bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linear stability of magnetohydrodynamic flow in a square duct with thin conducting walls
Authors: Priede Jānis , Arlt Thomas , Bühler Leo 
Published: December 2015

This study is concerned with the numerical linear stability analysis of liquid-metal flow in a square duct with thin electrically conducting walls subject to a uniform transverse magnetic field. We derive an asymptotic solution for the base flow that is valid for not only high but also moderate magnetic fields. This solution shows that, for low wall conductance ratios $c\ll 1$, an extremely strong magnetic field with Hartmann number $\mathit{Ha}\sim c^{-4}$ is required to attain the asymptotic flow regime considered in previous studies. We use a vector streamfunction–vorticity formulation and a Chebyshev collocation method to solve the eigenvalue problem for three-dimensional small-amplitude perturbations in ducts with realistic wall conductance ratios $c=1$, 0.1 and 0.01 and Hartmann numbers up to $10^{4}$. As for similar flows, instability in a sufficiently strong magnetic field is found to occur in the sidewall jets with characteristic thickness ${\it\delta}\sim \mathit{Ha}^{-1/2}$. This results in the critical Reynolds number and wavenumber increasing asymptotically with the magnetic field as $\mathit{Re}_{c}\sim 110\mathit{Ha}^{1/2}$ and $k_{c}\sim 0.5\mathit{Ha}^{1/2}$. The respective critical Reynolds number based on the total volume flux in a square duct with $c\ll 1$ is $\overline{\mathit{Re}}_{c}\approx 520$. Although this value is somewhat larger than $\overline{\mathit{Re}}_{c}\approx 313$ found by Ting et al. (Intl J. Engng Sci., vol. 29 (8), 1991, pp. 939–948) for the asymptotic sidewall jet profile, it still appears significantly lower than the Reynolds numbers at which turbulence is observed in experiments as well as in direct numerical simulations of this type of flow.
Effect of Thickness Profile and FG Function on Rotating Disks Under Thermal and Mechanical Loading
Authors: Jabbari M. , Ghannad M. , Nejad M. Z. 
Published: December 2015

AbstractIn this paper, a thermoelastic analysis of rotating disks with different thickness profiles made of functionally graded materials (FGMs) subjected to internal pressure is presented. Material properties (except Poisson’s ratio) and disk thickness profile are described by means of two functions namely power and exponential function. A comparative study of thermoelastic analysis is given for material properties and disk thickness profiles. The results of are compared with those obtained by finite element method (FEM) that shows good agreement. The effect of thickness profiles, gradient parameters and angular velocity on the thermoelastic performance of the disk have been studied.
DEFINABLE HENSELIAN VALUATION RINGS
Authors: PRESTEL ALEXANDER 
Published: December 2015

AbstractWe give model theoretic criteria for the existence of ∃∀ and ∀∃- formulas in the ring language to define uniformly the valuation rings ${\cal O}$ of models $\left( {K,\,{\cal O}} \right)$ of an elementary theory Σ of henselian valued fields. As one of the applications we obtain the existence of an ∃∀-formula defining uniformly the valuation rings ${\cal O}$ of valued henselian fields $\left( {K,\,{\cal O}} \right)$ whose residue class field k is finite, pseudofinite, or hilbertian. We also obtain ∀∃-formulas φ2 and φ4 such that φ2 defines uniformly k[[t]] in k(t) whenever k is finite or the function field of a real or complex curve, and φ4 replaces φ2 if k is any number field.
GREY SUBSETS OF POLISH SPACES
Authors: BEN YAACOV ITAÏ , MELLERAY JULIEN 
Published: December 2015

AbstractWe develop the basics of an analogue of descriptive set theory for functions on a Polish space X. We use this to define a version of the small index property in the context of Polish topometric groups, and show that Polish topometric groups with ample generics have this property. We also extend classical theorems of Effros and Hausdorff to the topometric context.
The Quality of Local Government and Firm Performance: The Case of China's Provinces
Authors: Choi Jongmoo Jay , Jiang Cao , Shenkar Oded 
Published: December 2015

