Reducing sample size needed for cox-proportional hazards model analysis using more efficient sampling method

Abstract

In general, survival data are time-to-event data, such as time to death, time to appearance of a tumor, or time to recurrence of a disease. Models for survival data have frequently been based on the proportional hazards model, proposed by Cox. The Cox model has intensive application in the field of social, medical, behavioral and public health sciences. In this paper we propose a more efficient sampling method of recruiting subjects for survival analysis. We propose using a Moving Extreme Ranked Set Sampling (MERSS) scheme with ranking based on an easy-to-evaluate baseline auxiliary variable known to be associated with survival time. This paper demonstrates that this approach provides a more powerful testing procedure as well as a more efficient estimate of hazard ratio than that based on simple random sampling (SRS). Theoretical derivation and simulation studies are provided. The Iowa 65+ Rural study data are used to illustrate the methods developed in this paper.     

市场分割、政企关系与异地市场拓展

中国的市场仍旧存在某种程度的分割，如何突破这种市场分割到异地拓展市场是企业要考虑的现实问题。以前的研究主要是从省级层面或国家层面进行宏观分析。文章创新地从政企关系视角入手来考察市场分割情形下微观层面的企业异地市场拓展，也是首先把市场分割（和异地市场）分为省内（本市外）市场、省外市场和海外市场三个不同层面来研究的论文。用世界银行的调查数据从微观企业个体层面检验了企业异地市场拓展的可能。实证研究结果发现，市场分割确实阻碍了企业异地市场拓展，但这仅限于省内市场而不是省外市场。此外，市场分割是有方向性的，从地方保护主义严重的市场里走出来的企业更容易拓展异地市场，但此结论仅适用于国内市场拓展而不适用于海外市场拓展。良好的政企关系是有利于企业异地市场拓展的，但仅限于省外市场，对省内市场以及海外市场是无效的。文章解释了其中的原因，并分析了对于企业实践的启示。     

论历史演义的虚构性

明清时期对历史演义的性质存在着争议,有些评论家认为历史演义是正史的通俗版,因而极力反对在历史演义中进行虚构。但大量的创作实践证明,为了增强作品的可读性,历史演义不可能句句依傍正史,必然在细节描写、心理刻画、语言描写、环境烘托等方面进行虚构,从而使历史演义成为虚实结合的历史小说。     

乡约的诸属性及其文化原理认识

乡约是传统社会乡民基于一定的地缘和血缘关系,为某种共同目的而设立的生活规则及组织。乡约最初形成于中国,后传播至朝鲜半岛、日本和越南,成为东亚社会共同的法律文化传统。传统中国的乡约有其时空性、价值性和法律性。乡约不是国法,但在乡民的实际生活中发挥着法的作用,是中国传统社会秩序构造链中的重要一环,其内贯一极二元主从式多样化的文化原理,与传统中国社会的结构和文化理念相契合。近代以来,乡约总体上呈现出消解的趋势,但至今仍有各种流变形式,认真对待,合理改造,必有益于中国类型法治社会的建立。     

加快郑州商贸城建设提高经济辐射力

近来年,在郑州商贸城的发展过程中出现了一些问题,商贸城建设步伐有放慢的倾向.为了更好地发挥郑州中心城市的经济辐射带动作用,就必须采取相应措施,如加快城市化进程和商贸城建设、优化产业结构、加快卫星城市建设等.     

Editor's Note: What,Exactly, Is the Purpose of a Book Review?

Qualitative Sociology -     

Racial Differences in Abused Older African American Males, Caucasian Males, and their Abusers

This study examined racial differences between mistreated and abused older African American and Caucasian men. The racial and gender differences of their perpetrators were also examined. Data from a single elder abuse provider agency in the State of Illinois were analyzed. Differences with respect to physical abuse, emotional abuse, physical neglect, deprivation, confinement, and financial exploitation were examined, as were demographic characteristics and limitations of victims and abusers.     

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 .     

腔内电光调制激光系统的混沌模拟

采用数值模拟的方法讨论了带反馈的腔內电光调制激光系统功率输出的分叉和混沌行为,得到了输出功率随控制参数变化的分叉图,和一些定量结果。