52 research outputs found

    Hinting at primary composition using asymmetries in time distributions

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    Evidence of azimuthal asymmetries in the time structure and signal size have been found in non-vertical showers at the Pierre Auger Observatory. It has been previously shown that the asymmetry in time distributions offers a new possibility for the determination of the mass composition. New studies have demonstrated that the dependence of the asymmetry parameter in the rise-time and fall-time distributions with sec(theta) shows a clear peak. Both, the position of the peak, X_asymax, and the size of the asymmetry at X_asymax are sensitive to primary mass composition and have a small dependence on energy. In this paper a study of the discriminating power of the new observables to separate primary species is presented.Comment: To be published in the Proceedings of 29th International Cosmic Ray Conference (ICRC 2005), Pune, India, August 3-10, 200

    An upper limit to the photon fraction in cosmic rays above 10^19 eV from the Pierre Auger Observatory

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    An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies above 10^19 eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory. This is the first such limit on photons obtained by observing the fluorescence light profile of air showers. This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays. Additional data recorded with the Auger surface detectors for a subset of the event sample, support the conclusion that a photon origin of the observed events is not favoured

    Eficacia y seguridad del tratamiento con lenalidomida y dexametasona en pacientes con mieloma múltiple no candidatos a trasplante en recaída

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    PO-019 Introducción: En la actualidad existe una amplia diversidad de tratamientos en pacientes con Mieloma Múltiple (MM) refractarios a tratamiento en primera línea y no candidatos a trasplante de progenitores hematopoyéticos. El tratamiento de estos pacientes con lenalidomida y dexametasona ha sido una de las opciones terapeúticas más utilizadas en los últimos años. El objetivo de este estudio es evaluar la eficacia y tolerabilidad de este tratamiento en un centro hospitalario de tercer nivel. Material Y Métodos: Estudio descriptivo, observacional y retrospectivo en el que se incluyeron todos los pacientes no candidatos a TPH que iniciaron un esquema con lenalidomida entre Enero 2012 a Marzo 2019 y además recibieron al menos una línea previa de quimioterapia. Fuentes: historia clínica electrónica, registro de dispensación de pacientes ambulatorios y externos (FarmaTools) del Servicio de Farmacia. Resultados: En total 22 pacientes (50% mujeres) fueron incluidos en el estudio. La mediana de numero de líneas que recibieron previamente fue de 1(rango entre 1-2). 17 pacientes (77%) recibieron RD como 2º línea y para 5 pacientes (33%) fue la 3ª línea. Como tratamiento en 1ª línea, solo 1 paciente recibió tratamiento con QT convencional (VAD), ..

    Astrophysical Origins of Ultrahigh Energy Cosmic Rays

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    In the first part of this review we discuss the basic observational features at the end of the cosmic ray energy spectrum. We also present there the main characteristics of each of the experiments involved in the detection of these particles. We then briefly discuss the status of the chemical composition and the distribution of arrival directions of cosmic rays. After that, we examine the energy losses during propagation, introducing the Greisen-Zaptsepin-Kuzmin (GZK) cutoff, and discuss the level of confidence with which each experiment have detected particles beyond the GZK energy limit. In the second part of the review, we discuss astrophysical environments able to accelerate particles up to such high energies, including active galactic nuclei, large scale galactic wind termination shocks, relativistic jets and hot-spots of Fanaroff-Riley radiogalaxies, pulsars, magnetars, quasar remnants, starbursts, colliding galaxies, and gamma ray burst fireballs. In the third part of the review we provide a brief summary of scenarios which try to explain the super-GZK events with the help of new physics beyond the standard model. In the last section, we give an overview on neutrino telescopes and existing limits on the energy spectrum and discuss some of the prospects for a new (multi-particle) astronomy. Finally, we outline how extraterrestrial neutrino fluxes can be used to probe new physics beyond the electroweak scale.Comment: Higher resolution version of Fig. 7 is available at http://www.angelfire.com/id/dtorres/down3.html. Solicited review article prepared for Reports on Progress in Physics, final versio

    Case 2801. Potamolithus Pilsbry, 1896 (Mollusca, Gastropoda): Proposed Confirmation Of P. Rushii Pilsbry, 1896 As The Type Species

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    Volume: 49Start Page: 109End Page: 11

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    The dating of certain of d'Orbigny's brachiopod and bivalve nominal taxa

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    Volume: 50Start Page: 196End Page: 19
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