bluuebunny/crossref_metadata_2025 huggingface dataset:
The undulatory motion of a chain of particles in a resistive medium in the case of a smooth excitation mode
Authors: Bolotnik N. , Pivovarov M. , Zeidis I. , Zimmermann K.
Published: June 2013

The motion of a chain of three identical bodies along a straight line in a dry‐friction medium is studied. The motion is excited and controlled by changing the distances between the bodies of the chain. An undulatory excitation mode is proposed, in which the distances between the adjacent bodies of the chain change periodically and the time histories of the distances in the pairs of adjacent bodies consecutively repeat each other with a constant time shift. It looks like a wave is running along the chain. The necessary and sufficient conditions for the system to be able to move from rest are established. For a specific excitation mode, in which the time histories of the distances between the bodies of the chain are defined as piecewise quadratic functions, a steady‐state motion of the system is studied for the case where the friction force is small in comparison with the force necessary for a body of the chain to be moved from a state of rest through a distance characterizing the amplitude of oscillations of adjacent bodies during the excitation period.
On localized modes of free vibrations of single‐walled carbon nanotubes embedded in nonhomogeneous elastic medium
Authors: Mikhasev G.
Published: June 2013

Free axisymmetric vibrations of a single‐walled carbon nanotube (SWCNT) embedded in a nonhomogeneous elastic matrix are studied on the base of the nonlocal continuum shell theory. The effect of the surrounding elastic medium are considered using the Winkler‐type spring constant which is assumed to be variable along the tube axis. The tube may be prestressed by external tensile forces. The Flügge type shell equations, including the initial membrane hoop and axial stresses, are used as the governing ones. The constitutive equations are formulated by considering the small‐scale effects. Using the asymptotic approach, the SWCNT eigenmodes are constructed in the form of functions decreasing rapidly away from some “weakest” line which is assumed to be far from the tube edges. This study shows that introducing the small length scale parameter into the tube model allows to take into account inclusions in the surrounding elastic matrix which may results in the strong localization of some eigenmodes. The dependence of the natural frequencies and the power of the localization of the corresponding modes upon the constant of non‐locality, tensile stresses and the nanotube radius is analyzed.
Dimension reduction for models of pollutant transport with sedimentation
Authors: Limić N. , Starčević M.
Published: June 2013

In this paper we present a model for transport of substance with sedimentation governed by a water flow in a shallow basin. The model is developed by using a dimension reduction technique in an infinite layer. The concentration of substance is modeled by a 2D‐approximation, corrected in the vertical direction. In applications 2D‐models are often used in shallow basins as it was illustrated for instance in [Legović T., Limić N., Valković V., Estuar. Coast. Shelf Sci. 30, 619–654, (1990)]. Here we establish the acceptability criterion for the reduction, based on the mass conservation law. Thus we discuss the existence of solutions to the original 3D‐model and the deduced 2D‐model with L1 source terms. For the conclusion we prove that the relative error of sedimentation rates for the original and deduced model tends to zero as the distance from the source of substance tends to infinity.
Small‐amplitude grain boundaries of arbitrary angle in the Swift‐Hohenberg equation
Authors: Scheel A. , Wu Q.
Published: June 2013

We study grain boundaries in the Swift‐Hohenberg equation. Grain boundaries arise as stationary interfaces between roll solutions of different orientations. Our analysis shows that such stationary interfaces exist near onset of instability for arbitrary angles between the roll solutions. This extends prior work in [6] where the analysis was restricted to large angles, that is, weak bending near the grain boundary. The main new difficulty stems from possible interactions of the primary modes with other resonant modes. We generalize the normal form analysis in [6] and develop a singular perturbation approach to treat resonances.
Application of fractional order theory of thermoelasticity to a 1D problem for a half‐space
Authors: Sherief H.H. , Abd El‐Latief A.M.
Published: June 2013

In this work, we apply the fractional order theory of thermoelasticity to a 1D thermal shock problem for a half‐space. Laplace transform techniques are used. The predictions of the theory are discussed and compared with those for the coupled and generalized theories of thermoelasticity. Numerical results are computed and represented graphically for the temperature, displacement and stress distributions.
On uniqueness results for an elliptic‐parabolic‐system of partial differential equations arising in dynamic electrowetting
Authors: Fontelos M.A. , Grün G.
Published: June 2013

We prove regularity results and, as a consequence, uniqueness for a system of partial differential equations arising in the study of dynamic electrowetting phenomena and more general electrokinetic processes in three space dimensions. The system consists of Stokes equations coupled with equations for the motion of electric charges, Poisson equation for computing the electric field generated by such charges and a Cahn‐Hilliard equation for a phase field describing two fluids with different material parameters. The deduction and existence of weak solutions for this system was established in an earlier paper (Christof Eck et al., On a phase‐field model for electrowetting, Interfaces Free Bound. 11 (2), 259–290, (2009)).
Stress concentration in an anisotropic body with three equal collinear cracks in Mode II of fracture. I. Analytical study
Authors: Craciun E.M. , Sadowski T. , Răbâea A.
Published: June 2013

