Dynamics of buried seed population and seedling cohorts of two dominant weeds in a hill agroecosystem of the humid subtropics of India

Dynamics of the buried seeds and plant population of two dominant weeds, viz.,Emilia sonchifolia (Linn.) DC. andRichardsonia pilosa HBK were studied in the crop fields of Meghalaya, north-east India during radish and maize cropping and intervening fallow periods. The total buried seed population ofR. pilosa was always larger than that ofE. sonchifolia, but the germinable fraction was invariably greater in the latter. A major portion (39–41%) of the viable (germinable+dormant) seed population in both weeds was confined to the surface soil layer (0–5 cm). The viable seed population ofE. sonchifolia peaked during April, while that ofR. pilosa showed two peaks (during August and December). The survival pattern and half-lives of seedling cohorts showed, some differences in the two weed species, but both being summer annuals, their populations behaved in a similar manner by showing higher seedling recruitment (K) and survivorship (p) rates in the summer crop (maize) than in the winter crop (radish). However, the density of plants that could attain adulthood was significantly higher inE. sonchifolia thanR. pilosa which might have resulted in greater seed input of the former to the soil leading to its greater abundance in the crop fields. Supported by the University Grants Commission, New Delhi (Grants No. F. 3-37/87 SR II)     

Religion as a determinant of marital stability

Using data from the 1987–1988 National Survey of Families and Households, this paper studies the role of the religious composition of unions as a determinant of marital stability. With the exceptions of Mormons and individuals with no religious identification, stability is found to be remarkably similar across the various types of homogamous unions. Consistent with the notion that religion is a complementary marital trait, interfaith unions have generally higher rates of dissolution than intrafaith unions. The destabilizing effect of out-marriage varies inversely with the similarity in beliefs and practices of the two religions as well as with the mutual tolerance embodied in their respective doctrines. The results also suggest that religious compatibility between spouses at the time of marriage has a large influence on marital stability, rivaling in magnitude that of age at marriage and, at least for Protestants and Catholics, dominating any adverse effects of differences in religious background.     

The fertility of migrants before and after crossing the border: the ethnic German population from the former Soviet Union as a case study

Empirical data on persons of German ethnic origin migrating to Germany from the former Soviet Union are used to calculate their relative ferility levels before and after arriving in their new host country. Despite small numbers in the survey , a suitable method was used to effecitvely compare fertility before and after crossing the border with an index measure of national fertility rates. A relatively strong fertility decline was observed for German origin migrants ( Aussiedler ) from the former Soviet Union during their first years in Germany.
More interesting, we consider, is how and to what extent the change in living conditions affected reproductive behaviour after arrival in Germany.
Surprisingly, the fertility of this former high-fertility population fell to a level much lower than the already low German fertility. The extraordinarily high fertility levels of certain religious groups within the former Soviet Union fell even more rapidly after arrival in their new home country.
The results of the study may shed light on another development in Germany: that immediately after reunification the total fertility rate in the former GDR fell to the extremely low level of about 0.6 in 1993 and 1994. The experience of the former East German population is therefore similar to that of German-origin migrants from the former Soviet Union.     

Participation in ethnic associations: the case of immigrants in West Germany

This paper gives the results of a 1981-1982 study of Greek, Italian, and Turkish immigrants in West Germany. Ethnic organizations such as those that presently exist in large numbers in West Germany are often viewed as indicating a lack of social integration and participation by immigrants in the host society. Whether these organizations segregate the immigrants and make their assimilation more difficult, as research on minority groups often claims, or whether they serve as mediating institutions to help integrate and assimilate the newcomers, as other theories would lead one to expect, will depend on the basic orientation of the ethnic organization itself toward the host country. Results indicate the distinctive characteristics of the organizations serving each of these 3 different groups, the extent to which persons of each nationality participate in these associations, the reasons they give for their participation, and the ways in which participation in organizations with different organizations affects the social integration and assimilation of the individual immigrants. Efforts to increase and support the political activities of minority groups at the local level will have positive consequences; this would be 1 modest but decisive step toward eliminating the mutual prejudices of minority and majority group members. As long as immigrants have a clear right to remain in their host country, a secure means of existence, and recognition and acceptance as members of an ethnic minority, their heritage and pride should not be seen as an indication of any lack of identification with the dominant society.     

Macroeconomic determinants of migration: the case of Germany, 1964-1988

Macroeconomic determinants of immigration are analysed with pooled cross-country and time series data on net immigration to Germany from European countries during 1964-1988.
Results demonstrate clearly that both high and low frequency determinants have been important. Long run trends are determined by the degree and speed of per capita income convergence between the sending and receiving countries, while year-to-year changes in net immigration flows are dominated by cyclical economic conditions.     

Nonparametric estimation of transition probabilities in a non-Markov illness–death model

In this paper we consider nonparametric estimation of transition probabilities for multi-state models. Specifically, we focus on the illness-death or disability model. The main novelty of the proposed estimators is that they do not rely on the Markov assumption, typically assumed to hold in a multi-state model. We investigate the asymptotic properties of the introduced estimators, such as their consistency and their convergence to a normal law. Simulations demonstrate that the new estimators may outperform Aalen–Johansen estimators (the classical nonparametric tool for estimating the transition probabilities) in non-Markov situation. An illustration through real data analysis is included.     

论马克思最低工资理论的形成与发展

最低工资理论是马克思工资学说的重要组成部分。马克思最低工资理论经历了产生、发展、成熟和完善等几个发展阶段。马克思对最低工资的内容,它与劳动力价值的关系以及与此相联系的工人阶级经济斗争的意义都经历了一个从初步的认识到完整的科学认识的发展过程     

大型工程建设项目组织综合集成模式

针对大型工程项目组织现状,应用系统论和综合集成方法,提出了工程项目组织基本原理图.构建了项目组织的十元组模型和十纬度集成理论,并对维度进行分析和归约.在此基础上,建立了工程项目组织集成的逻辑框架、结构框架、运作机制和运作框架,以及集成的组织中人力资源的配置方案,进而提出了宜组织的概念.最后将其应用于工程项目实践中,验证证实取得较好效果.这一大型工程项目组织综合集成模式同样也适合特大型工程项目的组织构造,具有较强的理论先进性和使用价值.