bluuebunny/crossref_metadata_2025 huggingface dataset:
Intraperitoneal Fat and Insulin Resistance in Obese Adolescents
Authors:   Glaser Pediatric Research Network Obesity Study Group
Published: August 2009

Obesity is epidemic among adolescents in the United States. We sought to analyze the anthropometric measures of adiposity and fasting indices of insulin resistance, including insulin‐like growth factor–binding protein‐1 (IGFBP‐1), and to provide a clinical estimate of intraperitoneal (IP) fat in obese adolescents (BMI ≥95th percentile), between ages 13 and 17 years. Subjects had baseline testing to determine eligibility for a subsequent randomized, placebo‐controlled trial of metformin XR therapy. Anthropometry and dual‐energy X‐ray absorptiometry (DXA) were used to quantify total body fat while abdominal computed tomography (CT) was used to measure IP (CT‐IP) and subcutaneous (CT‐SQ) fat. Using anthropometry and fasting laboratory data, we constructed regression models for both CT‐IP and CT‐SQ. A total of 92 subjects, 33 males, were evaluated. Of the 92 subjects, 19 were black. Fasting insulin concentrations were highly associated with other measures of insulin resistance. Median percent body fat across all subjects, as measured by DXA, was 41%. Using CT measures, 67% of abdominal cross‐sectional area was fat, 14% of which was IP fat. In multiple regression analysis, waist circumference (WC) and BMI, jointly and independently, were strongly associated with both CT‐IP and CT‐SQ fat. BMI and WC explained 62% of variance of CT‐SQ fat, but only 26% of variance of CT‐IP fat. Adding triglyceride:high‐density lipoprotein (TG:HDL) ratio and IGFBP‐1 (among nonblacks) to the regression model increased the explained variance for estimating CT‐IP fat to 45%. When evaluating the metabolic morbidity of an obese adolescent, a model using fasting IGFBP‐1, TG:HDL, BMI, and WC may be worthwhile as an estimate of IP fat.
Computer systems are dynamical systems
Authors: Mytkowicz Todd , Diwan Amer , Bradley Elizabeth
Published: August 2009

In this paper, we propose a nonlinear dynamics-based framework for modeling and analyzing computer systems. Working with this framework, we use a custom measurement infrastructure and delay-coordinate embedding to study the dynamics of these complex nonlinear systems. We find strong indications, from multiple corroborating methods, of low-dimensional dynamics in the performance of a simple program running on a popular Intel computer—including the first experimental evidence of chaotic dynamics in real computer hardware. We also find that the dynamics change completely when we run the same program on a different type of Intel computer, or when that program is changed slightly. This not only validates our framework; it also raises important issues about computer analysis and design. These engineered systems have grown so complex as to defy the analysis tools that are typically used by their designers: tools that assume linearity and stochasticity and essentially ignore dynamics. The ideas and methods developed by the nonlinear dynamics community, applied and interpreted in the context of the framework proposed here, are a much better way to study, understand, and design modern computer systems.
Theoretically informed coarse grain simulations of polymeric systems
Authors: Pike Darin Q. , Detcheverry François A. , Müller Marcus , de Pablo Juan J.
Published: August 2009

A Monte Carlo formalism for the study of polymeric melts is described. The model is particle-based, but the interaction is derived from a local density functional that appears in the field-based model. The method enables Monte Carlo simulations in the nVT, nPT, semigrandcanonical and Gibbs ensembles, and direct calculation of free energies. The approach is illustrated in the context of two examples. In the first, we consider the phase separation of a binary homopolymer blend and present results for the phase diagram and the critical point. In the second, we address the microphase separation of a symmetric diblock copolymer, examine the distribution of local stresses in lamellae, and determine the order-disorder transition temperature.
Experimental demonstration of surface acoustic waves in two-dimensional phononic crystals with fluid background
Authors: Jia Han , Ke Manzhu , He Zhaojian , Peng Shasha , Liu Gangqiang , Mei Xuefei , Liu Zhengyou
Published: August 2009

The surface acoustic waves of a two-dimensional phononic crystal in water are investigated experimentally. By measuring the field distribution on the surface of the phononic crystal, a surface acoustic mode is clearly demonstrated. By introducing a periodical corrugation onto the surface of the phononic crystal and by a pointlike stimulation on the surface, a collimated acoustic beam with a small divergent angle is observed, which results from the coupling of the point source to the surface modes. This experimental realization may be of significance in the applications of surface acoustic waves in phononic crystals.
Microstructures formation in a seemingly ideal homogeneous mixture of ethanol and methanol: An experimental evidence and two-dimensional correlation spectroscopy approach
Authors: Mello Cesar , Mello Thomás , Sevéri Eza , Coelho Lucinda , Ribeiro Diórginis , Marangoni Antônio , Poppi Ronei J. , Noda Isao
Published: August 2009

An anomalous solution behavior at the molecular scale was observed for macroscopically homogeneous mixtures of methanol and ethanol. Two-dimensional Raman correlation spectroscopy was used to elucidate the possible existence of microstructures formed in the mixture. The result suggests that separate methanol and ethanol clusters are formed without heterohydrogen bonding between different alcohol species. Supramolecular structures seem to be formed by the interaction of such clusters with each other through cohesion and dispersion forces, but not through direct hydrogen bonding connections.
Analytic twist angle measurement in liquid crystal cells
Authors: Lee Chang-Hun , Salter P. , Raynes E. P. , Elston S. J.
Published: August 2009

