123 research outputs found

    Caracterización de la fragilización por hidrógeno mediante la aplicación de la técnica de escalones incrementales al ensayo small punch

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    En este trabajo se aplica al ensayo Small Punch, la técnica de carga por escalones para medir el umbral de fragilización en aceros definida en la noma ASTM Fl624. Para ello se utiliza un acero de media resistencia, simulando el ambiente fragilizante mediante una polarización catódica a través de la aplicación de una corriente de 5mA/cm2 en una solución ácida principalmente 1 N de H2SÜ4 en H2O. En una tarea paralela se llevaron a cabo ensayos normalizados sobre probetas de tracción según la norma ASTM Fl624, observándose las mismas tendencias en ambos casos, lo que valida la metodología propuesta. Para adaptar la citada norma al ensayo Small Punch se modificó la duración de los escalones de carga, proponiendo su reducción en base a las dimensiones de las probetas Small Punch, así como la velocidad de punzonado que tiene lugar en este tipo de escenarios ambientales según la bibliografía. Esta propuesta permite obtener un umbral de carga mediante el empleo de, al menos, 3 probetas en un tiempo total de una semana aproximadamente.Los autores desean agradecer la financiación prestada al Ministerio de Economía y Competitividad a través del proyecto de investigación MAT2014-58738-C3-3-R

    Olfactomedin‑like 2 A and B (OLFML2A and OLFML2B) expression profile in primates (human and baboon)

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    Background: The olfactomedin‑like domain (OLFML) is present in at least four families of proteins, including OLFML2A and OLFML2B, which are expressed in adult rat retina cells. However, no expression of their orthologous has ever been reported in human and baboon. Objective: The aim of this study was to investigate the expression of OLFML2A and OLFML2B in ocular tissues of baboons (Papio hamadryas) and humans, as a key to elucidate OLFML function in eye physiology. Methods: OLFML2A and OLFML2B cDNA detection in ocular tissues of these species was performed by RT‑PCR. The amplicons were cloned and sequenced, phylogenetically analyzed and their proteins products were confirmed by immunofluorescence assays. Results: OLFML2A and OLFML2B transcripts were found in human cornea, lens and retina and in baboon cornea, lens, iris and retina. The baboon OLFML2A and OLFML2B ORF sequences have 96% similarity with their human’s orthologous. OLFML2A and OLFML2B evolution fits the hypothesis of purifying selection. Phylogenetic analysis shows clear orthology in OLFML2A genes, while OLFML2B orthology is not clear. Conclusions: Expression of OLFML2A and OLFML2B in human and baboon ocular tissues, including their high simi‑ larity, make the baboon a powerful model to deduce the physiological and/or metabolic function of these proteins in the eye

    The new multi-frequency instrument (MFI2) for the QUIJOTE facility in Tenerife

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    The QUIJOTE (Q-U-I joint Tenerife) experiment combines the operation of two radio-telescopes and three instruments working in the microwave bands 10?20 GHz, 26-36 GHz and 35-47 GHz at the Teide Observatory, Tenerife, and has already been presented in previous SPIE meetings (Hoyland, R. J. et al, 2012; Rubiño-Martín et al., 2012). The Cosmology group at the IAC have designed a new upgrade to the MFI instrument in the band 10-20 GHz. The aim of the QUIJOTE telescopes is to characterise the polarised emission of the cosmic microwave background (CMB), as well as galactic and extra-galactic sources, at medium and large angular scales. This MFI2 will continue the survey at even higher sensitivity levels. The MFI2 project led by the Instituto de Astrofísica de Canarias (IAC) consists of five polarimeters, three of them operating in the sub-band 10?15 GHz, and two in the sub-band 15-20 GHz. The MFI2 instrument is expected to be a full two-three times more sensitive than the former MFI. The microwave complex correlator design has been replaced by a simple correlator design with a digital back-end based on the latest Xilinx FPGAs (ZCU111). During the first half of 2019 the manufacture of the new cryostat was completed and since then the opto-mechanical components have been designed and manufactured. It is expected that the cryogenic front-end will be completed by the end of 2022 along with the FPGA acquisition and observing system. This digital system has been employed to be more robust against stray ground-based and satellite interference, having a frequency resolution of 1 MHz.The MFI2 instrument is being developed by the Instituto de Astrofisica de Canarias (IAC), with an instrumental participation from the Universidad Politecnica de Cartagena (UPCT). Partial financial support is provided by the Spanish Ministry of Science and Innovation (MICINN), under the projects AYA2017-84185-P, IACA15-BE-3707, EQC2018-004918-P and the FEDER Agreement INSIDE-OOCC (ICTS-2019-03-IAC-12). We also acknowledge financial support of the Severo Ochoa Programs SEV-2015-0548 and CEX2019-000920-S

