(p ) ) ) \\ { } -\rho(\tilde{h}_r^{(l)}(p , e^{\epsilon_2 k_2})^{-1 } ) \rho(\tilde{h}_r^{(l)}(r_{e^{\epsilon_2k_2}}(p),e^{\epsilon_1 k_1})^{-1 } ) \xi(r_{e^{\epsilon_1k_1}}(r_{e^{\epsilon_2k_2}}(p ) ) ) \big)\big\rbrack\big).\end{gathered}\ ] ] expanding and taking the limit we have @xmath433 s(p ) = \big\lbrack \big(l(p),\ , [ \omega(\pi _ * k_1^\sharp),\omega(\pi _ * k_2^\sharp)]\xi(p ) \\ { } + [ \pi _ * k_1^\sharp,\pi _ * k_2^\sharp]\xi(p ) + \pi_*k_1^\sharp[\omega(\pi _ * k_2^\sharp)]\xi(p ) - \pi_*k_2^\sharp[\omega(\pi _ * k_1^\sharp)]\xi(p ) \big ) \big\rbrack.\end{gathered}\ ] ] note that for the ease of notation we have suppressed the representation @xmath232 on @xmath434 .
now , using the expressions for the curvature as given in eq .
( [ eqn : rxy ] ) , we can rewrite this last equation as @xmath433 s(p ) = \big\lbrack \big(l(p ) , \\ r(\pi _ * k_1^\sharp , \pi _ * k_2^\sharp)\xi(p ) + [ \pi _ * k_1^\sharp,\pi _ * k_2^\sharp]\xi(p ) + \omega([\pi _ * k_1^\sharp,\pi _ * k_2^\sharp])\xi(p))\big ) \big\rbrack\end{gathered}\ ] ] and hence we finally have , using the expression for the covariant derivative as given in eq .
( [ eqn : covdercomp ] ) , @xmath435 s(p ) = r(\pi _ * k_1^\sharp , \pi _ * k_2^\sharp)s(p ) + \nabla_{[\pi _ * k_1^\sharp,\pi _ * k_2^\sharp ] } s(p),\ ] ] where @xmath436 is an abbreviation for the action of @xmath437 on the section @xmath259 with @xmath438 .
now , setting @xmath439 and @xmath440 we can rewrite the left hand side of this equation as @xmath441 s(p ) & = x^a ( \nabla_a y)^b \nabla_b s(p ) - y^b ( \nabla_b x)^a \nabla_a s(p ) \nonumber \\ & \hspace{15pt } + y^b x^a [ \nabla_a , \nabla_b ] s(p)\nonumber \\ & = y^b x^a [ \nabla_a,\nabla_b ] s(p ) \nonumber \\ & \hspace{15pt } - { } y^b x^a \left(\omega_{ab}{}^c \nabla_c + ( -1)^{ab } \omega_{ba}{}^c
\nabla_c\right ) s(p ) \nonumber,\end{aligned}\ ] ] where we have used eq . ( [ eqn : covder_vector ] ) for constant @xmath33 .
the right hand side of eq .
( [ eqn : commcovdev0 ] ) can be rewritten as @xmath442 } = y^b x^a\left ( r_{ab } + \mathcal{c}_{ab}{}^c \nabla_c \right ) \nonumber\ ] ] and we hence find in total , using the component expression of the torsion , eq .
( [ eqn : comptorsion ] ) , @xmath443 = r_{ab } + t_{ab}{}^c \nabla_c .\ ] ] in this section we will introduce the lie derivative on a local section @xmath259 in the direction of an isometry .
we define @xmath444 we can rewrite the lie derivative as @xmath445 one should note the similarity to the expression of the covariant derivative given in eq .
( [ eqn : covversusnakaharacov ] ) .
note also that , although the range of the map @xmath446 is considered to be restricted to @xmath284 , this does not pose a problem for our definition of the lie derivative as @xmath413 can always be chosen sufficiently small such that @xmath447 .
now we easily find @xmath448 + \rho\big(w^{(l)}_l(a)\big ) \xi(p)\,\big ) \big\rbrack,\end{aligned}\ ] ] where we have used eqs .
( [ eqn : pistaraflatdefinition],[eqn : defw ] ) . here
we consider @xmath449 to be in the representation appropriate for acting on @xmath417 .
it is easy to see that the lie derivative is invariant under the equivalence transformations @xmath450 = [ ( l(p)h , \rho(h^{-1})\xi(p))]$ ] .
the lie derivative of @xmath259 is therefore , as a section , well defined .
again for the ease of notation we shall for the rest of this section drop the explicit @xmath124 on the @xmath156 .
as an example we shall now calculate the lie derivative of a vector and a one - form , respectively . first consider a local section of a vector bundle @xmath451 = x^a e_a$ ] .
we have @xmath452 where we have used the equivalence relation for tensor bundles , see eqs .
( [ eqn : equivreltensor1],[eqn : equivreltensor2 ] ) .
using eqs .
( [ eqn : expansionhl],[eqn : infinitesimalcoadjoint ] ) we can expand @xmath453 as @xmath454 where we have now also dropped the @xmath124 dependence on @xmath455 . using eq .
( [ eqn : pistaraflatdefinition ] ) we can expand @xmath456 as @xmath457 + \mathcal{o}(\epsilon^2),\ ] ] which allows us to rewrite eq .
( [ eqn : lie_vector1 ] ) as @xmath458 + x^b(p ) w_l^{i}(a)f_{ib}{}^a\big\}\big)\big\rbrack.\ ] ] in the particular case of the lie derivative of the basis vector @xmath459 we find from this @xmath460 by a similar calculation as in the case of the lie derivative of a vector we find for the lie derivative of a one - form @xmath461 = e^a \phi_a $ ] @xmath462 - w_l^{i}(a)f_{ia}{}^b \phi_b(p ) \big\}\big)\big\rbrack\end{aligned}\ ] ] and hence in the particular case of the lie derivative of the basis vector @xmath463 @xmath464 now , in the case of the connection one - from @xmath181 we find from eq .
( [ eqn : lie_form ] ) together with the composition rule of the right and left @xmath3-compensators , see eq .
( [ eqn : leftrightcomprule1 ] ) , @xmath465 - w_l^{i}(a)f_{ia}{}^b \omega_b(p ) \big\}\big)\big\rbrack \nonumber \\ & = \big\lbrack\big(l(p),\big\ { e_a [ \rho\big(w_l(a)\big ) ] - [ \rho\big(w_l(a)\big ) , \omega_a ] \big\}\big)\big\rbrack.\end{aligned}\ ] ] now consider the algebra of two lie derivatives .
we find , writing for simplicity @xmath466 instead of @xmath467 , @xmath468 s(p ) = \big\lbrack\big(l(p)\,\,,\,\ , [ \pi _ * a^\flat , \pi _ * b^\flat]\xi(p ) \\ + { } ( \pi _ * a^\flat [ w_l(b ) ] - \pi _ * b^\flat [ w_l(a ) ] + [ w_l(a),w_l(b ) ] ) \xi(p)\big)\big\rbrack\end{gathered}\ ] ] and hence , using eq .
( [ eqn : intcondw1 ] ) , we find @xmath469 s(p ) & = \big\lbrack\big(l(p)\,\,,\,\ , [ \pi _ * a^\flat , \pi _ * b^\flat]\xi(p ) + w_l([b , a])\xi(p)\big)\big\rbrack.\end{aligned}\ ] ] now , noting that the algebra element corresponding to the vector @xmath470 = \pi _ * [ b , a]^\flat$ ] is given by @xmath471 $ ] , cf.eq .
( [ eqn : algebrapiflats ] ) , we find
@xmath472 = \mathcal{l}_{[\pi _ * a^\flat , \pi _ * b^\flat]}.\ ] ] finally let us consider the commutator of the lie derivative with the covariant derivative on a local section @xmath473 $ ] . we find @xmath474 s(p ) & = \big\lbrack\big(l(p)\ , , \,\ , [ \pi _ * a^\flat , \pi _ * b^\sharp ] \xi(p ) + \pi _ * a^\flat [ \omega(\pi _ * b^\sharp)]\xi(p ) \nonumber \\ & \hspace{55pt } - { } \pi _ * b^\sharp[w_l(a)]\xi(p ) + [ w_l(a ) , \omega ( \pi _ * b^\sharp)]\xi(p)\big)\big\rbrack \nonumber \\ & = \big\lbrack\big ( l(p)\,,\,\ , [ \pi _ * a^\flat , \pi _ * b^\sharp ] \xi(p ) + \omega([\pi _ * a^\flat , \pi _ * b^\sharp])\xi(p ) \big)\big\rbrack \nonumber\\ & = \nabla_{[\pi _ * a^\flat , \pi _ * b^\sharp ] } s(p ) , \nonumber\end{aligned}\ ] ] where we have used eqs .
( [ eqn : leftrightcomprulemaps1],[eqn : leftrightcomprule1 ] ) .
we thus have @xmath475 s(p ) = \nabla_{(\mathcal{l}_{\pi _ * a^\flat } \pi _ * b^\sharp ) } s(p).\ ] ] now , setting @xmath476 , @xmath168 constant , we have , evaluating the left hand side of eq .
( [ eqn : commutatorgradlie ] ) directly @xmath477 s(p ) = ( \mathcal{l}_{\pi _ * a^\flat } \pi _ * b^\sharp)^a \nabla_{a}s(p ) + x^a[\mathcal{l}_{\pi _ * a^\flat } , \nabla_{a } ] s(p).\ ] ] combining this with eq .
( [ eqn : commutatorgradlie ] ) we finally find @xmath478 = 0.\ ] ] in this section we shall define the so - called @xmath3-covariant lie derivative , the characteristic property of which is that when differentiating the frame it gives zero .
we define the @xmath3-covariant lie derivative of a section @xmath259 of a general tensor bundle in the direction of an isometry as @xmath479 we can rewrite the @xmath3-covariant lie derivative as @xmath480 where we have used eq .
( [ eqn : tildehlrelinverse ] ) . again note that , although the range of the map @xmath481 is considered to be restricted to @xmath284 , this does not pose a problem for our definition of the @xmath3-covariant lie derivative as @xmath413 can always be chosen sufficiently small such that @xmath482 .
now we immediately find from eq .
( [ eqn : hliederddt ] ) @xmath483\,\big ) \big\rbrack.\ ] ] it is easy to see that the @xmath3-covariant lie derivative is invariant under the equivalence transformations on associated bundles , see eq .
( [ eqn : equivrel ] ) .
we have @xmath484 & \nonumber \\ & \hspace{-70pt } = \lim_{\epsilon \to 0 } \frac{1}{\epsilon } \big ( \big\lbrack\big ( l^{(l)}_{e^{-\epsilon a } } \left(l(l_{e^{\epsilon a}}(p))h\right ) , \rho(h^{-1})\xi\left(l_{e^{\epsilon a}}(p)\right ) \big)\big\rbrack \nonumber \\ & \hspace{-70pt } \hspace{34pt } - { } \big\lbrack\big(l(p)h , \rho(h^{-1})\xi(p ) \big)\big\rbrack \big ) \nonumber \\ & \hspace{-70pt } = \lim_{\epsilon \to 0 } \frac{1}{\epsilon } \big ( \big\lbrack\big ( l(p)h,\rho(h^{-1})\xi\left(l_{e^{\epsilon a}}(p)\right ) \big)\big\rbrack \nonumber \\ & \hspace{-70pt } \hspace{34pt } - { } \big\lbrack\big(l(p)h , \rho(h^{-1})\xi(p ) \big)\big\rbrack \big ) \nonumber \\ & \hspace{-70pt } = \lim_{\epsilon \to 0 } \frac{1}{\epsilon } \big\lbrack\big ( l(p),\xi\left(l_{e^{\epsilon a}}(p)\right ) - \xi(p ) \big)\big\rbrack \nonumber \\ & \hspace{-70pt } = \mathbbm{l}^{(l)}_{\pi _ * a^\flat } [ ( l(p),\xi(p ) ) ] .
\nonumber\end{aligned}\ ] ] on the other hand we find for the transformation of @xmath485 under gauge transformations @xmath486
i.e.@xmath487 from eq .
( [ eqn : hcovpi * ] ) we easily find for the algebra of two @xmath3-covariant derivatives @xmath488 = \mathbbm{l}^{(l)}_{[\pi _ * a^\flat,\pi _ * b^\flat]}.\ ] ] now , from eq .
( [ eqn : hcovpi * ] ) we immediately find that the @xmath3-covariant lie derivative of the frame @xmath156 gives zero @xmath489\right\}\,\big ) \big\rbrack = 0.\ ] ] the @xmath3-covariant lie derivative of the spin connection @xmath120 is given by @xmath490\right\ } \big ) \big\rbrack \nonumber \\ & = \big\lbrack \big(l(p ) , \left\{e_a^{(l)}[w_l^{(l)}(a ) ] - [ w_l^{(l)}(a),\omega_a^{(l ) } ] + w_l^{(l)i}(a ) f_{ia}{}^b \omega^{(l)}_b \right\}\big ) \big\rbrack,\end{aligned}\ ] ] where we have used the infinitesimal composition rule for the left and right @xmath3-compensators , eq .
( [ eqn : leftrightcomprule1 ] ) .
@xmath3-covariant lie derivatives have been mentioned in various places in the literature , see for example @xcite . in this section
we shall show how our definition relates to those given in the literature . in order to do this
we shall first derive a relation between the ordinary lie derivative and the @xmath3-covariant lie derivative on a general section of an associated bundle . recall the expression for the lie derivative given in eq .
( [ eqn : liecomp ] ) , @xmath491 + \rho\big(w^{(l)}_l(a)\big ) \xi(p)\,\big ) \big\rbrack.\ ] ] using the definition of the action of the algebra of @xmath3 on a local section , see eq .
( [ eqn : deftilderh ] ) , and the expression for the @xmath3-covariant lie derivative given in eq .
( [ eqn : hcovpi * ] ) we find from this @xmath492 from this we see that the lie derivative consists of two parts , namely the @xmath3-covariant lie derivative and a gauge transformation .
let us understand this in more detail .
first consider the @xmath3-covariant lie derivative on a local section @xmath493 $ ] .
this measures the difference between @xmath494 at @xmath495 and @xmath417 at @xmath124 by dragging @xmath494 back constantly along the curve @xmath496 , see figure [ fig : drag ] .
in contrast , the ordinary lie derivative measures the difference between @xmath494 at @xmath495 and @xmath417 at @xmath124 by dragging @xmath494 back constantly along the curve @xmath497 . alternatively this can be understood as dragging @xmath494 back constantly first along the local section @xmath124 , namely along the curve @xmath498 , and then along the curve @xmath499 , see figure [ fig : drag ] . as such the lie derivative splits up into two parts : the first one , the @xmath3-covariant lie derivative , measures the change along the local section @xmath124 , the second one measures the change in the direction ` perpendicular ' to the local section @xmath124 .
now consider the @xmath3-covariant lie derivative .
this is given by , see eq .
( [ eqn : hcovpi * ] ) , @xmath500)].\ ] ] recall that @xmath501 stands for the components of the supertensor @xmath259 with respect to the basis of the @xmath156 .
e.g. , for @xmath502 a vector , @xmath417 stands for the components @xmath168 of this vector in the basis @xmath156 , see section [ sec : supertensorbundles ] . as such @xmath503 $ ]
is equal to the lie derivative of the _ components _ of the supertensor @xmath259 .
e.g. , in the case of @xmath504 a vector , we have @xmath505 = \ell_{\pi _ * a^\flat } x^a(p)$ ] , where we wrote the lie derivative of the _ scalar _ quantity @xmath168 as @xmath506 in order to distinguish this from @xmath507 , i.e. from the @xmath41th component of the lie derivative of @xmath33 .
note that the difference we make between the lie derivative @xmath508 and the usual lie derivative @xmath509 is a purely notational one .
we can thus rewrite the @xmath3-covariant lie derivative as @xmath510\ ] ] now let us consider the lie derivative . using the above notation we can define @xmath511 where @xmath512 transforms the tangent space indices in the way following from eq .
( [ eqn : equivreltensor2 ] ) .
this allows us to rewrite the lie derivative of a local section @xmath259 as @xmath513.\ ] ] in the literature it is @xmath514 , defined in eq .
( [ eqn : hcovliterature ] ) , that is commonly referred to as the @xmath3-covariant lie derivative .
one should note the similarity of eq .
( [ eqn : hcovliterature ] ) to the expression for the lie derivative in terms of the @xmath3-covariant lie derivative , see eq .
( [ eqn : rel_lieversliecomp ] ) . as an example
consider the lie derivative and the @xmath3-covariant lie derivative , respectively , of @xmath502 a vector .
we find @xmath515 where @xmath516 + x^b w_l^{(l)i}(a)f_{ib}{}^a.\ ] ] now consider the covariant derivative .
we have , see eq .
( [ eqn : covdercomp1 ] ) , @xmath517 + \rho\big(\omega^{(l)}_a\big ) \xi(p)\,\big ) \big\rbrack\ ] ] and setting @xmath518 we can rewrite the covariant derivative as @xmath519 now , considering the commutator of the covariant derivative with the lie derivative we have from eq .
( [ eqn : commliecov0 ] ) @xmath520s(p ) = \big[\big(l(p ) , [ \mathbbm{l}^{(l)}_{\pi _ * a^\flat } , \mathcal{d}^{(l)}_a]\xi(p)\big)\big ] = 0\ ] ] and hence @xmath521 = 0.\ ] ]
we have , in section [ sec : isometries ] , touched upon the notion of killing supervectors , the supervectors associated to infinitesimal isometries . in this section
we shall analyze in more detail how the killing supervectors may be defined , particularly in terms of the derivations we discussed in section [ sec : derivations ] .
let us first introduce what we shall call the _ generalized lie derivative_. just as the lie derivative and covariant derivative were constructed from the action of certain local bundle maps so will the generalized lie derivative . the map we use will be a local bundle map of the form @xmath522 here @xmath523 is a one parameter family of maps on the base and the maps @xmath524 are a one parameter family of @xmath3-valued functions .
the map @xmath525 is required to satisfy @xmath526 , and so , associated with the map is a supervector field on @xmath284 defined by @xmath527={\frac{\mathrm{d}}{\mathrm{d}t}}f(f_t^{(l)}(g))\big|_{t=0}.\ ] ] following from the decomposition of the map @xmath525 as mentioned above we have a decomposition of the supervector field @xmath213 as @xmath528 here @xmath529 is the supervector associated to the map @xmath530 on the base and @xmath3 is the algebra element associated to @xmath531 given by @xmath532 .
it can be shown that the supervector field @xmath213 at points off the local section is given by @xmath533 as a consequence of this @xmath534 is a well defined supervector field on the base manifold , without the need to specify from which point the supervector @xmath213 was taken to originate , analogously to the situation for @xmath305 . the map @xmath525 can then be extended to a map on an associated bundle analogously to eqs .
( [ eqn : tildelg][eqn : tildergl ] ) @xmath535 \mapsto [ ( f_t^{(l)}(l(p)),\xi(p))].\ ] ] we then define the generalized lie derivative of a ( local ) section @xmath259 of the associated bundle by @xmath536 note that here we have indexed the generalized lie derivative with the supervector @xmath213 . to see how @xmath537 depends on the components @xmath33 and @xmath3 , first note that @xmath538 using this we find from the definition of @xmath537 that @xmath539 - \left[\big ( l(p ) , \xi(p)\big)\right]\right ) \\ \nonumber & = \lim_{\epsilon\to 0 } \frac{1}{\epsilon } \big ( \big[\big ( l(p ) , \xi(f_\epsilon(p ) ) - \xi(p)\big)\big ] \\
\nonumber & \hspace{2cm}+ \big[\big ( l(p ) , ( \rho(\tilde{h}_\epsilon(p))-1 ) \xi(f_\epsilon(p))\big)\big]\big ) \\ \label{eqn : kxsplit } & = \big(\mathbbm{l}^{(l)}_x + \tilde{r}^{(l)}_h \big ) s(p).\end{aligned}\ ] ] in the last line we have introduced a generalization of the @xmath3-covariant lie derivative , see eq .
( [ eqn : hcovdef ] ) , to act in the direction of an arbitrary supervector field @xmath33 rather than just in the direction of a killing supervector @xmath305 @xmath540 \big)\big].\ ] ] also we have used the map @xmath437 defined in eq .
( [ eqn : deftilderh ] ) for the algebra element @xmath3 defined by @xmath541 .
( [ eqn : kxsplit ] ) should be compared to the similar result for the lie derivative , eq .
( [ eqn : rel_lieversliecomp ] ) .
note that @xmath537 may or may not depend on the local section , we will not explicitly indicate this dependence .
the generalized lie derivatives can be shown to form an algebra @xmath542=\mathcal{k}_{[u , v]}.\ ] ] for the supervector @xmath121 we will write the decomposition , eq .
( [ eqn : vdecomp ] ) , as @xmath543 , and similarly for the supervectors @xmath213 and @xmath544 $ ]
. then , the algebra of the generalized lie derivatives decomposes as @xmath545}=[x_u , x_v ] \\ \label{eqn : genderivalgcomp2 } h_{[u , v]}=x_u[h_v ] - x_v[h_u ] + [ h_u , h_v].\end{gathered}\ ] ] these equations can be seen to encompass the various properties of the left and right @xmath3-compensators discussed in section [ sec : propertieshcompensators ] .
for instance , if we take the supervectors @xmath546 and @xmath547 then @xmath544=[b , a]^\flat$ ] .
the decomposition gives @xmath548 and @xmath549 , and similarly for @xmath213 and @xmath544 $ ] .
using these values we see that eqs .
( [ eqn : genderivalgcomp1],[eqn : genderivalgcomp2 ] ) give precisely eqs .
( [ eqn : algebrapiflats],[eqn : intcondw1 ] ) . following a similar approach with more elaborate choices of the supervectors @xmath121 and @xmath213 we
may likewise obtain eqs .
( [ eqn : rginf],[eqn : hrinf ] ) and eqs .
( [ eqn : leftrightcomprulemaps1],[eqn : leftrightcomprule1 ] ) .
we see from eq .
( [ eqn : kxsplit ] ) that the action of @xmath537 can be thought of as comprised of two parts .
the first part , @xmath550 , can be thought of as arising from an infinitesimal general coordinate transformation in the direction of the supervector @xmath33 .
the second part , @xmath551 , can be thought of as arising from an infinitesimal local gauge transformation .
thus @xmath537 can be thought of as giving the general infinitesimal transformation of a section .
this is also apparent from the form of the map @xmath525 that was used to define @xmath537 .
we seek a definition of killing supervectors which is consistent with our notion of infinitesimal isometries as discussed in section [ sec : isometries ] . since @xmath537 represents a general infinitesimal transformation we would like to find a condition on @xmath537 such that it represents an infinitesimal isometry .
once we have this , then the supervector field @xmath33 in the decomposition eq .
( [ eqn : vdecomp ] ) will be the desired killing supervector .
recall from section [ sec : isometries ] that we defined isometries to be the group of transformations which leave the supergeometry , i.e. the frame and connection , invariant up to a single gauge transformation .
now the covariant derivative is a quantity which contains both the frame and the connection , thus we would suspect that there is some way of utilizing the covariant derivative to give a condition for @xmath537 to be an infinitesimal isometry .
now , recall that the lie derivative in the direction @xmath305 commutes with the covariant derivative , eq .
( [ eqn : commliecov0 ] ) . with this in mind
let us consider the commutator of the covariant derivative with the generalized lie derivative .
we have @xmath552 s(p ) & = \mathcal{k}_v \big[\big ( l(p ) , ( e^{(l)}_a + \omega^{(l)}_a ) \xi(p ) \big)\big ] \\
\nonumber & \hspace{1cm}- \nabla^{(l)}_a \big[\big ( l(p ) , ( x + h ) \xi(p ) \big)\big ] \\ \nonumber & = \big[\big ( l(p ) , \big([x , e^{(l)}_a ] - v^i f_{ia}{}^b e^{(l)}_b + x[\omega^{(l)}_a ] - e^{(l)}_a[h ] \\ \label{eqn : kxdelcommutator } & \hspace{1 cm } + [ h,\omega^{(l)}_a ] - v^if_{ia}{}^b\omega^{(l)}_b\big ) \xi(p ) \big)\big],\end{aligned}\ ] ] where we have taken the algebra valued quantities @xmath553 and @xmath554 to be acting in the appropriate representation . thus supposing we impose the condition @xmath555
= 0\ ] ] then we see from eq .
( [ eqn : kxdelcommutator ] ) that this implies @xmath556 & = v^i f_{ia}{}^b e^{(l)}_b , \\ \label{eqn : lxomegaa } x[\omega^{(l)}_a ] - v^if_{ia}{}^b\omega^{(l)}_b & = e^{(l)}_a[h ] - [ h,\omega^{(l)}_a].\end{aligned}\ ] ] now , we note that ( and @xmath557 ) in an arbitrary direction @xmath33 as opposed to @xmath305 , this is defined in the usual way when acting on vectors , scalars and forms . ]
@xmath558 $ ] , thus the first equation gives us an expression for the lie derivative of the frame .
also we have @xmath559 & = \ell_x \big(\omega^{(l)}(e^{(l)}_a)\big ) \\ \nonumber & = \big(\mathcal{l}_x\omega^{(l)}\big)(e^{(l)}_a ) + \omega^{(l ) } \big ( \mathcal{l}_x e^{(l)}_a \big ) \\ \label{eqn : xomegaa } & = \big ( \mathcal{l}_x\omega^{(l ) } \big ) ( e^{(l)}_a ) + v^i f_{ia}{}^b \omega^{(l)}_b,\end{aligned}\ ] ] where in the last line we have used the expression for @xmath560 given by eq .
( [ eqn : lxea ] ) . using eq .
( [ eqn : xomegaa ] ) we see that eq .
( [ eqn : lxomegaa ] ) gives us an expression for the @xmath41th component of the lie derivative of @xmath120 .
thus in total we may rewrite eqs .
( [ eqn : lxea],[eqn : lxomegaa ] ) as @xmath561.\end{aligned}\ ] ] these equations are simply the first order contributions to @xmath562 if we compare this result to eqs .
( [ eqn : isome],[eqn : isomomega ] ) we see that infinitesimally the transformation @xmath563 represents an isometry , as under its action the frame and connection both transform by the gauge transformation given by @xmath564 . based on these considerations
we take eq .
( [ eqn : killingcommutator ] ) as defining the killing supervectors : the supervector @xmath565 associated with a transformation @xmath537 is a killing supervector if the transformation @xmath537 commutes with the covariant derivative @xmath566 .
the advantage of this definition of killing supervectors is that it is easily generalized to superspaces which are not written as a coset space .
so long as we have a covariant derivative we just seek the infinitesimal combined coordinate and gauge transformation which commutes with it .
this is the approach taken in @xcite , however there the derivations used are viewed as acting on the components of a section rather than on the section itself .
we know from section [ sec : isometries ] that the supervector fields @xmath305 are killing supervectors of the coset space @xmath0 .
we would like to see how we may obtain these killing supervectors from eq .
( [ eqn : killingcommutator ] ) .
let us first start by rewriting eq .
( [ eqn : killingcommutator ] ) as , cf .
( [ eqn : commutatorgradlie ] ) , @xmath567 = \nabla_{(\mathcal{k}_v\pi_\ast b^\sharp ) } , \qquad \forall b \in\mathfrak{k}\ ] ] which is easily checked noting that @xmath568 for some constants @xmath569 .
note we again here use the shorthand of dropping the dependence on @xmath124 in the vector @xmath570 .
the supervector @xmath213 will be decomposed into components @xmath33 and @xmath3 as in eq .
( [ eqn : vdecomp ] ) .
then as the @xmath569 are constants we have that @xmath571 , hence @xmath572^\sharp.\ ] ] then , either by direct calculation or by using eqs .
( [ eqn : genderivalgcomp1],[eqn : genderivalgcomp2 ] ) , we see that eq .
( [ eqn : altkillingcommutator ] ) decomposes into the following two conditions @xmath573^\sharp = [ x,\pi_\ast b^\sharp ] \\ \label{eqn : kc2 } \omega^{(l)}(\pi_\ast[h , b]^\sharp ) = x[\omega^{(l)}(\pi_\ast b^\sharp ) ] - \pi_\ast b^\sharp [ h ] + [ h,\omega^{(l)}(\pi_\ast b^\sharp)],\end{gathered}\ ] ] which must be satisfied for all possible choices of the algebra element @xmath574 .
we know from eqs .
( [ eqn : leftrightcomprulemaps1],[eqn : leftrightcomprule1 ] ) that a solution to these conditions is @xmath575 and @xmath576 for some algebra element @xmath41 .
we shall now show that all solutions to these equations can be expressed in this form .
stated differently , we will show that the unique solution to eq .
( [ eqn : killingcommutator ] ) is given by @xmath577 and the killing supervectors are thus of the form @xmath305 .
let us expand @xmath578 and @xmath554 , then eqs .
( [ eqn : kc1],[eqn : kc2 ] ) may be rewritten as @xmath579 & = x^b [ e_b , \pi_\ast b^\sharp]^a - v^i(\pi_\ast[h_i , b]^\sharp)^a \\
\nonumber \pi_\ast b^\sharp [ v^i ] & = x^ae_a[\omega^i(\pi_\ast b^\sharp ) ] + v^j[h_j,\omega(\pi_\ast b^\sharp)]^i - v^j\omega(\pi_\ast[h_j , b]^\sharp)^i,\end{aligned}\ ] ] which should be satisfied for all choices of @xmath580 . as usual
we drop the dependence on @xmath124 for the vectors @xmath570 .
thus , if we group the components into a single object @xmath581 these equations take the simple form @xmath582 + z^qm_q{}^p(b ) = 0 , \qquad \forall b\in\mathfrak{k}\ ] ] where the objects @xmath583 depend linearly on the choice of @xmath574 , they are also functions of the frame and connection . this equation is linear and homogeneous in @xmath584 , thus solutions may be combined linearly to give other solutions .
clearly also @xmath585 is a solution for all choices of @xmath574 .
in fact we already have a whole family of solutions parameterized by the algebra elements @xmath34 , we will denote these solutions by @xmath586 whose components are @xmath587 and @xmath588 .
we will now show that all solutions are of this type .
suppose we have some solution @xmath589 to eq .
( [ eqn : compactkc ] ) .
let us focus on a particular point , @xmath7 , in the base manifold and consider a curve @xmath149 joining the point @xmath590 to some nearby point @xmath591 .
at each point @xmath149 along the curve the tangent to the curve can be expressed as @xmath592 for some choice of algebra element @xmath593 , this can be viewed as simply the expansion of the tangent vector in the basis @xmath459 .
now , our solution @xmath589 to eq .
( [ eqn : compactkc ] ) is a solution for all choices of @xmath574 at all points , and thus in particular the choice @xmath593 at the point @xmath149 . abbreviating @xmath594 and @xmath595 eq .
( [ eqn : compactkc ] ) becomes , for this specific choice , @xmath596 which should then be satisfied for all @xmath42 along the curve . now , eq . ( [ eqn : diffkc ] ) is a linear first order differential equation .
thus , given the initial conditions , @xmath597 , the solution @xmath598 is uniquely determined for @xmath599 .
in particular @xmath600 is uniquely determined .
in fact , since the curve @xmath97 and the point @xmath601 are arbitrary we only need to specify @xmath589 at one single point in the base manifold from which @xmath589 will be uniquely determined for all other points .
thus , to show that all solutions to eq .
( [ eqn : compactkc ] ) can be expressed in the form @xmath586 for some algebra element @xmath41 it is sufficient to show that at a single point @xmath7 an arbitrary @xmath589 can be expressed as @xmath586 for some @xmath41 .
so let us consider a solution @xmath589 at the point @xmath7 composed of some supervector @xmath602 and algebra element @xmath603 .
first note that it is always possible to choose an algebra element @xmath34 such that @xmath604 for instance it is straightforward to show that the choice @xmath605l(p)^{-1}$ ] satisfies this equation .
however , this choice of @xmath41 is not unique , there is a freedom in the choice of @xmath41 under which @xmath305 at the point @xmath7 remains unchanged .
this can be seen in the following way .
let @xmath606 be an arbitrary element of @xmath63 , then @xmath607 from which we immediately deduce @xmath608 therefore , after choosing the algebra element @xmath41 so that at @xmath7 we have @xmath609 we still have the freedom to change @xmath610 , and under such a transformation the @xmath3-compensator @xmath611 at @xmath7 can be changed arbitrarily .
thus as well as choosing @xmath41 so that eq .
( [ eqn : choiceofavector ] ) is satisfied we may simultaneously choose @xmath41 such that @xmath612 this concludes the proof .
in this section we will apply the concepts discussed in the previous sections to the well known case of flat superspace .
we start with the super poincar group @xmath613 and its subgroup of lorentz transformations @xmath3 .
flat superspace is defined to be the coset space @xmath614 .
the non - zero commutators of the super poincar algebra , @xmath615 , are @xmath616 & = \eta_{ad}m_{bc } + \eta_{bc}m_{ad } - \eta_{ac}m_{bd } - \eta_{bd}m_{ac } \label{eqn : mmcommutator } \\ [ m_{ab},p_c ] & = \eta_{cb}p_a -\eta_{ca}p_b\label{eqn : mpcommutator}\\ [ m_{ab},q_\alpha ] & = - ( \sigma_{ab})_{\alpha}{}^\beta q_\beta \label{eqn : mqcommutator}\\ [ q_\alpha , q_\beta ] & = 2k(\gamma^a c^{-1})_{\alpha\beta}p_a \label{eqn : qqcommutator}.\end{aligned}\ ] ] here the @xmath617 are the dirac gamma matrices for the flat metric @xmath618 , @xmath619 $ ] , @xmath620 is the charge conjugation matrix , and @xmath621 is a phase factor . the indices may be grouped as @xmath622 and the antisymmetric pair @xmath623 $ ] .
we will distinguish between tangent space indices @xmath622 and coordinate indices @xmath624 , however both sets range over the same values . comparing eqs .
( [ eqn : mmcommutator][eqn : qqcommutator ] ) to eqs .
( [ eqn : algebra1][eqn : algebra3 ] ) we have that the even generators @xmath625 generate the lorentz subgroup and play the role of the @xmath67 whereas the even generators @xmath626 generating translations and the odd generators @xmath627 generating supersymmetry transformations play the role of the @xmath69 .
we see that , further to the reductive property , @xmath64 forms a nilpotent subalgebra of @xmath23 .
we have @xmath628 \subseteq \mathfrak{k } \\ \label{eqn : kkk0 } [ \mathfrak{k},[\mathfrak{k},\mathfrak{k}]]=0.\end{gathered}\ ] ] in the expansion of a general element of the super poincar algebra , @xmath629 , it is possible to restrict the @xmath630 to be _ ordinary _ real numbers .
this is a result of the reductive property of the super poincar algebra and the following : the @xmath67 are all even , the structure constants @xmath631 are ordinary real numbers ( i.e. @xmath3 is conventional @xcite ) and the coset space is flat , i.e.the structure constants @xmath632 vanish , cf . eq . ( [ eqn : trcomponents ] ) .
while such a choice for the super poincar algebra is not necessary it does allow one to deal simply with the ordinary lorentz group . as a consequence of the reductive property
any element @xmath633 can be written as @xmath634 for some @xmath635 and @xmath636 @xcite .
further , using eq .
( [ eqn : kkk ] ) , one can show that @xmath635 and @xmath636 are uniquely determined by @xmath637 .
it follows that the principal bundle is trivial , admitting a global section @xmath638 where @xmath639 are uniquely determined in terms of @xmath7 and thus can be used as the coordinates of the point @xmath7 .
this section is horizontal and can be thought of as a special choice of gauge .
let us calculate the action of an isometry on these coordinates .
consider left multiplication by @xmath640 .
for @xmath641 we can use the baker - campbell - hausdorff formula , which combined with eq .
( [ eqn : kkk0 ] ) gives @xmath642}.\ ] ] from eq .
( [ eqn : kkk ] ) we see that under this transformation we do not leave the section @xmath180 .
we thus find @xmath643 for the algebra element
@xmath644 we have @xmath645 where @xmath646 is the coadjoint representation of @xmath647 , see eq .
( [ eqn : coadjoint ] ) .
this gives @xmath648 as in this case the normalizer of the lorentz subgroup @xmath649 , see section [ sec : isometries ] , is simply @xmath3 we may determine all killing supervectors by considering the infinitesimal versions of these transformations .
we find @xmath650 it is standard to refer to these vectors as the differential operator representation of the super poincar algebra .
note , however , that due to eq .
( [ eqn : algebrapiflats ] ) the algebra will have an extra minus sign compared to @xmath651 .
a similar analysis for right multiplication leads to an expression for the vectors @xmath652 , i.e. the frame .
we find @xmath653 the coframe and the connection may be calculated from the pullback of the maurer - cartan form as in eq .
( [ eqn : theequation ] ) .
we have @xmath654 \\ & = { \mathrm{d}}x^m ( \delta_m{}^a-\frac{1}{2}x^nf_{nm}{}^a)k_a.\end{aligned}\ ] ] we may then read off the coframe and connection @xmath655 as @xmath656 we see from eq .
( [ eqn : ddef ] ) that @xmath657 .
this explains how as is usually stated in the literature in flat superspace the covariant derivative is obtained directly in terms of right multiplication on the coset space .
in general we must obviously consider the map @xmath290 of eq .
( [ eqn : defrgl ] ) . the covariant derivative @xmath658 is usually considered as the operator which ( anti)commutes with the differential operator representation of the @xmath69 , i.e. the @xmath659 , particularly for @xmath660 .
this can be seen as a special case of eq .
( [ eqn : ldcommutator ] ) since the @xmath3-compensator @xmath661 vanishes .
note that the covariant derivative will not commute with the @xmath662 as @xmath663 .
starting with the frame and connection one can construct the killing supervectors of flat superspace using the method discussed in section [ sec : killing ] , i.e. by imposing that the commutator of the generalized lie derivative with the covariant derivative be zero .
this procedure , in the four - dimensional case , is treated in @xcite .
the curvature , eq .
( [ eqn : curvaturedef ] ) , of flat superspace is clearly zero .
the only non - zero components of the torsion are given in terms of the algebra structure constants , see eq .
( [ eqn : trcomponents ] ) .
they are @xmath664 while flat superspace is a very useful example of a super coset space its geometry is relatively simple .
the same techniques we have discussed here may , however , be applied directly to more complex geometries .
a particularly well studied super coset space is the @xmath665 superspace which arises as a coset space of the super lie group @xmath666 , see for example @xcite .
a lower dimensional example of a super coset space is provided by the supersphere @xcite which is a coset space of the super lie group @xmath667 .
we have discussed in detail the geometry of super coset spaces with the focus on how the geometric structures of the coset space @xmath0 are inherited from @xmath1 .
while the concepts and methods presented in this paper apply to coset spaces in general , our main aim has been to analyze the geometry of _ super _ coset spaces and their isometries . as such one important aspect of our work was to review and clarify the notion of killing supervectors in the context of super coset spaces . due to the fact that the notion of supermetric is not physically relevant for the construction of superspace the standard definition of isometries in terms of the metric
can not be applied and must be given in terms of the supergeometry the frame and connection .
although the definition of killing supervectors we give is derived from the understanding of the geometry of coset spaces it clearly extends to more general situations .
the authors would like to thank professor n. s. manton for helpful comments on the manuscript .
we define a super @xmath201-form @xmath202 on a supermanifold @xmath668 at the point @xmath7 to be a mapping from @xmath201 copies of the tangent supervector space to @xmath81 , the real supernumbers , i.e. @xmath669 the target space can be generalized to any vector space with a `` multiplication '' , e.g. a super lie algebra .
while in this paper we write the supervectors on which a form acts on the right , its properties are more conveniently represented with the vectors on the left , we define @xmath670 we then require the following properties to be satisfied given a @xmath7-form @xmath202 and a @xmath601-form @xmath673 we define the exterior ( wedge ) product @xmath674 by its action on a set of @xmath675 pure supervectors as @xmath676 here @xmath677 is a permutation on @xmath675 elements .
the quantity @xmath678 is defined as @xmath679 where the @xmath680 , @xmath681 , are pure supernumbers .
it is possible to show that the definition eq .
( [ eqn : wedgedef ] ) does indeed define a @xmath682-form .
further , if @xmath202 and @xmath673 are pure forms we have @xmath683 where the @xmath202 and @xmath673 occurring in the exponent denote the parities of @xmath202 and @xmath673 , respectively . in the case
when the target space in eq .
( [ eqn : formdef ] ) is generalized to a super lie algebra we have an _ algebra valued form_. the product used in the definition eq .
( [ eqn : wedgedef ] ) must be replaced by the lie algebra bracket , to indicate this we denote the wedge product instead by @xmath684 $ ] .
the symmetry of this wedge product has an additional minus sign @xmath685= -(-1)^{\phi\psi+pq}[\psi,\phi].\ ] ] if we work in a matrix representation of the algebra we could instead use matrix multiplication as the product and define @xmath674 . while this latter wedge product does not in general result in an algebra valued form we do however have the relation @xmath685=\phi\wedge\psi - ( -1)^{\phi\psi+pq}\psi\wedge\phi.\ ] ] in particular @xmath686 is algebra valued .
let us suppose we have a basis of one - forms @xmath137 , @xmath690 .
our conventions for expanding the form @xmath202 in this basis are , cf . eq . ( [ eqn : covariantexp ] ) @xmath691 here we have used the parity function , defined as @xmath692 where @xmath693 and @xmath694 represent the parities of the indices .
this function could in fact take as arguments any set of objects with parity , for example see eq .
( [ eqn : formvectorcomponents ] ) below . note that this function is clearly linear in both arguments .
further , @xmath695 is just the sum over all non - equal pairs of indices and is invariant under any index permutation . using this it is possible to show that the components of @xmath202 are given by @xmath696
we can then also show that @xmath697 consider two curves @xmath698\to g$ ] in the group which both project down to the same curve @xmath96\to g / h$ ] in the base , i.e. @xmath699 , for @xmath700 .
clearly then we have @xmath701 for some function @xmath150 .
let @xmath702 , @xmath703 denote the tangent vectors to the curves in the group , and @xmath33 the tangent vector to the curve in the base .
working in a matrix representation we thus have @xmath704 now consider @xmath705 & = x_1\big|_{\gamma_1(0 ) } [ f \circ r_{h(0 ) } ] \\ \nonumber & = { \frac{\mathrm{d}}{\mathrm{d}t } } f \circ r_{h(0 ) } \circ \gamma_1(t ) \big|_{t=0 } \\
\nonumber & = { \frac{\mathrm{d}}{\mathrm{d}t}}f(\gamma_1(t)h(0))\big|_{t=0},\end{aligned}\ ] ] from which we deduce @xmath706 also we have @xmath707 thus if we use both eqs .
( [ eqn : firstterm],[eqn : secondterm ] ) in eq .
( [ eqn : bothterms ] ) we find @xmath708 note that the point @xmath709 is not special , and in general we have @xmath710 eq .
( [ eqn : xmakehorizontal ] ) follows immediately from this result by choosing @xmath711 and @xmath712 , whereas eq .
( [ eqn : xchangesection ] ) follows by choosing @xmath711 and @xmath713 . n. alonso - alberca , e. lozano - tellechea , and t. ortn , `` geometric construction of killing spinors and supersymmetry algebras in homogeneous spacetimes , '' _ class .
* 19 * ( 2002 ) 60096024 , http://www.arxiv.org/abs/hep-th/0208158[hep-th/0208158 ] .
l. andrianopoli , s. ferrara , m. a. lle , and o. maci , `` integration of massive states as contractions of non - linear @xmath677-models , '' _ j. math .
_ * 46 * ( 2005 ) 072307 , http://www.arxiv.org/abs/hep-th/0503196[hep-th/0503196 ] .
p. claus , j. rahmfeld , h. robins , j. tannenhauser , and y. zunger , `` isometries in anti - de sitter and conformal superspaces , '' _ jhep _ * 0007 * ( 2000 ) 047 , http://www.arxiv.org/abs/hep-th/0007099[hep-th/0007099 ] . | super coset spaces play an important role in the formulation of supersymmetric theories .
the aim of this paper is to review and discuss the geometry of super coset spaces with particular focus on the way the geometrical structures of the super coset space @xmath0 are inherited from the super lie group @xmath1 .
the isometries of the super coset space are discussed and a definition of killing supervectors the supervectors associated with infinitesimal isometries is given that can be easily extended to spaces other than coset spaces .
pacs numbers : 02.40.-k , 11.30.pb , 12.60.jv |
forty patients ( 20 men and 20 women ) with type 1 diabetes and 40 patients ( 20 men and 20 women ) with type 2 diabetes were recruited among the patients followed in our department .
patients with arterial hypertension , renal insufficiency , or cvd or taking medications interfering with vascular reactivity ( including any type of antihypertensive agents ) were excluded from the study .
all patients with type 1 diabetes received intensified insulin therapy with multiple daily insulin injections ( n = 36 ) or continuous subcutaneous insulin infusion via a portable pump ( n = 4 ) .
patients with type 2 diabetes received various types of oral glucose - lowering therapies ( metformin alone , sulfonylurea alone , or metformin - sulfonylurea combination ) ( n = 25 ) or insulin alone ( n = 5 ) or combined with metformin ( n = 10 ) .
two groups of healthy subjects were used as control subjects and matched for bmi with either type 1 diabetic patients or type 2 diabetic patients ( table 1 ) .
characteristics of middle - aged diabetic patients with type 1 diabetes , patients with type 2 diabetes , nondiabetic lean control subjects , and nondiabetic overweight / obese control subjects and average values recorded during the whole 3-min squatting test data are means sd .
lc , nondiabetic lean control subjects ; na , not applicable ; oc , nondiabetic overweight / obese control subjects ; t1 dm , patients with type 1 diabetes , t2 dm , patients with type 2 diabetes . the squatting test ( successively 1 min standing , 1 min squatting , and 1 min standing ) is an original active orthostatic maneuver that leads to the most important and fast variations of the hydrostatic level with posture ( 9 ) .
squatting produces a prompt increase in cardiac output and arterial blood pressure , essentially attributed to augmented venous return from compression of leg veins .
these changes result in a significant increase in mean arterial blood pressure and pulse pressure ( 7,8 ) , which is accompanied by an immediate decrease in heart rate and forearm vascular resistance , probably due to activation of cardiopulmonary and arterial baroreflexes , implicating the autonomic nervous system .
later on , the active transition from squatting to standing results in a profound initial blood pressure decrease inducing a reflex tachycardia , which can be used to detect diabetic cardiac autonomic neuropathy ( can ) ( 10,11 ) and assess baroreflex sensitivity ( 12 ) .
changes in systolic blood pressure ( sbp ) , diastolic blood pressure ( dbp ) , and heart rate were measured continuously with a finapres instrument ( ohmeda ) that allows careful study of cardiovascular reflexes , especially during an orthostatic maneuver ( 13 ) .
the finapres is based on servoplethysmomanometry , using the volume clamp technique at the finger level .
a good concordance was reported between finapres blood pressure measurements and direct intra - arterial measurements ( 13 ) .
pulse pressure , i.e. , sbp minus dbp , was automatically calculated throughout the test .
mean arterial blood pressure ( mbp ) was calculated by the formula ( sbp + 2 dbp)/3 . to quantify the relative magnitude of the pulsatile to mean artery pressure ( pulsatility index ) , we normalized the pulse pressure to the mbp and referred to this value as fractional pulse pressure ( 14 )
. pulsatile stress was defined as the double product of pulse pressure and heart rate ( pphr ) ) ; it has been shown to be largely regulated by arterial stiffness and by sympathetic nerve activity and to be associated with a higher risk of ( micro)albuminuria ( 15 ) .
we also calculated the sbphr double product , an index of cardiac load that has been shown to be associated with an increased cvd risk ( 16 ) .
for each variable or parameter , mean levels were calculated for each subject during the whole period of the test , during the initial standing position , and during the squatting position , after exclusion of the initial transition phase , as described previously ( 7,8 ) . during the transition from squatting to standing
, there is an abrupt drop in blood pressure associated with a reflex tachycardia , which is followed by a rapid return to baseline values of both parameters ( blood pressure increase and heart rate decrease ) .
the mirror changes in heart rate and sbp allow the calculation of a baroreflex gain by plotting the pulse intervals ( r - r ) against sbp values , and the slope of this relation represents the baroreflex sensitivity ( 17 ) .
we also calculated both a vagal index ( ratio between the baseline cardiac r - r interval and the longest r - r interval in the first 15 s of squatting [ sqtv ] ) and a sympathetic index ( ratio between the baseline cardiac r - r interval and the shortest r - r interval in the first 1020 s of standing after squatting [ sqts ] ) , as described previously ( 10,11 ) .
these indexes , based on heart rate reduction during squatting and reflex tachycardia during standing , were considered as markers of can : a higher sqtv value indicates a parasympathetic neuropathy , whereas a lower sqts is an indicator of sympathetic neuropathy ( 1012 ) .
concomitant a1c levels ( normal values 46% ) were measured to assess recent blood glucose control in diabetic patients ; for each patient , the corresponding a1c mean level corresponded to the average of one to three measurements .
lipid profiles were also collected in diabetic patients and the prevalence of the metabolic syndrome ( national cholesterol education program adult treatment panel iii criteria ) was calculated in patients with type 1 diabetes and in patients with type 2 diabetes . the required sample size to have an 80% chance of detecting as significant ( at the two - sided 5% level ) 10 mmhg difference in pulse pressure between two different subgroups , with an assumed sd of pulse pressure of 14 mmhg , was 32 individuals . a difference of 10 mmhg
was chosen as clinically significant because it has been shown to be associated with increased cardiovascular mortality in type 2 diabetes ( 1 ) and total mortality in the large eurodiab cohort of patients with type 1 diabetes ( 5 ) .
the relationship between two variables , i.e. , between pulsatile stress and baroreflex gain as a marker of can , was assessed with the spearman correlation coefficient .
the squatting test ( successively 1 min standing , 1 min squatting , and 1 min standing ) is an original active orthostatic maneuver that leads to the most important and fast variations of the hydrostatic level with posture ( 9 ) .
squatting produces a prompt increase in cardiac output and arterial blood pressure , essentially attributed to augmented venous return from compression of leg veins .
these changes result in a significant increase in mean arterial blood pressure and pulse pressure ( 7,8 ) , which is accompanied by an immediate decrease in heart rate and forearm vascular resistance , probably due to activation of cardiopulmonary and arterial baroreflexes , implicating the autonomic nervous system .
later on , the active transition from squatting to standing results in a profound initial blood pressure decrease inducing a reflex tachycardia , which can be used to detect diabetic cardiac autonomic neuropathy ( can ) ( 10,11 ) and assess baroreflex sensitivity ( 12 ) .
changes in systolic blood pressure ( sbp ) , diastolic blood pressure ( dbp ) , and heart rate were measured continuously with a finapres instrument ( ohmeda ) that allows careful study of cardiovascular reflexes , especially during an orthostatic maneuver ( 13 ) .
the finapres is based on servoplethysmomanometry , using the volume clamp technique at the finger level .
a good concordance was reported between finapres blood pressure measurements and direct intra - arterial measurements ( 13 ) .
pulse pressure , i.e. , sbp minus dbp , was automatically calculated throughout the test .
mean arterial blood pressure ( mbp ) was calculated by the formula ( sbp + 2 dbp)/3 . to quantify the relative magnitude of the pulsatile to mean artery pressure ( pulsatility index ) , we normalized the pulse pressure to the mbp and referred to this value as fractional pulse pressure ( 14 )
. pulsatile stress was defined as the double product of pulse pressure and heart rate ( pphr ) ) ; it has been shown to be largely regulated by arterial stiffness and by sympathetic nerve activity and to be associated with a higher risk of ( micro)albuminuria ( 15 ) .
we also calculated the sbphr double product , an index of cardiac load that has been shown to be associated with an increased cvd risk ( 16 ) . for each variable or parameter ,
mean levels were calculated for each subject during the whole period of the test , during the initial standing position , and during the squatting position , after exclusion of the initial transition phase , as described previously ( 7,8 ) . during the transition from squatting to standing , there is an abrupt drop in blood pressure associated with a reflex tachycardia , which is followed by a rapid return to baseline values of both parameters ( blood pressure increase and heart rate decrease ) .
the mirror changes in heart rate and sbp allow the calculation of a baroreflex gain by plotting the pulse intervals ( r - r ) against sbp values , and the slope of this relation represents the baroreflex sensitivity ( 17 ) .
we also calculated both a vagal index ( ratio between the baseline cardiac r - r interval and the longest r - r interval in the first 15 s of squatting [ sqtv ] ) and a sympathetic index ( ratio between the baseline cardiac r - r interval and the shortest r - r interval in the first 1020 s of standing after squatting [ sqts ] ) , as described previously ( 10,11 ) .
these indexes , based on heart rate reduction during squatting and reflex tachycardia during standing , were considered as markers of can : a higher sqtv value indicates a parasympathetic neuropathy , whereas a lower sqts is an indicator of sympathetic neuropathy ( 1012 ) .
concomitant a1c levels ( normal values 46% ) were measured to assess recent blood glucose control in diabetic patients ; for each patient , the corresponding a1c mean level corresponded to the average of one to three measurements .
lipid profiles were also collected in diabetic patients and the prevalence of the metabolic syndrome ( national cholesterol education program adult treatment panel iii criteria ) was calculated in patients with type 1 diabetes and in patients with type 2 diabetes .
the required sample size to have an 80% chance of detecting as significant ( at the two - sided 5% level ) 10 mmhg difference in pulse pressure between two different subgroups , with an assumed sd of pulse pressure of 14 mmhg , was 32 individuals .
a difference of 10 mmhg was chosen as clinically significant because it has been shown to be associated with increased cardiovascular mortality in type 2 diabetes ( 1 ) and total mortality in the large eurodiab cohort of patients with type 1 diabetes ( 5 ) .
the relationship between two variables , i.e. , between pulsatile stress and baroreflex gain as a marker of can , was assessed with the spearman correlation coefficient .
compared with control subjects , patients with type 1 diabetes had similar mbp but were characterized throughout the test by significantly higher pulse pressure , heart rate , pulse pressure / mbp , pphr , and sbphr levels ( fig .
when squatting was compared with the initial standing position , a trend for higher increases in pulse pressure , pp / mbp , and pphr was observed in patients with type 1 diabetes than in control subjects , with a significantly higher increase in sbphr ( table 2 ) .
the baroreflex gain calculated during the transition from squatting to standing was markedly decreased in patients with type 1 diabetes compared with that in control subjects .
sqtv and sqts indexes were also significantly different in patients with type 1 diabetes compared with those in lean control subjects ( table 2 ) .
there was a significant inverse correlation between pulsatile stress ( pphr ) and baroreflex gain in patients with type 1 diabetes ( r = 0.383 ; p = 0.023 ) but not in lean control subjects ( r = 0.178 ; ns ) .
changes in mbp , pulse pressure ( pp ) , and heart rate ( hr ) during a posture test ( 1 min standing , 1 min squatting [ gray zone ] , 1 min standing ) . a : 40 patients with type 1 diabetes ( ) versus 40 nondiabetic ( ) subjects , matched for age , sex , and bmi .
b : 40 patients with type 2 diabetes ( ) versus 40 nondiabetic ( ) subjects matched for age , sex , and bmi .
c : 40 patients with type 1 diabetes ( ) versus 40 patients with type 2 diabetes ( ) subjects , matched for age and sex .
changes occurring during the transition from the initial standing position to the squatting position in middle - aged diabetic patients with type 1 diabetes , patients with type 2 diabetes , nondiabetic lean control subjects , and nondiabetic overweight / obese control subjects data are means sd .
mean values of baroreflex gain as well as sqtv and sqts indices of cardiac autonomic neuropathy are also presented for the four groups .
lc , nondiabetic lean control subjects ; oc , nondiabetic overweight / obese control subjects ; t1 dm , patients with type 1 diabetes ; t2 dm , patients with type 2 diabetes . compared with overweight / obese nondiabetic control subjects , patients with type 2 diabetes had similar mbp (
hypertension was considered as an exclusion criterion in the present study ) . however , they showed higher pulse pressure , heart rate , pulse pressure - to - mbp ratio , pphr , and sbphr levels throughout the test ( fig . 1b , table 1 ) .
increases in pulse pressure , pulse pressure - to - mbp ratio , pphr , and sbphr when moving from standing to squatting were not significantly different in patients with type 2 diabetes and in overweight / obese nondiabetic control subjects ( table 2 ) .
the baroreflex gain was significantly decreased in patients with type 2 diabetes compared with that in control subjects .
the sqts index ( reflecting postsquatting tachycardia ) but not the sqtv index ( a marker of bradycardia during squatting ) was significantly lower in patients with type 2 diabetes than in overweight / obese nondiabetic control subjects ( table 2 ) . there was a highly significant inverse correlation between pulsatile stress and baroreflex gain in patients with type 2 diabetes ( r = 0.719 ; p = 0.0001 ) but not in overweight / obese control subjects ( r = 0.272 ; ns ) .
no significant differences in pulsatile markers and can indexes were noticed between the patients with type 2 diabetes treated with insulin and those not treated with insulin . on average , mbp , pulse pressure , heart rate , pulse pressure - to - mbp ratio , pphr , and sbphr levels were comparable in middle - aged patients with type 1 and type 2 diabetes ( fig . 1c , table 1 ) .
the transition from standing to squatting resulted in similar increases in mbp , pulse pressure , pulse pressure - to - mbp ratio , pphr , and sbphr in the two groups of diabetic patients ( table 2 ) .
careful analysis of the two pulse pressure curves showed different kinetics in pulse pressure increases , with a second phase increase in pulse pressure in patients with type 1 diabetes that was not observed in patients with type 2 diabetes ; however , the between - group difference during the second part of squatting did not reach statistical significance ( fig .
accordingly , sqtv and sqts indexes were not significantly different between the two diabetic groups ( table 2 ) .
patients with type 1 diabetes had a much longer known disease duration ( 23 vs. 8 years ; p <
0.0001 ) but a much lower prevalence of metabolic syndrome ( 3% vs. 42% ; p < 0.01 ) than patients with type 2 diabetes . on average , mbp , pulse pressure , heart rate , pulse pressure - to - mbp ratio , pphr , and sbphr levels were comparable in obese and lean nondiabetic individuals in the present study ( table 1 ) .
the postural change from standing to squatting resulted in similar increases in mbp , pulse pressure , pulse pressure - to - mbp ratio , and pphr in overweight / obese and lean subjects , with only a trend for a higher increase in sbphr ( + 963 1,178 vs. + 601 698 mmhg min ; p = 0.0991 ) in presence of obesity ( table 2 ) .
the baroreflex gain was significantly lower in overweight / obese subjects than in lean individuals ( 2.97 2.18 vs. 4.11 2.26 mmhg min ; p = 0.0332 ) , even in absence of diabetes .
the sqtv index was higher in obese subjects than in lean control subjects ( p = 0.0011 ) , whereas the sqts index was almost similar in the two nondiabetic groups ( table 2 ) .
compared with control subjects , patients with type 1 diabetes had similar mbp but were characterized throughout the test by significantly higher pulse pressure , heart rate , pulse pressure / mbp , pphr , and sbphr levels ( fig .
when squatting was compared with the initial standing position , a trend for higher increases in pulse pressure , pp / mbp , and pphr was observed in patients with type 1 diabetes than in control subjects , with a significantly higher increase in sbphr ( table 2 ) .
the baroreflex gain calculated during the transition from squatting to standing was markedly decreased in patients with type 1 diabetes compared with that in control subjects .
sqtv and sqts indexes were also significantly different in patients with type 1 diabetes compared with those in lean control subjects ( table 2 ) .
there was a significant inverse correlation between pulsatile stress ( pphr ) and baroreflex gain in patients with type 1 diabetes ( r = 0.383 ; p = 0.023 ) but not in lean control subjects ( r = 0.178 ; ns ) .
changes in mbp , pulse pressure ( pp ) , and heart rate ( hr ) during a posture test ( 1 min standing , 1 min squatting [ gray zone ] , 1 min standing ) . a : 40 patients with type 1 diabetes ( ) versus 40 nondiabetic ( ) subjects , matched for age , sex , and bmi .
b : 40 patients with type 2 diabetes ( ) versus 40 nondiabetic ( ) subjects matched for age , sex , and bmi .
c : 40 patients with type 1 diabetes ( ) versus 40 patients with type 2 diabetes ( ) subjects , matched for age and sex .
changes occurring during the transition from the initial standing position to the squatting position in middle - aged diabetic patients with type 1 diabetes , patients with type 2 diabetes , nondiabetic lean control subjects , and nondiabetic overweight / obese control subjects data are means sd .
mean values of baroreflex gain as well as sqtv and sqts indices of cardiac autonomic neuropathy are also presented for the four groups .
lc , nondiabetic lean control subjects ; oc , nondiabetic overweight / obese control subjects ; t1 dm , patients with type 1 diabetes ; t2 dm , patients with type 2 diabetes .
compared with overweight / obese nondiabetic control subjects , patients with type 2 diabetes had similar mbp ( hypertension was considered as an exclusion criterion in the present study ) .
however , they showed higher pulse pressure , heart rate , pulse pressure - to - mbp ratio , pphr , and sbphr levels throughout the test ( fig . 1b , table 1 ) .
increases in pulse pressure , pulse pressure - to - mbp ratio , pphr , and sbphr when moving from standing to squatting were not significantly different in patients with type 2 diabetes and in overweight / obese nondiabetic control subjects ( table 2 ) .
the baroreflex gain was significantly decreased in patients with type 2 diabetes compared with that in control subjects . the sqts index ( reflecting postsquatting tachycardia ) but not the sqtv index ( a marker of bradycardia during squatting ) was significantly lower in patients with type 2 diabetes than in overweight / obese nondiabetic control subjects ( table 2 ) . there was a highly significant inverse correlation between pulsatile stress and baroreflex gain in patients with type 2 diabetes ( r = 0.719 ; p = 0.0001 ) but not in overweight / obese control subjects ( r = 0.272 ; ns ) .
no significant differences in pulsatile markers and can indexes were noticed between the patients with type 2 diabetes treated with insulin and those not treated with insulin .
on average , mbp , pulse pressure , heart rate , pulse pressure - to - mbp ratio , pphr , and sbphr levels were comparable in middle - aged patients with type 1 and type 2 diabetes ( fig . 1c , table 1 ) .
the transition from standing to squatting resulted in similar increases in mbp , pulse pressure , pulse pressure - to - mbp ratio , pphr , and sbphr in the two groups of diabetic patients ( table 2 ) .
careful analysis of the two pulse pressure curves showed different kinetics in pulse pressure increases , with a second phase increase in pulse pressure in patients with type 1 diabetes that was not observed in patients with type 2 diabetes ; however , the between - group difference during the second part of squatting did not reach statistical significance ( fig .
accordingly , sqtv and sqts indexes were not significantly different between the two diabetic groups ( table 2 ) .
patients with type 1 diabetes had a much longer known disease duration ( 23 vs. 8 years ; p < 0.0001 ) but a much lower prevalence of metabolic syndrome ( 3% vs. 42% ; p < 0.01 ) than patients with type 2 diabetes .
on average , mbp , pulse pressure , heart rate , pulse pressure - to - mbp ratio , pphr , and sbphr levels were comparable in obese and lean nondiabetic individuals in the present study ( table 1 ) .
the postural change from standing to squatting resulted in similar increases in mbp , pulse pressure , pulse pressure - to - mbp ratio , and pphr in overweight / obese and lean subjects , with only a trend for a higher increase in sbphr ( + 963 1,178 vs. + 601 698 mmhg min ; p = 0.0991 ) in presence of obesity ( table 2 ) .
the baroreflex gain was significantly lower in overweight / obese subjects than in lean individuals ( 2.97 2.18 vs. 4.11 2.26 mmhg min ; p = 0.0332 ) , even in absence of diabetes .
the sqtv index was higher in obese subjects than in lean control subjects ( p = 0.0011 ) , whereas the sqts index was almost similar in the two nondiabetic groups ( table 2 ) .
the main findings of the present study are 1 ) higher pulse pressure , pulse pressure - to - mbp ratio , pphr , and sbphr levels in middle - aged patients with type 1 diabetes compared with those in lean control subjects , in agreement with higher pulsatile stress and cardiac workload in patients with long - standing type 1 diabetes , 2 ) similarly , higher pulse pressure , pulse pressure - to - mbp ratio , pphr , and sbphr levels in middle - aged nonhypertensive patients with type 2 diabetes compared with those in overweight / obese nondiabetic control subjects , 3 ) the absence of significant differences in pulse pressure , pulsatile index , pulsatile stress , and double product between patients with type 1 diabetes and with type 2 diabetes matched for age ( 50 years on average ) ; and 4 ) indexes of can as shown by lower baroreflex gain and altered sqt indexes during squatting in both patients with type 1 diabetes and type 2 diabetes compared with those in nondiabetic control subjects .
therefore , middle - aged patients with type 1 diabetes or with type 2 diabetes are exposed to comparable pulsatile stress , a known cardiovascular and renal risk marker ( 15,15,16 ) . in patients with type 1 diabetes ,
the negative influence of a much longer diabetes duration ( 23 years on average in the present study ) might be at least partially compensated for by the positive influence of lower bmi , less insulin resistance , and a much lower prevalence of metabolic syndrome compared with those for patients with type 2 diabetes .
on the contrary , middle - aged patients with type 2 diabetes are exposed to high pulsatile stress despite a shorter known duration of diabetes ( 8 years on average in our population ) , presumably because of the presence of other concomitant cardiovascular risk factors ( even if hypertension were excluded in the present study ) , as shown by a much higher prevalence of metabolic syndrome compared with that for patients with type 1 diabetes .
the observation of higher pulse pressure levels in patients with type 1 diabetes compared with control subjects in the age range 4060 years is in agreement with previous studies from our group , demonstrating an earlier pulse pressure increase with age in this population ( 7,8 ) and with the observational data of the large cross - sectional , case - control finndiane study ( 3 ) . because pulse pressure is considered an indirect marker of arterial stiffness , these higher pulse pressure results are in agreement with accelerated vascular aging in the population with type 1 diabetes ( 6 ) , especially patients with chronic poor glucose control ( 18 ) . in the finndiane study ,
the ambient level of glucose was not associated with increased pulse pressure , but the time of exposure to hyperglycemia seemed to play a fundamental role in the process of premature arterial stiffening in patients with type 1 diabetes ( 3 ) . in the eurodiab prospective complications study , pulse pressure
was significantly associated with all - cause mortality and a mean 12 mmhg higher pulse pressure was observed in patients with type 1 diabetes who died compared with that of those who survived ( 5 ) . decreased baroreflex gain
was observed in our patients with type 1 diabetes , reflecting the presence of can after > 20 years of diabetes ( 19 ) .
this result was confirmed by altered sqts and sqtv indexes during the squatting test , markers of parasympathetic and sympathetic dysfunction , respectively ( 10 ) . can exposes diabetic patients to an increased mortality risk ( 19 ) .
there may be some connection between pulse pressure and can ( 8) , between aortic stiffness and can ( 20 ) , and between arterial stiffness , cardiovagal baroreflex sensitivity , and postural blood pressure changes ( 21 ) .
increased sbp was identified as a factor associated with an increased risk of developing can in the cohort of patients with type 1 diabetes of the eurodiab prospective complications study ( 22 ) .
the pathophysiological mechanism linking can to arterial stiffness in patients with type 1 diabetes remains unknown , but this association persisted after adjustment for potential confounders such as baseline a1c , hdl cholesterol , and smoking history ( 23 ) . in the present study , we found a significant relationship between pulsatile stress and baroreflex gain as a marker of can in patients with type 1 diabetes . in patients with type 2 diabetes , markers of can
are also present ( 11 ) , although less marked than in patients with prolonged type 1 diabetes ( 7 ) .
the relationship between pulse pressure and can is less well known in patients with type 2 diabetes even if associations between autonomic neuropathy , vascular dysfunction , and hyperinsulinemia have been demonstrated ( 24 ) .
interestingly , a remarkable significant inverse correlation was noted between pulsatile stress and baroreflex gain in the group of patients with type 2 diabetes in our study .
the stiffness of the carotid arteries and the aorta , where the arterial baroreceptors are located , may affect the stretch - sensitive receptors and hence baroreflex sensitivity .
in addition to structural vascular changes , functional mechanisms associated with endothelial dysfunction may also contribute to the impairment of baroreflex sensitivity associated with arterial stiffness ( 21 ) .
patients with type 2 diabetes also showed increased pulse pressure , pulsatility index , and pulsatile stress compared with those for overweight / obese nondiabetic individuals matched for bmi , age , and sex .
this result was observed despite the absence of hypertension and a much shorter duration of diabetes compared with those in the population with type 1 diabetes analyzed in the present study .
it is well known , however , that type 2 diabetes remains silent during an average of 10 years before diagnosis and initiation of treatment in most cases .
thus , selected patients may have a longer duration of type 2 diabetes than the average 8-year known duration noted in the present population .
to avoid the potential bias of hypertension and the interferences of antihypertensive agents , we deliberately selected type 2 diabetic patients without hypertension . despite normal mbp , middle - aged patients with type 2 diabetes had higher pulse pressure and pulsatile stress and higher sbphr , two cvd risk markers ( 16 ) . increased pulse pressure levels have been repeatedly demonstrated in large longitudinal studies in patients with type 2 diabetes and shown to be associated with a higher incidence of cardiovascular events ( 1,2 ) . some limitations of the present study should be discussed .
several studies have demonstrated that absolute brachial and finger pulse pressure measurements are not identical with larger differences in sbp . however , the differences were generally small and not considered of clinical relevance ( 13 ) .
furthermore , some studies have shown a good concordance between periphery ( finger , as in the present study ) and central ( aortic , now recognized as the most important risk factor ) blood pressure measurements ( 25 ) .
nevertheless , pulse pressure measured at the finger site may not necessarily reflect central pulse pressure because of the amplification phenomenon .
second , glucose control of patients with type 1 diabetes evaluated in the present study was far from optimal , despite intensified insulin therapy . therefore , our results could not necessarily be extrapolated to patients with near normoglycemia for many years because chronic hyperglycemia seems to play a major role in accelerating arterial stiffness ( 18 ) .
third , patients with type 2 diabetes selected in the present study did not have hypertension .
therefore , the similar results in markers of pulsatile stress in middle - aged patients with type 1 and type 2 diabetes should be interpreted in this context .
we can not exclude the possibility that overweight / obese patients with type 2 diabetes and hypertension may be exposed to higher vascular stress than lean normotensive patients with type 1 diabetes at the same age .
this would certainly be the case for sbphr but may also be true for the various pulsatility markers .
fourth , very few patients had positive microalbuminuria in the two diabetic cohorts analyzed in the present study , because we excluded patients with hypertension or those taking antihypertensive agents .
therefore , we were not in a position to study the possible relationship between pulsatile stress and early renal alterations as shown in previous studies ( 15 ) . in summary ,
middle - aged patients with a long duration of type 1 diabetes have similarly increased pulsatile stress compared with age - matched patients with type 2 diabetes characterized by a shorter duration of the disease , but the presence of other vascular risk factors such as obesity and insulin resistance and no hypertension .
in addition , both diabetic groups have markers of can with a reduced baroreflex gain compared with nondiabetic control subjects .
the combination of these risk factors may contribute to increase the cvd risk in type 1 diabetic patients with a long exposure to chronic hyperglycemia in a fashion similar to that of patients with type 2 diabetes whose high cvd risk is well known . | objectivearterial pulse pressure is considered to be an independent cardiovascular risk factor .
we compared pulse pressure during an active orthostatic test in middle - aged patients with type 1 diabetes and with type 2 diabetes and corresponding nondiabetic control subjects.research design and methodsforty patients with type 1 diabetes ( mean age 50 years , diabetes duration 23 years , and bmi 23.0 kg / m2 ) were compared with 40 nonhypertensive patients with type 2 diabetes ( respectively , 50 years , 8 years , and 29.7 kg / m2 ) .
patients taking antihypertensive agents or with renal insufficiency were excluded .
all patients were evaluated with a continuous noninvasive arterial blood pressure monitoring ( finapres ) in standing ( 1 min ) , squatting ( 1 min ) , and again standing position ( 1 min ) .
patients with type 1 or type 2 diabetes were compared with two groups of 40 age- , sex- and bmi - matched healthy subjects.resultspatients with type 1 diabetes and patients with type 2 diabetes showed significantly higher pulse pressure , heart rate , and double product of pulse pressure and heart rate ( pphr ) ( type 1 : 5,263 vs. 4,121 mmhg / min , p = 0.0004 ; type 2 : 5,359 vs. 4,321 mmhg , p = 0.0023 ) levels than corresponding control subjects .
there were no significant differences between patients with type 1 diabetes and type 2 diabetes regarding pulse pressure ( 59 vs. 58 mmhg ) , heart rate ( 89 vs. 88/min ) , and pphr ( 5,263 vs. 5,359 mmhg / min).conclusionspatients with type 1 diabetes have increased levels of peripheral pp , an indirect marker of arterial stiffness , and pphr , an index of pulsatile stress , comparable to those of nonhypertensive patients with type 2 diabetes at similar mean age of 50 years . |
its overall prevalence ranges from 541% depending on population and type of measure , but most likely it is between 7% and 10% .
males are affected twice as often as females ( a 2 : 1 ratio ) .
srcs are defined as type i in the bosniak classification and are characterized by round or oval shape with a hairline - thin wall .
src is without septa or calcifications and does not enhance after contrast injection on computer tomography ( ct ) examination .
the well established indications for cyst treatment are concomitant symptoms caused by the lesion , including pain , hypertension , hemorrhage within the cyst , or cyst rupture .
it was shown that polycythemia may occur in patients with unilateral cystic disease , probably due to production of erythropoietin ( epo ) by the cyst wall .
the aim of this study was to assess src treatment outcomes in our 10 years of experience .
in addition , we analyzed the number of red blood cells in patients with and without srcs as indirect equivalents of erythropoietin concentration .
patients were treated either by laparoscopic ( n-135 ) or retroperitoneoscopic ( n=45 ) src decortication or by simple fluid aspiration under ultrasound guidance with subsequent sclerosing agent injection ( n=30 ) .
briefly , laparoscopic renal cyst decortication is conducted in a 45 degree modified flank position with the assistance of 3 trocars ( 10 mm , 10 mm , and 5 mm ) .
a 1-mm trocar for the camera is placed just lateral to the rectus at the level of the umbilicus , while the other two cameras are positioned under direct visualization . for a right - sided lesion , the 10 mm trocar for right hand
the 5-mm trocar for left hand is placed at the same line 3 finger widths caudate to the umbilicus .
after mobilization of the colon , gerota s fascia is swept out of the cyst wall .
retroperitoneoscopic approach is also conducted with 3 trocars ( 10 mm , 10 mm , and 5 mm ) .
a 2-cm skin incision is made just beneath the 12 rib at the superior lumbar triangle . with blunt finger dissection
a second 10-mm trocar is placed under laparoscopic vision along the anterior axillary line in line with the first trocar .
a third 5-mm trocar is placed a few finger widths posterior to the second trocar .
further steps are similar to those in laparoscopic approach . in patient with comorbidities , fluid aspiration under ultrasound visualization
various sclerosing agents are in use , including alcohol , tetracycline , minocycline , and povidine - iodine [ 914 ] . in our patients
we used tetracycline . on the assumption that the cyst wall produces erythropoietin , we searched for correlations between cyst burden and number of red blood cells ( rbc ) , hemoglobin ( hgb ) , hematocrit ( hct ) , and thrombocytes ( plt ) .
we considered the cyst burden as a spherical surface according to the following function ( 4r ; r - cyst radius ) . in case of multiple cysts ,
the burden was estimated in terms of surface sum of the 3 major cysts . additionally , we compared our cohort with a control group of patients treated due to benign prostate hyperplasia ( bph ) ( n=134 ) .
secondly , we assessed mean blood pressure ( map ) in patients with src before and 1 year after surgery . as a positive response , we adopted either reduction of map in patients with hypertension ( considered systolic pressure > 140 mmhg and/or diastolic pressure > 90 mmhg ) or dose reduction of antihypertensive drugs .
a reduction of cyst size of at least 50% in diameter was considered successful treatment . to exclude any influence of nutritional status or impaired glomerular filtration ( gfr ) rate on blood cell count
based on these parameters , body mass index ( bmi ) and estimated gfr ( egfr formula according to cockcroft - gault ) were calculated and presented before and after treatment ( tables 2 and 3 ) .
one hundred fifty ( 71.4% ) patients desired treatment due to discomfort or pain in the loin .
others were treated due to significantly enlarged ( > 10 cm ) src without any symptoms .
preoperatively , there were no differences between experimental and control group in terms of creatinine concentration , estimated glomerular filtration rate , and body mass index ( table 2 ) .
bmi , creatinine concentration and egfr did not change significantly after src treatment ( table 3 ) .
hgb , hct , and rbc were significantly higher in the src group than in the bph group ( table 2 ) .
the cyst burden was positively correlated with preoperative hct ( r=0.69 ; p<0.01 ) , rbc ( r=0.42 ; p<0.01 ) and hgb ( r=057 ; p<0.01 ) , and inversely correlated with plt ( r=0.18 ; p<0.01 ) ( figures 1 and 2 ) .
one year after src treatment , we observed significant reduction in hct , rbc , and hgb and no change in plt ( table 3 ) .
the mean map preoperatively and postoperatively was equal to 106.3 mmhg and 106.1 mmhg respectively ( figure 3 ) .
however , positive response in patients with hypertension was observed . of 91 patients with hypertension , 56 ( 61.7% )
fifteen patients ( 16.4% ) had only antihypertensive drugs dose reduction and 20 ( 21.9% ) patients had stable hypertension .
recurrence occurred more frequently in patients who underwent cyst aspiration and sclerotherapy ; the rate was 43.3% ( 13 patients ) .
the recurrence rate in the laparoscopic group in 10-year follow - up was 2.9% ( 4 patients ) and 4.4% ( 2 pts ) in the retroperitoneoscopic group .
complications occurred in 15 ( 7.4% ) patients , of whom 10 ( 4.7% ) were grade i , 4 ( 1.9% ) were grade ii , and 1 ( 0.4% ) was grade iii in clavien classification .
it is well known that patients with long - term chronic kidney disease ( ckd ) require erythropoietin ( epo ) supplementation .
however , patients with ckd due to adpkd usually have normal red blood cell values due to high epo concentration in plasma and in the cyst fluid .
attar et al . showed that patients with unilateral cystic disease as well as patients with adpkd may have polycythemia .
hct , rbc , and hgb may serve as indirect equivalents of plasma epo concentration . as shown ,
these parameters are significantly increased in patients with src in comparison with a cohort of patients without src .
in addition we found a positive correlation between cyst burden and the parameters mentioned above .
our results show that plt count was lower in the experimental group . in our opinion
it was shown that recurrent urinary tract obstruction and infection may lead to reactive thrombocytosis .
the prevalence of hypertension in patients with src is about 40% , as confirmed by our results .
one concept of such etiopathology is that the enlarged cyst compresses renal parenchyma , which results in decreased blood flow through the kidney and increased rennin production .
although we did not observe reduction of map in our experimental group after the operation , we believe the positive effect is notable .
the positive effect was observed in 71 ( 78% ) patients , especially in patients with diagnosed hypertension .
other authors have also confirmed the positive effect of cyst treatment on blood pressure reduction .
laparoscopic and retroperitoneoscopic decortication of the srcs showed excellent results in terms of pain release and low recurrence rate .
the high recurrence rate in patients treated with aspiration and sclerotherapy indicates that such treatment should be avoided whenever possible in favor of a laparoscopic / retroperitoneoscopic approach .
however , comorbidities usually preclude such an approach and make aspiration the only possible treatment .
our outcomes are similar to data obtained previously . in case of recurrence after aspiration and sclerotherapy
most of the complications were grade i , most commonly increased body temperature requiring antipyretics .
grade ii complications occurred in patients with prolonged pyrexia , who required additional doses of antibiotics .
the only patient with a grade iii complication had inadvertent diaphragm incision into the pleura and required suction drainage .
patients with src have high values of hct , hgb , and rbc , probably due to increased erythropoietin concentration .
laparoscopic and retroperitoneoscopic surgery is characterized by low recurrence rate , in contrast to aspiration and sclerotherapy approach . | backgroundthe simple renal cyst is the most common benign kidney disease .
it may cause pain and hypertension , especially if significantly enlarged . as in polycystic kidney disease , blood cell count disturbances
are frequently observed in simple renal cysts .
the aim of our study was to assess such disturbances , changes in blood pressure , and complication rate in our patients undergoing surgery due to simple renal cyst in the last 10 years.material/methods210 patients with simple renal cysts were underwent surgery between 2002 and 2012 .
two different kinds of operation were conducted : aspiration of cyst fluid with injection of sclerosing agent , and laparoscopic / retroperitoneoscopic decortications of the cyst wall .
a control group comprised 134 patients with benign prostate hyperplasia .
the following data were obtained : cyst burden , hematocrit , hemoglobin , red blood cells , thrombocytes , occurrence of pain , and blood pressure before and after the operation .
complications were collected and presented in clavien score.resultshematocrit , hemoglobin , and red blood cells were significantly increased in the experimental group .
a positive correlation was observed between cyst burden and the parameters mentioned above .
of 91 patients with hypertension , 56 ( 61.7% ) had blood pressure reduction after the operation .
treatment relieved the loin pain in 132 ( 88% ) patients .
complications occurred in 15 ( 7.4% ) patients.conclusionspatients with simple renal cysts have high values of red blood cells , hematocrit , and hemoglobin .
treatment decreases blood pressure in patients with hypertension .
complications after treatment are rare and mild . |
this paper is a continuation of @xcite , where deterministic scaled equations describing the dynamics of a massive piston in a cubical container filled with ideal gas were given .
here we state exact conditions on the validity of those equations and outline the arguments .
full proofs will be published in a separate paper @xcite .
we refer the reader to @xcite and to @xcite as well as @xcite for a detailed description of the problem of a massive piston moving in a cylinder . here
we just recall necessary facts .
consider a cubical domain @xmath5 of size @xmath0 separated into two parts by a wall ( piston ) , which can move freely without friction inside @xmath5 .
each part of @xmath5 is filled by a noninteracting gas of particles , each of mass @xmath3 .
the piston has mass @xmath6 and moves along the @xmath7-axis under the action of elastic collisions with the particles .
the size @xmath0 of the cube is a large parameter of the model , and we are interested in the limit behavior as @xmath8 . the mass @xmath3 of gas particles is fixed .
we will assume that @xmath9 grows proportionally to @xmath10 and the number of gas particles @xmath11 is proportional to @xmath12 , while their velocities remain of order one .
the position of the piston at time @xmath13 is specified by a single coordinate @xmath14 , @xmath15 , its velocity is then given by @xmath16 .
since the components of the particle velocities perpendicular to the @xmath7-axis play no role in the dynamics , we may assume that each particle has only one coordinate , @xmath7 , and one component of velocity , @xmath17 , directed along the @xmath7-axis .
when a particle with velocity @xmath17 hits the piston with velocity @xmath18 , their velocities after the collision , @xmath19 and @xmath20 , respectively , are given by v^= ( 1-)v + v [ v ] v^= -(1-)v + ( 2-)v [ v ] where @xmath21 .
we assume that @xmath22 , where @xmath23 is a constant , so that = = [ varepsmm ] when a particle collides with a wall at @xmath24 or @xmath25 , its velocity just changes sign .
the evolution of the system is completely deterministic , but one needs to specify initial conditions .
we shall assume that the piston starts at the midpoint @xmath26 with zero velocity @xmath27 .
the initial configuration of gas particles is chosen at random as a realization of a ( two - dimensional ) poisson process on the @xmath28-plane ( restricted to @xmath29 ) with density @xmath30 , where @xmath31 is a function satisfying certain conditions , see below , and the factor of @xmath10 is the cross - sectional area of the container .
in other words , for any domain @xmath32\times\ir^1 $ ] the number of gas particles @xmath33 at time @xmath34 has a poisson distribution with parameter @xmath35 .
let @xmath36 denote the space of all possible configurations of gas particles in @xmath5 .
for each realization @xmath37 the piston trajectory will be denoted by @xmath38 and its velocity by @xmath39 .
as @xmath8 , space and time are rescaled as y = x / l and = t / l .
