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according to acog guidelines , a fetus with intrauterine growth restriction ( iugr ) is a fetus with an estimated weight less than the 10th percentile for gestational age . with a prevalence of the 58% in the general population , frequently the etiology of iugr is unknown ; however in several cases it is possible to identify fetal ( infection , malformation , and chromosomal aberration ) , placental ( chorioangioma , infarction , circumvallated placenta , confined placental mosaicism , obliterative vasculopathy of the placental bed , etc . ) , maternal ( chronic hypertension , pregestational diabetes , cardiovascular disease , substance abuse , autoimmune conditions , etc . ) , and external factors that modulate the normal fetal growth , by acting on a genetically predetermined potential growth . iugr represents the second cause of perinatal mortality , after prematurity , and it is related to an increased risk of perinatal complication as hypoxemia , low apgar scores , and cord blood acidemia , with possible negative effects for neonatal outcome [ 8 , 9 ] . liver perfusion is reduced to 30% [ 10 , 11 ] so that the low fetal body weight can be partially caused by impairment of liver protein biosynthesis . this diversion of oxygenated blood to preferential perfusion of vital organs such as the brain , heart , adrenal glands , and spleen [ 1316 ] and reduced flow to less important organs such as muscles , bowel , and kidneys enables the fetus to survive for a considerable period . if the oxygen supply to the myocardium reaches its limit , the myocardium stiffens , and the central venous pressure increases . hemodynamic changes involve maternal uterine , fetal umbilical ( ua ) , and middle cerebral ( mca ) arteries and precordial veins for cardiac effects of placental dysfunction [ 18 , 19 ] . the circulatory adaptation consists in an increased ua and decreased mca blood - flow resistance . mca was found to be a better predictor for fetal outcome in iugr when compared with umbilical artery in terms of sensitivity and predictive value . instead , ductus venosus was considered as the strongest doppler predictor of perinatal mortality in preterm iugr fetuses [ 2527 ] . nevertheless , the use of doppler velocimetry in cases of iugr , although well studied , is still controversial and standardized guidelines are lacking . therefore , doppler ultrasound has to be integrated with several techniques of screening for a complete clinical evaluation of iugr . some authors found out that intrapartum fetal doppler velocimetry , when combined with cardiotocography ( ctg ) , increases the clinicians ' ability to accurately identify fetal hypoxia . in the last years , computerized cardiotocography ( cctg ) has conquered an important role in medical management of pregnancy , especially in high risk patients . cctg monitoring consists in the electric recording of fetal heart rate ( fhr ) and can be considered the most widespread noninvasive method to evaluate fetal well - being during prenatal and intrapartum process . cctg offered a standardized method to evaluate conventional ctg parameters and introduced quantitative measures of linear and nonlinear indices related to fhr generation as a multiparametric analysis of fetal cardiovascular and nervous activity . the presence of significant beat - to - beat variation suggests intact sympathetic / parasympathetic tone and central control indicating normal central nervous system ( cns ) responsiveness and normal local cns metabolic environment reflecting fetal health [ 30 , 31 ] . despite the fact that cctg is widespread , its use is still thwarted because computer programs are considered inevitably based on the current , limited knowledge of fetal heart rate patterns , in relationship to neonatal long - term outcome . for baschat et al . , doppler indices have a more important and statistically significant relationship with perinatal outcome [ 32 , 33 ] . since many authors [ 34 , 35 ] have showed that doppler velocimetry can not be able , alone , to manage iugr fetuses , we performed this retrospective longitudinal study based on a multiparametric analysis . our aim was to evaluate the modifications of velocimetric ( ua , dv , and mca ) and computerized cardiotocographic ( fhr , stv , and apen ) parameters in relationship to days before delivery , in order to find out those associated with earlier fetal compromise in fetal growth restriction . this retrospective longitudinal study was carried out at the public health of federico ii university of naples ( italy ) in a period of five years ( 20082013 ) . the study was conducted on a sample of 375 pregnant women assisted from the 28th week of amenorrhea to delivery . gestational age was accurately established or confirmed from ultrasound measurement of the embryo or fetus in the first trimester . the diagnosis of iugr was based on the evaluation of an abdominal circumference below the 10th percentile . inclusion criteria were caucasian ethnic , singleton pregnancies , absence of preexisting maternal disease , and neonatal weight below the 10th percentile for the gestational age ( weight evaluated according to nomograms by who , november 1 , 2009 ) . antenatal examinations included ultrasound biometry , doppler velocimetry on ua , mca , dv , and antenatal cctg monitoring . newborn baby data ( sex , weight , apgar score , malformation at birth , access to neonatal intensive care , and umbilical artery ph ) were collected . the cardiotocograph is equipped with two transducers : the first one is an ultrasound transducer to detect the fetal heart rate ( fhr ) , posted next to the focus of maximum auscultation of fetal heart ; the second one is a pressure transducer for uterine contractile activity located next to the uterine fundus . the cardiotocograph is connected to a smartphone that , via general packet radio service ( gprs ) , sends traces to the operation center , interfaced to 2ctg2 system ( sea , italy ) for computerized analysis . the following cctg parameters , fetal heart rate ( fhr ) , short term variability ( stv ) , and approximate entropy ( apen ) were examined . we considered a fetal heart rate < 110 or > 160 bpm , a short - term variability < 5th percentile for gestational age , and apen < 5th percentile [ 41 , 42 ] abnormal . doppler evaluation was performed using a toshiba ultrasound nemio xg with a 3.55 mhz curvilinear transducer for transabdominal examination and a 3.753.8 mhz transducer for transvaginal evaluation . ultrasonography was performed in each pregnant woman and the insonation by the pulsed doppler examination was improved with colour doppler images to obtain velocity waveform for ua , mca , and dv . pi of ua was considered abnormal when it was > 97.5th percentile for gestational age , as well as when diastole was absent or reversed . absent / reverse a - wave in dv [ 20 , 34 ] and brain sparing in mca were also detected [ 24 , 44 ] . to discriminate between early and late fetal compromise , the study population was divided into three groups according to the gestational age of delivery ( < 34th ; from 34th to 37th gestational week ; > 37th gestational week at time of delivery ) and data were analyzed as a function of days before delivery . 24 hours was the time interval between doppler alterations ( ductus venous waveform or umbilical artery pi > 95th centile ; absent or reverse a - wave or end - diastolic flow in dv and in ua , resp . , mca pi less than the 5th centile ) and ctg abnormalities ( see criteria acog classification 2009 ) . t - test with the bonferroni adjustment was applied for continuous variables while chi - square test with the bonferroni adjustment was used for categorical variables . t - test investigated the existence of a statistical significant difference between the three groups for cctg ( fhr , stv , and apen ) and doppler velocimetric ( ua , mca , and dv ) parameters . moreover , among patients of each group , each parameter was related to the gestational age using the pearson correlation test . to complete our analysis , patients were also divided according to the physiological or pathological doppler indices and , also in these groups , cctg parameters were analyzed through the t - test also in these groups . statistical significance with bonferroni 's correction was p value < 0.016 . in our study , 98% of women who delivered before the 34th week of gestation had a cesarean section . fetal ph at birth and the apgar score were both in the range of normality ( table 1 ) . groups for maternal age and between each group of study compared to each one of the other two groups for fetal ph ( p < 0.016 ) . chi - square test with bonferroni correction showed a significant difference for the way of delivery , for apgar value at 3 minutes , and for the gender of newborns for each group compared to the other ones . < 34th week and from 34th to 37th week and between from 34th to 37th week and > 37th week groups a difference was found ( p < 0.016 ) . figure 1 shows the percentile of abnormal values for cctg parameters and for doppler indices . chi - square test with bonferroni correction evidenced a statistical significant difference between each group of study compared to each one of the other two ( before the 34th week versus from 34th to 37th week ; before the 34th week versus after the 37th week groups ) for fhr , mca , ua , and dv ( p < 0.016 ) . the only exceptions were found for stv and apen . in particular , stv was found different only between < 34th week and the other two groups , while no difference was found between the two groups of study > 34th week . instead , considering the physiology or pathology of velocimetry , a statistical significant difference for each of cctg indices ( stv p = 0.002 ; apen p = 0.002 ) except for fhr ( p = 0.03 ) was found . figure 2 represents the trend of parameters in the three groups of study during pregnancy until the time of delivery expressed as the probability of finding a pathological value for each gestational age . stv and dv showed the earliest and most important modifications , while ua alterations were more marked only in the in particular , among patients who delivered before the 34th week , pearson correlation reported a decrease of each parameter except for stv and for dv . the correlation was statistically significant for fhr ( r = 0.47 ; p = 0.021 ) , mca ( r = 0.521 ; p = 0.002 ) , dv ( r = 0.721 ; p < 0.002 ) , stv ( r = 0.51 ; p = 0.0001 ) , and apen ( r = 0.41 ; p = 0.035 ) . the only exception was found for ua ( r = 0.073 ; p = 0.84 ) . for patients who delivered from the 34th to the 37th gestational age , the pearson test showed significant correlations for fhr ( r = 0.53 ; p = 0.015 ) , mca ( r = 0.47 ; p = 0.01 ) , dv ( r = 0.49 ; p = 0.002 ) , stv ( r = 0.63 ; p = 0.002 ) , and apen ( r = 0.53 ; p = 0.024 ) . ua is an exception ( r = 0.2 ; p = 0.76 ) . for patients who delivered after the 37th week however , only for fhr ( r = 0.51 ; p = 0.002 ) , mca ( r = 0.436 ; p = 0.01 ) , and dv ( r = 0.52 ; p = 0.002 ) the correlation was statistically significant . for stv ( r = 0.073 ; p = 0.67 ) , apen ( r = 0.01 ; p = 0.96 ) , and ua ( r = 0.18 ; p = 0.331 ) the modifications were not significant . this study was performed to improve the management of iugr fetuses by integrating doppler ultrasound evaluation with antepartum computerized cardiotocographic monitoring . in particular , we evaluated the modifications occurring in hemodynamic and computerized cardiotocographic parameters as indicators of a progressive adaptation in a iugr population . our choice is based on the evidence that the cctg is actually considered the most widespread noninvasive method of fetal well - being surveillance . on the other hand , doppler ultrasound is a fundamental tool to evaluate iugr fetus in relationship with fetal vascular abnormalities . decreased middle cerebral artery impedance and increased brain venous blood flow velocities these early responses are physiologically followed by late - onset doppler abnormalities such as absent / reversed umbilical artery end - diastolic velocity , absent / reversed inferior vena cava and ductus venosus waves , and umbilical vein pulsation [ 16 , 27 , 33 , 4749 ] . in particular , the longitudinal progression of abnormal doppler waveforms in the iugr deterioration of uteroplacental function is the following : elevated umbilical artery blood flow resistance and reduced umbilical vein flow volume per kilogram of fetal body weight , both of which precede the onset of a growth delay [ 27 , 50 ] . however , recently , kessous et al . have showed that ua and mca measurements have a weak correlation with perinatal outcome , that means that a physician 's decision regarding the management of a patient with suspected iugr is complicated and influenced by several variables . to date , the relationship between doppler and ctg monitoring parameters is still controversial . kaponis et al . reported that alterations of venous flow volume waveforms precede fetal heart rate decelerations and therefore offer warning signs to act before a fetal life - threatening situation occurs . for baschat , instead , placental doppler is the most powerful predictor of the clinical deterioration of iugr fetus while biophysical abnormalities may not extend beyond loss of heart rate reactivity or the decrease in the amniotic fluid index [ 52 , 53 ] . as for the time of delivery of iugr at term , a previous observational study suggests that induction of labor is associated with an increased incidence of obstetric interventions , without any neonatal benefit . instead , later randomized trials like digitat show no effect of induction on adverse neonatal outcomes . integrating doppler velocimetry with the antepartum cctg monitoring may be useful to manage pregnancies complicated by iugr and especially could help the clinician 's decision about the time of delivery . our assumptions are based on the fact that both cctg and doppler parameters were found statistically different in the three groups of study divided according to the age of gestation at the time of delivery . interestingly , we found that the three groups differ from each other also in the way of delivery , fetal ph at birth , and the apgar values at 3 minutes . finally , more important is that all the cctg and doppler parameters of the study have a significant correlation with the age of gestation , except for ua , before the 37th week ( < 34th week and from 34th to 37th week ) , and also for apen after the 37th week . approximate entropy , a mathematical approach to quantify the complexity of a system , consists in the clinical application of chaos theory . previous studies [ 55 , 56 ] had analyzed the relationship of apen with maturity of autonomous nervous system ( ans ) , thus emphasizing the relationship of a low value of apen with a lower apgar score and metabolic acidosis . in our study , we found that apen progressively and significantly decreases in the < 34th week group . since these patients delivered more frequently through an urgent caesarean section , we hypothesize that they have a greater primitive fetal compromise or the fetal compromise could be a consequence of the deterioration of maternal conditions , and this compromise is evidenced by apen . with the progress of pregnancy , apen values probably , for a better evaluation of the differences in apen in the three groups , a further investigation on other complexity indices ( sample entropy , multiscale entropy , the lempel ziv complexity , and detrended fluctuation analysis ) would be needed . these parameters previously analyzed have not been introduced yet in the clinical routine management . when comparing the cctg parameters with flowmetric indices ( distinguished into physiological and pathological ones ) , a significant difference was found . unlike ferrazzi et al . , who had observed that over 50% of fetuses delivered for abnormal fetal heart rate patterns did not have doppler abnormalities , we found , instead , that the abnormalities of cctg parameters can be correlated with doppler ones in growth restricted fetuses . the temporal trend of cctg and doppler parameters in relation to days before delivery was similar in the three groups of study , with an earlier alteration of ua , mca , and dv , in comparison with the cctg parameters , as reported by baschat and cosmi [ 53 , 59 ] . these results were in contrast with those of porto study in which a predictable progressive sequence of doppler deterioration was not found . probably , the disparity of results depends on the absence of stratification of population object of porto study . in our study , the pi of ua progressively decreased and it decreased more acutely among the two groups of patients who delivered before the 37th week . the more rapid decrease of ua - pi is consistent with a worse condition of these fetuses compared to those born after the 37th week . in fact , the ua waveform reflects placental alterations as the dimensions of the villous vascular tree , the blood flow resistance in the fetal compartment , and the relative risk for nutritional and metabolic deficiency [ 18 , 53 ] . however , this evidence did not achieve the statistic relevance in all the three groups . also mca - pi progressively reduced in the whole population , showing that the brain sparing effect was not frequently present . instead , this trend is consistent with a physiological decrease of the vascular resistance in the brain with advancing gestational age . in growth restricted fetuses , abnormal ductus venosus is considered an excellent predictor of adverse perinatal outcome [ 58 , 59 ] and a fundamental tool for choosing the optimum timing of delivery , as its abnormalities are typically associated with an increased risk for metabolic derangement or stillbirth [ 53 , 63 ] . in our study dv - pi exhibited a trend towards a decrease , which was also statistically significant compared to the progression of pregnancy . as regards the cctg parameters we found fetal heart rate significantly reducing in the three groups of study ; physiological basis is a lower maturity of parasympathetic nervous system , in comparison with a normal fhr seen in normal growth fetuses . a more marked reduction of fhr was observed in fetuses born after 37th week , maybe because of the increasing modulation by the cardiovascular function over the parasympathetic nervous system . the probability of alteration of stv increased , especially few days before delivery , suggesting that stv reflects the more acute changes in fetal condition . however , the relationship between this trend and the gestational age was statistically significant only in the two groups of patients who delivered before the 37th week . in fact , stv is considered as the best cctg indicator of fetal ans maturity , influencing not only the heart rate but also the vascular tone and the resistance cord . in our opinion , although we found important relationships between cctg parameters and doppler indices and between them and the gestational age at time of delivery in growth restricted fetuses , we still have concerns about how and when to intervene . thus , we think it is essential to detect new parameters to improve the iugr management . an effort has been performed through the development of a new method for cardiotocographic signal analysis : the phase - rectified signal averaging ( prsa ) . it is based on the synchronization of the phase of all periodic components of the noisy , nonstationary signal . prsa analyzes all periodic components of the signal , irrespective of their frequencies or characteristic time scales , and it gives an approximate distinction of the separate effects of the vagal and sympathetic nervous system [ 67 , 68 ] . to date , even if it characterizes rhythm modulations based on sympathetic activity , there is still poor evidence about the diagnostic power as a fetal surveillance method . studies evaluating the monitoring of pregnancies complicated by iugr are greatly heterogeneous , partly because our understanding of its pathophysiology is actively evolving . as a consequence , worldwide accepted guidelines about fetal growth restriction monitoring are not available and the decision to deliver a preterm iugr fetus still remains one of the great challenges in obstetrics . it is evident that iugr fetuses with placental insufficiency require antenatal testing using multiple surveillance modalities to enhance prediction of neonatal outcome and birth ph . our study , driven by the necessity of a clear combined clinical evaluation , provides a first step to a serious consideration of cctg monitoring and doppler velocimetry together as tools to detect the time of delivery in iugr fetuses before a life - threatening event can occur , achieving , at the same time , all the time possible to limit complications related to premature birth . certainly , there are questions still unanswered ; for example , how could the indices of complexity be used in the clinical routine ? what is the clinical role of less common cctg parameters , such as the spectral analysis ? and could the prsa be a method of reconciliation between doppler and cctg supporters ?

aim of the study . analyzing velocimetric ( umbilical artery , ua ; ductus venosus , dv ; middle cerebral artery , mca ) and computerized cardiotocographic ( cctg ) ( fetal heart rate , fhr ; short term variability , stv ; approximate entropy , apen ) parameters in intrauterine growth restriction , iugr , in order to detect early signs of fetal compromise . population study . 375 pregnant women assisted from the 28th week of amenorrhea to delivery and monitored through cctg and doppler ultrasound investigation . the patients were divided into three groups according to the age of gestation at the time of delivery , before the 34th week , from 34th to 37th week , and after the 37th week . data were analyzed in relation to the days before delivery and according to the physiology or pathology of velocimetry . statistical analysis was performed through the t - test , chi - square test , and pearson correlation test ( p < 0.05 ) . our results evidenced an earlier alteration of ua , dv , and mca . the analysis between cctg and velocimetric parameters ( the last distinguished into physiological and pathological values ) suggests a possible relation between cctg alterations and doppler ones . the present study emphasizes the need for an antenatal testing in iugr fetuses using multiple surveillance modalities to enhance prediction of neonatal outcome .

the growing amount of the experimental data on the single spin asymmetry ( ssa ) attracts attentions of the high energy spin community . this is understandable since the perturbative quantum chromo - dynamics ( pqcd ) predicts a zero spin effect at the asymptotic energy , while the experiments furnish up to now the opposite signatures . for example , ssa shows to be nonzero at the rhic energy of @xmath4 gev @xcite . therefore the different approaches , not so strongly justified as pqcd , but able to explain all ssa effects are needed . + in 1988 the model was proposed @xcite for interpretation of the ssa in inclusive pion productions and @xmath5 inclusive polarization . the model was able to describe the scarce data existing at that time . those experimental data came up from the unpolarized beams striking the polarized target and such experiments suffer from the poor statistical accuracies . since later a lot of new data were published and mostly from the interaction of the polarized beams with pure hydrogen target . recently the polarized relativistic heavy ion collider ( prhic ) becomes operational and the first data on the ssa for inclusive @xmath6 were published @xcite . the proza experiment at ihep , protvino , produced for the first time the data on ssa in the polarized proton target fragmentation region using unpolarized proton and pion beams . + the main goal of this article is to apply the chromo - magnetic string model ( cmsm ) of the paper @xcite to the new experimental data on the inclusive pion asymmetries . the cmsm offers a simple analytical expression for ssa description . the original paper was devoted mostly to the interpretation of the ssa in inclusive @xmath6 production . in current paper we extend the cmsm to the description of the ssa in the inclusive charged pion production too . + in section 1 we remind the main features of cmsm according to @xcite . the formulae of cmsm are specified for two distinct kinematic regions : the central ( cr ) and beam fragmentation ( bf ) region . section 2 describes the application of the model to the cr , while the section 3 is devoted to the bf region . also in section 3 we expand the model to the ssa in the inclusive charged pion productions . the unique data of e704 experiment on the ssa obtained with the polarized antiproton beam are analyzed too in scope of the isotopic spin and charge conservations . in summary we outline the successes and fails of the cmsm in description of the ssa in inclusive pion production at high energy . we make some predictions and indicate the possible improvements of the cmsm model . the basis of this model is following . after collision of two hadrons the color tube ( string ) is stretched between them . in simple case this tube contains the flux of the chromo - electric field . but such a system is not stable . in order to make it stable the chromo - magnetic field should circulate around this tube . the interaction of this field with the color magnetic moment of the polarized quark leads to a kick transverse to the string axis . this kick depends on the spin orientation of the polarized quark . the estimate of this kick gives a magnitude of order @xmath7 gev / c @xcite . if we introduce the invariant differential cross section @xmath8 for polarized quark asymmetry we get the relation @xmath9 where ( + ) and ( - ) arguments in @xmath10 mean the up and down direction of the quark polarization . since @xmath11 , where @xmath12 is a transverse momentum of the final pion to which the polarized quark fragments we get the following left - right asymmetry in the quark emission @xmath13 here b is a slope parameter of @xmath10 as it is defined in standard way . @xmath14 the general formula for description of the ssa can be expressed in the following form @xmath15 here @xmath16 is a polarization of an initial quark , carrying a portion x of the initial polarized proton momentum , @xmath17 is so called a quark `` analyzing power '' defined above ( [ qas ] ) ; w(x ) presents a fractional contribution of a channel of interest in parton - parton interactions . + the transverse quark polarization ( transversity ) , @xmath16 , is related to the spin dependent structure function @xmath18 measured in deep inelastic scattering ( dis ) . unfortunately this function has no parton interpretation . for the @xmath19 polarized on mass - shell quark @xmath20 . on the other hand it looks reasonable to expect that the x - behavior of @xmath16 is similar to that of @xmath18 . note that the present data @xcite indicate the threshold like form of the function @xmath18 which becomes very small for @xmath21 . similar effect is seen in experimental data for ssa in beam fragmentation region ( see next chapters ) . therefore such effect should be included in a more precise parametrization of @xmath16 in future . since at moment the transversity can not be directly extracted from experimental data one needs the theoretical inputs . according to the non - relativistic quark model ( nrqm ) the transversity may be taken in the following way @xmath22 so the nrqm predicts distinct effects for the pion ssa . first , the sign of asymmetry is positive for @xmath23 , while it is negative for @xmath24 . second , the magnitude of asymmetry is expected to be higher for the @xmath25 , than for @xmath6 and @xmath24 . these predictions are in general compatible with experimental data , though some deviations may happen . + another theoretical inputs can be taken from paper @xcite which aimed to explain the `` spin crisis '' by accounting the pion cloud around the proton . starting with nrqm , after account for pion loops correction one gets @xmath26=0.79 ( the sum for two u - quarks ) , and @xmath27=-0.31 corresponding to @xmath28 . in such a case we can take @xmath29 and @xmath30 leading to @xmath31 comparing ( [ ansr ] ) to ( [ nrqmp ] ) one can see that the difference is essential only for @xmath24 and this fact will be taken into account at comparisons of the calculated ssa with experimental data . + @xmath32 may depend on @xmath33 which is a feinman parameter , on @xmath12 which is a transverse momentum of pion , and on @xmath34 which is a square of the total energy in the center of mass system of colliding particles . + the invariant differential cross section is assumed to be measured before or simultaneously with ssa . + the general expression for weighting factor depends on the parton distribution function @xmath35 and parton fragmentation function @xmath36 ( a - parton flavor ) . assuming that the polarization information may be carried mostly through the polarized quark q and much less by gluons we get the weighting ( or asymmetry diluting ) factor through the following expression @xmath37 assuming that the main contribution comes from @xmath38 ( for @xmath39 ) and from @xmath40 ( for @xmath41 ) scattering via the t - channel gluon exchange between the gluon @xmath42 from unpolarized nucleon and quark @xmath43 or gluon @xmath44 from the polarized proton the contributions from quark and gluon may be written as @xmath45 where the color factors @xmath46 and @xmath47 , z is a fraction of the polarized quark momentum carried by the final hadron . + the parton and gluon distribution functions were taken in the forms @xmath48 the fragmentation functions for three types of inclusively produced pions were taken in the forms : @xmath49 the conservation of the isotopic spin and charge in parton interaction leads to the relations @xmath50 the practical applications of these relations will be given below in appropriate places . + the weighting factor ( [ wf ] ) was calculated using the relations ( [ qgcs ] ) , ( [ pdf ] ) , and ( [ pff ] ) . the final version of function w(x ) for different pions may be approximated by @xmath51 where c is:@xmath52 for @xmath25 , @xmath53 for @xmath6 , and @xmath54 for @xmath24 . + as it is seen from relations ( [ an ] ) and ( [ wf+-0 ] ) the analyzing power is calculated from @xmath55 without any free parameter . + at lower energy , small @xmath12 and @xmath33 one may expect the significant contributions to the pion yields from resonance productions @xcite . therefore we arbitrary selected experimental data with @xmath56 10 gev to avoid in some extent this problem . at present we know 3 pieces of the published data on the ssa for inclusive @xmath6 production in the central region ( no data for charged pions ) . they are : 1 . inclusive ssa for reaction @xmath57 experiment e704 at fermilab measured this reaction at 200 gev / c . kinematic region : @xmath58 , @xmath59 @xcite . + 2 . inclusive ssa for reaction @xmath60 experiment e704 at fermilab measured this reaction at 200 gev / c . kinematic region : @xmath58 , @xmath61 @xcite . inclusive ssa for reaction @xmath62 experiment proza - m at ihep , protvino , measured this reaction at 70 gev / c . kinematic region : @xmath63 @xcite . + in following we discuss these data in listed above order . + 1 . in e704 experiment up or down ( to the horizontal plane ) polarized proton beam of 200 gev / c striked the unpolarized proton target . the inclusively produced @xmath6-s were detected by the electromagnetic calorimeters around the central region , that is , at the @xmath6 emission angle of @xmath64 in c.m.s . since the experimental invariant differential cross section , @xmath10 , is almost exponential in function of @xmath12 its slope parameter b is practically constant . for example , at 200 gev / c the slope parameter b=(4.19@xmath65 @xcite . then the quark analyzing power , @xmath66 . + according to the previous discussions ( [ nrqmp ] ) and ( [ ansr ] ) we take the transversity @xmath67 , constant factor @xmath68=0.64 ( [ wf+-0 ] ) and inserting all above relations into ( [ an ] ) we got the final result for @xmath6 asymmetry in the central region @xmath69 one can see several consequences of this formula ( [ anf ] ) . first , it is scaled on argument x= @xmath70 assuming that the slope parameter is constant . second , it becomes zero at x=0 mostly due to a quark polarization and in some extent due to the gluon contribution ( second term in denominator ) . third , when x approaches to one asymmetry increases as linear function of x. all these behaviors remind the corresponding experimental asymmetry . + the result of the model prediction according to the formula ( [ anf ] ) is presented in fig.1 by the solid line . this prediction is consistent with the experimental data at 200 gev / c . the second group of data is relevant to the ssa in inclusive @xmath6 production by the polarized antiproton beam of 200 gev / c ( e704 experiment ) ( [ appocr ] ) @xcite . this reaction differs from ( [ ppocr ] ) by charge of quarks , that is , all quarks in polarized proton are replaced by the corresponding antiquarks in polarized antiproton . therefore the charge conservation requires the equality of the ssa s in these two reactions , namely @xmath71 as seen ( fig . 1 ) this conclusion is consistent with the experimental data in frame of error bars . third piece of new data @xcite is relevant to the reaction ( [ ppt70 ] ) . the data were taken at 70 gev / c unpolarized proton beam with polarized proton target . they are presented in fig.1 with opposite sign of asymmetry ( to make a comparison to the polarized beam case ) . the expression for asymmetry at 70 gev / c deduced from the cmsm looks like @xmath72 in comparison to ( [ anf ] ) there are two changes . first is relevant to the energy difference and second- to the different slope parameters . at 70 gev / c this parameter b=@xmath73 according to @xcite . the result of calculation is presented in fig.1 by the dashed line . in this case one can see a good consistency of prediction and experimental data . in order to check the quantitative predictions of the cmsm one needs much better statistics . @xmath74 , @xmath4 gev ( phenix experiment at rhic ) . at moment there are no data on the analyzing power of this reaction at @xmath4 gev . but phenix collaboration recently published the precise data on the invariant differential cross section of this reaction for @xmath75 gev / c region at pseudorapidity @xmath76 @xcite . this cross section was parameterized by authors in the following form @xmath77 here @xmath78 , @xmath79=1.219 gev / c and n=9.99 . now we can calculate the slope parameter for the phenix invariant differential cross section @xmath80 it is seen from ( [ slope1 ] ) that b(@xmath12 ) decreases with growth of @xmath12 as @xmath81 and leads to the decrease of asymmetry at large transverse momentum . this trend is similar to one stemming out at the lower initial momentum ( @xmath82 200 gev / c ) @xcite . the @xmath10 at momenta 100 and 200 gev / c was presented in the following form @xmath83 the fit to the experimental data leads to the values : @xmath84 , @xmath85 . therefore one can find the slope parameter @xmath86 the slope parameter at phenix ( [ slope1 ] ) decreases in the same way in function of @xmath12 as the slope parameter at around e704 energy ( [ slope2 ] ) indicating on the independence of the slope parameter from the initial energy at @xmath87=20 - 200 gev energy region . + one can make the prediction for asymmetry in the above reaction for phenix . it seems very small , less than 1% . we hope to see soon the experimental data from rhic on @xmath88 . + concluding the discussions of the ssa in central region we note that better precisions in @xmath89 of order @xmath90 are needed for testing the cmsm . in this domain at energies @xmath91 10 gev there are the following pieces of data : 1 . the star result on the ssa in reaction @xmath92 at @xmath87=200 gev / c . kinematic domain of measurement : @xmath93 @xcite . 2 . the e704 result on the ssa in reaction @xmath92 at 200 gev / c . kinematic domain : @xmath94 @xcite . 3 . the e704 result on the ssa in reaction @xmath95 at 200 gev / c . kinematic domain : @xmath96 @xcite . 4 . the e704 results on the ssa in reaction @xmath97 at 200 gev / c . kinematic domain of measurements : @xmath98@xcite . 5 . the e704 results on the ssa in reaction @xmath99 at 200 gev / c . kinematic domain of measurements : @xmath100 @xcite . all listed above experimental data are shown in fig.2 and fig.3 . + the expression for asymmetry ( [ an ] ) is still correct , as well as for the weighting factor w(x ) . the main change consists in replacing the argument x by @xmath33 , which presents now the portion of momentum acquired by hadron in the fragmentation of polarized quark . ssa may be written in the following way ( see ( [ an ] ) ) @xmath101 the factor c was defined earlier ( see([wf+-0 ] ) ) . + in order to calculate @xmath102 we must know the slope parameter b defined earlier ( [ bsl ] ) for each reaction at the appropriate kinematic domain . in following we discuss point by point the above experimental data on ssa s in the beam fragmentation region . star made a measurement of ssa and @xmath103 ( invariant differential cross - section ) at @xmath87=200 gev and the pseudorapidity @xmath104 . in order to extract the slope parameter the @xmath105 measured at the same experiment as function of @xmath33 was presented as the exponential function of @xmath12 and a fit to the data resulted in the slope parameter b=@xmath106 with @xmath107 at number of points = 5 . sure the fit may be improved by adding a new parameter quadratic in @xmath12 but for our goal the linear approximation in @xmath12 is acceptable . + so the final expression for @xmath108ssa at @xmath87=200 gev looks like @xmath109 the result of calculation is shown in fig.2 by the dotted line and it is consistent with the first star experimental data . since the e704 collaboration did not make the direct measurement of the invariant differential cross section simultaneously with ssa measurement at 200 gev / c we took such data from paper @xcite . in this paper the @xmath10 was measured in the interval of 50 - 400 gev / c initial proton momentum and for the different laboratory angle of the photon emission @xmath110 . the measured photon spectrum was converted to @xmath111 by applying the sternheimer s method . the transverse momenta of @xmath6 were in interval 0.3 - 4.0 gev / c . the closest to our kinematic domain are data at laboratory @xmath6 production angle @xmath112=30 mrad . we took data in the region @xmath113 . by using the exponential function with slope parameter b we found by fit that @xmath114 . for 9 experimental points @xmath115/d.o.f.=0.7 . using the relation @xmath116 the @xmath33 region for experiment was defined as 0.03 - 0.27 . in frame of these data it is impossible to go farther in @xmath33 . + taking the quark polarization as @xmath117 the final formula for ssa at 200 gev / c ( e704 experiment ) for @xmath6 is @xmath118 the result of calculation is presented in fig.2 as a solid line . one can see a qualitative consistency between the model prediction and the data of e704 experiment . + 3 . in the same fig.2 we present the ssa data for reaction @xmath119 at 200 gev / c . the model prediction is simplified by using the relation ( [ pi0 ] ) which is a consequence of transformation from quarks to antiquarks . as seen from fig.2 there is a good consistency of model prediction ( solid line ) with experimental data . figure 3 presents the experimental data from e704 experiment on the ssa for the inclusively produced pions at 200 gev / c in the following reactions : @xmath120 for calculation of the quark analyzing power , @xmath121 , we must estimate the slope parameters b@xmath122 for positive and b@xmath123 for negative pion productions . this task was done by using the data from paper @xcite . the invariant differential cross - section was taken at @xmath124 gev , closest to e704 data . the slope parameters were estimated by taking two values of @xmath125 = 0.82 gev / c and @xmath126 = 1.42 gev / c and averaged over region @xmath127 . finally we took @xmath128=5.55 gev@xmath129 and @xmath130=5.33 gev@xmath129 . so the expression for @xmath25 ssa taking @xmath131 looks like @xmath132 prediction of this formula for ssa in inclusive @xmath25 production by polarized protons is presented in fig . 3a by the solid line . data ( closed circles ) confirm this prediction fairly well excluding the region @xmath1330.4 . + fig.3b shows the ssa for inclusive @xmath24 production in pp collisions at 200 gev / c . according to the cmsm taking @xmath134 the following relation for @xmath24 ssa can be written @xmath135 following the non - relativistic quark model we assumed the negative sign of the d - quark polarization . as seen from fig.3b the cmsm prediction ( solid line ) follows qualitatively the experimental data ( closed circles ) but it does not give a quantitative agreement . a better description of ssa at the large @xmath33 furnishes the dotted line corresponding to the relation @xmath136 stemming out from paper @xcite . but in both cases the model needs some improvements in order to describe better the smallest @xmath33 region . fig.3c presents the ssa versus @xmath33 for inclusive @xmath6 productions by the polarized proton ( closed circles ) and antiproton ( open circles ) beams . as seen from this fig.3c the charge conjugation rule ( [ pi0 ] ) is well respected by the experiment . for ssa in the inclusive charged pion productions the following charge conjugation rule should be respected @xmath137 according to this relation one can predict the inclusive charged pion asymmetries produced by the polarized antiproton beam without any free parameter . the comparison of model prediction with experimental data is illustrated in fig.3 . the solid lines are model predictions . the experimental data for pp - collisions are shown by the closed circles , while data for @xmath138 collision are indicated by the open circles . relation ( [ anbpp ] ) is consistent with data in general ( fig.3 ) but there are the drastic discrepancies in some cases which are not yet understood . for example , fig.3a shows , that the experimental data violate the rule ( [ anbpp ] ) , while model gives a fairly well description of the ssa for @xmath25 production . in fig.3b the model ( [ ansr ] ) gives a better description of data than parametrization ( [ nrqmp ] ) . the data in fig.3c are consistent with expectation and the cmsm gives a good description of ssa . the fig.3d , 3e , and 3f show the @xmath12 dependencies of the ssa for @xmath139 inclusively produced by protons and antiprotons . in the explicit form such dependencies were presented in the original papers only for reactions @xmath140 @xcite ( fig.3d and fig.3e , open circles ) . other figures were restored by us using the tables of data in the original papers @xcite , @xcite , and @xcite . in function of @xmath12 all ssa are consistent with the charge conjugation rule ( compare the closed and open circles in fig.3d , 3e , and 3f ) . the solid lines are predictions of the cmsm . these lines were calculated by using the relation @xmath141 deduced from the tables of data in the original papers . constants a and b were defined by fit for each pair of ssa as they are presented in figures . the consistencies between data and predictions are reasonable , though in fig.3d and fig.3e the discrepancies are seen at low @xmath12 between model prediction and the experimental data . at such low @xmath12 some non - perturbative interaction ( in particular , instanton induced ) may affect our predictions by changing the weighting factor w(x ) and/or by flipping quark helicity . concluding this section we note that in general the cmsm gave the qualitative description of most of the ssa effects in a whole measured kinematic domain . nevertheless it fails in the interpretations of the one feature of ssa , namely , the evidence of @xmath142 in the interval @xmath143 . this is illustrated by the @xmath144 ( see fig.3b ) and @xmath145 ( see fig.3d ) . this event might be related to some threshold effect like resonance production . we propose a chromo - magnetic string model producing the simple analytic expressions for the single spin asymmetries of inclusive charged and neutral pion productions . it describes all known experimental data in the central and beam fragmentation regions . the following experimental facts are naturally explained on the basis of the parton model , conservation of the charge and the invariance of the parton interaction with respect to the charge conjugation : @xmath146 and @xmath147 . the qualitative descriptions of the @xmath12 , @xmath33 and energy dependencies of the single spin asymmetry seem reasonable . the cmsm should be applied beyond the domain of resonance production and out of the threshold phenomena . + to improve the model one has to use the quark and gluon distributions ( @xmath148 ) given by the global parton analysis and the fragmentation functions ( @xmath149 ) measured in @xmath150-annihilation together with the nlo expressions for the hard parton - parton scattering cross sections . this will provide a more precise weighting factor @xmath151 ( [ wf ] ) . + next ( and more important ) is to use a more realistic formula for the quark polarization @xmath16 . unfortunately we can not use the spin dependent structure function @xmath18 measured in the deep inelastic scattering ( dis ) directly . this function has no parton interpretation and for 100@xmath152 polarized on mass - shell quark @xmath18=0 . therefore , the value of @xmath18 measured in dis is expected to be smaller than @xmath16 . on the other hand it looks reasonable to choose @xmath153 with such a coefficient c that ( according to `` spin crisis '' ) the whole polarization carried by valence quark will be about 1/4 of the incoming proton polarization . in this way , thanks to the @xmath154 behavior of @xmath18 , we hope to reproduce the behavior of ssa observed in the data at @xmath155 . + we expect that the coming soon data from the polarized rhic will test our model more precisely . + we would like to express our thanks to l. bland , yu.v . kharlov , v.v . mochalov and d.v . sidorov for help and useful discussions .

an attempt is made to interpret the various existing experimental data on the single spin asymmetries in inclusive pion production by the polarized proton and antiproton beams . as the basis of analysis the chromo - magnetic string model is used . a whole measured kinematic region is covered . the successes and fails of such approach are outlined . the possible improvements of model are discussed . * experimental data on the single spin asymmetry and their interpretations by the chromo - magnetic string model * s.b . nurushev@xmath0 and m.g . ryskin@xmath1 @xmath2 institute for high energy physics , 142281 protvino , moscow region , russia + @xmath3 petersburg nuclear physics institute , 188300 gatchina , st . petersburg , russia

bright supernovae occurring in external galaxies afford a unique opportunity to probe the structure of interstellar gas in the galactic halo as well as in the supernova host galaxy through high - resolution , absorption - line spectroscopy . in recent decades , a number of supernovae have been used in this manner , providing insights on the characteristics of gaseous material in nearby galaxies , in the intergalactic medium , and in galactic high - velocity clouds , or hvcs ( e.g. , jenkins et al . 1984 ; dodorico et al . 1989 ; steidel et al . 1990 ; meyer & roth 1991 ; bowen et al . 1994 ; vladilo et al . 1994 ; ho & filippenko 1995 ; king et al . 1995 ; bowen et al . 2000 ) . the recent discovery of the type iib sn 2011dh in m51 ( arcavi et al . 2011 ; see also griga et al . 2011 ; silverman et al . 2011 ) , which reached a maximum brightness of @xmath2 , presented us with the chance to acquire high - resolution spectra to search for interstellar absorption lines in the direction of the supernova . this particular supernova is significant in that it is the third such object to be detected in m51 ( the whirlpool galaxy ; ngc 5194 ) within the past 20 years , following the discoveries of sn 2005cs ( a type iip ) and sn 1994i ( a type ic ) . ho & filippenko ( 1995 ) obtained high - resolution observations of sn 1994i , finding numerous strong absorption components of na i d associated with interstellar gas in m51 , along with components of more moderate strength , some identified with the disk of our galaxy and others likely identified as hvcs belonging to either our galaxy or m51 . in this letter , we report on high - resolution observations of na i d and ca ii h and k absorption along the line of sight to sn 2011dh , which exploded at an apparent position @xmath3 e and @xmath4 s of the nucleus of m51 ( van dyk et al . this corresponds to a projected distance of 6.1 kpc , assuming the distance to m51 is 8.0 mpc ( as listed in the nasa / ipac extragalactic database ) . the positions of sn 2011dh and sn 1994i ( which was located @xmath5 or 0.7 kpc from the nucleus ) are separated by only @xmath6 on the sky . thus , by comparing our results with those of ho & filippenko ( 1995 ) , we are able to simultaneously probe small - scale structure in the galactic disk and halo and galactic - scale structure in the interstellar medium ( ism ) of m51 . our data were acquired with the astrophysical research consortium ( arc ) 3.5 m telescope at apache point observatory ( apo ) , using the echelle spectrograph , which provides complete wavelength coverage in the range 380010200 with a resolving power of @xmath7 ( @xmath8 km s@xmath0 ) . three 30 minute exposures of sn 2011dh were obtained on 2011 june 9 , one on 2011 june 13 , and three more on 2011 june 20 ( all dates are given in ut ) , during which time the supernova increased from @xmath9 to @xmath10 . evidently , our observations on june 20 were made shortly before maximum brightness . the bright , nearby star @xmath11 uma ( b3 v ; @xmath12 ) also was observed on june 9 and june 20 to aid in the removal of telluric absorption lines in the spectrum of sn 2011dh . lines associated with m51 ; see figure 2 ) , but that the removal procedure yields the appropriate relative strengths of these lines compared to the weaker lines of the doublet . strong night sky emission lines are identified with the symbol @xmath13 . these were removed before proceeding with profile fitting.,scaledwidth=45.0% ] the raw exposures were reduced using a semi - automated pipeline reduction procedure , which employs standard iraf routines for bias correction , cosmic - ray removal , scattered - light subtraction , one - dimensional spectral extraction , flat - fielding , and wavelength calibration . the reduction procedure is based on the iraf data reduction guide for the arc echelle spectrograph written by j. thorburn . atmospheric absorption lines were removed from individual , calibrated exposures of sn 2011dh with the iraf task telluric using @xmath11 uma as the telluric standard . this procedure accounts for differences in airmass as well as in the abundances of telluric species between the standard spectrum and the exposure being corrected ( see figure 1 for a demonstration of the effectiveness of the telluric line removal procedure in the vicinity of na i d ) . the corrected spectra were then shifted to the reference frame of the local standard of rest ( lsr ) and the individual exposures were co - added to produce a final , high signal - to - noise ratio ( s / n ) spectrum of sn 2011dh . the s / n ranges from @xmath1110 near 5900 to @xmath140 near 3900 . the only interstellar absorption features positively identified in our final spectrum of sn 2011dh are those of the na i d ( d@xmath14 @xmath155895 ; d@xmath16 @xmath155889 ) and ca ii h ( @xmath153968 ) and k ( @xmath153933 ) doublets . the overlapping echelle orders containing these lines were combined to improve the s / n and the resulting spectra were normalized to the relatively featureless continuum . as seen in figure 2 , we detect na i and ca ii absorption both from the milky way ( near @xmath17 km s@xmath0 ) and from m51 ( near the m51 systemic velocity of @xmath18 km s@xmath0 ; walter et al . 2008 , applying a heliocentric - to - lsr velocity correction of 12 km s@xmath0 ) . given the overall weakness of these features , it is not surprising that other optical absorption lines , such as k i @xmath19 , ca i @xmath20 , ch@xmath21 @xmath22 , and ch @xmath23 , are not detected . however , we are unable to search for k i @xmath19 absorption at the redshift of m51 due to the presence of strong night sky emission lines at the same wavelengths . before analyzing the final combined spectrum of sn 2011dh , we compared the nightly coadded spectra from june 9 and june 20 the two nights on which we have the best s / n due to our having obtained multiple exposures in order to search for variations in the absorption profiles . a variable component might be expected if the absorption originates in circumstellar material associated with the progenitor of sn 2011dh , which gets swept up in the supernova blast wave . upon careful inspection , we find no evidence for significant variation in any of the na i or ca ii components . thus , the results of this paper are based solely on the analysis of the combined spectrum . the interstellar na i and ca ii absorption profiles toward sn 2011dh were analyzed by means of the profile fitting routine ismod ( y. sheffer , unpublished ) , which fits multiple voigt components to the observed spectrum , convolving the intrinsic line profile with an instrumental profile , assumed to be gaussian in shape . using a simple rms - minimizing technique , ismod determines best - fit values for the velocity , @xmath24-value , and column density of each component . since the absorption features are relatively weak , line saturation is not a major concern for these data . only the na i component near @xmath25 km s@xmath0 , which presumably arises from gas within the milky way , shows significant optical depth at line center . for this component , the ratio of the na i d@xmath16 to d@xmath14 equivalent widths is 1.2 ( as opposed to 2.0 in the optically thin case ) and implies a doppler width of @xmath26 km s@xmath0 . in order to derive an accurate column density for this mildly - saturated component , the @xmath24-value was held fixed at 2.1 km s@xmath0 in the profile fit for both the d@xmath16 and d@xmath14 lines . our analysis of ca ii absorption toward sn 2011dh rests mostly on the ca ii k line , because the weaker h components are strongly affected by noise in the spectrum . we initially fit the na i d and ca ii k profiles by focusing on the prominent components seen in both species . ultimately , we were required to include additional components to account for the extra ca ii absorption surrounding the main galactic component and to fill in gaps between the stronger na i and ca ii components associated with m51 . to aid in the process of decomposing the blended profiles , the @xmath24-values were constrained to fall within certain limits consistent with ultra - high resolution surveys of the galactic ism ( e.g. , welty et al . 1994 , 1996 ) . we note , however , that @xmath24-values derived in this study are more appropriately referred to as `` effective '' @xmath24-values since at our resolution ( @xmath27 km s@xmath0 ) unresolved substructure almost certainly exists in the data . the results of fitting the ca ii k line were then applied to ca ii h to check for consistency , holding the relative velocities , @xmath24-values , and fractional column densities fixed . table 1 presents the na i and ca ii equivalent widths ( and 1@xmath28 uncertainties ) derived from our profile fits to these lines ( see figure 2 ) . in table 2 , we give the fitted column density and @xmath24-value of each na i d and ca ii k component along with the mean lsr velocity . in most cases , the uncertainties in @xmath29 reflect the uncertainties in @xmath30 , which are based on the rms deviations in the continuum and the widths ( fwhm ) of the absorption features . these uncertainties effectively include both photon noise and errors in continuum placement . for the na i component near @xmath25 km s@xmath0 , the column density uncertainties also include the effects of varying the @xmath24-value within the range allowed by the errors in the doublet ratio . final na i column densities were determined by taking the weighted mean of the column densities derived from the d@xmath16 and d@xmath14 lines , while for ca ii we simply adopted the more precise results from ca ii k. the agreement with column densities from ca ii h is at the 10% level or better . the last column of table 2 presents the @xmath29(na i)/@xmath29(ca ii ) ratio ( or limits on the ratio ) for each of the milky way and m51 components . we find total na i d@xmath16 and d@xmath14 equivalent widths of @xmath31 m and @xmath32 m , respectively , for the features associated with m51 . these values are in good agreement with those reported by arcavi et al . ( 2011 ) , which were obtained from keck high resolution echelle spectrometer data . as those authors noted , such weak absorption in the na i d lines indicates very little host galaxy extinction in the direction of sn 2011dh , probably less than the galactic foreground extinction , which corresponds to an interstellar reddening of @xmath33 ( schlegel et al . an exciting aspect of this investigation is our ability to compare high - resolution optical spectra of two supernovae from the same external galaxy , allowing us to examine structure in the galactic disk and halo at small angular scales as well as in the ism of m51 at scales of several kiloparsecs . a comparison between our na i d results for sn 2011dh and those of ho & filippenko ( 1995 ) for sn 1994i reveals both similarities and differences between the two lines of sight , which are separated by only @xmath6 on the sky ( near galactic coordinates @xmath34 , @xmath35 ) . both investigations find a strong galactic na i component at @xmath36 km s@xmath0 ( system 1 in the nomenclature of ho & filippenko 1995 ) , which likely originates from relatively nearby gas , since there is very little difference in the na i column density between the two sight lines . the @xmath29(na i)/@xmath29(ca ii ) ratio for this component ( @xmath37 ) is indicative of a high degree of ca depletion , a characteristic of cool diffuse clouds at relatively low velocities ( siluk & silk 1974 ; hobbs 1983 ) . indeed , the lsr velocity of the component is consistent with the expected velocity of gas participating in galactic rotation at @xmath34 ( e.g. , sembach & danks 1994 ) . we do not detect the weaker galactic component at @xmath38 km s@xmath0 ( system 2 in ho & filippenko ) in na i , but do observe this component , and other galactic components at more negative velocities , in ca ii . these additional galactic components have only upper limits on @xmath29(na i)/@xmath29(ca ii ) suggesting low ratios ( @xmath39 ) and so presumably trace warmer gas , where ca depletion is not as severe or where much of the neutral na has been destroyed through collisional ionization . along with absorption components identified as belonging to the milky way , we find several components in na i and ca ii toward sn 2011dh with @xmath40@xmath41 km s@xmath0 . these are almost certainly associated with interstellar gas in m51 , as are the much stronger na i components that ho & filippenko ( 1995 ) detect in the spectrum of sn 1994i with @xmath42@xmath43 km s@xmath0 ( their systems 614 ) . since sn 1994i occurred near the nucleus of m51 , while sn 2011dh exploded in one of the outer spiral arms ( see figure 1 in arcavi et al . 2011 ) , the large difference in total na i column density between the portions of m51 probed by the two lines of sight is understandable . like many spiral galaxies , the inner region of m51 exhibits only weak h i 21 cm emission ( e.g. , rots et al . however , maps of co 2@xmath441 and 1@xmath440 emission ( rand & kulkarni 1990 ; schuster et al . 2007 ) indicate that the nucleus is rich in molecular gas , accounting for the higher na i column density in that region . the strongest m51 component in our na i and ca ii data for sn 2011dh has a velocity of @xmath45 km s@xmath0 ( component 7 ) , which is close to the adopted recessional velocity of the galaxy of 468 km s@xmath0 . at the apparent position of sn 2011dh , however , the velocity exhibited by disk gas should be significantly higher than the systemic velocity due to the inclination of m51 ( @xmath46 ; tamburro et al . the velocity field ( moment 1 map ) provided by the h i nearby galaxy survey ( things ; walter et al . 2008 ) indicates a mean h i velocity of @xmath47 km s@xmath0 at the supernova position . the corresponding h i emission profile exhibits a single narrow ( fwhm @xmath48 18 km s@xmath0 ) peak at this velocity , with no prominent emission at the velocity of component 7 ( see figure 3 ) . in fact , none of the prominent na i or ca ii components in our spectra appear to coincide with the peak in h i emission , suggesting that the supernova lies just in front of the bulk of the h i disk . adopting the mean h i velocity from things as the local disk velocity at the position of the supernova , the observed absorption from m51 ranges from @xmath49 km s@xmath0 ( component 6 ) to @xmath50 km s@xmath0 ( component 13 ) . the velocity dispersion in na i is @xmath139 km s@xmath0 , and @xmath133 km s@xmath0 in ca ii . both are larger than the h i velocity dispersion , which is @xmath120 km s@xmath0 at the supernova position ( based on the things moment 2 map ) . the fact that we are detecting more components in na i and ca ii than are detected via h i 21 cm emission and detecting them over a broader range in velocity is most likely related to the limited sensitivity of the h i observations . the column density detection limit in things channel maps of m51 is log @xmath29(h i ) @xmath51 ( for a 3@xmath28 detection in at least two channels ; see walter et al . for comparison , the na i column densities of components 613 imply h i column densities in the range log @xmath29(h i ) @xmath52@xmath53 , indicating that much of this h i would be undetectable.(na i ) and @xmath54(h ) discussed by welty & hobbs ( 2001 ) , and the assumption that virtually all of the hydrogen is in neutral atomic rather than molecular form , as also implied by the na i column densities . by applying these relationships , we implicitly assume that the metallicity and radiation field in the m51 foreground are similar to typical galactic values . ] in contrast , the h i emission actually detected by things at the position of sn 2011dh yields log @xmath29(h i ) = @xmath55 . if the supernova were positioned behind this material , we would expect to see na i absorption with a column density approaching log @xmath29(na i ) @xmath56 . still , the @xmath29(na i)/@xmath29(ca ii ) ratios exhibited by the m51 components are similar to those seen in disk clouds of the milky way ( e.g. , sembach & danks 1994 ) and in the disks of other external galaxies that have been probed by bright supernovae ( e.g. , bowen et al . the components with higher na i column densities generally have higher @xmath29(na i)/@xmath29(ca ii ) ratios , and at least two components have @xmath29(na i)/@xmath29(ca ii ) @xmath57 , an indication that the absorption originates in relatively cool gas ( see , e.g. , bertin et al . 1993 ) . interestingly , we find similar ratios ( of order unity ) in both quiescent gas , with @xmath58 km s@xmath0 , and higher - velocity clouds , with @xmath59 km s@xmath0 , contrary to expectations based on the routly - spitzer effect ( routly & spitzer 1952 ) . thus , rather than showing evidence for enhanced grain destruction in high - velocity material , our results indicate that a similar degree of ca depletion characterizes both quiescent and high - velocity gas in the portion of m51 sampled by this particular line of sight . the higher - velocity material may not originate very far from the disk , however , since the components have @xmath60 km s@xmath0 . these velocities are similar to those of intermediate - velocity clouds ( ivcs ) in the milky way , which are usually found within @xmath15 kpc of the galactic plane ( e.g. , wakker et al . 2008 ) . typical scenarios invoked to explain the origin of galactic hvcs and ivcs include production in a galactic fountain , tidal stripping from a companion galaxy , and accretion from the intergalactic medium , among others ( see wakker & van woerden 1997 ; richter 2006 ) . since most of the galactic ivcs have solar metalicities ( wakker 2001 ; richter et al . 2001 ) , their origin can most easily be explained within the context of the galactic fountain model , in which hot gas is injected into the halo by supernova explosions and then cools and falls back onto the disk . a similar process may be responsible for the relatively cool cloud we find in the direction of sn 2011dh with a high positive velocity , which indicates that it is falling toward the disk of m51 . on the other hand , tidal interactions between m51 and its companion ( ngc 5195 ) may have played a role in generating the high velocity dispersion we observe in na i and ca ii . tidal effects may be particularly important for explaining the origin of na i components with high negative velocities , since in the outflow stage of the galactic fountain process the gas is expected to be mostly ionized ( fraternali et al . multiple processes may be occurring simultaneously . indeed , miller & bregman ( 2005 ) invoke both galactic fountain and tidal stripping scenarios to explain deep very large array observations of m51 , which reveal a number of discrete h i sources with anomalous velocities . an interesting result of ho & filippenko s ( 1995 ) study of sn 1994i was their detection of na i components at velocities intermediate between those expected for gas associated with the milky way and m51 ( i.e. , @xmath61@xmath62 km s@xmath0 ; their systems 35 ) . the authors attributed this absorption to hvcs , but could not distinguish between an origin in the galactic halo or in the halo of m51 , since the velocities of the clouds with respect to the overall systemic velocity of the galaxy to which they belong would be similar in either case . we detect no na i or ca ii absorption features in this velocity range toward sn 2011dh ( just @xmath6 away ) , indicating that if the clouds indeed have a galactic origin , they exhibit significant structure on small scales . we thank suzanne hawley for granting us director s discretionary time at apo so that prompt spectra of sn 2011dh could be obtained and john wisniewski for contributing the spectrum from june 13 . we are also grateful for the comments and suggestions provided by the anonymous referee . this research was supported by the kennilworth fund of the new york community trust . arcavi , i. , et al . 2011 , , 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@xmath82 & @xmath83 & @xmath84 + 9 & @xmath85 & @xmath86 & @xmath87 & @xmath88 + 10 & @xmath89 & @xmath90 & @xmath91 & @xmath92 + 11 & @xmath93 & @xmath94 & @xmath95 & @xmath96 + 12 & @xmath97 & @xmath98 & @xmath99 & @xmath100 + 13 & @xmath101 & @xmath75 & @xmath102 & @xmath103 + ccccccccccc + 1 & @xmath104@xmath105 & & & & & & @xmath106 & 3.8 & @xmath107 & @xmath39 + 2 & @xmath104@xmath108 & & & & & & @xmath106 & 3.8 & @xmath109 & @xmath39 + 3 & @xmath104@xmath110 & 2.1 & @xmath111 & & 2.1 & @xmath112 & @xmath113 & 3.8 & @xmath114 & @xmath37 + 4 & @xmath104@xmath115 & & & & & & @xmath106 & 2.1 & @xmath116 & @xmath39 + 5 & @xmath117@xmath118 & & & & & & @xmath106 & 2.1 & @xmath119 & @xmath39 + + 6 & @xmath120 & 2.6 & @xmath121 & & 2.6 & @xmath122 & @xmath123 & & @xmath124 & @xmath125 + 7 & @xmath126 & 2.1 & @xmath127 & & 2.6 & @xmath128 & @xmath129 & 2.1 & @xmath130 & @xmath131 + 8 & @xmath132 & 0.5 & @xmath133 & & 1.3 & @xmath134 & @xmath135 & 3.8 & @xmath136 & @xmath137 + 9 & @xmath138 & 0.6 & @xmath139 & & 0.5 & @xmath140 & @xmath141 & 3.8 & @xmath142 & @xmath143 + 10 & @xmath144 & 2.4 & @xmath145 & & 2.6 & @xmath146 & @xmath145 & 3.8 & @xmath147 & @xmath148 + 11 & @xmath149 & 2.1 & @xmath139 & & 1.4 & @xmath150 & @xmath151 & 1.2 & @xmath152 & @xmath153 + 12 & @xmath154 & 2.6 & @xmath155 & & 2.6 & @xmath156 & @xmath155 & 1.0 & @xmath157 & @xmath131 + 13 & @xmath158 & 1.4 & @xmath159 & & 1.9 & @xmath160 & @xmath161 & 2.1 & @xmath162 & @xmath163 +

we present high - resolution echelle observations of sn 2011dh , which exploded in the nearby , nearly face - on spiral galaxy m51 . our data , acquired on three nights when the supernova was near maximum brightness , reveal multiple absorption components in na i d and ca ii h and k , which we identify with gaseous material in the galactic disk or low halo and in the disk and halo of m51 . the m51 components span a velocity range of over 140 km s@xmath0 , extending well beyond the range exhibited by h i 21 cm emission at the position of the supernova . since none of the prominent na i or ca ii components appear to coincide with the peak in h i emission , the supernova may lie just in front of the bulk of the h i disk . the na i / ca ii ratios for the components with the most extreme positive and negative velocities relative to the disk are @xmath11.0 , similar to those for more quiescent components , suggesting that the absorption originates in relatively cool gas . production scenarios involving a galactic fountain and/or tidal interactions between m51 and its companion would be consistent with these results . the overall weakness of na i d absorption in the direction of sn 2011dh confirms a low foreground and host galaxy extinction for the supernova .

talking about biological ageing may be somewhat distressing , specially for those who are over forty , as are two of the authors . however , ageing is just one of the features of evolution , and to understand such an unavoidable mechanism it is necessary first to understand the paths of evolution . in fact , the concepts of evolution and ageing are connected by darwin s theory of selection of the fittest , published in 1859 . insofar that it concerns the general evolution mechanism , this famous theory states that : _ if genetically distinct individuals compete for limited resources , those more fitted to the environment will produce more offspring . random mutations mix the genes , giving rise to new genetic combinations , and at every generation natural selection eliminates the less efficient ones , in order to continuously improve adaptation_. however , since ageing is related to an age structure , the same theory concerning this subject is better enunciated as : _ a mutation endangering the life of an organism before the reproductive age is much more dangerous to the species than a mutation affecting it only late in life , when it has already produced enough offspring to warrant the perpetuation of its lineage_. in both cases , the notion of fitness , one of the most debated quantities in population genetics , first introduced by fisher @xcite and wright @xcite , seems to be closely related to the reproductive rate . selection is also related to competition , which implies that the weaker are supposed to die . thus , nature must offer a death mechanism , which turns to be the ageing process . perhaps evolution can be fully explained by darwin s theory . there is , however , a problem : where is the equation that would allow biologists , geneticists , mathematicians and even _ exotic _ physicists to understand how nature works and to publish more and more papers ? because such an equation does nt exist , different models have appeared in order to explain the origins of life and its evolution . according to luca peliti @xcite , these models can be divided into three groups . the first one concerns microevolution , that is , the evolution of individuals belonging to the same species or to closed ones . one example is the eigen model for quasispecies @xcite , described in section 2 . in such models the interaction among individuals is generally introduced through some mechanism of global competition . the second group concerns coevolution , where two or more species interact strongly in such a way that the survival of one species depends on the survival of the other . the most common problem studied with these models is the prey - predator one , presented in a quantitative way by lotka @xcite and volterra @xcite many decades ago . another example is the host - parasite interaction , which will appear later in this paper ( section 4.4 ) as one possible explanation for the evolution of sex . finally , the third group corresponds to models for macroevolution or large - scale evolution , that deal with all species alive at the same time but with no particular interacting mechanism between them . the concept of fitness for such models can not be simply related to the reproduction rate of the individuals , since each species has its own reproductive strategy . it is necessary to consider instead a continuously evolving _ fitness landscape _ , that changes whenever a species mutates or disappears . in order to survive , the remaining species are also continuously evolving , trying always to be close to the peaks of the landscape . the bak - sneppen model @xcite is one of the simplest and most famous models of this third group . it considers the dynamics of large - scale evolution as a result of a _ self - organized critical process _ , responsible for the presence of scaling laws in macroevolutionary data . if it is easy to group the different models for evolution , the same is not true when the subject is ageing . in 1990 the russians gerontologist zhores medvedev @xcite classified more than 300 theories constructed in order to explain _ the reduction of survival probability with advancing age_. fortunately , these theories can be grouped in two types : the theories of `` why '' and the theories of `` how '' . the first type tries to understand ageing through a global perspective and to explain its disparities among the species . theories of the second type search for the specific mechanisms or immediate causes of ageing , each one with a given degree of validity depending on the species . the theories of `` why '' are also divided in two groups . the first one attributes physiological unavoidable reasons for ageing , such as the harmful action of the oxygen radicals that are constantly produced in our bodies or the existence of a programmed cell death after a given limited number of cell divisions . the rate of metabolism of each species is probably the oldest example of this kind of theory . since large mammals such as elephants move slowly and live much longer than small ones , which are very active and so have a high metabolic rate , for many years it was believed that this was the explanation for the disparities in the longevity of different species . however , it was discovered that there are branches of the same species that hibernate in the northern hemisphere and live as long as those branches that inhabit the southern hemisphere . there are also some kinds of birds that have an extremely long lifetime , despite the large amount of energy they need for flying . observations like the ones above have gradually increased the importance of the second group of the `` why '' theories , that is _ the evolutionary theories _ , proposed around 1950 by peter b. medawar , george c. williams and other famous biologists ( for a review on the history of ageing theories and many of its interesting features see the special issue of la recherche , 322 , july / august 1999 ) . these are theories based in darwin s proposal of selection of the fittest @xcite . as mentioned before , an important ingredient for modeling using the evolutionary approach is to have an age structure with no reproduction during youth . one of the pioneers , and one of the simplest models using this strategy is the partridge - barton model @xcite , which considers only two age intervals , one from t=0 to t=1 for juveniles and another , from t=1 to t=2 , for adults . reproduction is possible only at ages 1 and 2 and is followed by death after age 2 . however , when only deleterious inherited mutations are considered , this model leads to population meltdown , that is , the population dies out due to the accumulation of such mutations . the penna model for biological ageing @xcite , described in section 4 , is also based on the mutation accumulation hypothesis and is now by far the most used one to reproduce and understand different aspects of real population dynamics . it deals with many age intervals and has successfully explained the catastrophic senescence of salmon ; why women live longer than men ; why does menopause exists , and other biological phenomena . besides giving results that are in agreement with the empirical gompertz law of an exponential increase of mortality with age , it does nt lead to the population meltdown mentioned above . this review is organized in the following way : the eigen model is described in section 2 , the bak - sneppen model in section 3 and the penna model and its main results in section 4 . in section 5 we present our conclusions . the eigen s quasispecies model @xcite is one of the archetypical representation of the darwin s postulates of evolution by natural selection . the model , originally developed to address the issue of explaining the origin of life on earth , describes the dynamics of populations of replicating biological macromolecules under the influence of selection and mutation mechanisms . it predicts that if mutations occur frequently enough , the target of selection will no longer be a single individual , but rather an ensemble of genetically related individuals called a _ quasispecies_. moreover , when the mutation rate surpasses a critical value , known as the _ error threshold _ , the result is a complete loss of this polymorphic genetic structure . in this section we shall restrict ourselves to eigen s first theoretical model of molecular evolution based on deterministic chemical kinetic theory ( see @xcite for a complete review of the original formulation ) . its conceptual elements and results may nevertheless be fairly well described , and perhaps even more appropriately , in the language of population genetics @xcite , in terms of the frequencies of haploid multi - locus individuals ( see @xcite for an excellent review on this subject ) . the original formulation of eigen focus on a well - defined model system : the flux reactor . it comprises basically a reaction vessel , in which biological macromolecules are continually built up out of energy - rich @xmath0 monomers ( triphosphates ) , that are required for macromolecular synthesis , and decay , after a certain time , back to their energy - deficient @xmath1 monomers ( monophosphates ) . furthermore , it is assumed that this system can exchange energy and matter with its surroundings , by regulating both the supply of energy - rich and energy - deficient monomers , as well as the total population of macromolecules . each chemical component of this reaction system consists of a reproducing macromolecule modeled as a single string of @xmath2 digits @xmath3 , with the variables @xmath4 @xmath5 allowed to take on @xmath6 different values . each of these values represents a different type of monomer used to build the molecule ( among biological macromolecules @xmath7 for nucleic acids g , a , c , t ; @xmath8 purines and pirimidines ; @xmath9 for proteins ) . it is reasonable , therefore , to ignore the genotype - phenotype distinction ; since the relevant darwinian entities are replicating macromolecules , genotype and phenotype are aspects of one and the same object , its molecular sequence ( see @xcite for a comprehensive overview ) . in this way , for one particular string ( or macromolecule , or genome ) of type @xmath10 , the various events that could happen inside the flux reactor can be visualized as the following single chemical reaction steps , @xmath11 @xmath12 @xmath13 @xmath14 in these reactions , it is assumed that the available amount of @xmath1 and @xmath0 monomers is constant . the reaction ( [ rea1 ] ) denotes the self - replication , or error - free replication , of molecule @xmath15 , and the reaction ( [ rea2 ] ) takes on the erroneous replication , or mutation , of @xmath15 that can lead to a new molecule @xmath16 . the replication matrix @xmath17 takes into account the primary structure of the macromolecules . this feature is what distinguishes this model , a sequence space model , from models of population genetics @xcite . more specifically , its elements are given by @xmath18 and @xmath19 where @xmath20 is the replication rate ( or fitness ) of molecules of type @xmath10 , which tells us how fast new @xmath15 are synthesized in the next generation , independently of whether the copies are correct or not . the parameter @xmath21 is the hamming distance between strings @xmath10 and @xmath22 , i.e. , the number of monomers or positions at which these two sequences differ . here , @xmath23 $ ] is the fidelity parameter of each monomer , i.e. , the probability of inserting the correct monomer for any position . correspondingly @xmath24 is the error rate ( or mutation rate ) per monomer , which is assumed to be the same for all monomers . thus , self - replication and mutation are represented by two autocatalitic reactions , homogeneous and heterogeneous , respectively . the chemical decomposition of the molecular specie @xmath15 is represented by reaction ( [ rea3 ] ) , so that @xmath25 is a general decay rate parameter . the reaction ( [ rea4 ] ) represents the efflux of the molecule @xmath15 by diffusion , where @xmath26 is a global diffusion flux that is assumed to be the same for all molecules . the relevant variables of this dynamical system are the concentrations of each macromolecule @xmath27 $ ] . then , inside the reactor , the concentrations @xmath28 of molecules of type @xmath29 evolve in time according to the following differential equations @xmath30 x_{i}. \label{ode}\ ] ] the quasispecies model can thus be described as a population dynamics model given by the full set of phenomenological differential equations . the equations ( [ ode ] ) , however , do not yet lead to _ competitive selection _ in our model system . moreover , in order to induce selection pressure in the system described by ( [ ode ] ) it is necessary to impose some type of restriction to it . to appreciate the effect of the competition in the model system ( that may or may not lead to selection ) , let us imagine the ideal situation where the molecular species reproduce themselves without error , so that @xmath31 and @xmath32 @xmath33 . in this case , equations ( [ ode ] ) become @xmath34 x_{i}. \label{ode1}\ ] ] it is trivial to see that the solutions for the molecular concentrations are exponentials if @xmath35 is constant . thus , if there are @xmath36 distinct species of molecules inside the reactor , the concentration of all species with replication rate @xmath37 @xmath38 grows exponentially as time goes by , while all those with @xmath39 die out . in this scenario , there is no competition and thus no selection . this behaviour of _ segregation _ in the model is show schematically in figure [ fidom1](a ) for the case of five types of binary molecules ( @xmath8 , @xmath40 ) , all with the same frequencies at @xmath41 . in this case of replication without error , we can now subject the molecular population inside the reactor to some form of global constraint . this can be made by keeping the total population of molecular species constant , @xmath42 . for this purpose the global dilution flux @xmath26 will be adjusted in time so as to keep pace with the increase in total molecular concentration , i.e. , it will be determined by the condition @xmath43 . therefore , the global flux of molecules inside the reactor must satisfy the condition @xmath44 now , with this equation for @xmath35 , the set of differential equations ( [ ode ] ) and ( [ ode1 ] ) is non - linear . in figure [ fidom1](b ) the temporal behavior of the same molecular populations of example of figure [ fidom1](a ) is schematically shown when we constrain the system to have a constant population . in fact , as @xmath35 increases due to the constant population condition , a higher number of molecules is segregated , and only the one with the highest productivity will survive . in the stationary state of this competition , the winner is called the _ master sequence _ ( @xmath45 ) and the stationary state of this system is termed _ selection equilibrium_. the molecular selection process is , therefore , an environmental effect , through a constraint imposed on molecular population , and always leads to an unambiguous selection decision . let us discuss briefly the more general case , described by equation ( [ ode ] ) . if we allow for erroneous replication ( @xmath46 ) , considerations similar to the ones above lead to the following condition on @xmath35 @xmath47 the selection equilibrium solution of ( [ ode ] ) can be found in terms of the eigenvalues and eigenvectors of the replication matrix @xmath17 . if we define the vector @xmath48 , where the components represent the relative concentrations ( or frequencies ) of each molecular species in the population , @xmath49 , we can write @xmath50 where the diagonal elements of @xmath17 were modified to @xmath51 ( see the appendices of @xcite for details on how to transform the non - linear system described by ( [ ode ] ) and ( [ prod1 ] ) in a linear one ) . then , we define a quasispecies precisely as the dominant eigenvector @xmath52 associated to the largest eigenvalue @xmath53 of the replication matrix @xmath54 . this eigenvector describes the exact population structure of the population : each mutant @xmath15 is present in the quasispecies with frequency @xmath55 ( @xmath56 ) . note that the largest eigenvalue is exactly the average replication rate of the quasispecies , @xmath57 . in this scenario , the frequency of a given mutant within the quasispecies does not depend on its replicative value alone , but also on the probability with which it is produced due to erroneous replication of others molecular species . moreover , depending on the mutation rate @xmath24 , the master sequence and some ( or all ) mutants coexist as a quasispecies . then , one of the main outcomes of this model is that , in equilibrium , selection does not , in general , lead to a homogeneous population formed by a single kind of molecular individual : a particular sequence is no longer _ the outcome _ of selection . a _ set _ of genetically distinct sequences , forming a mutant distribution centered around the master sequence , is produced instead . the mutation rate in this model is the parameter that controls the width of this distribution , that is , how much the quasispecies spreads over the space of sequences . moreover , one immediate consequence of the existence of a maximum eigenvalue is the appearance of a threshold relation . then , for the binary version of this model , as the error rate @xmath58 increases , two distinct regimes are observed in the population composition : the _ quasispecies _ regime , characterized by the master string and its close neighbours , and the _ uniform _ regime , where the @xmath59 possible sequences appear in the same proportion . the transition between these regimes takes place at the _ error threshold _ @xmath60 , whose value depends on the parameters @xmath2 and @xmath20 @xcite . this becomes a genuine phase transition from an adaptive to a disordered neutral phase in the limit @xmath61 @xcite . hence , to proceed further we must specify the replication rate of each sequence , or , in a more concise form , the _ fitness _ or _ replication landscape _ ( this term was originally coined by s. wright @xcite ) , a line drawn by all @xmath20 points related to the sequence space . in particular , the quasispecies concept and the error threshold phenomenon are illustrated more neatly by the so - called _ single - sharp - peak _ landscape . this simple , and probably the most studied of the landscapes , can be constructed by ascribing the replication rate @xmath62 to the master sequence @xmath63 . the remaining sequences , differing by as little as a single mutated monomer , are at a disadvantage @xmath64 as expressed by their replication rate @xmath65 . in figure [ fidom2 ] we present the steady - state molecular frequencies in the case where @xmath66 and @xmath67 , as a function of their hamming distances @xmath68 from the master sequence . that is , the @xmath59 possible sequences were grouped into @xmath69 different classes of sequences , characterized solely by the number of mutant monomers ( @xmath70 ) they have , regardless of the particular positions they occupy inside the sequences . then , if we take as a reference the case @xmath31 , where only the master sequence survives in the selection equilibrium , the parts ( a ) to ( c ) of the figure show three situations in the quasispecies ( or adaptive ) regime , @xmath71 : in ( a ) the master sequence is the more frequent , in ( b ) the master sequence is no longer the more frequent , and in ( c ) , near the error threshold , the number of master copies becomes strongly reduced , but the quasispecies is evolutionarily most versatile because it produces a wide variety of mutants without destabilizing the master sequence . part ( d ) illustrates the uniform ( or stochastic ) regime , @xmath72 , where the @xmath59 possible genomes appear in the same proportion or the @xmath69 classes are distributed by the binomial distribution @xmath73 . therefore , in this simple example of fitness landscape , without errors ( @xmath74 ) or with too much errors ( @xmath72 ) , there is no evolution . in the first case there are no mutants ; in the second case there is no adaptation . moreover , it is possible to show that the existence of a threshold relation , as pointed out above , correlates the mutation rate with a maximum length of the sequences that can be reproducibly maintained by selection ( see @xcite for a simplified case , but with a very intuitive appeal ) . for the single - sharp - peak landscape : @xmath75 that is , once the fidelity degree @xmath76 of the copying mechanism is fixed , the molecule size can not exceed a given value @xmath77 . on the other hand , it is impossible to increase the fidelity of the copying mechanism without changing @xmath2 ; this is the so - called eigen s paradox . it poses a serious difficulty in envisioning life as an emergent property of systems of competing self - replicating macromolecules . some final comments regarding the formulation described above are in order . it is valid only in the limit where the total number of molecules @xmath78 goes to infinity . of course , all real populations are _ finite _ , and they will not behave in the deterministic way expected for an infinite population @xcite . as pointed out by higgs @xcite , the steady - state of a finite population is a dynamic one in which the population can continue to evolve , and therefore it is not equivalent to an infinite population model . finally , it should be added that the error threshold itself is not a general phenomenon , and can be absent even for landscapes as simple as the fujiyama one @xcite ( for a lucid discussion on the limits and further developments of this model see ref.@xcite and references therein ) . for all other landscapes , such as the non - stationary one described in the next section , more elaborate approaches are required to clarify the real meaning of the error threshold . as a side remark , and to establish another connection with what follows , the evolution of a finite population in a random fitness landscape has been recently shown to exhibit a punctuated scenario @xcite . in his excellent book `` how nature works '' @xcite per bak argues that : _ complex behaviour in nature reflects the tendency of large systems with many components to evolve into a critical state where minor disturbances may lead to events , called avalanches , of all sizes . this delicate state evolves without interference of any outside agent and so is a critical self - organized state , that appears as a consequence of the dynamical interactions among individual elements of the system_. self - organized criticality is now a widespread concept and many different systems are known to evolve according to this dynamics . particularly , the sandpile model @xcite is the best one to explain what the famous avalanches are and how to measure them . due to lack of space , we are forced to go directly to the bak - sneppen model and to the avalanches that appear in the large - scale evolutionary process that can explain , for example , the mass explosion of the cambrian period and the mass extinction of the cretaceous , when the dinosaurs disappeared . in this model there are @xmath79 species , each one occupying one site of an unidimensional lattice ( a ring ) . each species has a random fitness @xmath80 . the simulation evolves according to the following rule : * search for the smallest @xmath81 corresponding to species @xmath10 ; * change @xmath81 , @xmath82 and @xmath83 for 3 other values randomly chosen ( mutation or extinction ) ; * return . at the start of the simulation the fitness on average grows , although there are fluctuations up and down . however , after a transient period , the system reaches a stationary critical state where the fitness does not grow any further on average : _ all species have fitness above some threshold _ very close to @xmath84 ( state of `` stasis '' ) . consider a point in time when all species are over the threshold ; at the next step the least fit species ( right at the threshold ) will be selected , eventually starting an avalanche or `` punctuation '' of mutation events . ( in fact , whenever the fitness of a given species changes , it is possible to think that the species has undergone a mutation or that it has become extinct . ) after a while , the avalanche stops , when again all species have fitness above the threshold . the avalanche size corresponds to the number of steps needed to recover the state of stasis ( or equivalently , to the number of active species between two consecutive states of stasis ) . when this process is repeated for large systems ( large number of species ) , one obtains the number @xmath85 of avalanches of size @xmath86 given by the power law : @xmath87 this distribution means that there is no characteristic size for the avalanches , as would happen if instead of a power law it had an exponential behaviour . the larger the system , the larger the possible maximum size of an avalanche is . small avalanches , in which a few number of species become active , are much more frequent than large ones ; however , the probability that a system - sized avalanche occurs , activating all species , is not zero . such a dynamical behaviour can explain the extinction of the dinosaurs without using any external agent , such as meteorites colliding with earth ( but of course does not exclude such a possibility ) . the important point here is the fact that a given species , though highly fit , can be chosen to mutate because one of its neighbours has a low level of fitness . in this sense the species live in a continuously evolving fitness landscape , differently from the quasispecies of the eigen model in which the fitness landscape is fixed : once a replication rate is attributed to a given macromolecule , it never changes . finally , in the next section we introduce the penna model for biological ageing . it is also a model for microevolution , where individual interactions are introduced through a competition for food and space as in the eigen model , but one that presents an age - structure , without reproduction at early ages . the most successful computational model for age - structured populations is by far the penna model @xcite . one of the reasons for its success relies on a particularly well - suited computational representation of a genome by means of a sequence of bits , the bit - string . when grouped into computer words these strings can be efficiently operated on by very fast logical and bit - wise cpu instructions . conceptually , the model is extremely simple , but the results it shows are far from trivial . it has also proved to be flexible enough to be of value in a number of different problems in population dynamics , and the recent literature is eloquent proof of this statement . the biological support for the penna model comes from the mutation accumulation theory of senescence @xcite . in essence , this theory relates the evolution of senescence to the action of age - specific deleterious mutant alleles and the maintenance of some of these genes by the combined effects of mutation and selection pressures . in response to this conflict , deleterious mutant alleles with late ages of action would have higher equilibrium frequencies of affected individuals than genes with similar effects on survival early in reproductive life @xcite . a sufficiently large number of loci capable of mutating to deleterious alleles with age - specific effects would therefore generate a net decline in survival with advancing adult age . we will begin the description of the penna model with its simplest implementation , the one that addresses haploid asexual populations . for a much more detailed explanation , together with a sample computer code , the reader is directed to ref . . the basic structure of the model is the age - structured genome pool . each genome from this pool is associated to an individual , and its pattern of alleles summarizes the genetic heritage acquired by this particular individual . the only genes represented are those with age - specific effects . each gene appears in a particular position ( locus ) of the bit - string , and this position is associated with the age from which it becomes effective . a gene can appear in two alleles , for the @xmath88 possible values of the bit at one locus : a bit set to @xmath89 represents the deleterious allele , and it is set to @xmath90 for the non - deleterious variety . this basic and simple structure allows the computation of the number @xmath91 of active deleterious mutations at any point of an individual life time : one has only to add up the bits of the bit - string from the first locus to the one corresponding to the actual age of that individual . the size @xmath86 of the bit - strings is the first parameter of the model , and determines the maximum theoretical age of the individuals . in this context , age is not to be understood as measured in human years , but rather in a species - specific time unit . selection pressure is modeled by the introduction of a threshold @xmath0 for the number of deleterious mutations that can be simultaneously active in a living individual s genome . usually , the probability of death because of genetic causes is assumed to be given by a step function @xmath92 , with @xmath93 if @xmath94 , which introduces a high degree of non linearity in the model . smoother functional forms have also been used @xcite , but the fundamental results of the penna model do not appear to be sensitive to this choice . death for non - genetic causes , representing the outcome of intra - species competition for the limited resources of the environment , is modeled by a density- and time - dependent quantity , the verhulst factor . this is a mean - field death probability , given by @xmath95 , where @xmath96 is the total population at the beginning of time step @xmath97 and @xmath98 is another parameter of the model that quantifies the above mentioned environmental constraints on the size of the population . the introduction of the verhulst factor , or some equivalent form of limiting factor for the total population , is a necessity in simulational models to avoid population overflow , although its biological motivation and implementation strategy have recently raised some interesting questions @xcite . in an asexual population all the individuals are female . after reaching some minimum age @xmath99 , and until she is @xmath100 time periods old , every female in the population gives birth to @xmath101 offspring at every time step . at this moment , the genetic heritage of the mother is copied to her offspring , and mutations can occur . this process is simulated by generating , for each of the @xmath101 offspring , a genome cloned from that of the mother . on this bit - string , @xmath1 mutations are introduced in randomly chosen loci . it is usual to consider only deleterious mutations , since they are the overwhelming majority in nature . a clever coding trick is in order at this point : for the @xmath102 function implementation of the rule for genetic deaths , one might as well compute at this moment the programmed age of death , by adding up the value of the bits from locus @xmath90 until this sum reaches the threshold @xmath0 ; the last locus to be computed in this sum corresponds to the age at which this individual will die , if not sooner because of the verhulst dagger . this trick avoids having to compute , at each time step , the number of active deleterious mutations for each individual , a time - consuming and redundant operation . with the elements above , a typical simulation of the penna model undergoes the following steps , described in a simple auto - explanatory meta - language : * an initial population of @xmath103 individuals is generated . the usual choices are either a mutation - free population , in which all the bits of all the bit - strings are @xmath90 , or one in which each individual has a random number of mutations , between @xmath90 and @xmath86 , in randomly chosen loci . * for each time step : * compute the verhulst factor @xmath104 ; * for each individual : + increment age by @xmath89 ; + if age is smaller than the programmed age of death and a randomly tossed number in the interval @xmath105 is larger than @xmath104 then reproduce , giving birth to @xmath101 mutated clones ; + else she dies : her genome is erased from the genome pool . these dynamic rules are executed for @xmath106 time steps . in the last @xmath107 averages are taken over the population , and constitute the outcome of the simulation . the quantities usually computed are : * the age distribution of the population , i.e. , a histogram of the number of individuals at each age , with some normalization . * the survival probability as a function of age , defined as the ratio @xmath108 between the population with age @xmath109 at time step @xmath110 and the population that at the previous time step had age @xmath111 . * the mortality rate , defined as the logarithmic measure of the population decay , normalized so that its value at age 1 is zero and where only deaths due to genetic causes are considered . * the genetic state of the population , which can be measured for instance by the fraction of defective genes in the population at each locus . among the many results obtained with the penna model already published , we chose two of the most spectacular to comment on . the first one shows the agreement of the simulation results for the mortality rate with the empirically derived gompertz law @xcite . this law was proposed in the late @xmath112th century to account for the observed mortality rate of the german population , and has since then been verified by a number of observations of both human and mayfly populations . it states that the increase of mortality with age is exponential . the penna model was the first computational model for ageing that could reproduce this result . in figure [ figomp ] we show data derived from a simulation - the particular parameters used can be found in the caption . the second result deals with the catastrophic senescence observed in semelparous species . these are species that reproduce only once in a lifetime , such as the pacific salmon . ageing in these species is called catastrophic because the females die soon after giving birth for the first and only time . to simulate a semelparous population with the penna model one only needs to set @xmath113 , as opposed to having @xmath114 , which is the normal ( iteroparous ) case . these simulations could show that the catastrophic senescence effect is due to the lack of selection value of age - specific genes that become effective after the reproduction age @xcite . with the absence of selection , the mutation pressure turns on deleterious alleles for all these genes . in the computational representation provided by the penna model , all loci associated with ages greater than the reproduction age become set to @xmath89 and the individual dies because of the accumulation of deleterious mutations in the first time step following its progeny . the consequences of this pattern of fixation of deleterious alleles can be clearly seen in the plot for the survival rate shown in figure [ fisalmon ] which compares semelparous and iteroparous populations with equal parameters . the survival rate for the semelparous population has an abrupt decay to zero at age @xmath115 , in sharp contrast with the iteroparous one . setting @xmath113 also greatly simplifies the analytical formulation of the penna model and allowed a formal derivation of the catastrophic senescence effect @xcite . the analysis of figure [ fisalmon ] -b suggests an interesting puzzle . the maximum age of an individual in this population is its last age of reproduction : _ there is no post - reproductive life_!. the conflict between selection and mutations has a very simple outcome , and the individuals die as soon as they loose their function of perpetuating the species . this is not what is seen in nature , however . in human and some other mammal populations , females live after having ended their reproductive period ( after menopause ) . to address this question the penna model needs an extension to sexual diploid populations . these are species where the genetic information is carried by two homologous strains . the effectiveness of a deleterious allele at one locus now depends on a combination of information carried by the two strings . the concept of dominance appears in connection with this issue . if a dominant allele appears in one locus of any of the two strings , it is effective , irrespective of the allele that is present in the homologous locus of the other . for a non - dominant allele to be effective , on the other hand , it must be present in both homologous loci . the appearance of diploid organisms in the life story of our planet marks also the onset of recombination and sex in the process of reproduction @xcite , although there are quite a few examples in nature of asexual reproducing diploid species where recombination is also present . this last strategy of reproduction , asexual but with recombination , is called meiotic parthenogenesis . reproduction in diploid organisms involves the generation of a haploid cell , a process called meiosis , containing a subset of the genetic material of the parent that is to be transmitted to the offspring . to generate this haploid cell , alleles of the two homologous strains are reshuffled and recombined to form a single strain in a process called recombination . diploidity and sex raise a whole new set of questions in population dynamics , some of which have been already studied in the framework of the penna model and will be discussed in the sequel . the extension of the penna model to deal with diploid populations is rather straightforward @xcite . now , the genome of each individual is composed of two bit - strings to be read in parallel : two alleles , one from each string , have to be taken into account to decide if the character of each age - dependent gene is deleterious or not . if this is an homozygote locus , i.e. if both alleles have the same character , then the gene has also this character . if the locus is heterozygote , the decision has to respect the dominance rule . to implement this rule , an extra @xmath86 bits long bit - string is generated at the beginning of a simulation indicating , for each locus , which is the dominant character . in @xmath116 of the @xmath86 loci , randomly chosen from a uniform distribution , the deleterious character is dominant . for these loci , a @xmath89 bit set in any of the two strains suffices to define the character of this gene as deleterious . for the @xmath117 remaining loci , the deleterious allele is recessive , and the homologous bits of the two strings have to be both set to @xmath89 for any of these loci to have a deleterious effect . meiosis in the penna model can be easily tailored to mimic nature . as a side example , apomyctic parthenogenesis , a diploid asexual mode of reproduction without recombination , would be represented by a simple random choice of one of the two genetic strains . for recombination , the usual is to select a random position out of the @xmath86 loci and cut the two strings at this position . two new strings are generated by crossing the resulting four pieces : the left side coming from one of the strings is attached to the right side coming from the other . of the two new strings , one is randomly chosen , and constitutes the genetic material to be inherited by the newborn . for meiotic parthenogenesis , this single strain is cloned : before mutations , the new genome is totally homozygote . for sexual species , a male individual is randomly selected and his genetic material also undergoes meiosis and recombination . the two strains , one coming from the female and another from the male , form the genome of the newborn . its gender is now randomly chosen , with equal probabilities . on each of these two strings , @xmath1 ( deleterious ) mutations are added at randomly chosen loci . in figure [ firegi ] we illustrate the procedures for reproduction of haploid asexual , diploid sexual and diploid meiotic parthenogenetic populations with simple examples . now we are in a position that allows us to address the puzzle with which we ended the last subsection , namely , why do women live as long as men instead of dying immediately after their reproductive period ? and we show in figure [ fisurvsex ] the resulting survival rates when sexual reproduction is added to the model . semelparous populations still suffer catastrophic senescence , even when the males do not loose their reproductive capacity at any age @xcite . but for iteroparous species , females now have a post - reproductive life and there is no difference between male and female survival rates . the presence of males in the population bring some benefits to the females , after all ! but this observation does not ends our quest , for in the same figure we also see that populations for which females do not undergo menopause , and are able to breed for their entire life , have a larger life span . why would then nature `` invent '' menopause ? the answer to this question is now rather elaborate , and has been suggested already in the biological literature . it comes as a result of three new components , and the ability to acomodate and manipulate them is a demonstration of the flexibility of the model . these new components are the need for parental care of the newborn during a certain period of time , the reproductive risk that increases the death probability for a female at the moment of delivery , and the transformation of one of the parameters of the model , the maximum age of reproduction @xmath100 , in an individual and genetically acquired characteristic , now subject to mutations . the first new component is implemented in the model by requiring an infant to have a living mother in order to survive during its first @xmath118 periods of life . for the reproductive risk , a dependence on the number of active deleterious mutations @xmath91 was introduced . thus , a female can die , with a probability essentially given by @xmath119 , at the moment of delivery . if the newborn is a female , she inherits the same @xmath100 of her mother with some probability @xmath120 , or mutates to have it increased ( decreased ) by @xmath89 with probability @xmath121 . the darwinian dynamics of the model is sufficient to produce a self - organization of the distribution of the menopause age of the female population , showing that inhibition of reproduction after a certain age is actually beneficial for the species as a whole @xcite . in figure [ fimeno ] the distribution of the age of menopause onset throughout the population is shown in a comparison between a population where parental care is not needed and one where an infant aged below a minimum would die if the mother was not any more present . the maintenance of sexual reproduction among the great majority of species in nature , in spite of the inherent cost of having to produce males to assure reproduction , is still one of the great puzzles of biology . in fact , a simple reasoning shows that the need of two parents to generate even a single offspring should give asexual varieties a two - fold advantage over sexual ones @xcite . the advantage of sex relies on its ability to create greater genetic diversity , since the pool of alleles from which the newborn genome is extracted is different for each mating pair . asexual reproduction , on the other hand , generates new genomes from a more limited pool , since there is only one parent involved . it is not clear though in what circumstances this greater diversity provided by sex would give it the upper hand against , say , meiotic parthenogenesis . one could argue that the species would benefit from the cloning of well - fitted genome , only possible in asexual reproduction , and that sex would make these genomes short - lived for exactly the same reasons it can create diversity . sex could possibly be more efficient in getting rid of bad mutations , by bundling them together through mating and expelling them from the genetic pool through selection . these are as yet open questions , and the penna model has been used to address them , even when the age structure of the population is not the issue . this is possible because of its particularly simple implementation of a selection mechanism , which is a general requirement for any model to be useful in this context . for the evaluation of diversity in the penna model one measures the number of different alleles , or bits , for each pair of genomes in the population . the resulting distribution of this so - called hamming distance has a gaussian character for any reproduction strategy . the comparison between sex and meiotic parthenogenesis show a similar width for the distributions , but a higher value for the distance where it peaks in the sexual case @xcite . a particularly interesting reflex of this greater diversity can be seen when a genetic catastrophe is provoked at a chosen time step by instantaneously setting an extra deleterious mutation at a chosen locus in all the individuals . an equivalent , and perhaps more easily translated into biological terms , procedure would be to decrease the threshold of deleterious mutations @xmath0 by one , representing a sudden depletion of vital environmental life protection resources . thanks to their greater diversity , sexual populations are always resistant to this catastrophe , whereas simple asexual reproduction leads invariably to extinction , as shown in figure [ ficat ] . for meiotic parthenogenesis , the outcome is not so clearly cut , but extinction is a possibility @xcite . a number of theories have been put forth to try to explain the evolution and maintenance of sexual reproduction . in the center of this debate is the so - called `` red queen '' hypothesis , that relies heavily on the ideas of diversity discussed above . in essence , it holds the action of genetically matching parasites as responsible for creating a rapidly changing environment . in this unstable ecology , only varieties that can mutate their genomic pool at least as fast as the adaptation of the parasites proceed can survive . the theory derives its name from this endless race , quoting from the red queen of lewis carol s alice in wonderland : `` it takes all the running you can do , to keep in the same place . '' in fact , recent observations of competing varieties of a freshwater snail , _ potamopyrgus antipodarum _ , have shown that there is a strong correlation between the prevalence of one reproduction regime and the concentration in its habitat of the trematode _ microphallus _ , a parasite that renders the snail sterile by eating its gonads @xcite . namely , the asexual variety is predominant where the parasite appears in small concentrations , whereas higher concentrations of the trematode forces the species to prefer a sexual regime . this correlation could be shown to exist in simulations of a conveniently modified penna model . the parasites are represented by a dynamically changing memory bank of genomes of some fixed number of entries . each entry is modified if it comes into contact with the same genome twice in a row ; in this case , it memorizes this pattern and stores it in the memory bank . at each time step , before the reproduction cycle , each female of the population is probed by a fixed number @xmath122 of randomly chosen entries of the parasite bank . if one of these entries is a perfect match for the female s genome , she is rended sterile and can no longer reproduce . the number of parasite exposures @xmath122 is an indirect measure of the parasite concentration in the habitat . for the host population , the reproductive regime of the females is no longer a fixed character , but can mutate with some small probability . the simulations begin in the absence of the parasite infestation , and the initial population is set to have a sexual reproductive regime . as soon as the meiotic population appears , due to mutations in the reproductive regime , it overrides the sexual variety , in a demonstration of the two - fold disadvantage of sex above mentioned , and sex barely subsists due to infrequent back - mutations from the asexual variety . at some time step , the parasite infestation is turned on . the resulting predominant variety is going to depend solely on the intensity of this infestation , as measured by the exposure parameter @xmath122 . for small values of @xmath122 , the asexual variety has the upper hand . as @xmath122 is increased , a first - order transition is seen to a configuration dominated by the sexual population @xcite . figure [ firedq ] shows the fraction of females in the population that reproduces sexually , as a function of the exposure parameter @xmath122 . the sudden jump in this fraction signals the order of the transition . it is not difficult to find in the animal kingdom species that live and work in sexual pairs , but sometimes have an extra - pair relation , like the scandinavian great reed warbler , chimpanzees , etc ... ( of course some disgusting men also belong to this category ) . as already shown by martins and penna @xcite , such a behaviour increases the genetic diversity and may lead to better fitted offspring depending on how females select the males for an extra - pair relation . however , as in the case of the parasites presented before , nature not always chooses the strategy leading to the highest reproduction rate . another example is the california mouse @xcite , one of the rare monogamous species that have been found . these mouses live in a extremely cold place , and in order to survive the pups must be continuously heated by the body of one of the parents . when the male abandons the nest , the female very often kills the babies . starting with a population with half of the males faithful and the other half non - faithful , sousa and moss de oliveira @xcite have shown that depending on the death probability of the abandoned offspring , the population may self - organize in a situation where all males are faithful despite of reproducing lesser . in their simulations , monogamy is paternally transmitted and exclusively related to parental care . in fact it is already known that there some genes responsible for maternal care that are paternally transmitted @xcite . another interesting result obtained with the penna model concerns the higher mortality of males when compared to the females one . the mortality curve as a function of age for females is lower since birth until advancing ages ( around 90 years ) , when both males and females mortalities become equal . stauffer et al @xcite introduced somatic mutations ( that are not transmitted to the offspring ) into the model , atributting to males a higher somatic mutation rate than to females . with this strategy they were able to reproduce the observed behaviour of the mortalities , with the females one lower than that of males until advancing ages , when the genetic mutations dominate and the two curves collapse . penna and wolf @xcite obtained the same result atributting to the females a higher value of the limit number of genetic diseases @xmath0 than to the males . however , the best strategy was proposed by cebrat @xcite , and confirmed by schneider @xcite et al . , that modified the model in order to distinguish the double x chromosomes of the females from the single one of males . considering the mutations in the single x male chromosome as dominant mutations , even more realistic results were obtained . finally , we must say that it has also been possible to predict some unknown effects using this model . for instance , it has been shown that in small populations , if a given percentage of males is periodically substituted by the same percentage of males coming from a large population , the extinction of small populations due to inbreeding may be avoided @xcite . also a nice strategy for fishing some species in which fertility varies with size in order to warrant a larger stock without loosing money , has been recently proposed by racco and penna @xcite . we have shown that different evolutionary models found in the literature are connected to the biological ageing ones through the darwin s theory of selection of the fittest . the models we have presented here are the most simple ones , but their results are far from trivial . the eigen model for microevolution makes clear the difference between segregation and selection , as well as the connection between mutations and diversity . the bak - sneppen model exemplifies the importance of a continuously evolving fitness landscape to simulate large - scale or macroevolution . finally we have presented the penna model for biological ageing and some of its most important results . ageing is an unavoidable process ( except for some _ rare individuals _ like d. stauffer , who is eternally young ) and has been extensively studied by many different scientists , since a very long time . although the evolutionary theories for senescence have appeared around 1950 , monte carlo simulations on this subject started only after the publication of the partridge - barton analytical mathematical model in 1993 . the penna model is now the most widespread monte carlo technique to simulate and study the different aspects of population dynamics , including ageing . in this review we have focused attention on results concerning the differences between reproductive regimes and the advantages of sexual reproduction ( although our arguments have not proved good enough to convince the rare individual just mentioned above that males are all alike but still useful ) . s.m.o . and j.s.s.m . thank p.m.c . de oliveira , d. stauffer , t.j.p . penna , a.t . bernardes , a.o . sousa and s. cebrat for many discussions and collaborations in previous papers . s.m.o.s work is partially supported by the brazilian agencies cnpq , faperj and capes . d.a.s work is supported by fapesp . j.s.s.m.s work is supported by doe grant de - 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( 1996 ) 61 . y - c . zhang , phys . e 55 ( 1997 ) r3817 . medawar , an unsolved problem in biology , h.k . lewis , london , 1952 . e.b . edney and r.w . gill , nature 220 ( 1968 ) 281 . b. charlesworth , evolution in age - structured populations , 2nd edition , cambridge university press , 1994 . s. moss de oliveira , p.m.c . de oliveira and d. stauffer , evolution , money , war and computers , teubner , 1999 . d. stauffer , int . c 10 ( 1999 ) 1363 . s martins and s. cebrat , e - print cond - mat/0002466 , to appear in theory in biosciences ( 2000 ) . mueller and m.r . rose , exp . 30 ( 1995 ) 553 . penna , s. moss de oliveira and d. stauffer , phys . e 52 ( 1995 ) r3309 . penna and s. moss de oliveira , j. physique i 5 ( 1995 ) 1697 . j. maynard smith , the evolution of sex , cambridge university press , 1978 . . bernardes , ann . physik 5 ( 1996 ) 539 . d. stauffer , p.m.c . de oliveira , s.m . moss de oliveira and r.m . zorzenon dos santos , physica a 231 ( 1996 ) 504 . k.m . fehsenfeld , j.s . s martins , s. moss de oliveira and a.t . bernardes , int . j. mod c 9 ( 1998 ) 935 . s. moss de oliveira , a.t . bernardes and j.s . s martins , eur . j. b 7 ( 1999 ) 501 . s martins and s. moss de oliveira , int . c 9 ( 1998 ) 421 . c.m . lively , e.j . lyons , a.d . peters , and j. jokela , evolution 52 ( 1998 ) 1482 . dybdahl and c.m . lively , evolution 52 ( 1998 ) 1057 . howard and c.m . lively , nature ( london ) 367 ( 1994 ) 554 . s martins , phys . e 61 ( 2000 ) r2212 . martins and t.j.p . penna , int . phys . c9 ( 1998 ) 491 . v. morell , science 281 ( 1998 ) 1983 . sousa and s. moss de oliveira , eur . j. b10 ( 1999 ) 781 . l. lefebvre , s. viville , s.c . barton , f. ishino , e.b . keverne and m.a . surani , nature genetics 20 ( 1998 ) 163 . r.s . bridges , nature genetics 20 ( 1998 ) 108 . s. moss de oliveira , p.m.c . de oliveira and d. stauffer , braz . j. phys . 26 ( 1996 ) 626 . penna and d. wolf , theory biosc . 116 ( 1997 ) 118 . s. cebrat , physica a258 ( 1998 ) 493 . j. schneider , s. cebrat and d. stauffer , int . phys . c9 ( 1998 ) 721 . sousa and s. moss de oliveira , physica a278 ( 2000 ) 563 . a. racco , master thesis , physics institute of universidade federal fluminense , 1999 .

the idea of this review is to connect the different models of evolution to those of biological ageing through darwin s theory . we start with the eigen model of quasispecies for microevolution , then introduce the bak - sneppen model for macroevolution and , finally , present the penna model for biological ageing and some of its most important results . we also explore the concept of coevolution using this model .

many endocrine responses in tortoises are very similar to those of other reptiles , even if they also show some specific aspects . several reptiles , including sea turtles and tortoises , are known to modify their stress response according to their body condition and analysis of blood constituents is useful in the diagnosis of health and disease status [ 2 , 3 ] and has helped to identify stressed or ill tortoises [ 46 ] . previous studies have described the effects of external and internal factors on the capacity of individuals to induce different physiological coping strategies in response to stressors . changes of animal homeostasis induce a hormonal response that results in an increase of glucocorticoids , catecholamines , and other blood factors [ 79 ] , necessary to restore their homeostasis . factors , such as disease and body condition , have been associated with significant changes in plasma corticosterone [ 1013 ] . measurement of plasma cortisol values is commonly used as a diagnostic technique to assess welfare or stress conditions of individual animals [ 14 , 15 ] . however , there appears to be fragmentary information on reference intervals and physiological alterations in hormonal values in tortoises [ 16 , 17 ] and in free - ranging desert tortoises . in the last years the clinic reports , as repair and dressing of fractures , surgeries , shell diseases , and mycoplasmosis , related to cases suffered by chelonia , were scarce and inadequate [ 19 , 20 ] . moreover , recently terrestrial tortoises and aquatic turtles are considered company animals and are often kept as pets ; their numbers are increased , and the requests of routine veterinary checks are arisen [ 21 , 22 ] . in addition , there are many occasions when it is necessary to transport the tortoises . this could be to transfer to a new home , even holiday boarding or a visit for routine veterinary checks . tortoises , as all animals , can suffer from stress induced by a new environment much more quickly if their journey is planned with a little thought from their owner . on this basis , the objective of the present study was to evaluate the effects of handling and transport stress on reference values of circulating cortisol concentrations in tortoises . comparison between basal and posthandling and transport values could offer the opportunity to further our knowledge and improve the understanding of the adrenocortical response to stress and the healthy status of tortoises . the study was carried out on a total of twenty - three not hibernated tortoises ( testudo hermanni ) , in good health ( 9 males and 14 females ) , aged 820 years ( 10 aged 812 y and 13 aged 1320 y ) , weighting 709 144.97 g , the straight carapace length ranging from 13.50 to 18.50 cm ( 15.50 1.41 ) . on the basis of straight carapace length ( scl ) the subjects were classified as juvenile tortoise ( < 40 cm ) . we examined circulating cortisol concentrations four weeks prior to and four weeks following handling and transport in experimental group ( 10 tortoises , 4 males and 6 females ) , and only following to handling in control group ( 13 tortoises , 5 males and 8 females ) . the body mass of the tortoises was measured to the nearest 10 g with 2 kg spring balance . the subjects were kept at the private home with natural light ; they were fed with green vegetables , cooked potatoes and had free access to clean drinking water ad libitum . a plastic and opaque container just slightly bigger than the tortoises was used and secured in the boot of car , ensuring it into van so that it can not move around or shoot across the other side of the boot . each animal was given a thorough physical examination ( examination of the oral and anal orifice , heart rate , respiratory rate , hydration state , body weight , and straight carapace length ) , and individuals did not shown signs of clinical illness ( e.g. , weight loss , hyperthermia , anorexia , and macroparasites ) . blood samples were collected by sterile syringe from the caudal venous sinus for each turtle with a 0.6 gauge ( 23 g ) needle , in basal condition ( four weeks prior to handling and transport ) and four weeks following to handling and short road transport of 40 km ( duration of 90 minutes ) . the long interval between basal and posthandling and transport sampling ( four weeks ) was imposed by the tortoises ' size and body weight . at their arrival at veterinary clinic ( messina , italy ) the subjects were submitted to clinic examination for evaluation of the general health status and then the subjects were submitted to blood sampling . blood samples were collected in both groups in spring ( may / june ) at 10.30 a.m. into lithium heparin tube ( venoject , terumo , belgium ) and plasma was harvested and stored in eppendorf tubes at 20c until assayed for cortisol values . plasma total cortisol concentrations were analysed in duplicate through a competitive enzyme assay ( eia , radim , pomezia , roma , italy ) . during the first incubation , sample cortisol competed with the cortisol conjugated to horseradish peroxidase ( hrpo ) for binding to the specific sites of the antiserum coated on the wells . following incubation , the enzyme activity , which was bound to the solid phase , was inversely proportional to the cortisol concentration in calibrators and samples , which was evidenced by incubating the wells with a chromogen solution ( tetramethylbenzidine , tmb ) in a substrate buffer . colourimetric reading was carried out using a spectrophotometer at 450 and 405 nm ( sirio s , radim / seac co. , rome , florence , italy ) . the assay sensitivity was 5 ng / ml . the intra- and interassay coefficients of variation ( cvs ) were 4.6% and 6.9% , respectively . significant differences between basal and posthandling and transport values were established using the student 's t - test for paired data . significant differences between different genders , age , and groups ( experimentals and controls ) were established using the student 's t - test for unpaired data . all calculations were performed using the prism package ( graphpad software inc . , san diego , ca ) . basal cortisol concentrations , ranged between 9.79 and 16.52 nmol / l , and posthandling and transport concentrations , ranged between 31.12 and 59.84 nmol / l , were partially in agreement with physiological ranges previously reported in the literature in stressed and unstressed juvenile turtles . compared to basal condition , circulating cortisol concentrations was higher after transport ( + 244% ; p < 0.001 ) in total subjects , with an increase of + 246% ( p < 0.001 ) in males , + 236% ( p < 0.005 ) in females , + 370% ( p < 0.005 ) in subjects aged 812 years , and + 240% ( p < 0.001 ) in those aged 1320 years , respectively . no significant differences between cortisol basal concentrations of experimental group and control group were observed . on the basis of different gender and age ( figure 1 ) , no significant differences in basal cortisol concentrations between males and females and between tortoises aged 812 years and those aged 1320 years were observed . in addition , subjects aged 812 years showed no significant lower basal cortisol concentrations and no significant higher posttransport concentrations than tortoises aged 1320 years . comparison between our data and other results are somewhat limited due to potential differences between tortoise populations as well as to variations in analytical methods . researches are mainly focused on wild populations of the west african hinge - backed tortoise ( kinixys erosa ) , the free - ranging desert tortoise in the mojave desert and in marginated tortoise ( testudo marginata ) in different geographic environments [ 18 , 22 , 24 ] and in mojave population of the desert tortoises ( gopherus agassizii ) . in addition , many researches reported corticosterone ranges because it is the major glucocorticoid in reptiles secreted from adrenocortical tissue [ 6 , 8 , 2527 ] and the syndromes of glucocorticoid resistance were observed . cortisol and corticosterone are the main glucocorticoid hormones usually presented and discussed in the literature in terms of the mean responses to stress stimuli in most animals including reptiles , and they have been used as indicators to determine the duration and severity of stress [ 2931 ] . whilst the physiological functions of corticosterone have been more investigated in domestic and wild animals there are relatively insufficient descriptions of changes in serum cortisol concentrations in reptiles in general and tortoises in particular . however , there are neither studies on changes in cortisol concentration relative to transport stress in tortoises nor data on how long this adrenocortical response could persist . because handling tortoises to collect blood can induce stress that could influence their ability to detect a response to transport , we conducted this study to quantify the time required for testudo hermanni to elicit elevated total cortisol concentrations after short road transport . hence , the comparisons of results obtained in this study with previously published data for tortoises revealed some discrepancies for circulating cortisol concentrations . however , some differences may also possibly be explained by influence of individual variability ( gender , age , and size ) , physiologic and breeding status [ 22 , 24 ] , or geographical location , habitat , seasonal variations [ 19 , 32 , 33 ] , and immunological system . the differences in cortisol values , as reported for corticosterone , could be indirectly due to intrinsic biological rhythms or could be directly determined by handling in tortoises [ 10 , 12 , 35 , 36 ] . in addition , data obtained in healthy tortoises , without significant differences in basal condition between male and female cortisol values , confirm previous data described for corticosterone in gopherus polyphemus . in addition , previous studies [ 3840 ] confirm higher basal cortisol concentrations in males than females . data obtained confirm that males showed the earlier adrenocortical response to handling and transport stress compared to females . nevertheless , the significant differences between before and after cortisol concentrations reported in our study suggest that this hormone , namely the corticosterone , remains already significantly higher after 30 and 60 minutes after handling and release from restraint . in addition , cash et al . noted that there was no change in glucocorticoids in wild red - eared slider turtles ( trachemys scripta elegans ) in the first 10 minutes of capture , but concentrations significantly increased within 30 minutes . this lag in glucocorticoid response is consistent with previous research carry out on wild gopher tortoises ( gopherus polyphemus ) [ 37 , 40 ] and free - living loggerhead turtles ( caretta caretta ) . plasma corticosterone did not increase significantly in acth - injected desert tortoises until 20 minutes postinjection , but there was significant increase 60 minutes postinjection , with an average increase of 392% ( + / 129% ) . stress is generally assumed to be an inevitable outcome of transport because it requires the handling and movement of animals . though , data obtained confirm that handling , confinement , and transport can affect metabolism and physical activity of tortoises [ 39 , 41 ] , resulting in the highest cortisol concentrations . since the tortoises were submitted to blood sampling both four weeks prior to ( in basal conditions ) and four weeks following handling and transport , this aversive stimuli could be considered neutral . this hypothesis was confirmed by the absence of significant differences between control and basal cortisol values . on the contrary , handling , confinement , and transport can be considered stressful , as confirmed by significant higher cortisol concentrations four weeks following experimental protocols than basal values . on the basis of different age , subjects aged 812 years showed lower basal cortisol concentrations but higher posttransport concentrations than tortoises aged 1320 years . these differences , even if not significant , can be interpreted in terms of different stress responses , according to different age , as reported by gregory and schmid . subjects aged 1320 years seemed to be more protected against transport stress . on the basis of different gender , the results obtained in females did not explain the effect of handling and transport on cortisol changes , since the cortisol concentration averages in tortoises were included in subjects ranged 812 years ; in fact , the subjects aged 812 years included the fourteen females . an alternative explanation for the presence of the highest basal cortisol concentrations in males in the present study could be proper the age of these specimens , ranged between 13 and 20 years . the absence of significant differences of cortisol concentrations between males and females confirms previous data observed in free - living turtles for corticosterone secretion in response to capture and handling . the results obtained do not exclude that the highest cortisol concentrations in basal conditions of males and subjects aged 1320 years may have determined the lowest cortisol concentrations after handling and transport because the secretions of this hormone is yet high and near the physiological range reported for tortoises . on the other hand , the highest cortisol values observed in males and in subjects aged 812 years after transport could be explained on the basis of a major secretion or reserve of cortisol concentrations . it is possible that stress conditions were added by handling , confinement , and transport , which were always performed in tortoises only four weeks following to handling and transport . in conclusion , the significant differences observed between , before , and after determinations in healthy tortoises , in accordance with different gender , suggest a similar response to handling and transport stress ; however , the cortisol increase was more representative in males ( + 246% ) than in females ( + 236% ) . on the contrary , the significant increase of cortisol concentrations in tortoises aged 812 years suggest that the younger subjects response with a significant secretion of this hormone because probably handling and transport may be mainly perceived as stressful . it appears that these results comprise a variety of stressors , as handling ( including weighing and measuring , routine veterinary check ) , restraint , confinement , transport , while blood sampling may have elicited the stress response . our data suggest that blood sampling per se is not an acutely stressful event in juvenile tortoises ; hence , it possible that tortoises could exhibit a diminished responsiveness of central and peripheral catecholaminergic systems to acute stress , simultaneously with progressive hypothalamic corticotrophin - releasing hormone deficiency , as reported in nonsenescent older rats and horses [ 43 , 44 ] . in the present study we tested the hypothesis that tortoises submitted to handling and transport stress possess a hyperresponsive hypothalamo - pituitary - adrenal ( hpa ) axis in relation to turtles . in fact previous studies showed that the adrenocortical response of sea turtles appears to be substantially slower than that of other vertebrates [ 4547 ] . the veterinary check could be a concomitant cause of additional stress because every subject was submitted to the same handling by the same operator . because the rate of increase in circulating hormone concentrations during handling is considered a marker of the sensitivity of the hpa axis also in lizards and turtles and can be used to evaluate an animal 's endocrine sensitivity to stress [ 8 , 23 , 26 , 27 ] , monitoring tortoise blood cortisol changes can be a way to evaluate the physiologic and health status of this populations ( testudo hermanni ) . in addition , this hormone may be a useful indicator of the environmental status , because these species are very sensitive to habitat changes . the appropriate sample handling in order to deliver meaningful diagnostic data and the establishment of baseline blood cortisol profiles for healthy tortoises are a priority to provide accurate and reproducible quantitative analyses in this species . despite the lack of the number of subjects , this study extends our knowledge of the effects of handling and transport of tortoises and raises interesting questions about the adrenocortical response of these stressful stimuli in this species . previous work on corticosterone responses to capture and restraint in turtles and tortoises showed different blood sampling time , ranging between 30 minutes and 24 hours . in conclusion , although circulating cortisol or corticosterone concentrations are the golden standard to study the hypothalamic - pituitary - adrenal ( hpa ) axis , many complementary investigation tools have been developed to overcome the various problems related to blood sampling time .

the goal of this study was to analyze circulating cortisol levels from tortoises ( testudo hermanni ) to establish reference intervals and to develop guidelines for the interpretation of the effect of handling and transport stress . blood samples were obtained from the caudal venous from 23 healthy juvenile tortoises ( 9 males and 14 females ) , aged 820 years , in basal condition , four weeks prior to and four weeks following handling and short transportation . the study was carried out on the experimental group : 10 tortoises , 4 males and 6 females , and on a control group : 13 tortoises , 5 males and 8 females . compared to basal values , circulating cortisol concentrations was higher after handling and transport ( + 286% ; p < 0.001 ) , with an increase of + 246% ( p < 0.001 ) in males , + 236% ( p < 0.005 ) in females , + 370% ( p < 0.005 ) in subjects aged 812 years , and + 240% ( p < 0.001 ) in subjects aged 1320 years . these observations support the hypotheses that cortisol may act to mediate the effects of handling and transport stress in this species and that four weeks following handling and transport were insufficient to restore their homeostasis .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Collections of Information Antipiracy Act''. SEC. 2. MISAPPROPRIATION OF COLLECTIONS OF INFORMATION. Title 17, United States Code, is amended by adding at the end the following new chapter: ``CHAPTER 12--MISAPPROPRIATION OF COLLECTIONS OF INFORMATION ``Sec. ``1201. Definitions. ``1202. Prohibition against misappropriation. ``1203. Permitted acts. ``1204. Exclusions. ``1205. Relationship to other laws. ``1206. Civil remedies. ``1207. Criminal offenses and penalties. ``1208. Limitations on actions. ``Sec. 1201. Definitions ``As used in this chapter: ``(1) Collection of information.--The term `collection of information' means information that has been collected and has been organized for the purpose of bringing discrete items of information together in one place or through one source so that users may access them. ``(2) Information.--The term `information' means facts, data, works of authorship, or any other intangible material capable of being collected and organized in a systematic way. ``(3) Potential market.--The term `potential market' means any market that a person claiming protection under section 1202 has current and demonstrable plans to exploit or that is commonly exploited by persons offering similar products or services incorporating collections of information. ``(4) Commerce.--The term `commerce' means all commerce which may be lawfully regulated by the Congress. ``(5) Product or service.--A product or service incorporating a collection of information does not include a product or service incorporating a collection of information gathered, organized, or maintained to address, route, forward, transmit, or store digital online communications or provide or receive access to connections for digital online communications. ``Sec. 1202. Prohibition against misappropriation ``Any person who extracts, or uses in commerce, all or a substantial part, measured either quantitatively or qualitatively, of a collection of information gathered, organized, or maintained by another person through the investment of substantial monetary or other resources, so as to cause harm to the actual or potential market of that other person, or a successor in interest of that other person, for a product or service that incorporates that collection of information and is offered or intended to be offered for sale or otherwise in commerce by that other person, or a successor in interest of that person, shall be liable to that person or successor in interest for the remedies set forth in section 1206. ``Sec. 1203. Permitted acts ``(a) Individual Items of Information and Other Insubstantial Parts.--Nothing in this chapter shall prevent the extraction or use of an individual item of information, or other insubstantial part of a collection of information, in itself. An individual item of information, including a work of authorship, shall not itself be considered a substantial part of a collection of information under section 1202. Nothing in this subsection shall permit the repeated or systematic extraction or use of individual items or insubstantial parts of a collection of information so as to circumvent the prohibition contained in section 1202. ``(b) Gathering or Use of Information Obtained Through Other Means.--Nothing in this chapter shall restrict any person from independently gathering information or using information obtained by means other than extracting it from a collection of information gathered, organized, or maintained by another person through the investment of substantial monetary or other resources. ``(c) Use of Information for Verification.--Nothing in this chapter shall restrict any person from extracting information, or from using information within any entity or organization, for the sole purpose of verifying the accuracy of information independently gathered, organized, or maintained by that person. Under no circumstances shall the information so extracted or used be made available to others in a manner that harms the actual or potential market for the collection of information from which it is extracted or used. ``(d) Nonprofit Educational, Scientific, or Research Uses.--Nothing in this chapter shall restrict any person from extracting or using information for nonprofit educational, scientific, or research purposes in a manner that does not harm the actual or potential market for the product or service referred to in section 1202. ``(e) News Reporting.--Nothing in this chapter shall restrict any person from extracting or using information for the sole purpose of news reporting, including news gathering, dissemination, and comment, unless the information so extracted or used is time sensitive, has been gathered by a news reporting entity for distribution to a particular market, and has not yet been distributed to that market, and the extraction or use is part of a consistent pattern engaged in for the purpose of direct competition in that market. ``(f) Transfer of Copy.--Nothing in this chapter shall restrict the owner of a particular lawfully made copy of all or part of a collection of information from selling or otherwise disposing of the possession of that copy. ``Sec. 1204. Exclusions ``(a) Government Collections of Information.-- ``(1) Exclusion.--Protection under this chapter shall not extend to collections of information gathered, organized, or maintained by or for a government entity, whether Federal, State, or local, including any employee or agent of such entity, or any person exclusively licensed by such entity, within the scope of the employment, agency, or license. Nothing in this subsection shall preclude protection under this chapter for information gathered, organized, or maintained by such an agent or licensee that is not within the scope of such agency or license, or by a Federal or State educational institution in the course of engaging in education or scholarship. ``(2) Exception.--The exclusion under paragraph (1) does not apply to any information required to be collected and disseminated-- ``(A) under the Securities Exchange Act of 1934 by a national securities exchange, a registered securities association, or a registered securities information processor, subject to section 1205(g) of this title; or ``(B) under the Commodity Exchange Act by a contract market, subject to section 1205(g) of this title. ``(b) Computer Programs.-- ``(1) Protection not extended.--Subject to paragraph (2), protection under this chapter shall not extend to computer programs, including, but not limited to, any computer program used in the manufacture, production, operation, or maintenance of a collection of information, or any element of a computer program necessary to its operation. ``(2) Incorporated collections of information.--A collection of information that is otherwise subject to protection under this chapter is not disqualified from such protection solely because it is incorporated into a computer program. ``Sec. 1205. Relationship to other laws ``(a) Other Rights Not Affected.--Subject to subsection (b), nothing in this chapter shall affect rights, limitations, or remedies concerning copyright, or any other rights or obligations relating to information, including laws with respect to patent, trademark, design rights, antitrust, trade secrets, privacy, access to public documents, and the law of contract. ``(b) Preemption of State Law.--On or after the effective date of this chapter, all rights that are equivalent to the rights specified in section 1202 with respect to the subject matter of this chapter shall be governed exclusively by Federal law, and no person is entitled to any equivalent right in such subject matter under the common law or statutes of any State. State laws with respect to trademark, design rights, antitrust, trade secrets, privacy, access to public documents, and the law of contract shall not be deemed to provide equivalent rights for purposes of this subsection. ``(c) Relationship to Copyright.--Protection under this chapter is independent of, and does not affect or enlarge the scope, duration, ownership, or subsistence of, any copyright protection or limitation, including, but not limited to, fair use, in any work of authorship that is contained in or consists in whole or part of a collection of information. This chapter does not provide any greater protection to a work of authorship contained in a collection of information, other than a work that is itself a collection of information, than is available to that work under any other chapter of this title. ``(d) Antitrust.--Nothing in this chapter shall limit in any way the constraints on the manner in which products and services may be provided to the public that are imposed by Federal and State antitrust laws, including those regarding single suppliers of products and services. ``(e) Licensing.--Nothing in this chapter shall restrict the rights of parties freely to enter into licenses or any other contracts with respect to the use of collections of information. ``(f) Communications Act of 1934.--Nothing in this chapter shall affect the operation of the provisions of the Communications Act of 1934 (47 U.S.C. 151 et seq.), or shall restrict any person from extracting or using subscriber list information, as such term is defined in section 222(f)(3) of the Communications Act of 1934 (47 U.S.C. 222(f)(3)), for the purpose of publishing telephone directories in any format. ``(g) Securities Exchange Act of 1934 and Commodity Exchange Act.-- Nothing in this chapter shall affect-- ``(1) the operation of the provisions of the Securities Exchange Act of 1934 (15 U.S.C. 58a et seq.) or the Commodity Exchange Act (7 U.S.C. 1 et seq.); ``(2) the public nature of information with respect to quotations for and transactions in securities that is collected, processed, distributed, or published pursuant to the requirements of the Securities Exchange Act of 1934; ``(3) the obligations of national securities exchanges, registered securities associations, or registered information processors under the Securities Exchange Act of 1934; or ``(4) the jurisdiction or authority of the Securities and Exchange Commission or the Commodity Futures Trading Commission. ``Sec. 1206. Civil remedies ``(a) Civil Actions.--Any person who is injured by a violation of section 1202 may bring a civil action for such a violation in an appropriate United States district court without regard to the amount in controversy, except that any action against a State governmental entity may be brought in any court that has jurisdiction over claims against such entity. ``(b) Temporary and Permanent Injunctions.--Any court having jurisdiction of a civil action under this section shall have the power to grant temporary and permanent injunctions, according to the principles of equity and upon such terms as the court may deem reasonable, to prevent a violation of section 1202. Any such injunction may be served anywhere in the United States on the person enjoined, and may be enforced by proceedings in contempt or otherwise by any United States district court having jurisdiction over that person. ``(c) Impoundment.--At any time while an action under this section is pending, the court may order the impounding, on such terms as it deems reasonable, of all copies of contents of a collection of information extracted or used in violation of section 1202, and of all masters, tapes, disks, diskettes, or other articles by means of which such copies may be reproduced. The court may, as part of a final judgment or decree finding a violation of section 1202, order the remedial modification or destruction of all copies of contents of a collection of information extracted or used in violation of section 1202, and of all masters, tapes, disks, diskettes, or other articles by means of which such copies may be reproduced. ``(d) Monetary Relief.--When a violation of section 1202 has been established in any civil action arising under this section, the plaintiff shall be entitled to recover any damages sustained by the plaintiff and defendant's profits not taken into account in computing the damages sustained by the plaintiff. The court shall assess such profits or damages or cause the same to be assessed under its direction. In assessing profits the plaintiff shall be required to prove defendant's gross revenue only; defendant must prove all elements of cost or deduction claims. In assessing damages the court may enter judgment, according to the circumstances of the case, for any sum above the amount found as actual damages, not exceeding three times such amount. The court in its discretion may award reasonable costs and attorney's fees to the prevailing party and shall award such costs and fees where it determines that an action was brought under this chapter in bad faith against a nonprofit educational, scientific, or research institution, library, or archives, or an employee or agent of such an entity, acting within the scope of his or her employment. ``(e) Reduction or Remission of Monetary Relief for Nonprofit Educational, Scientific, or Research Institutions.--The court shall reduce or remit entirely monetary relief under subsection (d) in any case in which a defendant believed and had reasonable grounds for believing that his or her conduct was permissible under this chapter, if the defendant was an employee or agent of a nonprofit educational, scientific, or research institution, library, or archives acting within the scope of his or her employment. ``(f) Actions Against United States Government.--Subsections (b) and (c) shall not apply to any action against the United States Government. ``(g) Relief Against State Entities.--The relief provided under this section shall be available against a State governmental entity to the extent permitted by applicable law. ``Sec. 1207. Criminal offenses and penalties ``(a) Violation.-- ``(1) In general.--Any person who violates section 1202 willfully, and-- ``(A) does so for direct or indirect commercial advantage or financial gain; or ``(B) causes loss or damage aggregating $10,000 or more in any 1-year period to the person who gathered, organized, or maintained the information concerned, shall be punished as provided in subsection (b). ``(2) Inapplicability.--This section shall not apply to an employee or agent of a nonprofit educational, scientific, or research institution, library, or archives acting within the scope of his or her employment. ``(b) Penalties.--An offense under subsection (a) shall be punishable by a fine of not more than $250,000 or imprisonment for not more than 5 years, or both. A second or subsequent offense under subsection (a) shall be punishable by a fine of not more than $500,000 or imprisonment for not more than 10 years, or both. ``Sec. 1208. Limitations on actions ``(a) Criminal Proceedings.--No criminal proceeding shall be maintained under this chapter unless it is commenced within three years after the cause of action arises. ``(b) Civil Actions.--No civil action shall be maintained under this chapter unless it is commenced within three years after the cause of action arises or claim accrues. ``(c) Additional Limitation.--No criminal or civil action shall be maintained under this chapter for the extraction or use of all or a substantial part of a collection of information that occurs more than 15 years after the investment of resources that qualified the portion of the collection of information for protection under this chapter that is extracted or used.''. SEC. 3. CONFORMING AMENDMENT. The table of chapters for title 17, United States Code, is amended by adding at the end the following: ``12. Misappropriation of Collections of Information........ 1201''. SEC. 4. CONFORMING AMENDMENTS TO TITLE 28, UNITED STATES CODE. (a) District Court Jurisdiction.--Section 1338 of title 28, United States Code, is amended-- (1) in the section heading by inserting ``misappropriations of collections of information,'' after ``trade-marks,''; and (2) by adding at the end the following: ``(d) The district courts shall have original jurisdiction of any civil action arising under chapter 12 of title 17, relating to misappropriation of collections of information. Such jurisdiction shall be exclusive of the courts of the States, except that any action against a State governmental entity may be brought in any court that has jurisdiction over claims against such entity.''. (b) Conforming Amendment.--The item relating to section 1338 in the table of sections for chapter 85 of title 28, United States Code, is amended by inserting ``misappropriations of collections of information,'' after ``trade-marks,''. (c) Court of Federal Claims Jurisdiction.--Section 1498(e) of title 28, United States Code, is amended by inserting ``and to protections afforded collections of information under chapter 12 of title 17'' after ``chapter 9 of title 17''. SEC. 5. EFFECTIVE DATE. (a) In General.--This Act and the amendments made by this Act shall take effect on the date of the enactment of this Act, and shall apply to acts committed on or after that date. (b) Prior Acts Not Affected.--No person shall be liable under chapter 12 of title 17, United States Code, as added by section 2 of this Act, for the use of information lawfully extracted from a collection of information prior to the effective date of this Act, by that person or by that person's predecessor in interest. Passed the House of Representatives May 19, 1998. Attest: ROBIN H. CARLE, Clerk.

Collections of Information Antipiracy Act - Amends Federal copyright law to make persons who extract, or use in commerce, a substantial part of a collection of information gathered or maintained by another person through the investment of substantial resources, so as to harm the other person's (or a successor's) actual or potential market for a product or service that incorporates such information and is offered or intended to be offered in commerce liable to the person (or a successor) for remedies under this Act. Exempts certain activities from this Act, including the extraction or use of individual items of information or extraction or use of information for verification, nonprofit educational, scientific, or research, or news reporting purposes. Provides that protection shall not extend to information gathered or maintained by or for a government entity or to computer programs. Protects information required to be collected and disseminated by a national securities exchange, a registered security association, or a registered securities information processor under the Securities Exchange Act of 1934 or a contract market under the Commodity Exchange Act. Provides that information otherwise subject to protection is not disqualified from protection solely because it is incorporated into a computer program. Requires all rights specified in this Act to be governed exclusively by Federal law, thus preempting State law. Declares that protection under this Act is independent of, and does not affect or enlarge, any copyright protection in any work that is contained in or consists of a collection of information. Authorizes civil actions to be brought for violations of this Act. Provides for injunctions to prevent violations and authorizes impoundment of all copies of information extracted or used in violation. Entitles plaintiffs to specified monetary relief. Reduces or remits monetary relief for nonprofit educational, scientific, or research institutions in cases where an employee believed conduct to be permissible. Makes provisions regarding injunctions and impoundment inapplicable to actions against the U.S. Government. Provides for relief against State entities. Prescribes criminal penalties for certain willful violations. Provides for a three-year statute of limitations on civil and criminal actions. Bars the maintenance of actions for the extraction or use of a collection of information that occurs more than 15 years after the investment of resources that qualified the information for protection.

A 29-year-old Army veteran allegedly killed his mother and rode a tractor through his Simi Valley neighborhood, firing rounds, before police killed him Saturday. Detectives on Sunday were piecing together details about the incident. Jane Yamamoto reports from Simi Valley for NBC4 News at 11 p.m. on Sunday, Aug. 25, 2013. (Published Sunday, Aug. 25, 2013) A man fatally shot by police after he possibly killed his mother and rode through a neighborhood firing a gun from a tractor was identified on Sunday as a veteran of the U.S. Army. Ryan Carnan, 29, (pictured) was fatally shot by Simi Valley police officers on Saturday afternoon, officials said. Wild Standoff Ends with Gunman Dead Police in Simi Valley are now investigating the background of a man killed by officers after a wild standoff. Detectives believe the man killed his mother, then opened fire on others in her neighborhood while fleeing on a tractor. Jane Yamamoto reports for the NBC4 News at 8 p.m. on Sunday, Aug. 25, 2013. (Published Sunday, Aug. 25, 2013) The events prompted a bomb-squad callout and the evacuation of homes in the Bridal Path neighborhood of Simi Valley, 30 miles northwest of downtown Los Angeles. It started with a call to police from the suspect's brother about the killing of their mother, a house fire, the discovery of a woman's body inside the home and calls from residents reporting a man driving through on a tractor firing a gun. Police Kill Gunman, Find Mother's Body After Standoff Police fatally shot a gunman who was believed to have killed his own mother and ridden a tractor through a Simi Valley neighborhood, firing his weapon, Saturday night. Jane Yamamoto reports from Simi Valley for NBC4 News at 11 p.m. on Saturday, Aug. 24, 2013. (Published Saturday, Aug. 24, 2013) He reportedly aimed the gun at residents he encountered on the street. The identity of the woman and the cause of her death have not been confirmed, police said. But police said they believe it's Carnan's mother - an administrator at Santa Susana High School. Southern California Police Standoffs An autopsy was scheduled to be performed on the victim Monday. Police shot the suspect when "the officers were confronted with a deadly force situation," the Simi Valley Police Department said in a press release. "Based on the information that was being received by the 911 callers that a subject was actively shooting a firearm in a residential neighborhood, the heroic actions of the officers involved cannot be understated," the press release said. Residences in the area were evacuated as a precaution as a bomb squad checked the home after the fire was put out. The officers are home on paid administrative leave pending the outcome of parallel probes into the shooting by the Simi Valley Police Department and the Ventura County District Attorney’s Office. More Southern California Stories: ||||| advertisement Grief counselors were expected Monday to arrive at a Southern California high school to help students and staff cope with the death of an employee who was killed allegedly by her son who was fatally shot by police. Mourners placed flowers outside Santa Susana High School for Sally Carnan, who worked in the attendance office at the Ventura County school. "We loved her. Everyone loved her," said Cassie Sadowsky, a former student, of the 67-year-old woman affectionately known as "The Attendance Lady." Carnan's son, Ryan, allegedly killed his mother, set their house on fire, then fired at neighbors and police from a tractor before he was fatally shot by officers on Saturday, authorities said. His mother's body was found inside the home, police said. Autopsies to reveal details about the deaths were set for Monday. Carnan, 29, (pictured) had no criminal record with Simi Valley police, officials said. But police were called to the house at least five times, the most recent in 2008. "Those were mental-health related calls," said Cmdr. Stephanie Shannon, of the Simi Valley Police Department. A family friend said Ryan Carnan was discharged from the U.S. Army five years ago, around the same time his father died of cancer. Results from an request with the military were not immediately available. "They 're kinda overcome with everything that's happened," said Brandon Lyman, the family friend. The incident Saturday started with a call from Ryan Carnan's brother to police, saying Ryan Carnan brother shot their mother, police said. The call prompted a call to the fire department and a bomb-squad, fearing incendiary devices and the evacuation of homes in the Bridal Path neighborhood of Simi Valley, 30 miles northwest of downtown Los Angeles. Ryan Carnan lived with his mother at a home nearby on Mellow Lane. He reportedly aimed the gun at residents and police from a tractor, officials said. Police shot Ryan Carnan when they said they were confronted with a "dangerous and deadly situation." The officers are home on paid administrative leave pending the outcome of parallel probes into the shooting by the Simi Valley Police Department and the Ventura County District Attorney’s Office. More Southern California Stories:

– A 29-year-old Army veteran allegedly murdered his mother, set her house on fire, and then fired at residents in Simi Valley, Calif., while driving a tractor before being shot dead by police Saturday, NBC Los Angeles reports. Police were alerted to the situation by Ryan Carnan's brother, who reported their mother had been killed, and by neighborhood residents who spotted a shooter atop a tractor. ABC 7 reports that Carnan allegedly shot at a bicyclist as well as others; police say they shot Carnan after he opened fire on them. Carnan's brother told authorities his brother confessed to shooting and killing their mother, whose body was found inside the burning home, though her cause of death has not been officially verified. No one else was injured. Police aren't sure of Carnan's motive or what led up to the shootings. He had been stationed in Korea at some point, and police had been called to the family home three times over concerns about his mental health, though the last of those calls reportedly occurred five years ago. NBC Los Angeles notes that Sally Carnan was a beloved employee of Santa Susana High School, where she was known as the "Attendance Lady."

SECTION 1. SHORT TITLE. This Act may be cited as the ``Reform Americans Can Afford Act of 2010''. SEC. 2. FINDINGS. Congress finds the following: (1) The nonpartisan Congressional Budget Office (referred to in this section as the ``CBO'') predicts that health insurance premiums will increase by $2,100 for millions of families by 2016 as a result of the Democrats' health overhaul. (2) The Obama Administration's own actuaries at the Centers for Medicare & Medicaid Services (referred to in this section as the ``CMS'') predict that, ``[N]ational health expenditures under the health reform act would increase by a total of $311,000,000,000 (0.9 percent) during calendar years 2010- 2019'' as a result of the Democrats' health overhaul. (3) The CMS actuaries predict that 14,000,000 Americans would lose their employer-sponsored insurance as a result of the Democrats' health overhaul. (4) The Democrats' health overhaul penalizes Americans who save money to pay for their health care and threatens to reduce the value of the health benefits of 43,000,000 Americans with Flexible Spending Arrangements and Health Savings Accounts. (5) CBO estimates the Democrats' health overhaul slashes Medicare by more than one-half trillion dollars in order to fund a new Government entitlement program. (6) The Medicare actuaries found these Medicare cuts to be so drastic that they caution, ``providers for whom Medicare constitutes a substantive portion of their business could find it difficult to remain profitable and, absent legislative intervention, might end their participation in the program (possibly jeopardizing access to care for beneficiaries)''. (7) The CMS actuaries predict 7,000,000 Medicare beneficiaries will no longer be enrolled in a Medicare Advantage plan and millions of seniors who are currently enrolled in a Medicare Advantage plan will see their benefits slashed and out-of-pocket costs increase. (8) According to the Joint Committee on Taxation and the CBO, the Democrats' health law contains a total of $569,200,000,000 in tax increases, including a dozen separate provisions that break President Obama's pledge to avoid tax increases on middle-class Americans earning less than $200,000 per year and families earning less than $250,000 per year. (9) The national unemployment rate remains near 10 percent. (10) CBO estimates that the Democrats' health overhaul will raise taxes on employers who fail to provide Government- approved health insurance to their employees by $52,000,000,000. (11) CBO said that ``employees largely bear the cost of . . . [employer mandate] fees in the form of lower wages''. (12) The costs incurred by businesses who avoid the tax by complying with the employer mandate may also be felt by potential workers (who will have fewer employment opportunities as businesses respond to the mandate by reducing additional hiring) and by consumers (who may have to pay more for goods and services to offset the higher costs imposed on businesses by the mandate). (13) The U.S. Chamber of Commerce, which represents more than 3,000,000 businesses and organizations, said the Democrats' health overhaul, ``will not increase coverage-rather it will lead to out-sourcing, off-shoring, hiring of independent contractors, spinning-off small new companies, reducing workforces, and reducing wages''. (14) The National Federation of Independent Business, which represents 350,000 small businesses, said through mandates, ``employees ultimately bear the cost of their health insurance through lower employment, depressed wages, depressed productivity, and loss of economic opportunities''. (15) CBO found that 3,900,000 Americans would pay $17,000,000,000 in taxes for not purchasing Government-approved health insurance and that nearly half of these taxes would be paid by families earning less than 300 percent of the Federal poverty level. (16) The Internal Revenue Service may have to hire as many as 16,500 additional agents, auditors, and other workers to enforce all the new taxes and penalties in the Democrats' health overhaul, dangerously expanding the Government's reach into the lives of virtually every American. (17) The CMS actuaries predict the nearly $110,000,000,000 in new health care industry taxes in the Democrats' health overhaul will be passed onto consumers in the form of higher premiums and out-of-pocket costs. (18) The subsidies for individuals and families (who earn less than 400 percent of the Federal poverty level) in the Democrats' health overhaul are structured in a way that will financially punish married couples. For example, a woman earning $32,000 in 2016 who gets married to a man earning the same amount will pay an average marriage penalty of $9,640 versus what they would have paid for health coverage had they not married. (19) The rapid phase-out of the premium tax credits, when combined with existing income and payroll tax rates, create effective marginal tax rates exceeding 100 percent in certain cases, thus destroying any incentive to work harder and earn more income. (20) The so-called ``Patient-Centered Outcomes Research Institute'' paves the way for Government-sanctioned rationing of life-saving treatments by allowing the coverage of health care treatments and services to be based on how much those treatments and services cost. (21) The CMS actuaries predict the program to help cover the sickest Americans will be so inadequately funded that premiums will have to increase ``substantially'' to maintain solvency. (22) The CMS actuaries estimate 18,000,000 Americans will be dumped into Medicaid, a program in which they are likely to have a difficult time finding a doctor to treat them, as a result of the Democrats' health overhaul. (23) The Medicaid expansion in the Democrats' health overhaul will force States to spend an additional $20,000,000,000 on their Medicaid programs at time where the vast majority of States are facing a budget crisis. (24) The 2010 budget deficit currently stands at $1,400,000,000,000 and the national debt totals $12,000,000,000,000. (25) The CMS actuaries exposed the Democrats' budget gimmicks, saying a new Government-run long-term care program that Democrats have touted as saving $72,000,000,000 over the next ten years will ``face a significant risk of failure'' and also that ``the improved [Medicare] financing cannot be simultaneously used to finance other Federal outlays (such as the coverage expansions) and to extend the trust fund''. (26) CBO estimates the House Republican health reform bill would reduce premiums across the board by up to $1,050 annually. (27) The House Republican health reform bill would not cut Medicare or increase taxes. (28) CBO estimates the Republican health reform bill would reduce the Federal deficit by $68,000,000,000 over the next 10 years. (29) As of introduction of this bill, 21 State attorneys general are suing the Federal Government, challenging the constitutionality of the Democrats' new health care law. SEC. 3. REPEAL OF THE PATIENT PROTECTION AND AFFORDABLE CARE ACT AND THE HEALTH CARE AND EDUCATION RECONCILIATION ACT OF 2010. (a) Patient Protection and Affordable Care Act.--Effective as of the enactment of the Patient Protection and Affordable Care Act, such Act is repealed, and the provisions of law amended or repealed by such Act are restored or revived as if such Act had not been enacted. (b) Health Care and Education Reconciliation Act of 2010.-- Effective as of the enactment of the Health Care and Education Reconciliation Act of 2010, such Act is repealed, and the provisions of law amended or repealed by such Act are restored or revived as if such Act had not been enacted. SEC. 4. ENACTMENT OF THE COMMON SENSE HEALTH CARE REFORM AND AFFORDABILITY ACT. H.R. 4038, entitled the ``Common Sense Health Care Reform and Affordability Act'', as introduced in the House of Representatives on November 6, 2009, is enacted into law.

Reform Americans Can Afford Act of 2010 - Repeals the Patient Protection and Affordable Care Act and the Health Care and Education Reconciliation Act of 2010, effective as of their enactment. Restores provisions of law amended by such Acts. Enacts the Common Sense Health Care Reform and Affordability Act (H.R. 4038), as introduced in the House of Representatives on November 9, 2009.

for systems in thermodynamical equilibrium the occurrence of phase transitions can be inferred from a change in the behavior of the thermodynamic potentials ( or its derivatives ) as a function of an intensive variable . for instance , divergences or abrupt changes in the heat capacity @xmath0 are indicators for most first - order phase transitions . in systems subject to extreme nonequilibrium conditions like excitation with an intense femtosecond laser , neither thermodynamic functions nor intensive variables are well defined . however , a large variety of nonequilibrium phase transitions can be induced by femtosecond laser pulses , as has been demonstrated both experimentally and theoretically @xcite . such ultrafast phase transitions are detected indirectly by time - dependent changes of the optical properties @xcite or directly by _ post mortem _ analysis @xcite and recently through more direct measurements using ultrashort x - ray pulses @xcite . in a recent experimental study , musella _ et@xmath1al . _ reported results on the excitation of graphite with very long pulses ( in the millisecond range ) . the thermogram recorded during the heating of the sample shows a sharp increase of the temperature slope at the melting point , which corresponds to changes in the energy absorption @xmath2 and heat conductivity upon melting . note that in these experiments , thermal equilibrium is reached during the excitation . note that in the case of femtosecond excitation @xmath3 is a physical quantity , whereas @xmath4 and @xmath5 are no longer well defined . the question which immediately arises from this analysis is : does @xmath3 show similar changes as @xmath6 in the case of thermal equilibrium when the system is illuminated by a femtosecond laser pulse ? in this paper we show that this is the case , and that @xmath7 exhibits dramatic changes as a function of laser intensity @xmath8 when the system undergoes an ultrafast phase transition . this leads to a natural generalization of `` heat capacity '' for laser induced nonequilibrium processes as @xmath9 . in sec . [ sec : theory ] we briefly review our method of calculating the structural response of covalent materials during and after intense laser excitation . in sec . [ sec : results ] we present results for diamond and graphite , concentrating on the efficiency with which energy is absorbed from the laser pulse . we show that the structural changes during the action of the pulse are particularly important for the understanding of the nonlinear dependence of the absorbed energy on the intensity of the pulse . as these structural changes occur on a time scale of approximately 100 fs the pulse duration is responsible for very different absorption behavior in the @xmath10 fs to @xmath11 fs pulse duration range . finally , in sec . [ sec : summary ] we summarize our results . the calculation of the energy absorption of covalent solids is based upon a theory for the analysis of laser induced ultrafast processes in solids . the theory employs a molecular dynamics method on the basis of an electronic tight - binding hamiltonian . this real - space calculation takes into account all atomic degrees of freedom . special attention is paid to the strong nonequilibrium created in the electronic system by the ultrashort laser pulse . a method of calculating nonequilibrium occupation numbers for the energy levels of the system leads to a molecular dynamics calculation on time - dependent potential energy surfaces . this approach provides a theoretical framework for the treatment of strong nonequilibrium situations in materials where atomic and electronic degrees of freedom play an equally important role . in this theory trajectories for laser induced structural changes are determined by molecular dynamics simulations for which we calculate forces from the hamiltonian @xmath12 the second term contains a repulsive potential @xmath13 that takes care of the repulsion between the ionic cores , and the first term is a tight - binding hamiltonian @xmath14 here , the first term is the on - site contribution . in the second term , the @xmath15 are the hopping integrals , and @xmath16 and @xmath17 are creation and annihilation operators for an electron at site @xmath18 or @xmath19 in orbitals @xmath20 or @xmath21 , respectively . from the hamiltonian , eq . ( [ eq : hamop ] ) , we calculate forces using the hellman - feynman theorem : @xmath22 here , @xmath23 stands for the eigenvector of the hamiltonian @xmath24 that corresponds to the eigenvalue @xmath25 . the special feature of the theory which makes it applicable to optically excited materials is contained in the time dependent occupation numbers @xmath26 for the energy levels @xmath25 of the system . while in thermal equilibrium these occupation numbers are calculated from a fermi - dirac distribution function @xmath27 at a given electronic temperature @xmath28 , electronic nonequilibrium is accounted for by solving equations of motion for the occupation of electronic states : @xmath29 \biggr\ } \\ & - \frac{n(\epsilon_m , t ) - n^0(\epsilon_m , t_{\rm e})}{\tau_1 } \ , . \end{split}\ ] ] thus , the electronic distribution is at each time step folded with the pulse intensity function @xmath30 . this means that at each time step , the occupation of an energy level @xmath25 changes in proportion to the occupation difference with respect to levels at @xmath31 and at @xmath32 . in eq . ( [ eq : absorpthermal ] ) , constant optical matrix elements are assumed . the second term of eq . ( [ eq : absorpthermal ] ) describes the electron - electron collisions that lead to an equilibration of the electronic system with a rate equation of the boltzmann type for the distribution @xmath26 . hence , with a time constant @xmath33 , the distribution @xmath26 approaches a fermi - dirac distribution @xmath34 . the electron temperature @xmath28 that results from the electron thermalization will not remain constant over time , but will decrease due to electron - phonon coupling and to diffusion of hot electrons out of the laser excited region of the solid into colder areas . in the regime of an excitation of typically 10 % of the valence electrons into the conduction band for which this theory is intended no precise knowledge about thermal conductivity of the electrons and electron - phonon coupling constants is available . thus , a relaxation time @xmath35 which characterizes the time scale of the total decrease of the electron temperature by both the electron - phonon and by the hot electron diffusion processes is assumed : @xmath36 this simple relaxation time approach has the advantage that the time scale @xmath35 on which the electron - lattice equilibration takes place can be taken from experiment . the forces given by eq . ( [ eq : forces ] ) can now be used to solve the equations of motion for the atoms numerically . in the case of a bulk system , a constant pressure molecular dynamics ( md ) scheme is used . this is based on a lagrangian which contains the shape and size of the molecular dynamics supercell as additional degrees of freedom @xcite : @xmath37 the first term is the kinetic energy of the atoms , with the coordinates of the atoms @xmath38 written in terms of the relative coordinates @xmath39 and the @xmath40-matrix @xmath41 that contains the vectors spanning the md supercell ; @xmath42 are the relative velocity vectors , and t denotes transposition . @xmath43 is the potential which is calculated from a tight - binding formalism as explained above . the terms in the lagrangian of eq . ( [ eq : lagrange ] ) which are responsible for the simulation of constant pressure are an additional kinetic energy term @xmath44 for which the simplest form is @xmath45 @xcite , and @xmath46 is an additional potential term which describes the effect of an isotropic external pressure @xmath47 ; @xmath48 is the volume of the md supercell . the equations of motion are derived from eq . ( [ eq : lagrange ] ) by the euler - lagrange formalism , and they are integrated numerically with the velocity form of the verlet algorithm @xcite . the dependence of the absorption of energy on the laser pulse intensity and duration shows an interesting behaviour . the following results have been calculated in the bulk and for constant pressure . diamond and graphite samples of @xmath49 atoms per md supercell were thermalized to a temperature of @xmath50 k by simulated annealing before absorbing laser pulses of a wide range of intensities and durations . results for absorption of carbon in its diamond structure are shown in fig . [ fig : diamond_absorption ] . every square ( @xmath51 ) corresponds to a calculated trajectory . note , the lines connecting the dots are drawn to guide the eye . the graph represents the actual absorbed energy in units of electron volts per atom as a function of the laser intensity for different pulse durations . this quantity is denoted here as the `` offered '' energy . it is the energy that would have been absorbed by the system , if no structural changes had taken place . thus , the `` offered '' energy is determined by performing the calculation of energy absorption for fixed atomic coordinates . note , structural distortions change the electronic structure of the material and consequently the absorption characteristics . fs to @xmath52 fs . the shape of the absorption curves and their ordering with respect to the pulse duration can be understood from the time - dependent changes of the dos . each of the results ( @xmath51 ) corresponds to a calculated trajectory . , title="fig:",scaledwidth=47.0% ] + a general trend shared by all but the @xmath53 fs to @xmath11 fs curves in fig . [ fig : diamond_absorption ] is a moderate , linear increase of absorption with intensity up to an absorbed energy of roughly @xmath54 ev / atom . then a sharp increase of absorption until approximately @xmath55 ev / atom occurs . then we find again a moderate linear increase of absorption with laser intensity . the results show that the absorption increases more sharply with increasing pulse duration . with increasing duration of the laser pulse , the laser intensity for which the sharp increase in absorption occurs decreases significantly . the curves for long pulse durations are even characterized by the absence of an initial weak increase of absorption with intensity . in fig . [ fig : d64tn350_absorption ] we show the absorbed energy of diamond as a function of time . the laser pulse duration was @xmath56 fs . this figure serves as an example to clarify how the form of the absorbed energy curves of fig . [ fig : diamond_absorption ] comes about . [ fig : d64tn350_absorption ] is directly related to the @xmath57 fs curve of fig . [ fig : diamond_absorption ] : each final absorbed energy at @xmath58 fs in fig . [ fig : d64tn350_absorption ] corresponds to a result ( @xmath51 ) in the @xmath57 fs curve of fig . [ fig : diamond_absorption ] . absorption of trajectories with different final states are shown . the dashed lines correspond to the absorption that is expected if no structural changes occur during the action of the pulse . , title="fig:",scaledwidth=47.0% ] + fig . [ fig : d64tn350_absorption ] shows the absorbed energy for four different intensities . the final state of the material is indicated . the lowest pulse intensity does not lead to structure changes , due to the two medium intense pulses , the diamond structure is damaged , and the strongest pulse leads to ablation of the material . in fig . [ fig : d64tn350_absorption ] the absorption that would have been expected if no structural changes had occurred during the action of the laser pulse is indicated by dashed lines . we observe that the deviation of the energy actually absorbed by the material from the expected value increases with increasing pulse intensity . in the case of the trajectory where diamond remains unchanged , the actual absorption is very close to the expected value . however , in trajectories where structural damage or even ablation is observed the actual absorption sharply deviates from the expected absorption . the cause for this sharp deviation will be explained with the help of the densities of states shown in fig . [ fig : d64tn350z.dos ] . they correspond to the curve of fig . [ fig : d64tn350_absorption ] with the second - highest absorbed energy . in fig . [ fig : d64tn350z.dos ] ( a ) the dos before the laser pulse at @xmath59 fs is shown ; the time is measured with respect to the maximum of the laser pulse of @xmath60 fs duration . the dos corresponds to diamond at @xmath61 k. the dos in fig . [ fig : d64tn350z.dos ] ( b ) is taken at @xmath62 fs which corresponds to the time of the sharp bend in fig . [ fig : d64tn350_absorption ] . in the dos , the emergence of states in the @xmath63 ev gap of diamond can be observed . this explains the strong increase in absorption . [ fig : d64tn350z.dos ] ( c ) shows the dos at @xmath64 fs . at this time the intensity of the laser pulse has already decreased significantly from its maximum value , but in the dos , states have completely filled the diamond gap , and the absorption of the material is far stronger than before the pulse . this figure corresponds to the trajectory with the second highest absorbed energy of fig . [ fig : d64tn350_absorption ] . for a discussion of the features of the dos , see the text . , title="fig:",scaledwidth=47.0% ] + an explanation of the overall behaviour of the absorption in the material must be given by the time - dependent changes in the density of states . note , this is the main material property taken into account in the treatment of the absorption . this time dependency of the dos is caused by the structural changes induced by the laser pulse . inspection of the trajectories shows that the sharp bend of the graphs close to an absorbed energy of @xmath54 ev corresponds to the damage threshold of the material . the damage ( disorder ) causes the @xmath65 ev gap present in diamond to be filled with states until the gap - less dos is reached . for pulses that are long enough to permit the structural changes to occur before the intensity has fallen off completely , the electronic states that fill the gap of diamond will enormously increase the absorption of the material the @xmath10 fs graph shows only a slight increase of the absorption above the damage threshold , because the pulse has already run out before essential changes in the structure have taken place . on the other hand , the @xmath53 fs to @xmath11 fs graphs show an absorption growing sharply with pulse intensity , because all structural changes induced by the laser can take place while the pulse intensity is still high . thus , the changed dos has a strong influence on the energy that can finally be absorbed from the pulse . in fig . [ fig : graphite_absorption ] , the absorption behaviour for a graphite sample is shown . the data are presented in the same way as in fig . [ fig : diamond_absorption ] . for graphite , the absorption for a given pulse duration depends on the pulse intensity in a fashion similar to that found in diamond . again , a strong increase of absorption takes place at the damage threshold , which in graphite is found to be at roughly 3 ev . at this threshold , melting of graphite and the destruction of the graphite planes takes place . at lower intensities , absorption shows a moderate , linear increase with laser intensity . however , an important difference can be observed in the ordering of the curves . in the case of graphite , the slope of the absorption curves is lower for higher pulse durations . interpreting this with the help of the density of states , we find that structural relaxation taking place during the pulse decreases the density of states close to the fermi level and thus prevents absorption of energy from the laser pulse . a physical picture for this effect can be derived from the bonding character : vibrational excitation of the graphite planes causes atoms to be displaced perpendicular to the plane , and thus the 3-dimensional distortion of the 2-dimensional graphite structure causes the pure @xmath66 bonding of graphite to be modified with an addition of @xmath67 bonding . fs to @xmath68 fs . note , the ordering of the curves with respect to pulse duration shows a behaviour different from diamond , which reflects a different time development of the dos during the pulse . each of the results ( @xmath51 ) corresponds to a calculated trajectory . , title="fig:",scaledwidth=47.0% ] + in fig . [ fig : c64tn350_absorption ] we show the absorbed energy of graphite as a function of time . the pulse duration was @xmath69 fs . three low laser intensities produced no change in the graphite structure , while a fourth pulse leads to ablation of the material . for comparison , the absorbed energy that would be expected if no structural change took place during the action of the pulse is shown with dashed lines . as in the case of diamond ( compare fig . [ fig : d64tn350_absorption ] ) with increasing pulse intensity the deviation of the actual absorbed energy from the expected value becomes more pronounced . absorption of trajectories with different final states are shown . the dashed lines correspond to the absorption that is expected if no structural changes occur during the action of the pulse . , title="fig:",scaledwidth=47.0% ] + in order to analyze the cause of the increased absorption of energy we show in fig . [ fig : c64tn350d.dos ] selected densities of states during the action of the laser pulse . these densities of states correspond to the trajectory with the highest absorbed energy in fig . [ fig : c64tn350_absorption ] . at @xmath59 _ i.@xmath1e . _ 700 fs before the laser pulse maximum , the dos is that of graphite at @xmath50 k. at @xmath70 fs the overall width of the dos has decreased while the dos close to the fermi level has increased . at @xmath71 fs , a very high dos around the fermi level has developed , indicating a metallic liquid phase of the material . this explains the strong increase of absorption during the action of the laser pulse . in fig . [ fig : space_absorption ] we show a consequence of the behaviour of the absorbed energy for the spatial absorption profile of diamond . typically , a laser pulse has a gaussian profile in space . the different absorbed energies that result as a consequence of structural changes in the material during the action of the pulse leads to the spatial absorption profile shown in fig . [ fig : space_absorption ] . it is remarkable that the profile of the absorbed energy is much steeper than the profile of the pulse . this may be of importance in the interpretation of ablation experiments . in the introduction we have suggested characterizing the energy absorption behavior of a system in strong nonequilibrium by a generalized `` heat capacity '' defined as @xmath9 . we illustrate this concept in fig . [ fig : absorption_deriv ] in the case of diamond . the derivative of the absorbed energy with respect to `` offered '' energy is plotted as a function of `` offered '' energy . as explained above we define the `` offered '' energy as the energy that would be absorbed by the system if no structural changes occurred during the action of the pulse . thus , the `` offered '' energy is proportional to the laser intensity @xmath8 and the quantity @xmath72 shown in fig . [ fig : absorption_deriv ] is proportional to @xmath9 . the behavior of this quantity shows a peak which is most pronounced for long pulse durations ( see fig . [ fig : absorption_deriv ] ) . the peak position corresponds to the laser intensity which induces changes in the structure and in the dos of the material that are most suitable to enhance the absorption of energy . to the left of the peak , the laser is not strong enough to induce structural changes in the material while the pulse is still active . to the right of the peak , the laser intensity is so high that evaporation of the material sets in during the action of the pulse which leads to decreased absorption of energy . this figure corresponds to the trajectory with the highest absorbed energy of fig . [ fig : c64tn350_absorption ] . for a discussion of the features of the dos , see the text . , title="fig:",scaledwidth=47.0% ] + fs . the spatial profile of the `` offered '' laser energy is typically given by a gaussian ( dashed line ) . considering the relation between `` offered '' energy and absorbed energy in diamond for laser pulses of @xmath60 fs duration ( see fig . [ fig : diamond_absorption ] , we find an absorption profile that differs significantly from a gaussian ( solid line ) . , title="fig:",scaledwidth=47.0% ] + . note that the functions corresponding to all pulse durations between @xmath10 fs and @xmath73 fs have been multiplied by a factor 30 for clarity . , title="fig:",scaledwidth=47.0% ] + we have calculated the absorption of energy from intense laser pulses in diamond and graphite . an interesting nonlinear dependence of the absorbed energy on the laser intensity is observed . analysis of the density of states of the materials at different times during the action of the laser pulse shows that an enhanced absorption of energy is due to ultrafast changes in the dos which in turn are caused by the structural relaxation of the excited material setting in during the action of the exciting pulse . as these structural changes occur on a time scale of approximately 100 fs the pulse duration plays an important role in determining the influence of the structural relaxation on the absorption behavior . in summary , the results show the dependence of absorption on the light pulse form and the occurring structural changes of these materials . these results may also depend on the frequency and polarisation of the laser pulse . nevertheless , the fact that nonthermal processes may occur during the action of the laser pulse and thus change the absorption of the material is of general validity . if we compare the theoretical result for the dependence of absorbed energy on pulse intensity for graphite ( see fig . [ fig : graphite_absorption ] ) with the experimental result of ronchi _ et al . _ @xcite we find a surprising similarity . although the pulse duration @xmath74 ms in the experiment was far higher than that considered in the calculation , the increase of absorption at the melting point should have a similar explanation as the increase of absorption at the damage threshold in the calculation . it is remarkable that the effect reported by ronchi _ et al . _ is also present for ultrashort laser pulses . this work has been supported by the deutsche forschungsgemeinschaft through sfb 450 . our simulations were done on the cray t3e at konrad - zuse - zentrum fr informationstechnik berlin . k. sokolowski - tinten , j. bialkowski and d. von der linde , phys . b * 51 * , 14186 ( 1995 ) . k. sokolowski - tinten , j. solis , j. bialkowski , j. siegel , c. n. afonso and d. von der linde , phys . lett . * 81 * , 3679 ( 1998 ) .

the ultrafast time - dependence of the energy absorption of covalent solids upon excitation with femtosecond laser pulses is theoretically analyzed . we use a microscopic theory to describe laser induced structural changes and their influence on the electronic properties . we show that from the time evolution of the energy absorbed by the system important information on the electronic and atomic structure during ultrafast phase transitions can be gained . our results reflect how structural changes affect the capability of the system to absorb external energy . 2

Following a string of incidents that spurred calls for a boycott, Waffle House is again facing scrutiny for calling the police on its customers. Police body-camera footage posted to Facebook by activist and the Intercept columnist Shaun King shows two black customers at a Fort Walton Beach, Florida, location being handcuffed after complaining to waitstaff that they were overcharged for a beverage. According to King, the couple being handcuffed in the video “refused to pay for a $1.50 overcharge on an orange juice that was listed as $1 on the menu.” After arguing with staff about the price, police were called. The couple ultimately paid for their meals and were not taken into custody, according to Business Insider, which also states that ”the woman returned to the Waffle House location later and received a full refund.” Police body camera footage of wrongful arrest of Black couple at Waffle House Here is the horribe body camera footage of this wrongful, illegal arrest at Waffle House. This Black couple was arrested for theft and trespassing. No, they didn't eat the food and refuse to pay. They never even received the damn food. In fact, their money is on the counter as they are being arrested. The man being arrested here refused to pay for a $1.50 overcharge on an orange juice that was listed as $1.00 on the menu. That's all. When they refused to change the charge he demanded to talk to customer service. Waffle House called the police. The couple never stole a thing. Listen to me. Don't you dare go to Waffle House. And shame on the Fort Walton Beach Police Department for this wrongful arrest. Shame on them. Posted by Shaun King on Wednesday, June 13, 2018 King’s Facebook post on the incident has nearly 1,000 comments, with many urging people to avoid patronizing the Georgia-based diner chain. “Waffle House has not changed and we continue to go there, that’s why they won’t change and why we continue to be disrespected,” one commenter writes. “Waffle House needs to learn some customer service,” says another commenter. “A normal restaurant would not call the cops on customers over $1.50. A good manager would acknowledge the mistake in prices and be done with it! There is no explanation or excuse for calling police in this situation!” In April, customer Chikesia Clemons was tackled and arrested at a Waffle House in Alabama after refusing to pay an extra 50 cents for utensils. The following month, 22-year-old Anthony Wall was choked and slammed to the ground by a police officer at a Waffle House in North Carolina after sitting at a table that waitstaff hadn’t yet cleaned. “With respect to the Saraland, Alabama, and Warsaw, North Carolina, incidents, we concluded that our employees acted appropriately by calling the police in light of safety concerns for our customers and themselves,” the chain said in a statement. “In the Fort Walton Beach, Florida, incident, our review of the matter is continuing.” Waffle House says it has tried to contact the female customer in the latest video “several times” as part of its investigation process, but has not gotten a response. Waffle House employees are trained to call the police “anytime there is concern about their personal safety or that of their customers,” a company spokesperson told the Atlanta Journal-Constitution following the incident in Alabama. Waffle House’s handling of such matters stands in stark contrast to Starbucks: Following an April incident in a Philadelphia store in which two black men were arrested while waiting for a friend to arrive, the coffee giant swiftly apologized and later shut down its U.S. stores for an afternoon of racial bias training to prevent similar incidents going forward. Starbucks has since given its employees new guidance on when it’s appropriate to call 911 on customers; such instances include customers being “unreasonably noisy, viewing inappropriate media, verbally abusing people, making unwanted sexual advances and indecent exposure.” • Waffle House Under Fire After Latest Viral Arrest Footage [Business Insider] • Bernice King Urges Waffle House Boycott Following Violent Incidents [E] • Violent Arrest of Black Woman at Waffle House Sparks Protests [E] ||||| The Waffle House restaurant chain has become the target of a boycott campaign in recent weeks, following several incidents in which employees called the police on black customers. Now, the chain is embroiled in a new controversy, after a video showing police handcuffing a black couple who had disputed the cost of a drink went viral. In the early hours of May 2, the couple, identified as Donald Copeland and Ms. Hart in a police report, placed a to-go order at a Waffle House in Fort Walton Beach, Florida. Before getting their food, they noticed that they were being charged more for one of the items than the price listed on the menu. The couple asked an employee about the charges, said that they would not pay the additional amount, and attempted to call the chain’s corporate headquarters. The employee responded by calling the police, later telling the officers they wanted to press charges if the couple did not pay. After a lengthy interaction with officers, the two were placed in handcuffs. “We haven’t been served at all. We haven’t been served so how is it theft? We asked her to explain the bill to us; she gave us no food or nothing and called you guys,” Hart says in the video. The incident comes amid an ongoing conversation about racial profiling and the mistreatment of black people in public places like restaurants and retail stores. And Waffle House restaurants have been the scene of such encounters on more than one occasion. The dispute started over a $2.50 charge for orange juice Body camera footage of the incident shows police interacting with Copeland and Hart. The video begins when police arrive at the Waffle House, and one officer calls for Copeland to come outside. When Copeland looks at the officer, saying something about police “putting hands on me,” the officer quickly responds. “Oh, I’m going to put my hands on you?!” the officer says. “Get out of here. You want to trespass?” As officers continue to insist that Copeland come outside, the man begins recording with his cell phone. He then passes the phone to Hart as he walks out of the restaurant. For several minutes after, Copeland and Heart argue with the officers. Officers tell Copeland and Hart that they will go to jail unless they pay their bill, at one point asking an employee if they want to press charges. Copeland can be seen attempting to tell officers that he has not actually been given the food they want him to pay for. The police had their Tasers drawn during parts of the exchange. Hart and Copeland are eventually placed in handcuffs. “The problem is you guys want to run your mouth,” one officer says later in the video. “Right when I walk in the door, he wants to start talking about ‘you guys ain’t gonna put your hands on me.’ Okay, I’m trying to talk to him like a man to see what’s going on, but he wants to start saying stuff like that. And then you want to pull your phone, which that’s fine, you’ve got the right to record ... but what you did, the crime that you and your boyfriend or your husband committed is you didn’t pay your bill.” They were later released from custody without charges after they agreed to pay and never return to the Waffle House where the incident occurred. According to reports, they were later given a full refund. Video of the incident went viral after the woman posted cellphone footage of the incident and spread further after activist and Intercept columnist Shaun King posted a clip of the couple’s police encounter on Twitter. Here is the body camera footage of this outrageous wrongful arrest of a Black couple @WaffleHouse. They were arrested for theft & trespassing. They never even received the food. They were overcharged a $1.50 for an orange juice and asked to call customer service. pic.twitter.com/c7a74NhKoH — Shaun King (@ShaunKing) June 13, 2018 In a Facebook post on Tuesday, the local police department defended itself, saying that officers had “followed proper protocol.” “We met with other interested parties in regard to this matter, and all parties involved determined that while there was no misconduct of the officers, that the situation could have been handled differently by both parties involved,” the post said. Calls to boycott Waffle House are increasing In April, a widely shared video showed a black woman, Chikesia Clemons, being violently arrested by police, while inside a Waffle House restaurant in Saraland, Alabama. Clemons was thrown to the ground and had her top pulled down by police after employees called 911, claiming that the woman had made threats while disputing a charge. At one point of the video, an officer can be heard telling Clemons “I’m about to break your arm.” One month later, video showed a 22-year old named Anthony Wall being choked by a police officer following a verbal dispute outside a North Carolina Waffle House. Wall said that employees called police because Wall, who had taken his sister to prom that evening before going with her to the restaurant, sat at a table that hadn’t been cleaned by waitstaff. After Clemons’s arrest, the Atlanta chapter of Black Lives Matter called for people to stage a nationwide sit in of the restaurant chain in early May. Public figures like Bernice King, daughter of Martin Luther King Jr., and actor Mike Colter, have also encouraged people to stop eating at the restaurant. Waffle House has repeatedly defended itself from criticism, saying that in many of these cases, employees were right to call police. “We understand the concern over these incidents, and welcome continued communication with the community, its leaders and the customers involved,” the chain said in a statement. “With respect to the Saraland, Ala., and Warsaw, N.C., incidents, we concluded that our employees acted appropriately by calling the police in light of safety concerns for our customers and themselves. In the Fort Walton Beach, Fla., incident, our review of the matter is continuing ... we hope that people will consider all the facts before making up their minds.” In a statement to CBS News, the company said it would “be doing additional training for the team members of this restaurant on the proper way to handle situations like this.” Their response stands in stark contrast to the reaction of other companies, like Starbucks. After two black men in a Philadelphia store were arrested in April, Starbucks announced a companywide racial bias training for some 175,000 employees. The coffee company also recruited several civil rights experts for the training, made the training materials available to other companies, and announced a number of in-store policy changes. ||||| Two black customers were reportedly handcuffed after complaining to Waffle House employees that they were overcharged. The Florida employees allegedly called the police after the couple “refused to pay for a $1.50 overcharge on an orange juice that was listed at $1 on the menu,” Intercept columnist Shaun King wrote on Facebook. WAFFLE HOUSE EMPLOYEE'S ACT OF KINDNESS TOWARD ELDERLY CUSTOMER LANDS HER $16G SCHOLARSHIP King shared a video of the police body camera footage, stating the couple was “arrested for theft and trespassing,” though he claims the pair never received the food and left money on the counter during the dispute. The Waffle House employees, King wrote, called police after the customer demanded to talk to management. In the body camera footage, the officer asks the couple to come outside while they are still arguing with the wait staff. Once outside, the couple tries to explain the issue with the bill, to which the police officer says they have to pay or they will be arrested for theft. The pair are eventually handcuffed, but both were released without being charged with anything. The pair paid for their meals, Business Insider reported, but the woman returned to Waffle House later and received a full refund. A spokesperson for Waffle House said they are looking into the incident. In a statement to Fox News, the restaurant said: "As anyone who has dined with us knows, we have a very diverse customer base and workforce. We have had a culture of inclusion since we opened our doors in 1955, and are very proud of the fact that our restaurants have been open to all. We understand the concerns that have been raised, and welcome continued communication with the community, its leaders and the customers involved. "While our review of the Fort Walton Beach, Fla., incident is continuing, we think both sides could have handled this situation better. On our part, our employee could have done more to de-escalate the dispute before calling the police. We have spoken to our employees in the restaurant and will be doing additional training for the team members of this restaurant on the proper way to handle situations like this. "The day after the incident, the customers came back to the restaurant and we gave them a full refund. Today, our CEO, Walt Ehmer, has called to apologize to Ms. Sheffield, who was one of the customers involved. We extend our apologies to all the customers who were in the restaurant that night." FOLLOW US ON FACEBOOK FOR MORE FOX LIFESTYLE NEWS This incident comes a month after a video of police choking a black Waffle House patron went viral on social media. In April, another incident made headlines when a black customer claimed she was locked out of Waffle House while white customers were allowed to eat.

– Waffle House says its CEO has apologized to a woman who was handcuffed along with her boyfriend over a dispute over a $1.50 charge at one of its restaurants. Activist Shaun King says the black couple were handcuffed after they "refused to pay for a $1.50 overcharge on an orange juice that was listed as $1 on the menu," Eater reports. Body-cam footage released by police in Fort Walton, Fla., shows the couple explaining that the restaurant charged them $2.50 for the orange juice. Officers, without talking to employees, told them they could be arrested for theft. "We haven't been served at all. We haven't been served so how is it theft? We asked her to explain the bill to us; she gave us no food or nothing and called you guys," the woman says. King says Waffle House employees called police after the man asked to talk to management, Fox reports. In the video, the couple—who had not received their food and insisted they were going to pay—are handcuffed after arguing with officers. They were eventually released without being arrested after saying they would pay their bill and not return to the outlet. Police say they believe proper protocol was followed, though Waffle House says it feels "both sides could have handled this situation better." The company says employees at the restaurant will receive additional training—and the couple were given a full refund the next day. Vox reports that the incident has added to calls to boycott the chain for being too quick to call the police on black customers. (The NAACP called an April arrest "troubling.")

osteonecrosis of the hip , previously named avascular necrosis , is a naturally progressive disease typically affecting young individuals ( the mean age approximately 35 years old ) ( 1 ) . it occurs when blood supply to the femoral head is disrupted , resulting in infarction and avascular necrosis of bone . several etiologies have been identified , such as trauma ( femoral neck fracture or posterior hip dislocation ) , blood disorders ( e.g. sickle cell anemia ) , and radiation therapy ( 2 , 3 , 4 ) . other important risk factors identified are the use of alcohol , use of corticosteroids ( e.g. in patients with systemic lupus erythematosus , or status - post renal transplant ) and cigarette smoking , as well as pregnancy ( 5 , 6 ) . having hiv has also been associated with an increased incidence of osteonecrosis of the femoral head , but it is unclear whether this is related to the virus or to the antiviral therapy ( 7 ) . much is still to be learned about the etiologies and the pathophysiology of this disease . when left untreated , 80% of clinically diagnosed cases of femoral head osteonecrosis will progress , most often incapacitating the patient due to pain and decrease in hip mobility ( 8) . the natural history of this condition is that it is usually initially confined to the superior weight - bearing portion of the femoral head , but progresses , rendering the area susceptible to collapse , and leading to subchondral fractures . eventually , degenerative changes of the hip joint ensue ( 9 ) . in the united states , the estimated incidence of this condition is 10,00030,000 per year , and 512% of all total hip arthroplasties are performed to treat patients with osteonecrotic hips . however , it is not appealing to the young and active patient population often affected by osteonecrosis of the hip , as they will most likely outlive their prosthesis and require revision . they are divided into external biophysical modalities ( extracorporeal shock - wave therapy , hyperbaric oxygen , or pulsed electromagnetic field ) and pharmacological therapies ( lipid - lowering agents , anticoagulants , or bisphosphonates ) . did a complete review of the english literature from 1960 to 1993 and found 21 studies where clinical outcomes of osteonecrotic hips treated non - operatively ( excluding electrical stimulation ) were evaluated ( 3 ) . pulsed electromagnetic field has been proven to result in clinical improvement and stabilization of osteonecrosis on radiographs by two studies done in the late 1980s , but this modality has never gained popularity ( 10 , 11 ) . also , new pharmacological measures as well as the use of growth and differentiation factors have shown potential in preventing and treating this disease , but clinical research projects are still awaiting long - term follow - up results to provide recommendations ( 4 ) . joint - preserving surgical procedures are presently the most commonly used approach to treatment of osteonecrotic hips . core decompression alone has the disadvantage of lacking subchondral support , whereas fibular grafting techniques have increased morbidity associated with graft harvest , longer operative time and blood loss , as well as rehabilitative complications ( 3 , 12 , 13 ) . the rationale for fibular bone - grafting is that it allows decompression of the femoral head as well as the removal of necrotic bone with its replacement by the graft . this graft plays the important role of providing structural support and scaffolding , facilitating repair and remodeling of subchondral bone ( 14 , 15 ) . since the main disadvantages of fibular grafting techniques are related to the bone - graft harvesting , the use of another material with characteristics similar to bone graft presents an interesting modality . porous tantalum is an expanded ( foam - like ) metal currently being used in several orthopedic procedures , namely hip and knee arthroplasty , spine surgery , and as bone graft substitute . it was found to have an excellent biocompatibility and to be safe to use in vivo ( 16 ) . its modular elasticity is similar to that of subchondral bone , yet its strength , fatigue properties , endurance limits , and initial stability against bone are all superior to natural bone grafts ( 17,18,19 ) . in fact , a recent study done in animal models showed that it had rapid tissue ingrowth and fixation strength , which allows faster return to full weight - bearing compared to procedures using fibular bone graft ( 20 ) . furthermore , another study which mechanically tested porous tantalum implants in a model mimicking a necrotic femoral head , demonstrated that tantalum implants reduced subchondral plate deflection and that its strength was 9.3 times greater than the maximum force it sustains when placed in the femoral head ( 21 ) . finally , local foreign body infection is a possible complication of orthopedic implants , and in this regard , schildhauer et al . have studied the adhesion of the two bacteria that are of most concern : staphylococcus aureus and staphyloccocus epidermis ( 22 ) . the former was found to adhere significantly less ( p<0.05 ) to pure tantalum compared to titanium alloy , polished stainless steel , and tantalum - coated stainless steel , and the latter bacteria adhered to pure tantalum to an extend similar to other materials used in orthopedics . all of these properties make tantalum implants good substitutes for fibular bone grafts in decompressing surgeries for osteonecrosis of the hip . theoretically , porous tantalum implants have the advantages of fibular grafts , providing core decompression and structural support , and , in addition , they represent a minimally invasive procedure with no donor - site morbidity . they thus have the theoretical potential of limiting the progression of the disease , which could delay , and maybe even prevent , the need for a hip replacement . this clinical study was performed to verify this theoretical advantage of the tantalum plug relative to core decompression alone or to fibular bone - grafting techniques . this study evaluates the early clinical outcomes of patients with advanced osteonecrotic femoral heads ( presenting with subchondral collapse or femoral head flattening ) treated with insertion of porous tantalum implants . we expected that this procedure would improve patients ' clinical symptoms , most often being pain and limitations in hip function , and , in turn , delay the need for revision with total hip arthroplasty , which was the endpoint of our study . this prospective study was conducted at the montreal general hospital , from april 2002 to february 2004 . experimental subjects were taken from patients referred to a single surgeon for treatment of steinberg stage iii and iv ( table 1 ) unilateral or bilateral femoral head osteonecrosis . only patients with non - traumatic etiologies for the disease were considered for participation in the study . exclusion criteria also included patients who were actively being treated with corticosteroids , had previous surgery to the affected hip , or were unwilling to have surgery at time of clinical presentation . patients were offered the tantalum implant procedure when they were unwilling to have treatment with free vascularized fibular graft or total hip arthroplasty . 19 patients with 22 osteonecrotic hips treated with tantalum implants were initially entered in the study and signed an informed consent form prior to enrollment . four patients were removed from the study as they were unavailable for follow - up at one year or later . one patient sustained trauma , more precisely a fall from her own height , resulting in a periprosthetic fracture one month postoperatively . this patient was not included in data analysis , but was rather included in the results as a complication . thus , functional outcomes of 14 patients with 17 osteonecrotic hips were used for analysis . the average age of the patients was 42 years old ( range 19 to 66 ) . all patients underwent the same operative procedure through a minimally invasive lateral approach ( 23 cm skin incision ) . it consisted of inserting a guide pin from the lateral femoral cortex into the femoral head and using a core reamer over this guide pin to create a 10-mm diameter bone channel . a porous tantalum plug ( zimmer trabecular metal technology , trabecular metal osteonecrosis intervention implant system , warsaw , indiana ; see figure 1 ) , was then inserted in this bony channel . this implant is fully made of pure porous tantalum , with an interconnected porosity of 7580% . it has a cylindrical shape of 10 mm in diameter , and comes in lengths of 70 to 130 mm , available in 5 mm increments . the implant is threaded on a 25 mm length at one end , where the diameter is 14 mm , and a hemispherical tip at the other , for support of the subchondral plate ( see figure 2 ) . bilateral procedures were performed in the same operative period , whether they were both tantalum implants or one tantalum implant and one free vascularized fibular graft , except for one patient who had a tantalum implant inserted in each hip at 3-month interval . postoperative care consisted of prophylactic intravenous antibiotic ( cefazolin 12 g iv q8h twice ) and anticoagulation therapy ( low molecular weight heparin 5000 iu sc qd until weight bearing ) . patients were instructed to be non - weight - bearing for 3 weeks , to partial weight - bear for the next 3 weeks , and to weight bear as tolerated thereafter . the primary outcome of this study was functional improvement , which was assessed with the harris hip score . this 15-question scoring tool for rating hip function was formulated and published in 1969 by wh harris , for evaluation of traumatic arthritis of the hip , and is now the scoring tool the most commonly used worldwide for assessment of hip function in general ( 23 ) . it consists of a point scale of a maximum of 100 points subdivided into 4 subscales : pain ( 44 points ) , function ( 47 points ) , range of motion ( 5 points ) , absence of deformity ( 4 points ) . a total harris hip score below 70 points is considered a poor result , 70 to 80 fair , 80 to 90 good , and 90 to 100 excellent ( 24 ) . sderman and malchau performed a validity and reliability test for the harris hip score ( 24 ) . they found that test and retest reliability between two examinations by physicians had correlation coefficients of 0.94 , and concluded that this scoring system had high content and construct validity . this score was obtained for each subject at their pre- and post - operative visits . because functional improvement after orthopedic surgeries usually improve mostly throughout the first year following the procedure and plateaus thereafter , postoperative scores obtained at 12 months or later were used as data points for analysis . when more than one follow - up with harris hip score recording had been done at one year post - operatively or later , the best score was taken , which was always the latest one . paired t - tests were used to compare pre - operative and postoperative harris hip scores among all patients , as well as within subgroups of patients who eventually failed and those who did not . failure , defined as being referred for or undergoing a total hip arthroplasty was the end point of this study . survival rate was calculated with the kaplan - meier method and refers to patients ' hips which did not progress to the point of requiring further surgical treatment . these analyses were performed with ssps manager ( version 11.5 ; ssps inc , chicago , illinois ) . paired t - test analysis was done to compare pre - operative to post - operative harris hip scores of patients ' hips that had not failed at 12 months post - operatively ( refer to table 3 ) . 2 patients with unilateral treatment were removed for analysis of hip function improvement since no pre - operative scores had been obtained . of the 12 hips of 10 patients remaining , 8 hips ( 75% ) in 7 patients improved their harris hip scores , the mean improvement was of a magnitude of only 3.8 points . standard deviations for the mean postoperative score and score improvement were very large , which reflects the discrepancy in individual postoperative values . when looking closely at these , it is noticed that they were very low in patients whose hips eventually failed , whereas they were greatly increased in patients whose tantalum implants succeeded , preventing the need for joint replacement surgery before the end of the study . mean harris hip score improvement was thus calculated separately for failed and non - failed tantalum implant procedures : a 21.7-point increase was obtained for patients who did well , compared with a mean decrease of 14.0 points for patients whose implants failed . this excludes three patients in whom three hips failed prior to the 12-month mark , and whose pre - operative harris hip scores were particularly low ( average 27.6 points ) . the average time of final follow - up and recording of the 14 harris hip scores used for analysis was 23.2 months ( range 12 to 48 ) . this excludes three patients , one of which had bilateral involvement , in whom one operated hip failed prior to the 12-month mark , more precisely at 7 , 8 and 10 months post - tantalum insertion , as well as one patient who sustained mild trauma to her single operated hip ( fall from own height ) resulting in a periprosthetic fracture ( see figure 3 ) . 6 additional hips in 4 patients , including all 3 patients with bilateral implant intervention including one whose contralateral hip had failed earlier , had undergone total hip arthroplasty before the final time of follow - up . therefore , 10 out of 18 ( 55.6% ) tantalum implant procedures failed within the study period . the mean time for failure , excluding the patient with a periprosthetic hip fracture , was 11.7 months ( sd=3.7 , range 7 to 20 months ) , and the mean age at surgery of the patients who failed was 50.1 years old ( sd=12.1 , range 29 to 66 ) , compared to a mean age of 36.8 years old ( sd=12.2 , range 19 to 55 ) for the patients whose tantalum implant did not fail . paired t - test analysis was done to compare pre - operative to post - operative harris hip scores of patients ' hips that had not failed at 12 months post - operatively ( refer to table 3 ) . 2 patients with unilateral treatment were removed for analysis of hip function improvement since no pre - operative scores had been obtained . of the 12 hips of 10 patients remaining , 8 hips ( 75% ) in 7 patients improved their harris hip scores , the mean improvement was of a magnitude of only 3.8 points . standard deviations for the mean postoperative score and score improvement were very large , which reflects the discrepancy in individual postoperative values . when looking closely at these , it is noticed that they were very low in patients whose hips eventually failed , whereas they were greatly increased in patients whose tantalum implants succeeded , preventing the need for joint replacement surgery before the end of the study . mean harris hip score improvement was thus calculated separately for failed and non - failed tantalum implant procedures : a 21.7-point increase was obtained for patients who did well , compared with a mean decrease of 14.0 points for patients whose implants failed . this excludes three patients in whom three hips failed prior to the 12-month mark , and whose pre - operative harris hip scores were particularly low ( average 27.6 points ) . the average time of final follow - up and recording of the 14 harris hip scores used for analysis was 23.2 months ( range 12 to 48 ) . this excludes three patients , one of which had bilateral involvement , in whom one operated hip failed prior to the 12-month mark , more precisely at 7 , 8 and 10 months post - tantalum insertion , as well as one patient who sustained mild trauma to her single operated hip ( fall from own height ) resulting in a periprosthetic fracture ( see figure 3 ) . 6 additional hips in 4 patients , including all 3 patients with bilateral implant intervention including one whose contralateral hip had failed earlier , had undergone total hip arthroplasty before the final time of follow - up . therefore , 10 out of 18 ( 55.6% ) tantalum implant procedures failed within the study period . the mean time for failure , excluding the patient with a periprosthetic hip fracture , was 11.7 months ( sd=3.7 , range 7 to 20 months ) , and the mean age at surgery of the patients who failed was 50.1 years old ( sd=12.1 , range 29 to 66 ) , compared to a mean age of 36.8 years old ( sd=12.2 , range 19 to 55 ) for the patients whose tantalum implant did not fail . osteonecrosis of the femoral head is a debilitating disease that requires treatment . since the late 1960s , several studies have evaluated effectiveness of potential techniques to treat this condition , such as core decompression , vascularized and nonvascularized fibular bone grafts , and angular or rotational osteotomies . performed a meta - analysis to look at the these studies , which were almost all performed on precollapse ( steinberg stage i or ii ) osteonecrotic femoral heads and thus their results can not be compared to ours ( 3 ) . furthermore , the conclusion of the meta - analysis was that early diagnosis and intervention prior to collapse of the femoral head , thus in earlier stages than in our patient population , is key to a successful outcome of joint - preserving procedures . however , 3 of the studies they looked at evaluated steinberg stage iv osteonecrotic hips treated with vascularized fibular bone grafts ; they showed clinical success rates of 52 , 48 and 71% at mean follow - up times of 12 months or more ( 25 , 26 , 27 ) . concluded in their meta - analysis that for femoral heads that have already collapsed , such as in our patients ' hips , the results of joint - preserving procedures are less satisfactory than the results of total hip arthroplasty ( 4 ) . in the present study , the success rate , defined as not requiring further hip treatment after core decompression tantalum implant insertion , was 77.8% at twelve months postoperatively . the overall success rate at final time of follow - up ( mean of 23.2 months ) was 44.5% . failures ( 10 hips , 55.6% ) occurred at a mean time of 11.7 months . this patient was included in the failure rate , as further surgical hip treatment was done , but was not included in the mean failure time , as this failure was due primarily to trauma , and thus does not reflect the time of failure of the tantalum implant per say . patients who did not require further treatment within the follow - up time improved their harris hip scores by 21.7 points , and patients who eventually underwent arthroplastic treatment decreased their score by 14 points , on average . the mean age at tantalum implant insertion in patients who failed was 50.1 years old , compared to 36.8 in patients who did well . the average preoperative harris hip score of patients who failed was 44.3 , compared with 59.5 for patients who did well . this suggests that age at surgery and preoperative hip function have prognostic implications for the porous tantalum implant insertion : the younger , less symptomatic , and less debilitated patients had the most favorable outcomes . our patient population is not large enough to make an association between outcome and etiology or uni / bilateralism of the disease process . our statistical findings are also limited in power because of the small number of subjects . the follow - ups , and thus postoperative score recording , were not done at the same time interval with respect to the surgery , making the results not as reproducible and precise as they could have been . tsao et al performed the only other published study to date evaluating the clinical outcome of porous tantalum implants in osteonecrotic human hips ( 28 ) . the mean harris hip scores of hips improved by 26 and 9 points in patients with stage iii and iv osteonecrotic hips respectively . one ( 14% ) stage iii and three ( 25% ) stage iv were revised , which is similar to our failure rate of 22.2% at one year . their success rate for all stage ii disease , which represented the bulk of their experimental data , was 85.3% at twelve months . they concluded that treatment of early stage osteonecrosis of the femoral head with core decompression and a porous tantalum implant show encouraging success rates , especially in association with early stage disease . have also recently done a study , with a publication in press , assessing clinical and radiographic outcomes of osteonecrotic hips treated with core decompression and porous tantalum implant ( 28 ) . they evaluated 60 hips : 1 steinberg stage i , 49 stage ii , and 8 stage iii . this is higher than ours , but it is likely due to the fact that most of their hips had stage ii osteonecrosis , compared to a majority of stage ivs in our study . overall , 3 of their 8 hips with stage iii disease were converted , representing a success rate of only 62.5% , which is more similar to our results . they concluded that treatment of early stage osteonecrosis of the femoral head with core decompression and a porous tantalum implant show encouraging success rates , especially in patients with early stage disease . in conclusion , core decompression with porous tantalum implant insertion provides a minimally invasive surgical treatment option to treat advanced osteonecrotic hips , with clinical outcomes and success rates comparable to other commonly used surgical procedures . it has the advantage of providing structural support without having associated donor - site morbidity . it seems however that this treatment modality is more successful in younger patients with more functional and less symptomatic hips . this is fortunate as it is for younger patients that the only definitive treatment so far , total hip replacement , is least appealing , as they are likely to outlive a hip prosthesis , thus requiring one or more revisions . in further studies , it would be useful to perform larger studies , perhaps at a multicenter level , to clearly elucidate the association between pre - operative stage and etiology of the disease , as well as patients ' age with success rate . this would enable us to make clear recommendations for choosing the best treatment modality for the individual patient .

purpose of the study : osteonecrosis of the hip mostly affects young individuals and often progresses to a debilitating disease . several treatment modalities exist , but none are completely satisfactory . this study evaluates the clinical outcome of patients treated with core decompression and insertion of a porous tantalum implant in the femoral head . this procedure is similar to commonly performed procedures , but has the additional advantages of providing structural support to the necrotic femoral head while having no donor - site morbidity . methods : we evaluated 15 patients with 18 osteonecrotic hips with steinberg stage iii ( 3 hips ) and iv ( 15 hips ) disease . the mean age of the patients was 42 years - old ( eldest 66 ) , and the mean time for follow - up was 23 months . the outcome measure was hip function , evaluated with the harris hip score , and the end point was total hip arthroplasty , or referral for this procedure . results : the success rate at twelve months postoperatively was 77.8% , and the overall success rate was 44.5% . failures occurred at a mean time of 11.7 months , and one complication , a periprosthetic fracture , occurred 4 months postoperatively . on average , patients who did well improved their harris hip scores by 21.7 points , and patients who eventually required arthroplasty decreased their scores by 14 points . conlusions : core decompression with porous tantalum implants showed encouraging success rates and early clinical results in patients with advanced stage osteonecrosis , but further larger scale studies are required to identify the population best suited for this procedure .

This is the third phase of NASA's efforts to get private space companies to take over the job of the now-retired space shuttle. The companies will share more than $1.1 billion. Two of the ships are capsules like in the Apollo era and the third is closer in design to the space shuttle. Once the spaceships are built, NASA plans to hire the private companies to taxi astronauts into space within five years. Until they are ready, NASA is paying Russia about $63 million per astronaut to do the job. In a statement, NASA Administrator Charles Bolden said the move "will help keep us on track to tend the outsourcing of human spaceflight." NASA hopes that by having private firms ferry astronauts into low Earth orbit, it can focus on larger long-term goals, like sending crews to a nearby asteroid and eventually Mars. The private companies can also make money in tourism and other non-NASA business. The three companies are the Boeing Co, Space Exploration Technologies, called SpaceX, and Sierra Nevada Corp. They are quite different companies. Boeing is one of the oldest and largest space companies with a long history of building and launching rockets and working for NASA, going back to the Mercury days. SpaceX is a relatively new company started by Elon Musk, who helped create PayPal and runs the electric car company Tesla Motors. Sierra Nevada has been in the space business for 25 years but mostly on a much smaller scale than Boeing. NASA's commercial crew development program started with seven companies. The other companies that were not chosen can still build private rocketships and NASA still has the option to hire them to ferry astronauts at a later date, NASA spokesman Trent Perrotto said. Boeing is slated to get the most money, $460 million for its seven-person CST-100 capsule. It would launch on an Atlas rocket, with the first test flight 2016. The company won't say how much it would charge NASA per seat, but it will be "significantly lower" than the Russian price, said John Mulholland, Boeing vice president. He said Boeing's long experience in working with NASA on human flight gives it a "leg up" on its competitors. SpaceX is already in the lead in the private space race. The company earlier this year used their Falcon rocket to launch their Dragon capsule into orbit. It docked with the space station and successfully delivered cargo. NASA plans to give the company $440 million. The capsule holds seven people and will have its first test launch with people in 2015, said spokeswoman Kirstin Brost Grantham. The company will charge NASA about $20 million per seat, she said. Sierra Nevada's mini-shuttle crew vehicle called Dream Chaser carries seven people and could be flown without a pilot. NASA would give them $212.5 million. The ship is based on an old NASA test ship design but has not flown as much as SpaceX's Dragon. "It may appear as though we are behind but in many ways we are more mature," said Sierra Nevada space chief Mark Sirangelo. Like Boeing's Mulholland, he said his firm will charge NASA less than the Russians, but will not give a specific price. ||||| * Boeing, SpaceX get lion's share * Sierra Nevada also selected * NASA wants ships ready in five years By Irene and Klotz PASADENA, Calif., Aug 3 (Reuters) - PASADENA, Calif. Aug 3 (Reuters) - NASA will pay more than $1 billion over the next 21 months to three companies to develop commercial spaceships capable of flying astronauts to the International Space Station, the agency said Friday. The lion's share of the $1.1 billion allotted for the next phase of NASA's so-called “"Commercial Crew" program will be split between Boeing and Space Exploration Technologies, a privately held firm run by Internet entrepreneur Elon Musk. Boeing will receive $460 million to continue developing its CST-100 capsule, which is intended to fly aboard a United Launch Alliance Atlas 5 rocket. ULA is a partnership of Boeing and Lockheed Martin. Space Exploration Technologies, or SpaceX, was awarded $440 million to upgrade its Dragon cargo capsule, which flies on the firm's Falcon 9 rocket, to carry people. In May, a Dragon capsule became the first privately owned spacecraft to reach the station, a $100 billion outpost that flies 240 miles (386 kilometres) above Earth. The test flight was part of a related NASA program to hire commercial companies to fly cargo to the station. Privately held Sierra Nevada Corp received a partial award of $212.5 million for work on its Dream Chaser, a winged vehicle that resembles a miniature space shuttle which also launches on an Atlas 5 rocket. All three firms are prior recipients of NASA space taxi development work. The new awards will more than triple NASA's investments in commercial crew programs, which so far total $365 million. Unlike previous NASA development programs, costs are shared between the government and its selected partners. "“The companies also are bringing money to the table. This is a way of allowing the United States to lead in the development of new space systems that are human-capability and then taking those systems for commercial purposes, as well as for NASA purposes in the future," program manager Ed Mango said. Since the space shuttles were retired last year, NASA is dependent on partners Russia, Europe and Japan to reach the station. Russia will remain the sole entity capable of flying crew until U.S. companies develop systems, which NASA hopes will be within five years. Shut out of the competition was Alliant Techsystems which hoped to parlay an ongoing unfunded NASA partnership agreement into a paying contract. Amazon.com founder Jeff Bezos's startup Blue Origin, which won $25.7 million during two predecessor programs, did not bid for the integrated design contracts awarded Friday. Three other firms - Space Operations, American Aerospace and Space Design - submitted proposals but were eliminated for not meeting requirements, NASA's associate administrator for space operations Bill Gerstenmaier said during a conference call with reporters. ||||| Computerworld - NASA announced Friday morning that it's on track to once again launch astronauts into space from U.S. soil within five years. As part of its strategy to launch astronaut-carrying spacecraft again, NASA has inked deals valued at more than $900 million with three U.S.-based commercial companies -- Sierra Nevada, SpaceX and Boeing -- to design and develop next-generation spacecraft technologies. The companies will build spacecraft for both government and commercial use. NASA will have the option to work with any or all of the companies and use their spacecraft to send astronauts into space or low Earth orbit, according to Stephanie Covey, a NASA spokesperson. "Today, we are announcing another critical step toward launching our astronauts from U.S. soil on space systems built by American companies," NASA Administrator Charles Bolden said in a statement. "We have selected three companies that will help keep us on track to end the outsourcing of human spaceflight and create high-paying jobs in Florida and elsewhere across the country." NASA retired its own fleet of space shuttles in the summer of 2011. NASA in May entered a new chapter of space flight when a craft built by Space Exploration Technologies Corp. (SpaceX) carried about 1,200 pounds of supplies, including student-designed experiments, food and clothing to the International Space Station. Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, or subscribe to Sharon's RSS feed . Her e-mail address is sgaudin@computerworld.com. Read more about Emerging Technologies in Computerworld's Emerging Technologies Topic Center.

– NASA is gearing up to again launch humans into space ... within five years. The agency retired its fleet of shuttles last summer, and this morning it announced a deal worth about $1 billion with three American companies to design and construct the next generation of rocket ships to take off from US soil, reports ComputerWorld. The three companies are Sierra Nevada, SpaceX, and Boeing, and the space vehicles they engineer will be flown for the government and for commercial use. (AP has more details on them here.) "Today, we are announcing another critical step toward launching our astronauts from US soil on space systems built by American companies," NASA chief Charles Bolden said in a statement. The move "will help keep us on track to end the outsourcing of human spaceflight and create high-paying jobs in Florida and elsewhere across the country." In the meantime, US astronauts will continue to hitch rides with Russian crafts, notes Reuters.