ABSTRACTExtending La Porta, Lopez-de-Silanes, Shleifer, and Vishny (1999), we examine the effect of local government quality on firm performance, since regional and firm research provides a more fine-grained analysis especially in countries where local administration is an integral part of the bureaucratic apparatus. Using a dataset of 7,873 Chinese listed firm-years for 1994–2006, we find a positive relationship between the quality of provincial government and firm performance, controlling for location and firm-specific governance variables. Among various government quality variables, we find that having a special economic zone depicting low taxes and bureaucratic efficiency is the best predictor of firm performance, followed by the degree of marketization, efficient property registration, and environmental protection. Most intriguingly, political freedom has a significant impact on firm performance and productivity, even in a regime where democracy is not practiced. This has never been documented before at a microeconomic level and barely so at a macro level, vindicating Hayek's (1944) theory.
Zero-Separating Invariants for Linear Algebraic Groups
Authors: Elmer Jonathan , Kohls Martin 
Published: December 2015

AbstractAbstract Let G be a linear algebraic group over an algebraically closed field 𝕜 acting rationally on a G-module V with its null-cone. Let δ(G, V) and σ(G, V) denote the minimal number d such that for every and , respectively, there exists a homogeneous invariant f of positive degree at most d such that f(v) ≠ 0. Then δ(G) and σ(G) denote the supremum of these numbers taken over all G-modules V. For positive characteristics, we show that δ(G) = ∞ for any subgroup G of GL2(𝕜) that contains an infinite unipotent group, and σ(G) is finite if and only if G is finite. In characteristic zero, δ(G) = 1 for any group G, and we show that if σ(G) is finite, then G0 is unipotent. Our results also lead to a more elementary proof that βsep(G) is finite if and only if G is finite.
Functional ultrastructure of eggs and cellular organization of hexacanths of the cyclophyllidean cestodeThysanotaenia congolensis: a phylogenetic implication of obtained results
Authors: ŚWIDERSKI ZDZISŁAW , MIQUEL JORDI , CONN DAVID BRUCE 
Published: December 2015

SUMMARYThe functional ultrastructure of eggs and cellular organization of hexacanths from gravid proglottids ofThysanotaenia congolensis, from black rats from Cape Verde, were examined by transmission electron microscopy. Mature eggs with fully formed hexacanths are grouped within parenchymatous capsules of gravid proglottids. Oncospheral envelopes surrounding mature hexacanths are reduced to a very thin membranous embryophore as their protective function is taken over by the parenchymatous capsules originating from the medullary parenchyma of immature proglottids and composed of three layers. Six major cell types are present: a bi-nucleate medullary centre; a six-nucleate U-shaped penetration gland; a second type of penetration gland; two neurosecretory-type nerve cells; about 30 somatic cells; and about 12 germinative cells. Present results on the functional ultrastructure of eggs and cellular organization of hexacanths support the phylogenetic distinction betweenT. congolensisand cestodes of the subfamily Anoplocephalinae.
Combined effect of genetic variants in the GluN2B coding gene(GRIN2B)on prefrontal function during working memory performance
Authors: Pergola G. , Di Carlo P. , Andriola I. , Gelao B. , Torretta S. , Attrotto M. T. , Fazio L. , Raio A. , Albergo D. , Masellis R. , Rampino A. , Blasi G. , Bertolino A. 
Published: December 2015

