bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum size effect in the photoluminescence properties of p-type semiconducting transparent CuAlO2 nanoparticles
Authors: Narayan Banerjee Arghya , Woo Joo Sang , Min Bong-Ki
Published: December 2012

Photoluminescence properties of CuAlO2 nanoparticles, deposited by a cost-effective direct current sputtering technique, have been studied. The nanoparticles show room-temperature photoluminescence peaks of near-band-edge emission due to recombination of free excitons. A blue-shift in the emission peaks as a decreasing function of the nanoparticle sizes is observed, which is attributed to the quantum confinement effect within the CuAlO2 nanoparticles. Theoretical calculations of bandgap enhancement values are found to be matching fairly well with that of the experimentally obtained values, confirming the existence of the quantum size effect within the nanomaterial. Approximate calculations show that the confinement effect falls within moderate-to-weak confinement regime. X-ray diffraction and electron microscopic measurements confirm the proper phase formation and nanocrystalline structure of the as-deposited nanoparticles. The room-temperature and size-dependent photoluminescence properties of this nanomaterial will be very useful for light emitting diode and similar optoelectronic applications.
High-field transport in a graphene nanolayer
Authors: Arora Vijay K. , Tan Michael L. P. , Gupta Chirag
Published: December 2012

High-field electron transport properties in a two-dimensional nanolayer are studied by an application of the anisotropic nonequilibrium distribution function, a natural extension of the Fermi-Dirac distribution by inclusion of energy gained/absorbed in a mean free path (mfp). The drift velocity for conical band structure of graphene is shown to rise linearly with the electric field in a low electric field that is below the critical electric field. The critical electric field, equal to thermal voltage divided by the mfp, marks the transition from ohmic linear transport to saturated behavior in a high electric field. As field rises beyond its critical value, the drift velocity is sublinear resulting in ultimate saturation; the ultimate saturation velocity is comparable to the Fermi velocity in graphene. The quantum emission is found not to affect the mobility, but is efficient in lowering the saturation velocity. Excellent agreement is obtained with the experimental data for graphene on silicon dioxide substrate.
Broadband gradient refractive index planar lens based on a compound liquid medium
Authors: Han Haoxue , Wu Lingling , Tian Xiaoyong , Li Dichen , Yin Ming , Wang Yu
Published: December 2012

We have proposed a new method to achieve gradient refractive-index (GRIN) optics via a compound liquid medium. By adjusting the composition of the liquid medium, the refractive index of the compound liquid was tuned in a very broad range from 1.58 to 5.15. The liquid medium also exhibited weak frequency dependence. Based on these properties, we designed a liquid GRIN planar lens and experimentally demonstrated the feasibility of this approach. The beam deflection of the lens was controlled by adjusting the distribution of the refractive-index of the lens. By changing the composition of the compound liquids in different cells of the lens framework, different spatial gradually varied refractive index profiles have been achieved. The proposed liquid planar lens has shown a good directive property at different receiving angles and demonstrated a broadband performance between 12 GHz and 15 GHz. This method results in a rapid and flexible realization of gradient refractive index structures by using liquid medium.
High piezoelectric performance in a new Bi-based perovskite of (1−x)Bi(Ni1/2Hf1/2)O3−xPbTiO3
Authors: Pan Zhao , Chen Jun , Fan Longlong , Liu Laijun , Fang Liang , Xing Xianran
Published: December 2012

Preparation, piezoelectric, and dielectric properties were investigated in a new Bi-based piezoelectric material of (1−x)Bi(Ni1/2Hf1/2)O3-xPbTiO3. The system can form a pure perovskite structure with the morphotropic phase boundary locating at x = 0.62, separating the rhombohedral and tetragonal phases. It is interesting to observe that the morphotropic phase boundary composition shows a very high piezoelectric coefficient of d33 (446 pC/N), which is comparable to BiScO3-PbTiO3 (460 pC/N). The Curie temperature of the morphotropic phase boundary is around 290 °C. Furthermore, the system has a relatively low coercive field, which makes the poling easily. Temperature dependence of dielectric properties also shows that the Bi(Ni1/2Hf1/2)O3-PbTiO3 system has a strong relaxor feature. Present new Bi-based perovskite of Bi(Ni1/2Hf1/2)O3-PbTiO3 is a competitive piezoelectric material with high piezoelectric performance.
External stress enhanced magnetoelectric coupling in multiferroic heterostructures
Authors: Bai G. , Gong X. , Liu Z. G. , Xia Y. D. , Yin J.
Published: December 2012

A phenomenological thermodynamic theory is used to investigate the effect of external mechanical stress on the magnetoelectric coupling in ferroelectric PbTiO3 or organic P(VDF-TrFE)/ferromagnetic Terfenol-D heterostructures. The results showed that the effects of external stress on the value of polarization strain sensitivity and magnetoelectric (ME) polarization coefficient for PbTiO3 and P(VDF-TrFE) are opposite, in which the electrostrictive constants play a significant role. However, the external stress has similar influence on the value of ME voltage coefficient in the two heterostructures. The compressive stress increases their ME voltage coefficient, and a peak appears near the stress of 200 MPa, in qualitative agreement with the experiment result. It is proposed that external stress might provide a new way to enhance or adjust magnetoelectric coupling in multiferroic heterostructures.
Ab initio study of collective excitations in a disparate mass molten salt
Authors: Bryk Taras , Klevets Ivan
Published: December 2012

