Development of a Unit Risk Factor for 1,3-Butadiene Based on an Updated Carcinogenic Toxicity Assessment

The Texas Commission on Environmental Quality (TCEQ) has developed an inhalation unit risk factor (URF) for 1,3-butadiene based on leukemia mortality in an updated epidemiological study on styrene-butadiene rubber production workers conducted by researchers at the University of Alabama at Birmingham. Exposure estimates were updated and an exposure estimate validation study as well as dose-response modeling were conducted by these researchers. This information was not available to the U.S. Environmental Protection Agency when it prepared its health assessment of 1,3-butadiene in 2002. An extensive analysis conducted by TCEQ discusses dose-response modeling, estimating risk for the general population from occupational workers, estimating risk for potentially sensitive subpopulations, effect of occupational exposure estimation error, and use of mortality rates to predict incidence. The URF is 5.0 × 10⁻⁷ per μg/m³ or 1.1 × 10⁻⁶ per ppb and is based on a Cox regression dose-response model using restricted continuous data with age as a covariate, and a linear low-dose extrapolation default approach using the 95% lower confidence limit as the point of departure. Age-dependent adjustment factors were applied to account for possible increased susceptibility for early life exposure. The air concentration at 1 in 100,000 excess leukemia mortality, the no-significant-risk level, is 20 μg/m³ (9.1 ppb), which is slightly lower than the TCEQ chronic reference value of 33 μg/m³ (15 ppb) protective of ovarian atrophy. These values will be used to evaluate ambient air monitoring data so the general public is protected against adverse health effects from chronic exposure to 1,3-butadiene.     

An assessment of the quality of developmental day center playgrounds for exceptional children

This study assessed the playgrounds of developmental day care centers and compared them with playgrounds of regular certified day care centers. Twenty playgrounds, randomly selected from the listing of developmental day centers, were compared with a matched sample of 20 playgrounds from certified day care centers in one state. A revision of Frost's Playground Rating System (1978b) was employed to rate the two groups of playgrounds on content, safety, and function. Data were analyzed using an analysis of variance technique. The quality of developmental day center playgrounds for exceptional children was inferior to that of regular day care center playgrounds in terms of playground content. No significant differences were noted on safety or function.     

A Weighted Composite Dose – Response Model For Human Salmonellosis

This article describes the development of a weighted composite dose – response model for human salmonellosis. Data from previously reported human challenge studies were categorized into two different groups representing low and moderately virulent/pathogenic Salmonella strains based on a disease end point. Because epidemiological data indicate that some Salmonella strains are particularly pathogenic, and in the absence of human feeding study data for such strains, Shigella dysenteriae was used as a proxy for highly virulent strains. Three single-hit dose – response models were applied to the human feeding study data and evaluated for best fit using maximum likelihood estimation: (1) the exponential (E-1pop), (2) the two-subpopulation exponential (E-2pop), and (3) the Beta-Poisson (BP). Based on the goodness-of-fit test, the E-1pop and BP were the best-fit models for low and moderately virulent/pathogenic Salmonella strains, and the E-2pop and BP models were better for highly virulent/pathogenic strains. Epistemic analysis was conducted by determining the degree of confidence associated with the selected models, which was found to be 50%/50% (E-1pop/BP) for low and moderately pathogenic Salmonella strains, and 9.8%/90.2% (E-2pop/BP) for highly virulent strains. The degree of confidence for each component model and variations in the proportion of strains within each virulence/pathogenicity category were incorporated into the overall composite model. This study describes the influence of variation in strain virulence and host susceptibility on the shape of the population dose – response relationship.     

Violence against immigrants in a context of crisis: A critical migration feminist of color analysis

Abstract

The anti-immigration measures and xenophobic sentiments that have spread since the eruption of the financial crisis in 2008 have been significantly detrimental for immigrant survivors of intimate partner violence in the U.S. given that employment opportunities have declined, exploitative work conditions have worsened, immigration controls have increased, and nonprofit service provision have been under stress. Based on interviews with service providers across the nation, participant observation of networks of advocates of immigrant survivors, and an analysis of debates around the reauthorization of the Violence Against Women Act, I present how these dire circumstances have been disadvantageous for immigrants and the movement to end violence against women. In theoretical terms, my research contributes to the body of literature of critical migration studies by linking such perspective with a feminist of color analysis of gender violence and pointing to the persistent strength of interrelated systems and practices of oppression and marginalization of Latin American immigrants and Latino/as in the U.S.     

