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Let D d,k denote the discriminant variety of degree d polynomials in one variable with at least one of its roots being of multiplicity ≥ k. We prove that the tangent cones to D d,k span D d,k−1 thus, revealing an extreme ruled nature of these varieties. The combinatorics of the web of affine tangent spaces to D d,k in D d,k−1 is directly linked to the root(More)
We examine the long-term links between state capacity and economic performance. Our database is novel and spans 11 countries and 4 centuries in Europe, the birthplace of modern economic growth. A dynamic simultaneous equation panel model indicates that the performance effects of states with modern extractive and productive capabilities are significant,(More)
This paper examines the relationships between warfare, taxation, and politic institutions in historical perspective. We focus on nineteenth-century Italy from the end of the Napoleonic era in 1815 to political unification in 1861. The institutional variety at the regional level makes the Italian peninsula a unique testing ground for comparative work. Using(More)
OBJECTIVE To assess the outcome and risk factors for failure of pneumatic retinopexy (PR) in eyes with primary rhegmatogenous retinal detachment (RRD). METHODS Data of patients who underwent PR for the repair of primary RRD, from January 1, 2000, through June 30, 2011, were retrieved from medical records and retrospectively analyzed. Patients with a(More)
We present new evidence about the long-term links between state capacity and economic performance. Our database is novel and spans 11 countries and 4 centuries in Europe, the birthplace of modern economic growth. Using standard panel data methods, we find that the performance impacts of states with modern extractive and productive capabilities are(More)