Spatial scale and measuring segregation: illustrated by the formation of Chicago’s ghetto

Few studies of residential segregation in cities have directly addressed the issue of spatial scale, apart from noting that the traditional indices of segregation tend to be larger when calculated for small rather than large spatial units. That observation however ignores Duncan et al.’s (Statistical geography: problems in analyzing areal data. Free Press, Glencoe, 1961) explication that any measure of segregation at a fine-grained scale necessarily incorporates, to an unknown extent, segregation at a larger scale within which the finer-grained units are nested. To avoid that problem, a multi-level modelling perspective is introduced that identifies the intensity of segregation at each scale net of its intensity at any larger scale included in the analysis. It is applied to an analysis of the emergence of Chicago’s Black ghetto over the twentieth century’s first three decades, using data at the ward and ED scales. It shows that across Chicago as a whole segregation was equally as intense at the two scales, with statistically significant increases in that intensity at both scales across the three decades. At the finer scale, however, segregation was much more intense across the EDs within those wards that formed the core of the emerging ghetto than it was in the remainder of the city.     

Using GIS and Dispersion Modelling Tools to Assess the Effect of the Environment on Health

A feasibility study in progress to integrate health and air quality information is presented. The methods of using integrated GIS and air quality dispersion modelling tools to assess the effect of the environment on health are discussed. The main aim is to model human personal exposure to air pollutants and compare the predictions to respiratory health data for asthmatics in a health telematics project. The MEDICATE project develops and tests the feasibility of using a health telematic system for asthmatics. Key to this is the determination of the real-time health (lung function) response to the ambient environment. For this, air quality information is related to respiratory measurements by modelling personal exposure through a GIS. The methods of integrating environmental modelling and assessment tools (GIS) in this case are examined. ESRI's ArcView is used to locate and compile environmental information about the patients' locations and lifestyles in the study areas (London and Barcelona). A dispersion modelling extension to ArcView, ADMS Urban, is used to interrogate the spatial environmental databases (e.g. emission inventories) to model air pollution concentrations. Patients' personal exposure is modelled by time-weighted estimates of their exposure to ambient air quality at each defined location. Lung function data can be compared on a time-wise basis with these air quality indicators to see if there is a relationship on an hourly, daily or lagged-day basis. The aim of this paper is to propose a methodology and discuss the integration and practicalities of using air quality assessment tools (inventories, dispersion modelling and a GIS) in assessing the impacts of the environment on human health.     

Geographic signatures of North American West Coast estuaries

West Coast estuaries are geologically young and composed of a variety of geomorphological types. These estuaries range from large fjords to shallow lagoons; from large to low freshwater flows. Natural hazards include E1 Niños, strong Pacific storms, and active tectonic activity. West Coast estuaries support a wide range of living resources: five salmon species, harvestable shellfish, waterfowl and marine birds, marine mammals, and a variety of algae and plants. Although populations of many of these living resources have declined (salmonids), others have increased (marine mammals). West Coast estuaries are also centers of commerce and increasingly large shipping traffic. The West Coast human population is rising faster than most other areas of the U.S. and Canada, and is distributed heavily in southern California, the San Francisco Bay area, around Puget Sound, and the Fraser River estuary. While water pollution is a problem in many of the urbanized estuaries, most estuaries do not suffer from poor water quality. Primary estuarine problems include habitat alterations, degradation, and loss; diverted freshwater flows; marine sediment contamination; and exotic species introductions. The growing West Coast economy and population are in part related to the quality of life, which is dependent on the use and enjoyment of abundant coastal natural resources.     

Geological and pedological aspects of an Early-Paleolithic site: Revadim,Central Coastal Plain,Israel

An Early Paleolithic site was recently discovered within a sequence of paleosols in the Revadim Quarry, central coastal plain of Israel. The section is composed of three superimposed soils in a continuous sequence, but separated by two unconformity surfaces. The uppermost paleosol is a modern Dark Brown Grumusol (Vertisol), the middle is a Quartzic Gray Brown Soil (Haploxeralf), and the lower is a Red Hamra (Rhodoxeralf). Normal magnetic polarity was detected in the two lower soils, indicating that they are younger than the Brunhes–Matuyama boundary (<780 ka). A human occupation bed, enriched in secondary carbonate nodules, forms the lower part of the Quartzic Gray Brown Soil and overlies the Red Hamra. The living floor is located on top of the unconformity surface, separating the Red Hamra from the overlying Quartzic Gray Brown Soil. Middle to Late Acheulian handaxes, choppers, cores, and flake tools, including tools made by the Levallois technique, and man-laid flint pebbles were excavated in the human occupation bed. In addition, two elephant tusks, an elephant pelvis, an elephant tooth (Palaeoloxodon antiquus), tusk splinters, and bones of equid, suid, cervid, bovid, felid, and rodents were also collected. Based on well-documented nearby boreholes and on regional correlation, it appears that the underlying dune sands, the parent materials from which the Red Hamra developed, were deposited probably during a phase of high-stand sea level of Isotope Stage 9. The Red Hamra developed simultaneously with the human occupation of the site, probably during a phase of low-stand sea-level of Isotope Stage 8, before some 300–245 ka. The overlying dune sands, the parent materials from which the Quartzic Gray Brown Soil developed, were deposited probably during a phase of high-stand sea level of Isotope Stage 7. The climate prevailing in the area during Stage 8, as well as during the human habitation, was moist, with a dense vegetation cover of grassland and probably scattered trees. A small lake of trapped fresh water at a junction of two small tributaries of the Soreq River drainage system near the area occupied was available to hominids and animals. © 1999 John Wiley & Sons, Inc.