One consider an anisotropic, unbounded elastic body containing three collinear, equal cracks subjected to asymmetrically tangential stresses, case corresponding to Mode II of classical Fracture. We determine the elastic state produced in the body using the formalism of Riemann‐Hilbert problem and the representation of elastic stresses and displacements fields due to Lekhnitskii. Using the asymptotical analysis, we obtain the asymptotic values of the stress and the displacement fields in a vicinity of the cracks tips.
Effects of nitrogen addition on litter decomposition, soil microbial biomass, and enzyme activities between leguminous and non‐leguminous forests
Authors: Lv Yanna , Wang Congyan , Wang Fangyuan , Zhao Guiying , Pu Gaozhong , Ma Xu , Tian Xingjun
Published: June 2013

Anthropogenic nitrogen (N) deposition is an expanding problem that affects the functioning and composition of forest ecosystems, particularly the decomposition of forest litters. Legumes play an important role in the nitrogen cycle of forest ecosystems. Two litter types were chosen from Zijin Mountain in China: Robinia pseudoacacia leaves from a leguminous forest (LF) and Liquidambar formosana leaves from a non‐leguminous forest (NF). The litter samples were mixed into original forest soils and incubated in microcosms. Then, they were treated by five forms of N addition: NH4+, NO3−, urea, glycine, and a mixture of all four. During a 6‐month incubation period, litter mass losses, soil microbial biomass, soil pH, and enzyme activities were investigated. Results showed that mixed N and NO3−‐N addition significantly accelerated the litter decomposition rates of LF leaves, while mixed N, glycine‐N, and urea‐N addition significantly accelerated the litter decomposition rates of NF leaves. Litter decomposition rates and soil enzyme activities under mixed N addition were higher than those under single form of N additions in the two forest types. Nitrogen addition had no significant effects on soil pH and soil microbial biomass. The results indicate that nitrogen addition may alter microbial allocation to extracellular enzyme production without affecting soil microbial biomass, and then affected litter decomposition process. The results further reveal that mixed N is a more important factor in controlling litter decomposition process than single form of N, and may seriously affect soil N cycle and the release of carbon stored belowground.
An Exploratory Study of Aggression in School-Age Children: Underlying Factors and Implications for Treatment
Authors: Priddis Lynn E. , Landy Sarah , Moroney Darren , Kane Robert
Published: June 2013

Aggressive behaviour in school-aged children presents a significant challenge for society. If not managed, it can result in adverse academic, social, emotional, and behavioural outcomes for the child. In addition, it can create stress for families and become a significant burden for the community as these children reach adolescence and adulthood, and engage in antisocial behaviours. Using a three-step exploratory analytical strategy, this study explored parent and child reports of a diverse range of underlying developmental and clinical variables that have been identified in the literature as predictors of aggressive child behaviour, and which could be addressed within an Australian school or community context. A total of 57 children and their parents were recruited from a referral-based Western Australian child mental health service, and the wider community. A group of 31 clinically aggressive children were identified and compared to a group of 26 non-aggressive children. The aggressive group was reported as having a greater prevalence of internalising symptoms, including anxiety and depression, and their aggressive behaviour was more likely to be of the callous/unemotional type, relative to their non-aggressive counterparts. Significant predictors of belonging to the aggressive group included child social problems, thought problems, attention problems, affective problems, narcissism, symptoms of ADHD and PTS, and low maternal self-esteem. Findings are presented and discussed in the context of established theories. Recommendations for principles of treatment for aggressive children and their families are suggested.
Putting the CEFR to good use: Designing grammars based on learner-corpus evidence
Authors: McCarthy Michael
Published: June 2013

This lecture considers what reference and pedagogical grammars and grammar teaching materials for L2 learners should ideally include, based on corpus evidence from both native-speaker and learner corpora. I demonstrate how learner corpora can be used to track the emergence of grammatical features, from the elementary level to advanced, how learners get to grips with new grammar and what we can learn from the statistical output of error-coded corpora. Additionally, we look at how the divide between lexis and grammar becomes progressively blurred and how corpus information can best be used to produce useful grammars and teaching materials for students at different levels. The advanced level in particular is focused on. The lecture is presented within the framework of the English Profile Project (EPP), a large, international, inter-disciplinary project which uses corpora to investigate learner competence at different levels of the Common European Framework of Reference (CEFR).
Motivations impacting upon music instrument teachers’ decisions to teach and perform in higher education
Authors: Parkes Kelly A. , Daniel Ryan
Published: June 2013

The purpose of this study was to explore why highly trained musicians choose to teach in higher education. An international population from nine countries of music instrument teachers was sampled via online survey, to determine their reasons for teaching in higher education. Motivational constructs from the expectancy-value framework were used, and data were analysed statistically and qualitatively for themes. Findings show that participants held significantly higher expectancy beliefs about teaching than performing, and significantly higher intrinsic interest value beliefs about performing than about teaching. All six constructs were positively correlated with cost for music performing and teaching predicting the most variance.
COST-EFFECTIVENESS OF AN INTERVENTION TO REDUCE FEAR OF FALLING
Authors: van Haastregt Jolanda C. M. , Zijlstra G.A. Rixt , Hendriks Marike R. C. , Goossens Mariëlle E.J.B. , van Eijk Jacques Th.M. , Kempen Gertrudis I.J.M.
Published: June 2013

Objectives:The aim of this study was to assess whether a multicomponent cognitive behavioral group intervention is preferable to usual care in terms of (healthcare) costs and effects on fear of falling and activity avoidance.