99 m. burkardt , advances nucl . phys . * 23 * , 1 ( 1996 ) . w. a.bardeen et al . , phys . d * 21 * , 1037 ( 1980 ) . m. burkardt and b. klindworth , submitted to prd , hep - ph/9601289 . m. burkardt , elfe meeting 1995 , hep - ph/9510264 . m. burkardt , lf - workshop , zakopane , aug 1994 , hep - ph/9410219 . p. a. griffin , lf - workshop , zakopane , aug 1994 , hep - ph/9410243 . b. grossmann et al . , _ int . j. mod . phys . _ * a6 * , 2649 ( 1991 ) . b. vande sande and s. dalley , hep - ph/9602291 . m. burkardt , nucl . * b373 * , 613 ( 1992 ) .

numerical results for the ( rest - frame ) @xmath0 potential in light - front quantized @xmath1 on a @xmath2 lattice are presented . both in the longitudinal as well as the @xmath2 spatial directions one obtains linear confinement . the confinement mechanism in light - front qcd depends on the orientation of the external charges : for longitudinally ( with respect to the boost direction in the infinite momentum frame ) separated quarks , confinement arises from the instantaneous interaction piece in the hamiltonian while for @xmath2 separated quarks , the confinement mechanism is similar to the one in hamiltonian lattice qcd . nevertheless , already a very simple ansatz for the effective link - field potential yields an almost rotationally symmetric @xmath0 potential . the momentum carried by the glue strongly depends on the orientation ( `` polarization '' ) of the @xmath0 pair . # 1#2#3#4#1 * # 2 * , # 3 ( # 4 ) light - front ( lf ) quantization is the most physical approach to calculating parton distributions on the basis of qcd @xcite . in the transverse lattice formulation of qcd @xcite , one keeps the time direction and one spatial direction continuous and discretizes the transverse spatial directions . the space time geometry is thus an array of @xmath3 dimensional sheets ( fig . [ fig : perpl ] ) . one the one hand , this provide both uv and iv cutoffs in the transverse directions and on the other hand one can still perform lf quantization since the longitudinal directions are continuous . furthermore , in the compact formulation , it is straightforward to implement gauss law as a constraint on the states avoiding troublesome divergences for @xmath4 , which plague many other formulations of lf qcd . another advantage of the transverse lattice is that confinement is manifest in the limit of large @xmath2 lattice spacing @xmath5 . the mechanism differs for the longitudinal and the @xmath2 directions : if one separates a @xmath0 pair longitudinally then , since @xmath5 is large , the fields in different sheets couple only weakly and the quarks interact only with fields in the same sheet , i.e. effectively the theory reduces to @xmath3 dimensional qcd , where confinement is known to be linear . in contrast , when one separates the @xmath0 pair transversely , gauge invariance demands that they are connected by a chain of ( gluon ) link fields . for large @xmath5 , where there are only little fluctuations , this implies that the energy of such a configuration is given by the energy for creating one link quantum times the number of link quanta , i.e. linear confinement also in the @xmath2 direction . since the confinement mechanisms are very different for these two cases , one might ask whether a rotationally invariant @xmath0 potential results in the continuum limit . in fact , in the limit of large @xmath5 one finds in @xmath6 dimensions @xcite : @xmath7 where @xmath8 is the string tension , which is clearly not rotationally invariant . in order to investigate this issue , i used dlcq and a lanzcos algorithm to calculate the rest frame @xmath0 potential from the lf hamiltonian for @xmath1 on a @xmath2 lattice . the procedure for computing the rest frame potential in this formalism follows ref . @xcite . the light - front hamiltonian for compact qcd on a transverse lattice has been introduced by bardeen @xcite . for pure glue qcd in 2 + 1 dimensions one finds @xmath9 : + v_{eff}(u ) , \label{eq : pminus}\ ] ] where @xmath10 .45 cm ( 15,9.3)(-7,5.5 ) ( 1.5,8.5)(0,1)1.7 ( 1.,11.1)(0,0)(discrete ) ( 1.,12.0)(0,0)@xmath2 space ( 1.5,12.6)(0,1)1.6 ( 2.,8.)(3,-1)1.2 ( 4.5,6.9)(0,0)long . space ( 4.5,6.2)(0,0)(continuous ) ( 7.1,6.3)(3,-1)1.8 ( 10.4,5.8)(3,1)1.8 ( 14.5,6.2)(0,0)(continuous ) ( 14.5,6.9)(0,0)time ( 15.8,7.6)(3,1)1.8 and @xmath11 are the link fields , which are quantized matrix fields and satisfy the usual commutation relations . ideally , one would like to work with @xmath12 , but in practice this is very complicated @xcite and it is advantageous to work with an unconstrained complex matrix field and instead add an effective constraint term @xmath13 to the light - front hamiltonian . in the case of @xmath14 , in the classical limit , @xmath13 can be taken of the form @xmath15 : + c_4 \sum_n\mbox{tr}:\left [ u^\dagger_nu_nu^\dagger_nu_n\right ] : , \label{eq : constr}\ ] ] where @xmath16 and @xmath17 , which provides an effective potential which is minimized for @xmath18 . in the @xmath19 limit , the difference between @xmath20 and @xmath21 is irrelevant and eq.([eq : constr ] ) is thus suitable for enforcing the @xmath21 constraint in the classical limit . one might be tempted to try a similar ansatz for the lf quantized case there are several reasons why a different form for the effective potential might be desirable . first , if one would still attempt to work with an effective potential of the above form then physical states would necessarily look extremely complicated , which has to do with the fact that the above ansatz for the effective potential corresponds to working close to the continuum limit . thus even if the ansatz in eq.([eq : constr ] ) would work in principle , it would most likely not be very practical . furthermore , since a `` mexican hat '' potential corresponds to a situation where one is working with the _ false _ vacuum , it is questionable whether a physical situation where a particle runs at the bottom of a mexican hat can be described at all by a lf hamiltonian using degrees of freedom expanded around the origin . for these two reasons , it makes more sense not to consider @xmath11 as the _ bare _ link field , but instead think of it as some kind of _ blocked _ or _ smeared _ variable . the blocking has several consequences . first , the @xmath21 constraint gets relaxed which reflects itself in the fact that the effective potential is no longer just a narrow valley @xcite . secondly , using smeared variables , it might be easier to cover large physical distances with only few degrees of freedom . the price one has to pay for these advantages is that the effective potential gets more complex and in general more terms are necessary than shown in eq.([eq : constr ] ) . in ref . @xcite an attempt has been made to fit the effective potential to the glueball spectrum by making an ansatz which includes all operators up to dimension four . since this work is a first study of the rest - frame @xmath0 potential and , as we will discuss below , the @xmath0 potential turns out to be rather insensitive to terms of dimension greater than two in @xmath13 , we will instead only consider a much simpler ansatz in the following and keep only the quadratic term @xmath22 an approximation , where one allows at most one link field quantum per link , was used . within this approximation , one obtains only a first order phase transition at the critical point , i.e. the lattice spacing always remains finite in physical units . the calculations were done at the critical point , where @xmath23 ( @xmath24 ) with ( without ) fock space truncation . the resulting @xmath0 potential is shown in fig . [ fig1 ] as a function of @xmath25 . 1.cm ( 1.5,1)(1.35,7.3 ) ( 3.,6.)(0,0)(a ) ( 15,6)(-7,1.3 ) ( 3.,6.)(0,0)(b ) one free dimensionless parameter was adjusted in the calculation to get equal string tensions in the longitudinal and transverse directions ( note that this parameter does not affect the numerical calculation but is only relevant for scale setting ) . for large @xmath5 , @xmath26 fills the area between the dotted lines . the symbols are numerical results at the critical point for various directions . the small residual anisotropy is probably due to the use of an oversimplified effective potential . note that while qed and qcd are equivalent as long as one restricts oneself to only one quantum per link ( fig . [ fig1]a ) , this is no longer the case for the calculations without such a restriction ( fig . [ fig1]b ) . intuitively , one would expect a much stronger violation of rotational symmetry than in fig . [ fig1 ] . the reason this did not happen is probably the following : typically , ground states of lf hamiltonians are dominated by the lowest fock component . for the string connecting a @xmath0 pair , this implies that the wavefunction is dominated by components with only one quantum per link where higher order terms in the effective potential do not matter . we are currently investigating excited states of the @xmath0 string , which correspond to hybrid stated of quarkonium @xcite . in these excited states , higher order terms in the effective potential do matter and we expect to obtain information about the connection between the form of the effective potential and rotational symmetry . 1.cm ( 15,8.5)(-1,1.5 ) another physical observable for the @xmath0 states is the momentum carried by the glue ( fig . [ fig : xglue ] ) . one finds a strong anisotropy in the sense that the gluons ( link fields ) carry much more momentum when the @xmath0 pair is separated transversely than when it is separated longitudinally ( at the same physical distance , i.e. even though the same amount of energy is stored in the gluon field in both cases ) . such a result is physical and is familiar from qed @xcite . it can be most easily understood from the point - of - view of an infinite momentum boost : if the electric field lines before the boost are @xmath2 to the boost directions , the field after the boost will look almost like a transverse electromagnetic wave and carries a large ( pointing ) momentum . this is not the case when the electric field is parallel to the boost direction . the anisotropy effect is more pronounced in qcd than in qed because the ( rest frame ) electric field is squeezed into flux tubes . this effect might have measurable consequences in the decays of polarized hybrid states and shows that the difference between confinement mechanisms in lf - qcd for longitudinal and @xmath2 directions has physical consequences .

the kelvin - helmholtz ( kh ) instability is of much interest in the investigation of variety of the astrophysical phenomena such as interaction between jets or outflows and the ambient medium ( e.g. , watson et al . 2007 ; birk & wiechen 2002 ; rosen et al . 1999 ; downes & ray 1998 ; hardee & stone 1997 ; bodo et al . 1995 ; ) . this instability , the simplest example of shear flow instability , is a well - known phenomenon in fluid mechanics and astrophysics ( e.g.chandrasekhar 1961 ) . despite the very existence of the ions , neutrals and charged dust particles in jets or outflows ( markwick - kemper , green & peeters 2005 ; weinberger & armsdorfer 2004 ; gueth , bachiller & tafalla 2003 ; shepherd 2001 ) , the kh instability in these systems has been studied mostly in one fluid approximation just for simplicity . dusty outflows are observed in some of the starburst galaxies ( e.g. , alton , davies & bianchi 1999 ) . however , a two - fluid treatment of kh instability , taking account of the different motions of ions and neutrals and of the magnetic field , has been investigated by some authors as well ( e.g. , birk et al . 2000 ; watson et al . 2004 ; chhajlani & vyas 1991 ; chhajlani & vyas 1990 ) . birk et al . ( 2000 ) studied the kh instability by taking into account the full incompressible dynamics of both the neutral and the ionized gas components with applications to multi - phase galactic outflow winds . in another similar study , watson et al . ( 2004 ) investigated the kh instability in the linear , partially ionized regime to determine its possible effect on entrainment in massive bipolar outflows . they showed that for much of the relevant parameter space , neutral and ions are sufficiently decoupled that the neutrals are unstable while ions are held in place by the magnetic field . shadmehri & downes ( 2007 ) extended this analysis to a _ layer _ of ions and neutrals with finite thickness . they showed that perturbations with wavelength comparable to layer s thickness are significantly affected by the thickness of the layer . birk & wiechen ( 2002 ) focused on unstable shear flows in partially ionized dense dusty plasma . they considered the dust and neutral gas components so that dust and neutral collisions is the dominant momentum transfer mechanism and dust component can interact with magnetic field lines , although dust charge fluctuations are negligible . they showed long wavelength modes can be stabilized by dust and neutral gas collisional momentum transfer . however , their analysis focused on numerical solution and multifluid numerical simulations of the problem of shear flow in weakly ionized , magnetized dusty plasmas , and did not concentrate on solving the dispersion relation for this type of flow . in this paper , we will obtain the dispersion relation of kh instability in a multifluid system . recently , wiechen ( 2006 ) studied the kh instability by doing multifluid numerical simulations in partially ionized , dusty plasmas for different masses and charges of dust . he showed a stabilizing effect for more massive dust grains with no dependence on the charge polarity of the dust . in this paper , we study kh instability in a multifluid system _ analytically_. in particular , we apply our results to magnetized dusty outflows . in the next section , the basic equations and assumptions which are based on pandey & vladimirov ( 2007 ) are presented . we develop analytic estimates of the relevant time scales of the kh modes . in section 3 , properties of the unstable growing modes are studied . our basic equations and the main assumptions are similar to pandey & vladimirov ( 2007 ) . we take account of the different bulk velocities and densities of the neutral , electrons , ions and charged dust particles on both sides of the kh interface . the continuity equation is @xmath0 where @xmath1 and @xmath2 are the velocity of the various plasma components and the neutrals , respectively . the momentum equations are @xmath3 @xmath4 note that velocities @xmath2 are written in the neutral frame and @xmath5 is the electric field in the neutral frame . @xmath6 stands for electrons ( @xmath7 ) , ions ( @xmath8 ) and dust ( @xmath9 ) , where @xmath10 is the number of charge on the grain . the other physical variables have their usual meanings . also , the collision frequencies is ( draine et al . 1983 ) @xmath11 where @xmath12 is the rate coefficient for the momentum transfer by the collision of the @xmath13 particle with the neutrals : @xmath14 @xmath15 and for small grains , we have @xmath16 , but for grains ranging between a few angstrom to a few microns ( nakano & umebayashi 1986 ) @xmath17 @xmath18 where @xmath19 is the grain radius . in our calculation , for the ion mass and mean neutral mass we adopt @xmath20 and @xmath21 , where @xmath22 is the proton mass . defining the mass density of the bulk fluid and the bulk velocity as @xmath23 and @xmath24 , equations ( [ eq : conj ] ) , ( [ eq : momj ] ) and ( [ eq : momn ] ) give the continuity and the momentum equations for the bulk fluid as @xmath25 @xmath26 the next simplifying assumption is that electrons and ions are assumed well coupled to the magnetic field which implies @xmath27 , where @xmath28 is the ratio of cyclotron @xmath29 to the collision frequencies . based on this assumption and using quasi - neutrality condition , we have ( pandey & vladimirov 2007 ; ciolek & mouschovias 1993 ) @xmath30 where @xmath31\beta_{d}^{2}.\label{eq : theta}\ ] ] thus , the induction equation can be written as ( pandey & vladimirov 2007 ) @xmath32\label{eq : induc}\ ] ] equations ( [ eq : main1 ] ) , ( [ eq : main2 ] ) and ( [ eq : induc ] ) along with the equation @xmath33 are our basic equations for kelvin - helmholtz instability in a partially ionized medium . however , we assume incompressibility for the analytical calculations . for doing linear analysis , the unperturbed properties of the system are important . we suppose that the streaming takes place in the @xmath34direction with velocity @xmath35 , @xmath36 where @xmath37 is constant . the magnetic field is assumed parallel to the interface ; that is , @xmath38 . finally , all unperturbed physical quantities are assumed constant in each medium . now , we can linearize the basic equations . we perturb the physical variables as @xmath39.\ ] ] thus , @xmath40 @xmath41 @xmath42 @xmath43 @xmath44 @xmath45 @xmath46 @xmath47 where @xmath48 and @xmath49 is the modified dust - cyclotron frequency . now , we can simplify the above differential equations . by multiplying equation ( [ eq : xmom ] ) by @xmath50 and equation ( [ eq : ymom ] ) by @xmath51 and then adding the resulting equations , we obtain @xmath52 where @xmath53 . this equation gives @xmath54 in terms of the other variables and the parameters . by substituting @xmath54 into equation ( [ eq : zmom ] ) , we obtain @xmath55 where @xmath56 . on the other hand , using equations ( [ eq : xmom ] ) and ( [ eq : ymom ] ) we have @xmath57 also , using equation ( [ eq : bx ] ) and ( [ eq : by ] ) we obtain @xmath58 @xmath59 so , from equations ( [ eq : help2 ] ) and ( [ eq : help3 ] ) we have @xmath60 @xmath61 substituting this equation into equation ( [ eq : bz ] ) gives @xmath62 equations ( [ eq : main1 ] ) and ( [ eq : main2 ] ) are our main equation for kh analysis . however , we can simply them into one differential equation for @xmath63 , @xmath64 where @xmath65^{2},\label{eq : q}\ ] ] and @xmath66 is alfven speed . the general solution of equation ( [ eq : final ] ) is a linear combination of @xmath67 and @xmath68 . thus , we can write the solutions of equation ( [ eq : final ] ) appropriate to the two regions as @xmath69 where @xmath70 , @xmath71 , @xmath72 and @xmath73 are the constants of integration yet to be obtained from the boundary conditions appropriate to our system . note that @xmath74 and @xmath75 are given by equation ( [ eq : q ] ) , and are assumed to have a positive real part so as to render the perturbations bounded at infinity . we have @xmath76^{2}\},\ ] ] @xmath77^{2}\},\ ] ] and @xmath78 and @xmath79 . the boundary conditions to be satisfied at the interface @xmath80 are the standard conditions which have been used by many authors ( hunter & whitaker 1989 ; roychoudhury & lovelace 1986 ; mehta & bhatia 1988 ; chhajlani & vyas 1990 ; chhajlani & vyas 1991 ) . we are using the continuity of normal and tangential components of the magnetic field , the vertical displacement of the interface and the total pressure as the boundary conditions . after doing mathematical manipulations , we obtain @xmath81 @xmath82a_{2}=\frac{x+1}{x-1}[1- { \mathcal m}^2 ( x-1)^{2}]a_{4},\ ] ] @xmath83 @xmath84 @xmath85.\ ] ] for a non - trivial solution of the above algebraic equations , the determinant of the coefficients should vanish . we get the following equation @xmath86}k,\label{eq : diss}\ ] ] where @xmath87 and @xmath88/[1-m^{2}(x+1)^{2}]$ ] . equation ( [ eq : diss ] ) is the general dispersion relation . however , it would be extremely unwieldy to solve it its present form . after substituting the values of @xmath74 and @xmath75 and doing long algebraic mathematical manipulations , we can transform equation ( [ eq : diss ] ) into a polynomial form , i.e. @xmath89 @xmath90 where @xmath91 and the coefficients @xmath92 ... @xmath93 are presented in the appendix . we note that not all roots of the equation ( [ eq : dissal ] ) are acceptable . all roots are inserted into our fundamental dispersion relation ( [ eq : diss ] ) to determine which are the valid solutions . we accept only those solutions which have negative imaginary part _ and _ give us positive values for the real parts of @xmath74 and @xmath75 . now , we carry out a parameter study of the roots of equation ( [ eq : dissal ] ) as functions of the input parameters . although this dispersion relation is applicable to a wide range of astrophysical systems , we restrict our analysis to dusty outflows with small grains in order to illustrate the effect of charged dust particles on the growth rate of the unstable modes . we take the molecular hydrogen density to be @xmath94 @xmath95 and the ratio of ionized to neutral mass density is @xmath96 . also , the ratio of dust to neutral density is assumed to be 0.01 . the bulk density of a dust particle is assumed @xmath97 gr @xmath98 . also , the relative velocity @xmath99 is assumed to be 20 km s@xmath100 . we note that the electrical charge of the dust particles appears only through the modified dust - cyclotron frequency @xmath101 . but in our final dispersion relation , this parameter @xmath102 appears and so , the polarity of the electrical charge of the dust particle is not important . since we fix the densities and the velocity for the flow , when the magnetic field strength increases the mach number decreases . another important input parameter is modified dust - cyclotron frequency @xmath101 which is calculated based on the other input parameters . figure [ fig : f1 ] shows growth rates of the fastest unstable growing mode versus wavelength of the perturbations for different level of the magnetic strength and various sizes of dust particles . here , the electrical charge of dust particles is assumed to be @xmath103 . top plot of figure [ fig : f1 ] shows the dispersion relation for weak magnetic field , but the bottom plot is for magnetic field with stronger strength . we noticed as the strength of the magnetic field increases , the time - scale of the growing modes becomes independent of the variations of mass of the dust particles . in top plot of this figure , solid curves are corresponding to magnetic strength @xmath104 @xmath105 g , but dashed lines are for @xmath106 @xmath105 g . each curve is labeled by the size of the dust particles . when the size ( i.e. , mass ) of the dust particles increases , the time - scale of the growing modes increases too . in other words , mass of the dust particles has a stabilizing effect on the growing modes . in bottom plot of figure [ fig : f1 ] , the dispersion relation is shown for stronger magnetic field strengths , i.e. @xmath107 , 80 and 100 @xmath105 g . however , the plots are insensitive to the mass of small dust particles . we see as the magnetic field increases , the growth rate of the unstable modes at a particular wavelength of the perturbation increases . it means that the magnetic field has a destabilizing effect on the unstable modes . figure [ fig : f2 ] shows the dispersion relation for the magnetic strength @xmath104 @xmath105 g and dust particles with radius @xmath108 angstrom , but changing the electrical charge of the grains . as the charge of the grain increases , the growing time - scale of the unstable modes increases . we can understand the latter result as follows . from the form of our dispersion relation it is clear that the only variable which changes as we vary the grain radius , @xmath19 , is @xmath109 through the modified dust cyclotron frequency , @xmath101 . using relations ( [ eq : nu ] ) , ( [ eq : dn ] ) , the definition of @xmath101 and recalling that the mass of a dust grain is proportional to @xmath110 we can see that as @xmath19 increases @xmath101 decreases . physically this means that larger grains are less well coupled to the magnetic field , since the dust grains can only respond to variations of the magnetic field with frequency less than @xmath101 . as figure [ fig : f1 ] shows , the magnetic field destabilizes the flow . hence it is no surprise that as the dust component of the flow becomes less coupled to the field the flow becomes more stable . a similar argument explains the results in fig [ fig : f2 ] . according to the definition of the modified dust cyclotron frequency , we have @xmath111 . since equation ( [ eq : theta ] ) shows that @xmath112 , we can conclude that @xmath113 . thus , for increasing values of @xmath114 the dust cyclotron frequency @xmath101 decreases which implies less magnetic coupling and greater growth times . interestingly , numerical simulations ( e.g. wiechen 2006 ) and laboratory experiments ( e.g. luo , angelo & merlino 2001 ) have also shown that the kelvin - helmholtz mode is significantly stabilized with increasing mass of the dust . we studied the kh instability in a multifluid system analytically . our results show that a higher mass of the dust particles has a stabilizing effect on the growing kh modes . but when the strength of the magnetic field increases , the time - scale of the growing modes gradually are becoming independent of dust size or mass . also , the dynamics of unstable modes are independent from the charge polarity of the dust . considering the wavelength of the perturbations and the time scale of the growing modes , we may conclude that some of structures which are seen in dusty outflows ( e.g. , weinberger & armsdorfer 2004 ; gueth , bachiller & tafalla 2003 ; shepherd 2001 ) are produced by the kh instability . we are grateful to the referee , g. e. ciolek , for suggestions and comments to improve the paper . the research of m. s. was funded under the programme for research in third level institutions ( prtli ) administered by the irish higher education authority under the national development plan and with partial support from the european regional development fund . alton p. b. , davies j. i. , bianchi s. , 1999 , a&a , 343 , 51 birk g. t. , wiechen h. , 2002 , physics plasmas , 9 , 964 birk g. t. , wiechen h. , lesch h. , kronberg p. p. , 2000 , a&a , 353 , 108 bodo g. , massaglia s. , rossi p. , rosner r. , malagoli a. , ferrari a. , 1995 , a&a , 303 , 281 chandrasekhar s. , 1961 , hydrodynamics and hydromagnetic stability ( oxford : oxford univ . press ) chhajlani r. k. , vyas m. k. , 1991 , ap&ss , 176 , 69 chhajlani r. k. , vyas m. k. , 1990 , ap&ss , 173 , 109 ciolek g. e. , mouschovias t. ch . , 1993 , apj , 418 , 774 downes t. p. , ray t. p. , a&a , 1998 , 331 , 1130 gueth f. , bachiller r. , tafalla m. , a&a , 2003 , 401 , l5 hardee p. e. , stone j. m. , 1997 , apj , 483 , 121 hunter j. h. , whitaker r. w. , 1989 , apjs , 71 , 777 luo q. z. , angelo n. d. , merlino r. l. , 2001 , physics plasmas , 8 , 31 markwick - kemper f. , green j. d. , peeters e. , 2005 , 628 , l119 mehta v. , bhatia p. k. , 1988 , ap&ss , 141 , 151 pandey b. p. , vladimirov s. v. , 2007 , apj , 664 , 942 rosen a. , hardee p. e. , clarke d. a. , johnson a. , 1999 , apj , 510 , 136 roychoudhury s. , lovelace r. v. e. , 1986 , apj , 302 , 188 shepherd d. s. , apj , 2001 , 546 , 345 shadmehri m. , downes t. p. , astrophysics & space science , 2007 , in press watson c. , churchwell e. , zweibel e. g. , crutcher r. m. , 2007 , apj , 657 , 318 watson c. , zweibel e. g. , heitsch f. , churchwell e. , 2004 , apj , 608 , 274 weinberger r. , armsdorfer b. , 2004 , a&a , 416 , l27 wiechen h. , 2006 , physics plasmas , 13 , 062104 the coefficients of equation ( [ eq : dissal ] ) are

we investigate the linear theory of kelvin - helmholtz instability at the interface between a partially ionized dusty outflow and the ambient material analytically . we model the interaction as a multifluid system in a planar geometry . the unstable modes are independent from the charge polarity of the dust particles . although our results show a stabilizing effect for charged dust particles , the growth time scale of the growing modes gradually becomes independent of the mass or charge of the dust particles when the magnetic field strength increases . we show that growth time scale decreases with increasing the magnetic field . also , as the mass of the dust particles increases , the growth time scale of the unstable mode increases . 235 mm instabilities - ism : general - ism : jets and outflows

-John F. Keenan, U.S. District Court judge for the Southern District of New York "Climate change is a fact of life, as is not contested by Defendants. But the serious problems caused thereby are not for the judiciary to ameliorate. Global warming and solutions thereto must be addressed by the two other branches of government." The city had argued the five companies were responsible for more than 11 percent of all industrial carbon dioxide and methane emissions since the Industrial Revolution. Attorneys for New York also alleged the companies downplayed the risks of burning fossil fuels while privately acknowledging the threat of global warming for decades. But on Thursday, John F. Keenan, U.S. District Court judge for the Southern District of New York, granted the defendants' request to dismiss the complaint. In his ruling, Keenan agreed with the argument made by attorneys for the companies that the case should be tossed because the city's claims arise under federal common law, which displace the city's state law claims. The judge also ruled that the Clean Air Act displaced the city's claims. He said courts have previously determined that interstate emissions from burning fossil fuels is a "federal concern" that has been "delegated to the Executive Branch as they require a uniform, national solution." "Climate change is a fact of life, as is not contested by Defendants. But the serious problems caused thereby are not for the judiciary to ameliorate. Global warming and solutions thereto must be addressed by the two other branches of government," Keenan wrote. Last month, a federal judge dismissed climate change cases against oil companies brought by Oakland and San Francisco based on similar grounds. Exxon Mobil also reiterated that view following the ruling. "We have said all along that addressing the risks of climate change is a serious global challenge that should be addressed by policymakers and not by the courts," Scott Silvestri, a media relations manager for Exxon said in a statement. In its own statement, ConocoPhillips said, "We are pleased that a second federal court judge has agreed that climate change is a global issue that requires global policies and solutions addressed through the U.S. legislative and executive branches, not the courts." Lastly, Keenan concluded that the city's claims raise concerns about separation of powers and foreign policy because New York is suing two foreign companies — BP and Shell — and seeking to hold all five firms liable for worldwide greenhouse gas emissions. "Thus, to the extent that the City seeks to hold Defendants liable for damages stemming from foreign greenhouse gas emissions, the City’s claims are barred by the presumption against extraterritoriality and the need for judicial caution in the face of 'serious foreign policy consequences,'" Keenan said, citing a 2018 District Court ruling in Virginia. ||||| BALTIMORE (AP) — Baltimore on Friday become the latest U.S. city to try and hold the world's biggest oil companies financially responsible for global warming, asserting it faces massive costs to effectively protect its residents, businesses and infrastructure from the escalating impacts of climate change. The litigation by Baltimore, wrapped around a cove of the Chesapeake Bay, comes as skeptical judges elsewhere have been throwing out headline-generating complaints brought by other cities that sought to force big oil companies to pay for climate change adaptation. On Thursday, a U.S. judge rejected New York City's lawsuit targeting oil companies, saying the issue must be addressed by Congress and the executive branch. Last month, another federal judge tossed litigation brought by San Francisco and neighboring Oakland that accused "Big Oil" of long knowing that fossil fuels posed serious risks to the environment, but still promoting them as environmentally responsible. Baltimore, with some 60 miles of waterfront and a major port, is making an identical argument while seeking unspecified damages. But it has chosen to file its climate-change litigation in Baltimore Circuit Court, not a federal court. Its effort targets 26 oil and gas companies for damages associated with sea level rise and other effects of climate change. Companies listed in Baltimore's complaint include ExxonMobil, Chevron and Shell. When asked for comment about Baltimore's lawsuit, Exxon spokesman Scott Silvestri said that addressing "the risks of climate change" is "a serious global challenge that should be addressed by policymakers and not by the courts." Baltimore Solicitor Andre Davis and Mayor Catherine Pugh issued forceful statements saying the mid-Atlantic city's people and businesses should not have to pay for climate change impacts they assert are the responsibility of Big Oil. "For 50 years, these companies have known their products would cause rising seas and the other climate change-related problems facing Baltimore today," Davis said. "They could have warned us. They could have taken steps to minimize or avoid the damage. In fact, they had a responsibility to do both, but they didn't, and that's why we are taking them to court." Pugh described the city of 615,000 inhabitants as being on the "front lines of climate change" and accused the fossil fuel industry of spending billions to "deceive, delay, distract and attack" those who've tried to hold them accountable. The Center for Climate Integrity advocacy group applauded Baltimore's effort, describing it as "the next in a growing wave of climate liability lawsuits." "The people of Baltimore deserve their day in court," said Richard Wiles, executive director of the Washington-based organization. __ Follow McFadden on Twitter: https://twitter.com/dmcfadd ||||| NEW YORK (AP) — New York City's effort to hold oil companies responsible for global warming was rejected by a judge Thursday who said placing blame for the issue is not the judiciary's responsibility. U.S. District Judge John F. Keenan said global warming is a problem best left to the other two branches of government. "The immense and complicated problem of global warming requires a comprehensive solution that weighs the global benefits of fossil fuel use with the gravity of the impending harms," Keenan wrote in his decision. Keenan said the lawsuit implicates countless foreign governments and their laws and policies. "To litigate such an action for injuries from foreign greenhouse gas emissions in federal court would severely infringe upon the foreign-policy decisions that are squarely within the purview of the political branches of the U.S. government," he said. The city earlier this year sued five of the world's biggest oil companies, blaming them for global warming. It sought unspecified damages from BP, Chevron, ConocoPhillips, Exxon Mobil and Royal Dutch Shell. The decision echoed the findings last month of a federal judge in San Francisco who rejected a similar lawsuit on the same grounds after city officials in San Francisco and Oakland had sued the same oil companies. The city said it would appeal. Seth Stein, a spokesman for Mayor Bill de Blasio, said the Democratic mayor "believes big polluters must be held accountable for their contributions to climate change and the damage it will cause New York City." Theodore Boutrous, who argued on behalf of the oil companies at a recent hearing before Keenan, said the judge "got it exactly right." "Trying to resolve a complex, global policy issue like climate change through litigation is 'illogical,' and would intrude on the powers of Congress and the Executive Branch to address these issues as part of the democratic process," he said in a statement. "The court relied on bedrock Supreme Court precedent to reject these baseless claims." Ken Kimmell, president of the Union of Concerned Scientists, said in a release that the lawsuit was not focused on solving global warming but instead was meant to compensate the city for tens of billions of dollars it has caused and will cause in the future. ___ Associated Press Writer David Koenig contributed to this report ||||| FILE - In this July 18, 2018, file photo, lawyers and youth plaintiffs lineup behind a banner after a hearing before Federal District Court Judge Ann Aiken between lawyers for the Trump Administration... (Associated Press) FILE - In this July 18, 2018, file photo, lawyers and youth plaintiffs lineup behind a banner after a hearing before Federal District Court Judge Ann Aiken between lawyers for the Trump Administration... (Associated Press) PORTLAND, Ore. (AP) — A lawsuit filed by young activists who say the government is failing to protect them from climate change is still alive. In San Francisco on Friday, the 9th U.S. Circuit Court of Appeals rejected the government's second request for an order directing a lower court to dismiss the case. The lawsuit brought by 21 children and young adults asserts the government has long known that carbon pollution causes climate change but has failed to curb greenhouse gas emissions. They are seeking various environmental remedies. The judges said the government's first request failed to meet the high bar for having the case dismissed at this stage. A trial is set to begin Oct. 29 in Eugene, Oregon.

– A lawsuit filed by young activists who say the government is failing to protect them from climate change is still alive, the AP reports. In San Francisco on Friday, the 9th US Circuit Court of Appeals rejected the government's second request for an order directing a lower court to dismiss the case. The lawsuit brought by 21 children and young adults asserts the government has long known that carbon pollution causes climate change but has failed to curb greenhouse gas emissions. They are seeking various environmental remedies. The judges said the government's first request failed to meet the high bar for having the case dismissed at this stage. A trial is set to begin Oct. 29 in Eugene, Oregon. In related news, New York City's effort to hold oil companies responsible for global warming was rejected by a judge Thursday who said placing blame for the issue is not the judiciary's responsibility, per the AP. US District Judge John F. Keenan said global warming is a problem best left to the other two branches of government—Congress and the executive, notes CNBC. "The immense and complicated problem of global warming requires a comprehensive solution that weighs the global benefits of fossil fuel use with the gravity of the impending harms," Keenan writes in his decision. Meanwhile, Baltimore on Friday become the latest US city to try and hold the world's biggest oil companies financially responsible for global warming, per the AP. The city filed a lawsuit in Baltimore Circuit Court for unspecified damages against 26 oil and gas companies.

organ transplantation has become an established therapeutic option for most types of end - stage organ failure , but transplantations are limited by shortage of donated organs . live organ donation offers a valuable opportunity for transplantation , but cadaveric organ donation extends the possibility for reducing the gap between patients needs and the organ supply . in libya , , kidney and liver transplantations were performed only from living , related donors , which restricted the transplantation activities and prolonged patient suffering and waiting time . transplantation of organs from human cadavers has steadily increased in many countries in the past decades , including many middle eastern countries , in which the culture resembles that in libyan society [ 68 ] . various factors have been associated with unwillingness to donate organs after death , including age , gender , level of education , knowledge regarding organ donation , and awareness of organ shortage [ 911 ] . reports from turkey , mexico , brazil , usa , and spain determined some criteria in favor of deceased organ donation . it included younger age , female gender , and higher level of education [ 914 ] . other research related the disinclination to religious reservations about transplanting organs from dead people [ 1518 ] . this study aims to explore the state of willingness to participate in organ donation after death and to identify the major reasons for refusal . the results could help in developing strategies for establishing a deceased organ donation programs in libya and in directing educational organizers to better approaches for building a favorable public opinion . it was conducted from april to july 2008 in four libyan cities after obtaining approval from the organ transplantation research committee . a cluster sample of 1652 participants was recruited ( 58% males and 42% females ; from approximately 370 to 550 persons from each city ) . they were randomly selected from 10 public facilities ( universities , schools , companies , banks and post offices ) . it included the names ( codes ) of all employees/ students/ teachers and/or workers in that facility . cities included in the study were tripoli ( 600 persons ) , benghazi ( 600 persons ) , sabha ( 400 persons ) and gharyan ( 400 persons ) . the researchers visited the public facilities and orally got consent from those who were included in the sample to participate in the study by fulfilling a self administered anonymous questionnaire sheet . it included information about respondents ' age , gender , educational level , occupation and marital status . the central question was about willingness of the respondent to donate his or her organs after death and the reasons for refusal for those who were unwilling to donate . the validity of the questionnaire 's content was judged by a team of psychologists , sociologists and an organ transplant surgeon . the reliability of the questionnaire , as determined by the test - retest method , was 0.83 . a pilot study was conducted on february 2008 on 73 randomly selected individuals from banks in tripoli to assess the phrasing of the questionnaire and the time required to complete it . the finalized arabic questionnaire ( table 1 ) consists of seven items . the first part included information about age , sex , educational level , occupation , and marital status . the second part consisted of the question assessing the willingness of the respondents to be organ donors after death , and provided a choice of six different reasons for refusal , plus a space where they could mention any other reasons . the questionnaire ( translated from arabic ; the arabic version is available upon request ) the question format ( yes i agree , no i do n't agree , and i have not decided ) was used for the item exploring the willingness of the responders to be an organ donors . the time needed to fill out the questionnaire form was not supposed to exceed four minutes based on the pilot study . the chi - square test was used to determine the statistical significance of association between categorical variables . the response rate , after exclusion of uncompleted questionnaires and those filled by respondents who were less than 20 years of age , was 82.6% . of the 1652 participants , 491 ( 29.7% ) agreed with donating their organs after death , 993 ( 60.1% ) expressed refusal , and 10.2% were undecided . willingness to donate organs after death was significantly ( p<0.05 ) more frequent among males ( 33.7% ) than females ( 24.2% ) . younger participants were more accepting of donating organs after death than older participants : 38.1% of those aged 2029 years agreed to donate organs after death compared to only 3.2% of those who were 50 years or older ( p<0.05 ) . on the other hand , strong unwillingness to donate organs posthumously was observed among the older age groups ; the refusal rate was 70.5% and 80.4% in the 4049 and the > 50 year categories , respectively . the most willing were holders of postgraduate degrees ( 57.4% ) while the least willing were those with less than a high school education ( 12.8% ) ( table 2 ) ; the difference between these groups was significant ( p<0.05 ) . moreover , students were more willing to donate their organs after death than the other categories ( p<0.05 ) . conversely , rejection of this type of organ donation was more frequent among the unemployed , the retired , and housewives ( 96.5% ) . another statistically significant relation ( p<0.05 ) was observed with marital status , where 34.3% of single respondent agreed to donate organs as compared to 24.7% of married respondents . lack of adequate knowledge about the importance of deceased organ donation and uncertainty about its religious standing were the most predominant responses ( 43.8% and 39.5% , respectively ) . other reasons included ethical concerns about retrieving organs from dead body ( 37.9% ) , preferring to be buried intact ( 28% ) , and uneasiness about the idea of cadaver manipulation ( 33% ) . noteworthy , more than one quarter of the respondents had never thought about organ donation , and 16.8% of those who refused to donate gave no reason . in libya , organ transplantation activities are seriously limited because it depends exclusively on living donors . the strategies of the libyan organ transplantation program to initiate deceased organ transplantation activities included advocacy , which helped in obtaining legal approval of organ donation and transplantation besides organizing and publishing meetings with the religious leaders in the country to facilitate the passage of a religious ruling official proclamation of religious acceptance . it also included launching many educational campaigns through the media to familiarize people with the concept of deceased organ donation and motivate them to participate . these efforts can benefit from an assessment of the reasons behind current resistance to cadaveric donation , and the knowledge gained would help decision makers to plan more effective strategies to address the obstacles . we found that less than one third of the surveyed individuals were willing to donate their organs after death . this result is far lower than the results reported by other studies , which ranged between 4675% [ 9 , 10 , 1921 ] . the present low willingness rate is similar to that published by bilgel et al . in turkey during in 1991 , in which only 33.7% of the surveyed individuals were willing to donate their organs after death ( . however , in turkey the willingness rate rose to 57% after 12 years , which indicates that concepts and attitudes of people toward this issue change over time as a result of well planned educational programs . although it was observed that willingness to donate organs does not guarantee that the individual will obtain a donor card [ 10 , 23 ] , the level of willingness we observed indicates the presence of a substantial source of potential donors in the local community . we also analyzed the relationship between different demographic variables and willingness to donate organs after death . we found that male respondents exhibited significantly stronger willingness than females to donate their organs after death . this finding is contrary to other observations in usa , mexico , and spain [ 10 , 13 , 14 ] . our results point to the need to analyze why libyan females have relatively more negative attitudes than males and indicate that they should be encouraged to discuss this topic . younger people ( 2029 years ) exhibited more than ten - fold higher agreement rate than those who were 50 years of age or more . younger people generally have more favorable attitudes and willingness to donate organs after death [ 9 , 13 , 14 , 2426 ] in agreement with other studies [ 9 , 13 , 20 , 24 ] , we found that more educated people were more supportive of deceased organ donation . other significant finding of this study was the relationship between marital status and willingness to donate organs after death . we found that the most prominent reason given for rejecting organ transplantation from cadavers was insufficient knowledge about the implication of deceased organs . also , more than quarter of the refusing respondents had simply never thought about organ donation . in addition to that , many individuals stated that they knew nothing about the process of deceased organ donation and its regulation , including where and how to obtain a donor card . lack of knowledge about deceased organ donation had already been reported as the most important reason for refusing this type of donation in australia , hong kong and spain [ 13 , 16 , 27 ] . in qatar certainly , lack of information about deceased organ donation questions the validity of the educational practices undertaken by the libyan organ transplantation program and the role of major media outlets . it draws attention to the need to evaluate the impact of information resources in libyan society . the short age of the libyan transplantation program , the weak educational approach , and insufficient media converge about the project could be some reasons for poor population knowledge . the second most frequent reason for refusal in this study was religious concern emanating from the inadequacy or ineffectiveness of an islamic fatwa about the permissibility of cadaveric donation in the community . most preceding studies , which focused on attitudes and willingness to donate cadaveric organs , showed that refusal because of religious concerns were frequent observation and that a clear official religious position in support of cadaveric donation is important for the spread of positive attitudes among muslims [ 15 , 2634 ] . repulsion of the idea of cadaver manipulation and ethical concerns about deceased organ donation , in addition to concerns about intact body at burial were very well recognized reasons for unwillingness in the previous studies as well as the present study [ 13 , 3537 ] . about one third of refusing individuals had reported such worries . in mexico , zepeda - romero et al found out that bodily mutilation was the main reason for people 's negative stand on cadaveric donation . in conclusion , lack of proper knowledge , religious doubts and concerns about body manipulation act as barriers against deceased organ donation progress . this activity might be augmented by participation of religious leaders to tackle the debate about the issue experienced by the public .

introductionorgan transplantation in libya depends exclusively on donations from live relatives . this limitation increases mortality and prolongs the patients suffering and waiting time.objectivesthe aims of this study were to explore willingness to donate organs after death and to identify the reasons for refusal.methodsa population - based crosssectional study was conducted from april to july 2008 on a cluster sample of 1652 persons ( 58% males and 42% females ) . the questionnaire included demographic information and mainly enquired about willingness to donate organs after death and the reasons for refusal when applicable.resultsabout one - third ( 29.7% ) of participants were in favor of donating their organs after death , 60.1% refused and 10.2% were undecided . willingness was significantly associated with being male , younger age , having a college or graduate degree , and being single ( p < 0.05 for all ) . lack of adequate knowledge about the importance of deceased organ donation and uncertainty about its religious implications were the most predominant reasons for refusal ( 43.8% and 39.5% , respectively ) . other reasons included ethical concerns about retrieving organs from dead bodies ( 37.9% ) , preference for being buried intact ( 28% ) , and uneasiness about the idea of cadaver manipulation ( 33%).conclusionthere were a considerable resistance to deceased organ donation , especially among females , those of older age , married people , and those with a low education level . the barriers to cadaveric donations were lack of adequate knowledge , unease about body manipulation , and concerns about religious implications . public educational campaigns should be coordinated with religious leadership .

the materials , protocols , and experimental procedures have been described in our previous study , except that an optical tweezers instrument with higher spatial resolution was used for this study . the pause times from all ribosomes under the same experimental condition were pooled together to calculate the average translation rate by a boot - strapping method : i ) half of all pause times are randomly selected , histogrammed , and fitted to a single exponential ; ii ) this procedure is repeated for > 1000 times ; iii ) the average translation rate and its error are determined as the average and the standard deviation/ 2 of the fitted rate constants from all the repeats . , the effect of force on the free energy of the open junction , gf , is calculated from the worm - like chain model for rna single strands as gf=0fxnt(f)df , where xnt(f ) is the total extension of the single - strands released per translocation step under force f.

the ribosome translates the genetic information encoded in messenger rna into protein . folded structures in the coding region of an mrna represent a kinetic barrier that slows the peptide elongation rate , as the ribosome must disrupt structures it encounters in the mrna at its entry site to enable translocation to the next codon . such structures are exploited by the cell to create diverse strategies for translation regulation , such as programmed frameshifting1,2 , protein expression levels3,4 , ribosome localization5 , and cotranslational protein folding6 . although strand separation activity is inherent to the ribosome , requiring no exogenous helicases7 , its mechanism is still unknown . here , using a single - molecule optical tweezers assay on mrna hairpins , we find that the translation rate of identical codons at the decoding center is greatly influenced by the gc content of folded structures at the mrna entry site . furthermore , force applied to the ends of the hairpin to favor its unfolding significantly speeds translation . quantitative analysis of the force dependence of its helicase activity reveals that the ribosome , unlike previously studied helicases , uses two distinct active mechanisms to unwind mrna structure : ( i ) it destabilizes the helical junction at the mrna entry site by biasing its thermal fluctuations toward the open state , increasing the probability for the ribosome to translocate unhindered ; and ( ii ) it also mechanically pulls apart the mrna single - strands of the closed junction during the conformational changes that accompany ribosome translocation . our results establish a quantitative mechanical basis for understanding the mechanism of regulation of the elongation rate of translation by structured mrnas .

since the introduction of laparoscopic hernia repair by schultz in 1990 , surgeons have compared this new technique to the traditional repairs of mcvay , bassini , shouldice and lichtenstein . the endoscopic preperitoneal herniorrhaphy , which is based on the established open preperitoneal techniques of stoppa , nyhus , wantz and others , is becoming increasingly accepted as the best laparoscopic technique for repair of groin hernias . bilateral inguinal hernia repair is rarely performed during traditional open herniorrhaphy . on the other hand , one widely accepted indication for the performance of endoscopic preperitoneal herniorrhaphy is the presence of bilateral hernias . to our knowledge , no prior studies have compared the recovery following unilateral and bilateral endoscopic preperitoneal hernia repairs . presented herein is a study comparing intraoperative and postoperative data for patients undergoing endoscopic herniorrhaphy for either unilateral or bilateral hernias . from july 15 , 1994 to august 16 , 1996 , a total of 250 patients underwent repair of 373 hernias by a single surgeon ( als ) in a teaching setting . one hundred twenty - seven patients underwent unilateral hernia repair ( uh ) , while 123 patients underwent bilateral hernia repair ( bh ) . the male : female ratio was 114:13 for uh and 121:2 for bh ( p>0.05 ) . mean age was 56 for uh ( range 18 - 89 ) and 53 for bh ( range 1886 ) ( p > 0.05 ) . type of anesthesia used and the percentage of virgin and recurrent hernias were likewise similar for the two groups ( table 2 ) . ( note : all patients presenting with recurrent hernias had previously undergone open hernia repairs . ) postoperative patient survey . patients were asked to record responses to the following three criteria on the day of surgery as well as postoperative days 1 , 2 , 3 , 7 , 14 , and 28 . they were also asked to record the date of return to work and/or full normal activity , ( note : notations in parentheses are legends for figures 17 ) patient demographics . preoperative antibiotics prophylaxis consisted of a single dose of cefazolin ( 1 g ) or vancomycin ( 500 mg ) . the preperitoneal space was created with the use of a preperitoneal distension balloon ( pdb , origin medsystems , menlo park , ca ) and was maintained with co2 insufflation at a pressure of 12 mm mercury . for all hernia repairs , dissection was carried out to identify and/or expose cooper 's ligament , the inferior epigastric vessels , the internal ring , the spermatic cord and the iliofemoral vessels . a single sheet of polypropylene mesh was used to repair each hernia in this series ( size range of 3 x 5 to 4 x 6 inches ) . a keyhole incision was created superiolaterally in the mesh to allow the mesh to wrap around the cord , thus recreating the internal ring . the mesh was fixed to the anterior abdominal wall and cooper 's ligament using either the endoscopic multifire stapler ( ems , ethicon endo - surgery , cincinnati , oh ) or origin tacker ( origin medsystems , menlo park , ca ) . no mechanical fixation of the mesh was performed below the iliopubic tract except at cooper 's ligament . at the completion of the repair(s ) , 30 cc of 0.25% bupivacaine with epinephrine ( 1:100,000 ) were placed into the preperitoneal space for the purpose of postoperative analgesia . postoperative pain control was managed with oral acetaminophen with codeine ( tylenol # 3 ) in all patients . at the time of discharge , all patients were sent home with a postoperative questionnaire . they were asked to qualitate their level of pain as well as keep track of their level of activity and number of narcotic analgesic pills ingested . patients were asked to log these criteria on the day of surgery as well as postoperative days 1 , 2 , 3 , 7 , 14 and 28 . patients were also asked to record their return to work or , if retired or unemployed , when they were able to resume full " normal " activity ( table 1 ) . initially , patients were asked to mail these forms back to the surgeon 's office upon completion of the survey . with these response rates less than 100 percent , the forms were collected and discussed at the first postoperative visit ( at 2 - 3 weeks postop ) if the patients had returned to full activity . statistical methods included t - test , chi - square test and mann - whitney rank sum test . intraoperative data are summarized in table 3 although operative time was longer in the bilateral group ( 65 vs. 43 minutes ; p < 0.05 ) , iv fluid requirements were the same for both groups ( 1289 cc vs. 1292 cc ; p > 0.05 ) . all hernia repairs were successfully completed endoscopically , with no conversions to open technique required . postoperative surveys were collected through mail follow - up or at the time of the first postoperative visit . response rates for the two groups were similar ( 81/127 ( 64% ) for uh and 81/123 ( 66% ) for bh ; p > 0.05 ) . the legend for these figures is given in table 1 ( i.e. , p0 , p1, ... ,n0 , n1, ... ( note : legend for figure is in table 1 . ) postoperative data for endoscopic herniorrhaphy on postoperative day # 1 . ( note : legend for figure is in table 1 . ) postoperative data for endoscopic herniorrhaphy on postoperative day # 3 . ( note : legend for figure is in table 1 . ) postoperative data for endoscopic herniorrhaphy on postoperative day # 7 . ( note : legend for figure is in table 1 . ) postoperative data for endoscopic herniorrhaphy on postoperative day # 14 . ( note : legend for figure is in table 1 . ) postoperative data for endocopic herniorrhaphy on postoperative day # 28 . no significant differences for perception of pain , narcotic use or level of activity were noted on any of the days measured ( p > 0.05 for all comparisons on all days ) . the unilateral group returned to work / normal activity at 6.32 + /3.29 days and bilateral group returned to work / normal activity at 6.68 + / 4.13 days ( p>0.05 ) . one of the more established indications for the performance of endoscopic preperitoneal herniorrhaphy is the presence of bilateral hernias , yet no prior studies have compared postoperative recovery following unilateral and bilateral endoscopic herniorrhaphy . the majority of these studies have focused on transabdominal laparoscopic techniques . in order to evaluate the postoperative course of patients undergoing groin herniorrhaphy , a survey was designed . this survey assesses patient recovery based on a qualitative measure of pain , a quantitative record of narcotic use , and a record of day - to - day activity . this study shows for the first time that the recovery following endoscopic preperitoneal herniorrhaphy is the same for patients with unilateral and bilateral hernias . no differences existed for perception of pain , narcotics used , or level of activity on any of the days analyzed . the addition of a contralateral hernia repair during the performance of an endoscopic preperitoneal herniorrhaphy is well tolerated by patients . this is likely due to the small increase in operative time , as well as the minimal additional dissection needed to expose the inguinal anatomy on the second side . bilateral herniorrhaphy can be performed without the need for additional trocar placement or repeat balloon dissection of the preperitoneal space . the tension free onlay of a second piece of polypropylene mesh apparently adds little to the postoperative symptom complex . our experience demonstrates that bilateral endoscopic preperitoneal herniorrhaphy can be performed with the same expected patient recovery as unilateral repair .

introduction : the advantage of using minimally invasive techniques over open techniques in the repair of inguinal hernias remains unclear . one of the more established indications for the performance of minimally invasive ( e.g. endoscopic preperitoneal ) herniorrhaphy is the presence of bilateral hernias . however , no prior study has compared the recovery following unilateral and bilateral endoscopic preperitoneal hernia repairs.patients and methods : from july 15 , 1994 through august 16 , 1996 one primary surgeon performed 373 hernia repairs on 250 patients . unilateral herniorrhaphy ( uh ) was performed on 114 males and 13 females with an average age of 58 ( range 1889 ) . bilateral herniorrhaphy ( bh ) was performed on 121 males and 2 females with an average age of 53 ( range 18 86 ) ( p>0.05 ) . within the uh group there were 105 virgin hernias and 22 recurrent hernias . the bh group included 212 virgin hernias and 34 recurrent ( p>0.05).bilateral repairs took longer to perform than unilateral repairs ( 65 minutes vs. 45 minutes ) ( p<0.05 ) . at the time of discharge , all patients were given a postoperative survey and asked to record their level of pain , narcotic use and level of activity on the day of surgery and postoperative days 1 , 2 , 3 , 7 , 14 , and 28.results:no differences were found in pain perception , narcotic use or level of activity on any of the days measured between the two groups ( p>0.05 ) . in addition , both groups returned to work at a similar time ( uh : 6.32 + /3.29 days , bh : 6.68 + / 4.13 days ) ( p>0.05).conclusion : bilateral endoscopic preperitoneal herniorrhaphy can be performed with the same expected patient recovery as unilateral repairs .

porosities in dental casting alloy can alter physical and mechanical properties of the mental which inturn may lead to failure of crown and bridge , and also cast partial denture prosthesis . in our current economy , it is obligatory that dentists and technicians be cost conscious about the materials they use for fixed prosthesis . cast gold alloy is in use since a long time as restorative materials in dentistry . the alloy 's properties like resistance to tarnish and corrosion , hardness , strength , percentage elongation , castability , burnishability and capacity to take high polish have made it as an ideal restorative material . however , it has two main disadvantages : one is its highly distinguishable color and the other is high cost . the preferential use of the precious metal alloys like gold alloy has almost been eliminated by the elevated cost and resulted into subsequent demand for semiprecious and nonprecious base metal alloys in dental procedures . in 1930s , base metal alloys were introduced to dentistry by eardle rw and prange ch . the properties of this alloy satisfy with that of gold alloy with the additional advantage of its reduced specific gravity and low cost . due to this superiority over gold alloy , cobalt , chromium and nickel alloy and its allies have become immensely popular in the field of restorative dentistry . this popularity of these alloys can be gauged by the varieties of the alloys available in the market . it is a point of commercial concern that the present demand for the base metal alloys has resulted in a substantial increase in the price of these once insignificant alloys . due to nobility of the contents of the gold alloys , it has been possible to recast the material again and again without losing any of its required properties . however , the same can not be said about base metal alloys , due to lack of research work and literature available . invariably , the manufacturers of base metal alloys instruct to use the alloy only once . therefore , it will be of great advantage , both economically and environmentally , to recycle or to recast the alloy again and again with or without adding new alloy . very few references in dental literature are available regarding recasting of the base metal alloys . few have tested the properties of the alloy by casting the used material and others have tested by adding new material to the casted alloy . it will be of definite scientific advantage if the properties of the recast alloys are studied in detail and directions given to prosthodontist and laboratory technicians . therefore , this study has been undertaken to find out the porosities in the new alloy , different percentage combinations of new alloy and once casted alloy and recasted alloy . acrylic - wax mesh ( klett - o - flex , renfert , hilzingen , germany ) of dimensions 11 mm 11 mm with 100 square shaped spaces of 1 mm 1 mm and filament diameter of 0.3 mm was selected . chromium alloy ( g - soft , dentaurum , ispringen , germany , with a chemical composition ni 65% ; cr 27% ; mo 5% ; si 1.5% ; other elements c , mn , b less than 1% ) . for the first group of castings , totally new alloy was used , i.e. , 100% new alloy ; this group was designated as group a. the buttons of these castings from group a were separated from its sprue . these buttons were cut into different portions so as to mix it with new alloy by weight in proper proportions . in this study , the following groupings [ table 1 ] were made based on different combinations of new alloy and once casted alloy : different groups and its % combinations three samples from each group were selected randomly for the measurement of porosities . clear epoxy resin and formaldehyde were mixed in a ratio of 1:1 and poured into a standard mould over the samples and allowed to set . it was then further smoothened with grade 0 and finished with grade 000 emery paper . care was taken to produce uniform , scratch - free surface and to have a mirror finish . the disk was covered with a velvet polishing cloth which was kept moist with slurry of various gradations of aluminium oxide powder . embedded specimens were mounted on a metallurgical microscope ( invertoscope , labo , ambala , india ) for evaluation of porosities in the sprue and runner bar region . the porosity analysis was carried out by thorough scanning of sprue and runner bar under a magnification of 100. then , photographs were taken with slr camera ( pantex , tokyo , japan ) under 100 magnifications . so , a repeat porosity study was carried out under scanning electron microscope ( jeol , jsm t330 a ) . the embedded specimens were removed from the embedding of epoxy resin material as this material was not accepted by scanning electron microscope [ figure 1 ] . photograph showing scanning electron micorsope then , all the samples were scanned thoroughly in the region of runner bars and the sprue , under scanning electron microscope . for comparison between different samples from different groups , three particulars sites from each group were selected . those were two apex portions of two runner bars and the junction of two runner bars and the sprue . , porosities were seen in the one of the samples in group d [ figure 5d ] . every sample from group e exhibited porosities in one out of three sites . [ figures 6b , 6d ] occurrence of porosity in group a occurrence of porosity in group b occurrence of porosity in group c occurrence of porosity in group d occurrence of porosity in group e sprues and buttons remaining after casting were used again for casting with addition of lost copper . since 1930s , base metal alloys like cobalt chromium ( co cr ) and nickel chromium ( ni cr ) are in use as indirect restorative materials , as they were cost effective . in 1930s and 1940s , the cost of these base metal alloys was affordably low , so the sprues and buttons remaining after casting were discarded . however , at present , the cost of these base metal alloys has become very high . in spite of this , very few manufacturers advocate part addition of new alloy to the sprue and buttons for recasting . apart from the cost due to environmental factors and deprivation of the resources , these properties should remain constant not only during various laboratory procedures but also in the oral environment . therefore , it is very clear that recasting should not be done at the expense of the properties of the alloy . since 1962 , studies regarding recasting of base metal alloys have been conducted by various researchers , namely , harcourt , hesby , hong , nelson and presswood . mainly , they have studied properties of recast alloy , such as tensile strength , ultimate tensile strength , percentage elongation , modulus of elasticity , mean yield strength , microstructure and microhardness . however , as per the review of literature , there have been very few studies regarding the porosities in recasted nickel chromium alloy . therefore , this study was undertaken to study porosities in the nickel chromium alloy . so far , the study on properties of recast alloy has been done either by casting the same alloy again and again up to 13 generations or by studying the properties of the castings with the addition of new allow to the recasted alloy in various proportions . it is easy and scientific to compare the properties of the only new alloy , with various percentage combinations of new alloy and once casted alloy and with only recasted alloy . in this study , the following groups [ table 2 ] were made : perfect casting should be not only accurate but also free of porosities . presence of porosities reduces the strength of the casting.[14911 ] hence , it is one of the criteria to study the change in the properties of the recasted alloy . as mentioned earlier , as per review of literature , only nelson has studied the porosities in recasted nickel chromium alloy by using metallurgical microscope . in this study , embedded samples were mounted on a metallurgical microscope and photographs were obtained ; but as the photographs obtained were not of satisfactory quality , the study was reconducted by using scanning electron microscope . porosities are always studied at the thickest portion of the castings and in the area which is farthest away from the junction of the sprue and the patterns . as the mesh filaments were very thin , it was not an ideal region to study the porosities . hence , the farthest ends of the runner bar , i.e. , the apex of the runner bars , the junction of the two runner bars and the sprue , were subjected for microscopic studies . all the microscopic photographs of the specimens from group a [ figures 2a , 2b , 2c ] , group b [ figure 3a and 3b ] , group c [ figures 4a and 4b ] and group e [ figures 6a and 6c ] ( indicate the absence of porosities in all the specimens except in one belonging to group d [ figure 5d ] . it should be noted that even in group d , two samples did not show any porosities among the three samples observed . porosity free micrograph of apex of the runner bar ( group a ) porosity free micrograph of the junction of two runner bars and sprue ( group a ) porosity free micrograph of the apex of runner bar ( group a ) porosity free micrograph of the junction of two runner bars and the sprue ( group b ) porosity free micrograph of the apex of the runner bar ( group b ) porosity free micrograph of the runner bar ( group c ) porosity free micrograph of the apex of runner bar ( group c ) porosity free micrograph of the apex of runner bar ( group e ) porosity free micrograph of the junction of two runner bars and the sprue ( group e ) micrograph showing porosities ( white dots ) in the region just below the apex of runner bar ( grooup d ) porosity free micrograph of the apex of runner bar ( group d ) porosity free micrograph of the apex of the runner bar ( group d ) porosity free micrograph of the juction of two runner bars and the sprue ( group d ) in group e , all the three samples showed porosities at only one site in each sample , as shown in figure 6b and 6d one sample out of three samples showed porosity at the one apex of the runner bar [ figure 6b ] , and in other two samples , porosities were seen in the sprue region of the sample [ figure 6d ] . but it is to be noted that the micro - porosities were detected in small amounts . this finding is almost similar to the findings of nelson where microporosity was not readily apparent . but the occurrence of porosities in the sprue region is bound to take place and has been already proved . micrograph of the apex of the runner bar showing porosity in the center ( group e ) micrograph showing porosities ( white dots ) in the sprue region ( group e ) based on this study it can be advocated that recasted alloy can be used at least once again . as per the studies of harcourt , recasting can be done up to 13th generation without losing any properties of the alloy . it can also be advocated that completely cleaned and deoxidized casted alloy need not be added with new alloy in any proportion . this finding is of great significance in view of the cost involved and maintaining the level of available resources . chromium alloy.it is not necessary to add new alloy in any proportion to the once casted alloy to minimize porosities in the alloy.we have studied only till the second generation of the recasted alloy . it is suggested to recast the alloy for a number of generations and study its effect on the properties of the alloy . it is not necessary to add new alloy in any proportion to the once casted alloy to minimize porosities in the alloy . we have studied only till the second generation of the recasted alloy . it is suggested to recast the alloy for a number of generations and study its effect on the properties of the alloy .

statement of problem : as per the review of literature very few studies have been carried on recasting of dental casting alloy and in particlular its effect on occurrence of porosities.purpose of study : this study was designed to find out occurrence of porosities in new alloy and recasted alloy using a scanning electron microscope.materials and methods : different percentage combinations of new and once casted alloy were used to produce twenty five samples . castings obtained from new alloy were used as control group . all the samples were scanned under scanning electron mocroscope and photographs were taken from three specific sites for comparison.results:there is no significant difference in occurrence of porosities in casting obtained by using new alloy and recasted alloy.conclusion:with in the limitations of the study it is conducted that the prorosities will not be affected by recasting of neckel - chromium alloy.clinical implication : porosities in dental casting alloy can alter physical and mechanical properties of the mental which inturn may lead to failure of crown and bridge , and also cast partial denture prosthesis .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Muhammad Ali Commemorative Coin Act''. SEC. 2. FINDINGS. Congress finds that-- (1) Muhammad Ali was an Olympic gold medalist, 3-time World Heavyweight Champion boxer, and one of the most celebrated and well-known athletes in American history; (2) Muhammad Ali showed, beyond his impressive fighting prowess in the boxing ring, even greater courage and tenacity as an advocate outside the ring; (3) Muhammad Ali was a great philanthropist and a strong champion of peace, equality, and freedom; (4) Muhammad Ali remains an icon of freedom of conscience; (5) Muhammad Ali was a prominent African American of the Muslim faith, and was, and continues to be, a role model to the citizens of the United States of all races, ethnicities, and religions; (6) Muhammad Ali used his fame to advocate for humanitarian causes in audiences with world leaders ranging from religious leaders to heads of state; and (7) Muhammad Ali inspired people around the globe in displaying the same vibrant and larger-than-life character and dedication in spite of his physical ailments. SEC. 3. COIN SPECIFICATIONS. (a) Denominations.--The Secretary of the Treasury (hereafter in this Act referred to as the ``Secretary'') shall mint and issue the following coins in commemoration of Muhammad Ali: (1) $5 gold coins.--Not more than 100,000 $5 coins, which shall-- (A) weigh 8.359 grams; (B) have a diameter of 0.850 inches; and (C) contain 90 percent gold and 10 percent alloy. (2) $1 silver coins.--Not more than 350,000 $1 coins, which shall-- (A) weigh 26.73 grams; (B) have a diameter of 1.500 inches; and (C) contain not less than 90 percent silver. (b) Legal Tender.--The coins minted under this Act shall be legal tender, as provided in section 5103 of title 31, United States Code. (c) Numismatic Items.--For purposes of section 5134 and 5136 of title 31, United States Code, all coins minted under this Act shall be considered to be numismatic items. SEC. 4. DESIGN OF COINS. (a) Design Requirements.-- (1) In general.--The design of the coins minted under this Act shall be emblematic of the life and legacy of Muhammad Ali. (2) Design and inscriptions.--On each coin minted under this Act there shall be-- (A) a designation of the value of the coin; (B) an inscription of the year 2020; and (C) inscriptions of the words ``Liberty'', ``In God We Trust'', ``United States of America'', and ``E Pluribus Unum''. (b) Selection.--The design for the coins minted under this Act shall be-- (1) selected by the Secretary after consultation with the Muhammad Ali Center; and (2) reviewed by the Citizens Coinage Advisory Committee. SEC. 5. ISSUANCE OF COINS. (a) Quality of Coins.--Coins minted under this Act shall be issued in uncirculated and proof qualities. (b) Mint Facility.--Only 1 facility of the United States Mint may be used to strike any particular quality of the coins minted under this Act. (c) Period for Issuance.--The Secretary may issue coins minted under this Act only during the 1-year period beginning on January 1, 2020. SEC. 6. SALE OF COINS. (a) Sale Price.--The coins issued under this Act shall be sold by the Secretary at a price equal to the sum of-- (1) the face value of the coins; (2) the surcharge provided in section 7(a) with respect to such coins; and (3) the cost of designing and issuing the coins (including labor, materials, dies, use of machinery, overhead expenses, marketing, and shipping). (b) Bulk Sales.--The Secretary shall make bulk sales of the coins issued under this Act at a reasonable discount. (c) Prepaid Orders.-- (1) In general.--The Secretary shall accept prepaid orders for the coins minted under this Act before the issuance of such coins. (2) Discount.--Sale prices with respect to prepaid orders under paragraph (1) shall be at a reasonable discount. SEC. 7. SURCHARGES. (a) In General.--All sales of coins issued under this Act shall include a surcharge of-- (1) $35 per coin for the $5 coin; and (2) $10 per coin for the $1 coin. (b) Distribution.--Subject to section 5134(f)(1) of title 31, United States Code, all surcharges received by the Secretary from the sale of coins issued under this Act shall be promptly paid by the Secretary as follows: (1) Eighty percent of the surcharges shall be paid to the Muhammad Ali Center in Louisville, Kentucky, to ensure growth and innovation in museum programming to research, promote, and educate on the legacy of Muhammad Ali. (2) Ten percent of the surcharges shall be paid to the Muhammad Ali Institute for Peace and Justice at the University of Louisville to advance the work, study and practice of peacebuilding, social justice, and violence prevention through the development of innovative educational programs, training, service, and research. (3) Ten percent of the surcharges shall be paid to the Muhammad Ali Parkinson Center (MAPC) and Movement Disorder Clinic to continue serving as a resource for Parkinson's disease patients and their families through the provision of diagnosis, treatments, research, and education. (c) Audit.--The Comptroller General of the United States shall have the right to examine such books, records, documents, and other data of each of the organizations referred to in subsection (b) as may be related to the expenditures of amounts paid under that subsection. (d) Limitations.--Notwithstanding subsection (a), no surcharge may be included with respect to the issuance under this Act of any coin during a calendar year if, as of the time of such issuance, the issuance of such coin would result in the number of commemorative coin programs issued during such year to exceed the annual 2 commemorative coin program issuance limitation under section 5112(m)(1) of title 31, United States Code (as in effect on the date of the enactment of this Act). The Secretary of the Treasury may issue guidance to carry out this subsection.

Muhammad Ali Commemorative Coin Act This bill requires the Department of the Treasury to mint and issue commemorative coins that emblemize the life and legacy of Muhammad Ali.&nbsp; Surcharges received from the sale of these coins shall be paid to: (1) the Muhammad Ali Center in Louisville, Kentucky; (2) the Muhammad Ali Institute for Peace and Justice at the University of Louisville; and (3) the Muhammad Ali Parkinson Center and Movement Disorder Clinic.

recently , new information on the @xmath8-propagation in the nucleus has been obtained from a coherent pion decay experiment @xcite and from a @xmath9 spin - flip transfer experiment @xcite . in the first experiment the @xmath1c(@xmath4he , t@xmath2)@xmath1c(g.s . ) reaction was used to measure the isovector spin - longitudinal ( @xmath10 ) response function in the @xmath0 resonance region . in the second experiment the spin observables of the @xmath9 reaction were used to decompose the charge exchange cross section in the @xmath0 resonance region into its spin - longitudinal ( lo ) and spin - transverse ( tr ) components . similar to the @xmath11-nucleus total cross section data @xcite the lo cross sections of both reactions show a substantial downward energy shift of the @xmath0 resonance in nuclei , as compared to the proton target . from a consistent @xmath0-hole model analysis of pion and photon scattering , and charge exchange reactions @xcite it is found that a large part of the observed shift is due to a nuclear medium effect on the lo response function . the medium effect is caused by the strongly attractive , energy dependent @xmath0-particle - nucleon - hole residual interaction @xmath12 . in refs . @xcite it was shown that @xmath12 can be well described by the @xmath6 model ( @xcite and references therein ) . the strong attraction of the @xmath11-exchange in the lo channel produces a collective pion mode at excitation energies of @xmath13 mev in the laboratory frame . the collectivity shifts the lo response function down in energy by 60 mev relative to the spin - transverse ( @xmath14 ) response function . other , smaller effects come from @xmath0 conversion processes , such as @xmath15 @xcite , and from projectile excitation @xcite . in the present paper we apply the @xmath0-hole model of refs . @xcite to the calculation of the damping of the collective pion mode in the nucleus . the major decay channels are the coherent pion decay , the quasi - free decay , and the 2p emission . while various calculations for the coherent pion decay were published already in refs . @xcite we give here the results for the quasi - free ( @xmath2p ) decay and the 2p emission . since the coupling interaction for the quasi - free decay is known we can use this process to study the distortion effects on the outgoing pion and proton wave functions . for the 2p emission process we assume a @xmath6 interaction . we show that the 2p emission in the @xmath0 resonance energy region is dominated by the zero - range landau - migdal interaction , the strength of which can be exctracted from the data . both the pion induced reactions and the charge exchange reactions are well reproduced by calculations with a landau - migdal parameter in the range of @xmath16 . in this section we describe the @xmath0-hole model used in the analysis of the experimental data . the formalism and the methods of calculation were presented already in recent papers @xcite . in the present paper we discuss only those formulas which are connected with the quasi - free decay and the 2p emission . we start our formulation by writing down the fivefold differential cross section for the charge exchange reaction @xmath17 in the lab frame ( @xmath18 , @xmath19 ) @xmath20 here @xmath21 ( @xmath22 ) and @xmath23 ( @xmath24 ) denote the target ( excited intermediate nucleus ) and projectile ( ejectile ) , respectively . the @xmath22 system de - excites to the residual nucleus @xmath25 by emission of the particles @xmath26 and @xmath27 which carry four - momenta ( @xmath28 and ( @xmath29 , respectively . @xmath30 stands for the mass of particle @xmath31 ) and ( @xmath32 ) denotes the four - momentum transfer in the excitation process . in case that one of the outgoing particles is a boson ( e.g. in the quasi - free decay ) the according normalisation factor m / e has to be replaced by 1/2e . the full four body kinematics in the final reaction channel is included . the transition amplitude @xmath33 for the decay process is defined as @xmath34_{({\cal a } ) } \mid v_{cd,\delta } \mid \psi\rangle \label{eq2}\ ] ] where @xmath35 denotes the @xmath0 decay interaction that will be specified later . @xmath36 and @xmath37 are the distorted wave functions of the outgoing particles @xmath26 and @xmath27 , respectively , and @xmath38 is the wave function of the residual nucleus . the index @xmath39 indicates that in case of the 2p emission the wave functions of the two outgoing identical fermions have to be antisymmetrized . the wave function @xmath40 describes the intermediate @xmath22 system and is defined by @xcite @xmath41 where @xmath42 is the doorway state excited initially by the reaction . the green s function @xmath43 describes the propagation of the ( @xmath22 ) system and is approximated by that of the isobar - hole model @xcite . @xmath44 is the energy dependent free decay width of the @xmath0 , @xmath45 is the hamiltonian of the hole nucleus @xmath46 , @xmath47 and @xmath48 are the kinetic energy operator and the @xmath0-nucleus one - body potential , respectively , and @xmath12 is the @xmath0-hole residual interaction . for the calculation of @xmath49 we use the same input parameters as used in refs . the pauli blocking effects are assumed to be included in the average @xmath0-nucleus one - body potential , which we fixed by re - analysing the relevant scattering data @xcite . we refer the reader for more details to refs . @xcite . for charge exchange reactions the doorway state @xmath42 has the explicit form @xcite @xmath50 where @xmath51 and @xmath52 denote the projectile and ejectile distorted wave functions , respectively , and @xmath53 and @xmath54 are the corresponding intrinsic wave functions of the projectile @xmath23 and ejectile @xmath24 ; @xmath55 describes the target ground state wave function . the effective @xmath56 transition operator for the charge exchange process is denoted by @xmath57 . the round bra ( @xmath58 on the right side of eq . ( [ eq4 ] ) denotes the integration with respect to the projectile coordinates only . for pion induced reactions the coincidence cross section in the lab frame is threefold differential @xmath59 where ( @xmath60 ) is the four - momentum of the incident pion . now the doorway state has the form @xcite @xmath61 where @xmath62 and @xmath63 are the spin and isospin transition operators , respectively , that convert a nucleon into a @xmath0(1232 ) isobar . the coupling constant @xmath64 is fixed from pion - nucleon scattering data and has the value @xmath65 . the index @xmath66 distinguishes between @xmath67 scattering . 0.4 cm in case of the @xmath1c(@xmath2,@xmath2p)@xmath3b and @xmath1c(@xmath4he , t@xmath2p)@xmath3b reactions the decay interaction @xmath35 of eq . ( [ eq2 ] ) is represented by @xmath68 note that this interaction has no free parameter and is known from elastic pion scattering in the @xmath0 resonance region . the explicit formulas for the quasi - free decay of the @xmath0 are given in appendix [ app1 ] . in case of the @xmath1c(@xmath2,pp)@xmath5b and @xmath1c(@xmath4he , tpp)@xmath5b reactions the interaction for the process @xmath69 is described by a @xmath70 model @xcite : @xmath71 with @xmath72 in eq . ( [ eq8 ] ) , @xmath73 and @xmath74 are the energy and three - momentum transfer involved in the interaction @xmath69 , respectively . the interaction @xmath75 is the so - called landau - migdal term . it describes the short range correlations for @xmath76 transitions . the special value for the landau - migdal parameter @xmath77 ( in units of @xmath78 800 mev @xmath79 ) is known as the ` minimal @xmath80 ' because it cancels out the attractive short range part of the @xmath11-echange potential @xcite . the @xmath11- and @xmath81-exchange potentials @xmath82 and @xmath83 are defined consistently with the potentials for the residual interaction : @xmath84 @xmath85 in the eqs . ( [ eq9 ] ) and ( [ eq10 ] ) , @xmath86 is the four - momentum transfer in the decay process , @xmath87 and @xmath88 ( @xmath89 , @xmath90 ) are the mass and cutoff mass of the @xmath11 ( @xmath81 ) , respectively . the various parameters are fixed as follows : @xmath91 , @xmath92 , @xmath93 gev , @xmath94 gev , @xmath95 gev , and @xmath96 gev . as a consequence of the pauli principle the wave functions of the two outgoing protons have to be antisymmetrized . this leads to two contributions to the 2p emission process , namely the direct and the exchange term ( see fig . 1 ) . the antisymmetrization has to be carried out only for the finite - range @xmath11- and @xmath81-exchange potentials . the landau - migdal term is a zero - range interaction and has not to be antisymmetrized . this treatment of the @xmath69 interaction is in line with microscopic nuclear structure calculations @xcite and microscopic g - matrix calculations @xcite . therefore the landau - migdal parameter @xmath80 extracted from the 2p emission reactions can be directly compared with the values found in these calculations @xcite . the explicit formulas for the 2p emission process induced by the decay of the @xmath0 in the nucleus are derived in appendix [ app2 ] . with the formalism described in sec . ii we have calculated cross sections for the quasi - free decay reactions @xmath1c(@xmath2,@xmath2p)@xmath3b and @xmath1c(@xmath97he , t@xmath2p)@xmath3b and the 2p emission reactions @xmath1c(@xmath2,@xmath2pp)@xmath5b and @xmath1c(@xmath97he , t@xmath2pp)@xmath5b . while the pion induced reactions are truely exclusive with the decay particles measured in coincidence at given energies and angles the decay cross sections of the charge exchange reaction have been integrated over a certain kinematical range , as determined by the geometry of the diogene detector @xcite . therefore the integrated cross sections for ( @xmath97he , t ) induced processes are in a way less exclusive than the pion induced reactions and show only the gross features of the process . furthermore , our calculations treat the distorsion effects on the incoming and outgoing particles in the adequate frameworks . in the pion induced reaction the distorsion of the incoming pion is treated within the isobar hole model while the distorsion of the decay pion and protons is described by optical model wave functions @xcite . in the ( @xmath97he , t ) charge exchange reaction the projectile and ejectile and the decay particles are described by optical model wave functions , whereas the @xmath0 propagation through the nucleus is again treated within the isobar - hole model . in fig . 2 we compare the results of our calculations for the @xmath1c(@xmath2,p@xmath2)@xmath3b reaction to the data of ref . @xcite at the pion kinetic energy of @xmath98 mev . in the experiment the angles of the outgoing proton and pion were fixed at @xmath99 and @xmath100 , respectively , in coplanar geometry . the threefold differential cross section is plotted versus the kinetic energy of the outgoing proton . three different calculations are compared to the data . the dashed curve shows the result of our calculations with @xmath101 while the dot - dashed curve shows the result with @xmath102 . by comparison of both curves one recognizes that the inclusion of the residual interaction reduces the quasi - free decay cross section by a factor of @xmath103 . this reduction is due to the absorption taking place in the multiple scattering of the pion . a similar reduction factor is also observed in the total pion - nucleus cross section @xcite . the solid curve shows the result with additional inclusion of the distortion effect on the outgoing proton and pion wave functions . the distortion effect leads to a further reduction of the cross section by a factor of @xmath104 . we describe the relative motion of the decay particles with respect to the residual nucleus by optical model wave functions . this is a consistent method within the framework of direct nuclear reaction theory and has been used in the analysis of other reactions , like a(e , e pp ) . for the calculation of the proton and pion wave functions we used the optical potential parameters , as derived from elastic proton - nucleus @xcite and elastic pion - nucleus scattering @xcite . using these optical model wave functions we overestimate the absorption and thus obtain a lower limit for the @xmath1c(@xmath2,p@xmath2)@xmath3b cross section . a comparison of the solid curve with the data shows that we underestimate the data by @xmath105% . this is in agreement with our expectation and assures us that our treatment of the distortion effects is reasonable . in the following calculations we will use the same model for the description of the distortion effects on the outgoing particles . 0.3 cm 0.3 cm in fig . 3 we show the results for the @xmath1c(@xmath2,pp)@xmath5b cross section at @xmath106 = 165 mev . the experiment was performed in coplanar geometry with the angle of proton 1 fixed at @xmath107 . the threefold differential cross section is plotted versus the angle of proton 2 . the dashed curve shows the result of our calculation with @xmath101 while the dashed - dotted curve shows the result with @xmath102 . the inclusion of the multiple scattering of the pion in the medium results again in a reduction of the cross section by a factor of @xmath103 . the solid curve shows the result with additional inclusion of the distortion effect on the outgoing proton wave functions . this leads to a further reduction of the cross section by a factor of @xmath108 . the calculations shown here were performed with a minimal landau - migdal parameter @xmath109 in the 2p emission matrix element , which gives a very good agreement with the data @xcite . neglection of the @xmath11- and @xmath81-exchange potentials in the decay interaction leads to almost the same results . thus the landau - migdal term is the most important ingredient to the @xmath69 interaction . this is a consequence of the large momentum and energy transfer involved in the @xmath69 decay process leading to a very short ranged interaction . we remark that the determination of the @xmath80 parameter in the ( @xmath2,pp)-reaction is rather direct since this reaction is dominated by the intermediate @xmath110 excitation . on the other hand , in case of the @xmath1c(@xmath2,pn)@xmath5c reaction @xcite or photon induced 2p emission reactions @xcite many competing processes are possible and the landau - migdal parameter @xmath80 can only be extracted in an indirect way . in fig . 4 we study the same reaction as in fig . 3 ; here the two protons were detected at @xmath111 and @xmath112 , and the cross section is plotted as function of the kinetic energy of proton 1 . the curves shown have the same meaning as in fig . note that the data are given in arbitrary units . thus the data are normalized to the solid curve . the inclusion of the residual interaction and the inclusion of the distortion effects reduces the magnitude again by a factor of @xmath103 and @xmath108 , respectively . the dependence of the cross section on the kinetic energy of the proton 1 is reproduced well . the slight deviation of the calculated cross section from the data at low kinetic energies could indicate that the treatment of the distortion on the outgoing nucleons should be improved for these energies . in fig . 5 ( a ) we compare our results for the @xmath1c(@xmath97he , tp@xmath2 ) reaction with the data of hennino _ et al . _ @xcite . the data are integrated over the kinematically allowed pion and proton energies as well as pion and proton angles . the solid curve shows our calculation with inclusion of the residual interaction @xmath12 and with inclusion of the distortion effects on the outgoing particles . we see no effect of the residual interaction in this energy and angle integrated cross section , i. e. the cross sections with and without inclusion of @xmath12 are the same . this is an indication that the p@xmath2 events in this reaction come only from the nuclear surface . 0.3 cm in fig . 5 ( b ) we compare our microscopically calculated @xmath1c(@xmath97he , tpp ) coincidence spectra with the data of hennino _ et al . the data are integrated over the phase space of both outgoing protons . two calculations are compared to the data : the solid curve shows the result with @xmath102 while the dashed curve shows the result with @xmath101 . in both cases the distortion effects are taken into account . in order to reproduce the magnitude of the experimental data we used a landau - migdal parameter of @xmath113 . this value is consistent with that found in the ( @xmath2,pp)-reactions of figs . 3 and 4 . both values for @xmath80 lie in the range from 0.25 0.35 and are thus in agreement with values of the landau - migdal parameter found in microscopic g - matrix calculations @xcite . in conclusion , we have presented microscopic calculations for the quasi - free decay of the @xmath0 resonance and the 2p emission in nuclei induced by pion absorption and by charge exchange reactions . these calculations are performed within the framework of the @xmath0-hole model and are consistent with our former calculations of inclusive and exclusive reactions on nuclei . since the coupling interaction for the quasi - free decay is known we use this process to study the distortion effects on the outgoing pion and proton wave functions . in the 2p emission reactions we describe the @xmath0+n@xmath7 n+n decay interaction by a @xmath70 model , which is consistent with our description of the residual interaction . we find that the @xmath69 decay interaction is dominated by the zero - range landau - migdal term . the data for both the ( @xmath2,pp ) reaction and the ( @xmath97he , tpp ) reaction are well reproduced by calculations with a landau - migdal parameter in the range of @xmath16 . this work is supported in part by the u.s . department of energy under contract de - fg05 - 84-er40145 . in this appendix we derive the explicit formulas for the transition amplitude of the quasi - free decay . inserting the decay interaction @xmath114 of eq . ( [ eq7 ] ) into eq . ( [ eq2 ] ) one can write the transition amplitude in the following way : @xmath115 here @xmath116 and @xmath117 represent the total angular momentum and the magnetic quantum number of the final ( a-1)-nucleus ; @xmath118 and @xmath119 are the three - momentum and the spin projection of the outgoing proton ; @xmath120 is the three - momentum of the outgoing pion . we expand the wave function @xmath121 of the @xmath0-hole state in terms of the channel wave functions @xcite @xmath122_{j_t m_t } \rangle = \sum_{m_{\delta}m_{h } } ( j_{\delta}\ , m_{\delta}\ ; j_{h}\ , m_{h}\ , | \ , j_t\ , m_t ) \ ; \mid y_{j_{\delta}m_{\delta}}\phi_{j_{h}m_{h}}\rangle \ ; , \label{agl2}\ ] ] where @xmath123 is the spin - angle wave function of the @xmath0 and @xmath124 is the hole wave function of nucleus b. thus we obtain @xcite @xmath125_{j_t m_t}\rangle \ ; .\ ] ] in ( [ agl3 ] ) @xmath126 denotes the total number of allowed @xmath0-hole states . the radial wave function is then given by the inversion of eq . ( [ agl3 ] ) : @xmath127_{j_t m_t } \mid \psi \rangle \ ; .\ ] ] the wave functions of the decay nucleon and the outgoing pion are also expanded in multipoles : @xmath128_{j_p m_p } \;\ ; , \label{agl6}\ ] ] @xmath129 where @xmath130 and @xmath131 denote the distorted radial wave functions of the outgoing proton and pion , respectively . using the expansion of eq . ( [ agl3 ] ) for the wave function @xmath132 and using the expansions of eqs . ( [ agl6 ] ) and ( [ agl7 ] ) for the outgoing nucleon and pion wave functions we can rewrite the transition amplitudes for the quasi - free decay of the @xmath0 as @xmath133 in eq . ( [ agl5 ] ) the clebsch - gordan coefficient @xmath134 describes the isospin coupling coefficient of the decay process and @xmath135 . here we show the explicit formulas for the 2p emission processes . due to the antisymmetrization of the two outgoing protons the transition amplitude for the 2p emission consists of the sum of the direct and exchange transition amplitudes . as a consequence of the arguments given in section [ decay ] we have to antisymmetrize only the @xmath11- and @xmath81-exchange interactions . the transition amplitude is given by ( see fig . 1 ) : @xmath136 _ { \cal a } \mid v_{pp,\delta } \mid \psi \rangle \\ & = & \frac{1}{\sqrt{2}}\ ; \left ( \langle j^{'}_{h}m^{'}_{h } ; 1 ; 2 \mid v_{\pi } + v_{\rho } + v_{\delta}\mid \psi \rangle \ ; - \ ; \langle j^{'}_{h}m^{'}_{h } ; 2 ; 1 \mid v_{\pi}+v_{\rho } \mid \psi \rangle \right ) \;\ ; . \label{bgl2}\end{aligned}\ ] ] in eqs . ( [ bgl1 ] ) and ( [ bgl2 ] ) @xmath116 and @xmath117 represent the total angular momentum and the magnetic quantum number of the final ( a-2)-nucleus ; @xmath137 and @xmath138 ( @xmath139 , @xmath140 ) are the three - momentum and the spin projection of the outgoing proton 1 ( 2 ) , respectively . using the expansion of eq . ( [ agl3 ] ) for the wave function @xmath132 and the multipole expansion of the nucleon wave functions of eq . ( [ agl6 ] ) we can write the matrix element for the direct decay graph in the following way : @xmath141 here @xmath142 denotes the radial hole wave function with quantum numbers @xmath143 . the non - local potential @xmath144 is the sum of the central and tensor part of the decay interaction @xcite : @xmath145 for the direct matrix element @xmath146 and @xmath147 are the multipole expanded central and tensor parts of @xmath148 @xcite ; for the exchange matrix element they are the multipole expanded central and tensor parts of @xmath149 .

the damping mechanisms of the @xmath0(1232 ) resonance in nuclei are studied by analyzing the quasi - free decay reactions @xmath1c(@xmath2,@xmath2p)@xmath3b and @xmath1c(@xmath4he , t@xmath2p)@xmath3b and the 2p emission reactions @xmath1c(@xmath2,pp)@xmath5b and @xmath1c(@xmath4he , tpp)@xmath5b . the coincidence cross sections are calculated within the framework of the isobar - hole model . it is found that the 2p emission process induced by the decay of the @xmath0 resonance in the nucleus can be consistently described by a @xmath6 model for the @xmath0+n@xmath7 n+n decay interaction .

treatment with dalbavancin was well tolerated.the long half - life of dalbavancin did not lead to any safety concerns . over the last decade , the usa has witnessed a dramatic increase in the incidence of community - acquired skin infections , an increasing proportion of which are a consequence of methicillin - resistant staphylococcus aureus ( mrsa ) , reinforcing the need for new and effective antibacterial therapies in this disease [ 14 ] . dalbavancin is a lipoglycopeptide with activity against gram - positive organisms , including mrsa , through interference with bacterial cell wall formation by preventing cross - linking of peptidoglycans . dalbavancin has a distinctive pharmacokinetic profile , with a terminal half - life of 14.4 days , which allows for infrequent intravenous dosing . it is not metabolized , does not interact with cytochrome p450 enzymes , and is eliminated via both hepatic and renal routes . after entering human studies in 2003 , dalbavancin has been studied in 14 phase i , two phase ii , and five phase iii studies [ 511 ] . presented here are safety data from patients enrolled in all seven phase ii and phase iii studies in the dalbavancin clinical development program that lead to us and european regulatory approval for the treatment of acute bacterial skin and skin structure infections ( absssi ) [ 12 , 13 ] . all phase ii and phase iii clinical trials for the treatment of uncomplicated and complicated skin infection , catheter - related bloodstream infection and absssi supported by the sponsor and submitted to the regulatory authorities for review and marketing approval are included in the analyses ( table 1 ) . as dalbavancin was not available commercially prior to 2013 all studies were randomized controlled trials comparing dalbavancin with a comparator agent and were designed as non - inferiority trials . the protocols for all studies were reviewed by the local ethics committees of participating institutions and were consistent with the declaration of helsinki . all patients provided written informed consent.table 1treatment - related adverse events in randomized and treated patients in phase ii / iii clinical development programstudiesdalbavancincomparator n two doses one dose n regimenall phase ii / iii studies177814283501224phase ii studies81542755catheter - related bloodstream infections ver001 - 4 4034634vancomycinskin and skin structure infections ver001 - 5 412021 21standard of carephase iii studies169713743231169uncomplicated skin and skin structure infection ver001 - 8 ( data on file , allergan plc . ) 36794273186cefazolincomplicated skin and skin structure infection ver001 - 16 ( data on file , allergan plc . ) 107575049vancomycin ver001 - 9 5715710283linezolidacute bacterial skin and skin structure infection dur001 - 301 ( discover 1 ) 2842840284vancomycin / linezolid dur001 - 302 ( discover 2 ) 3683680367vancomycin / linezolidcomparator agents include cephalosporins , vancomycin , oxacillin , nafcillin and linezolid . studies ver001 - 4 , 5 , and 16 were open - label trials ; all others were double blinded . discover 1 and discover 2 clinicaltrials.gov numbers , nct01339091 and nct01431339 intravenous dalbavancin 1000 mg on day 1 followed by 500 mg on day 8 intravenous dalbavancin 1000 mg on day 1 intravenous dalbavancin 1100 mg treatment - related adverse events in randomized and treated patients in phase ii / iii clinical development program comparator agents include cephalosporins , vancomycin , oxacillin , nafcillin and linezolid . studies ver001 - 4 , 5 , and 16 were open - label trials ; all others were double blinded . discover 1 and discover 2 clinicaltrials.gov numbers , nct01339091 and nct01431339 intravenous dalbavancin 1000 mg on day 1 followed by 500 mg on day 8 intravenous dalbavancin 1000 mg on day 1 intravenous dalbavancin 1100 mg dalbavancin was delivered intravenously over 30 min as 1000 mg on day 1 and 500 mg on day 8 . in ver001 - 8 and ver001 - 16 , a total of 273 and 49 patients , respectively , with uncomplicated skin infection were given the option of stopping after the first 1000-mg dose . in ver001 - 5 , a total of 20 patients received a single 1100-mg dose . no adjustment for weight or body mass index ( bmi ) was required in the clinical program . follow - up was performed through day 28 in all studies except the two pivotal studies for absssi ( discover 1 and discover 2 ) , where the last follow - up visit occurred at day 70 . all patients in the phase ii and phase iii studies presented with an infection of the skin or , in one phase ii study , a catheter - related bloodstream infection , and are included in the safety analyses . each protocol outlined the requirements for reporting of adverse events , but , briefly , all observed or volunteered adverse events , regardless of treatment group or suspected causal relationship to study drug , were reported from the time that the patient provided informed consent through the last follow - up visit . adverse events included clinically significant symptoms and signs , changes in physical examination findings , hypersensitivity , and progression or worsening of underlying disease . severity was assessed as mild , moderate , or severe based on the investigator s clinical impression rather than a result of specific criteria for defining the severity of an event . causality was determined by the investigator for all adverse events as unrelated , unlikely related , possibly related , or probably related to the study drug . serious adverse events are those that result in death , are life - threatening , require inpatient hospitalization or prolongation of existing hospitalization , result in persistent or significant disability or incapacity , result in congenital anomaly or birth defect , or are assessed as being a medically important event based on medical and scientific judgment . the timing of laboratory assessments , including hematology and biochemistry parameters , was defined in each protocol and performed at baseline and at periodic intervals , including days 3 , 8 , 14 , or 28 . in all safety analyses , data are pooled at the patient level across studies , as is typical for the purposes of reporting safety data to regulatory authorities and in retrospective reviews of adverse drug reactions [ 14 , 15 ] . the safety analyses included patients who were randomized and received a dose of study drug in all the phase ii or phase iii clinical trials completed through 2013 . patients received the two - dose regimen of dalbavancin or , where permitted in protocols enrolling patients with uncomplicated skin infections , a single 1000-mg dose . for all analyses of treatment - emergent adverse events ( teaes ) , if the same adverse event was reported for the same patient more than once , the adverse event was counted only once for that preferred term and at the highest intensity and strongest relationship to study drug . differences between treatment groups were analyzed using fisher s exact test for dichotomous variables ( sex , ethnicity , race ) and the wilcoxon rank - sum test for continuous variables ( age , bmi , creatinine clearance ) , prospectively for patient demographics and post hoc , as relevant , for other analyses of interest . total adverse event comparisons were analyzed using a cochran mantel haenszel analysis to adjust for study and a log - normal , poisson regression model adjusted by study on total number of treatment - related adverse events per patient . no adjustments were made for multiple comparisons , and p values are presented for descriptive purposes only . safety outcomes are presented as verbatim descriptions of adverse events and were coded using version 14 or higher of meddra . all phase ii and phase iii clinical trials for the treatment of uncomplicated and complicated skin infection , catheter - related bloodstream infection and absssi supported by the sponsor and submitted to the regulatory authorities for review and marketing approval are included in the analyses ( table 1 ) . as dalbavancin was not available commercially prior to 2013 all studies were randomized controlled trials comparing dalbavancin with a comparator agent and were designed as non - inferiority trials . the protocols for all studies were reviewed by the local ethics committees of participating institutions and were consistent with the declaration of helsinki . all patients provided written informed consent.table 1treatment - related adverse events in randomized and treated patients in phase ii / iii clinical development programstudiesdalbavancincomparator n two doses one dose n regimenall phase ii / iii studies177814283501224phase ii studies81542755catheter - related bloodstream infections ver001 - 4 4034634vancomycinskin and skin structure infections ver001 - 5 412021 21standard of carephase iii studies169713743231169uncomplicated skin and skin structure infection ver001 - 8 ( data on file , allergan plc . ) 36794273186cefazolincomplicated skin and skin structure infection ver001 - 16 ( data on file , allergan plc . ) 107575049vancomycin ver001 - 9 5715710283linezolidacute bacterial skin and skin structure infection dur001 - 301 ( discover 1 ) 2842840284vancomycin / linezolid dur001 - 302 ( discover 2 ) 3683680367vancomycin / linezolidcomparator agents include cephalosporins , vancomycin , oxacillin , nafcillin and linezolid . studies ver001 - 4 , 5 , and 16 were open - label trials ; all others were double blinded . discover 1 and discover 2 clinicaltrials.gov numbers , nct01339091 and nct01431339 intravenous dalbavancin 1000 mg on day 1 followed by 500 mg on day 8 intravenous dalbavancin 1000 mg on day 1 intravenous dalbavancin 1100 mg treatment - related adverse events in randomized and treated patients in phase ii / iii clinical development program comparator agents include cephalosporins , vancomycin , oxacillin , nafcillin and linezolid . studies ver001 - 4 , 5 , and 16 were open - label trials ; all others were double blinded . discover 1 and discover 2 clinicaltrials.gov numbers , nct01339091 and nct01431339 intravenous dalbavancin 1000 mg on day 1 followed by 500 mg on day 8 intravenous dalbavancin 1000 mg on day 1 intravenous dalbavancin 1100 mg dalbavancin was delivered intravenously over 30 min as 1000 mg on day 1 and 500 mg on day 8 . in ver001 - 8 and ver001 - 16 , a total of 273 and 49 patients , respectively , with uncomplicated skin infection were given the option of stopping after the first 1000-mg dose . in ver001 - 5 , a total of 20 patients received a single 1100-mg dose . no adjustment for weight or body mass index ( bmi ) was required in the clinical program . follow - up was performed through day 28 in all studies except the two pivotal studies for absssi ( discover 1 and discover 2 ) , where the last follow - up visit occurred at day 70 . all patients in the phase ii and phase iii studies presented with an infection of the skin or , in one phase ii study , a catheter - related bloodstream infection , and are included in the safety analyses . each protocol outlined the requirements for reporting of adverse events , but , briefly , all observed or volunteered adverse events , regardless of treatment group or suspected causal relationship to study drug , were reported from the time that the patient provided informed consent through the last follow - up visit . adverse events included clinically significant symptoms and signs , changes in physical examination findings , hypersensitivity , and progression or worsening of underlying disease . severity was assessed as mild , moderate , or severe based on the investigator s clinical impression rather than a result of specific criteria for defining the severity of an event . causality was determined by the investigator for all adverse events as unrelated , unlikely related , possibly related , or probably related to the study drug . serious adverse events are those that result in death , are life - threatening , require inpatient hospitalization or prolongation of existing hospitalization , result in persistent or significant disability or incapacity , result in congenital anomaly or birth defect , or are assessed as being a medically important event based on medical and scientific judgment . the timing of laboratory assessments , including hematology and biochemistry parameters , was defined in each protocol and performed at baseline and at periodic intervals , including days 3 , 8 , 14 , or 28 . in all safety analyses , data are pooled at the patient level across studies , as is typical for the purposes of reporting safety data to regulatory authorities and in retrospective reviews of adverse drug reactions [ 14 , 15 ] . the safety analyses included patients who were randomized and received a dose of study drug in all the phase ii or phase iii clinical trials completed through 2013 . patients received the two - dose regimen of dalbavancin or , where permitted in protocols enrolling patients with uncomplicated skin infections , a single 1000-mg dose . for all analyses of treatment - emergent adverse events ( teaes ) , if the same adverse event was reported for the same patient more than once , the adverse event was counted only once for that preferred term and at the highest intensity and strongest relationship to study drug . differences between treatment groups were analyzed using fisher s exact test for dichotomous variables ( sex , ethnicity , race ) and the wilcoxon rank - sum test for continuous variables ( age , bmi , creatinine clearance ) , prospectively for patient demographics and post hoc , as relevant , for other analyses of interest . total adverse event comparisons were analyzed using a cochran mantel haenszel analysis to adjust for study and a log - normal , poisson regression model adjusted by study on total number of treatment - related adverse events per patient . no adjustments were made for multiple comparisons , and p values are presented for descriptive purposes only . safety outcomes are presented as verbatim descriptions of adverse events and were coded using version 14 or higher of meddra . a total of 1778 patients enrolled in the phase ii / iii program were randomized and treated with dalbavancin , and 1224 received a comparator agent ( fig . 1 , tables 1 and 2 ) . the median age of all patients receiving dalbavancin was 47.0 years , 17.6 % of patients were aged > 65 years , 78 % were white , 64.3 % were from north america , and 71.6 % of patients exceeded a bmi of 25 kg / m . small differences between treatment groups were observed in the distribution of race and location and type of infection.fig . absssi acute bacterial skin and skin structure infection , csssi complicated skin and skin structure infection , d / c patients discontinued from the study , usssi uncomplicated skin and skin structure infectiontable 2demographics of patients enrolled in phase ii / iii clinical development programdalbavancin ( n = 1778)comparator ( n = 1224)age ( years ) n 17781224 mean48.349.2 sd16.4416.51 median47.049.0 min ; max16 ; 9318 ; 92age distribution ( years ) < 651465 ( 82.4)995 ( 81.3 ) 65313 ( 17.6)229 ( 18.7)sex male1066 ( 60.0)711 ( 58.1 ) female712 ( 40.0)513 ( 41.9)race white 1388 ( 78.1)1008 ( 82.4 ) black or african american143 ( 8.0)88 ( 7.2 ) asian 36 ( 2.0)41 ( 3.3 ) american indian or alaska native5 ( 0.3)4 ( 0.3 ) native hawaiian or other pacific islander1 ( 0.1)1 ( 0.1 ) other 205 ( 11.5)82 ( 6.7)body mass index ( kg / m ) n 17611218 mean29.929.4 sd8.187.96 median27.927.8 min ; max14 ; 9814 ; 91body mass index distribution ( kg / m ) < 18.523 ( 1.3)18 ( 1.5 ) 18.5 to < 25465 ( 26.2)359 ( 29.3 ) 251273 ( 71.6)841 ( 68.7 ) unknown17 ( 1.0)6 ( 0.5)indication csssi / absssi 1294 ( 72.8)973 ( 79.5 ) usssi 444 ( 25.0)217 ( 17.7 ) catheter - related bloodstream infections40 ( 2.2)34 ( 2.8)location north america1143 ( 64.3)689 ( 56.3 ) eastern europe and south africa395 ( 22.2)389 ( 31.8 ) western europe216 ( 12.1)118 ( 9.6 ) asia pacific24 ( 1.3)28 ( 2.3)temperature 38 c at baseline , n / n ( % ) 549/649 ( 84.6)552/649 ( 85.0)median ( range ) infection area ( cm)324 ( 265100)367 ( 723922)data are presented as n ( % ) unless otherwise indicated absssi acute bacterial skin and skin structure infection , csssi complicated skin and skin structure infection , sd standard deviation , usssi uncomplicated skin and skin structure infection comparisons with p < 0.05 by fisher s exact test among patients in the absssi studies flow chart of patients included in safety and efficacy analyses . absssi acute bacterial skin and skin structure infection , csssi complicated skin and skin structure infection , d / c patients discontinued from the study , usssi uncomplicated skin and skin structure infection demographics of patients enrolled in phase ii / iii clinical development program data are presented as n ( % ) unless otherwise indicated absssi acute bacterial skin and skin structure infection , csssi complicated skin and skin structure infection , sd standard deviation , usssi uncomplicated skin and skin structure infection comparisons with p < 0.05 by fisher s exact test among patients in the absssi studies approximately 85 % of patients completed the study drug course of therapy , with the most commonly identified reasons for discontinuation of study medication similarly distributed among worsening clinical status , lost to follow - up , an adverse event , and withdrawal of consent . a total of 89 % of patients completed the study ; the most common reasons for not completing the study included withdrawal of consent , death , and lost to follow - up ( table 3).table 3disposition of patients in phase ii / iii clinical development programdalbavancincomparatortotal treated17781224completed study medication1518 ( 85.0)1061 ( 86.5)did not complete study medication219 ( 12.3)143 ( 11.7 ) treatment failure / worsening clinical status25 ( 1.4)16 ( 1.3 ) adverse event49 ( 2.7)31 ( 2.5 ) patient withdrew consent or for reason other than adverse event21 ( 1.2)19 ( 1.5 ) death0 ( 0.0)1 ( 0.1 ) patient lost to follow - up27 ( 1.5)13 ( 1.1 ) patient non - compliance10 ( 0.6)9 ( 0.7 ) withdrawn at investigator s discretion6 ( 0.3)9 ( 0.7 ) other81 ( 4.5)45 ( 3.7)completed study1595 ( 89.4)1098 ( 89.6)did not complete study190 ( 10.6)127 ( 10.4 ) adverse event0 ( 0.0)1 ( 0.1 ) patient withdrew consent42 ( 2.4)22 ( 1.8 ) death10 ( 0.6)13 ( 1.1 ) patient lost to follow - up107 ( 6.0)67 ( 5.5 ) subject noncompliance2 ( 0.1)0 ( 0.0 ) prohibited concomitant medication used1 ( 0.1)0 ( 0.0 ) other28 ( 1.6)24 ( 2.0)data are presented as n ( % ) disposition of patients in phase ii / iii clinical development program data are presented as n ( % ) death was infrequent for either dalbavancin or the comparator regimens ( 0.6 vs. 1.1 % , respectively ) . relative to those treated with comparator , patients receiving dalbavancin experienced fewer teaes ( 44.9 vs. 46.8 % , respectively , p = 0.012 ) , fewer treatment - related adverse events ( 18.4 vs. 20.1 % , respectively , p = 0.014 ) , and fewer treatment - related serious adverse events ( 0.2 vs. 0.7 % , respectively , p = 0.021 ) . of the total number of adverse events , including serious adverse events , fewer were judged by the investigator as likely to be related to dalbavancin relative to the comparator ( table 4 ) . the distribution of mild , moderate , and severe events was similar for each regimen.table 4adverse events in phase ii / iii clinical development programdalbavancin ( n = 1778)comparator ( n = 1224 ) p valuepatients with the ae teae 799 ( 44.9)573 ( 46.8)0.012 treatment - related teae 328 ( 18.4)246 ( 20.1)0.014 serious aes109 ( 6.1)80 ( 6.5)0.266 serious treatment - related aes3 ( 0.2)9 ( 0.7)0.021 discontinuation due to a teae 53 ( 3.0)35 ( 2.9)0.857 discontinuation due to a serious teae 22 ( 1.2)13 ( 1.1)0.660 death10 ( 0.6)14 ( 1.1)0.087number of aes aes , n ( n / patient)2386 ( 1.34)1739 ( 1.42 ) treatment - related aes ( n , % of total)566 ( 23.7)459 ( 26.4)0.0004 serious aes ( n , % of total)135 ( 5.7)100 ( 5.8)ns serious treatment - related aes ( n , % of total)3 ( 0.1)9 ( 0.5)0.036data are presented as n ( % ) unless otherwise indicated ae adverse event , ns not significant , teae treatment - emergent adverse event cochran mantel haenszel analysis , adjusted for study log - normal , poisson regression model adjusted by study on total number of treatment - related adverse events per patient fisher s exact test adverse events in phase ii / iii clinical development program data are presented as n ( % ) unless otherwise indicated ae adverse event , ns not significant , teae treatment - emergent adverse event cochran mantel haenszel analysis , adjusted for study log - normal , poisson regression model adjusted by study on total number of treatment - related adverse events per patient treatment - related serious adverse events occurring in patients treated with dalbavancin included progression of cellulitis , asymptomatic leukopenia in a patient with a baseline white blood cell count of 6.9 10 cells / mm and a nadir of 3.79 10 cells / mm that recovered to baseline by day 29 , and an anaphylactoid reaction ( table 5 ) . the patient with an anaphylactoid reaction was a 22-year - old white male with a history of reactive airway disease and atopy , who had received general anesthetic agents ~3 h earlier and aztreonam intravenously as a bolus immediately prior to treatment with one dose of intravenous dalbavancin . after 15 min of a 30-min infusion , he developed dyspnea , laryngospasm , and a decrease in blood pressure . the dalbavancin infusion was stopped , and he was treated immediately with epinephrine , midazolam , antihistamines , and a 5-day course of prednisone . symptoms and signs associated with the event were considered to be completely resolved within 1 h of discontinuation of the infusion and did not recur.table 5treatment - related serious adverse events in phase ii / iii clinical development programtreatment - related serious adverse eventdalbavancin ( n = 1778)comparator ( n = 1224)total3 ( 0.2)9 ( 0.7 ) leukopenia1 ( 0.1)0 anaphylactoid reaction1 ( 0.1)0 cellulitis1 ( 0.1)1 ( 0.1 ) renal failure acute02 ( 0.2 ) gastrointestinal disorder01 ( 0.1 ) face edema01 ( 0.1 ) pancytopenia01 ( 0.1 ) thrombocytopenia01 ( 0.1 ) nephropathy toxic01 ( 0.1 ) pancreatitis acute01 ( 0.1 ) treatment - related serious adverse events in phase ii / iii clinical development program the most common adverse events with onset after starting study drug treatment were nausea , headache , diarrhea , constipation , vomiting , rash , urinary tract infection , pruritus , and insomnia ( table 6 ) . nausea , diarrhea , and pruritus were the most common treatment - related adverse events , with an incidence of approximately 2 % . the duration of adverse events was similar for dalbavancin and the comparator regimens , with a median of 3.0 and 4.0 days and a mean of 7.7 and 8.0 days , respectively ( fig . additionally , the mean , median , and range of the time to the onset of adverse events were similar on each regimen ( fig . an increase of adverse events was observed at day 8 , seen with both the comparator and dalbavancin ; this is most likely because the protocols required a visit on day 8 and not necessarily on days 47 , allowing for a greater opportunity to report an event on that day.table 6treatment - emergent adverse events at > 2 % in either treatment regimen in phase ii / iii clinical development programdalbavancin ( n = 1778)comparator ( n = 1224)treatment - emergent adverse events799 ( 44.9)573 ( 46.8 ) nausea98 ( 5.5)78 ( 6.4 ) headache83 ( 4.7)59 ( 4.8 ) diarrhea79 ( 4.4)72 ( 5.9 ) constipation52 ( 2.9)30 ( 2.5 ) vomiting50 ( 2.8)37 ( 3.0 ) rash38 ( 2.1)22 ( 1.8 ) urinary tract infection36 ( 2.0)16 ( 1.3 ) pruritus32 ( 1.8)35 ( 2.9 ) insomnia27 ( 1.5)30 ( 2.5)treatment - related and treatment - emergent adverse events nausea49 ( 2.8)40 ( 3.3 ) diarrhea45 ( 2.5)45 ( 3.7 ) pruritus*11 ( 0.6)23 ( 1.9 ) * p = 0.001fig . teae treatment - emergent ae treatment - emergent adverse events at > 2 % in either treatment regimen in phase ii / iii clinical development program duration of adverse events day of onset of adverse events ( ae ) . teae treatment - emergent ae adverse event rates with dalbavancin or comparator were similar when assessed by age , sex , or race , as were those related to impaired renal or hepatic function ( table 7 ) . similar numbers of patients experienced an infusion - related adverse event ; however , given that dalbavancin is dosed only on day 1 and day 8 , restricting the reported adverse events to only those 2 days of active dalbavancin infusion ( i.e. , not including placebo infusions given on other days during the blinded clinical trials ) identified far fewer infusion - associated events in patients treated with dalbavancin ( 12 events in 1778 patients vs. 53 events in 1224 comparator patients ) . red man syndrome was not identified in any patient receiving dalbavancin in the phase ii / iii clinical program , although two such cases were reported in phase i studies.table 7patients with adverse events of special interest in phase ii / iii clinical development programdalbavancincomparatorinfusion - associated aes40/1778 ( 2.2)38/1224 ( 3.1 ) number of infusion - associated events4855 number of events on day of active infusion1253renal - associated aes33/1778 ( 1.9)24/1224 ( 2.0 ) treatment - related renal - associated aes3 ( 0.2)5 ( 0.4 ) serious renal - associated aes3 ( 0.2)6 ( 0.5 ) treatment - related serious renal - associated aes03 ( 0.2)hepatobiliary aes19/1778 ( 1.1)9/1224 ( 0.7 ) treatment - related treatment - emergent hepatobiliary aes6 ( 0.3)1 ( 0.1)serious treatment - emergent hepatobiliary aes all treatment - emergent hepatobiliary aes3 ( 0.2)2 ( 0.2 ) treatment - related hepatobiliary aes00teae by age , sex , or race < 65 years of age641/1465 ( 43.8)465/995 ( 46.7 ) 65 years of age158/313 ( 50.5)108/229 ( 47.2 ) male449/1066 ( 42.1)308/711 ( 43.3 ) female350/712 ( 49.2)265/513 ( 51.7 ) white579/1388 ( 41.7)448/1008 ( 44.4 ) black90/143 ( 62.9)58/88 ( 65.9 ) other130/247 ( 52.6)67/127 ( 52.8)data are presented as n ( % ) or n / n ( % ) unless otherwise indicated ae adverse event , teae treatment - emergent adverse event patients with adverse events of special interest in phase ii / iii clinical development program data are presented as n ( % ) or n / n ( % ) unless otherwise indicated ae adverse event , teae treatment - emergent adverse event laboratory assessments performed during the course of the clinical trials demonstrated generally similar laboratory changes post - baseline in patients treated with either dalbavancin or comparator ( table 8) . no overall difference was observed in the post - baseline measurements of alanine transaminase ( alt ) among patients enrolled in the phase ii or iii studies , including subjects with an elevated alt measurement at baseline . slightly more patients in the dalbavancin treatment group with a normal alt value at baseline had a post - baseline alt elevation greater than three times the upper limit of normal ( 0.8 vs. 0.2 % receiving dalbavancin and comparator , respectively ) , but fewer patients had a similar degree of elevation if the alt was abnormal at baseline ( 12.7 vs. 14.2 % receiving dalbavancin and comparator , respectively ) . in eight of these 12 patients with a normal alt at baseline , one or more significant underlying hepatic disorders were identified , such as hepatitis c , hepatitis b , acute cholecystitis , or active alcohol abuse as measured by carbohydrate - deficient transferrin . no case met the criteria for hy s law . with regard to renal function , an increase in creatinine was less frequently observed in patients receiving dalbavancin , and was most evident in subjects with a normal creatinine at baseline.table 8selected laboratory measurements ( phase ii / iii clinical development program)organ systemparametercriteria , post - baselinedalbavancincomparatorrenalcreatinine1.5 uln and twofold 3 ( 0.2)6 ( 0.6)>uln but normal at baseline*51 ( 3.6)63 ( 6.6)>uln but high at baseline69 ( 46.3)63 ( 52.5)hematologichematocrit0.8 lln and 0.25-fold 5 ( 0.3)4 ( 0.4)platelets0.6 lln and 0.4-fold 2 ( 0.1)4 ( 0.4)wbc0.5 lln and 0.75-fold 1 ( 0.1)1 ( 0.1)hepatic all patientsalttotal17071186 > uln**417 ( 24.4)307 ( 25.9 ) > 3 uln44 ( 2.6)31 ( 2.6 ) > 5 uln9 ( 0.5)9 ( 0.8 ) > 10 uln4 ( 0.2)2 ( 0.2 ) normal baselinealttotal1437975 > uln**218 ( 15.2)139 ( 14.3 ) > 3 uln12 ( 0.8)2 ( 0.2 ) > 5 uln5 ( 0.3)1 ( 0.1 ) > 10 uln3 ( 0.2)0 elevated baselinealttotal237197 > uln**173 ( 73.0)155 ( 78.7 ) > 3 uln30 ( 12.7)28 ( 14.2 ) > 5 uln4 ( 1.7)8 ( 4.1 ) > 10 uln1(0.4)2 ( 1.0 ) alt alanine aminotransferase , lln lower limit of normal , uln upper limit of normal , wbc white blood cell * p = 0.001 , * * p > 0.05 selected laboratory measurements ( phase ii / iii clinical development program ) alt alanine aminotransferase , lln lower limit of normal , uln upper limit of normal , wbc white blood cell * p = 0.001 , * * p > 0.05 of special interest is a comparison of the rate of adverse events in patients receiving the glycopeptide vancomycin and the lipoglycopeptide dalbavancin . the discover studies compared dalbavancin with vancomycin , with an option to switch to oral linezolid to complete 1014 days of total therapy . in these two studies combined , 54 patients who received vancomycin for at least 10 days were compared with 637 who received two doses of intravenous dalbavancin and , to control for any demographic variables associated with continuation of intravenous therapy only , 61 who received dalbavancin and at least 10 days of intravenous placebo ( table 9 ) . fewer teaes ( p = 0.08 ) and serious teaes ( p = 0.03 ) were reported in patients treated with dalbavancin . in an assessment of potential study drug impact on renal function in this population , nephrotoxicity rates were lower in patients receiving dalbavancin than in those receiving vancomycin for at least 10 days [ dalbavancin 3.3 vs. vancomycin 9.3 % ( p = 0.06 ) ] , supported by rates of nephrotoxicity in a smaller subset of patients , controlling for factors related to continuation of intravenous therapy [ dalbavancin 1.7 % vs. vancomycin 9.3 % ( p = 0.21)].table 9summary of total adverse events for patients receiving > 10 days of active or placebo intravenous dosing in discovernumber of patients who experienced at least onedalbavancin ( n = 61)vancomycin ( n = 54 ) p valueteae18 ( 29.5)25 ( 46.3)0.08teae leading to premature discontinuation of study drug1 ( 1.6)01.0drug - related teae3 ( 4.9)3 ( 5.6)1.00serious teae1 ( 1.6)7 ( 13.0)0.03serious teae leading to premature study drug discontinuation001.0drug - related serious teae001.0serious teae leading to death01 ( 1.9)0.23nephrotoxicity on therapy safety population21/637 ( 3.3)31/638 ( 4.9)0.16 all dalbavancin patients versus iv vancomycin only21/637 ( 3.3)5/54 ( 9.3)0.06 patients who received only iv therapy and no oral therapy 1/58 ( 1.7)5/54 ( 9.3)0.21data are presented as n ( % ) unless otherwise indicated iv intravenous , teae treatment - emergent adverse event nephrotoxicity defined as a 50 % increase from baseline serum creatinine or an absolute increase in serum creatinine of 0.5 mg / dl ; p value by fischer s exact test dalbavancin - active ( and iv vancomycin - placebo ) versus iv vancomycin - active ( and dalbavancin - placebo ) without receiving oral linezolid / placebo summary of total adverse events for patients receiving > 10 days of active or placebo intravenous dosing in discover data are presented as n ( % ) unless otherwise indicated iv intravenous , teae treatment - emergent adverse event nephrotoxicity defined as a 50 % increase from baseline serum creatinine or an absolute increase in serum creatinine of 0.5 mg / dl ; p value by fischer s exact test dalbavancin - active ( and iv vancomycin - placebo ) versus iv vancomycin - active ( and dalbavancin - placebo ) without receiving oral linezolid / placebo the safety of dalbavancin has been assessed in 14 clinical studies , including seven phase ii or phase iii studies of skin infection . the adverse event profile of dalbavancin has been rigorously studied in these clinical trials , leading to the regulatory approval for the indication of absssi in the usa and the eu . with a database of 1778 patients receiving dalbavancin , it is possible to exclude with 95 % confidence the occurrence of any as yet unobserved adverse event at an incidence of > 0.2 % , providing reassurance that the data collected thus far will be useful in informing the benefit / risk assessment of dalbavancin . further refinements of the safety profile will follow with the addition of new clinical trial data and a rigorous post - marketing surveillance program . the rate of adverse events for patients treated with dalbavancin was similar or slightly lower relative to a pool of comparator agents that included cephalosporins , vancomycin , oxacillin , nafcillin , and linezolid , whether from any cause or related to drug , based on the investigator s assessment of causality . the types of treatment - related adverse events observed are those commonly seen in patients enrolled in clinical trials , including nausea , diarrhea , and pruritus . while a reduction in adverse event rates of 23 % may be of limited clinical significance to the treatment decision for an individual patient , it may be more meaningful on a population basis and , at a minimum , provide some reassurance that dalbavancin is safe and well tolerated relative to alternative treatment options . one concern that could be raised regarding any drug with a long half - life is that adverse events , when they occur , could last longer , be more severe and possibly occur later , than would occur with a drug with a short half - life . however , patients treated with dalbavancin had a mean duration of adverse events that was similar to that of the much shorter - acting comparators , and these events did not occur any later post - baseline than did events occurring with the comparator , even though follow - up visits occurred up to 70 days after the last scheduled visit . no difference in the adverse event profile was seen when patients were assessed by age , sex , or race . no difference was also seen in the rate of either renal- or hepatic - associated adverse events . fewer patients treated with dalbavancin had an elevation in creatinine assessed either against the pooled comparators or against vancomycin , specifically . increases in serum levels of liver enzymes [ alt , aspartate transaminase ( ast ) ] , associated with microscopic findings ( histiocytic vacuolation and focal hepatocyte necrosis ) in the liver , were noted in toxicology studies in rats and dogs when dalbavancin was administered daily for 2890 days . in addition , renal toxicity characterized by increases in blood urea nitrogen ( bun ) and creatinine and microscopic kidney findings was observed in rats and dogs at doses 57 times higher than the expected human dose on an exposure basis . in the clinical program , the majority of the patients with elevated transaminases were found to have other underlying conditions associated with a higher likelihood of hepatic transaminase elevations , even with a normal alt at baseline , and , overall , they occurred at similar rates with dalbavancin and the comparator . presentations of pooled safety data prior to marketing authorization are only the first step in the collection of important safety information . safety data collected from the post - marketing experience will ultimately contribute significantly to our understanding of safety and tolerability , both because the drug is now used in more typical and less controlled circumstances than seen in a clinical trial and because the number of patients exposed to the drug will increase dramatically . it should be noted that one phase ii study and one phase iii study have not been previously published but are included in the safety assessments for completeness ; both studies were performed in patients with skin infections , and the safety outcomes within each trial were similar to the overall experience ( data on file , allergan plc . ) . the presentation of these safety data could have been alternatively displayed as relative risk with controls for heterogeneity , given that the patients were enrolled in many studies , not one large trial . however , ultimately , given that the patients were selected for entry into the studies with many criteria common to each trial , data were collected via a standardized data - collection instrument and statistical analyses performed through one set of programs , the overall interpretation of outcomes would not be materially different if analyzed with a different approach . lastly , it should also be pointed out that approximately 20 % of patients in this pooled analysis had an uncomplicated skin infection and received a single dose of dalbavancin 1000 mg . though they did not receive a total dose of dalbavancin 1500 mg , they had a significant duration of exposure to drug over the observation period given the compound s long half - life , and including the outcomes from these patients provides greater precision for our estimates of any late adverse sequelae . relative to other options for treatment of gram - positive infections of the skin , dalbavancin was safe and well tolerated in an extensive clinical trial database of patients with skin and skin structure infection . collection and analysis of post - marketing surveillance data will help further refine this favorable overall safety profile . george h. talbot reports receiving fees through talbot advisors llc for serving on advisory boards and consulting for durata therapeutics and owning stock or stock options for durata therapeutics . mark wilcox reports receiving consulting fees from astra - zeneca , bayer , cerexa , durata , the medicines company , motif biosciences , nabriva , paratek and pfizer ; lecture fees from astra - zeneca and pfizer ; and grant support from pfizer . sailaja puttagunta and michael w. dunne report being employees of and owning stock in durata therapeutics .

introductiondalbavancin is a new lipoglycopeptide that is active against gram - positive pathogens , including methicillin - resistant staphylococcus aureus . it has a half - life of 14.4 days , permitting intravenous treatment of acute bacterial skin and skin structure infections without the need for daily dosing.objectivethe objective of these analyses was to compare the adverse event profile of dalbavancin with that of the comparator agents in the treatment of skin and skin structure infections.methodsdata on adverse events and laboratory assessments collected from 3002 patients enrolled in seven late - stage , randomized clinical trials were analyzed for patients receiving dalbavancin or a comparator antibiotic.resultsoverall adverse event rates were similar or lower for patients receiving dalbavancin ( 799/1778 ; 44.9 % ) compared with those receiving comparator agents ( 573/1224 ; 46.8 % , p = 0.012 ) . the most common treatment - emergent adverse events were nausea , headache , diarrhea , constipation , vomiting , rash , urinary tract infection , pruritus , and insomnia . the duration and timing of the onset of adverse events were similar for patients receiving dalbavancin relative to the comparators.conclusiondalbavancin exhibits a favorable overall safety profile for treatment of acute bacterial skin and skin structure infections due to gram - positive bacteria .

raw materials used to form the glass - ceramics were over 99.9% purity in sio2 , caco3 , cahpo42h2o , h3po4 , mgo , and caf2 , and 200 g of the composition of cao 44.9 weight percent ( wt% ) , sio2 34.2 wt% , p2o5 16.3 wt% , mgo 4.6 wt% , and caf2 0.5 wt% were batched . the batched sample underwent ball milling for 24 hours with absolute methanol as a solvent and was dried . after drying in the mixer , each batch was placed in a platinum crucible and melted at 1,500-1,600 for two hours . the glass - ceramic was manufactured through rapid cooling by pouring the material into a water bath and grounding the contents using spex milling for 15 hours to make around 1 - 2 m sized glass powders . as a result in addition , high purity caco3 ( 99.99% , kojundo chemical co. , ltd , sakado - shi , japan ) , sio2 ( 99.9% , kojundo chemical co. , ltd , sakado - shi , japan ) and b2o3 ( 99.9% , kojundo chemical co. , ltd , sakado - shi , japan ) were used , and the composition of cao 45.7% , sio2 45.7% and b2o3 8.6% in the mole ratio was named as cs10b . the ratios of a - w gc and cs10b were 1:4 , 1:9 and 1:19 in p20b80 , p10b90 , and p5b95 , respectively and the composition was cao 45.54 wt% , sio2 43.40 wt% , p2o5 3.26 wt% , b2o3 8.00 wt% , mgo 0.92 wt% and caf2 0.10 wt% in p20b80 and cao 43.57 wt% , sio2 45.30 wt% , p2o5 1.62 wt% , b2o3 9.00 wt% , mgo 0.46 wt% and caf2 0.05 wt% in p20b90 and cao 43.51 wt% , sio2 45.92 wt% , p2o5 0.81 wt% , b2o3 9.50 wt% , mgo 0.23 wt% and caf2 0.025 wt% in p5b95 . p20b80 , p10b90 , and p5b95 were maintained at 1,450 for two hours , and glass powders were produced by melting and cooling them rapidly . sponge infiltration slurry was used to manufacture a sponge - type porous implant by mixing polyvinyl alcohol and the glass powders . the slurry was infiltrated three times by using 10 g of four appropriate - sized sponges ( 4 5 cm ) once each time . after making both the inner and outer parts infiltrated evenly , blocked pores were pierced with an air gun before the infiltration solution dried . the glass - ceramics manufactured through this method were dried by open air , and sponges were burnt at 600 to make sponge - type porous implants . fifty - one new zealand white male rabbits with an average weight of 3.3 0.3 kg were kept individually in standard cages under 12 hours on / off light cycles . room temperature and humidity all animals were divided into four groups by implant materials , i.e. , p20b80 ( 18 rabbits ) , p10b90 ( 16 rabbits ) , p5b95 ( 9 rabbits ) , with added autografts ( 8 rabbits ) . the study was approved by the institutional animal care and use committee at the clinical research institute seoul national university hospital . care was taken to avoid unnecessary stress and discomfort to the animals throughout the experimental period . surgical procedures were performed to the lumbar vertebra ( l5-l6 ) on both sides of intertransverse processes under general anesthesia as described by boden et al.13 ) three milliliters of glass - ceramics were implanted on each side of the intertransverse processes . this procedure was described in our previous reports.11,12 ) after the placement of the glass - ceramics , fascial tissue layers were repositioned and sutured after irrigation . manual palpation to determine the fusion status was performed by stressing across the fusion site . formation of hca on the surface of the specimens was observed by scanning electron microscopy ( jsm5600 , jeol , akishima , japan ) . immediately after euthanasia , fusion success was evaluated by holding the upper and lower transverse processes of the 5th and 6th vertebrae . twisting , bending , and folding motions were performed . only specimens with immobility against the applied forces were judged to be successful fusions.11,12 ) before tensile testing , all remaining muscle and ligaments including the intervertebral discs , posterior longitudinal ligaments , and the thecal sac were removed . holes were made in the l5 and l6 vertebral bodies with a 3.2-mm - diameter drill bit , and then a 3.0-mm - diameter steel rod was inserted.11,12 ) an instron electromechanical materials testing system ( instron 5582 , instron co. , norwood , ma , usa ) was used to test the l5 and l6 uniaxial tensile forces at a displacement rate of 0.5 cm per minute11,12 ) after fitting with a calibrated load - cell of 10 n. the ultimate tensile load , i.e. , the break point , was read from the peak load to failure in the load - displacement curve . a posteroanterior radiograph was completed for each animal immediately postsurgery at 45 kv for 12 milliseconds.11,12 ) additional plain radiographs were obtained for all surviving animals at 2 , 4 , 6 , 8 , 10 , 12 weeks postsurgery . we examined whether clear opacity in the border of blocks of each implant immediate postsurgery became vague compared to adjacent areas , whether clear radioopacity among blocks presurgery became similar with that of neighboring blocks , and whether fusion mass connecting adjacent transverse processes was formed . we calculated the degradation rate of the glass - ceramics radiomorphometrically by comparing changes in the area occupied by the glass - ceramics between the initial and final radiographs which was described in previous reports.11,12 ) the percentage of the area of glass - ceramics was evaluated in the final radiographs ( fig . histological sections were carried out in the same way as reported in previous studies.11,12 ) lumbar spines from each group were fixed for 24 hours in 10% formalin . a sagittal section from the right and left sides undecalcified tissues were embedded in methacrylate and sectioned 4 m in width parallel to the fusion mass with a diamond cutter ( exakt300cp , exakt co. , norderstedt , germany).13 ) slides were stained using hematoxylin and eosin . satisfactory osteoconductivity was defined as new bone was detected in pores or adjacent to the ceramics . the degree and the pattern of bony fusion between bone and implant and the surface change of the fusion mass were observed with a light microscope . moreover , the degree of bone growth was evaluated by classifying parts of the fusion mass into an implant , new bone , and soft tissues . null hypotheses of no difference were rejected if p - values were less than 0.05 . raw materials used to form the glass - ceramics were over 99.9% purity in sio2 , caco3 , cahpo42h2o , h3po4 , mgo , and caf2 , and 200 g of the composition of cao 44.9 weight percent ( wt% ) , sio2 34.2 wt% , p2o5 16.3 wt% , mgo 4.6 wt% , and caf2 0.5 wt% were batched . the batched sample underwent ball milling for 24 hours with absolute methanol as a solvent and was dried . after drying in the mixer , each batch was placed in a platinum crucible and melted at 1,500-1,600 for two hours . the glass - ceramic was manufactured through rapid cooling by pouring the material into a water bath and grounding the contents using spex milling for 15 hours to make around 1 - 2 m sized glass powders . as a result in addition , high purity caco3 ( 99.99% , kojundo chemical co. , ltd , sakado - shi , japan ) , sio2 ( 99.9% , kojundo chemical co. , ltd , sakado - shi , japan ) and b2o3 ( 99.9% , kojundo chemical co. , ltd , sakado - shi , japan ) were used , and the composition of cao 45.7% , sio2 45.7% and b2o3 8.6% in the mole ratio was named as cs10b . the ratios of a - w gc and cs10b were 1:4 , 1:9 and 1:19 in p20b80 , p10b90 , and p5b95 , respectively and the composition was cao 45.54 wt% , sio2 43.40 wt% , p2o5 3.26 wt% , b2o3 8.00 wt% , mgo 0.92 wt% and caf2 0.10 wt% in p20b80 and cao 43.57 wt% , sio2 45.30 wt% , p2o5 1.62 wt% , b2o3 9.00 wt% , mgo 0.46 wt% and caf2 0.05 wt% in p20b90 and cao 43.51 wt% , sio2 45.92 wt% , p2o5 0.81 wt% , b2o3 9.50 wt% , mgo 0.23 wt% and caf2 0.025 wt% in p5b95 . p20b80 , p10b90 , and p5b95 were maintained at 1,450 for two hours , and glass powders were produced by melting and cooling them rapidly . sponge infiltration slurry was used to manufacture a sponge - type porous implant by mixing polyvinyl alcohol and the glass powders . the slurry was infiltrated three times by using 10 g of four appropriate - sized sponges ( 4 5 cm ) once each time . after making both the inner and outer parts infiltrated evenly , blocked pores were pierced with an air gun before the infiltration solution dried . the glass - ceramics manufactured through this method were dried by open air , and sponges were burnt at 600 to make sponge - type porous implants . fifty - one new zealand white male rabbits with an average weight of 3.3 0.3 kg were kept individually in standard cages under 12 hours on / off light cycles . room temperature and humidity all animals were divided into four groups by implant materials , i.e. , p20b80 ( 18 rabbits ) , p10b90 ( 16 rabbits ) , p5b95 ( 9 rabbits ) , with added autografts ( 8 rabbits ) . the study was approved by the institutional animal care and use committee at the clinical research institute seoul national university hospital . care was taken to avoid unnecessary stress and discomfort to the animals throughout the experimental period . surgical procedures were performed to the lumbar vertebra ( l5-l6 ) on both sides of intertransverse processes under general anesthesia as described by boden et al.13 ) three milliliters of glass - ceramics were implanted on each side of the intertransverse processes . this procedure was described in our previous reports.11,12 ) after the placement of the glass - ceramics , fascial tissue layers were repositioned and sutured after irrigation . manual palpation to determine the fusion status was performed by stressing across the fusion site . formation of hca on the surface of the specimens was observed by scanning electron microscopy ( jsm5600 , jeol , akishima , japan ) . immediately after euthanasia , fusion success was evaluated by holding the upper and lower transverse processes of the 5th and 6th vertebrae . twisting , bending , and folding motions were performed . only specimens with immobility against the applied forces before tensile testing , all remaining muscle and ligaments including the intervertebral discs , posterior longitudinal ligaments , and the thecal sac were removed . holes were made in the l5 and l6 vertebral bodies with a 3.2-mm - diameter drill bit , and then a 3.0-mm - diameter steel rod was inserted.11,12 ) an instron electromechanical materials testing system ( instron 5582 , instron co. , norwood , ma , usa ) was used to test the l5 and l6 uniaxial tensile forces at a displacement rate of 0.5 cm per minute11,12 ) after fitting with a calibrated load - cell of 10 n. the ultimate tensile load , i.e. , the break point , was read from the peak load to failure in the load - displacement curve . a posteroanterior radiograph was completed for each animal immediately postsurgery at 45 kv for 12 milliseconds.11,12 ) additional plain radiographs were obtained for all surviving animals at 2 , 4 , 6 , 8 , 10 , 12 weeks postsurgery . we examined whether clear opacity in the border of blocks of each implant immediate postsurgery became vague compared to adjacent areas , whether clear radioopacity among blocks presurgery became similar with that of neighboring blocks , and whether fusion mass connecting adjacent transverse processes was formed . we calculated the degradation rate of the glass - ceramics radiomorphometrically by comparing changes in the area occupied by the glass - ceramics between the initial and final radiographs which was described in previous reports.11,12 ) the percentage of the area of glass - ceramics was evaluated in the final radiographs ( fig . histological sections were carried out in the same way as reported in previous studies.11,12 ) lumbar spines from each group were fixed for 24 hours in 10% formalin . a sagittal section from the right and left sides was taken for processing and evaluated separately . undecalcified tissues were embedded in methacrylate and sectioned 4 m in width parallel to the fusion mass with a diamond cutter ( exakt300cp , exakt co. , norderstedt , germany).13 ) slides were stained using hematoxylin and eosin . satisfactory osteoconductivity was defined as new bone was detected in pores or adjacent to the ceramics . the degree and the pattern of bony fusion between bone and implant and the surface change of the fusion mass were observed with a light microscope . moreover , the degree of bone growth was evaluated by classifying parts of the fusion mass into an implant , new bone , and soft tissues . null hypotheses of no difference were rejected if p - values were less than 0.05 . of the fifty - one rabbit specimens initially used in this study , eight experimental animals were lost immediately after surgery and during the healing phase . four groups were designated according to the implanted material or autograft and the number of specimens were evaluated per group . group names and their numbers are as follows : p20b80 group , 17 specimens ; p10b90 group , 11 specimens ; p5b95 group , 7 specimens ; and the autograft group , 8 specimens . after soaking in sbf for 1 day , an hca layer covered the whole surface of 25% of the specimens in the p20b80 group . however , an hca layer appeared 3 days after soaking in sbf in the p10b90 group and 5 days after soaking in sbf for the p5b95 group . moreover , the aggregate of the hca layer for groups p10b90 and p5b95 was smaller in comparison with that of the p20b80 group ( fig . solid bone fusion was detected in 5 of 17 specimens ( 29.4% ) in the p20b80 group , 0 of 11 ( 0.0% ) in the p10b90 group , 1 of 7 ( 14.3% ) in the p5b95 group , and 8 of 8 ( 100.0% ) in the autograft group . the autograft group recorded significantly higher fusion rates than all the implanted materials groups of p20b80 , p10b90 , and p5b95 ( p < 0.0001 , 0.0016 and 0.0014 , respectively ) . the fusion rate for the p20b80 group was higher than those of the p10b90 and p5b95 groups . the uniaxial tensile test showed 214.9 46.8 n of the ultimate tensile load for the p20b80 group , 187.1 44.9 n in the p10b90 group , and 230.3 13.9 n in the p5b95 group . the ultimate tensile load of the control group , i.e. , the autograft , was slightly higher than those of the other groups although there was no significant difference . the degree of resorption increased at 12 weeks compared to that immediately postsurgery in the implanted material p20b80 , p10b90 , and p5b95 groups , and the implants formed one mass ( fig . 3 ) . in addition , the radio - opaque area was inside the fusion mass , and it was , therefore , considered that new bone grew into it and bony fusion was in the process . the proportions of the area occupied by the glass - ceramics at the final radiographs to the area occupied by the glass - ceramics at the initial radiographs were 76.6% 7.0% in the p20b80 group , 74.2% 9.0% in the p10b90 group , and 75.8% 5.8% in the p5b95 group . the radiomorphometry of the three kinds of cao - sio2-p2o5-b2o3 glass - ceramic areas revealed no statistical difference with time . according to the histological study , satisfactory osteoconductivity was found in all of the three types of cao - sio2-p2o5-b2o3 glass - ceramics . in the p20b80 , p10b90 , and p5b95 groups , new bone was formed around the ceramics inserted between the upper and lower transverse processes continuously . undecalcified examination revealed that the glass - ceramic implants had very low opacity , and the brown ceramic implant was absorbed losing nearly all its original pattern . new bone had osteoblasts and osteocytes in the adjacent and central areas , respectively , and the formation of lamellar bone was observed with both osteocytes arranged to be in concentric circles and mature bone matrices ( fig . the border of the composite plane between implants and bone became vague when the implants were absorbed . it is assumed that the glass - ceramics were absorbed during the formation of bone tissues on the ceramic implants , and the absorption occurred mainly in areas in contact with bone . after soaking in sbf for 1 day , an hca layer covered the whole surface of 25% of the specimens in the p20b80 group . however , an hca layer appeared 3 days after soaking in sbf in the p10b90 group and 5 days after soaking in sbf for the p5b95 group . moreover , the aggregate of the hca layer for groups p10b90 and p5b95 was smaller in comparison with that of the p20b80 group ( fig . based on manual palpation , solid bone fusion was detected in 5 of 17 specimens ( 29.4% ) in the p20b80 group , 0 of 11 ( 0.0% ) in the p10b90 group , 1 of 7 ( 14.3% ) in the p5b95 group , and 8 of 8 ( 100.0% ) in the autograft group . the autograft group recorded significantly higher fusion rates than all the implanted materials groups of p20b80 , p10b90 , and p5b95 ( p < 0.0001 , 0.0016 and 0.0014 , respectively ) . the fusion rate for the p20b80 group was higher than those of the p10b90 and p5b95 groups . however , the difference was statistically insignificant . the uniaxial tensile test showed 214.9 46.8 n of the ultimate tensile load for the p20b80 group , 187.1 44.9 n in the p10b90 group , and 230.3 13.9 n in the p5b95 group . the ultimate tensile load of the control group , i.e. , the autograft , was slightly higher than those of the other groups although there was no significant difference . the degree of resorption increased at 12 weeks compared to that immediately postsurgery in the implanted material p20b80 , p10b90 , and p5b95 groups , and the implants formed one mass ( fig . 3 ) . in addition , the radio - opaque area was inside the fusion mass , and it was , therefore , considered that new bone grew into it and bony fusion was in the process . the proportions of the area occupied by the glass - ceramics at the final radiographs to the area occupied by the glass - ceramics at the initial radiographs were 76.6% 7.0% in the p20b80 group , 74.2% 9.0% in the p10b90 group , and 75.8% 5.8% in the p5b95 group . the radiomorphometry of the three kinds of cao - sio2-p2o5-b2o3 glass - ceramic areas revealed no statistical difference with time . according to the histological study , satisfactory osteoconductivity was found in all of the three types of cao - sio2-p2o5-b2o3 glass - ceramics . in the p20b80 , p10b90 , and p5b95 groups , new bone was formed around the ceramics inserted between the upper and lower transverse processes continuously . undecalcified examination revealed that the glass - ceramic implants had very low opacity , and the brown ceramic implant was absorbed losing nearly all its original pattern . new bone had osteoblasts and osteocytes in the adjacent and central areas , respectively , and the formation of lamellar bone was observed with both osteocytes arranged to be in concentric circles and mature bone matrices ( fig . the border of the composite plane between implants and bone became vague when the implants were absorbed . it is assumed that the glass - ceramics were absorbed during the formation of bone tissues on the ceramic implants , and the absorption occurred mainly in areas in contact with bone . hydroxyapatite is clinically applied in cases of bone defects and spinal fusion.13 - 15 ) however , its resorbing properties and mechanical strength are considered relatively low . although calcium phosphate ceramics with tricalcium phosphate are known to have high resorbing properties,16 ) their low mechanical strengths have been commented as a distinct disadvantage . because bioactive glass - ceramics can control resorption and mechanical strength according to their composition , this study also tried to regulate their resorbing properties with b2o3 content . the correlation that a higher b2o3 content leads to higher resorption was displayed in our previous study . in the in vitro study using sbf , p20b80 ( p2o5 3.26 wt% ) formed an hca layer after soaking for 1 day , while p10b90 ( p2o5 1.62 wt% ) and p5b95 ( p2o5 0.81 wt% ) , with their relatively low p2o5 contents , began to form a layer in proportion to the p2o5 content and its amount was also proportional to the p2o5 content . however , the difference in the amount of the hca layer produced after five days was not significantly different between the two compounds . the difference in the time in forming the hca layer was notably considered to be attributed to the p2o5 content of each glass - ceramic . although p2o5 is inessential for the nucleation of hca , it can earlier increase the amount of the hca layer as it accelerates hca formation . with regards to this point , decreased p2o5 content could influence osteoconductivity . for these reasons , the increased b2o3 and decreased p2o5 content that were used to improve the resorption of the glass - ceramics was considered to decline eventually in fusion rates as displayed in the in vivo study . this study measured the two - dimensional area of the implanted glass - ceramics in radiographic images to assess their resorption . because the connection of trabecular bone found in complete fusions was unclear in groups p20b80 , p10b90 , and p5b95 , the autograft group was found to have bony bridging in the upper and lower transverse processes at 12 weeks ; and , thus , solid bony fusion formed . the rate of the absorbed area was only around 25% and , thus , it was considered an inadequate resorption rate . when observing the measured border of the radioopaque lesions , the implanted glass - ceramic material remained as debris after the area of the absorption of the porous structure became radio - opaque . gross inspection of the glass - ceramics implants revealed that the porous structure was nearly lost , and the absorption of the glass - ceramics used in this study was much higher than that in previous studies . in our previous study , the fusion rate of compositions with relatively higher p2o5 rates and a - w gc was 80%-90%.11 ) for this study , the fusion rate of p20b80 with the highest level of p2o5 was recorded as only 29.4% , and most of the p10b90 and p5b95 groups showed pseudarthrosis . conversely , the histological examination showed excellent osteoconductivity found in all three glass - ceramics . in other words , newly formed bony tissues were bonded directly to the implanted glass - ceramics and remodeling also proceeded . thus , it is believed that the decreased p2o5 content affected osteoconductivity to some degree . therefore , a higher b2o3 content , rather than osteoconductivity itself , led to poorer early porous structures for increased resorption and was considered to be a major cause of pseudarthrosis . in general , for bone defect filling , stem cells are supplied in neighboring parts of the implanted glass - ceramics , and the vascular structure grows into it easily . thus , this resorption characteristic is considered to be highly advantageous . in the case of intertransverse process fusions , because the transverse processes mainly consist of cortical bone with very small amounts of stem cells and the distance between transverse processes is relatively long , some parts close to the bone can form new bone by receiving stem cells . however , the middle area between the transverse processes is difficult to attain fusion as this area needs the connection of new bones produced from both transverse processes . therefore , to obtain intertransverse process fusion , porous structures and osteoconductivity of the osteoconductive scaffolds should be maintained sufficiently during the period needed for newly formed bone to grow and be connected in neighboring areas . for intertransverse process fusion with regards to this study , the three types of glass - ceramics used had excellent osteoconductivity but could not maintain the porous structure fully to prevent pseudarthrosis . properties of the ideal biodegradable material include : ( 1 ) the ability to maintain strength and stability of porous structures during degradation until achieving fusion in the early stage , ( 2 ) the ability to be replaced completely into the new bone , ( 3 ) and having adequate reconciling resorption and new bone formation rates . however , materials meeting all of these conditions have yet to be invented . for one reason , the absorption of porous glass - ceramics is performed through a slow degradation of the debris made by the destruction of the porous structure rather than by the maintenance of the porous structure , which is critical for osteoconductivity . unfortunately , the destruction of a porous structure actually negatively influences various aspects of osteoconductivity . moreover , the environment for bone formation in the implanted area varies according to anatomical location . however , even when implants are made in the same anatomical location , large differences in time and success rates of bone formation can depend on age and the health condition of the recipients . therefore , in a favorable environment for bone formation , glass - ceramics with high absorption rates can produce an ideal situation , obtaining not only bony fusion but also absorption . conversely , the same glass - ceramics in an unfavorable environment for bone formation can experience pseudarthrosis due to absorption taking place before new bone formation can occur . from all of these results , osteoconductivity and sufficient porous structure maintaining properties rather than resorbing properties are considered to be more advantageous for bony fusion in an environment unfavorable for new bone formation . furthermore , resorption rates faster than new bone formation growth rates need careful attention as an imbalance may lead to failure . however , in cases using bone morphogenetic protein with high osteoinductivity and stem cells with properties of both osteoinductivity and osteogenesis , osteoconductive bio glass - ceramics with high resorbing properties are expected to be used as carriers . in conclusion , the high resorbing properties of osteoconductive porous glass - ceramics have a material advantage of completely dissolving within the human body . however , their ability to be rapidly resorbed before bony fusion in their role as osteoconductive scaffolds is a disadvantage that must be taken into consideration .

backgroundbioactive glass - ceramics have the ability to directly bind to bones and have been widely used as bone graft substitutes due to their high osteoconductivity and biocompatibility . cao - sio2-p2o5-b2o3 glass - ceramics are known to have good osteoconductivity and are used as bone graft extenders.methodsthis study aimed to evaluate the effects of the resorbing properties of glass - ceramics in bone fusion after producing and analyzing three types of cao - sio2-p2o5-b2o3 glass - ceramics with high osteoconductivity that had enhanced resorption by having an increased b2o3 content . the three types of cao - sio2-p2o5-b2o3 glass - ceramics with b2o3 contents of 8.0 , 9.0 , and 9.5 weight % were designated and grouped as p20b80 , p10b90 , and p5b95 , respectively . glass - ceramic types were tested for fusion rates and bone formation by employing the lumbar 5 - 6 intertransverse process fusion model in 51 new zealand male rabbits . bioactivity was assessed by soaking in simulated body fluid ( sbf).resultsin vitro study results showed sufficient hydroxycarbonate apatite layer formation occurred for p20b80 in1 day , for p10b90 in 3 days , and for p5b95 in 5 days after soaking in sbf . for the rabbit lumbar spine posterolateral fusion model , the autograft group recorded a 100% fusion rate with levels significantly higher than those of p20b80 ( 29.4% ) , p10b90 ( 0% ) , and p5b95 ( 14.3% ) , with high resorbing properties . resorbing property differences among the three glass - ceramic groups were not significant . histological results showed new bone formation confirming osteoconductivity in all three types of glass - ceramics . radiomorphometric results also confirmed the resorbing properties of the three glass - ceramic types.conclusionsthe high resorbing properties and osteoconductivity of porous glass - ceramics can be advantageous as no glass - ceramics remain in the body . however , their relatively fast rate of resorption in the body negatively affects their role as an osteoconductive scaffold as glass - ceramics are resorbed before bony fusion .

the problem of biological aging has attracted much attention in recent years . based on the data of human demography and experiments of other living organisms , many important phenomena of longevity have been found @xcite . for instance , the gompertz law was observed for intermediate ages , that is , the mortality function increases exponentially with age , while at old ages the mortality was found to decelerate or level off , and even decline for some organisms like flies , worms , and yeast @xcite . to reproduce and explain these phenomena , various models of senescence have been proposed , with genetic or nongenetic mechanisms @xcite . among them , the one widely used by physicists is the penna model @xcite , where one computer word is used to represent the inherited genome of one individual and each bit of the word corresponds to one age of the individual lifetime . a bit set to one represents a deleterious mutation and the suffering from an inherited disease from this age on , and the individual will die if the accumulation of these set bits exceeds a threshold . although the penna model has been well applied to many problems related to biological aging @xcite , there exists an important flaw in this model as pointed out by pletcher and neuhauser very recently @xcite . that is , the model predicts that for a genetically identical population all individuals have their genetic death at the same age , but this is inconsistent with the experimental results @xcite which also exhibited the exponential gompertz law and the deceleration of the old age mortality for the genetically homogeneous case . thus , a more complicated model has been proposed @xcite . in this paper we develop a simpler stochastic model bridging the gap between the standard ( deterministic ) penna model and the pletcher - neuhauser approach . the simulations and analytic results of this model are shown to agree with some features of the biological aging , e.g. , the exponential increase of the mortality function and the deceleration at advanced ages , and the flaw of the penna model mentioned above can be avoided . as in the standard penna model , here the genome of each individual is characterized by a string ( computer word ) of 32 bits , and each bit is expressed as a particular age in the life of the individual . a bit @xmath0 is set to @xmath1 if it represents a deleterious mutation , and from this age @xmath0 on this bit will continuously affect the survival probability of the individual . that is , at age @xmath2 ( @xmath3 ) the death probability contributed by the mutated bit @xmath0 is @xmath4 , with the corresponding survival probability @xmath5 . otherwise , this bit is set to zero and has no effect on death . thus our assumptions are very different from an earlier `` fermi '' function in another stochastic penna model @xcite . the individual s survival probability @xmath6 up to age @xmath2 is the product of the contributions from all the bits before @xmath2 : @xmath7 where @xmath8 or @xmath9 ( @xmath10 ) represents the @xmath0th bit . with the form of @xmath4 , one can obtain the mortality function by simulation or analytical work . in this work we simply assume that @xmath11 with the constant @xmath12 and the limit @xmath13 , which means that the contribution of death probability from bit @xmath0 ( if set to @xmath1 ) is assumed to increase linearly with the age . the other forms of @xmath4 , such as the exponential and the square root forms , have been tried , and we have also simulated the other probabilistic penna model with fermi function @xcite . although some phenomena for the genetically heterogeneous steady - state population can be reproduced , they can not give a good result for the genetically homogeneous populations . the alive individual will generate @xmath14 offsprings from the minimum reproduction age @xmath15 to the maximum one @xmath16 , and the genome of each offspring is the same as the parent one , except for @xmath17 mutations randomly occurring at birth . at each time step @xmath18 , a verhulst factor @xmath19 denoting the survival probability of the individual due to the space and food restrictions is introduced , where @xmath20 is the current population size and @xmath21 is the carrying capacity of the environment , usually set to @xmath22 . in the next section [ sec3 ] the simulations based on these rules are presented , while for genetically identical individuals , which have the same genotype randomly sampled from the simulated steady - state population , the analytic results can be derived , as shown in section [ sec4 ] . moreover , in this paper the mortality function @xmath23 at age @xmath2 is defined as @xmath24 where @xmath25 denotes the number of alive individuals with age @xmath2 , and @xmath26 is the survival rate . to eliminate the effect of the verhulst factor , the normalized mortality function is preferred @xcite , i.e. , @xmath27 . \label{mortfunc}\ ] ] in our simulations , initially the population size @xmath28 is @xmath29 and all bits of all the strings are set to zero , i.e. , free of mutations . one time step @xmath18 corresponds to one aging interval of the individuals , or reading one bit of all strings . the reproduction range is set from @xmath30 to @xmath31 with the birth rate @xmath32 , and the results are similar if using the maximum value of @xmath33 . @xmath34 mutation for each offspring genome is introduced at birth , and here only the bad mutations are taken into account , that is , the bit randomly selected for mutation is always set to @xmath1 . ( the good mutations have also been considered , e.g. , 10% good mutations and 90% bad ones , and similar results are found . ) [ fig - pop - mut ] shows the evolution of the whole population size @xmath20 until @xmath35 . similar to the standard penna model , the steady - state population is obtained at late timesteps , and as a result of evolution and selection , the frequency of deleterious bits ( set as @xmath1 ) for the individual of the steady - state population is low at early ages ( especially before the reproduction age ) and very high at old ones . this behavior of the frequency ( or the bad mutation rate ) is shown in the inset of fig . [ fig - pop - mut ] . the mortality function is calculated using eq . ( [ mortfunc ] ) and averaged over the steady - state population from timesteps 5000 to 10000 , as shown in fig . [ fig - mortality ] . the result is consistent with the experimental and empirical observations @xcite , that is , at intermediate ages the mortality function increases exponentially , exhibiting the gompertz law , and deceleration occurs for old ages . for comparison , the mortality simulated by the standard ( deterministic ) penna model is also shown in fig . [ fig - mortality ] , with the threshold of the accumulated bad mutations @xmath36 and the other parameters unchanged . the exponential gompertz law can also be obtained for the standard penna model @xcite , however , no deceleration is observed except for suitable modifications summarized in @xcite ; see also @xcite . to study the genetically homogeneous population , one can randomly sample an individual ( genotype ) from the simulated steady - state population , and then `` clone '' it to create the whole genetically identical population . according to the form of these bit - strings , the mortality function can be derived and calculated analytically . as in some experiments of fruit flies @xcite , reproduction is prevented during the aging of genetically homogeneous individuals . thus , for this population of single genotype , we have @xmath37 where @xmath25 , @xmath38 , is the number of individuals with age @xmath2 in the population , and the function @xmath39 is defined by eq . ( [ liveprob ] ) . then the survival rate is easily obtained : @xmath40 for the mortality function , the normalized formula ( [ mortfunc ] ) is used to be consistent with the simulations in sec . [ sec3 ] , and then we have @xmath41 . \label{hommort}\ ] ] different genotypes have been selected randomly from the stable population of sec . [ sec3 ] , and the corresponding mortality function of each type is calculated using eq . ( [ hommort ] ) . some examples are shown in fig . [ fig - clonemort ] for linear - log plots , where part of them obey the exponential gompertz law at the intermediate ages , similar to that of the above simulation ( sec . [ sec3 ] ) and experiments @xcite . moreover , all of these curves exhibit the deceleration for old ages . moreover , the analytic calculation is also available if the reproduction is allowed as in other experiments of genetically identical population , but for the case of no mutation . the details are shown in the appendix , and the mortality function derived is the same as eq . ( [ hommort ] ) . in this paper a stochastic genetic model of aging is developed based on the bit - string asexual penna model , and the results of the exponentially increasing mortality at intermediate ages and its deceleration at old ages are obtained for both the genetically heterogeneous steady - state population and the homogeneous individuals . however , the decrease of mortality for the oldest ages , observed in some experiments @xcite , can not be described by the mechanism of this model . although the properties for intermediate and old ages have been well simulated in this model , the behavior at early ages can not be well reproduced , which is also an artifact of the penna - type genetic models . from fig . [ fig - clonemort ] for genetically identical populations , it can be found that some populations have unrealistic zero mortality at some early ages . thus , the effects for the early ages studied in the experiments , such as the investigations of genetic variation for ln - mortality contributed by steady - state population or by new mutations @xcite , can not be produced in this model . more efforts should be made to avoid this difficulty , e.g. , by considering different kinds of genes before and after the reproduction age @xcite . we thank scott d. pletcher and naeem jan for very helpful discussions and comments . this work was supported by sfb 341 . here an example of the analytic solution for this stochastic model is presented , for the case where the reproduction is allowed in the aging process of genetically identical population , but no mutation occurs when generating the genomes of offsprings . thus , the individuals keep homogeneous , characterized by the same bit - string @xmath42 with @xmath43 the length of genome ( @xmath44 in above studies ) . when the system evolves to the steady state , the population size at timestep @xmath18 of this state @xmath45 as well as the verhulst factor @xmath46 can be considered as constant . thus , the numbers of individuals with ages from @xmath1 to @xmath43 at this step @xmath18 are @xmath47 where @xmath39 is the living probability of individual at age @xmath2 , as defined in eq . ( [ liveprob ] ) , and the individuals of age zero ( newly born ) are generated by the ones with reproducible age ( from age @xmath15 to @xmath16 ) , that is , @xmath48 \nonumber\\ & = & bv[n_{r_{\rm min}-1}(t-1)g(1,2, ... ,r_{\rm min } ) + n_{r_{\rm min}}(t-1)g(1,2, ... ,r_{\rm min}+1 ) \nonumber\\ & + & \cdots+n_{r_{\rm max}-1}(t-1)g(1,2, ... ,r_{\rm max } ) ] \label{a3}\end{aligned}\ ] ] with the birth rate @xmath14 . consequently , the number of individuals with certain age @xmath2 ( @xmath49 ) can be expressed as @xmath50 therefore , if @xmath51 is unchanged for the steady state , all the @xmath52 , @xmath53 , will also keep unchanged , i.e. , independent of timestep @xmath18 , and then the survival rate @xmath54 can be obtained from eq . ( [ a2 ] ) , that is , @xmath55 and @xmath56 the verhulst factor can be eliminated when calculating the normalized rate : @xmath57 and from the definition of eq . ( [ mortfunc ] ) one can obtain the normalized mortality function , which is the same as eq . ( [ hommort ] ) . the constant property of the population size @xmath20 and the number @xmath51 for age @xmath9 , as well as the above analytic result of the mortality function have been confirmed by the simulation . moreover , the steady state condition can be derived from eqs . ( [ a3 ] ) and ( [ a4 ] ) , which is @xmath58=1 , \label{a5}\end{aligned}\ ] ] depending on the parameters @xmath14 , @xmath15 , and @xmath16 . j. w. vaupel , j. r. carey , k. christensen , t. e. johnson , a. i. yashin , n. v. holm , i. a. iachine , v. kannisto , a. a. khazaeli , p. liedo , v. d. longo , y. zeng , k. g. manton , and j. w. curtsinger , _ science _ * 280 * , 855 ( 1998 ) .

a stochastic genetic model for biological aging is introduced bridging the gap between the bit - string penna model and the pletcher - neuhauser approach . the phenomenon of exponentially increasing mortality function at intermediate ages and its deceleration at advanced ages is reproduced for both the evolutionary steady - state population and the genetically homogeneous individuals . : biological aging ; mortality ; penna model .

The unidentified United States spy being swapped as part of a diplomatic breakthrough between the U.S. and Cuba is almost certainly a former cryptographer in Cuba’s Directorate of Intelligence who worked secretly for the CIA until he was arrested on espionage charges in the mid-1990s, according to a former U.S. intelligence officer and other sources. Rolando “Roly” Sarraff Trujillo was “an expert on cryptography for the Cuban Ministry of Interior who was arrested in 1995 and sentenced to 25 years in jail,” said Chris Simmons, a former Defense Intelligence Agency specialist on Cuba. “I know of all the Cubans on the list of people in jail and he is the only one who fits the description” of the unnamed asset in question, Simmons added. “I am 99.9 percent sure that Roly is the guy.” Keep up with this story and more by subscribing now The agent, U.S. officials said, was exchanged for the remaining three members of the so-called “Cuban Five,” a group of operatives arrested in Florida on espionage charges in 1998. Another element of the agreement, which ended the decades-long feud between the U.S. and Cuba, was Havana’s decision to free Alan Gross, a U.S. Agency for International Development contractor imprisoned on the island since 2009 on charges of trying to subvert the state. In a speech on Wednesday, Cuban President Raul Castro said that a spy of “Cuban origin” was being released. But neither Cuba nor the U.S. would identify the operative in question or comment on Sarraff Trujillo. DNI spokesman Brian P. Hale said in a prepared statement that the asset being released spent 20 years in a Cuban prison for his work for the U.S. Many of the details of his cooperation are classified, but Hale said he was “instrumental in the identification and disruption of several Cuban intelligence operatives in the United States and ultimately led to a series of successful federal espionage prosecutions.” Indeed, according to Hale, the spy “provided the information that led to the identification and conviction of Defense Intelligence Agency senior analyst Ana Belen Montes; former Department of State official Walter Kendall Myers and his spouse Gwendolyn Myers; and members of the Red Avispa network, or ‘Wasp Network,’ in Florida, which included members of the so-called Cuban Five.” On Wednesday, the Miami Herald’s Spanish-language edition also reported that its sources believe that Sarraff Trujillo was the spy. “Just as a matter of elimination,” it’s Sarraff Trujillo, Simmons said. A lieutenant colonel in the U.S. Army Reserve who also worked in counterterrorism operations in the Balkans and Iraq, Simmons runs a website called Cuba Confidential. On May 27, 2012, he wrote on his site that in 1994 Sarraff Trujillo was persuaded by a DGI colleague, José Cohen Valdés, to steal information that he could use to facilitate his defection to the U.S. Sarraff Trujillo, according to Simmons, gave him the info to pass along to Langley. “Cohen planned to bring Sarraf Trujillo and another individual with him in a mass defection,” Simmons wrote. Apparently, the plan didn’t work out. As Simmons explains on his blog: “Sarraff Trujillo started passing files [and] Cohen began indiscreetly spending the considerable cash the CIA paid for Sarraff Trujillo’s treasure trove of intelligence. In short order, the two men came under surveillance. Cohen reportedly noted the surveillance and had his brother-in-law signal the CIA station in Havana for an emergency extraction. Cuban counterintelligence videotaped his brother-in-law’s assistance, for which he was subsequently jailed. Cohen and the second individual successfully escaped, despite the extensive counterintelligence coverage. Sarraff Trujillo was arrested and sent to prison.” Simmons told Newsweek that the Cuban spy did such damage to Havana’s intelligence apparatus that “the only thing that saved him from execution was the fact that both his parents were retired senior intelligence officers.” Paul McKenna, the court-appointed lawyer for Gerardo Hernandez, one of the Cuban Five who is being released in the deal, said he had “no idea” who the U.S. spy was. “If I’d known they had a person like that,” McKenna told Newsweek in a telephone interview from his office in Coral Gables, Fla., “we would have pressed for an exchange a long time ago.” Before Gross was arrested, McKenna said he constantly asked Cuban officials on trips to the island whether they had someone who they could swap for Hernandez and they said no. “They would just shrug it off,” he said. When he pressed for a possibility of a trade of Gross for his client, he said, one Cuban official told him, “Leave the political to us.” Following the ages-old rules of espionage, it’s entirely possible that Sarraff Trujillo was under orders never to reveal his connection to U.S. intelligence. McKenna said when he visited his his client in jail, he “gave us only name, rank and serial number” for a number of years before his superiors in Cuba cleared him to admit he was a spy. The so-called “Cuban Five” were indicted on 25 different counts related to espionage. After a plane piloted by anti-Castro exiles was shot down as it flew into Cuban airspace, the government added an additional murder indictment to charges against Hernández. “I’m very happy for my client,” McKenna said. “He’s going home to his wife after 14 years.” As for Simmons, he said that any deal that got Sarraff Trujillo out of prison “was worth it.” ||||| There was no hint in December 2013, when President Barack Obama shook hands with his Cuban counterpart Raul Castro, that something bigger was afoot between the U.S. and its Cold War nemesis. Their encounter at a memorial service in Johannesburg for South African leader Nelson Mandela happened as Obama strode through the dignitaries’ area. While the event created media buzz, it was dismissed at the time by Obama’s deputy national security adviser, Ben Rhodes, as nothing more than a handshake. What the world didn’t know was that secret negotiations had already been under way for months, with Obama pursuing a deal to change the most fraught diplomatic relationship in the Western Hemisphere. And the man leading the talks? Rhodes, who’s one of Obama’s most trusted aides. “These 50 years have shown that isolation has not worked,” Obama said in Washington on Wednesday as he announced the rapprochement. “It’s time for a new approach.” Related: The move toward normalizing relations means not simply the opening of an American embassy in Havana but the easing of restrictions on limited travel and commerce that have blocked U.S. investment in the island nation and kept aficionados from legally bringing Cuban cigars to U.S. soil. The thaw was wrapped into the release of American aid worker Alan Gross and the exchange of a U.S. spy for three Cuban intelligence agents. Photographer: Chip Somodevilla/Getty Images U.S. President Barack Obama shakes hands with Cuban President Raul Castro during the official memorial service for former South African President Nelson Mandela at FNB Stadium in Johannesburg, on Dec. 10, 2013. Close U.S. President Barack Obama shakes hands with Cuban President Raul Castro during the... Read More Close Open Photographer: Chip Somodevilla/Getty Images U.S. President Barack Obama shakes hands with Cuban President Raul Castro during the official memorial service for former South African President Nelson Mandela at FNB Stadium in Johannesburg, on Dec. 10, 2013. Secret Meetings Obama in early 2013 authorized the senior-level talks toward restoring diplomatic relations that were severed 53 years ago, according to U.S. officials who spoke on condition of anonymity to discuss diplomatic matters. He designated two White House aides -- Rhodes and Ricardo Zuniga, the senior director for Western Hemisphere Affairs on the National Security Council staff -- to try to work out a deal. Initial contacts were conducted through diplomatic interest sections, maintained under Swiss auspices, and through U.S. and Cuban missions to the United Nations in New York. The effort was backed up with help from Canada and the Vatican, Obama administration officials told reporters on Wednesday. There were about seven secret meetings between U.S. and Cuban officials starting in June 2013 in Ottawa, the Canadian capital, according to an official familiar with the talks, who asked not to be named or identified by country. While Canadian officials didn’t participate in the negotiations, Ottawa was a diplomatically attractive meeting place. Pope Francis “We have unbroken diplomatic relations with Cuba, friendly relations with Cuba, and very intimate and close relations with the United States,” Brian Mulroney, who was prime minister of Canada from 1984 to 1993, said in a telephone interview. In recent months, Pope Francis appealed directly to Castro to release Gross and to Obama to free the imprisoned Cubans as a way to spur broader rapprochement. The first Latin American pontiff wrote the leaders urging them to “resolve humanitarian questions of common interest, including the situation of certain prisoners, in order to initiate a new phase in relations,” according to the Vatican’s Secretariat of State. The accord began to take final shape at an encounter between U.S. and Cuban envoys hosted by the Vatican where issues including the prisoner transfers were resolved, according to an Obama administration official. Cuba came up in the first meeting that then-U.S. Senator John Kerry and Obama had in early 2013 to discuss the prospect of Kerry replacing Hillary Clinton as secretary of State, a State Department official said. The two men agreed that existing policy was hurting U.S. interests, the official said. Kerry Role Four times this summer, Kerry had unannounced phone calls with Cuban Foreign Minister Bruno Rodriguez that focused solely on Gross’s release, according to a State Department official. In at least one, Kerry told his Cuban counterpart that if anything happened to the ailing Gross, who was detained in 2009, the island nation’s relationship with the U.S. would never improve. The five-year standoff over Gross is just one part of long-complicated relationship with Cuba, established decades before Fidel Castro’s rise to power. The U.S. controlled Cuba for four years following the Spanish-American War until its independence in 1902. Successive governments ruled the island until military leader and former Cuban President Fulgencio Batista seized power in 1952. His authoritarian regime fueled a rebellion led by Fidel Castro. Expectations for democratic change after Batista fled in 1959 were dashed as Castro executed or imprisoned thousands of opponents and seized land and sugar mills owned by Cubans and Americans. His embrace of the Soviet Union established Cuba as a U.S. adversary in the escalating Cold War. Cold War That led President Dwight Eisenhower to impose a partial embargo on exports and sever diplomatic ties, followed by bans on travel and commercial transactions set by his successor, President John F. Kennedy. The U.S. also waged covert attempts to destabilize the government -- including at least eight assassination plots against Castro. The agreement with Cuba toward normalizing relations is the latest twist in a pattern of shifts in U.S. embargo and travel policies, which have loosened and tightened over the decades. Even as he announced the change, Obama said Cuba still needs to make progress on human rights and economic reform. “Today Cuba is still governed by the Castros and the Communist Party that came to power half a century ago,” he said. “Neither the American nor Cuban people are well-served by a rigid policy that’s rooted in events that took place before most of us were born.” ‘Worst Negotiator’ Republican Senator Marco Rubio of Florida denounced the change, calling Obama “the worst negotiator” since President Jimmy Carter, who dropped the travel ban and let Cuban-Americans travel to the island. The ban was later revived under Ronald Reagan in the 1980s, while U.S. sanctions were tightened again in 1996 after two planes operated by a Cuban exile group were shot down, killing four people. Cuba’s current desire for rapprochement with the U.S. is rooted in economic reality. Its longtime patrons, Russia and Venezuela, are being squeezed by plummeting oil prices. Raul Castro, speaking to his nation on Wednesday at the same time Obama addressed the American public, said “the progress achieved in the exchanges we’ve had shows that it’s possible to find solutions to many problems.” “We have to learn the art of living together with our differences in a civilized way,” Castro said in Havana. Intelligence Agent Obama said that Cuba was on the agenda when he met with Pope Francis at the Vatican in March. The pope “played a very important role,” Obama said in an interview with ABC News, calling the pontiff “the real deal, a remarkable man.” The Vatican, in a statement, said, “The Holy Father wishes to express his warm congratulations for the historic decision” to normalize relations, “with the aim of overcoming, in the interest of the citizens of both countries, the difficulties which have marked their recent history.” Besides Gross, the accord also freed an unnamed U.S. agent who had been imprisoned in Cuba for almost 20 years. Without divulging details, Obama said the man had furnished vital information used to break up Cuban spying operations in the U.S. He is “one of the most important intelligence agents that the United States has ever had in Cuba,” the president said. Gross, a 65-year-old Maryland resident, was arrested in 2009 while working to expand Internet access for Havana’s Jewish community. Accused of undermining the Cuban state, he was sentenced to 15 years in prison. Corned Beef The death in June of his mother, Evelyn, was a difficult blow, according to Gross’s wife, Judith. He had appealed to Cuban authorities for a furlough on humanitarian grounds to grant his mother’s request to see him before she died of lung cancer. He went on a hunger strike in April to protest the Cuban and U.S. governments’ failure to resolve his situation. Cuban officials refused his request, leaving Judith Gross “extremely worried” about her husband’s psychological health. On Wednesday morning, with the deal completed, he left Cuba aboard a U.S. government plane, and Obama called him in mid-flight to congratulate him on his freedom. Gross was joined by his lawyer, Scott Gilbert; his wife; Senator Patrick Leahy of Vermont, and Representative Chris Van Hollen of Maryland, both Democrats. On board, they’d brought along treats the aid worker hadn’t enjoyed for five years: his favorite sandwich -- corned beef on rye with mustard -- plus potato latkes and applesauce to celebrate Hanukkah, and a bowl of popcorn. As soon as they got out of Cuban airspace, he called his two daughters. ‘Best Hanukkah’ Upon arriving at Andrews Air Force Base outside Washington, Gross was greeted by Kerry, who happened to have returned from a trip to Europe to the base minutes after Gross’s plane landed. After welcoming Gross home, Kerry sat with the former prisoner, his friends and family in a hangar at the air base where they watched Obama’s speech on Cuba together. In brief remarks to reporters in Washington Wednesday afternoon, Gross thanked Obama, U.S. lawmakers and Jewish organizations for pressing for his release. “It was crucial to my survival knowing that I was not forgotten,” he said. “It’s the best Hanukkah I’ll be celebrating in a long time.” To contact the reporter on this story: Terry Atlas in Washington at tatlas@bloomberg.net To contact the editors responsible for this story: John Walcott at jwalcott9@bloomberg.net Michael Shepard, Mark McQuillan ||||| White House press secretary Josh Earnest was asked on Wednesday if the U.S. thought economic pressures on Russia would produce positive results, since a similar approach in Cuba failed. (AP) White House press secretary Josh Earnest was asked on Wednesday if the U.S. thought economic pressures on Russia would produce positive results, since a similar approach in Cuba failed. (AP) The Cuban government on Wednesday freed a U.S. spy whom President Obama described as one of most important intelligence agents that the United States has ever had in the Communist country and who helped unravel several long-running Cuban espionage operations. U.S. officials said the release of the Cuban-born spy, identified as Rolando Sarraff Trujillo by a U.S. official, was a major priority for the intelligence community as part of any deal with the Cubans. That agreement, Obama said, also included the exchange of three Cuban spies by the United States and the release of former U.S. aid worker Alan Gross by Cuba on humanitarian grounds. The choreographed exchange ranked as one of the most significant spy swaps in recent memory and came four years after the United States exchanged 10 “sleeper” agents with Russia in return for the release of several Russian nationals who had spied for the West. Little is known about Trujillo other than that he had been imprisoned for nearly two decades and presumably had been working on behalf of either the FBI or the CIA long before that. Trujillo’s identity — first disclosed by Newsweek.com — was later confirmed by a senior American official, who spoke on condition of anonymity. In a highly unusual disclosure, the Obama administration on Wednesday revealed specific operations that the spy had helped the United States penetrate, saying he provided critical information that led to the arrests of those known as the “Cuban Five;” of former State Department official Walter Kendall Myers and his wife, Gwendolyn Steingraber Myers; and of the Defense Intelligence Agency’s top Cuba analyst, Ana Belen Montes. View Graphic Where U.S.-Cuba relations stand and what may change Although the U.S. intelligence community is believed to have significant operations in Cuba, the existence of a single asset who was instrumental to so many high-profile counterintelligence cases was previously unknown. While U.S. officials say the spy was ranked among the United States’s best assets in Cuba, a former senior CIA official said there was another alongside him, an individual known as “Touchdown,” who defected in the late 1980s. Touchdown revealed that many of the CIA’s assets in Cuba were double agents. The Myers investigation was one of the most serious espionage cases involving the State Department in recent years. The FBI long suspected there was a mole in the agency but did not have a name. In 2009, as part of its counterintelligence operations, the FBI launched a “false flag” operation against the Myerses involving an undercover FBI agent posing as a Cuban intelligence emissary. In a string of recorded meetings, the couple described their ties to the Havana government. They would later plead guilty to spying. In 2010, the husband was sentenced to life in prison; his wife received nearly seven years. The FBI did not disclose in its indictment how law enforcement officials initially learned about the couple’s activities. Montes, the DIA analyst, was also spotted early by the Cuban government in a “classic tale of recruitment,” according to the FBI. In 1984, Cuban officials learned she was “sympathetic to their cause,” and she soon agreed to help, landing a job at the agency in 1985. According to the FBI at the time, it was a DIA colleague who reported her in 1996 to a security official, suspecting she might be “under the influence of Cuban intelligence.” The bureau made no mention of its secret asset in Cuba, likely to protect him, even though he was already in prison. In less than two minutes, here are the key moments from President Obama's speech about changes to relations with Cuba on Wednesday. (Sarah Parnass/The Washington Post) Montes was arrested days after the Sept. 11, 2001, terrorist attacks and pleaded guilty in 2002. She was sentenced to 25 years in prison. Another woman, Marta Rita Velazquez, whom the FBI said introduced Montes to Cuban intelligence, was charged in 2013 with conspiracy to commit espionage. Velazquez, of Puerto Rico, lives in Sweden. It’s unclear what role what the spy identified as Trujillo played in the arrest of the Cuban Five — three of whom were released Wednesday and two of whom were released from prison earlier. But, as in the other cases, he appears to have provided information to U.S. intelligence before he was imprisoned in Cuba. According to the indictment of the Cuban Five, U.S. authorities learned as early as 1995 that Cuban intelligence had sent operatives to the United States. The U.S. intelligence community issued only a brief statement after the spy exchange on Wednesday. “Information provided by this person was instrumental in the identification and disruption of several Cuban intelligence operatives in the United States and ultimately led to a series of successful federal espionage prosecutions,” said Brian Hale, a spokesman for the Office of the Director of National Intelligence. Hale added it was a “fitting closure to this Cold World chapter of U.S.-Cuban relations.” ||||| President Barack Obama announces a shift in policy toward Cuba while delivering an address to the nation from the Cabinet Room of the White House in Washington, December 17, 2014. MIAMI Some Cuban exiles responded with outrage. Others with ecstasy. News on Wednesday that the United States will restore diplomatic relations with Cuba for the first time in more than a half century divided America's 1.5-million-strong Cuban exile community and threatened to shake up the political landscape in the vital battleground state of Florida. The reaction in Florida, which is home to about 80 percent of the nation's Cuban-American population, reflects a generational shift in an exile community whose powerful political influence in the United States and steadfast support for the Republican Party helped keep U.S. sanctions on Cuba in place for decades. But with President Barack Obama's vow to push for "an honest and serious debate" about lifting the United States' long-standing economic embargo against Cuba, many Cuban exiles welcomed the turn, seeing a chance for more engagement with the homeland they left behind. "It's amazing," said Hugo Cancio, who came to Miami in the 1980 Mariel boatlift and runs a magazine with offices in Miami and Havana. "This is a new beginning, a dream come true for the 11.2 million Cubans in Cuba, and I think it will provoke a change of mentality here too in this community." "I'm ecstatic," he added. "I've been working for this moment for 25 years". Such enthusiasm was not universal. In Miami's Little Havana neighborhood, occupants of passing cars screamed "Obama traitor" in Spanish. Other people on a sidewalk shouted "Obama communista." "This is nothing to be happy about," said Maria-Angeles Martinez, 50, who joined a crowd voicing displeasure at Versailles, a popular Cuban restaurant. "I don't believe in talking about anything with the Castros. It's freedom or nothing." Hardcore foes of former Cuban President Fidel Castro and his brother and current President Raul Castro have been a potent political force in Florida, one of the country's most hard- fought states in presidential elections. "DRAMATIC OVERREACH" Older exiles who oppose any opening to Cuba still wield considerable influence. Jeb Bush, the former Florida governor who on Tuesday said he was actively exploring a presidential bid in 2016, was quick to criticize the White House's move to restore diplomatic ties as "dramatic overreach." But the diehard anti-Castro generation is aging. And with many younger exiles having arrived since 1980 with no direct memories of life under Castro and many more Cuban-Americans born in the United States, there is a younger generation of Cuban-Americans that is more pragmatic and more influenced by the needs of relatives who remain in Cuba. Obama's announcement could complicate efforts by Bush, a Republican, to rally support for a presidential bid in a Cuban-American community whose divisions may be accentuated by a restoration in diplomatic ties. Many Republicans have struggled to win the presidency by taking Florida's Electoral College votes, which at 29 ties it with New York as No. 3 among the U.S. states in electoral votes. Obama won Florida twice. Bush, whose father, George H.W., and brother George W. were both U.S. presidents, is considered the Republican frontrunner in the 2016 race for the White House. Obama's announcement on Cuba was welcomed by younger Cuban-Americans who have increasingly pushed for change and vote Democrat in growing numbers, a contrast to older exiles who believe President John. F. Kennedy - a Democrat - betrayed them during the failed 1961 Bay of Pigs invasion. "It's no exaggeration to say that this is a historic day," said Pedro Freyre, a Cuban-American attorney in Miami who was formerly a Republican and a one-time hardliner on Cuba but now calls himself a conservative Democrat. "I think it is the right thing to do at the right time." Some Cuban exiles embraced the prospect of trying something new with Cuba after so many years. At Sergio's, a popular Cuban restaurant in Miami, Octavio De Armas, 62, speculated about the future of an island he left as a child, as he sipped a Cuban espresso sitting at a outdoor patio. "If things like this cafe can start happening there, if people can have a better life, I'm all for change," he said. (Additional reporting by Letitia Stein in Tampa, Fla.; Editing by Jason Szep and Leslie Adler)

– The historic thaw in US-Cuba relations didn't happen overnight, but came after more than a year of secret talks that had already been going on for months when President Obama caused a stir by shaking Raul Castro's hand at Nelson Mandela's funeral last year. Insiders tell Bloomberg that at least seven high-level meetings were held in Ottawa starting in June 2013. The Canadian capital was seen as an ideal meeting place because of the country's close ties to both Cuba and the US, although the Canadians didn't take part in the talks. Pope Francis—the first-ever pontiff from Latin America—also played a key role. He pushed both sides to talk to each other and reportedly hosted the final negotiation session at the Vatican. More: The US spy freed as part of the deal that saw American aid worker Alan Gross released has been identified by Newsweek as Rolando Sarraff Trujillo, a former cryptographer in Cuba’s Directorate of Intelligence who was sentenced to 25 years after being arrested for spying for the US in 1995. Trujillo is believed to have exposed several long-running Cuban espionage operations before he was caught, including the "Cuban Five," whose remaining three members were exchanged for him. The US hasn't named Trujillo as the released spy, but US officials say he was one of the most important assets the US ever had in Cuba and his release was a major priority, reports the Washington Post. "Information provided by this person was instrumental in the identification and disruption of several Cuban intelligence operatives in the United States and ultimately led to a series of successful federal espionage prosecutions," a spokesman for the Office of the Director of National Intelligence says. American lawmakers had mixed reactions to the shift, and Reuters found a similar split in Miami's Little Havana. "This is a new beginning, a dream come true for the 11.2 million Cubans in Cuba, and I think it will provoke a change of mentality here, too, in this community," says a magazine publisher who came to the US in the 1980 Mariel boatlift. Others on the streets, however, made their feelings of betrayal evident with shouts like "Obama communista!"

the differential diagnosis of dystonia includes : adverse drug reaction , local anesthetic reaction , emergence delirium , hysterical response , and shivering . summaries of case reports of dystonic reactions following propofol or ondansetron have been published . however , to our knowledge , there has been no case report of a patient demonstrating delayed dystonic movements after general anesthesia occurring only when falling asleep , with no additional symptoms and the patient being totally unaware of the movements . a 10-year - old , 35 kg , american society of anesthesiologists physical status i girl was scheduled for outpatient foot surgery . after premedication with midazolam 10 mg per oral , an uneventful induction of anesthesia was performed with sevoflurane , followed by placement of an intravenous ( iv ) line . propofol 30 mg and alfentanil 0.125 mg were given to facilitate the placement of a laryngeal mask airway ( lma ) . iv medications administered during the 60 minute procedure included : fentanyl 0.01 mg , morphine 4 mg , ketorolac 15 mg and dexamethasone 4 mg . at the completion of surgery , the patient was transported to the post anesthesia care unit ( pacu ) , where she recovered quickly . after about 45 minutes in the pacu , the patient was returned to the same day surgery unit where she received acetaminophen with codeine for pain control . approximately two hours after emergence from anesthesia , the patient complained of nausea and ondansetron 3 mg was administered iv . approximately 30 minutes later she started having jerking movements of her arms and torso every time she would drift off to sleep . initially the movements lasted for several seconds but during the course of the day these movements developed into shaking , seizure - like movements of her upper body and head lasting several minutes . diphenhydramine 25 mg iv was given as an attempt to treat a dystonic reaction but did not result in any improvement . the symptoms persisted at home ( video 1 - provided by the patient 's parents and oral and written consent to publish pictorial content of the procedure was obtained ) . over the next four days the symptoms the differential diagnoses of postoperative dystonic movements include adverse drug reaction , local anesthetic reaction , emergence delirium , hysterical response , and shivering . the diagnosis of hysterical response is unlikely although a psychogenic reaction could not absolutely be ruled out . most of the reported cases of abnormal movements induced by propofol , the phenomena occurred during induction , emergence or shortly thereafter , while the patients were awake and fully aware of the involuntary movements . in some of these cases there was the appearance that the patients were non - responsive when in all reality the patient was able to hear and see the world around them . there have also been reports describing delayed onset of propofol induced neuro - excitatory symptoms starting more than 60 minutes after emergence from anesthesia . islander and vinge reported 5 out of 44 cases and saravanakumar reported 6 out of 12 cases of postoperative dystonic movements with delayed onset of symptoms ( 85 min to 44 hours after emergence ) . our patient had received 30 mg of propofol during induction and the time from propofol injection to dystonic reaction was more than 3 hours . seizures are highly unlikely because the symptoms immediately subsided when awakening the patient and there were no postictal symptoms . the patient was never diagnosed with seizures , however , this diagnosis can not entirely be ruled out . the onset of symptoms after ondansetron has been reported to start in close proximity to the administration of the drug . in our case these movements include jerky movements of the head , neck , torso , and limbs , similar the movements in our patient . however , unlike in the previously described cases , our patient was not aware of the dystonic movements that only occurred after falling asleep . rhythmic movement disorder ( rmd ) is classified as a sleep - wake transition disorder according to the international classification of sleep disorders ( icsd ) . rmd is seen most frequently in infants and usually will disappear by four or five years of age , with a few cases presenting later in childhood and rarely in adulthood . using the flow chart shown in figure 1 , other movement disorders including dystonia , which occurs primarily during wakefulness , can be ruled out . modified after walters , a. flow chart for the differential diagnosis of sleep - related movement disorders.(complex : movements seem goal directed , purposeful . rmd : rhythmic movement disorder ) the movements most commonly seen with rmd include head banging , head rolling , body rocking and body rolling , exactly like the movements in our patients ( video 1 ) . the origin and cause of these movements is not yet known though it has been shown that this phenomenon is relatively benign . if they occur , they can be very disturbing and threatening for the patient , their families as well as their healthcare providers . because of the nature of the movements observed in our patient , we believe to present the first case of sleep - related rmd after general anesthesia .

dystonic movements after general anesthesia are very rare . the differential diagnosis includes adverse drug reaction , local anesthetic reaction , emergence delirium , hysterical response , and shivering . we present a case of a 10-year - old , otherwise healthy girl undergoing outpatient foot surgery . involuntary jerking movements of her arms and torso every time she would drift off to sleep started about 2.5 hours after emergence from general anesthesia . the patient was easily arousable and absolutely unaware of the movements . these movements lasted for several days before they resolved completely . we believe to present the first case of sleep - related rhythmic movement disorder after general anesthesia , considering the nature of the movements in our patient .

