Importance of Granular Structure in the Initial Conditions for the Elliptic Flow

We show effects of granular structure of the initial conditions (IC) of hydrodynamic description of high-energy nucleus-nucleus collisions on some observables, especially on the elliptic-flow parameter v2. Such a structure enhances production of isotropically distributed high-pT particles, making v2 smaller there. Also, it reduces v2 in the forward and backward regions where the global matter density is smaller, so where such effects become more efficacious.Comment: 4 pages, 5 figure

On the necessity to include event-by-event fluctuations in experimental evaluation of elliptical flow

Elliptic flow at RHIC is computed event-by-event with NeXSPheRIO. We show that when symmetry of the particle distribution in relation to the reaction plane is assumed, as usually done in the experimental extraction of elliptic flow, there is a disagreement between the true and reconstructed elliptic flows (15-30% for $\eta$=0, 30% for $p_\perp$=0.5 GeV). We suggest a possible way to take into account the asymmetry and get good agreement between these elliptic flows

Fluctuation of the Initial Conditions and Its Consequences on Some Observables

We show effects of the event-by-event fluctuation of the initial conditions (IC) in hydrodynamic description of high-energy nuclear collisions on some observables. Such IC produce not only fluctuations in observables but, due to their bumpy structure, several non-trivial effects appear. They enhance production of isotropically distributed high-pT particles, making v2 smaller there. Also, they reduce v2 in the forward and backward regions where the global matter density is smaller, so where such effects become more efficacious. They may also produce the so-called ridge effect in the two large-pT particle correlation.Comment: 6 pages, 6 figures, presented at the IV Workshop on Particle Correlations and Femtoscopy (WPCF2008), Krakow, Poland, 11-14 Sep 200

Fluctuations of the Initial Conditions and the Continuous Emission in Hydrodynamic Description of Two-Pion Interferometry

Within hydrodynamic approach, we study the Bose-Einstein correlation of identical pions by taking into account both event-by-event fluctuating initial conditions and continuous pion emission during the whole development of the hot and dense matter formed in high-energy collisions. Considerable deviations occur, compared to the usual hydro calculations with smooth initial conditions and a sudden freeze-out on a well defined hypersurface. Comparison with data at RHIC shows that, despite rather rough approximation we used here, this description can give account of the $m_T$ dependence of $R_L$ and $R_s$ and improves considerably the one for $R_o$ with respect to the usual version.Comment: 5 pages, 4 figure

Fluctuations in Hadronic and Nuclear Collisions

We investigate several fluctuation effects in high-energy hadronic and nuclear collisions through the analysis of different observables. To introduce fluctuations in the initial stage of collisions, we use the Interacting Gluon Model (IGM) modified by the inclusion of the impact parameter. The inelasticity and leading-particle distributions follow directly from this model. The fluctuation effects on rapidity distributions are then studied by using Landau's Hydrodynamic Model in one dimension. To investigate further the effects of the multiplicity fluctuation, we use the Longitudinal Phase-Space Model, with the multiplicity distribution calculated within the hydrodynamic model, and the initial conditions given by the IGM. Forward-backward correlation is obtained in this way.Comment: 22 pages, RevTex, 8 figures (included); Invited paper to the special issue of Foundation of Physics dedicated to Mikio Namiki's 70th. birthda

Effects of LatticeQCD EoS and Continuous Emission on Some ObseErvables

Effects of lattice-QCD-inspired equations of state and continuous emission on some observables are discussed, by solving a 3D hydrodynamics. The particle multiplicity as well as v2 are found to increase in the mid-rapidity. We also discuss the effects of the initial-condition fluctuations.Comment: 6 pages, 10 figures, prepared for Workshop on Particle Correlations and Fentoscopy, Kromeriz (Czech Republic), Aug. 15-17,200

