Physiologically Based Liver Modeling and Risk Assessment

Because of the inherent complexity of biological systems, there is often a choice between a number of apparently equally applicable physiologically based models to describe uptake and metabolism processes in toxicology or risk assessment. These models may fit the particular data sets of interest equally well, but may give quite different parameter estimates or predictions under different (extrapolated) conditions. Such competing models can be discriminated by a number of methods, including potential refutation by means of strategic experiments, and their ability to suitably incorporate all relevant physiological processes. For illustration, three currently used models for steady-state hepatic elimination--the venous equilibration model, the parallel tube model, and the distributed sinusoidal perfusion model--are reviewed and compared with particular reference to their application in the area of risk assessment. The ability of each of the models to describe and incorporate such physiological processes as protein binding, precursor-metabolite relations and hepatic zones of elimination, capillary recruitment, capillary heterogeneity, and intrahepatic shunting is discussed. Differences between the models in hepatic parameter estimation, extrapolation to different conditions, and interspecies scaling are discussed, and criteria for choosing one model over the others are presented. In this case, the distributed model provides the most general framework for describing physiological processes taking place in the liver, and has so far not been experimentally refuted, as have the other two models. These simpler models may, however, provide useful bounds on parameter estimates and on extrapolations and risk assessments.     

The relationship between paid work and parenthood--a comparison of structures,concepts and developments in the UK and Austria

This article investigates and compares the dominant concepts of public policy concerning the employment-parenthood interface in the UK and Austria. These two countries have been chosen because they represent very different public policy conceptions, particularly in approaching the work-family issue. In order to show the consequences of these policies the paper focuses on working time and time away from employment, when children are very young, and relates these aspects to currently introduced and changed regulatory structures, such as working time regulations and statutory parental leave. The active labour market and family policy in Austria, generally, supports the reconciliation of employment and parenthood. However, the Austrian work-family 'system' suffers from the underlying notion of the male breadwinner model in public support structures and low normative support of employed mothers. The cultural barriers for a more equal distribution of the burdens of combining employment and parenthood seem to be lower in the UK. The market as the political focus, in general, allows more equal opportunities for (qualified) women in the labour market and within families. But the highly flexible and polarised labour market, passive public policy and weak legal protection of employed parents creates a difficult relationship between paid work and family life for many parents, in particular for low-skilled, low-paid parents, above all mothers. These analyses provide the basis for conclusions for public policy aiming at the reconciliation of paid work and parenthood. Ce texte cherche à comparer les concepts dominants de la politique gouvernementale concernant l'interface travail-parent en Grande-Bretagne et en Autriche. Ces deux pays ont été choisis parce qu'ils présentent des concepts de politique gouvernementale très différents, en particulier en ce qui concerne la question de la famille et le travail. Ce texte montre les conséquences de la pratique de ces politiques sur le temps au travail rémunéréet le temps passé à l'extérieur de l'emploi ou sans emploi, et ce, dans un contexte o[ugrave] les enfants sont jeunes. Le texte fait la relation entre ces éléments et la pratique des structures de contrôle existantes et modifiées telles que les lois (ou: les règlements) sur le temps passéau travail et sur les congé parentaux. En général, le marché du travail et la politique de la famille en Autriche encourage la conciliation entre l'emploi et la responsabilité de parent. Par contre, ce système de travail- famille autrichien est un concept qui est fondé à la fois sur le modèle de l'homme comme fournisseur principal du revenu familial dans les structures de soutien public ainsi que sur normes de soutien peu élevées pour les mères employées. Les barrières culturelles face àune distribution plus égalitaire de la responsabilité travail-famille semblent être moins élevées en Grande-Bretagne. En général, le marché et la politique du marché du travail ont offerts plus d'opportunités aux femmes qualifiées. Mais la volatilité (et la polarisation) du marché du travail, la politique gouvernementale passive et la faible protection légale pour les parentstravailleurs créent tous une relation difficile pour les parents entre le travail rémunéré et la vie de famille--en particulier pour ceux qui sont moins qualifiés et mal rémunérés, dont surtout les mères de famille. Cette analyse nous guide vers la nécessité d'une politique gouvernementale qui vise la conciliation entre le travail rémunéré et la responsabilité parentale.     

Surname analysis for estimating local concentration of Hispanics and Asians

Surname analysis is a potentially useful technique for identifying members of particular racial, ethnic, or language communities within a population. We review the existing state of the art for identifying persons of Hispanic or Asian origin, based on surnames distinctive of each group. We describe the logic of surname analysis, profile several available surname dictionaries, and illustrate their applications in local redistricting. Results of our ongoing validation studies suggest promising future directions for improving accuracy and broadening applications.This article is based on a paper presented at the annual Population Association of America meetings at Cincinnati, 1 April 1993.     

Race and prevailing wage laws in the construction industry: Comment on Thieblot

Using the 1990 Census of Population, Thieblot (1999) argued that black employment and the strength of the prevailing wage laws are correlated and that repeal of these laws would lead to higher black employment in construction. Analysis of the 1970 Census of Population reveals that the relative abundance of black construction workers in the group of states that eventually would repeal their laws preceded those repeals and that this is mainly due to the characteristics of Southern labor markets. This and other research cast doubt on both the strength and the existence of such a correlation.     

Optimal sampling for repeated binary measurements

The authors consider the optimal design of sampling schedules for binary sequence data. They propose an approach which allows a variety of goals to be reflected in the utility function by including deterministic sampling cost, a term related to prediction, and if relevant, a term related to learning about a treatment effect To this end, they use a nonparametric probability model relying on a minimal number of assumptions. They show how their assumption of partial exchangeability for the binary sequence of data allows the sampling distribution to be written as a mixture of homogeneous Markov chains of order k. The implementation follows the approach of Quintana & Müller (2004), which uses a Dirichlet process prior for the mixture.     

Earnings of Chinese Immigrants in the Enclave and Mainstream Economy*

La documentation sur le sujet n'est pas décisive quant à savoir si léconomie ethnique enclavée enregistre un rendement économique comparable chez les travailleurs et les entrepreneurs immigrants à ceux qui se situent dans le courant économique principal. Les auteurs de cette étude utilisent des données du Recensement du Canada de 2001 sur la langue la plus utilisée au travail din de mesurer la participation des immigrants chinois à léconomie enclavée. Après les avoir comparés au capital humain ainsi qu'aux variations liées au travail et au milieu urbain, les résultats démontrent que le rendement est moins élevé chez les hommes et chez les femmes de l'enclave que celui des gens qui se trouvent dans le courant économique principal. Les caractéristiques de la langue et le type de travail qui s'effectue dans léconomie enclavée expliquent pourquoi le rendement y est inférieur à celui obtenu dans le courant économique principal. The literature in inconclusive as to whether the immigrant enclave economy offers returns to immigrant workers and entrepreneurs comparative to those in the mainstream economy. This study uses data from the 2001 Census of Canada on language most often used at work to measure enclave economy participation for Chinese immigrants. The findings show that returns are lower for men or women in the enclave than those in the mainstream economy, respectively, after controlling for human capital, work‐related and urban variations. Language features of and job type in the enclave economy explain why returns are inferior to that of the mainstream economy.