Spatial Diffusion of the HIV/AIDS Epidemic: Modeling Implications and Case Study of AIDS Incidence in Ohio

This paper extends a compartmental epidemiological model for HIV transmission and AIDS incidence to include hierarchical and expansion spatial diffusion. An implication of the resultant model is that hierarchical diffusion causes the large infection growth rates of densely populated areas at the top of the central places hierarchy to “chain” down and dominate small local growth rates during the exponential-growth phase of the epidemic. Also, hierarchical diffusion causes a high transient growth rate in the first few years of a local epidemic. The spatial compartmental model fits observed AIDS incidence spatial diffusion patterns in Ohio reasonably well.     

Modeling Interaction in a System of Markets

This paper develops a nested family of market interaction models for the general case of spatial or aspatial goods. Market structure effects are identified in the form of intraregional and extraregional competition. The competing destinations and competing central place models are shown to be special cases of the general modeling framework. An empirical example, using survey data collected from Chicago-area Management and Public Relations (SIC 874) firms, illustrates how the family of models may be used to identify market structure.     

The SEM and uneven development: Automotive production and the ‘older’ peripheral regions of the UK

This paper examines the impact of the creation of the Single European Market (SEM) by exploring the restructuring of the automotive production sector in Europe and its effect upon the older industrial regions of the UK. The paper is divided into four sections. Firstly, the importance of automotive production as a key sector in understanding the true impact of restructuring for the SEM is outlined. Secondly, the directions and outcomes of restructuring in the sector are detailed. Thirdly, the specific impact of these changes on automotive production and the older peripheral regions of the UK is considered. Finally, some conclusions and future directions for policy are discussed in relation to the true shape and form of ‘the new Europe’. The paper argues that the SEM will reinforce and deepen the pervasive and divergent effects of industrial restructuring within its boundaries due to economic relations from without.     

Environmental limitations on prehistoric pastoralism in Africa

In several areas of Africa, pastoralism that existed prehistorically no longer survives today. Two such areas, the Southwestern Cape of South Africa and the Sahara, are discussed here, outlining methodologies for reconstruction of adaptive strategies on the basis of environmental parameters that constrained the pastoral economies.

---

Résumé En plusieurs régions d'Afrique, le pastoralisme qui existait en temps préhistorique a maintenant disparu. L'article discute de deux de ces régions, le cap sud-ouest de l'Afrique du Sud et le Sahara, donnant un aperçu des méthodologies qui visent la reconstruction des stratégies adaptatrices en se fondant sur les paramètres écologiques qui ont contraint les économies pastorales.