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.     

在位相空间中求解外力含时的受迫量子谐振子

运用广义线性量子变换理论 ,在位相空间中通过算子的代数运算求解外力含时的受迫谐振子 ,给出了演化算子、演化算子矩阵元和波函数的表示式 .     

A NOTE ON EVANESCENT PROCESSES

This note examines the connection between μ-invariant measures for the transition function of a continuous-time Markov chain and those of its q-matrix, Q. The major result establishes a necessary and aufficient condition for a convergent μ-invariant measure for Q to be μ-inhant for the minimal transition function, P, under the assumption that P is honest. This corrects Theorem 6 of Vere-Jones (1969) and the first part of Corollary 1 of Pollett (1986), both of which assert that the above conclusion holds in the absence of this condition. The error was pointed out by E.A. van Doom (1991) and the counterexample which be presented provides the basis for the present arguments. In determining where the error occurred in the original proof, we are able to identify a simple sufficient condition for μ-invariance.     

客户生命周期模式研究

客户关系具有周期性,可划分为考察期、形成期、稳定期和退化期四个阶段.交易额和客户利润被选作特征变量来描述客户关系水平,理论分析表明:两者均随生命周期阶段的发展而不断提升,考察期最小,形成期次小,稳定期最大.实证研究检验了该结论的正确性.根据客户关系退出时所处的阶段,客户生命周期模式被分成早期流产型、中途夭折型、提前退出型、长久保持型四种基本类型,每种类型均有不同的成因.     

我国高校文科学报的“当代化”论

高校文科学报的“当代化”是相对于时下盛行的“现代化”而言的。它是根据我国高校文科学报的发生及其发展历程的阶段性特征 ,以及“当代化”所蕴涵的人类文明进程的阶段性定位和“与时俱进”的时代性体现的科学内涵而提出来的。“当代化”具有现实性和求真性的鲜明特征 ,对于 2 1世纪我国高校文科学报的发展是一种求真务实的选择。     

律师在侦查阶段的诉讼地位和作用

律师在侦查阶段介入刑事诉讼不享有辩护人的独立诉讼地位 ,其法律行为具有法律帮助性质 ,主要为犯罪嫌疑人提供法律咨询 ,代理申诉、控告和为犯罪嫌疑人申请取保候审等。这种界定不仅有利于明确律师在侦查阶段的职责 ,也有利于打消认为律师介入侦查将带来太多负效应的顾虑。     

土家族的机智人物故事

机智人物故事是民间故事中的特殊类型,是以一个机智人物为中心所形成的系列故事,有着不同于一般生活故事和民间笑话的审美特征。土家族机智人物故事有着流传空间相对稳定,主人公因地而异的特点,体现着平衡心理的重要社会功能。     

Computing maximum likelihood estimates from type II doubly censored exponential data

It is well-known that, under Type II double censoring, the maximum likelihood (ML) estimators of the location and scale parameters, θ and δ, of a twoparameter exponential distribution are linear functions of the order statistics. In contrast, when θ is known, theML estimator of δ does not admit a closed form expression. It is shown, however, that theML estimator of the scale parameter exists and is unique. Moreover, it has good large-sample properties. In addition, sharp lower and upper bounds for this estimator are provided, which can serve as starting points for iterative interpolation methods such as regula falsi. Explicit expressions for the expected Fisher information and Cramér-Rao lower bound are also derived. In the Bayesian context, assuming an inverted gamma prior on δ, the uniqueness, boundedness and asymptotics of the highest posterior density estimator of δ can be deduced in a similar way. Finally, an illustrative example is included.     

ispLSI1016在数字锁相环中的应用

讨论了采用ispLSI1 0 1 6构造数字锁相环的基本方法 ,并给出了分频器、相位比较器和吞脉冲计数器的相应的编码指令     

Multivariate distributions defined in terms of contours

The paper deals with the problem of using contours as the basis for defining probability distributions. First, the most general probability densities with given contours are obtained and the particular cases of circular and elliptical contours are dealt with. It is shown that the so-called elliptically contoured distributions do not include all possible cases. Next, the case of contours defined by polar coordinates is analyzed including its simulation and parameter estimation. Finally, the case of cumulative distribution functions with given contours is discussed. Several examples are used for illustrative purposes.