bluuebunny/crossref_metadata_2025 huggingface dataset:
Flash flood dynamics and composition in a semiarid mountain watershed
Authors: Desilets Sharon L. E. , Ferré Ty P. A. , Ekwurzel Brenda
Published: December 2008

Flash flood hydrographs were examined using water stable isotopes (deuterium and oxygen) and a plug‐flow lumped catchment model to assess the origin and routing processes of flood water in a semiarid basin in southwestern United States. Precipitation and stream water were sampled during storm and flood conditions at high and low elevations. Isotope mixing relationships readily determined the predominance of three sources for the representative summer monsoon events: high elevation precipitation from two major subbasins and base flow. Each flood progressed through a series of source water contributions, as indicated by several segments of linear mixing between these end‐members. We developed a plug‐flow lumped catchment model to test possible governing processes for specific watershed and forcing conditions. Results suggest two main findings: First, these flood events were generated primarily from event water runoff in high elevations that mixed at the flood bore with pre‐event base flow resident in the stream. The power, speed, and turbulence of the flood bore cause it to mix with, ride atop and push the resident in‐stream water in the front of the rising limb. Second, the timing and volume of flood waves from subbasins are identified by their combined isotopic signature at the basin outlet; this approach may provide an effective mesoscale constraint for rainfall‐runoff models.
Estimating Agricultural Nitrous Oxide Emissions
Authors: Del Grosso Stephen J. , Wirth Tom , Ogle Stephen M. , Parton William J.
Published: December 2008

Emissions of nitrous oxide (N2O), a potent greenhouse gas, tend to be underestimated by standard methods of quantifi cation provided by the Intergovernmental Panel on Climate Change (IPCC) [IPCC, 2006], recent research suggests. Better quantification of agricultural N2O emissions improves greenhouse gas inventories, allows for better evaluation of the environmental impacts of different cropping systems, and increases the understanding of the nitrogen (N) cycle in general. Proper quantifi cation of N2O emissions is particularly important in the context of calculating net greenhouse gas emissions from biofuel cropping systems because these emissions offset the greenhouse gas benefits of displacing fossil fuel and can even lead to biofuel systems being a net greenhouse gas source [Crutzen et al., 2008].

The global warming potential of N2O is approximately 300 times that of carbon dioxide, and N2O emissions represent approximately 6% of the global anthropogenic greenhouse gas source [IPCC, 2007]. N2O also contributes to stratospheric ozone destruction. N2O is produced in soils through the microbial processes of nitrifi cation and denitrification. Soil water content, temperature, texture, and carbon availability infl uence N2O emissions, but the strongest correlate is usually N inputs to the system, especially at large scales [Stehfest and Bouwman, 2006]. In addition to direct emissions, N inputs to agricultural soils also contribute to N2O emissions indirectly [IPCC, 2006] when nitrate that has leached or run off from soil is converted to N2O via aquatic denitrifi cation and when volatilized non‐N2O N‐oxides and ammonia are redeposited on soils and converted to N2O.
Paleointensity record from the 2.7 Ga Stillwater Complex, Montana
Authors: Selkin P. A. , Gee J. S. , Meurer W. P. , Hemming S. R.
Published: December 2008

The record of geomagnetic intensity captured in the 2.7 Ga Stillwater Complex (Montana, USA) provides a statistical description of the Archean geodynamo. We present results of modified Thellier paleointensity experiments on 441 core specimens, 114 of which pass strict reliability criteria. The specimens are from 53 sites spanning most of the Banded Series rocks in the Stillwater Complex. On the basis of thermochronologic and petrologic evidence, we interpret the highest temperature component of remanence to be a late Archean thermoremanence, though the possibility remains that it is a thermochemical remanence. Thermal models indicate that the highest temperature magnetization component at each of the sites averages ∼20–200 ka of geomagnetic secular variation. The suite of sites as distributed through the Banded Series samples a roughly a 1 Ma time interval. The average of the most reliable paleointensity measurements, uncorrected for the effects of anisotropy or cooling rate, is 38.2 ± 11.3 μT (1σ). Remanence anisotropy, cooling rate, and the nonlinear relationship between applied field and thermoremanence have a significant effect on paleointensity results; a corrected average of 30.6 ± 8.8 μT is likely a more appropriate value. Earth's average dipole moment during the late Archean (5.05 ± 1.46 × 1022 Am2, λpmag = 44.5°) was well within the range of estimates from Phanerozoic rocks. The distribution of site‐mean paleointensities around the mean is consistent with that expected from slow cooling over timescales expected from thermal models and with secular variation comparable to that of the Phanerozoic field.
Iron mineralogy and aqueous alteration from Husband Hill through Home Plate at Gusev Crater, Mars: Results from the Mössbauer instrument on the Spirit Mars Exploration Rover
Authors: Morris R. V. , Klingelhöfer G. , Schröder C. , Fleischer I. , Ming D. W. , Yen A. S. , Gellert R. , Arvidson R. E. , Rodionov D. S. , Crumpler L. S. , Clark B. C. , Cohen B. A. , McCoy T. J. , Mittlefehldt D. W. , Schmidt M. E. , de Souza P. A. , Squyres S. W.
Published: December 2008