Previously we have described a method to measure residual twist angle in homogeneously aligned liquid crystal cells by comparing experimental results with simulated data in an electric field. This allows determination of a small twist angle to an accuracy of 0.02°. In this paper, an analytic method is described whereby it is possible to determine the small twist angle directly from the measured transmission without simulation. A simple equation for the twist angle independent of any material parameters is derived and its reliability and accuracy confirmed by comparison with the results of the previous method.
Delayed transiently chaotic neural networks and their application
Authors: Chen Shyan-Shiou
Published: August 2009

In this paper, we propose a novel model, a delayed transiently chaotic neural network (DTCNN), and numerically confirm that the model performs better in finding the global minimum for the traveling salesman problem (TSP) than the traditional transiently chaotic neural network. The asymptotic stability and chaotic behavior of the dynamical system with time delay are fully discussed. We not only theoretically prove the existence of Marotto’s chaos for the delayed neural network without the cooling schedule by geometrically constructing a transversal homoclinic orbit, but we also discuss the stability of nonautonomous delayed systems using LaSalle’s invariance principle. The result of the application to the TSP by the DTCNN might further explain the importance of systems with time delays in the neural system.
Selective probing of mRNA expression levels within a living cell
Authors: Nawarathna D. , Turan T. , Wickramasinghe H. Kumar
Published: August 2009

We report on a selective and nondestructive measurement of mRNA (messenger ribonucleic acid) expression levels within a living cell. We first modify an atomic force microscope tip to create a tapered nanoscale coaxial cable. Application of an ac (alternating potential) between the inner and outer electrodes of this cable creates a dielectrophoretic force attracting mRNA molecules toward the tip-end which is pretreated with gene specific primers. We selectively extracted and analyzed both high (∼2500) and extremely low (11¯0) copy number mRNA from a living cell mRNA in less than 10 s.
Martensitic transformation and magnetic field-induced strain in Fe–Mn–Ga shape memory alloy
Authors: Omori T. , Watanabe K. , Umetsu R. Y. , Kainuma R. , Ishida K.
Published: August 2009

Martensitic and magnetic properties of Fe–Mn–Ga single and polycrystalline alloys were investigated. It was found that Fe–Mn–Ga alloys exhibit martensitic transformation from the paramagnetic L21 Heusler parent phase to the ferromagnetic L10 martensite phase. The martensitic transformation temperatures increased by about 20 K by the application of a magnetic field of 7 T, and a metamagnetic phase transition was observed. In addition, a magnetic field-induced strain of 0.6% associated with magnetic field-induced forward transformation was confirmed in an Fe43Mn28Ga29 single crystal.
Experimental study of microwave radiation of carbon nanotube arrays
Authors: Zhu Qi , Liu Weifeng , Zhang Hualiang , Xin Hao
Published: August 2009

Microwave radiation effects of carbon nanotube (CNT) arrays are investigated experimentally by placing them on the surface of microstrip patch antennas. The radiation intensities of different patch antenna configurations with and without CNT arrays are measured and compared. The experimental results indicate that the addition of CNT arrays significantly enhances the electromagnetic radiation of the antenna.
Efficient picosecond optical parametric oscillator based on periodically poled lithium tantalate
Authors: Bhupathiraju Kalyan V. , Rowley Joseph D. , Ganikhanov Feruz
Published: August 2009

Generation of transform limited picosecond pulses continuously tunable across wavelengths in the near-infrared (995–1340 nm) and midinfrared (2.1–3.6 μm) range is demonstrated in an optical parametric oscillator (OPO) based on a periodically poled stoichiometric lithium tantalate crystal. The OPO, which is synchronously pumped by a mode-locked Ti:sapphire laser, delivers about 1 W in combined average power at a repetition rate of 74 MHz, which represents close to 45% extraction efficiency in output power. With wavelength and bandwidth controlled via an intracavity diffraction grating, about 2.7 ps pulses with 3.8–10.9 cm−1 bandwidth (full width at half maximum) were generated across the tuning range in the near-infrared thus making the OPO an optimal source for use in various nonlinear spectroscopy and microscopy applications that require high spectral resolution.
Cascaded exciton emission of an individual strain-induced quantum dot
Authors: Schülein F. J. R. , Laucht A. , Riikonen J. , Mattila M. , Sopanen M. , Lipsanen H. , Finley J. J. , Wixforth A. , Krenner H. J.
Published: August 2009

Single strain-induced quantum dots are isolated for optical experiments by selective removal of the inducing InP islands from the sample surface. Unpolarized emission of single exciton, biexciton, and triexciton transitions are identified by power-dependent photoluminescence spectroscopy. Employing time-resolved experiments performed at different excitation powers, we find a pronounced shift of the rise and decay times of these different transitions as expected from cascaded single photon emissions. Good agreement is found for a rate equation model for a three step cascade.
Between-country collaboration and consideration of costs increase conservation planning efficiency in the Mediterranean Basin
Authors: Kark Salit , Levin Noam , Grantham Hedley S. , Possingham Hugh P.
Published: August 2009

