bluuebunny/crossref_metadata_2025_split huggingface dataset:
Commutator maps, measure preservation, and 𝑇-systems
Authors: Garion Shelly , Shalev Aner 
Published: May 2009

Let

G
G

be a finite simple group. We show that the commutator map

α
:
G
×
G
→
G

\alpha :G \times G \rightarrow G

is almost equidistributed as

|

G

|

→
∞

|G| \rightarrow \infty

. This somewhat surprising result has many applications. It shows that a for a subset

X
⊆
G

X \subseteq G

we have

α

−
1

(
X
)

/

|

G

|

2

=

|

X

|

/

|

G

|

+
o
(
1
)

\alpha ^{-1}(X)/|G|^2 = |X|/|G| + o(1)

, namely

α
\alpha

is almost measure preserving. From this we deduce that almost all elements

g
∈
G

g \in G

can be expressed as commutators

g
=
[
x
,
y
]

g = [x,y]

where

x
,
y

x,y

generate

G
G

.

This enables us to solve some open problems regarding

T
T

-systems and the Product Replacement Algorithm (PRA) graph. We show that the number of

T
T

-systems in

G
G

with two generators tends to infinity as

|

G

|

→
∞

|G| \rightarrow \infty

. This settles a conjecture of Guralnick and Pak. A similar result follows for the number of connected components of the PRA graph of

G
G

with two generators.

Some of our results apply for more general finite groups and more general word maps.

Our methods are based on representation theory, combining classical character theory with recent results on character degrees and values in finite simple groups. In particular the so called Witten zeta function

ζ
G

(
s
)
=

∑

χ
∈
Irr
⁡
(
G
)

χ
(
1

)

−
s

\zeta ^G(s) = \sum _{\chi \in \operatorname {Irr}(G)}\chi (1)^{-s}

plays a key role in the proofs.
Elliptic equations with critical growth and a large set of boundary singularities
Authors: Ghoussoub Nassif , Robert Frédéric 
Published: May 2009

We solve variationally certain equations of stellar dynamics of the form

−

∑
i

∂

i
i

u
(
x
)
=

|

u

|

p
−
2

u
(
x
)

dist

(
x
,

A

)
s

-\sum _i\partial _{ii} u(x) =\frac {|u|^{p-2}u(x)}{\textrm {dist} (x,{\mathcal A} )^s}

in a domain

Ω
\Omega

of

R

n

\mathbb {R}^n

, where

A

{\mathcal A}

is a proper linear subspace of

R

n

\mathbb {R}^n

. Existence problems are related to the question of attainability of the best constant in the following inequality due to Maz’ya (1985):
\[

0
>

μ

s
,

P

(
Ω
)
=
inf

{

∫

Ω

|

∇
u

|

2

d
x

|

u
∈

H

1
,
0

2

(
Ω
)

a
n
d

∫

Ω

|

u
(
x
)

|

2

⋆

(
s
)

|

π
(
x
)

|

s

d
x
=
1

}

,

0>\mu _{s,\mathcal {P}}(\Omega ) =\inf \left \{\int _{\Omega }|\nabla u|^2 dx\; \left |\; u\in H_{1,0}^2(\Omega ) \;\mathrm { and }\; \int _{\Omega }\frac {|u(x)|^{2^{\star }(s)}}{|\pi (x)|^s} dx=1\right .\right \},

\]
where

0
>
s
>
2

0>s>2

,

2

⋆

(
s
)
=

2
(
n
−
s
)

n
−
2

2^{\star }(s) =\frac {2(n-s)}{n-2}

and where

π
\pi

is the orthogonal projection on a linear space

P

\mathcal {P}

, where

dim

R

⁡

P

≥
2

\operatorname {dim}_{\mathbb {R}}\mathcal {P}\geq 2

(see also Badiale-Tarantello (2002)). We investigate this question and how it depends on the relative position of the subspace

P

⊥

{\mathcal P}^{\bot }

, the orthogonal of

P

\mathcal P

, with respect to the domain

Ω
\Omega

, as well as on the curvature of the boundary

∂
Ω

\partial \Omega

at its points of intersection with

P

⊥

{\mathcal P}^{\bot }

.
Predictor correlation impacts machine learning algorithms: implications for genomic studies
Authors: Nicodemus Kristin K. , Malley James D. 
Published: May 2009

