Enclaves, neighbourhood effects and employment outcomes: Ethnic minorities in England and Wales

Ethnic minorities in England and Wales are spatially concentrated in relatively-deprived urban areas. Both geographic clustering and the economic characteristics of ethnically-concentrated neighbourhoods can impact upon the opportunities and constraints facing residents of such areas. This paper explores the relationship between the existence of enclaves and the employment prospects of ethnic minorities in England and Wales. It is shown that there is considerable spatial variation in employment outcomes. There is a lower incidence of self-employment in more ethnically-concentrated urban areas, which contradicts the view of ethnic entrepreneurship as an enclave phenomenon. Unemployment rates are also higher for minorities living in more concentrated areas. Enclaves in England and Wales do not appear to offer many economic benefits to minority individuals. Received: 31 December 1999/Accepted: 27 November 2000     

浅议我国木材国际贸易的比较优势

在世贸组织体制下 ,我国木材国际贸易的环境将发生重大变化。木材国际贸易对缓解我国森林资源紧张矛盾 ,促进木材产业适应国际竞争要求 ,提高产业竞争力具有重要意义。我国木材产业在我国产业体系中处于相对落后位置 ,但不等于其产品完全没有国际贸易的比较优势。该文主要通过对我国木材产业部分产品贸易比较优势的分析 ,说明我国木材产业部分产品参与国际竞争的可能性和现实性。同时 ,提出我国保持现有产品比较优势和培育新的产品比较优势的战略立足点     

Ambivalences: a challenge to permanency for children

A key to determining a permanent plan for children in placement lies in determining and working with the history and relative intensity of parental ambivalence in the parent-child relationship as it is acted out in the placement experience. A study of cases in a public department disclosed not only indicators of parental ambivalence but also the reinforcement of that ambivalence by agency policy, working conditions, and lack of resources.     

An iterative Monte Carlo method for nonconjugate Bayesian analysis

The Gibbs sampler has been proposed as a general method for Bayesian calculation in Gelfand and Smith (1990). However, the predominance of experience to date resides in applications assuming conjugacy where implementation is reasonably straightforward. This paper describes a tailored approximate rejection method approach for implementation of the Gibbs sampler when nonconjugate structure is present. Several challenging applications are presented for illustration.     

Low-Income Children's Participation in a Public Health Insurance Program in Georgia

To expand health care coverage to uninsured, low-income children, the Congress created the State Children's Health Insurance Program (SCHIP) in 1997. Given ample evidence that state Medicaid programs have failed to enroll many eligible children, experts questioned whether SCHIP could successfully enroll low-income children. Using Georgia state SCHIP data, we analyzed enrollment patterns and identified factors contributing to program enrollment. This study found that the children's enrollment is explained by perceived costs and benefits of joining the program as well as the underlying family structure, demographic factors, and health status. We discuss implications of these findings on the participation of low-income families in public sector programs.     

Black/White Differences in Health Status and Mortality Among the Elderly

Grade of membership (GOM) representations are used to characterize and compare the health status of a very heterogeneous sample of blacks and whites in an elderly cohort of 2,806 noninstitutionalized men and women living in New Haven, Connecticut. They were interviewed in 1982 as part of the Established Populations for the Epidemiologic Study of the Elderly (EPESE). Ideal profiles based on functional disabilities, chronic diseases, and selected biomedical and behavioral risk factors are constructed empirically. Each individual in the sample is represented by a set of GOM scores, interpreted as degrees of similarity of his or her health record to each of the profiles. Four profiles emerge from GOM analyses: healthy elderly, elderly with cognitive impairment, elderly with impairment in mobility function and physical performance and with selected chronic conditions, and elderly with major limitations in activities of daily living and multiple chronic conditions. Although elderly blacks and whites generally have similar configurations of profiles, there are important differences, especially when chronic conditions are related to specific types of functional impairments. Questions about and claims for black/white mortality crossovers at older ages, usually addressed with aggregate data, are examined conditional on GOM scores that correspond to diverse combinations of disabilities (or lack thereof) together with housing characteristics of cohort members (e.g., whether they live in public housing for the elderly or in owned or rented housing in the community).     

Inference in model-based cluster analysis

A new approach to cluster analysis has been introduced based on parsimonious geometric modelling of the within-group covariance matrices in a mixture of multivariate normal distributions, using hierarchical agglomeration and iterative relocation. It works well and is widely used via the MCLUST software available in S-PLUS and StatLib. However, it has several limitations: there is no assessment of the uncertainty about the classification, the partition can be suboptimal, parameter estimates are biased, the shape matrix has to be specified by the user, prior group probabilities are assumed to be equal, the method for choosing the number of groups is based on a crude approximation, and no formal way of choosing between the various possible models is included. Here, we propose a new approach which overcomes all these difficulties. It consists of exact Bayesian inference via Gibbs sampling, and the calculation of Bayes factors (for choosing the model and the number of groups) from the output using the Laplace–Metropolis estimator. It works well in several real and simulated examples.