Ab initio molecular dynamics simulations and the approach of generalized collective modes are applied for calculations of spectra of longitudinal and transverse collective excitations in molten LiBr. Dispersion and damping of low- and high-frequency branches of collective excitations as well as wave-number dependent relaxing modes were calculated. The main mode contributions to partial, total, and concentration dynamic structure factors were estimated in a wide region of wave numbers. A role of polarization effects is discussed from comparison of mode contributions to concentration dynamic structure factors calculated for molten LiBr from ab initio and classical rigid ion simulations.
Simulations of dilute sedimenting suspensions at finite-particle Reynolds numbers
Authors: Sungkorn R. , Derksen J. J.
Published: December 2012

An alternative numerical method for suspension flows with application to sedimenting suspensions at finite-particle Reynolds numbers Rep is presented. The method consists of an extended lattice-Boltzmann scheme for discretizing the locally averaged conservation equations and a Lagrangian particle tracking model for tracking the trajectories of individual particles. The method is able to capture the main features of the sedimenting suspensions with reasonable computational expenses. Experimental observations from the literature have been correctly reproduced. It is numerically demonstrated that, at finite Rep, there exists a range of domain sizes in which particle velocity fluctuation amplitudes ⟨ΔV∥, ⊥⟩ have a strong domain size dependence, and above which the fluctuation amplitudes become weakly dependent. The size range strongly relates with Rep and the particle volume fraction ϕp. Furthermore, a transition in the fluctuation amplitudes is found at Rep around 0.08. The magnitude and length scale dependence of the fluctuation amplitudes at finite Rep are well represented by introducing new fluctuation amplitude scaling functions C1, (∥, ⊥)(Rep, ϕp) and characteristic length scaling function C2(Rep, ϕp) in the correlation derived by Segre et al. from their experiments at low Rep [“Long-range correlations in sedimentation,” Phys. Rev. Lett. 79, 2574–2577 (1997)10.1103/PhysRevLett.79.2574] in the form \documentclass[12pt]{minimal}\begin{document}$\langle \Delta V_{\parallel , \perp } \rangle = \langle V_{\parallel } \rangle C_{1, ( \parallel , \perp )} ( Re_{p},\phi _{p} ) \phi _{p}^{1/3} \lbrace 1 - \text{exp} [ -L / ( C_{2} ( Re_{p}, \phi _{p} ) r_{p} \phi _{p}^{-1/3} )] \rbrace$\end{document}⟨ΔV∥,⊥⟩=⟨V∥⟩C1,(∥,⊥)(Rep,ϕp)ϕp1/3{1−exp[−L/(C2(Rep,ϕp)rpϕp−1/3)]}.
Heat capacity in weakly correlated liquids
Authors: Khrustalyov Yu. V. , Vaulina O. S. , Koss X. G.
Published: December 2012

Previously unavailable numerical data related to the heat capacity in two- and three-dimensional liquid Yukawa systems are obtained by means of fluctuation theory. The relations between thermal conductivity and diffusion constants are numerically studied and discussed. New approximation for heat capacity dependence on non-ideality parameter for weakly correlated systems of particles is proposed. Comparison of the obtained results to the existing theoretical and numerical data is discussed.
Droplets bouncing on a wet, inclined surface
Authors: Gilet Tristan , Bush John W. M.
Published: December 2012

We present the results of an experimental investigation of fluid drops impacting an inclined rigid surface covered with a thin layer of high viscosity fluid. We deduce the conditions under which droplet bouncing, splitting, and merger arise. Particular attention is given to rationalizing the observed contact time and coefficients of restitution, the latter of which require a detailed consideration of the drop energetics.
On shear-coupled migration of grain boundaries in nanocrystalline materials
Authors: Li Jianjun , Soh A. K.
Published: December 2012

Shear-coupled migration of grain boundary (GB) was theoretically modeled as a generic mode of plastic deformation in nanocrystalline materials. The energy change due to this process that carried both rotational and translational plastic flow through the normal migration and the shear coupled to the said migration, respectively, was calculated. The results obtained revealed that the shear-coupled migration was energetically more favorable than the pure migration of a grain boundary. The translational deformation can turn the initially energetically unfavorable process into a favorable one, and it can decrease the critical stress required to initiate the process of migration by around 30%–80% as compared with that for pure GB migration.
Ultrafast terahertz transmission ellipsometry of YMn2O5 electromagnons
Authors: Kim Hyosub , Yi Minwoo , Wang Xueyun , Cheong Sang-Wook , Ahn Jaewook
Published: December 2012

Terahertz time-domain polarization measurement experiments probe the electomagnon excitations in an orthorhombic multiferroic YMn2O5. Spectral phase rotation function measured from the mutually orthogonal polarization components of transmitted probe pulses sensitively resolves the electromagnon resonances which appear unresolvable in conventional transmission spectroscopy. The retrieved oscillator parameters based on electro-optic effects in a lossy birefringent material show good agreement with the previously reported Fourier transform infrared spectroscopy data.
Quantitative thermoacoustic tomography: Recovery of conductivity maps of heterogeneous media
Authors: Huang Lin , Yao Lei , Liu Lixin , Rong Jian , Jiang Huabei
Published: December 2012

