Development of a Screening Approach to Interpret Human Biomonitoring Data on Volatile Organic Compounds: Reverse Dosimetry on Biomonitoring Data for Trichloroethylene

A screening approach is developed for volatile organic compounds (VOCs) to estimate exposures that correspond to levels measured in fluids and/or tissues in human biomonitoring studies. The approach makes use of a generic physiologically-based pharmacokinetic (PBPK) model coupled with exposure pattern characterization, Monte Carlo analysis, and quantitative structure property relationships (QSPRs). QSPRs are used for VOCs with minimal data to develop chemical-specific parameters needed for the PBPK model. The PBPK model is capable of simulating VOC kinetics following multiple routes of exposure, such as oral exposure via water ingestion and inhalation exposure during shower events. Using published human biomonitoring data of trichloroethylene (TCE), the generic model is evaluated to determine how well it estimates TCE concentrations in blood based on the known drinking water concentrations. In addition, Monte Carlo analysis is conducted to characterize the impact of the following factors: (1) uncertainties in the QSPR-estimated chemical-specific parameters; (2) variability in physiological parameters; and (3) variability in exposure patterns. The results indicate that uncertainty in chemical-specific parameters makes only a minor contribution to the overall variability and uncertainty in the predicted TCE concentrations in blood. The model is used in a reverse dosimetry approach to derive estimates of TCE concentrations in drinking water based on given measurements of TCE in blood, for comparison to the U.S. EPA's Maximum Contaminant Level in drinking water. This example demonstrates how a reverse dosimetry approach can be used to facilitate interpretation of human biomonitoring data in a health risk context by deriving external exposures that are consistent with a biomonitoring data set, thereby permitting comparison with health-based exposure guidelines.     

Knowledge and Attitudes of University Health Service Clients about Genital Herpes: Implications for Patient Education and Counseling

Abstract

Genital herpes virus infection is an important target for health education efforts because of its apparently rising incidence in the college student population and because it can have potentially serious psychological as well as medical consequences. In order to better understand the health education and counseling needs of students, the present study surveyed knowledge and attitudes about genital herpes of 190 university students using a gynecology clinic and of 161 students using a general medical clinic. The students were found to have a high degree of familiarity with the disease, its cause, and mode of transmission, but tended to view the consequences of the disease as more severe than is actually warranted by the common medical complications. There was some degree of misinformation about prevention and treatment of the disease and some negative attitudes about patients suffering from it, but the survey respondents endorsed a high level of responsible behavior with regard to the disease and expressed some optimism about the possibility of adapting to it. These findings suggest specific misconceptions about genital herpes that might be amenable to a mass education approach. They also suggest the need for a counseling program that centers around reasonable reassurance and appropriately positive psychological and medical management for newly diagnosed patients.     

Modeling large electorates with Fourier series, with applications to Nash equilibria in proximity and directional models of spatial competition

 In this paper we introduce harmonic analysis (Fourier series) as a tool for characterizing the existence of Nash equilibria in two-dimensional spatial majority rule voting games with large electorates. We apply our methods both to traditional proximity models and to directional models. In the latter voters exhibit preferences over directions rather than over alternatives, per se. A directional equilibrium can be characterized as a Condorcet direction, in analogy to the Condorcet (majority) winner in the usual voting models, i.e., a direction which is preferred by a majority to (or at least is not beaten by) any other direction. We provide a parallel treatment of the total median condition for equilibrium under proximity voting and equilibrium conditions for directional voting that shows that the former result is in terms of a strict equality (a knife-edge result very unlikely to hold) while the latter is in terms of an inequality which is relatively easy to satisfy. For the Matthews [3] directional model and a variant of the Rabinowitz and Macdonald [7] directional model, we present a sufficiency condition for the existence of a Condorcet directional vector in terms of the odd-numbered components of the Fourier series representing the density distribution of the voter points. We interpret our theoretical results by looking at real-world voter distributions and direction fields among voter points derived from U.S. and Norwegian survey data. Received: 7 July 1995 / Accepted: 14 May 1996     

Palestinian Society

Conclusion Several observations are in order. One is that despite a considerable divergence in the points of view, the authors of the works under review share a single language and methodology, that of the modern social sciences, and a common commitment to understanding Palestinian society. There is a significant overlap of subject matter as well. It is not always possible to infer the personal sympathies of the author from his or her essay.Since the illusion of a Palestinian military threat to Israel has been dispelled, these volumes' lasting contribution is the findings they provide on the political economy of Palestinian society. The Palestinian's future on the West Bank and in Gaza will depend on the differential impact of these territories' incorporation into the Israeli economy on specific groups within the society, as well as by Israeli policies of control, and the will and capacity of the Palestinians to resist them. The work of Tamari, Graham-Brown, Taqqu, Lustick, Migdal, and others contained in the volumes under review here provides a necessary perspective from which to observe events. To the extent that the complex dispute between Israelis and Palestinians turns on the land question, the specific ways in which land is alienated and peasant populations are transformed into workers has a major bearing on ultimate outcomes.Consideration of Palestinian society raises significant theoretical issues. These include the impact upon agricultural societies of their integration into the capitalist world market, the role of the state in the rule of minorities, the study of elite factionalism, and the development of national consciousness. The findings of the works on Palestinian society suggest the following hypotheses: that agricultural populations respond to the market in differential ways, which can work against the emergence of both nationalist and working class consciousness; that the policies adopted by states confronted with highly politicized minorities can have significant impacts; that factionalism is a product of state policy choices (and not foreordained), and that national consciousness does not diminish (and may increase) with economic incorporation. The recent literature on Palestinian society thus has strategic contributions to make to the social sciences.Finally, in studying Palestinian society, we come to grips more directly than we might in a less highly conflicted subject with the problematic epistemological grounds on which the social sciences are erected. Here we can see (somewhat more clearly than normally) the ways in which the questions asked by social scientists derive from their positions in the political and intellectual fields of their societies. This may be a salutary and sobering experience.

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Does Social Capital Make You Generous?*

Objectives. This article tests the hypothesis that social capital—measured in terms of civic group involvement, social and racial trust, and political engagement—leads to charitable behavior by individuals. Methods. I introduce measures of the “social capital elasticity of giving,” which facilitate comparisons between the effects on charity of different social capital types. Using data from the 2000 Social Capital Community Benchmark Survey, I estimate these elasticities with tobit regression models. Results. I find strong links between changes in social capital stocks and changes in giving levels. Furthermore, I find that different social capital types have differing levels of impact on giving. Conclusions. Charitable giving appears to be a beneficial consequence of some types of social capital.