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41.
Kathrin Koslicki argues that ordinary material objects like tables and motorcycles have formal proper parts that structure the material proper parts. Karen Bennett rejects a key premise in Koslicki's argument according to which the material ingredient out of which a complex material object is made is a proper part of that object. Koslicki defends this premise with a principle motivated by its power to explain three important phenomena of material composition. But these phenomena can be equally well explained by a weaker principle that does not support the questioned premise in Koslicki's argument, Bennett argues. I show that Bennett's weaker principle, together with an appropriate strengthening of a different premise in Koslicki's original argument, still yields a sound argument for the existence of formal parts.  相似文献   
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Resiliency theory provides a conceptual framework for studying why some youth exposed to risk factors do not develop the negative behaviors they predict. The purpose of this study was to test compensatory and protective models of resiliency in a longitudinal sample of urban adolescents (80% African American). The data were from Years 1 (9th grade) and 4 (12th grade). The study examined effects of cumulative risk and promotive factors on adolescent polydrug use including alcohol, tobacco and marijuana. Cumulative measures of risk/promotive factors represented individual characteristics, peer influence, and parental/familial influences. After controlling for demographics, results of multiple regression of polydrug use support the compensatory model of resiliency both cross-sectionally and longitudinally. Promotive factors were also found to have compensatory effects on change in adolescent polydrug use. The protective model of resiliency evidenced cross-sectionally was not supported in longitudinal analysis. The findings support resiliency theory and the use of cumulative risk/promotive measures in resiliency research. Implications focused on utilizing multiple assets and resources in prevention programming are discussed.  相似文献   
43.
Learning abilities are exhibited by many animals, including insects. However, sedentary species are typically believed to have low capacities and requirements for learning. Despite this view, recent studies show that even such inconspicuous organisms as larval antlions, which employ an ambush predation strategy, are capable of learning, although their learning abilities are rather simple, i.e., limited to the association of vibrational cues with the arrival of prey. This study demonstrates, for the first time, that antlion larvae can use vibrational cues for complex modifications of their foraging strategies. Specifically, antlion larvae rapidly learn to differentiate between the vibrational cues associated with prey of different sizes, and they save resources by ignoring smaller prey in favour of larger, more energetically profitable prey. Moreover, antlion larvae can learn to associate vibrational cues with the loss of their prey, and they respond by burying their victims under the sand more often and more rapidly than do individuals with no opportunities to form such associations. These findings provide not only new insights into the cognitive abilities of animals but also support for the optimal foraging strategy concept, suggesting the importance of maximizing fitness output by balancing the costs and benefits of alternative foraging strategies.  相似文献   
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Twelve months after Hurricane Hugo, 1,000 disaster victims and nonvictims were asked about social support they exchanged following the hurricane. Victims of disaster received and provided very high levels of tangible, informationa, and emotional support. Disaster exposure (loss and harm) was a strong predictor of help received and a modest predictor of help provided. However, postdisaster help was not distributed equally and disaster exposure was more strongly related to social support in some groups than in others. Race, education, and age most consistently moderated the impact of disaster exposure on receipt of postdisaster support. Blacks and less educated victims received less help than similarly affected victims who were white or more educated. Relative disadvantage of being old in receiving support was not the case for those elderly disaster victims who experienced threats to their lives or health. Some subgroups of victims were relied upon disproportionately for providing assistance. Implications for social support research are addressed. This research was supported by Grant MH45069 from the Violence and Traumatic Stress Research Branch of the National Institute of Mental Health to Fran H. Norris, principal investigator.  相似文献   
46.
Postural control and breathing are mechanically and neuromuscularly interdependent. Both systems– of spinal stability and respiration– involve the diaphragm, transversus abdominis, intercostal muscles, internal oblique muscles and pelvic floor muscles. The aim of the study was to evaluate the effect of exercises activating deep stabilizer muscles on postural control and quality of breathing movements. Eighteen volunteers (25,7 ± 3,5) were recruited from the general population. All the subjects implemented an exercise program activating deep muscles. Head, pelvic and trunk positions in the sagittal and frontal planes were assessed with the photogrammetric method. Breathing movements were estimated with the respiratory inductive plethysmography. The results indicate that the use of deep muscle training contributed to a significant change in the position of the body in the sagittal plane (p = 0.008) and the increase in the amplitude of breathing (p = 0.001).  相似文献   
47.
The Polish equivalents of Research Ethics Committees are Bioethics Committees (BCs). A questionnaire study has been undertaken to determine their situation. The BC is usually comprised of 13 members. Nine of these are doctors and four are non-doctors. In 2006 BCs assessed an average of 27.3 ± 31.7 (range: 0–131) projects of clinical trials and 71.1 ± 139.8 (range: 0–638) projects of other types of medical research. During one BC meeting an average of 10.3 ± 14.7 (range: 0–71) projects of medical research were assessed (2006). The amendment of Polish laws according with Directive 2001/20/EC caused a percentage increase in BCs which assessed less than 20 projects per year (16% vs. 33% or 42% in 2003 vs. 2005 or 2006 respectively, p < 0,05). The results confirm the usefulness of the current practice of creating BCs by medical universities, medical institutes and regional chambers of physicians and dentists but rationalization of the workload for individual BCs is necessary.
Marek CzarkowskiEmail:
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New systems of notions specific to the geometry of spine spaces, are introduced. In particular parallelism turns out to be a sufficient primitive notion to express the geometry of a spine space, and we show that structures related to projective closure are definitionally equivalent to spine spaces.  相似文献   
50.
Recently, antlion larvae with greater behavioural asymmetry were shown to have improved learning abilities. However, a major evolutionary question that remained unanswered was why this asymmetry does not increase in all individuals during development. Here, we show that a trade-off exists between learning ability of larvae and their hunting efficiency. Larvae with greater asymmetry learn better than those with less, but the latter are better able to sense vibrational signals used to detect prey and can capture prey more quickly. Both traits, learning ability and hunting efficiency, present obvious fitness advantages; the trade-off between them may explain why behavioural asymmetry, which presumably stems from brain lateralization, is relatively rare in natural antlion populations.  相似文献   
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