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861.
This article reports on a preliminary study of the impact of parent-led prevention groups on youthful drug and alcohol use. In addition, the study assessed the extent to which families involved with parent-led prevention programs reported improved family relations and increased parental control of children's social activities--two major mechanisms by which parent-group advocates claim their activities alter youth substance use patterns. Consistent with the claims of parent-group advocates, the study results suggest that the parent groups did have some impact on family relations and on parental control of children's social activities. The evidence for an impact on drug and alcohol use was, however, weak. A somewhat unexpected finding was that parents who become involved in parent-led prevention activities may not be those parents whose children are at highest risk.  相似文献   
862.
A class of distribution-free tests based on U-statistics has been proposed for testing the null hypothesis of independence against positive quadrant dependence. The tests are based on U-statistics and the Kendall's-tau test belongs to this class.  相似文献   
863.
In this continuation of his article, the author defines severity and acuity of illness and discusses approaches to the measurement of the two factors. He provides some background on severity of illness measures that are in current use and prepares for a discussion of the uses of these measures.  相似文献   
864.
865.
The major objective of this article is to report the findings of two studies which compare and contrast the early child-rearing practices of two generations of Punjabi parents (1970s and 1990s) living in England. Additionally, the findings are compared with a small group of white mothers to broaden our understanding of the changing patterns of parenting. The data was collected through in-depth semi-structured interviews from the first generation during the period 1970–73 and from the second generation in 1995. The research perspective adopted is a qualitative one in that variables and procedures for data collection are not rigorously controlled, and the narratives of the mothers are used extensively to illuminate the key areas of early child rearing. The findings show that the second-generation mothers are shedding most of the traditional customs and practices and are moving towards modern British ways.  相似文献   
866.
Despite frequent references in the sociological literature to Durkheim's theory about the division of labor, sociologists have made few attempts to test it. The paucity of attempts and the very debatable outcomes thereof are due largely to Durkheim's use of the traditional discursive mode of theory construction. A discursively stated theory's logical structure is likely to be obscure, and for that reason alone tests of it are difficult and controversial. Rather than perpetuate the exegetical tradition in sociological treatments of the subject, this paper restates Durkheim's theory in accordance with a particular formal mode. That restatement identifies the theory's shortcomings and problems. But the eight premises imply only one testable theorem, and the theorem's predictive accuracy appears minimal unless "population concentration" is substituted for "density" in the first axiom. Nonetheless, the restatement clearly shows how extension of the theory (additional postulates) could further its testability.  相似文献   
867.
868.
Mixtures of truncated exponentials (MTE) potentials are an alternative to discretization and Monte Carlo methods for solving hybrid Bayesian networks. Any probability density function (PDF) can be approximated by an MTE potential, which can always be marginalized in closed form. This allows propagation to be done exactly using the Shenoy-Shafer architecture for computing marginals, with no restrictions on the construction of a join tree. This paper presents MTE potentials that approximate standard PDF’s and applications of these potentials for solving inference problems in hybrid Bayesian networks. These approximations will extend the types of inference problems that can be modelled with Bayesian networks, as demonstrated using three examples.  相似文献   
869.
A wide body of literature documents the effect of social networks and social supports on mental health. Fewer studies, however, have examined the reciprocal effect of mental health on social relationships. This problem is examined using data from a national panel survey of adults aged 20-64. For the sample as a whole, support was found for a social selection process, since psychological distress predicted decreases in primary, but not secondary, social relationships. The extent of primary relationships also were found to be associated with subsequent distress, providing evidence that the relationship between mental health and social environment may be transactional. When examined separately by gender, males but not females were found to be vulnerable to the process of social selection, supporting the hypothesis that the expression of distress is less role-appropriate for men and therefore more likely to invite social sanctions. Social causation effects also were observed only among males.  相似文献   
870.
A hazard model of the probability of medical school drop-out in the UK   总被引:2,自引:0,他引:2  
Summary.  From individual level longitudinal data for two entire cohorts of medical students in UK universities, we use multilevel models to analyse the probability that an individual student will drop out of medical school. We find that academic preparedness—both in terms of previous subjects studied and levels of attainment therein—is the major influence on withdrawal by medical students. Additionally, males and more mature students are more likely to withdraw than females or younger students respectively. We find evidence that the factors influencing the decision to transfer course differ from those affecting the decision to drop out for other reasons.  相似文献   
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