Immigrants' Language Skills and Visa Category1

This article is concerned with the determinants of English language proficiency among immigrants in a longitudinal survey for Australia. It focuses on both visa category and variables derived from an economic model of the determinants of destination‐language proficiency among immigrants. Skills‐tested and economic immigrants have the greatest proficiency shortly after immigration, followed by family‐based visa recipients, with refugees having the lowest proficiency. Other variables the same, these differences disappear by 3.5 years after immigration for speaking skills; and although they diminish, they persist longer for reading and writing skills. The variables generated from the model of destination‐language proficiency (such as schooling and age at migration) are, in part, predictions of visa category, but they are more important statistically for explaining proficiency.     

Intuitive Toxicology: Expert and Lay Judgments of Chemical Risks

Human beings have always been intuitive toxicologists, relying on their senses of sight, taste, and smell to detect harmful or unsafe food, water, and air. As we have come to recognize that our senses are not adequate to assess the dangers inherent in exposure to a chemical substance, we have created the sciences of toxicology and risk assessment to perform this function. Yet despite this great effort to overcome the limitations of intuitive toxicology, it has become evident that even our best scientific methods still depend heavily on extrapolations and judgments in order to infer human health risks from animal data. Many observers have acknowledged the inherent subjectivity in the assessment of chemical risks and have indicated a need to examine the subjective or intuitive elements of expert and lay risk judgments. We have begun such an examination by surveying members of the Society of Toxicology and the lay public about basic toxicological concepts, assumptions, and interpretations. Our results demonstrate large differences between toxicologists and laypeople, as well as differences between toxicologists working in industry, academia, and government. In addition, we find that toxicologists are sharply divided in their opinions about the ability to predict a chemical's effect on human health on the basis of animal studies. We argue that these results place the problems of risk communication in a new light. Although the survey identifies misconceptions that experts should clarify for the public, it also suggests that controversies over chemical risks may be fueled as much by limitations of the science of risk assessment and disagreements among experts as by public misconceptions.     

Russki adventures

This case study, by Paul Beamish, was a prize-winner in the EFMD 1992 Annual Case Writing Competition, in the section entitled, ‘Entrepreneurship’. It concerns a daring new business venture in the Russian Caucasus Mountains.In mid-1991, Guy Crevasse and Andrei Kakov, the two major partners in Russki Adventures contemplated their next move. They had spent the last year and a half exploring the possibility of starting a helipcopter skiing operation in Russia.Their plan was to bring clients from Europe, North America, and Japan to the Caucasus Mountains to ski the vast areas of secluded mountain terrain made accessible by the use of helicopters and the recent business opportunities offered by ‘glasnost’.Three options for proceeding were being considered. The first was to proceed with the venture on their own, in the Caucasus Mountains area that had been made available to them by a Soviet government agency. The second was to accept the offer of partnership with Extreme Dreams, a French tour operator that had begun operations in the Caucasus region during the 1991 season. The final option was to wait, save their money and not proceed with the venture at this time.The data presented in the case includes information on: the company founders the helicopter skiing industry the Russian environment proposed market positioning of the business the potential alliance partners forecast financial analysis, under several scenarios.     

Exposure Reconstruction for the TCDD-Exposed NIOSH Cohort Using a Concentration- and Age-Dependent Model of Elimination

Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more highly exposed members of the cohort compared to estimates obtained using the first-order model with 8.7-year half-life. This degree of variation in the AUC estimates for this cohort would affect substantially the cancer potency estimates derived from the mortality data from this cohort. Such variability and uncertainty in the reconstructed serum lipid AUC estimates for this cohort, depending on elimination model, parameter set, and regression model, have not been described previously and are critical components in evaluating the dose-response data from the occupationally exposed populations.     

A Numerical Solution to the Nonhomogeneous Two-Stage MVK Model of Cancer

In this article, we describe a straightforward method for solving the probability of at least one malignant cell by time t, and the associated hazard function, in the general (i.e., nonhomogeneous) two-stage Moolgavkar-Venzon-Knudson (MVK) model of cancer. The method consists of solving four coupled ordinary differential equations derived from the Kolmogorov backward equations for this process. The relationship of this method to previously proposed solutions is discussed.     

