“How Exposed Is Exposed Enough?” Lay Inferences About Chemical Exposure

The concept of exposure is central to chemical risk assessment and plays an important role in communicating to the public about the potential health risks of chemicals. Research on chemical risk perception has found some indication that the model lay people use to judge chemical exposure differs from that of toxicologists, thereby leading to different conclusions about chemical safety. This paper presents the results of a series of studies directed toward developing a model for understanding how lay people interpret the concept of chemical exposure. The results indicate that people's beliefs about chemical exposure (and its risks) are based on two broad categories of inferences. One category of inferences relates to the nature in which contact with a chemical has taken place, including the amount of a chemical involved and its potential health consequences. A second category of inferences about chemical exposure relates to the pragmatics of language interpretation, leading to beliefs about the motives and purposes behind chemical risk communication. Risk communicators are encouraged to consider how alternative models of exposure and language interpretation can lead to conflicting conclusions on the part of the public about chemical safety.     

Job stress, job strain, and psychological withdrawal among Dutch university staff: towards a dualprocess model for the effects of occupational stress

This study examined the antecedents of job strain (emotional exhaustion, health complaints) and withdrawal behaviour (e.g. lowered organizational commitment) among a cross-sectional sample of 131 academic staff members of the law department of a large Dutch university. Conservation of resources theory (Hobfoll, 1989) provided the theoretical background for this study. Strains and withdrawal behaviours were expected to be most prominent among those who reported having few resources and/or who reported high job demands. Structural equation modelling revealed that this was indeed the case. As predicted, differential patterns of effects emerged for job demands and job resources. Analysis of the effects of four job-specific stressors revealed that especially the structural aspects of a staff member's teaching task (e.g. the number of students in their classes) contributed strongly to perceived job demands. Theoretical and practical implications of the study are discussed.     

Career Development and Public Policy

The rationale for policy interest in career development services and the way in which this rationale is being strengthened by the current transformations in work and career are discussed. The potential roles of public policy in relation to career development services are explored, along with ways in which such services can influence the policy‐making process. A range of policy issues related to making career development services available to all throughout life are identified. Stronger structures and processes are needed to bring together career development practitioners with policy makers and other stakeholder interests in order to address tasks of common concern.     

Some properties of tests for parameters that can be arbitrarily close to being unidentified

Confidence intervals for parameters that can be arbitrarily close to being unidentified are unbounded with positive probability [e.g. Dufour, J.-M., 1997. Some impossibility theorems in econometrics with applications to instrumental variables and dynamic models. Econometrica 65, 1365–1388; Pfanzagl, J. 1998. The nonexistence of confidence sets for discontinuous functionals. Journal of Statistical Planning and Inference 75, 9–20], and the asymptotic risks of their estimators are unbounded [Pötscher, B.M., 2002. Lower risk bounds and properties of confidence sets for ill-posed estimation problems with applications to spectral density and persistence estimation, unit roots, and estimation of long memory parameters. Econometrica 70, 1035–1065]. We extend these “impossibility results” and show that all tests of size α concerning parameters that can be arbitrarily close to being unidentified have power that can be as small as α for any sample size even if the null and the alternative hypotheses are not adjacent. The results are proved for a very general framework that contains commonly used models.     

Formative research methods to understand patient and provider responses to heart attack symptoms

Formative research is often required for program planning, and for reducing uncertainty about generalizability of program effects. This article describes and justifies methods of formative research conducted for the REACT study (Rapid Early Action for Coronary Treatment), a multi-center collaborative randomized community trial aimed at reducing patient delay in seeking care for acute myocardial infarction (AMI). Formative research cast light on patient and community members’ decision-making process in seeking help for AMI, as well as barriers and facilitators of this process. Investigators at all five REACT Field Centers participated in the formative research. The process consisted of: (1) developing a common theoretical framework for the study intervention; (2) conducting a literature review and qualitative research to identify and address gaps in knowledge; and (3) developing a common protocol for the REACT study that accommodated the diversity of the target communities in terms of services, resources, history, and ethnicity. Analysis employed triangulation, defined as an explicit search for heterogeneous data sources to reduce uncertainty about forces at work and opportunities for intervention across settings and populations. Because the collection and interpretation of data went in stages, staff of several REACT Field Centers had independent input to the overall synthesis, then shared and revised the results. Advantages and limitations of this approach are discussed.     

