Properties of the weighted log‐rank test in the design of confirmatory studies with delayed effects

Proportional hazards are a common assumption when designing confirmatory clinical trials in oncology. This assumption not only affects the analysis part but also the sample size calculation. The presence of delayed effects causes a change in the hazard ratio while the trial is ongoing since at the beginning we do not observe any difference between treatment arms, and after some unknown time point, the differences between treatment arms will start to appear. Hence, the proportional hazards assumption no longer holds, and both sample size calculation and analysis methods to be used should be reconsidered. The weighted log‐rank test allows a weighting for early, middle, and late differences through the Fleming and Harrington class of weights and is proven to be more efficient when the proportional hazards assumption does not hold. The Fleming and Harrington class of weights, along with the estimated delay, can be incorporated into the sample size calculation in order to maintain the desired power once the treatment arm differences start to appear. In this article, we explore the impact of delayed effects in group sequential and adaptive group sequential designs and make an empirical evaluation in terms of power and type‐I error rate of the of the weighted log‐rank test in a simulated scenario with fixed values of the Fleming and Harrington class of weights. We also give some practical recommendations regarding which methodology should be used in the presence of delayed effects depending on certain characteristics of the trial.     

高校德育低效的内因分析

高校德育低效除社会大环境的负面影响外,高校德育自身的问题也不可忽视。智德分离;不尊重学生的主体地位;忽视培育和发展学生的情感、忽视学生的差异和个性;德育与学生的生活和需要脱节;育德者的人格不适应德育的要求等德育自身的缺陷是德育低效的内在原因。     

立足高起点发展新方向培养应用型复合型人才——对我院法学专业教学的认识及建议

我院法学专业培养目标是为社会培养应用型、复合型人才 ,针对实际情况 ,作者提出应改革教学内容 ,优化课程体系 ;改革教学方法 ,完善教学手段 ;提高教师业务水平 ,加强学术梯队建设等建议。     

孔子的富贵观及其现代价值解读

孔子的富贵观是其思想体系的重要组成部分。孔子关于世人应否追求富贵,怎样处理富贵与道义的关系,以及富裕之后还当如何等问题在《论语》中都有论述。孔子的这些论述,对当代人们创业致富,以义求利,以及坚持经济建设与精神文明建设两手抓,仍然具有启迪作用和借鉴价值。     

论审美理念系统的价值阶位

审美理念系统,以其特有的知识形式反映着人类审美价值的阶位需求。文中论述了人类最有代表性的五种阶位需求,认为虽然它们都反映一定的审美本质,但从生命与价值超越角度考虑,它们的内在思想特色和精神追求,还存在着很大的区别。     

Uncertainty Analysis for Computer Model Projections of Hurricane Losses

Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.     

1000VMOSFET用常规低压工艺的实现

采用常规低压集成电路工艺实现了耐压达１０００Ｖ的高压横向ＭＯＳＦＥＴ，详细介绍了该高压横向ＭＯＳＦＥＴ的设计方法、器件结构、工艺技术及测试结果。文中从实验和分析的角度上首次探讨了覆盖在漂移区上面的金属栅长度对该高压横向ＭＯＳＦＴ击穿电压的影响。     

低层次产业对智力的挤出效应

低层次产业对解决低技术劳动力就业有益，但对智力资源扣科教基本设施却会带来损害。本文探讨产业发展和教育发展的关系．着重探讨低层次产业对智力资源和设施的国际挤出效应，地区挤出效应和本地挤出效应。本文同时指出低层次产业尽管对智力存在负面效应，但不应该因此否定它，并且提出在我国产业布局和地方经济发展中应遵循梯度转移的规律，谨防欠发达区低层次产业发展对智力挤出的同时对收入也形成挤出，谨防发达区因为产业层次不高对智力形成挤出．谨防欠发达区盲目发展高层次产业对低技术劳动力形成驱赶等政策建议。     

Who Gets What From Government? Distributional Consequences of Child‐Care Assistance Policies

Given the fragmented structure of child‐care assistance in the United States, it has been difficult to obtain accurate estimates of which families are assisted, through which mechanisms, and at what level. Making use of survey data from New York City, we analyze the distribution of several forms of public child‐care assistance. Results suggest that about 40% of all families with young children receive some form of child‐care assistance. Considering all forms of assistance, the distribution of child‐care help is targeted in both expected and some unexpected ways. Implications of these results are discussed in the context of U.S. child‐care policies governing access and benefit levels.     

板栗干枯病的低温防治初探

在冬季低温条件下,用40%腐烂敌80倍液及其它药剂对板栗干枯病进行病部涂抹防治,用白色塑料薄膜包严。调查不同处理时期的防治效果发现,以11月22日腐烂敌处理效果最佳,病部复发率最低(为零),为板栗干枯病的有效防治提供了科学依据。