[ ytau ] which is a typical rescaling for the hydrodynamic limit transition ( see @xcite for motivation and physical discussion ) .
we call @xmath40 and @xmath41 the _ macroscopic _ ( `` slow '' ) variable , as opposed to the original _ microscopic _ ( `` fast '' ) @xmath7 and @xmath13
. now let y_l(,)=x_l(l,)/l , w_l(,)=v_l(l , ) [ ywl ] be the position and velocity of the piston in the macroscopic variables .
the initial density @xmath31 satisfies @xmath42 where the function @xmath43 is independent of @xmath0 . without loss of generality , assume that @xmath44 is normalized so that @xmath45 then the mean number of particles in the entire container @xmath5 is equal exactly to @xmath46 in order to describe the dynamics by differential equations , we assume that the function @xmath43 satisfies several technical requirements stated below . * _ smoothness_. @xmath43 is a piecewise @xmath47 function with uniformly bounded partial derivatives , i.e.@xmath48 and @xmath49 for some @xmath50 . * _ discontinuity lines_. @xmath43 may be discontinuous on the line @xmath51 ( i.e. , `` on the piston '' ) .
in addition , it may have a finite number ( @xmath52 ) of other discontinuity lines in the @xmath53-plane with strictly positive slopes ( each line is given by an equation @xmath54 where @xmath55 is @xmath47 and @xmath56 ) . *
_ density bounds_. let _ 0(y , v)>_>0 for v_1<|v|<v_2 [ pmin0 ] for some @xmath57 , and _
y , v_0(y , v)= _ < [ pmax0 ] the requirements ( [ pmin0 ] ) and ( [ pmax0 ] ) basically mean that @xmath43 takes values of order one .
* _ velocity `` cutoff''_. let _
0(y , v ) = 0 , |v| v_min |v| v _ [ 0cutoff ] with some @xmath58 .
this means that the speed of gas particles is bounded from above by @xmath59 and from below by @xmath60 . * _ approximate pressure balance_. @xmath43 must be nearly symmetric about the piston , i.e. |_0(y , v)-_0(1-y ,- v)|<_0 [ 0symmetry ] for all @xmath61 and some sufficiently small @xmath62 . the requirements ( p4 ) and ( p5 ) are made to ensure that the piston velocity @xmath63 will be smaller than the minimum speed of the particles , with probability close to one , for times @xmath64 .
such assumptions were first made in @xcite .
we think of @xmath65 , @xmath66 , @xmath67 , @xmath68 , @xmath69 , @xmath70 , @xmath60 , @xmath59 , @xmath71 and @xmath72 in ( p1)(p4 ) as fixed ( global ) constants and @xmath73 in ( p5 ) as an adjustable small parameter .
we will assume throughout the paper that @xmath73 is small enough , meaning that @xmath74 it is important to note that the hydrodynamic limit does _ not _ require that @xmath75 .
the parameter @xmath73 stays positive and fixed as @xmath8 .
here is our main result : there is an @xmath0-independent function @xmath76 defined for all @xmath77 and a positive @xmath78 ( actually , @xmath79 as @xmath75 ) , such that _ 0 _ |y_l ( , ) - y()| 0 [ yy ] and _ 0 _ |w_l ( , ) - w()| 0 [ ww ] in probability , as @xmath8 . here
[ tmmain ] this theorem establishes the convergence in probability of the random functions @xmath81 characterizing the mechanical evolution of the piston to the deterministic functions @xmath82 , in the hydrodynamic limit @xmath8 . the functions @xmath76 and @xmath83 satisfy certain ( euler - type ) differential equations stated in the next section .
those equations have solutions for all @xmath77 , but we can only guarantee the convergence ( [ yy ] ) and ( [ ww ] ) for @xmath84 .
what happens for @xmath85 , especially as @xmath86 , remains an open problem .
some experimental results and heuristic observations in this direction are presented in @xcite and discussed in section 4 .
* remark 1*. the function @xmath76 is at least @xmath47 and , furthermore , piecewise @xmath87 on the interval @xmath88 .
its first derivative @xmath89 ( velocity ) and its second derivative @xmath90 ( acceleration ) remain @xmath73-small : @xmath91 ) and ( [ ww ] ) : there is a @xmath92 ( @xmath93 ) such that @xmath94 for @xmath95 and @xmath96 for @xmath97 .
the same bounds are valid for @xmath98 .
these estimates hold with `` overwhelming '' probability , specifically they hold for all @xmath99 such that @xmath100 .
the equations describing the deterministic function @xmath76 involve another deterministic function the density of the gas @xmath101 .
initially , @xmath102 , and for @xmath103 the density @xmath101 evolves according to the following rules . *
_ free motion_. inside the container the density satisfies the standard continuity equation for a noninteracting particle system without external forces : ( + v ) ( y , v,)=0 [ pdinside ] for all @xmath40 except @xmath104 , @xmath105 and @xmath106 .
equation ( [ pdinside ] ) has a simple solution ( y , v,)=(y - vs , v ,-
s ) [ pinside ] for @xmath107 such that @xmath108 for all @xmath109 . equation ( [ pinside ] ) has one advantage over ( [ pdinside ] ) : it applies to all points @xmath53 , including those where the function @xmath110 is not differentiable . * _ collisions with the walls_. at the walls @xmath104 and @xmath105 we have ( 0,v , ) = ( 0,-v , ) [ pwall0 ] ( 1,v , ) = ( 1,-v , ) [ pwall1 ] * _ collisions with the piston_. at the piston @xmath106 we have @xmath111 where @xmath17 represents the velocity after the collision and @xmath112 that before the collision ; here w ( ) = y ( ) [ w = y ] is the ( deterministic ) velocity of the piston .
it remains to describe the evolution of @xmath83 .
suppose the piston s position at time @xmath41 is @xmath113 and its velocity @xmath114 .
the piston is affected by the particles @xmath53 hitting it from the right ( such that @xmath115 and @xmath116 ) and from the left ( such that @xmath117 and @xmath118 ) .
accordingly , we define the density of the particles colliding with the piston ( `` density on the piston '' ) by q(v,;y , w)=\ { ll ( y+0,v , ) & if v < w + ( y-0,v , ) & if v > w + .
[ qp ] * _ piston s velocity_. the velocity @xmath119 of the piston must satisfy the equation _
-^ ( v - w)^2sgn ( v - w ) q(v,;y , w ) dv = 0 [ quadraticint ] we also remark that for @xmath103 , when ( [ ponpiston ] ) holds , @xmath120 i.e. the piston s velocity is the average of the nearby particle velocities on each side . the system of ( hydrodynamical ) equations ( h1)(h4 ) is now closed and , given appropriate initial conditions , should completely determine the functions @xmath76 , @xmath83 and @xmath121 for @xmath103 . to specify the initial conditions
, we set @xmath122 and @xmath123
. the initial velocity @xmath124 does not have to be specified , it comes `` for free '' as the solution of the equation ( [ quadraticint ] ) at time @xmath125 .
it is easy to check that the initial speed @xmath126 will be smaller than @xmath60 , in fact @xmath127 as @xmath75 in ( p5 ) .
note that if the initial conditions at @xmath125 do not satisfy ( [ pwall0])([ponpiston ] ) , there will be a discontinuity in @xmath128 as @xmath129 ( see also remark 4 below ) .
equation ( [ quadraticint ] ) has a unique solution @xmath114 as long as the piston interacts with some gas particles on both sides , i.e.as long as @xmath130 indeed , the left hand side of ( [ quadraticint ] ) is a continuous and strictly monotonically decreasing function of @xmath114 , and it takes both positive and negative values . the solution @xmath83 may not be continuous in @xmath41 , though .
but if @xmath101 is piecewise @xmath47 and has a finite number of discontinuity lines with positive slopes ( as we require of @xmath43 in section [ seci ] ) , then @xmath83 will be continuous and piecewise differentiable . .
one can easily check that the total mass @xmath131 and the total kinetic energy @xmath132 remain constant along any solution of our system of equations ( h1)(h4 ) .
also , the mass in the left and right part of @xmath5 separately remains constant .
equation ( [ quadraticint ] ) also preserves the total momentum of the gas @xmath133 , but it changes due to collisions with the walls . .
previously , lebowitz , piasecki and sinai @xcite studied the piston dynamics under essentially the same initial conditions as our ( p1)(p5 ) .
they argued heuristically that the piston dynamics could be approximated by certain deterministic equations in the original ( microscopic ) variables @xmath7 and @xmath13 .
the deterministic equations found in @xcite correspond to our ( [ pinside])([w = y ] ) with obvious transformation back to the variables @xmath134 , but our main equation ( [ quadraticint ] ) has a different counterpart in the context of @xcite , which reads v(t)=a [ tquadraticint ] here @xmath135 and @xmath136 denote the deterministic position and velocity of the piston and @xmath137 the density of the gas ( the constant @xmath138 appeared in ( [ varepsmm ] ) ) .
we refer to @xcite for more details and a heuristic derivation of ( [ tquadraticint ] ) .
since ( [ tquadraticint ] ) , unlike our ( [ quadraticint ] ) , is a differential equation , the initial velocity @xmath139 has to be specified separately , and it is customary to set @xmath140 .
alternatively , one can set @xmath141 , see @xcite . equation ( [ tquadraticint ] ) can be reduced to ( [ quadraticint ] ) in the limit @xmath8 as follows
. one can show ( we omit details ) that ( [ tquadraticint ] ) is a dissipative equation whose solution with any ( small enough ) initial condition @xmath139 converges to the solution of ( [ quadraticint ] ) during a @xmath13-time interval of length @xmath142 .
that interval has length @xmath143 on the @xmath41 axis , and so it vanishes as @xmath8 , this is why we replace ( [ tquadraticint ] ) with ( [ quadraticint ] ) and ignore the initial condition @xmath139 when working with the thermodynamic variables @xmath41 and @xmath40 . the equation ( [ tquadraticint ] )
is not used in this paper .
we now describe the solution of our equations ( h1)-(h4 ) in more detail .
assume that for some @xmath144 the gas density @xmath101 satisfies the same requirements ( p1)-(p4 ) as those imposed on the initial function @xmath43 in sect .
[ seci ] , with constants @xmath145 , @xmath146 , @xmath147 , @xmath148 , @xmath149 , @xmath150 , @xmath151 , @xmath152 , @xmath153 and @xmath154 , whose values are not essential , but are independent of @xmath41 .
we also assume an analogue of ( p5 ) , but this one is not so straightforward , since the piston does not have to stay at the middle point @xmath155 at any time @xmath156 .
we require that |y()-0.5|<_0 [ y05 ] and for any point @xmath53 with @xmath157 there is another point @xmath158 `` across the piston '' ( i.e. such that @xmath159 ) satisfying [ symmetry ] for some sufficiently small @xmath160 . actually , the map @xmath161 , which we denote by @xmath162 , is one - to - one and will be explicitly constructed below .
the constant @xmath163 here , just like @xmath73 in ( p5 ) , is assumed to be small enough , and moreover _ 0 <
c_0_0 [ ee0 ] with some constant @xmath164 . we now derive elementary but important consequences of the above assumptions . since the density @xmath101 vanishes for @xmath165 ,
so does the function @xmath166 defined by ( [ qp ] ) .
moreover , for all @xmath167 , the function @xmath166 will be independent of @xmath114 , and so we can write it as @xmath168 . also , equation ( [ quadraticint ] ) can be simplified : the factor sgn@xmath169 can be replaced by sgn@xmath170 .
then , expanding the square in ( [ quadraticint ] ) reduces it to a quadratic equation for @xmath114 : q_0w^2 - 2q_1w+q_2 = 0 [ quadratic ] where q_0= vq(v,;y ) dv [ q0 ] q_1=v sgn vq(v,;y ) dv [ q1 ] q_2=v^2 sgn vq(v,;y ) dv [ q2 ] with @xmath171 .
the integrals @xmath172 have the following physical meaning : @xmath173 @xmath174 @xmath175 where @xmath176 represent the total mass , momentum and energy of the incoming gas particles ( per unit length ) on the left hand side of the piston , and @xmath177 those on the right hand side of it .
the value @xmath178 also represents the net pressure exerted on the piston by the gas as if the piston did not move .
of course , if @xmath179 , then we must have @xmath180 , which agrees with ( [ quadratic ] ) . next , under the above requirements on @xmath101 , the function @xmath168 is , in a certain sense , nearly symmetric in @xmath17 about @xmath181 ( see @xcite for details )
this fact implies that @xmath182 and @xmath178 are small , more precisely \{|q_0|,|q_2|}c_0 [ q0q2 ] where @xmath183 is a constant depending on the parameters @xmath184 , etc .
, but not on @xmath73 . at the same time
, the assumption ( p3 ) guarantees that q_1q_1,>0 [ q1min ] where @xmath185 is a constant depending on @xmath186 , etc . , but not on @xmath73 .
if @xmath73 is small enough , there is a unique root of the quadratic polynomial ( [ quadratic ] ) on the interval @xmath187 , which corresponds to the only solution of ( [ quadraticint ] ) . since this root is smaller , in absolute value , than the other root of ( [ quadratic ] ) , it can be expressed by w()= [ wroot ] where the sign before the radical is `` @xmath188 '' , not `` @xmath189 ''
of course , ( [ wroot ] ) applies whenever @xmath190 , while for @xmath191 we simply have @xmath192 .
( [ q0q2])-([wroot ] ) imply an upper bound on the piston velocity : @xmath193 for some constant @xmath194 depending on @xmath184 , etc . , but not on @xmath73 .
a similar bound holds for the piston acceleration @xmath195 , since @xmath196 and @xmath197const@xmath198 , see @xcite for more details .
next we consider the evolution of a point @xmath53 in the domain @xmath199 under the rules ( h1)(h3 ) , i.e. as it moves freely with constant velocity and collides elastically with the walls and the piston .
denote by @xmath200 its position and velocity at time @xmath77 .
then ( h1 ) translates into @xmath201 and @xmath202 whenever @xmath203 , ( h2 ) becomes @xmath204 whenever @xmath205 , and ( h3 ) gives ( y_+0,v_+0)=(y_-0,2w()-v_-0 ) [ tildefpiston ] whenever @xmath206 .
note that ( [ tildefpiston ] ) corresponds to a special case of the mechanical collision rules ( [ v])([v ] ) with @xmath207 ( equivalently , @xmath208 ) .
hence the point @xmath53 moves in @xmath209 as if it was a gas particle with zero mass .
the motion of points in @xmath53 is described by a one - parameter family of transformations @xmath210 defined by @xmath211 for @xmath103 .
we will also write @xmath212 . according to ( h1)(h3 ) ,
the density @xmath101 satisfies a simple equation ( y_,v_,)= ( f^-(y_,v_),0 ) = _ 0(y_0,v_0 ) [ pfp ] for all @xmath77 . also , it is easy to see that for each @xmath103 the map @xmath213 is one - to - one and preserves area , i.e. @xmath214 .
now , because of ( p4 ) , the initial density @xmath43 can only be positive in the region @xmath215 hence we will restrict ourselves to points @xmath216 only . at any time @xmath103
, the images of those points will be confined to the region @xmath217 . in particular , @xmath218 for @xmath219 .
the map @xmath220 involved in ( [ rtau ] ) and ( [ symmetry ] ) can now be defined as @xmath221 , where @xmath222 is a simple reflection `` across the piston '' at time @xmath125 .
we now make an important observation .
if a fast point @xmath200 collides with a slow piston , @xmath223 with the piston occur at well separated time moments , which allows us to effectively count them . for @xmath224 @xmath225
is the number of collisions of the point @xmath53 with the piston during the interval @xmath226 . for each @xmath103 ,
we partition the region @xmath227 into subregions @xmath228 so @xmath229 is occupied by the points that at time @xmath41 have experienced exactly @xmath230 collisions with the piston during the interval @xmath226 .
now , for each @xmath231 we define @xmath232 to be the first time when a point @xmath233 experiences its @xmath234-st collision with the piston , i.e. @xmath235 in particular , @xmath92 is the earliest time when a point @xmath233 experiences its first recollision with the piston .
hence , no recollisions occur on the interval @xmath236 , and we call it the _ zero - recollision interval_. similarly , on the interval @xmath237 no more than one recollision with the piston is possible for any point , and we call it the _ one - recollision interval_. the time moment @xmath238 mentioned in theorem [ tmmain ] is the earliest time when a point @xmath233 either experiences its third collision with the piston or has its second collision with the piston given that the first one occurred after @xmath239 .
hence , @xmath240 , and actually @xmath238 is very close to @xmath241 , see below .
the following theorem summarizes the properties of the solutions of the hydrodynamical equations ( h1)(h4 ) .
let @xmath242 be given .
if the initial density @xmath43 satisfies ( p1)(p5 ) with a sufficiently small @xmath73 , then * the solution of our hydrodynamical equations ( h1)(h4 ) exists and is unique on the interval @xmath243 ; * the density @xmath101 satisfies conditions similar to ( p1)(p4 ) for all @xmath244 , it also satisfies ( [ y05])([ee0 ] ) ; * the piston velocity and acceleration remain small , @xmath245 and @xmath246 ; * we have @xmath247 for all @xmath248 , and if @xmath249 , then also @xmath250 . [ tmprop ] if @xmath251 , so that the initial density @xmath43 is completely symmetric about the piston , the solution is trivial : @xmath252 and @xmath253 for all @xmath103 .
[ crprop ]
lastly , we demonstrate the reason for our assumption that all the discontinuity curves of the initial density @xmath43 must have positive slopes
. it would be quite tempting to let @xmath43 have more general discontinuity lines , e.g. allow it be smooth for @xmath254 and abruptly drop to 0 at @xmath255 and @xmath256 .
the following example shows why this is not acceptable .
* example*. suppose the initial density @xmath43 has a horizontal discontinuity line @xmath257 ( say , @xmath258 or @xmath259 ) .
after one interaction with the piston the image of this discontinuity line can oscillate up and down , due to the fluctuations of the piston acceleration ( fig . 1 ) .
as time goes on , this oscillating curve will `` travel '' to the wall and come back to the piston , experiencing some distortions on its way , caused by the differences in velocities of its points ( fig . 1 ) .
when this curve comes back to the piston again , it may well have `` turning points '' where its tangent line is vertical , or even contain vertical segments of positive length .
this produces unwanted singularities or even discontinuities of the piston velocity and acceleration .
the same phenomena can also occur when a discontinuity line of the initial density @xmath43 has a negative slope .
our proof of theorem [ tmmain ] is based on large deviation estimates for the poisson random variable : let @xmath260 be a poisson random variable with parameter @xmath261 . for any @xmath262 there is a @xmath263 such that for all @xmath264 we have @xmath265 [ lmpoi ] this shows that the probabilities of large deviations rapidly decay , as they do for the gaussian distribution .
the principal step in our proof of theorem [ tmmain ] is the velocity decomposition scheme described next .
let @xmath39 be the velocity of the piston at time @xmath266 for a random configuration of particles @xmath37 .
let @xmath267 be a small time increment .
then the law of elastic collision ( [ v ] ) implies v_l(t+t,)=(1-)^kv_l(t , ) + _ j=1^k(1-)^k - jv_j [ main ] here @xmath268 is the number of particles colliding with the piston during the time interval @xmath269 , and @xmath270 are their velocities numbered in the order in which the particles collide .
we rearrange the formula ( [ main ] ) as follows : v_l(t+t,)=(1-k)v_l(t , ) + _ j=1^k
v_j+^(1)+^(2 ) [ main1 ] where @xmath271\ ] ] and @xmath272\ ] ] let us assume that the fluctuations of the velocity @xmath273 on the interval @xmath269 , are bounded by some quantity @xmath274 : _
s(t , t+t ) |v_l(s , ) - v_l(t,)| v [ deltav ] consider two regions on the @xmath275 plane : d_1=\{(x , v ) :
< - , v_<|v|<v _ } [ d1 ] and d_2=\{(x , v ) :
< - , v_<|v|<v _ } [ d2 ] each of them is a union of two trapezoids @xmath276 , @xmath277 , where @xmath278 denotes the upper and @xmath279 the lower trapezoid , see fig . 2 .
note that @xmath280 .
the bound ( [ deltav ] ) implies that all the particles in the region @xmath65 necessarily collide with the piston during the time interval @xmath269 .
moreover , the trajectory of every point @xmath281 hits the piston within time @xmath282 .
the bound ( [ deltav ] ) also implies that all the particles actually colliding with the piston during the interval @xmath269 are contained in @xmath283 .
let us denote by @xmath284 the number of particles in the regions @xmath285 for @xmath286 at time @xmath13 .
we also denote by @xmath287 the number of particles actually colliding with the piston `` on the left '' , and by @xmath288 that number `` on the right '' ( of course , @xmath289 ) . due to the above observations , @xmath290 .
now , suppose that @xmath291 .
then we show that for typical configurations @xmath292 the particles in each domain @xmath293 , @xmath286 , have never collided with the piston before .
therefore , their number , @xmath284 , @xmath286 , satisfies the laws of poisson distribution , in particular , the large deviation estimate in lemma [ lmpoi ] applies .
this gives the bound ( for typical @xmath292 )
_ 1 ^ -k_1^ k^ _ 2^+k_2^ [ lkl ] where @xmath294 and @xmath295 corresponds to the action of @xmath296 in the original time - space coordinates @xmath134 .
the deviations @xmath297 in ( [ lkl ] ) can be adjusted by using lemma [ lmpoi ] .
the difference @xmath298 is estimated by @xmath299 by putting all these estimates together we get tight bounds on @xmath300 in ( [ main1 ] ) .
similarly we get bounds on @xmath301 in ( [ main1 ] ) .
the following is the final result of this analysis : v_l(t+t,)-v_l(t,)= d(t , ) t + _ 3 [ vv ] here ( t,)=a [ q_0v_l^2(t,)-2q_1v_l(t,)+q_2 ] [ cald ] and @xmath172 are defined similarly to ( [ q0])-([q2 ] ) , in which @xmath76 must be replaced by the actual piston position @xmath302 .
the error term @xmath303 in ( [ vv ] ) is bounded by |_3| [ chibound ] which corresponds to brownian motion - type random fluctuations .
the term @xmath304 in ( [ vv ] ) represents the main ( `` deterministic '' ) force acting on the piston .
the term @xmath303 describes random fluctuations of that force . when the piston velocity stabilizes , then the main force @xmath305 should vanish , and an `` equilibrium '' velocity @xmath306 will be established . the latter is the root of the equation @xmath307 , which is to @xmath308 is that @xmath305 is almost proportional to @xmath309 , i.e. @xmath310 for some constants @xmath311 .
in fact , @xmath306 is a very slowly changing function of @xmath13 , whose derivative is small : @xmath312 . as a result
, @xmath313 will always stay close to @xmath308 , more precisely |v_l(t,)-|v_l(t,)| < constl^-1l [ vbarv ] on the entire zero - recollision interval @xmath314 .
now , the piston coordinate @xmath315 is the solution of the differential equation @xmath316 where @xmath317 by ( [ vbarv ] ) . on the other hand ,
the deterministic piston coordinate @xmath76 is the solution of the equation @xmath318 , and both @xmath319 and @xmath114 are given by the same radical expression , cf .
( [ wroot ] ) and ( [ vroot ] ) .
lastly , a simple application of gronwall s inequality completes the proof of theorem [ tmmain ] on the zero - recollision interval @xmath320 .
the proof on the one - recollision interval @xmath321 goes along the same lines .
one major difference is that the number of particles @xmath284 , @xmath286 , in the domain @xmath285 constructed in the velocity decomposition scheme is no longer a poisson variable , so lemma [ lmpoi ] does not apply directly . to handle this new situation
, we pull the domain @xmath285 back in time , as we did before .
but now that pullback involves one interaction with the piston ( corresponding to the first collision of the particles in @xmath285 with the piston , which occurs during the zero - recollision interval @xmath314 ) .
since the piston position and velocity at the moment of that first collision are random , the preimage of @xmath285 will be a random domain .
its shape will depend on the piston velocity @xmath322 during the zero - recollision interval @xmath314 .
we observe that the boundary of the preimage of @xmath285 is described by a random , yet hlder continuous function , and its hlder exponent is @xmath323 due to ( [ chibound ] )
. then we pick a small @xmath324 and construct a @xmath325-dense set in the space of all hlder continuous functions in the spirit of a work by kolmogorov and tihomirov @xcite .
the elements of that @xmath325-dense set can be used to construct a finite collection of ( nonrandom ) domains , so that one of them will approximate the ( random ) preimage of our @xmath285 ( we need to select the small @xmath324 carefully to ensure sufficient accuracy of the approximation ) .
now the number of particles in our random domain ( the preimage of @xmath285 ) can be approximated by the number of particles in the corresponding nonrandom domain .
the latter has poisson distribution , and finally we can apply lemma [ lmpoi ] .
this trick gives necessary estimates on @xmath284 .
a full proof of theorem [ tmmain ] is given in @xcite . at present , we do not know if this theorem can be extended beyond the critical time @xmath238 , this is an open question .
some other open problems are discussed in the next section .
\1 . the main goal of this work is to prove that under suitable initial conditions random fluctuations in the motion of a massive piston are small and vanish in the thermodynamic limit .
we are , however , able to control those fluctuations effectively only as long as the surrounding gas particles can be described by a poisson process , i.e. during the zero - recollision interval @xmath95 . in that case
the random fluctuations are bounded by const@xmath326 , see remark 2 after theorem [ tmmain ] . up to the logarithmic factor ,
this bound is optimal , see @xcite and earlier estimates by holley @xcite , drr et al .
@xcite . during the one - recollision interval @xmath327
, the situation is different .
the probability distribution of gas particles that have experienced one collision with the piston is no longer a poisson process , it has intricate correlations .
we are only able to show that random fluctuations remain bounded by @xmath328 , see again remark 2 .
perhaps , our bound is far from optimal , but our numerical experiments reported in @xcite show that random fluctuations indeed grow during the one - recollision interval .
we have tested numerically whether random fluctuations remained small after more than one recollision , i.e. at times @xmath329 .
we found that for some initial @xmath44 they actually increased very rapidly , and we conjectured that the rate of increase was exponential in @xmath41 .
we found , indeed , that at times @xmath330 the fluctuations became large even on a macroscopic scale , and then many unexpected phenomena occurred @xcite .
interestingly , the exponential growth of random fluctuations seems to be related to the instability of our hydrodynamical equations .
we found that small perturbations of the initial density @xmath44 can grow exponentially in @xmath41 under certain conditions , matching the growth of random fluctuations of the piston motion in the mechanical model .
we refer the reader to @xcite for further discussion and to our work in progress @xcite .
it is clear that in our model recollisions of gas particles with the piston have a very `` destructive '' effect on the dynamics in the system .
however , we need to distinguish between two types of recollisions .
we say that a recollision of a gas particle with the piston is _ long _ if the particle hits a wall @xmath24 or @xmath25 between the two consecutive collisions with the piston .
otherwise a recollision is said to be _
short_. long recollisions require some time , as the particle has to travel all the way to a wall , bounce off it , and then travel back to the piston before it hits it again .
short recollisions can occur in rapid succession .
we have imposed the velocity cut - off ( p4 ) in order to avoid any recollisions for at least some initial period of time ( which we call the zero - recollision interval ) .
more precisely , the upper bound @xmath59 guarantees the absence of long recollisions . without it , we would have to deal with arbitrarily fast particles that dash between the piston and the wall very many times in any interval @xmath226 . on the other hand ,
the lower bound @xmath60 was assumed to exclude short recollisions .
there are good reasons to believe , though , that short recollisions may not be so destructive for the piston dynamics . indeed , let a particle experience two or more collisions with the piston in rapid succession ( i.e. without hitting a wall in between ) .
this can occur in two cases : ( i ) the particle s velocity is very close to that of the piston , or ( ii ) the piston s velocity changes very rapidly
. the latter should be very unlikely , since the deterministic acceleration of the piston is very small , cf.theorem [ tmprop]c . in case ( i )
, the recollisions should have very little effect on the velocity of the piston according to the rule ( [ v ] ) , so that they may be safely ignored , as it was done already in earlier studies @xcite .
\3 . in our paper
, @xmath0 plays a dual role : it parameterizes the mass of the piston ( @xmath1 ) , and it represents the length of the container ( @xmath29 ) .
this duality comes from our assumption that the container is a cube .
however , our model is essentially one - dimensional , and the mass of the piston @xmath9 and the length of the interval @xmath29 can be treated as two independent parameters . in particular , we can assume that the container is infinitely long in the @xmath7 direction ( so , _ that _ @xmath0 is infinite ) , but the mass of the piston is still finite and given by @xmath1 .
in this case there are no recollisions with the piston , as long as its velocity remains small .
hence , our zero - recollision interval is effectively infinite . as a result ,
theorem [ tmmain ] can be extended to arbitrarily large times .
precisely , for any @xmath242 we can prove the convergence in probability : @xmath332 and @xmath333 as @xmath8 , where @xmath334 is a constant and @xmath76 and @xmath80 are the solutions of the hydrodynamical equations described in section 2 . \4 . along the same lines as above
, we can assume that the container is @xmath325-dimensional with @xmath335 .
then the mass of the piston and the density of the particles are proportional to @xmath336 rather than @xmath10 .
when @xmath325 is large , the gas particles are very dense on the @xmath275 plane .
this leads to a much better control over fluctuations of the particle distribution and the piston trajectory . as a result ,
theorem [ tmmain ] can be extended to the @xmath300-recollision interval @xmath337 , where @xmath338 depends on @xmath325 .
it can be shown that for any @xmath338 there is a @xmath339 such that for all @xmath340 the convergence ( [ yy ] ) and ( [ ww ] ) holds with @xmath341 .
therefore , a higher dimensional piston is more stable than a lower dimensional one
. it would be interesting to investigate other modifications of our model that lead to more stable regimes .
for example , let the initial density @xmath43 of the gas depend on the factor @xmath342 in such a way that @xmath343 , where @xmath344 is a fixed function .
then the particle density grows as @xmath345 .
this is another way to increase the density of the particles , but without changing the dimension .
one may expect a better control over random fluctuations in this case , too .
* acknowledgements*. n. chernov was partially supported by nsf grant dms-9732728 .
j. lebowitz was partially supported by nsf grant dmr-9813268 and by air force grant f49620 - 01 - 0154 . ya .
sinai was partially supported by nsf grant dms-9706794 .
this work was completed when n. c. and j. l. stayed at the institute for advanced study with partial support by nsf grant dms-9729992 .
a. n. kolmogorov , v. m. tihomirov , _ @xmath346-entropy and @xmath347-capacity of sets in function spaces _ ,
* 17 * ( 1961 ) , 277364 .
j. l. lebowitz , j. piasecki , and ya .
sinai , _ scaling dynamics of a massive piston in an ideal gas_. in : hard ball systems and the lorentz gas , 217227 , encycl .
, * 101 * , springer , berlin , 2000 . | we continue the study of the time evolution of a system consisting of a piston in a cubical container of large size @xmath0 filled with an ideal gas .
the piston has mass @xmath1 and undergoes elastic collisions with @xmath2 gas particles of mass @xmath3 . in a previous paper , lebowitz , piasecki and
sinai @xcite considered a scaling regime , with time and space scaled by @xmath0 , in which they argued heuristically that the motion of the piston and the one particle distribution of the gas satisfy autonomous coupled differential equations . here
we state exact results and sketch proofs for this behavior . 6.25 in 8.5 in .25 in [ section ] [ theorem]lemma [ theorem]sublemma [ theorem]proposition [ theorem]corollary [ theorem]remark _ dedicated to robert dorfman on the occasion of his 65@xmath4 birthday _ |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Homeland Infrastructure Power
Security and Assurance Incentives Act of 2003''.
SEC. 2. FINDINGS.
(a) Findings.--Congress finds that--
(1) In order to fortify and protect critical infrastructure
systems and facilities like military installations, banks,
utilities, and information technology systems from potential
terrorist threats and to provide efficient and assured power to
such facilities advanced technologies must be encouraged and
installed by U.S. electricity providers.
(2) Dependence on foreign oil is a matter of national
security and the nation must consider all energy resource
options, including support for energy efficiency and renewable
resources and technologies that will ensure a diverse energy
portfolio.
(3) Estimates are that power outages, brownouts, and other
voltage disturbances cost U.S. industry up to $150 billion per
year and cause great disruption to the Nation's economy.
(4) Distributed Power systems, such as fuel cells, turbines
and hybrid combinations of these technologies, backed up with
storage systems, can reduce costly outages, and ensure more
assured and secure and reliable power generation and
distribution, protected from potential terrorist threats to our
national infrastructure.
(b) Advanced Technology Incentives Program.--(1) The Secretary of
Energy shall establish within the Department of Energy an Advanced
Technology Incentives Program to make funding available, subject to
annual appropriation, to accelerate the development and deployment of
new advanced technologies such as fuel cells, turbines, hybrid, and
storage system power technologies.
(2) Advanced technology funding provided under this section shall
be used by the Secretary for payments to eligible owners or operators
to support efforts to reduce system costs, and improve the performance
and reliability of advanced distributed power generation and energy
storage systems. Payments made by the Secretary shall be used for the
purposes of demonstrating the capability of new technologies to
increase power generation through enhanced operational, economic, and
environmental performance.
(3) Payments under this section may only be made upon receipt by
the Secretary of an incentive payment application establishing that an
applicant is eligible to receive such payment as either--
(A) a qualifying advanced technology facility, or
(B) a qualifying security and assured power facility
(4) Incentive payments made by the Secretary under this section to
owners or operators of qualifying advanced technology facilities shall
be based on the number of kilowatt hours of electricity generated by
the facility through the use of an advanced technology during a 10-year
fiscal year period beginning with the fiscal year in which the
qualifying facility is first eligible for payment.
(5) A payment of 1.8 cents per kilowatt-hour shall be paid to the
owner or operator of a qualifying advanced technology facility under
this section. An additional 0.7 cents per kilowatt-hour shall be paid
to the owner or operator that is also a qualifying security and assured
power facility under this section. The amount of the payment made to
such qualifying facilities shall be adjusted for inflation for each
fiscal year of the program as determined by the Secretary. A facility
qualifying under this section shall be eligible for an incentive
payment up to, but not to exceed the first 10 million kilowatt-hours
produced in any fiscal year.
(c) Determination of a Security and Power Facility.--Within six
months after the date of enactment of this section, the Secretary, in
consultation with the Secretary of Homeland Security, shall--
(1) measure, evaluate and rate security and assurance
performance improvement,
(2) define the types of locations and facilities that would
most need the benefits of the improvements,
(3) determine the criteria for facilities that generate or
store and distribute electric energy that improves the
security, assurance, and reliability of the nation's
electricity grid and protects infrastructure including military
installations, financial institutions, medical and first
responder facilities, and other locations critical to the
security of the nation, and
(4) report back to the Committee on Energy and Commerce of
the United States House of Representatives on ways that
incentive payments under this section can accelerate the
introduction of technologies capable of providing the maximum
level of improvement and benefit to the public.
(d) Definitions.--For purposes of this section:
(1) Advanced technology.--The term ``advanced technology''
means an advanced fuel cell, turbine, hybrid, or storage system
power that is used to generate or store electric energy at or
in conjunction with a qualifying advanced technology facility.
(2) Qualifying advanced technology facility.--The term
``qualifying advanced technology facility'' means any facility
that generates electric energy from a power generation, storage
and distribution system.
(3) Qualifying security and assured power facility.--The
term ``qualifying security and assurance power facility'' means
a facility that also generates or stores and distributes
electric energy that improves the security and assures the
reliability of the nation's electricity infrastructure in
locations and facilities determined by the Secretary, in
consultation with the Secretary of Homeland Security, to be in
critical need of improvement and protection. The facility must
substantially reduce electric system vulnerabilities by
providing exceedingly secure, reliable, rapidly available, high
power quality electric energy to critical governmental,
commercial and industrial demand facilities.
(e) Authorization of Appropriations.--The following sums are
authorized to be apppropriated to carry out the purposes of this
section:
(1) For fiscal year 2004, $25,000,000.
(2) For fiscal year 2005, $50,000,000.
(3) For fiscal year 2006, $75,000,000.
(4) For fiscal year 2007, $100,000,000. | Homeland Infrastructure Power Security and Assurance Incentives Act of 2003 - Instructs the Secretary of Energy to establish within the Department of Energy an Advanced Technology Incentives Program to provide funding to accelerate development and deployment of new advanced technologies such as fuel cells, turbines, hybrid, and storage system power technologies.
Requires the use of such funding for: (1) eligible owners or operators to support efforts to reduce system costs, and improve the performance and reliability of advanced distributed power generation and energy storage systems; and (2) demonstrating the capability of new technologies to increase power generation through enhanced operational, economic, and environmental performance.
Directs the Secretary to: (1) evaluate security and assurance performance improvement; (2) define locations and facilities that would benefit most from such improvements; and (3) determine the criteria for facilities that generate or store and distribute electric energy that improves the security and reliability of the nation's electricity grid and protects locations critical to its security (including military installations, financial institutions, medical and first responder facilities). |
as one of the most compelling evidences for new physics beyond the standard model ( sm ) , the cosmic dark matter ( dm ) has been widely studied in particle physics @xcite .
recently , the cdms - ii collaboration observed three events which can be explained by a light dm with mass about 8.6 gev and a spin - independent dm - nucleon scattering cross section of about @xmath1 pb @xcite .
the existence of such a light dm seems to be corroborated by other direct detections such as the cogent @xcite , cresst @xcite and dama / libra @xcite .
moreover , a light dm is also hinted by fermi - lat , a satellite - based dm indirect detection experiment @xcite .
recent analysis of the fermi - lat data exhibits peaks in the gamma - ray spectrum at energies around 1 - 10 gev , which could be interpreted in terms of the annihilation of a dm with mass low than about 60 gev into leptons or bottom quarks @xcite . about these experimental results
, it should be noted that they are not completely consistent with each other , and more seriously , they conflict with the xenon data @xcite and the latest lux result @xcite .
so the issue of light dm leaves unresolved and will be a focal point both experimentally and theoretically . on the experimental side , many experiments like lux , xenon , cdms and cdex @xcite will continue their searches , while on the theoretical side we need to examine if such a light dark matter can naturally be predicted in popular new physics theories such as low energy supersymmetry ( susy ) .
previous studies @xcite showed that , in the framework of the next - to - minimal supersymmetric standard model ( nmssm ) @xcite , a light neutralino dm around 10 gev is allowed by the collider constraints and dm relic density ( in contrast such a light dm is not easy to obtain in the mssm @xcite or cmssm @xcite ) . in nmssm , due to the presence of a singlet superfield @xmath2 , we have five neutralinos , three cp - even higgs bosons ( @xmath3 ) and two cp - odd higgs bosons ( @xmath4 ) @xcite .
the mass eigenstates of neutralinos are the mixture of the neutral singlino ( @xmath5 ) , bino ( @xmath6 ) , wino ( @xmath7 ) and higgsinos ( @xmath8 , @xmath9 ) ; while the cp - even ( odd ) higgs mass eigenstates are the mixture of the real ( imaginary ) part of the singlet scalar @xmath10 and the cp - even ( odd ) mssm doublet higgs fields
. an important feature of the nmssm is that the lightest cp - even ( odd ) higgs boson @xmath11 can be singlet - like and very light , and the lightest neutralino ( @xmath12 ) can be singlino - like and also very light . as a result , the spin - independent neutralino - nucleon scattering cross section can be enhanced to reach the cdms - ii value by the @xmath13channel mediation of a light @xmath14 @xcite . meanwhile , the dm relic density can be consistent with the measured value either through the @xmath15channel resonance effect of @xmath11 in dm annihilation or through the annihilation into a pair of light @xmath14 or @xmath16 @xcite .
note that such a light dm in the nmssm should be re - examined because the latest lhc data may give severe constraints .
due to the presence of a light dm and concurrently a light @xmath16 or @xmath14 , the sm - like higgs boson ( @xmath17 ) can have new decays @xmath18 and @xmath19 @xcite . as analyzed in @xcite , such decays may be subject to stringent constraints from the current lhc higgs data @xcite .
besides , since a certain amount of higgsino component in @xmath12 is needed to strengthen the coupling of @xmath20 ( or @xmath21 ) which is necessary for the dm annihilation , the higgsino - dominated neutralinos and the chargino @xmath22 are generally not very heavy and will be constrained by the searches for events with three leptons and missing transverse momentum ( @xmath23 + /@xmath24 ) at 8 tev lhc @xcite . in this work
, we consider these latest lhc data and examine the status of a light dm in the nmssm .
we note that a recent study @xcite tried to explain the cdms - ii results in terms of a light dm in the nmssm .
compared to @xcite which only studied three representative benchmark points , we perform a numerical scan under various experimental constraints and display the allowed parameter space in comparison with the the direct detection results of cogent , cdms - ii and lux .
we also perform a global fit of the higgs data using the package @xcite , in which we further consider the latest lhc results of higgs invisible decay from the channel @xmath25 @xcite .
moreover , we consider the constraints from the searches for events with @xmath23 + /@xmath24 signal at 8 tev lhc @xcite .
the paper is organized as follows .
in sec.ii we list the experimental constraints and describe our scan .
in sect.iii we present our results and perform detailed analysis . finally , we draw our conclusions in sec.iv .
in order to reduce the number of free parameters in our scan over the nmssm parameter space , we make some assumptions on the parameters that do not influence dm properties significantly . explicitly speaking , we fix gluino mass and all the soft mass parameters in squark sector at 2 tev , and those in slepton sector at 300 gev .
we also assume the soft trilinear couplings @xmath26 and let them vary to tune the higgs mass . moreover , in order to predict a bino - like light dm and also to avoid the constraints from @xmath27 invisible decay @xcite , we abandon the gut relation between @xmath28 and @xmath29 .
the free parameters are then @xmath30 in the higgs sector , the gaugino and higgsino mass parameters @xmath31 and @xmath32 , and the soft trilinear couplings of the third generation squarks @xmath33 . in this work , we define all these parameters at @xmath34 scale and adopt the markov chain monte carlo ( mcmc ) method to scan the following parameter ranges using @xmath35 @xcite : @xmath36 note here that the ranges of @xmath37 and @xmath38 are motivated to avoid landau pole , generally corresponding to the requirement of @xmath39 .
this has been encoded in @xmath35 including the consideration of the interplay between @xmath37 and @xmath38 in the renormalization group running .
a relatively small @xmath32 is chosen to avoid strong cancelation in getting the @xmath27 boson mass @xcite , and as we will see below , the upper bound of @xmath40 for @xmath32 here suffices our study and does not affect our main conclusions .
also note that we artificially impose a lower bound of 320 gev for @xmath29 .
this is motivated by the fact that @xmath29 in our study is not an important parameter , and that as required by the @xmath23 + /@xmath24
constraint @xmath29 should be larger than about 320 gev in the simplified model discussed in @xcite ( also see the constraint ( viii ) discussed below ) .
the relevant @xmath41 function for the mcmc scan is build to guarantee the dm relic density and the sm - like higgs boson mass around their measured values . in our discussion , we consider the samples surviving the following constraints : * @xmath42 and @xmath43 .
* _ the constraints from b - physics_. the light cp - even / odd higgs bosons can significantly affect the b - physics observables .
especially , the precise measurements of radiative decays @xmath44 @xcite , @xmath45 @xcite and @xmath46 @xcite can give stringent constraints .
so we require the samples to satisfy these b - physics bounds at 2@xmath47 level . *
_ dm relic density_. as the sole dark matter candidate , the lightest neutralino @xmath12 is required to produce the correct thermal relic density .
we require the neutralino relic density to be in the @xmath48 range of the planck and wmap 9-year data , @xmath49 , where a 10% theoretical uncertainty is included @xcite .
* _ muon g-2_. we require nmssm to explain the muon anomalous magnetic moment data @xmath50 @xcite at @xmath48 level . * _ the absence of landau pole_. we impose this constraint using @xmath35 @xcite , where the interplay of @xmath37 and @xmath38 in the renormalization group running has been considered . *
_ lep searches for susy_. for the lep experiments , the strongest constraints come from the chargino mass and the invisible @xmath27 decay .
we require @xmath51 and the non - sm invisible decay width of @xmath52 to be smaller than 1.71 mev , which is consistent with the precision electroweak measurement result @xmath53 mev at @xmath54 confidence level @xcite . * _ higgs data_. firstly , we consider the exclusion limits of the lep , tevatron and lhc in higgs searches with the package @xcite .
this package also takes into account the results of the lhc searches for non - sm higgs bosons , such as @xmath55 and @xmath56 @xcite . secondly ,
noticing that a light @xmath14 ( or @xmath16 ) may induce the distinguished signal @xmath57 , we consider the limitation of the @xmath58 signal on the parameter space using the latest cms results @xcite .
finally , since a large invisible branching ratio of the higgs may be predicted in the light dm case , we perform a global fit of the higgs data using the package @xcite , where the systematics and correlations for the signal rate predictions , luminosity and higgs mass predictions are taken into account . in our fit , we further consider the latest lhc results of higgs invisible decay from the channel @xmath25 @xcite .
we require our samples to be consistent with the higgs data at @xmath48 level , which corresponds to @xmath59 with @xmath41 obtained with the and @xmath60 denoting the minimum value of @xmath41 for the surviving samples in our scan .
* _ lhc searches for susy_. based on the 20 fb@xmath61 data collected at the 8 tev run , the atlas and cms collaborations performed a search for the @xmath62 production with @xmath23 + /@xmath24
signal in a simplified model , where both @xmath63 and @xmath64 are assumed to be wino - like with @xmath65 , and a 95% c.l .
upper limit on @xmath66 was obtained on the @xmath67 plane @xcite .
+ in this work , in order to implement this constraint we perform an analysis similar to @xcite with the code checkmate @xcite for each sample surviving the constraints ( i ) - ( vii ) .
we consider the contributions from all @xmath68 ( @xmath69 and @xmath70 ) associated production processes to the signal , and calculate the production rates and the branching ratios with the code prospino2 @xcite and nmsdecay @xcite , respectively .
our analysis indicates that this constraint can exclude effectively those samples with small values of @xmath32 below 115 gev , and also some samples with moderate @xmath32 in the range from 115 gev to 200 gev .
nevertheless , compared to the results without considering this constraint , our conclusions do not change much such as the upper bounds on @xmath71 presented below . in order to study the implication of the dm direct detection experiments on the nmssm
, we also calculate the dm spin - independent elastic scattering cross section off nucleon with the formulae used in our previous work @xcite . in getting the cross section
, we set the parameter of the strange quark content in the nucleon as @xmath72 .
in the rest of this work , we categorize the dm by its component , i.e. either bino - like or singlino - like , in presenting our results .
since the interactions of the neutralinos with the higgs bosons come from the following lagrangian @xmath73 where the fields @xmath74 , @xmath75 and @xmath76 denote the neutral scalar parts of the higgs superfields @xmath2 , @xmath77 and @xmath78 , respectively , one can infer that if the dm is bino - like , the coupling strength of the @xmath79 interaction is mainly determined by the higgsino - component in @xmath80 , or more basically by the value of @xmath32 . to be more specific ,
if @xmath81 is sm - like , the coupling strength is mainly determined by the first two terms in the second row of eq.[interaction ] , while if @xmath81 is singlet - dominated , the coupling of @xmath79 is mainly determined by the first term of eq.[interaction ] . however ,
if the dm is singlino - like , the coupling strength is fundamentally determined by the parameters @xmath37 and @xmath38 and a low @xmath32 value may be helpful to enhance the coupling . in this work , we are also interested in the couplings of the sm - like higgs to light singlet - like scalars @xmath14 and @xmath16 .
these couplings are mainly determined by the following terms in the higgs potential @xcite @xmath82 this equation indicates that , if @xmath37 and @xmath38 approach zero , the couplings @xmath83 can not be very large ; while if both of them have a moderate value , accidental cancelation is very essential to suppress the couplings .
in fig.[fig1 ] we project the samples surviving the above constraints on the plane of neutralino dark matter mass versus spin - independent neutralino - nucleon scattering cross section . about this figure , we want to emphasize two points .
the first one is that some of the experimental constraints , such as the dm relic density and the higgs data , play an important role in limiting the parameter space of the nmssm .
so in the following , we pay special attention to investigate how the samples in fig.[fig1 ] survive these constraints .
the other one is that the various experimental constraints will cut into the parameter space and the interplay among them is very complicated . as a result , the sample distributions on the @xmath84 plane might be very wired .
the strategy of analyzing this figure is to get a general picture of the current status of light dm confronting the direct detection results and then focus on some interesting regions . as we will discuss later
, we will mainly focus on those samples that either can explain the cdms - ii results or can survive the first lux exclusion .
we will not consider the up - right region ( @xmath85 ) in fig.[fig1 ] since it is not experimentally hinted .
after carefully analyzing our results , we have the following observations from fig.[fig1 ] : 1 . in the nmssm ,
dm as light as @xmath86 is still allowed by the current higgs data .
both the bino and singlino - like dm are capable of explaining the results of cdms - ii and cogent , or surviving the current lux results and future lux exclusion limits .
2 . as pointed out in @xcite , light dm in the nmssm may annihilate in the early universe through @xmath74-channel resonance effect of some mediators or into light higgs scalar pair to get a correct relic density .
we checked that , for @xmath87 , singlino - like dm annihilated in the early universe mainly through the @xmath74-channel resonance effect of @xmath88 for the most case ; while bino - like dm might annihilate either through the resonance effect or into @xmath14 ( @xmath16 ) pair .
we will discuss this issue in more detail later .
+ in fact , the long thick band of grey samples ( for bino - like dm ) around @xmath89 exactly corresponds to the resonance case , and samples along this band are characterized by @xmath90 with @xmath91 denoting the mediator mass . for @xmath92 and @xmath93 ,
the mediator is @xmath27 boson and the sm - like higgs boson , respectively , while in other cases the mediator is either @xmath14 or @xmath16 .
these conclusions can also apply to the singlino - like dm ( see fig.[fig2 ] ) .
3 . for samples with @xmath94 ,
generally @xmath14 needs to be lighter than about @xmath95 to push up the scattering rate . for the bino - like dm with mass varying from @xmath96 to @xmath97 ,
such a light @xmath14 is difficult to obtain after considering the constraint from the relic density ( see fig.[fig2 ] ) .
while in the @xmath27 ( @xmath17 ) resonance region , the relic density has rather weak limitation on @xmath14 properties . in this case , @xmath14 may be as light as several gev so that the scattering rate is rather large , or the coupling @xmath98 may be greatly reduced to result in a relatively small @xmath99 .
4 . for bino - like dm ,
generally it is not easy to obtain samples with @xmath100 .
this is because the @xmath101 interaction is still sizable even after considering the various constraints ( see discussions on fig.[fig3 ] ) , and in this case , the @xmath17-mediated contribution to the dm - nucleon scattering is important .
however , in the extreme case when the bino - like dm is close to about @xmath102 , due to the lower bound of @xmath32 , the higgsino component in the dm will get further reduced and result in an even smaller @xmath103 .
5 . when focusing on the xenon and lux experiments , the bino - like and singlino - like dm exhibit quite different behaviors .
the first lux-300 kg result can exclude a large part of the allowed parameter space , but still leaves both the bino - like and singlino - like light dm viable .
the future xenon-1 t and lux-7.2ton results can cut further deeply into the parameter space .
especially , they limit tightly the bino - like dm case and constrain most of the bino - like dm mass to be lower than about 17 gev and 12 gev , respectively , while the singlino - like dm can still survive leisurely .
6 . for bino - like dm samples
there is a gap in the right half part of the cdms - ii @xmath48 region .
this is due to the tension between the lhc higgs data and the constraint from @xmath104 . as discussed in @xcite ( and see table i ) , the cdms - ii favored samples in bino - like dm scenario usually require a moderate @xmath37 along with a moderate @xmath38 to achieve the accidental cancelation in @xmath105 so that the sm - like higgs decay to @xmath14 or @xmath16 pair is suppressed . while on the other hand , this may increase the effective coupling of @xmath14 to down - type fermions which is proportional to @xmath106 with @xmath107 $ ] @xcite , and receive constraint from the measurement of @xmath104 .
we checked that most of the excluded bino - like dm samples in the gap have a relatively large @xmath37 , while the singlino - like dm samples usually correspond to a small @xmath37 ( see following discussion on table i ) and thus receive less constraint .
compared to bino - like dm which is restricted in certain areas on the @xmath84 plane , singlino - like dm can spread nearly to the whole region of the plane .
this reflects the fact that singlino - like dm is more adaptable in light dm physics .
.the ranges of relevant nmssm input parameters corresponding to part of the samples in fig.1 , which predict a dm lighter than 35 gev and meanwhile can explain the cdms - ii at 2@xmath47 level or survive the lux-300 kg exclusion limit .
parameters with the mass dimension are in the unit of gev .
[ cols="^ , < , < , < , < " , ] in the following , we concentrate on the samples in fig.1 that can either explain the cdms - ii experiment at @xmath48 level or survive the lux-300 kg exclusion limit
. since the results of the cdms - ii and lux experiments are so incompatible , it would be interesting to investigate the difference of these two types of samples .
to simply our analysis , we mainly consider the samples predicting a dm lighter than about 35 gev .
these samples are not easy to obtain with traditional random scan method when exploring the susy parameter space due to its rather specific particle spectrum , but as we will see below , the underlying physics of these samples are clear and easy to understood . in table
[ table1 ] , we list the ranges of relevant nmssm input parameters corresponding to these samples , which are classified by the component of the dm ( i.e. bino - like or singlino - like ) and meanwhile by its scattering cross section off the nucleon ( i.e. can explain the cdms - ii results at @xmath48 level or survive the lux-300 kg exclusion limit ) . from table
i , one can learn the following facts : * the survived parameter ranges for lux - safe samples are generally wider than those of cdms - ii preferred samples .
this is totally expectable from the experimental data of lux and cdms - ii . on the @xmath84 plane , cdms - ii @xmath48 region
is constrained in a relatively narrow range @xmath108 and @xmath109 . to survive the first lux exclusion
, however , a properly large @xmath110 for a certain @xmath111 will be enough .
@xmath111 can cover the whole range @xmath112 and @xmath99 can vary from @xmath113 to @xmath114 .
therefore , compared to cdms - ii region , there will be more freedom for the parameter space to satisfy the lux exclusion . * to obtain a dm lighter than 35 gev , one needs to have @xmath115 for the bino - like dm and @xmath116 for the singlino - like dm .
this can be easily understood from the neutralino mass matrix @xcite .
@xmath117 where @xmath118 and @xmath119 are gauge couplings , and @xmath120 and @xmath121 are higgs vacuum expectation values .
in fact , a simple estimation can be made for singlino - like dm mass .
table [ table1 ] shows that @xmath122 is usually at least one order smaller than @xmath37 .
assuming @xmath123 and @xmath124 , we will have @xmath125 .
* the cdms - ii samples usually have @xmath126 for both bino - like and singlino - like dm .
the underlying reason is that a small value of @xmath32 and consequently a sufficient amount of higgsino component in the dm is helpful to increase the coupling strength of the dm with the light higgs bosons .
this will in return push up the rate of the dm - nucleon scattering which is required by the cdms - ii results . *
more interestingly , we find that for samples in the whole range of @xmath127 , the value of @xmath32 is upper bounded by about @xmath128 and @xmath129 for bino - like and singlino - like dm , respectively .
two reasons can account for this .
the first one is that in our scan , we required the nmssm to explain the muon anomalous magnetic moment .
the parameter @xmath32 influences the contribution of the nmssm to the moment through chargino and neutralino mass , and a large value of @xmath32 will reduce the contribution significantly .
another important reason is that , as mentioned above and also discussed below , in order to get a correct dm relic density , a light @xmath14 or @xmath16 must be present .
noting that @xmath32 enters explicitly the squared mass of the singlet scalar @xcite , one can infer that too large values of @xmath32 can not be favored to get the desired light scalar masses .
+ we also want to emphasize that , for the bino - like dm , an upper bound of @xmath32 will result in a lower limit of the higgsino component in the dm and thus a lower bound of the invisible branching ratio for @xmath130 .
this can be explicitly seen in the left panel of fig.[fig3 ] below . * for singlino - like dm case , both @xmath37 and @xmath38 are small and especially , @xmath122 is very close to 0 .
as indicated by eqs.([interaction],[higgs_potential],[neutralino_mass_matrix ] ) , the couplings of sm - like higgs boson to dm and also to the light higgs scalars @xmath131 will usually be suppressed .
this can result in a @xmath99 as low as @xmath132 ( see fig.[fig1 ] ) and also a relatively small rate for the decays @xmath133 ( see fig.[fig3 ] and fig.[fig4 ] ) . while for the bino - like dm case with a moderate value of @xmath37 and @xmath38 , accidental cancelation is very essential to suppress the couplings of @xmath17 to @xmath134 and obtain an allowed higgs signal . as discussed in fig.[fig1 ] , given @xmath135 , at least one light scalar is needed to accelerate the annihilation . in order to illustrate this feature , in fig.[fig2 ] we project the @xmath135 samples of fig.1 which can explain the cdms - ii results at 2@xmath47 level or survive the lux-300 kg exclusion limits on the plane of dm mass versus @xmath136 .
red codes represent samples suggested by the cdms - ii experiment and meanwhile satisfying @xmath137 , while cyan ( blue ) codes correspond to samples surviving the lux-300 kg exclusion limits and also satisfying @xmath137 ( @xmath138 ) .
note that due to the large scattering cross section favored by the cdms - ii results , a light @xmath14 is needed ( as the t - channel propagator ) and the case @xmath139 is absent . from fig.[fig2 ] we have the following observations : samples in fig.[fig1 ] which can explain the cdms - ii results at 2@xmath47 level or survive the lux-300 kg exclusion limits , projected on the plane of dm mass versus @xmath136 .
red codes represent samples suggested by the cdms - ii experiment and meanwhile satisfying @xmath137 , while cyan(blue ) codes correspond to samples surviving the lux-300 kg exclusion limits and also satisfying @xmath137 ( @xmath138 ) .
note that due to the large scattering cross section favored by the cdms - ii results , a light @xmath14 is needed ( as the t - channel propagator ) and the case @xmath139 is absent.,width=604 ] 1 . in both bino - like and singlino - like dm scenario ,
the straight line @xmath140 is very obvious , which corresponds to the s - channel resonance effect of @xmath14 or @xmath16 .
however , in the singlino - like scenario with @xmath141 , there are some small regions where the line seems to be not continuous .
in fact , this is not the case .
we checked that there still exits a scalar ( either @xmath14 or @xmath16 ) with mass around @xmath142 .
it is just that this scalar does not correspond to the lightest higgs boson .
moreover , for the scalars shown in fig.[fig2 ] , we checked that they are highly singlet - dominated , which agree with previous study in @xcite .
2 . since @xmath14 contributes to the spin - independent dm - nucleon scattering as the t - channel propagator @xcite , a very light @xmath14 is needed to explain the cdms - ii result . for the bino - like dm ,
the cdms - ii samples are mainly distributed in low @xmath143 region with @xmath110 upper bounded by about 4 gev , while for the singlino - like dm , the corresponding samples spread a larger region in @xmath144 plane .
moreover , when focusing on the cdms - ii samples , we checked that if the dm is bino - like , the channel @xmath145 plays the dominant role in contributing to the dm annihilation , while if the dm is singlino - like , the s - channel resonance effect is the main contribution .
since the constraint from the lux-300 kg data on the scattering rate is rather weak in the very light dm region , @xmath14 as light as 1 gev is still allowed for @xmath146 . with the increase of dm mass ,
the constraint becomes much stronger and @xmath14 generally needs to be heavier than about 10 gev for @xmath147 in both scenarios . , but projected on the plane of the invisible branching fractions of the sm - like higgs boson versus dm mass , and extended the dm mass to about 60 gev.,width=604 ] for the sm - like higgs boson , since the decay channel @xmath148 is opened when @xmath149 , one can expect that the higgs data will impose rather tight constraints on this decay rate . in fig.[fig3 ] , we show the samples of fig.[fig2 ] on the plane of @xmath150 versus dm mass and extend the dm mass to about 60 gev .
we have the following observations : 1 .
the current higgs data still allow for an invisible decay branching ratio as large as @xmath0 at @xmath48 level .
the tolerance of such a large invisible branching ratio is owe to the large uncertainties of the current data , especially the fact that atlas and cms data point to two opposite directions in the di - photon rate .
obviously , an invisible decay branching ratio reaching @xmath0 may be easily tested at the 14 tev lhc with @xmath151 fb@xmath61 , where a 95% c.l .
upper limit on the invisible decay , i.e. @xmath152 , can be imposed @xcite .
2 . in the bino - like dm scenario , due to the necessary higgsino component in the dm required by an efficient dm annihilation rate , the interaction between dm and @xmath17 can be relatively large . as a result , @xmath150 as large as @xmath0 is possible .
note that for the cdms - ii samples , @xmath150 is always larger than about @xmath153 .
the underlying reason is that , as we mentioned earlier , the channel @xmath145 plays an important role in contributing to the dm annihilation .
this requires the strength of the @xmath154 interaction to be sufficiently large , and so is the @xmath155 interaction .
also note that since @xmath32 is upper bounded for @xmath156 ( see table [ table1 ] ) , generally there is a lower bound of @xmath157 .
3 . in the singlino - like scenario ,
since the @xmath158 coupling is determined by @xmath37 and @xmath38 and table [ table1 ] indicates that these two parameters are generally small , @xmath150 is usually suppressed and can reach about @xmath159 in the optimal case . , but showing the branching fraction of decays @xmath160 versus dm mass.,width=604 ] due to the existence of light scalars in light dm scenario , the sm - like higgs may also decay into the lighter scalars , @xmath161 . unlike the @xmath162 coupling , the coupling strengthes of @xmath17 to these scalars are mainly determined by @xmath37 and @xmath38 ( see eq.([higgs_potential ] ) and also note that both @xmath14 and @xmath16 are highly singlet - dominated @xcite ) . consequently , according to table [ table1 ] , the maximum decay rate in the bino - like dm scenario should in principle be larger than that in the singlino - like case . similar to fig.[fig3
] , we show the total branching fractions of these two decays versus dm mass in fig.[fig4 ] . one can learn that this branching ratio can reach @xmath0 in the bino - like dm scenario , while in the singlino - like case the maximum can only reach about @xmath159 .
under current experimental constraints including the latest lhc higgs data and the dark matter relic density , we examined the status of a light nmssm dark matter and confronted it with the direct detection results of cogent , cdms - ii and lux .
we have the following observations : ( i ) a dark matter as light as 8 gev is still allowed and its scattering cross section off the nucleon can be large enough to explain the cogent / cdms - ii favored region ; ( ii ) the lux data can exclude a sizable part of the allowed parameter space , but still leaves a light dark matter viable ; ( iii ) the sm - like higgs boson can decay into the light dark matter pair and its branching ratio can reach @xmath0 at @xmath48 level under the current lhc higgs data , which may be covered largely at the 14 tev lhc experiment .
we thank nima arkani - hamed , archil kobakhidze , yang zhang and jie ren for helpful discussions .
this work was supported by the arc center of excellence for particle physics at the tera - scale , by the national natural science foundation of china ( nnsfc ) under grant no .
10821504 , 11222548 , 11305049 and 11135003 , and also by program for new century excellent talents in university .
s. schael _ et al . _
[ aleph and delphi and l3 and opal and sld and lep electroweak working group and sld electroweak group and sld heavy flavour group collaborations ] , phys . rept . * 427 * , 257 ( 2006 ) [ hep - ex/0509008 ] . | in susy , a light dark matter is usually accompanied by light scalars to achieve the correct relic density , which opens new decay channels of the sm - like higgs boson . under current experimental constraints including the latest lhc higgs data and the dark matter relic density
, we examine the status of a light neutralino dark matter in the framework of nmssm and confront it with the direct detection results of cogent , cdms - ii and lux .
we have the following observations : ( i ) a dark matter as light as 8 gev is still allowed and its scattering cross section off the nucleon can be large enough to explain the cogent / cdms - ii favored region ; ( ii ) the lux data can exclude a sizable part of the allowed parameter space , but still leaves a light dark matter viable ; ( iii ) the sm - like higgs boson can decay into the light dark matter pair with an invisible branching ratio reaching @xmath0 under the current lhc higgs data , which may be tested at the 14 tev lhc experiment . |
there is rapidly growing evidence for smbhs in the centers of many galaxies ( for a review see @xcite ) .
there are too many examples to list here ; indeed , there are only a few galaxies for which observations indicate that a central smbh does not exist@xcite .
many authors have pointed out that the mass of the central black hole @xmath2 correlates linearly with the mass of bulge @xmath3 , _
i.e. _ , the ratio of @xmath2 to @xmath3 is almost constant ( 0.002 @xcite to 0.006@xcite ) .
this suggests that the formation of the central bh is somehow related to the formation of the bulge .
the formation mechanism of smbhs is not well understood .
our theoretical understanding has not advanced much beyond the scenarios described by rees@xcite in the early 1980s . in the famous diagram by rees ,
there were basically two paths from gas clouds to massive black holes .
the first is direct monolithic collapse , the second is via the formation of a star cluster , with subsequent runaway collisions leading to bh formation .
previous numerical studies , however , have demonstrated that neither path is likely . in the first , a massive gas cloud is more likely to fragment into many small clumps , in which stars then form , so direct formation of a massive bh from a gas cloud seems unlikely . in the second , stellar dynamics in star clusters
does not easily lead to the formation of massive black holes .
a number of low - mass black holes ( masses around 10m@xmath1 ) are formed via the evolution of massive stars , and these black holes do indeed sink to the center of the cluster through dynamical friction and form binaries by three - body encounters .
however , recent @xmath4-body simulations@xcite have demonstrated that practically all of these black - hole binaries are ejected from the cluster by recoil following interactions with other black holes ( or bh binaries ) before they can merge through gravitational radiation .
@xcite have identified nine bright compact x - ray sources in the central region of m82 using recent chandra data .
the brightest source ( no . 7 in their table 1 )
had a luminosity of @xmath5 in jan 2000 , corresponding to a black hole with a minimum mass of @xmath6 ( assuming emission at the eddington limit ) .
it probably consists of a single compact object , as its x - ray flux shows rapid time variation@xcite .
this is the first detection of a bh with a mass much greater than @xmath7 but much less than @xmath8 . among the eight other sources , at least three ( 5 , 8 and 9 ) have eddington masses greater than @xmath9 .
@xcite observed the same region in using nobeyama millimeter array and found a huge expanding shell of the molecular gas .
they estimated the age and kinetic energy of the shell to be around 10 myr and @xmath10 erg , which suggest a strong starburst took place a few myrs ago .
@xcite observed the same region in the ir ( j , h , and k@xmath11-band ) using the cisco instrument on the subaru telescope@xcite .
they identified a number of young compact star clusters , at least four of them coinciding with the x - ray sources within the position uncertainty of chandra and subaru .
the subaru field of view is smaller than that of chandra , and three of the x - ray sources are outside of the ir field .
thus , four out of six bright x - ray sources in the ir field of view have been identified with bright star clusters .
the logical conclusion from these observations is that most of chandra x - ray sources , including the brightest one with an eddington mass of @xmath12 , are formed in star clusters .
therefore , we now have two important observational results .
the first is that a bh with intermediate mass ( @xmath13 ) has been found .
the second is that it coincides with a young compact star cluster . in the following ,
we discuss how these findings change our understanding of the formation of supermassive bhs .
we first discuss how imbhs can be formed in young compact star clusters , then how imbhs might grow into smbhs .
here we consider some formation mechanisms for imbhs in star clusters ( see figure 1 ) . an obvious way to form an imbh is the collapse of a supermassive star .
however , this possibility seems to have little observational or theoretical support .
observationally , no stars with masses larger than @xmath14 are known .
the most luminous star currently known is the pistol star@xcite , with an estimated present mass of less than @xmath15 .
recent radio observations of this star have detected signs of a strong stellar wind@xcite , which is consistent with the theoretical prediction that such massive stars are dynamically unstable@xcite .
we therefore regard it as unlikely that an imbh with mass exceeding @xmath6 could have formed by the collapse of a single massive star .
an alternative possibility is the formation and growth of massive stars ( and imbhs ) through successive merging .
massive stars in star clusters have higher merger rates than less massive cluster members ( or field stars ) , for the following three reasons .
first , they have larger geometrical cross sections , and these are further enhanced by gravitational focusing .
second , because of mass segregation , these stars tend to be found in the high - density region near the cluster center .
third , the most massive stars at the center tend to form binaries through three - body interactions , and binary membership greatly increases their chances of merging .
a significant fraction of binary - single star encounters lead to complex resonances during which very close encounters can occur .
many such encounters lead to physical collisions between stars @xcite .
if these effects are strong enough , we expect that a `` merging instability''@xcite , or a runaway growth of the most massive star , will occur in the cluster core .
@xcite performed fokker - planck simulations of globular clusters with merging of stars taken into account .
he included the first two of the three effects mentioned above , and concluded that the merger instability is unlikely unless the mass of the globular cluster is very large ( @xmath16 , where @xmath4 is the number of stars ) .
recently , however , @xmath4-body simulations carried out by @xcite have demonstrated that runaway merging can take place in much smaller systems containing only @xmath17 stars .
the primary reason for this discrepancy is that , in @xmath4-body simulations , all three of the effects described above are automatically included , whereas in the fokker - plank calculation by lee the third was not modeled .
a second reason is that portegies zwart et al . considered a young , compact cluster , similar to r136 in the lmc or the arches and quintuplet systems in the galactic center , while lee considered normal globular clusters
thus , the dynamical timescale was much shorter in the models considered by portegies zwart et al . , allowing merging to occur before stellar evolution eliminated the most massive stars .
portegies zwart et al
. found that , in one case , the most massive star experienced more than ten collisions and reached a mass of around @xmath18 before experiencing a supernova . there is considerable uncertainty as to how much mass would remain as a bh after the supernova explosion of such a massive star , but it is quite likely that the remnant black hole would still be one of the most massive objects in the cluster , and that the runaway merging process would continue .
although the geometrical cross section of a bh is small , `` merging '' would take place when a star approached within its tidal radius , leading to a relatively large merger cross section . in order for runaway merging to occur , the dynamical friction timescale for the most massive stars must be short enough that they can sink to the center during their lifetime of several myr .
the dynamical friction timescale may be expressed as@xcite : @xmath19 where @xmath20 is the coulomb logarithm , @xmath21 is the gravitational constant , @xmath22 is the local velocity dispersion , @xmath23 is the distance from the center of the cluster , @xmath24 and @xmath25 are the half - mass radius and the total mass of the cluster , and @xmath26 is the mass of the star . in the following ,
we consider how the dynamical friction works in the cluster found in m82 . from the infrared luminosity , @xcite estimate that the total mass of the cluster is @xmath27 .
they also estimated the seeing - corrected radius of the cluster as 5 pc .
the dynamical friction timescale is around 800 myr for stars at the half mass radius of the cluster .
this looks too long , but in fact it is not .
as can be seen from equation ( [ eq : df ] ) , the timescale depends rather strongly on @xmath23 . for @xmath28 , a volume which still contains about 5% of the total cluster mass ,
the dynamical friction timescale is less than 10 myr .
we therefore conclude that there is time for a fair fraction of the most massive stars in the cluster to sink to the cluster center and undergo runaway merging before exploding as supernovae .
after the bh has become much more massive than other cluster members , it forms a cusp near the cluster center @xcite , and continues to consume other stars .
unfortunately , no realistic simulations of this phase of the evolution are available .
@xcite performed monte - carlo simulations of this stage for a simplified cluster containing @xmath29 solar - mass stars and one 50 solar - mass seed bh .
they found that the bh mass jumped to over @xmath30 ( 0.3% of the cluster mass ) almost immediately after they put the bh into the system .
after this initial rapid growth , a slower phase ensued , with a doubling timescale comparable to the relaxation time of the cluster . their result should be regarded as a lower limit on the bh growth rate , since realistic effects , in particular the presence of a mass spectrum , would greatly enhance the accretion rate . taking these effects into account
, it seems safe ( even conservative ) to suppose that 0.1% of the total cluster mass accretes to form a @xmath31 central bh in a few myr .
as stated above , there are more than 10 bright star clusters in the vicinity of the imbh host cluster in m82 , some of them apparently hosting small bhs .
their age is around 10 myr@xcite .
also , the starburst in m82 is a long - duration event , having started at least 200 myr ago@xcite .
if we assume that the clusters are formed in a constant rate , we would conclude that around 200 clusters have been formed .
the star formation rate certainly has not been constant , so there is considerable uncertainty in our estimate .
even so , we believe it is safe to assume that around one hundred clusters similar to our host cluster have formed in total , and that a considerable fraction of them host imbhs .
yr ) , those stars sink to the cluster core by dynamical friction , and form a dense inner core of massive stars at the cluster center . in this inner core ,
the massive stars undergo runaway stellar merging and a very massive star with mass exceeding 100 @xmath32 forms .
this massive star eventually collapse into a black hole , which continues to grow by swallowing nearby massive stars .
if the cluster is not dense enough for mass segregation to occur in 10 myr , massive stars evolve into compact stellar remnants such as neutron stars and stellar - mass black holes ( @xmath33 ) .
those stellar remnants slowly sink to the cluster center , since they are heavier than other stars in the system , and eventually form binaries .
successive three - body interactions made these binaries more tightly bound , and eventually they are ejected from the cluster by slingshot mechanism . ,
the growth rate of the imbh in a star cluster slows once massive stars disappear ( after @xmath34 myr ) .
what happens to the cluster and the imbh after the initial rapid growth phase ? in the discussion below , we assume a cluster mass of @xmath35 m@xmath1 and a half - mass radius of 5pc .
the cluster is subject to two evolutionary processes : evaporation through two - body relaxation and orbital decay ( sinking ) via dynamical friction .
evaporation is driven partly by thermal relaxation and partly by stellar mass loss .
@xcite estimated that the evaporation timescale for a roche - lobe - filling compact star cluster is around 2 - 3 half - mass relaxation times , which is of the order of a few gyr for our star clusters . rewriting equation ( [ eq : df ] ) using appropriate scaling for this case
, we find that timescale on which the cluster sinks to the galactic center via dynamical friction is @xmath36 clusters initially within 1 kpc of the galactic center can therefore reach the center within one gyr .
note that an imbh can reach the galactic center only if its host cluster can sink to the center before it evaporates .
if the cluster dissolves before significant orbital decay occurs , the timescale for the imbh to fall to the center increases greatly .
according to our estimate in the previous section , around 100 compact clusters have formed close to the center of m82 in the last 200 myrs .
if we assume that half of these clusters contain @xmath37 imbhs , and that these imbhs actually merge , then the total bh mass at the center of the galaxy would be at least @xmath38 , high enough to be called a supermassive bh , if we take into account the relatively small total mass of m82 .
having demonstrated that @xmath39 imbhs can form and reach the galactic center in a reasonable timescale , we now turn to the question of whether the multiple imbhs at the center can merge .
@xcite discussed the evolution of a supermassive bh binary at the center of a galaxy , taking into account dynamical friction from field stars and energy loss via gravitational radiation .
they found that the merging timescale depends strongly on mass , and for the very massive bhs in which they were interested , merging took much longer than a hubble time .
there are two reasons why they obtained such a long timescale .
the first is that they considered smbhs with masses exceeding @xmath40 , and the timescale for orbital decay via gravitational radiation is proportional to the mass , for given orbital velocity .
the second reason is that they assumed that `` loss - cone depletion '' would occur . in other words
, they assumed that stars approaching close enough to the bh binary to interact were supplied only though two - body relaxation , which is a very slow process in large elliptical galaxies .
however , for the imbhs we consider here , the timescale for merging through gravitational radiation is many orders of magnitude shorter than that for the smbhs considered by begelman et al .
one reason is simply that the imbh mass is many orders of magnitude smaller .
an imbh of mass @xmath41 has a timescale @xmath42 times shorter than a @xmath43 smbh when compared at the same orbital velocity .
a second reason is that loss - cone depletion is not as effective as originally assumed , at least for relatively small bh mass
. therefore imbhs can reach high orbital velocities in short timescales .
recent extensive numerical simulations @xcite have shown that the hardening of the bh binary through dynamical friction is in fact several orders of magnitude faster than the prediction from loss - cone arguments .
a third reason for the long smbh merger time is the fact that begelman et al .
ignored the effects of eccentricity , which can significantly reduce the merging time scale .
thus , we can safely conclude that the merging time scale for imbhs with masses less than @xmath44 is no more than a few myr .
since we expect many imbhs to fall to the center of the galaxy on a timescale of 100 myr , in principle , slingshot ejection might remove some of them from the region .
however , once one bh has become more massive than typical infalling bhs , it becomes extremely unlikely that it will be ejected , since the kick velocity is inversely proportional to the mass ( because of momentum conservation ) .
thus , even though some of the infalling bhs might be ejected , the central bh would continue to grow .
figure 2 summarizes the discussion in this section .
in this paper , we have discussed the implications for our understanding of the smbh formation mechanism of the recent discovery of an imbh in m82 .
our conclusion is that the imbh found in m82 plays the role of `` missing link '' between stellar - mass bhs and smbhs .
since we now know that imbhs exist , it seems natural to expect that smbhs might be formed from them .
we propose that imbhs are formed in the cores of young compact star clusters through merging of massive stars and bhs formed from them .
these compact young clusters sink to the galactic center by dynamical friction . at the same time , they evaporate via thermal relaxation , stellar mass loss and the effect of the parent galaxy s tidal field .
thus , imbhs are created and transported to the center of the galaxy , where they eventually merge to form smbhs . in the following ,
we discuss how we might seek to confirm our new scenario . the most direct evidence would be the observation of gravitational radiation from close binary imbhs or merging imbhs .
lisa @xcite , when completed , will be able to detect imbh merging events even at cosmological distances .
the event rate for merging of smbh is estimated to be one per 110 years . in our scenario , each smbh is a product of @xmath34 mergings of imbhs or imbh and growing smbh .
therefore we predict a much higher event rate for imbh - imbh and imbh - smbh merging , of the order of 1 per month or even 1 per week
. to test our hypothesis , searches for imbhs in other galaxies are clearly necessary . in our view , imbhs are likely to form in young compact star clusters created in nuclear starbursts .
we predict that coordinated observations of nearby starburst galaxies at ir , x - ray and radio wavelengths , like those performed for m82 , will reveal many more candidate imbhs .
it is also vital to determine internal and external kinematics of the host star clusters of imbhs .
high - dispersion spectroscopy in the ir with large ground - based telescopes such as subaru should be able to determine the velocity dispersion of such a star cluster .
observations by hst would easily resolve the cluster and give us detailed information of its structure .
comparison of these results with theoretical models will then determine whether or not runaway merging can actually take place there .
the ultra luminous compact x - ray sources@xcite may be directly related to imbhs .
these are luminous compact x - ray sources with eddington masses exceeding 100 @xmath45 .
most are found in the arms of spiral galaxies .
thus , they are probably related to young star clusters , and might well also have been formed through merging of massive stars .
their relatively low masses may reflect the differences sizes and masses of their parent star clusters .
this work was supported in part by nasa through hubble fellowship grant hf-01112.01 - 98a awarded by the space telescope science institute , which is operated by the association of universities for research in astronomy , inc .
