On Confounding, Prediction and Efficiency in the Analysis of Longitudinal and Cross-sectional Clustered Data

Abstract.  In the analysis of clustered and/or longitudinal data, it is usually desirable to ignore covariate information for other cluster members as well as future covariate information when predicting outcome for a given subject at a given time. This can be accomplished through con-ditional mean models which merely condition on the considered subject's covariate history at each time. Pepe & Anderson (Commun. Stat. Simul. Comput. 23, 1994 , 939) have shown that ordinary generalized estimating equations may yield biased estimates for the parameters in such models, but that valid inferences can be guaranteed by using a diagonal working covariance matrix in the equations. In this paper, we provide insight into the nature of this problem by uncovering substantive data-generating mechanisms under which such biases will result. We then propose a class of asymptotically unbiased estimators for the parameters indexing the suggested conditional mean models. In addition, we provide a representation for the efficient estimator in our class, which attains the semi-parametric efficiency bound under the model, along with an efficient algorithm for calculating it. This algorithm is easy to apply and may realize major efficiency improvements as demonstrated through simulation studies. The results suggest ways to improve the efficiency of inverse-probability-of-treatment estimators which adjust for time-varying confounding, and are used to estimate the effect of discontinuing highly active anti-retroviral therapy (HAART) on viral load in HIV-infected patients.     

劳动力社会关系网络构建的新视角

目前我国城乡居民收入差距不断扩大,户籍制不断松动,为市场劳动力流动创造了条件.按照经典经济理论,应有很多贫困地区劳动力将迁移出来.但这点与实际却有许多不同.笔者认为社会资本特别是社会关系网络不完善,成为阻碍其流动的重要原因.并就此问题用微观分析的方法进行研究,得出农民个体很难对社会资本进行投资.完善劳动力市场机制,要求地方政府必须成为农民个体的代言人,来为其构建和完善社会关系网络,以保障劳动力迁移处于良性运行轨道.     

再论包容式衍推

对诸多命题进行考察,发现很多相异部分具有"上下位关系"的命题并不能够进行包容式衍推。在此基础上指出:必须强化这样的认识,即上下位关系不能简单地等同于两个命题中相异词语是上下位词或两个词语在词义上具有整体和部分的包含关系,它应该是指命题与命题之间的包含关系;应当取消语法受定衍推和包容式衍推的界限,打通这两种衍推类型,在解释衍推问题时就能减少诸多麻烦。     

Semiparametric Mixtures of Generalized Exponential Families

Abstract.  A semiparametric mixture model is characterized by a non-parametric mixing distribution Q (with respect to a parameter θ ) and a structural parameter β common to all components. Much of the literature on mixture models has focused on fixing β and estimating Q . However, this can lead to inconsistent estimation of both Q and the order of the model m . Creating a framework for consistent estimation remains an open problem and is the focus of this article. We formulate a class of generalized exponential family (GEF) models and establish sufficient conditions for the identifiability of finite mixtures formed from a GEF along with sufficient conditions for a nesting structure. Finite identifiability and nesting structure lead to the central result that semiparametric maximum likelihood estimation of Q and β fails. However, consistent estimation is possible if we restrict the class of mixing distributions and employ an information-theoretic approach. This article provides a foundation for inference in semiparametric mixture models, in which GEFs and their structural properties play an instrumental role.     

先秦儒家在人际关系问题上的内在矛盾及其中庸之道

先秦儒家关于人际关系问题的论述存在着明显的内在矛盾。为此他们提出中庸之道以协调、解决这一矛盾。故中庸之道对先秦儒家具有极其重要的方法论意义。忽略、抹杀这一点，也就阉割了先秦儒家的基本精神。     

英语介词of的语义、修辞功能

of是英语的一个重要虚词,在应用中随处可见,它又与其他实词构成许多习语性短语。其用法多而杂,给外语学习者带来了很多的困难。因而,有必要从新的角度———语义角度加以梳理。其丰富的修辞功能尚未系统开发,需要外语学习者对它进行专门研究,在写作翻译过程中更好地理解应用它。     

动量词"遍"的语义探讨

语法学界对动量词"遍"遍指义的概括存在简单化倾向,通过对"遍"的遍指义进行深入分析,可以将其分为四类:对象性周遍、过程性周遍、伴随性周遍和转指性周遍。本文还对各遍指义对动词的语义选择以及遍指范畴的扩展过程进行了探讨。     

保辜制度的医学法律思想价值

保辜制度是我国古代特有的刑事法律制度之一，我们可以从两方面挖掘其深刻的医学法律思想价值：一方面，应以谦卑审慎的态度对待医法关系，尽可能发挥二者的作用，促进司法鉴定问题和医患纠纷的协调解决；另一方面，强调加害人对被害人的救冶义务应包括医学心理学方面的效果，这是该制度所蕴涵的内容之一。     

企业文化构建中的“两点论”——对绍兴餐饮文化建设的反思

对企业文化建设,既要重视,又要有科学的方法.绍兴餐饮业作了有益尝试,他们在打造诚信、人本、品牌、创新四大经营理念时,从剖析餐饮业及各企业特有的经营关系,运用两点论,把四大经营理念分别应用到对立统一的各种层面中,取得双赢效果,推动了经营矛盾的解决,拓展了四大经营理念的应用空间.文章在调查了绍兴十家中型宾馆、饭店基础上,对此进行梳理.     

论房地产业过热对推进城市发展的不利影响

城市发展需要各产业的协调发展,任何产业的过度发展都不利于城市竞争力的提升和整体发展。当前我国房地产市场呈现出过热态势,这一态势对城市发展产生了一定的负面影响,主要是导致城市产业结构出现失衡、不利于建设和谐城市、不利于城市合理规划,同时也削弱了城市的整体竞争力,进而抑制城市化进程。对此,各方要采取有力措施调控房地产市场,实现房地产业与整体经济的协同发展。