Methods:This economic evaluation was embedded in a randomized controlled trial among 540 community-living adults in the Netherlands, aged 70 years and older who reported fear of falling and fear-induced activity avoidance. The participants allocated to the intervention group received a multicomponent cognitive behavioral group intervention consisting of eight weekly sessions and a booster session. The sessions were aimed at instilling realistic views of falls, reducing fall risk, and increasing activity and safe behavior. Participants in the control group received usual care. Cost outcome measures were healthcare costs, and patient and family costs. Clinical outcomes were fear of falling and activity avoidance. All outcomes were assessed at baseline and at 2, 8, and 14 months by means of registration forms, self-administered questionnaires, and interviews by telephone.

Results:Participants were randomly allocated to intervention (n= 280) and control groups (n= 260). Costs for the intervention program were on average €276 per person. Total costs per person were comparable (€4,925 in intervention group and €4,828 in control group). Furthermore, favorable effects of the program were observed for fear of falling and activity avoidance.

Conclusions:This study showed that the intervention program is preferable to usual care in terms of costs and effects. The program had comparable costs and significantly reduced fear of falling and associated activity avoidance among older community-living persons.
UNESCO and the Fate of the World Heritage Indigenous Peoples Council of Experts (WHIPCOE)
Authors: Meskell Lynn
Published: June 2013

In December 2000, a World Indigenous Peoples Forum was held in conjunction with the 24th session of UNESCO's World Heritage Committee in Cairns, Australia. Representatives from Australia, Canada, and New Zealand harnessed the momentum of these events and their location to propose the formation of a new committee, the World Heritage Indigenous Peoples Council of Experts (WHIPCOE). The initiative was taken in response to concerns voiced by indigenous peoples to their lack of involvement in the development and implementation of laws, policies, and plans for the protection of their knowledge, traditions, and cultural values, which apply to their ancestral lands, within or comprising sites now designated as World Heritage properties. This article traces the fate of that proposal and underlines the intransigence of sovereign states during those short-lived discussions. It goes on to suggest alternate routes for indigenous representation and recognition within the World Heritage system.
Geschlechterstereotype auf Führungsebene zwischen 1974 und 2010
Authors: Hartl Barbara , Kirchler Erich , Muehlbacher Stephan
Published: June 2013

Frauen sind selten in Führungspositionen vertreten. Eine Erklärung dafür könnte in Rollenkonflikten liegen, die aus den vorherrschenden Stereotypen über Frauen und über Führungskräfte entstehen. Die vorliegende Arbeit untersucht Veränderungen der Stereotype über weibliche und über männliche Führungskräfte in einem Zeitraum von 36 Jahren. Dazu wurde eine Inhaltsanalyse von Todesanzeigen aus vier deutschsprachigen Zeitungen durchgeführt. Es zeigte sich, dass über die Zeit vor allem die Beschreibung der weiblichen Führungskräfte variiert, während die Darstellung verstorbener Männer in Führungspositionen vergleichsweise stabil ist. Eine tendenzielle Annährung der Geschlechterstereotype scheint aber stattzufinden. Den Führungsstil betreffend konnten keine statistisch bedeutsamen Geschlechtsunterschiede hinsichtlich Aufgabenorientierung und lediglich 2004 ein signifikanter Geschlechtsunterschied in der Zuschreibung von Personenorientierung der verstorbenen Führungskräfte festgestellt werden. Männliche Führungskräfte wurden aber zu den sehr frühen als auch zu den sehr späten Beobachtungszeitpunkten häufiger mit erfolgskorrelierten und stabilen Eigenschaften beschrieben als Frauen.
Mechanisms of Enhanced Basal Tone of Brain Parenchymal Arterioles During Early Postischemic Reperfusion: Role of ET-1-Induced Peroxynitrite Generation
Authors: Cipolla Marilyn J , Sweet Julie G , Gokina Natalia I , White Sheryl L , Nelson Mark T
Published: June 2013

The contributions of vasoconstrictors (endothelin-1 (ET-1), peroxynitrite) and endothelium-dependent vasodilatory mechanisms to basal tone were investigated in parenchymal arterioles (PAs) after early postischemic reperfusion. Transient middle cerebral artery occlusion (tMCAO) was induced for 2 hours with 30 minutes reperfusion in male Wistar rats and compared with ischemia alone (permanent MCAO (pMCAO);2.5 hours) or sham controls. Changes in lumen diameter of isolated and pressurized PAs were compared. Quantitative PCR was used to measure endothelin type B (ETB) receptors. Constriction to intravascular pressure (‘basal tone’) was not affected by tMCAO or pMCAO. However, constriction to inhibitors of endothelial cell, small-(SK) and intermediate-(IK) conductance, Ca2+-sensitive K+ channels (apamin and TRAM-34, respectively) were significantly enhanced in PAs from tMCAO compared with pMCAO or sham. Addition of the ETB agonist sarafotoxin caused constriction in PAs from tMCAO but not from sham animals (21±4% versus 3±3% at 1 nmol/L; P<0.01) that was inhibited by the peroxynitrite scavenger FeTMPyP (5,10,15,20-tetrakis (N-methyl-4′-pyridyl) porphinato iron (III) chloride) (100 μmol/L). Expression of ETB receptors was not found on PA smooth muscle, suggesting that constriction to sarafotoxin after tMCAO was due to peroxynitrite and not ETB receptor expression. The maintenance of basal tone in PAs after tMCAO may restrict flow to the ischemic region and contribute to infarct expansion.
Quantum decoherence of I2 in liquid xenon: A classical Wigner approach
Authors: Elran Yossi , Brumer Paul
Published: June 2013

