Significance of the Dermal Route of Exposure to Risk Assessment

The skin is a route of exposure that needs to be considered when conducting a risk assessment. It is necessary to identify the potential for dermal penetration by a chemical as well as to determine the overall importance of the dermal route of exposure as compared with inhalation or oral routes of exposure. The physical state of the chemical, vapor or liquid, the concentration, neat or dilute, and the vehicle, lipid or aqueous, is also important. Dermal risk is related to the product of the amounts of penetration and toxicity. Toxicity involves local effects on the skin itself and the potential for systemic effects. Dermal penetration is described in large part by the permeability constant. When permeability constants are not known, partition coefficients can be used to estimate a chemical's potential to permeate the skin. With these concepts in mind, a tiered approach is proposed for dermal risk assessment. A key first step is the determination of a skin-to-air or skin-to-medium partition coefficient to estimate a potential for dermal absorption. Building a physiologically-based pharmacokinetic (PBPK) model is another step in the tiered approach and is useful prior to classical in vivo toxicity tests. A PBPK model can be used to determine a permeability constant for a chemical as well as to show the distribution of the chemical systemically. A detailed understanding of species differences in the structure and function of the skin and how they relate to differences in penetration rates is necessary in order to extrapolate animal data from PBPK models to the human. A study is in progress to examine anatomical differences for four species.     

Role of informal sector recycling in waste management in developing countries

Many thousands of people in developing country cities depend on recycling materials from waste for their livelihoods. With the focus of the Millennium Development Goals on poverty reduction, and of waste strategies on improving recycling rates, one of the major challenges in solid waste management in developing countries is how best to work with this informal sector to improve their livelihoods, working conditions and efficiency in recycling.The general characteristics of informal recycling are reviewed, highlighting both positive and negative aspects. Despite the health and social problems associated with informal recycling, it provides significant economic benefits that need to be retained. Experience shows that it can be highly counterproductive to establish new formal waste recycling systems without taking into account informal systems that already exist. The preferred option is to integrate the informal sector into waste management planning, building on their practices and experience, while working to improve efficiency and the living and working conditions of those involved. Issues associated with integrating informal recycling into the formal waste management sector are discussed.     

Teaching Disability Studies in Canada and the USA

Using a 1993 sample (n=107) of persons who teach disability studies courses, a sample (n=27) of disability studies syllabi from the early 1980s, and an extensive bibliography the authors discuss the history and the present condition of disability studies courses in the US and Canada. They discuss the disability paradigm and the methodology used in disability studies courses. The variety and geographical spread of such courses are noted. An extensive comparison of syllabi from the 1980s and the 1990s, including the reading assignments, is carried out.     

On the preservation of copula structure under truncation

The author characterizes the copula associated with the bivariate survival model of Clayton (1978) as the only absolutely continuous copula that is preserved under bivariate truncation.     

Pathways between education and health: a causal modelling approach

Summary.  The association of poor education and poor health has been consistently observed in many studies and in various countries. Thus far, studies examining the mechanisms underlying this association have looked at only a limited set of potential pathways. This study simultaneously examines six distinctive pathways, which have been hypothesized to link education and health and found support from previous studies. A causal analysis of education and health was performed using structural equation models. Data were used from six phases of the National Child Development Study, which is based on following up an initial sample of 17416 children who were born in 1958. The association between education and health appears to be explained by a combination of mechanisms: adolescent health and adult health behaviours for men and women, adult social class among men and parental social class among women. We conclude that improvements in population educational attainment may not automatically lead to improvements in population health, and that health policies for improving health and reducing health inequalities need to target specific causal pathways.     

Reclaiming the spirit: The journeys of gay men and lesbian women toward integration

The goal of this study is to understand and describe the way gay men and lesbian women see and interpret their spiritual journeys. Its intent is to open up the variety of experiences that gay men and lesbians encounter and is, therefore, not based on a single religious tradition or path, such as through crisis or AIDS. The findings included a model which interweaves the coming out process and the spiritual journey for this group of gay men and lesbian women, highlighting the period of questioning, reclaiming, and reintegration that happens for many as they resolve their sense of themselves as sexual and spiritual. Also addressed is the choice of mainstream and non-mainstream spiritual identification. The research discussed in this report was supported in part by the University Research Council, DePaul University.     

The employment contract: A test of the transaction cost theory

This paper tests some predictions derived from Williamson's transaction cost theory of the organization of work, which holds that the form of the employment relationship is determined largely by the idiosyncrasy of work—that is, the nature of skills and knowledge used in production. It examines the occurrence of theoretically relevant provisions in collective bargaining agreements in the United States and finds they are related to a contract-level proxy for idiosyncrasy (based on bargaining structure) as predicted by the theory. An analysis of an individual-level variable, the difficulty of finding a comparable job, provides some additional support. Finally, several alternative explanations of the results are considered, and it is argued that none are consistent with the evidence. The analysis thus finds strong, if necessarily provisional, support for the theory.     

Gender,academic careers,and the social psychology of aging

Because of cultural, historical and other social structural factors, men and women with the same chronological age have had quite different career trajectories. This paper examines how the different career-paths of men and women academics create differences in their images of aging, self and work. In-depth interviews (N=47) were conducted with a sample of male and female professors, currently between fifty and sixty years of age. Male respondents nearly uniformly followed continuous, linear careers while the women's careers were, with equal uniformity, discontinuous. Data suggest that this difference in career routes fashions different gender timeclocks, i.e., different experiences of aging.