8,307 research outputs found

    How should we interpret the two transport relaxation times in the cuprates ?

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    We observe that the appearance of two transport relaxation times in the various transport coefficients of cuprate metals may be understood in terms of scattering processes that discriminate between currents that are even, or odd under the charge conjugation operator. We develop a transport equation that illustrates these ideas and discuss its experimental and theoretical consequences.Comment: 19 pages, RevTeX with 8 postscript figures included. To appear in ``Non Fermi Liquid Physics'', J. Phys:Cond. Matt. (1997

    Electron spin relaxation in organic semiconductors probed through muSR

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    Muon spin spectroscopy and in particular the avoided level crossing technique is introduced, with the aim of showing it as a very sensitive local probe for electron spin relaxation in organic semiconductors. Avoided level crossing data on TMS-pentacene at different temperatures are presented, and they are analysed to extract the electron spin relaxation rate, that is shown to increase on increasing the temperature from 0.02 MHz to 0.33 MHz at 3 K and 300 K respectively.Comment: International Conference TSN2010 "Trends in spintronics and nanomagnetism

    Singular value decomposition applied to compact binary coalescence gravitational-wave signals

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    We investigate the application of the singular value decomposition to compact-binary, gravitational-wave data-analysis. We find that the truncated singular value decomposition reduces the number of filters required to analyze a given region of parameter space of compact binary coalescence waveforms by an order of magnitude with high reconstruction accuracy. We also compute an analytic expression for the expected signal-loss due to the singular value decomposition truncation.Comment: 4 figures, 6 page

    An Analysis of ALMA Deep Fields and the Perceived Dearth of High-z Galaxies

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    Deep, pencil-beam surveys from ALMA at 1.1-1.3mm have uncovered an apparent absence of high-redshift dusty galaxies, with existing redshift distributions peaking around z1.52.5z\sim1.5-2.5. This has led to a perceived dearth of dusty systems at z>4z>4, and the conclusion, according to some models, that the early Universe was relatively dust-poor. In this paper, we extend the backward evolution galaxy model described by Casey et al. (2018) to the ALMA regime (in depth and area) and determine that the measured number counts and redshift distributions from ALMA deep field surveys are fully consistent with constraints of the infrared luminosity function (IRLF) at z<2.5z<2.5 determined by single-dish submillimeter and millimeter surveys conducted on much larger angular scales (110\sim1-10deg2^{2}). We find that measured 1.1-1.3mm number counts are most constraining for the measurement of the faint-end slope of the IRLF at z4z4. Recent studies have suggested that UV-selected galaxies at z>4z>4 may be particularly dust-poor, but we find their millimeter-wave emission cannot rule out consistency with the Calzetti dust attenuation law even by assuming relatively typical, cold-dust (Tdust30T_{\rm dust}\approx30\,K) SEDs. Our models suggest that the design of ALMA deep fields requires substantial revision to constrain the prevalence of z>4z>4 early Universe obscured starbursts. The most promising avenue for detection and characterization of such early dusty galaxies will come from future ALMA 2mm blank field surveys covering a few hundred arcmin2^{2} and the combination of existing and future dual-purpose 3mm datasets.Comment: 21 pages, 12 figures, accepted for publication in Ap

    Patient Deception in Health Care: Physical Therapy Education, Beliefs, and Attitudes

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    A good professional-patient relationship is important to clinical practice, which may be compromised by deception. Deception research in physical therapy is scant. The current study investigated how the topic of patient deception is addressed in Doctor of Physical Therapy (DPT) educational curriculum, explore DPT students’ beliefs about deception and attitudes toward patient deception, and examine the effects of a pedagogical intervention on DPT students’ beliefs about deception and attitudes toward patient deception. The first objective was pursued by a descriptive survey sent to 217 DPT programs in the US. The second and third objectives were achieved by one-group pretest-posttest design provided to 17 DPT students before and after an educational workshop. Most DPT programs minimally include the topic of patient deception within their curriculum. DPT students held several inaccurate beliefs about the indicators of deception and negative attitudes toward patients who lied. After the educational intervention, students’ inaccurate beliefs were corrected and negative attitudes were reduced. Patient deception seems to be an under-addressed topic in current physical therapy education. An education workshop improved students’ beliefs about deception and attitudes toward to patient deception. Implications of deception research and theory in the applied practice of physical therapy are discussed

    Quantifying the Human Impacts on Papua New Guinea Reef Fish Communities across Space and Time

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    Describing the drivers of species loss and of community change are important goals in both conservation and ecology. However, it is difficult to determine whether exploited species decline due to direct effects of harvesting or due to other environmental perturbations brought about by proximity to human populations. Here we quantify differences in species richness of coral reef fish communities along a human population gradient in Papua New Guinea to understand the relative impacts of fishing and environmental perturbation. Using data from published species lists we categorize the reef fishes as either fished or non-fished based on their body size and reports from the published literature. Species diversity for both fished and non-fished groups decreases as the size of the local human population increases, and this relationship is stronger in species that are fished. Additionally, comparison of modern and museum collections show that modern reef communities have proportionally fewer fished species relative to 19th century ones. Together these findings show that the reef fish communities of Papua New Guinea experience multiple anthropogenic stressors and that even at low human population levels targeted species experience population declines across both time and space

    Cooperativity and Frustration in Protein-Mediated Parallel Actin Bundles

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    We examine the mechanism of bundling of cytoskeletal actin filaments by two representative bundling proteins, fascin and espin. Small-angle X-ray studies show that increased binding from linkers drives a systematic \textit{overtwist} of actin filaments from their native state, which occurs in a linker-dependent fashion. Fascin bundles actin into a continuous spectrum of intermediate twist states, while espin only allows for untwisted actin filaments and fully-overtwisted bundles. Based on a coarse-grained, statistical model of protein binding, we show that the interplay between binding geometry and the intrinsic \textit{flexibility} of linkers mediates cooperative binding in the bundle. We attribute the respective continuous/discontinous bundling mechanisms of fascin/espin to differences in the stiffness of linker bonds themselves.Comment: 5 pages, 3 figures, figure file has been corrected in v

    Mid-infrared Hall effect in thin-film metals: Probing the Fermi surface anisotropy in Au and Cu

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    A sensitive mid-infrared (MIR, 900-1100 cm-1, 112-136 meV) photo-elastic polarization modulation technique is used to measure simultaneously Faraday rotation and circular dichroism in thin metal films. These two quantities determine the complex AC Hall conductivity. This novel technique is applied to study Au and Cu thin films at temperatures down to 20 K and magnetic fields up to 8 T. The Hall frequency is consistent with band theory predictions. We report the first measurement of the MIR Hall scattering rate, which is significantly lower than that derived from Drude analysis of zero magnetic field MIR transmission measurements. This difference is qualitatively explained in terms of the anisotropy of the Fermi surface in Au and Cu.Comment: 14 pages of text, 5 figure
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