非拓扑孤子模型的相变特征与袋常数的温度依赖性

本文计算了在有限温度和密度下非拓扑孤子模型的有效势;得到了袋常数对温度和化学势的依赖关系;分析了禁闭解除相变的特征.结果表明:该模型的禁闭解除相变为一级;相变特征的分析表明有退禁闭相与禁闭相的两相共存.     

Costs and Rewards of Children: The Effects of Becoming a Parent on Adults' Lives

How do new parents differ from their childless counterparts in social and psychological resources, daily strains, and psychological well‐being? Using a nationally representative panel of 1,933 adults who were childless at the first interview, we compare 6 indicators of adults' lives for those who became parents and those remaining childless several years later, controlling for earlier states. Becoming a parent is both detrimental and rewarding. With the exception of social integration, which is greater for all groups of new parents compared with their childless counterparts, the effects of parental status on adults' lives vary markedly by gender and marital status. Unmarried parents report lower self‐efficacy and higher depression than their childless counterparts. Married mothers' lives are marked by more housework and more marital conflict but less depression than their childless counterparts. Parental status has little influence on the lives of married men.     

Assessing accuracy of a continuous screening test in the presence of verification bias

Summary.  In studies to assess the accuracy of a screening test, often definitive disease assessment is too invasive or expensive to be ascertained on all the study subjects. Although it may be more ethical or cost effective to ascertain the true disease status with a higher rate in study subjects where the screening test or additional information is suggestive of disease, estimates of accuracy can be biased in a study with such a design. This bias is known as verification bias. Verification bias correction methods that accommodate screening tests with binary or ordinal responses have been developed; however, no verification bias correction methods exist for tests with continuous results. We propose and compare imputation and reweighting bias-corrected estimators of true and false positive rates, receiver operating characteristic curves and area under the receiver operating characteristic curve for continuous tests. Distribution theory and simulation studies are used to compare the proposed estimators with respect to bias, relative efficiency and robustness to model misspecification. The bias correction estimators proposed are applied to data from a study of screening tests for neonatal hearing loss.     

贸易开放、贸易增长与贸易平衡--对转型国家贸易发展的实证研究

本文对1992年到2002年中东欧和独联体25个转型国家贸易开放、贸易增长和贸易平衡问题进行实证研究.文章第一部分简单介绍了转型国家从经互会贸易体制到世界多边贸易体制的发展过程,并提出本文的研究目的、对象以及方法.第二部分用贸易开放、增长和平衡的分析指标对转型国家贸易发展情况作一概述,并引入贸易政策指标、宏观经济指标以及入世虚拟变量等解释因素.第三部分运用面板数据扩展模型(extended model)对转型国家贸易发展的不同作用因素进行统计检验并对结果做出相应分析.第四部分集中对两个转型国家集团-中东欧和独联体-贸易的不同发展状况及其决定因素进行统计检验和比较分析.     

一次计数抽样检验的风险分析

利用抽样检验特征曲线 ,分析了一次计数抽样检验中N ,n ,Ac3个参数的改变对生产者风险和消费者风险的影响     

翻译中的若干技巧

听、说、读、写、译能准确反映出一名英语学习者的英语掌握程度 ,而若想译得准确、流利 ,这的确存在一定的难度。着重阐述了翻译(英译汉 )的标准、方法和若干实用的基本技巧 ,这些技巧包括 :转换法 ,增减法 ,正反、反正表达法和分句、合句法等。如掌握了这些技巧 ,定能起到事半功倍的作用     

Population Policy in Early Victorian England

This paper argues that the generally-held belief that there was no population policy in Great Britain during its fertility transition is incorrect. There were, in fact, clear and implicit and explicit policies in place by the early 19th Century which aimed at reducing population growth. These were negative, involving elimination of family allowances (the famous Poor Laws), and also positive, through subsidised emigration and ``transportation' of felons to the colonies. Moreover, a changed ``ideation' on the part of the nation's political, intellectual and spiritual leaders, changed norms about marriage and child-bearing, raising sharply the perceived economic and psychic cost of children. Lacking acceptable means to control pregnancies, many working class women resorted to abortion, infanticide and child abandonment to reduce their family size. The policy's actual impact on overall fertility is uncertain but it did constitute a deliberate attempt by society to affect demographic behaviour and outcomes.     

The State, Institutional Transition and the Creation of New Urban Poverty in China

Since the 1990s, the introduction of a market economy and the process of rapid urbanization have been accompanied by a new urban poverty related to lay‐offs and unemployment as well as by large‐scale rural–urban migration, which is different from the traditional urban poverty of the ‘Three Nos’ (no relatives or dependants, no working capacity and no source of income). This article focuses on new urban poverty in China under market transition and discusses the causes of poverty creation. Instead of considering Chinese new urban poverty only as a result of market mechanisms, it argues that the state as the manipulator of institutions and policies does matter in the creation of new urban poverty, and that the cleavages between the old and new institutions further intensify it. Specifically, the following aspects of the creation of new urban poverty are examined in detail: the adjustment of industrial policy, the reform of state‐owned enterprises, evolution of the household registration system, and the transformation of the welfare state.     

社会保障转制成本的理论与对策分析

在社会保障制度转换过程中,所有国家都会面临制度转换成本的负担问题。中国要顺利实现社会保障制度由现收现付制向部分积累制转变,政府必须承担新旧制度衔接过程中的全部转制成本。中国可借鉴智利“认可债券”发行经验,以解决目前社会保障资金运行中凸显的个人账户空账运行问题。中国也可借鉴美国“确定受益制”和“确定供款制”两种企业年金计划的成功推行经验,扩大企业补充保险支出,缩小国家基本保险支出,最终减轻政府财政负担,推动国家经济稳定增长。     

Race and Population Change: A Longitudinal Look at Cleveland Neighborhoods

This paper investigates the relationship of racial composition to neighborhood population change from 1910 to 1990 in the Cleveland metropolitan area. To better understand the long-term dynamics of urban neighborhood change, we focus our analysis upon the longitudinal relationship of race, socioeconomic status, and life cycle stage to changes in neighborhood population densities. First, we find that the more established neighborhoods of the African-American community have experienced dramatic declines in population since 1950, a pattern that represents a clear change from the earlier part of the twentieth century. Second, population loss is experienced through a variety of mechanisms, including the demolition of dwellings, the increase in housing vacancy, and the decline of household size. Third, much of this population loss should be interpreted within the context of high economic distress, occurring most frequently in older African-American communities. Over time, economic distress appears to be more important than race in and of itself in leading to the loss of neighborhood populations.