462 research outputs found

    LA EFICIENCIA TECNICA EN LAS TERMINALES DE CONTENEDORES A PARTIR DE LA LEY DE BENFORD: Aplicación a los puertos españoles

    Full text link
    [EN] Las terminales de contenedores en los puertos son los nodos del sistema de transportes derivado de un sistema abierto y complejo como es el del flujo de las mercancías en el intercambio de bienes. La eficiencia técnica se da en economía, utilizando todos sus recursos de manera eficiente, produciendo el máximo de producción con el mínimo de recursos. En la presente ponencia se demuestra que la función de distribución de equilibrio de los movimiento de contenedores en los puertos se ajusta bien a la denominada ley de Benford, del primer digito, o de distribución desigual de dígitos en datos numéricos, ley de potencia que se obtiene como resultado de maximizar la entropía de Shannon, lo que significa obtener la mayor eficiencia técnica. Del ajuste de la ley de Benford con los resultados obtenidos para los puertos españoles en los tráficos totales y de contenedores, nos abre una nueva línea de investigación para comprobar la eficiencia de los puertos y poder plantear mejoras para su funcionamiento.Pesquera Gonzalez, M.; Coto Millán, P.; Diaz Medina, B.; Castanedo Galán, J. (2016). LA EFICIENCIA TECNICA EN LAS TERMINALES DE CONTENEDORES A PARTIR DE LA LEY DE BENFORD: Aplicación a los puertos españoles. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1392-1399. https://doi.org/10.4995/CIT2016.2015.3496OCS1392139

    Soil amplifying effect on vulnerability to seismic hazard for Tolhuin, Tierra del Fuego, Argentina

    Get PDF
    La Isla Grande de Tierra del Fuego (Argentina-Chile) está situada en un entorno de intensa actividad sísmica merced a la interacción de las placas tectónicas Antártica, Scotia y Sudamericana. Dos zonas sismotectónicas en esta región: la fosa de subducción en el extremo austral de Chile Magallanes-Fagnano, que cruza la isla de este a oeste, representan una amenaza sísmica para la población local. únicamente el sector argentino de la Tierra del Fuego, sin embargo,la mayor amenaza proviene de la Fagnano, la cual ha generado eventos sísmicos de magnitud M=8 en tiempos históricos. Tolhuin, una 3000 habitantes en rápido crecimiento, está a 1 km de la traza de esta falla. Las construcciones parte no han tenido el control de sismorresistencia que requiere el INPRES (Instituto Nacional de Prevención otra parte, la urbanización de Tolhuin apoya sobre un espeso paquete de sedimentos glacigénicos del Cuaternario cuyas características geotécnicas sugieren que puede amplificar a más del doble una vibración sísmica, de acuerdo a una simulación con EERA (Equivalent-linear Earthquake Analyses). Aplicando la metodología Risk Assessment Tools for Diagnosis of Urban Areas against Seismic Disasters (RADIUS) propiciada por las Naciones Unidas, este estudio analiza la vulnerabilidad edilicia de Tolhuin ante un Terremoto Máximo Considerado de M=8,0. Los resultados muestran la importancia de tomar en cuenta la probable amplificación local por el efecto suelo. El presente trabajo constituye un primer esfuerzo concertado para dotar a la provincia argentina de Tierra del Fuego de herramientas cartográficas y conceptuales útiles para planificar el crecimiento urbano tomando en cuenta la prevención sísmica.The island of Tierra del Fuego (Argentina-Chile) lies in a region of intense seismic activity due to the interaction of the Antarctica, Scotia and South American tectonic plates. Two seismotectonic zones in this region: the subduction trench in southernmost Chile and the Magallanes-Fagnano fault, that crosses the island from east to west, represent a seismic hazard for the island population. Focusing on the Argentine sector of Tierra del Fuego, however, the greater threat comes from the Magallanes-Fagnano fault, which has generated seismic events in historical times of magnitude M=8. Tolhuin, a small population of 3000 inhabitants undergoing fast growth, is located 1 km from the trace of the Magallanes-Fagnano fault. Buildings in Tolhuin largely have not had seismic safety controls required by the INPRES (the Argentine seismic building code regulator). In addition, the urbanization of Tolhuin rests on a thick package of Quaternary glacigenic sediments with the potential for amplifying seismic vibrations by a factor of more than 2, judging from a simulation with EERA (Equivalent-linear Earthquake Analyses). Applying the Risk Assessment Tools for Diagnosis of Urban Areas against Seismic Disasters (RADIUS) methodology, supported by the United Nations, this study analyses the seismic vulnerability of constructions in Tolhuin under the effect of a Maximum Considered Earthquake of magnitude M=8.0. The results show the importance of considering the probable local amplification through site effects. This study constitutes a first effort to provide the Argentine province of Tierra del Fuego with cartographic and conceptual tools useful in planning urban growth taking into consideration seismic hazard.Fil: Abascal, Liliana del Valle. Universidad Tecnológica Nacional. Facultad Regional Río Grande; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gonzalez Bonorino, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Bujalesky, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Coto, Claudio Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

