中国人口迁移与生育率关系研究

本文利用2000年人口普查数据,考察了中国人口迁移与生育率的关系。通过比较农村本地人口、城市本地人口和流动迁移人口三个人口群体在生育率上的差异,并进行多元统计分析,结果表明,流动迁移对生育率有着非常显著影响,城市外来人口的生育率不仅显著低于农村本地人口,而且也低于城市本地人口;远期流迁人口的生育率要低于近期流迁人口的生育率。中国人口迁移与生育率的关系出现了与已有的迁移生育率理论的不一致。1990年代中国的迁移生育率发生了转变。     

低生育率水平下人口发展的经济后果分析

本文分析了低生育率水平下人口发展对未来我国经济发展的积极影响 ,同时指出它是一把双刃剑 ,同样也有不利于经济发展的后果。为了既充分发挥低生育水平的积极作用 ,又逐步消除或缓解其不良后果 ,一方面要适时地调整现行生育政策 ,选择适当的总和生育率水平 ,另一方面要构建相应的政策支持体系予以支撑。     

“Try to make it seem like we're regular kids”: Youth perceptions of restrictiveness in out-of-home care

While there are several measures of living environment restrictiveness, none has used the youth perspective in conceptualizing and operationalizing restrictiveness. The purpose of this qualitative study was to obtain the perspectives of child welfare involved youth who have lived in out-of-home care. Using focus group methodology, 40 youth were asked to define restriction and give examples of how it is operationalized in practice. Youth defined restriction as “rules”. The rules were about what youth can do, where they can go, who they can be with and how and with whom they can communicate. These rules were primarily characterized as inconsistent, arbitrary, non-individualized and developmentally inappropriate, although some characterized them as beneficial in the long term. Rules were mostly attributed to adult need for power and avoidance of legal responsibility for the youths. Typical feelings about the rules were anger, resentment, feeling labeled, isolated and stigmatized. Relationships influenced perceptions: within a positive relationship, youth understood and tolerated the rules that limited independence. The perception of what were normal restrictions for other youth not in out-of-home care was another influencing factor. These findings are examined in light of cognitive and affective development in adolescence. Recommendations for improving the measurement of living environment restrictiveness as well as enhancing child welfare services are proposed.     

2000例健康体检者血尿酸血脂水平的调查

目的了解中大五院健康体检者的血尿酸(UA)、血清甘油三酯(TG)和总胆固醇(TC)水平与性别、年龄的关系。方法对2000例体检者检查资料进行整理分析,按性别、年龄分组,用酶法检测体检者血清尿酸、甘油三酯、总胆固醇水平,进行调查分析。结果 UA、TG和TC水平总趋势均随着年龄增长而逐渐增高(P<0.05),50-岁年龄组各项指标显著高于其他年龄组(P<0.01)。血尿酸男性平均值为381.5±86.3μmol/L,女性为308.3±67.5μmol/L,各年龄组男性均明显高于女性,有非常显著性差异(P<0.01)。TG和TC各年龄组男性均明显高于女性,有非常显著性差异(P<0.01)。结论血尿酸、血脂水平与年龄因素有关。随年龄增长,尿酸血脂水平升高,30岁以上年龄组各项指标均显著高于30岁以下年龄组,提示年龄从30岁开始预防痛风和动脉硬化有重要意义。     

关于中国全要素生产率测度的研究——基于一阶差分对数模型和有效资本存量的再测算

本文对以往我国全要素生产率测度中存在的问题做了较为系统的分析,试图总结一套科学且具有可操作性的测度方法。本文在区分实际资本存量和有效资本存量的基础上,根据我国资本存量估算数据,采用一阶差分对数模型和有关经济计量学方法,估计资本与劳动的产出弹性,避免了可能出现的“伪回归”“序列相关”“多重共线性”和“异方差”等问题,从而保证所测度的产出弹性估计值既符合经济理论分析又能通过经济计量学检验。本文还阐述了全要素生产率与广义技术进步这两个指标 的联系与区别,并通过实证分析揭示了不同时期两项指标产生差异的原因。实证分析结果表明,改革开放以来全要素生产率提高对促进我国经济增长发挥了重要作用。     