The importance of global and regional coordination in conservation is growing, although currently, the majority of conservation programs are applied at national and subnational scales. Nevertheless, multinational programs incur transaction costs and resources beyond what is required in national programs. Given the need to maximize returns on investment within limited conservation budgets, it is crucial to quantify how much more biodiversity can be protected by coordinating multinational conservation efforts when resources are fungible. Previous studies that compared different scales of conservation decision-making mostly ignored spatial variability in biodiversity threats and the cost of actions. Here, we developed a simple integrating metric, taking into account both the cost of conservation and threats to biodiversity. We examined the Mediterranean Basin biodiversity hotspot, which encompasses over 20 countries. We discovered that for vertebrates to achieve similar conservation benefits, one would need substantially more money and area if each country were to act independently as compared to fully coordinated action across the Basin. A fully coordinated conservation plan is expected to save approximately US$67 billion, 45% of total cost, compared with the uncoordinated plan; and if implemented over a 10-year period, the plan would cost ≈0.1% of the gross national income of all European Union (EU) countries annually. The initiative declared in the recent Paris Summit for the Mediterranean provides a political basis for such complex coordination. Surprisingly, because many conservation priority areas selected are located in EU countries, a partly coordinated solution incorporating only EU-Mediterranean countries is almost as efficient as the fully coordinated scenario.
Human genetic deficiencies reveal the roles of complement in the inflammatory network: Lessons from nature
Authors: Lappegård Knut Tore , Christiansen Dorte , Pharo Anne , Thorgersen Ebbe Billmann , Hellerud Bernt Christian , Lindstad Julie , Nielsen Erik Waage , Bergseth Grethe , Fadnes Dag , Abrahamsen Tore G. , Høiby E. Arne , Schejbel Lone , Garred Peter , Lambris John D. , Harboe Morten , Mollnes Tom Eirik
Published: August 2009

Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to Gram-negative bacteria were here studied taking advantage of human genetic complement-deficiencies—nature's own knockouts—including a previously undescribed C5 defect. Such deficiencies provide a unique tool for investigating the biological role of proteins. The experimental conditions allowed cross-talk between the different inflammatory pathways using a whole blood model based on the anticoagulant lepirudin, which does not interfere with the complement system. Expression of tissue factor, cell adhesion molecules, and oxidative burst depended highly on C5, mediated through the activation product C5a, whereas granulocyte enzyme release relied mainly on C3 and was C5a-independent. Release of cytokines and chemokines was mediated to varying degrees by complement and CD14; for example, interleukin (IL)-1β and IL-8 were more dependent on complement than IFN-γ and IL-6, which were highly dependent on CD14. IL-1 receptor antagonist (IL-1ra) and IFN-γ inducible protein 10 (IP-10) were fully dependent on CD14 and inversely regulated by complement, that is, complement deficiency and complement inhibition enhanced their release. Granulocyte responses were mainly complement-dependent, whereas monocyte responses were more dependent on CD14. Notably, all responses were abolished by combined neutralization of complement and CD14. The present study provides important insight into the comprehensive role of complement in human inflammatory responses to Gram-negative bacteria.
Mechanism by which the lectin actinohivin blocks HIV infection of target cells
Authors: Tanaka Haruo , Chiba Harumi , Inokoshi Junji , Kuno Atsushi , Sugai Takahiro , Takahashi Atsushi , Ito Yukishige , Tsunoda Masaru , Suzuki Kaoru , Takénaka Akio , Sekiguchi Takeshi , Umeyama Hideaki , Hirabayashi Jun , Ōmura Satoshi
Published: August 2009

Various lectins have attracted attention as potential microbicides to prevent HIV transmission. Their capacity to bind glycoproteins has been suggested as a means to block HIV binding and entry into susceptible cells. The previously undescribed lectin actinohivin (AH), isolated by us from an actinomycete, exhibits potent in vitro anti-HIV activity by binding to high-mannose (Man) type glycans (HMTGs) of gp120, an envelope glycoprotein of HIV. AH contains 114 aa and consists of three segments, all of which need to show high affinity to gp120 for the anti-HIV characteristic. To generate the needed mechanistic understanding of AH binding to HIV in anticipation of seeking approval for human testing as a microbicide, we have used multiple molecular tools to characterize it. AH showed a weak affinity to Manα(1–2)Man, Manα(1–2)Manα(1–2)Man, of HMTG (Man8 or Man9) or RNase B (which has a single HMTG), but exhibited a strong and highly specific affinity (Kd= 3.4 × 10−8M) to gp120 of HIV, which contains multiple Man8 and/or Man9 units. We have compared AH to an alternative lectin, cyanovirin-N, which did not display similar levels of discrimination between high- and low-density HMTGs. X-ray crystal analysis of AH revealed a 3D structure containing three sugar-binding pockets. Thus, the strong specific affinity of AH to gp120 is considered to be due to multivalent interaction of the three sugar-binding pockets with three HMTGs of gp120 via the “cluster effect” of lectin. Thus, AH is a good candidate for investigation as a safe microbicide to help prevent HIV transmission.
Probing PML body function in ALT cells reveals spatiotemporal requirements for telomere recombination
Authors: Draskovic Irena , Arnoult Nausica , Steiner Villier , Bacchetti Silvia , Lomonte Patrick , Londoño-Vallejo Arturo
Published: August 2009