, for nasa under contract nas 5 - 26555 and by the research for the future program of japan society for the promotion of science ( jsps - rftp97p01102 ) . slwm and spz acknowledge support of nasa atp grants nag5 - 6964 and nag5 - 9264 .
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rees , m. j. , 1984 , 22 , 471 . | observations of stellar kinematics , gas dynamics and masers around galactic nuclei have now firmly established that many galaxies host central supermassive black holes ( smbhs ) with masses in the range @xmath0m@xmath1 .
however , how these smbhs formed is not well understood .
one reason for this situation is the lack of observations of intermediate - mass bhs ( imbhs ) , which could bridge the gap between stellar - mass bhs and smbhs .
recently , this missing link ( i.e. , an imbh ) has been found in observations made by the asca and the chandra of the central region of the starburst galaxy m82 @xcite . subsequent observations by subaru have revealed that this imbh apparently coincides with a young compact star cluster .
based on these findings , we suggest a new formation scenario for smbhs . in this scenario , imbhs first form in young compact star clusters through runaway merging of massive stars .
while these imbhs are forming , the host star clusters sink toward the galactic nucleus through dynamical friction , and upon evaporation deposit their imbhs near the galactic center .
the imbhs then form binaries and eventually merge via gravitational radiation , forming an smbh . |
molecular hydrogen ( h@xmath9 ) emission lines include some of the brightest lines in the near infrared k - band and are therefore commonly targeted as diagnostic lines .
comparing the ratios in several or more rotational and vibrational transitions allows one to probe the physical conditions of molecular clouds which are illuminated by incident far ultraviolet ( fuv ) radiation or heated by shocks .
a number of authors have also suggested that x - ray irradiation from active galactic nuclei ( agn ) may excite bright h@xmath9 line emission , a conclusion based primarily on the ratio of the h@xmath9 1 - 0s(1 ) line to other emission lines or quantities @xcite .
@xcite thought that this could be important , but that shocks excited by nuclear outflows is a likely mechanism for heating h@xmath9 in many seyfert 2 galaxies .
@xcite rule out x - ray heating as the dominant source of h@xmath9 emission due to the lack of correlation between 1 - 0s(1 ) and hard x - ray flux . instead
, because they spatially resolve the h@xmath9 in a number of seyfert 2 galaxies and one seyfert 1 , they suggest that a variety of different processes are probably involved depending on the object .
the extended nature of the h@xmath9 emission in this seyfert 1 was confirmed by @xcite , who also found extended h@xmath9 emission in other type 1 agn @xcite . in this paper
, we address the issue of h@xmath9 excitation in and around agn from a different perspective : using the ratios of the h@xmath9 lines themselves across several vibrational levels to constrain the dominant excitation mechanism .
this can be a very powerful tool as shown , for example , by our application of h@xmath9 excitation models to ultraluminous infrared galaxies ( ulirgs ) @xcite .
the evidence above that h@xmath9 can be extended in both type 1 and type 2 agn suggests that active star formation , which typically occurs over large ( 0.1 - 1kpc ) scales , could be a good candidate for its origin .
this premise is strengthened by the increasing evidence for active star formation in the tens to hundreds of parsecs around both seyfert 2s @xcite and seyfert 1s @xcite .
we therefore address whether : ( 1 ) the dominant h@xmath9 excitation mechanism either close around an agn or in its wider environment is consistent with excitation in photo - dissocation regions , as one might expect if it originates from star formation ; and ( 2 ) whether suppression of the 2 - 1s(3 ) can be taken as an indicator of x - ray irradiated gas in agn , as has been proposed theoretically and observationally @xcite .
to do so , we have undertaken longslit observations of the 9 seyfert galaxies listed in table [ tab : basdat ] , including both type 1 and type 2 seyferts , although the classification is often an indistinct issue . in order to analyse these ,
we have divided them into two groups : five which are near enough ( @xmath10mpc ) to study both the nuclear and circumnuclear h@xmath9 line ratios separately ; four which are further away ( @xmath11mpc ) , and for which only a nuclear spectrum was extracted . after describing the observations and data reduction in section [ sec : obs ] , we discuss how the stellar continuum was removed and the line fluxes measured in section [ sec : contfit ] .
notes on the individual objects in our sample are given in section [ sec : notes ] before addressing the issues of star formation around the agn and h@xmath9 excitation in sections [ sec : starform ] and [ sec : poplev ] respectively .
finally , our conclusions are presented in section [ sec : conc ] .
our data were obtained as part of the service observing programme at the _ very large telescope _ between may and august 2002 in seeing of typically 0.8 in the k - band .
acquisition images with integration times of a few seconds were taken before each spectrum through a narrow band filter near to 2.1 .
these are shown in fig . [
fig : acq ] together with the orientation of the slit across the nucleus of each object .
the position angle of the slit was set to lie along the major axis of the object as determined from 2mass k - band or red digitised sky survey images . where there was no clear axis ,
the slit was set east - west .
isaac was used in medium resolution mode in the k - band , providing a nominal resolution of @xmath0 with a 1 slit .
since the wavelength coverage in this mode is only 0.122 , two settings were used with an overlap of 510% .
the total integration time was 2000seconds per setting .
standard calibrations were performed , including atmospheric standard stars ( type b or g2v ) , arcs , flatfields , and dark frames .
the data were reduced using pc - iraf 2.11.3 using standard techniques .
wavelength calibration was achieved by tracing the sky lines to create a transformation which removed curvature , at the same time as applying the final wavelength scale .
it was found that the spectral slope in each row of the object spectra had a small residual curvature which depended on the position of the row .
this curvature was removed without affecting the overall slope of each spectrum , allowing a much better merging of the two wavelength segments .
however , this does mean there could be some uncertainty in the slope of the resulting spectra .
the merging was performed on the 2-dimensional spectra , convolving the observation which had better seeing with a moffat function to match the one which had poorer seeing . at the same time
the fluxes of the two spectra were scaled according to their overlapping regions .
the flux calibration was derived from the standard stars , the k - band magnitudes of which were extracted from the 2mass point source catalogue .
there was a very good correspondance between these magnitudes and those estimated from the colour of the spectral type and v - band magnitude , the difference being on average 0.15mag .
slit losses are compensated to zero order by the standard star for each observation .
no further correction was applied since the main theme of the analysis involves line ratios rather than absolute fluxes . since also
the change in atmospheric dispersion in the k - band is small , the data are unaffected by differential slit losses .
the final step in the data reduction was to de - rotate the spectra , as shown in fig .
[ fig : derotate ] , to straighten the rotation curves
. the advantage this brings is twofold .
it restricts the spectral width of all the lines ( emission and absorption ) in a spectrum extracted over a long aperture ; and it decorrelates the noise introduced by systematic residuals from imperfect telluric correction , since these features are no longer aligned with the spatial axis . thus the signal to noise in the spectral features that we wish to measure is significantly increased .
the procedure was performed on the 5 nearby objects , since their rotation curves could be traced out beyond the nucleus . for each of these
, the velocity shift of the 1 - 0s(1 ) line was measured in each spatial row where the line was sufficiently well detected .
these rows were shifted to a zero offset position .
all other spatial rows were shifted according to a function ( the error function , since it provides a simple smooth approximation to a typical rotation curve ) which was fit to the rows where the line offset could be measured .
for all the galaxies listed in table [ tab : basdat ] , we have extracted spectra from the nuclear region , which we define as the central 1 ( to match the typical seeing ) .
this includes everything within 60pc ( for the nearby galaxies ) or 190pc ( for the more distant galaxies ) of the agn .
additionally , for the nearby galaxies we have extracted a circumnuclear spectrum , which we define as everything outside the central 2 ( to reject any nuclear emission ) and up to 1kpc from the agn .
estimations of the contamination of the circumnuclear flux by the nuclear flux in each case and for the ambient seeing indicate that this is less than 10% in the worst case and typically 1% or less . as for our previous work on ultraluminous galaxies
@xcite , we have fit stellar templates ( f m type supergiants from the library of @xcite ) to the continuum in order to be able to measure the line emission accurately . however , because of the broad br@xmath4 in most of the nuclear spectra , it was not practical to mask out regions with line emission .
instead , spectra were fit simultaneously with stellar templates and both broad and narrow emission lines .
the wavelengths of the lines were fixed , and they were assumed to have the same redshift as the stellar continuum . however , the minimisation was allowed to adjust the velocity width of the lines ( one width for all the narrow lines , and one for all the broad lines ) .
while this procedure can match the continuum well , it provides poor estimates of ( particularly the weak ) line fluxes since these are affected by local over-/underestimates in the relative level of the continuum .
the line fluxes were therefore remeasured by fitting gaussian functions of fixed width to the spectrum after the fitted continuum had been subtracted .
the uncertainties were estimated from the standard deviation of the local residual ( covering a spectral range 10 times the fwhm of the line ) and the line widths using monte carlo techniques .
specifically , a spectral segment was constructed to have the same statistical noise properties as the actual residual spectrum , to which a gaussian profile of the measured flux and fwhm was added .
a new gaussian profile was then fitted to the segment , producing slightly different parameters .
this was repeated 10000 times , yielding the uncertainties .
limits were derived in a similar way .
we caution that while this treatment accurately estimates uncertainty from random noise , it can not account for systematic error such as the absolute flux scaling is given in table [ tab : measdat ] , and the line ratios and uncertainties are tabulated in table [ tab : ratios ] .
the circumnuclear spectra of all the targets except ngc5506 had deep absorption features . for these we assumed
there was no contribution from hot dust , but allowed the extinction to vary in order to match the spectral slope . for ngc5506 ,
the very weak nai absorption at 2.206 suggests that the near infrared is not dominated by late - type stars , perhaps because there is a significant hot dust component even away from the nucleus .
the residual broad br@xmath4 also suggests that there may be some contamination from the nucleus . for this spectrum
we not only allowed the extinction to vary , but added a thermal component at @xmath12k representing hot dust .
although there is some degeneracy between these two effects since they both change the spectral slope , the primary aim is to remove the effect of the absorption features rather than uniquely identify the components comprising the continuum ; and in this respect the process is successful . the results of this continuum fitting procedure for the circumnuclear regions are shown in fig .
[ fig : circum - spec - near ] . in all cases except ngc1097 ,
the stellar features in the nuclear spectra are much less clearly defined .
there are two important reasons for this : 1 ) the redder spectral slope indicates that there is a significant contribution from hot dust , which dilutes the stellar continuum and adds to the noise ; 2 ) one would expect a higher velocity dispersion in the nucleus ( particularly if the stellar population is dynamically hot ) which , combined with the steep rotation curve ( albeit corrected ) and seeing lead to a large broadening of the features . in fitting the continuum
we have , in each case except ngc1097 , left both the @xmath12k hot dust contribution and the extinction as free parameters .
the results of the continuum fitting procedure for the nuclear regions are shown in fig .
[ fig : nuclear - spec - near ] for the nearby objects and fig .
[ fig : nuclear - spec - far ] for the more distant objects .
in this section we summarise some notes about the objects in our sample , in order to put into context our data and the results we discuss later . the classification of ngc1097 as a seyfert 1 is based on its broad h@xmath13 line @xcite and hard x - ray excess @xcite , although the agn is low luminosity .
the black hole mass is nevertheless expected to be @xmath14@xmath15m@xmath16 , based on the stellar velocity dispersion and m@xmath17 relation @xcite an order of magnitude more massive than that in the very active ngc7469 @xcite .
monitoring the broad h@xmath13 over a timespan of 11yrs , @xcite indicated that the luminosity decreased to 1/3 of its initial value over this period . during our observations
there was no evidence of broad br@xmath4 and , assuming a velocity width of 7500 fwhm ( similar to that for the total broad h@xmath13 line ) , we can impose a 3@xmath18 limit of @xmath19 ( 1 aperture ) just consistent with the broad h@xmath13 flux measured towards the end of 2001 if extinction is negligible .
however , it is plausible and more likely that the broad component continued dimming towards the middle of 2002 when our data were taken .
the narrow br@xmath4 is also weak in the nucleus , with a flux of @xmath20 in a 1 aperture , indicating that there is little current star formation .
the last episode may have ceased relatively recently , as suggested by the very deep absorption features which even with the use of supergiant templates we have difficulty matching .
ngc1097 therefore offers an excellent opportunity to study the distribution and dynamics of the stars in the region close around a ( quiescent ) agn .
our detection of strong h@xmath9 1 - 0s(1 ) in the nuclear region is in stark contrast to the lack of such emission in the spectrum of @xcite , and we can offer no explanation for this difference . ngc1097 exhibits a very clear and well studied circumnuclear ring @xcite , which is also apparent in our data from the increase in br@xmath4 flux at radii of 89 .
ngc1365 , a strongly barred galaxy in the fornax cluster , has been reviewed extensively by @xcite .
its agn exhibits both broad and narrow components to the h@xmath13 line , the fwhm of the former being 1800 @xcite , somewhat wider than the @xmath12 we find for the br@xmath4 line .
assigning 1800 to the broad component in our data would only be possible if the narrow component had fwhm 500 , in conflict with @xcite reporting it as unresolved .
the soft x - ray ( 0.12.5kev ) luminosity , which can in principle be explained entirely in terms of star formation , suggests the agn is of rather low luminosity @xcite . on the other hand ,
the presence of a relatively unabsorbed power law component at higher ( up to 10kev ) energies and a 6.6kev fe k emission line indicate that there must be an agn @xcite .
the ionisation cone , seen in [ oiii ] and with kinematics indicative of outflowing gas , was modelled by @xcite , who found that the cone axis lay close to the galaxy s rotation axis and the opening angle was sufficient to include the line of sight to the partially obscured seyfert nucleus .
the galaxy has a prominent circumnuclear ring at a distance of 510from the nucleus , which is actively forming stars .
it has been observed in both recombination line and optical / infrared / radio continuum emission and is also clearly seen in our data .
ngc2992 exhibits an extended biconical narrow line region on kpc scales @xcite , which traces outflowing gas .
@xcite were able to model the kinematics in terms of gas rotating in the disk plane and a biconical outflow , and argue that the latter is a thermal wind driven by the agn rather than vigorous star formation . on smaller scales , there is a figure-8 loop of radio continuum and h@xmath13 emission , centered on the nucleus and extending to about 500pc @xcite . using adaptive optics to reach a resolution @xmath21 , @xcite proposed that the loop structure is in fact a superposition of emission from star formation along a spiral arm in the disk and outflow bubbles coincident with the larger scale structures .
in contrast to @xcite , our data show a very significant reduction in the equivalent width of the stellar absorption features ( whether 2.293 co2 - 0 or 2.206 nai ) at the nucleus , which is most easily explained in terms of dilution due to hot dust .
the generally accepted classification of ngc2992 as a seyfert 2 ( or 1.9 ) is perhaps surprising given that it exhibits broad emission lines in the optical and near infrared .
however , given that in the model of @xcite the line of sight is very close to the edge of ( but not within ) the opening angle of the outflow from the agn , a classification close to type 2 makes sense with respect to the standard orientation dependent model . in hard x - rays ( 210kev )
, ngc5506 is one of the most luminous local seyferts @xcite , making it rather unusual amongst type 2s .
however , its x - ray properties are more consistent with those of narrow line seyfert 1s which , based on its j - band spectrum , ngc5506 appears to be @xcite .
our data tend to support this classification .
a detailed study of the kinematics of the double peaked lines by @xcite suggested that the object is a nearly edge - on seyfert .
their model , a refined version of that proposed by @xcite , has the disk plane inclined by 75@xmath22 , above and below which ionised gas is outflowing in cones extend with opening angle @xmath23 .
a highly inclined geometry is consistent with the hard x - ray spectrum , for which the lack of evidence for an accretion disk from the ionised component of the 6.4kev iron line suggests that it must be nearly edge - on @xcite .
@xcite also argue that , based on the observed trends in emission line ratios , there is significant star formation occuring at distances of 300400pc from the nucleus that can account for about half of the h@xmath13 emission .
our data confirm the evidence for active star formation close to the agn , showing symmetrical dips in the 1 - 0s(1)/br@xmath4 ratio at offsets of @xmath2422.5(250300pc ) from the nucleus .
ngc7582 is the brightest narrow line x - ray galaxy , and perhaps prototypical of this class @xcite . that it has an agn
can not be doubted , due to the rapid and large variations in hard ( 210kev ) x - ray flux occuring while the soft ( 0.52kev ) x - ray flux remianed constant @xcite , and the presence of an [ oiii ] ionisation cone @xcite .
@xcite noted the appearance and subsequent variations in a broad component to several optical emission lines .
we also have detected a broad bump in the k - band spectrum , which most likely corresponds to broad ( @xmath25 ) br@xmath4 .
this is also apparent in the nuclear spectrum of @xcite , who noted the complex morphologies of the emission lines .
@xcite reached no consensus on whether this type 2 to type 1 transition was due to the appearance of type iin supernovae or to patchy obscuration in the torus aorund the agn . by examining the fuv flux
, @xcite found evidence for young stars in the nucleus ( central 2 ) of ngc7582 , superimposed on the older bulge population .
we also see relatively strong nai absorption in the spectrum of the central 100pc .
on the other hand , the equivalent width of this absorption feature decreases steadily from a radius of @xmath243 ( 300pc ) to a minimum at the nucleus of @xmath26 .
this feature could imply a transition to a rather young stellar population , or more likely the presence of hot dust grains although whether the heating on such extended scales can be attributed to the agn is unclear .
an _ hst _ image of mrk1044 shows it to be a spiral galaxy inclined by about @xmath27 from face - on @xcite , and it is included in the list of 59 narrow line seyfert 1 galaxies complied by @xcite . as is typical of such objects
, it has a steep soft x - ray photon index and shows some variability @xcite . a spectrum covering 0.82.4micron presented by @xcite shows no emission lines in the h - band and , as also found by @xcite and ourselves , only br@xmath4 in the k - band .
although their spectrum becomes somewhat less sparsely populated shortward of the h - band , presumably because the dilution of features by hot dust continuum is much less , they still do not detect any coronal lines . in this galaxy
we detect neither stellar absorption features , nor h@xmath9 line emission ( compact or extended ) .
this paucity of emission or absorption features makes it extremely difficult to draw any conclusions about excitation mechanisms or dynamics .
ngc1194 is a highly inclined spiral galaxy .
it was classified as a seyfert 1 by @xcite , who were surveying warm iras sources , based on optical line widths and ratios . in a survey of 12 galaxies , @xcite ( who classed it as a type 2 , as given in the original sample definition ) obtained a 2.84.1 spectrum of this object , finding no 3.3 pah emission , but evidence for coronal [ siix ] at 3.9 .
our detection of only narrow br@xmath4 would tend to support the seyfert 2 classification .
@xcite observed strong co bandhead absorption longward of 2.3 and we too , as for more than half of the nuclear spectra in our sample , find relatively strong stellar absorption features present in the nuclear spectrum suggesting that recent or currently active star formation is an important component of its nuclear energy budget .
eso438-g9 was discovered to be a seyfert galaxy by @xcite , who also noted that it has strong optical feii lines , weak or absent higher ionisation lines ( probably due to the steep fuv spectrum ) , and double absorption features blueward of h@xmath13 and h@xmath28 . in their survey of warm infrared galaxies , @xcite noted that this object had strong broad balmer lines , and that particularly the [ oiii ] line had broad wings .
the r - band image of @xcite shows it to be a spiral galaxy with a very bright unresolved nucleus .
we observe a broad pedestal to the br@xmath4 line with a fwhm of 2000 .
there are also clear stellar absorption features in the nuclear spectrum , indicating a significant contribution to the k - band continuum from late type stars within a few hundred parsecs of the agn .
our spectrum of ngc7469 is similar to that of @xcite , showing fairly deep absorption features as well as both narrow and broad br@xmath4 emission .
although this galaxy is considered to be a proto - typical seyfert 1 , much of the attention it has received is focussed on the circumnuclear ring on scales of @xmath292.5 which is responsible for about half of the galaxy s bolometric luminosity . additionally , about one third of the k - band continuum in the nucleus itself originates in star formation @xcite . comparing the luminosity profile of the 1 - 0s(1 ) line with its dynamics at a resolution of @xmath300.1 ( and also the dynamics of the cold molecular gas at 0.7 resolution ) , @xcite concluded that the very central peak in the 1 - 0s(1 ) emission was not associated with the gas or star forming distributions , and was most likely to originate in gas irradiated by x - rays from the agn .
unfortunately , in a 1 aperture , the 1 - 0s(1 ) flux from this component is expected to contribute only about 2025% of the total 1 - 0s(1 ) flux .
it may not be possible on seeing limited scales to resolve the more extended dominant component , that is presumably excited by star formation , from the nuclear point source .
in the previous section we have noted several times that deep stellar absorption features are often present even in the central 100pc around the agn . in this section
we assess the evidence for active star formation in these regions , particularly since this will enable us to place the following discussion of the h@xmath9 excitation mechanisms in context .
high spatial resolution spectroscopy has already provided direct evidence for intense star formation on scales as small as a few tens of parsecs , and even a few parsecs , around several type 1 agn , namely ngc7469 @xcite , mkn231 @xcite , ngc3227 @xcite .
other authors ( e.g. * ? ? ?
* ; * ? ? ?
* ; * ? ? ?
* ) have demonstrated through empirical population synthesis that in about 40% of type 2 seyferts there is recent ( i.e. @xmath301gyr ) star formation within a few hundred parsecs of the nucleus .
it is therefore expedient that we consider whether there could be active and intense star formation in the central apertures of the agn presented here .
[ fig : spat - near ] shows , for each of the five nearer galaxies , the spatial distributions of various quantities along the slit to a projected distance of 1kpc from the centre .
the top panels trace the relative surface brightnesses of the total k - band continuum together with the stellar continuum , 1 - 0s(1 ) and br@xmath4 line emission , the latter two with the same normalisation .
we have attempted to measure only the narrow br@xmath4 . however , in several cases this is difficult to separate from the broad emission ( see fig . [
fig : nuclear - spec - near ] ) and hence over the central arcsec should be taken as a guide only .
the centre panels show the equivalent width of the 2.206 nai stellar absorption line , @xmath31 . to assist in interpreting this ,
we show also the typical range of values ( 23 ) that one would expect it to take .
this is based on results of the stars star formation models @xcite shown in fig .
[ fig : ewna ] .
this code calculates the distribution of stars in the hertzsprung - russell diagram as a function of age for an exponentially decaying star formation rate .
using empirically determined @xmath31 from library spectra @xcite , the code then computes the time - dependent @xmath31 for the entire cluster of stars .
the code includes the thermally pulsing asymptotic giant branch ( tp - agb ) stars which have a very significant impact on the depth of the absorption features at ages of 0.4 - 2gyr @xcite .
the stellar continuum in the top panel is derived assuming it exhibits a constant equivalent width , which this figure shows to be a reasonable zero - order approximation . finally , the bottom panels in fig .
[ fig : spat - near ] show how the colour of the continuum , defined here as the ratio of the flux densities at 2.19 and 2.25 , varies along the slit .
again , several reference values are superimposed : the range of colours typical of late type stars , and the colour of a blackbody continuum at 1500k representative of hot dust associated with an agn .
extinction is unlikely to change these colours significantly since the relevant quantity is the differential extinction between 2.19 and 2.25 .
this only starts to become important for screen extinction models with @xmath32 . in general , away from the nucleus itself ,
@xmath31 is consistent with what one expects from the star formation models , indicating that there is little or no dilution .
the nuclear br@xmath4 emission at these radii ( e.g. ngc1097 , ngc1365 ) is indicative of young stars , and the spatial coincidence of 1 - 0s(1 ) emission would suggest that it is a related phenomenon : either from photo - dissociation regions or associated with supernovae . in this sense , the occasional peaks with @xmath33could be due to the stars in individual clusters passing through the late - type supergiant phase at @xmath3410myr .
however , the regions close around the nucleus tell a rather different story .
the stellar continuum appears to increase steeply ; but in every case @xmath31 exhibits a dramatic decrease , which is also associated with a reddening of the continuum colour .
the simplest explanation is that the stellar continuum is strongly diluted by continuum emission from hot dust .
if these features were unresolved , as in ngc1097 , one would immediately assign them to dust heated to 5001500k by the agn .
but more typically , they occur over an extent of 200pc or more and are therefore unlikely to be directly associated with an agn which is expected to heat grains to such high temperatures over rather limited distances for example the inner edge of a canonical torus on parsec scales or very small grains transiently heated by a jet , as may be occuring in the central few tens of parsecs in ngc1068 @xcite .
agn often exhibit ionisation cones which can extend over distances of hundreds of parsecs , and both ngc1365 and ngc7582 possess one @xcite .
our slits for these two objects are oriented through the ionisation cones .
but over the 5 regions corresponding to the extent of the cones , the respective data sets show totally different properties from each other suggesting that the observations are not tracing processes associated with the ionisation cones themselves .
in addition , the ionisation cone in ngc4945 @xcite , shows that one would not expect them to produce significant k - band continuum : these authors only see the cone in continuum ( j - band rather than k - band ) because it reduces the extinction to the starlight behind . based on this
, one would expect the cone neither to dilute the stellar features nor to redden the continuum .
we conclude that the agn and its associated phenomena such as ionisation cones are unlikely to produce the combination of properties we observe here .
on the other hand , the reduction in @xmath31 and reddening of the continuum colour are spatially coincident with the brighter stellar continuum , and so as for the circumnuclear regions further out could be associated with active star formation .
the approximate coincidence of br@xmath4 emission provides additional circumstantial evidence for a population of very young stars , or at least on - going star formation .
the dilution of the stellar features and reddening of the continuum colour are still most likely attributable to hot dust , although at present one can only make conjectures about the heating source .
it has been suggested that a population of very small grains could be heated to temperatures of 5001000k by young stars ( e.g. * ? ? ? * ; * ? ? ? * ) .
however , there is little evidence for such a process seen in galactic hii regions . on the other hand , the environment of the region around the agn in terms of density , pressure , turbulence , energetics , etc .
may be sufficiently different from that of galactic hii regions that it is able to produce a population of sufficiently small grains , as well as drive them near enough to the young stellar clusters so that they can be heated .
one could also envisage other processes which may be at work , such as compton heating by energetic photons from the agn .
however , addressing the issue of the dust heating mechanism is beyond both the data presented here and the scope of this work .
the pertinent issue is that for these extended ( @xmath34200pc ) nuclear regions , one must consider all the observed characteristics together : the line emission , reduction in @xmath31 , reddening of the continuum , and also the brightness of the stellar continuum .
a natural , and arguably the simplest , explanation to account for all these simultaneously is the presence of active star formation , from which the combination of direct emission ( e.g. bright stellar continuum ) and indirect emission ( e.g. recombination lines and plausibly hot dust re - radiation ) can account for what has been observed .
for the h@xmath9 line fluxes listed in table [ tab : measdat ] and [ tab : ratios ] , we have calculated the implied molecular column densities , @xmath35 , in the upper rotational - vibrational ( @xmath36 ) levels of the observed transitions , where @xmath37 is the observed flux , @xmath38 is the radiative rate , and @xmath39 is our aperture size .
we assume that the quadrupole transitions are optically thin and we use the radiative @xmath38 values as given by @xcite .
after normalising the population distributions to the @xmath40 level ( i.e. the 1 - 0s(1 ) line ) , we have plotted them as @xmath41 ( where @xmath42 is the statistical weight ) against energy ( in k ) of each observed @xmath36 level . in such excitation diagrams , the log@xmath43 points for isothermal populations should lie on a straight line . in order to interpret these diagrams , we consider purely thermal emission as well as a representative set of 5 pdr models which are described by @xcite .
these models consist of static , plane - parallel , semi - infinite clouds that are exposed to isotropic fuv radiation fields @xcite . at each cloud depth
we compute the equilibrium atomic to molecular hydrogen density ratio , @xmath44 , and we solve for the steady - state population densities in the rotational and vibrational h@xmath9 levels in the ground electronic state . in solving for the @xmath36 populations we include the effects of fuv - pumping via the lyman and werner bands , collisional processes with h@xmath45 , h , and h@xmath9 , and quadrupole radiative decays .
the 5 models cover a range of illuminating fuv field intensities @xmath46 , relative to the fuv field in the local interstellar medium ( @xmath47photonss@xmath48m@xmath49 over 9121130 , * ? ? ?
* ) , and total hydrogen particle densities @xmath50 in the clouds . in all of the models except model 1
( for which we keep the temperature constant at @xmath51k ) , we assume that the gas temperature varies with cloud depth and set the temperature at the cloud edge . the gas temperature is a maximum in the outer atomic zone and declines significantly to @xmath52k as the gas becomes molecular , a behaviour that is consistent with both theoretical expectations for , and empirical measurements of , dense pdrs .
the details of the models and a description of their salient features is given by @xcite and are not repeated here .
instead , we summarise the parameters ( @xmath46 , @xmath53 , @xmath54 ) in table [ tab : models ] .
the excitation diagrams for the models are plotted in fig .
[ fig : poplev - model ] , which shows the extent of their coverage of the relative population parameter space . what is immediately clear from the mean values for the nuclear and circumnuclear spectra , shown in fig .
[ fig : poplev - mean ] ( where the error bars denote the standard devation of the values among the objects ) , as well as from the individual values is that the @xmath55 levels are well thermalised . in every case
these levels can be reproduced by an isothermal cloud at 1300k .
however it is not possible to say from just the @xmath55 levels whether the h@xmath9 molecules have been excited by a thermal process such as a shock front , or whether it is due to high gas density regardless of the mechanism which provides the energy .
the higher levels suggest the latter since in every case they lie above the prediction for 1300k . to compensate for this
, one would need either multiple thermal components , or a fluorescent component .
the former is not a satisfactory solution because the temperature needed about 3000k between the @xmath55 and @xmath56 levels , and of order 5000k between the @xmath56 and @xmath57 levels would mean that the molecules are rapidly dissociated .
the possibility that instead a fluorescent excitation mechanism is responsible for the @xmath56 and @xmath57 populations is given by the blue symbols in the figures , which represent our pdr model 2 .
in this model , the @xmath55 levels are collisionally thermalised as a result of the high @xmath58@xmath59 gas density .
in addition , the model exhibits a shift in the ortho - para ratio for the @xmath56 levels : the @xmath60 para level is above the adjacent @xmath61 and @xmath62 ortho levels .
suppression of the ortho - para ratio below the value of 3 obtained in local thermal equilibrium in warm gas is a typical signature of excitation by fuv pumping . it occurs because the ortho uv absorption lines have a higher optical depth , and hence the vibrationally pumped ortho - h@xmath9 is suppressed with respect to para - h@xmath9 @xcite .
it is exactly this effect that can be seen in the h@xmath9 population diagrams of the agn for which all 3 relevant lines have been detected , both in the nuclear and circumnuclear regions . of the 5 pdr models we consider covering the parameter space fuv intensity @xmath63-@xmath64 times that in the local interstellar medium , gas density @xmath65-@xmath66@xmath59 , and temperature @xmath67-@xmath68k it is model 2 and 4 ( differing only in fuv intensity , and indistinguishable in terms of their resulting line ratios ) which best match the data .
this indicates that the maximum temperature is @xmath12k ( as one would expect from the @xmath55 levels discussed above ) , the gas density is of order @xmath69@xmath59 , and the incident fuv intensity is at least @xmath70 times the local ambient value .
model 2 provides a reasonable match to all the data in the mean diagram ( fig .
[ fig : poplev - mean ] ) , and is the model we use as a reference when considering the individual objects , the excitation diagrams for which are shown in figs .
[ fig : poplev - near ] and [ fig : poplev - far ] . in all of the five galaxies belonging to the nearby sample
, the circumnuclear line ratios can be reproduced by model 2 and in the case of ngc2992 the match is remarkably good .
there are a few isolated cases where line limits appear to be inconsistent with the model , but in at least some cases these limits appear to be unphysical : for example , in none of our models is the @xmath71 less than the @xmath72 and @xmath73 levels . in this case
the 2 - 1(2 ) line is significantly weaker than 2 - 1s(1 ) and 2 - 1s(3 ) due to its smaller statistical weight and occurs in the overlap region of the two spectral segments where small uncertainties in scaling the two segments can have a disproportionate effect that is not reflected in the estimation of the line flux uncertainty .
similarly , the @xmath74 level is derived from the 3 - 2s(3 ) line which sits close to the edge of the 2.206 na absorption which can often be quite deep .
a description of how the uncertainties were estimated is given in section [ sec : contfit ] , but any such estimate can not take into account systematic errors such as incorrect removal of the continuum features due to mismatch of the stellar templates . bearing this in mind , one should be cautious of the uncertainties when a weak line or non - detection occurs close to a region of strong stellar absorption , and not over - interpret them when assessing the correspondance between model and data .
the conclusion that in all five cases the h@xmath9 lines appear to be excited in dense pdrs exposed to high fuv fields is consistent with what one might expect of regions efficiently forming massive young stars at a high rate .
the data for the nuclear line fluxes is much less complete , primarily due to the greatly increased noise in the spectrum from the bright hot dust continuum associated with the agn . nevertheless , in three of the four nearby galaxies where h@xmath9 lines are detected
namely ngc1097 , ngc2992 , and ngc5506 their ratios show a strong similarity to those of the circumnuclear regions , with the single exception of the @xmath75 level in ngc1097 which is a factor of @xmath342 less than one would expect .
the fourth galaxy , ngc7582 , is similar for all the levels up to and including @xmath72 , but the @xmath74 level is significantly higher than one would expect : none of our pdr models can reproduce this .
examination of the region around the 3 - 2s(3 ) line at 2.2 in fig .
[ fig : nuclear - spec - far ] suggests that in ngc7582 it also seems likely that template mismatch and hence incomplete correction of the absorption features in the stellar continuum has led to poor estimation of the weak line flux . in none of these galaxies
do we find evidence for suppression of the 2 - 1s(3 ) line , which might be expected for agn if the gas irradiated by x - rays .
this is a theoretical possibility if there is an excess of ly@xmath13 photons , due to an accidental resonance between the 1 - 2p(5 ) and 1 - 2r(6 ) transitions and the ly@xmath13 line @xcite .
an excess of ly@xmath13 photons will depopulate the lower ( i.e. @xmath76 and @xmath77 ) levels , resulting in a reduction in the two 2 - 1s(3 ) and 2 - 1s(4 ) line strengths .
such a situation could arise in x - ray irradiated gas , in which the primary photoelectrons have high enough energies to generate many more secondary ionisations ( @xmath78 per kev of primary photoelectron energy ; @xcite ) through collisional excitation .
it has been proposed by @xcite as the explanation for a previously reported weakness of that line in ngc6240 . however , using higher resolution and signal - to - noise spectra , @xcite showed that this line is in fact not suppressed , and that the @xmath550 and 21 transitions can be well matched by models of isothermal emission .
a second case is ngc1275 , which has very luminous h@xmath9 emission ( @xmath79 ) mostly concentrated in a compact ( @xmath340.5 ) nuclear source @xcite . interpreting the line ratios in terms of thermal excitation with two or more excitation temperatures
, @xcite argued that the flux of the 2 - 1s(3 ) line was a factor of at least 2.5 less than expected and attributed this to the fact that the excitation of the gas is dominated by x - ray heating from the agn .
we plot the data for the central 3 of ngc1275 ( from their table 2 ) in fig .
[ fig : poplev-1275 ] .
it is clear that these data tend towards the same trend we have seen in our seyfert nuclei : the @xmath1 transitions appear thermalised while the higher vibrational transitions indicate an additional higher temperature thermal or fluorescent ( pdr ) component .
the levels from our pdr model 2 ( overplotted as squares ) go some way to explaining the observed ratios and the apparent weakness of the ( 2,5 ) level .
a pdr model with low density fluorescence ( our model 1 ; overplotted as triangles ) , matches the @xmath7 and @xmath3 levels extremely well if it is scaled to produce 1/3 of the total 1 - 0s(1 ) flux .
it does not reproduce the @xmath80 levels at all ; but it is not unreasonable to suppose that in such a large aperture ( 3 is equivalent to 1kpc ) there may be multiple excitation processes at work and that the @xmath81 levels could arise from a region where thermal processes dominate and the higher levels from a region where non - thermal processes dominate . in the nuclear specta of our agn ,
the line ratios are , as for the circumnuclear regions , consistent with excitation by intense star formation in relatively dense pdrs .
this appears to be the case even for ngc5506 which has a very luminous seyfert nucleus . on the other hand ,
determining whether the data are consistent with x - ray excitation is not straightforward .
from their models of x - ray irradiated gas , both @xcite and @xcite conclude that the 2 - 1s(1 ) to 1 - 0s(1 ) ratio should nearly always be @xmath82 ; most of the diagnostic power of these models appear to lie in transitions from @xmath83 or far infrared lines from other species .
instead we consider the 210kev hard x - ray fluxes , which are listed in table [ tab : measdat ] .
these indicate that , as also found by @xcite , there is absolutely no correlation between x - ray and h@xmath9 emission
. this could be either because the two are not causally related , implying a different excitation mechanism for the h@xmath9 ; or due to the different timescales for variability .
the hard x - ray luminosities are known to vary on fast timescales
e.g. by a factor of 2 over a period of a few hours for ngc1365 @xcite and ngc7469 @xcite while the h@xmath9 emission would only vary on the far longer timescales associated with its physical extent ( @xmath84pc implies @xmath34300yrs ) . for ngc1097 nuclear h@xmath9 excitation by star formation rather than an agn can be understood because the agn is in general rather low luminosity ( see section [ sec : notes ] ) . and in ngc1097 , ngc2992 , and ngc7582 fig .
[ fig : nuclear - spec - far ] indicates that the nai stellar absorption is clearly visible despite ( in the latter 2 cases ) strong dilution by the agn . as discussed in section [ sec : starform ] , this suggests that in these cases there may be significant active star formation in the nucleus and as a result any h@xmath9 emission from x - ray excited gas could be hidden by emission from pdrs excited by the young stars .
of the four more distant galaxies , h@xmath9 emission was detected in three
namely ngc1194 , ngc7469 , and eso438-g9 but the data is sparser still than the nearby ones . beyond the statement that the @xmath55 levels are thermalised but the higher levels indicate fluorescent excitation , there is little that we can conclude
this in itself suggests that the @xmath55 levels are thermalised due to high gas density rather than purely thermal excitation in shocks , consistent with the results for the nearby galaxies . that the excitation could be due to active star formation is evidenced by the nai absorption which can be seen in these three nuclei despite the agn dilution
however , we can make no statement on whether the gas is also ( or instead ) being irradiated by x - rays from the agn . in ngc7469 the low populations in the @xmath72 and @xmath73 levels hint that perhaps even the @xmath56 levels are partially thermalised
i.e. that the gas density may be as high as @xmath85@xmath59 as in model 5 , which better reproduces these lower populations
. given the extremely large cold molecular gas mass in the nuclear region of this galaxy , inferred from co2 - 1 observations @xcite , very high gas densities in the clouds themselves are to be expected .
we have presented k - band spectra of the central regions of nine agn , for five of which we also present circumnuclear spectra . in these spectra , we have measured h@xmath9 emission line fluxes from the @xmath86 , 2 , and 3 levels .
we performed two critical steps which enabled us to significantly increase our sensitivity to the weak lines : the first is to fit the continuum with stellar templates , allowing us to remove the absorption features ; the second is to de - rotate the spectra , decorrelating noise from imperfect telluric correction while simultaneously correlating signal from the emission lines .
broad br@xmath4 ( i.e. fwhm @xmath87 ) is observed in seven of the nine nuclear spectra .
we conclude the following : 1 .
use of the ratios of the @xmath55 - 0 transitions , either between themselves or with other lines such as br@xmath4 , h@xmath13 , or [ oi]@xmath88 can be misleading since in starburst and agn environments , these levels are often ( and perhaps almost always ) thermalised without necessarily implying shock excitation .
indeed , we have shown strong evidence that fluorescent excitation plays a major role in the h@xmath9 excitation .
the h@xmath9 line ratios in the circumnuclear regions are very similar in all cases .
while the @xmath55 levels are thermalised at @xmath341000k , fuv - pumped gas is needed to account for the higher levels , consistent with emission from high density pdrs . in our pdr models , the typical parameters that best account for the observed line fluxes are gas density @xmath89@xmath59 , temperature at the outer edge of the clouds @xmath6k , and illuminating fuv fields @xmath90 times more intense than the local interstellar field .
these parameters are similar to those found for the nuclei of ulirgs by @xcite .
the h@xmath9 line ratios in the nuclear regions are also similar in that the @xmath55 levels are thermalised at @xmath341000k but the higher levels require fuv pumping .
the observed line ratios can be accounted for by h@xmath9 excitation occupying a similar parameter space to that found for the pdrs in the circumnuclear regions , suggesting that the mechanism dominating the nuclear h@xmath9 emission could be illumination of pdrs by intense young star formation .
we find no evidence for suppression of the 2 - 1s(3 ) line , which may occur in x - ray irradiated gas .
we suggest that even in the case of ngc1275 @xcite , the h@xmath9 line ratios can be explained without recourse to such a phenomenon .
this does not mean that such suppression does not occur simply that on scales of @xmath84pc , x - ray heating is probably not the dominant excitation mechanism .
5 . despite strong dilution by a red continuum , probably associated with hot dust grains , stellar nai absorption at 2.206
is seen in six of the nine nuclear spectra , suggesting that even on scales as small as 100pc star formation is an important and active process in agn .
the authors are grateful to the staff at the paranal observatory for carrying out in service mode the observations presented in this paper ; and to the referee for a number of comments and suggestions . as thanks the israel science foundation ( grant 221/03 ) for support .
ngc1097 & sy1 & 02 46 19.0 & @xmath9130 16 30 & 1275 & 18 & 90 & 0.7 , 1.0 + ngc1365 & sy1.8 & 03 33 36.4 & @xmath9136 08 25 & 1640 & 23 & 110 & 0.8 , 0.8 + ngc2992 & sy2 & 09 45 42.0 & @xmath9114 19 35 & 2310 & 33 & 160 & 0.7 , 0.7 + ngc5506 & sy1.9 & 14 13 14.8 & @xmath9103 12 27 & 1850 & 27 & 130 & 1.4 , 0.6 + ngc7582 & sy2 & 23 18 23.5 & @xmath9142 22 14 & 1580 & 23 & 110 & 1.2 , 0.8 + mrk1044 & sy1 & 02 30 05.4 & @xmath9108 59 53 & 4930 & 71 & 330 & 0.8 , 0.7 + ngc1194 & sy1 & 03 03 49.1 & @xmath9101 06 31 & 4060 & 58 & 270 & 1.3 , 0.7 + eso438-g9 & sy1.5 & 11 10 48.0 & @xmath9128 30 04 & 7010 & 101 & 470 & 0.5 , 0.8 + ngc7469 & sy1.2 & 23 03 15.6 & @xmath9208 52 26 & 4890 & 70 & 330 & 0.6 , 0.5 + ngc1097 & 1.99 & 5.51 & 44.5 & 85.3 & 2 & 11.8 & 3.10@xmath240.04 & 4.5 & 10.64 + ngc1365 & 3.37 & 10.8 & 76.1 & 142.5 & 5 & 9.8 & @xmath300.78 & @xmath304.1 & 11.09 + ngc2992 & 0.49 & 1.26 & 8.50 & 24.9 & 5 & 10.1 & 8.63@xmath240.06 & 5.4 & 10.54 + ngc5506 & 1.28 & 3.64 & 8.41 & 8.89 & 90 & 9.3 & 6.08@xmath240.18 & 5.1 & 10.41 + ngc7582 & 1.62 & 6.44 & 49.1 & 72.9 & 17 & 11.4 & 1.52@xmath240.06 & 4.4 & 10.85 + mrk1044 & 0.10 & 0.22 & 0.43 & 0.88 & & 11.3 & @xmath300.19 & @xmath304.4 & 10.08 + ngc1194 & 0.27 & 0.51 & 0.77 & 0.93 & & 12.5 & 0.24@xmath240.03 & 4.4 & 10.21 + eso438-g9 & 0.32 & 0.62 & 3.14 & 4.22 & & 11.0 & 1.90@xmath240.05 & 5.8 & 11.03 + ngc7469 & 1.35 & 5.79 & 25.9 & 34.9 & 30 & 10.4 & 6.47@xmath240.12 & 6.0 & 11.59 + + ngc1097 & 0.367@xmath240.022 & @xmath300.119 & 0.220@xmath240.013 & 1.000@xmath240.014 & 0.130@xmath240.016 & @xmath300.053 & 0.330@xmath240.018 & 0.199@xmath240.013 + ngc1365 & 0.379@xmath240.011 & 0.063@xmath240.015 & 0.230@xmath240.008 & 1.000@xmath240.007 & 0.111@xmath240.010 & 0.043@xmath240.010 & 0.340@xmath240.011 & 0.189@xmath240.007 + ngc2992 & 0.404@xmath240.017 & @xmath300.040 & 0.164@xmath240.010 & 1.000@xmath240.009 & 0.075@xmath240.013 & 0.090@xmath240.010 & 0.310@xmath240.009 & 0.178@xmath240.010 + ngc5506 & 0.308@xmath240.018 & @xmath300.046 & 0.178@xmath240.012 & 1.000@xmath240.013 & @xmath300.045 & @xmath300.027 & 0.257@xmath240.008 & 0.142@xmath240.011 + ngc7582 & 0.368@xmath240.010 & @xmath300.041 & 0.168@xmath240.009 & 1.000@xmath240.006 & @xmath300.027 & 0.053@xmath240.011 & 0.270@xmath240.012 & 0.146@xmath240.008 + mean & 0.365@xmath240.032 & @xmath300.061 & 0.192@xmath240.028 & 1.000@xmath240.010 & 0.105@xmath240.023 & 0.062@xmath240.020 & 0.301@xmath240.033 & 0.171@xmath240.023 + + ngc1097 & 0.378@xmath240.015 & @xmath300.046 & 0.163@xmath240.009 & 1.000@xmath240.012 & 0.107@xmath240.013 & 0.069@xmath240.007 & 0.254@xmath240.009 & 0.091@xmath240.009 + ngc1365 & + ngc2992 & 0.310@xmath240.019 & @xmath300.071 & 0.180@xmath240.014 & 1.000@xmath240.007 & 0.126@xmath240.026 & 0.128@xmath240.022 & 0.346@xmath240.019 & 0.147@xmath240.018 + ngc5506 & & @xmath300.168 & 0.173@xmath240.039 & 1.000@xmath240.030 & @xmath300.225 & @xmath300.065 & 0.333@xmath240.030 & @xmath300.138 + ngc7582 & 0.490@xmath240.036 & @xmath300.228 & 0.277@xmath240.045 & 1.000@xmath240.039 & @xmath300.283 & 0.233@xmath240.041 & 0.406@xmath240.045 & 0.175@xmath240.045 + + mrk1044 & + ngc1194 & & @xmath300.333 & 0.509@xmath240.093 & 1.000@xmath240.120 & @xmath300.199 & @xmath300.242 & @xmath300.232 & @xmath300.258 + eso438-g9 & 0.339@xmath240.022 & @xmath300.122 & 0.147@xmath240.029 & 1.000@xmath240.027 & 0.133@xmath240.019 & 0.172@xmath240.022 & 0.332@xmath240.029 & + ngc7469 & &
@xmath300.062 & 0.069@xmath240.019 & 1.000@xmath240.019 & 0.104@xmath240.014 & @xmath300.042 & 0.290@xmath240.013 & 0.086@xmath240.017 + mean & 0.379@xmath240.068 & @xmath300.147 & 0.217@xmath240.132 & 1.000@xmath240.036 & 0.118@xmath240.012 & 0.150@xmath240.054 & 0.327@xmath240.047 & 0.125@xmath240.038 + thermal : 1000k & 0.27 & 0.00 & 0.00 & 1.00 & 0.00 & 0.00 & 0.27 & 0.01 + 2000k & 0.37 & 0.00 & 0.08 & 1.00 & 0.03 & 0.01 & 0.21 & 0.08 + pdr : model 1 & 0.49 & 0.02 & 0.22 & 1.00 & 0.25 & 0.10 & 0.54 & 0.53 + model 2 & 0.32 & 0.04 & 0.15 & 1.00 & 0.08 & 0.07 & 0.33 & 0.17 + model 3 & 0.35 & 0.00 & 0.05 & 1.00 & 0.02 & 0.00 & 0.22 & 0.05 + model 4 & 0.31 & 0.05 & 0.16 & 1.00 & 0.08 & 0.07 & 0.32 & 0.17 + model 5 & 0.29 & 0.02 & 0.10 & 1.00 & 0.04 & 0.04 & 0.33 & 0.11 + 1 & @xmath93 & @xmath70 & @xmath93 & @xmath94 & @xmath95 + 2 & @xmath70 & @xmath58 & @xmath70 & @xmath96 & @xmath97 + 3 & @xmath70 & @xmath58 & @xmath68 & @xmath98 & @xmath99 + 4 & @xmath64 & @xmath58 & @xmath70 & @xmath100 & @xmath101 + 5 & @xmath64 & @xmath66 & @xmath70 & @xmath102 & @xmath103 + | we report @xmath0 very large telescope isaac k - band spectroscopy of the nuclei ( i.e. central 100300pc ) of nine galaxies hosting an active galactic nucleus . for five of these
we also present spectra of the circumnuclear region out to 1kpc .
we have measured a number of molecular hydrogen lines in the @xmath1 , @xmath2 , and @xmath3 vibrational transitions , as well as the br@xmath4 and hei recombination lines , and the nai stellar absorption feature .
although only three of the galaxies are classified as type 1 seyferts in the literature , broad br@xmath4 ( fwhm @xmath51000 ) is seen in seven of the objects .
the @xmath1 emission appears thermalised at temperatures @xmath6k .
however , the @xmath7 and @xmath8 emission show evidence of being radiatively excited by far - ultraviolet photons .
the photo - dissociation region models that fit the data best are , as for the ultraluminous infrared galaxies in @xcite , those for which the h@xmath9 emission arises in dense clouds illuminated by intense fuv radiation .
the nai stellar absorption line is clearly seen in six of the nuclear spectra of these agn , indicating the presence of a significant population of late type stars .
it is possible that these stars are a result of the same episode of star formation that gave rise to the stars heating the pdrs .
it seems unlikely that the agn is the dominant source of excitation for the near infrared h@xmath9 emission : in two of the nuclear spectra h@xmath9 was not detected at all , and in general we find no evidence of suppression of the 2 - 1s(3 ) line , which may occur in x - ray irradiated gas .
our data do not reveal any significant difference between the nuclear and circumnuclear line ratios , suggesting that the physical conditions of the dominant excitation mechanism are similar both near the agn and in the larger scale environment around it , and that star formation is an important process even in the central 100pc acround agn . |
0 during the last few years the interest into theoretical investigations of the quark - gluon structure of light mesons , especially the pion , @xmath9 and @xmath1 mesons , has risen due to the high - precision cleo results on the electromagnetic @xmath10 transition form factors ( ff s ) @xmath11 @xcite ( with @xmath12 denoting one of these mesons ) , as well as because of the observed very large branching ratios for the exclusive @xmath13 and semi - inclusive @xmath14 decays @xcite . the data on the @xmath15 transition ff were mainly used for extracting information concerning the @xmath1 quark component of the meson distribution amplitude ( da ) .
schemes and methods applied to this purpose range from light - cone perturbation - theory calculations with the quark transverse - momentum @xmath16 dependence kept in the hard - scattering amplitude @xmath17 of the underlying hard subprocess @xcite to the modified hard - scattering approach ( mhsa ) with resummed transverse - momentum effects ( giving rise to sudakov suppression factors ) and such due to the intrinsic transverse momentum of the meson wave functions @xcite , to the running coupling ( rc ) method , employed for the estimation of power - suppressed corrections to the @xmath15 transition ff @xcite . in these investigations , two different parameterizations were used , one employing the conventional @xmath18 mixing scheme with one mixing angle @xmath19 @xcite for both physical states and decay constants and a second one , which considers two mixing angles @xmath20 and @xmath21 to parameterize the weak decay constants @xmath22 @xmath23 of the @xmath9 and @xmath1 mesons @xcite . an important conclusion drawn from these investigations , irrespective of the underlying method ,
is that the @xmath1-meson da must be close to its asymptotic form and that the admixture of the first non - asymptotic term should be within the range @xmath24 , @xmath25 being the first gegenbauer coefficient .
the cleo data on the @xmath15 transition and the two - angles mixing scheme were also used to estimate the allowed range of the intrinsic charm content of the @xmath1 meson decay constant @xmath26 @xcite .
it turned out that the value @xmath27@xmath28 does not contradict the cleo data .
but apart from the ordinary light quark and charm @xmath29 components , the @xmath1 meson may also contain a two - gluon valence fock state @xmath30 .
moreover , absent at the normalization point @xmath31 , a gluon component of the @xmath1 meson will appear in the region @xmath32 owing to quark - gluon mixing and renormalization - group evolution of the @xmath1 meson da @xcite .
this can directly contribute to the @xmath15 transition at the next - to - leading order due to quark box diagrams and also affect the leading - order result through evolution of the quark component of the @xmath1-meson da .
hence , an effect of the @xmath1-meson gluon component on the @xmath15 transition is only mild and was therefore neglected in most theoretical investigations @xcite .
but the contribution of the gluon content of the @xmath1 meson to the two - body non - leptonic exclusive and semi - inclusive decay ratios of the @xmath33 meson may be sizeable .
indeed , such a mechanism to account for the observed large branching ratio @xcite @xmath34 was proposed in ref . @xcite . in this work
it was suggested that the dominant fraction of the @xmath35 decay rate appears as the result of the transition @xmath36 of a virtual gluon @xmath37 from the standard model penguin diagram @xmath38 . for the computation of the contribution of this mechanism to the @xmath39 in ref .
@xcite , the @xmath40 vertex function was approximated by the constant @xmath41 , the latter being extracted from the analysis of the @xmath42 decay .
further investigations , however , demonstrated that effects of the qcd running coupling @xmath43 @xcite , as well as a momentum dependence of the form factor @xmath44 , properly taken into account , considerably reduce the contribution to eq .
( [ eq:1.1 ] ) of the mechanism under consideration @xcite . in order to cover the gap between theoretical predictions and experimental data in ref .
@xcite , a gluon fusion ( spectator ) mechanism was proposed . in accordance with the latter ,
the @xmath1 meson is produced by the fusion of a gluon from the qcd penguin diagram @xmath38 with another one emitted by the light quark inside the @xmath33 meson . in this mechanism
, the form factor @xmath45 appears owing to the @xmath46 transition .
the same ideas form a basis for the computation of the branching ratios of various two - body non - leptonic exclusive decay modes of the @xmath33 meson @xcite . to account for the data on the exclusive decay @xmath13 in ref .
@xcite , a mechanism was proposed , based on the assumption of a strong intrinsic charm component of the @xmath1 meson . but a more detailed analysis @xcite proved that the charm content of the @xmath1 is too small ( @xmath47 ) to explain the observed branching ratio @xmath48 .
the cleo data on the @xmath33 meson non - leptonic decays that stimulated interesting theoretical works @xcite remain actual until today @xcite .
the exclusive processes @xmath49 were also analyzed within the qcd factorization approach @xcite and various contributions to the corresponding branching ratios were estimated @xcite . in accordance with ref .
@xcite , the spectator mechanism and such connected to the gluon content of the @xmath9 and @xmath1 mesons are not a key factor in explaining the pattern of the observed experimental data .
instead , a more important role plays here the interference ( constructive or destructive ) of penguin amplitudes and large radiative corrections to them , which bring the predicted branching ratios into reasonable agreement with the data .
the @xmath1-meson virtual-(on - shell-)gluon transition form factor @xmath50 is the central ingredient of analyses performed within perturbative qcd ( pqcd ) and hence requires further thorough investigations .
such theoretical investigations are especially important in view of contradictory predictions made for this ff in the literature @xcite . for instance , in ref . @xcite the contribution of the gluon content of the @xmath1 meson to the form factor @xmath51 was estimated and found to be too small while @xmath51 itself is close to the form @xmath52 used in some phenomenological applications @xcite . on the other hand , in computations of the @xmath1-meson virtual - gluon vertex function @xmath50 , the gluon content of the @xmath1 meson was neglected and the asymptotic form of the da for the quark component was employed @xcite .
the same vertex function @xmath50 was considered in @xcite , where both the standard hsa @xcite as well as the mhsa were used , and the space- , and time - like vertex functions were analyzed .
some errors made in ref .
@xcite in the description of the hard - scattering amplitude of the subprocess @xmath53 and in the definition of the evolution of the @xmath1 meson da were corrected in @xcite .
unfortunately , also this latter work contains an incorrect expression for the gluon component @xmath54 of the form factor , since it is antisymmetric under the exchange of the asymmetry parameter @xmath55 in clear conflict with bose symmetry .
more recently , in ref .
@xcite , the space - like form factor @xmath56 was computed within the standard hsa .
these authors performed a detailed analysis of the normalization of the gluon component of both the @xmath1-meson da and that of the gluon projector onto a pseudoscalar meson state .
in the present work , we investigate the massless @xmath1-meson virtual - gluon space - like transition form factor @xmath56 using the framework of the standard hsa @xcite , as well as by applying the rc method together with the infrared ( ir ) renormalon calculus @xcite .
our results obtained within the standard hsa are in agreement with those of ref .
but our central task here is the calculation and evolution of power - suppressed corrections @xmath57 to the transition ff @xmath58 . because in the production of the @xmath1 meson from the @xmath33 decay the momentum squared of the virtual gluon can vary from @xmath59 to @xmath60 , the power corrections in this domain of @xmath61 are expected to play an important role .
note , however , that we elaborate only on a theoretical framework to compute power corrections for the space - like transition ff .
nevertheless , our technique can be generalized to encompass the time - like transition form factor , relevant for b meson decays , as well .
work in this direction will be reported elsewhere .
the rc method enables us to estimate power corrections coming from the end - point @xmath62 regions ( for definiteness we consider two mesons in an exclusive process ) in the integrals determining the amplitude for an exclusive process .
it is known @xcite that in order to calculate an amplitude of some hadron exclusive process , one has to perform integrations over longitudinal momentum fractions @xmath63 of the involved partons .
if one chooses the renormalization scale @xmath64 in the hard - scattering amplitude @xmath65 of the corresponding partonic subprocess in such a way as to minimize higher - order corrections and allows the qcd coupling constant @xmath66 to run , then one encounters divergences arising from the end - point @xmath62 regions .
the reason is that the scale @xmath64 , as a rule , is equal to the momentum squared of the hard virtual partons , the latter carrying the strong interactions in the subprocess feynman diagrams @xcite and , in general , depends on @xmath67 and @xmath68 . within the rc method
this problem is resolved by applying the ir renormalon calculus .
it turns out that this treatment allows us to evaluate power - behaved corrections to the physical quantity under investigation .
this method was recently used for the computation of power corrections to the electromagnetic form factors @xmath69 of the pion and the kaon , @xcite , and the electromagnetic transition ff s @xmath11 @xcite of the light pseudoscalar mesons .
power corrections to hadronic processes can also be calculated utilizing the landau - pole free expression for the qcd coupling constant @xcite .
this analytic approach was used to compute in a unifying way power corrections to the electromagnetic pion form factor and to the inclusive cross section of the drell - yan process @xcite .
the paper is organized as follows . in sect .
ii we briefly review @xmath70 mixing schemes in the flavor @xmath71 octet - singlet and the quark - flavor bases , and discuss the evolution of the quark and gluon components of the @xmath1 meson da with the factorization scale
. the important question of the generalization of the hard - scattering amplitudes of the @xmath72 transition to the rc method case is also considered .
section iii is devoted to a rather detailed presentation of the rc method . in sect .
iv we compute the quark and gluon components of the transition ff @xmath56 .
section v contains our numerical results .
finally , in sect . vi we make our concluding remarks .
appendix contains an additional information on the @xmath1- meson da .
0 in this section we consider the quark - gluon content of the @xmath1 meson , as well as the @xmath1 da and give some general expressions for determining the @xmath72 transition form factor within both the standard hsa and the rc method . the parton fock state decomposition of the pseudoscalar @xmath75 mesons ,
can be generically written in the following form @xmath76 where @xmath77 and @xmath78 denote the @xmath79-meson light - quarks @xmath80 and @xmath81 , @xmath82 its charm and gluon components , respectively .
fock states with additional gluons and @xmath83 quark - antiquark pairs have been omitted for simplicity .
the @xmath79-meson light - quark content @xmath84 can be described either in the flavor @xmath85 octet - singlet or in the quark - flavor basis . in the first scheme , the states @xmath84 are expressed as superpositions of the @xmath85 singlet @xmath86 and octet @xmath87 states @xmath88 @xmath89 whereas in the quark - flavor basis , the @xmath85 strange @xmath90 and non - strange @xmath91 states are used , i.e. , @xmath92 in eqs .
( [ eq:2.2 ] ) and ( [ eq:2.3 ] ) @xmath93 denote wave functions of the corresponding parton states .
as mentioned above , the charm component of the @xmath1 meson was estimated @xcite to be too small to considerably affect the @xmath33 meson exclusive decays .
therefore , in the present investigation we neglect the charm content of the @xmath1 meson .
the maximal admixture of the two - gluon state in the @xmath1 meson was estimated to be around @xmath94 of its content @xcite .
new results from the kloe collaboration @xcite are compatible with the two - gluon contribution in the @xmath1 meson being below the level of @xmath95 . the pure light - quark sector of the @xmath96 system without charm and gluon admixtures can be treated by means of the basic states ( [ eq:2.2 ] ) or ( [ eq:2.3 ] ) . in the @xmath85 octet - singlet basis ,
the @xmath9 and @xmath1 mesons are expressed as superpositions of the @xmath97 states @xmath98 @xmath99 here , @xmath100 is the mixing angle of physical states in the octet - singlet scheme . in the quark - flavor basis
we get the same expressions but with @xmath19 replaced by the mixing angle @xmath101 of the physical states in the new basis @xmath102 , viz . , @xmath103 @xmath104 the @xmath105 and @xmath106 states and the mixing angle @xmath100 in the octet - singlet scheme can be expressed in terms of the @xmath107 states and the mixing angle @xmath108 in the quark - flavor basis and vice versa . at the level of physical - state mixing
there is no difference between the two bases ( [ eq:2.2 ] ) and ( [ eq:2.3 ] ) .
this only appears when one parameterizes the decay constants @xmath22 of the @xmath109 and @xmath110 mesons in terms of @xmath111 where @xmath112 is the axial - vector currents with @xmath113 or @xmath114 . in the quark - flavor basis
the decay constants @xmath115 follow with great accuracy the pattern of the state mixing @xcite @xmath116 @xmath117 the situation with the parameterization of the decay constants in the octet - singlet basis is different . in this case , in order to take into account the flavor @xmath71 symmetry breaking effects , a two mixing - angles scheme for the decay constants @xmath118 was introduced @xcite @xmath119 @xmath120 the mixing angles @xmath121 and @xmath122 differ from each other and also from the state mixing angle @xmath100 .
nevertheless , in some phenomenological applications the conventional octet - singlet mixing scheme , that is the scheme with one mixing angle and which assumes the equality @xmath123 , is used . in the investigation of physical processes both the octet - singlet and the quark - flavor bases may be used .
a detailed analysis of the @xmath96 mixing problems and further references can be found in ref .
@xcite . in our present work
we choose the quark - flavor basis ( [ eq:2.3 ] ) and the mixing scheme ( [ eq:2.6 ] ) . in this scheme ,
the decay constants @xmath124 and @xmath125 , and the mixing angle @xmath101 have the following values @xcite @xmath126 with @xmath127 being the pion weak decay constant . the kloe result for @xmath128 @xcite
is slightly shifted towards larger values , but it still does not contradict the average value @xmath129 . in our numerical computations
we shall use the central values of the constants shown above .
the singlet part of the @xmath1 meson da meson da is irrelevant for our present investigation and will not be considered here . in what follows we refer to the singlet part of the @xmath1 meson da as being the @xmath1 meson da . ]
@xmath130 was obtained in refs .
@xcite by solving the evolution equation and found to depend on both functions @xmath131 and @xmath132 .
these functions denote the quark and gluon components of the @xmath1 meson da , respectively , and satisfy the symmetry and antisymmetry conditions , @xmath133 this follows from the symmetry properties of the da of the two - particle bound state of a neutral pseudoscalar meson and is in fact enough to obtain general expressions for the @xmath1-meson virtual - gluon transition form factor . the evolution of the functions @xmath131 and @xmath132 with the scale @xmath134 , as well as their dependence on the constants @xmath135 and @xmath101 will be considered in subsect .
ii.c .
the massless @xmath1 meson - virtual gluon transition form factor @xmath137 @xmath138 can be defined in terms of the invariant amplitude @xmath139 for the process @xmath140 in the following way @xmath141 in eq .
( [ eq:2.14 ] ) @xmath142 and @xmath143 are , respectively , the polarization vectors and four - momenta of the two gluons . because we study only the space - like ff , @xmath144 and @xmath145 obey the constraints @xmath146 and @xmath147 .
the form factor @xmath148 depends on the total gluon virtuality @xmath61 and the asymmetry parameter @xmath149 , defined by @xmath150 the asymmetry parameter @xmath151 varies in the region @xmath152 .
the value @xmath153 corresponds to the @xmath110-meson on - shell - gluon transition and the value @xmath154 to the situation when the gluons have equal virtualities @xmath155 . in accordance with the factorization theorems of pqcd at high momentum transfer , the ff s @xmath156
are given by the expressions @xmath157
\otimes \phi ^q(x,\mu _ f^2)\ ] ] and @xmath158 \otimes \phi ^g(x,\mu _ f^2).\ ] ] here , @xmath159 and @xmath160 represents the factorization scale . in eqs .
( [ eq:2.16 ] ) and ( [ eq:2.17 ] ) we have used the notation @xmath161 the sum @xmath162 and the difference @xmath163 represent the hard - scattering amplitudes of the subprocesses @xmath164 and @xmath165 , respectively .
the feynman diagrams contributing at the leading order to these subprocesses amplitudes are depicted in figs .
[ fig : quark ] and [ fig : gluon ] .
= 10 cm = 7 cm = 10 cm = 7 cm in what follows , we omit the subscript @xmath166 in eqs .
( [ eq:2.19 ] ) and ( [ eq:2.20 ] ) and introduce instead the notations @xmath167 @xmath168 in leading order of pqcd , we get for the hard - scattering amplitudes @xmath169 and @xmath170 of the massless @xmath1 meson - virtual gluon transition ff the following expressions @xmath171 @xmath172 and @xmath173},\ ] ] @xmath174}.\ ] ] in deriving the hard - scattering amplitudes @xmath175 ( they are the object of contradictory conclusions in the literature @xcite ) , the following projection operator of the @xmath1-meson onto the two - gluon state has been used @xmath176 note that in the limit @xmath177 the difference @xmath178 , being the physical hard - scattering amplitude , is singularity - free ( see eq . ( [ eq:4.27 ] ) below ) . in the expressions above
, @xmath179 is the qcd coupling constant in the two - loop approximation defined by @xmath180 , \ ] ] with @xmath181 and @xmath182 being the one- and two - loop coefficients of the qcd beta function : @xmath183 in eqs .
( [ eq:2.22 ] ) , ( [ eq:2.23 ] ) , and ( [ eq:2.24 ] ) @xmath184 is the qcd scale parameter and @xmath185 is the number of active quark flavors .
the physical quantity @xmath148 , represented at sufficiently high @xmath61 by the factorization formulas ( [ eq:2.16 ] ) , ( [ eq:2.17 ] ) , is independent of the renormalization scheme and the renormalization and factorization scales @xmath186 and @xmath160 .
truncation of the perturbation series of @xmath187 at any finite order causes a residual dependence on the scheme as well as on these scales . at the leading order of pqcd , the hard - scattering amplitude does not depend on the factorization scale @xmath160 but depends implicitly on the renormalization scale @xmath64 through @xmath66 .. ] an explicit dependence of the function @xmath65 on @xmath188 and @xmath189 appears at @xmath190 due to qcd corrections . as the scales @xmath64 and @xmath189 are independent of each other and can be chosen separately , we adopt in this work the natural and widely used `` default '' choice for the factorization scale @xmath191 and omit in what follows a dependence of the hard - scattering amplitude on @xmath189 ( see , eqs .
( [ eq:2.21 ] ) and ( [ eq:2.22 ] ) ) . for a more detailed discussion of these questions ,
we refer the interested reader to @xcite . in the standard hsa with a `` frozen '' coupling constant @xcite
one sets the renormalization scale to be @xmath192 , simplifying the calculation of the vertex function @xmath56 considerably . in this approach the hard - scattering amplitudes @xmath193 and hence the quark and gluon components of the vertex function @xmath194 possess symmetry features pertaining to the rc method .
indeed , it is not difficult to see that @xmath195 and @xmath196 using eqs .
( [ eq:2.10 ] ) and ( [ eq:2.25 ] ) , we then find @xmath197 @xmath198 in similar manner , using eqs .
( [ eq:2.10 ] ) and ( [ eq:2.26 ] ) , one can demonstrate that the following equalities hold @xmath199 @xmath200 from eqs .
( [ eq:2.27 ] ) and ( [ eq:2.28 ] ) it follows that @xmath201 in pqcd calculations higher - order corrections to various physical processes , are , in general , large and in order to improve the convergence of the corresponding perturbative series , different methods have been proposed . in exclusive processes
- considering the pion electromagnetic form factor as being a prominent example - the next - to - leading order @xmath190 correction contains logarithmic terms @xmath202 ( or @xmath203 ) @xcite , which can be entirely or partly eliminated by a proper choice of the renormalization scale @xmath204 .
this can be achieved by taking as a renormalization scale @xmath205 $ ] or @xmath206 $ ] .
the renormalization scale enters into the pqcd expression not only via logarithmic terms , but also through the argument of the running coupling @xmath207 . in order to calculate the amplitude of an exclusive process , an integration in corresponding integrals over the longitudinal momentum fractions of the quarks and gluons in the involved hadrons has to be carried out .
thus , in the pion electromagnetic ff calculations , the integration over the variables @xmath67 and @xmath68 has to be performed .
traditionally , to avoid problems associated with singularities of @xmath207 , one `` freezes '' the running coupling by replacing @xmath67 and @xmath68 , e.g. , by their mean values @xmath208 in the argument of @xmath207 and performs then the calculation with @xmath209 @xcite .
recently , the rc method for the calculation of various exclusive processes with @xmath207 was proposed . within this framework
, one expresses the running coupling @xmath210 in terms of @xmath211 by employing the renormalization - group equation and performs the integration over @xmath212 using the principal value prescription .
this allows one to estimate power - suppressed corrections to the process under consideration towards the endpoint region of phase space , thus improving the agreement of qcd theoretical predictions with experimental data .
an alternative option to calculate power - behaved contributions with their coefficients would be to use the analytic perturbation theory @xcite along the lines proposed in @xcite .
next - to - leading order corrections are known for only a few exclusive processes @xcite . in general , the renormalization scale @xmath188 may be taken equal or proportional to the square of the four - momentum @xmath213 of the virtual parton(s ) mediating the strong interaction in corresponding leading - order feynman diagrams . for the @xmath110-meson on - shell gluon transition ( i.e. , for @xmath153 ) ,
we adopt in this paper the choice @xmath214 the renormalization scales ( [ eq:2.32 ] ) are equal to the momentum squared @xmath215 of the virtual partons ( gluon or quark ) in the corresponding feynman diagrams . in the general case ( @xmath216 ) , the absolute value of the square of the four - momenta @xmath213 of the virtual partons depends on both the total gluon virtuality @xmath61 and the asymmetry parameter @xmath149 . however , for the sake of simplifying the calculations and to avoid problems related to the appearance of two parameters @xmath61 and @xmath149 in the argument of @xmath217 , we shall use a renormalization scale of the form given in eq .
( [ eq:2.32 ] ) .
this choice is justified from the physical point of view because those parts of the scales @xmath218 are exactly responsible for the power corrections @xmath219 to the form factor @xmath2 which we are going to compute .
the next problem then is how to generalize eqs .
( [ eq:2.21 ] ) and ( [ eq:2.22 ] ) in such a way so that the corresponding hard - scattering amplitudes @xmath220 and the quark and gluon components of the vertex function will obey eqs .
( [ eq:2.25]-[eq:2.31 ] ) .
for this purpose , we symmetrize the functions @xmath221 by exchanging @xmath222 to obtain @xmath223\ ] ] @xmath224 @xmath225\ ] ] @xmath226 and @xmath227\ ] ] @xmath228 \frac{(1+\omega ) x+(1-\omega ) \overline{x}}{\omega \left [ ( 1+\omega ) \overline{x}+(1-\omega ) x \right ] } , \ ] ] @xmath229\ ] ] @xmath230 \frac{(1+\omega ) \overline{x}+(1-\omega ) x } { \omega \left [ ( 1+\omega ) x+(1-\omega ) \overline{x } \right ] } .\ ] ] in the `` frozen '' coupling - constant approximation @xmath231 , eqs .
( [ eq:2.33 ] ) and ( [ eq:2.34 ] ) coincide with expressions ( [ eq:2.21 ] ) and ( [ eq:2.22 ] ) .
it is also not difficult to verify that the hard - scattering amplitudes @xmath232 ( [ eq:2.33 ] ) , ( [ eq:2.34 ] ) satisfy eqs .
( [ eq:2.25 ] ) and ( [ eq:2.26 ] ) . as a result , eqs .
( [ eq:2.27])-([eq:2.31 ] ) remain valid also within the rc method .
the important input information needed for the computation of the form factor @xmath233 are the da s of the quark and gluon components of the @xmath1 meson , namely , the functions @xmath234 and @xmath235 . in general , a meson da is a function containing all nonperturbative , long - distance effects , which can not be calculated by employing perturbative qcd tools .
its dependence on @xmath67 ( or its shape ) has to be deduced from experimental data or found using some nonperturbative methods , for example , qcd sum - rules ( see , e.g. , @xcite ) .
in contrast , the evolution of the da with the factorization scale @xmath61 is governed by pqcd .
the evolution equation for the da of a flavor singlet pseudoscalar meson was derived and solved in refs .
it turned out that due to mixing of the quark - antiquark and two - gluon components of the meson da , the evolution equation has a @xmath236 matrix form .
the anomalous dimensions matrix , which enters into the evolution equation at the one - loop order , has the following components @xcite ( see also ref .
@xcite ) @xmath237 , \,\,\,\gamma _ { gg}^n = n_c\left [ \frac{\beta _ 0}{n_c}+\frac 8{(n+1)(n+2)}-4\sum_{j=1}^{n+1}\frac 1j\right ] , \ ] ] @xmath238 where @xmath239 and @xmath240 is the group theoretical factor for @xmath241 .
the anomalous dimensions matrix has the eigenvalues @xmath242 .\ ] ] the solutions of the evolution equation for the quark and gluon components of the da has , in general , the form @xmath243 c_n^{3/2}(x- \overline{x})\right\}\ ] ] and @xmath244 c_{n-1}^{5/2}(x- \overline{x})\ ] ] with the constant @xmath245 being defined as @xmath246 in eqs .
( [ eq:2.37 ] ) and ( [ eq:2.38 ] ) @xmath247 and @xmath248 are gegenbauer polynomials , calculable using the recurrence formula @xcite @xmath249 @xmath250 the parameters @xmath251 and @xmath252 are determined in terms of the anomalous dimensions matrix elements @xmath253 in eqs .
( [ eq:2.37 ] ) and ( [ eq:2.38 ] ) @xmath254 is the normalization point , at which the free input parameters @xmath255 in the da s @xmath234 and @xmath235 have to be fixed .
exactly these parameters determine the shape of the da s . for all @xmath256 , the eigenvalues @xmath257 and
their absolute values increase with @xmath258 .
hence , in the asymptotic limit @xmath259 , one has @xmath260 and therefore only the quark component of the @xmath110 meson da survives , evolving to its asymptotic form , whereas the gluon da in this limit vanishes , @xmath261 in this work , we shall use the @xmath1-meson da that contains only the first non - asymptotic terms .
in other words , we suggest that in eqs .
( [ eq:2.37 ] ) and ( [ eq:2.38 ] ) @xmath262 and @xmath263 for all @xmath264 .
the numerical values of the relevant parameters for @xmath265 are @xmath266 @xmath267 taking into account eq .
( [ eq:2.42 ] ) and the expressions for the required gegenbauer polynomials @xmath268 = 6\left ( 1 - 5x\overline{x}\right ) , \,\,\,\,c_1^{5/2}(x-\overline{x})\,=5(x-\overline{x}),\ ] ] we finally recast the @xmath1 meson quark and gluon da s into the more suitable ( for our purposes ) forms @xmath269 , \,\,\,\,\,\,\,\phi ^g(x , q^2 ) = cx\overline{x}(x-\overline{x})b(q^2).\ ] ] in these expressions the functions @xmath270 and @xmath271 are defined by @xmath272 @xmath273 the @xmath1 meson quark and gluon da s for @xmath274 are given in the appendix .
equations ( [ eq:2.43 ] ) , ( [ eq:2.44 ] ) , and ( [ eq:1app ] ) contain all necessary information about the singlet part of the @xmath1 meson da .
0 to compute the @xmath1-meson virtual - gluon transition form factor @xmath275 , we have to perform in eqs .
( [ eq:2.16 ] ) and ( [ eq:2.17 ] ) the integration over @xmath67 by inserting the explicit expressions for the hard - scattering amplitudes @xmath276 and the @xmath1-meson quark and gluon da s , and retain the @xmath67-dependence of the coupling @xmath277 [ @xmath278 . such calculations lead to divergent integrals because the running coupling @xmath277 [ @xmath278 suffers from an infrared singularity in the limit @xmath279 [ @xmath280 .
this means that in order to carry out computations with the running coupling , some procedure for its regularization in the end - point @xmath281 regions has to be adopted . as a first step in this direction , we express the running coupling @xmath282 in terms of @xmath211 , employing the renormalization - group equation @xmath283 ^2-\frac{\beta _ 1 } { 8\pi ^2}\left [ \alpha_{\rm s}(q^2 x ) \right ] ^3.\ ] ] the solution of eq .
( [ eq:3.1 ] ) , obtained by keeping the leading @xmath284 and next - to - leading @xmath285 powers of @xmath286 , reads @xcite @xmath287}{1+\ln x /t}\right ] , \ ] ] where @xmath211 is the one - loop qcd coupling constant and @xmath288 .
inserting eq .
( [ eq:3.2 ] ) into the expressions for the hard - scattering amplitudes and subsequently @xmath289 into eqs .
( [ eq:2.16 ] ) and ( [ eq:2.17 ] ) , we obtain integrals which are still divergent , but which now can be calculated using existing methods .
one of these methods , applied in ref .
@xcite for the calculation of the electromagnetic pion form factor , allows us to find the quantity under consideration as a perturbative series in @xmath211 with factorially growing coefficients @xmath290 .
similar series with coefficients @xmath290 may be found also for the form factor @xmath291 , i.e. , @xmath292^n\beta_0^{n-1}c_n.\ ] ] but a perturbative qcd series with factorially growing coefficients is a signal for the ir renormalon nature of the divergences in eq .
