22,350 research outputs found

    Design, develop and fabricate a feasibility model of a ferrimagnetic memory using an optical accession system for read write functions Final report

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    Design, development, and fabrication of feasibility model of magneto-optic memory with gadolinium iron garnet platelet

    Trade reforms and wage inequality in Colombia

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    We investigate the effects of the drastic tariff reductions of the 1980s and 1990s in Colombia on the wage distribution. We identify three main channels through which the wage distribution was affected: increasing returns to college education, changes in industry wages that hurt sectors with initially lower wages and a higher fraction of unskilled workers, and shifts of the labor force towards the informal sector that typically pays lower wages and offers no benefits. Our results suggest that trade policy played a role in each of the above cases. The increase in the skill premium was primarily driven by skilled-biased technological change; however, our evidence suggests, that this change may have been in part motivated by the tariff reductions and the increased foreign competition to which the trade reform exposed domestic producers. With respect to industry wages, we find that wage premiums decreased by more in sectors that experienced larger tariff cuts. Finally, we find some evidence that the increase in the size of the informal sector is related to increased foreign competition – sectors with larger tariff cuts and more trade exposure, as measured by the size their imports, experience a greater increase in informality, though this effect is concentrated in the years prior to the labor market reform. Nevertheless, increasing returns to education, and changes in industry premiums and informality alone cannot fully explain the increase in wage inequality we observe over this period. This suggests that overall the effect of the trade reforms on the wage distribution may have been small

    Real fluid properties of normal and parahydrogen

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    Computer program calculates the real fluid properties of normal or parahydrogen using a library of single function calls without initial estimates. Accurate transport and thermodynamic properties of molecular hydrogen are needed for advanced propulsion systems

    Exact Nonperturbative Unitary Amplitudes for 1->N Transitions

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    I present an extension to arbitrary N of a previously proposed field theoretic model, in which unitary amplitudes for 1−>81->8 processes were obtained. The Born amplitude in this extension has the behavior A(1−>N)tree = gN−1 N!A(1->N)^{tree}\ =\ g^{N-1}\ N! expected in a bosonic field theory. Unitarity is violated when ∣A(1−>N)∣>1|A(1->N)|>1, or when N>Ncrit≃e/g.N>\N_crit\simeq e/g. Numerical solutions of the coupled Schr\"odinger equations shows that for weak coupling and a large range of N>\ncrit, the exact unitary amplitude is reasonably fit by a factorized expression |A(1->N)| \sim (0.73 /N) \cdot \exp{(-0.025/\g2)}. The very small size of the coefficient 1/\g2 , indicative of a very weak exponential suppression, is not in accord with standard discussions based on saddle point analysis, which give a coefficient ∌1. \sim 1.\ The weak dependence on NN could have experimental implications in theories where the exponential suppression is weak (as in this model). Non-perturbative contributions to few-point correlation functions in this theory would arise at order $K\ \simeq\ \left((0.05/\g2)+ 2\ ln{N}\right)/ \ ln{(1/\g2)}inanexpansioninpowersof in an expansion in powers of \g2.$Comment: 11 pages, 3 figures (not included

    Solutions of Penrose's Equation

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    The computational use of Killing potentials which satisfy Penrose's equation is discussed. Penrose's equation is presented as a conformal Killing-Yano equation and the class of possible solutions is analyzed. It is shown that solutions exist in spacetimes of Petrov type O, D or N. In the particular case of the Kerr background, it is shown that there can be no Killing potential for the axial Killing vector.Comment: To appear in J. Math. Phy

    Weyl-type Fields with Geodesic Lines of Force

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    The static electrogravitational equations are studied and it is shown that an aligned type D metric which has a Weyl-type relationship between the gravitational and electric potential has shearfree geodesic lines of force. All such fields are then found and turn out to be the fields of a charged sphere, charged infinite rod and charged infinite plate. A further solution is also found with shearing geodesic lines of force. This new solution can have m>∣e∣m>|e| or m<∣e∣m<|e|, but cannot be in the Majumdar-Papapetrou class (in which m=∣e∣m = |e|). It is algebraically general and has flat equipotential surfaces.Comment: 13 pages, RevTe
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