怎样的制造企业更愿涉足服务业务?———“服务化困境”问题的生产率匹配探析

本文关注于制造业企业服务化过程中的产业效率因素,设计了差异化产品模型。在需求层面,公司所提供的产品和服务之间具有互补性;而在供应方面,企业在产品生产和服务之间在专业知识分配上存在竞争。理论模型提供了对制造企业服务化与全要素生产率之间的计量评估。本文利用我国上市制造业版块中的企业数据,通过使用具有异质性的Fractional Probit 模型控制内生性并进行实证检验,理论模型推导和经验估计指出,企业全要素生产率与服务化之间存在“U”型关系,针对四个行业部门的检验也证实服务化和企业全要素生产率之间的非线性关系。在不同地区的企业之间,“U”型关系也存在差异。企业所处行业环境、所在区域以及所提供产品和服务的内在特征对于“服务化困境”的表现都存在差异性的影响。     

认真评价本犯的事后行为

"不可罚的事后行为"给人当然不可罚的印象,因而"共罚的事后行为"的概念更为准确;在本犯行为因为具有违法性阻却事由、责任阻却事由、超过追诉时效以及在诉讼法上不能证明时,能够而且必须对事后行为单独进行评价;未满十六周岁的人盗窃财物或捡拾遗忘物,满十六周岁后故意加以毁坏的,构成故意毁坏财物罪;本犯教唆他人作伪证的,可能构成妨害作证罪;杀人后碎尸的,将侮辱尸体罪与故意杀人罪数罪并罚,有助于减少故意杀人罪死刑的不当适用;间歇性精神病人伤害他人,恢复正常后不救助而导致他人死亡的,构成不作为的故意杀人罪.     

Estimation of parameters in heavy-tailed distribution when its second order tail parameter is known

Estimating parameters in heavy-tailed distribution plays a central role in extreme value theory. It is well known that classical estimators based on the first order asymptotics such as the Hill, rank-based and QQ estimators are seriously biased under finer second order regular variation framework. To reduce the bias, many authors proposed the so-called second order reduced bias estimators for both first and second order tail parameters. In this work, estimation of parameters in heavy-tailed distributions are studied under the second order regular variation framework when the second order parameter in the distribution tail is known. This is motivated in large part by a recent work by the authors showing that the second order tail parameter is known for a large class of popular random difference equations (for example, ARCH models). The focus is on least squares estimators that generalize rank-based and QQ estimators. Though other possible estimators are also briefly discussed, the least squares estimators are most simple to use and perform best for finite samples in Monte Carlo simulations.     

Tests for assessment of agreement using probability criteria

For the assessment of agreement using probability criteria, we obtain an exact test, and for sample sizes exceeding 30, we give a bootstrap-t$t$ test that is remarkably accurate. We show that for assessing agreement, the total deviation index approach of Lin [2000. Total deviation index for measuring individual agreement with applications in laboratory performance and bioequivalence. Statist. Med. 19, 255–270] is not consistent and may not preserve its asymptotic nominal level, and that the coverage probability approach of Lin et al. [2002. Statistical methods in assessing agreement: models, issues and tools. J. Amer. Statist. Assoc. 97, 257–270] is overly conservative for moderate sample sizes. We also show that the nearly unbiased test of Wang and Hwang [2001. A nearly unbiased test for individual bioequivalence problems using probability criteria. J. Statist. Plann. Inference 99, 41–58] may be liberal for large sample sizes, and suggest a minor modification that gives numerically equivalent approximation to the exact test for sample sizes 30 or less. We present a simple and accurate sample size formula for planning studies on assessing agreement, and illustrate our methodology with a real data set from the literature.     

张掖市虚拟水投入产出分析

 虚拟水战略是水资源社会化管理的一个重要途径。本文应用地区水资源投入产出模型,剔出外地调入品影响,通过本地完全需水系数,以及完全需水量与直接用水量比较,计算了张掖市产业间虚拟水的净转移以及区域虚拟水的调入调出,进一步构造了产业间虚拟水转移矩阵,清晰量化各产业间虚拟水的转移去向。结果表明,种植业及其他农业是虚拟水最大的净转移和输出部门,利用的水实际向制造业和畜牧业大量转移, 畜牧业又将种植业转移来的水大部分输出外地。通过量化经济部门之间对水资源需求的数量关联效应,从投入产出分析视角为张掖市水需求管理提供新的参考。