( [ eq:3.3 ] ) .
the convergence radius of the series ( [ eq:3.3 ] ) is zero and its resummation should be performed by employing the borel integral technique .
first , one has to find the borel transform @xmath293(u)$ ] of the corresponding series @xcite @xmath294 ( u)=\sum_{n=1}^\infty \frac{u^{n-1}}{(n-1)!}c_n.\ ] ] because the coefficients of the series ( [ eq:3.3 ] ) behave like @xmath290 , the borel transform ( [ eq:3.4 ] ) contains poles located at the positive @xmath295 axis of the borel plane . in other words ,
the divergence of the series ( [ eq:3.3 ] ) owing to eq .
( [ eq:3.4 ] ) has been transformed into pole - like singularities of the function @xmath296(u)$ ] .
these poles are the footprints of the ir renormalons . now in order to define the sum ( [ eq:3.3 ] ) or to find the resummed expression for the form factor , one has to invert @xmath297(u)$ ] to get @xmath298 ^{res}\sim p.v.\int_0^\infty du\exp \left [ -\frac{4\pi } { \beta _ 0\alpha_{\rm s}(q^2)}u\right ] b\left [ q^2f_{\eta ^{\prime } g^{*}g^{*}}\right ] ( u)\ ] ] and remove the ir renormalon divergences by the principal value prescription . the procedure described above , is straightforward but , at the same time , tedious .
fortunately , these intermediate operations can be bypassed by introducing the inverse laplace transforms of the functions in eq .
( [ eq:3.2 ] ) @xcite , viz .
, @xmath299u^{\nu -1},\,\,\,\,\,\,\,re\nu > 0\ ] ] and @xmath300(1-\gamma _ e-\ln u)u,\,\,\,\,\,\,\,\ ] ] where @xmath301 is the gamma function , @xmath302 is the euler constant , and @xmath303 [ or @xmath304 . then using eqs . ( [ eq:3.2 ] ) , ( [ eq:3.6 ] ) and ( [ eq:3.7 ] ) for @xmath305 , we get @xcite @xmath306 with the function @xmath307 defined as @xmath308 employing eq .
( [ eq:3.8 ] ) for @xmath305 and carrying out the integrations over @xmath67 , we obtain ( see , the next section ) the quark and gluon components of the form factor @xmath309 directly in the borel resummed form ( [ eq:3.5 ] ) .
the resummed vertex function @xmath310^{res}$ ] - except for the @xmath110-meson on - shell - gluon transition and the @xmath177 case - contains an infinite number of ir renormalon poles located at @xmath311 , where @xmath258 is a positive integer that , in general , is given as a sum of a series , i.e. , @xmath312 one appreciates that all information on the process asymmetry parameter @xmath151 is accumulated in the coefficient functions @xmath313 . to avoid inessential technical details and to make the presentation as transparent as possible ,
let us for the time being neglect the non - leading term @xmath314 in eq .
( [ eq:3.2 ] ) and make the replacement @xmath315 in eq .
( [ eq:3.10 ] ) .
then , the integrals in eq .
( [ eq:3.10 ] ) take , after simple manipulations , the form @xmath316 with the logarithmic integral @xmath317 defined by @xmath318 the function @xmath317 is expressible in terms of the function @xmath319 @xcite @xmath320 where @xmath321 the latter expression can , for @xmath322 , be expanded over inverse powers of @xmath323 @xmath324 .\ ] ] using eqs .
( [ eq:3.13 ] ) and ( [ eq:3.14 ] ) , we find @xmath325 it is not difficult to see that for @xmath326 @xmath327^m\beta _ 0^{m-1 } \frac{(m-1)!}{n^m}.\ ] ] choosing in eq .
( [ eq:3.16 ] ) @xmath328 and comparing the obtained result with eq .
( [ eq:3.3 ] ) , we conclude that each term in the sum ( [ eq:3.10 ] ) at fixed @xmath258 is the resummed borel expression of the series ( [ eq:3.16 ] ) .
but we can look at the integrals in eq .
( [ eq:3.10 ] ) from another perspective .
namely , it is easy to show that @xmath329 where @xmath330 are the moment integrals @xmath331 the integrals @xmath332 can be calculated using the ir matching scheme @xcite @xmath333 ^n\left [ n!-\gamma \left ( n+1,\,\,p\ln ( q/\mu_i ) \right ) \right ] , \ ] ] where @xmath334 is the infrared matching scale and @xmath335 is the incomplete gamma function @xmath336 in eq .
( [ eq:3.19 ] ) @xmath337 are phenomenological parameters , which represent the weighted average of @xmath338 over the ir region @xmath339 and act at the same time as infrared regulators of the r.h.s . of eq .
( [ eq:3.17 ] ) . the first term on the r.h.s . of eq .
( [ eq:3.19 ] ) is a power - suppressed contribution to @xmath332 , which can not be calculated within pqcd , whereas the second term is the perturbatively calculable part of the function @xmath332 .
stated differently , the infrared matching scheme allows one to estimate power corrections to the moment integrals by explicitly dissecting them from the full expression and introducing new nonperturbative parameters @xmath337 .
the values of these parameters have to be extracted form experimental data .
in order to check the accuracy of both the rc method ( ir renormalon calculus ) and the infrared matching scheme , a landau - pole free model for @xmath211 was introduced in ref .
@xcite yielding @xmath340.\ ] ] the model expression ( [ eq:3.21 ] ) was used for the exact calculation of the moment integrals @xmath341 .
the ir renormalon and the ir matching scheme results were compared with @xmath341 concluding that for @xmath342 the ir matching scheme leads to a good agreement with the exact values of @xmath332 . as regards the calculation of the integrals @xmath332 , when employing the rc method with the principal value prescription , a good agreement with @xmath343 was found for @xmath344 , while for @xmath345 a small deviation from @xmath346 in the region of @xmath347 a few @xmath348 was observed ( the lowest moment integral entering into our expressions is @xmath349 ) .
but even for @xmath345 , the agreement with @xmath346 within the error bars is quite satisfactory in view of the uncertainties produced by the principal value prescription itself .
therefore , we can conclude that the rc method and the ir matching scheme lead for the moment integrals @xmath332 to approximately similar numerical results .
it is remarkable that in both cases an enhancement of the ir renormalon and matching - scheme results relative to the leading - order perturbative prediction was found . after presenting our analysis ,
it becomes evident that the borel resummation technique enables us to estimate with a rather good accuracy power - behaved corrections to the integrals in eq .
( [ eq:3.10 ] ) and hence to the vertex function @xmath56 .
of course , one can employ the ir matching scheme and eq .
( [ eq:3.19 ] ) to determine power corrections to the form factor in explicit form .
but as we have noted above , in general , the form factor @xmath291 contains an infinite number of ir renormalon poles or stated equivalently , an infinite number of @xmath330 is required to calculate sums like the one presented in eq .
( [ eq:3.10 ] ) . in real numerical computations ,
in order to reach a good approximation of the series ( [ eq:3.10 ] ) , at least a sum of the first @xmath350 terms is needed , meaning the involvement of @xmath351 ( @xmath352 ) nonperturbative parameters .
but from the experimental data , only the first few moments @xmath353 could be extracted @xcite .
values for @xmath354 ( in the literature the notation @xmath355 is widely used ) range from @xmath356 @xcite and @xmath357 @xcite to @xmath358 @xcite . here
, we write down only sample results , obtained in these works , in order to demonstrate the experimental situation with @xmath359 . for @xmath360 the value @xmath361 was deduced @xcite from the data on structure functions @xcite . in the framework of the rc method
, we estimate the same power corrections to a physical quantity , but here we do not need additional information on @xmath353 .
moreover , this method gives us the possibility to calculate values of the nonperturbative parameters @xmath337 by means of the formula @xmath362 that can be easily found by comparing eqs .
( [ eq:3.11 ] ) and ( [ eq:3.17 ] ) .
the calculated values of the first few even moments ( @xmath363 ) are @xmath364 to compare our predictions with those computed via the model @xmath211 ( eq . ( [ eq:3.21 ] ) ) , we choose @xmath265 and @xmath365 .
the corresponding values are shown below @xmath366 one observes that the parameters @xmath367 of the rc method are in agreement with both the experimental results and the model calculations . we have noted above that the principal value prescription , adopted in this work in order to regularize divergent integrals ( see , eqs .
( [ eq:3.5 ] ) , ( [ eq:3.10 ] ) ) generates power - suppressed ( higher - twist ) uncertainties @xmath368 where @xmath369 are calculable functions entirely fixed by the residues of the borel transform @xmath370(u)$ ] at the poles @xmath371 and @xmath372 are arbitrary constants to be fixed from experimental data . in the case of the @xmath15 electromagnetic transition form factor @xmath373 ,
the uncertainties ( [ eq:3.25 ] ) were estimated in ref .
@xcite . for the @xmath1 meson asymptotic da and for the parameters @xmath374 and @xmath375
, it was found that they do not exceed @xmath376 of the @xmath15 form factor . because the rc method allows one to evaluate power corrections to a physical quantity , in general , and for the @xmath377 transition form factor it has already provided a good agreement with the cleo data @xcite
, one has to introduce the constraint @xmath378 in order to retain this agreement . in the present work we shall estimate in our numerical analysis the higher - twist uncertainties produced by the principal value prescription by choosing the constants @xmath379 .
it will be demonstrated that the @xmath376 bounds are valid also for the @xmath380 transition ff s .
inclusion of higher - twist corrections , arising from the two particle higher - twist and higher fock states da s of the @xmath1 meson , may , in principle , further improve this scheme .
these refinements are , however , beyond the scope of the present investigation .
0 in this section we calculate the quark and gluon components of the vertex function @xmath382 within the rc method .
we also present our results for @xmath383 , @xmath4 and the asymptotic limit for the form factor . to calculate the quark component of the vertex function @xmath385 , we use eq .
( [ eq:2.27 ] ) for @xmath386 , eq .
( [ eq:2.33 ] ) for the hard scattering amplitude @xmath387 , and the expression for @xmath282 given in eq .
( [ eq:3.8 ] ) . employing the quark component of the @xmath110-meson da , @xmath388
, we get have to be understood in the sense of the cauchy principal value . ]
@xmath389}{\beta _ 0}\int_0^\infty due^{-ut}r(u , t)\ ] ] @xmath390\ ] ] @xmath391 @xmath392 .\ ] ] using the fact that the integral @xcite @xmath393 is expressible in terms of the gauss hypergeometric function @xcite @xmath394 we obtain @xmath395}{\beta_0(1+\omega ) } \int_{0}^{\infty}due^{-ut}r(u , t)b(2-u,2)\ ] ] @xmath396\ ] ] @xmath397 @xmath398.\ ] ] in eqs .
( [ eq:4.2 ] ) and ( [ eq:4.3 ] ) , @xmath399 and @xmath400 are the beta function and pochhammer symbols , respectively , defined in terms of the gamma function @xmath301 @xmath401 from eq .
( [ eq:4.4 ] ) a simple expression for the @xmath1-meson on - shell - gluon transition form factor @xmath402 can be found @xmath403}{\beta _
0}\int_0^\infty due^{-ut}r(u , t)\left [ b(1,2-u)\right.\ ] ] @xmath404+\frac{80\pi ^2ca(q^2)}{\beta _ 0 } \int_0^\infty due^{-ut}r(u , t)\left [ b(3,2-u)+b(2,3-u)\right ] , \ ] ] where we have used the equality @xcite
@xmath405 it is worth noting that eq .
( [ eq:4.7 ] ) can be obtained from eq .
( [ eq:2.27 ] ) by employing the @xmath406 limits of the hard scattering amplitudes ( [ eq:2.33 ] ) @xmath407 \left[\frac 1 { x}+\frac 1 { \overline{x}}\right ] .\ ] ] in the case of gluons with equal virtualities @xmath155 ( and hence in the @xmath408 case ) , the form factor can be found employing the expression for the hard - scattering amplitude @xmath409.\ ] ] calculation leads to the simple expression @xmath410 @xmath411 let us note that eq .
( [ eq:4.11 ] ) can be deduced from eq .
( [ eq:4.4 ] ) in the limit @xmath412 by taking into account that @xcite @xmath413 the next important problem to be solved within the framework of the rc method , is to reveal the ir renormalon poles in eqs .
( [ eq:4.4 ] ) , ( [ eq:4.7 ] ) and ( [ eq:4.11 ] ) because without such a clarification all these expressions would have merely a formal character .
we start from the simple case , i.e. , from eq .
( [ eq:4.7 ] ) , and get @xmath414 @xmath415 and @xmath416 @xmath417 in deriving these expressions we used the following property of the gamma function @xmath418 hence we have @xmath419}{\beta _
0}\int_0^\infty e^{-ut}r(u , t)\frac{du}{1-u}\ ] ] @xmath420 as one sees , the structure of the ir renormalon poles is very simple ; we encounter only a finite number of single poles located at @xmath421 and @xmath422 . in the same manner
we get from eq .
( [ eq:4.11 ] ) @xmath423 @xmath424 in this case the single ir renormalon poles are located at the points @xmath425 and @xmath426 . in order to get the ir renormalon structure of the integrands in eq .
( [ eq:4.4 ] ) , we have to expand the hypergeometric function @xmath427 in powers of @xmath323 ( see eq .
( [ eq:4.3 ] ) ) , where the condition @xmath428 must hold .
but the argument of the function @xmath429 satisfies this requirement only in the region @xmath430 . in the region
@xmath431 an expression obtained from ( [ eq:4.4 ] ) by means of a simple transformation ( see , ( [ eq:4.18a ] ) below ) has to be used because in this case the argument of the hypergeometric function becomes equal to @xmath432 , obeying in the region @xmath433 the required constraint . but
regardless of the expansion region , we obtain in both cases the same ir renormalon structure . adding to this argumentation the evident fact that the vertex function is symmetric under the replacement @xmath55 ( cf .
( [ eq:2.31 ] ) ) , we can restrict the study of the form factor @xmath434 to the region @xmath430 . then , we can expand the hypergeometric functions @xmath429 in the region @xmath430 , via eq .
( [ eq:4.3 ] ) .
for example , for one of these functions , we get @xmath435 @xmath436 with @xmath437 the remaining terms in eq .
( [ eq:4.4 ] ) can be treated in the same manner and as a result we obtain @xmath389}{\beta _ 0(1+\omega ) } \int_0^\infty due^{-ut}r(u , t)\ ] ] @xmath438 \beta^k\ ] ] @xmath439\beta^k.\ ] ] the ir renormalon structure of the integrands in eq .
( [ eq:4.14 ] ) is quite clear now .
in fact , we can write the beta functions entering eq .
( [ eq:4.14 ] ) in the following form @xmath440 and correspondingly @xmath441 @xmath442 @xmath443 here we have an infinite number of single ir renormalon poles located at the points @xmath444 and @xmath445 , respectively . the last question to be answered is , whether one can use our results , obtained in the context of the rc method , in the limit @xmath446 in order to regain the asymptotic form of the form factor @xmath447 .
it is clear that regardless of the methods employed and the approximations done , in the limit @xmath259 the form factor @xmath448 must reach its asymptotic form .
this is true , of course , for our computations , as we estimate power - suppressed corrections to the form factor @xmath449 , which become important in a region of @xmath347 of a few gev@xmath450 , but vanish in the asymptotic limit . as we have emphasized in sect .
ii , in the asymptotic limit the gluon da of the @xmath451-meson satisfies @xmath452 and hence @xmath453 the da of the quark component @xmath388 of
the @xmath1 meson evolves for @xmath454 to the asymptotic da ( [ eq:2.41 ] ) and all non - asymptotic terms in @xmath388 proportional to @xmath455 ( in our case @xmath456 ) vanish .
therefore , the results , which we shall obtain here , describe not only the asymptotic limit of @xmath434 , but also the asymptotic limit of the vertex function @xmath2 itself . in the limit @xmath457 the asymmetry parameter can take values @xmath458
( if we pass to the limit @xmath259 at fixed @xmath459 or @xmath460 ) , @xmath408 ( @xmath155 and @xmath457 ) or @xmath461 ( if we take the limit @xmath259 at fixed @xmath151 ) . we consider here all possibilities : a ) @xmath462 , b ) @xmath463 and c ) @xmath464 . in the limit @xmath259
, we also take into account that the second term in the expansion @xmath305 ( [ eq:3.8 ] ) has to be neglected . in other words , in the limit @xmath259 , we find @xmath465 we begin from the simpler case a ) . in eq .
( [ eq:4.12 ] ) we have already obtained the desired limit , but @xmath466 . taking into account eq .
( [ eq:4.15 ] ) and @xmath467 , we get @xmath468 it is easy to show that using only the leading term in the expansion of @xmath469 ( see , eq .
( [ eq:3.15 ] ) ) , we find @xmath470 the limit @xmath463 can be analyzed by similar means .
thus , from eq .
( [ eq:4.13 ] ) we get @xmath471 @xmath472,\ ] ] which in the limit under consideration simplifies to @xmath473 now let us consider the more interesting case c ) . then , from eqs
. ( [ eq:4.4 ] ) and ( [ eq:4.15 ] ) , we obtain @xmath474 @xmath475 .\ ] ] as an example , we analyze the second term in eq .
( [ eq:4.18 ] ) ( see also eq .
( [ eq:4.14 ] ) ) @xmath476 @xmath477 \beta ^k.\ ] ] in the considered limit , one finds @xmath478 then , the result reads @xmath479 \beta ^k\rightarrow \frac 1{\ln \lambda } \sum_{k=0}^\infty \frac{\gamma ( 2)}{(k+2)(k+3)}\beta^k\ ] ] @xmath480 the same method can be applied to the first function in eq .
( [ eq:4.18 ] ) .
but before doing that , it is instructive to employ the transformation @xmath481 after performing all these operations we find @xmath482 @xmath483 taking into account the expression for the hypergeometric function @xmath484 in terms of elementary ones @xcite @xmath485 , \ ] ] we finally obtain @xmath486 in our argumentations we have tacitly assumed that @xmath430 .
but eq . ( [ eq:4.21 ] ) holds for all values of @xmath461 , which is evident from the equality @xmath487 .
equations ( [ eq:4.16 ] ) , ( [ eq:4.17 ] ) and ( [ eq:4.21 ] ) can be obtained in the standard hsa using the corresponding hard - scattering amplitudes ( [ eq:4.9 ] ) , ( [ eq:4.10 ] ) and ( [ eq:2.21 ] ) .
the analysis carried out so far proves the correctness of the rc method leading to the expected expressions for the form factor @xmath291 at @xmath259 and demonstrating at the same time the consistency of the symmetrization of the hard - scattering amplitudes ( [ eq:2.33 ] ) , ( [ eq:2.34 ] ) .
the contribution of the gluon component of the @xmath110-meson to the form factor @xmath148 can be computed using the methods described in the previous subsection .
using eq .
( [ eq:2.34 ] ) for the hard - scattering amplitude @xmath488 , eq .
( [ eq:2.28 ] ) and the gluon component of the @xmath1-meson da , we have for the gluon part of the form factor @xmath489 @xmath490 } + \int_{0}^{1}dxx\overline{x}^{1-u}(x-\overline{x } ) \frac{(1+\omega)x+(1-\omega)\overline{x}}{\omega \left [ ( 1+\omega)\overline{x}+(1-\omega)x \right ] } \right ] , \ ] ] which after some simple calculations becomes @xmath491 @xmath492 @xmath493\ ] ] @xmath494 \right\ } .\ ] ] for the @xmath110-meson on - shell - gluon transition , we find @xmath495 @xmath496 , \ ] ] or equivalently @xmath497 the form factor @xmath498 can be calculated by employing the following form for the hard - scattering amplitude @xmath499 \frac{x-\overline{x}}{1-\omega^2(x-\overline{x})^2},\ ] ] which for @xmath408 leads to a very simple expression .
then , it is not difficult to demonstrate that @xmath500 @xmath501.\ ] ] this latter expression can be recast into the form @xmath502 @xmath503.\ ] ] the ir renormalon structure of the integrands in eq .
( [ eq:4.26 ] ) and ( [ eq:4.29 ] ) is obvious : they have a finite number of ir renormalon poles located at the points @xmath504 and @xmath505 , respectively . in order to find the ir renormalon structure of the integrand in eq .
( [ eq:4.23 ] ) , we expand the corresponding hypergeometric functions over @xmath506 in the region @xmath430 , providing the following result @xmath507 @xmath508 \beta ^k-\frac{1-\omega } { 1+\omega } \left [ b(k+2,4-u)+b(k+2-u,4)\right ] \beta ^k\ ] ] @xmath509 \beta ^{k+1}\right\}.\ ] ] using the identities @xmath510 @xmath511 @xmath512 @xmath513 @xmath514 @xmath515 it is easy to conclude that there is an infinite number of ir renormalon poles , being located at the points @xmath516 ; @xmath517 ; @xmath518 ; @xmath519 ; @xmath520 and @xmath521 .
0 we begin this section by comparing the results obtained with the rc method with those from the ir matching scheme . in sect .
iii we have noted that from experimental data only values of the nonperturbative parameters @xmath522 and @xmath523 have been extracted .
we also know that the lowest - order moment integral and hence the parameter entering our formulas is @xmath523 . therefore , to make the comparison as clear as possible
, we should choose the input parameters for the @xmath1-virtual gluon transition in such a way as to determine the behavior of the form factor solely with @xmath523 .
this can be easily achieved if we set for the @xmath1-meson da parameters @xmath524 under these circumstances , the gluon component of the vertex function vanishes . to remove from the analysis the higher - moment integrals @xmath525
, we consider only the @xmath1-meson on - shell - gluon transition , i.e. , the @xmath526 case .
moreover , we neglect the @xmath527 order term in eq .
( [ eq:3.2 ] ) and set in eq .
( [ eq:3.8 ] ) @xmath528 because in eq .
( [ eq:3.19 ] ) @xmath529 is used at the level of the one - loop order accuracy .
after these simplifications , the ff is given by the following expression @xmath530 results of our computations are shown in fig .
[ fig : gfig3 ] , where in order to distinguish the various curves , these are displayed in the region of @xmath531 $ ] gev@xmath532 , whereas at higher @xmath61 they are close to each other .
the rc method and the ir matching scheme ) with @xmath533 has been used . ] both lead almost to identical predictions in the entire domain @xmath534 , provided that in the ir matching scheme one uses in expression ( [ eq:3.19 ] ) the value @xmath535 found within the rc method ( [ eq:3.23 ] ) .
the curve following from the ir matching scheme deviates from the prediction obtained with the rc method only for @xmath536 . on the other hand ,
the deviation of that curve , calculated using the experimental value @xmath537 , from the result of the rc method is sizeable in the region @xmath538 , reaching @xmath539 at @xmath540 .
a similar behavior was observed in the calculation of the pion electromagnetic form factor , carried out within the context of these methods @xcite .
the difference between the solid and the dot - dashed lines in fig .
[ fig : gfig3 ] is considerably reduced when varying the qcd scale parameter @xmath541 or the experimental value of @xmath523 within their corresponding uncertainty limits .
but we are not going to make decisive conclusions from these rather model - dependent calculations .
our aim here is to check and demonstrate that the rc method and the ir matching scheme predict in the considered region @xmath542 almost identical results that do not contradict experiment . in order to proceed with the computation of the @xmath1-meson gluon vertex function and
explore the role played by the @xmath1 gluon content in this process , we have to define the allowed values of the free input parameters @xmath543 and @xmath544 at the normalization point @xmath545 .
these parameters determine the shape of the da s of the quark and gluon components of the @xmath1-meson and , in general , they have to be extracted from experimental data or computed by non - perturbative techniques .
the comparison of the @xmath1-meson photon electromagnetic transition ff @xmath546 with the cleo data leads to the conclusion that the @xmath1-meson da must be close to its asymptotic form with a coefficient @xmath547 deduced in @xcite . but this conclusion was made by neglecting the contribution of the gluon component of the @xmath1-meson to the @xmath15 transition ff .
the investigation of the ff @xmath546 was extended and revised in @xcite .
in fact , in this work the ff @xmath546 was computed within the rc method by taking into account contributions arising due to both the quark and gluon components of the @xmath1 meson da .
the comparison with the cleo data demonstrated that allowed values of the gegenbauer coefficients @xmath548 and @xmath549 are strongly correlated .
they were extracted in ref .
@xcite and read @xmath550,\ ] ] @xmath551,\ ] ] and @xmath552.\ ] ] in the present paper we select values of the parameters @xmath548 and @xmath549 that obey the constraints ( [ eq:5.1a ] ) and ( [ eq:5.1b ] ) . it is evident that the non - asymptotic terms in the quark and gluon da s of the @xmath1-meson proportional to @xmath270 and @xmath271 , respectively , affect the asymptotic value of the @xmath1-meson - gluon transition form factor .
therefore , before presenting contributions from these terms , it is instructive to study the asymptotic ff itself . in the left panel of fig .
[ fig : gfig4 ] , we depict the @xmath1-meson - virtual gluon transition ff as a function of the gluon virtuality @xmath61 . for the asymptotic da the quark component of the form factor
coincides with the full one . in the same figure
the predictions obtained within the standard hsa are also shown .
one sees that in the domain @xmath553 the standard pqcd results get enhanced by approximately a factor of two due to power corrections .
a similar conclusion is valid also for the gluon component of the form factor ( right panel in fig .
[ fig : gfig4 ] , computed by employing the @xmath1-meson da s ) . here
some comments concerning the accuracy of the numerical computations are in order . in fig .
[ fig : gfig4 ] ( left panel ) and in the following ones , the curves obtained within the rc method , as a rule , require a summation of an infinite series . in real numerical computations
we truncate such a series at some @xmath554 .
naturally , the question arises about the convergence rate of this series .
let us explain this problem by considering fig .
[ fig : gfig4 ] as an example .
the solid curve with @xmath555 in fig .
[ fig : gfig4 ] ( left panel ) has been found within the rc method by employing eq .
( [ eq:4.14 ] ) .
this expression contains a series with factorially growing coefficients .
for definiteness we analyze the term @xmath556
@xmath557 the expansion parameter @xmath558 in eq .
( [ eq:5.2 ] ) at the point @xmath555 is equal to @xmath559 .
below , we write down the values of the gamma function @xmath560 and also those of the product of @xmath561 with the principal value of the integral @xmath562 for @xmath563 , @xmath426 and @xmath564 @xmath565 and @xmath566 as a result , the corresponding terms in the sum given by eq .
( [ eq:5.2 ] ) take the values @xmath567 respectively .
the calculations above have been performed at @xmath568 . at the momentum transfer @xmath569
we get @xmath570 one observes that the convergence rates of the numerical series are high and that we can therefore truncate them , as a rule , at @xmath571 .
we have analyzed the impact of the various da s of the @xmath1-meson on the @xmath572 transition form factor .
the quark component of the ff is stable for different values of @xmath573 $ ] .
it is difficult to distinguish the corresponding curves and therefore in fig .
5a we can only plot some of them .
in contrast , the gluon component of the form factor demonstrates a rapid growth with @xmath544 ( fig .
5b ) . as a result , due to different signs of the quark and gluon components of the space - like vertex function , the total vertex function @xmath574 for @xmath575 lies below the asymptotic one ( fig .
6a ) . comparing the predictions derived within the rc method with those following from the standard hsa ( fig .
6b ) , we see a quantitative difference between corresponding curves .
the dependence of the quark and gluon components of the form factor on the asymmetry parameter @xmath149 at fixed @xmath61 and for various da s of the @xmath1-meson are shown in fig .
[ fig : gfig7 ] . because @xmath56 is symmetric under the exchange @xmath55 , we present our results in the region @xmath576 only .
we have just demonstrated in fig .
[ fig : gfig5 ] that the quark component of the ff @xmath577 is not sensitive to the use of various @xmath1-meson da s , employed in our calculations .
this is valid also for its behavior as a function of @xmath149 ( fig .
in accordance with our computations , an effect of the chosen parameter @xmath544 on the gluon component of the ff is considerable in the whole range of @xmath578 $ ] .
the magnitude of the quark and gluon components of the form factor for a given da depends on the total gluon virtuality @xmath61 ( fig .
[ fig : gfig8 ] ) . in this case
both the quark and gluon contributions to the ff demonstrate sensitivity to the fixed value of @xmath61 . the features of the quark and gluon components of the @xmath72 transition
ff described above determine the behavior of their sum as a function of the asymmetry parameter @xmath149 and , as a result , we get the picture shown in fig .
owing to the gluon component , the form factor @xmath56 depends on the @xmath1-meson da used in the calculations . for comparison , in fig .
9b the curves found within the standard hsa are also shown .
an enhancement of about a factor of two of the vertex function due to power corrections is evident .
the @xmath72 transition ff as function of the first gluon virtuality @xmath579 at various fixed values of the second one , @xmath459 , and for different da s is plotted in fig . [
fig : gfig10 ] . as we have noted in sect .
iii , the principal value prescription , adopted in this work to regularize divergent integrals , produces higher - twist ambiguities .
it is important to clarify to what extent these ambiguities may alter our predictions . to illustrate this effect ,
we depict in fig .
[ fig : gfig11 ] , as an example , the scaled @xmath572 transition ff @xmath574 . the higher - twist ambiguities lead approximately to @xmath376 shifts relative to the previous rc result ( line @xmath580 ) . on the other hand , comparing the standard pqcd prediction ( solid line 1 ) with the lower dashed line ( that denotes the rc prediction with a negative higher - twist ambiguity ) , we see that still the power corrections provide an enhancement of the standard pqcd result by a factor @xmath581 in the region @xmath582 and by a factor @xmath583 at @xmath584 .
this latter effect is connected not only to larger uncertainties , but also reflects the general trend of the ff to reach its asymptotic value , i. e. , the line @xmath585 in the limit @xmath457 .
in this paper we have evaluated power - suppressed corrections @xmath586 to the space - like @xmath1-meson virtual - gluon transition form factor @xmath587 . to this end , we have employed the standard hard - scattering approach and the running - coupling method in conjunction with the infrared - renormalon calculus . in the calculations , both the quark and the gluon distribution amplitudes of the @xmath1 meson
have been taken into account . in these model da s only the first non - asymptotic terms
have been retained and the values of the input coefficients @xmath588 and @xmath589 extracted from the analysis of the cleo data on the @xmath15 electromagnetic transition ff have been employed . in order to apply the rc method to the considered process , the hard - scattering amplitudes of the corresponding subprocesses have been generalized in such a way as to preserve the symmetry properties of both the hard - scattering amplitudes and the transition form factor itself under the replacements @xmath590 and @xmath591 . in the computations within the rc method ,
the laplace transformed expression for the running coupling has been employed .
the borel resummed form factors , obtained this way , have been regularized by means of the principal value prescription .
various limits of the general expression @xmath587 have been found .
our expressions for the vertex function @xmath56 , found within the standard hsa , are in agreement with corresponding predictions made in ref .
@xcite ( up to a conventional sign factor ) .
it has been demonstrated that ( see eq .
( [ eq:2.31 ] ) ) both the quark and the gluon components of the vertex function are symmetric under the exchange @xmath55 , as they must be owing to the bose symmetry of the final gluons .
the rc method has provided us a tool for estimating power corrections to the vertex function @xmath56 .
these corrections are implicitly contained in the pqcd factorization formulas ( [ eq:2.16 ] ) , ( [ eq:2.17 ] ) and originate from the end - point @xmath592 regions .
it is clear that such corrections can not been taken into account in the standard pqcd approach by freezing the renormalization scale @xmath593 and ignoring its dependence on the longitudinal momentum fraction @xmath67 . as an important consistency check
, we have proven that the results obtained with the rc method in the asymptotic limit @xmath457 reproduce the standard pqcd predictions for the vertex function .
this provides further justification for the treatment of the hard - scattering amplitudes ( [ eq:2.33 ] ) , ( [ eq:2.34 ] ) , and the symmetrization procedure employed in the running coupling method .
the presented numerical analysis shows that power corrections considerably enhance the standard pqcd predictions for the form factor in the explored region @xmath594 , though other sources , not considered here , may also give rise to power corrections .
our investigations demonstrate that the quark component of the form factor at fixed @xmath595 is practically stable for several values of @xmath596 .
contrary to this , the gluon component of the ff is sensitive to the adopted value of @xmath544 . as a consequence
, the @xmath72 transition ff was found to depend on the gluonic content of the @xmath1 meson . in the considered region
the gluon contribution reduces the absolute value of the space - like form factor @xmath587 . as is true of any technique for calculating power corrections , the theoretical framework elaborated in the present work makes assumptions about the regularization of endpoint divergences .
there are of course other possibilities
. nevertheless , we believe that our method is useful in pqcd analyses of the @xmath33 meson exclusive decays and heavy - to - light @xmath597 transition form factors in the domain of moderate momentum transfers . a generalization of the rc method to describe time - like transitions as well as its combination with resummation techniques to include sudakov logarithms will be the subject of separate investigations .
+ one of the authors ( s.s.a . ) would like to thank prof .
s. randjbar - daemi and the high energy section members for their hospitality at the abdus salam ictp , where this work was started and prof .
k. goeke and the members of the institute for theoretical physics ii , where this investigation was completed .
both of us wish to thank m. polyakov , a. bakulev , a. belitsky , and k. passek - kumeriki for useful comments . the financial support by daad ( s.s.a .
) is gratefully acknowledged . in the @xmath274 case the da s @xmath234 and @xmath602 of the @xmath1-meson
have the form ( [ eq:2.43 ] ) as well , the only difference being in the functions @xmath270 and @xmath271 , which now are defined by the expressions @xmath603 in the previous sections all results have been written down for @xmath265 valid for a momentum transfers @xmath605 . for momentum transfers in the range @xmath606 , the choice @xmath274 has to be employed . in this case , the expressions that determine the quark component of the transition ff remain unchanged , except for the function @xmath270 ( and @xmath607 , @xmath307 ) , which should be taken from eq .
( [ eq:1app ] ) .
the expressions for the gluon component of the ff have to be rescaled by a factor @xmath608 apart from the replacement of the function @xmath271 ( and @xmath607 , @xmath307)since the hard - scattering amplitudes @xmath609 explicitly depend on @xmath185 ( [ eq:2.34 ] ) .
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analytic expressions for the ff s @xmath3 and @xmath4 are also presented , as well as borel transforms @xmath5(u)$ ] and resummed expressions .
it is shown that except for @xmath6 , the borel transform contains an infinite number of infrared renormalon poles .
it is demonstrated that in the explored range of the total gluon virtuality @xmath7 , power corrections found with the rc method considerably enhance the ff @xmath8 relative to results obtained only in the context of the standard hsa with a `` frozen '' coupling . |
let @xmath201 be the eigenstates of a given qubit - qudit state @xmath79 with eigenvalues @xmath202 .
then @xmath203 is a purification of @xmath79 in a @xmath80 system @xmath81 .
then @xmath204 is of rank 2 and is supported on the 2-dimensional subspace spanned by an orthornormal basis @xmath205 any state @xmath206 supported on the subspace spanned by @xmath207 can be expanded @xmath208 with the help of four generalized pauli operators @xmath209 where coefficients @xmath210 ( @xmath211 ) are real @xmath23 .
for example we have @xmath212 . from the fact
@xmath213 it follows that @xmath214 and @xmath215\cr & = & 2\sum_{\mu,\nu=0}^3{{\rm tr}}[(1-v^b_{12})\sigma_\mu^a\otimes\sigma_\nu^a\tilde\varrho_{ab}\otimes\tilde\varrho_{ab}]r_\mu r_\nu\cr & = & \sum_{\mu,\nu=0}^3[q_{\tilde\varrho}]_{\mu\nu}r_\mu r_\nu,\ ] ] in which @xmath216 has been defined in eq.([q ] ) .
the proof of the theorem is divided into the following four steps .
_ lemma _ i ) @xmath82 , ii ) @xmath85 , iii ) @xmath217 , and iv ) for a two - qubit state @xmath79 the bound @xmath218 holds true .
the entanglement of formation , concurrence , and tangle of @xmath84 are defined to be , respectively , @xmath219 where the minimization is taken over all possible ensembles @xmath220 with @xmath221 being pure and @xmath222 .
_ proof . _
i ) let @xmath223 be the optimal ensemble for @xmath75 and we obtain @xmath224 in which the first inequality is due to @xmath67 the second and third inequalities are due to the fact that @xmath63 is a convex and increasing function of @xmath64 , respectively .
\ii ) since @xmath84 is of rank 2 , its concurrence @xmath225 can be exactly evaluated according to _ theorem 4 _ in @xcite , where @xmath226 is the second largest solution to the equation @xmath227 . since the local filter @xmath41{1-x^2}/\sqrt{2\varrho_a}$ ]
acting on qubit @xmath6 brings @xmath42 to @xmath43 and induces an lt to @xmath42 we have @xmath44 and consequently @xmath85 .
\iii ) for an arbitrary state @xmath208 , with @xmath228 and @xmath229 denoting the reduced density matrices , we introduce a @xmath230 matrix @xmath231 whose elements are given by @xmath232\cr & = & \frac14\sum_{\mu,\nu=0}^3{{\rm tr}}[(1-v^b_{12})(1-v^c_{12})\sigma^{bc}_\mu\otimes\sigma^{bc}_\nu]r_\mu r_\nu\cr & : = & \sum_{\mu,\nu=0}^3 m_{\mu\nu}r_\mu r_\nu,\ ] ] according to _ theorem 1 _ in @xcite we have @xmath233 where @xmath234 is the smallest eigenvalue of the @xmath46 matrix @xmath235 obtained by deleting the first row and column of the @xmath230 matrix @xmath231 defined above .
it turns out that @xmath236 where @xmath237 which proves lemma iii .
\iv ) let @xmath238 be an optimal decomposition of @xmath84 for the tangle @xmath87 and we have @xmath239 , the eigenvector of @xmath160 corresponding to its largest eigenvalue @xmath48 , and @xmath240 .
if @xmath50 is the unit vector along the direction @xmath51 then we have @xmath241 and @xmath242 .
therefore if we measure the observable @xmath243 on the qubit @xmath6 we obtain outcome @xmath244 with probability @xmath245 leaving qubit @xmath10 in the state @xmath246 .
thus @xmath247 in which the second equality is due to the fact that @xmath248 is a qubit state and the inequality is due to the fact that @xmath89 is a concave function of @xmath64 .
it follows immediately that @xmath249 _ proof of the theorem . _
the upper bound is trivially true . because of the kaishi - winter relation @xcite @xmath74 , lemmas i and ii lead to the lower bound in the first statement . in the case of two qubits ,
since @xmath250 leading to @xmath251 , the lower bound of @xmath12 in eq.([bds ] ) becomes @xmath252 .
from lemma iv we see that @xmath93 is an upper bound of @xmath253 and therefore also an upper bound of @xmath12 . if @xmath73 then @xmath254 because of lemma iii , which means that the upper and lower bound coincide . | quantum discord quantifies quantum correlations beyond entanglement and assumes nonzero values , which are notoriously hard to compute , for almost all quantum states .
here we provide computable tight bounds for the quantum discord for qubit - qudit states . in the case of two qubits
our lower and upper bounds coincide for a 7-parameter family of filtered @xmath0-states , whose quantum discords can therefore be evaluated analytically .
an application to the accessible information of the binary qubit channel is also presented . for the qubit - qudit state output by the circuit of deterministic computation with one qubit , nontrivial lower and upper bounds that respect the zero - discord conditions are obtained for its quantum discord .
the quantum discord @xcite has gradually become another important resource for quantum informational processing tasks besides the entanglement .
firstly , in certain quantum mechanical tasks such as the deterministic quantum computation with one qubit ( dqc1 ) @xcite , the quantum advantages can be gained @xcite with the presence of quantum discord while the entanglement is absent .
secondly the quantum discord is shown to be a better indicator of the quantum phase transition in certain physical systems than the entanglement @xcite .
thirdly , in addition to its original interpretation via maxwell demon @xcite , the operational interpretations of quantum discord via state merging @xcite establish firmly the status of the quantum discord as an essential resource amidst other concepts of quantum information . as a measure of the quantum correlation beyond entanglement , the quantum discord of a given state @xmath1 of a composite system @xmath2 is @xcite @xmath3 where @xmath4 denotes the von neumann entropy and the minimum is taken over all the positive operator valued measures ( povms ) @xmath5 on the subsystem @xmath6 with @xmath7 being the probability of the @xmath8-th outcome and @xmath9 being the conditional state of subsystem @xmath10 .
the minimum can also be taken over all the von neumann measurements @xcite .
these two definitions are in general inequivalent even for qubits and our proposed bounds in eq.([bds ] ) below apply to both of them .
when the measurements are made on subsystem @xmath10 the quantum discord @xmath11 can be defined similarly and is in general different from @xmath12 .
quantum discord assumes nonnegative values and zero - discord states are relatively well understood : @xmath13 if and only if there exists a complete orthonormal basis @xmath14 for the subsystem @xmath6 together with some density matrices @xmath15 for the subsystem @xmath10 such that @xmath16 .
recently various methods to detect zero discord @xcite have been proposed for a given state as well as for an unknown state @xcite . besides its initial motivation in pointer states in measurement problem @xcite , vanishing quantum discord
is also found to be related to the complete positivity of a map @xcite and the local broadcasting of quantum correlations @xcite .
unfortunately zero - discord states are of zero measure @xcite and the nonzero values of the quantum discord are notoriously difficult to compute because of the minimization over all the possible measurements .
there are only a few analytical results including the bell - diagonal states @xcite and rank-2 states @xcite , in addition to a thorough numerical calculation @xcite in the case of von neumann measurements . for two - qubit @xmath0-states ,
since there are counter examples @xcite for the algorithm proposed in @xcite , the evaluation of their quantum discords remains a nontrivial task .
it is therefore desirable to have some computable bounds for the quantum discord so that the question of how large or small the quantum discord can possibly be , e.g. , in the dqc1 circuit , can be answered more reasonably . in this letter
we shall provide computable tight bounds for the quantum discord of qubit - qudit states . for a family of two - qubit
filtered @xmath0-states with 7 parameters up to local unitary transformations ( luts ) our lower and upper bounds coincide so that their quantum discords can be evaluated analytically .
also we present an application to the accessible information of the binary qubit channel for which our lower and upper bounds can coincide . for the quantum discord of the qubit - qudit state output by the dqc1 circuit we derive nontrivial lower and upper bounds , which qualitatively agree with the zero discord conditions @xcite comparing with the estimation in @xcite . to present our main result
we need some notations .
first of all , we denote by @xmath1 a qubit - qudit state with the reduced density matrices @xmath17 and @xmath18 for the qubit @xmath6 and the qudit @xmath10 respectively .
let @xmath19 be the bloch vector for @xmath17 with its length given by @xmath20 .
without loss of generality we assume that the reduced density matrix @xmath17 of qubit @xmath6 , on which the measurement is performed , is invertible since otherwise we have a product state , which has zero discord .
therefore the following filtered density matrix is well defined : @xmath21 secondly , let @xmath22 @xmath23 be the identity matrix and three standard pauli matrices .
we associate with every qubit - qudit state @xmath1 ( or @xmath24 ) a positive semi - definite two - qubit operator @xmath25=\frac14\sum_{\mu,\nu=0}^3[q_\varrho]_{\mu\nu}\sigma_\mu\otimes\sigma_\nu\ ] ] in which @xmath26 stands for the two - qudit swapping operator . then the equation @xmath27 , where @xmath28 , has four real solutions @xmath29 @xcite .
it should be noted that each @xmath30 is as readily computable as the concurrence of @xmath1 , which equals to @xmath31 @xcite , in the case of two - qubit states for which we have @xmath32 with @xmath33 being the @xmath34 correlation matrix defined by @xmath35_{\mu\nu}=\langle\sigma_\mu\otimes\sigma_\nu\rangle_\varrho$ ] .
these values @xmath36 , showing explicitly the dependence on @xmath1 , are invariant under an arbitrary lorentz transformation ( lt ) @xmath37 , satisfying @xmath38 , that brings @xmath39 to @xmath40 .
the local filter @xmath41{1-x^2}/\sqrt{2\varrho_a}$ ] acting on qubit @xmath6 brings @xmath42 to @xmath43 and induces an lt to @xmath42 , from which it follows that @xmath44 .
thirdly , we denote by @xmath45 the @xmath46 matrix obtained from the @xmath34 matrix @xmath47 by deleting its first row and column
. let @xmath48 be the largest eigenvalue of @xmath45 corresponding to the eigenvector @xmath49 .
we define @xmath50 to be the unit vector along the direction @xmath51 , where @xmath52 and @xmath53 . in the case of @xmath54
we define @xmath55 . by measuring the observable @xmath56 on the qubit @xmath6
we obtain a suboptimal value @xmath57 for the quantum discord as in eq.([def ] ) without minimization . for a two - qubit state @xmath1 , since @xmath58 , we have @xmath59 where @xmath60 is the @xmath46 correlation matrix for @xmath24 defined by @xmath61_{ab}=\langle\sigma_a\otimes\sigma_b\rangle_{\tilde\varrho}$ ] @xmath62 .
lastly , we need to introduce an increasing convex function @xmath63 of @xmath64 where @xmath65 and @xmath66 . for any density matrix
@xmath1 it holds @xmath67 since we always have @xmath68 and if @xmath69 we have @xmath70 which can be read off from the information diagram between the entropy and index of coincidence @xcite .
_ theorem _ for a qubit - qudit state @xmath1 , with subsystem @xmath6 being a qubit , the following bounds hold @xmath71 where @xmath72 . in the case of two qubits , the lower and upper bounds
coincide if @xmath73 .
a detailed proof can be found in @xcite and an outline is given in what follows .
the upper bound holds true by definition .
the key to prove the lower bound is the koashi - winter relation @xcite : @xmath74 , where @xmath75 is the entanglement of formation @xcite of the @xmath76 state @xmath77 with @xmath78 being a purification of @xmath79 in a @xmath80 system @xmath81 .
the lower bound follows from @xmath82 , where @xmath83 is the concurrence of @xmath84 , and an evaluation of the concurrence @xmath85 by applying _
theorem 4 _ in @xcite .
furthermore the ensemble of @xmath84 induced by measuring @xmath86 on qubit @xmath6 is optimal for the tangle @xmath87 of @xmath84 whose value @xmath88 can be readily obtained by applying _
theorem 1 _ in @xcite .
since @xmath89 is a concave function of @xmath64 we have bound @xmath90 , which coincides with the lower bound if @xmath73 , i.e. , @xmath91 , since @xmath92 in the case of two qubits .
randomly chosen 2-qubit states of rank 4 . ] for two - qubit states we have carried out some numerical calculations and a comparison with our bounds is shown in fig.1 , where for convenience the upper bound is taken to be @xmath93 , which is slightly weaker than eq.([bds ] ) . for about 70% of @xmath94 randomly chosen states of rank 4 the differences between our bounds and the values of quantum discord obtained by minimization over von neumann measurements lie in the range of @xmath95 with a maximal difference about @xmath96 .
we note that for some states our lower bounds are negative and therefore are trivial . on the other hand there exist several nontrivial families of states , for which the upper and lower bounds coincide so that analytical expressions of quantum discord for these states can be obtained . in these cases
the two definitions of quantum discord become identical .
_ example 1 : bell - diagonal states @xcite . _
a bell - diagonal state has a density matrix @xmath97 with @xmath98 being real and @xmath99 .
it is clear that @xmath100 and @xmath101 . as a result
we have @xmath102 so that upper and lower bounds as in eq.([bds ] ) coincide .
_ example 2 : rank-2 states @xcite .
_ every two - qubit state of rank 2 admits a 3-qubit purification @xmath78 with the reduced density matrix @xmath84 being a two - qubit state of rank 2 . as a result @xmath103 so that the upper and lower bounds as in eq.([bds ] ) coincide
.
_ example 3 : @xmath0-states .
_ in many scenarios @xmath0-state arises as the two - particle reduced density matrix as long as there is a certain symmetry of the physical system . in general
a 2-qubit @xmath0-state @xmath104 has 7 independent real parameters .
since the quantum discord is invariant under luts , we can assume without loss of generality that @xmath105 and @xmath106 are real and therefore we have in fact only 5 real parameters , which can be conveniently taken as those nonzero entries of the correlation matrix @xmath107 , i.e. , @xmath108 , @xmath109 , and @xmath110 ( @xmath111 ) .
since @xmath112 holds for qubits it is easy to see that four solutions to the equation @xmath113 are @xmath114 and @xmath115 .
furthermore the @xmath116 correlation matrix @xmath117 is diagonal with entries @xmath118 and @xmath119 .
thus as long as @xmath120 so that the upper and lower bounds of the quantum discord coincide .
we denote by @xmath121 the @xmath0-state that satisfies the condition eq.([cond ] ) and the optimal observable to measure is @xmath122 if @xmath123 and @xmath124 otherwise .
explicitly , @xmath125 _ example 4 : filtered @xmath0-states . _
take an arbitrary 2-qubit state @xmath1 satisfying i ) @xmath73 , i.e. , the upper and lower bounds for @xmath12 coincide , and ii ) @xmath17 is proportional to identity , for example the state @xmath121 with @xmath54 as in example 3 , and take an arbitrary invertible hermitian operator @xmath126 acting only on qubit @xmath6 .
then for the filtered state @xmath127 we have @xmath128 from the definition eq.([tilde ] ) so that @xmath129 has also a coincided lower and upper bound . because @xmath130 and @xmath126 represent the same filter for any nonzero real @xmath131 , there are @xmath132 independent real parameters for @xmath126 .
thus we have a family of filtered @xmath0-states with 7 parameters for which the quantum discords can be evaluated analytically .
_ example 5 : accessible information . _
a quantum communication channel @xmath133 is defined by the action of sending states @xmath134 with probabilities @xmath135 to a receiver who can perform any possible povm to gain the information of @xmath135 .
the accessible information @xmath136 is the maximum of the mutual information of the joint probability distribution @xmath137 over all povms @xmath138 .
if we introduce a bipartite state @xmath139 where @xmath14 is a complete orthonormal basis then we have @xmath140 and @xmath141 where @xmath142 is the holevo bound . for qubit channels the theorem provides an upper bound @xmath143 as well as a lower bound given by the measurement along @xmath144 for the accessible information .
consider a binary qubit channel @xmath145 and denote by @xmath146 and @xmath147 the bloch vectors of qubit states @xmath148 and @xmath149 , respectively , and @xmath150 .
the lower bound for @xmath136 provided by @xmath144 coincides with the lower bound ( @xmath151 ) in @xcite .
the @xmath34 correlation matrix of the two - qubit state @xmath152 reads @xmath153 where @xmath154 .
we note that @xmath155 is of rank 2 and therefore four solutions to the equation @xmath156 are @xmath157 , where @xmath158 from which we obtain @xmath159 .
the @xmath116 correlation matrix @xmath60 of @xmath24 is of rank 1 and the largest eigenvalue of @xmath160 is @xmath161 . by solving @xmath73
we obtain @xmath162 in which case the upper and lower bounds for @xmath136 coincide , meaning that the optimal povm for @xmath136 is a von neumann measurement ( along the direction @xmath163 ) .
this proves explicitly , for the first time as far as we know , that the optimal von neumann measurement given in @xcite is also optimal among povms .
_ example 6 : dqc1 states .
_ let us consider the qubit - qudit state output by the dqc1 circuit , aiming at calculating efficiently the trace of a unitary operation @xmath164 acting on the qudit @xmath10 , with a density matrix @xcite @xmath165 where @xmath166 and @xmath167 .
let @xmath168 be the eigensystem of @xmath164 and obviously @xmath169 is separable where @xmath170 with @xmath171 .
the nonvanishing quantum discord of @xmath172 , which has been estimated in @xcite , is argued to be responsible for the quantum speedup .
recently it is found that @xcite @xmath173 if and only if @xmath174 or @xmath175 where @xmath176 . the estimation in @xcite ,
though respects the trivial condition @xmath174 , is insensitive to the condition @xmath175 , i.e. , a nonzero value of the quantum discord is estimated in this case , in which @xmath177 and @xmath164 can be in the same time typical , i.e. , @xmath178 .
our theorem provides nontrivial bounds that respect both two zero - discord conditions .
for simplicity we shall assume @xmath179 first , i.e. , @xmath180 .
in this case we have @xmath181 and @xmath182 .
it turns out that @xmath183 where @xmath184 has eigenvalues @xmath185 . as a result
we have @xmath186 ( @xmath187 ) which is also the largest eigenvalue of @xmath188 with eigenvector @xmath189 where @xmath190 . from eq.([bds ] ) and @xmath191 for @xmath192 it follows @xmath193 in deriving the upper bound we have used @xmath194 in which the first inequality is valid for arbitrary @xmath195 and becomes an equality in the case of @xmath179 .
thus the upper bound for @xmath196 given in eq.([b3 ] ) holds for all unitary @xmath164 and reaches its maximum @xmath197 at @xmath198 and @xmath199 .
it is obvious that in the case of @xmath174 or in the case of pure qubit @xmath198 and @xmath175 the lower and upper bounds coincide so that the quantum discord vanishes . to conclude , in view of the hardship of computing the nonzero values of quantum discord
, the computable tight bounds provided here for qubit - qudit states should be useful in further quantitative studies of the relation between quantum discord and phase transitions , quantum speedups , and so on .
notably our bounds enable us to evaluate analytically the quantum discords of a family of filtered @xmath0-states with 7 parameters up to luts ( for comparison there are 9 parameters for a general 2-qubit state ) and to estimate the quantum discord in the dqc1 circuit more reasonably .
also our bounds are applicable for the classical correlation and accessible information .
though we have restricted to qubit - qudit systems , for which the concurrence @xmath83 can be evaluated exactly , the bounds for the quantum discord @xmath200 of a general bipartite state , which might not be specially tight , can be obtained in a similar way via the bounds for the entanglement of formation @xmath75 .
we acknowledge the financial supports of a*star grant no . r-144 - 000 - 189 - 305 , cqt project wbs : r-710 - 000 - 008 - 271 , and nnsf of china ( grant no .
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SECTION 1. SHORT TITLE.
This Act may be cited as the ``Enterprise Zone Environmental
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carry out the purposes of this Act. | Enterprise Zone Environmental Restoration Act of 1993 - Directs the Administrator of the Environmental Protection Agency to establish a program to award grants for environmental testing and characterization on land owned by political subdivisions of States to political subdivisions that submit approved applications for such activities on impacted sites. Defines an "impacted site" as an area designated as an enterprise zone pursuant to the Housing and Community Development Act of 1987 or that receives a similar designation under other Federal law.
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Sets forth conditions for the receipt of grants.
Authorizes appropriations. |
interacting particles in confinement potentials are omnipresent in nature and laboratory systems such as trapped ions , e.g. @xcite , dusty plasmas , e.g. @xcite or ultracold bose and fermi gases @xcite .
an interesting aspect of particle traps is that it is easy to realize situations of strong correlations .
the observed particle arrangements reach from gas - like , liquid - like to solid behavior where the symmetry is influenced by the trap geometry .
of particular recent interest have been spherical traps in which plasma crystals consisting of spherical shells ( yukawa balls ) are formed , e.g. @xcite .
the particle distribution among the shells is by now well understood @xcite . in a recent study @xcite
we have analyzed also the average particle density in the trap and found that it is very sensitive to the binary interaction : it changes from a flat profile in case of long - range coulomb interaction to a profile rapidly decaying away from the trap center in the case of a screened yukawa potential . using a non - local mean - field ( mf ) approximation the density profile could be computed analytically and was found to agree very well with first principle computer simulations for yukawa crystals .
however , when the screening is increased deviations in the trap center kept growing which were attributed to correlation effects missing in the mean - field model .
the goal of this paper is to remove these discrepancies . for this
we extend the analysis of ref .
@xcite by including correlation effects following an idea of totsuji et al .
@xcite applied to 2d systems .
we apply the local density approximation ( lda ) using known results @xcite for the correlation energy of a homogeneous one - component yukawa plasma .
the results clearly confirm that correlation effects are responsible for the strong density increase in the trap center .
we find that lda with correlations included agrees very well with simulations of yukawa crystals in the limit of strong screening . on the other hand , for weak screening ,
the previous mf result turns out to be more accurate .
interestingly , for intermediate values of the screening parameter both methods are accurate , so a combination of both allows to quantitatively describe the density profile in the whole range of screening parameters .
this paper is organized as follows . in sec .
ii we introduce the lda and use it first to compute the density profile in a mean - field approximation , which , of course , gives worse results than mf , but helps to understand lda . then , in sec .
iii we improve the lda model by including correlation effects . in sec .
iv the results for the density profile are compared to molecular dynamics simulations .
a discussion is given in sec .
we consider @xmath0 identical particles with mass @xmath1 and charge @xmath2 confined by an external potential @xmath3 and interacting with the isotropic yukawa - type pair potential , @xmath4 . to derive the properties of interest we start with the expression of the ground - state energy , which is given by @xmath5=\int d^3r\ , u({\bf r}),\ ] ] with the energy density @xmath6 , where the mean - field energy density is @xmath7 the correlation contribution @xmath8 will be discussed below ( sec .
iii ) by means of the local density approximation . before , we introduce this approximation and obtain first the lda results in mean - field approximation ( lda - mf )
. these results will not be as accurate as the mf results , due to the applied approximation , but lda - mf helps to familiarize oneself with lda and its characteristics .
the local density approximation is based upon the idea of replacing the non - local terms within the energy density at point @xmath9 by local expressions using the known energy density of the homogeneous system with its density @xmath10 equal to the local density @xmath11 of the true inhomogeneous system in question .
therefore , to derive lda - mf we need to substitute for the non - local second term in , i.e. for the density of interaction energy , the corresponding expression of the infinite homogeneous system , which is given by [ details are given in the appendix ] @xmath12 and , as a second step , replace the homogeneous density @xmath10 by the local density @xmath11 .
thus we obtain the lda - mf ground - state energy @xmath13=\int d^3r\ , u({\bf r})\ ] ] with the energy density @xmath14 the variation of the energy @xmath15=e^\text{mf}_\text{lda}[n]+\mu\biggl\{n-\int d^3r\ , n({\bf r})\biggr\}\ ] ] with respect to the density @xmath11 ( for details see ref .
@xcite ) yields an explicit expression for the density profile in an arbitrary confinement potential @xmath16 which holds at any point where the density is nonzero . due to
this density is normalized by @xmath17 the case of an isotropic confinement @xmath18 , which is of particular interest , leads to an isotropic density distribution @xmath19 the outer radius @xmath20 of which is being fixed by the normalization condition which now becomes @xmath21 . in this isotropic case
the yet unknown lagrange multiplier @xmath22 can be obtained by taking the variation also with respect to @xmath20 @xcite , which yields @xmath23 compared to the mf result which was given in @xcite , @xmath24 the lda - mf density differs in two points . on the one hand the laplacian of the potential @xmath25 is missing and , on the other hand , the expression of the chemical potential @xmath22 is simpler than @xmath26 .
that is based upon the fact , that the missing expressions consist of derivatives and thus contain informations about contiguous values of the potential , what is suppressed within lda - mf and generally within lda . and
a constant screening parameter @xmath27 and three different particle numbers @xmath28 .
also the result for @xmath29 , @xmath30 is shown by the dashed line .
for comparison , the non - local mf results for @xmath31 , @xmath30 are given by the dotted lines.,width=323,height=226 ] for the case of a parabolic external potential @xmath32 the density following from eqs . and
is @xmath33 the dimensionless combination @xmath34 , which contains the limiting outer radius , can be obtained from the normalization and is given by @xmath35{\frac{15 ( n-1 ) q^2 \kappa^3}{\alpha}}\\ & = \sqrt[5]{\frac{15}{2}(\kappa d_c)^3(n-1)}. \end{split}\ ] ] here , we introduced the length scale @xmath36 , which is the stable distance of two charged particles in the absence of screening @xcite and which will be used below as the proper unit for lengths and screening parameters .
as unit for densities we use the average density of a large coulomb system , which is given by @xmath37 .
the results of are shown in fig .
[ fig : ldaresults ] for three particle numbers from @xmath38 to @xmath30 .
one clearly sees the parabolic decrease of the density away from the trap center till it terminates in zero .
the curvature of the density does not change by increasing the particle number - just the density increases continuously at every space point and , at the same time , extends to higher values of the limiting radius @xmath20 .
however , the curvature of the density profile changes dramatically , when the plasma screening is increased at constant @xmath0 . thus , in the case of an isotropic parabolic potential , the lda density profile bears qualitative resemblance to the density profile in the non - local mean - field approximation , although in the case of other confinement potentials the deviations of the lda - mf from the mf approximation are stronger , cf .
eqs . and .
however , quantitatively in two points mf differs from lda - mf for parabolic confinement as well , as can also be seen in fig .
[ fig : ldaresults ] . .
the abscissa is normalized with the mf radius @xmath39 , while the ordinate is normalized with the corresponding mf density @xmath40 at the trap center.,width=323,height=226 ] first , the density in this local density approximation does not show a discontinuity at @xmath41 , in contrast to the mf result , eqs .
( [ eq : general_meanfielddensity ] , [ eq : general_meanfieldmu ] ) .
this is due to the neglect of edge effects in this derivation of the lda result .
secondly , lda - mf yields too small values of the density .
this error is reduced ( cf .
[ fig : ldacomparison ] ) with increasing values of the density parameter @xmath42 , cf .
@xcite , which regardless of the factor @xmath43 solely determines the density profile .
the reason for this improved behavior with increasing @xmath44 is due to the fact that an increase of @xmath45 contracts the effective area of integration within as well as within .
the contraction finally is in favor of the accuracy of lda - mf , because the decreased integration volume contains a more homogeneous density .
also an increase of the particle number @xmath0 , what flattens the density profile , will similarly improve lda - mf . because the validity of the mean - field model depends on the value of the screening parameter @xmath46
, there are the following two cases . in the first case , for small values of the screening parameter
, the mf approximation provides a good description of the density profile , but lda - mf underrates this profile and so does not give a good description on its own .
( that applies also if finite - size effects are included , cf .
[ fig : lda - finitesize ] . ) in the second case , for large values of the screening parameter , the lda - mf approaches the mf approximation , however , there , the latter does not describe the density profile correctly due to the neglect of the now relevant correlation contributions @xcite .
thus , the local density approximation of the mean - field energy alone does not give a good description of the density profile .
however , it gives a straightforward way to include the missing correlation contributions in the energy density by usage of the result of the homogeneous system , see sec .
[ section_correlation ] . as can be seen from fig .
[ fig : ldacomparison ] and from eq . the density profile obtained by lda - mf breaks down in the coulomb case
- the density can not be normalized anymore , which is the same as in the two - dimensional case @xcite .
but the application of a local density approximation can not be the reason for this , because the method of lda is based upon the usage of results from the homogeneous system , and the coulomb system is homogeneous with @xmath47 n_c$ ] . and
@xmath48 calculated by lda - mf with ( fs corrected ) and without finite - size effects included . for comparison
the exact mf result is also given by the dashed line .
the difference between the finite - size correction and the partial finite - size correction is described in the text.,width=323,height=226 ] in fact , the cause of the breakdown is the use of results from the infinite homogeneous system neglecting finite - size effects .
this failure can be avoided by replacing by the corresponding expression of the finite homogeneous system . in the appendix such an expression
is derived for isotropic confinement . as a result
the finite - size effects lead to a corrected density profile @xmath49 instead of eq .
, what indeed yields the constant mf solution also for lda - mf . as another example , in fig .
[ fig : lda - finitesize ] the density profiles with [ lda - mf ( fs corrected ) ] and without these finite - size contributions are shown for @xmath50 , @xmath48 .
one clearly sees , that in the case of finite - size correction the density profile shows a discontinuity at the boundary and , due to that , it yields increased values of the density .
however , the density profile including edge effects is not monotonically decreasing away from the trap center but has a density increasing part in the outer range , what is not correct .
this is due to the spatial dependence of the denominator of eq . .
by contrast a more accurate monotonically decreasing density profile can also be obtained by taking the finite - size effects only partly into account [ lda - mf ( partly fs corrected ) ] , as derived in the appendix .
the final result is given by @xmath51 which now misses the spatial dependence in the denominator .
the corresponding result is also given in fig .
[ fig : lda - finitesize ] .
consequently , for yukawa systems like those analyzed here an improvement of lda is possible by including edge effects .
however , for small values of the screening parameter even the improved local density approximation does not approach the degree of accuracy obtained by the non - local mean - field model , cf .
[ fig : lda - finitesize ] . on the other hand , for increased screening the finite - size effects
do not alter the density profile significantly .
therefore , below we continue to use eq . of the infinite homogeneous system , what will not interfere the following results .
the energy expression @xmath52 ( [ eq : energy_lda],[eq : energydensity_lda ] ) contains only the energy density of the confinement and of the mean - field interaction . to include the contribution of the particle correlations we can make use of the result for the density of correlation energy of the homogeneous system which is given by eq .
( 3 ) of ref . @xcite @xmath53 where @xmath10 is the corresponding density of the homogeneous system . by replacing this density with the local density @xmath11 of the inhomogeneous system one obtains the correlation contribution of the energy density within lda .
thus we derive the complete ground - state energy in local density approximation @xmath54=\int d^3r\ , u({\bf r})\ ] ] with energy density @xmath55 as before , variation of the energy at constant particle number , cf .
eq . , yields the ground state density profile , but now with correlation effects included . in this case
the strong non - linear character of the energy density does not allow for an explicit solution .
just an implicit solution is possible and is given by the following equation for @xmath56 , which can be regarded as the local plasma parameter of the system , @xmath57 the constants @xmath58 are given by @xmath59 the solution of eq .
can be obtained numerically . for the case of a parabolic external potential @xmath32 results
are given in fig .
[ fig : ldacorrresults ] .
there , the density profile of a plasma of @xmath30 particles within lda is shown for three different screening parameters : @xmath60 , @xmath61 and @xmath62 .
for comparison the lda - mf density profile is shown too .
particles calculated with lda including correlation contributions ( solid lines ) compared to lda - mf ( dashed lines ) for three different screening parameters.,width=323,height=226 ] it can be seen that for a small screening parameter ( see line @xmath60 ) both density profiles are nearly identical . but with increasing screening , i.e. for smaller values of the local plasma parameter @xmath63 , the correlation contributions within lda alter the curvature of the profile , which rises more steeply towards the center .
so the particle correlations tend to increase the central density of the plasma , which also can be seen in fig .
[ fig : ldacorrcomparison ] in comparison with the mean - field approximation .
particles calculated with the exact mean - field model ( solid lines ) and with lda including correlation contributions ( dashed lines ) for four different screening parameters : @xmath27 , @xmath64 , @xmath65 and @xmath66 . averaged shell densities of molecular dynamics results of a plasma crystal for the same parameters
are shown by the symbols .
for details see discussion in sec .
[ sec : comparison_with_simulation_results ] .
, title="fig:",width=323,height=226 ] particles calculated with the exact mean - field model ( solid lines ) and with lda including correlation contributions ( dashed lines ) for four different screening parameters : @xmath27 , @xmath64 , @xmath65 and @xmath66 .
averaged shell densities of molecular dynamics results of a plasma crystal for the same parameters are shown by the symbols .
for details see discussion in sec .
[ sec : comparison_with_simulation_results ] .
, title="fig:",width=323,height=226 ] and two different screening parameters ( @xmath27 , @xmath65 ) .
the solid ( dashed ) lines show mf ( lda ) calculation results .
symbols denote molecular dynamics results of a plasma crystal for the same parameters where the average density at the positions of the shells is shown.,width=323,height=226 ]
we performed molecular dynamics simulations of the ground state of a large number of coulomb balls for the purpose of comparison with the average density of spherical yukawa crystals , see refs .
@xcite for details .
in order to obtain a smooth average radial density profile the averaging process was accomplished by substituting each particle by a small but finite sphere .
numerical results of this comparison with a coulomb ball of @xmath50 particles are included in fig .
[ fig : ldacorrcomparison ] for four different screening parameters .
the symbols denote the average particle density in the vicinity of the corresponding shell , while the lines represent the mf ( solid ) and the lda density ( dashed ) . for small values of the screening parameter @xmath67 the simulation results are very well reproduced by the analytical density profile of the non - local mean - field model ( mf ) , whereas the local density approximation underrates the results ( lower lines in fig .
[ fig : ldacorrcomparison ] ( a ) ) . on the other hand
, for larger values of the screening parameter @xmath68 the simulation results are reproduced by lda , whereas mf underestimates these results in the center .
this underestimation is accompanied by a wrong prediction of the profile curvature ( fig .
[ fig : ldacorrcomparison ] ( b ) ) . for intermediate values of the screening parameter @xmath69
both methods are very close to the averaged simulation results ( upper lines in fig .
[ fig : ldacorrcomparison ] ( a ) ) .
we have verified this behavior also for other coulomb balls .
another representative example is shown in fig .
[ fig : ldacorrcomparison2 ] for a coulomb ball with @xmath70 .
there , the same behavior as in fig .
[ fig : ldacorrcomparison ] is seen .
a theoretical analysis of the ground state density profile of a spatially confined one - component plasma within local density approximation was presented .
we derived a closed equation , eq .
, for the density profile including correlations effects for arbitrary confinement potentials with any symmetry .
in contrast to the result without particle correlations the density profile shows an increased central density with increasing screening parameter .
the validity of lda is however limited to not too small values of the screening parameter , @xmath71 .
comparisons with first - principle simulation results of strongly correlated coulomb clusters with varying screening parameter showed that lda allows to remove the problem of the mf approximation observed in ref .
@xcite which arises with increasing screening parameter .
therefore , the mean - field model together with the presented local density approximation complement one another in the description of strongly correlated spatially confined one - component plasmas .
the authors are indebted to d. block and a. melzer for fruitful discussions .
this work is supported by the deutsche forschungsgemeinschaft via sfb - tr 24 projects a3 , a5 and a7 .
the investigation of an inhomogeneous system within lda uses known results from the corresponding homogeneous system .
there , the infinite homogeneous system is often used as reference system what entails that finite - size effects are neglected . to take these into account
the finite homogeneous system has to be used as reference . in the present derivation
such a modification is made for an isotropic confinement and leads to a change of the expression for the density of interaction energy , eq .
, @xmath72 this formula has no spatial dependence due to the infinite integration volume and it diverges in the limit of coulomb interaction ( @xmath73 ) leading to a breakdown of the approximation .
by contrast , the density of interaction energy of the corresponding finite homogeneous system ( a sphere with center @xmath74 and radius @xmath20 ) is given by @xmath75 including a finite - size contribution , which prevents the problem of divergence at @xmath73 .
as already mentioned in sec .
[ section_fs_correction ] the resulting density profiles show the incorrect behavior of a non - monotonic density profile , cf .
[ fig : lda - finitesize ] .
an improved correction which only partly takes edge effects into account can yet be obtained by removing the explicit spatial dependence within the density of interaction energy @xmath76 this expression also has no divergent limit for @xmath73 , and , at the same time , yields monotonically decreasing density profiles as can also be seen in fig . [
fig : lda - finitesize ] . 26 d.j .
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a * 39 * , 4565 ( 2006 ) | the ground state of an externally confined one - component yukawa plasma is derived analytically using the local density approximation ( lda ) . in particular ,
the radial density profile is computed .
the results are compared with the recently obtained mean - field ( mf ) density profile @xcite . while the mf results are more accurate for weak screening , lda with correlations included yields the proper description for large screening . by comparison with first - principle simulations for three - dimensional spherical yukawa crystals we demonstrate that both approximations complement each other .
together they accurately describe the density profile in the full range of screening parameters . |
Piece of the real Santa in Morton Grove? Could be St. Nick, tests show
This pelvis fragment obtained by the Rev. Dennis O'Neill of Shrine of All Saints in Morton Grove could be a relic of St. Nicholas, Oxford University researchers found. | Tom Higham and Georges Kazan / Oxford University
Santa Claus is coming to town? It turns out that his ancient inspiration — St. Nicholas — might already be here, in Morton Grove, based on new findings from researchers at Oxford University.
The north suburb’s Shrine of All Saints includes thousands of saintly “relics” — bits of bone and locks of hair, as well as objects once owned or used by religious figures, such as clothing — on display for the curious and the faithful.
Several bone fragments said to have come from Jolly Old St. Nick himself are among the relics, which were collected over decades by the Rev. Dennis O’Neill, rector of the shrine and pastor of its home church, St. Martha Parish.
Oxford researchers visited the shrine last year. With O’Neill’s permission, they took tiny samples from items including a chunk of pelvis thought to possibly be from St. Nicholas — a Greek bishop from the third and fourth centuries in an area known as Myra, now part of Turkey — to test, hoping to determine whether they might be genuine.
Now — the week of the St. Nicholas feast day — the researchers in England have released their findings that radiocarbon dating of the piece of pelvis suggests O’Neill could indeed have a little bit of St. Nick.
“The radiocarbon dating results pinpoint the relic’s age to the fourth century AD — the time that some historians allege that St. Nicholas died,” around 343 AD, according to the researchers. “The results suggest that the bones could, in principle, be authentic and belong to the saint.”
Tom Higham, an Oxford researcher, said in a written statement: “Many relics that we study turn out to date to a period somewhat later than the historic attestation would suggest. This bone fragment, in contrast, suggests that we could possibly be looking at remains from St. Nicholas himself.”
O’Neill, who’s been collecting religious relics since he was a teenager on the South Side, said, “It’s very likely him . . . Pretty exciting.”
As is the story of how St. Nick’s bones ended up dispersed in the first place. In the centuries after he died, his “tomb in Myra became a popular place of pilgrimage,” according to the St. Nicholas Center in Holland, Mich. “Because of the many wars and attacks in the region, some Christians were concerned that access to the tomb might become difficult.
“For both the religious and commercial advantages of a major pilgrimage site, the Italian cities of Venice and Bari vied to get the Nicholas relics. In the spring of 1087, sailors from Bari succeeded in spiriting away the bones, bringing them to Bari, a seaport on the southeast coast of Italy.
“An impressive church was built over St. Nicholas’ crypt, and many faithful journeyed to honor the saint who had rescued children, prisoners, sailors, famine victims, and many others through his compassion, generosity and the countless miracles attributed to his intercession.”
Venetians ended up with some pieces of bone left at the original gravesite. And some relics eventually made their way to France, where they were hidden during the French Revolution as religious sites were pillaged and destroyed, according to O’Neill, who wrote a book on the items he’s collected.
O’Neill said his St. Nicholas bones came from France. He said he bought them a decade or so ago from a collector who said “they came from a convent in southern France.”
It can be a “sin” to sell relics, according to O’Neill, but it “can be a virtue to rescue them.”
Which he does with his own money. Some also have been given to him.
The Oxford tests are the first on bones believed to be from St. Nicholas, according to the university.
“Interestingly, the Bari collection does not include the saint’s full pelvis, only the left ilium (from the upper part of the bone),” according to Oxford.
Since O’Neill’s St. Nicholas “relic is from the left pubis (the lower part of the bone), this suggests that both bone fragments could be from the same person.”
Georges Kazan, another Oxford researcher, said in an interview the hope now is to test the Bari and Venice bones, match them against the one from Morton Grove and see whether they all came from the same person.
Kazan said it’s exciting to think such relics could be “genuine.”
According to Oxford, “The relics held in Venice consist of as many as 500 bone fragments, which an anatomical study concluded were complementary to the Bari collection, suggesting that both sets of relics could originate from the same individual. It remains to be confirmed what fragments of the pelvis are contained amongst the Venice relics, if any.”
There are items associated with nearly 1,800 Christian saints at the Morton Grove shrine, including bones said to have belonged to Jesus’ apostle St. Peter, which the Oxford team wants to test at some point.
Relics, though, have a controversial history. Kazan has written: “Many Christians saw relics as earthly repositories of God’s Holy Spirit, able to work miracles and bestow healing. They became invaluable commodities and symbols of status, particularly during the Middle Ages. After the Reformation, the trade in relics was seen as the embodiment of the worst excesses of superstition and cynicism.”
O’Neill said relics still hold purpose, including helping people better understand and model holy people of the past, and providing a different way of connecting to God.
In some ways, “They’re making a comeback,” O’Neill said. “There’s growing interest in them.”
O’Neill knows that some of his relics might not be authentic, either misidentified over the years or forged. But if they bring people closer to God, he said, they still have worth.
Over the years, relics have played a role in Eastern Orthodox, Catholic and even some Protestant traditions, as well as non-Christian faiths.
St. Nicholas was known for his generosity and care of children, though he didn’t fully “evolve” into Santa Claus until more than 1,000 years after his death.
Among the stories told about him, according to the St. Nicholas Center, there was a “poor man with three daughters” but no dowry — money to give to suitors. With little chance they’d be married, they were “destined to be sold into slavery.“Mysteriously, on three different occasions, a bag of gold appeared in their home providing the needed dowries. The bags of gold, tossed through an open window” by St. Nicholas, “are said to have landed in stockings or shoes left before the fire to dry.”
That was “the beginning of the link between him and Santa Claus,” O’Neill said.
Among the more contemporary relics at O’Neill’s shrine: a piece of clothing that once belonged to Edith Stein, a nun killed in the Holocaust, and strands of hair from Mother Teresa, the nun who tended to the poor in India and was recognized in 2016 as a saint. ||||| Image copyright T. Higham & G. Kazan Image caption The bone claimed to be from St Nicholas has been radio carbon tested for the first time
A fragment of bone claimed to be from St Nicholas - the 4th-Century saintly inspiration for Father Christmas - has been radio carbon tested by the University of Oxford.
The test has found that the relic does date from the time of St Nicholas, who is believed to have died about 343AD.
While not providing proof that this is from the saint, it has been confirmed as authentically from that era.
The Oxford team says these are the first tests carried out on the bones.
Relics of St Nicholas, who died in modern-day Turkey, have been kept in the crypt of a church in Bari in Italy since the 11th Century.
Authentic age
But the popularity of the saint, and the associations with Christmas, have seen many fragments of bones being taken to other locations, raising questions about how many of these are authentic.
The tests in Oxford have been carried out on a fragment of pelvis, which had been in a church in France and is currently owned by a priest, Father Dennis O'Neill, from Illinois in the United States.
Image copyright EPA Image caption St Nicholas figures meeting in southern Germany this week, at the start of the Christmas season
The radio carbon dating tests, for the Oxford Relics Cluster at Keble College's Advanced Studies Centre, have confirmed that the bone is from the correct era for St Nicholas.
Prof Tom Higham, a director of the centre, says this is unlike many such relics which often turn out to be much later inventions.
"This bone fragment, in contrast, suggests that we could possibly be looking at remains from St Nicholas himself," says the Oxford archaeologist.
There are hundreds of other bones claimed to be from St Nicholas, including a collection in a church in Venice.
And the researchers now want to use DNA testing to see how many bones are really from a single individual - and how many might be linked to the bone tested in Oxford.
The Oxford team are interested in whether the part of the pelvis they have tested matches the relics in Bari, where the collection does not include a full pelvis.
Dr Georges Kazan, co-director of the centre at Keble College, says: "It is exciting to think that these relics, which date from such an ancient time, could in fact be genuine."
For the researchers, this might seem like Christmas has come early. But the findings cannot provide evidence that this is definitely from the real St Nicholas.
"Science is not able to definitely prove that it is, it can only prove that it is not, however," says Prof Higham. ||||| Relic of St Nicholas (pelvis fragment) at St. Martha of Bethany Church/Shrine of All Saints, Morton Grove Ill., USA. Credit: copyright T. Higham & G. Kazan Was St Nicholas, the fourth century saint who inspired the iconography of Santa Claus, a legend or was he a real person?
New Oxford University research has revealed that bones long venerated as relics of the saint, do in fact date from the right historical period.
One of the most revered Orthodox Christian saints, the remains of St Nicholas have been held in the Basilica di San Nicola, Bari, Southern Puglia, since 1087, where they are buried in a crypt beneath a marble alter. Over the years relic fragments have been acquired by various churches around the world, calling into question how the bones can all be from the same person.
Using a micro-sample of bone fragment, Professor Tom Higham and Dr Georges Kazan, the Directors of the Oxford Relics Cluster at Keble College's Advanced Studies Centre, have for the first time tested one of these bones. The radio carbon dating results pinpoint the relic's age to the fourth century AD - the time that some historians allege that St Nicholas died (around 343 AD). The results suggest that the bones could in principle be authentic and belong to the saint.
Professor Higham said: "Many relics that we study turn out to date to a period somewhat later than the historic attestation would suggest. This bone fragment, in contrast, suggests that we could possibly be looking at remains from St Nicholas himself." St Nicholas is thought to have lived in Myra, Asia Minor, which is now modern day Turkey. According to legend he was a wealthy man who was widely known for his generosity, a trait that inspired the legend of Father Christmas as a bringer of gifts on Christmas Day.
Believed to have been persecuted by the Emperor Diocletian, the saint died in Myra, where his remains became a focus of Christian devotion. His remains are said to have been taken away by a group of Italian merchants and transported to Bari, where the bulk of them sit to this day in the Basilica di San Nicola.
The bone analysed is owned by Father Dennis O"Neill, of St. Martha of Bethany Church, Shrine of All Saints in Morton Grove Illinois, USA.