Black-White Differentials in Adult Homicide Mortality in the United States

Objective . This article examines individual level black-white differences in adult homicide mortality. Homicide is a major social problem and a central cause of preventable death in the United States. A homicide not only claims one life prematurely but can also devastate a family, friends, and a neighboring community. Methods . We link eight consecutive years of the National Health Interview Survey (1987–94) to the Multiple Cause of Death file through the National Death Index (1987–97), and use Cox proportional hazard models to examine the role of social factors in black-white homicide mortality in the United States. Results . We find that individual level sociodemographic characteristics—age, sex, marital status, education, employment status, and geographic factors—explain almost 35 percent of the racial differences in homicide mortality. Conclusions . These results demonstrate the contributions that National Center for Health Statistics data can make to criminological literature and reveal the mechanisms through which blacks experience higher homicide mortality than whites. Such illumination may lead to a reduction in the fourth leading preventable cause of death in the United States.     

STOCHASTIC KINETIC MODELS: DYNAMIC INDEPENDENCE, MODULARITY AND GRAPHS

The dynamic properties and independence structure of stochastic kinetic models (SKMs) are analyzed. An SKM is a highly multivariate jump process used to model chemical reaction networks, particularly those in biochemical and cellular systems. We identify SKM subprocesses with the corresponding counting processes and propose a directed, cyclic graph (the kinetic independence graph or KIG) that encodes the local independence structure of their conditional intensities. Given a partition [A, D, B] of the vertices, the graphical separation A ⊥ B|D in the undirected KIG has an intuitive chemical interpretation and implies that A is locally independent of B given A ∪ D. It is proved that this separation also results in global independence of the internal histories of A and B conditional on a history of the jumps in D which, under conditions we derive, corresponds to the internal history of D. The results enable mathematical definition of a modularization of an SKM using its implied dynamics. Graphical decomposition methods are developed for the identification and efficient computation of nested modularizations. Application to an SKM of the red blood cell advances understanding of this biochemical system.     

Blessed assurance: Religion, anxiety, and tranquility among US adults

A growing body of research investigates the possible relationships between religion and mental health. After developing a series of arguments linking various aspects of religion with anxiety and tranquility, we test relevant hypotheses using data from the 1996 General Social Survey. Results show that frequency of religious attendance and the belief in an afterlife are inversely associated with feelings of anxiety and positively associated with feelings of tranquility. However, frequency of prayer has no direct association with either outcome. Strong beliefs in the pervasiveness of sin are positively linked with anxiety but unrelated to tranquility. Finally, belief in an afterlife and frequency of prayer buffer the adverse effects of poor health and financial decline on anxiety. Implications of these findings are discussed along with study limitations and promising directions for future research.     

Children's Expression of Emotional Meaning in Music Through Expressive Body Movement

Recent research has demonstrated that preschool children can decode emotional meaning in expressive body movement; however, to date, no research has considered preschool children's ability to encode emotional meaning in this media. The current study investigated 4- (N = 23) and 5- (N = 24) year-old children's ability to encode the emotional meaning of an accompanying music segment by moving a teddy bear using previously modeled expressive movements to indicate one of four target emotions (happiness, sadness, anger, or fear). Adult judges visually categorized the silent videotaped expressive movement performances by children of both ages with greater than chance level accuracy. In addition, accuracy in categorizing the emotion being expressed varied as a function of age of child and emotion. A subsequent cue analysis revealed that children as young as 4 years old were systematically varying their expressive movements with respect to force, rotation, shifts in movement pattern, tempo, and upward movement in the process of emotional communication. The theoretical significance of such encoding ability is discussed with respect to children's nonverbal skills and the communication of emotion.     

Application of the characterization theory to the mixture model

This paper indicates the potential application of the characterization theory to the mixture model. It discusses a particular example of a mixture model and concludes that successful application of this theory can be made in order to choose the appropriate mixture model and the mixing parameter.