Vibrational decoherence of a “breathing sphere” oscillator in a thermal Lennard-Jones bath is examined using a classical analog approach. The equivalence between this approach and the linearized semiclassical initial value representation (IVR) is established and the method is exploited to produce a useful computational strategy that can efficiently evaluate the time dependence of the decoherence in these systems. A comparison between Harmonic and Morse “breathing sphere” models is presented and the rate of decoherence is found to depend on the choice of model, the initial state of the oscillator, the initial conditions of the bath (temperature, density), and the choice of quantity measuring the decoherence rate. The results are used to examine the utility of the Caldeira-Leggett model in this realistic system.
Systematic study of interface trap and barrier inhomogeneities using I-V-T characteristics of Au/ZnO nanorods Schottky diode
Authors: Hussain I. , Soomro M. Y. , Bano N. , Nur O. , Willander M.
Published: June 2013

This paper presents in-depth analysis of I-V-T characteristics of Au/ZnO nanorods Schottky diodes. The temperature dependence I-V parameters such as the ideality factor and the barrier heights have been explained on the basis of inhomogeneity. Detailed and systematic analysis was performed to extract information about the interface trap states. The ideality factor decreases, while the barrier height increases with increase of temperature. These observations have been ascribed to barrier inhomogeneities at the Au/ZnO nanorods interface. The inhomogeneities can be described by the Gaussian distribution of barrier heights. The effect of tunneling, Fermi level pinning, and image force lowering has contribution in the barrier height lowering. The recombination-tunneling mechanism is used to explain the conduction process in Au/ZnO nanorods Schottky diodes. The ionization of interface states has been considered for explaining the inhomogeneities.
Littrow angle based autocollimation method for precision online monitoring three-dimensional angular drifts of chirped-pulse compression-gratings
Authors: Li Zhaoyang , Wang Tao , Xu Guang , Li Dawei , Chen Lei , Dai Yaping
Published: June 2013

A simple optical method for online precisely monitoring three-dimensional (3D) angular drifts of chirped-pulse compression-gratings in chirped-pulse amplification (CPA) lasers is proposed. Monitoring objects include all dimensional angular drifts of a grating, especially the grating groove in-plane-rotation. Monitoring contents contain direction and amount. And monitoring results are obtained by detecting the direction and the amount of 2D relative offsets of three focal spots formed by a ternary monitoring beam line. The theoretical model of the proposed method is set up using a matrix ray-tracing method, and a simplified monitoring equation is concluded based on numerical simulations. And the validity of this method is verified by a simple demonstration experiment. Besides, monitoring error and reliability discussion of the method are presented, as well.
Isotropic and anisotropic wrinkling of diamond-like carbon films on polydimethylsiloxane substrates
Authors: Teixeira F. S. , Salvadori M. C. , Araújo W. W. R. , Amorim H. J. M. , Cattani M. , Brown I. G.
Published: June 2013

We describe experimental results about the spontaneous wrinkling of diamond-like carbon films over the thickness range 2 nm–58 nm, grown on polydimethylsiloxane (PDMS) substrates with a 5 nm gold film deposited as adhesion layer. Using Atomic Force Microscopy data with suitable processing, we explore both isotropic and anisotropic wrinkling, the latter done by creating trench structures on PDMS substrates. We show new non-predictable results based on the known literature.
Ga-doped ZnO conducting antireflection coatings for crystalline silicon solar cells
Authors: Estrich N. A. , Hook D. H. , Smith A. N. , Leonard J. T. , Laughlin B. , Maria J.-P.
Published: June 2013

Transparent, conductive gallium-doped ZnO thin films are evaluated for application as conducting antireflection coatings (ARC) for crystalline silicon solar cells as a means to enhance efficiency by reducing the overall resistivity of the photovoltaic circuit. All Ga-doped ZnO thin films in this study were deposited using pulsed laser deposition. Synthesis conditions were first optimized for maximum electrical resistivity and minimal visible light absorption. The ideal combination contained 1 mol. % Ga doping and exhibited ∼90% transmission, with resistivity in the 1 × 10−3 ohm-cm range. Optimized films were prepared on reference flat silicon wafers with known dopant densities and on commercially obtained solar cell emitters without ARCs. Circular transmission line method measurements were used to measure specific contact resistivity (ρc). For n-type doped solar cell emitters, contact resistivity values of 0.1 mΩ cm2 were observed repeatedly. These values are consistent with, or lower than, contact resistivities associated with conventional silver paste metallization.
Quantum confinement in two dimensional layers of PbSe/ZnSe multiple quantum well structures
Authors: Arivazhagan V. , Manonmani Parvathi M. , Rajesh S. , Sæterli Ragnhild , Holmestad Randi
Published: June 2013