Abstract
Motivation: The advent of high-throughput genomics has produced studies with large numbers of predictors (e.g. genome-wide association, microarray studies). Machine learning algorithms (MLAs) are a computationally efficient way to identify phenotype-associated variables in high-dimensional data. There are important results from mathematical theory and numerous practical results documenting their value. One attractive feature of MLAs is that many operate in a fully multivariate environment, allowing for small-importance variables to be included when they act cooperatively. However, certain properties of MLAs under conditions common in genomic-related data have not been well-studied—in particular, correlations among predictors pose a problem.
Results: Using extensive simulation, we showed considering correlation within predictors is crucial in making valid inferences using variable importance measures (VIMs) from three MLAs: random forest (RF), conditional inference forest (CIF) and Monte Carlo logic regression (MCLR). Using a case–control illustration, we showed that the RF VIMs—even permutation-based—were less able to detect association than other algorithms at effect sizes encountered in complex disease studies. This reduction occurred when ‘causal’ predictors were correlated with other predictors, and was sharpest when RF tree building used the Gini index. Indeed, RF Gini VIMs are biased under correlation, dependent on predictor correlation strength/number and over-trained to random fluctuations in data when tree terminal node size was small. Permutation-based VIM distributions were less variable for correlated predictors and are unbiased, thus may be preferred when predictors are correlated. MLAs are a powerful tool for high-dimensional data analysis, but well-considered use of algorithms is necessary to draw valid conclusions.
Contact: kristin.nicodemus@well.ox.ac.uk
Supplementary information: Supplementary data are available at Bioinformatics online.
Bisoprolol in patients with heart failure and moderate to severe chronic obstructive pulmonary disease: a randomized controlled trial
Authors: Hawkins Nathaniel M. , MacDonald Michael R. , Petrie Mark C. , Chalmers George W. , Carter Roger , Dunn Francis G. , McMurray John J.V. 
Published: May 2009

AimsHeart failure (HF) and chronic obstructive pulmonary disease (COPD) frequently coexist. No study has prospectively examined the effects of beta‐blockade in those with both conditions.Methods and resultsWe randomized 27 patients with HF and coexistent moderate or severe COPD to receive bisoprolol or placebo, titrated to maximum tolerated dose over 4 months. The primary outcome was forced expiratory volume in 1 s (FEV1). The study is registered with ClinicalTrials.gov, number: NCT00702156. Patients were elderly and predominantly male. Cardiovascular comorbidity, smoking history, and pulmonary function were similar in each group (mean FEV1 1.37 vs. 1.26 L, P = 0.52). A reduction in FEV1 occurred after 4 months following treatment with bisoprolol compared with placebo (−70 vs. +120 mL, P = 0.01). Reversibility following inhaled β2‐agonist and static lung volumes were not impaired by bisoprolol. All measures of health status exhibited a consistent non‐significant improvement, including the Short Form 36 physical and mental component scores (2.6 vs. 0.5 and 0.8 vs. −0.3, respectively), Minnesota Living with Heart Failure Questionnaire (−2.5 vs. 3.5) and Chronic Respiratory Questionnaire (0.07 vs. −0.24). The mean number of COPD exacerbations was similar in the bisoprolol and placebo groups (0.50 and 0.31, respectively, P = 0.44).ConclusionInitiation of bisoprolol in patients with HF and concomitant moderate or severe COPD resulted in a reduction in FEV1. However, symptoms and quality of life were not impaired.
Temporal trends in stock origin and abundance of juvenile herring (Clupea harengus) in the Irish Sea
Authors: Burke Nóirín , Brophy Deirdre , Schön Pieter-Jan , King Pauline A. 
Published: May 2009

Abstract
Burke, N., Brophy, D., Schön, P-J., and King, P. A. 2009. Temporal trends in stock origin and abundance of juvenile herring (Clupea harengus) in the Irish Sea. – ICES Journal of Marine Science, 66: 1749–1753. Celtic Sea herring (Clupea harengus) larvae partly disperse into the Irish Sea, where they mix with the resident stock during their first year of life. This affects the reliability of the use of acoustic estimates of juvenile abundance on the Irish Sea nursery grounds as a recruitment index for use in stock predictions. Otolith microstructure analysis can be used to distinguish between autumn-spawned and winter-spawned individuals. Because winter spawners do not occur in the Irish Sea, this component can be assigned to Celtic Sea immigrants. We used this method to estimate the proportion of winter-spawned individuals in samples of age-1 herring from the western Irish Sea over a 10-year period (1993–2003), and subtracted a corresponding proportion from the acoustic age-1 abundance estimates. The adjusted index for autumn-spawned (supposedly Irish Sea) juveniles was significantly correlated with the abundance of age-3 fish from the same year class in commercial catches and in the acoustic surveys (p < 0.05 and <0.01, respectively), whereas the correlations for unadjusted indices were not significant. These findings are discussed in relation to the monitoring and assessment of herring in the two areas.
Effects of Protease and Urea on a Granular Starch Hydrolyzing Process for Corn Ethanol Production
Authors: Wang Ping , Johnston David B. , Rausch Kent D. , Schmidt Shelly J. , Tumbleson M. E. , Singh Vijay 
Published: May 2009

