103 research outputs found

    Dispersive calculation of complex Regge trajectories for the lightest f_2 resonances and the K^∗(892)

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    We apply a recently developed dispersive formalism to calculate the Regge trajectories of the f_2(1270), f´_ 2(1525) and K^∗(892) mesons. Trajectories are calculated, not fitted to a family of resonances. Assuming that these resonances can be treated in the elastic approximation, the only input are the pole position and residue of a resonance. In all three cases, the predicted Regge trajectories are almost real and linear, with slopes in agreement with the universal value of order 1 GeV_(−2). We also show how these results barely change when considering more than two subtractions in the dispersive formalism

    Data Sources as a Driver for Market‑Oriented Tourism Organizations: a Bibliometric Perspective

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    This paper presents a conceptual framework that accurately represents the current and future perspectives of data-driven companies in tourism by means of an analysis of the data sources used in the data-driven tourism research literature, as well as the research topics to which they are applied. For this purpose, a bibliometric analysis of data-driven tourism research is carried out. The framework of the study is all tourism-related publications whose research was based on data sources during the period 1982–2020. The results show some of the basic bibliometric performance indicators and the maps of science. The main themes of research interest are identified, and the conceptual evolution is obtained based on these maps. Three major thematic areas are identified: tourism research topics, information sources, and data analysis techniques. Based on these three thematic areas, the conceptual model of data architecture and processes of a data-driven organization in the tourism sector are obtained. An additional qualitative analysis of the three thematic areas is performedCRUE-CSIC agreement with Springer Natur

    Iniciación a la investigación en un laboratorio integrado de química

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    El reto planteado por la Convergencia al Espacio Europeo en la Educación Superior (EEES) supone una oportunidad para la reflexión y la puesta en marcha de iniciativas de mejora de la calidad en el ámbito de la docencia universitaria. Aprovechando este impulso, se propone un Proyecto de Innovación Docente en la asignatura troncal de “Experimentación en Química Inorgánica” del tercer curso de la Licenciatura en Química de la Universidad de Jaén.El trabajo presentado recoge la actuación en un laboratorio integrado de Química en el que se desarrollará el proceso de aplicación de los conocimientos adquiridos por los alumnos en las diversas asignaturas cursadas sobre sólidos inorgánicos, caracterización de sólidos adsorbentes, estudio de superficies, procesos de adsorción, técnicas quimiométricas y valorización de subproductos y concienciación medioambiental

    Estudio comparativo del consúmo crónico de vino tinto sobre la expresión y la actividad del sitocromo P450 en hígado y riñón de rata

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    ResumenEl metabolismo del etanol involucra la participación de isoenzimas del citocromo P450 (CYP), principalmente con la contribución de la isoenzima 2E1(CYP 2E1), cuya actividad es inducida por la exposición crónica al alcohol. El metabolismo etílico está relacionado con la producción de especies reactivas de oxígeno(ROS), responsables de la generación de estrés oxidativo.[Huerta PA, Henríquez PA, Castillo RL, Carasco RA, Orellana M, Rodrigo RA. Estudio comparativo del consúmo crónico de vino tinto sobre la expresión y la actividad del sitocromo P450 en hígado y riñón de rata. MedUNAB 2003; 6(16):4-9].Palabras clave: Citocromo P450 etanol, estrés oxidativo, riñon de la rata, hígado de la rata

    Efecto antagónico del consumo crónico de vino tinto y etanol sobre la actividad de la (Na+K)ATPasa renal

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    ResumenEl consumo crónico de etanol aumenta la actividad de (Na+K)ATPasa en diferentes tipos celulares, a travez de un mecanismo mediado por especies reactivas de oxígeno (EROs). el consumo moderado de vino tinto puede aumentar las defensas antioxidantes ya que sus componentes no alcohólicos actúan como atrapadores de EROs, quelantes de metales y moduladores enzimáticos.[Castillo RL, Carasco RA, House M, Huerta PA, Henríquez PA, Rodrigo RA. Efecto antagónico del consumo crónico de vino tinto y etanol sobre la actividad de la (Na+K)ATPasa renal. MedUNAB 2003; 6(16):10-14].Palabras clave; etanol, (Na+K)ATPasa, riñon, vino, antioxidantes

    BETs: Propellant less de orbiting of space debris by bare electrodynamic tethers

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    As a fundamental contribution to limiting the increase of debris in the Space environment, a three-year project started on 1 November 2010 financed by the European Commission under the FP-7 Space Programme. It aims at developing a universal system to be carried on board future satellites launched into low Earth orbit (LEO), to allow de-orbiting at end of life. The operational system involves a conductive tape-tether left bare of insulation to establish anodic contact with the ambient plasma as a giant Langmuir probe. The project will size the three disparate dimensions of a tape for a selected de-orbit mission and determine scaling laws to allow system design for a general mission. It will implement control laws to restrain tether dynamics in/off the orbital plane; and will carry out plasma chamber measurements and numerical simulations of tether-plasma interaction. The project also involves the design and manufacturing of subsystems: electron-ejecting plasma contactors, an electric control and power module, interface elements, tether and deployment mechanisms, tether tape/end-mass as well as current collection plus free-fall, and hypervelocity impact tests

