1,436 research outputs found

    The Insignificance of Global Reheating in the Abell 1068 Cluster: X-Ray Analysis

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    We report on a Chandra observation of the massive, medium redshift (z=0.1386) cooling flow cluster Abell 1068. We detect a clear temperature gradient in the X-ray emitting gas from kT ~ 5 keV in the outer part of the cluster down to roughly 2 keV in the core, and a striking increase in the metallicity of the gas toward the cluster center. The total spectrum from the cluster can be fit by a cooling flow model with a total mass deposition rate of 150 solar masses/yr. Within the core (r < 30 kpc), the mass depositon rate of 40 solar masses/yr is comparable to estimates for the star formation rate from optical data. We find an apparent correlation between the cD galaxy's optical isophotes and enhanced metallicity isocontours in the central ~100 kpc of the cluster. We show that the approximate doubling of the metallicity associated with the cD can be plausibly explained by supernova explosions associated with the cD's ambient stellar population and the recent starburst. Finally, we calculate the amount of heating due to thermal conduction and show that this process is unlikely to offset cooling in Abell 1068.Comment: Accepted for publication in ApJ, 26 pages, 12 b+w figures, 3 color figure

    Comparative Effectiveness of Step-up Therapies in Children with Asthma Prescribed Inhaled Corticosteroids : A Historical Cohort Study

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    This work was supported by the Respiratory Effectiveness Group. Acknowledgments We thank the Respiratory Effectiveness Group for funding this work, Annie Burden for assistance with statistics, and Simon Van Rysewyk and Lisa Law for assistance with medical writing.Peer reviewedPostprin

    Comparison of equations for the calculation of LDL-cholesterol in hospitalized patients

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    BACKGROUND : The Friedewald equation is widely used to calculate LDL-C for cardiovascular risk prediction but is less accurate with comorbidities and extreme lipid values. Several novel formulae have been reported to outperform the Friedewald formula. METHODS : We examined 14,219 lipid profiles and evaluated four formulae (Friedewald, Chen, de Cordova, Hattori) and compared these to direct measurement of LDL-C across various triglyceride (TG), total cholesterol (TC) and HDL-cholesterol (HDL-C) ranges using Beckman reagents and instruments. Linear regression and ROC analysis were performed. RESULTS : The de Cordova formula showed a high correlation with directly measured LDL-C (r= 0.90, P b 0.001), comparable to the Friedewald calculated values for directly measured LDL-C (r = 0.95, P b 0.001). The de Cordova formula was favorable in some ranges of HDL, TC and the lowest TG range (r = 0.97, P b 0.001) but performed least well in comparison with the three other LDL-C calculations (AUC=0.8331), demonstrating inconsistent bias. The Chen formula performed better than Friedewald (AUC = 0.9049). The Hattori formula outperformed all formulae including Friedewald over various ranges of lipid values (AUC= 0.9097). CONCLUSIONS : We observe favorable correlations of the de Cordova formula with Friedewald at low TG values. However, the Hattori formula appears to be best for application in hospitalized patients, even at extreme lipid values.http://www.elsevier.com/locate/clinchim2016-04-30hb201

    A real-life comparative effectiveness study into the addition of antibiotics to the management of asthma exacerbations in primary care

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    Acknowledgements: This project was supported by the Respiratory Effectiveness Group. Data and data management support was provided in-kind by Optimum Patient Care (www.opcrd.co.uk) and Derek Skinner at OPC. Clare Murray is supported by the NIHR Manchester Biomedical Research Centre.Peer reviewedPostprin

    Mirror coating solution for the cryogenic Einstein telescope

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    Planned, cryogenic gravitational-wave detectors will require improved coatings with a strain thermal noise reduced by a factor of 25 compared to Advanced LIGO. In this article, we present investigations of HfO2 doped with SiO2 as a new coating material for future detectors. Our measurements show an extinction coefficient of k=6×10−6 and a mechanical loss of ϕ=3.8×10−4 at 10,K, which is a factor of 2 below that of SiO2, the currently used low refractive-index coating material. These properties make HfO2 doped with SiO2 ideally suited as a low-index partner material for use with a-Si in the lower part of a multimaterial coating. Based on these results we present a multimaterial coating design which, for the first time, can simultaneously meet the strict requirements on optical absorption and thermal noise of the cryogenic Einstein Telescope