NeXSPheRIO results on elliptic flow at RHIC and connection with thermalization

Elliptic flow at RHIC is computed event-by-event with NeXSPheRIO. Reasonable agreement with experimental results on $v_2(\eta)$ is obtained. Various effects are studied as well: reconstruction of impact parameter direction, freeze out temperature, equation of state (with or without crossover), emission mecanism.Comment: Contribution to the Proceedings of the Quark-Gluon Plasma Thermalization workshop. Content slightly increase

Disponibilite, modes et frequence de consommation des legumes traditionnels Africains dans quatre localites du burkina faso a diverses activites de maraichage : Ouagadougou, Koubri, Loumbila, Kongoussi

Les légumes traditionnels constituent une source importante de nutriments pour les ménages des pays en développement. La présente étude s’est intéressée à la diversité, à la  disponibilité, et  aux modes de consommation des légumes traditionnels africains dans des localités à  diverses activités de maraîchage au Burkina Faso. Des enquêtes de consommation alimentaire ont été réalisées auprès de 400 ménages dans quatre localités: Ouagadougou, Loumbila, Koubri et Kongoussi. Quatre principaux légumes sont retrouvés en toute saison dans les différentes localités : l’oseille (Hibiscus sabdariffa), la corète (Corchorus olitorius), l’amarante (Amaranthus cruentus) et le gombo (Abelmoschus callei). A Kongoussi d’autres légumes tels que les feuilles de morelle noire (Solanum scabrum) et de vernonia (Vernonia amygdalina) sont disponibles toute l’année. La fréquence de consommation est d’une fois par semaine pour plus de 50 % des ménages dans les zones à faible activité de maraichage, Ouagadougou, Loumbila et Koubri. A Kongoussi, plus de 45 % des ménages consomment plus d’une fois par semaine le gombo (Abelmoschus callei), les feuilles de corète (Corchorus olitorius), les feuilles d’oseille (Hibiscus sabdariffa) et les feuilles de haricot (Vigna unguiculata). Le marché est la source d’approvisionnement pour 71 % des ménages enquêtés. La saison, l’origine socio-culturelle et les habitudes alimentaires sont les principaux facteurs influant le choix des légumes. L’état frais est la principale forme de préférence des légumes. Pour l’utilisation des légumes dans les ménages, 74,25 % des ménages lavent 02 à 03 fois et découpent finement juste au moment de les préparer. Trois principaux modes de consommation ont été évoqués : la sauce, la soupe et le ragoût. La sauce est le principal mode de consommation et pour la cuisson 97,25 % procèdent par ébullition. Près de 62,50 % ; 53,33 % ; 45,22 % des ménages respectivement à Koubri, Loumbila et Ouagadougou procèdent par blanchiment et rejettent le liquide résiduel. A Ouagadougou et à Kongoussi, respectivement 66,67 % et 33,65 % des ménages pratiquant le blanchiment sont des non natifs. L’importance nutritive et l’effet antioxydant des légumes a été confirmée par près de 87% des répondants. L’étude a permis de conclure que l’activité de maraichage influe positivement sur la disponibilité, la diversité et la fréquence de consommation des légumes dans les ménages. Cependant des séances de sensibilisation sur les traitements post récoltes et les procédés de transformation des légumes sont nécessaires pour en tirer un meilleur profit au plan nutritionnel.Mots clés : légumes, maraîchage, diversité, traitement, blanchiment, cuisson, saison,consommatio

Correlations and the relativistic structure of the nucleon self-energy

A key point of Dirac Brueckner Hartree Fock calculations for nuclear matter is to decompose the self energy of the nucleons into Lorentz scalar and vector components. A new method is introduced for this decomposition. It is based on the dependence of the single-particle energy on the small component in the Dirac spinors used to calculate the matrix elements of the underlying NN interaction. The resulting Dirac components of the self-energy depend on the momentum of the nucleons. At densities around and below the nuclear matter saturation density this momentum dependence is dominated by the non-locality of the Brueckner G matrix. At higher densities these correlation effects are suppressed and the momentum dependence due to the Fock exchange terms is getting more important. Differences between symmetric nuclear matter and neutron matter are discussed. Various versions of the Bonn potential are considered.Comment: 18 pages LaTeX, including 6 figure