Spirit's Mössbauer (MB) instrument determined the Fe mineralogy and oxidation state of 71 rocks and 43 soils during its exploration of the Gusev plains and the Columbia Hills (West Spur, Husband Hill, Haskin Ridge, northern Inner Basin, and Home Plate) on Mars. The plains are predominantly float rocks and soil derived from olivine basalts. Outcrops at West Spur and on Husband Hill have experienced pervasive aqueous alteration as indicated by the presence of goethite. Olivine‐rich outcrops in a possible mafic/ultramafic horizon are present on Haskin Ridge. Relatively unaltered basalt and olivine basalt float rocks occur at isolated locations throughout the Columbia Hills. Basalt and olivine basalt outcrops are found at and near Home Plate, a putative hydrovolcanic structure. At least three pyroxene compositions are indicated by MB data. MB spectra of outcrops Barnhill and Torquas resemble palagonitic material and thus possible supergene aqueous alteration. Deposits of Fe3+‐sulfate soil, located at Paso Robles, Arad, and Tyrone, are likely products of acid sulfate fumarolic and/or hydrothermal activity, possibly in connection with Home Plate volcanism. Hematite‐rich outcrops between Home Plate and Tyrone (e.g., Montalva) may also be products of this aqueous activity. Low water‐to‐rock ratios (isochemical alteration) are implied during palagonite, goethite, and hematite formation because bulk chemical compositions are basaltic (SO3‐free basis). High water‐to‐rock ratios (leaching) under acid sulfate conditions are implied for the high‐SiO2 rock and soil in Eastern Valley and the float rock FuzzySmith, which has possible pyrite/marcasite as a hydrothermal alteration product.
An explorative study of mercury export from a thawing palsa mire
Authors: Klaminder Jonatan , Yoo Kyungsoo , Rydberg Johan , Giesler Reiner
Published: December 2008

Thawing of permafrost and a subsequent accelerated loss of mercury from the soil constitute a possible threat to the quality of high‐latitude surface waters. In this paper we estimate the export of mercury generated by a thawing palsa mire in northern Sweden, by assessing net mercury storage changes along thermokarst erosion gradients. Lower mercury inventories in inundated hummocks covered by water (≤3.1 mg Hg m−2) than in noneroding hummocks (between 5.5 and 8 mg Hg m−2) suggests a release of ∼40–95% of the mercury pool from hummock peat experiencing subsidence and submerging. The documented expansion of submerged areas between 1970 and 2000 in the studied system indicates that permafrost thawing has initiated a mobilization of 34 to 50 g mercury. We stress the need of further assessing the fate of this mercury because the size of the mobilized mercury pool might be highly significant for subarctic surface waters.
Sea level rise, hydrologic runoff, and the flooding of Venice
Authors: Rinaldo A. , Nicótina L. , Alessi Celegon E. , Beraldin F. , Botter G. , Carniello L. , Cecconi G. , Defina A. , Settin T. , Uccelli A. , D'Alpaos L. , Marani M.
Published: December 2008

This paper deals with hydrologic studies relevant to the works engineered for the protection of the city of Venice (Italy) from major flooding under significant climate change scenarios. Such works foresee the temporary closure of the lagoon surrounding the city to tidal exchanges with the Adriatic Sea in times of sea storm surges via the operation of a set of mobile gates. A general hydrologic model of the ∼2000 km2 mainland contributing runoff to the lagoon of Venice is coupled in time and space with a 2‐D finite element model of the relevant tidal hydrodynamics to forecast maximum lagoonal surges in times of closure. We also study the impacts of run‐through discharges bypassing the mobile gates and wind setups at time scales comparable to the foreseen closures (from a few to tens of hours). Climate change scenarios are recapitulated by up to +50 cm relative sea level rises by 2100 (the projected lifetime of the current protection works). Possible flooding of the city due to residual fluxes entering the lagoon during prolonged closures is examined. A probabilistic framework is also proposed for computing the statistics of maximum lagoon rises and stage‐rise durations. Our studies suggest the adequacy of the design of temporary closures with respect to flooding and provide methods for general exercises in assessing the impact of regional climate change scenarios.
The hydrophobic motif of ROCK2 requires association with the N-terminal extension for kinase activity
Authors: Couzens Amber L. , Saridakis Vivian , Scheid Michael P.
Published: December 2008

ROCK (Rho-associated coiled-coil kinase) 2 is a member of the AGC kinase family that plays an essential role downstream of Rho in actin cytoskeleton assembly and contractility. The process of ROCK2 activation is complex and requires suppression of an autoinhibitory mechanism that is facilitated by Rho binding. ROCK2 harbours a C-terminal extension within the kinase domain that contains a hydrophobic cluster of phenylalanine and tyrosine residues surrounding a key threonine residue. In growth-factor-stimulated AGC kinases, the hydrophobic motif is important for the transition of the kinase from inactive to active complex and requires phosphorylation of the conserved serine/threonine residue. Less is understood about the contribution that the hydrophobic motif plays in the activation of ROCK, and the role of the hydrophobic motif threonine at position 405. In the present study, we show that this residue of ROCK is essential for substrate phosphorylation and kinase domain dimerization. However, in contrast with the growth-factor-activated AGC kinases, a phosphomimetic residue at position 405 was inhibitory for ROCK2 activity and dimerization. A soluble hydrophobic motif peptide allosterically activated ROCK2 In vitro, but not the equivalent peptide with Asp405 substitution. Mechanistically, both ROCK2 activity and dimerization were dependent upon the interaction between Thr405 of the hydrophobic motif and Asp39 of the N-terminal extension. The reciprocal exchange of these residues was permissive for kinase activity, but dimerization was lost. These results support the rationale for development of small-molecule inhibitors designed to block ROCK activation by selectively interfering with hydrophobic motif-mediated activation-state transition and dimer formation.
Nanogrowth twins and abnormal magnetic behavior in CoFe2O4 epitaxial thin films
Authors: Yan Li , Wang Yu , Li Jiefang , Pyatakov Alexander , Viehland D.
Published: December 2008

