1,788 research outputs found

    Quantum optical signals in telecommunication networks

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    Introducción a una red óptica metropolitana cuántica donde señales cuánticas y convencionales son multiplexadas en longitud de onda utilizando bandas separadas del espectro óptico. El enrutado se realiza con componentes pasivos para no perturbar los qubits. Se estudian dos redes: red de acceso WDM-PON y red metropolitana completa con backbone DWDM y redes de acceso WDM-PON

    Kinematic and kinetic patterns related to free-walking in Parkinson's disease

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    The aim of this study is to compare the properties of free-walking at a natural pace between mild Parkinson’s disease (PD) patients during the ON-clinical status and two control groups. In-shoe pressure-sensitive insoles were used to quantify the temporal and force characteristics of a 5-min free-walking in 11 PD patients, in 16 young healthy controls, and in 12 age-matched healthy controls. Inferential statistics analyses were performed on the kinematic and kinetic parameters to compare groups’ performances, whereas feature selection analyses and automatic classification were used to identify the signature of parkinsonian gait and to assess the performance of group classification, respectively. Compared to healthy subjects, the PD patients’ gait pattern presented significant differences in kinematic parameters associated with bilateral coordination but not in kinetics. Specifically, patients showed an increased variability in double support time, greater gait asymmetry and phase deviation, and also poorer phase coordination. Feature selection analyses based on the ReliefF algorithm on the differential parameters in PD patients revealed an effect of the clinical status, especially true in double support time variability and gait asymmetry. Automatic classification of PD patients, young and senior subjects confirmed that kinematic predictors produced a slightly better classification performance than kinetic predictors. Overall, classification accuracy of groups with a linear discriminant model which included the whole set of features (i.e., demographics and parameters extracted from the sensors) was 64.1

    Magnetic resonance imaging in the prenatal diagnosis of neural tube defects

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    OBJECTIVE: To assess the role of magnetic resonance imaging (MRI) in the prenatal diagnosis of neural tube defects (NTDs). BACKGROUND: NTDs comprise a heterogeneous group of congenital anomalies that derive from the failure of the neural tube to close. Advances in ultrasonography and MRI have considerably improved the diagnosis and treatment of NTDs both before and after birth. Ultrasonography is the first technique in the morphological study of the fetus, and it often makes it possible to detect or suspect NTDs. Fetal MRI is a complementary technique that makes it possible to clear up uncertain ultrasonographic findings and to detect associated anomalies that might go undetected at ultrasonography. The progressive incorporation of intrauterine treatments makes an accurate diagnosis of NTDs essential to ensure optimal perinatal management. The ability of fetal MRI to detect complex anomalies that affect different organs has been widely reported, and it can be undertaken whenever NTDs are suspected. CONCLUSION: We describe the normal appearance of fetal neural tube on MRI, and we discuss the most common anomalies involving the structures and the role of fetal MRI in their assessment. KEY POINTS: • To learn about the normal anatomy of the neural tube on MRI • To recognise the MR appearance of neural tube defects • To understand the value of MRI in assessing NTD

    Kinetic study of the hydrodechlorination of chloromethanes with activated-carbon-supported metallic catalysts

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    This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in Industrial and Engineering Chemistry Research, copyright © American Chemical Society after peer review. To access the final edited and published work, see http://pubs.acs.org/doi/abs/10.1021/ie5042484The kinetics of the hydrodechlorination (HDC) of dichloromethane (DCM) and chloroform (TCM) with Pd, Pt, Rh, and Ru on activated carbon catalysts has been studied at temperatures between 100 and 250 °C. Different kinetic models have been checked, namely, pseudo-first-order and Langmuir-Hinshelwood-Hougen-Watson (LHHW) with adsorption, chemical reaction, or desorption control. The HDC of DCM and TCM with the Pd and Pt catalysts was well-described by the LHHW model with reactant adsorption as the rate-controlling step. However, with Rh and Ru catalysts, chemical reaction and desorption of the reaction products appear to be the rate-controlling steps in the HDC of DCM and TCM, respectively. In this last case, different sets of complex reactions seem to occur on the surface of the catalyst depending on the temperature, preventing determination of a confident value of the activation energy, because of the formation of oligomeric coke-like deposits and the subsequent severe deactivation of these catalysts. The corresponding kinetic parameters for the proposed models have been calculatedThe authors gratefully acknowledge financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) through the project CTM2011-28352. M. Martín Martínez and A. Arévalo Bastante acknowledges the Spanish Ministerio de Ciencia e nnovación (MICINN) and the European Social Fund for her research gran