BackgroundThe GluN2B subunit ofN-methyl-d-aspartate receptors is crucially involved in the physiology of the prefrontal cortex during working memory (WM). Consistently, genetic variants in the GluN2B coding gene (GRIN2B) have been associated with cognitive phenotypes. However, it is unclear howGRIN2Bgenetic variation affects gene expression and prefrontal cognitive processing. Using a composite score, we tested the combined effect ofGRIN2Bvariants on prefrontal activity during WM performance in healthy subjects.MethodWe computed a composite score to combine the effects of single nucleotide polymorphisms on post-mortem prefrontalGRIN2BmRNA expression. We then computed the composite score in independent samples of healthy participants in a peripheral blood expression study (n= 46), in a WM behavioural study (n= 116) and in a WM functional magnetic resonance imaging study (n= 122).ResultsFive polymorphisms were associated withGRIN2Bexpression: rs2160517, rs219931, rs11055792, rs17833967 and rs12814951 (all correctedp< 0.05). The score computed to account for their combined effect reliably indexed gene expression.GRIN2Bcomposite score correlated negatively with intelligence quotient, WM behavioural efficiency and dorsolateral prefrontal cortex activity. Moreover, there was a non-linear association betweenGRIN2Bgenetic score and prefrontal activity, i.e. both high and low putative genetic score levels were associated with high blood oxygen level-dependent signals in the prefrontal cortex.ConclusionsMultiple genetic variants inGRIN2Bare jointly associated with gene expression, prefrontal function and behaviour during WM. These results support the role ofGRIN2Bgenetic variants in WM prefrontal activity in human adults.
Metabolic variability of seed material from diverse sugar beet (Beta vulgaris L.) genotypes and of different germination capacities
Authors: Peukert Manuela , Dittbrenner Anke , Meinhard Juliane , Fischer Uwe , Mock Hans-Peter 
Published: December 2015

AbstractNew trends in crop breeding include analytical approaches to identify metabolic fingerprints that can be used for associations to the genetic background. The biochemical phenotype, as a result of plant endogenous factors and interaction with the environment, has the potential to increase the accuracy of forecasting regarding agronomical quality factors. In this study a metabolite profile analysis by gas chromatography–mass spectrometry (GC–MS) was conducted on sets of seed material from sugar beet. One set represented high-performing varieties with a close genetic background and with a similar quality in terms of germination capacity. The second set contained seed lots from different genotypes comprising different germination capacities. By multivariate statistical analyses high variance in both sample sets was revealed. These data were further allocated to corresponding metabolite classes. It could be shown that an untargeted GC–MS approach has the power to resolve differences in the molecular phenotypes of related offspring lines. Metabolic profiles were found to correlate more to genotypic differences than to differences in the germination capacity.
Dopant-Site Determination in Y- and Sc-Doped (Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ by Atom Location by Channeling Enhanced Microanalysis and the Role of Dopant Site on Secondary Phase Formation
Authors: Meffert Matthias , Störmer Heike , Gerthsen Dagmar 
Published: December 2015

Abstract(Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ (BSCF) is a promising material with mixed ionic and electronic conductivity which is considered for oxygen separation membranes. Selective improvement of material properties, e.g. oxygen diffusivity or suppression of secondary phase formation, can be achieved by B-site doping. This study is concerned with the formation of Co-oxide precipitates in undoped BSCF at typical homogenization temperatures of 1,000°C, which act as undesirable nucleation sites for other secondary phases in the application-relevant temperature range. Y-doping successfully suppresses Co-oxide formation, whereas only minor improvements are achieved by Sc-doping. To understand the reason for the different behavior of Y and Sc, the lattice sites of dopant cations in BSCF were experimentally determined in this work. Energy-dispersive X-ray spectroscopy in a transmission electron microscope was applied to locate dopant sites exploiting the atom location by channeling enhanced microanalysis technique. It is shown that Sc exclusively occupies B-cation sites, whereas Y is detected on A- and B-cation sites in Y-doped BSCF, although solely B-site doping was intended. A model is presented for the suppression of Co-oxide formation in Y-doped BSCF based on Y double-site occupancy.
PROPOSITIONAL CONTINGENTISM
Authors: FRITZ PETER 
Published: December 2015

AbstractAccording to propositional contingentism, it is contingent what propositions there are. This paper presents two ways of modeling contingency in what propositions there are using two classes of possible worlds models. The two classes of models are shown to be equivalent as models of contingency in what propositions there are, although they differ as to which other aspects of reality they represent. These constructions are based on recent work by Robert Stalnaker; the aim of this paper is to explain, expand, and, in one aspect, correct Stalnaker’s discussion.
The Readiness to Reconcile Inventory
Authors: Stammel Nadine , Bockers Estelle , Neuner Frank , Chhim Sotheara , Taing Sopheap , Knaevelsrud Christine 
Published: December 2015

