247 research outputs found

    A rotating three component perfect fluid source and its junction with empty space-time

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    The Kerr solution for empty space-time is presented in an ellipsoidally symmetric coordinate system and it is used to produce generalised ellipsoidal metrics appropriate for the generation of rotating interior solutions of Einstein's equations. It is shown that these solutions are the familiar static perfect fluid cases commonly derived in curvature coordinates but now endowed with rotation. The resulting solutions are also discussed in the context of T-solutions of Einstein's equations and the vacuum T-solution outside a rotating source is presented. The interior source for these solutions is shown not to be a perfect fluid but rather an anisotropic three component perfect fluid for which the energy momentum tensor is derived. The Schwarzschild interior solution is given as an example of the approach.Comment: 14 page

    Measuring Black Hole Spin using X-ray Reflection Spectroscopy

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    I review the current status of X-ray reflection (a.k.a. broad iron line) based black hole spin measurements. This is a powerful technique that allows us to measure robust black hole spins across the mass range, from the stellar-mass black holes in X-ray binaries to the supermassive black holes in active galactic nuclei. After describing the basic assumptions of this approach, I lay out the detailed methodology focusing on "best practices" that have been found necessary to obtain robust results. Reflecting my own biases, this review is slanted towards a discussion of supermassive black hole (SMBH) spin in active galactic nuclei (AGN). Pulling together all of the available XMM-Newton and Suzaku results from the literature that satisfy objective quality control criteria, it is clear that a large fraction of SMBHs are rapidly-spinning, although there are tentative hints of a more slowly spinning population at high (M>5*10^7Msun) and low (M<2*10^6Msun) mass. I also engage in a brief review of the spins of stellar-mass black holes in X-ray binaries. In general, reflection-based and continuum-fitting based spin measures are in agreement, although there remain two objects (GROJ1655-40 and 4U1543-475) for which that is not true. I end this review by discussing the exciting frontier of relativistic reverberation, particularly the discovery of broad iron line reverberation in XMM-Newton data for the Seyfert galaxies NGC4151, NGC7314 and MCG-5-23-16. As well as confirming the basic paradigm of relativistic disk reflection, this detection of reverberation demonstrates that future large-area X-ray observatories such as LOFT will make tremendous progress in studies of strong gravity using relativistic reverberation in AGN.Comment: 19 pages. To appear in proceedings of the ISSI-Bern workshop on "The Physics of Accretion onto Black Holes" (8-12 Oct 2012). Revised version adds a missing source to Table 1 and Fig.6 (IRAS13224-3809) and corrects the referencing of the discovery of soft lags in 1H0707-495 (which were in fact first reported in Fabian et al. 2009

    Stereotype priming in face recognition: interactions between semantic and visual information in face encoding

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    The accuracy with which previously unfamiliar faces are recognised is increased by the presentation of a stereotype-congruent occupation label (Klatzky, Martin, & Kane, 1982a, b). For example, providing the label ‘criminal’ both during encoding and test improves recognition for previously unfamiliar faces that look like the stereotypical criminal. Experiments 1 and 2 both replicate this effect and show that the label exerts its influence during the encoding of stereotypical faces and has little influence at test. These findings indicate that semantic information that is congruent with novel stereotypical faces facilitates their encoding

    Simulation of alcohol control policies for health equity (SIMAH) project: study design and first results

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    Since about 2010, life expectancy at birth in the United States has stagnated and begun to decline, with concurrent increases in the socioeconomic divide in life expectancy. The Simulation of Alcohol Control Policies for Health Equity (SIMAH) Project uses a novel microsimulation approach to investigate the extent to which alcohol use, socioeconomic status (SES), and race/ethnicity contribute to unequal developments in US life expectancy and how alcohol control interventions could reduce such inequalities. Representative, secondary data from several sources will be integrated into one coherent, dynamic microsimulation to model life-course changes in SES and alcohol use and cause-specific mortality attributable to alcohol use by SES, race/ethnicity, age, and sex. Markov models will be used to inform transition intensities between levels of SES and drinking patterns. The model will be used to compare a baseline scenario with multiple counterfactual intervention scenarios. The preliminary results indicate that the crucial microsimulation component provides a good fit to observed demographic changes in the population, providing a robust baseline model for further simulation work. By demonstrating the feasibility of this novel approach, the SIMAH Project promises to offer superior integration of relevant empirical evidence to inform public health policy for a more equitable future