    Exchange bias in laterally oxidized Au/Co/Au nanopillars

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    Au/Co/Au nanopillars fabricated by colloidal lithography of continuous trilayers exhibit and enhanced coercive field and the appearance of an exchange bias field with respect to the continuous layers. This is attributed to the lateral oxidation of the Co interlayer that appears upon disc fabrication. The dependence of the exchange bias field on the Co nanodots size and on the oxidation degree is analyzed and its microscopic origin clarified by means of Monte Carlo simulations based on a model of a cylindrical dot with lateral core/shell structure.Comment: 8 pages, 4 figures. Published in Appl. Phys. Let

    Tuning the size, composition and structure of Au and Co50Au50 Nanoparticles by High-Power Impulse Magnetron Sputtering in gas-phase Synthesis

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    Gas-phase synthesis of nanoparticles with different structural and chemical distribution is reported using a circular magnetron sputtering in an ion cluster source by applying high-power impulses. The influence of the pulse characteristics on the final deposit was evaluated on Au nanoparticles. The results have been compared with the more common direct current approach. In addition, it is shown for the first time that high-power impulses in magnetron based gas aggregation sources allows the growth of binary nanoparticles, CoAu in this case, with a variety of crystalline and chemical arrangements which are analyzed at the atomic level

    Environment-driven reactivity of H2 on PdRu surface alloys

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    The dissociative adsorption of molecular hydrogen on PdxRu1−x/Ru(0001) (0 ≤ x ≤ 1) has been investigated by means of He atom scattering, Density Functional Theory and quasi-classical trajectory calculations. Regardless of their surroundings, Pd atoms in the alloy are always less reactive than Ru ones. However, the reactivity of Ru atoms is enhanced by the presence of nearest neighbor Pd atoms. This environment-dependent reactivity of the Ru atoms in the alloy provides a sound explanation for the striking step-like dependence of the initial reactive sticking probability as a function of the Pd concentration observed in experiments. Moreover, we show that these environment-dependent effects on the reactivity of H2 on single atoms allow one to get around the usual constraint imposed by the Brønsted–Evans–Polanyi relationship between the reaction barrier and chemisorption energy.Fil: Ramos Acevedo, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; ArgentinaFil: Minniti, M.. Universidad Autónoma de Madrid; EspañaFil: Díaz, C.. Universidad Autónoma de Madrid; EspañaFil: Farias, D.. Universidad Autónoma de Madrid; EspañaFil: Miranda, R.. Universidad Autónoma de Madrid; España. Instituto Madrileño de Estudios Avanzados en Nanociencia; EspañaFil: Martín, F.. Universidad Autónoma de Madrid; España. Instituto Madrileño de Estudios Avanzados en Nanociencia; EspañaFil: Martinez, Alejandra Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; ArgentinaFil: Busnengo, Heriberto Fabio. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentin

    The role of emotional intelligence and self-care in the stress perception during COVID-19 outbreak: An intercultural moderated mediation analysis

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    Background: The relationship between emotional intelligence (EI) and stress has been widely studied, as well as the beneficial role of self-care to maintain health and wellbeing. However, the joint contribution of EI and self- care in predicting stress has not been examined during COVID-19 lockdown. This study aimed to examine the mediating role of self-care in the relationship between EI and stress and the potential moderator role of gender. Methods: A sample of 1082 participants from four Hispanic countries completed measures related to socio- demographic, trait emotional intelligence (Trait Meta-Mood Scale), self-care activities (Self-care Activities Screening Scale) and stress (Perceived Stress Scale). Results: Mediation analyses revealed that self-care increased the explained variance of the prediction of stress by EI dimensions after controlling gender and age. However, gender only moderated the relationship between selfcare and stress in the mediation model corresponding to emotional attention. Conclusions: Data supported a general model for the interaction of EI and self-care as contributing factors of stress. Further research is needed to replicate it in more culturally distant samples and to fully explore the po- tential role of gender differences. Future intervention programs should include a balanced combination of EI and self-care to increase their benefits on people’s healt

    Increasing trend in the prevalence of morbid obesity in Spain: from 1.8 to 6.1 per thousand in 14 years

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    Obesity, and especiallymorbid obesity, increases the risk of cardiovascular as well as non-cardiovascular diseases. Our objective was to ascertain the trends in morbid obesity in Spain from 1993 to 2006 using representative data from 106,048 participants in the National Health Surveys. An age-adjusted Poisson regression model stratified by sex was fitted using morbid obesity as the dependent variable. An increasing trend in prevalent morbid obesity from 1.8 to 6.1 per thousand participants was found (increase > 200%). Morbid obesity prevalence was higher in women. After adjusting for age, a monotonically increasing prevalence of morbid obesity was apparent for both men and women: the relative increase was 4% per year in women and 12% per year in men. These trends highlight the importance of preventive actions
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