Is there an optimum number of night shifts? Relationship between sleep,health and well-being

Abstract

By concentrating on the impact of a specific shift-system feature on the well-being of those concerned, rather than on the impact of the shift system as a whole, one might be able to offer more meaningful suggestions as to what constitutes a better form of shift system. The present study focused on the impact of the number of consecutive night shifts worked on the health and well-being of two groups of nurses (permanent night and rotating shift). All nurses completed a copy of the Standard Shiftwork Index, which is a set of questionnaires designed for comparing the effects of different types of shift system on large groups of workers. It includes measurements of psychological ill-health, physical ill-health, chronic fatigue, social and domestic disruption, attitudes towards shiftwork, sleep quality and sleep habits. Results showed clearly the impact of the number of consecutive nights worked on health and well-being, not directly, but indirectly through the impact on sleep duration and sleep quality. Sleep duration was shown to increase with more consecutive nights worked. This in turn was found to predict sleep quality, which in turn was found to be the stronger direct predictor of psychological and physical ill-health: i.e. better health was associated with longer and better quality sleeps. Explanations in terms of circadian adaptation are discussed.     

Relations Among Religiousness,Spirituality, and Sexual Practices

Although religiousness is commonly associated with limited sexual activity, little is known about spirituality's unique effect. Study aims involved measuring spirituality's unique affect on young adults' sexual practices (frequency of sex, number of sexual partners, and condom use) and determining whether spirituality adds significant increment over well-established predictors. Three hundred fifty-three (61% female) heterosexual young adults aged 17 to 29 completed this cross-sectional, self-report questionnaire study. Hierarchical regression analyses demonstrated spirituality is positively associated with participants' number of sexual partners and frequency of sex without a condom. Spirituality contributed to the prediction of participants' number of partners and condom use above and beyond the variance accounted for by religiousness, alcohol use, and impulsivity. A moderating effect for gender was found. Spirituality appears to have a unique and strong association with the sexual practices of young adults, particularly women, and should be assessed in future studies of young adults' sexual practices.     

ON CONFIDENCE INTERVALS FOR GENERALIZED ADDITIVE MODELS BASED ON PENALIZED REGRESSION SPLINES

Generalized additive models represented using low rank penalized regression splines, estimated by penalized likelihood maximisation and with smoothness selected by generalized cross validation or similar criteria, provide a computationally efficient general framework for practical smooth modelling. Various authors have proposed approximate Bayesian interval estimates for such models, based on extensions of the work of Wahba, G. (1983) [Bayesian confidence intervals for the cross validated smoothing spline. J. R. Statist. Soc. B 45 , 133–150] and Silverman, B.W. (1985) [Some aspects of the spline smoothing approach to nonparametric regression curve fitting. J. R. Statist. Soc. B 47 , 1–52] on smoothing spline models of Gaussian data, but testing of such intervals has been rather limited and there is little supporting theory for the approximations used in the generalized case. This paper aims to improve this situation by providing simulation tests and obtaining asymptotic results supporting the approximations employed for the generalized case. The simulation results suggest that while across‐the‐model performance is good, component‐wise coverage probabilities are not as reliable. Since this is likely to result from the neglect of smoothing parameter variability, a simple and efficient simulation method is proposed to account for smoothing parameter uncertainty: this is demonstrated to substantially improve the performance of component‐wise intervals.     

