420 research outputs found

    Synthesis and Antimicrobial Activity of a Silver-Hydroxyapatite Nanocomposite

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    A silver-hydroxyapatite nanocomposite has been obtained by a colloidal chemical route and subsequent reduction process in H2/Ar atmosphere at C. This material has been characterized by TEM, XRD, and UV-Visible spectroscopy, showing the silver nanoparticles (65 nm) supported onto the HA particles (130 nm) surface without a high degree of agglomeration. The bactericidal effect against common Gram-positive and Gram-negative bacteria has been also investigated. The results indicated a high antimicrobial activity for Staphylococcus aureus, Pneumococcus and Escherichia coli, so this material can be a promising antimicrobial biomaterial for implant and reconstructive surgery applications.This work was supported by Bioker Research S.L. and by the Spanish Ministry of Education and Science under Project CENIT-INTELIMPLANT (ref.: 20071210). M. Díaz has been supported by Spanish Ministry of Education and Science and CSIC under I3P Program financed by European Social FundS

    Turning Emergency Plans into Executable Artifacts

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    ISBN: 978-0-692-21194-6 Available under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0) LicenseInternational audienceOn the way to the improvement of Emergency Plans, we show how a structured specification of the response procedures allows transforming static plans into dynamic, executable entities that can drive the way different actors participate in crisis responses. Additionally, the execution of plans requires the definition of information access mechanisms allowing execution engines to provide an actor with all the information resources he or she needs to accomplish a response task. We describe work in progress to improve the SAGA's Plan definition Module and Plan Execution Engine to support information-rich plan execution

    Experimental and theoretical study of rotationally inelastic diffraction of H_2(D_2) from methyl-terminated Si(111)

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    Fundamental details concerning the interaction between H_2 and CH_3–Si(111) have been elucidated by the combination of diffractive scattering experiments and electronic structure and scattering calculations. Rotationally inelastic diffraction (RID) of H_2 and D_2 from this model hydrocarbon-decorated semiconductor interface has been confirmed for the first time via both time-of-flight and diffraction measurements, with modest j = 0 → 2 RID intensities for H_2 compared to the strong RID features observed for D_2 over a large range of kinematic scattering conditions along two high-symmetry azimuthal directions. The Debye-Waller model was applied to the thermal attenuation of diffraction peaks, allowing for precise determination of the RID probabilities by accounting for incoherent motion of the CH_3–Si(111) surface atoms. The probabilities of rotationally inelastic diffraction of H_2 and D_2 have been quantitatively evaluated as a function of beam energy and scattering angle, and have been compared with complementary electronic structure and scattering calculations to provide insight into the interaction potential between H_2 (D_2) and hence the surface charge density distribution. Specifically, a six-dimensional potential energy surface (PES), describing the electronic structure of the H_2(D_2)/CH_3−Si(111) system, has been computed based on interpolation of density functional theory energies. Quantum and classical dynamics simulations have allowed for an assessment of the accuracy of the PES, and subsequently for identification of the features of the PES that serve as classical turning points. A close scrutiny of the PES reveals the highly anisotropic character of the interaction potential at these turning points. This combination of experiment and theory provides new and important details about the interaction of H_2 with a hybrid organic-semiconductor interface, which can be used to further investigate energy flow in technologically relevant systems

    Aircraft icing: in-cloud measurements and sensitivity to physical parameterizations

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    The prediction of supercooled cloud drops in the atmosphere is a basic tool for aviation safety, owing to their contact with and instant freezing on sensitive locations of the aircraft. One of the main disadvantages for predicting atmospheric icing conditions is the acquisition of observational data. In this study, we used in‐cloud microphysics measurements taken during 10 flights of a C‐212 research aircraft under winter conditions, during which we encountered 37 regions containing supercooled liquid water. To investigate the capability of the Weather Research and Forecasting model to detect regions containing supercooled cloud drops, we propose a multiphysics ensemble approach. We used four microphysics and two planetary boundary layer schemes. The Morrison parameterization yielded superior results, whereas the planetary boundary layer schemes were essential in evaluating the presence of liquid water content. The Goddard microphysics scheme best detected the presence of ice water content but tended to underestimate liquid water content

