1,158 research outputs found
On the rescaled Riemannian metric of Cheeger Gromoll type on the cotangent bundle
Let be an n-dimensional Riemannian manifold and 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
and construct almost paracomplex Norden structures on . 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
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
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
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 Ăâoriginate and holdĂâ to Ăâoriginate, repackage and sellĂâ has also modified banksĂâ 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 banksĂâ 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 banksĂâ 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
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?
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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