Inferences on the Means of Two Log-Normal Distributions: A Computational Approach Test

In this article, we propose a novel approach for testing the equality of two log-normal populations using a computational approach test (CAT) that does not require explicit knowledge of the sampling distribution of the test statistic. Simulation studies demonstrate that the proposed approach can perform hypothesis testing with satisfying actual size even at small sample sizes. Overall, it is superior to other existing methods. Also, a CAT is proposed for testing about reliability of two log-normal populations when the means are the same. Simulations show that the actual size of this new approach is close to nominal level and better than the score test. At the end, the proposed methods are illustrated using two examples.     

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.     

Blinded continuous monitoring in clinical trials with recurrent event endpoints

In studies with recurrent event endpoints, misspecified assumptions of event rates or dispersion can lead to underpowered trials or overexposure of patients. Specification of overdispersion is often a particular problem as it is usually not reported in clinical trial publications. Changing event rates over the years have been described for some diseases, adding to the uncertainty in planning. To mitigate the risks of inadequate sample sizes, internal pilot study designs have been proposed with a preference for blinded sample size reestimation procedures, as they generally do not affect the type I error rate and maintain trial integrity. Blinded sample size reestimation procedures are available for trials with recurrent events as endpoints. However, the variance in the reestimated sample size can be considerable in particular with early sample size reviews. Motivated by a randomized controlled trial in paediatric multiple sclerosis, a rare neurological condition in children, we apply the concept of blinded continuous monitoring of information, which is known to reduce the variance in the resulting sample size. Assuming negative binomial distributions for the counts of recurrent relapses, we derive information criteria and propose blinded continuous monitoring procedures. The operating characteristics of these are assessed in Monte Carlo trial simulations demonstrating favourable properties with regard to type I error rate, power, and stopping time, ie, sample size.     

城市综合体建设面临的一系列问题探讨--以南通市为例

随着房地产调控和城市化进程的加快，商业地产越来越受到开发商的青睐。城市综合体作为商业地产的典型代表以其多结构多层级的功能组合迅速提升区域价值而拥有了“城中之城”的美誉，在东部地区二三线城市大量涌现。但城市综合体带动城市发展的同时，也引发了一系列风险亟待关注。     

Modifications of sequential designs in bioequivalence trials

Bioequivalence (BE) studies are designed to show that two formulations of one drug are equivalent and they play an important role in drug development. When in a design stage, it is possible that there is a high degree of uncertainty on variability of the formulations and the actual performance of the test versus reference formulation. Therefore, an interim look may be desirable to stop the study if there is no chance of claiming BE at the end (futility), or claim BE if evidence is sufficient (efficacy), or adjust the sample size. Sequential design approaches specially for BE studies have been proposed previously in publications. We applied modification to the existing methods focusing on simplified multiplicity adjustment and futility stopping. We name our method modified sequential design for BE studies (MSDBE). Simulation results demonstrate comparable performance between MSDBE and the original published methods while MSDBE offers more transparency and better applicability. The R package MSDBE is available at https://sites.google.com/site/modsdbe/ . Copyright © 2015 John Wiley & Sons, Ltd.     

论全球气候治理中城市的角色转型——兼论中国困境与出路

从全球气候治理的1.0时期、2.0时期到3.0时期，城市逐渐实现了从“幕后参与者”到“共同引领者”的角色转型。这一转型既得益于全球治理理论在气候变化领域的延伸，更受惠于城市外交理论的推动和全球气候治理中“集体行动的困境”之驱使。就目前来看，中国城市的这一“共同引领者”角色还无法完全体现出来——不仅在隐性的“南北分割”的权力结构和发展中国家的气候治理分歧中，面临着对外发展的困境；而且在中央政府对地方政府的气候治理行动的“单向”型构造及城市的“经济发展”和“治理责任”的两难抉择中，面临着对内优化的瓶颈。针对这些问题，中国可以采取“两条干路+六条支路”的“两轨并行”式路径来寻求合理的应对之策。国家可以在寻求发展中国家的集体身份认同之时，进一步完善国内温室气体减排政策和立法，并赋予城市以一定的自主性；而城市也可以在深化城市气候外交，加强与国家的“双向”型气候治理互动的同时，推动“韧性城市”的长效发展。     

常德市土壤水分平衡指标定量计算研究

土壤水分平衡指标是衡量某一区域土壤水分状况的重要标志，正确掌握某一区域的土壤水分平衡指标．有利于该区农业生产的合理布局和各种农作物的合理配置。定量计算表明：常德市的几种主要土壤水分平衡指标为：年可能蒸散量Ep919mm，年实际蒸散量E．906mm，土壤年缺水量D13mm，土壤年余水量R473mm。通过对常德市全年土壤水分收支情况的分析，得到了较为满意的结果，为有关方面提供了借鉴材料。     

城市道路交通问题与对策探讨

从中国大城市交通堵塞现象着手,研究了机动车辆的增加与道路通行能力的关系,以及机动车迅速增长所带来的环境污染问题,分析了问题产生的原固及其危害程度,探讨改善城市交通的途径和解决的方案,提出适当限制个人轿车,积极发展轨道交通,规划建设中心网络城市的现点。     

从招赘婚姻看城郊农民市民化:以萧山 R村为例

近几年来,浙江城郊农村撤村建居过程中招赘婚姻比例上升。本文阐释这类现象背后的行动逻辑,即招赘婚姻的正功能,以及可能给农民市民化带来的负面效应,由此呈现农民市民化的复杂性。     

关于建立“成都学”的思考

通过一个城市的历史,去透视整个人类文明发展的进程、值得趋避的经验与教训,是城市学研究的根本目的.把具有两千多年历史的成都作为一个聚焦点,可以涉猎城市规模、城市生态系统、社会结构和社会文化,以及地理、历史、人才、经济、技术,城市管理机制、生态机制、监督机制和应变机制等诸多问题,这也都是当今世界性"城市化"浪潮中人们普遍关心的话题.