The relic originally came from Lyon in France but most of the bones believed to be from St Nicholas are still preserved in Bari, with some in the Chiesa di San Nicolo al Lido in Venice. Fr.O"Neill has acquired his collection over many years, mainly from churches and private owners in Europe, and includes a relatively large bone fragment which has been identified as part of a human pelvis, believed to be a relic of St Nicholas.
Interestingly, the Bari collection does not include the saint's full pelvis, only the left ilium (from the upper part of the bone). While Fr.O"Neil's relic is from the left pubis (the lower part of the bone) and suggests that both bone fragments could be from the same person.
Dr Kazan said: "These results encourage us to now turn to the Bari and Venice relics to attempt to show that the bone remains are from the same individual. We can do this using ancient palaeogenomics, or DNA testing. It is exciting to think that these relics, which date from such an ancient time, could in fact be genuine."
The relics held in Venice consist of as many as 500 bone fragments, which an anatomical study concluded were complementary to the Bari collection, suggesting that both sets of relics could originate from the same individual. It remains to be confirmed what fragments of the pelvis are contained amongst the Venice relics, if any.
The archaeologists' work has revealed that the bone has been venerated for almost 1700 years, making it one of the oldest relics that the Oxford team has ever analysed. As Radio carbon-dating technology has become more sophisticated in recent years, ancient relics have become more accessible in ways that previously would have been considered too invasive to study. Dr Kazan added: "Where once we needed physical portions of a bone sample, we can now test milligram size, micro-samples - opening up a new world of archaeological study."
In the 16th century stories about St Nicholas become popular, and the legend of Father Christmas was born. December 6 is known and celebrated in several European countries - particularly Holland, as St Nicholas Feast Day. On the eve of the feast, children leave out clogs and shoes to be filled with presents. Of the possible authenticity of the relic itself, Professor Higham concludes: "Science is not able to definitely prove that it is, it can only prove that it is not, however."
Explore further: Archaeologists may have discovered St. Nick's bones
More information: For more on the Oxford Relics Cluster go here: www.keble-asc.com/cluster/reli … uster/relics-cluster
||||| Historians and archaeologists have argued for generations about just where the bones of kindly St. Nicholas—the Christian Saint on which the legend of Santa Claus is based—are buried. Turkey, Italy and even Ireland have all made claims. Now, as Sean Coughlan at the BBC reports, researchers are turning to radiocarbon dating for answers, discovering at least one bit of bone claimed to be St. Nick’s is the correct age.
The bone is a fragment of pelvis that is currently owned by Father Dennis O’Neill of St. Martha of Bethany Church in Illinois. Researchers from University of Oxford dated the bone using the decay of carbon-14 as their timeline. Based on this analysis, they conclude that the bone hails from the 4th century A.D. St. Nicholas is believed to have died in 343 A.D., loosely supporting the claim of origin.
“Many relics that we study turn out to date to a period somewhat later than the historic attestation would suggest,” says Tom Higham of the Oxford Relics Cluster, who has examined many relics in the past and who tested the St. Nicholas bone, in a press release. “This bone fragment, in contrast, suggests that we could possibly be looking at remains from St. Nicholas himself."
However, actually confirming that the bone actually belonged to the saint is tricky, if not impossible. He led an interesting life; as bishop of Myra, a city in modern-day Turkey, he was known for his generosity and for leaving coins in the shoes of the poor. But what happened to his body after his death, is just as compelling. Saint Nicholas’s bones were interred at a church in Myra, present day Demre, after his death. But it's believed that in 1087, traders from the city of Bari in Italy broke into the crypt and stole his bones, bringing them to the basilica in their hometown where they are still revered.
Venice, however, claims that traders from their city stole the bones 1099. Then there’s the claim that Norman crusaders nabbed the bones, bringing them to Kilkenny, Ireland. Even more confusing, archaeologists in Turkey claimed in October that even if traders or crusaders did steal the bones from they church, they got the wrong guy. So the body of St. Nicholas might still be in his original tomb under the church in Demre.
So how did St. Nicholas’ pelvis end up in a Chicago suburb? Father O’Neill has amassed a collection of artifacts related to saints over many years. This particular fragment can by traced to Lyon, France. Interestingly, the remains in the church in Bari include only the left ilium, or upper part of the pelvis, while Father O’Neill’s fragment is from the lower left, raising the possibility that it might be from the same set of remains. Other research suggests that the 500 bone fragments venerated in Venice are complementary to the pieces held in Bari, which hints they might all belong to a single individual as well. But whether these fragments contain the rest of the pelvis still remains unknown.
Much more work needs to be done to proclaim St. Nick to be found. For one, researchers need to date more of the fragments to test whether they all come from the same period of time. DNA testing may also offer clues to the bones' late owner.
Even if the fragments all belong to the same person, connecting them to St. Nick might still be impossible. As Brian Handwerk reports for National Geographic, though Bari has the best claim for the bones, a dozen churches around the world contend they too have bits and pieces of his body.
This means that at least part of the story is true: Santa Claus is everywhere at once. | – Typically if you go around claiming to have a piece of Santa Claus' pelvis, you've earned yourself a psych evaluation. But it turns out a priest outside Chicago might actually have a case. The BBC reports scientists at the University of Oxford conducted the first-ever radiocarbon dating of a bone supposedly belonging to St. Nicholas and discovered that, if nothing else, it's the right age. The real St. Nick—who Smithsonian explains was a wealthy bishop known for leaving coins in the shoes of the poor—is believed to have died in 343 AD in what is now Turkey. The bone tested by Oxford scientists—a partial pelvis in the possession of the relic-collecting Rev. Dennis O'Neill—dated to the 4th century. “It’s very likely him," O'Neill tells the Chicago Sun-Times. "Pretty exciting.” Scientists wouldn't go that far. Dr. Georges Kazan tells the BBC the bone "could in fact be genuine," but there's no way to prove that. Bones purporting to belong to St. Nicholas can be found around the world, according to a press release. Most experts believe St. Nicholas' remains were stolen from their original resting place in Turkey in 1087 and taken to a church in Bari, Italy. But a church in Venice claims it has the true remains. There are also claims the remains are in Ireland, and O'Neill's pelvis actually came from a church in France. Scientists now want to conduct DNA tests on the bones to find out which come from the same person. (And if that weren't enough, archaeologists claimed in October they found St. Nicholas' remains undisturbed in a grave in Turkey.) |
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ARDMORE, Okla. - Officials have identified a woman who was killed after being attacked by seven dogs.
The Carter County Sheriff's Office says 52-year-old Tracy Garcia died after the dogs attacked her near her home last week.
“From what it appeared, about seven dogs had attacked her,” said Carter County Sheriff Chris Bryant.
As first responders on the scene tried to help the woman, the dogs turned on them.
“Unfortunately, yes, we had to shoot one dog,” said Bryant. “It did charge our deputies and to protect our deputies, as well as the medical personnel, we did have to put down a dog.”
The sheriff says the remaining dogs were euthanized at the owner’s request.
As far as charges go, Bryant says the investigation is on-going and the district attorney has been contacted. ||||| CARTER COUNTY, Okla. -- The victim of a deadly dog attack in Carter County last week has been identified.
The Carter County Sheriff said Tracy Garcia, 52, was mauled by seven of her neighbor's dogs Thursday evening near the intersection of Banyon and Mary Niblack roads, just east of Ardmore.
She later died from her injuries.
According to her obituary, Garcia is survived by a son and daughter. Her funeral was scheduled for Tuesday afternoon.
Sheriff Chris Bryant said all seven dogs involved in the attack were mixed breeds, and all were under 40 pounds. The initial report that a pit bull was among the dogs was inaccurate, he said.
One of the pets was put down by first responders; the others were later euthanized at the request of their owner.
"This is a bad situation, a very unfortunate situation," Bryant said. "Our thoughts and prayers go out to the family of the victims. This is just a bad deal all the way around."
The sheriff said he hopes to have the autopsy results and other relevant information ready for the district attorney's office by Tuesday morning. The DA will then review the documents to determine if the dogs' owner will face charges. ||||| Early reports said an Ardmore woman was brutally killed by dogs Thursday Night east of Ardmore.
The attack occurred on Banyon Road, just off Mary Niblack near the county line.
All seven of the dogs involved were rounded up by Ardmore police department's animal control officers. According to Ardmore Police Department records, the animals were taken to Westwood Veterinary Hospital, then were delivered deceased later to the Ardmore Animal Shelter. The veterinarian was not available yet for comment on the condition of the animals upon arrival.
Shelter Co-director Tena Layton said their examination showed six of the dogs were approximately a year old, with one possibly being the mother of those animals.
The oldest dog of the group was aged at about three years old by her teeth. All of the animals appeared to be a mix of Dachshund and some sort of terrier, Layton said. The oldest of the dogs was reportedly slightly larger and could have been mixed with Border Collie or similar. None of the dogs had legs longer than an adult’s hand per photos retained by the shelter.
All seven animals were heavily infested with fleas and ticks, Layton said. It is unclear at this time whether the animals suffered any other illnesses. The animals are currently being held at the Shelter pending release for cremation.
The Carter County Sheriff's office currently has an ongoing investigation regarding this incident. More information regarding the attack and the victim will be provided as it becomes available. ||||| WARNING: Images shown in video are graphic.
Carter County Sheriff Chris Bryant says Tracy Garcia, 52, was attacked and killed by a neighbor's dogs near her home on Banyon Road outside Ardmore Thursday night.
Deputies shot and killed one dog that charged them.
They took the other six to the Westwood Veterinary Hospital to be put down at the owners request.
The dogs were then sent to the Ardmore Animal Shelter.
"There were seven dogs - three were females, four of them were males," Dinwiddie said. "They all ranged from probably a year to about three years (old)."
The shelter's euthanasia technician Amanda Dinwiddie says six of the dogs are believed to be standard dachshund and terrier mix, one is believed to be a border collie mix.
None of the dogs weighed more than 40 pounds and taller than knee high.
"A predominant breed in these dogs is definitely standard dachshund," Dinwiddie said. "They have really noticeable characteristics like their knobby legs, knees, very short legged dogs and their coats."
Dinwiddie says the dogs were infested with fleas and ticks but didn't have any other visible health concerns.
"We were cleaning ticks off ourselves all day," Dinwiddie said. "They are very covered, you can tell they have been living out in the woods."
The vet hospital says the animals won't be tested for rabies, a decision Dinwiddie understands.
"If there was any possible issue of them biting someone else then it would've been (done) but the dogs are deceased as well as the victim so there's just no reason to go spend the thousands and thousands of dollars," Dinwiddle said.
Sheriff Chris Bryant says the attack is still under investigation and will be turned over to the District Attorney's office for review. ||||| ARDMORE, Okla. (AP) — An Oklahoma woman is dead after authorities say she was attacked by seven dogs.
Carter County Sheriff Chris Bryant says deputies were dispatched Thursday night to an area just east of Ardmore. Bryant says medical personnel were already on-scene treating the woman, but she later died at a hospital.
Bryant says the woman lived in the area, but he did not immediately release her name.
It's unclear what led to the attack. | – They weighed no more than 40 pounds each and reached just up to one's knees, but all together, a pack of seven dachshunds proved a deadly force in Oklahoma. Carter County Sheriff Chris Bryant says 52-year-old Tracy Garcia was mauled and killed Thursday night by her neighbor's dogs near her home outside Ardmore, KXII reports. When first responders arrived on the scene, at least one of the dachshunds turned on them, too, even charging toward the rescuers. "Unfortunately … we had to shoot one dog," Bryant says, per KFOR, adding they opened fire on it "to protect our deputies, as well as the medical personnel." After the attack, the owner requested the other six dogs be put down, too. The AP reports it's not clear what led to the attack. At the animal shelter where the dogs were sent after being euthanized, technician Amanda Dinwiddie said four of the dogs were males, three were females, and they all ranged in age from about a year to 3 years old; the older dog may have been the other dogs' mother, the shelter's co-director tells the Daily Ardmoreite. Six of the dogs were said to be a dachshund-terrier mix, while the older one was thought to be a dachshund-border collie mix. Dinwiddie adds the dogs were infested with fleas and ticks—"you can tell they have been living out in the woods"—but otherwise healthy. "This is just a bad deal all the way around," Bryant says, per KTEN. Whether the dogs' owner faces charges will be determined after the district attorney's office reviews Garcia's autopsy results. (Another woman got a dog to protect her family. It ended up killing her.) |
central pontine myelinolysis ( cpm ) is an acquired demyelinating lesion of the basis pontis that typically occurs after rapid correction of hyponatremia .
it is an uncommon condition with predilection for the central portion of the basis pontis , although axons in the putamina , caudate nuclei , thalami , cerebellum , splenium of the corpus callosum , and subcortical white matter are other extrapontine sites that are sometimes involved either separately or in concert with the pontine lesion [ 1 , 2 ] .
cpm is most often found in patients with chronic alcoholism , malnutrition , hyponatremia , liver disease , liver transplants , systemic hypotension and infections .
a 26-year - old hispanic male with history of alcohol abuse presented with acute onset diffuse abdominal pain .
there was a 1-month history of intermittent abdominal pain , lethargy , and early satiety with resulting 9 kg weight loss .
laboratory studies revealed hemoglobin and hematocrit of 11.1 g / dl and 32.4% , respectively , with a platelet count of 86,000 per microliter .
the only other abnormalities were serum sodium of 130 iu / l , aspartate aminotransferase and alanine transaminase at 152 and 166
iu / l , alkaline phosphatase at 186 iu / l and amylase and lipase at 86 and 105 u / l , respectively . on the night of admission ,
a computed tomography ( ct ) scan of the abdomen showed a large pancreatic mass of 12 11 6.5 cm in size encasing the second and third portions of the duodenum , extending retroperitoneally and abutting the adjacent inferior vena cava and abdominal aorta . during his hospital
stay , the patient underwent an endoscopic guided biopsy of the mass by the gastroenterology team and fine needle aspiration bone marrow biopsy .
the medical icu team decided to gently correct his sodium using salt tablets and normal saline .
1 . each value can be seen in online supplementary table 1 ( www.karger.com/doi/10.1159/000345225 ) .
an mri of the brain was performed on hospital day 8 for staging purposes and is displayed in fig .
although no lesions were demonstrated to be consistent with lymphoma , there were fluid attenuation inversion recovery ( flair ) and t2-weighted changes consistent with cpm .
following the new mri findings , the neurology team was consulted for a detailed exam .
typical symptoms include behavioral disturbances , confusion , mutism , dysarthria , dysphagia , bulbar and pseudobulbar paresis , hyperreflexia , quadriplegia , and seizures [ 2 , 4 ] .
locked - in state can occur and coma is uncommon [ 2 , 4 ] .
acute hyponatremia ( 48 h ) generally causes more severe symptoms as compared to chronic hyponatremia ( 48 h ) but individuals with chronic hyponatremia are at higher risk for developing cpm .
pathologically cpm is described as a symmetric , sharply demarcated lesion in the basis pontis .
there is a loss of oligodendrocytes , destruction of myelin sheaths and preservation of neuronal cell bodies and axons .
inflammation is absent and evidence of disruption of the blood - brain barrier may be present .
the lesion of cpm has a characteristic radiographic appearance . although ct may be normal for several days to 2 weeks
, the typical ct findings include symmetric hypo - dense areas in the basis pontis and extra - pontine regions with no associated mass effect .
an mri is more sensitive and on t2-weighted and flair images , cpm appears as a symmetric hyper - intense signal in the central pons .
on t1-weighted mri , the lesion is hypo - intense and non - contrast enhancing .
mri diffusion - weighted imaging is most sensitive and can detect lesions within 24 h of development of symptoms and shows a hyper - intense region .
the severity of the lesion does not correlate with the severity of symptoms but the lesion will decrease in size and intensity on t2-weighted and flair images as clinical symptoms subside
previous clinical and laboratory studies suggest that myelinolysis is due to cellular stress which is the result of fluctuating osmotic forces and ion shifts that lead to changes in cell volume and cell membrane function .
other clinical studies have shown that myelinolysis may be due to the brain 's overshoot of sodium during correction of hyponatremia or compression of myelin by edematous cellular elements [ 3 , 5 ] . in 1959 , adams et al .
we performed a pubmed search with the following keywords : asymptomatic , central , pontine , and myelinolysis in order to find other reports of asymptomatic cpm .
of the 29 results , we found only 6 previous case reports with english language abstracts of patients with alcoholism , malnutrition , or liver transplants that were diagnosed with asymptomatic cpm since 1995 [ 3 , 7 , 8 , 9 , 10 , 11 ] .
in addition , a postmortem study of 3,247 brains found 15 cases of cpm incidentally .
six had active lesions and 9 had remote lesions as defined pathologically . in the active group ,
5 individuals received rapid and sustained treatment of hyponatremia during the appropriate time frame . in patients who develop acute hyponatremia , the urinary sodium concentration is often greater than 40 mmol / l , and the plasma urea concentration is low , whereas in chronic hyponatremia , the urinary sodium concentration is usually less than 20
mmol / l , and the plasma urea concentration is often high . the decision to treat hyponatremia or not is still up for debate as some suggest only fluid restriction and reversal of any precipitating factor to manage these patients rather than more aggressive measures such as 0.9% saline . while the rate of correction of chronic hyponatremia is generally recommended to be slow to reduce the incidence of cpm , at least nine correction rates have been reported : from 23 mmol / l / day up to 25 mmol / l / day [ 15 , 16 ] .
the general consensus , however , is to correct no greater than 12 mmol / l / day .
mmol / l / day , demonstrating the difficulty in controlling sodium correction to prevent cpm .
moreover , it has been recognized that certain patients such as those who suffer from chronic alcoholism , as our patient did , or the malnourished are at higher risk for developing cpm despite of a slow correction .
this case clearly demonstrates that despite slow correction of hyponatremia , cpm can be an important consequence , especially for patients suffering from malnutrition or alcoholism .
although this patient did not demonstrate any neurological deficits , the fact that there were changes seen on mri should caution physicians in aggressively treating hyponatremia .
furthermore , if there is a decision to treat , then fluid restriction and reversal of precipitating factors ( i.e. diuretics ) should be used initially , unless there is concern for hypovolemia .
lastly , there are only a few reported cases of asymptomatic cpm and we hope to raise awareness of this entity .
dr . fekete received honoraria from medlink , inc . , and serves as consultant for teva neuroscience , inc . , and lundbeck , llc .
| introductioncentral pontine myelinolysis ( cpm ) is an acquired demyelinating lesion of the basis pontis that typically occurs after rapid correction of hyponatremia .
there are only a few reported cases of patients without symptoms that have demonstrated cpm on imaging.case presentationwe report the case of a 26-year - old hispanic male with history of alcohol abuse who was transferred to our medical center for acute onset diffuse abdominal pain . during his work up ,
a computed tomography scan demonstrated a large pancreatic mass .
he underwent an endoscopic guided biopsy which demonstrated a rare and aggressive natural killer t cell lymphoma .
his laboratory values were consistent with hyponatremia , which the medical team gently corrected .
an mri was performed for staging purposes which revealed findings consistent with cpm .
a full neurological exam demonstrated no deficits.materials and methodswe conducted a pubmed search using the following keywords : asymptomatic , central , pontine , and myelinolysis in order to find other case reports of asymptomatic cpm.resultsof the 29 results , only 6 previous case reports with english language abstracts of asymptomatic cpm were present since 1995.conclusiondespite slow correction of hyponatremia , cpm can be an important consequence , especially in patients with chronic alcoholism . although this patient did not demonstrate any neurological deficits , the fact that there were changes seen on mri should caution physicians in aggressively treating hyponatremia . furthermore ,
if there is a decision to treat , then fluid restriction and reversal of precipitating factors ( i.e. diuretics ) should be used initially , unless there is concern for hypovolemia . |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Airport and Airway Extension Act of
2011, Part IV''.
SEC. 2. EXTENSION OF TAXES FUNDING AIRPORT AND AIRWAY TRUST FUND.
(a) Fuel Taxes.--Subparagraph (B) of section 4081(d)(2) of the
Internal Revenue Code of 1986 is amended by striking ``July 22, 2011''
and inserting ``September 16, 2011''.
(b) Ticket Taxes.--
(1) Persons.--Clause (ii) of section 4261(j)(1)(A) of the
Internal Revenue Code of 1986 is amended by striking ``July 22,
2011'' and inserting ``September 16, 2011''.
(2) Property.--Clause (ii) of section 4271(d)(1)(A) of such
Code is amended by striking ``July 22, 2011'' and inserting
``September 16, 2011''.
(c) Effective Date.--The amendments made by this section shall take
effect on July 23, 2011.
SEC. 3. EXTENSION OF AIRPORT AND AIRWAY TRUST FUND EXPENDITURE
AUTHORITY.
(a) In General.--Paragraph (1) of section 9502(d) of the Internal
Revenue Code of 1986 is amended--
(1) by striking ``July 23, 2011'' and inserting ``September 17,
2011''; and
(2) by inserting ``or the Airport and Airway Extension Act of
2011, Part IV'' before the semicolon at the end of subparagraph
(A).
(b) Conforming Amendment.--Paragraph (2) of section 9502(e) of such
Code is amended by striking ``July 23, 2011'' and inserting ``September
17, 2011''.
(c) Effective Date.--The amendments made by this section shall take
effect on July 23, 2011.
SEC. 4. EXTENSION OF AIRPORT IMPROVEMENT PROGRAM.
(a) Authorization of Appropriations.--
(1) In general.--Section 48103 of title 49, United States Code,
is amended by striking paragraph (8) and inserting the following:
``(8) $3,380,178,082 for the period beginning on October 1,
2010, and ending on September 16, 2011.''.
(2) Obligation of amounts.--Subject to limitations specified in
advance in appropriation Acts, sums made available pursuant to the
amendment made by paragraph (1) may be obligated at any time
through September 30, 2011, and shall remain available until
expended.
(b) Project Grant Authority.--Section 47104(c) of such title is
amended by striking ``July 22, 2011,'' and inserting ``September 16,
2011,''.
SEC. 5. EXTENSION OF EXPIRING AUTHORITIES.
(a) Section 40117(l)(7) of title 49, United States Code, is amended
by striking ``July 23, 2011.'' and inserting ``September 17, 2011.''.
(b) Section 44302(f)(1) of such title is amended--
(1) by striking ``July 22, 2011,'' and inserting ``September
16, 2011,''; and
(2) by striking ``October 31, 2011,'' and inserting ``December
31, 2011,''.
(c) Section 44303(b) of such title is amended by striking ``October
31, 2011,'' and inserting ``December 31, 2011,''.
(d) Section 47107(s)(3) of such title is amended by striking ``July
23, 2011.'' and inserting ``September 17, 2011.''.
(e) Section 47115(j) of such title is amended by striking ``July
23, 2011,'' and inserting ``September 17, 2011,''.
(f) Section 47141(f) of such title is amended by striking ``July
22, 2011.'' and inserting ``September 16, 2011.''.
(g) Section 49108 of such title is amended by striking ``July 22,
2011,'' and inserting ``September 16, 2011,''.
(h) Section 161 of the Vision 100--Century of Aviation
Reauthorization Act (49 U.S.C. 47109 note) is amended by striking
``July 23, 2011,'' and inserting ``September 17, 2011,''.
(i) Section 186(d) of such Act (117 Stat. 2518) is amended by
striking ``July 23, 2011,'' and inserting ``September 17, 2011,''.
(j) The amendments made by this section shall take effect on July
23, 2011.
SEC. 6. ESSENTIAL AIR SERVICE REFORM.
(a) In General.--Section 41731(a)(1) of title 49, United States
Code, is amended--
(1) in subparagraph (A) by redesignating clauses (i) through
(iii) as subclauses (I) through (III), respectively;
(2) by redesignating subparagraphs (A) and (B) as clauses (i)
and (ii), respectively;
(3) in clause (i)(I) (as so redesignated) by inserting ``(A)''
before ``(i)(I)'';
(4) in subparagraph (A)(ii) (as so redesignated)--
(A) by striking ``determined'' and inserting ``was
determined'';
(B) by striking ``Secretary'' and inserting ``Secretary of
Transportation''; and
(C) by striking the period at the end and inserting a
semicolon; and
(5) by adding at the end the following:
``(B) is located not less than 90 miles from the nearest
medium or large hub airport; and
``(C) had an average subsidy per passenger of less than
$1,000 during the most recent fiscal year, as determined by the
Secretary.''.
(b) Limitation on Authority To Decide a Place Not an Eligible
Place.--Section 41731(b) of such title is amended--
(1) by striking ``Secretary of Transportation'' and inserting
``Secretary''; and
(2) by striking ``on the basis of a passenger subsidy at that
place or on another basis'' and inserting ``on any basis''.
(c) Exceptions and Waivers.--Section 41731 of such title is amended
by adding at the end the following:
``(c) Exceptions for Locations in Alaska.--Subsections (a)(1)(B)
and (a)(1)(C) shall not apply with respect to a location in the State
of Alaska.
``(d) Waivers.--The Secretary may waive subsection (a)(1)(B) with
respect to a location if the Secretary determines that the geographic
characteristics of the location result in undue difficulty in accessing
the nearest medium or large hub airport.''.
Speaker of the House of Representatives.
Vice President of the United States and
President of the Senate. | Airport and Airway Extension Act of 2011, Part IV - (Sec. 2) Amends the Internal Revenue Code to extend through September 16, 2011, increased excise taxes on aviation fuels, the excise tax on air transportation of persons and property, and the expenditure authority for the Airport and Airway Trust Fund.
(Sec. 4) Increases the authorization of appropriations for the period beginning on October 1, 2010, and ending on September 16, 2011, for airport planning and development and noise compatibility planning projects (known as airport improvement projects [AIPs]). Extends through September 16, 2011, the authority of the Secretary of Transportation to make new AIP grants.
(Sec. 5) Extends until September 17, 2011: (1) the pilot program for passenger facility fee authorizations at non-hub airports, and (2) disclosure requirements for large and medium hub airports applying for AIP grants.
Directs the Secretary to extend through September 16, 2011, the termination date of insurance coverage for domestic or foreign-flag aircraft. Grants the Secretary discretionary authority to further extend such coverage through December 31, 2011. Extends through December 31, 2011, the authority of the Secretary to limit air carrier liability for claims arising out of acts of terrorism.
Extends through September 16, 2011: (1) grant eligibility for airports located in the Marshall Islands, Micronesia, and Palau; (2) grants to state and local governments for land use compatibility AIPs; and (3) authority for approving an application of the Metropolitan Washington Airports Authority for an airport development grant or for permission to impose a passenger facility fee.
Amends the Vision 100 - Century of Aviation Reauthorization Act to extend through September 16, 2011: (1) the temporary increase to 95% of the federal government's share of certain AIP costs, and (2) funding for airport development at Midway Island Airport.
(Sec. 6) Revises essential air service (EAS) program eligibility requirements to limit such service to airports (except those in Alaska) that: (1) are located at least 90 miles from the nearest medium or large hub airport, and (2) had an average subisdy per passenger of less than $1,000. Authorizes the Secretary of Transportation to waive such requirements for a particular location if its geographic characteristics result in undue difficulty in accessing the nearest medium or large hub airport. |
hashimoto 's encephalopathy ( he ) , also called steroid - responsive encephalopathy associated with autoimmune thyroiditis ( sreat ) , is a rare condition that associates an encephalopathic state with an autoimmune - mediated lymphocytic infiltration of the thyroid gland ( hashimoto 's thyroiditis , ht ) .
a humoral autoimmune process is supported by the finding of antineuronal or anti--enolase antibodies .
other anti - cns autoantibodies could be involved in the occurrence of he , which might explain the variability of the clinical features .
a vasculitic process is not excluded in some patients , supported by stroke - like symptoms and necrotic sequelae observed on brain mri . although it is not certain whether they have a true physiopathologic meaning , the high titer of antithyroid antibodies leads to the diagnosis of he , after exclusion of other causes of encephalopathy .
the prevalence of he is estimated at 2.1/100,000 . since a large panel of unspecific neuropsychiatric symptoms can manifest during he and
( as confusion , memory loss , attention deficit , ) , psychiatric symptoms ( as hallucinations , psychosis , anxiety , agitation , jitteriness , ) , alteration of consciousness , seizure , tremor , ataxia , and stroke - like episodes can all be the first signs of the disease .
other authors reported seizures in 66% of he , including status epilepticus ( se ) in 12% .
focal , generalized , myoclonic seizures and se are described in association with he . as discussed by ferlazzo et al .
, se is generally resistant to antiepileptic drugs ( aeds ) and needs steroids to improve . to evaluate the outcome of he , only short series
steroid responsiveness is excellent in 90% , relapses following steroid dose reduction occur in 40% , immunosuppressive drugs ( isds ) are used in 10% , persistent cognitive symptoms remain in 15% , and uncontrolled relapses persist in 10% . concerning the issue of se as a complication of he ,
only a few cases are reported in the literature with often a short follow - up period , rendering their late outcome not well known .
in 2006 , a 26-year - old woman without relevant medical story developed tremor , confusion , agitation , and blurred vision during a few weeks . a first episode of refractory generalized convulsive status epilepticus ( gcse ) followed and required anesthetic agents to improve . a prolonged postictal status with bradypsychia , ataxia , and tremor followed .
she recovered but promptly had a second episode of refractory gcse despite oral phenytoin and required anesthetic agents again .
the brain tc99m - bicisate spect reported right frontotemporal hypoperfusion and a focal right paramedian frontal hyperperfusion .
a mild elevation of protein content without oligoclonal bands was found in the cerebrospinal fluid .
the autoimmune screening in the serum disclosed high titers of antithyroglobulin ( 274 iu / ml , normal < 60 iu / ml ) and antithyroperoxidase ( 602.8 iu / ml , normal < 60 iu / ml ) antibodies , with euthyroid status .
onconeural antibodies ( anti - hu , anti - yo , and anti - ri ) were negative .
the eeg normalized rapidly after intravenous methylprednisolone ( 1 g / day ) , and the patient recovered .
her cognitive functions were almost normal with small deficits for free recall ( episodic memory ) , selective attention , and verbal fluency ( table 1 ) .
ten months later , steroids were progressively reduced because of side effects ( osteoporosis , cushing - like syndrome , diabetes ) .
phenytoin and steroids were discontinued after six courses of cyclophosphamide . for 3 years , she was free of treatment and seizures .
postural tremor , nervousness , and anxiety persisted . in 2010 , she presented a short collapse without prolonged postictal status and a transient slowed eeg .
, she relapsed into a gcse resistant to lormetazepam , phenytoin , levetiracetam , and intravenous methylprednisolone .
different antiepileptic drugs were used without success ( phenytoin , phenobarbital , levetiracetam , lacosamide , and midazolam ) .
the brain mri revealed t2 and flair bilateral frontal hyperintensity spreading to thalamic and mesiotemporal areas , without gadolinium enhancement ( fig . 1 ) .
the eeg showed successively a drug - induced burst - suppression state , generalized periodic epileptiform discharges , a diffuse slowing with subtle seizures of frontal origin , and a progressive return of alpha rhythm ( fig . 2 ) .
two years later , frontal behavior , memory loss , and loss of autonomy persisted .
the neuropsychological tests showed cognitive slowing , poor spontaneous speech , apathy , poor orientation , episodic memory loss , perseverations , confabulations , and impairment of visuospatial , attention , and executive functions ( table 1 ) .
myoclonia and transient loss of consciousness relapse under 8 mg a day of oral methylprednisolone . in 2013 , she continues to use chronically antiepileptic drugs ( levetiracetam , phenytoin , and phenobarbital ) and low dose of oral methylprednisolone .
we report the 7-year follow - up of a young woman who presented with recurrent status epilepticus associated with hashimoto 's encephalopathy .
this diagnosis is sustained by high titer of antithyroid antibodies and the exclusion of other toxic , metabolic , infectious , or paraneoplastic etiologies . through lack of typical features of limbic encephalitis or n - methyl - d - aspartate receptor antibody ( nmdar - ab ) encephalitis , a complete screening of antibodies ( ab ) against neuronal surface antigens ( as voltage gate potassium channel ( vgkc ) complex ab , glutamic acid decarboxylase ( gad ) ab , -amino-3-hydroxy-5-methyl-4-isoxasolepropionic acid receptor ( ampar ) ab , and gamma - aminobutyric acid b receptor ( gababr )
only a few cases of status epilepticus associated with he have been reported , and some are shown in table 2 . including our cases , all present the clinical diffuse progressive type of he proposed by kothbauer - margreiter et al . with first symptoms equally distributed between thyroid dysfunction , behavioral changes , or se .
this distribution emphasizes the clinical variability and the necessity to look for antithyroid ab in the case of se of unknown origin .
her evolution was first characterized by a frontal eeg and spect focalization in the course of a gcse episode .
later , while spike wave discharges showed a diffuse spreading leading to an especially prolonged ncse , diffuse mesiotemporal and frontal postictal edema was observed on the brain mri .
seizures of frontal origin or temporal origin have both been reported to be associated with he . among the patients listed in table 2 and using different diagnostic procedures ( brain mri , pet scan , spect , or eeg ) ,
frontal dysfunction is more frequently observed ( 6/10 ) than mesiotemporal dysfunction ( 1/10 ) . from a therapeutic point of view , her evolution was marked by successive steroid responsiveness , steroid dependence , prolonged remission after cyclophosphamide courses , late relapse of steroid - resistant symptoms , and thereafter persisting steroid dependence .
no correlation could be made between the occurrence of steroid - resistant symptoms and a delay in the beginning of intravenous methylprednisolone .
steroid - resistant se as a complication of he seems to be infrequent ( 2/11 , including our patient and one patient in table 2 ) but does not exclude the diagnosis . as reported by other authors , a correlation has not been observed between relapses and the level of antithyroid - ab ( fig .
3 ) , sustaining the hypothesis that they do not play a part in the physiopathological development of he .
the outcome of most patients ( 8/11 ) listed in table 2 is favorable but has been commonly observed in a short follow - up period and often with ongoing steroid or isd use , making the conclusions debatable . early ( 2/11 ) and
two ( including our patient ) remain cognitively deficient as sequelae of prolonged steroid - resistant se . in conclusion
, this case report emphasizes the possible frequent relapses of se as a complication of he and the possible evolution towards steroid - resistant se .
clinicians should be aware that relapses can occur early or even late after tapering of steroid or isd use ; therefore , a long follow - up period should be advisable .
moreover , since the antithyroid antibodies could not been used as markers of encephalopathy 's relapses , the question of the continuation of the immunomodulatory of immunosuppressive drugs remains an open debate . | hashimoto 's encephalopathy ( he ) is an infrequent disease with no well - known physiopathology .
status epilepticus is rarely reported in association with he .
we describe the 7-year evolution of a young woman who presented with recurrent status epilepticus as the main complication of he .
this evolution was especially marked by the occurrence of steroid - refractory symptoms and a poor outcome with persistent cognitive and behavioral consequences .
we point out that the frontal lobes are especially implicated in these symptoms .
this patient highlights the risk of multiple relapses and the need for a long follow - up period .
we describe her clinical and paraclinical features , compare this patient to similar case reports , and comment on her outcome . |
approximately 274,000 new cases annually are diagnosed worldwide with only a 50% survival rate over 5 years despite improved methods of diagnosis and therapy .
prevention of this malignancy requires a better understanding of its carcinogenesis process [ 2 , 3 ] .
chemokines , a group of small ( approximately 817 kda ) chemotactic cytokines that bind to specific g - protein - coupled seven - span transmembrane receptors , are essential mediators of leukocyte migration in the immune system .
chemokines and their receptors play important roles in inflammation , infection , tissue injury , allergy , and cardiovascular diseases .
recently , the importance of chemokines and chemokine receptors has been highlighted in the initiation and progression of cancers [ 4 , 5 ] . among those chemokines and their receptors ,
the stromal cell - derived factor-1 ( also cxcl12 ) and its cx chemokine receptor 4 ( cxcr4 ) , a protein frequently overexpressed on the surface of human tumor cells of epithelial origin , have received considerable attention . to date
, cxcr4 has been demonstrated to be overexpressed in more than 23 human cancers , including breast cancer , ovarian cancer , and oral cancer .
although cxcr4 is expressed in a broad array of tissues , cxcr4 expression is low or absent in many normal tissues , such as breast and ovary [ 6 , 7 ] .
significant correlation between cxcr4 expression and lymph - node metastasis was found in oscc patients .
treatment with cxcl12 enhanced the motility and invasiveness of oscc cells expressing cxcr4 . although recently attentions have been paid to the relationship between cxcr4 and oral cancer , until now , no report focuses on the alterations of cxcl12/cxcr4 axis in premalignant stage of oral cancer .
leukoplakic oral epithelia provide a useful model for exploring the molecular mechanisms of oral carcinogenesis [ 3 , 9 ] . in this study
, we set out to evaluate the protein expressions of cxcl12 and cxcr4 by immunohistochemistry in surgically resected normal oral epithelia , olk specimens with epithelial dysplasia , and oscc tissues .
then , the relationship of cxcl12 and cxcr4 in oral premalignant and malignant lesions was investigated .
a total of 77 subjects , including 24 olk patients , 40 oscc patients , and 13 healthy persons , were enrolled in the present study from guanghua school of stomatology , sun yat - sen university , china .
no subjects had radiotherapy , chemotherapy , or other interventional palliative or therapeutic measures prior to sampling .
all subjects participated in this study with written consents , and the project was approved by the institutional review board .
all the surgically resected specimens were formalin fixed and paraffin - embedded using conventional histopathological techniques for both histopathological examination and subsequent immunohistochemistry analysis .
histopathological evaluation was performed according to the who criteria for histological typing of cancer and precancer of the oral mucosa by the department of pathology , guanghua school of stomatology .
the polyclonal primary rabbit antibodies against cxcl12 ( 1 : 400 , abcam inc . ,
cambridge , ma , uk ) and polyclonal primary goat antibodies against cxcr4 were used ( 1 : 300 , abcam inc . ,
immunohistochemistry was performed using the superpicture , a 3rd gen ihc detection kit ( invitrogen , us ) , and polink-2 plus polymer hrp detection system for goat primary antibody ( golden bridge international inc . , us ) according to the manufacturer 's recommendations .
4-m sections of paraffin - embedded specimens were deparaffinized in xylene ( twice ) and treated with a graded series of alcohol ( 100% , 95% , and 80% ethanol / double - distilled h2o2 ( v / v ) ) , and rehydrated in phosphate buffered saline ( pbs , ph 7.4 ) .
antigen retrieval was performed by incubating tissue sections immersed in 0.01 m sodium citrate buffer ( ph 6.0 ) in a microwave oven .
endogenous peroxidase was inactivated using 3% hydrogen peroxide for 10 min . after rinsing with pbs ,
the sections were incubated with polyclonal primary antibodies at 37c for 40 min ( cxcl12 ) or at 4c overnight ( cxcr4 ) . after washing with pbs for 5 min
, the sections were incubated for 10 min with biotinylated secondary antibody , washed with pbs , then incubated for 10 min with the streptavidin - horseradish peroxidase ( hrp ) solution , which binds to the biotin - labelled secondary antibody present to the tissue .
after pbs rinsing , staining of sections was performed by incubation for 5 min with 3,3-diaminobenzidine tetrahydrochloride ( dab ) in h2o2 . after washing with water
negative controls for each biopsy were processed in the same manner , using pbs instead of the primary antibody .
human spleen tissue and hepatocarcinoma tissue were used as positive controls for cxcr4 and cxcl12 , respectively .
expressions of cxcr4 and cxcl12 were quantified using a visual grading system based on the extent of staining ( percentage of positive cells graded on scale from 0 to 4 : 0 , < 5% ; 1 , 525% ; 2 , 2550% ; 3 , 5075% ; 4 , > 75% ) and the intensity of staining ( graded on a scale of 03 : 0 , none ; 1 , weak staining ; 2 , moderate staining ; 3 , strong staining ) . five representative fields at 400 magnification
a weighted score was assigned to each case by multiplying the score for the percentage of positive cells by the staining intensity score .
cases with a weighted score of less than 1 were considered negative ; otherwise they were considered positive .
chi - square analysis was used to estimate statistical difference of positive ratios among different groups during oral carcinogenesis .
probability value of p < 0.05 ( two - sided ) was accepted as statistically significant for all statistical tests carried out using spss version 13.0 software ( spss inc . , chicago , il , usa ) .
cxcr4 was expressed in 9 out of 24 olk cases ( 37.5% ; figure 1 ) .
of the 40 oscc cases , 24 ( 60% ) had uniformly detectable cxcr4 immunostaining .
however , the positive ratio of cxcr4 was only 15.4% ( 2 of 13 cases with weak staining ) in normal tissue .
no significant difference of cxcr4 positive ratio was found between normal tissue and olk , but in oscc the positive ratio increased and was significantly higher than that in normal epithelia ( p = 0.005 < 0.05 ) , without difference from olk tissues ( p = 0.081 > 0.05 ) .
cxcr4 staining showed a predominantly cytoplasmic distribution and some was also detected in the cellular nucleus ( figure 2 ) .
most normal tissues displayed little or undetectable cxcr4 expression . in both dysplastic and cancerous oral epithelia , the cxcr4 staining was distinct and spread in all the cell layers .
furthermore , mild - moderate staining could also been observed in some vascular endothelial cells within lamina propria and submucosa of dysplastic and cancerous oral epithelia .
expression of cxcl12 was observed in 12 of 24 olk ( 50% ; p = 0.01 < 0.05 ) cases and 25 of 40 oscc cases ( 62.5% , p = 0.001 < 0.05 ) , with significant difference from that in normal epithelia ( 1 of 13 cases , 7.7% ; figure 1 ) , respectively .
no significant difference was indicated between olk and oscc tissues ( p = 0.51 > 0.05 ) .
data analysis found that in 8 olk and 20 oscc specimens , which displayed positive staining of cxcr4 , expression of cxcl12 could also been detected ( table 1 ) .
significant relationship between cxcl12 expression and cxcr4 expression was found both in olk ( p = 0.003 < 0.05 ) and oscc specimens ( p = 0.001 < 0.05 ) .
recently , studies revealed that cancer epithelial cells were producing higher levels of a number of chemokines compared with normal epithelial cells and were also expressing high levels of a series of chemokine receptors , to establish a tumor - promoting microenvironment , facilitating tumor - associated angiogenesis and metastasis .
our previous study indicated that cxcr7 expression might be involved in oral carcinogenesis . in this study
, we demonstrated for the first time changes of cxcl12/cxcr4 chemokine axis in oral premalignant lesions and their potential roles in oral carcinogenesis .
our data were similar to that of two previous reports , which showed that the positive staining ratios were 62.6% and 57.3% in oscc patients , respectively [ 12 , 13 ] .
ishikawa et al . found a significant correlation between the expression of cxcr4 and hif-1 alpha in oscc tissues .
hif-1 is a heterodimeric transcription factor responsive to oxygen concentrations in tissues and has been shown to upregulate cxcr4 expression .
our results also showed that expression of its ligand cxcl12 was observed in 62.5% of 40 oscc cases . in 24 cxcr4-positive cases of oscc , cxcl12 , and cxcr4
were coexpressed in 20 cases . when compared with normal tissue , both cxcr4 and cxcl12 positive ratios in oscc
furthermore , of the 24 oral premalignant lesions ( olk cases ) , data analysis found that 37.5% displayed cxcr4 positive staining and 50% displayed cxcl12 positive staining .
although cxcr4 positive ratio showed no significant difference between olk and normal epithelia , the positive ratio of cxcl12 increased significantly from normal epithelia . in 9 cxcr4 positive cases of olk ,
further data analysis still found a significant relationship between cxcl12 expression and cxcr4 expression in olk , just similar to that in oscc tissues .
all those demonstrated that cxcl12/cxcr4 axis might begin playing roles from early steps of oral malignant transformation and contribute to the progress of oral carcinogenesis .
binding of cxcl12 to cxcr4 could trigger activation of many downstream targets , including erk1/2 , mapk , jnk , and akt effectors .
cxcl12/cxcr4 axis activated extracellular signal - regulated kinase ( erk)1/2 and akt / protein kinase b ( pkb ) in oscc cells , and their synthetic inhibitors attenuated the chemotaxis by sdf-1 .
sdf-1 also activated src family kinases ( sfks ) , and its inhibitor pp1 diminished the sdf-1-induced chemotaxis and activation of both erk1/2 and akt / pkb .
ligand - stimulated chemotaxis is accompanied by cytoskeletal rearrangements , actin polymerization , polarization , pseudopodia formation , and integrin - dependent adhesion to endothelial cells and other biologic substrates [ 1618 ] .
until now , very few reports concerned the biological functions and related signaling pathways of cxcl12/cxcr4 axis in the progression of oscc .
cxcr4-knockdown oscc cells showed reduced invasiveness and grew significantly slower than the vector - infected control cells .
cxcr4 promoted oscc migration and invasion through inducing expression of mmp-9 , 13 via the erk signaling pathway [ 20 , 21 ] .
all these suggest that the downregulation of cxcr-4 induces antiproliferative and antiinvasive effects in oscc and that cxcr-4 might be a useful target molecule for the treatment of oscc .
uchida et al . showed that subcutaneous administration of amd3100 ( cxcr4 inhibitor ) significantly inhibited the lymph node metastases of oscc cells when they were inoculated into the masseter muscle of nude mice .
taken together , these findings support the hypothesis that cxcl12/cxcr4 may play important roles in oral premalignant stages , contributing to the progress of oral carcinogenesis .
however , much about the mechanisms of cxcl12/cxcr4 axis in oral carcinogenesis still let to be known .
notably , blockage of cxcr4 as well as its ligands cxcl12 during oral cancer promotion could be employed as a new therapeutic strategy in future . | objective . the chemokine receptor cxcr4 and its ligand cxcl12 have been suggested to play important roles in the initiation or progression of cancers .
the goal of the present study was to investigate alterations of cxcl12/cxcr4 in oral premalignant lesions and oral squamous cell carcinoma ( oscc ) .
methods . in 13 normal oral epithelia ,
24 dysplastic oral leukoplakia ( olk ) , and 40 oscc specimens , expressions of cxcl12 and cxcr4 were evaluated by immunohistochemistry .
results .
cxcr4 was expressed in 37.5% of olk and 60% of oscc .
cxcl12 was detected in 50% of olk and 62.5% of oscc . in olk
, cxcr4 positive ratio showed no significant difference from normal epithelia , but the cxcl12 positive ratio was significantly higher .
significant relationship between cxcl12 and cxcr4 was found both in olk and oscc . conclusion .
our results indicated that cxcl12/cxcr4 axis may play roles from early steps of oral malignant transformation and contribute to the progress of oral carcinogenesis . |
Relatives mourn holding a portrait of Gurcharan Singh, one of the 38 Indian workers whose bodies were found buried northwest of Mosul, in Jalal Usma village in the northern Indian state of Punjab, Tuesday,... (Associated Press)
Relatives mourn holding a portrait of Gurcharan Singh, one of the 38 Indian workers whose bodies were found buried northwest of Mosul, in Jalal Usma village in the northern Indian state of Punjab, Tuesday, March 20, 2018. Iraqi authorities have found the bodies of 38 Indian workers abducted when Islamic... (Associated Press)
BAGHDAD (AP) — The dirt mound in the dry hills outside the village of Badush was known as a place where Islamic State fighters had buried some of their enemies after they overran much of northern Iraq nearly four years ago. But it was only when Iraqi authorities began digging last summer that the identity of the victims became clear.
They found the bodies of men with long black hair and silver bracelets known as karas that are worn by followers of the Sikh religion. On Tuesday, India's foreign minister confirmed the mass grave contains the bodies of 39 Indian construction workers abducted shortly after the area fell to the extremists.
Iraqi and Indian authorities said 38 of the bodies had been positively identified through DNA analysis. All were Indian, and all had been shot, many in the head. IS likely killed them for their religious beliefs.
DNA analysis has not been completed on the last body.
The killing was a "heinous crime carried out by Daesh terrorist gangs," Najiha Abdul-Amir al-Shimari, the head of Iraq's Martyrs Establishment, told reporters, using an Arabic acronym for the group.
Those killed were "citizens of the friendly Indian state. Their dignity was supposed to be protected, but the forces of evil wanted to defame the principles of Islam," said al-Shimari, whose government body documents those killed by IS.
While authorities have not said when they believe the group was killed, the bodies were badly decomposed and had clearly been buried for a long time, Iraq's forensic director, Zaid Ali Abbas, told The Associated Press. He also described how the men had been shot.
The workers, most from northern India, had been employed by a construction company operating near the northern city of Mosul. Around 10,000 Indians lived and worked in Iraq at the time.
In the first days after Mosul was captured, their relatives back in India began to receive panicked phone calls, with the men begging for help.
"Tajinder spoke to us once on the phone after he was kidnapped," said Tevinder Singh, whose nephew Tajinder Singh was among those killed. "We never heard from him again."
She said the Indian government did not contact the family to tell them his body had been identified. Instead, they got the news when Foreign Minister Sushma Swaraj announced it in a Parliament speech on Tuesday.
Dozens of mass graves have been discovered in territory once held by IS, though Iraq's government has only been able to examine a handful of them. Iraqi officials say they lack the resources and trained personnel to properly exhume so many sites.
At the height of its power, IS controlled nearly a third of the country. In recent years, Iraqi forces backed by a U.S.-led coalition have gradually driven the militants from all the territory they once held. The area around Badush was retaken last summer.
Search operations led to the mound of dirt near Badush, where local residents said bodies had been buried by IS, Swaraj said in Parliament.
Iraqi authorities used radar to verify that the mound was a mass grave, she said, and then exhumed the bodies. Indian authorities then sent DNA samples from relatives of the missing workers.
Forty Indians were captured by the militants, though one man managed to escape.
"It is indeed a moment of deep grief and sadness for us," India's ambassador to Iraq, Pradeep Singh Rajpurohit, told reporters in Baghdad. "India strongly condemns terrorism in all forms and manifestations and stands in solidarity with the government and the people of Iraq in their fight against terrorism."
He said the bodies will be sent back to India "in a couple of weeks or so."
Harjit Masih, the only Indian survivor, has long said the rest of the group had been killed. He said they had all been held for a number of days, then taken outside and ordered to kneel. Then the militants opened fire.
"They were killed in front of my eyes," he told reporters Tuesday in his north Indian village. He was shot in the thigh but managed to escape.
Iraq, which is in the midst of an economic crisis, is also struggling to rebuild after more than three years of grueling war against the militants. The fight against IS has cost Iraq more than $1 billion in destroyed infrastructure, officials say.
___
Associated Press writer Ashok Sharma in New Delhi contributed to this report. ||||| Bodies of 39 Kidnapped Indian Workers Found In Mass Grave In Iraq
Enlarge this image toggle caption Prabhjot Gill/AP Prabhjot Gill/AP
For years Harjit Masih has been talking about what happened outside of the Iraqi city of Mosul, the Associated Press reported. He and 39 other Indian men — all construction workers working on the Mosul University campus — had been kidnapped by members of ISIS as the extremist group waged its assault on the city.
The Sikh men were held captive for a handful of days then, Masih told Fountain Ink, they were forced to kneel shoulder to shoulder and shot multiple times at close range. Masih, who was shot in the thigh, was the lone survivor and managed to escape. Eventually, he made his way back to India, where until now the government's highest officials insisted there was no proof all the other prisoners were dead.
"They were killed in front of my eyes," he said from his home in a northern Indian village on Tuesday, the same day India's foreign minister, Sushma Swaraj, told parliament that DNA analysis of remains found in a mass grave near the village of Badush prove that the men who were abducted in 2014 were killed, The Guardian said.
"With full proof I can say these 39 are dead," Swaraj told reporters, adding that the missing workers had been murdered by ISIS, according to The Telegraph.
The AP said the bodies were found under a dirt mound after Iraqi authorities found evidence of the grave last summer using radar equipment. Once the bodies were exhumed, Indian authorities sent DNA samples from relatives of the missing workers. All but one have been identified.
Among the artifacts discovered at the site were ID cards, non-Iraqi shoes and religious bracelets.
In the days leading up to their disappearance, the AP reported many of the men made panicked phone calls to their relatives back in India, pleading for help to escape the ISIS-controlled region.
As a result, as NPR reported, anxious families began swamping government hotlines. "A majority of the Indians kidnapped in Iraq hail from Punjab," Punjab's deputy chief minister Sukhbir Singh Badal told NPR. "We are really worried ... The federal government must take every necessary action to bring [them] back home," he said at the time.
But The Telegraph reported, the Indian government never received any ransom demands or other direct communication from the kidnappers.
Swaraj, has been roundly criticized by members of the opposing party "for giving false hope to the nation." But she defended the decision to wait until this week to declare the men dead, insisting the government needed proof.
"It would have been a sin had we handed over anybody's body claiming it to be those of our people, just for the sake of closing files," she said.
The AP says dozens of mass graves like the one found outside of Badush have been discovered in territories previously held by ISIS. However, the Iraqi government says it doesn't possess the resources or trained personnel to examine all of them.
The Indian government said the identified bodies will be flown home after formalities are completed in Iraq. | – In the days after Mosul fell to ISIS, 40 Indian construction workers who'd been on assignment on the Mosul University campus were kidnapped. Only one, Harjit Masih, managed to survive after what he says were four days in captivity in June 2014. He was shot in the thigh; the rest, he says, got bullets, mostly to the head. NPR reports the Indian government had for years countered that, maintaining some could still be alive. Proof to the contrary has now come: The AP reports that a dirt mound outside the village of Badush that had been a rumored mass grave used by ISIS has turned out to be so. Iraqi authorities began excavating there in the summer after radar indicated there were human remains within, and they unearthed not just those remains. They also found ID cards, what NPR calls "non-Iraqi shoes," and karas, the silver bracelets Sikhs wear. DNA analysis has now led to 38 positive identifications, with the last one pending. "With full proof I can say these 39 are dead," Sushma Swaraj, India's foreign minister, said Tuesday. Iraq's forensic director says the men were indeed shot, and that the condition of their remains indicated they'd been buried for a long period, though he didn't offer a date. India's ambassador to Iraq says the bodies will be returned home in the coming weeks. The Guardian notes Swaraj caught flak over the government's delay in declaring the men dead. Her defense: "It would have been a sin had we handed over anybody's body claiming it to be those of our people, just for the sake of closing files." |
Results During 3 500 004 person years of follow-up between 2004 and 2013 (median 7.2 years), a total of 11 820 men and 8404 women died. Absolute mortality rates according to spicy food consumption categories were 6.1, 4.4, 4.3, and 5.8 deaths per 1000 person years for participants who ate spicy foods less than once a week, 1 or 2, 3 to 5, and 6 or 7 days a week, respectively. Spicy food consumption showed highly consistent inverse associations with total mortality among both men and women after adjustment for other known or potential risk factors. In the whole cohort, compared with those who ate spicy foods less than once a week, the adjusted hazard ratios for death were 0.90 (95% confidence interval 0.84 to 0.96), 0.86 (0.80 to 0.92), and 0.86 (0.82 to 0.90) for those who ate spicy food 1 or 2, 3 to 5, and 6 or 7 days a week, respectively. Compared with those who ate spicy foods less than once a week, those who consumed spicy foods 6 or 7 days a week showed a 14% relative risk reduction in total mortality. The inverse association between spicy food consumption and total mortality was stronger in those who did not consume alcohol than those who did (P=0.033 for interaction). Inverse associations were also observed for deaths due to cancer, ischemic heart diseases, and respiratory diseases.
The beneficial effects of spices and their bioactive ingredients such as capsaicin have long been documented in experimental or small sized population studies. For example, an ecological study showed that populations with a higher consumption of spices have a lower incidence of cancer. 4 The ingestion of red pepper was found to decrease appetite and energy intake in people of Asian origin and white people and might reduce the risk of overweight and obesity. 5 6 In addition, the bioactive agents in spices have also shown beneficial roles in obesity, cardiovascular and gastrointestinal conditions, various cancers, neurogenic bladder, and dermatological conditions. 7 8 9 Moreover, spices exhibit antibacterial activity and affect gut microbiota populations, which in humans have been recently related to risks of diabetes, cardiovascular disease, liver cirrhosis, and cancer. 10 11 12 These data collectively suggest that spices may have a profound influence on morbidities and mortality in humans; however, the evidence relating daily consumption of spicy foods and total and disease specific mortality from population studies is lacking.
Spices have been an integral part of culinary cultures around the world and have a long history of use for flavoring, coloring, and preserving food, as well as for medicinal purposes. The increased use of spices as flavorings in foods is a major trend worldwide. 1 2 In China, chilli pepper is among the most popular spicy foods consumed nationwide. 3
Subgroup analyses were conducted separately among participants who did and did not report fresh chilli pepper as one of their commonly used spices. We compared both with those who ate spicy foods less than once a week. We also examined the associations of spicy food consumption with total mortality among prespecified baseline subgroups based on age (<50, 50 to 59, or ≥60), smoking status (regular smoker, or not), alcohol consumption (regular drinker, or not), level of physical activity (categorized using tertile cut-offs), and body mass index (<24.0, 24.0 to 27.9, or ≥28.0). The tests for interaction were performed by means of likelihood ratio tests, which involved comparing models with and without cross product terms between the baseline stratifying variable and spicy food consumption as an ordinal variable.
To examine the robustness of our findings, we also conducted several sensitivity analyses: additionally adjusting for occupation and household income; additionally adjusting for histories of chronic hepatitis or cirrhosis, peptic ulcer, and gallstone or cholecystitis; adjusting for a 13 level detailed smoking variable, which incorporated the information on amount of smoking in regular smokers and the time since quitting in former smokers, instead of a four level smoking variable; excluding participants dying during the first two years of follow-up; excluding participants who had diabetes at baseline; excluding participants who reported exclusive use of other spices instead of any types of chilli; stratifying analyses by rural or urban residence; and stratifying analyses by follow-up duration (<3 or ≥3 years).
Multivariate models were adjusted for established and potential risk factors for death: age (continuous, serving as the underlying timescale); sex (male or female); level of education (no formal school, primary school, middle school, high school, college, or university or higher); marital status (married, widowed, divorced or separated, or never married); alcohol consumption (non-drinker, occasional drinker, former drinker, or regular drinker); smoking status (never smoker, occasional smoker, former smoker, or regular smoker); physical activity in MET hours a day (continuous); body mass index (continuous); intake frequencies of red meat, fresh fruits, and vegetables (daily, 4-6 days/wk, 1-3 days/wk, monthly, or rarely or never); prevalent hypertension and diabetes at baseline (presence or absence); menopausal status (for women only, premenopausal, perimenopausal, or postmenopausal); and status of family history of cancer, heart attack, stroke, or diabetes (presence or absence). We adjusted for the family history variables only in the corresponding analysis of cause specific mortality.
We measured person years from baseline (2004–08) until the date of death, loss to follow-up, or 31 December 2013, whichever occurred first. Cox proportional hazards regression models were used to estimate the hazard ratios and 95% confidence intervals of mortality for spicy food consumption, with age as the underlying time scale. We accounted for the group specific effect of 10 survey sites on the hazard function by stratifying on the survey site variable in the Cox model.
Trained staff blinded to baseline information classified any deaths occurring among participants by using ICD-10 codes (international classification of diseases, 10th revision). The deaths were grouped into seven categories: cancer (C00-C97), ischemic heart diseases (I20-I25), cerebrovascular diseases (I60-I69), diabetes mellitus (E10-E14), diseases of the respiratory system (J00-J99), infections (A00-B99), and all other causes. Losses to follow-up in this study refer to participants whose permanent registered residence was no longer in the study area, who could not be contacted after at least three reasonable efforts within one year, or who could be contacted but their new residence was out of the jurisdiction of the regional coordinating center.
We ascertained vital status by means of linkage with local disease surveillance points system death registries 15 and residential records. To minimize the under-reporting of deaths and to identify participants who had moved permanently out of the study areas, we also carried out separate active follow-up annually by reviewing residential records, visiting local communities, or directly contacting participants. 14 The causes of death were sought chiefly from official death certificates that were supplemented, if necessary, by a review of the medical records or undertaking a verbal autopsy using a validated instrument for those with an ill defined or unknown cause of death reported. The electronic linkage to the national health insurance claim databases started in 2011, which has become an important means of follow-up and helped to improve the accuracy of diagnosis and phenotyping of reported conditions, outcome adjudication, and further data collection. Linkage to local health insurance databases has been achieved for about 95% of the participants in 2013. Participants from both urban and rural areas had similar proportions of successful linkage to health insurance databases. Linkage to local health insurance database was renewed annually. Participants who failed to be linked to local health insurance database were actively followed annually by staff to ascertain their status, including hospital admission, death, and moving out of the study area. Linkage to a local health insurance database has become an important supplementary way of ascertaining deaths.
At baseline, trained staff measured body weight, height, and blood pressure using calibrated instruments. Body mass index was calculated as weight (kg)/(height (m) 2 . A stepwise on-site testing of plasma glucose level was undertaken using the SureStep Plus meter (LifeScan; Milpitas, CA). Prevalent hypertension was defined as a measured systolic blood pressure of 140 mm Hg or more, a measured diastolic blood pressure of 90 mm Hg or more, self reported diagnosis of hypertension, or self reported use of antihypertensive drugs at baseline. Prevalent diabetes was defined as a measured fasting blood glucose concentration of 7.0 mmol/L or more, a measured random blood glucose concentration of 11.1 mmol/L or more, or self reported diagnosis of diabetes.
We obtained covariates from the baseline questionnaire, including sociodemographic characteristics (age, sex, education, occupation, household income, and marital status), lifestyle behaviors (alcohol consumption, tobacco smoking, physical activity, and intakes of red meat, fresh fruits, and vegetables), personal health and medical history (hypertension, diabetes, chronic hepatitis or cirrhosis, peptic ulcer, gallstones or cholecystitis, and menopausal status for women only), and information on family members, including biological parents and siblings who had had cancer, heart attack, stroke, or diabetes. The daily level of physical activity was calculated by multiplying the metabolic equivalent tasks (METs) value for a particular type of physical activity by hours spent on that activity per day and summing the MET hours for all activities. Habitual dietary intake in the past year was assessed by a qualitative food frequency questionnaire. A participant was considered as having a family history of a particular disease if they reported at least one first degree relative with the disease.
After completion of the baseline survey in July 2008, about 5% randomly chosen surviving participants in 10 survey sites were resurveyed during August and October of 2008. 14 To test the reproducibility of the frequency of spicy food consumption, we included 1300 participants who completed the same questionnaire twice at an interval of less than 1.5 years (median 1.4 years). Spearman’s coefficient for the correlation between the two questionnaires was 0.71, indicating that spicy food consumption was reported consistently.
In the baseline questionnaire we asked the participants “During the past month, about how often did you eat hot spicy foods?”: never or almost never, only occasionally, 1 or 2 days a week, 3 to 5 days a week, or 6 or 7 days a week. The participants who selected the last three categories were further asked “When you eat spicy foods, what are the main sources of spices usually used?” (multiple choices allowed fresh chilli pepper, dried chilli pepper, chilli sauce, chilli oil, and other or don’t know).
The China Kadoorie Biobank is a prospective cohort study of over 0.5 million adults from 10 geographically diverse areas across China; participants were enrolled between 2004 and 2008 and have been followed up ever since for morbidities and mortality. Further details of the China Kadoorie Biobank study have been described elsewhere. 13 14 Briefly, a total of 512 891 adults aged 30-79 years had valid baseline data—that is, completed questionnaire, physical measurements, and a written informed consent form.
Fig 2 Subgroup analysis of associations between consumption of spicy foods ≥6 days a week and total mortality according to potential baseline risk factors. Hazard ratios for total mortality are for comparison of men and women who ate spicy foods ≥6 days a week with those who ate spicy foods less than once a week. Risk estimates for other categories of spicy food consumption are shown in appendix table 2. Horizontal lines represent 95% confidence intervals
We also analyzed the associations between spicy food consumption and total mortality according to other potential baseline risk factors for death; the inverse associations between spicy food consumption and total mortality were generally similar across subgroups stratified according to age, smoking status, level of physical activity, and body mass index (all P values for interaction >0.05) (fig 2 ⇓ and appendix table 2). Significant differences across stratums were observed for alcohol consumption, with a stronger inverse association among participants who did not consume alcohol than those who did (P=0.033 for interaction).
Fig 1 Subgroup analysis of associations between consumption of spicy foods ≥6 days a week and total and cause specific mortality according to consumption of fresh chilli pepper. Hazard ratios for death from all causes and from specific causes are for comparison of men and women who ate spicy foods ≥6 days a week with those who ate spicy foods less than once a week. Appendix table 1 shows the risk estimates for other categories of spicy food consumption. Horizontal lines represent 95% confidence intervals
We further performed stratified analyses according to whether the participants reported using fresh chilli pepper as their predominant spice. We found that the inverse associations of daily spicy food consumption with death due to cancer, ischemic heart diseases, and diabetes seemed stronger in the fresh chilli group than in the non-fresh chilli group in the whole cohort of women and men, and the results were statistically significant in the fresh chilli group (fig 1 ⇓ and appendix table 1).
In the sensitivity analyses, the associations of spicy food consumption with total and cause specific mortality did not change appreciably with additional adjustment for occupation and household income; or additional adjustment for histories of chronic hepatitis or cirrhosis, peptic ulcer, and gallstone or cholecystitis; or adjustment for a 13 level detailed smoking variable instead of a four level smoking variable; or excluding participants dying during the first two years of follow-up; or excluding participants with prevalent diabetes at baseline; or excluding participants with exclusive use of other spices instead of any types of chilli (data not shown). The associations of spicy food consumption with total and cause specific mortality were consistently observed in participants from both rural and urban areas and for different follow-up durations (<3 or ≥3 years).
After multivariate adjustment, spicy food consumption was inversely associated with the risks of death due to cancer, ischemic heart diseases, and respiratory diseases in the whole cohort (table 2). No statistically significant heterogeneity was observed in the associations between spicy food consumption and cause specific mortality by sex (all P>0.05). Nevertheless, the associations seemed to be less evident in men than in women (table 3). In addition, more frequent consumption of spicy foods in women was also significantly associated with a reduced risk of death due to infections.
During a median follow-up of 7.2 years (interquartile range 1.84 years; total person years 3 500 004), we documented 11 820 deaths among men and 8404 deaths among women. Absolute mortality rates according to spicy food consumption categories were 6.1, 4.4, 4.3, and 5.8 deaths per 1000 person years for participants who ate spicy foods less than once a week and 1 or 2, 3 to 5, and 6 or 7 days a week, respectively. Age adjusted and multivariate adjusted analyses showed a statistically significant inverse association between spicy food consumption and total mortality. In the whole cohort, compared with participants who ate spicy foods less than once a week, the adjusted hazard ratios for death were 0.90 (95% confidence interval 0.84 to 0.96) for those who ate spicy foods 1 or 2 days a week, 0.86 (0.80 to 0.92) for 3 to 5 days a week, and 0.86 (0.82 to 0.90) for 6 or 7 days a week (table 2 ⇓ ). Compared with participants who ate spicy foods less than once a week, those who consumed spicy foods 6 or 7 days a week showed a 14% relative risk reduction in total mortality. The multivariate adjusted hazard ratios for total mortality among men, compared with men who ate spicy foods less than once a week, were 0.90 (0.83 to 0.98) for those who ate spicy food 1 or 2 days a week, 0.90 (0.83 to 0.99) for 3 to 5 days, and 0.90 (0.85 to 0.96) for 6 or 7 days a week; the respective hazard ratios among women were 0.88 (0.79 to 0.98), 0.78 (0.69 to 0.88), and 0.81 (0.75 to 0.87) (table 3 ⇓ ). There was no heterogeneity between men and women in any of the associations (P=0.723).
Table 1 ⇓ presents the age and site adjusted baseline characteristics of the participants according to the categories of spicy food consumption. Compared with participants who consumed spicy foods less frequently (3 to 5 days a week or less), those who consumed spicy foods almost every day were more likely to be rural residents, more likely to smoke tobacco and consume alcohol, and more frequently to consume red meat, vegetables, and fruits. Fresh and dried chilli peppers were the most commonly used types of spices in those who reported consuming spicy foods weekly (table 1).
Discussion
In this large prospective study, we observed an inverse association between consumption of spicy foods and total mortality, after adjusting for potential confounders. Compared with those who ate spicy foods less than once a week, those who consumed spicy foods almost every day had a 14% lower risk of death. Inverse associations were also observed for deaths due to cancer, ischemic heart diseases, and respiratory diseases. The associations were consistent in men and women.
Strengths and limitations of this study The strengths of this study include a large sample size, a prospective cohort design, and careful control for established and potential risk factors for death. This study does have a few limitations. Consumption of spicy foods may be correlated with other dietary habits and lifestyle behaviors. For example, in Chinese cuisine the cooking of chilli pepper and the production of chilli sauce and oil usually requires more oil, and intake of pungent foods may be accompanied by an increased intake of carbohydrate-rich foods such as rice to relieve the burning sensation. However, the lack of detailed dietary information in this study limited our ability to comprehensively adjust for total energy intake and other specific dietary factors. In addition, spicy food consumption may be correlated with socioeconomic status,16 which we partly controlled for in our analyses. Residual confounding by other unmeasured or unknown biological and social factors was still possible, although we carefully adjusted for several established and potential risk factors for death. However, residual confounding by the aforementioned or other confounding factors might have attenuated the inverse associations between spicy food consumption and mortality toward the null. Although chilli pepper was the most commonly used spice in our population, the use of other types of spices usually increases as the use of chilli pepper increases. Thus the health benefits of these spices apart from chilli pepper may also contribute to the observed inverse associations. Reverse causality is another possible explanation for our findings because people with chronic disease might abstain from spicy foods. However, we excluded participants who had cancer, heart disease, or stroke at baseline. Moreover, the results remained largely unchanged when we excluded participants dying during the first two years of follow-up from analyses or additionally adjusted for several major digestive system diseases that might deter people from consuming spicy foods. Although we employed multiple ways to maximize death ascertainment of participants, under-reporting of deaths might have occurred. However, the proportion of participants under-reported on death status would not depend on the levels of spicy food consumption. Considering that specificity of outcome detection is nearly perfect and sensitivity is lower than 100% in both exposure groups, outcome misclassification would produce little bias in estimating hazard ratio.17 The consumption of spicy foods was self reported; therefore, some measurement error is inevitable. The questionnaire on spicy food consumption used in our study has not yet been validated directly; however, previous studies have shown that using similar food frequency questionnaires could produce valid estimates of food consumption in a Chinese population.18 In addition, in a prospective study design, measurement errors may be non-differential and the measure of association is more likely to be biased toward the null. The consumption of spicy foods reported for a short period may not necessarily reflect the long term patterns of consumption. However, repeated collections of dietary information averaged 1.4 years in our cohort and have shown that the reported intakes of dietary factors including spicy foods were highly consistent over time. In addition, information was not available on how spicy foods were prepared and cooked. Such information would have enabled us to perform further analyses on the relation between spicy food consumption and mortality more extensively.
Comparison with other studies and potential mechanism Our study is the first to analyze the association between daily consumption of spicy foods and mortality in a prospective cohort. Our findings are in line with previous evidence showing potential protective effects of spicy foods on human health. Capsaicin is the main active component of chilli pepper. The beneficial roles of capsaicin have been extensively reported in relation to anti-obesity, antioxidant, anti-inflammatory, anticancer, and antihypertensive effects, and in improving glucose homeostasis, largely in experimental or small sized population studies.7 8 9 Additionally, the antimicrobial function of spices, including chilli pepper, has long been recognized,3 19 and such a property may have an important effect on the gut microbiota in humans. In recent years, rapidly emerging evidence has implicated gut microbiota as a novel and important metabolic factor that affects the health of the host,20 and several studies in humans have related abundance, composition, and metabolites of gut microbiota to risk of obesity,21 22 23 diabetes,12 24 liver cirrhosis,11 and cardiovascular disease.10 25 However, how spicy foods and their bioactive ingredients may affect the composition and activity of gut microbiota has yet to be further investigated. In addition, our study suggested a threshold of around 1 or 2 days a week of spicy food consumption, beyond which the risk for mortality did not decrease further. Possible mechanisms might involve the bioaccessibility and bioavailability of bioactive ingredients and nutrients of spicy foods26; but further studies are needed to verify our findings. Our study indicated that spicy food consumption was particularly related to the reduced risk of mortality due to cancer, ischemic heart diseases, and respiratory diseases. Several previous epidemiological studies have suggested protective effects of capsaicin consumption on stomach or gallbladder cancer,7 9 27 although such effects were not consistently observed. The cardiovascular system is rich in capsaicin sensitive sensory nerves, which have an extensive role in regulating cardiovascular function.28 The antioxidant and antiplatelet properties of capsaicin and the important role of capsaicin in regulating energy metabolism may also contribute to its beneficial effects on the cardiovascular system.7 9 28 29 30 31 32 Less well known are the possible mechanisms underlying the potentially beneficial effect of spicy foods on respiratory diseases. However, the anti-obesity, antioxidant, anti-inflammatory, and antihypertensive effects of spicy foods would generally protect all these specific systems. Because the number of deaths from infections was relatively small, our study might not have had enough statistical power to rule out a possible relation between spicy food consumption and infections specific mortality. Compared with non-fresh spicy foods such as dried chilli pepper, chilli sauce, or chilli oil, fresh chilli pepper is richer in bioactive ingredients, including capsaicin, vitamin C, and other nutrients such as vitamin A, K, and B6, and potassium. In our stratified analyses we found that the inverse associations of spicy food consumption with certain cause specific deaths (cancer, ischemic heart disease, and diabetes) seemed to be stronger in those who consumed fresh chilli pepper than those who consumed non-fresh spicy foods. These data suggest that some of the bioactive ingredients are likely to be effective in driving the observed associations. Interestingly, a statistically significant inverse association between the daily consumption of spicy foods and diabetes, which was not observed in the whole cohort, was found in the subgroup that consumed fresh chilli pepper. This was consistent with previous evidence showing that dietary capsaicin may provide beneficial effects on glucose homeostasis.33 However, it remains unclear whether other nutrients abundant in fresh chilli pepper also have roles in lowering the risk of mortality. Intriguingly, we found that the inverse association was stronger in those who did not than did drink alcohol. Alcohol consumption has been related to an increased risk of mortality in some but not all previous studies.34 35 36 Even though moderate alcohol consumption has been related to a reduced risk of certain chronic diseases such as diabetes, moderately high alcohol consumption may increase energy intake37 and has been associated with increased mortality.38 In addition, alcohol intake also affects the metabolism of gut microbiota.39 40 Even though the precise mechanism remains unclear, the interaction between spicy foods and alcohol intake is biologically possible. We acknowledge that disease status might affect both alcohol and spicy food intakes, and we excluded participants with chronic diseases such as cancer, heart disease, or stroke at baseline from our analyses. Further investigations are warranted to validate our findings and explore the mechanisms. ||||| TIME Health For more, visit TIME Health
People who love chili peppers might be eating their way to a longer life, according to a new study published in The BMJ.
“We know something about the beneficial effects of spicy foods basically from animal studies and very small-sized human studies,” says study author Lu Qi, associate professor at the Harvard School of Public Health. Some of those preliminary studies have found that spicy food and their active components—like capsaicin, the compound found in chili peppers—might lower inflammation, improve metabolic status and have a positive effect on gut bacteria and weight, he says.
But human evidence remains scant. So Qi and a team of researchers looked at questionnaire data from about half a million adults all across China who participated in the China Kadoorie Biobank study between 2004-2008. Each person in the study reported their health status, alcohol consumption, spicy food consumption, main source of chili intake (fresh or dried, in a sauce or in an oil) as well as meat and vegetable consumption.
The researchers followed up with them about seven years later. Compared to people who ate spicy foods less than once a week, people who ate them just once or twice a week had a 10% reduced risk of death. Bumping up the spice consumption didn’t make much of a difference; those who ate spicy food 3-7 days a week were at 14% reduced risk of death compared to the most spice-averse group.
Eating chili-rich spicy foods was also linked to a lower risk of death from certain diseases, including cancer, ischemic heart diseases and respiratory diseases, they found. Further analysis revealed that fresh chili had a stronger protective effect against death from those diseases.
More research is needed to make any causal case for the protective effects of chili—this does not prove that the spicy foods were the reason for the health outcomes—but Qi finds this observational research valuable. “It appears that increasing your intake moderately, just to 1-2 or 3-5 times a week, shows very similar protective effect,” he says. “Just increase moderately. That’s maybe enough.”
MORE: 3 Reasons You Should Eat More Spicy Food | – People who like a little heat in their meals just might be doing their longevity a favor. So report researchers this week in the British Medical Journal after studying the health, diets, and alcohol consumption of more than 485,000 people in China. Controlling for many variables, including family medical history, age, education, diabetes, and smoking, they found that those who ate spicy foods—mainly via chili peppers—once or twice a week enjoyed a 10% reduced overall risk for death than those who ate spicy foods less than once a week, reports the New York Times. And that reduction improved to 14% when people ate spicy foods six or seven times a week. "We know something about the beneficial effects of spicy foods basically from animal studies and very small-sized human studies," study author Lu Qi of Harvard tells Time. Some findings focus on active components like capsaicin found in chili peppers that appears to reduce inflammation and improve metabolic status, gut bacteria, and weight, he adds. "It appears that increasing your intake moderately, just to one to two or three to five times a week, shows very similar protective effect. Just increase moderately. That’s maybe enough." Of course, more research is needed to demonstrate actual causation, but for now the link between the consumption of spicy foods and lower risk of death appears strong. (This man says hot sauce saved his life.) |
since the neutrino oscillation was first observed at super - kamiokande ( sk ) @xcite , many experiments have measured the physics parameters of the neutrino oscillation @xcite-@xcite .
some of these experiments observe the survival probability of @xmath6 and @xmath7 which are generated in the atmosphere by the cosmic ray @xcite .
accelerator based long baseline experiments @xcite also measure the @xmath6 survival probability . from the combined results of these experiments @xcite-@xcite ,
the mass - squared difference and the mixing angle are obtained as @xmath19 [ eq : atm_data ] @xmath20 the sign of the mass - squared difference , eq .
( [ eq : mass_atm ] ) , can not be determined from these experiments .
the sk collaboration also reported that the atmospheric neutrinos oscillate into active neutrinos @xcite .
the combined results of the solar neutrino observations @xcite , which measure the survival probability of @xmath21 from the sun , and the kamland experiment @xcite , which measure the @xmath22 flux from the reactors at distances of a few 100 km , find @xmath23 [ eq : sun_data ] @xmath20 where the sign of mass - squared difference has been determined by the matter effect inside the sun @xcite .
the sno experiment determined that @xmath21 from the sun changes into active neutrinos @xcite . for the reactor experiments , which measure the survival probability of @xmath22 from the reactor at distances of @xmath24 km @xcite , the chooz experiment observed no signal , giving @xmath25 [ eq : rct_data ] @xmath20 at the 90% confidence level @xcite .
more recently , the t2k collaboration reported several @xmath26 appearance candidate events giving @xmath27 for @xmath28 and @xmath29 with the normal ( inverted ) hierarchy at the 90% confidence level @xcite .
the minos collaboration reported @xmath30 also for @xmath28 and @xmath29 with the normal ( inverted ) hierarchy @xcite .
the double chooz collaboration , which is one of the new reactor experiments , found hints of reactor electron anti - neutrino disappearance consistent with neutrino oscillation and reported @xmath31 from analyzing both the rate of the prompt positrons and their energy spectrum @xcite . recently
another new reactor experiment , the dayabay experiment @xcite , announced that they have measured the neutrino mixing angle as @xmath32 which is more than @xmath33 away from zero . the reno collaboration , which also measure the reactor @xmath22 survival probability , shows the evidence of the non - zero mixing angle ; @xmath34 from a rate - only analysis , which is @xmath35 away from zero .
since the miniboone experiment @xcite did not confirm the lsnd observation of rapid @xmath36 oscillation @xcite , there is no clear indication of experimental data which suggests more than three neutrinos .
therefore the @xmath26 appearance analysis of t2k @xcite and minos@xcite presented above assume the 3 neutrino model , with the @xmath37 flavor mixing , the mns ( maki - nakagawa - sakata ) matrix @xcite @xmath38 relating the weak interaction eigenstates @xmath39 and the mass eigenstate @xmath40 with the mass @xmath41 ( @xmath42 ) .
the mass - squared differences that dictate the neutrino oscillation phase are then identified as @xmath43 where only the magnitude of the larger mass - squared difference , @xmath44 is determined in eq .
( [ eq : mass_atm ] ) .
the @xmath45 case is called normal , while @xmath46 case is called inverted neutrino mass hierarchy . with a good approximation @xcite
, the three independent mixing angles of the mns matrix can be related to the oscillation amplitudes in eqs .
( [ eq : mixing_atm ] ) , ( [ eq : mixing_sun ] ) , and @xmath47 in eqs .