Nanogrowth twins (GTs) have been observed in CoFe2O4 (CFO) epitaxial thin films deposited on (111) oriented SrTiO3 substrates by pulsed laser deposition. The GTs form during nucleation and growth and consist of CFO growth regions that have a mirror relationship with respect to each other. We show that the films with GTs (i) are better crystallized than the ones without them and (ii) have higher saturation magnetizations due to the presence of twin boundaries.
Stability threshold of ion temperature gradient driven mode in reversed field pinch plasmas
Authors: Guo S. C.
Published: December 2008

For the first time in the reversed field pinch (RFP) configuration, the stability threshold of the ion temperature gradient driven (ITG) mode is studied by linear gyrokinetic theory. In comparison with tokamaks, the RFP configuration has a shorter connection length and stronger magnetic curvature drift. These effects result in a stronger instability driving mechanism and a larger growth rate in the fluid limit. However, the kinetic theory shows that the temperature slopes required for the excitation of ITG instability are much steeper than the tokamak ones. This is because the effect of Landau damping also becomes stronger due to the shorter connection length, which is dominant and ultimately determines the stability threshold. The required temperature slope for the instability may only be found in the very edge of the plasma and/or near the border of the dominant magnetic island during the quasi-single helicity state of discharge
Dust acoustic solitons in plasmas with kappa-distributed electrons and/or ions
Authors: Baluku T. K. , Hellberg M. A.
Published: December 2008

An investigation into both small and large amplitude dust acoustic solitary waves in dusty plasmas with cold negative dust grains and kappa-distributed ions and/or electrons is discussed. Existence conditions for the arbitrary amplitude case are found in an appropriate parameter space, viz., an effective Mach number of the structure speed and the fraction of the charge density that resides with the free electrons, expressed in terms of the ion density. Results indicate that the kappa distribution has only a quantitative, not a qualitative effect on the existence domains and only negative potential solitons exist regardless of whether the electrons or the ions, or both, have a kappa distribution. Despite a wide-ranging search, we have not found double layers in such a plasma. In the case of positive dust, an equivalent set of results holds.
Anisotropic Young’s modulus on magnetically ordered agarose gel
Authors: Fujimura Yuu , Tada Tomonari , Iino Masaaki
Published: December 2008

The static elasticity of magnetically ordered agarose gel has been studied. Young’s modulus gelled under strong magnetic fields and was measured outside of the magnetic field from the force-deformation relationships. Young’s modulus increased with magnetic field strength, particularly when the deformation was parallel to the magnetic field by a factor of 2. Young’s modulus and its anisotropy depend both on the concentration of gel as well as on the magnetic field. Assuming that the magnetic field dependence of the gel elasticity is mainly due to the magnetic change in entropic elasticity, we analyzed the domain ordering of agarose microquartz with microsyneresis in order to decide how to decrease entropy, which in turn would increase the elasticity. The anisotropic diamagnetic susceptibility of the domains was estimated to be (4.4±0.7)×10−23 emu for 1% gel and (1.35±0.20)×10−22 emu for 2% gel.
Metamaterial polarizers by electric-field-coupled resonators
Authors: Chin Jessie Y. , Lu Mingzhi , Cui Tie Jun
Published: December 2008

The idea of transmission polarizers realized by anisotropic metamaterials is demonstrated by experiments. One of the polarizers converts linear-polarized waves to circular-polarized waves, while the other polarizer converts linear-polarized waves from one polarization to its cross polarization. The excellent agreement between experimental results and theoretical predictions validates the functions and efficiency of the proposed polarizers.
Bipolar charge transport in poly(3-hexyl thiophene)/methanofullerene blends: A ratio dependent study
Authors: Baumann A. , Lorrmann J. , Deibel C. , Dyakonov V.
Published: December 2008

We investigated the charge carrier mobility in pristine poly(3-hexyl thiophene-2,5-diyl) (P3HT):[6,6]-phenyl-C61 butyric acid methyl ester (PCBM) blend devices by applying the time resolved photoconductivity experiment in dependence on the donor:acceptor ratio. We observe a bipolar transport in all studied samples ranging from pure polymer to polymer:fullerene with 90% PCBM content. For the ratios P3HT:PCBM 1:4 and 1:1 we observe two transit times in the electron current transients as well as hole double transients for P3HT:PCBM 1:2. We find high hole and electron mobilities in the order of 10−3–10−2cm2∕Vs for a concentration of 90% PCBM in the blend.
Abusing Multiculturalism: The Politics of Recognition and Land Allocation in Israel
Authors: Tzfadia Erez
Published: December 2008

The logic behind land allocation for residential purposes has undergone a dramatic shift in many states with a colonial legacy in the recent decade, from an ethnonational logic that favors the ethnonational majority to a more liberal-democratic, market-based logic that disregards ethnicity. In Israel, following this shift, a new claim for biased allocation has been voiced by the ethnonational majority, politicians, and administrators, which is based on multiculturalism and recognition. According to this claim, land allocation should serve the communal needs of the majority by limiting the access of minority groups to the majority group's residential areas. In this paper I argue that, despite the decline of ethnonationalism, the discourse of multiculturalism remains a substitute discourse that rationalizes the interests of the majority group, hence contributing to the stratification of societies on the basis of ethnicity. Through an analysis of three case studies of land allocation in Israel, the paper explores the material and cultural weaknesses of a multiculturalism that has been imported from societies with a strong liberal-democratic tradition into societies with a profound ethnonational legacy.
Taxonomic revision of Australasian snow hebes (Veronica, Plantaginaceae)
Authors: Meudt Heidi M.
Published: December 2008