We report on experimental demonstration of thermoacoustic tomography for quantitatively reconstructing the conductivity images of heterogeneous media. Thermoacoustic images are obtained from a series of tissue-like phantom experiments using a finite element-based reconstruction algorithm coupled with a scanning thermoacoustic imaging system. The experimental results show that conductivity images can be quantitatively reconstructed based on the finite-element (FE) solution to the Helmholtz electromagnetic wave equation coupled with the thermoacoustic wave equation.
‘Small-Town Defenders’: The Production of Citizenship and Belonging in Hazleton, Pennsylvania
Authors: Steil Justin , Ridgley Jennifer
Published: December 2012

Over the past five years an aggressive movement has emerged to return immigration enforcement powers to the local level in the US, and to some extent in Europe as well. Hazleton, PA, was home to the first local government in the US to pass an ‘Illegal Immigration Relief Act’ (IIRA), which subsequently became a model for other cities across the country seeking to implement their own immigration regulations. We argue that Hazleton's IIRA was as much productive of tensions over migration as it was the product of them. Neoliberal economic restructuring left Hazleton residents feeling a sense of ‘class downgrading’ but the ordinance itself was central in creating divisions between the native-born white population and recent Latino arrivals. As much as the ordinance served to exclude undocumented immigrants, it simultaneously served to unify native-born white residents by repositioning Hazleton as ‘small-town USA’, no longer marginal but, instead, central to the defense of American ‘quality of life’. Control over housing became a key form of spatial and territorial control through the creation of a location in which outsiders could be defined as not-belonging and local citizenship could be imbued with new meaning. The paper illuminates the ways in which ‘Americanness’ and citizenship are locally constructed and highlights the significance of territorial control and collective identity in addition to economic restructuring in the resurgence of local immigration regulations.
Illuminated Atmospheres: Anticipating and Reproducing the Flow of Affective Experience in Blackpool
Authors: Edensor Tim
Published: December 2012

This paper considers the atmospheric qualities of illuminated space, grounding notions of affect in investigating the longstanding autumnal event of Blackpool Illuminations. I consider the affective qualities of lighting before discussing the ‘atmosphere’ of the Illuminations. I critically explore the division between affect and emotion, the insistence on affect's precognitive qualities, and the notion that affective atmospheres produce a ‘mute attunement’ to place. In foregrounding the dense social production of atmosphere at Blackpool Illuminations, I highlight the flow of affect and emotion in place, show how lighting is ideally constituted to blur divisions between the representational and nonrepresentational, identify the anticipation of affect, and demonstrate that affective atmospheres are coproduced by visitors as part of a reiterative, festive, convivial, and playful social practice in familiar space.
Graduated and Paternal Sovereignty: Stephen Harper, Operation Nanook 10, and the Canadian Arctic
Authors: Dodds Klaus
Published: December 2012

The idea of ‘graduated sovereignty’ has been used in economic geography and related fields to describe neoliberal capitalism and its negative implications for countries in the Global South. Scholars such as Aihwa Ong use the term primarily to reflect on how states and their elites in the Global South flexibly manage territories and populations at different spatial scales, including export-processing zones. In this paper, attention is given to how ‘graduated sovereignty’ is a useful lens to interrogate territorial claims (including the preservation of territorial integrity) and the spatially varied performance of state power. The Canadian government led by Prime Minister Stephen Harper and his government's Arctic policies and strategies are a case in point. Graduated sovereignty is only one element, however, as the paper considers how a form of paternal sovereignty plays a part in managing the normative ideas of territorial integrity, the presence of exceptional circumstances, and the role of future uncertainties. Using Operation Nanook 10 as a short case study, the paper considers how the government puts to work an uncertain future regarding the Canadian Arctic is materialised and then made actionable by invoking both graduated and paternal forms of sovereignty.
Geopower: A Panel on Elizabeth Grosz's Chaos, Territory, Art: Deleuze and the Framing of the Earth
Authors: Yusoff Kathryn , Grosz Elizabeth , Clark Nigel , Saldanha Arun , Yusoff Kathryn , Nash Catherine , Grosz Elizabeth
Published: December 2012