The structural and optical properties of thermally evaporated PbSe/ZnSe multiple quantum well (MQW) structures as a function of the PbSe quantum well (QW) layer thickness in the range between 2.5 and 10 nm have been investigated. An ordered periodicity in the MQW structure was confirmed by transmission electron microscopy. The discrete linear resonances in the absorption spectra and the corresponding blue shift observed with decreasing well layer thickness unambiguously reflect the quantum confinement effect. The effective QW band gap is calculated from the infinite well approximation and compared to the experimentally observed value. The QW emission is identified and discussed.
Modelling of secondary organic aerosol formation from isoprene photooxidation chamber studies using different approaches
Authors: Zhang Haofei , Parikh Harshal M. , Bapat Jyoti , Lin Ying-Hsuan , Surratt Jason D. , Kamens Richard M.
Published: June 2013

Environmental context
Fine particulate matter (PM2.5) in the Earth’s atmosphere plays an important role in climate change and human health, in which secondary organic aerosol (SOA) that forms from the photooxidation of volatile organic compounds (VOCs) has a significant contribution. SOA derived from isoprene, the most abundant non-methane VOC emitted into the Earth’s atmosphere, has been widely studied to interpret its formation mechanisms. However, the ability to predict isoprene SOA using current models remains difficult due to the lack of understanding of isoprene chemistry.

Abstract
Secondary organic aerosol (SOA) formation from the photooxidation of isoprene was simulated against smog chamber experiments with varied concentrations of isoprene, nitrogen oxides (NOx=NO + NO2) and ammonium sulfate seed aerosols. A semi-condensed gas-phase isoprene chemical mechanism (ISO-UNC) was coupled with different aerosol-phase modelling frameworks to simulate SOA formation, including: (1) the Odum two-product approach, (2) the 1-D volatility basis-set (VBS) approach and (3) a new condensed kinetic model based upon the gas-particle partitioning theory and reactive uptake processes. The first two approaches are based upon empirical parameterisations from previous studies. The kinetic model uses a gas-phase mechanism to explicitly predict the major intermediate precursors, namely the isoprene-derived epoxides, and hence simulate SOA formation. In general, they all tend to significantly over predict SOA formation when semivolatile concentrations are higher because more semivolatiles are forced to produce SOA in the models to maintain gas-particle equilibrium; yet the data indicate otherwise. Consequently, modified dynamic parameterised models, assuming non-equilibrium partitioning, were incorporated and could improve the model performance. In addition, the condensed kinetic model was expanded by including an uptake limitation representation so that reactive uptake processes slow down or even stop; this assumes reactive uptake reactions saturate seed aerosols. The results from this study suggest that isoprene SOA formation by reactive uptake of gas-phase precursors is likely limited by certain particle-phase features, and at high gas-phase epoxide levels, gas-particle equilibrium is not obtained. The real cause of the limitation needs further investigation; however, the modified kinetic model in this study could tentatively be incorporated in large-scale SOA models given its predictive ability.
Molecular mechanisms of multiple toxin–antitoxin systems are coordinated to govern the persister phenotype
Authors: Fasani Rick A. , Savageau Michael A.
Published: June 2013

Significance

Persisters are drug-tolerant bacteria that account for the majority of bacterial infections. They are not mutants, but rather slowly growing cells in a heterogeneous population. Evidence links them to the toxin–antitoxin systems present in nearly all bacteria. To explore the connection, we have created a system-level model of toxin–antitoxin systems that includes molecular mechanisms, stochastic fluctuations, variable growth rate, and population dynamics. The results quantitatively describe how a noisy environment can give rise to a bet-hedging subpopulation of persisters that always exists, not just in reaction to stress. Furthermore, multiple toxin–antitoxin systems can cooperate to increase the persister frequency.
Evolutionary changes of multiple visual pigment genes in the complete genome of Pacific bluefin tuna
Authors: Nakamura Yoji , Mori Kazuki , Saitoh Kenji , Oshima Kenshiro , Mekuchi Miyuki , Sugaya Takuma , Shigenobu Yuya , Ojima Nobuhiko , Muta Shigeru , Fujiwara Atushi , Yasuike Motoshige , Oohara Ichiro , Hirakawa Hideki , Chowdhury Vishwajit Sur , Kobayashi Takanori , Nakajima Kazuhiro , Sano Motohiko , Wada Tokio , Tashiro Kosuke , Ikeo Kazuho , Hattori Masahira , Kuhara Satoru , Gojobori Takashi , Inouye Kiyoshi
Published: June 2013

