Risk Management in a Polio-Free World

Inherent in the decision to launch the Global Polio Eradication Initiative in 1988 was the expectation for many people that immunization against poliomyelitis would eventually simply stop, as had been the case with smallpox following its eradication in 1977. However, the strategies for managing the risks associated with a "polio-free" world must be continuously refined to reflect new developments, particularly in our understanding of the live polioviruses in the oral poliovirus vaccine (OPV) and in the international approach to managing potential biohazards. The most important of these developments has been the confirmation in 2000 that vaccine-derived polioviruses (VDPVs) can circulate and cause polio outbreaks, making the use of OPV after interruption of wild poliovirus transmission incompatible with a polio-free world. A comprehensive strategy has been developed to minimize the risks associated with eventual OPV cessation, centered on appropriate long-term biocontainment of poliovirus stocks (whether for vaccine production, diagnosis, or research), the controlled reintroduction of any live poliovirus vaccine (i.e., from an OPV stockpile), and appropriate use of the inactivated poliovirus vaccine (IPV). Although some aspects of this risk management strategy are still debated, there is wide agreement that no strategy would entirely eliminate the potential risks to a polio-free world. The current strategy for risk management in a polio-free world will continue to evolve with better characterization of these risks and the development of more effective approaches both to reduce those risks and to limit their consequences should they occur.     

Social Guardianship and Social Isolation: An Application and Extension of Lifestyle/Routine Activities Theory to Rural Adolescents*

Abstract Although the overall crime rate dropped between 1993 and 2000, both adolescent violence and violent crime in rural areas has been on the rise. However, little research has been conducted on the determinants of rural violence using targeted regional samples of rural youth. This study examines the applicability of lifestyle/routine activities (RA) theory to a large sample of rural adolescents from Alabama. Multivariate logistic regression analyses indicate that: (1) social guardianship reduces the risk of assault and robbery victimization; (2) blacks are less likely to be assault and robbery victims; and (3) males are less likely to be robbery victims. Social isolation at the individual level is also a strong risk factor for both robbery and assault victimization. The theoretical implications of these findings and suggestions for future research are also discussed.     

OSHA''s Permissible Exposure Limits: Regulatory Compliance Versus Health Risk

Workplace exposures to airborne chemicals are regulated in the U.S. by the Occupational Safety and Health Administration (OSHA) via the promulgation of permissible exposure limits (PELs). These limits, usually defined as eight-hour time-weighted average values, are enforced as concentrations never to be exceeded. In the case of chronic or delayed toxicants, the PEL is determined from epidemiological evidence and/or quantitative risk assessments based on long-term mean exposures or, equivalently, cumulative lifetime exposures. A statistical model was used to investigate the relation between the compliance strategy, the PEL as a limit never to be exceeded, and the health risk as measured by the probability that an individual's long-term mean exposure concentration is above the PEL. The model incorporates within-worker and between-worker variability in exposure, and assumes the relevant distributions to be log-normal. When data are inadequate to estimate the parameters of the full model, as it is in compliance inspections, it is argued that the probability of a random measurement being above the PEL must be regarded as a lower bound on the probability that a randomly selected worker's long-term mean exposure concentration will exceed the PEL. It is concluded that OSHA's compliance strategy is a reasonable, as well as a practical, means of limiting health risk for chronic or delayed toxicants.     

DOING THERAPY: A POST-STRUCTURAL RE-VISION*

The purpose of this essay is to develop a way to look at doing therapy based on (a) Wittgenstein's concept of “language game”; (b) the relationship between Wittgenstein's “private language” argument, language games, and constructivism; and (c) post-structural thinking about language, how therapy works within language, and how language works within therapy. Case material is used to illustrate the usefulness of this approach.     

Exploring the Meaning of Rural Through Cognitive Maps1

Rural often is viewed as a setting for study rather than an object of study. Often a priori definitions of rural are used; these definitions may bear little resemblance to residents' understanding of the concept. A cognitive mapping experiment to explore the meaning of rural is undertaken in this paper. Results indicate that urban residents could readily identify rural areas on a blank map of Pennsylvania. Their responses to the question varied, however, with some respondents indicating urban areas or writing images on the map. A discussion of these thought processes and implications from these varying responses are presented. Then, the cognitive maps are compared to three commonly accepted definitions of rural. Population density was found to best approximate the areas that urban residents perceived as rural. The paper concludes by discussing policy implications of the findings.     

Modeling Benzene Pharmacokinetics Across Three Sets of Animal Data: Parametric Sensitivity and Risk Implications

Typically, the uncertainty affecting the parameters of physiologically based pharmacokinetic (PBPK) models is ignored because it is not currently practical to adjust their values using classical parameter estimation techniques. This issue of parametric variability in a physiological model of benzene pharmacokinetics is addressed in this paper. Monte Carlo simulations were used to study the effects on the model output arising from variability in its parameters. The output was classified into two categories, depending on whether the output of the model on a particular run was judged to be generally consistent with published experimental data. Statistical techniques were used to examine sensitivity and interaction in the parameter space. The model was evaluated against the data from three different experiments in order to test for the structural adequacy of the model and the consistency of the experimental results. The regions of the parameter space associated with various inhalation and gavage experiments are distinct, and the model as presently structured cannot adequately represent the outcomes of all experiments. Our results suggest that further effort is required to discern between the structural adequacy of the model and the consistency of the experimental results. The impact of our results on the risk assessment process for benzene is also examined.     

Using a Consultant Workshop Model to Improve Performance Management in Chinese Autism Agencies: A Preliminary Study

ABSTRACT

This study investigated the outcomes of using a consultant workshop model to help implement performance management (PM) methods in selected Chinese autism agencies. A need for improvement of educational services in Chinese autism agencies was identified. However, the theory and methods of organizational behavior management (OBM) in general and PM in particular are still foreign in the Chinese autism community. The primary research question of the current study was whether first-line teacher performance in Chinese autism agencies could be improved by the use of a consultant workshop model to train management staff to implement a PM system. Four autism agencies in different Chinese provinces participated in this study. Results demonstrated that after the implementation of the PM system through a consultant workshop model in the participating agencies, the performance of first-line teachers in these agencies improved in several important areas. The intervention appeared modestly effective. Implications of the outcome data and future directions for practitioners and researchers are discussed.