Promyelocytic leukemia (PML) bodies (also called ND10) are dynamic nuclear structures implicated in a wide variety of cellular processes. ALT-associated PML bodies (APBs) are specialized PML bodies found exclusively in telomerase-negative tumors in which telomeres are maintained by recombination-based alternative (ALT) mechanisms. Although it has been suggested that APBs are directly implicated in telomere metabolism of ALT cells, their precise role and structure have remained elusive. Here we show that PML bodies in ALT cells associate with chromosome ends forming small, spatially well-defined clusters, containing on average 2–5 telomeres. Using an innovative approach that gently enlarges PML bodies in living cells while retaining their overall organization, we show that this physical enlargement of APBs spatially resolves the single telomeres in the cluster, but does not perturb the potential of the APB to recruit chromosome extremities. We show that telomere clustering in PML bodies is cell-cycle regulated and that unique telomeres within a cluster associate with recombination proteins. Enlargement of APBs induced the accumulation of telomere-telomere recombination intermediates visible on metaphase spreads and connecting heterologous chromosomes. The strand composition of these recombination intermediates indicated that this recombination is constrained to a narrow time window in the cell cycle following replication. These data provide strong evidence that PML bodies are not only a marker for ALT cells but play a direct role in telomere recombination, both by bringing together chromosome ends and by promoting telomere-telomere interactions between heterologous chromosomes.
5 Years of Experience Implementing a Methicillin-Resistant Staphylococcus aureus Search and Destroy Policy at the Largest University Medical Center in the Netherlands
Authors: Vos Margreet C. , Behrendt Myra D. , Melles Damian C. , Mollema Femke P. N. , de Groot Woutrinus , Parlevliet Gerard , Ott Alewijn , Horst-Kreft Deborah , van Belkum Alex , Verbrugh Henri A.
Published: August 2009

Objective.

TO evaluate the effectiveness of a rigorous search and destroy policy for controlling methicillin-resistant Staphylococcus aureus (MRSA) infection or colonization.

Design.

Hospital-based observational follow-up study.

Setting.

Erasmus University Medical Center Rotterdam, a 1,200-bed tertiary care center in Rotterdam, the Netherlands.

Methods.

Outbreak control was accomplished by the use of active surveillance cultures for persons at risk, by the preemptive isolation of patients at risk, and by the strict isolation of known MRSA carriers and the eradication of MRSA carriage. For unexpected cases of MRSA colonization or infection, patients placed in strict isolation or contact isolation and healthcare workers (HCWs) were screened. We collected data from 2000–2004.

Results.

During the 5-year study period, 51,907 MRSA screening cultures were performed for 21,598 persons at risk (8,403 patients and 13,195 HCWs). By screening, it was determined that 123 (1.5%) of 8,403 patients and 31 (0.2%) of 13,195 HCWs were MRSA carriers. From the performance of clinical cultures, it was determined that 54 additional patients were MRSA carriers, resulting in a total of 177 patients carrying MRSA. Of the 177 patients carrying MRSA, 144 (81%) were primary patients, and 33 (19%) secondary Patients. The average number of nosocomial transmissions was 6.7 per year. The cumulative incidence of MRSA colonization among this group of patients was 0.10 cases per 100 admissions. Of 156 cases of MRSA colonization, 44 (28%) were acquired in a foreign healthcare institution, and 45 (29%) were acquired in other Dutch hospitals, 22 (47%) of which were acquired in a single hospital in our region. There were 16 cases (10%) that occurred in a nursing home and another 16 cases (10%) that fulfilled our definition of community-acquired MRSA colonization; there were 4 cases (3%) categorized as “other” and 31 cases (20%) for which the source of MRSA acquisition remained unknown. The basic reproduction rate was 10-fold less for patients isolated on admission, compared with those who were not. During the 5-year study period, 5 episodes of MRSA bacteremia occurred in which 4 patients died, an incidence rate of 0.28 cases of infection per 100,000 patient-days per year.

Conclusion.

Our results show that, during a rigorous search and destroy policy, a low incidence of MRSA in our medical center was continuously observed and that this policy most likely contributed to a very low nosocomial transmission rate.
Impact of an Antimicrobial Utilization Program on Antimicrobial Use at a Large Teaching Hospital A Randomized Controlled Trial
Authors: Camins Bernard C. , King Mark D. , Wells Jane B. , Googe Heidi L. , Patel Manish , Kourbatova Ekaterina V. , Blumberg Henry M.
Published: August 2009

Background.

Multidisciplinary antimicrobial utilization teams (AUTs) have been proposed as a mechanism for improving antimicrobial use, but data on their efficacy remain limited.

Objective.

To determine the impact of an AUT on antimicrobial use at a teaching hospital.

Design.

Randomized controlled intervention trial.

Setting.

A 953-bed, public, university-affiliated, urban teaching hospital.

Patients.

Patients who were given selected antimicrobial agents (piperacillin-tazobactam, levofloxacin, or vancomycin) by internal medicine ward teams.

Intervention.

Twelve internal medicine teams were randomly assigned monthly: 6 teams to an intervention group (academic detailing by the AUT) and 6 teams to a control group that was given indication-based guidelines for prescription of broad-spectrum antimicrobials (standard of care), during a 10-month study period.

Measurements.

Proportion of appropriate empirical, definitive (therapeutic), and end (overall) antimicrobial usage.

Results.

A total of 784 new prescriptions of piperacillin-tazobactam, levofloxacin, and vancomycin were reviewed. The proportion of antimicrobial prescriptions written by the intervention teams that was considered to be appropriate was significantly higher than the proportion of antimicrobial prescriptions written by the control teams that was considered to be appropriate: 82% versus 73% for empirical (risk ratio [RR], 1.14; 95% confidence interval [CI], 1.04-1.24), 82% versus 43% for definitive (RR, 1.89; 95% CI, 1.53-2.33), and 94% versus 70% for end antimicrobial usage (RR, 1.34; 95% CI, 1.25-1.43). In multivariate analysis, teams that received feedback from the AUT alone (adjusted RR, 1.37; 95% CI, 1.27-1.48) or from both the AUT and the infectious diseases consultation service (adjusted RR, 2.28; 95% CI, 1.64-3.19) were significantiy more likely to prescribe end antimicrobial usage appropriately, compared with control teams.

Conclusions.

A multidisciplinary AUT that provides feedback to prescribing physicians was an effective method in improving antimicrobial use.

Trial Registration.

