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811.
The authors examined factors influencing the return rates for attempting to collect active parental consent forms from 21,123 students in the 7th through 10th grades in 41 middle and high schools. Overall return rates from middle schools were higher than from high schools. Schools that offered high levels of staff support for collecting consent forms had higher return rates. Procedures where the consent form was attached to a school form that parents had to complete and return to the school yielded the highest return rate. Implications for how researchers can obtain a high parent consent form return rate are discussed.  相似文献   
812.
This study examined the association between physical domestic violence (PDV) and reported child maltreatment in a cohort of children at risk for maltreatment. Participants were 219 6- to 7-year-old children and their caregivers. PDV was measured by combining caregivers' self-reports and children's reports, while child maltreatment was based on state Division of Social Services Central Registry records. Among 219 child-caregiver pairs studied, 42 (19.2%) had at least one maltreatment report in the 2 years following the interviews. PDV consistently predicted child maltreatment, with adjusted odds ratios ranging from 2.96 to 3.46. In addition, we investigated interactions between PDV and other predictors of child maltreatment. Among Aid to Families with Dependent Children (AFDC) participants, PDV was highly associated with child maltreatment. However, this pattern was not observed among subjects who did not have AFDC. There is an increased incidence of child maltreatment reports in families experiencing PDV. AFDC participation intensified the probability of child maltreatment in the presence of PDV. Findings also suggest that in households experiencing PDV, social supports may protect children from maltreatment.  相似文献   
813.
Few attempts have been made to incorporate evolutionary and cross-cultural perspectives on gambling. This paper begins with the assumption that gambling represents a risky endeavor undertaken for the purpose of winning stakes. This assumption leads to the derivation from evolutionary theory of two hypotheses concerning the socio-demographic characteristics of gamblers: (1) gambling should be over-represented among males, and (2) among young adults. To test these hypotheses, data are drawn from three sources. A cross-cultural sample of 60 societies reveals that males are more often identified as gamblers than females, and these results do not appear to reflect reporting biases. The data are insufficient to enable conclusions about age patterns associated with gambling within this cross-cultural sample. Nationally representative studies of problem and pathological gamblers drawn from seven nation states show that such gamblers tend to be over-represented by young males, as predicted. Lastly, available demographic data on casino gambling hint at sex differences in the games played and the stakes wagered, but require further research for robust conclusions to be drawn.  相似文献   
814.
This paper describes and evaluates “As luck would have it,” an awareness program completed by retailers in Quebec Province. This program, which is presented as a two-hour awareness promotion workshop, aimed to inform retailers about excessive gambling. More specifically, it provided answers to the following questions: (1) What is chance and randomness? (2) Is there a link between misunderstanding the concept of chance and excessive gambling? (3) How does one recognise the symptoms of this disorder? (4) How should retailers intervene if they decide to do so? Results showed that retailers developed a better understanding of problem gambling, could recognise its main symptoms, felt more capable of coping with excessive gamblers, and of choosing the most appropriate moment to do so. In the follow-up phase, retailers who had attended the workshop reported that they approached a problem gambler significantly more often than the retailers who had not attended the workshop, and had discussed how to help problem gamblers significantly more often. The practical implications of these results are briefly discussed.  相似文献   
815.
816.
Circumstantial evidence places the p66 isoform of the adapter protein Shc in a position to mediate the accelerated aging phenotype displayed by mice expressing shortened forms of the tumor suppressor protein p53. We present a model in which p66(shc) may be responsible for integrating signals from the p53 pathway with signals from the insulin-like growth factor-1/Daf pathway in mammals. A full understanding of how interactions between p53 and p66(shc) affect longevity will require the production of animals with mutations in the genes encoding both proteins.  相似文献   
817.
DNA damage response mechanisms help ensure the fidelity of chromosomal transmission, and the failure of such mechanisms might lead to premature aging and cancer. A new report has established that casein kinase 2 (CK2), a protein that functions in diverse cellular processes, controls the activity of the DNA repair protein XRCC1. These results indicate that CK2 is a key participant in the cellular response to DNA damage.  相似文献   
818.
Genetic variability and diversity are the result of a mutation-selection balance that acts permanently within and between species. The presence of deleterious mutations is a necessary consequence of this process and thus “the price paid by a species for its capacity for further evolution” (Haldane 1937, Am Nat 71:337–349). Recent estimations of mutation rate in the human lineage has revived the debate as to whether the high number of deleterious mutations poses a severe problem for the future of mankind. Theoretical considerations allow a scenario in which the survival of the human race is maintained by truncation selection of deleterious mutations that removes as many mutations as appear anew in every generation. In this case our genetic burden is carried by those individuals that suffer a genetic death resulting from random distribution of deleterious alleles. Nevertheless, one has to ask whether the mutation rate may set absolute limits on the complexity of a species.  相似文献   
819.
When estimating the distributions of two random variables, X and Y, investigators often have prior information that Y tends to be bigger than X. To formalize this prior belief, one could potentially assume stochastic ordering between X and Y, which implies Pr(X < or = z) > or = Pr(Y < or = z) for all z in the domain of X and Y. Stochastic ordering is quite restrictive, though, and this article focuses instead on Bayesian estimation of the distribution functions of X and Y under the weaker stochastic precedence constraint, Pr(X < or = Y) > or = 0.5. We consider the case where both X and Y are categorical variables with common support and develop a Gibbs sampling algorithm for posterior computation. The method is then generalized to the case where X and Y are survival times. The proposed approach is illustrated using data on survival after tumor removal for patients with malignant melanoma.  相似文献   
820.
The gamma process is a natural model for degradation processes in which deterioration is supposed to take place gradually over time in a sequence of tiny increments. When units or individuals are observed over time it is often apparent that they degrade at different rates, even though no differences in treatment or environment are present. Thus, in applying gamma-process models to such data, it is necessary to allow for such unexplained differences. In the present paper this is accomplished by constructing a tractable gamma-process model incorporating a random effect. The model is fitted to some data on crack growth and corresponding goodness-of-fit tests are carried out. Prediction calculations for failure times defined in terms of degradation level passages are developed and illustrated.  相似文献   
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