385 research outputs found

    H^s versus C^0-weighted minimizers

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    We study a class of semi-linear problems involving the fractional Laplacian under subcritical or critical growth assumptions. We prove that, for the corresponding functional, local minimizers with respect to a C^0-topology weighted with a suitable power of the distance from the boundary are actually local minimizers in the natural H^s-topology.Comment: 15 page

    Ability of trees for microclimatic regulation the San Ginés de la Jara park (Cartagena)

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    [SPA] El presente trabajo tiene por objetivo demostrar la capacidad del arbolado de producir sombra y sus efectos sobre la generación de confort térmico a los usuarios del parque urbano de San Ginés de la Jara. El arbolado puede modificar el microclima local de manera sensible mediante la generación de sombra, pero esta capacidad depende de las características propias de cada especie (tamaño, forma y frondosidad) y de su gestión. Se realizaron mediciones sobre el arbolado y las sombras proyectadas mediante fotografía y un sistema de información geográfica (SIG) con el que se determinó el área total sombreada por el arbolado (Obra derivada de LiDAR-PNOA 2016 CC-BY 4.0 scne.es). Adicionalmente, se realizó un estudio de capacidad de generación de confort térmico mediante termografías y el cálculo de los índices térmicos PET (ºC) y PT (ºC). [ENG] The present work aims to demonstrate the ability of urban forest trees for shading and its effects on the generation of thermal comfort for users of the urban park of San Ginés de la Jara. Trees can modify the local microclimate in a significant way by generating shade, but this ability depends on the characteristics of each species (size, shape, and leafiness) and its management. To study it, different measurements were made on the trees and their projected shadows by photography and a geographic information system (GIS) which led determine the total area shaded by the trees (work derived from LiDAR-PNOA 2016 CC-BY 4.0 scne.es). Additionally, a thermal comfort generation capacity study was carried out using thermography and the calculation of the thermal indices PET (ºC) and PT (ºC).Este trabajo ha sido posible gracias al apoyo financiero y técnico de la empresa Actúa Servicios y Medioambiente S.L

    Neutronic analysis of a dual He/LiPb coolant breeding blanket for DEMO

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    A conceptual design of a DEMO fusion reactor is being developed under the Spanish Breeding Blanket Technology Programme: TECNO_FUS based on a He/LiPb dual coolant blanket as reference design option. The following issues have been analyzed to address the demonstration of the neutronic reliability of this conceptual blanket design: power amplification capacity of the blanket, tritium breeding capability for fuel self-sufficiency, power deposition due to nuclear heating in superconducting coils and material damage (dpa, gas production) to estimate the operational life of the steel-made structural components in the blanket and vacuum vessel (VV). In order to optimize the shielding of the coils different combinations of water and steel have been considered for the gap of the VV. The used neutron source is based on an axi-symmetric 2D fusion reaction profile for the given plasma equilibrium configuration. MCNPX has been used for transport calculations and ACAB has been used to handle gas production and damage energy cross sections

    Gamma Ray Bursts as Probes of Quantum Gravity

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    Gamma ray bursts (GRBs) are short and intense pulses of γ\gamma-rays arriving from random directions in the sky. Several years ago Amelino-Camelia et al. pointed out that a comparison of time of arrival of photons at different energies from a GRB could be used to measure (or obtain a limit on) possible deviations from a constant speed of light at high photons energies. I review here our current understanding of GRBs and reconsider the possibility of performing these observations.Comment: Lectures given at the 40th winter school of theretical physics: Quantum Gravity and Phenomenology, Feb. 2004 Polan

    Desarrollo y evaluación de la competencia gestión de la información en titulaciones técnicas: estudio de casos

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    [SPA]Hoy en día ya no es suficiente contar con las habilidades básicas de alfabetización que teníamos antes, como saber leer o escribir. Hoy incluso no basta con saber utilizar el ordenador, el teléfono u otros medios de comunicación. Se hace necesario estar alfabetizado informacionalmente (ALFIN). Esto implica no solo saber que la información existe, sino saber como encontrarla, como utilizarla, como manipularla, como sacar provecho de ella. Así se manifestaba en 2003 Horton especialista en derecho al acceso a la información pública. Un estudiante o un profesor son alfabetos informacionales porque saben cuando y porqué necesitan información, dónde encontrarla y como valorarla, utilizarla y comunicarla de manera ética. En este trabajo se presenta el estudio de tres casos llevados a cabo con estudiantes de diversas escuelas de ingeniería en la Universidad Politécnica de Cartagena. En ellos se muestra un procedimiento sencillo para incluir en la metodología docente de cualquier área de conocimiento la formación en gestión de la información, esto es, en el acceso, recuperación, análisis, evaluación y uso de la información. Asimismo se presenta una rúbrica que permite evaluar los logros adquiridos por los estudiantes que no son sino una forma de evaluar dicha habilidad. [ENG]Nowadays, the ability to read or write is not considered anymore as a basic standard for literacy. Neither the capability to use a computer, a telephone or any other communication device is enough in a professional context. Conversely, the informational literacy has become a professional skill of utmost importance. This means that the graduate must know not only that a certain information exists, but also it's necessary to know how to find it, use it, manipulate it and get benefit from it. A student or a lecturer are skilled on informational literacy when they identify why they do need the information, and they can find it, value, use and communicate it in an ethical manner. In this work, tree different classroom methodologies employed in several Departments and Technical University of Cartagena (UPCT) are presented. The activities to develop the information literacy of the students are thoroughly explained. A rubric for the evaluation of this competency is presented.Campus Mare Nostrum, Universidad Politécnica de Cartagena, Universidad de Murcia, Región de Murci

    All‐optical three‐input logic minterms generation using semiconductor optical amplifier‐based Sagnac interferometer

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    All-optical three-input logic minterms are generated at 42 Gbit/s with a Sagnac interferometer by using cross-phase modulation in a semiconductor optical amplifier. To the best of the author's knowledge, this is the first time that high-speed logic operations with more than two inputs have been experimentally demonstrated in a Sagnac interferometer. Correct and clear temporal waveforms are successfully observed. Bit error ratios and optical signal-to-noise ratios are measured to demonstrate the effectiveness of the method. As the basic units of combinational logic operations, logic minterms are promising candidates to construct reconfigurable and programmable logic functions

    Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

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    Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius AA. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter
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