122,757 research outputs found

    Legal Rules and Bankruptcy Rates: Historical Evidence from the States

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    Since the early twentieth century, observers have attributed the wide variation in state bankruptcy rates to variation in state legal rules such as garnishment and bankruptcy exemptions. Recent econometric analyses, however, conclude that legal rules do not matter. We explore the impact of legal rules on bankruptcy rates using a new technique—fixed effects vector decomposition—to exploit historical variation in legal rules. The technique allows us to estimate the impact of timeinvariant legal rules in a fixed effects framework. We find that the variation in state legal rules explains much of the variation in state wage earner bankruptcy rates for 1926 to 1932.Bankruptcy, fixed effects vector decomposition, law and economics

    A Computationally Efficient Limited Memory CMA-ES for Large Scale Optimization

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    We propose a computationally efficient limited memory Covariance Matrix Adaptation Evolution Strategy for large scale optimization, which we call the LM-CMA-ES. The LM-CMA-ES is a stochastic, derivative-free algorithm for numerical optimization of non-linear, non-convex optimization problems in continuous domain. Inspired by the limited memory BFGS method of Liu and Nocedal (1989), the LM-CMA-ES samples candidate solutions according to a covariance matrix reproduced from mm direction vectors selected during the optimization process. The decomposition of the covariance matrix into Cholesky factors allows to reduce the time and memory complexity of the sampling to O(mn)O(mn), where nn is the number of decision variables. When nn is large (e.g., nn > 1000), even relatively small values of mm (e.g., m=20,30m=20,30) are sufficient to efficiently solve fully non-separable problems and to reduce the overall run-time.Comment: Genetic and Evolutionary Computation Conference (GECCO'2014) (2014

    Temperature dependent deviations from ideal quantization of plateau conductances in GaAs quantum point contacts

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    We present detailed experimental studies of the temperature dependence of the plateau conductance of GaAs quantum point contacts in the temperature range from 0.3 K to 10 K. Due to a strong lateral confinement produced by a shallow-etching technique we are able to observe the following unexpected feature: a linear temperature dependence of the measured mid-plateau conductance. We discuss an interpretation in terms of a temperature dependent, intrinsic series resistance, due to non-ballistic effects in the 2D-1D transition region. These results have been reproduced in several samples from different GaAs/GaAlAs heterostructures and observed in different experimental set-ups.Comment: 7 pages, 6 figures; to appear in proceedings of ICPS 2002, Edinburg

    Comparison of Solar and Other Influences on Long-term Climate

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    Examples are shown of climate variability, and unforced climate fluctuations are discussed, as evidenced in both model simulations and observations. Then the author compares different global climate forcings, a comparison which by itself has significant implications. Finally, the author discusses a new climate simulation for the 1980s and 1990s which incorporates the principal known global climate forcings. The results indicate a likelihood of rapid global warming in the early 1990s

    Suitability of commercially available laboratory cryogenic refrigerators to support shipboard electro-optical systems in the 10 - 77 Kelvin region

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    The primary development of cryogenically cooled infrared systems was accomplished by FLIR systems designed for airborne, passive night vision. Essential to the development of these FLIR systems was a family of closed cycle refrigerators which had to meet a limited envelope requirement, utilize a nonlubricated compressor module, and be light in weight. Closed cycle refrigerators accomplished the same cooling function, they use modified oil lubricated reciprocating compressors which are limited in their axis of orientation to an angle of approximately 15-20 degrees maximum from horizon

    Relativistic, model-independent, multichannel 222\to2 transition amplitudes in a finite volume

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    We derive formalism for determining 2+J2\textbf{2} + \mathcal J \to \textbf{2} infinite-volume transition amplitudes from finite-volume matrix elements. Specifically, we present a relativistic, model-independent relation between finite-volume matrix elements of external currents and the physically observable infinite-volume matrix elements involving two-particle asymptotic states. The result presented holds for states composed of two scalar bosons. These can be identical or non-identical and, in the latter case, can be either degenerate or non-degenerate. We further accommodate any number of strongly-coupled two-scalar channels. This formalism will, for example, allow future lattice QCD calculations of the ρ\rho-meson form factor, in which the unstable nature of the ρ\rho is rigorously accommodated.Comment: 35 pages, 11 figure
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