20 research outputs found

    Asymmetric coupling between two quantum emitters

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    We study a prototypical model of two coupled two-level systems, where the competition between coherent and dissipative coupling gives rise to a rich phenomenology. In particular, we analyze the case of asymmetric coupling, as well as the limiting case of chiral (or one-way) coupling. We investigate various quantum optical properties of the system, including its steady-state populations, power spectrum, and second-order correlation functions, and outline the characteristic features which emerge in each quantity as one sweeps through the nontrivial landscape of effective complex couplings. Most importantly, we reveal instances of population trapping, unexpected spectral features, and strong emission correlations

    Risk-taking attitudes of people who seek health care: An exploratory approach through lottery games using generalized estimating equations

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    Background: The characterization of the risk-taking attitude of individuals may be useful for planning health care interventions. It has been attempted to study expressions of risk-taking attitude and evaluate characteristics of a standard lottery game in a population that seeks health care to elicit these attitudes. Methods: Multicentric cross-sectional study. Demographic and socioe-conomic characteristics, quality of life (EuroQol-5D), and health risk behaviors were collected from 662 users of 23 health centers selected by random sampling. Risk-taking attitude was evaluated by means of a self-evaluation scale and two lotteries games (L1 and L2; L2 included the possibility of economic losses). Generalized estimating equations (GEE) explicative models were used to evaluate the variability of risk-taking attitude. Results: Nineteen percent out of interviewed people (CI95%: 15.6-22.6%) expressed a high risk appetite, but only 10.0% (CI95% 7.0 to 13.0) were classified as risk-seeking by L2. It was found association between increased risk appetite and having a better perception of health status (0.110. CI95%: 0.007-0.212) or a higher income (0.010. CI95%: 0.017-0.123) or smoking status (0.059. CI95%: 0.004-0.114). Being Spanish was associated with lower risk appetite (-0.105. CI95%: -0.005 -0.205), as being over 65 (-0.031. CI95%:- 0.061- -0.001) or a woman (-0.038. CI95%:-0.064- -0.012). The intraclass correlation coefficient for self-evaluation scale was 0.511 (95% CI: 0.372 to 0.629), 0.571 (95% CI: 0.441-0.678) for L1 and 0.349 (95% CI: 0.186-0.493) for L2. Conclusions: People who seek health care express certain inclination to risk, but this feature is attenuated when methodologies involving losses are used. Risk appetite seems greater in young people, males, people with better health, or more income, and in immigrants. Lottery games such as the proposed ones are a simple and useful tool to estimate individuals'' inclination to risk

    Characterization of azo dyes on Pt and Pt/polyaniline/dispersed Pt electrodes

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    The electrochemical characterization of two organic dyes (amaranth and procion orange MX-2R) has been performed on Pt electrodes and Pt electrodes coated with polyaniline and dispersed Pt. Electrodes with different Pt loads have been synthesized and characterized obtaining that a load of 300 ¿g cm -2 was the optimum one. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) was employed to observe the distribution and morphology of the Pt nanoparticles. The electroactivity of the electrodes has also been characterized by means of scanning electrochemical microscopy (SECM). The chemical characterization of Pt dispersed Pani coated Pt electrodes (Pt-Pani-Pt) was performed by means of X-ray photoelectron spectroscopy (XPS). The electrochemical characterization of the dyes has been performed by means of cyclic voltammetry. Voltammograms have shown that the presence of the dyes diminishes characteristic Pt oxidation and reduction peaks. However, redox processes due to the dyes, appeared in the voltammograms. The different species responsible of these redox processes were generated in the vicinity of the electrode and were not adsorbed on the electrode surface since after stirring, the different redox processes disappeared. Characterization with different scan rates showed that redox processes of both dyes were controlled by diffusion. © 2012 Elsevier B.V.Authors thank to the Spanish Ministerio de Ciencia e Innovacion and European Union Funds (FEDER) (contracts CTM2010-18842-C02-02 and CTM2011-23583) and Universitat Politecnica de Valencia (Vicerrectorado de Investigacion PAID-06-10 contract 003-233) for the financial support. J. Molina is grateful to the Conselleria d'Educacio (Generalitat Valenciana) for the FPI fellowship. A.I. del Rio is grateful to the Spanish Ministerio de Ciencia y Tecnologia for the FPI fellowship.Molina Puerto, J.; Fernández Sáez, J.; Del Río García, AI.; Bonastre Cano, JA.; Cases Iborra, FJ. (2012). Characterization of azo dyes on Pt and Pt/polyaniline/dispersed Pt electrodes. Applied Surface Science. 258:6246-6256. doi:10.1016/j.apsusc.2012.02.150S6246625625

    Synthesis of Pt nanoparticles on electrochemically reduced graphene oxide by potentiostatic and alternate current methods