中国蒙古文学史料学的起始与发展

蒙古文学研究的基础和前提是蒙古文学史料。随着国内外蒙古文学研究的不断拓展和深入,蒙古文学史料搜集整理已逐步发展成为蒙古文学史料学。蒙古文学史料学包括蒙古文学的田野调查、史料整理、考订、选录、笺释、校注、校勘、辑评等诸多研究内涵。中国蒙古文学研究取得巨大成就,得益于蒙古文学史料学的长足发展。我们应当总结以往蒙古文学史料学研究的经验,使蒙古文学史料学更加系统化、科学化和理论化。     

Pathways between education and health: a causal modelling approach

Summary.  The association of poor education and poor health has been consistently observed in many studies and in various countries. Thus far, studies examining the mechanisms underlying this association have looked at only a limited set of potential pathways. This study simultaneously examines six distinctive pathways, which have been hypothesized to link education and health and found support from previous studies. A causal analysis of education and health was performed using structural equation models. Data were used from six phases of the National Child Development Study, which is based on following up an initial sample of 17416 children who were born in 1958. The association between education and health appears to be explained by a combination of mechanisms: adolescent health and adult health behaviours for men and women, adult social class among men and parental social class among women. We conclude that improvements in population educational attainment may not automatically lead to improvements in population health, and that health policies for improving health and reducing health inequalities need to target specific causal pathways.     

Evaluation: Stakeholder-focused Criteria

Identifying and selecting suitable criteria is an important consideration in evaluating the performance of public sector organizations. Which criteria are chosen, and how they are weighted, will depend largely on the perspective being taken; different stakeholders (for example, clients, providers or commissioners) are likely to emphasize different criteria. In this paper a number of criteria are identified and an argument is developed to indicate which criteria are likely to be valued by various stakeholders. Furthermore, a number of approaches and mechanisms for evaluation are identified and the links between these, the criteria appropriate to them and the various stakeholders are made explicit. Finally, the issue of politics and the distribution of power between the stakeholders is addressed with a call for greater explicitness in using and balancing criteria (for example, as between professionals and the intended beneficiaries of services). In this way, while recognizing the inherent political nature of performance evaluation, the planning and implementation of services may be improved by a more mutually informed approach to evaluation.     

The impact of social networks on the occupational status of migrants

This paper postulates that there is a continuous exchange of information and knowledge between those who share the common bond of having migrated to the US. The individual components of this information exchange constitute social networks. The 2 hypotheses tested are 1) immediate social networks and people known in the US facilitate the flow of information both to new migrants and between established migrants, thus promoting upward social mobility; and 2) access to broader network ties, organization membership, extra-ethnic friendships, and familiarity with established institutions smooths the transition process, resulting in increased social position. The data used comes from a study conducted in 1982-1983 in 4 Mexican sending communities (2 rural, 2 urban), for a total of 440 migrants. Results show that migrants in every socioeconomic bracket reported access to some or all social network characteristics. There was contact with either a family member or acquaintances from the migrants' town of origin. Over 50% of migrants reported knowing many fellow townspeople. Twice as many migrants belong to a sports club as to a social or religious organization. Very few rural migrants report knowing no townspeople, while 32% of urban migrants claim no knowledge of fellow migrants from their town of origin. Urban origin migrants report more contacts with those of other ethnicity than rural migrants. Those employed in agriculture are least acquainted with social information and contacts, while those in skilled and service sectors are well acquainted with them. The results of fact and analysis show that 1) access to personal US networks results in an average 4.4 point advantage in occupational prestige scores over no access, and 2) utilizing institutional US networks combined with any cumulative US experience gives a migrant a 5 point advantage over a fellow migrant with identical experience level but no institutional network contacts. This is also true for institutional Mexican networks. Thus success or failure in migrating is partly due to migrants' societal infrastructure and the fact that available information and social networks are accessed and utilized differently by different migrants.     

Assimilation process and group integration of migrant families

This empirical analysis gives 1st answers to the question of which effects some specific types of interaction structures within migrant families have on the assimilation process of family members and their personal integration. The analysis is based on a sample of 92 Turkish women and 123 Turkish men in the Bonn-Cologne area of West Germany. Questionnaires examine variables such as 1) urbanization of the context of origin, 2) household complexity, 3) availability of ethnic infrastructure, 4) residential proximity of Turkish friends and relatives; 5) school education of respondent and spouse; and 6) occupational prestige before migration. The study considers the following dimensions of social and cultural assimilation: 1) housing quality, 2) use of ethnic and general infrastructure, and 3) use of ethnic minority and mainstream cultural facilities. Results of empirical analyses on the housing conditions of migrants show that 1) motivational factors of the migrant family are unrelated to choice of a housing area, but are related to apartment quality; and 2) housing conditions differ markedly, depending on the type of combination of task-allocation and decision-making power in the family. Use of infrastructure 1) declines in Turkish families in which women's participation in family tasks is relatively high, 2) is determined most by the opportunity structure of the housing area and the interaction structure within the family; and 3) is a necessary step between the reorganization of the family's interaction structure and the participation in a broader spectrum of institutions of the receiving society. The family structure has no significant effect on participation in the minority culture. The extent of minority-culture rise has no direct relationship to the individual assimilation of family members. The empirical data support the basic theoretical assumption that the group integration of the migrant family has considerable effects on the assimilation process of its individual members. In conclusion, 1) opportunities for assimilation are increased by the combined resources of the migrants family household, and 2) continuing individual autonomy contributes severely to a reduced personal integration.