The differential gender effect of internalized racism on abdominal obesity in KwaZulu-Natal,South Africa

This research examined the effect of a psychosocial variable, internalized racism, on abdominal obesity, as measured by waist circumference. Results show that the effect of internalized racism on waist circumference persists net of other controls among women, but not among men. Also, among women who had high levels of internalized racism and high educational levels, a positive relationship to abdominal obesity is evident despite the tendency of education to be protective of abdominal obesity. This study supports other research findings that internalized racism is related to waist circumference among adult women but not among men in Western Hemisphere blacks. It also supports past research findings of a gendered reaction to psychosocial stress. It also illustrates that this relationship occurs on the continent of Africa, an area where research on this phenomenon is scarce.     

Clarifying Types of Uncertainty: When Are Models Accurate,and Uncertainties Small?

Professor Aven has recently noted the importance of clarifying the meaning of terms such as "scientific uncertainty" for use in risk management and policy decisions, such as when to trigger application of the precautionary principle. This comment examines some fundamental conceptual challenges for efforts to define "accurate" models and "small" input uncertainties by showing that increasing uncertainty in model inputs may reduce uncertainty in model outputs; that even correct models with "small" input uncertainties need not yield accurate or useful predictions for quantities of interest in risk management (such as the duration of an epidemic); and that accurate predictive models need not be accurate causal models.     

Developing a factor model of coal miners’ attributions on risk-taking at work

This paper details a survey of coal miners’ views on the bases for risk-taking. While literature exists on the subject of risk-taking in mines, comparatively few studies have sought to elicit the views of mine personnel themselves. An 83-item questionnaire, grounded upon insights from an earlier qualitative study, was developed and distributed to a sample of mine personnel (N=932). Results were analysed by means of principal components, factor analysis, an iterative refinement of the data set resulting in the development of a three-factor model that was considered to reflect potentially important dispositional influences on risk-taking amongst operational staff in mines. Derived constructs, identified as time pressure, management commitment and confidence in ability to control risk, were found to possess moderate to high levels of internal consistency (α statistic) and high face validity. Findings are discussed with reference to insights from both cognitive risk research and more recent work within the safety culture/climate framework.     

Quantifying Potential Human Health Impacts of Animal Antibiotic Use: Enrofloxacin and Macrolides in Chickens

Use of similar or identical antibiotics in both human and veterinary medicine has come under increasing scrutiny by regulators concerned that bacteria resistant to animal antibiotics will infect people and resist treatment with similar human antibiotics, leading to excess illnesses and deaths. Scientists, regulators, and interest groups in the United States and Europe have urged bans on nontherapeutic and some therapeutic uses of animal antibiotics to protect human health. Many regulators and public health experts have also expressed dissatisfaction with the perceived limitations of quantitative risk assessment and have proposed alternative qualitative and judgmental approaches ranging from "attributable fraction" estimates to risk management recommendations based on the precautionary principle or on expert judgments about the importance of classes of compounds in human medicine. This article presents a more traditional quantitative risk assessment of the likely human health impacts of continuing versus withdrawing use of fluoroquinolones and macrolides in production of broiler chickens in the United States. An analytic framework is developed and applied to available data. It indicates that withdrawing animal antibiotics can cause far more human illness-days than it would prevent: the estimated human BENEFIT:RISK health ratio for human health impacts of continued animal antibiotic use exceeds 1,000:1 in many cases. This conclusion is driven by a hypothesized causal sequence in which withdrawing animal antibiotic use increases illnesses rates in animals, microbial loads in servings from the affected animals, and hence human health risks. This potentially important aspect of human health risk assessment for animal antibiotics has not previously been quantified.     

