Impact of safety monitoring on error probabilities of binary efficacy outcome analyses in large phase III group sequential trials

In phase III clinical trials, some adverse events may not be rare or unexpected and can be considered as a primary measure for safety, particularly in trials of life-threatening conditions, such as stroke or traumatic brain injury. In some clinical areas, efficacy endpoints may be highly correlated with safety endpoints, yet the interim efficacy analyses under group sequential designs usually do not consider safety measures formally in the analyses. Furthermore, safety is often statistically monitored more frequently than efficacy measures. Because early termination of a trial in this situation can be triggered by either efficacy or safety, the impact of safety monitoring on the error probabilities of efficacy analyses may be nontrivial if the original design does not take the multiplicity effect into account. We estimate the actual error probabilities for a bivariate binary efficacy-safety response in large confirmatory group sequential trials. The estimated probabilities are verified by Monte Carlo simulation. Our findings suggest that type I error for efficacy analyses decreases as efficacy-safety correlation or between-group difference in the safety event rate increases. In addition, although power for efficacy is robust to misspecification of the efficacy-safety correlation, it decreases dramatically as between-group difference in the safety event rate increases.     

Estimation of the Burr type III distribution with application in unified hybrid censored sample of fracture toughness

In this paper, the statistical inference of the unknown parameters of a Burr Type III (BIII) distribution based on the unified hybrid censored sample is studied. The maximum likelihood estimators of the unknown parameters are obtained using the Expectation–Maximization algorithm. It is observed that the Bayes estimators cannot be obtained in explicit forms, hence Lindley's approximation and the Markov Chain Monte Carlo (MCMC) technique are used to compute the Bayes estimators. Further the highest posterior density credible intervals of the unknown parameters based on the MCMC samples are provided. The new model selection test is developed in discriminating between two competing models under unified hybrid censoring scheme. Finally, the potentiality of the BIII distribution to analyze the real data is illustrated by using the fracture toughness data of the three different materials namely silicon nitride (Si₃N₄), Zirconium dioxide (ZrO₂) and sialon (Si_6?xAl_xO_xN_8?x). It is observed that for the present data sets, the BIII distribution has the better fit than the Weibull distribution which is frequently used in the fracture toughness data analysis.     

新巴塞尔资本协议中的信用风险管理启示

信用风险管理是银行业风险管理的主要内容。新巴塞尔协议中对信用风险管理包括标准法和内部评级法。对我国银行业的启示是:转变我国银行业经营理念,完善内部评级体系,构建自己的现代风险管理模型等。     

Robust Estimation for Parameters of the Extended Burr Type III Distribution

We consider various robust estimators for the extended Burr Type III (EBIII) distribution for complete data with outliers. The considered robust estimators are M-estimators, least absolute deviations, Theil, Siegel's repeated median, least trimmed squares, and least median of squares. Before we perform the aforementioned estimators for the EBIII, we adapt the quantiles method to the estimation of the shape parameter k of the EBIII. The simulation results show that the considered robust estimators generally outperform the existing estimation approaches for data with upper outliers, with certain of them retaining a relatively high degree of efficiency for small sample sizes.     

A test of the dsm‐III‐R'S implicit assumption that fetishistic arousal and gender dysphoria are mutually exclusive

This study sought to determine the proportion of adult, male, heterosexual cross‐dressers who acknowledge both gender dysphoria and at least occasional fetishistic response to cross‐dressing. Subjects were 193 outpatients of the gender identity clinic or behavioral sexology department of a psychiatric teaching hospital. Questionnaire items were used to assess subjects' current level of gender dysphoria and their recent history of sexual response to cross‐dressing. Subjects who reported higher levels of gender dysphoria tended to report lower frequencies of sexual arousal with cross‐dressing (r = ‐.56, p < .0001) and lower frequencies of masturbation with cross‐dressing (r = ‐.62, p < .0001). About half of even the most strongly gender dysphoric subjects, however, acknowledged that they still become sexually aroused or masturbate at least occasionally when cross‐dressing. These findings indicate a need for revision in the DSM‐III‐R's diagnostic criteria for transvestism and gender identity disorders, which presuppose that gender dysphoria and fetishistic reactions are mutually exclusive.     

非有机溶剂萃取光度法测定钯的研究--PEG--Arsenazo Ⅲ--Na2SO4体系

本文研究了偶氮胂Ⅲ作为萃取剂和显色剂,在PEG-ArsenazoⅢ-Na2SO4体系中的非有机溶剂萃取光度法测定钯.将配合物从PH3.5(HAc～NaAc缓冲溶液)的溶液中萃取至PEG相,其最大吸收波长位于610nm,摩尔吸光系数为5.0×104L·mol-1·cm-1,Pd(11)的线性范围为0～4μg/ml,Pd(11)与ArsenazoⅢ的配合比为12.将方法用于C-Pd催化剂中钯的测定,获得满意结果.     

新巴塞尔协议与我国银行监管

巴塞尔协议代表着国际银行业监管的发展趋势。本文介绍了巴塞尔协议的发展历程及其监管思想的演变,分析了新巴塞尔协议的特点,提出了完善我国银行监管的措施。     

责任转型与软法回归：《哥本哈根协议》与气候变化的国际法治理

国际社会正依托《哥本哈根协议》继续推进气候变化的国际法治理进程,未来气候变化的全球治理仍将围绕“共同但有区别责任”的适用而展开,并向“区别而又共同责任”的目标转型。《协议》经由“人类共同关切事项”认同了“共同责任”的内涵,通过实质性公平原则,明确了“区别责任”的要旨,随着《协议》的落实和发展,国际社会将认同《协议》表现出来的“软法”特性,弥合各方分歧,促进“为今世后代保护全球气候”的可持续发展目标的实现。     

《华盛顿协议》与高等工程教育教师职业发展

随着全球化进程的不断加快和我国加入WTO后所面临的高等工程高质量专业人才的缺乏,我国的高等工程教育改革必须与国际接轨,而《华盛顿协议》提供了可资借鉴的政策框架,是我国高等工程教育师资实施专业化培养,从而形成一支具备国际等效性的、工程教育能力结构合理的师资队伍是重要的路径选择。