The snow hebes, formerly comprising the genus Chionohebe, are here included within Veronica (Plantaginaceae). The five species (including two subspecies) of snow hebes recognised here are cushions or subshrubs that occur exclusively in high-elevation habitats of Australia and the South Island of New Zealand. Species delimitation among the cushion snow hebes is very difficult because of the reduced pulvinate habit, solitary flowers and few gross-morphological characters useful for identification. To address species limits, investigate intraspecific patterns and revise the taxonomy of the snow hebes, morphological analyses were conducted and the results compared with previously published molecular phylogenetic data. Ordination and clustering analyses of morphological data showed some taxonomic structuring; however, species clusters were not widely separated from one another. Morphological and amplified fragment length polymorphism (AFLP) data show that the cushion species are clearly distinguished from the subshrub species, V. densifolia (F.Muell.) F.Muell. Among the four cushion species (V. chionohebe Garn.-Jones, V. ciliolata (Hook.f.) Cheeseman, V. pulvinaris (Hook.f.) Cheeseman, V. thomsonii (Buchanan) Cheeseman), the distribution of leaf trichomes is important for species identification, particularly when used in conjunction with ovary vestiture, capsule size, and/or seed size. One new combination V. ciliolata subsp. fiordensis (Ashwin) Meudt is proposed, and V. uniflora Kirk is treated as a naturally occurring hybrid V. × uniflora (V. densifolia × V. thomsonii). Complete synonymies, descriptions, illustrations and range maps are provided for each species, as well as a key to all species and a discussion of putative hybrids.
Towards chunk-based translation memories
Authors: Colominas Carme
Published: December 2008

Most of the current Translation Memory systems are based on segments determined by marks that in most cases correspond to a complete sentence. The problem of complete sentence matching is that examples are often excluded from the matching candidates even though they probably contain one or more useful sub-segments that could be helpful to the translation.

In view of these limitations, some proposals have been made in the literature regarding the possibility of building Translation Memory systems that operate “below” the sentence level, that is to say, at a sub-sentential level. Existing work demonstrates that sub-sentential segmentation of Translation Memories clearly shows a significantly best recall with respect to sentential.segmentation.

Accepting the benefits of sub-sentential segmentation of Translation Memories, in this paper we consider different possibilities of sub sentential segmentation and attempt an evaluation of the recall (covering sequences of chunks) and the precision (usability of these chunks) obtained by noun phrase chunk segmentation.Our experiments show that pre- or postmodified NPs turn out to be especially adequate for pretranslation tasks tasks as they show a minimum cost by a maximum gain.. In other words, their translation is on the one side not trivial as it often involves structural divergences between language and at the same time they are context independent enough that they can be reused without changes in most cases.
No creativity in legal translation?
Authors: Pommer Sieglinde E.
Published: December 2008

Whereas translating is generally considered to be a creative activity, mentioning this in the context of legal translation is, rather paradoxically, widely frowned upon despite the fact that the ­incongruency of legal systems makes finding exact equivalents particularly difficult in legal texts.

Convinced that in fact translating the law requires taking insightful judgments, detecting interesting alternatives, coming up with novel ways to communicate ideas, and finding useful ­solutions to complex problems, the author examines the dynamic concept of creativity and redefines its meaning with regard to legal translation.
Convergence of weighted polynomial multiple ergodic averages
Authors: Chu Qing
Published: December 2008

In this article we study weighted polynomial multiple ergodic averages. A sequence of weights is called universally good if any polynomial multiple ergodic average with this sequence of weights converges in

L

2

L^{2}

. We find a necessary condition and show that for any bounded measurable function

ϕ
\phi

on an ergodic system, the sequence

ϕ
(

T

n

x
)

\phi (T^{n}x)

is universally good for almost every

x
x

. The linear case was covered by Host and Kra.
A short proof of Pitt’s compactness theorem
Authors: Delpech Sylvain
Published: December 2008

We give a short proof of Pitt’s theorem that every bounded linear operator from

ℓ
p

\ell _p

or

c
0

c_0

into

ℓ
q

\ell _q

is compact whenever

1
≤
q
>
p
>
∞

1\leq q>p>\infty

.
An algebraic independence result for Euler products of finite degree
Authors: Zaharescu Alexandru , Zaki Mohammad
Published: December 2008

We investigate the algebraic independence of some derivatives of certain multiplicative arithmetical functions over the field

C

\mathbb {C}

of complex numbers.
Piecewise contractions are asymptotically periodic
Authors: Bruin Henk , Deane Jonathan
Published: December 2008

We show that, given a finite partition of the plane

C

\mathbb {C}

such that the map

G
G

acts as a linear contraction on each part, for almost every choice of parameters every orbit of

G
G

is (asymptotically) periodic.
Analyticity of the SRB measure for holomorphic families of quadratic-like Collet-Eckmann maps
Authors: Baladi Viviane , Smania Daniel
Published: December 2008

We show that ifftf_tis a holomorphic family of quadratic-like maps with all periodic orbits repelling so that for each realttthe mapftf_tis a real Collet-EckmannSS-unimodal map, then, writingμt\mu _tfor the unique absolutely continuous invariant probability measure offtf_t, the map\[t↦∫ψdμtt\mapsto \int \psi \, d\mu _t\]is real analytic for any real analytic functionψ\psi.
Producing set-theoretic complete intersection monomial curves in ℙⁿ
Authors: Şahi̇n Mesut
Published: December 2008

In this paper we describe an algorithm for producing infinitely many examples of set-theoretic complete intersection monomial curves in

