Family structure and child outcomes in the USA and Sweden

Previous research shows that living in a non-intact family is associated with educational disadvantages. This paper compares the relationships between childhood family structure, schooling, and earnings in Sweden and the USA. This comparison is interesting because both family structure and public policies differ significantly. We find a negative relationship between living in a non-intact family and child outcomes, and the estimates are remarkably similar in both countries. After using sibling-difference models, the correlation with family structure is no longer significant. These results cast doubt on the causal interpretation of the negative relationship between non-intact family structures and child outcomes.     

知识经济与人口发展

知识经济将是经济发展的主流 ,它要求社会对科技有巨大的投入 ,而这种投入对经济和社会有更大的回馈 ;知识产业将成为经济结构中的主导产业 ;知识经济以知识价值为核心 ;在知识经济时代世界经济将形成全球化的新格局 ,并对传统产业进行技术改造。知识经济时代对人口数量的制约因素将主要是环境的和空间的适度 ;对提高人口素质的要求更为迫切 ;人口的经济结构将发生重要变化 ,知识工人将成为社会的主导力量 ;人口分布与迁移也将出现集中化分散化的新特点。知识经济对人口学研究提出了更高要求 ,人口学研究手段要实现现代化和信息化 ;人口学要开放化     

吉林省城乡居民消费变化的特点及差异研究

随着城乡居民收入的提高 ,吉林省居民的消费水平有了显著变化 ,按可比价格计算的居民消费水平指数总体上呈上升趋势。进入 90年代以来 ,居民的消费构成也相应发生了很大的转变 ,但城乡之间仍然存在较大的差异。实践表明 ,在经济发展水平相对较高的条件下 ,居民消费的心理、水平、构成及其变化 ,对经济增长的影响力度势必呈现出越来越大的趋势     

Speciation, its ecological and biogeographical consequences

I studied the effect of treehole (microhabitat) size distribution in local habitats on geographic difference in aquatic metazoan community structure by comparing differences between two sites on Iriomote Island, and between Iriomote Island (subtropical) and Tsushima Island (temperate), in southwestern Japan. In treeholes at each local site, the amount of litter, the species richness and total biomass of metazoa were positively correlated with treehole capacity. Between the two sites on Iriomote Island (Shirahama and Komi), the amount of litter, biomass and species number per treehole was greater at Komi where the mean and variance of treehole size were greater, while the dependencies of these parameters on treehole capacity were common to both sites. Total species number was larger at Komi (2 predators and 20 saprophages) than at Shirahama (1 predator and 19 saprophages). Most of the dominant taxa colonized larger treeholes with higher probabilities, although one taxa showed the opposite trend. Treeholes on Tsushima were smaller than those on Iriomote. The metazoan fauna in treeholes consisted of 15 saprophages on Tsushima, being less richer than that on Iriomote Island which had 2 predators and 21 saprophages. However, the dependencies of litter amount and biomass on treehole capacity did not differ significantly between the islands, although treeholes on Iriomote harbored a greater number of species per treehole than those on Tsushima. This study indicated that there are general correlates between community structure within individual treeholes (infracommunity structure) and treehole capacity (microhabitat size). Therefore, microhabitat-size distribution is potentially a significant constraint of local community structure, and its variation may contribute to the variation in local and regional species richness.     

早期大生纱厂内部治理结构的发展及其特征研究

1895年,张謇在南通创设了中国近代有开拓意义的民族企业——大生纱厂。在大生纱厂早期,其内部的管理体制经历了从典型的集权性运营机制到建立起以股东大会、董事会、查帐员为基本特征的三权分立的公司内部治理结构的发展过程。但大生纱厂内部治理始终表现出很强的时代特征,即体现为张謇个人在企业内部的集权特性。这种集权性也是中国近代民族企业早期发展过程中的一个基本特点。     

异形词群系统的意义结构研究

根据词语的义位理论,揭示异形词群系统的内外部意义结构规律,指出异形词系统各组内部"同素同构"与非"同素同构"共存的现象,其他各层级系统间以及异形词群系统与非异形词群系统之间几乎都有一个共同的语素,以利异形词的规范、教学和应用。     

策略、规则及权力结构一所中学高三教师名单的公布

本文以改革后的苏北的一所县级重点中学为个案,以围绕高三教师名单公布的升级事件为切入点,从组织的微观视角出发,描述在升级事件中的教师在各种情境下如何利用手头的已有资源来展开行动的策略,并在游戏各方的行动中构建出一个特有的组织权力结构。     

何谓集合

人们通常用康托集合论来判断ZFC系统的合法性,它对集合有两种主要解释：大小限制概念和叠置概念。大小限制概念把一个收集的统一性或客观现实性看作与该收集自身的大小相关,它不能对基公理和幂集公理的存在性提供合法的解释。集合的叠置观点对于集合的形成存在一个时态的限制,它可证明子集公理和幂集公理的合法性,但是它不能为代换公理提供一个解释。对叠置构造强加一个大小限制条件,可以成功地用来解释代换公理,它不能用来说明幂集公理的合法性。结构观点认为一个集合是打开一个可能结构的模式,集合的同一性应该由它们的打开模式的同一性确定,在这种概念下,没有理由把这种可能的结构限制在良基上。     

Semantic Analysis of the Theoretical Foundations of Biology

生物学理论作为科学哲学研究中的一个另类一直受到关注。它与传统科学模式间的差异是造成这种现象的原因之一。解读这种差异的根源,需要对生物学的理论基础以及理论结构给予充分的关注。生物学特有理论结构所表现出的多元语境与语义结构的复杂性,决定了对生物学理论基础的研究应当重视语义分析的方法,尤其是对理论本身进行语义分解并研究其中的语义关联问题,从而解读生物学模式作为一种不同于理化科学的特殊科学解释观的合理性。     

非平稳时间序列外生性结构突变检验设计的一个实例

一、引言由于世界经济结构的剧烈动荡,如金融危机、政策变更等,致使经济时间序列中的结构突变时有发生,经济过程的结构突变会影响协整分析的结果,使协整方法论中许多有代表性的检验失去原有的功效,如单位根检验[单位根可能会发生漂移(特征根的取值不稳定),单位根检验统计量也可