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991.
992.
The paper explores the outcomes of permanent family placement for children of minority ethnic origin, using a sample of 254 placements drawn, in the main, from a cohort of 1165 British children placed between 1980 and 1985. Statistical techniques are used to explore the relationship between 'success' (defined, for the purposes of this paper, as the placement not known to have broken down) and a range of variables, including the characteristics of the child, the birth parents and the adoptive parents, and the type of placement. In most respects, the findings are consistent with those of similar studies. Age at placement is found to have an important effect, with success least likely for children placed in the middle age range. Lack of problem behaviours in the children at the time of placement is also found to be associated with success. Variables which are found to have no effect on the probability of success include ethnic origin of the child, whether it is an adoptive or permanent foster placement, and whether contact with birth parents continued after placement. There was an interesting gender effect in that boys did better in 'transracial' than in 'matched' placements, but the opposite was the case for girls.  相似文献   
993.
We propose a new method of nonparametric estimation which is based on locally constant smoothing with an adaptive choice of weights for every pair of data points. Some theoretical properties of the procedure are investigated. Then we demonstrate the performance of the method on some simulated univariate and bivariate examples and compare it with other nonparametric methods. Finally we discuss applications of this procedure to magnetic resonance and satellite imaging.  相似文献   
994.
The simplified Conjoint Expected Risk (CER) model by Holtgrave and Weber posits that perceived risk is a linear combination of the subjective judgments of the probabilities of harm, benefit, and status quo, and the expected harm and benefit of an activity. It modifies Luce and Weber's original CER model—that uses objective information to evaluate financial gambles—to accommodate activities such as health/technology activities where values of the model variables are subjective. If the simplified model is a valid modification of the original model, its performance should not be sensitive to the use of subjective information. However, because people may evaluate information differently when objective information is provided to them than when they generate information on their own, the performance of the simplified CER model may not be robust to the source of model-variable information. We compared the use of objective and subjective information, and results indicate that the estimates of the simplified CER model parameters and the proportion of variance in risk judgments accounted for by the model are similar under these two conditions. Thus, the simplified CER model is viable with activities for which harm and benefit information is subjective.  相似文献   
995.
In this paper we present a parsimonious model for the analysis of underreported Poisson count data. In contrast to previously developed methods, we are able to derive analytic expressions for the key marginal posterior distributions that are of interest. The usefulness of this model is explored via a re-examination of previously analysed data covering the purchasing of port wine (Ramos, 1999).  相似文献   
996.
Three experiments investigated the role of prosodic structure for infants' recognition of embedded word sequences. Six‐month‐olds were familiarized with 2 versions of the same sequence, 1 corresponding to a well‐formed prosodic unit and the other to a prosodically ill‐formed sequence (although a successive word series). Next, infants heard 2 test passages. One included the well‐formed unit, and the other included the ill‐formed sequence. In Experiment 1, infants listened longer to the passage containing the well‐formed unit, suggesting that such units, even when they are embedded, are better recognized. Experiments 2 and 3 showed that this better recognition does not depend on an acoustic match between the familiarized sequences and their later embeddings. This suggests that the advantage of the well‐formed unit is at least partially due to infants' use of prosody to parse continuous speech.  相似文献   
997.
A German version of the Organizational Citizenship Behavior Questionnaire (GOCBQ) is developed and tested. Study 1 was conducted with 150 students working together in 39 project groups. The results show that the internal consistency and test-retest-reliability of the GOCBQ are good. Moreover, the GOCBQ measures a general altruism orientation which can be interpreted as a stable trait. The GOCBQ does neither correlate substantially with demographical variables nor with extroversion or neuroticism. Instead, substantial correlations are registered with mood and group atmosphere. In study 2 results from study 1 were cross-validated with data from 128 voluntary and professional helpers, in study 3 with data from 43 professionals. Implications for future research and applications in working life are discussed.  相似文献   
998.
For this exploratory study of the educational orientations of graduate social work faculty, the author surveyed faculty in 38 randomly selected graduate social work departments in the United States in Spring 1991. All were sent a revised Hadley Educational Orientation Questionnaire, which measured their agreement with 12 items each on Mentoring Orientation and Master Teaching Orientation scales. The survey also asked about the source of their educational philosophies. Analysis of 346 responses suggests that faculty tend toward a master teaching approach in attempting to impart essential knowledge and to empower students, but they also incorporate elements from the mentoring approach. Faculty indicated that their educational philosophies were derived principally from work experiences, personal experiences, and professional socialization.  相似文献   
999.
It is argued that migration from Mexico to the US and return migration are determined by international wage differentials and preferences for origin. We use a model of job search, savings and migration to show that job turnover is a crucial determinant of the migration process. We estimate this model by Simulated Method of Moments (SMM) and find that migration practically disappears, it goes down from 19 to 0.5%, had Mexico US arrival rates while employed. A lower decrease in migration, to 7%, occurs by an increase in Mexican wage offers. On the other hand, doubling migration costs reduces migration rates from 19 to 5%, while subsidizing return migration in $300 reduces migration rates only to 14%.  相似文献   
1000.
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