Tunas are migratory fishes in offshore habitats and top predators with unique features. Despite their ecological importance and high market values, the open-ocean lifestyle of tuna, in which effective sensing systems such as color vision are required for capture of prey, has been poorly understood. To elucidate the genetic and evolutionary basis of optic adaptation of tuna, we determined the genome sequence of the Pacific bluefin tuna (
Thunnus orientalis
), using next-generation sequencing technology. A total of 26,433 protein-coding genes were predicted from 16,802 assembled scaffolds. From these, we identified five common fish visual pigment genes: red-sensitive (middle/long-wavelength sensitive; M/LWS), UV-sensitive (short-wavelength sensitive 1; SWS1), blue-sensitive (SWS2), rhodopsin (RH1), and green-sensitive (RH2) opsin genes. Sequence comparison revealed that tuna's RH1 gene has an amino acid substitution that causes a short-wave shift in the absorption spectrum (i.e., blue shift). Pacific bluefin tuna has at least five RH2 paralogs, the most among studied fishes; four of the proteins encoded may be tuned to blue light at the amino acid level. Moreover, phylogenetic analysis suggested that gene conversions have occurred in each of the SWS2 and RH2 loci in a short period. Thus, Pacific bluefin tuna has undergone evolutionary changes in three genes (RH1, RH2, and SWS2), which may have contributed to detecting blue-green contrast and measuring the distance to prey in the blue-pelagic ocean. These findings provide basic information on behavioral traits of predatory fish and, thereby, could help to improve the technology to culture such fish in captivity for resource management.
Retrieval Dynamics in Self-Terminated Memory Search
Authors: Hussey Erika K. , Dougherty Michael R. , Harbison J. Isaiah , Davelaar Eddy J.
Published: June 2013

Most free-recall experiments employ a paradigm in which participants are given a preset amount of time to retrieve items from a list. While much has been learned using this paradigm, it ignores an important component of many real-world retrieval tasks: the decision to terminate memory search. The present study examines the temporal characteristics underlying memory search by comparing within subjects a standard retrieval paradigm with a finite, preset amount of time (closed interval) to a design that allows participants to terminate memory search on their own (open interval). Calling on the results of several presented simulations, we anticipated that the threshold for number of retrieval failures varied as a function of the nature of the recall paradigm, such that open intervals should result in lower thresholds than closed intervals. Moreover, this effect was expected to manifest in interretrieval times (IRTs). Although retrieval-interval type did not significantly impact the number of items recalled or error rates, IRTs were sensitive to the manipulation. Specifically, the final IRTs in the closed-interval paradigm were longer than those of the open-interval paradigm. This pattern suggests that providing participants with a preset retrieval interval not only masks an important component of the retrieval process (the memory search termination decision), but also alters temporal retrieval dynamics. Task demands may compel people to strategically control aspects of their retrieval by implementing different stopping rules.
Algebrability, non-linear properties, and special functions
Authors: Bartoszewicz Artur , Gła̧b Szymon , Pellegrino Daniel , Seoane-Sepúlveda Juan
Published: June 2013

We construct uncountably generated algebras inside the following sets of special functions: (i) Sierpiński-Zygmund functions, (ii) perfectly everywhere surjective functions, (iii) nowhere continuous Darboux functions. All conclusions obtained in this paper are improvements of some already known results.
A simple scaling for the minimum instability time-scale of two widely spaced planets
Authors: Veras Dimitri , Mustill Alexander J.
Published: June 2013

Long-term instability in multiplanet exosystems is a crucial consideration when confirming putative candidates, analysing exoplanet populations, constraining the age of exosystems and identifying the sources of white dwarf pollution. Two planets that are Hill stable are separated by a wide-enough distance to ensure that they will never collide. However, Hill-stable planetary systems may eventually manifest Lagrange instability when the outer planet escapes or the inner planet collides with the star. We show empirically that for two nearly coplanar Hill-stable planets with eccentricities less than about 0.3, instability can manifest itself only after a time corresponding to x initial orbits of the inner planet, where log10x ∼ 5.2[μ/(MJupiter/Mȯ)]−0.18 and μ is the planet–star mass ratio. This relation applies to any type of equal-mass secondaries, and suggests that two low-eccentricity Hill-stable terrestrial-mass or smaller mass planets should be Lagrange stable throughout the main-sequence lifetime of any white dwarf progenitor. However, Hill-stable giant planets are not guaranteed to be Lagrange stable, particularly within a few tens of per cent beyond the critical Hill separation. Our scaling represents a useful ‘rule of thumb’ for planetary population syntheses or individual systems for which performing detailed long-term integrations is unfeasible.
Validating Estimates of Latent Traits from Textual Data Using Human Judgment as a Benchmark
Authors: Lowe Will , Benoit Kenneth
Published: June 2013

Automated and statistical methods for estimating latent political traits and classes from textual data hold great promise, because virtually every political act involves the production of text. Statistical models of natural language features, however, are heavily laden with unrealistic assumptions about the process that generates these data, including the stochastic process of text generation, the functional link between political variables and observed text, and the nature of the variables (and dimensions) on which observed text should be conditioned. While acknowledging statistical models of latent traits to be “wrong,” political scientists nonetheless treat their results as sufficiently valid to be useful. In this article, we address the issue of substantive validity in the face of potential model failure, in the context of unsupervised scaling methods of latent traits. We critically examine one popular parametric measurement model of latent traits for text and then compare its results to systematic human judgments of the texts as a benchmark for validity.
Muscle ERRγ mitigates Duchenne muscular dystrophy via metabolic and angiogenic reprogramming
Authors: Matsakas Antonios , Yadav Vikas , Lorca Sabina , Narkar Vihang
Published: June 2013

