288 research outputs found

    Modelling-based identification of factors influencing campylobacters in chicken broiler houses and on carcasses sampled after processing and chilling

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    Publication history: Accepted - 30 January 2017; Published online - 4 March 2017.Aims: To identify production and processing practices that might reduceCampylobacter numbers contaminating chicken broiler carcasses.Methods and Results: The numbers of campylobacters were determined oncarcass neck skins after processing or in broiler house litter samples.Supplementary information that described farm layouts, farming conditions forindividual flocks, the slaughterhouse layouts and operating conditions insideplants was collected, matched with each Campylobacter test result. Statisticalmodels predicting the numbers of campylobacters on neck skins and in litterwere constructed. Carcass microbial contamination was more stronglyinfluenced by on-farm production practices compared with slaughterhouseactivities. We observed correlations between the chilling, washing anddefeathering stages of processing and the numbers of campylobacters oncarcasses. There were factors on farm that also correlated with numbers ofcampylobacters in litter. These included bird gender, the exclusion of dogsfrom houses, beetle presence in the house litter and the materials used toconstruct the house frame.Conclusions: Changes in farming practices have greater potential for reducingchicken carcass microbial contamination compared with processinginterventions.Significance and Impact of the Study: Routine commercial practices wereidentified that were correlated with lowered numbers of campylobacters.Consequently, these practices are likely to be both cost-effective and suitablefor adoption into established farms and commercial processingThis work was funded by the United Kingdom Food Standards Agency (FSA) as projects FS241051A and FS101123

    Quotients of AdS_{p+1} x S^q: causally well-behaved spaces and black holes

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    Starting from the recent classification of quotients of Freund--Rubin backgrounds in string theory of the type AdS_{p+1} x S^q by one-parameter subgroups of isometries, we investigate the physical interpretation of the associated quotients by discrete cyclic subgroups. We establish which quotients have well-behaved causal structures, and of those containing closed timelike curves, which have interpretations as black holes. We explain the relation to previous investigations of quotients of asymptotically flat spacetimes and plane waves, of black holes in AdS and of Godel-type universes.Comment: 48 pages; v2: minor typos correcte

    On the origin of M81 group extended dust emission

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    Galactic cirrus emission at far-infrared wavelengths affects many extragalactic observations. Separating this emission from that associated with extragalactic objects is both important and difficult. In this paper we discuss a particular case, the M81 group, and the identification of diffuse structures prominent in the infrared, but also detected at optical wavelengths. The origin of these structures has previously been controversial, ranging from them being the result of a past interaction between M81 and M82 or due to more local Galactic emission. We show that over an order of a few arcmin scales, the far-infrared (Herschel 250 mu m) emission correlates spatially very well with a particular narrow-velocity (2-3 km s(-1)) component of the Galactic HI. We find no evidence that any of the far-infrared emission associated with these features actually originates in the M81 group. Thus we infer that the associated diffuse optical emission must be due to galactic light-back scattered off dust in our galaxy. Ultraviolet observations pick out young stellar associations around M81, but no detectable far-infrared emission. We consider in detail one of the Galactic cirrus features, finding that the far-infrared HI relation breaks down below arcmin scales and that at smaller scales there can be quite large dust-temperature variation

    Effect of Adopting the New Race-Free 2021 Chronic Kidney Disease Epidemiology Collaboration Estimated Glomerular Filtration Rate Creatinine Equation on Racial Differences in Kidney Disease Progression among People with Human Immunodeficiency Virus: An Observational Study

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    Background: The impact of adopting a race-free estimated glomerular filtration rate (eGFR) creatinine (eGFRcr) equation on racial differences in chronic kidney disease (CKD) progression among people with human immunodeficiency virus (PWH) is unknown. Methods: We defined eGFR stages using the original race-adjusted Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) eGFRcr equation and the new race-free CKD-EPI eGFRcr equation. We then estimated 5-year probabilities of transitioning from baseline kidney function to more advanced eGFR stages and examined the association of race (black vs white) with rates of CKD progression using Markov models. Results: With the race-adjusted eGFRcr equation, black participants (n = 31 298) had a lower risk of progressing from eGFR stage 1 to 2 (hazard ratio [HR], 0.77; 95% confidence interval [CI],. 73-.82), an equal risk of progressing from stage 2 to 3 (1.00;. 92-.07) and a 3-fold risk of progressing from stage 3 to 4 or 5 (3.06; 2.60-3.62), compared with white participants (n = 27 542). When we used the race-free eGFRcr equation, 16% of black participants were reclassified into a more severe eGFR stage at baseline. The reclassified black individuals had a higher prevalence of CKD risk factors than black PWH who were not reclassified. With the race-free eGFRcr equation, black participants had a higher risk of disease progression across all eGFR stages than white participants. Conclusions: The original eGFRcr equation systematically masked a subgroup of black PWH who are at high-risk of CKD progression. The new race-free eGFRcr equation unmasks these individuals and may allow for earlier detection and management of CKD

    Optical Constants of Ices Important to Planetary Science From Laboratory Reflectance Spectroscopy

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    Laboratory-derived optical constants are essential for identifying ices and measuring their relative abundances on Solar System objects. Almost all optical constants of ices important to planetary science come from experiments with transmission geometries. Here, we describe our new experimental setup and the modification of an iterative algorithm in the literature to measure the optical constants of ices from experiments with reflectance geometries. We apply our techniques to CH4 ice and H2O ice samples and find good agreement between our values and those in the literature, except for one CH4 band in the literature that likely suffers from saturation. The work we present here demonstrates that labs with reflectance geometries can generate optical constants essential for the proper analysis of near- and mid-infrared spectra of outer Solar System objects such as those obtained with the James Webb Space Telescope

    Optical Constants of Ices Important to Planetary Science From Laboratory Reflectance Spectroscopy

    Get PDF
    Laboratory-derived optical constants are essential for identifying ices and measuring their relative abundances on Solar System objects. Almost all optical constants of ices important to planetary science come from experiments with transmission geometries. Here, we describe our new experimental setup and the modification of an iterative algorithm in the literature to measure the optical constants of ices from experiments with reflectance geometries. We apply our techniques to CH4 ice and H2O ice samples and find good agreement between our values and those in the literature, except for one CH4 band in the literature that likely suffers from saturation. The work we present here demonstrates that labs with reflectance geometries can generate optical constants essential for the proper analysis of near- and mid-infrared spectra of outer Solar System objects such as those obtained with the James Webb Space Telescope
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