56,608 research outputs found

    Firm and industry effects in accounting versus economic profit data

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    This article presents estimates of firm and industry fixed-effects on profit rates for large US corporations, using both Economic Value Added (EVA), the popular measure of profits produced by Stern Stewart and Company, as well as simple (unadjusted) accounting measures as the dependent variable. We find that the improvement in explanatory power of the fixed-effect model is substantially greater when using EVA than has been documented with alternative measures

    The Persistence of Accounting versus Economic Profit

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    Drawing on Schumpeterian theory, this article presents estimates of a first-order autoregressive model of profit persistence for large US firms, using Economic Value Added (EVA), the popular measure of profits produced by Stern Stewart and Company, and simple (unadjusted) accounting measures from the Compustat database. We hypothesize about the differences we should expect to find between these two sets of estimates, and also provide a fresh normative assessment of the dynamic competitiveness of the US economy

    Relaxed Three-Algebras: Their Matrix Representations and Implications for Multi M2-brane Theory

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    We argue that one can relax the requirements of the non-associative three-algebras recently used in constructing D=3, N=8 superconformal field theories, and introduce the notion of ``relaxed three-algebras''. We present a specific realization of the relaxed three-algebras in terms of classical Lie algebras with a matrix representation, endowed with a non-associative four-bracket structure which is prescribed to replace the three-brackets of the three-algebras. We show that both the so(4)-based solutions as well as the cases with non-positive definite metric find a uniform description in our setting. We discuss the implications of our four-bracket representation for the D=3, N=8 and multi M2-brane theory and show that our setup can shed light on the problem of negative kinetic energy degrees of freedom of the Lorentzian case.Comment: 31 pages, no figure

    Directive emission of red conjugated polymer embedded within zero index metamaterials

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    Abstract: We numerically demonstrate an impedance-matched multilayer stacked fishnet metamaterial that has zero index with flat high transmittance from 600nm to 620nm. The effective refractive index

    Polymer packaging and ejection in viral capsids: shape matters

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    We use a mesoscale simulation approach to explore the impact of different capsid geometries on the packaging and ejection dynamics of polymers of different flexibility. We find that both packing and ejection times are faster for flexible polymers. For such polymers a sphere packs more quickly and ejects more slowly than an ellipsoid. For semiflexible polymers, however, the case relevant to DNA, a sphere both packs and ejects more easily. We interpret our results by considering both the thermodynamics and the relaxational dynamics of the polymers. The predictions could be tested with bio-mimetic experiments with synthetic polymers inside artificial vesicles. Our results suggest that phages may have evolved to be roughly spherical in shape to optimise the speed of genome ejection, which is the first stage in infection.Comment: 4 pages, 4 figure

    The measured compositions of Uranus and Neptune from their formation on the CO iceline

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    The formation mechanisms of the ice giants Uranus and Neptune, and the origin of their elemental and isotopic compositions, have long been debated. The density of solids in the outer protosolar nebula is too low to explain their formation, and spectroscopic observations show that both planets are highly enriched in carbon, very poor in nitrogen, and the ices from which they originally formed might had deuterium-to-hydrogen ratios lower than the predicted cometary value, unexplained properties observed in no other planets. Here we show that all these properties can be explained naturally if Uranus and Neptune both formed at the carbon monoxide iceline. Due to the diffusive redistribution of vapors, this outer region of the protosolar nebula intrinsically has enough surface density to form both planets from carbon-rich solids but nitrogen-depleted gas, in abundances consistent with their observed values. Water rich interiors originating mostly from transformed CO ices reconcile the D/H value of Uranus and Neptune's building blocks with the cometary value. Finally, Our scenario generalizes a well known hypothesis that Jupiter formed on an iceline (water snowline) for the two ice giants, and might be a first step towards generalizing this mechanism for other giant planets.Comment: The Astrophysical Journal (in press), 8 pages, 5 figure

    Fermions in non-relativistic AdS/CFT correspondence

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    We extend the non-relativistic AdS/CFT correspondence to the fermionic fields. In particular we study the two point function of a fermionic operator in non-relativistic CFTs by making use of a massive fermion propagating in geometries with Schrodinger group isometry. Although the boundary of the geometries with Schrodinger group isometry differ from that in AdS geometries where the dictionary of AdS/CFT is established, using the general procedure of AdS/CFT correspondence, we see that the resultant two point function has the expected form for fermionic operators in non-relativistic CFTs, though a non-trivial regularization may be needed.Comment: 12 pages,Latex file; V2: typos corrected, refs adde

    The persistence of accounting versus economic profit

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    Drawing on Schumpeterian theory, this article presents estimates of a first-order autoregressive model of profit persistence for large US firms, using Economic Value Added (EVA), the popular measure of profits produced by Stern Stewart and Company, and simple (unadjusted) accounting measures from the Compustat database. We hypothesize about the differences we should expect to find between these two sets of estimates, and also provide a fresh normative assessment of the dynamic competitiveness of the US economy.dynamic competition efficiency persistence

    Submm-bright QSOs at z~2: signposts of co-evolution at high z

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    We have assembled a sample of 5 X-ray and submm-luminous z~2 QSOs which are therefore both growing their central black holes through accretion and forming stars copiously at a critical epoch. Hence, they are good laboratories to investigate the co-evolution of star formation and AGN. We have performed a preliminary analysis of the AGN and SF contributions to their UV-to-FIR SEDs, fitting them with simple direct (disk), reprocessed (torus) and star formation components. All three are required by the data and hence we confirm that these objects are undergoing strong star formation in their host galaxies at rates 500-2000 Msun/y. Estimates of their covering factors are between about 30 and 90%. In the future, we will assess the dependence of these results on the particular models used for the components and relate their observed properties to the intrinsice of the central engine and the SF material, as well as their relevance for AGN-galaxy coevolution.Comment: 6 pages, 2 figures, contributed talk to "Nuclei of Seyfert galaxies and QSOs - Central engine & conditions of star formation" November 6-8, 2012. MPIfR, Bonn, Germany. Po
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