ClinicalTrials.gov identifier: NCT00552838.
Normal Hopf subalgebras of semisimple Hopf algebras
Authors: Burciu Sebastian
Published: August 2009

The notion of kernel of a representation of a semisimple Hopf algebra is introduced. Similar properties to those of the kernel of a group representation are proved in some special cases. In particular, every normal Hopf subalgebra of a semisimple Hopf algebra

H
H

is the kernel of a representation of

H
H

. The maximal normal Hopf subalgebras of

H
H

are described.
Ehrhart theory for Lawrence polytopes and orbifold cohomology of hypertoric varieties
Authors: Stapledon Alan
Published: August 2009

We establish a connection between the orbifold cohomology of hypertoric varieties and the Ehrhart theory of Lawrence polytopes. More specifically, we show that the dimensions of the orbifold cohomology groups of a hypertoric variety are equal to the coefficients of the Ehrhartδ\delta-polynomial of the associated Lawrence polytope. As a consequence, we deduce a formula for the Ehrhartδ\delta-polynomial of a Lawrence polytope and use the injective part of the Hard Lefschetz Theorem for hypertoric varieties to deduce some inequalities between the coefficients of theδ\delta-polynomial.
Every graph has an embedding in 𝑆³ containing no non-hyperbolic knot
Authors: Flapan Erica , Howards Hugh
Published: August 2009

In contrast with knots, whose properties depend only on their extrinsic topology in

S
3

S^3

, there is a rich interplay between the intrinsic structure of a graph and the extrinsic topology of all embeddings of the graph in

S
3

S^3

. For example, it was shown by Conway and Gordon that every embedding of the complete graph

K
7

K_7

in

S
3

S^3

contains a non-trivial knot. Later it was shown that for every

m
∈
N

m\in N

there is a complete graph

K
n

K_n

such that every embedding of

K
n

K_n

in

S
3

S_3

contains a knot

Q
Q

whose minimal crossing number is at least

m
m

. Thus there are arbitrarily complicated knots in every embedding of a sufficiently large complete graph in

S
3

S^3

. We prove the contrasting result that every graph has an embedding in

S
3

S^3

such that every non-trivial knot in that embedding is hyperbolic. Our theorem implies that every graph has an embedding in

S
3

S^3

which contains no composite or satellite knots.
Arithmetic progressions in abundance by combinatorial tools
Authors: Beiglböck Mathias
Published: August 2009

Using the algebraic structure of the Stone-Čech compactification of the integers, Furstenberg and Glasner proved that for arbitrary

k
∈

N

k\in \mathbb {N}

, every piecewise syndetic set contains a piecewise syndetic set of

k
k

-term arithmetic progressions.

We present a purely combinatorial argument which allows us to derive this result directly from van der Waerden’s Theorem.
The reverse ultra log-concavity of the Boros-Moll polynomials
Authors: Chen William , Gu Cindy
Published: August 2009

We prove the reverse ultra log-concavity of the Boros-Moll polynomials. We further establish an inequality which implies the log-concavity of the sequence

{
i
!

d
i

(
m
)
}

\{i!d_i(m)\}

for any

m
≥
2

m\geq 2

, where

d
i

(
m
)

d_i(m)

are the coefficients of the Boros-Moll polynomials

P
m

(
a
)

P_m(a)

. This inequality also leads to the fact that in the asymptotic sense, the Boros-Moll sequences are just on the borderline between ultra log-concavity and reverse ultra log-concavity. We propose two conjectures on the log-concavity and reverse ultra log-concavity of the sequence

{

d

i
−
1

(
m
)

d

i
+
1

(
m
)

/

d
i

(
m

)
2

}

\{d_{i-1}(m) d_{i+1}(m)/d_i(m)^2\}

for

m
≥
2

m\geq 2

.
Carleson measures for Bergman spaces and their dual Berezin transforms
Authors: Choe Boo , Koo Hyungwoon , Stessin Michael
Published: August 2009

We introduce the notion of weighted dual Berezin transforms and characterize Carleson measures for weighted Bergman spaces over the ball by a certain BMO property of their dual Berezin transforms.
Isolated singularities for the exponential type semilinear elliptic equation in ℝ²
Authors: Dhanya R. , Giacomoni J. , Prashanth S.
Published: August 2009

In this article we study positive solutions of the equation−Δu=f(u)-\Delta u= f(u)in a punctured domainΩ′=Ω∖{0}\Omega ’=\Omega \setminus \{0\}inR2\mathbb {R}^2and show sharp conditions on the nonlinearityf(t)f(t)that enables us to extend such a solution to the whole domainΩ\Omegaand also preserve its regularity. We also show, using the framework of bifurcation theory, the existence of at least two solutions for certain classes of exponential type nonlinearities.
Jordan gradings on exceptional simple Lie algebras
Authors: Elduque Alberto
Published: August 2009

Models of all the gradings on the exceptional simple Lie algebras induced by Jordan subgroups of their groups of automorphisms are provided.
Hopf quivers and Nichols algebras in positive characteristic
Authors: Cibils Claude , Lauve Aaron , Witherspoon Sarah
Published: August 2009

We apply a combinatorial formula of the first author and Rosso for products in Hopf quiver algebras to determine the structure of Nichols algebras. We illustrate this technique by explicitly constructing new examples of Nichols algebras in positive characteristic. We further describe the corresponding Radford biproducts and some liftings of these biproducts, which are new finite-dimensional pointed Hopf algebras.
Burghelea-Haller analytic torsion for manifolds with boundary
Authors: Su Guangxiang
Published: August 2009