P

n
+
1

\mathbb {P}^{n+1}

, starting with a single set-theoretic complete intersection monomial curve in

P

n

\mathbb {P}^{n}

. Moreover we investigate the numerical criteria to decide when these monomial curves can or cannot be obtained via semigroup gluing.
Pfister’s theorem for orthogonal involutions of degree 12
Authors: Garibaldi Skip , Quéguiner-Mathieu Anne
Published: December 2008

We use the fact that a projective half-spin representation of

Spin

12

\operatorname {Spin}_{12}

has an open orbit to generalize Pfister’s result on quadratic forms of dimension 12 in

I
3

I^3

to orthogonal involutions.
A lower bound for the Chung-Diaconis-Graham random process
Authors: Hildebrand Martin
Published: December 2008

Chung, Diaconis, and Graham considered random processes of the form

X

n
+
1

=

a
n

X
n

+

b
n

(
mod

p
)

X_{n+1}=a_nX_n+b_n\pmod p

where

p
p

is odd,

X
0

=
0

X_0=0

,

a
n

=
2

a_n=2

always, and

b
n

b_n

are i.i.d. for

n
=
0
,
1
,
2
,
…

n=0,1,2,\dots

. In this paper, we show that if
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper P left-parenthesis b Subscript n Baseline equals negative 1 right-parenthesis equals upper P left-parenthesis b Subscript n Baseline equals 0 right-parenthesis equals upper P left-parenthesis b Subscript n Baseline equals 1 right-parenthesis equals 1 slash 3">

P
(

b
n

=
−
1
)
=
P
(

b
n

=
0
)
=
P
(

b
n

=
1
)
=
1

/

3

P(b_n=-1)=P(b_n=0)=P(b_n=1)=1/3

, then there exists a constant

c
>
1

c>1

such that

c

log
2

⁡
p

c\log _2p

steps are not enough to make

X
n

X_n

get close to being uniformly distributed on the integers mod

p
p

.
Multiples of hypercyclic operators
Authors: Badea Catalin , Grivaux Sophie , Müller Vladimir
Published: December 2008

We give a negative answer to a question of Prăjitură by showing that there exists an invertible bilateral weighted shift

T
T

on

ℓ
2

(

Z

)

\ell _2(\mathbb {Z})

such that

T
T

and

3
T

3T

are hypercyclic but

2
T

2T

is not. Moreover, any

G
δ

G_\delta

set

M
⊆
(
0
,
∞
)

M \subseteq (0,\infty )

which is bounded and bounded away from zero can be realized as

M
=
{
t
>
0
∣
t
T

 is hypercyclic

}

M=\{t>0 \mid tT \textrm { is hypercyclic}\}

for some invertible operator

T
T

acting on a Hilbert space.
On the localization principle for the automorphisms of pseudoellipsoids
Authors: Landucci Mario , Spiro Andrea
Published: December 2008

We show that Alexander’s extendibility theorem for a local automorphism of the unit ball is valid also for a local automorphism

f
f

of a pseudoellipsoid
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="script upper E Subscript left-parenthesis p 1 comma ellipsis comma p Sub Subscript k Subscript right-parenthesis Superscript n Baseline equals Overscript def Endscripts StartSet z element-of double-struck upper C Superscript n Baseline colon sigma-summation Underscript j equals 1 Overscript n minus k Endscripts StartAbsoluteValue z Subscript j Baseline EndAbsoluteValue squared plus StartAbsoluteValue z Subscript n minus k plus 1 Baseline EndAbsoluteValue Superscript 2 p 1 Baseline plus midline-horizontal-ellipsis plus StartAbsoluteValue z Subscript n Baseline EndAbsoluteValue Superscript 2 p Super Subscript k Superscript Baseline greater-than 1 EndSet">

E

(

p
1

,
…
,

p

k

)

n

=
def

{
z
∈

C

n

:

∑

j
=
1

n
−
k

|

z
j

|

2

+

|

z

n
−
k
+
1

|

2

p
1

+
⋯
+

|

z
n

|

2

p

k

>
1
}

\mathcal {E}^n_{(p_1, \dots , p_{k})}\overset {\text {def}}{=} \{ z \in \mathbb {C}^n : \sum _{j= 1}^{n - k}|z_j|^2 + |z_{n-k+1}|^{2 p_1} + \dots + |z_n|^{2 p_{k}} > 1\}

, provided that

f
f

is defined on a region

U

⊂

E

(
p
)

n

\mathcal {U} \subset \mathcal {E}^n_{(p)}

such that: i)

∂

U

∩
∂

E

(
p
)

n

\partial \mathcal {U} \cap \partial \mathcal {E}^n_{(p)}

contains an open set of strongly pseudoconvex points; ii)

U

∩
{

z
i

=
0
}
≠
∅

\mathcal {U}\cap \{ z_i = 0 \} \neq \emptyset

for any

n
−
k
+
1
≤
i
≤
n

n-k +1 \leq i \leq n

. By the counterexamples we exhibit, such hypotheses can be considered as optimal.
A family of local rings with rational Poincaré series
Authors: Elias Juan , Valla Giuseppe
Published: December 2008

In this note we compute the Poincaré series of almost stretched Gorenstein local rings. It turns out that it is rational.
The bounding genera and 𝑤-invariants
Authors: Fukumoto Yoshihiro
Published: December 2008

In this paper, we give an estimate from below of the bounding genera for homology

3
3

-spheres defined by Y. Matsumoto in terms of

w
w

-invariants. In particular, combining with Matsumoto’s estimates we determine the values of the bounding genera for several infinite families of Brieskorn homology

3
3

-spheres.
On the discrete heat equation taking values on a tree
Authors: Mueller Carl , Lee Kijung
Published: December 2008

