21,437 research outputs found

    Induced matter: Curved N-manifolds encapsulated in Riemann-flat N+1 dimensional space

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    Liko and Wesson have recently introduced a new 5-dimensional induced matter solution of the Einstein equations, a negative curvature Robertson-Walker space embedded in a Riemann flat 5-dimensional manifold. We show that this solution is a special case of a more general theorem prescribing the structure of certain N+1-dimensional Riemann flat spaces which are all solutions of the Einstein equations. These solutions encapsulate N-dimensional curved manifolds. Such spaces are said to "induce matter" in the sub-manifolds by virtue of their geometric structure alone. We prove that the N-manifold can be any maximally symmetric space.Comment: 3 page

    A comparison of an ATPase from the archaebacterium Halobacterium saccharovorum with the F1 moiety from the Escherichia coli ATP Synthase

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    A purified ATPase associated with membranes from Halobacterium saccharovorum was compared with the F sub 1 moiety from the Escherichia coli ATP Synthase. The halobacterial enzyme was composed of two major (I and II) and two minor subunits (III and IV), whose molecular masses were 87 kDa, 60 kDa, 29 kDa, and 20 kDa, respectively. The isoelectric points of these subunits ranged from 4.1 to 4.8, which in the case of the subunits I and II was consistent with the presence of an excess of acidic amino acids (20 to 22 Mol percent). Peptide mapping of sodium dodecylsulfate-denatured subunits I and II showed no relationship between the primary structures of the individual halobacterial subunits or similarities to the subunits of the F sub 1 ATPase (EC 3.6.1.34) from E. coli. Trypsin inactivation of the halobacterial ATPase was accompanied by the partial degradation of the major subunits. This observation, taken in conjunction with molecular masses of the subunits and the native enzyme, was consistent with the previously proposed stoichiometry of 2:2:1:1. These results suggest that H. saccharovorum, and possibly, Halobacteria in general, possess an ATPase which is unlike the ubiquitous F sub o F sub 1 - ATP Synthase

    A Theory of Dual Labor Markets with Application to Industrial Policy, Discrimination and Keynesian Unemployment

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    This paper develops a model of dual labor markets based on employers' need to motivate workers. In order to elicit effort from their workers, employers may find it optimal to pay more than the going wage. This changes fundamentally the character of labor markets. The modelis applied to a wide range of labormarket phenomena. It provides a coherent framework for understanding the claims of industrial policy advocates. It also can provide the basis for a theory of occupational segregation and discrimination which will not be eroded by market forces. Finally, the model provides the basis for a theory of involuntary unemployment.

    The Taxation of Risky Assets

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    This paper reconsiders the effects of taxation on risky assets, recognizing the importance of variations in asset prices. We show that earlier analyses which assumed that depreciation rates are constant and that the future price of capital goods is known with certainty are very misleading, as guides to the effects of corporate taxes. We then examine the concept of economic depreciation in a risky environment, and show that depreciation allowances, if set ex-ante, should be adjusted to take account of future asset price risk. Some empirical calculations suggest that these adjustments are large, and have important implications for the burdens of, and non-neutralities in, the corporate income tax.

    Admissible predictive density estimation

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    Let X∣μ∼Np(μ,vxI)X|\mu\sim N_p(\mu,v_xI) and Y∣μ∼Np(μ,vyI)Y|\mu\sim N_p(\mu,v_yI) be independent pp-dimensional multivariate normal vectors with common unknown mean μ\mu. Based on observing X=xX=x, we consider the problem of estimating the true predictive density p(y∣μ)p(y|\mu) of YY under expected Kullback--Leibler loss. Our focus here is the characterization of admissible procedures for this problem. We show that the class of all generalized Bayes rules is a complete class, and that the easily interpretable conditions of Brown and Hwang [Statistical Decision Theory and Related Topics (1982) III 205--230] are sufficient for a formal Bayes rule to be admissible.Comment: Published in at http://dx.doi.org/10.1214/07-AOS506 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Out-of-plane fluctuation conductivity of layered superconductors in strong electric fields

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    The non-Ohmic effect of a high electric field on the out-of-plane magneto-conductivity of a layered superconductor near the superconducting transition is studied in the frame of the Langevin approach to the time-dependent Ginzburg-Landau equation. The transverse fluctuation conductivity is computed in the self-consistent Hartree approximation for an arbitrarily strong electric field and a magnetic field perpendicular to the layers. Our results indicate that high electric fields can be effectively used to suppress the out-of-plane fluctuation conductivity in high-temperature superconductors and a significant broadening of the transition induced by a strong electric field is predicted. Extensions of the results are provided for the case when the electric field is applied at an arbitrary angle with respect to the layers, as well as for the three-dimensional anisotropic regime of a strong interlayer coupling.Comment: to be published in Phys. Rev.
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