1,157 research outputs found

    Fast computation by block permanents of cumulative distribution functions of order statistics from several populations

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    The joint cumulative distribution function for order statistics arising from several different populations is given in terms of the distribution function of the populations. The computational cost of the formula in the case of two populations is still exponential in the worst case, but it is a dramatic improvement compared to the general formula by Bapat and Beg. In the case when only the joint distribution function of a subset of the order statistics of fixed size is needed, the complexity is polynomial, for the case of two populations.Comment: 21 pages, 3 figure

    Not all surveillance data are created equal—A multi‐method dynamic occupancy approach to determine rabies elimination from wildlife

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    1. A necessary component of elimination programmes for wildlife disease is effective surveillance. The ability to distinguish between disease freedom and non‐detection can mean the difference between a successful elimination campaign and new epizootics. Understanding the contribution of different surveillance methods helps to optimize and better allocate effort and develop more effective surveillance programmes. 2. We evaluated the probability of rabies virus elimination (disease freedom) in an enzootic area with active management using dynamic occupancy modelling of 10 years of raccoon rabies virus (RABV) surveillance data (2006–2015) collected from three states in the eastern United States. We estimated detection probability of RABV cases for each surveillance method (e.g. strange acting reports, roadkill, surveillance‐trapped animals, nuisance animals and public health samples) used by the USDA National Rabies Management Program. 3. Strange acting, found dead and public health animals were the most likely to detect RABV when it was present, and generally detectability was higher in fall– winter compared to spring–summer. Found dead animals in fall–winter had the highest detection at 0.33 (95% CI: 0.20, 0.48). Nuisance animals had the lowest detection probabilities (~0.02). 4. Areas with oral rabies vaccination (ORV) management had reduced occurrence probability compared to enzootic areas without ORV management. RABV occurrence was positively associated with deciduous and mixed forests and medium to high developed areas, which are also areas with higher raccoon (Procyon lotor) densities. By combining occupancy and detection estimates we can create a probability of elimination surface that can be updated seasonally to provide guidance on areas managed for wildlife disease. 5. Synthesis and applications. Wildlife disease surveillance is often comprised of a combination of targeted and convenience‐based methods. Using a multi‐method analytical approach allows us to compare the relative strengths of these methods, providing guidance on resource allocation for surveillance actions. Applying this multi‐method approach in conjunction with dynamic occupancy analyses better informs management decisions by understanding ecological drivers of disease occurrence

    Temporal change in maternal dietary intake during pregnancy and lactation between and within 2 pregnancy cohorts assembled in the United Kingdom

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    Background: The association between maternal and infant dietary exposures and risk of allergic disease development is an area of considerable scientific uncertainty. Objective: This study aims to compare dietary habits during pregnancy and lactation in two pre-birth cohorts from the same location approximately 10 years apart, a timeframe characterised by changes in government dietary advice. Methods: The FAIR cohort is an unselected birth cohort born between 2001-2002. The 3rd generation cohort was born between 2010-2018. Both cohorts were established on the Isle of Wight (UK) to investigate prevalence of allergic diseases. Nutrition and allergy data was collected prospectively from recruitment and throughout the infant’s early life. Here we present dietary data collected in the third trimester of pregnancy and at three months of age. Differences between cohorts were tested using t-tests, Wilcoxon rank sum tests, chi-squared and Fisher’s exact tests. Results: Data was available for 1331 participants (969 FAIR and 362 3rd generation). The proportion of mothers that reported excluding peanuts during pregnancy was significantly lower for the 3rd generation compared to the FAIR cohort (16.0% vs. 55.6%, p < 0.01). Cohort membership, primiparity, and maternal education were significantly associated with excluding peanuts during pregnancy (p < 0.01). The proportion of mothers who reported excluding any foods during breastfeeding was significantly lower for the 3rd generation compared to the FAIR cohort (22.8% vs. 43.4%, p < 0.01). Conclusion: Maternal exclusion of peanut during pregnancy was lower for mothers giving birth between 2012-2018, compared to mothers giving birth between 2001-2002