le succs de la fusion nuclaire par confinement magntique repose sur un confinement efficace des particules alpha , qui sont des ions hautement nergtiques produits par les ractions de fusion . de telles particules peuvent exciter des instabilits dans le domaine de frquence des modes dalfvn ( aes ) qui dgradent leur confinement et risquent dendommager lenceinte vide de racteurs futurs . afin de dvelopper des diagnostiques et moyens de contrle , une meilleure comprhension des comportements linaire et non - linaire des interactions rsonantes entre ondes plasma et particules nergtiques , qui constitue le but de cette thse , est requise . dans le cas dune rsonance unique et isole , la description de la dstabilisation des aes par des ions nergtiques est homothtique au problme de berk - breizman ( bb ) , qui est une extension du problme classique de linstabilit faisceau , incluant un amortissement externe vers un plasma thermique , et des collisions . un code semi - lagrangien , cobbles , est dvelopp pour rsoudre le problme aux valeurs initiales de bb selon deux approches , perturbative ( @xmath0 ) et auto - cohrente ( full-@xmath1 ) . deux modles de collisions sont considrs , savoir un modle de krook , et un modle qui inclue la friction dynamique et la diffusion dans lespace des vitesses . le comportement non - linaire de ces instabilits dans des conditions correspondantes aux expriences est catgoris en rgimes stable , priodique , chaotique , et de balayage en frquence ( sifflet ) , selon le taux damortissement externe et la frquence de collision . on montre que le rgime chaotique dborde dans une rgion linairement stable , et lon propose un mcanisme qui rsoud le paradoxe que constitue lexistence de telles instabilits sous - critiques . on dveloppe et valide des lois analytiques et semi - empiriques rgissant les caractristiques non - linaires de sifflet , telles que la vitesse de balayage , la dure de vie , et lasymtrie . des simulations de longue dure dmontrent lexistence dun rgime de sifflets quasi - priodiques . bien que ce rgime existe quel que soit lun des deux modles de collision , la friction et la diffusion sont essentielles pour reproduire lalternance entre sifflets et priodes de repos , telle quobserve exprimentalement . grce ces dcouvertes , on dveloppe une nouvelle mthode pour analyser des paramtres cintiques fondamentaux du plasma , tels que le taux de croissance linaire et le taux damortissement externe . cette mthode , qui consiste faire correspondre les simulations de cobbles avec des expriences daes qui prsentent des sifflets quasi - priodiques , ne requiert aucun diagnostique interne . cette approche est applique des aes induits par la toroidicit ( taes ) sur les machines jt-60 upgrade et mega - amp spherical tokamak . on obtient des estimations de paramtres cintiques locaux qui suggrent lexistence de taes relativement loin de la stabilit marginale . les rsultats sont valids en recouvrant la croissance et dcroissance de lamplitude des perturbations mesures , et en estimant les frquences de collision partir des donnes exprimentales dquilibre . bb : berk - breizman . + ep : energetic particles . + mhd : magneto - hydrodynamics . + saw : shear - alfvn wave . + ae : alfvn eigenmode . + tae : toroidicity - induced alfvn eigenmode . + bae : beta - induced alfvn eigenmode . + kaw : kinetic alfvn wave . + epm : energetic particle mode . + 1d @xmath2 6d : one dimension @xmath2 six dimensions . real space dimensions , unless explicitly specified to be phase - space dimensions . + nbi : neutral beam injection . + icrh : ion cyclotron resonant heating . + dce : displacement current equation . + bgk : bernstein - greene - kruskal . + cip : constrained interpolation profile . + r - cip : rational interpolation version of cip . + cip - csl : conservative semi - lagrangian version of cip . + iter : international thermonuclear experimental reactor ( cadarache , france ) . + jt-60u : jt-60 upgrade ( naka , japan ) . + diii - d : doublet iii - d ( san diego , usa ) . + mast : mega amp spherical tokamak ( culham , uk ) . + start : small tight aspect ratio tokamak ( formerly culham , uk ) . + nstx : national spherical torus experiment ( princeton , usa ) . + lhd : large helical device ( toki , japan ) . + chs : compact helical system ( toki , japan ) . + cobbles : conservative berk - breizman semi - lagrangian extended solver . + hagis : hamiltonian guiding center system . this manuscript has been written in an effort toward pedagogy , privileging clarity over details , physical pictures over mathematical developments . we hope it can be used as an introduction to the berk - breizman problem and its numerical computation . however we can not pretend being able to introduce notions such as nuclear fusion , magnetic plasma confinement , magneto - hydrodynamics ( mhd ) , kinetic theory , tokamak geometry , or particle orbits , with as much clarity as in well - known textbooks . for this reason , the reader is assumed to be familiar with the basis of the above fields . in this introduction we expose the background and motivation for our work . in an ignited tokamak operating with a deuterium - tritium mix , the confinement of @xmath3-particles is critical to prevent damages on the first - wall and to achieve break - even . the reason is that these high energy particles must be kept long enough in the plasma core to allow enough of their energy to heat thermal populations by slowing - down processes . a major concern is that high energy ions can excite plasma instabilities in the frequency range of alfvn eigenmodes ( aes ) , which significantly enhance their transport . ever since the recognition of this issue in the 1970 s , considerable progress has been made in the theoretical understanding of the principal alfvnic instabilities . however , the estimation of the mode growth rate is complex , and the question of their stability in iter @xcite remains to be clarified . in addition , estimation of the effect on transport and development of diagnostics and control schemes require significant progress on our understanding of nonlinear behaviors . we limit our framework to the tokamak configuration . in this work , we focus our interest on the toroidicity induced alfvn eigenmode ( tae ) @xcite , which is a shear - alfvn wave ( saw ) located in a gap of the saw continuum that is created by toroidal coupling of two successive poloidal modes , and which can be destabilized by resonant interactions with high - energy ions . taes have been observed to be driven by @xmath3-particles in burning plamas @xcite , ion - cyclotron - resonance heating ( icrh ) @xcite , and neutral beam injection ( nbi ) @xcite . in this work we consider only the latter situation ( nbi - driven taes ) . in general , taes are described in a three - dimensional ( 3d ) configuration space . however , near a phase - space surface where the resonance condition is satisfied ( resonant phase - space surface ) , it is possible to obtain a new set of variables in which the perturbation is described by a one - dimensional ( 1d ) effective hamiltonian in 2 conjugated variables @xcite , if we assume an isolated single mode . in this sense , the problem of kinetic interactions between taes and fast - particles is homothetic to a simple 1d single mode bump - on - tail instability . the so - called berk - breizman ( bb ) problem @xcite is a generalization of the bump - on - tail problem , where we take into account an external wave damping accounting for background dissipative mechanisms , and a collision operator . observed qualitative and quantitative similarities between bb nonlinear theory and both global tae simulations @xcite and experiments @xcite are an indication of the validity of this reduction of dimensionality . similar arguments exist for other alfvn wave instabilities such as the geodesic acoustic mode ( gam ) @xcite , and the beta alfvn eigenmode ( bae ) @xcite . these analogies enable more understanding of fully nonlinear problems in complex geometries by using a model that is analytically and numerically tractable . this approach is complementary to heavier 3d analysis . a feature of the nonlinear evolution of aes , the frequency sweeping ( chirping ) of the resonant frequency by 10 - 30@xmath4 on a timescale much faster than the equilibrium evolution , has been observed in the plasma core region of tokamaks jt-60 upgrade ( jt-60u ) @xcite , diii - d @xcite , the small tight aspect ratio tokamak ( start ) @xcite , the mega amp spherical tokamak ( mast ) @xcite , the national spherical torus experiment ( nstx ) @xcite , and in stellerators such as the large helical device ( lhd ) @xcite , and the compact helical stellerator ( chs ) @xcite . in general , two branches coexist , with their frequency sweeping downwardly ( down - chirping ) for one , upwardly ( up - chirping ) for the other . in many experiments , asymmetric chirping has been observed , with the amplitude of down - chirping branches significantly dominating up - chirping ones . chirping taes have been reproduced in 3d simulations with a hybrid mhd / drift - kinetic code @xcite , and with a drift - kinetic perturbative code @xcite . qualitatively similar chirping modes are spontaneously generated by the bb model , and have been shown to correspond to the evolution of holes and clumps in the velocity distribution . theory relates the time evolution of the frequency shift with the linear drive @xmath5 and the external damping rate @xmath6 @xcite , when the evolution of holes and clumps is adiabatic . the idea of using chirping velocity ( or sweeping rate ) as a diagnostic for growth rates looks promising . if we assume that the mode is close to marginal stability , @xmath7 , and if we further assume that holes and clumps are in the adiabatic regime , then the growth rates are simply obtained by fitting analytic prediction to experimental measurement of chirping velocity . however , these two assumptions are not verified in general , which limits the applicability of this simple approach . in most experiments , chirping events are quasi - periodic , with a period in the order of the millisecond . on the one hand , the long - time simulation of repetitive chirping with 3d codes is a heavy task , which has not been undertaken yet . on the other hand , simulations of the bb model with many chirping events have been performed @xcite , but such solutions do not feature any quasi - periodicity . in this sense , repetitive chirping that qualitatively agrees with an experiment has not been reproduced , neither with 1d nor 3d simulations . our main goals are to improve our understanding of wave - particle nonlinear resonant interactions , develop diagnostics and identify control parameters for aes . from these backgrounds , a straight - forward plan is to : * clarify the link between bb model and aes , * extend bb theory where it is insufficient to explain experimental observations , * analyze experimental data by applying the bb model to aes . in brief , we reduce the problem of taes to a numerically and analytically tractable paradigm , the bb problem . we make a survey of linear and nonlinear physics of the bb model , and work on improving our understanding , by extending theory and by using systematic numerical observations , focusing on the frequency sweeping regime . armed with new findings and robust numerical tools , we finally go back to the original problem of taes , explaining quantitative features of experimental observations , and developing a new method for accurate linear predictions . in chap . [ ch : tae ] , we review the physics of the tae , and simplify the description of the problem from 6d to 2d in phase - space , around a single resonant phase - space surface . the first step in this procedure is to isolate the gyromotion , which is decoupled from the wave for typical taes with @xmath8 khz , by changing variables to the guiding - center coordinates . this change of variables is based on the so - called lie transform perturbation theory , which we review in order to get a better grasp of involved hypothesis . then we show how to reduce the guiding - center hamiltonian , as well as collision operator and background mechanisms , and discuss limitations of this simplified description . in chap . [ ch : bbmodel ] , we review basic nonlinear physics of the bb problem . we develop and verify numerical tools that we use in following chapters . in particular , we develop and verify a kinetic code to solve the initial - value problem . we show that numerical simulations in experimentally relevant conditions , with cold - bulk and weak , warm - beam distributions , require a careful choice of advection scheme . among the family of so - called constrained interpolation profile ( cip ) schemes , a locally conservative version ( cip - csl ) displays the best convergence properties . as an intermediate summary , we cast the analogies between bb model and 1d description of taes . in chap . [ ch : nonlinearities ] , we investigate kinetic features of self - consistent interactions between an energetic particle beam and a weakly unstable electrostatic wave in 1d plasma , within the bb framework , with an emphasis on chirping regime and subcritical instabilities . we show that the nonlinear time - evolution of chirping in 1d simulations can be used to retrieve information about linear input parameters with good precision . we identify a regime where chirping events are quasi - periodical . this regime exists whether the collision model is annihilation / creation type , or takes into account dynamical friction and velocity - space diffusion . based on these findings , in chap . [ ch : experiment ] , we propose a new method to estimate local linear drive , external damping , and collision frequencies from the spectrogram of magnetic field variations measured by a mirnov coil at the edge of the plasma . this method , which relies on a fitting of normalized chirping characteristics between the experiment and bb simulations , is described and applied to tae experiments in mast and jt-60u . we show that the bb model can successfully reproduce features observed in the experiment only if the collision operator includes drag and diffusion terms . we find a quantitative agreement for the diffusion frequency , and a qualitative agreement for the drag frequency , between the values obtained with our fitting procedure , and an independent estimation obtained from experimental equilibrium measurements . in the conclusion ( chap . [ ch : conclusion ] ) , we summarize our findings , and we suggest numerical and experimental investigations these findings enable . the tae is a shear - alfvn wave located in a gap of the saw continuum that is created by toroidal coupling of two successive poloidal modes , which can be destabilized by energetic particles . this chapter deals with the modelization at several levels of complexity of an isolated single - mode tae . in sec . [ sec : review_tae ] , we give a short review of the basic tae physics , and of the state - of - the - art of its linear stability analysis , emphasizing a need for improved accuracy . when the tae is an isolated single - mode , it is possible to reduce the problem to a simple harmonic oscillator , by expanding the perturbed hamiltonian around a resonant phase - space surface . this reduction from 3d to 1d becomes particularly transparent in angle - action variables ( @xmath9 , @xmath10 ) , once the perturbation has been put in the form @xmath11 , where @xmath12 are integers . in sec . [ sec : gyrokinetic_tae ] , we show how to obtain the latter form . the first step is to separate the gyromotion , which does not resonate with typical taes , by changing variables to guiding - center coordinates . this procedure can be done while conserving the hamiltonian properties by making use of lie transform perturbation theory , which we review thoroughly . in sec . [ sec:3d_to_1d ] , we show how to reduce the hamiltonian , collision operator , and background damping mechanisms from their 3d description to a 1d model . this short review is intended to introduce notions and notations that we use when applying the bb model to the tae , and to motivate our linear analysis of taes . for a more comprehensive review of energetic - particle driven aes , see ref . @xcite . hereafter , we make use of magnetic flux coordinates @xcite , also called as straight field - line coordinates , ( @xmath13 , @xmath14 , @xmath15 ) , where @xmath13 , @xmath14 and @xmath15 are minor radius , poloidal and toroidal angle , respectively , to describe the nested poloidal flux surfaces of the equilibrium magnetic field @xmath16 . in these coordinates , @xmath16 takes the following form , @xmath17 where @xmath18 is the poloidal flux ( divided by @xmath19 ) , and the safety factor , defined by @xmath20 is the flux surface - averaged number of toroidal rotation that a field line undergoes in one poloidal rotation . , with and without coupling between @xmath21 and @xmath22 poloidal modes . the q profile has been modeled by @xmath23 , and the electronic density by @xmath24 [ @xmath25 m@xmath26 . other parameters are @xmath27 t , @xmath28 m , and @xmath29 m. note that the discrepancy , relatively far from resonance , between the upper branch of coupled continuum and the uncoupled @xmath21 branch , is accounted by errors of second - order in the aspect ratio . similar discrepancy is observed in fig . 1 of ref . @xcite for example . ] in an homogeneous magnetized plasma , linear ideal - mhd arguments show the existence of a shear - alfvn wave of frequency @xmath30 with the dispersion relation @xmath31 where @xmath32 is the alfvn velocity , and @xmath33 is the wave number in the direction of the equilibrium magnetic field @xmath16 . let us consider axisymmetric toroidal plasmas . in the cylindrical limit , the periodicities of the system require that there exists two integers , a toroidal mode number @xmath34 and a poloidal mode number @xmath35 , such that @xmath36 where @xmath37 is the distance from the symmetry axis of the tokamak to the magnetic axis . in a non - homogeneous plasma in a sheared magnetic field , both @xmath33 and @xmath38 are functions of @xmath13 . the simple dispersion relation eq . ( [ eq : saw_disp_rela ] ) is still valid in this configuration @xcite , and it is called the alfvn continuum . since phase velocity is a function of radius , a wave packet with finite radial extent would suffer from phase - mixing , the so - called continuum damping . except for energetic particle modes , which are outside of the scope of this work , resonant drive by fast particles is not enough to overcome this damping . however , a toroidal coupling of two successive poloidal modes @xmath35 and @xmath39 breaks up the continuous spectrum . this is illustrated in fig . [ fig : continuum ] , which shows the alfvn continuum for @xmath40 , @xmath21 and @xmath41 , in cylindrical geometry , where two poloidal continuum are decoupled , and in toroidal geometry , with a two - mode coupling model @xcite . the latter is obtained with equilibrium plasma parameters corresponding to jt-60u shot e32359 at @xmath42s , which we analyze in chap . [ ch : experiment ] , assuming concentric circular magnetic flux surfaces , retaining toroidicity effects in the first order in inverse aspect ratio . though we show only the @xmath43 half - plane , the continuum is symmetric with respect to @xmath44 . coupled modes are ( @xmath34 , @xmath35 ) and ( @xmath45 , @xmath46 ) for @xmath47 , and ( @xmath34 , @xmath39 ) and ( @xmath45 , @xmath48 ) for @xmath49 . the gap is centered at a radius @xmath50 such that @xmath51 , where the two continuous spectra would cross in the absence of coupling , and where @xmath52 . the resulting discrete eigenmode is a tae , at a frequency @xmath53 . for a deuterium plasma with typical magnetic field @xmath54 and density @xmath55 , the alfvnic energy is @xmath56 , which is in the range of passing particles induced by nbi . for iter parameters , @xmath57 , which is in the range of passing @xmath3-particles born from fusion reactions . in both cases , taes can be driven unstable by resonance with energetic particles . for far - passing particles , the resonance condition is @xmath58 , where @xmath59 where @xmath60 and @xmath61 are frequencies of toroidal motion and poloidal motion , respectively , and @xmath62 for co - passing particles , @xmath63 for counter - passing particles @xcite . since we analyze taes driven by co - injected ions , we can simplify following discussions by considering only co - passing particles . then , the resonance condition is @xmath64 in theory , the linear growth rate @xmath65 is positive when the drive by fast particles overcomes damping processes to background plasma . the growth rate can be estimated either by linear stability codes , such as penn @xcite , task / wm @xcite , nova - k @xcite , or castor - k @xcite ; or by gyro- or drift- kinetic perturbative nonlinear initial value codes , such as fac @xcite or hagis @xcite . the analysis requires internal diagnostics that are not always available . the linear drive @xmath5 depends on several factors such as spatial and energy gradients of ep distribution , and alignment between particle orbit and the eigenmode . in the limit of large aspect ratio , analytic theory @xcite yields successful estimations of @xmath5 for well - defined numerical models @xcite however , in the general case , complicated factors cited above forbid accurate analytic estimation , as yet . moreover , improvements in measurement of ep distributions are needed to allow estimation of @xmath5 for experimental taes . the external damping rate @xmath66 involves complicated mechanisms , which include continuum damping ( since parts of the mode extend spatially into the continuum ) @xcite , radiative damping @xcite , landau damping with thermal species @xcite , and collisional damping by trapped electrons @xcite . most of these mechanisms are still under investigation , and can not be quantified by existing theory . experimentally , @xmath6 can be estimated by active measurements of externally injected perturbations @xcite . however , the applicability of this technique is limited to dedicated experiments . moreover , if the system is close to marginal stability , @xmath67 is sensitive to small variations of driving and damping terms , and is very sensitive to plasma parameters such as the @xmath68 profile . in addition , the existence of unstable aes in a regime where linear theory predicts @xmath69 , or subcritical aes , has not been ruled out . to access the subcritical regime , nonlinear analysis is necessary . therefore , accurate linear stability analysis requires significant theoretical and experimental improvements , or a new approach . since the kinetic equation is at the center of interest of this thesis , it is useful to get a deep understanding of its meaning , by reviewing its derivation from fundamental principles . the steps we summarize here are detailed in ref . @xcite for example . + a many - body system is completely described by the microscopic distribution @xmath70 , where @xmath71 , @xmath72 and @xmath73 are the position and velocity of a particle indexed as @xmath74 , and the sum is taken over all particles . to simplify the present discussion , we consider a single - species system of @xmath75 particles , without external forces , and normalize the total phase - space volume , assumed constant , to @xmath76 . substituting newton equations of motion into the partial time derivative of @xmath77 yields the so - called klimontovich - dupree equation , @xmath78 where @xmath79 is the acceleration due to microscopic electromagnetic fields , at the exception of those due to a particle located at @xmath80 , if such a particle exists . the microscopic electromagnetic fields obey maxwell equations , where density and current are velocity moments of @xmath77 . since it is impossible to reproduce any many - body experiment at the microscopic level , it is much more efficient to take an ensemble point - of - view , where distributions and fields are smooth functions of phase - space . the statistical properties are completely determined by the distribution @xmath81 , where @xmath82 is the probability of finding , at a time @xmath83 , particle 1 within @xmath84 , particle 2 within @xmath85 , @xmath2 and particle @xmath75 within @xmath86 , and @xmath87 is an infinitesimal phase - space volume at the neighborhood of @xmath88 . by integrating @xmath89 over all @xmath90 but @xmath91 , we can define the one - particle distribution function @xmath92 , where @xmath93 is the probability of finding one particle within @xmath84 at @xmath83 . @xmath92 is related to the microscopic distribution by @xmath94 where @xmath95 is the ensemble average @xmath96 . similarly , by integrating @xmath89 over all @xmath90 but @xmath91 and @xmath97 , we can define the two - body distribution function @xmath98 , which is related to the microscopic distribution by @xmath99 where we used a large particle number approximation , @xmath100 . in the absence of atomic and nuclear processes , @xmath75 is a constant , then the ensemble average of eq . ( [ eq : klimontovich_dupree ] ) yields @xmath101 where the average acceleration @xmath102 is given by electromagnetic fields that obey maxwell equations , where density and current are velocity moments of @xmath92 . the collision term , @xmath103 is shown to vanish in the absence of particle interactions , yielding vlasov equation , which is valid on a time - scale much shorter than a collisional time - scale . ( [ eq : averaged_klimontovich_dupree ] ) is not a closed equation , because the second part of the collision term involves expressions of the form @xmath104 . under the coulomb approximation , which forbids any retardation effect , and which is valid if the thermal velocity is much slower than the speed of light , we can reduce the latter term as a function of @xmath105 . similarly , the equation which gives the evolution of @xmath105 involves terms of the form @xmath106 , and so on . altogether , we have a chain of equations for which we need a closure . a collision operator is an approximative statistical operator that accounts for particle interactions , which provides such closure . a clear review of collision operators is given in ref . @xcite . in this thesis , we focus on a fokker - planck collision operator , which is based on the fact that , in a tokamak plasma , collisions are dominated by binary coulomb collisions with small - angle deflection . in the following , we write @xmath92 simply as @xmath1 . the kinetic equation , eq . ( [ eq : averaged_klimontovich_dupree ] ) , can be put in hamiltonian form , @xmath107 where @xmath108 is the hamiltonian , and @xmath109 are poisson brackets . the l.h.s . is the variation of @xmath1 following particle orbits , or so - called lagrangian derivative of @xmath1 , noted @xmath110 . , @xmath111 ) , delimited by a solid curve at @xmath112 and by a dashed curve at @xmath113 . the phase - space volume is constant , @xmath114 , and , in the absence of collision , the number of particles inside the volume is constant too . ] the fact that , in the absence of collisions , @xmath1 is conserved along particle orbits , can be seen as a direct consequence of liouville s theorem , which states that the density in phase - space is constant along particle orbits . let us consider an infinitesimal volume of phase - space @xmath84 surrounding a particle at @xmath115 at @xmath112 , as illustrated in fig . [ fig : liouville ] . the particle and all points of @xmath84 evolve following the equations of motion until a time @xmath113 where the particle is at @xmath116 , and @xmath84 is changed to a volume @xmath85 . liouville s theorem arises from the following properties , * since the points of the boundary of @xmath117 follow the equations of motion , in the absence of collisions , the number of particles inside @xmath117 is constant ; * time - evolution can be seen as a series of infinitesimal canonical transformations generated by the hamiltonian ; * poincar s invariant : the volume element in phase - space is a canonical invariant . + when working in canonical variables , it is easy to exploit the properties of a hamiltonian system . however , for some systems it is difficult to find canonical variables , and the most convenient variables may not be canonical . moreover , if some variables are canonical for the unperturbed system , they may be non - canonical for the perturbed one . by applying the lie near - identity transformation theory to the phase - space lagrangian , one can change any lagrangian into a simpler form in coordinates that reveal the symmetries of the system , and use this formulation to study the properties of a perturbed hamiltonian system in any arbitrary noncanonical variables @xcite . [ [ subsubsecnoncanhammechnoncanonical - hamiltonian - mechanics ] ] [ subsubsec : noncanhammech]noncanonical hamiltonian mechanics + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + consider a hamiltonian system with @xmath77 degrees of freedom . hamilton equations are given by the application of a variational principle to the scalar lagrangian @xmath118 , in some arbitrary coordinates @xmath119 on the @xmath120-dimensional extended phase space , ( @xmath83 , @xmath119 ) , @xmath121 where @xmath122 is an arbitrary parameter . hereafter , greek indices @xmath3 , @xmath123 and @xmath124 run from @xmath125 to @xmath126 , whereas latin indices @xmath127 and @xmath128 run from @xmath76 to @xmath77 , and @xmath74 , @xmath129 , @xmath130 from @xmath76 to @xmath126 . thus , any hamiltonian system is characterized by its lagrangian @xmath131 or equivalently by its fundamental one - form , @xmath132 . in the canonical extended phase - space @xmath133 , when @xmath134 is the time coordinate , @xmath135 where @xmath108 is the hamiltonian . however , in noncanonical variables , all the @xmath136 may be nonzero . from eq . ( [ eq : varprcple ] ) , which has the same form in any new coordinate system @xmath137 with @xmath138 , euler - lagrange equations are obtained as @xmath139 where @xmath44 is a tensor defined by @xmath140 and its restriction to the symplectic coordinates @xmath141 is the lagrange tensor . thus the flow @xmath142 is an eigenvector of @xmath143 with eigenvalue @xmath125 . the solution is unique only after a normalization . in physical terms , we can take @xmath144 . since the jacobian of the coordinate transformation @xmath145 is nonsingular , we can invert the lagrange tensor . the poisson tensor @xmath146 then yields the equations of motion , @xmath147 [ [ subsubsecpertthlie - transform - technique ] ] [ subsubsec : pertth]lie transform technique + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + we consider a fundamental one - form @xmath148 which consists of an equilibrium part @xmath149 for which the flow is well - known , and a small perturbation @xmath150 . we want to study the effect of the perturbation on the flow . the strategy is to search for a near - identity transformation that will reveal the symmetries of the perturbed system . indeed , if the fundamental one - form is independent of some coordinate @xmath151 , then , as an application of noether s theorem , @xmath152 revealing an exact invariant . the general form of a near - identity transformation with a small parameter @xmath153 is @xmath154 rather than an expansion in @xmath153 which is difficult to invert , we express the transformation in operator form . we denote a forward transformation @xmath155 , and a backward transformation @xmath156 . in the lie transform technique , the coordinate transformation is specified by a generator @xmath157 such that @xmath158 and @xmath159 . the forward transformation of a scalar @xmath160 into @xmath161 is given by @xmath162 where @xmath163 is defined by its action on a scalar @xmath164 , and its action on a one - form @xmath165 . the transformation of coordinates is just a special case of scalar transformation , @xmath166 where @xmath167 is the coordinate function . the transformation of a one - form @xmath168 into @xmath169 is given by the functional relationships , @xmath170 where @xmath171 and @xmath172 are scalar functions . [ [ higher - order - perturbation - theory ] ] higher order perturbation theory + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + we now consider a fundamental one - form in the form of an expansion @xmath173 . we introduce a push - forward transformation operator @xmath174 , where each @xmath175 is a lie transform operator , and @xmath176 is a short for @xmath177 . substituting these new definitions into eq . ( [ eq : pushforwoneform ] ) , we have @xmath178 , which yields for each successive order , @xmath179 , and @xmath180 let us recall that our aim is to simplify the fundamental one - form in the new coordinates @xmath181 . to this aim we have to solve successively the latter equations for the gauge scalar @xmath182 and the generating vector @xmath183 ( each @xmath184 is given by @xmath185 and the result of the preceding order @xmath186 ) . in these equations , the generating vector appears only in the one - form @xmath187 . we already discussed that @xmath188 has a unique null eigenvector . then we can add any multiple of this eigenvector to @xmath183 without changing the equations we are now trying to solve . let us suppose this eigenvector has a nonzero component in the time direction , then we can set @xmath189 so that the time - coordinate does nt change ( @xmath190 ) . at this point , we are left with @xmath120 unknowns , namely @xmath126 generating functions @xmath191 and one scalar gauge @xmath182 . a priori we should be able to bring the @xmath120 components of @xmath192 into a simpler form . a good strategy is to make all its symplectic components @xmath193 vanish by choosing @xmath194 let us now focus on the time component of the new one - form , @xmath195 it is convenient to introduce the lowest order velocity vector , defined as the time derivative along the unperturbed orbits of the coordinates : @xmath196 substituting the unperturbed equations of motion ( [ eq : unpeqmotion ] ) , we find that the scalar gauge is given by its total time derivative over the unperturbed orbit , @xmath197 in integrating the latter equation , we want to avoid any secularity effect . then we should remove any secular perturbation by taking @xmath198 where the average is to be taken over the unperturbed orbits . + finally , in the new coordinates @xmath199 z$ ] , the new one - form is given by @xmath200 if we choose the generating functions @xmath201 where the gauge scalar is given by @xmath202 and a tilde represents the oscillatory part . to illustrate the benefits of lie transform theory compared to classical perturbation theory , and to quantify its validity limit , we apply it to a simple mathematical problem in app . [ app : lie ] . guiding - center theory provides reduced equations of motion of a charged particle in a slowly - varying ( in time and space ) electromagnetic field , where the fast gyromotion is decoupled from the relatively slow drifting motion of the guiding - center . guiding - center theory is based on the closeness to the limit of a fixed and uniform magnetic field , where the orbit of a particle in a frame following its gyration center is a circle . the perturbation from this situation is quantified by a small parameter @xmath153 , if we assume the following ordering , @xmath203 where @xmath204 is the cyclotronic frequency ( or gyrofrequency ) , @xmath205 is the larmor radius ( or gyroradius ) , @xmath44 is a characteristic frequency of interest , and @xmath118 is the scalelength of field variation . on the one hand , the standard derivation of guiding - center equations of motion is based on an averaging procedure @xcite , which removes important properties of the hamiltonian formulation . on the other hand , the modern derivation @xcite is based on lie - transform perturbation theory . this approach preserves the validity of noether s theorem and the validity of liouville s theorem , to each order in @xmath153 . in addition , expansion to arbitrary order is straightforward . moreover , since we keep the hamiltonian formulation , further reductions of dimensionality are still possible with lie transforms . the starting point is the one - form in canonical cartesian phase - space ( @xmath206 , @xmath207 ) , @xmath208 where @xmath209 , and @xmath210 is the vector potential . the one - form can be expressed in noncanonical phase - space @xmath211 , and written as an expansion in @xmath153 , @xmath212 where @xmath213 and where @xmath214 is the scalar potential . in ref . @xcite , lie - transform theory is applied to change variables to new coordinates , where the new one - form @xmath181 does not depend on the gyroangle . when this procedure is carried up to the second order , we obtain the guiding - center one - form , @xmath215 where @xmath216 and the guiding - center coordinates @xmath217 as @xmath218 where @xmath219 is an orthogonal unit vectors system , @xmath220 , and @xmath221 . in eq . ( [ gc_oneform ] ) , the angle - action variables of the gyromotion , ( @xmath222 , @xmath223 ) , appear in canonical form in the symplectic part , and @xmath224 does not depend on @xmath222 . thus , since the gyromotion is irrelevant to fast - ion / tae interactions , we can drop the term @xmath225 in the guiding - center one - form . in ref . @xcite , the zeroth order guiding - center one - form @xmath226 is put in the form , @xmath227 where @xmath228 is the toroidal canonical angular momentum , @xmath229 and @xmath230 is the poloidal canonical angular momentum . the latter expression can be used as a starting point to develop an action - angle formalism where the perturbed hamiltonian takes a standard form . in ref . @xcite , a canonical transformation is performed to obtain @xmath231 where @xmath232 , @xmath233 , and @xmath234 are the unperturbed frequencies of the gyromotion , poloidal motion , and toroidal motion , respectively . @xmath235 and @xmath236 reduce to the geometric angles @xmath14 and @xmath15 if we neglect finite aspect ratio effects ( but we do not neglect them , since we would remove the toroidicity from which the tae originates ) . although taes resonate mainly with passing particles , when the source of high - energy ions is isotropic , a large fraction of the energy transfer may be accounted by resonance with the bounce - motion ( or banana motion ) of toroidally trapped particles @xcite . however , for tangential nbi ions , to which we confine our analysis , it is sufficient to describe resonance with far passing particles . in a gauge where the perturbed scalar potential is zero , the tae can be described by a perturbation hamiltonian , @xmath237 where @xmath238 is the guiding - center velocity . here , @xmath239 is the perpendicular part of the perturbed vector potential , and we have neglected a second order term @xmath240 . in a small plasma pressure ( small @xmath241 ) limit , we can neglect parallel gradients , then @xmath239 can be split into magnetic compression , @xmath242 and magnetic shear , @xmath243 where @xmath244 . for the tae , which is a shear alfvn wave , the latter part only is relevant , hence the excitation is described by a single scalar function @xmath245 . in ref . @xcite the perturbed hamiltonian is put in the form @xmath246 in arbitrary tokamak geometry , where ( @xmath247 , @xmath248 ) are angle - action variables for the solvable unperturbed hamiltonian @xmath249 , and @xmath250 is a triplet of three integers . substituting eq . ( [ eq : shear_part ] ) into eq . ( [ eq : perturbed_lag ] ) yields @xmath251 where @xmath252 is the lagrangian derivative of @xmath245 along unperturbed particle orbit , which can be removed from the lagrangian without altering euler equations . for a single @xmath253 mode of frequency @xmath44 , the eigenfunction takes the following form , @xmath254 where @xmath255 and @xmath214 are the amplitude and phase of the wave . substituting the eigenfunction and the expression @xmath256 into eq . ( [ eq : perturbed_lag2 ] ) , the tae excitation is reduced to @xmath257 \;+\ ; \mathrm{c.c.},\ ] ] where we have neglected time - derivation of slowly varying phase and amplitude of the wave . then we change the variables to the canonical angle - actions ( @xmath235 , @xmath236 , @xmath258 , @xmath259 ) , in order to express the perturbed hamiltonian as a fourier series in @xmath235 , @xmath260 where @xmath261 . \label{eq : vp_berk}\ ] ] formally , the problem is expressed in the desired form of eq . ( [ eq : perturbation_in_aa ] ) , but the numerical computation of the fourier components @xmath262 , which is needed for quantitative comparison of absolute physical quantities between 3d and 1d model , requires to relate geometric angles and canonical angles , which may be complicated depending on the equilibrium configuration . however , since each particle of the resonant phase - space surface interact with the wave in the same way at the same frequency ( though with different strength ) , comparison of quantities that are normalized to the mode frequency is possible , even without evaluating @xmath262 coefficients . if we consider only small toroidal mode numbers @xmath34 , @xmath34 and @xmath263 modes are isolated . let us consider a single toroidal mode number . on the one hand , since on a flux surface @xmath264 where a poloidal mode number @xmath35 is centered , the safety factor is @xmath265 , then we can estimate the distance @xmath266 between two neighbouring @xmath35 modes by writing @xmath267 , as @xmath268 on the other hand , the characteristic width of tae modes @xmath269 is of the order of @xmath270 @xcite . hence , for typical parameters , @xmath271 , where @xmath272 is the magnetic shear . thus , taes have a two - scale radial structure , the larger scale corresponding to the enveloppe of the tae . in our analysis , we assume that the number of @xmath35 harmonics involved is small enough to consider resonances one by one , as isolated @xmath34 , @xmath35 mode . the latter hypothesis is reasonable for sufficiently core - localised , low-@xmath34 taes . we must keep in mind , though , that high-@xmath34 taes are likely to be destabilized in future devices such as iter , in which case it may be necessary to take into account multiple - wave resonances . the evolution of the distribution @xmath273 of energetic ions is described in 3d configuration space by the kinetic equation ( [ eq:3d_kinetic ] ) , with the perturbed hamiltonian eq . ( [ eq : perturbation_in_aa ] ) . in the following , we reduce the problem to a 1d hamiltonian system , by considering a single @xmath34 , @xmath35 mode . formally , the resonant phase - space surface , @xmath274 , is defined by a function @xmath275 . the resonance condition , @xmath276 where @xmath277 , is satisfied on the resonant phase - space surface . once the perturbed hamiltonian has been put in the form of eq . ( [ eq : perturbation_in_aa ] ) , we can reduce the problem to one action and one angle @xcite , by performing a canonical transformation @xmath278 with the generating function @xmath279 this procedure yields , [ cols= " > , < , > , < " , ] [ tab : params ] , reproduced from figs . 3 and 4 of ref . @xcite , normalized to @xmath280 , to which we superpose a horizontal segment at the tae linear frequency , and a vertical double - arrow , which represents the extent of chirping . ( a ) at @xmath281 , @xmath282khz . ( b ) at @xmath283 , @xmath284khz . ] in jt-60u , taes are destabilized by a negative ion - based neutral beam ( n - nb ) , which injects deuterons at @xmath285 kev . in the discharge e32359 , around @xmath42 s , fast - fs modes have been identified as @xmath286 and @xmath287 taes @xcite . in the spectrogram shown in fig . [ fig : e32359](a ) , we measure @xmath288 khz , @xmath289 , @xmath290 , and @xmath291 ( on average ) . frequency sweeps between @xmath292 and @xmath293 khz . by comparing these frequencies with the saw continuum gap in fig [ fig : continuum ] , it looks as if up - chirping was extending slightly into the continuum . however , the above continuum was estimated by assuming concentric circular flux surfaces , and a radial gradient of shafranov shift can significantly increase the gap width . unfortunately , current profiles are not available for this shot , forbidding more precise estimation of the continuous spectrum . however , there is a shot with similar background plasma parameters , e36378 , for which current profiles are available and the continuum has been calculated @xcite . in fig . [ fig : continuum_e36378 ] , we superpose the extent of chirping , measured in a magnetic spectrogram , to the saw continuum calculated in the reference . at @xmath281s , frequency sweeps between @xmath294 and @xmath295 khz , while the continuum is broken between @xmath296 and @xmath297 khz . at @xmath283s , frequency sweeps between @xmath292 and @xmath298 khz , while the continuum is broken between @xmath299 and @xmath300 khz . in both cases , the extent of chirping taes is well within the gap . thus we can reasonably assume that chirping lifetime is determined by collision processes , rather than by continuum damping . ( b ) and ( c ) spectrogram of the electric field , where the input parameters of the @xmath0 bb model were chosen to fit the magnetic spectrogram for jt-60u discharge e32359 . a solid curve shows the analytic prediction for chirping velocity and lifetime . ( b ) krook collisions , correction parameter @xmath301 . ( c ) friction - diffusion collisions , correction parameter @xmath302 . ] ( [ eq : gams_from_spectro ] ) and ( [ eq : nua_from_spectro ] ) yield @xmath303 , and @xmath304 . however , a preliminary analysis suggests that the plasma belongs to a regime where @xmath305 , hence we adjust the value of the product @xmath306 to @xmath307 . , where @xmath308 , is not included in this plot . both linear and nonlinear stability threshold are indicated . the chirping quasi - period agrees with the experiment for @xmath309 . the spectrogram for the circled simulation is shown in fig . [ fig : e32359](b ) . ] a scan for this set of parameters is given in fig . [ fig : scane32359 ] . the limits of subcritical regime and non - chirping regime yield @xmath310 , @xmath311 . [ fig : e32359](b ) is the spectrogram for the simulation which is emphasized by a circle in fig . [ fig : scane32359 ] . the features of main chirping events agree with the experimental observation . however , quiescent phases are replaced by many chirping events with amplitude slightly smaller than the major ones . linear parameters estimated from this analysis are shown in tab . [ tab : params ] . our analysis suggests that the tae in this discharge is marginally unstable , with @xmath312 , even though @xmath313 , which is not inconsistent with eq . ( [ eq : gaml_minus_gamd ] ) since @xmath314 . however , these values are inconsistent with estimations that take into account drag and diffusion processes . since the following analysis with drag and diffusion shows much better agreement with the experiment , we imply that the krook model is insufficient to describe nonlinear features related to chirping repetition . + and @xmath315 khz . in these arbitrary units , @xmath316 roughly corresponds to a noise level . the parameters of the simulation are shown in the fourth line of tab . [ tab : params ] . for the simulation , to avoid hiding experimental data , we show the amplitude of perturbations ( the enveloppe ) instead of the perturbations themselves . ] a first scan in ( @xmath317 , @xmath318 ) yields an estimation of the correction parameter , @xmath319 . then eqs . ( [ eq : approx_gaml ] ) , ( [ eq : approx_gamd ] ) and ( [ eq : approx_nud ] ) yield @xmath320 , @xmath321 , and @xmath322 . we perform a second scan , which consists of a series of @xmath323 simulations in the domain ( @xmath324 , @xmath325 ) , where @xmath326 and @xmath6 are constrained by eqs . ( [ eq : chirping_lifetime_dragdiff ] ) and ( [ eq : gams_from_spectro ] ) . the only repetitive chirping solution with @xmath327 we found is shown in fig . [ fig : e32359](c ) . we verify that chirping features measured in this simulation fit the experiment , @xmath328 ( @xmath329 for up - chirping , @xmath330 for down - chirping ) , @xmath331 ( @xmath332 for up - chirping , @xmath333 for down - chirping ) , and @xmath334 . estimated linear parameters are shown in tab . [ tab : params ] . to validate this analysis , we compare the amplitude of perturbations in fig . [ fig : e32359_amplitude_dragdiff ] . we obtain a quantitative agreement , with a growth rate of @xmath335 , and a decay rate of @xmath336 . as an independent validation , we now estimate the values of @xmath317 and @xmath337 from background plasma parameters . in the discharge e32359 around @xmath42 s , the resonant surface of the @xmath286 and @xmath287 tae is located around @xmath338 m. the magnetic shear is estimated from the @xmath68 profile @xcite , @xmath339 . the deuteron plasma has the following characteristics , @xmath27 t , @xmath28 m , and the tangential radius of the n - nb is @xmath340 m. at @xmath338 m , @xmath341 m@xmath342 , and @xmath343 kev . we take into account carbon impurities with @xmath344 . with these equilibrium measurements , eqs . ( [ eq : nuf]-[eq : nud ] ) yield @xmath345 and @xmath346 . we obtain a quantitative agreement for @xmath337 , which further validates our fitting procedure . however , @xmath317 was underestimated by @xmath347 compared to the latter estimation from background plasma parameters . though error bars in experimental data may account for this discrepancy , it is also possible that our model misses some mechanism that would enhance friction . note that electrons account for @xmath348 of @xmath349 , which reflects a high alfvn velocity , while impurities account for @xmath350 of @xmath351 , which is consistent with the fact that pitch - angle scattering is more effective with heavier particles . this observation suggests that impurities tend to reduce the ratio @xmath352 , which reduces the frequency of ae activity . overall , our fitting procedure with drag and diffusion shows quantitative agreement for the time - evolution of perturbation , for an independent estimation of the linear drive in the case of mast , and for an independent estimation of collision frequencies in the case of jt-60u . on the other hand , our fitting procedure with krook collisions give similar linear rates only in mast case , and in general we could not clearly reproduce periodic chirping with quiescent phases . thus we infer that a fitting procedure of chirping features to estimate linear properties of background plasma is valid , provided that drag and diffusion are taken into account . resonant interactions between nbi - induced far passing energetic ions and taes were described by a hamiltonian perturbation in guiding - center angle - action variables . by reducing the latter hamiltonian , a fokker - planck collision operator , and external damping processes to a new , 2d phase - space , we showed how the input parameters of the bb model are quantitatively related to plasma parameters and characteristics of the tae . we developed a kinetic code to solve the initial - value bb model . cobbles was verified by checking conservation properties , benchmarked against numerical simulations in former works , and validated against well - known linear and nonlinear theories . the feasibility of long - time simulations for a low-@xmath5 distribution hinged upon quick convergence and strong numerical stability of the cip - csl scheme . with both @xmath0 and full-@xmath1 versions of cobbles , we explored theory in several parameter regimes , namely steady - state , periodic , chaotic , chirping , and subcritical . we performed a scan of the nonlinear evolution of electric field in the whole ( @xmath6 , @xmath353 ) parameter space . a new diagnostics allowed us to identify the chirping region . although holes and clumps were not expected to appear when @xmath354 , we found that the frequency sweeping region can expand to a low external dissipation regime , around @xmath355 . numerical results display good quantitative agreements with theory in several regimes . the limits of validity correspond to the assumptions used in theory . a perturbative numerical approach which does nt take into account the kinetic response of the bulk may feature spurious agreement outside of the validity limits when the resonant region reaches a non negligible portion of bulk particles . we found a regime of quasi - periodic chirping with both krook and drag / diffusion collision operators . since quantitative agreement with theory suggests the predictability of nonlinear chirping characteristics based on fundamental linear kinetic parameters , the latter may be estimated in the opposite way from chirping data in experiments . more precisely , chirping velocity and lifetime yield two relations among @xmath5 , @xmath6 , and collision frequencies ; and a fitting of @xmath356 yields an estimation of remaining unknowns . note that major advantages of this technique are 1 . kinetic parameters in the core of the plasma estimated only from a spectrogram of magnetic fluctuations measured at the edge , without expensive kinetic / mhd calculations nor detailed core diagnostics , and 2 . unified treatments of supercritical and subcritical aes . we showed that diffusion is essential to reproduce quiescent phases observed in experiments between chirping events , and drag is required to observe repetitive chirping , since drag allows the distribution to recover in a reasonable time . we confronted this procedure by analyzing aes on mast and jt-60u . we found quantitative agreement with measured magnetic fluctuations for the growth and decay of chirping structures , quantitative agreement with an estimation of the linear drive based on measured magnetic fluctuation amplitude in the case of mast , and qualitative agreement with collision frequencies estimated from experimental background measurements in the case of jt-60u . in the latter estimations , impurities , which were not included in estimations of ref . @xcite , account for the main part of velocity diffusion . in both cases , our analysis suggests that taes belong to a regime which is relatively far from marginal stability , where total growth rate is of the same order as linear drive . accurate estimations of linear drive , damping rate , and overall growth rate , open the way to promising advanced numerical and experimental investigations . 1 . applying the same procedure to dozens of available chirping tae data would produce a database from which useful trends could be extracted . 2 . the estimated growth rates and collision frequencies could be translated in terms of spatial gradient of energetic - particle distribution , assuming a slowing - down distribution in energy , and in terms of coefficients of the 3d fokker - planck collision operator . this work would yield all input parameters of drift - kinetic perturbative 3d simulations that assume a fixed and arbitrary external damping , such as in the hagis code , where drag and diffusion is being implemented . 3 . since @xmath67 is roughly proportional to @xmath357 , where @xmath358 is the energy , it should be possible to control the growth rate by varying the total number of injected high - energy ions . a possible scenario is to start from a nbi experiment with chirping taes , and reproduce the same conditions except for different nbi power @xmath359 at the time of chirping . with a scan in @xmath359 , dependency of @xmath67 on @xmath359 and existence of subcritical taes could be investigated . * _ spectroscopic determination of kinetic parameters for frequency sweeping alfvn eigenmodes _ , m. lesur , y. idomura , k. shinohara , x. garbet , and the jt-60u team , phys . plasmas 17 , 122311 ( 2010 ) @xcite . * _ estimation of kinetic parameters based on chirping alfvn eigenmodes _ , m. lesur , y. idomura , k. shinohara , and x. garbet , proc . of 23rd iaea fusion energy conference ( to appear ) . * _ nonlinear modification of the stability of fast particle driven modes in tokamaks _ , c. nguyen , x. garbet , v. grandgirard , j. decker , z. guimares - filho , m. lesur , h. ltjens , a. merle , and r. sabot , plasma phys . and cont . 52 , 124034 ( 2010 ) @xcite . * _ existence of metastable kinetically driven modes _ , c. nguyen , h. ltjens , x. garbet , v. grandgirard , and m. lesur , phys . 105 , 205002 ( 2010 ) @xcite . * _ reduced model analysis of supercritical and subcritical chirping alfvn eigenmodes _ , m. lesur , y. idomura , k. shinohara , and x. garbet , proc . of 8th bpsi annual meeting , reports of riam , kyushu university , s-5 , 37 ( 2010 ) . * _ fully nonlinear features of the energy beam - driven instability _ , m. lesur , y. idomura , and x. garbet , phys . plasmas 16 , 092305 ( 2009 ) @xcite . * _ estimation of kinetic parameters based on chirping alfvn eigenmodes - effect of drag and diffusion _ , 4th itpa topical meeting on energetic particles , seoul ( october 2010 ) . * _ spectroscopic determination of kinetic parameters for frequency sweeping alfvn eigenmodes _ , 4th itpa topical meeting on energetic particles , garching ( april 2010 ) . * _ estimation of kinetic parameters based on chirping alfvn eigenmodes - application to jt-60u _ , 15th numerical experiment of tokamak ( next ) workshop , kyoto ( march 2010 ) . * _ reduced model analysis of chirping alfvn eigenmodes - application to mast _ , 8th burning plasma simulation initiative ( bpsi ) , kyushu ( december 2009 ) . * _ the energetic beam - driven instability - kinetic nonlinearities and subcritical instability in jt-60u _ , 7th general scientific assembly of the asia plasma and fusion association ( apfa2009 ) and the asia - pacific plasma theory conference ( apptc2009 ) , aomori ( october 2009 ) . * _ nonlinear evolution of frequency sweeping ( chirping ) _ , 5th festival de thorie , aix - en - provence ( july 2009 ) . * _ fully nonlinear features of the energetic beam - driven instability _ , 14th numerical experiment of tokamak ( next ) workshop , kyoto ( march 2009 ) . # 1_#1 # 1_#1 to illustrate the improvements of lie transform perturbation theory compared to classical perturbation theory , let us apply both formulations to a simple mathematical problem , @xmath360 where @xmath153 is a small parameter , with initial conditions @xmath361 and @xmath362 . these are the equations of motion of an hamiltonian system , with hamiltonian @xmath363 in action - angle variables @xmath364 , which are defined by @xmath365 the unperturbed motion is described by @xmath366 and the perturbed system by the total hamiltonian , @xmath367 classical perturbation theory yields a @xmath368-order solution of hamilton s equations , @xmath369 after an expansion in the small parameter @xmath153 , @xmath370 . [ fig : lie_action_energy ] ( a ) and ( c ) show the evolution of action and total energy given by the application eq . ( [ eq : classic_motion ] ) at successive orders . these results are compared with the exact solution obtained by solving the original hamilton s equations with a fourth - order runge - kutta scheme @xcite with a very small time - step width . at small times , the solution given by this method is close to the exact solution , but we rapidly observe a strong secularity effect that makes the average action spuriously shrink or expand . . ] let us now treat the same problem , this time with lie perturbation theory . the fundamental one - form , @xmath371 , can be separated into its equilibrium part and the perturbation , @xmath372 and @xmath373 for @xmath374 . to simplify the fundamental one - form , we change variables from @xmath375 to @xmath376 . following lie perturbation theory , the zeroth - order one - form and the time coordinate remain unchanged , @xmath377 , and @xmath378 . applying eqs . ( [ eq : givenewoneform ] ) , ( [ eq : givegaugescalar ] ) , and ( [ eq : givegeneratingfunctions ] ) , we find the new one - form , gauge scalar , and generating functions , which yield a solution which is valid up to @xmath368-order in @xmath153 . we choose initial conditions such that orbits have a same energy level . at first order , @xmath379 this solution can be obtained in terms of the original coordinates by using the pull - back operator , @xmath380 \;+\ ; o(\epsilon ^2 ) , \label{eq : firstorderanalyticsol3}\\ \action & = & \newaction \;-\ ; \epsilon \dfrac{\newaction^2}{4 } \ , \left [ \dfrac{1}{2 } \cos(4\newangle ) \,-\ , 2 \cos(2\newangle ) \right ] \;+\ ; o(\epsilon ^2 ) . \label{eq : firstorderanalyticsol4}\end{aligned}\ ] ] at second order , @xmath381 and the pull - back operator is , @xmath380 \nonumber\\ & & + \ ; \epsilon ^2 \dfrac{\newaction^2}{512 } \left [ \sin(8\newangle ) \,-\ , 16 \sin(6\newangle ) \,-\ , 4\sin(4\newangle ) \,+\ , 400 \sin(2\newangle)\right ] \;+\ ; o(\epsilon ^3 ) , \label{eq : secondorderanalyticsol3}\end{aligned}\ ] ] @xmath382\nonumber\\ & & + \ ; \epsilon ^2 \dfrac{\newaction^3}{64 } \left [ 2\cos(6\newangle ) \,+\ , 6 \cos(4\newangle ) \,-\ , 42\cos(2\newangle ) \,+\ , 17 \right ] \;+\ ; o(\epsilon ^3 ) . \label{eq : secondorderanalyticsol4}\end{aligned}\ ] ] fig . [ fig : lie_action_energy ] ( b ) and ( d ) show action and total energy for analytic solutions , eq . ( [ eq : firstorderanalyticsol1]-[eq : firstorderanalyticsol4 ] ) and ( [ eq : secondorderanalyticsol1]-[eq : secondorderanalyticsol4 ] ) , with @xmath383 . there is good agreement with the exact solution , without any secularity effect . [ fig : lie_error_vs_epsilon ] shows the relative error in total energy conservation against the small parameter @xmath153 . it is confirmed that the error is one order higher than the order of perturbation analysis . . for small @xmath153 , solid , dotted , and dashed lines scale as @xmath153 , @xmath384 , and @xmath385 , respectively . ] most of linear and nonlinear numerical investigations of taes are based on a hybrid model where energetic particles follow gyrokinetic equations , while background thermal populations are described by a mhd model @xcite . such simulations can exhibit chirping that is qualitatively similar to experiments @xcite . ultimately , the results we obtain in this thesis with our 1d approach should be compared with global gyrokinetic simulations - actually , this should have been an intermediary step before carrying out comparisons with experiments . this appendix summarizes some results of gyrokinetic theory , which could be used in future works . note that the following results are not used within the core of this manuscript . the goal is to investigate a break - down of gyrokinetics when time - scale and length - scale of the perturbation approach the gyromotion time - scale and length - scale , and when the amplitude of perturbation approaches the equilibrium . since we used lie - transform perturbation theory to derive the set of gyrokinetic equations , this provides a second illustration of this technique . let us consider the evolution of a distribution @xmath1 in 6d ( 3d position , 3d velocity ) phase - space @xmath386 , given by a vlasov equation , @xmath387 where @xmath108 is the hamiltonian , and @xmath388 are poisson brackets . this description can be simplified by removing the irrelevant fast gyromotion from the complete motion of charged particles , thus reducing dimensionality to 5d . there are two ways to proceed , * averaging vlasov equation over a gyroperiod , @xmath389 where @xmath222 is the cyclotronic angle , or * finding a coordinate transformation from @xmath386 to @xmath390 , where @xmath1 and @xmath108 are changed to @xmath391 and @xmath392 such that @xmath393 and @xmath392 does not depend on @xmath222 . lie transform provides a modern way of deriving gyrokinetic equations in the latter fashion , which preserves the hamiltonian structure of the initial problem . these conservation properties are essential for robust long - time computations . [ fig : gyrokinetics ] is a schematic summary of the modern derivation of gyrokinetic equations . we develop a numerical simulation to solve the equations of motion for a single ion in both particle coordinates , guiding - center coordinates , and gyrocenter coordinates . the aim is to compare 3 ways of computing the orbit of a single particle . we consider an electrostatic perturbation @xmath214 of frequency and wave vector @xmath44 and @xmath394 , respectively . for the gyrokinetic treatment to be valid , the gyrokinetic ordering @xcite , @xmath395 has to be satisfied . here @xmath396 is the ion cyclotronic frequency , @xmath397 the ion temperature , @xmath398 the ion larmor radius , and @xmath176 a scale - length of variation of equilibrium plasma . as a test problem , we assume an homogeneous magnetic field @xmath399 and a time - independant , single - wave electrostatic perturbation , @xmath400 then , the gyrokinetic ordering is reduced to @xmath401 , and @xmath402 . we normalize length , time , velocity , and electric potential , to debye length @xmath403 , inverse ion plasma frequency @xmath404 , ion thermal velocity @xmath405 , and the ratio @xmath406 respectively . [ [ in - particle - position - coordinates ] ] in particle position coordinates + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + the equations of motion expressed in particle position coordinates are given by newton s equations with lorentz s force , @xmath407 [ [ in - guiding - center - coordinates ] ] in guiding - center coordinates + + + + + + + + + + + + + + + + + + + + + + + + + + + + + we recall the guiding - center variables @xmath217 , @xmath408 the equations of motion expressed in guiding - center coordinates @xcite are given by @xmath409 [ [ in - gyrocenter - coordinates ] ] in gyrocenter coordinates + + + + + + + + + + + + + + + + + + + + + + + + + in ref . @xcite , a complete set of gyrokinetic equations is derived in the homogeneous magnetic field case , based on lie - transform perturbation theory . in the gyrocenter variables @xmath410 , the equations of motion are @xmath411 the first equation yields the velocity of the gyrocenter as a sum of parallel velocity and @xmath412 velocity . the second one shows the effect on parallel acceleration of the electric field . the third one confirms that the new magnetic momentum is an exact invariant . the last one can be ignored in practical gyrokinetic simulations . however , it is evolved in our simulation since it is needed to retrieve guiding - center coordinates from gyrocenter coordinates and compare physical quantities expressed in different sets of coordinates . [ [ test - problem-1 ] ] test problem + + + + + + + + + + + + let the plasma be such that @xmath413 ghz , @xmath414 m.s@xmath415 and @xmath416 @xmath123 m , with a magnetic field amplitude @xmath417 t . then @xmath418 mhz and @xmath419 mm , or @xmath420 and @xmath421 in normalized units . we define two small parameters @xmath422 and @xmath423 . in our test problem , we choose @xmath424 , @xmath425 , @xmath426 . the initial conditions are @xmath427 , and @xmath428 , so that @xmath429 . this set of parameters satisfies the gyrokinetic ordering , @xmath430 [ [ comparison - of - numerical - results - in - several - coordinate - systems ] ] comparison of numerical results in several coordinate systems + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + to compare numerical results between themselves , we transform each coordinate system into guiding - center coordinates . for the particle coordinates we define @xmath431 where @xmath432 guiding - center coordinates are taken as the reference , @xmath433 . finally the guiding - center coordinates are related with the gyrocenter coordinates @xmath434 by the pull - back transform , @xmath435 where we have explicitly written the small parameters as reminders of the order of each term . note that the generating vector for the parallel velocity is one order higher than the others . and @xmath436 . ] and the unperturbed solution @xmath437 ) . simulation with @xmath383 and @xmath436 . ] . ] in order to compare results obtained by the gyrokinetic code with the true orbit of the particle and its guiding - center , we firstly run a numerical simulation with a very small time - step , @xmath436 , where @xmath438 is a gyration period . fig . [ fig : position ] shows the orbit of the particle calculated in position / velocity coordinates , and the orbit of the guiding - center , which overlaps with orbits of both the push - forward of the particle position and the pull - back of the gyrocenter . then we choose a practical time - step width , and compare , in fig . [ fig : errnrj ] , the guiding center hamiltonian calculated in the three coordinates system , @xmath439 we observe a secularity effect in the numerical error of particle position . the gyrocenter hamiltonian , @xmath440 is trivially perfectly conserved . [ [ analysis - of - the - error ] ] analysis of the error + + + + + + + + + + + + + + + + + + + + + , against time - step width . a solid line follows a @xmath441 law , and dashed lines follow a @xmath442 law . two points marked @xmath443 show a break - up of gyrokinetics close to cyclotronic period . ] firstly , we analyse the numerical error . our code uses a fourth - order runge - kutta scheme @xcite . as a consequence , the error between numerical and analytic solutions is proportionnal to @xmath444 . [ fig : errordt5 ] shows the variation of the relative error in the conservation of guiding - center and gyrocenter hamiltonians , calculated after a fixed , long time ( hundred gyration periods ) , with increasing time - step . this plot is consistent with the prediction of numerical error for this numerical scheme . note that the error for each coordinate is proportional to @xmath444 , save the magnetic momentum calculated in gyrocenter coordinates , which is trivially exactly conserved for any time - step width . the curve of gyrokinetic - calculated error crosses the other ones at a fraction of the cyclotronic period , meaning that a gyrokinetic computation becomes rapidly more efficient . however , the points marked @xmath443 show that even when the gyrocenter hamiltonian is precisely conserved , the conservation of guiding - center hamiltonian breaks - down when the time - step width is close to the cyclotronic period , @xmath445 . this is caused by a lack of accuracy of the pull - back transformation of coordinates , coming from a lack of accuracy for large time - step width in the computation of @xmath446 . and @xmath447 are different . ( a ) scan in electric field amplitude @xmath448 . a solid line follows @xmath449 law . simulation parameters are @xmath450 , and @xmath451 . ( b ) scan in @xmath452 . a solid line follows @xmath453 law . simulation parameters are @xmath454 , and @xmath455 . ] . time - step width of simulations is @xmath454 . ] [ fig : errorepek ] shows the variation of the relative error in the conservation of guiding - center and gyrocenter hamiltonians with the small parameters @xmath448 and @xmath447 , for a very small time - step width . [ fig : erroreps ] shows the variation of the relative error in the conservation of guiding - center and gyrocenter hamiltonian with the small parameter @xmath153 , when @xmath456 . to predict the variation of the relative error in the conservation of the hamiltonian ( [ eq : gchamgy ] ) , let us calculate its difference with the gyrocenter hamiltonian , whose error in conservation does not depend on the small parameters , @xmath457 the latter result is consistent with both fig . [ fig : errorepek ] and fig . [ fig : erroreps ] . using a full set of gyrokinetic equations , which is valid up to first order in the small parameter @xmath153 , in the case of an homogeneous magnetic field and a small electrostatic perturbation that satisfies the gyrokinetic ordering , we computed a single charged - particle orbit . we confirmed that the error due to the gyrokinetic reduction is of the order of @xmath384 . this simple test problem shows the accuracy of gyrokinetic equations compared to a direct computation of the particle orbit in position / velocity or guiding - center coordinates . we note that in practical gyrokinetic codes , information about the gyroangle is discarded , because of its inaccuracy and its irrelevancy . to solve the general 1d advection equation , @xmath458 in a conservative form , we evolve both @xmath275 and its integrated value @xmath459 . @xmath460 ( @xmath461 ) is the continuous interpolated solution for @xmath275 ( @xmath459 ) at a time @xmath462 . @xmath463 is the discrete value of @xmath460 at the grid point of coordinate @xmath464 , and @xmath465 @xmath466 is an array which contains the values @xmath463 for every point @xmath35 on a grid point of coordinate @xmath467 . we define the 1d algorithm @xmath468(@xmath469 , @xmath466 , @xmath470 , @xmath471 , @xmath472 , @xmath122 , @xmath473 , @xmath474 ) as follows . for each @xmath35 , * define @xmath475 ; * find the grid point @xmath476 satisfying @xmath477 , and define @xmath478 ; * define the coefficients @xmath479 @xmath480 * advect @xmath459 , @xmath481 where @xmath482 * advect @xmath275 , @xmath483 this 1d algorithm is extended to the 2d phase - space @xmath484 in the following way . @xmath485 is the value of the distribution @xmath1 at the grid point of coordinates @xmath486 , @xmath487 , at a time @xmath462 . we define the density within a cell and the line densities , @xmath488 @xmath489 @xmath490 the first advection in the @xmath491-direction is performed by calling successively , for each @xmath129 , @xmath492 with @xmath493 . similarly , the advection in the @xmath111-direction is performed by calling successively , for each @xmath74 , @xmath494 with @xmath495 . then we repeat the advection in the @xmath491-direction , @xmath496 here , subscripts @xmath497 and @xmath498 were used to designate intermediate steps between @xmath499 and @xmath500 . to avoid spurious leakage of particles , we impose a zero flux at the velocity boundaries by setting @xmath501 + boundary conditions in the velocity distribution are illustrated in fig . [ fig : cipcsl_f_d](a ) , which shows the discretization on @xmath502 grid points of a maxwellian distribution @xmath503 , and its interpolation polynomial @xmath275 . notice two buffer points @xmath504 and @xmath505 . [ fig : cipcsl_f_d](b ) shows the integral function , @xmath506 and its interpolation polynomial @xmath507 . discretization of @xmath205 , which is defined as @xmath508 is included . here we chose a small number of grid points and small cut - off velocities to emphasize border effects . for realistic parameters , the discrepancies between @xmath1 and @xmath275 , and between @xmath509 and @xmath507 are negligible . grid points . ( a ) particle distribution @xmath1 , interpolation polynomial @xmath275 , and discretized values @xmath510 . ( b ) density distribution @xmath509 , interpolation polynomial @xmath507 , and discretized values of grid - point density @xmath511 . inset : zoom on the first points . ] the algorithm we developed to categorize the behavior of each numerical solution is an improved version of the algorithm designed by vann @xcite , with an other way of sorting out chaotic from periodic behavior , a new diagnostics to distinguish chirping from merely chaotic solutions , and where we take into account numerical issues that appear when @xmath5 is smaller . the categorization is based on an analysis of the time - series of normalized electric field energy , @xmath512 , with @xmath513 . firstly , we define the global minimum as @xmath514 , where @xmath515 is the time - duration of the simulation . then we drop the initial transient phase , and extract a time window @xmath516 over which @xmath517 is sampled at a rate @xmath518 . here , @xmath519 is an estimation of the time - duration of the transient phase . within this window , we define the mean value @xmath520 , maximum @xmath521 and minimum @xmath522 , the oscillation amplitude @xmath523 , and the local minima ( maxima ) as points where @xmath517 is smaller ( larger ) than @xmath524 and @xmath525 . as a measure of the periodicity , we compute the two - point correlation function as @xmath526 where , for each correlation window size @xmath527 , @xmath528 @xmath529 is the number of periods included inside the total time - window , and angular brackets represent a time - average over a period , @xmath530 the overall correlation @xmath37 is defined as the maximum of @xmath531 for @xmath532 , where @xmath533 is the shortest period such that @xmath534 . in other words , @xmath37 is the normalized amplitude of the peak in the two - point correlation function corresponding to the dominant frequency . this measure , which is used to sort out chaotic from periodic behavior , is different from the one given in ref . . we also provide a criterion to sort out chirping solutions . we compute the frequency power spectrum of the time - evolution of the electric field at some position , @xmath535 , and normalize the amplitude of the spectrum to its maximum value . at each time , we extract the largest and smallest frequency for which the amplitude in the power spectrum is significant , i.e. larger than a threshold @xmath536 . then , we define @xmath537 as the maximum difference between the largest and smallest frequency , normalized to the plasma frequency . we then proceed to the following decision tree : 1 . [ test0 ] if @xmath538 then damped 2 . else if @xmath539 then chirping 3 . else if @xmath540 then damped 4 . else if @xmath517 is monotonic and @xmath541 then steady - state 5 . else if @xmath517 is monotonically decreasing ( zero local extrema ) then damped 6 . else if each minima ( maxima ) is larger ( smaller ) than the former or @xmath542 or @xmath543 then steady - state 7 . else if @xmath544 then periodic 8 . else if the number of extrema is not less than four then chaotic , where @xmath545 are thresholds that must be carefully adjusted . special care is taken in adjusting @xmath546 empirically so that frequency splitting is not mistaken for frequency sweeping . in this decision tree , the logical test [ test0 ] is an addition to the decision tree given in ref . @xcite . for damped solutions , as the electric field becomes small , the particles experience free streaming , leading to spurious recurrence effects after half a recurrence time @xmath547 @xmath548 @xmath549 . free streaming occurs when @xmath550 , and @xmath551 is chosen to reflect this condition . for the benchmark in [ subs : benchmark ] , this logical step is switched off as the recurrence effect is less problematic for shorter - time simulations . numerical validation of chirping theory , and development of semi - empirical laws for chirping features , both hinge upon systematic quantification of chirping velocity , lifetime , and period or quasi - period . we developed an algorithm to measure features of major chirping events in both full-@xmath1 and @xmath0 cobbles simulations , for both krook and drag / diffusion collisions , except in the dragging regime . the starting point is a spectrogram @xmath552 , such as plotted in fig . [ fig : e32359](b ) or ( c ) , which is obtained from time - series of the electric field at @xmath553 with a moving fourier window of size @xmath474 , and the linear frequency @xmath44 , which is obtained from one of our linear analysis tools described in sec . [ sec : bblin ] . here , @xmath74 is an index of the median time of a fourier window , and @xmath129 is an index of the frequency , where @xmath554 . let us consider upward chirping only . the first step is to identify major chirping branches . a simple approach would be to extract from the spectrogram , at each time step , the local maximum , and try to fit a square root function following maxima whose amplitude exceeds some threshold . however , two or more chirping branches including minor events can easily be confused as one ( minor and major events are not well separated categories , it is difficult to set a threshold to isolate major events ) . trying to start from the tip of a branch and follow it down by jumping to the closest maximum fails for the same reason . the problem with these procedures is that , when we extract maxima , we loose useful information , namely the amplitude of these maxima . the following approach makes use of some additional information . it requires a rough estimation of chirping velocity @xmath555 , and a rough estimation of chirping lifetime @xmath556 , both of which are easily obtained from theory using input parameters of the simulation . first , we initialize a test chirping velocity @xmath557 to @xmath558 . for each time - step @xmath559 of the spectrogram , the algorithm takes the sum @xmath560 of @xmath552 , where @xmath74 starts from @xmath561 , and @xmath562 is such that @xmath563 roughly follows a square - root law with a coefficient given by @xmath557 . we repeat this procedure for each @xmath561 , and for test chirping velocities @xmath564 . a maximum of @xmath560 should indicate the initial time @xmath559 and velocity @xmath557 of a major chirping event . we found this is the case most of the time for data that are analyzed in this work . simultaneously , we extract the maximum @xmath565 reached by @xmath566 during this chirping event . the second step is to identify the tip of chirping . using the estimated chirping velocity and @xmath556 , we deduce its approximate location @xmath567 and @xmath568 . the algorithm , starting from well above @xmath568 and decrementing @xmath129 , searches around @xmath567 for the first value of @xmath566 above a threshold which is given by @xmath569 . this should correspond to the tip of the considered chirping event , @xmath570 and @xmath571 . since the algorithm is sometimes mistaken , we go on decrementing @xmath129 , while following the first local maximum to the left ( left meaning smaller time here ) . when we reach a @xmath129 such that @xmath572 , we check that @xmath74 is close to @xmath573 . then the lifetime is given by @xmath574 . otherwise the chirping event is discarded . repeating the above steps while avoiding the time region @xmath575 yields velocity and lifetime of a significant number of major chirping events . finally the chirping period is simply obtained by extracting the maximum in the fourier spectrum of electric field time - series . the whole procedure requires only a few seconds on one typical laptop processor , even for long - time simulations ( @xmath576 ) . the same algorithm is used to measure chirping features in experimental data . in this case , the starting point is a spectrogram of magnetic perturbations measured by a mirnov coil at the edge of the plasma , such as fig . [ fig : e32359](a ) , the linear frequency @xmath44 and a rough estimation of chirping velocity , and of chirping lifetime , which are directly measured on the spectrogram . d. borba , h. l. berk , b. n. breizman , a. fasoli , f. nabais , s. d. pinches , s. e. sharapov , d. testa , and the efda - jet workprogramme . modelling of alfvn waves in jet plasmas with the castor - k code . , 42:10291038 , august 2002 . a. fukuyama and t. akutsu . kinetic global analysis of alfvn eigenmodes in toroidal plasmas . in _ proceedings of the 19th iaea fusion energy conference , lyon , 2002 _ , volume th / p3 - 14 , pages 15 . iaea , vienna , 2003 . a. fasoli , d. borba , g. bosia , d. j. campbell , j. a. dobbing , c. gormezano , j. jacquinot , p. lavanchy , j. b. lister , p. marmillod , j .- moret , a. santagiustina , and s. sharapov . direct measurement of the damping of toroidicity - induced alfvn eigenmodes . , 75(4):645648 , jul 1995 . a. fasoli , b. n. breizman , d. borba , r. f. heeter , m. s. pekker , and s. e. sharapov . nonlinear splitting of fast particle driven waves in a plasma : observation and theory . , 81:55645567 , decembre 1998 . a. fasoli , d. borba , b. breizman , c. gormezano , r. f. heeter , a. juan , m. mantsinen , s. sharapov , and d. testa . fast particles - wave interaction in the alfvn frequency range on the joint european torus tokamak . , 7:18161824 , may 2000 . gorelenkov , s. bernabei , c.z . cheng , k.w . hill , r. nazikian , s. kaye , y. kusama , g.j . kramer , k. shinohara , t. ozeki , and m.v . stability properties of toroidal alfvn modes driven by fast particles . , 40(7):1311 , 2000 . x. garbet , g. dif - pradalier , c. nguyen , p. angelino , y. sarazin , v. grandgirard , p. ghendrih , and a. samain . a minimal collision operator for implementing neoclassical transport in gyrokinetic simulations . in olivier sauter , xavier garbet , and elio sindoni , editors , _ proceedings of aip conference on theory of fusion plasmas _ , volume 1069 , pages 271276 . aip , melville , ny , 2008 . y. kusama , g. j. kramer , h. kimura , m. saigusa , t. ozeki , k. tobita , t. oikawa , k. shinohara , t. kondoh , m. moriyama , f. v. tchernychev , m. nemoto , a. morioka , m. iwase , n. isei , t. fujita , s. takeji , m. kuriyama , r. nazikian , g. y. fu , k. w. hill , and c. z. cheng . characteristics of alfvn eigenmodes , burst modes and chirping modes in the alfvn frequency range driven by negative ion based neutral beam injection in jt-60u . , 39:18371843 , novembre 1999 . k. g. mcclements , m. p. gryaznevich , s. e. sharapov , r. j. akers , l. c. appel , g. f. counsell , c. m. roach , and r. majeski . physics of energetic particle - driven instabilities in the start spherical tokamak . , 41:661678 , may 1999 . r. nazikian , g. y. fu , s. h. batha , m. g. bell , r. e. bell , r. v. budny , c. e. bush , z. chang , y. chen , c. z. cheng , d. s. darrow , p. c. efthimion , e. d. fredrickson , n. n. gorelenkov , b. leblanc , f. m. levinton , r. majeski , e. mazzucato , s. s. medley , h. k. park , m. p. petrov , d. a. spong , j. d. strachan , e. j. synakowski , g. taylor , s. von goeler , r. b. white , k. l. wong , and s. j. zweben . alpha - particle - driven toroidal alfvn eigenmodes in the tokamak fusion test reactor . , 78(15):29762979 , apr 1997 . c nguyen , x garbet , v grandgirard , j decker , z guimares - filho , m lesur , h ltjens , a merle , and r sabot . nonlinear modification of the stability of fast particle driven modes in tokamaks . , 52(12):124034 , 2010 . takashi nakamura , ryotaro tanaka , takashi yabe , and kenji takizawa . exactly conservative semi - lagrangian scheme for multi - dimensional hyperbolic equations with directional splitting technique . , 174(1):171207 , 2001 . m. osakabe , s. yamamoto , k. toi , y. takeiri , s. sakakibara , k. nagaoka , k. tanaka , k. narihara , and the lhd experimental group . experimental observations of enhanced radial transport of energetic particles with alfvn eigenmode on the lhd . , 46(10):s911 , 2006 . s. d. pinches , l. c. appel , j. candy , s. e. sharapov , h. l. berk , d. borba , b. n. breizman , t. c. hender , k. i. hopcraft , g. t. a. huysmans , and w. kerner . the hagis self - 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the achievement of sustained nuclear fusion in magnetically confined plasma relies on efficient confinement of alpha particles , which are high - energy ions produced by the fusion reaction . such particles can excite instabilities in the frequency range of alfvn eigenmodes ( aes ) , which significantly degrade their confinement and threatens the vacuum vessel of future reactors . in order to develop diagnostics and control schemes , a better understanding of linear and nonlinear features of resonant interactions between plasma waves and high - energy particles , which is the aim of this thesis , is required . in the case of an isolated single resonance , the description of ae destabilization by high - energy ions is homothetic to the so - called berk - breizman ( bb ) problem , which is an extension of the classic bump - on - tail electrostatic problem , including external damping to a thermal plasma , and collisions . a semi - lagrangian simulation code , cobbles , is developed to solve the initial - value bb problem in both perturbative ( @xmath0 ) and self - consistent ( full-@xmath1 ) approaches . two collision models are considered , namely a krook model , and a model that includes dynamical friction ( drag ) and velocity - space diffusion . the nonlinear behavior of instabilities in experimentally - relevant conditions is categorized into steady - state , periodic , chaotic , and frequency - sweeping ( chirping ) regimes , depending on external damping rate and collision frequency . the chaotic regime is shown to extend into a linearly stable region , and a mechanism that solves the paradox formed by the existence of such subcritical instabilities is proposed . analytic and semi - empirical laws for nonlinear chirping characteristics , such as sweeping - rate , lifetime , and asymmetry , are developed and validated . long - time simulations demonstrate the existence of a quasi - periodic chirping regime . although the existence of such regime stands for both collision models , drag and diffusion are essential to reproduce the alternation between major chirping events and quiescent phases , which is observed in experiments . based on these findings , a new method for analyzing fundamental kinetic plasma parameters , such as linear drive and external damping rate , is developed . the method , which consists of fitting procedures between cobbles simulations and quasi - periodic chirping ae experiments , does not require any internal diagnostics . this approach is applied to toroidicity - induced aes ( taes ) on jt-60 upgrade and mega - amp spherical tokamak devices , which yields estimations of local kinetic parameters and suggests the existence of taes relatively far from marginal stability . the results are validated by recovering measured growth and decay of perturbation amplitude , and by estimating collision frequencies from experimental equilibrium data .

the bethe ansatz is a technique which is based upon the quantum mechanical description of a many particle system by a wave function . the interaction of the individual particles is assumed to be relativistic , short - range and characterized by a factorizable scattering matrix . the boundary condition for the many particle wave function leads to what is commonly referred to as the bethe ansatz equation , which provides the quantization condition for possible momenta of this system . taking the thermodynamic limit of this equation , that is taking the size of the quantizing system to infinity , leads to the so - called thermodynamic bethe ansatz ( tba ) . the origins of this analysis trace back to the seminal papers by yang and yang @xcite and the technique has been refined and applied to different situations in numerous works [ 2 - 6 ] thereafter . the tba constitutes an interface between massive integrable models and conformal field theories . one may extract different types of information from it , where the ultraviolet behaviour , i.e. ultimately the central charge of the conformal field theory , is the most accessible . in the derivation of the tba - equation the underlying statistical interaction ( also called exclusion statistics ) is usually taken to be either of bosonic or fermionic type . seven years ago haldane @xcite proposed a generalized statistics based upon a generalization of pauli s exclusion principle . this type of statistics ( anyonic ) has many important applications , in particular in the description of the fractional quantum hall effect @xcite . the main purpose of this manuscript is to implement systematically the haldane statistics into the analysis of the thermodynamic bethe ansatz . hitherto , attempts in this direction @xcite were mainly based on the consideration of particular statistical interaction which only involves one species , like the calogero - sutherland model @xcite . our approach will cover a general choice of statistical interaction described by some , in general non - diagonal , matrix @xmath0 . we put particular emphasis on the ultraviolet region , which corresponds to the high temperature regime . we also continue our investigation started in @xcite and clarify the role of the anyonic s - matrix ( [ ans ] ) in the context of the tba . we formulate a macroscopical equivalence principle in the sense that the macroscopical nature of a multi - particle system is only governed by the combination ( [ inva ] ) of the dynamical- and statistical interactions . this means in particular that two multi - particle systems differing on the microscopical level , i.e. in the s - matrix , may be made macroscopically equivalent by tuning the statistical interaction . our manuscript is organized as follows : in section 2 we recall the derivation of several thermodynamic quantities from haldane statistics . in section 3 we derive the thermodynamic bethe ansatz equation for a multi - particle system in which the statistical interaction is governed by haldane statistics . in section 4 we argue that certain multi - particle systems may be transformed into macroscopically equivalent systems by tuning the statistical- and the dynamical interaction . in section 5 we demonstrate that certain scattering matrices , leading to equivalent thermodynamical systems differ only by cdd - ambiguities and comment on the ambiguity in choosing a particular statistical interaction . in section 6 we discuss the ultraviolet limit of the generalized tba - equation . in section 7 we derive y - systems related to generalized statistics . in section 8 we illustrate our general statements by some explicit examples . our conclusions are stated in section 9 . the object of our consideration is a multi - particle system containing @xmath1 different species confined to a finite region of size @xmath2 . we denote by @xmath3 the number of particles , by @xmath4 the dimension of the fock - space related to the species @xmath5 and by @xmath6 the number of available states ( holes ) before the @xmath7-th particle has been added to the system . when treating bosons the number of available states naturally equals the total dimension of the fock space , i.e. @xmath8 , whereas when treating fermions there will be restrictions due to pauli s exclusion principle and one has @xmath9 . with these relations in mind the total dimension of the hilbert space may be written for both cases as @xmath10 conventionally one employs in ( [ wahr ] ) the fock - space dimension rather than the number of available states before the @xmath7-th particle has been added to the system . however , besides being a unified formulation , equation ( [ wahr ] ) has the virtue that it allows for a generalization to haldane statistics . by introducing a statistical interaction @xmath11 haldane @xcite proposed the following generalized pauli exclusion principle @xmath12 relation ( [ pauli ] ) means that the number of available states should be regarded as a function of the particles present inside the system . in this proposal a statistical interaction between different particle species is conceivable . in the bosonic case there will be no restriction such that @xmath13 , whereas in the fermionic case the number of available states reduces by one if a particle is added to the system , hence one chooses @xmath14 one assumes @xcite , that the total dimension of the hilbert space is still given by ( [ wahr ] ) , where the quantities involved are related to each other by ( [ pauli ] ) . we now want to analyze the multi - particle system in its thermodynamic limit , that is we let the size of the confining region approach infinity , @xmath15 . it is then a common assumption that the ratio of the particle ( hole or state ) numbers over the system size @xmath2 remains finite . for the fraction of particles ( holes or states ) of species @xmath5 with rapidities between @xmath16 and @xmath17 it is convenient to introduce densities @xmath18 the rapidity @xmath19 parameterizes as usual the two - momentum @xmath20 . integration of the generalized pauli exclusion principle ( [ pauli ] ) then yields a relation between the different types of densities @xmath21 the constant of integration has been identified with the fock space dimension . the reason for this identification is based on fact that in this way one recovers for @xmath13 and @xmath22 the usual bosonic and fermionic relations , respectively . notice that in the finite case the constant is in general slightly different from @xmath4 , for instance for fermionic statistics it has to be chosen as @xmath23 in order to recover the relation @xmath9 . however , in the thermodynamic limit this difference is negligible . let us remark , that equation ( [ dichte ] ) suggests from a physical point of view that @xmath0 should be non - negative . however , if there are additional symmetries then this requirement can be weakened . for instance for two conjugate particles , say @xmath5 and @xmath24 ( see section 8 for examples ) , one naturally assumes that @xmath25 , such that only the combination @xmath26 has to be taken non - negative . we are now in the position to construct further thermodynamic quantities . first of all we may sum up all contributions from occupied states in order to obtain the total energy @xmath27 = l\sum\limits_{i=1}^{l}\int\limits_{-\infty } ^{\infty } d\theta \rho _ { i}^{r}(\theta ) m_{i}\cosh \theta \quad . \label{ener}\ ] ] furthermore , we obtain from ( [ wahr ] ) , upon using stirling s formula @xmath28 , ( [ d1])-([d3 ] ) and ( [ dichte ] ) , the entropy @xmath29 as a functional of the particle- and fock - space density @xmath30 = kl\sum\limits_{i=1}^{l}\int\limits_{-\infty } ^{\infty } d\theta \left [ ( \rho _ { i}-g_{ij}\rho _ { j}^{r})\ln \left ( \frac{\rho _ { i}+h_{ij}\rho _ { j}^{r}}{\rho _ { i}-g_{ij}\rho _ { j}^{r}}\right ) + \rho _ { i}^{r}\ln \left ( \frac{\rho _ { i}+h_{ij}\rho _ { j}^{r}}{\rho _ { i}^{r}}\right ) \right ] \quad . \label{entro}\ ] ] we introduced here @xmath31 and use the sum convention ( sum over j ) to avoid bulky expressions . @xmath32 is boltzmann s constant . according to the fundamental postulates of thermodynamics the equilibrium state of a system is found by minimizing the free energy @xmath33 . hence , keeping the temperature constant we may obtain the equilibrium condition by minimizing @xmath34 = e\left [ \rho ^{r}\,\right ] -ts\left [ \rho , \rho ^{r}\,\right ] $ ] with respect to @xmath35 . the equilibrium condition reads @xmath36 so far we did not provide any information about the admissible momenta in the system , which are restricted by the boundary conditions . boundary conditions may be accounted for by the bethe ansatz equations . recall that the bethe ansatz equation is simply the equation which results from taking a particle in the multi - particle wave function on a trip through the whole system @xcite . the particle will scatter with all other particles in the system , described by a factorizable s - matrix , such that @xmath37 has to hold for consistency @xcite . to simplify notations we may assume here that the scattering matrix is diagonal , such that the subscripts only label particle species . this set of transcendental equations determines which rapidities are admissible in the system due to the quantization as a result of restricting the size of the system . taking the logarithmic derivative of the bethe ansatz equation ( [ ba ] ) and employing densities as in ( [ d1 ] ) and ( [ d2 ] ) one obtains ( see for instance @xcite , @xcite or @xcite for more details ) @xmath38 here we introduced as usual the notation @xmath39 and denote the convolution by @xmath40 @xmath41 . the equilibrium condition ( [ equ ] ) together with ( [ bou ] ) yields the desired thermodynamic bethe ansatz equation for a system in which statistical interaction is governed by haldane statistics @xmath42 we use here the abbreviations @xmath43 and @xmath44 in the derivation of ( [ bftba ] ) we assumed that @xmath45 . we assume that @xmath46 is symmetric is symmetric in @xmath19 ( due to ( [ uni ] ) ) , this is equivalent to the assumption that ( [ bftba ] ) may be solved iteratively ( see e.g. @xcite ) . ] in the rapidity throughout the manuscript . in general one is only able to solve equations ( [ bftba ] ) numerically as we demonstrate in section 8 . in the formulation of the tba - equation of bosonic or fermionic type , it is common to introduce here as an additional quantity the so - called pseudo - energies @xmath47 in general one may employ @xmath48 for this purpose . for the finite case the same relation was obtained by wu @xcite , there however , the quantity @xmath49 has a slightly different meaning . clearly it is not possible to give a general solution of ( [ id1 ] ) . however , for the bosonic and fermionic case it is solved easily , we obtain @xmath50 and @xmath51 . substitution of these solutions into equations ( [ bftba ] ) turns them into the well - known tba - equations of bosonic and fermionic type @xcite , respectively . with ( [ dichte ] ) the ratios of the related particle- and fock - space densities @xmath52 become the usual bose - einstein ( upper sign ) and fermi - dirac ( lower sign ) distributions . from our point of view it does not seems to be necessary to introduce pseudo - energies and one should rather view @xmath53 as a more fundamental entity . in addition one avoids the problem of solving ( [ id1 ] ) . from a numerical point of view however , it appears sometimes useful to formulate the tba - equation in different variables . we now substitute back the equilibrium condition into the expression for the free energy and obtain together with the general expressions for the total energy ( [ ener ] ) and the entropy ( [ entro ] ) , the generalized thermodynamic bethe ansatz equation ( [ bftba ] ) and ( [ bou ] ) @xmath54 the relation between the free energy and the finite size scaling function is well - known to be @xmath55 @xcite . as usual we now identify the temperature with the inverse of one radial size of a torus @xmath56 and choose now boltzmann s constant to be one . then @xmath57 once more for @xmath50 and @xmath51 we recover the well - known expressions for the scaling functions of bosonic and fermionic statistics . in the ultraviolet limit the scaling function becomes the effective central charge of a conformal field theory @xcite , i.e. @xmath58 . here @xmath59 is the usual conformal anomaly and @xmath60 denotes the lowest conformal dimension @xcite . to summarize : for a given statistical interaction ( [ pauli ] ) and dynamical interaction described by a factorizable scattering matrix , we may solve in principle the generalized thermodynamic bethe ansatz equation ( [ bftba ] ) for @xmath49 . this solution together with the knowledge of the mass spectrum of the theory , allows ( up to a one dimensional integral which may always be carried out by simple numerics ) the calculation of the entire scaling function . from a thermodynamic point of view , systems which have the same expressions for the free energy show the same behaviour . hence multi - particle systems which possess the same scaling function over the entire range of the scaling parameter @xmath61 are to be considered as equivalent . this implies that two multi - particle systems are equivalent , if the mass spectra and the quantities @xmath62 are identical . as a consequence of this we may achieve that two systems equal each other from a macroscopical point of view , despite the fact that they involve different scattering matrices describing the dynamical particle interaction . the apparent difference can be compensated by a different choice of the underlying statistical interaction . considering for instance the well - known tba - equations of bosonic- and fermionic type ( see for instance @xcite ) involving @xmath63 and @xmath64 , respectively , we observe that @xmath65 transforms both equations into each other . the question of whether relations between two scattering matrices leading to ( [ lodiff ] ) are at all conceivable immediately comes to mind . such relations emerge in several places . for example in @xcite the authors assume @xmath66 the function @xmath67 was taken to be the usual step - function , with the property that @xmath68 , such that @xmath69 and @xmath70 only differ at the origin of the complex rapidity plane . this modification was necessary in order to extend the validity of certain identities ( ( 2.18 ) in @xcite leading to eq . ( [ rad ] ) below ) involving the scattering matrices of ade - affine toda field theories ( see for instance @xcite ) , i.e. @xmath69 , also to the origin . in particular , in some special cases these identities become equal to the bootstrap equations . a further motivation to introduce ( [ ss ] ) was to derive so - called y - systems proposed by zamolodchikov ( last ref . in @xcite ) for ade - affine toda field theories . in this case the system which involves @xmath69 with fermionic statistical interaction is equivalent to the system involving @xmath70 with bosonic statistical interaction . as a further example we may also consider a system in which the dynamical interaction is described by the scattering matrix @xmath71 , where @xmath72 denotes the coupling constant and @xmath73 , of the calogero - sutherland model @xcite with a statistical interaction of bosonic type , i.e. @xmath74 . this system is equivalent to a system with a constant s - matrix , e.g. @xmath75 , and a statistical interaction of the form @xmath76 in general we have the following equivalence principle . multi - particle systems , involving quantities such that the relation @xmath77 holds and the masses for the same species are identical , are thermodynamically equivalent . we now want to elaborate on the question in which sense the scattering matrices leading to ( [ trans ] ) differ . the analysis of analytic properties of the scattering matrix leads to a set of consistency equations , which have to be satisfied by any s - matrix related to integrable models in 1 + 1 dimensions . these equations are so restrictive , that they determine the s - matrices of a particular model up to what is usually referred to as cdd - ambiguities @xcite . in this section we argue that certain s - matrices related to each other in such a way , that they lead to ( [ trans ] ) , differ precisely by such ambiguities . a scattering matrix @xmath69 is usually assumed to be a meromorphic function in the strip @xmath78 . this region is considered as physical , meaning that all singularities occurring in this sheet acquire a physical interpretation . the scattering matrix in ( [ ba ] ) is usually regarded as the one which results from an analysis of the so - called bootstrap equations @xmath79 equation ( [ uni ] ) is a result of unitarity and analytic continuation , ( [ cross ] ) a consequence of crossing invariance and ( [ boot ] ) ( strictly speaking this is the boostrap equation ) expresses the factorization property for the fusing process @xmath80 . the so - called fusing angles @xmath81 are specific to each model depending on the mass spectrum . it was found in @xcite that the most general solution to these consistency equations will always be of the form @xmath82 where @xmath83 is a set of complex numbers which characterizes a particular model . when particles are not self - conjugate one should replace @xmath84 by @xmath85 in ( [ allgsol ] ) . there is however the freedom to multiply these expressions with a so - called cdd - ambiguity @xcite ( also of the form ( [ allgsol ] ) , but related to a different set @xmath86 ) , which satisfies by itself all the consistency requirements without introducing any additional poles into the physical sheet . a well - known example for such an ambiguity are for instance the coupling constant dependent blocks . one seeks solutions of the general form ( [ allgsol ] ) involving two sets @xmath83 and @xmath86 such that the product related to the set @xmath83 ( the so - called minimal s - matrix ) already closes the bootstrap and accounts for the whole particle spectrum independent of the coupling constant . then the additional factors related to @xmath86 constitute a cdd - ambiguity depending on the coupling constant @xmath87 in such a way , that in the limit @xmath88 ( in theories which admit duality also @xmath89 ) the s - matrix becomes free , that is one . as a particular case of two s - matrices related to each other such that they may lead to an equation of the type ( [ trans ] ) we will now consider @xmath90 which we discussed in @xcite . similarly as in @xcite we choose @xmath68 . here the @xmath91 are related to the asymptotic phases of the s - matrix @xmath69@xmath92 the asymptotic phases are well defined , since the limit @xmath93 of ( [ allgsol ] ) does not depend on the imaginary part of @xmath19 . this property is in particular needed to obtain ( [ bootph ] ) . the transformation ( [ ans ] ) compensates the asymptotic phases and creates a non - trivial phase at @xmath94 , i.e. the anyonic situation . it was argued @xcite , that from a physical point of view , s - matrices which possess a non - trivial asymptotic phase should be regarded rather as auxiliary objects . scattering matrices of the type ( [ ans ] ) should be considered as the genuine physical quantities , since they lead to the correct physical properties , including the exchange statistics . we shall demonstrate that the system of equations ( [ uni])-([boot ] ) does not have to be altered for the anyonic matrix @xmath95 . for this purpose we will first derive some properties concerning the phases . taking the limit @xmath96 @xmath97 in ( [ uni])-([boot ] ) yields immediately several relations between the asymptotic phases @xmath98 with @xmath99 being some integers . using now these relations for the phases together with the fact that @xmath69 satisfies the consistency equations ( [ uni])-([boot ] ) , it is straightforward to derive the related equations for the anyonic scattering matrix @xmath70@xmath100 comparing @xmath69 and @xmath70 , we conclude , taking ( [ uniph ] ) into account , that the additional factor in ( [ ans ] ) has altered the behaviour at the imaginary axis of the rapidity plane only up to a sign . thus @xmath69 and @xmath70 differ by a cdd - factor . it is straightforward to generalize the previous argument to the case when the scattering matrix is non - diagonal , such that in addition to ( [ uni])-([boot ] ) one also has to satisfy the yang - baxter equation as a consequence of factorization . in this subsection we recall the argument which leads to a particular choice of the statistical interaction . in general one considers the value of the scattering matrix at @xmath101 in order to deduce the symmetry properties of the bethe wave function . then together with the a priori ( or e.g. from a lagrangian ) knowledge of the nature of the particles one deduces the statistical interaction . for example for @xmath102 the bethe wave function is antisymmetric . if in this case one describes bosons , one is forced to choose a fermionic statistical interaction . however , this way of arguing seems somewhat ambiguous as a simple example demonstrates . considering for instance a system in which the dynamical interaction is described by the affine toda scattering matrix , one usually selects @xcite fermionic statistics due to the fact that @xmath103 . in the limit @xmath88 ( because of strong - weak duality one may also take @xmath89 ) the theory becomes free and one obtains @xmath104 . using now the same arguments one has to deduce , from the symmetry of the bethe wave function and the fact that one still describes bosons , that the statistical interaction has to be bosonic . concerning the scaling function there is no problem here since in both cases we obtain the same ultraviolet limit . however , there is a change in the statistics . the apparent paradox is resolved by making use of the macroscopical equivalence . using the scattering matrix ( [ ss ] ) instead one has now @xmath105 . making then use of the bosonic - fermionic transformation ( [ lodiff ] ) we obtain by means of the same arguments a unique , that is bosonic , statistical interaction for the entire range of the coupling constant @xmath87 . scattering matrices related to each other as in ( [ ans ] ) play a distinguished role in this context since they only differ by a cdd - ambiguity as argued in the previous section . considering such expressions the relation between the corresponding quantities @xmath106 and @xmath107 are fixed . in this case we achieve thermodynamical equivalence by demanding @xmath108 we may consider a few examples . for instance in the case of affine toda field theory we have @xmath109 @xcite , such that @xmath110 , which is a transformation from fermionic exclusion statistics to bosonic one . in case we only consider the minimal part of the scattering matrix for ade - affine toda field theory we obtain from the asymptotic behaviour observed in @xcite , i.e. @xmath111 , that is @xmath112 , where @xmath113 denotes the cartan matrix and @xmath114 the incidence matrix of the related lie algebra . assuming now that @xmath0 is fixed by the arguments presented above , we obtain for the later case an interesting expression for the statistical interaction @xmath115 in terms of lie algebraic quantities . therefore one may formulate the generalized pauli principle in this context in a lie algebraic form . one of the interesting quantities which may be extracted from the thermodynamic bethe ansatz is the effective central charge of the conformal field theory when taking the ultraviolet limit @xcite , i.e. @xmath116 in ( [ c(r ) ] ) . the integral equation ( [ bftba ] ) simplifies in this case to a set of constant coupled non - linear equations @xmath117 where @xmath118 . in this limit one may approximate @xmath119 in ( [ bftba ] ) and ( [ c(r ) ] ) by @xmath120 @xmath121 . taking thereafter the derivative of ( [ bftba ] ) we obtain , upon the substitution of the result into ( [ c(r ) ] ) , for the effective central charge @xmath122 here @xmath123 @xmath124 = \sum_{n=1}^{\infty } \frac{x^{n}}{n^{2}}+\frac{1}{2}\ln x\ln ( 1-x)$ ] denotes rogers dilogarithm @xcite . in these definitions it is assumed that @xmath125 takes its values between 0 and 1 , which in turn implies that all @xmath126 in ( [ ceff ] ) are to be non - negative . this is in agreement with the physical interpretation of the @xmath126 as ratios of densities . once again with @xmath127 and @xmath128 we recover the well - known expressions for the bosonic and fermionic type of statistical interaction , respectively . obviously the transformation properties discussed in section 4 also survive this limit process . as follows directly from ( [ consttba ] ) they read now @xmath129 apparently this condition is weaker than ( [ trans ] ) . it guarantees equivalence multi - particle systems only at the conformal point . the transformation from bosonic to fermionic statistics is compatible with equations ( 50 ) and ( 51 ) in @xcite for the case b=1 , where such transformations where obtained purely on the conformal level , that is by means of manipulations of certain characters . it is instructive to consider a few examples . for instance having the situation that the difference of the phases of the scattering matrix equals the negative of the statistical interaction , i.e. @xmath130 we always obtain @xmath131 an example for this situation is to consider a system involving the scattering matrix related to ade - affine toda field theory ( recall that in this case @xmath132 @xcite ) and choose the statistical interaction to be fermionic . an interesting structure emerges when considering a system in which the dynamical interaction is described by a direct product of calogero - sutherland scattering matrices , i.e. @xmath133 , and the statistical interaction is taken to be of fermionic type . then ( [ consttba ] ) reduces to @xmath134 the same equation is of course obtained when the statistical interaction is chosen to be bosonic and the coupling constants shifted by one . in some cases ( [ ctba ] ) is solved easily analytically and we can employ ( [ ceff ] ) to compute the effective central charge . we may decompose the effective central charge into contributions coming from different choices for the @xmath135 : @xmath136 . for instance for @xmath137 the solution of ( [ ctba ] ) is @xmath138 and for @xmath139 we obtain @xmath140 . then for @xmath139 and @xmath137 we obtain , with the help of ( [ ceff ] ) , @xmath141 respectively . as already mentioned the computation of the effective central charge by means of ( [ consttba ] ) and ( [ ceff ] ) is not always rigorously justified . however , the explicit analytic computations of the full scaling functions provided in the next section confirm these results . it is intriguing to note that we recover in this way the effective central charges for certain minimal models @xcite . the case @xmath142 corresponds to the minimal model @xmath143 , whilst @xmath144 corresponds to the yang - lee model , i.e. @xmath145 . equation ( [ ctba ] ) may also be solved for different values of @xmath72 and we may compute the effective central charge by means of ( [ ceff ] ) . the dependence of @xmath146 on @xmath72 for the one - particle contribution is depicted in figure 1 . since eq . ( [ ctba ] ) possesses non - negative solutions only at this interval . ] this figure suggests immediately that one may find other minimal models as ultraviolet limits of ( [ c(r ) ] ) for different values of @xmath72 . however , apart from @xmath147 , the two values presented are the only possible choices for a model with solely one particle leading to accessible , with @xmath32 being rational and @xmath148 algebraic @xcite . ] relations for dilogarithms . this implies that other rational @xmath149 do not lead to rational values of @xmath146 . for some class of models it has turned out to be possible to carry out certain manipulations on the tba - equations such that the original integral tba - equations acquire the form of a set of functional equations in new variables @xmath150 ( last ref . in @xcite ) . these functional equations have the further virtue that unlike the original tba - equations they do not involve the mass spectrum and are commonly referred to as @xmath151-systems . in these new variables certain periodicities in the rapidities are exhibited more clearly . these periodicities may then be utilized in order to express the quantity @xmath151 as a fourier series , which in turn is useful to find solution of the tba - equations and expand the scaling function as a power series in the scaling parameter . we will now demonstrate that similar equations may be derived for a multi - particle system in which the dynamical scattering is governed by the scattering matrix related to ade - affine toda field theories and the statistical interaction is of general type . we consider the modified version ( in the sense of ( [ ss ] ) ) of the minimal part of the scattering matrix of ade - affine toda field theories . as was shown in @xcite these s - matrices lead to the identity @xmath152 where @xmath153 denotes the coxeter number , @xmath61 the rank and @xmath114 the incidence matrix of the lie algebra . it is then straightforward to derive the `` @xmath154system '' @xmath155 the quantities @xmath156 and @xmath157 involve now the statistical interaction in the form @xmath158 equations ( [ ysys ] ) follow upon first adding ( [ bftba ] ) at @xmath159 and @xmath160 and subtracting @xmath114 times ( [ bftba ] ) at @xmath19 from the sum . thereafter we employ the fact that the masses of affine toda field theory are proportional to the perron - frobenius vector of the cartan matrix , i.e. @xmath161 @xcite . then , with the help of ( [ rad ] ) and ( [ y ] ) , the equations ( [ ysys ] ) follow . in comparison with ( [ bftba ] ) the equations ( [ ysys ] ) have already the virtue that they are simple functional equations and do not involve the mass spectrum . however , in order to solve them we still have to express @xmath162 in terms of @xmath151 or vice versa , which is not possible in general . however , once the statistical interaction is specified this may be achieved . for instance , for @xmath163 we obtain @xmath164 and recover the known fermionic @xmath151-system . in the bosonic case , i.e. @xmath13 we obtain @xmath165 and for `` semionic '' statistical interaction with @xmath166 we obtain @xmath167 . the most elementary examples which illustrate the features outlined above more concretely is simply to consider the ising model ( @xmath168-minimal affine toda field theory ) @xmath169 or the klein - gordon theory @xmath170 then for both cases equation ( [ bftba ] ) is solved trivially . we obtain @xmath171 for bosonic- and fermionic statistical interaction , respectively . with the help of these solutions we may then compute the entire scaling function . for fermionic statistics we obtain from ( [ c(r ) ] ) @xmath172 whilst bosonic statistics yields @xmath173 where @xmath174 is a modified bessel function . we depict these functions in figure 3(b ) , referring to both of them by a slight abuse of notation as @xmath175 . one observes , that the difference in the statistical interaction is effecting most severely the ultraviolet region . the two scaling functions converge relatively fast towards each other in the infrared regime . we shall encounter these feature also in other models . using the well - known property for the asymptotic behaviour of the modified bessel function @xmath176 leads to @xmath177 for the fermionic and bosonic type equations , respectively . here @xmath179 denotes euler s dilogarithm @xcite . we may also compute some less trivial cases . for instance taking the statistical interaction to be of `` semionic '' type , i.e. @xmath180 we obtain , after solving ( [ bftba ] ) , for the scaling function @xmath181 \cosh \theta \quad \nonumber \\ & = & \frac{12r}{\pi ^{2}}m\sum\limits_{n=0}^{\infty } ( -1)^{n}\frac{(2n-1)!!}{(2n)!!(2n+1)2^{2n+1}}k_{1}((2n+1)rm)\quad . \label{111}\end{aligned}\ ] ] once more we carry out the ultraviolet limit with the help of the asymptotics of the modified bessel function @xmath182 this value of the effective central charge corresponds to the minimal model @xmath143 . this is of course what we expect from section 6 , since with the help of ( [ trans ] ) it can be easily seen that we have thermodynamical equivalence between the calogero - sutherland model with coupling @xmath183 and fermionic statistical interaction and the ising model with `` semionic '' statistical interaction . for @xmath184 we carry out a similar computation and obtain for the scaling function @xmath185 once again we may perform the ultraviolet limit and obtain in this case @xmath186 , which corresponds to the minimal model @xmath145 . this is in agreement with the results in section 6 , since the calogero - sutherland model with coupling @xmath144 and fermionic statistical interaction and the ising model with statistical interaction @xmath184 are thermodynamically equivalent . next we investigate the scaling potts model in this context , which was previously studied by zamolodchikov @xcite with regard to conventional fermionic statistics . the s - matrix of the scaling potts model equals the minimal s - matrix of @xmath187-affine toda field theory @xcite and reads @xmath188 as commented in section 4 , the s - matrix does not satisfy the bootstrap at @xmath189 from our point of view it seems therefore more natural to use its modification in the sense of ( [ ss ] ) and employ bosonic statistics , which of course by the equivalence principle leads to the same tba - equations . the two particles in the model are conjugate to each other , i.e. @xmath190 , and consequently the masses are the same @xmath191 the conjugate particle occurs as a bound state when two particles of the same species scatter , for instance 1 + 1@xmath1922 . for the tba - equation we need @xmath193 then for the fermionic statistics , equation ( [ bftba ] ) can be solved iteratively @xmath194 here we assumed that the @xmath195-symmetry of the model will be preserved such that @xmath196 . once more for @xmath197 we recover the well - known tba - equation of fermionic type ( first ref . in @xcite ) . it appears to be impossible to find analytic solutions to this equation , but it is straightforward to solve it numerically . taking @xmath198 one can iterate this equation as indicated by the superscripts . depending on the value of @xmath199 and @xmath19 , convergence is achieved relatively quickly ( typically n50 ) . the result is shown in figure 2(a ) and appears to be in complete agreement with the calculation in @xcite . to make contact with the literature we introduced the quantity @xmath200 one observes the typical behaviour of @xmath201 for some region of @xmath202 , which is required to derive ( [ consttba ] ) . we now consider a model with fermionic statistical interaction which involves an s - matrix related to the scaling potts model in the sense of ( [ ans ] ) . according to the discussion in sections 4 and 5 , this is equivalent to considering the scaling potts model in which the statistical interaction is taken to be @xmath203 . since @xmath204 ( @xmath205 and @xmath206 denote here the cartan matrix and the incidence matrix of the @xmath187-lie algebra ) , we obtain @xmath207 and the generalized tba - equation ( [ bftba ] ) becomes @xmath208 at first sight @xmath0 in ( [ ndg ] ) seems to be inappropriate since its off - diagonal elements are negative . however , due to the @xmath195-symmetry this does not pose a problem ( c.f . section 2 ) , since @xmath209 and @xmath210 . in fact , this system may be thought of as a bosonic system with one particle species . equation ( [ 53 ] ) may be solved easily numerically in a similar fashion as ( [ a2 ] ) , whereas in comparison with ( [ a2 ] ) convergence is now achieved much faster ( typically @xmath211 ) . the result is shown in figure 2(b ) . having solved the generalized tba - equation for @xmath212 we may also compute the entire scaling function . the result of the numerical computation is depicted in figure 3(b ) for the two types of statistical interactions presented in this subsection . notice that the conformal limit for the exotic statistics corresponds to @xmath213 , which is in agreement with ( [ 37 ] ) . hence in this limit we obtain a one particle bosonic system . due to the fact that the scattering matrices of the scaling potts model and the scaling yang - lee model are related as @xmath214 , the tba - equations for the two models are identical . the only difference occurs due the fact that in the scaling yang - lee model there is only one instead of two particles present and therefore the scaling functions equal each other up to a factor 2 . we finish the discussion of the anyonic scaling potts model with a brief remark on other possible choices of exotic statistics . for example , we may take the s - matrix of the scaling potts model and choose the statistical interaction to be of form @xmath215 . for this choice of @xmath0 the @xmath216-symmetry is also present , so that @xmath210 . this leads , in particular , to a simplification of the system ( [ consttba ] ) . in fact , it reduces to two equations of type ( [ ctba ] ) with @xmath217 and @xmath218 . therefore , the effective central charge describing conformal limit of this anyonic version of the scaling potts model is given by @xmath219 , where @xmath220 is the effective central charge of the calogero - sutherland type model discussed above ( see figure 1 ) . this also means that the conformal limit of the scaling yang - lee model with statistical interaction @xmath221 is described by @xmath222 ( of course , as we discussed in section 6 , this does not imply global equivalence with the calogero - sutherland model ) . finally we present the fermionic computation for the easiest model , which contains at least two different mass values , i.e. @xmath223-affine toda field theory . the minimal s - matrix reads @xcite @xmath224 hence @xmath225 the masses are given by @xmath226 and @xmath227 again we assume that the @xmath195-symmetry is preserved , such that @xmath228 . the tba - equations for fermionic statistics read @xmath229 where @xmath230 for @xmath217 . once again we may solve these equations numerically and compute the entire scaling function . the result is depicted in figure 3(b ) . the functions @xmath231 exhibit the typical plateau as @xmath199 approaches zero . in comparison with the other models we observe that scaling functions for systems with the same statistical interaction have qualitatively the same shape . similarly as in the previous subsection we could now also consider the anyonic system with @xmath232 however , in this case we would have an overall negative contribution of @xmath233 to the density @xmath234 in ( [ dichte ] ) , which as discussed in section 2 seems inappropriate from a physical point of view . we also observed that in the numerical computations singularities occur . however , we may perfectly well choose a different type of statistics which leads to satisfactory equations . for instance , we may choose @xmath215 . in this case equations ( [ consttba ] ) and ( [ ceff ] ) predict that for @xmath235 the conformal limit is described by @xmath146 taking the following values : @xmath236 , @xmath237 , @xmath238 and @xmath239 . one may conjecture that @xmath240 is a monotonically decreasing function . a detailed investigation of whole scaling functions for admittable choices of statistical interaction is left for future studies . for a multi - particle system which involves a factorizable scattering matrix describing the dynamical interaction and a statistical interaction governed by haldane statistics we derived the tba - equations . these equations may be solved by the same means as the conventional tba - equations of fermionic and bosonic type and allow the computation of the entire scaling function . the behaviour of the scaling functions depicted in figure 3(b ) suggests the validity of the conjecture @xcite , that the series for the scaling function in the scaling parameter @xmath61 commences with a constant and thereafter involves quadratic and higher powers in @xmath241 for fermionic type of statistics . for exotic statistics these features do nt seem to be evident . it would be very interesting to generalize these kind of considerations also to the situation in which the dynamical scattering is described by non - diagonal s - matrices ( e.g. affine toda field theory with purely imaginary coupling constant ) , to the excited tba - equations @xcite or even more exotic statistics @xcite . after the completion of our manuscript dr . ilinski pointed out to us , that there exists an ongoing dispute @xcite about how to achieve compatibility between equations ( 1 ) and ( 2 ) , that is to provide a prescription for the counting of the states involving ( 2 ) which would lead to ( 1 ) . there are even doubts whether it is at all possible to achieve compatibility between the two equations . what our manuscript concerns , this is not a crucial issue , since we could also start with a much weaker assumption . we need only ( 1 ) with @xmath242 replaced according to ( 2 ) . we are also grateful to dr . hikami for pointing out reference @xcite to us , in which one also finds a discussion on ideal @xmath221-on gas systems with fractional exclusion statistics . in particular our figure 1 is similar to the figure in there . * acknowledgment : * we would like to thank c. ahn , h. babujian , c. figueira de morisson faria , m. karowski and r. kberle for useful discussions and comments . a.b . is grateful to the volkswagen stiftung and russian fund for fundamental investigations for financial support and to the members of the institut fr theoretische physik for their hospitality . is grateful to the deutsche forschungsgemeinschaft ( sfb288 ) for support .

we derive the thermodynamic bethe ansatz equation for the situation in which the statistical interaction of a multi - particle system is governed by haldane statistics . we formulate a macroscopical equivalence principle for such systems . particular cdd - ambiguities play a distinguished role in compensating the ambiguity in the exclusion statistics . we derive y - systems related to generalized statistics . we discuss several fermionic , bosonic and anyonic versions of affine toda field theories and calogero - sutherland type models in the context of generalized statistics . pacs numbers : 11.10kk , 11.55.ds , 05.70.jk , 64.60.fr , 05.30.-d epsf epsfig.sty -0.7 cm berlin sfb288 preprint + hep - th/9803005 + march 1998

type ia supernovae ( sne ia ) are mature standardised candles . intrinsic dispersion of the peak absolute magnitude can be minimised to the level of @xmath6 magnitude or even smaller , and can be accurately used as a cosmological distance indicator @xcite . however , this standardisation generally requires a non - standard extinction law , i.e. , @xmath7 , as opposed to the typical galactic value of @xmath8 ( e.g. , * ? ? ? this indicates that the properties of dust in sn ia host galaxies may be systematically different from those in our galaxy ( e.g. , * ? ? ? alternatively , it has been suggested that multiple _ scatterings _ of sn photons on circumstellar ( cs ) dust may explain the non - standard nature of the reddening law @xcite . despite the implications that have been discussed ( e.g. , * ? ? ? * ) , researchers have yet to find a smoking gun to test this hypothesis , apart from the various model predictions for optical wavelengths @xcite . this interpretation is also associated with as yet unclarified progenitor evolution , through the dense circumstellar medium ( csm ) and high mass loss rate that would be required . qualitatively , the scenario favours a so - called single - degenerate model ( i.e. , a pair consisting of a c+o white dwarf and a non - degenerate star ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ) , which should create a relatively dense ( or ` dirty ' ) cs environment . in this paper , we examine the effects of _ re - emission _ of sn photons for infrared ( ir ) wavelengths . while the _ ` scattering ' _ must be accompanied by _ ` absorption and re - emission ' _ ( a cs dust echo ) , this process has not been examined with respect to the cs environment around sne ia ( with the exception of recent work that focused on the mid- and far - ir ; * ? ? ? the remainder of this paper is organised as follows . in 2 , we develop a simple echo model for cs dust heated by sn photons . in 3 , we apply the method to observed nir sn ia samples . we place both conservative and deeper limits for the amount of cs dust under different assumptions . in 4 , we discuss the effects of different types of cs dust species , as well as future observational strategies for a better constraint on the amount of cs dust and the environment . the paper is closed in 5 with conclusions . in this section , we present our model of cs dust echoes . we restrict the model to absorption and re - emission processes , not including scattering . this is justified because , ( 1 ) given that the spectral peak of the sn light lies at optical wavelengths , the contribution of the scattered sn light at nir - ir wavelengths is very small , compared to that of thermal emission from cs dust , and ( 2 ) in the distribution of cs dust of interest in this paper , further scattering of the re - emitted nir / ir photons is negligible . while computational methods for an echo from spherically distributed cs dust ( e.g. , * ? ? ? * ; * ? ? ? * ) and further from aspherically distributed cs dust ( especially for modelling the light echo from sn 1987a ; * ? ? ? * ; * ? ? ? * ) have been developed , we assume for the sake of simplicity that the distribution of cs dust is represented by an infinitely thin shell located at radius @xmath9 from the centre of an explosion . the thin - shell approximation further simplifies the computation as shown below . furthermore , in providing an upper limit for the amount of cs dust _ as a function of _ @xmath9 , the thin - shell approximation basically provides the most conservative limit , as any spherically symmetric distribution can be described as a convolution of different shells . namely , if one adds another shell at @xmath10 , that is different from @xmath9 for which the constraint is considered , then this additional shell will increase the predicted flux without contributing to the cs dust mass at @xmath9 ; therefore , the upper limit on this cs dust mass should be reduced ( i.e. , the predicted flux must be below observations ) . let us first consider a situation in which we observe a dust shell with temperature @xmath11 and mass @xmath12 , where @xmath13 is the angle between the observer s line of sight and a direction vector pointing from the shell centre ( i.e. , the explosion centre ) to the position of the volume element within the shell under consideration . then , the luminosity of the thermal emission from dust is given as follows : @xmath14 here , @xmath15 is the absorbing opacity of the dust at frequency @xmath16 . it is specified by the dust properties , which are assumed to be uniform within the shell . furthermore , the shell is assumed to have uniform density ( @xmath17 ) . the above expression can be converted into time - dependent luminosity by introducing @xmath18 ( the time since the explosion , measured in the observer s frame ) and @xmath19 ( observer - frame time when the light was emitted from a given volume element at @xmath13 as observed at time @xmath18 ) . the relationship between @xmath18 and @xmath19 is given by the following : @xmath20 combining eqs . ( 1 ) and ( 2 ) , we obtain the following expression for the echo luminosity at time @xmath18 : @xmath21 the temperature evolution of the cs dust at time @xmath18 , under radiative equilibrium with an incoming sn flux , @xmath22 , is given by @xmath23 this equation provides @xmath24 once the sn flux evolution is specified . under the condition considered in this paper , the photon - dust collision time scale is shorter than the cooling time scale of the dust by thermal radiation . therefore , stochastic heating is negligible , and we can assume that virtually all of the dust particles have a temperature determined by radiative equilibrium . we first compute @xmath24 for a given @xmath9 using the above equation . for the sn flux , we use the hsiao template spectra as an input @xcite . for the dust opacity , we use the lmc - like dust properties as our fiducial model ; specifically , we adopt the opacity from @xmath25 to @xmath26 from @xcite so as to be consistent with the proposed cs scattering model . we extend the opacity toward the blue ( beyond @xmath25 ) and red ( beyond @xmath27 ) , assuming slopes of @xmath28 and @xmath29 , respectively . then the evolution of @xmath24 is used as an input in the computations of echo luminosity and multi - band light curves . because the incoming sn light peaks in optical wavelengths , and because the dust temperature under the situation examined in this paper is determined by the opacity in the nir wavelength , the treatment of the opacity below the @xmath25-band and above the @xmath26-band does not substantially affect our results . to check this , we performed two additional test calculations : one having a slope of @xmath30 below the @xmath25-band and the other having a slope of @xmath31 above the @xmath27-band for our reference lmc dust model ; these models are unrealistically steep and flat , respectively , and thus provide a conservative measure of the uncertainty for the treatment of different slopes . the difference between the reference model and the one using the different slopes ( @xmath32 , @xmath33 , @xmath34 ) is larger for a model with a larger @xmath9 . for the typical maximum distance for which a meaningful constraint is placed at different bands ( see 3 ) , the difference in the echo magnitude is given by @xmath35 mag ( for 0.03 pc ) , @xmath36 mag ( for 0.3 pc ) , and @xmath37 mag ( 1 pc ) for the different slope below the @xmath25-band . for the different slope above the @xmath26-band , @xmath38 mag ( for 0.03 pc ) , @xmath39 mag ( for 0.3 pc ) , and @xmath40 mag ( for 1 pc ) . therefore , in the worst - case scenario , our echo luminosity constraint ( and , thus , the dust mass ) could have an uncertainty factor of 5 ; however , in most cases the uncertainty would be much smaller than this . a further discussion of the dust properties is given in 4.1 . the resulting echo luminosity , as computed above , is for unobscured luminosity . we now consider the optical depth within the shell . the average optical depth is computed as @xmath41 ; then the nir echo luminosity is dimmed by this amount of absorption . the same procedure is adopted for the model with a different geometry ( see below ) . the csm around an sn ia may be confined within the equatorial plane ( e.g. , * ? ? ? * ) , therefore we also consider a torus / ring - like structure , again under the infinitely thin assumption in the radial direction . we denote @xmath42 as the opening angle of the ring , as measured from the equatorial direction . while it is possible to derive general expressions for an arbitrary viewing direction , hereafter , we focus on two extreme cases : pole - on and edge - on viewing . for an observer sitting at the pole - on position , the echo luminosity is expressed as follows : @xmath43 if @xmath44 , then the integral is set to zero . to be an explanation for the non - standard extinction law requires @xmath45 cm , to introduce the effect of scattered photons around the maximum light an observer in the equatorial direction does not have this constraint . we note that both situations should be considered simultaneously , because there should be roughly an equal number of edge - on and pole - on counterparts ( depending on @xmath42 ) , if we adopt the ring - like geometry . finally , the echo luminosity arising from the same configuration , but viewed edge - on , is given as follows . @xmath46 \ .\end{aligned}\ ] ] another interesting possibility for the cs dust distribution is a bipolar morphology , i.e. , a pair of blobs / jets , as inferred for some novae ( e.g. , * ? ? ? therefore , we also consider a pair of bipolar blobs for the distribution of the cs dust , again under the infinitely thin assumption in the radial direction . we denote @xmath42 as the opening angle subtended by each blob , as measured from the polar direction . for an observer sitting at the pole - on position , the echo luminosity is expressed as follows : @xmath47 \ .\end{aligned}\ ] ] the echo luminosity arising from the same configuration , but viewed edge - on , is given as @xmath48 similar to the case of the pole - on observer for the ring - like cs dust distribution , a constraint is placed on the cs dust radius if the multiple scattering model is to account for the non - standard extinction law . for the edge - on observer of the bipolar blob geometry , the cs dust radius must satisfy @xmath45 cm to introduce the scattered photon effect around the maximum light . this constraint does not apply to the pole - on observer ; however , both situations ( pole - on and edge - on ) should be considered simultaneously , following the same argument given for the ring - like geometry . figure 1 shows the evolution of @xmath49 and the predicted nir ( @xmath50 , @xmath51 , @xmath26 ) light curves for different values of @xmath9 and for a fixed value of @xmath12 ( @xmath52 ) ; for the light curves , only the shell model is shown . the evolution of @xmath49 closely follows the optical light curve of sn ia . for @xmath53 pc , the peak temperature exceeds @xmath54k ; therefore , the dust may well have evaporated , depending on the nature of the cs dust . in such a case , essentially there should be neither scattering nor thermal emission from the cs dust . therefore , no constraint can be obtained regarding the amount of pre - existing cs dust , _ and _ the cs dust can not be an origin of the non - standard extinction law toward sne ia . the effects of different geometries are demonstrated in fig . 2 ; light curves are shown for the shell csm , pole - on and edge - on views for a ring - like csm with @xmath55 , and pole - on and edge - on views for bipolar blobs with @xmath56 . throughout this paper , we consider these geometry types for the cs dust distribution , while adopting the shell model as our fiducial model . the light curve evolution is similar in various nir bands ; its time scale is basically determined by the travelling time of light , and thus the cs dust at larger @xmath9 results in a longer - lived , fainter nir echo . for small @xmath9 , the travelling time of light is shorter than the time scale of the sn light curve evolution ; thus in this case , the light curve reflects the sn light curve evolution , and the echo light curve evolution traces the decreasing temperature of the cs dust as a function of time . on the other hand , for large @xmath9 , the travelling time of light far exceeds the sn light curve evolution time scale ; therefore , the temperature evolution has little influence on the shape of the light curve . emission at longer wavelengths is stronger for larger @xmath9 , which stems from smaller @xmath49 for larger @xmath9 . as such , the peak wavelength in the thermal emission is shorter than the @xmath50-band for smaller @xmath9 , while it is even longer than the @xmath26-band pass for larger @xmath9 . figure 3 shows examples of the constraint on the amount of cs dust using the shell model . without the dust echo , nir luminosities of sne are powered by radioactive decay of @xmath57co and subsequent thermalisation ; the nir spectral energy distribution ( sed ) roughly follows a blackbody of @xmath58 k in the early photospheric phase ( @xmath59 days ) , while the sed reflects the forbidden lines of fe - peak elements in late nebular phases ( @xmath60 days ) . in any case , a conservative upper limit on the cs dust mass is obtained by the condition that the resulting echo luminosity can not exceed the observation at any epochs . as the echo luminosity is proportional to @xmath12 in the optically thin regime , for a given @xmath9 , one can derive a maximally allowed value for @xmath12 . note that this is not a fit to the observed light curve the echo light curve model for small @xmath9 resembles the observed light curve to some extent , but this is because the echo evolution follows the sn evolution for small @xmath9 ( see above ) . the left panel of fig . 3 shows how an early - phase light curve ( up to @xmath61 days since the @xmath62-band maximum ) can be used to constrain the amount of cs dust . generally , the early phase data provide a strong constraint on @xmath12 for small @xmath9 , but lose diagnostic power for cs dust at large @xmath9 . the model prediction for small @xmath9 is similar for different bands ; typically the @xmath50-band provides the deepest limit , thanks to its extensive coverage within the nir . we note that the @xmath63-band , which typically has much better coverage than the @xmath50-band , is not so useful for this purpose , as the wavelength of the thermal emission peak is longer than that of the @xmath63-band . the right panel of fig . 3 shows the other extreme within the nir wavelengths , namely a constraint obtained through late - time photometry in the @xmath26-band . such an observation can provide a constraint on the cs dust at large @xmath9 , up to @xmath64 pc . by applying different models ( i.e. , with a different @xmath9 and geometry ) to the available , observed , multi - band light curves , a constraint can be obtained for @xmath12 as a function of @xmath9 for each sn the light curves for different bands provide mutually independent upper limits ; we adopted the strongest limit among @xmath50 , @xmath51 , and @xmath26 . the result is shown in fig . 4 , where the method was applied to a ` typical nir observation ' using the csp sample , sn 2006x , as an example of very intensively observed early - phase light curves , including the @xmath26-band and extending to a relatively late epoch ; also shown are sne 1998bu , 2000cx , 2001el , 2003du , and 2003hv , for which nir late - phase ( @xmath64 year ) magnitudes are available . it is seen that generally the strongest constraints are obtained through the @xmath50 or @xmath51-band data for the cs dust at @xmath65 pc , and through the @xmath26-band at @xmath66 pc . figure 4 also contains lines indicating various physical situations . the thick solid lines indicate the absorptive optical depth in the @xmath62-band , which gives indication of the likelihood that the cs dust is the origin of the non - standard extinction law ( i.e. , an optical depth of an order unity is required ) . the thin solid lines show the equivalent mass loss rates of the progenitor systems ; we adopted the dust - to - gas ratio of 0.01 ( i.e. , @xmath67 , where @xmath68 is the velocity of the mass loss outflow ) . vertical dashed lines show the temperature of the cs dust as a function of @xmath9 . figure 4 shows that the upper limits for @xmath12 , as obtained in the argument using the nir echo ( with the shell model ) , are @xmath69 for the cs dust at @xmath70 pc , @xmath71 at @xmath72 pc , and @xmath73 at @xmath74 pc . beyond this radius , the results are especially sensitive to the quality of the observational data , as essentially one needs still - rare late - time photometry for the @xmath26-band . the strongest constraints for @xmath66 pc are obtained for sne 2000cx , 2001el , and 2003hv , which are only three examples to date having the late time @xmath26-band photometry at @xmath64 year . for these sne , @xmath75 is derived for @xmath76 pc . at @xmath77 pc , even the nir bands are too blue ; thus , we can only provide a very loose constraint on the cs dust mass as @xmath78 , even for the best - case scenario ( sn 2003hv ) . to probe the cs dust beyond @xmath79 pc , mid- or far - ir observations should be more effective @xcite . the derived upper limits are sufficiently tight to constrain the origin of the non - standard extinction as a scattered echo , as proposed by @xcite and @xcite . the resulting upper limit for the optical depth in the @xmath62-band is generally @xmath80 for the cs dust at @xmath65 pc . at @xmath66 pc , the constraint is weaker , but for a few sne , we place the constraint as @xmath81 at @xmath76 pc . above @xmath79 pc , the upper limit is consistent with @xmath82 . these values should be compared to the requirement that the optical depth must be at an order of unity for the scattered echo to have a substantial effect on the extinction law . from this analysis , we conclude that it is difficult for the scattered echo to be a general origin of the non - standard extinction law toward sne , as long as the cs dust is placed at @xmath65 pc . a possibility that the cs dust at @xmath77 pc creates the non - standard extinction law is not rejected , although categorising it as ` cs ' dust is questionable ( see below ) . a dust shell at @xmath83 pc is rejected for some sne ia when the late - time @xmath26-band data are available , but not generally constrained due to a lack of such data . the above constraints are for the shell model . one might guess that the constraint would be weakened if the cs dust is confined in a specific direction , e.g. , in an equatorial ring or in bipolar blobs , as the cs dust mass required to create @xmath82 should be reduced . while this is true , several additional effects must be considered . first , the shell model does indeed provide the most conservative upper limit on the cs dust mass . if one confines the same amount of cs dust in a specific direction , then the local density increases . this generally results in larger luminosity at a specific epoch than in the corresponding shell model , and thus a tighter limit on @xmath12 is obtained using the observational data at the corresponding epoch ( fig . 2 ) . for example , the edge - on ring model predicts a larger luminosity than the shell model with the same cs dust mass at the beginning and the end of the nir echo . in contrast , the same model viewed pole - on has a shorter duration and a larger luminosity . this large luminosity in the ring model is achieved when the emission at the ring - edge reaches the observer . a similar argument applies to the blob model . as for the required cs dust mass within the scattering echo model for the extinction law , it is true that the required mass is reduced for an edge - on observer to the ring - like cs dust structure ( fig . 4 ) . however , for the pole - on case , this effect is compensated for by an increase in the predicted luminosity ( fig . thus , the resulting upper limit for @xmath84 in the pole - on ring model is similar to that of the shell model ( fig . 4 ) . statistically , there must be edge - on and pole - on counterparts ; the nir echo constraint in this paper , using a number of sne , is sufficiently strong to reject this possibility . if one introduces a _ more confined _ configuration , then this increases the likelihood that it will not be viewed from that direction . in addition , for a pole - on observer to have a substantial scattering effect , the time required for light to travel to the cs dust must be shorter than the rising time of sne ia ( i.e. , @xmath85 days ) , and therefore the cs dust beyond @xmath86 pc never affects the extinction law if viewed pole - on . the above argument should be slightly modified for a very confined case , such as when considering the bipolar blob geometry . similar to the ring - like geometry , the upper limits on the cs dust mass for a bipolar blob are comparable to or deeper than the corresponding shell model , depending on the viewing direction . if this is converted into the optical depth , the derived upper limits are indeed not extremely strong to readily reject the multiple scattering model for the extinction law , i.e. , @xmath82 ( fig . however , in this case , the amount of scattered photons should already be limited , due to a small opening angle subtended by the distribution of cs dust . in summary , introducing the confined cs geometry does not help interpret the non - standard extinction law as _ generally _ having come from cs scattered light . sne suffering a substantial ` cs ' scattering echo effect must be limited to at most only a fraction of sn ia samples . for the cs dust to have originated from the mass loss of a progenitor , the cs gas mass should be @xmath87 a few @xmath88 , i.e. , @xmath89 a few @xmath90 . this amount of cs dust can create a substantial scattering effect , only if @xmath91 pc , even if we use the conservative requirement @xmath92 ( or @xmath93 pc if we adopt @xmath82 ) . we generally reject such a large amount of cs dust at @xmath91 pc ( see above ) . therefore , if the echo scenario is to be a general origin of the non - standard extinction law , then the dust must indeed be ism in origin , located at @xmath94 pc . one may question what implications this mass loss rate may have for the progenitor scenario . indeed , the cs scattering model requires a much larger amount of csm , compared to that predicted by typical progenitor scenarios . our limit is @xmath95 yr@xmath1 for the mass - loss wind velocity of @xmath2 km s@xmath1 below 0.01 pc , or , in the final @xmath96 years before the explosion . this is not as strong as the constraint from radio and x - rays ( e.g. , @xmath97 yr@xmath1 for the same velocity , for sn 2011fe : * ? ? ? * ; * ? ? ? however , we emphasise that radio and x - rays probe the materials inside @xmath98 pc ; our proposed method using the nir echo can extend the constraint by an order of magnitude in the spatial dimension ( or to the past before the explosion ) , making our limit independent and unique . from the present analysis ( see below for possible improvement ) , the only scenario that can be marginally rejected , for _ normal _ sne examined in this paper , is a symbiotic system . however , we do note that sne ia resulting from this path may appear as an atypical sn ia @xcite . thus far , our limit has been rather conservative , and is based on the condition that the echo luminosity can not exceed the observed one . however , most of the light should have originated from a radioactive decay chain and subsequent thermalisation , as demonstrated by nir spectroscopy @xcite . given this observational fact , we can refine our limit as follows . first , attribute the _ template _ light curves in each band to the sn light without any contribution of the possible nir echo ; subtract the templates from the light curves from individual sne ; and then use the residual light curve ( here we take the absolute value if the subtraction results in a negative value ) to place an upper limit on the cs dust mass . namely , we assume that the echo luminosity does not exceed the _ variation _ in the nir light curves , seen in different sne . as a demonstration , in fig . 3 ( left panel ) we show the case of sn 2006x , for which a good light curve is available . the figure shows that the magnitude of this residual light curve is @xmath99 less than that of the original , highlighting the standard nature of the nir light curves . using this argument , much tighter constraints can be obtained ( as shown by the thin solid lines in fig . 3 ) . figure 5 shows the results for sn 2006x . because @xmath50- and @xmath51-band data are of the best quality , following the template closely , the upper limit for the cs dust mass , especially at @xmath65 pc , improved significantly . for small @xmath9 , the upper limit was reduced by two orders of magnitude , which reflects a residual light curve that was fainter than the original by @xmath100 magnitudes . with this method , all of the models with different geometric types result in @xmath101 ( @xmath102 for most situations ) , robustly rejecting the cs scattering model for the extinction law for this particular sn . the upper limit for the mass loss rate is now @xmath103 yr@xmath1 for @xmath70 pc , much deeper than the conservative limit , as described earlier in this section . in this paper , our analysis has been based on a particular dust model , i.e. , the lmc - type dust opacity . in this section , we examine the effects of different types of cs dust . figure 6 shows the ` conservative ' limits on the cs dust mass derived for ( a ) astronomical silicate and ( b ) amorphous carbon or graphite , both for the shell model . figure 7 shows the same but for the ` deeper limit ' for sn 2006x ( i.e. , figure 5 but for astronomical silicate or carbon ) . the opacities are calculated using optical constants by @xcite and @xcite . to the first approximation , the behaviour can be understood by the difference in a typical opacity for different dust models , e.g. , the opacity in the @xmath62-band . the opacity is roughly a factor of two lower for silicate than the reference lmc - like dust model ; thus , the upper limit for the cs dust mass is weakened by the same factor . the opacity is roughly an order of magnitude higher for carbon than the lmc - like dust model , and therefore the upper limit on the cs dust mass is deeper for the carbon dust model by an order of magnitude than our fiducial model . however , these different constraints on the cs dust mass would not substantially alter the constraints on the ability of the cs dust to create the non - standard extinction law . the optical depth itself is scaled by the same factor ; therefore , the upper limits on @xmath84 would not change substantially . our results should be compared to sne , in which a large amount of dust is inferred either by the detection of an optical ( scattered ) echo or other probes ( e.g. , narrow absorption systems ) . for example , we have obtained a tight limit for the amount of cs dust for sn 2006x ( fig . 5 ) , while this sn was detected in a scattered echo @xcite ; its optical spectrum at @xmath64 year after the explosion showed a blue echo component , indicating @xmath82 . in contrast , we obtained the constraint that @xmath104 , as long as the echo source is at @xmath105pc ( or even @xmath102 at @xmath65 pc ) . taken together , the detected echo in sn 2006x must be created by ism , as suggested by @xcite using hubble space telescope ( _ hst _ ) data . to date , even for cases where an ( optical ) echo is detected , evidence of a cs echo remains weak . another example is highly extinct sn ia 2014j in m82 . no variability has been found in the narrow absorption lines ( e.g. , * ? ? ? @xcite have claimed temporal evolution in @xmath106 , while no apparent variability has been detected in polarisation measurements @xcite . while a consistent interpretation for all of these features has yet to be reached , it seems that together they suggest that the cs scattering scenario is unlikely , but perhaps a combination of multiple scattering and true absorption at the ism scale could provide a consistent solution . indeed , detection of an echo has been reported for sn 2014j through high - resolution _ hst _ images at @xmath107 days after the explosion @xcite . this has been interpreted as echoes originating at the interstellar scale . at this epoch , the sn still dominates the light in the vicinity of the sn and no strong signature of the echo from the cs dust has been obtained ( see also * ? ? ? * ) . in fig . 8 , we show the results of simulated @xmath26-band images of an echo from the cs dust located at @xmath108 pc for different geometries , for an sn at @xmath109 mpc . for the ring and blob geometries , we have adopted @xmath110 and the viewing direction of @xmath111 for the purpose of demonstration . the model images are convolved with a gaussian kernel of @xmath112 arcsec to roughly simulate observations by _ hst _ ; the narrow field channel of _ hst / nicmos _ has a spatial resolution of @xmath113 arcsec at @xmath114 . thus our simulation could overestimate the spatial resolution up to @xmath115% , but it could anyway be compensated by increasing the assumed physical scale of the cs dust by the same factor . note that these images are for a ` pure ' echo component if the projected echo size is smaller than or comparable to the instrument s spatial resolution , then the sn must fade away below the level of the echo luminosity to examine the geometry of the echo signal . note that there is a better chance to apply this exercise to later epochs . figure 8 shows the expected evolution covering @xmath100 years , to investigate the possibility of distinguishing different cs dust geometries if a cs dust echo is detected . even for nearby sn 2014j and using _ hst _ , probing the cs dust echo using spatially resolved imagery can be difficult . for a ring - like structure , an elongated structure is visible when @xmath116 . for this particular bipolar blob model , the echo ` disappears ' when @xmath116 . for both models , there is a ( non - monotonic ) shift in the centre of the echo light . the size of this shift for these particular models is about half of the spatial resolution , and could be detectable with precision astrometry techniques . these diagnostics could apply to sn 2014j if the cs dust echo is detected in the future following the sn luminosity decrease . continuous _ hst _ high - resolution observations are strongly encouraged . while investigation of the cs echo through direct imaging observations is currently limited by the spatial resolution of @xmath5 arcsec at nir wavelengths even with _ hst _ ( 4.2 ) , the situation is expected to improve dramatically in the coming decade . the planned james webb space telescope ( _ jwst _ ) will reach to a spatial resolution by a factor of @xmath117 better than _ hst_. furthermore , with the availability of nir adaptive optics ( ao ) attached to @xmath118 m class telescopes such as the thirty meter telescope ( tmt ) , european extremely large telescope ( e - elt ) , and giant magellan telescope ( gmt ) , spatial resolutions of @xmath3 arcsec are expected . figures 9 and 10 show synthesised images at different epochs for an sn at a distance of @xmath109 mpc , surrounded by cs dust shell / ring / blobs , as viewed with a spatial resolution of @xmath119 arcsec ( for the viewing direction of @xmath111 as a specific example ) . with this resolution , one can distinguish different cs dust geometries , even for the cs dust located at @xmath120 pc . for a spherically symmetric distribution , investigation of the radial distribution is within reach , as seen by the hole for the shell model . the ring and blob models show asymmetric image profiles that are clearly different from the shell model ( but depend on the viewing direction ) . the shift of the centre in these models should be easily resolved beyond the spatial resolution for example , using this shift , the blob model is distinguishable from any spherically symmetric distribution . an sn at a distance of @xmath109 mpc is a rare event , at an observed rate of one per decade or two . figures 11 and 12 show the same images , but for an sn at a distance of @xmath121 mpc . at this distance , we expect an event rate of roughly one per year ; thus , such observations are , in principle , annual occurrences . for cs dust located at @xmath120 pc around an sn at a distance of @xmath121 mpc , as observed by _ tmt / e - elt / gmt _ ( fig . 11 ) , the situation is similar to the case shown in fig . an elongated profile of the ring distribution could be marginally resolved , and the shift in images for asymmetrically distributed cs dust ( e.g. , ring or blobs ) could be detectable by a sub - spatial resolution astrometry . for the cs dust at @xmath108 pc , observations with a spatial resolution of @xmath119 arcsec can distinguish various cs dust geometries , given that such echo signals are detected . thus , we conclude that the proposed future high - resolution nir ao can open up a new window to examine the cs environment around nearby sne . we note that a target does not have to be one discovered after the new instruments become available . for example , sn 2014j can already be a target assuming an observation at year 2024 , cs dust located at @xmath122 pc can still be investigated . pilot work on this measurement may already be possible with @xmath123 m class telescopes approaching the diffraction limit ( @xmath93 arcsec ) . we investigated the effects of _ re - emission _ of sn photons by cs dust for ir wavelengths . we have shown that this effect allows observed ir light curves to be used to place constraints on the position / size and the amount of cs dust . we applied the method to observed nir sn ia samples , and found that meaningful upper limits on the cs dust mass can be derived , even under conservative assumptions . our results are summarised as follows : 1 . @xmath69 for the cs dust at @xmath70 pc , @xmath71 at @xmath72 pc , and @xmath73 at @xmath74 pc . the mass loss rate must be generally @xmath95 yr@xmath1 up to @xmath124 pc , rejecting a symbiotic path as a main population of the _ normal _ sne ia . 3 . for a particular case of sn 2006x , a deeper limit is obtained ( see below ) : @xmath125 for the cs dust at @xmath70 pc , @xmath69 at @xmath72 pc , and @xmath126 at @xmath74 pc . the corresponding mass loss rate ( upper limit ) is @xmath127 yr@xmath1 up to @xmath128 pc and @xmath103 yr@xmath1 up to @xmath129 pc . the above upper limits become tighter if one considers a non - spherical cs distribution . the above upper limits become even tighter by an order of magnitude for carbon dust . from these results , we conclude the following regarding the possibility of the dust - scattering scenario for the non - standard extinction law toward sne ia : 1 . the ` cs ' dust ( at @xmath130 pc ) echo can not be a general explanation of the non - standard extinction law with regard to sne ia . the scenario would work for at most a fraction of sne ia , presumably at most , the highly reddened ones . if the echo scenario is responsible for the extinction law in general , then the dust must be located at @xmath77 pc . the required mass is , however , @xmath131 ; therefore , this must be attributed to ism rather than csm . we have also demonstrated an approach that allows deeper limits to be applied . this involves first using the standard nature of the nir light curves . we demonstrated this for sn 2006x , showing that the upper limit can be deepened by two orders of magnitude from the conservative limit , as given above . we suggest that further improvement is possible by refining the analysis method along this line via standardisation of the nir light curves for a given sample and minimisation of the dispersion as a function of time . this would allow a deeper limit to be placed on the mass loss rate , potentially to the level to limit various models other than the particular symbiotic scenario . again , one of the main advantages of the proposed method , compared to radio and x - ray constraints ( which are indeed complementary to the proposed method here ) , is the following : the limit to the amount of dust placed by the nir echo extends an order of magnitude larger in the spatial dimension ( or an order of magnitude to the past in the time dimension ) , reflecting the fact that the light speed ( for the echo ) is by an order of magnitude faster than the shock velocity ( for radio and x - rays ) . as we have shown in this paper , late - time photometry , even sparse , especially in the @xmath26-band , is essential to constrain dust ( and gas ) mass in the environment at @xmath66 pc . our method underlines the importance and usefulness of such data . our analysis is also highlighted by the possibilities of ( 1 ) constraining the origin of the non - standard extinction law , and ( 2 ) constraining the csm mass up to @xmath64 pc , namely the regimes that the other methods like radio and x - ray diagnostics can not probe . because the data are still rare , we propose increasing the sample of nir / mid - ir sne with continuous observational efforts . of course , if one wants to go further toward the ism regime , mid- and far - ir data are important @xcite , and a combination of the early radio / x , early and late - time nir , and late - time mid-/far - ir , perhaps complemented by the absorption system study ( e.g. , * ? ? ? * ) , will hopefully provide a complete view of these issues . we also investigated the possibility of studying the cs dust distribution through high spatial resolution observations . our results are summarised below . 1 . cs dust around sn 2014j could potentially be resolved by future _ hst _ observations , given that dense cs dust shell / ring / blobs exist at @xmath77 pc from the sn site . future nir ao instruments attached to @xmath118 m class telescopes are capable of distinguishing various distributions of cs dust , thus providing a powerful means for investigating the cs environment around sne ia . 3 . such observations will be possible for nearby sne at a rate of roughly once a year . the authors thank ariel goobar for fruitful discussion . k.m . acknowledges financial support by grant - in - aid for scientific research ( no . 23740141 and 26800100 ) from the japanese ministry of education , culture , sports , science and technology ( mext ) . the work by k.m . is partly supported by world premier international research center initiative ( wpi initiative ) , mext , japan . the authors also thank the anonymous referee for her / his many constructive comments .

the circumstellar ( cs ) environment is key to understanding progenitors of type ia supernovae ( sne ia ) , as well as the origin of a peculiar extinction property toward sne ia for cosmological application . it has been suggested that multiple _ scatterings _ of sn photons by cs dust may explain the non - standard reddening law . in this paper , we examine the effect of _ re - emission _ of sn photons by cs dust in the infrared ( ir ) wavelength regime . this effect allows the observed ir light curves to be used as a constraint on the position / size and the amount of cs dust . the method was applied to observed near - infrared ( nir ) sn ia samples ; meaningful upper limits on the cs dust mass were derived even under conservative assumptions . we thereby clarify a difficulty associated with the cs dust scattering model as a general explanation for the peculiar reddening law , while it may still apply to a sub - sample of highly reddened sne ia . for sne ia in general , the environment at the interstellar scale appears to be responsible for the non - standard extinction law . furthermore , deeper limits can be obtained using the standard nature of sn ia nir light curves . in this application , an upper limit of @xmath0 yr@xmath1 ( for the wind velocity of @xmath2 km s@xmath1 ) is obtained for a mass loss rate from a progenitor up to @xmath3 pc , and @xmath4 yr@xmath1 up to @xmath5 pc . [ firstpage ] circumstellar matter stars : mass - loss dust , extinction supernovae : general .

modern quantum field theories are based on fundamental symmetries . this holds for quantum electrodynamics ( qed ) as well as for the standard model of elementary particle physics . whenever physicists talk about symmetries they usually think of gauge invariance or the discrete symmetries charge conjugation _ c _ , parity _ p _ , and time reversal _ t_. however , there is one symmetry that often takes a back seat : lorentz invariance . this is not surprising , since until now there had been no convincing experimental evidence for a violation of lorentz invariance . however , a violation of other symmetries is part of the everyday life of any high - energy physicist . for example , violations of _ p _ and _ cp _ were measured long ago @xcite and a broken electroweak gauge symmetry with massive @xmath0 , and @xmath1 bosons is an experimental fact . why then should lorentz symmetry and its violation not be of interest ? there exist good theoretical arguments for lorentz invariance being a symmetry that is restored at low energies @xcite . at the planck length the topology of spacetime may be dynamical , which could lead to it having a foamy structure . the existence of such a spacetime foam @xcite may define a preferred reference frame as is the case for water in a glass and thus violate lorentz invariance . since a fundamental quantum theory of spacetime is still not known , we have to rely on well - established theories such as the standard model or special relativity for a description of lorentz violation . by introducing new parameters that deform these theories it is possible to parameterize lorentz violation on the basis of standard physics . one approach is to modify dispersion relations of particles . however , such a procedure is very _ ad hoc _ and it is not evident where the modification comes from . therefore , a more elementary possibility is to parameterize modifications on the level of lagrange densities . a collection of all lorentz - violating deformations of the standard model that are gauge invariant is known as the lorentz - violating extension of the standard model @xcite . the minimal version of this extension relies on power - counting renormalizable terms , whereas the nonminimal version also includes operators of mass dimension @xmath2 ( see e.g. the analyses performed in @xcite ) . the theoretical consistency of the standard model itself has been verified by investigations based on lorentz - invariant quantum field theory that were performed over decades ( see , for example , ref . @xcite ) . however , it is not entirely clear if a lorentz - violating theory is consistent . some results on certain sectors of the standard model extension already exist @xcite , but there still remains a lot what we can learn about lorentz - violating quantum field theories . because of this it is very important to check lorentz - violating deformations with respect to fundamental properties such as microcausality and unitarity . furthermore , it is of significance whether the modified theory approaches the standard theory for arbitrarily small deformations . the purpose of this paper is to investigate these questions . especially in the case where lorentz violation resides in the photon sector , it can lead to a variety of new effects , for example a birefringent vacuum @xcite , new particle decays @xcite , and `` aetherlike '' deviations from special relativity , which are modulated with the rotation of the earth around the sun ( e.g. refs . @xcite ) . from an experimental point of view , photons produce clean signals making the photon sector very important , in bounding lorentz - violating parameters . there exist two gauge - invariant and power - counting renormalizable deformations of the photon sector : maxwell chern simons theory ( mcs - theory ) @xcite and modified maxwell theory @xcite . each lagrangian contains additional terms besides the maxwell term of standard electrodynamics . the consistency of the isotropic and one anisotropic sector of modified maxwell theory was already shown in @xcite . in this article a special sector , that violates parity and is supposed to show no birefringence , will be investigated . the paper is organized as follows . in sec . 2 modified maxwell theory is presented and restricted to the parity - odd nonbirefringent case . additionally , it is coupled to a standard dirac theory of massive spin-1/2 fermions , which leads to a theory of modified qed . in secs . 3 and 4 , we review the nonstandard photon dispersion relations and the gauge propagator , which are determined from the field equations @xcite . that completes the current status of research concerning this special sector of modified maxwell theory . the successive parts of the article deal with the main issue , beginning with the deformed polarization vectors , which can also be obtained from the field equations . after setting up the building blocks we are ready to discuss unitarity in sec . 6 and microcausality in sec . the subsequent two sections are devoted to the polarization vectors themselves . since their form is rather uncommon even when considering lorentz - violating theories we make comparisons with mcs - theory and other sectors of modified maxwell theory . it will become evident that the polarization vectors have a property that distinguishes them from the polarization vectors of standard electrodynamics , even in the limit of vanishing lorentz violation . to test , whether or not some residue of the deformation remains in this limit , in sec . 9 we compute the cross section of the simplest tree - level process involving external modified photons that is also allowed by standard qed : compton scattering . we conclude in the last section . readers may skip secs . 4 8 on first reading . in this article , we focus on modified maxwell theory @xcite . this particular lorentz - violating theory is characterized by the action [ eq : action - modified - maxwell - theory ] @xmath3 \mathcal{l}_\text{modmax}(x)&= & -\frac{1}{4}\ , \eta^{\mu\rho}\,\eta^{\nu\sigma}\,f_{\mu\nu}(x)f_{\rho\sigma}(x ) -\frac{1}{4}\ , \kappa^{\mu\nu\varrho\sigma}\,f_{\mu\nu}(x)f_{\varrho\sigma}(x)\ , , \label{eq : l - modified - maxwell - theory}\end{aligned}\ ] ] which involves the field strength tensor @xmath4 of the @xmath5 gauge field @xmath6 . the fields are defined on minkowski spacetime with global cartesian coordinates @xmath7 @xmath8 @xmath9 @xmath8 @xmath10 and metric @xmath11 @xmath8 @xmath12 @xmath13 @xmath14 . the first term in eq . represents the standard maxwell term and the second corresponds to a modification of the standard theory of photons . the fixed background field @xmath15 selects preferred directions in spacetime and , therefore , breaks lorentz invariance . the second term in eq . is expected to have the same symmetries as the first . these correspond to the symmetries of the riemann curvature tensor , which reduces the number of independent parameters to 20 . furthermore , a vanishing double trace , @xmath16 , is imposed . a nonvanishing @xmath17 can be absorbed by a field redefinition @xcite and does not contribute to physical observables . this additional condition leads to a remaining number of 19 independent parameters . modified maxwell theory has two distinct parameter sectors that can be distinguished from each other by the property of birefringence . the first consists of 10 parameters and leads to birefringent photon modes at leading - order lorentz violation . the second is made up of 9 parameters and shows no birefringence , at least to first order with respect to the parameters . since the 10 birefringent parameters are bounded by experiment at the @xmath18 level @xcite , we will restrict our considerations to the nonbirefringent sector , which can be parameterized by the following _ ansatz _ @xcite : @xmath19 with a constant symmetric and traceless @xmath20 matrix @xmath21 . here and in the following , natural units are used with @xmath22 , where @xmath23 corresponds to the maximal attainable velocity of the standard dirac particles , whose action will be defined in sec . [ sec : coupling - to - standard - dirac - particles ] . there exists a premetric formulation of classical electrodynamics , that is solely based on the concept of a manifold and does not need a metric . in this context a tensor density @xmath24 ( electromagnetic field strength ) and pseudotensor densities @xmath25 , @xmath26 ( electromagnetic excitation and electric current ) are introduced . since the resulting field equations for these quantities are underdetermined , an additional relation between @xmath24 and @xmath25 has to be imposed , which is governed by the so - called constitutive four - tensor @xmath27 . modified maxwell theory emerges as one special case of this description , namely as the principal part of the constitutive tensor previously mentioned @xcite . in eq ( d.1.80 ) of the book @xcite the nonbirefringent _ ansatz _ of eq . can be found , as well . section d.1.6 gives a motivation for it as the simplest but not the most general decomposition of the principal part of @xmath27 . furthermore , note that a special sector of _ cpt_-even modified maxwell theory arises as a contribution of the one - loop effective action of a _ cpt_-odd deformation involving a spinor field and the photon field @xcite . the anisotropic case considered concerns the parity - odd sector of modified maxwell theory with the _ ansatz _ from eq . . this case is characterized by one purely timelike normalized four - vector @xmath28 and one purely spacelike four - vector @xmath29 containing three real parameters @xmath30 , @xmath31 , and @xmath32 : [ eq : definition - parity - odd - case ] @xmath33 ( \xi^{\mu})&=&(1,\,0,\,0,\,0)\,,\quad ( \zeta^{\mu } ) \equiv ( 0,\,2\,\boldsymbol{\zeta } ) = ( 0,\,2\,\widetilde{\kappa}^{01},\ , 2\,\widetilde{\kappa}^{02},\ , 2\,\widetilde{\kappa}^{03})\ , , \label{eq : definition - parity - odd - case - four - vectors } \\[2 mm ] ( \widetilde{\kappa}^{\mu\nu})&=&\begin{pmatrix } 0 & \widetilde{\kappa}^{01 } & \widetilde{\kappa}^{02 } & \widetilde{\kappa}^{03 } \\ \widetilde{\kappa}^{01 } & 0 & 0 & 0 \\ \widetilde{\kappa}^{02 } & 0 & 0 & 0 \\ \widetilde{\kappa}^{03 } & 0 & 0 & 0 \\ \end{pmatrix}\,,\end{aligned}\ ] ] where is the most general _ ansatz _ for a symmetric and traceless tensor constructed from two four - vectors . the second term on the right - hand side of vanishes for the special choice . with the replacement rules given in @xcite , we can express our parameters in terms of the standard model extension ( sme ) parameters @xcite : [ eq : parity - odd - case - sme ] @xmath34 hence , the case considered here includes only parity - violating coefficients . this parity - odd case may be of relevance , since it might reflect the parity - odd low - energy effective photon sector of a quantum theory of spacetime . besides five parameters of the birefringent sector of modified maxwell theory , whose coefficients are already strongly bounded , there is only one alternative parity - odd lorentz - violating theory for the photon sector , which is gauge - invariant and power - counting renormalizable : mcs theory @xcite . however , the mcs parameters are bounded to lie below @xmath35 by cmb polarization measurements @xcite . since the bounds are not as strong for the parity - odd case of nonbirefringent modified maxwell theory defined by eq . , a physical understanding of this case is of importance . modified photons are coupled to matter by the minimal coupling procedure to standard ( lorentz - invariant ) spin-@xmath36 dirac particles with electric charge @xmath37 and mass @xmath38 . this results in a parity - odd deformation of qed @xcite , which is given by the action @xmath39 = s_\text{modmax}^\text{parity - odd}\big[\widetilde{\kappa}^{0m}\big ] + s^\text{}_\text{dirac}\big[e , m\big ] \,,\ ] ] for @xmath40 , 2 , 3 and with the modified - maxwell term for the gauge field @xmath41 and the standard dirac term for the spinor field @xmath42 , @xmath43 = \int_{\mathbb{r}^4 } \mathrm{d}^4 x \ ; \overline\psi(x ) \big [ \gamma^\mu \big(\mathrm{i}\,\partial_\mu -e a_\mu(x ) \big ) -m\big ] \psi(x)\,.\ ] ] equation is to be understood with standard dirac matrices @xmath44 corresponding to the minkowski metric @xmath45 . the field equations @xcite of modified maxwell theory in momentum space , @xmath46 lead to the following dispersion relations @xcite for the two physical degrees of freedom of electromagnetic waves ( labeled @xmath47 ) : [ eq : dispersion - relation - p - odd-1 - 2 ] @xmath48 \omega_2(\mathbf{k})&= & \widetilde{\kappa}^{01}k_1\ , + \widetilde{\kappa}^{02}k_2\ , + \widetilde{\kappa}^{03}k_3\ , + \sqrt{1+(\widetilde{\kappa}^{01})^2 + ( \widetilde{\kappa}^{02})^2+(\widetilde{\kappa}^{03})^2}\;|\mathbf{k}| \label{eq : dispersion - relation - p - odd-2}\,,\end{aligned}\ ] ] for wave vector @xmath49 and with the terms linear in the components @xmath50 explicitly showing the parity violation . to first order in @xmath51 , the dispersion relations are equal for both modes , but they differ at higher order .. nevertheless we will still use the term `` nonbirefringent '' in order to distinguish from the nine - dimensional parameter sector of modified maxwell theory , which shows no birefringence at least to first - order lorentz violation , from the remaining ten coefficients . in the latter parameter region birefringent modes emerge already at first order with respect to the lorentz - violating parameters @xcite . ] with the modified coulomb and ampre law it can be shown that the dispersion relations indeed belong to physical photon modes . the procedure given in @xcite eliminates dispersion relations of unphysical , i.e. scalar and longitudinal , modes from the field equations . the two are given by @xmath52 where the index `` 0 '' refers to the scalar and the index `` 3 '' to the longitudinal degree of freedom of the photon field . the dispersion relations can be cast in a more compact form by defining components of the wave - vector @xmath53 which are parallel or orthogonal to the background `` three - vector '' @xmath54 : @xmath55 where @xmath56 and @xmath57 . by doing so , it is possible to write the dispersion relations as follows : [ eq : dispersion - relation - p - odd-1 - 2-mathcale ] @xmath58 @xmath59 where the three lorentz - violating parameters @xmath30 , @xmath31 , and @xmath32 are contained in the single parameter @xmath60 that is defined as @xmath61 it is obvious that @xmath62 , whereas each single parameter @xmath30 , @xmath31 , and @xmath32 can be either positive or negative . from the first definition of eq . we see that negative parameters @xmath30 , @xmath31 , @xmath32 are mimicked by a negative @xmath63 . the phase and group velocity @xcite of the above two modes can be cast in the following form for small enough @xmath60 : [ eq : phase - velocity ] @xmath64 @xmath65 [ eq : group - velocity ] @xmath66 @xmath67 where @xmath68 is the angle between the three - momentum @xmath53 and the unit vector @xmath69 : @xmath70 . to leading order in @xmath60 , the velocities above are equal : @xmath71 furthermore , eqs . , show that both phase and group velocity can be larger than 1 . however , what matters physically is the velocity of signal propagation , which corresponds to the front velocity @xcite : @xmath72 equation can be interpreted as the velocity of the highest - frequency forerunners of a signal . as can be seen from eq . , @xmath73 and hence also @xmath74 do not depend on the magnitude of the wave vector , but only on its direction . for @xmath75 , we obtain @xmath76 , where [ eq : inequalities - front - velocity ] @xmath77 observe that , for small enough @xmath60 , having @xmath78 or @xmath79 does not depend on the lorentz - violating parameters but only on the direction in which the classical wave propagates . for completeness , we also give the phase velocities for propagation parallel and orthogonal to @xmath69 : @xmath80 @xmath81 with the sign function @xmath82 note that the latter results are in agreement with the inequalities of eq . . we conclude that the front velocity can be larger than 1 for the wave vector pointing in certain directions . that leads us to the issue of microcausality , which will be discussed in sec . [ sec : microcausality - parity - odd ] . so far , we have investigated the dispersion relations of the classical theory . for a further analysis , especially concerning the quantum theory , the gauge propagator will be needed . the propagator is the green s function of the free field equations in momentum space . in order to compute it the gauge has to be fixed . we decide to use the feynman gauge @xcite , which can be implemented by the gauge - fixing condition @xmath83 the following _ ansatz _ for the propagator turns out to be useful : @xmath84 the propagator coefficients @xmath85 , @xmath86 , @xmath87 and the scalar propagator part @xmath88 follow from the system of equations @xmath89 with the differential operator @xmath90 in feynman gauge transformed to momentum space . scalar products @xmath91 , @xmath92 , and @xmath93 will be kept in the result , in order to gain some insight in the covariant structure of the functions . however , we remark that , for the case considered , @xmath94 , @xmath95 , and @xmath96 . specifically , the propagator coefficients and the scalar propagators @xmath97 and @xmath98 , where @xmath98 appears in some of these coefficients , are given by [ eq : propagator - result - parity - odd - scalar-1 - 2 ] @xmath99 [ eq : propagator - result - parity - odd - coeff ] @xmath100 @xmath101 @xmath102\,\widehat{k}_2\ , , \label{eq : propagator - result - parity - odd - coeff - d}\ ] ] @xmath103 @xmath104\,\widehat{k}_2\,,\ ] ] @xmath105 @xmath106+k^2\big[12\,k\cdot\xi\,k\cdot\zeta+\xi^2(k\cdot\zeta)^2 \nonumber \\ & & \quad\,+\zeta^2(k\cdot\xi)^2+k^2(4-\xi^2\zeta^2)\big]\,,\end{aligned}\ ] ] @xmath107\,\widehat{k}_2\,,\ ] ] where definition enters . the poles of @xmath97 and @xmath98 can be identified with the dispersion relations obtained in sec . [ sec : dispersion - relations - classical - causality ] . from @xmath108 , that is @xmath109 the dispersion relation of the @xmath110 mode is recovered . similarly , the dispersion relation of the @xmath111 mode follows from @xmath112 , that is @xmath113 the third pole @xmath114 corresponds to the dispersion relation of scalar and longitudinal modes . this is clear from the fact that this pole appears only in the gauge - dependent coefficients @xmath115 , @xmath116 , and @xmath117 . these are multiplied by at least one photon four - momentum and vanish by the ward identity , ] if they couple to a conserved current @xcite . since the ward identity results from gauge invariance , it also holds for modified maxwell theory , which is expected to be free of anomalies @xcite . because of parity violation the physical poles are asymmetric with respect to the imaginary @xmath118-axis . the above result equals the propagator given in @xcite . every propagator coefficient , which contains the scalar propagator @xmath98 , is also multiplied by @xmath97 . hence , both modes appear together throughout the propagator and the question arises , whether they can be separated . it can be shown that the propagator can also be written in the following form : @xmath119 where the tensor structure @xmath120 is the same for both parts , hence @xmath121 with the coefficients @xmath122 , , @xmath123 from eq . . the scalar propagator functions are then given by : @xmath124\zeta^2+(k\cdot\zeta)^2}\ , , \quad \widehat{g}^{(2)}(k)=-\frac{4}{[(k\cdot\xi)^2-k^2]\zeta^2+(k\cdot\zeta)^2}\ , . \label{eq : split - propagator - scalar - parts}\ ] ] the first part @xmath125 contains both polarization modes encoded in @xmath97 and @xmath98 , whereas the second part does not involve any mode . the denominator @xmath126\zeta^2+(k\cdot\zeta)^2 $ ] that appears in both parts does not have a zero with respect to @xmath127 , hence it contains no dispersion relation . so it does not seem that the polarization modes can be separated , such that each propagator part contains exactly one of the modes . finally , we can state that the structure of the propagator of parity - odd nonbirefringent modified maxwell theory is rather unusual . in the next section we will compute the polarization vectors . in what follows , the physical ( transverse ) degrees of freedom will be labeled with ( 1 ) and ( 2 ) , respectively . for a fixed nonzero `` three - vector '' @xmath54 and a generic wave vector @xmath53 , the polarization vector of the @xmath110 mode reads @xmath128 where @xmath129 is a normalization factor to be given later . the polarization vector of the @xmath111 mode is orthogonal to and has a longitudinal component . it is given by @xmath130 with [ eq : polarization - mode2-parity - violating - explict ] @xmath131\big)\,,\ ] ] @xmath132 the polarization vector @xmath133 is a solution of the field equations , when @xmath118 is replaced by @xmath134 from eq . . the polarization @xmath135 is the corresponding solution for @xmath118 replaced by @xmath136 from eq . . the normalization factors @xmath129 in and @xmath137 in can be computed from the 00component of the energy - momentum tensor . note that the above polarization vectors have been calculated in the lorentz gauge , @xmath138 . for the lorentz - violating decay processes considered , both the @xmath110 and the @xmath111 polarization modes contribute . @xmath139 with [ eq : polarization - sum - coefficients-1 ] @xmath140}{q(\zeta\cdot k)}\,,\quad\widehat{\lambda}_1=-\frac{k\cdot\zeta}{q}\,,\ ] ] @xmath141 @xmath142-(k\cdot\zeta)^2\,,\ ] ] where @xmath143 is given by . the denominator @xmath144 vanishes only for @xmath145 or @xmath146 . if the polarization tensor of the @xmath110 mode is contracted with a gauge - invariant expression using the ward identity , , which we denote by the word `` truncated '' ] it can be replaced by @xmath147 : @xmath148 @xmath149 the polarization tensor of the @xmath111 mode is lengthy and is best written up in terms of @xmath150 and @xmath151 defined in . @xmath152 with [ eq : polarization - sum - coefficients-2 ] @xmath153 ^ 2\,,\end{aligned}\ ] ] @xmath154\omega_2 ^ 2\big\}\,,\end{aligned}\ ] ] @xmath155\,,\end{aligned}\ ] ] @xmath156 ^ 2\,,\end{aligned}\ ] ] @xmath157 @xmath158\,,\end{aligned}\ ] ] @xmath159\,.\end{aligned}\ ] ] where @xmath160 and @xmath161 is given by . again , if the tensor is contracted with a gauge - invariant expression , it can be replaced by @xmath162 : @xmath163 @xmath164 finally it holds that @xmath165 where the second contraction only vanishes for @xmath166 due to the longitudinal part of @xmath167 . the polarization vector is normalized to unit length by @xmath168 . this normalization factor cancels in @xmath162 . note that the metric tensor @xmath45 does not appear on the right - hand side of , whereas it does on the right - hand side of eq . . furthermore , note that each truncated polarization tensor @xmath147 and @xmath162 can be written in a covariant form . this behavior is different from the polarization vectors of standard qed , where only the whole polarization sum is covariant . it is now evident that not only is the structure of the photon propagator uncommon , but the polarization vectors are unusual as well . in the next section we will analyze how both results are connected . in order to investigate unitarity , the simple test of reflection positivity used in ref . @xcite for the isotropic case of modified maxwell theory can not be adopted , because there are now essentially two different scalar propagators , namely @xmath97 and @xmath98 from . hence , we could either examine reflection positivity of the full propagator or study the optical theorem for physical processes involving modified photons . as unitarity of the s matrix results in the optical theorem and the latter is directly related to physical observables , we choose to proceed with the second approach . the optical theorem will also show how the modified photon propagator in sec . [ sec : propagator - parity - odd ] is linked to the photon polarizations from the previous section . the following computations will deal with the physical process that we already considered for isotropic modified maxwell theory @xcite in the context of unitarity : annihilation of a left - handed electron @xmath169 and a right - handed positron @xmath170 to a modified photon @xmath171 . the fermions are considered to be massless particles , which renders their helicity a physically well - defined state . neglecting the axial anomaly , which is of higher order with respect to the electromagnetic coupling constant , the axial vector current @xmath172 is conserved : @xmath173 . this is the simplest tree - level process including a modified photon propagator . it has no threshold and is allowed for both photon modes . we assume a nonzero lorentz - violating parameter @xmath60 . furthermore , the four - momenta of the initial electron and positron are not expected to be collinear . if the optical theorem holds , the imaginary part of the forward scattering amplitude @xmath174 is related to the cross section for the production of a modified photon from a left - handed electron and a right - handed positron : @xmath175 herein , @xmath176 is the corresponding one - particle phase space element . by performing an integration over the four - momentum of the virtual photon , the forward scattering amplitude @xmath177 is given by @xmath178\\ & \phantom{{}={}\int \frac{\mathrm{d}^4k}{(2\pi)^4}}\,\times\frac{1}{\widehat{k}_1^{-1}+\mathrm{i}\epsilon}\ ; \big(+\eta_{\nu\lambda } + \widehat{b}\,k_{\nu}k_{\lambda } + \widehat{c}\,\xi_{\nu}\xi_{\lambda } + \widehat{d}\,(k_{\nu}\xi_{\lambda}+\xi_{\nu}k_{\lambda } ) \notag \\ & \phantom{{}={}\int \frac{\mathrm{d}^4k}{(2\pi)^4}\,\times\frac{1}{\widehat{k}_1^{-1}+\mathrm{i}\epsilon}\;\big(}+\widehat{e}\,\zeta_{\nu}\zeta_{\lambda } + \widehat{f}\,(k_{\nu}\zeta_{\lambda}+\zeta_{\nu}k_{\lambda } ) + \widehat{g}\,(\xi_{\nu}\zeta_{\lambda}+\zeta_{\nu}\xi_{\lambda})\big)\,,\end{aligned}\ ] ] with the propagator coefficients @xmath115 , , @xmath123 from eq . . recall , that the physical poles have to be treated via feynman s @xmath179-prescription . hence , the denominator @xmath180 from eq . , which appears in the coefficients @xmath115 , @xmath181 , @xmath116 , @xmath182 , @xmath117 , and @xmath123 also has to be replaced by @xmath183 . the first contribution to the imaginary part of the matrix element @xmath184 comes from the physical pole of the scalar propagator function @xmath97 and corresponds to the dispersion relation of the @xmath110 polarization mode . using the positive and negative photon frequency of the parity - odd case considered , @xmath185 the scalar part of the propagator is @xmath186 the pole with positive real part can be cast in the following form : @xmath187 because of energy conservation only @xmath188 and not @xmath189 contributes to the imaginary part . we define @xmath190 and obtain : @xmath191\\ & = \int \frac{\mathrm{d}^3k}{(2\pi)^{3}\,2\widetilde{\omega}_1^+}\,\delta^{(4)}(k_1+k_2-k)\ , ( \widehat{\mathcal{m}}_{\widehat{1}}^{\,\dagger})^{\nu}(\widehat{\mathcal{m}}_{\widehat{1}})^{\mu}\big(\pi_{\mu\nu}|_{\lambda=1}\big ) \notag \displaybreak[0]\\[1 mm ] & = \int \frac{\mathrm{d}^3k}{(2\pi)^{3}\,2\widetilde{\omega}_1^+}\,\delta^{(4)}(k_1+k_2-k)\left . with @xmath192 and @xmath118 replaced by the dispersion relation @xmath193 from eq . . furthermore , @xmath194 using the ward identity , in the first step of eq . we could eliminate all propagator coefficients that are multiplied by at least one photon four - momentum . then we employed the truncated @xmath110 polarization tensor from eq . . the second contribution to the imaginary part of the matrix element comes from the @xmath111 mode given by the dispersion relation . that mode is contained in @xmath98 from , where feynman s @xmath179-prescription leads to : @xmath195 with @xmath196 the pole with the positive real part results in the following contribution to the imaginary part of the matrix element @xmath197 : @xmath198 again , the pole @xmath199 with negative real part does not contribute because of energy conservation . using the ward identity leads to : @xmath200\xi^{\mu}\xi^{\nu}+\big[(k\cdot \xi)^2-k^2\xi^2\big]\zeta^{\mu}\zeta^{\nu}\big . \notag \\ & \hspace{3.20cm}\,\big.+\big[2\,k^2+k\cdot\xi\,k\cdot\zeta\big](\xi^{\mu}\zeta^{\nu}+\zeta^{\mu}\xi^{\nu})\big\ } \notag \\ & = \int \frac{\mathrm{d}^3k}{(2\pi)^{3}\,2\widetilde{\omega}_2^+}\,\delta^{(4)}(k_1+k_2-k)\ , ( \widehat{\mathcal{m}}_{\widehat{1}}^{\,\dagger})^{\nu}(\widehat{\mathcal{m}}_{\widehat{1}})^{\mu}\big(\pi_{\mu\nu}|_{\lambda=2}\big ) \notag \\ & = \int \frac{\mathrm{d}^3k}{(2\pi)^{3}\,2\widetilde{\omega}_2^+}\,\delta^{(4)}(k_1+k_2-k)\left . where @xmath201 and @xmath118 is to be replaced by @xmath202 from eq . moreover , we have used that for @xmath203 @xmath204\xi^{\mu}\xi^{\nu } + \big[(k\cdot \xi)^2-k^2\xi^2\big]\zeta^{\mu}\zeta^{\nu}\big . \notag \\ & \big.+\big[2\,k^2+k\cdot\xi\,k\cdot\zeta\big](\xi^{\mu}\zeta^{\nu } + \zeta^{\mu}\xi^{\nu})\big\}=\pi^{\mu\nu}|_{\lambda=2}\,,\end{aligned}\ ] ] with the right - hand side given by . adding the two contributions from eqs . and leads to @xmath205 but the right - hand side of the previous equation is just the total cross section of the scattering process . hence , the optical theorem is valid for the parity - odd sector of modified maxwell theory . furthermore , it reveals the connection between the modified photon propagator ( cf . eq . ) and the polarization tensors ( cf . penultimate line of eqs . and ) . the optical theorem thus provides a good cross check for the obtained results of eqs . since the process itself only plays a role at the level of providing a valid ward identity , the obtained result is consistent with having a unitary theory , at least for a tree - level process involving conserved currents . as a final remark we state that the unphysical pole @xmath114 , which appears in the propagator coefficients @xmath115 , @xmath116 , and @xmath117 , is prevented from being reached by energy conservation . hence it plays no role in the calculation . in order to decide whether or not the particular case of parity - odd modified maxwell theory considered satisfies the condition of microcausality , we have to compute the commutator of physical fields at different spacetime points @xmath206 and @xmath207 . the latter can be derived from the commutator of vector potentials : @xmath208=[a^{\mu}(y - z),a^{\nu}(0)]\equiv [ a^{\mu}(x),a^{\nu}(0)]=\mathrm{i}\theta^{\mu\nu}\widehat{d}(x)\,,\ ] ] where the second step follows from translation invariance . the tensor structure of this expression is to be put into the function @xmath209 . the causal structure of the commutator is completely determined by the scalar commutator function @xmath210 , which corresponds to the scalar part of the feynman propagator ( see , for instance , refs . @xcite and @xcite ) . for this reason we will restrict our considerations solely to @xmath210 and forget about the tensor structure . looking at the propagator of sec . [ sec : propagator - parity - odd ] it is clear that there are two scalar parts , @xmath97 from eq . and @xmath98 from eq . , one for each photon polarization . we begin with @xmath97 : @xmath211 & = \oint_{c } \frac{\mathrm{d}k_0}{2\pi } \int \frac{\mathrm{d}^3k}{(2\pi)^3}\ ; \frac{1}{k_0 ^ 2-k_{\bot}^2-k_{\parallel}^2 - 2\,\mathcal{e}\,k_0\,k_{\parallel } } \;\exp(\mathrm{i}\,k_0x_0+\mathrm{i}\,\mathbf{k}\cdot\mathbf{x } ) \notag \\[1 mm ] & = \oint_{c } \frac{\mathrm{d}k_0}{2\pi } \int \frac{\mathrm{d}^3k}{(2\pi)^3}\ ; \frac{1}{(k_0-\widetilde{\omega}_{1}^+)(k_0-\widetilde{\omega}_{1}^{- } ) } \;\exp(\mathrm{i}\,k_0x_0+\mathrm{i}\,\mathbf{k}\cdot\mathbf{x})\,,\end{aligned}\ ] ] where positive and negative energies are defined in eq . . these are the poles of the scalar propagator @xmath97 , where @xmath212 delivers the first contribution to the imaginary part of the forward scattering amplitude considered in the previous section . the evaluation of the contour integral gives @xmath213 \exp(\mathrm{i}\,\mathbf{k}\cdot\mathbf{x } ) \notag \\[1 mm ] & = -\int \frac{\mathrm{d}^3k}{(2\pi)^3}\ , \frac{1}{\sqrt{k_{\bot}^2+(1+\mathcal{e}^2)\,k_{\parallel}^2 } } \;\sin\left(\sqrt{k_{\bot}^2+(1+\mathcal{e}^2)\,k_{\parallel}^2}x_0\right ) \notag \\ & \hspace{3cm}\,\times \exp\big(\mathrm{i}\,k_{\bot}x_{\bot } + \mathrm{i}\,(\mathcal{e}x_0+x_{\parallel})k_{\parallel}\big)\,.\end{aligned}\ ] ] substituting @xmath214 the integral results in @xmath215 with @xmath216 hence , eq . is of the same form as an integral that appears in the context of the standard propagator ( see e.g. eq . ( 26a ) in ref . this leads to the final result : @xmath217 & = -\frac{1}{2\pi\sqrt{1+\mathcal{e}^2}}\ ; \mathrm{sgn}(x_0)\ ; \delta\big((x_0-\mathcal{e}\,x_{\parallel})^2 -(1+\mathcal{e}^2)\,x_{\bot}^2-(1+\mathcal{e}^2)\,x_{\parallel}^2\big)\,.\end{aligned}\ ] ] just as for the isotropic case of modified maxwell theory , whose consistency was discussed in ref . @xcite , the commutator function vanishes everywhere except on the modified null cone @xmath218 an analogous calculation for the scalar part @xmath98 from eq . delivers the following final result for the commutator function @xmath219 : @xmath220 which corresponds to a second modified null cone : @xmath221 both null cones coincide to linear order in @xmath60 . this is not surprising , since the theory is birefringent to quadratic order in the lorentz - violating parameters . each of the eqs . and corresponds to a null cone , whose rotation axis is different for the past and future null cone . neither axes coincides with the time axis , but each is rotated by a small angle , as shown in fig . [ fig : modified - null - cones ] . . their rotation axes are shown as well ( thin lines ) . ] since there are two modes with two different dispersion relations , one may wonder , if this result is sufficient for taking a decision about microcausality . for this reason we tried to separate both modes in sec . [ sec : propagator - parity - odd ] with the result . therefore , we should investigate @xmath222 and @xmath223 from eq . : @xmath224\zeta^2+(k\cdot\zeta)^2}\exp(\mathrm{i}\,k_0x_0+\mathrm{i}\,\mathbf{k}\cdot\mathbf{x } ) \notag \\ & = \oint_c \frac{\mathrm{d}k_0}{2\pi } \int \frac{\mathrm{d}^3k}{(2\pi)^3}\,\frac{4\widehat{k}_2^{-1}}{[(k\cdot\xi)^2-k^2]\zeta^2+(k\cdot\zeta)^2}\frac{\exp(\mathrm{i}\,k_0x_0+\mathrm{i}\,\mathbf{k}\cdot\mathbf{x})}{(k_0-\widetilde{\omega}_1^+)(k_0-\widetilde{\omega}_1 ^ -)}\,.\end{aligned}\ ] ] using @xmath225\zeta^2+(k\cdot\zeta)^2}\right|_{k_0=\widetilde{\omega}_1^+}=\left.\frac{4\widehat{k}_2^{-1}}{[(k\cdot\xi)^2-k^2]\zeta^2+(k\cdot\zeta)^2}\right|_{k_0=\widetilde{\omega}_1 ^ -}=1\,,\ ] ] then leads to the intermediate result of eq . and the rest of the computation is the same . since @xmath223 is a constant function with respect to @xmath127 , the evaluation of the contour integral in the complex @xmath127-plane in @xmath226 will immediately give zero . hence , the dispersion relation corresponding to the second mode does not seem to play any role here . the @xmath110 mode seems to be preferred compared to the @xmath111 mode , what follows from forcing a parity - odd theory to be nonbirefringent via the _ ansatz _ . the transversal polarization vectors can be interpreted as two distinct polarization modes : left- and right - handed . in a parity - violating theory they are expected to behave differently , for example with respect to their phase velocity . this would automatically lead to birefringence , which is suppressed by using eq . as a basis . the result of eq . establishes microcausality for the following parameter domain : @xmath227 where @xmath54 is defined in terms of the sme parameters by eqs . and . hence , the parity - odd `` nonbirefringent '' sector of modified maxwell theory is unitary and microcausal for the full parameter range . in the previous sections we have seen that both the modified photon propagator and the polarization vectors have an uncommon structure . for this reason , we want to have a general look at the photon propagator and polarization vectors in other lorentz - violating theories . we start with the photon polarizations of mcs theory . besides modified maxwell theory , mcs theory is another possible example of a gauge - invariant and power - counting renormalizable theory that violates lorentz invariance in the photon sector . mcs theory is characterized by a mass scale @xmath228 and a fixed spacelike to be spacelike , since timelike mcs theory is expected to be nonunitary and noncausal @xcite . ] `` four - vector '' @xmath29 , that plays the role of a background field . the chern simons mass @xmath228 gives the amount of lorentz violation . mcs theory exhibits two photon modes , which we call ` @xmath229 ' and ` @xmath230 ' . they obey different dispersion relations @xcite , which results in birefringence . the polarization vectors follow from the field equations and , in temporal gauge @xmath231 , they are given by @xmath232\,,\,\mathrm{i}\frac{2\omega}{m_{\mathrm{\scriptscriptstyle{cs}}}}k^2\,,\,2k_{\parallel}k_{\bot}\right)\bigg|_{\omega=\omega_{\oplus}}\,,\ ] ] @xmath233\,,\,\mathrm{i}\frac{2\omega}{m_{\mathrm{\scriptscriptstyle{cs}}}}k^2\,,\,2k_{\parallel}k_{\bot}\right)\bigg|_{\omega=\omega_{\ominus}}\,,\ ] ] with the normalization constants @xmath234\big|_{\omega=\omega_{\oplus}}\,,\quad n''=4\frac{\omega^2k^2}{m^2_{\mathrm{\scriptscriptstyle{cs}}}}[2k^2+m^2_{\mathrm{\scriptscriptstyle{cs}}}\zeta^2]\big|_{\omega=\omega_{\ominus}}\,.\ ] ] using the temporal gauge fixing four - vector @xmath235 , the polarization tensor for each of the two modes can be cast in the following form ( see @xcite for the truncated versions ) : [ eq : polarization - tensors - mcs - theory ] @xmath236 @xmath237 where @xmath238\,.\end{aligned}\ ] ] the polarization sum of standard qed is expected to be recovered for vanishing @xmath228 . for the truncated polarization sum this is , indeed , the case : @xmath239 from @xmath240 it is evident that both modes deliver equal contributions to the polarization sum . this even holds for nonvanishing @xmath228 . hence , the behavior of mcs theory with respect to the polarization modes is completely different compared to parity - odd nonbirefringent modified maxwell theory . for @xmath241 , there is no residual dependence from the preferred spacetime direction @xmath29 in the polarization tensors of the individual modes , which can be seen from eq . . furthermore , for mcs - theory the photon propagator in the axial gauge has been shown to be of the following form @xcite : @xmath242 where further terms with the index structure composed of the four - momentum , the preferred spacelike four - vector @xmath29 , the axial gauge vector and the four - dimensional levi - civita symbol have been omitted . the denominator @xmath243 is a fourth - order polynomial in @xmath118 , with its zeros corresponding to the two different physical dispersion relations . for a special case of parity - odd ` birefringent ' modified maxwell theory , @xmath244 ( corresponding to the first two entries of the ten - dimensional vector from eq . ( 8) in @xcite ) plus those related by symmetries and all others set to zero ] we could show that the propagator in feynman gauge looks like @xmath245 where @xmath246 is a second - order polynomial in @xmath118 , involving the lorentz - violating parameters and @xmath247 is of fourth order in @xmath118 . the two distinct physical dispersion relations of this birefringent theory follow from @xmath248 . again , remaining propagator coefficients multiplied by combinations of the four - momentum and preferred four - vectors have been omitted . hence , we see that our result for the propagator for parity - odd nonbirefringent modified maxwell theory given by eqs . is rather unusual . for mcs - theory and birefringent modified maxwell theory ( at least for the special case examined ) , both physical modes emerge as poles of the coefficient before the metric tensor @xmath12 . however , in the case of parity - odd nonbirefringent modified maxwell theory , the dispersion relation for the @xmath111 polarization mode is not contained in the coefficient @xmath97 of eq . , which is multiplied with @xmath12 . this peculiarity is also mirrored in the polarization tensors , where we have shown the interplay in the previous section . taking the limit @xmath166 followed by the limit @xmath249 ( see the definition ) for the physical polarization vectors and leads to : @xmath250 taking into account the limit of the four - momentum , @xmath251 the physical polarization vectors reduce to the standard transversal qed results . note that for both vectors in eq . , the order in which the limits are taken does not play any role . as we will see below , this is not the case for the gauge - invariant parts of the polarization tensors from eqs . , , that is , if the polarization vectors are coupled to conserved currents . for @xmath166 these tensors result in : [ eq : polarization - tensors - physical - limit ] @xmath252 @xmath253 with @xmath254 and @xmath255 . for completeness , after inserting the explicit four - vectors , we obtain the following matrices : @xmath256 @xmath257 note that these matrix representations only hold for the special choice @xmath258 . it is evident that the additional limit @xmath249 does not exist for each contribution @xmath147 or @xmath162 separately , but only for the truncated polarization sum @xmath259 , which leads to the standard qed result . for this reason , the polarization vectors are not only deformed unlike for the isotropic case that was examined in ref . @xcite but their structure completely differs from standard qed . besides that , no covariant expression exists for each polarization tensor in standard qed , where only the sum @xmath259 can be decomposed covariantly . the results obtained for the polarization vectors in sec . [ sec : polarization - vectors - parity - odd ] together with the observations that followed forces us to think about the consistency of the modified theory . the form of the propagator , the polarization vectors and tensors observed in secs . [ sec : propagator - parity - odd ] , [ sec : polarization - vectors - parity - odd ] , and [ sec : limit - polarizations - vanishing - lorentz - violation ] reveal the following uncommon properties : * one of the two physical photon modes seems to be preferred with respect to the other , * both polarization vectors are interweaved with the spacetime directions @xmath28 and @xmath29 , even for vanishing lorentz - violating parameters , * each physical polarization tensor can be written in covariant form , * and one of the physical polarization vectors has a longitudinal part . one the one hand , these peculiarities may emerge from the fact that a parity - odd qed is combined with the claim of being nonbirefringent . two physical photon polarizations can be interpreted as two distinct polarization modes:``left - handed '' and `` right - handed '' . these are supposed to behave differently because of parity violation , for example with respect to the phase velocity of each mode . hence , birefringence would result from this , which clashes with the nonbirefringent _ ansatz _ of eq . . on the other hand , the above properties may have emerged from a bad gauge choice and could possibly be removed by picking a more appropriate gauge . for this reason a physical process will be considered , whose cross section does not depend on the gauge . if the mentioned behavior of the polarization modes is not a gauge artifact , it will show up in the results for polarized cross sections . the simplest tree - level process involving external photons , which also occurs in standard qed , is compton scattering . we consider an electron scattered off a photon in the @xmath110 polarization and in the @xmath111 polarization , respectively . hence , we want to compute cross sections for the processes @xmath260 , @xmath261 , @xmath262 , and @xmath263 , where @xmath264 denotes a modified photon in the @xmath110 or @xmath111 polarization state , respectively . the corresponding feynman diagrams are shown in fig . [ fig : compton - scattering ] . , where the subscript refers to the photon polarization . the photon momenta are denoted as @xmath265 and the electron momenta as @xmath266 , where the label @xmath267 , 2 refers to the initial and final state , respectively . ] for a review of compton scattering experiments , refer to ref . furthermore , ref . @xcite gives a new bound on two of the three parameters of parity - odd nonbirefringent modified maxwell theory from the study of compton scattering kinematics at the graal experiment on the european synchrotron radiation facility ( esrf ) at grenoble in france . we choose special momenta @xmath268 , @xmath269 for the initial electron and photon . the outgoing photon momentum configuration is described in spherical coordinates with polar angle @xmath270 and azimuthal angle @xmath271 . we consider the initial momentum configuration , for which the electron is at rest : @xmath272 , @xmath273 with @xmath274 . [ 1]>m#1 c0.85cm||c2.1cm|c2.1cm|c2.1cm|c2.1cm|c2.1cmc0.1 cm & & & & & + & & & & & + & & & & & + & & & & & + [ 1]>m#1 c0.95cm||c1.6cm|c1.6cm|c1.6cm|c1.6cm|c1.6cm|c1.6cm|c2.0cmc0.1 cm & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + [ 1]>m#1 c1.0cm||c1.6cm|c1.6cm|c1.6cm|c1.6cm|c1.6cm|c1.6cm|c1.6cmc0.1 cm & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + [ 1]>m#1 c0.95cm||c1.6cm|c1.6cm|c1.6cm|c1.6cm|c1.6cm|c1.6cm|c1.6cmc0.1 cm & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + & & & & & & & + [ 1]>m#1 c0.6cm|c0.6cm|c0.6cm||c1.5cm|c1.5cm|c1.5cm|c1.5cm|c1.5cm|c1.5cm|c1.5cmc0.1 cm & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + & & & & & & & & & + values for the modified polarized compton scattering cross sections @xmath275 , @xmath276 , @xmath277 , and @xmath278 are obtained . these correspond to the processes @xmath279 , @xmath280 , @xmath281 , and @xmath282 , where the numbers give the initial and final photon polarization , respectively . to form gauge - invariant expressions , the sum over final photon polarizations has to be performed : [ eq : modified - compton - cross - sections - gauge - invariant - sums ] @xmath283 @xmath284 our calculation is based on the assumption that only the initial photon state can be prepared , especially its polarization . however , the final photon polarization can only be measured , if the photon is observed or scattered at a second electron . since we consider the final photon as an asymptotic particle according to the feynman diagrams in fig . [ fig : compton - scattering ] , it is not observed and one has to sum over final photon polarizations @xcite . hence , what can be measured in this context are only the quantities @xmath285 and @xmath286 , so we also give them . finally , we list the sum of all cross sections , which is averaged over the initial photon polarizations : @xmath287 for comparison with the modified compton cross sections , the cross sections for unpolarized and polarized compton scattering in standard qed are presented in table [ tab : compton - scattering - standard - qed-1 ] and table [ tab : compton - scattering - standard - qed-2 ] , respectively , for different initial photon momenta @xmath269 . an important issue has to be mentioned first : the calculation of the modified cross section in the parity - odd theory can be performed in two different ways . the first possibility is to calculate the matrix element squared _ la _ sec . ( 11.1 ) of ref . @xcite by directly using the modified polarization vectors from eqs . , . for completeness , we give this equation in a compact form : @xmath288(\cancel{p}_1+m)\right . \notag \\ & \phantom{{}={}\frac{1}{4}\mathrm{tr}}\hspace{-0.125cm}\left.\times\left[\frac{1}{\upsilon_1 } \cancel{\varepsilon}^{(\lambda)}(\cancel{p}_1+\cancel{k}_1+m)\cancel{\varepsilon}^{(\lambda')}-\frac{1}{\upsilon_2}\cancel{\varepsilon}^{(\lambda')}(\cancel{p}_1 -\cancel{k}_2+m)\cancel{\varepsilon}^{(\lambda)}\right](\cancel{p}_2+m)\right\}\,,\end{aligned}\ ] ] where @xmath289 here , @xmath290 denotes the initial and @xmath291 the final photon polarization . for standard qed eq . results in eq . ( 11 - 13 ) of ref . @xcite ( which we transform to fit our conventions ) : @xmath292 ^ 2\,,\end{aligned}\ ] ] @xmath293 alternatively , the computation can be performed with the matrix element squared that is obtained without the direct use of the polarization vectors , but with the polarization tensors from eqs . , . this expression is lengthy and we will not give it in full detail . however , we will state it in a formal manner : @xmath294 where @xmath295 are photon polarization tensors and @xmath296 includes all parts that do not directly involve the photon : traces of combinations of @xmath297-matrices , electron propagators etc . the structure of @xmath298 is similar to eq . ( 5.81 ) of ref . however , the latter equation gives the sum over all polarizations , whereas @xmath298 is the amplitude square for a distinct polarization . for the configurations of table [ tab : compton - scattering - results1 ] and [ tab : compton - scattering - results2 ] the results are shown for different lorentz - violating parameters @xmath299 , where @xmath299 is defined by @xmath300 with @xmath60 of eq . . it suffices to give @xmath299 , since for both tables the three lorentz - violating parameters @xmath30 , @xmath31 , and @xmath32 are chosen to be equal . table [ tab : compton - scattering - results3 ] presents results , where the latter parameters differ from each other . compare the obtained results to the classical thomson cross section , which follows from the standard qed result first obtained by klein and nishina in the limit of vanishing initial photon momentum @xcite : @xmath301 from table [ tab : compton - scattering - results1 ] we see that for vanishing lorentz violation the gauge - invariant contributions from eq . are equal : @xmath302 furthermore , the sum of all cross sections then corresponds to the thomson limit given in eq . . the results for @xmath275 , @xmath276 , and @xmath277 do not depend on whether eq . or eq . is used for the calculation . from table [ tab : compton - scattering - results2 ] it also follows that , for vanishing lorentz violation , @xmath303 and , furthermore , that the averaged sum over all cross sections corresponds to the standard klein nishina results . besides , all results are independent of the fact of whether the calculation is based on @xmath304 or @xmath298 . this is also the case for the first selection of parameters in table [ tab : compton - scattering - results3 ] . furthermore , this table shows that the individual cross sections @xmath275 , @xmath276 , @xmath277 , and @xmath278 depend on the direction of @xmath54 , which is encoded in the choice of @xmath30 , @xmath31 , and @xmath32 . however , it is evident that the gauge - invariant expressions defined in eq . are independent of the direction of @xmath54 . plotting the matrix element squares @xmath304 from eq . and @xmath298 from eq . for each process @xmath279 , @xmath280 , @xmath281 , and @xmath282 leads to a surprise . we first present graphs of both @xmath304 and @xmath298 for different sets of lorentz - violating parameters , where the azimuthal angle @xmath271 is set to zero . , @xmath280 , @xmath281 , and @xmath282 for each row . the functions in the first row correspond to eq . , where the modified polarization vectors were plugged in . the panels in the second row show the corresponding function from eq . that is obtained by using polarization tensors instead of the polarization vectors directly . the plots were made for the special choice @xmath305 and the horizontal axis gives the polar angle @xmath270 . the lorentz - violating parameters are chosen as @xmath306 . furthermore , @xmath307 and @xmath40 . ] , @xmath280 , @xmath281 , and @xmath282 for each row . the functions in the first row correspond to eq . , where the modified polarization vectors were plugged in . the panels in the second row show the corresponding function from eq . that is obtained by using polarization tensors instead of the polarization vectors directly . the plots were made for the special choice @xmath305 and the horizontal axis gives the polar angle @xmath270 . the lorentz - violating parameters are chosen as @xmath306 . furthermore , @xmath307 and @xmath40 . ] , @xmath280 , @xmath281 , and @xmath282 for each row . the functions in the first row correspond to eq . , where the modified polarization vectors were plugged in . the panels in the second row show the corresponding function from eq . that is obtained by using polarization tensors instead of the polarization vectors directly . the plots were made for the special choice @xmath305 and the horizontal axis gives the polar angle @xmath270 . the lorentz - violating parameters are chosen as @xmath306 . furthermore , @xmath307 and @xmath40 . ] , @xmath280 , @xmath281 , and @xmath282 for each row . the functions in the first row correspond to eq . , where the modified polarization vectors were plugged in . the panels in the second row show the corresponding function from eq . that is obtained by using polarization tensors instead of the polarization vectors directly . the plots were made for the special choice @xmath305 and the horizontal axis gives the polar angle @xmath270 . the lorentz - violating parameters are chosen as @xmath306 . furthermore , @xmath307 and @xmath40 . ] , @xmath280 , @xmath281 , and @xmath282 for each row . the functions in the first row correspond to eq . , where the modified polarization vectors were plugged in . the panels in the second row show the corresponding function from eq . that is obtained by using polarization tensors instead of the polarization vectors directly . the plots were made for the special choice @xmath305 and the horizontal axis gives the polar angle @xmath270 . the lorentz - violating parameters are chosen as @xmath306 . furthermore , @xmath307 and @xmath40 . ] , @xmath280 , @xmath281 , and @xmath282 for each row . the functions in the first row correspond to eq . , where the modified polarization vectors were plugged in . the panels in the second row show the corresponding function from eq . that is obtained by using polarization tensors instead of the polarization vectors directly . the plots were made for the special choice @xmath305 and the horizontal axis gives the polar angle @xmath270 . the lorentz - violating parameters are chosen as @xmath306 . furthermore , @xmath307 and @xmath40 . ] , @xmath280 , @xmath281 , and @xmath282 for each row . the functions in the first row correspond to eq . , where the modified polarization vectors were plugged in . the panels in the second row show the corresponding function from eq . that is obtained by using polarization tensors instead of the polarization vectors directly . the plots were made for the special choice @xmath305 and the horizontal axis gives the polar angle @xmath270 . the lorentz - violating parameters are chosen as @xmath306 . furthermore , @xmath307 and @xmath40 . ] , @xmath280 , @xmath281 , and @xmath282 for each row . the functions in the first row correspond to eq . , where the modified polarization vectors were plugged in . the panels in the second row show the corresponding function from eq . that is obtained by using polarization tensors instead of the polarization vectors directly . the plots were made for the special choice @xmath305 and the horizontal axis gives the polar angle @xmath270 . the lorentz - violating parameters are chosen as @xmath306 . furthermore , @xmath307 and @xmath40 . ] , but now for the choice @xmath308 . ] , but now for the choice @xmath308 . ] , but now for the choice @xmath308 . ] , but now for the choice @xmath308 . ] , but now for the choice @xmath308 . ] , but now for the choice @xmath308 . ] , but now for the choice @xmath308 . ] , but now for the choice @xmath308 . ] in fig . [ fig : plots - matrix - element - square - parameter - choice-1 ] , for which @xmath306 was inserted , we see that @xmath304 corresponds to @xmath298 for the processes @xmath279 , @xmath280 , @xmath281 , and @xmath282 . the graphs in fig . [ fig : plots - matrix - element - square - parameter - choice-2 ] for lorentz - violating parameters @xmath308 indicate that for the @xmath282 process the amplitude square @xmath304 approaches @xmath298 , but there remains a residue , which appears for @xmath304 as a narrow peak at an angle @xmath309 ( given in arc measure ) . finally , in fig . [ fig : plots - matrix - element - square - parameter - choice-3 ] we depict @xmath304 and @xmath298 for the @xmath279 and the @xmath282 modified compton scattering as a function of both the polar angle @xmath270 and the azimuthal angle @xmath271 . it is evident that @xmath304 and @xmath298 for @xmath279 perfectly agree with each other . this is also the case for the processes @xmath280 and @xmath281 , but we will not display the corresponding plots here . however , the @xmath282 scattering behaves differently . the matrix element @xmath298 looks smooth and @xmath310 , respectively , probably originate from numerical errors ] , whereas for @xmath311 , the amplitude square @xmath304 is characterized by a set of sharp peaks . for small lorentz violation some of these peaks seem to remain . whether or not the limit for vanishing lorentz violation is influenced by such structures can not be investigated numerically , but requires analytical computations . and the azimuthal angle @xmath271 for compton scattering of polarized photons . the plots in the first row were made by using @xmath304 from eq . . the graphs in the second row illustrate @xmath298 from eq . . the first column illustrates the corresponding functions for the @xmath279 process with @xmath312 . the second and the third demonstrate the @xmath282 process , where @xmath312 and @xmath313 , respectively . here again holds @xmath307 and @xmath40 . ] and the azimuthal angle @xmath271 for compton scattering of polarized photons . the plots in the first row were made by using @xmath304 from eq . . the graphs in the second row illustrate @xmath298 from eq . . the first column illustrates the corresponding functions for the @xmath279 process with @xmath312 . the second and the third demonstrate the @xmath282 process , where @xmath312 and @xmath313 , respectively . here again holds @xmath307 and @xmath40 . ] and the azimuthal angle @xmath271 for compton scattering of polarized photons . the plots in the first row were made by using @xmath304 from eq . . the graphs in the second row illustrate @xmath298 from eq . . the first column illustrates the corresponding functions for the @xmath279 process with @xmath312 . the second and the third demonstrate the @xmath282 process , where @xmath312 and @xmath313 , respectively . here again holds @xmath307 and @xmath40 . ] and the azimuthal angle @xmath271 for compton scattering of polarized photons . the plots in the first row were made by using @xmath304 from eq . . the graphs in the second row illustrate @xmath298 from eq . . the first column illustrates the corresponding functions for the @xmath279 process with @xmath312 . the second and the third demonstrate the @xmath282 process , where @xmath312 and @xmath313 , respectively . here again holds @xmath307 and @xmath40 . ] and the azimuthal angle @xmath271 for compton scattering of polarized photons . the plots in the first row were made by using @xmath304 from eq . . the graphs in the second row illustrate @xmath298 from eq . . the first column illustrates the corresponding functions for the @xmath279 process with @xmath312 . the second and the third demonstrate the @xmath282 process , where @xmath312 and @xmath313 , respectively . here again holds @xmath307 and @xmath40 . ] and the azimuthal angle @xmath271 for compton scattering of polarized photons . the plots in the first row were made by using @xmath304 from eq . . the graphs in the second row illustrate @xmath298 from eq . . the first column illustrates the corresponding functions for the @xmath279 process with @xmath312 . the second and the third demonstrate the @xmath282 process , where @xmath312 and @xmath313 , respectively . here again holds @xmath307 and @xmath40 . ] we already know from eq . that the second polarization vector splits into two contributions : a transverse and a longitudinal part . for vanishing lorentz violation it is explicitly true that [ eq : polarization - vector-2-transversal - longitudinal - part ] @xmath314 @xmath315 if @xmath167 couples to a gauge - invariant quantity , its longitudinal part will vanish because of the ward identity , since it is directly proportional to the four - momentum @xmath316 . the weird structures appearing in the matrix element squared @xmath317 , which were discussed in the last section , originate from the longitudinal part of @xmath167 . as mentioned , from eq . it follows that in the limit of zero lorentz violation the longitudinal part vanishes by the ward identity when contracted with physical quantities . however , this only holds if the prefactor @xmath318 is not zero . otherwise , we run into a `` @xmath319 '' situation , which is mathematically not defined . now , the physical phase space of the process contains a sector , for which @xmath320 becomes arbitrarily small . this sector is characterized by two angles @xmath321 , where for @xmath322 , @xmath309 . this is depicted in fig . [ fig : zero - contour ] . , for which the normalization factor @xmath137 vanishes . the peaks in fig . [ fig : plots - matrix - element - square - parameter - choice-3 ] , lie on this contour . ] for this special case the normalization factor @xmath137 and , therefore , the prefactor @xmath318 can become arbitrarily small . this destroys the applicability of the ward identity and shows up as peaks in @xmath317 of figs . [ fig : plots - matrix - element - square - parameter - choice-2 ] and [ fig : plots - matrix - element - square - parameter - choice-3 ] . now we would like to analytically investigate the limit @xmath166 of the second polarization vector , with its transversal part subtracted . we distinguish between two cases , @xmath323 and @xmath324 . the first represents the phase space sector for compton scattering , for which @xmath63 becomes arbitrarily small . we begin with the zeroth component of eq . : @xmath325 the longitudinal part @xmath326 , which can be extracted from eq . as well , results in : @xmath327 \\ & = \mathcal{e}^2|\mathbf{k}|^4\big(1+\mathcal{e}\widehat{\mathbf{k}}\cdot\widehat{\boldsymbol{\zeta}}\big)\big(\widehat{\boldsymbol{\zeta}}-\widehat{\mathbf{k}}(\widehat{\mathbf{k}}\cdot\widehat{\boldsymbol{\zeta}})\big)^2\,\widehat{\mathbf{k } } \notag \displaybreak[0]\\ & = \mathcal{e}^2|\mathbf{k}|^4\big(1+\mathcal{e}\widehat{\mathbf{k}}\cdot \widehat{\boldsymbol{\zeta}}\big)\big(1-(\widehat{\mathbf{k}}\cdot\widehat{\boldsymbol{\zeta}})^2\big)\widehat{\mathbf{k } } \notag \displaybreak[0]\\ & = \mathcal{e}^2|\mathbf{k}|^4\left(1+\frac{\mathcal{e}k_{\parallel}}{|\mathbf{k}|}\right)\left(1-\frac{k_{\parallel}^2}{|\mathbf{k}|^2}\right)\widehat{\mathbf{k } } \notag \displaybreak[0]\\ & \sim\left\{\begin{array}{lcl } \mathcal{e}^2|\mathbf{k}|^2\big(|\mathbf{k}|^2-k_{\parallel}^2\big)\widehat{\mathbf{k } } & \text{for } & k_{\parallel}\gg \mathcal{e}k_{\bot}\ , , \displaybreak[0]\\ \mathcal{e}^2k_{\bot}^4\widehat{\mathbf{k } } & \text{for } & k_{\parallel}\sim \mathcal{e}k_{\bot}\ , . \end{array}\right.\end{aligned}\ ] ] the normalization factor from eq . is @xmath328 respecting @xmath324 , we obtain for the second polarization vector : @xmath329 which vanishes for @xmath166 . in contrast to the latter case , the result for @xmath323 is as follows : @xmath330 the latter diverges in the limit @xmath166 . hence , it becomes evident that for vanishing lorentz - violating parameter @xmath60 , when @xmath63 runs into the phase space sector where it becomes of the order of @xmath331 , a peak emerges . its width is then @xmath332 and its height is @xmath333 . this leads us undoubtedly to the following representation of a @xmath334-function as the limit of a function sequence : @xmath335 the role of the function sequence index @xmath336 in eq . is taken by the lorentz - violating parameter @xmath60 in the polarization vector . as a result , we finally obtain in the limit @xmath166 : @xmath337 this analytic result shows , besides the numerically obtained plots in figs . [ fig : plots - matrix - element - square - parameter - choice-2 ] and [ fig : plots - matrix - element - square - parameter - choice-3 ] , that the longitudinal part of the second polarization vector may still play a role for vanishing lorentz - violating parameter . because of the @xmath334-function , the ward identity can perhaps not be applied any more . now we want to look at the third term of eq . , which is enclosed by round brackets . it will be denoted as @xmath338 in what follows . we consider the @xmath282 scattering process , where for the polarization vector in the final state we insert only its longitudinal part according to eq . . note that the longitudinal part of the initial state polarization vector vanishes , since @xmath339 . then we obtain : @xmath340\\ & \sim k_{2,\bot}\delta(k_{2,\parallel})\begin{pmatrix } 0 \\ \widehat{\boldsymbol{\varepsilon}}^{(2)}(k_1 ) \\ \end{pmatrix}\cdot \begin{pmatrix } 1 \\ \widehat{\mathbf{k}}_2 \\ \end{pmatrix } \notag \displaybreak[0]\\ & \quad\,-\frac{k_{2,\bot}\delta(k_{2,\parallel})}{p_1\cdot k_1}\left[\begin{pmatrix } 0 \\ \widehat{\boldsymbol{\varepsilon}}^{(2)}(k_1 ) \\ \end{pmatrix}\cdot\begin{pmatrix } p_1 ^ 0 \\ \mathbf{p}_1 \\ \end{pmatrix}\right]\left[\begin{pmatrix } 1 \\ \widehat{\mathbf{k}}_2 \\ \end{pmatrix}\cdot \begin{pmatrix } p_2 ^ 0 \\ \mathbf{p}_2 \\ \end{pmatrix}\right ] \notag \displaybreak[0]\\ & \quad\,+\frac{k_{2,\bot}\delta(k_{2,\parallel})}{p_1\cdot k_2}\left[\begin{pmatrix } 0 \\ \widehat{\boldsymbol{\varepsilon}}^{(2)}(k_1 ) \\ \end{pmatrix}\cdot \begin{pmatrix } p_2 ^ 0 \\ \mathbf{p}_2 \\ \end{pmatrix}\right]\cdot \left[\begin{pmatrix } 1 \\ \widehat{\mathbf{k}}_2 \\ \end{pmatrix}\cdot \begin{pmatrix } p_1 ^ 0 \\ \mathbf{p}_1 \\ \end{pmatrix}\right ] \notag \displaybreak[0]\\ & = k_{2,\bot}\delta(k_{2,\parallel})\left[\widehat{\boldsymbol{\varepsilon}}^{(2)}(k_1)\cdot \widehat{k}_2-\frac{(\widehat{\boldsymbol{\varepsilon}}^{(2)}(k_1)\cdot \mathbf{p}_1)(p_2\cdot k_2)}{|\mathbf{k}_2|\,p_1\cdot k_1}+\frac{(\widehat{\boldsymbol{\varepsilon}}^{(2)}(k_1)\cdot \mathbf{p}_2)(p_1\cdot k_2)}{|\mathbf{k}_2|\,p_1\cdot k_2}\right ] \notag \\ & = k_{2,\bot}\delta(k_{2,\parallel})\left[\widehat{\boldsymbol{\varepsilon}}^{(2)}(k_1)\cdot \widehat{\mathbf{k}}_2-\frac{\widehat{\varepsilon}^{(2)}(k_1)\cdot \mathbf{k}_2}{|\mathbf{k}_2|}\right]=0\,,\end{aligned}\ ] ] where we have used @xmath341 . hence , the ward identity does not seem to care about the @xmath334-function . the contribution from the longitudinal part vanishes anyway . the conclusion is that the peaks in fig . [ fig : plots - matrix - element - square - parameter - choice-3 ] are most likely numerical artifacts . besides that , we expect this to hold also for the peaks in fig . [ fig : plots - matrix - element - square - parameter - choice-2 ] , where the lorentz - violating parameter has the finite value @xmath342 . in section [ sec : limit - polarizations - vanishing - lorentz - violation ] we have seen that preferred spacetime directions @xmath28 and @xmath29 appear in the polarization tensors @xmath295 even for vanishing lorentz violation . however , since the limit of @xmath298 for vanishing lorentz - violating parameters seems to coincide with the standard qed result , they obviously do not play a role for physical quantities . the question then arises as to why this is the case . we consider an amplitude @xmath343 , to which one external photon with four - momentum @xmath316 and polarization @xmath290 couples : @xmath344 . in what follows , the term `` matrix element squared '' is understood in the sense of individual contributions @xmath345 . for a virtual state , all polarization vectors , hence also the scalar and the longitudinal ones , contribute to the polarization - summed matrix element squared denoted as @xmath346 : @xmath347 evaluating @xmath346 for a real state means that the ward identity is used . for standard qed , if @xmath348 is chosen , the ward identity will result in @xmath349 from which it follows that @xmath350 or @xmath351 . because of this , the unphysical degrees of freedom cancel each other and what remains are terms which involve the physical polarization vectors ( @xmath110 , 2 ) . since the latter can be chosen as @xmath352 and @xmath353 , we obtain @xmath354 where ` phys ' means that the ward identity has been used . in order to understand the limits of the polarization tensors from eq . we will perform a similar analysis in the context of the modified theory . for @xmath355 with @xmath356 the ward identity reads @xmath357 and therefore , @xmath358 can be expressed as follows : @xmath359 @xmath360 where the ward identity has been used in the second step . hence , restricting the `` matrix element squared '' to the physical subspace with the ward identity guarantees that the additional parts , that depend on the preferred directions @xmath28 and @xmath29 , cancel . now consider the @xmath111 polarization mode . with eq . we obtain : @xmath361 setting @xmath146 in eq . results in @xmath362 and therefore @xmath351 . this then leads to @xmath363 hence , we see that by using the ward identity all contributions depending on @xmath28 and @xmath29 also vanish for the second mode . therefore , for vanishing lorentz violation the standard result @xmath364 is recovered . in this article , a special sector of a _ cpt_-even lorentz - violating modification of qed , with the characteristics of being parity - odd and nonbirefringent , was examined with respect to consistency . the deformation of qed is described by one fixed timelike `` four - vector '' , one fixed spacelike `` four - vector '' , and three lorentz - violating parameters . the nonbirefringent _ ansatz _ combined with the parity - violating parameter choice leads to two distinct physical photon polarization modes . these modes are characterized by dispersion relations , that differ to quadratic order in the lorentz - violating parameters . hence , the theory is only nonbirefringent to linear order . the dispersion relations coincide with the formulas previously obtained in ref . the new most important results of this article are summarized in the subsequent items : * with the optical theorem , unitarity is verified for tree - level processes involving conserved currents . * microcausality is established for the full range of lorentz - violating parameters . information only propagates along the modified null cones . * it has turned out that _ covariant _ polarization tensors can be constructed for each photon mode . this is not possible in standard qed , where only the polarization tensor of the sum of both modes can be written covariantly . * the gauge - invariant polarization tensor of each mode depends on the background field directions . for vanishing lorentz violation this dependence remains . it only cancels when considering the sum of both modes , which leads to the polarization sum of standard qed . * the fact that the polarization tensors depend on the background field directions even for vanishing lorentz violation , makes us think about the question of whether the limit of zero lorentz violation is continuous . in other words , _ a priori _ it is not clear , whether or not the modified theory approaches standard qed for vanishing lorentz violation . this is the motivation to test the theory via brute force by calculating one special process : compton scattering for unpolarized electrons scattered by polarized photons . * the cross sections can be computed either by using the modified polarization vectors or the modified polarization tensors . the upshot is that the results for @xmath279 , @xmath365 , and @xmath281 coincide , but a numerical treatment reveals a discrepancy for @xmath282 scattering . the ward identity is shown to cure the polarization vectors and tensors from their bad behavior for vanishing lorentz violation , at least for the first three processes . however , if the matrix element squared is computed for the fourth process by using the modified polarization vectors , there exists a phase space sector , for which the longitudinal part of the second polarization vector is proportional to a @xmath334-function . this could be shown by an analytic investigation . it could also be proven analytically that the ward identity can cancel this contribution , nevertheless . to conclude , the parity - odd `` nonbirefringent '' sector of modified maxwell theory seems with regard to the performed investigations to be consistent . further steps in the context of consistency of lorentz - violating quantum field theories may involve the analysis of unitarity at one - loop level , where the lorentz - violating structure is treated in an exact way . especially for this parity - odd theory it would be interesting to know if its consistency is inherited to higher orders of perturbation theory . however , this is beyond the scope of this article . in light of the consistency of this lorentz - violating extension at tree level , nature decides on the values of the lorentz - violating parameters . therefore , they have to be measured with experiments . for a summary of the current experimental status we refer to ref . @xcite and references therein . the latter article also gives new experimental bounds on the parity - odd parameters . we compute the cross section in two different manners . the first possibility is to follow sec . 11.1 of ref . @xcite , which gives the matrix element squared for compton scattering of polarized photons off unpolarized electrons . in order to derive this equation , the authors use polarization vectors . this is clear since in standard qed covariant polarization tensors can not be constructed from the polarization vectors . hence , we perform a similar calculation in the modified theory , where we can directly test our polarization vectors given by eqs . and . the second possibility is to compute the cross sections according to eq . ( 5.81 ) of ref . @xcite , where polarization tensors are used . note that here compton scattering of _ unpolarized _ photons is considered , hence it is averaged over initial and summed over final photon polarizations . only under this condition can polarization tensors be used in standard qed . however , for parity - odd `` nonbirefringent '' modified maxwell theory an analogous computation is also possible for compton scattering with polarized photons . hence , we have to calculate @xmath366 @xmath367 where the energy of the final electron is denoted as @xmath368 . note the division by the group velocity of the first and second polarization state ( see also ref . @xcite ) , respectively , where in the standard theory @xmath369 . the tensor @xmath370 is given by the trace term of eq . ( 5.81 ) of ref . @xcite with some modifications due to the lorentz - violating kinematics . lies along the third axis of the coordinate system . for the outgoing photon momentum @xmath371 , spherical coordinates are chosen with the azimuthal angle @xmath270 corresponding to the angle between @xmath371 and the third axis . cases are treated with the three - vector @xmath54 having equal or unequal components . ] the purely algebraic part of the calculation , that includes computation of traces , contraction of indices and inserting kinematical relations , is performed with ` form ` @xcite . the subsequent phase space calculation is done numerically with ` c++ ` , since the resulting matrix element squared contains hundreds of terms . the limit of zero lorentz violation has to be taken with care and `` long double '' precision does not suffice here . therefore , the gnu multiple precision arithmetic library ` gmp ` @xcite is used with its ` c++ ` interface described in sec . 12 of the reference previously mentioned . the first idea was to choose the coordinate system such that @xmath54 lies along the third axis . then the phase space should have been integrated with cylindrical coordinates @xmath372 . to cover a general situation , where the initial photon momentum @xmath373 points in an arbitrary direction , the cylindrical axes would have to point in that direction as well . as a result of this , the coordinate frame must be rotated in order to compute the cross section . this treatment has turned out to be unsuitable . therefore , a better approach is the following , which is sketched in fig . [ fig : phase - space - integration ] . the phase space integration is performed with spherical coordinates @xmath374 , where the initial photon momentum points along the third axis of the coordinate system . the general case is mimicked by @xmath54 pointing in an arbitrary direction . as a special but nevertheless very generic case we can choose its components to be equal ( however , computations were also done for different cases as shown in table [ tab : compton - scattering - results3 ] ) : @xmath375 the integration over @xmath376 is eliminated at once with the energy conservation equation in the @xmath334-function . here , we have to keep in mind that @xmath377 where @xmath378 is the corresponding zero . the analytic solution @xmath378 is a complicated function of @xmath60 and @xmath379 , so we determine it numerically with newton s method inside the ` c++ ` program . the integrations over @xmath270 and @xmath271 are performed with the simpson rule , which is sufficient for our purpose . the integration domain , that includes all physical states , is determined automatically with @xmath378 . if no zero @xmath378 exists , then the corresponding angles @xmath270 and @xmath271 lie outside the domain . the low - energy limit of the compton scattering cross section ( thomson limit ) can be calculated classically via the following equation ( see e.g. ref . @xcite ) : @xmath380 where @xmath381 is the polarization three - vector of the incoming and @xmath382 that of the outgoing electromagnetic wave . for the initial wave traveling along the @xmath207-axis we can choose the transverse polarization vectors as @xmath383 in general , the propagation direction of the final wave can be described in spherical coordinates by the basis vector @xmath384 . then we can pick the physical polarization vectors to point along the other two basis vectors @xmath385 and @xmath386 : @xmath387 this leads to the polarized thomson scattering cross sections in standard electrodynamics : @xmath388 if we rotate , for example , the set of initial polarization vectors by angle @xmath389 and the final ones by angle @xmath390 in their corresponding polarization planes , the single contributions @xmath391 will depend on @xmath390 . however , this dependence cancels in @xmath392 and @xmath393 that are defined as follows : @xmath394 @xmath395 from @xmath396 is clear that both initial modes deliver equal contributions to the total thomson result of eq . . this is also the case for mcs - theory . the mcs polarization tensors of eq . even give equal results for each individual polarized scattering process in the limit @xmath397 : @xmath398 for parity - odd modified `` nonbirefringent '' modified maxwell theory the individual contributions are not equal for @xmath166 . however , the above expressions from eqs . and correspond to each other . with eq . ( 11 - 13 ) of ref . @xcite and the standard polarization vectors from eq . we obtain the polarized compton scattering values given in table . 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there exist two deformations of standard electrodynamics that describe lorentz symmetry violation in the photon sector : _ cpt_-odd maxwell chern simons theory and _ cpt_-even modified maxwell theory . in this article , we focus on the parity - odd nonbirefringent sector of modified maxwell theory . it is coupled to a standard dirac theory of massive spin-1/2 fermions resulting in a modified quantum electrodynamics ( qed ) . this theory is discussed with respect to properties such as microcausality and unitarity , where it turns out that these hold . furthermore , _ a priori _ , the limit of the theory for vanishing lorentz - violating parameters seems to be discontinuous . the modified photon polarization vectors are interweaved with preferred spacetime directions defined by the theory and one vector even has a longitudinal part . that structure remains in the limit mentioned . since it is not clear , whether or not this behavior is a gauge artifact , the cross section for a physical process modified compton scattering is calculated numerically . despite the numerical instabilities occurring for scattering of unpolarized electrons off polarized photons in the second physical polarization state , it is shown that for lorentz - violating parameters much smaller than one , the modified cross sections approach the standard qed results . analytical investigations strengthen the numerical computations . hence , the theory proves to be consistent , at least with regard to the investigations performed . this leads to the interesting outcome of the modification being a well - defined parity - odd extension of qed .

improving golf performance has been a focus of research and development across various fields of sport expertise , including material engineering1 , golf course design2 , and sport exercise and training3,4,5,6 . performance in golf , as with other infield sports , such as baseball , for which concentration is required for accurate performance , has been shown to be closely related to physical conditioning4 . a high level of fitness is also an essential component for injury prevention in these sports7 . therefore , many studies are aiming to evaluate muscle strength and aerobic and anaerobic fitness levels in expert golfers . as the strength of a muscle is closely related to its cross - sectional area , in both health and disease8,9,10 , circumference measurements are commonly used as a proxy index of strength . as an example , measurements of the circumferences of the waist and mid - thigh have been used as proxy indexes of changes in trunk and lower limb strengths as indexes of changes in chronic diseases , such as diabetes and hypertension9,10,11,12 . another recent study reported a positive correlation between mid - thigh circumference and cardiovascular fitness13 . based on this evidence , it is reasonable to predict a positive relationship between mid - thigh circumference and lower limb muscle strength . thus , the mid - thigh circumference may be useful for evaluating the contribution of lower limb strength to golf performance . in a similar fashion , we predicted that waist circumference can be used to evaluate the contribution of trunk strength to golf performance . therefore , the aim of this study was to evaluate the relationships between waist and mid - thigh circumference , used as proxy measures of trunk and lower limb strengths , respectively , and selected parameters of driver and putting performance in college golfers in korea . the participants were 103 college golfers ( males , 81 ) aged 20 to 27 years . all anthropometric measurements and assessment of golf performance were conducted at the golf performance laboratory at konkuk university in chungju - si , republic of korea . the study conformed to the principles outlined in the declaration of helsinki and received clearance from the institutional review board of the korea national university of transportation ( knut irb-14 ) . the following anthropometric measures were obtained for all participants : body weight and percent body fat , which together provide an index of body composition , basal metabolic rate , grip strength , and waist and mid - thigh circumference . the following selected variables of golf performance were measured : average round score , driver distance , driver swing speed , putting accuracy , and putting consistency . body composition ( i.e. , percent body fat and basal metabolic rate ) was measured using standard impedance methods ( inbody 570 , biospace , seoul , republic of korea ) , based on the recommendations of the book applied body composition assessment14 . the resistance values of the arms , trunk , and legs were measured at frequencies of 1 , 5 , 50 , 256 , 512 , and 1,024 khz , using 8 tactile electrodes , 2 in contact with the palm and thumb of each hand , and 2 in contact with the anterior and posterior aspects of the sole of each foot15 . prior to impedance measurement , participants were instructed to not consume any drink or food for 4 h , to not exercise for 12 h , and to not urinate immediately before testing . participants wore light clothing , and all metal items , which could interrupt the electronic current during the measurement , were removed . the body mass index ( bmi ) for each participant was calculated as weight ( kg ) divided by height ( m ) squared ( kg / m ) . grip strength was measured with a hand grip dynamometer ( grip - d , takei , japan ) , with the elbow in the extended position . the peak value obtained over 3 trials , recorded to the nearest tenth of a kg , was used for analysis . the average round score ( i.e. , number of strokes in a round ) was determined from 10 rounds of golf played during the study period . driver distance ( yards ) and swing speed ( mph ) were recorded using a flightscope x2 golf simulator ( flightscope x2 , ver . 8.0.6 , flightscope , orlando , fl , usa ) , with the mean of 10 trials used for analysis for each variable . putting accuracy and putting consistency were calculated using a sam puttlab ( sam puttlab , ver . 2010 , science & motion sports gmbh , ruesselsheim , germany ) with the mean percentage ( % ) used for analysis . measurements of waist circumference were obtained at the half - distance between the lower costal margin and the iliac crest , with the participants standing with their feet 25 cm apart . mid - thigh circumference was measured at the half - distance between the greater tuberosity and the lateral condyle of the femur . for all measurements , the tape was held snugly to the limb , without compressing any underlying soft tissues . the relationships between the circumference of the waist and mid - thigh and measured performance variables were evaluated by partial correlation analysis , adjusting for effects of age , golf career , and bmi . statistical significance was set at p < 0.05 . the characteristics of the subjects are presented in table 1table 1.characteristics of the study groupvariablesmale ( n = 81)female ( n = 22)total ( n = 103)age ( years)22.4 2.121.7 1.422.2 2.0golf career ( years)6.1 3.46.6 3.36.2 3.4height ( cm)176.7 5.6162.6 4.7173.7 7.9weight ( kg)78.6 17.360.2 10.474.7 17.7body mass index ( kg / m)25.1 4.922.7 3.024.6 4.6basal metabolic rate ( kcal)1,708.8 133.61,288.0 91.51,618.9 213.9body fat ( % ) 19.2 7.028.4 6.421.2 7.8grip strength ( kg ) 44.7 6.827.6 4.941.1 9.5average round score ( stroke)83.2 6.283.0 5.383.1 6.0driver distance ( yards)257.1 28.9192.6 21.8243.3 38.2driver swing speed ( mph)103.7 7.684.7 5.699.6 10.6putting accuracy ( % ) 73.3 26.678.6 18.074.5 25.1putting consistency ( % ) 87.4 13.789.5 10.687.9 13.1waist circumference ( cm)85.5 11.775.8 8.083.4 11.7mid - thigh circumference ( cm)57.7 5.751.2 6.056.3 6.3data are presented as the mean sd . the results of the partial correlation coefficient analyses between waist and mid - thigh circumference and measured outcome variables of golf performance are reported in table 2table 2.partial correlation analysis between measured variables of golf performance and the circumferences of the waist and mid - thighvariablesmale ( n = 81)female ( n = 22)rrwc ( cm)grip strength0.062<0.001average round score0.1000.023driver distance0.0180.252driver swing speed0.0120.235putting accuracy0.0010.027putting consistency0.0670.165mc ( cm)grip strength0.0340.287average round score0.0840.093driver distance0.1370.197driver swing speed0.1300.162putting accuracy0.2050.547*putting consistency0.364**0.490**p < 0.05 and * * p < 0.01 ; tested by partial correlation analysis after adjusted age , golf career , and body mass index . waist circumference did not correlate with any of the performance variables in both males and females ( p > 0.05 ) . mid - thigh circumference correlated with putting consistency ( r = 0.364 , p = 0.001 ) in males and with putting consistency ( r = 0.490 , p = 0.033 ) and accuracy ( r = 0.547 , p = 0.015 ) in females . no other significant correlations between waist and mid - thigh circumference and golf performance were identified ( p > 0.05 ) . data are presented as the mean sd * p < 0.05 and * * p < 0.01 ; tested by partial correlation analysis after adjusted age , golf career , and body mass index . the purpose of this study was to examine the relationships between waist and mid - thigh circumference and sport performance of korean college golfers . a significant association between mid - thigh circumference and putting performance was identified , for both males and females . as we had predicted a priori , a direct relationship between driver distance and swing speed and the circumference of the waist or mid - thigh was not identified . this absence of a specific relationship between waist and mid - thigh circumference and driver performance likely indicates the importance of the whole body s contribution to driving the ball , including the trunk , legs , and arms , in combination with the characteristics of the golf club and overall motor control . the relationship between mid - thigh circumference and putting performance may reflect the specific importance of lower limb strength and stability to putting . the possible role of lower limb strengthening in improving putting performance is meaningful to the development of golfers , as lower limb strength is likely to be of benefit to overall performance in the short game around the green . while driver distance is an important component of golfing , short - game performance contributes significantly to the overall golf score16 . biomechanical and controlled studies are required to fully characterize the relationship between lower limb strength and golf performance , as well as to evaluate the role of lower limb strengthening in the training of golfers . first and foremost , the participants were recruited from only one university in chungju - si , republic of korea , and therefore may not be fully representative of all college golfers in korea . as well , the standard deviations for some variables were high within our relatively small group of participants , which could limit identification of statistical significance . therefore , while our results provide evidence of a possible role of lower limb strength on putting performance , further studies are needed to fully characterize the contributions of trunk and lower limb strengthening to performance of expert college golfers .

