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931.
Despite growing concerns about foster placement instability, little information is available regarding the longitudinal patterns of placement histories among foster children. The purpose of the present study was to develop a charting system using child welfare records to facilitate a better understanding of longitudinal patterns of placement history for 117 foster children. The resulting Placement History Chart included all placements that occurred during the observed time period and accounted for various dimensions: number, length, type, and sequence of placements; timing of transitions; and total time in out-of-home care. The Placement History Chart is an effective tool for placing foster care experiences within a broader developmental context. As such, the Placement History Chart can be a valuable research tool for understanding various dimensions and variations of placement transitions among foster children by capturing sequences and cumulative risks over time. Furthermore, this chart can facilitate the development of intervention programs that are developmentally sensitive and effectively address particularly vulnerable subpopulations of foster children. 相似文献
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935.
In a series of major papers culminating in A Theory of Justice, John Rawls constructs an alternative to utilitarianism by developing a social contract theory of moral and political philosophy. Unfortunately, Rawls formulates the two basic principles upon which the theory rests in such a way as to restrict (unduly) the contract theory's applicability (see Section I). In this paper we present a more general discussion of the theory of justice that avoids the problems of Rawls' formulation and yet retains the important idea of justice as fairness and the contractarian approach (Section II). Later it is argued that this more general theory constitutes a bridge between the pure utilitarian theories and the social contract doctrines (Sections V and VI). The theory's advantages are demonstrated by applying it to a problem discussed by Rawls, intergenerational equity, and comparing the two solutions (Section III). Further comparisons are made and inferences drawn in the concluding three sections.Without implicating them, we would like to thank James M. Buchanan and David Lyons for comments on an earlier draft of this paper.
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936.
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Differences between plant varieties are based on phenotypic observations, which are both space and time consuming. Moreover, the phenotypic data result from the combined effects of genotype and environment. On the contrary, molecular data are easier to obtain and give a direct access to the genotype. In order to save experimental trials and to concentrate efforts on the relevant comparisons between varieties, the relationship between phenotypic and genetic distances is studied. It appears that the classical genetic distances based on molecular data are not appropriate for predicting phenotypic distances. In the linear model framework, we define a new pseudo genetic distance, which is a prediction of the phenotypic one. The distribution of this distance given the pseudo genetic distance is established. Statistical properties of the predicted distance are derived when the parameters of the model are either given or estimated. We finally apply these results to distinguishing between 144 maize lines. This case study is very satisfactory because the use of anonymous molecular markers (RFLP) leads to saving 29% of the trials with an acceptable error risk. These results need to be confirmed on other varieties and species and would certainly be improved by using genes coding for phenotypic traits. 相似文献
938.
霍夫的评论表明,那些叙述高海拔缺氧影响人类生育力和生殖能力的文献中弥漫着方法论和概念的迷雾.我们去年的文章主题也谈到了这一点(见<美国人类学家>85:28-49,1983).我们的论文尽力阐述了喜马拉雅山脉的高海拔地区,藏语族群中普遍存在的不同生育力水平,是与某些文献的报道一致的. 相似文献
939.
J. C. W. Rayner O. Thas B. De Boeck 《Australian & New Zealand Journal of Statistics》2008,50(3):235-240
The Emerson (1968, Biometrics 24 , 695–701) recurrence relation has many important applications in statistics. However, the original derivation applied only to discrete distributions. In the following, a simple derivation is given that generalizes the Emerson recurrence relation to any distribution for which the necessary expectations exist. A modern application is outlined. 相似文献
940.
Susan J. Spieker Nancy C. Larson Steven M. Lewis Rachelle D. White Lewayne Gilchrist 《Child and Adolescent Social Work Journal》1997,14(5):335-364
The cognitive and behavioral status at age six years of 185 children of adolescent mothers (60.5% boys) were assessed using the mother (CBCL) and teacher (TRF) report forms of the Child Behavior Checklist and the Bracken Basic Concepts Scale. There was evidence for impairment in all areas of functioning. More than half of the sample exceeded the borderline clinical cutoff (T = 60) on either the CBCL or TRF Total Problem score, and nearly half the sample had Bracken scores that were more than 1 SD below the normative mean. Only 26.9% of the children were in the normal range on all three measures. These results are discussed in terms of implications for social work practice with children and adolescent mother families. 相似文献