Testing homogeneity in semiparametric mixture case–control models

Parametric and semiparametric mixture models have been widely used in applications from many areas, and it is often of interest to test the homogeneity in these models. However, hypothesis testing is non standard due to the fact that several regularity conditions do not hold under the null hypothesis. We consider a semiparametric mixture case–control model, in the sense that the density ratio of two distributions is assumed to be of an exponential form, while the baseline density is unspecified. This model was first considered by Qin and Liang (2011 Qin, J., Liang, K.Y. (2011). Hypothesis testing in a mixture case–control model. Biometrics 67(1):182–198.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar], biometrics), and they proposed a modified score statistic for testing homogeneity. In this article, we consider alternative testing procedures based on supremum statistics, which could improve power against certain types of alternatives. We demonstrate the connection and comparison among the proposed and existing approaches. In addition, we provide a unified theoretical justification of the supremum test and other existing test statistics from an empirical likelihood perspective. The finite-sample performance of the supremum test statistics was evaluated in simulation studies.     

经济增长与日照减少:源自广东的实证研究

过去30年中国经济发展所取得的成绩举世瞩目,但生态环境污染日趋加剧亦成为不争的事实.作为中国现代化的缩影,1980-2010年,广东每增加1％的工业产值,日照时间减少0.3852小时.抽样调查的结果显示:目前广州、深圳等珠三角城市的日照时数已降至接近公众期望的临界值.遏制此种态势,转变经济发展模式固然重要,但更为重要的在于物欲的“零增长”.要做到这一点,日照时数应成为政府环保绩效评价的重要指标.     

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.     

浅析里克纳家庭品格教育理论及其启示

本文对里克纳《美式家庭:品质教育家长对策》一书阐述的理论及其启示加以论述。     

A transnational networked public sphere of air pollution: analysis of a Twitter network of PM2.5 from the risk society perspective

ABSTRACT

Drawing on digitaltrace data, publicly accessible government documents, and journalistic reports, this research integrates Beck’s risk society theory with digital media theories to examine the mediated process of risk definition and assessment of PM2.5 (particulate matters with a diameter less than 2.5 micrometers) in a networked public sphere. Network and content analysis of a PM2.5 Twitter network shows that political and professional elite remained the most powerful producers of risk definition. Established media played a key role, yet faced challenges from a variety of actors who disseminated and filtered information. Laypersons, while peripheral, actively interacted with elite and established media. The blurring geographic boundary in the PM2.5 Twitter network revealed an emerging transnational public sphere, which, however, was segregated by language. This research advances a layered understanding of the contingent, paradoxical media impact for social changes in a risk society.     

Stereotype and National Attachment in Hong Kong Chinese Context: A Moderated Mediation Model of Perceived Inter-group Relationship and Age

The present study investigated the relationship between Hong Kong people’s stereotype toward Mainland people and their own national attachment (i.e., national identity, constructive patriotism, and uncritical patriotism). The role of inter-group relationship as mediator and age as moderator of that relationship were also tested. A total of 1753 local Hong Kong people aged 17–80 (mean age = 20.35 years, SD = 5.02) completed anonymous questionnaires regarding their stereotypes toward Mainland people, inter-group relationship with Mainland people, and national attachment. As expected, stereotypes toward Mainland people, inter-group relationship and national attachment showed significant positive associations with each other. More interestingly, it was found that the inter-group relationship mediated the relationship between stereotypes toward Mainland people and three domains of national attachment, with this indirect link being weaker for younger Hong Kong adults than for older Hong Kong adults. Implications of the present findings for future research are discussed, as well as potential interventions for increasing subjective national attachment to China, especially in young Hong Kong people.     

边塞与闺情的结合——论纳兰容若边塞词的艺术个性

纳兰容若边塞词在词史上是独特的存在,塞外风物与闺中情愫的巧妙结合,边塞题材与婉约词性的完美统一,显示了纳兰容若卓绝的艺术个性。这源于其独特的人生经历和对情的特殊体认。纳兰对情的体认和表述,受晚明重情、任情的文学观念的影响,词中在乎的是情的充分表达,而不注重边塞景物的猎奇性描写。纳兰词把闺情的叙写置于边塞词的核心,把边塞景物作为情感表现的背景,从而在传统的边塞词领域开拓出新的气象。     

Cities evolution tree and applications to predicting urban growth

China’s unprecedented urbanization and economic modernization have brought about significant growth and land use changes in cities and their surroundings. Traditional analyses of the relationship between urbanization and land use change have not fully incorporated important factors like city function or developmental stage. We define and apply a new visualization and analysis tool—an evolution tree—showing how an understanding of evolutionary pathways taken by growing cities contributes to visualization and forecasting of urban development and spatial expansion. We clustered 253 Chinese cities by type and developmental stage, arranging them in a “tree” structure, with types grouped as branches and leaf position along branches reflecting developmental stage. Urban growth rates are higher for business-oriented, manufacturing-oriented, and functionally comprehensive cities than for those oriented toward tourism. Extent of spatial growth is dominated by city type and developmental stage. Cities evolve along typical pathways, punctuated by occasional leap developments across functional types.     

积分变换求梁的变形

本文从求解梁挠度的二阶差分方程出发，通过Z变换，最后推导出计算挠度和转角的简单公式，使计算过程简化。对于变截面梁和复杂受载下，此法尤为简便。同时，这也是处理离散参数的数学方法—Z变换在力学中应用的初步尝试。     

关于学科教材语言研究问题的思考——以数学教材语言研究为例

学科教材是公民科学素养教育的基础和依据.数学是最重要的基础学科,对数学教材语言的研究,不仅有助于数学教材的编写和评价,且有助于其他学科教材语言的研究,有助于学科教育质量的提高.文章分析了数学教材语言的领域特征,介绍了数学语言表述特征及其对数学教育的影响,并对数学语言中的字符、词及词组、语法结构与专用表达等表述单位的特点进行了分析归纳.语料库技术是语言研究取得系统化、科学、可靠结论的基础.文章还介绍了数学教材语言语料库建设的原则和过程.本研究认为,叙述语言是学科知识的翻译、解释和陈述系统,对其表述特征和习惯的调查分析,有助于提高教材的编写质量,进而促进学生学科知识的获取和学科能力的提高,因此,应该加大力度,对学科教材语言特征进行专门研究.