In this paper, we extend the complex-valued Ray-Singer torsion, introduced by Burghelea-Haller, to compact connected Riemannian manifolds with boundary. We also compare it with the refined analytic torsion.
Noncommutative 𝐿_{𝑝}-space and operator system
Authors: Han Kyung
Published: August 2009

We show that noncommutative

L
p

L_p

-spaces satisfy the axioms of the (nonunital) operator system with a dominating constant

2

1
p

2^{1 \over p}

. Therefore, noncommutative

L
p

L_p

-spaces can be embedded into

B
(
H
)

B(H)

2

1
p

2^{1 \over p}

-completely isomorphically and complete order isomorphically.
Point count divisibility for algebraic sets over ℤ/𝕡^{ℓ}ℤ and other finite principal rings
Authors: Katz Daniel
Published: August 2009

We determine the greatest common divisor of the cardinalities of the algebraic sets generated by collections of polynomialsf1,…,ftf_1,\ldots ,f_tof specified degreesd1,…,dtd_1,\ldots ,d_tinnnvariables over a finite principal ringRR. This generalizes the theorems of Ax (t=1t=1,RRa field), N. M. Katz (ttarbitrary,RRa field), and Marshall-Ramage (t=1t=1,RRan arbitrary finite principal ring).
Density of mild mixing property for vertical flows of Abelian differentials
Authors: Frączek Krzysztof
Published: August 2009

We prove that if

g
≥
2

g\geq 2

, then the set of all Abelian differentials

(
M
,
ω
)

(M,\omega )

for which the vertical flow is mildly mixing is dense in every stratum of the moduli space

H

g

\mathcal {H}_g

. The proof is based on a sufficient condition due to Frączek, Lemańczyk, and Lesigne guaranteeing mild mixing property of certain special flows over irrational rotations.
Almost commuting unitaries with spectral gap are near commuting unitaries
Authors: Osborne Tobias
Published: August 2009

Let

M

n

\mathcal {M}_n

be the collection of

n
×
n

n\times n

complex matrices equipped with operator norm. Suppose

U
,
V
∈

M

n

U, V \in \mathcal {M}_n

are two unitary matrices, each possessing a gap larger than

Δ
\Delta

in their spectrum, which satisfy

‖
U
V
−
V
U
‖
≤
ϵ

\|UV-VU\| \le \epsilon

. Then it is shown that there are two unitary operators

X
X

and

Y
Y

satisfying

X
Y
−
Y
X
=
0

XY-YX = 0

and
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-vertical-bar upper U minus upper X double-vertical-bar plus double-vertical-bar upper V minus upper Y double-vertical-bar less-than-or-equal-to upper E left-parenthesis normal upper Delta squared slash epsilon right-parenthesis left-parenthesis StartFraction epsilon Over normal upper Delta squared EndFraction right-parenthesis Superscript one sixth">

‖
U
−
X
‖
+
‖
V
−
Y
‖
≤
E
(

Δ
2

/

ϵ
)

(

ϵ

Δ
2

)

1
6

\|U-X\| + \|V-Y\| \le E(\Delta ^2/\epsilon ) \left (\frac {\epsilon }{\Delta ^2}\right )^{\frac 16}

, where

E
(
x
)

E(x)

is a function growing slower than

x

1
k

x^{\frac {1}{k}}

for any positive integer

k
k

.
On the solvability of vector fields with real linear coefficients
Authors: Treves François
Published: August 2009

The following result is proved: for a vector field with real linear coefficients to be locally solvable in

R

n

\mathbb {R}^{n}

it is necessary and sufficient that not all its orbits have a compact closure in the complement of the critical set of the vector field.
Lois du logarithme itéré avec pondérations additives
Authors: Tenenbaum Gérald
Published: August 2009

We provide a very short proof that natural Lindeberg type conditions on the non-negative arithmetic additive function

f
f

ensure the strong law of large numbers and the law of the iterated logarithm for weighted sums

∑

n
⩽
N

f
(
n
)

X
n

\sum _{n\leqslant N}f(n)X_n

for any sequence

{

X
n

}

n
=
1

∞

\{X_n\}_{n=1}^\infty

of i.i.d. random variables.
A wavelet characterization for the dual of weighted Hardy spaces
Authors: Lee Ming-Yi , Lin Chin-Cheng , Lin Ying-Chieh
Published: August 2009

We define the weighted Carleson measure space

C
M

O
w
p

CMO^p_w

using wavelets, where the weight function

w
w

belongs to the Muckenhoupt class. Then we show that

C
M

O
w
p

CMO^p_w

is the dual space of the weighted Hardy space

H
w
p

H^p_w

by using sequence spaces. As an application, we give a wavelet characterization of

B
M

O
w

BMO_w

.
A uniform estimate for Fourier restriction to simple curves
Authors: Oberlin Daniel
Published: August 2009

We prove a uniform Fourier extension-restriction estimate for a certain class of curves in

R

d

\mathbb {R}^d

.
Stability in 𝐿¹ of circular vortex patches
Authors: Sideris Thomas , Vega Luis
Published: August 2009

The motion of incompressible and ideal fluids is studied in the plane. The stability in

L
1

L^1

of circular vortex patches is established among the class of all bounded vortex patches of equal strength.
Knockdown of theDrosophilaGTPase Nucleostemin 1 Impairs Large Ribosomal Subunit Biogenesis, Cell Growth, and Midgut Precursor Cell Maintenance
Authors: Rosby Raphyel , Cui Zhengfang , Rogers Emily , deLivron Megan A. , Robinson Victoria L. , DiMario Patrick J.
Published: August 2009

