W. Visscher

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Although exposure to ionizing radiation is a recognized risk factor for breast cancer, the potential hazard from low-dose, fractionated exposures during early breast development has not been thoroughly evaluated. Women with scoliosis represent a valuable population for studying this issue because they are exposed to multiple diagnostic x rays during(More)
BACKGROUND We examined levels of diabetes preventive care services and glycemic and lipid control among African Americans with diabetes in two North Carolina communities. METHODS Cross-sectional, population-based study of 625 African-American adults with diagnosed diabetes. Participants had a household interview to determine receipt of preventive care(More)
Project DIRECT (Diabetes Intervention Reaching and Educating Communities Together) is a multilevel community-based intervention project designed to address diabetes and its complications in an African-American community. This article presents results of the Project DIRECT pilot study and describes risk factors for diabetes, diabetes prevalence,(More)
OBJECTIVES The Dallas County study of a proposed national household seroprevalence survey was designed to assess the feasibility of conducting a national survey and to estimate the prevalence of human immunodeficiency virus (HIV) and hepatitis B virus infection for Dallas County. Risk behavior data were collected and correlated with HIV infection. METHODS(More)
Project DIRECT (Diabetes Interventions Reaching and Educating Communities Together) is the first comprehensive community diabetes demonstration project in the United States in an African-American community. This article describes its intervention components and evaluation design. The development and implementation of Project DIRECT has included the(More)
A business ecosystem is a network of suppliers and customers around a core technology, who depend on each other for their success and survival. In this paper we present a simple agent-based model of a business ecosystem. This includes a conceptualization of the model, a specification of the model and a small series of experiments to investigate the(More)
"Selected Papers of Freeman Dyson with Commentary," a collection of technical papers selected by Dyson, with commentary telling how they came to be written, published by the American Mathematical Society, 1996. " Recent Developments in High Energy Physics. " Notes taken from an unfinished manuscript of Professor Julian Schwinger, " On Gauge Invariance and(More)
In a retrospective cohort study of 1,409 persons diagnosed with scoliosis between 1927 and 1965 in Minneapolis and St. Paul, Minnesota, mailed questionnaires were obtained for 846 white women. Six hundred and eight (72%) of these women had ever been pregnant, and they reported a total of 1,733 pregnancies and 1,413 livebirths. Adverse outcomes among the(More)