4,293 research outputs found

    Black Hole Monodromy and Conformal Field Theory

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    The analytic structure of solutions to the Klein-Gordon equation in a black hole background, as represented by monodromy data, is intimately related to black hole thermodynamics. It encodes the "hidden conformal symmetry" of a non-extremal black hole, and it explains why features of the inner event horizon appear in scattering data such as greybody factors. This indicates that hidden conformal symmetry is generic within a universality class of black holes.Comment: 20 pages, v2 minor corrections, updated reference

    Taxes and Time Allocation: Evidence from Single Women

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    Hundreds of papers have investigated how incentives and policies affect hours worked in the market. This paper examines how income taxes affect time allocation in the other two-thirds of the day. Using the Panel Study of Income Dynamics from 1975 to 2004, we analyze the response of single women's housework, labor supply, and other time to variation in tax and transfer schedules across income levels, number of children, states, and time. We find that when the economic reward to participating in the labor force increases, market work increases and housework decreases, with the decrease in housework accounting for approximately two-thirds of the increase in market work. Analysis of repeated cross-sections of time diary data from 1975 to 2004 shows that changes in "home production" account for at least half of the increase in market hours of work in response to policy changes. Data on expenditures from the Consumer Expenditure Survey from 1980 to 2003 show some evidence that expenditures on market goods likely to substitute for housework increase in response to a greater incentive to join the labor force. The baseline estimates imply that the elasticity of substitution between consumption of home and market goods is 2.43. The results are consistent with the classic time allocation model of Becker (1965).

    Raw and Count Data Comparability of Hip-Worn ActiGraph GT3X+ and Link Accelerometers

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    To enable inter- and intrastudy comparisons it is important to ascertain comparability among accelerometer models. Purpose: The purpose of this study was to compare raw and count data between hip-worn ActiGraph GT3X+ and GT9X Link accelerometers. Methods: Adults (n = 26 (n = 15 women); age, 49.1 T 20.0 yr) wore GT3X+ and Link accelerometers over the right hip for an 80-min protocol involving 12–21 sedentary, household, and ambulatory/exercise activities lasting 2–15 min each. For each accelerometer, mean and variance of the raw (60 Hz) data for each axis and vector magnitude (VM) were extracted in 30-s epochs. A machine learning model (Montoye 2015) was used to predict energy expenditure in METs from the raw data. Raw data were also processed into activity counts in 30-s epochs for each axis and VM, with Freedson 1998 and 2011 count-based regression models used to predictMETs. Time spent in sedentary, light, moderate, and vigorous intensities was derived from predicted METs from each model. Correlations were calculated to compare raw and count data between accelerometers, and percent agreement was used to compare epoch-by-epoch activity intensity. Results: For raw data, correlations for mean acceleration were 0.96 T 0.05, 0.89 T 0.16, 0.71 T 0.33, and 0.80 T 0.28, and those for variance were 0.98 T 0.02, 0.98 T 0.03, 0.91 T 0.06, and 1.00 T 0.00 in the X, Y, and Z axes and VM, respectively. For count data, corresponding correlations were 1.00 T 0.01, 0.98 T 0.02, 0.96 T 0.04, and 1.00 T 0.00, respectively. Freedson 1998 and 2011 count-based models had significantly higher percent agreement for activity intensity (95.1% T 5.6% and 95.5% T 4.0%) compared with theMontoye 2015 raw data model (61.5% T 27.6%; P G 0.001). Conclusions: Count data were more highly comparable than raw data between accelerometers. Data filtering and/or more robust raw data models are needed to improve raw data comparability between ActiGraph GT3X+ and Link accelerometers

    Influence of impurity spin dynamics on quantum transport in epitaxial graphene

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    Experimental evidence from both spin-valve and quantum transport measurements points towards unexpectedly fast spin relaxation in graphene. We report magnetotransport studies of epitaxial graphene on SiC in a vector magnetic field showing that spin relaxation, detected using weak-localisation analysis, is suppressed by an in-plane magnetic field, BB_{\parallel}, and thereby proving that it is caused at least in part by spinful scatterers. A non-monotonic dependence of effective decoherence rate on BB_{\parallel} reveals the intricate role of scatterers' spin dynamics in forming the interference correction to conductivity, an effect that has gone unnoticed in earlier weak localisation studie

    Impairment of the CD8+ T cell response in lungs following infection with human respiratory syncytial virus is specific to the anatomical site rather than the virus, antigen, or route of infection

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    <p>Abstract</p> <p>Background</p> <p>A subset of the virus-specific CD8+ cytotoxic T lymphocytes (CTL) isolated from the lungs of mice infected with human respiratory syncytial virus (RSV) is impaired in the ability to secrete interferon γ (IFNγ), a measure of functionality. It was suggested that the impairment specifically suppressed the host cellular immune response, a finding that could help explain the ability of RSV to re-infect throughout life.</p> <p>Results</p> <p>To determine whether this effect is dependent on the virus, the route of infection, or the type of infection (respiratory, disseminated, or localized dermal), we compared the CTL responses in mice following intranasal (IN) infection with RSV or influenza virus or IN or intradermal (ID) infection with vaccinia virus expressing an RSV CTL antigen. The impairment was observed in the lungs after IN infection with RSV, influenza or vaccinia virus, and after a localized ID infection with vaccinia virus. In contrast, we observed a much higher percentage of IFNγ secreting CD8+ lymphocytes in the spleens of infected mice in every case.</p> <p>Conclusion</p> <p>The decreased functionality of CD8+ CTL is specific to the lungs and is not dependent on the specific virus, viral antigen, or route of infection.</p
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