Mammalian nucleostemin (NS) is a nucleolar guanosine triphosphate-binding protein implicated in cell cycle progression, stem cell proliferation, and ribosome assembly. Drosophila melanogaster contains a four-member nucleostemin family (NS1–4). NS1 is the closest orthologue to human NS; it shares 33% identity and 67% similarity with human NS. We show that NS1 has intrinsic GTPase and ATPase activity and that it is present within nucleoli of most larval and adult cells. Endogenous NS1 and lightly expressed green fluorescent protein (GFP)-NS1 enrich within the nucleolar granular regions as expected, whereas overexpressed GFP-NS1 localized throughout the nucleolus and nucleoplasm, and to several transcriptionally active interbands of polytene chromosomes. Severe overexpression correlated with the appearance of melanotic tumors and larval/pupal lethality. Depletion of 60% of NS1 transcripts also lead to larval and pupal lethality. NS1 protein depletion>95 correlated with the loss of imaginal island (precursor) cells in the larval midgut and to an apparent block in the nucleolar release of large ribosomal subunits in terminally differentiated larval midgut polyploid cells. Ultrastructural examination of larval Malpighian tubule cells depleted for NS1 showed a loss of cytoplasmic ribosomes and a concomitant appearance of cytoplasmic preautophagosomes and lysosomes. We interpret the appearance of these structures as indicators of cell stress response.
Dual Functions of Mss51 Couple Synthesis of Cox1 to Assembly of CytochromecOxidase inSaccharomyces cerevisiaeMitochondria
Authors: Perez-Martinez Xochitl , Butler Christine A. , Shingu-Vazquez Miguel , Fox Thomas D.
Published: August 2009

Functional interactions of the translational activator Mss51 with both the mitochondrially encoded COX1 mRNA 5′-untranslated region and with newly synthesized unassembled Cox1 protein suggest that it has a key role in coupling Cox1 synthesis with assembly of cytochrome c oxidase. Mss51 is present at levels that are near rate limiting for expression of a reporter gene inserted at COX1 in mitochondrial DNA, and a substantial fraction of Mss51 is associated with Cox1 protein in assembly intermediates. Thus, sequestration of Mss51 in assembly intermediates could limit Cox1 synthesis in wild type, and account for the reduced Cox1 synthesis caused by most yeast mutations that block assembly. Mss51 does not stably interact with newly synthesized Cox1 in a mutant lacking Cox14, suggesting that the failure of nuclear cox14 mutants to decrease Cox1 synthesis, despite their inability to assemble cytochrome c oxidase, is due to a failure to sequester Mss51. The physical interaction between Mss51 and Cox14 is dependent upon Cox1 synthesis, indicating dynamic assembly of early cytochrome c oxidase intermediates nucleated by Cox1. Regulation of COX1 mRNA translation by Mss51 seems to be an example of a homeostatic mechanism in which a positive effector of gene expression interacts with the product it regulates in a posttranslational assembly process.
The effect of local dominance and reciprocal tolerance on feeding aggregations of ocellated antbirds
Authors: Chaves-Campos Johel , Araya-Ajoy Yi-men , Lizana-Moreno Claudia A. , Rabenold Kerry N.
Published: August 2009

We studied ocellated antbirds (Phaenostictus mcleannani) to test the hypothesis that reciprocal tolerance between dominant individuals can favour feeding in aggregations. Mated pairs hold large non-exclusive feeding ranges, but roost and nest in a small portion of this range (‘roosting area’); adjacent roosting neighbours are unrelated. Ocellated antbirds congregate to feed on arthropods fleeing from nomadic swarms of army ants that move across the ranges of many pairs. We used playback experiments to simulate acoustic challenges, and results showed that males responded aggressively to other males only in their roosting areas. Responses to adjacent neighbours were less aggressive than to non-neighbours (i.e. the ‘dear enemy’ effect). Prey intake rates were higher when birds fed in their own roosting area or in that of adjacent neighbours compared with more distant sites. Males tolerated adjacent neighbours at swarm fronts where prey are most dense, but more distant neighbours were displaced. Despite small samples for some analyses, our results suggest that reciprocal tolerance between adjacent unrelated neighbours can ameliorate intraspecific competition within ephemeral feeding aggregations.
Competition promotes the evolution of host generalists in obligate parasites
Authors: Johnson Kevin P. , Malenke Jael R. , Clayton Dale H.
Published: August 2009

Ecological theory traditionally predicts that interspecific competition selects for an increase in ecological specialization. Specialization, in turn, is often thought to be an evolutionary ‘dead end,’ with specialist lineages unlikely to evolve into generalist lineages. In host–parasite systems, this specialization can take the form of host specificity, with more specialized parasites using fewer hosts. We tested the hypothesis that specialists are evolutionarily more derived, and whether competition favours specialization, using the ectoparasitic feather lice of doves. Phylogenetic analyses revealed that complete host specificity is actually the ancestral condition, with generalists repeatedly evolving from specialist ancestors. These multiple origins of generalists are correlated with the presence of potentially competing species of the same genus. A competition experiment with captive doves and lice confirmed that congeneric species of lice do, in fact, have the potential to compete in ecological time. Taken together, these results suggest that interspecific competition can favour the evolution of host generalists, not specialists, over macroevolutionary time.
Presence of a conspecific causes divergent changes in resting metabolism, depending on its relative size
Authors: Millidine K. J. , Metcalfe N. B. , Armstrong J. D.
Published: August 2009