Treatment of Duchenne muscular dystrophy (DMD) by replacing mutant dystrophin or restoring dystrophin‐associated glycoprotein complex (DAG) has been clinically challenging. Instead, identifying and targeting muscle pathways deregulated in DMD will provide new therapeutic avenues. We report that the expression of nuclear receptor estrogen‐related receptor‐γ (ERRγ), and its metabolic and angiogenic targets are downregulated (50–85%) in skeletal muscles of mdx mice (DMD model) vs. wild‐type mice. Corelatively, oxidative myofibers, muscle vasculature, and exercise tolerance (33%) are decreased in mdx vs. wild‐type mice. Overexpressing ERRγ selectively in the dystrophic muscles of the mdx mice restored metabolic and angiogenic gene expression compared with control mdx mice. Further, ERRγ enhanced muscle oxidative myofibers, vasculature, and blood flow (by 33–66%) and improved exercise tolerance (by 75%) in the dystrophic mice. Restoring muscle ERRγ pathway ameliorated muscle damage and also prevented DMD hallmarks of postexercise muscle damage, hypoxia, and fatigue in mdx mice. Notably, ERRγ did not restore sarcolemmal DAG complex, which is thus dispensable for antidystrophic effects of ERRγ. In summary, ERRγ‐dependent metabolic and angiogenic gene program is defective in DMD, and we demonstrate that its restoration is a potential strategy for treating muscular dystrophy.—Matsakas, A., Yadav, V., Lorca, S., Narkar, V., Muscle ERRγ mitigates Duchenne muscular dystrophy via metabolic and angiogenic reprogramming. FASEB J. 27, 4004–4016 (2013). www.fasebj.org
Spontaneous male death and monogyny in the dark fishing spider
Authors: Schwartz Steven K. , Wagner William E. , Hebets Eileen A.
Published: June 2013

Monogyny (male monogamy) is found in a diverse assemblage of taxa, and recent theoretical work reveals that a male-biased sex ratio can favour the evolution of this relatively rare mating system. We integrate this theoretical framework with field observations and laboratory experiments involving the sexually size dimorphic fishing spider,
Dolomedes tenebrosus
, to test the prediction that this species exhibits monogyny. Field surveys revealed a male-biased sex ratio, likely resulting from different life-history strategies (early male maturation). Results from mating trials supported our prediction of monogyny as we discovered that males mate with a single female. Unexpectedly, however, we observed that mating results in obligate male death and genital mutilation. Additional field observations of released individuals suggest that males are not limited by their ability to encounter additional females. Controlled laboratory assays demonstrated that males discriminate among virgin and non-virgin female silk cues, consistent with predictions of first-male sperm precedence. In summary, we report a novel case of male self-sacrifice in a species that exhibits female-biased sexual size dimorphism, male-biased sex ratio, genital mutilation and a suggestion of first-male sperm precedence; all of which are consistent with theoretical predictions of the evolution of monogyny.
The structure of latherin, a surfactant allergen protein from horse sweat and saliva
Authors: Vance Steven J. , McDonald Rhona E. , Cooper Alan , Smith Brian O. , Kennedy Malcolm W.
Published: June 2013

Latherin is a highly surface-active allergen protein found in the sweat and saliva of horses and other equids. Its surfactant activity is intrinsic to the protein in its native form, and is manifest without associated lipids or glycosylation. Latherin probably functions as a wetting agent in evaporative cooling in horses, but it may also assist in mastication of fibrous food as well as inhibition of microbial biofilms. It is a member of the PLUNC family of proteins abundant in the oral cavity and saliva of mammals, one of which has also been shown to be a surfactant and capable of disrupting microbial biofilms. How these proteins work as surfactants while remaining soluble and cell membrane-compatible is not known. Nor have their structures previously been reported. We have used protein nuclear magnetic resonance spectroscopy to determine the conformation and dynamics of latherin in aqueous solution. The protein is a monomer in solution with a slightly curved cylindrical structure exhibiting a ‘super-roll’ motif comprising a four-stranded anti-parallel β-sheet and two opposing α-helices which twist along the long axis of the cylinder. One end of the molecule has prominent, flexible loops that contain a number of apolar amino acid side chains. This, together with previous biophysical observations, leads us to a plausible mechanism for surfactant activity in which the molecule is first localized to the non-polar interface via these loops, and then unfolds and flattens to expose its hydrophobic interior to the air or non-polar surface. Intrinsically surface-active proteins are relatively rare in nature, and this is the first structure of such a protein from mammals to be reported. Both its conformation and proposed method of action are different from other, non-mammalian surfactant proteins investigated so far.
Acoustic propagation in non-uniform waveguides: revisiting Webster equation using evanescent boundary modes
Authors: Mercier Jean-François , Maurel Agnès
Published: June 2013

