1,487 research outputs found

    Holomorphic factorization of determinants of Laplacians using quasi-Fuchsian uniformization

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    For a quasi-Fuchsian group \Ga with ordinary set Ω\Omega, and Δn\Delta_{n} the Laplacian on \n differentials on \Ga\bk\Omega, we define a notion of a Bers dual basis ϕ1,...c,ϕ2d\phi_{1},...c,\phi_{2d} for kerΔn\ker\Delta_{n}. We prove that detΔn/det\det\Delta_{n}/\det , is, up to an anomaly computed by Takhtajan and the second author in \cite{TT1}, the modulus squared of a holomorphic function F(n), where F(n) is a quasi-Fuchsian analogue of the Selberg zeta Z(n). This generalizes the D'Hoker-Phong formula detΔn=cg,nZ(n)\det\Delta_{n}=c_{g,n}Z(n), and is a quasi-Fuchsian counterpart of the result for Schottky groups proved by Takhtajan and the first author in \cite{MT}.Comment: 15 page

    Spin texture on the Fermi surface of tensile strained HgTe

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    We present ab initio and k.p calculations of the spin texture on the Fermi surface of tensile strained HgTe, which is obtained by stretching the zincblende lattice along the (111) axis. Tensile strained HgTe is a semimetal with pointlike accidental degeneracies between a mirror symmetry protected twofold degenerate band and two nondegenerate bands near the Fermi level. The Fermi surface consists of two ellipsoids which contact at the point where the Fermi level crosses the twofold degenerate band along the (111) axis. However, the spin texture of occupied states indicates that neither ellipsoid carries a compensating Chern number. Consequently, the spin texture is locked in the plane perpendicular to the (111) axis, exhibits a nonzero winding number in that plane, and changes winding number from one end of the Fermi ellipsoids to the other. The change in the winding of the spin texture suggests the existence of singular points. An ordered alloy of HgTe with ZnTe has the same effect as stretching the zincblende lattice in the (111) direction. We present ab initio calculations of ordered Hg_xZn_1-xTe that confirm the existence of a spin texture locked in a 2D plane on the Fermi surface with different winding numbers on either end.Comment: 8 pages, 8 figure

    Which work characteristics predict employee outcomes for the public-sector employee? An examination of generic and occupation-specific characteristics

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    The wide-ranging changes that have occurred in the public sector over recent years have placed increasing demands on public-sector employees. A survey of employees within a relatively commercially-oriented public-sector organization in Australia was used to test a demand-oriented generic model of employee well-being and a variety of situation-specific variables. The presence of support at work and the amount of control an employee had over their job were found to be key predictors of employee-level outcomes. Perceptions of pay and the perception of a lack of human resources (HR) were also found to predict employee outcome variables. The results emphasize the impact that middle managers and HR managers can have in terms of reducing the detrimental employee effects that can be caused by the introduction of new public management (NPM) and the potential for a positive impact on employees. In particular, public-sector managers can use the design of jobs and the development of social support mechanisms, such as employee assistance programmes, to maintain, if not improve, the quality of working life experienced by their employees. More broadly, this study has found that the job strain model is a useful tool in a public-sector environment and is likely to be of increasing utility with the continuing introduction or consolidation of NPM over time. Managing these issues in the new public sector could be a key means of protecting the key resource of the Australian public sector - the employees.<br /

    The use of automatic scale selection to improve the spatial and spectral resolution of a scintillator-coupled EMCCD

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    The technology behind the Electron-Multiplying Charge Coupled Device (EMCCD) was successfully exploited by e2v technologies in the late 1990s. Since then, many uses have been found for these low light level (L3) devices including surveillance and many scientific applications. The EMCCD increases or 'multiplies' the charge signal by the phenomenon of impact ionisation (or avalanche multiplication) allowing the detection of low signal events of only a few photons. When coupled with a scintillator, this low light capability can be used to image photon flashes from individual X-ray interaction events. The combination of depth of interaction effects in the scintillator, shot noise on the signal and the multiplication noise factor lead to large variations in the profile of the detected signal from a constant energy X-ray source. This variation leads to reduced spectral performance and can have adverse effects on the centering techniques used in photon-counting imagers. The concept of scale-space is similar in many ways to the Fourier or wavelet transforms. Automatic scale selection can be implemented through the scale-space transform as a method of fitting a known profile to the observed photon flash. The process is examined here in the context of the photon-counting EMCCD detector and the results obtained in both simulated and experimental data compared. Through the analysis of the fitting process and the results achieved, the implications on imaging performance and spectral resolution are discussed

    A survey of carbon nanotube interconnects for energy efficient integrated circuits

