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901.
Mutations in the muscle protein titin have been linked to dilated cardiomyopathy, a condition in which the heart chambers are enlarged and blood is ineffectively pumped, in humans and in animal models. This protein, which is a component of sarcomeres, provides essential scaffolding for other muscle proteins and acts as a spring to confer passive elasticity on the cardiomyocyte. Several titin isoforms exist, and they display varying size and degrees of elasticity. We review two interesting reports that show how variations in titin isoforms might be implicated in cardiac failure. 相似文献
902.
903.
Workplaces are ideal contexts for mentoring relationships between adults and older youth. To teach the competencies required in contemporary workplaces (many of which are equally useful in other settings), mentors need to use sophisticated teaching behaviors, which the authors characterize as reflective questioning and problem solving. 相似文献
904.
Choice of Parametric Accelerated Life and Proportional Hazards Models for Survival Data: Asymptotic Results 总被引:1,自引:0,他引:1
We discuss the impact of misspecifying fully parametric proportional hazards and accelerated life models. For the uncensored case, misspecified accelerated life models give asymptotically unbiased estimates of covariate effect, but the shape and scale parameters depend on the misspecification. The covariate, shape and scale parameters differ in the censored case. Parametric proportional hazards models do not have a sound justification for general use: estimates from misspecified models can be very biased, and misleading results for the shape of the hazard function can arise. Misspecified survival functions are more biased at the extremes than the centre. Asymptotic and first order results are compared. If a model is misspecified, the size of Wald tests will be underestimated. Use of the sandwich estimator of standard error gives tests of the correct size, but misspecification leads to a loss of power. Accelerated life models are more robust to misspecification because of their log-linear form. In preliminary data analysis, practitioners should investigate proportional hazards and accelerated life models; software is readily available for several such models. 相似文献
905.
A central sociological problem is the extent to which genetics and the environment influence human behavior. Studies of twins are a core method in attempts to disentangle and to determine the comparative strength of genetic and environmental influences on psychosocial outcomes. A critical assumption of twin studies is that both monozygotic "identical" twins and dizygotic "fraternal" twins share common social environments. Therefore, any greater similarity of monozygotic than dizygotic twins is attributed to genetic influences. This paper tests the equal environment assumption by examining the extent to which greater concordance of adolescent monozygotic compared to dizygotic twins results from social, as well as genetic, influences. Bivariate comparisons indicate that monozygotic twins show greater similarity than dizygotic twins in socially-based characteristics including physical attractiveness, time spent in each other's company, the overlap in friendship networks, and friends' use of alcohol. Multivariate analyses indicate that measures of the social environment sometimes reduce or eliminate apparent genetic effects. In comparison with genetic indicators, social variables are usually stronger predictors of depression and alcohol use and abuse. These findings suggest that past twin studies could overstate the strength of genetic influences because some similarities in behavior among monozygotic compared to dizygotic twins stem from social influences. 相似文献
906.
Corrigan P Markowitz FE Watson A Rowan D Kubiak MA 《Journal of health and social behavior》2003,44(2):162-179
In this study, we build on previous work by developing and estimating a model of the relationships between causal attributions (e.g., controllability, responsibility), familiarity with mental illness, dangerousness, emotional responses (e.g., pity, anger, fear), and helping and rejecting responses. Using survey data containing responses to hypothetical vignettes, we examine these relationships in a sample of 518 community college students. Consistent with attribution theory, causal attributions affect beliefs about persons' responsibility for causing their condition, beliefs which in turn lead to affective reactions, resulting in rejecting responses such as avoidance, coercion, segregation, and withholding help. However, consistent with a danger appraisal hypothesis, the effects of perceptions of dangerousness on helping and rejecting responses are unmediated by responsibility beliefs. Much of the dangerousness effects operate by increasing fear, a particularly strong predictor of support for coercive treatment. The results from this study also suggest that familiarity with mental illness reduces discriminatory responses. 相似文献
907.
Ellickson PL Bird CE Orlando M Klein DJ McCaffrey DF 《Journal of health and social behavior》2003,44(4):525-535
This paper examines the links between individual adolescent smoking behavior and actual and perceived smoking behavior in the individual's school cohort. We hypothesized that students enrolled in schools with higher smoking prevalence among students in their grade are more likely to smoke subsequently. We also expected perceived school-level prevalence of smoking to have a greater impact than actual prevalence because the former is a more direct measure of perceived norms. Adjusting for demographics, actual school-level prevalence at baseline (grade 7) was strongly associated with smoking frequency one year later. However, the association disappeared after adjusting for individual smoking frequency at baseline. School-level prevalence did not moderate the association between individual's baseline and subsequent smoking frequency. Perceived prevalence of smoking among grade 8 students and two measures tapping the behavior of smaller peer groups--cigarette offers and exposure to friends and other peers who smoke--were associated with increased risk of smoking. 相似文献
908.
909.
This article presents a consensus-building initiative to develop a statewide research agenda that responds to the needs of Illinois's child welfare community. Researchers conducted this process through a university-community partnership to engage those interested in child welfare services. The process and findings resulted in a living document that will guide child welfare research throughout the state. Findings of the inquiry suggest that the development of best practice models may be one of the most important contributions research can make to practice. 相似文献
910.
Despite its controversy, carefully conceptualized and delivered couples treatment appears to be at least as effective as traditional treatment for domestic violence, and preliminary data suggests that it does not place women at greater risk for injury. However, the body of research on which these conclusions rest is sparse. Only six experimental studies have been done, each using different eligibility criteria, outcome measures, and treatment approaches. Thus, further study of this modality is warranted. Marriage and family therapists have an important part to play in continuing to develop and test innovative ways of helping couples end violence and improve their relationships--an endeavor that promises to improve the quality of the partners' lives as well as those of their children. 相似文献