    Selenium and impaired physical function in US and Spanish older adults

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    Background: Selenium (Se) is a trace element with a narrow safety margin. Objectives: To evaluate the cross-sectional and longitudinal dose-response association between Se exposure and measures of impaired physical function and disability in older adults. Design: NHANES 2011–2014 cross-sectional (US, n = 1733, age ≥60 years) and Seniors-ENRICA-2 2017–2019 cross-sectional and longitudinal (Spain, n = 2548 and 1741, respectively, age ≥65 years) data were analyzed. Whole blood and serum Se levels were measured using inductively coupled plasma-mass spectrometry. Lowerextremity performance was assessed with the Short Physical Performance Battery, and muscle weakness with a dynamometer. Incident mobility and agility limitations, and disability in instrumental activities of daily living (IADL) were ascertained with standardized questionnaires. Analyses were adjusted for relevant confounders, including physical activity. Results across studies were pooled using random-effects meta-analysis. Results: Meta-analyzed odds ratios (95% confidence interval) per log2 increase in whole blood Se were 0.54 (0.32; 0.76) for weakness, 0.59 (0.34; 0.83) for impaired lower-extremity performance, 0.48 (0.31; 0.68) for mobility limitations, 0.71 (0.45; 0.97) for agility limitations, and 0.34 (0.12; 0.56) for disability in at least one IADL. Analyses for serum Se in NHANES showed similar results. Findings suggest the inverse association with grip strength is progressive below 140 μg/L (p-value for non-linear trend in the Seniors-ENRICA-2 study = 0.13), and above 140 μg/L (p-value for non-linear trend in NHANES = 0.11). In the Seniors-ENRICA-2 cohort, with a 2.2 year follow-up period, a doubling in baseline Se levels were associated with a lower incidence of weakness [odds ratio (95% confidence interval): 0.45 (0.22; 0.91)], impaired lower-extremity performance [0.63 (0.32; 1.23)], mobility [0.43 (0.21; 0.91)] and agility [0.38 (0.18; 0.78)] limitations. Discussion: In US and Spanish older adults, Se concentrations were inversely associated with physical function limitations. Further studies are needed to elucidate underlying mechanisms.Instituto de Salud Carlos III European Commission PI18/287 16/609State Secretary of R + D + I PID2019-108973RB-C21/C22European Social Fund (ESF) European Commissio

    Frequency of breast cancer with hereditary risk features in Spain: Analysis from GEICAM “El Álamo III” retrospective study

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    Purpose: To determine the frequency of breast cancer (BC) patients with hereditary risk features in a wide retrospective cohort of patients in Spain. Methods: a retrospective analysis was conducted from 10, 638 BC patients diagnosed between 1998 and 2001 in the GEICAM registry “El Álamo III”, dividing them into four groups according to modified ESMO and SEOM hereditary cancer risk criteria: Sporadic breast cancer group (R0); Individual risk group (IR); Familial risk group (FR); Individual and familial risk group (IFR) with both individual and familial risk criteria. Results: 7, 641 patients were evaluable. Of them, 2, 252 patients (29.5%) had at least one hereditary risk criteria, being subclassified in: FR 1.105 (14.5%), IR 970 (12.7%), IFR 177 (2.3%). There was a higher frequency of newly diagnosed metastatic patients in the IR group (5.1% vs 3.2%, p = 0.02). In contrast, in RO were lower proportion of big tumors (> T2) (43.8% vs 47.4%, p = 0.023), nodal involvement (43.4% vs 48.1%, p = 0.004) and lower histological grades (20.9% G3 for the R0 vs 29.8%) when compared to patients with any risk criteria. Conclusions: Almost three out of ten BC patients have at least one hereditary risk cancer feature that would warrant further genetic counseling. Patients with hereditary cancer risk seems to be diagnosed with worse prognosis factors

    Propellantless de orbiting of space debris by bare electrodynamic tethers

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    A 3-year Project started on November 1 2010, financed by the European Commision within the FP-7 Space Program, and aimed at developing an efficient de-orbit system that could be carried on board by future spacecraft launched into LEO, will be presented. The operational system will deploy a thin uninsulated tape-tether to collect electrons as a giant Langmuir probe, using no propellant/no power supply, and generating power on board. This project will involve free-fall tests, and laboratory hypervelocity-impact and tether-current tests, and design/Manufacturing of subsystems: interface elements, electric control and driving module, electron-ejecting plasma contactor, tether-deployment mechanism/end-mass, and tape samples. Preliminary results to be presented involve: i) devising criteria for sizing the three disparate tape dimensions, affecting mass, resistance, current-collection, magnetic self-field, and survivability against debris itself; ii) assessing the dynamical relevance of tether parameters in implementing control laws to limit oscillations in /off the orbital plane, where passive stability may be marginal; iii) deriving a law for bare-tape current from numerical simulations and chamber tests, taking into account ambient magnetic field, ion ram motion, and adiabatic electron trapping; iv) determining requirements on a year-dormant hollow cathode under long times/broad emission-range operation, and trading-off against use of electron thermal emission; v) determining requirements on magnetic components and power semiconductors for a control module that faces high voltage/power operation under mass/volume limitations; vi) assessing strategies to passively deploy a wide conductive tape that needs no retrieval, while avoiding jamming and ending at minimum libration; vii) evaluating the tape structure as regards conductive and dielectric materials, both lengthwise and in its cross-section, in particular to prevent arcing in triple-point junctions
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