Re-Hardening of Hadron Transverse Mass Spectra in Relativistic Heavy-Ion Collisions

We analyze the spectra of pions and protons in heavy-ion collisions at relativistic energies from 2 A GeV to 65+65 A GeV by using a jet-implemented hadron-string cascade model. In this energy region, hadron transverse mass spectra first show softening until SPS energies, and re-hardening may emerge at RHIC energies. Since hadronic matter is expected to show only softening at higher energy densities, this re-hardening of spectra can be interpreted as a good signature of the quark-gluon plasma formation.Comment: 10 pages, 3 figures, 1 table, Poster presentation at QM2001, Revised to correct latex error in citation on April 6, 200

Ville et littérature : les transformations urbaines de Paris au XVIIème siècle

L’aspect du Paris moderne est toujours correctement attribué à Haussmann qui, de 1853 à 1870, redessine la morphologie de la capitale. Néanmoins, l’inscription de modifications durables dans la physionomie de la ville commence bien avant le Second Empire. Nous prétendons le prouver ici pour le XVIIème siècle. Après avoir contextualisé la croissance et les problèmes de Paris, nous examinons les transformations urbaines à l’époque. Enfin, nous signalons quelques échos de celles-ci dans des oeuvres littéraires. La présente étude se situe dans la continuité de travaux que nous avons présentés et/ou publiés auparavant sur les transformations de Paris au long de son histoire. Cadre de référence: recherche et enseignement de la «civilisation française» (Cultura Francesa) en FLE. Perspective: thématique (la ville), mais aussi didactique et littéraire (donner une idée du genre de travail susceptible d'être réalisé sur cette question en cours à l’université ou à l’Alliance française, en y travaillant aussi les dialogues entre la littérature et les faits urbains). Fondements théoriques: l’histoire (de France, de Paris), l’urbanisme et l’architecture (théorie et histoire), la littérature française (histoire, études littéraires, études thématiques: la ville) et leurs croisements: littérature et histoire; ville et littérature. Les auteurs sont ceux cités dans la bibliographie. Notre méthodologie est bibliographique.Fil: Ponge, Robert. Universidade Federal do Rio Grande do Sul (Brasil)Fil: Machado, Nara Helena N.. Pontifícia Universidade Católica do Rio Grande do Su

Back-to-back correlations of high p_T hadrons in relativistic heavy ion collisions

We investigate the suppression factor and the azimuthal correlation function for high $p_T$ hadrons in central Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV by using a dynamical model in which hydrodynamics is combined with explicitly traveling jets. We study the effects of parton energy loss in a hot medium, intrinsic $k_T$ of partons in a nucleus, and $p_{\perp}$ broadening of jets on the back-to-back correlations of high $p_T$ hadrons. Parton energy loss is found to be a dominant effect on the reduction of the away-side peaks in the correlation function.Comment: 4 pages, 4 figures; version to appear in Phys. Rev. Let

Macular Pigment and Visual Function in Patients With Glaucoma: The San Diego Macular Pigment Study.

PurposeAlthough recent studies have shown that macular pigment (MP) is significantly lower in glaucoma patients, this relationship merits further investigation.MethodsThis cross-sectional study included 85 glaucoma patients and 22 controls. All subjects had standard automated perimetry (SAP) and retinal nerve fiber layer (RNFL) thickness measurements. Intake of lutein (L) and zeaxanthin (Z) was estimated using a novel dietary screener. The Heidelberg Spectralis dual-wavelength autofluorescence (AF) technology was employed to study the relationship between MP and glaucoma. The association between MP volume and glaucoma was investigated using linear regression models accounting for potential confounding factors.ResultsGlaucoma patients had significantly worse SAP mean deviation (MD) and lower RNFL thickness in the study eye compared to control subjects (P < 0.001 for both). MP (volume) was comparable between groups (P = 0.436). In the univariable model, diagnosis of glaucoma was not associated with MP volume (R2 = 1.22%; P = 0.257). Dietary intake of L and Z was positively and significantly related to MP in the univariable (P = 0.022) and multivariable (P = 0.020) models.ConclusionsThese results challenge previous studies that reported that glaucoma is associated with low MP. Dietary habits were found to be the main predictor of MP in this sample. Further research is merited to better understand the relationship between glaucoma, MP, and visual performance in these patients

Anais do Seminário Nacional Vanguardas, Surrealismo e Modernidade : Europa e Américas

Estes anais reúnem os trabalhos que, após apresentação no Seminário Nacional Vanguardas, Surrealismo e Modernidade: Europa e Américas, foram entregues, no prazo estabelecido, por seus autores à Comissão Organizadora do Congresso; foram todos submetidos a processo de avaliação por pareceristas, desenvolvido pela Comissão Científica de Publicação dos Anais, com a colaboração de pareceristas ad hoc externos à Comissão e à UFRGS, sob a coordenação de Robert Ponge, Ruben Daniel Méndez Castiglioni, Janaína de Azevedo Baladão e Nara H. N. Machado. – Os coordenadores do evento agradecem: aos professores Michael Korfmann e Gerson R. Neumann, editores da Contingentia, por acolher a publicação dos anais nas páginas de sua revista; à acadêmica Gabriela W. Linck, monitora da revista, pelas tarefas decorrentes da inserção dos anais na Contingentia

Electron transport in Coulomb- and tunnel-coupled one-dimensional systems

We develop a linear theory of electron transport for a system of two identical quantum wires in a wide range of the wire length L, unifying both the ballistic and diffusive transport regimes. The microscopic model, involving the interaction of electrons with each other and with bulk acoustical phonons allows a reduction of the quantum kinetic equation to a set of coupled equations for the local chemical potentials for forward- and backward-moving electrons in the wires. As an application of the general solution of these equations, we consider different kinds of electrical contacts to the double-wire system and calculate the direct resistance, the transresistance, in the presence of tunneling and Coulomb drag, and the tunneling resistance. If L is smaller than the backscattering length l_P, both the tunneling and the drag lead to a negative transresistance, while in the diffusive regime (L >>l_P) the tunneling opposes the drag and leads to a positive transresistance. If L is smaller than the phase-breaking length, the tunneling leads to interference oscillations of the resistances that are damped exponentially with L.Comment: Text 14 pages in Latex/Revtex format, 4 Postscript figure

Study of relativistic nuclear collisions at AGS energies from p+Be to Au+Au with hadronic cascade model

A hadronic cascade model based on resonances and strings is used to study mass dependence of relativistic nuclear collisions from p+Be to Au+Au at AGS energies (\sim 10\AGeV) systematically. Hadron transverse momentum and rapidity distributions obtained with both cascade calculations and Glauber type calculations are compared with experimental data to perform detailed discussion about the importance of rescattering among hadrons. We find good agreement with the experimental data without any change of model parameters with the cascade model. It is found that rescattering is of importance both for the explanation of high transverse momentum tail and for the multiplicity of produced particles.Comment: 27 pages, 30 figure