Sex similarities in occupational status attainment: Are the results due to the restriction of the sample to employed women?

Research on sex differences in occupational attainment suggests that working men and working women attain essentially the same mean level of occupational attainment and do so through quite similar processes. A possible explanation for these similarities is that the sample of working women contains an overrepresentation of successful women, since women who can afford not to work will stay out of the labor force unless they find a job commensurate with their education. This we define as a censoring problem. By extending a technique developed by Heckman, we can estimate the structural parameters for all women, regardless of current employment status. This procedure allows us to assess the impact of the censoring problem on women's occupational attainment equations.     

Size and duration of empires growth-decline curves, 3000 to 600 b.c.

Area changes of about 30 best known empires and states are compiled and tabulated. Superimposed and juxtaposed graphs (size versus time) help to visualize the relative size and location in time of these empires. Size-time integral, maximum stable size, adulthood date, and duration are defined operationally and are listed for 20 empires. A criterion is given for distinctness of successive empires. The size-time integral is a direct measure of an empire's impact on history insofar as that impact depends on sheer size and duration. The integral is largest for the Chinese Hsia-Shang, Egyptian New, Old, and Middle, Assyrian New, and Hittite empires. A world-wide territorial concentration index is tabulated. It increases during the period considered from 0.08 to 1.4% of the world dry land area.     

莱麦草染色体组分析及染色体变异的观察

通过对有丝分裂中期及减数分裂终变期染色体数目统计,形态、行为的观察,发现莱麦草染色体呈现广泛的变异：有丝分裂中期株内染色体数目在2n＝11──56内变化,含有本物种染色体数目2n＝28的细胞仅占统计数的27．8％。减数分裂终变期出现36％具非整倍性的花粉母细胞,染色体数除数目变异外还有结构变异如Robertson易位等。本文对该种进行了染色体组分析,确认其为同源四倍体。同时对该物种株内产生混倍性的原因,在物种进化上的意义进行了探讨。     

Seasonal forcing on the dynamics ofClethrionomys rufocanus: Modeling geographic gradients in population dynamics

We interpret gradients in population dynamics of the gray-sided vole from the southwestern part of the island of Hokkaido to its northeastern part within the framework of a phenomenological model involving the relative length of summer and winter. In Hokkaido, as in other northern regions, both spring and fall is considered as short transition periods between the two main seasons — summer (the primary breeding season) and winter (the non-reproductive or secondary breeding season). We show that the geographic transition in dynamics may be understood as the combined consequence of different patterns of density-dependence during summer and winter, and geographically varying season lengths. Differences are shown to exist between summer and winter with respect to strength of density-dependence. Direct density-dependence, in particular, is stronger during winter than during summer. A model is presented to show how relative lengths of seasons can induce both stable and periodically fluctuating population dynamics. The results are compared and contrasted with what is otherwise known about the gradient in rodent dynamics in Fennoscandia.     

《本草纲目》与伊斯兰(回回)医药的关系

《本草纲目》中的不少“本草”是从西方的伊斯兰诸国传入中国的,伊斯兰民族的医学典籍中的例举及其诠释足可证明这个事实。     

南京市自主创新能力的现状分析

运用企业自主创新能力的评价指标体系,对南京市自主创新能力水平进行纵向和横向比较,可以比较好地把握其自主创新能力的现状。通过对南京市近四年自主创新能力指标的纵向比较,不难发现除了自主创新环境之外,南京市的自主创新资源、自主创新活动以及自主创新产出能力均有较大幅度的增长;通过将南京市与三大科技竞争力较强的城市自主创新能力指标进行横向比较,指出了南京市在自主创新能力上存在的突出问题。一是工业增加值率过低,二是研发经费过低。并在此基础上提出一系列对策和建议。对于提高南京自主创新能力水平,无疑具有重大的理论意义和现实意义。     

人口较少民族发展道路探析——以鄂温克民族为例

本文以鄂温克族为例,探析了人口较少民族发展的道路,分析总结了人口较少民族发展的重要经验。     

民国时期青海省人口统计研究

人口是社会发展的前提与基础,对人口数的还原是再现一个地区在某段时期社会状况的关键。在本文中,笔者通过对有限的资料认真详细的考证、周密细致的分析,论证了民国时期青海省人口发展具有较高的增长率——30‰左右;并以此为基础,对民国时期青海省各个年份的人口数作出估算,希冀能对青海地区社会研究提供借鉴参考。     

《国语》的编撰意图及其文学价值

在中国文学史上,《国语》一向不被人重视。其实不论是从史学角度,还是从文学角度,《国语》都是很值得深入研究的。本文通过对《国语》编撰意图的分析,认为其文学史料不是简单的拼凑,而是紧紧围绕礼治、民本、忠恕、正名等思想选择的。此外,《国语》一书结构的安排,也不只是遵循周王室与各诸侯国关系远近、先华夏后蛮夷的原则,而是另有深意,即反映礼乐崩坏的前因后果。《国语》一书因此成为有机的整体,文学和史学价值也进一步提高。     

SCP视角的资源产业组织及其优化的理论分析

SCP理论是现代西方产业组织(IO)理论中占主导地位的理论。文章试图将该理论运用于自然资源产业问题研究中,也就是运用SCP理论的分析框架来研究资源产业组织问题即自然资源产业内部的资源生产经营企业之间的相互关系,这种理论分析旨在促进资源产业组织不断地趋于合理化和优化。