    Banco de La Concepción: A new Natura 2000 Marine Site off Canary Islands

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    The main objective of the LIFE+ INDEMARES project is to contribute to the protection and sustainable use of the biodiversity in the Spanish seas through the identification of valuable areas for the Natura 2000 Network. The Spanish Institute of Oceanography (IEO) has been in charge of implementing scientific surveys to map sensitive habitats of seven of the ten INDEMARES areas, and to determine the fisheries footprint over these areas. Banco de La Concepci´on is one of the areas chosen to be depicted in the frame of INDEMARES project. Located at 71 km to the NE of Lanzarote, at the coordinates 29º 55’ Latitude N and 12º 45’ Longitude W, Banco de la Concepci´on raises from 2,541 m up to its summit at 170 m deep. The biological richness of Banco de la Concepci´on is very influenced by the deep water up-welling phenomena, which create a high productivity, attracting a multitude of pelagic species, such as cetaceans, turtles, sharks, and tunas looking for food. In its vicinity, fishery resources such as goraz, anglerfish, and hakes, are abundant, and a rich invertebrate fauna cohabits in their bottoms. Banco de la Concepci´on is a traditional fishing area of oceanic pelagic species, and very good to catch demersal fish; it is highly visited by Galician and Portuguese drifters and long liners that fish in Mauritania, and mainly by the Andalusian longliners. In general, its main impacts are related to uncontrolled fishing pressure. The available information on the anthropogenic impact of the area was scarce, and its level of research was very poor as well, before INDEMARES project. Methodology approach complies with a multidisciplinary perspective, having described the area from geological, oceanographic, biological and fisheries points of view. Several surveys have taken place since 2009 to 2013 at Banco de La Concepci´on waters. Traps, longlines, beam trawls, benthic dredges and box corers have been used to sample benthic fauna. These last two, plus EM 3002 multibeam echosounder, PS 18 parametric sub bottom profiler, EA600 monobeam sounder, Seapath 200 positioning sensor and SV Plus sound velocity calibration sensor were used to make a geophysical study which provides a range of environmental factors. CTD was used to depict physical conditions of the water column. Finally, Remote Operated Vehicle Liropus 2000 and different photogrammetric tugged sleds were used to make a great effort of visual sampling. Data from VMS (Vessel Monitoring System) were used, combined with interviews to users (fishers), to describe the fishery uses in the area. Results from all this field work provide enough information for the administrations to establish a new Natura 2000 area, trying to reconcile protection of biodiversity and artisanal local economic activities. This establishment should take place at the end of a process of public consultation to stakeholders which is taking place in the present and which will help to shape the future Management Plan which will give details about permitted and prohibited uses

    Sensitive Habitats and fishing footprint off Canary Islands seamounts Amanay and El Banquete

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    The main objective of the LIFE+ INDEMARES project is to contribute to the protection and sustainable use of the biodiversity in the Spanish seas through the identification of valuable areas for the Natura 2000 Network. The Spanish Institute of Oceanography (IEO) has been in charge of implementing scientific surveys to map sensitive habitats of seven of the ten INDEMARES areas, and to determine the fisheries footprint over these areas. Sur y Oriente de Fuerteventura y Lanzarote is one of the areas chosen to be depicted in the frame of INDEMARES project, although the study about benthic habitats and fishery footprint carried by IEO has restricted to Amanay and El Banquete Seamounts. El Banquete really is the extension of southern continental shelf while Amanay seamount is located at 25 km from Jand´ıa Lighthouse (S of Fuerteventura) and 55 km from Las Palmas de Gran Canaria, at the coordinates 28º 07’ Latitude N and 14º 44’ LongitudeW, both volcanic buildings raise from more than 2,000 m up to their summits at 25-30 m deep, separated by a 1.500 m deep channel. The biological richness of Amanay and El Banquete seamounts is very influenced by the deep water up-welling phenomena, which create a high productivity, attracting a multitude of pelagic species, such as cetaceans, turtles, sharks, and tunas looking for food. There is also a high influence from Saharian up-welling. Both the seamounts tops and their vicinities are often visited by a large artisanal local fishing fleet which profits of their fishery resources; also a rich invertebrate fauna cohabits in their bottoms. In general, its main impacts are related to uncontrolled fishing pressure, and maritime navigation. The available information on the anthropogenic impact of the area was scarce, and its level of research was very poor as well, before INDEMARES project. Methodology approach complies with a multidisciplinary perspective, having described the area from geological, oceanographic, biological and fisheries points of view. Several surveys have taken place since 2009 to 2013 at Amanay and El Banquete waters. Traps, longlines, beam trawls, benthic dredges and box corers have been used to sample benthic fauna. These last two, plus EM 3002 multibeam echosounder, PS 18 parametric sub bottom profiler, EA600 monobeam sounder, Seapath 200 positioning sensor and SV Plus sound velocity calibration sensor were used to make a geophysical study which provides a range of environmental factors. CTD was used to depict physical conditions of the water column. Finally, different photogrammetric tugged sleds were used to make a great effort of visual sampling. Data from VMS (Vessel Monitoring System) were used, combined with interviews to users (fishers), landing samplings and scientific observation onboard, to describe the fishery uses in the area

