9,770 research outputs found

    A quantum electron star

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    We construct and probe a holographic description of state of matter which results from coupling a Fermi liquid to a relativistic conformal field theory (CFT). The bulk solution is described by a quantum gas of fermions supported from collapse into the gravitational well of AdS by their own electrostatic repulsion. In the probe limit studied here, the Landau quasiparticles survive this coupling to a CFT.Comment: 8 pages, 7 figure

    A quasi-time-dependent radiative transfer model of OH104.9+2.4

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    We investigate the pulsation-phase dependent properties of the circumstellar dust shell (CDS) of the OH/IR star OH104.9+2.4 based on radiative transfer modeling (RTM) using the code DUSTY. Our previous study concerning simultaneous modeling of the spectral energy distribution (SED) and near-infrared (NIR) visibilities (Riechers et al. 2004) has now been extended by means of a more detailed analysis of the pulsation-phase dependence of the model parameters of OH104.9+2.4. In order to investigate the temporal variation in the spatial structure of the CDS, additional NIR speckle interferometric observations in the K' band were carried out with the 6 m telescope of the Special Astrophysical Observatory (SAO). At a wavelength of 2.12 micron the diffraction-limited resolution of 74 mas was attained. Several key parameters of our previous best-fitting model had to be adjusted in order to be consistent with the newly extended amount of observational data. It was found that a simple rescaling of the bolometric flux F_bol is not sufficient to take the variability of the source into account, as the change in optical depth over a full pulsation cycle is rather high. On the other hand, the impact of a change in effective temperature T_eff on SED and visibility is rather small. However, observations, as well as models for other AGB stars, show the necessity of including a variation of T_eff with pulsation phase in the radiative transfer models. Therefore, our new best-fitting model accounts for these changes.Comment: 7 pages, including 5 postscript figures and 3 tables. Published in Astronomy and Astrophysics. (v1: accepted version; v2: published version, minor grammatical changes

    Uptake of Virtual Visits in A Geriatric Primary Care Clinic During the COVID‐19 Pandemic

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156159/2/jgs16534.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156159/1/jgs16534_am.pd

    Boiling the Frog Slowly:The Immersion of C-Suite Financial Executives into Fraud

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    This study explores how financial executives retrospectively account for their crossing the line into financial statement fraud while acting within or reacting to a financialized corporate environment. We conduct our investigation through face-to-face interviews with 13 former C-suite financial executives who were involved in and indicted for major cases of accounting fraud. Five different themes of accounts emerged from the narratives, characterizing executives' fraud immersion as a meaning-making process by which the particulars of the proximal social context (the influence of social actors and contextual characteristics) and individual motivations collectively molded executives' vocabularies of fraud immersion. Our executives' narratives portray their fraud entanglement as typically occurring in small, incremental steps. Their accounts expand our understanding of the influence of socialization on executive-level financial fraud beyond the individualized focus of the fraud triangle model

    Why do some sex chromosomes degenerate more slowly than others? The odd case of ratite sex chromosomes

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    The hallmark of sex chromosome evolution is the progressive suppression of recombination which leads to subsequent degeneration of the non-recombining chromosome. In birds, species belonging to the two major clades, Palaeognathae (including tinamous and flightless ratites) and Neognathae (all remaining birds), show distinctive patterns of sex chromosome degeneration. Birds are female heterogametic, in which females have a Z and a W chromosome. In Neognathae, the highly-degenerated W chromosome seems to have followed the expected trajectory of sex chromosome evolution. In contrast, among Palaeognathae, sex chromosomes of ratite birds are largely recombining. The underlying reason for maintenance of recombination between sex chromosomes in ratites is not clear. Degeneration of the W chromosome might have halted or slowed down due to a multitude of reasons ranging from selective processes, such as a less pronounced effect of sexually antagonistic selection, to neutral processes, such as a slower rate of molecular evolution in ratites. The production of genome assemblies and gene expression data for species of Palaeognathae has made it possible, during recent years, to have a closer look at their sex chromosome evolution. Here, we critically evaluate the understanding of the maintenance of recombination in ratites in light of the current data. We conclude by highlighting certain aspects of sex chromosome evolution in ratites that require further research and can potentially increase power for the inference of the unique history of sex chromosome evolution in this lineage of birds
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