( [ eq : mixing_rct ] ) , ( [ eq : t2k_s13 ] ) to ( [ eq : dayabay_s13 ] ) , with the mns matrix elements @xmath48 : @xmath49 [ eq : mns_exp ] @xmath20 in the last equations , the defining region of the three mixing angles @xmath50 can be chosen as @xmath51 @xcite , which is consistent with the convention of non - negative @xmath52 and @xmath53 @xcite .
the argument of @xmath54 gives the cp phase of the mns matrix , @xmath55 even after @xmath56 , the smallest of the three mixing angles , is measured by the accelerator based long baseline experiments @xcite and the reactor experiments @xcite , three unknowns remain in the 3 neutrino model , which are the sign of the larger mass - squared differences , normal ( @xmath57 ) or inverted ( @xmath58 ) , the leptonic cp phase ( @xmath10 ) , and the sign of @xmath59 if its magnitude differs from zero significantly .
the main purpose of the next generation neutrino oscillation experiments is to determine these three unknown parameters of the three neutrino model .
the accelerator based long baseline neutrino oscillation experiment with two - detectors for one - beam , such as tokai - to - kamioka - and - korea ( t2kk ) experiment @xcite-@xcite , is one of the promising experiments for measuring all the three unknowns .
when one measures the neutrino energy ( @xmath60 ) and the magnitude of the @xmath21 appearance probability at significantly different baseline lengths , the degeneracy between the sign of the larger mass - squared difference and the cp phase can be resolved @xcite-@xcite , since they affect the magnitude of the @xmath21 appearance probability and the neutrino energy at the first oscillation maximum differently at the two baseline lengths .
once the mass hierarchy and the cp phase are determined , the sign of @xmath59 can be determined @xcite since the @xmath26 oscillation probability is proportional to @xmath61 . in the previous works @xcite-@xcite , physics impacts of the t2kk experiment
have been studied systematically , and the following observations have been made : if a 100 kton water detector is placed in korea at @xmath62 km observing the @xmath13 off - axis beam ( oab ) during the t2k exposure time of @xmath63 pot ( protons on target ) , the mass hierarchy can be resolved at 3@xmath8 level for @xmath64 when the hierarchy is normal ( inverted ) , and the cp phase can be constrained uniquely , by measuring the ccqe ( charged - current quasi elastic ) events @xcite .
the sign of @xmath59 can also be determined for @xmath65 with @xmath66 level , if @xmath67 for the normal hierarchy @xcite .
when we take into account the smearing of reconstructed neutrino energy due to finite detector resolution and the fermi motion of target nucleons , resonance production , and the neutral current ( nc ) @xmath68 production background to the @xmath21 appearance signal , it is found that the mass hierarchy pattern can still be determined at @xmath66 level for @xmath69 when the hierarchy is normal ( inverted ) , but the cp phase can no longer be established at @xmath66 level with @xmath63 pot @xmath6 exposure @xcite . in ref.@xcite ,
matter distribution profile along the t2k and tokai - to - korea baselines have been studied , and merits of splitting the total exposure time into half @xmath6 and half @xmath7 beam have been reported .
studies on the impacts of the neutrino energy smearing and the nc @xmath68 background for the @xmath36 oscillation measurements are in progress @xcite .
oki island is placed between japan and korea along the t2k baseline and inside japanese territory .
the distance from j - parc to oki island is about @xmath70 km which is about two times longer than that of the t2k experiment ( @xmath0 km ) . in fig .
[ fig : t2oki1 ] , we show the surface map of the t2k , t2ko ( tokai - to - kamioka - and - oki ) , and t2kk experiments , in which the red lines denote the baselines for each experiment and the yellow blobs show the center of the neutrino beam from j - parc at the sea level , when the off - axis angle at sk is @xmath71 , @xmath72 , and @xmath73 .
the authors of ref.@xcite consider the physics performance of a 100 kton liquid argon time projection chamber placed at oki island . in ref.@xcite
, the authors studied the oki island site from the geological , geographic and infrastructure points of view for the possibility to construct a large detector .
they conclude that oki island is one of the good candidate sites for a large detector . in this paper , we study the physics potential of a 100 kton water detector placed in oki island instead of korea during the t2k experimental period , by using exactly the same setting assumed for the t2kk experiment in ref.@xcite , except for the location of the detector .
this allows us to compare the physics capability of the two proposals on the same footing .
since we do assume in this analysis that the @xmath74 ccqe events can be distinguished from the background , our results should equally be applied for a more advanced liquid argon detector @xcite .
this article is organized as follows . in the next section ,
we briefly review neutrino oscillation in the matter and give useful approximation formula for @xmath74 and @xmath75 oscillation probabilities . in section [ sec : far ]
, we show the matter profile between j - parc and oki island by using recent seismological measurements and give relations between the off - axis angle observable at oki and that at sk .
the expected numbers of @xmath74 @xmath76 ccqe events at the far ( oki ) and the near ( sk ) detectors are shown for typical parameters in section [ sec : event ] . in section [ sec : chi ] , we present the @xmath77 function with which we estimate the statistical sensitivity of the t2ko and t2kk experiments on the mass hierarchy and the cp phase . in section
[ sec : mass ] , we show the results on the mass hierarchy determination of the t2ko experiment and compare it with t2kk , and also with 2kn where the 100 kton detector is placed in the kamioka site making the total fiducial volume 122 kton at @xmath0 km . in section [ sec : cp ] , we show the cp phase sensitivity of t2ko , t2kk , and 2kn experiments .
we summarize our findings in the last section .
in long baseline neutrino oscillation experiments , neutrinos from the accelerator interact coherently with electrons and nucleons by charged and neutral current interactions .
these coherent interactions make an additional potential in the effective hamiltonian @xcite . because the potential from the neutral current interactions are flavor - blind , it does not affect the neutrino oscillation probability in the three neutrino model . on the other hand , the charged - current interactions contribute only to the effective potential of @xmath21 and @xmath22 .
the neutrino oscillation probabilities hence depend on the matter density profile along the baseline .
detailed studies on the matter distribution dependence of the oscillation probabilities for the t2k and t2kk experiments are found in ref .
@xcite . in this exploratory analysis
, we compare the physics capability of the t2ko , t2kk , and t2k experiments by using the average matter density along the baselines which is found to approximate the matter effects rather accurately @xcite .
the hamiltonian of a neutrino propagating in the matter is then expressed as @xmath78\ , , \label{eq : hamiltonian1}\\ & = & \dfrac{1}{2e } \tilde{u}^ { } \left ( \begin{array}{ccc } \lambda_1 & & \\ & \lambda_2 & \\ & & \lambda_3 \end{array } \right ) \tilde{u}^\dagger\ , , \label{eq : hamiltonian2}\end{aligned}\ ] ] [ eq : hamiltonians ] @xmath20 on the flavor space @xmath79 , with @xmath80 , where @xmath81 gives the matter effect with the electron number density @xmath82 , which is approximated by the average matter density @xmath83 ( g/@xmath84 ) along the baseline . by using the solution of eq .
( [ eq : hamiltonian2 ] ) , the oscillation probability that an initial flavor eigenstate @xmath85 is observed as a flavor eigenstate @xmath86 after traveling a distance @xmath87 along the baseline is @xmath88 [ eq : ppps ] @xmath20 where @xmath89 all our numerical results are based on eq .
( [ eq : ppps ] ) . however , we find the following analytic approximations @xcite useful for understanding the reason why and how the one - beam two - detectors long baseline experiments such as t2kk @xcite-@xcite and t2ko , with a far detector in oki island , can determine the neutrino mass hierarchy and the cp phase simultaneously .
they are obtained by expanding the oscillation probabilities in terms of the three small parameters ; the matter effects , which is small at energies below a few gev around the earth crust for @xmath90 g/@xmath84 and @xmath91 km , the oscillation phase @xmath92 , which is also small ( @xmath93 ) near the first oscillation maximum , @xmath94 , and the mixing factor @xmath95 , eq .
( [ eq : def_srct ] ) , which is about @xmath96 from the recent reactor measurements eqs .
( [ eq : dayabay_s13 ] ) and ( [ eq : reno_s13 ] ) .
the @xmath6 survival probability can then be approximated as @xmath97 around the first maximum of the main oscillation phase @xmath98 with [ eq : abmu ] @xmath99 we find that the above formula reproduce the survival probability with 1% accuracy throughout the parameter range explored in this analysis , which covers all the three neutrino model parameters in the @xmath66 allowed range of the present measurements eqs .
( [ eq : atm_data])-([eq : reno_s13 ] ) , for the neutrino energies 400 mev @xmath100 4 gev ( for @xmath6 , @xmath7 ) , and for the baseline lengths @xmath101 km @xmath102 1200 km , except where the probability is very small , ( @xmath103 ) @xcite .
the matter effects are proportional to the term @xmath104 and it appears with the opposite sign both in the amplitude correction term @xmath105 eq .
( [ eq : amu ] ) where @xmath106 for the normal while @xmath107 for the inverted hierarchy , and also in the phase shift in eq .
( [ eq : pmm ] ) , where @xmath108 for the normal , @xmath109 for the inverted hierarchy around the oscillation maximum @xmath110 . nevertheless , the effect is too small to be observed in the near future because the term @xmath111 is bounded as @xmath112 at @xmath113 c.l . from eq .
( [ eq : mixing_atm ] ) , and because both @xmath105 and @xmath114 are proportional to the product of the two small parameters , the matter effect term of @xmath115 and @xmath116 .
the coefficient of @xmath117 in @xmath114 is also small , only @xmath118 of the main oscillation phase @xmath119 .
in other words , the @xmath6 survival probability is very insensitive to the unknown parameters of the three neutrino model , and hence can be used to measure @xmath120 and @xmath121 accurately . under the same conditions that give eq .
( [ eq : pmm ] ) for the @xmath6 survival probability , the @xmath21 appearance probability can be approximated as @xcite @xmath122 where we retain both linear and quadratic terms of @xmath123 and @xmath124 .
the analytic expressions for the correction terms @xmath125 , @xmath126 and @xmath127 are found in ref.@xcite . for our semi - quantitative discussion below
, the following numerical estimates @xcite for @xmath128 and @xmath129 suffice : [ eq : abeapprox ] @xmath131 the term @xmath127 is relevant only when the @xmath26 oscillation probability is very small @xcite .
the first term in @xmath125 in eq .
( [ eq : aeaprox ] ) is sensitive not only to the matter effect but also to the mass hierarchy pattern , since @xmath132 for the normal while @xmath133 for the inverted hierarchy around the oscillation maximum . for the normal ( inverted ) hierarchy , the magnitude of the @xmath26 transition probability
is enhanced ( suppressed ) by about @xmath134 at kamioka , @xmath135 at oki island , and @xmath136 at @xmath137 km in korea , around the first oscillation maximum , @xmath138 .
when @xmath139 is fixed at @xmath140 , the difference between the two hierarchy cases grows with @xmath87 , because the matter effect grows with @xmath60 . within the allowed range of the model parameters , the difference of the @xmath125 between sk and a far detector at oki or korea becomes @xmath141 [ eq : ae_diffs ] @xmath20 where the upper sign corresponds to the normal , and the lower sign for the inverted hierarchy .
the hierarchy pattern can hence be determined by comparing @xmath142 near the oscillation maximum @xmath143 at two vastly different baseline lengths @xcite-@xcite , _ independently _ of the sign and magnitude of @xmath144 . in eq .
( [ eq : beaprox ] ) , it is also found that the first term in @xmath126 , which shifts the oscillation phase from @xmath119 to @xmath145 , is also sensitive to the mass hierarchy pattern . as in the case for @xmath125 ,
the difference in @xmath126 between sk and a far detectors is found to be @xmath146 [ eq : be_diffs ] @xmath20 where the upper sign is for the normal , and the lower sign for the inverted hierarchy .
this implies that the mass hierarchy pattern can also be discriminated by measuring the neutrino energy of the first oscillation maximum at two different baseline lengths . as in the case of the oscillation amplitude above
, this determination can be made independent of the unknown @xmath117 terms since they cancel in the differences , eq .
( [ eq : be_diffs ] ) .
once the sign of @xmath147 is fixed by the terms linear in @xmath83 , the terms linear in @xmath123 , which appear as those proportional to @xmath148 in eq .
( [ eq : abeapprox ] ) , allow us to constrain @xmath144 via the amplitude @xmath125 , and @xmath117 via the phase shift @xmath126 .
therefore , @xmath10 can be measured uniquely once the mass hierarchy pattern is determined . from the above discussions , we understand qualitatively why the mass hierarchy as well as both @xmath144 and @xmath117 can be determined uniquely by observing the @xmath26 oscillation probability around the first oscillation maximum at two vastly different baseline lengths .
therefore , in order to take advantage of this very efficient mechanism to determine all the main unknowns of the three neutrino model , one should arrange for high neutrino flux both at near and far detectors around the first oscillation maximum which appears at the same energy - to - baseline - length ratio , @xmath149 for @xmath150ev@xmath151 ; eq .
( [ eq : mass_atm ] ) .
this observation led to the t2kk proposal of choosing the @xmath73 off - axis beam ( @xmath152gev ) at sk and @xmath153 off - axis beam ( @xmath154gev ) at @xmath137 km @xcite .
since the baseline length of @xmath155 km to oki island is about a factor of two longer than @xmath156 km for t2k , we may also expect that a beam with smaller off - axis angle at oki island will enhance its physics capability ; see , however , discussions in section [ sec : mass ] .
the oscillation probabilities for the anti - neutrino , @xmath157 , are obtained from the expressions for @xmath158 by reversing the sign of the matter effect term , ( @xmath159 ) , and that of @xmath10 , ( @xmath160 ) .
the differences in the shift terms @xmath125 and @xmath126 for @xmath26 and @xmath161 and @xmath162 for @xmath36 oscillation probabilities are , respectively , @xmath163\ , , \label{eq : diff_be}\end{aligned}\ ] ] [ eq : diff_ae_and_be ] @xmath20 where the upper sign should be taken for the normal and the lower sign for the inverted hierarchy . from eq .
( [ eq : diff_ae ] ) , the difference of the amplitude between @xmath21 and @xmath22 appearance probability grows with the baseline length with the opposite sign for the normal and inverted hierarchies .
the dependence on @xmath144 is also strong since @xmath125 and @xmath161 changes in the opposite direction when we vary @xmath144 .
the phase - shift term @xmath126 and @xmath162 also change sign in the opposite direction for the normal and inverted hierarchies , whose sign is independent of @xmath117 because of the smallness of the @xmath117 dependence in eq .
( [ eq : diff_be ] ) . by the same token
, the use of both @xmath6 and @xmath7 beams does not improve significantly the measurement of @xmath117 .
because these sign changes occur independently of the @xmath87-dependence of the oscillation probabilities , the physics potential of the t2ko experiment will be improved by dividing the total exposure time to neutrino and anti - neutrino beams just as in t2kk @xcite .
it is worth noting here that all the formalism presented in this section should be useful for studying physics potential of t2k plus nova @xcite , whose baseline length of @xmath164 km lies between those of tokai to oki island ( @xmath165 km ) and to korea ( @xmath166 km ) .
in this section , we study the matter profile along the baselines between j - parc and kamioka , oki island , and korea by referring to recent seismological measurements @xcite- @xcite .
we also show the relation between the off - axis angles at sk and oki island , and the beam profiles for the relevant off - axis angles @xcite . because oki island is placed just at the middle point between sk and the east shore of korea along the t2k beam , as shown in fig .
[ fig : t2oki1 ] , the cross section view of the t2k , t2ko , and t2kk experiments along the baselines can be shown on one frame as in fig .
[ fig : xsec - t2oki ] .
the horizontal axis of fig . [ fig : xsec - t2oki ] gives the distance from j - parc along the arc of the earth surface and the vertical axis denotes the depth below the sea level .
three curves show the baselines from the j - parc to sk ( @xmath0 km ) , oki island ( @xmath70 km ) and to the korean east shore at @xmath12 km .
the numbers in the white boxes are the average matter density of the layer in units of g/@xmath84 .
@xcite-@xcite . ]
if we assume that the matter density in each layer of the earth crust as shown in fig . [ fig : xsec - t2oki ] has the value equals to the quoted average , we can estimate the average matter density @xmath83 along the three baselines : @xmath167 [ eq : matter ] @xmath20 the error of these average density can be estimated from the uncertainty of the matter density in each region and the location of the boundary of each layer .
they are measured by using the velocity of the seismic wave in most geophysical researches . from the uncertainty in the correlation between the matter density and the measured @xmath168-wave sound velocity @xcite
, we adopt @xmath169 overall error for the matter density .
small fluctuation in the matter density in each layer of the earth crust does not affect the neutrino oscillation probabilities significantly , because the contribution from the higher fourier modes of the matter density distribution is strongly suppressed @xcite .
the locations of the boundaries are measured rather accurately from the reflection point of the seismic wave . from fig .
[ fig : xsec - t2oki ] , we find that the neutrino beam for the tokai - to - oki baseline goes through the upper crust layer with @xmath170g/@xmath84 , except when it crosses fossa magna filled with sediment .
the uncertainty of the boundary depth between the sediment layer and the upper crust is only a few hundred meters .
the error from the uncertainty of the boundary depth can hence be safely neglected for the t2ko experiment .
the traveling distance in the mantle and the crust depends on the depth of the boundary between the lower crust and the upper mantle for the t2kk experiment .
the average matter density is sensitive to the boundary location for the baseline of @xmath171 km , because the baseline almost touches the mantle as can be seen from fig .
[ fig : xsec - t2oki ] .
the resulting uncertainty has been estimated and is found to be significantly smaller than the @xmath169 overall uncertainty @xcite .
we therefore use the average matter density along each baseline given in eq .
( [ eq : matter ] ) to estimate the oscillation probability and assign its overall uncertainty of @xmath169 in this study .
km , 1100 km , and 1200 km ) .
the horizontal axis gives the off - axis angle at sk and the vertical axis is that at the far detector locations .
the purple line shows the off - axis angle at oki island .
the red , blue , and black lines are the smallest off - axis angle at @xmath12 km , 1100 km and 1200 km , respectively .
the points corresponding to the purple circles and black squares are used in our numerical analysis . ]
figure [ fig : relation ] shows the relation among the off - axis angles of the neutrino beam from j - parc observable at sk , oki , and a far detector in korea ( @xmath12 km , 1100 km , and 1200 km ) . the horizontal axis gives the off - axis angle at sk and the vertical axis gives the corresponding off - axis angles at far detector locations .
the purple line shows the off - axis angle at oki island , which grows as that at sk is increased , because both sk and oki island is located in the east ( upper ) side of the beam center of the t2k neutrino beam ; see fig .
[ fig : t2oki1 ] .
the red , blue , and black lines are the smallest off - axis angle observable in korea at @xmath12 km , 1100 km , and 1200 km , respectively .
in contrast to the oki island case , the off - axis angle at korea decreases as that at sk grows , because korea is in the west ( lower ) side of the beam center , also as shown in fig .
[ fig : t2oki1 ] .
the points corresponding to the purple circles and black squares in the figure are used in our numerical analysis in the following sections . in fig .
[ fig : profile ] , the beam profiles of the three off - axis beams ( oab ) with @xmath2 , @xmath72 , and @xmath1 off - axis angles at sk are shown at sk , oki island ( three purple circles in fig .
[ fig : relation ] ) and at @xmath12 km in korea ( three black squares in fig .
[ fig : relation ] ) , together with the @xmath26 and @xmath36 oscillation probabilities as functions of the neutrino energy , @xmath60 in units of gev .
the left column panels are for the @xmath6 focusing beam and the right column ones are for the @xmath7 focusing beam .
the upper three rows , ( a1)-(a3 ) and ( b1)-(b3 ) , display the beam flux for the @xmath6 and @xmath7 focusing beam , respectively , at @xmath172 km in units of @xmath173/cm@xmath151/@xmath175pot ( protons on target ) .
the first row , ( a1 ) and ( b1 ) , gives the beam profile observable at each far detector for the @xmath2 off - axis beam ( oab ) at the sk ( red solid line ) , which gives the @xmath4 oab at oki island ( green dashed line ) , and the @xmath176 oab for a far detector in korea at @xmath12 km ( blue dotted line ) .
the second row , ( a2 ) and ( b2 ) , is for the @xmath72 oab at sk , which gives the @xmath177 oab at oki island , and the @xmath178 oab at @xmath12 km .
the case for the @xmath1 oab at sk , which gives the @xmath3 oab at oki island and the @xmath13 oab at @xmath12 km , is shown in the third row .
it is clearly seen that all fluxes at oki and korea are harder than those at sk .
the hardest flux with @xmath179 gev is found for the @xmath2 at sk beam at oki , and for the @xmath1 at sk beam in korea .
the @xmath72 at sk beam gives almost the same flux shape of @xmath180 oab at oki and at the @xmath12 km location in korea , as shown in fig .
[ fig : t2oki1 ] .
this may call upon the possibility of locating detectors both in oki and in korea , where both detectors observe exactly the same oab around the off - axis angle of @xmath178 . focusing beam and
the right ones are for the @xmath7 focusing beam .
the upper 6 panels , ( a1)-(a3 ) and ( b1)-(b3 ) , show the beam fluxes at @xmath172 km and the bottom 4 panels , ( p1)-(p4 ) , show the @xmath26 ( @xmath181 ) oscillation probability with the input parameters of eqs .
( [ eq : matter ] ) and ( [ eq : input ] ) for @xmath182 and @xmath29 .
the first row , ( a1 ) and ( b1 ) gives the beam profile at each far detector for the @xmath2 off - axis beam ( oab ) at sk , the second row , ( a2 ) and ( b2 ) is for the @xmath72 oab at sk , and the third row , ( a3 ) and ( b3 ) is for the @xmath1 oab at sk .
the fourth row , ( p1 ) and ( p3 ) , shows the @xmath26 and @xmath36 oscillation probability for the normal hierarchy , respectively , and the bottom row , ( p2 ) and ( p4 ) , is for the inverted hierarchy .
, title="fig : " ] focusing beam and the right ones are for the @xmath7 focusing beam .
the upper 6 panels , ( a1)-(a3 ) and ( b1)-(b3 ) , show the beam fluxes at @xmath172 km and the bottom 4 panels , ( p1)-(p4 ) , show the @xmath26 ( @xmath181 ) oscillation probability with the input parameters of eqs .
( [ eq : matter ] ) and ( [ eq : input ] ) for @xmath182 and @xmath29 .
the first row , ( a1 ) and ( b1 ) gives the beam profile at each far detector for the @xmath2 off - axis beam ( oab ) at sk , the second row , ( a2 ) and ( b2 ) is for the @xmath72 oab at sk , and the third row , ( a3 ) and ( b3 ) is for the @xmath1 oab at sk .
the fourth row , ( p1 ) and ( p3 ) , shows the @xmath26 and @xmath36 oscillation probability for the normal hierarchy , respectively , and the bottom row , ( p2 ) and ( p4 ) , is for the inverted hierarchy .
, title="fig : " ] the lower two rows in fig .
[ fig : profile ] show the @xmath26 ( @xmath36 ) oscillation probability in the left ( right ) column , for the normal hierarchy , ( p1 ) and ( p3 ) , and for the inverted hierarchy , ( p2 ) and ( p4 ) .
the oscillation probabilities are calculated for the average matter densities of eq .
( [ eq : matter ] ) , and the three - neutrino - model parameters : @xmath183 [ eq : input ] @xmath131 with @xmath184 [ eq : input_rct ] the plus ( minus ) sign in eq .
( [ eq : input_dm13 ] ) is taken for the normal ( inverted ) hierarchy , whose predictions are shown in the fourth ( bottom ) row of fig .
[ fig : profile ] .
the red solid line in these panels is the oscillation probability at the sk , the green dashed line is for oki island , and the blue dotted line is for a far detector in korea , at @xmath12 km . from the four plots ( p1)@xmath185(p4 ) in the bottom
two rows in fig .
[ fig : profile ] , we find that the first oscillation peak at sk appears at @xmath60 around @xmath186 gev for all the four cases , @xmath6 vs @xmath7 and for both hierarchies . since the oab peaks at around @xmath187 , 0.6 , and 0.5 gev for @xmath2 , @xmath72 , and @xmath1 , respectively , as shown by the red solid curves in the first three rows of fig . [
fig : profile ] , all the oab at sk between @xmath2 and @xmath1 can observe @xmath26 and @xmath36 oscillations with good efficiency . on the other hand ,
the oscillation probabilities at oki island are high at @xmath60 around @xmath188 gev from the green dashed curves in the bottom two rows , where the flux is slightly small for the @xmath1 oab at sk , as shown also by green dashed curves in the third row . finally , at @xmath12 km , the @xmath26 and @xmath189 oscillation probabilities are large at around @xmath190 gev , and hence the oab with @xmath1 at sk is most favorable @xcite-@xcite .
we will confirm the above observations for the whole region of the three neutrino model parameter space in the following sections .
in this section , we explain how we estimate event numbers at each far detector . in order to compare the physics capability of the t2ko experiment and that of t2kk experiment with a far detector at various baseline lengths and oab s
, we adopt the same conditions as those in refs .
@xcite : all the detectors at kamioka , oki island , and korea are assumed to have excellent detection and kinematical reconstruction capabilities for @xmath6 and @xmath21 charged current quasi - elastic ( ccqe ) events within the fiducial volumes of the 22.5 kton at kamioka ( sk ) and 100 kton at oki island or in korea .
we use the neutrino fluxes of j - parc beam at various off - axis angles @xcite and the ccqe cross sections off water target @xcite to compute event numbers as functions of ( reconstructed ) neutrino energy with the bin width of @xmath191 mev at @xmath192 mev .
the energy bin width of 200 mev is chosen to take account of kinematical reconstruction errors due to fermi motion , resonance production and detector resolutions @xcite .
we take account of background from secondary beams , such as @xmath21 , @xmath22 and @xmath7 fluxes for the @xmath6 focusing beam , but we do not consider other backgrounds including the single @xmath68 production from the neutral current ( nc ) events @xcite .
in other words , the results of our studies show what a perfect detector of a given fiducial volume can achieve with neutrino beams from j - parc when it is placed along the t2k beam line .
reconstruction efficiency and errors as well as the background rejection capabilities depend on specific detector designs and their studies are beyond the scope of this paper .
the number of @xmath85 ccqe events from the @xmath86 flux in the @xmath6-focusing beam in the @xmath193-th energy bin , @xmath194 , at each site are calculated as @xmath195 where the suffix `` d '' denotes the place of the far detector ( d = sk , oki , kr ) , @xmath196 is neutrino or anti - neutrino flavor @xmath197 , @xmath198 is the fiducial mass of each detector ( @xmath199 kton and @xmath200 kton ) , @xmath201 is the avogadro number , @xmath202 is the @xmath86 flux from j - parc @xcite which scales as @xmath203 , @xmath204 is the neutrino or anti - neutrino oscillation probability calculated by eq .
( [ eq : ppps ] ) with the average matter density of eq .
( [ eq : matter ] ) , and @xmath205 is the ccqe cross sections per nucleon in water for each flavor type @xcite . we also define the event number for @xmath7 focusing beam as @xmath206 where @xmath207 gives the @xmath208 flux in the @xmath7 focusing beam @xcite .
because we only consider the contribution from the secondary neutrino fluxes of the primary beam as the background in this analysis , each @xmath209- and @xmath210-like event numbers in the @xmath193-th bin are calculated as @xmath211 for @xmath212 at each far detector `` d '' ( d = sk , oki , kr ) .
we also define the event numbers with @xmath7 focusing beam as @xmath213 for @xmath212 at each far detector .
[ [ sk ] ] sk ~~ -like ccqe events for @xmath60 ( @xmath214 ) @xmath215 gev at sk ( 22.5kton ) with @xmath1 off - axis angle and @xmath5pot exposure : ( a1 ) and ( a2 ) are for @xmath6 focusing beam , and ( b1 ) and ( b2 ) are for @xmath7 focusing beam ; whereas ( a1 ) and ( b1 ) are for the normal hierarchy , and ( a2 ) and ( b2 ) are for the inverted hierarchy .
the results are for @xmath182 , @xmath29 , and @xmath216 g/@xmath84 and the other input parameters of eq .
( [ eq : input ] ) .
the red solid line in each panel denotes the total event numbers , the purple dotted line shows the @xmath217 contribution in ( a1 ) and ( a2 ) , @xmath218 in ( b1 ) and ( b2 ) , the blue short dashed line gives the sum of the contributions from @xmath36 and @xmath217 in ( a1 ) and ( a2 ) , that of @xmath26 and @xmath218 in ( b1 ) and ( b2 ) , and the green dashed line shows the total background contribution from the secondary beams .
, title="fig : " ] -like ccqe events for @xmath60 ( @xmath214 ) @xmath215 gev at sk ( 22.5kton ) with @xmath1 off - axis angle and @xmath5pot exposure : ( a1 ) and ( a2 ) are for @xmath6 focusing beam , and ( b1 ) and ( b2 ) are for @xmath7 focusing beam ; whereas ( a1 ) and ( b1 ) are for the normal hierarchy , and ( a2 ) and ( b2 ) are for the inverted hierarchy .
the results are for @xmath182 , @xmath29 , and @xmath216 g/@xmath84 and the other input parameters of eq .
( [ eq : input ] ) .
the red solid line in each panel denotes the total event numbers , the purple dotted line shows the @xmath217 contribution in ( a1 ) and ( a2 ) , @xmath218 in ( b1 ) and ( b2 ) , the blue short dashed line gives the sum of the contributions from @xmath36 and @xmath217 in ( a1 ) and ( a2 ) , that of @xmath26 and @xmath218 in ( b1 ) and ( b2 ) , and the green dashed line shows the total background contribution from the secondary beams .
, title="fig : " ] -like ccqe events for @xmath60 ( @xmath214 ) @xmath215 gev at sk ( 22.5kton ) with @xmath1 off - axis angle and @xmath5pot exposure : ( a1 ) and ( a2 ) are for @xmath6 focusing beam , and ( b1 ) and ( b2 ) are for @xmath7 focusing beam ; whereas ( a1 ) and ( b1 ) are for the normal hierarchy , and ( a2 ) and ( b2 ) are for the inverted hierarchy .
the results are for @xmath182 , @xmath29 , and @xmath216 g/@xmath84 and the other input parameters of eq .
( [ eq : input ] ) .
the red solid line in each panel denotes the total event numbers , the purple dotted line shows the @xmath217 contribution in ( a1 ) and ( a2 ) , @xmath218 in ( b1 ) and ( b2 ) , the blue short dashed line gives the sum of the contributions from @xmath36 and @xmath217 in ( a1 ) and ( a2 ) , that of @xmath26 and @xmath218 in ( b1 ) and ( b2 ) , and the green dashed line shows the total background contribution from the secondary beams .
, title="fig : " ] -like ccqe events for @xmath60 ( @xmath214 ) @xmath215 gev at sk ( 22.5kton ) with @xmath1 off - axis angle and @xmath5pot exposure : ( a1 ) and ( a2 ) are for @xmath6 focusing beam , and ( b1 ) and ( b2 ) are for @xmath7 focusing beam ; whereas ( a1 ) and ( b1 ) are for the normal hierarchy , and ( a2 ) and ( b2 ) are for the inverted hierarchy .
the results are for @xmath182 , @xmath29 , and @xmath216 g/@xmath84 and the other input parameters of eq .
( [ eq : input ] ) .
the red solid line in each panel denotes the total event numbers , the purple dotted line shows the @xmath217 contribution in ( a1 ) and ( a2 ) , @xmath218 in ( b1 ) and ( b2 ) , the blue short dashed line gives the sum of the contributions from @xmath36 and @xmath217 in ( a1 ) and ( a2 ) , that of @xmath26 and @xmath218 in ( b1 ) and ( b2 ) , and the green dashed line shows the total background contribution from the secondary beams .
, title="fig : " ] the typical event numbers of the @xmath209-like ccqe events for @xmath60 ( @xmath214 ) @xmath215 gev at sk ( @xmath219 kton ) with the @xmath1 oab and @xmath5 pot exposure is shown in fig .
[ fig : t2k ] : ( a1 ) and ( a2 ) are for the @xmath6 focusing , and ( b1 ) and ( b2 ) are for the @xmath7 focusing beam ; ( a1 ) and ( b1 ) are for the normal , and ( a2 ) and ( b2 ) are for the inverted hierarchy .
these results are for @xmath182 , @xmath29 and @xmath220g/@xmath84 the other input parameters of eq .
( [ eq : input ] ) . in each panel
, the red solid line denotes the total event number , which is the sum of the signal events , @xmath26 for ( a1 ) and ( a2 ) , or @xmath36 for ( b1 ) and ( b2 ) , and the total background from the secondary beams shown by the green dashed line .
the purple dotted line shows the @xmath217 contribution in ( a1 ) and ( a2 ) , @xmath221 in ( b1 ) and ( b2 ) .
the blue short dashed line gives the sum of the contributions from @xmath222 and @xmath223 in ( a1 ) and ( a2 ) , and those from @xmath224 and @xmath225 in ( b1 ) and ( b2 ) . in fig .
[ fig : t2k ] , both the signal ( red solid minus green dash ) and the total ( red solid ) number of events peak in the first bin ( 400 mev @xmath100 600 mev ) , because both the @xmath1 oab fluxes and the oscillation probabilities are largest in the region ; see fig . [
fig : profile ] , ( a3 ) , ( p1 ) , and ( p2 ) for @xmath26 , ( b3 ) , ( p3 ) , and ( p4 ) for @xmath36 . the background levels are higher for the @xmath36 oscillation experiments than the @xmath26 case for both hierarchies .
this is partly because of the higher level of the secondary beam fluxes in the @xmath7 focusing beam @xcite , and partly because the ccqe cross sections are larger for @xmath226 than the @xmath227 ( @xmath228 ) @xcite . since the ratio of the @xmath36 to the @xmath229 event numbers is significantly larger for the inverted hierarchy than that for the normal hierarchy case in fig .
[ fig : t2k ] , one may be tempted to conclude that the neutrino mass hierarchy can be determined by using both @xmath6 and @xmath7 focusing beams at t2k .
this is not the case since the same trend can be expected for @xmath230 , as can be seen clearly from eq .
( [ eq : diff_ae ] ) . , but for tokai - to - oki island ( @xmath70 km ) , where the fiducial volume of 100 kton and the off - axis angle of @xmath3 is assumed for the far detector .
the results are for @xmath182 and @xmath29 , and @xmath231 g/@xmath84 , see eq .
( [ eq : matteroki ] ) .
, title="fig : " ] , but for tokai - to - oki island ( @xmath70 km ) , where the fiducial volume of 100 kton and the off - axis angle of @xmath3 is assumed for the far detector .
the results are for @xmath182 and @xmath29 , and @xmath231 g/@xmath84 , see eq .
( [ eq : matteroki ] ) .
, title="fig : " ] , but for tokai - to - oki island ( @xmath70 km ) , where the fiducial volume of 100 kton and the off - axis angle of @xmath3 is assumed for the far detector .
the results are for @xmath182 and @xmath29 , and @xmath231 g/@xmath84 , see eq .
( [ eq : matteroki ] ) .
, title="fig : " ] , but for tokai - to - oki island ( @xmath70 km ) , where the fiducial volume of 100 kton and the off - axis angle of @xmath3 is assumed for the far detector .
the results are for @xmath182 and @xmath29 , and @xmath231 g/@xmath84 , see eq .
( [ eq : matteroki ] ) .
, title="fig : " ] figure [ fig : t2oki ] shows the typical event numbers for the @xmath209-like ccqe event at oki island ( @xmath70 km ) , where we suppose to place a 100 kton fiducial volume detector .
the results are for @xmath5 pot at j - parc for both @xmath6 and @xmath7 focusing beam at the off - axis angle of @xmath3 , which corresponds to the @xmath1 oab at sk , as shown in fig .
[ fig : relation ] .
we use eqs .
( [ eq : input ] ) and ( [ eq : input_rct ] ) for physics parameters and eq .
( [ eq : matteroki ] ) for the average matter density to generate these event numbers .
the left two panels in fig .
[ fig : t2oki ] , ( a1 ) and ( a2 ) , are for the @xmath6 focusing beam , while the right two panels ( b1 ) and ( b2 ) are for the @xmath7 focusing beam .
the top two panels , ( a1 ) and ( b1 ) , are for the normal mass hierarchy , and the bottom two panels , ( a2 ) and ( b2 ) , are for the inverted mass hierarchy .
the line types are the same as in fig .
[ fig : t2k ] , the red solid lines give the total event numbers , the green dashed lines are the sum of all the background events from secondary beams , the blue short dashed lines give the sum of @xmath36 and @xmath217 for the @xmath6 focusing beam , that of @xmath229 and @xmath221 for the @xmath7 focusing beam . the purple dotted lines shows the contribution from @xmath218 ( @xmath217 ) for @xmath6 ( @xmath7 ) focusing beam . as in the case of sk shown in fig .
[ fig : t2k ] , the background from the secondary beam contributions are higher for the @xmath7 focusing beam than those for the @xmath6 focusing beam . in fig .
[ fig : t2oki ] , we find that the first oscillation peak appears at around 1.0 gev at oki island for all the four cases .
the peaks at @xmath232 gev in the event numbers are obtained by the convolution of the oscillation probability , whose first peak is located around @xmath233 gev for the normal or slightly above 1 gev for the inverted hierarchy , as shown in fig .
[ fig : profile ] ( p1)-(p4 ) , and the @xmath3 oab fluxes that have a peak at around @xmath234 gev in fig .
[ fig : profile ] ( a3 ) and ( b3 ) , as shown by green dashed lines .
the difference between the normal and inverted hierarchy is larger than that of the t2k experiment .
one can observe the second peak in the 400@xmath185600 mev bin for the normal hierarchy case , ( a1 ) and ( b1 ) , but not for the inverted case .
this is because the matter effect to the oscillation phase , the term @xmath126 in eqs .
( [ eq : pme ] ) and ( [ eq : beaprox ] ) , grows with the baseline length l , and shifts the peaks of the oscillation maximum at @xmath235 in the opposite directions ; toward higher ( lower ) energies for the normal ( inverted ) hierarchy .
more accurately speaking , the above phase shift pattern applies for @xmath236 , as can be read off from eq .
( [ eq : beaprox ] ) , where the matter effect diminishes ( enhances ) the shift for the normal ( inverted ) hierarchy .
the pattern reverses for @xmath237 .
likewise , the matter effects on the oscillation amplitudes are also clearly seen : we expect more ( less ) @xmath26 events than @xmath36 events around the first oscillation peak when the hierarchy is normal ( inverted ) as can be seen from eq .
( [ eq : aeaprox ] ) .
this pattern is enhanced when @xmath230 whereas it is diminished when @xmath238 . ,
but for korea ( @xmath12 km ) , where the fiducial volume of 100 kton and the off - axis angle of @xmath13 is assumed for the far detector .
the results are for @xmath182 and @xmath29 , and @xmath239 g/@xmath84 , see eq .
( [ eq : matterkr ] ) .
, title="fig : " ] , but for korea ( @xmath12 km ) , where the fiducial volume of 100 kton and the off - axis angle of @xmath13 is assumed for the far detector .
the results are for @xmath182 and @xmath29 , and @xmath239 g/@xmath84 , see eq .
( [ eq : matterkr ] ) .
, title="fig : " ] , but for korea ( @xmath12 km ) , where the fiducial volume of 100 kton and the off - axis angle of @xmath13 is assumed for the far detector .
the results are for @xmath182 and @xmath29 , and @xmath239 g/@xmath84 , see eq .
( [ eq : matterkr ] ) .
, title="fig : " ] , but for korea ( @xmath12 km ) , where the fiducial volume of 100 kton and the off - axis angle of @xmath13 is assumed for the far detector .
the results are for @xmath182 and @xmath29 , and @xmath239 g/@xmath84 , see eq .
( [ eq : matterkr ] ) .
, title="fig : " ] in figs .
[ fig : t2kk ] , we show the typical event numbers for @xmath209-like ccqe event at a far detector in korea ( @xmath12 km ) with a 100 kton fiducial volume detector . the off - axis angle there is chosen to be @xmath13 , which optimized the t2kk performance with the @xmath1 oab at sk @xcite .
the results are for @xmath240 and @xmath29 and the parameters of eqs .
( [ eq : input ] ) and ( [ eq : input_rct ] ) , with the average matter density of 2.9 g/@xmath84 eq .
( [ eq : matterkr ] ) .
the panels and the lines types are the same as those in figs .
[ fig : t2k ] and [ fig : t2oki ] .
the first peak of the event appears at around @xmath241 gev for the @xmath6 beam for both hierarchies , but that is around 1.8 ( 1.5 ) gev for the @xmath7 beam for the normal ( inverted ) hierarchy .
this is because of the matter effect contribution to the oscillation phase , @xmath126 in eq .
( [ eq : beaprox ] ) , and @xmath162 obtained from eq .
( [ eq : beaprox ] ) by reversing the sign of @xmath83 .
the magnitude of @xmath126 is small for @xmath242 in eq .
( [ eq : beaprox ] ) , whereas that of @xmath162 is enhanced .
as expected , the sign of the difference @xmath243 in eq .
( [ eq : diff_be ] ) reflects the neutrino mass hierarchy . likewise , the difference in the heights of the first oscillation peak is more distinct in fig .
[ fig : t2kk ] for @xmath12 km then that in fig .
[ fig : t2oki ] for @xmath70 km . as expected ,
the oscillation amplitude for the @xmath26 transition is bigger ( smaller ) than that for the @xmath36 transition when the hierarchy is normal ( inverted ) .
although the magnitudes of those enhancement or suppression factor depends on @xmath144 , as can be seen from eqs .
( [ eq : aeaprox ] ) and ( [ eq : diff_ae ] ) , the difference between different baseline lengths among figs .
[ fig : t2k ] , [ fig : t2oki ] , and [ fig : t2kk ] depend solely on the mass hierarchy pattern , as expressed in eq .
( [ eq : ae_diffs ] ) .
we introduce a @xmath244 function @xmath245 in order to compare the physics potential of t2k , t2ko , and t2kk experiments quantitatively on the same footing . the first term of eq .
( [ eq : def_chi1 ] ) gives statistical constraints on the model parameters from the number of the ccqe events in each bin at each detector : @xmath246 where @xmath247 and @xmath248 denotes the number of @xmath210- and @xmath209-like events , respectively , for the @xmath6 focusing beam calculated with eq .
( [ eq : eventnu ] ) in the @xmath193-th bin at each detector , d = sk , oki , kr , whereas @xmath249 and @xmath250 are for the @xmath7 focusing beam .
their square - roots give statistical errors .
the summation is over all bins from 0.4 gev to 5.0 gev for @xmath210-like events at all sites , and for @xmath209-like events from 0.4 gev to 1.2 gev at sk , from 0.4 gev to 2.4 gev at oki , from 0.4 gev to 2.8 gev at a far detector in korea , respectively .
the input event numbers , @xmath251 , are generated with eq .
( [ eq : input ] ) for both hierarchies , and for various value of @xmath47 and @xmath10 .
we use the average matter density along each baseline of eq .
( [ eq : matter ] ) when we calculate the input event numbers .
the event numbers in the fit , @xmath252 and @xmath253 , are obtained by varying all the 6 parameters of the three - neutrino model freely and also by allowing for the systematic errors .
we consider the following systematic errors in this analysis .
we assign @xmath169 uncertainty to the overall matter density along each baseline , @xmath254 although we expect positive correlation among @xmath255 , we allow them to vary independently as a conservative estimate .
we assign @xmath256 uncertainty in the flux normalization of @xmath6 and @xmath7 focusing beam as @xmath257 [ eq : fluxfit ] @xmath131 respectively , where d = sk , oki , kr .
we also ignore possible correlations among the flux errors .
for the ccqe cross sections of neutrino and anti - neutrinos , we assume common @xmath256 error as @xmath258 [ eq : xsecfit ] @xmath20 for neutrino and anti - neutrino events , independently , but we take @xmath259 and @xmath260 because of the @xmath209-@xmath210 universality . here also , we neglect the correlation between @xmath261 and @xmath262 cross section errors .
the systematic error for the fiducial volume of each far detector is also assigned as @xmath263 summing up , we take account of 32 systematic uncertainties in terms of which @xmath264 in eq .
( [ eq : def_chi1 ] ) is expressed as @xmath265\nn\\ & & + \sum_{\beta=\ell,\bar{\ell } } \left(\dfrac{1-f_\beta}{0.03}\right)^2\ , .
\label{eq : def_chi_sys}\end{aligned}\ ] ] there are 32 normalization factors since for each detector `` d '' the fiducial volume @xmath266 , the average matter density @xmath267 , and the 4 fluxes each for @xmath6 @xmath268 and @xmath7 @xmath269 focusing beam are accounted for , in addition to the overall theoretical uncertainties for @xmath226 @xmath270 and @xmath227 @xmath271 ccqe cross sections . the last term of eq .
( [ eq : def_chi1 ] ) , @xmath272 , accounts for the external constraints on the model parameters : @xmath273 the first two terms are from the present constraints from the kamland experiment @xcite listed in eq .
( [ eq : sun_data ] ) . in the last term , we assume that the new reactor experiments @xcite will measure @xmath47 with an uncertainty of 0.01 in the near future . we do not impose the present constraints on @xmath121 and @xmath274 given in eq .
( [ eq : atm_data ] ) , since the experiments studied in this report will measure them more accurately .
in this section , we show physics capability of the t2ko experiment to determine the mass hierarchy and compare it with that of the t2kk @xcite-@xcite and the 2kn experiment . here by 2kn , we examine the option where the additional 100 kton detector is placed in the kamioka site to make the total fiducial volume 122 kton at @xmath0 km , which may be regarded as a small scale version of hyper - kamiokande @xcite . of the t2kk , t2ko , and 2kn
experiment to exclude the wrong mass hierarchy when only the @xmath6 focusing beam of @xmath275 pot is used .
four columns give results for @xmath29 , @xmath18 , @xmath276 , and @xmath277 , respectively , and the horizontal axis in each column gives the off - axis angle at sk .
the solid ( open ) square , circle , and triangle denotes , respectively , the t2kk , t2ko and 2kn results for the normal ( inverted ) hierarchy .
the results are for @xmath182 and the other input model parameters in eq .
( [ eq : input ] ) , as well as the average matter density of eq .
( [ eq : matter ] ) along the three baselines . ] in fig .
[ fig : mass1 ] , we show the minimum @xmath244 of t2kk , t2ko , and 2kn experiment for the @xmath6 focusing beam with @xmath275 pot .
four columns of fig .
[ fig : mass1 ] give results for @xmath29 , @xmath18 , @xmath276 , and @xmath277 , respectively , and the horizontal axis in each column gives the off - axis angle at the sk .
the solid ( open ) square , circle , and triangle denotes , respectively , the sensitivity of the t2kk , t2ko , and 2kn experiments for the normal ( inverted ) hierarchy .
the results are for @xmath182 and the other input model parameters in eq .
( [ eq : input ] ) , as well as the average matter density of eq .
( [ eq : matter ] ) along the three baselines . from fig .
[ fig : mass1 ] , we can tell that the physics potential for the mass hierarchy determination of the t2kk experiment is far better than the other experiments when the combination of @xmath1 oab at sk and @xmath13 oab at a far detector in korea is taken , where the mass hierarchy can be determined by more than 4@xmath8 level for all the 8 cases ( 4 values of @xmath278 and both hierarchies ) .
the sensitivity of the t2kk on the mass hierarchy reduces significantly as the off - axis angle at sk is reduced .
this is because oab with small off - axis angle can not reach korea when off - axis angle at sk is below @xmath279 @xcite ; see fig . [ fig : relation ] . for the t2ko experiment ,
the mass hierarchy can be determined at the 2@xmath8 level or higher .
this capability does not depend strongly on the off - axis angle at sk , because the beam intensity around the first peak ( @xmath232gev ) at oki island does not change much with the oab at sk , see fig .
[ fig : profile ] .
furthermore , it is clearly shown in fig . [
fig : mass1 ] that the 2kn experiment does not have any sensitivity to the neutrino mass hierarchy pattern for any combinations of @xmath10 and the mass hierarchy .
this is essentially because the small differences in the oscillation probabilities between the normal and the inverted hierarchy can easily be compensated by small shifts in the model parameters , such as @xmath121 , @xmath120 , and @xmath10 . , but with both @xmath6 and @xmath7 focusing beams each with @xmath5 pot . ] in fig .
[ fig : mass2 ] , we show the minimum @xmath244 of the t2kk , t2ko , and 2kn experiment to exclude the wrong mass hierarchy when both @xmath6 and @xmath7 focusing beams are used , each with @xmath5 pot to keep the total exposure the same . as for the t2kk experiment , shown by the red squares ,
the improvement is significant especially when @xmath280 and @xmath18 , making @xmath15 greater than 20 for all the 8 combinations of @xmath10 and sgn@xmath281 , not only for the @xmath1 oab but also for the @xmath72 oab at sk @xcite .
likewise for the t2ko experiment , shown by green circles , the improvement is most significant at @xmath282 where the smallest @xmath15 grows from @xmath283 in fig .
[ fig : mass1 ] to @xmath284 in fig .
[ fig : mass2 ] .
this is essentially because the @xmath144 term in the oscillation amplitude shift @xmath125 in eq .
( [ eq : aeaprox ] ) changes sign for the @xmath36 oscillation as shown in eq .
( [ eq : diff_ae ] ) for the difference @xmath285 .
this helps resolving the entanglement between the @xmath144 dependence ad the matter effect in the oscillation amplitudes .
significant improvements are also found for @xmath286 by the same reason .
moderate improvements are found for the @xmath29 case , allowing the t2ko experiment with half - and - half @xmath6 and @xmath7 beams to resolve the mass hierarchy at @xmath66 level for the worst case ( @xmath287 and normal hierarchy ) .
no significant dependence on the oab at sk is found .
the capability of determining the mass hierarchy pattern by the 2kn experiment does not appear even by using both @xmath6 and @xmath7 beams .
the value of @xmath15 stays almost zero , except for just two special combinations ; @xmath286 for the normal hierarchy and @xmath282 for the inverted hierarchy .
these are the two cases , where the difference between the @xmath26 and @xmath36 oscillation amplitudes , @xmath288 in eq .
( [ eq : diff_ae ] ) is largest or smallest , respectively , such that variation of the other model parameters can not account for the difference if the wrong mass hierarchy is assumed . with the same token , @xmath15 exceeds 20 for t2ko or 30 for t2kk ( with @xmath289 oab at sk ) for these two particular combinations .
contour plot for the t2ko experiment to exclude the wrong mass hierarchy in the plane of @xmath47 and @xmath10 .
the left figure is for the normal hierarchy and the right one is for the inverted hierarchy .
the oab combination for both figures is @xmath1 at sk and @xmath3 at oki island with @xmath5 pot for both @xmath6 and @xmath7 focusing beams .
contours for @xmath290 , 9 , 16 , 25 , 36 , 49 are shown .
all the input parameters other than @xmath47 and @xmath10 are shown in eqs .
( [ eq : matter ] ) and ( [ eq : input ] ) .
, title="fig : " ] contour plot for the t2ko experiment to exclude the wrong mass hierarchy in the plane of @xmath47 and @xmath10 .
the left figure is for the normal hierarchy and the right one is for the inverted hierarchy .
the oab combination for both figures is @xmath1 at sk and @xmath3 at oki island with @xmath5 pot for both @xmath6 and @xmath7 focusing beams .
contours for @xmath290 , 9 , 16 , 25 , 36 , 49 are shown .
all the input parameters other than @xmath47 and @xmath10 are shown in eqs .
( [ eq : matter ] ) and ( [ eq : input ] ) .
, title="fig : " ] so far , we have shown results for @xmath240 and 4 representative values of @xmath10 ; @xmath291 , @xmath276 , and @xmath292 . in fig . [
fig : cnt - t2oki ] , we show the contour plot of the @xmath15 for the t2ko experiment to exclude the wrong mass hierarchy in the whole plane of @xmath47 and @xmath10 : the left figure ( a ) is for the normal hierarchy , whereas the right one ( b ) is for the inverted mass hierarchy . since no strong dependence of @xmath15 on the oab angle is found for t2ko potential in fig .
[ fig : cnt - t2oki ] , we choose @xmath1 oab at sk , which gives @xmath3 oab at oki , as shown in fig .
[ fig : relation ] .
the results are for @xmath5 pot each for @xmath6 and @xmath7 focusing beam .
contours in each figure are for @xmath290 , 9 , 16 , 25 , 36 , and 49 .
the input parameters other than @xmath47 and @xmath10 are shown in eqs .
( [ eq : matter ] ) and ( [ eq : input ] ) , exactly the same as those adopted in fig .
[ fig : mass2 ] .
accordingly the @xmath15 values at @xmath182 agree exactly with those presented in fig .
[ fig : mass2 ] for t2ko with @xmath1 oab at sk , for the 4 representative @xmath10 values .
it is clearly seen from fig .
[ fig : cnt - t2oki ] that the mass hierarchy pattern can be distinguished at @xmath66 if @xmath293 for any value of @xmath294 and for both hierarchies .
the most difficult case is found for @xmath295 for the normal hierarchy , while @xmath296 for the inverted hierarchy . on the other hand ,
the discrimination is easiest at @xmath297 for the normal and at @xmath298 for the inverted hierarchy , in accordance with the argument presented above for fig .
[ fig : mass2 ] .
in addition , the contour plots fig .
[ fig : cnt - t2oki ] identify another case at @xmath299 ( @xmath300 ) for the normal ( inverted ) hierarchy , where the difference between the right and the wrong hierarchy is large , giving high @xmath15 .
the spikes of the contours around these @xmath10 values appear as a consequence of the conspiracy between the mass hierarchy dependences in the oscillation amplitude @xmath125 and in the phase shift term @xmath126 .
when @xmath301 , the @xmath26 oscillation amplitude shift @xmath125 cancels between the matter effect term and the @xmath144 term for the normal ( inverted ) hierarchy at around the tokai - to - oki baseline ; see eq .
( [ eq : aeaprox ] ) at @xmath70 km .
the cancellation is not significant at @xmath0 km for t2k , and the two effects add up constructively for @xmath36 oscillation . when the wrong hierarchy is assumed the best fit
is found for @xmath302 , for which there are two solutions , @xmath303 and @xmath304 , which have significantly different phase - shift ; see eq .
( [ eq : beaprox ] ) .
we find that the spike around @xmath305 in fig .
[ fig : cnt - t2oki ] occurs when the @xmath15 solution of the wrong hierarchy model jumps from @xmath303 to @xmath304 . , but for t2kk experiment with the optimum oab combination , @xmath1 oab at sk and @xmath13 oab at @xmath12 km .
@xmath15 values are given along the contours .
, title="fig : " ] , but for t2kk experiment with the optimum oab combination , @xmath1 oab at sk and @xmath13 oab at @xmath12 km .
@xmath15 values are given along the contours .
, title="fig : " ] figure [ fig : cnt - t2kk ] shows the same contour plots as fig .
[ fig : cnt - t2oki ] , but for t2kk with @xmath1 oab at sk and @xmath13 oab at @xmath12 km .
significant increase in the @xmath15 values at t2kk is clearly seen against those in fig .
[ fig : cnt - t2oki ] for t2ko .
now , the wrong mass hierarchy can be excluded at @xmath33 level for @xmath306 ( 0.09 ) if the mass hierarchy is normal ( inverted ) . because the measurement error is dominated by statistics , we find that the @xmath66 sensitivity of t2ko with 100 kton detector can be archived with a 40 kton detector for t2kk
. the cp phase dependence of the t2kk contours is much weaker than that of the t2ko contours , especially for smaller @xmath47 .
this is simply because the matter effect terms at @xmath307 km dominate over the @xmath144 and @xmath117 terms , in the correction terms @xmath125 and @xmath126 ; see eq .
( [ eq : abeapprox ] ) .
contour plot for the t2ko experiment in the plane of @xmath47 and @xmath10 when the mass hierarchy is assumed to be normal ( left ) or inverted ( right ) . allowed regions in the plane of @xmath47 and @xmath10
are shown for the combination of @xmath1 oab at sk and @xmath3 at oki island with @xmath5 pot each for @xmath6 and @xmath7 focusing beams .
the input values of @xmath47 is 0.04 , 0.08 , and 0.12 and @xmath10 is @xmath291 , @xmath18 , @xmath276 , and @xmath277 .
the other input parameters are given in eqs .
( [ eq : matter ] ) and ( [ eq : input ] ) .
the dotted - lines , dashed - lines , and solid - lines show @xmath308 , 4 , and 9 respectively .
the shaded region has `` mirror '' solutions for the wrong mass hierarchy giving @xmath309 .
, title="fig : " ] contour plot for the t2ko experiment in the plane of @xmath47 and @xmath10 when the mass hierarchy is assumed to be normal ( left ) or inverted ( right ) . allowed regions in the plane of @xmath47 and @xmath10
are shown for the combination of @xmath1 oab at sk and @xmath3 at oki island with @xmath5 pot each for @xmath6 and @xmath7 focusing beams .
the input values of @xmath47 is 0.04 , 0.08 , and 0.12 and @xmath10 is @xmath291 , @xmath18 , @xmath276 , and @xmath277 .
the other input parameters are given in eqs .
( [ eq : matter ] ) and ( [ eq : input ] ) .
the dotted - lines , dashed - lines , and solid - lines show @xmath308 , 4 , and 9 respectively .
the shaded region has `` mirror '' solutions for the wrong mass hierarchy giving @xmath309 .
, title="fig : " ] in this section , we investigate the measurement of cp phase @xmath10 in the t2ko experiment , as compared to the t2kk and 2kn options . in all the cases we adopt @xmath1 oab at sk , which makes the sk contribution to the measurements exactly the same , and assume @xmath5 pot each for @xmath6 and @xmath7 focusing beam .
we show in fig .
[ fig : cp - t2ko ] the @xmath15 contour plots for the t2ko experiment in the plane of @xmath47 and @xmath10 , when the mass hierarchy is assumed to be normal ( left ) or inverted ( right ) .
the 12 cases are shown in each figure for @xmath29 , @xmath18 , @xmath276 , @xmath277 , and for @xmath310 , 0.08 , and 0.12 .
the other input parameters are given in eqs .
( [ eq : matter ] ) and ( [ eq : input ] ) .
the allowed regions in the plane of @xmath47 and @xmath10 are inside of the dotted- , dashed- , and solid - contours at @xmath308 , 4 , and 9 , respectively .
the shaded region has `` mirror '' solutions for the wrong mass hierarchy giving @xmath311 , as shown by the red solid contours in fig .
[ fig : cnt - t2oki ] . since the @xmath310 input cases are no longer relevant after the measurements eqs .
( [ eq : dayabay_s13 ] ) and ( [ eq : reno_s13 ] ) by dayabay @xcite and reno@xcite , respectively , the only parameter regions where we should worry about the mirror solution with the wrong hierarchy are around @xmath280 at @xmath312 for the normal hierarchy , and around @xmath313 at @xmath312 for the inverted hierarchy .
since these regions are near the @xmath66 boundary , the mirror solutions may be excluded by extending the experimental period or by enhancing the beam power .
the @xmath310 input cases are kept , since they show the independence of the @xmath10 measurement error on @xmath47 clearly . as explained in ref.@xcite ,
this independence is a consequence of the @xmath314 enhancement of the @xmath144 and @xmath117 dependencies in @xmath125 and @xmath126 , respectively , in eqs .
( [ eq : aeaprox ] ) and ( [ eq : beaprox ] ) , which cancels precisely the statistical error which is proportional to @xmath315 , or the square - root of the @xmath26 and @xmath36 event numbers .
it is clearly seen that @xmath10 can be measured with @xmath11 error for all the 24 cases presented in fig .
[ fig : cp - t2ko ] ( a ) and ( b ) .
this is essentially because the magnitude of the coefficient of @xmath144 in the amplitude shift in eq .
( [ eq : aeaprox ] ) and that of @xmath117 in the phase shift in eq .
( [ eq : beaprox ] ) are approximately equal .
it should be noted that the uncertainty in the @xmath47 is dictated by the external constraint with the error of @xmath316 on the @xmath77 function eq .
( [ eq : def_chi1 ] ) . because of the nearly zero correlation between the errors of @xmath10 and @xmath47 in fig .
[ fig : cp - t2ko ] , further improvements in the precise measurements of @xmath47 will not reduce the errors of @xmath10 significantly . , but for t2kk experiment with @xmath1 oab at sk and @xmath13 oab at @xmath12 km .
, title="fig : " ] , but for t2kk experiment with @xmath1 oab at sk and @xmath13 oab at @xmath12 km .
, title="fig : " ] in order to compare the sensitivity of the @xmath10 measurement between the t2ko and the t2kk experiments , we show in fig .
[ fig : cp - t2kk ] the same contours for the t2kk experiment with @xmath1 oab at sk and @xmath13 oab at @xmath12 km .
it is clearly seen from the 12 sets of contours , each for normal ( left ) and inverted ( right ) hierarchy , that the expected error of @xmath10 is @xmath11 for all the combinations , just as for the t2ko experiment shown in fig .
[ fig : cp - t2ko ] .
this is remarkable since the event number at a far detector in korea at @xmath317 km is significantly smaller than that in oki at @xmath70 km because of the flux which decreases as @xmath203 at long distances .
this decrease the overall flux is compensated by the wide - band structure of the @xmath13 oab as shown by blue dotted lines in fig .
[ fig : profile ] ( a3 ) and ( b3 ) , which enables the far detector in korea to observe not only the first oscillation peak but also the second one as in fig .
[ fig : t2kk ] . around the second peak , @xmath318 , and
the sensitivity to @xmath144 and @xmath117 can be three times higher than the first peak with @xmath319 ; see eqs .
( [ eq : abeapprox ] ) and ( [ eq : diff_ae_and_be ] ) .
in addition , the extended energy range covered by the @xmath13 oab allows the t2kk experiment to measure the phase - shifts @xmath126 and @xmath162 accurately , and hence @xmath117 ; see eqs .
( [ eq : beaprox ] ) and ( [ eq : diff_be ] ) .
indeed , we notice in fig .
[ fig : cp - t2kk ] ( a ) and ( b ) that the error of @xmath10 can be as small as @xmath320 when @xmath29 or @xmath276 . contour plot for the 2kn experiment in the plane of @xmath47 and @xmath10 when the mass hierarchy is assumed to be normal ( @xmath321 ) . allowed regions in the plane of @xmath47 and @xmath10
are shown for experiments with @xmath5 pot each for @xmath6 and @xmath7 focusing beam at @xmath1 off - axis angle .
the input values of @xmath47 are 0.04 , 0.08 , and 0.12 and @xmath10 are @xmath291 ( a ) , @xmath18 ( b ) , @xmath276 ( c ) , and @xmath277 ( d ) .
the other input parameters are listed in eqs .
( [ eq : input ] ) and ( [ eq : matter ] ) .
the red dotted - lines , dashed - lines , and solid - lines show @xmath308 , 4 , and 9 contours , respectively , when the right mass hierarchy is assumed in the fit , whereas the blue contours give @xmath15 measured from the local minimum value ( shown besides the @xmath322 symbol ) at the cross point when the wrong hierarchy is assumed in the fit .
, title="fig : " ] contour plot for the 2kn experiment in the plane of @xmath47 and @xmath10 when the mass hierarchy is assumed to be normal ( @xmath321 ) . allowed regions in the plane of @xmath47 and @xmath10
are shown for experiments with @xmath5 pot each for @xmath6 and @xmath7 focusing beam at @xmath1 off - axis angle .
the input values of @xmath47 are 0.04 , 0.08 , and 0.12 and @xmath10 are @xmath291 ( a ) , @xmath18 ( b ) , @xmath276 ( c ) , and @xmath277 ( d ) .
the other input parameters are listed in eqs .
( [ eq : input ] ) and ( [ eq : matter ] ) .
the red dotted - lines , dashed - lines , and solid - lines show @xmath308 , 4 , and 9 contours , respectively , when the right mass hierarchy is assumed in the fit , whereas the blue contours give @xmath15 measured from the local minimum value ( shown besides the @xmath322 symbol ) at the cross point when the wrong hierarchy is assumed in the fit .
, title="fig : " ] contour plot for the 2kn experiment in the plane of @xmath47 and @xmath10 when the mass hierarchy is assumed to be normal ( @xmath321 ) . allowed regions in the plane of @xmath47 and @xmath10
are shown for experiments with @xmath5 pot each for @xmath6 and @xmath7 focusing beam at @xmath1 off - axis angle .
the input values of @xmath47 are 0.04 , 0.08 , and 0.12 and @xmath10 are @xmath291 ( a ) , @xmath18 ( b ) , @xmath276 ( c ) , and @xmath277 ( d ) .
the other input parameters are listed in eqs .
( [ eq : input ] ) and ( [ eq : matter ] ) .
the red dotted - lines , dashed - lines , and solid - lines show @xmath308 , 4 , and 9 contours , respectively , when the right mass hierarchy is assumed in the fit , whereas the blue contours give @xmath15 measured from the local minimum value ( shown besides the @xmath322 symbol ) at the cross point when the wrong hierarchy is assumed in the fit .
, title="fig : " ] contour plot for the 2kn experiment in the plane of @xmath47 and @xmath10 when the mass hierarchy is assumed to be normal ( @xmath321 ) . allowed regions in the plane of @xmath47 and @xmath10 are shown for experiments with @xmath5 pot each for @xmath6 and @xmath7 focusing beam at @xmath1 off - axis angle .
the input values of @xmath47 are 0.04 , 0.08 , and 0.12 and @xmath10 are @xmath291 ( a ) , @xmath18 ( b ) , @xmath276 ( c ) , and @xmath277 ( d ) .
the other input parameters are listed in eqs .
( [ eq : input ] ) and ( [ eq : matter ] ) .
the red dotted - lines , dashed - lines , and solid - lines show @xmath308 , 4 , and 9 contours , respectively , when the right mass hierarchy is assumed in the fit , whereas the blue contours give @xmath15 measured from the local minimum value ( shown besides the @xmath322 symbol ) at the cross point when the wrong hierarchy is assumed in the fit . , title="fig : " ] , but for the inverted mass hierarchy ( @xmath323 ) .
, title="fig : " ] , but for the inverted mass hierarchy ( @xmath323 ) .
, title="fig : " ] , but for the inverted mass hierarchy ( @xmath323 ) .
, title="fig : " ] , but for the inverted mass hierarchy ( @xmath323 ) .
, title="fig : " ] finally in figs .
[ fig : cp - t2kn ] and [ fig : cp - t2ki ] , we show the allowed regions by the 2kn experiment in the plane of @xmath47 and @xmath10 for the normal ( fig . [
fig : cp - t2kn ] ) and the inverted ( fig .
[ fig : cp - t2ki ] ) mass hierarchy , when both @xmath6 and @xmath7 focusing beam at @xmath1 off - axis angle are used each with @xmath5 pot .
the four @xmath10 cases of @xmath291(a ) , @xmath18(b ) , @xmath276(c ) , @xmath277(d ) are examined for the three @xmath324 , 0.08 , 0.12 , just as in fig .
[ fig : cp - t2ko ] for t2ko and fig .
[ fig : cp - t2kk ] for t2kk .
the other input parameters are also the same , taken from eqs .
( [ eq : matter ] ) and ( [ eq : input ] ) .
the red dotted - lines , dashed - lines , and solid - lines show @xmath308 , 4 , 9 contours , respectively , when the right mass hierarchy is assumed in the fit , whereas the blue contours gives @xmath15 measured from the local minimum at the blue cross point when the wrong hierarchy is assumed in the fit .
the local minimal value of @xmath15 at the blue cross point is given besides the cross mark in the corresponding input @xmath47 column .
as has been explained in section [ sec : mass ] and shown in fig .
[ fig : mass2 ] , the local @xmath15 values are significant only for @xmath325 when the hierarchy is normal ( fig .
[ fig : cp - t2kn ] ( d ) ) , and for @xmath326 when the hierarchy is inverted ( fig .
[ fig : cp - t2ki ] ( b ) ) . in order to show the location of the input parameters clearly
, we show the global minimal point by the red solid blob for each input parameter case .
the global minimum gives @xmath327 in our analysis which ignores fluctuations in the mean number of events in each bin .
we first note that @xmath10 can be constrained uniquely around the above two specific cases ( @xmath328 for @xmath57 , or @xmath329 for @xmath58 ) , since not only the wrong mass hierarchy assumption gives non - negligible local @xmath15 as given in fig .
[ fig : cp - t2kn ] ( d ) and fig .
[ fig : cp - t2ki ] ( b ) , but also the wrong hierarchy assumption favors the right @xmath10 , with slightly larger ( smaller ) fitted @xmath47 that compensate for the matter effect for the normal ( inverted ) hierarchy . the @xmath330 error shown by the red dotted contour is rather large , however , about @xmath331 . in all the other cases ,
the presence of the wrong hierarchy solutions as shown by blue contours significantly reduce the capability of measuring @xmath10 with 2kn .
more importantly , even if we can remove the wrong hierarchy by other experiments such as nova @xcite , the next generation reactor neutrino oscillation experiments @xcite , or by an atmospheric neutrino observation with a huge detector @xcite , the 2kn experiment with only one baseline length can not measure @xmath10 with high accuracy when @xmath332 , or suffers from the @xmath333 solution when @xmath334 or @xmath276 as can be seen from the separate red contour islands on the ( a ) and ( c ) plots in figs .
[ fig : cp - t2kn ] and [ fig : cp - t2ki ] . throughout the analysis of this and the previous sections we fix the oab at sk at @xmath1 in order to make the sk contributions to all the three experiments t2ko , t2kk and 2kn identical .
we find that the performance of 2kn slightly improves if the @xmath335 oab is adopted instead , mainly because these fluxes are slightly wider ( harder ) than the @xmath1 oab as shown by red solid curves in figs .
[ fig : profile ] ( a1)-(a3 ) , ( b1)-(b3 ) .
in this paper , we examine physics potential of a one - beam two - detectors neutrino oscillation experiment with an additional 100 kton water detector in oki island , which is located along the t2k beam line at the baseline length of @xmath70 km . together with super - kamiokande ( sk ) at @xmath0 km
, we can measure neutrino oscillations at two different energies for the same oscillation phase proportional to @xmath336 .
we may call this proposal as t2ko ( tokai - to - kamioka - and - oki ) , whose capability has been compared with t2kk ( tokai - to - kamioka - and - korea ) with @xmath317 km for the far detector in korea , and also with 2kn where the same 100 kton detector is placed at the sk site ( @xmath0 km ) . as shown in fig .
[ fig : t2oki1 ] , since the oki island is located in the east side of the t2k beam center , just like the sk , the off - axis angle at oki island increases as that at sk increases , as shown in fig .
[ fig : relation ] . the off - axis beam ( oab ) with @xmath3 , @xmath337 , and @xmath4 from j - parc can be observed at oki island , when the @xmath1 , @xmath72 , and @xmath2 oab reaches at sk , respectively .
the neutrino energy of the first oscillation maximum for the @xmath338 and @xmath339 is between 1.0 gev and 1.5 gev , which depend on the cp phase and the mass hierarchy pattern , at @xmath340 km . since the @xmath6 ( @xmath7 ) beam between @xmath4 and @xmath3 off - axis angles has significant intensity around these energies , as shown by green dashed lines in the upper six panels in fig .
[ fig : profile ] , we expect that the t2ko experiment can be sensitive to the neutrino mass hierarchy and the cp phase , just like the t2kk experiment @xcite , @xcite-@xcite . for a detector of 100 kton fiducial volume and @xmath5 pot exposure each for both @xmath6 and @xmath7 beams ,
we find that the t2ko experiment can determine the mass hierarchy pattern at @xmath66 level if @xmath341 is larger than 0.09 , by observing the @xmath209-like ccqe ( charged - current quasi elastic ) events ; see fig . [ fig : cnt - t2oki ] . this result does not strongly depend on the off - axis angle of the @xmath6 ( @xmath7 ) beam at oki island , because the neutrino intensity at the first oscillation maximum does not strongly depend on the off - axis angle at oki island .
the t2ko sensitivity to the mass hierarchy is about @xmath14 ( in @xmath15 ) of the t2kk experiment with the optimum oab combination of @xmath1 at sk and @xmath13 at a far detector in korea with the baseline length around 1000 km .
this is because the factor of two higher sensitivity of the t2kk over the t2ko experiment as shown by eqs .
( [ eq : ae_diffs ] ) and ( [ eq : be_diffs ] ) , which should give a factor of 4 in @xmath15 is partially compensated by the smaller average flux by a factor of ( 635 km/1000 km)@xmath342 at a far detector in korea .
the sensitivity of the mass hierarchy pattern of the 2kn experiment , where a 100 kton detector is added at the sk location , is almost zero , except around @xmath297 ( @xmath18 ) for the normal ( inverted ) hierarchy ; see fig .
[ fig : mass2 ] . the cp phase in the mns ( maki - nakagawa - sakata ) lepton flavor mixing matrix @xcite , @xmath10 can be measured with @xmath11 error for all the four cases at @xmath29 , @xmath343 , and @xmath276 , almost independent of the @xmath47 values @xcite as long as the neutrino mass hierarchy is determined .
this is because @xmath144 can be constrained by the difference between the magnitudes of the oscillation probabilities @xmath338 and @xmath339 around the oscillation maximum , whereas @xmath117 can be determined by the oscillation phase around the first oscillation maximum , or the location of the oscillation peak(s ) ; see eqs .
( [ eq : aeaprox ] ) and ( [ eq : diff_ae ] ) .
the sensitivity to the cp phase , @xmath10 , of the t2ko experiment is similar to that of the t2kk experiment , mainly because the smallness of the flux at t2kk is compensated by its capability to measure the second oscillation peak at @xmath344 when the sensitivity to both @xmath117 and @xmath144 is a factor of 3 higher than that around the first peak ; see eqs .
( [ eq : abeapprox ] ) .
the 2kn option , which may be regarded as a first step toward the hyper - kamiokande @xcite , can not generally determine @xmath10 , mainly because it can not resolve mass hierarchy by itself .
only when @xmath345 for the normal hierarchy ( see , fig .
[ fig : cp - t2kn ] ( d ) ) and when @xmath329 for the inverted hierarchy ( see , fig .
[ fig : cp - t2ki ] ( b ) ) , the constraints for both hierarchy assumptions overlap , and the cp phase can be determined uniquely . even if the mass hierarchy is determined by other experiments @xcite ,
@xcite-@xcite the sensitivity to @xmath10 is rather poor at 2kn as shown in figs .
[ fig : cp - t2kn ] and [ fig : cp - t2ki ] .
this is essentially because of the parameter degeneracy unavoidable in experiments with only one baseline length , such as those between @xmath10 and @xmath346 when @xmath347 .
we would like to thank our experimentalist colleagues y. hayato , a.k .
ichikawa , t. kobayashi , and t. nakaya , from whom we learn about the k2k and t2k experiments .
we thank n. isezaki and m. komazawa for teaching us about the geophysics measurements in the sea of japan , or the east sea of korea .
we are also grateful to japanese coast guard for showing the detailed geological information around oki island .
the numerical calculations have been carried out on kekcc at kek .
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smirnov , arxiv:1205.7071(hep - ph ) . | oki island is located between japan and korea along the tokai - to - kamioka ( t2k ) baseline .
the distance from j - parc to oki island is about 653 km , which is twice that of the t2k experiment ( @xmath0 km ) .
when the off - axis angle of the neutrino beam from j - parc is @xmath1 ( @xmath2 ) at super - kamiokande ( sk ) , the off - axis beam ( oab ) with @xmath3 ( @xmath4 ) reaches at oki island .
we examine physics case of placing a far detector in oki island during the t2k experimental period .
we estimate the matter density profile along the tokai - to - oki baseline by using recent seismological measurements . for a detector of 100 kton
fiducial volume and @xmath5 pot ( protons on target ) exposure for both @xmath6 and @xmath7 beams , we find that the mass hierarchy pattern can be distinguished at 3 @xmath8 level if @xmath9 , by observing the electron - like ccqe ( charged - current quasi elastic ) events . the cp phase in the maki - nakagawa - sakata lepton flavor mixing matrix , @xmath10 , can be constrained with @xmath11 . as a reference , we repeat the same analysis by placing the same detector in korea at @xmath12 km and oab=@xmath13 ( t2kk ) and also by placing it at the sk site ( 2kn ) .
the tokai - to - kamioka - oki ( t2ko ) sensitivity to the mass hierarchy is about @xmath14 ( in @xmath15 ) of t2kk , while the sensitivity to the phase @xmath10 is similar between t2ko and t2kk .
the t2k@xmath16 option has almost no sensitivity to the mass hierarchy , and can not measure the cp phase except when @xmath17 ( @xmath18 ) for the normal ( inverted ) hierarchy .
kek - th-1568 |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Preserving Independence of Financial
Institution Examinations Act of 2003''.
SEC. 2. OFFER AND ACCEPTANCE OF CREDIT.
(a) In General.--Title 18, United States Code, is amended by
striking sections 212 and 213 and inserting the following:
``Sec. 212. Offer of loan or gratuity to financial institution examiner
``(a) In General.--Except as provided in subsection (b), whoever,
being an officer, director, or employee of a financial institution,
makes or grants any loan or gratuity, to any examiner or assistant
examiner who examines or has authority to examine such bank, branch,
agency, organization, corporation, association, or institution--
``(1) shall be fined under this title, imprisoned not more than
1 year, or both; and
``(2) may be fined a further sum equal to the money so loaned
or gratuity given.
``(b) Regulations.--A Federal financial institution regulatory
agency may prescribe regulations establishing additional limitations on
the application for and receipt of credit under this section and on the
application and receipt of residential mortgage loans under this
section, after consulting with each other Federal financial institution
regulatory agency.
``(c) Definitions.--In this section:
``(1) Examiner.--The term `examiner' means any person--
``(A) appointed by a Federal financial institution
regulatory agency or pursuant to the laws of any State to
examine a financial institution; or
``(B) elected under the law of any State to conduct
examinations of any financial institutions.
``(2) Federal financial institution regulatory agency.--The
term `Federal financial institution regulatory agency' means--
``(A) the Office of the Comptroller of the Currency;
``(B) the Board of Governors of the Federal Reserve System;
``(C) the Office of Thrift Supervision;
``(D) the Federal Deposit Insurance Corporation;
``(E) the Federal Housing Finance Board;
``(F) the Farm Credit Administration;
``(G) the Farm Credit System Insurance Corporation; and
``(H) the Small Business Administration.
``(3) Financial institution.--The term `financial institution'
does not include a credit union, a Federal Reserve Bank, a Federal
home loan bank, or a depository institution holding company.
``(4) Loan.--The term `loan' does not include any credit card
account established under an open end consumer credit plan or a
loan secured by residential real property that is the principal
residence of the examiner, if--
``(A) the applicant satisfies any financial requirements
for the credit card account or residential real property loan
that are generally applicable to all applicants for the same
type of credit card account or residential real property loan;
``(B) the terms and conditions applicable with respect to
such account or residential real property loan, and any credit
extended to the examiner under such account or residential real
property loan, are no more favorable generally to the examiner
than the terms and conditions that are generally applicable to
credit card accounts or residential real property loans offered
by the same financial institution to other borrowers
cardholders in comparable circumstances under open end consumer
credit plans or for residential real property loans; and
``(C) with respect to residential real property loans, the
loan is with respect to the primary residence of the applicant.
``Sec. 213. Acceptance of loan or gratuity by financial institution
examiner
``(a) In General.--Whoever, being an examiner or assistant
examiner, accepts a loan or gratuity from any bank, branch, agency,
organization, corporation, association, or institution examined by the
examiner or from any person connected with it, shall--
``(1) be fined under this title, imprisoned not more than 1
year, or both;
``(2) may be fined a further sum equal to the money so loaned
or gratuity given; and
``(3) shall be disqualified from holding office as an examiner.
``(b) Definitions.--In this section, the terms `examiner', `Federal
financial institution regulatory agency', `financial institution', and
`loan' have the same meanings as in section 212.''.
(b) Technical and Conforming Amendment.--The table of sections of
chapter 11 of title 18, United States Code, is amended by striking the
matter relating to sections 212 and 213 and inserting the following:
``212. Offer of loan or gratuity to financial institution examiner.
``213. Acceptance of loan or gratuity by financial institution
examiner.''.
Speaker of the House of Representatives.
Vice President of the United States and
President of the Senate. | Preserving Independence of Financial Institution Examinations Act of 2003 - Amends Federal criminal law to subject to criminal penalties: (1) personnel of a financial institution who offer a loan or gratuity to a financial institution examiner; and (2) a financial institution examiner who accepts such loan or gratuity.
Authorizes a Federal financial institution regulatory agency to prescribe regulations establishing additional limitations on the application for and receipt of credit and on the application and receipt of residential mortgage loans, after consulting with each other Federal financial institution regulatory agency.
Excludes from the meaning of financial institution covered by this Act a credit union, a Federal Reserve Bank, a Federal home loan bank, or a depository institution holding company.