    The 2HWC HAWC Observatory Gamma Ray Catalog

    Full text link
    We present the first catalog of TeV gamma-ray sources realized with the recently completed High Altitude Water Cherenkov Observatory (HAWC). It is the most sensitive wide field-of-view TeV telescope currently in operation, with a 1-year survey sensitivity of ~5-10% of the flux of the Crab Nebula. With an instantaneous field of view >1.5 sr and >90% duty cycle, it continuously surveys and monitors the sky for gamma ray energies between hundreds GeV and tens of TeV. HAWC is located in Mexico at a latitude of 19 degree North and was completed in March 2015. Here, we present the 2HWC catalog, which is the result of the first source search realized with the complete HAWC detector. Realized with 507 days of data and represents the most sensitive TeV survey to date for such a large fraction of the sky. A total of 39 sources were detected, with an expected contamination of 0.5 due to background fluctuation. Out of these sources, 16 are more than one degree away from any previously reported TeV source. The source list, including the position measurement, spectrum measurement, and uncertainties, is reported. Seven of the detected sources may be associated with pulsar wind nebulae, two with supernova remnants, two with blazars, and the remaining 23 have no firm identification yet.Comment: Submitted 2017/02/09 to the Astrophysical Journa

    Daily monitoring of TeV gamma-ray emission from Mrk 421, Mrk 501, and the Crab Nebula with HAWC

    Full text link
    We present results from daily monitoring of gamma rays in the energy range 0.5\sim0.5 to 100\sim100 TeV with the first 17 months of data from the High Altitude Water Cherenkov (HAWC) Observatory. Its wide field of view of 2 steradians and duty cycle of >95>95% are unique features compared to other TeV observatories that allow us to observe every source that transits over HAWC for up to 6\sim6 hours each sidereal day. This regular sampling yields unprecedented light curves from unbiased measurements that are independent of seasons or weather conditions. For the Crab Nebula as a reference source we find no variability in the TeV band. Our main focus is the study of the TeV blazars Markarian (Mrk) 421 and Mrk 501. A spectral fit for Mrk 421 yields a power law index Γ=2.21±0.14stat±0.20sys\Gamma=2.21 \pm0.14_{\mathrm{stat}}\pm0.20_{\mathrm{sys}} and an exponential cut-off E0=5.4±1.1stat±1.0sysE_0=5.4 \pm 1.1_{\mathrm{stat}}\pm 1.0_{\mathrm{sys}} TeV. For Mrk 501, we find an index Γ=1.60±0.30stat±0.20sys\Gamma=1.60\pm 0.30_{\mathrm{stat}} \pm 0.20_{\mathrm{sys}} and exponential cut-off E0=5.7±1.6stat±1.0sysE_0=5.7\pm 1.6_{\mathrm{stat}} \pm 1.0_{\mathrm{sys}} TeV. The light curves for both sources show clear variability and a Bayesian analysis is applied to identify changes between flux states. The highest per-transit fluxes observed from Mrk 421 exceed the Crab Nebula flux by a factor of approximately five. For Mrk 501, several transits show fluxes in excess of three times the Crab Nebula flux. In a comparison to lower energy gamma-ray and X-ray monitoring data with comparable sampling we cannot identify clear counterparts for the most significant flaring features observed by HAWC.Comment: 18 pages, 10 figures, accepted for publication in The Astrophysical Journa

    The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab Nebula

    Get PDF
    MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma, Spain. During summer 2011 and 2012 it underwent a series of upgrades, involving the exchange of the MAGIC-I camera and its trigger system, as well as the upgrade of the readout system of both telescopes. We use observations of the Crab Nebula taken at low and medium zenith angles to assess the key performance parameters of the MAGIC stereo system. For low zenith angle observations, the standard trigger threshold of the MAGIC telescopes is ~50GeV. The integral sensitivity for point-like sources with Crab Nebula-like spectrum above 220GeV is (0.66+/-0.03)% of Crab Nebula flux in 50 h of observations. The angular resolution, defined as the sigma of a 2-dimensional Gaussian distribution, at those energies is < 0.07 degree, while the energy resolution is 16%. We also re-evaluate the effect of the systematic uncertainty on the data taken with the MAGIC telescopes after the upgrade. We estimate that the systematic uncertainties can be divided in the following components: < 15% in energy scale, 11-18% in flux normalization and +/-0.15 for the energy spectrum power-law slope.Comment: 21 pages, 25 figures, accepted for publication in Astroparticle Physic