Abstract. Although awareness of the importance of reconciliation in post-conflict societies has grown in recent decades, validated measures assessing victims’ attitudes toward reconciliation are lacking. To fill this gap, the Readiness to Reconcile Inventory (RRI) was developed and its factor structure and aspects of construct validity were psychometrically tested in two independent samples of survivors of the Khmer Rouge regime in Cambodia. Exploratory factor analysis in a sample of N = 247 survivors identified a 13-item, three-factor internal structure of the RRI that was confirmed by confirmatory factor analysis in an independent sample of N = 830 survivors of the Khmer Rouge regime. All RRI subscales showed good internal consistency (Cronbach’s αs from .80 to .83). Multiple-group analysis established configural, metric, and scalar invariance across sex. The RRI thus demonstrated good reliability and fulfilled some aspects of construct validity. It is a time-effective and easy-to-administer instrument for assessing readiness to reconcile in victims of war and conflict.
Imaging the uptake of nitrogen-fixing bacteria into larvae of the coral Acropora millepora
Authors: Lema Kimberley A , Clode Peta L , Kilburn Matt R , Thornton Ruth , Willis Bette L , Bourne David G 
Published: December 2015

Abstract
Diazotrophic bacteria are instrumental in generating biologically usable forms of nitrogen by converting abundant dinitrogen gas (N2) into available forms, such as ammonium. Although nitrogen is crucial for coral growth, direct observation of associations between diazotrophs and corals has previously been elusive. We applied fluorescence in situ hybridization (FISH) and nanoscale secondary ion mass spectrometry to observe the uptake of 15N-enriched diazotrophic Vibrio sp. isolated from Acropora millepora into conspecific coral larvae. Incorporation of Vibrio sp. cells was observed in coral larvae after 4-h incubation with enriched bacteria. Uptake was restricted to the aboral epidermis of larvae, where Vibrio cells clustered in elongated aggregations. Other bacterial associates were also observed in epidermal areas in FISH analyses. Although the fate and role of these bacteria requires additional investigation, this study describes a powerful approach to further explore cell associations and nutritional pathways in the early life stages of the coral holobiont.
Photon number statistics uncover the fluctuations in non-equilibrium lattice dynamics
Authors: Esposito Martina , Titimbo Kelvin , Zimmermann Klaus , Giusti Francesca , Randi Francesco , Boschetto Davide , Parmigiani Fulvio , Floreanini Roberto , Benatti Fabio , Fausti Daniele 
Published: December 2015

AbstractFluctuations of the atomic positions are at the core of a large class of unusual material properties ranging from quantum para-electricity to high temperature superconductivity. Their measurement in solids is the subject of an intense scientific debate focused on seeking a methodology capable of establishing a direct link between the variance of the atomic displacements and experimentally measurable observables. Here we address this issue by means of non-equilibrium optical experiments performed in shot-noise-limited regime. The variance of the time-dependent atomic positions and momenta is directly mapped into the quantum fluctuations of the photon number of the scattered probing light. A fully quantum description of the non-linear interaction between photonic and phononic fields is benchmarked by unveiling the squeezing of thermal phonons in α-quartz.
Finding Oxygen Reservoir by Using Extremely Small Test Cell Structure for Resistive Random Access Memory with Replaceable Bottom Electrode
Authors: Kinoshita Kentaro , Koh Sang-Gyu , Moriyama Takumi , Kishida Satoru 
Published: December 2015