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    Reduced graphene oxide (RGO) has been synthesized on Pt wires by means of a potentiodynamic method between +0.6 V and -1.4'V for 20 scans. Cyclic voltammetry characterization of the coatings showed the typical capacitative behavior of graphene. Pt nanoparticles were synthesized on Pt-RGO electrodes by means of potentiostatic methods and a comparison between different synthesis potentials (-0.16, 0, +0.2 and +0.4 V) for the same synthesis charge (mC.cm(-2)) was established. The electrodes obtained were characterized in 0.5 M H2SO4 solution to observe the characteristic oxidation and reduction processes of the Pt surface. A 0.5 M H2SO4/0.5 M CH3OH solution was used to measure the catalytic properties of the deposits against methanol oxidation. The most appropriate potential to perform the synthesis was 0 V followed by -0.16 V and +0.2 V. The morphology of the coatings varied depending on the potential applied as observed by scanning electron microscopy. Alternate current methods were also used to synthesize Pt nanoparticles and compare the results with the traditional potentiostatic method. Different frequencies were used: 0.1, 1, 10, 100, 1000 and 10000 Hz. Alternate current synthesis is more efficient than traditional potentiostatic methods, obtaining more electroactive coatings with less effective synthesis time. (C) 2014 Elsevier Inc. All rights reserved.Authors wish to thank to the Spanish Ministerio de Ciencia e Innovacion (contract CTM2011-23583) and Universitat Politecnica de Valencia (Vicerrectorado de Investigacion PAID-06-10 contract 003-233) for the financial support. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship. A.I. del Rio is grateful to the Spanish Ministerio de Ciencia y Tecnologia for the FPI fellowship.Molina Puerto, J.; Fernández Sáez, J.; Del Río García, AI.; Bonastre Cano, JA.; Cases Iborra, FJ. (2014). Synthesis of Pt nanoparticles on electrochemically reduced graphene oxide by potentiostatic and alternate current methods. Materials Characterization. 89:56-68. https://doi.org/10.1016/j.matchar.2014.01.003S56688

    Epidemiological trends of HIV/HCV coinfection in Spain, 2015-2019

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    Altres ajuts: Spanish AIDS Research Network; European Funding for Regional Development (FEDER).Objectives: We assessed the prevalence of anti-hepatitis C virus (HCV) antibodies and active HCV infection (HCV-RNA-positive) in people living with HIV (PLWH) in Spain in 2019 and compared the results with those of four similar studies performed during 2015-2018. Methods: The study was performed in 41 centres. Sample size was estimated for an accuracy of 1%. Patients were selected by random sampling with proportional allocation. Results: The reference population comprised 41 973 PLWH, and the sample size was 1325. HCV serostatus was known in 1316 PLWH (99.3%), of whom 376 (28.6%) were HCV antibody (Ab)-positive (78.7% were prior injection drug users); 29 were HCV-RNA-positive (2.2%). Of the 29 HCV-RNA-positive PLWH, infection was chronic in 24, it was acute/recent in one, and it was of unknown duration in four. Cirrhosis was present in 71 (5.4%) PLWH overall, three (10.3%) HCV-RNA-positive patients and 68 (23.4%) of those who cleared HCV after anti-HCV therapy (p = 0.04). The prevalence of anti-HCV antibodies decreased steadily from 37.7% in 2015 to 28.6% in 2019 (p < 0.001); the prevalence of active HCV infection decreased from 22.1% in 2015 to 2.2% in 2019 (p < 0.001). Uptake of anti-HCV treatment increased from 53.9% in 2015 to 95.0% in 2019 (p < 0.001). Conclusions: In Spain, the prevalence of active HCV infection among PLWH at the end of 2019 was 2.2%, i.e. 90.0% lower than in 2015. Increased exposure to DAAs was probably the main reason for this sharp reduction. Despite the high coverage of treatment with direct-acting antiviral agents, HCV-related cirrhosis remains significant in this population

    Actas de las V Jornadas ScienCity 2022. Fomento de la Cultura Científica, Tecnológica y de Innovación en Ciudades Inteligentes

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    ScienCity es una actividad que viene siendo continuada desde 2018 con el objetivo de dar a conocer los conocimientos y tecnologías emergentes siendo investigados en las universidades, informar de experiencias, servicios e iniciativas puestas ya en marcha por instituciones y empresas, llegar hasta decisores políticos que podrían crear sinergias, incentivar la creación de ideas y posibilidades de desarrollo conjuntas, implicar y provocar la participación ciudadana, así como gestar una red internacional multidisciplinar de investigadores que garantice la continuación de futuras ediciones. En 2022 se recibieron un total de 48 trabajos repartidos en 25 ponencias y 24 pósteres pertenecientes a 98 autores de 14 instituciones distintas de España, Portugal, Polonia y Países Bajos.Fundación Española para la Ciencia y la Tecnología-Ministerio de Ciencia, Innovación y Universidades; Consejería de la Presidencia, Administración Pública e Interior de la Junta de Andalucía; Estrategia de Política de Investigación y Transferencia de la Universidad de Huelva; Cátedra de Innovación Social de Aguas de Huelva; Cátedra de la Provincia; Grupo de investigación TEP-192 de Control y Robótica; Centro de Investigación en Tecnología, Energía y Sostenibilidad (CITES
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