Expert Scientific Judgment and Cancer Risk Assessment: A Pilot Study of Pharmacokinetic Data

When high-dose tumor data are extrapolated to low doses, it is typically assumed that the dose of a carcinogen delivered to target cells is proportional to the dose administered to test animals, even at exposure levels below the experimental range. Since pharmacokinetic data are becoming available that in some cases question the validity of this assumption, risk assessors must decide whether to maintain the standard assumption. A pilot study of formaldehyde is reported that was undertaken to demonstrate how expert scientific judgment can help guide a controversial risk assessment where pharmacokinetic data are considered inconclusive. Eight experts on pharmacokinetic data were selected by a formal procedure, and each was interviewed personally using a structured interview protocol. The results suggest that expert scientific opinion is polarized in this case, a situation that risk assessors can respond to with a range of risk characterizations considered biologically plausible by the experts. Convergence of expert opinion is likely in this case of several specific research strategies ar executed in a competent fashion. Elicitation of expert scientific judgment is a promising vehicle for evaluating the quality of pharmacokinetic data, expressing uncertainty in risk assessment, and fashioning a research agenda that offers possible forging of scientific consensus.     

Special Educational Needs: From Disciplinary to Pedagogic Research

A review of research on special educational needs in Britain over the last two decades indicates that two concerns have been paramount. First, there has been an attempt to broaden research styles in response to the growing critique of traditional positivist research. Secondly, the problem of the perceived gap between theory and practice has been addressed. Developments have included the use of small-N studies within a positivist framework, the adoption of qualitative research strategies and the critical perspectives of sociologists. It is argued here that such developments have been largely restricted to what Michael Bassey refers to as 'disciplinary' research, neglecting the 'pedagogic' research associated with the growth of practitioner research in other areas of education. The article examines both why teacher research has been relatively neglected in special education and the kinds of contributions it might make.     

At the intersection of idealized youth and marginalized almost-adulthood: how girls negotiate young motherhood in London,Ontario

This article discusses how young mothers in London, a mid-size city in Canada, utilize a drop-in centre service while attending an alternative programme to acquire secondary school credits. The central arguments made here are informed by key concepts in the field of girlhood studies. With its attention to the interconnections between gender, age, and generation as well as other aspects of social identity, girlhood studies provides crucial insight into the lived experiences of young mothers who straddle the space between girlhood and adulthood. We interpret the experiences of the young mothers who participated in this study in light of shifting meanings and expectations of girls and girlhood in the neoliberal era. Drawing on the concept of the ideal neoliberal girl subject embodied in the ‘can do’ and ‘at risk’ girl, this paper highlights the tensions in accessing a drop-in centre, which functions as both a site of security and surveillance, for a group of young mothers receiving social services. The findings revealed how girls who are mothers struggle to live in the present to assert a legitimate maternal identity even as they are prepared for the future through neoliberal public policies and other disciplinary practices.     

Reducing the Risk of Injury from Table Saw Use: The Potential Benefits and Costs of Automatic Protection

The use of table saws in the United States is associated with approximately 28,000 emergency department (ED) visits and 2,000 cases of finger amputation per year. This article provides a quantitative estimate of the economic benefits of automatic protection systems that could be designed into new table saw products. Benefits are defined as reduced health‐care costs, enhanced production at work, and diminished pain and suffering. The present value of the benefits of automatic protection over the life of the table saw are interpreted as the switch‐point cost value, the maximum investment in automatic protection that can be justified by benefit‐cost comparison. Using two alternative methods for monetizing pain and suffering, the study finds switch‐point cost values of $753 and $561 per saw. These point estimates are sensitive to the values of inputs, especially the average cost of injury. The various switch‐point cost values are substantially higher than rough estimates of the incremental cost of automatic protection systems. Uncertainties and future research needs are discussed.     

The EPA Health Risk Assessment of Methylcyclopentadienyl Manganese Tricarbonyl (MMT)

This paper describes the U.S. Environmental Protection Agency's assessment of potential health risks associated with the possible widespread use of a manganese (Mn)-based fuel additive, methylcyclopentadienyl manganese tricarbonyl (MMT). This assessment was significant in several respects and may be instructive in identifying certain methodological issues of general relevance to risk assessment. A major feature of the inhalation health risk assessment was the derivation of Mn inhalation reference concentration (RfC) estimates using various statistical approaches, including benchmark dose and Bayesian analyses. The exposure assessment component used data from the Particle Total Exposure Assessment Methodology (PTEAM) study and other sources to estimate personal exposure levels of particulate Mn attributable to the permitted use of MMT in leaded gasoline in Riverside, CA, at the time of the PTEAM study; on this basis it was then possible to predict a distribution of possible future exposure levels associated with the use of MMT in all unleaded gasoline. Qualitative as well as quantitative aspects of the risk characterization are summarized, along with inherent uncertainties due to data limitations.     

Implicit prejudicial biases in student learning: the effects of sexual orientation

In an investigation of students' potential biases toward gay and lesbian instructors, 93 female and 59 male undergraduates viewed a lecture, rated the instructor and perceived learning, and completed a lecture-retention test. Lectures were given by a man or woman, identified as straight or gay or lesbian. Sexual orientation did not affect the instructor evaluation or perceived learning ratings for any of the groups. Although sexual orientation did not affect the lecture-retention scores for the female students, learning by the male students was significantly lower with the gay male instructor than with the straight male instructor (p = .03), suggesting an implicit bias.     

Discourse Analysis in Career Counseling and Development

Discourse analysis can be used to understand and interpret culturally and socially produced meanings regarding work and to outline how specific rules and conventions can configure meaning production of work in context. The implications of some core concepts in discourse analysis pertinent to career counseling are explored, including discourse, deconstruction, power/knowledge, psy‐complex, ideology, and identity. Such an exploration has the potential to initiate a process of critical self‐reflection in career counseling and development so as to enhance ethical, fair, and inclusive practices in the field.     

Efficiency Bounds for Missing Data Models With Semiparametric Restrictions

This paper shows that the semiparametric efficiency bound for a parameter identified by an unconditional moment restriction with data missing at random (MAR) coincides with that of a particular augmented moment condition problem. The augmented system consists of the inverse probability weighted (IPW) original moment restriction and an additional conditional moment restriction which exhausts all other implications of the MAR assumption. The paper also investigates the value of additional semiparametric restrictions on the conditional expectation function (CEF) of the original moment function given always observed covariates. In the program evaluation context, for example, such restrictions are implied by semiparametric models for the potential outcome CEFs given baseline covariates. The efficiency bound associated with this model is shown to also coincide with that of a particular moment condition problem. Some implications of these results for estimation are briefly discussed.