[ purpose ] our aim was to evaluate the relationships between waist and mid - thigh circumference , used as proxy measures of trunk and lower limb strengths , respectively , and selected parameters of driver and putting performance in korean college golfers . [ subjects and methods ] the participants were 103 college golfers ( 81 male , 20 to 27 years old ) . measurements of body composition , waist and mid - thigh circumference , and grip strength , as well as assessment of golf performance , including driver distance , driver swing speed , putting accuracy , and putting consistency , were performed at the golf performance laboratory at konkuk university in chungju - si , republic of korea . average round score was obtained from 10 rounds of golf completed during the study period . the relationships between strength measures and golf performance were evaluated by partial correlation analysis , with adjustment for age , golf experience , and body mass index . [ results ] waist circumference did not correlate with any of the performance variables in both males and females . mid - thigh circumference correlated with putting consistency ( r = 0.364 ) in males and with putting consistency ( r = 0.490 ) and accuracy ( r = 0.547 ) in females . no other significant correlations between waist and mid - thigh circumference and golf performance were identified . [ conclusion ] lower limb strength may be an important component of putting performance . further studies are needed to fully characterize the contributions of trunk strength to performance .

0 Teen on vacation survives nearly 10 hours in waters off St. Simons Island ST. SIMONS ISLAND, Ga. - A 19-year-old spent nearly 10 hours in the ocean fighting for his life. “Worst vacation ever, but also my most exciting ever,” said Blake Spataro. But it’s the kind of excitement we’d all like to avoid. “I was out there sitting by the shore when a rip tide washes me straight into the ocean,” he said. The teen was stranded in the ocean for nearly 10 hours. “I didn’t want to die out there. I was talking to God the entire night,” Spataro said. This 19-year-old spent nearly 10 HOURS in the ocean fighting for his life! “I was all alone with no one to talk to except myself and God.” The teen shares his remarkable story only to @ActionNewsJax at 10 pic.twitter.com/BHBBsC3o0i — Amber Krycka (@AmberANjax) July 12, 2018 He screamed for help, but no one heard him over the waves and wind. He said he continued to get pulled out to sea Tuesday night. “I wanted to live, I wanted to live, I was too young to die and I didn’t want it to end there,” said Spataro. For hours, the U.S. Coast Guard searched in the sky and by boat, along with multiple agencies. Spataro’s father, Kirk, spent all night walking up and down the beach, desperate to find his son. “I was screaming, I was hollering, I was looking,” Kirk Spataro said. Throughout the night, the 19-year-old did his best to stay calm. “Whenever I was tired I floated on my back,” he said. He was about to give up, but then came a ray of hope, literally. Lights from an approaching Coast Guard boat boosted his spirits. “That gave me some comfort and gave me some motivation to keep going,” he said. The teen kept pushing through until he came across a golf course early Wednesday morning where he came close enough to walk to shore and get help. Workers there gave him food and water until an ambulance arrived. “I’m alive,” the teen said. “I’ve been in the Coast Guard for 18 years and I have never seen anything like this,” said Justin Irwin, senior chief with the U.S. Coast Guard in Brunswick. Irwin visited the teen in his hospital room to let Spataro know how amazed and proud he was. “I am truly blessed to be alive today,” said Spataro. © 2018 Cox Media Group. ||||| Preliminary data on fatalities which occurred in the surf zones across National Weather Service areas of forecast responsibility through November 30, 2018. This data is preliminary and may not be completely accurate. Click on a state with surf zone fatalities in 2018 for a more detailed view. Rip Currents High Surf Sneaker Waves Other Unknown Rip Current High Surf Sneaker Wave Other Not Known Location ST M/F Age Date X Indian Sands Trail OR M 21 1/3 X Kamaole Beach Park HI M 50 1/18 X Near Depoe Bay OR M ? 1/18 X Kamaole Beach Park HI M 67 1/20 X Maluaka Beach HI M 71 1/27 X Oysterville Beach WA F 46 2/2 X Long Beach Peninsula WA F 61 2/2 X Ritidian Point GU M 38 2/13 X Coral Cove Park FL M 13 2/15 X Beacon Beach CA M ? 2/22 X Bob Hall Pier TX M 20 3/16 X Padre Island TX F 14 3/16 X Navarre Beach FL M ? 3/25 X Fort Morgan AL M 17 3/25 X Shark's Hole GU F 49 4/1 X Jupiter FL M 46 4/3 X Fredericksted VI ? ? 4/9 X Kitty Hawk Beach NC M 4 4/25 X Daytona Beach FL M 32 4/27 X6 College Creek Beach VA M 25 5/4 X Cocoa Beach FL F 40 5/5 X Saint Augustine Beach FL M 18 5/13 X Massengale Park Beach GA M 39 5/13 X Massengale Park Beach GA F 34 5/13 X Siesta Key FL M 59 5/18 X Panama City Beach FL M 5 5/19 X Panama City Beach FL M 31 5/25 X Miramar Beach FL M 28 5/25 X Horace Caldwell Pier TX F 52 5/30 X Panama City Beach FL M 61 5/31 X Buxton NC M 79 6/3 X Frisco NC M 55 6/6 X St. Joseph Peninsula FL M 38 6/3 X Ocracoke Island NC M 55 6/6 X Rockaway Beach OR M 50 6/6 X Rockaway Beach OR M 17 6/6 X Pacific Beach CA M 26 6/12 X Atlantic Beach NC M 48 6/15 X Panama City Beach FL M 67 6/16 X Lido Key Beach FL M ? 6/17 X M.B. Miller County Pier FL M 21 6/17 X Panama City Beach FL M 15 6/19 X Panama City Beach FL M 60 6/19 X Long Beach NY M 10 6/19 X2 Gilchrist TX M 34 6/26 X Avon NC M 48 6/28 X2 Pennover Park WI M 38 6/30 X Cowell Beach CA F 47 7/1 X Surf City Beach NJ M 55 7/4 X Areicibo PR M 29 7/4 X Magens Bay, St. Thomas VI M 40 7/4 X4 Loyola Beach IL F 13 7/6 X Kill Devils Hill NC M 62 7/7 X Ocean Grove Beach NJ M 42 7/9 X Ormond-By-The-Sea FL M 61 7/11 X Duck NC F 43 7/13 X Southern Shores NC M 32 7/19 X Holden Beach NC M 20 7/21 X Wrightsville Beach NC M ? 7/21 X Sunset Beach NC M ~40 7/21 X Condado Beach PR M 17 7/22 X Emerald Isle NC M 41 7/25 X Okaloosa Island FL M 19 8/1 X Dauphin Island AL M 17 8/2 X Dauphin Island AL M 47 8/2 X Miami Beach FL M 35 8/2 X Cocoa Beach FL M 50 8/5 X Destin Beach FL M 53 8/5 X Opal Beach FL M 41 8/5 X Emerald Isle NC M 40 8/5 X Grand Haven State Park MI M 64 8/5 X Grand Haven State Park MI M 20 8/5 X Bogue Sound NC M 29 8/10 X Waukegan Harbor IL M 14 8/17 Indiana Dunes State Park IN M 10 8/18 X Indiana Dunes State Park IN M 14 8/18 X Seabrook Beach NH M 49 8/19 X Seabrook Beach NH F 47 8/20 X Geneva-On-The Lakes OH M 20 8/20 Walnut Beach OH M 16 8/21 X X1 Myrtle Beach SC M 41 8/24 X1 Myrtle Beach SC M 73 8/24 X Kenosha WI M 17 9/6 X Playalinda Beach FL M 24 9/10 X Seaside Heights NJ M 44 9/15 X Rockaway Beach NY M 17 9/15 X Ballston Beach MA M 27 9/29 X Rodanthe MC M 63 10/1 X Trunk Bay, St. John VI M 67 10/2 X Assateague State Park MD M 18 10/7 X Assateague State Park MD M 57 10/7 X St. Petersburg FL F 36 10/13 X Galveston Beach TX M 11 10/14 X Galveston Beach TX M 16 10/14 X Jamestown RI M ? 10/28 X Jamestown RI F ? 10/28 59 20 0 14 4 Total: 97 1: longshore current, 2: tidal current, 3: outlet current, 4: structural current, 5: shore break, 6: strong current , 7. channel current *American Samoa, ? : unknown Accurately tracking these types of fatalities is difficult because so many go unreported and undocumented. Due to the difficult nature of tracking surf zone fatalities; these data may not match other sources. Surf Zone: area of water between the high tide level on the beach and the seaward side of the breaking waves. The NWS officially categorizes surf zone fatalities caused by three types of hazards; Rip Current, High Surf and Sneaker Wave (see definitions below). area of water between the high tide level on the beach and the seaward side of the breaking waves. The NWS officially categorizes surf zone fatalities caused by three types of hazards; Rip Current, High Surf and Sneaker Wave (see definitions below). Rip Current : A relatively small-scale surf-zone current moving away from the beach. Rip currents form as waves disperse along the beach causing water to become trapped between the beach and a sandbar or other underwater feature. The water converges into a narrow, river-like channel moving away from the shore at high speed. : A relatively small-scale surf-zone current moving away from the beach. Rip currents form as waves disperse along the beach causing water to become trapped between the beach and a sandbar or other underwater feature. The water converges into a narrow, river-like channel moving away from the shore at high speed. High Surf: Large waves breaking on or near the shore resulting from swells spawned by a distant storm. Large waves breaking on or near the shore resulting from swells spawned by a distant storm. Sneaker Wave: Large wave that suddenly swamps a beach/coast and takes people by surprise sweeping them into the water. Occasionally, there are surf zone fatalities caused by other hazards such as unusual waves and currents. These hazards fall in the “Other” category. “Other” is not an official category defined by the NWS. Rip Currents cause a large of percentage of the surf zone fatalities in the United States. Typically, a victim of a surf zone hazard is a male between the ages of 10-29. Most of the fatalities occur during the months of June and July and in the NWS Southern Region. NWS started tracking these statistics in 2013. We do not have breakdowns before 2013.

– A teen on vacation in Georgia was swept away by a riptide and managed to survive for a remarkable 10 hours in the ocean. Blake Spataro credits his faith and his dogged will to stay alive before he was finally able to make it to shore. "I wanted to live. I was too young to die," the 19-year-old tells Action News Jax. US Coast Guard personnel had spent hours searching for Spataro, who was on vacation on Georgia's St. Simons Island with his family. His father walked the beach all night Tuesday. They finally found the relief they were after when employees at the golf course where Spataro came ashore Wednesday morning called authorities, after giving him food and water. While Spataro's harrowing ordeal has a happy ending, not everyone caught in a rip tide survives. Since the start of 2018, the National Weather Service estimates at least 15 US fatalities have been blamed on the phenomenon.

Moscow (CNN) -- The Russian space agency on Monday postponed the launch of a new manned mission to the International Space Station due to last week's accident in which an unmanned cargo craft was lost, the state news agency RIA Novosti reported. Alexei Krasnov of the space agency, Roscosmos, said the next manned mission, originally planned to launch on September 22, now would occur in late October or early November, according to the RIA Novosti report. In the United States, NASA's space station program manager told reporters Monday that the timing of the rescheduled mission could force the temporary de-manning of the space station later this year. However, the NASA official, Mike Suffredini, said no decisions can be made until a commission appointed by Russia completes its investigation of the August 24 crash involving a Soyuz rocket -- the same kind used to power the flights of crew members to the space station. With a planned rotation of the six crew members aboard the space station scheduled to begin next month, a delay in using the Soyuz could prevent the ability to bring replacements, Suffredini said. "If we don't have Soyuz flying by the middle of November -- the 16th or so, the normal landing time for the last crew -- we would have to de-man ISS at that point," Suffredini said. The six astronauts at the space station are three from Russia, two from the United States and one from Japan. Due to the schedule change announced Monday, the three Russian astronauts on board will return to Earth eight days later than originally planned, on September 16 instead of September 8, Krasnov said. They will fly a Soyuz vehicle already at the space station. Suffredini said another Soyuz vehicle at the space station, which is set to fly back the other three crew members, will have its certification for the return mission expire by mid-November. If there can't be a new manned mission from Earth by then, administrators will have to decide whether to take extensive steps to extend the vehicle's certification for the return flight, proceed on a return flight without certification, or de-man the space station by flying back the remaining crew members within the certification period, he said. "We're going to do what's safest for the crew and for the space station," Suffredini said. He acknowledged that leaving the space station without any crew members increased the risk for trouble. "There is a greater risk of losing the ISS when it's unmanned than if it were manned," Suffredini said, adding that the risk increase "is not insignificant." The commission in Russia investigating last week's accident will determine the new launch date for the next manned mission, Krasnov said, according to the RIA Novosti report. Prior to that mission, Roscosmos will make two unmanned Soyuz launches, "either an automated one or a freighter or both," he said. On August 24, a Progress M-12M space freighter carrying food and other items to the space station broke up over southern Siberia after failing to separate from its Soyuz-U carrier rocket, RIA Novosti reported. It was the first loss of a Progress freighter in more than 30 years of operation, according to the report, which said the cause was believed to be a rocket engine failure. However, it was the second failed space launch in Russia in less than 10 days. On August 18, Russia lost a sophisticated Express-AM4 telecommunications satellite when the launch vehicle put it into the wrong orbit. The Progress M-12M that went down last week was to deliver more than 3.8 tons of cargo to the space station crew, including food supplies, medical equipment, personal hygiene items and scientific equipment needed for experiments, according to Roscosmos and space officials. Suffredini said Monday that space station crew is well-supplied due to the delivery of goods by the final U.S. shuttle mission carried out by Atlantis last month. NASA is now reliant on the Russian space agency to ferry U.S. astronauts to orbit, since the grounding of the U.S. shuttle fleet has left the United States with no way to lift humans into space. Plans are in the works for private companies to begin shipping cargo to the station, and eventually to carry astronauts as well. CNN's Tom Cohen contributed to this report. ||||| Sunlight glints off the International Space Station with the blue limb of Earth providing a dramatic backdrop in this photo taken by an astronaut on the shuttle Endeavour just before it docked after midnight on Feb. 10, 2010 during the STS-130 mission. This story was updated at 12:30 p.m. EDT. The International Space Station may have to start operating without a crew in November if Russian engineers don't figure out soon what caused a recent rocket failure, NASA officials announced today (Aug. 29). The unmanned Russian cargo ship Progress 44 crashed just after its Aug. 24 launch to deliver 2.9 tons of supplies to the orbiting lab. The failure was caused by a problem with the Progress' Soyuz rocket, which is similar to the one Russia uses to launch its crew-carrying vehicle — also called Soyuz — to the station. Currently, six astronauts reside on the space station. They shouldn't be unduly affected by the Progress crash, NASA officials said, because they have enough supplies to last a while on orbit. But three of these astronauts are due to return to Earth next month, and the rest are scheduled to come back in mid-November. At the moment, the Soyuz is the only way to get astronauts to and from the station. So if the rocket anomaly isn't identified and fixed soon, a fresh crew won't be able to reach the orbiting lab before the last three spaceflyers head for home. [Photos: Building the International Space Station] Unmanned for the first time in a decade? That situation would leave the $100 billion orbiting lab unmanned for the first time since 2001. Still, it wouldn't be a disaster, according to NASA officials. "We know how to do this," NASA's space station program manager Mike Suffredini told reporters today. "Assuming the systems keep operating, like I've said, we can command the vehicle from the ground and operate it fine, and remain on orbit indefinitely." NASA would of course prefer to keep some crew aboard the orbiting lab, Suffredini added. Leaving the station unmanned would cut back significantly on the scientific research being done 240 miles (386 kilometers) above the Earth. In the wake of the space shuttle's retirement last month, NASA has repeatedly stressed the importance of that research, and the scientific potential of the station. But the timing just might not work out. Two Soyuz spacecraft are currently docked to the station to take its six astronauts home. The vehicles are only rated to spend about 200 days in space, so they'll have to depart soon. [How Russia's Progress Spaceships Work (Infographic)] A Russian Soyuz rocket launches the unmanned Progress 44 cargo ship from Baikonur Cosmodrome on Aug. 24, 2011 to deliver fresh supplies to the International Space Station. The rocket and spacecraft crashed in eastern Russian just over five minutes after liftoff. Credit: RSC Energia Light at the landing site Lighting conditions at the Soyuz's Kazakhstan landing site are also an issue. NASA and the Russian space agency mandate that landings must occur at least one hour after dawn and one hour before dusk, to facilitate better search and rescue operations should any be required. The lighting window closes for about five weeks on Sept. 19 for the first crew and around Nov. 19 for the second. Waiting for a new window to open would stretch the Soyuz spacecraft beyond their 200-day ratings in both cases, Suffredini said. So all six astronauts on the space station will almost certainly have left the orbiting lab by mid-November. Russian engineers are working hard to give crewed Soyuz launches the best chance to meet that deadline; the next one is slated to blast off Sept. 21, but that's almost certainly not going to happen, Suffredini said. Russia has formed a commission to determine the cause of the Progress crash, and to figure out how to fix it. But NASA says it won't rush anything, as astronaut safety is its chief priority. "We'll just see how it plays out," Suffredini said. NASA won't put any crews on a Soyuz until the rocket has had several successful unmanned launches, he added. Those could happen relatively soon. Russia plans to use Soyuz boosters to launch a commercial payload and another Progress supply ship by late October. The Progress crash marked the latest in a string of Russian launch failures over the last 10 months. This series of mishaps has caused some concern among U.S. lawmakers and experts, since NASA will rely on Russia to loft its astronauts to orbit until private American crew-carrying spaceships come online. That could start happening by 2015, officials have said. You can follow SPACE.com senior writer Mike Wall on Twitter: @michaeldwall. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

– The failure of a Russian spaceship, which crashed back to Earth shortly after its launch last week, could lead to the International Space Station being unmanned for the first time since 2001. Russian engineers are trying to determine why the unmanned ship crashed, but they only have a short time to fix the problem if they want to relieve the six astronauts currently on the space station: All are scheduled to rotate home by November, Space.com reports, and NASA won’t allow any astronauts on a Soyuz rocket until the problem has been solved and several unmanned launches have been successful. While those six astronauts won’t be affected much by the crash itself—they have enough supplies—three are due to return home next month, and the other three by mid-November, and several factors prevent them from extending their stays. Russia’s space agency originally planned to launch a manned mission Sept. 22, but that has now been postponed until late October or early November due to the failed launch, CNN adds. Even if the delay prevents a new crew from reaching the station, NASA officials say they will be able to operate it from the ground and “remain on orbit indefinitely.”

pulmonary macrophages consist of several subpopulations that can be defined by their anatomical locations as well as by other criteria . in addition to the well - known alveolar macrophages that reside on the alveolar surface , pulmonary macrophages also occur in the conducting airways , in various pulmonary interstitial regions , and , in some mammalian species , in the lung 's intravascular compartment . other thoracic macrophages of relevance to pulmonary defense and some lung disease processes are the pleural macrophages resident in the pleural space and macrophages present in regional lymph nodes that receive lymphatic drainage from the lung . of the above subpopulations of pulmonary and thoracic macrophages , the alveolar macrophages have received the most experimental attention in the context of the pulmonary clearance and retention of deposited particles . accordingly , less information is currently available regarding the roles other pulmonary and thoracic populations of macrophages may play in the removal of particles from the lower respiratory tract and associated tissue compartments . this report provides an overview of the various subpopulations of pulmonary and thoracic macrophages , as defined by their anatomical locations . the known and postulated roles of macrophages in the pulmonary clearance and retention of particles are reviewed , with particular emphasis on macrophage - associated processes involved in the pulmonary clearance of relatively insoluble particles.imagesfigure 1.figure 2.figure 3.figure 5.figure 8.figure 12.figure 14.figure 15.figure 16.figure 17.figure 18.figure 19 . afigure 19 . bfigure 21.figure 22 .

in the past several years there has been a breakthrough , associated with the efforts of a theoretical collaboration at los alamos@xcite but with important antecedents@xcite , on the problem of the molecular theory of hydrophobic effects . that breakthrough is the justification for this review . one unanticipated consequence of that work has been the clarification of the ` pratt - chandler theory'@xcite . judged empirically , that theory was not less successful than is typical of molecular theories of liquids . but the supporting theoretical arguments had never been compelling and engendered significant confusion . that confusion was signaled already in 1979 by the view@xcite : `` the reason for the success of their theory may well be profound , but could be accidental . we can not be sure which . '' today the correct answer is ` both , ' though accidental first . in an amended form , it is a compelling theory . in reviewing these developments , a significant volume of intervening theoretical work must eventually be viewed again in this new light . in addition , the work that clarified the pratt - chandler theory suggested several improvements and extensions , and was deepened by the parallel development of the molecular quasi - chemical theory of solutions@xcite . on this basis , i predict an extended period of consolidation of the theory of these systems and inclusion of more realistic , interesting , and exotic instances . an attitude of this review is to respect a scholarly patience in addressing the foundations without prejudging the speculations ellicited by the fascinating biophysical motivations . thus , physical chemists working at strengthening those foundations are the audience for this review . nevertheless , clarity of the biophysical goals is important . thus , an uncluttered expression of the motivation and the basic problem is essential . the molecular theory of hydrophobic effects is an unsolved facet of a molecular problem foundational to biophysics and biochemistry : the quantitative molecular scale understanding of the forces responsible for structure , stability , and function of biomolecules and biomolecular aggregates . i estimate that the term ` hydrophobic ' appears in every biophysics and biochemistry textbook . an intuitive definition of hydrophobic effects is typically assumed at the outset . hydrophobic effects are associated with demixing under standard conditions of oil - like materials from aqueous solutions . a more refined appreciation of hydrophobic effects acknowledges that they are a part of a subtle mixture of interactions that stabilize biomolecular structures in aqueous solution over a significant temperature range while permitting sufficient flexibility for the biological function of those structures . preeminent characteristics of these hydrophobic interactions are temperature dependences , and concurrent entropies , that can be exemplified by cold denaturation of soluble proteins@xcite . if hydrophobic effects stabilize folded protein structures , then folding upon _ heating _ suggests that hydrophobic interactions become _ stronger _ with increasing temperature through this low temperature regime . this is a counter - intuitive observation . a primitive correct step in relieving this contrary intuition is the recognition that water molecules of the solution participate in this folding process@xcite . specific participation by small numbers of water molecules is not unexpected but also is nt the mark of hydrophobic effects . for hydrophobic effects , on the contrary , a large collection of water molecules are involved nonspecifically . it is the statistics of the configurations of these water molecules at the specified temperature that lead to the fascinating entropy issues . because of the significance of these entropies , hydrophobic effects are naturally a topic for molecular statistical thermodynamics . given the acknowledged significance of this topic , it is understandable that the literature that appeals to them is vast . many researchers from a wide range of backgrounds and with a wide variety of goals have worked on these problems . thus , the ` unsolved ' assertion will challenge those researchers . but the ` unsolved ' assertion also reflects a lack of integration of principles , tools , and results to form a generally accepted mechanism of hydrophobic effects . for example , it is widely , but not universally , agreed that the hydrogen bonding interactions between water molecules are a key to understanding hydrophobic effects . conventional molecular simulation calculations with widely accepted molecular interaction models for small hydrophobic species in water broadly agree with experimental results on such systems@xcite . in this sense , everything is known . nevertheless , this complete knowledge hasnt achieved a consensus for a primitive mechanism of hydrophobic effects . by ` mechanism ' we mean here a simpler , physical description that ties together otherwise disparate observations . though this concept of mechanism is less than the complete knowledge of simulation calculations , it is not the extreme ` poetic `` explanation ' '' famously noted by stillinger@xcite . the elementary simplifications that lead to a mechanism must be more than rationalizations ; they must be verifiable and consistent at a more basic level of theory , calculation , and observation . the ` breakthrough ' mentioned in the first paragraph is particularly exciting because it hints at such a mechanism for the most primitive hydrophobic effects . a great deal more reseach is called for , certainly . but discussion of that development is a principal feature of this review . the breakthrough required a couple steps . the first step was the realization that feasible statistical investigations of spontaneous formation of atomic sized cavities in liquid solvents should shed light on operating theories of hydrophobic hydration@xcite . those studies could be based upon the formal truth@xcite @xmath0 where @xmath1 is the interaction contribution to the chemical potential of a hard core hydrophobic solute of type a , and @xmath2 the probability that an observation volume defined by the excluded volume interactions of a with water molecules would have zero ( 0 ) occupants . these cavity formation studies were not an attempt to calculate hydration free energies for realistic hydrophobic solutes . the goal was just to examine simple theories and to learn how different solvents might be distinguished on this basis . there was also a significant physical idea alive at the time those studies were undertaken@xcite : `` the low solubility of nonpolar solutes in water arises not from the fact that water molecules can form hydrogen bonds , but rather from the fact that they are small in size . '' as a simple clear hypothesis , this view contributed to the breakthrough although the hypothesis was eventually disputed@xcite . packing and molecular sizes are important concerns for liquids because they are dense . the idea was that since water molecules are smaller than , say , ccl@xmath3 molecules , the ` interstitial ' spaces available in liquid water would be smaller than those in liquid ccl@xmath3 . the first disputed point was that this hypothesis was suggested by the approximate scaled particle model@xcite and that model was known to have flaws@xcite as applied to hydrophobic hydration . the second disputed point was that treatment of the coexisting organic phase , liquid ccl@xmath3 in this discussion , was less convincing than the treatment of liquid water : the modeling of a ccl@xmath3 molecule as a simple ball is an oft - convenient canard but should nt be taken too literally . another significant consideration is that liquid water is less dense on a packing fraction basis than most coexisting organic solvents . eventually@xcite , the direct investigations at the low pressures of first interest indicated that the probable spontaneously occurring cavities might be smaller in typical organic solvents than in water , though the differences are small . what was decidedly different between water and organic solvents was the flexibility of the medium to open cavities larger than the most probable size . water is _ less _ flexible in this regard , stiffer on a molecular scale , than typical organic liquids . 1 gives a macroscopic experimental perspective on this relative stiffness . furthermore , the results for the organic phase were not at all similar to what scaled particle models suggested@xcite . so as an explanation of the distinction between water and common organic solvents , the ` small size ' mechanism must be discounted@xcite . nevertheless , we can anticipate subsequent discussion by noting that the equation of state of the solvent is important in establishing thermodynamic signatures of hydrophobic hydration . as an analysis tool for assessment of packing in disordered phases , studies of cavity statistics should be more widely helpful@xcite . the interesting work of kocher , _ et al . _ , @xcite is notable . those calculations studied the cavity formation work in protein interiors and that cavity formation work was seen to be larger than for comparable organic solvents . in that respect , the packing of those protein interiors was tighter , less flexible , than a simple oil droplet . this conclusion seems significant for our pictures of protein structures and deserves further investigation . structural and compositional heterogeneity are undoubtedly also important features of the cores of globular proteins . these observations should be helpful in distinguishing the interiors of micelles from the cores of folded globular proteins@xcite . the decisive second step in achieving the present breakthrough was the modeling of the distribution @xmath4 of which @xmath2 is the n=0 member@xcite . several specific distributions @xmath4 had been tried in analyzing the results of pratt and pohorille@xcite . but it was eventually recognized that a less specific approach , utilizing a maximum entropy procedure to incorporate successively more empirical moment information , was prudent and effective . surprisingly , direct determination of the distribution @xmath4 showed that a two moment model @xmath5 was accurately born - out in circumstances of computer simulation of liquid water@xcite . the parameters @xmath6 are evaluated by fitting of the predicted moments @xmath7 , j = 0 , 1 , @xmath8 to moment data . a practical virtue of this two moment model is that the required moment data can be obtained from long - available experimental results . a further surprise was that it had previously been shown , in different contexts and with additional assumptions@xcite , that theories of a percus - yevick analog type had a structure derivable from a gaussian or harmonic density field theory . the pratt - chandler theory was of this percus - yevick analog type . to the extent that the empirical observation eq . [ gaussian ] suggests a normal distribution , the pratt - chandler theory is given a better foundation than was available at its genesis@xcite . in fact , the two moment model eq . [ gaussian ] is _ not _ precisely the same as the pratt - chandler theory . there are several related direct observations that can make that point clear . for example , the probability model eq . [ gaussian ] assigns probability weight only to non - negative integer occupancies . that is not the case for the harmonic density field theory . the restriction that such density field theories should not permit the negative occupancy of any subvolume is an obvious but interesting requirement . additionally , the percus - yevick theory for hard sphere mixtures can predict _ negative _ probabilities@xcite . these are technical issues , however , and the performance of the two moment model eq . [ gaussian ] gives strong and unexpected support for the pratt - chandler theory . there is a different respect in which the correspondence of the two moment model eq . [ gaussian ] with the pratt - chandler theory is imprecise . the kinship indicated above is based upon calculation of hydration free energies when the solvent can be idealized as a harmonic density field . that can be straightforwardly carried over to consideration of nonspherical solutes . for example , classic potentials of mean force might be addressed by consideration of a diatomic solute of varying bond length . the pratt - chandler theory does not do that directly but utilizes the structure of the ornstein - zernike equations together with yet another percus - yevick style closure approximation . those distinctions have not yet been discussed fully . a curious feature of the @xmath9 moment modeling is that convergence of predictions for @xmath10 with increasing numbers of utilized moments is non - monotonic@xcite . the predicted thermodynamic results are surprisingly accurate when two moments are used but become worse with three moments before eventually returning to an accurate prediction with many more moments available . the two moment model , and also the pratt - chandler theory , is fortuitous in this sense . but this does conform to the adage that ` good theories are either gaussian or everything . ' the theory above has always been understood at a more basic level than the description above@xcite . the most important observation is that the mayer - montroll series@xcite can be made significantly constructive with the help of simulation data@xcite and those approaches can be more physical than stock integral equation approximations . simulation data can provide successive terms in a mayer - montroll series . in that case the binomial moments @xmath11 are the stylistically preferred data@xcite . then the maximum entropy modeling is a device for a resummation based upon a finite number of initial terms of that series@xcite . several additional technical points are helpful at this level . the adage that ` good theories are either gaussian or everything ' is serious but does nt address the physical reasons why these distributions are the way they are . in fact , painstaking addition of successive moments is not only painful but often unsatisfying . and the two moment model eq . [ gaussian ] has been less satisfactory for every additional case examined carefully beyond the initial one that was connected with this breakthrough@xcite ; recent examples can be seen in ref . it is better to consider simple physical models for the distribution @xmath4 and approximations @xmath12 \approx \zeta_0 + \zeta_1 n + \zeta_2 n^2 + \ldots \label{dmodel}\end{aligned}\ ] ] where @xmath13 is a model distribution chosen on the basis of extraneous considerations . since @xmath14 in the absence of further information , @xmath13 is called the default model . utilization of a default model in this way compromises the goal of predicting the distribution and instead relies on the moments to adapt the default model to the conditions of interest . the default model of first interest@xcite is @xmath15 this default model produces the uncorrelated result ( the poisson distribution ) when the only moment used is @xmath16 . another way to identify default models is to use probabilities obtained for some other system having something in common with the aqueous solution of interest@xcite . an important practical point is that this approach works better when the default model is not too specific@xcite . this can be understood as follows : the moment information used to adapt the default model to the case of interest is not particularly specific . if the default model makes specific errors , a limited amount of that nonspecific data will not correct those errors adequately . this argument gives a partial rationalization for the accurate performance of the flat default model that leads to eq . [ gaussian ] . in eq . [ gaussian ] @xmath17 but it is helpful to notice that this thermodynamic quantity can be alternatively expressed as@xcite @xmath18 \right\ } \label{eq : pf}\end{aligned}\ ] ] where binomial moments through order @xmath19 are assumed and the default model is included . @xmath20 does not appear on the right since that normalization factor is being expressed through the thermodynamic property . the point is that this is a conventional form of a partition function sum . the interactions are n - function interactions , in contrast to density or @xmath21-functional theories , but with strength parameters adjusted to conform to the data available . the fact that @xmath1 is extracted from a fully considered probability distribution , and this consequent structure , is the substance behind our use of the adjective ` physical ' for these theories . these theories are still approximate , of course , and they will not have the internal consistency of statistical mechanical theories obtained by exact analysis of a mechanical hamiltonian system . the quasi - chemical theory@xcite adapted to treat hard core solutes@xcite gives an explicit structure for the @xmath1 formula as in eq . [ eq : pf ] . that result can be regarded as a formal theorem @xmath22~. \label{hsqca}\end{aligned}\ ] ] the @xmath23 are equilibrium ratios @xmath24 for binding of solvent molecules to a cavity stencil associated with the aw excluded volume , understood according to the chemical view @xmath25 @xmath26 is a precisely defined cavity species@xcite corresponding to the aw excluded volume . eq . [ eq : pf ] should be compared to eq . [ hsqca ] ; because of the structural similarity , it is most appropriate to consider eq . [ eq : pf ] as a quasi - chemical approximation . the @xmath23 are well - defined theoretically@xcite and observable from simulations . so again this approach can be significantly constructive when combined with simulations@xcite . but the first utility is that the low density limiting values of @xmath23 , call them @xmath27 , are computable few body quantities@xcite . the approximation @xmath28 \label{pqca}\end{aligned}\ ] ] is then a simple physical theory , the primitive quasi - chemical approximation@xcite . the lagrange multiplier @xmath29 serves as a ` mean field ' that adjusts the mean occupancy to the thermodynamic state of interest . for a hard sphere solute a in a hard sphere solvent , this theory produces sensible results though it does not achieve high accuracy in the dense fluid regime @xmath30@xcite where @xmath31 is the diameter of the solvent hard spheres . [ the foremost questions for aqueous solutions are at the lower boundary of this conventional demarcation of dense fluids . ] when the accuracy of this theory for hard sphere systems degenerates , it is because the distribution @xmath32 is too broad in the low n extreme@xcite ; see fig . because this theory thus directly treats short range molecular structure but somewhat too broadly , it is a natural suggestion for generating default models . no direct experience along those lines is presently available . the investigation of how such a simple theory breaks eq . [ cluster - var ] down is a yet more interesting aspect of the development of the quasi - chemical theories for these problems@xcite . for the hard sphere fluid at higher densities the primitive quasi - chemical theory eq . [ cluster - var ] remains a faithful descriptor of the n@xmath331 features of the distribution . but the actual @xmath2 ( see fig . 2 ) becomes depressed relative to the model ; @xmath2 breaks away from the rest of the primitive quasi - chemical distribution . in fact , the suggested correlation correction can be effectively empiricised and provides an accurate description of these distributions for hard sphere fluids . these exotic complexities with @xmath2 are not reflected in eq . [ gaussian ] . tiny features like that were noticed , however , in the initial simulation studies of these probability models@xcite . additionally , we anticipate discussion below by noting that proximity to a low pressure liquid - vapor transition point , associated with solvent - solvent attractive interactions and potential dewetting of hard surfaces , is expected to _ increase _ @xmath2@xcite . a more workman - like investigation of these theories can be based upon the potential distribution theorem@xcite @xmath34 the brackets @xmath35 indicate the average of the thermal motion of a distinguished a solute and the solvent under the condition of no interactions between these subsystems ; the latter restriction is conveyed by the subscript ` 0 . ' distributions @xmath13 should be helpful as importance functions . it would be natural to use this estimate to revise the calculation of all the probabilities @xmath4 . but we have seen a case , fig . 2 , where the distinction between n=0 and n@xmath331 is most interesting . in addition , this quantity averaged here eq . [ widom ] takes the values zero ( 0 ) if n@xmath331 and one ( 1 ) for n=0 . thus we consider the importance function @xmath36 the standard importance sampling ideas@xcite then produce @xmath37 the sampling distribution is the boltzmann weight in eq . [ widom ] multiplicatively augmented by the configurational function @xmath38 and corresponds to a finite probability step @xmath39 as the first solvent molecule enters the observation volume . typically , this will lead to a diminished occupancy of the observation volume . after some rearrangement , eq . [ important ] is @xmath40 here @xmath41 is the probability of the observation volume being empty with the reweighted sampling @xmath42 these formulae could be used directly with simulation calculations . the best available approximate @xmath2@xcite could be used as @xmath43 in order to achieve higher accuracy ; that would be interesting but not easy because achieving n@xmath44 n=0 transitions requires rare collective processes . on the other hand , n=0@xmath45n@xmath331 transitions will have a low acceptance probability . but our argument here is directed toward understanding physical features left out of simple models such as the quasi - chemical model of eq . [ eq : pf ] . the choice here of w in eq . [ weight ] is transparently directed towards discussion of a ` two - state ' picture of the hydration . with that goal , the conceptual perspective is the more interesting one . this is a discrete example of a procedure common in density functional arguments . local particle occupancies are altered by a reweighting . just as with @xmath2 , @xmath41 can be studied with a mayer - montroll series and moment modeling@xcite . the moments involved now would be obtained from study of the designed non - uniform system . the average on the right - side of eq . [ pi0 ] is a functional of the density induced by the reweighting . for example , if the reweighting can serve to nucleate a bubble because of proximity of the thermodynamic state to a liquid - vapor transition , then , physically viewed , @xmath41 is expected to be composed of two important cases : ( a ) ` vapor ' with a depletion region surrounding the observation volume ; this gives contribution one ( 1 ) to @xmath41 for these cases and ( b ) ` liquid ; ' typically these cases will contribute zero ( 0 ) to @xmath41 . but occasional configurations , roughly with frequency @xmath43 , will give @xmath46 . thus as a rough estimate , we expect @xmath47 where @xmath48 is the free energy for formation of a bubble from the liquid corresponding to boundary conditions n=0 on the observation volume . that free energy might be approximated by a combination of van der waals theories and molecular theories appropriate for the vapor phase@xcite . let s consider a one phase , dense liquid thermodynamic state , not far from coexistance with a vapor phase so that 1@xmath49 . with these estimates , eqs . [ correct ] and [ engest ] evaluate to @xmath50 the insertion probability is the probability of bubble formation , surely the only simple guess , and this estimated change raises the value @xmath51 . on the basis of the observations above , we can construct the following picture@xcite by considering how these theories would work for an atomic size hard sphere solute in a simple van der waals fluid system . consider packing effects first , then subsequently the effects of attractive interactions . for dense liquid cases with full - blown packing difficulties , models such as eq . [ gaussian ] or [ cluster - var ] overestimate @xmath2 because those models are nt accurate for packing problems in the dense fluid regime . next , consider attractive interactions and the possibility of dewetting . those effects raise @xmath2 . models such as eq . [ gaussian ] do not reflect these phenomena . but these two errors can compensate , so eq . [ gaussian ] can be empirically accurate for atomic solutes despite the naivit . this is another rationalization of the astonishing , fortuitous accuracy of the two moment model and of the pratt - chandler theory . while absorbing this argument , there are two additional points that may be noted . the first point is that in discussing errors in treating packing effects , we have been concerned about errors of the same type as those in the percus - yevick theory for the hard sphere fluid . but the percus - yevick theory of the hard sphere fluid might be considered _ the _ most successful theory of a liquid , `` gloriously accurate , considering its simplicity''@xcite . so this discussion is bringing a high - sensitivity view to this problem . this is necessary because of the importance and high interest in these problems . the second point for note is that ` attractive interactions ' in this argument involve solvent - solvent interactions , _ not _ solute - solvent attractive interactions . part of the subtlety of these discussions is that the approach that offers models such as eq . [ gaussian ] is sufficiently empirical that a unique identification of the source of a particular inaccuracy is nontrivial . the most astonishing result of the new theory eq . [ gaussian ] is its explanation of the hydrophobic temperature dependence known as ` entropy convergence ' @xcite and those temperature dependences are discussed here . the solubilities of simple gases in water have some interesting complexities@xcite . many simple gases have a solubility minimum in water at moderate temperatures and pressures . since the solubility is governed by @xmath52 , the temperature variation of the solubility at a fixed pressure requests information on @xmath53 with @xmath54 the partial molar enthalpy change upon dissolution of species a and we considering the low concentration limit here . thus , a solubility minimum leads us to anticipate a temperature of zero enthalpy change for the dissolution where @xmath55 plotted as a function of t has a maximum . at a higher temperature the dissolution of many simple gases shows approximately zero partial molar entropy change : @xmath56 @xmath57 plotted as a function of @xmath58 has a maximum . more puzzling is the fact that this temperature of zero entropy change is common to a number of different gases . this phenomenon is referred to as ` entropy convergence ' because the entropies of hydration of different solutes converge to approximately zero at a common temperature@xcite . the puzzle `` why ? '' was first answered on a molecular level in ref . @xcite on the basis of the model eq [ gaussian ] ; see also@xcite . establishing these two temperature behaviors should go a long way toward establishing the temperature variations of hydrophobic effects throughout an extended range relevant to biomolecular structure . if we agree to be guided by an estimate of @xmath4 based upon a continuous normal distribution@xcite then evaluation of the lagrange multipliers of eq . [ gaussian ] is not a problem and @xmath59 \right\ } \label{eq : muex.a } \\ & = & { 1\over 2}\left\ { { \left(\rho v\right ) ^2 \over \langle \delta n^2 \rangle_0 } + \ln[2\pi \langle \delta n^2 \rangle_0 ] \right\ } \label{eq : muex.b } \end{aligned}\ ] ] with @xmath60 the volume of the aw excluded volume , expected to be weakly temperature dependent . the surprise is that @xmath61 varies only slightly with temperature over the interesting temperature range . this is suggestive of the data shown in fig . 1 . furthermore the second term of eq . [ eq : muex.b ] is smaller than the first . therefore the plot of @xmath57 as a function of @xmath58 experiences a maximum because the combination @xmath62 has a maximum as @xmath63 decreases with increasing temperature along the coexistence curve . to the extent that the rightmost term of eq . [ eq : muex.b ] can be neglected and @xmath64 is independent of temperature , then entropy convergence will occur and the temperature at entropy convergence will be the same for all hydrophobic solutes . this development applies to model hard core solutes and the convergence temperature does appear to shift slowly but systematically to lower temperatures as the volume of the solute increases . but it was disturbingly noted nearly forty years ago that the success of the scaled particle model in evaluating hydration entropies `` @xmath8 suggests an almost thermodynamic independence of molecular structure''@xcite . in the entropy convergence phenomena , we see that this almost thermodynamic independence of molecular structure is a feature of the data@xcite and that the current theory gives a simple molecular explanation that resolves that puzzle . the lower temperature iso - enthalpy solubility minimum is expected to be tied to a different aspect of the solution - water interactions , the van der waals attractive interactions . following a wca view , these effects should be reasonably described by first order perturbation theory so as a qualitative model we have@xcite @xmath65 with fitting parameters a , b , and c. this equation does indeed have the correct qualitative behaviors@xcite . if this eq . [ schemat ] is used as a fitting model and the parameters are unrestricted , it is essentially perfect . if the parameters are constrained by physical expectations for the temperature independent fitted parameters are v , @xmath66 , and a , then this model is only qualitatively and crudely successful in describing experimental solubilities . several of these considerations have been reexamined recently with results consistent with this picture@xcite . although these temperature behaviors were not always so clearly recognized as this , there remains specific solubility issues that are nt resolved including at the simulation level . an interesting case was provided by the important simulation calculations of swope and andersen@xcite on solubility of inert gas atoms in water . with regard to the lennard - jones solute water ( oxygen ) interaction models , they concluded : `` for the potentials used in the present simulations , it is not possible to fit the value , slope , and curvature for helium and neon without choosing what we believe to be unreasonably large values of @xmath67 . we can , however , obtain fits to the data for argon and krypton with reasonable values of the diameters . '' simulation calculations for such cases have been pursued several times since then ; those activities up to 1998 are summarized by arthur and haymet@xcite and the latter effort also concludes with some ambiguity about the case of the he solute . it is also important to emphasize that this model is used here only over a limited temperature range and at low pressure . lin and wood@xcite used molecular dynamics to model the thermodynamic properties of small hydrocarbons in water over a wide range of temperature and pressure and errington , _ et al._@xcite studied the phase equilibria of water - methane and water - ethane systems of over wide ranges of temperature and pressure using monte carlo techniques . in recent years , efforts to measure directly the structure of water surrounding simple hydrophobic solutes have produced results that should be of quantitative relevance to the theories discussed here@xcite . a more quantitative consideration is warranted but the initial impression is that these results are in good agreement with the calculations that have been done . these data give the weight of evidence to important basic conclusions also . one such conclusion is that this structuring of water appears to be independent of variations of the pressure to 700 bar ( 70 mpa)@xcite . this may be important to the current issue of pressure denaturation of soluble proteins as is discussed below . but investigation in a higher pressure range would be necessary for that purpose@xcite . another important conclusion follows from the direct comparison of the radial distribution of oxygen atoms surrounding kr in liquid aqueous solution and in a solid clathrate phase . those radial distributions are qualitatively different in the two different phases . this is important because a ` clathrate ' picture of hydration structure of nonpolar solutes in liquid water is a common view of hydrophobic hydration that has not been of quantitative relevance ; it has been a ` pictorial theory'@xcite . in contrast , several theoretical calculations that have had quantitative value assume roughly the antithesis of ` clathrate , ' that the conditional density of water surrounding of a non - spherical nonpolar solute can be built - up by superposition of proximal radial information@xcite . the ` clathrate ' language is widely used , hardly explicitly justified , and leads to misunderstandings . a number of studies have explicitly considered the issue of how valid is the ` clathrate ' description@xcite . the conclusion seems to be that if you look for clathrate - style hydration structures you probably see them but if you ask whether they are necessary for a correct quantitative understanding , the answer is ` no . ' ` clathrate ' is in the eye of the beholde . a reasonable recommendation is that when ` clathrate ' is used as a descriptor in these liquid solutions , it should be explicitly defined and justified . attempts to formulate quantitative theories on the basis of chemical models of these hydration shells are known but ill - developed@xcite . the theories discussed above are straight - forwardly applicable to non - spherical solutes . for a solute composed of two atoms with varying interatomic separation , the comparison @xmath68 leads to the classic issue of the ` potential of mean force ' ( pmf ) , an issue of long - standing interest@xcite . the model eq . [ gaussian ] for a simple case was tested against simulation results@xcite and the comparison was close . that theory , including eq . [ eq : muex.b ] , sheds new light on these properties . consider @xmath69 for atomic solutes in contact . when the solute atoms are in van der waals contact , we still anticipate that @xmath70 will be only weakly temperature dependent . further , the volume excluded to the solvent by the pair is less than twice the volume of an atom alone because of the overlap of their excluded regions . thus the dominant contribution to eq . [ pmf ] is negative , stabilizing the contact pair , and that stabilization increases with temperature below the entropy convergence temperature . [ note that the subtraction eq . [ pmf ] requires some additional thought when the logarithmic term of eq . [ eq : muex.b ] is addressed@xcite . if the subtraction were naively carried - out , that r - independent nonzero difference might imply pathologically long - ranged interactions . a more careful consideration of the statistical approaches satisfactorily resolves that pathology@xcite . this detail shows again that these theories are not naively equivalent to the pratt - chandler theory . ] on the other hand , when the atomic solutes are separated enough that a water molecule may fit between them , the volume excluded to the solvent by the pair is more nearly twice the excluded volume of the separated atoms . the theories following eq . [ gaussian ] then are more sensitive to water molecule correlations of longer range because the information @xmath66 depends on those correlations . these theories then produce more subtle effects . non - contact hydrophobic interactions may be , nevertheless , significant because of the larger configurational volume corresponding to those solvent - separated configurations . in addition , as discussed by pratt and chandler@xcite , free energies of these solvent - separated configurations may be more sensitive to details of van der waals attractive interactions than are contact configurations . these views seem to be born out by the available simulation results , although@xcite `` the conclusions drawn from previous simulation calculations have been very contradictory . '' substantial stability for contact hydrophobic pairs is probably the least contradictory of the possible conclusions . the recent preponderance of simulation results indicate that these contact pairs are stabilized by favorable hydration entropies@xcite . this would agree with the view established from the simple model eq . [ eq : muex.b ] but those model temperature variations have been checked mostly along the liquid - vapor coexistence curve . the interesting results of ref . @xcite find substantial temperature variations at fixed water density . it was noted@xcite that the conditions of temperature increase at fixed density strengthen the apparent entropic stabilization of the contact pair . that is also how eq . [ eq : muex.b ] works ; the density decrease serves to moderate the temperature increase and eventually , at the entropy convergence temperature , to dominate it . but the large effects seen by the vienna group@xcite make it unclear that the simple model eq . [ eq : muex.b ] will be accurate for those phenomena . simulation results for the solvent - separated configurations are less clear also . there are entropic and enthalpic temperature effects in opposite directions with small net results@xcite . because of the larger configurational volume for the solute pair in this configuration , these smaller hydration free energies are not negligible and@xcite `` the puzzling finding that the marked hydrophobic behavior of methane - like solutes concluded from the free energy data is not reflected in a similarly clear manner by the second osmotic virial coefficients requires a closer inspection of the underlying phenomena . '' see also @xcite . there is precedent , depending on a variety of additional details , for simulation results to exhibit either hydrophobic clustering or not , _ i.e. _ , `` hydrophobic repulsion.''@xcite . the complications suggested for these solvent - separated configurations seem to have lead to other contradictory results . it was suggested long ago@xcite that solute polarizability might change the character of hydrophobic interactions predicted by simple theories . a later simulation calculation that included explicit polarizability@xcite in the water - water interactions also suggested that these more complicated descriptions might qualitatively change the hydration of non - contact atom pairs . further calculations again suggested that polarizability could lead to substantial changes but in a different direction from those seen earlier@xcite ; treatment of long - ranged interactions was noted as a significant issue in these calculations . more recent studies of interaction models that include polarizability , however , have restored an original ` small change ' view for the moment@xcite . the potentials of mean force just discussed are relevant to consideration of the conformational equilibrium of small flexible hydrophobic molecules in water . the first test case for theories has always been the _ trans - gauche _ isomerization of n - butane@xcite . for the case of n - butane , solvent separated possibilities are not available , so the contact hydrophobic interactions are relevant . the population of the more compact _ gauche _ configuration is enhanced by an entropic hydration effect . hummer , _ et al.,_@xcite applied to the model of eq . [ gaussian ] to the case of conformational equilibrium of n - butane in water and found close agreement with the latest simulation results . hummer has effectively adapted the model of eq . [ gaussian ] so that it can be simply applied to other alkanes@xcite . much longer chain molecules that are strictly hydrophobic as less well studied primarily because they would be so unusual as isolated components of aqueous solutions . hydrophilic groups are necessary to solubilize large molecules . perhaps the simplest such soluble molecules would be polyethylene oxide chains which are a specific interest@xcite . but gallicchio , _ et al . , _ @xcite has recently studied the hydration of slightly larger alkanes in additional detail the intense current interest in pressure studies of protein structure is due to the alternative light that this research can shed on protein conformational dynamics . a recent example can be found in @xcite but we are unable to review adequately that body of interesting work here . the complications of the non - contact hydrophobic interactions mentioned above appear to be involved in understanding pressure denaturation of proteins , however . we identify some of that work because views of hydrophobic effects had been paradoxical for these issues and because it gives additional perspective into the theories discussed here . wallqvist reported initial studies of pressure dependence of hydrophobic interactions@xcite . remarkably , atomic hydrophobic solutes in water clustered at low pressure but dispersed at a substantially higher pressure that was nt further quantified in that study . later the rutgers group took an important step@xcite in monte carlo calculations of the effects of pressure on the pmf between lennard - jones model hydrophobic atomic solutes in water . hummer , _ et al._@xcite then developed the theory eq . [ gaussian ] for these pmfs as a function of pressure . that theory suggested that non - contact configurations of hydrophobic pairs become progressively more stable relative to contact pairs and that this might be a feature of pressure denaturation that was known to produce less disrupted structures than does heat denaturation . subsequent molecular dynamics calculations@xcite confirmed this picture of dispersal at higher pressures and the pressure variations of the pmfs : as pressure is increased , these pmfs become more structured , the contact minimum deepens , the desolvation barrier becomes higher , the solvent - separated well becomes better defined , deeper , and it appears to deepen faster than the contact well . this work also observed clustering of hydrophobic atomic solutes at low pressure ( 1 atm ) but dispersal at high pressure ( 8000 atm , 810.6 mpa ) . this work also saw changes in the solute - water(oxygen ) radial distribution that should be observable in experimental studies such as those of ref . but the simulation results are for considerably higher pressures than the experimental work reported . these calculations also considered spherical hydrophobic solutes of a larger size , more comparable with valine , leucine , or iso - leucine side chains . the responses to substantial pressure increases were similar but perhaps slightly more pronounced . a physical view is that as the pressure is increased , water molecules can be jammed between contact hydrophobic pairs ; this evidently results in a more efficient , lower - volume packing , and consequently a negative hydration free energy change with increasing pressure for non - contact configurations . for a hard sphere solute , the rate of increase of the hydration free energy eq [ p0 ] with the distance of closest ao approach , denoted by @xmath71 , produces a particularly interesting quantity @xmath72 this @xmath73 is the conditional density of the solvent water ( oxygen ) at contact with the spherical solute . because of the involvement of @xmath74 this relation describes the compressive force exerted by the solvent on the solute . direct studies of these quantities have shown@xcite that in the range 2.0 @xmath753.0 @xmath76 for liquid water is approximately two - times larger than for n - hexane . water exerts a higher compressive force on the surface of an inert solute than do typical organic liquids so that water squeezes - out hydrophobic solutes @xcite . more pertinent for the present discussion is that the pratt - chandler theory overestimates this compressive force and the original scaled particle model underestimates it@xcite . the revised scaled particle model@xcite lands in the middle and does a better job at describing this compressive force . recent work@xcite has studied these quantities over a much larger range of @xmath71 and confirmed the accuracy of the revised scaled particle model . the reason for the differences between the scaled particle models and the pratt - chandler theory is associated with the known behavior @xmath77 for large @xmath71 . for the cases of first interest , @xmath781 . since @xmath76 is initially one ( 1 ) and typically increases initially , @xmath76 decreases for large @xmath71 to achieve the small value @xmath79 . in fact , this decreasing behavior obtains for @xmath803 , approximately . thus , for hard sphere solutes with @xmath813 the contact density can be small . this low pressure for a dense liquid is due to attractive forces between the solvent molecules . if the conditions are adjusted for liquid - vapor coexistence , then p is also the pressure of the coexisting vapor and @xmath82 would be the density of the vapor under the assumption that it can be treated as ideal . under these conditions we can , therefore , say that a sufficiently large hard sphere solute nucleates a bubble of the vapor . these behaviors are built into the approximate scaled particle models but not into the pratt - chandler theory . these issues had been directly investigated for spherical model solutes moderately larger than canonical for methane@xcite ; weak effects and were found for those cases and convincing models were developed@xcite . this issue has been of particular interest recently because a previous calculation@xcite studied the pmf between modeled stacked plates with exclusively repulsive interactions with water molecules . that work suggested that contact hydrophobic interactions in that case could be dominated by a dewetting event : the last two layers of water molecules intervening between parallel plates evacuated together . the comparable results for more realistically modeled benzene , or toluene , or other small aromatic solute molecule pairs are also interesting but more complicated@xcite . these molecules are slightly smaller than the stacked plates that were studied . in the first place , ` t'-shaped contact pairs are more probable for benzene than a stacked arrangement is . the opposite is true for toluene@xcite . this is also true for the gas - phase potential energy surface though the hydration seems to enhance this distinction@xcite slightly . in the second place , variations in these pmfs@xcite are much smaller than for the modeled stacked plates@xcite . a dewetting transition is not obvious for the calculations with higher molecular realism . it may be the significance of any dewetting would be more obvious near transitional configurations such as the desolvation barrier region that separates contact from solvent - separated configurations . though the hydration of neither of the high probability configurations discussed here seemed@xcite remarkable in this way , the variation of the free energy in the desolvation barrier region might be unusual ; this deserves further checking . how these complications are affected by the more complicated environment of an amino acid side chain , _ e.g. , _ phenyl alanine , in a hydrated protein is not known ; the peptide backbone is , of course , highly polar . the hydrogen bonding possibilities of tyrosine or tryptophan side chains complicate things yet again . an interesting study of pairing of tryptophan - histidene side chains @xcite suggested that hydration of these side chains results in stacked pairing near protein surfaces but ` t'-contacts in protein interiors . [ continuum dielectric models did not provide a rationalization of that observed tendency@xcite . ] the variety of the results obtained suggested@xcite `` @xmath8 the importance of the atomic details of the solvent in determining the free energy for the solute - solute interactions . '' the development of the theory corresponding to the stacked plates data was initiated by lum , chandler , and weeks ; see fig . 1 there@xcite . subsequently@xcite , a focus has been the study of how the entropy dominated hydration free energies discussed above for inert gas solubilities change to the surface tension dominated behavior expected for ideal mesoscopic hydrophobic species ; see also@xcite . that behavior was explicitly built into the revised scaled particle model for hard sphere solutes decades ago@xcite ; that model is known to be accurate for water@xcite and for a simple liquid@xcite . a fundamental niche for that theoretical work@xcite is the development of a molecular description of the interface formation mechanism built into the revised scaled particle model at large sizes@xcite . how these theoretical developments will accommodate heterogeneity of chemistry and structure that is typical of biomaterials , in contrast to the model stacked plates , is not yet established . a nice example of the issue of heterogeneity , absorption of water on activated carbon , was discussed recently by mller and gubbins@xcite . it is unreasonable to imagine that the biophysical applications will be simpler than this . it might be more appropriate at this stage of development to regard that berkeley project as ambitiously directed toward an implicit hydration model@xcite rather than an assertion of specific physical relevance of ` drying ' to biomolecular structure@xcite . these problems require consideration of several distinct issues together . one such issue is the direct contributions of solute - solvent attractive interactions to hydration free energies for a specific structure@xcite . a second issue is the indirect effects of solute - solvent interactions in establishing structures and switching between structures as was initially anticipated@xcite . that switching can be sensitive to details of van der waals attractive interactions@xcite . it is worthwhile attempting to articulate a down - to - earth view of the claims of ref . @xcite specifically . for biomolecules , there likely are uncommon transitional structures and conditions for which localized water occupancies can change abruptly . as these transitional structures become indentified , they will be interesting . considering water - hydrocarbon liquid interfaces , not compromised by hydrophilic contacts , it is likely that these interfacial regions will be looser than adjoining bulk phases and more accomodating to imposition of hydrophobic species@xcite . surfactants probably change that conclusion qualitatively@xcite . this is likely to be relevant to protein hydration and function . most solute configurations , except for a few transitional structures , wo nt require specific acknowledgement of ` drying . ' the claims to ref . @xcite do nt seem to require modification of the discussion above on potentials of the mean forces among primitive hydrophobic species in water that separated contact from non - contact configurations and entropy effects from the rest , and then suggested that the more poorly understood non - contact questions are likely to show the most variability . the specific claims of ref . @xcite and the general issues remain questions for research . this review has adopted a narrow theoretical focus and a direct style with the goal of identifying primitive conclusions that might assist in the next stage of molecular research on these problems . these theory and modeling topics havent been reviewed with this goal recently and a review of the bigger topic of hydrophobic effects would not be feasible in this setting . more comprehensive and formal reviews of these topics are in progress and that must be my excuse for considering such a small subset of the work in this area . nevertheless , some historical perspective is necessary in identifying valuable primitive conclusions . one such conclusion is the rectification of the antique ` pratt - chandler theory'@xcite . this was an unexpected development because the advances reviewed above had bypassed stock integral equation theories . it may have been the stock aspect of the earlier approach @xcite that caused the greatest confusion on this topic . there is no obvious point to doing that type of integral equation approximation again for the more complex solutes to which the theoretical interest has progressed . for the problems addressed , however , this amended pratt - chandler theory is now seen to be a compelling , approximate theory with empirical ingredients . the research noted above on _ theory of interface formation _ and _ importance sampling to correct quasi - chemical models _ emphasize that the treatment of those attractive force effects on the hydration problem by the pratt - chandler theory was less satisfactory than that of the scaled particle models . another primitive conclusion is that the scaled particle models@xcite have been the most valuable theories for primitive hydrophobic effects . this is due to the quantitative focus of those models . the quantitative focus of the scaled particle models permitted more incisive analyses@xcite , in contrast to ` pictorial theories , ' and those analyses have lead to significant advances in understanding of these problems . the connection from scaled particle models , to mayer - montroll series@xcite , the potential distribution theorem@xcite , and the quasi - chemical approach@xcite identifies a promising line for further molecular theoretical progress on these problems . comparing eqs . [ eq : pf ] and [ hsqca ] , the amended pratt - chandler theory is most appropriately viewed as a quasi - chemical theory . the anticipated theoretical progress will treat more thoroughly the effects of changes in temperature , pressure , and composition of the solution , including salt effects , and will treat neglected ` context ' hydrophobicity@xcite in detail . that work will study cold denaturation and chemical denaturation in molecular detail . that work will begin to discriminate hydrophobic effects in the cores of soluble proteins from hydrophobic effects in membranes and micelles . that work will begin to consider hydrophobic effects in nanotechnology with molecular specificity . a natural explanation of thermodynamic signatures of hydrophobic hydration , particularly entropy convergence , emerges from these theoretical advances . how those temperature behaviors are involved in cold denaturation or the stability of thermophilic proteins will be a topic for future research . much has been made of the ` gaussian ' character of results such as fig . the observation@xcite best supporting this view can be explained as a cancellation of approximation errors@xcite ; slight inaccuracies of a percus - yevick ( ` gaussian ' ) approximation are balanced by neglect of incipient interface formation for atomic sized solutes . in a number of other cases where these distributions have been investigated carefully simple parabolic models of results such as fig . 2 are less accurate for thermodynamic properties and not only because of the influence of a second thermodynamic phase nearby . nevertheless , quadratic models provide convenient , reasonable starting points for these analyses . a final conclusion regards the better discrimination of contact and non - contact hydrophobic interactions . the contact hydrophobic interactions seem to express the classic picture of entropy dominance at lower temperatures . the non - contact interactions have more variability and are likely to be involved in more unusual effects such as pressure denaturation where a historical picture of hydrophobicity had been paradoxical . the ` theoretical collaboration at los alamos ' mentioned in the introduction has included g. hummer ( nih ) , a. e. garca ( lanl ) , s. garde ( rensselaer polytechnic institute ) , m. a. gomez ( vassar college ) , r. a. laviolette ( ineel ) , m. e. paulaitis ( johns hopkins university ) , and a. pohorille ( nasa ames research center ) . i thank those collaborators for their numerous essential contributions that i have discussed in a personal way here . i thank h. s. ashbaugh and m. e. paulaitis for helpful discussions of this review . this work was supported by the us department of energy under contract w-7405-eng-36 and the ldrd program at los alamos . la - ur-01 - 4900 . 99 bibnamefont # 1#1bibfnamefont # 1#1url # 1`#1`urlprefix[2]#2 [ 2][]#2 , , , , . : , , , , . : . _ _ , . , , , , . : . : , , , , . : , , , . : , , , . : , , . in _ _ , edited by , , , , , : , , . , : . in _ _ , edited by , , , , . : , , , . in _ _ , edited by : , vol , pp . . . : . in _ _ , edited by , _ _ , : . , , , , , . : , , , . . : yyy : , , . : , . : , . : , , . : , , . : , . : , , . p , , , . : , . p , . : , . : , , , , . . : , , , , . : , : , , . : . : , , , , . : , , , . : , , , . : , , , , . : , , , . : , , , . : , , , . : , , , . : , , . : , , . : , , , . : , , , , . : , , , . : , , , , . , , . : . : . : . , , . : , , . : , , . , : . : . in _ _ , , . _ _ , , , , . . : , , , . : , , , . : , , , , . . : . in _ _ , edited by and , , : , . . : . in _ _ , edited by , , , : . . : . in _ _ , edited by , , , : , . . : : , , . _ _ , , , , . : , , , . : , , , . : , , , , . : , , . : , , . : . : . : , , . : , , , , . : , , . , , . , : . in _ _ , edited by _ _ , : . . : , , , . : . : . : , , , . : , , , . : , , , . : , , , , , . : , , , , . : . , , . : , : . _ _ , . : . _ _ , , , , : . , , . : , , . : , , . figure 1 : : the isothermal compressibilities @xmath83 along the liquid - vapor coexistence curve of several organic solvents compared to water@xcite in common units . from top to bottom are n - heptane , carbon tetrachloride , benzene , and water . the compressibility is smaller for water than for these organic solvents , is less strongly temperature dependent , and has a minimum near 46@xmath84 c. the critical temperatures of these organic solvents are all substantially less than the critical temperature of liquid water . figure 2 : : distribution @xmath13 for a isodiameter hard sphere solute in a hard sphere fluid at density @xmath85=0.8 and various models . the dots are simulation results@xcite and the spread indicates a 67% confidence interval . the upper dashed curve is the poisson distribution with the required mean @xmath86 . the long - dashed curve next down is the primitive quasi - chemical model , eq . [ cluster - var]@xcite . the solid line is an ` iterated ' quasi - chemical theory that incorporates an empirical correlation correction@xcite and provides a simple accurate description of these quantities for the hard sphere fluid . note that the primitive quasi - chemical approximation is a good description of this distribution for n@xmath331 but significantly overestimates @xmath2 at these densities .

this paper reviews the molecular theory of hydrophobic effects relevant to biomolecular structure and assembly in aqueous solution . recent progress has resulted in simple , validated molecular statistical thermodynamic theories and clarification of confusing theories of decades ago . current work is resolving effects of wider variations of thermodynamic state , _ e.g. _ pressure denaturation of soluble proteins , and more exotic questions such as effects of surface chemistry in treating stability of macromolecular structures in aqueous solution aqueous solutions , biomolecular structure , statistical thermodynamics , quasi - chemical theory , pressure denaturation

the study of the electromagnetic transitions of the decuplet to octet baryons is an important issue for understanding of internal structure of baryons . spin parity selection rules allow for magnetic dipole ( @xmath2 ) , electric quadrapole ( @xmath3 ) and coulomb quadrapole ( @xmath4 ) moments for these decays . these transitions can also give essential information about the wave function of the lowest lying baryons . for example in the @xmath5 transition if initial and final baryons wave functions are spherically symmetric , then the @xmath3 and @xmath4 amplitude must vanish . the results of recent photo production experiments on nucleon at bates @xcite and jefferson lab @xcite shows that these amplitudes are likely to be non zero . this result is an indication that these decays can contain many mysteries . for this reason , these decays must be carefully and completely studied both theoretically and experimentally . the electromagnetic decays of baryons constitute an important class of decays for the determination of fundamental parameters of hadrons . for extracting these parameters , information about the non perturbative region of qcd is required . therefore a reliable non - perturbative approach is needed . among non - perturbative approaches , qcd sum rules @xcite is more predictive in studying properties of hadrons . qcd sum rules is based on the first principles of qcd . in this method , measurable quantities of hadrons in experiments are connected with qcd parameters , where hadrons are represented by corresponding interpolating quark currents taken at large virtualities and correlator of these quark currents is introduced . the main idea is to calculate this correlator with the help of operator product expansion ( ope ) in the framework of qcd in the large euclidean domain and represent this same correlator in terms of hadronic parameters in the other kinematical region . the sum rule for corresponding physical quantity is obtained by matching two representations of the correlator . in the present work , we calculate the baryon decuplet to octet transition form factors in the framework of an alternative approach to the traditional qcd sum rules , i.e. light cone qcd sum rules method . this method is based on the ope near the light cone , which is an expansion over the twist of the operators rather than dimensions as is the case in the traditional qcd sum rules . the non - perturbative dynamics encoded in the light cone wave functions determines the matrix elements of the non - local operators between vacuum and corresponding particle states ( more about his method can be found in @xcite ) . it should be mentions that the electromagnetic baryon decuplet to octet transitions has been investigated in chiral perturbation theory @xcite , ( partially ) quenched chiral perturbation theory @xcite , in lattice simulations of quenched qcd in @xcite , in the large @xmath6 limit of qcd @xcite . in @xcite the transition form factors for @xmath7 decay is calculated within the traditional qcd sum rules using external field method . this @xmath8 decay in qcd light cone qcd sum rules is investigates in @xcite . the plan of this work is as follows . in section 2 , we consider a generic correlator function , which yields light cone sum rules for decuplet to octet baryon transition form factors . then this correlation function is calculated up to twist 4 accuracy for the photon wave functions including first order strange quark mass corrections . in this section we obtain sum rules for form factors of decuplet to octet baryons electromagnetic transition . in section 3 , we present our numerical results and comparison with other approaches is presented . in this section we calculate the baryon decuplet to octet electromagnetic transition form factors . we start our calculation by considering the following correlator function : @xmath9 where @xmath10 and @xmath11 are generic octet and decuplet interpolating quark currents respectively . we will consider the following baryon decuplet to octet electromagnetic transitions @xmath12 first , the phenomenological part of the correlator function can be calculated by inserting a complete set of hadronic states to it . saturating the correlator ( eq . ( [ eq1 ] ) ) by ground state baryons we get : @xmath13 where @xmath14 and @xmath15 denote octet and decuplet baryons with momentum @xmath16 , respectively , @xmath17 and @xmath18 denote the masses of the octet and decuplet baryons respectively , and @xmath19 stand for the contributions of the higher states and the continuum . the matrix elements @xmath20 and @xmath21 are determined as : @xmath22 where @xmath23 and @xmath24 are the residues and @xmath25 is the rarita - schwinger spinor and @xmath26 and @xmath27 are the four spin vectors of the octet and decuplet baryons respectively . the electromagnetic vertex of the decuplet to octet transition can be parameterized in terms of three form factors in the following way @xcite @xmath28 where @xmath29 and @xmath30 is the photon polarization vector . since in our case , photon is real , @xmath31 does not give any contribution to the considered decays and we need to know the values of the form factors @xmath32 and @xmath33 only at @xmath0 . for the experimental analysis , it is desirable to use such form factors which describe physical transition . this would correspond to a definite multipole or helicity transitions in a given reference frame . linear combinations of the the form factors in eq . ( [ eq5 ] ) give magnetic dipole , @xmath34 , electric quadrapole , @xmath35 , and coulomb quadrapole , @xmath36 , form factors . the relations between two set of form factors ( for completeness , we present the relation in general form when @xmath37 . our case corresponds to @xmath0 ) : @xmath38 \frac{m_{\cal o}}{3 ( m_{\cal d}+m_{\cal o } ) } \nonumber \\ g_e & = & \left [ \left(m_{\cal d}^2 - m_{\cal o}^2 + q^2 \right ) \frac{g_1}{m_{\cal d } } + \left ( m_{\cal d}^2-m_{\cal o}^2 \right ) g_2 + 2 q^2 g_3 \right ] \frac{m_{\cal o}}{3 ( m_{\cal d}+m_{\cal o } ) } \nonumber \\ g_c & = & \left [ 2 m_{\cal d } g_1 + \frac12 \left(3 m_{\cal d}^2 + m_{\cal o}^2 - q^2 \right ) g_2 \right . \nonumber \\ & & \left . + \left ( m_{\cal d}^2 - m_{\cal o}^2 + q^2 \right ) g_3 \right ] \frac{2 m_{\cal o}}{3 ( m_{\cal d}+m_{\cal o } ) } \label{eq6}\end{aligned}\ ] ] considering the expression for @xmath35 , one sees that in the case we are interested in , i.e. @xmath0 , @xmath35 is proportional to @xmath39 . as this quantity is very small ( @xmath40 is @xmath41 for the @xmath42 transitions and is @xmath43 for the remaining transitions ) , small uncertainties in @xmath18 or @xmath17 leads to big uncertainties in the predictions for @xmath35 . although the sum rule predictions for the masses of the octet and decuplet baryons agree within errors with the experimental values , the error get amplified in the prediction for @xmath35 . thus it makes a big difference weather one uses the experimental value or the sum rule prediction for the values of @xmath18 and @xmath17 . to give a quantitative idea about this uncertainty , if one considers the @xmath42 transitions , the experimental value of the mass difference of the @xmath44 and the nucleon is @xmath45 , where as the mass prediction from the mass sum rules for the mass of the @xmath44 can be as small as @xmath46 @xcite and the prediction for the mass of the nucleon can be as big as @xmath47 @xcite . thus one sees that , in the extreme cases , if one uses the predictions of the mass sum rules for the masses of the octet and decuplet baryons , even the sign of @xmath35 might change . in our work , we use the experimental values for the masses of the octet and decuplet baryons . but our predictions on @xmath35 should be considered as order of magnitude estimates . in calculations , summation over spins of the rarita - schwinger spin vector is done using the relation : @xmath48 using eqs . ( [ eq2]-[eq5 ] ) and ( [ eq7 ] ) , we see that correlator has numerous tensor structures not all of which are independent . the dependence can be removed by ordering gamma matrices in a specific order . for this purpose , the ordering @xmath49 is chosen . with this ordering , the correlator function becomes : @xmath50 \left\ { -2 g_1 m_{\cal d } - g_2 m_{\cal d } m_{\cal o } + g_2 ( p+q)^2 \right . \nonumber \\ & & + \left . \left [ 2 g_1 + g_2(m_{\cal o}-m_{\cal d } ) \right ] \not\!p + m_{\cal o } g_2 \not\!q - g_2 \not\!q\not\!p \right\ } \gamma_5 \nonumber \\ & & + \left [ q_\mu \not\!\varepsilon - \varepsilon_\mu \not\!q \right ] \left\ { g_1 ( p^2 + m_{\cal d } m_{\cal o } ) - g_1 ( m_{\cal d}+m_{\cal o } ) \not\!p \right\ } \gamma_5 \nonumber \\ & & + 2 g_1 \left [ \not\!\varepsilon ( pq ) - \not\!q ( \varepsilon p ) \right ] q_\mu \gamma_5 \nonumber \\ & & - g_1 \not\!\varepsilon \not\!q \left\ { m + \not\!p \right\ } q_\mu \gamma_5 \nonumber \\ & & \left . \mbox{other structures with $ \gamma_\mu$ at the end or which are proportional to $ ( p+q)_\mu$ } \right ] \nonumber \\ & & \label{eq9}\end{aligned}\ ] ] an essential reason for not considering the structures @xmath51 and the structures which contain a @xmath52 at the end is as follows : a spin-@xmath53 current can have a nonzero overlap with a spin-@xmath54 state : @xmath55 using @xmath56 one can easily obtain that @xmath57 hence , in principle , spin-@xmath54 states can also give contribution to the correlation function . but given the ordering , they contribute only to the structures which contain a @xmath52 at the end or which are proportional to @xmath58 . in other words , spin-@xmath54 particles do not contribute to the structures that we have not omitted . in order to obtain predictions for the values of @xmath32 and @xmath33 , we need to choose two different structures to study . in deciding which structures to study , we have chosen structures which do not get contributions from the contact terms after the borel transformations(for a discussion of the contact terms see @xcite ) . in the exact @xmath59 limit , the contact terms vanish . but since we are interested also in the violations of @xmath60 , the contact terms are in principle non - zero . in order to extract the physical interaction vertex , one has to subtract the contact terms from the correlation function . among the structures in eq . ( [ eq9 ] ) , the structures which receive contributions from the contact terms are @xmath61 and @xmath62 we have studied all the possible pairs of structures . we obtained the best convergence for the pairs @xmath63 and @xmath64 , or @xmath65 and @xmath64 . although the structure @xmath66 receives contributions from the contact terms , the contact terms vanish after the borel transformation . the structures @xmath67 , @xmath68 , and @xmath64 have the coefficients : @xmath69 respectively , where @xmath70 once the sum rules for @xmath71 ( @xmath72 ) are obtained , the sum rules for @xmath73 , ( @xmath74 ) are obtained using the experimental masses of the octet and decuplet baryons through the relations obtained by inverting eqs . ( [ eq6 ] ) and ( [ invert ] ) : in the deep euclidean region where @xmath75 and @xmath76 , the correlation function eq . ( [ eq1 ] ) can be calculated using ope . for this purpose , one needs the explicit forms of the interpolating currents . explicit forms of the interpolating quark currents for the corresponding decuplet members are as follows : @xmath77 \nonumber \\ \eta_\mu^{\sigma^{*+ } } & = & \frac{1}{\sqrt2 } \eta_\mu^{\sigma^{*0}}(d \rightarrow u ) \nonumber \\ \eta_\mu^{\sigma^{*- } } & = & \frac{1}{\sqrt2 } \eta_\mu^{\sigma^{*0}}(u \rightarrow d ) \nonumber \\ \eta_\mu^{\delta^{*+ } } & = & \eta_\mu^{\sigma^{*+}}(s \rightarrow d ) \nonumber \\ \eta_\mu^{\delta^{*0 } } & = & \eta_\mu^{\sigma^{*-}}(s \rightarrow u ) \nonumber \\ \eta_\mu^{\xi^{*0 } } & = & \eta_\mu^{\delta^{0}}(d \rightarrow s ) \nonumber \\ \eta_\mu^{\xi^{*- } } & = & \eta_\mu^{\xi^{*0}}(u \rightarrow d)\end{aligned}\ ] ] it is well known that the choice of the interpolating currents for the octet baryons is not unique . one can define two different currents with the quantum numbers of the octet baryons . the most general current is a linear combination of these two currents . in our studies we chose : @xmath78 \nonumber \\ \eta^{\sigma^+ } & = & \frac{1}{\sqrt2 } \eta^{\sigma^0}(d \rightarrow u ) \nonumber \\ \eta^{\sigma^- } & = & \frac{1}{\sqrt2 } \eta^{\sigma^0}(u \rightarrow d ) \nonumber \\ \eta^p & = & \eta^{\sigma^+}(s \rightarrow d ) \nonumber \\ \eta^n & = & \eta^{\sigma^-}(s \rightarrow u ) \nonumber \\ \eta^{\xi^0 } & = & \eta^{n}(d \rightarrow s ) \nonumber \\ \eta^{\xi^- } & = & \eta^{\xi^0}(u \rightarrow s ) \nonumber \\ \eta^{\lambda } & = & -\sqrt\frac16 \epsilon^{abc } \left [ 2 \left ( u^{at } c d^b \right ) \gamma_5 s^c + 2 t \left ( u^{at } c \gamma_5 d^b \right ) s^c + \left ( u^{at } c s^b \right ) \gamma_5 d^c \right . \nonumber \\ & + & t\left . \left ( u^{at } c \gamma_5 s^b \right ) d^c + \left ( s^{at } c d^b \right ) \gamma_5 u^c + t \left ( s^{at } c \gamma_5 d^b \right ) u^c \right ] \label{eq3}\end{aligned}\ ] ] where @xmath79 is an arbitrary parameter . the ioffe current , generally used in the literature to study the properties of the octet baryons , corresponds to the choice @xmath80 for this parameter . the current used in @xcite corresponds to the limit @xmath81 . the physical quantities should be independent of the value of @xmath79 . in our analysis , a region for the values of @xmath79 is found requiring that the prediction should be independent of the value of @xmath79 . the precise normalization of the octet and decuplet baryons are chosen such that in the @xmath59 limit , the mass sum rules are the same within a multiplet . note that , all the currents except the current of @xmath82 can be obtained from the currents of @xmath83 and @xmath84 by simple substitutions . hence , in the following we will give only the expressions for the @xmath85 . the expressions for the other decays can be obtained using the following relationships : @xmath86 recently , it has been shown in @xcite that it is also possible to obtain the @xmath82 current from that of the @xmath83 current by substitutions . for this purpose , note that @xmath87 and hence @xmath88 the correlator function receives three different types of contributions : perturbative contributions , non - perturbative contributions where photon is emitted from the freely propagating quark , i.e. at short distances , and non - perturbative contributions where the photon is emitted at long distances . in order to calculate the contribution of the terms which come from the long distance emission of the photon , the correlation function is expanded near to the light cone @xmath89.the expansion involves matrix elements of the nonlocal operators between vacuum and the one photon states , which are expressed in terms of photon wave functions with increasing twist . in other words all long distance effects are encoded in the matrix elements of the form @xmath90 . for the propagators of the quarks , we have used the following light quark propagator expanded up to linear order in the quark mass : @xmath91\end{aligned}\ ] ] where @xmath82 is the energy cut off separating perturbative and non perturbative regimes . the matrix elements @xmath90 can be expanded on the light cone in terms of photon wave functions ( in these expansions , we neglect the quark mass corrections ) @xcite : @xmath92 \int_0 ^ 1 du e^{i \bar u q x } h_\gamma(u ) \nonumber \\ & & \langle \gamma(q ) \vert \bar q(x ) \gamma_\mu q(0 ) \vert 0 \rangle = e_q f_{3 \gamma } \left(\varepsilon_\mu - q_\mu \frac{\varepsilon x}{q x } \right ) \int_0 ^ 1 du e^{i \bar u q x } \psi^v(u ) \nonumber \\ & & \langle \gamma(q ) \vert \bar q(x ) \gamma_\mu \gamma_5 q(0 ) \vert 0 \rangle = - \frac{1}{4 } e_q f_{3 \gamma } \epsilon_{\mu \nu \alpha \beta } \varepsilon^\nu q^\alpha x^\beta \int_0 ^ 1 du e^{i \bar u q x } \psi^a(u ) \nonumber \\ & & \langle \gamma(q ) | \bar q(x ) g_s g_{\mu \nu } ( v x ) q(0 ) \vert 0 \rangle = -i e_q \qq \left(\varepsilon_\mu q_\nu - \varepsilon_\nu q_\mu \right ) \int { \cal d}\alpha_i e^{i ( \alpha_{\bar q } + v \alpha_g ) q x } { \cal s}(\alpha_i ) \nonumber \\ & & \langle \gamma(q ) | \bar q(x ) g_s \tilde g_{\mu \nu } i \gamma_5 ( v x ) q(0 ) \vert 0 \rangle = -i e_q \qq \left(\varepsilon_\mu q_\nu - \varepsilon_\nu q_\mu \right ) \int { \cal d}\alpha_i e^{i ( \alpha_{\bar q } + v \alpha_g ) q x } \tilde { \cal s}(\alpha_i ) \nonumber \\ & & \langle \gamma(q ) \vert \bar q(x ) g_s \tilde g_{\mu \nu}(v x ) \gamma_\alpha \gamma_5 q(0 ) \vert 0 \rangle = e_q f_{3 \gamma } q_\alpha ( \varepsilon_\mu q_\nu - \varepsilon_\nu q_\mu ) \int { \cal d}\alpha_i e^{i ( \alpha_{\bar q } + v \alpha_g ) q x } { \cal a}(\alpha_i ) \nonumber \\ & & \langle \gamma(q ) \vert \bar q(x ) g_s g_{\mu \nu}(v x ) i \gamma_\alpha q(0 ) \vert 0 \rangle = e_q f_{3 \gamma } q_\alpha ( \varepsilon_\mu q_\nu - \varepsilon_\nu q_\mu ) \int { \cal d}\alpha_i e^{i ( \alpha_{\bar q } + v \alpha_g ) q x } { \cal v}(\alpha_i ) \nonumber \\ & & \langle \gamma(q ) \vert \bar q(x ) \sigma_{\alpha \beta } g_s g_{\mu \nu}(v x ) q(0 ) \vert 0 \rangle = e_q \qq \left\ { \left[\left(\varepsilon_\mu - q_\mu \frac{\varepsilon x}{q x}\right)\left(g_{\alpha \nu } - \frac{1}{qx } ( q_\alpha x_\nu + q_\nu x_\alpha)\right ) \right . \right . q_\beta \nonumber \\ & & - \left(\varepsilon_\mu - q_\mu \frac{\varepsilon x}{q x}\right)\left(g_{\beta \nu } - \frac{1}{qx } ( q_\beta x_\nu + q_\nu x_\beta)\right ) q_\alpha \nonumber \\ & & - \left(\varepsilon_\nu - q_\nu \frac{\varepsilon x}{q x}\right)\left(g_{\alpha \mu } - \frac{1}{qx } ( q_\alpha x_\mu + q_\mu x_\alpha)\right ) q_\beta \nonumber \\ & & + \left . \left(\varepsilon_\nu - q_\nu \frac{\varepsilon x}{q.x}\right)\left ( g_{\beta \mu } - \frac{1}{qx } ( q_\beta x_\mu + q_\mu x_\beta)\right ) q_\alpha \right ] \int { \cal d}\alpha_i e^{i ( \alpha_{\bar q } + v \alpha_g ) qx } { \cal t}_1(\alpha_i ) \nonumber \\ & & + \left[\left(\varepsilon_\alpha - q_\alpha \frac{\varepsilon x}{qx}\right ) \left(g_{\mu \beta } - \frac{1}{qx}(q_\mu x_\beta + q_\beta x_\mu)\right ) \right . q_\nu \nonumber \\ & & - \left(\varepsilon_\alpha - q_\alpha \frac{\varepsilon x}{qx}\right ) \left(g_{\nu \beta } - \frac{1}{qx}(q_\nu x_\beta + q_\beta x_\nu)\right ) q_\mu \nonumber \\ & & - \left(\varepsilon_\beta - q_\beta \frac{\varepsilon x}{qx}\right ) \left(g_{\mu \alpha } - \frac{1}{qx}(q_\mu x_\alpha + q_\alpha x_\mu)\right ) q_\nu \nonumber \\ & & + \left . \left(\varepsilon_\beta - q_\beta \frac{\varepsilon x}{qx}\right ) \left(g_{\nu \alpha } - \frac{1}{qx}(q_\nu x_\alpha + q_\alpha x_\nu ) \right ) q_\mu \right ] \int { \cal d } \alpha_i e^{i ( \alpha_{\bar q } + v \alpha_g ) qx } { \cal t}_2(\alpha_i ) \nonumber \\ & & + \frac{1}{qx } ( q_\mu x_\nu - q_\nu x_\mu ) ( \varepsilon_\alpha q_\beta - \varepsilon_\beta q_\alpha ) \int { \cal d } \alpha_i e^{i ( \alpha_{\bar q } + v \alpha_g ) qx } { \cal t}_3(\alpha_i ) \nonumber \\ & & + \left . \frac{1}{qx } ( q_\alpha x_\beta - q_\beta x_\alpha ) ( \varepsilon_\mu q_\nu - \varepsilon_\nu q_\mu ) \int { \cal d } \alpha_i e^{i ( \alpha_{\bar q } + v \alpha_g ) qx } { \cal t}_4(\alpha_i ) \right\}\end{aligned}\ ] ] where @xmath93 is the magnetic susceptibility of the quarks , @xmath94 is the leading twist 2 , @xmath95 , @xmath96 , @xmath97 and @xmath98 are the twist 3 and @xmath99 , @xmath100 , @xmath101 ( @xmath102 ) are the twist 4 photon distribution amplitudes . with all these input , after tedious calculations one obtains the expression of the correlation function in eq . ( [ eq1 ] ) in terms of qcd parameters . the two expressions of the correlation function , in two different kinematical regions are then matched using dispersion relation . the contributions of the higher states and the continuum are modeled using the quark - hadron duality . finally , the sum rules are obtained after applying borel transformations to the results in order both to suppress the contributions of the higher states and the continuum and to eliminate the polynomials on @xmath103 or @xmath104 which appear in dispersion relations . our final results for the coefficients defined in eq . ( [ sigma ] ) are : @xmath105 m^4 \chi \varphi_\gamma ( u_0 ) \nonumber \\ & & + \frac{1}{192 \pi^2 } ( 1 - t ) \left ( e_u + e_d - 2 e_s \right ) f_{3 \gamma } \left [ 6 \psi^a ( u_0 ) - \bar u_0 { \psi^a } ' ( u_0 ) + 4 \bar u_0 \psi^v ( u_0 ) \right ] m^4 \nonumber \\ & & - \frac{m_0 ^ 2}{108 m^2 } \bar u_0 \left [ e_u \uu \left[2 \ss ( 5 + 2 t ) - \dd ( 5 - t ) \right ] \right . \nonumber \\ & & \left . + e_d \dd \left[2 \ss ( 5 + 2 t ) - \uu ( 5 - t ) \right ] - 5 e_s \ss ( \uu + \dd ) \right ] \tilde i_2 ( h_\gamma ) \nonumber \\ & & - \frac{m_0 ^ 2}{432 m^2 } ( 1 - t ) \bar u_0 \left ( e_u ( m_d \dd + m_s \ss ) + e_d ( m_u \uu + m_s \ss ) \right . \nonumber \\ & & \left . - 2 e_s ( m_u \uu + m_d \dd ) \right ) f_{3 \gamma } \left(4 \psi^v(u_0 ) - { \psi^a}'(u_0 ) \right ) \nonumber \\ & & - \frac{m_0 ^ 2}{216 m^2 } ( 1+t ) \left [ e_u ( \dd m_s + \ss m_d ) + e_d ( \ss m_u + \uu m_s ) \right . \nonumber \\ & & \left . - 2 e_s ( \dd m_u + \uu m_d ) \right ] f_{3 \gamma } \psi^a(u_0 ) \nonumber \\ & & + \frac{1}{8 \pi^2 } \left [ e_u m_u \left ( \ss ( 1+t ) + 2 \dd t \right ) + e_d m_d \left ( \ss ( 1+t ) + 2 \uu t \right ) \right . \nonumber \\ & & \left . - e_s m_s \left(\uu + \dd \right ) ( 1 + 3 t ) \right ] m^2 \left ( \gamma_e - \ln \frac{m^2}{\lambda^2 } \right ) \nonumber \\ & & - \frac{m_0 ^ 2}{144 \pi^2 } \left [ e_u \left [ \ss ( 1+t ) ( m_d + 5 m_u ) + \dd ( m_s ( 1+t ) + 10 m_u t ) \right ] \right . \nonumber \\ & & + e_d \left [ \ss ( 1+t ) ( m_u + 5 m_d ) + \uu ( m_s ( 1+t ) + 10 m_d t ) \right ] \nonumber \\ & & \left . - e_s \left [ 2 ( 1+t ) ( m_u \dd + m_d \uu ) + 5 ( 1 + 3 t ) m_s ( \dd + \uu ) \right ] \right ] \left ( \gamma_e - \ln \frac{m^2}{\lambda^2 } \right ) \nonumber \\ & & -\frac{m_s}{24 \pi^2 } ( e_u \uu + e_d \dd ) i_1 \left ( ( 1+t ) ( { \cal t}_1+{\cal t}_3 ) - ( 3 + t ) ( { \cal t}_2 - \tilde{\cal s } ) - ( 1 + 3 t ) ( { \cal t}_4+{\cal s}),1 \right ) \times \nonumber \\ & & \times m^2 \left ( \gamma_e - \ln \frac{m^2}{\lambda^2 } \right ) \nonumber \\ & & + e_s \frac{\ss}{24 \pi^2 } ( m_u + m_d ) i_1 \left ( ( 3+t){\cal t}_1 -(1+t ) ( { \cal t}_2 + { \cal t}_4 + { \cal s } -\tilde { \cal s } ) + ( 1 + 3t){\cal t}_3,1\right ) \times \nonumber \\ & & \times m^2 \left ( \gamma_e - \ln \frac{m^2}{\lambda^2 } \right ) \nonumber \\ & & - \frac{1}{12 \pi^2 } ( e_u \uu m_d + e_d \dd m_u ) i_1 \left ( { \cal t}_1 + { \cal t}_2 - \tilde { \cal s } + t ( { \cal t}_3 + { \cal t}_4 + { \cal s}),1\right ) m^2 \left ( \gamma_e - \ln \frac{m^2}{\lambda^2 } \right ) \nonumber \\ & & + e_u \frac{1}{16 \pi^2 } \left [ \dd \left(m_d ( -1+t ) + 4 ( m_u - m_s ) t \right ) + \ss \left(m_s ( -1+t ) + 2 m_u ( 1+t ) - 4 m_d t \right ) \right ] m^2 \nonumber \\ & & + e_d \frac{1}{16 \pi^2 } \left [ \uu \left(m_u ( -1+t ) + 4 ( m_d - m_s ) t \right ) + \ss \left(m_s ( -1+t ) + 2 m_d ( 1+t ) - 4 m_u t \right ) \right ] m^2 \nonumber \\ & & - e_s \frac{1}{8 \pi^2 } \left [ \uu \left ( m_s ( 1 + 3 t ) - m_u ( 1-t ) - 4 m_d t\right ) + \dd \left ( m_s ( 1 + 3 t ) -m_d ( 1-t ) -4 m_u t \right ) \right ] m^2 \nonumber \\ & & + \frac{1}{6 } \left [ e_u \uu ( \ss ( 1+t ) + 2 \dd t ) + e_d \dd ( \ss ( 1+t ) + 2 t \uu ) \right.\nonumber \\ & & \left . - e_s \ss ( 1 + 3 t ) ( \uu + \dd ) \right ] m^2 \chi \varphi_\gamma(u_0 ) \nonumber \\ & & - \frac{\bar u_0}{16 \pi^2 } \left[e_u \uu ( m_s ( 3+t ) - 2 m_d ) + e_d \dd ( m_s ( 3+t ) -2 m_u ) \right . \nonumber \\ & & \left . - e_s \ss ( 1+t)(m_u+m_d ) \right ] m^2 \tilde i_2(h_\gamma ) \nonumber \\ & & + \frac{1}{32 \pi^2 } \left [ e_u \uu ( m_s ( 1+t ) + 2 m_d t ) + e_d \dd ( m_s ( 1+t ) + 2 m_u t ) \right . \nonumber \\ & & \left . - e_s \ss ( m_u + m_d ) ( 1 + 3 t ) \right ] m^2 { \mathbb a } ( u_0 ) \nonumber \\ & & - e_s \frac{\ss}{24 \pi^2 } ( m_u+m_d ) m^2 \left [ 2 ( -1+t ) i_1 ( { \cal t}_1,1 ) + 2 ( 1+t ) i_1 ( { \cal t}_2,v ) + ( 3 + 5 t ) i_1 ( { \cal t}_4,1 ) \right ] \nonumber \\ & & - \frac{1}{24 \pi^2 } \left [ ( 1+t ) m_s ( e_d \dd + e_u \uu ) - e_s \ss ( m_u+m_d ) ( 1 + 3 t)\right ] m^2 \times \nonumber \\ & & \times \left [ i_1 \left ( { \cal t}_2 + 2 { \cal t}_3,1 \right ) - 2 i_1 \left({\cal t}_3 - { \cal t}_4,v\right ) \right ] \nonumber \\ & & + \frac{1}{12 \pi^2 } \left ( e_d \dd m_u + e_u \uu m_d \right ) m^2 \left [ - 3 t i_1({\cal s},1 ) - i_1 ( \tilde { \cal s},t - 2 v ( 1+t ) ) + ( -1+t ) i_1 ( { \cal t}_1,1 ) \right . \nonumber \\ & & \left . -i_1({\cal t}_2,t+2 v ) - 2 t i_1 ( { \cal t}_3,1-v ) - t i_1 ( { \cal t}_4,1 + 2 v ) \right ] \nonumber \\ & & + \frac{m_s}{24 \pi^2 } \left ( e_d \dd + e_u \uu \right ) m^2 \left [ 2 ( 3+t ) i_1 ( { \cal t}_2,v ) + ( 3 + 7 t ) i_1({\cal t}_4,1 ) \right ] \nonumber \\ & & + \frac{m_s}{24 \pi^2 } \left(e_d \dd + e_u \uu \right ) m^2 \left[(1 + 5 t ) i_1 ( { \cal s},1 ) - ( 1+t ) i_1 ( \tilde { \cal s},1 ) - 4 i_1(\tilde { \cal s},v ) \right ] \nonumber \\ & & + \frac{t}{3 } \left ( \ss ( e_u \dd + e_d \uu ) -2 e_s \uu \dd \right ) \nonumber \\ & & + e_s \frac{\ss}{24 \pi^2 } ( m_u+m_d ) m^2 \left [ ( -1+t ) i_1({\cal s},1 ) + ( 1 + 3 t ) i_1(\tilde { \cal s},1 ) - 4 t i_1 ( \tilde { \cal s},v ) \right ] \nonumber \\ & & + e_u \frac{m_0 ^ 2}{144 \pi^2 } \left [ \ss ( 9 m_d t - 2 m_s ( -1+t ) ) + \dd ( 9 m_s t - 2 m_d ( -1+t ) ) \right ] \nonumber \\ & & + e_d \frac{m_0 ^ 2}{144 \pi^2 } \left [ \ss ( 9 m_u t - 2 m_s ( -1+t ) ) + \uu ( 9 m_s t - 2 m_u ( -1+t ) ) \right ] \nonumber \\ & & - e_s \frac{m_0 ^ 2}{72 \pi^2 } \left [ \dd ( 9 m_u t -2 m_d ( -1+t ) ) + \uu ( 9 m_d t - 2 m_u ( -1+t ) ) \right ] \nonumber \\ & & - \frac{1}{24 } \left [ e_u \uu ( \ss ( 1+t ) + 2 \dd t ) + e_d \dd ( \ss ( 1+t ) + 2 \uu t ) \right . \nonumber \\ & & \left . - e_s \ss ( 1 + 3t)(\uu+\dd ) \right ] \left({\mathbb a}(u_0 ) + \frac{10}{9 } m_0 ^ 2 \chi \varphi_\gamma(u_0 ) \right ) \nonumber \\ & & - \frac{\bar u_0}{6 } \left ( e_u \uu ( 2 \dd - ( 3+t)\ss ) + e_d \dd ( 2 \uu - ( 3+t)\ss ) \right . \nonumber \\ & & \left . + e_s \ss ( 1+t ) ( \uu + \dd ) \right ) \tilde i_2(h_\gamma ) \nonumber \\ & & + \frac{\bar u_0}{48 } ( 1-t ) \left [ e_u ( \dd m_d + \ss m_s ) + e_d ( \uu m_u + \ss m_s ) \right . \nonumber \\ & & \left . -2 e_s ( \uu m_u + \dd m_d ) \right ] f_{3 \gamma } \left ( 4 \psi^v ( \bar u_0 ) - { \psi^a}'(\bar u_0 ) \right ) \nonumber \\ & & + \frac{e_u}{24 } f_{3 \gamma } \left [ \dd ( m_d ( 1-t ) + 4 m_s t ) + \ss ( m_s ( 1-t ) + 4 m_d t ) \right ] \psi^a(u_0 ) \nonumber \\ & & + \frac{e_d}{24 } f_{3 \gamma } \left [ \uu ( m_u ( 1-t ) + 4 m_s t ) + \ss ( m_s ( 1-t ) + 4 m_u t ) \right ] \psi^a(u_0 ) \nonumber \\ & & - \frac{e_s}{12 } f_{3 \gamma } \left[\dd ( m_d(1-t ) + 4 m_u t ) + \uu ( m_u ( 1-t ) + 4 m_d t ) \right ] \psi^a(u_0 ) \nonumber \\ & & + e_s \frac{\ss}{18 } ( \uu + \dd ) \left[2 ( 1+t ) i_1({\cal t}_2,v ) - 2 ( 1 + 2 t ) i_1({\cal t}_2 - { \cal t}_4,1 ) \right . \nonumber \\ & & \left . + ( 1 + 3 t ) \left\{i_1({\cal t}_1 - { \cal t}_3,1 ) + 2 i_1({\cal t}_3 - { \cal t}_4,v ) \right\ } \right ] \nonumber \\ & & + \frac{\ss}{18 } ( e_u \uu + e_d \dd ) \left [ - ( 1+t ) i_1 ( { \cal t}_1 - { \cal t}_3,1 ) \right . \nonumber \\ & & \left . -2 ( 1+t ) i_1 ( { \cal t}_3 - { \cal t}_4,v ) -2 ( 1 + 2t)i_1({\cal t}_4,1 ) \right . \nonumber \\ & & \left . - 2 ( 3+t ) i_1({\cal t}_2,v ) + ( 2+t ) i_1 ( { \cal t}_2,1 ) \right ] \nonumber \\ & & + \frac{e_u+e_d}{9 } \uu \dd \left [ ( -1+t ) i_1({\cal t}_2,1 ) + 2 i_1({\cal t}_2,v ) - t i_1({\cal t}_1 - { \cal t}_3,1 ) -2 t i_1({\cal t}_3 - { \cal t}_4,v ) \right ] \nonumber \\ & & + \frac{t}{9 } \left [ e_u \uu ( 2 \dd - \ss ) + e_d \dd ( 2 \uu - \ss ) - e_s \ss ( \uu+\dd ) \right ] i_1({\cal s},1 ) \nonumber \\ & & + \frac{1}{9 } \left[e_u \uu ( \dd ( 1+t ) - \ss ) + e_d \dd ( \uu ( 1+t ) - \ss ) \right . \nonumber \\ & & \left . -t e_s \ss ( \uu+\dd ) \right ] i_1(\tilde{\cal s},1 - 2v ) \nonumber \\ & & - \frac{f_{3 \gamma}}{36 } ( 1-t ) \left [ e_u ( \dd m_d - \ss m_s ) + e_d ( \uu m_u - \ss m_s ) \right ] i'_1({\cal v},1-v ) \nonumber \\ & & + \frac{1}{36}(1-t ) \left[e_u ( \dd m_d + \ss m_s ) + e_d ( \uu m_s + \ss m_s ) \right . \nonumber \\ & & \left . - 2 e_s ( \dd m_d + \uu m_u ) \right ] f_{3 \gamma } i_1'({\cal a},1-v ) \label{sig6}\end{aligned}\ ] ] @xmath106 m^2 \left ( m^2 \chi \varphi_\gamma(u_0 ) - \frac12 { \mathbb a}(u_0 ) \right ) \nonumber \\ & & + \frac{1}{24 \pi^2 } ( 1-t ) ( e_u + e_d - 2 e_s ) f_{3 \gamma } \left [ i'_1({\cal a } - { \cal v},1-v)+\frac34 \psi^a(u_0 ) + 3 \tilde i_2(\psi_v ) \right ] m^4 \nonumber \\ & & + \frac{1}{4 \pi^2 } ( 1+t ) \left [ e_u m_u ( \dd + \ss ) + e_d m_d ( \uu + \ss ) - 2 e_s m_s ( \uu + \dd ) \right ] \times \nonumber \\ & & \times \left ( \gamma_e - \ln \frac{m^2}{\lambda^2}\right ) \left ( m^2 - \frac{5}{18 } m_0 ^ 2 \right ) \nonumber \\ & & - \frac{m_0 ^ 2}{72 \pi^2 } ( 1+t ) \left [ e_u ( \dd m_s + \ss m_d ) + e_d ( \uu m_s + \ss m_u ) \right . \nonumber \\ & & \left . -2 e_s ( \dd m_u + \uu m_d ) \right ] \left ( \gamma_e - \ln \frac{m^2}{\lambda^2}\right ) \nonumber \\ & & - \frac{1}{12 \pi^2 } ( 1+t ) \left [ e_s \ss ( m_u+m_d ) i_1\left({\cal s } - \tilde { \cal s } - 2 { \cal t}_1 + { \cal t}_2 - 2 { \cal t}_3 + { \cal t}_4,1 \right ) \right . \nonumber \\ & & + ( e_u \uu m_d + e_d \dd m_u ) i_1\left({\cal s } - \tilde { \cal s } + { \cal t}_1 + { \cal t}_2 + { \cal t}_3 + { \cal t}_4,1 \right ) \nonumber \\ & & \left . - m_s ( e_d \dd + e_u \uu ) i_1\left(2{\cal s } - 2\tilde { \cal s } - { \cal t}_1 + 2{\cal t}_2 - { \cal t}_3 + 2{\cal t}_4,1 \right ) \right ] m^2 \left ( \gamma_e - \ln \frac{m^2}{\lambda^2}\right ) \nonumber \\ & & - \frac{m_0 ^ 2}{3 m^2 } \bar u_0 \left(e_u \dd \ss + e_d \uu \ss - 2 e_s \uu \dd \right ) \nonumber \\ & & + \frac{m_0 ^ 2}{216 m^2 } ( 1+t ) \left[e_u ( \dd m_s + \ss m_d ) + e_d ( \uu m_s + \ss m_u ) \right . \nonumber \\ & & \left . -2 e_s ( \dd m_u + \uu m_d ) \right ] f_{3 \gamma } \left ( 4 \tilde i_2(\psi^v ) - \psi^a(u_0 ) \right ) \nonumber \\ & & + \frac{1}{3}(1+t ) \left [ e_u \uu ( \dd + \ss ) + e_d \dd ( \uu + \ss ) - 2 e_s \ss ( \uu + \dd ) \right ] m^2 \chi \varphi_\gamma(u_0 ) \nonumber \\ & & - \frac{1}{4 \pi^2 } \left [ e_u \uu ( 2 m_d + m_s(1+t ) ) + e_d \dd ( 2 m_u + m_s ( 1+t ) ) \right . \nonumber \\ & & \left . - e_s \ss ( m_u + m_d)(3+t ) \right ] m^2 \tilde{\tilde i}_2(h_\gamma ) \nonumber \\ & & + \frac{u_0}{4 \pi^2 } ( 1+t ) \left[\dd ( 2 e_s + e_u)(m_u - m_s ) + \uu ( 2 e_s + e_d)(m_d - m_s ) \right . \nonumber \\ & & \left . + \ss ( e_u - e_d)(m_u - m_d ) \right ] m^2 \nonumber \\ & & - \frac{\bar u_0}{4 \pi^2 } t \left[m_s ( e_u \dd + e_d \uu ) -2 e_s ( m_u \dd + m_d \uu ) + e_s m_s ( \uu+\dd)\right ] m^2 \nonumber \\ & & - \frac{\bar u_0}{8 \pi^2 } ( 1-t ) \left [ e_u ( m_s \ss+m_d \dd ) + e_d ( m_s \ss+m_u \uu)- 2 e_s ( m_u \uu + m_d \dd ) \right ] m^2 \nonumber \\ & & + \frac{\bar u_0}{4 \pi^2 } \left[t e_u \ss ( m_u - m_d ) + t e_d \ss ( m_d - m_u ) \right . \nonumber \\ & & \left . + ( 3+t ) ( e_u \dd m_u + e_d \uu m_d - e_s m_s ( \uu+\dd ) ) \right ] m^2 \nonumber \\ & & + \frac{m_s}{12 \pi^2}(e_u \uu + e_d \dd ) \left [ i_1 ( { \cal s}- \tilde { \cal s}+ { \cal t}_2+{\cal t}_4,1 + 3 t + 2 v ) -2 ( 1+t ) i_1 ( { \cal t}_3,1-v ) \right ] m^2 \nonumber \\ & & + \frac{1}{12 \pi^2 } ( e_u \uu m_d + e_d \dd m_u ) \left [ ( 1 - 3 t ) i_1 ( { \cal s}+{\cal t}_2,1 ) -4 i_1({\cal s}+{\cal t}_2,v ) \right . \nonumber \\ & & \left . + ( 1+t ) i_1 ( \tilde { \cal s}-{\cal t}_4,1 + 2v ) -2(1+t)i_1({\cal t}_3,1-v ) \right ] m^2 \nonumber \\ & & - e_s \frac{\ss}{6 \pi^2 } ( m_u + m_d ) i_1({\cal s}-t \tilde { \cal s}+ { \cal t}_2 - 2 ( 1+t ) { \cal t}_3 + t { \cal t}_4,1-v ) m^2 \nonumber \\ & & + \frac{1}{3}(1+t ) ( e_u \dd \ss + e_d \uu \ss - 2 e_s \uu \dd ) \nonumber \\ & & + \frac{m_0 ^ 2}{16 \pi^2 } u_0 ( 1+t ) \left [ e_u ( \dd m_s + \ss m_d ) + e_d ( \uu m_s + \ss m_u ) - 2 e_s ( \uu m_d + \dd m_u ) \right ] \nonumber \\ & & + \frac{m_0 ^ 2}{72 \pi^2 } \bar u_0 ( 5-t ) ( e_u m_u + e_d m_d ) \ss + \frac{5}{36 \pi^2 } e_s m_0 ^ 2 m_s \bar u_0(\uu + \dd ) \nonumber \\ & & - \frac{m_0 ^ 2}{72 \pi^2 } \bar u_0 ( 15-t ) ( e_u \dd m_u + e_d \uu m_d ) \nonumber \\ & & + \frac{7 m_0 ^ 2}{144 \pi^2 } \bar u_0 ( 1+t ) \left [ e_u ( \dd m_s + \ss m_d ) + e_d ( \uu m_s + \ss m_u ) -2 e_s ( m_u \dd + m_d \uu ) \right ] \nonumber \\ & & + \frac{m_0 ^ 2}{72 \pi^2 } \bar u_0 ( 1-t ) \left [ e_u ( \dd m_d + \ss m_s ) + e_d ( \uu m_u + \ss m_s ) - 2 e_s ( \uu m_u + \dd m_d ) \right ] \nonumber \\ & & - \frac{1}{12 } ( 1+t ) \left[e_u \uu ( \dd + \ss ) + e_d \dd ( \uu + \ss ) -2 e_s \ss ( \uu+\dd ) \right ] \times \nonumber \\ & & \times \left({\mathbb a}(u_0)+ \frac{10}{9}m_0 ^ 2 \chi \varphi_\gamma(u_0 ) \right ) \nonumber \\ & & + \frac{1}{6 } \left [ e_u ( \dd m_s + \ss m_d ) + e_d ( \uu m_s + \ss m_u ) - 2 e_s ( \dd m_u + \uu m_d ) \right ] \times \nonumber \\ & & \times f_{3 \gamma } \left ( t \psi^a(u_0 ) -4 \tilde i_2(\psi^v ) \right ) \nonumber \\ & & + \frac{1-t}{24 } \left[e_u ( \dd m_d + \ss m_s ) + e_d ( \uu m_u + \ss m_s ) - 2 e_s ( \dd m_d + \uu m_u ) \right ] \times \nonumber \\ & & \times f_{3 \gamma } \left ( \psi^a(u_0 ) + 4 \tilde i_2 ( \psi^v ) \right ) \nonumber \\ & & + \frac{1}{3 } \left [ e_u \uu ( 2 \dd + ( 1+t ) \ss ) + e_d \dd ( 2 \uu + ( 1+t ) \ss ) \right . \nonumber \\ & & \left . - e_s \ss ( 3+t ) ( \uu + \dd ) \right ] \tilde{\tilde i}_2 ( h_\gamma ) \nonumber \\ & & + \frac{1}{18}(1-t ) \left [ e_u \dd m_d + e_d \uu m_u - e_s ( \dd m_d + \uu m_u ) \right ] f_{3 \gamma}i'_1({\cal a - v},1-v ) \nonumber \\ & & - \frac{1}{9 } \ss ( e_u \uu + e_d \dd ) \left [ i_1({\cal s } - \tilde { \cal s}+{\cal t}_2+{\cal t}_4,-1+t+2v ) \right . \nonumber \\ & & \left . + ( 1+t ) i_1 ( { \cal t}_1,1)- ( 1+t ) i_1 ( { \cal t}_3,1 - 2v ) \right ] \nonumber \\ & & -e_s \frac{\ss}{9}(\uu + \dd ) \left [ ( -1+t ) i_1({\cal s}+\tilde { \cal s}+ { \cal t}_2-{\cal t}_4,1 ) + 2 i_1 ( { \cal s}- t \tilde { \cal s}+{\cal t}_2+t{\cal t}_4,v ) \right . \nonumber \\ & & \left . -2 ( 1+t ) i_1 ( { \cal t}_1,1 ) + 2 ( 1+t ) i_1 ( { \cal t}_3,1 - 2v ) \right ] \nonumber \\ & & + \frac{1}{9 } \uu \dd ( e_u + e_d ) \left [ 2 ( -1+t ) i_1 ( { \cal s}+{\cal t}_2,1 ) + 4 i_1({\cal s}+{\cal t}_2,v ) -2 ( 1+t ) i_1 ( \tilde{\cal s}-{\cal t}_4,v ) \right . \nonumber \\ & & \left . -(1+t)i_1 ( { \cal t}_1,1 ) + ( 1+t ) i_1({\cal t}_3,1 - 2 v ) \right ] \label{sig9}\end{aligned}\ ] ] @xmath107 \left ( \gamma_e - \ln \frac{m^2}{\lambda^2 } \right ) \nonumber \\ & & + \frac{m_0 ^ 2}{72 \pi^2 m^2}(1-t ) u_0 \bar u_0 \left ( e_u ( \dd m_d + \ss m_s ) \right . \nonumber \\ & & \left . + e_d ( \uu m_u + \ss m_s ) -2 e_s ( \uu m_u + \dd m_d ) \right ) \nonumber \\ & & + \frac{\bar u_0}{24 m^2 } ( 1-t ) \left ( e_u ( \dd m_d + \ss m_s ) + e_d ( \uu m_u + \ss m_s ) \right . \nonumber \\ & & \left . -2 e_s ( \uu m_u + \dd m_d ) \right ) f_{3 \gamma } \left ( \psi^a(u_0 ) - 4 \tilde i_2(\psi^v ) \right ) \nonumber \\ & & + \frac{\bar u_0}{3 m^2 } \left [ e_u \uu ( 2 \dd - ( 3+t)\ss ) + e_d \dd ( 2 \uu - ( 3+t ) \ss ) \right . \nonumber \\ & & \left . + e_s \ss ( \uu + \dd ) ( 1+t ) \right ] \tilde { \tilde i}_2(h_\gamma ) \nonumber \\ & & + \frac{2}{9 m^2 } \left [ e_s \ss ( 1+t ) ( \dd + \uu ) \tilde i_1 \left({\cal t}_2 - { \cal t}_4,1-v \right ) \right . \nonumber \\ & & \left . + \uu \dd ( e_u + e_d ) \tilde i_1 \left({\cal t}_2 - { \cal t}_4 , 1+t-2 v\right ) \right . \nonumber \\ & & \left . - \ss ( e_d \dd + e_u \uu ) \tilde i_1 \left ( { \cal t}_2 - { \cal t}_4,2 + 2 t - ( 3+t)v \right ) \right ] \nonumber \\ & & - \frac{f_{3 \gamma}}{18m^2 } ( 1-t ) \left [ ( e_u + e_d ) m_s \ss \left ( i_1({\cal a}-{\cal v},1 ) + 2 i_1 ( { \cal v},1-v ) \right ) \right . \nonumber \\ & & \left . - \left(e_u m_d \dd + e_d m_u \uu \right ) i_1 ( { \cal a}-{\cal v},v ) \right . \nonumber \\ & & \left . - e_s \left ( \uu m_u + \dd m_d \right ) i_1 ( { \cal a}+{\cal v},1-v ) \right ] \nonumber \\ & & + \frac{m_0 ^ 2}{216 m^4 } ( 1-t ) \bar u_0 \left ( e_u ( \dd m_d + \ss m_s ) + e_d ( \uu m_u + \ss m_s ) \right . \nonumber \\ & & \left . - 2 e_s ( \uu m_u + \dd m_d ) \right ) f_{3 \gamma } \left ( 4 \tilde i_2(\psi^v ) - \psi^a ( u_0 ) \right ) \nonumber \\ & & + \frac{m_0 ^ 2}{54 m^4 } \bar u_0 \left[(-5+t ) ( e_u + e_d ) \uu \dd - 5 e_s ( 1+t ) \ss ( \uu + \dd ) \right . \nonumber \\ & & \left . + 2 \ss ( 5 + 2t)(e_d \dd + e_u \uu ) \right ] \tilde{\tilde i}_2(h_\gamma ) \nonumber \\ & & - \frac{1}{96 \pi^2 } ( 1-t)\bar u_0 \left(e_u + e_d - 2 e_s\right ) m^2 f_{3 \gamma } \left ( 4 \tilde i_2(\psi^v ) - \psi^a(\bar u_0 ) \right ) \nonumber \\ & & - \frac{1}{24 \pi^2 } ( 1-t)\left ( e_u + e_d - 2 e_s\right ) m^2 f_{3 \gamma } i_1({\cal a } + { \cal v},1-v ) \nonumber \\ & & - \frac{1}{6\pi^2 } \left [ ( e_d \dd m_u + e_u \uu m_d ) \left ( ( -1+t ) \tilde i_1({\cal t}_1 - { \cal t}_3,1 ) + 2 \tilde i_1({\cal t}_2 - { \cal t}_4,t - v ) \right ) \right . \nonumber \\ & & - e_s \ss ( m_u + d_d ) \left ( ( -1+t ) \tilde i_1({\cal t}_1-{\cal t}_3,1 ) - ( 1+t ) \tilde i_1({\cal t}_2-{\cal t}_4,1-v ) \right ) \nonumber \\ & & \left . - m_s ( e_d \dd + e_u \uu ) \left ( ( 1 + 3 t ) \tilde i_1({\cal t}_2-{\cal t}_4,1 ) -(3+t ) \tilde i_1({\cal t}_2-{\cal t}_4,v ) \right ) \right ] \nonumber \\ & & - \frac{1}{16 \pi^2 } u_0 \bar u_0 ( 1-t ) \left ( e_u ( \dd m_d + \ss m_s ) + e_d ( \uu m_u + \ss m_s ) - 2 e_s ( \uu m_u + \dd m_d ) \right ) \nonumber \\ & & - \frac{\bar u_0}{8\pi^2 } \left [ e_u \uu ( 2 m_d - ( 3+t ) m_s ) + e_d \dd ( 2 m_u- ( 3+t ) m_s ) \right . \nonumber \\ & & \left . + e_s \ss ( m_u+m_d ) ( 1+t)\right ] \tilde{\tilde i}_2(h_\gamma ) \nonumber \\ & & \label{sig12}\end{aligned}\ ] ] where @xmath108 , @xmath109 are the borel parameters . the contributions of the continuum and the higher states are subtracted using the quark hadron duality by replacing @xmath110 by @xmath111 and replacing @xmath112 by @xmath113 for @xmath114 , where @xmath115 , @xmath116 is the continuum threshold , @xmath117 where @xmath118 is the digamma function . the functions @xmath119 appearing in eqs . ( [ sig6]-[sig12 ] ) are defined as : @xmath120 where @xmath121 when there is no integration over @xmath122 , @xmath123 and @xmath124 . since , for the reactions under considerations , @xmath125 , we will set the borel parameters to be equal , i.e @xmath126 and @xmath127 . in order to obtain the values of the moments @xmath73 , ( @xmath74 ) , we also need the expression for the residues . the residues can be obtained from the mass sum rules . for completeness , we also include the mass sum rules that we used to obtain the values of the residues @xcite : @xmath128 \nonumber \\ & & - \frac{1}{64 \pi^2}(-1 + t)^2 \left(\dd m_u + \uu m_d \right ) m^2 e_0(x ) \nonumber \\ & & - \frac{3}{64 \pi^2 } ( -1+t^2 ) \left ( m_s ( \dd + \uu ) + \ss ( m_u + m_d ) \right ) m^2 e_0(x ) \nonumber \\ & & + \frac{1}{128 \pi^2 } ( 5 + 2 t + 5 t^2 ) \left ( \uu m_u + \dd m_d + \ss m_s \right ) \nonumber \\ & & + \frac{1}{24 } \left [ 3 \ss ( \dd + \uu ) \left(-1+t^2\right ) + ( -1+t)^2 \uu \dd \right ] \nonumber \\ & & + \frac{m_0 ^ 2}{256 \pi^2 } ( -1+t)^2 \left(m_d \uu + m_u \dd \right ) \nonumber \\ & & + \frac{m_0 ^ 2}{256 \pi^2 } ( -1+t^2 ) \left [ 13 m_s ( \uu + \dd ) + 11 \ss ( m_d + m_u ) \right ] \nonumber \\ & & - \frac{m_0 ^ 2}{192 \pi^2 } ( 1+t+t^2 ) \left(\uu m_u + \dd m_d -2 m_s \ss \right ) \label{masssigma0}\end{aligned}\ ] ] and @xmath129 where @xmath130 . ( the mass sum rule for the @xmath82 baryon can be obtained from eq . ( [ masssigma0 ] ) using the relation given in @xcite ) note that , from the mass sum rules , one can only obtain the square of the residues . hence , from the mass sum rules it is not possible to deduce the sign of the residues . thus , in this work , we can not predict the absolute sign of the moments . for comparison with the experimental data , we will also consider the following ratio : @xmath131 although we do not predict the sign of @xmath35 and @xmath34 separately , the sign of @xmath132 is predicted by light cone qcd sum rules . our sign convention for the residues are such that @xmath133 and @xmath134 as @xmath135 . an interesting limit to consider is the @xmath59 limit , i.e. the limit @xmath136 and @xmath137 , which allows one to establish relationship between the transition amplitudes . in this limit , ( [ sig6]-[sig12 ] ) are proportional to @xmath138 . using eq . ( [ subs ] ) , one obtains the following relations : @xmath139 which are the well known @xmath59 relationships . note that , eq . ( [ su3 ] ) imply that @xmath132 is the same for all considered processes . here , we should remind once more that the signs are not predictions of the lcqsr , only relative factors up to a sign are reproduced by the lcqsr . the original sign convention is chosen such that the @xmath60 relations are reproduced including the signs . since we are neglecting the masses of the @xmath140 and @xmath141 quarks and the differences in their condensates , isospin subgroup of @xmath59 remains unbroken . hence , the relations @xmath142 still holds in the approximation that we are considering . at the end of this section , we present the decay width for the decay @xmath143 in terms of the multipole moments @xmath35 and @xmath34 : @xmath144 or in terms of the helicity amplitudes used by pdg @xcite : @xmath145 where @xmath146 is the energy of the photon and the helicity amplitudes are defined as : @xmath147 where @xmath148 for the numerical values of the input parameters , the following values are used : @xmath149 , @xmath150 , @xmath151 @xcite , @xmath152 @xcite , @xmath153 and @xmath154 @xcite . the photon wave functions are : @xcite @xmath155 \nonumber \\ { \cal t}_1(\alpha_i ) & = & -120 ( 2 \zeta_2 + \zeta_2^+)(\alpha_{\bar q } - \alpha_q ) \alpha_{\bar q } \alpha_q \alpha_g \nonumber \\ { \cal t}_2(\alpha_i ) & = & 30 \alpha_g^2 ( \alpha_{\bar q } - \alpha_q ) \left((\kappa - \kappa^+ ) + ( \zeta_1 - \zeta_1^+)(1 - 2\alpha_g ) + \zeta_2 ( 3 - 4 \alpha_g)\right ) \nonumber \\ { \cal t}_3(\alpha_i ) & = & - 120 ( 3 \zeta_2 - \zeta_2^+)(\alpha_{\bar q } -\alpha_q ) \alpha_{\bar q } \alpha_q \alpha_g \nonumber \\ { \cal t}_4(\alpha_i ) & = & 30 \alpha_g^2 ( \alpha_{\bar q } - \alpha_q ) \left((\kappa + \kappa^+ ) + ( \zeta_1 + \zeta_1^+)(1 - 2\alpha_g ) + \zeta_2 ( 3 - 4 \alpha_g)\right)\end{aligned}\ ] ] the constants appearing in the wave functions are given as @xcite @xmath156 , @xmath157 , @xmath158 , @xmath159 , @xmath160 , @xmath161 , @xmath162 , @xmath163 and @xmath164 once the input parameter are determined , the next task is to find the continuum threshold , @xmath116 , and a suitable region of the borel mass , @xmath165 , for each of the processes . to find an upper bound for the borel mass parameter , @xmath165 , we required the continuum contribution to be less then the contribution of continuum subtracted sum rules , and requiring that the contribution of the highest power of @xmath166 be less than @xmath167 of the highest power of @xmath165 , gave a lower bound on @xmath165 . using these constraints we found that for @xmath168 transitions , @xmath169 and @xmath170 ; for the @xmath171 and @xmath172 transitions , @xmath173 and @xmath174 ; and for the @xmath175 transitions , @xmath173 and @xmath176 . in figs . ( [ ge.deltap.proton.th ] ) and ( [ ge.deltap.proton.9.12.th ] ) , we depict the dependence of @xmath177 obtained from @xmath178 and @xmath179 , and @xmath180 and @xmath179 , respectively , on @xmath181 , where @xmath182 is defined through @xmath183 for the decays @xmath42 . two common features of these graphs are that they become large near @xmath184 , and they go to zero at some finite value of @xmath181 these behavior can be understood in the following way : the correlation function eq . ( [ eq1 ] ) is a linear function of @xmath79 . from the correlation function , one can only obtain the product @xmath185 , and hence this product , obtained from the correlation function , is also a linear function of @xmath79 . in particular , there is a point @xmath186 at which this product goes to zero . on the other hand , from the definition of @xmath187 , ( [ eq4 ] ) , it is also seen that the residue is also a linear function of @xmath79 , which has to be determined using the mass sum rules eq . ( [ masssigma0 ] ) , and consequently there is a point @xmath188 at which the residue goes to zero . if one could make an exact calculation of the correlation function eq . ( [ eq1 ] ) and the mass sum rule eq . ( [ masssigma0 ] ) , then one should obtain @xmath189 , but due to the approximations used , these two points do not coincide . this is reflected in figs . ( [ ge.deltap.proton.th ] ) and ( [ ge.deltap.proton.9.12.th ] ) as a point at which @xmath190 go to zero ( at @xmath186 ) and a point at which @xmath190 becomes very large ( near @xmath188 ) . these points and any region between them , as well as any enhancement / suppression near these points , is an artifact of the approximations used , and hence the suitable region for @xmath79 should be away from these points . another point to observe comparing these two figures is that in fig . ( [ ge.deltap.proton.th ] ) , the points at which @xmath190 vanishes and that it gets very large are very close together whereas in fig . ( [ ge.deltap.proton.9.12.th ] ) , they are farther apart . in particular , in fig . ( [ ge.deltap.proton.9.12.th ] ) , the ioffe current , which corresponds to @xmath191 , is out of the suitable region for @xmath79 . for the working region of @xmath181 , if one chooses @xmath192 for fig . ( [ ge.deltap.proton.th ] ) , and @xmath193 for fig . ( [ ge.deltap.proton.9.12.th ] ) , one obtains @xmath194 and @xmath195 respectively , i.e. within the respective working regions of @xmath79 , using the sum rules for @xmath178 and @xmath179 or @xmath180 and @xmath179 , the predictions obtained for @xmath35 are in agreement . but due to the better stability of the results obtained using the sum rules for @xmath178 and @xmath179 with respect to variations of @xmath79 and hence a larger working region of @xmath181 , from now on we will present only the results of the sum rules obtained from @xmath178 and @xmath179 . ( [ gm.deltap.proton.th ] ) and ( [ gm.deltap.proton.9.12.th ] ) , are the same as figs . ( [ ge.deltap.proton.th ] ) and ( [ ge.deltap.proton.9.12.th ] ) , but for @xmath196 . the general features of the dependence of @xmath196 on @xmath181 is the same as those of @xmath190 , i.e. fig . ( [ gm.deltap.proton.th ] ) is more stable than fig . ( [ gm.deltap.proton.9.12.th ] ) as a function of @xmath79 and hence has a larger working region for @xmath181 . in figs . ( [ ge.deltap.proton.msq])-([gm.xism.xim.msq ] ) , the dependence of @xmath35 and @xmath34 on @xmath165 for various processes and different values of the continuum threshold is depicted for the ioffe current and the limit @xmath197 ( @xmath198 ) . the ioffe current always gives smaller results due to its vicinity to the point where the correlation function vanishes as a function of @xmath79 . from the figures it is seen that all of the sum rules are stable with respect to small variation of @xmath116 in the region of @xmath165 considered . in table ( [ result ] ) , we show our results for the moments @xmath73 ( @xmath199 ) and also @xmath132 values for the central values of @xmath35 and @xmath34 . for the values in the table , the value of @xmath181 is restricted to be @xmath192 .the predictions on the moments for various decays . the magnetic moments are given in terms of natural magnetons [ cols="<,^,^,^,^,^",options="header " , ] we would like to thank v.s . zamiralov for useful discussions on the relationship between the expressions for the @xmath83 and @xmath82 baryon properties . t.m . would like to thank the high energy section of the abdus salam ictp , trieste , italy , and a.o . would like to thank the physics department of middle east technical university , ankara , turkey where parts of this work is carried out for their hospitality . 99 c. mertz _ et al . * 86 * ( 2001 ) 2963 k. joo _ clas collab . * 88 * ( 2002 ) 122001 m. a. shifman , a.i . vainshtein , and v. i. zakharov , nucl * b147 * ( 1979 ) 385 p. colangelo and a. khodjamirian in `` at the frontier of particle physics : handbook of qcd , '' ed . by m. shifman ( world scientific , singapore , 2001 ) v.3 , 1995 v.m . braun , prep . hep - ph/9801222 ( 1998 ) m.n . butler , m.j . savage and r.p . springer , nucl . b399 * ( 1993 ) 69 m.n . butler , m.j . savage and r.p . springer , phys . lett . * b304 * ( 1993 ) 353 m. napsuciale and j. l. lucio , nucl . phys . * b494 * ( 1997 ) 260 g.c . gellas , t.r . hemmart , c.n . ktorides and g. i. poulis , phys . rev . * d60 * ( 1999 ) 054022 d. arndt and b. c. tiburzu , phys.rev * d69 * ( 2004 ) 014501 d.b . leinweber , t. draper , r.m . woloshyn , phys.rev . * d48 * ( 1993 ) 2230 e. jenkins , x .- d . ji and a.v . manohar , phys . * 89 * ( 2002 ) 242001 b. l. ioffe and a. v. smilga , nucl . b232 * ( 1984 ) 109 t. m. aliev and m. savci , phys . rev . * d60 * ( 1999 ) 114031 f. x. lee , phys.rev . * c57 * ( 1998 ) 322 f. x. lee and x .- y . lui phys . rev . * d66 * ( 2002 ) 014014 a. khodjamirian and d. wyler , preprint hep - ph/0111249 ( 2001 ) . lipkin , phys . rev . * d7 * ( 1973 ) 846 h. f. jones and m.d . scadron , ann . phys . * 81 * ( 1973 ) 1 r. c. e. devenish , t.s . eisenschitz and j. g. krner , phys . rev . * d14 * ( 1976 ) 3063 a.ozpineci , s.b . yakovlev , v.s . zamiralov , preprint , hep - ph/0311271 ( 2003 ) a.ozpineci , s.b . yakovlev , v.s . zamiralov , mod.phys.lett . * a20 * ( 2005 ) 243 p. ball , v. m. braun , n. kivel , nucl . phys . * b649 * ( 2003 ) 263 w .- y . p hwang and k .- c . yang , phys . bf d49 ( 1994 ) 460 f. x. lee , phys.rev . * d57 * ( 1998 ) 1801 s. eidelman _ b592 * ( 2004 ) 1 v. m. belyaev and ya . i. kogan , yad . fiz . * 40 * ( 1984 ) 1035 v. m. belyaev and b. l. ioffe , jetp * 56 * ( 1982 ) 493 a. j. buchmann , e. hernandez , and a. faessler , phys * c55 * ( 1997 ) 448 v.v . [ selex coll . * b590 * ( 2004 ) 161 * the dependence of @xmath200 , obtained from @xmath178 and @xmath179 , on @xmath181 for @xmath201 and @xmath202 for the value of the borel parameter @xmath203 * the same as fig . [ ge.deltap.proton.th ] but for @xmath200 obtained from @xmath180 and @xmath179 * the same as fig . [ ge.deltap.proton.th ] but for @xmath204 * the same as fig . [ ge.deltap.proton.9.12.th ] but for @xmath204 * the dependence of @xmath205 , obtained from @xmath178 and @xmath179 , on the borel parameter @xmath165 for @xmath206 and @xmath202 . the lines with circles on them correspond to the ioffe current , @xmath80 , whereas others correspond to @xmath207 * the same as fig . [ ge.deltap.proton.msq ] but for @xmath208 * the same as fig . [ ge.deltap.proton.th ] , but for the decay @xmath209 and for @xmath210 * the same as fig . [ ge.deltap.proton.msq ] , but for the decay @xmath211 and for @xmath210 * the same as fig . [ ge.sigmasp.sigmap.th ] , but for @xmath212 * the same as fig . [ ge.sigmasp.sigmap.msq ] , but for @xmath213 * the same as fig . [ ge.sigmasp.sigmap.th ] , but for the decay @xmath214 * the same as fig . [ ge.sigmasp.sigmap.msq ] , but for the decay @xmath215 * the same as fig . [ gm.sigmasp.sigmap.th ] , but for the decay @xmath214 * the same as fig . [ gm.sigmasp.sigmap.msq ] , but for the decay @xmath215 * the same as fig . [ ge.sigmasp.sigmap.th ] , but for the decay @xmath216 * the same as fig . [ ge.sigmasp.sigmap.msq ] , but for the decay @xmath217 * the same as fig . [ gm.sigmasp.sigmap.th ] , but for the decay @xmath216 * the same as fig . [ gm.sigmasp.sigmap.msq ] , but for the decay @xmath217 * the same as fig . [ ge.sigmasp.sigmap.th ] , but for the decay @xmath218 * the same as fig . [ ge.sigmasp.sigmap.msq ] , but for the decay @xmath219 * the same as fig . [ gm.sigmasp.sigmap.th ] , but for the decay @xmath218 * the same as fig . [ gm.sigmasp.sigmap.msq ] , but for the decay @xmath219 * the same as fig . [ ge.sigmasp.sigmap.th ] , but for the decay @xmath220 and for the borel parameter @xmath221 * the same as fig . [ ge.sigmasp.sigmap.msq ] , but for the decay @xmath222 and for the borel parameter @xmath221 * the same as fig . [ gm.sigmasp.sigmap.th ] , but for the decay @xmath220 and for the borel parameter @xmath221 * the same as fig . [ gm.sigmasp.sigmap.msq ] , but for the decay @xmath222 and for the borel parameter @xmath221 * the same as fig . [ ge.sigmasp.sigmap.th ] , but for the decay @xmath223 and for the borel parameter @xmath221 * the same as fig . [ ge.sigmasp.sigmap.msq ] , but for the decay @xmath224 and for the borel parameter @xmath221 * the same as fig . [ gm.sigmasp.sigmap.th ] , but for the decay @xmath223 and for the borel parameter @xmath221 * the same as fig . [ gm.sigmasp.sigmap.msq ] , but for the decay @xmath224 and for the borel parameter @xmath221

the radiative decays of decuplet to octet baryons are analyzed within the light cone qcd sum rules framework.the electromagnetic transition form factors for these decays are calculated at @xmath0 up to twist four accuracy for photon wave functions as well as including first order strange quark mass corrections . a comparison of our results with predictions of lattice theory and existing experimental data is presented . |s s # 1#2#3 @xmath1 # 1#2#3 @xmath1

chronic subdural hematoma ( csdh ) is a common form of intracranial hemorrhage that correlate significantly with morbidity.11,18,33 ) management of csdh is non - surgical or surgical . neurosurgeons have performed various surgical techniques , such as burr - hole craniotomy with or without continuous closed - system drainage,2,16,17,21 ) small craniotomy with endoscopic removal,23 ) and large craniotomy followed by , hematoma removal with membranectomy.8 ) the prognosis after surgery is usually good because of development of modern imaging methods , and improvement in surgical techniques.32 ) unilateral csdh occurs in the majority of patients , but bilateral csdh is occasionally found in neurosurgical practice . the overall incidence of bilateral csdh has been reported to vary from 16% to 20%.4,20,22 ) kurokawa et al.13 ) reported bilateral csdh cases should be treated with simultaneous decompression of bilateral hematoma pressure as early as possible . the recurrence rate has been variably reported to be significantly higher in patients with bilateral csdh than in those with unilateral csdh.14,20 ) another study has reported that bilateral csdh is an independent predictor of csdh recurrence.27 ) although bilateral csdh has been studied in previous studies , there are few studies comparing the clinical characteristics of bilateral and unilateral csdh cases . the purpose of this study was to analyze clinical presentations , precipitating factors , computed tomography ( ct ) findings , postoperative complications , and outcomes of bilateral csdh compared with unilateral csdh . a total of 131 patients with csdh who were treated at dongguk university ilsan hospital from january 2005 through january 2013 were enrolled in this study . this study excluded patients with 1 ) concomitant traumatic brain injury ( n=3 ) , 2 ) csdh due to complications of prior neurosurgical procedures ( n=10 ) , such as cerebrospinal fluid shunting or craniotomy , and 3 ) conservative treatment without surgery ( n=4 ) . finally , 114 patients were included in the study and were divided into the bilateral and unilateral csdh groups . clinical presentations of the 114 patients were documented at the emergency department or the outpatient clinic . presenting symptoms included headache , dizziness , altered consciousness , hemiparesis , dysarthria , gait disturbance , and seizure . all patients underwent brain ct scan or magnetic resonance imaging ( mri ) immediately after arrival at the emergency department or the outpatient clinic , and csdh was confirmed by ct and mri . brain ct scans were interpreted on the basis of the following findings : 1 ) the thickness of hematoma measured at the maximal diameter ; 2 ) the location of hematoma ( unilateral or bilateral cerebral convexity ) ; 3 ) midline shift as measured by using deviation of the septum pellucidum from the central position ; and 4 ) hounsfield units of hematoma at the site of the highest density ( hypodense , isodense , hyperdense , or mixed ) . all patients underwent drilling of burr holes on the side of the subdural hematoma and irrigation of the subdural space with normal saline . all patients had closed - system drainage , with the aid of a silicone tube indwelled in the subdural space and tunneled under the scalp to the exit point of the incision line . local recurrence was defined as recurrence of csdh that required reoperation due to clinical and radiological aggravation . the radiological aggravation consisted of an increase in the thickness of hematoma on follow - up ct scans within 3 months postoperatively . modified rankin scale ( mrs ) scores were measured by the neurosurgeons when patients were discharged from the hospital and revisited the outpatient clinic within 3 months postoperatively . we assessed the outcomes of csdh using the mrs at discharge and 3 months postoperatively . postoperative complications included acute subdural hemorrhage , infection , new - onset seizure , pneumocephalus , and hydrocephalus . this study is of retrospective design , and it analyzed data , including clinical presentations , precipitating factors , ct findings , postoperative complications , and outcomes . comparisons between the 2 groups were made by using the independent samples t - test and crosstabs analysis . the mean age was 77.85 years in the bilateral csdh group and 72.86 years in the unilateral csdh group ( p=0.033 ) . the mean age is older in the bilateral csdh group than in the unilateral csdh group . the female / male ratios were 6:22 in the bilateral csdh group and 27:59 in the unilateral csdh group . the characteristics and clinical presentations of the patients in both groups are shown in table 1 . the most common symptom was altered consciousness in the bilateral csdh group and headache in the unilateral csdh group . other clinical presentations included gait disturbance , dizziness , hemiparesis , speech disorder , and seizure . altered consciousness and gait disturbance were significantly more common in the bilateral csdh group than in the unilateral csdh group ( p=0.015 ) . history of head injury was present in 64.3% of patients in the bilateral csdh group and 60.5% of patients in the unilateral csdh group . history of diabetes mellitus was observed in 13 patients ( 46.4% ) in the bilateral csdh group and 14 patients in the unilateral csdh group ( 16.3%)(p=0.001 ) . other precipitating factors and concurrent systemic diseases of csdh were hypertension , history of smoking or alcohol intake , cerebrovascular disease , heart disease , renal disease , and liver disease . the density of hematoma on ct scans was categorized into hypodensity , hyperdensity , isodensity , or mixed density ( table 3 ) . no significant difference was found in the density of hematoma on ct scans between the 2 groups . the mean degree of midline shift on ct scans was a significantly greater in the unilateral csdh group than in the bilateral csdh group ( p=0.001 ) . the postoperative complications and outcomes of the patients in the 2 groups are shown in table 4 . recurrence was found in 6 patients ( 21.4% ) in the bilateral csdh group and 14 patients ( 16.3% ) in the unilateral csdh group , but the difference was not statistically significant . overall favorable outcome ( mrs 0 - 2 ) was achieved in 85.9% of patients in all patients , 67.8% of patients in the bilateral csdh group , and 91.8% of patients in the unilateral csdh group . the mean mrs at discharge was 1.5 in the bilateral csdh group and 0.6 in the unilateral csdh group ( p=0.019 ) . the mean mrs at the outpatient clinic within 3 months postoperatively was 0.89 in all patients , 1.5 in the bilateral csdh group , and 0.7 in the unilateral csdh group ( p=0.063 ) . one patient who belonged to unilateral group died of pneumonia during treatment ( table 5 ) . this is close to the incidences of previous studies that have been reported to vary from 16% to 20%.4,20,22 ) the mean age of csdh patients in this study was 74 years . spallone et al.26 ) have reported that bilateral csdh tends to occur in patients older than 75 years . in this study , the mean age of the patients was 77 years in the bilateral csdh and 72 years in the unilateral csdh group . the mean age was older in the bilateral csdh group than in the unilateral cdsh group ( p=0.033 ) . csdh is more common in elderly subjects because of age - related decreases in brain volume and increases in venous fragility.1,26 ) this increases tension on the cerebral bridge veins , and the greater movement of the brain within the cranium makes these veins vulnerable to trauma.5,28 ) thus , we thought that elderly subjects were more likely to develop bilateral csdh . csdh predominantly occurred in males , with no significant difference between the 2 groups . in this study , headache is the most common symptom in all patients . the incidence of headache varies among different studies , ranging from 14% to 80%.6,10 ) adhiyaman et al.1 ) have shown that the most common presentation in elderly subjects ( 50 - 70% ) is altered consciousness which manifests as varying degrees of confusion , drowsiness , or coma . tsai et al.29 ) have suggested that bilateral csdh has symptoms of raised intracranial pressure more frequently than unilateral csdh . in our study , altered consciousness was the most common presentation and more common in the bilateral csdh group than in the unilateral csdh group . okuyama et al.19 ) measure cerebral blood flow ( cbf ) in 34 patients with bilateral csdh and the cbf reductions are showed in the frontal , parietal and occipital cortices in the thin hematoma side , and in the putamen in the thick hematoma side in the brain shifted group . huang et al.9 ) suggested that the shifted force of csdh is accompanied by a secondary cbf reduction in the deep cerebral regions which is a major cause of neurological dysfunction and patients with a bilateral csdh have less opportunity for central brain structures to deviate owing to counterbalance of the mass effect on both sides . we found that the mean degree of midline shift on ct scans was a significantly greater in the unilateral csdh and supposed that shifted force was easily accompanied in unilateral sdh group . rust et al.25 ) have indicated that anticoagulant therapy can be used in a significant percentage of patients with csdh . tsai et al.29 ) have reported that the frequency of anticoagulant and antiplatelet use is significantly higher in the bilateral csdh group than in the unilateral csdh group . in this study , however , the frequency of taking antiplatelets or anticoagulants showed no significant difference between the 2 groups . kim et al.12 ) have demonstrated that the presence of diabetes mellitus is significantly related to poor prognosis . cheung et al.3 ) have reported that history of diabetes mellitus is the only patient characteristic that markedly increases the risk of intracranial hemorrhage in surgically treated patients . diabetes mellitus is also a significant predictor of mortality after moderate to severe traumatic brain injury.15 ) the pathophysiology of csdh has not yet been fully elucidated . some studies have reported that increased permeability of the capillaries in the outer membrane of hematoma can cause the enlargement of csdh.7,34 ) vascular permeability activates the kallikrein system which may cause blood extravasation and plasma exudation . fujisawa et al.7 ) have shown that the kallikrein system is activated histologically and biochemically in the outer membrane of hematoma . increased capillary permeability is an early phenomenon in diabetes mellitus that affects the microvasculature of the brain and many other organs.31 ) clinical and experimental evidence suggests that hyperglycemia may impair autoregulation and increase permeability in microvessels.35 ) this leads us to assume that patients with diabetic mellitus are likely to develop bilateral csdh rather than unilateral csdh in spite of the same traumatic stress to the head . most of the csdh patients have good outcomes after surgical treatment.1,26 ) surgical treatment of csdh improves neurological recovery and radiologic findings . in previous studies , postoperative outcomes were no significant differences between the bilateral and unilateral csdh groups.9 ) whereas in this study they were poorer in the bilateral csdh group . van havenbergh et al.30 ) have reported that the only statistically significant factor for clinical outcomes is the neurological condition at the time of treatment . rozzelle et al.24 ) have documented that patients with glasgow coma scale under 7 on admission have high mortality rates . in our study , the initial neurological state was poor in the bilateral csdh group compared to the unilateral csdh group . furthermore , in the bilateral csdh group , some patients were in a very poor neurologic state that included coma or stupor at the time of treatment and showed a poor outcomes at discharge ( mrs 4 - 6 ) . huang et al.9 ) have suggested that patients with bilateral csdh may present with vague symptoms found incidentally during workup . therefore , a delayed or missed diagnosis of csdh is more common in patients with bilateral csdh . bilateral csdh cases show rapid and progressive aggravation , and thus they should be treated as early as possible , even if they show minimal neurologic deficits.17 ) the limitation of this study was its retrospective design . in this study , data was collected through medical records and imaging reviews and thus less accurate than that in prospective studies . the duration of evaluation of neurological outcomes was only within 3 months postoperatively , and follow - up information was difficult to obtain in cases of no revisit to the outpatient clinic . we did not analyze correlations between prognosis and hba1c which shows the average level of blood glucose . the patients of bilateral csdh seem to reveal worse mental status and neurologic sign than unilateral csdh in both baseline and postoperative state .

objectivechronic subdural hematoma ( csdh ) is a common intracranial hemorrhage that is associated with significant morbidity . bilateral lesions are occasionally found in neurosurgical practice . the purpose of this study is to analyze clinical characteristics of bilateral csdh compared with unilateral csdh.methodsbetween january 2005 and january 2013 , the authors treated 114 surgical patients with csdh . clinical presentations , precipitating factors , computed tomography ( ct ) findings , postoperative complications , and outcomes of patients were retrospectively analyzed in the bilateral and unilateral csdh groups.resultsbilateral csdh was identified in 28 ( 24.6% ) of the 114 csdh patients . the mean age was 77.85 years in the bilateral csdh group . the frequency of altered consciousness as a presenting symptom was significantly higher in the bilateral csdh , and that of hemiparesis was significantly higher in the unilateral csdh ( p=0.015 ) . diabetes mellitus was more common in the bilateral csdh ( p=0.001 ) . ct scans revealed significant differences in the degree of midline shift ( p=0.001 ) . the mean modified rankin scale at discharge was 1.5 in the bilateral csdh group and 0.6 in the unilateral group ( p=0.019).conclusionbilateral csdh showed different clinical characteristics from unilateral csdh . bilateral csdh is prone to occurrence in the patient of old and diabetics . the patients of bilateral csdh seem to reveal worse mental status and neurologic sign than unilateral csdh in both baseline and postoperative state .

Adam Schefter breaks down the negotiations that continued to fall short for a new stadium in San Diego. Schefter also examines what could prevent the Chargers' move to L.A. (2:00) Almost one year to the day since the Rams moved to Los Angeles, the Chargers now likely intend to do the same. The Chargers plan to announce as early as Thursday that they are moving to Los Angeles for the 2017 season, league sources said, ending a 55-year stint in San Diego and returning to their birthplace. The franchise played its inaugural season in Los Angeles in 1960 before moving to San Diego in 1961. The Chargers have notified NFL commissioner Roger Goodell and other league owners of their plan, sources said. As one league source cautioned Wednesday night, Chargers chairman Dean Spanos had yet to send a formal relocation letter to the NFL or notify public officials in Los Angeles or San Diego of the team's move -- or even tell the members of the Chargers organization about his plans. The source insisted nothing is final. But unless Spanos unexpectedly changes his mind at the last moment -- and there certainly have been plenty of plot twists in San Diego's stadium saga -- the Chargers will be moving to Los Angeles. A team employee told The Associated Press that the Chargers have scheduled an 11 a.m. ET staff meeting for Thursday, the topic of which hadn't been divulged. "At first, I hoped it was fake news. It's something that is unfathomable, but it is reality," Chargers great Dan Fouts said of the move. This has been an extremely difficult decision for Spanos, sources said. While the economics of the decision have been clear, Spanos' loyalty and connection to San Diego have provided a counterbalance. But Spanos has worked to find a new stadium for his team for 16 years, and there's no resolution in sight. This stalemate is occurring at a time when the Rams are becoming more established in the Los Angeles market. Sources said Spanos believes he needs to start fighting for the Los Angeles market as soon as possible. With the move, the Chargers would become the second team in less than a year to move to Los Angeles, after the city went more than two decades without having one. Chargers wideout Keenan Allen told ESPN's Josina Anderson of the expected move: "It's different to hear the Los Angeles Chargers, but it should be dope." Defensive tackle Corey Liuget told Anderson he was surprised by the news. "More than anything, I'm shocked," he said. "I didn't think it was going to happen. I thought we were going to stay in San Diego. ... I thought something would've got done and worked out. ... So I guess L.A. is our new home then." The Chargers applied for relocation to Los Angeles last year, but the franchise's proposed stadium project with the Oakland Raiders in Carson, California, was voted down in favor of Rams owner Stan Kroenke's project, a $2.66 billion stadium in Inglewood scheduled to open in 2019. Chargers chairman Dean Spanos has faced intense criticism and heckling in the team's first week in Los Angeles. AP Photo/Phelan M. Ebenhack The Chargers have not announced where they would play home games over the next two seasons. A possible -- if not likely -- destination next season is the StubHub Center in Carson, where the MLS' LA Galaxy play. The stadium holds about 27,000 and could be expanded to 30,000. In December, the Chargers announced they had entered into an agreement to lease land for a temporary training facility in Orange County, should they exercise the Jan. 15 option (one the NFL extended to Jan. 17) to move to Los Angeles. The Chargers agreed to lease part of a Costa Mesa office campus along with a nearby 3.2 acres to serve as the initial location of the team's office headquarters and practice and training facilities. San Diego Mayor Kevin Faulconer's last-ditch proposal to keep the team was a projected $1.2 billion new stadium in Mission Valley -- the current site of Qualcomm Stadium -- that included a potential $375 million in public contribution. However, there remained a $175 million gap in funding after the NFL and the Chargers contributed $650 million, and the team had reservations that a vote for public funding would not pass in San Diego, along with potential environmental and legal entanglements at the Mission Valley site. The Chargers received just 43 percent support in November on the team's $1.8 billion downtown stadium and convention center annex that proposed raising the city's hotel tax to help fund the project. By leaving San Diego, the Chargers would leave behind a loyal fan base that cheered for Fouts, Charlie Joiner and Kellen Winslow Sr. during the Air Coryell years in the 1970s and early 1980s and for Junior Seau, Stan Humphries and Natrone Means during the Chargers' only Super Bowl run in 1994. Sources said a news conference to address the move is tentatively scheduled for Wednesday in Los Angeles. Information from ESPN's Jim Trotter, Eric Williams and Ramona Shelburne was used in this report. ||||| Chargers Chairman Dean Spanos has called an 8 a.m. staff meeting for Thursday, at which time he is expected to inform his employees that the franchise is moving from San Diego, its home of 56 years, to Los Angeles. The move was first reported Wednesday night by ESPN, although the story’s author, Adam Schefter, also said that a league source cautioned that “Spanos has yet to send a formal relocation letter to the NFL, yet to notify public officials in Los Angeles or San Diego of the team's move, or even tell the members of the San Diego organization about his plans. The source insisted nothing is final.” But, Schefter wrote, “the Chargers have notified NFL commissioner Roger Goodell, and other league owners, of their intent to move to Los Angeles for the 2017 season.” Multiple sources confirmed the staff meeting, with one saying Spanos planned to be in Los Angeles later Thursday. Another league source said of the plan to move, “All I can tell you is my understanding is it is true.” A spokesman for Mayor Mayor Kevin Faulconer had no word from the team about a move. “The Chargers have not contacted the city,” spokesman Matt Awbrey said in an email Wednesday night. County Supervisor Ron Roberts, who had worked with Faulconer on a San Diego stadium proposal, said: “If reports are true the Chargers are moving, it's disappointing. But you can only do so much.” Charger fans were disheartened, especially with recent talk suggesting the team might stay, at least a while longer, in an attempt to work out a stadium deal. “I am a lifelong Chargers fan,” said Richard Wade, managing editor of the Bolts from the Blue website. “And as such, I find it incredibly appropriate as well as exceptionally painful that they got my hopes up one last time before dashing them as time was expiring.” On Twitter, Chris Holloway ‏posted: “Plaza Section 43, Row 16, Seats 3-4. My family has had these seats for over 20 years. Even if inevitable, tonight hurts, bad.” At some point Wednesday night the Chargers’ headquarters in Murphy Canyon was egged. Later, a San Diego police patrol car was parked outside the building. The Chargers' headquarters on Murphy Canyon Road was egged Wednesday night after reports that Chairman Dean Spanos is set to announce the team will move to Los Angeles. The Chargers' headquarters on Murphy Canyon Road was egged Wednesday night after reports that Chairman Dean Spanos is set to announce the team will move to Los Angeles. SEE MORE VIDEOS Civic leader Phil Blair, CEO of Manpower San Diego, said he would be surprised if the Chargers had really decided to leave San Diego for Los Angeles. While the team owner may believe there's a larger financial reward being in Los Angeles, Blair says he's not so sure. "I can't see them being second fiddle to the Rams or being a tenant in someone else's stadium," said Blair, a former member of San Diego's Convention Center Corp. board. "Is it a financial decision where I as the owner want to go where the profits are or is this a family company that loves San Diego and really wants to make it work? I think moving to L.A., long-term, is a mistake." Most players learned of the news Wednesday evening just how fans did: on social media. Chargers cornerback Jason Verrett said that he was on the phone with safety Jahleel Addae when Addae, who was logged onto Twitter, blurted out that it’d been reported the team was relocating to Los Angeles. Some mixed feelings followed, as both have spent the entirety of their careers in San Diego. Addae arrived in 2013 as an undrafted rookie. Verrett, a Pro Bowler, followed as a 2014 first-round pick. “I didn’t believe it at first,” Verrett said. “I was like, ‘Man, I ain’t going to believe it until the announcement.’ But once I saw it on Twitter, I was like, ‘Damn, it’s crazy.’ They finally made a decision on where we’re going to be. Of course, San Diego is the city that drafted me. I was looking forward to it being my home.” Similarly, other players were surprised to learn the news. “Wow!” one said via text message. Those reached were still processing the development, waiting for an official announcement. But there clearly was relief among players toward the prospect of having clarity about the franchise's location, both for them and their families. The Chargers have been seeking a new stadium in San Diego for more than 15 years, and a year ago were given a deadline of Jan. 15 to move to a stadium the Rams are building in Inglewood. Earlier Wednesday, the NFL extended that deadline by two days, to Tuesday. The lack of a modern football stadium in San Diego — and the additional revenues generated by such elaborate facilities — prompted the departure of the team, which has been one of the region’s most popular and recognizable civic institutions. The Chargers have agreed to become tenants in a $2.66 billion stadium Los Angeles Rams owner Stan Kroenke is building in Inglewood. It has not been announced where the Chargers would play before that stadium opens in 2019, but most speculation has been it will be at StubHub Center in Carson, which seats fewer than 30,000. The report of the move comes two months after San Diego voters rejected a tax increase for a combined stadium and convention center annex the Chargers proposed for downtown. Measure C was supported by 43.6 percent of voters, far less than the two-thirds required for approval. That proposal came after the team pursued at least nine different stadium solutions beginning in 2004, though some say many of those proposals lacked financial details. In fall 2015, the Chargers declined to consider a proposal from county and city officials for a new stadium in Mission Valley on the site of the team’s current home — Qualcomm Stadium, which opened in 1967. While experts say the local economic damage from the team’s departure will probably be minor at the most, San Diego’s image could suffer outside the city and local community pride could take a hit, especially among the team’s more enthusiastic fans. The Chargers’ pending departure would leave San Diego with only one franchise among the nation’s four major sports leagues: the Padres. The Clippers’ departure in 1984 cost the city its NBA franchise, and San Diego has never had an NHL team.

– A shocker for San Diego fans: The Chargers are planning to move to Los Angeles, saying farewell to San Diego after 56 years in the city, sources tell ESPN. Insiders say the team has scheduled a Thursday morning staff meeting in which the move will be announced. NFL commissioner Roger Goodell has been told about the team's plan to move for the 2017 season, sources say, though chairman Dean Spanos has yet to send a formal relocation letter to the league or tell authorities in LA and San Diego about the move. Last year, the Rams received approval to move from St. Louis to LA, making them the city's first NFL team in more than 20 years. The Chargers' option to join them is days away from expiry. The Chargers, who spent their first year as a team in LA before moving to San Diego in 1961, are expected to share a stadium being built for the Rams in Inglewood. In San Diego, where the team had long sought a replacement for the aging Qualcomm Stadium, there was disbelief and anger, with a police car posted in front of team headquarters after somebody egged the building. "I am a lifelong Chargers fan," Richard Wade, managing editor of the Bolts from the Blue website, tells the San Diego Union-Tribune. "And as such, I find it incredibly appropriate as well as exceptionally painful that they got my hopes up one last time before dashing them as time was expiring." In November, the city's voters rejected a proposal to raise taxes for a $1.8 billion stadium and convention center project.

levocetirizine ( lcz ) , an active enantiomer of cetirizine , is a second - generation antihistamine that was approved by the us food and drug administration in 2008 for the relief of symptoms associated with allergic diseases in adults and children [ 1 - 3 ] . although it has some side effects such as sleepiness , headache , dry mouth , vision problems , palpitation , and fatigue it is considered to be effective and safe treating allergic disease . we present the first report of lcz - induced liver injury with histologic confirmation in a 48-year - old man without a history of hepatobiliary disease . a 48-year - old man without significant medical history was referred from the dermatology department due to jaundice and generalized pruritus . the patient did not report any fatigue , anorexia , nausea , abdominal discomfort , fever , rash , myalgia , muscle weakness , swelling , and recent illness . medication in recent use included lcz 5 mg daily for 2 months , and the patient had been taking bepotastine besilate 10 mg daily until 2 months ago . he did not report taking any other medications including statins , over - the - counter medications , herbal medications including red ginseng or any extract or nutritional supplements . specific history of exposure to hepatotoxic chemicals or familial history of liver disease was not identified . initial blood pressure was 110/70 mmhg , pulse rate 88/min , respiratory rate 18/min , and body temperature 36.7c . laboratory findings revealed prothrombin time 11.8 s , international normalized ratio 0.88 , aspartate aminotransferase ( ast ) 1,208 iu / l , alanine aminotransferase ( alt ) 2,043 iu / l , total bilirubin 8.68 mg / dl , direct bilirubin 7.23 mg / dl , alkaline phosphatase 184 u / l , lactate dehydrogenase 463 iu / l , protein 5.9 g / dl , albumin 3.9 g / dl , and creatine phosphokinase 21 iu / l . serologic viral marker evaluations revealed hepatitis b surface antigen negative , antibody to hepatitis b surface antigen positive , antibody to hepatitis b core antigen negative , anti - hepatitis c virus negative and anti - human immunodeficiency virus negative . serum anti - mitochondrial antibody , anti - smooth muscle antibody , anti - nuclear antibody , anti - dsdna antibody , anti - neutrophil cytoplasm antibody , and anti - liver kidney microsome antibody were negative . an abdominal sonography revealed no evidence of extrahepatic obstruction , biliary ductal disease , cholelithiasis , or hepatic parenchymal abnormalities . for histologic evaluation , a percutaneous ultrasonography - guided liver biopsy was performed without complications . there was an increased amount of connective tissue extending from the portal area and inflammation around apoptotic hepatocytes ( fig . the patient stopped taking lcz immediately after evaluation and all kinds of liver enzymes were normalized within 3 weeks after discontinuation ( fig . the patient visited the outpatient department several times after discharge and has maintained normal liver function . drug - induced liver injury ( dili ) is a rare but potentially life - threatening adverse drug reaction . a large number of drugs have deleterious effects on the liver , and dili is a major cause of acute liver injury and liver transplantation . dili is responsible for ~10% of all adverse drug reactions in the united states . in korea , the annual extrapolated incidence of dili in hospitalized patients at a university hospital was 12/100,000 persons / year . the mechanism of dili is unknown , but it is not associated with medication dose , particularly idiosyncratic dili . because of its low incidence , idiosyncratic dili can not be detected in preclinical testing or clinical trials . the r - enantiomer of cetirizine dihydrochloride , which has favorable pharmacodynamic and pharmacokinetic characteristics has been demonstrated to be safe and effective for the treatment of allergic diseases , as evidenced by the low number of adverse effects in clinical trials . a similar number of patients reported treatment - emergent adverse events with lcz and placebo . the most common treatment - emergent adverse events are headache ( 4.6% ) , fatigue ( 1.8% ) , and dry throat ( 1.4% ) . one patient in the lcz group showed cellulitis ( 0.4% ) as a serious adverse event . a previous report of lcz - induced hepatitis showed less severe hepatic inflammation compared with our case ( ast 113 iu / ml and alt 115 iu / ml vs. ast 1,208 iu / ml and alt 2,043 iu / ml , respectively ) . this difference of severity was originated in which the previous case was detected by routine liver function test after using lcz only for 2 weeks , but our patient exhibited jaundice after taking lcz for 2 months . because hepatotoxicity is not included in the lcz prescribing information and only one case of lcz - induced liver injury has been reported , hepatotoxicity was not monitored in our case . therefore , any drug could cause dili . patients with dili can present with symptoms similar to those of patients with hepatobiliary disease of other causes , and therefore it is important to maintain a high index of clinical suspicion in determining the diagnosis . the clinical presentations of dili are acute hepatitis and/or cholestasis , although idiosyncratic reactions frequently occur in a background of higher incidence rates of mild asymptomatic liver injury . our patient did not have a specific past medical history , nor show serologic or radiologic findings . based on the timing of lcz administration and the clinical course , we could suspect lcz - induced liver injury . because the patient conducted liver biopsy and recovered after withdrawal of lcz numerous drugs have been reported to cause liver injury , but only one case of lcz - induced liver injury , which lacked histologic confirmation , has been described . furthermore , unlike the previous case of lcz - induced liver injury , our patient showed > 20-fold elevation of serum ast and alt levels . to our knowledge , this is the first reported case of lcz - induced liver injury confirmed by liver biopsy . lcz is generally well tolerated and widely used , and it has consistently demonstrated high response rates and a favorable side - effect profile . although its hepatotoxicity is not established , lcz could be associated with acute liver injury . in conclusion , lcz is an effective and well - tolerated drug for the treatment of allergic diseases ; however , clinicians should be aware of its potential hepatotoxicity .

levocetirizine is a second - generation nonsedative antihistaminic agent that has been demonstrated to be safe and effective for treating allergic disease . there was only one case report of levocetirizine - induced liver toxicity , but a liver biopsy was not performed . in this article , we present the first case of levocetirizine - induced liver injury with histologic findings . a 48-year - old man was hospitalized with jaundice and generalized pruritus that had developed after 2 months of therapy with levocetirizine for prurigo nodularis . laboratory findings revealed acute hepatitis with cholestasis . a liver biopsy demonstrated portal inflammation and hepatitis with apoptotic hepatocytes . the patient fully recovered 3 weeks after withdrawing levocetirizine . although levocetirizine is safe and effective , physicians should be aware of its potential hepatotoxicity .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Small Business Innovation Act of 2013''. SEC. 2. PROGRAM AUTHORIZATION. Section 303(b) of the Small Business Investment Act of 1958 (15 U.S.C. 683(b)) is amended, in the matter preceding paragraph (1), in the first sentence, by inserting after ``issued by such companies'' the following: ``, in a total amount that does not exceed $4,000,000,000 each fiscal year (adjusted annually to reflect increases in the Chained Consumer Price Index for All Urban Consumers (C-CPI-U), as published by the Bureau of Labor Statistics of the Department of Labor)''. SEC. 3. FAMILY OF FUNDS. Section 303(b)(2)(B) of the Small Business Investment Act of 1958 (15 U.S.C. 683(b)(2)(B)) is amended by striking ``$225,000,000'' and inserting ``$350,000,000''. SEC. 4. SMALL BUSINESS EARLY-STAGE INVESTMENT PROGRAM. Title III of the Small Business Investment Act of 1958 (15 U.S.C. 681 et seq.) is amended by adding at the end the following: ``PART D--SMALL BUSINESS EARLY-STAGE INVESTMENT PROGRAM ``SEC. 399A. DEFINITIONS. ``In this part: ``(1) Early-stage small business.--The term `early-stage small business' means a small business concern that-- ``(A) is domiciled in a State or Indian country (as defined in section 1151 of title 18, United States Code); and ``(B) has not generated gross annual sales revenues exceeding $15,000,000 in any of the most recent 3 full years before the date on which the Administrator makes an equity financing to a participating investment company under section 399E. ``(2) Eligible applicant.--The term `eligible applicant' means-- ``(A) an incorporated body, limited liability company, or limited partnership organized and chartered or otherwise existing under Federal or State law for the purpose of performing the functions and conducting the activities contemplated under the program; or ``(B) a manager of a small business investment company. ``(3) Participating investment company.--The term `participating investment company' means an applicant approved under section 399E to participate in the program. ``(4) Program.--The term `program' means the early-stage investment program established under section 399B. ``(5) Small business concern.--The term `small business concern' has the same meaning given that term in section 3(a) of the Small Business Act (15 U.S.C. 632(a)). ``(6) Small business concern in a targeted industry.--The term `small business concern in a targeted industry' means a small business concern that is engaged primarily in researching, developing, manufacturing, producing, or bringing to market goods, products, or services in a targeted industry. ``(7) Targeted industry.--The term `targeted industry' means any of the following business sectors: ``(A) Advanced manufacturing. ``(B) Agricultural technology. ``(C) Biotechnology. ``(D) Clean energy technology. ``(E) Digital media. ``(F) Environmental technology. ``(G) Information technology. ``(H) Life sciences. ``(I) Water technology. ``SEC. 399B. ESTABLISHMENT OF PROGRAM. ``The Administrator shall establish and carry out an early-stage investment program to provide equity financing to support early-stage small businesses in accordance with this part. ``SEC. 399C. ADMINISTRATION OF PROGRAM. ``The Administrator, acting through the Associate Administrator described in section 201, shall administer the program. ``SEC. 399D. APPLICATIONS. ``(a) Requirements for Application.--An application to participate in the program shall include-- ``(1) a business plan describing how the eligible applicant intends to make successful venture capital investments in early-stage small businesses and direct capital to small business concerns in targeted industries or other business sectors; ``(2) information regarding the relevant venture capital investment qualifications and backgrounds of the individuals responsible for the management of the eligible applicant; and ``(3) a description of the extent to which the eligible applicant meets the selection criteria under section 399E. ``(b) Applications From Managers of Small Business Investment Companies.--The Administrator shall establish an abbreviated application process to participate in the program for applicants that are managers of small business investment companies that are licensed under section 301. The abbreviated application process shall incorporate a presumption that managers of small business investment companies that are licensed under section 301 satisfactorily meet the selection criteria under paragraphs (3) and (5) of section 399E(b). ``SEC. 399E. SELECTION OF PARTICIPATING INVESTMENT COMPANIES. ``(a) In General.--Not later than 90 days after the date on which the Administrator receives an application from an eligible applicant under section 399D, the Administrator shall make a determination to conditionally approve or disapprove the eligible applicant to participate in the program and shall transmit the determination to the eligible applicant electronically and in writing. A determination to conditionally approve an eligible applicant shall identify all conditions the eligible applicant is required to satisfy for the Administrator to provide final approval to the eligible applicant to participate in the program, and shall provide a period of not less than 1 year for the eligible applicant to satisfy the conditions. ``(b) Selection Criteria.--In making a determination under subsection (a), the Administrator shall consider-- ``(1) the likelihood that the eligible applicant will meet the goals specified in the business plan of the eligible applicant; ``(2) the likelihood that the investments of the eligible applicant will create or preserve jobs in the United States, both directly and indirectly; ``(3) the character and fitness of the management of the eligible applicant; ``(4) the experience and background of the management of the eligible applicant; ``(5) the extent to which the eligible applicant will concentrate investment activities on early-stage small businesses; ``(6) the likelihood that the eligible applicant will achieve profitability; ``(7) the experience of the management of the eligible applicant with respect to establishing a profitable investment track record; ``(8) the extent to which the eligible applicant will concentrate investment activities on small business concerns in targeted industries; and ``(9) the extent to which the eligible applicant will concentrate investment activities on small business concerns in targeted industries that have received funds from an agency of the Federal Government, including-- ``(A) the National Institutes of Health; ``(B) the National Science Foundation; and ``(C) funds received under the Small Business Innovation Research Program or the Small Business Technology Transfer Program, as such terms are defined under section 9 of the Small Business Act (15 U.S.C. 638). ``(c) Final Approval.-- ``(1) In general.--Not later than 90 days after the date on which an eligible applicant satisfies the conditions identified by the Administrator under subsection (a), the Administrator shall provide final approval to the eligible applicant to participate in the program. ``(2) Exception.--Not later than 30 days after the date on which an eligible applicant, the partnership or management agreement of which conforms to models approved by the Administrator, satisfies the conditions identified by the Administrator under subsection (a), the Administrator shall provide final approval to the eligible applicant to participate in the program. ``(3) Revocation of conditional approval.--If an eligible applicant fails to satisfy the conditions identified by the Administrator under subsection (a) in the time period required by that subsection, the Administrator shall revoke the conditional approval. ``SEC. 399F. EQUITY FINANCINGS. ``(a) In General.--The Administrator may make 1 or more equity financings to a participating investment company. ``(b) Equity Financing Amounts.-- ``(1) Non-federal capital.--An equity financing made to a participating investment company under the program may not be in an amount that exceeds the amount of the capital of the participating investment company that is not from a Federal source and that is available for investment on or before the date on which an equity financing is drawn upon by the participating investment company. The capital of the participating investment company may include legally binding commitments with respect to capital for investment. ``(2) Limitation on aggregate amount.--The aggregate amount of all equity financings made to a participating investment company under the program may not exceed $100,000,000. ``(c) Equity Financing Process.--In making an equity financing under the program, the Administrator shall commit an equity financing amount to a participating investment company, and the amount of each commitment shall remain available to be drawn upon by a participating investment company-- ``(1) for new-named investments, during the 5-year period beginning on the date on which the commitment is first drawn upon by the participating investment company; and ``(2) for follow-on investments and management fees, during the 10-year period beginning on the date on which the commitment is first drawn upon by the participating investment company, with not more than 2 additional 1-year periods available at the discretion of the Administrator. ``(d) Commitment of Funds.--Not later than 2 years after the date on which funds are appropriated for the program, the Administrator shall make commitments for equity financings. ``SEC. 399G. INVESTMENTS IN EARLY-STAGE SMALL BUSINESSES. ``(a) In General.--As a condition of receiving an equity financing under the program, a participating investment company shall make all of the investments of the participating investment company made with amounts received under the program, including securities, promissory notes, or other obligations, in small business concerns, of which at least 50 percent of the total amount of such investments shall be in early-stage small businesses in targeted industries. ``(b) Evaluation of Compliance.--After a participating investment company has expended not less than 50 percent of the amount of an equity financing commitment made under section 399F, the Administrator shall evaluate the compliance of the participating investment company with the requirements under subsection (a). ``(c) Waiver.--The Administrator may waive the requirements for a participating investment company under subsection (a) if the Administrator determines that it is in the best interest of the long term solvency of the fund established in section 399J. ``SEC. 399H. PRO RATA INVESTMENT SHARES. ``Each investment made by a participating investment company under the program shall be treated as comprised of capital from equity financings under the program according to the ratio that capital from equity financings under the program bears to all capital available to the participating investment company for investment. ``SEC. 399I. EQUITY FINANCING INTEREST. ``(a) Equity Financing Interest.-- ``(1) In general.--As a condition of receiving an equity financing under the program, a participating investment company shall convey an equity financing interest to the Administrator in accordance with paragraph (2). ``(2) Effect of conveyance.--The equity financing interest conveyed under paragraph (1)-- ``(A) shall have all the rights and attributes of other investors attributable to their interests in the participating investment company; ``(B) shall not denote control or voting rights to the Administrator; and ``(C) shall entitle the Administrator to a pro rata portion of any distributions made by the participating investment company equal to the percentage of capital in the participating investment company that the equity financing comprises, which shall be made at the same times and in the same amounts as any other investor in the participating investment company with a similar interest. ``(3) Allocations.--A participating investment company shall make allocations of income, gain, loss, deduction, and credit to the Administrator with respect to the equity financing interest as if the Administrator were an investor. ``(b) Manager Profits.--As a condition of receiving an equity financing under the program, the manager profits interest payable to the managers of a participating investment company under the program shall not exceed 20 percent of profits, exclusive of any profits that may accrue as a result of the capital contributions of any such managers with respect to the participating investment company. Any excess of manager profits interest, less taxes payable thereon, shall be returned by the managers and paid to the investors and the Administrator in proportion to the capital contributions and equity financings paid in. No manager profits interest (other than a tax distribution) shall be paid before the repayment to the investors and the Administrator of all contributed capital and equity financings made. ``(c) Distribution Requirements.--As a condition of receiving an equity financing under the program, a participating investment company shall make all distributions to all investors in cash and shall make distributions within a reasonable time after exiting investments, including following a public offering or market sale of underlying investments. ``SEC. 399J. FUND. ``There is established in the Treasury a separate account (in this section referred to as `the fund') for equity financings which shall be available to the Administrator, subject to annual appropriations, as a revolving fund to be used for the purposes of the program. All amounts received by the Administrator under the program, including any moneys, property, or assets derived by the Administrator from operations in connection with the program, shall be deposited in the fund. ``SEC. 399K. APPLICATION OF OTHER SECTIONS. ``To the extent not inconsistent with requirements under this part, the Administrator may apply sections 309, 311, 312, 313, and 314 to activities under this part, and an officer, director, employee, agent, or other participant in a participating investment company shall be subject to the requirements under such sections. ``SEC. 399L. ANNUAL REPORTING. ``The Administrator shall include information on the performance of the program in the annual performance report of the Administration required to be submitted under section 10(a) of the Small Business Act (15 U.S.C. 639(a)).''.

Small Business Innovation Act of 2013 - Amends the Small Business Investment Act of 1958 to authorize the Administrator of the Small Business Administration (SBA) to guarantee the payment of up to $4 billion per fiscal year for debentures or participating securities issued by small business investment companies (SBICs) to encourage the formation and growth of small businesses. Increases from $225 million to $350 million the maximum amount of outstanding leverage for two or more commonly-controlled SBICs. Direct the Administrator to establish and carry out an early-stage investment program to provide, through participating investment companies, equity financing to support early-stage businesses (gross annual sales of $15 million or less in any of the previous three years). Outlines investment company application requirements and selection and approval procedures. Allows the Administrator to make one or more equity financings to a participating company, with a limit of $100 million to any one company. Requires the company to make all of its investments in small businesses, of which at least 50% shall be early-stage small businesses in specified targeted industries. Establishes in the Treasury a separate account for equity financings under the program.

tuberculosis ( tb ) is still an important global health problem ( 12 ) and kills about two million people annually ( 3 ) . tuberculosis is one of major health problems in iran ; however the problem is intensified by immigrants and pilgrims from pakistan and afghanistan . in tb program , cooperation of all health sectors and early diagnosis of disease are the key factors for controlling tb ( 4 ) . based on world health organization ( who ) tb control program , at least 84% of tb smear positives within the society must be diagnosed , 87% of treatments must be successful , and tb incidence must have been reversed by 2015 ( 56 ) . however , it will not be possible to accomplish these goals unless all involved health sectors work together . hence , it is important to evaluate the referral patterns in tuberculosis patients to make further plans and decisions . according to a study , 70% of positive sputum pulmonary tb patients in iran had chosen private doctor s offices as the primary desired clinical unit when their disease started , and 50% of tb patients had been visited at least twice by physicians prior to diagnosis of their disease ( 7 ) . conducting this sort of studies is the first step for planning public - private mix ( ppm ) program . this study can provide information about stakeholders reporting and referring behaviour in tb program for designing the ppm program . this program is proposed by who to strengthen the collaboration of public ( governmental ) sectors and private sectors in the tb program ( 8) . based on mentioned reasons , as designing such a program for surveillance system is one of the priorities of who ( 9 ) , it is not possible to design an appropriate program without a clear knowledge about referral patterns of tb patients . hence , this study assesses the status of referral patterns of patients registered in national tb control program in islamic republic of iran . in this cross sectional study all registered patients from 20 march 2009 to 20 march 2010 ( one year ) in all parts of the country were assessed . tb cases were defined according to who and iran s national tb guideline ( 10 ) . tb suspected patients have been referred from all form of health / treatment systems ( public or private ) to the tb laboratories routinely in iran . laboratory can be public ( health system lab . and reference lab . ) , private or other form ( fig . if tb was proved in suspected patients , it should be reported for registration in the tb program by the physicians or health care workers in any system . then tb reported data was entered in tb register software via double - entry and then data was transferred to province level . person or system that diagnosed tb patients and reported the patients to the tb coordinator physician . public health system was defined as system supported financially by government and it is contains public hospitals ( phs ) and public health outpatient system ( pho ) ; public clinics or health centers . private health system was divided to private hospitals and private outpatient system ( po ) contains private clinics . social security fund system was defined hospitals or clinics that are belong to social security fund organizations . other reporting system contains charity and army forced clinic or hospitals . after a review in provincial level , data was sent to national center of disease control . from all diagnosed patients 147 ( 1.4% ) were wrongly diagnosed as tb patients and were excluded from the study and 10525 tb patients were assessed . the mean of patients age was 47.8 ( 21.6 ) years . from all , 5459 ( 51.9% ) were female , 9032 ( 85.8% ) were iranian , 6985 ( 66.4% ) were urban , 281 ( 2.7% ) were prisoner , and 242 ( 2.3% ) were hiv positive . 5702 patients ( 54.2% ) were smear positive and 9802 ( 93.1% ) were defined as new cases . 3251 ( 30.9% ) all smear positive , 1910 ( 94.2% ) of smear negative and 1810 ( 64.8% ) of extra pulmonary were assessed by laboratory test ( smear , culture or pathology ) . one hundred eighteen ( 5.8% ) of smear negative and 985 ( 35.2% ) of extra pulmonary did not evaluated by any laboratory tests ( smear , culture or pathology ) . totally , 3162 ( 55.5% ) of smear positive tb patients were referred to sputum smear examination in the public health local laboratories and 425 ( 7.5% ) were tested in private laboratories . eight hundred sixty nine ( 42.9% ) of smear negative tb patients were referred to sputum smear examination in the public health local laboratories and 180 ( 8.9% ) in private laboratories . from all smear phs , pho and po reported 4111 ( 39.1% ) , 3007 ( 28.6% ) and 2839 ( 27% ) , respectively ( fig . 2 ) . 1982 ( 48.2% ) of men and 2129 ( 51.8% ) of women patients was reported by phs ( fig . about 80.9% of extra pulmonary and 73.9% of smear negative tb were reported by phs and pho ( fig . all reported smear positive patients , 413 ( 20.4% ) of reported smear negative and 1327 ( 47.5% ) of reported extra pulmonary had at least one laboratory test confirming tb other patients did not have any laboratory test confirmation . all smear positive , 1910 ( 94.2% ) of smear negative and 1810 ( 64.8% ) of extra pulmonary were assessed by laboratory test ( smear , culture or pathology ) . one hundred eighteen ( 5.8% ) of smear negative and 985 ( 35.2% ) of extra pulmonary did not evaluated by any laboratory tests ( smear , culture or pathology ) . totally , 3162 ( 55.5% ) of smear positive tb patients were referred to sputum smear examination in the public health local laboratories and 425 ( 7.5% ) were tested in private laboratories . eight hundred sixty nine ( 42.9% ) of smear negative tb patients were referred to sputum smear examination in the public health local laboratories and 180 ( 8.9% ) in private laboratories . from all smear phs , pho and po reported 4111 ( 39.1% ) , 3007 ( 28.6% ) and 2839 ( 27% ) , respectively ( fig . 2 ) . 1982 ( 48.2% ) of men and 2129 ( 51.8% ) of women patients was reported by phs ( fig . about 80.9% of extra pulmonary and 73.9% of smear negative tb were reported by phs and pho ( fig . all reported smear positive patients , 413 ( 20.4% ) of reported smear negative and 1327 ( 47.5% ) of reported extra pulmonary had at least one laboratory test confirming tb other patients did not have any laboratory test confirmation . based on the results of this study , 14.2% were foreign , 66.4% urban , 2.3% hiv positive . 79.6% of smear negative and 53.5% of extra pulmonary patients were diagnosed clinically ( not laboratory ) . also about one third of the patients had been bedridden in hospitals . except prisons , there was no difference between reporting system regarding gender . typically , 5 to 10% of people exposed to mycobacterium are infected by tb , and usually 70% of infected cases are male ( 11 ) . in other studies it is rarely less than one and usually number of male tb patients is more than female ones ( 1 , 12 ) . such an index is observed in iran , pakistan , afghanistan , and iraq and this ratio is larger than one in other countries . genetic , nutrition , hormones , health inequity and environmental conditions may be among the reasons . the high percentage of tb patients was reported by ph ( outpatient and hospital ) and po system . because of high coverage of health insurance system in our country and even in rural areas , it is quite necessary to involve insurance organizations in tb program . contribution of private sector in diagnosing and reporting tb patients depends on the vast of private sectors and the condition of health system of that country . in other country private system have an important role in tb program ( 1316 ) . in most of countries , the role of private sectors is more significant . as 67.5% of patients in our country prefer to go to private sector when they have illness and tb diagnosis delay is high in these sectors ( 17 ) , it seems that private sector is playing a very important role in tb program but their involvement in reporting smear positive tb is extremely less than ph system . another possible reason is that private physicians work in phs as well . as physicians are working part time in the morning in phs , and as most diagnosed tb patients are bedridden in public hospitals , it is likely that the patients who go to physicians offices will be bedridden in phs . in addition , medical students who will work in private system in the future , learn a little information about tb program . in a study in iran , only 17% of them mentioned smear sputum as a method for tb diagnosis and only 7.5% knew the correct method of tb treatment ( 18 ) . hence , physicians may miss tb patients , therefore it must be seriously considered in tb program and retraining physicians . since physicians work in both systems simultaneously , training in private sector could reinforce ph system as well . also , private laboratories confirm 6.6% of reported tb patients therefore it is important to consider them in tb program . according to non - laboratory conformation of high percentage of smear negative and extra pulmonary tb , it seems that it is essential to train physicians and pathologists in tb program and provide a strong reporting system in pathologic laboratories . in lin et al . study ( 19 ) in taiwan , 22.7% of diagnoses were wrong which is much higher than our study . wrong diagnosis usually happens in extra pulmonary and smear negative cases , therefore , it may be greatly helpful to do tb confirming laboratory test in these cases or some advanced tests like polymerase chain reaction ( pcr ) and adenosine deaminase activity ( ada ) , and in provinces with enough facilities , it is recommended to have private sectors to do this sort of tests . in addition , high percentage of tb patients was reported by hospitals . it seems delay in diagnosis of tb is an important problem in our country . as treatment of tb patients is cost - free in iran and the expenses of hospitalized tb patients are paid by ph system , tb program budget is extremely inadequate . it is necessary to involve other organizations like insurance organizations for founding and education of physician in the tb program . concerning privatization policies within the country , if we do not take required action to empower and include tb program in private sector now , we will face fundamental problems in the future . furthermore , contribution of private sector is needed to achieve specified targets ( 20 ) . it is suggested to implement tb control and reporting system in private sectors in iran and design and perform a public - private mix program . it is essential to make a plan such as public - private mix model in iran . because of high coverage of private physicians in our country and even in rural areas , ethical issues ( including plagiarism , informed consent , misconduct , data fabrication and/or falsification , double publication and/or submission , redundancy , etc ) have been completely observed by the authors .

background : cooperation of all health sectors and early diagnosis of the disease are the key factors for controlling tuberculosis . this study assesses the patterns of reported tuberculosis cases in iran.methods:this was a cross sectional study . tuberculosis cases were defined according to world health organization and iran s national tb guidelines . final data were prepared for analysis using spss16 software.results:public hospitals , public and private outpatient clinics reported 4111 ( 39.1% ) , 3007 ( 28.6% ) and 2839 ( 27% ) cases of tb , respectively . the highest number of reported tb cases was from the public healthcare system . one third of tb cases were reported by private outpatient clinics.conclusion:it is essential to make a plan such as public - private mix model in iran . because of high coverage of private physicians in our country and even in rural areas , it is quite necessary to involve private system in tuberculosis program .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Assuring Honesty and Accountability Act of 2002''. SEC. 2. EXTENSION OF THE DISCRETIONARY SPENDING CAPS. (a) In General.--Section 251(c) of the Balanced Budget and Emergency Deficit Control Act of 1985 is amended-- (1) in paragraph (7) (relating to fiscal year 2003) by redesignation subparagraphs (A), (B), (C), as subparagraphs (C), (D), and (E) respectively, and by inserting before subparagraph (C) (as redesignated) the following: ``(A) for the defense category: $392,742,000,000, in new budget authority and $374,865,000,000 in outlays; ``(B) for the nondefense category: $366,354,000,000, in new budget authority and $406,810,000,000 in outlays;''; (2) in paragraph (8), strike ``(8) with respect to fiscal year 2004'', redesignate the remaining matter as subparagraph (C), and before such redesignated matter insert the following: ``(8) with respect to fiscal year 2004-- ``(A) for the defense category: $400,502,000,000, in new budget authority and $389,942,000,000 in outlays; ``(B) for the nondefense category: $380,305,000,000, in new budget authority and $420,134,000,000 in outlays;''; (3) in paragraph (9), strike ``(9) with respect to fiscal year 2004'', redesignate the remaining matter as subparagraph (C), and before such redesignated matter insert the following: ``(9) with respect to fiscal year 2005-- ``(A) for the defense category: $421,498,000,000, in new budget authority and $408,706,000,000 in outlays; ``(B) for the nondefense category: $387,960,000,000, in new budget authority and $424,854,000,000 in outlays;''; (4) in paragraph (10), strike ``(10) with respect to fiscal year 2006'', redesignate the remaining matter as subparagraph (B), and before such redesignated matter insert the following: ``(10) with respect to fiscal year 2006-- ``(A) for the discretionary category: $837,672,000,000, in new budget authority and $854,020,000,000 in outlays; and (5) redesignate paragraphs (11) through (16) as paragraphs (12) through (17), respectively, and insert after paragraph (10) the following new paragraph: ``(11) with respect to fiscal year 2007, for the discretionary category: $870,178,000,000, in new budget authority and $877,248,000,000 in outlays;''. (b) Expiration.--Section 275 of the Balanced Budget and Emergency Deficit Control Act of 1985 (2 U.S.C. 900 note) is amended by striking subsection (b). SEC. 3. EXTENSION OF PAY-AS-YOU-GO REQUIREMENT. (a) Purpose.--Section 252(a) of the Balanced Budget and Emergency Deficit Control Act of 1985 is amended by striking ``enacted before October 1, 2002,''. (b) Sequestration.--Section 252(b) of the Balanced Budget and Emergency Deficit Control Act of 1985 is amended by striking ``enacted before October 1, 2002''. SEC. 4. AUTOMATIC BUDGET ENFORCEMENT FOR MEASURES CONSIDERED ON THE FLOOR. (a) In General.--Title III of the Congressional Budget Act of 1974 is amended by adding at the end the following new section: ``budget evasion points of order ``Sec. 316. (a) Discretionary Spending Caps.--It shall not be in order in the House of Representatives or the Senate 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 in the House of Representatives or the Senate 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 House of Representatives or 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) Far-Outyears.--It shall not be in order in the House of Representatives or the Senate to consider any bill or resolution (or amendment, motion, or conference report on that bill or resolution) that contains a provision providing new budget authority which reduces revenues which first takes effect after the first 5 fiscal years covered in the most recently adopted concurrent resolution on the budget and that would have the effect of reducing the surplus or increasing the deficit in any fiscal year. ``(e) Enforcement in the House of Representatives.--(1) It shall not be in order in the House of Representatives to consider a rule or order that waives the application of this section. ``(2)(A) This subsection shall apply only to the House of Representatives. ``(B) In order to be cognizable by the Chair, a point of order under this section must specify the precise language on which it is premised. ``(C) As disposition of points of order under this section, the Chair shall put the question of consideration with respect to the proposition that is the subject of the points of order. ``(D) A question of consideration under this section shall be debatable for 10 minutes by each Member initiating a point of order and for 10 minutes by an opponent on each point of order, but shall otherwise be decided without intervening motion except one that the House adjourn or that the Committee of the Whole rise, as the case may be. ``(E) The disposition of the question of consideration under this subsection with respect to a bill or joint resolution shall be considered also to determine the question of consideration under this subsection with respect to an amendment made in order as original text.''. (b) Waiver and Appeal in the Senate.--Section 904 of the Congressional Budget Act of 1974 is amended-- (1) in subsection (c)(1), by inserting ``316,'' after ``313,''; and (2) in subsection (d)(2), by inserting ``316,'' after ``313,''. (c) 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: ``Sec. 316. Budget evasion points of order.''. (d) Reserve Fund for War on Terrorism.--Upon the enactment of any bill or joint resolution that provides new budget authority (and outlays flowing therefrom) for operations of the Department of Defense to prosecute the war on terrorism, the Director of the Office of Management and Budget shall make an appropriate adjustment to the discretionary spending limits (and those limits as adjusted) as set forth in section 251(c) of the Balanced Budget and Emergency Deficit Control Act of 1985 by the amount provided by that measure for that purpose, but the total adjustment for all measures considered under this section shall not exceed $10,000,000,000 in new budget authority for fiscal year 2003 and outlays flowing therefrom. SEC. 5. DISCLOSURE OF INTEREST COSTS. Section 308(a)(1) of the Congressional Budget Act of 1974 (2 U.S.C. 639(a)(1)) is amended-- (1) in subparagraph (B), by striking ``and'' after the semicolon; (2) in subparagraph (C), by striking the period and inserting ``; and''; and (3) by adding at the end the following new subparagraph: ``(D) containing a projection by the Congressional Budget Office of the cost of the debt servicing that would be caused by such measure for such fiscal year (or fiscal years) and each of the 4 ensuing fiscal years.''. SEC. 6. ACCOUNTABILITY IN EMERGENCY SPENDING. (a) OMB Emergency Criteria.--Section 3 of the Congressional Budget and Impoundment Control Act of 1974 is amended by adding at the end the following new paragraph: ``(11)(A) The term `emergency' means a situation that-- ``(i) requires new budget authority and outlays (or new budget authority and the outlays flowing therefrom) for the prevention or mitigation of, or response to, loss of life or property, or a threat to national security; and ``(ii) is unanticipated. ``(B) As used in subparagraph (A), the term `unanticipated' means that the situation is-- ``(i) sudden, which means quickly coming into being or not building up over time; ``(ii) urgent, which means a pressing and compelling need requiring immediate action; ``(iii) unforeseen, which means not predicted or anticipated as an emerging need; and ``(iv) temporary, which means not of a permanent duration.''. (b) Development of Guidelines for Application of Emergency Definition.--Not later than 5 months after the date of enactment of this Act, the chairmen of the Committees on the Budget (in consultation with the President) shall, after consulting with the chairmen of the Committees on Appropriations and applicable authorizing committees of their respective Houses and the Directors of the Congressional Budget Office and the Office of Management and Budget, jointly publish in the Congressional Record guidelines for application of the definition of emergency set forth in section 3(11) of the Congressional Budget and Impoundment Control Act of 1974. (c) Reserve Fund for Emergencies in President's Budget.--Section 1105 of title 31, United States Code is amended by adding at the end the following new subsections: ``(h) The budget transmitted pursuant to subsection (a) for a fiscal year shall include a reserve fund for emergencies. The amount set forth in such fund shall be calculated as provided under section 317(b) of the Congressional Budget Act of 1974. ``(i) In the case of any budget authority requested for an emergency, such submission shall include a detailed justification of the reasons that such emergency is an emergency within the meaning of section 3(11) of the Congressional Budget Act of 1974, consistent with the guidelines described in section 6(b) of the Assuring Honesty and Accountability Act of 2002.''. (d) Separate House Vote on Emergency Designation.--(1) Rule XXII of the Rules of the House of Representatives is amended by adding at the end the following new clause: ``13. In the consideration of any measure for amendment in the Committee of the Whole containing any emergency spending designation, it shall always be in order, unless specifically waived by terms of a rule governing consideration of that measure, to move to strike such emergency spending designation from the portion of the bill then open to amendment.''. (2) The Committee on Rules shall include in the report required by clause 1(d) of rule XI (relating to its activities during the Congress) of the Rules of House of Representatives a separate item identifying all waivers of points of order relating to emergency spending designations, listed by bill or joint resolution number and the subject matter of that measure. (e) Committee Notification of Emergency Legislation.--Whenever the Committee on Appropriations or any other committee of either House (including a committee of conference) reports any bill or joint resolution that provides budget authority for any emergency, the report accompanying that bill or joint resolution (or the joint explanatory statement of managers in the case of a conference report on any such bill or joint resolution) shall identify all provisions that provide budget authority and the outlays flowing therefrom for such emergency and include a statement of the reasons why such budget authority meets the definition of an emergency pursuant to the guidelines described in subsection (b). SEC. 7. APPLICATION OF BUDGET ACT POINTS OF ORDER TO UNREPORTED LEGISLATION. (a) Section 315 of the Congressional Budget Act of 1974 is amended by striking ``reported'' the first place it appears. (b) Section 303(b) of the Congressional Budget Act of 1974 is amended-- (1) in paragraph (1), by striking ``(A)'' and by redesignating subparagraph (B) as paragraph (2) and by striking the semicolon at the end of such new paragraph (2) and inserting a period; and (2) by striking paragraph (3). SEC. 8. BUDGET COMPLIANCE STATEMENTS. Clause 3(d) of rule XIII of the Rules of the House of Representatives is amended by adding at the end the following new subparagraph: ``(4) A budget compliance statement prepared by the chairman of the Committee on the Budget, if timely submitted prior to the filing of the report, which shall include assessment by such chairman as to whether the bill or joint resolution complies with the requirements of sections 302, 303, 306, 311, and 401 of the Congressional Budget Act of 1974 or any other requirements set forth in a concurrent resolution on the budget and may include the budgetary implications of that bill or joint resolution under section 251 or 252 of the Balanced Budget and Emergency Deficit Control Act of 1985, as applicable.''. SEC. 9. JUSTIFICATION FOR BUDGET ACT WAIVERS IN THE HOUSE OF REPRESENTATIVES. Clause 6 of rule XIII of the Rules of the House of Representatives is amended by adding at the end the following new paragraph: ``(h) It shall not be in order to consider any resolution from the Committee on Rules for the consideration of any reported bill or joint resolution which waives section 302, 303, 311, or 401 of the Congressional Budget Act of 1974, unless the report accompanying such resolution includes a description of the provision proposed to be waived, an identification of the section being waived, the reasons why such waiver should be granted, and an estimated cost of the provisions to which the waiver applies.''. SEC. 10. CBO SCORING OF CONFERENCE REPORTS. (a) The first sentence of section 402 of the Congressional Budget Act of 1974 is amended as follows: (1) Insert ``or conference report thereon,'' before ``and submit''. (2) In paragraph (1), strike ``bill or resolution'' and insert ``bill, joint resolution, or conference report''. (3) At the end of paragraph (2) strike ``and'', at the end of paragraph (3) strike the period and insert ``; and'', and after such paragraph (3) add the following new paragraph: ``(4) A determination of whether such bill, joint resolution, or conference report provides direct spending.''. (b) The second sentence of section 402 of the Congressional Budget Act of 1974 is amended by inserting before the period the following: ``, or in the case of a conference report, shall be included in the joint explanatory statement of managers accompanying such conference report if timely submitted before such report is filed''.