    Geological imprint of methane seepage on the seabed and biota of the convergent Hikurangi Margin, New Zealand: box core and grab carbonate results

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    Short box cores (to 30 cm bsf) and seafloor carbonate grab samples were acquired at mapped hydrocarbon seep sites (600–1200 m water depths) during the 2007 RV SONNE SO191 cruise on the Hikurangi Margin offshore eastern North Island, New Zealand, to evaluate the influence of methane seepage on sedimentologic, biotic, mineralogic and stable isotopic attributes of seabed sediments. Sedimentary horizons in the box cores consist of siliciclastic silts and sands, shell beds and nodular, microcrystalline aragonite bands up to 15 cm thick. The megafauna is dominated by infaunal to semi-infaunal chemosymbiotic bivalves (Calyptogena, Lucinoma, and Acharax), as well as associated worms and carnivorous and grazing gastropods. Burrows in silts, some occupied by worms or juvenile Acharax, mainly have simple morphologies more typical of high-energy, nearshore settings than deep-sea environments, while a few are large and sparsely branched with wall scratch marks inferred to be of decapod crustacean origin. The box core silts and nodular carbonate samples vary in TOC content from 0.2 to 0.9 wt.%, carbonate content from 4 to 78%, and δ13C and δ18O values from − 50.3 to − 0.6‰ PDB and + 0.77 to + 3.2‰ PDB, respectively. Low carbonate content silt samples have the most enriched δ13C values, implying a seawater source for their pore water bicarbonate. Negative δ13C and positive δ18O values typify the nodular, microcrystalline aragonite bands, indicating formation during microbially mediated, sulphate-dependent anaerobic oxidation of methane (AOM) in a cold, near-seafloor environment, as is also supported by lipid biomarker data. A clear isotopic mixing trend of decreasing δ13C and increasing δ18O and carbonate content in the fine (< 100 µm) carbonate fraction of the host silts also has been reported from other methane seep provinces, and suggests a heterogeneous influx of methane-rich see

    The Evolution of the Star Formation Rate of Galaxies at 0.0 < z < 1.2

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    We present the 24 micron rest-frame luminosity function (LF) of star-forming galaxies in the redshift range 0.0 < z < 0.6 constructed from 4047 spectroscopic redshifts from the AGN and Galaxy Evolution Survey of 24 micron selected sources in the Bootes field of the NOAO Deep Wide-Field Survey. This sample provides the best available combination of large area (9 deg^2), depth, and statistically complete spectroscopic observations, allowing us to probe the evolution of the 24 micron LF of galaxies at low and intermediate redshifts while minimizing the effects of cosmic variance. In order to use the observed 24 micron luminosity as a tracer for star formation, active galactic nuclei (AGNs) that could contribute significantly at 24 micron are identified and excluded from our star-forming galaxy sample based on their mid-IR spectral energy distributions or the detection of X-ray emission. The evolution of the 24 micron LF of star-forming galaxies for redshifts of z < 0.65 is consistent with a pure luminosity evolution where the characteristic 24 micron luminosity evolves as (1+z)^(3.8+/-0.3). We extend our evolutionary study to encompass 0.0 < z < 1.2 by combining our data with that of the Far-Infrared Deep Extragalactic Legacy Survey. Over this entire redshift range the evolution of the characteristic 24 micron luminosity is described by a slightly shallower power law of (1+z)^(3.4+/-0.2). We find a local star formation rate density of (1.09+/-0.21) x 10^-2 Msun/yr/Mpc^-3, and that it evolves as (1+z)^(3.5+/-0.2) over 0.0 < z < 1.2. These estimates are in good agreement with the rates using optical and UV fluxes corrected for the effects of intrinsic extinction in the observed sources. This agreement confirms that star formation at z <~ 1.2 is robustly traced by 24 micron observations and that it largely occurs in obscured regions of galaxies. (Abridged)Comment: ApJ, in press, 16 pages 9 figure

