Partitioned log-rank tests for the overall homogeneity of hazard rate functions

In survival analysis, it is routine to test equality of two survival curves, which is often conducted by using the log-rank test. Although it is optimal under the proportional hazards assumption, the log-rank test is known to have little power when the survival or hazard functions cross. To test the overall homogeneity of hazard rate functions, we propose a group of partitioned log-rank tests. By partitioning the time axis and taking the supremum of the sum of two partitioned log-rank statistics over different partitioning points, the proposed test gains enormous power for cases with crossing hazards. On the other hand, when the hazards are indeed proportional, our test still maintains high power close to that of the optimal log-rank test. Extensive simulation studies are conducted to compare the proposed test with existing methods, and three real data examples are used to illustrate the commonality of crossing hazards and the advantages of the partitioned log-rank tests.     

近代中国铁路货等运价制度变迁初探(1915—1937)

由于货等运价制度直接与铁路营业收入挂钩,因此成为铁路运营管理制度的核心内容之一。1915年之后,在交通部(铁道部)和各铁路管理局(监督局)的共同努力下,以货物分等、递远递减、普通货物基本运价、专价和特价制度为主要内容的铁路货等运价制度逐渐走向统一。尽管这一过程在1937年前并未最终完成,但其变迁仍然对铁路运输业和沿线部分城镇的发展产生了重要的影响。     

我国民法基本制度生态化探究

生态文明时代要求法律制度进行不同程度的生态化.在各种法律制度生态化历程中,民法制度的生态化起着相当重要的作用.民法基本制度的生态化是民法生态化的重要内容,它包括人格权制度的生态化、物权制度的生态化、合同制度的生态化、侵权责任制度的生态化.这其中,环境人格权是人格权制度生态化的主要内容；生态性用益物权是物权制度生态化的重要组成部分；环境物权交易合同是合同制度生态化的主要方面.以损害风险预防、现实损害救济赔偿、恢复责任承担为切入点,采用无过错责任与过错加重责任并用的原则,贯彻环境损害全程监管与责任追究的理念,对环境污染与生态破坏的源头与过程实行全面的控制与追责是侵权责任制度生态化的基本要素.     

Do resources of network members help in help seeking? Social capital and health information search

Does social capital as resources of network members affect health information search? Analyzing data from the 2004 General Social Survey in the United States, this study measures two social capital indicators (average education of network members and proportion of network members with a high school degree or higher) using the name generator. Most results are consistent using those two indicators. Both indicators are positively associated with frequency of health information seeking and seekers’ frequency of use of two sources (friends or relatives and the Internet). Also average education of network members is positively associated with seekers’ diversity of used sources and frequency of consultation with medical professionals. But neither indicator is associated with seekers’ frequency of use of other four sources (health-related magazines or newsletters, general magazines, daily newspapers, and radio or television programs). The findings demonstrate the theoretical utility of social capital in the social dynamics of medical help-seeking.     

Communicating Conservation Status: How Different Statistical Assessment Criteria Affect Perceptions of Extinction Risk

Although alternative forms of statistical and verbal information are routinely used to convey species’ extinction risk to policymakers and the public, little is known about their effects on audience information processing and risk perceptions. To address this gap in literature, we report on an experiment that was designed to explore how perceptions of extinction risk differ as a function of five different assessment benchmarks (Criteria A–E) used by scientists to classify species within IUCN Red List risk levels (e.g., Critically Endangered, Vulnerable), as well as the role of key individual differences in these effects (e.g., rational and experiential thinking styles, environmental concern). Despite their normative equivalence within the IUCN classification system, results revealed divergent effects of specific assessment criteria: on average, describing extinction risk in terms of proportional population decline over time (Criterion A) and number of remaining individuals (Criterion D) evoked the highest level of perceived risk, whereas the single‐event probability of a species becoming extinct (Criterion E) engendered the least perceived risk. Furthermore, participants scoring high in rationality (analytic thinking) were less prone to exhibit these biases compared to those low in rationality. Our findings suggest that despite their equivalence in the eyes of scientific experts, IUCN criteria are indeed capable of engendering different levels of risk perception among lay audiences, effects that carry direct and important implications for those tasked with communicating about conservation status to diverse publics.     

长三角创新资源的空间错配与调整政策——基于次级和县级区域的实证研究

依据对长江三角洲次级和县级区域资源配置现状的实证研究发现：一是长江三角洲区域在经历高速重化工业化的同时，开始跨入了内生增长模式的门槛，人力资本的贡献日益显现；二是越来越多的次级区域工业生产能力和技术创新能力正在超越北京、上海以及省会城市，由此国家的科技资源和高等教育资源也应当流向这些区域，使产业、科技、教育资源能够融合在同一个空间，以大大提高整个国家技术创新投入的收益；三是转变经济发展方式和实施创新型国家建设战略的真正落脚点是支持和推动更多的次级和县级区域建立高等教育体系，创造更多的人力资本，开展更多的技术创新活动，使更多的区域采取基于技术进步的增长战略。充足的证据表明，现在到了需要采取一个重视创新资源效率的区域增长战略的时候了。     

信贷歧视、青年创业群体与互保信贷模式

通过构建一个基于互保制度不存在情况下的银行信贷选择的理论模型,揭露银行对于青年创业者的信贷偏向.进而建立一个基于随机组合情况下的互保信贷模型,发现随机组合的互保机制反而不如普通信贷模式.运用此理论模型重点分析欺诈不存在和存在的互保信贷机制,得出如下的结论:创业者欺诈意愿不存在的情况下,银行给优质小组和混合小组的借贷成本应该让他们项目的经济利润近似于零,违约连带还款额接近投资项目的总收益.创业者欺诈意愿存在的情况下,在具有完善的合作约束和激励约束的前提下,银行应该对任一创业群体互保小组一视同仁,给予相同的贷款利率.同时,一旦小组成员违约,银行对承担责任的创业者抽贷行为不应该出于惩罚目的.     

Bayesian estimation of rare sensitive attribute

Randomized response models have been used to estimate a population proportion of a sensitive attribute. A randomized device is typically employed to protect respondent's privacy in a survey. In addition, an unrelated question is asked to improve the statistical efficiency. In this article, we propose Bayesian estimation of rare sensitive attribute using randomized response technique, which includes a rare unrelated attribute. Two cases are considered, the proportion of a rare unrelated attribute is known and unknown. A simulation study is conducted to assess the performance of the models using mean absolute error and coverage probability. The results show that the performance depends on the parameters and is robust to priors.     

Precise large deviations for the difference of two sums of END random variables with heavy tails

Assume that there are two types of insurance contracts in an insurance company, and the ith related claims are denoted by {X_ij, j ? 1}, i = 1, 2. In this article, the asymptotic behaviors of precise large deviations for non random difference ∑^n₁(t)_{j = 1}X_1j ? ∑^n₂(t)_{j = 1}X_2j and random difference ∑^N₁(t)_{j = 1}X_1j ? ∑^N₂(t)_{j = 1}X_2j are investigated, and under several assumptions, some corresponding asymptotic formulas are obtained.     

技术与制度交互视角下建筑企业绿色转型驱动的内生机理研究

基于技术与制度交互理论,利用扎根理论识别出15项影响建筑企业绿色转型的内生性因素,采用ISM-MICMAC方法探索影响因素间的作用机理。结果表明,技术与制度相互影响、协同促进建筑企业绿色转型内生驱动力的形成。市场调研、项目管理、财务能力是推动绿色转型的直接因素,也是内生性驱动因素。