Assuring Honesty and Accountability 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 defense and nondefense categories in new budget authority and outlays.Retains (eliminates the expiration of) certain budget enforcement mechanisms.Retains (eliminates the expiration of) pay-as-you-go.Amends the Congressional Budget Act of 1974 concerning legislation which: (1) evades specified budget enforcement mechanisms; (2) provides direct spending (to be included in the Congressional Budget Office (CBO) analysis (scoring); and (3) is unreported by committee (for purposes of budget point of order rules).Limits the adjustment required to the discretionary spending limits in new budget authority for FY 2003 when new budget authority to prosecute the war on terrorism is enacted.Requires reports on legislation which provide new budget, spending, or credit authority or otherwise provide an increase or decrease in revenues or tax expenditures to include a projection by CBO of the cost of debt servicing (interest).Amends the Congressional Budget and Impoundment Control Act of 1974 to address issues of emergency spending through: (1) establishing criteria and guidelines; (2) the inclusion of a reserve fund in the President's Budget; and (3) requiring a separate House vote on an emergency designation.Amends the Rules of the House of Representatives concerning: (1) budget compliance statements (permitting inclusion of budgetary implications); and (2) justification for budget act waivers (inclusion required for bill consideration).

a paraganglioma , or pheochromocytoma , presenting with myocardial infarction ( mi ) is rare . we report a case of a non - hypertensive asymptomatic male without coronary artery disease who presented with an mi likely associated with a paraganglioma causing end organ ischemia . conclusions / summary : uncommon etiologies of mi may be encountered in emergency department ( ed ) settings . a 49-year - old male , parachute instructor by profession , presented to the ed with complaint of non - radiating substernal chest pain following chute deployment . during the episode , he noted associated headache , diaphoresis , and palpitations , which subsequently spontaneously resolved after landing . the parachute jump was described as standard : the patient denied significant environmental conditions , such as a high altitude jump or extreme cold exposure . there was no change in intensity , location , or character of his pain during the remainder of his parachute ride to landing . his pain was described as dull , non - radiating , and rated 7/10 improving to a 5 - 6/10 . no prior history of similar chest pain , associated shortness of breath , nausea , change in sensation , or weakness was reported . the patient did admit to a history of gastroesophageal reflux and was intermittently compliant with his prescribed ranitidine . the patient arrived to the medical center via his private vehicle . upon presentation , the glasgow coma scale ( gcs ) was 15 with pulse of 80 , blood pressure ( bp ) of 132/87 , respirations of 16 , temperature of 100.5 degrees fahrenheit , and room air saturation of 96% . the ed management included sublingual nitroglycerine , which resolved his chest pain after one dose , followed by nitroglycerine paste and aspirin . [ figure 1 ] differential diagnosis included a traumatic aortic dissection , so a cardiac gated computed tomography ( ct ) was obtained that did not demonstrate this etiology as a source for his chest pain . however , an incidental retroperitoneal mass below the level of the left kidney was discovered , which appeared to be highly vascular , with central necrosis , and had at least one feeding artery coming directly off of the aorta [ figure 2 ] . he was started on low weight molecular heparin with clopidogril and admitted for further observation to the cardiac intensive care unit with a planned diagnostic cardiac catheterization . the catheterization showed no angiographic evidence of coronary artery disease ( cad ) and normal left ventricular function . over the course of the hospitalization the patient 's bp was intermittently hypertensive without report of associated chest pain . a neuroendocrine work - up for the para - aortic mass demonstrated a normal catecholamine metabolites , normetanephrine ( 329 mcg/24 hours [ reference range : 88 - 649 mcg/24 hours ] ) and metenephrine ( 164 mcg/24 hours [ reference range : 58 - 203 mcg/24 hours ] ) on 24-hour urine . electrocardiograms ( 1 [ symptomatic ] and 2 [ asymptomatic ] during ed stay ) ct demonstrating para - aortic mass later found to be a paraganglioma the patient was discharged home with atenolol and atorvastatin after a four - day hospitalization . intravenous fluids , phentolamine , and metoprolol were utilized for presurgical treatment in this patient . he returned to his profession as a full - time parachute instructor three months later and subsequently discontinued antihypertensive medications . this case illustrates an unusual cause of mi , rarely reported in the literature.[14 ] extra - adrenal pheochromocytomas , better known as paragangliomas , are neuroendocrine tumors that produce , store , and secrete catecholamines . these neoplasms may occur in all age groups but are most common in young and middle - aged adults . hypertension is the most common sign , and hypertensive paroxysm , or crisis , occurs in more than half of all cases . hypertensive crises may be precipitated by any activity that displaces the abdominal contents , and tachyarrhythmias are the most common cardiac manifestation . angina and acute myocardial infarction may occur in the absence of coronary artery disease due to increased oxygen consumption , coronary spasm , and increased afterload contributing to ischemia . signs and symptoms of paraganglioma / pheochromocytoma diagnosis may be made from elevated plasma catecholamines metabolites , only if drawn during a hypertensive crisis . a 24-hr urine sample may demonstrate increased excretion of metanephrine , normetanephrine , and vanillymandelic acid ( vma ) . treatment of associated hypertension is with phenoxybenzamine , an irreversible alpha - blocker with a long half - life . hypertensive emergencies may be treated with intravenous phentolamine before adequate alpha - blockade is achieved . nitroprusside , calcium channel blockers , and angiotensin - converting - enzyme inhibitor ( ace ) inhibitors will also reduce blood pressure in these patients . five - year survival after surgery is usually over 95% , and the recurrence rate is under 10% . removal of tumor cures hypertension in the majority of patients though residual tumor may cause persistent symptoms . patients with persistent hypertension after tumor resection may be managed with standard anti - hypertensive therapy . primary care follow - up includes 24-hour urine , which should be reassessed annually , even in asymptomatic post - surgical patients . this case shows that cardiac chest pain leading to a myocardial infarction may be the initial manifestation of a paragangliomas in the absence of prior symptoms or significantly elevated blood pressure .

paragangliomas , extra - adrenal pheochromocytomas , are rare and classically associated with sustained or paroxysmal hypertension , headache , perspiration , palpitations , and anxiety . a 49-year - old male , parachute instructor , likely developed a hypertensive emergency when deploying his parachute leading to a myocardial infarction . a para - aortic tumor was incidentally discovered during the patient 's emergency department work - up and was eventually surgically resected . he had no evidence of coronary disease during his evaluation . this case shows that a myocardial infarction may be the initial manifestation of these neuroendocrine tumors . hypertensive emergency , much less elevated blood pressure may not be present at time of presentation .

a large body of literature has come together to form a vision of a different future for cardiovascular risk in the us . ongoing shifts in population demographics , combined with growing , well - established health disparities have changed the dynamics of population - level cardiovascular risk in the us . in the next 35 years , it is predicted that non - hispanic whites will no longer comprise the majority of the us population due to increased numbers of hispanics and asians.1 there are well - established disparities in cardiovascular health outcomes between minority and nonminority groups across the us . understanding varied risk factor profiles and how to treat a changing population are critical to achieving continued improvements in care . such efforts will be key to eliminating racial and ethnic disparities in health and essential to improving population - level cardiovascular care . health disparities in the us exist by ethnicity , race , geography , and socioeconomic status . the overall cost of these disparities in the us has been estimated at around 1.24 trillion us dollars ( table 1 ) . the us office of management and budget has classified minority groups in the us as african american , asian american and pacific islander , native american , white , and hispanic.1 patient , provider , and system - related factors all contribute to racial and ethnic health disparities . at the patient level , individual behaviors ( including diet and exercise ) and potentially genetic factors may contribute to health disparities . at the provider level , factors can include unintentional bias and varying sensitivity to the needs and differences of patients from various backgrounds . at the health systems level , specific factors can include access to care , insurance coverage , cultural competency , and the kinds of infrastructure required to address the needs of diverse clients . unfortunately , there may not be adequate recognition of the issue among doctors ; a large majority of physicians are unlikely to recognize disparities in their own hospital setting or within their own practices.2 physicians are more likely to attribute disparity to patient - level or system - level deficiencies than to problems at the provider level . awareness of potential disparities among clinicians is particularly important because there is a clustering of risk factors that is apparent in minority populations with coronary artery disease ( cad).35 systematically identifying and treating modifiable cardiovascular disease ( cvd ) risk factors is critical to patients in these populations . as noted by kurian and cardarelli , better understanding and awareness of the disparities of cvd risk factors by race and ethnicity may help clinicians and public health professionals develop culturally sensitive interventions , prevention programs , and services specifically targeted toward risk burdens in each of these populations.6 this review will look at identifying the varied cardiovascular risk profile among african americans and hispanic and asian americans in the us . by identifying these differences , they may be better identified and treated , which may lead to the reduction of health disparities . african american subgroups have a greater burden of myocardial infarction ( mi ) , heart failure , stroke , and other cardiovascular events ( table 2).7 on a population level , there is a higher overall prevalence of risk factors that are unrecognized and therefore not treated , which places these individuals at a greater likelihood of experiencing adverse outcomes and therefore potentially higher morbidity and mortality.6,8 among the various minority population groups , african american men have the highest overall death rate from cvd.810 this extends to african american females , whose death rates from cvd are higher than those of white females.9 equally as concerning is the fact that deaths also occur much earlier in african americans compared to whites.10 african american adults have among the highest rates of hypertension in the world.6,8,11 they and mexican americans tend to have higher blood pressure and exhibit lower levels of blood pressure control than whites in the us , even after consideration of modifiable health behaviors , suggesting that other racial / ethnic differences underlie these disparities.12 studies assessing unique characteristics of high blood pressure in african americans have found that aldosterone correlates significantly with several cvd risk factors associated with obesity - related high blood pressure in this population.13 aside from being an independent marker for heart disease morbidity and mortality,14 n - terminal prohormone brain - type natriuretic peptide has been shown to be an independent biomarker for predicting events related to heart disease , including heart failure and overall mortality , in african americans with kidney disease and high blood pressure.15 the pathologic developments accompanying risk factor aggregation contribute to a higher burden of disease among african american men and women . unfortunately , despite having a higher risk burden , african american men and women are less likely to receive adequate treatment or achieve adequate control of these risk factors , including obesity or hypertension.4 african american patients are more likely to have symptoms and functional impairment from acute coronary syndrome ( acs).16 a significantly higher prevalence of coronary heart disease ( chd ) has been identified in elderly african american women.17 presentation of symptoms can vary as well . in a study of women with chd , nearly all minority participants reported a higher sense of fatigue and sleep disturbance as prodromal symptoms , yet fewer than 50% reported prodromal chest pain or discomfort.18 the most commonly identified acute symptom was shortness of breath , with minority women reporting significantly more acute symptoms than white women . in another study of women , african americans demonstrated the highest risk burden , whereas hispanic and alaska native participants showed the least cvd.19 individual and community characteristics explained some racial / ethnic disparities , but other disparities persisted even after controlling for these factors.19 differences exist between the sexes in minority populations as well ; men are more likely to be hospitalized for heart disease and acute mi , while women are more likely to be admitted for congestive heart failure ( chf ) and stroke.8 the death rate from acs is 30% higher among african americans than in non - hispanic whites.3 patients from racial / ethnic minority groups are generally younger , have another comorbidity ( eg , hypertension , diabetes , obesity ) , and are more likely to be women.3,5,20 minority patients with acs are at greater risk of mi , rehospitalization , as well as death from acs and are less likely to receive potentially beneficial treatments such as angiography or percutaneous coronary intervention than nonminority patients.7 population - level data showed that among african american , hispanic , and asian patients who underwent percutaneous coronary intervention , only african americans had a significant reduction in event - free survival 2-years postprocedure.21 it is also noted that african americans with acute mi are younger and are less likely to receive evidenced - based treatments.7 the decreased likelihood of undergoing appropriate treatment , compounded by decreased access to care , may exacerbate disparities in acute mi care.22 african americans are at a significantly higher risk of suffering from heart failure compared with other ethnic groups.23 among chf patients , african americans were least affected by interim mi , while hispanic and white participants were most affected by left ventricular mass increase.23 risk was related to the prevalence of comorbidities with hypertension or diabetes mellitus , which , in combination with environmental factors , may largely explain chf disparity . adjustment for interim infarction accentuates ethnic differences in the incidence of chf between african americans and whites . differential use of coronary revascularization may contribute to the poorer functional outcomes observed among african american patients with documented coronary disease and heart failure.16 in one study of largely african americans with heart failure or left ventricular hypertrophy , those with heart failure shared many abnormalities of systolic , diastolic , and vascular functions with nonfailing left ventricular hypertrophy patients , but had accentuated left ventricular hypertrophy and left atrial dilation or failure . the emergence of data from studies such as the african - american heart failure trial indicates that differences in pharmacology may require tailored drug treatment strategies for people of different racial / ethnic backgrounds with heart failure.24 drugs like isosorbide dinitrate / hydralazine hydrochloride ( fdc i / h ) significantly decreased the risk of all - cause death and first hospitalization for heart failure and improved quality of life , leading to the approval of the first drug tailored for specific racial / ethnic populations.25 african american patients with heart failure who were taking fdc i / h and neurohormonal blockers showed significantly reduced mortality and improvement in event - free survival and hospitalization.25 these factors may help to clarify pathophysiology and better define the african american heart failure population.26 african americans have the highest incidence of stroke among groups in the us ; their strokes tend to be more severe with a higher morbidity and result in higher mortality.27 similar to acs , african americans tend to be younger at the time of the first stroke event . although the overall incidence of stroke in the us appeared to go down in 2010 , the change was the result of a decrease in ischemic stroke in whites only ; the incidence for african americans remained unchanged.28 the high risk factor burden has been implicated as a factor in the higher stroke incidence , particularly the presence of hypertension or diabetes , and especially for african americans.7,28 in one study , african americans had a higher prevalence of five risk factors independently associated with stroke ( treated diabetes , hypertension , peripheral vascular disease , higher c - reactive protein [ crp ] , and inactivity ) , whereas whites had a higher prevalence of three risk factors ( older age , prior mi , and lower high - density lipoprotein [ hdl ] cholesterol).29 awareness of stroke symptoms is suboptimal among minority women , even though they are at higher risk than nonminority women.30 one study noted that african americans with hypertension may have been more aware of their disease status compared to whites , but were less likely to be adequately treated and subsequently have their disease under control.31 this may contribute significantly to the higher incidence of stroke in african americans and should represent a treatment priority in terms of population management . unique among minority groups are hispanic subpopulations , which are linked not just by geographic origin but also by common linguistics , with ancestry related to spanish - speaking nations from europe , central and south america , and the caribbean . hence subgroup analysis , such as comparing mexican american with puerto rican american , may be particularly valid for understanding health outcomes . hispanics have been reported to have higher rates of cvd risk factors yet demonstrate lower rates of chd and total cvd.8,32,33 a difference in risk factors and either prevalence of cvd or subclinical disease have also been seen in mexican americans , though their risk profiles were unique compared to individuals of other hispanic backgrounds , indicating that it is important to delineate hispanic subgroups.34 elevated body mass index ( bmi ) , ranging from obesity to being overweight , has a negative impact on all ages , racial and ethnic groups , and sexes.6,9 diet and exercise , as evidenced by caloric management through proper nutrition as well as the recommended physical activity , also appears to be universally important to health . bmi and waist circumference are inversely associated with fitness , with low fitness most significant in african americans and mexican americans.6,35 for more clearly defined population - level risk factors , the data around obesity remains among the most compelling , with very high rates seen in the us , particularly among hispanic american subgroups , including mexican americans . up to 75% of mexican american men and 72% of mexican american women are obese or overweight . when looking at risk factors such as diabetes , the prevalence of diagnosed diabetes in subgroups such as mexican - americans and puerto ricans was over twice that of non - hispanic whites.14 outside of the environmental impact of lifestyle and behavior on the incidence and prevalence of diabetes in us hispanics , data from 42 extended mexican american families in san antonio , texas , showed that genes accounted for 30% to 45% of the phenotypic prevalence of diabetes . in fact , genes accounted for 15% to 30% of the phenotypic variation in measures of glucose , high blood pressure , and adiposity.36 part of this was due to the unique admixture of us hispanic populations , where a higher degree of native american admixture served as a significant ingredient in the higher rates of type 2 diabetes , with a partial contribution of spanish admixture to diabetes susceptibility among mexico - originating populations . tremendous geographic variation in diabetes manifestation is seen between these populations in the southeastern and southwestern us , respectively , yet no differences among racial / ethnic minority populations were consistently found for many traditional risk factors.6 certain patterns in dyslipidemia have been noted among hispanic populations , with hispanics overall having higher triglyceride levels and lower levels of hdl.34 there are subgroup differences , with mexican americans displaying dyslipidemia patterns seen in diabetics with more elevated small , dense , low - density lipoprotein particles.37 in looking at other nontraditional risk factors , some data suggest that coronary artery calcium is present in lesser amounts in hispanics compared to whites.38,39 the exact impact of this difference in coronary calcium is not well known . in looking at high blood pressure , subgroups such as mexican americans continue to have a higher prevalence of hypertension and prehypertension that non - hispanic whites . puerto rican americans had the highest hypertension - related death rates compared to the other hispanic subgroups , while those of cuban heritage had the lowest overall hypertension - related death rates . an increase in cvd risk factors , specifically hypertension , between first- and second - generation mexican americans suggests that acculturation in terms of diet and lifestyle changes are negatively affecting cvd health in this population.40 there is a lack of data in terms of large studies on heart failure as it relates to us hispanic populations . still , it is believed that the rate of heart failure for hispanics is lower than for african americans but higher than for non - hispanic whites.32 the etiology of heart failure is related not just to hypertension and cad ; there are also data to show that metabolic syndrome and insulin resistance play a more significant role in the pathogenesis of heart failure in us hispanics . mexican americans have the highest rate of age - adjusted prevalence of metabolic syndrome compared to other race / ethnic groups.41 metabolic syndrome has been linked to higher left ventricular mass and dysfunction , independent of blood pressure or underlying cad.42 this may in part explain the differential prevalence and presentation of heart failure among hispanics . looking at population - level data , hispanics in the us undergoing coronary artery bypass graft surgery are generally younger , more likely to be women , and maintain a lower bmi.20,43 one study concludes that some easily measured characteristics can be used to make decisions about allocating resources to case management of hispanic patients with heart disease.44 such case management strategies might emphasize patient education , provider education , decision support , self - management , and in - person care management . there are limited data available on cvd risk factors for asian american subgroups , but traditional cvd risk factors in asian americans have similarities to whites in some instances.45,46 judging by available data , the prevalence of cvd risk factors appears to vary greatly across the asian subgroups , which could affect risk assessment.46 for example , it has been noted that south asians may exhibit more nontraditional cvd risk factors , including differences in inflammatory markers as well as insulin resistance.47 this is noted as well in other populations where markers such as levels of crp vary among racial and ethnic groups . however , despite the ongoing discussions regarding the clinical impact of crp , the meaning behind these differences and how to manage them remain ill defined.42,48 across all minority populations there have been differences in access to screening programs for heart disease ; for example , women and south asians were less likely to undergo systematic screening than white males.49 it has been challenging to appropriately estimate risk in a variety of asian american subgroups due to the lack of data and systematic studies . unfortunately , traditional risk - assessment tools may not be entirely effective ; for example , framingham risk has been demonstrated to systematically overestimate the risk of cad in subgroups like japanese americans.50 by contrast , one study of 4,497 south asians has suggested that adding 10 years to the age of south asian people was the simplest way of calculating coronary heart disease risk using paper - based methods.51 given the overall challenges with traditional risk factors and risk factor tools in appropriately estimating risk , there may be a role for emerging factors such as genetic polymorphism and dysfunctional hdl in assessing risk factors . data from the california health interview survey have provided the most complete picture of smoking prevalence estimates for asian americans and asian - american subgroups.52 korean americans , vietnamese americans , and filipino american males have some of the highest smoking rates , indicating the importance of having targeted interventions to address this cardiovascular risk factor for these subpopulations . acs affects a considerably larger proportion of south asians than individuals from other asian backgrounds.53 significant differences have been noted in the overall risk factor dynamic of south asians compared to non - south asians who have suffered from acute mi compared to other races / ethnicities . yet , despite this higher incidence of acs in the south asian population , the in - hospital case - fatality rate from actual mis is not significantly different across groups.53 it is also very important to look for nontraditional symptoms in certain asian populations , including chinese , south asian , and southeast asian patients , who have been shown to be less likely to exhibit classic symptoms of acute mi.54 southeast asians also suffer from significant delays in recognizing symptoms and appropriate treatment : 30% of this minority group waited longer than 12 hours to seek treatment , whereas nonminorities were more likely to undergo treatment within 3 hours of onset.54 after receipt of revascularization , south asians have been shown to be less likely to experience long - term improvements in angina compared to whites.55 overall , minorities have an elevated risk of morbidity and mortality due to cad56 and have not benefited to the same extent from the general decline in deaths caused by heart disease in the us over the last few decades . population - level efforts to improve lifestyle interventions should be an important part of primary and secondary prevention strategies . although the common wisdom may suggest that such interventions be universally applied , it must be noted that risk assessment is still a challenge in certain populations . for example , current guidelines used to identify metabolic syndrome underestimate the risk in south asian individuals.57 risk algorithms at the population level will need to be continually adjusted to account for these findings so they may more effectively assist in mitigating these disparities . it is essential that health care providers understand the nuances in disease presentation , risk factors , and treatment in different racial and ethnic groups and communities . one strategy will be essential : cultural competency , which has been defined as the ability to provide care to patients with diverse values , beliefs , and behaviors including tailoring delivery of care to meet patients social , cultural , and linguistic needs.58 disparities are best addressed when all aspects of genetics and environment are considered . a recent review on disparities in cardiovascular care found strong evidence for racial disparity in the use of diagnostic cardiac procedures , coronary revascularization , thrombolytic therapy , and other cardiac drug therapies , procedures , and treatments.36 disparities in cad treatment were shown to be at least partially mediated by the ways in which patients races or ethnicity influenced physicians perceptions of patients social and behavioral characteristics.20 awareness of these perceptions as well as differences in incidence , risk factor burdens , prognosis and treatment are necessary to mitigate racial and ethnic disparity . additional research and research strategies in minority communities can provide an opportunity to improve health disparities in cvd . community - based participatory research , as well as intervention strategies that are community - generated , provide a powerful means for developing capacity at the local level . such research can effectively evaluate not just whether a particular strategy worked , but for whom it worked and in what way . collaborative interdisciplinary research offers a lens to see the complex interaction of the multifaceted issues related to health disparities ( eg , personal , provider , and systems levels ) . this type of research , collaborative interdisciplinary research , demands input , coordination , and cooperation at a variety of levels ( from communities to academia ) to identify and implement successful solutions . decreasing health disparities must be a significant goal at the patient , provider , and systems levels.2 although additional research is needed to fully understand the differences in cvd risk , prevention , and treatment to improve outcomes throughout our increasingly diversified population , greater awareness on the parts of practicing physicians is essential . better understanding of the disparities of cvd risk factors may help clinicians and public health professionals develop culturally sensitive interventions , prevention programs , and services specifically targeted at risk burdens in each of these impacted populations.6 burgeoning populations such as hispanics and asians should be incorporated into future research to help us better understand their cvd presentation and optimal interventions . eliminating disparities will require aggressive efforts focused on risk assessment , guideline adherence , and risk - factor control in at - risk populations.4

this is a comprehensive narrative review of the literature on the current science and evidence of population - level differences in risk factors for heart disease among different racial and ethnic population in the us . it begins by discussing the importance of population - level risk assessment of heart disease in light of the growth rate of specific minority populations in the us . it describes the population - level dynamics for racial and ethnic minorities : a higher overall prevalence of risk factors for coronary artery disease that are unrecognized and therefore not treated , which increases their likelihood of experiencing adverse outcomes and , therefore , potentially higher morbidity and mortality . it discusses the rate of acute coronary syndrome ( acs ) in minority communities . minority patients with acs are at greater risk of myocardial infarction , rehospitalization , and death from acs . they also are less likely than nonminority patients to receive potentially beneficial treatments such as angiography or percutaneous coronary intervention . this paper looks at the data surrounding the increased rate of congestive heart failure in racial and ethnic minorities , where the risk is related to the prevalence of comorbidities with hypertension or diabetes mellitus , which , in combination with environmental factors , may largely explain congestive heart failure disparity . the conclusion is it is essential that health care providers understand these various communities , including nuances in disease presentation , risk factors , and treatment among different racial and ethnic groups . awareness of these communities attributes as well as differences in incidence , risk factor burdens , prognosis , and treatment are necessary to mitigate racial and ethnic disparities in heart disease .

smart grid ( sg ) is a modern evolution of the utility electricity delivery system . sg enhances the traditional power grid through computing , communications , networking , and control technologies throughout the processes of electricity generation , transmission , distribution and consumption . the two - way flow of electricity and real - time information is a characteristic feature of sg , which offers many technical benefits and flexibilities to both utility providers and consumers , for balancing supply and demand in a timely fashion and improving energy efficiency and grid stability . according to the us 2009 recovery act @xcite , an sg will replace the traditional system and is expected to save consumer cost and reduce america s dependence on foreign oil . these goals are to be achieved by improving efficiency and spurring the use of renewable energy resources . microgrid ( mg ) is a promising component for future sg deployment . due to the increasing deployment of distributed renewable energy resources ( drers ) , mg provides a localized cluster of renewable energy generation , storage , distribution and local demand , to achieve reliable and effective energy supply with simplified implementation of sg functionalities @xcite . a typical mg architecture is illustrated in fig . [ fig : microgrid ] , consisting of drers ( such as wind turbines and solar photovoltaic cells ) , energy storage systems ( ess ) , a communication network ( e.g. , wireless or powerline communications ) for information delivery , an mg central controller ( mgcc ) , and local residents . the mg has centralized control with the mgcc @xcite , which exchanges information with local residents , ess s , and drers via the information network . there is a single common coupling point with the macrogrid . when disconnected , the mg works in the _ islanded mode _ and drers and ess s provide electricity to local residents . when connected , the mg may purchase extra electricity from the macrogrid or sell excess energy back to the market @xcite . [ ! t ] the balance of electricity demand and supply is one of the most important requirements in mg management . instead of matching supply to demand , smart energy management matches the demand to the available supply using direct load control or off - peak pricing to achieve more efficient capacity utilization @xcite . in this paper , we develop a novel control framework for mg energy management , exploiting the two - way flows of electricity and information . in particular , we consider two types of electricity usage : ( i ) a pre - agreed _ basic usage _ that is `` hard''-guaranteed , such as basic living usage , and ( ii ) extra elastic _ quality usage _ exceeding the pre - agreed level for more comfortable life , such as excessive use of air conditioners or entertainment devices . in practice , residents may set their load priority and preference to obtain the two types of usage @xcite . the basic usage should be always satisfied , while the quality usage is controlled by the mgcc according to the grid status , such as drer generation , ess storage levels and utility prices . the mgcc may _ block _ some quality usage demand if necessary . this can be implemented by incorporating smart meters , smart loads and appliances that can adjust and control their service level through communication flows @xcite . to quantify residents satisfaction level , we define the outage percentage of the quality usage as _ quality of service in electricity _ ( qose ) , which is specified in the service contracts @xcite . the mgcc adaptively schedules electricity to keep the qose below a target level , and accordingly dynamically balance the load demand to match the available supply . in this paper , we investigate the problem of smart energy scheduling by jointly considering renewable energy distribution , ess management , residential demand management , and utility market participation , aiming to minimize the mg operation cost and guarantee the residents qose . the mgcc may serve some quality usage with supplies from the drers , ess s and macrogrid . on the other hand , the mg can also sell excessive electricity back to the macrogrid to compensate for the energy generation cost . the electricity generated from renewable sources is generally random , due to complex weather conditions , while the electricity demand is also random due to the random consumer behavior , and so do the purchasing and selling prices on the utility market . it is challenging to model the random supply , demand , and price processes for mg management , and it may also be costly to have precise , real - time monitoring of the random processes . therefore , a simple , low cost , and optimal electricity scheduling scheme that does not rely on any statistical information of the supply , demand , and price processes would be highly desirable . we tackle the mg electricity scheduling problem with a _ lyapunov optimization _ approach , which is a useful technique to solve stochastic optimization and stability problems @xcite . we first introduce two virtual queues : qose virtual queues and battery virtual queues to transform the qose control problem and battery management problem to queue stability problems . second , we design an adaptive mg electricity scheduling policy based on the lyapunov optimization method and prove several deterministic ( or , `` hard '' ) performance bounds for the proposed algorithm . the algorithm can be implemented _ online _ because it only relies on the current system status , without needing any future knowledge of the energy demand , supply and price processes . the proposed algorithm also converges exponentially due to the nice property of lyapunov stability design @xcite . the algorithm is evaluated with trace - driven simulations and is shown to achieve significant efficiency on mg operation cost while guaranteeing the residents qose . the remainder of this paper is organized as follows . we present the system model and problem formulation in section [ sec : sys ] . an adaptive mg electricity scheduling algorithm is designed and analyzed in section [ sec : policy ] . simulation results are presented and discussed in section [ sec : sim ] . we discuss related work in section [ sec : related ] . section [ sec : con ] concludes the paper . [ ! .notation [ cols="<,<",options="header " , ] we consider the electricity supply and consumption in an mg as shown in fig . [ fig : microgrid ] . we assume that the mg is properly designed such that a portion of the electricity demand related to basic living usage ( e.g. , lighting ) from the residents , termed _ basic usage _ , can be guaranteed by the minimum capacity of the mg . there are randomness in both electricity supply ( e.g. , weather change ) and demand ( e.g. , entertainment usage in weekends ) . to cope with the randomness , the mg works in the _ grid - connected _ mode and is equipped with ess s , such as electrochemical battery , superconducting magnetic energy storage , flywheel energy storage , etc . the ess s store excess electricity for future use . the mgcc collects information about the resident demands , drer supplies , and ess levels through the information network . when a resident demand exceeds the pre - agreed level , a _ quality usage _ request will be triggered and transmitted to the mgcc . the mgcc will then decide the amount of quality usage to be satisfied with energy from the drers , the ess s , or by purchasing electricity from the macrogrid . the mgcc may also decline some quality usage requests . the excess energy can be stored at the ess s or sold back to the macrogrid for compensating the cost of mg operation . without loss of generality , we consider a time - slotted system . the time slot duration is determined by the timescale of the demand and supply processes . the system model is shown in fig . [ fig : system ] . consider a battery farm with @xmath0 independent battery cells , which can be recharged and discharged . we assume that the batteries are not leaky and do not consider the power loss in recharging and discharging , since the amount is usually small . it is easy to relax this assumption by applying a constant percentage on the recharging and discharging processes . for brevity , we also ignore the aging effect of the battery and the maintenance cost , since the cost on the utility market dominates the operation cost of mgs . [ ! t ] let @xmath1 denote the energy level of the the @xmath2th battery in time slot @xmath3 . the capacity of the battery is bounded as @xmath4 where @xmath5 is the maximum capacity , and @xmath6 is the minimum energy level required for battery @xmath2 , which may be set by the battery deep discharge protection settings . the dynamics over time of @xmath1 can be described as @xmath7 where @xmath8 and @xmath9 are the recharging and discharging energy for battery @xmath2 in time slot @xmath3 , respectively . the charging and discharging energy in each time slot are bounded as @xmath10 in each time slot @xmath3 , @xmath8 and @xmath9 are determined such that ( [ eq : batlimit ] ) is satisfied in the next time slot . usually the recharging and discharging operations can not be performed simultaneously , which leads to @xmath11 consider @xmath12 residents in the mg ; each generates basic and quality electricity usage requests , and each can tolerate a prescribed _ outage probability _ @xmath13 for the requested quality usage part . the mgcc adaptively serves quality usage requests at different levels to maintain the qose as well as the stability of the grid . the service of quality usage can be different for different residents , depending on individual service agreements . let @xmath14 be the _ average quality usage arrival rate _ , and @xmath13 a prescribed outage tolerance ( i.e. , a percentage ) for user @xmath15 . the average _ outage rate _ for the quality usage , @xmath16 , should satisfy @xmath17 at each time @xmath3 , the quality usage request from resident @xmath15 is @xmath18 $ ] units , which is an i.i.d random variable with a general distribution and mean @xmath14 . the average rate is @xmath19 according to the law of large numbers . the drers in the mg generate @xmath20 units of electricity in time slot @xmath3 . @xmath20 can offer enough capacity to support the pre - agreed _ basic usage _ in the mg , which is guaranteed by islanded mode mg planning . the electricity is transmitted over power transmission lines . without loss of generality , we assume the power transmission lines are not subject to outages and the transmission loss is negligible . let @xmath21 be the pre - agreed _ basic usage _ for resident @xmath15 in time slot @xmath3 , which can be fully satisfied by @xmath20 , i.e. , @xmath22 , for all @xmath3 . in addition , some _ quality usage _ request @xmath23 may be satisfied if @xmath24 . let @xmath25 be the energy allocated for the quality usage of resident @xmath15 . we have @xmath26 we define a function @xmath27 to indicate the amount of quality usage outage for resident @xmath15 , as @xmath28 . then the average outage rate can be evaluated as @xmath29 . the mgcc may purchase additional energy from the macrogrid or sell some excess energy back to the macrogrid . let @xmath30 $ ] denote the energy purchased from the macrogrid and @xmath31 $ ] the energy sold on the market in time slot @xmath3 , where @xmath32 and @xmath33 are determined by the capacity of the transformers and power transmission lines . since it is not reasonable to purchase and sell energy on the market at the same time , we have the following constraints @xmath34 to balance the supply and demand in the mg , we have @xmath35 the price for purchasing electricity from the macrogrid in time slot @xmath3 is @xmath36 per unit . the purchasing price depends on the utility market state , such as peak / off time of the day . we assume finite @xmath37 $ ] , which is announced by the utility market at the beginning of each time slot and remains constant during the slot period @xcite . unlike prior work @xcite , we do not require any statistic information of the @xmath36 process , except that it is independent to the amount of energy to be purchased in that time slot . if the mgcc determines to sell electric energy on the utility market , the selling price from the market broker is denoted by @xmath38 $ ] in time slot @xmath3 , which is also a stochastic process with a general distribution . we also assume @xmath39 is known at the beginning of each time slot and independent to the amount of energy to be sold on the market . we assume @xmath40 , @xmath41 and @xmath42 for all @xmath3 . that is , the mg can not make profit by greedily purchasing energy from the market and then sell it back to the market at a higher price simultaneously . given the above models , a control policy @xmath43 is designed to minimize the operation cost of the mg and guarantee the qose of the residents . we formulate the electricity scheduling problem as @xmath44 problem ( [ eq : obj ] ) is a stochastic programming problem , where the utility prices , generation of drers , and consumption of residents are all random . the solution also depends on the evolution of battery states . it is challenging since the supply , demand , and price are all general processes . we first adopt a _ battery virtual queue _ @xmath45 that tracks the charge level of each battery @xmath2 : @xmath46 where @xmath47 is a constant for the trade - off between system performance and ensuring the battery constraints . this constant @xmath48 is carefully selected to ensure the evolution of the battery levels always satisfy the battery constraints ( [ eq : batlimit ] ) , which will be examined in section [ subsec : perf ] . the virtual queue can be deemed as a shifted version of the battery dynamics in ( [ eq : batdyn ] ) as @xmath49 these queues are `` virtual '' because they are maintained by the mgcc control algorithm . unlike an actual queue , the virtual queue backlog @xmath45 may take negative values . we next introduce a conceptual _ qose virtual queue _ @xmath50 , whose dynamics are governed by the system equation as @xmath51^+ + i_n(t ) , \;\ ; \forall \ ; n , t.\ ] ] where @xmath52^+ = \max\{0 , x\}$ ] . [ propo : vqueue ] if an mgcc control policy stabilizes the qose virtual queue @xmath50 , the outage quality usage of resident @xmath15 will be stabilized at the average qose rate @xmath53 . according to the system equation ( [ eq : vqueue ] ) , we have @xmath54 summing up the inequalities in ( [ eq : list ] ) , we have @xmath55 dividing both sides by @xmath3 and letting @xmath3 go to infinity , we have @xmath56 . \nonumber\end{aligned}\ ] ] note that @xmath57 is finite . if @xmath50 is rate stable by a control policy @xmath58 , it is finite for all @xmath3 . we have @xmath59 , which yields @xmath60 due to the definitions of @xmath14 and @xmath58 . with theorem [ propo : vqueue ] , we can transform the original problem ( [ eq : obj ] ) into a queue stability problem with respect to the qose virtual queue and the battery virtual queues , which leads to a system stability design from the control theoretic point of view . we have a reformulated stochastic programming problem as follows . @xmath61 theorem [ propo : vqueue ] indicates that qose provisioning is equivalent to stabilizing the qose virtual queue @xmath50 , while stabilizing the virtual queues ( [ eq : virtualbat ] ) ensures that the battery constraints ( [ eq : batlimit ] ) are satisfied . we then apply _ lyapunov optimization _ to develop an adaptive electricity scheduling policy for problem ( [ eq : qobj ] ) , in which the policy greedily minimize the lyapunov drift in every slot @xmath3 to push the system toward stability . we define the _ lyapunov function _ for system state @xmath62^t$ ] with dimension @xmath63 as follows , in which @xmath64^t$ ] and @xmath65^t$ ] . @xmath66 ^ 2 + \frac{1}{2 } \sum_{n=1}^n\left [ z_n(t)\right]^2,\ ] ] which is positive definite , since @xmath67 when @xmath68 and @xmath69 . we then define the conditional one slot _ lyapunov drift _ as @xmath70 with the drift defined as in ( [ eq : driftdef ] ) , it can be shown that @xmath71 + \right . \nonumber\\ & & \hspace*{0.35 in } \left . \sum_{n=1}^n [ ( z_n(t+1))^2 - ( z_n(t))^2 | z_n(t ) ] \right\}\nonumber\\ & \leq & b+\sum_{n=1}^n\mathbb{e}\{z_n(t)(1-\delta_n)\alpha_n(t)|z_n(t)\ } + \nonumber\\ & & \sum_{k=1}^k\mathbb{e}\{x_k(t)(r_k(t ) - d_k(t))|x_k(t)\ } - \nonumber \\ & & \sum_{n=1}^n\mathbb{e}\{(z_n(t ) + \alpha_n(t))p_n(t)|z_n(t)\ } , \label{eq : drift}\end{aligned}\ ] ] where @xmath72 is a constant . the derivation of ( [ eq : drift ] ) is given in appendix [ app : drift ] . to minimize the operation cost of the mg , we adopt the _ drift - plus - penalty method _ @xcite . specifically , we select the control policy @xmath73 to minimize the bound on the drift - plus - penalty as : @xmath74 where @xmath75 is defined in section [ subsubsec : vqs ] for the trade - off between stability performance and operation cost minimization . given the current virtual queue states @xmath45 and @xmath50 , market prices @xmath76 and @xmath39 , available drers energy @xmath77 , and the resident quality usage request @xmath23 , the optimal policy is the solution to the following problem . @xmath78 + \nonumber\\ & & v[q(t)c(t ) - s(t)w(t ) ] + \nonumber\\ & & \sum_{k=1}^k [ x_k(t)(r_k(t ) - d_k(t ) ) ] - \nonumber \\ & & \sum_{n=1}^n [ ( z_n(t ) + \alpha_n(t))p_n(t ) ] \\ \mbox{s.t . } & & \mbox{~(\ref{eq : chadischa } ) , ( \ref{eq : batredecontr } ) , ( \ref{eq : resbal } ) , ( \ref{eq : sellconst } ) , ( \ref{eq : mgbal } ) } . \nonumber \end{aligned}\ ] ] since the control policy @xmath79 is only applied to the last three terms of ( [ eq : objdriftfull ] ) , we can further simplify problem ( [ eq : objdriftfull ] ) as @xmath80 + \sum_{k=1}^k \left [ x_k(t)(r_k(t ) - \right . \nonumber\\ & & \hspace{-0.2 in } \left . d_k(t ) ) \right ] - \sum_{n=1}^n [ ( z_n(t ) + \alpha_n(t))p_n(t ) ] \\ \mbox{s.t . } & & \hspace{-0.2 in } \mbox{~(\ref{eq : chadischa } ) , ( \ref{eq : batredecontr } ) , ( \ref{eq : resbal } ) , ( \ref{eq : sellconst } ) , ( \ref{eq : mgbal } ) } , \nonumber \end{aligned}\ ] ] which can be solved based on observations of the current system state @xmath81 . with the lyapunov penalty - and - drift method , we transform problem ( [ eq : qobj ] ) to problem ( [ eq : objdrift ] ) to be solved for each time slot . the solution only depends on the current system state ; there is no need for the statistics of the supply , demand and price processes and no need for any future information . the solution algorithm to this problem is thus an _ online algorithm_. we have the following properties for the optimal scheduling . [ lm : lm1 ] the optimal solution to problem ( [ eq : objdrift ] ) has the following properties : 1 . if @xmath82 , we have @xmath83 , 1 . if @xmath84 , the optimal solution always selects @xmath85 ; if @xmath86 , the optimal solution always selects @xmath87 . [ item : item1a ] 2 . if @xmath88 , the optimal solution always selects @xmath89 ; if @xmath90 , the optimal solution always selects @xmath91 . [ item : item1b ] 2 . when @xmath92 , we have @xmath93 , [ enu : enu2 ] 1 . if @xmath94 , the optimal solution always selects @xmath85 ; if @xmath95 , the optimal solution always selects @xmath87 . if @xmath96 , the optimal solution always selects @xmath89 ; if @xmath97 , the optimal solution always selects @xmath91 . the proof of lemma [ lm : lm1 ] is given in appendix [ app : lm1 ] . [ lm : lm2 ] the optimal solution to the battery management problem has the following properties : 1 . if @xmath98 , the optimal solution always selects @xmath85 . 2 . if @xmath99 , the optimal solution always selects @xmath87 . the proof of lemma [ lm : lm2 ] is given in appendix [ app : lm2 ] . [ lm : lm3 ] the optimal solution to the qose provisioning problem has the following properties : 1 . if @xmath100 , the optimal solution always selects @xmath89 . 2 . if @xmath101 , the optimal solution always selects @xmath91 . the proof directly follows lemma [ lm : lm1 ] and is similar to the proof of lemma [ lm : lm2 ] . we omit the details for brevity . lemma [ lm : lm1 ] provides useful insights for simplifying the algorithm design , which will be discussed in section [ subsec : alg ] . the intuition behind these lemmas is two - fold . on the ess management side , if either the purchasing price @xmath36 or the selling price @xmath39 is low , the mg prefers to recharge the ess s to store excess electricity for future use . on the other hand , if either @xmath36 or @xmath39 is high , the mg is more likely to discharge the ess s to reduce the amount of energy to purchase or sell more stored energy back to the macrogrid . on the qose provisioning side , if either @xmath36 or @xmath39 is high and the quality usage @xmath23 is low , the mg is apt to decline the quality usage for lower operation cost . on the other hand , if either @xmath36 or @xmath39 is low and @xmath23 is high , the quality usage are more likely to be granted by purchasing more energy or limiting the sell of energy . in this section , we present the mg control policy @xmath79 to solve problem ( [ eq : objdrift ] ) . given the current virtual queue state @xmath102 , market prices @xmath36 and @xmath39 , quality usage @xmath23 and available energy @xmath77 from the drers for serving quality usage , problem ( [ eq : objdrift ] ) can be decomposed into the following two linear programming ( lp ) sub - problems ( since one of @xmath76 and @xmath103 must be zero , see ( [ eq : sellconst ] ) ) . @xmath104 -\nonumber\\ & & \hspace{-0.25 in } \sum_{n=1}^n((z_n(t ) + \alpha_n(t))p_n(t ) ) \\ \hspace{-0.1 in } \mbox{s.t . } & & \hspace{-0.25 in } s(t ) = 0 , \mbox{(\ref{eq : chadischa } ) , ( \ref{eq : batredecontr } ) , ( \ref{eq : resbal } ) , ( \ref{eq : mgbal } ) . } \nonumber\end{aligned}\ ] ] @xmath105 -\nonumber\\ & & \hspace{-0.25 in } \sum_{n=1}^n((z_n(t ) + \alpha_n(t))p_n(t ) ) \\ \hspace{-0.1 in } \mbox{s.t.~ } & & \hspace{-0.25 in } q(t ) = 0 , \mbox{(\ref{eq : chadischa } ) , ( \ref{eq : batredecontr } ) , ( \ref{eq : resbal } ) , ( \ref{eq : mgbal } ) . } \nonumber\end{aligned}\ ] ] in sub - problem ( [ eq : objdriftsub1 ] ) , we set @xmath85 if @xmath84 , and @xmath87 if @xmath86 according to lemma [ lm : lm1 ] . also , if @xmath90 , we set @xmath91 ; otherwise , we reset constraint ( [ eq : resbal ] ) to a smaller search space of @xmath106 . we take a similar approach for solving sub - problem ( [ eq : objdriftsub2 ] ) by replacing @xmath36 with @xmath39 . then we compare the objective values of the two sub - problems and select the more competitive solution as the mg control policy . the complete algorithm is presented in algorithm [ tab : algorithm ] . [ ! t ] mgcc initializes the qose target to @xmath13 and the virtual queues backlogs @xmath50 and @xmath45 , for all @xmath15 and @xmath2 the proposed scheduling algorithm dynamically balances cost minimization and qose provisioning . it only requires current system state information ( i.e. , as an online algorithm ) and requires no statistic information about the random supply , demand , and price processes . the algorithm is also robust to non - i.i.d . and non - ergodic behaviors of the processes @xcite . [ propo : battery ] the constraint on the ess battery level @xmath1 , @xmath107 , is always satisfied for all @xmath2 and @xmath3 . from the battery virtual queue definition ( [ eq : batteryque ] ) , the constraint @xmath107 is equivalent to @xmath108 we assume all the batteries satisfy the battery capacity constraint at the initial time @xmath109 , i.e. , @xmath110 , for all @xmath2 . supposing the inequalities hold true for time @xmath3 , we then show the inequalities still hold true for time @xmath111 . first , we show @xmath112 . if @xmath113 , then with @xmath114 from lemma [ lm : lm2 ] , we have @xmath115 . if @xmath116 , then the largest value is @xmath117 . for any @xmath75 @xmath118 it follows that @xmath112 . next , we show @xmath119 . assuming @xmath120 , then from lemma [ lm : lm2 ] , we have @xmath121 . it follows that @xmath122 if @xmath123 , following ( [ eq : batteryque ] ) , we have @xmath124 therefore , we have @xmath119 . thus the inequalities also hold true for time @xmath111 . it follows that @xmath107 is satisfied under the optimal scheduling algorithm for all @xmath2 , @xmath3 . [ propo : qoubound ] the worst - case backlogs of the qose virtual queue for each resident @xmath15 is bounded by @xmath125 , for all @xmath15 , @xmath3 . moreover , the worst - case average amount of outage of quality usage for resident @xmath15 in a period @xmath126 is upper bounded by @xmath127 . \(i ) we first prove the upper bound @xmath128 . initially , we have @xmath129 . assume that in time slot @xmath3 the backlog of the qose virtual queue of resident @xmath15 satisfies @xmath125 . we then check the backlog at time @xmath111 and show the bound still holds true . if @xmath100 , following lemma [ lm : lm3 ] , the optimal scheduling for the quality usage of resident @xmath15 satisfies @xmath89 . from the virtual queue dynamics ( [ eq : vqueue ] ) , we have @xmath130^+ + \delta_n\alpha_n(t ) . \nonumber\end{aligned}\ ] ] if @xmath131 , we have @xmath132 ; otherwise , it follows that @xmath133 . if @xmath134 , we have @xmath135^+ + \alpha_n^{max}$ ] . if @xmath131 , we have @xmath136 ; otherwise , we have @xmath137 . thus we have @xmath138 . the proof of the qose virtual queue backlog bound is completed . \(ii ) consider an interval @xmath139 $ ] with length of @xmath126 . summing ( [ eq : vqueue ] ) from @xmath140 to @xmath141 , we have @xmath142 \geq \sum_{\tau = t_1}^{t_2}[\alpha_n(\tau)-p_n(\tau ) ] - t \delta_n \alpha_n^{max}$ ] . it follows that @xmath143 \leq z_n^{max } + t\delta_n\alpha_n^{max}.\ ] ] [ propo : objbound ] the average mg operation cost under the adaptive electricity scheduling algorithm in algorithm[tab : algorithm ] , @xmath144 , is bounded as @xmath145 , where @xmath146 is optimal operating cost and @xmath147 . from theorem [ propo : battery ] , the battery capacity constraints is met in each time slot with the adaptive control policy . take expectation on ( [ eq : batdyn ] ) and sum it over the period @xmath148 $ ] : @xmath149 , \ ; \forall \ ; k.\ ] ] since @xmath150 , we divide both sides by @xmath3 and let @xmath3 go to infinity , to obtain @xmath151 consider the the following relaxed version of problem ( [ eq : obj ] ) . @xmath152 since the constraints in problem ( [ eq : relaxobj ] ) are relaxed from that in problem ( [ eq : obj ] ) , the optimal solution to problem ( [ eq : obj ] ) is also feasible for problem ( [ eq : relaxobj ] ) . the solution of ( [ eq : relaxobj ] ) does not depend on battery energy levels . let the optimal solution for problem ( [ eq : relaxobj ] ) be @xmath153 and the corresponding object value is @xmath154 . according to the properties of optimality of stationary and randomized policies @xcite , the optimal solution @xmath155 satisfies @xmath156 and @xmath157 . we substitute solution @xmath155 into the right - hand - side of the drift - and - penalty ( [ eq : driftpen ] ) . since our proposed policy minimizes the right - hand - side of ( [ eq : driftpen ] ) , we have @xmath158 the second inequality is due to @xmath156 , @xmath159 , @xmath160 , @xmath161 , and @xmath154 . taking expectation and sum up from @xmath162 to @xmath163 , we obtain @xmath164 the second inequality is due to the nonnegative property of lyapunove functions . divide both sides by @xmath165 and let @xmath126 go to infinity . since the initial system state @xmath166 is finite , we have @xmath167 . it is worth noting that the choice of @xmath168 controls the optimality of the proposed algorithm . specifically , a larger @xmath168 leads to a tighter optimality gap . however , from the proof of theorem [ propo : battery ] , @xmath168 is limited by @xmath48 , which ensures the feasibility of the battery constraints . this is actually a similar phenomenon to the so - called _ performance - congestion trade - off _ @xcite . through the definition of @xmath48 ( see section [ subsubsec : vqs ] ) , it can be seen that if we invest more on the individual storage components for a larger ess capacity , the proposed algorithm can achieve a better performance ( i.e. , a smaller optimality gap ) . it is also worth noting that all the performance bounds of the proposed algorithm are deterministic , which provide `` hard '' guarantees for the performance of the proposed adaptive scheduling policy in every time slot . unlike probabilistic approaches , the proposed method provides useful guidelines for the mg design , while guaranteeing the mg operation cost , grid stability , and the usage quality of residents . we demonstrate the performance of the proposed adaptive mg electricity scheduling algorithm through extensive simulations . we simulated an mg with @xmath169 residents , where the electricity from drers is supplied by a wind turbine plant . we use the renewable energy supply data from the western wind resources dataset published by the national renewable energy laboratory @xcite . the ess s consists of @xmath170 phev li - ion battery packs , each of which has a maximum capacity of @xmath171 kwh and the minimum energy level is @xmath162 . the battery can be fully charged or discharged within @xmath172 hours @xcite . the residents pre - agreed power demand is uniformly distributed in [ @xmath172 kw , @xmath173 kw ] , and the quality usage power is uniformly distributed in [ @xmath162 , @xmath174 kw ] . the mg works in the grid - connected mode and may purchase / sell electricity from / to the macrogrid . the utility prices in the macrogrid are obtained from @xcite and are time - varying . we assume the sell price by the broker is random and below the purchasing price in each time slot . the time slot duration is @xmath175 minutes . the mgcc serves a certain level of quality usage according to the adaptive electricity scheduling policy . the qose target is set to @xmath176 for all residents . the control parameter is @xmath177 , unless otherwise specified . we first investigate the average qoses and total mg operation cost with default settings for a five - day period . we use matlab lp solver for solving the sub - problems ( [ eq : objdriftsub1 ] ) and ( [ eq : objdriftsub2 ] ) . for better illustration , we only show the qoses of three randomly chosen users in fig . [ fig : vmaxqou ] . it can be seen that all the average qoses converge to the neighborhood of @xmath178 within @xmath179 slots , which is close to the mg requested criteria @xmath180 . in fact the proposed scheme converges exponentially , due to the inherent exponential convergence property in lyapunov stability based design @xcite . [ fig : hetroqou ] we also plot the mg operation traces from this simulation in fig . [ fig : vmaxele ] . the energy for serving quality usage from the deres are plotted in fig . [ fig : vmaxele](a ) . it can be seen that the drers generate excessive electricity from slot @xmath181 to @xmath179 , which is more than enough for the residents . thus , the mgcc sells more electricity back to the macrogrid and obtains significant cost compensation accordingly . in fig . [ fig : vmaxele](b ) , we plot the traces of electricity trading , where the positive values are the purchased electricity ( marked as brown bars ) , and the negative values represent the sold electricity ( marked as dark blue bars ) . the mg operation costs are plotted in fig . [ fig : vmaxele](c ) . the curve rises when the mg purchases electricity and falls when the mg sells electricity . from slot @xmath181 to @xmath179 , the operation cost drops significantly due to profits of selling excess electricity from the deres . the operation cost is @xmath182 by the end of the period , which means the net spending of the mg is @xmath182 on the utility market . we then examine the energy levels of the batteries in fig . [ fig : vmaxbat ] . we only plot the levels of three batteries in the first @xmath183 time slots for clarity . the proposed control policy charges and discharges the batteries in the range of @xmath162 to @xmath171 kwh , which falls strictly within the battery capacity limit . it can be seen that the amount of energy for charging or discharging in one slot is limited by @xmath172 kwh in the figure , due to the short time slots comparing to the @xmath172-hour fully charge / discharge periods . for longer time slot durations and batteries with faster charge / discharge speeds , the variation of the energy level in fig . [ fig : vmaxbat ] could be higher . however , theorem [ propo : battery ] indicates that the feasibility of the battery management constraint is always ensured , if the control parameter @xmath168 satisfies @xmath75 . we next evaluate the performance of the proposed adaptive control algorithm under different values of control parameter @xmath168 . for different values @xmath184 , the qoses are stabilized at @xmath185 , @xmath186 , and @xmath187 , and the total operation cost are $ @xmath188 , $ @xmath189 , and $ @xmath190 , respectively . we find the qose decreases from @xmath185 to @xmath187 , while the total operation cost is increased from $ @xmath188 to $ @xmath190 , as @xmath48 is decreased . this demonstrates the performance - congestion trade - off as in theorem [ propo : objbound ] : a larger @xmath168 leads to a smaller objective value ( i.e. , the operating cost ) , but the system is also penalized by a larger virtual queue backlog , which corresponds to a higher qose . on the contrary , a smaller @xmath168 favors the resident quality usage , but increases the total operation cost . in practice , we can select a proper value for this parameter based on the mg design specifications . it would be interesting to examine the case where the residents require different qoses . we assume @xmath191 residents with a service contract for lower qoses . we plot the average qoses of three residents with @xmath192 in fig . [ fig : hetroqou ] . resident @xmath193 prefers an outage probability @xmath194 , while residents @xmath172 and @xmath195 require an outage probability @xmath196 . it can be seen in fig . [ fig : hetroqou ] that resident @xmath193 s qose converges to @xmath197 , while the other two residents qoses remains around @xmath198 . we compare the performance of the proposed scheme with a heuristic mg electricity control policy ( mecp ) , which serves as a benchmark . in mecp , the mgcc blocks quality usage requests simply by tossing a coin with the target probability . we use @xmath199 in the following simulations . if there is sufficient electricity from the drers , all the quality usage requests will be granted and the excess energy will be stored in the ess s . if there is still any surplus energy , the mgcc will sell it to the macrogrid . if there is insufficient electricity from the drers , the ess s will be discharged to serve the quality usage requests . the mgcc will purchase electricity from the macrogrid if even more electricity is required . finally , with a predefined probability , e.g. , @xmath200 in the following simulation , the mg purchases as much energy as possible to charge the ess s . we run @xmath170 simulations with different random seeds for a seven - day period . we assume in the first five days the resident behavior is the same as previous default settings . in the last two days , we assume the residents are apt to request more electricity ( e.g. , more activities in weekends ) we assume in the last two days the resident pre - agreed basic usage power demand is uniformly distributed from @xmath191 kw to @xmath201 kw . the quality usage power is uniformly distributed from @xmath162 to @xmath202 kw . we find that the proposed algorithm earns @xmath203 from the utility market ( with @xmath204 confidence interval @xmath205 $ ] ) . the profit mainly comes from the abundant drer generation in the last two days , as shown in fig . [ fig : costcisingle ] . mecp only earns @xmath206 from the market ( with @xmath204 confidence interval @xmath207 $ ] ) , which is @xmath208 lower than that of the proposed control policy . we also find that the qoses under the proposed control policy remains about @xmath209 , which is lower than the criteria @xmath199 . this is because there are a sudden price jump from @xmath210/mwh to @xmath211/mwh in the afternoon of the last day . this sharp increment increases @xmath212 eight times and decreases the value of @xmath48 . due to the performance - congestion trade - off , the qoses become smaller ( lower than mecp s @xmath213 level ) . [ ! t ] -day period.,title="fig:",width=326,height=364 ] [ ! t ] -day period.,title="fig:",width=326,height=364 ] sg is regarded as the next generation power grid with two - way flows of electricity and information . several comprehensive reviews of sg technologies can be found in @xcite . recently , sg research is attracting considerable interest from the networking and communications communities @xcite . for example , the design of wireless communication systems in sg is studied in @xcite . the authors of @xcite explore the important wireless communication security issues in smart grid . the energy management and power flow control in the grid is investigated in @xcite to reach system - wide reliability under uncertainties . the frequency oscillation in power networks is studied in @xcite by epidemic propagation and a social network based approach . the electric power management with phevs are examined in @xcite . microgrid is a new grid structure to group drers and local residents loads , which provides a promising way for the future sg . in @xcite , the authors review the mg structure with distributed energy resources . in @xcite , the integration of random wind power generation into grids for cost effective operation is investigated . in @xcite , the authors propose a useful online method to discover all available drers within the islanded mode mircogrid and compute a drer access strategy . the problem of optimal residential demand management is studied in @xcite , aiming to adapt to time - varying energy generation and prices , and maximize user benefit . in @xcite , the authors investigate energy storage management with a dynamic programming approach . the size of the ess s for mg energy storage is explored in @xcite . lyapunov optimization is a useful stochastic optimization method @xcite . it integrates the lyapunov stability concept of control theory with optimization and provides an efficient framework for solving schedule and control problems . it has been widely used and extended in the communications and networking areas @xcite . in two recent work @xcite , the lyapunov optimization method is applied to jointly optimize power procurement and dynamic pricing . in @xcite , the authors investigate the problem of profit maximization for delay tolerant consumers . in @xcite , the authors study electricity storage management for data centers , aiming to meet the workload requirement . both of the work are designed based on a _ single _ energy consumption entity model . in this paper , we developed an online adaptive electricity scheduling algorithm for smart energy management in mgs by jointly considering renewable energy penertration , ess management , residential demand management , and utility market participation . we introduced a qose model by taking into account minimization of the mg operation cost , while maintaining the outage probabilities of resident quality usage . we transformed the qose control problem and ess management problem into queue stability problems by introducing the qose virtual queues and battery virtual queues . the lyapunov optimization method was applied to solve the problem with an efficient online electricity scheduling algorithm , which has deterministic performance bounds . our simulation study validated the superior performance of the proposed approach . this work is supported in part by the us national science foundation ( nsf ) under grants cns-0953513 . any opinions , findings , and conclusions or recommendations expressed in this material are those of the author(s ) and do not necessarily reflect the views of the foundation . 10 [ 1]#1 url@samestyle [ 2]#2 [ 2]l@#1=l@#1#2 y. huang , s. mao , and r. m. nelms , `` adaptive electricity scheduling in microgrids , '' in _ proc . ieee infocom13 _ , turin , italy , apr . 2013 , pp . 19 . whitehouse.gov , `` battery and electric vehicle report , '' jul . 2010 , [ online ] available : http://www.whitehouse.gov/files/documents/battery-and-electric-vehicle-report-final.pdf . x. fang , s. misra , g. xue , and d. yang , `` smart grid - 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( z_n(t))^2 | z_n(t ) ] \right\}\nonumber\ ] ] @xmath214 \right\ } + \frac{1}{2 } \mathbb{e } \left\{\sum_{n=1}^n \left [ i_n(t)^2 + \right . \nonumber \\ & & \hspace*{-0.6 in } ( \delta_n\alpha_n(t))^2 + 2z_n(t)(i_n(t ) - \delta_n\alpha_n(t))|z_n(t)\}\nonumber\ ] ] @xmath215\ } + \nonumber \\ & & \hspace*{-0.6 in } \sum_{k=1}^k \mathbb{e}\{x_k(t)(r_k(t ) - d_k(t))|x_k(t)\ } + \nonumber \ ] ] @xmath216\ } + \nonumber\\ & & \hspace*{-0.6 in } \frac{1}{2 } \sum_{n=1}^n\mathbb{e}\{2z_n(t)(1-\delta_n(t))\alpha_n(t ) - \nonumber\\ & & \hspace*{-0.6 in } ( z_n(t ) + \alpha_n(t))p_n(t)|z_n(t)\}\nonumber\\ & \hspace*{-1.0in}\leq & \hspace*{-0.6 in } b+\sum_{n=1}^n\mathbb{e}\{z_n(t)(1-\delta_n)\alpha_n(t)|z_n(t)\ } + \nonumber\\ & & \hspace*{-0.6 in } \sum_{k=1}^k\mathbb{e}\{x_k(t)(r_k(t ) - d_k(t))|x_k(t)\ } - \nonumber \\ & & \hspace*{-0.6 in } \sum_{n=1}^n\mathbb{e}\{(z_n(t ) + \alpha_n(t))p_n(t)|z_n(t)\}. \nonumber \ ] ] where @xmath72 is a constant . in part 1 ) of lemma [ lm : lm1 ] , if @xmath82 , we have @xmath83 according to ( [ eq : sellconst ] ) . the the objective function of problem ( [ eq : objdrift ] ) becomes @xmath217 we first prove lemma [ lm : lm1]-[item : item1a ] ) . if @xmath84 , we assume @xmath218 . then we have @xmath87 according to ( [ eq : batredecontr ] ) . accordingly , the object function ( [ eq : lmqt ] ) is transformed to @xmath219 @xmath220 c(t)+\nonumber\\ & & \sum_{i \neq k}{x_i(t)(r_i(t ) - d_i(t ) ) } - \sum_{n=1}^n{(z_n(t ) + \alpha_n(t))p_n(t)}. \nonumber\end{aligned}\ ] ] the above inequality is due to @xmath84 and @xmath221 . the last expression shows , given the assumption @xmath218 , we may find another feasible electricity allocation scheme @xmath222 , which can achieve a smaller objective value by choosing @xmath85 and @xmath87 . this contradicts with the assumption @xmath218 . thus , we prove that @xmath85 when @xmath84 , under the situation @xmath223 . we then prove the second part of lemma [ lm : lm1]-[item : item1a ] ) . it follows ( [ eq : batredecontr ] ) that @xmath85 if @xmath224 . then ( [ eq : lmqt ] ) becomes @xmath225 c(t)+\nonumber\\ & & \hspace{-0.2 in } \sum_{i \neq k}{x_i(t)(r_i(t ) - d_i(t ) ) } - \sum_{n=1}^n{(z_n(t ) + \alpha_n(t))p_n(t)}.\nonumber\end{aligned}\ ] ] the above inequality is due to @xmath226 and @xmath227 . the last expression shows , given the assumption @xmath224 , we may find another electricity allocation scheme with @xmath228 , which can achieve a smaller objective value by choosing @xmath85 and @xmath87 . this contradicts with the assumption @xmath229 . we thus prove that @xmath87 when @xmath86 , under the situation @xmath223 , which completes the proof of lemma [ lm : lm1]-[item : item1a ] ) . we next prove lemma [ lm : lm1]-[item : item1b ] ) . for the first part , if @xmath88 , we assume @xmath230 . following ( [ eq : objdriftfull ] ) and @xmath83 , we have @xmath231 @xmath232 - \alpha_n(t)p_n(t ) \nonumber\ ] ] @xmath233 @xmath234 - \alpha_n(t)p_n(t ) \nonumber\ ] ] @xmath235c(t ) + \sum_{k=1}^kx_k(t)(r_k(t ) - d_k(t ) ) + \nonumber\\ & & \hspace{-0.15 in } \sum_{j\neq n}(z_j(t)(1-\delta_j)\alpha_j(t ) - ( z_j(t ) + \alpha_j(t))p_j(t ) ) + \nonumber\\ & & \hspace{-0.15 in } z_n(t)(1-\delta_n)\alpha_n(t ) - ( z_n(t ) + \alpha_n(t))(1-\delta_n)\alpha_n(t).\nonumber\end{aligned}\ ] ] the above inequality is due to @xmath88 and the assumption @xmath236 . the last equality shows , given the assumption @xmath236 , we may find another electricity allocation scheme with @xmath237 and @xmath238 , which can achieve a smaller objective value . this contradicts with the previous assumption . thus , we have @xmath89 . for the second part of lemma [ lm : lm1]-[item : item1b ] ) , assume @xmath239 for @xmath240.it follows ( [ eq : sellconst ] ) that @xmath83 . the objective function ( [ eq : objdriftfull ] ) can be written as @xmath241 @xmath242 @xmath243c(t ) + \sum_{k=1}^kx_k(t)(r_k(t ) - d_k(t ) ) + \nonumber\\ & & \sum_{j\neq n}(z_j(t)(1-\delta_j)\alpha_j(t ) ) - \sum_{j\neq n}((z_j(t ) + \alpha_j(t))p_j(t ) ) . \nonumber\ ] ] the first inequality is due to @xmath240 and the assumption @xmath239 . the second inequality is due to the non - negativity of @xmath50 and @xmath23 . the last equation shows , given the assumption @xmath239 , we may find another electricity allocation scheme with @xmath91 and @xmath244 , which can achieve a smaller objective value . this contradicts with the previous assumption . thus , we have @xmath245 , which completes the proof of lemma [ lm : lm1]-[item : item1b ] ) . in part [ enu : enu2 ] ) of lemma [ lm : lm1 ] , if @xmath93 , we have @xmath92 according to ( [ eq : sellconst ] ) . the objective function ( [ eq : objdrift ] ) becomes @xmath246 we can prove part [ enu : enu2 ] ) with a similar approach as in the case of part [ enu : enu1 ] . the detailed proof is omitted for brevity . since @xmath247 and @xmath248 , we have @xmath85 when @xmath99 , and @xmath87 when @xmath249 according to lemma [ lm : lm1]-[enu : enu1 ] ) . similarly , since @xmath250 and @xmath248 , we obtain @xmath85 when @xmath251 , and @xmath87 when@xmath98 according to lemma [ lm : lm1]-[enu : enu2 ] )

microgrid ( mg ) is a promising component for future smart grid ( sg ) deployment . the balance of supply and demand of electric energy is one of the most important requirements of mg management . in this paper , we present a novel framework for smart energy management based on the concept of quality - of - service in electricity ( qose ) . specifically , the resident electricity demand is classified into _ basic usage _ and _ quality usage_. the basic usage is always guaranteed by the mg , while the quality usage is controlled based on the mg state . the microgrid control center ( mgcc ) aims to minimize the mg operation cost and maintain the outage probability of quality usage , i.e. , qose , below a target value , by scheduling electricity among renewable energy resources , energy storage systems , and macrogrid . the problem is formulated as a constrained stochastic programming problem . the lyapunov optimization technique is then applied to derive an adaptive electricity scheduling algorithm by introducing the qose virtual queues and energy storage virtual queues . the proposed algorithm is an online algorithm since it does not require any statistics and future knowledge of the electricity supply , demand and price processes . we derive several `` hard '' performance bounds for the proposed algorithm , and evaluate its performance with trace - driven simulations . the simulation results demonstrate the efficacy of the proposed electricity scheduling algorithm . smart grid , microgrids , distributed renewable energy resource , lyapunov optimization , stability .

Myanmar prisoners walk out of Insein Prison in Yangon, Myanmar Wednesday, Oct. 12, 2011. Myanmar has begun releasing more then 6,300 prisoners but has held back on freeing some prominent political prisoners.... (Associated Press) Myanmar freed comedian and government critic Zarganar as it began releasing 6,300 convicts in a liberalizing move Wednesday, but kept several key political detainees behind bars, dampening hopes for a broader amnesty. Relatives of convicts gathered expectantly at prisons around the country and held emotional reunions with those released, a day after the country's new civilian president issued an amnesty for inmates _ many of them ordinary criminals _ but without disclosing any names. It was not clear how many of the country's estimated 2,000 political detainees were included in the amnesty. Relatives of some of them confirmed their release, while others said they were told by prison officials that their loved ones were not among those to be freed. "The freedom of each individual is invaluable, but I wish that all political prisoners would be released," said Myanmar's most prominent pro-democracy campaigner and Nobel peace laureate Aung San Suu Kyi. Suu Kyi's National League for Democracy confirmed the release of 155 political detainees, including members of the party, spokesman Nyan Win said. But others may have not yet contacted anyone. A major release of political detainees has been eagerly awaited by Myanmar's opposition, as well as foreign governments and the U.N., as a gesture toward liberalization by the elected government after decades of harsh military rule. A failure to release a significant number could hamper the country's efforts to burnish its human rights record and win a lifting of Western economic and political sanctions. President Thein Sein, a retired senior army officer who took office at the head of an elected government in March, has launched a series of economic reforms and eased limits on freedom of speech by relaxing censorship and unblocking banned websites. He also has started a dialogue with Suu Kyi, made calls for peace with ethnic minority rebel groups and suspending a controversial China-backed hydropower dam project after a public outcry. One of the most prominent figures to be freed was comedian and activist Zarganar, who was serving a 35-year sentence in Myitkyina prison in northernmost Kachin State. Zarganar was detained in 2008 after giving interviews to foreign media criticizing the former military rulers for being slow to respond to Cyclone Nargis, which left nearly 140,000 people dead or missing. He was convicted of causing public alarm and illegally giving information to the press. "I am not happy at all, as none of my 14 so-called political prisoner friends from Myitkyina prison are among those freed today," he told The Associated Press by phone as he waited to board a plane to Yangon. "I will be happy and I will thank the government only when all of my friends are freed," he said. Relatives said several top members of some of the country's ethnic minority political parties were also among those freed. However, the sister of famous former student leader Min Ko Naing said she was told he was not on the list of those to be freed. "We are used to these ups and downs," Kyi Kyi Nyunt said. Min Ko Naing has been serving a 65-year sentence at a prison in Shan State in northeastern Myanmar since 2008 for staging a street protest against a massive fuel price hike. He was arrested in August 2007 along with other well-known former students who were previously jailed after being at the forefront of a failed pro-democracy uprising in 1988. At least one of his "'88 Generation" comrades, Ko Htay Kywe, also was not being released, according to his brother-in-law, Phyo Min Thein. The United States, which has been seeking ways to re-engage with Myanmar, has said it wants all political detainees released. State Department spokeswoman Victoria Nuland said Tuesday that the U.S. would be keeping a close eye on who is released under the amnesty. Washington has long isolated Myanmar with political and economic sanctions because of the former junta's failure to hand power to a democratically elected government and its poor human rights record. ___ Associated Press writer Matthew Pennington in Washington contributed to this report. ||||| The release of roughly 2,000 political detainees including pro-democracy campaigners, journalists, monks and lawyers, has long been a key demand of Western powers that have imposed sanctions on the country also known as Burma . The Thailand-based Assistance Association for Political Prisoners said at least 70 political detainees were being freed. "I think we will see some more," said spokesman Aung Khaing Min. The prominent satirist and vocal government critic Zarganar, who goes by one name, was among those released as part of a pardon of more than 6,300 prisoners by the new nominally civilian leadership, his sister-in-law said. The dissident was arrested in 2008 after organising deliveries of aid to victims of Cyclone Nargis – which left 138,000 people dead or missing – and sentenced to 59 years' imprisonment, later reduced to 35 years. Several hundred prisoners were being released from Rangoon's notorious Insein Prison, including student activist Aung Kyaw Soe, who was arrested in 1990 and sentenced to death, later reduced to life in prison. "I was released after serving 21 years and two days. I am glad that I was freed but I am also sorry for the people who are still inside the prison," he said outside the jail gates. Many of Burma's political prisoners were sentenced to decades in jail and have endured "torture and other forms of cruel, inhuman or degrading treatment", according to rights group Amnesty International. A mass pardon of dissidents would be arguably the clearest sign yet of change under a new government that has reached out to critics including pro-democracy leader Aung San Suu Kyi, who was freed in November. State television announced on Tuesday that more than 6,300 elderly, sick, disabled or well-behaved prisoners would be granted an amnesty from Wednesday "on humanitarian grounds". It said freeing detainees would allow them to "help to build a new nation". President Thein Sein, a former general and senior junta figure, has surprised critics by signalling a series of political reforms since taking power following a controversial election last November. He has been applauded by international observers for holding direct talks with Suu Kyi, who spent most of the past two decades locked up by the junta. In a rare concession to public opinion in the authoritarian nation, the government last month suspended construction of a controversial mega-dam, risking the anger of traditional ally China, which is backing the project. A top US official, Kurt Campbell, on Monday hailed "dramatic developments" in Burma including what he described as "very consequential dialogue" between the Nobel Peace Prize winner and the leadership. He hinted that concrete moves towards democracy by Burma could lead to an easing of sanctions. "We will match their steps with comparable steps," he said. The new regime, which came to power after elections held a few days before Suu Kyi's release, appears keen to improve its image and in August held the first talks between her and Thein Sein. Ms Suu Kyi, whose party won 1990 elections but was never allowed to take power, has said she believes Thein Sein genuinely wants to carry out reforms, but cautioned it was too soon to say whether he would succeed.

– Burma today began releasing the 6,300 prisoners who will be granted amnesty, but so far the number of political detainees released does not come close to the estimated 2,000 who are in jail. The Telegraph puts the number of political prisoners released at 120, while the AP reports 155, including members of Aung San Suu Kyi's National League for Democracy. Other inmates released were ordinary criminals, many of them elderly, ill, disabled, or well-behaved. One of the most high-profile prisoners released today is activist Zarganar, who was sentenced to 35 years in 2008 after criticizing the government’s slow response to Cyclone Nargis and organizing aid deliveries to victims. Others released included top members of ethnic minority political parties as well as student activist Aung Kyaw Soe, who had served 21 years. It's the clearest move yet from the country's new government toward liberalization, but the AP notes that Burma likely must release a significant number of political prisoners if it wants economic and political sanctions from the West lifted.

SECTION 1. SHORT TITLE. This Act may be cited as the ``Hudson-Fulton-Champlain 400th Commemoration Commission Act of 2002''. SEC. 2. FINDINGS AND PURPOSE. (a) Findings.--The Congress finds the following: (1) The first European exploration of the Hudson River and Lake Champlain and the introduction of steam navigation to maritime commerce were events of major historical importance, both in the United States and internationally. (2) In 1609, Englishman Henry Hudson, acting in service of the Dutch East India Company, was the first European to sail up the river later named for him in the vessel HALF MOON, and French explorer Samuel de Champlain was the first European to see the lake later named for him. (3) These voyages were 2 of the most significant passages in the European exploration and discovery of America, and began 2 of the earliest contacts in the New World between Native Americans and Europeans. (4) These explorations led to the establishment of Fort Orange, Dutch and later English settlement of what is now the capital city of the State of New York, and settlement of French Quebec settlements as far south as Lake George. From these early settlements came an influence on our history, culture, law, commerce, and traditions of liberty which extends to the present day, and which is constantly reflected in the position of the United States as the leader of the nations of the free world. (5) In 1807, Robert Fulton navigated the Hudson River from the city of New York to Albany in the steamboat CLERMONT, successfully inaugurating steam navigation on a commercial basis. This event is one of the most important events in the history of navigation. It revolutionized waterborne commerce on the great rivers of the United States, transformed naval warfare, and fostered international relations through transoceanic travel and trade. (6) The National Park Service owns and operates significant resources in New York related to the early history of the nation and the Hudson River Valley. (7) In 2002 the State of New York enacted legislation establishing a State Hudson-Fulton-Champlain Commission. (b) Purpose.--The purpose of this Act is to establish the Hudson- Fulton-Champlain 400th Commemoration Commission to-- (1) ensure a suitable national observance of the Henry Hudson, Robert Fulton, and Samuel de Champlain 2009 anniversaries through cooperation with and assistance to the programs and activities of New York, New Jersey, and Vermont; (2) assist in ensuring that Hudson-Fulton-Champlain 2009 observances provide an excellent visitor experience and beneficial interaction between visitors and the natural and cultural resources of the New York, New Jersey, and Vermont sites; (3) assist in ensuring that Hudson-Fulton-Champlain 2009 observances are inclusive and appropriately recognize the diverse Hudson River and Lake Champlain communities that developed over 4 centuries; (4) facilitate international involvement in the Hudson- Fulton-Champlain 2009 observances; (5) support and facilitate marketing efforts for a commemorative coin, a commemorative stamp, and related activities for the Hudson-Fulton-Champlain 2009 observances; and (6) assist in the appropriate development of heritage tourism and economic benefits to the United States. SEC. 3. DEFINITIONS. In this Act: (1) Commemoration.--The term ``commemoration'' means the commemoration of-- (A) the 200th anniversary of Robert Fulton's voyage in the CLERMONT; (B) the 400th anniversary of Henry Hudson's voyage in the HALF MOON; and (C) the 400th anniversary of Samuel de Champlain's voyage. (2) Commission.--The term ``Commission'' means the Hudson- Fulton-Champlain 400th Commemoration Commission established by section 4(a). (3) Governors.--The term ``Governors'' means the Governors of the States of New York, New Jersey, and Vermont. (4) Secretary.--The term ``Secretary'' means the Secretary of the Interior. (5) States.--The term ``States''-- (A) means the States of New York, New Jersey, and Vermont; and (B) includes agencies and entities of each such State. SEC. 4. HUDSON-FULTON-CHAMPLAIN 400TH COMMEMORATION COMMISSION. (a) In General.--There is established a commission to be known as the ``Hudson-Fulton-Champlain 400th Commemoration Commission''. (b) Membership.-- (1) In general.--The Commission shall be composed of 31 members, of whom-- (A) 3 members shall be appointed by the Secretary, after consideration of the recommendations of the Governors; (B) 14 members shall be appointed by the Secretary, after consideration of the recommendations from the Members of the House of Representatives whose districts encompass the Hudson River Valley and Champlain Valley; (C) 6 members shall be appointed by the Secretary, after consideration of the recommendations from the Members of the Senate from New York, New Jersey, and Vermont; (D) 2 members shall be employees of the National Park Service, of whom-- (i) one shall be the Director of the National Park Service (or a designee); and (ii) one shall be an employee of the National Park Service having experience relevant to the commemoration, who shall be appointed by the Secretary; (E) one member shall be appointed by the Secretary, and shall be an individual knowledgeable of the Hudson River Valley National Heritage Area; and (F) 5 members shall be appointed by the Secretary, and shall be individuals that have an interest in, support for, and expertise appropriate to, the commemoration. (2) Term; vacancies.-- (A) Term.--Each member of the Commission shall be appointed for the life of the Commission. (B) Vacancies.-- (i) In general.--A vacancy on the Commission shall be filled in the same manner in which the original appointment was made. (ii) Partial term.--A member appointed to fill a vacancy on the Commission shall serve for the remainder of the term for which the predecessor of the member was appointed. (3) Meetings.-- (A) In general.--The Commission shall meet-- (i) at least twice each year; or (ii) at the call of the Chairperson or the majority of the members of the Commission. (B) Initial meeting.--Not later than 30 days after the date on which all members of the Commission have been appointed, the Commission shall hold the initial meeting of the Commission. (4) Voting.-- (A) In general.--The Commission shall act only on an affirmative vote of a majority of the members of the Commission. (B) Quorum.--A majority of the Commission shall constitute a quorum. (5) Chairperson and vice chairperson.--(A) The Commission shall elect the chairperson and the vice chairperson of the Commission on an annual basis. (B) The vice chairperson shall serve as the chairperson in the absence of the chairperson. (c) Duties.-- (1) In general.--The Commission shall-- (A) plan, develop, and execute programs and activities appropriate to commemorate the 400th anniversary of the voyage of Henry Hudson, the first European to sail up the Hudson River, the 200th anniversary of the voyage of Robert Fulton, the first person to use steam navigation on a commercial basis, the 400th anniversary of the voyage of Samuel de Champlain, the first European to discover and explore Lake Champlain; (B) facilitate Hudson-Fulton-Champlain-related activities throughout the United States; (C) coordinate its activities with State commemoration commissions and appropriate Federal Government agencies, including the Departments of Agriculture, Defense, State, and Transportation, the National Park Service with respect to the Hudson River Valley National Heritage Area, and the American Heritage Rivers Initiative Interagency Committee established by Executive Order 13061, dated September 11, 1997; (D) encourage civic, patriotic, historical, educational, religious, economic, and other organizations throughout the United States to organize and participate in anniversary activities to expand the understanding and appreciation of the significance of the voyages of Henry Hudson, Robert Fulton, and Samuel de Champlain; (E) provide technical assistance to States, localities, and nonprofit organizations to further the commemoration; (F) coordinate and facilitate for the public scholarly research on, publication about, and interpretation of, the voyages of Henry Hudson, Robert Fulton, and Samuel de Champlain; and (G) ensure that the Hudson-Fulton-Champlain 2009 anniversaries provide a lasting legacy and long-term public benefit by assisting in the development of appropriate programs and facilities. (2) Plans; reports.-- (A) Strategic plan; annual performance plans.--The Commission shall prepare a strategic plan in accordance with section 306 of title 5, United States Code, and annual performance plans in accordance with section 1115 of title 31, United States Code, for the activities of the Commission carried out under this Act. (B) Final report.--Not later than September 30, 2010, the Commission shall submit to the Secretary a final report that contains-- (i) a summary of the activities of the Commission; (ii) a final accounting of funds received and expended by the Commission; and (iii) the findings and recommendations of the Commission. (d) Powers of the Commission.--The Commission may-- (1) disperse funds, and accept donations of personal services and real and personal property related to Hudson- Fulton-Champlain 2009 and of the significance of Hudson, Fulton, and Champlain in the history of the United States; (2) appoint such advisory committees as the Commission determines to be necessary to carry out this Act; (3) authorize any member or employee of the Commission to take any action that the Commission is authorized to take by this Act; (4) procure supplies, services, and property, and make or enter into contracts, leases, or other legal agreements, to carry out this Act (except that any contracts, leases, or other legal agreements made or entered into by the Commission shall not extend beyond the date of termination of the Commission); (5) use the United States mails in the same manner and under the same conditions as other Federal agencies; (6) subject to approval by the Commission, make grants in amounts not to exceed $20,000 to communities and nonprofit organizations to develop programs to assist in the commemoration; and (7) make grants to research and scholarly organizations to research, publish, or distribute information relating to the early history of the voyages of Hudson, Fulton, and Champlain. (e) Commission Personnel Matters.-- (1) Compensation of members of the commission.-- (A) In general.--Except as provided in subparagraph (B), a member of the Commission shall serve without compensation. (B) Federal employees.--A member of the Commission who is an officer or employee of the Federal Government shall serve without compensation in addition to the compensation received for the services of the member as an officer or employee of the Federal Government. (C) Travel expenses.--A member of the Commission shall be allowed travel expenses, including per diem in lieu of subsistence, at rates authorized for an employee of an agency under subchapter I of chapter 57 of title 5, United States Code, while away from the home or regular place of business of the member in the performance of the duties of the Commission. (2) Staff.-- (A) In general.--The Chairperson of the Commission may, without regard to the civil service laws (including regulations), appoint and terminate an executive director and such other additional personnel as are necessary to enable the Commission to perform the duties of the Commission. (B) Confirmation of executive director.--The employment of an executive director shall be subject to confirmation by the Commission. (3) Compensation.-- (A) In general.--Except as provided in subparagraph (B), the Chairperson of the Commission may fix the compensation of the executive director and other personnel without regard to the provisions of chapter 51 and subchapter III of chapter 53 of title 5, United States Code, relating to classification of positions and General Schedule pay rates. (B) Maximum rate of pay.--The rate of pay for the executive director and other personnel shall not exceed the rate payable for level V of the Executive Schedule under section 5316 of title 5, United States Code. (4) Detail of government employees.-- (A) Federal employees.-- (i) In general.--At the request of the Commission, the head of any Federal agency may detail, on a reimbursable or nonreimbursable basis, any of the personnel of the agency to the Commission to assist the Commission in carrying out the duties of the Commission under this Act. (ii) Civil service status.--The detail of an employee under clause (i) shall be without interruption or loss of civil service status or privilege. (B) State employees.--The Commission may-- (i) accept the services of personnel detailed from States (including subdivisions of States); and (ii) reimburse States for services of detailed personnel. (5) Volunteer and uncompensated services.--Notwithstanding section 1342 of title 31, United States Code, the Commission may accept and use voluntary and uncompensated services as the Commission determines necessary. (6) Support services.--The Director of the National Park Service shall provide to the Commission, on a reimbursable basis, such administrative support services as the Commission may request. (f) Procurement of Temporary and Intermittent Services.--The Chairperson of the Commission may procure temporary and intermittent services in accordance with section 3109(b) of title 5, United States Code, at rates for individuals that do not exceed the daily equivalent of the annual rate of basic pay prescribed for level V of the Executive Schedule under section 5316 of that title. (g) FACA Nonapplicability.--Section 14(b) of the Federal Advisory Committee Act (5 U.S.C. App.) shall not apply to the Commission. (h) No Effect on Authority.--Nothing in this section supersedes the authority of the States or the National Park Service concerning the commemoration. (i) Termination.--The Commission shall terminate on December 31, 2010.

Hudson-Fulton-Champlain 400th Commemoration Commission Act of 2002 - Establishes the Hudson-Fulton-Champlain 400th Commemoration Commission to plan, develop, and execute programs and activities appropriate to commemorate the 400th anniversary of the voyage of Henry Hudson (the first European to sail up the Hudson River in the vessel Half Moon), the 200th anniversary of the voyage of Robert Fulton (navigated the Hudson River in the steamboat Clermont, becoming the first person to use steam navigation on a commercial basis), and the 400th anniversary of the voyage of Samuel de Champlain (the first European to discover and explore Lake Champlain).

the x - ray source cygnus x-1 was discovered by bowyer et al ( 1965 ) , and its optical counterpart , a spectroscopic binary at a distance of @xmath3 2 kpc with a 5.6 day period ( hde226868 ) , was identified by webster and murdin ( 1972 ) and bolton ( 1972 ) . the primary is a supergiant , and the mass of the secondary is at least @xmath4 ( gies & bolton 1986 ) , making it a black hole candidate and a high mass x - ray binary . the x - ray source , which has been observed from kev to mev energies , is thought to be powered by accretion ( e.g. petterson 1978 ) . soft x - radiation may be produced in an accretion disk close to the black hole , and hard x - rays by inverse compton scattering in a separate hot plasma ; see liang and nolan ( 1984 ) for a review . recently , a relativistic jet has been detected in the radio ( stirling et al . 2001 ) , and romero et al . ( 2002 ) have suggested that cygnus x-1 is a microblazar , that is , that we are observing it close to the axis of the jet . cygnus x-1 is known to exhibit two states of x - ray emission , which are thought to depend on the accretion rate ( esin et al . the first , more common one , is the hard state , in which the 20 - 200 kev flux is roughly one crab , and the @xmath510 kev emission is about 0.5 crab . the second is the soft state , in which the low energy x - ray flux increases by a factor of 2 - 4 , while the high energy flux decreases by a factor of about 2 . transitions between the two states and flaring have been documented extensively ( ling et al . 1997 ; zhang et al . 1997 ; cui et al . 2002 ; mcconnell et al . 2002 ) , and both states exhibit variability of a factor of two or so on all timescales . in this paper we report on seven episodes of long , intense gamma - ray emission from this source ; we refer to them as _ outbursts ( and identify them by their dates ) , to distinguish them from the shorter , less intense flaring which has been documented previously . one of these outbursts , 950325 , was found by mazets et al . ( 1995 ) and initially thought to be a gamma - ray burst ; subsequently , however , its source was found to be cygnus x-1 by m. briggs ( private communication , 1995 ) . later , stern et al . ( 2001 ) called attention to five outbursts on 1999 april 19 - 21 . during the two brightest events , the hard x - ray flux increased by over an order of magnitude for @xmath3 1000 s. observations by _ ulysses and konus - _ wind of still three more outbursts in 2002 - 2003 have prompted us to reanalyze all the available data in order to obtain better energy spectra and a more precise source location as well . the outbursts reported here were discovered in the time history data of the gamma - ray burst ( grb ) detectors aboard the _ wind , ulysses , and _ compton gamma - ray observatory ( cgro ) spacecraft ( konus , grb , and the burst and transient source experiment , or batse , experiments respectively ) . in general , the data used were for the non - triggered modes , with low temporal and spectral resolution ( 0.25 - 2.9 s and 3 channels , respectively ) . although in some cases , the emission was intense enough to trigger batse , the data obtained in the triggered modes had too small a duration to cover the entire outburst , and the lower time resolution continuous data have been used for most of our analysis . table 1 gives the dates , times , and durations of the seven events , as well as the spacecraft which observed them , and the spectral state and orbital phase of cyg x-1 . to determine the source of the outbursts , we have employed the usual method of interplanetary network ( ipn ) triangulation for a repeating source ( e.g. hurley et al . 1999 ) . in all cases , the ipn consisted of only two widely separated spacecraft ( _ ulysses and either cgro or _ wind ) , so a single annulus of location was obtained for each flare . the seven annuli were combined statistically to produce the 1 , 2 , and 3 @xmath2 error ellipses shown in figure 1 . the only known hard x - ray source in this region is cyg x-1 , which lies at the @xmath3 95 % confidence level . _ _ _ _ although _ ulysses observed all seven of the outbursts in table 1 , it was in a mode in which no energy spectra were accumulated . wind observed 6 of the 7 outbursts ( one outburst , 990421b , occurred during a period when the data were contaminated by solar particles ) , and we have used the data from it exclusively for time - resolved spectral analysis . the time and energy resolutions vary depending on the mode of operation . for five outbursts we have data in three energy channels ( nominally 10 - 50 , 50 - 200 , and 200 - 750 kev , or g1 , g2 , and g3 , respectively ) which span the entire event . in the sixth case ( 950325 ) a cosmic gamma - ray burst fortuitously triggered konus during the outburst , allowing it to record multi - channel energy spectra for a total of 360 s , starting 120 s after the grb trigger , when the 15 s long grb had ceased emitting . in addition , for this event , there are also 3 channel data . because the most detailed data are available for it , we discuss this outburst first . _ the 950325 outburst is presented in detail in figure 2 . in the top three panels , the time histories in the g1 , g2 , and g3 windows are shown , and in the bottom panels , the hardness ratios g2/g1 and g3/g2 . the letters a - d indicate the intervals where energy spectra have been analyzed . ( the results of this and other analyses are summarized in table 2 . ) in particular , b marks the 360 s interval where multi - channel spectra were accumulated . the gap following b is the interval where the data were transferred to the onboard tape recorder . the hardness ratios display a weak but obvious spectral variability . from them , it is reasonable to assume that the multi - channel energy spectra measured in interval b , during the fading stage of the flare , also characterize the spectrum of the preceding , intense phase . the multi - channel spectrum is presented in figure 3 in @xmath6 units . ( the spectral deconvolution procedure has been described by terekhov et al . the solid line gives the best fit spectrum , @xmath7 , with @xmath8 for 18 degrees of freedom . this spectral shape is consistent with that of the cyg x-1 hard state . the 15 - 300 kev time histories of the other outbursts are presented in figures 4 - 9 . the vertical dotted lines and letters at the top of the konus plots indicate the intervals over which 3 channel energy spectra were accumulated to improve statistics . fits were done with the function @xmath9 , and the fitting parameters are given in table 2 . e@xmath10 , the peak energy , was obtained from the spectrum expressed in @xmath6 units . the fluences and peak fluxes , given in table 3 , were calculated assuming no spectral evolution over the intervals considered . it should be noted that an omnidirectional sensor detects an outburst from a source as a temporary increase in the count rate over an average background level . clearly in this case that level includes any persistent flux from cyg x-1 . thus the total flux during an outburst will be the sum of the persistent and flaring fluxes detected by konus . however , the value of the persistent flux from cyg x-1 at time intervals adjacent to the outburst is poorly known . accordingly the fluences and peak fluxes in table 3 are only to be considered estimates of the outburst component . long - term observations of cyg x-1 in x - rays and soft gamma - rays from heao 3 ( ling et al . 1987 ) , batse ( ling et al . 1997 ) , mir - kvant ( borkus et al . 1995 ) , and bepposax ( frontera et al . 2001 ) have shown that the source spends most of the time in the hard state . according to batse data for 1991 - 1999 ( mcconnell et al . 2002 ) , the hard flux in the 20 - 100 kev energy range varied between 0.2 and 0.36 photons @xmath11 s@xmath12 , roughly the average value corresponding to the @xmath13 level in the 45 - 140 kev band identified by ling et al . ( 1987 ) . in 1999 april , several outbursts lasting up to 1000 s were found in the batse data ( stern et al . 2001 ) . the peak fluxes in the 50 - 300 kev range , 0.3 - 1.1 photons @xmath11 s@xmath12 , were significantly higher than the average value of @xmath14 . transitions to the soft state lasting for several months were observed only a few times . according to the data of the all sky monitor aboard the _ rossi x - ray timing explorer ( rxte / asm , mcconnell et al . 2002 ) , the soft x - ray ( 2 - 10 kev ) count rates increase from @xmath15 after transitions to the soft state . from the batse and rxte light curves we have ascertained that outbursts 950110 , 950325 , 990421a and b , and 030212 occured while cyg x-1 was in the hard state whereas outbursts 020224 and 020331 arose from the soft state . _ broadband spectral observations of cyg x-1 from numerous spacecraft and combinations of spacecraft have been used to study comprehensively the spectral shapes at various times in order to deduce the emission mechanism and the geometry of the regions emitting and reprocessing radiation ( mir - kvant : borkus et al . 1995 ; cgro : ling et al . 1997 ; ginga and cgro : gierlinski et al . 1997 ; rxte : dove et al . 1998 ; asca , rxte , and cgro : gierlinski et al . 1999 ; bepposax : frontera et al . 2001 ; and cgro and bepposax : mcconnell et al . the accuracy of our data is insufficient for such a thorough analysis of source models . rather , we have focused on obtaining the essential information on a new feature of cyg x-1 activity from limited observational data using the simplest model spectra , namely a power law , @xmath16 , or a power law with an exponential cutoff , @xmath17 . apart from the lack of high resolution spectral data , the most serious difficulties in our data processing are connected with slow changes in the background level , especially in the low energy ranges . background count rates in the g1 window and , to a lesser extent , in g2 , are strongly affected by the activity of cosmic x - ray sources and vary , even when the sun is quiet , by @xmath18 , averaged over hours and days . for this reason , for example , we do not attempt spectral fits for the long , weak onsets of outbursts 950110 and 950325 . the intense stage of each outburst was subdivided into several time intervals in some concordance with the temporal behaviour of the hardness ratio , as shown in figures 2 and 4 - 9 . spectral parameters for all of these intervals were determined using the following procedure . the counts accumulated in energy band g@xmath19 ( i=1 , 2 , 3 ) can be represented as an integral over an energy loss spectrum @xmath20 ( e ) \mathrm{d } e\ ] ] using a model photon spectral function @xmath21 and the detector response matrix @xmath22 . the resulting system of three equations with unknowns a , @xmath23 , and e@xmath24 was solved by the marquardt - levenberg method and the uncertainties in the parameters were calculated from the covariance matrix . in the case of the exponentially attenuated power law , parameters @xmath23 and e@xmath24 are strongly correlated . the peak energy e@xmath10 for a @xmath25 spectrum is a more robust characteristic . estimates of the errors in the spectral parameters were checked by numerical simulations , i.e. by introducing poisonnian - distributed deviations to the count rates g1 , g2 , and g3 , applying the procedure described above , and analyzing the distributions of the spectral parameters . the results of the simulations are in very good agreement with estimates from the covariance matrix . all of these data are collected in table 2 , which includes an additional interval b * for 950325 . this interval , where g1 , g2 , and g3 data were available , partially overlaps interval b. from this it is evident that the parameters obtained by both methods agree well to within their uncertainties . the 15 - 300 kev fluences and peak fluxes for all the outbursts are presented in table 3 . the main conclusions which can be drawn from these data are the following . * an exponential cutoff is essential when fitting outbursts arising from the hard state . the parameters @xmath23 and e@xmath24 for these outbursts are consistent with the values for the hard state of cyg x-1 reported in literature . * the spectra of the 2002 soft state outbursts are softer in our energy range . the photon spectra of 020331 are well fit by a single slope power law with @xmath26 , which is certainly softer than any spectrum observed in the hard state . the spectra of 020224 have an intermediate shape and display a low e@xmath24 with large uncertainties in @xmath23 . * the hardness ratio g2/g1 varies slightly during outbursts , but it does not display any clear correlation with the luminosity . the only exception is observed in the outburst of 990421b , where the hardness decreases substantially at the peak ( see stern , beloborodov , & poutanen 2001 ) * in general , it seems that giant outbursts maintain the spectral parameters , and hence emission mechanism , of the current underlying spectral state of cyg x-1 , even though the 15 - 300 kev peak fluxes are up to ten times higher than the persistent emission fluxes . the corresponding fraction of the peak luminosity in these outbursts approaches one tenth of the eddington luminosity for an object with @xmath27 . the soft and hard states of cygnus x-1 and other galactic black hole candidates have comparable bolometric luminosities , but different energy spectra ( e.g. ling et al . 1997 ; zdziarski et al . 2002 ) . the hard x - ray spectra of these sources are typically characterized by power law with exponential cutoff with photon index @xmath28 and cutoff energy @xmath29 kev ( phlips et al . 1996 , gierlinski et al . 1997 , dove et al . 1998 ) , which are consistent with those in table 2 for the first four outbursts and the seventh one . many authors have interpreted them as thermal comptonization with optical depth @xmath30 and electron temperature @xmath31 kev ( for recent studies see maccarone & coppi , 2002 ) . the model for transitions between the soft and hard states discussed in a number of recent works is based on the idea of accretion disk transformations . in the soft state the accretion proceeds via a standard optically thick accretion disk ( shakura & sunyaev , 1973 ) emitting a blackbody soft x - ray peak and a nonthermal tail resulting from coronal activity in the disk . in the hard state the inner part of the disk is thought to form a hot geometrically thick corona ( see e.g. barrio , done & nayakshin , 2002 , poutanen , krolik & ryde , 1997 , and references therein ) with a moderate ( @xmath30 ) optical depth . the outer region of the disk , beyond a few tens to one hundred gravitational radii , still remains optically thick , emitting a cooler ( 0.1 - 0.2 kev ) and weaker blackbody component . the physical grounds for such a transformation could be a transition of the inner part of the disk into a regime balancing between adaf and standard disk modes ( esin et al . however such a regime requires a fine tuning which would clearly be violated during giant outbursts ( stern , beloborodov & poutanen , 2001 ) . an alternative to disk accretion for the case of the hard state could be accretion of the companion wind with a near - critical angular momentum ( illarionov & sunyaev , 1975 ) . then , instead of a standard optically thick disk , a small - scale disk with @xmath30 can appear . this scenario can naturally describe the hard state spectrum ( beloborodov & illarionov , 2001 ) in terms of thermal comptonization in the small disk within a few gravitational radii . no difficulties with the large observed variabilities arise in this model . the absence of a clear correlation between luminosity and hardness is noteworthy . actually , the presence of a luminosity - hardness correlation or anti - correlation depends on many details , including the geometry of the emission region , the soft radiation , and pair production . if the comptonizing plasma is pair - dominated , then the temperature is a weak function of the luminosity : pair production provides a thermostatic effect ( see , e.g. malzac , beloborodov , & poutanen , 2001 ) . the spectrum in this case is softer at higher luminosities ( if the geometry is fixed ) , but the dependence is weak ( stern et al . a luminosity - hardness anti - correlation is expected , but we do not observe it because of statistics . what triggers the giant outbursts ? the normal time variability of cygnus x-1 has a broad power density spectrum which probably arises from instabilities in the disk . the outbursts do not appear to display the same variability pattern ; moreover , they show similar temporal behaviors in the hard and soft states , which correspond to different states of the disk . therefore , they are unlikely to originate due to an intrinsic disk effect . the most straightforward suggestion , and the one which we adopt as a working hypothesis , is that this could be some rare eruptive phenomenon in the donor wind ejection . the typical dynamical timescale for standard disk accretion in the case of cyg x-1 is much longer than the duration of the outbursts , so that any fluctuations in the donor ejection rate would be dilated by up to a day or more ( bisnovaty - kogan , private communication , 2002 ) . direct wind accretion , on the other hand , has a dynamical timescale @xmath32 s , but a shorter timescale can arise from instabilities in the accreting flow ( illarionov , private communication , 2002 ) . other interpretations are possible . for example , the outbursts could be attributed to the recently discovered jet of cyg x-1 ( stirling et al . 2001 ) and their recurrence could be explained by its precession ( romero et al . the outbursts reported here have durations comparable to the period of a low earth - orbiting spacecraft , making them difficult to detect and follow from experiments aboard such spacecraft , but relatively easy for experiments which are far from earth and do not undergo occultation and orbital background variations . indeed , our observations of 990421a show that it continues well beyond the point at which it was earth - occulted to batse , and our observations of 990421b indicate that it commenced several hundred seconds before it rose on batse ( stern et al . these observations point to a new use for the ipn , namely tracking long , intense flares from galactic transients . the data from a single experiment which has little or no directional and/or spectral information are easily confused with solar x - ray and particle events , which explains why it has taken so long to determine the origin of some of the outbursts presented here . however , confirmation by a second spacecraft solves this problem and gives an annulus of position which in many cases may be sufficient to determine the origin of the emission . for several outbursts , the batse observations alone yield source directions which are only accurate to 17@xmath33 , leaving the possibility that the source could have been cygnus x-3 . however , relatively small error ellipses may be obtained from multiple observations , and our localizations rule this possibility out conclusively . the histories of cygnus x-1 and grbs have been curiously intertwined over the decades . in the early days of x - ray astronomy , the use of interplanetary spacecraft was suggested to localize sources with rapid time variations such as cyg x-1 ( giacconi 1972 ) . although , to our knowledge , such measurements were never carried out on persistent x - ray sources , today the technique is the basis of the ipn , and the present observations demonstrate the feasibility of this suggestion . later , mason et al . ( 1997 ) pointed out that bursts from cyg x-1 could appear in the batse database ; batse has indeed triggered many times on this source . some of the long outbursts presented here have time histories which , if compressed in time , would be virtually impossible to distinguish from those of grbs , and their spectra are hard . these similarities suggest that accretion onto a black hole , which is believed to power both cyg x-1 and grbs albeit under very different circumstances , may manifest itself in similar ways in very different settings . support for the _ ulysses grb experiment is provided by jpl contract 958056 , and for konus-_wind by a russian aviation and space agency contract and rfbr grant n 03 - 02 - 17517 . we are grateful to al levine and the asm / rxte team for quick - look results on cygnus x-1 , and to andrei illarionov for useful discussions . this research has made use of the simbad database , operated at cds , strasbourg , france . _ _ terekhov , m. , aptekar , r. , frederiks , d. , golenetskii , s. , ilinskii , v. , and mazets , e. , 1998 , in aip conf . 428 , gamma - ray bursts - 4th huntsville symposium , eds . c. meegan , r. , preece , & t. koshut ( new york : aip ) , 894 950110 & 18600 & 27500 & _ ulysses , konus , batse & hard & 0.37 + 950325 & 14400 & 28000 & _ ulysses , konus , batse & hard & 0.57 + 990421a & 54510 & 4870 & _ ulysses , konus , batse & hard & 0.38 + 990421b & 63100 & 1360 & _ ulysses , batse & hard & 0.40 + 020224 & 54600 & 10000 & _ ulysses , konus & soft & 0.10 + 020331 & 35925 & 910 & _ ulysses , konus & soft & 0.31 + 030212 & 65000 & 5800 & _ ulysses , konus & hard & 0.16 _ _ _ _ _ _ _ 950110 & a & 0.92@xmath340.08 & 1.24@xmath340.05 & 111@xmath3410 & 85@xmath343 + & b & 0.93@xmath340.12 & 1.45@xmath340.07 & 133@xmath3422 & 73@xmath344 + & c & 1.07@xmath340.15 & 1.81@xmath340.08 & 452@xmath34218 & 84@xmath3417 + & a+b+c & 0.83@xmath340.06 & 1.50@xmath340.04 & 162@xmath3416 & 82@xmath343 + 950325 & a & 0.97@xmath340.09 & 1.26@xmath340.05 & 112@xmath3411 & 82@xmath343 + & b & 0.88@xmath340.23 & 1.24@xmath340.15 & 112@xmath3430 & 85@xmath349 + & b & 1.25@xmath340.30 & 1.36@xmath340.14 & 137@xmath3441 & 87@xmath3411 + & c & 0.61@xmath340.12 & 1.48@xmath340.11 & 156@xmath3444 & 81@xmath349 + & d & 0.94@xmath340.47 & 1.80@xmath340.26 & 163@xmath34128 & 33@xmath3419 + & a+c+d & 0.67@xmath340.07 & 1.44@xmath340.06 & 133@xmath3417 & 75@xmath344 + 990421a & a & 1.35@xmath340.92 & 1.20@xmath340.39 & 87@xmath3448 & 69@xmath345 + & b & 4.83@xmath340.94 & 1.83@xmath340.12 & 434@xmath34281 & 74@xmath3420 + & c & 9.88@xmath340.74 & 1.63@xmath340.05 & 303@xmath3454 & 113@xmath348 + & d & 3.08@xmath340.53 & 1.33@xmath340.10 & 111@xmath3419 & 75@xmath343 + & a+b+c+d & 4.24@xmath340.41 & 1.52@xmath340.06 & 156@xmath3420 & 72@xmath342 + 020224 & a & 2.28@xmath341.29 & 1.10@xmath340.34 & 63@xmath3421 & 57@xmath343 + & b & 0.48@xmath340.40 & 0.89@xmath340.52 & 64@xmath3432 & 71@xmath342 + & c & 2.73@xmath340.47 & 1.44@xmath340.11 & 121@xmath3423 & 68@xmath342 + & a+b+c & 2.38@xmath340.44 & 1.29@xmath340.11 & 88@xmath3413 & 62@xmath341 + 020331 & a & 57@xmath345 & 2.50@xmath340.08 & & + & b & 155@xmath349 & 2.60@xmath340.05 & & + & a+b & 107@xmath345 & 2.55@xmath340.04 & & + 030212 & a & 0.93@xmath340.47 & 1.31@xmath340.30 & 90@xmath3437 & 61@xmath342 lccccc 950110 & 21712 - 46215 & @xmath35 & 2.4 & @xmath36 & @xmath37 + 950325 & 22331 - 42635 & @xmath38 & 1.3 & @xmath39 & @xmath40 + 990421a & 54514 - 56613 & @xmath41 & 3.8 & @xmath42 & @xmath43 + 020224 & 54609 - 64583 & @xmath44 & 3.7 & @xmath45 & @xmath46 + 020331 & 35926 - 36835 & @xmath47 & 2.4 & @xmath48 & @xmath49 + 030212 & 64982 - 70775 & @xmath41 & 1.6 & @xmath50 & @xmath51 +

we present interplanetary network localization , spectral , and time history information for 7 episodes of exceptionally intense gamma - ray emission from cygnus x-1 . the outbursts occurred between 1995 and 2003 , with durations up to @xmath028000 seconds . the observed 15 - 300 kev peak fluxes and fluences reached @xmath1 respectively . by combining the triangulations of these outbursts we derive an @xmath0 1700 square arcminute ( 3 @xmath2 ) error ellipse which contains cygnus x-1 and no other known high energy sources . the outbursts reported here occurred both when cyg x-1 was in the hard state as well as in the soft one , and at various orbital phases . the spectral data indicate that these outbursts display the same parameters as those of the underlying hard and soft states , suggesting that they represent another manifestation of these states .

it originates from failure in union of maxillary and mandibular prominences of first brachial arch during 7 embryonic week . we report a case of bilateral macrostomia ( bilateral lip cleft ) in a female newborn as a sole entity without other skeletal and facial deformities . the cleft was repaired by a simple linear triangular flap using extra oral landmarks to locate lip commissures . commissural repair through a linear flap can result in minimal visible scar with satisfying results in both esthetics and functional aspects . macrostomia or lateral lip cleft , which is known as tessier cleft type 7 , is one of the rarest facial anomalies . its occurrence is reported 1 in 225,000 or 0.02% of all live births and constitutes about 0.3% to 1% of all facial clefts . the anomaly may be found as a part of syndromes like oto - mandibular dysostosis , hemifacial microsomia , treacher - collins , goldenhar , or in conjunction with additional facial symptoms such as preauricular tags , zygomatic arch deficiency , deformities in different mandibular parts such as ramus , condyle , or coronoid process , or ear anomalies ( deformities in external , middle or inner parts ) , and other facial clefts such as tessier [ 25 ] . the embryonic origin of lateral lip cleft may be related to the 7 embryonic week , when the maxillary and mandibular processes of first branchial arch merge laterally to fuse in a posterior to anterior manner and construct the corners of mouth and cheeks . it is also claimed to be a post - merging anomaly due to considerable clinical variability in expression . the manifestations of lateral facial cleft may vary from a slight commissural involvement and macrostomia , that sometimes remains undiagnosed specially when combines with other facial anomalies to a gross combination of soft and hard tissue extended from mouth to tragus . a 4-month female infant was referred to mofid pediatric training hospital for correction of inferiorly rotated bilateral transverse lip cleft ( fig . the main complaints of parents were unacceptable facial appearance as well as disturbed oral functions specially sucking and breastfeeding abilities , and nose vomiting . the baby was a full term , normocephal female , with normal fontanels and auditory meatus without any evidence of skin abnormalities . the treatment decision made based on the clinical findings relying on the fact that bilateral lip cleft is a soft tissue entity without involving the bony components . the position of new commissures was determined by the point that vermelion texture changes from normal mucosa to cleft mucosa . correctional surgery performed on lip with simple linear triangular incision and full thickness flap in lower one third of the lip . after releasing the muscle from skin and mucosa , the cleft area was repaired in three layers of muscular , mucousal and skin tissue mucosal layer was sutured to muscle by interrupted sutures . finally the skin layer was repaired by simple linear inferiorly rotated triangular incision . the cleft appearance before surgery the facial appearance immediately after surgery ( fig . transverse lateral facial clefts are usually found unilaterally most often in males . bilateral inferiorly rotated cleft is a rare occurrence . skin and facial deformities are usually absent in bilateral types , that is in concordance with our findings [ 3 , 11 ] . the mother reported an uneventful pregnancy and labor without any exposure to medications or radiation ; however , the parents were relatives and a familial history of other types of clefts was present in this case that intensifies the genetics as the most probable etiological factor . a lateral cleft is considered as a multifactorial congenital anomaly ( interactions of several genes and environmental factors ) , or postzygotic mutation . various mutations may change in the neural crest or surface proteins which may lead to lateral facial clefts . it may also be attributed to disruption in stapedeial artery blood flow during the rapid embryonic growth and development . esthetics as well as function , especially in subjects without other anomalies , is a great concern . surgery should be done in young age to avoid unwanted anxiety and psychological impacts on both child and family as well as correcting sialorrhea , speech problems and compromised chewing ability . the aim of surgery is to place symmetric lip commissures with normal contour and minimally visible scar . reconstruction of orbicularis oris is the key of normal appearance of lip commissure . in this case cleft in contrast to superiorly or middle rotated types , inferiorly rotated lateral lip cleft does not involve the bony component , however separation of the muscles such as the risorious and depressor anguli oris can be observed . in repair process reconstruction of commissural initially z plasty were commonly performed , however it has the shortcomings such as of suboptimal esthetics . other techniques such as simple linear flap , w - plasty , and triangular flap which was the one used in this patient have shown good results . in point of scar contraction in linear incision , it should be noted that precise repair of orbicularis oris muscle is the key point in transverse lip clefts which restores muscular balance and prevents inferior displacement of the commissures . a well repaired orbicularis oris would provide a medial dynamic counterforce to lateral displacement resulting from contractile force of the linear scar . bilateral macrostomia as a rare soft tissue deformity can be repaired successfully with minimally visible scar by simple linear triangular flap . it seems that z - plasty or w - plasty techniques are unnecessary in repairung transverse cleft lips

backgroundmacrostomia as a rare facial deformity is classified among facial clefts . it originates from failure in union of maxillary and mandibular prominences of first brachial arch during 7th embryonic week.case presentationwe report a case of bilateral macrostomia ( bilateral lip cleft ) in a female newborn as a sole entity without other skeletal and facial deformities . the cleft was repaired by a simple linear triangular flap using extra oral landmarks to locate lip commissures . patient was followed through a six - month period . acceptable results were gained in mouth appearance as well functional aspects.conclusioncommissural repair through a linear flap can result in minimal visible scar with satisfying results in both esthetics and functional aspects .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Coal Energy Research, Development, and Demonstration Act of 2003''. SEC. 2. DEFINITIONS. For purposes of this Act: (1) Cost and performance goals.--The term ``cost and performance goals'' means the cost and performance goals established under section 101(a). (2) Secretary.--The term ``Secretary'' means the Secretary of Energy. TITLE I--COAL RESEARCH AND DEVELOPMENT SEC. 101. COAL AND RELATED TECHNOLOGIES PROGRAMS. (a) Establishment of Cost and Performance Goals.-- (1) In general.--The Secretary shall perform an assessment that identifies cost and performance goals, for achievement in 2007, 2015, and the years after 2020, for technologies that would permit the continued cost-competitive use of coal for electricity generation, as chemical feedstocks, and as transportation fuel. (2) Consultation.--In establishing the cost and performance goals under this subsection, the Secretary shall-- (A) consider activities and studies undertaken by industry in cooperation with the Department of Energy in support of the assessment performed under paragraph (1); and (B) consult with interested entities, including coal producers, industries using coal, organizations to promote coal and advanced coal technologies, environmental organizations, and organizations representing workers. (3) Timing.--The Secretary shall-- (A) not later than 120 days after the date of enactment of this Act, issue a set of draft cost and performance goals for public comment; and (B) not later than 180 days after the date of enactment of this Act, after taking into consideration any public comments received, transmit to Congress the final cost and performance goals. (b) Study.-- (1) In general.--Not later than 1 year after the date of enactment of this Act, and once every 2 years thereafter through 2016, the Secretary, in cooperation with other appropriate Federal agencies, shall conduct and transmit to the Congress a study to-- (A) identify technologies that, by themselves or in combination with other technologies, may be capable of achieving the cost and performance goals; (B) assess the costs that would be incurred by, and the period of time that would be required for, the development and demonstration of technologies that, by themselves or in combination with other technologies, contribute to the achievement of the cost and performance goals; (C) develop recommendations for technology development programs, which the Department of Energy could carry out in cooperation with industry, to develop and demonstrate technologies that, by themselves or in combination with other technologies, achieve the cost and performance goals; and (D) develop recommendations for additional authorities required to achieve the cost and performance goals and review and recommend changes, if any, to those cost and performance goals if the Secretary determines that such changes are necessary as a result of ongoing research, development, and demonstration of technologies. (2) Expert advice.--In carrying out this subsection, the Secretary shall give due weight to the expert advice of representatives of the entities described in subsection (a)(2)(B). SEC. 102. PRODUCTION AND GENERATION OF COAL-BASED POWER. (a) In General.--The Secretary shall carry out a technology research, development, and demonstration program to facilitate production and generation of coal-based power through methods and equipment under-- (1) this title; (2) the Federal Nonnuclear Energy Research and Development Act of 1974 (42 U.S.C. 5901 et seq.); (3) the Energy Reorganization Act of 1974 (42 U.S.C. 5801 et seq.); and (4) title XVI of the Energy Policy Act of 1992 (42 U.S.C. 13381 et seq.). (b) Conditions.--The program described in subsection (a) shall be designed to achieve the cost and performance goals. SEC. 103. AUTHORIZATION OF APPROPRIATIONS. (a) In General.--There are authorized to be appropriated to the Secretary $200,000,000 for fiscal year 2005, $210,000,000 for fiscal year 2006, and $220,500,000 for fiscal year 2007, to remain available until expended, for carrying out the program under section 102, which may include-- (1) innovations for existing plants; (2) integrated gasification combined cycle; (3) advanced combustion systems; (4) turbines for synthesis gas derived from coal; (5) carbon capture and sequestration research and development; (6) coal-derived transportation fuels and chemicals; (7) solid fuels and feedstocks; (8) advanced coal-related research; and (9) advanced separation technologies. (b) Limit on Use of Funds.--The Secretary shall not use funds appropriated under this section until 30 days after the Secretary has transmitted to the Congress a report describing the proposed use of such funds and containing a plan that includes-- (1) a detailed description of how proposals, if any, will be solicited and evaluated, including a list of all activities expected to be undertaken; (2) a detailed list of technical milestones for each coal and related technology that will be pursued; and (3) a description of how the programs for which such funds are authorized will be carried out so as to complement and not duplicate activities authorized under the Clean Coal Power Initiative authorized under title II. TITLE II--CLEAN COAL POWER INITIATIVE SEC. 201. PROJECT CRITERIA. (a) In General.--The Secretary shall provide funding under this title for coal energy generation projects that advance efficiency, environmental performance, and cost competitiveness well beyond the level of technologies that on a full scale are in operation or have been demonstrated as of the date of enactment of this Act. (b) Technical Criteria for Clean Coal Power Initiative.-- (1) Gasification.-- (A) Technologies.--In allocating the funds made available under section 204(a), the Secretary shall ensure that up to 80 percent of the funds are used for coal-based gasification technologies, including gasification combined cycle, gasification fuel cells, gasification coproduction, and hybrid gasification/ combustion projects. (B) Technical milestones.--The Secretary shall set technical milestones specifying emissions levels for projects funded under this paragraph. The milestones shall be designed to increasingly restrict emissions levels through the life of the program. The milestones shall be designed to achieve by 2020 coal gasification projects able-- (i) to remove 99 percent of sulfur dioxide; (ii) to emit no more than .05 lb of NO&lt;INF&gt;X&lt;/INF&gt; per million BTU; (iii) to achieve substantial reductions in mercury emissions; and (iv) to achieve a thermal efficiency of-- (I) 60 percent for coal of more than 9,000 Btu; (II) 59 percent for coal of 7,000 to 9,000 Btu; and (III) 50 percent for coal of less than 7,000 Btu. (2) Other projects.--For projects not described in paragraph (1), the Secretary shall set technical milestones specifying emissions levels. The milestones shall be designed to increasingly restrict emissions levels through the life of the program. The milestones shall be designed to achieve by 2010 projects able-- (A) to remove 97 percent of sulfur dioxide; (B) to emit no more than .08 lb of NO&lt;INF&gt;X&lt;/INF&gt; per million BTU; (C) to achieve substantial reductions in mercury emissions; and (D) except as provided in paragraph (4), to achieve a thermal efficiency of-- (i) 45 percent for coal of more than 9,000 Btu; (ii) 44 percent for coal of 7,000 to 9,000 Btu; and (iii) 40 percent for coal of less than 7,000 Btu. (3) Consultation.--Before setting the technical milestones under paragraphs (1)(B) and (2), the Secretary shall consult with the Administrator of the Environmental Protection Agency and interested entities, including coal producers, industries using coal, organizations to promote coal or advanced coal technologies, environmental organizations, and organizations representing workers. (4) Existing units.--In the case of projects at coal- powered electricity generating facilities existing as of the date of enactment of this Act, in lieu of the thermal efficiency requirements set forth in paragraph (1)(B)(iv) and (2)(D), the projects shall be designed to achieve an overall thermal efficiency improvement, compared to the efficiency of the unit as of the date of enactment of this Act, of not less than-- (A) 7 percent for coal of more than 9,000 Btu; (B) 6 percent for coal of 7,000 to 9,000 Btu; and (C) 4 percent for coal of less than 7,000 Btu. (5) Permitted uses.--In allocating amounts made available under this title, the Secretary may fund projects that include as part of the project the separation and capture of carbon dioxide. (c) Financial Criteria.--The Secretary shall not provide a funding award under this title unless the recipient has documented to the satisfaction of the Secretary that-- (1) the award recipient is financially viable without the receipt of additional Federal funding; (2) the recipient will provide sufficient information to the Secretary for the Secretary to ensure that the award funds are spent efficiently and effectively; and (3) a market exists for the technology being demonstrated or applied, as evidenced by statements of interest in writing from potential purchasers of the technology. (d) Financial Assistance.--The Secretary shall provide financial assistance to projects that meet the requirements of subsections (a), (b), and (c) and are likely to-- (1) achieve overall cost reductions in the utilization of coal to generate useful forms of energy; (2) improve the competitiveness of coal among various forms of energy in order to maintain a diversity of fuel choices in the United States to meet electricity generation requirements; and (3) demonstrate methods and equipment that are applicable to 25 percent of the electricity generating facilities that use coal as the primary feedstock as of the date of the enactment of this Act. (e) Federal Share.--The Federal share of the cost of a project funded under this title shall not exceed 50 percent. (f) Applicability.--No technology, or level of emission reduction, shall be treated as adequately demonstrated for purposes of any other statute solely by reason of the use of such technology, or the achievement of such emission reduction, by one or more facilities receiving assistance under this title, unless this title is specifically referenced in such statute. SEC. 202. REPORT. Not later than 1 year after the date of the enactment of this Act, and once every 2 years thereafter through 2012, the Secretary, in consultation with other appropriate Federal agencies, shall transmit to the Congress a report describing-- (1) the technical milestones set forth in section 201 and how those milestones ensure progress toward meeting the requirements of subsections (b)(1)(B) and (b)(2) of section 201; and (2) the status of projects funded under this title. SEC. 203. CLEAN COAL CENTERS OF EXCELLENCE. As part of the program authorized under this title, the Secretary shall award competitive, merit-based grants to universities for the establishment of Centers of Excellence for Energy Systems of the Future. The Secretary shall provide grants to universities that can show the greatest potential for advancing new clean coal technologies. SEC. 204. AUTHORIZATION OF APPROPRIATIONS. (a) Clean Coal Power Initiative.--Except as provided in subsection (b), there are authorized to be appropriated to the Secretary to carry out the activities authorized by this title $200,000,000 for each of the fiscal years 2005 through 2013, to remain available until expended. (b) Limit on Use of Funds.-- (1) Obligation of funds.--The Secretary is authorized to obligate the use of funds under this section prior to the fiscal year such funds are authorized for under subsection (a), subject to appropriations. (2) Report.--The Secretary shall transmit to the Congress a report describing the proposed use of funds which includes-- (A) a detailed assessment of whether the aggregate funding levels provided under subsection (a) are the appropriate funding levels for this title; (B) a detailed description of how proposals will be solicited and evaluated, including a list of all activities expected to be undertaken; (C) a detailed list of technical milestones for each technology that will be pursued; and (D) a detailed description of how the initiative under this title will avoid problems enumerated in General Accounting Office reports on the Clean Coal Technology Program, including problems that have resulted in unspent funds and projects that failed either financially or scientifically. (3) Use of funds.--The Secretary may not use funds appropriated under this section until 30 days have elapsed after receipt of the report under paragraph (2). (c) Applicability.--Subsection (b) shall not apply to any project selected before September 30, 2004.

Coal Energy Research, Development, and Demonstration Act of 2003 - Instructs the Secretary of Energy to: (1) perform an assessment that identifies cost and performance goals of technologies permitting continued cost-competitive use of coal for electricity generation, as chemical feedstocks, and as transportation fuel in 2007, 2015, and the years after 2020; and (2) implement a technology research, development, and demonstration program to facilitate production and generation of coal-based power through methods and equipment under specified Federal law.Prescribes technical criteria for a clean coal power initiative under which the Secretary shall fund coal energy generation projects that advance efficiency, environmental performance, and cost competitiveness well beyond the level of technologies that on a full scale are in operation or have been demonstrated to date.Instructs the Secretary to award competitive, merit-based grants to universities for the establishment of Centers of Excellence for Energy Systems of the Future.

SECTION 1. SHORT TITLE. This Act may be cited as the ``Trafficking Survivors Relief Act of 2017''. SEC. 2. FEDERAL EXPUNGEMENT FOR VICTIMS OF TRAFFICKING. (a) In General.--Chapter 237 of title 18, United States Code, is amended by adding at the end the following: ``Sec. 3772. Motion to vacate; expungement; mitigating factors ``(a) Definitions.--In this section-- ``(1) the term `child' means an individual who has not attained 18 years of age; ``(2) the term `covered offense'-- ``(A) includes any offense against the United States and any offense punishable under the laws of the District of Columbia; and ``(B) does not include-- ``(i) a crime of violence; or ``(ii) an offense, if a child was a victim of the offense; ``(3) the term `covered prisoner' means an individual who-- ``(A) was convicted of a noncovered offense before the date of enactment of this section; ``(B) was sentenced to a term of imprisonment for the noncovered offense; and ``(C) is imprisoned under such term of imprisonment; ``(4) the term `crime of violence' has the meaning given that term in section 16; ``(5) the term `eligible entity' includes-- ``(A) a legal aid society or legal services organization that provides indigent legal services; ``(B) a nonprofit organization that provides legal services to victims of trafficking; and ``(C) a public defender's office; ``(6) the terms `employee' and `officer' have the meanings given the terms in section 2105 of title 5; ``(7) the term `noncovered offense'-- ``(A) means an offense that is an offense against the United States or punishable under the laws of the District of Columbia; and ``(B) does not include an offense, if a child was a victim of the offense; and ``(8) the term `victim of trafficking' has the meaning given that term in section 103 of the Trafficking Victims Protection Act of 2000 (22 U.S.C. 7102). ``(b) Motions To Vacate Convictions or Expunge Arrests.-- ``(1) In general.-- ``(A) Convictions of covered offenses.--A person convicted of any covered offense (or an eligible entity representing such a person) may move the court which imposed the sentence for the covered offense to vacate the judgment of conviction if the covered offense was committed as a direct result of the person having been a victim of trafficking. ``(B) Arrests for covered offenses.--A person arrested for any covered offense (or an eligible entity representing such a person) may move the district court for the district and division embracing the place where the person was arrested to expunge all records of the arrest if the conduct or alleged conduct of the person which resulted in the arrest was directly related to the person having been a victim of trafficking. ``(C) Arrests for noncovered offenses.--A person arrested for any noncovered offense (or an eligible entity representing such a person) may move the district court for the district and division embracing the place where the person was arrested to expunge all records of the arrest if-- ``(i) the conduct or alleged conduct of the person which resulted in the arrest was directly related to the person having been a victim of trafficking; and ``(ii)(I) the person is acquitted of the noncovered offense; ``(II) the Government does not pursue or dismisses criminal charges against the person for the noncovered offense; or ``(III)(aa) the charges against the person for the noncovered offense are reduced to an offense that is a covered offense; and ``(bb) the person is acquitted of the covered offense, the Government does not pursue or dismisses criminal charges against the person for the covered offense, or any subsequent conviction of the covered offense is vacated. ``(2) Contents of motion.--A motion described in paragraph (1) shall-- ``(A) be in writing; ``(B) describe any supporting evidence; ``(C) state the offense; and ``(D) include copies of any documents showing that the movant is entitled to relief under this section. ``(3) Hearing.-- ``(A) Mandatory hearing.-- ``(i) Motion in opposition.--Not later than 30 days after the date on which a motion is filed under paragraph (1), the Government may file a motion in opposition of the motion filed under paragraph (1). ``(ii) Mandatory hearing.--If the Government files a motion described in clause (i), not later than 15 days after the date on which the motion is filed, the court shall hold a hearing on the motion. ``(B) Discretionary hearing.--If the Government does not file a motion described in subparagraph (A)(i), the court may hold a hearing on the motion not later than 45 days after the date on which a motion is filed under paragraph (1). ``(4) Factors.-- ``(A) Vacating convictions of covered offenses.-- The court shall grant a motion under paragraph (1)(A) if, after notice to the Government and an opportunity to be heard, the court finds, by a preponderance of the evidence, that-- ``(i) the movant was convicted of a covered offense; and ``(ii) the participation in the covered offense by the movant was a direct result of the movant having been a victim of trafficking. ``(B) Expunging arrests for covered offenses.--The court shall grant a motion under paragraph (1)(B) if, after notice to the Government and an opportunity to be heard, the court finds, by a preponderance of the evidence, that-- ``(i) the movant was arrested for a covered offense; and ``(ii) the conduct or alleged conduct which resulted in the arrest was directly related to the movant having been a victim of trafficking. ``(C) Expunging arrests for noncovered offenses.-- The court shall grant a motion under paragraph (1)(C) if, after notice to the Government and an opportunity to be heard, the court finds, by a preponderance of the evidence, that-- ``(i) the movant was arrested for a noncovered offense and the conduct or alleged conduct which resulted in the arrest was directly related to the movant having been a victim of trafficking; and ``(ii)(I) the person is acquitted of the noncovered offense; ``(II) the Government does not pursue or dismisses criminal charges against the person for the covered offense; or ``(III)(aa) the charges against the person for the noncovered offense are reduced to a covered offense; and ``(bb) the person is acquitted of the covered offense, the Government does not pursue or dismissed criminal charges against the person for the covered offense, or any subsequent conviction of that covered offense is vacated. ``(5) Supporting evidence.-- ``(A) Rebuttable presumption.--For purposes of this section, there shall be a rebuttable presumption that the movant is a victim of trafficking if the movant includes in the motion-- ``(i) a copy of an official record, certification, or eligibility letter from a Federal, State, tribal, or local proceeding, including an approval notice or an enforcement certification generated from a Federal immigration proceeding, that shows that the movant was a victim of trafficking, including a victim of a trafficker charged with a violation of chapter 77; or ``(ii) an affidavit or sworn testimony from a trained professional staff member of a victim services organization, an attorney, a member of the clergy, or a medical or other professional from whom the movant has sought assistance in addressing the trauma associated with being a victim of trafficking. ``(B) Other evidence.-- ``(i) In general.--For purposes of this section, in determining whether the movant is a victim of trafficking, the court may consider any other evidence the court determines is of sufficient credibility and probative value, including an affidavit or sworn testimony of the movant. ``(ii) Affidavit or sworn testimony of movant sufficient evidence.--The affidavit or sworn testimony of the movant described in clause (i) shall be sufficient evidence to vacate a conviction or expunge an arrest under this section if the court determines that-- ``(I) the affidavit or sworn testimony is credible; and ``(II) no other evidence is readily available. ``(6) Conviction or arrest of other persons not required.-- It shall not be necessary that any person other than the movant be convicted of or arrested for a covered offense before the movant may file a motion under paragraph (1). ``(7) Denial of motion.-- ``(A) In general.--If the court denies a motion filed under paragraph (1), the denial shall be without prejudice. ``(B) Reasons for denial.--If the court denies a motion filed under paragraph (1), the court shall state the reasons for the denial in writing. ``(C) Reasonable time to cure deficiencies in motion.--If the motion was denied due to a curable deficiency in the motion, the court shall allow the movant sufficient time for the movant to cure the deficiency. ``(8) Appeal.--An order granting or denying a motion under this section may be appealed in accordance with section 1291 of title 28 and section 3731 of this title. ``(c) Vacatur of Convictions.-- ``(1) In general.--If the court grants a motion to vacate a conviction under subsection (b), the court shall immediately vacate the conviction for cause, set aside the verdict and enter a judgment of acquittal, and enter an expungement order that directs that there be expunged from all official records all references to-- ``(A) the arrest of the person for the covered offense; ``(B) the institution of criminal proceedings against the person relating to the covered offense; and ``(C) the results of the proceedings. ``(2) Effect.--If a conviction is vacated under an order entered under paragraph (1)-- ``(A) the conviction shall not be regarded as a conviction under Federal law and the person for whom the conviction was vacated shall be considered to have the status occupied by the person before the arrest or the institution of the criminal proceedings related to such conviction; and ``(B) no alien may be removed, determined to be inadmissible, or lose any immigration benefit because of such conviction, arrest, or institution of criminal proceedings. ``(d) Expungement of Arrests.-- ``(1) In general.--If the court grants a motion to expunge an arrest under subsection (b), the court shall immediately enter an expungement order that directs that there be expunged from all official records all references to-- ``(A) the arrest of the person for the covered offense; ``(B) the institution of any criminal proceedings against the person relating to the covered offense; and ``(C) the results of the proceedings, if any. ``(2) Effect.--If an arrest is expunged under an order entered under paragraph (1)-- ``(A) the arrest shall not be regarded as an arrest under Federal law and the person for whom the arrest is expunged shall be considered to have the status occupied by the person before the arrest or the institution of the criminal proceedings related to such arrest, if any; and ``(B) no alien may be removed, determined to be inadmissible, or lose any immigration benefit because of arrest or institution of criminal proceedings, if any. ``(e) Mitigating Factors.-- ``(1) In general.--The court which imposed sentence for a noncovered offense upon a covered prisoner may reduce the term of imprisonment for the noncovered offense-- ``(A) upon motion by a covered prisoner, the Director of the Bureau of Prisons, or the court's own motion; ``(B) after notice to the Government; ``(C) after considering-- ``(i) the factors set forth in section 3553(a); ``(ii) the nature and seriousness of the danger to any person; and ``(iii) the community, or any crime victims; and ``(D) if the court finds, by a preponderance of the evidence, that the covered prisoner committed the noncovered offense as a direct result of the covered prisoner having been a victim of trafficking. ``(2) Rebuttable presumption.--For the purposes of this subsection, there shall be a rebuttable presumption that a covered prisoner is a victim of trafficking if the covered prisoner provides-- ``(A) a copy of an official record, certification, or eligibility letter from a Federal, State, tribal, or local proceeding, including an approval notice or an enforcement certification generated from a Federal immigration proceeding, that shows that the covered prisoner was a victim of trafficking, including a victim of a trafficker charged with a violation of chapter 77; or ``(B) an affidavit or sworn testimony from a trained professional staff member of a victim services organization, an attorney, a member of the clergy, or a medical or other professional from whom the covered prisoner has sought assistance in addressing the trauma associated with being a victim of trafficking. ``(3) Requirement.--Any proceeding under this subsection shall be subject to section 3771. ``(4) Particularized inquiry.--For any motion under paragraph (1), the Government shall conduct a particularized inquiry of the facts and circumstances of the original sentencing of the covered prisoner in order to assess whether a reduction in sentence would be consistent with this section. ``(f) Additional Actions by Court.--The court may, upon granting a motion under this section take such additional action as the court determines is appropriate. ``(g) Confidentiality of Movant.-- ``(1) In general.--A motion under this section and any documents, pleadings, or orders relating to the motion shall be filed under seal. ``(2) Information not available for public inspection.--No officer or employee may make any report, paper, picture, photograph, court file or other document, in the custody or possession of the officer or employee, that identifies the movant available for public inspection. ``(h) Applicability.--This section shall apply to any conviction or arrest occurring before, on, or after the date of enactment of this section.''. (b) Technical and Conforming Amendment.--The table of sections of chapter 237 of title 18, United States Code, is amended by adding at the end the following: ``3772. Motion to vacate; expungement; mitigating factors.''.

Trafficking Survivors Relief Act of 2017 This bill amends the federal criminal code to establish a process to vacate convictions and expunge arrests for criminal offenses committed by trafficking victims that directly result from or relate to having been a trafficking victim. A trafficking victim may file a motion: (1) to vacate a conviction for a nonviolent offense that does not include a child victim (i.e., under age 18); (2) to expunge records of an arrest for a nonviolent offense that does not include a child victim; or (3) to expunge records of an arrest for an offense that is violent or that includes a child victim, if the charges are reduced, dismissed, or disposed of.

SECTION 1. RECOGNITION AS CORPORATION AND GRANT OF FEDERAL CHARTER FOR NATIONAL AMERICAN INDIAN VETERANS, INCORPORATED. (a) In General.--Part B of subtitle II of title 36, United States Code, is amended by inserting after chapter 1503 the following new chapter: ``CHAPTER 1504--NATIONAL AMERICAN INDIAN VETERANS, INCORPORATED ``Sec ``150401. Organization. ``150402. Purposes. ``150403. Membership. ``150404. Board of directors. ``150405. Officers. ``150406. Nondiscrimination. ``150407. Powers. ``150408. Exclusive right to name, seals, emblems, and badges. ``150409. Restrictions. ``150410. Duty to maintain tax-exempt status. ``150411. Records and inspection. ``150412. Service of process. ``150413. Liability for acts of officers and agents. ``150414. Failure to comply with requirements. ``150415. Annual report. ``Sec. 150401. Organization ``The National American Indian Veterans, Incorporated, a nonprofit corporation organized in the United States (in this chapter referred to as the `corporation'), is a federally chartered corporation. ``Sec. 150402. Purposes ``The purposes of the corporation are those stated in its articles of incorporation, constitution, and bylaws, and include a commitment-- ``(1) to uphold and defend the Constitution of the United States while respecting the sovereignty of the American Indian, Alaska Native, and Native Hawaiian Nations; ``(2) to unite under one body all American Indian, Alaska Native, and Native Hawaiian veterans who served in the Armed Forces of United States; ``(3) to be an advocate on behalf of all American Indian, Alaska Native, and Native Hawaiian veterans without regard to whether they served during times of peace, conflict, or war; ``(4) to promote social welfare (including educational, economic, social, physical, cultural values, and traditional healing) in the United States by encouraging the growth and development, readjustment, self-respect, self-confidence, contributions, and self-identity of American Indian veterans; ``(5) to serve as an advocate for the needs of American Indian, Alaska Native, and Native Hawaiian veterans, their families, or survivors in their dealings with all Federal and State government agencies; ``(6) to promote, support, and utilize research, on a nonpartisan basis, pertaining to the relationship between the American Indian, Alaska Native, and Native Hawaiian veterans and American society; and ``(7) to provide technical assistance to the 12 regional areas without veterans committees or organizations and programs by-- ``(A) providing outreach service to those Tribes in need; and ``(B) training and educating Tribal Veterans Service Officers for those Tribes in need. ``Sec. 150403. Membership ``Subject to section 150406 of this title, eligibility for membership in the corporation, and the rights and privileges of members, shall be as provided in the constitution and by-laws of the corporation. ``Sec. 150404. Board of directors ``Subject to section 150406 of this title, the board of directors of the corporation, and the responsibilities of the board, shall be as provided in the constitution and bylaws of the corporation and in conformity with the laws under which the corporation is incorporated. ``Sec. 150405. Officers ``Subject to section 150406 of this title, the officers of the corporation, and the election of such officers, shall be as provided in the constitution and bylaws of the corporation and in conformity with the laws of the jurisdiction under which the corporation is incorporated. ``Sec. 150406. Nondiscrimination ``In establishing the conditions of membership in the corporation, and in determining the requirements for serving on the board of directors or as an officer of the corporation, the corporation may not discriminate on the basis of race, color, religion, sex, national origin, handicap, or age. ``Sec. 150407. Powers ``The corporation shall have only those powers granted the corporation through its articles of incorporation and its constitution and bylaws which shall conform to the laws of the jurisdiction under which the corporation is incorporated. ``Sec. 150408. Exclusive right to name, seals, emblems, and badges ``(a) In General.--The corporation shall have the sole and exclusive right to use the names `National American Indian Veterans, Incorporated' and `National American Indian Veterans', and such seals, emblems, and badges as the corporation may lawfully adopt. ``(b) Construction.--Nothing in this section shall be construed to interfere or conflict with established or vested rights. ``Sec. 150409. Restrictions ``(a) Stock and Dividends.--The corporation shall have no power to issue any shares of stock nor to declare or pay any dividends. ``(b) Distribution of Income or Assets.--(1) No part of the income or assets of the corporation shall inure to any person who is a member, officer, or director of the corporation or be distributed to any such person during the life of the charter granted by this chapter. ``(2) Nothing in this subsection shall be construed to prevent the payment of reasonable compensation to the officers of the corporation, or reimbursement for actual and necessary expenses, in amounts approved by the board of directors. ``(c) Loans.--The corporation shall not make any loan to any officer, director, member, or employee of the corporation. ``(d) No Federal Endorsement.--The corporation shall not claim congressional approval or Federal Government authority by virtue of the charter granted by this chapter for any of its activities. ``Sec. 150410. Duty to maintain tax-exempt status ``The corporation shall maintain its status as an organization exempt from taxation as provided in the Internal Revenue Code of 1986. ``Sec. 150411. Records and inspection ``(a) Records.--The corporation shall keep-- ``(1) correct and complete books and records of accounts; ``(2) minutes of any proceeding of the corporation involving any of its members, the board of directors, or any committee having authority under the board of directors; and ``(3) at its principal office, a record of the names and addresses of all members having the right to vote. ``(b) Inspection.--(1) All books and records of the corporation may be inspected by any member having the right to vote, or by any agent or attorney of such member, for any proper purpose, at any reasonable time. ``(2) Nothing in this section shall be construed to contravene the laws of the jurisdiction under which the corporation is incorporated or the laws of those jurisdictions within which the corporation carries on its activities in furtherance of its purposes within the United States and its territories. ``Sec. 150412. Service of process ``With respect to service of process, the corporation shall comply with the laws of the jurisdiction under which the corporation is incorporated and those jurisdictions within which the corporation carries on its activities in furtherance of its purposes within the United States and its territories. ``Sec. 150413. Liability for acts of officers and agents ``The corporation shall be liable for the acts of the officers and agents of the corporation when such individuals act within the scope of their authority. ``Sec. 150414. Failure to comply with requirements ``If the corporation fails to comply with any of the restrictions or provisions of this chapter, including the requirement under section 150410 of this title to maintain its status as an organization exempt from taxation, the charter granted by this chapter shall expire. ``Sec. 150415. Annual report ``(a) In General.--The corporation shall report annually to Congress concerning the activities of the corporation during the preceding fiscal year. ``(b) Submittal Date.--Each annual report under this section shall be submitted at the same time as the report of the audit of the corporation required by section 10101(b) of this title. ``(c) Report Not Public Document.--No annual report under this section shall be printed as a public document.''. (b) Clerical Amendment.--The table of chapters at the beginning of subtitle II of title 36, United States Code, is amended by insert after the item relating to chapter 1503 the following new item: ``1504. National American Indian Veterans, Incorporated..... 150401''.

Grants a federal charter to the National American Indian Veterans, Incorporated (a nonprofit corporation organized in the United States).

WASHINGTON — In the months before Osama bin Laden was killed, the Central Intelligence Agency ran a phony vaccination program in Abbottabad, Pakistan, as a ruse to obtain DNA evidence from members of Bin Laden’s family thought to be holed up in an expansive compound there, according to an American official. The vaccination program was set up as the C.I.A. was struggling to learn whether Bin Laden was hiding in the compound, and adds a new twist to the months of spy games that preceded the nighttime raid in early May that killed the Qaeda chief. It has also aggravated already strained tensions between the United States and Pakistan. The operation was run by a Pakistan doctor, Shakil Afridi, whom Pakistani spies have since arrested for his suspected collaboration with the Americans. Dr. Afridi remains in Pakistani custody, the American official said. Getting DNA evidence from the people hiding in the Abbottabad compound would have been a significant coup, because it would have allowed the C.I.A. to match the samples with DNA from other members of the Bin Laden family that are on file at the C.I.A. — providing the first hard evidence in years of his whereabouts. The American official said that the doctor managed to temporarily gain access to the compound, but that he never saw Bin Laden and was not successful in getting DNA samples from any Bin Laden family members. Obama administration officials have said publicly they were not sure whether Bin Laden was in Abbottabad when dozens of Navy Seals commandos stormed the house in May. The existence of the vaccination program was first reported by a British newspaper, The Guardian. A C.I.A. spokesman declined to comment. It is unclear how the C.I.A. first recruited Dr. Afridi to work for the United States. The Guardian reported that he used a team of nurses and other health workers to administer Hepatitis B vaccinations throughout Abbottabad, even starting the program on poor fringes of the town to maintain a low profile. Pakistani military and intelligence operatives were furious about the American raid that killed Bin Laden, and relations between the United States and Pakistan have only plummeted since. Pakistani officials have suggested that they might use troops to repel another incursion into Pakistan, and many American officials believe that Pakistan seems more concerned with hunting C.I.A. informants than with finding Qaeda operatives. American officials said they planned to suspend as much as $800 million worth of military aid to Pakistan — a move partly designed to chasten Islamabad for expelling American military trainers — and several influential American lawmakers have suggested attaching more strings to the billions of dollars sent each year to Pakistan. Also at stake is the C.I.A.’s armed drone program, which has carried out hundreds of strikes in Pakistan in recent years and has killed several senior operatives from Al Qaeda and the Pakistani Taliban. Pakistan has threatened to expel C.I.A. operatives working on the drone program from a base in southern Pakistan, and the C.I.A. has set up contingency plans to run more flights from a base in eastern Afghanistan. American officials said that they have seen no hard evidence that Pakistani officials knew that Bin Laden was hiding in Abbottabad. However, American intelligence officials said that Bin Laden appeared to have been supported for years by militant groups with longstanding ties to Pakistan’s military spy agency. That agency arrested several suspected C.I.A. collaborators shortly after the Bin Laden raid, but according to the American official only the doctor who ran the vaccination program is still in custody. ||||| The CIA organised a fake vaccination programme in the town where it believed Osama bin Laden was hiding in an elaborate attempt to obtain DNA from the fugitive al-Qaida leader's family, a Guardian investigation has found. As part of extensive preparations for the raid that killed Bin Laden in May, CIA agents recruited a senior Pakistani doctor to organise the vaccine drive in Abbottabad, even starting the "project" in a poorer part of town to make it look more authentic, according to Pakistani and US officials and local residents. The doctor, Shakil Afridi, has since been arrested by the Inter-Services Intelligence agency (ISI) for co-operating with American intelligence agents. Relations between Washington and Islamabad, already severely strained by the Bin Laden operation, have deteriorated considerably since then. The doctor's arrest has exacerbated these tensions. The US is understood to be concerned for the doctor's safety, and is thought to have intervened on his behalf. The vaccination plan was conceived after American intelligence officers tracked an al-Qaida courier, known as Abu Ahmad al-Kuwaiti, to what turned out to be Bin Laden's Abbottabad compound last summer. The agency monitored the compound by satellite and surveillance from a local CIA safe house in Abbottabad, but wanted confirmation that Bin Laden was there before mounting a risky operation inside another country. DNA from any of the Bin Laden children in the compound could be compared with a sample from his sister, who died in Boston in 2010, to provide evidence that the family was present. So agents approached Afridi, the health official in charge of Khyber, part of the tribal area that runs along the Afghan border. The doctor went to Abbottabad in March, saying he had procured funds to give free vaccinations for hepatitis B. Bypassing the management of the Abbottabad health services, he paid generous sums to low-ranking local government health workers, who took part in the operation without knowing about the connection to Bin Laden. Health visitors in the area were among the few people who had gained access to the Bin Laden compound in the past, administering polio drops to some of the children. Afridi had posters for the vaccination programme put up around Abbottabad, featuring a vaccine made by Amson, a medicine manufacturer based on the outskirts of Islamabad. In March health workers administered the vaccine in a poor neighbourhood on the edge of Abbottabad called Nawa Sher. The hepatitis B vaccine is usually given in three doses, the second a month after the first. But in April, instead of administering the second dose in Nawa Sher, the doctor returned to Abbottabad and moved the nurses on to Bilal Town, the suburb where Bin Laden lived. It is not known exactly how the doctor hoped to get DNA from the vaccinations, although nurses could have been trained to withdraw some blood in the needle after administrating the drug. "The whole thing was totally irregular," said one Pakistani official. "Bilal Town is a well-to-do area. Why would you choose that place to give free vaccines? And what is the official surgeon of Khyber doing working in Abbottabad?" A nurse known as Bakhto, whose full name is Mukhtar Bibi, managed to gain entry to the Bin Laden compound to administer the vaccines. According to several sources, the doctor, who waited outside, told her to take in a handbag that was fitted with an electronic device. It is not clear what the device was, or whether she left it behind. It is also not known whether the CIA managed to obtain any Bin Laden DNA, although one source suggested the operation did not succeed. Mukhtar Bibi, who was unaware of the real purpose of the vaccination campaign, would not comment on the programme. Pakistani intelligence became aware of the doctor's activities during the investigation into the US raid in which Bin Laden was killed on the top floor of the Abbottabad house. Islamabad refused to comment officially on Afridi's arrest, but one senior official said: "Wouldn't any country detain people for working for a foreign spy service?" The doctor is one of several people suspected of helping the CIA to have been arrested by the ISI, but he is thought to be the only one still in custody. Pakistan is furious over being kept in the dark about the raid, and the US is angry that the Pakistani investigation appears more focused on finding out how the CIA was able to track down the al-Qaida leader than on how Bin Laden was able to live in Abbottabad for five years. Over the weekend, relations were pummelled further when the US announced that it would cut $800m (£500m) worth of military aid as punishment for Pakistan's perceived lack of co-operation in the anti-terror fight. William Daley, the White House chief of staff, went on US television on Sunday to say: "Obviously, there's still a lot of pain that the political system in Pakistan is feeling by virtue of the raid that we did to get Osama bin Laden, something the president felt strongly about and we have no regrets over." The CIA refused to comment on the vaccination plot.

– Cunning minds at the CIA devised a phony vaccination program in an effort to uncover Osama bin Laden's hiding place, a Guardian investigation has found. A regional health official was recruited to organize the vaccination drive in Abbottabad, beginning the program in a poorer part of town to make it appear more authentic. Agents aimed to get DNA from children in what turned out to be bin Laden's compound. The doctor managed to gain entry to the bin Laden compound but wasn't able to obtain DNA samples, a US official tells the New York Times. After the raid that killed the al-Qaeda leader, the doctor was arrested for collaborating with the Americans. He remains in Pakistani custody, and American authorities are concerned about his safety, says a US official.

the congenital gingival granular cell tumor ( cgct ) is rare and found mainly in the gingival mucosa , most commonly in the anterior maxillary alveolar ridge . this tumor , which is also known as congenital epulis , congenital myoblastoma or neumann 's tumor , is benign and does not recur or metastasize.[1 - 2 ] it appears at birth and occurs more frequently in females than in males . although the exact histogenesis of this tumor is unknown , it is thought to originate from epithelial , undifferentiated mesenchymal cells , pericytes , fibroblasts , smooth muscle cells , and nerve - related cells.[4 - 5 ] management of cgcts includes surgical excision to facilitate feeding and respiration . the aim of this case report is to describe the treatment of a 2-day - old female patient who had a cgct . a two - day - old female patient was admitted to the department of pediatric dentistry at gulhane medical academy because of swelling of the gums in her upper jaw . intraoral examination revealed a polypoid lesion ( diameter 0.4 to 0.7 cm ) in the area of the maxillary right first primary molar ( figure 1 ) . the tumor had a smooth surface , was pedunculated , and was the same color as the surrounding oral mucosa . initial appearance of the tumor before surgical excision . following consultation with the maxillofacial surgery department , surgical excision under general anesthesia was planned to solve the infant 's feeding problems . the operation was performed on the 12th postnatal day and a biopsy specimen was sent for histopathological examination . the histopathological examination of the tumor confirmed that it was a cgct ( figure 2 ) . wound healing was observed at the two - week follow up , and there was no abnormality in the area of the surgery ( figure 3 ) . a : histologic sections showed subepithelial , unencapsulated but well - demarcated tumor ( 20xh&e ) . b : at higher magnification , it was seen that the tumor was composed of plump - polygonal shaped cells with large - pale granular cytoplasm and uniform small round nuclei . c : immunohistochemically , the tumor cells were negative for s-100 protein unlike its adult counterpart ( 100ximmunohistochemistery - s100 protein ) . cgcts , initially defined as " congenital epulis " by ernst christian neumann in 1871 , are rare benign mesenchymal tumors . it is reported that these tumors are found three times more frequently in the maxillary anterior region than in the mandibular region . cgcts often originate from the gingiva of the anterior maxillary alveolar ridge.[1,8 - 9 ] cgcts are seen most frequently in newborn females ( f / m 8:1 ) as a result of the stimulation of the intrauterine endogenous hormone . the tumor is often single but it has been reported to be multiple in 5 to 16% of cases . multiple tumors appear to occur mainly in the maxilla or mandible and have rarely been reported in the tongue . the diameter of the largest tumor reported was 7.5cm.[9 - 10 ] gctcs , in the clinical differential diagnosis , include teratomas , congenital dermoid cysts , congenital fibrosarcomas , hemangiomas , lymphangiomas , leiomyomas , rabdomyomas , heterotopic gastrointestinal cysts , congenital cystic choristomas , and congenital lipomas . cgcts appear as normal - colored mucosa , while hemangiomas and lymphangiomas have a red or dark blue area that is spongy on palpation . findings from palpation for fluctuation and doppler ultrasound may be used for definitive diagnosis of cgcts and cystic lesions . radiological examination for gctcs this is done mainly to differentiate gcgts from solid tissue tumors , especially to eliminate the suspicion of malignancy . in terms of histology , cgcts look like adult granular cell tumors . there is no mitosis and necrosis , but there is a network of capillaries among the tumor cells . it is thought that this tumor has undifferentiated mesenchymal cells , fibroblasts , myofibroblasts , histiocytes , schwann cells or odontogenic epithelial progenitor cells . when the tumor increases in size , it can cause feeding and respiration problems . therefore , surgical excision is required without delay . no recurrences have been observed in cases where a cgct has been completely removed . in our case , cgcts are rare benign tumors , and surgical resection is required to prevent feeding and respiration problems .

the congenital gingival granular cell tumor ( cgct ) , also as known as congenital epulis , is an unusual benign oral mucosal lesion in newborns . a two - day - old female patient was admitted to the department of pediatric dentistry at gulhane medical academy , ankara , turkey with her family , and an intraoral examination showed a cgct located in the buccal region of the maxillary right first primary molar . in this report , we present a case of cgct in a newborn .

in 1991 , 3i implant innovations ( biomet 3i inc . , fl ) aimed to construct wide - diameter implants with the larger diameter restorative platforms than standard implants . but , for some time , corresponding prosthetic components were unavailable ; hence , standard prosthetic abutments ( 4.1 mm diameter ) were used instead of abutments that matched the 5 and 6 mm implant diameters . the consequence of this form of treatment was an unintentional change of platform , the biological benefits and clinical effectiveness of the pls technique have been established by several studies.[37 ] in this article different aspects of platform switching concept will be discussed . crestal bone loss , biologic width , and stress distribution in this concept will be comprehensively reviewed . in the studies on pls , including data with a follow - up period of 4169 months , the documented bone loss varies between 0.05 and 1.4 mm [ table 1].[235724 ] investigations regarding crestal bone loss of platform switching ( pls ) and nonplatform switched ( npls ) implants crestal bone loss is a major criterion for implant success , which includes the evaluation of crestal bone level changes over time.[2527 ] this has been the initial diagnostic instrument used to depict periimplant states . albrektsson et al . , lang et al . , and roos et al . , determined that a successful implant is defined in terms of marginal bone loss around an implant restoration , with no more than 1.5 mm during the first year and no more than 0.2 mm during each succeeding year . bone resorption around the implant neck is frequently observed after loading by a reduction in bone dimension , both horizontally and vertically , and appears to depend on both biological and mechanical factors , such as surgical trauma to the periosteum , characteristics of the implant neck design , location of the implant / abutment joint , micromovements of the implant , and prosthetic components , the size of the microgap between the implant and the abutment , bacterial colonization of the implant sulcus , biologic width , and imbalance in the host parasite equilibrium . cappiello et al . , in a clinical and radiographic prospective study showed that pls decreased bone resorption to 0.95 mm compared to 1.67 mm in the control group . prosper et al . , in the first randomized prospective study of 360 implants , compared expanded platforms versus cylindrical implants involving abutments of the same size , placed in 60 partially edentulous patients . the results showed lower amount of bone loss in the group with reduced platforms , with the preservation of up to 98.3% versus 66.1% after 12 months , and 97.2% versus 53.3% after 2 years for two groups respectively . several controlled clinical trials have shown that implants with pls had significantly less bone resorption compared with traditional matching implant abutment connection . established a relationship between the extent of pls and the amount of marginal bone loss for the first time . wagenberg and froum in a prospective study evaluated implant survival , and crestal bone levels around implants that used the pls concept and followed for a minimum of 11 years . seventy - one of the 94 implants ( 75.5% ) showed no bone loss on the mesial aspect , and 67 implants ( 71.3% ) showed no bone loss on the distal aspect . this is the longest follow - up to a prospective investigation of platform - switched implants and confirms the concept for preservation of crestal bone levels . the beneficial effect of pls on bone loss in immediate loading or placement studies remains controversial , because most studies do not have the control group . crespi et al . , revealed the influence of pls on crestal bone level changes at 1 , 3 , 6 , 12 , and 24 months . implants with pls ( n=30 ) , and external hexagon ( n=34 ) , were positioned immediately after tooth extraction and were loaded immediately . results showed no differences in bone level changes between pls , and conventional external - hexagons implants after 24 months . canullo et al . , evaluated bone level response around single , immediately placed and provisionalized pls implants . the mean follow - up period was 25 months and the average bone resorption level in the pls group ( 0.30.16 mm ) was smaller than that in the non - pls group ( 1.100.35 mm ) , and this difference was statistically significant ( p<0.005 ) . this biologic soft - tissue coats the implant supporting bone in a 3 to 4 mm wide zone . cochran et al . , and hermann et al . , were reported preimplant histometric outcomes and confirmed the presence of biologic width . this is true for any implant patients , whether on one - stage or in two - stage placement protocols on two - piece implants . tarnow et al . , showed that not only this width progresses apically , but also a lateral component of the biologic width exists around implants . this lateral component varies from 1.04 mm when two adjoining implants are placed less than 3 mm apart to 0.45 mm when the implants are placed more than 3 mm apart . inhibition of bone resorption is an important factor in achieving good esthetic results in the maxillary aesthetic zone and providing sufficient bone to support the implants . vertical bone resorption , which often extends 12 mm below the implant - abutment interface , may lead to a possible biomechanical disadvantage by increasing stress values at the bone - implant interface . horizontal bone loss may cause resorption of the buccal plate , loss of the interproximal bone peak , and loss of support for the adjacent interimplant papilla . results from lazzara and porter showed the history and importance of the microgap and the reconstruction of a biologic width around dental implants . the saucerization procedure leads to wound healing by means of lack of bone apposition , and fibrous scar tissue formation . this zone of connective tissue is infiltrated by chronic inflammatory cells and is always present around the implant abutment junction ( iaj ) of two - piece implant systems . ericsson et al . , have identified an inflammatory connective tissue ( ict ) zone infiltrate in the junctional epithelium of the periimplant mucosa . this inflammatory zone developed vertically for about 0.50.75 mm coronal and 0.50.75 mm apical to the implant abutment junction ( iaj ) . an approximately 1 mm wide layer of healthy connective tissue separates the ict from bone . this tissue provides protection and reinforcement of the crestal bone , by prevention the passage of microorganisms . in an experimental study in dog , the thickness of this mucosal seal was approximately 3 mm and intentional reduction of this protective layer to 2 mm or less lead to greater crestal bone loss . luongo et al . , reported that at the iaj , it was possible to clearly distinguish a zone of ict infiltrate in which the presence of plasma cells and lymphocytes was detectible . a noteworthy finding was that this inflammatory infiltrate extended vertically for 0.35 mm coronal to the iaj along the healing abutment , while in the horizontal direction , it did not exceed the length of the implant with pls . rodriquez - ciurana et al . , indicated that the biologic width around the platform - switched implants are located more coronally than the biologic width around the nonplatform switched implants . in animal experiments becker et al . , could not differentiate the pls and control groups statistically but concluded that pls could prevent the apical down - growth of the barrier epithelium in 28 days . the pls technique causes the margin of the iaj inward , toward the central axis of the implant . the inward movement of the iaj is believed to shift the inflammatory cell infiltrate to the central axis of the implant and away from the adjacent crestal bone , which is thought of limiting crestal bone resorption . this may result in a reduced inflammatory effect within the surrounding soft tissue and crestal bone . consequently , ( i ) a biologic width dimension forms without an increase in loss of crestal bone around dental implants ; ( ii ) the relative impact of bacterial leakage at the microgap on bone remodeling around dental implants decreases ; and ( iii ) soft - tissue levels that helps to avoid esthetic deformities , phonetic problems , and food impaction preserves . several studies have described methods ( photoelastic analysis , strain gauge placement , finite - element analysis ( fea ) ) for evaluating the biomechanical advantages of the pls.[5259 ] maeda et al . , in a fea concluded that the pls configuration shifted the stress concentration away from the peri - implant marginal bone but increases the stress in the abutment or the abutment screw . canullo et al . , performed a 3d finite element analysis on three different implant abutment configurations : a 3.8 mm implant with a matching diameter abutment ( standard control design , scd ) , a 5.5 mm implant with matching diameter abutment ( wider control design , wcd ) , and a 5.5 mm implant with a 3.8 mm abutment ( experimental design , ed ) . their results showed that the ed configuration minimized the stresses at the implant / abutment interface region . pessoa et al . , in a computed tomography - based three - dimensional fea demonstrated that the platform - switched designs can be considered a valid treatment option , equivalent to the conventional matching diameter abutment implant configurations . pellizzer et al . , in a photoelastic analysis found no significant difference between wide - diameter and pls implants with respect to the magnitude of stress but stress concentration decreased in the cervical region of the platform - switching implant . using strain gages evaluated the effect of pls on strain developed around implants supporting mandibular overdenture . the results showed that the increasing amount of strain developed because decreasing the abutment size does not favor the use of pls in implant - supported mandibular overdentures . stress concentrations on pls implants are located at the center of the implant abutment joint ( at the level of the implant screw ) will be helpful in reducing crestal bone resorption . concerns exist about loss of implant papilla and exposing the metal collar at the implant shoulder in the esthetic zone.[6267 ] as a consequence , the pls technique has been developed to either preserve or regenerate the interimplant soft tissue and impede an unsightly metal display . in a situation in which limitation of the residual bone height , poor - quality bone , and narrow edentulous sectors exist and can not be resolved , an alternative approach , which may possibly be used to overcome these problems , is the pls technique . differences in interpretation of function of the pls technique have been noted in several studies . however , clinical advantages of the pls technique may be the cause of a reduction in the crestal bone loss and maintaining the counterpart soft tissue around the implant . therefore , pls can preserve soft and hard tissues and may provide better biological , mechanical , and esthetic outcomes . because of controversial results especially in immediate loading and animal studies , further modified research is needed to establish the mechanism and effect of the pls technique . therefore , essential changes in studies including using the control group for accurate interpretation of results and long - term observation , particularly through , randomized , prospective , multicenter trials with large numbers of participants and implants are necessary . the four common clinical conditions requiring a selective pls technique are as follows : where anatomic structures such as the sinus cavity , the nasal floor , the incisive canal , and the alveolar nerve limit the residual bone height.where implants must be placed less than 3 mm apart ( between 1.5 and 3 mm ) in narrow edentulous sectors.where using short implants and in atrophic areas.when achieving good esthetic results in the anterior maxilla is more important . where anatomic structures such as the sinus cavity , the nasal floor , the incisive canal , and the alveolar nerve limit the residual bone height . where implants must be placed less than 3 mm apart ( between 1.5 and 3 mm ) in narrow edentulous sectors . where using short implants and in atrophic areas . when achieving good esthetic results in the anterior maxilla is more important

the platform switching ( pls ) concept was introduced in the literature in 2005 . the biological benefits and clinical effectiveness of the pls technique have been established by several studies . in this article different aspects of pls concept are discussed . crestal bone loss , biologic width , and stress distribution in this concept are comprehensively reviewed . in this article the relative published articles from 1990 to 2011 have been evaluated by electronic search . because of controversial results especially in immediate loading and animal studies , further modified research is needed to establish the mechanism and effect of the pls technique . essential changes in studies including using the control group for accurate interpretation of results and long - term observation , particularly through , randomized , prospective , multicenter trials with large numbers of participants , and implants are necessary .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Law Enforcement Officers Safety Act of 2004''. SEC. 2. EXEMPTION OF QUALIFIED LAW ENFORCEMENT OFFICERS FROM STATE LAWS PROHIBITING THE CARRYING OF CONCEALED FIREARMS. (a) In General.--Chapter 44 of title 18, United States Code, is amended by inserting after section 926A the following: ``Sec. 926B. Carrying of concealed firearms by qualified law enforcement officers ``(a) Notwithstanding any other provision of the law of any State or any political subdivision thereof, an individual who is a qualified law enforcement officer and who is carrying the identification required by subsection (d) may carry a concealed firearm that has been shipped or transported in interstate or foreign commerce, subject to subsection (b). ``(b) This section shall not be construed to supersede or limit the laws of any State that-- ``(1) permit private persons or entities to prohibit or restrict the possession of concealed firearms on their property; or ``(2) prohibit or restrict the possession of firearms on any State or local government property, installation, building, base, or park. ``(c) As used in this section, the term `qualified law enforcement officer' means an employee of a governmental agency who-- ``(1) is authorized by law to engage in or supervise the prevention, detection, investigation, or prosecution of, or the incarceration of any person for, any violation of law, and has statutory powers of arrest; ``(2) is authorized by the agency to carry a firearm; ``(3) is not the subject of any disciplinary action by the agency; ``(4) meets standards, if any, established by the agency which require the employee to regularly qualify in the use of a firearm; ``(5) is not under the influence of alcohol or another intoxicating or hallucinatory drug or substance; and ``(6) is not prohibited by Federal law from receiving a firearm. ``(d) The identification required by this subsection is the photographic identification issued by the governmental agency for which the individual is employed as a law enforcement officer. ``(e) As used in this section, the term `firearm' does not include-- ``(1) any machinegun (as defined in section 5845 of the National Firearms Act); ``(2) any firearm silencer (as defined in section 921 of this title); and ``(3) any destructive device (as defined in section 921 of this title).''. (b) Clerical Amendment.--The table of sections for such chapter is amended by inserting after the item relating to section 926A the following: ``926B. Carrying of concealed firearms by qualified law enforcement officers.''. SEC. 3. EXEMPTION OF QUALIFIED RETIRED LAW ENFORCEMENT OFFICERS FROM STATE LAWS PROHIBITING THE CARRYING OF CONCEALED FIREARMS. (a) In General.--Chapter 44 of title 18, United States Code, is further amended by inserting after section 926B the following: ``Sec. 926C. Carrying of concealed firearms by qualified retired law enforcement officers ``(a) Notwithstanding any other provision of the law of any State or any political subdivision thereof, an individual who is a qualified retired law enforcement officer and who is carrying the identification required by subsection (d) may carry a concealed firearm that has been shipped or transported in interstate or foreign commerce, subject to subsection (b). ``(b) This section shall not be construed to supersede or limit the laws of any State that-- ``(1) permit private persons or entities to prohibit or restrict the possession of concealed firearms on their property; or ``(2) prohibit or restrict the possession of firearms on any State or local government property, installation, building, base, or park. ``(c) As used in this section, the term `qualified retired law enforcement officer' means an individual who-- ``(1) retired in good standing from service with a public agency as a law enforcement officer, other than for reasons of mental instability; ``(2) before such retirement, was authorized by law to engage in or supervise the prevention, detection, investigation, or prosecution of, or the incarceration of any person for, any violation of law, and had statutory powers of arrest; ``(3)(A) before such retirement, was regularly employed as a law enforcement officer for an aggregate of 15 years or more; or ``(B) retired from service with such agency, after completing any applicable probationary period of such service, due to a service-connected disability, as determined by such agency; ``(4) has a nonforfeitable right to benefits under the retirement plan of the agency; ``(5) during the most recent 12-month period, has met, at the expense of the individual, the State's standards for training and qualification for active law enforcement officers to carry firearms; ``(6) is not under the influence of alcohol or another intoxicating or hallucinatory drug or substance; and ``(7) is not prohibited by Federal law from receiving a firearm. ``(d) The identification required by this subsection is-- ``(1) a photographic identification issued by the agency from which the individual retired from service as a law enforcement officer that indicates that the individual has, not less recently than one year before the date the individual is carrying the concealed firearm, been tested or otherwise found by the agency to meet the standards established by the agency for training and qualification for active law enforcement officers to carry a firearm of the same type as the concealed firearm; or ``(2)(A) a photographic identification issued by the agency from which the individual retired from service as a law enforcement officer; and ``(B) a certification issued by the State in which the individual resides that indicates that the individual has, not less recently than one year before the date the individual is carrying the concealed firearm, been tested or otherwise found by the State to meet the standards established by the State for training and qualification for active law enforcement officers to carry a firearm of the same type as the concealed firearm. ``(e) As used in this section, the term `firearm' does not include-- ``(1) any machinegun (as defined in section 5845 of the National Firearms Act); ``(2) any firearm silencer (as defined in section 921 of this title); and ``(3) a destructive device (as defined in section 921 of this title).''. (b) Clerical Amendment.--The table of sections for such chapter is further amended by inserting after the item relating to section 926B the following: ``926C. Carrying of concealed firearms by qualified retired law enforcement officers.''. Speaker of the House of Representatives. Vice President of the United States and President of the Senate.

Law Enforcement Officers Safety Act of 2004 - Amends the Federal criminal code to authorize a qualified law enforcement officer carrying photographic governmental agency identification to carry a concealed firearm, notwithstanding any State or local law. Declares that this provision shall not be construed to supersede or limit the laws of any State that: (1) permit private persons or entities to prohibit or restrict the possession of concealed firearms on their property; or (2) prohibit or restrict the possession of firearms on any State or local government property, installation, building, base, or park. Defines "qualified law enforcement officer" as: (1) a current governmental agency law enforcement officer who is authorized to carry a firearm, who is not the subject of disciplinary action, who meets agency standards which require the employee to regularly qualify in the use of a firearm, and who is not under the influence of alcohol or another intoxicating or hallucinatory drug or substance; and (2) a retired law enforcement officer who retired in good standing from public agency service, who was regularly employed as a law enforcement officer for at least 15 years, who has a nonforfeitable right to agency retirement benefits, who has met the State's standards for training and qualification for active law enforcement officers to carry firearms during the most recent 12-month period, and who is not under the influence of alcohol or another intoxicating or hallucinatory drug or substance. Excludes from the definition of "firearm" any machine-gun, firearm silencer, and destructive device.

in the conventional picture of powerful extragalactic radio sources , the fanaroff - riley classification of an object @xcite is determined by the physics of the interaction between the kiloparsec - scale jets and the external medium . this is thought to take place in two very different ways . in the low - power fri sources there is a good deal of evidence ( see , e.g. , @xcite ; laing , these proceedings ) that the jets normally decelerate from relativistic to sub - relativistic speeds gradually over scales of 110 kpc . deceleration requires entrainment of external material in order that momentum should be conserved ( e.g. , * ? ? ? * ; * ? ? ? * ) and the jets on these scales are often apparently in direct contact with the external medium , so that direct jet - medium interactions are a possible mechanism for the deceleration . by contrast the jets in the more powerful frii sources remain relativistic , often out to scales of hundreds of kpc or more , until they decelerate abruptly ( i.e. , on scales that are much less than the length scale of the jet ) at a shock or shocks which involve the direct interaction of the jet not with the external medium but with the relativistic plasma that fills the lobes in which the jets are typically embedded , giving rise to the observed hotspots . ( for the purposes of this paper i will ignore the vast range of intermediate cases and peculiar objects that should really be accommodated in a scheme of this kind . ) one important _ similarity _ between the deceleration regions of the two types of source is that both are associated with particle acceleration . in the frii sources the detection of optical synchrotron emission from hotspots provided early evidence in favor of a beam model with local particle acceleration at the hotspots ( e.g. , @xcite ; @xcite ; but cf . the current probable detection of x - ray synchrotron emission from hotspots ( e.g. , @xcite , and see below ) makes it very hard to evade the conclusion that _ in situ _ particle acceleration at the hotspots is necessary . in the fris the situation is similar : optical jet detections meant that only models involving special geometries could evade the necessity for _ in situ _ particle acceleration ( e.g. , * ? ? ? * ; * ? ? ? * ) and these models are essentially completely ruled out by the x - ray data ( e.g. , * ? ? ? x - ray jet detections are common @xcite in powerful fri sources , so that it seems likely that particle acceleration is always associated with jet deceleration in fri jets . since we have no direct evidence for particle acceleration anywhere else in the large - scale structure of either class of radio source , these regions may be the place where the electron energy spectrum observed throughout the rest of the source is determined , and so it is important to understand the physical processes that are going on in the jets of fris and the hotspots of friis , using , if possible , insights gained from each class of source to understand the other . in this paper my focus will be on several outstanding problems in our understanding of the compact features of frii sources and what we can learn from them about jet - environment interaction , but i begin by briefly and subjectively reviewing what we can learn about jet - environment interaction and particle acceleration from the fris , the closest of which can be studied in much more detail than is possible for any frii . as discussed above , the 110 kpc - scale jets of fri sources have to interact with the environment in order to decelerate , although the present observational modelling of this process ( see laing , these proceedings ) does not allow us to extract the microphysics of the jet - environment interaction . fri jets should therefore be good places to look for evidence for jet - environment interactions . detailed radio and optical images of fri jets often show a ` knotty ' structure with many compact features the best - known example is the well - studied radio and optical jet of m87 ( e.g. , * ? ? ? the nature of the knots is not obvious . at least some appear to affect the whole jet ( e.g. , knot a in m87 ) which raises the possibility that they are hydrodynamical features such as internal shocks . if this were the case , there would be some analogy between these features and the hotspots of frii sources . however , bright compact features do not seem to be present in the radio emission of all fri jets , and x - ray observations of jets ( backed up in some cases by optical data ) often show smooth diffuse x - ray emission , which implies distributed particle acceleration , since the x - ray loss spatial scale ( defined as the speed of light multiplied by the synchrotron loss timescale for an electron radiating in the x - ray assuming a magnetic field strength of the order of the equipartition value ) is so short that x - ray synchrotron emission always tells us the location of _ current _ particle acceleration . the closest fri radio galaxy , centaurus a , provides an important testbed for models of jet deceleration and particle acceleration in fri jets . its distance ( 3.4 mpc ) means that the resolution of _ chandra _ is @xmath0 pc , comparable to the loss spatial scale . this can not be achieved in any more distant fri source . cen a s detailed x - ray and radio structure ( e.g. , @xcite ; @xcite ; see hardcastle et al . , these proceedings , for images ) shows complex , knotty structure in both the radio and x - ray images , with structure on scales that would be unresolved in any other fri jet . crucially , there is a good deal of small - scale dissimilarity between the x - ray and radio structures : there are bright radio knots that are poor x - ray sources while many of the compact x - ray sources have only faint or absent radio counterparts . in @xcite we used the dynamical information available from multiple vla images to argue that the x - ray bright knots are stationary while the radio - bright , x - ray - faint knots are moving down the jet at @xmath1 . this led us to argue that the compact x - ray bright features are localized shocks in the fluid flow , probably as a result of interaction with features from the external medium in the manner proposed by @xcite . this is the first direct association between the small - scale dynamics of an fri jet and the acceleration of high - energy particles . it is important to realise , though , that the emission in compact knots in the inner jet of cen a represents only a fraction of the total x - ray emission in the jet ( moreover , a fraction that clearly decreases with distance from the active nucleus ) . a second , diffuse component of x - ray emission is also present , and both from the luminosity function of knots @xcite and from the spectral differences between knots and diffuse emission ( hardcastle et al . , these proceedings & in prep . ) it seems likely that this has its origin in a different particle acceleration process . in some cases ( e.g. , * * ) we may be able to associate diffuse particle acceleration with hydrodynamical features affecting the whole jet , but in others we are not . it seems likely that this diffuse acceleration process is related to the bulk deceleration of the jet flow ( although we do not have evidence for bulk deceleration in cen a ) and it may well be the dominant process in other , more distant jets . both in cen a and in other jets with better - studied optical properties , the overall radio - through - x - ray spectra are inconsistent @xcite with simple continuous - injection models @xcite and the nature of the ` diffuse ' particle acceleration changes as a function of distance along the jet , with a decreasing x - ray / radio ratio and a steepening x - ray spectral index up till the point where the x - rays disappear . we do not as yet have any clear idea what the microphysics of this ` diffuse ' acceleration process are , but it is essential to understand it to make further progress in this area , and i will argue in the following section that we can no longer ignore it in frii hotspots as well . 6.5 cm -10pt 6.8 cm i begin this section by making a trivial point about nomenclature that is nevertheless important for what follows in the rest of the paper , particularly [ knots ] . this concerns when , and why , we refer to a compact feature as a hotspot rather than a ` jet knot ' . it is worth noting first of all that the definition of ` hotspot ' itself , as applied to radio maps , is not widely agreed on : for example , two widely cited papers on the detailed structure of frii sources , @xcite and @xcite , propose incompatible definitions . however , all definitions generally expect the hotspots to be found at the end of the source , since our theoretical expectation ( e.g. , * ? ? ? * ) is that these will be the ones associated with the jet termination . in particular , features that are part of a well - collimated jet are generally classed as ` jet knots ' . this division can be ambiguous some features near the end of jets but with clearly continuing well - collimated outflow are nevertheless usually referred to as hotspots ( e.g. , hotspot b of 3c390.3 : @xcite , and fig . [ 390.3 ] ) . the existence of multiple bright compact features associated with the jet termination ( see [ multiple ] , below ) is evidence that a definition of hotspots as directly equivalent to ` the location of jet termination ' is inadequate : in many places the jet does not seem to terminate at a single location or in a single step . we know that some features that would generally be classed as jet knots ( e.g. , knot f6 in 3c403 , @xcite ) produce optical and x - ray emission and are thus probably sites of particle acceleration , blurring the distinction between jet knots and hotspots further . this ambiguity can be and has been used in a self - serving way ( the present writer is as guilty of this as anyone else ) to ` define away ' problems with the picture that is being presented . a better definition would include some of the actual physics of the jet at the location of the compact feature , but this is hard since in many cases jets are faint or invisible the ` jet knot ' may be the only indication that a jet is present at all . in what follows i will use the traditional terminology , but the reader should be aware that the term ` jet knot ' is thus used to encompass a number of features with diverse characteristics and probably significantly different physical origins . is there a class of jet knots in friis that are related to direct environmental interactions with the jet , as we have argued in the case of centaurus a ? one place to look for such jet knots would be in sources where there is an independent suggestion of a jet / external medium interaction in the shape of ` jet - induced star formation ' . well - studied candidates for this process include 3c285 @xcite and 3c34 @xcite . however , there is little evidence in any of these sources that the interaction , if present , affects the jet itself . in 3c285 , for example , the images of @xcite show the jet to contain several knots , but none is spatially coincident with the position of the star - forming object that is believed to be interacting with the jet ( fig . [ 285 ] ) . thus not only are the knots in the jet not apparently related to environmental interactions , but the proposed environmental interactions do not apparently produce knots . one frii source where a jet - environment interaction apparently does affect the jet is 3c321 ( evans et al . , apj submitted ) . here an otherwise normal frii source has a jet that is disrupted downstream of a close passage between the jet and a companion galaxy , forming an fri - like jet structure on one side . the clear compact hotspots on the same side suggest that this is a temporary interaction that has been going on for only @xmath2 years . immediately adjacent to the companion galaxy is a compact jet knot . however , this knot is relatively faint and is not a source of any detectable optical or x - ray emission , unlike some other jet knots in friis : nor is the downstream ` fri - like ' jet an x - ray or optical source . the analogy between this source and the jet - medium interactions seen in fris is thus not particularly strong . the lack of any strong relationship between jet knots and environmental interactions lends support to a picture in which jet knots in friis have multiple possible origins . the regularly or quasi - regularly spaced knots seen in many jets ( see , e.g. , * ? ? ? * ) seem most likely to be related to internal shocks in the jet or to fluid dynamical instabilities . can the features conventionally classed as hotspots give us information about jet - environment interactions ? since , as discussed above , the ` environment ' of the jet at the jet termination point is the lobe or cocoon , it is clear that hotspots can in principle tell us about interactions with the lobe plasma : i discuss this in [ multiple ] . here , however , we can ask whether hotspots tell us anything about the _ external _ environment . we expect that the jet should terminate close to a boundary of the lobe or plume that the jet inhabits : the boundary is , of course , the location of the contact discontinuity between the external medium and the relativistic plasma that has previously passed through the jet . a consequence of this is that we do not expect to see hotspots that are physically in the centre of the lobe . a true hotspot ( as opposed to a jet knot ) seen at a distance from any lobe boundary is assumed to be there as a result of projection of an interaction between the jet and the front or back boundary of the lobe . a nice example of the jet / lobe boundary interaction is given by the jet termination in wide - angle tail radio galaxies @xcite : in these sources , which we argue are similar to frii radio galaxies with peculiarly - shaped lobes , compact hotspots are sometimes present and sometimes absent , and it is plausible that they are present only when the geometry of the plume and the current direction of the jet are such that the jet intersects the edge of the plume . here the interaction between the external environment and the ` cocoon ' plasma determines where the contact discontinuity is , and the intersection of the jet and the contact discontinuity , if present , determines where the hotspot is giving an indirect but important relationship between the hotspot and the external environment . other examples are provided by the ` bottle - neck ' hotspot structures seen in some frii radio galaxies , particularly at low radio luminosities ( see , e.g. , * ? ? ? * ) , which suggest an interaction between the lobe and a low - density region of the external medium . in general , though , while the _ location _ of hotspots can tell us something about the location and nature of the external medium , the detailed properties of hotspots do not . what then do the detailed properties of hotspots tell us ? i shall argue in this section that their complex structure and particle acceleration behavior are telling us about the nature of the interaction between the jet and its environment , the cocoon . the two traditional tools for study of hotspots have been monochromatic high - resolution ( polarimetric ) imaging , usually in the ghz - frequency radio , and broad - band spectral energy distributions usually based on data of comparatively low resolution . the first of these shows us that hotspots are not structurally simple : the terminations of jets rarely resemble the idealized axisymmetric structures seen in early ( and , regrettably , some current ) analytical and numerical modelling . this first became clear in the early days of high - resolution radio imaging when multiple hotspots started to be routinely detected in a given lobe ( e.g. , * ? ? ? observationally we try to distinguish between the most compact , ` primary ' hotspot in a lobe and the more diffuse ` secondary ' hotspot or hotspots , though sometimes this distinction is ambiguous . @xcite introduced the useful concept of a ` hotspot complex ' which covers a group of hotspots and the high - brightness emission that surrounds them . models for this complexity fall into two basic classes : those that seek to preserve a single true termination for the jet , such as the still popular dentist s drill model of @xcite or the disconnected - jet variant of @xcite , or those that propose that both the primary and secondary hotspot have a connection to the energy supply , so that the jet termination takes place in stages at the various hotspots , such as the splatter - spot model of @xcite or the jet - deflection model of @xcite . on the other hand , the radio through optical spectral energy distributions of hotspots ( primary and secondary ) have often been found to be in agreement with relatively simple models of first - order fermi particle acceleration at strong shocks ( e.g. , meisenheimer et al . 1989 ) , although even just based on seds some discrepancies were apparent ( see @xcite , in particular the prescient closing paragraph ) while the optically resolved synchrotron emission seen in some nearby hotspots also points to a distributed acceleration mechanism ( e.g. , * ? ? ? * ) . inclusion of x - ray information in principle would give important information about the location and nature of particle acceleration to the highest observable energies , as in the fri jets . however , the use of hotspot x - rays has been limited until recently because of uncertainty about the extent to which inverse - compton emission is responsible for the observed x - rays . in @xcite we argued that inverse - compton emission dominates only in the highest - luminosity hotspots , and that synchrotron emission is the only emission process that can produce detectable x - rays in the hotspots with the lowest radio luminosities ( i.e. , in the least powerful sources ) . low - power frii sources are therefore the best places to search for synchrotron x - rays that trace the locations of high - energy particle acceleration . our work in this area has been presented by @xcite , @xcite , @xcite and most recently @xcite . the key results can be summarized as follows : * x - ray emission associated with compact hotspots is common : the seds are usually consistent with a synchrotron origin for the x - rays and inconsistent with inverse - compton models . there are often , though not always , significant offsets on @xmath3 kpc scales between the peak of the emission in the x - ray and the peak in the x - ray , which is not expected in a simple synchrotron / shock acceleration model ( e.g. , figs [ 390.3 ] and [ 227 ] : see also erlund et al . , these proceedings ) . * x - ray emission is also often seen from diffuse regions around or behind the hotspots , with size scales @xmath4 kpc ( e.g. , fig . [ 390.3 ] ) . if this x - ray emission is also synchrotron and no other model is at all plausible then distributed particle acceleration must be taking place on these scales . this is very plausibly related to the distributed acceleration mechanism required in the fri jets . * some secondary hotspots are x - ray sources and so inferred to be sites of high - energy particle acceleration ( e.g. , fig . [ 227 ] ) . this implies that at least some secondary hotspots have ongoing access to a supply of energy , and are thus _ not _ produced by the simple dentist s drill mechanism . other hotspots are not detected in the x - ray and are therefore significantly less efficient at accelerating particles to the energies required for x - ray emission . we find that all x - ray - emitting hotspots are compact , but not all compact hotspots are x - ray sources . we interpret these complex hotspot behaviors in the context of models in which the hotspots are transient features created by the interaction of the lobe fluid with the jet . this process has been seen in many detailed simulations of light jets in which the assumption of axisymmetry has been removed ( e.g. , * ? ? ? the jet / lobe interaction causes the jet to move about in the head of the source on scales much less than the source lifetime . in this picture individual hotspots are telling us more about ` weather ' in the lobe than about source physics : in particular , we can not hope to understand the mechanisms of multiple hotspot formation by looking at any individual source , since the simulation shows that all the traditional processes may be capable of operating at different times . simulations that trace shocks and particle acceleration also give important clues to the interpretation of the x - ray emission . @xcite carried out three - dimensional mhd simulations that modeled the transport of relativistic electrons and of particle acceleration at shocks . they found that the interaction of the jet and the backflowing plasma at the head of the jet produced what they called a ` shock - web complex ' , `` a region of shocks of varying strengths and sizes spread throughout the source '' . even when there was a simple terminal shock , not all the jet material necessarily passed through it , and the terminal shock was not always the strongest shock in the system . while it is not clear that their simulations are perfectly matched to real radio sources , they are capable of producing simulated synchrotron images that show apparent clear discrete multiple hotspots @xcite and in these cases the particle acceleration is not necessarily well matched to the locations of the hotspots : hotspot locations in their model can have more to do with magnetic field amplification than with particle acceleration . the notion of a ` shock - web complex ' at the head of the jet could help to explain the diffuse x - ray emission now seen in the radio - bright but non - compact source head regions of a number of objects , as discussed above , while the idea that the particle acceleration region may not always be co - spatial with the observed radio hotspot might help to explain observed offsets . it seems very likely therefore that hotspots are indeed telling us about jet - environment interactions , but that the environment with which they are interacting is the cocoon , whose properties we can not probe directly . progress in this area may come from further numerical modelling or possibly from a better understanding of the nature of the cocoon plasma and the distribution of particles and magnetic field within it . the key results from the work described in this paper can be summarized as follows : * in fri jets , there is some direct evidence that some jet knots are due to environmental interaction , and we have an idea of the mechanism by which the interaction produces the knots . however , localized interactions are most likely not responsible for most of the high - energy particle acceleration in these jets . * in most frii jets there is little evidence that knots know about the environments , but there are counterexamples . ` jet knots ' in frii jets are a heterogeneous class and the terminology should be used cautiously . * the detailed properties of hotspots in friis are predominantly a result of interaction between the jet and the cocoon plasma , and there is much still to be understood about how this works . however , simple models of the locations and mechanisms of particle acceleration in these objects are now ruled out by a variety of observations . i thank my collaborators past and present who have worked with me on hotspot and jet radio x - ray observations , particularly ralph kraft , dan harris , diana worrall , mark birkinshaw , judith croston and dan evans . i also acknowledge generous financial support from the royal society . best , p.n . , longair , m.s . , & rttgering , h.j.a . 1997 , , 286 , 785 bicknell , g.v . 1984 , , 286 , 68 biretta , j.a . , & meisenheimer , k. 1993 , in rser h .- j . , meisenheimer k. , eds , jets in extragalactic radio sources , springer - 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i discuss the nature of ` hotspots ' and ` jet knots ' in the kpc - scale structures of powerful radio galaxies and their relationship to jet - environment interactions . i describe evidence for interaction between the jets of fri sources and their local environments , and discuss its relationship to particle acceleration , but the main focus of the paper is the hotspots of friis and on new observational evidence on the nature of the particle acceleration associated with them .

lung cancer is one of the most common types of cancer worldwide , it is highly aggressive and has a high rate of distant metastasis ( 1 ) . subcutaneous metastasis from lung cancer has been well described ( 2 ) ; however , reports of subcutaneous metastasis of lung cancer after three surgeries for recurrent brain metastasis are scarce . we herein report a rare case of subcutaneous metastasis from pulmonary adenocarcinoma and provide a brief review of the relevant literature . a 49-year - old female patient was admitted to our hospital due to a fast - growing mass in the left temporal scalp at a craniotomy site ( fig . a routine magnetic resonance imaging ( mri ) revealed recurrent lesions in the left temporal and parietal lobes and a separate large nodular mass in the subcutaneous tissue coinciding with the site of the previous craniotomy ( fig . a lung computed tomography ( ct ) scan at another hospital revealed a 2.4-cm mass in the upper lobe of the left lung . the patient did not undergo surgery due to enlarged mediastinal lymph nodes , but was treated with radiosurgery ( 5 years ) and chemotherapy ( 2 years ) . the subsequent ct scan demonstrated no residual or recurrent adenocarcinoma in the lung . in march , 2013 , a routine mri scan at another hospital revealed brain metastases in the left temporal and parietal lobes . the patient underwent subtotal resection of the tumors and decompressive craniectomy at the first hospital of jilin university ( changchun , china ) . in may , 2014 and august , 2015 the patient suffered recurrent brain metastases in the left temporal lobe , which were resected . , the patient was admitted to our hospital due to a fast - growing mass in the left temporal scalp at the craniotomy site . the patient 's medical history was unremarkable , apart from her father having been a heavy smoker for 30 years . the laboratory test results for tumor markers were as follows : carcinoembryonic antigen , 191.6 ng / ml ( normal , < 3.4 ng / ml ) and carbohydrate antigen 153 , 38.03 u / ml ( normal , < 25.0 u / ml ) . peripheral blood cell counts , liver and renal function tests and hormonal levels were within the normal range . as the location of the mass corresponded to the site of the craniotomy , seeding was considered . total excision of the lesions in the left temporal and parietal lobes and the mass in the subcutaneous tissue was performed ( fig . 4 ) , the masses diffusely expressed thyroid transcription factor-1 ( ttf-1 ) and cytokeratin ( ck)7 , the ki-67 index was 25% , whereas villin , ck20 and wilms tumor-1 were negative . cutaneous metastasis is caused by primary cancer - derived cells that grow in the skin ( 3 ) . according to the published literature , the overall incidence of cutaneous metastasis is 2.95.3% ( 4 ) , and 112% in lung cancer ( 2,58 ) . cutaneous metastasis usually presents as solitary or multiple nodules sized 5 mm-10 cm that are firm , immobile and covered with normal skin . in the present case , the nodule was firm , relatively immobile , and of normal yellow color . when the primary tumor is an adenocarcinoma , other diagnoses such as melanoma and hematopoietic malignancies should be considered ( 9 ) . the patient in the present study had undergone multiple surgeries with subsequent complications associated with the surgical wounds , which may have contributed to the scalp metastasis . certain cases of subcutaneous metastasis of lung cancer may manifest as purple or bright red masses that are ulcerated or cauliflower - like , accompanied by bleeding ( 3,10 ) . the patient in the present case did not experience bleeding , as the mass was discovered early . the scalp accounts for 46.9% of all cutaneous metastases and it is a relatively frequent metastatic site , possibly due to the abundant blood supply and immobility ( 4 ) . skin metastases from internal malignancies tend to occur at a site near the primary tumor ( 11,12 ) through various routes , including lymphatic spread , hematogenous spread and direct implanting . the patient underwent three surgeries for brain metastasis and the mass was located at the surgical site . therefore , the mass was considered to be an implantation metastasis from the previous brain metastases . our patient reported swelling and pain ; therefore , she underwent surgical resection in an attempt to provide local palliation ( 13 ) . during surgery surgical seeding of tumor cells is a known complication of lung cancer surgery ( 14 ) . we considered that subcutaneous spreading of the intracranial tumor may have occurred , rather than metastasis from the lung . the localization of a metastasis along a surgical incision site indicates tumor seeding as the likely mechanism , particularly when a metastasis is apparent on imaging soon after surgery , as in this case . we consider that scalp metastases due to intraoperative seeding may occur in all histopathological grades of lung cancer . the patient in the present case was at high risk for extracranial spreading of intracranial tumors , as she had undergone multiple surgeries . surgical bone defects may compromise the natural barriers to dissemination of intracranial tumors , providing access to the lymphatic system , blood vessels and connective tissues . vascular invasion of the extracranial tissues , migration of neoplastic cells and further growth may potentiate extracranial metastases . however , differentiation between implantation of tumor cells and metastasis from the lung may be difficult . prevention of extracranial spreading of intracranial tumors following resection may be achieved by appropriate closure of the dura mater , changing surgical instruments and gloves for wound closure after the intracranial phase of the surgery , and copious saline irrigation of the wound prior to closure . in our patient , the histology of cutaneous metastasis from lung cancer most commonly reveals adenocarcinoma , followed by squamous / small - cell carcinoma , and large - cell carcinoma ( 8) . immunohistochemistry , particularly ck7ck20 ( 15 ) and ttf-1 is useful for identification of adenocarcinoma . in the present case , ttf-1 , a tissue - specific transcription factor expressed in epithelial cells of the thyroid gland and lung ( 16 ) , confirmed that the primary origin of the adenocarcinoma was the lung . following three surgeries for brain metastases and one surgery for cutaneous metastasis , the patient recovered well and was able to care for herself . the presence of cutaneous metastases in lung cancer is associated with a poor prognosis , as this is an indication that the primary cancer is advanced . the patient in the present case was followed up for > 4 months and continues to show good recovery . the present study was approved by the ethics committee of the first hospital of jilin university . informed patient consent was obtained regarding the publication of the case details and accompanying images .

lung cancer is a common malignancy that is frequently associated with distant subcutaneous metastasis . however , reports of subcutaneous metastasis of lung cancer after three surgeries for recurrent brain metastasis are scarce . the present study describes the case of a 49-year - old female patient who was admitted to our hospital with a cutaneous mass . the patient had a history of lung cancer and had undergone three surgeries for brain metastases . the subcutaneous mass was considered to be an implantation metastasis from the previous brain metastases . the cutaneous mass was grossly resected and histopathological examination revealed adenocarcinoma . this case highlights the need to perform a comprehensive analysis for suspected subcutaneous masses in lung cancer patients . furthermore , pathological examination is crucial for accurate diagnosis and timely treatment .

recent progress in nanotechnology allows to fabricate transistors with a single molecule forming the active region.@xcite the transport properties of such devices have been studied extensively both experimentally and theoretically . theoretical approaches have been reviewed by andergassen _ _ et al.__@xcite and by zimbovskaya and pederson.@xcite the transport properties of single - molecule devices are often dominated by strong interactions . electron - electron interaction , which leads to the coulomb blockade,@xcite and the coupling of electrons to vibrational modes@xcite have to be taken into account . we assume the nuclear motion to be slow on the time scale of electronic transitions , which is the case for most , but not for all , single - molecule devices studied so far.@xcite the electron - vibron coupling is then due to the change of the equilibrium nuclear configuration with the electronic state , i.e. , the franck - condon effect : even if a molecule is initially in a vibrational eigenstate , after an electronic transition it will be in a superposition of vibrational eigenstates belonging to the new electronic configuration . the probability to end up in any one of them is determined by franck - condon matrix elements between vibrational eigenstates for the old and new electronic configurations.@xcite these matrix elements can be very small if the equilibrium value of the relevant normal coordinate changes strongly with the electronic state . consequently , the rates for electrons tunneling into or out of the molecule and thus the current can be strongly suppressed this is the franck - condon blockade.@xcite the dynamics is also unusual in this regime : electrons tunnel in avalanches separated by quiet time intervals.@xcite the avalanche - type transport is self - similar on intermediate timescales and also leads to a strong enhancement of the zero - frequency fano factor.@xcite strong interactions and states far from equilibrium make the description of molecular devices difficult in general.@xcite we here focus on the case of weak hybridization between the molecule and the leads . in this case , master - equation ( me ) approaches@xcite or the equivalent real - time diagrammatic approach@xcite can be employed . in principle , the me takes into account all interactions in the molecule but requires an approximate treatment of the coupling to the leads . the simplest non - trivial version of the me treats the hybridization to second order ( sequential tunneling ) and neglects off - diagonal components of the reduced density matrix in the eigenbasis of the molecular hamiltonian.@xcite the neglect of the off - diagonal components is generally not justified if some of the eigenstates are degenerate , since then the choice of eigenstates in the degenerate subspaces is arbitrary . in the absence of spin - dependent terms in the hamiltonian , spin degeneracy is always present . it is then appropriate to retain all _ secular _ components of the reduced density operator,@xcite i.e. , all diagonal matrix elements and off - diagonal matrix elements between degenerate states . going beyond sequential tunneling , at fourth order one obtains cotunneling and pair tunneling as well as a contribution to the life - time broadening of the molecular levels.@xcite koch _ _ et al.__@xcite include cotunneling but consider only the diagonal components of the reduced density matrix . however , integrating out the off - diagonal terms of second order generates contributions of fourth order to the transition rates between the diagonal components , which are taken into account by leijnse and wegewijs@xcite as well as koller _ _ et al.__@xcite the dynamics of charge transport through molecules , in particular in the franck - condon regime , have so far mostly been studied by considering the current - noise spectrum and the full counting statistics.@xcite for the franck - condon regime , these studies have been augmented by real - time monte carlo simulations.@xcite recently , donarini _ _ et al.__@xcite have considered a harmonically varying bias voltage . assuming spinless electrons and employing the markov and sequential - tunneling approximations , they find hysteretic behavior of current and charge.@xcite in the present paper , we propose and illustrate a different approach to the dynamics : we study the eigenvalue spectrum of the transition - rate matrix appearing in the me . since these eigenvalues describe the decay rates and oscillation frequencies of _ deviations _ of the reduced density matrix from the stationary solution , they provide a complementary view of the dynamics . more specifically , we will consider the part of the spectrum that is small in absolute value , corresponding to states that decay or oscillate slowly . we use the well - studied molecular transistor with a single vibrational mode as a testbed for our idea . the remainder of this paper is organized as follows : in sec . [ sec : theory ] the model is briefly introduced and the me and the relevant approximations are discussed . the transition - rate matrix is introduced and the physical interpretation of its eigenvalues is given . results for the eigenvalue spectra in various regimes are presented and discussed in sec . [ sec : results ] . section [ sec : conc ] summarizes the main results and draws some conclusions . in the following we consider a device containing a single molecule coupled to two electrodes . the device is described by the anderson - holstein hamiltonian @xmath0,@xcite where @xmath1 refers to the noninteracting leads . for simplicitly , we assume that both electrodes have identical band structures and a constant density of states . the operator @xmath2 creates an electron in lead @xmath3 with momentum @xmath4 and spin @xmath5 . the molecule is described by @xmath6 where @xmath7 creates an electron with spin @xmath5 and energy @xmath8 in the molecular orbital , @xmath9 is the corresponding number operator , and @xmath10 is the raising operator of a harmonic vibration mode . in a break - junction device , the on - site energy can be tuned by a gate voltage , which is absorbed into @xmath8 . finally , the tunneling between the molecule and the leads is described by @xmath11 where @xmath12 is the number of sites in one lead , which is often absorbed into @xmath13.@xcite we here assume that the tunneling matrix elements @xmath13 are independent of momentum and spin in the relevant energy range and that the contacts are symmetric . the reduced density operator of the molecule is @xmath14 where @xmath15 is the full density operator of the molecule and the leads and the trace is over all many - particle states of the leads . the full density operator satisfies the von neumann equation @xmath16 . \label{vonneumann}\end{aligned}\ ] ] there are various ways to obtain a me starting from eq.([vonneumann]).@xcite under the condition that the system was in a product states with the leads in ( separate ) thermal equilibrium at some initial time @xmath17 , @xmath18 , one can derive a me that is local in time.@xcite this so - called time - convolutionless me reads @xmath19 - \mathcal{l}(t , t_0)\ , \rho_\mathrm{mol } \equiv \mathcal{a}\ , \rho_\mathrm{mol } \label{tcl.1}\end{aligned}\ ] ] where the commutator induces the bare time evolution of the decoupled molecule and @xmath20 is a linear superoperator describing the coupling to the leads . the right - hand side of the me is linear in @xmath21 so that we can rewrite it as a product involving a superoperator @xmath22 . we write @xmath21 in the basis of eigenstates @xmath23 to the eigenvalues @xmath24 of @xmath25 , where @xmath26 specifies the electronic state and @xmath27 is the quantum number of the vibration . the eigenenergies are @xmath28 where @xmath29 is the number of electrons in the electronic state @xmath30 . the matrix elements of the reduced density operator in this basis are denoted by @xmath31 the me ( [ tcl.1 ] ) written in components reads @xmath32 expressed precisely , our goal is to find the eigenvalue spectrum of the superoperator @xmath22 in the me ( [ tcl.1 ] ) . the physical interpretation of the eigenvalues becomes clear if one inserts the ansatz @xmath33 into eq . ( [ tcl.1 ] ) . here , @xmath34 is a complex number and @xmath35 is an operator on the molecular fock space . this leads to the eigenvalue equation @xmath36 the ansatz ( [ rhoansatz.2 ] ) indeed solves the me if @xmath34 is an eigenvalue of @xmath22 . then , @xmath37 is the negative of the decay rate of the corresponding solution , while @xmath38 is the angular frequency of its oscillations . evidently , a vanishing eigenvalue @xmath39 corresponds to a stationary state . the stationary density operator is thus the right eigenvector @xmath40 if we impose the normalization condition @xmath41 . since the me ( [ tcl.2 ] ) has to preserve the trace of @xmath21 , it must satisfy @xmath42 for all @xmath21 . therefore , @xmath43 with components @xmath44 is a _ left _ eigenvector of @xmath22 to the eigenvalue zero . this proves that at least one stationary state exists . this solution is unique if the system is ergodic in the sense that every state can be reached from every other state by a finite number of transitions.@xcite this condition is satisfied by our model for non - zero temperature . thus there is exactly one eigenvalue @xmath39 . what is the meaning of the other right eigenvectors @xmath35 for @xmath45 ? these eigenvectors are not well - formed density matrices since they have zero trace . this follows from the fact that @xmath43 is a left eigenvector to eigenvalue zero . since the left and right eigenvectors to different eigenvalues are orthogonal , one has for all right eigenvectors @xmath35 to non - vanishing eigenvalues @xmath46 thus one can not interpret @xmath35 as a density matrix . however , linear combinations of the form @xmath47 with constants @xmath48 chosen such that @xmath21 is hermitian , have unit trace and statisfy the me ( [ tcl.1 ] ) . as long as @xmath21 is a positive matrix , it is a permissable time - dependent density matrix . hence , the eigenvectors @xmath35 for @xmath45 describe _ deviations _ of possible density matrices from the stationary state . their time dependence is governed by the eigenvalue @xmath34 . one can show that all eigenvalues @xmath45 have negative real parts,@xcite i.e , they describe deviations from the stationary state that decay for @xmath49 . in practice , approximations are needed to obtain the superoperator @xmath22 . we employ the sequential - tunneling and secular approximations . while these are standard for the study of stationary states , we have to show that they are justified for our purpose of obtaining the eigenvalue spectrum . we assume weak coupling between molecule and leads and expand the right - hand side of eq . ( [ tcl.1 ] ) in powers of @xmath50 . for the tunnel hamiltonian @xmath51 , only even powers of @xmath50 enter . one can thus write @xmath52 here , @xmath53 $ ] is the bare time evolution from eqs . ( [ tcl.1 ] ) and ( [ tcl.2 ] ) . equation ( [ tcl.2 ] ) shows that @xmath54 is diagonal in the basis @xmath55 . we split the reduced density operator into a secular part @xmath56 and a non - secular part @xmath57 and expand both , @xmath58 this expansion allows us to write down the me order by order in @xmath59 . first , we discuss the stationary state , for which the left - hand side of the me ( [ tcl.1 ] ) vanishes . at order zero , we obtain @xmath60 since @xmath54 is diagonal and according to eq . ( [ tcl.2 ] ) gives zero when acting on the secular part @xmath61 , we obtain @xmath62 . this implies that @xmath63 , since @xmath54 multiplies any non - secular component of the reduced density operator by a non - vanishing factor . at second order we thus find @xmath64 the leading secular components are thus of order zero , while the non - secular components are at least of order two . from the me up to second order in @xmath50 , one can not obtain the second - order corrections to the secular part , @xmath65 , this requires to go to fourth order.@xcite the leading - order stationary density operator is thus the solution of @xmath66 with the non - secular components vanishing , @xmath63 . next , we turn to the dynamics . in the me ( [ tcl.2 ] ) , the time derivative of all non - secular components of @xmath21 picks up imaginary factors @xmath67 . they are large compared to the typical scale introduced by the coupling since we assume the coupling to be weak and exclude accidental near - degeneracies . to put it differently , the zero - order superoperator @xmath54 has eigenvalues @xmath68 to eigenstates @xmath69 . these eigenvalues are zero for secular components and large and purely imaginary for non - secular components . as long as the perturbative expansion in @xmath50 is justified , the full superoperator @xmath22 will have eigenvalues close to the zero - order ones , thus some will be small in absolute value , while the rest will have a large imaginary part . we are interested in the part of the spectrum with small absolute value . this is the part lacking large imaginary parts from order zero . consequently , to find the small eigenvalues , one has to consider the secular sector . to leading order , the eigenvalues are then given by the second - order superoperator @xmath70 . consequently , we have to solve the me @xmath71 for the secular density operator @xmath56 . the derivation of @xmath70 is standard and we omit the details.@xcite assuming that at some initial time @xmath17 the molecule and the leads are in a product state with the leads in separate equilibrium , @xmath72 , and taking the limit @xmath73 , one obtains to second order in @xmath50 , @xmath74 } \nonumber \\ & & { } - \frac{1}{\hbar^2 } \int_{0}^{\infty } d\tau\ : \text{tr}_\mathrm{leads}\ , \big[h_t , [ e^{-i(h_\mathrm{leads}+h_\mathrm{mol})\tau/\hbar } \nonumber \\ & & { } \times h_t\ , e^{i(h_\mathrm{leads}+h_\mathrm{mol})\tau/\hbar } , \rho_\mathrm{mol}(t ) \otimes \rho^0_\mathrm{leads } ] \big ] .\quad \label{milo}\end{aligned}\ ] ] we expand the nested commutators and take the trace over the lead degrees of freedom using @xmath75 , \qquad\end{aligned}\ ] ] where @xmath76 , @xmath77 is the chemical potential in lead @xmath78 , and @xmath79 is the fermi function . the chemical potentials in the left and right leads satisfy @xmath80 . we assume that the device is symmetric , i.e. , @xmath81 . in the basis of eigenstates @xmath82 , the me has the form @xmath83 & & { } \label{masterequation}\end{aligned}\ ] ] since we are only interested in the secular sector , we can drop the first term on the right - hand side , which corresponds to @xmath54 . the expressions for the rates @xmath84 also simplify in this sector . the rates appropriate for secular @xmath21 read @xmath85 \nonumber \\ & & { } \times \bigg ( \sum_\sigma d^\sigma_{nn '' } d^{\dagger\sigma}_{n''n ' } f_{qq '' } f^\dagger_{q''q ' } + \sum_\sigma d^{\dagger\sigma}_{nn '' } d^\sigma_{n''n ' } f^\dagger_{qq '' } f_{q''q ' } \bigg ) , \label{r2 } \\ r^{nn'',n'''n'}_{qq'',q'''q ' } & = & \gamma\ , \bigg [ f\bigg(e_{nq}-e_{n''q''}-\frac{ev}{2}\bigg ) + f\bigg(e_{nq}-e_{n''q''}+\frac{ev}{2}\bigg ) \bigg ] \nonumber \\ & & { } \times \bigg ( \sum_\sigma d^\sigma_{nn '' } d^{\dagger\sigma}_{n'''n ' } f_{qq '' } f^\dagger_{q'''q ' } + \sum_\sigma d^{\dagger\sigma}_{nn '' } d^\sigma_{n'''n ' } f^\dagger_{qq '' } f_{q'''q ' } \bigg ) , \label{r4}\end{aligned}\ ] ] where the rate @xmath86 describes the coupling to the electrodes with densities of states @xmath87 , which are assumed to be constant , and @xmath88 , @xmath89 are matrix elements of the electronic operators . the franck - condon matrix elements @xmath90 read explicitly@xcite @xmath91 1 & \mbox{for $ q < q'$ , } \end{array}\right.\end{aligned}\ ] ] and @xmath92 . here , @xmath93 , @xmath94 , and @xmath95 are generalized laguerre polynomials . in eqs . ( [ r2 ] ) and ( [ r4 ] ) , the matrix elements @xmath96 and @xmath97 always appear in combinations corresponding to the creation and annihilation of electrons of the _ same _ spin @xmath5 . this leads to the vanishing of the rates for certain combinations of electronic states . furthermore , the only off - diagonal secular components of @xmath21 are @xmath98 and @xmath99 for all @xmath27 . thus , the rates relevant for the secular sector simplify to @xmath100 \nonumber \\ & & { } \times \bigg ( \sum_\sigma |d^\sigma_{nn''}|^2 |f_{qq''}|^2 + \sum_\sigma |d^\sigma_{n''n}|^2 |f_{q''q}|^2 \bigg ) , \label{r2a } \\ r^{nn'',n'''n'}_{qq'',q''q } & = & \delta_{nn ' } \delta_{n''n'''}\ , \gamma\ , \bigg [ f\bigg(e_{nq}-e_{n''q''}-\frac{ev}{2}\bigg ) + f\bigg(e_{nq}-e_{n''q''}+\frac{ev}{2}\bigg ) \bigg ] \nonumber \\ & & { } \times \bigg ( \sum_\sigma |d^\sigma_{nn''}|^2 |f_{qq''}|^2 + \sum_\sigma |d^\sigma_{n''n}|^2 |f_{q''q}|^2 \bigg ) . \label{r4a}\end{aligned}\ ] ] note that principal - value integrals , which plague the me for the full reduced density operator , cancel in the secular sector . also , the rates in eqs . ( [ r2a ] ) and ( [ r4a ] ) are real . the diagonal components of the me ( [ masterequation ] ) then simplify to @xmath101 while for the off - diagonal secular components we obtain @xmath102 the equations for the diagonal and the off - diagonal components thus decouple and the off - diagonal components exhibit simple exponential decays . averages of local observables such as the electron number in the molecule can be obtained directly from @xmath103 . the current requires a different approach . in the following , we consider a charge current flowing from left to right as positive . the operator @xmath104 for the current between the lead @xmath3 and the molecule is @xmath105 = i\,\frac{\nu e}{\hbar}\ , [ h_t^\nu,\hat n_\nu ] , \label{currentoperator}\end{aligned}\ ] ] where the numerical value of @xmath78 is @xmath106 ( @xmath107 ) for the left ( right ) lead , @xmath108 is the charge of the electron , @xmath109 is the number operator of electrons in lead @xmath78 , and @xmath110 is the part of the tunneling hamiltonian @xmath51 involving lead @xmath78 . the current is then @xmath111 , where @xmath112 is the trace over the full fock space . under the same assumptions as used for the rates above one obtains @xmath113\ , \rho^{nn'}_{qq ' } , \end{aligned}\ ] ] where the sum over @xmath30 , @xmath27 , @xmath114 , @xmath115 only runs over secular components . for the numerical calculations , we cut off the ladder of harmonic - oscillator states so that @xmath116 . then the dimension of the molecular fock space is @xmath117 . the secular part of @xmath21 has @xmath118 components the @xmath117 diagonal ones and @xmath119 off - diagonal ones of the form @xmath98 and @xmath99 . in the secular sector , the density operator can thus be represented by a @xmath118-component vector and the superoperator @xmath70 by a real @xmath120 _ transition - rate matrix_. it is a common problem of the me approach that the matrix @xmath70 can be ill - conditioned , i.e. , the ratio of the largest to the smallest eigenvalue can be very large . this is here due to the fermi functions and franck - condon matrix elements in eqs.([r2a ] ) and ( [ r4a ] ) , which span many orders of magnitude . for this reason , black - box diagonalization routines often fail to distinguish the true stationary state from eigenvectors to very small eigenvalues . to overcome this difficulty , we use mathematica@xcite to solve the eigenvalue problem with high precision . we adapt the number of digits in the calculation such that it is larger than the @xmath121 condition number of the matrix by at least @xmath122 , which should give results for the eigenvalues and eigenvectors with on the order of @xmath122 significant digits . before analyzing eigenvalue spectra in the next section , we comment on their dependence on the cutoff @xmath123 . we find that adding highly excited vibrational states only adds eigenvalues to the middle and upper part of the spectrum . if @xmath123 is not too small , the spectrum at small magnitudes does not change significantly with @xmath123 . this is plausible since adding highly excited vibrational states should not introduce additional slow relaxation channels . we use @xmath124 , unless noted otherwise . it would be possible extend the analysis to higher orders in the tunneling amplitudes @xmath50 . this would require to solve the eigenvalue equation ( [ evaleq.1 ] ) perturbatively . compared to time - independent perturbation theory for _ hamiltonian _ systems , this is more complicated since the superoperator @xmath22 is not hermitian.@xcite in this work , we obtain the eigenvalues @xmath34 up to second order . the next non - vanishing contribution is of fourth order . at this order , the restriction to the secular sector is not possible , we require @xmath70 for all secular and non - secular states , and we also need @xmath125 within the secular sector . the stationary solution at this order has been studied before.@xcite we leave the spectral analysis for a future work . in the present section , we present results for the eigenvalue spectrum in the regimes of the transmitting quantum dot , the coulomb blockade , and the franck - condon blockade . it is shown that the spectrum differs qualitatively between these cases and is characteristic for each . we compare the information that can be gained more conventionally from observables such as current and charge in the stationary state . for relatively small electron - vibron coupling @xmath126 , on - site energy @xmath127 , hubbard interaction @xmath128 , and thermal energy @xmath129 . all energies are given in units of the vibron energy @xmath130.,width=345 ] . the parameters are the same as in fig . [ uli1].,width=326 ] first , we consider the transmitting molecular device . we tune the effective on - site energy @xmath131 in eq . ( [ eigen ] ) to zero so that resonant tunneling is possible at vanishing bias voltage . figure [ uli1 ] shows the current @xmath132 , the electronic occupation number @xmath133 , and the vibron excitation @xmath134 as functions of the bias voltage in the stationary state for relatively small electron - vibron coupling @xmath126 . the current increases with characteristic steps.@xcite there is a step at zero bias since the device is on resonance . the steps at non - zero bias result from inelastic tunneling under excitation of @xmath135 vibron quanta,@xcite in agreement with the observed average excitation @xmath134 . the average electronic occupation changes only weakly and mostly above an energy scale on the order of @xmath136 . this weak dependence is due to a small admixture of doubly occupied states at higher bias voltages . the real and imaginary parts of the eigenvalues @xmath34 of the transition - rate matrix are shown in fig . [ fig1 ] for the same parameters . the eigenvalue zero is always present , as it must be . the real and imaginary parts of the other eigenvalues reflect the step positions from fig . [ uli1 ] , except for the zero - bias step . note that at any voltage , most eigenvalues have vanishing imaginary parts . the eigenvalues with non - vanishing imaginary part form complex - conjugate pairs , since the transition - rate matrix is real . the non - vanishing imaginary parts are typically small compared to the real parts . this means that the decay time of the corresponding deviations from the stationary state is much shorter than their oscillation period . similar behavior is found for randomly distributed transition rates , where it is essentially a consequence of different scaling of the real and imaginary parts with the dimension of the molecular fock space.@xcite at zero bias , all eigenvalues are real . this has to be the case since for @xmath137 the molecule is coupled to an equilibrium bath and all transition rates satisfy detailed balance.@xcite this is easily confirmed by checking that the non - vanishing rates in eq . ( [ me.5a ] ) satisfy @xmath138 at @xmath137 . then for the diagonal components , the transition - rate matrix @xmath22 can be written in the form @xmath139 -\sum_{k\neq i } r^0_{ki}\ , e^{\beta(e_i - e_k)/2 } & \mbox{for $ i = j$ , } \end{array}\right.\end{aligned}\ ] ] where @xmath140 is the inverse temperature and @xmath141 . introducing the diagonal superoperator @xmath142 with components @xmath143 , one easily sees that @xmath144 is real and symmetric and therefore has only real eigenvalues . since this is a similarity transformation , @xmath22 has the same real eigenvalues.@xcite the previous argument only applies to the diagonal components . however , the off - diagonal secular components show a simple exponential decay anyway , as expressed by eq . ( [ me.5b ] ) . concerning our goal of characterizing different regimes in terms of their eigenvalue spectra , the crucial observation is that the spectrum shows a clear gap in the real part . thus there are no slow modes all deviations from the stationary state decay with rates that are on the order of the characteristic rate @xmath145 . it is interesting to analyze the character of the stationary state and of the deviations that decay most slowly . at @xmath137 , the stationary ( equilibrium ) state is a mixture of the microstates @xmath146(b ) and [ uli1](c ) . as discussed , the eigenvectors to non - vanishing eigenvalues represent deviations from the stationary state . the components @xmath147 with the largest magnitudes characterize the microstates that have the largest weight in a given deviation . at @xmath137 , we find that the eigenvalue with the smallest non - vanishing magnitude is actually threefold degenerate it corresponds to three linearly independent deviations . the corresponding subspace is spanned by the hermitian matrices @xmath148 , @xmath149 and @xmath150 . these matrices can be written as @xmath151 where @xmath152 are the pauli matrices and @xmath153 is the projection operator onto the @xmath154 vibron state . the expression ( [ slow.spin ] ) shows that the slowest deviations represent spin polarizations in the @xmath155 , @xmath156 , and @xmath157 direction in the singly occupied sector . evidently , spin polarizations decay most slowly . we will return to this point below . of ( a ) the stationary density matrix and ( b ) the slowest deviation for bias voltage @xmath158 in units of the vibron energy @xmath130 . the other parameters are the same as in figs . [ uli1 ] and [ fig1].,width=345 ] of ( a ) the stationary density matrix and ( b ) the slowest deviation for bias voltage @xmath159 in units of the vibron energy @xmath130 . the other parameters are the same as in figs . [ uli1 ] and [ fig1].,width=345 ] at the first step in fig . [ uli1 ] , where @xmath160 , there is a crossing in the spectrum in fig . [ fig1](a ) and we thus expect the deviation with the smallest decay rate to change in character . figure [ states1 ] shows the secular components of the stationary density matrix and of the slowest deviation at @xmath161 . compared to @xmath137 , the stationary state obtains finite probabilities for low - lying vibron excitions in the sectors of electronic occupation numbers @xmath162 and @xmath163 . the deviation with the smallest decay rate is now non - degenerate and the large components @xmath147 change sign when the occupation changes between @xmath162 and @xmath163 and also when @xmath27 is increased by unity . how can we understand this ? at @xmath161 , @xmath27 can increase at most by unity in a sequential - tunneling event . sequential tunneling also changes the occupation by @xmath164 . the slowest deviation is dominated by an imbalance between the probabilities of the microstates @xmath165 , @xmath166 , @xmath167 , @xmath168 on the one hand and of @xmath169 , @xmath170 , @xmath171 , @xmath172 , @xmath173 on the other . this imbalance relaxes slowly because endothermal transitions between any microstate from one class and any microstate from the other are thermally suppressed . at the third step at @xmath174 , there is another crossing in fig . [ fig1](a ) . figure [ states2 ] shows the secular components of the stationary density matrix and of the slowest deviation at @xmath175 . the stationary state now contains highly excited vibrons . also , the probabilities of doubly occupied states are comparable to those of empty and singly occupied states . the slowest deviation is non - degenerate and mainly involves a transfer of weight between weakly excited vibron states with @xmath176 and highly excited states with @xmath177 . the significance of the number of @xmath178 becomes clear by inspecting the spectra in fig . [ fig1 ] : at @xmath175 , @xmath27 can increase by at most @xmath178 in a sequential - tunneling event , whereas any decrease is possible . the deviation sketched in fig . [ states2](b ) is mainly an imbalance between vibron states that differ in @xmath27 by more than @xmath178 . such a deviation is slow to relax by endothermal sequential tunneling since the relaxation requires more than one transition . we have checked this interpretation by following the slowest deviation to higher voltages . it retains its character but the zero of @xmath179 shifts to higher @xmath27 ( not shown ) . this is expected since for higher voltages larger changes of @xmath27 in a single transition become possible . figure [ fig1](a ) shows that the slowest modes become slower with increasing voltage , due to the decrease of franck - condon matrix elements @xmath180 for larger @xmath181 . for relatively small electron - vibron coupling @xmath126 , on - site energy @xmath182 , hubbard interaction @xmath128 , and thermal energy @xmath129 . all energies are given in units of the vibron energy @xmath130.,width=345 ] . the parameters are the same as in fig . [ uli].,width=326 ] if the molecular energy level @xmath8 is detuned from resonance , there is a non - zero excitation energy between states with different occupation numbers and the current is suppressed at small bias voltages . first , we consider the case that the molecular energy level @xmath8 lies below the fermi energy of the leads at zero bias but the addition energy @xmath183 for a second electron lies above . in this coulomb - blockade regime , the current is suppressed by the coulomb repulsion @xmath136 . for this regime , fig.[uli ] shows the current @xmath132 , the electronic occupation @xmath184 , and the vibron excitation @xmath134 as functions of bias voltage in the stationary state for relatively small electron - vibron coupling @xmath126 . compared to the transmitting regime , we observe coulomb blockade for small bias voltages ( @xmath185 ) , where all three observables are approximately constant and the stationary state is an equal mixture of the degenerate singly occupied ground states @xmath169 and @xmath170 with exponentially small corrections . when the bias voltage reaches a certain threshold , electrons can tunnel out of the molecule so that the average occupation number decreases , see fig . [ uli](b ) , and the current sets in , see fig . [ uli](a ) . for higher voltages , also doubly occupied states occur with significant probability and the average occupation number increases again . similarly to the transmitting regime , the current increases in steps due to inelastic tunneling under excitation of vibrons , as seen from the increase in @xmath134 in fig . [ uli](c ) . figure [ fig3 ] shows the real and imaginary parts of the eigenvalues for the same parameters used in fig . [ uli ] . clearly , as the system enters the coulomb blockade , a non - zero real eigenvalue becomes very small . this is a threefold degenerate eigenvalue corresponding to deviations of the form ( [ slow.spin ] ) . thus in the coulomb blockade , the spin polarization in the singly occupied sector decays very slowly . this is easy to understand : an electron has to tunnel out of the molecule and another electron with opposite spin has to tunnel in ( or vice versa ) to relax the spin . but the first tunneling process is thermally suppressed by the exponentially small tail of the fermi function . if we were to include higher orders in @xmath50 in the calculation , eigenvalues with exponentially small leading - order contribution would generically obtain a contribution of order @xmath186 that is not exponentially suppressed but is still small as long as the pertubative expansion in @xmath50 is justified . we have shown above that the same spin deviations still decay slowly , although not with exponentially suppressed rate , in the transmitting regime . note that the inclusion of the off - diagonal secular components of @xmath21 is necessary to obtain the correct spin symmetry and degeneracy of these slow modes . for relatively small electron - vibron coupling @xmath126 , on - site energy @xmath187 , hubbard interaction @xmath128 , and thermal energy @xmath129 . all energies are given in units of the vibron energy @xmath130.,width=345 ] . the parameters are the same as in fig . [ uli_a].,width=326 ] next , we turn to the two regimes where both @xmath8 and @xmath183 lie either above or below the fermi energy of the leads . then , the molecular orbital in the stationary state is either predominantly empty or doubly occupied , respectively . the two regimes are related to each other by a particle - hole transformation so that the transport properties are very similar . in these regimes it is the single - particle energy rather than the coulomb interaction that suppresses sequential tunneling . we nevertheless continue to use the term `` coulomb blockade '' . for a predominantly empty or doubly occupied molecular orbital , the molecular spin is essentially zero and its relaxation should not be important for the dynamics , like it was in the previous case . we plot the stationary current , electronic occupation , and vibron excitation as functions of the bias voltage for @xmath188 in fig . [ uli_a ] . there is now a broad regime at low bias voltage where the molecular orbital is essentially empty . singly occupied states become available above the coulomb - blockade threshold so that a sequential - tunneling current sets in . vibrons start to be excited at the same point since an electron tunneling out of the molecule has sufficient excess energy to excite the vibration . the corresponding eigenvalue spectra are plotted in fig . [ fig3_a ] . it is striking that in this case no eigenvalue becomes small right at the threshold at @xmath189the gap in the spectrum persists into the coulomb - blockade regime . an eigenvalue approaches zero , i.e. , the gap closes , only at a voltage of @xmath190 . for smaller voltages , even deeper in the coulomb - blockade regime , there are additional transitions where further eigenvalues become small . note that the stationary observables in fig . [ uli_a ] are all exponentially suppressed here . of deviations becoming slow within the coulomb - blockade regime in figs . [ uli_a ] and [ fig3_a ] . panels ( a ) , ( b ) , ( c ) show the modes becoming slow at @xmath191 , @xmath192 , @xmath193 , respectively . the other parameters are the same as in figs . [ uli_a ] and [ fig3_a].,width=345 ] the stationary state is of course dominated by @xmath165 throughout the blockade regime . we now analyze the deviations that become slow as the voltage is lowered . at @xmath194 , a non - degenerate mode becomes slow that mainly involves transfer of weight between @xmath165 and excited vibrational , and to a lesser extend electronic , states . this slow mode is sketched in fig . [ states3](a ) . below the voltage @xmath194 , the excited - state - to - excited - state transitions from @xmath195 to @xmath196 and @xmath197 become suppressed . in particular , the only rapid decay channel of the state @xmath171 ( to @xmath169 and @xmath170 and then to @xmath165 ) is suppressed . therefore , the slowest deviation mostly involves transfer of weight between @xmath171 and @xmath165 . next , at @xmath198 , another non - degenerate mode becomes slow . it is sketched in fig . [ states3](b ) . this mode involves a transfer of weight between the _ two _ lowest vibrational states @xmath165 , @xmath171 on the one hand and mainly the next state @xmath168 on the other . it becomes slow because below this voltage also the decay of @xmath168 is suppressed . analogously , at @xmath199 , a further mode sketched in fig . [ states3](c ) becomes slow due to the suppression of the decay of @xmath200 . if we would increase the on - site energy further by means of a gate voltage , we expect more and more slow modes to appear . for intermediate electron - vibron coupling @xmath201 , on - site energy @xmath202 , hubbard interaction @xmath203 , and thermal energy @xmath129 . all energies are given in units of the vibron energy @xmath130.,width=345 ] . the parameters are the same as in fig . in particular , the electron - vibron coupling is @xmath201.,width=326 ] in this subsection , we turn to the signatures of franck - condon blockade in the spectra . like for the transmitting regime , we tune the effective on - site energy @xmath131 to zero . then resonant tunneling is possible at @xmath137 and any suppression is due to franck - condon blockade . figure [ fig8 ] shows the stationary current , electronic occupation , and vibron excitation as functions of the bias voltage for intermediate electron - vibron coupling @xmath201 . we choose a larger hubbard interaction @xmath204 since for the previously used value of @xmath205 , the effective interaction in eq . ( [ eigen ] ) would become attractive . the main effect of the stronger electron - vibron coupling is the suppression of the zero - bias current step in fig . [ fig8](a ) . the corresponding eigenvalue spectra are plotted in fig . we find a smaller gap at low bias voltage , compared to the case of @xmath126 shown in fig . [ fig1 ] . at @xmath137 , the smallest eigenvalue is threefold degenerate and corresponds to spin imbalances of the form ( [ slow.spin ] ) . the slowest deviations are thus the same as for the transmitting regime , but their decay rate has become even smaller . at first glance , it might be surprising that the enhancement of electron - vibron coupling leads to suppressed _ spin _ relaxation . the reason is that in order for the spin to relax , electrons have to tunnel in and out of the molecule . at low voltage , the only available transitions are between @xmath165 on the one hand and @xmath169 and @xmath170 on the other . but these transitions are now suppressed by the small franck - condon matrix element @xmath206 . the next eigenvalue , which is comparable in magnitude , is not degenerate and corresponds to an imbalance between the empty and singly occupied states . it becomes slow for the same reason . for strong electron - vibron coupling @xmath207 , on - site energy @xmath208 , hubbard interaction @xmath209 , and thermal energy @xmath129 . all energies are given in units of the vibron energy @xmath130.,width=345 ] . inset : absolute value of the smallest non - vanishing eigenvalues on a logarithmic scale . the parameters are the same as in fig . [ fig8_a ] . in particular , the electron - vibron coupling is @xmath207.,width=326 ] finally , we turn to the case of even stronger electron - vibron coupling @xmath210 . the effective on - site energy @xmath131 is again tuned to zero . figure [ fig8_a ] shows the stationary current , electronic occupation , and vibron excitation as functions of the bias voltage for strong electron - vibron coupling @xmath207 and @xmath211 . due to the large value of @xmath136 , a larger cutoff @xmath212 is chosen here . note the current scale in fig.[fig8_a](a ) : the current is strongly reduced in magnitude for all voltages , in particular for small ones , by the franck - condon blockade.@xcite in this regime , the voltage dependence of the occupation number and of the vibron excitation are also suppressed . the corresponding eigenvalue spectra are plotted in fig . [ fig5_a ] . the typical real and imaginary parts have become smaller and the gap is completely filled in at all bias voltages shown here . thus there are slow modes in the whole voltage range . at least at small voltages , the character of the slowest modes is the same as for @xmath201 , though : the most long - lived deviations are spin and charge imbalances , the decay of which is suppressed by small franck - condon matrix elements . the inset in fig . [ fig8_a ] shows details on the small real parts on a logarithmic scale . the small real parts roughly follow a log - uniform distribution for a certain range of rates . within this range , the probability density function is approximately @xmath213 , i.e. , it is scale - invariant . the uniform distribution of @xmath214 is caused by the approximately exponential dependence of the franck - condon matrix elements @xmath180 on @xmath27 and @xmath115 for @xmath215 . the approximate scale - invariance of the distribution of small rates implies that the dynamics of the system within a certain time window is also scale - invariant . this is consistent with the approximate self - similarity of the time - dependent transport found by monte carlo simulations.@xcite in the present paper , we have studied the eigenvalue spectrum of the transition - rate matrix in the me for a molecular quantum dot coupled to metallic leads . the relaxational and oscillatory dynamics of deviations of the system from the stationary state are characterized by the real and imaginary parts of these eigenvalues , respectively . we have mainly considered the small eigenvalues , which describe the slow dynamics . conceptually , this is similar to analyzing the spectrum of low - lying eigenenergies of a _ hamiltonian we have applied this idea to a molecular transistor with an electronic orbital coupled to a vibrational mode . the spectra differ qualitatively between a transmitting device , a molecule in the coulomb - blockade regime , and a molecule in the franck - condon - blockade regime . we demonstrate that the character of deviations from the stationary state can be analyzed by considering the large components of the corresponding eigenvectors . some of the deviations with the smallest decay rates represent non - zero spin polarizations of the molecule . they occur in groups of three degenerate modes corresponding to polarizations in the _ x _ , _ y _ , and _ z _ direction . in order to obtain these modes , all secular components of the reduced density matrix have to be included . in the transmitting regime , the spectrum has a gap for any bias voltage , i.e. , there are no slowly decaying deviations on the scale of the sequential - tunneling rate @xmath145 . in the coulomb - blockade regime with predominantly single occupation of the molecular orbital , the gap in the spectrum closes since relaxation of the electronic spin becomes slow . if instead the molecular orbital is predominantly empty or doubly occupied , there is no finite spin polarization and thus these slow modes do not exist . in these cases , the gap persists into the coulomb - blockade regime . however , deep within these regimes the gap closes and more and more modes become slow at consecutive steps . these modes become slow since excited - state - to - excited - state transitions are thermally suppressed . the dynamics here contains additional information not accessible by observables in the stationary state , which show an exponentially suppressed voltage dependence . for stronger electron - vibron couping we find that the gap becomes small even if resonant tunneling is energetically possible , since certain transition rates are suppressed by small franck - condon matrix elements . in the strong franck - condon - blockade regime , the gap closes over a broad range of bias voltages since many deviations now decay slowly . we also find an approximately scale - invariant distribution of the slowest rates , consistent with the previously observed self - similar dynamics in real time.@xcite in the present paper , we have concentrated on the stationary and long - lived states . the spectra obtained in this paper show additional structure that we have not discussed , suggesting that much more information can be extracted from the spectra and the eigenmodes . m. a. ratner , materials today * 5 * ( 2 ) , 20 ( 2002 ) ; k. s. kwok and j. c. ellenbogen , _ ibid . _ , p. 28 . y. xue and m. a. ratner , in _ nanotechnology : science and computation _ , edited by j. chen , n. jonoska , and g. rozenberg ( springer , berlin , 2006 ) , p. 215 . c. h. ahn , a. bhattacharya , m. di ventra , j. n. eckstein , c. d. frisbie , m. e. gershenson , a. m. goldman , i. h. inoue , j. mannhart , a. j. millis , a. f. morpurgo , d. natelson , and j .- triscone , rev . phys.*78 * , 1185 ( 2006 ) . j. knig , h. schoeller , and g. schn , europhys . lett.*31 * , 31 ( 1995 ) ; j. knig , h. schoeller , and g. schn , phys . lett.*76 * , 1715 ( 1996 ) ; j. knig , j. schmid , h. schoeller , and g. schn , phys . b * 54 * , 16820 ( 1996 ) .

the quantum master equation applied to electronic transport through nanoscopic devices provides information not only on the stationary state but also on the dynamics . the dynamics is characterized by the eigenvalues of the transition - rate matrix , or generator , of the master equation . we propose to use the spectrum of these eigenvalues as a tool for the study of nanoscopic transport . we illustrate this idea by analyzing a molecular quantum dot with an electronic orbital coupled to a vibrational mode , which shows the franck - condon blockade if the coupling is strong . our approach provides complementary information compared to the study of observables in the stationary state .

