373 research outputs found
Basel II, External Ratings and Adverse Selection
This paper will describe and analyse the development of Basel II Capital Accord and will focus on the use of external ratings in the Standardized Approach in Basel II. Furthermore it will examine the problem of adverse selection which appears in Basel II as a result from the proposal for the use of external ratings in determining the risk weights in the standardized approach. The paper will also attempt to find possible solutions to the adverse selection problem by discussing two similar models, and derive implications from them.Basel II, external ratings, adverse selection, rating agencies, standardized approach
Análise e medida de fatores que afetam as curvaturas retardadas em porcelanato
Os revestimentos cerâmicos de porcelanato, tanto os esmaltados como os não esmaltados, apresentam
um fenômeno conhecido como “curvaturas retardadas”, que consiste na mudança de curvatura das peças depois
da saída do forno. Este fenômeno é mais problemático a medida de aumentam as dimensões das peças. Neste
trabalho se quantificou a variação da curvatura ao longo do tempo em peças industriais de porcelanato esmaltado,
observando-se que a curvatura parece apresentar uma evolução em um sentido (habitualmente em direção ao
sentido côncavo, ou em forma de barco) para, após transcorrido certo tempo, inverter esta tendência. A cinética
deste processo foi parametrizada considerando que existem dois mecanismos, simultâneos e antagônicos, com
cinéticas diferentes.As análises teóricas apontam que somente existem dois fatores que podem produzir curvaturas
retardadas: as tensões residuais e a expansão dos suportes. Em ambos os casos é necessário condições adicionais
para que as curvaturas efetivamente se manifestem: Deste modo, por exemplo, a presença de tensões residuais
não é sinônimo de curvaturas retardadas, mais sim um mecanismo adicional que permita a liberação progressiva
destas tensões; este mecanismo é chamado de fluência. Além disso é necessário que o perfil de tensões residuais
não seja simétrico em relação ao plano central da peça. No que diz respeito a expansão dos suportes, também são
necessárias condições especiais para que estas possam provocar curvaturas retardadas; em particular, é necessário
que estas sejam diferentes nas duas faces da peça (face lisa e tardoz). Uma expansão uniforme provocaria uma
leve mudança dimensional, mas não uma curvatura retardada, nem mesmo para peças esmaltadas. A medida dos
fatores que influenciam sobre as curvaturas retardadas é complexa pois requer o emprego de técnicas diferentes
das habitualmente empregadas para a caracterização de revestimentos cerâmicos. Foram criados, especialmente
para este trabalho, procedimentos para a medida dos diferentes fatores que produzem as curvaturas retardadas e
se estudou a influencia de algumas variáveis sobre estes fatoresGlazed and unglazed porcelain tiles exhibit a phenomenon known as delayed curvatures, which consists of the change in tile curvature after the tiles leave the kiln. This phenomenon becomes more problematic as tile size increases. In this study, the variation of curvature in time has been quantified in industrial glazed porcelain tiles. It was observed that the curvature usually displays an evolution in one direction (customarily in a concave direction or vessel shape) which, after a certain time has elapsed, reverses this trend. The kinetics of this process has been parameterised, assuming there are two simultaneous, opposing mechanisms, with different kinetics. Theoretical analyses indicate that only two factors can produce delayed curvatures: residual stresses and expansion of the tile body. In both cases, additional circumstances need to occur for delayed curvatures to appear; thus, for example, the presence of residual stresses is not synonymous with delayed curvatures, but an additional mechanism is needed that allows progressive release of these stresses, a mechanism known as creep. In addition, the condition that the stress profile is not symmetrical with respect to the centre plane of the tile also needs to be obeyed. In regard to the expansion of the bodies, special conditions must also occur for these to cause delayed curvatures. In particular, it is necessary for the expansion at the tile fair face and at the rib face to be different. Uniform expansion would cause a slight dimensional change, but not a delayed curvature, not even in the presence of glaze. The measurement of the factors that influence delayed curvatures is complex because different techniques from those typically used in characterising ceramic tiles are required. Procedures have been fine-tuned to measure the different factors that give rise to delayed curvatures, and the influence of certain variables on these factors has been studiedVersió editoria
