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81.
The influence of a genetic risk factor, apolipoprotein E (apoE) epsilon4 variant, was assessed in older adults aged 70 to 94 on 3 occasions over 7 years. The results of latent growth curve analyses are reported for individuals genotyped for apoE at the 2nd measurement occasion (n = 601) and for a subsample of individuals without probable or definite dementia during the 1st or 2nd occasion (n = 434). ApoE-epsilon4 status was a significant predictor of level and change in memory performance and change in speed performance in the full sample, and of initial level and change in memory performance in the nondemented subsample. These results support previous findings that apoE-epsilon4 is associated with accelerated memory deterioration in individuals without clinical dementia.  相似文献   
82.
Women with disabilities have low employment rates and about one-third live in poverty. They represent half of the population using either services of the vocational rehabilitation (VR) system or the welfare system, and many use both. Although both systems have made gains in improving their employment status, neither comprehensively addresses the needs of this population. Welfare policy has encouraged state level innovation and moved large numbers of people into employment in as little as five years. State welfare agencies offer a range of services specifically addressing the needs of families with children. VR agencies have decades of specific experience assisting people with disabilities gain employment. Welfare reform has been the cruise ship moving large numbers of people across an ocean. VR agencies have been the kayak builders designing specialized small craft to move specific people along tributaries. What can they learn from each other? Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
83.
The single-trial passive avoidance task is a useful procedure for examining learning and memory in the young chick. However, it has recently been suggested that discrepant results reported by different laboratories are due to differences in training procedure. The present study investigated a number of parameters surrounding the passive avoidance task, using day-old White Leghorn, Black Australorp cockerels. The results suggested that presentation of a water-dipped bead immediately after the aversive bead significantly altered retention levels. In addition, when the water-dipped bead was presented after the aversive bead, chicks failed to discriminate between beads for a period of 10 min following exposure to the aversant experience. A novel variant of the passive avoidance procedure, involving pretraining with a water-dipped red bead, training with an aversant-coated red bead, and testing with a dry red bead, was evaluated. A measure of avoidance was calculated using all three trials. It is suggested that the use of a single bead, measured both before and after the training experience and using both aversant- and water-trained controls, results in the most concise characterization of memory-related phenomena in the chick which is not contaminated by a carryover effect from the aversive training experience to the nonaversive bead.  相似文献   
84.
Glucocorticoid modulation of emotional memory has repeatedly been shown in aversive learning paradigms, but has received little attention in appetitive tasks. It has also been suggested that it may be selective for contextual cues. In order to investigate if glucocorticoids can modulate memory in discrete-cue conditioning of both appetitive and aversive tasks, two experiments were carried out. Male Lister-Hooded rats received pairings of an auditory cue and either food-reward (experiment 1) or footshock (experiment 2), followed immediately by posttraining injections of the glucocorticoid receptor agonist dexamethasone (0.3, 0.6, and 1.2 mg/kg) or vehicle. Dexamethasone (1.2 mg/kg) led to significantly enhanced learning. These results give support to the notion that glucocorticoids play a role in the modulation of both appetitive and aversive emotional memories and show that their role in learning goes beyond the construction of context representations. The modulation of appetitive and aversive discrete-cue learning may be subserved by a common mechanism.  相似文献   
85.
Little is known about how a prey species' cognitive limitations might shape a predator's prey-capture strategy. A specific hypothesis is investigated: predators take advantage of times when the prey's attention is focussed on its own prey. Portia fimbriata, an araneophagic jumping spider (Salticidae) from Queensland, is shown in a series of 11 experiments to exploit opportunistically a situation in which a web-building spider on which it preys, Zosis genicularis (Uloboridae), is preoccupied with wrapping up its own prey. Experimental evidence supports three conclusions: (1) while relying on optical cues alone, P. fimbriata perceives when Z. genicularis is wrapping up prey; (2) when busy wrapping up prey, the responsiveness of Z. genicularis to cues from potential predators is diminished; and (3) P. fimbriata moves primarily during intervals when Z. genicularis is busy wrapping up prey. P. fimbriata's strategy is effective partly because the wrapping behaviour of Z. genicularis masks the web signals generated by the advancing P. fimbriata's footsteps and also because, while wrapping, Z. genicularis' attention is diverted away from predator-revealing cues. Electronic Publication  相似文献   
86.
Current theoretical thinking about dual processes in recognition relies heavily on the measurement operations embodied within the process dissociation procedure. We critically evaluate the ability of this procedure to support this theoretical enterprise. We show that there are alternative processes that would produce a rough invariance in familiarity (a key prediction of the dual-processing approach) and that the process dissociation procedure does not have the power to differentiate between these alternative possibilities. We also show that attempts to relate parameters estimated by the process dissociation procedure to subjective reports (remember-know judgments) cannot differentiate between alternative dual-processing models and that there are problems with some of the historical evidence and with obtaining converging evidence. Our conclusion is that more specific theories incorporating ideas about representation and process are required.  相似文献   
87.
This paper reviews research which discusses the risk and protective functions that families and other caregivers provide in influencing the development of aggressive behavior in youth. Currently, there is an emphasis on providing violence prevention programs in the school environment, typically with little parental or caregiver involvement. By enhancing the role of families and caregivers in youth violence prevention programs, we assert that an unique opportunity exists to both address specific risk factors for violence while enhancing the protective features of the family. Relatedly, the risk literature on youth violence indicates that the most influential risk factors (i.e., the family, community, and peers) have their principle impact on youth aggression outside the school. We suggest a shift in the focus of violence prevention programming that is more inclusive of families as both a risk and protective agent. In support of this position, relevant theory and reviews of exemplary family-involved programs are offered. Challenges to involving youth caregivers are identified and recommendations for overcoming those challenges suggested. Last, recommendations for future research and public policy in the prevention of youth violence are offered.  相似文献   
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90.
Optimistic bias among potential perpetrators and victims of youth violence   总被引:2,自引:0,他引:2  
This study furthers the current understanding of optimistic bias regarding youth violence among high school students. Results from a survey of 387 urban high school students indicate a wide range of predictors of optimistic bias, including experience, demographics, and attitudes. Linkages to other developmental frameworks (personal fable and self-efficacy) suggest future directions for additional research.  相似文献   
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