SECTION 1. AUTHORITY TO CARRY OUT BASE CLOSURE ROUNDS IN 2003 AND 2005. (a) Commission Matters.-- (1) Appointment.--Subsection (c)(1) of section 2902 of the Defense Base Closure and Realignment Act of 1990 (part A of title XXIX of Public Law 101-510; 10 U.S.C. 2687 note) is amended-- (A) in subparagraph (B)-- (i) by striking ``and'' at the end of clause (ii); (ii) by striking the period at the end of clause (iii) and inserting a semicolon; and (iii) by adding at the end the following new clauses (iv) and (v): ``(iv) by no later than January 24, 2003, in the case of members of the Commission whose terms will expire at the end of the first session of the 108th Congress; and ``(v) by no later than March 15, 2005, in the case of members of the Commission whose terms will expire at the end of the first session of the 109th Congress.''; and (B) in subparagraph (C), by striking ``or for 1995 in clause (iii) of such subparagraph'' and inserting ``, for 1995 in clause (iii) of that subparagraph, for 2003 in clause (iv) of that subparagraph, or for 2005 in clause (v) of that subparagraph''. (2) Meetings.--Subsection (e) of that section is amended by striking ``and 1995'' and inserting ``1995, 2003, and 2005''. (3) Staff.--Subsection (i)(6) of that section is amended in the matter preceding subparagraph (A) by striking ``and 1994'' and inserting ``, 1994, and 2004''. (4) Funding.--Subsection (k) of that section is amended by adding at the end the following new paragraph (4): ``(4) If no funds are appropriated to the Commission by the end of the second session of the 107th Congress for the activities of the Commission in 2003 or 2005, the Secretary may transfer to the Commission for purposes of its activities under this part in either of those years such funds as the Commission may require to carry out such activities. The Secretary may transfer funds under the preceding sentence from any funds available to the Secretary. Funds so transferred shall remain available to the Commission for such purposes until expended.''. (5) Termination.--Subsection (l) of that section is amended by striking ``December 31, 1995'' and inserting ``December 31, 2005''. (b) Procedures.-- (1) Force-structure plan.--Subsection (a)(1) of section 2903 of that Act is amended by striking ``and 1996,'' and inserting ``1996, 2004, and 2006,''. (2) Selection criteria.--Subsection (b) of such section 2903 is amended-- (A) in paragraph (1), by inserting ``and by no later than December 31, 2001, for purposes of activities of the Commission under this part in 2003 and 2005,'' after ``December 31, 1990,''; and (B) in paragraph (2)(A)-- (i) in the first sentence, by inserting ``and by no later than February 15, 2002, for purposes of activities of the Commission under this part in 2003 and 2005,'' after ``February 15, 1991,''; and (ii) in the second sentence, by inserting ``, or enacted on or before March 31, 2002, in the case of criteria published and transmitted under the preceding sentence in 2001'' after ``March 15, 1991''. (3) Department of defense recommendations.--Subsection (c)(1) of such section 2903 is amended by striking ``and March 1, 1995,'' and inserting ``March 1, 1995, March 14, 2003, and May 16, 2005,''. (4) Commission review and recommendations.--Subsection (d) of such section 2903 is amended-- (A) in paragraph (2)(A), by inserting ``or by no later than July 7 in the case of recommendations in 2003, or no later than September 8 in the case of recommendations in 2005,'' after ``pursuant to subsection (c),''; (B) in paragraph (4), by inserting ``or after July 7 in the case of recommendations in 2003, or after September 8 in the case of recommendations in 2005,'' after ``under this subsection,''; and (C) in paragraph (5)(B), by inserting ``or by no later than May 1 in the case of such recommendations in 2003, or no later than July 1 in the case of such recommendations in 2005,'' after ``such recommendations,''. (5) Review by president.--Subsection (e) of such section 2903 is amended-- (A) in paragraph (1), by inserting ``or by no later than July 22 in the case of recommendations in 2003, or no later than September 23 in the case of recommendations in 2005,'' after ``under subsection (d),''; (B) in the second sentence of paragraph (3), by inserting ``or by no later than August 18 in the case of 2003, or no later than October 20 in the case of 2005,'' after ``the year concerned,''; and (C) in paragraph (5), by inserting ``or by September 3 in the case of recommendations in 2003, or November 7 in the case of recommendations in 2005,'' after ``under this part,''. (c) Relationship to Other Base Closure Authority.--Section 2909(a) of that Act is amended by striking ``December 31, 1995,'' and inserting ``December 31, 2005,''. SEC. 2. MODIFICATION OF BASE CLOSURE AUTHORITIES UNDER 1990 BASE CLOSURE LAW. (a) Cost Savings and Return on Investment Under Secretary of Defense Selection Criteria.--Subsection (b) of section 2903 of the Defense Base Closure and Realignment Act of 1990 (part A of title XXIX of Public Law 101-510; 10 U.S.C. 2867 note) is amended by adding at the end the following: ``(3) Any selection criteria proposed by the Secretary relating to the cost savings or return on investment from the proposed closure or realignment of a military installation shall be based on the total cost and savings to the Federal Government that would result from the proposed closure or realignment of such military installation.''. (b) Department of Defense Recommendations to Commission.-- Subsection (c) of such section 2903 is amended-- (1) by redesignating paragraphs (4), (5), and (6) as paragraphs (5), (6), and (7), respectively; (2) by inserting after paragraph (3) the following new paragraph (4): ``(4)(A) In making recommendations to the Commission under this subsection in any year after 2000, the Secretary shall consider any notice received from a local government in the vicinity of a military installation that the government would approve of the closure or realignment of the installation. ``(B) Notwithstanding the requirement in subparagraph (A), the Secretary shall make the recommendations referred to in that subparagraph based on the force-structure plan and final criteria otherwise applicable to such recommendations under this section. ``(C) The recommendations made by the Secretary under this subsection in any year after 2000 shall include a statement of the result of the consideration of any notice described in subparagraph (A) that is received with respect to an installation covered by such recommendations. The statement shall set forth the reasons for the result.''; and (3) in paragraph (7), as so redesignated-- (A) in the first sentence, by striking ``paragraph (5)(B)'' and inserting ``paragraph (6)(B)''; and (B) in the second sentence, by striking ``24 hours'' and inserting ``48 hours''. (c) Privatization in Place.--Section 2904(a) of that Act is amended-- (1) by redesignating paragraphs (3) and (4) as paragraphs (4) and (5), respectively; and (2) by inserting after paragraph (2) the following new paragraph (3): ``(3) carry out the privatization in place of a military installation recommended for closure or realignment by the Commission in each such report after 2000 only if privatization in place is a method of closure or realignment of the installation specified in the recommendation of the Commission in such report and is determined to be the most-cost effective method of implementation of the recommendation;''. SEC. 3. TECHNICAL AND CLARIFYING AMENDMENTS. (a) Commencement of Period for Notice of Interest in Property for Homeless.--Section 2905(b)(7)(D)(ii)(I) of the Defense Base Closure and Realignment Act of 1990 (part A of title XXIX of Public Law 101-510; 10 U.S.C. 2867 note) is amended by striking ``that date'' and inserting ``the date of publication of such determination in a newspaper of general circulation in the communities in the vicinity of the installation under subparagraph (B)(i)(IV)''. (b) Other Clarifying Amendments.-- (1) That Act is further amended by inserting ``or realignment'' after ``closure'' each place it appears in the following provisions: (A) Section 2905(b)(3). (B) Section 2905(b)(5). (C) Section 2905(b)(7)(B)(iv). (D) Section 2905(b)(7)(N). (E) Section 2910(10)(B). (2) That Act is further amended by inserting ``or realigned'' after ``closed'' each place it appears in the following provisions: (A) Section 2905(b)(3)(C)(ii). (B) Section 2905(b)(3)(D). (C) Section 2905(b)(3)(E). (D) Section 2905(b)(4)(A). (E) Section 2905(b)(5)(A). (F) Section 2910(9). (G) Section 2910(10). (3) Section 2905(e)(1)(B) of that Act is amended by inserting ``, or realigned or to be realigned,'' after ``closed or to be closed''.

Amends the Defense Base Closure and Realignment Act of 1990 to: (1) provide for continued appointments to the Defense Base Closure and Realignment Commission, authorize the Secretary of Defense to transfer funds for future Commission expenses, and extend Commission authority through December 31, 2005; (2) require the Secretary to include within budget justification documents a force structure plan for the armed forces through FY 2006 (currently, FY 1996); and (3) extend similarly the dates for submission of final selection criteria used for the closure or realignment of military installations, Department of Defense recommendations for such closures or realignments, Commission review and recommendations, and presidential review. Terminates on December 31, 2005 (currently, 1995), the authority to close or realign such installations.Requires base closure or realignment cost saving or return on investment selection criteria to be based on the total cost and savings to the Federal Government.Requires the Secretary, in making closure or realignment recommendations, to consider any notice received from a local government approving such closure or realignment.Allows privatization in place of a military installation recommended for closure or realignment only if privatization is a method specified in the Commission's recommendation and it is determined to be the most cost-effective method of implementation of the recommendation.

In the past three years, 54 of 198 (27.3 percent) NCAA tournament games have been decided by three points or fewer (or went to OT), the most in any three-year span in tourney history. Considering that, along with the unpredictable nature of things all season long in college basketball, we should be in for quite a ride during the next three weeks. So, if you like to consider historical trends -- some more recent than others – when you fill out your bracket, we've got plenty to consider 68, in fact, in honor of the size of the tourney field. You'll have to decide for yourself which ones have merit in this particular tournament. More than anything, though, we hope you find the information below fun to read as you get excited for the start of the Big Dance. (All notes are since the field expanded to 64 in 1985, except where noted) Seed-Specific Notes 1. No. 1 seeds reign supreme No. 1 seeds have won five of the past six championships and 10 of the past 14. In that 14-year span, No. 2 seeds have just one title, while No. 3s have the other three. In fact, only once in the past 24 tournaments has a team seeded worse than third won the championship (fourth-seeded Arizona in 1997). 2. Success rate of No. 1 overall seeds Despite the fact 1-seeds have won the overwhelming majority of titles, it doesn't mean it's going to be the No. 1 overall seed that takes home the trophy. In the nine years that the overall No. 1 seed has been announced by the selection committee, only two have gone on to win the championship (2007 Florida, 2012 Kentucky). How did the other seven fare? Two reached the Final Four, one fell in the Elite Eight and four lost in the Sweet 16 or earlier. Percentage-wise, not a great track record for the supposed favorite to win it all. Louisville hopes to change that. 3. Can Gonzaga do something that's never been done? The Zags are the 10th team to go undefeated in conference play, win their conference tournament and receive a No. 1 seed in the NCAA tournament. None of the previous nine teams to do so won the national title, and there are some big-name squads on the list, too, including Larry Bird and Indiana State in 1979, Houston's Phi Slama Jama in 1983 and the 1991 UNLV team that was unbeaten until falling to Duke in the Final Four. Each of these nine teams did reach the Elite Eight, and four of them fell in the national championship game. Unbeaten in conference and won conference tourney No. 1 seed in NCAA tournament 4. No. 2s have surprisingly few championships In the 28 years since the field expanded to 64 teams, No. 1 seeds have accounted for 17 titles, but No. 2 and No. 3 seeds have just four each. Connecticut was the last 2-seed to win it all in 2004, so even if you go back to 1979, when seeding began, this eight-year championship drought is the longest for the No. 2s. 5. At least one 2-seed won't survive the first weekend You might be surprised to know that only once in the past 16 years have all four No. 2 seeds reached the Sweet 16 (2009). Of course, last year half of the 2-seeds lost their first game, when Missouri fell to Norfolk State and Duke was bounced by Lehigh. 6. No. 3s survive game one, but after that In the past six tournaments, only once has a No. 3 seed lost its round of 64 game (2010 Georgetown was blitzed by Ohio 97-83). However, in the past three tournaments, only five of the 12 3-seeds won their second game to reach the Sweet 16. 7. No. 4s struggle to reach title game Since seeding began in 1979, No. 4 seeds have reached the championship game just twice (winning once), and it happened in consecutive years (1996 Syracuse, 1997 Arizona). 8. Target a No. 4 to lose its first game A No. 4 seed has fallen to a 13-seed in the round of 64 in each of the past five years, the longest streak in the history of the 4/13 matchup. 9. And if you don't pick any 4-seeds to lose their first game History says you should definitely pick one to lose in the round of 32. Since the field expanded to 64 teams in 1985, all four No. 4s have never reached the Sweet 16 in a single tournament. In fact, last year three 4-seeds survived the first weekend for the first time since 2000, and just the fifth time since 1985. 10. Don't get carried away, though Before you go picking too many crazy upsets early on in your bracket, keep in mind that only once have Nos. 13-, 14- and 15-seeds won round of 64 games in the same tourney. That was in 1991, when No. 13 Penn State defeated UCLA, No. 14 Xavier beat Nebraska and No. 15 Richmond knocked off Syracuse. 11. Rarely as easy as 1-2-3-4 Only four times since 1985 have the top four seeds in each region survived the round of 64 (1994, 2000, 2004, 2007). Gordon Hayward's missed half-court shot almost made Butler the first 5-seed to win it all in 2010. AP Photo/Amy Sancetta 12. No. 5s still seeking first championship The No. 5 seed is the highest seed to never win the national title. Butler (2010), Indiana (2002) and Florida (2000) have come the closest, losing in the championship game. No. 6 (1988 Kansas, 1983 NC State) and No. 8 (1985 Villanova) are the only seeds lower than fourth to win it all, but it's been 25 years since it happened last. This year's 5-seeds are Oklahoma State, UNLV, VCU and Wisconsin. 13. This No. 7 has no luck A 7-seed has never reached the championship game, and only one has reached the Final Four (Virginia in 1984). Since the field was expanded in 1985, only seven No. 7s have reached the Elite Eight, including Florida last year. 14. Rarely does the slipper fit for 9-seeds Picking the winner of the 8/9 game is historically a toss-up -- No. 9s actually hold a 58-54 advantage – but asking a 9-seed to win two games has been a greedy request. No. 9 seeds are 4-54 all-time in the round of 32, obviously all against No. 1 seeds. Of the four victors -- Northern Iowa (2010), UAB (2004), Boston College (1994) and UTEP (1992) -- only Boston College was able to reach the Elite Eight. Fun side note: The No. 1 seeds to lose to those No. 9s are the three most successful programs in college basketball history (Kansas twice, Kentucky, North Carolina). 15. Keep an eye on at-large double-digit seeds Since 2000, of the 88 at-large teams seeded 10th or lower to play in the round of 64, 32 came away victorious (36 percent). In the past four tourneys, these teams have a 14-15 record (48 percent) in the round of 64. This year, there are 10 at-large double-digits seeds. Six are from the traditional power conferences (Cincinnati, Colorado, Iowa State, Oklahoma, Minnesota, California), while each at-large team in the First Four (Middle Tennessee, Saint Mary's, Boise State, La Salle) is from a non-"power six" conference. 16. Target a couple of double-digit seeds for your Sweet 16 If you like upsets, the past three years have been fun, as 10 double-digit seeds have reached the Sweet 16 (three in 2010, four in 2011, three in 2012). There has been at least one double-digit seed to survive the first weekend in 26 of the 28 years since the field expanded to 64, and at least two double-digit seeds have done so in 13 of the past 16 years. As mentioned above, it's not just the automatic qualifiers doing the damage here, either. In the past two years alone, five at-large teams seeded 10th or worse advanced to the Sweet 16. That's as many at-large double-digit seeds as did so the previous seven years combined (2004 to 2010). 17. Lowest-seeded Final Four teams The lowest seed to reach the Final Four is a No. 11, done three times (LSU in 1986, George Mason in 2006 and VCU in 2011). They are the only teams seeded lower than eighth to do so. 18. Lower seeds holding their own Not counting the First Four games, 12- and 13-seeds have combined to win 21 games in the past five years (six in 2008, five in 2009, three in 2010, three in 2011, four in 2012). 19. Obligatory note about the danger 12-seeds pose It's one of the first things that comes to mind upon first glance at the bracket: Which 12-seed is going to beat a 5-seed in the round of 64? There's a good reason for that. Excluding the First Four games, 12-seeds have won at least one game in 22 of the past 24 years (no wins in 2000 or 2007), and at least two games in 11 of the past 12 years. 20. If you're looking for a Sweet 16 sleeper, go with a 12-seed Since 1985, in only three years have No. 12 seeds failed to win a round-of-64 game (1988, 2000, 2007). Going a step further, No. 12s have reached the Sweet 16s as many times as 7-seeds (19), more often than 11-seeds (15), more often than 8- and 9-seeds combined (14) and just two fewer times than No. 10s have (21). 21. Stop at one, though! Don't get overzealous, expecting multiple 12s to get to the Sweet 16. Even with the relative success No. 12 seeds have had, only once have two 12s reached the Sweet 16 in the same year (2008). 22. No. 12s not worthy of 'Elite' status No. 12 seeds are 1-18 in Sweet 16 games, with Missouri in 2002 the only one to go any further. That year, the Tigers lost in the Elite Eight to second-seeded Oklahoma. 23. Multiple 13s is ambitious As mentioned earlier, a 13-seed beating a 4-seed is becoming a regular occurrence, but two 13-seeds winning in the same tournament? Not so much. Only three times have two No. 13s won a round of 64 game in the same year (1987, 2001, 2008). 24. Luck bound to run out for No. 13 Last year, Ohio became just the fifth No. 13 seed to reach the Sweet 16, joining Bradley (2006), Oklahoma (1999), Valparaiso (1998) and Richmond (1988). While the Bobcats gave North Carolina all it could handle in that Sweet 16 overtime tilt, we're still looking for our first 13-seed in the Elite Eight. Kyle O'Quinn and Norfolk State pulled off a huge surprise by beating Missouri in a shootout last year. AP Photo/Nati Harnik 25. Can a 15-seed do it again? One-third of the all-time wins by No. 15 seeds came in last year's tournament alone, when Norfolk State edged Missouri and Lehigh beat Duke on the same day. That makes six wins in 28 years for No. 15s, not a strong proposition. One interesting thing from this year's bracket, though, is that a 15-seed in this field (Florida Gulf Coast) actually defeated a No. 2 seed (Miami) earlier this season. 26. So, how many of these monster upsets actually happen? Since 1985, 53 NCAA tournament games have been won by teams seeded 13th, 14th or 15th, an average of fewer than two per year. However, only seven of those 53 came after the round of 64, and never has a team seeded worse than 12th made it to the Elite Eight. 27. Nada-and-112 That's the record of No. 16 seeds against 1-seeds, and most of the time it's not much of a game, either. When UNC Asheville came within seven points of Syracuse in last year's tourney, it became just the 12th 16-seed to keep the margin of defeat in single digits (and the first team to do so since 1997). 28. Difficult for two No. 4s to be "Elite" It has everything to do with having to face mostly top seeds, of course, but only twice since 1985 have two No. 4s reached the Elite Eight in the same tournament (1990 Georgia Tech and Arkansas both reached the Final Four; 1995 Virginia and Oklahoma State -- OSU reached Final Four). Miscellaneous Notes 29. Conference tourneys do matter at least to some degree, that is. No team has won a national title after losing its first game in the conference tournament. The highest-seeded teams in the 2013 field to lose their first conference tourney game are 2-seed Duke and 3-seed Marquette. 30. Parity rules After this wild season when no one team was dominant, Gonzaga is the only team in the field with fewer than four losses. There's never been an NCAA tournament in which every team had four or more losses, but this year marks just the sixth time that only one team in the field had fewer than four losses. In none of the previous five instances did that one team go on to win the title. In fact, only one team (2005 runner-up Illinois) reached the Final Four. Only team with fewer than 4 losses Entering NCAA tournament, all-time 31. Early upsets: How many to pick? Last year marked the third time in the past four tournaments that there were exactly 10 upsets according to seed in the round of 64. Since 1985, there has been an average of 8.1 such upsets. The most in a year is 13 in 2001, and the least is three the year before that. 32. Will a First Four at-large team surprise again? On your bracket, you see "Middle Tennessee/Saint Mary's winner" versus Memphis and "Boise State/La Salle winner" versus Kansas State, but don't be too quick to dismiss the teams on either side of the slashes. In the first two years of the newly-named "First Four," one of the at-large teams to play on Tuesday or Wednesday has also won its round of 64 game. In 2011, 11th-seeded VCU made an improbable run from the First Four to the Final Four, while last year it was 12th-seeded South Florida which defeated Temple in the round of 64. 33. Attention top-ranked teams: Indiana, Michigan, Duke, Louisville, Gonzaga It may surprise you that since the field expanded in 1985, only 44 percent of the national champions (12 of 27) were ranked No. 1 at some point during the season. Since seeding began in 1979, the percentage only gets worse (14-of-34, 41 percent). Last year's Kentucky squad was one of those title teams. 34. Don't dismiss at-large teams with losing conference records While many times they are subject to discussion about whether they belong in the field, history shows they have won their first game more often than not. Beyond that first game, the going gets tougher. Since 1985, 30 teams have received an at-large bid despite having a losing conference record. Of those 30 teams, 16 won at least one game (53 percent). While UConn lost as the only such team last year, the previous two teams to fit the bill (Maryland in 2009, Georgia Tech in 2010) each won a game. And of the 16 teams which won a game, five went on to reach at least the Sweet 16 (just one in the past 11 years, though). There are two teams that qualify in this year's field: Illinois and Minnesota, which both went 8-10 in the Big Ten. 35. Highly-seeded non-power six conference teams have underachieved Since the 1996-97 season, when the Big 8 and Southwest Conferences merged and formed the Big 12, 33 teams from non-power six conferences have gotten a top-four seed. Nearly half of them (16) lost before the first weekend was over. In all, only four reached the Final Four -- 1998 Utah, 2003 Marquette, 2005 Louisville and 2008 Memphis -- with two of them losing in the title game (Utah, Memphis). Of course, Memphis is now the only one of the four still in a non-power six conference. Teams from non-power six conferences to receive top-four seeds in this year's field are Gonzaga, New Mexico and Saint Louis. NOTE: The power six conferences are the ACC, Big 12, Big East, Big Ten, Pac-12 and SEC 36. First-timers unlikely to make noise Heads up, Florida Gulf Coast. Since 1990, of the 78 teams to make their first NCAA tournament appearance, only four have won a round of 64 game. Last year, Norfolk State became the first team to do so in 11 years. There's no question that most of it has to do with the fact many schools who have made their NCAA tournament debuts in the past 23 years have received very poor seeds -- 54 of the 78 were 15- or 16-seeds, and none was seeded better than ninth -- but if you're expecting an upset from a lower seed, it's more likely to come from a team which has been there before. 37. Odds are against a region's top four to survive In this 64-/65-/68-team era, there have been 112 regions played (28 NCAA tournaments). In only 14 of those 112 regions (12.5 percent) have each of the top four seeds advanced to the Sweet 16, none in the past three years. 38. Find a dark horse for an Elite Eight run In 29 of the 34 years of seeding the tournament field, at least one team seeded sixth or worse has reached the Elite Eight. Last year, it was seventh-seeded Florida that kept this surprising trend rolling. 39. Not a top-6 seed? Final Four dreams are rarely realized As fans, we've been spoiled by magical Final Four runs by a pair of 11-seeds (George Mason, VCU) and an 8-seed (Butler) in recent years. Not only is it extremely rare for seeds that low to reach the Final Four, but only 10 teams seeded worse than sixth have reached the Final Four, since seeding began in 1979. It's happened just five times in the past 26 tournaments. 40. Prescient preseason polls? While preseason polls are considered meaningless by many, the fact remains that 12 of the past 15 national champions were ranked in the top nine in the AP preseason poll. Interestingly, the only exceptions are teams which were unranked in the preseason poll (2003 Syracuse, 2006 Florida, 2011 Connecticut). Those three schools are also the only teams in the past 15 NCAA tourneys not seeded No. 1 or 2 to win it all. So, in case you're interested in following this trend in one of your brackets, here are the top 10 teams from October's AP poll: Indiana, Louisville, Kentucky, Ohio State, Michigan, NC State, Kansas, Duke, Syracuse and Florida. Since a team that was unranked in the preseason has won three of the past 10 championships, here's a list of top-4 seeds in the tourney that didn't make the cut in October: Miami, Georgetown, New Mexico, Marquette, Kansas State and Saint Louis. 41. And if you're using preseason expectations to fill out your bracket you might as well hear this, too. Since 2000, all but two Final Fours featured at least two preseason top-10 teams (2006, 2011). 42. Multiple teams from same conference in Final Four no longer a trend One example of a trend that is no more involves multiple teams from the same conference reaching the Final Four. In 17 of the first 22 years after the field was expanded to 64 teams, at least two teams from the same conference reached the Final Four. Nowadays, the wealth is being shared, as four different conferences have been represented in the Final Four in five of the past six years. 43. All No. 1s in the Final Four? Fat chance. Since seeding began in 1979, only once has there been a tournament in which the Final Four was comprised of all No. 1 seeds (2008). What's more likely, of course, is that one or two No. 1 seeds get there; at least one has made it in 27 of 34 years. Conference Notes Kendall Williams and the Lobos give the Mountain West its best chance at a deep run in this year's tourney. AP Photo/Michael Conroy 44. Mountain West teams still searching for success The Mountain West received five bids, its most ever. Last year, the conference got four tourney bids, but earned just one win (5-seed New Mexico). The conference is now only 15-33 overall in 13 years of NCAA tournament play (.313 win percentage) and is still looking for its first Elite Eight appearance. Despite its best teams receiving better seeds in recent years, the Mountain West has failed to turn around its historic struggles. Of the previous 33 Mountain West teams to make the tourney, only 11 won their round of 64 game, and just four advanced to the Sweet 16. But the ugliness doesn't end there. It all comes down to not being able to hang with the big boys. MW teams are 5-28 against power six conference opponents in the tournament (3-17 in the round of 64, 2-7 in the round of 32 and 0-4 in the Sweet 16), and two of those wins came against double-digit seeds. For those who say the conference's lack of success has to do with poor seeding, it is true that only five MW teams have received a top-5 seed before this year. But if you look at those five teams, four won in the round of 64 (all against non-power six opponents, the only loss came against a power six team). And two of the four to win the round of 64 game fell to a power six opponent in the next round. This year, New Mexico and UNLV got top-5 seeds from the Mountain West. 45. For the ACC, this is a drought Each of the past two years, the ACC has not had a team in the Final Four, this after supplying the national champion in 2009 and 2010. It's just the second time since the tournament expanded in 1985 that the ACC did not have a Final Four team in consecutive years. The other was in 2006-07. That makes four times in the past seven years an ACC team failed to make the Final Four. From 1985 to 2005 (21 years), only four Final Fours were played without an ACC team (1985, 1987, 1996, 2003). 46. OVC reverses the curse Despite just one representative, the Ohio Valley Conference has a round-of-64 win in each of the past three years after going 20 straight years without one from 1990 to 2009. This year, OVC newbie Belmont hopes to keep the streak alive, as the Bruins search for their first NCAA tourney win in school history. 47. Ivy issues The Ivy League has failed to win a game in 13 of the past 14 years. Cornell's Sweet 16 run in 2010 is the only exception, although 13-seed Princeton took Kentucky to the wire in 2011 and 12-seed Harvard hung with Vanderbilt last year. Harvard is back again this year, in hopes of earning its first NCAA tournament victory. 48. Return of the MAC? Is the MAC returning to its former pesky status in the bracket? Following the longest NCAA tourney winless drought in conference history (six straight years from 2004 to '09), Ohio has put the MAC back on the list of conferences no higher seed wants to face. The 14th-seeded Bobcats shocked Georgetown with a blowout win in 2010, then were a surprise in the Sweet 16 last year as a 13-seed. This year, Akron tries to win its first NCAA tournament game, although they'll have to do it without suspended starting point guard Alex Abreu. 49. Southland struggles Southland Conference teams have lost 25 of their past 26 round-of-64 games, all but two of which have come by double figures. Northwestern State's stunning comeback versus Iowa in 2006 is the only win in that span. Prior to Northwestern State's win, the last Southland Conference school to win a round-of-64 game was Karl Malone's fifth-seeded Louisiana Tech squad in 1985. Ouch. Mike McConathy and the Demons are back in the Dance for the first time since that 2006 victory in hopes of pulling off another big upset. 50. More of the same for the America East America East teams have lost in the round of 64 each of the past seven years, and 15 of the past 16 years, with all the losses coming by double digits. Vermont's upset of Syracuse in the 2005 round of 64 is the lone win by an America East team since 1996, when Drexel won as member of the league when it was called the North Atlantic Conference. This year's representative, Albany, will have its hands full with a Duke team focused on not falling to a 15-seed for the second straight year. 51. NEC still looking out for No. 1 The Northeast Conference is the only current conference yet to win a round-of-64 game (3-31 overall record, all three wins coming in what would be considered preliminary rounds). That almost changed in 2010, when Robert Morris lost a tight battle to No. 2-seeded Villanova. That's the only time in the past 15 years an NEC team has come within single digits of an NCAA tourney opponent in the Round of 64. LIU Brooklyn will have to escape its First Four matchup with James Madison just for the opportunity to change that. 52. Sad state of affairs in Conference USA Conference USA teams have gone winless in the tourney in each of the past three years, despite sending multiple representatives to the Dance each time. Until this current slump, the conference had never gone winless in a single year since its formation in the 1995-96 season. And after Memphis' four straight seasons as a No. 1 or 2 seed from 2006 to '09, this is the first time in the past four years that a C-USA team received better than an 8-seed (Memphis, which got a 6-seed in the Midwest region, is the conference's only representative). The last time a C-USA team other than Memphis won a tournament game was 2005, when Louisville, Cincinnati and UAB all won games. Team Notes 53. Still looking out for No. 1 Aside from first-timer Florida Gulf Coast, other teams searching for their first NCAA tournament victory are: Akron (0-3), Albany (0-2), Belmont (0-5), Boise State (0-5), Harvard (0-3), Liberty (0-2), LIU Brooklyn (0-5), North Carolina A&T; (0-9) and South Dakota State (0-1). 54. Duke tries to overcome No. 2 jinx This is the fifth time since 1997 that Duke has been a No. 2 seed, but that's not good news like you might expect. The previous four instances resulted in just one Sweet 16 appearance (2009), two round-of-32 exits (1997, 2008) and last year's upset loss to Lehigh in the round of 64. 55. Florida yet to win a close game this season If you were told that Billy Donovan's team has played only six games decided by single digits this season, that might not shock you. But what about if you were told they were 0-6 in those games? That's the case for the Gators, as all 26 of their victories came by double digits and only one of their losses. Considering that they are bound to have to win a close game at some point in this tournament, they will need to rise to the challenge for the first time all season. 56. Hoya Paranoia Georgetown has been eliminated by a double-digit seed and a team seeded at least five spots lower in four straight NCAA tournament appearances, and each of the past three years. And as mentioned above, the Hoyas' first-round opponent is 15-seed Florida Gulf Coast, which has already defeated one No. 2 seed in this year's field (Miami). Georgetown Hoyas Past 4 Appearances 57. Plenty to prove for the Zags Gonzaga is a respectable 9-11 against power six conference opposition in the NCAA tournament, but a deeper look reveals demons this year's team must exorcise. While the Zags are 5-2 against those teams in the round of 64 and 3-4 in the round of 32, consider the following: • Since defeating Florida in the Sweet 16 in 1999, they've lost five straight to power six opponents in the Sweet 16 or later. • The Zags are 2-8 against power six teams seeded fourth or better in any round, and have lost six straight such games since beating St. John's in the round of 32 in 2000 (7-3 against 5-seeds or worse). 58. Self-aware Kansas head coach Bill Self has taken three different schools to the Elite Eight, and has taken the Jayhawks to the Final Four twice (including a championship in 2008). But he's also lost in the round of 64 twice as a top-4 seed at KU, another time in the round of 32 as a No. 1 seed and also lost to 11-seed VCU in the Elite Eight as a No. 1 seed in 2011. Despite all of his success, tournament results have been extremely mixed. 59. Pitino as a No. 1 seed This is the sixth time Rick Pitino has had a No. 1-seeded team in the NCAA tournament (four at Kentucky, two at Louisville). In the previous five instances, his teams have won the championship once (1996), lost in the title game once (1997 to 4-seed Arizona), the Final Four once (1993) and the Elite Eight twice (1995, 2009). The loss to Arizona represents the only time a Pitino-led No. 1 seed wasn't eliminated by a 1- or 2-seed. 60. Can Coach L do it again? Miami is fighting a historical battle in its quest to reach the Final Four for the first time. Not only have the Canes reached the Sweet 16 just once (2000), but they've got just four NCAA tournament wins in their history. Since the field expanded in 1985, only five teams reached their first Final Four in a year in which they entered the Big Dance with fewer than five NCAA tournament wins all-time. The good news for the Hurricanes? The last time it was done was in 2006 by current head coach Jim Larranaga at his former school, George Mason, which did not have a single NCAA tournament win prior to its Final Four run. Reached Final Four Entered with fewer than 5 NCAA tournament wins, Since 1985 61. Being the final unbeaten means little Michigan was the final unbeaten team remaining this season, but that hasn't been a harbinger of NCAA tournament success. Just two times in the past 35 years has the final unbeaten team gone on to win the title (2006 Florida, 1999 Connecticut). 62. Mizzou needs Cinderella run to get off "the list" Missouri has the second most NCAA tournament appearances without reaching a Final Four (25, not counting this year). Only BYU (27) has more. Mizzou also is tied with Boston College for the most NCAA tournament wins (22) without a Final Four appearance. Even if the Tigers get by Colorado State in the second round, they'll have to knock off the No. 1 overall seed Louisville just to get to the Sweet 16. 63. Lost Lobos? Do you like New Mexico to make a run this year? Some experts certainly do, but these particular facts won't support that case. In his first NCAA tournament appearance as a head coach, Steve Alford took 12th-seeded SW Missouri State (now called Missouri State) to the Sweet 16 in 1999, defeating No. 5 Wisconsin and No. 4 Tennessee. However, it's been tough sledding ever since for him, as his teams haven't advanced past the round of 32 in any of his past five trips. His Iowa teams won just one game in three appearances, and lost a round-of-64 game as a No. 3 seed. And despite receiving a top-5 seed in each of his previous two appearances with New Mexico, his Lobos won just one game each time. They'll get another such chance this year, too, and as a 3-seed. Since that 1999 appearance, Alford hasn't defeated a power-six conference opponent (0-3), nor has he defeated a single-digit seed. His three wins have come against 10-, 12- and 14-seeds. 64. Streaking North Carolina has won 10 straight round of 64 games, tied for the second-longest active streak (Purdue has won 14 straight and Maryland 10 straight, but neither is in this year's field). 65. What happened to the luck of the Irish? Since seeding began in 1979, Notre Dame has never won more than two games in a single tournament, and has reached the Sweet 16 just twice since 1985. The Irish have just six wins in eight trips to the Dance under Mike Brey. 66. Buckeyes a top-2 seed again under Matta For the sixth time in their seven NCAA tournament appearances under Thad Matta, Ohio State is a top-2 seed (twice a No. 1, four times as a No. 2). Only twice in those previous five occasions have the Buckeyes advanced past the Sweet 16, though. Last year, as a 2-seed, they fell in the Final Four to Kansas, and in 2007 as a 1-seed they lost to Florida in the national title game. The other three times, they lost in the round of 32 once (2006) and the Sweet 16 twice (2010, 2011). This makes it awfully difficult to know what to expect from the Bucks in this year's tournament. 67. One-and-Dunphy? Temple has just one NCAA tournament victory since legendary head coach John Chaney led the 2001 Owls to the Elite Eight as an 11-seed. Current head coach Fran Dunphy is 2-14 in his career in the NCAA tournament (1-5 at Temple). In two of the past three years, the Owls have lost in the round of 64 as a No. 5 seed. 68. Beating who you should beat Wisconsin has won at least one game in 10 of its past 11 NCAA tournament appearances, but while the Badgers are never fun for opponents to face, they generally have beaten only the teams they should have under Bo Ryan. They are 15-4 against lower-seeded opponents under Ryan, but just 1-7 against higher seeds (that win coming in 2009 versus Florida State). Of those 16 wins, only three have come against teams seeded better than ninth (all three of which were 5-seeds). Special thank you to Jason McCallum and Micah Adams from ESPN Stats & Info for contributing to this column. ||||| Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period. ||||| Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period. ||||| The NCAA Tournament Bracket Is Out. What Will People Be Outraged About This Year? Well, the 68-team NCAA Tournament field has been revealed in full, and you know what that means: it’s 1) time to fill out brackets; and 2) time to get angry about various injustices! First things first, the bracket itself. Here’s a link to it. And even more importantly… Here is a link to a printer-friendly bracket. And now, with that out of the way: controversies! What will people be angry about, now that the field, and the teams who didn’t make the field, are set? Here are a few options: Maybe there actually won’t be that much outrage. This bracket went pretty much according to how most people who study this sort of thing thought it would: First time I can remember that the bubble teams lined up exactly w/ bracketology consensus. No surprises. — Stewart Mandel (@slmandel) March 17, 2013 We know what you’re thinking: consensus? Agreement? Boooooo-ring! Well, don’t worry: there are still some choices plenty will question – and have already questioned. Things like… 1) Miami not getting a 1 seed. The Hurricanes won the ACC’s regular season title, and by virtue of an 87-77 win over North Carolina today, won the conference tournament as well. How wasn’t that enough for a top seed? Well, the Hurricanes aren’t far removed from a stretch where they lost three out of four – and two of those were bad losses, to Wake Forest and Georgia Tech, who each went 6-12 in ACC play. Additionally, they lost to Indiana State and Florida Gulf Coast earlier in the year (FGCU did make the NCAAs, though, albeit as a 15 seed). Plus their main competition for the last No. 1 seed was Gonzaga – and the Zags are, after all, the No. 1 team in the land. A questionable, but understandable move. 2) Not much respect for the Pac-12. Oregon finished second in the Pac-12 during the regular season – one game behind conference winner UCLA. The Ducks followed that up by winning the conference tournament, and finished the season 26-8. They even got a win against UNLV – a 5 seed in the Dance – during non-conference play. Oregon was rewarded for all that with a 12 seed. So was Cal, which tied Oregon’s 12-6 Pac-12 mark. Colorado got a 10 seed. Arizona and UCLA tied for the conference’s best NCAA selection showings, each getting a 6 seed. Maybe the Pac-12 didn’t have its best year, but those are some mid-major-esque seeding numbers. (Good mid-major numbers, though, so there’s that.) 3) Middle Tennessee made the cut, regular Tennessee didn’t. Yeah, the Blue Raiders have to win a play-in first-round game against Saint Mary’s to reach the part of the tournament everyone cares about, but they at least have that chance despite getting only one top-50 win during the year. The Vols, meanwhile, improved greatly in the latter portion of the year, and boasted a win over Florida and a blowout of then-No.-25 Kentucky. However, Middle Tennessee went 19-1 in conference and beat SEC tournament champ Ole Miss in non-conference play. Plenty were happy – or at least not surprised – they made the cut: Thank you committee for putting Middle Tennessee in. — Dana O’Neil (@ESPNDanaOneil) March 17, 2013 Middle Tennessee. Knew it. All about the NC SOS. — Stewart Mandel (@slmandel) March 17, 2013 “Middle Tennessee got in. Good for the Blue Raiders. Good for the NCAA tournament selection committee.” -@eyeoncbb: cbsprt.co/BracketBlog — CBSSports.com (@CBSSports) March 17, 2013 See, we told you there was less controversy than usual. 4) First round rematch. This is something everyone can agree was a less-than-optimal result. The early rounds of the tournament stress novelty, new matchups we didn’t see during the season. So what are UNLV and Cal, who met on Dec. 9, doing in a 5-12 game? Well, according to the selection committee, it was the “best [they] could do.” Well then we DEMAND YOU “DO” BETTER, DAMMIT. 5) Kentucky goes from NCAA champ to a bursting bubble. This one isn’t a controversy so much as a noteworthy development – earlier on the year the Wildcats, while clearly far weaker than last season’s dominant squad, at least looked like they ought to make the 68-team field without a problem. Then… this happened. Nerlens Noel’s torn ACL meant that any NCAA bid was an uphill climb, and it proved too much for them to surmount. They followed up Noel’s injury with a blowout loss to Tennessee, and while a win over Florida last weekend made things interesting, an early SEC Tournament loss to Vanderbilt sealed Kentucky’s fate. Better luck next year, Team Calipari. And… there you have it. Fill out those brackets. Get mad at stuff. Have fun. Feel crushing disappointment. But don’t turn away. March Madness is here in full. Getty photo, by Streeter Lecka ||||| How do you win your NCAA tournament bracket? Just don't think about it. (Photo: Charles LeClaire, USA TODAY Sports) Story Highlights All across the USA, productivity comes to a grinding halt as the work force ponders their NCAA brackets For those of us "experts" who have toiled for decades, knowledge is not always power The tournament went to a seeding system in 1979 If you are reading this, we'll assume that you plan to get no work done in the office this week. Not that there is anything wrong with that. In fact, that just might be the best money-making idea of the year. COMPLETE BRACKET: Printable NCAA bracket BRACKET ANALYSIS: Easiest path to Final Four? All across the USA, productivity comes to a grinding halt as the work force ponders their NCAA brackets. And we've all worked with Bracketheads, those individuals who apply logic, trends and higher math to find the teams that will survive and advance. But what of those who are filling out a bracket for the first time and haven't seen a game this year? Should they go by color or team nickname? Why not? MIDWEST REGIONAL: Analysis and capsules for Louisville's regional WEST REGIONAL: Analysis and capsules for Gonzaga's regional For those of us "experts" who have toiled for decades, knowledge is not always power. Here are some tips for the first timer. Some of them might sound silly, but that doesn't mean you can't win a title with them: Numbers game: Everyone talks about the seeds, and of course the lower the number of the seed the more highly regarded a team is. In the opening round, a No. 1 seed has never lost (112-0) to a No. 16. But that doesn't mean you can always trust the math. Your best bet is picking a No. 9 over a No. 8 (58-54) but there can also be value in the No. 10 vs. a No. 7 (45-67) and the No. 12 vs. a No. 5 (38-74). But remember this, only teams seeded 1, 2, 3, 4, 6 and 8 have won national titles. PHOTOS: FINAL FOUR SLEEPER TEAMS Facebook Twitter Google+ LinkedIn NCAA tournament Final Four sleeper teams Fullscreen Post to Facebook Posted! A link has been posted to your Facebook feed. Like this topic? You may also like these photo galleries: Replay Autoplay Show Thumbnails Show Captions Last SlideNext Slide You're my man blue: If you think it is silly to pick by team colors, then pass on that. But at your own risk. In 2003, the Syracuse Orangeman won the national title. Since then, no team without blue in its colors has won a championship. You might want to zig instead of Zag: Since the coaches began voting in the USA TODAY Sports poll in 1993, the final season No. 1 has won the title just four times. This year's No.1 is Gonzaga. Can I buy a vowel: The tournament went to a seeding system in 1979. In the 34 tournaments played, only four times has the champion team begun with a vowel. Be careful tossing out Indiana though. It won two of those titles. EAST REGIONAL: Analysis and capsules for Indiana's regional SOUTH REGIONAL: Analysis and capsules for Kansas' regional The I's have it: Not all vowels should be avoided. Since 1991, the coach of the national champion has had an "I" in his last name 15 times. Several of those (Mike Krzyzewski, Duke; Roy Williams, North Carolina; Jim Boeheim, Syracuse; Tom Izzo, Michigan State and Rick Pitino, Louisville) have strong teams this year. I didn't catch the name: Since 1991, the winning coach's first name has had either three or four letters. Seed for thought: Give careful consideration to picking too many high seeds in your Final Four. If you add up all the seeds (lowest number would be four if all the No. 1s made it) in the Final Four you don't want to go above 14. That has happened only five times since 1979, when the seeded system was implemented. On caveat: four of the five times it happened, the number was 20 or above. Animal magnetism: Not since 2003 has there been a Final Four without at least one team having an animal as a mascot. In five of those seasons, the national champion's nickname was an animal. PHOTOS: TOP ALL-TIME MARCH MADNESS TEAMS ||||| It’s finally time for the 2013 edition of March Madness to begin, and with the release of the official NCAA college basketball tournament bracket (print yours here), the talk of which unheralded programs will shine is sweeping the nation. Every lower-seeded team will be looking to play the role of Cinderella during the tournament, but several programs are poised to make deep runs despite being underestimated by the selection committee and college basketball fans. All of the following programs have nothing to lose, and that attitude will help carry these teams to great heights in the NCAA tourney. Villanova Brad Penner-USA TODAY Sports The No. 9-seeded Villanova Wildcats (20-13) are being written off in the second round because of the team’s matchup with the No. 8 North Carolina Tar Heels (24-10), but this game is far from a lock. Villanova has a freshman guard named Ryan Arcidiacono that is an absolutely lights-out shooter (averaging 12 points and 3.5 assists), but it wasn’t until he won the starting job that he really developed into a game-changer for the Wildcats. Once Arcidiacono gets hot shooting the ball, there are few teams in the nation that will be able to stop the freshman star. There is no questioning just how talented this Tar Heels team is and how hard it will play on every possession, but Villanova loves to run the floor as well and will stun the South Region by giving North Carolina a second-round upset. Temple USA TODAY Sports The Temple Owls (21-9) are one of the more dangerous all-around teams in the NCAA tournament this year, but a tough second-round matchup against the N.C. State Wolfpack has most college basketball fans picking against the Owls. Unless you want an early loss on your bracket, bracketeers should be taking Temple to stun N.C. State in what is shaping up to be the most interesting No. 8 vs. No. 9 seed matchup of any region. Senior guard Khalif Wyatt is the straw that stirs the Temple drink (averaging 19.8 points, 4.1 assists and 2.9 rebounds per game), and if the Owls can get the starter playing well from the jump, there is no doubt they could make a splash in the East Region. La Salle Howard Smith-USA TODAY Sports Just like the Temple Owls, the La Salle Explorers got no love out of the Atlantic 10 Conference (also finished third in the standings with a 21-9 record), but they are a very dangerous team in the West Region of the bracket. Led by senior guard Ramon Galloway (17 points and 3.8 assists per game), the Explorers have the outside presence to contend with any team in the nation, but the lack of size in the low post will catch up with the team eventually. La Salle plays Boise State in the first round of the tournament on Wednesday for the right to move on to the actual bracket of 64 teams. When the Explorers stop the Broncos, the momentum created could push the team past Kansas State and deep into the bracket. Don't forget to print out your bracket and follow along with the live bracket. Make your picks for the 2013 NCAA tournament here with the Bracket Challenge Game. Follow @Donald_Wood ||||| Photo by Andy Lyons/Getty Images Read more from Slate’s coverage of the NCAA tournament. It's time to get your picks in for the 2014 NCAA Tournament. But what if you don't want to make those picks in the same way you do every year? Last year, Alan Siegel ran through a bunch of alternate ways to run a March Madness pool. The original article is reprinted below. The bracket is out and time is running short—start making your picks already. Tossing in your $5 (or $20 or $50 or a whole lot more) for an NCAA tournament pool is an American tradition. But like many traditions, this one has gotten stale. Most pools work in the exact same way: Everyone fills out a bracket, each correct pick is worth a pre-determined number of points, and whoever ends up with the highest total at the end of the tourney wins. But that’s not the only way to gamble on March Madness. Below, we’ve collected 11 alternate ways to bet on the tournament, ranging from the head-slappingly simple to the absurdly complex. Advertisement (A note about managing your pool online: CBS Sports, ESPN, and Yahoo all have bracket management platforms. Yahoo’s system is the most customizable, which will come in handy if you want to take a non-standard approach to scoring your pool. The website Print Your Brackets also provides templates for some of the variants discussed below.) The Every-Game-Counts Method In the typical pool, the point totals increase incrementally by round: You get one point for each game you pick correctly in the Round of 64, two points for the Round of 32, four for the Sweet 16, eight for the Elite Eight, 16 for the Final Four, and 32 for the championship game. The easiest way to switch things up: Make everything—from the 1-16 matchups in the first round to the title game—worth a single point. Pros: You’ll care about every game. Advertisement Cons: If someone picks a huge amount of early winners, the pool could be locked up before the Final Four. And some lucky yokel could win the whole thing without picking any of the Final Four teams correctly. The Round-Times-Seed Method This is a close relative of the standard bracket challenge, in which the point totals increase as we get deeper into the tournament. In this version, you multiply the points you get for picking a winner by the winning team’s seed. For example, if you correctly predict that Oklahoma, a No. 10 seed, wins in the Round of 32, you get 20 points—the standard two points for a victory multiplied by 10. Cha-ching! Pros: The joy of the NCAA Tournament comes in watching underdogs take down traditional powers. With this system, those big upsets are even more exciting (and more remunerative). Advertisement Cons: As Quora user Ben Greenfield points out, this system “heavily penalizes incorrect underdog picks. Since each successive round is worth twice as much as the previous round, knocking off 1 and 2 and 3 seeds is an extremely dangerous strategy as, after all, they are by far the most likely to actually advance to the valuable late rounds.” Live by the underdog, die by the underdog. The Blind-Draw Method Put the names of every tournament team in a hat (or in one of those spinning lottery drums, if one is available) and have each participant draw one at a time. After everybody has picked once, repeat the process until there are no teams left. Blind-draw pools are scored like traditional pools—each win notched is worth a pre-determined number of points. At the end of the tourney, the spoils go to the person with the most points. Pros: It’s a stress-free selection process. This method frees you from worrying about the potentially disastrous picks you would’ve otherwise spent hours contemplating. Photo by William Mancebo/Getty Images Advertisement Cons: It takes zero thought or skill. The Square Method The tried-and-true Super Bowl method comes to March Madness. Print out a grid, like this one. Fill each of 100 squares with a participant’s name. Here’s how the website Squares Madness explains the next step: After all the squares are taken, “randomly assign numbers 0 through 9 to each column, followed by doing the same for each row. Now each square represents a specific score in the game based on the column and row numbers.” Then, for every game, assign one team to the y-axis and the other to the x-axis. If you match the last digits of the winning and losing team’s final scores, you’re the big winner. Pros: You have 60-plus chances to win. Advertisement Cons: You’re rooting for scores, not teams. (LET’S GO NINE!) The Auction Method Every team is up for grabs, and you can bid on whom you want in your stable. In some variations, each participant has a maximum budget, and you can blow that allotment on a couple of the best teams or diversify with a large group of Cinderellas. In the version that Grinnell College professor Erik Simpson helped come up with, “teams are bought in a standard auction format, with rising bids in 10-cent increments.” Then, each game that one of your teams wins is worth a certain percentage of the total pot. (For example, in Simpson’s pool, each victory in the round of 64 is worth 1.25 percent of the kitty.) Pros: In an email, Daniel Lauve, who developed his own auction format, said: “It’s a good way to personalize the tournament. Each team is tied to exactly one person, and the ‘portfolios’ that people put together usually reflect their personalities. There’s a certain machismo that always results in No. 1 seeds being overbid, and people who don't follow basketball can pick schools they like and participate for a buck or two.” Cons: Organizing a live auction is a pain. Then again, live auctions are really fun. And somebody gets to bang a gavel. The Team Draft Method After drawing for draft order, each member of your group selects a handful of teams, presumably starting with the highly ranked squads, then moving on to the lower seeds. The draft continues until all the teams in the tournament are divvied up. Each participant must have the same number of teams. (If there are leftovers, those teams sit on the sidelines, irrelevant to everyone.) You earn points for each game your teams win. Pros: You get a varied menu of teams to cheer on—a couple of powerhouses, a few mid-tier squads, and a group of sleepers. Cons: Since you’re working with a limited subset of the tournament participants, there will be some games that you don’t care about (at least for gambling purposes). The Compulsive Gambler’s Method This one is based on a World Cup pool described by Geoff Klein on the “Hang Up and Listen” Facebook page. Before each game, everybody in the pool puts a dollar (or any fixed amount) on the team they think is going to win. The winning group then splits the pot. For example, if there are 25 participants and 23 pick Kansas to beat Western Kentucky, a Jayhawks win will net the Kansas backers $1.09 each. (25 divided by 23 equals 1.09.) Pros: What’s better than wagering money on a bajillion college basketball games? Photo by Elsa/Getty Images Cons: Somebody’s got to keep track of a whole lot of bankrolls. The Survivor Pool Method This system, devised by Grantland’s Bill Simmons, works like an NFL suicide pool, where you can only pick each team once. First, you pick two winners for Day 1 (the first Thursday) and two winners for Day 2 (the first Friday). To stay alive, all your teams have to win. If you make it to Day 3 (Saturday) unscathed, you only have to pick a single winner. One loss is fatal, but like in Super Mario Bros., you actually have three lives. During the tourney’s first weekend, you can buy back in up to three times by paying another entry fee. However, every time you buy back in, it gets harder to advance. Buy back after Thursday’s games and you have to pick four winners on Friday; buy back after Friday’s games and you need to pick five winners on Saturday; buy back during Saturday’s games and you need six winners on Day 4 (Sunday). On Sunday, and every day of the tournament thereafter, you need only pick a single winner per day. The last survivor wins the whole pot. Pros: The buy-back process may be a bit fraught and complex, but otherwise this is pretty simple. At most, you’re only picking a handful of games at a time. Cons: You may suffer a quick, painful death. The Fantasy Draft Method As if you’re not in enough fantasy leagues. In this case, forget secondary offensive stats and defense—just draft a bunch of players and tally up how many points they score. “You aren’t necessarily looking for the best player, but rather the guy who is going to play the most number of games and score the most total points,” Evan Pfaff wrote on his website, Big 12 Hoops. He calls this system a “gunner draft.” Whoever gets the best gunners wins. Pros: Risk can be rewarded, handsomely. Imagine if you gambled on Stephen Curry in 2008. During that year’s tournament, the skinny sharpshooter averaged 32 points over four games for No. 10 seed Davidson. Cons: A low-seeded gem like Curry is rare. The most valuable players are the ones on teams likely to go deep in the tournament. That means you’ll be rooting against upsets and picking the starting lineups of Duke, Indiana, and Kansas. D’oh. The Ted Gooley Method In March 2011, the Wall Street Journal’s Carl Bialik profiled biostatistician Ted Gooley, a researcher at Seattle’s Fred Hutchinson Cancer Research Center. In 2007, he unveiled an NCAA pool designed to reward upset picks. “Each correct pick was worth one point divided by the probability that the pick would be correct,” Bialik wrote. “If a team has a 50 percent chance of winning its first game, picking that team would be worth two points. A team with a 20 percent chance would be worth five points—if it won. The goal is to set a fair price for each pick; the favored teams are likely to win but aren't worth many points, while underdogs pay off more if they pull off the upset.” As Bialik explains, Gooley “gathered the results from every tournament since 1985 to see how often teams with a given seed advanced in each round. Then he used the raw numbers to create a statistical model that calculates probabilities even for events that never have happened.” In an email, Gooley told me his system remains sound, although in some cases the point totals have changed. For example, he said, “in 2013, a 15 seed … beating a 2 seed is worth 24.0 points as opposed to in 2011, where this outcome netted you 27.2 points. This is because a 15 seed beating a 2 seed is ‘more likely’ in 2013 than it was in 2011 (and hence worth fewer points), due mainly to the fact that two 15-seeds won games in the first round last year.” (If you’re intrigued by Gooley’s method, check out the Simple Bracket iPhone app, a Kickstarter-funded project that uses the researcher’s NCAA tournament scoring system. At the moment, this is the only way to get the Gooley scoring system.) Pros: Because upsets are worth so much more, it forces timid participants to go out on a limb. “I think mine is the fairest and most equitable way of assigning points,” Gooley told the Journal. Cons: The scoring system may be fair, but it’s quite complex. Good luck keeping track of everyone’s point total. The Bill James Method Bialik’s 2011 exploration of NCAA tournament pool methodology also included a pool developed by stats guru Bill James. The James approach requires each participant to pick one No. 1 seed, one No. 2 seed, one No. 3 seed, and so on down the line. Everyone is allowed to pick whomever they want—there’s no draft or auction. You get points every time one of your teams wins, with victories by underdogs and wins later in the tournament counting extra. Pros: As James told Bialik, “Since it was virtually impossible to have duplicate entries, every ballot was unique, and you could choose whoever you wanted.” And as opposed to draft and auction methods, this system allows for tournament pools of any size. Cons: You don’t get to fill out a bracket. Where’s the fun in that?

– Glance around your office, and odds are you'll see more than one person staring brow-furrowed at a March Madness bracket. Yes, the selection committee released its official bracket yesterday (you can download one here), and that means it's time to identify Cinderellas, pick some 5-12 upsets, and/or randomly guess which university you've maybe heard of will defeat which university you've definitely never heard of. We're here to help. Here's what people around the web are saying about the bracket: High seeds are good: For all the much-buzzed-about upsets, it turns out the selection committee knows a thing or two; No. 1 seeds have won five of the past six championships, ESPN points out, and only once in the past 24 tournaments has a team seeded lower than 4 won it all. But definitely pick some upsets: They'll happen, because this isn't March Rational Outcomes. USA Today suggests picking a 9-seed over an 8-seed, noting that 9-seeds are 58-54 all-time. You could also do worse than picking a 10 over a 7 (45-67) or a 12 over a 5 (38-74). Identify some underrated teams: Bleacher Report suggests Villanova (9), Temple (9), and La Salle (13), all of which the public has largely written off because they're going up against better-hyped foes, but all of which have at least one outstanding star that could put them over the top. Beware Gonzaga: The perennial winner of the "most fun name to say" award has a No. 1 seed this year, after going undefeated in conference play and winning their conference tournament. But be careful; none of the previous nine teams to pull off that feat won the tournament. Try it blind: The Wall Street Journal has a nifty tool letting you pick the teams based on their perceived strengths at various parts of the game—without seeing their names. What to grumble about: Of course, you'll also want to be up on the selection committee outrages. SportsGrid predicts grumbles about Miami's lack of a 1-seed, the lack of respect for the Pac-12, and the omission of Tennessee. Forget brackets entirely: If you think this bracket business is passe, Slate has a list of alternative ways to gamble on the Big Dance.

entangled resources are useful in quantum teleportation , cryptography , and computation . in continuous variable ( cv ) regime , two - mode gaussian entangled states are typically employed as entangled resources . for two - mode gaussian entangled states , entanglement can be fully described by einstein - podolsky - rosen ( epr ) correlation @xcite which is characterized up to the second - order moments of the state @xcite . for two - mode non - gaussian entangled states , however , entanglement is fully described with all orders of moments @xcite . some of us have recently proposed entanglement criteria beyond the gaussian regime , where the entanglement criteria including all orders of epr correlations can be measured with homodyne detection @xcite . non - gaussian entangled states provide the benefits on enhancing violation of bell s inequality @xcite , and degree of entanglement @xcite . a certain class of non - gaussian entangled state is simply generated by applying a non - gaussian operation on a two - mode gaussian state . typical non - gaussian operations are photon addition and subtraction operations . the photon addition operation which was proposed @xcite was implemented @xcite via a nondegenerate parametric amplifier with small coupling strength . the photon subtraction operation was implemented @xcite with a beam splitter of high transmittivity , and considered in enhancing not only entanglement but also performance of quantum - noise - limited amplifier @xcite . the sequential operations , such as photon addition - then - subtraction and subtraction - then - addition operations , were also studied @xcite and implemented in @xcite . in particular , the photon - addition - then - subtraction operation was considered in achieving a noiseless amplifier @xcite , quantifying bosonic behavior in composite particle system @xcite , and distinguishing quantum particles from classical particles @xcite . based on an interferometric setting , the coherent superpositions of second - order operations , @xmath4 , was proposed @xcite and implemented @xcite . moreover , it was also proposed in a cavity system @xcite . some of us have recently proposed the coherent superposition of the elementary operation , @xmath5 @xcite , as well as other coherent superpositions of second - order operations , @xmath6 @xcite and @xmath7 @xcite . other coherent superposition operations , such as @xmath8 and @xmath9 , were also proposed to produce an arbitrary photon - number entangled state in a finite dimension , @xmath10 @xcite . due to the fact that entanglement characteristics of gaussian states are enhanced by a non - gaussian operation @xcite , it is natural to have a question about whether entanglement characteristics of non - gaussian states are enhanced by a non - gaussian operation . in particular , we are interested in non - gaussian states which do not have any two - mode squeezing properties in order to determine their own usefulness compared with a typical gaussian entangled state . then , we apply a simple non - gaussian operation , i.e. , local photon subtraction operation , to the non - gaussian states . we generate the non - gaussian entangled state by injecting a single - mode non - gaussian state and a vacuum state into a 50:50 beam splitter , where we consider a photon - added coherent state @xmath0 and an odd coherent state @xmath1 as the single - mode non - gaussian state . with these non - gaussian entangled states , we investigate the entanglement characteristics : degree of entanglement , second - order einstein - podolsky - rosen ( epr ) correlation , and performance of quantum teleportation in braunstein and kimble ( bk ) s protocol @xcite . after a local photon subtraction operation on the non - gaussian resources in the regime of small @xmath11 , we find that the teleportation fidelity of a coherent state and the second - order epr correlation are enhanced whereas the degree of entanglement diminishes . in the limit of @xmath3 , the counterintuitive effect is more prominent : the teleportation fidelity increases from @xmath12 to beyond the classical limit @xmath13 , and the second - order epr correlation begins to emerge , whereas the degree of entanglement decreases from @xmath14 to @xmath15 . in this paper , we begin in sec . ii with the generation of a non - gaussian entangled state with a 50:50 beam splitter , injecting a single - mode non - gaussian state and a vacuum state . in sec . iii we investigate the entanglement properties ( entanglement and second - order epr correlation ) of the non - gaussian entangled state via local photon subtraction operation . then , we employ the non - gaussian entangled state via local photon subtraction operation for cv teleportation in sec . the main results are summarized in sec . we generate a non - gaussian entangled state by injecting a single - mode non - gaussian state @xmath16 and a vacuum state @xmath17 into a 50:50 beam splitter . we consider a photon - added coherent state @xmath0 , and an odd coherent state @xmath1 as the single - mode non - gaussian state . we can simply check that the single - mode non - gaussian states are maximally nonclassical due to the fact : given @xmath18 for at least one coherent state @xmath19 , then the state is maximally nonclassical @xcite . the photon - added coherent state was implemented in the laboratory @xcite . to generate the odd coherent state was proposed in some ways @xcite , and implemented in other ways @xcite . applying local photon subtraction operations on the non - gaussian entangled state , we can simply obtain the following form , @xmath20 where @xmath21 is a normalization factor , and the beam splitting transformation is @xmath22 . the values of @xmath23 and @xmath24 are non - negative integers . in the case of @xmath25 , the output state @xmath26 becomes @xmath27 . in the case of @xmath28 , the output state @xmath26 becomes @xmath29 $ ] . according to the total number of the photon subtraction operation , the relative phase becomes plus ( minus ) at odd ( even ) number because the state @xmath28 is transformed into an even ( odd ) coherent state by local photon subtraction operations , as shown in eq . ( 2.1 ) . in the next section , we investigate entanglement properties of these non - gaussian entangled states after they are processed with local photon subtraction operation . entanglement for a pure bipartite state is described with von neumann entropy calculated as @xmath30=-tr[\rho_{b}\log_2{\rho_{b } } ] = -\sum_i \lambda_i\log_2{\lambda_i}$ ] , ( @xmath31 : eigenvalues of @xmath32 or @xmath33 ) @xcite . for @xmath25 , the entangled state @xmath34 can be written as @xmath35,\nonumber\\\end{aligned}\ ] ] where @xmath36 , and we considered the relation , @xmath37 . we denote that @xmath38 , and @xmath39 are displaced fock states . the displaced fock states are orthonormal to each other , such that we can get the following reduced density matrix , @xmath40 with the eigenvalues of the eq . ( 3.2 ) , we derive the degree of entanglement as a function of @xmath2 in fig . the degree of entanglement decreases with the total number of the local photon subtraction operation ( @xmath41 ) . in the limit of @xmath42 , the degree of entanglement is changed from @xmath14 to nearly zero via a local photon subtraction operation . for @xmath28 , the entangled state @xmath43 can be written as @xmath44,\nonumber\\\end{aligned}\ ] ] where @xmath45 is an odd coherent state , and @xmath46 is an even coherent state . the odd and even coherent states are orthonormal to each other , such that the reduced density matrix is represented by @xmath47 where @xmath48 $ ] . with the eigenvalues of eq . ( 3.4 ) , the degree of entanglement is derived as a function of @xmath2 in fig . 1 ( b ) . the degree of entanglement decreases from @xmath14 to less than or equal to @xmath14 , via a local photon subtraction operation . in the case of the even number of local photon subtraction operations , the degree of entanglement is constant as @xmath14 . in the case of the odd number , it increases from @xmath15 to @xmath14 with @xmath2 . the above results may be understood by looking into the states in the regime of small @xmath2 . for the state @xmath0 , we consider it up to the first order of @xmath49 , and then the non - gaussian entangled state can be approximately written as @xmath50 where @xmath51 and the state is not normalized . after a local photon subtraction operation on either of the modes , eq . ( 3.5 ) is transformed into @xmath52 in the limit of @xmath53 , eq.(3.5 ) goes to a maximally entangled state but eq.(3.6 ) goes to a separable state . for the state @xmath1 , we consider it up to the third order of @xmath49 , and then the non - gaussian entangled state can be approximately written as @xmath54 where @xmath51 and the state is not normalized . after a local photon subtraction operation on either of the modes , eq . ( 3.7 ) is transformed into @xmath55 in the limit of @xmath53 , eq.(3.7 ) goes to a maximally entangled state but eq . ( 3.8 ) goes to a separable state . second - order epr correlation is described with the total variance of a pair of epr - like operators , @xmath56 where @xmath57 and @xmath58 @xmath59 . the total variance which is less than @xmath14 indicates gaussian quantum entanglement @xcite , an important resource in cv quantum protocols . given a symmetric state , we can evaluate the second - order epr correlation with the expectation values such as @xmath60 , @xmath61 , and @xmath62 . the other terms are obtained with the complex conjugate of the expectation value , e.g. , @xmath63 . in the case of @xmath25 , the second - order epr correlation of eq . ( 2.2 ) is described in this form , @xmath64(1+\cos{2\varphi})}{n_1}\nonumber\\ & & -\frac{|\alpha|^2\cos{2\varphi}}{n_1}-\frac{2|\alpha|^2(n_1+m_1)^2\cos^2{\varphi}}{n^2_1},\end{aligned}\ ] ] where @xmath65 . equation ( 3.10 ) is optimized at @xmath66 . we consider the second - order epr correlation as a function of @xmath2 at @xmath67 , as shown in fig . 2 ( a ) . at @xmath51 , the second - order epr correlation is not shown in the region of @xmath68 . however , applying local photon subtraction operations on the state , we can see that the epr correlation shows up in the region of @xmath69 at @xmath70 . in the region of @xmath71 , the second - order epr correlation is improved by a local photon subtraction operation . in the case of @xmath28 , the second - order epr correlation of eq . ( 2.3 ) is described in this form , @xmath72,\end{aligned}\ ] ] where @xmath65 . equation ( 3.11 ) is optimized at @xmath73 . we consider the second - order epr correlation as a function of @xmath2 at @xmath74 , as shown in fig . 2(b ) . at @xmath75 , the second - order epr correlation is not shown in the whole region of @xmath2 . on the other hand , the second - order epr correlation shows up in the whole region of @xmath2 at @xmath76 . from the above results , we could understand that local photon subtraction operation plays the role of second - order epr correlation for the non - gaussian entangled states . after a local photon subtraction operation on the non - gaussian entangled states , we could see that the second - order epr correlation can be created whereas the degree of entanglement decreases . now we consider the non - gaussian entangled states as entangled resources to teleport a coherent state in continuous variable ( cv ) teleportation . we consider braunstein and kimble ( bk ) s protocol @xcite whose performance is evaluated by the average fidelity between an unknown input state and its teleported state . teleportation of coherent states has a classical limit of average fidelity @xmath77 if alice and bob make use of a classical channel @xcite . the average fidelity of teleportation is given by @xmath78 where @xmath79 @xcite is the characteristic function of the teleported state . here , @xmath80 is the characteristic function of an entangled resource , and @xmath81 is one of an input state . for input coherent states , it is sufficient to calculate the teleportation fidelity for a particular input coherent state @xcite since there is no difference between the amplitudes of the input and output coherent states in bk protocol . for brevity , we will refer to fidelity as the average fidelity hereafter . in the case of @xmath25 , we consider the non - gaussian entangled state eq.(2.2 ) to teleport a coherent state . the characteristic function of the state is given by @xmath82,\end{aligned}\ ] ] where @xmath83 . ( 4.1 ) , we can obtain the teleportation fidelity , which is optimized at @xmath66 for @xmath84 . we consider the teleportation fidelity as a function of @xmath2 at @xmath67 , as shown in fig . 3 ( a ) . at @xmath51 , the teleportation fidelity is less than @xmath85 in the region of @xmath86 . at @xmath70 , the teleportation fidelity becomes larger than @xmath85 in the whole region of @xmath2 . the teleportation fidelity is improved by a local photon subtraction operation in the region of @xmath87 . in the case of @xmath28 , we obtain the following characteristic function , @xmath88 . \nonumber\\\end{aligned}\ ] ] using eq . ( 4.1 ) , we can obtain the teleportation fidelity which is optimized at @xmath73 for @xmath65 . we consider the teleportation fidelity as a function of @xmath2 at @xmath89 , as shown in fig . 3 ( b ) . the teleportation fidelity becomes larger than @xmath85 in the whole region of @xmath2 by an odd number of local photon subtraction operation . we may understand the above result by comparing with the second - order epr correlation and the degree of entanglement . first of all , we compare the teleportation fidelity with the second - order epr correlation in figs . 2 and 3 . in the case of @xmath25 , the teleportation fidelity , which is larger than @xmath85 , does not guarantee the existence of the second - order epr correlation in the region of @xmath90 . in the case of @xmath28 , on the other hand , the teleportation fidelity which is larger than @xmath85 guarantees the existence of the second - order epr correlation . the former case can be explained by all orders of epr correlation , such that we consider another teleportation fidelity formula represented by all orders of epr correlation , @xmath91 @xcite , where @xmath92 [ \hat{b}-\langle\hat{b}\rangle-\hat{a}^{\dag } + \langle\hat{a}^{\dag}\rangle]$ ] . since we consider entangled states generated by a 50:50 beam splitter , the fidelity is simply transformed into @xcite @xmath93 where @xmath94 and @xmath95 . according to eq . ( 2.1 ) , we can derive the expectation value @xmath96 for the input mode b. for the input mode a , we can employ the following relation , @xmath97 thus , in the case of @xmath25 , we can get the following fidelity @xmath98 where @xmath99 and @xmath100 . we can check that the teleportation fidelity @xmath101 is equal to the fidelity obtained from eq . ( therefore , the teleportation fidelity in bk protocol can be explained by all orders of the epr correlation . second , we compare the teleportation fidelity with the degree of entanglement in figs . 1 and 3 . for both cases of @xmath25 and @xmath28 in the regime of small @xmath2 , a local photon subtraction operation enhances the teleportation fidelity whereas the operator diminishes the degree of entanglement . in the limit of @xmath3 , the teleportation fidelity increases from @xmath102 to beyond @xmath85 whereas the degree of entanglement ( @xmath103 ) decreases from @xmath104 to @xmath105 . we can predict that all orders of the correlation in the non - gaussian resources are not always useful to enhance the teleportation fidelity in bk protocol . furthermore , we study some cases about the teleportation fidelity of classical limit @xmath85 regarding entanglement and second - order epr correlation of pure bipartite entangled states , as shown in table i. some entangled states with second - order epr correlation can teleport a coherent state with the fidelity which is beyond @xmath85 @xcite . for the entangled states , @xmath106 and @xmath107 , ( @xmath108 ( @xmath109 ) : two - mode squeezed vacuum state ) , in the region of @xmath110 , however , we can find that the second - order epr correlation can not be exhibited but the teleportation fidelity of a coherent state can be beyond @xmath85 @xcite . there is another example shown in the supplemental material of the paper @xcite , where a single photon state can be teleported with the fidelity up to @xmath14 via an entangled resource with no second - order epr correlation . for the entangled state , @xmath111 , in the region of @xmath112 , there is entanglement as well as second - order epr correlation , but the teleportation fidelity of a coherent state can be below @xmath85 @xcite . for the entangled state at @xmath51 in eq . ( 2.3 ) , there is a high degree of entanglement without second - order epr correlation , but the teleportation fidelity can not be beyond @xmath85 . for any pure bipartite separable states , the teleportation fidelity is below @xmath85 . .teleportation fidelity in bk protocol [ cols="^,^,^,^",options="header " , ] in this paper , we have shown that a local photon subtraction operation on a non - gaussian entangled state , in the regime of small @xmath2 , can enhance the teleportation fidelity and the second - order epr correlation while diminishing the degree of entanglement at the same time . we considered the non - gaussian entangled state generated by injecting a vacuum state and a photon - added coherent state @xmath0 ( an odd coherent state @xmath1 ) into a 50:50 beam splitter . in the limit of @xmath3 , the local photon subtraction operation enhanced the teleportation fidelity by a little bit more than @xmath85 from @xmath102 , and made the second - order epr correlation appear from nonexistence , whereas the degree of entanglement is reduced from @xmath14 to @xmath15 via the local photon subtraction operation . in the regime of large @xmath2 , all the entanglement properties we considered slightly decreased via a local photon subtraction operation . furthermore , we could find the particular cases when the teleportation fidelity can be beyond ( below ) the classical limit @xmath85 without ( with ) second - order epr correlation . the present study can be compared with a gaussian entangled state via a local photon subtraction operation . we consider a two - mode squeezed vacuum state as the gaussian entangled state . we can find the opposite behavior of the gaussian entangled state and the non - gaussian entangled state we considered in this paper . the photon subtraction operation on a two - mode squeezed vacuum state , @xmath111 , enhances the degree of entanglement , but decreases the teleportation fidelity and the second - order epr correlation @xcite . in the small squeezing regime , the teleportation fidelity @xmath113 decreases from @xmath114 to @xmath115 , and the second - order epr correlation goes from existence to nonexistence . according to a quantum protocol , we can apply an appropriate local operation on an entangled state to enhance the performance . in our case , non - gaussian states via a local photon subtraction operation are useful for performing the bk protocol . as a further work , it would be interesting to investigate what kind of local operation on an entangled state is appropriate to enhance the performance of some quantum protocols .

we investigate how the entanglement characteristics of a non - gaussian entangled state are increased or decreased by a local photon subtraction operation . the non - gaussian entangled state is generated by injecting a single - mode non - gaussian state and a vacuum state into a 50:50 beam splitter . we consider a photon - added coherent state @xmath0 and an odd coherent state @xmath1 as a single - mode non - gaussian state . in the regime of small @xmath2 , we show that the performance of quantum teleportation and the second - order einstein - podolsky - rosen - type correlation can both be enhanced , whereas the degree of entanglement decreases , for the output state when a local photon subtraction operation is applied to the non - gaussian entangled state . the counterintuitive effect is more prominent in the limit of @xmath3 .

the interaction of a quantum system with its environment is usually considered to be detrimental for quantum information processing . quantum features one wants to use for quantum information tasks are washed out quickly so that the implementation of quantum gates becomes noisy . in the last decades , however , it has been observed that sometimes noise can be _ beneficial_. rather than fighting against the environment , dissipative state preparation @xcite and dissipative quantum computing @xcite turned out to be valuable alternatives to unitary gate designs . in the context of quantum control theory state preparation and the implementation of unitary gates through the modulation of classical control fields in the presence of a dissipative environment have been studied @xcite and the set of reachable operations has been analyzed @xcite . the environment can be used as a resource to increase the set of operations that can be implemented through the controls @xcite . if the dissipative process admits some set of states robust against the environmental perturbations , the fidelity for the implementation of a gate within the subspaces spanned is not influenced by the noise and the dynamics there is free from decoherence . the existence of the decoherence - free subspaces ( dfs s ) @xcite and the interplay between weak coherent processes and fast relaxation processes make it possible to implement unitary gates over the steady - state manifold in a noiseless manner @xcite . here we show that such a noise process can even raise the fidelity for implementing a desired gate . the action of the strong dissipation allows the implementation of gate operations which can not be realized without the help of the dissipation . the complexity of the dynamics is enhanced by the noise . to show this we build upon the recent results obtained in ref . @xcite . on the basis of the quantum zeno effect @xcite it was shown that frequent projective measurements can enrich the dynamics steered by a set of control hamiltonians . consider two control hamiltonians @xmath0 and @xmath1 which are commutative with each other , @xmath2=0.\ ] ] one is allowed to switch them on and off at will , but can induce only trivial dynamics on the system due to the commutativity . if one additionally performs frequent projective measurements described by a hermitian projection @xmath3 during the control , the system is confined to the subspace specified by the projection @xmath3 due to the quantum zeno effect ( quantum zeno subspace @xcite ) , where the system evolves unitarily ( quantum zeno dynamics @xcite ) according to the projected counterparts of the control hamiltonians , @xmath4 and @xmath5 . these projected hamiltonians do not necessarily commute any more , @xmath6\neq0.\ ] ] the measurement forces the system to evolve within the zeno subspace , in which more complex operations can be realized thanks to the noncommutativity . the same effect can be induced by an infinitely strong dissipative process @xcite . it was shown in ref . @xcite that a strong amplitude damping channel acting only locally on one out of many qubits in a chain typically turns a pair of commuting hamiltonians into a pair of projected hamiltonians that allow us to perform universal quantum computation over the whole chain of qubits apart from the projected one . the amplitude damping acting locally on one qubit out of many , however , is a very special type of noise , and the assumption that it acts only locally seems unrealistic . on the other hand , this effect , _ noise - induced universal quantum computation _ , should arise in more general settings . in this article , we show that the universal controllability over the system can be achieved with the help of more general noise models , including the ones widely studied in the context of dfs s @xcite . dfs s will be identified as the equivalent to the quantum zeno subspaces . even if we are originally able to perform only trivial controls by commuting control hamiltonians , a strong amplitude damping process projects the system onto dfs s , where we achieve universal controllability over the system . we characterize the set of reachable operations within dfs s and provide examples for which universal sets of gates can be implemented . moreover , we perform numerical gate optimization to study how strong the dissipative process needs to be to implement such gates with high precision . as a byproduct a new fidelity function which can be applied in other optimization problems for open quantum systems is developed . dfs s can be exploited as a passive strategy for protecting quantum information against noise @xcite . the theory has been developed in terms of interaction hamiltonians @xcite as well as of quantum dynamical semigroups @xcite . many experiments , such as @xcite , demonstrate the importance of dfs s for noiseless quantum computation . an experimental setup in waveguide qed has also been discussed recently @xcite and we will comment on it in sec . [ sec : numerical gate optimization ] . moreover the combinations with error correcting schemes @xcite and dynamical strategies for decoherence control @xcite are promising possibilities for robust quantum information processing @xcite . a dfs can be seen as a degenerate pointer basis , which is invariant against the dissipative process . consider a purely dissipative dynamics described by the lindbladian generator @xmath7 with @xmath8 the density operator of the system , @xmath9 the lindblad operators acting on the system , and @xmath10 non - negative constants . here we restrict ourselves to a finite - dimensional quantum system with hilbert space @xmath11 of dimension @xmath12 and write @xmath13 for the state space of @xmath11 . a dfs @xmath14 is spanned by @xmath15 characterized by @xmath16 with @xmath17 , @xmath18 complex , and @xmath19 @xcite . clearly if we prepare the system in an initial state @xmath20 , this state is protected from dissipation driven by the dissipator @xmath21 in . we denote by @xmath22 the ( super)projection ( which is not necessarily self - dual ) onto the steady - state manifold which consists of all quantum states @xmath8 satisfying @xmath23 . we assume that the steady states are attractive , i.e. , @xmath24 to which we refer as the long - time / strong - damping limit . in practice , the strong dissipative process quickly destroys the quantum coherence along a given set of directions . having introduced the concept of dfs s we briefly review some results from quantum control theory . consider a quantum system described by a hamiltonian @xmath25 , which suffers from dissipation described by the dissipator @xmath21 in . we try to steer the system by modulating external fields @xmath26 to switch on and off control hamiltonians @xmath27 . the evolution of the system is generated by @xmath28+\mathcal d(\rho),\ ] ] with @xmath29 @xmath30 is a drift hamiltonian , and we do not have access to it . it is known @xcite that in the absence of the dissipator @xmath31 , every unitary operation in the closure of the _ dynamical lie group _ @xmath32 can be implemented with arbitrarily high precision , with @xmath33 being the real lie algebra formed by real linear combinations of the operators @xmath34 and of their iterated commutators . if @xmath35 ( for traceless operators ) , where @xmath36 is the special unitary algebra , the system is said to be fully controllable , that is , every unitary can be implemented up to a global phase . our question is the following . suppose that the lie algebra @xmath37 generated by our hamiltonians @xmath38 is strictly smaller than @xmath36 and only limited unitaries are realizable by our control in the absence of the dissipation @xmath21 . how is the set of reachable operations enlarged by the action of a strong dissipation @xmath31 on the system ? to this end we need to know how the system evolves under the influence of the strong dissipation @xmath21 @xcite . to begin with we consider the situation in which no drift term @xmath30 is present and the dissipator @xmath31 can be switched on and off arbitrarily as well as the control hamiltonians @xmath39 . afterwards we discuss the case in which we have no control over the dissipative part @xmath21 and the drift hamiltonian @xmath25 , assuming that the control fields are all constant . finally this leads to the general case . if we are allowed to control @xmath31 arbitrarily , we can switch rapidly between @xmath22 and a unitary evolution that is generated by @xmath40 $ ] with some @xmath41 and in the limit of infinitely frequent switching @xmath42 it can be shown @xcite that @xmath43,\quad\forall \rho\in s(\mathcal h_{\text{dfs}}^{(i)}),\ ] ] where @xmath44 is the hermitian projection on the @xmath45th dfs . clearly this implies that if we prepare the system in a dfs , say in the @xmath45th dfs , it remains there evolving unitarily with the projected hamiltonian @xmath46 . furthermore if the evolution generated by @xmath31 is unital , i.e. , @xmath47 , the system evolves over the steady state manifold according to @xmath48 $ ] , and for an abelian interaction algebra @xcite , generated by the @xmath9 s in and their conjugates , we have @xmath49 @xcite . the mechanism is similar to that of the quantum zeno subspaces induced by other means , such as frequent measurements , strong continuous couplings , and frequent unitary kicks @xcite . the projective measurement is effectively performed by the dissipative process . the measurement is nonselective @xcite : the transitions among different subspaces are hindered and the dynamics within each subspace is governed by the projected hamiltonian @xmath46 . so far we have discussed the case in which the dissipator @xmath21 as well as the control hamiltonians @xmath39 can be controlled arbitrarily , in the absence of the drift hamiltonian @xmath25 . typically one has no access to the dissipative part @xmath21 in that arises for example from an interaction with the environment . if we assume that the control fields are all constant , the generator including the drift hamiltonian @xmath25 reads @xmath50 where we have introduced the constant @xmath51 that measures the strength of the coherent part @xmath52 $ ] in comparison with the dissipative part @xmath21 . based on a perturbative expansion it has been shown @xcite that @xmath53 where @xmath54 , with @xmath55 the nonvanishing eigenvalues of @xmath31 , defines the longest relaxation time scale @xmath56 . the norm is the usual operator norm and @xmath57 . thanks to this , we notice that on a time scale on which the dissipative dynamics is much faster than the coherent dynamics , the dynamics is effectively governed by . similarly to , if the system is initially prepared in a dfs , say in the @xmath45th dfs , the system evolves unitarily within the same dfs in the limit @xmath58 with @xmath57 , driven by the projected hamiltonian @xmath59 . again , this is intuitively clear : if the dynamics is dominated by the fast dissipative process , the latter defines the subspaces within which the system can evolve . the presence of the coherent component @xmath60 only modifies the motion within each subspace . it is now easy to treat the general case . in the spirit of the trotter formula , by switching among the control hamiltonians under @xmath58 and @xmath57 , we can implement with arbitrarily high precision every @xmath61 in the relevant dfs , with @xmath62 being the real lie algebra generated by the drift hamiltonian @xmath25 and the control hamiltonians @xmath39 projected by the projection @xmath63 . note that for a unital evolution @xmath64 the lie algebra over the dfs s reads @xmath65 the projection @xmath66 can now be identified as the equivalent of the frequent projective measurement that projects the system onto the quantum zeno subspace specified by @xmath63 : the strong dissipation does the same job as the zeno measurement . in the strong - damping limit the system is confined in the dfs s , evolving unitarily and steered by the projected hamiltonians . although the dimensions of the dfs s are smaller than the dimension of the original hilbert space , the dynamics induced by the projected control hamiltonians within the dfs s can be much more complex than the one induced by the original control hamiltonians in the absence of the dissipation , since @xmath67 is in general larger than @xmath68 @xcite . one can even achieve the universal controllability over the dfs s , with the help of the strong dissipation . on the basis of the observation that the projected drift and control hamiltonians do not necessarily commute any more , we saw in the last section that the lie algebra over the dfs s might be larger than the lie algebra over the original hilbert space . in the following we present three different examples , for which the universal controllability over the dfs s is achieved , even though only `` simple '' operations can be implemented over the original hilbert space in the absence of dissipation . we first provide a simplest example with only two qubits , which is essentially the same as that presented in ref . @xcite : one of the two qubits , say qubit 2 , is subject to a strong amplitude - damping process . we also discuss the same model but with a pure dephasing process on qubit 2 , instead of the amplitude - damping process . the drift hamiltonian reads @xmath69 while we have a control hamiltonian @xmath70 where @xmath71 ( @xmath72 ) are the pauli operators . note that these hamiltonians commute with each other , @xmath73=0 $ ] . therefore in the absence of noise the lie algebra @xmath74 is spanned just by @xmath75 and hence is only two dimensional , @xmath76 . we now add amplitude - damping on qubit 2 , generated by @xmath77 with @xmath78 the raising and lowering operators acting nontrivially only on qubit 2 . it projects the system as @xcite @xmath79 where @xmath80 , @xmath81 , and @xmath82 with @xmath83 and @xmath84 being the eigenstates of @xmath85 belonging to the eigenvalues @xmath86 and @xmath87 , respectively . the dissipator ( [ eq : amplitudedamping2 ] ) admits a single dfs identified by the hermitian projection @xmath3 onto @xmath88 in the strong - damping limit our hamiltonians are projected to @xmath89 and the lie algebra over the dfs is given by @xmath90 that is , in the strong - damping limit qubit 1 becomes fully controllable , i.e. , every @xmath91 can be implemented on qubit 1 . now let us replace the amplitude - damping process on qubit 2 by a pure dephasing process generated by @xmath92,\ ] ] where @xmath93 . in this case the system is projected as @xcite @xmath94 where @xmath95 ( @xmath96 ) . this dephasing process admits two orthogonal dfs s identified by the hermitian projections @xmath97 and @xmath98 , [ eq : dfsdephasing ] @xmath99 since the evolution generated by is unital , in the strong - dephasing limit our hamiltonians are projected to @xmath100 and the lie algebra over the dfs s @xmath101 is spanned by @xmath102 : its dimension is @xmath103 and is increased from @xmath76 by the action of the strong pure dephasing on qubit 2 . in particular , if qubit 2 starts from the state @xmath104 ( @xmath105 or @xmath106 ) the lie algebra over the @xmath45th dfs reads @xmath107 and qubit 1 is fully controllable . although in this case we do not have the full controllability over all dfs s , universal quantum computation is possible on qubit 1 within either of the two dfs s . we see that using the framework of dfs s the previous results on amplitude damping channels extend naturally to other types of noise . the next example involves an atom with energy eigenstates @xmath109 plus a higher lying unstable state @xmath110 that decays to the lower lying states with rates @xmath111 , as schematically represented in fig . [ fig : schematicalrepnat ] . we assume that @xmath112 . a similar level structure manifests for example in a rydberg atom , for which the quantum zeno dynamics has recently been demonstrated in an impressive way @xcite . schematic representation of an @xmath113-level atom with a higher lying unstable level @xmath110 that decays with rates @xmath111 to the lower lying levels @xmath109 spanning a dfs . ] we will consider a decay process described by @xmath114 with @xmath115 ( @xmath116 ) . the system is projected as @xcite @xmath117 where @xmath118 , @xmath119 , and @xmath120 . the dissipator ( [ eq : lindbladiannl ] ) admits a dfs identified by the hermitian projection @xmath3 , namely , spanned by the lower lying levels @xmath121 now we are going to introduce a drift hamiltonian and a control hamiltonian . we take an example from ref . @xcite , for which the universal control is achieved through frequent projective measurements described by a hermitian projection @xmath3 . note that here @xmath3 is realized through the strong - damping limit of the completely positive and trace - preserving ( cptp ) map that is generated by the dissipator . the drift hamiltonian @xmath122 consists of the interactions among the lower lying levels @xmath123 and additional driving terms stimulating the transitions between @xmath110 and @xmath124 . the control hamiltonian , on the other hand , reads @xmath125 again , these hamiltonians commute with each other , @xmath73=0 $ ] . therefore in the absence of the noise @xmath21 the lie algebra @xmath74 is spanned just by @xmath75 and hence is only two dimensional , @xmath76 , as in the previous example . these hamiltonians are projected by the strong dissipation ( [ eq : superprojectionnlevel ] ) to @xmath126 this pair of hamiltonians is known to generate the full unitary algebra @xmath127 ( see e.g. @xcite ) . we get @xmath128 its dimension is @xmath129 , while @xmath130 in the absence of the dissipation . compared to the previous two - qubit example we observe here a more dramatic increase of the complexity in the dynamics over the dfs through projection . the third example is a chain of @xmath113 qubits interacting with each other via nearest - neighbor ising - type couplings , [ eqn : ising ] @xmath131 where @xmath132 ( @xmath72 ) are the pauli operators acting on the @xmath133th qubit . we assume that @xmath134 . in addition we are allowed to switch on and off the coupling between the first two qubits , @xmath135 these hamiltonians trivially commute with each other , @xmath136=0 $ ] , and our control over the chain of qubits is very poor . suppose then that this system undergoes a strong collective decoherence described by the lindbladian generator @xmath137 that is unital , where @xmath138 are the collective spin operators . this noise model is well studied in the context of dfs s , and is known to admit multiple dfs s labeled by the total spin @xmath139 of the whole chain [ i.e. , @xmath139 gives the total spin angular momentum of the chain by @xmath140 @xcite . the dimensions of the dfs s are given by @xcite @xmath141 and are listed in table [ tab : djn ] for small numbers of qubits @xmath113 . to see how our hamiltonians @xmath25 and @xmath0 are projected by the collective decoherence @xmath142 in the strong - damping limit , let us look at its dual channel @xmath143 defined by @xmath144 for an arbitrary observable @xmath145 and state @xmath8 , and note that @xmath146 in this case , since @xmath147 in the generator @xmath21 in ( [ eqn : collectivedeco ] ) are hermitian . by this channel , each component of our hamiltonians @xmath148 evolves according to @xmath149 and in the strong - damping limit the operators @xmath150 ( @xmath72 ) are projected to @xmath151 where @xmath152 is a characteristic timescale of the decoherence , e.g. , the smaller nonvanishing eigenvalue of the matrix in ( [ eqn : dstarmatrix ] ) . the operators become rotationally symmetric by the projection . in particular , our hamiltonians @xmath25 and @xmath0 are projected to [ eqn : heisenberg ] @xmath153 the ising chain ( [ eqn : ising ] ) thus becomes the heisenberg chain ( [ eqn : heisenberg ] ) by the projection @xmath154 . the projected hamiltonians are not commutative anymore with each other . now we look at the lie algebra @xmath155 generated by the projected hamiltonians @xmath156 and @xmath157 . recall that the projected hamiltonians in ( [ eqn : heisenberg ] ) are rotationally symmetric , reflecting the character of the decoherence model ( [ eqn : collectivedeco ] ) . commutators preserve this rotational symmetry , as we will see below . then , all the elements of the lie algebra @xmath158 are rotationally symmetric , and are given in terms of the two- and three - body operators ( see appendix [ app : chainlemmaliealg ] for details ) @xmath159 in ref . @xcite , it is proved that any @xmath160 transformations on the dfs s induced by the strong collective decoherence ( [ eqn : collectivedeco ] ) can be realized if we are able to apply swap interactions between any pair of qubits . note that the swap hamiltonians can be constructed from the rotationally symmetric two - body operators @xmath161 : the swap operator @xmath162 swapping the states of qubits @xmath163 and @xmath133 is given by @xmath164 . since we have proven in appendix [ app : chainlemmaliealg ] that all the rotationally symmetric two - body operators @xmath161 can be generated by the projected hamiltonians @xmath156 and @xmath157 , the swap hamiltonians @xmath162 between any pair of qubits can be applied , and by the theorem proved in ref . @xcite all the generators of @xmath165 can be constructed . namely , @xmath166 this means that we are able to perform universal quantum computation over all dfs s by the projected hamiltonians @xmath156 and @xmath157 . .the dimensions @xmath167 of the dfs s , and the dimension of the lie algebra @xmath168 compared with the dimensions of the @xmath169 and @xmath170 algebras over the dfs s , for small numbers of qubits @xmath113 . [ cols=">,^,^,^,^,^,^ " , ] notice , however , that the full unitary algebra @xmath171 over the dfs s is not attainable . for instance , not all the rotationally symmetric four - body operators @xmath172 can be generated . combinations of them can be generated by the rotationally symmetric two- and three - body operators through @xmath173=2(h_{ik}h_{j\ell}-h_{\i\ell}h_{jk}),\ ] ] but we realize that we can generate only differences of four - body operators . the other commutators such as @xmath174 = 4(h_{j\ell}-h_{\i\ell } ) + 2(h_{\i\ell}h_{jk}-h_{ik}h_{j\ell}),\ ] ] do not help to break the differences to get a single piece of four - body operator . this is because commutators yield something antisymmetric with respect to some of the qubits involved in the operators . in order to single out each piece of four - body operator from the differences , we need a sum of four - body operators , but it is not available or provided through commutators . we thus can not generate the full algebra over the dfs s . see table [ tab : djn ] , where the dimension of the lie algebra @xmath175 is compared with the dimension of the @xmath170 algebra @xmath176 and that of the full unitary algebra @xmath177 over the dfs s . the dimension of the lie algebra @xmath175 is indeed larger than @xmath176 , but is smaller than @xmath177 . anyway , the dimension of the lie algebra is greatly enhanced from @xmath76 , as @xmath178 for large @xmath113 , as estimated in appendix [ app : liechain ] . in summary , we started with two commuting hamiltonians @xmath25 and @xmath0 in ( [ eqn : ising ] ) , which are projected to @xmath156 and @xmath157 in ( [ eqn : heisenberg ] ) , respectively , by the strong collective decoherence ( [ eqn : collectivedeco ] ) . as a consequence , the ising chain ( [ eqn : ising ] ) is changed into the heisenberg chain ( [ eqn : heisenberg ] ) , and our projected hamiltonians @xmath156 and @xmath157 are not commutative anymore with each other . they generate the full algebra of @xmath165 on the dfs s . remarkably the noise is turning the ising chain ( classical ) into the heisenberg chain ( quantum ) , and we are able to perform a universal quantum computation over the dfs s . in this section we analyze how the process fidelity scales with the noise strength . to this end we resort to the numerical gate optimization using the quantum control package implemented in qutip @xcite . we study the two - qubit example discussed in sec . [ examplestwoq ] , with the amplitude damping for different values of @xmath179 . for the sake of simplicity the drift hamiltonian is treated as a control hamiltonian as well . we wish to optimize the control fields @xmath180 [ recall ( [ eqn : ht ] ) ] to implement some goal operation @xmath181 . denote by @xmath182 $ ] the cptp map at time @xmath183 , where @xmath184 is the liouvillian given in ( [ eq : totalgenerator ] ) and @xmath185 indicates time - ordered product . the optimization is performed to minimize the gate error @xmath186 where @xmath187 is the hilbert - schmidt norm with @xmath181 and @xmath188 being treated as @xmath189 matrices obtained by the row - vectorization of the density operator of a @xmath12-dimensional system . in general , for two cptp maps @xmath190 and @xmath191 , the hilbert - schmidt norm of the difference between their corresponding matrices provides an upper bound @xmath192 on the diamond norm @xmath193 . the diamond norm @xcite takes its maximal value @xmath194 when the two quantum channels @xmath190 and @xmath191 are perfectly distinguishable . the minimization of is done by a gradient - based algorithm @xcite dividing the total time @xmath183 into equidistant time intervals , on which the control fields are piecewise constant . we are actually interested in the reduced dynamics of system 1 , i.e. , in the map @xmath195 with @xmath196 and @xmath197 the initial states of systems 1 and 2 , respectively , and @xmath198 the partial trace over system 2 . we wish to optimize @xmath188 such that @xmath199 becomes some goal unitary map @xmath200 with @xmath201 and @xmath202 . our measure of error @xmath203 in ( [ eq : gateerror ] ) , however , depends also on how the channels @xmath204 and @xmath205 act on system 2 : even if @xmath206 coincides with the goal unitary @xmath200 , the total maps @xmath204 and @xmath205 can be different and our measure of error @xmath203 can be nonvanishing . in addition , the reduced map @xmath206 depends on the initial state of system 2 . we notice , on the other hand , that since the goal operation on system 1 is unitary @xmath207 the total goal operation must factorize @xmath208 with @xmath209 an arbitrary cptp map acting on system 2 . what is more relevant is how close the reduced channel @xmath206 is to the goal unitary @xmath207 . therefore it would be more appropriate to perform an additional minimization of @xmath203 in ( [ eq : gateerror ] ) over @xmath209 . to obtain the subsystem fidelity for purely unitary channels this minimization can be carried out analytically @xcite but unfortunately for arbitrary cptp channels this is a challenging task . instead we use the normalized choi representation @xmath210 of a quantum channel @xmath211 @xcite to derive a lower bound of @xmath203 , @xmath212 where the swap operator @xmath213 between systems 1 and 2 is introduced because in general for two cptp maps @xmath190 and @xmath191 , @xmath214 . for details of the derivation of the lower bound we refer to appendix [ lowerbound ] . clearly the minimization over @xmath209 on the left - hand side of is now lower bounded by @xmath215 , which is independent of @xmath209 and is zero if and only if the goal unitary operation on system 1 is reached . thus the lower bound becomes tighter and tighter when @xmath188 factorizes into the goal unitary @xmath207 on system 1 and some arbitrary @xmath209 on system 2 . ( colour online ) numerical gate optimization for the two - qubit model in sec . [ examplestwoq ] with the amplitude damping for different values of @xmath179 . the gate error between the reduced dynamics @xmath199 and the hadamard gate on qubit 1 obtained from the numerical minimizations of @xmath216 ( green triangles ) and @xmath215 ( blue points ) for different values of @xmath179 with gate time @xmath217 . qubit 2 is initially prepared in the totally mixed state , and for @xmath216 , @xmath209 is chosen to be the superprojection @xmath154 that brings qubit 2 into the ground state @xmath83 . to reduce the effect of local minima in the minimum value 100 randomly chosen initial pulses are taken . ] the strategy to study the convergence of the map to the goal operation as @xmath179 is increased can now be summarized as follows . we implement @xmath215 and its gradient with respect to the control fields on qutip , and minimize @xmath216 and @xmath215 for different values of @xmath179 . for @xmath216 , @xmath209 is chosen to be the superprojection @xmath154 in ( [ eqn : ptwoqubitamp ] ) that brings qubit 2 into the ground state @xmath83 . on the basis of the minimizations of @xmath216 and @xmath215 we evaluated in fig . [ fig : fid ] the gate error @xmath218 by specifying the initial state of qubit 2 in the totally mixed state and tracing out the auxiliary degrees of freedom . the target unitary operation @xmath219 on qubit 1 was chosen to be the hadamard gate . we observe that despite the enhanced freedom in @xmath215 the curves based on the minimizations of @xmath203 and @xmath220 are similar to each other . for noise strengths above @xmath221 gate errors below @xmath222 can be reached , corresponding to the upper bound @xmath223 for the diamond norm . it demonstrates that with intermediate noise strengths reasonable fidelity can be reached . besides being fundamentally interesting we now want to discuss in more detail the experimental feasibility of this observation . together with controlling commuting interactions , the main ingredient of the observed behavior is a strong dissipative process and the emergence of dfs s . thus , in practice , we need a system containing a subset of states that are stable on an appropriate time scale and a dissipative process decaying into this subset , while being much faster than other noise processes . an attractive platform that provides such a noise process is waveguide qed , i.e. , the interaction of quantum emitters with the modes of a waveguide , such as photonic crystal waveguides @xcite , optical fibers @xcite , and superconducting circuits @xcite . for further details regarding waveguide qed we refer to @xcite and references therein . in particular , in such systems the presence of collective decoherence described by a lindbladian of the form gives rise to dfs s and moreover the high density of modes of the waveguide yields regions in which large decay rates are achieved . recently , the ability to implement universal gates in such systems over a dfs was studied in detail in @xcite . while in this study weak driving fields with a constant envelope were used to implement a target unitary gate , we remark that there is no fundamental restriction of using time - dependent controls to implement the ideas that are proposed here similarly . indeed , it was shown that as long as the distance between the quantum emitters in the waveguide is small , the gate error @xmath224 for implementing a specific gate over the dfs scales as @xmath225 @xcite . here @xmath226 is the purcell factor given by the ratio of the decay rate @xmath179 into the dfs and the decay rate @xmath227 of other noise channels , such that a unitary gate can accurately be implemented if the purcell factor is reasonably large . together with the ability to individually address transitions of the embedded quantum emitters waveguide qed systems provide therefore a promising platform for noise - induced universal quantum computation . we showed that every dissipative process exhibiting a dfs can enlarge the set of unitary operations that can be implemented by means of classical control fields . we provided three examples for which a universal set of gates can be implemented over a dfs whereas over the original hilbert space only `` simple '' operations are possible . in particular we showed that a realistic noise model can map a commutative classical system into a universal quantum one . numerical gate optimization was performed to study how strong the dissipative process needs to be to implement some unitary gate over the dfs with high precision . as a result a subsystem fidelity for open quantum systems was developed . our results pave the way to experimental feasibility studies in noisy systems such as quantum emitters in a waveguide . we thank thomas - schulte herbrggen for fruitful discussions , hpc wales for providing a high performance computer cluster on which the numerical simulations were done , and alexander james pitchford for advice regarding the numerical simulations and developing qutip . ca acknowledges financial support from a hpc wales bursary and the aberystwyth doctoral career development scholarship . db acknowledges support from the epsrc grant ep / m01634x/1 . ky is supported by the grant - in - aid for scientific research ( c ) ( no . 26400406 ) from the japan society for the promotion of science ( jsps ) and by the waseda university grants for special research projects ( no . 2015k-202 and no . 2016k-215 ) . this work was also supported by the top global university project from the ministry of education , culture , sports , science and technology ( mext ) , japan , by the italian national group of mathematical physics ( gnfm - indam ) , by infn through the project `` quantum , '' and by prin grant no . 2010llkjbx `` collective quantum phenomena : from strongly correlated systems to quantum simulators . '' we prove the following lemma : the lie algebra @xmath158 generated by the two projected hamiltonians @xmath156 and @xmath157 in ( [ eqn : heisenberg ] ) includes all the rotationally symmetric two- and three - body operators , @xmath161 and @xmath229 ( @xmath230 ; @xmath231 ; @xmath232 ) defined in ( [ eqn : twothreebody ] ) , for any number of qubits @xmath134 . let us introduce @xmath233 the first commutator reads @xmath234 = 2h_{123}.\ ] ] then , by commuting @xmath235 with the newly generated @xmath236 twice , we have @xmath237 & = 4(h_{13}-h_{23 } ) , \\ \i\bm{[}\i[h_{12},h_{123}],h_{123}\bm { ] } & = 16(h_{13}+h_{23}-2h_{12}),\end{aligned}\ ] ] from which we gain @xmath238 and @xmath239 . all the rotationally symmetric operators up to the third qubit ( three two - body operators @xmath240 , @xmath239 , @xmath238 and a three - body operator @xmath236 ) are in our hands . for @xmath241 , we proceed by induction . suppose that all the rotationally symmetric two- and three - body operators for the first @xmath133 qubits are at our disposal . it is actually the case for @xmath242 , as we saw above . then , we are able to extend one qubit further , generating all the two- and three - body operators involving the @xmath243th qubit by the following procedure . \1 . commute @xmath244 with @xmath245 to extend to the @xmath243th qubit , @xmath246 = -2 ( h_{(n-2)(n-1)n } - h_{(n-1)n(n+1 ) } ) .\ ] ] we acquire @xmath247 . \2 . by commuting @xmath244 with the newly generated @xmath247 twice , we have @xmath248 = 4(h_{(n-1)(n+1)}-h_{n(n+1)}),\\ & \i\bm{[}\i [ h_{(n-1)n},h_{(n-1)n(n+1)}],h_{(n-1)n(n+1)}\bm { ] } \nonumber\\ & \qquad = 16(h_{(n-1)(n+1)}+h_{n(n+1)}-2h_{(n-1)n}),\end{aligned}\ ] ] from which we gain @xmath249 and @xmath250 . \3 . then , iterate the following steps for @xmath251 , @xmath252 & = 2h_{m(m+1)(n+1 ) } , \\ \i [ h_{m(m+1)},h_{m(m+1)(n+1 ) } ] & = 4(h_{m(n+1)}-h_{(m+1)(n+1)}),\end{aligned}\ ] ] to get @xmath253 ( @xmath254 ) . all the two - body operators involving the @xmath243th qubit are thus in our hands . \4 . combining the two - body operators , we can generate any three - body operators involving the @xmath243th qubit , @xmath255 = 2h_{m_1m_2(n+1)}\\ ( m_1,m_2=1,\ldots , n;\ m_1<m_2\le n).\end{gathered}\ ] ] in this way , all the rotationally symmetric two- and three - body operators for the first @xmath256 qubits are generated . then , by induction , we can generate all the rotationally symmetric two- and three - body operators for any number of qubits @xmath113 . let us estimate the asymptotic dimension for a large @xmath113 of the lie algebra @xmath258 in ( [ eqn : liechainsu ] ) generated by the projected hamiltonians @xmath156 and @xmath157 for the chain of @xmath113 qubits discussed in sec . [ sec : chain ] . as commented in sec . [ sec : chain ] , the dimension of @xmath258 is bounded by the dimension of @xmath165 and the dimension of @xmath171 , i.e. , @xmath259 as we will see , the lower bound is dominated by the first contribution @xmath260 for large @xmath113 , and the difference between the lower and upper bounds becomes relatively negligible in the asymptotic regime . observe also that the dimensions @xmath167 of the dfs s given in ( [ eqn : djn ] ) can be cast as @xmath261 where @xmath262 denotes the largest integer not greater than @xmath263 . approximating the binomial coefficient by @xmath264,\ ] ] the dimension of the lie algebra is estimated as @xmath265\\ & \sim \frac{4^n}{\sqrt{\pi}n^{3/2}},\end{aligned}\ ] ] where the continuum limit is taken through @xmath266 . here we derive the lower bound . using the definition of the hilbert - schmidt norm @xmath268 for a matrix @xmath145 we can rewrite the left - hand side of , @xmath269 where @xmath198 denotes the partial trace over the second system and the properties of the normalized choi state @xmath139 were used , i.e. , @xmath270 , @xmath271 , and @xmath272 for a unitary map . the third term of the right - hand side of can be rewritten as @xmath273 where from the second line to the third the cauchy - schwarz inequality and from the third line to the fourth the inequality between the arithmetic and the geometric means have been used . combining and we arrive at @xmath274 which is the desired result . note that for pure unitary maps @xmath275 the lower bound simplifies further @xmath276

on the basis of the quantum zeno effect it has been recently shown [ d. k. burgarth _ et al . _ , nat . commun . * 5 * , 5173 ( 2014 ) ] that a strong amplitude damping process applied locally on a part of a quantum system can have a beneficial effect on the dynamics of the remaining part of the system . quantum operations that can not be implemented without the dissipation become achievable by the action of the strong dissipative process . here we generalize this idea by identifying decoherence - free subspaces ( dfs s ) as the subspaces in which the dynamics becomes more complex . applying methods from quantum control theory we characterize the set of reachable operations within the dfs s . we provide three examples which become fully controllable within the dfs s while the control over the original hilbert space in the absence of dissipation is trivial . in particular , we show that the ( classical ) ising hamiltonian is turned into a heisenberg hamiltonian by strong collective decoherence , which provides universal quantum computation within the dfs s . moreover we perform numerical gate optimization to study how the process fidelity scales with the noise strength . as a byproduct a subsystem fidelity which can be applied in other optimization problems for open quantum systems is developed .

quantum information processing ( qip ) based on solid - state materials has attracted much attention over past few years due to the potential of scalability . since the qubits are encoded in individual electron spins in most of the solid - state qip schemes , how to efficiently detect a single electron spin has recently become a focus . although there is no fundamental restriction for the single spin detection , it seems that , to do the qubit readout very well , we are expecting further development of detection technique with sufficient spatial and temporal resolution . some preliminary experiments have reached the single spin level so far . for example , scanning- tunneling- microscope ( stm ) electron spin resonance ( esr ) has demonstrated single molecule esr spectroscopy of iron impurities in silicon @xcite , although theoretical work remains to clarify for the best description of the effects @xcite . a very recent stm experiment under low temperature and with a high magnetic field has shown the spin flip spectra of a single manganese atom @xcite , and the magnetic resonance force microscope , which utilizes a cantilever driven by spins oscillating in resonance , has successfully detected a single surface electron spin @xcite . moreover , it has been reported that micro - superconducting quantum interference devices are capable of distinguishing large spin difference ( @xmath0 ) @xcite . there have been some theoretical proposals for single spin detection in the candidate systems of qip @xcite . the present work will focus on the detection of a single electron spin of an encapsulated atom inside a fullerene ( i.e. , c@xmath1 ) , which corresponds to the readout of a qubit in performance of quantum computing based on the endohedral fullerenes @xmath2 or @xmath3 @xcite . the electron spin inside the fullerene plays the role of a qubit or an auxiliary qubit . as the electrons of the doped atoms can not escape the @xmath4 cage while preserving their spin states , we must develope special proposals for the spin detection , different from in @xcite . in fact , there have been some schemes in this respect , for example , by using a modified single molecule transistor ( smt ) @xcite , by a nanomagnet molecule fe@xmath5 @xcite , and by a shuttling device @xcite . however , no relevant experiment has been achieved yet . in the present paper , we investigate the possibility to detect a single electron spin inside the fullerene by stm . stm is a mature technique available to manipulate single atoms with high precision at low temperature @xcite . although no reliable evidence has been shown to achieve a single spin detection , there have been some experiments @xcite and theoretical proposals @xcite regarding single spin problems with the stm . our scheme is different from those proposals in following points : first , the electron spin to be detected , in our case , is assumed to be well polarized along an always - on magnetic field , while we do nt know whether the spin is up- or down- polarized . this corresponds to the final result of a real quantum computing , i.e. , the qubits returning to product states from entanglement and superposition after the elaborately designed logic gates have been carried out . so our detection is to know the orientation of the spin polarization . second , as the tunneling through the air is different from that through a fullerene , our treatment is to separate the whole tunneling process into three consecutive steps . third , due to the c@xmath1 cage , the local electron spin ( i.e. , the spin to be detected inside the cage ) is well protected . as a result , different from the case in @xcite with the electron spin on the surface , the main error in our case is from the vibration of the fullerene , instead of the spin scattering , due to the tunneling electrons . the conditions we employ in the treatment below include coulomb blockade @xcite and the polarized current in stm @xcite , both of which have been achieved experimentally . the coulomb blockade restricts the fullerene to be charged by no more than one electron , which means an electron from the stm tip could jump on the c@xmath1 only after the previous electron sitting on the c@xmath1 has jumped away . this has been demonstrated in a recent experiment @xcite for smt . so we will suppose that this coulomb blockade works throughout our scheme under a suitable bias voltage of the stm . the polarized current in stm implies that the electrons going out of the stm tip are well polarized , i.e. , up or down - polarized . it is reported in @xcite that the high - quality polarized current is already available in stm . so we suppose below that the tunneling electrons out of the stm tip are up - polarized . in the presence of a magnetic field , the tunneling electrons will couple to the caged electron by exchange interaction due to the spin degrees of freedom involved @xcite . moreover , the total electron spin of the doped atom n or p are @xmath6 with four zeeman levels @xmath7 and @xmath8 @xcite . it has been demonstrated that quantum gating can be performed independently with electron spin states @xmath7 or @xmath8 @xcite . for simplicity , however , we will focus below on the discussion about the caged electron spins @xmath8 . the case regarding @xmath7 could be obtained simply by enlarging the variation of the tunneling current by three times . in the next section , we will explore the spin - dependent tunneling matrix elements . then a specific calculation of the tunneling will be made in sec iii which also includes discussions about the experimental imperfection . the last section is for the conclusion . to clarify our description below , we simplify the system shown in fig . 1 to be a doped fullerene sandwiched by two leads l and r , as shown in fig . so the hamiltonian is , @xmath9 where @xmath10 ( @xmath11 ) creates ( annihilates ) an electron in the lead @xmath12 , with @xmath13 being the momentum of the electron , @xmath14 for ( up / down ) spin polarization , and @xmath15 are energies regarding fermi energy . the operator @xmath16 ( @xmath17 ) is related to the electron on the fullerene in the orbital @xmath18 . @xmath19 is the tunneling coefficient regarding @xmath20 l or r. @xmath21 accounts for the fullerene including the energy of itself and the coulomb blockade term @xmath22 as well as the exchange coupling @xmath23 with @xmath24 and @xmath25 the spin degrees of freedom of the electrons outside and inside the fullerene , respectively . since our interest is in the tunneling modification due to the electrons exchange interaction , instead of the electro - phonon @xcite or spin - phonon resonances , we may follow the idea in @xcite and focus on the spin dependent tunneling matrix elements . to this end , we separate the tunneling into three steps ( see fig . 2 ) : the first step is from the left lead to the fullerene , the second one is for tunneling through the fullerene , and the third accounts for the tunneling from the fullerene to the right lead . both the first and the third steps can be modeled as electronic tunneling through capacitors with @xmath26 where @xmath27 , @xmath28 is the work function , @xmath29 is the tunneling gap , and @xmath30 represents the constant regarding the free space permittivity , the dielectric constant and the area of the lead . by using wkb approximation , we could reach the spin - dependent tunneling matrix elements as below @xcite , @xmath31 and @xmath32 where @xmath33 is the strength for the exchange coupling between the tunneling electrons and the caged electron due to the spin degrees of freedom of the electrons , which is proportional to the integral below @xmath34 with @xmath35 and @xmath36 the wavefunctions of the electrons tunneling and caged at the position @xmath37 and @xmath38 , respectively , and @xmath39 . for simplicity , we have omitted in eqs . ( 2 ) and ( 3 ) the unimportant constants regarding the spin independent tunneling rate in the absence of @xmath33 . please note , we have also made an assumption here that , due to the coulomb blockade and the low temperature limits , each electron from the left lead would jump to the ground state of @xmath40 and the tunneling amplitude is mainly dependent on the exchange interaction , instead of the electronic momenta . since both spins of the tunneling and caged electrons are well polarized , we may simplify @xmath41 to be @xmath42 with @xmath33 being 1 mev @xcite . as a result , straightforward algebra for eq . ( 2 ) yields corresponding tunneling rates , @xmath43\ } \\ & \approx & \exp \{- \frac { 2}{3}\sqrt { \frac { 8mw_{1}}{\hbar^{2 } } } x_{1}^{3/2 } ( 1\pm \frac { 3j}{2w_{1}x_{1}})\},\end{aligned}\ ] ] where the signs @xmath44 correspond to the up / down polarization of the caged electron spin . we have approximately omitted in above equation the high - order terms regarding @xmath45 because they are comparatively negligible ( i.e. , @xmath46 to the numbers shown later ) . similarly , we have @xmath47\ } \\ & \approx & \exp \{-\frac { 2}{3}\sqrt { \frac { 8mw_{3}}{\hbar^{2 } } } x_{3}^{3/2 } ( 1\pm \frac { 3j}{2w_{3}x_{3}})\ } \exp \{\frac { 2}{3}\sqrt { \frac { 8mw_{3}}{\hbar^{2 } } } x_{2}^{3/2 } ( 1\pm \frac { 3j}{2w_{3}x_{2}})\}. \end{aligned}\ ] ] the second step can be considered as a tunneling through a constant potential barrier . this is because the fullerene could be modeled as a spherical capacitor . due to the equipotential surface of the spherical capacitor , the work function @xmath48 should be a constant , which yields the tunneling rate as @xmath49 since @xmath33 is smaller than @xmath28 by 1000 times , we may write the terms regarding @xmath33 as @xmath50 where @xmath51 is from @xmath52 , @xmath53 and @xmath54 are from @xmath55 , and @xmath56 is from @xmath57 . since the tunneling current is proportional to the multiplication of the tunneling rates above , we may simply write the tunneling current as @xmath58 where @xmath59 is the spin independent tunneling current , which could be detected in the absence of the magnetic field . in the following calculation , we assume @xmath60 to be 1 na @xcite if @xmath61 nm . from @xcite we know that , @xmath62 nm is the size of the fullerene , and @xmath63 nm is due to van der waals interaction between the fullerene and the substrate . we suppose that @xmath64 is 2 ev between @xmath65 and @xmath66 , @xmath67 ev is constant , and @xmath68 ev is from @xmath69 to @xmath70 . then we can obtain by direct calculation that @xmath71 pa , where @xmath72 corresponds , respectively , to @xmath44 in eq . the current of 16 pa is detectable with the present stm technology . slightly changing @xmath73 , we may estimate @xmath74 , which changes drastically with respect to @xmath73 , as shown in fig . so it is evident that the difference between spin - up and spin - down of the caged electron is distinguishable from the tunneling current as long as @xmath73 is around 0.24 nm . as mentioned above , because the local spin in our case is pretected by the fullerene cage , the main source of error is the vibration of the fullerene due to the tunneling electrons , which yields a shift @xmath75 pm equivalent to the energy variation 5 mev @xcite . because this vibrational degree of freedom is far detuned from other characteristic frequencies , and also because there is no evidence of vibration - spin coupling , we did not consider this vibration in above treatment . the tunneling current , however , is very sensitive to the distance variation . so we have to strictly assess the influence due to the position shift of the fullerene on the tunneling current . to this end , we consider the tunneling gaps regarding the first and the third steps to be changed time - dependently , while the second step remains unchanged . so we have the modification of the tunneling rates , @xmath76 @xmath77 suppose @xmath78 with @xmath79 thz @xcite . like in @xcite , we introduce the average current over the time @xmath80 , i.e. , @xmath81 , where the sum from @xmath82 to n is over the number of the tunneling electrons in the time @xmath80 , and @xmath83 is proportional to the tunneling rate for each electron . so @xmath84 can be written as @xmath85[1 \pm d_{3}\ ] ] @xmath86.\ ] ] as the terms regarding @xmath87 are comparable to @xmath88 , we have to eliminate the vibrational influence . to this end , we may detect the current during a time period @xmath89 with @xmath90 , in order to average out the terms regarding @xmath91 . this would in principle make the fullerene vibration , due to the tunneling of the electrons , of negligible effect on the original current in our observation . however , due to the intrinstically stocastic property of the electron tunneling , the efficiency of above trick depends on the statistical deviation @xmath92 of a normal distribution @xmath93}$ ] , where @xmath94 is the mean tunneling time of each electron we desire @xcite . to carry out our scheme to the best , we require @xmath92 to be as small as possible . besides , there are other possible imperfection in implementing our scheme . in a real quantum computing , the qubits are not usually well polarized at the end of the computing operations . for example , the c@xmath1-caged electron - spin would probably be in superposition @xmath95 ( @xmath96 or @xmath97 ) due to some unpredictable error sources in quantum computing . the estimated current dispersion due to this imperfect polarization is @xcite , e.g. , @xmath96 , @xmath98 in which @xmath99 is much smaller than 1 and @xmath100 is of the order of hundred in an observation during a period of @xmath101100 ns . so this current dispersion is too small to affect our spin detection . in addition , the feedback effect of the tunneling electrons on the caged spin should also be addressed . this estimate could be done by fermi golden rule from the second - order perturbation @xcite , which yields the spin decay rate @xmath102 with @xmath103 the tunneling rate of the electrons . as we suppose @xmath104 na , implying @xmath105 hz , we have @xmath106 sec , which is much longer than our detection time . so this spin decay is also negligible . normally , the tunneling current in usual use of stm is from the order of pa to na , which implies that the tunneling rate of the mobile electrons is from one electron every 100 ns to one electron every 100 ps . we have noticed that the observation of individual electron - jump is within the reach of the current technique by i - v characteristic and by di / dv plot @xcite , and the minimum current the stm is able to distinguish is of the order of 0.1 pa @xcite . recent experiment @xcite has shown the availability of a controllable manipulation of a single c@xmath1 by stm . moreover , in the absence of the tunneling of the electrons outside the fullerene , the decoherence time of the caged electron - spin is about 1 second at 7@xmath107 k @xcite , much longer than our implementation time . so decoherence is neglected in our treatment above . while there is no experimental data for dephasing of the tunneling electrons . a recent work @xcite has shown that the spin dephasing time of the bulk two - dimensional electron gas at low temperature could be 150 ns . in our case , we require the dephasing time of the tunneling electrons to be longer than 100 ns . considering the data in @xcite and the difference between the bound and unbound electrons , our requirement should be satisfied at very low temperature . compared with a previous work @xcite using a modified smt , the present scheme is , to some extent , similar , but much simpler . in @xcite , spin flips of the mobile electrons by microwave pulses are necessary . since the electron tunneling is intrinsically stocastic , the decoherence due to imperfect spin flip yields the main infidelity . in contrast , no spin flip is needed in the present scheme . so the dephasing of the mobile electron is not a serious problem in our scheme . furthermore , a magnetic field gradient @xmath108 t / m is essential to @xcite . while such a magnetic field being highly stable in time and very large and homogeneous in spatial gradient is still challenging with the present technique . in contrast , the constant magnetic field required in the present scheme is fully within the reach of the current technique . shortly speaking , the present scheme is better than in @xcite , and the advantages are from a combination of stm and smt : stm makes sure that the tiny variation of the current can be distinguished , and the coulomb blockade in smt experiment guarantees that the change of the tunneling current corresponds to the fullerene charged by only a single polarized electron . in summary , we have explored the possibility to detect the electron spin of the doped atom in a fullerene cage by stm , assisted by the coulomb blockade and polarized current . different from previous studies , we separated the whole tunneling process into three parts . after presenting the spin dependent tunneling matrix elements , we have shown by specific calculation the feasibility of this detection with current stm technique . the detrimental influences from some imperfect factors have also been considered in our treatment . since the stm is widely employed in atomic and molecular control in various systems , we argue that the main idea of the present work , i.e. , the use of the stm device along with the coulomb blockade and the polarized current could be in principle applied to other candidate systems of qip for detection of a single electron spin . this work is supported in part by grants from hong kong research grants council ( rgc ) and the hong kong baptist university faculty research grants ( frg ) . mf also acknowledges thankfully the support from nnsfc no . 10474118 . 27 y. manassen , i. mukhopadhyay and n.r . rao , phys . b * 61 * , 16223 ( 2000 ) ; y. manassen , e. terovanesyan , d. shachal , and s. rivhter , phys . rev . b * 48 * , 4887 ( 1993 ) . a.v . balatsky and i. martin , eprint , cont - 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matt/0605075 . a.v . balatsky , y. manassen , and r. salem , phlo . b * 82 * , 1291 ( 2002 ) . balatsky , y. manassen , and r. salem , phys . b * 66 * , 195416 ( 2002 ) . z. nussinov , m.f . crommie , and a.v . balatsky , phys . b * 68 * , 085402 ( 2003 ) . h. park _ et al _ , nature , * 407 * , 57 ( 2000 ) . s. heinze _ et al _ , science * 288 * , 1805 ( 2000 ) . f. elste and c. timm , phys . b * 71 * , 155403 ( 2005 ) . m. feng and j. twamley , phys . a * 70 * , 032318 ( 2004 ) . utami , h .- s . goan and g.j . milburn , phys . b * 70 * , 075303 ( 2004 ) . it is a common understanding from the standard text book of quantum mechanics that the wkb method yields the tunneling amplitude to be proportional to @xmath109 , where @xmath110 and @xmath111 are , respectively , the potential barrier and the energy of the tunneling particles . due to spin degrees of freedom involved , the potential is spin dependent in our case . so like in @xcite , we replace @xmath112 by @xmath113 with @xmath114 and @xmath33 being work function and the strength of the exchange coupling , respectively . the difference in expressions of the tunneling matrix elements in @xcite from ours here is due to the constant potential barrier supposed in their treatment . y. noguchi _ et al _ , current appl . phys . * 3 * , 397 ( 2003 ) . private communication with professor g.y cao . r. yamachika _ et al _ , science * 304 * , 281 ( 2005 ) . v.n . golovach and d. loss , semicond . . technol . * 17 * , 355 ( 2002 ) . fig . 1 schematic of the detection of a single caged electron spin by stm , where the black dots mean the electrons , and @xmath115 and @xmath116 correspond to the spin degrees of freedom regarding the electrons tunneling and caged , respectively . the caged electron spin can be @xmath117 or @xmath118 , which pair of spins employed in quantum computing has been known before the detection . so what we want to detect is whether the spin is up ( i.e. , 1/2 or 3/2 ) or down ( i.e. , -1/2 or -3/2 ) . the gap between the fullerene and the substrate is due to van der waals interaction @xcite .

we consider to detect the electron spin of a doped atom , i.e. , a nitrogen or a phosphorus , caged in a fullerene by currently available technique of the scanning tunneling microscope ( stm ) , which actually corresponds to the readout of a qubit in the fullerene - based quantum computing . under the conditions of polarized stm current and coulomb blockade , we investigate the tunneling matrix elements involving the exchange coupling between the tunneling polarized electrons and the encapsulated polarized electron , and calculate the variation of the tunneling current with respect to different orientations of the encapsulated electron spin . the experimental feasibility of our scheme is discussed under the consideration of some imperfect factors . 0.1 cm

no food or drinks are to be taken from dawn to sunset . according to some interpretations , taking of oral medicine is also forbidden during these hours . in the evening , the fast is broken with sweet drinks and snacks . if a muslim misses a day of fasting , ( s)he has to make up for it on a later day and often pay a penalty , which is used to feed the poor . certain people are excluded from this religious obligation to fast , including children under 12 , the sick , the traveling and women who are pregnant / breastfeeding young babies/ having their menstrual period . although sick persons are exempted from fasting , many still wish to keep the fast and force the doctor to allow them to do so . for people who are eligible / allowed not to fast in islam , some individual still feel the obligation to pay compensation may play a role in the economically weak patient wanting to keep the fast , as also in orthodox areas , negative reactions from other people may do the same . in these situations adrenal insufficiency can result from structural or functional lesions of the adrenal cortex ( primary adrenal insufficiency or addison 's disease ) or from structural or functional lesions of the anterior pituitary or hypothalamus ( secondary adrenal insufficiency ) . in developed countries , primary adrenal insufficiency is most frequently secondary to autoimmune adrenal disease , whereas tuberculous adrenalitis is the most frequent etiology in underdeveloped countries . other causes include adrenalectomy , bilateral adrenal haemorrhage , neoplastic infiltration of the adrenal glands , acquired immunodeficiency syndrome , inherited disorders of the steroidogenic enzymes , and x - linked adrenoleukodystrophy . secondary adrenal insufficiency resulting from pituitary or hypothalamic dysfunction generally presents in a more insidious manner than does the primary disorder , probably because mineralocorticoid biosynthesis is preserved . acute adrenal insufficiency disease is characterized by gastrointestinal symptoms ( nausea , vomiting , and abdominal pain ) , dehydration , hyponatremia , hyperkalemia , weakness , lethargy , and hypotension . it is usually associated with disorders of the adrenal rather than the pituitary or hypothalamus , and sometimes it follows abrupt withdrawal of glucocorticoids used at high doses or for prolonged periods . in the month of ramadan , a person keeping a fast refrains from eating and drinking during daylight hours , which is approximately 15 hours . during ramadan , the dietary pattern is also changed and in comparison to other days , people consume more oily and spicy items and sugar preparations at iftar . also at iftar parties , the chances of food and water contamination are higher , due to mass production of food and usually an unhygienic practice while serving . thus , a person suffering from adrenal insufficiency , in order to avoid adrenal crisis , should be advised regarding food habits , drug compliance , and warning signs properly . we recommend the following guidelines for patients suffering from adrenal insufficiency , who wish to keep the fast . the preferred drug for adrenal insufficiency is hydrocortisone , but as we know , the biological half - life of hydrocortisone is short ( half - life < 12 hours ) and the fasting hours are longer ( about 15 hours ) , therefore , longer acting glucocorticoids like prednisolone or dexamethasone may be considered as per patient compliance during the month of ramadan . also a combination of prednisolone in the morning and hydrocortisone in the evening may be considered to match the cortisol day curve . if possible , this drug replacement may be started a few weeks before ramadan and the patient should be monitored as per clinical symptoms ( e.g. , energy level , fatigue ) and signs like blood pressure , for proper dose adjustment . the timing of corticosteroid intake during iftar and sahar should be adjusted in such a manner that the interval between the two doses matches the cortisol day curve as much as possible . measurements of plasma adrenocorticotropic hormone ( acth ) and / or serum cortisol are not routinely necessary . in secondary adrenal insufficiency , mineralocorticoid replacement is not required , while in primary adrenal insufficiency the mineralocorticoid dose should be adjusted according to the corticosteroid preparation , as hydrocortisone has both glucocorticoid and mineralocorticoid activity , but the mineralocorticoid activity of prednisolone is lesser than hydrocortisone and that of dexamethasone is zero . the anti - inflammatory action of cortisol is 1 and that of prednisolone is 3 , while that of dexamethasone is 26 . monitoring for dose adjustment may be done with serum na , k , and blood pressure control.[26 ] due to consumption of oily foods and steroids , the patients should take proton - pump inhibitors , in order to prevent gastritis , if and when required . patient education is an important part of management ; they should be clear about warning symptoms of adrenal insufficiency , like fatigue , nausea and / or vomiting . it is also wise to share this information with the family , friends , and any caregivers , so that they can also identify signs of trouble and be prepared to act in case of adrenal crisis . the patients should be advised to carry their emergency medical information card that lists the doses of their daily medications and the names of their physician and family member(s ) , to call in case of an emergency . as a safety measurement , the patients should always carry a syringe and a vial of hydrocortisone or dexamethasone with them , and also safely store these at home . the patient should be able to take extra dosage of steroid if / when signs / symptoms of adrenal insufficiency appear but in addition family member or friend should know how to give give the steroid injection into a muscle ( usually the thigh ) during an episode of adrenal crisis especially if the person is found unconscious . following this the patients should be instructed to adjust the dosage ( double or triple their daily dose ) of corticosteroid during symptoms of stressful medical condition such as cold , flu , diarrhea or vomiting . as soon as illness is over and the symptoms have subsided they can return to taking their usual amount of medication . these patients should try their best to have proper meals and to avoid sugars , processed starches , caffeine , stimulant drugs , and as much as nicotine as possible . as a majority ( 75% ) of primary adrenal insufficiency patients are salt - wasters , they should be advised to avoid exertional activity and to not spend more time in a hot climate during fasting hours . during non - fasting hours they should be sure to drink enough non - sugar - laden liquids and supplement them with enough salt to alleviate a dangerous situation . the patients should look for ankle edema , which may be due to insufficient salt , but usually disappears in about two to three days after taking adequate salt . they should avoid or reduce excessive heat , cold , overwork , lack of sleep , and arguments . they should try to take rest for longer periods during fasting hours , with proper sleep at night , in order to reduce stress . if deemed medically necessary , patients should be advised not to keep a fast . but patients who refuse to follow instructions ( against medical advice ) , must be advised regarding the suitable drugs for that particular period , the warning signs , sick - day management , physical activity , and dietary limits . they should also be advised to treat themselves appropriately whenever a warning sign is present .

adrenal insufficiency is a life - threatening event , so it is recommended for patients with known adrenal insufficiency to be properly educated regarding sick - day management . in the month of ramadan , people refrain from eating and drinking during daylight hours . it is very important for patients with adrenal insufficiency , who wish to keep a fast , to be well aware of the disease , the suitable drug to be used for that particular period , warning signs , sick - day management , physical activity , and dietary limits . this article describes guidelines for the sick - day management of patients with adrenal insufficiency , in the month of ramadan .

pomegranate has been considered a fruit tree species of minor importance , but the increased consumer demand for exotic fruits as well as for high nutritional quality foods opens new perspectives for consumption of that traditional species . pomegranate seeds , the edible portion of the fruit , are rich in sugars , vitamins , polysaccharides , polyphenols , and minerals . they have low oil content and are rich in polyunsaturated ( n-3 ) fatty acids . the antioxidant capacity of commercial pomegranate juice is three times higher than those of red wine and green tea . the antioxidant qualities of pomegranate juice make it appealing for the production of health supplements and nutraceuticals . the antioxidant activity was suggested to be related , in part , to the three major anthocyanidins found in pomegranate seed extract . therefore evaluation of the anthocyanin content in food products is very important . at present , various methods for anthocyanin quantification are used . in pomegranate juice , anthocyanin content is determined usually according to the method developed by gil et al . besides the quantification method , the anthocyanin content also depends on factors like species , varieties , maturity index , seasonal conditions , processing type , or storage conditions of the food products [ 3 , 5 , 7 ] . application of various anthocyanin extraction methods also influences the evaluation of antioxidant activities of extracts . in the present paper , two quantification methods of anthocyanins as well as the influence of storage conditions on anthocyanin sweet pomegranates ( punica granatum cultivator assaria ) were harvested in an orchard in eastern algarve ( portugal ) . fruits were transported , on the same day , to the laboratory at the university of algarve . after selection ( diseased , bruised , and injured fruits were rejected ) , healthy fruits of uniform size and appearance were randomly distributed into alveolated boxes and stored in 4 modalities of fruit covering . the fruits were subjected to several treatments ; treatment 1 : control ( no covering ) ; treatment 2 : wax coating by spraying fruits with brillaqua wax emulsion ( polyethylene wax ( 3.8% ) ( w / w ) , shellac ( 1.5% ) ( w / w ) , and wood resin ( 10% ) ( w / w ) , from brillaqua , valencia , spain ) ; treatment 3 : covering boxes with a 25 c low - density polyethylene film ; treatment 4 : 1.5% cacl2 fruit spraying ; treatment 5 : 1.5% cacl2 and brillaqua wax emulsion ( combination of treatments 2 and 4 ) . the fruits were stored at 5c . at harvest and monthly , for 4 months , 10 fruits of each replication were removed and the concentration of anthocyanins was measured . for each sampling point , there were 4 replications . the juice sample ( 1 ml ) was centrifuged ( 2 minutes at 10 000 rpm ) and filtered through a 0.45 m filter . the identification of anthocyanins was performed by hplc with a detector uv - vis beckman 166 ( usa ) , using a li - chrochart 100 rp-18 column ( 25 cm 0.4 cm inner diameter ; 5 m particle size , merck ( usa ) ) . the mobile phase was 5% formic acid ( a ) and methanol ( b ) in a linear gradient starting with 15% b to reach 35% b in 15 minutes , then isocratic until 20 minutes , at a flow rate of 1 ml / min . injection volume was 20 l using an injector with a 20 l loop ( rheodyne , calif , usa ) . anthocyanins were identified by comparison of their retention times with those of pure standards . to quantify total concentration of anthocyanins , two methods were used . method 1 : the concentration of anthocyanins was calculated from their peak areas in the chromatograms and compared with an external standard of cyanidin-3-rutinoside as previously reported . method 2 : anthocyanins were identified and quantified individually based on standard curves of each anthocyanin type : delphinidin 3 , 5-diglucoside ( dp3 , 5 ) , delphinidin 3-glucoside ( dp3 ) , cyanidin 3 , 5-diglucoside ( cy3 , 5 ) , cyanidin 3-glucoside ( cy3 ) , pelargonidin 3 , 5-diglucoside ( pg3 , 5 ) , and pelargonidin 3-glucoside ( pg3 ) , at four concentrations ( 0.01 , 0.02 , 0.04 , and 0.08 mg total amount of anthocyanin in the samples was calculated as the sum of the mean of individual pigments . sweet pomegranates ( punica granatum cultivator assaria ) were harvested in an orchard in eastern algarve ( portugal ) . fruits were transported , on the same day , to the laboratory at the university of algarve . after selection ( diseased , bruised , and injured fruits were rejected ) , healthy fruits of uniform size and appearance were randomly distributed into alveolated boxes and stored in 4 modalities of fruit covering . the fruits were subjected to several treatments ; treatment 1 : control ( no covering ) ; treatment 2 : wax coating by spraying fruits with brillaqua wax emulsion ( polyethylene wax ( 3.8% ) ( w / w ) , shellac ( 1.5% ) ( w / w ) , and wood resin ( 10% ) ( w / w ) , from brillaqua , valencia , spain ) ; treatment 3 : covering boxes with a 25 c low - density polyethylene film ; treatment 4 : 1.5% cacl2 fruit spraying ; treatment 5 : 1.5% cacl2 and brillaqua wax emulsion ( combination of treatments 2 and 4 ) . the fruits were stored at 5c . at harvest and monthly , for 4 months , 10 fruits of each replication were removed and the concentration of anthocyanins was measured . for each sampling point , there were 4 replications . pomegranates were manually peeled and the seeds liquefied by hand . the tegmina were discarded . the juice sample ( 1 ml ) was centrifuged ( 2 minutes at 10 000 rpm ) and filtered through a 0.45 m filter . the identification of anthocyanins was performed by hplc with a detector uv - vis beckman 166 ( usa ) , using a li - chrochart 100 rp-18 column ( 25 cm 0.4 cm inner diameter ; 5 m particle size , merck ( usa ) ) . the mobile phase was 5% formic acid ( a ) and methanol ( b ) in a linear gradient starting with 15% b to reach 35% b in 15 minutes , then isocratic until 20 minutes , at a flow rate of 1 ml / min . injection volume was 20 l using an injector with a 20 l loop ( rheodyne , calif , usa ) . anthocyanins were identified by comparison of their retention times with those of pure standards . to quantify total concentration of anthocyanins , two methods were used . method 1 : the concentration of anthocyanins was calculated from their peak areas in the chromatograms and compared with an external standard of cyanidin-3-rutinoside as previously reported . method 2 : anthocyanins were identified and quantified individually based on standard curves of each anthocyanin type : delphinidin 3 , 5-diglucoside ( dp3 , 5 ) , delphinidin 3-glucoside ( dp3 ) , cyanidin 3 , 5-diglucoside ( cy3 , 5 ) , cyanidin 3-glucoside ( cy3 ) , pelargonidin 3 , 5-diglucoside ( pg3 , 5 ) , and pelargonidin 3-glucoside ( pg3 ) , at four concentrations ( 0.01 , 0.02 , 0.04 , and 0.08 mg total amount of anthocyanin in the samples was calculated as the sum of the mean of individual pigments . the total anthocyanin concentration in the assaria pomegranate juice determined by two different quantitative methods , method 1 and method 2 , monitored over 4 months of storage , is presented in figures 1 and 2 . application of two quantification methods resulted in obtaining different results : the concentration of anthocyanins was always 2-fold higher when cyanidin 3-rutinoside , as external standard , was used . both methods showed that during the first month of storage , an increase of the total anthocyanin level occurred in all treatments , reaching a maximal value at the end of the first month of storage with the exception of fruits treated with cacl2 . the highest concentration was found in the fruits treated with wax , independent of the quantification method used ( 439.0 mg / l and 210.9 mg / l for methods 1 and 2 , respectively ) . in the fruits treated with cacl2 , the maximal concentration of anthocyanins was obtained only after two months of storage ( 307.2 and 155.4 mg / l , for methods 1 and 2 , respectively ) . at the end of the first month of storage , these fruits showed the lowest levels of anthocyanins ( 236.5 and 113.3 mg / l , respectively ) . during the second , third , and fourth months of storage in all treatments , with the exception of cacl2 treatment , significant decrease in anthocyanin levels the same tendency was observed with the cacl2 treatment in the third and fourth months of storage . nevertheless , the anthocyanin amount still remained above the initial values in all treatments . six anthocyanins were detected in the assaria pomegranate juice : delphinidin 3-glucoside ( dp3 ) , cyanidin 3-glucoside ( cy3 ) , pelargonidin 3-glucoside ( pg3 ) , delphinidin 3 , 5-diglucoside ( dp3 , 5 ) , cyanidin 3 , 5-diglucoside ( cy3 , 5 ) , and pelargonidin 3 , 5-diglucoside ( pg3 , 5 ) . figures 3a and 3b represent the time course of concentration of each anthocyanin in the control fruits , using the quantitative methods 1 and 2 , respectively . application of both methods showed that the levels of pg3 and pg3 , 5 were very low in comparison to the remaining anthocyanins . thus , when the levels of anthocyanins were calculated based on cyanidin-3-rutinoside as an external standard , dp3 , 5 was the major anthocyanin present in samples ( figure 3a ) . when the quantification was obtained from standard curves of each pigment , dp3 was the dominating anthocyanin ( figure 3b ) . in both methods , the same evolution profile of anthocyanins was observed : higher accumulation of anthocyanins during the first storage month followed by their decrease in the following months . evolution of total anthocyanin concentration in juice of the assaria pomegranate fruits , during storage at 5c , quantified by comparison with an external standard of cyanidin 3-rutinoside ( apin chemicals , uk ) . total amount of anthocyanins in the samples was calculated as the sum of the mean of individual pigments . evolution of total anthocyanin concentration in juice of the assaria pomegranate fruits , during storage at 5c , calculated from standard curves of dp3 , 5 ; dp3 ; cy3 , 5 ; cy3 , pg3 , 5 , and pg3 . total amount of anthocyanins in the samples was calculated as the sum of the mean of individual pigments . evolution of delphinidin 3 , 5-diglucoside ( dp3 , 5 ) , cyanidin 3 , 5-diglucoside ( cy3 , 5 ) , pelargonidin 3 , 5-diglucoside ( pg3 , 5 ) , delphinidin 3-glucoside ( dp3 ) , cyanidin 3-glucoside ( cy3 ) , and pelargonidin 3-glucoside ( pg3 ) concentration in assaria pomegranate juice from control fruits , during storage at 5c . ( a ) individual anthocyanins were quantified by comparison with an external standard of cyanidin 3-rutinoside ( apin chemicals ) . ( b ) the concentrations of anthocyanins were calculated from standard curves of dp3 , 5 ; dp3 ; cy3 , 5 ; cy3 , pg3 , 5 , and pg3 . evolution of delphinidin 3 , 5-diglucoside ( dp3 , 5 ) , cyanidin 3 , 5-diglucoside ( cy3 , 5 ) , pelargonidin 3 , 5-diglucoside ( pg3 , 5 ) , delphinidin 3-glucoside ( dp3 ) , cyanidin 3-glucoside ( cy3 ) , and pelargonidin 3-glucoside ( pg3 ) concentration in assaria pomegranate juice from fruits treated with brillaqua wax , during storage at 5c . the concentrations of anthocyanins were calculated from standard curves of dp3 , 5 ; dp3 ; cy3 , 5 ; cy3 , pg3 , 5 , and pg3 . evolution of delphinidin 3 , 5-diglucoside ( dp3 , 5 ) , cyanidin 3 , 5-diglucoside ( cy3 , 5 ) , pelargonidin 3 , 5-diglucoside ( pg3 , 5 ) , delphinidin 3-glucoside ( dp3 ) , cyanidin 3-glucoside ( cy3 ) , and pelargonidin 3-glucoside ( pg3 ) concentration in assaria pomegranate juice from fruits covered with polyethylene film , during storage at 5c . the concentrations of anthocyanins were calculated from standard curves of dp3 , 5 ; dp3 ; cy3 , 5 ; cy3 , pg3 , 5 , and pg3 . evolution of delphinidin 3 , 5-diglucoside ( dp3 , 5 ) , cyanidin 3 , 5-diglucoside ( cy3 , 5 ) , pelargonidin 3 , 5-diglucoside ( pg3 , 5 ) , delphinidin 3-glucoside ( dp3 ) , cyanidin 3-glucoside ( cy3 ) , and pelargonidin 3-glucoside ( pg3 ) concentration in pomegranate juice from fruits treated with 1.5% cacl2 , during storage at 5c . the concentrations of anthocyanins were calculated from standard curves of dp3 , 5 ; dp3 ; cy3 , 5 ; cy3 , pg3 , 5 , and pg3 . bars represent standard deviations of four replicates . evolution of delphinidin 3 , 5-diglucoside ( dp3 , 5 ) , cyanidin 3 , 5-diglucoside ( cy3 , 5 ) , pelargonidin 3 , 5-diglucoside ( pg3 , 5 ) , delphinidin 3-glucoside ( dp3 ) , cyanidin 3-glucoside ( cy3 ) , and pelargonidin 3-glucoside ( pg3 ) concentration in assaria pomegranate juice from fruits treated with 1.5% cacl2 plus brillaqua wax , during storage at 5c . the concentrations of anthocyanins were calculated from standard curves of dp3 , 5 ; dp3 ; cy3 , 5 ; cy3 , pg3 , 5 , and pg3 . bars represent standard deviations of four replicates . in order to make the results easier to interpret , hereafter the quantification of anthocyanins is made comparing the peak areas of each anthocyanin with those obtained from calibration curves of each standard stock solution ( method 2 ) . this methodology is the most adequate because the standards ' composition was close to that of the samples , as required in analytical chemistry . as mentioned earlier , the fruits treated with wax showed the greatest accumulation of anthocyanins after one month of storage ( figure 4 ) . among the anthocyanins monitored , dp3 was the major pigment . the maximal value reached after the first month of storage was 81.7 mg / l , and was superior to the control with 66.5 mg / l ( figure 3b ) . the polyethylene film treatment also induced a great accumulation of dp3 ( 58.0 mg / l ) during the first month of storage ( figure 5 ) . contrary to the significant changes in the levels of dp3 , 5 , cy3 , 5 , and cy3 , the variations of the cy3 , 5 level over time were lower . the fruits treated with cacl2 showed the lowest amounts of anthocyanins ( figure 6 ) . as mentioned earlier , the highest concentration was detected at the end of the second month of storage . the highest concentration of this pigment , observed at the end of the second month of storage , was 50.5 contrary to the treatments described above in which dp3 was the major pigment after one month of storage , two main pigments were detected in the fruits treated with cacl2 plus wax : cy3 , 5 ( 46.7 mg / l ) and dp3 ( 42.8 mg / l ) ( figure 7 ) . the anthocyanin profiles of some food products derived from red fruits are used to verify the authenticity and control the quality of these products . nevertheless , a great number of the laboratories that perform such analyses use their own methods . the most advisable method for quantitative chromatographic analysis involves the preparation of a series of standard solutions that approximate the composition of the unknown sample . this does not happen when cyanidin-3-rutinoside is used in the method that is frequently used by some authors for anthocyanin quantification in pomegranate juices . in the present paper , it was considered that applications of the standard solutions of each anthocyanin were more appropriate as the samples than the standard solution of cyanidin-3-rutinoside . therefore , the results were obtained comparing the peak areas with those obtained from the standard solutions of each anthocyanin , maintaining the same assay conditions . the anthocyanins present in pomegranate seeds of cultivator assaria were as those previously isolated and identified for cultivator a great variation of the amounts of dp3 , 5 , dp3 , and cy3 was registered over time , regardless of whether the levels of cy3 , 5 , were more stable . the variation was more evident between the harvesting time and the first month of storage , when a great increase of anthocyanin level was monitored , followed by decrease until the end of storage . previously , it was reported that dp3 , 5 and dp3 were the best substrates to undergo enzymatic oxidation for pomegranate cultivar mollar . this could partly explain the important decrease that was registered in the amounts of these anthocyanins in the assaria pomegranate juice . the increase in the total amount of anthocyanins during the first month of storage may be due to the continued biosynthesis of phenolic compounds after harvest , related to the ripening processes . the increase of anthocyanin concentration after harvest was reported previously in pomegranates [ 6 , 7 ] and that was correlated with the activity of the enzymes of the anthocyanin biosynthetic pathway : phenylalanine ammonia lyase ( pal ) and udp - glucose : flavonoid-3-o - glucosyltransferase ( gt ) . nevertheless , in juice of pomegranates stored in different atmospheres , holcroft et al observed that the increase in the total amount of anthocyanins was correlated with pal activity but not with gt activity . the pattern of anthocyanin content variation was distinct among the treatments during storage period . the greatest value was observed in wax treatment at the end of the first month but the fruits of that treatment presented the lowest content a month later . in contrast , the fruits treated with cacl2 that presented the greatest value in the second month had the lowest content in the first month . therefore , using the appropriate storage treatment , it is possible to have fruits with high anthocyanin content until two months after harvest . the effect of the different treatments could be related to changes in the fruit internal atmosphere . holcroft et al showed that in juice of pomegranates stored in air enriched with co2 , the anthocyanin concentration increased in time in both air - stored fruits and fruits stored in 10 kpa co2 , but remained stable for four weeks and subsequently decreased in fruits stored in 20 kpa co2 . in our work , the treatments used affected distinct biochemical mechanisms that could modify anthocyanin stability in different ways , making the treatment effect difficult to interpret . besides the storage treatments being very important for maintaining the external appearance , delaying senescence , and controlling decay of pomegranates , they can also contribute to increasing anthocyanin amounts during the first month of storage .

the concentration of anthocyanins in fruits of assaria pomegranate , a sweet portuguese cultivar typically grown in algarve ( south portugal ) , was monitored during storage under different conditions . the fruits were exposed to cold storage ( 5c ) after the following treatments : spraying with wax ; spraying with 1.5% cacl2 ; spraying with wax and 1.5% cacl2 ; covering boxes with 25 c thickness low - density polyethylene film . untreated fruits were used as a control . the anthocyanin levels were quantified by either comparison with an external standard of cyanidin 3-rutinoside ( based on the peak area ) or individual calculation from the peak areas based on standard curves of each anthocyanin type . the storage time as well as the fruit treatment prior to storage influenced total anthocyanin content . the highest levels were observed at the end of the first month of storage , except for the fruits treated with cacl2 , where the maximal values were achieved at the end of the second month . the anthocyanin quantification method influenced the final result . when total anthocyanin was calculated as a sum of individual pigments quantified based on standard curves of each anthocyanin type , lower values were obtained .

recent experiments have shown that long sequences of slidings of cylindrical blocks occurring on a rough incline submitted to small controlled perturbations give origin to nontrivial scaling laws for the measured length and lifetime distributions of events [ 1 - 3 ] . these slidings of blocks occur as an energy dissipation process on the interface block - incline to which the elastic energy is continuously input , and as a consequence , some connection between this problem and the nonlinear dynamics of earthquakes could be hypothesizing . the surge of interest observed in the last few years in problems involving rough surfaces is at one time the response to newly available experimental capacity [ 4,5 ] and simultaneously the embodiment and the driving force for a shift of attention towards the dynamical physics of complex phenomena typified by avalanches on sandpiles [ 6 - 8 ] , granular flow in general [ 9 - 12 ] , creep [ 13 ] , depinning transitions [ 14 ] , and friction in general [ 15 ] , among many others [ 16 ] . although the spatial scaling law observed with sliding of blocks in ref.1 be reminiscent of the gutenberg - richter law for the frequency of occurrence of earthquakes [ 17 ] , we can not state that the analogy between earthquakes and sliding blocks is well stablished . moreover , the distribution of duration of slidings [ 2 ] , and recent studies on effects of persistence and intermittency in these long time series [ 3 ] suggest in addition a complex structure for the distribution of sliding events along the time . earthquakes do not occur in a purely random way and seldom occur as isolated events , but are usually part of a sequence with foreshocks and aftershocks associated with a larger event called the mainshock . frequently the ( fore)aftershocks are defined so that the largest ( fore)aftershock in the sequence is typically one order of magnitude smaller than the mainshock . sequences of earthquakes not associated with a dominant event are called swarms . the decay of aftershock sequences obeys the omori law ( for his observation of it following the 1891 nobi earthquake ) which states that the rate @xmath0 of aftershocks at time @xmath1 after the mainshock decreases as a power law [ 17 ] . a similar omori law is also reported to appear in hydraulic fracturing [ 18 ] . this paper reports results on the time distribution of mechanical slidings of blocks on an inclined rough surface which are reminiscent of the omori law , although with a scaling exponent different from that observed for real earthquakes . the time series of mechanical sliding lengths \{@xmath2 } studied in this paper were obtained with the fully automatic 2000 mm long v - shaped aluminum incline with aluminum blocks used in ref.3 . this incline can be fixed at any angle @xmath3 with the horizontal with a precision of @xmath4 . the apparatus is held fixed on a table which is isolated from mechanical vibrations and temperature and humidity are constant . a laser assisted optical device measures the sliding lengths @xmath2 with a precision of @xmath5 and the data is stored and analyzed in a microcomputer . the discrete time @xmath6 here is defined by impacts of an electronic hammer which provides small controlled perturbations on the incline . twenty four series of slidings were studied in all , each one corresponding to a different angle of the incline . the total number of impacts in these series varied from @xmath7=500 to @xmath7=5000 and the number of impacts needed to move the solid block along a single full length of the incline varied from 182 to 700 . when the cylinder collides with the end of the groove , the last sliding is neglected and the cylinder is automatically placed on the top of the incline and a new chain of events initiates . for each one of these sequences , we chose the events with much larger magnitude than the average sliding length @xmath8 , and we identified them as the mainslidings ( ms ) of the series . some pairs of ms were selected and the total number of slidings @xmath9 between the nearest neighbors ms were recorded as a function of @xmath1 , with @xmath1=0 associated to the first ms . afterwards , events between ms with magnitude @xmath10 , were also recorded for different values of @xmath11 between 0.005 and 1.0 . sequences of swarm - like slidings although occurring in the experiments will not be studied in this work . of slidings observed between two mainslidings ( ms ) as a function of the number @xmath1 of impacts on the incline , in the domain of small angles in a single experiment ( @xmath12 in this case , and @xmath13 ) . the sliding lengths @xmath14 are given in mm , and the length(diameter ) of the aluminum block on the incline was 500mm(12 mm ) . the variable @xmath1 at the first ms , and the filter factor @xmath11 have the values @xmath15 and @xmath16 , respectively . the continuous line represents the best fit @xmath17 . the corresponding time series is shown in the upper - left - hand - corner inset . the bottom - right - hand - corner inset shows the time evolution of @xmath9 for six experiments in the domain of large inclinations . in this last situation @xmath18 . see text for details . ] if the angle @xmath3 which the incline forms with the horizontal is close to @xmath19 ( @xmath20 = coefficient of static friction ) in the interval @xmath21 , @xmath9 is observed to increase trivially as @xmath22 , with @xmath23 , as shown in the bottom - right - hand - corner inset of fig.1 with reduction factor @xmath24 for 6 typical sliding series . in this case the rate @xmath25 is simply the constant @xmath26 . a similar behavior was observed for all the other values of @xmath11 . on the other hand , for smaller angles in the interval @xmath27 , the sliding response of the block - incline system becomes complex and a large and variable number of mechanical perturbations ( and consequently of time units ) is needed before each sliding occurs ; i.e. the system in this domain of angles is much more slowly driven than in the phase of large angles . eight series in this domain of small angles were studied and a typical sequence of slidings between two ms ( @xmath14=46 mm at @xmath1=0 , and @xmath14=81 mm at @xmath1=376 ) is shown in the upper - left - hand - corner inset of fig.1 . the reader can observe in this figure that there is intermittency ( regions with bursts of sliding activity separated by regions without activity ) in the distribution of slidings ; i.e. slidings are no longer uniformly distributed as occurs for large angles . a detailed examination in the sequence of slidings of fig.1 shows that in 77@xmath28 of the total time span of this sequence the block does not move ( @xmath14=0 ) , and in the remaining 23@xmath28 there are 86 slidings . the average sliding length between the two ms in this particular case is @xmath29 = 1.35 mm ; thus the ms are much larger than @xmath30 for this sequence @xmath31 a similar proportion is valid for all sequences of slidings between ms studied in this paper . another interesting aspect of this inset lies in a fact that is commonly observed in real earthquake sequences : a high concentration of aftershocks following the ms and a low concentration of foreshocks before a ms . the central plot of fig.1 exhibits @xmath9 ( with @xmath24 ) for the sequence shown in the inset ; the solid line represents the best fit @xmath32 . the reader may observe that the main plot in fig.1 shows some discontinuities which are connected to the regions where the bursts of intermittency occur . this scaling behavior is independent of @xmath11 . the main plot of fig.2 exhibits the total number of afterslidings @xmath33 associated to the first ms of fig.1 for @xmath34 . the corresponding time series is shown in the inset of fig.2 . these slidings are restricted to the first half of the time interval shown in the inset of fig.1 , and satisfy @xmath35 . the best fit given by the continuous line in fig.2 has a slope of 0.73 , which is essentially the same slope observed in fig.1 within the typical experimental uncertainties of 5 - 10@xmath28 . the scaling exponent for aftershocks does not depend on the filter factor @xmath11 within the error bars . furthermore , if we focus our attention in the foreslidings of the second ms appearing in fig.1 ( i.e. in events distributed on the second half of the series shown in the inset of fig.1 ) , a similar scaling relation can again be obtained although with a higher level of statistical fluctuations due to the relative reduction in the number of events which characterizes this part of the sequence preceding a ms . is @xmath36 , and the continuous line has the slope 0.73 . see text for details . ] between nearest neighbors ms as a function of the time for all the experiments in the domain of small angles and for @xmath24 . the vertical bars give the statistical fluctuations . the straight line has the slope @xmath37 . ] , for the time series of fig.1 together with the adjust given by eq.3 ( continuous line ) : @xmath38 $ ] . ] different sequences of slidings give essentially the same exponent independently of the magnitude of the ms . in order to see how this works , we show in fig.3 the average number of slidings between two ms , @xmath39 , as a function of the time from the first ms , and the respective statistical fluctuations for all sequences of slidings studied . the solid line represents the best fit @xmath40 along two decades of variability in time . our overall estimate for the exponent @xmath41 is @xmath42 , as indicated by the fluctuation bars in fig.3 . within the margins of errors , no change of the scaling exponent was observed after variations of the value of @xmath11 , i.e. the power law in ( 1 ) is very robust irrespective of the filter factor . these results lead to a decay rate in the average number of slidings of blocks between pairs of ms as @xmath43 an expression reminiscent of the omori law for real earthquakes , although with a sensibly smaller exponent . the standard omori exponent is @xmath44 [ 17 ] . however , observations during the last decades [ 19@xmath3122 ] have pointed toward a generalized omori law in the form @xmath45 , with @xmath46 and @xmath47 constants , and @xmath48 , as an appropriate representation of the temporal variation of aftershock activity . the exponent @xmath41 in these cases differs from sequence to sequence , and it is presently not clear which factor is most significant in controlling this quantity . shaw [ 23 ] , in particular , derived the generalized omori law with scaling exponents close to one using a theory that involves the response to sudden forcing of a dynamics of self - driven acceleration to failure . recent advance in the theory of fracture and fragmentation has been invoked to explain empirical laws in seismology [ 24 ] . in this context , it is interesting to notice that eq.1 has an analogy in fragmentation dynamics , namely the scaling relation @xmath49 giving the ( average ) total number of fragments produced by the dynamics from some main fragment existing originally at @xmath1=0 . computer simulations [ 25 ] in these cases indicate that @xmath50 for 1d fragmentation controlled by diffusive processes . the numerical resemblance of the exponent @xmath51 with the exponent @xmath52 ( see eq.1 ) and the fact that the rough interface cylinder - incline in our experiments is essentially a 1d - system , as well as the probable importance of diffusive processes to explain the emergence of both the gutenberg - richter law and the omori law [ 26 ] , suggest that the picture of sliding activity between ms as a fragmentation dynamics acting in the space of contacts at the interface block - incline could be a good one . a new way to improve the accuracy of the description of irreversible and intermittent failure processes associated with time series of real earthquakes introduces log - periodic corrections to the leading scaling behavior [ 27 ] . inspired in this approach we tried to adjust our experimental time series of slidings with the scaling form @xmath53.\ ] ] in eq.3 , the correction @xmath54 $ ] to the leading scaling behavior @xmath55 of the omori law is essentially the real part of the power law @xmath56 , whose scaling exponent is the complex number @xmath57 , with the imaginary part of @xmath58 corresponding to the angular frequency @xmath59 . novikov in 1969 [ 28 ] pointed out the possibility of log - periodic corrections to explain experimental results on intermittency involving fluids , and nauenberg in 1975 [ 29 ] studied a scaling representation containing a log - periodic dependence in the singular part of the free energy of systems described by scaling operators which exhibit a critical phase transition . in fig.4 , we show in a linear plot the experimental data of fig.1 adjusted with the four parameter expression given in ( 3 ) , with @xmath60 , @xmath61 , @xmath62 , and @xmath63 . all time series of slidings studied in this work are equally quite well described by eq.3 with similar fitting parameters ; in particular , the typical variation in the exponent @xmath41 is @xmath64 ; @xmath65 varies in the interval @xmath66 to @xmath67 ; @xmath68 , and @xmath69 . real sequences of earthquakes [ 27 ] and time series of stock exchange indexes [ 30 ] present commonly angular frequency @xmath59 ( exponent @xmath41 ) in the intervals @xmath70 ( @xmath71 ) , and @xmath72 ( @xmath73 ) , respectively . the time series examined here include a large number of events comparatively to the time series of earthquakes studied in ref.27 . we believe that eq.3 represents a true log - periodic correction to the omori scaling in our time series of slidings and not a spurious log - periodicity generated by limitations in the sampling procedure [ 31 ] . finally , we would like to point out that recently , lima et al [ 32 ] using a simple model in which the coefficient of friction is a random function of the position , obtained the same static exponent found for the experimental size distribution of slidings of ref.1 . however , the average sliding length in ref.32 scales as @xmath74 , while the experimental result is @xmath75 , with @xmath76 [ 1 ] . in view of the results reported in the present work , it would be highly interesting to verify if the model of ref.32 can reproduce the dynamic scaling with log - periodic oscillations given in eq.3 , as well as to compare the behavior of this model with sequences of real earthquakes . we have shown from experiments that sequences of slidings of a solid block on a rough incline submitted to small controlled perturbations have a complex time structure , corroborating recent experimental results reported in [ 3 ] . this situation could have an analogous counterpart in seismology since most models of earthquakes reproduce easily the spatial behavior of this phenomenon which is associated with the gutenberg - richter law [ 17 ] , but not the omori law for aftershocks [ 17,19,26 ] . in this work , we have reported results that indicate that sequences of slidings between mainslidings as well as sequences of slidings after(before ) a mainsliding obey the omori scaling law with an anomalous and robust exponent provided the angle which the incline forms with the horizontal is not too large . in this situation the time series of slidings necessarily presents intermittency [ 3 ] . if , on the contrary , the inclination increases , the anomalous omori scaling disappears together with the intermittent behavior . log - periodic correction to this anomalous omori scaling seems important to a full description of the time behavior of these sequences of slidings .

long sequences of slidings of solid blocks on an inclined rough surface submitted to small controlled perturbations are examined and scaling relations are found for the time distribution of slidings between pairs of large events as well as after and before the largest events . these scaling laws are similar to the omori law in seismology but the scaling exponents observed are different . log - periodicity correction to the omori scaling is also found . it is shown that the scaling behaviors are dependent on the angle that the incline forms with the horizontal . inclined rough surface , omori law , slidings , time scaling 05.40.-a , 05.65.+b , 05.90.+m , 68.35.-p

in 2004 , pro - aim ( program for improvement of death cause information in so paulo , abbreviated from the portuguese name ) was initiated in the so paulo metropolitan area to provide better reporting of causes of death . leptospirosis is a major infectious disease in so paulo , and we started active surveillance for cases of acute renal failure and jaundice , pulmonary hemorrhage , or a combination of both . detailed questionnaires on clinical and epidemiologic features were completed , and necropsies were performed to improve identification of fatal leptospirosis cases in so paulo . death certificates with any clinical features suggestive of leptospirosis or isolated sphs are referred to the municipal health secretariat of so paulo . confirmation protocols include laboratory analysis , clinical and epidemiologic assessment , and verification by necropsy of case - patients who had pathologic features characteristic of leptospirosis in lungs , kidneys , and liver . if fatal leptospirosis is confirmed within 72 hours , public health authorities can be alerted . in a setting of high leptospirosis transmission furthermore , the brazilian experience , as well as that of other countries ( 1 ) , includes a high rate of misdiagnosis of leptospirosis and other clinically indistinguishable acute febrile illnesses such as dengue or scrub typhus fever . thus , rapid identification and confirmation of fatal leptospirosis are important tools for surveillance , public health interventions , and alerting clinicians . we describe our initial experience of actively seeking , identifying , and reporting fatal cases of leptospirosis . using data from january 1 , 2004 , through august 31 , 2006 , we used a cross - sectional approach to analyze death certificate data from the so paulo metropolitan area . fatal cases were confirmed in the laboratory by serologic or immunohistochemical examination , supplemented by epidemiologic and clinicopathologic evidence . pathologic criteria were an important adjunct to confirm cases because 30% of deaths of patients hospitalized for leptospirosis occur within 24 hours , which may preclude serologic diagnosis because of delayed antibody responses . in fulminant infection , histopathologic findings confirm involvement of typical targeted organs such as acute tubular necrosis or interstitial nephritis , acute loss of cohesion of hepatocytes , and pulmonary hemorrhage , which is important because , in leptospirosis - endemic regions , potential leptospirosis patients may have had previous infection and thus preexisting antileptospiral antibodies ( 8) . we emphasize , however , that pathologic criteria are only confirmatory if clinical and epidemiologic criteria for infection are fulfilled . in the experience reported here , 5 cases ( which were included in the laboratory confirmation group ) were confirmed by immunohistochemical examination . leptospiral antigen detection in postmortem samples is important for confirming the diagnosis ( 9 ) but is limited by tissue deterioration if there is a prolonged period between death and necropsy . in 2004 , 42 ( 15% ) of 285 cases of reported leptospirosis cases were fatal ; in 2005 , 28 ( 11% ) of 262 cases were fatal ; and from january 1 through june 2006 , 31 ( 19% ) of 167 cases were fatal . of 101 fatal cases , 62 were confirmed by a combination of serologic and immunohistochemical testing ; 15 cases were suggested on the basis of clinical , pathologic , and epidemiologic findings ; and 24 were suspected on the basis of strong circumstantial clinical and epidemiologic evidence . isolation of leptospires in culture from clinical specimens is the standard for diagnosis but faces logistical obstacles in real - world settings . in our study , only 6 blood samples were collected for culture , and they were uninterpretable because of contamination . although not definitive for identifying infecting leptospiral serovars , microscopic agglutination test titers suggested that the most frequently reacting serogroups in so paulo are icterohemorrhagiae ( 72% ) and autumnalis ( 14% ) . of the 101 fatal cases , fifteen fatal cases were suggested by a combination of necropsy findings plus clinical and epidemiologic evidence . of all fatal cases confirmed by necropsy , weil syndrome with concomitant pulmonary hemorrhage was documented in 86% of cases in 2004 , in 67% in 2005 , and in 69% in 2006 . less common manifestations included weil syndrome without pulmonary hemorrhage , and isolated pulmonary hemorrhage ( table ) . the frequency of clinical manifestations of severe pulmonary disease ( with or without hemorrhages ) was 76% among fatal cases and 26% among nonfatal cases . importantly , 46% of all patients with severe pulmonary symptoms died , a finding that is consistent with the literature ( 1,8 ) . the system of active death notification we describe can be an important tool to evaluate the emerging complications of leptospirosis and the global extent of disease due to leptospirosis . nonetheless , this , as well as any system of active death certification notification , has several limitations . a major problem is increasing the number of necropsies , which may be limited by logistics or cultural norms . increasing the necropsy rate can be aided by prompt response through the death certificate notification system and involvement of public health authorities . another problem is the lack of serologic and cultural confirmation . molecular diagnosis would be ideal and could readily be introduced into this system . the incidence of sphs seems to have changed elsewhere , e.g. , in salvador , another urban area of brazil , where the copenhageni serovar predominates . pulmonary hemorrhage seems to have newly emerged since the year 2000 ( a. i. ko , pers . comm . ) . an active surveillance , death certificate based reporting system represents an important tool that should provide further insights into the natural history and changing clinical manifestations of leptospirosis infection in diverse geographic regions in which the disease is endemic and epidemic . systematic reporting focused on the most severe cases of leptospirosis has the potential for providing a data - driven basis for ministry - level policy development , institution of public health control measures , and quantitative assessment of the global severity of leptospirosis .

severe leptospirosis with pulmonary hemorrhage is emerging globally . measures to control leptospirosis through sanitation depend on accurate case finding and reporting . rapid death certificate reporting , plus necropsy of persons who died of leptospirosis , facilitates public health intervention and could provide an important tool in assessing the global burden of leptospirosis .

penetrating cerebral injuries caused by foreign bodies other than bullets are relatively rare due to the substantial mechanical protection provided by the skull . in clinical practice , several descriptions of foreign bodies such as wood pencils or metal penetrating the cranium have appeared in the literature5,6 ) . however , suicide attempts and self - inflicted nail gun injuries are rarely reported . a good neurological outcome can be expected if the free ends of the nails can be seen in the operative field and if the brainstem and major vessels are spared12 ) . here we report on a difficult case of deep - seated intracranial nail gun injury in which the free end of the nail was not seen . a 43-year - old man was referred to the emergency room due to altered mental status subsequent to a self - inflicted nail gun wound . during a quarrel with a co - worker , he attempted suicide by shooting himself with a nailing gun at his workplace . on physical examination , he was found to have an open laceration about 21 cm in the left parietal region . on neurological examination , he was found to be drowsy with a glasgow coma scale of 14 ( e4 v4 m4 ) . plain skull radiographs revealed a 5-cm , linear , nail - shaped foreign body piercing the brain ( fig . 1 ) . a computed tomography ( ct ) scan of the brain showed the presence of a metallic foreign body in the left parietal lobe . it reached almost to the pons , and multiple fracture fragments were also seen impacted into the parietal lobe ( fig . 2 ) . treatment with a combination of ceftriaxone , chloramphenicol , and metronidazole was initiated and tetanus immunization was administered . the patient was operated immediately and a local scalp incision was made at the nail entry site . after a small circumferential craniectomy , the nail was cautiously removed under intraoperative c - arm guidance to prevent further vascular insult or neurological aggravation ( fig . 3 ) . after washing the wound with antibiotics , it was closed in layers over a drain . the postoperative period was uneventful and the patient exhibited no further neurological aggravation , evidence of infection , or symptoms of raised intracranial pressure . however , in spite of aggressive rehabilitative treatment for 3 months , his right side hemiparesis was not improved and he could not ambulate by himself . although gunshot injury is rare in korea due to gun control , penetrating cranial injuries still occur , mostly from shotguns10 ) . . a few cases of deliberate , self - inflicted , penetrating brain injury from nail guns have been reported12,13 ) . in most of these cases , patients survive with a good neurological outcome if the brainstem and major cerebral vessels have been spared and the offending nail is seen during physical examination . however , in our case , the free end of the nail was not seen and only the penetration site could be observed . as a result neuroimaging is vital for surgical decision - making in any penetrating head injury , offering guidance as to the best surgical approach , the size and site of the craniotomy , and the route of extraction of the foreign body , as well as informing the decision to choose non - surgical management . simple radiographs are helpful for intracranial localization of metallic foreign bodies1,2,5 ) . in the case of non - metallic bodies , cranium defects or the foreign body itself can occasionally be seen14 ) . ct scanning of the brain is now the primary modality used in the neuroradiologic evaluation of patients with penetrating head injury . this is because ct scanning is quick and provides improved identification of in - driven bone and missile fragments , characterization of the missile trajectory , evaluation of the extent of brain injury , and detection of intracranial hematomas and mass effects11 ) . in contrast the strength of the magnetic field poses a danger when any ferromagnetic metals are present as foreign bodies . for the same reason , we could not use a three - dimensional navigation system in our patient . it is recommended that documenting vascular damage should be performed using cerebral angiography when the foreign body is located just beneath the major arterial or venous systems1 ) . in spite of the development of antibiotics , infectious complications are frequently seen in the penetrating head wound patients . prompt surgical exploration is mandatory to reduce the mortality and complication rate . despite antibiotic treatment , the morbidity rate is 33% in cases receiving prompt surgical treatment and rises to 53% in cases where surgery is delayed9 ) . small sized foreign bodies located deep in the brain can be left in place7,10,12 ) . if the foreign body is not in close proximity to major arteries or veins and has extracranial components , a blind removal without craniotomy can be performed . surgery should be performed for removal of a contaminated foreign body , repair of vascular or dural damage , or drainage of intracranial masses6,7 ) . removed foreign bodies should be cultured for aerobic , anaerobic , or fungal pathogens . in our case , complications of attempts to treat this kind of injury include meningitis , cerebral abscess , hematomas , cerebral aneurysm , hydrocephalus , and focal neurological deficits7 ) . this case demonstrates that a nail gun is a potentially dangerous tool capable of causing a penetrating brain injury . emergency surgical removal should be performed to save the patient 's life even in cases of deep penetrating injuries caused by a nail gun .

penetrating cerebral injuries caused by foreign bodies occur rarely due to the substantial mechanical protection offered by the skull . throughout most of history , the brain , residing in a " closed box " of bone , has not been vulnerable to external aggression . recently , we encountered a serious penetrating craniocerebral injury caused by a nail gun . total excision of the offending nail via emergency craniotomy was performed , but the patient 's neurologic status was not improved in spite of aggressive rehabilitative treatment . here , we report on this troublesome case in light of a review of the relevant literature .

SECTION 1. MEDICARE DEMONSTRATION PROGRAM ON THE USE OF THIRD-PARTY INTEREST-FREE PAYMENT ARRANGEMENTS TO REDUCE MEDICARE HOSPITAL PART A BAD DEBT CLAIMS. (a) In General.--The Secretary of Health and Human Services (in this section referred to as the ``Secretary'') shall establish a 3-year demonstration program (in this section referred to as the ``demonstration program'') in 5 States to determine the impact on patient engagement and satisfaction, health outcomes, and claims for Medicare hospital part A bad debt (as defined in subsection (d)(2)) of hospitals' implementing third-party interest-free payment arrangements (as defined in subsection (b)). (b) Third-Party Interest-Free Payment Arrangement Defined.--In this section, the term ``third-party interest-free payment arrangement'' means, with respect to a hospital and individuals who are receiving inpatient hospital services for which payment may be made under part A of title XVIII of the Social Security Act, an arrangement between the hospital, a third-party, and such individuals under which-- (1) the hospital offers to all such individuals the option of making payment of Medicare part A cost-sharing under such an arrangement for such services rather than through the routine billing process for such cost-sharing; (2) in the case of any such individual who agrees to such offer, the hospital assigns to the third party the rights of collection for such Medicare part A cost-sharing from such individual and efforts for such collection by the third party pursuant to this section shall be treated as reasonable collection efforts by the hospital for purposes of section 413.89(e) of title 42 of the Code of Federal Regulations (or any successor regulation); (3) in the case of any such individual who does not agree to such offer, the hospital payment of Medicare part A cost- sharing for such services shall continue to be made through the routine billing process for such cost-sharing (including with respect to claims for Medicare hospital part A bad debt); and (4) the third party-- (A) participates in a level of financial engagement and education with all such individuals who agree to such offer to ensure such individuals are able to afford such cost-sharing payments; (B) in collecting the amounts so owed, permits all such individuals who agree to such offer to make payment over time through a payment plan that does not charge interest with respect to the balance of the amount so owed; and (C) pays the hospital the amount so collected under the arrangement less a fee that does not exceed 15 percent of the amount so collected. (c) Payment Incentive.--The demonstration program shall provide that a hospital that participates in such a third-party interest free payment arrangement under the program and demonstrates improved patient engagement and satisfaction, improved health outcomes, and a reduction in the number of claims for Medicare hospital part A bad debt that are reported to the Secretary is paid an amount equal to 10 percent of the original amount owed in Medicare part A cost-sharing that is collected under the arrangement. Such amount shall be paid from funds appropriated (under subsection (f)(1) of section 1115A of the Social Security Act (42 U.S.C. 1315a)) for activities to carry out such section. (d) Report to Congress.--After the completion of the demonstration program, the Secretary shall submit a report on the demonstration program to the Committee on Ways and Means of the House of Representatives and the Committee on Finance of the Senate. The report shall include an analysis of whether the demonstration program reduced the number and amount of Medicare hospital part A bad debt claims and if there were improved health outcomes for Medicare beneficiaries who did not forgo medical care due to their inability to pay for Medicare part A cost-sharing. (e) Other Definitions.--In this section: (1) Medicare part a cost-sharing.--The term ``Medicare part A cost-sharing'' means, with respect to a hospital, amounts owed to the hospital that are derived from deductibles and coinsurance imposed under part A of title XVIII of the Social Security Act (42 U.S.C. 1395c et seq.). (2) Medicare hospital part a bad debt.--The term ``Medicare hospital part A bad debt'' means bad debt of a hospital that is attributable to the inability of the hospital to collect Medicare part A cost-sharing, taking into account collections made under third-party interest-free payment arrangements made under the demonstration program.

