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171.
Some studies generate data that can be grouped into clusters in more than one way. Consider for instance a smoking prevention study in which responses on smoking status are collected over several years in a cohort of students from a number of different schools. This yields longitudinal data, also cross‐sectionaliy clustered in schools. The authors present a model for analyzing binary data of this type, combining generalized estimating equations and estimation of random effects to address the longitudinal and cross‐sectional dependence, respectively. The estimation procedure for this model is discussed, as are the results of a simulation study used to investigate the properties of its estimates. An illustration using data from a smoking prevention trial is given.  相似文献   
172.
ABSTRACT

Objectives: To examine how tobacco use and depression/anxiety disorders are related to disturbed sleep in college students. Participants: 85,138 undergraduate respondents (66.3% female, 74.5% white, non-Hispanic, ages 18–25) from the Spring 2011 American College Health Association–National College Health Assessment II database. Methods: Multivariate analyses of tobacco use (none, intermediate, daily) and mental health (diagnosed and/or symptomatic depression or anxiety) were used to predict sleep disturbance. Results: Daily tobacco use was associated with more sleep problems than binge drinking, illegal drug use, obesity, gender, and working >20 hours/week. Students with depression or anxiety reported more sleep disturbances than individuals without either disorder, and tobacco use in this population was associated with the most sleep problems. Conclusions: Tobacco use and depression/anxiety disorders are both independently associated with more sleep problems in college students. Students with depression and/or anxiety are more likely to be daily tobacco users, which likely exacerbates their sleep problems.  相似文献   
173.
All adoptions, including those facilitated by public agencies, should be evaluated for openness. Although there are no national figures related to openness in public welfare, there are indications that it is not considered in all cases. Adoption myths may be one of the reasons that adoption workers do not always assess a family's ability to maintain a more open adoption arrangement. The following study is the initial validation of a multidimensional psychometric instrument developed to measure myths as they relate to open adoption. Based on a sample of 547 university students, the results indicate very good reliability and acceptable factorial and construct validity. The instrument was designed as a training and research tool to inform child welfare personnel and policy makers of the influence of adoption-related myths on child welfare adoption practice.  相似文献   
174.
Estimation of long-run inefficiency levels: a dynamic frontier approach   总被引:2,自引:0,他引:2  
Cornwell, Schmidt, and Sickles (1990) and Kumbhakar (1990), among others, developed stochasticfrontier production models which allow firm specific inefficiency levels to change over time. These studies assumed arbitrary restrictions on the short-run dynamics of efficiency levels which have little theoretical justification. Further, the models are inappropriate for estimation of long-run efficiencies. We consider estimation of an alternative frontier model in which firmspecific technical inefficiency levels are autoregressive. This model is particularly useful to examine a potential dynamic link between technical innovations and production inefficiency levels. We apply our methodology to a panel of US airlines.  相似文献   
175.
Abstract

Objective: The aim of this Canadian study was to assess student behavioral response to disease transmission risk, while identifying high microbial deposition/transmission sites. Participants: A student survey was conducted during October 2009. Methods: The methods included a survey of students to assess use of health services, vaccination compliance, and hygiene along with a microbial analysis of potential transmission sites targeting specific residence buildings on campus. Results: Results indicated that most students maintained that they were worried about H1N1 and reported making changes in hygienic behavior, with the majority not planning to be vaccinated. The microbial analysis indicated contamination of fomites in co-ed residences to be higher than either male or female student residences. Conclusions: A consideration of physical space along with behavioral factors is required in order to properly assess risk pathways in the establishment of an evidence-based infection control plan for universities and their contiguous communities.  相似文献   
176.
177.
A simultaneous test for the location and scale parameters of the Cauchy distribution is considered based on selected order statistics.. It is shown that optimum spacings that maximise the Pitman ARE of the test coincide with that of the optimum spacings for the estimation problem.  相似文献   
178.
Using qualitative interview data gathered from 28 Hmong adolescents, we examined the meaning ascribed to language and style and how language and style behaviors are used to distinguish identity. We found that the participants used language and style to define their own ethnic group membership and cultural identities. Moreover they inferred meaning from these identity behaviors to discern which peer groups are desirable (those who wear American style clothing and are bilingual) and which are of low social status (“fobby” style clothing and monolingual). The cultural identity symbols used by participants reveal heterogeneity among Hmong adolescent peer groups and evolving definitions of what it means to be Hmong in America.  相似文献   
179.
Many systems approaches speak to the importance of respectful mutual curiosity in supervision rather than linear teacher–learner didacticism. This paper provides an overview of collaborative approaches to supervision in family therapy. It then focuses on Bowen family systems and encouraging differentiation in the relationship process between supervisor and supervisee as a useful approach towards equal collaboration. The authors use case examples to illustrate what impedes and fosters mutuality in the supervision process where both supervisor and supervisee learn from each other.  相似文献   
180.
Risk perception theories posit that changes in risk perception prompt subsequent changes in risk behavior. Prospective studies using observations made at three time‐points offer the capacity to test this hypothesis by observing sequential changes in both risk perceptions and behavior. A telephone survey was administered by random‐digit dialing to 255 adult Australian drivers at baseline (T1), 6 weeks (T2), and 14 weeks (T3). During weeks 2–5, a risk‐perception‐based anti‐speeding mass media campaign was conducted. The survey assessed risk perception, operationalized as the proportion of time that driving at 70 km/h (43 mph) was perceived to be dangerous, and self‐reported speeding behavior, defined as the frequency of respondents driving 5 km (3 mph) faster than the legal speed limit in built up areas. Higher T2 risk perception predicted lower T3 self‐reports of speeding after controlling T1 risk perception and T1 and T2 self‐reported speeding. This can be interpreted as changes in risk perceptions between T1 and T2 predicting changes in speeding between T2 and T3. Further analyses showed that increases in risk perception predicted lower subsequent self‐reported speeding changes, but decreases in risk perception were unrelated to those changes. Risk perception changes were unrelated to recall of exposure to the media campaign. These findings support a dynamic view of the relationship between risk perception and self‐reported behavior, and that risk perception theories can be applied to speeding.  相似文献   
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