This paper was motivated by the question of studying PDE or stochastic PDE taking values on nonsmooth spaces. This is a hard problem in general, so we concentrate on a test case: the heat equation taking values on the union of rays emanating from the origin. We construct a series of discrete approximation to the solution and show that they converge to a limit. Unfortunately, we do not know if the limit is uniqueness. Our tools are probabilistic, exploiting the well-known connection between Brownian motion and the heat equation.
Totally free arrangements of hyperplanes
Authors: Abe Takuro , Terao Hiroaki , Yoshinaga Masahiko
Published: December 2008

A central arrangement

A

\mathcal {A}

of hyperplanes in an

ℓ
\ell

-dimensional vector space

V
V

is said to be totally free if a multiarrangement

(

A

,
m
)

(\mathcal {A}, m)

is free for any multiplicity

m
:

A

→

Z

>
0

m : \mathcal {A}\rightarrow \mathbb {Z} _{> 0}

. It has been known that

A

\mathcal {A}

is totally free whenever

ℓ
≤
2

\ell \le 2

. In this article, we will prove that there does not exist any totally free arrangement other than the obvious ones, that is, a product of one-dimensional arrangements and two-dimensional ones.
Can sugars be produced from fatty acids? A test case for pathway analysis tools
Authors: de Figueiredo Luis F. , Schuster Stefan , Kaleta Christoph , Fell David A.
Published: December 2008

Motivation: In recent years, several methods have been proposed for determining metabolic pathways in an automated way based on network topology. The aim of this work is to analyse these methods by tackling a concrete example relevant in biochemistry. It concerns the question whether even-chain fatty acids, being the most important constituents of lipids, can be converted into sugars at steady state. It was proved five decades ago that this conversion using the Krebs cycle is impossible unless the enzymes of the glyoxylate shunt (or alternative bypasses) are present in the system. Using this example, we can compare the various methods in pathway analysis.

Results: Elementary modes analysis (EMA) of a set of enzymes corresponding to the Krebs cycle, glycolysis and gluconeogenesis supports the scientific evidence showing that there is no pathway capable of converting acetyl-CoA to glucose at steady state. This conversion is possible after the addition of isocitrate lyase and malate synthase (forming the glyoxylate shunt) to the system. Dealing with the same example, we compare EMA with two tools based on graph theory available online, PathFinding and Pathway Hunter Tool. These automated network generating tools do not succeed in predicting the conversions known from experiment. They sometimes generate unbalanced paths and reveal problems identifying side metabolites that are not responsible for the carbon net flux. This shows that, for metabolic pathway analysis, it is important to consider the topology (including bimolecular reactions) and stoichiometry of metabolic systems, as is done in EMA.

Contact:  ldpf@minet.uni-jena.de; schuster@minet.uni-jena.de

Supplementary information:  Supplementary data are available at Bioinformatics online.
Systematic review: the extra‐oesophageal symptoms of gastro‐oesophageal reflux disease in children
Authors: TOLIA V. , VANDENPLAS Y.
Published: December 2008

Background  Extra‐oesophageal symptoms are thought to be common, atypical symptoms of gastro‐oesophageal reflux disease (GERD) in children.

Aim  To investigate the prevalence of GERD in children with extra‐oesophageal symptoms or of extra‐oesophageal symptoms in children with GERD, and the effect of GERD therapies on extra‐oesophageal symptoms.

Methods  A systematic review of articles in PubMed and EMBASE.

Results  We identified 18 relevant articles. The pooled weighted average prevalence of GERD in asthmatic children was 23%, compared with 4% in healthy controls from the same five studies. The majority of studies evaluating the relationship between apparent life‐threatening event (ALTE) and GERD did not suggest a causal relationship. Seven studies reported that respiratory symptoms, sinusitis and dental erosion were significantly more prevalent in children with GERD than in controls. Data from pharmacotherapeutic trials were inconclusive and provided no support for a causal relationship between GERD and extra‐oesophageal symptoms.

Conclusions  Possible associations exist between GERD and asthma, pneumonia, bronchiectasis, ALTE, laryngotracheitis, sinusitis and dental erosion, but causality or temporal association were not established. Moreover, the paucity of studies, small sample sizes and varying disease definitions did not allow firm conclusions to be drawn. Most trials of GERD therapies showed no improvement in extra‐oesophageal symptoms in children.
Biomarkers for the effects of cannabis and THC in healthy volunteers
Authors: Zuurman Lineke , Ippel Annelies E. , Moin Eduard , Van Gerven Joop M. A.
Published: December 2008

An increasing number of novel therapeutic agents are targeted at cannabinoid receptors. Drug development programmes of new cannabinoid drugs may be facilitated by the identification of useful biomarkers. This systemic literature review aims to assess the usefulness of direct biomarkers for the effects of cannabis and tetrahydrocannabinol (THC) in healthy volunteers. One hundred and sixty‐five useful articles were found that investigated the acute effects of cannabis or THC on the central nervous system (CNS) and heart rate in healthy volunteers. Three hundred and eighteen tests (or test variants) were grouped in test clusters and functional domains, to allow their evaluation as a useful biomarker and to study their dose–response effects. Cannabis/THC affected a wide range of CNS domains. In addition to heart rate, subjective effects were the most reliable biomarkers, showing significant responses to cannabis in almost all studies. Some CNS domains showed indications of depression at lower and stimulation at higher doses. Subjective effects and heart rate are currently the most reliable biomarkers to study the effect of cannabis. Cannabis affects most CNS domains, but too many different CNS tests are used to quantify the drug–response relationships reliably. Test standardization, particularly in motor and memory domains, may reveal additional biomarkers.
Suppression of allergic airway inflammation in a mouse model by Der p2 recombined BCG
Authors: Ou‐Yang Hai‐Feng , Hu Xing‐Bin , Ti Xin‐Yu , Shi Jie‐Ran , Li Shu‐Jun , Qi Hao‐Wen , Wu Chang‐Gui
Published: December 2008

