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.     

政府减排目标、产业结构与污染减排

政府是污染减排的重要主体,了解其行为对污染减排的作用对提升污染减排效果及实现中国绿色发展具有重要意义。创造性地将政府减排目标纳入研究框架,构建面板门槛模型,从工业污染排放总量的角度分析政府减排目标、产业结构、经济规模等因素对地方污染减排的影响,并用工业污染物强度进行稳健性检验。结果显示,政府减排目标对污染减排的作用存在阶段性不同:经济发展初级阶段,政府减排目标对污染排放总量的作用方向为正; 经济发展水平较高时,作用方向为负; 两者之间存在适应性调整阶段,作用方向具有不确定性,但总体由正向作用向负向作用转变。产业结构对工业污染排放总量的作用方向因污染物种类而异,经济规模对工业污染排放总量作用方向为正。     

区块链技术在版权登记中的创新应用

随着数字版权时代的发展，作品的传播方式变得更加灵活，传播速度也更加迅捷。传统版权登记制度因存在登记成本较高、标准不一、泄露隐私等弊端，在实际应用中面临困境，区块链技术的出现为推动版权登记的适时发展提供了一种新思路。区块链技术应用于版权登记，其去中心化特质可以降低登记成本；分布式共享机制能够统一登记标准；难以篡改的性质能够提高登记的证明效力；弥补了既有版权登记制度的缺陷。同时，区块链技术利用自身特性建立新的版权信任机制，既能清晰地分配版权利益，又能创新传统的版权商业模式，推动版权市场的发展，最大化地利用版权的固有价值。区块链技术在与版权登记相结合的过程中，会出现一些技术上难以解决的问题，既无法对作品的独创性进行准确的判断，也无法发挥版权制度原有的公示力作用。因此，必须创新版权登记规则，加快制定区块链版权平台市场准入机制，并设置统一的监管机构，将区块链锁在版权制度的笼子里，防止出现滥用区块链技术的情形，以最终实现技术和法律的融合发展。     

娄底市实现农业和农村可持续发展的探索

可持续农业和农村发展”(SARD)是联合国粮农组织倡导的世界未来农业和农村发展的大趋向。本文探究了可持续农业和农村发展的内涵及来源 ;立足娄底地情 ,分析了其农业和农村可持续发展中存在的问题 ;提出了实现娄底可持续农业和农村发展的目标和对策     

发展是反贫困的核心问题--广西百色反贫困研究之三

发展是反贫困的主题。发展是解决贫困问题的关键。必须用加快发展的办法解决贫困问题。     

学校领导干部的自我发展素质及培养

自我发展素质是学校领导干部综合素质的重要组成部分 ,它反映了社会发展、领导职位和人的本性发展的要求。形成学校领导干部自我发展素质的主要方式是干部培训和教育实践中的探索与反思     

Middle School Children's Perceptions on Welfare and Poverty: An Exploratory, Qualitative Study

This study was undertaken to determine how middle school children assess the effects of welfare reform on their daily lives. The study consisted of thirty interviews with children and their mothers recruited from a middle school in a large, metropolitan area. From the children's perspective, multiple jobs and evening/night hours interfered with the child-parent relationship. Other consequences included grades going down and not getting to school on time. All the children stated that mothers should work, but most children felt mothers should only work when their children are in school. Welfare and poverty were issues about which children were teased at school.     

The University: An Agent of Social Change?

Can universities be agents of progressive social change? How would we know if a university was acting as an agent of social change? Drawing on four case studies, I raise a number of questions to problematize our understanding of the university as an agent of social change. I outline a number of contributing factors that appear to explain successful cases. I conclude by arguing the relevancy of these cases for larger, and more traditional, sociological projects.     

三国时期西部农业开发述论

三国时期 ,曹魏控制西北 ,蜀汉占据西南 ,两国主要在西部地区争战 ,粮草供给成为决定胜负的关键因素 ,为此双方都采取了恢复和发展粮食生产的措施。曹魏在西部一些适宜农业的战略要地大兴屯田 ,开发关陇、稳定河西 ,每年收获大量谷物供给军粮 ,以守为攻 ,迎战蜀军 ;蜀汉占据西南之后 ,诸葛亮注意处理好民族关系 ,发挥当地的农业资源优势 ,劝农积谷。为了解决北伐运粮的困难 ,还在汉中及渭水南岸一些地区设置少量屯田。不同的农业开发措施与双方的治乱胜败有很大关系。     

谈新教师的角色投入

新教师要树立正确的角色意识 ,培养深厚的角色情感 ,锻炼角色耐受挫折的能力 ,养成角色的文明行为习惯 ,加强角色的反思和更新 ,以促进角色的成熟和发展