Sampling Strategies for Toxic Air Contaminants

Annual concentrations of toxic air contaminants are of primary concern from the perspective of chronic human exposure assessment and risk analysis. Despite recent advances in air quality monitoring technology, resource and technical constraints often impose limitations on the availability of a sufficient number of ambient concentration measurements for performing environmental risk analysis. Therefore, sample size limitations, representativeness of data, and uncertainties in the estimated annual mean concentration must be examined before performing quantitative risk analysis. In this paper, we discuss several factors that need to be considered in designing field-sampling programs for toxic air contaminants and in verifying compliance with environmental regulations. Specifically, we examine the behavior of SO2, TSP, and CO data as surrogates for toxic air contaminants and as examples of point source, area source, and line source-dominated pollutants, respectively, from the standpoint of sampling design. We demonstrate the use of bootstrap resampling method and normal theory in estimating the annual mean concentration and its 95% confidence bounds from limited sampling data, and illustrate the application of operating characteristic (OC) curves to determine optimum sample size and other sampling strategies. We also outline a statistical procedure, based on a one-sided t-test, that utilizes the sampled concentration data for evaluating whether a sampling site is compliance with relevant ambient guideline concentrations for toxic air contaminants.     

美苏在德国赔偿问题上的矛盾与德国的分裂

德国在二战后被分裂成两个国家,就其外部因素来讲,是由于以美苏为首的大国合作政策在战后逐渐走向对抗并导致冷战的产物,是外部力量施加于德国的结果,而在走向对抗的过程中,美苏在德国赔偿问题上的冲突,是导致德国分裂的一个重要原因。     

对现代大学办学指导思想的理性思考

现代大学办学指导思想是现代大学发展的灵魂,是搞好现代大学各项事业的总开关,是现代大学生存与发展的生 命线。现代大学办学指导思想的特征表现为思想性、指导性、实践性和发展性。     

城市发展的可持续性测评初探

城市发展是否是可持续的已成为人们关注的焦点,如何测度与评价城市发展的可持续性尚无统一的认识。文章设计了一个评价城市可持续发展的框架,借助于常用统计数据,并利用应用统计学方法筛选出一个由17个指标构成的测评指标体系,运用层次分析法确定权重,并以天津市为实证案例,测度并评价其1990—1999年这10年间发展的可持续性。     

面向基础教育课程改革的教师教育职前培养模式探析

在师范教育转型的过程中，师范院校应转变传统的人才培养观念。针对基础教育课程改革，积极进行教师教育职前培养模式创新探索，培养具有综合的学科知识和专业化教育水平的新型教师，适应基础教育课程改革的需要。     

试论清代两湖地区书院的刻书业及其兴盛原因

历代书院刻印的图书,在版本学上称为"书院本"。其版本价值较高,历来倍受文士学者重视。清代两湖地区的书院兴盛且日益官学化,书院刻书业比较发达,留下大量作品。究其原因,主要包括社会、政治、经济、文化和学术五个方面。     

A qualitative comparative analysis of strategies for an ageing society, with special reference to pension and employment policies

The primary purpose of this study is to typify the respondent strategies of the OECD countries based on the interconnected structure of income and employment guarantees. More specifically, this article seeks to typify welfare policies into four types (welfare-to-work, welfare emphasis, labour emphasis, market emphasis) based on the leniency of the pension system and active state intervention in employment security. With the resultant four types, this article then places them as the dependent variable while incorporating per capita GDP, aged dependency ratio, pension maturity level, union density, constitutional structure index and degree of decommodification as causal variables. Through this process, this article aims to derive the decisive variable for each type through qualitative comparative analysis.     

Bayesian analysis of elapsed times in continuous‐time Markov chains

The authors consider Bayesian analysis for continuous‐time Markov chain models based on a conditional reference prior. For such models, inference of the elapsed time between chain observations depends heavily on the rate of decay of the prior as the elapsed time increases. Moreover, improper priors on the elapsed time may lead to improper posterior distributions. In addition, an infinitesimal rate matrix also characterizes this class of models. Experts often have good prior knowledge about the parameters of this matrix. The authors show that the use of a proper prior for the rate matrix parameters together with the conditional reference prior for the elapsed time yields a proper posterior distribution. The authors also demonstrate that, when compared to analyses based on priors previously proposed in the literature, a Bayesian analysis on the elapsed time based on the conditional reference prior possesses better frequentist properties. The type of prior thus represents a better default prior choice for estimation software.     

民族自治地方农村养老问题与对策初探——以黔东南州锦屏县为例

民族自治地方农村养老工作与构建社会主义和谐社会、社会主义新农村建设、“三农”问题等紧密相关，养老工作能否解决好直接影响到农村的社会稳定、社会的和谐发展和“三农”问题的解决。民族自治地方农村经济相对落后、经济发展不平衡、人口分布不均衡、农村老年人口日益增多、农民工大量外出等现实，给传统养老方式带来了历史性的冲击。这要求建立具有时代特色和地方特色的养老方式。本文在进行充分的实地调查、分析黔东南苗族侗族自治州锦屏县农村现行的养老方式现状、养老方式存在问题的基础上，结合当地实际情况和借鉴其他地方的成功养老方式，提出具体可行的对策。     

长三角近海海洋环境管理立法研究

长江三角洲经济区海洋经济发展势头强劲，但同时其近海也饱受海水水质恶化、赤潮灾害频发、海洋生态非健康等环境问题的困扰。长三角近海环境问题的解决需要一种特殊的环境管理方式，即区域海洋环境管理，这是海洋环境管理理论不断发展创新的成果，可以起到解决自然区域与行政区划之间的矛盾、协调多方利益和中观管理的有益补充作用。本文拟探讨通过贯彻区域海洋环境管理理念，创设适用于长三角毗邻海域的、针对海洋环境管理的区域性法律文件，来治理与维护这一海洋区域的环境，从而为其海洋经济发展创造有利条件，提供良好的环境依托，使发展走上可持续的道路。