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。     

花岗岩储层损害机理及保护技术研究

花岗岩储层由于岩性、物性、孔隙结构和敏感性矿物特征与常规储层有一定的差异，所以其损害机理也与常规储层不尽相同。本次研究利用扫描电镜、铸体薄片等手段，系统分析了花岗岩储层的损害机理，并对其有效的储层保护措施进行了探讨。研究结果表明：花岗岩储层主要的损害机理为固相侵入、应力敏感性损害和水锁损害，“五敏”损害中水/盐敏、碱敏损害较弱，主要为酸敏和速敏损害。研究认为欠平衡钻井技术是开发花岗岩储层的最佳选择，将欠平衡钻井与非直井工艺相结合可穿越储层中多条裂缝，获得更佳的产能；低压屏蔽暂堵技术虽然难以解决储层中宏观缝、大缝的封堵问题，但可以有效封堵储层中小于50μm的裂缝，使部分产能得到保护     

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.     

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.     

Hypothesis Testing in a Rayleigh Diffusion Model

Applying the large and moderate deviations for the log-likelihood ratio of the Rayleigh diffusion model, we give the negative regions in testing Rayleigh diffusion model and obtain the decay rates of the error probabilities.     

朝阳民间刺绣：遗留在深山的“珍珠”

一项项民间技艺如一颗颗美丽的珍珠,散落在乡野间的每个角落,经过岁月的打磨,散发出温润的光泽.而作为非遗工作者,就是那些采撷珠宝的人,要将它们一一串联,使其绽放更为动人的夺目光彩.2013年的初夏,我和同事们来到朝阳,找寻那颗遗留在深山里的珍珠——朝阳民间刺绣.     

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。