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571.
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This study examined the age-specific pattern of effects of welfare policies on child achievement. Drawing from 7 random-assignment welfare and antipoverty evaluations that provided more than 30,000 observations of children's achievement, this study found that times of developmental transition are the only periods sensitive to the changes in families brought about by these policies. More specifically, small positive effects of welfare and antipoverty policies were found for children making the transition into middle childhood, and small negative effects of these same policies were found for children making the transition out of middle childhood and into early adolescence. Effects were robust across various program groupings and could not be attributed to family characteristics that differ for children of different ages. This research informs the understanding of how changes in employment and income for low-income parents affect development across childhood.  相似文献   
573.
In this study the question of whether conflicts over minor issues and over major issues were equally strongly related to satisfaction in romantic relationships was examined. Sixty-four women and 29 men completed the Hendrick (1988) Relationship Assessment Scale for their current main romantic relationship and a 12-item conflict scale (Cramer, 2000b) for minor and major issues. All the relationships were heterosexual. Satisfaction was significantly and equally negatively correlated with conflict over minor and major issues, suggesting that whether an issue is of major or minor importance does not affect satisfaction or dissatisfaction in a romantic relationship. Thus, assessing conflict over major issues may be unnecessary in predicting relationship satisfaction. Conflict over minor and major issues was significantly and positively correlated even when satisfaction was controlled, indicating consistency in conflict resolution.  相似文献   
574.
While professional musicians are generally considered to possess better control of finger movements than nonmusicians, relatively few reports have experimentally addressed the nature of this discrepancy in fine motor skills. For example, it is unknown whether musicians perform with greater skill than control subjects in all aspects of different types of fine motor activities. More specifically, it is not known whether musicians perform better than control subjects on a fine motor task that is similar, but not identical, to the playing of their primary instrument. The purpose of this study was to examine the accuracy of finger placement and accuracy of timing in professional musicians and nonmusicians using a simple, rhythmical, bilateral fingering pattern and the technology that allowed separate assessment of these two parameters. Professional musicians (other than pianists) and nonmusicians were given identical, detailed and explicit instructions but not allowed physically to practice the finger pattern. After verbally repeating the correct pattern for the investigator, subjects performed the task on an electric keyboard with both hands simultaneously. Each subject's performance was then converted to a numerical score. While musicians clearly demonstrated better accuracy in timing, no significant difference was found between the groups in their finger placement scores. These findings were not correlated with subjects' age, sex, limb dominance, or primary instrument (for the professional musicians). This study indicates that professional musicians perform better in timing accuracy but not spatial accuracy while executing a simple, novel, bimanual motor sequence.  相似文献   
575.
This paper studies several concepts about subgroups of automorphisms of linearly ordered relational structures. In particular, it focuses on conditions that are equivalent to the translations (automorphisms with no fixed points plus the identity) forming a homogeneous, Archimedean ordered group under the asymptotic order. For the automorphisms of an ordered relational structure, these properties are equivalent to the structure having a numerical representation whose scale type lies between, but does not exclude, the ratio and interval types (Alper, 1987; Luce, 1987; Narens, 1981a, 1981b). One result of this paper (Theorem 5) is that for the automorphisms of an ordered relational structure the following necessary conditions for such a representation are also sufficient: the asymptotic order induced on the automorphisms is connected, the structure is homogeneous, the translations are Archimedean, and the dilations (i.e., automorphisms with fixed points) are Archimedean relative to all automorphisms. The last property is equivalent to there being at most one proper, nontrivial convex subgroup. Contrary to hope, these results do not seem to lead to a simpler proof than Alper's for the Dedekind complete case. The paper concludes with an examination of the structure of parallel automorphisms. Copyright 2001 Academic Press.  相似文献   
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Several bilinear and nonbilinear utility theories are evaluated using individual data from 144 informants. The nonbilinear models are best for 67% of the informants. The nonrational property of duplex decomposition linking joint receipts and mixed gambles of gains and losses is more adequate than the rational link of general segregation for 73% of the informants. The correlations are very high and linear, even in the worst fitting case. The weighting functions are mostly inverse-S-shaped and for 84% of the informants are fit best by the class of functions proposed by D. Prelec. These fits were generally excellent, with a minimum correlation of.81, a maximum of.99, and an average of.97.  相似文献   
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The inability of assessment center (AC) researchers to find admissible solutions for confirmatory factor analytic (CFA) models that include dimensions has led some to conclude that ACs do not measure dimensions at all. This study investigated whether increasing the indicator–factor ratio facilitates the achievement of convergent and admissible CFA solutions in 2 independent ACs. Results revealed that, when models specify multiple behavioral checklist items as manifest indicators of each latent dimension, all of the AC CFA models tested were identified and returned proper solutions. When armed with the ability to undertake a full set of model comparisons using model fit rather than solution convergence and admissibility as comparative criteria, we found clear evidence for modest dimension effects. These results suggest that the frequent failure to find dimensions in models of the internal structure of ACs is a methodological artifact and that one approach to increase the likelihood for reaching a proper solution is to increase the number of manifest indicators for each dimension factor. In addition, across exercise dimension ratings and the overall assessment rating were both strongly correlated with dimension and exercise factors, indicating that regardless of how an AC is scored, exercise variance will continue to play a key role in the scoring of ACs.  相似文献   
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