846 resultados para MALE PARENTAGE
Resumo:
The pineal gland is known to be light sensitive and to be involved in the seasonal reproduction of male golden hamster Mesocricetus auratus. In general, the pineal gland has been demonstrated to be inhibitory to the reproductive system of the male golden hamster. Melatonin is a pineal hormone which can mimic the action of the pineal gland upon the reproductive system. However, the actual site(s) of melatonin action in the hamster has not been demonstrated. In this study a direct effect of melatonin on the release of FSH and LH from superfused hamster pituitary glands was investigated.^ The superfused pituitary glands showed a stable in vitro basal release of FSH and LH for up to 10 hours. The superfused pituitaries demonstrated reproducible responses to repeated pulses of 10('-8) M LHRH, and a dose-dependent response to stimulation with different concentrations of LHRH.^ Melatonin inhibited the basal release of FSH and LH from superfused hamster pituitary glands. This effect of melatonin was specific and not a general indolamine or catecholamine effect.^ The superfused pituitaries had a diurnal differential responsiveness to physiological concentrations of melatonin with respect to FSH and LH release which were related to the light cycle used to maintain the experimental animals. A LD 14:10 photoperiod cycle was used with light on from 5 a.m. till 7 p.m.. With pituitary glands obtained at 8:30 a.m., the basal release of FSH exhibited an initial inhibition, a gradual rebound at approximately two hours after the beginning of melatonin superfusion, and a significant overshoot of FSH release after the cessation of infusion with melatonin (Morning Response). If the pituitary glands were obtained from hamsters which were sacrificed at 3:30 p.m., the release rate of FSH exhibited an inhibition during the entire period of melatonin infusion with a rebound effect appearing only after melatonin infusion was discontinued (Afternoon Response). There was no significant difference in the responsiveness of the pituitary gland to infusion with melatonin at either 8:30 a.m. or 3:30 p.m. with respect to LH release. Also, melatonin could not inhibit the gonadotropins response to continuous superfusion with 10('-9) M LHRH in pituitaries obtained at either 8:30 a.m. or 3:30 p.m., nor inhibit the stimulatory effect of pulsatile 10('-9) M LHRH. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI^
Resumo:
Despite gains made by Title IX in the past 36 years, including increased female participation in high school and collegiate sport, there is evidence that gender equity in sport is not fully achieved. Researchers target the media because they tend to shape social values and disseminate information to the masses (Kane, 1978, in Fink & Kensicki, 2002). As sports become more pervasive, framing theory has become particularly relevant. The purpose of this study is to build on the Hardin et al. (2002) study by examining the relationship among media sports coverage, gender equity in sport and the perceptions young sports fans begin to form about gender and sport based on media consumption. The researcher hypothesized that since women face discrimination in sport starting from the time that they choose to participate, children will perceive male athletes and their sports as more legitimate. Additionally, the media play a major role in shaping the views of audiences, so the way that they represent male and female athletes, including juxtaposing them, may have an impact on children. The researcher conducted a content analysis of 24 Sports Illustrated for Kids issues from 1996 to 1999 and 24 issues from 2006 to 2007. The researcher analyzed the content of photographs (N=3219) and of headlines (N=762) by using the definitions determined by Hardin et al. (2002). We found that there is a disproportionate amount of coverage devoted to male athletes and that the discrepancy between media representation between men and women in sport has grown since the mid-1990s. This study also includes a focus group conducted with three children from a community swimming program in a northeastern town and found that those children were acutely aware of the differences between men and women in sport based on the discussion. The researcher does not attempt to find a causal relationship between these children’s perceptions and the way media represents them, but rather uses the focus group to complement the content analysis. As children become sports consumers in later life, future research exploring the relationship between children’s perceptions and the media’s representations need to be done before causality and the significance of media effects are determined.
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Moritz Peritz
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Moritz Peritz
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Moritz Peritz
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Moritz Peritz
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Moritz Peritz
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Moritz Peritz
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Moritz Peritz
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von Aug. Wünsche
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von Aug. Wünsche
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von August Wünsche
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von Selig Bamberger
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