    The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US high school boys' ice hockey (2008-2009 through 2013-2014) and National Collegiate Athletic Association men's and women's ice hockey (2004-2005 through 2013-2014)

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    Context: Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided efforts to collect data on ice hockey injuries. Objective: To describe the epidemiology of injuries sustained in high school boy's ice hockey in the 2008-2009 through 2013-2014 academic years and collegiate men's and women's ice hockey in the 2004-2005 through 2013-2014 academic years using Web-based surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance of ice hockey teams of high school boys (annual average ¼ 34), collegiate men (annual average ¼ 20), and collegiate women (annual average ¼ 11). Patients or Other Participants: Boys', men's, and women's ice hockey players who participated in practices and competitions during the 2008-2009 through 2013-2014 high school academic years or the 2004-2005 through 2013-2014 collegiate academic years. Main Outcome Measure(s): Athletic trainers collected time-loss (24 hours) injury and exposure data. We calculated injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis. Results: The High School Reporting Information Online system documented 831 boys' ice hockey time-loss injuries during 356 997 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 2611 men's ice hockey time-loss injuries during 552 642 AEs and 752 women's ice hockey injuries during 232 051 AEs. Injury rates were higher in collegiate men than in high school boys during 2008-2009 through 2013-2014 (4.38 versus 2.33/1000 AEs; IRR ¼ 1.88; 95% CI ¼ 1.73, 2.05) and collegiate women during 2004-2005 through 2013-2014 (IRR ¼ 1.46; 95% CI ¼ 1.34, 1.58). Most injuries occurred during competitions (boys ¼ 80.0%, men ¼ 66.9%, women ¼ 55.3%); injury rates were higher in competitions than in practices for boys (IRR ¼ 8.14; 95% CI ¼ 6.87, 9.65), men (IRR ¼ 6.58; 95% CI ¼ 6.06, 7.13), and women (IRR ¼ 3.63; 95% CI ¼ 3.14, 4.19). At all levels, most injuries occurred to the head/face and shoulder/clavicle and resulted in concussions, contusions, or ligament sprains. Conclusions: Injury rates varied across sports but were consistently higher in competitions than in practices. In competitions, concussions were common injuries, highlighting the need for continued development of injury-prevention strategies

    Large-scale pharmacogenomic study of sulfonylureas and the QT, JT and QRS intervals: CHARGE Pharmacogenomics Working Group

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    Sulfonylureas, a commonly used class of medication used to treat type 2 diabetes, have been associated with an increased risk of cardiovascular disease. Their effects on QT interval duration and related electrocardiographic phenotypes are potential mechanisms for this adverse effect. In 11 ethnically diverse cohorts that included 71 857 European, African-American and Hispanic/Latino ancestry individuals with repeated measures of medication use and electrocardiogram (ECG) measurements, we conducted a pharmacogenomic genome-wide association study of sulfonylurea use and three ECG phenotypes: QT, JT and QRS intervals. In ancestry-specific meta-analyses, eight novel pharmacogenomic loci met the threshold for genome-wide significance (P&lt;5 × 10−8), and a pharmacokinetic variant in CYP2C9 (rs1057910) that has been associated with sulfonylurea-related treatment effects and other adverse drug reactions in previous studies was replicated. Additional research is needed to replicate the novel findings and to understand their biological basis

