128,532 research outputs found

    Do Some Stakeholders in Publicly Traded Firms Benefit at the Expense of Others as a Result of Corporate Inversions?

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    This report examines corporate inversions to determine whether this practice benefits the majority of stakeholders or merely a select few. A sample of firms previously incorporated in the United States that have since undergone inversions is examined to answer this question. Annual stock price returns, stock price volatility, and earnings per share changes from the sample of inversion firms are the main sources of data examined. These results are compared to the S&P 500 and peer firms to determine whether the changes can be attributed to the inversions, or are merely a result of general economic conditions. Supporting topics addressed in this paper include an overview of legislation related to inversions and suggestions to mitigate the negative consequences of inversions. This study shows that there are no observable benefits to shareholder wealth arising from corporate inversions. While there were changes in the data from pre to post inversion, they were not unique to the inversion firms as the same changes were observed in the peer firms. However, the study showed that there is a fundamental difference between inversion firms when compared to the S&P 500

    The stability of late-type stars close to the Eddington limit

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    Super-Eddington luminosities in hydrostatic model atmospheres manifest themselves by the presence of gas pressure inversions. Such inversions are not an artifact of the assumption of hydrostatic equilibrium but can also be present in hydrodynamical model atmospheres. Only for very large mass loss rates hardly realized in supergiants will the inversions be removed. Instabilities may, however, still be present in such inversions, which is investigated for both H-rich and H-deficient late-type supergiant model atmospheres. A local, non-adiabatic, linear stability analysis reveals that sound waves can be amplified due to the strong radiative forces. However, despite the super-Eddington luminosities, the efficiency of the radiative instabilities is fairly low compared to for early-type stars with growth rates of 105s110^{-5} s^{-1}.Comment: 11 pages; accepted for publication in Astronomy & Astrophysic

    On Quasi-inversions

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    Given a bounded domain DRnD \subset {\mathbb R}^n strictly starlike with respect to 0D,0 \in D\,, we define a quasi-inversion w.r.t. the boundary D.\partial D \,. We show that the quasi-inversion is bi-Lipschitz w.r.t. the chordal metric if and only if every "tangent line" of D\partial D is far away from the origin. Moreover, the bi-Lipschitz constant tends to 1,1, when D\partial D approaches the unit sphere in a suitable way. For the formulation of our results we use the concept of the α\alpha-tangent condition due to F. W. Gehring and J. V\"ais\"al\"a (Acta Math. 1965). This condition is shown to be equivalent to the bi-Lipschitz and quasiconformal extension property of what we call the polar parametrization of D\partial D. In addition, we show that the polar parametrization, which is a mapping of the unit sphere onto D,\partial D\,, is bi-Lipschitz if and only if DD satisfies the α\alpha-tangent condition.Comment: 22 pages; 5 figure

    Temporal evolution of the Evershed flow in sunspots. II. Physical properties and nature of Evershed clouds

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    Context: Evershed clouds (ECs) represent the most conspicuous variation of the Evershed flow in sunspot penumbrae. Aims: We determine the physical properties of ECs from high spatial and temporal resolution spectropolarimetric measurements. Methods: The Stokes profiles of four visible and three infrared spectral lines are subject to inversions based on simple one-component models as well as more sophisticated realizations of penumbral flux tubes embedded in a static ambient field (uncombed models). Results: According to the one-component inversions, the EC phenomenon can be understood as a perturbation of the magnetic and dynamic configuration of the penumbral filaments along which these structures move. The uncombed inversions, on the other hand, suggest that ECs are the result of enhancements in the visibility of penumbral flux tubes. We conjecture that the enhancements are caused by a perturbation of the thermodynamic properties of the tubes, rather than by changes in the vector magnetic field. The feasibility of this mechanism is investigated performing numerical experiments of thick penumbral tubes in mechanical equilibrium with a background field. Conclusions: While the one-component inversions confirm many of the properties indicated by a simple line parameter analysis (Paper I of this series), we tend to give more credit to the results of the uncombed inversions because they take into account, at least in an approximate manner, the fine structure of the penumbra.Comment: Accepted for publication in A&

    Multidimensional Matrix Inversions and Elliptic Hypergeometric Series on Root Systems

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    Multidimensional matrix inversions provide a powerful tool for studying multiple hypergeometric series. In order to extend this technique to elliptic hypergeometric series, we present three new multidimensional matrix inversions. As applications, we obtain a new ArA_r elliptic Jackson summation, as well as several quadratic, cubic and quartic summation formulas

    A Tonnetz Model for pentachords

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    This article deals with the construction of surfaces that are suitable for representing pentachords or 5-pitch segments that are in the same T/IT/I class. It is a generalization of the well known \"Ottingen-Riemann torus for triads of neo-Riemannian theories. Two pentachords are near if they differ by a particular set of contextual inversions and the whole contextual group of inversions produces a Tiling (Tessellation) by pentagons on the surfaces. A description of the surfaces as coverings of a particular Tiling is given in the twelve-tone enharmonic scale case.Comment: 27 pages, 12 figure
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