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Methods are presented which produce Maximum Likelihood Estimates (MLE) of the degree of heterogeneity in individual mortality risks under a variety of assumptions about the age trajectory of those mortality risks. With these estimates of the degree of population heterogeneity it is possible to adjust comparisons of mortality risks across populations for the effects of population heterogeneity, differential mortality selection, and different age trajectories of the force of mortality. These methods are demonstrated by applying a variety of standard assumptions about the age trajectory of the force of mortality to the analysis of a broad range of cohort mortality data for the U.S. and Swedish populations. The estimates of the degree of heterogeneity, produced under all of the selected force of mortality models, consistently indicated a considerable degree of heterogeneity in mortality risks.  相似文献   
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Biplane projection imaging is one of the primary methods for imaging and visualizing the cardiovascular system in medicine. A key problem in such a technique is to determine the imaging geometry (i.e., the relative rotation and translation) of two projections so that the 3-D structure can be accurately reconstructed. Based on interesting observations and efficient geometric techniques, we present in this paper new algorithmic solutions for this problem. Comparing with existing optimization-based approaches, our techniques yield better accuracy and have bounded execution time, thus is more suitable for on-line applications. Our techniques can easily detect outliers to further improve the accuracy.This research was supported in part by NIH under USPHS grant numbers HL52567.  相似文献   
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For 200 years, criminologists theorized that delinquent and criminal acts arise from deviant psychological states (such as irrationality or immorality) and/or social conditions that produce these psychological states. This theoretical perspective, which is being duplicated in most efforts to understand and control research misconduct, has not been productive. More recently, criminological perspectives have emerged, emphasizing situational factors that enhance or restrict the opportunity for illegal or imprudent behavior. These so-called "opportunity" theories have been shown to have practical value in reducing crime rates. We explore the promise of these newer theories for the responsible conduct of research (RCR).  相似文献   
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In this paper we extend the work reported in prior studies. The conclusion drawn from the aggregate of those studies was that the limitation on liability imposed by the Price–Anderson Act for a catastrophic accident at a nuclear power plant ($560 million) is comparable to de facto limitations on recovery following catastrophic events in many other industries. The analysis in those reports was at a high level of abstraction, comparing almost exclusively the potential loss from high consequence accidents with the current assets of major firms in relevant industries. We found that potential loss exceeded assets.  相似文献   
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The Scientific Community: Organic or Mechanical?   总被引:1,自引:0,他引:1  
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This article discusses the family size utility function (FSUF), which portrays the relative strengths of preferences among family sizes, as held by an individual, couple, or group. Derivable from the FSUF are indications of motivation to seek or avoid additional children, indications which may prove useful for understanding fertility decisions and for predicting completed fertility. A method is described for assessing the FSUF with data obtainable by interview surveys, and case studies of actual FSUF’s are presented. The article concludes with theoretical and empirical questions for further investigation of the FSUF.  相似文献   
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