242,044 research outputs found

    Scalar curvature in conformal geometry of Connes-Landi noncommutative manifolds

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    We first propose a conformal geometry for Connes-Landi noncommutative manifolds and study the associated scalar curvature. The new scalar curvature contains its Riemannian counterpart as the commutative limit. Similar to the results on noncommutative two tori, the quantum part of the curvature consists of actions of the modular derivation through two local curvature functions. Explicit expressions for those functions are obtained for all even dimensions (greater than two). In dimension four, the one variable function shows striking similarity to the analytic functions of the characteristic classes appeared in the Atiyah-Singer local index formula, namely, it is roughly a product of the jj-function (which defines the A^\hat A-class of a manifold) and an exponential function (which defines the Chern character of a bundle). By performing two different computations for the variation of the Einstein-Hilbert action, we obtain a deep internal relations between two local curvature functions. Straightforward verification for those relations gives a strong conceptual confirmation for the whole computational machinery we have developed so far, especially the Mathematica code hidden behind the paper.Comment: 44 pages, 11 figures, some minor updates from the previous versio

    Earnings target and the competing use of abnormal R&D and abnormal accruals of R&D intensive firms : a thesis presented in partial fulfilment of the requirements for the degree of Master of Management in Accountancy at Massey University

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    The purpose of this study is to examine the competing use of real earnings management and accruals management in certain specific circumstances of firms where both real earnings management and accruals management are costly and where firms can either use both or any of the two methods of earnings management to meet earnings targets. A recent study, Zang (2005), examines the competing use of real earnings management and accruals management. She finds that in a broad sample firms tend to use real earnings management before accruals management. This study overlooks the issue that in such a sample firms that are not R&D intensive would find R&D reductions less costly than accruals management. She also overlooks the point that the tendency to use different methods of earnings management depends on how far the earnings are from the earnings targets. I conduct an examination of the competing use of real earnings management and accruals management in a sample of R&D intensive firms. I use R&D intensive firms because R&D reduction can be costly for them as costs of future earnings generation capacities. I also consider the distance of a firm from meeting its earnings target using the two methods of earnings management. My results indicate that when real earnings management and accruals management are both costly, firms tend to use both methods. However, as R&D activities are important for R&D intensive firms, they tend to use abnormal accruals more than abnormal R&D to manage their earnings. Based on such findings, I construe that the nature of the firm's activities and the distance of the earnings from the earnings target influence a firm's use of real earnings management and accruals management to meet its earnings target

    Modular curvature for toric noncommutative manifolds

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    A general question behind this paper is to explore a good notion for intrinsic curvature in the framework of noncommutative geometry started by Alain Connes in the 80s. It has only recently begun (2014) to be comprehended via the intensive study of modular geometry on the noncommutative two tori. In this paper, we extend recent results on the modular geometry on noncommutative two tori to a larger class of noncommutative manifolds: toric noncommutative manifolds. The first contribution of this work is a pseudo differential calculus which is suitable for spectral geometry on toric noncommutative manifolds. As the main application, we derive a general expression for the modular curvature with respect to a conformal change of metric on toric noncommutative manifolds. By specializing our results to the noncommutative two and four tori, we recovered the modular curvature functions found in the previous works. An important technical aspect of the computation is that it is free of computer assistance.Comment: 59 pages. The paper was reorganized from the previous versio

    Latino Immigration and the Low-Skill Urban Labor Market in Atlanta

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    This report examines the dynamic competition between Latino immigrants and black workers in Atlanta's low-skilled urban labor market from 1990 to 2008