Utilizing Cause-of-Death Information to Estimate Conditional Probabilities of Disease and Death

Conditional probabilities that do not require the assumption of independence among competing risks for identifiability are proposed for the analysis of carcinogenesis bioassay data as a reasonable adjustment for deaths or other removals due to competing risks. These conditional probabilities permit consideration of one type of tumor at a time, but in such a way that inferences are relevant to actual experimental conditions under which other diseases and causes of death are present and operating. The importance of assigning cause of death in bioassays is demonstrated by the fact that it allows the definition and identification of functions useful in the interpretation of carcinogenesis data, without requiring that a disease of interest be independent from competing risks. However, one proposed conditional probability does require sacrifice data for its identifiability.     

误捕及其对海兽种群的影响

几乎在全世界都有误捕海兽的记录．有误捕记录的海兽有鲸目１４科６２种,鳍脚目３科１２种,海牛目２科２种及食肉目１科１种．误捕海兽的渔具包括刺网、拖网、围网、张网、插网和陷阱等．误捕可导致种群数量的下降及生活史特征的改变．我国需要开展这方面的研究工作．     

Causal inference for non-mortality outcomes in the presence of death

Evaluation of the causal effect of a baseline exposure on a morbidity outcome at a fixed time point is often complicated when study participants die before morbidity outcomes are measured. In this setting, the causal effect is only well defined for the principal stratum of subjects who would live regardless of the exposure. Motivated by gerontologic researchers interested in understanding the causal effect of vision loss on emotional distress in a population with a high mortality rate, we investigate the effect among those who would live both with and without vision loss. Since this subpopulation is not readily identifiable from the data and vision loss is not randomized, we introduce a set of scientifically driven assumptions to identify the causal effect. Since these assumptions are not empirically verifiable, we embed our methodology within a sensitivity analysis framework. We apply our method using the first three rounds of survey data from the Salisbury Eye Evaluation, a population-based cohort study of older adults. We also present a simulation study that validates our method.     

Concomitant Information in Competing Risk Analysis

A competing risk model, accommodating both Type I censoring and random withdrawals, is expanded to incorporate concomitant information by allowing the parameters of the underlying distributions to be a linear function of two covariates. The model is developed for two competing risks, one following a Weibull distribution and the other a Rayleigh distribution, and random withdrawals following a Weibull distribution. A method is developed for testing the equality of the coefficients for a given covariate for each of the competing risks using MLE'.     

化感作用研究中的生物测定方法综述

生物测定是化感作用研究的重要环节。目前很多化感作用研究缺乏规范的生物测定方法。本文对国内外的常用的生物测定方法,这些方法的适应性以及影响生物测定结果的一些因素(如化感物质的收集方法、微生物和溶液渗透压、受体的选择等)进行了综述。并对生物测定结果的表示方法提出了建议。     

A case of Carrion's disease associated with human sacrifice from the Huari culture of Southern Peru

A case of Carrion's disease in the verruga phase from a mummy of the Tiahuanaco culture of Southern Peru is reported. The characteristics of the disease are described as well as the bacterium. The man was apparently sacrificed and certain organs used in rituals.