Rather than understand art as cultural accomplishment, Elizabeth Grosz argues that it is born from the intensities of chaos and disruptive forms of sexual selection—a corporeality that vibrates to the hum of the universe. Grosz contends that it is precisely this excessive, nonproductive expenditure of sexual attraction that is the condition for art's work. This intimate corporeality, composed of nonhuman forces, is what draws and transforms the cosmos, prompting experimentation with materiality, sensation, and life. In the book Chaos, Territory, Art: Deleuze and the Framing of the Earth (2008, Duke University Press, Durham, NC), that is the subject of this panel discussion, Grosz sets out an ontology of art, looking at its forms of emergence as territorialising force, sexual selection, and nonhuman power. In Grosz's terms, art is an art of existence. This is not a narrow understanding of art as a practice that is about taste, cultural accomplishment, or a reflection of society, but an art that is—at its most provocative—an extraction from the universe and an elaboration on it. This ‘geoaesthetics’ which is both biospheric and biopolitical, presents a formable challenge to geographers interested in art, sexuality, time, and the territorialisation of the earth. How might we understand this distinctly different kind of biopolitics? And what might Grosz's concept of ‘geopower’ offer in terms of a renegotiation of a more active ‘geo’ in geopolitics? Grosz argues that art is not tied to the reproduction of the known, but to the possibility of the new, overcoming the containment of the present to elaborate on futures yet to come. In this rethinking of sexual selection Grosz suggests an intensely political role for art as a bioaesthetics that is charged with the creation of new worlds and forms of life. Grosz makes a radical argument for a feminist philosophy of the biosphere and for our thinking the world otherwise.
Subjectivity, Modernity, and the Politics of Difference in a Periurban Village in China: Towards a Progressive Sense of Place?
Authors: Qian Junxi , Qian Liyun , Zhu G
Published: December 2012

In this paper we investigate the cultural imageries of place and their relation to the politics of difference within China's emerging space of modernity. Using a case study of the place politics in Xiaozhou Village, Guangzhou, we consider how particular subject positions in relation to the ideologies of modernity and rurality shape particular imaginative structures of place and cognitive mappings of social relations. We argue that Massey's theory of a global sense of place needs to include a dimension concerning how concrete subject positions can be negotiated and challenged in the imagination of place. We also contend for a face-to-face politics of difference to analyze the anxieties and tensions between particularized subject positions. In concluding this paper we also suggest that the political potential of this model of place politics lies in its recognition that, while conflicts which are grounded in place-based social relations will not vanish, place should not to be mobilized as a citadel within which an enclosed subjectivity is protected from the interference of otherness. Thus the Other is also ascribed with the political potential to reproduce the cognitive mapping of the lifeworld of mine.
Effect of copper source on phytase stability in the premix of weanling piglets
Authors: Lu Lin , Hao Shoufeng , Zhang Liyang , Luo Xugang
Published: December 2012

An in vitro experiment was conducted to investigate the effect of tribasic copper (Cu) chloride [TBCC, Cu2(OH)3Cl] on phytase stability in the premix of weanling piglets at different temperatures in comparison with Cu sulfate. The 225-kg 1% premixes were supplemented with phytase at 50 000 PU/kg and divided into three parts of 75 kg each. One part was supplemented with 6 mg Cu/kg as Cu sulfate (the control), and the other two parts were supplemented with 250 mg Cu/kg either as TBCC or as Cu sulfate. Either 6 or 250 mg Cu/kg is based on the complete diet of weanling piglets. The three premixes were stored at room temperature (20−25°C), natural high temperature (28−36°C), or artificial high temperature (38 ± 2°C) for 0, 10, 20, 30, or 40 days. Copper source, storage temperature and duration of storage, the interaction between Cu source and duration of storage, and the interaction between temperature and duration of storage affected (P < 0.01) phytase activities in the 1% premixes. Phytase activities in the premixes supplemented with TBCC were significantly higher (P < 0.001) than those in the premixes supplemented with CuSO4 at 10 or 20 days of storage. Phytase activities in premixes decreased (P < 0.001) exponentially with duration of storage regardless of Cu source or storage temperature. When the premixes were stored at different duration of storage, phytase activities in the premixes decreased (P < 0.001) linearly as temperature increased. The results from this study indicate that TBCC could maintain the stability of phytase in the piglet premix much more effectively than Cu sulfate regardless of temperature and storage duration.
The Lived Experience of Native Hawaiians Exiting Prison and Reentering the Community: How Do You Really Decriminalize Someone Who’s Consistently Being Called a Criminal?
Authors: Ka'opua Lana Sue , Petteruti Amanda , Takushi Nalani , Spencer James H. , Park Soon H. , Diaz Tressa P. , Kamakele Shalia K. , Kukahiko Kaipo C.
Published: December 2012

The overrepresentation of Native Hawaiians in Hawai‘i’s criminal justice system is among the most stunning of ethnic/racial disparities in the state. To describe the human impact of Native Hawaiians involvement in the criminal justice system, the authors interviewed persons with criminal histories, correctional officials, social workers, and others. Findings reveal systemic challenges to prison exit and community reentry, including lack of services stipulated for release and upon reentry, marginalization associated with cultural trauma, resource deficits, and stigma. The National Association of Social Workers encourages social work leadership in policy formulation and service development. Suggested are strategies for influencing community attitudes, program access, and culturally-grounded services.
Aging, Mental Health, and the Criminal Justice System: A Content Analysis of the Literature
Authors: Maschi Tina , Sutfin Samantha L. , O'Connell Brendan
Published: December 2012