Declares that the term "loan" does not include any credit card account established under an open end consumer credit plan, or a loan secured by residential real property that is the principal residence of the examiner, if certain requirements are met. |
let @xmath0 be a lie group over @xmath1 ( or @xmath2 ) , and @xmath3 its lie algebra .
there exists an open neighbourhood @xmath4 of the origin @xmath5 such that the restriction to @xmath4 of the exponential map @xmath6 is an analytic diffeomorphism .
we denote by @xmath7 the inverse map and by @xmath8 the generating series of bernoulli numbers .
it is convenient to have a separate notation for the function @xmath9 . in * @xcite * , kashiwara and vergne put forward the following conjecture on the properties of the campbell - hausdorff series : 0.5 cm * kashiwara - vergne conjecture .
* there exists a pair of @xmath3-valued analytic functions @xmath10 and @xmath11 defined on an open subset @xmath12 containing @xmath13 , such that @xmath14 , and for any @xmath15 one has @xmath16 where @xmath17 are defined as follows , @xmath18 0.3 cm sometimes this statement is referred to as the ` combinatorial kashiwara - vergne conjecture ' ( see _ e.g. _ * @xcite * ) .
this conjecture was established for solvable lie algebras in * @xcite * and for quadratic lie algebras in * @xcite*. recently , the general case was settled in * @xcite * based on the earlier work * @xcite*. we denote by @xmath19 $ ] and @xmath20 $ ] the ring of formal power series and the ring of polynomials , respectively .
we call a solution of the kashiwara - vergne conjecture _ universal _ if @xmath10 and @xmath11 are given by series in lie polynomials of the variables @xmath21 and @xmath22 : @xmath23 with @xmath24 , @xmath25 $ ] , @xmath26 , and both @xmath27 are of type @xmath28 if @xmath29 is a universal solution , the coefficients of the taylor expansions of @xmath10 and @xmath11 are the same for all lie algebras over @xmath30 .
the set of solutions of the kashiwara - vergne conjecture carries a natural @xmath31-action , @xmath32 a solution is called _ symmetric _ if it is stable with respect to this action .
averaging of any solution produces a symmetric solution .
hence , without loss of generality we can restrict our attention to symmetric solutions .
it is well - known ( see _ e.g. _ * @xcite * ) that @xmath33 and @xmath24 are uniquely determined by the kashiwara - vergne equations and by the symmetry condition . in this note
we prove the uniqueness statement for the function @xmath34 .
thus , the symmetric universal solution of the kashiwara - vergne conjecture is unique up to order one in @xmath22 . in the appendix by the second author
, this result is applied to show that solutions of the kashiwara - vergne conjecture for quadratic lie algebras obtained in * @xcite * and * @xcite * are not universal .
in this section , we collect some elementary properties of lie algebras . * ( free lie algebras with two generators ) . * [ bella ] we denote by @xmath35 the free lie @xmath30-algebra with generators @xmath36 and @xmath37 . in this section
we use the hall basis @xmath38 of @xmath35 defined in * @xcite * ( definition 2 , page 27 ) .
@xmath38 consists of lie words with the following order relation : @xmath39 and @xmath40 ; if the number of lie brackets in @xmath41 is smaller than the number of lie brackets in @xmath42 then @xmath43 ; and we omit the description of the order relation for @xmath44 and @xmath45 of equal length . the basis @xmath38 is built inductively starting with @xmath46 $ ] , and one adds the elements of the form @xmath47 $ ] such that @xmath48\in h$ ] , @xmath49 $ ] , and @xmath50 . using the definition of @xmath38 we can prove by induction that @xmath51 in fact , the cases @xmath52 and @xmath53 are trivial , and for @xmath54 we use @xmath55 $ ] . furthermore , @xmath56 , 0\leq j < n - j ,
j\leq n-1 \right\ } \subset h .\ ] ] here it is sufficient to observe that @xmath57 $ ] . [ lem21 ] let @xmath58 $ ] .
the following statements are equivalent : 1 . for any lie @xmath30-algebra @xmath3
we have @xmath59 @xmath60 ; 2 .
@xmath61 .
it is sufficient to show that @xmath62 implies @xmath63 .
let @xmath64 . by rescaling @xmath65 and applying @xmath66 we get @xmath67 .
choosing @xmath68 , @xmath69 and @xmath70 we get @xmath71
. the following will be a very useful notation .
let @xmath72 .
for any pair @xmath73 , we set @xmath74)_y : = [ ( { { \rm ad } } y)^i ( w ) , ( { { \rm ad } } y)^j ( x ) ] .\ ] ] this notation is extended by linearity to any formal power series @xmath75 $ ] .
then @xmath76)_y\in { { \eufrak g } } [ [ { { \eufrak g } } ] ] $ ] is a formal power series with coefficients in @xmath3 . [ oss22 ] 1 .
@xmath77)_y = - ( u^it^j : [ x , w])_y $ ] .
2 . jacobi s identity gives @xmath78)_y = ( { { \rm ad } } y)([w , x])$ ] .
[ lem23 ] let @xmath79 be a series in @xmath80 $ ] .
the following statements are equivalent : 1 . for any lie @xmath30-algebra @xmath3
we have @xmath81)_y = 0 \ \ \forall x , y\in{{\eufrak g } } $ ] ; 2 .
. recall that @xmath83)_y = [ x , \xi ( { { \rm ad } } y)(x ) ] $ ] .
similar to the proof of proposition [ lem21 ] , it is sufficient to show that in the free lie algebra @xmath84 we have @xmath85 \neq 0 $ ] for any @xmath86 .
indeed , if we rename @xmath87 , the elements @xmath88 $ ] belong to the basis @xmath38 and , hence , are non - vanishing
. every formal power series @xmath75 $ ] can be split into the sum of its symmetric and skew - symmetric parts : @xmath89 [ cor21 ] let @xmath75 $ ] .
the following statements are equivalent : 1 . for any lie @xmath30-algebra @xmath3
we have @xmath90)_y = 0 $ ] @xmath60 ; 2 .
@xmath91 . by skew - symmetry of the lie bracket ,
@xmath92)_y = 0 $ ] for any @xmath93 , and @xmath90)_y = ( \xi(t , u)_{skew } : [ x , x])_y$ ] .
let @xmath94 be a formal power series with vanishing symmetric part .
then , it can be written as @xmath95 suppose that @xmath96)_y \equiv \sum_{n=1}^\infty \sum_{0\leq j
< n - j } \xi_{n , j } [ ( { { \rm ad } } y)^j x , ( { { \rm ad } } y)^{n - j } x ] = 0\ ] ] for every lie @xmath30-algebra @xmath3 and every @xmath97 . by rescaling @xmath98 and then applying the @xmath99-th derivative in @xmath100 we get @xmath101 = 0 .\ ] ] then we choose @xmath68 , @xmath102 and @xmath102 .
since all lie words in the sum are linearly independent ( recall property ( [ tm21 ] ) ) this implies @xmath103 for all @xmath104 and @xmath105 .
[ l14 ] in the lie algebra @xmath35 we have @xmath106)_x \notin span_{\mathbb{k}}\ { \big ( ( t+u)t^lu^m : [ y , y]\big)_x | l , m\in{\mathbb{n}}\ } .\ ] ] we want to show that @xmath107)_x \notin span_{\mathbb{k}}\ { ( ( t+u)t^lu^{2n - l } : [ y , y])_x | 0\leq l\leq 2n \ } .
$ ] if @xmath52 this statement is obvious .
let @xmath54 , and suppose that we can some find coefficients @xmath108 such that @xmath109)_x = \sum_{j=0}^{2n } c_j ( ( t+u)u^{2n - j}t^j:[y , y])_x .\ ] ] let @xmath110 , then identity ( [ ultima ] ) can be written as @xmath111)_x=0 $ ] .
the universal property of a free lie algebra allows to apply proposition [ cor21 ] , so @xmath91 .
this means that @xmath112 modulo @xmath113 , and this is a contradiction .
[ fine ] here we explain that propositions [ lem21 ] , [ lem23 ] , and [ cor21 ] still apply if we restrict to finite - dimensional lie algebras . in their proofs , at some point
we choose @xmath3 equal to the free lie algebra @xmath35 .
let @xmath114 .
we introduce @xmath115 , where @xmath116 is an ideal of @xmath35 such that @xmath117 is an @xmath118-nilpotent lie algebra .
in particular @xmath117 is a finite - dimensional lie algebra with basis @xmath119 . to modify the proofs it is sufficient to replace @xmath35 with @xmath117 , for a good choice of @xmath118 : @xmath120 in proposition [ lem21 ] , @xmath121 in proposition [ lem23 ] , and @xmath122 in proposition [ cor21 ] . in the previous theorems we do not use lie groups .
we end this section by computing some derivatives of the exponential map of a lie group @xmath0 with lie algebra @xmath3 .
let @xmath123 .
we use the notation @xmath124 for the right translation . in the following lemma
we denote by @xmath125 the group unit of @xmath0 .
[ lemma21 ] let @xmath97 , then 1 .
@xmath126 , 2 .
@xmath127 , 3 .
@xmath128 \right)_x $ ] .
@xmath62 the formula of this differential is a consequence of the well - known formula for the differential of the exponential map : @xmath129 @xmath63 using part @xmath62 and @xmath130 we get @xmath131 formula ( [ difexp ] ) gives @xmath132 , so @xmath133 @xmath134 using @xmath63 , @xmath62 and a direct calculation we get & & |_s=0 r_exp(x)(exp(sy))= + & & = ( : [ |_s=0r_exp(x)(exp(sy)),y ] ) _ x + & & ( : [ _ 1 ( ad x)(y),y ] ) _ x .
in this section we only make use of equation ( [ primae ] ) , and we derive formulas for @xmath24 , @xmath135 , and @xmath136 . [ tm31bis ] a universal solution of the kashiwara - vergne conjecture has @xmath137 in ( [ primae ] ) we rescale @xmath22 by @xmath138 and we compute the derivative in @xmath139 : @xmath140 using lemma [ lemma21 ] part @xmath141 and @xmath142 , we get @xmath143 as this identity has to be verified for any @xmath30-lie algebra @xmath3 and for any @xmath97 , proposition [ lem21 ] implies @xmath144 .
the following theorem uses the notation @xmath145)_x , \ ] ] where the formal power series @xmath146 $ ] is skew - symmetric ( i.e @xmath147 ) .
[ tm31 ] a universal solution of the kashiwara - vergne conjecture has 1 .
@xmath148 2 .
@xmath149 by rescaling @xmath150 and then applying the second derivative in @xmath151 to equation ( [ primae ] ) we obtain , @xmath152)_x .\ ] ] here we have used that @xmath153)_x .
\end{aligned}\ ] ] let @xmath154 .
the comparison of part @xmath134 of lemma [ lemma21 ] with equation ( [ d^2 ] ) gives @xmath155 \right)_x = ( 1-e^ { { { \rm ad } } x})a_2(x , y ) \equiv \left ( ( 1-e^{t+u})\pi(t , u):[y , y ] \right)_x\end{aligned}\ ] ] for any @xmath97 and any lie @xmath30-algebra @xmath3 .
let @xmath156 .
proposition [ cor21 ] gives @xmath157 , in particular @xmath158 putting @xmath159 we get statement @xmath62 .
to get statement @xmath63 it is sufficient to remark that @xmath160 .
in this section we derive formulas for @xmath161 and @xmath34 . we begin with a technical remark . [ os41 ]
let @xmath162 be two distinct numbers , and @xmath163 be the 3-dimensional lie algebra with lie brackets @xmath164=0,\ [ a , c]=\lambda c,\ [ b , c]=\mu c.$ ] it is easy to see that @xmath165 = 0 $ ] , and as a consequence @xmath166 .
moreover , for any @xmath167 $ ] one has @xmath168 [ tm41 ] a universal solution of the kashiwara - vergne conjecture has @xmath169 let @xmath170 , we have @xmath171 and @xmath172 let @xmath3 be the lie algebra in remark [ os41 ] , @xmath173 , and @xmath174 .
we get @xmath175 in particular equation ( [ secondae ] ) gives @xmath176 rescaling @xmath44 , @xmath45 and using the properties of @xmath177 we get & & = 0 , + & & ( t ) - ( t ) + ( 0 ) + (t ) - (0 ) = 0 .
if one replaces @xmath178 by a series @xmath179 $ ] one gets another conjecture that one can call an @xmath180-kashiwara - vergne conjecture .
then , 1
. theorem [ tm41 ] is modified by replacing @xmath178 by @xmath180 and adding @xmath181 in the conclusion .
theorems [ tm31bis ] , [ tm31 ] , and part @xmath62 imply @xmath182 , otherwise a universal solution of the @xmath180-kashiwara - vergne conjecture does not exist .
3 . if a universal solution of the @xmath180-kashiwara - vergne conjecture has @xmath183 then one can show that @xmath184 ( we stress that @xmath185 ) . to get an easy proof one can use the lie algebra of remark [ os41 ]
in the previous sections we did not determine the value of the constant @xmath186 . imposing the symmetry condition we obtain @xmath187 , so @xmath188 .
hence a universal symmetric solution has @xmath189 .
vergne and alekseev - meinrenken both considered a quadratic lie algebra and obtained symmetric solutions .
it is natural to ask whether these solutions are universal .
in fact , quadratic lie algebras have the special property @xmath190 for any @xmath64 and any couple of vectors @xmath191 , which simplifies the equation with traces ( [ secondae ] ) .
we have seen that a universal symmetric solution of the kashiwara - vergne conjecture has @xmath192)_x + o(y^2)\end{aligned}\ ] ] with @xmath193 given in theorem [ tm31bis ] , and @xmath194 given in theorem [ tm31 ] . *
( vergne s solution for quadratic lie algebras ) * [ rem51 ] we denote by @xmath195 the @xmath11 found by m. vergne in * @xcite*. following her paper we find @xmath196 .
let @xmath197 after a bit long calculation we see that the series @xmath198 is given by @xmath199 this differential equation gives @xmath200 .
a universal solution has @xmath201 in particular the symmetric solution found by m. vergne for a quadratic lie algebra is not universal .
following their paper * @xcite * and the paper * @xcite * of m. vergne , after some efforts we find the following formulas .
let @xmath204 , and @xmath205 be the formal power series such that @xmath206 then @xmath207 using maple we get @xmath208 , @xmath209 , and @xmath210 in particular the symmetric solution of alekseev and meinrenken is not universal , and it is different from the solution of vergne . | we prove that a universal symmetric solution of the kashiwara - vergne conjecture is unique up to order one . in the appendix by the second author
, this result is used to show that solutions of the kashiwara - vergne conjecture for quadratic lie algebras existing in the literature are not universal . +
* keywords . * campbell - hausdorff series , free lie algebras , differential of the exponential map , bernoulli numbers . |
we surveyed 2 rural communities in southeastern bolivia : bartolo in hernando siles province , department of chuquisaca ; and casas viejas in vallegrande province , department of santa cruz .
persons live in close contact with animals , mainly swine , in the absence of adequate housing or fencing .
informed consent to obtain samples was obtained from all adults and from parents of minors participating in the survey .
the study design , including its ethical aspects , was approved by the bolivian ministry of health and the local health authorities .
blood samples were taken from 236 persons ( 172 in bartolo and 64 in casas viejas , age range 187 years ) .
individual fecal samples were obtained from 122 persons ( 90 in bartolo and 32 in casas viejas , age range 362 years ) .
feces samples were combined into 22 pools ( 16 in bartolo and 6 in casas viejas ) .
each pool consisted of 410 individual fecal samples from persons of the same age range .
individual fecal samples were taken also from 121 swine ( 67 in bartolo and 54 in casas viejas , age range 212 months ) and combined into 22 pools ( 13 in bartolo and 9 in casas viejas ) .
samples from persons with fecal samples positive for hev rna were also tested for igm against hev by using commercial elisa kits ( hev igg / igm ; dia.pro srl , milan , italy ) .
hev rna was detected by using reverse transcription pcr ( rt - pcr ) with 22 human and 22 swine fecal pools .
three grams of feces from each pool were homogenized in phosphate - buffered saline and centrifuged for 1 hour at 4c .
rna was extracted by using the qiaamp viral rna mini kit ( qiagen , hilden , germany ) .
rt - pcr was performed in reduced reaction volumes of 25 l instead of 50 l ( 10 ) . for human pools
positive for hev rna , pcr was conducted with individual fecal samples that had been used in the pool . for phylogenetic analysis ,
internal primer sequences were used to amplify isolates of human and swine hev . the 348-nt sequence in open reading frame 2 of hev isolates was analyzed and compared with corresponding regions of other known human and swine hev strains available in genbank .
identification code , and genbank accession numbers of nucleotide sequences of the hev strains used in the phylogenetic and sequence analyses are japan , jjt - kan ( ab091394 ) ;
japan , jsn - sap - fho2c ( ab200239 ) ; japan , jsn - sap ( ab091395 ) ; japan , jkk - sap ( ab074917 ) ; people s republic of china , swdq ( dq279091 ) ; japan , jra1 ( ap003430 ) ; japan , heji4 ( ab080575 ) ; united states , avian - hev ( ef206691 ) ; japan , swj85 ( ab248521 ) ; people s republic of china , swch31 ( dq450072 ) ; japan , swj124 ( ab248522 ) ; india , ind - sw01 ( ay723745 ) ; japan , he - ja37 ( ab220978 ) ; japan , he - ja041911 ( ab248520 ) ; japan , jmng - oki02c ( ab236320 ) ; japan , he - ja41 ( ab220979 ) ; japan , swj131 ( ab097811 ) ; india , yam67 ( af459438 ) ; india , hyderabad ( af076239 ) ; and mexico , mexican strain ( m74506 ) .
a total of 15 ( 6.3% ) of 236 serum samples were positive for hev by igg elisa ( table ) .
the prevalence of igg against hev ( 7% ) was higher in persons in bartolo than in persons in casas viejas ( 4.7% ) ( p = 0.5 ) .
seroprevalence did not show a linear trend associated with age ; the highest seroprevalence was in found for persons 4150 years of age in both communities ( median age of 15 hev seropositive persons 45 years , range 287 years ) .
no sex - related differences in seroprevalence were observed in these communities ( male participants 47% , female participants 53% ) . figure .
phylogenetic tree with alignments of 348-bp open reading frame 2 sequences from human and swine samples of hepatitis e virus ( hev ) , bartolo and casas viejas , bolivia , compared with sequences of various hev isolates .
the tree was constructed by using the neighbor - joining method and evaluated by using the interior branch test method with mega5 software ( www.megasoftware.net ) .
percentage of bootstrap support is shown by values at the branch nodes of the tree . only nodes with a bootstrap value >
60% are labeled ; these values are the result of resampling the data 1,000 times .
hev - rna was detected in 5 ( 22.7% ) of 22 human fecal pools .
all 31 fecal samples in the 5 hev - positive pools were evaluated for hev rna .
hev rna was detected in 7 ( 31.8% ) of 22 swine fecal pools ( 6 [ 46% ] in bartolo and 1 [ 11% ] in casas viejas ) .
fecal samples from all 4 persons positive for hev by pcr were negative for igm and igg against hev by elisa .
phylogenetic analysis was performed on 11 amplification products obtained from 4 human and 7 swine fecal samples .
swine hev sequences were closely related to human hev sequences ( 76% nt and 92% aa homologies ) , and all belonged to hev genotype 3 .
the phylogenetic tree produced from alignment of the 348-nt open reading frame 2 sequences is shown in the figure .
in a survey performed in 1997 in southeastern bolivia , we found a seroprevalence of 7% for antibodies against hev ( 9 ) , a relatively high seroprevalence among young adults , and a low seroprevalence among children .
this study , conducted 9 years later in the same area , showed a similar seroprevalence ( 6% ) and age - dependent distribution of antibodies against hev and identified hev rna in fecal samples from human and swine populations .
sequence comparisons and phylogenetic analyses showed that swine hev strains were closely related to human strains ; all belonged to genotype 3 .
the high degree of nucleotide sequence homology observed suggests that swine could also be a major source of hev in the area of our study , but we are uncertain whether these findings can be extrapolated to other areas of bolivia .
absence of clinical signs in the swine studied is not an unexpected finding because swine naturally infected with hev are usually asymptomatic ( 13 ) . with regard to humans , no history of jaundice in seropositive persons was reported .
the 4 persons with positive hev rna results by rt - pcr but negative igm and igg results by elisas were asymptomatic at sample collection and had no signs or symptoms of hepatitis 3 months after testing .
this finding could be attributed to early infection , transient intestinal virus passage , or low accuracy of assays used ( 14 ) .
apparent limited illness associated with hev infection in humans may be caused by attenuated virulence of genotype 3 strains ( 15 ) .
additional studies are needed to define illness associated with hev infection in humans and determine whether hev infection is present in other animal species , particularly rodents , and their role in transmitting this virus ( 13 ) . | we determined the seroprevalence of hepatitis e virus ( hev ) in persons in 2 rural communities in southeastern bolivia and the presence of hev in human and swine fecal samples .
hev seroprevalence was 6.3% , and hev genotype 3 strains with high sequence homology were detected . |
Authorities in Florida released surveillance video today that, they say, shows a Minnesota grandmother wanted in two killings smiling and chatting up one of her alleged victims in a bar.
Lee County Sheriffs Office
Sgt. Anita Iriarte of the Lee County Sheriff's Office in Florida told ABC News the footage from the Smokin' Oyster Brewery showed suspect Lois Riess, 56, wearing a light-blue shirt and with white-gray hair, talking to Pamela Hutchinson.
Hutchinson, 59, was found fatally shot at her motel April 9, according to the Lee County Sheriff's Office. Her cash, credit cards, identification and white Acura had been stolen, police said. Police said the video was taken on April 5, 2018, at 5:40 p.m. in Fort Myers.
Police also said surveillance images appeared to show Riess leaving the motel.
Lee County Sheriffs Office
"Our suspect is absolutely armed and dangerous. ... She may look like anyone's grandmother or mother but behind that smile is a cold-blooded murderer," Lee County Undersheriff Carmine Marceno told ABC affiliate WZVN-TV.
KAAL
This weekend, authorities kicked off a cross-country manhunt for Riess of Blooming Prairie, Minnesota, whom they suspect of also shooting her husband, David, dead at their Minnesota home March 23 and then taking off in their car.
Marceno said Riess "loves casinos" and has a "gambling problem."
Police said that after she allegedly killed her husband, Riess made a stop at an Iowa casino. Then the trail went cold for two weeks. She then made her way to Fort Myers, Florida, where, police said, she befriended Hutchinson.
Hutchinson looked like Riess, police said, and they allege Riess' mode of operation was to befriend women before stealing their identity. Police in Fort Myers Beach, Florida, identified Riess as a suspect in Hutchinson's death.
Lee County Sheriffs Office
Police said Riess allegedly drove Hutchinson's car to Corpus Christi, Texas, where it was last spotted. Marceno said she may be in Mexico.
"Our main fear is once her resources, once she diminishes all her resources, that she will be desperate and she will commit another act of violence," he said. "We don't want any more acts of violence or God forbid murder. ... She's on the run and we need to do everything we can to bring her to justice."
Riess has three adult children and is a grandmother as well, according to Dodge County Sheriff Scott Rose. She has no criminal record, according to authorities. She is now wanted for murder, grand theft auto and identity theft.
ABC News' Amanda Maile contributed to this report. ||||| Video (00:07) : Lois Riess, 56, is shown patronizing the Smokin' Oyster Brewery in Fort Myers about 5:40 p.m. on April 5, just days before sheriff's deputies believe she killed and stole the identity of a woman who has a similar appearance.
The snippet of surveillance video is only seven seconds long. Yet in that brief span, it captures a "coldblooded killer" wooing a new friend who had only a short time to live.
Taken at a happy hour on April 5 at the Smokin' Oyster Brewery in Fort Myers, Fla., the video shows Lois Riess, of Blooming Prairie, Minn., talking to a woman police later identified as 59-year-old Pamela Hutchinson.
Riess appears charming and animated, tossing her silver hair as she leans in and smiles and chats with her bar mate. Four days later, Hutchinson would be found shot to death in her rented condo in Fort Myers Beach.
Authorities believe Riess, who fled Minnesota in late March after allegedly shooting and killing her husband, David, targeted Hutchinson because the two women looked alike, then stole her identity after killing her. "The suspect Riess … is on the loose and running," Lee County Undersheriff Carmine Marceno said Monday night. "We have a huge hunt with the U.S. marshals."
Riess, Marceno added, "could look like anybody's mother or grandmother. She smiles, yet she is a coldblooded killer. She's killed two people and she's still on the run."
As the hunt for Riess entered its fourth week Monday, new information about her past surfaced in court records in Minnesota that showed she had been accused of taking more than $78,000 from her disabled sister and spending it on herself, including thousands of dollars at casinos.
Recent photos of Lois Riess, 56, of Blooming Prairie, Minn. Believed to be in Texas, she is now in the deaths of her husband and a Florida woman.
According to the records:
Riess was appointed in 2012 as guardian and conservator for her older sister, Kimberly Sanchez, now 62. Legal documents said that Sanchez suffers from bipolar disorder and clinical depression, as well as Parkinson's disease, and has the cognitive level of a 10-year-old.
A routine annual audit in 2015 found supposed payments, gifts and loans from Sanchez's accounts that had no documentation to support the transactions. One payment of $14,000 supposedly was made to William Witte, the sisters' father — but he was dead.
Other payments totaling $15,000 were made to other relatives of Riess, again without supporting documentation. Riess also paid more than $40,000 to herself from her sister's assets, court records show.
In September 2015, Minnesota Prairie County Alliance, a nonprofit service organization, sought to have Riess terminated as her sister's guardian and conservator.
"I received a report that Lois Riess transfers funds from the guardianship account for Kimberly Sanchez to Lois Riess' own account," an affidavit said. "Lois Riess then withdraws the funds at the local casino."
In February 2016, Riess was removed as her sister's guardian and conservator. She did not contest her removal. That same month, the newly appointed guardian and conservator asked the court to order Riess to repay more than $78,000 to her sister's account.
There is no record that Riess was ever ordered to repay the money or that she was charged with a crime in the case. Officials of the new guardian and conservator, Alternative Resolutions Inc., declined to comment Monday.
Florida authorities said late last week that they believed Riess most recently was in the Corpus Christi area in Texas, possibly driving a car she stole from Hutchinson, whose body was found April 9.
Marceno said Hutchinson's white 2005 Acura TL with Florida license plate Y37TAA had been spotted in Louisiana and around Corpus Christi in the days after Hutchinson's body was found.
In recent days, however, the search for Riess has gone cold. Marceno said Monday that she will eventually run out of resources and fears that, in desperation, she could kill again. Riess is considered to be armed and dangerous, he said.
Hutchinson's relatives, meanwhile, said it is no surprise that Hutchinson, who was "outgoing" and "welcoming," would have struck up a conversation with a total stranger like Riess.
"She was very kind and sweet, everybody was a friend of hers," said Daniele Watts Jeffreys, a cousin from Richmond, Va.
Hutchinson, of Bradenton, Fla., was a former used-car salesperson in Virginia before she relocated to Florida. "You'd want to buy from her because she'd never cheat you," Jeffreys said. Hutchinson was divorced and didn't have many immediate family members. Her mother, who "was the world to her," died in 2013, Jeffreys said. After that, Hutchinson was constantly reaching out to other relatives to stay in touch and check in whether by phone, text message or social media, Jeffreys said.
Last Monday, after relatives were unable to reach her, authorities found Hutchinson's body inside the condo she rented in Fort Myers Beach, where she had gone to scatter ashes of another relative. She had been shot in the heart, Jeffreys said.
"It was just evil," Jeffreys said.
In this video image, Lois Riess, right, talked to Pamela Hutchinson. Days later, Hutchinson was shot dead.
Riess is suspected of killing her husband in late March at their home outside Blooming Prairie, a town of about 2,000 people 85 miles south of the Twin Cities. Police say the same gun was used in both slayings. Authorities also have said they suspect that after David Riess was killed, his wife transferred nearly $10,000 from his business account into his personal account and then forged his signature on three checks to herself for $11,000. She then fled the state, stopping at an Iowa casino on her way to Florida. Authorities were tipped off, but arrived too late to catch her.
Riess' whereabouts remained a mystery until last week, when she became a suspect in Hutchinson's murder after authorities in Florida found a white 2005 Cadillac Escalade that Riess was believed to have been driving after her husband's death.
Investigators said that after Riess befriended and killed Hutchinson, she stole her credit cards, cash and car. Photos showed Riess at Hutchinson's condo.
Late last week, Florida authorities filed murder, grand theft of a motor vehicle and grand theft and criminal use of personal identification charges against Riess. She also faces second-degree murder charges in Dodge County, Minnesota, where her husband's body was found March 23.
"I hope we bring this to closure soon," Marceno said Monday. "As quick and as safe as possible." | – "She may look like anyone's grandmother or mother but behind that smile is a cold-blooded murderer." So says Undersheriff Carmine Marceno of the Lee County Sheriff's Office in Florida of Lois Riess, the 56-year-old who is accused of murdering her husband in Blooming Prairie, Minn., last month and then traveling to Fort Myers, Fla. There, police believe she killed Pamela Hutchinson, who bore a resemblance to her, then took off with her identification. Now, ABC News reports Florida officials have released surveillance footage that apparently shows Riess cheerfully talking to Hutchinson, 59, at the Smokin' Oyster Brewery during happy hour on April 5. The Star Tribune reports the video is just seven seconds long, but shows Riess "wooing a new friend who had only a short time to live." Hutchinson was found dead with a gunshot wound to the heart on April 9. Though ABC News notes Riess had no prior criminal record, the Star Tribune reports it has emerged via court records that Riess was accused of siphoning more than $78,000 from her sister, who is disabled, during the 2012 to 2016 period that Riess served as her guardian and conservator. As for Riess' current whereabouts, police say Hutchinson's white 2005 Acura TL with Florida license plate Y37TAA was seen in Corpus Christi, Texas, in the wake of Hutchinson's death, but the trail has since gone cold. Marceno says it's possible Riess is now in Mexico and says "our main fear is ... she will commit another act of violence." Authorities caution she is armed and dangerous. |
the emergence of cementless fixation of hip prosthesis was partially based on the early failure of cement fixation , with radiographic loosening upward of 3040% at 10 years , namely in younger and more active patients .
, lord total hip artroplasty ( tha ) was composed by cementless cobalt chromium implants with a fully porous coated stem and a threaded cup ( fig .
the stem was relatively long coated with a sintered bead porous ingrowth / ongrowth surface , similar to the surface of some corals ( madreporic ) , to provide osseous anchorage .
initial femoral stem fixation depended on a fit in the tight trochanteric and in the diaphyseal area of the femur .
lord tha has been used rather extensively for the treatment of the hip osteoarthritis , namely in younger patients . at 1988 ,
lord reports favorable results , an experience over ten years in a series of 2688 personal cases .
most authors confirmed the excellent survival rate of the femoral component at long - term follow - up , and the poor results associated to the threaded acetabular cup , , .
lord tha was abandoned at 1987 in our orthopedic department , due to the high failure rate of the threaded cup by aseptic loosening .
studies of cementless stems with a minimum follow - up exceeding 20 years are uncommon .
the purpose of this paper is to show the excellent outcome of a lord femoral stem at the 31-year follow - up , implanted for the treatment of end - stage hip osteoarthritis .
a 24-year - old woman , an active clothing store worker , underwent a total hip arthroplasty due to advanced dysplastic osteoarthritis of the left hip .
the postoperative course was uneventful and she recovered promptly and had free of pain until 1996 . in 1995 , at the 12-years follow - up , she was observed in our orthopedics department due to severe groin pain , resistant to analgaesic medication , needing two forearm crutches to walk .
the hip radiographic studies were consistent with aseptic loosening of the acetabular component and a surgical intervention was proposed .
surgery was performed via the posterior approach , the loosening cup was removed and an acetabular metallic support ring with a cemented polyethylene cup were implanted .
the associated acetabular bone loss was reconstructed with morsellized cancellous bone allografts , by the impacting technique .
no complications were reported in the perioperative course or during the hospitalization period . at 2 month
postoperatively the patient was clinically able to walk without external support . at 9 years after the revision of the acetabular cup , the clinical and radiological results were very favorable .
patient was free of pain , hip radiograph showed signs of stress shielding in the proximal femur , with no functional repercussion .
2 ) . in the last clinical and radiological controls , at 19 years after revision surgery , the patient was asymptomatic , the hip mobility was normal , and with no limitations on her social and professional life .
hip radiographic study showed a stable seating of the acetabular component and signs of stress shielding of the proximal femur .
however , the femoral stem continued stable , with no measurable subsidence or radiolucent lines around the stem ( fig .
it was also possible to see signs of wear of the polyethylene cup , evidenced by a superior displacement of the metallic femoral head from the center of the acetabular cup .
the importance of the present report is that it shows the excellent clinical and radiological outcomes of an extensively porous - coated femoral stem at the 31-years follow - up .
several reports have presented a high clinical success rate with the fully - porous - coated lord femoral stem in both primary and revision cases .
grant in a study of one hundred and two patients ( 116 hips ) with a mean age of sixty - two years at the time of the index arthroplasty , reported excellent survival rate after 17.5 years of follow - up .
this type of porous coated of the femoral stem has introduced the new clinical problems of thigh pain and osteoporosis due to stress shielding of the proximal femur .
showed that large and extensively coated stems were associated with an increase in bone resorption and osteolysis .
proximal stress protection due to distal fixation has been regarded as a major problem with fully - coated stems .
in addition , others problems could also be observed including , fractures of the femoral stem or surgical difficulties to extract the stem in cases of deep sepsis or aseptic loosening .
in contrast the uncoated smooth threaded cup of lord has demonstrated poor fixation , early migration rate , resulting in reported high revision rates .
our case confirmed this findings , the aseptic loosening of the cup was seen at the 12-year follow - up .
then , the cup was removed and an acetabular metallic support ring with a cemented polyethylene cup were implanted .
the femoral stem was maintained confirmed by a solid fixation in the hip radiographic studies and there was neither stem subsidence nor distal bone density .
nonetheless is evident that bone of femoral calcar was resorbed and a moderate osteopenia and osteolysis were presented in the proximal femur , caused partly by stress shielding and partly by biological reaction to polyethylene wear debris . a pathologic fracture of the greater trochanter due to osteolysis can occur .
contrariwise , we consider that there is a very low risk of stem fatigue fracture .
the metal ring can be optimally adapted to the shape of the acetabulum since the polyethylene cup is anchored using cement and , thus , may be freely positioned .
favorable results were described using metal rings in congenital dysplasia of the hip , and in complex primary or revision hip arthroplasty .
, , at follow - up period of 19 years , the anteroposterior total hip arthroplasty radiograph showed a stable acetabular component with wear of the polyethylene cup that can contribute , in association with stress shielding , to the moderate periprosthetic osteolysis in the trochanteric femoral region .
the wear debris is an inevitable problem common to all hip endoprostheses . during the last clinical and radiological examinations , the patient presented a stable and asymptomatic hip and expressed high satisfaction with the surgery result .
the femoral stem presented an excellent fixation to the bone at follow - up period of 31 years . nowadays , like in the past , the acetabular side is the weak point in the hip prosthesis .
a good knowledge of the various implants available for surgical application is essential to aid surgeon choosing a proper total hip prosthesis for each patient .
despite lord total hip prosthesis has been discontinued , we believe that many femoral stems will continue to show mechanical stability for a long time after acetabular component revision , similarly to the present report .
it is important to emphasize that the patient is 55-years - old . to our knowledge
, there are no previous reports concerning results of the lord femoral stem with more than 26-year s follow - up .
written informed consent was obtained from the patient for publication of this case report and any accompanying images .
a copy of the written consent is available for review by the editor - in - chief of this journal upon request .
all authors contributed to the writing and collection of data , and they have participated in the surgery . | highlightslord tha was discontinued due to high revision rates of the smooth threaded acetabular component and negative effects of stress shielding in the proximal femur.nevertheless , the madreporic femoral stem continues to demonstrate favorable long - term results , showing a stable fixation to the femoral bone . |
Actress Lena Dunham says that in recent months she underwent a total hysterectomy in an attempt to finally end her years-long battle with chronic pain stemming from endometriosis.
A total hysterectomy involves the surgical removal of a woman’s cervix and uterus.
In an essay featured in the March 2018 issue of Vogue, Lena reveals that, after the procedure, she awoke to learn her reproductive organs were even more mangled than she had known. “In addition to endometrial disease,” wrote Lena, 31, “an odd hump-like protrusion and a septum running down the middle, I have retrograde bleeding, a.k.a. my period running in reverse so that my stomach is full of blood. My ovary has settled in on the muscles around the sacral nerves in my back that allow us to walk. Let’s please not even talk about my uterine lining. The only beautiful detail is that the organ—which is meant to be shaped like a light bulb—was shaped like a heart.”
Lena says her decision to undergo the elective surgery was a tough one, following “years of complex surgeries measuring in the double digits” and even alternative treatments like “pelvic floor therapy, massage therapy, pain therapy, color therapy, acupuncture,” and yoga.
Lena has been hospitalized at least three times in less than a year for endometriosis. Last April, she underwent surgery to free her ovaries from her rectal wall. Afterward, Lena declared she was endometriosis-free. But, sadly, on May 1, during her appearance at the Met Gala in NYC, she was rushed to a local hospital for complications. Days later, Lena canceled her nationwide “Lenny IRL” tour, telling fans that she was, “in the greatest amount of physical pain that I have ever experienced" after doctors discovered more endometriosis during subsequent surgery.
With her hysterectomy now behind her, hopefully, the worst is over for Lena. The former Girls star recently announced that she'd return to HBO with a new series, Camping. But perhaps she'll soon share even happier news: Lena reveals she’s determined to have children and is already exploring her options.
“I may have felt choiceless before, but I know I have choices now,” she writes. “Soon I’ll start exploring whether my ovaries, which remain someplace inside me in that vast cavern of organs and scar tissue, have eggs. Adoption is a thrilling truth I’ll pursue with all my might.” ||||| Lena Dunham has taken a major step in her journey with endometriosis.
The Girls star reveals in the March 2018 issue of Vogue that she underwent a total hysterectomy to remove her uterus and cervix, according to the Endometriosis Foundation of America. Dunham pens an essay detailing her decision after "years of complex surgeries measuring in the double digits" and unsuccessful attempts to treat the painful disorder with "pelvic floor therapy, massage therapy, pain therapy, color therapy [and] acupuncture."
Unfortunately, doctors found Dunham's health issues were much more serious than she initially thought.
"In addition to endometrial disease," the 31-year-old shares, "an odd hump-like protrusion and a septum running down the middle, I have retrograde bleeding, a.k.a. my period running in reverse so that my stomach is full of blood." | – Lena Dunham has undergone a total hysterectomy after years of chronic pain caused by endometriosis, which is caused by tissue from the uterus lining growing outside the organ. The Endometriosis Foundation of America says the Girls star, who had the operation to remove her uterus and cervix in recent months, writes about her health issues in an essay in the March issue of Vogue. "In addition to endometrial disease, an odd hump-like protrusion and a septum running down the middle, I have retrograde bleeding, aka my period running in reverse so that my stomach is full of blood," she writes. "My ovary has settled in on the muscles around the sacral nerves in my back that allow us to walk." She says she was declared endometriosis-free after an earlier surgery, but then the condition returned and she was in more pain than ever. "Let's please not even talk about my uterine lining," the 31-year-old writes. "The only beautiful detail is that the organ—which is meant to be shaped like a lightbulb—was shaped like a heart." She says she made the tough decision to have the surgery after "years of complex surgeries measuring in the double digits" and treatments including pelvic floor therapy, massage therapy, acupuncture, and yoga. Dunham is now infertile, but she says she still hopes to have children and is looking at her options, E! Online reports. "Soon I'll start exploring whether my ovaries, which remain someplace inside me in that vast cavern of organs and scar tissue, have eggs," she writes. "Adoption is a thrilling truth I'll pursue with all my might." |
it has the advantage of using small incisions to obtain good - quality visualization and access to the abdominal cavity .
compared with open appendectomy ( oa ) , la is associated with a decreased likelihood of superficial wound infection , decreased need for postoperative analgesics , quicker return to preoperative functional status , and improved cosmetic results .
although these outcomes are appropriate measures for younger patients , their relevance as measures of quality of care and patient safety in the elderly remains undefined .
numerous factors , including the us baby boom , better health coverage , and longer life expectancy , have led to an increase in the elderly population .
about 1 in 8 americans were elderly in 1994 ( defined as age 65 years ) , but about 1 in 5 will be elderly by the year 2030 .
the basis of these trends an aging population and a relatively high lifetime prevalence of appendectomy the prevalence of appendectomies in the elderly is increasing .
elderly surgery patients tend to have increased comorbidities , less physiologic reserve , and an altered nutritional status and show increased postoperative morbidity and mortality rates compared with younger adults .
reported complication rates after oa in the elderly range from 12% to 74% ; the mortality rate is as high as 14% . in the groundbreaking report to err
is human : building a safer health system , the institute of medicine observed that medical errors occurring in contemporary health care systems result primarily from problems inherent within organizations and processes rather than individuals .
patient safety indicators ( psis ) , designed as robust and accessible standardized process measures of patient safety events , are useful metrics of preventable medical errors that have been broadly applied and validated .
although prior studies have suggested that la is associated with improved outcomes in elderly patients compared with oa , comprehensive patient safety analyses , using validated , process - driven measures , have yet to be performed .
safety analyses incorporating validated patient safety outcomes would potentially inform the selection of operative approaches for appendectomy in the elderly .
therefore we compared the prevalence of adverse patient safety events occurring in la cases and oa cases in a national database over a 12-year period .
we analyzed the association of perioperative adverse patient safety events occurring in la cases and oa cases in the elderly .
data on inpatient procedures and adverse events were obtained from the healthcare cost and utilization project nationwide inpatient sample ( nis ) produced by the us agency for healthcare research and quality ( ahrq ) .
the nis represents the largest hospital inpatient dataset in the united states and consists of a 20% sample of inpatient discharges from 40 states and 1044 hospitals .
it contains deidentified patient , physician , and hospital clinical data with safeguards to protect privacy and is compiled from 7 to 12 million hospital stays each year .
the nis is a unique database that provides information on a variety of patient groups , regardless of payer , including persons covered by medicare , medicaid , and private insurance , as well as uninsured persons .
all discharges with a principal diagnosis of acute appendicitis identified through international classification of diseases , ninth revision , clinical modification codes were evaluated .
all identified patients from 1998 to 2009 were included in the analysis and divided into laparoscopy and open based on document procedure codes .
developed by the ahrq , psis are metrics of adverse outcomes ( table 1 ) that provide hospital- and national - level safety performance measures with greater specificity than other methods while avoiding the problems of reporting bias .
psis include the following : development of anesthetic complications , pneumothorax , hemorrhage / hematoma , decubitus ulcer , venous thrombosis / pulmonary embolism , hip fracture , postoperative physiologic and metabolic derangements , postoperative respiratory failure , sepsis , and accidental puncture or laceration during a procedure .
accidental punctures or lacerations include injuries to the surrounding organs including the bowel or other solid organ injuries and represent a wide spectrum of injury from minor to severe .
us agency for healthcare research and quality psis dvt = deep venous thrombosis ; pe = pulmonary embolism .
the primary outcome variable was the occurrence of any psi , a robust screening measure for identifying general systems problems that merit further examination .
the primary outcome variable was operation type ( la vs oa ) , with adjustment for known covariates .
covariates included in the analysis were age , sex , race ( white , african american , or other ) , ruptured appendix / abscess of appendix , income ( < $ 45 000 or $45 000 ) , insurance ( private , medicare , medicaid , or other ) , hospital type ( teaching or nonteaching ) , and hospital location ( rural or urban ) ; in addition , we included year ( 19982009 ) as a covariate to address evolving indications for , and collective expertise with , la . associated comorbidities were controlled for by use of the charlson index ( 02 or 3 ) .
independent univariate analyses were performed assessing secondary outcomes defined as individual ahrq psi events ( table 1 ) , including deaths in low - mortality diagnosis - related groups
an indicator for identifying in - hospital deaths occurring in patients unlikely to die during hospitalization .
a cost analysis of the median and quartile range of total hospital charges adjusted for inflation was investigated as a secondary outcome measure .
statistical analysis was performed with stata software , version 11.2 se ( stata corp lp , college station , texas ) .
univariate independent t tests were used for comparisons of quantitative variables ; fisher exact and tests were used to assess differences in the categorical variables . adjusted odds ratios for multiple logistic regression models
we analyzed the association of perioperative adverse patient safety events occurring in la cases and oa cases in the elderly .
data on inpatient procedures and adverse events were obtained from the healthcare cost and utilization project nationwide inpatient sample ( nis ) produced by the us agency for healthcare research and quality ( ahrq ) .
the nis represents the largest hospital inpatient dataset in the united states and consists of a 20% sample of inpatient discharges from 40 states and 1044 hospitals .
it contains deidentified patient , physician , and hospital clinical data with safeguards to protect privacy and is compiled from 7 to 12 million hospital stays each year .
the nis is a unique database that provides information on a variety of patient groups , regardless of payer , including persons covered by medicare , medicaid , and private insurance , as well as uninsured persons .
all discharges with a principal diagnosis of acute appendicitis identified through international classification of diseases , ninth revision , clinical modification codes were evaluated .
all identified patients from 1998 to 2009 were included in the analysis and divided into laparoscopy and open based on document procedure codes .
developed by the ahrq , psis are metrics of adverse outcomes ( table 1 ) that provide hospital- and national - level safety performance measures with greater specificity than other methods while avoiding the problems of reporting bias .
psis include the following : development of anesthetic complications , pneumothorax , hemorrhage / hematoma , decubitus ulcer , venous thrombosis / pulmonary embolism , hip fracture , postoperative physiologic and metabolic derangements , postoperative respiratory failure , sepsis , and accidental puncture or laceration during a procedure .
accidental punctures or lacerations include injuries to the surrounding organs including the bowel or other solid organ injuries and represent a wide spectrum of injury from minor to severe .
us agency for healthcare research and quality psis dvt = deep venous thrombosis ; pe = pulmonary embolism .
the primary outcome variable was the occurrence of any psi , a robust screening measure for identifying general systems problems that merit further examination .
the primary outcome variable was operation type ( la vs oa ) , with adjustment for known covariates .
covariates included in the analysis were age , sex , race ( white , african american , or other ) , ruptured appendix / abscess of appendix , income ( < $ 45 000 or $45 000 ) , insurance ( private , medicare , medicaid , or other ) , hospital type ( teaching or nonteaching ) , and hospital location ( rural or urban ) ; in addition , we included year ( 19982009 ) as a covariate to address evolving indications for , and collective expertise with , la . associated comorbidities were controlled for by use of the charlson index ( 02 or 3 ) .
independent univariate analyses were performed assessing secondary outcomes defined as individual ahrq psi events ( table 1 ) , including deaths in low - mortality diagnosis - related groups an indicator for identifying in - hospital deaths occurring in patients unlikely to die during hospitalization .
a cost analysis of the median and quartile range of total hospital charges adjusted for inflation was investigated as a secondary outcome measure .
statistical analysis was performed with stata software , version 11.2 se ( stata corp lp , college station , texas ) .
univariate independent t tests were used for comparisons of quantitative variables ; fisher exact and tests were used to assess differences in the categorical variables . adjusted odds ratios for multiple logistic regression models
from 1998 to 2009 , 257 484 appendectomies were performed for acute appendicitis in adults aged 65 years in the nis . of those ,
170 276 ( 66% ) were oas and 87 209 ( 34% ) were las .
the annual prevalence of la in the elderly increased from 14.4% in 1998 to 56.3% in 2009 . in 2008
the number of appendectomies performed laparoscopically exceeded the number performed in an open manner for the first time ( figures 1 and 2 ) .
appendectomy by year ( nis , age 65 years , 19982009 ) . proportion appendectomy performed laparoscopically by year ( nis , age 65 years , 19982009 ) .
elderly patients undergoing la were significantly younger , were more likely to be white , had lower charlson comorbidity scores , were more likely to undergo surgery in urban hospitals , and were less likely to have a ruptured appendix ; they were also marginally significantly more likely to have private insurance and undergo surgery at nonteaching hospitals ( table 2 ) .
compared with oa , la was associated with a decreased los ; fewer total psi events ; a decreased total mortality rate ; and a lower likelihood of failure to rescue , iatrogenic pneumothorax , infections due to medical care , postoperative respiratory failure , and postoperative pulmonary embolism or deep venous thrombosis ; as well as fewer accidental punctures or lacerations ( table 3 ) .
dvt = deep venous thrombosis ; na = not applicable ; pe = pulmonary embolism . on multivariate analysis ,
la was associated with a 32% reduction in the probability of any psi ( table 4 ) .
a subgroup analysis holding each independent control fixed was performed as a measure of model sensitivity .
la was associated with a decreased odds ratio for psi events for each subgroup included in the analysis , except medicare versus private insurance patients because of unavoidable collinearity when limiting the analysis to age 65 years .
from 1998 to 2009 , 257 484 appendectomies were performed for acute appendicitis in adults aged 65 years in the nis . of those ,
170 276 ( 66% ) were oas and 87 209 ( 34% ) were las .
the annual prevalence of la in the elderly increased from 14.4% in 1998 to 56.3% in 2009 . in 2008
the number of appendectomies performed laparoscopically exceeded the number performed in an open manner for the first time ( figures 1 and 2 ) .
appendectomy by year ( nis , age 65 years , 19982009 ) . proportion appendectomy performed laparoscopically by year ( nis , age 65 years , 19982009 ) .
elderly patients undergoing la were significantly younger , were more likely to be white , had lower charlson comorbidity scores , were more likely to undergo surgery in urban hospitals , and were less likely to have a ruptured appendix ; they were also marginally significantly more likely to have private insurance and undergo surgery at nonteaching hospitals ( table 2 ) .
compared with oa , la was associated with a decreased los ; fewer total psi events ; a decreased total mortality rate ; and a lower likelihood of failure to rescue , iatrogenic pneumothorax , infections due to medical care , postoperative respiratory failure , and postoperative pulmonary embolism or deep venous thrombosis ; as well as fewer accidental punctures or lacerations ( table 3 ) .
dvt = deep venous thrombosis ; na = not applicable ; pe = pulmonary embolism . on multivariate analysis ,
la was associated with a 32% reduction in the probability of any psi ( table 4 ) .
a subgroup analysis holding each independent control fixed was performed as a measure of model sensitivity .
la was associated with a decreased odds ratio for psi events for each subgroup included in the analysis , except medicare versus private insurance patients because of unavoidable collinearity when limiting the analysis to age 65 years .
to our knowledge , this is the first study in the united states to investigate perioperative outcomes of la in the elderly using validated patient safety measures in a national population . with 257 484 patients ,
it is also to our knowledge the largest analytic sample for population - level analyses of appendectomy .
we observed a 33% ( odds ratio , 0.677 ) decreased probability of patient safety events occurring in la cases compared with oa cases as measured by psis .
notably , this observation was independent of appendiceal rupture and comorbidity status and occurred during a period of rapid uptake of la by practicing surgeons .
our results thus suggest that use of la results in substantially enhanced perioperative patient safety as compared with oa .
this study addresses comparative patient safety analyses in the development of new technology and surgical practices .
although laparoscopic surgery has been shown to offer superior surgical outcomes for most abdominal surgical procedures , there is limited evidence on surgical outcomes with regard to patient safety , especially in the elderly population .
existing evidence suggests that la is as effective as oa with a decreased likelihood of superficial wound infection , a decreased need for postoperative analgesics , and a quicker return to preoperative functional status .
substantially less research , however , has focused on the elderly population ; moreover , although these outcomes may be appropriate measures for younger patients , additional comparative measures are necessary to ensure patient safety in the context of novel surgical techniques and assess quality - improvement efforts .
because psis measure preventable medical injuries , they are useful metrics for assessing the safety of surgical innovations in populations .
it is unclear why oa was associated with an increased risk of preventable medical injuries in elderly patients in the nis .
however , because most of the specific psis associated with oa are associated with postoperative morbidity including iatrogenic pneumothorax , postoperative respiratory failure , and postoperative deep venous thrombosis
it is possible that the longer inpatient convalescence of oa contributed to a greater risk of injury .
our results are consistent with most prior studies of la in the elderly , which involved smaller analytic cohorts and focused on patient - driven measures rather than process - driven measures .
a review of the national surgical quality improvement project database showed that oa yielded higher rates of both major and minor postoperative complications than the laparoscopic cases ( p < .0001 ) in the elderly both overall and before discharge .
multivariate analysis showed no association between operative approach and major complications , as well as a reduced risk of minor complications with laparoscopy and a shorter hospital stay than with oa .
another report compared la and oa in terms of los , charges , complications , discharge location , and mortality rate in elderly patients treated for appendicitis in north carolina over a 6-year period .
they found that la was associated with reductions in the mortality rate ( 0.38% vs 2.08% , p = .007 ) , complication rate ( 16.3% vs 20.8% , p = .01 ) , and los ( 4.64 days vs 7.29 days , p = .0001 ) and an increase in the proportion of routine discharges to home ( 91.4% vs 78.9% , p = .0001 ) when compared with oa .
similarly , a relatively small case series ( n = 150 ) observed that la patients had shorter hospital stays ( measured in days ) and lower rates of postoperative ventilator dependence than oa patients , whereas a population - based study in taiwan concluded that patients aged older than 65 years benefited from la with respect to los . in contrast , in a retrospective review of patients who underwent la comparing those aged 60 years with those aged < 60 years , complicated appendicitis and conversions were more frequent in the elderly patients , resulting in prolonged operative times and longer hospital stays .
moreover , the overall complication rate was statistically equivalent between the groups , as were the prevalence rates of infectious or surgical - site complications .
it is possible , however , that the mean age of patients undergoing la increased during the period of study as surgeons became more likely over time to offer la to older patients .
we therefore corrected for evolving indications for la by including year as a covariate in the regression modeling to reduce potential bias .
in addition , the difference in age between the open and laparoscopy groups , though statistically significant , was quite modest : < 1 year separated groups , which was likely clinically insignificant ( table 2 )
. the notable strengths of our study include the large size of the analytic cohort and models that adjusted for comorbidity status , appendiceal rupture , and appendiceal abscess clinical variables that could potentially bias the selection of surgical techniques for individual patients .
first , intent - to - treat analysis was not possible because data regarding conversion of laparoscopic cases to open cases were not available .
second , patient safety events occurring after hospital discharge could not be measured , nor could the duration of symptoms before hospital admission .
third , despite inclusion of multiple covariates in the regression analyses , the potential existed for residual confounding by complicated appendicitis , which occurred more often among oa patients . finally , it is important to note that , although psis identify potential systems errors , they do not provide detailed root - cause analyses .
root - cause analyses are best performed through in - depth reviews of clinical records .
la is associated with substantially enhanced perioperative patient safety compared with oa in the elderly .
the data also suggest that the diffusion of la into clinical practice is not associated with an increased risk of adverse safety events . | background and objectives : this study describes perioperative patient safety outcomes comparing laparoscopic appendectomy with open appendectomy in the elderly population ( defined as age 65 years ) during the diffusion of laparoscopic appendectomy into widespread clinical practice.methods:we performed a cross - sectional analysis of patients undergoing open or laparoscopic appendectomy in the us nationwide inpatient sample , a 20% sample of inpatient discharges from 1056 hospitals , from 1998 to 2009 , and used weighted sampling to estimate national trends .
multivariate logistic regression modeling was used to examine the association of laparoscopy with perioperative outcomes.results:patients who met the inclusion criteria totaled 257 484 .
of these , 87 209 ( 34% ) underwent laparoscopic appendectomy .
these patients were younger ( p < .001 ) ; had lower charlson comorbidity scores ( p < .001 ) ; were more likely to be white ( p < .001 ) , to be privately insured ( p = .005 ) , and to undergo surgery in urban hospitals (
p < .001 ) ; and were less likely to have appendiceal rupture ( p < .001 ) .
laparoscopic appendectomy was associated with a decreased length of stay ( 4.44 days vs 7.86 days , p < .001 ) , fewer total patient safety indicator events ( 1.8% vs 3.5% , p <
.001 ) , and a decreased mortality rate ( 0.9% vs 2.8% , p < .001 ) . on multivariate analyses , we observed a 32% ( odds ratio , 0.68 ) decreased probability of patient safety events occurring in laparoscopic appendectomy cases versus open appendectomy cases as measured by patient safety indicators.conclusion:the data suggest that laparoscopic appendectomy is associated with improved clinical outcomes in the elderly and that diffusion of laparoscopic appendectomy is not associated with adverse patient safety events in this population . |
alzheimer 's disease ( ad ) is a heterogeneous and progressive neurodegenerative disorder representing the most common cause of dementia in the elderly
. the disease results from a complex interaction between predisposing genes , biochemical variables , and environmental factors .
the variant e4 of the apoe gene ( apoe4 ) , for example , is widely recognized to contribute to the risk of developing the more common late - onset ad , while mutations in the genes that encode presenilin 1 and 2 and the amyloid precursor protein ( app ) are known to be causative factors of a small percentage of familial and early - onset ad cases .
there is also total agreement on the existence of a link between ad and oxidative stress phenomena triggered by transition metals .
however , these phenomena have been generally viewed as originating locally within specific brain areas , and autonomously , that is , independently of systemic influences . in this frame , authors have reported enhanced iron concentrations in ad brains , both in autopsy brain tissues and in cerebrospinal fluid ( csf ) [ 3 , 4 ] , especially in the basal ganglia ( in vivo : [ 5 , 6 ] autopsy : ) , in the hippocampus ( in vivo : [ 6 , 8 ] ; autopsy : [ 9 , 10 ] ) , neocortex ( autopsy : [ 7 , 9 , 11 ] ) , and around the senile plaques of amyloid beta ( a ) or the neurofibrillary tangles commonly found in ad brains [ 1215 ] .
authors have also reported altered local concentrations of specific proteins regulating iron levels , such as ceruloplasmin [ 1618 ] , transferrin [ 7 , 19 ] , and ferritin .
recently , a wider and somewhat complementary view has emerged suggesting a relationship of ad with systemic , rather than autonomous , changes of metal metabolisms .
some pilot studies based on this view have focused primarily on the genes of hemochromatosis ( hfe ) and of transferrin , since they play a key role in iron homeostasis , but investigations on circulating markers of iron metabolism are still relatively scanty . in the present study , we focused on this aspect and studied systemic variations of markers of iron metabolism , such as serum iron , ceruloplasmin , transferrin , transferrin saturation , and ratio of ceruloplasmin to transferrin ( cp / tf ) , in a sample of ad patients and in one of healthy elderly subjects .
forty - nine ad patients ( mean age 75.6 ) and 46 cognitively normal individuals ( mean age 71.2 ) were included in the study ( see table 1 ) .
the two samples were slightly different in sex and age ; consequently , when appropriate , all statistical analyses were adjusted for these two confounders .
the ad patient sample consisted of individuals with a clinical diagnosis of probable ad based on nincds - adrda criteria and with a mini - mental state examination ( mmse ) score of 25 or less .
all ad patients underwent neurologic , neuroimaging ( magnetic resonance imaging : mri or computed tomography : ct ) , and neuropsychological evaluation , as well as routine laboratory tests .
average disease duration ( from symptom onset ) was 27 ( range 696 ) months .
the control sample consisted of elderly volunteers with no clinical evidence of neurologic or psychiatric disease .
twelve ad patients had either poor quality mri or reasons not to take it ( e.g. , metal prostheses ) . in these cases ,
all controls underwent a neurologic examination and mmse , but only 12 consented to mri .
criteria for exclusion of both patients and controls were conditions known to affect metal metabolism and biological variables of oxidative stress , for example , diabetes mellitus , inflammatory diseases , hodgkin 's disease , recent history of heart or respiratory failure , chronic liver or renal failure , malignant tumors , and alcohol abuse , assessed by tests including complete blood count , erythrocyte sedimentation rate ( esr ) , cholesterol , triglycerides , ferritin and fibrinogen levels , serum protein electrophoresis , renal function ( creatinine , blood urea nitrogen ) , fasting glucose , electrolytes , vitamin b12 , and folic acid and uric acid levels ; thyroid function tests ( thyroxin , triiodothyronine , and thyrotropin levels ) ; liver enzymes ( transaminases ) , cardiac enzymes ( creatine phosphokinase , lactate dehydrogenase ) , bilirubin levels ; serology for syphilis , and urine analysis .
patients and controls with abnormal values of thyroid , liver , kidney , and cardiac functions were also excluded from the study .
the study was approved by the local irb , and all participants or legal guardians gave written , informed consent .
sera from fasting blood samples were collected in the morning and rapidly stored at 80c .
methods for measuring biological variables of metals and oxidative stress are described in detail elsewhere .
briefly , hydroperoxide content was assessed by d - roms test ( diacron , italy ) and expressed in arbitrary units ( u.carr ) , 1 u.carr corresponding to 0.08 mg/100 ml of hydrogen peroxide .
transferrin and ceruloplasmin were measured by immunoturbidimetric assays ( roche , diagnostic , germany ) utilizing a goat antihuman transferrin antibody in tris / hcl buffer and a rabbit antihuman ceruloplasmin antibody in phosphate buffer and iron using ferene [ 20 , 21 ] .
all biochemical measures were automated on a hitachi 912 analyser ( roche diagnostics ) and performed in duplicate .
the imaging protocol consisted of axial t2 w double spin echo ( se ) sequences and t1 w se images in axial , coronal , and sagittal planes , with 5 mm slice thickness and intersection gap = 0.5 mm .
mr images were evaluated by two experienced neuroradiologists , blind to the patients ' diagnoses and laboratory results , with an agreement of about 95% .
atrophy and white matter lesions were graded following standardized visual rating scales on plain mri [ 2527 ] .
the degree of medial temporal lobe atrophy ( mta ) was evaluated with a ranking procedure and validated by linear measurements of the medial temporal lobe including the hippocampal formation and surrounding spaces occupied by csf , following standardized criteria ( five - point rating scale of mta ) .
generalized brain atrophy ( ventricular and sulcal atrophy ) was rated as present ( = 1 ) or absent ( = 0 ; global atrophy ) .
the visual rating scale of white matter changes included the anatomical distribution as well as the severity of the lesions .
based on anatomical distribution , a distinction was made between areas of periventricular hyperintensities ( pvh ) ( caps and rims ) and deeper hyperintensities ( including frontal , parieto - occipital , and temporal white matter hyperintensities : dwmh , basal ganglia hyperintensities : bgh , and infratentorial hyperintensities : ith ) .
large vessel cortical infarcts in the anterior , posterior , and medial cerebral artery were also evaluated .
presence of mass lesions and lobar hemorrhages was an exclusion criteria from the study [ 27 , 28 ] .
the carotid and vertebral arteries were studied by means of color - coded duplex ultrasonography ( 7.5 mhz probe ; acuson , aspen , usa ) according to standardized criteria .
particular attention was paid to detecting both presence and degree of stenosis of atherosclerotic plaques in the carotid and vertebral arteries .
the intima and media thickness ( imt ) from the distal portion of the cca was investigated in detail in each patient according to previous studies .
intracranial vessels were also examined by transcranial doppler ( tcd multidop t tcd - dwl , germany ) , according to previously described methods .
ad and controls were described in terms of main demographic , genetic , and cognitive characteristics and statistically compared with either t- or -square tests .
correlation analyses between biological variables , mmse scores , mri atrophy , and vascular measurements ( spearman 's rho ) were performed .
the t test was used when the homogeneity of variances could be assumed . when the variances were statistically heterogeneous , the games - howell procedure was applied .
no differences for fasting glucose , vitamin b12 , folic acid and uric acid levels , esr , bilirubin levels , cholesterol , triglycerides , albumin , complete blood count , and hypertension were detected between the two groups ( data not shown ) .
none among the biological variables under study correlated with age , with the exception of ceruloplasmin ( r = 0.355 , p = .01 ) and peroxides ( r = 0.215 , p = .039 ) , which both increased with age ( these two variables were corrected for the age effect before entering the statistical analyses ) .
table 2 reports the values of serum iron , ceruloplasmin , transferrin , transferrin saturation , and cp / tf in ad patients and controls .
transferrin saturation ( p = .033 ) and cp / tf ( p < .001 ) resulted increased in ad patients compared to controls ( table 2 ) .
cp / tf correlated positively with peroxide levels ( r = 0.560 , p < .001 ) and negatively with serum iron concentrations ( r = 0.417 , p < .001 ) .
elevated values of ceruloplasmin , peroxides , and cp / tf inversely correlated with mmse scores ( table 3 ) .
correlation analysis from the doppler examination revealed that no ad patient had abnormal flow velocity in the cerebral arteries examined by duplex sonography and tcd ( results not shown ) .
moreover , none of the biochemical variables assayed correlated with ultrasound indicators of cerebrovascular burden , namely , presence of carotid plaque or stenosis , except for the imt values that correlated with apoe 4 genotype ( spearman rho = 0.36 ; p < .01 ) confirming what was previously reported .
analyses of mri data showed that presence of supratentorial atrophy , ( enlarged sulci , widened lateral , and third ventricles ) , and atrophy of the temporal lobes ( reduction in hippocampal volume ) , was prominent in ad subjects , while control subjects ' values were consistent with those found in normal aging . among mri measurements and serum oxidative - iron markers values
, there was a negative correlation between isolated medial temporal atrophy ( mta ) and serum iron and a positive one between cp / tf and mta ( table 3 ) .
white matter changes and deep - seated ischemic changes did not correlate with any metal marker as well as peroxides .
the results of our comparison between ad patients and healthy controls show that major markers of circulating iron status , such as ceruloplasmin , cp / tf , transferrin saturation , and peroxides levels , are abnormal in ad patients .
this finding demonstrates that systemic alterations of iron metabolism accompany the disease and indicate that the role attributed by existing literature to local iron accumulations in brain areas critical for ad should be rather viewed in the frame of a wider systemic alteration . in this scenario ,
as we did previously with stroke patients , we used the cp / tf ratio to represent the functionality of one of these systems , the cp - tf system , which is otherwise difficult to monitor biochemically . in the cp - tf system , ceruloplasmin catalyzes the oxidation of ferrous iron ( fe ) into ferric iron ( fe ) , by way of the following chemical reaction :
( 1)4 fe2++4 h++o24 fe3++2 h2o .
this is generally viewed as a good reaction both because its byproduct is innocuous water and because , once transformed into fe , iron binds to transferrin by which it is transported to cells .
ceruloplasmin - catalyzed iron oxidation and removal from circulation by transferrin is a very important process since it reduces the amount of fe available for participation in fenton 's reactions , whose byproducts are instead extremely vicious
. in fact , ferrous iron can also convert hydrogen peroxide into the highly reactive radicals oh and ooh :
( 2)fe2++h2o2fe3++oh+ oh
which , in turn , proceeds as follows :
( 3)fe3++h2o2fe2++ooh+ h+ .
in other words ,
if it were not oxidized and removed by the coordinated ceruloplasmin and transferrin actions , iron would cyclically produce highly reactive radicals , which the circulating blood would then distribute all over the organism . nonetheless , it is important to keep in mind that if , on one hand , this mechanism avoids or reduces production of lethal oxidative species in general circulation and allows the vital transport of iron to cells , on the other hand , when iron moves into the cells , as it could be the case for neurons , it can still cause brain damage if a concomitant neuronal iron defective efflux does occur .
evidence of a defective iron efflux from neurons , linked to app , was reported in several studies on cell cultures and app knockout mice ( app/ ) , in which app expression is experimentally suppressed [ 34 , 35 ] .
the ablation of app , which is normally expressed both in the brain and in a limited number of nonneural tissues as platelets , liver , kidney , and heart [ 34 , 35 ] , produces metal disbalance in these organs and tissues .
in particular , some authors demonstrated an increase of copper concentrations in the liver ( 80% ) and in the brain ( 40% ) in app/ mice .
other authors demonstrated that app ablation causes an iron increase of 26% in the brain , 31% in the liver , and 15% in the kidney .
all together , these studies demonstrate that app plays a role in copper and iron mobilization , indicating that its abnormalities in ad have either a systemic effect on those metals ' homeostasis or a local effect on neuronal metal efflux .
our current results of increased brain atrophy ( mta scores ) in ad patients are in support to this concept , as mta scores associate to either decreasing levels of serum iron or increased values of cp / tf ratios .
both these results appear coherent with the picture of an abnormal activation of the cp - tf system in ad , the subtraction of iron from general circulation , and its probable internalization into neural cells .
this eventually could cause neuronal death via generation of oxidative stress in a transition metal(s ) reactions . finally , in the same direction go also our results on mmse scores , which worsen with increasing cp / tf ratios .
ceruloplasmin increase and transferrin decrease concentrations were identified in diverse pathological conditions as an important defense mechanism reflecting the body 's resistance to an oxidant insult .
this is the case , for example , in severe preeclampsia , where women have high levels of lipid peroxidation and serum ceruloplasmin and low levels of transferrin [ 37 , 38 ] , in acute stroke , where the cp / tf correlates with the severity of the clinical status , or in experimental hypercholesterolemia .
ceruloplasmin increase and transferrin decrease concentrations are also reported as a sign of inflammation in a number of conditions spanning from cardiac to psychiatric .
in fact , these proteins are acute phase reactants ( positive and negative , resp . ) , produced by the liver together with several other proteins .
another protein affecting iron homeostasis is hfe , a membrane protein which controls iron absorption by regulating the affinity of transferrin receptors on cell membrane .
specific mutations of the hfe gene cause hemochromatosis , that is , an increased absorption of dietary iron and its consequent over deposition in tissues and organs .
recently , a number of studies have shown various relationships between ad and mutations of the hfe , as well as the transferrin , genes but reported data are controversial and far from univocal interpretation [ 4146 ] . in a very recent study of ours
, we found that the synergy of altered markers of iron status ( iron levels , transferrin , transferrin saturation , ferritin , and cp / tf ratio ) and mutations of the hfe gene can increase the probability of developing ad ( submitted ) .
overall , cp - tf antioxidant system represents the serum capacity to sequester exchangeable metals ( copper , iron ) which make a labile metal pool prone to partake in reactions generating oxidative damage [ 47 , 48 ] .
previous studies of altered levels of this labile metal pool in ad , especially referred to a serum increase of free copper , that is , the quantity of copper which is not bound to ceruloplasmin , sustain this concept [ 49 , 50 ] .
support to this notion comes also from a study of our laboratory showing lower cortical responses in depressed patients who presented lower transferrin and higher free copper serum levels . as a whole
the data presented are in agreement with the past key works by both loeffer 's and castellani 's groups , who reported higher ceruloplasmin levels in brain areas critical for ad
. however , the relationship between systemic processes and local effects in the brain is the main focus of our laboratory 's work in progress .
| the link between iron and alzheimer 's disease ( ad ) has been mainly investigated with a focus on the local accumulation of this metal in specific areas of the brain that are critical for ad . in the present study , we have instead looked at systemic variations of markers of iron metabolism .
we measured serum levels of iron , ceruloplasmin , and transferrin and calculated the transferrin saturation and the ceruloplasmin to transferrin ratio ( cp / tf ) .
cp / tf and transferrin saturation increased in ad patients .
cp / tf ratios also correlated positively with peroxide levels and negatively with serum iron concentrations .
elevated values of ceruloplasmin , peroxides , and cp / tf inversely correlated with mmse scores .
isolated medial temporal lobe atrophy positively correlated with cp / tf and negatively with serum iron .
all these findings indicate that the local iron accumulation found in brain areas critical for ad should be viewed in the frame of iron systemic alterations . |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Gas Price Relief for Consumers Act
of 2008''.
TITLE I--AMENDMENT TO SHERMAN ACT
SEC. 101. SHORT TITLE.
This title may be cited as the ``No Oil Producing and Exporting
Cartels Act of 2008'' or ``NOPEC''.
SEC. 102. SHERMAN ACT.
The Sherman Act (15 U.S.C. 1 et seq.) is amended by adding after
section 7 the following:
``Sec. 7A. (a) It shall be illegal and a violation of this Act for
any foreign state, or any instrumentality or agent of any foreign
state, to act collectively or in combination with any other foreign
state, any instrumentality or agent of any other foreign state, or any
other person, whether by cartel or any other association or form of
cooperation or joint action--
``(1) to limit the production or distribution of oil,
natural gas, or any other petroleum product;
``(2) to set or maintain the price of oil, natural gas, or
any petroleum product; or
``(3) to otherwise take any action in restraint of trade
for oil, natural gas, or any petroleum product;
when such action, combination, or collective action has a direct,
substantial, and reasonably foreseeable effect on the market, supply,
price, or distribution of oil, natural gas, or other petroleum product
in the United States.
``(b) A foreign state engaged in conduct in violation of subsection
(a) shall not be immune under the doctrine of sovereign immunity from
the jurisdiction or judgments of the courts of the United States in any
action brought to enforce this section.
``(c) No court of the United States shall decline, based on the act
of state doctrine, to make a determination on the merits in an action
brought under this section.
``(d) The Attorney General of the United States may bring an action
to enforce this section in any district court of the United States as
provided under the antitrust laws.''.
SEC. 103. SOVEREIGN IMMUNITY.
Section 1605(a) of title 28, United States Code, is amended--
(1) in paragraph (6) by striking ``or'' after the
semicolon;
(2) in paragraph (7) by striking the period and inserting
``; or''; and
(3) by adding at the end the following:
``(8) in which the action is brought under section 7A of
the Sherman Act.''.
TITLE II--CREATION OF DEPARTMENT OF JUSTICE PETROLEUM INDUSTRY
ANTITRUST TASK FORCE
SEC. 201. ESTABLISHMENT OF DEPARTMENT OF JUSTICE PETROLEUM INDUSTRY
ANTITRUST TASK FORCE.
(a) Establishment of Task Force.--The Attorney General shall
establish in the Department of Justice a Petroleum Industry Antitrust
Task Force (in this title referred to as the ``Task Force'').
(b) Responsibilities of Task Force.--The Task Force shall have the
responsibility for--
(1) developing, coordinating, and facilitating the
implementation of the investigative and enforcement policies of
the Department of Justice related to petroleum industry
antitrust issues under Federal law,
(2) consulting with, and requesting assistance from, other
Federal entities as may be appropriate, and
(3) preparing and submitting to the Congress an annual
report that--
(A) describes all investigatory and enforcement
efforts of the Department of Justice related to
petroleum industry antitrust issues, and
(B) addresses the issues described in subsection
(c).
(c) Issues To Be Examined by Task Force.--The Task Force shall
examine all issues related to the application of Federal antitrust laws
to the market for petroleum and petroleum products, including the
following:
(1) The existence and effects of any price gouging in sales
of gasoline.
(2) The existence and effects of any international oil
cartels.
(3) The existence and effects of any collusive behavior in
controlling or restricting petroleum refinery capacity.
(4) The existence and effects of any anticompetitive price
discrimination by petroleum refiners or other wholesalers of
gasoline to retail sellers of gasoline.
(5) The existence and effects of any unilateral actions, by
refiners or other wholesalers of petroleum products, in the
nature of withholding supply or otherwise refusing to sell
petroleum products in order to inflate the price of such
products above competitive levels.
(6) The existence and effects of any anticompetitive
manipulation in futures markets or other trading exchanges
relating to petroleum or petroleum products.
(7) The existence and effects of any other anticompetitive
market manipulation activities involving petroleum or petroleum
products.
(8) Any other anticompetitive behavior that impacts the
price or supply of petroleum or petroleum products.
(9) The advisability of revising the merger guidelines to
appropriately take into account particular aspects of the
petroleum and petroleum products marketplace.
(10) The advisability of amending the antitrust laws in
light of any competitive problems in the petroleum and
petroleum products marketplace described in paragraphs (1)-(8)
that cannot currently be effectively addressed under such laws.
(d) Director of Task Force.--The Attorney General shall appoint a
director to head the Task Force.
(e) Initial Report.--The 1st report required by subsection (b)(2)
shall be submitted to the Congress not later than December 31, 2008.
TITLE III--STUDY BY THE GOVERNMENT ACCOUNTABILITY OFFICE
SEC. 301. STUDY BY THE GOVERNMENT ACCOUNTABILITY OFFICE.
(a) Study.--Not later than 180 days after the date of the enactment
of this Act, the Comptroller General of the United States shall conduct
a study evaluating the effects of mergers addressed in covered merger
consent decrees on competition in the markets involved, including the
effectiveness of divestitures required under those consent decrees in
preserving competition in those markets.
(b) Report.--Not later than one year after the date of the
enactment of this Act, the Comptroller General shall submit a report to
Congress and the Department of Justice regarding the findings of the
study conducted under subsection (b).
(c) Attorney General Consideration.--Upon receipt of the report
described in subsection (b), the Attorney General shall refer the
report to the Task Force established under section 201, which shall
consider whether any further enforcement action is warranted to protect
or restore competition in any market affected by a transaction to which
any covered merger consent decree relates.
(d) Definition.--In this section, the term ``covered merger consent
decree'' means a consent decree entered in the 10-year period ending on
the date of the enactment of this Act, in an enforcement action brought
under section 7 of the Clayton Act against a person engaged in the
business of exploring for, producing, refining, processing, storing,
distributing, or marketing petroleum or petroleum products.
Passed the House of Representatives May 20, 2008.
Attest:
LORRAINE C. MILLER,
Clerk. | Gas Price Relief for Consumers Act of 2008 - Title I: Amendment to Sherman Act - No Oil Producing and Exporting Cartels Act of 2008 or NOPEC - (Sec. 102) Amends the Sherman Act to make it illegal for any foreign state or instrumentality thereof to act collectively or in combination with any other foreign state or any other person, when such action has a direct, substantial, and reasonably foreseeable effect on the market, supply, price, or distribution of petroleum in the United States, to: (1) limit the production or distribution of oil, natural gas, or any other petroleum product (petroleum); (2) set or maintain the price of petroleum; or (3) otherwise take any action in restraint of trade for petroleum.
Denies a foreign state engaged in such conduct sovereign immunity from the jurisdiction or judgments of U.S. courts in any action brought to enforce this Act.
States that no U.S. court shall decline, based on the act of state doctrine, to make a determination on the merits in an action brought under this Act.
Authorizes the Attorney General to bring an action in U.S. district court to enforce this Act.
(Sec. 103) Makes an exception to the jurisdictional immunity of a foreign state in an action brought under this Act.
Title II: Creation of Department of Justice Petroleum Industry Antitrust Task Force - (Sec. 201) Directs the Attorney General to establish in the Department of Justice (DOJ) a Petroleum Industry Antitrust Task Force to: (1) develop, coordinate, and facilitate the implementation of DOJ investigative and enforcement policies related to petroleum industry antitrust issues under federal law; and (2) report annually to Congress on DOJ investigatory and enforcement efforts related to petroleum industry antitrust issues, and on issues related to the application of federal antitrust laws to the market for petroleum.
Title III: Study by the Government Accountability Office - (Sec. 301) Directs the Comptroller General to: (1) conduct a study evaluating the effects of mergers addressed in covered petroleum merger consent decrees on competition in the markets involved, including the effectiveness of divestitures required in such decrees in preserving competition in those markets; and (2) report study results to Congress and DOJ.
Directs the Attorney General to refer such report to the Task Force, which shall consider whether any further enforcement action is warranted to protect or restore competition in any market affected by a transaction to which any covered merger consent decree relates. |
investigations of sheath formation in front of a floating plate have hitherto been restricted to fluid studies on the ion time scale [ 1 ] . by contrast , the response of the plasma in the very early stages of sheath formation is not well known . in this paper , we present pic simulations of the plasma dynamics over just a few electron plasma periods after the beginning of the process .
these simulations have been performed by means of the bit1 code [ 2 ] , developed on the basis of the xpdp1 code from u. c. berkeley [ 3 ] .
a floating plate is placed in contact with a uniform , quasi - neutral plasma , which is assumed to be infinitely extended on one side . due to the higher thermal velocity of the electrons ,
the plate starts charging up negatively , so that electrons are gradually repelled , ions are attracted , and a positive - space - charge sheath begins to form .
an electron plasma wave is observed the properties of which strongly depend on the plasma characteristics ( electron and ion temperatures , plasma density , etc . ) .
our pic simulations are performed with different numerical set - ups and plasma characteristics .
a full set of simulation diagnostics is used to measure the properties of the electron waves .
we consider a one - dimensional system .
the planar conducting plate and the ( artificial ) right - hand boundary of the systems are placed at positions @xmath5 and @xmath6 , respectively .
the length @xmath7 is to be chosen large enough for this system to reasonably approximate a semi - infinite plasma ( @xmath8 , with @xmath9 the electron debye length ) . in order to have adequate resolution in space ,
the length of the grid cells has been selected as @xmath10 . at the initial time @xmath11 the electron and ion densities are equal @xmath12 , the distribution functions of both particle species are fully maxwellian , and the electric potential is zero @xmath13 everywhere in the system , including the plate surface . throughout the entire simulation , the following boundary conditions are applied to the particles : at the plate , all particles impinging are absorbed and no particles are injected into the plasma . at the right - hand boundary , on the other hand , all particles impinging are absorbed but new particles with half maxwellian distribution functions are injected at a constant rate .
the system is floating , i.e. , the sum of particle plus displacement currents equals zero . according to these conditions we observe the following behavior . in the unperturbed plasma region (
i.e. , for @xmath14 ) the electron velocity distribution function will not change appreciably ( so that @xmath15 ) , whereas at the plate it will acquire a cut - off form .
this is because the negative - velocity electrons are absorbed by the plate and charge it negatively ; during this process , the ions can be considered to be at rest . with increasing negative surface charge , the negative potential drop in the region close to
the plate becomes higher and more and more electrons are reflected towards the plasma . after some time this perturbation propagates into the system .
the shape of the distribution function essentially depends on the potential drop at the plate . due to the loss of particles by absorption at the plate ,
the total number of particles in the system is dropping all the time .
however , this aspect is not of great concern here because the total loss of particles during the entire simulation presented is negligible . in the following tables we present the parameters used for our simulation .
the ( electron and ion ) particle fluxes corresponding to the unperturbed plasma region are : @xmath16 these expressions are used to calculate the particle injection fluxes from the right - hand boundary .