    The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US High School Girls' Field Hockey (2008-2009 Through 2013-2014) and National collegiate athletic association women's field hockey (2004-2005 through 2013-2014)

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    Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of data for girls' and women's field hockey injuries. Objective: To describe the epidemiology of injuries sustained in high school girls' field hockey in the 2008-2009 through 2013-2014 academic years and collegiate women's field hockey in the 2004-2005 through 2013-2014 academic years using Web-based sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from field hockey teams in high school girls (annual average=61) and collegiate women (annual average = 14). Patients or Other Participants: Girls' and women's field hockey players who participated in practices and competitions during the 2008-2009 through 2013-2014 high school academic years and the 2004-2005 through 2013-2014 collegiate academic years. Main Outcome Measure(s): Athletic trainers collected timeloss (≥24 hours) injury and exposure data. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis were calculated. Results: The High School Reporting Information Online system documented 983 time-loss injuries during 569 551 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 996 time-loss injuries during 185 984 AEs. The injury rate from 2008-2009 through 2013-2014 was higher in college than in high school (3.25 versus 1.73/1000 AEs; IRR= 1.89; 95% CI = 1.63, 2.18). Most injuries occurred during practices in high school (52.0%) and college (60.7%). Injury rates were higher during competitions than practices in high school (IRR = 2.00; 95% CI = 1.76, 2.26) and college (IRR = 1.96; 95% CI = 1.73, 2.23). At both levels, injuries most commonly occurred to the lower extremity and head/face and resulted in muscle/tendon strains and contusions. However, injury patterns varied between practices and competitions. Conclusions: Injury rates and patterns varied across age groups and between practices and competitions, highlighting the need for development of targeted injury-prevention strategies at both levels of play

    Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares

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    The extreme ultraviolet portion of the solar spectrum contains a wealth of diagnostic tools for probing the lower solar atmosphere in response to an injection of energy, particularly during the impulsive phase of solar flares. These include temperature and density sensitive line ratios, Doppler shifted emission lines and nonthermal broadening, abundance measurements, differential emission measure profiles, and continuum temperatures and energetics, among others. In this paper I shall review some of the advances made in recent years using these techniques, focusing primarily on studies that have utilized data from Hinode/EIS and SDO/EVE, while also providing some historical background and a summary of future spectroscopic instrumentation.Comment: 34 pages, 8 figures. Submitted to Solar Physics as part of the Topical Issue on Solar and Stellar Flare

    Introducing CASCADEPOP: an open-source sociodemographic simulation platform for US health policy appraisal

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    Largescale individual-level and agent-based models are gaining importance in health policy appraisal and evaluation. Such models require the accurate depiction of the jurisdiction’s population over extended time periods to enable modeling of the development of non-communicable diseases under consideration of historical, sociodemographic developments. We developed CASCADEPOP to provide a readily available sociodemographic micro-synthesis and microsimulation platform for US populations. The micro-synthesis method used iterative proportional fitting to integrate data from the US Census, the American Community Survey, the Panel Study of Income Dynamics, Multiple Cause of Death Files, and several national surveys to produce a synthetic population aged 12 to 80 years on 01/01/1980 for five states (California, Minnesota, New York, Tennessee, and Texas) and the US. Characteristics include individuals’ age, sex, race/ethnicity, marital/employment/parental status, education, income and patterns of alcohol use as an exemplar health behavior. The microsimulation simulates individuals’ sociodemographic life trajectories over 35 years to 31/12/2015 accounting for population developments including births, deaths, and migration. Results comparing the 1980 micro-synthesis against observed data shows a successful depiction of state and US population characteristics and of drinking. Comparing the microsimulation over 30 years with Census data also showed the successful simulation of sociodemographic developments. The CASCADEPOP platform enables modelling of health behaviors across individuals’ life courses and at a population level. As it contains a large number of relevant sociodemographic characteristics it can be further developed by researchers to build US agent-based models and microsimulations to examine health behaviors, interventions, and policies
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