Redefining the role of obstacles in pedestrian evacuation

The placement of obstacles in front of doors is believed to be an effective strategy to increase the flow of pedestrians, hence improving the evacuation process. Since it was first suggested, this counterintuitive feature is considered a hallmark of pedestrian flows through bottlenecks. Indeed, despite the little experimental evidence, the placement of an obstacle has been hailed as the panacea for solving evacuation problems. In this work, we challenge this idea and experimentally demonstrate that the pedestrians flow rate is not necessarily altered by the presence of an obstacle. This result - which is at odds with recent demonstrations on its suitability for the cases of granular media, sheep and mice - differs from the outcomes of most of existing numerical models, and warns about the risks of carelessly extrapolating animal behaviour to humans. Our experimental findings also reveal an unnoticed phenomenon in relation with the crowd movement in front of the exit: in competitive evacuations, an obstacle attenuates the development of collective transversal rushes, which are hazardous as they might cause falls.Fil: Garcimartín, A.. Universidad de Navarra; EspañaFil: Maza, D.. Universidad de Navarra; EspañaFil: Pastor, J. M.. Focke Meler Gluing Solutions S.A.; EspañaFil: Parisi, Daniel Ricardo. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martín Gómez, C.. Universidad de Navarra; EspañaFil: Zuriguel, I.. Universidad de Navarra; Españ

The J/ψDDJ/\psi D D Vertex in QCD Sum Rules

The $J/\psi D D$ form factor is evaluated in a QCD sum rule calculation for both $D$ and $J/\psi$ off-shell mesons. We study the double Borel sum rule for the three point function of two pseudoscalar and one vector meson current. We find that the momentum dependence of the form factors is different if the $D$ or the $J/\psi$ meson is off-shell, but they lead to the same coupling constant in the $J/\psi D D$ vertex.Comment: 11 pages, Latex, 4 eps figure

Charmonium Absorption in the Meson-exchange Model

We review the meson-exchange model for charmonium absorption by hadrons. This includes the construction of the interaction Lagrangians, the determination of the coupling constants, the introduction of form factors, and the predicted cross sections for $J/\psi$ absorption by both mesons and nucleons. We further discuss the effects due to anomalous parity interactions, uncertainties in form factors, constraints from chiral symmetry, and the change of charmed meson mass in medium on the cross sections for charmonium absorption in hadronic matter.Comment: 10 pages, 2 figures. Talk given at Quark Matter 2002 (QM 2002), Nantes, France, 18-24 July 2002. To appear in the proceedings (Nucl. Phys. A

Effect of Chiral Symmetry Restoration on Pentaquark Θ+\Theta^+ Mass and Width at Finite Temperature and Density

We investigate the effect of chiral phase transition on the pentaquark $\Theta^+$ mass and width at one-loop level of $N\Theta^+K$ coupling at finite temperature and density. The behavior of the mass, especially the width in hadronic medium is dominated by the characteristics of chiral symmetry restoration at high temperature and high density. The mass and width shifts of positive-parity $\Theta^+$ are much larger than that of negative-parity one, which may be helpful to determine the parity of $\Theta^+$ in high energy nuclear collisions.Comment: 7 pages, 5 figure

Υ\Upsilon absorption in hadronic matter

The cross sections of $\Upsilon$ absorption by $\pi$ and $\rho$ mesons are evaluated in a meson-exchange model. Including form factors with a cutoff parameter of 1 or 2 GeV, we find that due to the large threshold of these reactions the thermal average of their cross sections is only about 0.2 mb at a temperature of 150 MeV. Our results thus suggest that the absorption of directly produced $\Upsilon$ by hadronic comovers in high energy heavy ion collisions is unimportant.Comment: 11 pages, revtex, 3 figures, added references and discussion on higher BBbar state

Investigation of the Properties of Galactic Cosmic Rays with the KASCADE-Grande Experiment

The properties of galactic cosmic rays are investigated with the KASCADE-Grande experiment in the energy range between $10^{14}$ and $10^{18}$ eV. Recent results are discussed. They concern mainly the all-particle energy spectrum and the elemental composition of cosmic rays.Comment: Proc. RICAP 09, Nucl. Instr. and Meth. in pres

The rate of cosmic ray showers at large zenith angles: a step towards the detection of ultra-high energy neutrinos by the Pierre Auger Observatory

It is anticipated that the Pierre Auger Observatory can be used to detect cosmic neutrinos of >10^19 eV that arrive at very large zenith angles. However showers created by neutrino interactions close to the detector must be picked out against a background of similar events initiated by cosmic ray nuclei. As a step towards understanding this background, we have made the first detailed analysis of air showers recorded at Haverah Park (an array which used similar detectors to those planned for the Auger Observatory) with zenith angles above 60 degs. We find that the differential shower rate from 60 degs to 80 degs. can be predicted accurately when we adopt the known primary energy spectrum above 10^17 eV and assume the QGSJET model and proton primaries. Details of the calculation are given.Comment: 22 pages, 12 figures, to appear in Astroparticle Physic

La incorporación sociolaboral en el Plan de Lucha contra la Exclusión en Navarra

El Plan de Lucha contra la Exclusión en Navarra 1998-2005 fue aprobado por el Gobierno de Navarra en junio de 1998 y ratificado por el Parlamento de Navarra en febrero de 1999. Su elaboración fue el resultado de un proceso que se inició en 1996, con el encargo de varios estudios previos al Grupo de Investigación sobre Exclusión Social de la Universidad Pública de Navarra. Estos trabajos incluyeron una evaluación del programa de Renta Básica entre 1990 y 1996 y una investigación sobre la exclusión social en Navarra. Finalizados estos estudios, un equipo técnico conjunto del Gobierno de Navarra y la Universidad Pública de Navarra elaboraron un anteproyecto que fue tomado como punto de partida para su discusión entre los diferentes departamentos del Gobierno, en primer lugar, y en el Parlamento Foral, en un segundo momento