AIDS NORTH AND SOUTH: DIFFUSION PATTERNS OF A GLOBAL EPIDEMIC AND A RESEARCH AGENDA FOR GEOGRAPHERS *

Apart from the tragic certainty of death which accompanies AIDS everywhere, the means of its transmission, the spatial patterns of its diffusion, and the groups at highest risk of infection vary considerably among world regions. This paper reviews the disease and its transmission, then proposes three models of AIDS diffusion to assess the implications of the epidemic on various regions. AIDS North, of North America and western Europe, is urban based and primarily confined to homosexuals and IV drug abusers. AIDS South, in central Africa and the Caribbean, is spreading from cities into rural regions and affects primarily heterosexuals. The third, an AIDS North/South hybrid, is postulated as a model of diffusion of the disease in other Third World regions. The final section addresses the potential contribution of geographic research to policy-makers in attempting to cope with the diffusion of AIDS and in curbing the epidemic's advance.     

SEARCHING METHODS FOR RAPID GRID INTERPOLATION*

A widely used method for grid interpretation from a set of discrete sample points is based on the inverse distanceweighted model. This method requires the identification of k-nearest sample points for each grid point, probably the most time-consuming portion of the grid interpolation process. Three searching methods for identifying the k-nearest sample points are discussed and compared. Two of these methods were consistenty faster without sacrificing accuracy than the brute-force searching method, and one method was from one to over 90 times faster than the brute-force searching method.     

INFORMATION SOURCES FOR NINETEENTH CENTURY MIDWESTERN MIGRATION*

A variety of sources provides different levels of information about the origins of nineteenth century migrants to the Midwest. The advantages and disadvantages of four of the most common records, the federal census, land office records, genealogical collections, and county histories/biographies/atlases, are examined. Characteristics considered are the specific types of data provided, extent of coverage, level of detail, statistical reliability, and accessibility. Examples of studies using each record type are cited.     

FARMLAND CONVERSION: NATIONAL LESSONS FOR IOWA*

Between 1967 and 1975, United States cropland declined 30.5 million acres, of which 8 million acres were prime farmland. The rising gross farm product continues to outweigh such losses owing to short-term adjustments such as irrigation, but longer-term measures to conserve farmland are widely urged. Even Iowa, where urban growth is modest, is incurring some loss of superior farmland. Experience in other states offers certain lessons to Iowa: discourage unnecessary municipal annexations; evaluate the impact of public investments on farmland; expand tax preferences for agriculture; and assist counties to improve their land planning and regulatory efforts.     

REGRESSION ON MULTIVARIATE IMAGES:PRINCIPAL COMPONENT REGRESSION FOR MODELING,PREDICTION AND VISUAL DIAGNOSTIC TOOLS

Regression between two blocks(usually called‘dependent’or Y and‘independent’or X)of data is a veryimportant scientific and data-analytical tool.Regression on multivariate images is possible and constitutesa meaningful addition to existing univariate and multivariate techniques of image analysis.The regressioncan be used as a modeling tool or for prediction.The form of the regression equation chosen is dependentupon problem specification and information at hand.This paper describes the use of principal componentregression(PCR).Both model building and prediction are presented for continuous Y-variables.The finalgoal is to supply new image material that can be used for visual inspection on a screen.Also,visual toolsfor diagnosis of model and prediction are provided,often based on derived image material.Examplesof modeling and prediction are given for six channels in a seven-channel satellite image     

HUMAN MODIFICATION OF KOREAN LANDFORMS FOR GEOMANTIC PURPOSES*

The geomantic idea of chosan pibo is a particular way of remedying the inadequacies of a geomantic landscape by building small mounds of earth or stones and has been a significant motivation for modifying the environment in Korea. This idea is a part of ancient Chinese geomancy, or feng shui, for determining auspicious sites. Historically, three principal geomantic means have been used to compensate for shortcomings at an auspicious site: building religious structures, such as temples; creating hills, planting trees, or changing directions of watercourses; or making other symbolic gestures, such as naming objects and places. In this article I concentrate on the second, modifying landforms to compensate for the geomantic shortcomings of a place. The quasi‐religious zeal shown by feng shui practitioners in Korea to improve the local geomantic landscape is worthy of comparing and contrasting with the European Christian idea, held by medieval monastic monks, that humanity is a partner of God in improving the environment.     

BITNET: A TOOL FOR COMMUNICATIONS AMONG GEOGRAPHERS*

BITNET is a telecommunications network for higher education. The network's general characteristics, services, the availability of BITNET to academic geographers, and their use of the system are examined. Although more than 80% of geography faculty in the United States and Canada are at BITNET-supported institutions, a survey of AAG Specialty Group chairs suggests that geographers' actual use of BITNET is relatively low.     

THE EXPANSION METHOD: IMPLICATIONS FOR GEOGRAPHIC RESEARCH*

Geographic phenomena and our models of them are closely linked to the spatial-temporal contexts in which they are observed. The expansion method is a procedure that incorporates contextual effects into mathematical models. More importantly, it is the basis for a movement by some geographers away from the classical spatial science paradigm. The evolving paradigm associated with the expansion method represents a reformulation of the way in which geographers think about and use models, and is consistent with a more realistic perspective on the nature of geographic inquiry.     

SELLERS AND NONSELLERS OF LAND FOR NEW RURAL HOUSING*

Landowners can choose either to sell or to hold their land in areas with active rural land markets. Sellers and nonsellers are both important because their decisions shape patterns of land use. Analysis of mail survey data from 286 landowners in the Rochester, MN SMSA isolates four characteristics that distinguish sellers from nonsellers: occupation, size of landholding, recent acquisition of land, and interest in selling land. Nonsellers are often farmers with a large landholding and no interest in selling. More information is needed about their non-economic motives for holding land.     

METHOD FOR RECOGNIZING LOCAL BEDROCK INFLUENCE ON DRIFT PLAINS*

Analysis of topographic and bedrock surface data from 41 sites 23.3 km² (9 m²) within Midwestern areas glaciated during the Late Wisconsinan identifies an average drift thickness-maximum bedrock relief transition equation for the presence or absence of bedrock surface influences on topographic detail. For sites with average drift thicknesses between 15 and 35 m, the transition occurs when average drift thicknesses exceed 0.5 maximum bedrock relief + 10 m. This equation may provide a practical tool in searching for buried bedrock valleys.     

SPATIAL PATTERNS OF SUPPORT FOR A NUCLEAR WEAPONS FREEZE*

Support for a Freeze on nuclear weapons is greatest in the East with pockets of support in the Middle West and Pacific Coast States. Factors influencing the spatial pattern are Walker's innovativeness rankings, the number of peace/Freeze activist groups and the pattern of defense employment.