4,912 research outputs found

    Measurement error caused by spatial misalignment in environmental epidemiology

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    Copyright @ 2009 Gryparis et al - Published by Oxford University Press.In many environmental epidemiology studies, the locations and/or times of exposure measurements and health assessments do not match. In such settings, health effects analyses often use the predictions from an exposure model as a covariate in a regression model. Such exposure predictions contain some measurement error as the predicted values do not equal the true exposures. We provide a framework for spatial measurement error modeling, showing that smoothing induces a Berkson-type measurement error with nondiagonal error structure. From this viewpoint, we review the existing approaches to estimation in a linear regression health model, including direct use of the spatial predictions and exposure simulation, and explore some modified approaches, including Bayesian models and out-of-sample regression calibration, motivated by measurement error principles. We then extend this work to the generalized linear model framework for health outcomes. Based on analytical considerations and simulation results, we compare the performance of all these approaches under several spatial models for exposure. Our comparisons underscore several important points. First, exposure simulation can perform very poorly under certain realistic scenarios. Second, the relative performance of the different methods depends on the nature of the underlying exposure surface. Third, traditional measurement error concepts can help to explain the relative practical performance of the different methods. We apply the methods to data on the association between levels of particulate matter and birth weight in the greater Boston area.This research was supported by NIEHS grants ES012044 (AG, BAC), ES009825 (JS, BAC), ES007142 (CJP), and ES000002 (CJP), and EPA grant R-832416 (JS, BAC)

    Aplikasi Game Mewarnai dengan Macromedia Flash 8

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    Scientific writing is about the making of Game edutaintment.yang intended forchildren age play group, kindergarten and elementary school children in grade 1,many included images that allows users colored objects in coloredgambar.Game consists of two core components. The first component is thechoice of colors, usually displayed with the color blocks and objects whichbecome targets coloring and added sound notification on every color. Incompleting this writing, the author approached by reading books, articles andbrowse the Internet to get as much information so it can be used to solve theproblem in this writing

    Cooperative damping mechanism of the resonance in the nuclear photoabsorption

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    We propose a resonance damping mechanism to explain the disappearance of the peaks around the position of the resonances higher than the Δ\Delta resonance in the nuclear photoabsorption. This phenomenon is understood by taking into account the cooperative effect of the collision broadening of Δ\Delta and NN^{*}, the pion distortion and the interference in the two-pion photoproduction processes in the nuclear medium.Comment: 11 pages, uses revtex.sty. To appear in Phys. Rev. Let