Resilience in the Face of Disasters: Bridging Micro- and Macro-Perspectives

This paper discusses the use of risk and resilience theory to understand how individuals and communities respond to natural disasters that present ongoing developmental challenges to personal and collective well-being. In the past two to three decades, mental health workers have developed numerous disaster relief strategies; while economists have become expert at estimating risk. These develops are explored.     

The Beginnings of Tool Use by Infants and Toddlers

Children (aged 9, 14, 19, and 24 months) were encouraged to use tools to achieve a demonstrated goal. Each tool was most efficiently applied when held by the handle with the thumb toward the head of the tool in a radial grip. The tools were presented at midline and oriented to the left and right on alternating trials, so the children who managed to grasp a tool in both orientations with the radial grip demonstrated planning of actions in advance. The tools included a spoon, hairbrush, toy hammer, and magnet; the goals were to feed one's self, feed another, brush one's hair, brush another's hair, hit pegs, and retrieve metal objects. Children were found to use more radial grips with the self‐directed tools (i.e., hairbrush‐to‐self and spoon‐to‐self), indicating that they could plan their actions better when directed toward the self than toward an external goal.     

Consumer-Phase Salmonella enterica serovar Enteritidis Risk Assessment for Egg-Containing Food Products

We describe a one-dimensional probabilistic model of the role of domestic food handling behaviors on salmonellosis risk associated with the consumption of eggs and egg-containing foods. Six categories of egg-containing foods were defined based on the amount of egg contained in the food, whether eggs are pooled, and the degree of cooking practiced by consumers. We used bootstrap simulation to quantify uncertainty in risk estimates due to sampling error, and sensitivity analysis to identify key sources of variability and uncertainty in the model. Because of typical model characteristics such as nonlinearity, interaction between inputs, thresholds, and saturation points, Sobol's method, a novel sensitivity analysis approach, was used to identify key sources of variability. Based on the mean probability of illness, examples of foods from the food categories ranked from most to least risk of illness were: (1) home-made salad dressings/ice cream; (2) fried eggs/boiled eggs; (3) omelettes; and (4) baked foods/breads. For food categories that may include uncooked eggs (e.g., home-made salad dressings/ice cream), consumer handling conditions such as storage time and temperature after food preparation were the key sources of variability. In contrast, for food categories associated with undercooked eggs (e.g., fried/soft-boiled eggs), the initial level of Salmonella contamination and the log10 reduction due to cooking were the key sources of variability. Important sources of uncertainty varied with both the risk percentile and the food category under consideration. This work adds to previous risk assessments focused on egg production and storage practices, and provides a science-based approach to inform consumer risk communications regarding safe egg handling practices.     

Presidential Address on ALTRUISM AND SOCIOLOGY

This article concerns the study of altruism. Highlights of the research history of altruism in sociobiology, psychological social-psychology, and sociology are reviewed. Examples from the author's work on kidney and bone-marrow donation are interwoven with this history. The sociological mechanisms producing altruism, particularly normative obligation, are emphasized along with the psychological mechanisms (e.g., empathy). The need for better integration across subareas in sociology is discussed. In addition, it is concluded that some scientific work significantly trivializes altruism.     

Adolescent crisis and suicidal behavior: Dynamics and treatment

Suicide among adolescents is increasing. Three interacting factors—the crisis of adolescent development, family dysfunctioning, and social factors—create vulnerability to feelings of rejection and worthlessness among suicidal adolescents. Long-term family problems that are not openly acknowledged but for which the adolescent feels responsible are particularly relevant. The authors recommend a multiple approach to assessment and treatment in which crisis intervention is employed initially; and individual treatment for the adolescent and family therapy are utilized concurrently on a long-term basis.