    Computing Activities at the Spanish Tier-1 and Tier-2s for the ATLAS experiment in the LHC Run 3 period and towards High Luminosity (HL-LHC)

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    The ATLAS Spanish Tier-1 and Tier-2s have more than 18 years of experience in the deployment and development of LHC computing components and their successful operation. The sites are actively participating in, and in some cases coordinating, R&D computing activities in the LHC Run 3 and developing the computing models needed in the HL-LHC period. In this contribution, we present details on the integration of some components, such as HPC computing resources to execute ATLAS simulation workflows; the development of new techniques to improve efficiency in a cost-effective way; and improvements in Data Organization, Management and Access through storage consolidations, the use of data caches, and improving experiment data catalogues, through contributions such as Event Index. The design and deployment of novel analysis facilities using GPUs together with CPUs and techniques like Machine Learning are also presented. ATLAS Tier-1 and Tier-2 sites in Spain, are, and will be, contributing to significant R&D in computing and evaluating different models for improving performance of computing and data storage capacity in the LHC High Luminosity era

    Libro Blanco Metodológico

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    Este documento es el Libro Blanco metodológico de la línea de investigación 'Digitalización de las Poblaciones del Sur Global' de la Universidad Loyola (Andalucía, España). Dentro de esta línea de investigación se desarrolló entre 2022 y 2024 un proyecto piloto en República Dominicana. Ese proyecto consistió en el estudio de la realidad de tres localizaciones dominicanas populares desde algunos puntos de vista de interés para la línea de investigación. Los datos obtenidos y algunas conclusiones a partir de ellos han sido publicadas en un extenso libro puesto a disposición del público en general. Pero además el proyecto en Repíblica Dominicana pretendía diseñar, probar y extraer conclusiones respecto a una metodología para el estudio de la digitalización de las poblaciones del Sur Global, que pudiera luego extenderse a otros países. Este Libro Blanco contiene los elementos estructurales básicos del proyecto realizado en República Dominicana, tanto teóricos como prácticos, y un recuento de los aprendizajes que el equipo investigador considera adecuado retener para tomar en cuenta para futuros proyectos dentro de la misma línea de investigación, en otros países de América Latina o de otros continentes. Esta es la versión 1.0 del Libro Blanco, que era preciso producir en el periodo asignado a la investigación. Ello explica que algunos aspectos no están todavía desarrollados en parte o en todo, particularmente lo relativo a artículos para journals, o una evaluación en más profundidad. Conforme haya progreso sustancial en estos aspectos, haremos públicas nuevas versiones del Libro Blanco.Financiado por AACID: Agencia Andaluza de Cooperación Internacional al Desarroll

    Search for tt¯ resonances in fully hadronic final states in pp collisions at √s = 13 TeV with the ATLAS detector

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    This paper presents a search for new heavy particles decaying into a pair of top quarks using 139 fb of proton-proton collision data recorded at a centre-of-mass energy of s = 13 TeV with the ATLAS detector at the Large Hadron Collider. The search is performed using events consistent with pair production of high-transverse-momentum top quarks and their subsequent decays into the fully hadronic final states. The analysis is optimized for resonances decaying into a tt¯ pair with mass above 1.4 TeV, exploiting a dedicated multivariate technique with jet substructure to identify hadronically decaying top quarks using large-radius jets and evaluating the background expectation from data. No significant deviation from the background prediction is observed. Limits are set on the production cross-section times branching fraction for the new Z′ boson in a topcolor-assisted-technicolor model. The Z′ boson masses below 3.9 and 4.7 TeV are excluded at 95% confidence level for the decay widths of 1% and 3%, respectively. [Figure not available: see fulltext.