The scattering of an acoustic wave propagating in a non-uniform waveguide is inspected by revisiting improved multimodal methods in which the introduction of additional modes, so-called boundary modes, allows to better satisfy the Neumann boundary conditions at the varying walls. In this paper, we show that the additional modes can be identified as evanescent modes. Although non-physical, these modes are able to tackle the evanescent part of the field omitted by the truncation and are able to restore the right boundary condition at the walls. In the low-frequency regime, the system can be solved analytically, and the solution for an incident plane wave including one or two boundary modes is shown to be an improvement of the usual Webster equation.
Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity
Authors: Brown C. , Burslem D. F. R. P. , Illian J. B. , Bao L. , Brockelman W. , Cao M. , Chang L. W. , Dattaraja H. S. , Davies S. , Gunatilleke C. V. S. , Gunatilleke I. A. U. N. , Huang J. , Kassim A. R. , LaFrankie J. V. , Lian J. , Lin L. , Ma K. , Mi X. , Nathalang A. , Noor S. , Ong P. , Sukumar R. , Su S. H. , Sun I. F. , Suresh H. S. , Tan S. , Thompson J. , Uriarte M. , Valencia R. , Yap S. L. , Ye W. , Law R.
Published: June 2013

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.
Efficient mitigation of founder effects during the establishment of a leading-edge oak population
Authors: Hampe Arndt , Pemonge Marie-Hélène , Petit Rémy J.
Published: June 2013

Numerous plant species are shifting their range polewards in response to ongoing climate change. Range shifts typically involve the repeated establishment and growth of leading-edge populations well ahead of the main species range. How these populations recover from founder events and associated diversity loss remains poorly understood. To help fill this gap, we exhaustively investigated a newly established population of holm oak (
Quercus ilex
) growing more than 30 km ahead of the nearest larger stands. Pedigree reconstructions showed that plants belong to two non-overlapping generations and that the whole population originates from only two founder trees. The four first-generation trees that have reached maturity showed disparate mating patterns despite being full-sibs. Long-distance pollen immigration was notable despite the strong isolation of the stand: 6 per cent gene flow events in acorns collected on the trees (
n
= 255), and as much as 27 per cent among their established offspring (
n
= 33). Our results show that isolated leading-edge populations of wind-pollinated forest trees can rapidly restore their genetic diversity through the interacting effects of efficient long-distance pollen flow and purging of inbred individuals during recruitment. They imply that range expansions of these species are primarily constrained by initial propagule arrival rather than by subsequent gene flow.
Beyond the Global City Concept and the Myth of ‘Command and Control’
Authors: Smith Richard G.
Published: June 2013

The article argues that the lack of convincing empirical evidence for the global economy as being subject to ‘command and control’ results from that contention being a neo‐Marxist myth. First, imagining the global economy as being subject to ‘highly concentrated command’ through the function of some major cities as ‘strategic sites’ for the production of ‘command and control’ is traced back through several neo‐Marxist authors to narrate its genesis, and to argue that the lack of evidence for that proposition is a consequence of those antecedents envisioning capitalism as a totalizing structure, thus making the assumption that it is subject to control and coordination from a distance. Second, Taylor's interlocking world city network model is forensically examined to explain that it is fallacious because it is a structuralism that, bedevilled by a sorites paradox, contains the further problem of containing no credible evidence for the existence of ‘command centres’. Finally, the article moves beyond neo‐Marxism's key concepts by juxtaposing their assumptions with ethnographic results from social studies of finance, a manoeuvre which forges an understanding of cities as socio‐technical assemblages and eventful multiplicities, beyond, inter alia, the baseless assumption that the global economy is subject to ‘command and control’.
Dr Thomas Beddoes and the Politics of the Imagination
Authors: FAIRCLOUGH MARY
Published: June 2013

Coleridge's account of the imagination in Biographia Literaria as a phenomenon that functions to ‘idealize and to unify’ is still highly influential. But Coleridge's contemporaries explored alternative accounts of the phenomenon. For Thomas Beddoes the imagination was a vital stimulus of scientific enquiry and political activism. Beddoes's work demonstrates the extent to which the Romantic literary imagination was informed by investigations in other fields. This essay analyses Beddoes's exploration of the imagination in his scientific, political and medical practice. Beddoes's writings emphasise the importance of imaginative enquiry across all his works, and challenge the regulative effects of disciplinary distinctions.
Rebuilding Communities after Disasters: Lessons from the Tsunami Disaster in Sri Lanka
Authors: Mulligan Martin
Published: June 2013

Disaster management literature is inundated with rhetoric about ‘community participation’ or ‘community‐led recovery’, yet the studies on how to achieve this have been unconvincing, displaying a shallow understanding of what ‘community’ means. Development scholars often argue that better preparation for ‘extreme events’ can prevent them from becoming ‘disasters’, but a string of recent disasters – from Haiti to Japan – reminds us that the world community will continue to be called on to help rebuild shattered communities. This article reflects the findings of a major study of social recovery from the 2004 tsunami in Sri Lanka that set out to identify and analyse examples of good practice with regard to community‐led recovery. It aims to elaborate what a community development approach to disaster recovery might look like as part of a more ‘deliberative’ and patient approach to long‐term social recovery.