ABSTRACTThe dry grind process using granular starch hydrolyzing enzymes (GSHE) saves energy. The amount of GSHE used is an important factor affecting dry grind process economics. Proteases can weaken protein matrix to aid starch release and may reduce GSHE doses. Two specific proteases, an exoprotease and an endoprotease, were evaluated in the dry grind process using GSHE (GSH process). The effect of protease and urea addition on GSH process was also evaluated. Addition of these proteases resulted in higher ethanol concentrations (mean increase of 0.3–1.8 v/v) and lower distillers' dried grains with solubles (DDGS) yields (mean decrease of 1.3–8.0% db) compared with the control (no protease addition). As protease levels and GSHE increased, ethanol concentrations increased and DDGS yields decreased. Protease addition reduced the required GSHE dose. Final mean ethanol concentrations without urea (15.2% v/v) were higher than with urea (15.0% v/v) in GSH process across all protease treatments.
Development of an Ethanol Yield Procedure for Dry‐Grind Corn Processing
Authors: Lemuz Carlos R. , Dien Bruce S. , Singh Vijay , McKinney John , Tumbleson M. E. , Rausch Kent D. 
Published: May 2009

ABSTRACTIn 2008, the United States produced ethanol at a rate of 39.5 billion L/year; an additional 8.5 billion L/year capacity was under construction. Kernel composition and physical properties are not correlated with ethanol yield. A procedure that measured the potential of hybrids to produce ethanol would benefit corn seed companies, corn producers, and ethanol processors. The objective was to develop a laboratory procedure to measure ethanol yield from corn samples and evaluate the developed procedure for accuracy and precision. To determine parameters for routine analyses, effects of mill type, dry solids, and yeast addition were investigated separately followed by effects of fermentation time (Tf), glucoamylase dose, and yeast addition. Measurement of ethanol using HPLC and gravimetric (change in weight due to CO2 loss) methods were compared. Using the procedure developed, ethanol yields for five diverse hybrids (dent, waxy, white, high oil, and high amylose) were measured. Effects of mill type, dry solids, Tf, glucoamylase dose, and yeast addition were significant (P < 0.05). The gravimetric method estimated higher yields (428 ± 10 L/tonne) than HPLC (405 ± 15 L/tonne) and had a higher level of precision. Both methods had coefficients of variations of <4% and gave similar conclusions. In the final procedure, we used corn (25 g/batch) liquefied with α‐amylase (60 min at 90°C) in 75 mL of distilled water. Simultaneous saccharification and fermentation was used (64 hr at 32°C) with glucoamylase and yeast. Gravimetric and HPLC methods measured differences in ethanol yield for the five hybrids (158–435 L/tonne). The method is suitable for routine testing of ethanol yield potential and as a reference method for verifying more rapid measurement techniques.
A socio‐cognitive interpretation of the potential effects of downsizing on software quality performance
Authors: Ambrose Paul J. , Chiravuri Ananth 
Published: May 2009