    Constraints on Higgs boson properties using WW∗(→ eνμν) jj production in 36.1fb-1 of √s=13 TeV pp collisions with the ATLAS detector

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    This article presents the results of two studies of Higgs boson properties using the WW(→ eνμν) jj final state, based on a dataset corresponding to 36.1 fb of s=13 TeV proton–proton collisions recorded by the ATLAS experiment at the Large Hadron Collider. The first study targets Higgs boson production via gluon–gluon fusion and constrains the CP properties of the effective Higgs–gluon interaction. Using angular distributions and the overall rate, a value of tan (α) = 0.0 ± 0.4 (stat.) ± 0.3 (syst.) is obtained for the tangent of the mixing angle for CP-even and CP-odd contributions. The second study exploits the vector-boson fusion production mechanism to probe the Higgs boson couplings to longitudinally and transversely polarised W and Z bosons in both the production and the decay of the Higgs boson; these couplings have not been directly constrained previously. The polarisation-dependent coupling-strength scale factors are defined as the ratios of the measured polarisation-dependent coupling strengths to those predicted by the Standard Model, and are determined using rate and kinematic information to be aL=0.91-0.18+0.10(stat.)-0.17+0.09(syst.) and a= 1.2 ± 0.4 (stat.)-0.3+0.2(syst.). These coupling strengths are translated into pseudo-observables, resulting in κVV=0.91-0.18+0.10(stat.)-0.17+0.09(syst.) and ϵVV=0.13-0.20+0.28 (stat.)-0.10+0.08(syst.). All results are consistent with the Standard Model predictions

    Measurement of the nuclear modification factor for muons from charm and bottom hadrons in Pb+Pb collisions at 5.02 TeV with the ATLAS detector

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    Heavy-flavour hadron production provides information about the transport properties and microscopic structure of the quark–gluon plasma created in ultra-relativistic heavy-ion collisions. A measurement of the muons from semileptonic decays of charm and bottom hadrons produced in Pb+Pb and pp collisions at a nucleon–nucleon centre-of-mass energy of 5.02 TeV with the ATLAS detector at the Large Hadron Collider is presented. The Pb+Pb data were collected in 2015 and 2018 with sampled integrated luminosities of 208μb and 38μb, respectively, and pp data with a sampled integrated luminosity of 1.17pb were collected in 2017. Muons from heavy-flavour semileptonic decays are separated from the light-flavour hadronic background using the momentum imbalance between the inner detector and muon spectrometer measurements, and muons originating from charm and bottom decays are further separated via the muon track's transverse impact parameter. Differential yields in Pb+Pb collisions and differential cross sections in pp collisions for such muons are measured as a function of muon transverse momentum from 4 GeV to 30 GeV in the absolute pseudorapidity interval |η|<2. Nuclear modification factors for charm and bottom muons are presented as a function of muon transverse momentum in intervals of Pb+Pb collision centrality. The bottom muon results are the most precise measurement of b quark nuclear modification at low transverse momentum where reconstruction of B hadrons is challenging. The measured nuclear modification factors quantify a significant suppression of the yields of muons from decays of charm and bottom hadrons, with stronger effects for muons from charm hadron decays

    Constraints on Higgs boson production with large transverse momentum using H →b b ¯ decays in the ATLAS detector

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    This paper reports constraints on Higgs boson production with transverse momentum above 1 TeV. The analyzed data from proton-proton collisions at a center-of-mass energy of 13 TeV were recorded with the ATLAS detector at the Large Hadron Collider from 2015 to 2018 and correspond to an integrated luminosity of 136 fb-1. Higgs bosons decaying into bb¯ are reconstructed as single large-radius jets recoiling against a hadronic system and are identified by the experimental signature of two b-hadron decays. The experimental techniques are validated in the same kinematic regime using the Z→bb¯ process. The 95% confidence-level upper limit on the cross section for Higgs boson production with transverse momentum above 450 GeV is 115 fb, and above 1 TeV it is 9.6 fb. The Standard Model cross section predictions for a Higgs boson with a mass of 125 GeV in the same kinematic regions are 18.4 fb and 0.13 fb, respectively

    Measurement of Higgs boson decay into b-quarks in associated production with a top-quark pair in pp collisions at √s = 13 TeV with the ATLAS detector

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    The associated production of a Higgs boson and a top-quark pair is measured in events characterised by the presence of one or two electrons or muons. The Higgs boson decay into a b-quark pair is used. The analysed data, corresponding to an integrated luminosity of 139 fb, were collected in proton-proton collisions at the Large Hadron Collider between 2015 and 2018 at a centre-of-mass energy of s = 13 TeV. The measured signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model, is 0.35−0.34+0.36. This result is compatible with the Standard Model prediction and corresponds to an observed (expected) significance of 1.0 (2.7) standard deviations. The signal strength is also measured differentially in bins of the Higgs boson transverse momentum in the simplified template cross-section framework, including a bin for specially selected boosted Higgs bosons with transverse momentum above 300 GeV. [Figure not available: see fulltext.
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