Whereas older adults in the criminal justice system are a significant public health concern, there has been little research examining mental health among this population. This content analysis attempts to fill that gap by examining the international peer-reviewed empirical journal articles on mental health and older adults in the criminal justice system. English-language articles that examined mental health among older adults in the criminal justice system were locating through a comprehensive search of peer-reviewed journals of Academic Search Premier Literature data-bases, which included MEDLINE and PsycLIT. Trained researchers extracted data on the research methods and major findings on mental health among older adults in the criminal justice system. Thirty-one empirical studies were identified as meeting the study criteria. Content analysis was conducted using deductive (fre-quency counts) and analytic strategies (thematic analysis of major findings across studies). Results indicated that between 1988 and 2012, 31 empirical studies were published on mental health among older adults in the criminal justice system. Most of the studies were conducted in secure care settings that were prisons (n= 16) or forensic psychiatric hospital or units (n= 8). Of the 31 studies, schizophrenia, major depressive disorder, dementia, and substance use disorder were the most widely diagnosed mental illness. Comorbid physical ailments were noted in the 10 studies. Common themes across studies were related to the mental health detection and access to services, group differences, comorbid conditions, and the relationship of age, mental health, and criminal behavior, including potential risk and protective factors. Relatively few stud-ies have focused on the mental health needs of older adults in the criminal justice system, especially at the time of arrest, court pro-cessing, probation, and parole. These results suggest that mental illness, including serious mental illness, needs to be addressed at all stages of the criminal justice process.
Distribution of Pathogens in Central Line–Associated Bloodstream Infections among Patients with and without Neutropenia following Chemotherapy Evidence for a Proposed Modification to the Current Surveillance Definition
Authors: Steinberg James P. , Robichaux Chad , Tejedor Sheri Chernetsky , Reyes Mary Dent , Jacob Jesse T.
Published: December 2012

Objective.

Many bloodstream infections (BSIs) occurring in patients with febrile neutropenia following cytotoxic chemotherapy are due to translocation of intestinal microbiota. However, these infections meet the National Healthcare Safety Network (NHSN) definition of central line-associated BSIs (CLABSIs). We sought to determine the differences in the microbiology of NHSN-defined CLABSIs in patients with and without neutropenia and, using these data, to propose a modification of the CLABSI definition.

Design.

Retrospective review.

Setting.

Two large university hospitals over 18 months.

Methods.

All hospital-acquired BSIs occurring in patients with central venous catheters in place were classified using the NHSN CLABSI definition. Patients with postchemotherapy neutropenia (500 neutrophils/mm3or lower) at the time of blood culture were considered neutropenic. Pathogens overrepresented in the neutropenic group were identified to inform development of a modified CLABSI definition.

Results.

Organisms that were more commonly observed in the neutropenic group compared with the nonneutropenic group includedEscherichia coli(22.7% vs 2.5%;P< .001) but not other Enterobacteriaceae,Enterococcus faecium(18.2% vs 6.1%;P= .002), and streptococci (18.2% vs 0%;P< .001). Application of a modified CLABSI definition (removing BSI with enterococci, streptococci, orE. coli) excluded 33 of 66 neutropenic CLABSIs and decreased the CLABSI rate in one study hospital with large transplant and oncology populations from 2.12 to 1.79 cases per 1,000 line-days.

Conclusions.

Common gastrointestinal organisms were more common in the neutropenia group, suggesting that many BSIs meeting the NHSN criteria for CLABSI in the setting of neutropenia may represent translocation of gut organisms. These findings support modification of the NHSN CLABSI definition.
A novel link prediction algorithm for reconstructing protein–protein interaction networks by topological similarity
Authors: Lei Chengwei , Ruan Jianhua
Published: December 2012

Motivation: Recent advances in technology have dramatically increased the availability of protein–protein interaction (PPI) data and stimulated the development of many methods for improving the systems level understanding the cell. However, those efforts have been significantly hindered by the high level of noise, sparseness and highly skewed degree distribution of PPI networks. Here, we present a novel algorithm to reduce the noise present in PPI networks. The key idea of our algorithm is that two proteins sharing some higher-order topological similarities, measured by a novel random walk-based procedure, are likely interacting with each other and may belong to the same protein complex.

Results: Applying our algorithm to a yeast PPI network, we found that the edges in the reconstructed network have higher biological relevance than in the original network, assessed by multiple types of information, including gene ontology, gene expression, essentiality, conservation between species and known protein complexes. Comparison with existing methods shows that the network reconstructed by our method has the highest quality. Using two independent graph clustering algorithms, we found that the reconstructed network has resulted in significantly improved prediction accuracy of protein complexes. Furthermore, our method is applicable to PPI networks obtained with different experimental systems, such as affinity purification, yeast two-hybrid (Y2H) and protein-fragment complementation assay (PCA), and evidence shows that the predicted edges are likely bona fide physical interactions. Finally, an application to a human PPI network increased the coverage of the network by at least 100%.

Availability:  www.cs.utsa.edu/∼jruan/RWS/.