This bill requires the Centers for Medicare &amp; Medicaid Services (CMS) to establish a three-year demonstration program to determine the impact of third-party, interest-free payment arrangements on: (1)&nbsp;health outcomes, (2)&nbsp;patient engagement and satisfaction, and (3) claims for bad debt that are attributable to a hospital's inability to collect&nbsp;deductibles and coinsurance&nbsp;for Medicare hospital services.&nbsp;Under the program, the CMS&nbsp;shall&nbsp;provide a payment incentive to a hospital that participates in such a payment&nbsp;arrangement and demonstrates improvement in those three areas.

Russian newspaper says it has evidence that at least three men have been killed in ‘prophylactic sweep’ in Chechnya Authorities in the Russian republic of Chechnya have launched an anti-gay campaign that has led to authorities rounding up dozens of men suspected of being homosexual, according to the Russian newspaper Novaya Gazeta and human rights activists. The newspaper’s report, by an author regarded as a leading authority on Chechnya, claimed that more than 100 people had been detained and three men killed in the roundup. It claimed that among those detained were well-known local television personalities and religious figures. Alvi Karimov, spokesperson for Chechnya’s leader, Ramzan Kadyrov, described the report as “absolute lies and disinformation”, basing his denial on the claim that there were no gay people in Chechnya. “You cannot detain and persecute people who simply do not exist in the republic,” he told Interfax news agency. “If there were such people in Chechnya, the law-enforcement organs wouldn’t need to have anything to do with them because their relatives would send them somewhere from which there is no returning.” A spokesman for the region’s interior ministry told the Russian newspaper RBC that the report was “an April fool’s joke”. However, Ekaterina Sokirianskaia, Russia project director for the International Crisis Group, told the Guardian she had been receiving worrying information about the issue from various sources over the past 10 days. “I have heard about it happening in Grozny [the Chechen capital], outside Grozny, and among people of very different ages and professions,” she said. The extreme taboo nature of the subject meant that much of the information was arriving second or third hand, and as yet there are no fully verifiable cases, she added. “It’s next to impossible to get information from the victims or their families, but the number of signals I’m receiving from different people makes it hard not to believe detentions and violence are indeed happening.” Chechnya is formally part of Russia, but functions as a quasi-independent state in which the word of Kadyrov often seems to transcend Russian laws. He has overseen the rebuilding of the republic with Moscow’s money, after two devastating wars. Kadyrov has at various times endorsed polygamy, compulsory wearing of the hijab for women in public places, and collective punishment for the relatives of those involved in the Islamist underground. Chechen society is strictly conservative, meaning that unlike other cases where relatives or rights activists may put pressure on authorities when a homosexual relative disappears, those suspected are likely to be disowned by their own families. Locals say that if a family was known to have a gay member, other relatives would find it difficult to marry due to the “shame”. Attitudes to LGBT rights are mixed in Russia, with an infamous law banning the “propaganda of homosexuality among minors” on the books. But Moscow and other big cities have a thriving gay scene, even if much of it remains underground. In Chechnya and the other Muslim republics of the North Caucasus, there is no discussion of the issue, and gay men do not even tell their closest friends of their orientation. The Novaya Gazeta article claimed that three people had been killed, and suggested others could have been handed to their families with the expectation that the family would perform an honour killing. An LGBT rights organisation in St Petersburg has set up an anonymous hotline for gay people in Chechnya to seek help with evacuation from the republic. After years of threats and repression, almost no independent journalists or rights activists are able to work in the region, and those who do work on human rights in the republic dismissed the newspaper report. “I haven’t had a single request on this issue, but if I did, I wouldn’t even consider it,” Kheda Saratova, a Chechen activist who is on Kadyrov’s human rights council, told a Russian radio station. “In our Chechen society, any person who respects our traditions and culture will hunt down this kind of person without any help from authorities, and do everything to make sure that this kind of person does not exist in our society.” ||||| MOSCOW (AP) — A respected Russian newspaper says it has uncovered information that police in the southern Russian republic of Chechnya have rounded up more than 100 men suspected of homosexuality and that at least three have been killed. The Saturday report in Novaya Gazeta said it had confirmed the information with sources in the Chechen police and government, but gave no details. The report was denied by Chechen President Ramzan Kadyrov's spokesman, who suggested there are no homosexuals in the Muslim-majority region. Ali Karimov said, according to the state news agency RIA Novosti, "it's impossible to persecute those who are not in the republic." The Kremlin-backed Kadyrov is widely accused of extensive human rights violations. He has brought Islam to the fore of Chechnya's daily life, including opening what is called Europe's biggest mosque.

– A respected Russian newspaper says it has uncovered information that police in the southern Russian republic of Chechnya have rounded up more than 100 men suspected of homosexuality and that at least three have been killed. The Saturday report in Novaya Gazeta said it had confirmed the information with sources in the Chechen police and government, but gave no details, reports the AP. "In Chechnya, the command was given for a 'prophylactic sweep' and it went as far as real murders," read the report. Adds an activist with the International Crisis Group, "It came from too many sources not to be true." The report was denied by Chechen President Ramzan Kadyrov's spokesman, who suggested there are no homosexuals in the Muslim-majority region. Ali Karimov said, according to the state news agency RIA Novosti, "it's impossible to persecute those who are not in the republic." Further, per the Guardian, "If such people existed in Chechnya, law enforcement would not have to worry about them, as their own relatives would have sent them to where they could never return." The Kremlin-backed Kadyrov is widely accused of extensive human rights violations. He has brought Islam to the fore of Chechnya's daily life, including opening what is called Europe's biggest mosque.

there is as yet no clear , coherent and complete explanation for the origins of elliptical galaxies and their gas contents . since the early numerical simulations of toomre & toomre ( 1972 ) it has been evident that mergers between spirals can produce objects whose structure resembles that of an elliptical galaxy ( e.g. barnes & hernquist 1992 ; naab & burkert 2003 ) . a current view is that bright ellipticals come from early , major mergers between disks ( c.f . naab et al . 1999 ; naab & burkert 2003 ) . minor mergers - those involving mass ratios of roughly 3:1 and larger - probably formed the fainter galaxies , those with disk components and large rotational speeds . in all cases some dissipation appears to be needed ( e.g. barnes & hernquist 1996 ; shioya & bekki 1998 ; cretton et al . 2001 ; robertson et al . 2006 ; naab , jessiet & burkert 2006 ) , especially for making fainter galaxies , but how much is not clear . to further complicate the situation , it is becoming clear that mergers between gas - poor objects have contributed importantly to the growth of many luminous ellipticals ( van dokkum 2005 , naab et al . 2006 ; bell et al . 2006 ; boylan - kolchin et al . 2006 ) - the so - called dry or red merger hypothesis . on the other hand , the classical monolithic formation idea has refused to die ; a modified version suggested by kormendy ( 1989 ) and kobayashi ( 2004 ) is still attractive for explaining radial gradients in absorption line strengths ( ogando et al 2005 ) . there is not yet even clear agreement on the observed properties of ellipticals , especially the properties of their interstellar media . for example , lees et al . ( 1991 ) and knapp & rupen ( 1996 ) found molecular gas in about half of the iras - selected galaxies they observed , while georgakakis et al . ( 2001 ) reported co in just 25 percent ( hi in almost 50 percent ) . wiklind et al . ( 1995 ) found co emission from 55 percent . the georgakakis et al . work , however , was based on a sample of interacting galaxies at different stages of evolution ( the stage was determined by the optical colours according to the prescription given in georgakakis et al . 2000 ) , while the other three studies used an iras criterion the 100 micron flux @xmath2 had to be @xmath3 jy . wiklind et al . ( 1995 ) carefully assessed the morphology of each galaxy in their sample , and when they removed the merger candidates the detection rate ( of presumably normal ellipticals ) dropped to about 40 percent . what is clear , and has been since faber & gallagher ( 1976 ) , is that gas from evolved stars _ must _ be returned to the interstellar medium of a galaxy , where after a hubble time it will ( if not recycled back into stars or ejected in galactic winds ) account for up to @xmath410 percent of the visible mass ( i.e. ciotti et al . 1991 , kennicutt et al . 1994 , brighenti & mathews 1997 ) . it is also clear that new gas can be acquired by merging with like - sized galaxies , absorbing dwarf companions , or accreting pristine material from the nearby intergalactic medium . simple physical arguments show that the mixing of returned gas within a galaxy dominated by random motions will heat that gas to temperatures of @xmath5 k , which explains why ellipticals with @xmath6 l@xmath7 have hot x - ray emitting halos ( osullivan , forbes & ponman 2001 ) . continuing energy input from aging stars ( supernovae , novae and winds from very massive stars ) keeps at least a portion of that gas hot , and may even blow it out of the galaxy . the details of energy transfer to the ism , though , are complex and the general outcome correspondingly uncertain ( c.f . mathews 1990 ) . simulations show that significant amounts of gas can cool near the centers ( e.g. brighenti & mathews 1997 ; pellegrini & ciotti 1998 ) . efforts to follow the evolution of the hot ism in elliptical galaxies have led to the strong prediction that only massive galaxies will develop central reservoirs of cool gas . it is an ongoing puzzle , therefore , that observers have reported higher hi and co detection rates among less luminous galaxies ( lake & schommer 1984 , lees et al . 1991 for hi and co , respectively ) . lees et al . point to a possible bias against detecting broad , faint emission lines in massive objects . another possibility is that ism reheating by a central agn is more effective in massive galaxies ; for example , di matteo et al . ( 2005 ) found in simulations that when the mass of the central black hole exceeds @xmath8 m@xmath7 that the outflows generated can turn off star formation . a variety of mechanisms , such as ram pressure stripping , galaxy - galaxy interactions , and perhaps thermal interactions with the hot gas or sputtering and grain destruction , affect the ism of galaxies moving within a cluster ; field galaxies should be free of such complications , and are therefore the obvious starting points for understanding internal processes governing ism evolution . published studies , though , have been biased not only towards cluster membership but also in favor of objects likely to contain a detectable ism ( e.g. far - infrared detection , optical dust features ) . following the philosophy of our recent study of s0 galaxies ( welch & sage 2003 ) , we have defined a volume - limited sample of non - cluster elliptical galaxies with the aim to determine systematically their cool gas contents . we used integration times designed to reveal ( at the 5@xmath9 level ) just one percent of the mass expected to be returned by stellar evolution ( ciotti et al . 1991 ) , so that even non - detections give us physically meaningful constraints . we also take advantage of increased bandwidth compared to earlier surveys , which facilitates detection of rotationally broadened lines . this paper reports our first results : co observations of 18 , of which we have detected emission ( in either the 2 - 1 or 1 - 0 lines ) from six . we used the nearby galaxies catalog ( tully 1988 ) to define a volume - limited sample of galaxies with distance @xmath10 mpc , and declination @xmath11 excluding members of the virgo and fornax clusters . we added from the rc3 ( de vaucouleurs et al . 1991 ) any ellipticals satisfying the same distance and declination criteria that were not in the nearby galaxies catalog , arriving at a final list of 46 galaxies . some galaxies classified as elliptical ( type -5 ) in the nearby galaxies catalog are assigned type s0 in the rc3 ( table 1 ) . the present sample , then , is chosen with basically the same criteria as in our recent work on lenticulars ( welch & sage 2003 ; sage & welch 2006 ) with one exception : in the s0 study we excluded cases where interaction was obvious on the palomar sky survey prints and in the present case we have retained them . the galaxies thereby retained are ngc 3226 , ngc 3640 , and ngc 7464 ; we have not yet observed these objects . the entire sample is listed in table 1 . all positions and systemic velocities are from the nasa extragalactic database . the data were obtained through pooled ( service ) observations ( 27 october 2004 to 8 november 2004 ) and during a run from 10 may 2005 to 13 may 2005 ( ljs and gaw present ) , at the iram 30 m telescope in spain . all data reduction was done using class . the observed galaxies , along with co integrated line intensities , uncertainties and line windows , are listed in table 2 . the data were co - added and reduced in the normal way , with a few obviously bad scans omitted . the only exception was maffei 1 , which is both large and affected by local ( milky way ) emission . we observed 5 points in maffei 1 the center and @xmath12 away on either side of both the major and minor axes . using the data from the survey of milky way emission ( heyer et al . 1998 ) we identified the contamination at all positions and removed it . no residual emission was evident in any of the scans , so we co - added all positions . there was still no evidence for any emission . of the galaxies observed , we detected ( at the @xmath13 level ) six in the 1 - 0 line , and three in the 2 - 1 line . there were no 2 - 1 data for maffei 1 and ngc 7468 because a cable was unplugged during the service observing . unlike our survey of lenticulars , the detection rate is rather low even though integration times were designed to detect as little as 1% of the expected gas mass . furthermore , the 2 - 1 line is much more difficult to see . there were several cases in the lenticular study where only the 2 - 1 line was seen , from which we concluded that the gas was very centrally concentrated ( welch & sage 2006 ) . for the elliptical galaxies the reverse seems to be true the gas does not seem to be particularly concentrated , based upon the limited line information , or it is much colder than in lenticulars . the reasoning goes as follows if the gas is spread over a region the size of the 1 - 0 beam ( or larger ) , and not unusually warm , then the 1 - 0 line will appear stronger than the 2 - 1 , simply because more molecules are contributing to the emission . the lack of concentration is evident in interferometric maps ( young 2002 , 2005 ) , where of the seven galaxies studied the co only one had a co - emitting region smaller than the 1 - 0 beam at the 30 m telescope . elliptical galaxies are known to be generally more difficult to detect in co emission than s0s ( e.g. lees et al . 1991 ) . we find co in 78 percent of our volume - limited s0 sample but in only 33 percent of the present , preliminary elliptical sample . the two samples span similar ranges of luminosity and local galaxy density . on the other hand , our observations so far have been weighted towards the more massive galaxies ( we have observed 58 percent of targets brighter than m(b ) = -20 but only 32 percent of the fainter ones ) , while it is known that less massive ellipticals are more likely to contain gas ( i.e. lake & schommer 1984 , lees et al . 1991 ) table 3 contains the 2 - 1/1 - 0 line ratios for the three galaxies for which we have @xmath14 detections in both lines . the number is too small , and the scatter too large , for us to be able to conclude anything from those ratios . we have found published co observations for 6 galaxies listed in table 2 : ngc 720 and ngc 4636 ( braine et al . 1997 ) , ngc 2768 and ngc 7468 ( wiklind et al . 1995 ) , ngc 4697 ( knapp & rupen 1996 ) , and ngc 4742 ( lees et al . our results are in reasonably good agreement , although we typically report somewhat lower integrated intensities or more sensitive upper limits . the striking difference in co detection rates between ellipticals and lenticulars may offer important guidance for future investigations of ism evolution in early type galaxies . we have speculated ( sage & welch 2006 ) that the co emission from s0 galaxies comes mainly from gas which has cooled out of the hot , x - ray phase - i.e. gas returned by the stars . it is not yet evident that the same is true in elliptical galaxies ( one of our goals is to address this issue with more data ) . monolithic models of ism evolution in early type galaxies incorporate a variety of factors which influence whether , and how much , gas cools from the hot phase ( e.g. mathews 1990 , ciotti et al . 1991 , brighenti and mathews 1997 , pellegrini & ciotti 1998 ) ; those include the mass of the dark halo , the effectiveness of ( type ia ) supernova heating , and agn feedback . more massive dark matter halos promote the cooling of gas near the center by inhibiting the development of a galactic wind ; since more hot gas is retained globally though , the x - ray luminosities are also higher . models with high l(x ) might therefore also develop central clouds of atomic and/or molecular gas ( but those models - e.g. ciotti et al . 1991 - do not follow the detailed evolution of the cold ism ) . in general , ellipticals are found to have higher x - ray luminosities and larger l(x)/l(b ) than lenticulars ( eskridge et al . 1995a , b ) , consistent with them being more dark matter dominated . if the cold gas in both galaxy types primarily originates in cooling from a hot phase , one might therefore expect higher co detection rates in our elliptical sample , which is contrary to what we find . we caution , though , that our samples of e and s0 galaxies include relatively fewer high luminosity objects than the einstein sample ( with correspondingly low x - ray detection rates ) , and may therefore not reflect the trends found by eskridge et al . on the other hand , braine et al . ( 1997 ) found no co emission from a sample of six luminous ellipticals . agn feedback is currently thought theoretically to be important in suppressing cooling flows in both clusters and individual elliptical galaxies ( di mateo et al . 2005 ; sazonov et al . 2005 ) , and observational evidence supporting that view has recently been reported ( schawinski et al . although the process is complex and only partly understood ( cf brighenti & mathews 2002 , 2003 ) , the current picture of agn energy production ( binney & tabor 1995 ; ciotti & ostriker 1997 , and more recently brighenti & mathews 2006 ) suggests that feedback is likely to occur , at least initially , along the spin axis of the central supermassive black hole . since that axis would not often point towards the disk of a lenticular host galaxy , cooling gas from its disk stars might often escape being reheated , which might lead to the observed higher detection frequency in s0s . in other words , agn reheating might be more effective in a pure spheroid simply because gas return is more isotropic than in a disk galaxy . published simulations , however , have not yet featured directed agn feedback within disks , so that explanation remains speculative . sazonov et al . ( 2005 ) did show that when the mass of gas drops below one percent of the mass of stars in the central region , radiative heating by the agn overwhelms cooling , and much of the remaining gas will be expelled . the flattened shapes of lenticulars are expected to make it easier for supernovae to heat and eject returned gas ( c.f . dercole & ciotti 1998 ) . while that might help explain the generally lower x - ray luminosities among s0 galaxies , it would also seem to predict lower , not higher , co detection rates among s0s , contrary to the observations . in the hierarchical formation picture lenticular and elliptical galaxies are products of different merging histories . we have already commented on our current , blurry picture of elliptical galaxy formation . even less obvious is the way to make lenticular galaxies in low - density environments ( stocke et al . 2004 ) , although it seems that most s0s can not simply be former spirals ( burstein et al . furthermore , it remains to work out how differing assembly sequences for es and s0s can account for differences in cold gas detection rates , in the distribution of the molecular and atomic phases , and possibly also in the global values of m(h@xmath0)/m(hi ) ( see below ) ; presently there is much room for speculation . for example , perhaps ellipticals typically form in somewhat dryer mergers than lenticulars , as larger gas contents do seem to produce diskier remnants . barnes ( 2002 ) showed that , depending on merger geometry , some tens of percent of the gas carried into a major merger could end up in a large - scale gas disk that could later form a stellar disk . naab , jesseit & burkert ( 2006 ) also showed that the presence of even small amounts of gas in a merger tends to make the remnant more axisymmetric , more dominated by minor axis tube orbits , and less boxy ( and so more like a lenticular galaxy ) . on the other hand , perhaps timing is important , in that ellipticals usually acquired their gas earlier than s0s , and have had more time to dispose of it by feeding an agn and/or making stars . previous surveys have reported higher cool gas detection rates among low luminosity e and s0 galaxies ( lake & schommer 1984 , and lees et al . 1991 for hi and co , respectively ) ; our results show a similar trend , albeit from small numbers . we find co in only 1 of 7 galaxies ( or 14 percent ) brighter than m(b ) = -20 , but in 5 of 11 ( 45 percent ) of fainter galaxies . for a cut at m(b ) = -19 the results are 20 percent and 50 percent , respectively . the lower co content in the more massive galaxies may arise because the high - luminosity galaxies are more likely formed in dry mergers ( bell et al . 2006 ; boylan - kolchin et al . 2006 ) , or perhaps the evolution of the gas is dominated by agn feedback ( sazonov et al . 2005 ) . in contrast , other published simulations of ism evolution inside isolated galaxies ( e.g. ciotti et al . 1991 ; pellegrini & ciotti 1998 ) suggest that cool gas more readily accumulates in brighter , not fainter , ellipticals . in summary , the detection rates of molecular gas among early type galaxies are not easy to understand from their other properties , and useful predictions are not available from either of the two competing paradigms of galaxy formation . much more work is needed to bring a consensus into view . one of the most puzzling and , we believe , potentially most significant discoveries from our survey of s0 galaxies has been the existence of a cutoff in the amount of cool gas present ( sage & welch 2006 ) . regardless of luminosity , the most gas - rich lenticulars have @xmath410 percent of the amount returned by their stars after the first 0.5 gyr . table 4 presents the h@xmath0 and hi masses for ellipticals from the present work and the literature , respectively . although we have both co and hi data for less than half of the elliptical sample ( lack of co observations is the main deficiency ) there is already an indication that the same cutoff may be present ( figure 2 ) ; the outstanding exception is ngc 7468 ( markarian 314 ) , which has almost as much gas as predicted by ciotti et al . ( 1991 ) - most of this is hi . although isolated , its optical structure is clearly peculiar . perhaps ngc 7468 has recently acquired additional atomic gas from nearby . the cool gas in ellipticals and s0s may have another common attribute : galaxies with the most gas also have relatively more in the atomic phase . the correlation , shown in figure 3 , is merely suggestive due to the paucity of observations ; the reader should compare with the analogous plot for s0 galaxies in figure 13 in sage & welch ( 2006 ) . an interesting difference between the two plots is their relative offset in m(h@xmath0)/m(hi ) : elliptical galaxies seem more deficient in molecular gas by an order of magnitude than s0s , when compared at the same value of m(ism)/m(pre ) . if cooling flows generate most of the observed molecular gas in early - type galaxies , that result would suggest that some mechanism , perhaps agn reheating , moderates them more effectively in ellipticals in summary , we have begun to assess the amount of cool gas within the members of a volume limited sample of elliptical galaxies . co is much more frequently detected in s0s , which we speculate might be because agn feedback is less effective at reheating the gas returned within disks . presently available data indicate that whatever mechanisms operate to impose a cutoff on the cool gas mass in s0 galaxies also operate in ellipticals . a clear but still poorly established trend that more gas rich ellipticals have relatively more atomic gas mimics the more robust trend shown by s0s . we emphasize that additional co observations ( and in some cases hi observations ) are needed to improve the statistics , because of our small sample size . differences in the gas properties of ellipticals and lenticulars may reveal robust new indications of whether their formation mechanisms differed and how their evolution proceeded . we are not yet able to identify the physical causes of the trends we report . more realistic simulations of ism evolution , based on each of the competing paradigms of galaxy evolution - 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garman , l. , scoville , n. , schneider , s. , schloerb , f. p. , lord , s. , lesser , a. , kenney , j. , huang , y .- l . , devereux , n. , claussen , m. , case , j. , carpenter , j. , berry , m. , & allen , l. 1995 , , 98 , 219 . ngc 584 & 01:31:20.7 & -06:52:05 & 1802 & e4 & 23.4 & -20.68 + ngc 596 & 01:31:36.8 & -06:53:37 & 1876 & e+pec(unc ) & 23.8 & -20.22 + ngc 636 & 01:39:06.5 & -07:30:45 & 1860 & e3 & 24.2 & -19.71 + ngc 720 & 01:53:00.5 & -13:44:19 & 1745 & e5 & 20.3 & -20.38 + ngc 821 & 02:08:21.1 & + 10:59:42 & 1735 & e6(doubtful ) & 23.2 & -20.21 + + ngc 855 & 02:14:03.6 & + 27:52:38 & 595 & e & 4.3 & -15.28 + ic 225 & 02:23:53.8 & + 01:09:38 & 1535 & e & 17.0 & -16.72 + maffei 1 & 02:36:35.4 & + 59:39:19 & 13 & ge & 3.6 & -20.50 + ngc 1052 & 02:41:04.8 & -08:15:21 & 1510 & e4 & 17.8 & -19.81 + ngc 1172 & 03:01:36.0 & -14:50:12 & 1669 & e+(unc ) & 18.3 & -18.50 + + ngc 1297 & 03:19:14.2 & -19:06:00 & 1578 & sab0(pec ) & 18.3 & -18.71 + haro 20/ugca 073 & 03:28:14.5 & -17:25:10 . & 1866 & e+(doubtful ) & 21.9 & -16.94 + ngc 1407 & 03:40:11.9 & -18:34:49 & 1779 & e0 & 21.6 & -21.02 + ngc 2768 & 09:11:37.5 & + 60:02:14 & 1373 & e6(unc ) & 23.7 & -21.13 + ngc 3073 & 10:00:52.1 & + 55:37:08 & 1155 & sab0- & 19.3 & -18.03 + + n3115 dw1 & 10:05:41.6 & -07:58:53.4 & 698 & `` de1,n '' & 13.4 & -17.07 + ngc 3156 & 10:12:41.2 & + 03:07:46 & 1318 & s0(unc ) & 18.6 & -18.54 + ngc 3193 & 10:18:24.9 & + 21:53:55 & 1399 & e2 & 23.2 & -20.05 + ngc 3226 & 10:23:27.0 & + 19:53:55 & 1151 & e3 pec(unc ) & 23.4 & -19.57 + ngc 3377 & 10:47:49.6 & + 13:59:08 & 665 & e5 + & 8.1 & -18.55 + + ngc 3379 & 10:47:49.6 & + 12:34:54 & 911 & e1 & 8.1 & -19.39 + ugc 5955 & 10:52:04.2 & + 71:46:23 & 1249 & e & 16.8 & -17.12 + ngc 3522 & 11:06:40.4 & + 20:05:08 & 1221 & e & 20.6 & -17.46 + ic 678 & 11:14:06.4 & + 06:34:37 & 968 & e & 17.6 & -16.48 + ngc 3605 & 11:16:46.6 & + 18:01:02 & 668 & e4 & 16.8 & -18.03 + + ngc 3608 & 11:16:58.9 & + 18:08:55 & 1253 & e2 & 23.4 & -19.94 + ngc 3640 & 11:21:06.8 & + 03:14:05 & 1251 & e3 & 24.2 & -20.78 + ngc 3818 & 11:41:57.3 & -06:09:20 & 1701 & e5 & 24.7 & -19.52 + ngc 4033 & 12:00:34.7 & -17:50:33 & 1617 & e6 & 23.9 & -19.49 + ngc 4125 & 12:08:06.0 & + 65:10:27 & 1356 & e6 pec & 24.2 & -21.35 + + ngc 4239 & 12:17:14.9 & + 16:31:53 & 940 & e & 16.6 & -18.09 + ugc 7354 & 12:19:09.9 & + 03:51:21 & 1526 & e pec(unc ) & 14.6 & -16.52 + ngc 4278 & 12:20:06.8 & + 29:16:51 & 649 & e1 + & 9.7 & -18.82 + ngc 4283 & 12:20:20.8 & + 29:18:39 & 984 & e0 & 9.7 & -17.02 + ngc 4308 & 12:21:56.9 & + 30:04:27 & 589 & e(unc ) & 9.7 & -15.83 + + ngc 4494 & 12:31:24.0 & + 25:46:30 & 1344 & e1 + & 9.7 & -19.23 + ugc 7767 & 12:35:32.4 & + 73:40:29 & 1282 & e & 17.9 & -17.73 + ngc 4648 & 12:41:44.4 & + 74:25:15 & 1414 & e3 & 20.4 & -18.84 + ngc 4627 & 12:41:59.7 & + 32:34:25 & 542 & e4 pec & 13.7 & -17.71 + ngc 4636 & 12:42:49.9 & + 02:41:16 & 938 & e0 + & 17.0 & -20.68 + + ugca 298 & 12:46:55.4 & + 26:33:51 & 801 & e+(unc ) & 8.9 & -15.14 + ngc 4697 & 12:48:35.9 & -05:48:03 & 1241 & e6 & 23.3 & -21.67 + ngc 4742 & 12:51:48.0 & -10:27:17 & 1270 & e4(unc ) & 23.2 & -19.81 + ngc 5845 & 15:06:00.8 & + 01:38:02 & 1450 & e ( unc ) & 21.9 & -18.16 + ngc 7464 & 23:01:53.7 & + 15:58:26 & 1875 & e1 pec(unc ) & 19.2 & -17.39 + + ngc 7468 & 23:02:59.2 & + 16:36:19 & 2081 & e3 pec(unc ) & 23.2 & -18.03 + ngc 636 & 1773 - 1931 & @xmath15 & 0.0051 & @xmath16 & 0.0060 + ngc 720 & 1543 - 1972 & @xmath17 & 0.0054 & @xmath18 & 0.0054 + ic 225 & 1523 - 1594 & @xmath19 & 0.0016 & @xmath20 & 0.0012 + maffei 1 & -99 - 166 & @xmath21 & 0.0022 & & + ngc 1407 & 1478 - 2058 & @xmath22 & 0.0051 & @xmath23 & 0.0055 + + ngc 2768 & 1168 - 1571 & @xmath24 & 0.0035 & @xmath25 & 0.0038 + ngc 3073 & 1093 - 1205 & @xmath26 & 0.0023 & @xmath27 & 0.0023 + ngc 3115 dw1 & 517 - 901 & @xmath28 & 0.0034 & @xmath29 & 0.0025 + ngc 3193 & 1203 - 1602 & @xmath30 & 0.0085 & @xmath31 & 0.011 + ngc 3605 & 425 - 907 & @xmath32 & 0.0046 & @xmath33 & 0.0042 + + ngc 4239 & 768 - 1091 & @xmath34 & 0.0043 & @xmath35 & 0.0050 + ngc 4283 & 871 - 1110 & @xmath36 & 0.0038 & @xmath28 & 0.0047 + ngc 4494 & 1061 - 1541 & @xmath37 & 0.0044 & @xmath38 & 0.0060 + ngc 4648 & 1251 - 1672 & @xmath39 & 0.0038 & @xmath40 & 0.0037 + + ngc 4636 & 794 - 1114 & @xmath41 & 0.0029 & @xmath21 & 0.0020 + ngc 4697 & 1057 - 1482 & @xmath42 & 0.0052 & @xmath43 & 0.0060 + ngc 4742 & 1057 - 1482 & @xmath44 & 0.0027 & @xmath45 & 0.0029 + ngc 7468 & 1966 - 2319 & @xmath46 & 0.0032 & & + lrrc ngc 636 & @xmath50 & @xmath51 & 1 + ngc 720 & @xmath52 & @xmath53 & 1 + ic 225 & @xmath54 & & + maffei 1 & @xmath55 & & + ngc 1407 & @xmath56 & @xmath57 & 1 + + ngc 2768 & @xmath58 & @xmath59 & 2 + ngc 3073 & @xmath60 & @xmath51 & 3 + ngc 3115 dw 1 & @xmath61 & & + ngc 3193 & @xmath62 & @xmath63 & 4 + ngc 3605 & @xmath64 & @xmath65 & 5 + + ngc 4239 & @xmath66 & @xmath67 & 6 + ngc 4283 & @xmath68 & @xmath69 & 1 + ngc 4494 & @xmath70 & @xmath71 & 7 + ngc 4648 & @xmath72 & @xmath73 & 8 + ngc 4636 & @xmath74 & @xmath75 & 9 + + ngc 4697 & @xmath76 & @xmath77 & 10 + ngc 4742 & @xmath78 & @xmath79 & 1 + ngc 7468 & @xmath80 & @xmath81 & 2 + +

we present preliminary results from a survey of co emission from members of a volume - limited sample of non - cluster elliptical galaxies . our intent is to compare the gas properties of these ellipticals to a sample of lenticulars selected using similar criteria . the data , although still sparse , suggest that the cool gas in ellipticals shows the same puzzling upper mass cutoff found in the lenticular galaxies . we find , however , significantly lower detection rates and possibly much lower h@xmath0/hi mass ratios in the ellipticals . the detection rate is higher among the lower - mass galaxies , as has been found previously . this seems puzzling given that the deeper potential wells of the larger galaxies ought to make gas retention easier , but perhaps that effect is overwhelmed by feedback from the central supermassive black hole . as we have observed @xmath1 percent of our full sample , the conclusions are necessarily tentative at this time .

measurements of the cosmological parameters using distance indicators rely on the redshift - dependent evolution of the distance modulus @xmath3 . the distance modulus is measured as the difference between observed and absolute magnitudes of a `` standard candle '' after k - correction @xcite for the redshifting of its spectrum . the theoretical value for @xmath3 is related to the luminosity distance @xmath4 defined such that a source with luminosity @xmath5 at redshift @xmath6 has observed energy flux @xmath7 as if the energy has been diluted to the surface of a sphere with radius @xmath8 , i.e. @xmath9 ( e.g. @xcite ) . cosmological parameters can then be measured from their functional dependence on @xmath8 ; this technique has been used by two groups with type ia supernovae [ the high-@xmath6 team @xcite and the supernova cosmology project ( scp ) @xcite ] and gives evidence for an accelerating universe . observations are in fact made with photon counters ( ccd s , photo - multipliers ) and the luminosity distance is not the same as the `` photon luminosity distance '' @xmath10 ; if n is the photon luminosity and n is the observed photon flux , then @xmath11 where @xmath12 . this has lead to some confusion as to whether a `` photon '' distance modulus should be used to measure cosmological parameters , whether the magnitude system is photon - based or energy - based , and which k - corrections should be applied . such distinctions which previously have been unimportant are significant as we move into an era of precision cosmology . in this paper we rederive and expand upon the k - correction results of @xcite . we comment on the magnitude system and the johnson - cousins system in particular ( [ mag : sec ] ) . we find that any ambiguity can be removed with the proper definition of the k - correction for which we derive the equations for both photon and energy systems ( [ kcorr : sec ] ) . we conclude that although the differences between the two k - corrections are small , the distinction between energy and photon systems is important for planned future high - precision supernova experiments ( [ con : sec ] ) . the primary standards of a photometric system can have their magnitudes measured either by their energy or photon flux ratios . unless a photon energy conversion correction is later applied , the flux system is determined by the detectors used to measure the primaries . the type of detector used in subsequent observations does not determine whether the magnitude system is photon or energy based ; in principle the color and airmass corrections put observed magnitudes into the primary system . the johnson - cousins magnitude system prevalent today is a photon system , what @xcite describe as `` a system of photoelectric photometry '' . as described in @xcite , their observational setup employed a photomultiplier as a detector , with the counts being the number of `` deflections '' recorded by a potentiometer . after an airmass correction these counts were directly converted to magnitudes . the secondary stars of @xcite ( whose raw data also were obtained with photon counters ) are calibrated via johnson and cousins primary standards and thus must be in the photon system . observed magnitudes are therefore photon - based and should be analyzed as such . an illustrative example of where there is a numerical difference between the two magnitude systems is a star that has the same integrated @xmath13-band energy flux as vega ( which for simplicity we consider to be the zero point of the magnitude system ) but has a different photon flux since it has a different spectral energy distribution ( sed ) . relative magnitude measurements with a single filter of a set of stars with similar spectral energy distributions are independent of whether we are photon counting or measuring energy ; two stars with the same sed but differing brightness will have @xmath14 where @xmath15 and @xmath16 are the stars magnitudes . it follows that since the zeropoint of magnitude system is based on vega , the energy and photon magnitudes of a0v stars are identical : @xmath17 . as an aside , one of the @xcite criteria for a photometric system is `` a determination of the zero point of the color indices in terms of a certain kind of star which can be accurately defined spectroscopically . '' such knowledge , along with the shapes of the pass - band transmission functions , do allow for calculated transformation between photon and energy magnitude systems . indeed , much effort has been placed in measuring and modeling the intrinsic sed of vega ( @xcite and references therein ) . we explicitly review the k - correction calculation of @xcite that has been used in scp cosmological analysis . to remove any ambiguity . we define the k - correction @xmath18 such that @xmath19 where @xmath20 for photon or energy magnitude systems . the observed magnitude in passband @xmath21 is @xmath22 and the absolute magnitude in passband @xmath23 is @xmath24 . we adopt the theoretical expression for the distance modulus , @xmath3 , based on luminosity distance . in other words , the functional form of @xmath25 in equation [ definition ] is identical for photon and energy systems . given @xmath26 as the energy flux density of a supernova 10 parsecs away , we can compute the corresponding energy and photon fluxes at high redshift . @xmath27 the @xmath28 terms in the redshifted flux densities are due to wavelength dilution @xcite . the ratio between high and low - redshift photon flux is a factor @xmath29 greater than the corresponding ratio for energy flux which suffers from redshifted energy loss . more precisely @xmath30 the fact that the relative photon fluxes of high - redshift supernovae are @xmath29 `` brighter '' than energy fluxes can be interpreted as being due to the latter s extra energy loss due to redshift . using the fact that @xmath31 we can compute and compare energy and photon k - corrections , @xmath32 @xmath33 the filter transmission functions are given as @xmath34 where @xmath35 is the rest - frame filter and @xmath36 is the observer filter . ( the transmission functions give the fraction of photons transmitted at a given wavelength where we assume no down - scattering . ) for the standard star ( i.e. calibrator ) sed @xmath37 we assume the existence of a standard star with identical properties as the supernova , i.e. with exactly the same color and observed through the same airmass . pragmatically , this assumption affirms perfect photometric calibration to all orders of color and airmass . for convenience , we choose these secondary standards to have 0 magnitude . in principle , a different standard will be needed for each filter , choice of photon or energy flux , and each source sed . each standard is labeled @xmath38 where @xmath39 and @xmath20 for photon or energy flux as defined earlier . equations [ ekcorr ] and [ gkcorr ] generalize the k - corrections of @xcite and @xmath40 are the same function evaluated at different frequencies . ] and are precisely those given and calculated in @xcite . in that paper , it was found that the differences between the two k - corrections are non - zero but small , @xmath41 magnitudes . they are a function of redshift , filters , and supernova epoch and thus can cause small systematic shifts in light - curve shapes and magnitude deviations in the hubble diagram . the use of the incorrect k - correction will have a significant effect on experiments with small @xmath42 targeted magnitude errors . to illustrate , in figure [ fig ] we plot @xmath43 ( where @xmath44 refers to the passband and not redshift ) for a standard type ia supernova at @xmath13 maximum and 15 rest - frame days after maximum out to @xmath45 . the differences are close to zero at @xmath46 where @xmath47 . beyond this optimal redshift , the differences can be @xmath48 magnitudes . the redder color of the supernova at the later epoch gives relatively larger photon k - corrections over almost all redshifts . the similarity in the two k - corrections is due to two competing terms that nearly cancel . a photon k - correction is @xmath29 brighter because the supernova does not suffer redshifting energy loss . however , the zeropoint of the redder filter used to observe the redshifted supernova is larger since an a0v photon spectrum is flatter than its energy spectrum . this makes the observed supernova magnitude numerically fainter . consider the special case where @xmath49 . with perfect filter - matching the specifics of the supernova spectrum are unimportant and the k - corrections depend on the zeropoints : @xmath50 where @xmath51 is the effective wavelength of the standard through the filter . as long as the standard star is well behaved , we expect the effective wavelength of the redshifted filter to be @xmath29 greater then that of the restframe filter @xmath52 so that @xmath53 choosing filters that accept the same spectral region at both low and high redshifts not only reduce errors but also reduces the difference between energy and photon k - corrections . the effect of using the `` energy '' distance modulus in defining the k - correction in equations [ definition ] , [ ekcorr ] , and [ gkcorr ] are seen in the open - filter k - corrections . when @xmath54 , the energy k - correction is unnecessary and indeed @xmath55 . for the photon k - correction we find @xmath56 , the difference between `` energy '' and `` photon '' distance moduli . a simple measure for the difference between single - filter k - corrections is the ratio in effective wavelength of a redshifted and unredshifted source through that filter . for example , sources with power - law sed s have identical photon and energy k - corrections . for low - redshift objects the difference in effective wavelength should be very small ( unless they have pathological spectra ) and thus make little difference in distance determinations . for example , a type ia supernova at maximum at @xmath57 observed through the @xmath13-band would have a distance modulus error of 0.02 magnitudes if the wrong k - correction were applied . we have shown that the measurements @xmath58 do depend on whether the magnitude system is based on energy or photon flux . although the `` photon luminosity distance '' is shorter than the standard luminosity distance , we can still use the relation @xmath59 with the appropriate definitions of the k - corrections ; the ones of @xcite are appropriate . with this definition , the standard equations linking the energy distance modulus to cosmology are applicable . the johnson - cousins magnitude system is in fact photon - based . therefore , the @xmath60 k - correction should and has been used in the supernova cosmology analysis of the supernova cosmology project . although application of the incorrect k - correction would contribute negligibly to the error budget of the current supernova sample , the distinction is important for precision experiments that require 0.02 magnitude accuracies , such as the supernova acceleration probe . with the choice of well - matched filters , differences between energy and photon k - corrections can be minimal . using the `` count '' distance modulus based on @xmath10 in equation [ definition ] would provide a more physically satisfying definition of the count k - correction . recall that @xmath61 . then the extra @xmath62 in the k - correction would give @xmath63 in other words , the k - correction would depend simply on the ratio of supernova photons in the rest - frame filter and a blue - shifted observer filter , and the zeropoint . this methodology would preserve the physical meanings that we associate with both distance modulus and k - correction . for simplicity , however , we here adopt the energy distance modulus for both k - corrections to be consistent with the literature and to ensure unambiguity when referring to k - corrected magnitudes and distance moduli . we would like to thank arlo landolt and saul perlmutter for reading our manuscript and for their insightful questions and comments . this work was supported by the u.s . department of energy under contract no . de - ac03 - 76sf00098 and a nasa ltsa grant to pen .

the relative brightnesses of standard candles have long been known to be potentially powerful probes of distance . the distance modulus , the difference between observed and absolute magnitudes , has been associated with the values of the cosmological parameters : hubble s constant @xmath0 , the mass density @xmath1 and the cosmological constant @xmath2 . in the literature the relationship between these parameters and the distance modulus is calculated for an energy magnitude system ; the johnson - cousins magnitude system used in observations is in fact a photon - counting system . in this paper , we present the relation between observed and absolute photon magnitudes in terms of the familiar energy distance modulus and derive the correct form of the k - correction . the differences between energy and photon systems are small relative to the measurement errors of contemporary high - redshift supernova searches . the distinction must be made , however , for precision cosmological measurements such as those planned for type ia supernovae .

turbulence is governed by the nonlinear equations of fluid dynamics , but those equations are too complex to be solved analytically . an understanding of the behavior of turbulent flows is better approached using statistical ideas , while also taking into account the few exact results derived by considering isotropic , homogeneous and incompressible turbulence @xcite . in all cases one must invoke statistical averaging , even if the starting point is the navier - stokes equations themselves . in this study statistics and probabilities alone appear ; the underlying equations of fluid dynamics do not enter at all . although a probabilistic approach is taken , it is clear that `` ... turbulent does not mean random . the complex motion of the fluid contains characteristic patterns , events and structures that show through all the randomness '' @xcite . our aim is to unveil this structure of turbulence using tools from information theory @xcite . nevertheless one obtains results that are consistent with those deduced using the traditional approach . these include the existence of a cascade , implying the correlation between eddies of differing sizes . let the velocity of the fluid @xmath0 be a random variable and @xmath1 be one of its possible values . for simplicity of discussion we consider only a single component . there is an associated probability density function @xmath2 , which is determined experimentally by counting occurrences . instead of the velocity we could also consider the vorticity measured at a point or a velocity difference measured between two nearby points in a homogeneous fluid . it will be assumed that the turbulent fluid is in a steady state , making the absolute observation time @xmath3 of little interest . once @xmath2 is in hand , we could proceed to calculate such quantities as the velocity moments @xmath4 . when @xmath1 is replaced with the velocity difference over a scale @xmath5 : @xmath6 , these moments are called the structure functions @xcite . they play an important role in turbulence theory , with particular prominence given to kolmgorov s famous exact solution @xmath7 , where @xmath8 is the energy injection rate @xcite . instead of moving in this traditional direction , we proceed in another . we ask what the probability density function itself has to say . completely random systems have flat distributions , where all possible values have equal weight : @xmath9 constant . in the other extreme , the distribution is a delta function @xmath10 , with only one possible value @xmath11 . this latter scenario corresponds to the ideal laminar state with no fluctuations . the former case is not seen even when the flow is turbulent , because constraints on the energy of the flow force it to be closer to gaussian . now we ask whether there is a way to make this description more quantitative . at the center of information theory is a quantitative measure of the broadness " of probability distributions @xcite . shannon called this the entropy , apocryphally encouraged to do so by von neumann because he could safely hide inside the confusion this term evokes in the physics community @xcite . the most basic form of the entropy , which we shall later revise , is simply @xmath12 where @xmath13 can be thought of as a measure of surprise at observing any particular @xmath1 . the form of eq . [ eq : h ] is the same as for the energy states in , @xmath14 the canonical ensemble of statistical mechanics @xcite . the astute reader will notice we have used a sum @xmath15 instead of an integral @xmath16 . shannon s original work was on messages with discrete variables ( like the letters in the english language ) , and while there is a generalization to continuous variables @xcite , we will switch to the discrete form here . ( the discretization of continuous variables needs to be done carefully , and we leave this issue for later . ) clearly @xmath17 is large when @xmath2 is broad and small if it is narrow . large uncertainty means large @xmath17 . if we are measuring the velocity @xmath1 in a laboratory and adopt the interpretation that the readout on our instrument is the fluid system s message " to us , then @xmath17 is the amount information we obtain from our measurement . we are told nothing new by repeatedly making measurements of laminar flow , since it never changes , but we are always getting new information from turbulent flow . r. s. shaw was the first to recognize this information production as a general feature of chaotic systems @xcite . an analogous observation outside of fluid dynamics is an image taken from a newspaper . the image is created by varying the local density of black dots of ink . just as some images are characterized by wild variations in paint color ( a jackson pollock painting is a good example ) , others , such as many mondrian paintings , show small variations , and have simple geometrical forms . the information or @xmath18 is larger in the first of these . it is closer to high reynolds number flows and the mondrian painting is akin to flow at moderate or low reynolds number . this visual link is displayed in a juxtaposition of these paintings with the velocity field in a pipe in fig . [ pollock ] . if information theory s utility were limited to the above quantification of uncertainty through @xmath18 , it would indeed be of limited use . however , @xmath18 is the basis for extracting other quantities , like the mutual ( or shared ) information @xmath19 between two quantities @xmath20 and @xmath21 @xcite . these quantities will be introduced in the forthcoming examples as the need arises . the emphasis here is on the application of these tools to real data taken in the laboratory or calculated on a computer . we turn first to demonstrating experimentally the assertion made earlier about the entropy of laminar and turbulent flow . we perform measurements of the axial velocity @xmath1 at the centerline of a long ( @xmath22 cm ) , cylindrical pipe as a function of time using a dantec laser doppler velocimeter ( ldv ) and hollow glass , silver - coated 10 @xmath23 m particles for scattering . the reynolds number here is defined as @xmath24 , where @xmath0 is the cross - sectionally averaged velocity , and @xmath25 cm is the diameter , with @xmath26 the kinematic viscosity of water . a schematic of the setup is shown in fig . [ pipe_setup ] . in pipes , as in many other shear flows , the system can in principle remain laminar to infinite @xmath27 @xcite . however , turbulence can be triggered by a finite perturbation , such as an obstacle . doing so results in an intermittent time series of turbulent and laminar patches @xcite . [ slug ] shows an interval of time when the flow at a point is transitioning between the two states . the higher value is the laminar state and the lower is the turbulent . the pdfs to the right of the time series confirm that even the laminar flow has some fluctuations ( either instrumental or from the setup ) , although they are smaller than the turbulent ones . while the entropy is theoretically zero for laminar flow , since there is only one value of the velocity , the presence of noise hinders a direct experimental confirmation of this . we begin by determining @xmath2 . binning data to make a histogram of inevitably finite experimental or numerical data is a familiar procedure . in fig . [ slug ] , very fine bin sizes were used so that to the naked eye the curve looks continuous . there is no problem using these same bin sizes for calculating @xmath17 , but it should not come as a surprise that the bin size choice affects @xmath17 . figure [ partition ] shows how this binning works . calling @xmath8 the bin size , a continuous stream of data is converted to discrete data or symbols , each representing a range of values . if @xmath8 is small , then the number of symbols , the alphabet size , @xmath28 is large and vice - versa . to be examined is the effect of varying @xmath8 on the pdf , and hence @xmath18 . figure [ pdfs ] shows @xmath1 for several values of @xmath8 . the general shape is the same , but the gaussian character is not clear but for small @xmath8 . what value of @xmath8 should be used ? this is not an easy question to answer . it is tempting to try the limit @xmath29 , as is done when calculating @xmath14 the kolmogorov - sinai entropy @xcite , but it should be clear that this is not an option for real data . an additional complication is noise , as highlighted by the laminar portion of fig . if @xmath8 is below the noise , one gets a different value from the theoretical @xmath30 . it turns out that it may not matter , depending on the question one is trying to answer . arbitrarily , we choose @xmath31 , the standard deviation for the laminar noise and the turbulent slugs respectively ( separately ) and proceed to see how information theory can distinguish between the two . this corresponds to the coarsest pdf in fig . if we use a different @xmath8 , the results are qualitatively the same . the pdfs of both of the noisy laminar data and the turbulent data are nearly gaussian and will nearly collapse when normalized @xmath32 . as a result , the two values of @xmath18 are nearly identical . true noise ( often called shot noise @xcite ) is uncorrelated with itself at all finite lag times . an even stronger statement is to say that it is statistically independent of itself at different times . we can take advantage of this fact by considering finite blocks of the velocity time series : @xmath33 $ ] , where @xmath34 is the inverse mean sampling rate of the ldv . the probabilities of these blocks directly relate to the inter - relationships between its members . consider the so - called block entropy @xcite : @xmath35 if there is no statistical dependence between any of the data points inside the blocks ( no correlations ) then @xmath36 . by an application of jensen s inequality @xcite , this is the maximum value : @xmath37 . it is lowered by any statistical dependence between the @xmath0 s inside of @xmath38 , @xmath39 temporal or spatial correlations . this observation can be exploited to distinguish the shot noise , seen even in laminar flows . the above definition is applied to @xmath40 for laminar and turbulent data from the pipe measurements . it is divided by @xmath41 , so that if the data is truly random , it will return to the value @xmath42 . as expected , the random noise in the laminar flow has no correlations , so it is hardly reduced at all by this division , while the correlations inherent in the kolmogorov picture of turbulence @xcite reduce the entropy for the turbulent flow , as shown in fig . [ slug_h ] . it is instructive to examine how @xmath40 depends on @xmath41 . this function is not well - behaved at very large @xmath41 . let @xmath43 be the total number of velocity data points in a typical run ( typically , @xmath43 is of order @xmath44 . ) when the number @xmath45 is too small , there are too few blocks to determine the occurrence probabilities needed to evaluate @xmath40 , resulting in the data appearing to be _ less _ random than it really is . this effect is compounded if velocities are correlated , as in turbulence , where the correlation length can be large and a large @xmath41 is needed to capture the physics . figure [ slug_h ] , shows @xmath46 @xmath47 @xmath41 for the turbulent fluctuations in slugs and the shot noise in the laminar flow . the laminar measurements show a dependence on @xmath41 for the physically uninteresting reason described above that the data are not collected for a long enough time interval to accurately measure probabilities appearing in @xmath40 . this same phenomenon plagues the slug curve , and so researchers typically identify the inflection point as being important @xcite . if @xmath46 did not drop off , it would remain constant and this limit is called the entropy rate or density @xcite : @xmath48 there are three equivalent ways to define @xmath49 . the first is described above , and the second is @xmath50 while the third is @xmath51 here @xmath52 is the conditional entropy ( @xmath20 conditioned on @xmath21 ) . the entropy density converges to a finite value because less and less information is gained on increasing @xmath41 by one unit . the utility of @xmath49 in elucidating turbulence will be explored further in the soap film experiments to be described next . the gravity - driven soap film is a mixture of soap detergent and water , with small density - matched glass spheres added for the velocity measurements . fig . [ setup ] is a diagram of the experimental setup . a laser doppler velocimeter ( ldv ) is used to measure the velocity components in the streamwise @xmath1 direction . by adjusting the flow rate and the channel width , several decades of reynolds number @xmath27 can be explored . here @xmath53 , where @xmath54 is the rms velocity and @xmath55 is the channel width . for more experimental details , we refer the reader to ref . @xcite . using eq . [ entropydensity ] , we go on to calculate the entropy rate for turbulence in a soap film . here , depending on the forcing , three entirely different kinds of behavior can be generated . if the soap film travels between rough walls , the perturbation they steadily create an inverse cascade of energy from smaller to larger eddies @xcite . if , instead , the film is penetrated by a comb , a row of @xmath56 1 mm rods , a different type of cascade is created ; the rods create vortices which cascade downscale to the smallest sustainable size : the direct enstrophy cascade @xcite . the accompanying energy spectra @xmath57 are as seen in fig . [ spectra ] . here @xmath58 is wavenumber in inverse cm and @xmath57 has units of kinetic energy per kg per unit wave number . a final case is when the perturbations of the comb are too weak to initiate a cascade at all , resulting in a flat @xmath57 . besides @xmath49 , another quantity is also plotted in fig . this is an alternative method for estimating the information and in the limit of infinite data the two coincide . computer memory is necessarily limited , making it useful to store and transmit information in as compact a form as possible . the total amount of memory necessary to send or store a message can be shortened by ( re-)coding the words to minimize their length . one example is using a coding scheme that assigns a small number symbols to words that appear with high frequency , as in morse code where @xmath59 is coded with the shortest symbol , a dot. in turbulence the probability distribution like in fig . [ pdfs ] suggests something similar might be done . remarkably , shannon proved that the limit on @xmath60 compression scheme is given by the entropy of the message @xcite . if the original length or size of a message is @xmath61 , then after the compression algorithm does its work , the new size @xmath62 satisfies the inequality @xmath63 while shannon provided no hints as to how equality might be approached , substantial work has been done in his wake to satisfy the equality in the limit @xmath64 . these coding schemes are called optimal , an example being the lempel - ziv algorithm @xcite . as expected , the compression ratio @xmath65 in fig . [ h_l ] is equal to or greater than @xmath49 ; it should not be smaller . binarizing the data gives a rough description , so it is not surprising that the difference between @xmath65 and @xmath49 is revealed only when the data is segmented into ten values . why does @xmath49 decrease as @xmath27 increases ? presumably this because increasing the strength of the turbulence increases the correlations between different spatial scales , and correlations always @xmath66 the surprise element in all observations @xcite . but a puzzle remains : when @xmath27 is decreased sufficiently , the flow must become laminar , in which case @xmath49=0 . therefore @xmath49 must go through a maximum - at a value that these experiments can not measure . a strange prediction is suggested by fig . [ h_l ] . if we treat @xmath67 as a state function in thermodynamics , then changing @xmath27 simply moves the system along this unique curve . consider the case of decaying turbulence , as with a comb in a soap film . near the comb the flow exhibits the enstrophy cascade and @xmath27 as defined here measurements made progressively further away from the comb have a lower energy due to the decay , and so a lower @xmath27 . at the same time , @xmath49 will increase until there is a transition , apparently continuous with respect to @xmath49 , from an enstrophy cascade to an inverse energy cascade . this remarkable transition has , in fact , been observed in soap films , although the mechanism has been attributed to wall shear effects @xcite . to further illustrate some of the tools of information theory in practice , we turn to a toy model of turbulence designed to mimic the essential properties of turbulence . the gledzer - ohkitani - yamada ( goy ) shell model is the simplest model with a cascade of energy @xcite , but it still yields to theoretical analysis and can easily be numerically integrated even on a laptop computer . herein lies its utility . as long as its limits are kept in mind , the goy model can be a useful playground for new ideas that can later be applied to full - blown navier - stokes turbulence . this approach has led to the discovery of intermittency in the helicity cascade of 3d turbulence @xcite . as kadanoff quipped , `` models are fun , and sometimes even instructive '' @xcite . in the goy model , each variable ( shell ) corresponds to velocity fluctuations on a different spatial scale . these shells , however , live in fourier space , and so the independent variable is the wavenumber @xmath58 . ( this is also why the velocity of the shells are complex ) . it is useful to think of this model as a truncation of the navier - stokes equation in fourier space . there are a finite number ( @xmath68 ) of shells and we denote by @xmath69 any particular shell ( from 1 to @xmath68 ) . following custom , @xmath68 is set to 22 @xcite . the wavenumbers @xmath70 are picked to be a fixed logarithmic distance apart : @xmath71 , where here @xmath72 and @xmath73 . large @xmath69 corresponds to small scales , while small @xmath69 refers to large scales . the governing set of equations is @xmath74 where @xmath75 is the forcing , @xmath76 , and @xmath77 denotes the complex conjugate . the variables @xmath78 , @xmath79 and @xmath80 are shell dependent but constant in time . these determine the strength of energy flow between scales . we refer the reader to the accessible review by kadanoff @xcite or the detailed review by biferale @xcite for more particulars . following the numerical scheme outlined in ref . @xcite , the viscosities are assigned the values @xmath81 , @xmath82 , @xmath83 , where the reynolds number @xmath84 . the equations are integrated using matlab . the energy spectra are shown below in fig . [ goy_spectra ] . as the viscosity decreases ( @xmath27 increases ) , the kolmogorov -5/3 scaling is present at higher and higher wavenumbers . what sort of questions can be address with the tools of information theory ? consider one of the most fundamental concepts in turbulence phenomenology , the universality of small scales . in the traditional picture of the turbulent cascade , energy is injected at some large scale and then transferred to smaller and smaller scales . in order for the scaling of the velocity differences to depend only on the local scale @xmath85 and the energy injection rate , it must `` forget '' about the large scales . or , as kadanoff puts it , the system remembers as little as it possibly can about the conditions at which energy is added or dissipated @xcite . this forgetfulness is readily quantified using information theory , in particular through the mutual information . if one scale forgets about the other , then the mutual information between them will be small ( identically zero if statistically independent ) : @xmath86 where @xmath87 is the energy at @xmath58 and @xmath88 is the spacing between adjacent shells . figure [ forcing_mutinfo ] is a plot the instantaneous mutual information between the energy each scale and at the forcing scale ( @xmath69 = 4 shell ) . apart from the peak at @xmath69 = 4 , where the mutual information is now equal to the self - information ( the entropy ) , the shared information falls off algebraically as -1/4 until the dissipative scales are reached . thus the inertial scales do not completely forget the details of the forcing , although the shared information becomes very small . indeed , the goy model is well known to exhibit the same intermittency phenomenon ( deviations from kolmogorov and violations of the universality assumption ) as fluid turbulence @xcite . while the entropy plays the most fundamental role , that of a measure , in shannon s information theory , it is the mutual information that has proved the most useful in the field of communications . in any causal physical relationship , or interaction , one system or subsystem will exchange with another not only energy or momentum but also information . ( indeed , it is well known that the speed of light restriction of special relativity is most properly formulated in terms of information transfer , albeit not explicitly in the shannon sense . ) it is reasonable to consider whether the cascade may also be a communication channel . to do so , let us now consider the local transfer of information between adjacent shells using the mutual information . since the information source , just like the energy , must be at the forcing scale , we expect information to flow downscale . however , it is well known that there is `` backscatter '' of energy ( enstrophy ) even in the 3d energy ( 2d enstrophy ) cascade . with this in mind , we also consider the transfer of information upscale , as done in @xcite . the cascade is a dynamical process . an amount of energy at a wavenumber @xmath58 at time @xmath3 is transferred to wavenumber @xmath89 in a time @xmath34 . to reflect this , we introduce a time lag into the mutual information . a large shell ( eddy " ) at an arbitrary time @xmath3 will share information forward in time to a small shell , so @xmath90 will be large if information is going downscale , whereas the following will be large if information is going upscale @xmath91 the use of this time lag is similar to its use in @xcite . subtracting the transfer upscale from that downscale , in fig . [ info_transfer ] we indeed find a net downscale transfer that is positive only in the inertial range and increases in magnitude as @xmath27 increases . thus there exists a companion information cascade along with the energy cascade in the goy model . it would be interesting to determine if the same is true for 3d and 2d turbulence . the presence of an information flux is not only related to intermittency , but suggests a further useful constraint on the physics of turbulence . while information theory was created to characterize messages coded in the form of words , it applies equally well to experimental observations in which the words of a text are replaced by measured quantities . in this work , information is applied to three - dimensional turbulent flow in a long pipe , to two - dimensional turbulence in a gravity - driven soap film , and to a mathematical model that takes into account the turbulent cascade of energy from larger to smaller eddy sizes . the goal of the work is to demonstrate that information theory can illuminate physical observations , even when the equations governing the system s behavior are intractable or may not even be known . in this study , no appeal is made to the navier - stokes equations , which govern the fluid flows under observation . even when true velocity fluctuations are absent , as in laminar flows , shot noise ( also called poisson noise ) , can appear as a confounding effect . the goal of the work is to introduce the reader to the information theory approach , and to demonstrate its usefulness . durst , f. , nsal , b. : forced laminar - to - turbulent transition of pipe flows . . mech . * 560 * , 449 - 464 ( 2006 ) mullin , t. : experimental studies of transition to turbulence in a pipe . * 43*(1 ) , 1 - 24 ( 2011 ) frigg , r. : brit . sci . * 55 * , 411 ( 2004 ) adrian , r.j . , yao , c.s . : power spectra of fluid velocities measured by laser doppler velocimetry . fl . * 5*(1 ) , 17 - 28 ( 1986 ) schrmann , t. , grassberger , p. : entropy estimation of symbol sequences . chaos * 6*(3 ) , 414 - 415 ( 1996 ) ziv , j. , lempel , a. : compression of individual sequences via variable - rate coding . ieee trans . * 24 * , 530 ( 1978 ) chen , q. , chen , s. , eyink , g.l . , holm , d.d . : intermittency in the joint cascade of energy and helicity . lett . * 90*(21 ) , 214503 ( 2003 ) materassi , m. , consolini , g. , smith , n. , de marco , r. : information theory analysis of cascading process in a synthetic model of fluid turbulence . entropy * 16 * , 1272 - 1286 ( 2014 ) kadanoff , l. , lohse , d. , wang , j. , benzi , r. : scaling and dissipation in the goy shell model . phys . fl . * 7*(3 ) , 617 - 629 ( 1995 ) biferale , l. : shell models of energy cascade in turbulence . . mech . * 35*(1 ) , 441 - 468 ( 2003 ) vastano , j.a . , swinney , h.l . : information transport in spatiotemporal systems . lett . * 60 * , 1773 - 1776 ( 1988 )

a message of any sort can be regarded as a source of information . claude . e. shannon showed in the last century that information ( `` what we do nt already know '' @xcite ) is equivalent to the entropy as defined in statistical mechanics @xcite . a string of experimental observations is like a succession of words ; they both convey information and can be characterized by their entropy . for the fluid flow measurements and simulations to be discussed here ( pipe and soap film flow , goy model ) , the entropy depends on controllable parameters such as the reynolds number . the information theory approach is applicable to measurements of any type including those governed by intractable equations or systems where the governing equations are not known . this contribution is dedicated to the memory of leo kadanoff , an inspiring teacher and one of the most important scientific leaders of the last half century .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Acadia National Park Boundary Clarification Act''. SEC. 2. ACADIA NATIONAL PARK BOUNDARY CLARIFICATION. (a) In General.--Section 101 of Public Law 99-420 (16 U.S.C. 341 note) is amended-- (1) in the first sentence, by striking ``In order to'' and inserting the following: ``(a) Boundaries.--To''; (2) in the second sentence-- (A) by striking ``The map'' and inserting the following: ``(d) Availability of Maps.--The maps described in subsection (a) and subsection (b)''; and (B) by striking ``and it shall'' and inserting ``and shall''; and (3) by inserting after subsection (a) (as so designated) the following: ``(b) Schoodic Peninsula Addition.--The boundary of the Park is confirmed to include approximately 1,441 acres of land and interests in land, as depicted on the map entitled `Acadia National Park, Hancock County, Maine, Schoodic Peninsula Boundary Revision', numbered 123/ 129102, and dated July 10, 2015. ``(c) Ratification and Approval of Acquisitions of Land.--Congress ratifies and approves-- ``(1) effective as of September 26, 2013, the acquisition by the United States of the land and interests in the land described in subsection (b); and ``(2) effective as of the date on which the alteration occurred, any alteration of the land or interests in the land described in subsection (b) that is held or claimed by the United States (including conversion of the land to fee simple interest) that occurred after the date described in paragraph (1).''. SEC. 3. LIMITATION ON ACQUISITION OF LAND FOR ACADIA NATIONAL PARK. (a) Limitation.--Except as provided in subsection (b), the Secretary of the Interior (referred to in this Act as the ``Secretary'') may only acquire land or interests in land within the boundary of Acadia National Park or outside the boundary of Acadia National Park in Hancock or Knox County, Maine, in accordance with Public Law 99-420 (16 U.S.C. 341 note). (b) Exception.--The Secretary may conduct exchanges for land and interests in land described in subsection (a) in accordance with section 102901 of title 54, United States Code. SEC. 4. SOLID WASTE MANAGEMENT. Section 102(f) of Public Law 99-420 (16 U.S.C. 341 note) is amended, in the second sentence, by striking ``toward the cost of constructing'' through the period at the end of the sentence and inserting the following: ``$350,000 to a regional consortium composed of units of local government located on, or in the vicinity of, Mount Desert Island, Maine, that is established for the purpose of improving the management of the disposal and recycling of solid waste.''. SEC. 5. ACADIA NATIONAL PARK ADVISORY COMMISSION. (a) In General.--The Secretary shall reestablish and appoint members to the Acadia National Park Advisory Commission in accordance with section 103 of Public Law 99-420 (16 U.S.C. 341 note). (b) Conforming Amendment.--Section 103 of Public Law 99-420 (16 U.S.C. 341 note) is amended by striking subsection (f). SEC. 6. REPEAL OF CERTAIN PROVISIONS RELATING TO ACADIA NATIONAL PARK. The following are repealed: (1) Section 3 of the Act of February 26, 1919 (40 Stat. 1178, chapter 45). (2) The first section of the Act of January 19, 1929 (45 Stat. 1083, chapter 77). SEC. 7. MODIFICATION OF USE RESTRICTION. The Act of August 1, 1950 (64 Stat. 383, chapter 511), is amended-- (1) by striking ``That the Secretary'' and inserting the following: ``SECTION 1. CONVEYANCE OF LAND IN ACADIA NATIONAL PARK. ``The Secretary''; and (2) by striking ``for school purposes'' and inserting ``for public purposes, subject to the conditions that use of the land shall not degrade or adversely impact the resources or values of Acadia National Park and that the land shall remain in public ownership for recreational, educational, or similar public purposes''. SEC. 8. CONTINUATION OF CERTAIN TRADITIONAL USES. Title I of Public Law 99-420 (16 U.S.C. 341 note) is amended by adding at the end the following: ``SEC. 109. CONTINUATION OF CERTAIN TRADITIONAL USES. ``To allow for the continuation of traditional harvesting and aquaculture of clams, worms, mussels, periwinkles, and other marine organisms (as defined in section 6001(26) of title 12 of the Maine Revised Statutes (as in effect on the date of enactment of the Acadia National Park Boundary Clarification Act)) in intertidal areas in the Park, the Secretary shall permit the harvesting of the marine organisms in the Park in accordance with the laws (including regulations) of the State of Maine and units of local government in the State of Maine.''. SEC. 9. CONVEYANCE OF CERTAIN LAND IN ACADIA NATIONAL PARK TO THE TOWN OF BAR HARBOR, MAINE. (a) In General.--The Secretary shall convey to the Town of Bar Harbor (referred to in this section as the ``Town'') all right, title, and interest of the United States in and to the .29-acre parcel of land in Acadia National Park identified as lot 110-055-000 on the tax map of the Town for section 110, dated April 1, 2015, to be used for a solid waste transfer facility. (b) Reversion.--If the land conveyed under subsection (a) is used for a purpose other than the purpose described in that subsection, the land shall, at the discretion of the Secretary, revert to the United States.

Acadia National Park Boundary Clarification Act This bill confirms that the boundary of Acadia National Park in Maine includes approximately 1,441 acres of land and interests in the Schoodic Peninsula. The bill ratifies and approves: the acquisition by the United States of such land and interests, effective as of September 26, 2013, and any alteration of such land or interests held or claimed by the United States that occurred after such date. The Department of the Interior may only acquire land or interests in land within or outside of the boundaries of the park in Hancock or Knox Counties, Maine, in accordance with the statute that established the park's boundaries, except that Interior may conduct exchanges for lands and interests in accordance with the provisions relating to conveyances of certain property and interests in property acquired by Interior that are within units of the National Park System or related areas. Interior shall contribute a specified amount to a regional consortium composed of units of local government on or in the vicinity of Mount Desert Island that was established to improve the management of the disposal and recycling of solid waste. Interior shall reestablish and appoint members to the Acadia National Park Advisory Commission. Certain land in the park that was conveyed by Interior to the town of Tremont, Maine, shall no longer be used exclusively for school purposes, but for public purposes, subject to the conditions that: (1) use of such land shall not degrade or adversely impact the park's resources or values; and (2) such land shall remain in public ownership for recreational, educational, or similar public purposes. Interior shall permit the harvesting of the marine organisms within the park according to the laws of the state of Maine and its local governments in order to allow for the continuation of traditional harvesting and aquaculture of clams, worms, mussels, periwinkles, and other marine organisms within intertidal areas in the park. Interior shall convey to the town of Bar Harbor a specified .29-acre parcel of land within the park to be used for a solid waste transfer facility.

This is the dramatic tail -- er, tale! -- of Larry the Lobster, a giant 15-pound crustacean who narrowly escaped becoming dinner at a Florida restaurant and who is now headed to Maine, where his "rescuers" hope he will get to "live a better life." The lucky lobster first rose to fame in the town of Sunrise, Florida, after a local seafood restaurant owner bought Larry from a vendor, was "astounded by his big size" and thus went to local news outlets to share his "rare find." "This lobster came in at a whopping 14.98 pounds," Joe Melluso, owner of Tin Fish, told ABC News. "Jumbo lobsters we get are usually between three and five pounds, SO this was over three times the size of a regular jump lobster." Melluso told local news he believed the lobster was 110 years old, given its size. However, a lobster scientist and researcher from Maine said, though the lobster is probably "quite old," 110 years "might be a bit of an exaggeration." Joe Melluso/Tin Fish "There's no confirmed way to tell a lobster's age, though you can make a guesstimate based on their size and current growth models," said Dr. Robert Bayer, executive director of the Lobster Institute in Maine. Bayer told ABC News Larry was more likely between 60 and 80 years old. Nonetheless, news of the giant lobster caught the attention of several diners in the area, Melluso said, adding that one gentleman bought and reserved it for a family dinner on Tuesday evening at the Tin Fish restaurant. But just before Larry could be cooked, several animal activists called Melluso, asking him if they could save the lobster and just reimburse the gentleman who originally bought it. "They really opened up my eyes and it got me a little emotional," Melluso said. "We went ahead and donated the lobster to them." And so rather than being put into a pot, the lobster was put into a special container with salt water to be shipped to Maine, according to Brooke Estren, an attorney based in Boca Raton who coordinated the rescue and named the lobster Larry. Brooke Estren "One of my friends, who works for an animal rescue based in Costa Rica, was able to contact the director of the Maine State Aquarium, and we're sending Larry off there now," Estren told ABC News on Wednesday. Larry is expected to arrive at the aquarium sometime today, according to Jeff Nichols, communications director for the Maine Department of Marine Resources, which operates the Maine State Aquarium. "If it does arrive here, and it's in good health, aquarium staff will quarantine it," Nichols told ABC News. Nichols explained that it was "impossible to tell" what would happen to Larry after the quarantine. However, Estren told ABC News she hoped that Larry would get to "live a better life" whether the aquarium decides to keep him or set him back free in the ocean. ||||| SHARE COPY LINK A group of South Florida seafood lovers decided that a possibly 110-year-old lobster shouldn't be eaten, but saved. They bought him from Sunrise's Tin Fish restaurant and, with the assistance of Tin Fish owner Joe Melluso and Chef Dennis Alvarez, David Neal dneal@miamiherald.com A group of South Florida seafood lovers decided that a possibly 110-year-old lobster shouldn't be eaten, but saved. They bought him from Sunrise's Tin Fish restaurant and, with the assistance of Tin Fish owner Joe Melluso and Chef Dennis Alvarez, David Neal dneal@miamiherald.com

– Larry the Lobster lives another day, thanks to a group of rescuers who saved the 15-pound crustacean from ending up on Florida diners' plates, the Miami Herald reports. Even more astounding: Although figuring out a lobster's age is an inexact science, the owner of the restaurant that acquired Larry estimates, based on the lobster's growth indicators, that the crustacean is about 110 years old. Tin Fish owner Joe Melluso tells ABC News that the lobsters he buys from vendors usually top out at 5 pounds. A picture of Larry circulated on social media, and a family reserved him for Tuesday night's dinner—until a group of other locals caught wind. Real estate lawyer Brooke Estren and friends pitched in $300 to buy him, plus shipping costs to send him to the Maine State Aquarium, where he'll be examined and either housed permanently or put back in the sea. The group wrapped Larry in a saltwater-soaked towel, packed him in a special shipping container, and mailed him to Maine Wednesday. "If you're going to live 110 years, you deserve to live and not be someone's dinner," Estren tells the Herald. And even though Larry may not be quite as ancient as Melluso guessed he is (the executive director of Maine's Lobster Institute pegs him as probably somewhere between 60 to 80 years old), the restaurant owner got "choked up" contemplating all the effort put into saving the lucky lobster, the Herald notes. "My whole life's been about fish and seafood," Melluso says. "[Larry's rescuers are] looking to protect and serve the species in a responsible way. I should be thinking like that." (A rare split-colored lobster was caught off the Maine coast last year.)

severe sepsis is still the leading cause of death in surgical intensive care units and can be held responsible for approximately 9% of deaths per year in usa and germany . in the course of ongoing sepsis , , the lung can either be the source of infection or is remotely affected by systemic inflammation as bacterial degradation products reach this organ via the bloodstream . in both cases , an extensive release of proinflammatory cytokines and chemokines induces migration of neutrophils , fibroproliferation , and reorganization of lung tissue . an accompanying disruption of the alveolar - capillary interface and consecutive leakage of protein - rich fluid into the interstitial and alveolar space causes hypoxemia and reduces lung compliance . acute lung injury ( ali ) or its severe form , the acute respiratory distress syndrome ( ards ) , constitute clinical manifestations of the pathological process and develop in 40% of the patients suffering from sepsis . toll - like receptors ( tlrs ) act as pivotal signalling proteins of the inflammatory response during sepsis . gram - negative bacteria release the tlr4 ligand lipopolysaccharide ( lps ) whereas the cell wall component lipoteichoic acid ( lta ) from gram - positive bacteria is primarily bound by tlr2 . both , tlr2 and tlr4 are localized in the cell membrane while tlr9 is localized in lysosomes and recognizes bacterial dna from both gram - positive as well as gram - negative bacteria . bacterial dna contains cpg - odn motifs , which are unmethylated cg dinucleotides prevalent in bacterial but not in mammalian dna . tlrs are differentially expressed in many organs including heart and lung as well as various cell types . it has been shown that tlrs are involved in a number of inflammatory diseases of the lung , such as allergic asthma , autoimmune lung injury , and pneumonia . bacterial components induce the expression of inflammatory mediators such as proinflammatory cytokines and chemokines , which are highly relevant for the pathogenesis of pulmonary inflammation and injury [ 1214 ] . both attract and activate immune cells infiltrating the lung . also , during sepsis , they participate in disrupting the alveolo - capillary structure , rupture of basal membranes , and interstitial matrix remodelling . the integrity of the extracellular matrix ( ecm ) is controlled by a dynamic equilibrium of synthesis and local degradation . matrix metalloproteinases ( mmps ) are the main physiological mediators of ecm degradation , which are also upregulated under pathological conditions like pulmonary inflammation or sepsis . they are primarily regulated by a class of endogenous inhibitors , tissue inhibitors of mmps ( timps ) . there has been a significant gain of knowledge about the high complexity of organ - specific tlr signalling in the lung . this organ exhibits a tlr pattern , which derives in part from parenchymatous cells as well as from immune cells like neutrophils . hence , it may be speculated that the inflammatory response depends on specific tlr stimulation , and thus , various virulence factors might induce different inflammatory responses . it can be hypothesized that different organs express specific tlr patterns , which serve their need in defense against pathogens . an accurate characterization of tlr expression and signalling as well as the investigation of consecutively induced inflammatory mediators is essential for understanding a differential inflammatory response to varying stimuli . it might be the fundament for developing efficient strategies for diagnosis and treatment of sepsis . however , the number of studies comparing the influence of different tlrs in vivo is rare . in particular , a comparison of ligands for tlr2 , -4 , and -9 in vivo in the lung has not yet been performed . therefore , we analysed the influence of three different tlr ligands ( lta , lps , and cpg - odn ) on the expression of tlrs , cytokines , chemokines , mmps , and timps in the murine lung . also , the subsequent activities of mpo , mmp-2 , and -9 and the level of tnf- protein in pulmonary tissue were investigated . the stimuli were applied remotely ( intraperitoneal , i.p . ) to simulate the progression of sepsis . lipopolysaccharide ( lps ) was from escherichia coli ( e. coli , 0 : 111 , sigma aldrich chemie gmbh , munich , germany ) . lipoteichoic acid ( lta ) was kindly provided by s. morath , university of konstanz , germany ( charge mgm5 - 10 ) and prepared as described before . the lps contamination of the lta preparations was less than 1 eu / mg as determined by the limulus amoebocyte lysate assay ( charles river , charleston , sc ) . an immunostimulatory cpg - odn ( 1668 thioat , sequence : gctagacgttagcgt ) was purchased from tib - molbiol ( tib - molbiol gmbh , berlin , germany ) . 158 male c57bl/6 mice 12 weeks of age from charles river ( sulzfeld , germany ) were incorporated in the study . mice were housed in pathogen - free cages with free access to water and standard rodent chow . injections of pbs or different tlr ligands , that is , equipotent doses ( see below ) of either lta ( 15 mg / kg ) , lps ( 20 mg / kg ) , or 1668 thioat ( 1 nmol / g ) . 30 min before stimulation with cpg - odn , mice received 1 mg / kg d - galactosamine ( d - galn ; roth , karlsruhe , germany ; in control experiments d - galn alone did not induce an inflammatory response ; data not shown ) . at the end of the experiments , mice were sacrificed under anaesthesia with isoflurane 2.5 vol.% ( forene , abbott gmbh , wiesbaden , germany ) . the animals were handled according to the principles of laboratory animal care ( nih publication no . 85 - 23 , revised 1996 ) , and animal procedures were approved by the local committee for animal care . ( n = 3/group ) were stimulated with lps ( 20 mg / kg i.p . , according to ) , cpg - odn ( 1 nmol / g i.p . , according to ) . to determine potency of the applied concentrations of the three tlr ligands , undiluted serum from stimulated mice was tested in vitro on fibroblast cultures . the test of serum was chosen , as during a remote inflammation virulence factors are transported to the lung via the blood stream . briefly , 2 h after stimulation , serum was taken , and murine fibroblast tumor cells were incubated with this serum and stained to determine viability . binding of tnf- and - to surface receptors initiates lysis in certain types of cells . the tnf activity assay employs tnf - sensitive , actinomycin d - treated murine l929 fibroblasts to quantify tnf activity . murine fibroblast tumor cells were grown in rpmi 1640 medium containing 10% fetal calf serum ( fcs ) , 5 mm l - glutamin , 25 mm hepes , 5 mm sodium pyruvate , and 100 u penicillin and streptomycin , respectively . a 96-well plate containing 5 10 cells per well was incubated over night in a humidified incubator ( 37c , 93% o2 , 7% co2 ) . medium was removed and fresh serum or medium or tnf- standard ( rtnf , sigma aldrich , munich , germany ) were added . 10 l of 1 : 50 diluted actinomycin d ( sigma aldrich ) was given to each well and incubated over night . after removal of the supernatant , cells were fixed with 5% formalin for 10 min . 100 l of 0.05% crystal violet ( sigma aldrich ) in 20% ethanol was added to each well followed by destaining with tab water , and , finally , plates were dried . absorbance was measured at 590 nm after dilution of the stain with 100 l methanol per well . increased staining and absorbance corresponded to increased l929 fibroblast viability and decreased lytic effects of tnf . pulmonary protein extracts were prepared using the ne - per nuclear and cytoplasmic extraction reagents ( pierce biotechnology , rockford , il , usa ) according to the manufacture 's protocol and as published previously . the tissue weight was determined , and the appropriate amount of cer i ( 10-fold excess over the weight of tissue ) containing 0.5 mg / ml benzamidine ( roche , basel , switzerland ) , 2 g / ml aprotinin ( roche ) , 2 g / ml leupeptin ( roche , basel , switzerland ) , and 0.75 mm pmsf ( roche , basel , switzerland ) was added . cer ii was added , incubated again for 1 min on ice , and centrifuged for 5 min at 13,200 u / min ( 16,110 g ) and 4c . the supernatant was transferred to a prechilled tube and used as cytoplasmic fraction for analysis of zymographic activity . after vortexing and incubation according to manufacturer 's protocol , the sample was centrifuged again for 10 min at 16,110 g. the supernatant was immediately transferred to prechilled tubes and used as nuclear extract for determination of nfb - dna binding activity . the protein concentration was assessed by use of a bicinchoninic acid assay kit ( pierce biotechnology , rockford , il , usa ) according to the manufacturer 's protocol . nfb activity was evaluated by electrophoretic mobility shift assay ( emsa ) 2 h after stimulation ( n = 3/group ) . nuclear extracts used in supershift and competition experiments were harvested from snap frozen lungs as described above . , santa cruz ca , usa ) nfb : 5-agt tga ggg gac ttt ccc agg c-3 ( sc-2505 ) ) were end - labelled with ( -32p ) atp ( amersham , freiburg , germany ) . binding reactions ( 25 l total ) were performed by incubating 20 g of nuclear extracts for 30 min at room temperature with 4 mm tris - cl ( ph 7.9 ) , 12 mm hepes , 1 mm dtt , 60 mm kcl , 10% glycerol , 1 mm edta , 2 mg poly(di - dc)-poly(di - dc ) , and 20,000 cpm of the labelled nfb oligonucleotide . the specificity of the dna - protein binding was determined by competition with a 50-fold molar excess of the unlabeled nfb . the dna - protein complexes were electrophoresed for 2 h at 30 ma in a 4% polyacrylamide gel in 0.5% tris - borate - edta running buffer . the gels were dried for 1 h , exposed overnight to imaging plates , and scanned with a phosphoimager ( fla3000 , fuji , dsseldorf , germany ) . ( n = 46/group ) were analysed with ribonuclease protection assay ( rpa ) 4 h after stimulation . for rpa , lungs were flash - frozen in liquid nitrogen and kept at 80c . the tissue was homogenized and total rna was extracted by guanidinium thiocyanate method as described elsewhere . the mrna levels of mmp-1 , -2 , -3 , -8 , -9 , and timps 14 per 20 g rna sample were analysed with mmmp-1 multiprobe template set ( bd biosciences pharmingen , san diego , ca , usa ) . chemokine mrna of lymphotactin , rantes ( regulated on activation and expressed / secreted by t cells ) , macrophage inflammatory protein ( mip)-1 , mip-1 , mip-2 , macrophage chemotactic peptide ( mcp)-1 , t - cell activation protein ( tca)-3 , eotaxin , and interferon - inducible protein ( ip)-10 was detected with mck-5c multiprobe template set ( bd biosciences pharmingen , san diego , ca , usa ) . mrna expression of proinflammatory cytokines il-12p35 , il-12p40 , tnf- , il-1 , il-1 , il-6 , and ifn as well as receptor expression of tlr2 and tlr4 were determined with custom - made template sets ( bd biosciences , heidelberg , germany ) . signals were quantified densitometrically with aida software v3.5 ( raytest , straubenhardt , germany ) and normalized to ribosomal housekeeping gene l32 . tlr1 , -6 , and -9 gene expression ( n = 6/group ) was determined with rt - qpcr 4 h after stimulation . tnf- mrna was monitored with the same technique 0 , 2 , 4 , and 6 h after tlr - ligand application . the taqman gene expression assays ( applied biosystems , foster city ca , usa ) for murine tlr1 ( comm . : tnf- protein expression ( n = 4/group ) was determined with enzyme linked immunosorbent assay ( elisa ; bd biosciences , san jose , ca , usa ) 0 , 2 , 4 , and 6 h after stimulation . for protein isolation , pulmonary tissue was homogenized and incubated on ice for 5 min in 1 ml elisa buffer containing protease inhibitors ( roche , complete mini no . 11836153 ) , pbs , triton x-100 ( 1 l / ml , sigma aldrich , munich , germany ) , phenylmethylsulfonyl - fluoride ( pmsf , 250 mm in isopropanol , 1 l / ml , roche , basel , switzerland ) . samples were incubated on ice for 20 min , homogenized , and centrifuged 15 min at 4c and 13,110 g. the supernatant was used for measuring intrapulmonary tnf- protein levels in a microplate reader ( expert 96 , asys hitech , eugendorf , austria ) . for zymographic activity of pro and active forms of mmp-2 and -9 in lung tissue ( n = 3/group ) , 60 g protein were mixed with 2x tris - glycine sds sample buffer , and loaded on 10% polyacrylamide gels ( sds - page ) copolymerized with gelatin ( each 0.3 mg / ml type a from porcine skin and type b from bovine skin ; sigma aldrich , munich , germany ) . following 90 min of electrophoresis at 125 v , gels were washed with 2.5% triton x-100 ( sigma aldrich ) for 3 20 min to remove sds . afterwards , gels were incubated for 48 h at 37c in developing buffer ( 50 mm tris hcl , 0.2 m nacl , 5 mm cacl2 , 0.02% brij ) . ( sigma aldrich ) in a mixture of water : methanol : acetic acid ( 5 : 5 : 1 v / v ) , destained in 45% methanol , and 3% acetic acid in water ( v / v ) . areas of protease activity were detected as transparent bands against blue background . zymograms were scanned , and signals were quantified using aida software ( aida image analyser , raytest gmbh , straubenhardt , germany ) . for comparison , the zymographic activity of the three virulence factors 4 h after stimulation was normalized to their baseline activity ( 0 h , data not shown ) . after 4 h of tlr ligand stimulation , lungs were taken and flash frozen in liquid nitrogen ( n = 5/group ) . tissue was homogenised on ice in 1 ml of 0.5% hexadecyltrimethyl ammonium bromide ( htab ; h-5882 , sigma ) in 50 mm potassium phosphate buffer ( 1 ml buffer/50 mg tissue ) . 1 ml of the homogenate was transferred into a tube and centrifuged at 5,000 rpm for 4 min . 7 l of the supernatant were mixed with 200 l o - dianisidine solution ( 16,7 mg o - dianisidine ( d-3252 , sigma ) in 90 ml ddh2o , 10 ml 50 mm potassium phosphate buffer , and 50 l 1% h2o2 ) . the change in absorbance with time was continuously recorded at 450 nm using a kinetic microplate reader . one - way anova was used to determine significant differences in mrna - expression ( n = 4 ) , elisa ( n = 4 ) , and zymographic assay ( n = 3 ) between the different stimulation groups . when appropriate , bonferroni post hoc testing was performed . statistics were calculated using prism 5.0 ( graphpad software inc . , san diego , ca , usa ) . to equilibrate the potency of the different applied tlr ligands a tnf activity assay was applied . viability of tnf - sensitive fibroblasts exposed to serum from animals treated by one of the three tlr ligands dropped significantly in all groups ( lta : 57 13.7% , lps : 40 2.4% , cpg - odn : 42 5.1% ; p < .05 versus pbs serum control ) 2 h after incubation . hence , nfb transcriptional activation was measured 2 h after stimulation with the three tlr ligands using an emsa . no major visual differences were revealed following lps and cpg - odn stimulation ( figure 1 ) . lta , however , induced a markedly lower nfb activity than the other two ligands . sensitivity of pulmonary tissue to lps , cpg - odn and lta may be regulated by the level of specific tlr expression . therefore , we monitored mrna expression of tlr1 , 2 , 4 , 6 , and 9 4 h after stimulation . lta application resulted in a twofold increase of tlr1 , 2 , and 6 expression but did not reach the level of significance ( figure 2 ) , neither tlr4 nor tlr9 mrna was changed . lps acted more strongly elevating tlr2 and 6 expressions significantly versus control and tlr4 versus lta - treated animals . tnf- has been shown to be an early inflammatory marker , which is often upregulated transiently . therefore , we monitored the time course of pulmonary tnf- mrna expression 0 , 2 , 4 , and 6 h after virulence factor challenge ( table 1 , n = 4/group ) . lps challenge , however , raised mrna expression significantly at all investigated time points . under baseline conditions , 2 h after stimulation , all virulence factors significantly increased tnf- protein expression ( table 1 ) . at the later time points , a significant enhancement of tnf- protein therefore , these mediators were investigated in the lung 4 h after stimulation using rpa ( figure 3 ) . il-1 , tnf- , il-6 , il-12p35 , il-12p40 , and ifn- , whereas cpg - odn only elevated tnf- and il-12p40 mrna . analysis of lungs from lps - treated mice revealed a marked and significant increase in all monitored chemokines ( lymphotactin , rantes , mcp-1 , mip-1 , mip-1 , mip-2 , tca-3 , eotaxin and ip-10 , figure 4 ) as compared to all other groups . however , neither lta nor cpg - odn stimulation caused any significant changes in chemokines . myelop - eroxidase ( mpo ) activity was assayed as a marker of neutrophil infiltration into the lung . mpo activity was increased 9- to 16-fold in all stimulated groups 4 h after tlr ligand application ( figure 5 ) . with a 16-fold induction compared to the control group , this value differed significantly from lta- and cpg - stimulated mice which showed a 9- and 11-fold increase . interestingly , doubling of the standard lta dose did not further raise mpo activity . during inflammation consequently , 4 h after simulation total mmp mrna expression was significantly enhanced by all three virulence factors with the greatest overall stimulus being cpg - odn ( figure 6 ) . lta induced a significant increase in mmp-2 and mmp-9 as well as a 5-fold elevation in mmp-3 and 18-fold elevation in mmp-8 . lps stimulation significantly enhanced mmp-1 , mmp-3 , mmp-8 , and mmp-9 while cpg - odn raised mmp-2 and mmp-8 significantly as well as mmp-1 , mmp-3 , and mmp-9 nonsignificantly . furthermore , lps significantly enhanced timp-1 and -3 expressions whereas lta and cpg - odn did not induce any changes in single timp expressions . interestingly , the unchanged timp-2 expression was relatively high in all groups ( control : 57.78 14.79 ; lta : 57.08 2.63 ; lps : 25.38 1.68 ; cpg - odn : 42.56 2.80 ) compared to timp-1 and -3 . since the stoichiometry between the gene expression of mmps and their physiological antagonist ( timps ) has been shown to be important for the regulation of the extracellular matrix remodelling , we calculated the ratios of mmps to timps ( table 2 ) . due to the up - regulation of the total mmp mrna expression in all stimulated groups , overall mmp / timp ratio was significantly elevated 4-fold by lta , 5-fold by lps , and 8-fold by cpg - odn . to expand the results on mmp and timp mrna expression , accordingly , we detected an induction of mmp-2 and mmp-9 in their precursory ( pro ) and active form ( not shown ) . to compare effects of different virulence factors , we normalized zymographic activity ( 4 h ) to baseline activity ( 0 h ) ( figure 7 ) . cpg - odn challenge significantly increased mmp-2 activity compared to lps and lta application . here with the present study , we characterized differential pulmonary inflammatory responses to various virulence factors . studies comparing the influence of different tlr stimuli on pulmonary tissue were mainly performed in vitro . therefore , we decided to compare lta , lps , and cpg - odn challenge using remote stimulation in vivo to simulate the initiation of sepsis . for characterization of the inflammatory cascade we monitored a variety of endpoints like tlr expression , nfb activation , expression of various cytokines and chemokines , and mpo activity as well as expression of mmp / timps . in the lung , this broad combination of tlr stimuli and endpoints detected in vivo has not yet been performed . to provide comparability of results , we defined equipotent concentrations for lta , lps , and cpg - odn via a tnf activity assay . after stimulation with lps we observed a strong proinflammatory reaction with increased nfb activation , enhanced cytokine and chemokine expression , and a differential response in mmp and timp expression . the equipotent dose of cpg - odn initiated mediator expression to a lesser degree . here , cytokine and chemokine expression remained a multiple below values evoked by lps . interestingly , stimulation with an equipotent dose of lta had a markedly lesser impact on the induction of cytokines and chemokines in lung tissue . significant variations only occurred in tnf- expression , mpo activity , and mmp / timp regulation . in order to understand the differential answers to tlr stimulation better , we investigated the expression of tlr1 , 2 , 4 , 6 , and 9 . lps induced an increased expression of tlr2 , 4 , and 6 whereas cpg - odn elevated solely the tlr6 expression . induction of tlr2 and 4 by lps in pulmonary tissue has already been observed by others . interestingly , pulmonary tlr4 mrna expression did not reveal a strong regulation after lps challenge . in contrast , tlr2 expression was very sensitive to lps , as it was increased more than 10-fold . in this context , it is interesting that also tlr6 is upregulated by lps and cpg - odn challenge , as lta signalling depends on heterodimerization of tlr2 and tlr6 or tlr2 and tlr1 , and cd36 . this up - regulation of tlr2 and tlr6 might sensitize the lung in an ongoing inflammation to gram - positive stimuli . in accordance with our results , it has been shown that bronchial epithelium regulates its sensitivity to recognize microbes by managing tlr expression levels . bronchial epithelial cells could be stimulated in vitro only marginally by gram - positive bacteria bearing known tlr2 ligands or with lta alone while gram - negative bacteria were easily recognized . as mucosal surfaces are prone to contact with pathogenic , as well as nonpathogenic microbes , immune recognition principles have to be tightly regulated to avoid uncontrolled permanent activation . hence , airway epithelium displays a low sensitivity to inhaled gram - positive bacteria whereas gram - negative bacteria , which are rarely found in airways , do easily induce epithelial activation . a strong immune response following a first hit with lps and a moderate induction caused by first hit with lta might be expected in the lung . however , due to the observed up - regulation of tlr2 by gram - negative challenge sensitivity to lta may be elevated during a second hit . cpg - odn - dependent - up - regulation of tlr6 detected here may further support the sensitization to lta during ongoing inflammation . however , significant up - regulation of pulmonary tlr9 expression was not demonstrated here and is in accordance with recent results from our group . cytokine release evoked by tlr stimulation on lung tissue has been investigated in different settings , such as cultured pulmonal cells or by application of tlr ligands to the airway side [ 12 , 14 ] . to our knowledge , this study compares for the first time a challenge with different tlr ligands applied systemically . tnf- taken from the plasma was used to determine equipotent doses of remote stimuli . on the other hand , tnf- mrna and protein were investigated in pulmonary tissue to compare the inflammatory response of the lung from 06 h after stimulation with each tlr - ligand . here , lps led to a significant increase of tnf- mrna and protein at all time points while lta and cpg - odn elevated its expression only at the earliest time point ( 2 h ) . these results confirm the well - known observation that tnf- is an early inflammatory marker . apart from tnf- , lps also induced all other investigated proinflammatory cytokines at 4 h , cpg - odn raised only il12p40 while lta failed to elevate any of the other inflammatory markers . these findings further support the above - mentioned low sensitivity of the lung to gram - positive stimuli , which may be overcome by direct intrapulmonary application [ 28 , 29 ] . we found a significant up - regulation of il-12p40 in vivo in pulmonary tissue by cpg - odn and lps . this transfers the results from albrecht et al . to the in vivo situation , as they demonstrated an induction of il-12p40 mainly by cpg - odn in transfected macrophages and dendritic cells . il-12p40 bridges the gap between innate and adaptive immunity because it is potently regulated in antigen - presenting cells , thereby activating the adaptive t - helper ( th1 ) cells . these immune cells are attracted into the site of inflammation by chemokines . in our study this is in accordance with the observed high mpo activity after tlr4 stimulation , as monocytes and neutrophils attracted by chemokines exclusively release mpo . lps - dependent infiltration of polymorphonuclear neutrophils into pulmonary vasculature , lung interstitium , and alveolar space as well as bronchoalveolar lavage fluid has already been demonstrated by others . in our setting of remote stimulation , cpg - odn , and , this seems to be in contrast to the literature [ 28 , 32 , 33 ] . however , this difference between our results and those of others may be attributed to the diverse mode of administration ( local versus systemical ) . mmps play a decisive role in the repair of the alveolar epithelium during pulmonary inflammation by cleaving components of the extracellular matrix ( ecm ) . however , excessive expression of mmps can also destroy the ecm and initiate further inflammation and changes in pulmonary architecture . mmp-2 and -9 can be produced by various resident cells in the lung or might stem from stimulated immune cells . similar to mmps , the defined role of their inhibitors is also not fully understood in sepsis . some studies indicate that high timp-1 levels are associated with severe forms of the disease and might , therefore , serve as possible prognostic markers of poor survival . despite low mrna levels of cytokines and chemokines in the lta group , mmp-2 and -9 were significantly induced in lung tissue as a sign of inflammatory affection . however , timp-1 expression was low and remained unaffected by lta . a high mmp9/timp1 ratio has been shown to be associated with a less severe progression of different lung diseases [ 3739 ] . timp-3 may act in a similar manner as timp-3-deficient mice were protected from sepsis - induced pulmonary inflammation and remodelling . the present study provides detailed information on inflammatory events in the lung after in vivo challenge with equipotent doses of lta , lps , and cpg - odn in a murine model of sepsis . these different remote stimuli resulted in specific inflammatory responses in pulmonary tissue indicating an organ - specific immune modulation . lta induced the lowest number of inflammatory mediators , which was associated with a mild progression of lung remodelling . as gram - positive bacteria are commonly inhaled , the respective immune response of the lung has to be strictly controlled to avoid autodestructive inflammation . on the other hand , gram - negative bacteria enter the respiratory tract much more rarely , which may explain the stronger inflammatory response to lps in our setting . however , an ongoing infection with gram - negative bacteria might sensitize the lung towards gram - positive stimuli as tlr2 and tlr6 expressions are upregulated by lps . in addition , cpg - odn that induces the inflammatory cascade via tlr9 is released by both gram - positive and gram - negative bacteria . thus , in case of a bacterial sepsis , the inflammatory response in the lung will never be induced by exclusive activation of tlr2 or tlr4 but always by costimulation of tlr9 . our findings indicate that the lung may be more susceptible to systemic inflammation caused by gram - negative stimuli than to one elicited by gram - positive stimulation .

objective . to determine whether systemically administered tlr ligands differentially modulate pulmonary inflammation . methods . equipotent doses of lps ( 20 mg / kg ) , cpg - odn ( 1668-thioat 1 nmol / g ) , or lta ( 15 mg / kg ) were determined via tnf activity assay . c57bl/6 mice were challenged intraperitoneally . pulmonary nfb activation ( 2 h ) and gene expression / activity of key inflammatory mediators ( 4 h ) were monitored . results . all tlr ligands induced nfb . lps increased the expression of tlr2 , 6 , and the cytokines il-1 , tnf- , il-6 , and il-12p35/p40 , cpg - odn raised tlr6 , tnf- , and il12p40 . lta had no effect . additionally , lps increased the chemokines mip-1/ , mip-2 , tca-3 , eotaxin , and ip-10 , while cpg - odn and lta did not . myeloperoxidase activity was highest after lps stimulation . mmp1 , 3 , 8 , and 9 were upregulated by lps , mmp2 , 8 by cpg - odn and mmp2 and 9 by lta . timps were induced only by lps . mmp-2/-9 induction correlated with their zymographic activities . conclusion . pulmonary susceptibility to systemic inflammation was highest after lps , intermediate after cpg - odn , and lowest after lta challenge .

written informed consent was obtained from the patient for publication of this case report and accompanying images . a copy of the written consent is available for review by the editor - in - chief of this journal on request . all authors made substantial contribution to:conception and design of the study , or acquisition of data , or analysis and interpretation of data,drafting the article or revising it critically for important intellectual content,final approval of the version to be submitted . conception and design of the study , or acquisition of data , or analysis and interpretation of data , drafting the article or revising it critically for important intellectual content , final approval of the version to be submitted .

highlightswe report the case of a 84-year - old patient presenting a giant degenerative ruptured aneurysm of the superficial femoral artery . the patient was also operated one year before , for a ruptured aneurysm of the abdominal aorta.this case report is rare , because we described a case of patient with multiple atherosclerotic aneurysms , who present , for the second time , a life threating ruptured aneurysm.our patient presented , two years before , six synchronic aneurysms without evidence of collagen vascular pathology despite a genetic screening .

drawing from anthropology , health technology assessment , science studies , and bioethics , this project is part of a longitudinal ethnography of regulatory practices for emerging health biotechnologies that began in 2000 ( graham 2008 ) . while observing canadian health regulators during the 2006 who biological standardization expert advisory meeting , i met several scientists involved in the mena vaccine development . marc laforce , a seasoned international health physician and director of the meningitis vaccine project ( mvp ) ( jdar et al . 2003 ; tiffay et al . 2015 ) invited me in february 2007 to visit the project headquarters in ferney - voltaire , france . i engaged in daily ethnographic participant - observation , attending meetings , interviewing , and talking with a core group of 15 scientists , clinical trial researchers , technology transfer experts , and policy and communications personnel at the who / path ( program in appropriate technologies in health ) mvp headquarters . in october 2007 , i attended the who african vaccine regulatory forum meeting in ouagadougou , burkina faso , where the mvp was presented to around 50 participants . having experienced a mena epidemic earlier that year , burkina faso officials were receptive to countrywide implementation once the vaccine achieved regulatory pre - authorization , although burkinab health officials , scientists , and clinical researchers seemed less enthusiastic than those at the mvp about the vaccine s potential to control meningitis . i subsequently obtained funding to hold two workshops , in burkina faso ( february 2009 ) and canada ( april 2009 ) , attended by a total of 54 researchers and knowledge users to explore conceptual and methodological issues related to african decision - making frameworks for vaccines . from 2010 to 2014 , i engaged in annual two to three week fieldtrips to burkina . taking an ethnographic approach , the methods of participant - observation , field notes , document analysis , and formal and informal interviews were employed . structured and informal interviews were conducted with 68 clinicians , scientists , government officials , health workers , and community members in the district of nouna and in ouagadougou over those five years . data were scrutinized in search of identifiable patterns , clustered , and sorted until distinct and comprehensive themes were generated . they were used to describe , organize , further explore , and interpret the activities , experiences , and understandings about menafrivac s development and implementation . the african meningitis belt stretches from senegal to ethiopia ( lapeyssonie 1963 ) . meningitis outbreaks typically start in late december when the hot dry harmattan winds generate dust and sand that invade nasopharyngeal mucosa , while cooler nights and the annual pilgrimage to mecca bring people together in small , enclosed areas . rains in may and june mark the end of the dry meningitis season and the beginning of the wet malaria season . in 1996 a particularly devastating epidemic , mostly meningitis group a , killed approximately 25,000 people ( who 1997 ) . the who ( 1999 ) brought together 26 representatives of african ministries of health to a meeting in ouagadougou . as the story is told by mvp , the solution offered at the meeting was to shift their strategy from epidemic response to epidemic preparedness building on menc conjugate vaccine development , who s immunization , vaccines , and biologics department supported a combined mena / c conjugate vaccine . by the late 1990s , however , there was a rising menc infection rate in the united kingdom , with a thousand deaths during the decade . vaccine manufacturers pooled resources for the mena / c conjugate vaccine to develop a monovalent menc vaccine to meet that emergency ( rappuoli 2003 ) . in sub - saharan africa during the same period , 700,000 people were infected by meningitis , 100,000 died , and 20% to 30% of survivors were left with life - long disabilities ( jdar et al . the immunization needs of the united kingdom trumped those of africa mena was not considered a market driver no manufacturer was interested in developing a vaccine for 300 million people too poor to purchase it . who formalized the epidemic meningitis vaccines for africa project to address the inequity ( aguado et al . significantly , no alternatives to address social and economic determinants of poor health were on the table . nonvaccine solutions never made it to the who meeting in burkina faso , one of the world s poorest countries , where female and male literacy is approximately 16% and 36% , respectively ( world bank 2013 ) . with 11 million inhabitants in 1996 ( 18.5 million by 2015 ) from 60 different ethnic groups , almost half the population of burkina faso are younger than 15 years . those younger than 5 years in low income countries have particularly high mortality rates , picked off by opportunistic infections exasperated by malnutrition , lack of clean water , and sanitation ( si 2013 ) . vulnerability to periodic drought and desertification severely affects agricultural activities , population mobility , and the economy . formal health services for the rural population are limited to small health centers staffed by a nurse and midwife . most of the population can not afford medications or the poor quality health care services ( si 2013:18 ) . where people were in need of food , jobs , arable land , education , and health care , conditions that compromise immune systems , jani , and raolkvam stated , [ t]echnological approaches to complex health problems appeal to policy - makers furthest removed from cultural and social practices ( 2013:23 ) . in 2000 , fueled by a feasibility study of existing intellectual property and an economic analysis supporting a mena vaccine , who again convened scientific experts and representatives from african ministries of health to endorse their plan . in 2001 , the bill and melinda gates foundation seeded $ 70 million for technology transfer to the partnership between who and the seattle based path to develop a monovalent mena vaccine as a humanitarian appeal to global inequity in disease response ( jdar et al . the who / path / mvp consortium advanced a strategy to eliminate epidemic meningitis through the development , testing , licensure , and introduction of vaccines . according to an informant , the ceo of path , chris elias , wanted to just get the vaccine and leave though he would nt say that now . previous experience leading a unicef task force , however , had taught the director of mvp that public health strategies depend on technology and development , external donor assistance , politics and government , organizational structure and operations ( unicef 1996:xv ) . community participation , commitment , and mobilization are integral tools in creating an essential demand for vaccines . country capacity building for surveillance , monitoring , communication , and vaccine safety reporting would complement the mvp . a vaccine , however , needed materials and a manufacturer . laforce orchestrated the negotiation of intellectual property rights and business investment models for the technology transfer among a series of public and private actors . while an established vaccine manufacturer was the preferred partner required of gates projects , after almost two years of negotiations during an era of blockbuster pharmaceutical industry profits and despite the humanitarian appeal , the large vaccine companies could not be persuaded ( personal communication ) . ( siil ) , a family - owned biotechnology manufacturer located in pune , was burdened by neither a board nor shareholders . government scientists at the us food and drug administration s center for biologics evaluation and research ( fda - cber ) had already developed a conjugation method . mvp worked with the us national institutes of health to obtain the technology for siil at a very low cost ( personal communication ) . synco bio partners , a biopharmaceutical good manufacturing practice contract manufacturing organization based in the netherlands , supplied the antigen , meningitis a polysaccharide ( mena ps ) , while siil provided the protein tetanus toxoid ( tt ) to which the antigen would be conjugated the binding together of these two materials generates the enhanced immunity of conjugate technology for psa - tt menafrivac . working with leading conjugate vaccine scientists , by 2004 siil had a vaccine for preclinical studies . human clinical safety trials began in 2005 in india ( phase 1 ) , mali , ghana and the gambia ( phase 2 , 2006 - 9 ) , and in mali , senegal and the gambia ( phase 2/3 ) in 2007 . to manage rumors , an integrated communications strategy ensured the active cooperation of stakeholders throughout the clinical trials and introduction ( berlier et al . mvp concentrated primarily on building technical capacity for surveillance at the multi disease surveillance center ( mdsc ) in ouagadougou . as a reference center for surveillance and response , mdsc became a fully equipped microbiology and dna laboratory providing support for 13 sub - saharan african countries ( who 2009 ) . equipped with new in - country capacity and reinforced by seconded staff from the us center for disease control and prevention ( cdc ) , detailed analyzes could be done to evaluate meningitis trends and bacteriology . by april 2007 , the burkina faso ministry of health had reported 22,255 suspected cases of meningitis including 1490 deaths and 34 districts , surpassing epidemic threshold . the intercountry support team ( ist ) was now in a position to support public health salaries , epidemiological surveillance , and laboratory activities across the meningitis belt , and on september 4 , 2008 , health ministers from the belt signed the yaound declaration on elimination of meningococcal meningitis type a epidemics as a public health problem in africa ( who 2008 ) . menafrivac was approved on january 22 , 2010 by the drugs controller general of india , who received regulatory support from health canada . siil scaled up production to more than 300 million doses after the vaccine met who s prequalification procedure for international standards of safety , quality , and efficacy on june 23 , 2010 . who / mvp provided training for national regulatory authorities to fine - tune their strategies for the vaccine s introduction . who / afro and national ministries of health were to be integral to the positioning of the mena vaccine into the expanded program on immunization ( epi ) within five years of its initial introduction , and in tracking activities related to changes in serogroup prevalence and incidence after the vaccine s introduction . gates funding for menafrivac included neither vaccine purchase nor implementation ( more than ten - fold the cost of vaccine development ) . as a result , a network of collaborative capitalist relationships were established to fund the introduction . the global alliance for vaccines and immunization ( gavi ) , established by the gates foundation in 2000 to broker private - public partnerships integral to funding vaccines in poor countries , facilitated the purchase ( gavi 2014 ) . who , unicef , the world bank , and the gates foundation each hold permanent seats on gavi s board . the success of the who / path / mvp siil partnership is without precedent ( laforce and okwo - bele 2011 ; bishai et al . 2011 ; sow et al . , menafrivac was introduced across burkina faso for everyone aged 1 to 29 years . to date , more than 250 million people have been vaccinated across the meningitis belt and meningitis a appears to have been eliminated in immunized regions . the capricious epidemiology of meningitis disease , however , tells a different story , and the degree that menafrivac has resolved meningitis epidemics and succeeded in improving general health systems and economies is not certain . bacterial meningitis is caused by three pathogens , haemophilus influenza , streptococcus pneumoniae , and neisseria meningitides ( nm ) . the monovalent vaccine for neisseria meningitides a ( nma ) tackles only one , albeit the most prominent , of six vaccine preventable subgroups of nm that threaten sub - saharan africa ( men w-135 , y , x , recently c , and potentially b ) . these lurking subgroups represent what mcgoey ( 2012 ) might call strategic unknowns ; their potential to change with the shifting dynamics and epidemiology of a mena - free sub - saharan africa was largely sidelined by mvp during menafrivac development . arriving in burkina faso in september 2007 , i was struck by the skepticism surrounding menafrivac of several west african clinical researchers . their experience with the three pathogens and numerous subtypes of meningitis disease suggested that controlling meningitis would take more than a mena vaccine . while no one denied that the conjugate vaccine would be superior to its polysaccharide predecessors , many regions were already seeing a rise in men w135 and x , as well as streptococcal pneumonia ( djibo et al . mena was already in decline in burkina faso after the 2007 outbreak , and there were other priorities . by 2011 , these clinicians concerns were proving justified . frustrated senegalese public health workers had no appropriate vaccine to treat outbreaks of men w135 during that country s mena vaccine campaign . in chad , the preponderance of serogroup w and a varied between areas , while mena immunization continued ( caugant et al . short duration meningitis outbreaks followed menafrivac immunization in districts of benin , burkina faso and nigeria , necessitating response , heightened surveillance , case management , and sensitization ( delrieux et al . concerns about reliability and partial surveillance challenged mvp s claims of herd immunity based on decreased carriage rates . even in post - implementation success stories , bracketed caution warranted continued monitoring for potential replacement strains ( novak et al . community outbreaks of streptoccoccus pneumonia , men x , w135 , and most recently men c ( funk et al . success stories about controlling a disease can be seductive , partial accounts concealing complicated histories and unpredictable currents of biologies , seasonalities , and shifting pathogenic and serogroup ecologies . such narratives mask failures and ignore the social , political , and institutional exigencies that disrupt science ( clemens and jdar 2005 ) and collaborative capitalist projects alike . in 1980 , halfan mahler , then who s director - general , warned that single - disease projects would divert attention and resources from the structural and economic roots of ill health , and from the commitment to strengthening primary health care critical to success narratives is the setting of achievable goals . at the start , mvp identified an existing ( appropriate ) vaccine technology . in 1983 , conjugate technology had been proven safe , effective , and immunogenic while conferring long - term protection in infants with the development of haemophilus influenza type b ( hib ) vaccine ( hamidi et al . 2014 ) . acknowledgement of what constitutes the success of some programs , however , can meet resistance . cuba s innovative public good approach to vaccine biotechnology , for instance , produced the first meningitis b vaccine in 1985 , and the first affordable synthetic hib vaccine in 2003 ( reid - henry 2010 ; thorsteinsdttir et al . 2004 ) . in much the same manner , fda - cber and cdc contributed publicly owned conjugate technology methods to siil . the fda s publicly funded technology transfer eliminated affordability as the major constraint , and siil , a private company , was guaranteed a 10-year publicly funded market . through gavi support , mvp gained commitments in excess of $ 500 million from charitable , not - for - profit and nongovernment organizations , to help countries purchase and implement menafrivac . strengthening has gained interest , first from who ( 2007 ) , and more recently from the gates foundation with interest in documenting the impact of vaccine interventions on health systems ( hyde et al . 2012 , 2014 ; mounier - jack , griffiths et al . 2014 ; mounier - jack , burchett et al . complex relationships , numerous interventions , and broad outcomes are neither immediately discernible nor easily counted . tallies of mvp success looked only at the vaccine itself . they did not dock points for disrupted routine services ( mounier - jack , burchett et al . 2014 ) nor document the inability of communities to respond to the outbreaks of men w135 , c , and streptococcus pneumonia after the menafrivac campaign . resourcing local clinics to treat the diseases that replaced mena was not in the calculation . who ist workshops held in abidjan and geneva in 2013 aimed instead at technical collection , conservation , and transportation of biologic substances ; and providing training on standard operating procedures for enhanced surveillance of meningitis , data management , and laboratory confirmation work . in the end the overarching goal is to promote standardized laboratory practices and to enhance the information for decision making ( mvp 2013:2 ) . in the shadow of the unicef report that had recommended balancing the technical , political , and cultural uncertainties of public health , a rhetoric of successful technical vaccine innovation inspired by international partnerships trumped the more unwieldy social determinants of health and pathogen subgroup replacement marchal , cavalli , and kegels ( 2009 ) questioned claims made about strengthening health systems in disease - specific initiatives . such programs leave in their wake duplications , imbalances , and interruptions to existing programs . they impose external goals , neglect national priorities , and community training and resource needs ( mills 2005 ; cavalli et al . developed to facilitate investments , the elegance and simplicity of the who ( 2007 ) building blocks approach has contributed to its wide adoption and provided a common language and shared understanding for health systems strengthening ( mounier - jack , griffiths et al . the framework fails , however , to address the complexity between the blocks , or to articulate subtle issues surrounding workforce , governance , and community ( mounier - jack , griffiths et al . the mvp was aware of the role communications and social mobilization perform in creating demand for a vaccine ; these instruments were used to obtain high vaccine coverage rates ( 101% in some communities ) . with success counted as numbers vaccinated and ridding africa of mena , there was no need to build sustainable community engagements , health systems , or address social determinants . it proves particularly challenging with the scarcity of independent appraisers in collaborative capitalist ventures in global health . an international call for open access for independent critical appraisal of clinical trial methodologies and data in recent years raises concerns about such gaming ( british medical journal 2016 ; open trials 2016 ) . undermining claims for the efficacy and safety of health products , evidence grows of institutional corruption that compromises transparency and accountability in clinical research , and in the selection of methodologies used to measure success ( light , lexchin , and darrow 2013 ) . conflicts of interest play a significant role in regulatory decision making ( abraham 1995 ; nik - khah 2014 ; dunn et al . richard rottenburg ( 2009:88 , 177 ) described how attention to externally driven technical facts renders invisible the cultural and political aspects of development . at the country level , disease eradication campaigns distract attention and resources from regular immunization programs and remove essential human resources from primary health care services . producing meaningful metrics to account for people , their relationships , and geographies requires infrastructure and human resources against a backdrop of unrestricted education available equally for all . the year before , at the 1978 alma ata conference , who had advocated for socioeconomic development and community participation in health care . in response , delegates at a rockefeller sponsored bellagio conference in 1979 parsed primary health into measurable selective primary health care targets for malnutrition , oral rehydration , breastfeeding , and immunization . structural adjustment policies by the world bank and international monetary fund from organization of the petroleum exporting countries oil revenues of rich countries were invested in targeted development loans to low income countries . as interest rates shot up in the 1980s , these countries could not afford to repay these loans and the programs floundered . to address resource and supply inequities , the 1987 bamako initiative recommended increasing access to essential medicines to decentralize primary health care decision making to the local level , expecting communities to finance the purchase , delivery , and monitoring of medicines through revenue from sales ( van olmen et al . the united states decreased its financial contributions in protest over who s essential drug programme , which was seen to oppose the pharmaceutical industry : by 1990 , the bank s loans for health surpassed who s total budget initiatives advancing systems approaches , where countries might set their own priorities and where vaccines are but one mechanism to achieve their overall goals , have received relatively short shrift by the international financial consortia that replaced who ( storeng 2014 ) . as marc - andr gagnon ( 2011 ) described the global pharmaceutical industry operating as a cartel , so too these consortia do not adhere to capitalist laws of value creation in a free and open market . economic analyses are offered without access to raw data and the full inventory of health determinants . old and new arguments alike reinforce the claim that vaccines prevent costly disruptions to health delivery and that , administered through regular schedules , they contribute to a healthier economy ( hardon 1990 ; colombini et al . 2011 ) . yet , for a range of reasons a failure to maintain vaccine coverage , an inadequate management or procurement strategy , the lack of food or health care the burden of disease is not reduced . according to rottenburg ( 2009 ) , the determination of variables that go into the calculation of disrupted routine health care or emergency response is a technical game. lwy and zylberman remind us , however , that in another century , [ e]ven rf [ rockefeller foundation ] officers were obliged to acknowledge that poverty generates disease , not the other way round ( 2000:378 ) . in burkina faso , center of calculation ( latour 1987 ) that collected and analyzed technical facts about meningitis disease . while burkinab clinical researchers were optimistic about the lives saved from mena by menafrivac , they called attention to the persistent challenges ( and higher prevalence ) of malaria , respiratory infections , and diarrheal disease . in burkina faso , poor quality , fee for service health infrastructures did not improve , and the inclusion of the monovalent mena vaccine into the routine immunization program sat uneasily with the rising incidence of other vaccine preventable meningitis diseases . with gavi - facilitated financing , the who / path / mvp consortium set technically achievable outcomes with no platform for basic health care . according to muraskin ( 2005:237 ) , for the dedicated cadre that enables the gavi to function , and which constitutes its indispensable human infrastructure , the primacy of immunization is nonnegotiable . using mechanisms that lack transparency , guaranteed markets are negotiated for select vaccine manufacturers , indemnifying them from risk and relegating vaccine development to the largest companies capable of meeting the multilateral approaches absorb all potential actors as collaborators in a common initiative , leaving few detractors to critique claims of success ( light 2009 ) . stories of technical success ignore the distraction of politics and social realities ; they disregard the challenges of international trade agreements that disrupt country markets . local market failures need not be associated with global financial markets in these partial accounts . first , publicly funded resources ( scientists , regulators , public health officials , donors , and citizens ) were captured within an ideology that vaccines are the only solution , and that they must be developed through the private sector as an industrialized science ( blume and geesink 2000 ; blume 2008 ) . and third , it targeted a single disease subgroup across an entire continent despite long - term epidemiological evidence of community outbreaks of different subgroups over time . while mena was the most common , other types existed and would move in where a gap could be found , as burkinab clinical scientists told to me in 2007 . vaccines are transnational commodities developed through multilateral negotiations ( i.e. , product development partnership funding mechanisms ) involving scientists , governments , industry , and their cultural brokers . they are undeniable techno - social - scientific innovations ( lakoff 2005 ; petryna , kleinman , and lakoff 2006 ; petryna 2009 ; closser 2010 ; huzair , borda - rodriguez , and upton 2011 ) . networks of scientists choreograph chemistry , bacteriology , microbiology , and cytology with epidemiological surveillance , disease burden , seroprevalence , and antigen protection to produce vaccines that boost individual and population response to foreign invasion . much persuasion has gone into capturing scientists , regulators , and citizens into believing that vaccines have primacy over health systems and that they must be developed through a private sector . funded by a complicated , not always transparent constellation of suprastate agencies , nations , and donors , vaccines as public health goods are swept up in neoliberal negotiations surrounding trade secrets , patents , intellectual property , and procurement mechanisms . public health authorities continue to battle the derailment of immunization programs without questioning the challenge to public confidence in vaccines from rumors , industry conflicts of interest , deception , and manipulation of evidence ( renne 2006 , leach and fairhead 2007 ; kaler 2009 ; deer 2011 ; godlee , smith , and marcovitch 2011 ; larson and schulz 2015 ) . threatened by public misinformation campaigns , distrust and failing to understand the sources of discontent through legitimate engagement of local community priorities , public health vaccine advocates often forget the principles of scientific skepticism . ( caryn - rabin 2012:d5 ) , even when their concerns gain wider acceptance ( cohen marill 2015 ) . characterized as valuable public goods when polio campaigns and smallpox eradication were seen to serve society , different vaccines in world systems with profound health care inequities can give the appearance of value extraction ( mazzucato 2013 ) . the rent - seeking behaviors and corrosive capture ( carpenter 2013:152172 ) of a flawed free market model sidelines public health services for economic commodities . i have examined ambiguities in the representation and appropriateness of the technology chosen , and shown how mena came to stand metonymically for meningitis in africa . daniel carpenter ( 2013:63 ) posited three markers for evidence of regulatory capture by influential special interest groups , which i suggest correspond to the ambiguous collaborative approach of mvp . an interested public ( african leaders ) were gathered to endorse the who / path / mvp plan three times in this account ( carpenter s first marker ) ; mvp showed action and intent ( second element ) in developing an affordable vaccine and building country surveillance capacity , but only partially completed each task mena did not rid the belt of meningitis , and capacity building for country surveillance was not extended to community surveillance ( graham et al . 2012 ) . finally , the vaccine diverted the public interest ( carpenter s third element ) regarding general health systems strengthening . when no major vaccine manufacturer would produce the vaccine , the mvp consortium provided a push incentive to build siil s capacity for vaccine development . the mvp supported siil in becoming asia s largest vaccine manufacturer , positioned to be a major supplier to the global south . when public private partnerships are essential to develop vaccines for the world s poorest , evidence of their real world effectiveness should be required ( barr 2007 ; atun , bennett , and duran 2008 ; mounier - jack , griffiths et al . real value added innovations in vaccine development and health systems strengthening should do more than de - risk private investment ( mazzucato 2013 ) . while publicly funded organizations lend vital expertise to global health , philanthro - capitalists determine the agenda and specify the goals ( storeng 2014 ; mcgoey 2014 ) . the declining capacity of who in global health policy and governance , along with the weakening of public health as the world bank eschewed policies that advanced a global social contract was criticized by kickbusch and payne ( 2004:1112 ) as a scandal of global health governance that who member states would allow a situation to arise in which private philanthropy , the gates foundation , has more money to spend on global health than the regular budget of their own organization , the world health organization . men b , c , w-135 , x , y , and streptococcus pneumonia have filled the gap created by the control of mena . in ouagadougou , procedural rules required by centers of calculation reduce localized , complex realities ( rottenburg 2009:190 ) which remained in the margin . why they introduced men a when they knew it was already under control in burkina faso , where scientists and clinicians expressed an array of concerns and skepticism surrounding the project although they welcomed the few resources available from the activities surrounding the campaign . as one researcher said , they targeted men a when they knew it was already under control . when you want to appear to control the wind , you wait until the wind is low and already in control . menafrivac s development exemplifies collaborative capitalism that does not quite achieve what should have been the goal better health within a sustainable health system developed through local priorities . in purporting to address north - south health inequities , it embodied free market tenets , priorities from a top down vertical program , and staked claims for intellectual property while guaranteeing a large market for a small return on investment . this project was funded entirely by the canadian institutes of health research through various grants , including north - south workshop for an african decision - making framework for vaccines cihr-88301 ; regulatory challenges to the development of new vaccines : mapping emergent relations between science , evidence and policy crc-99978 , articulating standards : translating the practices of standardizing health technologies cihr ogh-111402 , and my canada research chair in bioethics ( 2002 - 12 ) .

abstractthe primary health care approach advanced at alma ata to address social determinants of health was replaced by selective health care a year later at bellagio . subsequently , immunization was endorsed as a cost - effective technical intervention to combat targeted infectious diseases . multilateral efforts to collaborate on immunization as a universal public health good ambiguously capture the interests of the world s governments as well as private , public , and not - for - profit institutions . global assemblages of scientists , governments , industry and nongovernmental organizations now work in public - private partnerships to develop and make essential vaccines accessible , with vaccines marketed as single fix solutions for global health . drawing from ethnographic fieldwork in france and burkina faso that followed the development , regulation , and implementation of the group a meningococcal conjugate vaccine for sub - saharan africa , in this article i describe events during and after the development of menafrivac . a technological success narrative steeped in collaborative capitalist rhetoric disguises neglected health care systems .

endometrial cancer is one of the most common cancers in female patients . during recent decades the most important reasons for this growth are increased life expectancy and the global obesity epidemic . although the mechanism of endometrial cancer is known , the genetic basis of this disease is not fully understood . murine double minute 2 ( mdm2 ) is one of the most important negative regulators of p53 . this protein can function as an e3 ubiquitin ligase responsible for the ubiquitination and proteolytic degradation of p53 . p53 can lead to cell cycle arrest and apoptosis , and can repair dna damage . many studies have investigated the association between the mdm2 t309 g genotype and endometrial cancer incidence . although a significant association was observed in some studies , a clear linkage between mdm2 t309 g polymorphism and the risk of endometrial cancer has not been established [ 613 ] . hence , a meta - analysis investigating mdm2 t309 g polymorphism and the risk of endometrial cancer was carried out to conclusively establish the role of mdm2 t309 g polymorphism in endometrial cancer . we performed a systematic search in pubmed and web of science databases ( updated october 21 , 2015 ) for all english - language publications using combinations of the following key words : ( endometrial cancer ) and ( murine double minute 2 or mdm2 ) . to obtain as many eligible studies as possible inclusion criteria were : ( a ) estimation of the association between mdm2 t309 g polymorphism and the risk of endometrial cancer ; ( b ) case - control or cohort study ; and ( c ) sufficient original data for calculating an odds ratio ( or ) with its 95% confidence interval ( cis ) . all data were carefully extracted and reviewed from each eligible study independently by 2 investigators , and any potential conflict was resolved by discussion between the 2 reviewers . the information extracted from each study included the following : the first author s name , the publication s year , ethnicity , the number of cases and controls , and genotype distribution . a chi - square test was used to estimate the hardy - weinberg equilibrium ( hwe ) among the control subjects . the risk was evaluated through the recessive model ( polymorphic homozygous versus heterozygotes and homozygotes for the wild - type allele ) . additionally , sensitivity analysis was used to examine the stability of results by omitting each study sequentially or omitting the study without hwe . the pooled or was estimated using the fixed - effects or random - effects models according to heterogeneity . the effect of heterogeneity was also quantified using the i statistic , which ranges between 0% and 100% . when lack of heterogeneity between studies was detected , the mantel - haenszel method in a fixed - effects model was used . in contrast , when heterogeneity between studies was present , the dersimonian and laird method in a random - effects model was used . publication bias was examined by funnel plot method , in which the standard error of log ( or ) of each study was plotted against its log ( or ) . the asymmetry in funnel plot data analyses were performed using the cochrane systematic review software review manager 5.2 and stata 11 . we performed a systematic search in pubmed and web of science databases ( updated october 21 , 2015 ) for all english - language publications using combinations of the following key words : ( endometrial cancer ) and ( murine double minute 2 or mdm2 ) . to obtain as many eligible studies as possible inclusion criteria were : ( a ) estimation of the association between mdm2 t309 g polymorphism and the risk of endometrial cancer ; ( b ) case - control or cohort study ; and ( c ) sufficient original data for calculating an odds ratio ( or ) with its 95% confidence interval ( cis ) . all data were carefully extracted and reviewed from each eligible study independently by 2 investigators , and any potential conflict was resolved by discussion between the 2 reviewers . the information extracted from each study included the following : the first author s name , the publication s year , ethnicity , the number of cases and controls , and genotype distribution . a chi - square test was used to estimate the hardy - weinberg equilibrium ( hwe ) among the control subjects . the risk was evaluated through the recessive model ( polymorphic homozygous versus heterozygotes and homozygotes for the wild - type allele ) . additionally , sensitivity analysis was used to examine the stability of results by omitting each study sequentially or omitting the study without hwe . the pooled or was estimated using the fixed - effects or random - effects models according to heterogeneity . the effect of heterogeneity was also quantified using the i statistic , which ranges between 0% and 100% . when lack of heterogeneity between studies was detected , the mantel - haenszel method in a fixed - effects model was used . in contrast , when heterogeneity between studies was present , the dersimonian and laird method in a random - effects model was used . publication bias was examined by funnel plot method , in which the standard error of log ( or ) of each study was plotted against its log ( or ) . the asymmetry in funnel plot data analyses were performed using the cochrane systematic review software review manager 5.2 and stata 11 . after searching 44 articles meeting the search criteria , we identified 8 relevant publications ( 9 case - control studies ) , including 2188 cases and 4654 controls , to assess the relationship between mdm2 t309 g polymorphism and endometrial cancer risk ( figure 1 ) . as shown in figure 2 , there was a significant association between mdm2 t309 g polymorphism and endometrial cancer risk in the overall population in the recessive model ( or=1.61 ; 95% ci : 1.192.19 ; p=0.002 ) . however , there was significant between - study heterogeneity ( i=72% ) ; therefore , we performed sensitive analysis . when the studies without hwe were excluded , the result was still significant ( or=1.70 ; 95% ci : 1.202.42 ; p=0.003 ; i=76% ) . when the study was excluded once , we found that the study by zajac might be the main resource of heterogeneity . when this study was omitted , the heterogeneity decreased ( i=29% ) . in the subgroup of different ethnic populations , the subgroup analysis showed mdm2 t309 g polymorphism was significantly associated with increased endometrial cancer risk in caucasians ( or=1.75 ; 95% ci : 1.162.63 ; p=0.007 ; i=80% ) , but not in asians . the funnel plots appeared to be symmetrical ( figure 3 ) and egger s test did not reveal any evidence of publication bias ( p>0.05 ) . after searching 44 articles meeting the search criteria , we identified 8 relevant publications ( 9 case - control studies ) , including 2188 cases and 4654 controls , to assess the relationship between mdm2 t309 g polymorphism and endometrial cancer risk ( figure 1 ) . as shown in figure 2 , there was a significant association between mdm2 t309 g polymorphism and endometrial cancer risk in the overall population in the recessive model ( or=1.61 ; 95% ci : 1.192.19 ; p=0.002 ) . however , there was significant between - study heterogeneity ( i=72% ) ; therefore , we performed sensitive analysis . when the studies without hwe were excluded , the result was still significant ( or=1.70 ; 95% ci : 1.202.42 ; p=0.003 ; i=76% ) . when the study was excluded once , we found that the study by zajac might be the main resource of heterogeneity . when this study was omitted , the heterogeneity decreased ( i=29% ) . in the subgroup of different ethnic populations , the subgroup analysis showed mdm2 t309 g polymorphism was significantly associated with increased endometrial cancer risk in caucasians ( or=1.75 ; 95% ci : 1.162.63 ; p=0.007 ; i=80% ) , but not in asians . the funnel plots appeared to be symmetrical ( figure 3 ) and egger s test did not reveal any evidence of publication bias ( p>0.05 ) . the present meta - analysis consists of an evaluation of mdm2 t309 g polymorphism and endometrial cancer risk . our results show a significant association between mdm2 t309 g polymorphism and endometrial cancer risk . additionally , after the population was stratified by ethnicity , an increased risk for endometrial cancer was observed in caucasians . mdm2 was discovered in a locus amplified on double minute chromosomes in a tumorigenic mouse cell line . this progress can attenuate p53 function ; therefore , it can increase cancer risk . additionally , mdm2 might play a critical role in cancer progression . in tumor cells , firstly , our results were based on unadjusted single - factor estimates , but if detailed individual information on age , sex , family history , and environmental factors were available , more precise analyses could have been conducted . secondly , because we only searched for articles with sufficient original data and published in english , some inevitable bias might occur in our results , although the funnel plot and egger s test showed no obvious publication bias . thirdly , this meta - analysis contained a relatively small sample size , and deficient control populations , and the limitation of clinicopathological data may have especially affected our final conclusion . our meta - analysis provides evidence that mdm2 t309 g polymorphism is associated with endometrial cancer , especially in caucasians .

backgroundendometrial cancer is one of the most common cancers in female patients . many studies have investigated the association between the mdm2 t309 g genotype and endometrial cancer incidence , but the results have been inconclusive.material/methodswe performed a systematic search in pubmed and web of science databases ( update until october 21 , 2015 ) for all english - language publications . the associations are indicated as pooled odds ratio ( or ) and 95% confidence intervals ( ci).resultswe identified 8 relevant publications ( 9 case - control studies ) , including 2188 cases and 4654 controls , that assessed the relationship between mdm2 t309 g polymorphism and endometrial cancer risk . there was a significant association between mdm2 t309 g polymorphism and endometrial cancer risk in the overall population in the recessive model ( or=1.61 ; 95% ci : 1.192.19 ; p=0.002 ) . in the subgroup of different ethnic populations , the subgroup analysis showed mdm2 t309 g polymorphism was significantly associated with increased endometrial cancer risk in caucasians ( or=1.75 ; 95% ci : 1.162.63 ; p=0.007 ) . no similar result was found in asians.conclusionsour meta - analysis provides evidence that mdm2 t309 g polymorphism is associated with endometrial cancer , especially in caucasians .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Budgeting for Opioid Addiction Treatment Act''. SEC. 2. STEWARDSHIP FEE ON OPIOID PAIN RELIEVERS. (a) In General.--Subchapter E of chapter 32 of the Internal Revenue Code of 1986 is amended by adding at the end the following new section: ``SEC. 4192. OPIOID PAIN RELIEVERS. ``(a) In General.--There is hereby imposed on the sale of any active opioid by the manufacturer, producer, or importer a fee equal to 1 cent per milligram so sold. ``(b) Active Opioid.--For purposes of this section-- ``(1) In general.--The term `active opioid' means any controlled substance (as defined in section 102 of the Controlled Substances Act, as in effect on the date of the enactment of this section) which is opium, an opiate, or any derivative thereof. ``(2) Exclusion for certain prescription medications.--Such term shall not include any prescribed drug which is used exclusively for the treatment of opioid addiction as part of a medically assisted treatment effort. ``(3) Exclusion of other ingredients.--In the case of a product that includes an active opioid and another ingredient, subsection (a) shall apply only to the portion of such product that is an active opioid.''. (b) Clerical Amendments.-- (1) The heading of subchapter E of chapter 32 of the Internal Revenue Code of 1986 is amended by striking ``Medical Devices'' and inserting ``Other Medical Products''. (2) The table of subchapters for chapter 32 of such Code is amended by striking the item relating to subchapter E and inserting the following new item: ``subchapter e. other medical products''. (3) The table of sections for subchapter E of chapter 32 of such Code is amended by adding at the end the following new item: ``Sec. 4192. Opioid pain relievers.''. (c) Effective Date.--The amendments made by this section shall apply to sales on or after the date that is 1 year after the date of the enactment of this Act. (d) Rebate or Discount Program for Certain Cancer and Hospice Patients.-- (1) In general.--The Secretary of Health and Human Services, in consultation with patient advocacy groups and other relevant stakeholders as determined by such Secretary, shall establish a mechanism by which-- (A) any amount paid by an eligible patient in connection with the stewardship fee under section 4192 of the Internal Revenue Code of 1986 (as added by this section) shall be rebated to such patient in as timely a manner as possible, or (B) amounts paid by an eligible patient for active opioids (as defined in section 4192(b) of such Code) are discounted at time of payment or purchase to ensure that such patient does not pay any amount attributable to such fee, with as little burden on the patient as possible. The Secretary shall choose whichever of the options described in subparagraph (A) or (B) is, in the Secretary's determination, most effective and efficient in ensuring eligible patients face no economic burden from such fee. (2) Eligible patient.--For purposes of this section, the term ``eligible patient'' means-- (A) a patient for whom any active opioid (as so defined) is prescribed to treat pain relating to cancer or cancer treatment; (B) a patient participating in hospice care; and (C) in the case of the death or incapacity of a patient described in subparagraph (A) or (B) or any similar situation as determined by the Secretary of Health and Human Services, the appropriate family member, medical proxy, or similar representative or the estate of such patient. SEC. 3. BLOCK GRANTS FOR PREVENTION AND TREATMENT OF SUBSTANCE ABUSE. (a) Grants to States.--Section 1921(b) of the Public Health Service Act (42 U.S.C. 300x-21(b)) is amended by inserting ``, and, as applicable, for carrying out section 1923A'' before the period. (b) Nonapplicability of Prevention Program Provision.--Section 1922(a)(1) of the Public Health Service Act (42 U.S.C. 300x-22(a)(1)) is amended by inserting ``except with respect to amounts made available as described in section 1923A,'' before ``will expend''. (c) Opioid Treatment Programs.--Subpart II of part B of title XIX of the Public Health Service Act (42 U.S.C. 300x-21 et seq.) is amended by inserting after section 1923 the following: ``SEC. 1923A. ADDITIONAL SUBSTANCE ABUSE TREATMENT PROGRAMS. ``A funding agreement for a grant under section 1921 is that the State involved shall provide that any amounts made available by any increase in revenues to the Treasury in the previous fiscal year resulting from the enactment of section 4192 of the Internal Revenue Code of 1986, reduced by any amounts rebated or discounted under section 2(d) of the Budgeting for Opioid Addiction Treatment Act (as described in section 1933(a)(1)(B)(i)) be used exclusively for substance abuse (including opioid abuse) treatment efforts in the State, including-- ``(1) treatment programs-- ``(A) establishing new addiction treatment facilities, residential and outpatient, including covering capital costs; ``(B) establishing sober living facilities; ``(C) recruiting and increasing reimbursement for certified mental health providers providing substance abuse treatment in medically underserved communities or communities with high rates of prescription drug abuse; ``(D) expanding access to long-term, residential treatment programs for opioid addicts (including 30-, 60-, and 90-day programs); ``(E) establishing or operating support programs that offer employment services, housing, and other support services to help recovering addicts transition back into society; ``(F) establishing or operating housing for children whose parents are participating in substance abuse treatment programs, including capital costs; ``(G) establishing or operating facilities to provide care for babies born with neonatal abstinence syndrome, including capital costs; and ``(H) other treatment programs, as the Secretary determines appropriate; and ``(2) recruitment and training of substance use disorder professionals to work in rural and medically underserved communities.''. (d) Additional Funding.--Section 1933(a)(1)(B)(i) of the Public Health Service Act (42 U.S.C. 300x-33(a)(1)(B)(i)) is amended by inserting ``, plus any increase in revenues to the Treasury in the previous fiscal year resulting from the enactment of section 4192 of the Internal Revenue Code of 1986, reduced by any amounts rebated or discounted under section 2(d) of the Budgeting for Opioid Addiction Treatment Act'' before the period. SEC. 4. REPORT. Not later than 2 years after the date described in section 2(c), the Secretary of Health and Human Services shall submit to Congress a report on the impact of the amendments made by sections 2 and 3 on-- (1) the retail cost of active opioids (as defined in section 4192 of the Internal Revenue Code of 1986, as added by section 2); (2) patient access to such opioids, particularly cancer and hospice patients, including the effect of the discount or rebate on such opioids for cancer and hospice patients under section 2(d); (3) how the increase in revenue to the Treasury resulting from the enactment of section 4192 of the Internal Revenue Code of 1986 is used to improve substance abuse treatment efforts in accordance with section 1923A of the Public Health Service Act (as added by section 3); and (4) suggestions for improving-- (A) access to opioids for cancer and hospice patients; and (B) substance abuse treatment efforts under such section 1923A.

Budgeting for Opioid Addiction Treatment Act This bill amends the Internal Revenue Code, with respect to excise taxes on manufacturers, to impose a one cent per milligram fee on the sale of active opioids by the manufacturer, producer, or importer. The fee excludes prescription drugs used exclusively for the treatment of opioid addiction as part of a medically assisted treatment effort. The Department of Health and Human Services (HHS) must establish a program to provide rebates or discounts to cancer and hospice patients to ensure that they do not pay the fee. The bill amends the Public Health Service Act to require any increase in federal revenues from the fee after rebates and discounts are subtracted to be distributed to states under the Substance Abuse Prevention and Treatment Block Grant program. The states must use the funds exclusively for substance abuse (including opioid abuse) efforts in the states, including: (1) specified treatment programs, and (2) the recruitment and training of substance use disorder professionals to work in rural and medically underserved communities. HHS must report to Congress on the impact of this bill on the retail cost of opioids and patient access to opioid medication, the effectiveness of the discount or rebate for cancer and hospice patients, how the funds are being used to improve substance abuse treatment efforts, and suggestions for improving access to opioids for cancer and hospice patients and substance abuse treatment efforts.

Skip Ad Ad Loading... x Embed x Share Lochte and three U.S. swimmers said they were robbed at gunpoint early Sunday, with Lochte saying their cab was pulled over by men impersonating police officers. U.S. Olympic swimmers Gunnar Bentz (R) and Jack Conger are mobbed by the media and onlookers while leaving the police station after questioning in Rio de Janiero. (Photo: Chris McGrath/Getty) RIO DE JANEIRO — A day after leaving Brazil, American swimmer Gunnar Bentz offered an apology for his role in a late-night incident that drew international attention after teammate Ryan Lochte claimed they had been robbed at gunpoint and local police called that a fabrication. But Bentz also said surveillance videos from the gas station where the incident occurred appear to be missing camera angles and scenes that support the four U.S. swimmers' accounts. And he supported Lochte's account that money was demanded from the swimmers at gunpoint before they were allowed to leave. In a statement released by the University of Georgia, where Bentz is a junior, he provided details of the account he gave Rio police after he and teammate Jack Conger were pulled off a plane on Wednesday and prevented from leaving the country. Bentz' version largely supports what Lochte has asserted about the swimmers being in a cab that was approached by armed men who flashed a badge and pointed guns at them, but his statement also rejected Lochte's initial version. And Bentz was critical of Lochte, who Bentz said got into a “heated verbal exchange” with security guards. “Without question, I am taking away a valuable life lesson from this situation,” Bentz wrote in a statement where he apologized to the U.S. Olympic Committee, USA Swimming, Team USA athletes and the university. “In everything I do, I am representing my family, my country and my school,” he said. “I will not take that responsibility lightly.” In his statement, Bentz admits the swimmers, who had been drinking at a party and were on their way back to the Olympic Village, stopped at a gas station to use the restroom but instead relieved themselves behind the building. Bentz said Lochte was the one who “pulled to the ground a framed metal advertisement that was loosely anchored to the brick wall.” Vandalism denied Bentz said he did not see anyone trash the restroom at the station, or even enter it. Fernando Veloso, Rio's chief of police, had said the swimmers vandalized the station's restroom – allegedly breaking open the door, causing damage to a mirror and ripping a soap dispenser off the wall. "There was a locked door out back and I did not witness anyone breaking it open," Bentz said. Bentz said there was no damage to the restroom to the best of his knowledge. Video shot by USA TODAY Sports of the bathroom on Thursday found the bathroom intact — the soap dispenser hung on the wall and the mirror was not damaged. Skip Ad Ad Loading... x Embed x Share Raw security footage shows the U.S. swimmers at the gas station the night of the now debunked robbery. USA TODAY After the four men had returned to the vehicle, according to Bentz’s account, two men approached the vehicle and told them to get out. As Conger and Jimmy Feigen walked away, a security guard held up his badge and drew his handgun, Bentz said. Bentz said he called his teammates back, and a second guard pointed his gun at the swimmers. "Again, I cannot speak to his actions, but Ryan stood up and began to yell at the guards,” Bentz said. “After Jack and I both tugged at him in an attempt to get him to sit back down, Ryan and the security guards had a heated verbal exchange, but no physical contact was made.” Bentz’s statement aligned with that of a witness, Fernando Deluz, a disc jockey who told the Globo television network that he became an impromptu translator. Deluz said the only discussions between the swimmers and the guards were about minor damage — the sign that was knocked off a wall. Bentz said through an interpreter, one of the guards holding a gun on them demanded that the swimmers pay for knocking the sign down to be allowed to leave. He said he gave them $20 and Feigen gave them 100 Reals, which is about $33. “They lowered the guns and I used hand gestures to ask if it was okay to leave and they said yes,” he said. Incomplete videos Bentz stressed that he was never a suspect in the matter and that he has not made any false statements to Rio authorities. Bentz’s account refutes Lochte’s original story that the taxi the swimmers were riding in was pulled over. But it closely matches the version Lochte gave on Wednesday to NBC's Matt Lauer, as it appears on the video that the guards did stop the cabbie from pulling away. Lochte said when the cabbie refused to go and the armed men approached the car, he thought they were being robbed, Lauer said . Bentz’s statement also refutes one by Veloso that two women were with the swimmers. Bentz said the swimmers and driver were the only ones in the cab. Bentz also questioned whether the videos released so far show a complete account of what happened. “Videos of this situation have been emerging the last several days” he said. “However, I am confident that some video angles have not been shown that would further substantiate my account. I also believe some scenes have been skipped over.” PHOTOS: Every U.S. medal won at Rio Olympics ||||| (CNN) The following is a statement from U.S. Olympic swimmer Gunnar Bentz released by the University of Georgia on Friday. (Bentz's statement was released hours after fellow Olympian Ryan Lochte apologized for his behavior over the weekend at a Rio de Janeiro gas station.) "I want to offer a sincere apology to the United States Olympic Committee, USA Swimming, the extraordinary women and men of Team USA, and the University of Georgia. Being a member of the Olympic Swimming Team was an honor and a dream come true. The accomplishments of my teammates were awe-inspiring and I'm so pleased I got to see them up close. I regret this situation has drawn attention away from the Olympics, which have been hosted so incredibly well by Brazil and its citizens. "While I am anxious to put this matter behind me and rejoin my Georgia teammates in classes, practices and competitions, I feel compelled to stress several key points. 1. I was never a suspect in the case from the beginning (Brazilian law enforcement officials saw me only as a witness). 2. I never made a false statement to anyone at any time. "I also want to be forthright about the details of what transpired last Sunday. What follows is consistent with the account I gave to the Brazilian authorities when I was interviewed for the first and only time on Thursday in Rio de Janeiro: "After attending an event with several swimmers from different nations, I left in a taxicab along with U.S. swimmers Jack Conger, Jimmy Feigen and Ryan Lochte around 6 a.m. On the way back to the Olympic Village, we pulled into a convenience store to use the restroom. There was no restroom inside, so we foolishly relieved ourselves on the backside of the building behind some bushes. There was a locked door out back and I did not witness anyone breaking it open. I am unsure why, but while we were in that area, Ryan pulled to the ground a framed metal advertisement that was loosely anchored to the brick wall. I then suggested to everyone that we needed to leave the area and we returned to the taxi. "Two men, whom I believe to have been security guards, then instructed us to exit the vehicle. No guns were drawn during this exchange, but we did see a gun tucked into one of the guard's waistband. As Jimmy and Jack were walking away from the vehicle, the first security guard held up a badge to me and drew his handgun. I yelled to them to come back toward us and they complied. Then the second guard drew his weapon and both guards pointed their guns at us and yelled at us to sit on a nearby sidewalk. "Again, I cannot speak to his actions, but Ryan stood up and began to yell at the guards. After Jack and I both tugged at him in an attempt to get him to sit back down, Ryan and the security guards had a heated verbal exchange, but no physical contact was made. "A man that I believe to be a customer approached us and offered to help as he spoke both English and Portuguese. Understandably, we were frightened and confused during this time. Through the interpreter, one of the guards said that we needed to pay them in order to leave. I gave them what I had in my wallet, which was a $20 bill, and Jimmy gave them 100 Reals, which is about $50 in total. They lowered the guns and I used hand gestures to ask if it was okay to leave and they said yes. We walked about a block down the street and hailed another taxi to return to the Village. "Videos of this situation have been emerging the last several days. However, I am confident that some video angles have not been shown that would further substantiate my account. I also believe some scenes have been skipped over. Additionally, I would like to stress that our original taxi was not pulled over; the only occupants of the taxi were the four of us and the driver; and to my knowledge, there was no damage done to the door or the inside of the restroom. "I am so thankful for the love and support of my family, my friends and my teammates during this time. Without question, I am taking away a valuable life lesson from this situation. In everything I do, I am representing my family, my country and my school. I will not take that responsibility lightly."

– One of the other swimmers caught up in the Ryan Lochte Rio mess has apologized for the controversy, while suggesting that Lochte made things worse during the incident by being hot-headed. “Without question, I am taking away a valuable life lesson from this situation,” wrote Gunnar Bentz, per USA Today. “In everything I do, I am representing my family, my country and my school. I will not take that responsibility lightly.” Bentz provided his version of what happened, and he said video released by Brazilian authorities seems to have been edited to make the Americans look worse than they were. "I am confident that some video angles have not been shown that would further substantiate my account," said Bentz. "I also believe some scenes have been skipped over.” Based on Bentz's account and other reporting, including in the New York Times, here is the latest, and most definitive explanation of what happened: Bentz, Lochte, Jack Conger, and Jimmy Feigen were in a taxi returning from a party, intoxicated, when they stopped at a gas station. They urinated behind the building, where Lochte pulled a metal advertisement from the wall. Bentz says he saw no one enter the bathroom, let alone trash it, as Brazilian police have said. They returned to their vehicle, but two security guards ordered them out and on the ground. Both guards eventually pulled their guns. "I cannot speak to his actions, but Ryan stood up and began to yell at the guards,” Bentz wrote. “After Jack and I both tugged at him in an attempt to get him to sit back down, Ryan and the security guards had a heated verbal exchange, but no physical contact was made.” A passerby stopped to interpret, and the swimmers paid $50 for the damage before leaving. Lochte presented an altered version, and he has apologized, too.

bamboo is a giant grass , with remarkable mechanical characteristics . @xcite or 16.1 @xmath1 @xcitehave been reported in the literature ] nonetheless , as it is a natural material , its drying requires special care in order to prevent the cracking due to dessication @xcite . in some aspects bamboo drying is similar to wood drying : there is a first fast drying stage , in which free water is removed from the plant ; followed by a slow stage in which bond water , from within the cell walls , has to be removed @xcite . the main difference between drying this two natural materials comes from the structure of their tissues . unlike wood , bamboo has a special direction , the culm , along which different tissues are aligned : its fibers , conductive material and parenchymatous tissues @xcite . very few research groups have studied the relationship between shrinkage and fracturing in bamboos . overall shrinkage of bamboo canes can be attributed to the shrinkage of the fiber - phloem bundles , as well as to the shrinkage of parenchyma tissue . in the latter , the collapse of cells can be an important factor . obataya et . al . have shown how the slow drying process can lead to the collapse of _ arundo donax _ cane , @xcite . those authors claim that an slow drying schedule increases the intensity of collapse . on a more general fracture case , habibi and lu have studied the path followed by different cracks within the bamboo culm , by means of micro indentation experiments as well as tensile tests @xcite . interestingly , the micro crack grows mainly in the interface between the parenchyma cells . when the crack reaches a fiber it is sometimes possible for it to continue within the fiber , again in the interfaces between fiber cells . they have also shown how the voids within the bamboo have an effect of crack grow deflection and crack tip energy absorption . i would expect a different path of growth for dessication induced fractures compared to indentation ; as drying stresses are more homogeneous , not having a unique defined direction of deformation . my attempts to look for the fracture in the surface proved futile ; which may be caused by fractures being smaller than the resolution of my optical microscope , or by them being inside of the samples themselves @xcite . then , the problem calls for a different way to characterize the fracture evolution during drying , so i turned the research focus into acoustic emission . as fractures are created at every scale , some of the energy is released in the form of an acoustic wave . in the present letter i have characterized the dessication induced fractures in bamboo _ phyllostachys pubescens_. to do so , i performed drying experiments in which i recorded the acoustic signal produced by the sample . since it was not subject to any other strain , it is safe to assume that the sounds are generated by the dessication induced strains . the goal of this measurement is to obtain information about the drying induced fractures . the hypothesis being that the average shapes of fractures , the distributions of energy released in an avalanche event , and also the waiting times between avalanches ; all have useful information about the process of the drying induced fracturing . the organization of the paper is as follows . in section 2 i describe the experiments , materials and methods used . in section 3 i will present my results and conclusions . two kinds of experiments were performed , namely , on characterizing the process of drying and on characterizing the acoustic emissions . for the former i measured the weight as a function of drying time . for the latter , i measured the acoustic emission resulting from the drying process . ._phyllostachys pubescens _ inter - node samples used in the present study . [ cols="<,<,<",options="header " , ] bamboo samples were prepared from a 4 year old culm _ phyllostachys pubescens _ , harvested on june 2011 , from friedrich eberts plantation in chiavari , italy . three sets of inter - node cut samples were labeled and prepared , as shown in the table . on sample @xmath2 , i performed drying experiments aimed to characterize the likelihood of collapse and fracture . on sample 1 , i took the weight measurements during drying , in order to characterize the speed of drying . finally , on sample 2 , i measured the acoustic emission of breaking events during drying . between measurements the samples were kept on a climate controlled room , with relative humidity of 80% , to minimize the amount of drying happening before the oven treatment . i performed the drying experiments using a salvislab pantatherm d oven . two sets of experiments were performed . first , for the characterization of the speed of drying , @xmath3 inter - nodal bamboo samples of @xmath4 @xmath5 width were dried in the oven at a set temperature of @xmath6 @xmath7 . in this experiment the percentage of weight loss of the bamboo samples as function of time was monitored ; and later averaged to build the plot . the second set of experiments characterized the intensity of the microscopic cracks by measuring their acoustic emission during drying . the drying temperature was again @xmath6 @xmath7 , and the digitization was performed using a standard condenser microphone and a digital sound card at a rate of 9600 bps . the voltage on the microphone is proportional to the energy released as acoustic waves . after the recording , the whole data set was screened to check for noise coming not from the drying specimen . the recording took place during the first 3 hours of drying . background noise , both acoustic and from the electronics , was filtered by means of setting a minimum threshold for recording a voltage signal ( see fig . [ fig : voltagesample ] ) . experiments were performed overnight , to reduce the amount of noise from the environment . later on , the recordings were split in @xmath8 @xmath9 samples ; i listened to each one of them in order to exclude the sections of the recording that presented strong noises , probably arising from the oven . finally , the signals were converted in text files . now , i claim that the continuous acoustic emission events can be interpreted as produced by the breaking of bamboo structures ; be them fibers , conductive materials or parenchyma . therefore they are be called indistinctly crack events or acoustic events . a single event is defined as a continuous signal that lies above the minimum recording threshold . since my objective is the characterization of the fracture process , the exact relationship between the voltage measured by the microphone and the amplitude of the original sound wave in @xmath10 does not need to be explicitly known . moreover , this calibration is a quite complex process , that involves the electronics of the sound card and the software of the computer used to the recording ( os x , a proprietary and closed source operating system by apple inc . ) . therefore i will report my experiments in arbitrary units of amplitude : @xmath11 , and its square is in arbitrary units of energy , @xmath12 . the average of the weight of the bamboo samples as function of drying time is shown in fig . [ fig : dryingtimes ] . let me focus first on the black dots . it seems like there is a linear trend in the semi - log graph for the first three hours of drying . this can be related to a rate process , which can be the removal of the free water ( filling the interior of the cells , not chemically bounded ) . this is followed by a slowest drying phase , between hours three and eight . this may be due to the removal of the bound water ( from inside the cell walls , chemically bounded ) . the thicker samples ( red diamonds ) only show the first stage , but the moisture content has not fallen below 2% , so there is still bond water in the sample . the study of fracture phenomena can be tackled from different disciplines . from the point of view of critical phenomena and statistical mechanics , fracture is seen as a series of bursts ; whose size and temporal evolution characterizes the phenomena . recently papanikolau et . al . have taken the barkhausen noise and studied the functional form of the noise emitted by the avalanches @xcite . besides the signal average shape , they present voltage distributions , power spectrums , and distribution of avalanche sizes @xmath13 and durations @xmath14 . their avalanche size histogram shows a power law distribution at small sizes , followed by a tail . in the present case , fig . [ fig : voltagesizedistributions ] shows the probability distribution of the square of the voltage recorded by the microphone , which is proportional to the energy liberated in the fracture . a power law distribution of avalanche sizes is one indicative of scale free behavior , as seen for instance in the gutenberg - richter law of avalanches , and in the barkhausen noise ; even though the mechanisms that generate the fractures at different scales , there is not a single size of fracture that rules the breaking phenomena . in this case the distribution of the square of the sizes follows a power law ( which is proportional to the energy released in the fracture event ) , @xmath15 with an exponent of @xmath16 . it is interesting to notice that the power law seems to fit for three decades . in the present system small fractures and large ones correspond to different kind of tissues , and can be caused by accumulation or by direct strain ; so it is not at all self evident that the fracture distribution has to be a power law . a second characteristic measurement that can give insight into avalanche processes is the waiting times between avalanches . for earthquakes this distribution is known to follow a unified scaling law , mostly a power - law with a decaying exponential tail @xcite . in the present study , on the contrary , waiting times between avalanches show an exponential decay behavior ; as can be seen in fig . [ fig : experimentalwaitingtimedistribution ] . in this case the time constant is @xmath17 @xmath9 . the difference with the earthquake case can be explained from the fact that in this system the allowed number of cracks is reduced as there are a finite number of elements to crack or delaminate ; while for earthquakes the possible number of rearrangements and fractures is orders of magnitude larger . in this way , this system is closer to the granular materials . in a recent paper , michlmayr and or have studied the relation between the grain - scale mechanical interactions in sheared granular materials and the generated acoustic emission characteristics @xcite . their implementation of a damage accumulation fiber bundle model ( similar to the one by kun et . al ) , shows an exponential decay of the number of events as function of the energy ( their fig . 3 , inset ) ; which is the analogous of the waiting times for that system . to further characterize the structure of the avalanches , i want to know when do the big avalanches occur with respect to the start of the drying process ; as well as whether large energy release indeed means long avalanches . for the former question , to identify the evolution of energy release , the size of the avalanche is averaged over 5 second sound intervals and plotted as function of the number of the sound interval ; and can be seen in fig . [ fig : experimentalvoltageafoclicktime ] . it is possible to identify two stages , early and late , separated by the sound interval number @xmath18 . in the first stage the intensity is a large and decreasing quantity . at the late stage , there is a steady increase of the size of the avalanches as a function of time . the black lines represent the error bars . a possible explanation for the shape of this graph : large values for short times , followed by a steady increase is this : initially , the drying process generates large fractures ; creating free surfaces in a fast process . the presence of this free surfaces hinders the appearance of large cracks . after this follows a second phase , in which further fractures may happen mainly for stress accumulation . this two behaviors are seen in other computational models @xcite . in that previous work , that i did with other collaborators , we shown how the statistics of bursts of breaking events in the case of shrinkage of a thin layer of 2d material could suggest the presence of an underlying critical point . in that case , the two states are related to the way the fracture is created , either by coalescence of micro - cracks or by the appearance of a large isolated crack that spanned the sample . to show the relationship between the size of the avalanches and its duration , i present the correlation between the amount of released energy in an event and its time span in fig . [ fig : experimentalenergyspanscatter ] as an scatter plot . the lower cutoff comes from the imposed threshold of measurement . the discreetness in time span values is a consequence of the sound sampling rate of the acquisition transducer . clearly , there is more dispersion on the crack events that take longer and release a larger amount of energy , while the distribution narrows for shorter times . furthermore it is clear that the relationship between energy release and time span can be fitted to a power law spanning several decades . a final way to characterize the process is to study the average shape of the acoustic emission signal , for different sizes . knowing which shape do small and large avalanches have can be useful to identify the kind of process that generates this fractures . as a matter of fact , in a previous paper @xcite showed a temporal average avalanche shape , rescaled to unit height and duration , has a parabolic shape for small avalanches , that flattens towards a unit pulse shape for longer avalanches ; in the case of barkhausen noise . + to define the intervals that correspond to avalanches of similar size , i performed an histogram of the duration of avalanche events , fig . [ histogramtimes ] . the number of avalanches varies over 4 orders of magnitude . in view of this , i hand picked six intervals : @xmath19,@xmath20,@xmath21,@xmath22 , @xmath23 and @xmath24 . roughly speaking the first three correspond to the most populous bins ( @xmath25 to @xmath26 fractures ) , short avalanches ; and the latter to the large avalanches , more than @xmath27 . [ acoustic - emission ] shows the average avalanche shape for the different bins , as a function of the normalized time span . in the main plot i show the first five averaged signals , with the longest avalanches are shown , but faintly ; while in the inset all the six averaged signals can be seen . unlike the barkhausen effect case from the literature , @xcite in which there is clear symmetry ; in this case most of the signals are not symmetrical : there is a large peak followed by a decay . this can be seen in all intervals but one ( @xmath28 ) . in my view , the asymmetrical shape shape hints for the phenomenon to be that of a single breaking event , and the decay in the signal corresponds to attenuation of the noise . short signals would correspond to small ( or weaker ) elements , as parenchymatous tissue ; while long signals to larger ( or stronger ) elements , as fiber cells . going back to the average signal in the range @xmath28 , the symmetrical shape here would pinpoint to a different mechanism , namely the correlated breaking of similarly sized elements ; a self induced growth process in which a breaking triggers similar events . in terms of the energy , in fig . [ acoustic - emision - square - voltage - semilog ] it can be seen that the average shape of the largest avalanches has a peak of energy dissipation which is almost two orders of magnitude larger than that of the medium and small size avalanches . would be interesting to test whether this is caused by the composite nature of the bamboo , or is rather the result of the dynamics of the avalanche formation ; and would occur also on a more homogeneous material . the experimentally measured acoustic emission signals resulting from drying of bamboo _ phyllostachys pubescens _ shows evidence of free - scale phenomena . firstly , the histogram of experimental squared voltage distributions nicely fit into a power law with exponent of @xmath0 ; while the experimental waiting times do not follow a power law , rather an exponential of slope @xmath29 possibly due to the finite size of the system . secondly , the scatter plot of energy as function of avalanche time span also shows a power law that spans over 4 orders of magnitude . i have also studied the average avalanche shape , and found that both short and large avalanches have an asymmetrical shape with a peak at the beginning . this implies that for those cases there is mainly a single crack event . for medium sized fractures , on the other hand , i have found a more symmetrical shape ; which could be attributed to fracture growth by a self reinforced process . the main question that rests to be answered is whether this behavior is particular to the drying of bamboos ; or can be found in other materials . this can be studied easily from numerical simulations ; which is what i plan to accomplish in the future . this work was funded partly by the `` departamento administrativo de ciencia , tecnologa e innovacin de colombia ( colciencias ) '' ( convocatoria doctorados nacionales 2008 ) and by the computational physics for building materials , from prof . hans herrmann at the institute for building materials , eth - zrich . i want to thank ferenc kun and jos d. munz for helpful ideas and comments . this work could not have been done without the help of miller mendoza , julian schrenk and nuno araujo ; with whom i had enlightening conversations about the system and the measurement process . they also drove me to pick up the bamboo samples from frederic eberts forest in chiavari , italy ( www.bambus.de ) , and transported us back to the eth . eiichi obataya , joseph gril , and bernard thibaut . http://dx.doi.org/10.1007/s10086-003-0578-y[shrinkage of cane ( _ arundo donax _ ) i. irregular shrinkage of green cane due to the collapse of parenchyma cells ] . , 50:295300 , 2004 . 10.1007/s10086 - 003 - 0578-y . yan yu , benhua fei , bo zhang , and xiang yu . http://swst.metapress.com/content/p7h2137254040278[cell-wall mechanical properties of bamboo investigated by in - situ imaging nanoindentation ] . , 39(4):527 535 , october 2007 . linhua zou , helena jin , wei - yang lu , and xiaodong li . http://www.sciencedirect.com / science / article / b6txg-4tyr05h-1/2/ef0811d% 9d8867a3378f5b2aa9ba8759c[nanoscale structural and mechanical characterization of the cell wall of bamboo fibers ] . , 29(4):1375 1379 , 2009 .

i have performed experimental measurements of acoustic emission signals resulting from the drying process of _ phyllostachys pubescens _ bamboo . the emphasis was on identifying individual events , and characterize them according to their time span and energy release . my results show a histogram of experimental squared voltage distributions nicely fit into a power law with exponent of @xmath0 , reminiscent of scale free phenomena . i have also calculated the average signal shape , for different time spans of the system , and found an asymmetrical form . the experimental evidence points to the system having an isolated large crack at the beginning of the simulation .

i express my thanks to s.m . troshin for his help during the work on this paper . i am also grateful to w .- d . nowak , who provided me the formula for estimate of the errors of asymmetry measurement . 99 j. ashman et al . : b328 ( 1989 ) 1 ; b. adeva et al . : phys.lett . b302 ( 1993 ) 533 ; d. adams et al . : b329 ( 1994 ) 399 ; + p. anthony et al . : phys.rev.lett 71 ( 1993 ) 959 . w. wislicki , smc coll . : talk presented at xxix rencontres de moriond , meribel , france , march 1994 ( to be published in proceedings ) . close : an introduction to quarks and partons academic press , london , 1979 . carlitz , j.kaur : phys.rev.lett . 38 ( 1977 ) 673 ; + j. kaur : nucl.phys . b128 ( 1977 ) 219 . gunion : phys . d10 ( 1974 ) 242 ; r. blankenbecler and + s.j . brodsky : phys . d10 ( 1974 ) 2973 . farrar , d.r . jackson : phys.rev.lett . 35 ( 1975 ) 1416 . p. amaudruz et al . : phys.rev.lett . 66 ( 1991 ) 2712 . c. bourelly , j. soffer , f.m . renard , p. taxil : phys.rep . 177 ( 1989 ) 319 ; c. bourelly , j. soffer : nucl . b423 ( 1994 ) 329 ; preprint cpt-95/p.3160 , february 1995 ( to appear in nucl.phys . p.m. nadolsky , in preparation . m. gl " uck , e. reya , a. vogt : z.phys . c53 ( 1992 ) 127 . s. brodsky , m. burkardt , i. schmidt : preprint slac - pub-6087 , january 1994 . nadolsky : z. phys . c63 , ( 1994 ) , 601 .

while emc - smc - e142 data sheds new light on the behavior of polarized parton distributions at small and intermediate @xmath0 , it may be also interesting to study valence quark polarizations at large @xmath0 , where spectator quark counting rules and carlitz - kaur type models predict different behavior for down quark polarizations . the article examines the possibility of testing the ratio @xmath1 at @xmath2 in the inclusive production of @xmath3-bosons . in the last years much attention of hep community is attracted to the physics of polarized hadron interactions , to great extent due to the recent interesting data on polarized inclusive @xcite and semi - inclusive @xcite deep - inelastic scattering . the emc - smc - e142 data already allow to make several conclusions about the nucleon spin structure at @xmath4 and values of bjorken @xmath5 . the analysis of these data in the framework of perturbative qcd provides information on longitudinal polarized parton distributions @xmath6 , interpreted as the differences of probabilities @xmath7 for finding partons of the type @xmath8 with spin parallel / antiparallel to the spin of the parent nucleon . however in the region of @xmath9 the experimental errors have a tendency to grow , while at @xmath10 there is still no data at all . on the other hand , precise studies of various polarized processes at large @xmath0 may provide valuable information about the behavior of longitudinal valence quark polarizations @xmath11 , that are dominant in this region compared to sea quarks and gluons . so far the common opinion on how the polarized quark distributions @xmath12 and @xmath13 should behave at large @xmath0 is not fully established . the experimental information in this region is not precise enough to fix @xmath14 s unambiguously . the theoretical description is also not unique . this problem was examined as far as in mid-70 s , but not solved to the end . since that time the majority of theoretical models , describing valence quarks at @xmath15 , falls into two general categories . the qualitative analysis of the distinctions between these two approaches can be based on the representation of a nucleon as composed from the valence quark carrying a large portion of nucleon s momentum , and a diquark with @xmath16 @xcite ; in good approximation the contribution of the sea may be neglected . the experimental results ( for example , the behavior of the ratio of nucleon structure functions @xmath17 at @xmath2 ) convincingly indicate that the @xmath18-symmetry of the nucleon wavefunction is violated , so that the states containing diquarks with certain spin - isospin numbers @xmath19 are suppressed compared to the situation of the exact @xmath18-symmetry . the models of the first type follow the works of carlitz and kaur @xcite and assume that diquarks in this region must be in a @xmath20 rather than in a @xmath21 state . on the other hand , the models motivated by perturbative qcd start from the assumption that only diquarks in a @xmath22 state are suppressed . one of the pioneering works in the framework of the second approach was published by farrar and jackson @xcite . the different mechanism of @xmath18-breaking in these two approaches leads to different predictions for several quantities measured both in unpolarized and polarized reactions . the most known of them is the ratio @xmath17 , which tends in these models correspondingly to @xmath23 or @xmath24 . most part of the existing data on the structure functions @xmath25 at large @xmath0 evidences in favor of @xmath23 value , providing that perturbative - qcd result is not valid . as for the polarized nucleon interactions , so far no experiment , allowing to discriminate one model from another , was staged on the existing colliders . such an experiment can be based on the fact that carlitz - kaur ( ck ) and farrar - jackson ( fj ) models disagree about the behavior of valence @xmath26-quark polarizations at large @xmath0 . while in ck model @xmath27 , the fj approach predicts that @xmath28 . the information about the limiting behavior of @xmath29 may be obtained in various experiments , for instance , deep - inelastic scattering ; however , it may also be interesting to carry out a straightforward measurement of the ratio @xmath1 . if at least one polarized proton beam is available , one can measure longitudinal single - spin asymmetries @xmath30 in the inclusive production of @xmath31-bosons @xmath32 or @xmath33 ; in the appropriate kinematical range these asymmetries will be directly proportional to the ratio @xmath34 @xcite . in fact , it is not necessary to measure @xmath3-asymmetries in the region of @xmath0 very close to 1 . the behavior of @xmath13 in ck and fj models should be very different already at @xmath35 , where the cross - sections are still noticeable . this paper is dedicated to the discussion of the opportunity to study polarized valence distributions in @xmath3-boson production , especially to the explicit evaluation of the kinematical region , where the event rates will be high enough to make definite conclusions about the magnitude of @xmath1 . but , to begin , let us briefly review the description of valence quark distributions in ck and fj models . since the behavior of parton distributions is determined by the properties of hadrons at large distances , where the running coupling of quark - gluon interactions is not small , the perturbative qcd arguments are not directly relevant to their analysis at arbitrary values of bjorken @xmath0 . however , the situation when the struck parton carries almost all of the nucleon s momentum corresponds to very far off - shell configuration of nucleon constituents @xcite . such a configuration can be obtained from the nucleon state with the lowest orbital momentum and the finite invariant masses of partons only by exchange of hard gluons . in this case the dominant contribution to the amplitude of deep - inelastic scattering is provided by feynman graphs with minimal number of gluon propagators tying quarks into a single hadron . the straightforward calculation of these graphs shows that the falloff of helicity - dependent quark distributions is described by the power - law dependence , @xmath36 where @xmath37 @xmath38 is the minimal number of spectator quarks and @xmath39 for @xmath40 or 1 for @xmath41 . the slowest falloff corresponds to the valence quark distributions , for which @xmath42 . the essential feature of ( [ power ] ) is that the power - law falloff does not depend on the flavor of quarks . therefore the perturbative result prescribes the distributions of valence up and down quarks to be proportional in the limit @xmath2 , and the coefficient of proportionality can be found to be @xmath43 @xcite . it also implies that , independently of quark flavor , the helicity of a quark with @xmath2 must match the helicity of the parent hadron , so that @xmath44 should approach @xmath45 . for valence @xmath26-quarks this means that @xmath13 , which is negative at small and intermediate @xmath0 , the negative @xmath13 was anticipated from theoretical considerations , especially from the sign of its first moment @xmath46 ; these anticipations were recently confirmed by the experimental values of @xmath13 , derived from the analysis of nucleon and deuteron dis data @xcite . ] , must change sign at some @xmath0 , typically chosen to be around @xmath47 . it is necessary to mention that equation ( [ power ] ) provides only upper limit for the magnitudes of quark distributions , which is achieved only if there are no other sources of suppression . meanwhile , there is strong experimental evidence that at large @xmath0 @xmath26-quarks are suppressed compared to @xmath48-quarks . in particular , most part of the experimental information about the ratio of nucleon structure functions @xmath17 , including the most recent nmc data @xcite , shows that it falls lower than the limiting value @xmath24 predicted by perturbative - qcd based approach . the fit of the overall world data on @xmath49 , presented in @xcite , tends to @xmath23 , which is the limiting value for this ratio when @xmath50 falls faster than @xmath51 . such a suppression of valence @xmath26-quarks is an essential feature of another model , proposed by carlitz and kaur @xcite . the valence distributions in this approach are built using simple quark model considerations , especially the assumption that all diquarks with @xmath52 are suppressed relative to those with @xmath20 . the relation @xmath53 , obtained in fj model , should not hold in ck approach , and valence quark distributions can be easily accommodated to satisfy the tendency of @xmath49 to @xmath23 . just as in fj model , @xmath54 as @xmath2 , but the behavior of valence @xmath26-quarks is different and @xmath55 . for typical parameterizations of carlitz - kaur cosines , describing dilution of the valence quark spin in the parton sea and quickly approaching @xmath56 at intermediate and large @xmath0 , @xmath57 is close to its limiting value already at @xmath58 . the latter distinction between fj and ck models ( the retention of valence @xmath26-quark helicity in the first case and @xmath26-quark negative polarization of @xmath59 in the second ) may serve as a basis for one more experimental test of proton inner structure . the inclusive production of @xmath31-bosons in @xmath60- or @xmath61-collisions is very suitable for the investigation of this distinction @xcite . since parity is not conserved in weak interactions , only one polarized initial beam is necessary to get nonzero cross - section asymmetries . thus , one opportunity for this experiment may arise if a polarized proton beam will be put into operation at tevatron . it will be also possible to investigate @xmath31-boson asymmetries in proton - proton interactions at bnl - rhic collider . on the parton level the leading contribution to @xmath31-production is provided by the quark - antiquark annihilation @xmath62 . the analysis of born contribution at small and intermediate values of @xmath31-boson rapidities @xmath63 has already been carried out in @xcite ; however , in this paper i would like to discuss polarized @xmath31-production at large @xmath63 , where the cross - sections quickly fall down , and estimate possible errors of the asymmetry measurement . also , to get reliable estimates of @xmath64-boson cross - sections , one has to consider higher - order contributions ; the discussion of them will be presented elsewhere @xcite . for the reaction @xmath65 the cross - section @xmath66 and the corresponding single - spin asymmetry @xmath30 are written as @xcite @xmath67 and @xmath68 here @xmath69 and @xmath63 are the mass and rapidity of @xmath3-boson , @xmath70 is the fermi constant and @xmath71 the @xmath61 cross - section @xmath72 and asymmetry @xmath30 can be obtained from ( [ cross],[asym ] ) by substituting @xmath73 and @xmath74 correspondingly for @xmath75 and @xmath76 . it can be seen that when @xmath63 tends to upper kinematical bound , @xmath77 , @xmath30 is directly proportional to @xmath78 at @xmath79 . in this limit the other bjorken variable , @xmath80 is of the order @xmath81 for rhic and 0.002 for tevatron . for such @xmath80 s valence quarks become less important compared to the sea , and therefore @xmath82 , @xmath83 . in its turn , this means that @xmath60 and @xmath61 cross - sections , measured at same @xmath84 , at large @xmath63 should be described by approximately the same dependence . however , as shown by numerical results , the cross - sections for typical rhic energies , assumed to be @xmath85 , in the region of most interest are smaller than tevatron ones , calculated for @xmath86 . fig.1 and 2 show unpolarized cross - sections @xmath66 , @xmath72 and corresponding asymmetries @xmath30 as functions of @xmath87 , varying in the interval @xmath88 . these values of @xmath87 correspond to @xmath31-boson rapidities @xmath89 for rhic and @xmath90 for tevatron . the cross - sections were calculated using gl " uck - reya - vogt unpolarized distributions @xcite . 3.5 in fig.1 . differential cross - sections of inclusive @xmath3-boson production in @xmath60-collisions at rhic ( @xmath91 dash line ) and in @xmath61-collisions at tevatron ( @xmath92 solid line ) . 3.5 in fig.2 . single - spin longitudinal asymmetries @xmath30 in inclusive @xmath3-boson production . short dash and solid lines : asymmetries @xmath30 in @xmath60- and @xmath61-channels for bbs model @xcite . long dash and dot - dash lines : asymmetries @xmath30 in @xmath60- and @xmath93-channels for ck - type distributions @xcite as can be seen from fig.1 , both @xmath60- and @xmath61-cross - sections quickly fall down with the increase of @xmath87 , @xmath66 being smaller than @xmath94 . typical values of cross - sections at @xmath95 and @xmath96 are @xmath97 and @xmath98 in @xmath60-channel , @xmath99 and @xmath100 in @xmath61-channel . knowing these cross - sections , it is possible to estimate the statistical error in determination of asymmetry @xmath30 : @xmath101 here @xmath102 is polarization of the beam and @xmath103 is the number of events , expressed as a product of the corresponding cross - section , beam luminosity @xmath104 , pure running time @xmath105 and combined trigger and reconstruction efficiency @xmath106 . assuming that @xmath107 for rhic and @xmath108 for tevatron , @xmath109 ( about 4 months ) , @xmath110 and @xmath111 it is easy to obtain that @xmath112 for rhic and @xmath113 for tevatron . fig.2 shows the asymmetries @xmath30 in @xmath60- and @xmath61-channels both for ck and fj - type polarized distributions , represented correspondingly by set 1 distributions from @xcite and by recently proposed brodsky - burkardt - schmidt ( bbs ) distributions from @xcite is not suppressed and behaves like @xmath114 ; this leads to larger unpolarized cross - sections of @xmath3-production compared to those obtained with standard unpolarized distributions . nevertheless , the conclusions about @xmath30 are influenced only slightly , since @xmath30 practically depends only on the ratio @xmath1 . ] . as expected from the above discussion , already at intermediate @xmath0 the behavior of @xmath30 in ck and fj models is very different : while the former is close to @xmath59 , the latter is around zero and grows . in bbs model @xmath13 changes sign approximately at @xmath115 . it can be seen that even if the zero point is located at larger @xmath0 , e.g. @xmath116 , the precision of the experiment still allows to reliably discriminate one model from another . to conclude , though the problem of the description of helicity - dependent down quark distributions at large @xmath0 is very old and well - known , no direct experimental test of @xmath13 at @xmath2 has been done yet . the study of polarized @xmath31 production at rhic or tevatron colliders may provide important experimental information on the behavior of @xmath1 and help clarify this interesting question .

recently , new data on the analysis of @xmath1 decays were published by two collaborations : kek - e246 @xcite and istra @xcite , in addition to the presentation given by the particle data group @xcite . so , at present we have got quite precise measurements of characteristics in the @xmath2 decays , that needs a theoretical interpretation in the framework of standard model ( sm ) as well as beyond it . such the study is of interest because of the experimental search for effects , which can point to the contributions with the violation of combined cp - parity in the kaon decays , for example , the transverse t - odd polarization of lepton in @xmath3 modes @xcite , that can essentially enrich the information on the cp - breaking dynamics in addition to the program with the b - mesons @xcite . the matrix element of decay is parameterized in terms of scalar , vector and tensor form factors , @xmath4 , @xmath5 and @xmath6 , in the following general form @xcite : @xmath7 = { g_{\rm f } v_{su}}\ , \bigg[- l_\mu \big(f_+ p^\mu + f_- q^\mu\big ) + 2 m_k l_s f_s + { \rm i}\,\frac{f_t}{m_k}\ , l_{\mu\nu } p^\mu q^\nu \bigg ] , \label{me}\ ] ] where the lepton currents are given by the expressions @xmath8 so that chiral spinors are @xmath9 and @xmath10 is the fermi constant , @xmath11 is the mass of kaon . the four - momenta are defined as @xmath12 while @xmath13 is the matrix element of cabibbo kobayashi maskawa matrix for the mixing of weak charged quark - currents . we define the generators @xmath14 by the commutator @xmath15.\ ] ] the dependence of form factors on @xmath16 is usually expressed in terms of linear slopes normalized to get the dimensionless quantities @xmath17 where @xmath18 is the pion mass . the combination of form factors @xmath19 is introduced , so that the experimental data are given in terms of the following set @xcite : @xmath20 the data of @xcite on @xmath21 can be averaged , so that with the statistical errors we get @xmath22 while the systematic uncertainties are given in the original papers . the values in ( [ l+ ] ) and ( [ l0 ] ) result in the ratio @xmath23 the given parameter @xmath24 is in a good agreement with the pdg values for both the electron and muon modes @xcite , while @xmath25 and @xmath26 above are within the limits of 1.5@xmath14-deviations from the pdg averages . the preliminary analysis by ktev @xcite gives @xmath27 which is close to the estimate in ( [ l+ ] ) . in the framework of sm we get the form factors @xmath28 while @xmath29 therefore , the study of scalar and tensor form factors is a good test for the search of ` new ' physics beyond the sm . supposing ( [ v ] ) , we derive @xmath30 implying that the form factor @xmath31 determines the matrix element of scalar quark - current . the contraction of vector lepton - current @xmath32 induces the scalar term in the matrix element . so , the electron mode is more sensitive to the extraction of scalar form factor , since the sm background contribution is suppressed by the lepton mass , @xmath33 at present , the measurements of @xmath4 and @xmath6 result in values slightly deviating from zero , that is consistent with the expectations of sm . so , in the electron mode @xcite @xmath34 where we have taken into account the redefinition of sign in comparison with the appropriate formula in @xcite as accepted in this paper in ( [ me ] ) , while the combined analysis of muon and electron modes in @xcite results in the similar values @xmath35 the collaboration ktev presented the following constraints in the electron mode : @xmath36 in the present paper we study nonzero contribution of leptoquark interactions to the tensor form factor , which correlates with the scalar one due to the fierz transformation . in section 2 the effective lagrangians with the virtual leptoquarks are described as concerns for the decays of @xmath37 , and the requared matrix elements of quark currents are presented . general expressions for the hadronic matrix elements with the tensor structure are derived in section 3 , where we develop the model based on the dominance of vector and scalar mesons and adjust it in the description of @xmath38 form factors . in the framework of potential approach the preferable region of model parameter is limited in agreement with the experimental data . the constraints on the masses of scalar leptoquark and their couplings to the fermions are obtained in section 4 . the results are summarized in the conclusion . a consistent classification of leptoquarks under the gauge symmetries of sm were done by buchmller , rckl and wyler in @xcite . we accept the nomenclature prescribed in @xcite as shown in table [ opal ] extracted from @xcite . so , the leptoquarks are marked by their spin , representation of weak @xmath39-group ( singlets , doublets and triplets ) , appropriate electric charges in the multiplets and the fermion number @xmath40 . for the sake of briefness , the flavor of lepton is marked by the electron in table [ opal ] , while the couplings @xmath41 should be labelled by the flavor indices , too . scalar lq ( @xmath42 ) & charge & @xmath40 & & @xmath43 + & @xmath441/3 & 2 & @xmath45 & @c@ e@xmath46u , + & .the first generation scalar ( s ) leptoquarks / squarks and vector ( v ) leptoquarks in the brw model @xcite according to the nomenclature in @xcite with their electric charge in units of @xmath47 and fermion number @xmath48 . for each possible non - zero coupling @xmath49 the decay modes and the corresponding branching ratio @xmath43 for the decay into an electron and a quark are also listed . the restrictions on the values of @xmath43 arise from the assumption of chiral couplings . [ cols="^ " , ] + v@xmath50 & @xmath445/3 & 0 & @xmath51 : & e@xmath52 & 1 + the diagrams describing the contribution of leptoquark interactions into the form factors under study are shown in fig . [ diag ] . ( 140,50 ) ( 5,1 ) ( 75,1 ) ( 3,0)@xmath53 ( 3,37)@xmath54 ( 65,0)@xmath55 ( 65,37)@xmath56 ( 36.5,18)@xmath57 ( 73,0)@xmath53 ( 73,37)@xmath54 ( 135,0)@xmath56 ( 135,37)@xmath55 ( 106.5,18)@xmath58 the tensor terms appear under the fierz transformations , so that the vector leptoquarks do not contribute into the tensor form factor . further , the tensor term shifts the helicity of leptons . therefore , we isolate the leptoquarks involving the interaction with both the left - handed neutrinos and right - handed charged leptons . the appropriate vertices are shaded in table [ opal ] . thus , we consider the following scalar leptoquarks : the singlet @xmath59 and the doublet @xmath57 with the charge @xmath60 . the yukawa - like interactions involving the strange quark have the form @xmath61 & = & s^*_{1/2}\ , \big({\rm y}_{\rm\scriptscriptstyle l}\ , \bar u_{\rm\scriptscriptstyle r}\nu_{\rm\scriptscriptstyle l } + { \rm y}_{\rm\scriptscriptstyle r}\ , \bar s_{\rm\scriptscriptstyle l } l_{\rm\scriptscriptstyle r}\big ) + { \rm h.c.},\\ { \cal l}[s_{0 } ] & = & s^*_{0}\ , \big[{\rm y}^{[0]}_{\rm\scriptscriptstyle l}\ , ( \bar u_{\rm\scriptscriptstyle c , r}e_{\rm\scriptscriptstyle l}+ \bar s_{\rm\scriptscriptstyle c , r}\nu_{\rm\scriptscriptstyle l})+ { \rm y}^{[0]}_{\rm\scriptscriptstyle r}\ , \bar u_{\rm\scriptscriptstyle c , l } l_{\rm\scriptscriptstyle r}\big ] + { \rm h.c.},\end{aligned}\ ] ] where we have omitted the flavor indices . these lagrangians induce the effective low - energy interactions according to the formulae @xmath62 where we have used the fierz transformations for the chiral fermions , taking into account the identity @xmath63 that causes the summation of scalar and pseudoscalar parts ( the factor of 2 ) . the anti - commutation of fermions has been explored , too ( the overall negative sign ) . further we introduce the notation @xmath64 since the above combination of leptoquark mass and couplings enters the problem under study . as for the contribution of @xmath59 , one can easily find that the effective lagrangian has the same form of ( [ eff ] ) , because the charge conjugation of spinor is defined by @xmath65 where @xmath66 in the dirac representation of @xmath67-matrices , so that @xmath68 where t denotes the transposition . the terms induced by the leptoquarks @xmath57 and @xmath59 can interfere , of course . however , we include this effect into the definition of scale @xmath69 . thus , we can estimate the contribution of leptoquark interactions , once we calculate the appropriate matrix elements of quark currents , that is the deal of next section . the experimental data on the slopes of form factors shown in the introduction are in a good agreement with the estimates in the framework of chiral perturbation theory ( @xmath70pt ) @xcite . however , to the moment we have not any predictions of @xmath70pt on hands as concerns for the hadronic matrix elements of tensor quark - current . in the present paper we explore the model of meson dominance , i.e. the dominance of vector and scalar states appropriate for the quantum numbers of transitions between the quarks . the corresponding diagram is shown in fig . [ domin ] . ( 80,50 ) ( 5,1)=60 ( 0,18.5)@xmath71 ( 55,0)@xmath72 ( 55,37)@xmath73 ( 36.5,23)@xmath74 considering the vector quark - current , we can evaluate the form factors @xmath75 in terms of couplings entering the following lagrangians are prescribed for the charged pions , while the neutral ones have the isospin factor @xmath76 . ] @xmath77 and @xmath78 where @xmath79 denotes the appropriate field , and @xmath80 is the polarization vector of @xmath81 . in ( [ fp ] ) we have introduced the running pole mass @xmath82 in the transition @xmath83 . the normalization condition is rather evident @xmath84 while we need the value at @xmath85 , @xmath86 , since we use the approximation of linear evolution of form factors , @xmath87 the evolution of @xmath82 to @xmath85 is expected to be slow in the framework of model with the meson dominance . we suppose that the spin forces in the bound state should be suppressed beyond the pole , since they depend on a density of bound states , which drops outside the poles . so , the spin - averaged mass of 1s - level in the @xmath88 system is known experimentally , @xmath89 = \frac{1}{4}(m_k+3 m_{k^ * } ) \approx 793\ ; { \rm mev}.\ ] ] we expect that @xmath89 < m_{su}(0 ) < m_{k^*}.\ ] ] so , we put @xmath90 + m_{k^ * } ) \approx 0.85\ ; { \rm gev},\ ] ] which is inside the systematics uncertainty of the model . since the spin - dependent forces are suppressed in the excited p - waves , we put the pole mass in the scalar sector to be equal to the experimental value of @xmath91 . from ( [ lfp ] ) and ( [ lfm ] ) one can easily deduce the expression for the scalar - channel form factor , @xmath92 as well as the slopes , @xmath93 where @xmath94 f_+(0 ) & = & g_{k^*k\pi}\frac{f_{k^*}\ , m_{k^*}}{m^2_{su}}. \label{fp - m}\end{aligned}\ ] ] the most of model parameters can be extracted from the experimental data . so , the coupling constant @xmath95 is well known , @xmath96 while the decay constants @xmath97 are related with the widths measured and @xmath91 we have explored the isospin - symmetry relations : @xmath98=1/2\,\gamma[k^{*+ } \to k^0\pi^+]$ ] and the similar equation for the scalar meson @xmath91 . ] , @xmath99 & = & g_{k^*k\pi}^2 \frac{|{\boldsymbol p}_k|^3}{4\pi m_{k^*}^2},\\ \gamma[k^*_0 \to k\pi ] & = & g_{k^*_0 k\pi}^2 \frac{3\ , |{\boldsymbol p}_k|}{16\pi m_{k^*_0}^2},\end{aligned}\ ] ] whereas @xmath100 denotes the momentum of kaon in the c.m.s , so that numerically$ ] and @xmath101 in the limit of @xmath102 . in the phenomenological model under study , the decay constants @xmath97 enter the form factors in terms of products with the leptonic couplings @xmath103 . these products should be adjusted in order to satisfy some conditions motivated by qcd and its chiral symmetry . in this way we have to follow a specified approach in estimates for both @xmath97 and @xmath103 as given below . we stress that the model parameters @xmath97 are quite uncertain because of reasons inherent for the phenomenological approach ignoring higher excitations as well as a continuum contribution . neverteless , we argue for the preerable choice of numerical values . ] @xmath104 the only free parameter of the model is the coupling @xmath105 , which we are tending to restrict in the framework of potential calculations by the comparative analysis with the known leptonic constants of @xmath106 and @xmath81 . for this purpose , we calculate the diagram in fig . [ pot ] , where the quark - meson vertex includes the wave function of constituent quarks . ( 80,30 ) ( 5,1)=60 ( 55,19)@xmath73 ( 3,23)@xmath107 ( 34,27)@xmath54 ( 35,11)@xmath53 for the scalar state we use the current @xmath108 with the identity @xmath109 = ( m_u - m_s ) j(x).\ ] ] in this technique we find @xmath110 f_{k^*}^{\rm\scriptscriptstyle pm } & = & \sqrt{\frac{3 } { \pi m_{\bar s u}[1s]}}\ ; |r_{\bar s u}(0)|,\label{kstar}\end{aligned}\ ] ] where @xmath111 denotes the radial wave function in the system of @xmath112 , @xmath113 $ ] is the spin - averaged mass of @xmath81 and @xmath71 , and @xmath114 is the constituent reduced mass for @xmath91 , so that @xmath115 m_{\bar s u}[1s ] } { m_{\bar d u}[1s]+m_{\bar s u}[1s ] } \approx 0.34\ ; { \rm gev}.\ ] ] for the @xmath106 meson we have the expression similar to ( [ kstar ] ) under the substitution @xmath116 . further , we explore the static potential derived in @xcite and solve the schrdinger equation @xmath117 \psi(r ) = [ \bar\lambda(\mu_q)+2(\mu_0-\mu_q ) ] \psi(r ) , \label{se}\ ] ] for the system @xmath118 , so that the binding energy @xmath119 of @xmath120-level is related with the mass @xmath121 = \bar\lambda(\mu_q)+2 \delta\mu , \label{m1s}\ ] ] and it is shown in fig . [ bound ] at @xmath122 gev , @xmath123 gev versus the light quark constituent mass @xmath124 with @xmath125 . in ( [ m1s ] ) we do not add the constituent masses of light quarks into the mass of meson , since the constituent masses are really the parts of potential energy @xmath126 in the confining quark - gluon string . ( 95,65 ) ( 0,1)=90 ( 3,60)@xmath127 $ ] , gev ( 85,0)@xmath124 , gev the mass of bound state shows the minimum versus the constituent mass at @xmath128 , which gives the optimal value of mass for the calculation of radial wave function . for the constituent mass of strange quark we use @xmath129 with @xmath130 gev , which represents the current mass at the scale of 1 gev @xcite . at this stage the estimates of coupling constants in the potential model can be optimally got according to ( [ kscalar ] ) and ( [ kstar ] ) . however , the corrections by both the quark - gluon loops and a relativistic motion can be rather essential , that can be taken into account by the introduction of @xmath131-factor , @xmath132 at @xmath133 we get the estimates @xmath134 the @xmath135-factor should generally depend on the spin and flavor of current under srudy . the above estimates show that the dependence on the flavors of quarks composing the bound state is rather suppressed , since we have amazingly reproduced the coupling constants of vector states in the limits of experimental intervals with the uniform @xmath135-factor . as for the dependence on the quantum numbers of the meson , we expect that the variation of @xmath131-factor is negligibly small because the summed quark spin in both @xmath81 and @xmath91 is equal to 1 , while the spin - orbital contributions are usually suppressed . thus , the estimate in ( [ kscalar ] ) should be quite accurate up to 5 mev , as it does for @xmath106 and @xmath81 . nevertheless , we permit a conservative variation @xmath136 further , we can compare the model estimates with the experimental data on @xmath2 decays listed in the introduction . this analysis is presented in figs . [ f - f0 ] and [ f - fpm ] . we draw the conclusion on the model is well adjusted in describing the data . ( 95,70 ) ( 0,1)=90 ( 3,65)@xmath25 ( 85,0)@xmath105 , gev ( 95,70 ) ( 0,1)=90 ( 3,65)@xmath137 ( 85,0)@xmath105 , gev according to ( [ lp - m ] ) and ( [ fp - m ] ) the values of @xmath24 and @xmath138 are independent of @xmath105 . numerically , we get @xmath139 which are in a good agreement with both the experimental data and predictions of @xmath70pt . further , we test the model under the callan treiman relation , that expresses the sum of vector - current form factors in terms of leptonic constants of kaon and pion : @xmath140 in the model under study we get @xmath141 where we have neglected the kaon mass with respect to the scalar meson one . then , numerically the relations result in @xmath142 under the variation in ( [ limits ] ) . so , at @xmath143 mev we deduce @xmath144 the systematic error caused by the approximation , as we see , is about 5 mev , and conservatively one expects @xmath145 which is in a good agreement with the known data . neglecting both the deviation of @xmath138 from the unit and the kaon mass with respect to the mass of scalar @xmath146 , we can derive from ( [ ct ] ) and ( [ ctmd ] ) the dashen weinstein relation @xmath147 both relations by callan treiman and dashen weinstein can acquire valuable numerical corrections in the model under study as well as in the @xmath70pt . so , from the formula for @xmath25 we get @xmath148 so that the displacement of @xmath149 points to the possible size of corrections . then , we calculate the expression for the hadronic matrix element of tensor quark - current @xmath150 where we have neglected the dependence of @xmath151 on @xmath16 , since the antisymmetric tensor is linear in @xmath152 . formula ( [ sigmah ] ) can be compared with the general expression @xmath153 so that @xmath154 depends on a single additional quantity @xmath155 @xmath156 where we have explored the definition @xmath157 with an evident condition of self - consistency @xmath158 in the model of meson dominance we get @xmath159 neglecting the current mass of light quark , at @xmath85 we find @xmath160 the physical meaning of @xmath161 is rather simple : they determine the difference between the fractions of meson momenta carried by the @xmath162 and @xmath54 quarks in the kaon and pion under the weak transition . at @xmath163 we get @xmath164 neglecting the suppresed contributions by the scalar and tensor form factors in ( [ me ] ) , we calculate the matrix element squared for the lepton with the spin polarization @xmath165 , satisfying the conditions of @xmath166 and @xmath167 . then , omiting an irrelevant overall normalization factor and putting the vector form factors to be real , we get @xmath168 & & 2 f_{+ } f_{-}\,m_l\,(p_l \cdot p_\nu)\ , ( p \cdot s ) -2f_+^2\,m_l ( p_\nu\cdot p)\ , ( p \cdot s ) + \label{polme2 } \\[2 mm ] & & 2{f_+}{f_-}\,{m_l}\ , ( p_l \cdot p)\,(p_\nu \cdot s ) + m_l\ , \big({p^2}\ , f_{+}^{2}+f_{-}^{2}\ , m_{l}^{2}\big)\ , ( p_\nu \cdot s ) . \nonumber \end{aligned}\ ] ] following the ordinary definition for the polarization @xmath169 , @xmath170 where @xmath171 denotes the longitudinal four - vector @xmath172 the unit vector @xmath173 lies in the decay plane , and it is orthogonal to @xmath171 , while @xmath174 is transversal to both @xmath171 and @xmath173 . ( 100,100 ) ( 5,5)=90 ( 85,0)@xmath175 ( 3,98)@xmath176 ( 59,63)@xmath177 ( 59,47)@xmath178 ( 59,38)@xmath179 ( 59,32)@xmath180 ( 100,95 ) ( 5,25)=90 ( 85,20)@xmath181 ( 55,50)@xmath182 ( 3,82)@xmath183 ( 160,70 ) ( 0,5 ) ( 80,5 ) ( 0,43)@xmath184 ( 25,10)@xmath185 ( 66,18)@xmath181 ( 85,43)@xmath186 ( 105,10)@xmath185 ( 146,18)@xmath181 the scalar products in ( [ polme2 ] ) can be easily expressed in terms of pion and lepton energies . so , for the longitudinal polarization we get @xmath187 , \\[6 mm ] p\cdot s & = & \displaystyle \frac{1}{m_l|\boldsymbol p_l|}\ , [ e_\pi |\boldsymbol p_l| - e_l^2 e_\pi + e_l\ , ( p_l\cdot p_\pi)]+\frac{m_k |\boldsymbol p_l|}{m_l}. \end{array}\ ] ] the results for the muon and electron modes are shown in figs . [ mu ] and [ el ] , respectively . as we can expect from ( [ polme2 ] ) , the variation of longitudinal polarization is significant for the muon in contrast to the electron , since the spin dependence exhibits the suppression by the lepton mass . the longitudinal polarization effects for the electron mode are negligibly small . in fig . [ mu ] we see that the longitudinal polarization of the muon is essentially negative in the dominant part of dalitz plot . the significant variation of form factor @xmath188 by a factor of 5 shows a weak sensetivity of longitudinal polarization to @xmath188 . [ el ] exhibits that the deviation of electron polarization from @xmath189 is negligible . further , we have calculated the normal polarization of leptons as shown in fig . we see that the muon has a significant variation of normal polarization , while the electron spin in the normal direction is quite small ( about 0.2% ) , and it is sizable ( about 10% ) in the region , where the number of events is essentailly suppressed . ( 100,100 ) ( 5,5)=90 ( 85,0)@xmath185 ( 3,98)@xmath181 ( 33,98)@xmath190 $ ] ( 33,61)@xmath191 ( 34,47)@xmath192 ( 44,32)@xmath193 ( 100,100 ) ( 5,5)=90 ( 85,0)@xmath185 ( 3,98)@xmath181 ( 33,98)@xmath194\cdot 10 ^ 2 $ ] ( 53,64)@xmath195 ( 57,39)@xmath196 ( 60,27.5)@xmath197 under the determination of hadronic matrix elements of quark currents we derive the ratios of form factors due to the contribution of leptoquark interactions , @xmath198 \frac{f_t}{f_+(0 ) } & = & -\frac{\sqrt{2}}{32 g_{\rm f } where we have supposed the positive definiteness of yukawa - constant products with respect to the mixing @xmath13 . then we extract the values of leptoquark scales in the tensor part , @xmath199 while the scalar form factor gives more stringent limit @xmath200 thus , we deduce the 95%-confidence level @xmath201 let us compare the above restriction on the parameters of leptoquark interactions with the constraints following from other processes relevant to the effective vertices induced by diagrams in fig . since the yukawa constants are flavor dependent , the direct constraints can be obtained from the leptonic decays of kaon , _ viz . _ , from both the electron and muon ones . in this way , the tensor interaction does not contribute , while the scalar one results in the multiplicative scaling of the decay amplitude . the factor has the form @xmath202 where we have neglected the masses of pion and @xmath54-quark , and @xmath203 denotes the mass of lepton . the leptonic modes are measured with the accuracy of branching ratios @xmath204 that can be used in order to restrict the scalar interactions induced by the leptoquarks . so , taking the ratio of branching ratios , which is independent of both the leptonic constant of kaon and the ckm element @xmath205 , we get the expression @xmath206 where we expand in small corrections following from the leptoquark interactions . comparing with the experimental result @xmath207 we find @xmath208 thus , the measurements of semileptonic kaon decay provide us with the soft confirmation of constraints following from the leptonic decays , since the tensor and scalar effective vertices correlate in the leptoquark interactions . in this paper we have developed a model of meson dominance , which has allowed us to get quite an accurate description of hadronic form factors in the decay @xmath1 . in this way we have adjusted the model under the experimental data on the matrix element of vector quark - current and calculated the matrix element of tensor current induced by the leptoquark interactions . the experimental data on the semileptonic decay of kaon allow us to extract the constraints on the contributions beyond the standard model , so that @xmath209 where @xmath69 represents the ratio of leptoquark mass to the square of yukawa - like coupling . this limit softly confirms the bounds following from the leptonic decays of kaon . * * k. horie _ et al . _ [ kek - e246 collaboration ] , phys . b * 513 * , 311 ( 2001 ) + [ arxiv : hep - ex/0106006 ] ; + a. s. levchenko _ et al . _ [ kek - ps e246 collaboration ] , arxiv : hep - ex/0111048 . i. v. ajinenko _ et al . _ , preprint ihep 2001 - 51 , arxiv : hep - ex/0112023 ; + i. v. ajinenko _ et al . _ , preprint ihep 2002 - 6 , arxiv : hep - ph/0202061 . d. e. groom _ et al . _ [ particle data group collaboration ] , eur . j. c * 15 * , 1 ( 2000 ) . v. v. braguta , a. a. likhoded and a. e. chalov , phys . d * 65 * , 054038 ( 2002 ) [ arxiv : hep - ph/0106147 ] ; + v. v. braguta , a. a. likhoded and a. e. chalov , arxiv : hep - ph/0105111 ; + r. n. rogalev , phys . b * 521 * , 243 ( 2001 ) [ arxiv : hep - ph/0105187 ] ; + y. kudenko , part . * 106 * , 31 ( 2001 ) . k. anikeev _ et al . _ , arxiv : hep - ph/0201071 ; + v. v. kiselev , arxiv : hep - ph/0109089 . m. v. chizhov , phys . b * 381 * , 359 ( 1996 ) [ arxiv : hep - ph/9511287 ] . r. j. tesarek [ ktev collaboration ] , arxiv : hep - ex/9903069 . w. buchmuller , r. ruckl and d. wyler , phys . b * 191 * , 442 ( 1987 ) [ erratum - ibid . b * 448 * , 320 ( 1987 ) ] . j. kalinowski , r. ruckl , h. spiesberger and p. m. zerwas , z. phys . c * 74 * , 595 ( 1997 ) [ arxiv : hep - ph/9703288 ] . g. abbiendi _ et al . _ [ opal collaboration ] , phys . b * 526 * , 233 ( 2002 ) + [ arxiv : hep - ex/0112024 ] . j. gasser and h. leutwyler , nucl . b * 250 * , 465 ( 1985 ) , nucl . b * 250 * , 517 ( 1985 ) . v. v. kiselev , a. e. kovalsky and a. i. onishchenko , phys . d * 64 * , 054009 ( 2001 ) [ arxiv : hep - ph/0005020 ] . s. narison , arxiv : hep - ph/0202200 . s. s. gershtein , a. a. likhoded and a. i. onishchenko , phys . rept . * 320 * , 159 ( 1999 ) .

in the framework of scalar - vector dominance we calculate the hadronic matrix elements of scalar and tensor effective quark currents induced by virtual leptoquark interactions . combined bounds on the product of couplings and leptoquark masses are obtained from experimental data . * contributions of leptoquark interactions into the tensor and scalar form factors of @xmath0 decay * + _ v.v.kiselev , a.k.likhoded , v.f.obraztsov_ + russian state research center `` institute for high energy physics '' , + protvino , moscow region , 142280 russia + fax : ( 0967)-744739 , e - mail : kiselev@th1.ihep.su

Tweet with a location You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more ||||| The fear and uncertainty ended for Chance and other journalists at the Rixos al Nasr Hotel in Tripoli late Wednesday when forces loyal to deposed Libyan ruler Moammar Gaddafi released them and walked away after five tense days of confinement. Among those set free was the Rev. Walter E. Fauntroy, the District’s former delegate in Congress, who apparently was in Tripoli hoping to arrange peace negotiations. Chance said Fauntroy, 78, was among those who safely left the hotel in a convoy arranged by the International Committee of the Red Cross. The captives — most of whom represented international news organizations — were barred from leaving the hotel by about a dozen young men who stood guard in the Rixos’s marble lobby and roamed its corridors armed with assault rifles. Food and water dwindled over the course of the ordeal, forcing the captives to ration whatever they could scavenge from the hotel’s stocks. Air conditioning was intermittent, as was electricity, cutting off the journalists’ contact with the world outside. The Libyan guards’ isolation was apparent, too; they appeared to believe their country was still controlled by Gaddafi even after rebels had stormed his compound about a mile from the Rixos. While officials from the Red Cross tried to broker an end to the stalemate from outside the hotel, CNN producer Jomana Karadsheh tried to reason with her captors inside. Karadsheh, a Jordanian, told the men in Arabic that Gaddafi’s 42-year regime was crumbling. She also told one of them, “I really miss my family and want to see them,” she said on CNN on Wednesday. The guard, who had told Karadsheh about his own family, “had tears in his eyes at that moment. I sat with him and told him things are changing out there. I said, ‘You have to think of your kids. You have to let us go.’ It was a slow process, a messy one.” The reporters, many of whom wore body armor and helmets, left the hotel around 4:30 p.m. Tripoli time in the company of Red Cross officials. They were driven through rebel checkpoints — one a mere 150 meters from the hotel — and taken to another hotel, the Corinthia, in a safe area. They were reunited with friends and fellow journalists amid hugs and tears. Fauntroy, a longtime civil rights activist, retired two years ago as pastor of the New Bethel Baptist Church in Washington’s Shaw neighborhood. He remains a member of the church. A church employee said she had no information about his condition, but Rep. Eleanor Holmes Norton (D), who succeeded Fauntroy as the District’s nonvoting representative in Congress, said in a statement that Fauntroy is expected to leave Libya soon. ||||| Chance, standing on far left, with other journalists who were held in the Rixos Hotel. | AP NEW YORK -- For the past six days, CNN's Matthew Chance feared that he and roughly 35 journalists trapped by Gaddafi loyalists in Tripoli's Rixos hotel might be somehow used as part of the crumbling regime's endgame -- or even executed. "We had been acting out in our heads these paranoid scenarios," Chance told The Huffington Post by satellite phone from Tripoli, just hours after safely escaping the hotel with his colleagues. While the journalists' Libyan government minders had already fled, several Gaddafi gunmen wouldn't let them leave. That led to days of uncertainty for the journalists, as Chance and others remained cautious in how they described the ordeal for fear of repercussions. "We took a decision collectively, the journalists in the hotel, that we wouldn't describe our situation as a hostage situation even though that's clearly what it was," Chance said. "We were being held against our will." As rebels took control of Tripoli, Chance and the others faced miserable conditions inside the hotel that had housed foreign journalists during the war and had now become one of the Gaddafi loyalists' last strongholds. At times, the journalists were forced to lie down in a dark room without electricity, air conditioning or running water. Meanwhile, artillery shells fell and stray bullets struck the building. Understandably, Chance said journalists inside were "depressed," "felt like [they] were victims," and "were very frustrated that we couldn't get stories out, communications out." But Chance got out news when he could. On Sunday, Chance appeared on CNN via Skype in a riveting 15-minute segment, complete with armed gunman yelling below. WATCH: And the following day, Chance broke the news on Twitter that Saif Gaddafi, the strongman's heir apparent, had not been captured as the NTC reported. Although Chance has had a Twitter account for nearly two years, he barely used it before being trapped in the Rixos. Over the past few days, his Twitter feed made for compelling reading as Chance tweeted everything from the darkest moments (gunfire and lack of electricity) to more light-hearted situations (stealing cheese in a hotel pantry). "I've never really used Twitter before," Chance aid. "I'm a convert now, though." "I think as you're following somebody, you can really get a sense of what's going on in a more intimate way than virtually any other medium," he added. "I felt that I was communicating with a whole bunch of people who wanted to know more." Chance, accustomed to collecting lots of information in order to produce a larger television package, embraced the short-form medium as a way to get out bits of information. And together, he said, those tweets provide "a much fuller, more intimate look" inside the hotel. While Chance tried getting news outside by way of Twitter, he points out that it was only after information got inside that the gunmen let the journalists leave. It was only earlier today, he said, that the gunmen "started to believe the world outside the hotel -- that Libya had changed outside the hotel -- that this crisis came to an end." "When they accepted that Libya was a different country and there was no Gaddafi in power anymore," he continued, "they literally handed us their weapons and said, 'You can go.'" See a series of photos from the Rixos hotel during the "hostage situation":

– For the five days they were held in Tripoli’s Rixos Hotel by Moammar Gadhafi loyalists, Matthew Chance and his fellow journalists feared they could be executed or used as "human shields." "We had been acting out in our heads these paranoid scenarios," Chance told the Huffington Post hours after being freed. The loyalists "were very aggressive," Chance adds to the Washington Post. "They accused us of being spies … when someone holding a Kalashnikov accuses you of that, it can be quite unnerving." The journalists were sometimes forced to stay in a dark room with no electricity, running water, or air conditioning, as shells struck the building and bullets flew by—and, at least once, through—the windows; mortars exploded outside, and food supplies dwindled. The miserable conditions made the journalists "depressed" and "very frustrated that we couldn’t get stories out, communications out," Chance says, calling the experience "terrifying." But when the loyalists finally "accepted that Libya was a different country and there was no Gadhafi in power anymore, they literally handed us their weapons and said, 'You can go,'" Chance says. Watch Chance’s 15-minute CNN segment at left or check out his compelling Twitter feed here.

