We investigate the relationship between patenting activity and the size of metropolitan areas in the United States over the last two decades (1980-2001). We find a clear superlinear effect, whereby patents are granted disproportionately in larger urban centers, thus showing increasing returns in inventing activity with respect to population size. We characterize this relation quantitatively as ...

introduction there is a wide transformation achieving to sustainable development terms. sustainable development is not a new concept but it shows the process of transformation of social, economic and natural systems. at the end of 1987s a new paradigm, called sustainability, concluded that scientific evidence demonstrated rapid destruction of air, water, species of flora and fauna, deserts, for...

This paper proposes four metrics to measure sprawl in metropolitan regions as marginal changes in land use over time. The metrics (change in urban housing unit density, marginal land consumption per new urban household, housing unit density in newly urbanized areas and percent of new housing units located in previously developed areas) are computed for all 329 metropolitan areas in the continen...

U.S. metropolitan neighborhoods have become increasingly segregated by income over the past thirty years. The metropolitan areas with the largest rises in income segregation include a number of distressed cities in industrial decline, as well as a subset of rapidly growing metropolitan areas. I propose a simple model based on the notion that rising income inequality creates market pressure (or ...

BACKGROUND Few studies of colorectal cancer incidence by rural, suburban, and metropolitan residence have been published. METHODS The authors examined colorectal cancer incidence among men and women in U.S. counties classified as rural, suburban, and metropolitan for the period 1998-2001. They examined rural/suburban/metropolitan differences in incidence by age, race, Hispanic ethnicity, stag...