3,965 research outputs found

    Disease mapping and regression with count data in the presence of overdispersion and spatial autocorrelation: a Bayesian model averaging approach

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    This paper applies the generalised linear model for modelling geographical variation to esophageal cancer incidence data in the Caspian region of Iran. The data have a complex and hierarchical structure that makes them suitable for hierarchical analysis using Bayesian techniques, but with care required to deal with problems arising from counts of events observed in small geographical areas when overdispersion and residual spatial autocorrelation are present. These considerations lead to nine regression models derived from using three probability distributions for count data: Poisson, generalised Poisson and negative binomial, and three different autocorrelation structures. We employ the framework of Bayesian variable selection and a Gibbs sampling based technique to identify significant cancer risk factors. The framework deals with situations where the number of possible models based on different combinations of candidate explanatory variables is large enough such that calculation of posterior probabilities for all models is difficult or infeasible. The evidence from applying the modelling methodology suggests that modelling strategies based on the use of generalised Poisson and negative binomial with spatial autocorrelation work well and provide a robust basis for inference

    Agility Measures Related to Game Performance of NCAA Baseball Pitchers

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    Like most kinetic chains in athletic performance, the baseball pitching motion begins with the muscles of the legs and continues progressively through the torso, shoulders, and arms. Similarities are noted between the baseball pitching motion and the kinetic chain employed in agility tests that involve acceleration, deceleration, and change of direction measures of agility. Purpose: The purpose of this investigation was to determine pre-season agility in NCAA pitchers and to relate these measures to regular season pitching performance. Methods: NCAA Division II pitchers (n=10, age 20.2 ± 1.9 yrs., weight 83.8 ± 10.3 kg, height 1.85 ± 0.48 m) volunteered as study subjects. A previously described laser-timed 60-yd shuttle run (“JJ Shuttle”) provided average speeds for four contiguous agility segments (S1, S2, S3, and S4 of 10, 10, 20, and 20 yds., respectively), as well as Total Shuttle Run (TSR). Statistical measures obtained from regular season games (n=48), including Runs (R), Hits (H), Earned Runs (ER), Base-on-Balls (BB), and Strikeouts (SO), each normalized for innings pitched, provided evidence of game pitching performance. Pearson’s Correlation Coefficient determined the relationship of average agility speeds to pitching performance. Results: Analysis identified significant correlations (p\u3c.05) between S1, S2, and TSR and normalized SO (r=0.77, r=0.73, and r=0.87, respectively); S3 and S4 were insignificant (r=0.42 and r=0.59, respectively). Additionally, a significant correlation (p\u3c.05) was identified between S3 and BB (r=0.67). Conclusion: Results of this study suggest that better agility may lead to selected improvements in game performance in NCAA Division II baseball pitchers

    Quantitative relationships between benthic diatom assemblages and water chemistry in Macquarie Island lakes and their potential for reconstructing past environmental changes

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    This study is the first published survey of diatom-environment relationships Oil sub-Antarctic Macquarie Island. Fifty-eight sites in 50 coastal and inland lakes were sampled for benthic diatoms and water chemistry. 208 diatom species from 34 genera were identified. Multivariate analyses indicated that the lakes were distributed along nutrient and conductivity gradients. Conductivity, pH, phosphate (SRP), silicate and temperature all explained independent portions of the variance in the diatom data. Transfer functions provide a quantitative basis for palaeolimnological studies of past climate change and human impacts, and can be used to establish baseline conditions for assessing the impacts of recent climate change and the introduction of non-native plants and animals. Statistically robust diatom transfer functions for conductivity, phosphate and silicate were developed, while pH and temperature transfer functions performed less well. The lower predictive abilities of the pH and temperature transfer functions probably reflect the broad pH tolerance range of diatoms on Macquarie Island and uneven distribution of lakes along the temperature gradient. This study contributes to understanding the current ecological distribution of Macquarie Island diatoms and provides transfer functions that will be applied in studies of diatoms in lake sediment cores to quantitatively reconstruct past environmental changes

