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Humanity has just crossed a major landmark in its history with the majority of people now living in cities. Cities have long been known to be society's predominant engine of innovation and wealth creation, yet they are also its main source of crime, pollution, and disease. The inexorable trend toward urbanization worldwide presents an urgent challenge for(More)
With urban population increasing dramatically worldwide, cities are playing an increasingly critical role in human societies and the sustainability of the planet. An obstacle to effective policy is the lack of meaningful urban metrics based on a quantitative understanding of cities. Typically, linear per capita indicators are used to characterize and rank(More)
Brain cancer cells invade early on surrounding parenchyma, which makes it impossible to surgically remove all tumor cells and thus significantly worsens the prognosis of the patient. Specific structural elements such as multicellular clusters have been seen in experimental settings to emerge within the invasive cell system and are believed to express the(More)
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(More)
Invention in the city: Increasing returns to patenting as a scaling function of metropolitan size Luis M.A. Bettencourt a, José Lobo b,1, Deborah Strumsky c,∗ a CCS-3 Computer and Computational Sciences, Los Alamos National Laboratory, MS B256, Los Alamos, NM 87545, United States b Global Institute of Sustainability, Arizona State University, P.O. Box(More)
While prior research has considered the desirability and implications of employee mobility, less research has considered factors affecting the ease of mobility. This paper explores a legal constraint on mobility —employee noncompete agreements—by exploiting Michigan's apparently-inadvertent 1985 reversal of its enforcement policy as a natural experiment.(More)
Invention has been commonly conceptualized as a search over a space of combinatorial possibilities. Despite the existence of a rich literature, spanning a variety of disciplines, elaborating on the recombinant nature of invention, we lack a formal and quantitative characterization of the combinatorial process underpinning inventive activity. Here, we use US(More)
Urban areas consume more than 66% of the world's energy and generate more than 70% of global greenhouse gas emissions. With the world's population expected to reach 10 billion by 2100, nearly 90% of whom will live in urban areas, a critical question for planetary sustainability is how the size of cities affects energy use and carbon dioxide (CO2) emissions.(More)
Over the last few decades, in disciplines as diverse as economics, geography and complex systems, a perspective has arisen proposing that many properties of cities are quantitatively predictable due to agglomeration or scaling effects. Using new harmonized definitions for functional urban areas, we examine to what extent these ideas apply to European(More)