Modeling U‐Shaped Exposure‐Response Relationships for Agents that Demonstrate Toxicity Due to Both Excess and Deficiency

Essential elements such as copper and manganese may demonstrate U‐shaped exposure‐response relationships due to toxic responses occurring as a result of both excess and deficiency. Previous work on a copper toxicity database employed CatReg, a software program for categorical regression developed by the U.S. Environmental Protection Agency, to model copper excess and deficiency exposure‐response relationships separately. This analysis involved the use of a severity scoring system to place diverse toxic responses on a common severity scale, thereby allowing their inclusion in the same CatReg model. In this article, we present methods for simultaneously fitting excess and deficiency data in the form of a single U‐shaped exposure‐response curve, the minimum of which occurs at the exposure level that minimizes the probability of an adverse outcome due to either excess or deficiency (or both). We also present a closed‐form expression for the point at which the exposure‐response curves for excess and deficiency cross, corresponding to the exposure level at which the risk of an adverse outcome due to excess is equal to that for deficiency. The application of these methods is illustrated using the same copper toxicity database noted above. The use of these methods permits the analysis of all available exposure‐response data from multiple studies expressing multiple endpoints due to both excess and deficiency. The exposure level corresponding to the minimum of this U‐shaped curve, and the confidence limits around this exposure level, may be useful in establishing an acceptable range of exposures that minimize the overall risk associated with the agent of interest.     

中国古代慈善事业的发展特点

中国古代慈善事业在漫长的历史发展过程中不但逐渐形成了庞杂而丰富的思想体系,而且其慈善主体也实现了从最初单纯的国家慈善到以国家慈善为主、宗族慈善和宗教慈善为重要补充的多元化发展过程。另外,中国古代慈善事业的发展轨迹还明显具备与整个中国古代社会兴衰相表里的重要特点。     

Teachers' Attitudes toward Reporting Child Sexual Abuse: Problems with Existing Research Leading to New Scale Development

This paper details a systematic literature review identifying problems in extant research relating to teachers' attitudes toward reporting child sexual abuse and offers a model for new attitude scale development and testing. Scale development comprised a five-phase process grounded in contemporary attitude theories, including (a) developing the initial item pool, (b) conducting a panel review, (c) refining the scale via an expert focus group, (d) building content validity through cognitive interviews, and (e) assessing internal consistency via field testing. The resulting 21-item scale displayed construct validity in preliminary testing. The scale may prove useful as a research tool, given the theoretical supposition that attitudes may be changed with time, context, experience, and education. Further investigation with a larger sample is warranted.     

Effects of Parental Monitoring and Peer Deviance on Substance Use and Delinquency

From socialization theory, it was hypothesized that parental support and monitoring as well as peer deviance would influence individual trajectories of alcohol misuse, other substance use, and delinquency. Six waves of data were analyzed using interviews with 506 adolescents in a general population sample. Results from multilevel modeling showed that monitoring significantly predicted adolescents’ initial levels (intercepts) of alcohol misuse and delinquency. Parental monitoring strongly predicted the rates of increase (slope) in all 3 problem behaviors. Peer deviance significantly predicted initial levels of all problem behaviors and the rates of increase in them. This study provides evidence that both effective parenting and avoidance of associations with delinquent peers are important factors in preventing adolescent problem behaviors.     

Bootstrap adjustments for empirical bayes interval estimates of small-area proportions

Empirical Bayes approaches have often been applied to the problem of estimating small-area parameters. As a compromise between synthetic and direct survey estimators, an estimator based on an empirical Bayes procedure is not subject to the large bias that is sometimes associated with a synthetic estimator, nor is it as variable as a direct survey estimator. Although the point estimates perform very well, naïve empirical Bayes confidence intervals tend to be too short to attain the desired coverage probability, since they fail to incorporate the uncertainty which results from having to estimate the prior distribution. Several alternative methodologies for interval estimation which correct for the deficiencies associated with the naïve approach have been suggested. Laird and Louis (1987) proposed three types of bootstrap for correcting naïve empirical Bayes confidence intervals. Calling the methodology of Laird and Louis (1987) an unconditional bias-corrected naïve approach, Carlin and Gelfand (1991) suggested a modification to the Type III parametric bootstrap which corrects for bias in the naïve intervals by conditioning on the data. Here we empirically evaluate the Type II and Type III bootstrap proposed by Laird and Louis, as well as the modification suggested by Carlin and Gelfand (1991), with the objective of examining coverage properties of empirical Bayes confidence intervals for small-area proportions.     

A Latent Growth Curve Analysis of the Structure of Aggression,Drug Use,and Delinquent Behaviors and Their Interrelations Over Time in Urban and Rural Adolescents

Latent growth curve analysis was used to examine the structure and interrelations among aggression, drug use, and delinquent behavior during early adolescence. Five waves of data were collected from 667 students at three urban middle schools serving a predominantly African American population, and from a more ethnically diverse sample of 950 students at four rural middle schools. One set of models focused on changes in individual behaviors; the other on changes in a global problem behavior factor. Models with separate growth trajectories for aggression, drug use, and delinquent behavior provided the best fit for both samples and revealed relations between initial levels of aggression and subsequent changes in the other behaviors. Boys and girls differed in their initial levels of these behaviors, but not their patterns of change. Differences in growth curve trajectories were found across samples. These findings have important implications for assessment and prevention of problem behaviors in adolescents.     

Understanding the Psychodynamics of Chronic Homelessness from a Self Psychological Perspective

Self psychology can help explain multiple meanings and experiences of being chronically homeless. While it is clear that homelessness is primarily caused by structural deficits and not individual characteristics, for people who are chronically homeless, this way of existence may have developed to serve a variety of coping, cohesive, and self-preserving functions as they have learned to survive and adapt to hostile environments. Through the use of self psychologically informed clinical practice, this paper explores the subject’s multiple meanings and experiences as well as the nuanced processes that led her to successfully attain permanent housing. The paper begins by discussing macro etiologies of homelessness, constructs in self psychology and strives to link the two in theory and practice by exploring one person’s life of chronic homelessness. The paper also explores ethical challenges as coercive elements factor into the case.     

Picking up the challenge: developing a methodology to enumerate and assess the needs of the street homeless population

This study represents the first enumeration of the street homeless population in Canada. Past enumeration attempts have been challenged on their significant methodological shortcomings. This enumeration directly addressed the lessons learned from previous attempts, and improvements to the methodology are presented and discussed. In addition, lessons learned and recommendations are discussed for application to future enumerations.     

Testing the efficacy of the theory of planned behavior to explain strength training in older adults

The purpose of this study was to use the constructs of the theory of planned behavior (TPB) to gain a better understanding of the factors influencing older adults' participation in strength training. Two hundred men and women age 55 years and older were purposely sampled from seniors' centers in Ontario Canada. Participants completed a TPB questionnaire and reported their current physical activity participation. It was hypothesized that perceived behavioral control followed by attitude would be the strongest determinants of strength-training intentions and that intention would be the strongest determinant of strength-training behavior. Regression analyses revealed that subjective norm and perceived behavioral control explained 42% of the variance in intention and intention explained 40% of the variance in behavior. Gender and current strength-training participation did not significantly moderate the relationship between the TPB variables. The results suggest that interventions targeting subjective norm and perceived control might be helpful in promoting strength-training behavior among older adults.