* parameter * & * value * & * remarks * + @xmath17 & @xmath18 & + @xmath19 & @xmath20 & + @xmath21 & @xmath22 & at @xmath23 + @xmath24 & @xmath25 & + @xmath26 & @xmath27 & + @xmath28 & @xmath29 & + @xmath30 & @xmath31 & + @xmath32 & @xmath33 & electron plasma frequency + @xmath34 & @xmath35 & ion plasma frequency + @xmath36 & @xmath37 & proton mass + @xmath9 & @xmath38 & + * parameter * & * value * & * remarks * + @xmath39 & @xmath40 & grid - cell length @xmath41 + @xmath7 & @xmath42 & system lenght + @xmath43 & @xmath44 & plate aria + @xmath45 & @xmath46 & time step + @xmath47 & @xmath48 & total simulation time +
r0.5 figure [ pot_strat_sursa ] shows the potential profile close to the plate at @xmath49 s. the potential drop at the beginning of the sheath evolution is monotonic in space .
after quick acquisition of negative charge , the plate repels the electrons in the form of a pulse leaving behind a positive - space charge region . as a result ,
the potential close to the plate becomes slightly positive . in front of this region ,
the negative space charge produced by the primary - pulse electrons leads to a potential minimum ( `` virtual cathode '' ) , which gradually reflects more and more slower electrons back into the plasma .
these latter electrons spend a long time in the region of the virtual cathode and hence deepen its potential further . according to figures .
[ evol_rho ] and [ cimp_strat ] , this first potential perturbation ( consisting of a potential hill and a potential well ) propagates into the unperturbed plasma , with additional similar wave structures forming behind it .
r0.5 to verify that these waves are physical and not just due to numerical effects , we have performed other simulations with different parameters .
in particular , we concentrated on the electron temperature .
we know that the debye length is proportional to the square root of the electron temperature .
hence , if we increase the temperature by a factor of four , the debye length must increase by a factor of two .
since , in addition , there is a relation between the wavelength of the electron waves and the debye length , the variation of the electron temperature should also have an effect on the wavelength .
this is clearly illustrated in + figure [ comparare ] , where the wavelength is seen to increase with the square root of the electron temperature . and
@xmath50 _ , scaledwidth=70.0% ]
this work represents the beginning of a self - consistent kinetic study of sheath formation , taking into account both electron and ion dynamics . here , during the short simulation time considered , the ions are practically immobile , and only the electrons take part in the process . in the next step
, the effect of ion dynamics on sheath formation will be considered as well .
this work was supported by the austrian science fund ( fwf ) projects p15013-n08 and p16807-n08 , ceepus network a103 , and erasmus / socrates grant 2004 - 2005 .
* [ 1 ] * j.w .
cipolla , jr . , and m. b. silevitch , on the temporal development of a plasma sheath , j. plasma phys . 25 , 373 - 89 ( jun 1981 ) * [ 3 ] * j. p. verboncoeur , m. v. alves , v. vahedi , and c. k. birdsall , simultaneous potential and circuit solution for 1d bounded plasma particle simulation codes , j. comput .
104 ( 2 ) , 321 ( 1993 ) . abstract submittal form | the problem of sheath formation in front of a conductive planar plate inserted into the plasma is formulated .
initially , the plate is assumed to be neutral .
it is shown that the charging - up process of the plate is accompanied by the excitation of electron plasma waves . _
@xmath0 plasma physics department , faculty of physics , al .
i. cuza university , ro-700506 iasi , romania , + @xmath1j .
stefan institute , university of ljubljana , jamova 39 , slo-1000 ljubljana , slovenia , + @xmath2 association euratom - oaw , department of theoretical physics , university of innsbruck , a-6020 innsbruck , austria , + @xmath3 permanent address : institute of physics , georgian academy of sciences , 380077 tbilisi , georgia , + @xmath4association euratom - oaw , department of ion physics , university of innsbruck , a-6020 innsbruck , austria _ |
due to the growing demand of patients for esthetic restorations and the concern about
the possible adverse effects of the mercury released from amalgam , the search for direct
composite resins has increased considerably and their use in posterior teeth is now also
a routine in dental practice .
it has been demonstrated that the extent of polymerization of resin materials is
directly related to the quality of their physical , mechanical and biological
properties .
when a material is underpolymerized due to low light
intensity delivered from the curing unit or inadequate light exposure time , free resin
monomers that were not converted into a polymer network may remain in the deeper areas
of composite resin restorations and may be released from the material , contributing to
weaken the restoration and alter color stability .
unreacted monomers
located on the base of composite resin restorations can diffuse through the polymerized
bonding agent and dentinal tubules to reach the pulp tissue .
these resin components are cytotoxic and may cause local tissue irritation and pulpal
inflammation , especially
when applied in very deep cavities .
numerous factors may affect the polymerization of resin restorative materials , such as
the light intensity emitted by the curing units and the light - curing time , as well as
thickness of overlying restorative material , its composition and color .
the duration of light exposure is one of the most important variables
governing the polymerization of light - activated restorative composites .
it can be a
rate - limiting step in the polymerization process when using light - source intensities
greater than 280 mw / cm and when the incremental layer thickness does not
exceed 2 mm .
several methodologies have been proposed to evaluate the cytotoxicity of dental
materials and their components . for a long time , in vitro cell culture
experiments have been widely used .
although there is no
consensus in the literature regarding the most indicated cell type for these kind of
investigations , cells from the odontoblast - like mdpc-23 cell line ( mouse dental papillae
cells ) have been frequently used , mainly because of their odontoblast phenotype .
in addition , odontoblasts are the first
cell line to receive components released from restorative dental materials that are
capable of diffusing across dentinal tubules . the aim of this in vitro
study was to evaluate the influence of the curing time on the cytotoxicity of a
restorative composite resin on immortalized odontoblast - like mdpc-23 cells .
odontoblast - like cells ( mdpc-23 cells ) were cultured at 30x10/cm in complete
dulbecco 's modified eagle 's medium ( dmem ; sigma chemical co. , st .
louis , mo , usa )
supplemented with 10% fetal bovine serum ( gibco , grand island , ny , usa ) , with 100
iu / ml penicillin , 100 mg / ml streptomycin and 2 mm / l glutamine ( gibco ) .
the cells were
allowed to grow for 72 h in a humidified incubator at 37c with 5%
co2 and 95% air ( isotemp ; fisher scientific , pittsburgh , pa , usa ) .
forty experimental round - shaped composite resin ( organic matrix : bis - gma / tegdma ;
inorganic fillings : zirconia / silica- 66% of volume ) specimens ( 4 mm in diameter x 2
mm thick ) were prepared using a split stainless steel matrix with the same dimensions
( incombi ; indstria e comrcio de mquinas biagioni ltda . ,
araraquara , sp , brazil ) .
the specimens were distributed into four experimental groups
( n=10 ) according to the curing time used for composite resin photoactivation : group 1
( g1 ) - dark curing ; groups 2 , 3 and 4 ( g2 , g3 and g4 ) - the composite resin specimens
were light - cured for 20 , 40 and 60 s , respectively ; in g5 ( control group ) , 10 sterile
4-mm - diamater filter paper discs ( matheson scientific inc . , e&d 613 , mi , usa )
were soaked with 5 l phosphate buffered saline solution ( pbs ) . after the
insertion in the stainless - steel molds , the material was covered by a plastic strip
to avoid the oxygen inhibiting layer , and a standardized load ( 500 g ) was applied to
promote the overflow of material .
the selected specimens were light - activated at one
end with a halogen light - curing unit ( optilux 500 , demetron / kerr , danbury , ct , usa ) .
the light intensity was monitored with a radiometer ( optilux 500 , demetron / kerr ,
danbury , ct , usa , 410 mw / cm ) . in group 1 ,
the specimens were allowed to set in the dark for
15 min in an incubator at 37c with 100% humidity .
after light- or dark - curing of the material , the specimens were removed from the
molds and rinsed under agitation with pbs and dmem culture medium during 5 min each .
then , the round - shaped resin specimens were placed individually on the bottom of the
wells of sterile 24-well plates ( costar corp . , cambridge , ma , usa ) .
the specimens
were maintained in place under slight pressure , by means of a hand - made orthodontic
wire clasp in a shape of an inverted loop .
mdpc-23 cells were seeded at an initial
density of 30,000 cells / cm in each well containing 1 ml of complete dmem
supplemented with 10% fbs ( gibco , grand island , ny , usa ) , 100 iu / ml penicillin , 100
mg / ml streptomycin and 2 mm / l glutamine ( gibco ) .
the well - plates were maintained for
72 h in a humidified incubator ( isotemp ; fisher scientific ) at 37c with 5%
co2 and 95% air .
cell metabolic activity was evaluated by succinic dehydrogenase ( sdh ) activity , which
is a measure of the mitochondrial respiration of the cells . for this purpose ,
the
methyltetrazolium ( mtt ) assay was used . to assess the cell metabolism ,
the resin specimens were removed from 8 wells of each
group and the culture medium was replaced by 900 ml of dmem and 100 l of mtt
solution ( sigma chemical co. , usa ) ( 5 mg / ml pbs ) .
the cells were incubated at
37c for 4 hours with 5% co2 and 95% air .
thereafter , the culture
medium which had been mixed with the mtt solution was aspirated and replaced by 600
l of acid- isopropanol solution ( 100 l of 0.04 n hcl in isopropanol ) in each well
to dissolve the dark blue crystals formed in the presence of active mitochondria .
the
optical density of the solutions was determined by means of a spectrophotometer ( elx
800 - universal microplate reader ; bio - tek instrument , inc . ,
winooski , vt , usa ) ,
using a test wavelength of 570 nm .
detailed procedures for these measurements were
previously described by mosmann
( 1983 ) .
cell morphology was assessed in two specimens of each group , using a scanning
electron microscope ( jeol - jms - t33a scanning microscope ) . for such purpose ,
sterile
12-mm - diameter cover glasses ( fisher scientific ) were placed on the bottom of two
wells before placement of the resin specimens and seeding of the mdpc-23 cells
( 30,000 cells / cm ) .
after 72-h incubation , the resin specimens were
removed from the wells and the cells were fixed in 2.5% glutaraldehyde solutions for
24 h , post - fixed for 60 min in 1% osmium tetroxide , dehydrated in a series of
increasing ethanol concentrations , and were subjected to drying with the
hexamethyldisilazane solvent ( hmds ; acros organics , springfield , nj , usa ) .
finally ,
the cells were mounted on metallic stubs , sputter - coated with gold and had their
morphology examined with a scanning electron microscope ( jeol - jms - t33a , tokyo ,
japan ) .
both experiments ( cell metabolism assay and morphological analysis ) were performed in
triplicate to ensure the reproducibility . as
cell metabolism activity data had a non - normal distribution , the non - parametric
kruskal - wallis test was used for analysis of the variables material
and light - curing time , complemented by mann - whitney tests .
odontoblast - like cells ( mdpc-23 cells ) were cultured at 30x10/cm in complete
dulbecco 's modified eagle 's medium ( dmem ; sigma chemical co. , st .
louis , mo , usa )
supplemented with 10% fetal bovine serum ( gibco , grand island , ny , usa ) , with 100
iu / ml penicillin , 100 mg / ml streptomycin and 2 mm / l glutamine ( gibco ) .
the cells were
allowed to grow for 72 h in a humidified incubator at 37c with 5%
co2 and 95% air ( isotemp ; fisher scientific , pittsburgh , pa , usa ) .
forty experimental round - shaped composite resin ( organic matrix : bis - gma / tegdma ;
inorganic fillings : zirconia / silica- 66% of volume ) specimens ( 4 mm in diameter x 2
mm thick ) were prepared using a split stainless steel matrix with the same dimensions
( incombi ; indstria e comrcio de mquinas biagioni ltda . ,
araraquara , sp , brazil ) .
the specimens were distributed into four experimental groups
( n=10 ) according to the curing time used for composite resin photoactivation : group 1
( g1 ) - dark curing ; groups 2 , 3 and 4 ( g2 , g3 and g4 ) - the composite resin specimens
were light - cured for 20 , 40 and 60 s , respectively ; in g5 ( control group ) , 10 sterile
4-mm - diamater filter paper discs ( matheson scientific inc . ,
e&d 613 , mi , usa )
were soaked with 5 l phosphate buffered saline solution ( pbs ) .
after the
insertion in the stainless - steel molds , the material was covered by a plastic strip
to avoid the oxygen inhibiting layer , and a standardized load ( 500 g ) was applied to
promote the overflow of material .
the selected specimens were light - activated at one
end with a halogen light - curing unit ( optilux 500 , demetron / kerr , danbury , ct , usa ) .
the light intensity was monitored with a radiometer ( optilux 500 , demetron / kerr ,
danbury , ct , usa , 410 mw / cm ) . in group 1 ,
the specimens were allowed to set in the dark for
15 min in an incubator at 37c with 100% humidity .
after light- or dark - curing of the material , the specimens were removed from the
molds and rinsed under agitation with pbs and dmem culture medium during 5 min each .
then , the round - shaped resin specimens were placed individually on the bottom of the
wells of sterile 24-well plates ( costar corp . ,
the specimens
were maintained in place under slight pressure , by means of a hand - made orthodontic
wire clasp in a shape of an inverted loop .
mdpc-23 cells were seeded at an initial
density of 30,000 cells / cm in each well containing 1 ml of complete dmem
supplemented with 10% fbs ( gibco , grand island , ny , usa ) , 100 iu / ml penicillin , 100
mg / ml streptomycin and 2 mm / l glutamine ( gibco ) .
the well - plates were maintained for
72 h in a humidified incubator ( isotemp ; fisher scientific ) at 37c with 5%
co2 and 95% air .
cell metabolic activity was evaluated by succinic dehydrogenase ( sdh ) activity , which
is a measure of the mitochondrial respiration of the cells . for this purpose ,
the
methyltetrazolium ( mtt ) assay was used . to assess the cell metabolism ,
the resin specimens were removed from 8 wells of each
group and the culture medium was replaced by 900 ml of dmem and 100 l of mtt
solution ( sigma chemical co. , usa ) ( 5 mg / ml pbs ) .
the cells were incubated at
37c for 4 hours with 5% co2 and 95% air .
thereafter , the culture
medium which had been mixed with the mtt solution was aspirated and replaced by 600
l of acid- isopropanol solution ( 100 l of 0.04 n hcl in isopropanol ) in each well
to dissolve the dark blue crystals formed in the presence of active mitochondria .
the
optical density of the solutions was determined by means of a spectrophotometer ( elx
800 - universal microplate reader ; bio - tek instrument , inc . ,
winooski , vt , usa ) ,
using a test wavelength of 570 nm .
detailed procedures for these measurements were
previously described by mosmann
( 1983 ) .
cell morphology was assessed in two specimens of each group , using a scanning
electron microscope ( jeol - jms - t33a scanning microscope ) . for such purpose ,
sterile
12-mm - diameter cover glasses ( fisher scientific ) were placed on the bottom of two
wells before placement of the resin specimens and seeding of the mdpc-23 cells
( 30,000 cells / cm ) .
after 72-h incubation , the resin specimens were
removed from the wells and the cells were fixed in 2.5% glutaraldehyde solutions for
24 h , post - fixed for 60 min in 1% osmium tetroxide , dehydrated in a series of
increasing ethanol concentrations , and were subjected to drying with the
hexamethyldisilazane solvent ( hmds ; acros organics , springfield , nj , usa ) .
finally ,
the cells were mounted on metallic stubs , sputter - coated with gold and had their
morphology examined with a scanning electron microscope ( jeol - jms - t33a , tokyo ,
japan ) .
both experiments ( cell metabolism assay and morphological analysis ) were performed in
triplicate to ensure the reproducibility . as cell metabolism activity data had a non - normal distribution , the non - parametric
kruskal - wallis test was used for analysis of the variables material
and light - curing time , complemented by mann - whitney tests .
the results of cell metabolism after 72 h of direct contact of the composite resin
with the mdpc-23 cells are presented in table
1 .
sdh enzyme activity of the odontoblast - like cells ( mdpc-23 ) detected by the mtt
assay as a function of the curing time values represent median ( percentile 25-percentile 75 ) , optical density ( od ) .
medians followed by the same lowercase letters in the rows and uppercase
letters in the columns are statistically not different ( mann - whitney ,
p>0.05 ) there was statistically significant difference ( p<0.05 ) between the test material
( experimental composite resin ) and the negative control ( pbs ) , as well as between the
different light - curing times ( p<0.05 ) . regardless of the light - curing time , the
composite resin presented mild or no toxic effect to the mdpc-23 cells .
however , when
dark - curing was done , the direct contact with the material caused a reduction of
86.2% in cell metabolism , while the reduction seen for the other three curing times
was 13.3% for 20 s , 13.5% for 40 s and 0% for 60 s. g4 and g5 presented statistically similar values of mdpc-23 cell metabolic activity
( 0.451 and 0.421 , respectively ) ( p>0.05 ) , while the values for g2 ( 0.390 ) and g3
( 0.402 ) differed significantly ( p<0.05 ) from those of g1 ( 0.055 ) and g4
( 0.451 ) . in the negative control group ( g5 ) ,
the mdpc-23 cells that remained attached to the
glass substrate were organized in epithelioid nodules .
morphologically , the mdpc-23
cells were spindle - shaped and presented numerous cytoplasmic processes , which seemed
to be keeping the cells attached to the glass substrate ( figure 1 ) .
cells from the groups in which the composite resin was
light - activated for 40 s ( g3 ) and 60 s ( g4 ) exhibited similar morphological
characteristics ( figures 2a and 2b ) .
on the other hand , in g2 ( 20
s - light - activation ) , a small number of mdpc-23 cells remained adhered to the glass
substrate .
these cells were small - sized , round - shaped and presented few or no
cytoplasmic processes originating from their membrane ( figure 3a ) . in g1 ( dark - curing ) , extensive cell - free areas with a number
of globular structures suggestive of composite resin fragments were also observed
( figure 3b ) . negative control group ( pbs - g5 ) - presence of spindle - shaped cells organized in
dense nodules and long cytoplasmic processes ( original magnification :
x1,000 ) panel of sem micrographs representative of cell morphology .
a - group 3 ( 40 s ) ;
b - group 4 ( 60 s ) . presence of spindle - shaped cells organized in dense
nodules .
a - group 2 ( 20 s )
- presence of few small - sized and round - shaped cells with few cytoplasmic
processes ; b - group 1 ( dark - curing ) - presence of a small number of cells
adhered to the glass substrate and structures suggestive of rests of degraded
cell components .
the results of cell metabolism after 72 h of direct contact of the composite resin
with the mdpc-23 cells are presented in table
1 .
sdh enzyme activity of the odontoblast - like cells ( mdpc-23 ) detected by the mtt
assay as a function of the curing time values represent median ( percentile 25-percentile 75 ) , optical density ( od ) .
medians followed by the same lowercase letters in the rows and uppercase
letters in the columns are statistically not different ( mann - whitney ,
p>0.05 ) there was statistically significant difference ( p<0.05 ) between the test material
( experimental composite resin ) and the negative control ( pbs ) , as well as between the
different light - curing times ( p<0.05 ) . regardless of the light - curing time , the
composite resin presented mild or no toxic effect to the mdpc-23 cells .
however , when
dark - curing was done , the direct contact with the material caused a reduction of
86.2% in cell metabolism , while the reduction seen for the other three curing times
was 13.3% for 20 s , 13.5% for 40 s and 0% for 60 s. g4 and g5 presented statistically similar values of mdpc-23 cell metabolic activity
( 0.451 and 0.421 , respectively ) ( p>0.05 ) , while the values for g2 ( 0.390 ) and g3
( 0.402 ) differed significantly ( p<0.05 ) from those of g1 ( 0.055 ) and g4
( 0.451 ) .
in the negative control group ( g5 ) , the mdpc-23 cells that remained attached to the
glass substrate were organized in epithelioid nodules .
morphologically , the mdpc-23
cells were spindle - shaped and presented numerous cytoplasmic processes , which seemed
to be keeping the cells attached to the glass substrate ( figure 1 ) .
cells from the groups in which the composite resin was
light - activated for 40 s ( g3 ) and 60 s ( g4 ) exhibited similar morphological
characteristics ( figures 2a and 2b ) . on the other hand , in g2 ( 20
s - light - activation ) ,
these cells were small - sized , round - shaped and presented few or no
cytoplasmic processes originating from their membrane ( figure 3a ) . in g1 ( dark - curing ) , extensive cell - free areas with a number
of globular structures suggestive of composite resin fragments were also observed
( figure 3b ) . negative control group ( pbs - g5 ) - presence of spindle - shaped cells organized in
dense nodules and long cytoplasmic processes ( original magnification :
x1,000 ) panel of sem micrographs representative of cell morphology . a - group 3 ( 40 s ) ;
b - group 4 ( 60 s ) .
a - group 2 ( 20 s )
- presence of few small - sized and round - shaped cells with few cytoplasmic
processes ; b - group 1 ( dark - curing ) - presence of a small number of cells
adhered to the glass substrate and structures suggestive of rests of degraded
cell components .
several in vitro studies have used different cell types with
odontoblast phenotype to evaluate potential cytotoxic effects of dental materials and/or
their individual components . in the present study , immortalized odontoblast - like mdpc-23 cells were
used to evaluate the cytotoxic effect of an experimental resin composite because
odontoblasts are organized in a monolayer that underlies the pulp chamber , being
therefore the first cells to be damaged by potentially cytotoxic compounds released from
dental materials capable to diffuse through dentin into the pulp space . in this study ,
the direct contact of dark - cured composite resin specimens with
immortalized odontoblast - like mdpc-23 cells caused an intense toxic effect , as
demonstrated by an 86.2% reduction in cell metabolism .
on the other hand , the cytotoxic
effects of the composite resin decreased significantly when the material was
light - activated using the manufacturer 's recommended ( 40 s ) and a shorter ( 20 s )
light - exposure time with a reduction of 13.3% and 13.5% in cell metabolism ,
respectively .
( 2003 ) , who concluded that the composite resin
light - cured for 20 s was more cytotoxic to mdpc-23 cells than the experimental material
light - cured for 40 s , with a reduction in cell metabolism by 40.1% and 24.5% ,
respectively .
these different findings may be due to the fact that costa , et
al .
( 2003 ) maintained the
specimens immersed in pbs and dmem with consecutive changes in each solution at 5-min
intervals .
although the same procedure was performed , in the present study , the
specimens were maintained under continuous agitation during the entire experimental
period .
therefore , it may be speculated that most unreacted and highly toxic residual
monomers that remained on specimen surface were eliminated by the vigorous rinsing ,
producing low cytotoxic effects .
however , this supposition could only be confirmed by
qualitative and quantitative analyses by mass spectrometry of the experimental composite
resin components released in the pbs and dmem after rinsing . in the present study ,
a significant reduction in the cytotoxic effects occurred when the
composite resin was light - activated for 60 s ( g4 ) and the results were similar to those
of the control group ( g5 ) .
( 2003 ) suggested that the cytotoxicity of the dental materials is
inversely proportional to the light - curing time , which is in accordance with our results
when a 60 s exposure to the light source was used ( g4 ) .
( 1991 ) who
evaluated the cytotoxicity of three composite resins subjected to different light - curing
times ( 15 , 30 and 45 s ) and correlated the results with the monomer conversion rate .
the
longer the light - curing time , the higher the monomer conversion rate and consequently
the lower the cytotoxicity of each tested material .
it is known that composite resin polymerization occurs by the conversion of the monomer
molecules into a polymer network .
when the composite resin is underpolymerized , residual
monomers may be released from the material in contact with dentin moisture and reach the
pulp tissue causing severe damage associated to cell death . in the present study ,
the non - light - cured experimental
composite resin caused extremely severe cytotoxic effects to mdpc-23 cell line ,
confirming that the non - conversion of monomers into polymers result in high
cytotoxicity .
most of the few mdpc-23 cells that remained adhered to the glass substrate
were lost due to the direct effect of the material , which caused cell damage and death
by either a chemical action or induction of apoptosis .
these cells exhibited a small
size and round shape with few or no cytoplasmic processes ( figure 3b ) .
some factors , such as light intensity and light - curing time , are essential for the
polymerization of resin materials . however ,
when light
intensity is not the limiting factor , exposure time is essential to resin
polymerization . since light
intensity
was maintained about 460 mw / cm in the present study , it may be
suggested that shortening the light exposure time from 40 to 20 s did not influence
significantly on the cytotoxic effects of the tested composite resin .
however , such a
difference may be observed with thicker composite resin increments . in the sem analysis
,
it was observed that the shorter the light - curing time , the larger the number of
structures characterized as resin fragments on the glass substrate .
this finding
confirms that a shorter exposure to the light source results in a lower conversion of
monomers into polymers within the resin material core , leading to a greater
solubilization of the components in aqueous media .
the toxicity of resin materials has been attributed to their composition and processes that occur during their
polymerization , such as the release of toxic components and temperature change .
composite resins
present an organic matrix composed of resin monomers and a zirconium / silica inorganic
matrix ( nearly 70% by volume ) .
( 1999 ) identified in most composites the co - monomer tegdma
( triethyleneglycol - dimethacrylate ) as the main component released and a small amount of
the monomers bis - gma ( bisphenol - a - glycidyl - dimethacrylate ) and udma ( urethane
dimethacrylate ) , other co - monomers and additives .
these components may produce adverse
effects in the organism , allergic reactions , systemic toxicity , mutagenicity and
cytotoxicity .
the residual methacrylate monomers
released from underpolymerized resin materials are incorporated to the lipid bilayer of
the cell membrane , causing the solubilization of this structure .
this phenomenon is
responsible for cell death and may explain the role of resin monomers in the
cytotoxicity of composite resins .
the external application of heat on the dental tissues may cause pulp damage of
different severities , depending on the intensity and duration of the temperature
rise .
increase of the
temperature on tooth surface or even on the pulp tissue may occur during some operative
procedures such as cavity preparation with rotary instruments , laser irradiation or photoactivation of resin materials .
( 1995 ) have shown that resin - modified
glass ionomer cements and composite resins exhibited a rapid rise in temperature during
light - exposure and reached a peak value within a very short time .
after that , the
temperature decreased immediately on removal of the light source to that of the room
temperature .
the authors also reported that the longer irradiation times did not produce
significantly greater temperature rise , but they prolonged the period before the
temperature started to decline .
in the present study , the increase of temperature on the
composite resin did not influence on the cytotoxicity because , according to the employed
methodology , the time elapsed between light - activation of the specimens and their direct
contact with the mdpc-23 cells ( 15 min on average ) was sufficient to allow temperature
decrease .
a previous in vitro study investigating methods for evaluation of the
cytotoxic effects of dental materials to cell cultures has shown that the direct
cell / material contact simulates in an effective manner the in vivo
condition .
however , results of
laboratorial experiments can not be directly extrapolated to clinical conditions .
therefore , before dental materials can be recommended for clinical applications ,
in vitro and in vivo studies should be carried out
to offer clinicians and patients safety and efficacy data based on the balance among the
materials ' physical , mechanical , chemical and biological properties on the different
dental tissues .
the results obtained in the present in vitro
investigation suggest that any factor that limits or undermines the polymerization of
resin materials , such as low light intensity , short light - curing time , longer distance
between material surface and light source , may contribute to increase significantly
their cytotoxic effects to the pulp cells .
therefore , it is mandatory that the
manufacturers ' instructions of use are strictly followed regarding the adequate
photoactivation of resin materials , which is inversely related to cytotoxicity .
regardless of the light - activation time used in the present investigation , the
experimental composite resin presented mild to no toxic effects to the odontoblast - like
mdpc-23 cells .
however , intense cytotoxic effects occurred when the resin - based material
was not light - cured . | this in vitro study evaluated the cytotoxicity of an experimental
restorative composite resin subjected to different light - curing regimens.methodsforty round - shaped specimens were prepared and randomly assigned to four
experimental groups ( n=10 ) , as follows : in group 1 , no light - curing ; in groups 2 ,
3 and 4 , the composite resin specimens were light - cured for 20 , 40 or 60 s ,
respectively . in group 5 ,
filter paper discs soaked in 5 l pbs were used as
negative controls .
the resin specimens and paper discs were placed in wells of
24-well plates in which the odontoblast - like cells mdpc-23 ( 30,000
cells / cm2 ) were plated and incubated in a humidified incubator with
5% co2 and 95% air at 37c for 72 h. the cytotoxicity was
evaluated by the cell metabolism ( mtt assay ) and cell morphology ( sem ) .
the data
were analyzed statistically by kruskal - wallis and mann- whitney tests
( p<0.05).resultsin g1 , cell metabolism decreased by 86.2% , indicating a severe cytotoxicity of the
non - light - cured composite resin . on the other hand ,
cell metabolism decreased by
only 13.3% and 13.5% in g2 and g3 , respectively .
no cytotoxic effects were
observed in g4 and g5 . in g1 , only a few round - shaped cells with short processes
on their cytoplasmic membrane were observed . in the other experimental groups as
well as in control group ,
a number of spindle - shaped cells with long cytoplasmic
processes were found.conclusionregardless of the photoactivation time used in the present investigation , the
experimental composite resin presented mild to no toxic effects to the
odontoblast - like mdpc-23 cells .
however , intense cytotoxic effects occurred when
no light - curing was performed . |
infection of mice - swiss female mice , weighing approximately 20 g , infected with 200 10 s. mansoni cercariae ( le strain ) , by subcutaneous route , or 50 cercariae when mice were sacrificed 100 days after infection , were used in this study .
treatment of animals - oxamniquine , praziquantel and artesunate were administered in monotherapy or in association ( praziquantel and artesunate ) , always with single dose and by oral route .
the schedules utilised for treatments were as follows : oxamniquine - 200 mg / kg or 400 mg / kg weight in monotherapy , praziquantel - 400 mg / kg or 800 mg / kg in monotherapy or in association with 300 mg / kg or 600 mg / kg artesunate , which was also used in monotherapy with the same doses as the association .
the animals were treated 14 , 15 , 21 or 23 days post - infection and the perfusion of mice was performed five , 42 or 100 days after treatment for collection , counting and classification of worms .
evaluation of schistosomicidal activity - in order to evaluate the activity of drugs at the pre - patent ( pre - postural ) phase of infection , the animals were submitted to euthanasia by cervical fracture ( experimental groups and controls in all the schedules ) .
after that , the animals were submitted to perfusion of the mesenteric veins and liver , according to the technique prescribed by pellegrino and siqueira ( 1956 ) for worm recovery .
after perfusion of the portal system , the recovered immature worms were counted and classified using a stereomicroscope .
morphological criteria , based on the development of the digestive tract of the parasite after ingestion of blood , were used for its classification regarding its evolutive stage , constituting the schistogram ( barbosa et al .
1978 ) . for activity evaluation at the patent phase , perfusion of mesenteric veins and liver was performed aiming at recovering and counting adult worms ( pellegrino & siqueira 1956 ) .
the livers were crushed between slide and coverslip and observed under a stereomicroscope for counting of dead worms ; fragments from the distal portion of the small intestine , measuring approximately 1 cm , were compressed between two plastic slides and observed under optical microscope for detection of s. mansoni eggs at different evolutive stages ( pellegrino et al .
groups of untreated infected mice ( control of infection ) were kept in all the schedules and were submitted to the same procedure for treated animals , except treatment .
schistogram changes were observed taking into account differences in the average of recovered immature worms , at each evolutive stage after comparison to untreated control and percentage in reduction of recovered adult worms of treated groups in relation to untreated control .
the average of recovered worms , distribution of worms in the liver and mesentery , percentage of dead worms in the liver and of oogram changes were indicators of drug activity on the adult worm ( pellegrino & katz 1968 ) .
kruskal - wallis test , followed by dunn 's multiple comparison , were applied to non - parametric data , whereas pearson 's x test and anova , followed by tukey 's multiple comparisons , were applied to parametric data .
ethics - the guidelines of the ethical committee for the use of experimental animals of oswaldo cruz foundation were followed ( ceua l-018/09 ) .
.
table idistribution of young worms recovered from mice infected with 200 schistosoma mansoni cercariae treated with single dose by oral route as monotherapy and submitted to euthanasia ( treated and control groups ) five days after treatment
animals
( n ) distribution of schistosomules per evolutive stage
( % ) treatment schedule ( mg / kg ) treated after infection
( days ) treated examined mean of worm ( % reduction ) 1 2 3 4 5 6 ni oxamniquine 200 15 13 13 12.5 ( 57 )
0.5 12.2 36.8 50 0 0 0.5 artesunate 300 15 13 13 10.0 ( 65.6 )
3.8 8.5 10.8
57.7 2.3 0 16.9
praziquantel 400 15 13 13 16.5 ( 43.3 )
0.9 6 24.2 67.5 0.9 0 0.5 control - - 12 29.1 ( 0 ) 3.1 7.2 26.4 59 0.3 0 4 oxamniquine 200 23 13 12 37.0 ( 31.2 ) 0 0 0.7 14.6 37.8 46.8 0 artesunate 300 23 13 13 27.8 ( 48.3 )
0 0.3 0.3 13 31.6 54.8 0 praziquantel 400 23 13 13 42.7 ( 20.6 ) 0 0 2 13.5 38.3 46.2 0 control - - 11 53.8 ( 0 ) 0 0.3 1.2 8.9 32.9 56.7 0 oxamniquine 400 15 13 9 33.3 ( 43.7 )
1.7 17 24.3 57
0 0 6 artesunate 600 15 13 12 24.1 ( 59.2 )
6.2 19
12.1
35.6
0 0 27
praziquantel 800 15 13 9 28.9 ( 51.1 )
1.5 13.8 29.6 54.6
0 0 0.4 control - - 11 49.4 ( 16.4 ) 0.9 7.4 18.8 70.2 0.6 0 2.2 oxamniquine 400 23 13 12 28.9 ( 51.1 )
0 0.3 4 27.7
41.8 13
13.3
artesunate 600 23 13 12 25.8 ( 56.3 )
0 0.3 0.3 4.9
32
23.6
38.8
praziquantel 800 23 13 13 40.5 ( 31.6 )
0 0.6 1.4 10.5 61.2 25.8
0.4 control - - 12 59.1 ( 0 ) 0 0.1 1.3 10.4 42 45.1 1a : statistically signicant difference in relation to control ( p 0.05 ) ; b : statistically signicant difference of artesunate in relation to praziquantel and oxamniquine ( p 0.05 ) ; c : statistically signicant difference of artesunate in relation to praziquantel ( p 0.05 ) ; ni : schistosomules with damaged intestines that did not allow their identification .
a : statistically signicant difference in relation to control ( p 0.05 ) ; b : statistically signicant difference of artesunate in relation to praziquantel and oxamniquine ( p 0.05 ) ; c : statistically signicant difference of artesunate in relation to praziquantel ( p 0.05 ) ; ni : schistosomules with damaged intestines that did not allow their identification .
table iiadult worm burden recovered from mice infected with 200 schistosoma mansoni cercariae treated with single dose by oral route as monotherapy and submitted to euthanasia ( treated and control groups ) 42 days after treatment
animals
( n ) worms
n ( % reduction ) treatment schedule ( mg / kg ) treated after infection
( days ) treated examined mean of worm
( % reduction ) males females immature worms oxamniquine 200 15 13 12 33.7 ( 46.8 )
194 ( 49.7 )
191 ( 53.8 )
19 ( 4.7 ) artesunate 300 15 13 13 22.5 ( 61.4 )
129 ( 66.5 )
134 ( 66.5 )
45 ( 15.4 )
praziquantel 400 15 13 12 41.2 ( 34.9 )
244 ( 36.8 )
223 ( 37.2 ) 39 ( 7.7 ) control - - 13 58.4 ( 0 ) 386 ( 0 ) 355 ( 0 ) 18 ( 0 ) oxamniquine 200 23 12 12 52.4 ( 25.7 ) 228 ( 39.6 )
273 ( 39.3 )
128 ( 20.3 )
artesunate 300 23 12 11 43.7 ( 43.2 )
200 ( 47.5 )
248 ( 44.9 )
33 ( 6.9 ) praziquantel 400 23 12 12 52.4 ( 25.7 ) 277 ( 27.3 ) 282 ( 37.8 )
70 ( 11.1 ) control - - 12 70.6 ( 0 ) 381 ( 0 ) 450 ( 0 ) 18 ( 0 ) oxamniquine 400 15 15 15 40.8 ( 55.1 )
233 ( 65.8 )
270 ( 60.4 )
104 ( 16.8 ) artesunate 600 15 13 15 35.1 ( 61.4 )
241 ( 63.6 )
261 ( 61.7 )
24 ( 4.6 ) praziquantel 800 15 15 15 53.8 ( 40.9 )
339 ( 48.8 )
362 ( 46.9 )
52 ( 6.9 ) control - - 14 97.5 ( 0 ) 662 ( 0 ) 682 ( 0 ) 21 ( 0 ) oxamniquine 400 23 14 13 20.9 ( 75 )
64 ( 88.9 )
113 ( 77.3 )
95 ( 34.9 )
artesunate 600 23 14 14 327 ( 57.9 )
141 ( 76.6 )
132 ( 73.4 )
185 ( 40.4 )
praziquantel 800 23 14 12 56.8 ( 37.4 )
329 ( 42.9 )
314 ( 36.8 ) 38 ( 5.6 ) control - - 13 83.8 ( 0 ) 577 ( 0 ) 497 ( 0 ) 15 ( 0)a : statistically signicant difference in relation to control ( p 0.05 ) .
a : statistically signicant difference in relation to control ( p 0.05 ) .
table iiidistribution of young worms recovered from mice infected with 200 schistosoma mansoni cercariae treated with single dose by oral route as monotherapy and combination of drugs and submitted to euthanasia ( treated and control groups ) five days after treatment animals
( n ) distribution of schistosomules per evolutive stage
( % ) treatment schedule
( mg / kg ) treated after
infection
( days ) treated examined mean of worm
( % reduction ) 1 2 3 4 5 6 ni praziquantel 400 14 11 10 29.3 ( 32.6 ) 0.3 5 24 68 0.3 0 1.6 praziquantel 800 14 11 11 23.5 ( 46 )
0.4 4.7 31 54.3
6.6 0 3.1 artesunate 300 14 11 10 17.9 ( 58.9 )
1.2 8.7 16.9
53.5
0.6 0 19.2
artesunate 600 14 11 9 7.7 ( 82.3 )
1.4 20.3
7.2
34.8
1.4 0 34.8
praziquantel 400 + artesunate 300 14 12 12 9.8 ( 77.5 )
2.5 16.9 29.7
42.4
0 0 8.5
praziquantel 800 + artesunate 600 14 12 11 9.1(79.1 )
1 5.9 18.8 55.4
1 0 17.8
control - - 12 43.5 ( 0 ) 0.6 3.8 18.6 73.9 2.3 0 0.8 praziquantel 400 21 11 10 57.6 ( 5.6 ) 0 1.7 3.8 34.9 44.4 13.7
1.4 praziquantel 800 21 11 11 36.0 ( 41 )
0 0.3 9.6 34.1 45.4 9.6
0.8 artesunate 300 21 11 11 26.9 ( 55.9 )
0 0.3 1.4 10.1 29.4 14.5
44.3
artesunate 600 21 12 12 20.6 ( 66.2 )
0 0.8 0 15.4 35.2 4.9
43.7
praziquantel 400 + artesunate 300 21 12 11 29.3 ( 52 )
0 0.9 3.4 27 27.6 4.7
36.6
praziquantel 800 + artesunate 600 21 12 11 19.2 ( 68.5 )
0 0.5 4.3 19.9 38.9 8.1
28.4
control - - 11 61 ( 0 ) 0 0.3 3.3 21.6 37.9 35.2 1.8a : statistically signicant difference in relation to control ( p 0.05 ) ; ni : schistosomules with damaged intestines that did not allow their identification .
a : statistically signicant difference in relation to control ( p 0.05 ) ; ni : schistosomules with damaged intestines that did not allow their identification .
table ivresults obtained using mice experimentally infected with 50 schistosoma mansoni cercariae treated by oral route single dose as monotherapy 14 or 21 days after infection and sacrificed 100 days after infection
animals
( n ) distribution of worms
( % ) treatment schedule
( mg / kg ) treated after
infection
( days ) treated examined mean of worm
( % reduction ) mesentery liver dead worms
in the liver
( % ) oogram
changes
( % ) oxamniquine 200 14 15 11 7.1 ( 65 )
86.2 13.8 0 45.5
artesunate 300 14 15 9 7.0 ( 65.3 )
94.9 5.1 0 11.1 praziquantel 400 14 15 13 12.6 ( 37.6 ) 97.6 2.4 0 0 oxamniquine 200 21 15 11 7.4 ( 63.6 )
93.6 6.4 0 27.3 artesunate 300 21 15 13 5.2 ( 74.3 )
95.6 4.4 0 16.4 praziquantel 400 21 15 7 9.3 ( 54 )
82.4 17.6 0 28.6 control - - 13 20.2 ( 0 ) 88.5 11.5 0 0 oxamniquine 400 14 15 11 5.2 ( 67.9 )
76.2 23.8 9.5 63.6
artesunate 600 14 15 13 4.5 ( 72.2 )
81 19 0 15.4 praziquantel 800 14 15 8 9.5 ( 41.4 ) 76.9 23.1 0 0 oxamniquine 400 21 15 12 6.8 ( 58 )
85.2 14.8 0 58.6
artesunate 600 21 15 11 5.7 ( 64.8 )
87.3 12.7 0 27.3 praziquantel 800 21 15 7 7.9 ( 51.2 )
83.6 16.4 0 14.3 control - - 15 16.2 ( 0 ) 86.1 13.9 0 0a : statistically significant difference in relation to untreated control ( p 0.05 ) .
a : statistically significant difference in relation to untreated control ( p 0.05 ) . except for praziquantel , administered at the dose of 400 mg / kg , 15 or 23 days post - infection ,
it was observed a significant decrease in the mean number of worms recovered by perfusion in all the other therapeutic schedules used .
oxamniquine reduced from 70.2 - 57% the young worms at fourth evolutive stage , when treatment was administered 15 days after infection and it was observed a statistically significant increase in the percentage of worms ( 4th evolutive stage ) when the drug was used 23 days after infection ; the drug also reduced 70% of the worms at the sixth evolutive stage and increased from 1% ( control group ) to 13.3% ( oxamniquine 400 mg / kg ) the percentage of unidentified worms due to intestinal damages ( ni ) , when treatment was administered 23 days post - infection .
treatment with artesunate was responsible for a significant decrease in the percentage of young worms at third stage ( 300 mg / kg , treatment on 15 days after infection ) , as well as an increase in the percentage of worms at second stage ; there was also a decrease about 30% and 50% in the percentage of worms at third and fourth stages , respectively ( dose of 600 mg / kg , treatment 15 days after infection ) and diminished by almost half the percentage of worms at fourth , fifth and sixth evolutive stages ( dose of 600 mg / kg , treatment 23 days after infection ) .
the percentage of immature worms , which could not be assigned to any of the six stages and were considered as ni , was at most 4% in untreated mice .
on the other hand , a significant increase in the percentage of ni could be observed , varying from 16.9% ( animals treated 15 days post - infection with 300 mg / kg artesunate ) to 38.8% , when artesunate ( 600 mg / kg ) was administered 23 days after infection . in relation to the other two drugs ,
only oxamniquine ( 400 mg / kg , treatment 23 days after infection ) showed a significant increase in the percentage of ni ( 13% , p < 0.05 ) ( table i ) .
in all the schedules using different doses of oxamniquine , artesunate and praziquantel , 15 or 23 days post - infection , activity evaluation performed 42 days after infection showed a significant reduction in the mean of recovered worms , varying from 25.7% ( when 200 mg / kg oxamniquine or 400 mg / kg praziquantel were used ) to 75% when treatment with 400 mg / kg oxaminiquine was administered 23 days after infection .
the animals treated with 200 mg / kg or 400 mg / kg oxamniquine , or with 300 mg / kg or 600 mg / kg artesunate , 15 or 23 days after infection , showed a significant statistical reduction in the number of collected male and female worms .
treatment with praziquantel resulted in significant reduction only in the number of male worms , about 40% in reduction when doses of 400 mg / kg or 800 mg / kg were administered 23 or 15 days post - infection , respectively .
the percentage of immature worms collected reached a maximum of 2.4% in untreated mice of the control group .
treatment with 300 mg / kg artesunate , 15 days after infection or 600 mg / kg 23 days after infection , significantly increased the percentage of immature worms ( 15.4% and 40.4% , respectively ) .
treatment with 200 mg / kg or 400 mg / kg oxamniquine , 23 days post - infection , significantly increased the percentage of recovered immature worms ( 20.3% and 34.9% , respectively ) . when treatment with 400 mg / kg oxamniquine was administered 15 days after infection
, there was a significant statistical increase of 16.8% in the percentage of immature worms ( table ii ) .
in the experiments using praziquantel and artesunate in monotherapy or in association , it was observed a significant reduction in the mean number of worms collected by perfusion , except for the groups treated with 400 mg / kg praziquantel , 14 or 21 days after infection . when treatments performed in monotherapy were compared with those ones using drugs in association , the results related to decrease in the average of worms were similar .
praziquantel used in monotherapy significantly reduced the percentage of fourth stage worms ( 400 mg / kg and 800 mg / kg administered 21 days after infection ) ; artesunate in monotherapy was more effective reducing the number of worms ( 3rd and 4th stages ) , when used at the doses of 300 mg / kg or 600 mg / kg , 21 days after infection .
it was observed a significant increase in the number of young worms , which were not identified due to intestinal damages in animals treated with artesunate in monotherapy or with other drug in association , but not in treatment schedules with only praziquantel ( table iii ) .
mice treated with oxamniquine ( 200 mg / kg or 400 mg / kg ) , artesunate ( 300 mg / kg or 600 mg / kg ) or praziquantel ( 400 mg / kg or 800 mg / kg ) , 14 or 21 days post - infection , and evaluated 100 days after infection , presented a significant reduction in the number of worms ( 37 - 74% ) in relation to the control group .
no significant difference in reduction of the average of worms between the treated groups at different schedules could be observed .
worm distribution in mesentery and liver was similar to the control group and no dead worms were detected in the liver .
nevertheless , the oogram was altered in all the groups , except in those treated with praziquantel on days 14 post - infection ( table iv ) .
it is important to emphasise that even performing perfusion 100 days after infection , a part of the recovered worms in treated groups ( 400 mg / kg oxamniquine and 600 mg / kg artesunate ) remained small and with fragile aspect .
most of the females were with a clear - looking intestine , seeming to be female immature worms . in the group treated with artesunate ( 600 mg / kg , 21 days post - infection ) 16 out of 34 ( 47.1% )
females presented immature characteristics , whereas 14 out of 36 ( 38.9% ) females seemed to be immature in the group treated 14 days after infection . in the group treated with oxamniquine ( 400 mg / kg , 21 days post - infection ) 22 out of 49 ( 44.9% )
females showed an immature aspect , while eight out of 28 ( 28.6% ) females showed an immature aspect in the group treated 14 days after infection .
the asynchronous development of s. mansoni at the pre - patent phase was clearly observed in this study and the distribution of the immature worms recovered in the untreated control groups was similar to that reported by barbosa et al .
these results here presented show that the drug interferes in the worm development , slowing or blocking the development of parasites , since significant percentages of worms with an immature aspect were detected up to 100 days after infection .
this original finding has important implications in the fields of pathology , diagnosis and epidemiology of schistosomiasis .
oogram alteration was observed in worms of the group treated with oxamniquine ( 200 mg / kg or 400 mg / kg ) , 14 or 21 days after infection , and submitted to euthanasia 42 days post - infection , indicating that treatment interfered with sexual maturation of the worms , since immature females were recovered . in the animals treated with 300 mg / kg or 600 mg / kg artesunate , 14 or 21 days post - infection , a small percentage of oogram changes
( 1999 ) , treatment with artesunate , at the postural phase , is capable of interrupting egg - laying only temporarily .
praziquantel and derivatives of artesunate shown to be effective in different stages of worm development , being suggested that these drugs would be more efficacious when administered in association than in monotherapy ( inyang - etoh et al .
promising results were obtained with praziquantel / artesunate in association , when administered in s. mansoni and schistosoma japonicum infected mice , presenting immature and mature worms , simultaneously ( utzinger et al .
( 2000 ) in infected patients , in an endemic area for s. mansoni . in the present study
, the results obtained with combination of 400 mg / kg praziquantel + 300 mg / kg artesunate , or 800 mg / kg praziquantel + 600 mg / kg artesunate , administered 14 or 21 days post - infection , did not show therapeutic advantages , since the profile presented by drug associations was similar to that observed when artesunate was administered alone .
perhaps , a better result can be obtained if the association is used in mixed infections , with adult and immature worms ( utzinger et al . 2001 ) .
the experimental chemotherapy at the pre - postural phase of s. mansoni is a field of great importance for development of antischistosomal drugs , due to its potential to eliminate the parasitism before lying of eggs , which cause the major injuries responsible for the disease - the granulomatous inflammatory reactions ( enk et al .
thus , experimental chemotherapy is of the utmost importance and deserves a greater number of studies in this direction .
worms treated at the early phase of infection ( unfertile worms ) , 100 days post - chemotherapy , could maintain an immunological response , as well as the presence of circulating antigens in blood , even in absence of eggs in the faeces .
these findings represent a major cause of confusion regarding the interpretation of schistosomiasis mansoni diagnosis : the absence of eggs in the faeces , but maintenance of specific immune response , the presence of circulating antigens and genetic material of s. mansoni worms ( detected by polymerase chain reaction techniques ) .
the results obtained allow us to conclude that the schistogram method used in this study proved to be a useful tool for experimental evaluation of the activity of antischistosomal drugs , at the early stages of infection , besides being a good model to investigate which of the evolutive stages are more sensitive to antischistosomal drugs . | mice infected with schistosoma mansoni were treated with oxamniquine , praziquantel , artesunate at the pre - patent phase , aiming at observing schistogram alterations .
half of the animals were perfused five days post - treatment for counting and classification of immature worms , based on pre - established morphological criteria ( schistogram ) ; the remaining animals were evaluated 42 or 100 days after infection and perfusion of the portal - system was performed for collection and counting of adult worms and oogram .
it was observed that oxamniquine and artesunate treatment administered at the pre - postural phase causes significant reduction in the number of immature and adult worms .
however , there was little reduction with praziquantel when used at the dose of 400 mg / kg for treatments administered 14 , 15 , 21 or 23 days post - infection .
artesunate was responsible for significant alterations in development of young worms , as well as for a higher number of worms presenting intestinal damages .
immature adult worms were detected in mice treated with artesunate or oxamniquine at the pre - patent phase of infection and recovered by perfusion 100 days after infection .
schistogram proved to be a very useful tool for experimental evaluation of the activity of antischistosomal drugs and a good model to identify the most sensitive stages to drugs . |
Photo: Xinhua News Agency/Getty Images
In a move so brilliant, so masterful, and so perfect I can only hope it is real, a woman in China reportedly convinced her 20 different boyfriends (!) to buy her 20 new iPhone 7s (!!), which she then resold for money she used to purchase a house (!!!).
According to a report from the BBC, a person called Proud Qiaoba (not their real name) first wrote up the story on Chinese blogging platform Tian Ya Yi Du, about their friend, Xiaoli (also not her real name). According to the post, Xiaoli sold the new iPhones for about 120,000 Chinese yuan (approximately $18,000) to a tech resale company called Hui Shou Bao. From there, she used the money to pay for the deposit on a new house.
While the whole thing sounds fairly suspect and a bit like the blog post version of the Thinking-Face Emoji, the BBC did confirm with Hui Shou Bao that the company recently purchased 20 iPhone 7s from a woman earlier in October. Which means there is hope for this scam yet. Now if you’ll excuse me, I’m off to steal 20 of your men and make them buy me iPhones.
Update 11/1/16: A new report from BuzzFeed News has officially killed my hopes that this scam could be real. According to BuzzFeed, the blog in which the story was published is a known hot spot for gossip. The blogger who wrote the story appeared to have only joined to platform days before writing the cell-phone-scam post, which is, obviously, suspect. On top of that, the tech resale company, Hui Shou Bao, recently posted a job opening seeking someone competent in “methods of media manipulation.” It’s likely, BuzzFeed notes, this whole thing was just a scheme cooked up by Hui Shou Bao for attention. A scammer can dream, though. ||||| Image copyright iStock
Buying a house is generally seen as one of most costly purchases one can make. It's especially true in China, where house prices continue to rise.
Given what a the challenge it can be to get on the property ladder in the country, it's probably no surprise that Chinese social media was buzzing with one particular property story last week.
It started when a blog was published on the popular blogging platform the Tian Ya Yi Du forum, by a person writing under the pseudonym 'Proud Qiaoba'.
Proud Qiaoba penned a tale that, if we hadn't been able to verify it ourselves, would seem like the plot of a pretty average airport romance novel.
The lead character in Proud Qiaoba's account is a colleague, whom Chinese media have dubbed 'Xiaoli' (not her real name).
Xiaoli, a woman from the city of Shenzhen in southern China, asked each of her 20 current boyfriends to buy her a newly launched iPhone 7. She then sold all of the phones to a mobile phone recycling site called Hui Shou Bao for 120,000 Chinese yuan (about £14,500), and used the money to put down a deposit on a house in the countryside.
Proud Qiaoba wrote in the blog post that when Xiaoli showed her new house to their group of friends, they were all very surprised when she revealed how she had managed to obtain the money for the deposit.
"Everyone in the office is talking about this now," wrote Proud Qiaoba, "Who knows what her boyfriends think now this news has become public."
Proud Qiaoba added that Xiaoli "is not from a wealthy family. Her mum is a housewife and her dad is a migrant worker, and she is the oldest daughter. Her parents are getting old and she might be under a lot pressure hoping to buy them a house... But it's still unbelievable that she could use this method!"
Many people on China's microblogging site Sina Weibo have been expressing their surprise at Xiaoli's enterprise and quick work in convincing her 20 lovers to each buy her the latest in Apple's mobile coterie - particularly since the iPhone 7 was only recently launched, on 16 September of this year,
A hashtag which translates as '20 mobiles for a house' quickly began to circulate on Weibo, and became the country's top trend. It has now been used in excess of 13 million times.
Many social media users, like 'small sand is growing', have expressed admiration for Xiaoli.
"I can't even find one boyfriend. She can actually find 20 boyfriends at the same time and even get them to buy her an iPhone 7. Just want to ask her to teach me such skills."
Another, 'TST' praised her enterprising nature, saying that she has "a bright future."
But others haven't been so complimentary.
'Little Bee' wrote that Xiaoli was "the most shameless person".
Others were suspicious and wondered if the whole story was an elaborate product placement for Hui Shou Bao, the mobile phone recycling business.
BBC Trending approached Hui Shou Bao and a company spokesperson confirmed that they had indeed purchased 20 iPhones from a female client at the beginning of October and paid 6,000 Chinese yuan (about £725) for each one.
We put in a request to interview Xiaoli through the company. They responded to our email saying that they had asked their client if she would like to speak to us, but she had declined.
"Her day-to-day life has been affected (from the local media attention) and she doesn't want the media to continue covering this story," they said, "so she has turned down your interview request."
Blog by Ruhua Xianyu
Next Story: Saudi nepotism rumours, the Australian media and a confusing crying man
Image copyright Laura DiMichele-Ross
Find out what's buzzing in the social media world today. READ MORE
You can follow BBC Trending on Twitter @BBCtrending, and find us on Facebook. All our stories are at bbc.com/trending. | – One woman's personal journey to homeownership in China—which involved 20 iPhone 7s, 20 boyfriends, and some masterful manipulation—has gone viral, with New York Magazine calling it "a move so brilliant ... I can only hope it is real." It doesn't look like it is, but the story of why it may not be is as interesting as the tale itself. The story broke on popular blogging platform Tian Ya Yi Du, where a person writing under the name "Proud Qiaoba" said that another woman with the pseudonym Xiaoli was able to convince her 20 current boyfriends to buy her the just-out iPhone 7. As the story goes, she immediately turned around and sold them to Hui Shou Bao, a mobile phone recycling site, for roughly $18,000. And, ta da, a down payment. The story got wide pickup following a report by the BBC, which did try to verify the story: Hui Shou Bao told the BBC it did in fact buy 20 iPhones from a female client in early October, paying close to $900 for each. The BBC's attempt to secure an interview with Xiaoli via the company failed. BuzzFeed unpacks the reasons why the story smells bad: For starters, Tian Ya Yi Du isn't a journalistic paragon but a "gossipy" forum known for giving birth to rumors. "Proud Qiaoba" (BuzzFeed has it as "Proud Chopper") opened an account just four days before he posted the story (twice, once as "Shocking!!" and once as "Breaking News!!"). Potentially most damning of all: A job ad posted by Hui Shou Bao seeking someone "passionate about producing internet events" and skilled in "methods of media manipulation." (This type of fake news is very profitable.) |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Early Childhood Nutrition
Improvement Act''.
SEC. 2. ELIGIBILITY CERTIFICATION CRITERIA FOR PROPRIETARY CHILD CARE
CENTERS.
Section 17(a)(6) of the Richard B. Russell National School Lunch
Act (42 U.S.C. 1766(a)(6)) is amended--
(1) in subparagraph (E), by striking ``and'' at the end;
(2) in subparagraph (F), by striking the period at the end
and inserting ``; and''; and
(3) by adding at the end the following:
``(G) in the case of an institution described in
paragraph (2)(B), the eligibility determination shall
be in effect for 6 months after the date such
institution is approved by the State under section
17(d).''.
SEC. 3. REVIEW OF SERIOUS DEFICIENCY PROCESS.
Section 17(d)(5) of the Richard B. Russell National School Lunch
Act (42 U.S.C. 1766(d)(5)) is amended by adding at the end the
following:
``(F) Serious deficiency process.--
``(i) In general.--Not later than 1 year
after the date of enactment of this
subparagraph, the Secretary shall review and
issue guidance and, as appropriate, regulations
regarding the serious deficiency process for
the program under this section.
``(ii) Review.--In carrying out clause (i),
the Secretary shall review, at a minimum, the
processes for, and those involved in--
``(I) determining when there is a
serious deficiency, including--
``(aa) what measures
automatically result in a
finding of serious deficiency;
and
``(bb) how differentiation
is being made between--
``(AA) a reasonable
margin of human error
and systematic or
intentional
noncompliance; and
``(BB) State-
specific requirements
and Federal
regulations;
``(II) appealing and mediating a
finding of serious deficiency,
including--
``(aa) findings related to
State-specific requirements;
and
``(bb) processes for
ensuring officials involved in
appeals and mediation are fair
and impartial;
``(III) determining the
circumstances under which a corrective
action plan is acceptable; and
``(IV) termination and
disqualification, including maintenance
of the list under subparagraph (E).
``(iii) Guidance and regulations.--
``(I) In general.--After conducting
the review under clause (ii), the
Secretary shall make findings from the
information collected and issue
guidance and, as appropriate,
regulations from such findings that
will assist sponsoring organizations,
State agencies, and the Food and
Nutrition Service in ensuring a fair,
uniform, and effective administration
of the serious deficiency process,
while retaining program integrity.
``(II) Scope.--Such guidance or, as
appropriate, regulations shall
include--
``(aa) clarity on the
different measures for
noncompliance;
``(bb) appeals process for
a finding of serious deficiency
or a determination that a
corrective action plan is
inadequate; and
``(cc) adequate timeframes
under a corrective action plan
for compliance that are
consistent for all types of
institutions, including family
or group day care homes.''.
SEC. 4. AUTHORIZATION OF REIMBURSEMENTS FOR ADDITIONAL MEAL OR SNACK.
Section 17(f)(2) of the Richard B. Russell National School Lunch
Act (42 U.S.C. 1766(f)(2)) is amended--
(1) by striking ``(2)(A) Subject to subparagraph (B) of
this paragraph'' and inserting the following:
``(2) Disbursements.--
``(A) In general.--Subject to subparagraph (B)'';
and
(2) by amending subparagraph (B) to read as follows:
``(B) Limitation.--No reimbursement may be made to
any institution under this paragraph, or to family or
group day care home sponsoring organizations under
paragraph (3), for more than--
``(i) 2 meals and 1 supplement or 1 meal
and 2 supplements per day per child; or
``(ii) 3 meals and 1 supplement or 2 meals
and 2 supplements per day per child, for each
child that is maintained in a child care
setting for more than 8 hours per day.''.
SEC. 5. ADJUSTMENTS.
Section 17(f)(3)(A) of the Richard B. Russell National School Lunch
Act (42 U.S.C. 1766(f)(3)(A)) is amended by striking ``Consumer Price
Index for food at home'' each place it appears and inserting ``Consumer
Price Index for food away from home''.
SEC. 6. ADVISORY COMMITTEE ON PAPERWORK REDUCTION.
Section 17 of the Richard B. Russell National School Lunch Act (42
U.S.C. 1766) is amended by adding at the end the following:
``(v) Advisory Committee on Paperwork Reduction.--
``(1) Establishment.--Not later than 180 days after the
date of the enactment of this subsection, the Secretary shall
establish an advisory committee (hereafter in this subsection
referred to as the `Advisory Committee') to carry out the
duties described in paragraph (2).
``(2) Duties.--The duties of the Advisory Committee shall
be to--
``(A) examine the feasibility of reducing
unnecessary or duplicative paperwork resulting from
regulations and recordkeeping requirements, including
paperwork resulting from additional State requirements,
for those participating or seeking to participate in
the program under this section including State
agencies, family child care homes, child care centers,
and sponsoring organizations; and
``(B) provide recommendations to reduce such
paperwork for participants in the program under this
section while ensuring that proper accountability and
program integrity are maintained.
``(3) Membership.--The Advisory Committee shall be composed
of 1 member representing each of the following entities and
such other members as the Secretary determines to be
appropriate:
``(A) A public nonprofit center.
``(B) A private nonprofit center.
``(C) A family or group day care home.
``(D) A Head Start center.
``(E) A for-profit center.
``(F) An emergency shelter.
``(G) An adult day care center.
``(H) A State agency.
``(I) Sponsoring organizations for centers and
family or group day care homes.
``(J) An anti-hunger advocacy organization.
``(K) An at-risk, after school program.
``(L) A child care advocacy organization.
``(4) Considerations.--In developing the recommendations
described in paragraph (2), the Advisory Committee shall
consider--
``(A) information, recommendations, and reports
from the Paperwork Reduction Work Group established by
the Food and Nutrition Service pursuant to section
119(i) of the Child Nutrition and WIC Reauthorization
Act of 2004 (Public Law 108-265; 118 Stat. 755); and
``(B) the use of electronic systems and
recordkeeping technologies to reduce paperwork for
program participants.
``(5) Guidance and regulations.--Not later than 2 years
after the date of the enactment of this subsection, the
Secretary shall issue guidance and, as appropriate, regulations
based on the recommendations described in paragraph (2) for
streamlined and consolidated paperwork and recordkeeping
requirements for the program, including recommendations for
reducing paperwork for applications and monitoring and auditing
requirements.
``(6) Report.--
``(A) In general.--Not later than 180 days after
issuing the guidance and regulations described in
paragraph (5), the Secretary shall submit a report to
the Committee on Agriculture, Nutrition, and Forestry
of the Senate and the Committee on Education and the
Workforce of the House of Representatives containing
the information described in subparagraph (B).
``(B) Contents.--The report under subparagraph (A)
shall contain the following:
``(i) In each case in which the Secretary
did not implement a recommendation of the
Advisory Committee, an explanation of why such
recommendation was not implemented.
``(ii) Recommendations for legislative
action that may further strengthen and
streamline the program application and
monitoring process and reduce administrative
burdens on grantees, program participants, and
local, State, and Federal governments.''. | Early Childhood Nutrition Improvement Act This bill amends the Richard B. Russell National School Lunch Act to revise several provisions related to the child and adult care food program. Under current law: (1) an institution that provides child or day care under the program may be reimbursed for up to two meals and one supplement per day per child; and (2) a family or group day care home sponsoring organization may receive the same maximum reimbursement, but only with respect to a child maintained in a child care setting for at least eight hours per day. The bill eliminates this distinction between institutions and sponsoring organizations, and increases maximum reimbursement for both to: (1) two meals and one supplement or one meal and two supplements per day per child; or (2) three meals and one supplement or two meals and two supplements per day per child, for each child maintained in a child care setting for at least eight hours per day. Reimbursements to family or group day care home sponsoring organizations must be adjusted annually to reflect the Consumer Price Index for food away from home, rather than the Consumer Price Index for food at home used under current law. A determination of a for-profit day care center's eligibility to participate in the program shall be in effect for six months. The Department of Agriculture (USDA) must issue guidance and, as appropriate, regulations to assist in ensuring a fair and effective process for the identification, review, and correction of serious program deficiencies. USDA shall establish an advisory committee to examine the feasibility of reducing unnecessary or duplicative paperwork for those participating or seeking to participate in the program. |
parasites are common in the animal kingdom , and they play significant roles in marine aquaculture . lernanthropus de blainnville , 1822 , is the most widespread genus of the family lernanthropidae which is considered to be a common genus of parasitic copepods on fishes .
they attach to the gill filaments of its host by means of the piercing action of the antennae , assisted by maxillipeds and third legs .
most members are also characterized by the presence of plate - like structures and outgrowths of the fourth leg - bearing segment , often completely covering the posterior half of the body .
occasionally , the parasitic copepods may injure their host by feeding on mucus and skin and sucking the host 's blood especially those which attach to the gills .
such feeding activity can cause mechanical damage to the skin , fin erosion , and osmotic stress and may result in death in extreme cases .
the combination actions of the antennae , maxilla , and maxilliped together with mandible of lernanthropus latis which caused the damage were detected under light and scanning electron microscopies ( sem ) .
the pathological effect such as erosion , haemorrhages , hyperplasia , and necrosis along the secondary lamellae of gill filaments of l. latis was observed with a great severity at the site of attachment .
it is important to study the biology and life cycle due to the attachment location on the gill filaments and their blood - feeding habit which generates a threat to their host when outbreaks occur .
thus , some prophylactic measures to prevent their proliferation can be determined while factors working on the strategy of the infestation also can be clarified .
parasitic lernanthropus species have a complex life cycle with a number of different larval stages . between each
pioneer descriptions of life cycle of family lernanthropidae have been done . in the investigation on l. kroyeri , nine larval stages were observed .
the stages were named nauplii i , nauplii ii , infective copepodid , fixed copepodid i , ii , iii , and iv , preadult , and adult . as the species of lernanthropus from cage culture in setiu wetland , terengganu , have been identified as lernanthropus latis , obtaining
the life cycle details was the main purpose in this research . within laboratory condition , the salinity and temperature used
were maintained the same as at the cage site , where the seabass was taken .
lates calcarifer ( seabass ) , in size ranging from 400 to 600 g , was collected from sea cage culture in setiu wetland , terengganu , malaysia .
the fish were brought back alive to the laboratory of universiti malaysia terengganu for dissection .
adult female lernanthropus latis with eggs were isolated from the seabass gills and placed in a vial containing 20 ml of filtered seawater .
observation was done every hour for detection of nauplii i , nauplii ii , and infective copepodid stage .
the copepodids in the 20 ml filtered seawater were gently poured into a polytank containing 150 fingerling ( 2 - 3 inches in size ) in 60 litres of seawater .
drawing was done as soon as the new stage was discovered using camera lucida which was connected to compound microscope .
the adult female clasped their second antennae assisted by third legs to the lamellae - bearing sides of the primary lamellae ( gill filaments ) .
the body was positioned between the hemibranchs , with their axis parallel to the lamellae axis .
the egg string is long and uniseriate ; some were coiled with numerous eggs inside the string .
the numerous eggs were arranged lengthwise down , where each egg was in its own chamber inside the sac . when the egg is about to hatch , it expands and pushes itself out of the sac membrane ( figure 2 ) .
after 15 minutes of observation , the eggs hatch and release nauplii i ( figure 3(a ) ) .
the hatching of eggs occured in random and some of them did not hatch at all .
the range of body length and width of nauplii i is 1.43 to 1.84 mm and 0.84 to 0.90 mm , respectively , bearing three pairs of anterolateral appendages ( figure 3(a ) i ) and two modified caudal setae ( figure 3(a ) ii ) at the posterior of the body .
nauplii ii ( figure 3(b ) ) moulted 15 hours after hatching , also bearing three pairs of anterolateral appendages and two modified caudal setae at the posterior of the body . at this stage ,
setae of modified legs protrudes out of the body membrane posteriorly ( figure 3(b ) i ) .
the range of body length and width is 1.78 to 2.07 mm and 0.80 to 1.00 mm , respectively .
infective copepodid ( figure 3(c ) ) transformed at 26 to 37 hours after hatching .
the body length and width are 2.18 to 2.65 mm and 0.63 to 0.95 mm , respectively .
first leg , second leg , and uropod with setae elongated downwards are observable compared to nauplii ii stage ( figure 3(c ) ii , iii , and iv ) .
all three stages were known as free - swimming stages as they swim randomly without needing a host .
the last stage of free swimming , known as infective copepodid , was the stage at the outset of host searching and attachment .
the body length and width are 2.72 to 2.97 mm and 1.06 to 1.07 mm , respectively , cephalothorax being the largest portion of body ( figure 4(a ) i ) .
the antennule , antenna , maxillule , mandible , maxilla , maxilliped , and first leg were at the cephalothorax .
fixed copepodid ii ( figure 4(b ) ) moults 84 hours after hatching . the body length and width
fixed copepodid iii ( figures 5(a ) and 5(b ) ) moults 95 hours after hatching .
the body length and width are 2.97 to 3.74 mm and 1.07 to 1.52 mm , respectively .
third leg bifurcate for male ( figure 5(a ) i ) and extend for female ( figure 5(b ) i ) .
bifurcated fourth leg elongated for male and female ( figures 5(a ) ii and 5(b ) ii ) . fixed copepodid iv ( figures 5(c ) and 5(d ) ) moults 109 hours after hatching . the body length and width are 3.9 to 7.44 mm and 1.48 to 3.02 mm , respectively .
third and fourth legs remain in the same shape but are continuously growing for both male and female .
preadult moult ( figures 5(e ) and 5(f ) ) 207 to 483 hours after hatching .
the body length and width are 8.30 to 8.78 mm and 3.12 to 3.36 mm , respectively .
spines present at the tip of third and fourth leg for both male and female .
the appendages such as antennae , antennule , maxilla , maxillule , maxilliped , first leg , second leg , fourth leg , and genital organ all remain in the same shape but increase in size until reaching adult . as for the third leg , the bifurcation process for male and curve edging for female apparently increase till adult .
lernanthropus latis took 482 hours ( 20 days ) to complete the life cycle under laboratory conditions .
two - to - four fingerlings were dissected every five hours resulting in the finding of the nine developmental stages as mentioned above .
the third leg and dorsal shield are the main parts to differentiate the gender between male and female copepodid .
the gender was able to be differentiated from the first copepodid ( copepodid i ) although the larvae were very similar morphologically for both male and female .
however , the period of time of larvae moulting from stage to stage and completion the whole life cycle was not stated in the research . in this study , the gender
the families of caligidae and lernanthropidae share the same order , siphonostomatoida [ 3 , 4 ] . in the life cycle aspect ,
both families obtain a similarity in which the first three stages : nauplii i , nauplii ii , and copepodid or fixed copepodid ( for family lernanthropidae ) are in the phase of free swimming ( planktonic ) . in order to enter the parasitic phase , an infection onto host
, the stage of copepodid is the main part in which it will start to settle on the host and moult into different stages .
the caligus is mostly attached on the skin by use of the frontal filament but the lernanthropus uses the antenna to grip to gill filament and remains at the same location until adult .
another research on lernanthropus latis life cycle revealed that the time taken by nauplius stage to moult is six to 12 hours , copepodid i is 24 to 36 hours , and the remaining copepodid ii , iii , iv , v and immature stage was 54 hours , 78 hours , 126 hours , 174 hours , and 222 hours respectively .
the nine stages found were similar to the previous study . in the meantime , a significant interaction between water temperature and salinity was detected in determining the success of egg hatching .
the best rate of egg hatching was documented within 35 salinity and 30c of temperature .
a research on life cycle of caligus rogercresseyi in rainbow trout was made under natural condition of light and temperature .
five different temperatures were set up at 10.3c , 12.4c , 12.8c , 15.2c , and 16.7c .
those temperatures resulted in 45 , 31 , 32 , 26 , and 18 days , respectively , for c. rogercresseyi to complete a life cycle . from the research , eight developmental stages
the stages were two nauplii , one copepodid , four chalimus , and one adult .
recently , the fish parasites not only play a role in causing fish disease or infecting humans who eat fish but also are used in understanding the fish population . in terms of fish biology ,
the employment of parasites as biological tags is useful in assessing fish stock and migratory pattern . | parasitic crustaceans of lernanthropus latis were isolated from the host , the seabass , lates calcarifer , obtained from a cage culture in setiu wetland , terengganu . the adult females with egg
were kept alive in vials containing 20 ml of filtered seawater and incubated at 30c .
the eggs were monitored every hour and the hatching periods were recorded .
three developmental stages were observed , namely , nauplii i , nauplii ii , and infective copepodid .
the infective copepodids were then transferred into a tank containing 60 litres of seawater with 150 fingerlings for infection purpose .
one fish was sacrificed every 24 hr to inspect the next developmental stage . as a result
, six more stages were obtained within 298 hrs starting from the infection day .
the stages were known as fixed copepodid i , fixed copepodid ii , fixed copepodid iii , fixed copepodid iv , preadult , and adult .
parasitic l. latis takes a 483 hr period to complete a life cycle . |
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Drill Now Act of 2008''.
SEC. 2. DEFINITIONS.
In this Act:
(1) Opened area.--The term ``opened area'' means any area
of the outer Continental shelf that--
(A) before the date of enactment of this Act, was
closed to oil or gas leasing; and
(B) as of the date of enactment of this Act, is
made available for leasing pursuant to section 3(a) and
the amendments made by that section.
(2) Secretary.--The term ``Secretary'' means the Secretary
of the Interior.
SEC. 3. LEASING ON OUTER CONTINENTAL SHELF.
(a) Opening New Offshore Areas to Oil and Gas Development.--
(1) In general.--Sections 104 and 105 of the Department of
the Interior, Environment, and Related Agencies Appropriations
Act, 2008 (Public Law 110-161; 121 Stat. 2118) are repealed.
(2) Eastern gulf of mexico.--Section 104 of the Gulf of
Mexico Energy Security Act of 2006 (43 U.S.C. 1331 note; Public
Law 109-432) is amended to read as follows:
``SEC. 104. DESIGNATION OF NATIONAL DEFENSE AREAS.
``The United States reserves the right to designate by and through
the Secretary of Defense, with the approval of the President, national
defense areas on the outer Continental Shelf pursuant to section 12(d)
of the Outer Continental Shelf Lands Act (43 U.S.C. 1341(d)).''.
(b) Expedited Leasing.--The Secretary may conduct leasing,
preleasing, and related activities for any opened area before June 30,
2012, notwithstanding the omission of the opened area from the Outer
Continental Shelf leasing program developed pursuant to section 18 of
the Outer Continental Shelf Lands Act (43 U.S.C. 1344) for the period
ending June 30, 2012.
(c) No Surface Occupancy.--Any lease issued by the Secretary
pursuant to section 8 of the Outer Continental Shelf Lands Act (43
U.S.C. 1337) for any submerged land of the outer Continental Shelf in
any opened area lying within 25 miles of the coastline of any State
shall include a provision prohibiting permanent surface occupancy under
that lease within that 25-mile area.
(d) Disposition of Revenues From Outer Continental Shelf Areas
Opened Under This Section.--
(1) In general.--Notwithstanding section 9 of the Outer
Continental Shelf Lands Act (43 U.S.C. 1338) and subject to the
other provisions of this section, the Secretary of the Treasury
shall deposit rentals, royalties, bonus bids, and other sums
due and payable from any leased tract within an opened area,
and from all other leased tracts in any other area for which
leases are entered into after the date of enactment of this
Act, as follows:
(A) 50 percent in the general fund of the Treasury.
(B) 50 in a special account in the Treasury, for
allocation by the Secretary among the States in
accordance with paragraph (2).
(2) Allocation.--
(A) In general.--For fiscal year 2009 and each
fiscal year thereafter, the amount made available under
paragraph (1)(B) shall be allocated among States in
amounts (based on a formula established by the
Secretary by regulation) that are inversely
proportional to the respective distances between--
(i) the point on the coastline of each
State that is closest to the geographical
center of the applicable leased tract; and
(ii) the geographical center of the leased
tract.
(B) Prohibition on receipt of amounts.--No State
shall receive any amount under this paragraph from a
leased tract if the geographical center of that leased
tract is more than 200 nautical miles from the
coastline of that State.
(3) Administration.--Amounts made available under paragraph
(1)(B) shall--
(A) be made available, without further
appropriation, in accordance with this section;
(B) remain available until expended; and
(C) be in addition to any amounts appropriated
under--
(i) the Outer Continental Shelf Lands Act
(43 U.S.C. 1331 et seq.);
(ii) the Land and Water Conservation Fund
Act of 1965 (16 U.S.C. 460l-4 et seq.); or
(iii) any other provision of law.
(e) Judicial Review.--
(1) Filing of complaint.--
(A) Deadline.--Subject to subparagraph (B), any
complaint seeking judicial review of any provision of
this section or any action of the Secretary under this
section or relating to areas opened under the
amendments made by subsection (a) shall be filed in any
appropriate United States district court--
(i) except as provided in clause (ii), not
later than the end of the 90-day period
beginning on the date of the action being
challenged; or
(ii) in the case of a complaint based
solely on grounds arising after that period,
not later than 90 days after the date on which
the complainant knew or reasonably should have
known of the grounds for the complaint.
(B) Venue.--Any complaint seeking judicial review
of an action of the Secretary under this section or
relating to areas opened under subsection (a) may be
filed only in the United States Court of Appeals for
the District of Columbia.
(C) Limitation on scope of certain review.--
(i) In general.--Judicial review of a
decision of the Secretary to conduct a lease
sale for areas opened under the amendments made
by subsection (a), including the environmental
analysis relating to such a decision, shall
be--
(I) limited to whether the
Secretary has complied with the terms
of this section and the Outer
Continental Shelf Lands Act (43 U.S.C.
1331 et seq.); and
(II) based upon the administrative
record of that decision.
(ii) Presumption.--In any judicial review
described in clause (i), the identification by
the Secretary of a preferred course of action
to enable leasing to proceed, and the analysis
of the Secretary of any environmental effects
of that course of action, shall be presumed to
be correct unless shown otherwise by clear and
convincing evidence to the contrary.
(2) Limitation on other review.--Actions of the Secretary
with respect to which review could have been obtained under
this section shall not be subject to judicial review in any
civil or criminal proceeding for enforcement.
(f) Repeal of Restriction on Oil Shale Leasing.--Section 433 of the
Department of the Interior, Environment, and Related Agencies
Appropriations Act, 2008 (Public Law 110-161; 121 Stat. 2152) is
repealed. | Drill Now Act of 2008 - Amends the Department of the Interior, Environment, and Related Agencies Appropriations Act, 2008 to repeal its prohibitions against oil and natural gas preleasing and leasing activities in specified offshore areas, including the North Atlantic, the eastern Gulf of Mexico, and the Mid-Atlantic and South Atlantic planning areas.
Declares that the United States reserves the right to designate national defense areas on the outer Continental Shelf (OCS).
Authorizes the Secretary of the Interior (Secretary) to conduct leasing, preleasing, and related activities for any opened area before June 30, 2012.
Requires any lease issued by the Secretary for submerged land of the OCS in any opened area lying within 25 miles of the coastline of any state to include a prohibition against permanent surface occupancy.
Instructs the Secretary of the Treasury to deposit revenues from tracts leased under this Act into: (1) the general fund of the Treasury; and (2) a special account in the Treasury, for allocation among the states in accordance with prescribed guidelines.
Repeals the prohibition against the use of funds to prepare or publish final regulations regarding a commercial leasing program for oil shale resources on public lands or to conduct an oil shale lease sale. |