    Incidence of cardiovascular risk factors by education level 2000-2005 : the Australian diabetes, obesity and lifestyle (AusDiab) cohort study

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    Lower socioeconomic status (SES) is associated with a higher prevalence of major risk factors for cardiovascular disease (CVD). However, few longitudinal studies have examined the association between SES and CVD risk factors over time. We aimed to determine whether SES, using education as a proxy, is associated with the onset of CVD risk factors over 5 years in an Australian adult cohort study. Participants in the Australian Diabetes, Obesity and Lifestyle study (AusDiab) study aged 25 years and over who attended both baseline and 5-year follow-up examinations (n=5 967) were categorised according to educational attainment. Cardiovascular risk factor data at both time points were ascertained through questionnaire and physical measurement. Women with lower education had a greater risk of progressing from normal weight to overweight or obesity than those with higher education (age-adjusted OR 1.57, 95% CI 1.06-2.31). Both men and women with lower education were more likely to develop diabetes (age-adjusted OR from higher education 1.75, 95% CI 1.14-2.71 and 3.01, 95% CI 1.26-7.20, respectively). A lower level of education was associated with a greater number of risk factors accumulated over time in women (OR of progressing from having two or less risk factors at baseline to three or more at follow up, 2.04, 95% 1.32-3.14). In this Australian population-based study, lower educational attainment was associated with an increased risk of developing both individual and total CVD risk factors over a 5-year period. These findings suggest that SES inequalities in CVD will persist into the future.<br /

    Importance of cattle biodiversity and its influence on the nutrient composition of beef

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    Livestock make a substantial contribution to achieving food and nutrition security due to various factors including the high nutritional quality of animal-source foods. Conservation and sustainable use of cattle genetic resources are important due to the multiple benefits provided by local breeds. These benefits include multiple direct uses, additional market value provided by specialty products, social and cultural roles, and adaptations that local breeds have to climate and diseases in harsh environments. Meat composition varies across cattle breeds. Whereas genetics play a role in this variation, management practices, such as diet, and other environmental factors also affect nutrient composition. Compositional data for cattle breeds have been added to the FAO/INFOODS Food Composition Database for Biodiversity. The database is publicly available and has value for use by researchers, nutritionists, producers, the general public and other stakeholders. More compositional data, including amino acids, minerals, and vitamins, are needed from local breeds in order to understand better the nutritional benefits of sustainably managing animal genetic resources

    Decadal changes in summertime reactive oxidized nitrogen and surface ozone over the Southeast United States

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    Widespread efforts to abate ozone (O3) smog have significantly reduced emissions of nitrogen oxides (NOx) over the past 2 decades in the Southeast US, a place heavily influenced by both anthropogenic and biogenic emissions. How reactive nitrogen speciation responds to the reduction in NOx emissions in this region remains to be elucidated. Here we exploit aircraft measurements from ICARTT (July–August 2004), SENEX (June–July 2013), and SEAC4RS (August–September 2013) and long-term ground measurement networks alongside a global chemistry–climate model to examine decadal changes in summertime reactive oxidized nitrogen (RON) and ozone over the Southeast US. We show that our model can reproduce the mean vertical profiles of major RON species and the total (NOy) in both 2004 and 2013. Among the major RON species, nitric acid (HNO3) is dominant (∼ 42–45%), followed by NOx (31%), total peroxy nitrates (ΣPNs; 14%), and total alkyl nitrates (ΣANs; 9–12%) on a regional scale. We find that most RON species, including NOx, ΣPNs, and HNO3, decline proportionally with decreasing NOx emissions in this region, leading to a similar decline in NOy. This linear response might be in part due to the nearly constant summertime supply of biogenic VOC emissions in this region. Our model captures the observed relative change in RON and surface ozone from 2004 to 2013. Model sensitivity tests indicate that further reductions of NOxemissions will lead to a continued decline in surface ozone and less frequent high-ozone events
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