Land use conflict after the wildlife and countryside act 1981: the role of the farming and wildlife advisory group

As the conflict between agriculture and conservation in Britain continues, the farming and landowning lobby has placed increasing emphasis on the Farming and Wildlife Advisory Group (FWAG). This paper examines the development of FWAG as a mechanism for self-regulation through a voluntary and co-operative approach to conservation within the farming community. FWAG, until recently accorded little attention either by farmers or government, now enjoys considerable patronage, and new-found financial support from the Countryside Commission. As the National Farmers' Union (NFU) and Country Landowners' Association (CLA) seek to contain the tide of criticism of activities in the countryside FWAG, essentially a practical advisory body, has assumed a crucial ideological importance in the presentation of the farmers' traditional case of ‘stewardship’ and ‘good husbandry’. The paper concludes by stressing the dilemma facing the NFU and CLA as they seek to satisfy the wishes of their own members, government and the conservation lobby.     

Manufacturing resource planning: An information systems model

This paper presents Manufacturing Resource Planning, an information system that will enable the developing and monitoring of strategic plans. Incorporation proven material and capacity requirements planning techniques, strategic planners can determine readily the impact of their plans on the manufacturing resources of the company. Decision making is more coordinated because all managers work from a common data base. However, the attainment of this level of planning sophistication is costly not only in capital outlays for computer software and hardware but also in the time to train users. But those firms who have successfully incorporated this integrated approach to strategic planning feel strongly that the end results justify the expenditures.     

Problem-based Learning: Potential and Implementation Issues

This study addresses the issues associated with the application of problem-based learning, examines the key design dimensions of a problem-based learning course and considers the implications of problem-based learning for learners and educators.     

Biological Basis of Chemical Carcinogenesis: Insights from Benzene

Benzene is one of the best studied of the known human carcinogens. It causes leukemia in humans and a variety of solid tumors in rats and mice. Decades of research on benzene metabolism, pharmacokinetics, cytotoxicity, genotoxicity, and carcinogenicity in vivo and in vitro are starting to converge on a small set of overlapping hypotheses about the most probable biological mechanisms of benzene toxicity and carcinogenicity. Although there is still room for surprises, it seems likely that the ultimate answer to the mystery of how benzene exerts its multiple effects will consist of elaborations and extensions of one or more of the current hypotheses. This paper reviews benzene health effects and biology, showing how various aspects of metabolism and cytotoxicity fit together with genotoxic and nongenotoxic effects to help explain how benzene may cause cancer. Its goals are: (i) to introduce the qualitative biological background needed for detailed quantitative dose-response modeling of benzene cancer risks; and (ii) to survey a rapidly evolving area of research that shows promise of producing fundamental insights into the mechanisms of toxicity and carcinogenesis for several chemicals--benzene and perhaps phenols, catechols, and other hydroxylated ring hydrocarbons--in the decade ahead.     

Extending the Stochastic Two-Stage Model of Carcinogenesis to Include Self-Regulation of the Nonmalignant Cell Population

One of the challenges of introducing greater biological realism into stochastic models of cancer induction is to find a way to represent the homeostatic control of the normal cell population over its own size without complicating the analysis too much to obtain useful results. Current two-stage models of carcinogenesis typically ignore homeostatic control. Instead, a deterministic growth path is specified for the population of "normal" cells, while the population of "initiated" cells is assumed to grow randomly according to a birth-death process with random immigrations from the normal population. This paper introduces a simple model of homeostatically controlled cell division for mature tissues, in which the size of the nonmalignant population remains essentially constant over time. Growth of the nonmalignant cell population (normal and initiated cells) is restricted by allowing cells to divide only to fill the "openings" left by cells that die or differentiate, thus maintaining the constant size of the nonmalignant cell population. The fundamental technical insight from this model is that random walks, rather than birth-and-death processes, are the appropriate stochastic processes for describing the kinetics of the initiated cell population. Qualitative and analytic results are presented, drawn from the mathematical theories of random walks and diffusion processes, that describe the probability of spontaneous extinction and the size distribution of surviving initiated populations when the death/differentiation rates of normal and initiated cells are known. The constraint that the nonmalignant population size must remain approximately constant leads to much simpler analytic formulas and approximations, flowing directly from random walk theory, than in previous birth-death models.(ABSTRACT TRUNCATED AT 250 WORDS)