Choice Functions: Rationality re-Examined

On analyzing the problem that arises whenever the set of maximal elements is large, and a selection is then required (see Peris & Subiza 1998), we realize that logical ways of selecting among maximals violate the classical notion and axioms of rationality. We arrive at the same conclusion if we analyze solutions to the problem of choosing from a tournament (where maximal elements do not necessarily exist). So, in our opinion the notion of rationality must be discussed, not only in the traditional sense of external conditions (Sen 1993), but in terms of the internal information provided by the binary relation.     

试论继续教育对教师素质的现代转换

继续教育是我国为实现现代化尤其是教育现代化、人的现代化所进行的新型教育。本文从知识经济与教育现代化的背景上论述了继续教育对教师素质进行转换的必要性、基本内涵、基本内容以及转换的方向。     

论当代中国政府经济职能的战略性重构

政府经济职能战略性重构的内涵是 :防止、纠补“政府失灵”和克服、弥补“市场失灵”。相应的对策 :一是限制和约束政府权力和职能 ,包括以政企分开为突破口 ,加快现代企业制度建设 ;规范政府干预职能及行为 ;加强对政府调控行为的监督 ;在政府经济职能重构的基础上 ,精简政府机构等。二是提升政府能力特别是宏观调控能力 ,包括财政宏观调控能力、金融宏观调控能力和行政组织调控能力 ;提高政府决策的科学化程度 ;将成本—效益观念和竞争机制引入政府调控的某些领域等 ,从而积极、适度、有效地行使政府对市场运作的宏观调控职能 ,充分发挥政府干预与市场调节二元机制的优势互补作用     

The Quality of Urban Environments in the Brazilian Amazon

In the Brazilian Amazon during the 1980s,urban population growth outstripped rural growth, andby 1991, most of the region's population resided inurban areas. Much of this urban growth involvedestablishment of unplanned housing with inadequateinfrastructure, which resulted in rising pollution. This paper compares indicators of environmentalquality in urban populations of the Amazon in 1980 and1991, and among different kinds of urban populationsin 1991. The results show that environmental qualityin the region deteriorated during the 1980s as theproduction of and exposure to environmental hazardsrose while resources to ward off hazards eroded. Thefindings also show that environmental quality wasparticularly poor in more rapidly growing urbancenters. The urban Amazon may not afford an adequatestandard of living and this may generate out-migrationfrom the region.     

提高妇女素质是提高人口素质的重要保证

母亲的素质对孩子的优生优育有直接的重大影响 ,因此 ,提高妇女素质是全民族刻不容缓的任务     

M-quantile models with application to poverty mapping

Over the last decade there has been growing demand for estimates of population characteristics at small area level. Unfortunately, cost constraints in the design of sample surveys lead to small sample sizes within these areas and as a result direct estimation, using only the survey data, is inappropriate since it yields estimates with unacceptable levels of precision. Small area models are designed to tackle the small sample size problem. The most popular class of models for small area estimation is random effects models that include random area effects to account for between area variations. However, such models also depend on strong distributional assumptions, require a formal specification of the random part of the model and do not easily allow for outlier robust inference. An alternative approach to small area estimation that is based on the use of M-quantile models was recently proposed by Chambers and Tzavidis (Biometrika 93(2):255–268, 2006) and Tzavidis and Chambers (Robust prediction of small area means and distributions. Working paper, 2007). Unlike traditional random effects models, M-quantile models do not depend on strong distributional assumption and automatically provide outlier robust inference. In this paper we illustrate for the first time how M-quantile models can be practically employed for deriving small area estimates of poverty and inequality. The methodology we propose improves the traditional poverty mapping methods in the following ways: (a) it enables the estimation of the distribution function of the study variable within the small area of interest both under an M-quantile and a random effects model, (b) it provides analytical, instead of empirical, estimation of the mean squared error of the M-quantile small area mean estimates and (c) it employs a robust to outliers estimation method. The methodology is applied to data from the 2002 Living Standards Measurement Survey (LSMS) in Albania for estimating (a) district level estimates of the incidence of poverty in Albania, (b) district level inequality measures and (c) the distribution function of household per-capita consumption expenditure in each district. Small area estimates of poverty and inequality show that the poorest Albanian districts are in the mountainous regions (north and north east) with the wealthiest districts, which are also linked with high levels of inequality, in the coastal (south west) and southern part of country. We discuss the practical advantages of our methodology and note the consistency of our results with results from previous studies. We further demonstrate the usefulness of the M-quantile estimation framework through design-based simulations based on two realistic survey data sets containing small area information and show that the M-quantile approach may be preferable when the aim is to estimate the small area distribution function.     

Interplay between Friends' Aggression and Friendship Quality in the Development of Child Aggression during the Early School Years

The aim of this study was to investigate the unique and combined role of friendship quality and friends' aggression in regard to the persistence of young children's physical aggression from kindergarten to grade 2. The sample included 1555 children (808 girls) assessed annually using teacher ratings. Two theoretical perspectives (i.e., the social learning and the social bonding perspectives) served as frameworks to guide the analyses and interpret the results. In line with the social learning perspective, friends' aggression was related to a significant increase in children's physical aggression. However, in line with the social bonding perspective, good friendship quality played both a compensatory and a protective role, by, respectively, reducing children's initial level of physical aggression and by mitigating, albeit marginally, the associations between friends' and children's physical aggression. These results suggest that fostering a positive relationship between friends in the early school years may decrease physical aggression even if the friends are aggressive.     

基于主体功能区划自然保护区生态补偿机制之构建与完善

根据国家主体功能区划,自然保护区被界定为禁止开发区域,必然要对其科学有效地实施生态补偿;自然保护区生态补偿机制应当结合当前主体功能区划的政策导向,进行重新定位与构建。依据公共物品与外部性等理论,为缓解现实矛盾,需积极探索构建多元化融资渠道的保护区生态补偿机制,主要涉及政府与市场两种基本途径或机制范畴,合理安排相应的政策引导与制度创新。制度构建的关键在于加快自然保护区生态补偿的立法调整,无论是政府财政转移支付还是市场经济手段的生态补偿政策,都需要立法确定其方针原则、实施模式及机制。     

Parameter Estimation for a Discretely Observed Integrated Diffusion Process

Abstract.  We consider the estimation of unknown parameters in the drift and diffusion coefficients of a one-dimensional ergodic diffusion X when the observation is a discrete sampling of the integral of X at times i Δ , i  =  1 ,…, n . Assuming that the sampling interval tends to 0 while the total length time interval tends to infinity, we first prove limit theorems for functionals associated with our observations. We apply these results to obtain a contrast function. The associated minimum contrast estimators are shown to be consistent and asymptotically Gaussian with different rates for drift and diffusion coefficient parameters.     

Between stability and higher-order asymptotics

We discuss the effects of model misspecifications on higher-order asymptotic approximations of the distribution of estimators and test statistics. In particular we show that small deviations from the model can wipe out the nominal improvements of the accuracy obtained at the model by second-order approximations of the distribution of classical statistics. Although there is no guarantee that the first-order robustness properties of robust estimators and tests will carry over to second-order in a neighbourhood of the model, the behaviour of robust procedures in terms of second-order accuracy is generally more stable and reliable than that of their classical counterparts. Finally, we discuss some related work on robust adjustments of the profile likelihood and outline the role of computer algebra in this type of research.