    Original Climax Films: historicizing the British hardcore pornography film business

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    This article presents findings from my research into the British hardcore pornography business. Porn studies has given little coverage to the British pornography business, with much of the academic literature focusing on the American adult entertainment industry. Recently, there has been a rising interest in the historical framework of porn cinemas both in popular culture and in academic work. This article contributes to this debate, taking both a cultural and an economic approach to explore the conditions that led to the emergence of British hardcore production as an alternative economy in the 1960s. In this economy, entrepreneurs make use of new technologies to produce artefacts that are exchanged for an economic benefit, while circumventing laws to distribute their artefacts. To historicize this economy, I draw on ethnohistorical research, which includes interviews with people involved in the British hardcore business and archival research. I argue that a combination of glamour filmmaking, a relaxation of political and cultural attitudes towards sexuality, the location of Soho, London, and emerging technologies for producing films collectively contribute to the emergence of an alternative economy of British hardcore production. I focus specifically on the practices of two entrepreneurs within this economy, Ivor Cook and Mike Freeman, considering how their actions inadvertently created the British hardcore film business, and played a significant role in the development of hardcore production outside of the United Kingdom

    Is demography destiny? Application of machine learning techniques to accurately predict population health outcomes from a minimal demographic dataset

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    © 2015 Luo et al. For years, we have relied on population surveys to keep track of regional public health statistics, including the prevalence of non-communicable diseases. Because of the cost and limitations of such surveys, we often do not have the up-to-date data on health outcomes of a region. In this paper, we examined the feasibility of inferring regional health outcomes from socio-demographic data that are widely available and timely updated through national censuses and community surveys. Using data for 50 American states (excluding Washington DC) from 2007 to 2012, we constructed a machine-learning model to predict the prevalence of six non-communicable disease (NCD) outcomes (four NCDs and two major clinical risk factors), based on population socio-demographic characteristics from the American Community Survey. We found that regional prevalence estimates for non-communicable diseases can be reasonably predicted. The predictions were highly correlated with the observed data, in both the states included in the derivation model (median correlation 0.88) and those excluded from the development for use as a completely separated validation sample (median correlation 0.85), demonstrating that the model had sufficient external validity to make good predictions, based on demographics alone, for areas not included in the model development. This highlights both the utility of this sophisticated approach to model development, and the vital importance of simple socio-demographic characteristics as both indicators and determinants of chronic disease

    Quantitative association tests of immune responses to antigens of Mycobacterium tuberculosis: a study of twins in West Africa.

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    There is now considerable evidence that host genetic factors are important in determining the outcome of infection with Mycobacterium tuberculosis (MTB). The aim of this study was to assess the role of several candidate genes in the variation observed in the immune responses to MTB antigens. In-vitro assays of T-cell proliferation, an in-vivo intradermal delayed hypersensitivity response; cytokine and antibody secretions to several mycobacterial peptide antigens were assessed in healthy, but exposed, West African twins. Candidate gene polymorphisms were typed in the NRAMP1, Vitamin D receptor, IL10, IL4, IL4 receptor and CTLA-4 genes. Variants of the loci IL10 (-1082 G/A), CTLA-4 (49 A/G) and the IL4 receptor (128 A/G) showed significant associations with immune responses to several antigens. T-cell proliferative responses and antibody responses were reduced, TNF-alpha responses were increased for subjects with the CTLA-4 G allele. The T-cell proliferative responses of subjects with IL10 GA and GG genotypes differed significantly. IL4 receptor AG and GG genotypes also showed significant differences in their T-cell proliferative responses to MTB antigens. These results yield a greater understanding of the genetic mechanisms that underlie the immune responses in tuberculosis and have implications for the design of therapeutic interventions
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