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151.
Using data from a racially and ethnically diverse sample of low-income mothers of 2-year-old children participating in the Early Head Start Research and Evaluation Project (N = 883), the authors examined fathers' education and employment, mother-father relationship, and mothers' relationships with kin in the household to explain variation in nonresident father involvement across racial and ethnic groups. Nonresident White fathers were less involved with their children than were African American and Latino fathers. This difference was explained by the status of mother-father relationships. White nonresident fathers were less likely than minority nonresident fathers to maintain romantic relationships with their child's mother. Mothers in the White father group were also more likely to re-partner, which negatively related to biological fathers' involvement. These findings suggest that approaches to strengthen nonresident father involvement in children's lives need to consider how father ethnicity and mother-father relations are associated with differential patterns of father involvement.  相似文献   
152.
Agents which perform inferences on the basis of unreliable information need an ability to revise their beliefs if they discover an inconsistency. Such a belief revision algorithm ideally should be rational, should respect any preference ordering over the agent’s beliefs (removing less preferred beliefs where possible) and should be fast. However, while standard approaches to rational belief revision for classical reasoners allow preferences to be taken into account, they typically have quite high complexity. In this paper, we consider belief revision for agents which reason in a simpler logic than full first-order logic, namely rule-based reasoners. We show that it is possible to define a contraction operation for rule-based reasoners, which we call McAllester contraction, which satisfies all the basic Alchourrón, Gärdenfors and Makinson (AGM) postulates for contraction (apart from the recovery postulate) and at the same time can be computed in polynomial time. We prove a representation theorem for McAllester contraction with respect to the basic AGM postulates (minus recovery), and two additional postulates. We then show that our contraction operation removes a set of beliefs which is least preferred, with respect to a natural interpretation of preference. Finally, we show how McAllester contraction can be used to define a revision operation which is also polynomial time, and prove a representation theorem for the revision operation.  相似文献   
153.
People who prefer larger, later gains over smaller, sooner gains when considering outcomes far in the future often reverse their preference as the alternatives become closer in time. This finding, which is contrary to a normative economic account of intertemporal choice, has been interpreted as support for hyperboloid discounting, but the results can also be explained by steeper discounting of smaller amounts. The present study is the first to demonstrate that analogous preference reversals occur with losses: People who preferred a smaller, sooner loss over a larger, later loss when the outcomes were far in the future reversed their preference when these alternatives were closer in time. Because there was no magnitude effect (i.e., smaller losses were not discounted more steeply than larger losses), the present findings strongly support the proposition that reversals in preference between delayed outcomes occur because of the hyperboloid shape of the discounting function.  相似文献   
154.
ObjectivesBased on ecological systems theory [Bronfenbrenner, U. (2005). Making human beings human: Bioecological perspectives on human development. Thousand Oaks, CA: Sage], the purpose of this study was to examine parents’ involvement in competitive youth sport settings.DesignData were collected through two distinct phases of fieldwork. Phase 1 involved longitudinal data collection with four families. Phase 2 involved observations of youth soccer settings.MethodData were collected from four families via individual interviews and audio-diaries and were supplemented through 120 h of observation. Data were transcribed verbatim and analyzed using grounded theory methodology.ResultsParents’ verbal reactions to their children's sport performance behaviors were placed on a continuum moving from more supportive to more controlling comments. These comments were categorized as praise/encouragement, performance contingent feedback, instruction, striking a balance, negative comments, and derogatory comments. Parents experienced empathy in that they perceived sharing the emotions their children felt in sport, and these emotions appeared to change in relation to dynamic game and contextual circumstances. Parents also thought that they possessed knowledge and expertise of sport, which they perceived enabled them to make comments to their children.ConclusionA series of reciprocal and bi-directional relationships were central to parents’ involvement in competitive youth sport.  相似文献   
155.
In this study we explored the effects of respondent gender and the specific gender combination (i.e., cross- and same-gender dyads) on perceptions of a sexual encounter between a teacher and an adolescent student. Respondents (120 male and 120 female undergraduates) read a brief scenario and answered questions about their perceptions of the encounter. Significant interactions emerged between teacher gender and student gender. For example, the male teacher/male student dyad was viewed as the least normative, and the female teacher/male student dyad was perceived as the most normative. Significant interactions also were found between teacher gender and respondent gender. Results generally were consistent with gender role stereotypes.  相似文献   
156.
Access can either be first-order or second-order. First order access concerns whether contents achieve representation in phenomenal consciousness at all; second-order access concerns whether phenomenally conscious contents are selected for metacognitive, higher order processing by reflective consciousness. When the optional and flexible nature of second-order access is kept in mind, there remain strong reasons to believe that exclusion failure can indeed isolate phenomenally conscious stimuli that are not so accessed. Irvine’s [Irvine, E. (2009). Signal detection theory, the exclusion failure paradigm and weak consciousness—Evidence for the access/phenomenal distinction? Consciousness and Cognition.] partial access argument fails because exclusion failure is indeed due to lack of second-order access, not insufficient phenomenally conscious information. Further, the enable account conforms with both qualitative differences and subjective report, and is simpler than the endow account. Finally, although first-order access may be a distinct and important process, second-order access arguably reflects the core meaning of access generally.  相似文献   
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159.
Cholecystokinin elicits the complete behavioral sequence of satiety in rats.   总被引:10,自引:0,他引:10  
The behavior of intact rats and rats with chronic gastric fistulas was observed and scored during a 60-min test period when they were offered liquid diet after 17 hr of food deprivation. Intact rats and rats with closed fistulas displayed a specific behavioral sequence at the end of each meal: They stopped eating, engaged in grooming and exploration for a short time, and then rested or slept. Thus, a fixed behavioral sequence characterizes satiety in the rat. Although the behavioral sequence of satiety was fixed, the cessation of feeding was not a sufficient condition for the appearance of the rest of the sequence: Quinine adulteration of the liquid diet stopped sham feeding but did not elicit the complete sequence. Intraperitoneal injection of the intestinal hormone cholecystokinin during sham feeding, however, elicited the complete sequence of satiety. The observation that cholecystokinin not only stops feeding but elicits the complete sequence of satiety supports our hypothesis that endogenous cholecystokinin is a satiety signal for the rat.  相似文献   
160.
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