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.     

A Framework for Time Varying Parameter Regression Modeling

A framework for time varying parameter regression models is developed and employed in modeling and forecasting price expectations, using the Livingston data. Alternative model formulations, which include various choices for both the stochastic processes generating the varying parameters and the sets of explanatory variables, are examined and compared by using this framework. These models, some of which have appeared elsewhere and some of which are new, are estimated and used to assess the expectations formation process.     

The relationship between open innovation,entrepreneurship, and introduction of new business models in Korean and Indonesian information technology enterprises

This case study sought to identify the relationships that can exist between open innovation, entrepreneurship, and the introduction of new business models at the enterprise level. Eleven Korean enterprises and five Indonesian enterprises were chosen, to obtain minimum research generality. While the number of enterprises is not great, it provides enough samples to determine the concrete relationships among these factors. The article starts by pointing out the general relationship between entrepreneurship, open innovation, and the introduction of a new business model. It examines two different contexts: the difference between the Seoul and Daegu regional innovation systems, and the difference between the Indonesian and Korean national innovation systems.     

Walking a tightrope: reflections on police gatekeeping roles in suicide research in Ghana

Engaging non-conventional gatekeepers such as the police presents both promises and perils. Although studies have relied on police data for researching suicide and other sensitive topics in Africa, there is a paucity of literature that explores or reflects on police gatekeeping and its research implications. This paper presents authors’ reflections on police gatekeeping in a qualitative suicide study in Accra, Ghana. The main observation is that the process was double-edged. On the one hand, it led to field delays and costs, (mis)apprehensions and positionality problems, and trust building challenges. On the other hand, it vouched for research(er) credibility, provided therapeutic openings, and facilitated the viability of research with the suicide bereaved. Sensitivity to research context, sensitising the police, and reinforcing ‘therapeutic-research discourse’ with participants, are recommended means for aligning participants’ goals to research goals and for achieving therapeutic disclosures.     

Older Drivers Retiring From the Road: An Application of the Selection,Optimization, and Compensation Model

Purpose: This study uses the selection, optimization, and compensation (SOC) model to compare older adults who have given up driving, those who still drive, and those who drive less to identify differences in the three groups. Design and Methods: This cross-sectional study of 281 older adults is part of the Naturally Occurring Retirement Community Demonstration Project. Study participants completed interviews that included questions on demographics, health and functioning, mental health, social support, and current levels of engagement in activities including current driving status. Results: Data suggest that driving retirement is a process and that a substantial number of people are in the transitional stage, where they are less functional than those who still drive and more similar to those who have retired from the road. Implications: Given the similarity of those who drive less to those who have given up driving, front-line professionals and policy makers must work together to ease the transition to driving retirement for those without adequate ability to effectively compensate for their inability to continue to drive safely.     

Analysis of the image repair discourse in the Michael Phelps controversy

The following study reviews the image repair strategies used by Olympic swimmer Michael Phelps, his sponsors and the organizations that govern him as an amateur swimmer after a picture of Phelps allegedly smoking from a marijuana pipe appeared in a British tabloid. Additionally, the study reviews media coverage of the controversy to determine whether Phelps was successful in repairing his image. The study concludes that Phelps’ image repair campaign was a success. Implications for public relations practitioners and suggestions for future research also are discussed.