Contact:  Jianhua.Ruan@utsa.edu

Supplementary information: Supplementary data are available at Bioinformatics online.
Robust Estimation with Nonrandom Measurement Error and Weak Instruments
Authors: Betz Timm
Published: December 2012

Two common problems in applications of two-stage least squares (2SLS) are nonrandom measurement error in the endogenous variable and weak instruments. In the presence of nonrandom measurement error, 2SLS yields inconsistent estimates. In the presence of weak instruments, confidence intervals andp-values can be severely misleading. This article introduces a rank-based estimator, grounded in randomization inference, which addresses both problems within a unified framework. Monte Carlo studies illustrate the deficiencies of 2SLS and the virtues of the rank-based estimator in terms of bias and efficiency. A replication of a study of the effect of economic shocks on democratic transitions demonstrates the practical implications of accounting for nonrandom measurement error and weak instruments.
Inter-species transmission of viral hemorrhagic septicemia virus (VHSV) from turbot (Scophthalmus maximus) to rainbow trout (Onchorhynchus mykiss)
Authors: Schönherz Anna A. , Lorenzen Niels , Einer-Jensen Katja
Published: December 2012

Successful viral infection is a complex mechanism, involving many host–pathogen interactions that developed during coevolution of host and pathogen, and often result in host-species specificity. Nevertheless, many viruses are able to infect several host species and sporadically cross species barriers. The viral hemorrhagic septicemia virus (VHSV), a rhabdovirus with high economic impact on the aquaculture industry, has developed an exceptionally wide host range across marine and freshwater environments. Transmission of VHSV between host species therefore represents a potential risk for aquaculture, which currently is not addressed in biosecurity managements. The objective of this study was to investigate the inter-species transmission potential of VHSV and evaluate whether infected marine wild fish pose a potential risk on marine cultured rainbow trout. A cohabitation infection trial with turbot as donor and rainbow trout as recipient host species was conducted. Turbot were intraperitoneally injected with either a marine-adapted (MA) or a trout-adapted (TA) VHSV isolate and subsequently grouped with naïve rainbow trout. Both VHSV isolates were able to replicate and cause mortality in turbot, while only the TA isolate was able to cross the species barrier and infect rainbow trout with fatal outcome. The results demonstrate that a marine fish species can function as reservoir and transmitter of TA VHSV isolates.
Proteomic profiles and kinetics of development of bacteriophage T4 and its rI and rIII mutants in slowly growing Escherichia coli
Authors: Golec Piotr , Karczewska-Golec Joanna , Voigt Birgit , Albrecht Dirk , Schweder Thomas , Hecker Michael , Węgrzyn Grzegorz , Łoś Marcin
Published: December 2012

Bacteriophage T4 survival in its natural environment requires adjustment of phage development to the slow bacterial growth rate or the initiation of mechanisms of pseudolysogeny or lysis inhibition (LIN). While phage-encoded RI and probably RIII proteins seem to be crucial players in pseudolysogeny and LIN phenomena, the identity of proteins involved in the regulation of T4 development in slowly growing bacteria has remained unknown. In this work, using a chemostat system, we studied the development of wild-type T4 (T4wt) and itsrI(T4rI) andrIII(T4rIII) mutants in slowly growing bacteria, where T4 did not initiate LIN or pseudolysogeny. We determined eclipse periods, phage propagation times, latent periods and burst sizes of T4wt, T4rIand T4rIII. We also compared intracellular proteomes of slowly growingEscherichia coliinfected with either T4wt or the mutants. Using two-dimensional PAGE analyses we found 18 differentially expressed proteins from lysates of infected cells. Proteins whose amounts were different in cells harbouring T4wt and the mutants are involved in processes of replication, phage–host interactions or they constitute virion components. Our data indicate that functional RI and RIII proteins – apart from their already known roles in LIN and pseudolysogeny – are also necessary for the regulation of phage T4 development in slowly growing bacteria. This regulation may be more complicated than previously anticipated, with many factors influencing T4 development in its natural habitat.
Consistent joint elastic‐electrical differential effective‐medium modelling of compacting reservoir sandstones
Authors: Jensen Erling Hugo , Gelius Leiv‐J. , Johansen Tor Arne , Wang Zhong
Published: December 2012

Improved reservoir characterization and monitoring can be achieved by combining seismic and controlled‐source electromagnetic techniques. This requires developing coherent rock physics descriptions. In this paper we demonstrate consistent joint elastic‐electrical modelling according to the differential effective‐medium theory. We test our modelling against data from a compaction experiment on a set of 11 sandstone core samples from the same quarry location. The presented approach is analogous to calibrating a rock physics model to a particular reservoir based on data from possible well logs and core samples. For simplicity we choose to use multivariable non‐linear regression in the inversion. It shows that this technique is able to identify solutions that are physically sound. However, a more rigorous inversion method might be considered in future implementations. To identify the critical parameters we test the elastic‐electrical sensitivity of the various unknown variables involved. The most sensitive parameters identified are then perturbed during the modelling. The mineralogy consists mainly of quartz, which we assume to be spherical and kaolinite. We use the resistivity to calibrate the aspect ratio of the clay grains and estimate the porosity reduction due to compaction. These values are in turn used in inverse modelling of the bulk and shear moduli. The solid minerals make up the inclusion material in the differential effective‐ medium modelling for both the elastic and electrical properties. Hence, this formulation constitutes a consistent joint elastic‐electrical modelling scheme. We achieve good fits between the model results and the laboratory measurements for most of the samples. The reason for the less good fit with some of the samples might be due to measurement errors in the laboratory. This is supported by the observed abnormal stiffness compaction trends associated with those samples.
Quantitative genetics of sexual display, ejaculate quality and size in a lekking species
Authors: Chargé Rémi , Teplitsky Céline , Hingrat Yves , Saint Jalme Michel , Lacroix Frédéric , Sorci Gabriele
Published: December 2012

The investment into extravagant sexual display and competitive sperm are two essential components of pre‐ and post‐copulatory sexual selection. Even though the selective forces acting on sexual display and sperm characteristics have been extensively studied in recent years, the genetic architecture underlying the expression of these traits has been rarely explored.