AbstractOrganizational downsizing research indicates that downsizing does not always realize its strategic intent and may, in fact, have a detrimental impact on organizational performance. In this paper, we extend the notion that downsizing negatively impacts performance and argue that organizational downsizing can potentially be detrimental to software quality performance. Using social cognitive theory (SCT), we primarily interpret the negative impacts of downsizing on software quality performance by arguing that downsizing results in a realignment of social networks (environmental factors), thereby affecting the self‐efficacy and outcome expectations of a software professional (personal factors), which, in turn, affect software quality performance (outcome of behaviour undertaken). We synthesize relevant literature from the software quality, SCT and downsizing research streams and develop a conceptual model. Two major impacts of downsizing are hypothesized in the conceptual model. First, downsizing destroys formal and informal social networks in organizations, which, in turn, negatively impacts software developers' self‐efficacy and outcome expectations through their antecedents, with consequent negative impacts on software development process efficiency and software product quality, the two major components of software quality performance. Second, downsizing negatively affects antecedents of software development process efficiency, namely top management leadership, management infrastructure sophistication, process management efficacy and stakeholder participation with consequent negative impacts on software quality performance. This theoretically grounded discourse can help demonstrate how organizational downsizing can potentially impact software quality performance through key intervening constructs. We also discuss how downsizing and other intervening constructs can be managed to mitigate the negative impacts of downsizing on software quality performance.
Genetic analysis of aquabirnaviruses isolated from wild fish reveals occurrence of natural reassortment of infectious pancreatic necrosis virus
Authors: Romero‐Brey I , Bandín I , Cutrín J M , Vakharia V N , Dopazo C P 
Published: May 2009

AbstractIn this study, we report the sequencing of the whole genome [including the 5′ and 3′ non‐coding regions (NCR) of both segments A and B] of seven birnavirus strains isolated from wild fish from the Flemish Cap (FC) fishery at Newfoundland, Canada. From analysis and comparison of the sequences, most of the FC isolates clustered with the North American reference strains West Buxton (WB), Dry Mill and Jasper. One strain was included in the same genotype as the European strain Ab. In addition, at least in one case cohabitation of both type strains in an individual fish was demonstrated. These results clearly suggest the acquisition of the viruses from two different sources. The prevalence of the American type is easily explained by the close proximity of this fishing bank to the American coast whereas, although surprising, the presence of the European type strain could be because of migration of fish from European waters. In one strain, segment A and B sequences were typed differently (WB and Ab, respectively). These findings indicate natural reassortment between two strains of aquabirnaviruses in a host.
Microsatellite analysis of genetic diversity among clinical and nonclinical Saccharomyces cerevisiae isolates suggests heterozygote advantage in clinical environments
Authors: MULLER LUDO A. H. , McCUSKER JOHN H. 
Published: May 2009

AbstractThe genetic structure of a global sample of 170 clinical and nonclinical Saccharomyces cerevisiae isolates was analysed using 12 microsatellite markers. High levels of genetic diversity were revealed both among the clinical and among the nonclinical S. cerevisiae isolates without significant differentiation between these two groups of isolates, rendering a single origin of pathogenic isolates unlikely. This suggests that S. cerevisiae is a true opportunistic pathogen, with a diversity of unrelated genetic backgrounds able to cause infections in humans, and that the ability of S. cerevisiae isolates to cause infections is likely due to a combination of their phenotypic plasticity and the immune system status of the exposed individuals. As was previously reported for bread, beer and wine strains and for environmental S. cerevisiae isolates, the microsatellite genotypes indicated ploidy level variation, from possibly haploid up to tetraploid, among clinical S. cerevisiae isolates. However, rather than haploid, sporulation proficiency and spore viability data indicated that most S. cerevisiae isolates that were mono‐allelic at all examined microsatellite loci were likely homothallic and self‐diploidized. Interestingly, the proportion of heterozygous clinical isolates was found to be significantly higher than the proportion of heterozygous nonclinical isolates, suggesting a selective advantage of heterozygous S. cerevisiae yeasts in clinical environments.
Upper bathyal trace fossils document palaeoclimate changes
Authors: Hohenegger Johann , Pervesler Peter , Uchman Alfred , Wagreich Michael 
Published: May 2009

AbstractMarine trace fossils were investigated in a 102‐m cored section that covers −14.379 to −14.142 Ma (Middle Miocene). Long‐term climate trends are perfectly reflected by changing trace fossil communities of the upper bathyal (−200 to −300 m). The community structure is expressed in abundance of taxa based on probabilities of time concordance between the deposition of the sediment and the time, when the traces were produced. Changes in community structure precisely parallel the increasing δ13C isotopes during the Middle Miocene climate transition and perfectly mirror oscillations in solar insolation in both amplitudes and phase. Furthermore, the density stratification of the seawater caused by wind‐induced currents is reflected in trace fossil communities. Additionally, the dependence of ichnotaxa abundance from threshold values in the sedimentation rate could be demonstrated.
Consecutive national surveys of ABO‐incompatible blood transfusion in Japan
Authors: Fujii Y. , Shibata Y. , Miyata S. , Inaba S. , Asai T. , Hoshi Y. , Takamatsu J. , Takahashi K. , Ohto H. , Juji T. , Sagawa K. 
Published: May 2009