Social Capital and the Growth of the Nonprofit Sector*

Objectives. This article examines the extent to which nonprofit organizational foundings are determined by various forms of social capital. Our hypothesis is that, controlling for other relevant social, political, and economic factors, communities with higher levels of social capital should experience more extensive growth in their nonprofit sectors. Methods. Using data derived from the Social Capital Community Benchmark Survey and the IRS “charitable organization” Business Master Files, we test our hypothesis using a negative binomial event count regression on nonprofit organization foundings in 284 U.S. counties in the year 2001. Results. We find that two core dimensions of social capital—political engagement and “bridging” social ties—have a significant impact on county‐level nonprofit foundings. Surprisingly, a key element of social capital in the literature, the level of interpersonal trust, does not lead to an increase in foundings of new not‐for‐profit organizations. Conclusions. This study provides further evidence of the strength of political engagement and bridging ties for the vitality of the community. It also shows that the different dimensions of social capital do not manifest a uniform effect on nonprofit sector growth. These results further demonstrate that the growth of a community's not‐for‐profit sector is dependent on a mix of ecological and environmental factors, especially preexisting organizational density, median household income, unemployment, and levels of governmental spending. Overall, social capital can usefully be seen as another key “environmental” factor in explanations of organizational foundings.     

Adolescent Triangulation Into Parental Conflicts: Longitudinal Implications for Appraisals and Adolescent‐Parent Relations

Although triangulation into parental conflict is a risk factor for child and adolescent maladjustment, little is known about how triangulation affects adolescents' functioning or the factors that lead children to be drawn into parental disagreements. This prospective study examined the relations between triangulation, appraisals of conflict, and parent‐child relations in a sample of 171 adolescents, ages 14 to 19 years, at 2 time points. Cross‐lagged path analyses revealed that youths who experienced greater threat in response to conflict reported increases in triangulation over time, and triangulation was associated with increased self‐blame and diminished parent‐adolescent relations. This study highlights links between intrapersonal, dyadic, and triadic processes and suggests a mechanism by which interparental discord spills over into parent‐adolescent relations.     

Traditionalism or Low Self‐Control?: Explaining the Health‐Risk Behaviors of American Indian Youth

Using a sample of American Indian high school students, we test self-control and Native traditionalism as predictors of their health-risk behaviors. Regression analyses found self-control to be a significant influence on all seven health-risk items as well as the health-risk composite. Traditionalism by and large fails to influence these behaviors. However, the traditionalism measure serves a second purpose as a means of controlling for cultural variation while testing the influence of self-control. In doing so, self-control remains a robust predictor. By controlling for cultural variation and examining behaviors that transcend cultural definitions of deviance, we believe these results support the cultural invariance thesis of self-control. Implications for refining traditionalism, testing the cultural invariance of self-control, and considering new directions in understanding the health risks among American Indians are discussed.     

Likelihood estimation for a longitudinal negative binomial regression model with missing outcomes

Joint damage in psoriatic arthritis can be measured by clinical and radiological methods, the former being done more frequently during longitudinal follow-up of patients. Motivated by the need to compare findings based on the different methods with different observation patterns, we consider longitudinal data where the outcome variable is a cumulative total of counts that can be unobserved when other, informative, explanatory variables are recorded. We demonstrate how to calculate the likelihood for such data when it is assumed that the increment in the cumulative total follows a discrete distribution with a location parameter that depends on a linear function of explanatory variables. An approach to the incorporation of informative observation is suggested. We present analyses based on an observational database from a psoriatic arthritis clinic. Although the use of the new statistical methodology has relatively little effect in this example, simulation studies indicate that the method can provide substantial improvements in bias and coverage in some situations where there is an important time varying explanatory variable.     

The "Honest broker" Role and Evaluation Research Affirmed

This article responds to criticisms of the "honest broker" role of evaluation research done in the positivist tradition. Quantified, statistically representative information frequently has greater utility and perceived credibility than activist research. It also better fits the information needs of policymakers. The roles of evaluations in a dynamic, national policymaking environment are explored. "Mixed results" are shown to be the result of variation in recipients and program implementation as well as assessing multiple outcome variables.     

“二语习得”理论及其在双语教学中的应用

双语教学在我国高等院校的开展已有十余年的实践,但教学效果褒贬不一,有效的双语教学模式仍是困扰双语教学质量的一个关键。本文结合克拉申(S.D.Krashen)关于第二语言习得理论的五种假设以及广东白云学院国际合作办学项目BTEC HND的实际经验,提出了一些双语教学中可以应用的教学理念和教学方法并努力形成一个理想双语教学模式的框架。