Influence of human immunodeficiency virus infection on neurological impairment: an analysis of longitudinal binary data with informative drop-out

A study to investigate the human immunodeficiency virus (HIV) status on the course of neurological impairment, conducted by the HIV Center at Columbia University, followed a cohort of HIV positive and negative gay men for 5 years and assessed the presence or absence of neurological impairment every 6 months. Almost half of the subjects dropped out before the end of the study for reasons that might have been related to the missing neurological data. We propose likelihood-based methods for analysing such binary longitudinal data under informative and non-informative drop-out. A transition model is assumed for the binary response, and several models for the drop-out processes are considered which are functions of the response variable (neurological impairment). The likelihood ratio test is used to compare models with informative and non-informative drop-out mechanisms. Using simulations, we investigate the percentage bias and mean-squared error (MSE) of the parameter estimates in the transition model under various assumptions for the drop-out. We find evidence for informative drop-out in the study, and we illustrate that the bias and MSE for the parameters of the transition model are not directly related to the observed drop-out or missing data rates. The effect of HIV status on the neurological impairment is found to be statistically significant under each of the models considered for the drop-out, although the regression coefficient may be biased in certain cases. The presence and relative magnitude of the bias depend on factors such as the probability of drop-out conditional on the presence of neurological impairment and the prevalence of neurological impairment in the population under study.     

民事诉讼举证责任的分配

举证责任的分配是举证责任的核心问题。举证责任包括行为责任和结果责任两方面的含义。“谁主张,谁举证”的一般分配原则,不能合理、有效地解决结果责任的分配。结果责任的分配所要解决的问题是,当诉讼即将终结时若案件事实仍然真伪不明,由谁承担不利的诉讼后果。我国现行的司法解释,完善了举证责任分配的有关规则,但结果责任的分配,尚需确立明确的标准和分配的规则。民事诉讼证据立法需要从实体法和程序法进一步完善,公平、科学地解决举证责任的分配。     

社会认知偏差:群体性事件生成的社会心理启动根源

社会认知偏差是群体性事件生成的深层次社会心理现象,通过对山东部分地区进行抽样调查,并结合近几年来全国群体性事件典型案例的分析发现,生成群体性事件的社会认知偏差,主要包括事件诱因责任归因偏差、行为模式结果预期偏差和行为结果价值偏差。因此,改善法的实施现状,消除社会认知偏差;提高公众法律意识,优化社会认知;建立心理危机干预队伍,合理引导社会认知,是群体性事件社会认知偏差的有效干预对策。     

Back to basics: explaining sample size in outcome trials,are statisticians doing a thorough job?

Time to event outcome trials in clinical research are typically large, expensive and high‐profile affairs. Such trials are commonplace in oncology and cardiovascular therapeutic areas but are also seen in other areas such as respiratory in indications like chronic obstructive pulmonary disease. Their progress is closely monitored and results are often eagerly awaited. Once available, the top line result is often big news, at least within the therapeutic area in which it was conducted, and the data are subsequently fully scrutinized in a series of high‐profile publications. In such circumstances, the statistician has a vital role to play in the design, conduct, analysis and reporting of the trial. In particular, in drug development it is incumbent on the statistician to ensure at the outset that the sizing of the trial is fully appreciated by their medical, and other non‐statistical, drug development team colleagues and that the risk of delivering a statistically significant but clinically unpersuasive result is minimized. The statistician also has a key role in advising the team when, early in the life of an outcomes trial, a lower than anticipated event rate appears to be emerging. This paper highlights some of the important features relating to outcome trial sample sizing and makes a number of simple recommendations aimed at ensuring a better, common understanding of the interplay between sample size and power and the final result required to provide a statistically positive and clinically persuasive outcome. Copyright © 2009 John Wiley & Sons, Ltd.     

Best practices for online Canadian prenatal health promotion: A public health approach

Background

Prenatal health promotion provides information regarding pregnancy risks, protective behaviours and clinical and community resources. Typically, women obtain prenatal health information from health care providers, prenatal classes, peers/family, media and increasingly, Internet sites and mobile apps. Barriers to prenatal health promotion and related services include language, rural/remote location, citizenship and disability. Online public health platforms represent the capacity to reach underserved women and can be customised to address the needs of a heterogeneous population of pregnant women.

论新疆生产建设兵团的历史地位和作用

该文通过对新疆生产建设兵团产生的历史背景及其对开发、建设和保卫新疆的巨大作用的历史回顾 ,阐述了兵团作为新疆经济建设、守卫边防和维护祖国领土完整、保证新疆社会稳定、促进民族团结的重要力量的历史地位及其历史必然性 ;从历史和现实两个方面揭示了屯垦戍边事业在开发建设边疆、稳定边疆、巩固国防中极其重要的战略地位。在改革开放的新时期和西部大开发中 ,兵团具有更加突出的地位 ,更应加快建设和发展 ,发挥更大的作用 ,为党和人民再作新的贡献