Comparative Potency Method for Cancer Risk Assessment: Application to Diesel Particulate Emissions1

An estimation of the human lung cancer “unit risk” from diesel engine particulate emissions has been made using a comparative potency approach. This approach involves evaluating the tumorigenic and mutagenic potencies of the particulates from four diesel and one gasoline engine in relation to other combustion and pyrolysis products (coke oven, roofing tar, and cigarette smoke) that cause lung cancer in humans. The unit cancer risk is predicated on the linear nonthreshold extrapolation model and is the individual lifetime excess lung cancer risk from continuous exposure to 1 μg carcinogen per m³ inhaled air. The human lung cancer unit risks obtained from the epidemiologic data for coke oven workers, roofing tar applicators, and cigarette smokers were, respectively, 9.3 × 10^?4, 3.6 × 10^?4, and 2.2 × 10^?6 per μg particulate organics per m³ air. The comparative potencies of these three materials and the diesel and gasoline engine exhaust particulates (as organic extracts) were evaluated by in vivo tumorigenicity bioassays involving skin initiation and skin carcinogenicity in SENCAR mice and by the in vitro bioassays that proved suitable for this analysis: Ames Salmonella microsome bioassay, L5178Y mouse lymphoma cell mutagenesis bioassay, and sister chromatid exchange bioassay in Chinese hamster ovary cells. The relative potencies of the coke oven, roofing tar, and cigarette smoke emissions, as determined by the mouse skin initiation assay, were within a factor of 2 of those determined using the epidemiologic data. The relative potencies, from the in vitro bioassays as compared to the human data, were similar for coke oven and roofing tar, but for the cigarette smoke condensate the in vitro tests predicted a higher relative potency. The mouse skin initiation bioassay was used to determine the unit lung cancer risk for the most potent of the diesel emissions. Based on comparisons with coke oven, roofing tar, and cigarette smoke, the unit cancer risk averaged 4.4 × 10^?4. The unit lung cancer risks for the other, less potent motor-vehicle emissions were determined from their comparative potencies relative to the most potent diesel using three in vitro bioassays. There was a high correlation between the in vitro and in vivo bioassays in their responses to the engine exhaust particulate extracts. The unit lung cancer risk per μg particulates per m³ for the automotive diesel and gasoline exhaust particulates ranged from 0.20 × 10^?4 to 0.60 × 10^?4; that for the heavy-duty diesel engine was 0.02 × 10^?4. These unit risks provide the basis for a future assessment of human lung cancer risks when combined with human population exposure to automotive emissions.     

Understanding domestic violence against women: using evolutionary psychology to extend the feminist functional analysis

Evolutionary psychologists such as Wilson and Daly (1993b) hypothesize that one goal of male-perpetrated domestic violence is control over female sexuality, including the deterrence of infidelity. According to this hypothesis, domestic violence varies with women's reproductive value or expected future reproduction, declining steeply as women age. We tested this hypothesis with a sample of 3,969 cases of male-perpetrated partner-abuse reported to a single police precinct in a large urban area over a 14-year period. Results show that (a) rates of domestic violence decrease as women age, (b) younger men are at greatest risk for perpetrating domestic violence, (c) younger, reproductive age women incur nearly 10 times the risk of domestic violence as do older, post-reproductive age women, and (d) the greater risk of domestic violence incurred by reproductive age women is not attributable solely to mateship to younger, more violent men. Discussion addresses theoretical implications of these findings and suggests a refinement of the feminist hypothesis of domestic violence against women.     

GAPS between MFT supervision assumptions and common practice: suggested best practices

This article summarizes gaps between assumptions that appear in the literature, research, and accepted standards for marital and family therapy (MFT) supervision, and the common practice of supervisors. Issues that stem from these gaps are highlighted and recommendations are made for closing them. In an effort to refine the standard of practice for MFT supervision, best practice recommendations are offered for MFT supervision.     

Binge Drinking Among Undergraduate College Students in the United States: Implications for Other Substance Use

Abstract

The authors examined the relationship between binge drinking and other substance use among US college students, using nationally representative data from the 1995 National College Health Risk Behavior Survey implemented by the Centers for Disease Control and Prevention. Compared with nonbinge drinkers, current binge drinkers were significantly more likely to report “ever” using and current use of cigarettes, marijuana, cocaine, and other illegal drugs. The researchers also found that the more often students binge drank, the more likely they were to have ever used cigarettes, marijuana, cocaine, and other drugs, and the more likely they were to report current use of cigarettes and marijuana. Those who design programs to prevent binge drinking and use of other substances should take into account the reality that many students use more than one substance and that the more frequently students report binge drinking, the more likely they are to be using other substances as well.     

The Influence of Heuristics on Psychological Science: A Case Study of Research on Creativity

Research heuristics—implicit rules used to guide work on a scientific problem—are explored for their role in guiding psychological research. Work on the psychology of creativity is used to illustrate how heuristics have guided research. We examine the influence of three heuristics: the trilogy-of-mind heuristic, the emotions-as-moods heuristic, and the analysis-of-variance heuristic. This analysis of multiple heuristics provides a new way to understand the state of research on creativity. In the discussion, the analysis is extended to other heuristics and to how heuristics may help as well as hinder innovative research.     

Mexican Immigrants,Labour Market Assimilation and the Current Population: The Sensitivity of Results Across Seemingly Equivalent Surveys

In this paper we compare estimates of immigrants’ labour supply assimilation profiles using the Current Population Survey Annual Demographic Files (March ADS) and the Current Population Survey Outgoing Rotation Groups (ORGs). We use a measure that is seemingly consistent across both surveys: usual weekly hours of work in the main job. This measure is not only important as it measures the intensive margin of labour supply, but it is also used to estimate hourly earnings in both surveys. Our results indicate that the two surveys produce dramatically different estimates of the change in average hours of work as immigrants’ years in the United States increase: estimates from the March ADS predict much steeper hour's assimilation profiles than do estimates obtained from the ORGs. These differences persist if we include controls for demographic characteristics, and only disappear once we control for occupation heterogeneity. We argue that these differences stem from two separate factors that differentiate the data. First, the ADS and ORG frame the usual “hours worked” question differently. Also, differences in the timing of the surveys may produce seasonality effects that differentially affect the composition of recent and earlier migrants, thereby changing assimilation profiles.     

Ageism: Prejudice Against Our Feared Future Self

For decades, researchers have discovered much about how humans automatically categorize others in social perception. Some categorizations—race, gender, and age—are so automatic that they are termed "primitive categories." As we categorize, we often develop stereotypes about the categories. Researchers know much about racism and sexism, but comparatively little about prejudicing and stereotyping based on age. The articles in this issue highlight the current empirical and theoretical work by researchers in gerontology, psychology, communication, and related fields on understanding the origins and consequences of stereotyping and prejudicing against older adults. With the aging baby boomer demographic, it is especially timely for researchers to work to understand how society can shed its institutionalized ageism and promote respect for elders.     

RATIONAL MYTH MAKING AND ENVIRONMENT SHAPING: The Transformation of the Zoo

This article examines a period of political conflict and institutional change concerning North American zoos in the 1970s, focusing on the efforts of industry leaders to secure zoos' institutional status in an unsettled environment. The task involved zoos' national trade association in introducing various institutional elements to build its authority before member organizations and external critics alike. I consider the idea of zoo‐directed captive breeding programs for endangered species, which was adopted as a “rational myth” that influenced organizational identity and public perceptions of zoos. The analysis develops institutional sociology's understanding of culture and strategic behavior's roles in institutional change.