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    This article is a review of the state-of-art carbon nanotube interconnects for Silicon application with respect to the recent literature. Amongst all the research on carbon nanotube interconnects, those discussed here cover 1) challenges with current copper interconnects, 2) process &amp; growth of carbon nanotube interconnects compatible with back-end-of-line integration, and 3) modeling and simulation for circuit-level benchmarking and performance prediction. The focus is on the evolution of carbon nanotube interconnects from the process, theoretical modeling, and experimental characterization to on-chip interconnect applications. We provide an overview of the current advancements on carbon nanotube interconnects and also regarding the prospects for designing energy efficient integrated circuits. Each selected category is presented in an accessible manner aiming to serve as a survey and informative cornerstone on carbon nanotube interconnects relevant to students and scientists belonging to a range of fields from physics, processing to circuit design

    Sleep problems among sexual minorities: a longitudinal study on the influence of the family of origin and chosen family

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    Background: There is growing evidence that lesbian, gay, and bisexual (LGB) adults experience more sleep problems than the general population. As LGB individuals experience a signifcantly greater risk of family rejection and low family support, our study investigates the role of family support as a potential determinant of LGB sleep problems over a prolonged period, and whether friend support (i.e. chosen family) can mitigate the efect of low family support. Given the importance of sleep on mental and physical health, study results may help shed light on persistent health disparities across sexual orientations. Methods: Our sample included 1703 LGB individuals from the UK Household Longitudinal Study (UKHLS). Mixed-efect logistic regressions were used to estimate the efect of family and friend support on the development of sleep problems after 24months while controlling for potential confounders. A modifed Pittsburgh Sleep Quality Index was used to measure 1) presence of any sleep problems, 2) short sleep duration, and 3) poor sleep quality. Results: Family support at baseline was independently associated with all sleep problems in our study after 24-months: 1 SD increase in family support was associated with a 0.94 times lower risk of sleep problems (95% C.I=0.90-0.98), a 0.88 times lower risk of short sleep duration (95% C.I=0.81-0.95), and a 0.92 times lower risk of sleep quality (95% C.I=0.93-0.98). Support from one’s chosen family (proxied by friend support) did not mitigate the efects of low family support on sleep problems. Conclusions: Our study found a consistent efect of family support across all sleep outcomes along with evidence of a persistent efect after 24months. Our fndings point to the importance of targeting family support in designing interventions aimed at reducing LGB sleep problems.Brock Library Open Access Publishing Fun

    Sugarcane mosaic virus infects Stenotaphrum secundatum in Australia

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    This study presents the first report of sugarcane mosaic virus (SCMV) infecting Stenotaphrum secundatum (buffalo grass) in Australia, from a turf farm in the Hunter Valley, New South Wales. The plant displayed mosaic symptoms and contained flexuous, filamentous virions of 700–750 × 10–11 nm typical of members of the genus Potyvirus. Infection of the sample by SCMV was confirmed by double antibody sandwich ELISA and RT-PCR amplification of the coat protein coding region of the viral genome. In a phylogenetic analysis, the buffalo grass isolate was sister to a clade of maize-infecting isolates of SCMV from eastern Africa and was 75.8% and 79.4% identical to the exemplar isolate of SCMV at nucleotide and amino acid levels, respectively

    Ecological engineering across organismal scales: trophic-mediated positive effects of microhabitat enhancement on fishes

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    Retrofitting microhabitat features is a common ecological engineering technique for enhancing biodiversity and abundance of small, epilithic organisms on artificial shorelines by providing refuge spaces and/or ameliorating abiotic conditions. These features are typically too small to be utilised as refugia by larger, highly motile consumers such as fish, but they may affect these organisms through other mechanisms. This study sought to determine whether microhabitat enhancement units alter the fish abundance, richness and assemblage composition on tropical seawalls and explores possible underlying trophic mechanisms. We created 12 experimental plots consisting of 6 enhanced plots, each with 20 microhabitat enhancement tiles, and 6 control plots without tiles on intertidal seawalls at Pulau Hantu, an offshore island south of mainland Singapore. Benthic cover and fish assemblage were surveyed within each plot using photoquadrats and underwater video cameras, respectively, from April 2018 to February 2019. We found greater abundance and species richness and distinct assemblages of fish in the enhanced plots compared to the control plots. These differences were driven largely by an increase in both abundance and richness of fish species with epibenthic-feeding strategies and were significantly associated with higher biotic cover in the enhanced plots, especially epilithic algal matrix (EAM). Our results indicate that, in addition to facilitating epilithic organisms, microhabitat enhancement can provide food resources for epibenthic-feeding fishes, increase fish biodiversity, and alter fish assemblages in tropical urbanised shorelines
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