Here, we estimated the genetic variances and covariances of traits linked with ejaculate size and quality, and sexual display in the houbara bustard (Chlamydotis undulata undulata, Jacquin 1784).

Using a very large pedigree‐based data set, we show that sexual signalling and ejaculate size (but not ejaculate quality) are heritable and genetically positively correlated. The matrix of genetic covariances also provided support for some across‐sex correlations: male and female gamete numbers are positively correlated, and more surprisingly, male display and female gamete numbers are also positively correlated.

These results can have important implications for the understanding of the evolution of sperm traits and sexual display in animals.
New EU Policies Towards Animal Welfare: The Relative Importance of Pig Castration  Les nouvelles politiques européennes en matière de bien‐être animal : l’importance relative de la castration des porcelets   Neue EU‐Politiken zum Tierwohl: Die relative Bedeutung der Ferkelkastration
Authors: Kallas Zein , Gil José Maria , Panella‐Riera Nuria , Blanch Marta , Tacken Gemma , Chevillon Patrick , De Roest Kees , Angels Oliver M.
Published: December 2012

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New EU Policies Towards Animal Welfare: The Relative Importance of Pig Castration

Animal welfare is becoming one of the most contentious issues in animal husbandry and meat production industries. We assess the relative importance of animal welfare, with respect to pig castration and the avoidance of boar taint, alongside different attributes of pork meat, amongst consumers in six EU countries. We use the Analytical Hierarchy Process (AHP) as a multi‐criteria decision‐support method aimed at deconstructing the purchasing decisions of consumers. Our results show that in all surveyed countries, consumers are generally not concerned about the ‘gender of the animal’. This particular attribute represented approximately 10 per cent or less of the final buying decision, while ‘flavour and odour’ was the most important attribute, representing approximately 45 per cent of the final buying decision. The results also demonstrated that pig castration is not necessarily perceived as a relevant aspect of animal welfare. However, any future regulation on banning castration to increase pig welfare could undesirably affect the ‘flavour and odour’ of the meat and thus might negatively impact the most important factor in consumers’ purchasing decisions. Thus, effective public awareness campaigns about the relationship between pig welfare and castration and between castration and sensory meat qualities are needed to help policymakers address the true interests of consumers in future food policies.
New haptophyte lineages and multiple independent colonizations of freshwater ecosystems
Authors: Simon Marianne , López‐García Purificación , Moreira David , Jardillier Ludwig
Published: December 2012

The diversity and ecological relevance of small haptophytes in marine systems is increasingly recognized. Similar investigations in freshwater remain scarce, despite some recent studies showing the existence of divergent haptophyte lineages and indicating that these microalgae can occur at high abundance in lakes. We studied the diversity of haptophytes in a wide variety of marine, salty continental and, most particularly, freshwater environments by amplifying, cloning and sequencing 18S rRNA genes. For this purpose, we designed two sets of primers specific for the two recognized haptophyte classes, Prymnesiophyceae and Pavlovophyceae. We detected pavlovophyte sequences only in freshwater systems as well as several novel prymnesiophyte phylotypes in both freshwater and marine environments. In addition, we retrieved a cluster of sequences (HAP‐3) from the Marmara Sea branching deeply in the haptophyte tree with no clear affiliation to either of the two recognized classes. Five of the freshwater prymnesiophyte phylotypes detected formed a divergent monophyletic group (EV) without close described representatives that branched within the Isochrysidales, a group of generally marine and most often calcifying coccolithophorids. The presence of several sequences of freshwater haptophytes scattered among marine taxa in phylogenetic trees confirms the occurrence of several independent haptophyte transitions between marine and freshwater environments.
Deletion of p66Shc in mice increases the frequency of size‐change mutations in the lacZ transgene
Authors: Beltrami Elena , Ruggiero Antonella , Busuttil Rita , Migliaccio Enrica , Pelicci Pier Giuseppe , Vijg Jan , Giorgio Marco
Published: December 2012

