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We present a joint study of the U.S. structural transformation (the decline of agriculture as the dominating sector) and regional convergence (of southern to northern average wages). We find empirically that most of the regional convergence is attributable to the structural transformation: the nationwide convergence of agricultural wages to nonagricultural(More)
We provide a new and more complete analysis of the origins of the Dust Bowl of the 1930s, one of the most severe environmental crises in North America in the twentieth century. Severe drought and wind erosion hit the Great Plains in 1930 and lasted through 1940. There were similar droughts in the 1950s and 1970s, but no comparable level of wind erosion. We(More)
This paper is preliminary and may not be cited without the permission of the authors. We owe special thanks to Roy Bainer who participated in many of the processes that we analyze in the paper. We would like to acknowledge the valuable comments and help from Abstract This paper examines the impact and diffusion of the gasoline tractor in American(More)
The purpose of our study is to trace in vivo and during the perinatal period, the brain maturation process with exhaustive measures of the T2 relaxation time values. We also compared regional myelination progress with variations of the relaxation time values and of brain signal. T2 relaxation times were measured in 7 healthy premature newborns at the(More)
In this paper, we present a new automatic segmentation method for magnetic resonance images. The aim of this seg-mentation is to divide the brain into homogeneous regions and to detect the presence of tumors. Our method is divided into two parts. First, we make a pre-segmentation to extract the brain from the head. Then, a second segmentation is done inside(More)
Triplets composed of superconducting quadrupoles have been built and installed as .. the final focusing element for the high-energy positron and electron beams of the SLAC Linear Collider. Special features include independent alignment to lOO-micron tolerance inside a common cryostat; non-magnetic materials to allow operation inside the detector's solenoid(More)
I claim that China during the Song Dynasty (960 – 1279 AD) (Song China hereafter) experienced the onset of an Economic Revolution, preceding England's by nearly a millennium. The concept of Economic Revolution is defined to include two types – one Premodern (non-science based) with a low growth rate of per capita product and one Modern (science-based) with(More)
a r t i c l e i n f o a b s t r a c t This paper tests a key theoretical prediction of public finance, that local redistribution induces sorting of the population so that less productive individuals are located in communities with more redistribution. Specifically, I use a longitudinal data set to test whether and to what extent the intensive redistribution(More)