Dose-Response Assessment of Airborne Methyl Isothiocyanate (MITC) Following a Metam Sodium Spill

A tank car derailment in northern California in 1991 spilled metam sodium into the Sacramento River, and released its breakdown product, methyl isothiocyanate (MITC), into the air. This paper describes the risk evaluation process used. Over 240 individuals reported symptoms such as eye and throat irritation, dizziness, and shortness of breath. Reference exposure levels (RELs) for 1 hr were developed for MITC and compared to exposure concentrations. Ocular irritation in cats was the most sensitive endpoint reported. The no observed adverse effect level (NOAEL), divided by an uncertainty factor (UF) of 100, produced an REL of 0.5 ppb of MITC in air to prevent discomfort. An REL to prevent disability was estimated to be 40 ppb. An REL to prevent life-threatening injury was estimated to be 150 ppb. Measured MITC levels ranged from 0.2-37 ppb and estimated peak levels ranged from 140-1600 ppb. The usefulness of RELs for emergency planning is discussed.     

A Methodology for Seismic Risk Analysis of Nuclear Power Plants

This methodology begins by quantifying the fragility of all key components and structures in the plant. By means of the logic encoded in the plant event trees and fault trees, the component fragilities are combined to form fragilities for the occurrence of plant damage states or release categories. Combining these, in turn, with the seismicity curves yields the frequencies of those states or releases. Uncertainty is explicitly included at each step of the process.     

A model system: Integrated work injury prevention and disability management

Effective and cost efficient work injury prevention and disability management requires an integrated process that involves a number of components. Each component needs to be linked into a continuum or system. Components by themselves will not provide satisfactory solutions. This article addresses some of the key components that need to be included in an effective work injury management system. The goals of a management system are discussed and how each component plays a part in achieving these goals.     

The influence of macroeconomic variables on the probability of union decertification

This study focuses on the role macroeconomic factors play in explaining the proportion of decertification elections lost by the union movement in the postwar period. Previous research has neglected the importance of such macroeconomic variables. Our results indicate that the union-nonunion wage differential, inflation, strikes, state of the labor market, and union density are related to the phenomenon of decertification. The authors would like to thank Greg Hundley, Mike Bognanno, Paul Schumann, Jim Scoville, the editor, and a reviewer for valuable comments and Michael Wachter and William Wascher for providing some unpublished data.     

Jackknifing in Categorical Data Analysis

Estimation of nonlinear functions of a multinomial parameter vector is necessary in many categorical data problems. The first and second order jackknife are explored for the purpose of reduction of bias. The second order jackknife of a function g(.) of a multinomial parameter is shown to be asymptotically normal if all second order partials ?²g( p )?dp_i?p_j obey a Hölder condition with exponent α>1/2. Numerical results for the estimation of the log odds ratio in a 2times2 table demonstrate the efficiency of the jackknife method for reduction of mean-square-error and the construction of approximate confidence intervals.     

Reports of childhood sexual abuse by adolescents and young adults: stability over time

The consistency of childhood sexual abuse (CSA) reporting was explored in this study. Two-hundred seventeen adolescents and young adults (ages 14-24) enrolled in urban health care clinics completed self-report questionnaires assessing CSA and other problem behaviors at enrollment and at 7 months. Results indicated that the stability of CSA self-report at two time points was poor (58% consistent nonreporters of CSA, 20% consistent reporters, 22% inconsistent reporters). Consistent and inconsistent reporters were differentiated on risk measures. Adolescents who endorsed more items from the CSA scale were five times more likely to be consistent reporters. In sum, adolescent CSA reporting was quite inconsistent over time. Using multi-item scales and assessing CSA at two time points enhances accuracy of reporting.     

Mismatch of school desks and chairs by ethnicity and grade level in middle school

The purpose of this article is to introduce the cross-disciplinary competency standards for work-related assessments, why they are needed and how they have been developed in New South Wales (NSW). Cross-disciplinary competency standards communicate the benchmarks for effective performance of work-related assessments. They outline what is expected of rehabilitation professionals, including the ability to apply and transfer competence across different conditions and workplace contexts. Outcomes in occupational rehabilitation are affected by the efficacy of the work-related assessments performed, which is dependent upon competent, clinical decision-making by rehabilitation professionals. However, in Australia, work-related assessment practice is not governed by universally accepted competency standards or by any competency-based training/education and assessment system. To enhance professional practice, WorkCover NSW has developed cross-disciplinary competency standards for work-related a ssessments. The competencies provide (i) quality standards for professional workplace training and development, (ii) benchmarks for assessing the competence of rehabilitation professionals, (iii) a framework for evidence-based practice, (iv) benchmarks for measuring service quality and (v) "real world" learning outcomes and assessment criteria for professional education programs.     

New Data,Strategies, and Insights for Listeria monocytogenes Dose‐Response Models: Summary of an Interagency Workshop, 2011

Listeria monocytogenes is a leading cause of hospitalization, fetal loss, and death due to foodborne illnesses in the United States. A quantitative assessment of the relative risk of listeriosis associated with the consumption of 23 selected categories of ready‐to‐eat foods, published by the U.S. Department of Health and Human Services and the U.S. Department of Agriculture in 2003, has been instrumental in identifying the food products and practices that pose the greatest listeriosis risk and has guided the evaluation of potential intervention strategies. Dose‐response models, which quantify the relationship between an exposure dose and the probability of adverse health outcomes, were essential components of the risk assessment. However, because of data gaps and limitations in the available data and modeling approaches, considerable uncertainty existed. Since publication of the risk assessment, new data have become available for modeling L. monocytogenes dose‐response. At the same time, recent advances in the understanding of L. monocytogenes pathophysiology and strain diversity have warranted a critical reevaluation of the published dose‐response models. To discuss strategies for modeling L. monocytogenes dose‐response, the Interagency Risk Assessment Consortium (IRAC) and the Joint Institute for Food Safety and Applied Nutrition (JIFSAN) held a scientific workshop in 2011 (details available at http://foodrisk.org/irac/events/ ). The main findings of the workshop and the most current and relevant data identified during the workshop are summarized and presented in the context of L. monocytogenes dose‐response. This article also discusses new insights on dose‐response modeling for L. monocytogenes and research opportunities to meet future needs.