Upon oxidative challenge the genome accumulates adducts and breaks that activate the DNA damage response to repair, arrest, or eliminate the damaged cell. Thus, reactive oxygen species (ROS) generated by endogenous oxygen metabolism are thought to affect mutation frequency. However, few studies determined the mutation frequency when oxidative stress is reduced. To test whether in vivo spontaneous mutation frequency is altered in mice with reduced oxidative stress and cell death rate, we crossed p66Shc knockout (p66KO) mice, characterized by reduced intracellular concentration of ROS and by impaired apoptosis, with a transgenic line harboring multiple copies of the lacZ mutation reporter gene as part of a plasmid that can be recovered from organs into Escherichia coli to measure mutation rate. Liver and small intestine from 2‐ to 24‐month‐old, lacZ (p66Shc+/+) and lacZp66KO mice, were investigated revealing no difference in overall mutation frequency but a significant increase in the frequency of size‐change mutations in the intestine of lacZp66KO mice. This difference was further increased upon irradiation of mice with X‐ray. In addition, we found that knocking down cyclophilin D, a gene that facilitates mitochondrial apoptosis acting downstream of p66Shc, increased the size‐change mutation frequency in small intestine. Size‐change mutations also accumulated in death‐resistant embryonic fibroblasts from lacZp66KO mice treated with H2O2. These results indicate that p66Shc plays a role in the accumulation of DNA rearrangements and suggest that p66Shc functions to clear damaged cells rather than affect DNA metabolism.
Genetic population structure of the endangered fire salamander (Salamandra infraimmaculata) at the southernmost extreme of its distribution
Authors: Blank L. , Sinai I. , Bar‐David S. , Peleg N. , Segev O. , Sadeh A. , Kopelman N. M. , Templeton A. R. , Merilä J. , Blaustein L.
Published: December 2012

The negative effects of habitat fragmentation and population isolation on population viability, genetic variability and structuring are well documented, and conservation plans failing to take into account spatial population structure and connectivity can be ineffectual. Of special concern are populations at the periphery of the species range that might show reduced genetic diversity, thus affecting their adaptive potential at environmental margins. We investigated genetic variability and differentiation of the globally near threatened and locally endangered fire salamander Salamandra infraimmaculata in northern Israel, an area that represents the periphery of this species' distribution range. Analyses of variability in 15 microsatellite loci from 20 sites revealed substantial population structuring, most of which was due to a strong subdivision between two regions separated by a heavily urbanized valley. In addition, levels of genetic variability within populations were lowest in the peripheral, southernmost populations. These results suggest that the conservation plans for this species should recognize the lower diversity and increased divergence in the peripheral regions, and take into account the observed spatial population structure when devising strategies and measures to ensure the species persistence.
Springtail (Collembola) assemblages along an elevational gradient in Australian subtropical rainforest
Authors: Maunsell Sarah C , Kitching Roger L , Greenslade Penelope , Nakamura Akihiro , Burwell Chris J
Published: December 2012

Springtails are one of the most abundant groups of arthropods inhabiting soil and litter substrates within rainforest ecosystems, making significant contributions to ecological processes such as decomposition. The aim of this study is to assess the potential sensitivity of springtail assemblages to climate change by presenting some of the first data on the elevation stratification of springtail assemblages in subtropical rainforest. A standardised sampling protocol was used to compare the assemblages of families and species of springtails living within leaf‐litter at three elevations in continuous rainforest in south‐east Queensland, Australia. Leaf‐litter was collected and springtails extracted from four replicate plots at approximately 700, 900 and 1100 m a.s.l. on two sampling occasions (January 2008 and December 2008). Environment variables (elevation of plots, tree species richness, composition and basal area, soil temperature and moisture and a range of physical and chemical properties of the soil) that may correlate with springtail distributions were incorporated into the analyses.

Springtail assemblages showed clear elevation patterns, despite some differences between the two sampling occasions. Springtail assemblages characteristic of different elevations particularly when examined at a finer taxonomic resolution (species compared with family‐level identification) were identified. Plot elevation (m a.s.l.) correlated most strongly with patterns in springtail species assemblages, but was also highly correlated with several other environmental factors. The results indicate that springtails, as a group, respond strongly to the physico‐chemical and/or biological changes that occur with increasing elevation, even over a relatively small elevation range, demonstrating that they have potential as monitoring targets as forests experience climate change.
Secondary production of crustacean zooplankton and biomass of major rotifer species in Lake Bosumtwi/Bosomtwe, Ghana, West Africa
Authors: Sanful Peter O. , Frempong Emmanuel , Aikins Samuel , Hecky Robert. E.
Published: December 2012

Studies have shown a strong linkage between zooplankton and fisheries' potential in tropical lakes. High zooplankton production provides the basis for fish production, but knowledge of zooplankton production dynamics in African lakes is extremely limited. Crustacean zooplankton production and the biomass of dominant rotifers in Lake Bosumtwi were assessed over a 2‐year period. The crustaceans comprised an endemic and extremely abundant cyclopoid copepod, Mesocyclops bosumtwii and the cladoceran Moina micrura. Mean standing stock of the crustaceans was 429 mg dw m−3, whilst annual production averaged 2.1 g dw m−3 y−1. Production doubled from 1.4 g dw m−3 y−1 in 2005 to 2.8 g dw m−3 y−1 in 2006. Copepods accounted for 98.5% of crustacean production. The biomass of the dominant rotifers Brachionus calyciflorus and Hexarthra intermedia was less than 1% of total zooplankton biomass. Daily turnover rate and turnover time of the crustaceans was 0.19 day−1 and 6.2 days respectively. Crustacean production yielded no statistical relationship with phytoplankton biomass. Production was well within the range of tropical lakes. Peak crustacean production synchronized maximum rainfall, lake mixing and phytoplankton production. Most importantly, no one year's set of dynamics can be used to characterize zooplankton production in the lake.