SECTION 1. SHORT TITLE. This Act may be cited as the ``Human Cloning Prohibition Act of 2002''. SEC. 2. FINDINGS. Congress makes the following findings: (1) Human cloning is unsafe, immoral, and unacceptable. (2) Federal legislation should be enacted to prohibit anyone from attempting to conduct human cloning, whether using Federal or non-Federal funds. (3) To deter human cloning, any attempt to create a human clone should be a felony subject to severe punishment. (4) The National Academies (including the National Academy of Sciences and the Institute of Medicine) and the National Bioethics Advisory Commission recommended that any legislative action undertaken to ban human cloning should be careful not to interfere with important areas of scientific research, such as nuclear transplantation to produce stem cells. (5) The National Academies found that there are significant differences between human cloning and nuclear transplantation. Specifically, the Academies determined that, unlike human cloning, the creation of embryonic stem cells by nuclear transplantation does not involve implantation of an embryo in a uterus and thus cannot produce a complete, live-born animal (that is, a ``clone''). (6) The National Academies found that scientific and medical considerations that justify a ban on human cloning are not applicable to nuclear transplantation. (7) The National Academies concluded that nuclear transplantation has great potential to increase the understanding and potential treatment of various diseases and debilitating disorders, as well as our fundamental biological knowledge. These diseases and disorders include Lou Gehrig's disease, Parkinson's disease, Alzheimer's disease, spinal-cord injury, cancer, cardiovascular diseases, diabetes, rheumatoid arthritis, and many others. (8) The National Academies determined that nuclear transplantation research could improve our ability to transplant healthy tissue derived from stem cells into patients with damaged or diseased organs. Such research could greatly reduce the likelihood that a person's body would reject that tissue and also help obviate the need for immunosuppressive drugs, which often have severe and potentially life-threatening side effects. (9) Based on these expert conclusions and recommendations and other evidence, nuclear transplantation is a valuable area of research that could potentially save millions of lives and relieve the suffering of countless others, and thus should not be banned. (10) The National Academies recommended that nuclear transplantation experiments should be subject to close scrutiny under the Federal procedures and rules concerning human- subjects research. (11) Given the need for additional oversight in this area, strict ethical requirements for human subjects research, including informed consent, safety and privacy protections, and review by an ethics board, should be prescribed for all research involving nuclear transplantation, whether using Federal or non-Federal funds. (12)(A) Biomedical research and clinical facilities engage in and affect interstate commerce. (B) The services provided by clinical facilities move in interstate commerce. (C) Patients travel regularly across State lines in order to access clinical facilities. (D) Biomedical research and clinical facilities engage scientists, doctors, and others in an interstate market, and contract for research and purchase medical and other supplies in an interstate market. SEC. 3. PURPOSES. It is the purpose of this Act to prohibit human cloning and to protect important areas of medical research, including stem cell research. SEC. 4. PROHIBITION ON HUMAN CLONING. (a) In General.--Title 18, United States Code, is amended by inserting after chapter 15, the following: ``CHAPTER 16--PROHIBITION ON HUMAN CLONING ``Sec. ``301. Prohibition on human cloning. ``Sec. 301. Prohibition on human cloning ``(a) Definitions.--In this section: ``(1) Human cloning.--The term `human cloning' means implanting or attempting to implant the product of nuclear transplantation into a uterus or the functional equivalent of a uterus. ``(2) Human somatic cell.--The term `human somatic cell' means any human cell other than a haploid germ cell. ``(3) Nuclear transplantation.--The term `nuclear transplantation' means transferring the nucleus of a human somatic cell into an oocyte from which the nucleus or all chromosomes have been or will be removed or rendered inert. ``(4) Nucleus.--The term `nucleus' means the cell structure that houses the chromosomes. ``(5) Oocyte.--The term `oocyte' means the female germ cell, the egg. ``(b) Prohibitions on Human Cloning.--It shall be unlawful for any person or other legal entity, public or private-- ``(1) to conduct or attempt to conduct human cloning; or ``(2) to ship the product of nuclear transplantation in interstate or foreign commerce for the purpose of human cloning in the United States or elsewhere. ``(c) Protection of Research.--Nothing in this section shall be construed to restrict practices not expressly prohibited in this section. ``(d) Penalties.-- ``(1) Criminal penalties.--Whoever intentionally violates paragraph (1) or (2) of subsection (b) shall be fined under this title and imprisoned not more than 10 years. ``(2) Civil penalties.--Whoever intentionally violates paragraph (1) or (2) of subsection (b) shall be subject to a civil penalty of $1,000,000 or three times the gross pecuniary gain resulting from the violation, whichever is greater. ``(3) Forfeiture.--Any property, real or personal, derived from or used to commit a violation or attempted violation of the provisions of subsection (b), or any property traceable to such property, shall be subject to forfeiture to the United States in accordance with the procedures set forth in chapter 46 of title 18, United States Code. ``(e) Right of Action.--Nothing in this section shall be construed to give any individual or person a private right of action.''. (b) Ethical Requirements for Nuclear Transplantation Research.-- Part H of title IV of the Public Health Service Act (42 U.S.C. 289 et seq.) is amended by adding at the end the following: ``SEC. 498C. ETHICAL REQUIREMENTS FOR NUCLEAR TRANSPLANTATION RESEARCH, INCLUDING INFORMED CONSENT, INSTITUTIONAL REVIEW BOARD REVIEW, AND PROTECTION FOR SAFETY AND PRIVACY. ``(a) Definitions.--In this section: ``(1) Human somatic cell.--The term `human somatic cell' means any human cell other than a haploid germ cell. ``(2) Nuclear transplantation.--The term `nuclear transplantation' means transferring the nucleus of a human somatic cell into an oocyte from which the nucleus or all chromosomes have been or will be removed or rendered inert. ``(3) Nucleus.--The term `nucleus' means the cell structure that houses the chromosomes. ``(4) Oocyte.--The term `oocyte' means the female germ cell, the egg. ``(b) Applicability of Federal Ethical Standards to Nuclear Transplantation Research.--Research involving nuclear transplantation shall be conducted in accordance with subparts A and B of part 46 of title 45, Code of Federal Regulations (as in effect on the date of enactment of the Human Cloning Prohibition Act of 2002). ``(c) Civil Penalties.--Whoever intentionally violates subsection (b) shall be subject to a civil penalty in an amount that is appropriate for the violation involved, but not more than $250,000. ``(d) Enforcement.--The Secretary of Health and Human Services shall have the exclusive authority to enforce this section.''.

Human Cloning Prohibition Act of 2002 - Amends the Federal criminal code to prohibit: (1) conducting or attempting to conduct human cloning; or (2) shipping the product of nuclear transplantation in interstate or foreign commerce for the purpose of human cloning.Provides that nothing in this Act shall be construed to restrict practices not expressly prohibited.Prescribes civil and criminal penalties for violations and subjects any real or personal property derived from or used to commit a violation to forfeiture.Amends the Public Health Service Act to require research involving nuclear transplantation to be conducted in accordance with certain Federal standards for the protection of human subjects.

How Hermès kept its All About Women event in New York under wraps is a mystery. On Tuesday, over 700 people arrived at a vacant Wall Street building that even the previous day had looked boarded up from the outside, and found that the French luxury house had transformed it into a very chic fantasy world. Dancers modeling Hermès bags to a choreographed routine? Check. A “bangle bar” where women handed you glasses of champagne, their arms adorned with enamel Hermès bangle bracelets? Check. A “horseplay” room with vintage pinball machines and a mechanical horse that you could ride? Check. (Martha Stewart loved the horse.) A fortune-teller revealing your future based on silk patterns? Synchronized dancers at a pool? A woman in fishnets tap-dancing in Hermès riding boots? Check, check, and check. But first came the firm’s fall women’s ready-to-wear runway show, shown for the first time ever in the U.S. After wandering around the literally dozens of rooms, all showcasing different Hermès products in novel ways, we were led upstairs to dinner—by a cavalcade of men, dancing, singing, and waving white pompoms, cheerleader style. “The Pompom boys,” they were dubbed. Jodie Foster is a Hermès fan. “I think my favorite things, really, are the blankets,” she told VF Daily. “They’re really something.” Scout Willis has a healthy attitude toward the super-luxe brand, as well. “I got for my 18th birthday the ‘H’ belt, which I think is a suitable 18-year-old, like, step into the Hermès world,” she said. “I kind of think it’s vulgar when girls have, like, a Kelly bag or a Birkin bag too soon. I feel like they should be inherited, well-loved,” Willis added, laughing. Stewart had on a new Hermès blouse on at the event, but said her favorite piece is one she’s had for 15 years. “It is this beautiful leather jacket that I wear a lot,” she told us. “It’s leather lined with cashmere, and it is gorgeous.” Another thing Stewart is enamored of these days is her drone. “It has a little camera. You connect it to your iPhone, and you can control it with your iPhone, and it flies all over my farm and takes pictures,” she said. “It takes wonderful aerial photographs.” The lifestyle queen says there have been no mishaps with the gadget; it has not scratched her car or broken a window. Although she admits she only uses it outdoors. “You can use it inside also, but I don’t, because it can bang into stuff.” She makes sure that her farm animals don’t get spooked by the flying drone. “I keep it up pretty high,” Stewart explained. “And you can control the altitude, you can control the speed, you can control where it’s going. It’s easy to use, actually. You can really control it, it’s gentle. It’s lightweight, too; it’s very beautiful.” Have the neighbors called the authorities, reporting a U.F.O.? “No. I don’t have any neighbors,” she said, laughing. ||||| “Another thing Stewart is enamored of these days is her drone. ‘It has a little camera. You connect it to your iPhone, and you can control it with your iPhone, and it flies all over my farm and takes pictures,’ she said. ‘It takes wonderful aerial photographs.’ . . . Have the neighbors called the authorities, reporting a U.F.O.? ‘No, I don’t have any neighbors,’ she said, laughing. --VanityFair.com I read somewhere that Cubism would never have developed as an artistic school without the invention of the airplane. And that’s why I love my drone: for the new vantage point he gives me. Also, he’s a big hit at parties. At my barbecue on the Fourth, he hovered just inches over Charlie Rose’s head for thirty minutes, did a dive-bomber reconnaissance of Rosie O’Donnell’s iced tea, and then buzzed my nephew’s ear hair. Fun. When people first hear about my new aerial helper, they usually ask, Couldn’t you just stand on a ladder or your roof to take pictures? Of course I could. I could do a lot of things. But, you know, you get to a certain point with a thirty-year-old, multimillion-dollar lifestyle conglomerate where you think, I don’t care if I handcraft another fucking perforated-tin pie safe ever again. Truly. Remember that great line Oprah supposedly said, “Oprah doesn’t do stairs”? That’s exactly where I am now. Martha doesn’t do ladders. I studied history at Barnard, so the big picture here is not lost on me. I mean, I’m sure that the first person to own an automobile on his block faced a lot of envy and awkward staring, just as I’m sure that the mass production of butter was looked at askance by those blessed with churns. The thing is, robots and artificial intelligence do not have to be sinister. Everyone thinks “Metropolis” or “Prometheus,” but remember Hal, in “2001”? He had some winning, button-cute characteristics. Sure, he kills those two astronauts and then whacks the other hibernating crew members in their sleep, but we’ve all had that kind of day. I don’t know why the Mankiewiczes's house has been vacant for six months now, and I don’t know why the Rogerses’s place won’t sell, and I’ve never really been interested in what’s going on in that orangey ranch house. I can assure you that if I wanted to take pictures of my neighbors, I wouldn’t be doing it on the sly: I’d hire a fabulous photographer and then mise-en-scène it into something really palatable. I mean, I’m not Diane Arbus. My daughter, Alexis, says that I should Instagram all the photos just to shut everyone up, but do I really need to take that route? Where do we draw the line here? Sometimes in a restaurant I’ll see my waiter’s face reflected on the backside of a soup spoon—should he be able to buy that image or prevent its dissemination? No one was ever in anguish over the rights to the images in Plato’s cave, and not just because of the moss and the smell of urine. In our age, each individual is responsible for knowing that sometimes "N.S.A." means "No Strings Attached" and sometimes it means "String City." Figure it out. But the bigger point here is that robots are the next minority. You can put that trans person from “Orange Is the New Black” on the cover of “Time,” and suddenly a lot of gendered ambiguity feels more attractive and easier to parse, but, when it comes to robots, you really want to know someone who knows one, so that she can model behavior for you. Admittedly, sometimes when I traipse into the former smokehouse on my property where I’m boarding the drone, there’s a tiny tang of Lady Chatterley or “Mandingo” about the whole thing, but that’s just lizardy, collective-unconscious stuff. If robots are truly going to become our companions and helpmeets in the future, we need to get over this sense of them being “other.” My recent dating experiences with gentlemen my age have led me to an important discovery: be grateful for any man who shows up on time and whose rotor is always working. ||||| There’s been a lot of discussion and a tremendous amount of speculation lately about the nature of drones and their role in our society as useful tools and hobbyist toys. Last year, while celebrating my birthday in Maine, I was given a drone fitted with a high-definition camera. After a quick introduction to the mechanics of operating the contraption and a few words about its idiosyncrasies, I loaded the appropriate app on my iPad and went down to the beach. In just a few minutes I was hooked. In near silence, the drone rose, hovered, and dove, silently and surreptitiously photographing us and the landscape around us. The photos and video were stunning. By assuming unusual vantage points, the drone allowed me to “see” so much more of my surroundings than usual. The view I was “seeing” on my iPad with the help of the drone would have otherwise been impossible without the use of a private plane, helicopter, or balloon. With any of those vehicles, I would have needed a telephoto lens, and all of them would have made an unacceptable commotion on the beach. What’s more, I would not have been in the photos! So much has been done in the past without drones, airplanes, hot air balloons, or even extension ladders. It is hard to imagine André Le Nôtre laying out the exquisite landscape designs for Vaux-le-Vicomte, and later the magnificent Château de Versailles, with no high hill to stand on, no helicopter to fly in, and no drone to show him the complexities of the terrain. Yet he did, and with extreme precision, accuracy, and high style. Earlier, Henri IV drew up complicated plans for the immense and elegant redesign of Paris, capital of France. In England, Capability Brown somehow had the innate vision and perspicacity to reconfigure thousands of acres into country estates fit for royalty. He and Sir Humphry Repton invented an entirely new style of landscape design that had little to do with the grand châteaux of France. It became all about the “axis of vision” — relaxed, looming views of the distance that, without an aerial view, required the utmost in fertile imagination. In the late 1800s, more people wanted the bird’s eye view of city and country and went to extreme lengths to rig up guy-wired telescoping towers, build extension ladders of dangerous lengths, and man hot air balloons, from which intrepid photographers could capture remarkable images—such as those of the Chicago Union Stock Yards and the U.S. Steel Corporation—from heights of 2,000 feet. What about the Great Wall of China, or the Nazca Lines in southern Peru? I began reflecting on how the engineers and architects of the past accomplished so much without the modern tools we have at our disposal. My mind started racing and I imagined all the different applications for my drone. I knew that every type of use had already been thought of by others (governmental agencies, businesses, Amazon.com, Google Maps), and I knew I could not even begin to fathom even a fraction of the social, ethical, and political challenges the widespread use of drones would create. Do they raise legitimate privacy concerns? Should they be regulated? Should we have a national debate? I don’t have all the answers. But I forged ahead, using a Parrot AR Drone 2.0, photographing my properties, a party, a hike in the mountains, and a day at the beach. I did my best to master the moves and angles that would result in most arresting pictures and video. An aerial photo of Martha Stewart’s farm in Bedford, New York, taken with her drone. Martha Stewart One of my farm workers used his drone, a DJI Phantom flying camera, to capture amazing images of my 153-acre farm in Bedford, New York. Suddenly we could see with astonishing clarity the layout of the open fields, the horse paddocks, the chicken coops, the greenhouses, the hay barn, the cutting gardens and henhouses, the clematis pergola, and the long allée of boxwood. The photos were so good I posted them to my blog on Marthastewart.com. The response was phenomenal! Henry Alford wrote a satirical essay about me and my drones in The New Yorker that was really funny but missed the point about why I love my drone. Drones can be useful tools, and I am all about useful tools. One of my mottos is “the right tool for the right job.” A few facts: The hobbyist drones we can all purchase online or in stores are technically known as UAS: unmanned aerial systems. Many can fly up to 900 feet. With practice, a novice photographer can take really great photos. The shots of my farm were breathtaking and showed not only a very good landscape design — thanks to the surveyors and landscapers who worked with me on the overall vision, much as le Notre worked with Louis XIV — they also showed me what more I can do in the future, and revealed unexpected beauty. An aerial shot of the vegetable garden looked very much like my Peter Rabbit marzipan embellished Easter cake, which was designed without the help of a drone. Martha Stewart, founder of Martha Stewart Living Omnimedia and Emmy Award-winning television show host, entrepreneur and bestselling author, is America’s most trusted lifestyle expert and teacher. Contact us at editors@time.com. ||||| Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period.

– Martha Stewart is, apparently, a really big fan of drones. She told Vanity Fair all about her love for drone photography, she's celebrated it on her blog, and now she's explaining her feelings in Time. She received a photo-taking drone for her birthday, she writes, and has used it to take pictures of all kinds of landscapes, from the beach to "my properties," including a shot of a vegetable garden that "looked very much like my Peter Rabbit marzipan embellished Easter cake." Drones like hers—which anyone can buy, she notes—connect to a tablet for viewing purposes. "By assuming unusual vantage points, the drone allowed me to 'see' so much more of my surroundings than usual," she writes. As for privacy concerns over limitless photography, "I don't have all the answers," she writes. At Salon, Prachi Gupta points out that in fact, Stewart "has precisely zero answers." But that doesn't stop her from considering the wonders of landscaping and architecture achieved over the centuries without drones, and wondering about the possibilities the devices could offer in the future. The essay is, in part, a response to an amusing New Yorker parody of Stewart's drone fandom, by Henry Alford. Meanwhile, Gizmodo notes that Stewart can't stop tweeting about drones.

Washington (CNN) President Donald Trump tried to end the special counsel probe in December, marking the second known attempt to do so, The New York Times reported Tuesday. The Times report on Tuesday evening came as CNN reported that Trump is considering firing Deputy Attorney General Rod Rosenstein , who has oversight of the Mueller probe, following a federal raid on Trump's personal attorney Michael Cohen. In December, angered by reports of subpoenas for information on his business with Deutsche Bank, Trump told advisers he wanted the investigation to be shut down, according to the Times' report. The Times report, based on interviews with eight sources, said the President backed down after Mueller's office told Trump's lawyers and advisers that reports about the subpoenas were inaccurate. The report outlines the second time Trump is known to have moved to quash the probe, and follows previous reporting that the President moved to fire Mueller last June, which a source said White House counsel Donald McGahn refused. Trump denied the story at the time. Read More ||||| Over the next couple of days, Mr. Trump pestered Mr. McGahn about the firing, but Mr. McGahn would not tell Mr. Rosenstein. The badgering by the president got so bad that Mr. McGahn wrote a resignation letter and was prepared to quit. It was only after Mr. McGahn made it known to senior White House officials that he was going to resign that Mr. Trump backed down. The articles that provoked Mr. Trump’s anger in December — which were published by Bloomberg, The Wall Street Journal and Reuters — said one of Mr. Mueller’s subpoenas had targeted Mr. Trump’s and his family’s banking records at Deutsche Bank. Mr. Trump’s lawyers, who have studied Mr. Trump’s bank accounts, did not believe the articles were accurate because Mr. Trump did not have his money there. The lawyers were also able to learn that federal prosecutors in a different inquiry had issued a subpoena for entities connected to the family business of Mr. Trump’s son-in-law, Jared Kushner. The news outlets later clarified the articles, saying that the subpoena to Deutsche Bank pertained to people affiliated with Mr. Trump, who was satisfied with the explanation and dropped his push to fire Mr. Mueller. The White House did not respond to an email seeking comment. Acutely conscious of the threat Mr. Mueller’s investigation poses, Mr. Trump has openly discussed ways to shut it down. Each time, he has been convinced by his lawyers and advisers that taking the step would only exacerbate his problems. In some cases, they have explained to Mr. Trump how anything that causes him to lose support from congressional Republicans could further imperil his presidency. But Mr. Trump’s statements to his advisers have been significant enough to attract attention from Mr. Mueller himself. Mr. Mueller’s investigators have interviewed current and former White House officials and have requested documents to understand whether these efforts show evidence the president is trying to obstruct the Justice Department’s investigation, according to two people briefed on the matter. Mr. Trump’s frustrations have tended to flare up in response to developments in the news, especially accounts of appearances of witnesses, whom Mr. Trump feels were unfairly and aggressively approached by investigators. They include his former communications director, Hope Hicks, and his former campaign manager, Corey Lewandowski. The venting has usually been dismissed by his advisers, many of whom insist they have come to see the statements less as direct orders than as simply how the president talks, and that he often does not follow up on his outbursts. One former adviser said that people had become conditioned to wait until Mr. Trump had raised an issue at least three times before acting on it. The president’s diatribes about Attorney General Jeff Sessions, Mr. Rosenstein and the existence of the special counsel have, for most of the White House aides, become a dependable part of the fabric of life working for this president. ||||| President Trump Donald John TrumpStone: 'I’ve never had any discussion' with Trump about a pardon White House: Trump will move forward on wall 'with or without' Dems Pelosi after Stone indictment: 'What does Putin have on the president'? MORE’s showdown with Robert Mueller Robert Swan MuellerSasse: US should applaud choice of Mueller to lead Russia probe MORE headed toward a crisis point on Tuesday, with the White House saying Trump has legal authority to fire the special counsel. Republicans unnerved by the president’s anger in public and private sought to talk him down, fearing a “Saturday night massacre”-style series of firings harking back to the Nixon era was growing more likely. GOP lawmakers fear presidential firings of Mueller, Attorney General Jeff Sessions Jefferson (Jeff) Beauregard SessionsWe can end the shutdown with billion — Trump and Democrats already agree on border security Nadler sends Whitaker questions on possible contacts with Trump over Mueller probe Graham angers Dems by digging into Clinton, Obama controversies MORE or Deputy Attorney General Rod Rosenstein Rod Jay RosensteinBarr’s first task as AG: Look at former FBI leaders’ conduct 5 myths about William Barr William Barr's only 'flaw' is that he was nominated by Trump MORE would cause chaos in Washington and dim Republican hopes of holding their congressional majorities. ADVERTISEMENT Senate Judiciary Committee Chairman Chuck Grassley Charles (Chuck) Ernest GrassleyOvernight Health Care: Lawyer alleges migrant kids behind held in unlicensed facilities | Poll shows 46 percent haven't heard of 'Medicare for all' | Lawmakers set up dueling drug pricing hearings As it applies to veterans, it is time for pay-go to go Proposed drug importation bill would expose Americans to counterfeit meds MORE (R-Iowa) declared in a CNN interview Tuesday that “it would be suicide for the president to fire him.” “I have made my views public, and I hope he’s listening to those of us who say it would be a mistake,” said Senate Republican Whip John Cornyn John CornynGeorge Conway: GOP senators bear responsibility for shutdown because they took 'idiot' Trump seriously GOP senator reportedly slams McConnell over shutdown: ‘This is your fault’ Dems strengthen hand in shutdown fight MORE (Texas). Senate Majority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellOn The Money: Trump agrees to end shutdown without wall funding | Senate quickly clears short-term funding measure | House to vote tonight | Federal workers could get back pay within days | Dems take victory lap Shutdown ends without funding for Trump’s border wall Senate expected to pass bill to end shutdown on Friday MORE (R-Ky.) insisted legislation to protect Mueller was unnecessary because cooler heads would prevail. “I haven’t seen a clear indication yet that we needed to pass something to keep him from being removed because I don’t think that’s going to happen, and that remains my view,” McConnell told reporters. “It’s still my view that Mueller should be allowed to finish his job. I think that’s the view of most people in Congress.” Trump’s fury at the FBI’s raid on Monday on Michael Cohen, his personal lawyer, has triggered the latest crisis surrounding the Mueller probe. Federal prosecutors were reportedly seeking information on payments made to two women, adult-film actress Stormy Daniels and former Playboy model Karen McDougal, who both claim to have had affairs with Trump years ago. The personal nature of the probe has clearly angered the president, who decried an unfair witch hunt of his presidency in a Tuesday morning tweet. “Attorney–client privilege is dead!” Trump tweeted. “A TOTAL WITCH HUNT!!!” The president also canceled a planned weekend trip to two South American nations. Allies of Trump were egging him on, saying they would understand if he took the step of firing officials at the Department of Justice — a decision some Republicans have said could spark a constitutional crisis. “I understand the president’s frustration with the hypocrisy playing out at the Department of Justice,” freshman Rep. Matt Gaetz Matthew (Matt) GaetzHouse passes bill expressing support for NATO Maduro starts new term in Venezuela facing US sanctions, lack of legitimacy abroad Rick Scott threw party at Florida governor’s mansion after DeSantis and family had moved in: report MORE (R-Fla.) told Fox News. “Frankly, it would be warranted if we made changes at the very top of the Department of Justice.” “I think there is a sufficient basis to fire Rosenstein in particular, and likely the attorney general for not doing his job,” he added. That suggestion shocked other Republicans. “If the president were to fire the deputy attorney general, that would be an extraordinary crisis and a real problem, and I just don’t think he’s going to do it,” said Sen. Susan Collins Susan Margaret CollinsShutdown ends without funding for Trump’s border wall Senate expected to pass bill to end shutdown on Friday GOP Sen. Collins: I'm not sure Trump understands living 'paycheck to paycheck' MORE (R-Maine). GOP lawmakers couldn’t escape questions about Trump, Cohen, Mueller and Rosenstein from reporters at the Capitol — even on a day when Facebook CEO Mark Zuckerberg Mark Elliot ZuckerbergHillicon Valley: Roger Stone indicted in Mueller probe | Zuckerberg defends Facebook's data practices | Irish data regulators probing Twitter | Zinke vows to make his crypto company 'great again' Zuckerberg defends Facebook data practices in op-ed On The Money: Shutdown Day 33 | Fight over State of the Union | Pelosi tells Trump no speech on Tuesday | Trump teases 'alternative' address | Trump adviser warns shutdown could hurt growth | Mulvaney seeks list of vulnerable programs MORE was testifying on Capitol Hill for the first time. Pushback from fellow Republicans against firing Mueller has grown stronger since the beginning of the year, when Trump’s allies mostly shrugged off speculation that the president would somehow cut short the special counsel investigation, dismissing it as an unlikely prospect. While most Republicans maintain they don’t think Trump will quash the probe, they’re less confident than before. And statements from the White House podium on Tuesday from press secretary Sarah Huckabee Sanders only added to their fears. Sanders announced that Trump “certainly believes that he has the power” to end Mueller’s investigation. The comments suggest the White House may be looking for legal arguments to back a decision to fire Mueller. Legal experts say Trump does not have the power to fire Mueller directly. Under Justice Department regulations, that authority falls to the agency official in charge of the investigation — in this case Rosenstein. It is easy to see why a Trump decision to fire Mueller would make Republicans queasy. A Quinnipiac University poll conducted this month found that 69 percent of American voters oppose Trump firing Mueller while only 13 percent support it. More than half of the Republicans polled, 55 percent, said Trump shouldn’t interfere. Republicans are worried about a wave election this fall that could cost them their House majority. There are also fears about the Senate, though the fact that Democrats are defending many more seats in the upper chamber gives Republicans more confidence about holding it. Still, many GOP senators fear firing Mueller would pose new risks to their majority. Trump also has reason to fear a Democratic takeover of the House and Senate, which would unleash investigations of his administration. Amid uncertainty over what Trump will do next, some Republicans are pushing for legislation to protect Mueller, although that path doesn’t yet have much support in the party. Sens. Thom Tillis Thomas (Thom) Roland TillisShutdown deal may be in hand; Trump to make remarks Dems strengthen hand in shutdown fight White House immigration agenda hurts Senate Republicans in 2020 MORE (R-N.C.) and Lindsey Graham Lindsey Olin GrahamHouse votes to reopen government, sending bill to Trump Shutdown ends without funding for Trump’s border wall The Hill's Morning Report — McConnell tells Pence shutdown must end MORE (R-S.C.) have sponsored bipartisan bills to protect the special counsel. The Tillis measure would empower judges to reinstate Mueller if a court found his firing to be improper. Tillis on Tuesday called for a vote on the measure. Senate Democratic Leader Charles Schumer Charles (Chuck) Ellis SchumerLou Dobbs slams Trump's move to end shutdown: 'Illegal immigrants are surely pleased’ A law enforcement solution to security on the Southern border Senators pitch three-week stopgap bill to resolve shutdown fight MORE (N.Y.) tried to ramp up pressure on Republicans Tuesday by defending the integrity of Mueller’s work and calling for Senate floor action. – Jordain Carney contributed

– President Trump tried to fire Robert Mueller in December, which is the second known time the president has attempted to get rid of the special counsel, according to the New York Times. which cites interviews with eight White House officials and other people close to Trump. The sources say Trump demanded the firing because he was enraged by media reports that Mueller had crossed his "red line" and subpoenaed Deutsche Bank seeking records on the financial dealings of the Trump family. The insiders say that Trump backed down after lawyers contacted Mueller's team and determined that the reports were what the president would describe as "FAKE NEWS." The Times reported earlier this year that the chief White House lawyer refused Trump's order to fire Mueller last June. The Times report heightened worries that Trump will fire Mueller out of anger at Monday's raid on the offices of Michael Cohen, his personal lawyer. After the raid—the result of an investigation Mueller passed to the Manhattan US attorney—Trump said it was a "disgrace" and told reporters he hadn't made up his mind yet about firing Mueller, CNN reports. Republicans, who fear firing Mueller could cause chaos, have been trying to talk him down, though Senate Majority Leader Mitch McConnell say he doesn't see a need to pass legislation to protect him from being removed, the Hill reports. "I don't think that’s going to happen, and that remains my view," McConnell said Tuesday. "It's still my view that Mueller should be allowed to finish his job. I think that's the view of most people in Congress."

here , we show that a uniform dzyaloshinskii - moriya ( dm ) interaction along chains but staggered between chains can explain that the dynamical structure factor @xmath73 leads to an esr signal and that there is , consequently , a nontrivial mode b. the symmetry of the crystal structure of dimpy ( fig . 1 of the main manuscript ) allows the occurrence of a uniform dm interaction along the leg , but staggered from leg to leg @xmath74 that corresponds to the term @xmath46 of the hamiltonian ( 1 ) in the main text . we choose coordinates in spin space such that the vector @xmath75 points in the @xmath76 direction , @xmath77 , where @xmath78 is the unit vector along the @xmath76 axis . since the dm interaction is very small , it hardly affects most physical quantities . one noteworthy exception is the selection rule of esr excitations . the mode allowed in the esr spectrum strongly depends on weak perturbations breaking the spin - rotational symmetry . normally , the esr experiment measures @xmath79 at @xmath41 . the dynamical structure factor @xmath80 is proportional to the imaginary part of the retarded green s function at @xmath41 , @xmath81\rangle , \label{gpm}\ ] ] where @xmath82 . since the prefactor in eq . does not have special resonances in frequency , the esr modes a and b mentioned in the main manuscript come from the frequency dependence of the retarded green s function . in order to investigate the origin of these modes , we utilize the following _ identity _ ( compare with the appendix of ref . @xcite ) @xmath83\rangle}{(\omega - g\mu_bh)^2 } \notag \\ & \quad + \frac 1{(\omega - g\mu_bh)^2}g^r_{\mathcal{a}\mathcal{a}^\dagger}(\omega ) \ , , \label{id}\end{aligned}\ ] ] where @xmath84 is the operator @xmath85 $ ] . according to the identity , in the absence of the dm interaction ( i.e. , @xmath86 ) , one finds a single mode at @xmath87 , which is mode a. the esr mode b is absent unless anisotropic interactions breaking the spin - rotational symmetry are present . the identity also shows that mode b comes from the last term , the retarded green s function @xmath88 . the operator @xmath84 is given by @xmath89 the above formula is exact and valid for arbitrary magnetic field . we can get an approximation valid for low energy , long wavelength by replacing @xmath90 . in that case eq . becomes @xmath91 . and one obtains @xmath92 mode b is thus directly connected to the @xmath93 spin spin correlation function in the absence of dm interactions . in order to complement the above description of mode b we employ a bosonization approach dealing with the rung interaction , @xmath14 , perturbatively . the bosonization provides a perfectly controllable treatment of the low - energy theory for @xmath94 . although for dimpy the ratio is too high to expect quantitative agreement we can expect a very good qualitative description . the standard non - abelian bosonization calculation leads to @xcite @xmath95 , \label{a_j}\ ] ] where @xmath96 is the short - distance cutoff . @xmath97 and @xmath98 are , respectively , the right - moving and the left - moving components of the @xmath99 current on the @xmath100th leg . note that the spin @xmath101 is written as @xmath102 , where @xmath103 is the nel order parameter . according to ref . @xcite , we can rewrite the operator by using two majorana fermions , @xmath104 here , @xmath105 is a non - universal constant . @xmath106 and @xmath107 are the right - moving ( left - moving ) component of the majorana fermions @xmath108 and @xmath109 . the majorana fermion @xmath108 , when it is applied to the singlet ground state at zero magnetic field , generates a triplon with @xmath110 . although ref . @xcite formulated the refermionized theory for the @xmath111 case , one can easily extend it to the high - field case of our interest . at the level of the bosonized and refermionized theory , the hamiltonian of the spin ladder at @xmath111 is split into two parts : a symmetric and an antisymmetric part with respect to the permutation of the leg index @xmath64 . the magnetic field affects the symmetric sector only and can induce a quantum phase transition from the gapped phase at low field into the field - induced tomonaga - luttinger liquid phase . conversely the majorana fermions @xmath108 and @xmath109 belong to the antisymmetric sector @xcite , are thus in first approximation unaffected by the magnetic field , and retain a gapful excitation spectrum . if we call @xmath112 the excitation gap of @xmath108 at @xmath113 , the other majorana fermion @xmath109 has a higher excitation gap @xmath114 at @xmath41 @xcite . hence , the operator generates multi - particle excitations whose excitation gap at @xmath41 equals to @xmath115 . for zero magnetic field the triplet gap @xmath112 is estimated from our exact diagonalization data as @xmath116 k ( see section [ sec : edt0 ] below ) leading to a value @xmath117 ghz of the resonance frequency of mode b in good agreement with @xmath40 ghz obtained from the extrapolation of the frequency - field dependence of the mode b to zero field ( see fig . 4 in the main text ) . at finite magnetic field the decoupling of the symmetric and antisymmetric mode would naively yield a field - independent frequency . however there are irrelevant operators that couple these two sectors . although they do not change the asymptotic physics they can renormalize the value of the parameters , hence a field dependence of the resonance that must be computed numerically . the field dependence of the dynamical structure factors in the @xmath43 and @xmath42 channels at @xmath41 along the legs has been computed at @xmath52 using exact diagonalization ( ed ) of the model hamiltonian [ eq . ( 1 ) in the main text ] for finite systems of sizes up to @xmath50 sites . for @xmath118 and in the high @xmath60 sectors we use full diagonalization , otherwise a combination of the lanczos algorithm with a continued fraction expansion @xcite . the action of the operators @xmath119 changes the quantum number @xmath60 by @xmath120 , rendering the computation of @xmath43 more challenging than @xmath42 . nevertheless , only a strong line at frequency @xmath121 has been observed in @xmath43 with an intensity subject to small finite - size effects . since furthermore the mixing of the two channels depends on parameters like the length of the dm vector @xmath122 that are not really known , we manually added a line for @xmath43 with a suitable intensity in fig . 4 of the main text . structure factor at the temperature @xmath52 and magnetic fields @xmath111 ( top panel ) , @xmath123 t ( middle panel ) , and @xmath124 t ( bottom panel ) . a lorentzian broadening of @xmath125 ghz is applied . the inset of the top panel shows a finite - size extrapolation of the frequency of the peak @xmath126 using a quadratic fit in the inverse system size @xmath127 . [ ed_size ] , title="fig : " ] + structure factor at the temperature @xmath52 and magnetic fields @xmath111 ( top panel ) , @xmath123 t ( middle panel ) , and @xmath124 t ( bottom panel ) . a lorentzian broadening of @xmath125 ghz is applied . the inset of the top panel shows a finite - size extrapolation of the frequency of the peak @xmath126 using a quadratic fit in the inverse system size @xmath127 . [ ed_size ] , title="fig : " ] + structure factor at the temperature @xmath52 and magnetic fields @xmath111 ( top panel ) , @xmath123 t ( middle panel ) , and @xmath124 t ( bottom panel ) . a lorentzian broadening of @xmath125 ghz is applied . the inset of the top panel shows a finite - size extrapolation of the frequency of the peak @xmath126 using a quadratic fit in the inverse system size @xmath127 . [ ed_size ] , title="fig : " ] we now focus on the channel @xmath42 since this exhibits a more complex behavior . for completeness , we start with the case of zero magnetic field in the top panel of fig . [ ed_size ] even if this has been investigated previously @xcite . the low - field region is particularly challenging for ed since on the one hand the numerical effort is maximal and on the other hand finite - size effects are largest , compare the position of the main peak in fig . [ ed_size ] . nevertheless , the inset of the top panel of fig . [ ed_size ] demonstrates that the peak position @xmath126 at @xmath111 can be extrapolated to @xmath128 ghz in the thermodynamic limit @xmath129 . note that a similar extrapolation can also be performed for the spin gap @xmath112 : a fit with an exponential function gives rise to @xmath130 ghz , corresponding to a first critical field @xmath131 t. as a consistency check of these two independent extrapolations , we mention that the ratio @xmath132 reproduces the field - theory prediction @xmath133 very accurately . the higher magnetic fields that are our main concern are more favorable for two reasons . firstly , exact diagonalization is performed for lower particle numbers and one can reach bigger system sizes . in addition , finite - size effects become less important . the case @xmath134 shown in the middle panel of fig . [ ed_size ] demonstrates a well - behaved case . in this case the ground state is in the sector @xmath135 ( half of the saturation magnetization ) for all considered systems and finite - size effects are virtually absent , as is demonstrated by the lines for all system sizes falling on top of each other in the middle panel of fig . [ ed_size ] . finally , the bottom panel of fig . [ ed_size ] illustrates the more typical behavior with the case @xmath136 . in this case , the ground state is in the sector @xmath137 for those @xmath138 that are divisible by @xmath139 , i.e. , @xmath140 , @xmath141 , @xmath142 , and @xmath143 in the figure . for these system sizes , again no finite - size effects are observable . on the other hand , if @xmath138 is not divisible by @xmath139 , @xmath137 can not be realized and the corresponding system sizes ( @xmath144 , @xmath145 , and @xmath146 in the figure ) scatter a bit around the thermodynamic limit . for systems with @xmath147 spins and in the high - field region , these finite - size shifts of the main line should not exceed @xmath148 ghz . above this main peak there is always a bit of spectral density corresponding to continua of excitations . since these continua need to be approximated by a finite number of peaks for fixed @xmath138 , one naturally observes that these continua are more strongly affected by finite - size effects . figure [ n32_appendix ] shows the field dependence of @xmath42 for a fixed system size of @xmath44 spins . the jumps of the `` line '' in the low - field region in fig . [ n32_appendix ] reflect again the finite - size effects discussed above , but for higher magnetic fields the main effect is that only discrete values of @xmath149 are realized for a fixed system size . 4 of the main text is based on a composite of the largest available system sizes and coincides with the present fig . [ n32_appendix ] in the region @xmath150 t ( in fig . 4 of the main text we have used @xmath151 for @xmath152 t , @xmath153 for @xmath154 t , @xmath155 for @xmath156 t , and @xmath45 for @xmath157 t ) . note that @xmath158 in the sector with @xmath159 just before saturation . in the case @xmath44 shown in the present fig . [ n32_appendix ] this implies a vanishing signal already at a field of @xmath160 t , i.e. , below the saturation field @xmath161 t. in the case of fig . 4 of the main text we have used data for @xmath45 spins just below saturation . accordingly , this apparent saturation field is closer to the true saturation field , namely at @xmath162 t. structure factor at a magnetic fields @xmath163 t ( upper panel ) and @xmath123 t ( lower panel ) . the size of the system is fixed at @xmath164 sites and a lorentzian broadening of @xmath125 ghz is applied . [ fig : szzpit>0 ] , title="fig : " ] + structure factor at a magnetic fields @xmath163 t ( upper panel ) and @xmath123 t ( lower panel ) . the size of the system is fixed at @xmath164 sites and a lorentzian broadening of @xmath125 ghz is applied . [ fig : szzpit>0 ] , title="fig : " ] finally , we take a brief look at @xmath165 . first , we need a generalization of eq . ( 2 ) of the main text @xmath166 where @xmath167 is the partition function . here we present ed results for @xmath164 sites . in this case , we can no longer obtain the full spectrum , but we need to restrict the sums over @xmath168 to low energies @xmath169 . after performing such a restriction , the spectral sum over @xmath170 is again evaluated by a continued fraction expansion @xcite . this approximation would break down at high temperatures , but is accurate for the region of interest , i.e. , temperatures @xmath171 . since we need to compute excited states with the lanczos algorithm @xcite , we have to work with smaller systems than for zero temperature . at least 20 states have been retained for each sector with a given @xmath60 and momentum @xmath172 . figure [ fig : szzpit>0 ] presents results for two cases , namely @xmath173 t ( upper panel ) and @xmath174 t ( lower panel ) . the @xmath52 limit of the latter case has been presented before in the middle panel of fig . [ ed_size ] where finite - size effects were observed to be small . at finite @xmath175 , finite - size effects are still visible as wiggles in the detailed lineshape . still , fig . [ fig : szzpit>0 ] clearly demonstrates a substantial broadening and corresponding damping as temperature is raised to 4.6 k. this is in qualitative agreement with the experimental findings ( left panel of fig . 2 and 3(a ) of the main text ) . at @xmath174 t there is no observable shift of the position of the line with temperature whereas for @xmath173 t one observes a shift of the center of mass of the line to lower frequency @xmath176 with rising temperature , at least for the @xmath164 system shown in fig . [ fig : szzpit>0 ] . given the downward slope of mode b with increasing magnetic field @xmath21 , this translates to a shift of the mode to lower fields with rising temperature when one translates the present frequency scans at constant field to field scans at constant frequency . thus , the shift observed in the upper panel of fig . [ fig : szzpit>0 ] is consistent with the shift of mode b observed experimentally ( left panel of fig . 2 of the main text ) . between @xmath52 and 1.5 k there is generally a bit of broadening , but no significant shift of the main line , justifying the comparison of @xmath52 computations with experiments performed at 1.5 k. b. thielemann , ch . regg , h. m. rnnow , a. m. luchli , j .- s . caux , b. normand , d. biner , k.w . krmer and h .- u . gdel , j. stahn , k. habicht , k. kiefer , m. boehm , d. f. mcmorrow , and j. mesot , phys . 102 * , 107204 ( 2009 ) . p. bouillot , c. kollath , a. m. luchli , m. zvonarev , b. thielemann , ch . regg , e. orignac , r. citro , m. klanjek , c. berthier , m. horvati , and t. giamarchi , phys . b. * 83 * , 054407 ( 2011 ) . d. schmidiger , p. bouillot , s. mhlbauer , s. gvasaliya , c. kollath , t. giamarchi , and a. zheludev , phys . 108 * , 167201 ( 2012 ) . r. yu , l. yin , n. s. sullivan , j. s. xia , c. huan , a. paduan - filho , n. f. oliveira jr , s. haas , a. steppke , c. f. miclea , f. weickert , r. movshovich , e .- mun , b. l. scott , v. s. zapf , and t. roscilde , nature * 489 * , 379 ( 2012 ) . a. a. validov , m. ozerov , j. wosnitza , s. a. zvyagin , m. m. turnbull , c. p. landee , and g. b. teitelbaum , j. phys . : condens . matter * 26 * , 026003 ( 2014 ) . s. c. furuya , p. bouillot , c. kollath , m. oshikawa , and t. giamarchi , phys . * 108 * , 037204 ( 2012 ) . v. n. glazkov , m. fayzullin , y. krasnikova , g. skoblin , d. schmidiger , s. mhlbauer , and a. zheludev , _ esr study of the spin ladder with uniform dzyaloshinskii - moria interaction _ ( 2015 ) , arxiv:1507.02503v2 [ cond-mat.str-el ] . t. hong , y.h . kim , c. hotta , y. takano , g. tremelling , m.m . turnbull , c.p . landee , h .- j . kang , n.b . christensen , k. lefmann , k.p . schmidt , g.s . uhrig , and c. broholm , phys . rev . lett . * 105 * , 137207 ( 2010 ) . j. l. white , c. lee , o. gunaydin - sen , l. c. tung , h. m. christen , y. j. wang , m. m. turnbull , c. p. landee , r. d. mcdonald , s. a. crooker , j. singleton , m. h. whangbo , and j. l. musfeldt , phys . b. * 81 * , 052407 ( 2010 ) . d. g. shelton , a. a. nersesyan , and a. m. tsvelik , phys . b * 53 * , 8521 ( 1996 ) . c. lanczos , j. res . 45 * , 255 ( 1950 ) . r. haydock , v. heine , and m. j. kelly , j. phys . c : solid state phys . * 5 * , 2845 ( 1972 ) . e. r. gagliano and c. a. balseiro , phys . lett . * 59 * , 2999 ( 1987 ) . e. dagotto , rev . 66 , 763 ( 1994 ) .

magnetic excitations in the strong - leg quantum spin ladder compound ( c@xmath0h@xmath1n)@xmath2cubr@xmath3 ( known as dimpy ) in the field - induced tomonaga - luttinger spin liquid phase are studied by means of high - field electron spin resonance ( esr ) spectroscopy . the presence of a gapped esr mode with unusual non - linear frequency - field dependence is revealed experimentally . using a combination of analytic and exact diagonalization methods , we compute the dynamical structure factor and identify this mode with longitudinal excitations in the antisymmetric channel . we argue that these excitations constitute a fingerprint of the spin dynamics in a strong - leg spin-1/2 heisenberg antiferromagnetic ladder and owe their esr observability to the uniform dzyaloshinskii - moriya interaction . the investigation of spin systems where quantum effects play a dominant role has become a very active branch of quantum many - body physics . although the spin hamiltonian describing quantum magnets is quite simple and often very well controlled @xcite , the interplay of all spin degrees of freedom can be very complex , leading to a large diversity of phases ranging from long - range magnetic order to spin liquids of various types @xcite . in addition , the ground state can possess not only local types of order but also more complex and subtle non - local topological orders @xcite . understanding such behavior is thus a frontier of fundamental knowledge , providing , on the other hand , a potential means for quantum computation @xcite or quantum simulators of some itinerant problems @xcite . due to enhanced quantum effects , one- and quasi - one - dimensional ( 1d ) spin systems , such as spin chains and ladders , are of particular interest @xcite . in these systems , interactions between excitations can play a very important role , giving rise to exotic states @xcite , including quasi - long - range order , known as tomonaga - luttinger liquids ( tll ) , or phases where correlations between magnetic excitations are of short range ( e.g. , in the case of haldane spin-1 chains @xcite ) . recent progress in material science makes it possible to synthesize new materials with exchange parameters permitting the manipulation of the ground states by accessible magnetic fields , with drastic effects on the physical properties . this , and the progress in both analytical and numerical techniques provide access to a host of novel physics , allowing , e.g. , the observation of the bose - einstein condensation of magnons @xcite , the quantitative test for tll predictions @xcite , the observation of fractionalization of spin excitations @xcite , spinon attraction @xcite , and remarkable effects of disorder @xcite . even very tiny anisotropies can play an important role , reducing local symmetries and drastically affecting the low - energy spin dynamics . electron spin resonance ( esr ) spectroscopy has proven to be one of the most sensitive tools to probe such interactions and effects in exchange - coupled spin systems @xcite . one remarkable advantage of this technique is that esr allows experiments in very high magnetic fields , far beyond the superconducting magnet limit @xcite . theoretical studies of predicted esr parameters are available for spin chains and ladders @xcite , and have been applied with good success to , e.g. , spin chains @xcite and strong - rung ladders @xcite . however , relatively little is known about the spin dynamics in strong - leg ladder systems , which can be very different from that in spin chains and strong - rung ladders in terms of the spinon interactions . ( color online ) schematic view of the crystal structure of dimpy @xcite . the copper ( cu ) ions form a ladder - like structure with the dominant exchange couplings indicated in the figure . , scaledwidth=45.0% ] in this work , we report on high - field esr studies of the spin ladder ( c@xmath0h@xmath1n)@xmath2cubr@xmath3 [ bis(2,3-dimethylpyridinium ) tetrabromocuprate(ii ) or ( 2,3-dmpyh)@xmath2-cubr@xmath3 , abbreviated as dimpy ] , currently known as the best realization of a strong - leg spin-1/2 heisenberg antiferromagnetic ladder @xcite with moderate exchange coupling constants . we reveal experimentally the presence of a novel esr excitation mode in the tll phase that is absent in a strong - rung ladder and was not observed in previous esr work on dimpy either @xcite . we describe the unusual excitation spectrum of dimpy , using a combination of analytic techniques and exact - diagonalization ( ed ) methods . we demonstrate that the appearance and magnetic - field dependence of parameters of the new mode can be understood by taking into account the dynamic spin - spin correlation function for the strong - leg spin-1/2 heisenberg antiferromagnetic ladder model , thus providing important information on the spin excitations as well as the anisotropy of magnetic interactions in this system . dimpy crystallizes in a monoclinic lattice with space group p2(1)/n and lattice constants @xmath4 , @xmath5 , @xmath6 , @xmath7 ( number of formula units per unit cell @xmath8 ) @xcite with @xmath9 cu@xmath10 ions arranged in a ladder - like structure ( fig . [ fig : structure ] ) . each unit cell contains two rungs , each from a different symmetry - equivalent ladder , running parallel to the @xmath11 axis . the spin hamiltonian of dimpy can be written as @xmath12 where @xmath13 and @xmath14 are exchange coupling constants along the legs and rungs , respectively , @xmath15 are the spin operators on site @xmath16 of the leg @xmath17 of the ladder , @xmath18 is the zeeman term ( @xmath19 is the @xmath19 factor , @xmath20 is the bohr magneton , @xmath21 is the applied magnetic field ) . the fourth term represents various possible , usually small , anisotropic contributions . exchange constants along the rungs and legs of the ladder have been determined by use of inelastic neutron scattering ( ins ) as @xmath22 k and @xmath23 k , respectively ( @xmath24 ) @xcite . the ladders are coupled via very weak exchange interactions , @xmath25 mk @xcite , resulting in a transition into a field - induced magnetically ordered phase at temperatures below @xmath26 k @xcite . in a strong - leg ladder , the transverse interchain interaction couples two spin chains . as a result , two spinons are confined to magnons , opening a spin gap in the excitation spectrum . in the presence of a magnetic field the gap in dimpy closes at a critical field @xmath27 t , where the system undergoes a transition into the gapless tll phase @xcite . above @xmath28 t , the system is in the magnetically saturated spin - polarized phase @xcite . inelastic neutron scattering experiments revealed the presence of several gapless continua as well as a number of gapped excitations in dimpy @xcite ; some of the excitations have been interpreted theoretically . investigating the field - induced evolution of the magnetic excitation spectrum of a strong - leg ladder in the tll state is of particular interest , so far not covered in detail by theory and experiments . such a study would allow to obtain a better understanding of peculiarities of the spin dynamics in a strong - leg ladder in the tll phase , which is , as shown below , rather different from that known for quantum spin-1/2 chains and strong - leg ladders . esr experiments were performed at the dresden high magnetic field laboratory ( hochfeld magnetlabor - dresden ) , using transmission - type esr spectrometers ( similar to that described in ref . @xcite ) equipped with @xmath29 t superconducting and @xmath30 t pulsed - field @xcite magnets . vdi modular transmitters ( product of virginia diodes inc . , usa ) and backward - wave oscillators ( po istok , russia ) were employed as sub - mm radiation sources . high - quality single - crystal samples of dimpy with typical sizes of @xmath31 were used in our experiments . the magnetic field was applied along the @xmath32 axis . in our experiments 2,2-diphenyl-1-picrylhydrazyl ( dpph ) with @xmath33 was used a standard esr marker . a single resonance line ( mode a , fig . [ spectra ] ) was observed at temperatures above @xmath34 k. at lower temperatures , the esr spectrum undergoes remarkable changes . in addition to mode a we detected a relatively broad resonance absorption line ( mode b , fig . [ spectra ] ) . with decreasing temperature , mode b becomes more intensive and narrower , shifting towards higher fields . corresponding examples of the esr spectra as well as the dependences of esr linewidth ( mode b ) on temperature and magnetic field are shown in fig . [ spectra ] and fig . [ width ] , respectively . ( color online ) left panel : examples of esr spectra obtained at a frequency of 324 ghz at 1.5 , 2 , 2.8 , and 4.6 k. right panel : examples of pulsed - field esr spectra obtained at the frequencies 189 , 235 , 280 , and 314.4 ghz ( @xmath35 k).,scaledwidth=50.0% ] ( color online ) ( a ) temperature dependence of the linewidth of mode b at a frequency of 328.8 ghz . ( b ) linewidth of mode b for different values of resonance fields ( @xmath35 k ) . lines are guides to the eye . , scaledwidth=50.0% ] the frequency - field diagram of the magnetic excitations in dimpy is shown in fig . [ ffd ] . mode a ( white boxes in fig . [ ffd ] ) can be described using the equation @xmath36 , where @xmath37 is the planck s constant , @xmath38 is the excitation frequency , and @xmath39 . mode b ( white circles in fig . [ ffd ] ) has a more complex behavior : this mode is gapped for all fields and has a non - linear frequency - field dependence . from the extrapolation of the frequency - field dependence to zero field , the energy gap , @xmath40 ghz , can be estimated . this value agrees well with the size of the gap between the spin - singlet ground and first - excited triplet states observed by means of ins in zero magnetic field at @xmath41 @xcite , where the system is in the gapped spin - liquid state . ( color online ) the frequency - field diagram of magnetic excitations in dimpy . data of the structure factors @xmath42 and @xmath43 obtained by use of exact - diagonalization calculations for chains from @xmath44 to @xmath45 sites are given in bright colors @xcite . blue and red solid lines are guides to the eye . first and second critical fields are denoted by vertical dashed lines . , scaledwidth=50.0% ] it is worth mentioning that the esr excitation spectrum in dimpy is very different from that in the strong - rung spin ladder bpcb @xcite , where only one gapless mode was observed in the tll phase . the comparison of our esr data with results of ins studies and ed calculations for dimpy in the tll regime @xcite strongly suggests that the observed esr mode a corresponds to magnetic excitations in the @xmath43 channel , while mode b corresponds to esr excitations in the channel @xmath42 , which are nominally forbidden in the purely isotropic case . to demonstrate that @xmath42 indeed gives rise to mode b , we calculated the field dependence of the dynamical structure factor employing ed of the model ( [ ham ] ) , where the anisotropic contribution @xmath46 has been omitted . we used the parameters @xmath47 , @xmath48 k , and @xmath49 as determined above from the frequency - field dependence of mode a @xcite . the transverse dynamical structure factor @xmath43 in the symmetric channel of the legs and the longitudinal dynamical structure factor @xmath42 in the antisymmetric channel are calculated for finite systems of up to @xmath50 sites using the expression @xmath51 for @xmath52 , where @xmath53 are the eigenstates with energy @xmath54 ( @xmath55 is the ground state ) . @xmath56 is a lorentzian broadening that we set to @xmath57 . the fourier - transformed spin operators are given by @xmath58 thus , @xmath59 is the momentum perpendicular to the ladder , while we have assumed zero momentum along the ladder direction , as is common for esr . we exploit the conservation of total @xmath60 of the model ( [ ham ] ) . when the dimension of the subspace is sufficiently small , we use full diagonalization to evaluate ( [ eq : ssum ] ) while for bigger dimensions we use first the lanczos algorithm @xcite to find the ground state @xmath55 and then a continued - fraction expansion @xcite to obtain the spectral function ( [ eq : ssum ] ) . our ed results for the zero - temperature dynamical structure factors @xmath43 and @xmath42 are shown as intensity plots in fig . [ ffd ] . finite - size effects are strongest for low magnetic fields where they may amount to errors of up to 50 ghz for mode b @xcite . for magnetic fields @xmath61 t , the main finite - size effects are the steps observed in `` line '' b and thus one may estimate them to not exceed 10 ghz here . the agreement of the position of the intensity maxima for @xmath62 t with the experimental esr and ins @xcite data is excellent , including not only the downward slope , but also the curvature of mode b. we note further that application of ed to finite temperature @xcite also reproduces the qualitative trends observed in fig . [ spectra ] and fig . [ width ] ( a ) , in particular a substantial thermal broadening of mode b. as mentioned , esr transitions corresponding to mode b are nominally forbidden in the purely isotropic case . on the other hand , fig . [ fig : structure ] shows that there is no inversion center on bonds along the ladder legs in the crystal structure of dimpy and successive tetrabromocuprate units are related by unit cell translations @xcite . this allows for the presence of a uniform dzyaloshinskii - moriya ( dm ) interaction along the legs of the form @xmath63 . it is important to mention that the uniform dm interaction has been found responsible for a number of unusual effects , including , e.g. , broadening of resonance line a , observed in dimpy by means of low - frequency esr spectroscopy @xcite and the zero - field gap opening in the triangular - lattice antiferromagnet cs@xmath2cucl@xmath3 @xcite . on the other hand , such a term accounts for the intensity of mode b , that is directly proportional to the spin - spin correlations as discussed above @xcite . in the low - field limit , mode b can be described using the non - abelian bosonization approach @xcite , where it is understood as a complex of two majorana fermions @xcite . the magnetic field couples symmetrically to the two legs of the ladder whereas the majorana fermions are antisymmetric under the exchange @xmath64 of the two legs . thus , to first approximation , mode b is not affected by the applied field . this accounts for the almost flat behavior of mode b observed in fig . [ ffd ] up to about 15 t @xcite . at higher magnetic fields , renormalization effects of these majorana fermions are more important , resulting in the observed non - linear frequency - field dependence of mode b. our observations of the @xmath42 mode can have broader impact in the context of the @xmath65(5 ) ladder model @xcite . in this model , the quantum phase transition driven by the chemical potential can be mapped to the field - induced phase transitions in the heisenberg ladder . in that case , the gapless excitations in the tll state of spin ladders ( mode a ) are interpreted as massless @xmath66 bosons , while the gapped excitations ( mode b ) correspond to massive @xmath67 bosons @xcite . the former contribution is characteristic of the tll state and is commonly found in spin-1/2 heisenberg chains ( and can be interpreted as originating from the bose condensate of @xmath68 magnons ) , while the latter have @xmath69 magnons as their origin . the boson mass is determined by the luttinger constant @xmath70 ( describing the nature of interactions between particles ) and the velocity @xmath71 ; both parameters are field dependent @xcite . the complex contributions of these two variables to the gapped excitation give a hint for understanding the non - linear dependence of mode b in a magnetic field as observed in our experiments . to summarize , the excitation spectrum in dimpy , a spin-1/2 heisenberg antiferromagnetic strong - leg ladder compound , was probed by means of high - field esr in magnetic fields up to 50 t. two esr modes were observed . one of them has a linear frequency - field dependence , and corresponds to zeeman - split massless @xmath72 excitations , commonly found in spin-1/2 heisenberg chains and strong - rung ladders in the tomonaga - luttinger liquid regime . on the other hand , we show that a key property of the esr spectrum in a spin-1/2 heisenberg strong - leg ladder in the tll phase is the presence of gapped @xmath42 excitations that derive from the gapped @xmath69 boson . good agreement between results of exact - diagonalization calculations and the experimental data was demonstrated . this work was partially supported by the helmholtz gemeinschaft via the virtual institute `` new states of matter and their excitations '' , deutsche forschungsgemeinschaft ( dfg , germany ) , swiss snf under division ii , and erc synergy uquam project . we acknowledge the support of the hld at hzdr , member of the european magnetic field laboratory ( emfl ) .

several microscopic scenarios have been proposed as underlying mechanisms for dynamical arrest in supercooled liquids @xcite . because this dramatic slowing down is accompanied by the onset of dynamical heterogeneity@xcite , a promising candidate model should account for the spontaneous segregation of rapidly relaxing and slowly relaxing domains . the theory of frustration - limited domains has been developed with this condition in mind@xcite . the basic units of this theory are microscopic regions of low internal energy whose spatial extent is limited by long - ranged interactions or constraints . nelson and coworkers suggested that such domains form in simple `` atomic '' liquids ( such as metallic glass - formers)@xcite . for small clusters of particles , icosahedral arrangements are energetically preferred over closest - packed configurations representative of the crystalline state@xcite . it is thus argued that a supercooled atomic liquid is rich in low - energy icosahedral clusters which , for geometric reasons , can not extend indefinitely . in this case , frustration is a consequence of the vanishing curvature of euclidean space . one can imagine that the nature of local order and source of frustration are somewhat different for other , more complicated materials . the frustration - limited domain theory has several attractive features . by associating relaxation kinetics with the interfacial area of domain walls , it predicts a crossover in the temperature dependence of structural rearrangement times from arrhenius to a super - arrhenius form . such a crossover is prominent in experiments with fragile glass - formers@xcite . further , the theoretical scaling exponent for the asymptotic super - arrhenius temperature dependence appears to be consistent with experimental data . finally , the notion of frustration - limited domains resonates with the picture of heterogeneous dynamics that has emerged from experiments@xcite and simulations@xcite . while local structure within low - energy clusters may be effectively frozen on a molecular time scale , relaxation can be facile at the strained interfaces between domains . this argument is the essence of stillinger s `` tear and repair '' picture of shear flow in fragile liquids@xcite . although these dynamical predictions of frustration - limited domain theory are suggestive , they are fundamentally thermodynamic in nature and thus indirect . in order to make such arguments precise , grousson _ have recently focused on the explicit dynamics of minimal models exhibiting frustration - limited domains@xcite . specifically , they have simulated stochastic dynamics of several classical spin models that pit short - ranged , ferromagnetic interactions against long - ranged , antiferromagnetic interactions . in addition to confirming super - arrhenius relaxation for these models at low temperatures , they have demonstrated that the `` fragility '' of the dynamics ( i.e. , the degree of deviation from arrhenius form ) varies continuously with the relative strength of the long - ranged frustration . quite recently , grousson _ have performed dynamical mode coupling calculations for the same models , but no direct comparisons to their earlier simulations were made@xcite . in this paper , we perform similar calculations that are compared directly to numerical simulations . schmalian and coworkers have also argued that such a coulomb - frustrated ferromagnet should display essential features of glassy dynamics@xcite . in their analysis , it is a proliferation of metastable states that drives vitrification . with the aid of replica mean field theory , this perspective predicts a scaling of fragility with frustration strength that agrees well with the simulation results of ref.@xcite . but like the theory of frustration - limited domains , this analysis is _ thermodynamic _ in nature , relying on an assumed correspondence between particular subensembles of high free energy and genuine dynamical bottlenecks . this paper addresses the extent to which the slow relaxation in such simplified models truly resembles that of molecular glass - forming liquids . for this purpose we investigate in detail the _ dynamics _ of a model closely related to those studied in refs.@xcite and @xcite . the model and dynamical propagation rules we consider , which are free of artificially quenched disorder and kinetic constraints , are described in sec . 2 . for several values of the frustration strength , we compare the time dependence of spin correlations computed in simulations with those predicted by approximate theoretical approaches . two self - consistent dynamical equations obtained from theory are discussed in sec . they correspond to resummations of an exact , infinite diagrammatic series for time correlations . the first resummation , yielding exponential relaxation at each wave vector , is a direct dynamical generalization of brazovskii s static result for this class of models@xcite . calculations based on this straightforward approach agree remarkably well with simulation results , described in sec . 4 , even for temperatures approaching a thermodynamic transition to a fully ordered state . the second resummation is formally analogous to the idealized mode coupling theory of liquids . as such , it predicts loss of ergodicity at finite temperature . by contrast , we find no evidence of nonergodic behavior or two - step relaxation for simulated disordered states of this model . surprisingly , then , the hartree approach is the more accurate approximation for slowly relaxing disordered states of the model system . detailed comparison of simulation and theory confirms that sluggishness indeed arises from de gennes narrowing ( i.e. , from dramatic changes in static correlations ) , in contrast to complex dynamical mechanisms such as mode coupling . in this respect , the minimal model we have studied does not capture important aspects of supercooled liquid dynamics , specifically the intermediate time plateau and long time stretching of dynamical correlators . implications of this result are discussed in sec . 5 , along with issues related to fragility and local conservation of magnetization . in section 6 we conclude . we consider fluctuations of a field @xmath0 at position @xmath1 in three dimensions , with energy@xcite @xmath2 = \nonumber \\ & & \int d{\bf r } \ , \left[\phi({\bf r } ) \left(\tau + k_0^{-2}(\nabla^2 + k_0 ^ 2)^2\right ) \phi({\bf r } ) + { \lambda \over 4!}\phi^4({\bf r})\right ] . \label{equ : hamiltonian}\end{aligned}\ ] ] here , the energy scale @xmath3 characterizes typical fluctuations of a surrounding heat bath . the physical meaning of the field @xmath4 may be somewhat abstract in the context of supercooled liquids , for example representing the degree of a particular local packing symmetry . the application of eq . [ equ : hamiltonian ] to diblock copolymer melts is more intuitive@xcite . in this case , @xmath4 represents the local excess number density of one monomer type , and @xmath5 describes the preferential affinity of monomers for others of the same type . because our interest in this model is motivated by the work in ref.@xcite , we will imagine that @xmath4 simply represents a coarse - grained , scalar spin density . here , @xmath5 is a dimensionless temperature measuring the distance from an underlying critical temperature when @xmath6 . for any physical interpretation , the wave vector @xmath7 characterizes long - ranged order of a low - temperature , microphase separated state . the coefficient @xmath8 multiplying the @xmath9 term in eq . [ equ : hamiltonian ] will later be used to order terms in perturbation series , although in calculations its numerical value will be of order unity . for wave vectors near @xmath10 , the action in eq . [ equ : hamiltonian ] corresponds to that studied by schmalian and wolynes @xcite and ( in a hard - spin lattice version ) by grousson _ et al._@xcite . in their work , frustration is explicit in competing interactions of square - gradient ( @xmath11 ) and coulomb ( @xmath12 ) forms . the relative strengths of these interactions determine the periodicity of the ground state , @xmath13 , in which spin - up and spin - down domains alternate in stripes or lamellae@xcite . in the model defined by eq . [ equ : hamiltonian ] , this frustration is instead implicit in nonzero @xmath10 , but has the same physical effect . namely , homogeneous domains are energetically favored at small length scales , while net magnetization is effectively constrained to vanish at larger length scales . in the context of diblock copolymers , this effective constraint reflects the stoichiometry imposed by polymer connectivity@xcite . in two dimensions and higher , the presence of nonzero @xmath10 in eq . [ equ : hamiltonian ] has a subtle but profound effect on the thermodynamics of the paramagnetic state . specifically , the large entropy of fluctuations near @xmath14 significantly reduces the free energy of the disordered phase . within a hartree approximation , this contribution is sufficient to make the paramagnetic state stable or metastable for all finite @xmath5 . as a consequence , the transition to a phase with long - ranged order is first ( rather than second ) order and occurs at a temperature @xmath15 . this effect was first recognized by brazovskii@xcite and has been summarized lucidly by binder and fredrickson@xcite . its qualitative features have been subsequently confirmed in experiments with diblock copolymers@xcite . because , in this picture , statistics of the disordered state are dominated by fluctuations near @xmath10 , we expect the model of eq . [ equ : hamiltonian ] to belong to the same universality class as those of refs.@xcite and @xcite . later , we will demonstrate that slow dynamics of this state are dominated by the very same fluctuations . the action in eq . [ equ : hamiltonian ] is not a true hamiltonian , and thus has no intrinsic dynamics . we consider two commonly used stochastic propagation rules which generate a canonical ensemble of fluctuations consistent with eq . [ equ : hamiltonian ] . attention will be primarily focused on a simple langevin equation , @xmath16 \over{\delta \phi({\bf r } ) } } + \eta({\bf r},t ) , \label{equ : langevin}\ ] ] where @xmath17 is a random force whose statistics are gaussian , and @xmath18 in eq . [ equ : noise ] , angled brackets denote an average over all possible realizations of the random force . the above equation of motion , along with the energetics of eq . [ equ : hamiltonian ] and the statistics of eq . [ equ : noise ] , has been studied previously , most notably in the context of nucleation and nonequilibrium pattern formation following a rapid quench to @xmath19@xcite . to our knowledge , the detailed equilibrium dynamics of the paramagnetic phase very close to the transition ( i.e. , @xmath20 ) have not until now been fully explored . the dynamics generated by eq . [ equ : langevin ] do not conserve the field @xmath21@xcite . because the slow relaxation of supercooled liquids results in part from the conservation of hydrodynamic densities , this feature of eq . [ equ : langevin ] may be somewhat troubling ( particularly in the context of diblock copolymers , in which the number density is clearly conserved ) . for this reason , we consider a second form of dynamics that conserves @xmath21 by construction . trajectories of this dynamics are chains of microstates generated by a metropolis monte carlo algorithm . in detail , a random displacement of the field @xmath0 is attempted at discrete time steps , and is accepted with probability @xmath22 , \label{equ : mc}\ ] ] where @xmath23 is the change in energy produced by the displacement . local conservation of the field is achieved by restricting the choice of random displacements to those which do not alter the local net magnetization . further details of this procedure will be described in sec . simulation results presented in that section demonstrate that the decay of spin correlations produced by eqs . [ equ : langevin ] and [ equ : mc ] are nearly identical , within an arbitrary rescaling of time in the monte carlo chain of states . the physical meaning of this fact will be discussed in sec . in this section we discuss two approximations for relaxation of the field @xmath21 . specifically , we derive closed equations of motion for the correlation function @xmath24 where fourier components of the field are defined in the standard way : @xmath25 the first equation of motion is linear in @xmath26 and resembles phenomenological theories of high temperature liquid state dynamics , such as the wave vector dependent viscoelastic theory@xcite . the second is nonlinear and has the form of the idealized mode - coupling approximation to the dynamics of density fluctuations in supercooled liquids@xcite . this equation contains the feedback mechanism responsible for the interruption of particle diffusion at intermediate time scales due to constraints imposed by slowly reorganizing local environments ( the `` cage '' effect ) . treating @xmath8 as a perturbation parameter , the solution to eq . [ equ : langevin ] may be written as an infinite series of terms , each representing a collection of field interactions and periods of free propagation . as a result , @xmath27 and its associated response function , @xmath28 can be expanded in powers of @xmath8 . ( we focus exclusively on the portion of the phase diagram in which dynamics are ergodic , so that @xmath29 and @xmath30 are related by the fluctuation - dissipation theorem . ) [ fig : diagrams ] shows diagrammatic representations of the first two terms in the series for @xmath27 . the development of this expansion , as well as the partial series resummations underlying our approximations , have been discussed thoroughly in the context of other models . we will describe physically significant highlights of the procedure and refer the reader to refs.@xcite for details . a linear equation of motion for @xmath27 results from summing only terms in the series whose diagrams have the basic topology shown in fig . [ fig : diagrams](a ) . in the irreducible segments of these `` tadpole '' diagrams , all interactions coincide in time . consequently , such a summation renormalizes only the static portion of the basic tadpole diagram of fig . [ fig : diagrams](a ) . the dynamics predicted by this hartree resummation scheme are identically those of a variationally optimized harmonic reference system@xcite . they are thus obtained more directly by assuming gaussian statistics for @xmath31 . specifically , we multiply the fourier transform of eq . [ equ : langevin ] by @xmath32 and average over the noise history , yielding @xmath33 c_{\bf k}(t ) + \nonumber \\ & & { \lambda \over 3 ! } \sum_{{\bf k}',{\bf k } '' } \langle \phi_{{\bf k}'}(t ) \phi_{{\bf k}'}(t ) \phi_{{\bf k}-{\bf k}'-{\bf k}''}(t ) \phi_{-{\bf k}}(0 ) \rangle . \label{equ : avlang}\end{aligned}\ ] ] eq . [ equ : avlang ] is the first member of a complicated hierarchy of equations relating multi - point fluctuations to correlations of higher order . but if we assume that @xmath31 is a gaussian random variable , the hierarchy closes immediately : @xmath34 here , the renormalized mass @xmath35 that appears in the expression for the structure factor @xmath36 is determined self - consistently by @xmath37 this result is precisely brazovskii s static approximation@xcite . the relaxation described by eq . [ equ : hartree ] , while simply exponential , occurs with rates that are significantly renormalized by the entropy of fluctuations near @xmath38 . more elaborate , nonlinear approximations for @xmath27 result from incorporating diagrams with more complicated topologies@xcite . the mode coupling approximation ( mca ) is an example , including diagrams with the `` sunset '' shape of fig . [ fig : diagrams](b ) . summing all terms that renormalize the propagators ( but not the vertices ) of the basic sunset diagram yields the mca . because these contributions involve more than one unique time variable , they are capable in principle of capturing nontrivial memory effects . as shown in ref.@xcite , the self - consistent result of this resummation is @xmath39 \frac{\partial c^{\rm mca}_{\bf k}(t')}{\partial t^{'}}. \label{equ : mca}\end{aligned}\ ] ] the final , nonlinear term of eq . [ equ : mca ] explicitly couples the dynamics of fluctuations at different wave vectors , so that the decay of @xmath40 is not simply exponential . the mode - coupling estimate of the static structure factor , @xmath41 , is determined by a self - consistent equation involving both the `` tadpole '' and `` sunset '' diagrams . we avoid this static calculation by instead replacing @xmath42 in eq . [ equ : mca ] with the exact form of @xmath43 from numerical simulations . this procedure is commonly employed in mode - coupling studies of supercooled liquids . as the microphase transition point is approached from high temperature , we expect that only modes near the ordering wave vector @xmath44 will remain important . in this regime , a reduced model without reference to the coupling of specific length scales should capture the qualitative behavior of eq . [ equ : mca ] . such a schematic model is similar to that studied by leutheusser for structural glass - forming liquids@xcite . ( indeed , eq . [ equ : mca ] is only slightly different from that encountered in the idealized mode - coupling theory of supercooled liquids@xcite . in particular , the memory kernel involves a two - point correlation function raised to the third , rather than second , power . ) restricting attention to @xmath14 , and neglecting coupling to other wave vectors , eq . [ equ : mca ] reduces to the dynamical equation exactly describing the @xmath45-spin model of a mean field spin glass ( with @xmath46 ) . since for @xmath47 the critical properties of such models are essentially @xmath45-independent , we expect that near a critical point , eq . [ equ : mca ] will exhibit a plateau and an eventual transition to nonergodic behavior@xcite . the character of the slow dynamics resulting from the theories underlying eq . [ equ : hartree ] and eq . [ equ : mca ] are fundamentally different . the dynamical hartree theory ( eq . [ equ : hartree ] ) may exhibit a rapid slowing of dynamics as a function of inverse temperature _ only _ if the statics , as expressed through the renormalized mass @xmath35 , are strongly temperature dependent . on the other hand , due to the nonlinearity of eq . [ equ : mca ] , a slight change in the structure factor may result in a dramatic change in relaxation times . it is well known that glass - forming liquids show little change in static structure as the glass transition is approached@xcite . thus , theories of the type given in eq . [ equ : hartree ] are not relevant near the glass transition . in the following sections , the predictions of eq . [ equ : hartree ] and eq . [ equ : mca ] will be compared with simulations for the coulomb - frustrated system . the renormalized perturbation theories developed in this section are strictly valid only in the limit of weak coupling , i.e. , for small @xmath8 or large , positive @xmath5 . in our simulation work , we fix @xmath48 . it is thus instructive to ask at what value of @xmath5 these theories are expected to break down . to answer this question , we follow the arguments of hohenberg and swift@xcite . specifically , we compare the hartree approximation to the renormalized mass , @xmath35 , with corrections introduced by mode coupling ( i.e. , the renormalized sunset diagram ) . these corrections are comparatively small when @xmath49 in this regime the hartree and mode coupling approximations are controlled , and differ only quantitatively from one another . for larger @xmath50 , however , the two approximations can differ substantially , as we will see in numerical results presented in the following section . it has been noted previously that the static hartree approximation can be accurate beyond its strict range of validity . there is thus no guarantee that a range of @xmath5 exists in which the mode coupling approximation significantly improves upon an appropriately chosen harmonic reference system . in order to follow the dynamics of eq . [ equ : langevin ] or eq . [ equ : mc ] numerically , it is necessary first to coarse - grain the field @xmath21 in space . this procedure yields a ( periodically replicated ) finite set of dynamical variables , whose time evolution may be integrated approximately over short intervals . we select a coarse - graining length @xmath51 , and define new fields at lattice points @xmath52 : @xmath53 where @xmath54 is bounded by a cube of side length @xmath55 centered at @xmath56 . in the calculations described below , @xmath57 , so that a domain of wavelength @xmath58 comprises several `` soft spins '' @xmath59 . to lowest order in @xmath55 and a small time increment @xmath60 , these renormalized fields evolve according to @xmath61 + \overline{\eta}_i(t ) . \label{equ : discrete}\end{aligned}\ ] ] here , the lattice approximation to the laplacian operator acting on a function of space , @xmath62 , is taken to include a sum over nearest neighbors only ( denoted nn ) . after coarse - graining , statistics of the random force remain gaussian , with @xmath63 . the simulation algorithm described above ( which is very similar to those of refs.@xcite ) has several advantages over the numerical approach of ref.@xcite , which employs `` hard spins '' ( @xmath64 and explicit frustration . first , spins interact only with nearest and next - nearest neighbors , providing linear scaling of computational effort with system size . because cumbersome techniques associated with long - ranged forces are not required , a larger set of dynamical variables may be considered . in our calculations , the periodically replicated unit cell includes @xmath65 spins arranged on a cubic lattice . more importantly , the coarse - graining procedure allows the dimensions of the unit cell to scale with the physically relevant length @xmath66 . as a result , the unit cell spans several correlation lengths , even for very small values of @xmath10 . by contrast , in the work of ref.@xcite , the unit cell is comparable to a single natural lamellar spacing for several of the simulated states ( particularly those corresponding to `` fragile '' systems ) . in those cases , significant finite size effects are possible . in effect , grousson _ _ cut off slowly relaxing fluctuations at small @xmath67 rather than the rapidly relaxing fluctuations at large @xmath68 that are integrated out in our approach . in sec . 5 we discuss the dynamical implications of such a cutoff . using eq . [ equ : discrete ] , we have computed the dynamics of several states of the model system at temperatures above the microphase separation transition ( @xmath20 ) . we focus on three values of @xmath10 ( 0.1 , 0.5 and 1.0 ) corresponding to a somewhat broader range of model parameters than was considered in ref.@xcite . in each case , @xmath48 , so that the microscopic dynamics is in principle strongly nonlinear . representative configurations of the system are depicted in fig . [ fig : pics ] , typifying the high - temperature paramagnetic phase ( a ) , the disordered phase near the microphase separation transition ( b ) , the ordered lamellar phase ( c ) , and a nonequilibrium state produced by rapid quenching of a disordered system to low temperature ( d ) . for each value of @xmath10 we consider , the relaxation of spin correlations slows dramatically near the transition to microphase separation . the time required for single - spin correlation , @xmath69 to decay to @xmath70 of its initial value , @xmath71 , is plotted as a function of @xmath5 in fig . [ fig : relax ] . the growth of relaxation times as @xmath5 approaches @xmath72 is sharpest for the smallest value of @xmath10 . indeed , critical fluctuations are suppressed least strongly in this case , as evidenced by the onset of sluggishness very near @xmath73 . grousson _ et al . _ have likened systems corresponding to large and small values of @xmath10 to `` strong '' and `` fragile '' glass formers , respectively@xcite . for fragile cases , they have even shown that the temperature dependence of @xmath71 is well fit by the vogel - fulcher form found for supercooled liquids . although this functional form suggests an emerging importance of activated processes , the dramatic growth of relaxation times is in fact well captured by the harmonic reference system described in sec . 3 . numerical solutions of eq . [ equ : braz ] ( plotted as solid lines in fig . [ fig : relax ] ) , corresponding to this hartree approximation , are especially accurate in the most fragile case ( @xmath74 ) . even for the least fragile case ( @xmath75 ) , computed rates differ from predicted values by at most a factor of two . activated barrier crossing is manifestly absent on a harmonic landscape , strongly implying that slow dynamics are driven by static renormalization , rather than by fundamental changes in the structure of trajectory space@xcite . the static structure factor , @xmath76 , in fact becomes more sharply peaked in a way that mirrors the sudden growth in @xmath71 . in other words , the slowing of relaxation appears to be an example of de gennes narrowing@xcite . the time dependence of spin correlations provides further evidence for this interpretation . specifically , even when relaxation is very slow , correlations decay nearly exponentially at each wave vector . in fig . [ fig : ckt ] , @xmath27 is plotted for many @xmath77 values for a system very near microphase separation ( @xmath78 , @xmath79 ) . included wave vectors span a range from the lowest accessible spatial frequency ( @xmath80 ) to several multiples of @xmath10 . in no case is relaxation detectably caged or stretched at long times . the single - spin correlation function , @xmath81 , in eq . [ equ : ct ] is a superposition of all @xmath27 , and thus does not decay as a single exponential . at long times , however , relaxation is dominated by the slowest modes , those with wave vectors lying in a spherical shell with @xmath82 , and is very nearly exponential . since static correlations are strongest for these modes , especially near the microphase separation transition , @xmath81 is nonexponential only over a small range of the total decay . remarkably , spin relaxation is essentially identical for a very different choice of microscopic propagation rules which conserve the field @xmath83 . in this monte carlo dynamics , described in sec . 2 , each trial move simultaneously displaces @xmath83 at a randomly chosen site @xmath84 and at a a site @xmath85 randomly chosen from the nearest neighbors of @xmath84 . the displacement at @xmath84 , @xmath86 , is exactly compensated by that at @xmath85 , i.e. , @xmath87 . in this way , @xmath83 is conserved at all length scales greater than or equal to the lattice spacing @xmath55 . in general , such a constraint can influence dynamical behavior dramatically . for instance , scaling exponents for unstable domain growth in similar models depend intimately on the conservation of order parameters@xcite . the relaxation described above , however , is modified by the constraint only at very short times . the insensitivity of slow dynamics to field conservation in this model was anticipated by sachdev , who noted that the corresponding constraint couples strongly only to fluctuations with very small wave vector ( @xmath88)@xcite . the long - lived correlations in fig . [ fig : ckt ] , however , are governed not by these modes , but instead by fluctuations of finite wave vector ( @xmath89 ) , which couple relatively weakly to the constraint . conservation is thus of only modest importance at long times in the _ disordered _ phase . these facts can lead in principle to dramatic finite size effects in numerical simulations . specifically , the smallest periodically replicated unit must accommodate fluctuations with wavelengths several times @xmath10 . otherwise , the absence of truly long wavelength fluctuations will generate spuriously strong coupling of conservation constraints to the slowest accessible modes . as a result , artificial dynamical features may appear at long times . for model energetics that are similar to but different from eq . [ equ : hamiltonian ] , stretched exponential relaxation has been computed from simulations in which system dimensions are comparable to @xmath66@xcite . to the extent that fluctuations near @xmath14 are independent of model details , such anomalous dynamics should not survive in the thermodynamic limit . the persistence of exponential relaxation into the neighborhood of microphase separation , obtained numerically both for langevin and monte carlo dynamics , is consistent with the dynamical hartree approximation described in sec . 3 . in fact , this simple theory also predicts with remarkable accuracy the time scales of relaxation , even as they grow by several orders of magnitude . results for the case @xmath90 are compared in fig . [ fig : hartree ] by plotting @xmath91 obtained from theory and simulation for several values of @xmath5 . the success of the harmonic reference system provides further evidence that `` vitrification '' in this model is driven by dramatic changes in structural order rather than novel relaxation mechanisms . indeed , several dynamical features that would seem to be related to activated barrier crossing may be well rationalized in the hartree picture . for example , the fragility parameter defined empirically by @xmath92 appears to scale as @xmath93 in the simulations of ref.@xcite . here , @xmath94 is a fitted kauzmann temperature at which relaxation times appear to diverge . schmalian and wolynes have suggested that this scaling arises from the entropy of activation for structural rearrangement of mesoscopic domains@xcite . the hartree approximation offers a simpler explanation . fitted relaxation times follow @xmath95 rather well . it is easy to show by dimensional scaling that the renormalized mass is a function only of @xmath96 , yielding immediately @xmath97@xcite . this slightly different scaling form fits the results of grousson _ et al . _ equally well@xcite . for the simulations of larger systems we have presented , the hartree prediction appears to be superior . the dynamical scenario predicted by the simplified mode coupling theory of sec . 3 , on the other hand , is not borne out in our simulations . most significantly , we observe neither loss of ergodicity nor two - step relaxation over the relevant range of @xmath98 . these failures of the dynamically nonlinear approximation are evident in fig . [ fig : mca ] , comparing the mca and simulation results for the same system and thermodynamic states considered in fig . [ fig : hartree ] . interestingly , the mca predicts trapping at values of @xmath5 for which the hartree approximation remains reasonable . the infinite series of terms incorporated in the mode coupling approximation thus adds little realism to the lower order description , and eventually leads to incorrectly anomalous behavior . this series of terms must be compensated to a large degree by omitted terms at each order . there have been suggestions that similar cancellation occurs in mode coupling expansions of supercooled liquid dynamics@xcite . in that case , however , signatures of idealized mode coupling ( i.e. , two - step relaxation ) survive despite the existence of omitted relaxation channels . in our model , no such signatures are evident . we emphasize that the thermodynamic states we have simulated lie exclusively in the disordered phase of our model system . we have confirmed this fact by computing the work to reversibly impose long - range order ( i.e. , nonzero @xmath99 at @xmath14 ) . although the static hartree approximation suggests that the states of lowest temperature considered for each @xmath10 have global free energy minima in ordered configurations , the computed free energy of the paramagnetic state is in fact lower for each case . this quantitative failure of brazovskii s approximation is not surprising , as the relevant states lie outside the strict range of validity of the approximation for @xmath48@xcite . our analysis thus leaves unexplored a narrow window of the disordered state extremely close to @xmath100 . while it is possible that qualitatively new dynamical behavior arises in this region , it can not account for the dramatic slowing down we have demonstrated at higher temperature , which is driven by extreme structural changes rather than activated processes . furthermore , the sudden onset of nontrivial behavior would be in stark contrast to the more gradual onset of caging and stretched exponential behavior in real liquids . we have examined in detail a simple model that is closely related to the frustration - limited domain theory of kivelson , tarjus and coworkers@xcite , and to the uniformly frustrated `` stripe - glass '' model studied by schmalian and wolynes@xcite . the disordered phase of this model system indeed displays some hallmarks of molecular glass - forming liquids . but its dynamics differ qualitatively from generic glassy behavior in several respects . while relaxation times increase dramatically in these models in a non - arrhenius fashion as temperature is lowered , we find that an optimized harmonic reference system captures the time dependence of fluctuations semi - quantitatively . in contrast to the vitrification of molecular liquids , the onset of this sluggishness is _ not _ accompanied by significant power law or stretched exponential decay of correlations in time . perhaps most importantly , we find that the the slow decay of dynamical correlations is driven by significant changes in static structure . an idealized mode - coupling theory captures these changes less accurately than the simpler harmonic approach , predicting caging and eventual trapping at temperatures where the simulated dynamics remain exponential and ergodic . together , these results strongly suggest that slow dynamics of this model system arise from the same gaussian fluctuations that drive the microphase separation transition first order . this conclusion differs markedly from those of kivelson _ et al._@xcite , grousson _ et al._@xcite , and of schmalian and wolynes@xcite , which invoke activated barrier crossing to explain the dramatic temperature dependence of relaxation times . uniform frustration alone thus appears insufficient to account for the unusual relaxation properties of supercooled liquids . it remains possible , of course , that such frustration plays a key role , but in concert with other important physical mechanisms and constraints . the simulations described in this paper constitute a thorough study of the thermodynamically disordered phase of a uniformly frustrated model . they raise some interesting questions about such models and leave others unaddressed . in particular , while glassy behavior is not manifest for @xmath20 , we can not rule out the existence of caging or trapping extremely close to or below the microphase separation temperature ( since relaxation at these temperatures is prohibitively slow ) . to explore this possibility , we have simulated several initially disordered states with @xmath101 . their nonequilibrium evolution towards long - ranged order exhibits the self - similar aging characteristic of coarsening phenomena , but for numerically accessible time scales does not resemble the relaxation of a supercooled liquid . nonexponential equilibrium relaxation could yet emerge at temperatures above but _ very _ near the order - disorder transition@xcite . eastwood and wolynes have in fact recently suggested that , for certain spin models , surface tension effects drive the onset of activated dynamics nearly to the ideal glass transition temperature@xcite . although quite interesting , such behavior would itself be uncharacteristic of glass - forming liquids , as it would appear only within an extremely narrow thermodynamic range . we would like to thank b. chakraborty , g. tarjus and p. wolynes for useful discussions . d.r.r . was supported by an nsf career award ( # 0134969 ) . is an m.i.t . science fellow . t. r. kirkpatrick and p. g. wolynes phys . a , * 35 * , 3072 ( 1987);t . r. kirkpatrick and d. thirumalai phys . rev . a , * 37 * , 4439 ( 1988);t . r. kirkpatrick , d. thirumalai , and p. g. wolynes , phys . a * 40 * , 1045(1989 ) . steinhardt , d.r . nelson , and m. ronchetti , phys . lett . , * 47 * , 1297 , ( 1981 ) ; s. sachdev , d.r . nelson , phys . rev . b , * 32 * , 4592 , ( 1985 ) ; s. sachdev , d.r . nelson , phys . b , * 32 * , 1480 , ( 1985 ) ; d.r . nelson , s. sachdev , phys . b , * 32 * , 689 , ( 1985 ) . for domain ordering of a discrete lattice system ( as opposed to a continuous field theory ) , periodicity of the ground state scales slightly differently with model parameters , @xmath102 . [ see : p. viot and g. tarjus europhys . lett . * 44 * , 423 , ( 1998 ) . ] in this case the fragility parameter of eq . [ equ : fragility ] scales as @xmath103 , which is likely the closest fit to the data of ref.@xcite .

we present simulation results for the dynamics of a schematic model based on the frustration - limited domain picture of glass - forming liquids . these results are compared with approximate theoretical predictions analogous to those commonly used for supercooled liquid dynamics . although model relaxation times increase by several orders of magnitude in a non - arrhenius manner as a microphase separation transition is approached , the slow relaxation is in many ways dissimilar to that of a liquid . in particular , structural relaxation is nearly exponential in time at each wave vector , indicating that the mode coupling effects dominating liquid relaxation are comparatively weak within this model . relaxation properties of the model are instead well reproduced by the simplest dynamical extension of a static hartree approximation . this approach is qualitatively accurate even for temperatures at which the mode coupling approximation predicts loss of ergodicity . these results suggest that the _ thermodynamically disordered _ phase of such a minimal model poorly caricatures the slow dynamics of a liquid near its glass transition .

cosmological constant @xmath4 was originally introduced in general relativity with the motivation to allow static homogeneous universe to einstein equations in the presence of matter . once expansion of the universe was discovered , its role turned out to be unnecessary and it experienced a checkered history . recent cosmological observations suggest some evidences for the existence of a positive cosmological constant @xcite : from a variety of observational sources , its magnitude is @xmath5 , and both matter @xmath6 and vacuum @xmath7 are of comparable magnitude , @xmath8 in spatially flat universe . both results are paraphrased as old and new cosmological constant problems @xcite . inclusion of quantum field theory predicts naturally the energy density via quantum fluctuations even up to the planck scale , so the old problem is to understand why the observed present cosmological constant is so small . it is the worst fine - tuning problem requiring a magic cancellation with accuracy to 120 decimal places . the new problem is to understand why the vacuum energy density is comparable to the present mass density of the universe . though there are several classes of efforts to solve the cosmological constant problem , e.g. , cancellation of vacuum energy based on symmetry principle like supersymmetry , the idea of quintessence , and the anthropic principle , any of them is not widely accepted as the solution , yet . in the early universe , existing cosmological constant also provides an intriguing idea , inflationary cosmology , to fix long - standing cosmological problems in the big - bang scenario . in addition to the above , detailed properties of the de sitter geometry in arbitrary dimensions raise a debate like selection of true vacuum compatible with its scale symmetry in relation with trans - planckian cosmology @xcite or becomes a cornerstone of a theoretical idea like ds / cft for a challenging problem of quantum gravity in de sitter spacetime @xcite . in the context of general relativity , classical study on the cosmological constant is to understand geometry of de sitter spacetime ( ds@xmath9 ) . therefore , in this review , we study de sitter geometry and the motion of classical test particle in the background of the de sitter spacetime in detail . topics include useful coordinate systems , geodesic motions , and penrose diagrams . one of our purposes is to combine knowledges of classical de sitter geometry , scattered with other subjects in the textbooks or reviews , in one note @xcite . we tried to make our review self - contained and a technical note by containing various formulas in the appendix . the review is organized as follows . in section 2 , we introduce our setup with notations and signature . in section 3 , four coordinates ( global , conformal , planar , and static ) and coordinate transformations among those are explained with the reason why such four of them are frequently used . killing symmetries are also obtained in each coordinate system . all possible geodesic motions of classical test particle are given in section 4 . identification of de sitter horizon for a static observer and cosmological evolution to a comoving observer are also included . in section 5 , causal structure of the global de sitter spacetime is dealt through penrose diagrams , and its quantum theoretical implication is also discussed . section 6 is devoted to brief discussion . various quantities are displayed in appendix for convenience . in this section , we introduce basic setup for studying classical geometry of de sitter spacetime in arbitrary dimensions . two methods are employed : one is solving directly einstein equations for each metric ansatz , and the other is reading off the specific form of coordinate transformation between two metrics . we begin with einstein - hilbert action coupled to matters : @xmath10 where @xmath11 stands for the matter action of our interest , which vanishes for limit of the pure gravity , and @xmath4 is a cosmological constant , which sets to be positive for ds@xmath9 . einstein equations are read from the action ( [ act ] ) @xmath12 where energy - momentum tensor @xmath13 is defined by @xmath14 throughout the paper small greek indices @xmath15 run from @xmath16 to @xmath17 , and our spacetime signature is @xmath18 . to be specific let us consider a real scalar field @xmath19 of which action is @xmath20.\ ] ] in order not to have an additional contribution to the cosmological constant at classical level , we set minimum value of the scalar potential to vanish , @xmath21 . then its energy - momentum tensor becomes @xmath22 where energy density @xmath23 is positive semi - definite in the limit of flat spacetime . for the pure ds@xmath9 , the energy - momentum tensor of the matter , @xmath13 , vanishes so that one can regard these spacetimes as solutions of the einstein equations of eq . ( [ eeq ] ) @xmath24 for an empty spacetime with a positive constant vacuum energy @xmath25 : @xmath26 therefore , the only nontrivial component of the einstein equations ( [ 2 ] ) is @xmath27 it means that the de sitter spacetime is maximally symmetric , of which local structure is characterized by a positive constant curvature scalar alone such as @xmath28 since the scalar curvature ( [ 4 ] ) is constant everywhere , the ds@xmath29 is free from physical singularity and it is confirmed by a constant kretschmann scalar : @xmath30 we follow usual definition of tensors as follows . [ cols="^,^",options="header " , ] when we deal with specific physics in general relativity , we are firstly concerned with appropriate coordinate system . in this section , we introduce four useful coordinates and build coordinate transformations among those for tensor calculus : they are global ( closed ) , conformal , planar ( inflationary ) , and static coordinates . for the detailed calculation of various quantities in systems of coordinates , refer to appendix . similar to physical issues in flat spacetime , the symmetries of a riemannian manifold is realized through metric invariance under the symmetry transformations . specifically , let us choose a coordinate system as @xmath31 and take into account a transformation @xmath32 . if the metric @xmath33 remains to be form - invariant under the transformation @xmath34 for all coordinates @xmath35 , such transformation is called an isometry . since any finite continuous transformation with non - zero jacobian can be constructed by an infinite sum of infinitesimal transformations , study under infinitesimal transformation is sufficient for continuous isometry . if we consider an infinitesimal coordinate transformation @xmath36 where @xmath37 is small parameter and @xmath38 a vector field , expansion of the form - invariance ( [ fin ] ) leads to killing s equations @xmath39 where @xmath40 denotes a lie derivative . then , any @xmath38 given by a solution of the killing s equations ( [ keq ] ) is called a killing vector field . in every subsection we will discuss killing symmetries of each coordinate system . an intriguing observation about the ds@xmath29 is embedding of the ds@xmath29 into flat @xmath42-dimensional spacetime , which was made by e. schrdinger ( 1956 ) . in @xmath42-dimensional minkowski spacetime , the einstein equation is trivially satisfied @xmath43 where capital indices , @xmath44 , represent @xmath42-dimensional minkowski indices run from @xmath16 to @xmath45 . if we set @xmath46 which implies a positive constant curvature of the embedded space , then the @xmath45-dimensional einstein equation ( [ 4 ] ) of ds@xmath29 is reproduced . a well - known coordinate system to cover entire @xmath45-dimensional hyperboloid is obtained from the following observation : as shown in fig . [ dsrfig1 ] , the relation between @xmath67 and the spatial length of @xmath68 is hyperbolic and spatial sections of a constant @xmath69 defines a @xmath70-dimensional sphere of radius @xmath71 . therefore , a convenient choice satisfying eq . ( [ 12 ] ) is @xmath72 where @xmath73 and @xmath74s@xmath75 for the spatial sections of constant @xmath76 satisfy @xmath77 subsequently , we have @xmath17 angle variables @xmath78 , such as @xmath79 inserting eq . ( [ gc ] ) and eq . ( [ omega ] ) into the metric ( [ 11 ] ) , we have a resultant metric rewritten in terms of the above coordinates @xmath80 : @xmath81 where @xmath82 is @xmath70-dimensional solid angle @xmath83 note that singularities in the metric ( [ dome ] ) at @xmath84 and @xmath85 are simply trivial coordinate artifacts that occur with polar coordinates . in these coordinates with a fixed time @xmath76 , the spatial hypersurface corresponds to a @xmath70-dimensional sphere of radius @xmath86 . thus , its radius is infinitely large at @xmath87 , decreases to the minimum radius @xmath50 at @xmath88 , and then increases to infinite size as @xmath89 . we again emphasize that the spatial section is compact ( finite ) except for the farthest past and future . in this coordinate system , @xmath90 is the only killing vector because the metric ( [ gcs ] ) is isometric under the rotation of a coordinate @xmath91 . on the other hand , @xmath92 is not a killing vector and missing of this killing symmetry breaks the conservation of energy so that hamiltonian is not defined properly and the quantization procedure does not proceed smoothly . however , @xmath93-matrix of the quantum field theory , if it exists , is known to be unitary because the coordinates cover globally the whole spacetime . an opposite direction is to assume an appropriate form of metric with an unknown function @xmath94 , @xmath95 and then to try to solve the einstein equations . curvature scalar of the metric ( [ gcm ] ) is computed as @xmath96 where the overdot denotes derivative of the rescaled time variable @xmath97 in this subsection . with the aid of eq . ( [ len ] ) , the einstein equation ( [ 4 ] ) becomes @xmath98 a particular solution of eq . ( [ gneq ] ) , irrespective of @xmath45 , can be obtained by solving two equations @xmath99 the solution of eq . ( [ triv ] ) is @xmath100 $ ] except unwanted trivial solution ( @xmath101 ) . since we can choose @xmath102 without loss of generality , via a time translation , @xmath103 , we have @xmath104 which is equivalent to the metric ( [ gcs ] ) found by a coordinate transformation . the general solution of eq . ( [ gneq ] ) should satisfy the following equations @xmath105 where @xmath106 is an arbitrary function of @xmath107 . according to the search by use of mathematica and a handbook @xcite , it seems that no other solution than eq . ( [ solg ] ) is known , yet . a noteworthy property of the ds@xmath9 is provided by computation of the weyl ( or conformal ) tensor @xmath109 for @xmath110 , or the cotton tensor @xmath111 for @xmath112 . ) is derived from the gravitational chern - simon action : @xmath113 since this gravitational chern - simon action is composed of cubic derivative terms so that it is dimensionless without any dimensionful constant . it means that 3-dimensional conformal gravity is described by this chern - simon term . ] substituting the einstein equation ( [ 4 ] ) and eq . ( [ 9 ] ) into the conformal tensors in eqs . ( [ 5 ] ) and ( [ 6 ] ) , we easily notice that they vanish so that ds@xmath9 is proven to be conformally flat : @xmath114 ( g_{\mu\rho } g_{\rho\nu } - g_{\mu\sigma } g_{\rho\nu } ) r = 0,\\ c^{\mu\nu } & = & -\frac{1}{4}\frac{\epsilon^{\mu\nu\rho}}{\sqrt { -g } } \nabla_{\rho } ( r - 4 \lambda ) \stackrel{r\sim\lambda}{=}0.\end{aligned}\ ] ] therefore , the condition ( [ 9 ] ) that the riemann curvature tensor is determined by the scalar curvature alone is equivalent to the condition of vanishing conformal tensor in this system . consequently the unique scale of the ds@xmath29 , @xmath115 , can be scaled away by a weyl ( scale ) transformation . the above conformal property of the ds@xmath29 suggests that conformal coordinate system is a good coordinate system . it is written in terms of conformal time @xmath116 as @xmath117 if we compare the metric of the global coordinates ( [ gcs ] ) with that of the conformal coordinates ( [ cmet ] ) , then coordinate transformation between two is summarized in a first - order differential equation of @xmath118 @xmath119 where @xmath120 provides a boundary condition such as @xmath121 . the unique solution of eq . ( [ foe ] ) is @xmath122 substituting the result ( [ usol ] ) into the metric ( [ cmet ] ) , we have @xmath123 since the metric ( [ cc ] ) is isometric under the rotation of @xmath91 , @xmath124 is a killing vector but there is no other killing vector . thus , the only symmetry is axial symmetry . note that there is one - to - one correspondence between the global coordinates ( [ gcs ] ) and the conformal coordinates ( [ cc ] ) , which means that the conformal coordinate system describes also entire de sitter spacetime . in addition , any null geodesic with respect to the conformal metric ( [ cc ] ) is also null in the conformally - transformed metric : @xmath125 therefore , penrose diagram for the ds@xmath29 can easily be identified from this metric ( [ cct ] ) , which contains the whole information about the causal structure of the ds@xmath29 but distances are highly distorted . however , we will discuss the penrose diagram for the ds@xmath29 in section [ pendi ] after the kruskal coordinate system is introduced . as mentioned previously , topology of the de sitter spacetime is cylindrical @xmath126 so the process to make the penrose diagram is to change the hyperboloid into a @xmath45-dimensional cylinder of a finite height , being @xmath127 @xmath128)$ ] . again note that the conformal coordinate system ( [ cc ] ) does not include the timelike killing symmetry so that the hamiltonian as a conserved quantity can not be chosen and the quantum theory on these coordinates is also sick . existence of conformal symmetry also affects much on the choice of field theoretic vacuum in the de sitter spacetime . from now on let us obtain the conformal metric ( [ usol ] ) by solving the einstein equations ( [ 2 ] ) under eq . ( [ cmet ] ) . if we compute the curvature scalar , we have @xmath129 here overdot denotes @xmath130 , and the same overdot in every subsection will also be used as derivative of the rescaled time variable in each corresponding subsection . then the einstein equation ( [ 4 ] ) becomes @xmath131 a particular solution of eq . ( [ einc ] ) , irrespective of @xmath45 , should satisfy the following equations @xmath132 the unique solution of eq . ( [ cneq ] ) with @xmath121 is proven to be the same as eq . ( [ usol ] ) . the general solution should satisfy the following equations @xmath133 where @xmath134 is an arbitrary function of @xmath135 . according to the search by use of mathematica and a handbook @xcite , no other solution than eq . ( [ usol ] ) is found yet . a noticed character of the pure ds@xmath29 from eq . ( [ 9 ] ) is the fact that it is maximally symmetric . suppose a comoving observer in the pure ds@xmath29 , then he or she may find maximally - symmetric spatial hypersurface orthogonal to his or her time direction . the corresponding planar ( inflationary ) metric takes the form @xmath137 where @xmath138 is cosmic scale factor and @xmath70-dimensional spatial metric @xmath139 of hypersurface should also carry maximal symmetries as a defining property : @xmath140 where @xmath141 . note that every nonvanishing component of the @xmath45-dimensional riemann curvature @xmath142 is expressed by the @xmath70-dimensional metric ( [ plme ] ) such as @xmath143 where the overdot denotes derivative of the rescaled time variable , @xmath144 . so does those of the ricci tensor @xmath145\gamma_{ij}\ ; , \end{aligned}\ ] ] and that of the scalar curvature @xmath146 in the de sitter spacetime of our interest , we only have a positive vacuum energy ( or equivalently a positive cosmological constant ) as the matter source given in eq . ( [ sour ] ) . let us interpret it in terms of a cosmological perfect fluid of which energy - momentum tensor can be written @xmath147 where @xmath148 and @xmath149 are the energy density and pressure respectively as measured in the rest frame , and @xmath150 is the velocity of the fluid . since the fluid is at rest for a comoving observer , the velocity of the fluid @xmath150 is @xmath151 and then @xmath152 . therefore , the equation of state @xmath153 tells it is a perfect fluid with a positive constant density and a negative constant pressure : @xmath154 obviously it is also consistent with conservation of the energy - momentum tensor ( [ sour ] ) , i.e. , @xmath155 . due to isotropy and homogeneity , spatial part of the metric ( [ plme ] ) @xmath139 is rewritten by well - known robertson - walker metric in terms of @xmath70-dimensional spherical coordinates @xmath156 , @xmath157 : @xmath158,\ ] ] where @xmath159 can have 0 ( flat ) or @xmath160 ( open ) or @xmath161 ( closed ) . under the metric ( [ plms ] ) , the einstein equations ( [ 2 ] ) are summarized by two friedmann equations : @xmath162-\frac{k}{a^2 } = \frac{d-2}{2(d-1)}\lambda-\frac{k}{a^{2 } } , \label{frid1}\\ \frac{\ddot{a}}{a } & = & - 4\pi g \left ( \frac{\rho}{d-1 } + p\right ) = \frac{d-2}{2(d-1)}\lambda . \label{frid2}\end{aligned}\ ] ] the right - hand side of eq . ( [ frid2 ] ) is always positive in the ds@xmath29 of a positive cosmological constant . thus , the universe depicted by the ds@xmath29 is accelerating or equivalently deceleration parameter @xmath163 is observed to be negative . when @xmath164 or @xmath160 , the right - hand side of eq . ( [ frid1 ] ) is always positive . it means that , once the universe started expanding , it is eternally expanding . or equivalently , once hubble parameter @xmath165 was observed to be positive , the rate of expansion of the universe always remains to be positive . even for @xmath166 case , once the cosmic scale factor @xmath138 arrives at critical size @xmath167 such as @xmath168 , and then the universe continues eternal expansion . the exact solutions of the friedmann equations ( [ frid1])([frid2 ] ) are nothing but inflationary solutions consistent with the above arguments @xmath169 if we interpret singularity at @xmath170 as the big bang of the creation of the universe , then open universe of @xmath171 experienced it at @xmath172 and an expanding flat universe of @xmath164 did it at past infinity @xmath173 while closed universe of @xmath166 did not . the constraint of the hyperboloid ( [ 12 ] ) embedded in @xmath42-dimensional minkowski spacetime can be decomposed into two constraints by introducing an additional parameter @xmath174 , of which one is a 2-dimensional hyperbola of radius @xmath175 @xmath176 and the other is a @xmath70-dimensional sphere of radius @xmath177 @xmath178 where @xmath179 denotes the sum over the index @xmath180 . therefore , a nice coordinate system to implement the above two constraints ( [ rrad])([llet ] ) is @xmath181 where range of @xmath182 is @xmath183 and that of @xmath184 is @xmath185 . since @xmath186 , our planar coordinates ( [ scct ] ) cover only upper - half the ds@xmath29 as shown in fig . [ dsrfig2 ] . lower - half the ds@xmath29 can be described by changing the @xmath42-th coordinate @xmath51 to @xmath187 . inserting these transformations ( [ scct ] ) into the flat @xmath42-dimensional minkowski metric ( [ 11 ] ) , we obtain a familiar form of the planar metric of the ds@xmath9 : @xmath188 which coincides exactly with the flat solution ( [ plso ] ) found by solving the einstein equations ( [ frid1])([frid2 ] ) . since the metric ( [ plm ] ) is not isometric under time translation , @xmath189 is not a timelike killing vector . this nonexistence implies no notion of conserved energy and hamiltonian , which hinders description of quantum gravity in the planar coordinates . however , the metric ( [ plm ] ) is independent of @xmath182 , so it satisfies form - invariance ( [ fin ] ) . therefore , @xmath190 s are spacelike killing vectors and the spatial geometry involves translational symmetries and rotational symmetries . the constraint of the hyperboloid ( [ 12 ] ) embedded in @xmath42-dimensional minkowski spacetime is again decomposed into two constraints by introducing an additional parameter @xmath192 , of which one is a 2-dimensional hyperbola of radius @xmath193 @xmath194 and the other is a @xmath70-dimensional sphere of radius @xmath195 @xmath196 therefore , a nice coordinate system to implement the above two constraints ( [ radii])([let ] ) is @xmath197 where @xmath198 s were given in eq . ( [ omega ] ) and @xmath199 will be identified with radial coordinate of static coordinate system . since @xmath200 and @xmath201 , the region of @xmath202 covers only a quarter of the whole ds@xmath29 as shown by the shaded region in fig . [ dsrfig3 ] . later , @xmath203 will be identified by a horizon of the pure de sitter spacetime . inserting these transformations ( [ sct ] ) into the @xmath42-dimensional minkowski metric ( [ 11 ] ) , we obtain a familiar form of static metric of the ds@xmath9 : @xmath204 dt^{2 } + \frac{dr^2}{\left [ 1 - \left ( \frac{r}{l}\right)^2 \right ] } + r^2 d \omega^2 _ { d-2},\ ] ] where @xmath205 the metric ( [ pcs ] ) is form - invariant ( [ fin ] ) for both time translation and rotation of the coordinate @xmath206 so that we have two killing vectors , @xmath207 and @xmath208 . correspondingly , spacetime geometry has axial and time translational symmetries . therefore , hamiltonian is well - defined in the static coordinates ( [ pcs ] ) but unitarity is threatened by existence of the horizon at @xmath203 . in order to describe the system with rotational symmetry in @xmath45-dimensions , a static observer may introduce the static coordinate system where the metric involves two independent functions of the radial coordinate @xmath192 , e.g. , @xmath209 and @xmath210 : @xmath211 curvature scalar of the metric ( [ pc ] ) is computed as @xmath212 -\left[\frac{d^2a}{dr^2}+2a\frac{d^2\omega}{dr^2}+2a\left(\frac{d\omega}{dr}\right)^2 + 3\frac{da}{dr}\frac{d\omega}{dr}\right].\ ] ] from eqs . ( [ sust ] ) and ( [ swst ] ) , simplified form of the einstein equations ( [ 2 ] ) is @xmath213 @xmath214 = \frac{(d-1)(d-2)}{l^2 } .\ ] ] schwarzschild - de sitter solution of eqs . ( [ dneq ] ) and ( [ eneq ] ) is @xmath215 here an integration constant @xmath216 can always be absorbed by a scale transformation of the time variable @xmath217 , @xmath218 , and the other integration constant @xmath219 is chosen to be zero for the pure de sitter spacetime of our interest , which is proportional to the mass of a schwarzschild - de sitter black hole @xcite . then the resultant metric coincides exactly with that of eq . ( [ pcs ] ) . structure of a fixed curved spacetime is usually probed by classical motions of a test particle . the shortest curve , the geodesic , connecting two points in the de sitter space is determined by a minimum of its arc - length @xmath220 for given initial point @xmath221 and end - point @xmath222 , and is parametrized by an arbitrary parameter @xmath223 such as @xmath224 : @xmath225 according to the variational principle , the geodesic must obey second - order euler - lagrange equation @xmath226 when the parameter @xmath223 is chosen by the arc - length @xmath220 itself , a force - free test particle moves on a geodesic . in this section , we analyze precisely possible geodesics in the four coordinate systems of the de sitter spacetime , obtained in the previous section . we also introduce several useful quantities in each coordinate system and explain some characters of the obtained geodesics . lagrangian for the geodesic motions ( [ arc ] ) is read from the metric ( [ gcs ] ) in the global coordinates : @xmath227 where @xmath223 is an affine parameter . corresponding geodesic equations ( [ geq ] ) are given by @xmath45-coupled equations @xmath228 @xmath229 since @xmath91 is cyclic , @xmath230 in eq . ( [ geq2 ] ) is replaced by a constant of motion @xmath231 such as @xmath232 let us recall a well - known fact that any geodesic connecting arbitrary two points on a @xmath70-dimensional sphere should be located on its greatest circle . due to rotational symmetry on the @xmath233 , one can always orient the coordinate system so that the radial projection of the orbit coincides with the equator , @xmath234 of the spherical coordinates . this can also be confirmed by an explicit check that eq . ( [ fixa ] ) should be a solution of eq . ( [ geq2 ] ) . it means that a test particle has at start and continues to have zero momenta in the @xmath235-directions ( @xmath236 ) . therefore , the system of our interest reduces from @xmath45-dimensions to ( @xmath237)-dimensions without loss of generality . insertion of eq . ( [ fixa ] ) into eq . ( [ am ] ) gives @xmath238 so that the remaining equation ( [ gteq1 ] ) becomes @xmath239 integration of eq . ( [ taud ] ) arrives at the conservation of energy @xmath240 @xmath241 where the effective potential @xmath242 is given by @xmath243 and thereby another constant of motion @xmath240 should be bounded below , i.e. , @xmath244 . eliminating the affine parameter @xmath223 in both eq . ( [ fixb ] ) and eq . ( [ ener ] ) , we obtain the orbit equation which is integrated as an algebraic equation : @xmath245 since the spatial sections are sphere @xmath233 of a constant positive curvature and cauchy surfaces , their geodesic normals of @xmath246 are lines which monotonically contract to a minimum spatial separation and then re - expand to infinity ( see dotted line in fig . [ geo1 ] ) . another representative geodesic motion of @xmath247 ( dashed line ) is also sketched in fig . for example , suppose that the affine parameter @xmath223 is identified with the coordinate time @xmath76 . then , we easily confirm from the above analysis that every geodesic emanating from any point can be extended to infinite values of the affine parameters in both directions , @xmath248 , so that the de sitter spacetime is said to be geodesically complete . however , there exist spatially - separated points which can not be joined by one geodesic . similar to the procedure in the previous subsection , we read automatically lagrangian for geodesics ( [ arc ] ) from the conformal metric ( [ cc ] ) : @xmath249,\ ] ] and then corresponding geodesic equations ( [ geq ] ) are @xmath250 @xmath251 since @xmath91 is cyclic , @xmath230 is replaced by a constant of motion @xmath231 such as @xmath252 since the @xmath70-angular coordinates @xmath253 constitute a ( @xmath17)-dimensional sphere , the same argument around eq . ( [ fixa ] ) is applied and thereby the system of our interest reduces again from @xmath45-dimensions to @xmath254-dimensions without loss of generality . substituting of eq . ( [ fixa ] ) into eq . ( [ am2 ] ) , we have @xmath255 and rewrite eq . ( [ coge1 ] ) as @xmath256 eq . ( [ taud2 ] ) is integrated out and we obtain another conserved quantity @xmath240 : @xmath257 in eq . ( [ ener2 ] ) we rescaled the affine parameter @xmath223 in order to absorb a redundant constant . combining eq . ( [ fixb2 ] ) and eq . ( [ ener2 ] ) , we obtain an orbit equation expressed by elliptic functions : @xmath258 \;,\ ] ] where @xmath259 @xmath260 ( @xmath261 ) represents a cylinder of finite height as shown in fig . geodesic of zero energy , @xmath262 , ( or equivalently zero angular momentum , @xmath246 ) , is shown as a dotted line , and that of positive energy , @xmath263 , ( or nonvanishing angular momentum , @xmath264 ) , as a dashed line in fig . [ gd11 ] . lagrangian for the geodesic motion ( [ arc ] ) for the flat space of @xmath164 is read from the metric ( [ plms ] ) : @xmath265 and the corresponding geodesic equations ( [ geq ] ) are @xmath266 @xmath267 @xmath268 since @xmath206 is cyclic , @xmath269 is replaced by a constant of motion @xmath231 such as @xmath270 if we use a well - known fact that any geodesic connecting arbitrary two points on a @xmath271-dimensional sphere should be located on its greatest circle , one may choose without loss of generality @xmath272 which should be a solution of eq . ( [ plge3 ] ) due to rotational symmetry on the @xmath271-dimensional sphere @xmath273 . therefore , the system of our interest reduces from @xmath45-dimensions to @xmath274-dimensions without loss of generality . + insertion of eq . ( [ fixa3 ] ) into eq . ( [ am3 ] ) gives @xmath275 so that the equations ( [ plge1])([plge2 ] ) become @xmath276 @xmath277 eliminating the third term in both eqs . ( [ taud3])([taudd3 ] ) by subtraction , we have the combined equation @xmath278 where @xmath279 is constant . finally , for @xmath280 , the radial equation ( [ ener3 ] ) is solved as @xmath281 for @xmath246 , eq . ( [ taudd3 ] ) becomes @xmath282 it reduces @xmath283 and @xmath284 is constant . information on the scale factor @xmath285 is largely gained through the observation of shifts in wavelength of light emitted by distant sources . it is conventionally gauged in terms of redshift parameter @xmath286 between two events , defined as the fractional change in wavelength : @xmath287 where @xmath288 is the wavelength observed by us here after long journey and @xmath289 is that emitted by a distant source . for convenience , we place ourselves at the origin @xmath290 of coordinates since our de sitter space is homogeneous and isotropic , and consider a photon traveling to us along the radial direction with fixed @xmath291 s . suppose that a light is emitted from the source at time @xmath292 and arrives at us at time @xmath293 . then , from the metric ( [ plms ] ) , the null geodesic connecting ( @xmath294 ) and ( @xmath295 ) relates coordinate time and distance as follows @xmath296 if next wave crest leaves @xmath297 at time @xmath298 and reach us at time @xmath299 , the time independence of @xmath300 provides @xmath301 for sufficiently short time @xmath302 ( or @xmath303 ) the scale factor @xmath285 is approximated by a constant over the integration time in eq . ( [ tim ] ) , and , with the help of @xmath304 ( or @xmath305 ) , eq . ( [ tim ] ) results in @xmath306 where @xmath307 from eq . ( [ hub ] ) and @xmath308 from eq ( [ depa ] ) . substituting eq . ( [ fac ] ) into eq . ( [ red ] ) , we have @xmath309 on the other hand , the comoving distance @xmath310 is not measurable so that we can define the luminosity distance @xmath311 : @xmath312 where @xmath313 is absolute luminosity of the source and @xmath314 is flux measured by the observer . it is motivated from the fact that the measured flux @xmath314 is simply equal to luminosity times one over the area around a source at distance @xmath45 in flat space . in expanding universe , the flux will be diluted by the redshift of the light by a factor @xmath315 and the difference between emitting time and measured time . when comoving distance between the observer and the light source is @xmath310 , a physical distance @xmath45 becomes @xmath316 , where @xmath317 is scale factor when the light is observed . therefore , we have @xmath318 inserting eq . ( [ fl ] ) into eq . ( [ ldis ] ) , we obtain @xmath319 using the expansion ( [ h0 ] ) , eq . ( [ zz ] ) is expressed by @xmath320 for small @xmath321 , eq . ( [ za ] ) can be inverted to @xmath322.\ ] ] when @xmath164 , the right - hand side of eq . ( [ nur ] ) yields @xmath323 and expansion of the left - hand side for small @xmath321 gives @xmath324 \nonumber\\ & = & \frac{1}{a_0h_0}\left[z-\frac{1}{2}(1+q_0)z^2+\cdots\right],\label{rz}\end{aligned}\ ] ] where @xmath325 was used in the second line and eq . ( [ zb ] ) was inserted in the third line . replacing @xmath310 in eq . ( [ dl ] ) by eq . ( [ rz ] ) , we finally have hubble s law : @xmath326\ ] ] which relates the distance to a source with its observed red shift . note that we can determine present hubble parameter @xmath327 and present deceleration parameter @xmath328 by measurement of the luminosity distances and redshifts . as a reference , observed value of @xmath327 at present is @xmath329 ( @xmath330 ) so that corresponding time scale @xmath331 is about one billion year and length scale @xmath332 is about several thousand @xmath333 . since the scale factor is given by an exponential function , @xmath334 , for the flat spacetime of @xmath164 , the left - hand side of eq . ( [ nur ] ) is integrated in a closed form : @xmath335 in addition , the redshift parameter @xmath286 is expressed as @xmath336 so the luminosity distance @xmath311 in eq . ( [ dl ] ) becomes @xmath337 comparing eq . ( [ dl2 ] ) with the hubble s law ( [ hl ] ) , we finally confirm that the expanding flat space solution of @xmath164 has present hubble parameter @xmath338 and the de sitter universe is accelerating with present deceleration parameter @xmath339 as expected . geodesic motions parametrized by proper time @xmath220 are described by the following lagrangian read from the static metric ( [ pcs ] ) : @xmath340\left(\frac{dt}{d\sigma}\right)^2 + \frac{1}{1-\left(\frac{r}{l}\right)^2 } \left ( \frac{dr}{d\sigma}\right)^2 + r^2 \sum_{b=1}^{d-2}\left ( \prod _ { a=1}^{b-1 } \sin ^2 \theta _ { a}\right ) \left ( \frac{d\theta_b}{d\sigma}\right)^2.\ ] ] since the time @xmath217 and angle @xmath206 coordinates are cyclic , the conjugate momenta @xmath240 and @xmath231 are conserved : @xmath341 @xmath342\frac{dt}{d\sigma}\;.\ ] ] by the same argument in the subsection [ pigo ] , the system of our interest reduces from @xmath45-dimensions to ( @xmath343)-dimensions without loss of generality , and then eq . ( [ am4 ] ) becomes @xmath344 from here on let us use rescaled variables @xmath345 , @xmath346 , and @xmath347 . note that @xmath348 can not exceed @xmath349 due to the limitation of light velocity . then second - order radial geodesic equation from the lagrangian ( [ sclag ] ) becomes @xmath350 integration of eq . ( [ taud4 ] ) leads to conservation of the energy @xmath351 @xmath352 where the effective potential @xmath242 is given by @xmath353 as shown in fig . [ geo4 ] , the motion of a particle having the energy @xmath354 can never lower than @xmath355 due to repulsive centrifugal force , which becomes @xmath16 as @xmath348 approaches @xmath16 . the ranges except @xmath356 are forbidden by the fact that kinetic energy should be positive . for @xmath357 indicated in fig . [ geo4 ] , a test particle moves bounded orbit within two turning points @xmath358 and @xmath359 . the perihelion @xmath358 and the aphelion @xmath359 were obtained from @xmath360 @xmath361 if the energy @xmath351 have minimum value of the effective potential @xmath362 , then the motion is possible only at @xmath363 , so that the orbital motion should be circular . shaded region in fig . [ geo4 ] is the allowable region for static observer , which is bounded by de sitter horizon ( @xmath364 ) . it corresponds to one fourth of the global hyperbolic region in fig . [ pen1 ] . solving for @xmath365 from eq . ( [ ener4 ] ) , we have @xmath366 then the integration of both sides gives @xmath367 where @xmath279 is an integration constant . if we choose the perihelion @xmath358 given in eq . ( [ semi ] ) for @xmath368 , @xmath279 is fixed by @xmath369 and then the aphelion @xmath359 is given at @xmath370 . when the energy @xmath351 takes maximum value @xmath371 , position of the aphelion at @xmath364 is nothing but the de sitter horizon . so the elapsed proper time for the motion from the perihelion to the aphelion , ( @xmath372 ) , is finite . changing the proper time @xmath220 in eq . ( [ geint ] ) to coordinate time of a static observer @xmath184 by means of eq . ( [ como4 ] ) , we find @xmath373 and the integration for @xmath357 gives @xmath374=\frac{4e-(j^2 - 1 + 2e)(1-x^2)}{\sqrt{-2e}(x^2 - 1 ) \sqrt{2e+(1-x^2)(1-j^2/x^2)}}.\ ] ] note that the ranges are @xmath375 in the case of @xmath376 , the integration of eq . ( [ getime ] ) gives @xmath377 to reach the de sitter horizon at @xmath364 , the energy @xmath351 should have a value @xmath354 irrespective of the value of @xmath348 as shown in fig . [ radig ] . for @xmath378 , @xmath379 is fixed by @xmath380 . when a test particle approaches the de sitter horizon , the elapsed coordinate time diverges as @xmath381 by combining eq . ( [ fixb4 ] ) with eq . ( [ geint ] ) and its integration , we obtain an elliptic orbit equation for @xmath357 : @xmath382[(1-j)^2 + 2e ] } } .\ ] ] if we choose @xmath379 as the perihelion at @xmath383 , @xmath384 becomes @xmath369 . from eq . ( [ semi ] ) , the semimajor axis @xmath385 of @xmath386 is given by @xmath387 eccentricity @xmath37 of the ellipse can be written @xmath388 dependence of the orbit for @xmath37 is the followings : @xmath389 this scheme agrees with qualitative discussion by using the effective potential ( [ efpo ] ) and the energy diagram in fig . [ geo4 ] . in terms of @xmath390 and @xmath37 , eq . ( [ oesol ] ) is rewritten by @xmath391 eq . ( [ gesan ] ) follows @xmath392 at @xmath383 and @xmath393 at @xmath394 as expected from eq . ( [ semi ] ) . as shown in fig . [ orbit ] , eq . ( [ gesan ] ) satisfies the condition for closed orbits so - called bertrand s theorem , which means a particle retraces its own foot step . let us begin with a spacetime with physical metric @xmath33 , and introduce another so - called unphysical metric @xmath395 , which is conformally related to @xmath33 such as @xmath396 here , the conformal factor @xmath397 is suitably chosen to bring in the points at infinity to a finite position so that the whole spacetime is shrunk into a finite region called penrose diagram . a noteworthy property is that the null geodesics of two conformally related metrics coincide , which determine the light cones and , in turn , define causal structure . if such process called conformal compactification is accomplished , all the information on the causal structure of the de sitter spacetime is easily visualized through this penrose diagram although distances are highly distorted . in this section , we study detailed casual structure in various coordinates in terms of the penrose diagram . since every penrose diagram is drawn as a two - dimensional square in the flat plane , each point in the diagram denotes actually a @xmath271-dimensional sphere @xmath273 except that on left or right side of the diagram . let us introduce a coordinate transformation from the static coordinates ( [ pcs ] ) to eddington - finkelstein coordinates @xmath398 such as @xmath399 where the range of @xmath400 is @xmath401 . as expected , @xmath402 results in a timelike curve for a static object at the origin , @xmath403 . then the metric in eq . ( [ pcs ] ) becomes @xmath404 though the possible domain of real @xmath195 corresponds to the interior region of the de sitter horizon [ 0,1 ) due to the logarithm of eq . ( [ stoe ] ) , the metric itself ( [ efc ] ) remains to be real for the whole range of @xmath195 since @xmath405 , { \rm tanh } [ ( x^+-x^-)/2l])$ ] has ( 1,0 ) at @xmath402 , ( 0,1 ) at @xmath406 , and @xmath407 at @xmath408 , so it covers the entire @xmath45-dimensional de sitter spacetime as expected . in order to arrive at penrose diagram of our interest , these coordinates are transformed into kruskal coordinates ( @xmath409 , @xmath410 ) by @xmath411 and then the metric takes the form @xmath412 .\ ] ] the value of @xmath413 has @xmath160 at the origin ( @xmath402 ) , @xmath16 at the horizon ( @xmath406 ) , and @xmath349 at infinity ( @xmath414 ) by a relation @xmath415 . in addition , another relation @xmath416 tells us that the line of @xmath417 corresponds to past infinity ( @xmath418 ) and @xmath419 does to future infinity ( @xmath420 ) . therefore , the entire region of the de sitter spacetime is drawn by a penrose diagram which is a square bounded by @xmath421 . at the horizon , @xmath203 so that @xmath415 implies @xmath422 . therefore , as shown in the fig . [ pen1 ] , the coordinate axes @xmath417 and @xmath419 ( dashed lines ) are nothing but the horizons and the arrows on those dashed lines stand for the directions of increasing @xmath409 and @xmath410 . the shaded region is the causally - connected region for the observer at the origin on the right - hand side of the square ( @xmath423 , @xmath402 ) . in the kruskal coordinates ( [ etok ] ) , a killing vector @xmath424 in the static coordinates is expressed as @xmath425 thus norm of the killing vector is @xmath426 note that the norm of the killing vector becomes null at @xmath422 . in the region of @xmath427 , the norm is spacelike , while a half of the region with negative @xmath410 is forbidden . timelike killing vector is defined only in the shaded region with @xmath428 as shown in fig . such existence of the killing vector field @xmath429 guarantees conserved hamiltonian which allows quantum mechanical description of time evolution . however , @xmath429 is spacelike in both top and bottom triangles and points toward the past in right triangle bounded by the southern pole in fig . [ pen1 ] . therefore , time evolution can not be defined beyond the shaded region . the absence of global definition of timelike killing vector in the whole de sitter spacetime may predict difficulties in quantum theory , e.g. , unitarity . as mentioned previously , the conformal metric ( [ cct ] ) describes entire de sitter spacetime and is flat except for a conformal factor @xmath430 because of the scale symmetry ( [ 8 ] ) . these properties are beneficial for drawing the penrose diagram . by comparing the conformal metric ( [ cct ] ) directly with that of the kruskal coordinates ( [ kc ] ) , we obtain a set of coordinate transformation @xmath431,\\ v&=&\tan\left[\frac{1}{2}\left(\frac{t}{l}-\theta_{1}+\frac{\pi}{2 } \right)\right],\end{aligned}\ ] ] where integration constants are chosen by considering easy comparison with the quantities in the static coordinates . since the range of conformal time @xmath116 is @xmath432 , the horizontal slice @xmath233 at @xmath433 ( @xmath434 ) forms a past ( future ) null infinity @xmath435 ( @xmath436 ) with @xmath437 as shown in fig . [ pen3 ] . when @xmath438 @xmath439 , it is a vertical line on the left ( right ) side with @xmath423 , which is called by north ( south ) pole . when @xmath440 @xmath441 , @xmath417 @xmath442 corresponding to a null geodesic ( or another null geodesic ) starts at the south ( or north ) pole at the past null infinity @xmath443 and ends at the north ( or south ) pole at the future null infinity @xmath444 , where all null geodesics originate and terminate ( see two dashed lines at @xmath445 degree angles in fig . [ pen3 ] ) . obviously , timelike surfaces are more vertical compared to the null geodesic lines and spacelike surfaces are more horizontal compared to those . therefore , every horizontal slice of a constant @xmath116 is a surface @xmath233 and every vertical line of constant @xmath446s is timelike ( see the horizontal and vertical lines in fig . [ pen3 ] ) . although this diagram contains the entire de sitter spacetime , any observer can not observe the whole spacetime . the de sitter spacetime has particle horizon because past null infinity is spacelike , i.e. , an observer at the north pole can not see anything beyond his past null cone from the south pole at any time as shown by the region @xmath447 in fig . [ pen4]-(a ) , because the geodesics of particles are timelike . the de sitter spacetime has future event horizon because future null infinity is also spacelike : the observer can never send a message to any region beyond @xmath448 as shown in fig . [ pen4]-(b ) . this fact is contrasted to the following from minkowski spacetime where a timelike observer will eventually receive all history of the universe in the past light cone . therefore , the fully accessible region to an observer at the north pole is the common region of both @xmath447 and @xmath448 , which coincides exactly with the causally - connected region for the static observer at the origin in fig . [ pen1 ] . by comparing the planar coordinates ( [ plm ] ) with the kruskal coordinates ( [ kc ] ) , we again find a set of coordinate transformation @xmath449 here we easily observe @xmath450 from eq . ( [ vv ] ) . @xmath413 has @xmath160 at both the origin @xmath451 and infinity @xmath452 by a relation @xmath453 . in fig . [ pen2 ] , the origin corresponds to the boundary line at left side but the infinity to the point at upper - right corner . according to another relation @xmath454 , past infinity @xmath455 has @xmath419 so it corresponds to the diagonal line , and future infinity @xmath456 has @xmath457 so it corresponds to the horizontal line at upper side of the penrose diagram . therefore , the planar coordinates cover only the half of the de sitter spacetime ( see the shaded region in fig . [ pen2 ] ) . every dashed line in fig . [ pen2 ] is a constant - time slice , which intersects with a line of @xmath451 and is ( @xmath17)=dimensional surface of infinite area with the flat metric of @xmath164 . although the whole de sitter spacetime is geodesically complete as we discussed in the subsection [ glogeo ] , half of the de sitter spacetime described by the planar coordinates is incomplete in the past as shown manifestly in fig . in this review , we have discussed classical geometry of @xmath45-dimensional de sitter spacetime in detail : sections include introduction of four representative coordinates ( global ( or closed ) , conformal , planar ( or inflationary ) , static ) , identification of killing vectors , geodesic motions , cosmological implication , and penrose diagrams . two important subjects are missing : one is group theoretic approach of the de sitter spacetime and the other is energy because we do believe they have to be systematically dealt with quantum theoretic topics like supersymmetry and hamiltonian formulation of quantum theory . once we try to supersymmetrize de sitter group , inconsistency is easily encountered , that either a supergroup including both unitary representations and isometries of the de sitter spacetime is absent or any action compatible with de sitter local supersymmetry contains vector ghosts @xcite . in de sitter spacetime two definitions are known to define the mass of it : one is the abbott - deser mass given as the eigenvalue of zeroth component of virasoro generators and the other is the quasilocal mass obtained from brown - york stress tensor associated to a boundary of a spacetime @xcite . however , unitarity and conserved energy are not satisfied simultaneously in quantum theory in the de sitter spacetime , and structure of de sitter vacuum seems to ask more discussion @xcite . strikingly enough recent cosmological observations suggest the existence of extremely - small positive cosmological constant , however it just leads to a new form of terrible cosmological constant problem . in the present stage , it seems to force us to find its solution by understanding quantum gravity ( in de sitter spacetime ) . obviously the topics we reviewed form a basis for the following research subjects still in progress , e.g. , de sitter entropy and thermodynamics , ds / cft correspondence , trans - planckian cosmology , understanding of vacuum energy in the context of string theory , and etc , of which ultimate goal should be perfect understanding of the cosmological constant problem as consequence of constructed quantum gravity . for convenience , various formulas and quantities which have been used in the previous sections are summarized in the following four subsections . from the metric ( [ gcm ] ) of the global coordinates ( @xmath458 ) , nonvanishing components of covariant metric @xmath33 are @xmath459 and its inverse @xmath54 has @xmath460 jacobian factor @xmath461 of the metric ( [ yd1 ] ) becomes @xmath462 nonvanishing components of the connection @xmath56 are @xmath463 for completeness , we mention non - zero components of the riemann curvature tensor @xmath58 , which are consistent with eq . ( [ 9 ] ) : @xmath464 \prod_{j=1}^{i-1}\sin^2\theta_j \;,&\end{aligned}\ ] ] and the ricci tensor @xmath60 : @xmath465\right\ } \prod_{j=1}^{i-1}\sin^2\theta_j \;.\end{aligned}\ ] ] curvature scalar @xmath62 coincides with the formula in eq . ( [ csgo ] ) . from the metric ( [ cmet ] ) of the conformal coordinates ( @xmath466 ) , nonvanishing components of covariant metric @xmath33 are @xmath467 and its inverse @xmath54 has @xmath468 jacobian factor @xmath461 of the metric ( [ zd1 ] ) becomes @xmath469 nonvanishing components of the connection @xmath470 are @xmath471 non - zero components of the riemann curvature tensor @xmath58 consistent with eq . ( [ 9 ] ) are @xmath472 \;,\nonumber\\ r^{i}_{\ ; j i j } & = & \frac{1}{f^2}\left[f^2+\left(\frac{df}{dt}\right)^2 \right ] \prod_{j=1}^{i-1}\sin^2\theta_j \;,\end{aligned}\ ] ] and non - zero components of the ricci tensor @xmath60 are @xmath473 \ ; , \nonumber\\ r_{ii } & = & \frac{1}{l^2f^2 } \left [ f\left(\frac{d^2f}{dt^2}\right ) + ( d-3)\left(\frac{df}{dt}\right)^2+(d-2)f^2 \right ] \prod_{j=1}^{i-1}\sin^2\theta_j \;.\end{aligned}\ ] ] therefore , curvature scalar @xmath62 in the conformal coordinates coincides with the formula in eq . ( [ csco ] ) . y. kim would like to thank m. spradlin for helpful discussions . this work was the result of research activities ( astrophysical research center for the structure and evolution of the cosmos ( arcsec ) and the basic research program , r01 - 2000 - 000 - 00021 - 0 ) supported by korea science @xmath493 engineering foundation . a.g . riess _ et al _ , astron . j. * 116 * , 1009 ( 1998 ) , astro - ph/9805201 , _ observational evidence from supernovae for an accelerating universe and a cosmological constant _ ; + p.m. garnavich _ et al _ , astrophys . j. * 509 * , 74 ( 1998 ) , astro - ph/9806396 , _ supernova limits on the cosmic equation of state _ ; + s. perlmutter _ et al _ , astrophys . j. * 517 * , 565 ( 1999 ) , astro - ph/9812133 , _ measurements of omega and lambda from 42 high - redshift supernovae_. for a review , see s. weinberg , rev . phys . * 61 * , 1 ( 1989 ) , _ the cosmological constant problem_. for reviews , see e. witten , _ marina del rey 2000 , sources and detection of dark matter and dark energy in the universe _ , pp.27 - 36 , hep - ph/0002297 , _ the cosmological constant from the viewpoint of string theory _ carroll , living rev . rel . * 4 * , 1 ( 2001 ) , astro - ph/0004075 , _ the cosmological constant _ ; + s. weinberg , _ marina del rey 2000 , sources and detection of dark matter and dark energy in the universe _ , pp.18 - 26 , astro - ph/0005265 , _ the cosmological constant problem _ ; + p.j.e . peebles and b. ratra , to appear in rev . phys . , astro - ph/0207347 , _ the cosmological constant and dark energy _ ; + t. padmanabhan , to appear in phys . rep . , hep - th/0212290 , _ cosmological constant - the weight of the vacuum _ ; + and references therein . j. martin and r.h . brandenberger , phys . rev . d*63 * , 123501 ( 2001 ) , hep - th/0005209 , _ the trans - planckian problem of inflationary cosmology _ ; + r.h . brandenberger and j. martin , mod . a*16 * , 999 ( 2001 ) , astro - ph/0005432 , _ the robustness of inflation to changes in superplanck scale _ niemeyer , phys . rev . d*63 * , 123502 ( 2001 ) , astro - ph/0005533 , _ inflation with a planck scale frequency cutoff _ ; + for a review , see r.h . brandenberger , to appear in the proceedings of _ 2002 international symposium on cosmology and particle astrophysics _ , hep - th/0210186 , _ trans - planckian physics and inflationary cosmology_. n. kaloper , m. kleban , a. lawrence , s. shenker , and l. susskind , jhep * 0211 * , 037 ( 2002 ) , hep - th/0209231 , _ initial conditions for inflation _ danielsson , jhep * 0207 * , 040 ( 2002 ) , hep - th/0205227 , _ inflation , holography , and the choice of vacuum in de sitter space_. a. strominger , jhep * 0111 * , 034 ( 2002 ) , hep - th/0106113 , _ the ds / cft correspondence _ ; + for a review , see r. bousso , rev . phys . * 74 * , 825 ( 2002 ) , hep - th/0203101 , _ the holographic principle_. n.d . birrell and p.c.w . davies , _ quantum fields in curved space _ , chapter 5 , cambridge university press . e.w . kolb and m.s . turner , _ the early universe _ , chapters 8 @xmath493 11 , addison - wesley publishing company . s.w . hawking and g.f.r . ellis , section 5.2 of _ the large scale structure of space - time _ , cambridge university press ; + c.w . misner , k.s . thorne , and j.a . wheeler , _ gravitation _ , chapter 27 , w.h . freeman and company ; + s. weinberg , _ gravitation and cosmology _ , chapter 16 , john wiley @xmath493 sons . for lecture notes , see m. spradlin , a. strominger , and a. volovich , hep - th/0110007 , _ les houches lecture on de sitter space_. a.d . polyanin and v.f . zaitsev , _ handbook of exact solutions for ordinary differential equations _ , crc press . gibbons and s.w . hawking , phys . rev . d*15 * , 2738 ( 1977 ) , _ cosmological event horizons , thermodynamics , and particle creation_. k. pilch , p. van nieuwenhuizen , and m.f . sohnius , commun . * 98 * , 105 ( 1985 ) , _ de sitter superalgebras and supergravity _ ; + c.m . hull , jhep * 9807 * , 021 ( 1998 ) , hep - th/9806146 , _ timelike t - duality , de sitter space , large @xmath494 gauge theories and topological field theory_. l.f . abbott and s. deser , nucl . b*195 * , 76 ( 1982 ) , _ stability of gravity with a cosmological constant _ ; + j.d . brown and j.w . york , phys . rev . d*47 * , 1407 ( 1993 ) , gr - qc/9209012 , _ quasilocal energy and conserved charges derived from the gravitational action_. a. kaiser and a. chodos , phys . rev . d*53 * , 787 ( 1996 ) , _ symmetry breaking in the static coordinate system of de sitter space - time_.

classical geometry of de sitter spacetime is reviewed in arbitrary dimensions . topics include coordinate systems , geodesic motions , and penrose diagrams with detailed calculations . = 16.5 cm -1.85 cm -2 cm = .22 in hep - th/0212326 * classical geometry of de sitter spacetime : + an introductory review * + yoonbai kim@xmath0skku.ac.kr ] , chae young oh@xmath1newton.skku.ac.kr ] , and namil park@xmath1newton.skku.ac.kr ] + _ @xmath2bk21 physics research division and institute of basic science , sungkyunkwan university , + suwon 440 - 746 , korea + @xmath3school of physics , korea institute for advanced study , + 207 - 43 , cheongryangri - dong , dongdaemun - gu , seoul 130 - 012 , korea _

extrasolar planets are common ; over 300 systems have been discovered ( e.g. , exoplanet.eu ) . recent studies have targeted higher mass @xcite , lower mass @xcite , and younger objects @xcite . identifying young planets is important to define the time scale for planet formation and thus distinguish the possible formation process(es ) . young stars still surrounded by the circumstellar material which forms planets are typically located at distances of @xmath2100 pc and are thus inherently faint and often obscured . they also manifest strong magnetic activity ( e.g. , * ? ? ? * ) and are highly spotted . numerous , large spots complicate detection of extrasolar planets through radial velocity ( rv ) monitoring @xcite because a spot that is partially visible at all times on the surface of an inclined star mimics rv modulation ( e.g. , * ? ? ? * ; * ? ? ? @xcite studied 12@xmath3300 myr old nearby stars and found no evidence for planets with masses @xmath21@xmath32 m@xmath1 at the 3 @xmath4 level . @xcite identified a minimum mass 6.1 m@xmath1 planet in a 852 day period orbit around the 100 myr old g1@xmath3g1.5 v star hd 70573 . more recently , @xcite reported a @xmath010 m@xmath1 planet in a 3.56 day orbit around the 10 myr old star tw hya , although @xcite identify this result as attributable to spots . in this letter we present our observations of the young stars dn tau , v836 tau , and v827 tau . while the v827 tau visible light data clearly implicate spots as the cause of the apparent rv variability , corresponding data for dn tau and v836 tau suggest the presence of giant planets . our infrared ( ir ) observations show that spots cause the rv variations seen in all three stars . in 2 we describe the observations , in 3 present our data analysis and the evidence for spots , and in 4 provide a brief discussion . we summarize in 5 . visible light spectra of dn tau ( m0 ) , v836 tau ( k7 ) , and v827 tau ( k7 ) were taken at the mcdonald obervatory 2.7 meter harlan j. smith telescope , between november , 2004 and january , 2008 , with the coud echelle spectrograph @xcite . a 1.2@xmath5 slit yielded r@xmath060,000 . integration times were @xmath01800 s ; average seeing was @xmath02@xmath5 . thar exposures taken immediately before and after each spectrum provided wavelength calibration ; typical rms values for the dispersion solution precision were @xmath04 m s@xmath6 . rv standards @xcite were observed on every night of every run ; their overall rms scatter is 140 m s@xmath6 . we obtained 43 spectra of dn tau , 21 of v836 tau , and 20 of v827 tau and applied standard iraf reduction routines . details are given in @xcite and @xcite . we observed dn tau , v836 tau , v827 tau , and the rv standards hd 65277 ( k5 ) and gj 281 ( m0 ) on ut 2008 february 13@xmath320 with cshell @xcite , the high - resolution , ir spectrograph at the nasa irtf 3-m telescope . the seeing was 0.4@xmath30.8@xmath5 . each object was observed on 6@xmath38 nights . the 0.5@xmath5 slit yielded r@xmath046,000 . we obtained data in 10@xmath5 nodded pairs . spectra were centered at 2.298 @xmath7 m ( vacuum ) . integration times were @xmath01 hour for the t tauri stars and @xmath08 minutes for the standards . the signal to noise ratio ( snr ) was @xmath070@xmath3120 . data were reduced as described in @xcite . relative rvs were determined by cross correlating a high snr , fiducial spectrum against all other spectra for the same target . we used six orders spanning @xmath05700 to 6800 . uncertainties were estimated from the standard deviation of the mean for the 6 orders , added in quadrature with the 140 m s@xmath6 uncertainty derived from the rv standards ( 2 ; * ? ? ? * ) . rvs were corrected for the earth s barycentric motion . optimum periods and uncertainties for phasing the rv data were selected based on power spectra @xcite . for dn tau we found p@xmath86.33 @xmath90.20 days and a false alarm probability ( fap ) of @xmath100.001 , for v836 tau , p@xmath82.48 @xmath90.49 days and fap@xmath80.10 , and for v827 tau , p@xmath83.76 @xmath90.06 days and fap@xmath110.001 . we also checked for periodicity using the discrete fourier transform plus clean method of roberts et al . the strongest power spectrum peaks for dn tau and v836 tau occur at the same periods . the clean method recovered a best period of 3.61 d for v827 tau , within @xmath02 @xmath4 of the above estimate . the phased rv data are shown in figures 1@xmath33 . the presence of a starspot will distort the line profile at the rv that corresponds to the stellar velocity at the location of the spot . this distortion is in proportion to the ratio of quiescent photosphere surface brightness and surface brightness within the spot , at the observing wavelength , and the fraction of stellar surface covered by the spot ( e.g. , * ? ? ? thus , asymmetries in the line profiles originating from spots will be present for all lines in the spectrum of a young star and are typically correlated with the rv measured from the same spectrum . these asymmetries have become the standard criterion for rejecting starspots as the cause of false rv signals ( e.g. , * ? ? ? * ; * ? ? ? * ; * ? ? ? * ) . for each of the six orders used to determine the rvs , we cross - correlated all absorption lines and measured the cross - correlation function ( ccf ) for that order . the average of these six ccfs was used to measure the bisector spans ( lower panels of figures 1@xmath33 ) . the linear correlation coefficient and associated fap @xcite is listed in the captions . as expected for a spotted star , a clear correlation between bisector span and rv is observed for v827 tau . dn tau and v836 tau show no correlation , suggesting that the variability is not the result of spots . the contrast between a 4000 k photosphere and a 3000 k spot @xcite is greater in visible than in ir light because flux scales as a steeper function of temperature at wavelengths shorter than the black body peak ( e.g. , * ? ? ? given the decreased spot to photosphere contrast in the near - ir , the amplitude of the rv modulation will be smaller . conversely , if a planet drives the rv modulation , the amplitude should be the same in visible and ir light . @xcite used near - ir observations to search for companions to low - mass objects , exploiting telluric absorption lines for high - precision rv measurements . figure 4 shows an example of a gj 281 k - band spectrum and illustrates our similar approach . we created models by combining high resolution telluric absorption @xcite and cool stellar spectra ( the sunspot atlas of wallace & livingston 1992 ) , applying a range of velocity shifts relative to the telluric lines . other free parameters are @xmath12sin@xmath13 , a gaussian fwhm for the spectrometer line spread function , scale factors for line depths , and a first order continuum normalization function . we employed the marquardt method for non - linear least squares fitting @xcite of each model to an observed spectrum . the difference between the stellar and telluric velocities in the best fit model spectrum yields the rv , which was then corrected for barycentric motion . figures 1@xmath33 show the ir - derived relative rvs . the data are phased to the periods given in 3.1 . the rv standard deviation in the ir data for hd 65277 is 127 m s@xmath6 and for gj 281 is 98 m s@xmath6 . internal errors , measured from the least squares fitting , are @xmath040 m s@xmath6 for both standards . for the young stars , internal errors were 100@xmath3300 m s@xmath6 , depending on the snr achieved . random errors , which we assume add in quadrature with our internal errors to give the overall scatter in velocities , are 120 m s@xmath6 for hd 65277 and 90 m s@xmath6 for gj 281 . we use 110 m s@xmath6 as our final value for the random errors . the uncertainties shown for the ir data in figures 1@xmath33 represent the sum , in quadrature , of the individual internal error and the 110 m s@xmath6 random error . within our measurement precision , we are unable to detect any ir rv variability in dn tau and v836 tau . v827 tau shows significant ir rv variations but at a reduced amplitude from those observed in visible light . figures 1 and 2 show the visible light rv modulation for dn tau and v836 tau , with full amplitudes of @xmath14 and @xmath15 m s@xmath6 , respectively . within the 1 @xmath4 uncertainties , all but one point in the ir rvs of dn tau are consistent with zero ; all six ir rvs of v836 tau also show no variation . these results indicate that no planets are present around dn tau or v836 tau with masses greater than a few m@xmath1 at @xmath110.5 au or @xmath010 m@xmath1 at @xmath01 au , despite the absence of a correlation between the visible light rvs and bisector spans . @xcite identify v836 tau and v827 tau as rv variables with peak - to - peak amplitudes of 7@xmath38 km s@xmath6 . apparently the density and size of spots on v836 tau vary ; historical data may serve as an additional criterion for heavily spotted young stars . the primary conclusion from our visible light data is that the lack of a correlation between the line bisector span and the rv is not proof of a reflex motion companion . in addition , the rv period can change significantly with new data . initial analysis of 20 visible light rvs for dn tau , taken over 2.5 years , indicated convincing modulation with p@xmath87.5 days and fap@xmath80.002 . although not markedly different from rotation period estimates of 6.0@xmath36.4 days @xcite , @xmath16 for p@xmath87.5 days was more favorable than that for a secondary peak at 6.3 days . removing the fit to either the 7.5 or 6.3 day period from the rv data and recalculating the power spectrum yielded no significant peak , suggesting that the data were best represented with only one period . with the addition of rvs measured in winter 2007@xmath32008 , the integrity of the 7.5 day period was diminished and the 6.3 day period came to dominate the power spectrum . the rotation period of v836 tau has been stable for decades at 6.76 days @xcite . we find a different rv period , 2.48 days , and substantially reduced power in the rv modulation near 6.76 days . the rv period for v827 tau , 3.76 days , is indistinguishable from previously determined values of the rotation period @xcite . if the visible light rv modulation originates in spots , why do nt the bisector spans correlate ( figures 1 and 2 ) ? figure 3 clearly shows correlation for v827 tau ; many other stars show a correlation as well ( e.g. , * ? ? ? * ; * ? ? ? * ; * ? ? ? we do not believe that this can be attributed to a stronger impact of spots on particular spectral lines because the same echelle orders were used to determine the bisector spans for all targets . @xcite show that when @xmath12sin@xmath13 is smaller than the spectrometer resolution , rv and bisector variations originating in spots can mimic the behavior expected from short period giant planets . the @xmath12sin@xmath13 of dn tau and v836 tau , @xmath010 km s@xmath6 , are not much larger than our visible light spectral resolution , 5 km s@xmath6 , while v827 tau and lkca 19 ( huerta et al . 2008 ) have @xmath12sin@xmath13 values of @xmath020 km s@xmath6 , suggesting qualitative agreement with the simulations of @xcite . we have measured the rvs of the @xmath02 myr old t tauri stars dn tau , v836 tau , and v827 tau in visible and ir light ; the variations we see in all three systems are likely the result of starspots . furthermore : ( 1 ) periodogram analysis can reveal the presence of a period but not necessarily a reliable value until rv measurements densely sample the full phase of the periodic signal . ( 2 ) the lack of correlation of line bisector spans with rvs for some stars with spots is an important problem to address in the search for planets around young stars . ( 3 ) high - resolution , ir spectroscopy is critical for the verification of young planet candidates ; without the contrast in rv modulation amplitude between the visible light and ir data , it is unclear whether spots or a companion cause variability . ( 4 ) in the case of the spotted young star , v827 tau ( figure 3 ) , we observe a substantial reduction in rv amplitude between the visible light and ir data . this result can be exploited to improve our understanding of starspot temperature and filling factors . ( 5 ) t tauri stars are virtually guaranteed to have spots at some level ; if planets are also present , their detection will likely require disentanglement of the blended rv signals and will benefit greatly from measurements that span a broad range in wavelength . the authors acknowledge the sim young planets key project ( pi c. beichman ) for research support ; funding was also provided by nasa grant 05-sso05 - 86 . we thank g. blake , c. salyk , and e. schaller for sharing keck time ( our first attempt at ir observations of dn tau ) , d. gies and a. fullerton for their assistance implementing the clean power spectrum estimate , and the referee , j. eisloeffel , for a prompt and helpful report . lp thanks p. bodenheimer and t. barman for informative discussions . this work made use of the simbad database , the nasa astrophysics data system , and the two micron all sky survey , a joint project of the univ . of massachusetts and ipac / caltech , funded by nasa and the nsf . we recognize the significant cultural role that mauna kea plays in the indigenous hawaiian community and are grateful for the opportunity to observe there .

in searches for low - mass companions to late - type stars , correlation between radial velocity variations and line bisector slope changes indicates contamination by large starspots . two young stars demonstrate that this test is not sufficient to rule out starspots as a cause of radial velocity variations . as part of our survey for substellar companions to t tauri stars , we identified the @xmath02 myr old planet host candidates dn tau and v836 tau . in both cases , visible light radial velocity modulation appears periodic and is uncorrelated with line bisector span variations , suggesting close companions of several m@xmath1 in these systems . however , high - resolution , infrared spectroscopy shows that starspots cause the radial velocity variations . we also report unambiguous results for v827 tau , identified as a spotted star on the basis of both visible light and infrared spectroscopy . our results suggest that infrared follow up observations are critical for determining the source of radial velocity modulation in young , spotted stars .

Now open for just under three months, Walter and Margarita Manzke's hallmark restaurant, Republique, is coming under fire for its 3% healthcare surcharge added to every bill. KPCC reports that a few vocal Yelpers have complained of the surcharge that was instituted as a response to the requirement for companies with more than 50 full-time employees to provide healthcare. Everyone at Republique is entitled to sign up for an H.M.O., even down to the dishwashers, who are offered full-time status. One Yelper writes regarding the surcharge: "Needless to say... I didn't really feel that great about the mandatory 3% healthcare charge tacked on to the bill. I'd rather have used that money to go get a massage after sitting on those stools for so long." Another complains: "One interesting side note is the 3% surcharge on the check that apparently serves to provide healthcare for the employees. Something about this strikes me as tacky. Sure, I could take this 3% out of my 20% tip, but why put me in that position to begin with? A bit silly for such an otherwise upscale experience." And finally, a more reasonable response: "Lastly, they add a 3% surcharge to the bill for employee health insurance. I'm cool with that, but they should make it easy to not tip on the 3%. They warn you to do the math, but give me a break. Subtract 3% and then add 20%? Just feels like they expect you to say 'screw it' and tip on the entire total." The practice has been common in the City of San Francisco, where restaurants collect an additional fee to apply to their employees' healthcare costs. However, a study by the Office of Labor Standards found that only a third of the fees collected, which amounted to $14 Million in 2011, actually went toward healthcare. It's that major discrepancy that's caused problems for the reputation of the healthcare surcharge. But that's in San Francisco. Republique is hoping to make a statement not only offering the benefit, but guaranteeing that the 3% charge will allay medical costs, just like the 28-day aged cote de boeuf is indeed, aged for 28 days. Staff at the restaurant have said that only a handful of customers have openly griped about the charge, but hefty percentage of Yelp reviews have mentioned the fee. Should restaurants charge an extra nominal fee to help provide healthcare for their employees, or should they simply implement those costs across the rest of the bill? ·Health care surcharge riles customers at top LA eatery [KPCC] ·All Republique Coverage [~ELA~] ||||| Today’s exciting new development in the anti-Obamacare resistance is that Gator’s Dockside, a Florida restaurant chain, is warning its customers of the terrible things that are happening to it, and them, as a result of the new health-care law. “The costs associated with ACA compliance could ultimately close our doors,” instructs the sign, “Instead of raising prices on our products to generate the additional revenue needed to cover the costs of ACA compliance, certain Gator’s Dockside locations have implemented a 1% surcharge on all food and beverage purchases only.” A one-percent surcharge! It’s like an Ayn Rand novel come to life! Conservatives find this development very exciting. Obviously, the restaurateur is thinking about this from the perspective of an angry talk-radio-listening Republican rather than that of a hard-headed capitalist. There are costs associated with all kinds of government regulations and spending, but he’s not creating a line item on his tab to highlight his share of, say, financing the Department of Defense. The main problem here is that, as an act of propaganda, this is completely self-defeating. Customers are told that the dreaded Obummercare may “ultimately” put the restaurant out of business – maybe one day, when the Sharia FEMA camp portion is phased in. But in the meantime, they’re covering it by making the two people buying lunch fork over an additional 20 cents to cover health insurance for the restaurant’s employees. That really doesn’t sound like the worst deal in the world. ||||| A Florida group that that manages several restaurants is already banking money for when the Obamacare employer mandate takes effect in 2015, and is charging customers a 1 percent surcharge on food and drinks. Currently only management employees of the eight Gator’s Dockside restaurants receive health insurance, but starting in December, in order to comply with the employer mandate, about 250 full-time employees will also receive health insurance, according to CNN Money. Sandra Clark, director of operations for the Gator Group that manages the restaurants, “is not sure how much the company is spending on compliance, but estimates that it will cost $500,000 a year to extend insurance to its full-time hourly restaurant workers,” CNN Money reported. “The surcharge may bring in about $160,000 a year, she hopes.” Gator’s Dockside isn’t the first restaurant to start charging an Obamacare fee. A Los Angeles restaurant has also implemented a surcharge. Gator’s Dockside could choose to not give full-time employees coverage even once the mandate kicks in, and pay a fine. Or the chain could reduce its current full-time employees’ hours, so that they only work part-time – and thus don’t qualify for health coverage under the employee mandate. But as the surcharge shows, Obamacare is no free lunch. Most businesses probably won’t opt to add a specific surcharge in order to cover their new health care costs, but some will certainly raise prices – or reduce quality of their products. Obamacare hasn’t driven down the costs of health insurance, or found a magical new source to cover those costs.

– An otherwise nondescript restaurant chain in Florida is suddenly national news thanks to a new policy: Gator's Dockside has added a 1% surcharge to cover the costs of the Affordable Care Act, reports CNN Money. Participating restaurants aren't trying to hide it, either. "The costs associated with ACA compliance could ultimately close our doors," reads a sign to patrons. "Instead of raising prices on our products to generate the additional revenue needed to cover the costs of ACA compliance, certain Gator's Dockside locations have implemented a 1% surcharge on all food and beverage purchases only." An executive with the chain estimates that it will cost $500,000 a year to provide all its workers with insurance when the employer mandate kicks in next year, and she figures the surcharge will bring in about $160,000 annually. Dumb move: "Obviously, the restaurateur is thinking about this from the perspective of an angry talk-radio-listening Republican rather than that of a hard-headed capitalist," writes Jonathan Chait at the Daily Intelligencer. "There are costs associated with all kinds of government regulations and spending, but he’s not creating a line item on his tab to highlight his share of, say, financing the Department of Defense." Smart move: "As the surcharge shows, Obamacare is no free lunch," writes Katrina Trinko at the Heritage Foundation. "Most businesses probably won’t opt to add a specific surcharge in order to cover their new health care costs, but some will certainly raise prices—or reduce quality of their products. Obamacare hasn’t driven down the costs of health insurance, or found a magical new source to cover those costs." Similar move: Eater notes that a popular Los Angeles restaurant, Republique, asks diners to pay a 3% surcharge for employee health care costs. The restaurant makes it optional, however, and says it is not specifically tied to the new law's mandates.

A child actor famous for his role in a "Star Wars" prequel was arrested last week after leading South Carolina police on a 25-mile high-speed chase, Colleton County Sheriff's Sgt. Kyle Strickland told NBC News on Sunday. Strickland identified the actor as Jake Broadbent, 26, formerly known as Jake Lloyd, who played Anakin Skywalker in "Star Wars: Episode I — The Phantom Menace." According to his IMDB profile, Broadbent's last film was in 2005. Strickland said the chase began after the sheriff's office was alerted to a reckless driver about 2 p.m. ET. The driver was Broadbent, and when a deputy followed him, he speeded away. "He starts passing cars on the double yellow line," Strickland said. "He's going head on into oncoming traffic." Deputies followed Broadbent onto Interstate 95, where he was driving "upwards of 100 miles per hour," Strickland said. Broadbent drove through a grassy median, where he crashed through an old fence, then onto a frontage road, Strickland said. At a dead end, when the pavement became a logging road overgrown with trees, Broadbent kept driving, Strickland said. "He bounced off a bunch of them like a pinball machine," he said. Strickland said it was unclear why Broadbent was in South Carolina — his address is in Colorado — or why he tried to evade police. "He didn't appear to be on drugs or intoxicated," Strickland said. Broadbent remained in the Colleton County Detention Center, where he was being held Sunday in lieu of $10,700 bond on charges of resisting arrest, reckless driving, driving without a license and failure to stop. ||||| FILE- In this May 13, 1999, file photo, actor Jake Lloyd; who portrays young Anakin Skywalker in the film "Star Wars Episode I: The Phantom Menace;" plays a game during the Electronic Entertainment Expo... (Associated Press) FILE- In this May 13, 1999, file photo, actor Jake Lloyd; who portrays young Anakin Skywalker in the film "Star Wars Episode I: The Phantom Menace;" plays a game during the Electronic Entertainment Expo... (Associated Press) WALTERBORO, S.C. (AP) — A former child actor who starred in one of the "Star Wars" movie sequels faces charges after leading South Carolina deputies on a high-speed chase. Colleton County Sheriff's deputies on Wednesday arrested a 26-year-old man they confirmed through a former talent agent was Jake Lloyd, who played a young Anakin Skywalker in the 1999 movie "Star Wars: Episode I - The Phantom Menace," Sgt. Kyle Strickland said Sunday. The man gave his name as Jake Broadbent, Strickland said. The man's birthdate matched the actors' listed by movie database IMDB.com and a hometown of Fort Collins, Colorado, where Lloyd was born. The man was charged with failing to stop for officers and reckless driving after hitting speeds over 100 miles an hour, Strickland said. Deputies in coastal Charleston County initially tried to stop the fleeing vehicle early Wednesday afternoon, but quit chasing after the man drove into neighboring Colleton County, Sheriff's Office Major Eric Watson said Sunday. The chase lasted for more than 25 miles before Lloyd drove off Interstate 95, plowed through a fence, and continued speeding along a parallel frontage road, authorities said. The road ended at a dead end, but the vehicle kept going into a wooded area before it hit several small trees and stopped. The man had not posted bond and remained in jail Sunday evening, Strickland said. Lloyd said in a 2012 interview that the role he performed when he was 10 years old made his youth hellish because he was bullied by other children. His last acting credit was in 2005, according to IMDB.com.

– A former Star Wars actor allegedly went to the dark side last week, taking South Carolina police officers on a high-speed chase for 25 miles. Jake Lloyd—best known for portraying a young Anakin Skywalker in 1999's Star Wars: Episode I - The Phantom Menace—was reported to police on Wednesday afternoon for driving recklessly in Colleton County, and allegedly took off when deputies pursued him onto I-95. "He starts passing cars on the double yellow line," Sgt. Kyle Strickland tells NBC News. "He's going head on into oncoming traffic." The 26-year-old reportedly hit speeds of 100 miles per hour and crashed through a fence. When he reached a wooded area, Lloyd used the force, so to speak, and was not deterred by the trees. "He bounced off a bunch of them like a pinball machine," Strickland says. Lloyd eventually stopped, however, and gave police the surname "Broadbent." A former agent confirmed that the man was in fact Lloyd, according to an AP report. Strickland noted the former child actor "didn't appear to be on drugs or intoxicated" at the time of arrest but gave no insight into why he may have decided to run from the law. Lloyd was booked for driving without a license, reckless driving, failing to stop for officers, and resisting arrest, and was still in jail as of last night. His last film was the 2005 drama Madison, according to IMDb.

the disease can cause three different categories of symptoms and signs with possible overlap in the affected patients [ 2 , 3 ] . these patients may complain of the neck ( pain , stiffness , and limited range of motion ) or suffer from radiculopathy or even myelopathy . neurologic symptoms are usually aroused when the space available for the neural elements is reduced by osteophytes , hypertrophied ligamentum flavum , or a herniated disc . in those patients whose main manifestation of the disease is neck complains , conservative treatment is usually recommended , while in some with cervical spondylotic radiculopathy ( csr ) or myelopathy ( csm ) , surgery may be associated with better satisfactory outcomes [ 57 ] . although , some authors still have doubts about the long - term results of surgery in these cases [ 2 , 8 ] . the poor prognostic factors usually quoted in the surgical treatment of the patients include older age , abnormal cervical curvature , multisegmental compression , more duration of symptoms , higher number of comorbidities , decreased signal intensity on t1-weighted images , increased signal intensity on t2-weighted images , and existence of cord atrophy in preoperative magnetic resonance images ( mris ) [ 1 , 5 , 6 , 911 ] . although many papers have been published about the surgical outcome of the patients with csm or csr , according to our knowledge , very few studies have been conducted to compare the two . in this retrospective study , we aim to compare functional outcome of surgery in patients with csr and csm . 910106 ) , we retrospectively reviewed our patients with csm and csr who had been operated from august 2006 to january 2011 . those patients with predominant manifestation of csr were placed in group a , while the others were placed in group b. in rare cases , who complained of both conditions with equal intensity , due to the differences in the clinical significance , we conventionally put them in the second group . our inclusion criteria included refractory complains to aggressive medical treatment more than six weeks , significant neurologic deficit ( especially if progressive ) , and a followup period more than 24 months . we excluded those patients with secondary spondylosis ( due to previous trauma , congenital anomalies , and infectious or inflammatory diseases ) , significant underlying disease ( uncontrolled diabetes mellitus , severe osteoporosis , etc . ) , tandem stenosis ( significant accompanying spinal stenosis in another area of the spine ) , and those who had history of previous surgery . preoperatively , in group b , the presence of increased signal intensity inside the cord on t2-weighted mri was assessed by two self - governing radiologists and was described as positive when they both were in concurrence . we did not grade this increased intensity and only classified it as normal or positive . in this study , surgical techniques and approaches were not considered as the effective variables , and we primarily aimed to efficiently decompress the neural elements and stabilize the spine if necessary . in our opinion , it matters little that this goal would be achieved with anterior or posterior approach , spondylodesis or disc arthroplasty , anterior cervical discectomy or corpectomy , and laminectomy or laminoplasty ; but each technique or approach should be used in its proper patient . after the informed consent form was signed , demographic and imaging data were recorded , and then the patient operated . all the procedures have been carried out by the fist author ( fok ) with a relative similar technique during this period of time . we used neck disability index ( ndi ) as an assessment tool to evaluate functional outcome . translation and validation study of the iranian version of this international questionnaire has been already performed by mousavi in 2007 and proved to be extremely reliable . the ndi questionnaire was completed preoperatively and then every six months after surgery . and patient satisfaction with surgery was also evaluated subjectively . at the last visit , the cases were asked to choose one of the following responses regarding their satisfaction with the surgical treatment , according to criteria adopted from the north american spine society low back outcome instrument : ( 1 ) surgery met my hopes , ( 2 ) i did not improve as much as i had hoped , but i would undergo the same surgery for the same outcome , ( 3 ) surgery helped , but i would not undergo the same treatment for the same outcome , or ( 4 ) i am the same as or worse than i was before the surgery . we used independent samples t - test for comparison and pearson and kendall 's tau - b correlation coefficients for measuring the dependency . statistical package for the social sciences ( spss ) software version 11.5 was used for statistical analysis . initially , 150 patients were eligible for inclusion , but later ten patients due to short duration of followup were excluded . all the surgical approaches in group a were carried out from anterior , while 19.5% of the procedures in group b were performed posteriorly . we operated no patient with combined anterior and posterior approach . in 52 ( 76.5% ) of the patients with radiculopathy ( group a ) , there was only one level of cervical involvement , and in the remaining 16 ( 23.5% ) , two levels of involvement were present . in contrary to group a , in myelopathy group , only 22 ( 30.6% ) of the patients had a monosegmental involvement , and two , three , four , and five levels of involvement were observed in 20 ( 27.8% ) , 16 ( 22.2% ) , 6 ( 8.3% ) , and 8 ( 11.1% ) , respectively . regarding to surgical delay ( the time interval between appearances of complains and surgery ) and its relation to functional recovery ( ndi ) , based on pearson 's correlation coefficient , in group a , the longer delay caused a worse surgical outcome ( ndi ) , while this relationship was not observed in group b. in addition , in group b , there were 30 cases ( 41.7% ) with increased signal intensity inside the cord preoperatively , and based on kendall 's tau - b correlation coefficient , there was no significant relationship between this imaging signal change and our surgical outcomes ( correlation coefficient of 0.12 , p = 0.204 for final ndi ) . functional status of the patients ( ndi ) before surgery and at last followup visit is shown in table 2 . patient 's satisfaction from the surgery was also assessed at the last followup and depicted in the same table . although in comparing csr with csm patients , satisfactory rates from the surgery seemed to be higher in the first group , this was not significant , statistically . overall , surgery could significantly improve ndi in both groups ( p < 0.001 ) . regarding to improved ndi and patient 's satisfaction score , , we had three implant failures ( all in group a ; screw loosening ) , and three pseudarthroses ( two case in group a and one in group b ) . five cases needed reoperation ( three due to symptomatic pseudarthrosis , one adjacent segment disease , and one symptomatic device loosening ) . one patient in group a had a transient paralysis of the recurrent laryngeal nerve , lasting for two months . three patients had superficial wound infection , all treated by local wound care and antibiotic therapy . we investigated 140 patients with refractory cervical spondylosis who had been treated with surgery . our study showed that the functional results of surgery and patients ' satisfaction rate in csr compared to csm are apparently better but statistically comparable . usually , it is said that csm compared to csr more commonly occurred in older patients [ 15 , 16 ] . in this study , we were unable to find a significant difference in the age distribution . the sex ratio of the patients reported in different studies is highly variable [ 6 , 11 , 1618 ] . the sex ratios of our patients in the two groups were markedly different from each other ; radiculopathy was more common in women , whereas the opposite is myelopathy . several surgical prognostic factors have been reported in the literature . in a prospective study , older age and greater number of underlying preoperative comorbidities are associated with lower surgical outcome . 65 patients with surgically treated csm found that good prognostic factors in these cases included younger age and lower preoperative baseline modified japanese orthopaedic association score , but the severity of cord compression , signal intensity change on magnetic resonance imaging scans , and treatment delay have little prognostic value . our research results also confirmed that signal change and treatment delay had no adverse effect on functional outcome of these patients . vice versa , chatley et al . , in 2009 , in a research on 64 cases with a 6-months followup period showed that the signal change indicative of a chronic constrictive lesion was a predictor of poor surgical results . naderi also found that age less than 60 , normal preoperative cervical lordosis , and normal signal intensity ( versus increased signal intensity on t2 mri ) within the spinal cord were associated with more favorable neurological postoperative improvements . as we noted , we did not consider the surgical techniques and approaches as the effective variables and assumed that for each patient , a proper decompressive surgery with or without spinal stabilization ( if indicated ) has been carried out . in a relatively large systematic review carried out by mummaneni et al . , they used evidence - based medicine to judge against different surgical decompressive techniques commonly used in csm patients . ultimately , the researchers concluded that these variable techniques had comparable outcome , and the surgical technique can not be an important factor in determining the proper results , although they noted that laminectomy seemed to have a delayed worsening rate . this rule also applies to the patients with csr , and decompression itself is still the main principle of treatment . in our study , only six cases in group b had laminectomy alone ( without associated posterior instrumented fusion ) and this small number could not have a great impact on the overall conclusions . in the study , we conducted that 88.2% of the csr patients and 77.8% of the csm patients had good or excellent results ( patient satisfaction score 1 or 2 ) , while 5.9% and 16.7% , respectively , showed postoperative deterioration ( score 4 ) . to compare the results evaluated 76 patients with csr who are treated by 1 or 2 level anterior cervical discectomy and fusion . he categorized then into group a ( iliac crest bone graft alone ) and group b ( iliac crest bone graft and plating ) . he reported 55% and 88.9% excellent or good results in groups a and b , respectively . the other study ( related to radulovi et al . ) has been carried out on 57 surgically treated patients with csm that showed good functional improvement irrelevant to the chosen surgical approach . in this study , 75% of the cases showed postoperative improvement , while 21% remained unchanged and 4% deteriorated . in comparison with these two studies , the major limitations of our study are our retrospective method of research and diversity in surgical techniques . obviously , a randomized control trial study will be able to offer stronger advices . in the future , it is suggested in order to decrease the confounding effect of the surgical type on the surgical outcome ; it is better to compare the two groups with one similar surgical technique and approach . for example , a comparison between the results of surgical treatment of csr and csm in the patients treated with anterior cervical discectomy and fusion . in conclusion , surgery was associated with an improvement in the neck disability index in the both groups ( p < 0.001 ) . regarding the improved ndi and patient 's satisfaction score , functional results in both groups were similar and comparable .

background . cervical spondylosis can cause three different categories of symptoms and signs with possible overlap in the affected patients . aim . we aim to compare functional outcome of surgery in the patients with cervical spondylotic radiculopathy and myelopathy , regardless of their surgical type and approach . materials and methods . we retrospectively reviewed 140 patients with cervical spondylotic radiculopathy and myelopathy who had been operated from august 2006 to january 2011 , as group a ( 68 cases ) and group b ( 72 cases ) , respectively . the mean age was 48.2 and 55.7 years , while the mean followup was 38.9 and 37.3 months , respectively . functional outcome of the patients was assessed by neck disability index ( ndi ) and patient satisfaction with surgery . results . only in group a , the longer delay caused a worse surgical outcome ( ndi ) . in addition , in group b , there was no significant relationship between imaging signal change of the spinal cord and our surgical outcomes . improvement in ndi and final satisfaction rate in both groups are comparable . conclusions . surgery was associated with an improvement in ndi in both groups ( p < 0.001 ) . the functional results in both groups were similar and comparable , regarding this index and patient 's satisfaction score .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Building Efficiently Act of 2016''. SEC. 2. EXPANSION OF NEW ENERGY EFFICIENT HOME CREDIT. (a) In General.--Paragraph (2) of section 45L(a) of the Internal Revenue Code of 1986 is amended by striking ``and'' at the end of subparagraph (A), by striking the period at the end of subparagraph (B) and inserting ``, and'', and by adding at the end the following: ``(C) in lieu of subparagraphs (A) and (B), in the case of qualified new energy efficient home that is a qualified energy efficient residential rental property, 3.3 percent of the cost of construction of such property, reduced by any expenditure not taken into account under this section by reason of subsection (f).''. (b) Qualified Energy Efficient Residential Rental Property Defined.--Subsection (b) of section 45L of such Code is amended by adding at the end the following: ``(5) Qualified energy efficient residential rental property.-- ``(A) In general.--The term `qualified energy efficient residential real property' means a building which is residential rental property which is described in subparagraph (B), (C), or (D). ``(B) New or reconstructed building.--A building is described in this subparagraph if-- ``(i) the certification requirements of subparagraph (E) with respect to the building are met, ``(ii) the original use of which commences with the taxpayer, and ``(iii) the building is placed in service after the date of the enactment of the Building Efficiently Act of 2016. ``(C) Improvements to existing building.--A building is described in this subparagraph if, only after improvements are made to the building-- ``(i) the certification requirements of subparagraph (E) with respect to the building are met, ``(ii) the original use of the improved building commences with the taxpayer, ``(iii) the improved building is placed in service after the date of the enactment of the Building Efficiently Act of 2016, and ``(iv) the taxpayer elects to the application of this paragraph with respect to the building. ``(D) Buildings acquired by purchase.--A building is described in this subparagraph if the building-- ``(i) is acquired by purchase from an unrelated person, ``(ii) meets the certification requirements of subparagraph (E), and ``(iii) is placed in service after the date of the enactment of the Building Efficiently Act of 2016. ``(E) Certification requirements.--The requirements of this subparagraph are met if, with respect to a building, the building is certified in accordance with subsection (d) as being constructed, reconstructed, or retrofitted, as the case may be, under a plan designed to reduce energy and power consumption of the building by 40 percent or more in comparison to-- ``(i) in the case of retrofits made to an existing building, the baseline annual energy and power consumption of the building, or ``(ii) in any other case, a reference building which meets the minimum requirements of the International Energy Conservation Code 2004 using methods of calculation under subsection (d). ``(F) Baseline annual energy and power consumption.--The baseline annual energy and power consumption of any building shall be determined by using-- ``(i) a building energy performance benchmarking tool designated for purposes of this paragraph by the Administrator of the Environmental Protection Agency, which is based upon energy and power consumption data during the 1-year period ending on the date on which retrofits under the plan are placed in service, or ``(ii) such other methods of calculation as certified by the Secretary in accordance with subsection (d). ``(G) Related persons.--For purposes of subparagraph (D), a person is related to another person if-- ``(i) the persons are members of an affiliated group (as defined in section 1504), or ``(ii) the persons have a relationship described in subsection (b) of section 267; except that, for purposes of this clause, the phrase `80 percent or more' shall be substituted for the phrase `more than 50 percent' each place it appears in such subsection and rules similar to the rules of subsections (c) and (e) (other than paragraphs (4) and (5) thereof) shall apply.''. (c) Conforming Amendment.--Section 45L(d) is amended by striking ``subsection (c)'' both places it appears and inserting ``subsection (b)(5) or (c)''. (d) Effective Date.--The amendments made by this section shall apply to property placed in service after December 31, 2015. SEC. 3. ELIMINATION OF BASIS REDUCTION FOR LOW-INCOME HOUSING PROPERTIES RECEIVING CERTAIN ENERGY BENEFITS. (a) New Energy Efficient Home Credit.--Subsection (e) of section 45L of the Internal Revenue Code of 1986 is amended-- (1) by striking ``Adjustment.--For purposes'' and inserting ``Adjustment.-- ``(1) In general.--For purposes'', and (2) by adding at the end the following new paragraph: ``(2) Exception for low-income housing properties.-- Paragraph (1) shall not apply to any property with respect to which a credit is allowed under section 42.''. (b) Energy Efficient Commercial Buildings Deduction.--Subsection (e) of section 179D of the Internal Revenue Code of 1986 is amended-- (1) by striking ``Reduction.--For purposes'' and inserting ``Reduction.-- ``(1) In general.--For purposes'', and (2) by adding at the end the following new paragraph: ``(2) Exception for low-income housing properties.-- Paragraph (1) shall not apply to any property with respect to which a credit is allowed under section 42.''. (c) Energy Credit.--Paragraph (3) of section 50(c) of the Internal Revenue Code of 1986 is amended-- (1) by striking ``and'' at the end of subparagraph (A), (2) by striking the period at the end of subparagraph (B) and inserting ``, and'', and (3) by adding at the end the following new subparagraph: ``(C) paragraph (1) shall not apply to any property with respect to which a credit is allowed under section 42.''. (d) Effective Date.--The amendments made by this section shall apply to property placed in service after December 31, 2015.

Building Efficiently Act of 2016 This bill amends the Internal Revenue Code to expand the new energy efficient home tax credit to allow, in lieu of the existing credit, a credit for 3.3% of the cost of constructing a new energy efficient home that is a qualified energy efficient residential rental property. An energy efficient residential rental property must be certified as being constructed, reconstructed, or retrofitted under a plan designed to reduce energy and power consumption of the building by at least 40% compared to: (1) the baseline annual energy and power consumption of the building in the case of a retrofit made to an existing building, or (2) a reference building which meets the minimum requirements of the International Energy Conservation Code 2004 in any other case. The bill also eliminates the basis reduction requirements for low-income housing properties receiving: (1) the new energy efficient home credit, (2) the energy efficient commercial buildings deduction, or (3) the credit for investments in energy property.

Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period. ||||| Steve Jobs Stuffed Toy Fans of Steve Jobs can now own a stuffed toy of the late tech visionary. Called the iCEO, the plush doll launched on Wednesday by pillow company Throwboy and looks remarkably like the Apple founder. Standing 15 inches tall, the toy Job comes with removable rimless glasses, his signature black turtle neck and 100% denim jeans. Throwboy is touting the Steve Jobs stuffed toy as a limited-edition collector's item, as only 1,200 have been made. The iCEO can be pre-ordered now for $60, with a limit of two for each person. The item will ship in August 2012 and you can order it from other countries. "I've wanted to design something like this for about 2 years," Roberto Hoyos told Mashable. "It really comes from a place of love and it's took a lot of hard work to get to a design that I was proud of. It was also my way to give back to someone that had a great impact on my life. 10% of the proceeds from each doll goes to the American Cancer Society." This isn't the first time a company has launched a toy that pays tribute to Jobs. Earlier this year, In Icons set up a promotional page to tout the launch of its 12-inch Steve Jobs action figure that looked eerily realistic. However, the company now has a message on its site that it has stopped selling the item due to pressure received from Apple lawyers and the Jobs family. "I would like to take this opportunity to reiterate that the original intention for creating the figurine was driven by a fan's admiration of Steve," the site said, noting that the company respects copyright/trademark rights and wasn't using Apple product models with the figure. "Unfortunately, we have received immense pressure from the lawyers of Apple and Steve Jobs family… and have decided to completely stop the offer, production and sale of the Steve Jobs figurine out of our heartfelt sensitivity to the feelings of the Jobs family." In Icons noted the company would issue refunds to anyone that pre-ordered the action figure for $99. Throwboy said it doesn't think the stuffed toy will run into problems with Apple. "I don't believe it will be an issue," Hoyos said. "I mean no disrespect, and I hope that they see it will bring a lot of joy to people." It's unclear at this point if Throwboy has informed Apple about its Steve Jobs stuffed toy model. The company has not yet responded to Mashable's inquiry about the matter. Will you pre-order the Steve Jobs stuffed toy? Is it too soon for companies to sell products related to Jobs? Let us know your thoughts in the comments. Images via Throwboy BONUS: Steve Jobs Action Figure

– Cuddle up with your favorite CEO: A 15-inch plush stuffed doll of the late Steve Jobs is now for sale. The "iCEO," released by pillow company Throwboy, will set you back $60. It features removable glasses, a black turtle neck, and real denim jeans, reports Mashable. The toy is limited-edition, with only 1,200 being made. No word yet on whether Apple will try to stop the doll, as it did with an action figure earlier this year.

there is growing evidence that occupational burnout has been widely present among nurses since the end of last century . a patient - oriented nursing model requires high - quality care while at the same time may increase mental and physical stress in nurses . a survey involving 711 hospitals showed that more than 40% of usa nurses were dissatisfied with their jobs , and the percentage of nurses who were planning to leave their jobs was more than 33% in england and scotland and more than 20% in the usa . chinese nurses may be facing even higher occupational stress than counterparts from other countries because of poor doctor - patient relationship and frequent violence against medical staff in hospitals . several studies have reported that more than 40% of nurses had emotional exhaustion or high - level burnout . the quality of the nursing practice environment was considered to be a main factor associated with nurse recruitment and retention . therefore , the practice environment scale has been widely used to quantitatively evaluate the job satisfaction of nurses . the chinese version of the practice environment scale ( cppe-38 ) was translated in 2009 , and one study that included 573 participants from different hospitals showed that the satisfaction scores were very low in china . gender , clinical work duration , geographic location of the work place , and highest nursing qualification were demonstrated to be predictive factors of low satisfaction . however , this study included hospitals of different levels , and nurse satisfaction scores from a tertiary hospital were not specifically identified . in our present study , the satisfaction scores were studied in a university - affiliated tertiary hospital in shanghai , china to investigate the associated factors and the change of satisfaction from 2013 to 2015 . this study is a historical control study based on a paper questionnaire survey performed in 2013 and 2015 . all nurses from huashan hospital , fudan university were asked to complete the cppe-38 anonymously at the end of 2013 and 2015 . the questionnaire was conducted in the same general population , although the population sizes in the two years were different as a small proportion of nurses may have resigned or moved to other hospitals over the two years of the study . linear regression analysis was performed based on the survey in 2013 to identify the potential factors correlated with each item and subscale of the cppe-38 . multiple improvement measures were then established to improve the satisfaction of nurses in 2014 and 2015 . the scores of cppe-38 in 2015 were compared with those in 2013 to evaluate the effects of these improvement measures . the study was approved by the human research ethics committee of huashan hospital , fudan university . the main components of the questionnaire were the 38 items of the cppe-38 , which were divided into 5 subscales , including internal work motivation ( 10 questions ) , control over practice ( 6 questions ) , interpersonal interaction ( 7 questions ) , supportive leadership and handling conflict ( 10 questions ) , internal relationship and autonomy ( 5 questions ) . other information in the questionnaire included gender , marital status , highest educational degree , age , years of being a nurse , years at the current hospital , years in the current unit , work unit , and job title . first , a web - based communication platform was established to receive any comments or complaints from the nurses . second , a psychological forum was offered twice a year to carry out psychological intervention in some special units based on the questionnaire and the problems exposed by the communication platforms . third , continuing education was enhanced among the nurses and a certificate was established to authenticate their capacities . all statistical analyses were performed by the spss 16.0 ( chicago , il , usa ) . the continuous data was expressed as mean sd and the enumeration data was expressed as number ( percentage ) . the potential associated factors with the scores of cppe-38 were screened using the backward method of linear regression analysis . the dependent factor was the subscale score , and the total score of the cppe-38 and the independent factors included all the demographic data . the cppe-38 scores in 2013 and 2015 were compared using the student s t - test . this study is a historical control study based on a paper questionnaire survey performed in 2013 and 2015 . all nurses from huashan hospital , fudan university were asked to complete the cppe-38 anonymously at the end of 2013 and 2015 . the questionnaire was conducted in the same general population , although the population sizes in the two years were different as a small proportion of nurses may have resigned or moved to other hospitals over the two years of the study . linear regression analysis was performed based on the survey in 2013 to identify the potential factors correlated with each item and subscale of the cppe-38 . multiple improvement measures were then established to improve the satisfaction of nurses in 2014 and 2015 . the scores of cppe-38 in 2015 were compared with those in 2013 to evaluate the effects of these improvement measures . the study was approved by the human research ethics committee of huashan hospital , fudan university . the main components of the questionnaire were the 38 items of the cppe-38 , which were divided into 5 subscales , including internal work motivation ( 10 questions ) , control over practice ( 6 questions ) , interpersonal interaction ( 7 questions ) , supportive leadership and handling conflict ( 10 questions ) , internal relationship and autonomy ( 5 questions ) . other information in the questionnaire included gender , marital status , highest educational degree , age , years of being a nurse , years at the current hospital , years in the current unit , work unit , and job title . first , a web - based communication platform was established to receive any comments or complaints from the nurses . second , a psychological forum was offered twice a year to carry out psychological intervention in some special units based on the questionnaire and the problems exposed by the communication platforms . third , continuing education was enhanced among the nurses and a certificate was established to authenticate their capacities . all statistical analyses were performed by the spss 16.0 ( chicago , il , usa ) . the continuous data was expressed as mean sd and the enumeration data was expressed as number ( percentage ) . the potential associated factors with the scores of cppe-38 were screened using the backward method of linear regression analysis . the dependent factor was the subscale score , and the total score of the cppe-38 and the independent factors included all the demographic data . the cppe-38 scores in 2013 and 2015 were compared using the student s t - test . a total of 1,050 respondents were recruited out of 1,198 nurses in 2013 , with a response rate of 87.6% . the cppe-38 scores of each item and the subscale scores , as well as total satisfaction in 2013 are listed in table 2 . the total satisfaction score was 2.990.64 . among the five subscales , the lowest score was 2.400.59 in interpersonal interaction and the highest score was 3.150.40 in internal work motivation . nurses from the operating room and post - anesthesia care unit had the lowest scores in internal work motivation and total satisfaction ( table 4 ) . nurses with an educational degree higher than a masters degree had the highest score for internal relationship and autonomy ( table 5 ) . the cppe-38 survey was performed again at the end 2015 , with a total of 1,085 respondents . the results showed significantly higher scores in the subscales of internal work motivation , control over practice , interpersonal interaction , and internal relationship and autonomy . but no significant difference was observed in the scores for supportive leadership , handling conflict , or the total satisfaction score ( table 6 ) . our present study identified several significant associated factors in the cppe-38 scores . with the introduction of improvement measures , including web - based communication platform , psychological forum , continuing education , psychological rewards , and income elevation , we observed increases in the scores for internal work motivation , control over practice , interpersonal interaction , and internal relationship and autonomy . a positive practice environment is critical to improving the quality of nursing care and reducing mortality according to the american nurses credentialing center . the practice environment scale is one of the most widely used scales in evaluating job satisfaction of nurses , and prior to 2010 had been reported by more than five countries and translated into three languages . however , the practice environment scale has seldom been reported in studies from mainland china . a cross - sectional study performed by cao et al . recruited 435 paper - based and 163 online - based questionnaires and reported a mean score ranging from 2.66 to 3.05 . the average score in our present study was 2.990.64 and only two subscales had scores lower than 3.0 , including control over practice and interpersonal interaction . organization has been reported as one of the factors associated with the scores and the respondents from a level - three hospital account for only 58.0% among all the participants in the cao et al . our multiple regression analysis found that nurses from the operating room , post - anesthesia care unit , and intensive care unit had the lowest satisfaction scores . the operating department has been considered a frequent source of adverse events and work stress . the intensive care unit is also a complicated unit with low job satisfaction among the nurses . a survey performed by lai et al . showed that 48.9% of nurses from the intensive care unit intended to leave their jobs . several issues has been proposed as important regarding the current status of chinese nurses , including nursing shortages , inadequate salary income , little support from managers , and less professional autonomy . therefore , we paid more attention to the psychological and living status of nurses from these special units by establishing a web - based communication platform and a psychological forum . dissatisfaction on income is common in chinese hospitals and the employment status has been reported to be a critical issue influencing the job satisfaction of nurses . in our study group , the income and benefits of a relatively small proportion of nurses were provided by the government or the university while most of the nurses were contract - based employees whose benefits might be less . thus we raised both the salary income and social benefits among the contract - based employees . finally , our improvement measures were proven to be effective according to the increase in scores of the cppe-38 survey two years later . inadequate education might lead to less confidence and professional autonomy in caring for patients during practice . support from the nurse managers and doctors might increase autonomy , thus we establish an online communication platform to receive any comments or complaints from the nurses who might be facing a difficult problem . davies et al . reported a statistically significant association between autonomy and educational preparation in qualified staff undertaking continuing education and having contact with educational centers . . showed that implementation of a phased educational approach could improve communications between healthcare staff and improve job satisfaction in a developing country . first , this was a single center study recruiting nurses from a university - affiliated tertiary hospital and the results may not be representative of all hospitals in china . a multi - center investigation should be performed to evaluate the effects of the improvement measures in improving the satisfaction status of nurses . second , we did not correlate the improvement of cppe-38 scores with the quality of care . further studies should be performed to evaluate the impact of the improvement measures on patient and hospital outcomes . working location and educational degree were two factors influencing the scores of the 38-item chinese version of practice environment scale . the improvement measures , including web - based communication platform , psychological forum , continuing education , psychological rewards , and income elevation , may improve the satisfaction of nurses . a multi - center study should be performed to evaluate the effects of these measures .

backgroundthe present study was performed to quantitatively examine nurse satisfaction , to investigate the associated factors influencing satisfaction , and to evaluate the effect of improvement measures based on these factors.material/methodsa survey using the 38-item chinese version of the practice environment scale ( cppe-38 ) was performed in a university - affiliated tertiary hospital in shanghai , china in 2013 . linear regression analysis was performed to screen for associated factors related to each cppe-3 score and the total satisfaction score . several improvement measures were established to improve nurse satisfaction , and the cppe-38 survey was again performed in 2015 to evaluate the effect of these improvement measures.resultsa total of 1,050 respondents were recruited in 2013 , with a response rate of 87.6% . the total satisfaction score of the cppe-38 was 2.990.64 . the lowest score in a subscale of the cppe-38 was 2.400.59 for interpersonal interaction and the highest score was 3.150.40 for internal work motivation . work location was associated with scores for work motivation and total satisfaction , while the highest education degree was associated with scores for internal relationship and autonomy . the scores for internal work motivation , control over practice , interpersonal interaction , and internal relationship and autonomy were significantly improved in 2015 after two years of improvement efforts , while the total satisfaction score was not significantly different compared to the 2013 score.conclusionsworking location and education degree were two factors correlated with cppe-38 scores in our hospital . humanistic concerns , continuing education , and pay raise may improve the practice satisfaction of nurses .

the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .

anisodamine , an antagonist of muscarinic receptor , has been used therapeutically to improve blood flow in circulatory disorders such as septic shock in china since 1965 . the main mechanism of anisodamine for anti - shock proposed in pharmacology for chinese medical students is to improve blood flow in the microcirculation . here , we suggest a new mechanism for its anti - shock effect . that is , anisodamine , by blocking muscarinic receptor , results in rerouting of acetylcholine to 7 nicotinic acetylcholine receptor ( 7nachr ) bringing about increased acetylcholine - mediated activation of 7nachr and the cholinergic anti - inflammatory pathway .