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It is late afternoon, and two figures are seen walking slowly along a path that leads through laurel, olives, and vines towards white Colonus, earth's loveliest, where the nightingales liquid notes most haunt the darkness of green glades. They are deep in conversation, yet move with steady, purposeful strides towards an inn that cools its crisp Demesticha in the flowing waters of a spring.

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. (EXCERPT)

We developed new equations to predict Oregon white oak (Quercus garryana Dougl. ex Hook.) development within ORGANON, a stand-development model that is widely used in the Pacific Northwest. Tree size, competitive status, crown ratio, and site productivity were statistically significant predictors of growth and mortality. Three scenarios were projected with the new equations, the previous ORGANON model, and the Forest Vegetation Simulator. Compared with the two other models, the new equations predicted greater diameter growth in oak woodland and a greater effect of conifer removal in a conifer-oak stand. The new equations, which are based on considerably more information than previous equations, should give forest managers greater confidence in the ability of ORGANON to estimate the impacts of silvicultural treatments on oaks.

Les cartes de préférences résidentielles et de surfaces d'information du Québec et de l'Ontario varient considérablement entre les enfants et les jeunes adultes des deux provinces. Elles reflètent une expérience différente de migration, d'éducation et de politique économique. D'importantes questions d'ordre méthodologique sont aussi soulevées concernent l'effet de barrière joué par la langue et la culture dans un tel contexte., Maps of residential desirability and information surfaces in Québec and Ontario vary consider-ably between children and young adults in the two provinces. Such differences reflect variations in migration, education and economic factors. Difficult methodological questions are raised concerning the measurement of cultural and linguistic barrier effects.

Some are called to looking at the world from the spatial perspective of the geographer. Distance powerfully structures many human spaces, and its effects are constantly revised by new technologies. For analytical purposes, both physical and human spaces may be transformed to produce conceptually simplified descriptions of apparently complex processes. Such spatio-temporal processes themselves are shaped by the structure of the underlying spaces. Examples range over behavioural, Shakespearian, air passenger, cross-country skiing and other spaces, and include the effects of spatial structure on the diffusion of influenza, HIV, and a virulent form of rabies. The epidemiological topics point to the educational task of helping others see the geography, as well as the more conventional history, in their own and specialized topics.

We sampled trees grown with and without competing vegetation control in an 11-year-old Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) plantation on a highly productive site in southwestern Washington to create diameter based allometric equations for estimating individual-tree bole, branch, foliar, and total aboveground biomass. We used these equations to estimate per-hectare aboveground biomass, nitrogen (N), and carbon (C) content, and compared these results to (1) estimates based on biomass equations published in other studies, and (2) estimates made using the mean-tree method rather than allometric equations. Component and total-tree biomass equations were not influenced by the presence of vegetation control, although per-hectare biomass, C, and N estimates were greater where vegetation control was applied. Our biomass estimates differed from estimates using previously published biomass equations by as much as 23 percent. When using the mean-tree biomass estimation approach, we found that incorporating a previously published biomass equation improved accuracy of the mean-tree diameter calculation.

Recent empirical research, and a simple stochastic modeling exercise, suggest that affluent suburban communities are at increased risk for the diffusion of HIV from present inner city epicenters, while the 'core group' construct of sexually transmitted disease theory suggests, somewhat counter-intuitively, that the hypercongregated and strongly self-interacting nature of affluent heterosexual elites in the U.S. places them at significant and increasing risk as well. In turn, a growing body of work strongly associates high HIV prevalence in minority urban populations with the processes of coupled physical and social disintegration which have produced the now-common and politically-generated 'hollowed out' pattern of U.S. cities. We conclude that a return to the principles of the Great Reform Movement, which first brought public health and public order to U.S. urban areas, is a necessary, but at present largely unrecognized, component to any successful national program to control AIDS in the United States, and particularly to stem the diffusion of HIV into heterosexual populations outside present diseases epicenters.

(1989). Geographic Dimensions of the AIDS Epidemic. The Professional Geographer: Vol. 41, No. 1, pp. 71-78.

(1970). Is Statistix Inferens the Geographical Name for A Wild Goose? Economic Geography: Vol. 46, PROCEEDINGS International Geographical Union Commission on Quantitative Methods, pp. 439-448.