Basel II, External Ratings and Adverse Selection
This paper will describe and analyse the development of Basel II Capital Accord and will focus on the use of external ratings in the Standardized Approach in Basel II. Furthermore it will examine the problem of adverse selection which appears in Basel II as a result from the proposal for the use of external ratings in determining the risk weights in the standardized approach. The paper will also attempt to find possible solutions to the adverse selection problem by discussing two similar models, and derive implications from them
Basel II, External Ratings and Adverse Selection
This paper will describe and analyse the development of Basel II Capital Accord and will focus on the use of external ratings in the Standardized Approach in Basel II. Furthermore it will examine the problem of adverse selection which appears in Basel II as a result from the proposal for the use of external ratings in determining the risk weights in the standardized approach. The paper will also attempt to find possible solutions to the adverse selection problem by discussing two similar models, and derive implications from them
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Pseudorapidity Dependence of Particle Production and Elliptic Flow in Asymmetric Nuclear Collisions of p+Al, p+Au, d+Au, and ^{3}He+Au at sqrt[s_{NN}]=200 GeV.
Asymmetric nuclear collisions of p+Al, p+Au, d+Au, and ^{3}He+Au at sqrt[s_{NN}]=200 GeV provide an excellent laboratory for understanding particle production, as well as exploring interactions among these particles after their initial creation in the collision. We present measurements of charged hadron production dN_{ch}/dη in all such collision systems over a broad pseudorapidity range and as a function of collision multiplicity. A simple wounded quark model is remarkably successful at describing the full data set. We also measure the elliptic flow v_{2} over a similarly broad pseudorapidity range. These measurements provide key constraints on models of particle emission and their translation into flow
In-Medium Effects on K0 Mesons in Relativistic Heavy-Ion Collisions
We present the transverse momentum spectra and rapidity distributions of
and K in Ar+KCl reactions at a beam kinetic energy of 1.756 A
GeV measured with the spectrometer HADES. The reconstructed K sample is
characterized by good event statistics for a wide range in momentum and
rapidity. We compare the experimental and K distributions to
predictions by the IQMD model. The model calculations show that K at low
tranverse momenta constitute a particularly well suited tool to investigate the
kaon in-medium potential. Our K data suggest a strong repulsive in-medium
K potential of about 40 MeV strength.Comment: 10 pages, 10 figures, accepted by Phys. Rev.
Hyperon production in Ar+KCl collisions at 1.76A GeV
We present transverse momentum spectra, rapidity distribution and
multiplicity of Lambda-hyperons measured with the HADES spectrometer in the
reaction Ar(1.76A GeV)+KCl. The yield of Xi- is calculated from our previously
reported Xi-/(Lambda+Sigma0) ratio and compared to other strange particle
multiplicities. Employing a strangeness balance equation the multiplicities of
the yet unmeasured charged Sigma hyperons can be estimated. Finally a
statistical hadronization model is used to fit the yields of pi-, K+, K0s, K-,
phi, Lambda and Xi-. The resulting chemical freeze-out temperature of T=(76+-2)
MeV is compared to the measured slope parameters obtained from fits to the
transverse mass distributions of the particles
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Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions.
The PHENIX collaboration presents first measurements of low-momentum (0.41 GeV/c) direct-photon yield dN_{γ}^{dir}/dη is a smooth function of dN_{ch}/dη and can be well described as proportional to (dN_{ch}/dη)^{α} with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high p_{T} (>5 GeV/c), but when results from different collision energies are compared, an additional sqrt[s_{NN}]-dependent multiplicative factor is needed to describe the integrated-direct-photon yield
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