1,158 research outputs found

    On the rescaled Riemannian metric of Cheeger Gromoll type on the cotangent bundle

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    Let (M,g)(M,g) be an n-dimensional Riemannian manifold and T∗MT^{*}M be its cotangent bundle equipped with a Riemannian metric of Cheeger Gromoll type which rescale the horizontal part by a nonzero differentiable function. The main purpose of the present paper is to discuss curvature properties of T∗MT^{*}M and construct almost paracomplex Norden structures on T∗MT^{*}M. We investigate conditions for these structures to be para-K\"ahler (paraholomorphic) and quasi-K\"ahler. Also, some properties of almost paracomplex Norden structures in context of almost product Riemannian manifolds are presented

    TOTEM: The experiment to measure the total proton-proton cross section at LHC

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    The current large uncertainty on the extrapolation of the proton-proton total cross section at the LHC energy will be resolved by the precise measurement by the TOTEM experiment. Its accurate studies on the basic properties of proton-proton collisions at the maximum accelerator energy could provide a significant contribution to the understanding of cosmic ray physics.Comment: 6 pages, 7 figures, Proceedings XIV International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2006), Weihai, China, August 15-22, 200

    Mergers and acquisitions and bank performance in Europe: the role of strategic similarities

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    An unprecedented process of financial consolidation has taken place in the European Union over the past decade. Building on earlier US evidence, we examine the impact of strategic similarities between bidders and targets on post-merger financial performance. We find that, on average, bank mergers in the European Union resulted in improved return on capital. By making the assumption that balance-sheet resource allocation is indicative of the strategic focus of banks, we also find significantly different results for domestic and cross-border mergers. For domestic deals, it could be quite costly to integrate dissimilar institutions in terms of their loan, earnings, cost, deposits and size strategies. For cross-border mergers and acquisitions (M&As), differences of merging partners in their loan and credit risk strategies are conducive to a higher performance whereas diversity in their capital, cost structure as well as technology and innovation investments strategies are counterproductive from a performance standpoint. JEL Classification: G21, G34banks, M&As, strategic similarities

    Securitisation and the bank lending channel

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    The dramatic increase in securitisation activity has modified the functioning of credit markets by reducing the fundamental role of liquidity transformation performed by financial intermediaries. We claim that the changing role of banks from “originate and hold” to “originate, repackage and sell” has also modified banks’ abilities to grant credit and the effectiveness of the bank lending channel of monetary policy. Using a large sample of European banks, we find that the use of securitisation appears to shelter banks’ loan supply from the effects of monetary policy. Securitisation activity has also strengthened the capacity of banks to supply new loans but this capacity depends upon business cycle conditions as well as upon banks’ risk positions. In this respect the recent experience of the sub-prime mortgage loans crisis is very instructive.asset securitisation, bank lending channel, monetary policy

    Feasibility of dual-energy CBCT material decomposition in the human torso with 2D anti-scatter grids and grid-based scatter sampling

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    Background: Dual-energy (DE) imaging techniques in cone-beam computed tomography (CBCT) have potential clinical applications, including material quantification and improved tissue visualization. However, the performance of DE CBCT is limited by the effects of scattered radiation, which restricts its use to small object imaging. Purpose: This study investigates the feasibility of DE CBCT material decomposition by reducing scatter with a 2D anti-scatter grid and a measurement-based scatter correction method. Methods: A 2D anti-scatter grid prototype was utilized with a residual scatter correction method in a linac-mounted CBCT system to investigate the effects of robust scatter suppression in DE CBCT. Scans were acquired at 90 and 140 kVp using phantoms that mimic head, thorax, and abdomen/pelvis anatomies. The effect of a 2D anti-scatter grid with and without residual scatter correction on iodine concentration quantification and contrast visualization in VME images was evaluated. Results: In CBCT images, a 2D grid with or without scatter correction can differentiate iodine and water after DE processing in human torso-sized phantom images. However, iodine quantification errors were up to 10 mg/ml in pelvis phantoms when only the 2D grid was used. Adding scatter correction to 2D-grid CBCT reduced iodine quantification errors below 1.5 mg/ml in pelvis phantoms, comparable to iodine quantification errors in multidetector CT. Conclusions: This study indicates that accurate DE decomposition is potentially feasible in DE CBCT of the human torso if robust scatter suppression is achieved with 2D anti-scatter grids and residual scatter correction. This approach can potentially enable better contrast visualization and tissue and contrast agent quantification in various CBCT applications

    Does monetary policy affect bank risk-taking?

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    This paper investigates the relationship between short-term interest rates and bank risk. Using a unique database that includes quarterly balance sheet information for listed banks operating in the European Union and the United States in the last decade, we find evidence that unusually low interest rates over an extended period of time contributed to an increase in banks' risk. This result holds for a wide range of measures of risk, as well as macroeconomic and institutional controls. JEL Classification: E44, E55, G21bank risk, credit crisis, monetary policy
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