Statistical testing strategies for assessing treatment efficacy and marker accuracy in phase III trials

When a candidate predictive marker is available, but evidence on its predictive ability is not sufficiently reliable, all‐comers trials with marker stratification are frequently conducted. We propose a framework for planning and evaluating prospective testing strategies in confirmatory, phase III marker‐stratified clinical trials based on a natural assumption on heterogeneity of treatment effects across marker‐defined subpopulations, where weak rather than strong control is permitted for multiple population tests. For phase III marker‐stratified trials, it is expected that treatment efficacy is established in a particular patient population, possibly in a marker‐defined subpopulation, and that the marker accuracy is assessed when the marker is used to restrict the indication or labelling of the treatment to a marker‐based subpopulation, ie, assessment of the clinical validity of the marker. In this paper, we develop statistical testing strategies based on criteria that are explicitly designated to the marker assessment, including those examining treatment effects in marker‐negative patients. As existing and developed statistical testing strategies can assert treatment efficacy for either the overall patient population or the marker‐positive subpopulation, we also develop criteria for evaluating the operating characteristics of the statistical testing strategies based on the probabilities of asserting treatment efficacy across marker subpopulations. Numerical evaluations to compare the statistical testing strategies based on the developed criteria are provided.     

人的视觉心理艺术浅析

本文就人的视觉在对事物的色彩、形式、形状、光和影等诸方面,所产生的心理艺术影响作了剖析。并论述了视觉心理在电影、绘画等艺术创作中的重要性。从而激励人们更好地关注和创作美的作品。     

回到架上——兼论绘画与其他视觉传媒的相互转译

就当下艺术现状,尤其是架上艺术危机的分析,展开对绘画思想性的深刻思索,并通过对绘画与现代视觉传播媒介相互转译实验探讨,求取两者的不同所在,进而反映笔者对艺术现状的感知焦虑,以期在艺术的纯粹思维与纯粹摹写之间划定一个合理的空间,亦即确立纯艺术领域,用以对抗艺术消亡论观点.     

无限传递尽在秋波--试论中外影视对眼睛和眼神的处理

本文通过对中外影视名片中眼睛、眼神的分析,阐述其在影视艺术中所起的重要作用.观众在鉴赏影视作品时,要善于把握银幕上种种无声语言及各种细节,这对吸取艺术精华,获得审美愉悦有着极为显著的意义.     

基于视觉模型的双正交小波图像水印算法

提出了一种基于人类视觉系统模型的双正交小波多分辨图像水印算法,该算法充分利用小波多分辨的优点及人眼视觉系统的特性,保证了水印的不可见性及鲁棒性,同时在检测水印时也不需要原始图像,仅需涉及到相关的几个细节子图。实验表明该水印算法对于中值滤波、叠加加性噪声、JPEG有损压缩三种图像处理都是鲁棒的。检测算法还有计算量小,检测速度快的特点。     

康德先验逻辑的基本问题

康德的先验逻辑对传统哲学特别是形而上学所运用的范畴在分类的基础上作了新的理解,指出了范畴作为思维的逻辑功能,是对感性直观的固有关系。这就决定了先验逻辑的基本问题是范畴与直观的固有关系问题。它构成先验逻辑不同于形式逻辑和思辨逻辑的根本点。     

Predictive Bayesian Microbial Dose-Response Assessment Based on Suggested Self-Organization in Primary Illness Response: Cryptosporidium parvum

The probability of illness caused by very low doses of pathogens cannot generally be tested due to the numbers of subjects that would be needed, though such assessments of illness dose response are needed to evaluate drinking water standards. A predictive Bayesian dose-response assessment method was proposed previously to assess the unconditional probability of illness from available information and avoid the inconsistencies of confidence-based approaches. However, the method uses knowledge of the conditional dose-response form, and this form is not well established for the illness endpoint. A conditional parametric dose-response function for gastroenteric illness is proposed here based on simple numerical models of self-organized host-pathogen systems and probabilistic arguments. In the models, illnesses terminate when the host evolves by processes of natural selection to a self-organized critical value of wellness. A generalized beta-Poisson illness dose-response form emerges for the population as a whole. Use of this form is demonstrated in a predictive Bayesian dose-response assessment for cryptosporidiosis. Results suggest that a maximum allowable dose of 5.0 x 10(-7) oocysts/exposure (e.g., 2.5 x 10(-7) oocysts/L water) would correspond with the original goals of the U.S. Environmental Protection Agency Surface Water Treatment Rule, considering only primary illnesses resulting from Poisson-distributed pathogen counts. This estimate should be revised to account for non-Poisson distributions of Cryptosporidium parvum in drinking water and total response, considering secondary illness propagation in the population.     

Causal Reasoning from Longitudinal Data*

Abstract. This paper reviews some of the key statistical ideas that are encountered when trying to find empirical support to causal interpretations and conclusions, by applying statistical methods on experimental or observational longitudinal data. In such data, typically a collection of individuals are followed over time, then each one has registered a sequence of covariate measurements along with values of control variables that in the analysis are to be interpreted as causes, and finally the individual outcomes or responses are reported. Particular attention is given to the potentially important problem of confounding. We provide conditions under which, at least in principle, unconfounded estimation of the causal effects can be accomplished. Our approach for dealing with causal problems is entirely probabilistic, and we apply Bayesian ideas and techniques to deal with the corresponding statistical inference. In particular, we use the general framework of marked point processes for setting up the probability models, and consider posterior predictive distributions as providing the natural summary measures for assessing the causal effects. We also draw connections to relevant recent work in this area, notably to Judea Pearl's formulations based on graphical models and his calculus of so‐called do‐probabilities. Two examples illustrating different aspects of causal reasoning are discussed in detail.     

经济责任审计与执政能力建设的若干思考

从经济责任审计的实际出发，联系工作实践，对目前经济责任审计中存在的问题进行了探讨，并提出了相应的对策，试图能解决当前经济责任审计中碰到的一些问题，进一步加强经济责任审计对权力制约和监督的作用，促进领导干部提高执政能力，推动经济社会全面和谐发展．     

学校本位教学视导模式的实证研究——以兰州市E中学为例

本研究目的在于通过对兰州市E中学施行的学校本位教学视导模式的深入观察,全方位了解学校本位教学视导模式的具体运作方式。以兰州市一所薄弱学校为研究场域,通过课堂观察的方式,全面了解学校为提高办学质量所开展的“学案分组教学法”,及进行学校本位化视导模式的具体运作状态。在兰州市E中学开展学校本位教学视导模式的过程中,学校校长与某大学教育学院课程与教学领域的教授专家参与视导过程。主要采取校长主导,专家参与的合作视导方式,对兰州市E中学初中二年级屈老师数学课进行为期一周的教学观察与记录。实施以学校为本位的合作视导方式,目的在于发现兰州市E中学进行“学案分组教学法”中的具体教学问题,通过大学与中学的合作,开展学校本位视导模式,有效促进教师的专业发展与增强教学有效性,提高学校办学质量。