民工城乡两栖型就业与城市化

本文从民工的城乡两栖型就业这个角度出发 ,重点分析了对现阶段城市化进程中民工城乡两栖型就业的特点 ,并对民工的城市化归宿问题作了一些探讨     

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     

21世纪我国老年人口规模与老年人力资源开发

21世纪上半叶将是老年人口数量及老龄化突进的时期。老年人力资源是人力资源构成的重要组成部分 ,建立市场机制 ,把老年人愿为现代化建设作贡献的主观愿望和能力 ,与社会发展对老年人力资源的客观需要 ,合理、有效地结合 ,促进人口经济协调发展     

Theory Trimming

This paper attempts to show that the “Theory Trimming” technique makes little contribution to theory in sociology. A brief history of the technique is given, and several key assertions of its proponents are abstracted. These assertions are shown to be highly questionable. The general alternative to Theory Trimming is shown, and the relationship between Theory Trimming and more general orientations to research is discussed.     

On the mode of administering a questionnaire and responses to open-ended items

Concurrently administered personal and telephone surveys are compared to measure differences between the modes for identical questions. Speed of questioning is found to be greater in telephone interviews than personal interviews. The faster pace of telephone interviews is linked to shorter answers to open-ended items on the telephone. The tendency to reduce such responses is disproportionately exhibited by younger, affluent respondents who tend to provide detailed responses in personal interviews.     

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.