It is well established that the average metabolism of many species of fish varies with group size. However, it is not clear whether all individuals respond in the same way. Here, we use a newly calibrated method of measuring the metabolic rate of fish from opercular (ventilatory) movements that allows for the first-time estimation of changes in resting metabolic rate (RMR) of each individual within different social groups and when alone. The presence of a conspecific had divergent effects on the RMR of juvenile Atlantic salmonSalmo salar, depending on its relative body size: the presence of a smaller fish caused a 40 per cent reduction, whereas the presence of a slightly larger fish approximately doubled RMR. These effects occurred in the absence of activity and were sustained at lower magnitude in the case of the relatively smaller conspecific even if a transparent barrier prevented any physical interactions between fish. Changes in RMR were mirrored by changes in eye colour that indicate they were linked to stress levels. These contrasting and strong responses show that even the nearby presence of a conspecific can have profound and variable effects on an individual's energy budget; they also highlight the complex trade-offs involved in social interactions.
Sperm competitiveness in frogs: slow and steady wins the race
Authors: Dziminski Martin A. , Roberts J. Dale , Beveridge Maxine , Simmons Leigh W.
Published: August 2009

When sperm compete to fertilize available ova, selection is expected to favour ejaculate traits that contribute to a male's fertilization success. While there is much evidence to show that selection favours increased numbers of sperm, only a handful of empirical studies have examined how variation in sperm form and function contributes to competitive fertilization success. Here, we examine selection acting on sperm form and function in the externally fertilizing myobatrachid frog,Crinia georgiana. Usingin vitrofertilization techniques and controlling for variation in the number of sperm contributed by males in competitive situations, we show that males with a greater proportion of motile sperm, and motile sperm with slower swimming velocities, have an advantage when competing for fertilizations. Sperm morphology and the degree of genetic similarity between putative sires and the female had no influence on competitive fertilization success. These unusual patterns of selection might explain why frog sperm typically exhibit relatively slow swimming speeds and sustained longevity.
An Allelic Mutant Series of ATM3 Reveals Its Key Role in the Biogenesis of Cytosolic Iron-Sulfur Proteins in Arabidopsis
Authors: Bernard Delphine G. , Cheng Youfa , Zhao Yunde , Balk Janneke
Published: August 2009

The ATP-binding cassette transporters of mitochondria (ATMs) are highly conserved proteins, but their function in plants is poorly defined. Arabidopsis (Arabidopsis thaliana) has three ATM genes, namely ATM1, ATM2, and ATM3. Using a collection of insertional mutants, we show that only ATM3 has an important function for plant growth. Additional atm3 alleles were identified among sirtinol-resistant lines, correlating with decreased activities of aldehyde oxidases, cytosolic enzymes that convert sirtinol into an auxin analog, and depend on iron-sulfur (Fe-S) and molybdenum cofactor (Moco) as prosthetic groups. In the sirtinol-resistant atm3-3 allele, the highly conserved arginine-612 is replaced by a lysine residue, the negative effect of which could be mimicked in the yeast Atm1p ortholog. Arabidopsis atm3 mutants displayed defects in root growth, chlorophyll content, and seedling establishment. Analyses of selected metal enzymes showed that the activity of cytosolic aconitase (Fe-S) was strongly decreased across the range of atm3 alleles, whereas mitochondrial and plastid Fe-S enzymes were unaffected. Nitrate reductase activity (Moco, heme) was decreased by 50% in the strong atm3 alleles, but catalase activity (heme) was similar to that of the wild type. Strikingly, in contrast to mutants in the yeast and mammalian orthologs, Arabidopsis atm3 mutants did not display a dramatic iron homeostasis defect and did not accumulate iron in mitochondria. Our data suggest that Arabidopsis ATM3 may transport (1) at least two distinct compounds or (2) a single compound required for both Fe-S and Moco assembly machineries in the cytosol, but not iron.
A WD40 Repeat Protein fromMedicago truncatulaIs Necessary for Tissue-Specific Anthocyanin and Proanthocyanidin Biosynthesis But Not for Trichome Development
Authors: Pang Yongzhen , Wenger Jonathan P. , Saathoff Katie , Peel Gregory J. , Wen Jiangqi , Huhman David , Allen Stacy N. , Tang Yuhong , Cheng Xiaofei , Tadege Million , Ratet Pascal , Mysore Kirankumar S. , Sumner Lloyd W. , Marks M. David , Dixon Richard A.
Published: August 2009

WD40 repeat proteins regulate biosynthesis of anthocyanins, proanthocyanidins (PAs), and mucilage in the seed and the development of trichomes and root hairs. We have cloned and characterized a WD40 repeat protein gene from Medicago truncatula (MtWD40-1) via a retrotransposon-tagging approach. Deficiency of MtWD40-1 expression blocks accumulation of mucilage and a range of phenolic compounds, including PAs, epicatechin, other flavonoids, and benzoic acids, in the seed, reduces epicatechin levels without corresponding effects on other flavonoids in flowers, reduces isoflavone levels in roots, but does not impair trichome or root hair development. MtWD40-1 is expressed constitutively, with highest expression in the seed coat, where its transcript profile temporally parallels those of PA biosynthetic genes. Transcript profile analysis revealed that many genes of flavonoid biosynthesis were down-regulated in a tissue-specific manner in M. truncatula lines harboring retrotransposon insertions in the MtWD40-1 gene. MtWD40-1 complemented the anthocyanin, PA, and trichome phenotypes of the Arabidopsis (Arabidopsis thaliana) transparent testa glabrous1 mutant. We discuss the function of MtWD40-1 in natural product formation in M. truncatula and the potential use of the gene for engineering PAs in the forage legume alfalfa (Medicago sativa).