AbstractAlthough the presence of an oxygen reservoir (OR) is assumed in many models that explain resistive switching of resistive random access memory (ReRAM) with electrode/metal oxide (MO)/electrode structures, the location of OR is not clear. We have previously reported a method, which involved the use of an AFM cantilever, for preparing an extremely small ReRAM cell that has a removable bottom electrode (BE). In this study, we used this cell structure to specify the location of OR. Because an anode is often assumed to work as OR, we investigated the effect of changing anodes without changing the MO layer and the cathode on the occurrence of reset. It was found that the reset occurred independently of the catalytic ability and Gibbs free energy (ΔG) of the anode. Our proposed structure enabled to determine that the reset was caused by repairing oxygen vacancies of which a filament consists due to the migration of oxygen ions from the surrounding area when high ΔG anode metal is used, whereas by oxidizing the anode due to the migration of oxygen ions from the MO layer when low ΔG anode metal is used, suggesting the location of OR depends on ΔG of the anode.
Quantifying electron transfer reactions in biological systems: what interactions play the major role?
Authors: Sjulstok Emil , Olsen Jógvan Magnus Haugaard , Solov’yov Ilia A. 
Published: December 2015

AbstractVarious biological processes involve the conversion of energy into forms that are usable for chemical transformations and are quantum mechanical in nature. Such processes involve light absorption, excited electronic states formation, excitation energy transfer, electrons and protons tunnelling which for example occur in photosynthesis, cellular respiration, DNA repair and possibly magnetic field sensing. Quantum biology uses computation to model biological interactions in light of quantum mechanical effects and has primarily developed over the past decade as a result of convergence between quantum physics and biology. In this paper we consider electron transfer in biological processes, from a theoretical view-point; namely in terms of quantum mechanical and semi-classical models. We systematically characterize the interactions between the moving electron and its biological environment to deduce the driving force for the electron transfer reaction and to establish those interactions that play the major role in propelling the electron. The suggested approach is seen as a general recipe to treat electron transfer events in biological systems computationally and we utilize it to describe specifically the electron transfer reactions in Arabidopsis thaliana cryptochrome–a signaling photoreceptor protein that became attractive recently due to its possible function as a biological magnetoreceptor.
Contractile dynamics change before morphological cues during fluorescence illumination
Authors: Knoll S. G. , Ahmed W. W. , Saif T. A. 
Published: December 2015

AbstractIllumination can have adverse effects on live cells. However, many experiments, e.g. traction force microscopy, rely on fluorescence microscopy. Current methods to assess undesired photo-induced cell changes rely on qualitative observation of changes in cell morphology. Here we utilize a quantitative technique to identify the effect of light on cell contractility prior to morphological changes. Fibroblasts were cultured on soft elastic hydrogels embedded with fluorescent beads. The adherent cells generated contractile forces that deform the substrate. Beads were used as fiducial markers to quantify the substrate deformation over time, which serves as a measure of cell force dynamics. We find that cells exposed to moderate fluorescence illumination (λ = 540–585 nm, I = 12.5 W/m2, duration = 60 s) exhibit rapid force relaxation. Strikingly, cells exhibit force relaxation after only 2 s of exposure, suggesting that photo-induced relaxation occurs nearly immediately. Evidence of photo-induced morphological changes were not observed for 15–30 min after illumination. Force relaxation and morphological changes were found to depend on wavelength and intensity of excitation light. This study demonstrates that changes in cell contractility reveal evidence of a photo-induced cell response long before any morphological cues.
HIV-1 Protease Dimerization Dynamics Reveals a Transient Druggable Binding Pocket at the Interface
Authors: Pietrucci Fabio , Vargiu Attilio Vittorio , Kranjc Agata 
Published: December 2015

AbstractThe binding mechanism of HIV-1 protease monomers leading to the catalytically competent dimeric enzyme has been investigated by means of state-of-the-art atomistic simulations. The emerging picture allows a deeper understanding of experimental observations and reveals that water molecules trapped at the interface have an important role in slowing down the kinetics of the association process. Unexpectedly, a cryptic binding pocket is identified at the interface of the complex, corresponding to a partially bound dimer that lacks enzymatic function. The pocket has a transient nature with a lifetime longer than 1 μs and it displays very favorable druggability features. Docking as well as MM-GBSA free-energy calculations further support the possibility to target the new binding site by means of inhibitors able to prevent the complete dimerization by capturing the inactive conformation. This discovery could open the way to the rational design of a new class of anti-HIV drugs.