Allergic asthma is a chronic inflammatory disease mediated by T helper (Th)2 cell immune responses. Currently, immunotherapies based on both immune deviation and immune suppression, including the development of recombinant mycobacteria as immunoregulatory vaccines, are attractive treatment strategies for asthma. In our previous studies, we created a genetically recombinant form of bacille Calmette–Guerin (rBCG) that expressed Der p2 of house dust mites and established that it induced a shift from a Th2 response to a Th1 response in naive mice. However, it is unclear whether rBCG could suppress allergic airway inflammation in a mouse model. In this article we report that rBCG dramatically inhibited airway inflammation, eosinophilia, mucus production and mast cell degranulation in allergic mice. Analysis of interferon‐γ (IFN‐γ) and interleukin‐4 (IL‐4) levels in bronchoalveolar lavage fluid (BALF) and lung tissue revealed that the suppression was associated with a shift from a Th2 response to a Th1 response. At the same time, rBCG induced a CD4+ CD25+ Foxp3+ T‐cell subtype that could suppress the proliferation of Th2 effector cells in vitro in an antigen‐specific manner. Moreover, suppression of CD4+ CD25+ T cells could be adoptively transferred. Thus, our results demonstrate that rBCG induces both generic and specific immune responses. The generic immune response is associated with a shift from a Th2 to a Th1 cytokine response, whereas the specific immune response against Der p2 appears to be related to the expansion of transforming growth factor‐β (TGF‐β)‐producing CD4+ CD25+ Foxp3+ regulatory T cells. rBCG can suppress asthmatic airway inflammation through both immune deviation and immune suppression and may be a feasible, efficient immunotherapy for asthma.
Virulence, immunopathology and transmissibility of selected strains ofMycobacterium tuberculosisin a murine model
Authors: Marquina‐Castillo Brenda , García‐García Lourdes , Ponce‐de‐León Alfredo , Jimenez‐Corona Maria‐Eugenia , Bobadilla‐del Valle Miriam , Cano‐Arellano Bulmaro , Canizales‐Quintero Sergio , Martinez‐Gamboa Areli , Kato‐Maeda Midori , Robertson Brian , Young Douglas , Small Peter , Schoolnik Gary , Sifuentes‐Osornio Jose , Hernandez‐Pando Rogelio
Published: December 2008

After encounter withMycobacterium tuberculosis, a series of non‐uniform immune responses are triggered that define the course of the infection. EightM. tuberculosisstrains were selected from a prospective population‐based study of pulmonary tuberculosis patients (1995–2003) based on relevant clinical/epidemiological patterns and tested in a well‐characterized BALB/c mouse model of progressive pulmonary tuberculosis. In addition, a new mouse model of transmissibility consisting of prolonged cohousing (up to 60 days) of infected and naïve animals was tested. Four phenotypes were defined based on strain virulence (mouse survival, lung bacillary load and tissue damage), immunology response (cytokine expression determined by real‐time polymerase chain reaction) and transmissibility (lung bacillary loads and cutaneous delayed‐type hypersensitivity in naïve animals).We identified four clearly defined strain phenotypes: (1) hypervirulent strain with non‐protective immune response and highly transmissible; (2) virulent strain, associated with high expression of proinflammatory cytokines (tumour necrosis factor and interferon) and very low anti‐inflammatory cytokine expression (interleukins 4 and 10), which induced accelerated death by immunopathology; (3) strain inducing efficient protective immunity with lower virulence, and (4) strain demonstrating strong and early macrophage activation (innate immunity) with delayed participation of acquired immunity (interferon expression). We were able to correlate virulent and transmissible phenotypes in the mouse model and markers of community transmission such as tuberculin reactivity among contacts, rapid progression to disease and cluster status. However, we were not able to find correlation with the other two phenotypes. Our new transmission model supported the hypothesis that among these strains increased virulence was linked to increased transmission.
Testicular microlithiasis and carcinomain situoverview and proposed clinical guideline
Authors: Van Casteren N. J. , Looijenga L. H. J. , Dohle G. R.
Published: December 2008

Testicular microlithiasis (TM) has been associated with testicular germ cell tumours (TGCTs) in adolescents and adults and with its precursor carcinomain situ(CIS). A clear definition of TM and the need for further diagnostics and follow‐up is lacking. We reviewed the literature of TM and its association with TGCT/CIS and current follow‐up advises and propose a management approach based on associated risk factors for TGCT. In the literature, a wide variance of TM incidence is reported in different patient populations. A consensus concerning the malignant potential of TM has not been reached. In addition, a clear definition on TM is lacking. Although a correlation between TM and TGCT or CIS is found, precise management and follow‐up schedules are absent. We suggest that all hyperechogenic foci smaller than 3 mm without shadowing should be named TM irrespective of their number. In addition, we suggest a management scheme for physicians encountering TM in daily practice. Our algorithm suggests taking a testicular biopsy in a selected patient population with at least one additional risk factor for TGCT. A long‐term active follow‐up schedule, including ultrasonography and physical examinations, is not indicated in the remaining patients with TM.
Androgen receptor gene polymorphism and the metabolic syndrome in 60–80 years old Norwegian men
Authors: Skjærpe Paal André , Giwercman Yvonne L. , Giwercman Aleksander , Svartberg Johan
Published: December 2008