    Multi-Wavelength Observations of the Blazar 1ES 1011+496 in Spring 2008

    Get PDF
    The BL Lac object 1ES 1011+496 was discovered at Very High Energy gamma-rays by MAGIC in spring 2007. Before that the source was little studied in different wavelengths. Therefore a multi-wavelength (MWL) campaign was organized in spring 2008. Along MAGIC, the MWL campaign included the Metsahovi radio observatory, Bell and KVA optical telescopes and the Swift and AGILE satellites. MAGIC observations span from March to May, 2008 for a total of 27.9 hours, of which 19.4 hours remained after quality cuts. The light curve showed no significant variability. The differential VHE spectrum could be described with a power-law function. Both results were similar to those obtained during the discovery. Swift XRT observations revealed an X-ray flare, characterized by a harder when brighter trend, as is typical for high synchrotron peak BL Lac objects (HBL). Strong optical variability was found during the campaign, but no conclusion on the connection between the optical and VHE gamma-ray bands could be drawn. The contemporaneous SED shows a synchrotron dominated source, unlike concluded in previous work based on nonsimultaneous data, and is well described by a standard one zone synchrotron self Compton model. We also performed a study on the source classification. While the optical and X-ray data taken during our campaign show typical characteristics of an HBL, we suggest, based on archival data, that 1ES 1011+496 is actually a borderline case between intermediate and high synchrotron peak frequency BL Lac objects.Comment: 13 pages, accepted for publication in MNRA

    Probing the very-high-energy gamma-ray spectral curvature in the blazar PG 1553+113 with the MAGIC telescopes

    Get PDF
    PG 1553+113 is a very-high-energy (VHE, E>100GeVE>100\,\mathrm{GeV}) γ\gamma-ray emitter classified as a BL Lac object. Its redshift is constrained by intergalactic absorption lines in the range 0.4<z<0.580.4<z<0.58. The MAGIC telescopes have monitored the source's activity since 2005. In early 2012, PG 1553+113 was found in a high-state, and later, in April of the same year, the source reached its highest VHE flux state detected so far. Simultaneous observations carried out in X-rays during 2012 April show similar flaring behaviour. In contrast, the γ\gamma-ray flux at E<100GeVE<100\,\mathrm{GeV} observed by Fermi-LAT is compatible with steady emission. In this paper, a detailed study of the flaring state is presented. The VHE spectrum shows clear curvature, being well fitted either by a power law with an exponential cut-off or by a log-parabola. A simple power-law fit hypothesis for the observed shape of the PG 1553+113 VHE γ\gamma-ray spectrum is rejected with a high significance (fit probability P=2.6 ×106\times 10^{-6}). The observed curvature is compatible with the extragalactic background light (EBL) imprint predicted by current generation EBL models assuming a redshift z0.4z\sim0.4. New constraints on the redshift are derived from the VHE spectrum. These constraints are compatible with previous limits and suggest that the source is most likely located around the optical lower limit, z=0.4z=0.4, based on the detection of Lyα\alpha absorption. Finally, we find that the synchrotron self-Compton (SSC) model gives a satisfactory description of the observed multi-wavelength spectral energy distribution during the flare.Comment: 13 pages, 7 figures, accepted for publication in MNRA

    Spanish cohort of VEXAS syndrome : clinical manifestations, outcome of treatments and novel evidences about UBA1 mosaicism

    Get PDF
    The vacuoles, E1-enzyme, X linked, autoinflammatory and somatic (VEXAS) syndrome is an adult-onset autoinflammatory disease (AID) due to postzygotic UBA1 variants. To investigate the presence of VEXAS syndrome among patients with adult-onset undiagnosed AID. Additional studies evaluated the mosaicism distribution and the circulating cytokines. Gene analyses were performed by both Sanger and amplicon-based deep sequencing. Patients' data were collected from their medical charts. Cytokines were quantified by Luminex. Genetic analyses of enrolled patients (n=42) identified 30 patients carrying UBA1 pathogenic variants, with frequencies compatible for postzygotic variants. All patients were male individuals who presented with a late-onset disease (mean 67.5 years; median 67.0 years) characterised by cutaneous lesions (90%), fever (66.7%), pulmonary manifestations (66.7%) and arthritis (53.3%). Macrocytic anaemia and increased erythrocyte sedimentation rate and ferritin were the most relevant analytical abnormalities. Glucocorticoids ameliorated the inflammatory manifestations, but most patients became glucocorticoid-dependent. Positive responses were obtained when targeting the haematopoietic component of the disease with either decitabine or allogeneic haematopoietic stem cell transplantation. Additional analyses detected the UBA1 variants in both haematopoietic and non-haematopoietic tissues. Finally, analysis of circulating cytokines did not identify inflammatory mediators of the disease. Thirty patients with adult-onset AID were definitively diagnosed with VEXAS syndrome through genetic analyses. Despite minor interindividual differences, their main characteristics were in concordance with previous reports. We detected for the first time the UBA1 mosaicism in non-haematopoietic tissue, which questions the previous concept of myeloid-restricted mosaicism and may have conceptual consequences for the disease mechanisms
    corecore