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961.
962.
In the course of the twentieth century, African American families have been the objects of a great deal of debate and commentary in social science fields, as well as in popular discourse. The article considers the basis for this discussion: the presence of significant numbers of family and household structures among African Americans that differ from traditional Euro-American models. Western nuclear families are typically centered around marriage, while African, and to a significant degree African American, families are structured around children. The recently developed U.S. Census public use samples and measures oriented to the practices of informal child fosterage are used to examine and compare these different bases of family life. Data from the turn of the century provide some historical distance from previous explanations of difference centered on slavery, or explanations that focus on contemporary social issues such as urban problems or the welfare state. Comparisons with studies of the contemporary U.S., Africa, the Caribbean, and historical materials give broader scope to fosterage analysis and to the consideration of cultural family differences.  相似文献   
963.
This article examines three hostage taking incidents which marked the beginning of an era in the war against international terrorism. These cases are unique because all three were carried out by the same group, the Black September Organization (BSO), occurred within a nine month period, and were of the Barricade/Siege type. This study attempts to explain, by focusing on the Bargaining and Negotiations stages, the processes and outcomes of these events. The comparative analysis yields three findings: (a) There is an evolutionary process in these related cases, and all actors learn from their own and others’ mistakes; (b) Information is important but it is not always available, and it does not dictate the outcome; and (c) All cases involved pre‐determined operating guidelines for the perpetrators, permitting very little space for the actors to maneuver.  相似文献   
964.
965.
We consider a contest where one firm has a cost advantage over rivals. Instead of taking the set of rivals as given, the favorite can transfer the source of its advantage wholly or partially to a subset of rival firms. Foreclosure of those firms that do not receive the cost reduction may result. We present conditions under which this transfer will occur and consider the welfare properties of exclusion. The expected payoff of the dominant firm is independent of the size of the cost reduction transferred to rivals. Applications include lobbying, patent races and access to essential infrastructure.  相似文献   
966.
967.
968.
Evidence from family reconstitution studies suggests that variations in infant mortality may reflect differences in parental solicitude. For various proximate reasons that might originate from emotional, material or social interests, parents may be inclined to invest differently in the survival of their offspring. Evolutionary theory holds that the behavior-regulating mechanisms that cause differential parental care operate in a biologically functional manner. They obey the biological imperative of striving to propagate one's own genetic material in the gene pool of the population to the best possible degree, in view of prevailing socioecological constraints. From a Darwinian point of view, differential parental investment can be best understood as a socioecologically contingent tactical measure within an adaptive, i.e., genetic fitness enhancing strategy. Therefore, human reproductive decisions remain poorly understood unless their biological function in the Darwinian fitness competition is taken into consideration.  相似文献   
969.
970.
Despite research on the effects of intimate partner violence (IPV) on children, little is known about its impact on cognitive development. In this study, 87 preschool-aged children and their mothers exposed to IPV within the last two years participated in interviews to ascertain verbal ability, history of violence, and exposure to trauma. When compared to a national sample of 1,700 same-age children not evaluated for exposure to traumatic events, children exposed to IPV scored significantly lower on verbal ability, as assessed with standardized measures. In order to understand variation in verbal ability, multiple regression models were tested. Both prior exposure to traumatic events and the level of mother’s education were significant predictors of verbal ability. However, level of education mediated the relationship between traumatic events and the child’s verbal ability.  相似文献   
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