Background and Objectives  Morbidity and mortality from ABO‐incompatible transfusion persist as consequences of human error. Even so, insufficient attention has been given to improving transfusion safety within the hospital.Materials and Methods  National surveys of ABO‐incompatible blood transfusions were conducted by the Japanese Society of Blood Transfusion, with support from the Ministry of Health, Labor and Welfare. Surveys concluded in 2000 and 2005 analysed ABO‐incompatible transfusion data from the previous 5 years (January 1995 to December 1999 and January 2000 to December 2004, respectively). The first survey targeted 777 hospitals and the second, 1355 hospitals. Data were collected through anonymous questionnaires.Results  The first survey achieved a 77·4% response rate (578 of 777 hospitals). The second survey collected data from 251 more hospitals, but with a lower response rate (61·2%, or 829 of 1355 hospitals). The first survey analysed 166 incidents from 578 hospitals, vs. 60 incidents from 829 hospitals in the second survey. The main cause of ABO‐incompatible transfusion was identification error between patient and blood product: 55% (91 of 166) in the first survey and 45% (27 of 60) in the second. Patient outcomes included nine preventable deaths from 1995 to 1999, and eight preventable deaths from 2000 to 2004.Conclusion  Misidentification at the bedside persists as the main cause of ABO‐incompatible transfusion.
Robust QTL fine mapping by applying a quantitative transmission disequilibrium test to the Mendelian sampling term
Authors: Simianer H. , Pimentel E.C.G. 
Published: May 2009

SummaryIn many farm animal populations, high‐density single nucleotide polymorphism (SNP) genotypes are becoming available on a large scale, and routine estimation of breeding values is implemented for a multiplicity of traits. We propose to apply the basic principle of the quantitative transmission disequilibrium test (QTDT) to estimated Mendelian sampling terms. A two‐step procedure is suggested, where in the first step additive breeding values are estimated with a mixed linear model and the Mendelian sampling terms are calculated from the estimated breeding values. In the second step, the QTDT is applied to these estimated Mendelian sampling terms. The resulting test is expected to yield significant results if the SNP is in sufficient linkage disequilibrium and linkage with quantitative trait loci (QTL). This principle is illustrated with a simulated data set comprising 4665 individuals genotyped for 6000 SNP and 15 true QTL. Thirteen of the fifteen QTL were significant on a genome‐wide 0.1% error level. Results for the empirical power are derived from repeated samples of 1000 and 3000 genotyped individuals, respectively. General properties and potential extensions of the methodology are indicated. Owing to its computational simplicity and speed, the suggested procedure is well suited to scan whole genomes with high‐density SNP coverage in samples of substantial size and for a multiplicity of different traits.
High‐resolution seabed imagery as a tool for biodiversity conservation planning on continental margins
Authors: Schlacher Thomas A. , Williams Alan , Althaus Franziska , Schlacher‐Hoenlinger Monika A. 
Published: May 2009

AbstractSubmarine canyons increase seascape diversity on continental margins and harbour diverse and abundant biota vulnerable to fishing. Because many canyons are fished, there is an increasing emphasis on including them in conservation areas on continental margins. Here we report on sponge diversity and bottom cover in three canyons of South‐eastern Australia, test the performance of biological and abiotic surrogates, and evaluate how biological data from detailed seabed surveys can be used in conservation planning in these habitats. The biological data on sponge assemblage structure and species richness were obtained from 576 seafloor images taken between 148 and 472 m depth, yielding 65 morphospecies. Seafloor characteristics were similar within and between canyons, being almost exclusively composed of sediments with very few rocky substrates of higher relief. This environmental homogeneity did not, however, translate into biological uniformity of the megabenthos, and environmental factors were consequently poor predictors of biological features. By contrast, total bottom cover of sponges was highly correlated with species richness and served as a good proxy for species‐level data in this situation. Design strategies that employ information on cover or richness of sponges provided a large dividend in conservation effort by dramatically reducing the number of spatial units required to achieve a specified conservation target of 50–90% of species to be included in reserves. This demonstrates that image‐derived data are useful for the design of reserves in the deep sea, particularly where extractive sampling is not warranted. Using biological data on the sponge megabenthos to identify conservation units can also minimise socio‐economic costs to fisheries because of a smaller geographic and bathymetric ambit of conservation areas.