1,933 research outputs found

    Yeasts isolated from different European dry-sausages in the course of ripening

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    The evolution in counts of yeasts from six lots of different dry-sausages produced in three European Union (EU) countries (France, Italy and Spain) is tested. Each lot was analyzed in three phases of their production: fresh product, first staged drying and final product. Three samples were analyzed in each test. Counts of yeasts during the ripening process showed an irregular evolution. Regarding the species isolated, the most frequent ones belonged to genera Candida (C. albicans, C. famata, C. guillermondii, C. krusei, C. parapsilosis, C. stellatoidea, C. zeylanoides.), Trichosporon (T. capitatum, T. beigelli), Rhodotorula and Geotrichum (G. candidum)

    Insights on the climatic evolution at the pre-Jaramillo to Jaramillo transition in Europe using mineralogical analysis of the Quibas palaeontological site (Early Pleistocene, southern Iberian Peninsula)

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    © The Authors, 2023. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (for details please see http://creativecommons.org/licenses/by/4.0/), which permits use, copy, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source. This document is the Published version of a Published Work that appeared in final form in Spanish Journal of Palaeontology. To access the final edited and published work see https://doi.org/10.7203/sjp.27562The palaeontological site of Quibas is a karst outcrop with an age between 1.1 and 0.9 Ma (late Early Pleistocene). It represents the unique continuous sequence of terrestrial vertebrates of pre-Jaramillo to Jaramillo age in Europe. It is formed by two main structures: Quibas-Sima (divided into units QS-1 to QS-7) and Quibas-Cueva (QC-1– QC-6). In this work, we analyse the mineralogical composition of the sediments that form the stratigraphic units of Quibas-Sima using X-ray diffraction analysis, electrical conductivity, ion chromatography and optical emission spectrometry, to evaluate climatic trends in the sequence. Preliminary results indicate that there is an increase in the proportions of carbonates, gypsum and halite from QS-2 towards QS-4 and QS-5 (1.07–0.99 Ma), suggesting a progressive decrease in precipitation in south-eastern Iberian Peninsula a million years ago. Our data are consistent with the onset of a glacial phase, which is supported by the progressive disappearance of taxa related to forests and water bodies in Quibas-Sima, such as the flying squirrel Hylopetes sp. and the semiaquatic shrew Neomys sp., in favour of the appearance of taxa linked to open areas such as the Montpellier snake (Malpolon monspessulanus) and the snub-nosed viper (Vipera latastei). El yacimiento paleontológico de Quibas es un afloramiento kárstico con una edad comprendida entre 1,1 y 0,9 Ma (Pleistoceno Inferior tardío). Representa la única secuencia continua de vertebrados terrestres de edad pre-Jaramillo a Jaramillo de Europa. Está formado por dos estructuras principales: Quibas-Sima (dividida en las unidades QS-1 a QS-7) y Quibas-Cueva (QC-1 a QC-6). En este trabajo se estudia la composición mineralógica de los sedimentos que conforman las unidades estratigráficas de QuibasSima, a través e análisis de difracción de rayos X, conductividad eléctrica, cromatografía iónica y espectrometría de emisión óptica por plasma de argón, con el objetivo de evaluar tendencias paleoclimáticas en la secuencia. Los resultados preliminares indican que hay un aumento en las proporciones de carbonatos, yesos y halita desde QS-2 hacia QS-4 y QS-5 (1,07–0,99 Ma), lo que sugiere una progresiva disminución de las precipitaciones en el sureste peninsular hace un millón de años. Los datos son consistentes con el inicio de una fase glaciar, lo cual viene apoyado por la desaparición progresiva en Quibas-Sima de taxones afines a bosques y cursos de agua estables como la ardilla voladora Hylopetes sp. y el musgaño Neomys sp., en favor de la aparición de taxones ligados a espacios abiertos como la culebra bastarda (Malpolon monspessulanus) y la víbora hocicuda (Vipera latastei)

    The 1989 and 2015 outbursts of V404 Cygni: a global study of wind-related optical features

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    The black hole transient V404 Cygni exhibited a bright outburst in June 2015 that was intensively followed over a wide range of wavelengths. Our team obtained high time resolution optical spectroscopy (~90 s), which included a detailed coverage of the most active phase of the event. We present a database consisting of 651 optical spectra obtained during this event, that we combine with 58 spectra gathered during the fainter December 2015 sequel outburst, as well as with 57 spectra from the 1989 event. We previously reported the discovery of wind-related features (P-Cygni and broad-wing line profiles) during both 2015 outbursts. Here, we build diagnostic diagrams that enable us to study the evolution of typical emission line parameters, such as line fluxes and equivalent widths, and develop a technique to systematically detect outflow signatures. We find that these are present throughout the outburst, even at very low optical fluxes, and that both types of outflow features are observed simultaneously in some spectra, confirming the idea of a common origin. We also show that the nebular phases depict loop patterns in many diagnostic diagrams, while P-Cygni profiles are highly variable on time-scales of minutes. The comparison between the three outbursts reveals that the spectra obtained during June and December 2015 share many similarities, while those from 1989 exhibit narrower emission lines and lower wind terminal velocities. The diagnostic diagrams presented in this work have been produced using standard measurement techniques and thus may be applied to other active low-mass X-ray binaries.Comment: Accepted for publication in MNRAS. 23 pages paper, plus a 9 pages appendix with extra tables and figures. 18 figures are included in the paper and 8 in the appendi

    The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

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    The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR

    VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

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    VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

    Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV

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    A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected particle and one or two jets

    Search for anomalous t t-bar production in the highly-boosted all-hadronic final state

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    A search is presented for a massive particle, generically referred to as a Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze jet substructure, providing suppression of the non-top multijet backgrounds. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits in the range of 1 pb are set on the product of the production cross section and branching fraction for a topcolor Z' modeled for several widths, as well as for a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any enhancement in t t-bar production beyond expectations of the standard model for t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version includes a minor typo correction that will be submitted as an erratu
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