    Observation of the black widow B1957+20 millisecond pulsar binary system with the MAGIC telescopes

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    Spontaneous breaking of Lorentz symmetry at energies on the order of the Planck energy or lower is predicted by many quantum gravity theories, implying non-trivial dispersion relations for the photon in vacuum. Consequently, gamma-rays of different energies, emitted simultaneously from astrophysical sources, could accumulate measurable differences in their time of flight until they reach the Earth. Such tests have been carried out in the past using fast variations of gamma-ray flux from pulsars, and more recently from active galactic nuclei and gamma-ray bursts. We present new constraints studying the gamma-ray emission of the galactic Crab Pulsar, recently observed up to TeV energies by the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) collaboration. A profile likelihood analysis of pulsar events reconstructed for energies above 400. GeV finds no significant variation in arrival time as their energy increases.. Ninety-five percent CL limits are obtained on the effective Lorentz invariance violating energy scale at the level of E-QG1 > 5.5 x 10(17) GeV (4.5 x 10(17) GeV) for a linear, and E-QG2 > 5.9 x 10(10) GeV (5.3 x 10(10) GeV) for a quadratic scenario, for the subluminal and the superluminal cases, respectively. A substantial part of this study is dedicated to calibration of the test statistic, with respect to bias and coverage properties. Moreover, the limits take into account systematic uncertainties, which are found to worsen the statistical limits by about 36%-42%. Our constraints would have been much more stringent if the intrinsic pulse shape of the pulsar between 200 GeV and 400 GeV was understood in sufficient detail and allowed inclusion of events well below 400 GeV

    Constraining Lorentz Invariance Violation Using the Crab Pulsar Emission Observed up to TeV Energies by MAGIC

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    Spontaneous breaking of Lorentz symmetry at energies on the order of the Planck energy or lower is predicted by many quantum gravity theories, implying non-trivial dispersion relations for the photon in vacuum. Consequently, gamma-rays of different energies, emitted simultaneously from astrophysical sources, could accumulate measurable differences in their time of flight until they reach the Earth. Such tests have been carried out in the past using fast variations of gamma-ray flux from pulsars, and more recently from active galactic nuclei and gamma-ray bursts. We present new constraints studying the gamma-ray emission of the galactic Crab Pulsar, recently observed up to TeV energies by the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) collaboration. A profile likelihood analysis of pulsar events reconstructed for energies above 400. GeV finds no significant variation in arrival time as their energy increases.. Ninety-five percent CL limits are obtained on the effective Lorentz invariance violating energy scale at the level of E-QG1 > 5.5 x 10(17) GeV (4.5 x 10(17) GeV) for a linear, and E-QG2 > 5.9 x 10(10) GeV (5.3 x 10(10) GeV) for a quadratic scenario, for the subluminal and the superluminal cases, respectively. A substantial part of this study is dedicated to calibration of the test statistic, with respect to bias and coverage properties. Moreover, the limits take into account systematic uncertainties, which are found to worsen the statistical limits by about 36%-42%. Our constraints would have been much more stringent if the intrinsic pulse shape of the pulsar between 200 GeV and 400 GeV was understood in sufficient detail and allowed inclusion of events well below 400 GeV

    Calidad Acústica de Aulas Universitarias: Análisis y Evaluación de Parámetros Acústicos de Recintos

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    En nuestro país, por lo general, las aulas han sido construidas sin considerar criterios acústicos, generando ambientes inadecuados para el proceso de enseñanza-aprendizaje. Ésta situación, interfiere tanto en el desempeño académico de los alumnos, como en la salud de los docentes. En este trabajo se analizan los principales factores acústicos intervinientes en dicho proceso, tales como: geometría y materiales del recinto, ruido de fondo, tiempos de reverberación y relación señal/ruido. Los resultados evidencian que una cantidad significativa de aulas utilizadas en el dictado de carreras de grado no presentan condiciones adecuadas para el desarrollo del proceso de enseñanza-aprendizaje. Los resultados presentados se obtuvieron en el marco del PID UTN 1658: “Estudio de características principales del campo sonoro en aulas y auditorios
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