    Measurement of the Proton Asymmetry Parameter C in Neutron Beta Decay

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    The proton asymmetry parameter C in neutron decay describes the correlation between neutron spin and proton momentum. In this Letter, the first measurement of this quantity is presented. The result C=-0.2377(26) agrees with the Standard Model expectation. The coefficient C provides an additional parameter for new and improved Standard Model tests. From a differential analysis of the same data (assuming the Standard Model), we obtain lambda=-1.275(16) as ratio of axial-vector and vector coupling constant.Comment: 4 pages, 2 figure

    Studies of parton thermalization at RHIC

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    We consider the evolution of a parton system which is formed in the central region just after a relativistic heavy ion collision. The parton consist of mostly gluons, minijets, which are produced by elastic scattering between constituent partons of the colliding nuclei. We assume the system can be described by a semi-classical Boltzmann transport equation, which we solve by means of the test particle Monte-Carlo method including retardation. The partons proliferate via secondary radiative gg→ggggg \to ggg processes until the thermalization is reached for some assumptions. The extended system is thermalized at about t=1.6t=1.6 fm/cc with T=570T = 570 MeV and stays in equilibrium for about 2 fm/cc with breaking temperature T=360T = 360 MeV in the rapidity central region.Comment: 14 page

    Two-Modality Mammography May Confer an Advantage Over Either Full-Field Digital Mammography or Screen-Film Mammography

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    To compare the cancer detection rate and ROC area under the curve of full-field digital mammography, screen-film mammography, and a combined technique that allowed diagnosis if a finding was suspicious on film, on digital, or both

    Background due to stored electrons following nuclear decays in the KATRIN spectrometers and its impact on the neutrino mass sensitivity

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    The KATRIN experiment is designed to measure the absolute neutrino mass scale with a sensitivity of 200 meV at 90% C.L. by high resolution tritium beta-spectroscopy. A low background level of 10 mHz at the beta-decay endpoint is required in order to achieve the design sensitivity. In this paper we discuss a novel background source arising from magnetically trapped keV electrons in electrostatic retarding spectrometers. The main sources of these electrons are alpha-decays of the radon isotopes (219,220)Rn as well as beta-decays of tritium in the volume of the spectrometers. We characterize the expected background signal by extensive MC simulations and investigate the impact on the KATRIN neutrino mass sensitivity. From these results we refine design parameters for the spectrometer vacuum system and propose active background reduction methods to meet the stringent design limits for the overall background rate

    Exposure to secondhand smoke, exclusive breastfeeding and infant adiposity at age 5 months in the Healthy Start study

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    Background: Infant adiposity may be influenced by several environmental risk factors, but few studies have explored these interactions. Objective: To examine the interaction between exposure to secondhand smoke and breastfeeding exclusivity on adiposity at age 5 months. Methods: We studied 813 mother-offspring pairs from the longitudinal Healthy Start study. Fat mass and fat-free mass were measured by air displacement plethysmography. Linear regression analyses were used to estimate the association between household smokers (none, any) with fat mass, fat-free mass, percent fat mass, weight-for-age z-score, weight-for-length z-score and BMI-for-age z-score as separate outcomes. Interaction terms between household smokers and breastfeeding exclusivity (<5 months, ≄5 months) were added to separate models. Results: The combination of exposure to secondhand smoke and a lack of exclusive breastfeeding was associated with increased adiposity at age 5 months. For example, within the not exclusively breastfed strata, exposure to secondhand smoke was associated with increased fat mass (0.1 kg; 95% CI: 0.0–0.2; P = 0.05). Conversely, within the exclusively breastfed strata, there was virtually no difference in fat mass between exposed and non-exposed infants (coefficient: −0.1; 95% CI: −0.3–0.1; P = 0.25). Conclusions: Our findings may inform new public health strategies with potential relevance for both smoking cessation and obesity prevention
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