The metabolic syndrome (MS) includes a clustering of metabolic derangements. Low testosterone levels have been shown to be associated with both components of MS and MS per se. As most androgen‐related effects are mediated thorough the androgen receptor (AR), we wanted to investigate to which degree the AR CAG and GGN repeat polymorphisms might be related to MS. Sixty‐eight men, 60–80 years old, with subnormal total testosterone levels (≤11.0 nmol/L) and 104 men with normal levels (>11.0 nmol/L), participating in a nested case–control study were investigated in this study. Body weight, height, waist circumferences and blood pressure were measured. Fasting blood samples were drawn and an oral glucose tolerance test (OGTT) was performed. The CAG and GGN polymorphisms in the AR gene were determined by direct sequencing of leucocyte DNA. Men with MS had lower CAG repeat number than healthy men (p = 0.007). There were, however, no difference in CAG or GGN repeats length between the groups with subnormal or normal testosterone concentrations. In cross‐sectional analyses, men with CAG repeat lengths ≤ 21 had significantly higher fasting glucose, C‐peptide and glycosylated haemoglobin (HbA1c) levels (all p < 0.05). In multiple regression analyses, CAG repeat length was an inverse and independent predictor of glucose after an OGTT and of HbA1c levels. We also found that men with more than one component of MS had shorter CAG repeat number (p for trend 0.013) than those with only one component. In conclusion, there were no associations with GGN repeat length, while short CAG repeat length seems to be associated with increased risk of MS.
Partial inhibition of cholesterol oxides formation in frozen fish pre‐treated with a plant extract
Authors: Lebovics Vera , Lugasi Andrea , Hóvari Judit , Aubourg Santiago P.
Published: December 2008

The formation of cholesterol oxide products (COPs) in frozen horse mackerel (Trachurus trachurus) fillets was studied. The effect of pre‐treating the fish by soaking (45 min) in either of two concentrations of the aqueous solution of an antioxidant plant extract prior to the freezing step was determined. The fish fillets were sampled immediately after freezing and at intervals along 12 months of frozen storage (−20 °C). Two control groups consisting of untreated and water‐treated fish were stored and sampled under the same conditions. During the experiment, qualitative analysis revealed the formation of the following COPs: 7α‐hydroxy‐cholesterol, 7β‐hydroxy‐cholesterol and 7‐keto‐cholesterol. All treatment groups showed an increase (P < 0.05) in the content of all three COPs with storage time. As a result of pre‐freezing antioxidant treatment, COPs formation was reduced (P < 0.05) in comparison with both control samples. This partial inhibition was consistent with a longer shelf‐life time as revealed by sensory analysis.
Climatic change as an engine for speciation in flightless Orthoptera species inhabiting African mountains
Authors: VOJE KJETIL LYSNE , HEMP CLAUDIA , FLAGSTAD ØYSTEIN , SÆTRE GLENN‐PETER , STENSETH NILS CHR.
Published: December 2008

Many East African mountains are characterized by an exceptionally high biodiversity. Here we assess the hypothesis that climatic fluctuations during the Plio‐Pleistocene led to ecological fragmentation with subsequent genetic isolation and speciation in forest habitats in East Africa. Hypotheses on speciation in savannah lineages are also investigated. To do this, mitochondrial DNA sequences from a group of bush crickets consisting of both forest and savannah inhabiting taxa were analysed in relation to Plio‐Pleistocene range fragmentations indicated by palaeoclimatic studies. Coalescent modelling and mismatch distributions were used to distinguish between alternative biogeographical scenarios. The results indicate two radiations: the earliest one overlaps in time with the global spread of C4 grasslands and only grassland inhabiting lineages originated in this radiation. Climatically induced retraction of forest to higher altitudes about 0.8 million years ago, promoting vicariant speciation in species inhabiting the montane zone, can explain the second radiation. Although much of the biodiversity in East Africa is presently threatened by climate change, past climatic fluctuations appear to have contributed to the species richness observed in the East African hot spots. Perceiving forests as centres of speciation reinforces the importance of conserving the remaining forest patches in the region.
Independent colonization and extensive cryptic speciation of freshwater amphipods in the isolated groundwater springs of Australia's Great Artesian Basin
Authors: MURPHY NICHOLAS P. , ADAMS MARK , AUSTIN ANDREW D.
Published: December 2008

The groundwater‐dependent springs of the Great Artesian Basin (GAB) in arid inland Australia represent a unique and threatened ecosystem. These incredibly isolated springs support a diverse array of endemic flora and fauna. One of the common faunal groups in the GAB springs is the freshwater amphipods of the family Chiltoniidae. The morphological conservatism and taxonomic uncertainty associated with these amphipods has ensured their true biodiversity, phylogeographical history and evolutionary affinities have remained unknown. We have used mitochondrial DNA and allozyme data to unravel a complicated history of isolation, extinction and dispersal among spring amphipod populations across the GAB. The results provide evidence for multiple independent colonizations in the GAB springs, particularly within the Lake Eyre group of springs. The inclusion of a group of Western Australian (WA) stygobitic amphipods from populations up to 1500 km away found surprising evidence for a shared evolutionary history between stygobitic and GAB spring amphipods. Approximate dating of the diversity found between major clades suggests the majority of lineages originated in the late Miocene, around the time of the aridification of inland Australia. The large number of independent lineages and the close connection between GAB spring and WA stygobitic amphipods suggest that a significantly rich amphipod fauna existed in the much wetter environment that once existed in inland Australia. The results also provide evidence for a gross underestimation of the species diversity within the springs, with 12 putative species identified, a conclusion with significant implications for the ongoing conservation of the GAB springs.