248 research outputs found

    The Schrödinger equation in the context of fluid mechanics

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    [ES] Se deriva un mapeo entre la ecuación de Schr¿odinger y la de Navier-Stokes, que generaliza el que propuso Madelung en 1926 con la ecuación de Euler. Dado que la mecánica de fluidos es el paradigma de teoría emergente, estos mapeos apoyan la interpretación de la mecánica cuántica como una teoría efectiva, emergente a partir de otra más fundamental. En el nuevo mapeo, además, el potencial cuántico se identifica con el término viscoso, en línea con recientes estudios que afirman que la cuanticidad tiene un origen disipativo.[EN] We derive a mapping between the Schro¿ dinger equation and the Navier-Stokes equation, which generalizes the one proposed by Madelung in 1926 with the Euler equation. Since ¿uid mechanics is the paradigm of an emergent theory, these maps support the interpretation of quantum mechanics as an effective theory, emerging from a more fundamental one. In the new mapping, moreover, the quantum potential is identi¿ed with the viscous term, in line with recent studies that claim that quantumness has a dissipative origin.J. Vazquez agradece a Manuel Monleón Pradas las referencias y discusiones sobre mecánica del medio continuo, y agradece la financiación al Programa de Becas de Movilidad Académica de la AUIP y al Programa de Ayudas de Investigación y Desarrollo de la UPV. D. Cabrera agradece la financiación del proyecto con Ref. FIS2014-51948-C2-1-P del Ministerio de Economía y Competitividad (España).Cabrera, D.; Fernández De Córdoba Castellá, PJ.; Isidro San Juan, JM.; Valdés Placeres, JM.; Vazquez Molina, J. (2016). La ecuación de Schrödinger en el contexto de la mecánica de fluidos. Revista Cubana de Fisica. 33(2):98-101. http://hdl.handle.net/10251/150048S9810133

    Electrochemical integration of graphene with light absorbing copper-based thin films

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    We present an electrochemical route for the integration of graphene with light sensitive copper-based alloys used in optoelectronic applications. Graphene grown using chemical vapor deposition (CVD) transferred to glass is found to be a robust substrate on which photoconductive Cu_{x}S films of 1-2 um thickness can be deposited. The effect of growth parameters on the morphology and photoconductivity of Cu_{x}S films is presented. Current-voltage characterization and photoconductivity decay experiments are performed with graphene as one contact and silver epoxy as the other

    A novel application of entropy analysis for assessing changes in movement variability during cumulative tackles in young elite rugby league players.

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    The aim of this study was to identify between-position (forwards vs. backs) differences in movement variability in cumulative tackle events training during both attacking and defensive roles. Eleven elite adolescent male rugby league players volunteered to participate in this study (mean ± SD, age; 18.5 ± 0.5 years, height; 179.5 ± 5.0 cm, body mass; 88.3 ± 13.0 kg). Participants performed a drill encompassing four blocks of six tackling (i.e. tackling an opponent) and six tackled (i.e. being tackled by an opponent while carrying a ball) events (i.e. 48 total tackles) while wearing a micro-technological inertial measurement unit (WIMU, Realtrack Systems, Spain). The acceleration data were used to calculate sample entropy (SampEn) to analyse the movement variability during tackles performance. In tackling actions SampEn showed significant between-position differences in block 1 (p = 0.0001) and block 2 (p = 0.0003). Significant between-block differences were observed in backs (block 1 vs 3, p = 0,0021; and block 1 vs 4, p = 0,0001) but not in forwards. When being tackled, SampEn showed significant between-position differences in block 1 (p = 0.0007) and block 3 (p = 0.0118). Significant between-block differences were only observed for backs in block 1 vs 4 (p = 0,0025). Movement variability shows a progressive reduction with cumulative tackle events, especially in backs and when in the defensive role (tackling). Forwards present lower movement variability values in all blocks, particularly in the first block, both in the attacking and defensive role. Entropy measures can be used by practitioners as an alternative tool to analyse the temporal structure of variability of tackle actions and quantify the load of these actions according to playing position

    Technology as 'Applied Science': a Serious Misconception that Reinforces Distorted and Impoverished Views of Science

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    The current consideration of technology as 'applied science', this is to say, as something that comes 'after' science, justifies the lack of attention paid to technology in science education. In our paper we question this simplistic view of the science-technology relationship, historically rooted in the unequal appreciation of intellectual and manual work, and we try to show how the absence of the technological dimension in science education contributes to a na¿ ve and distorted view of science which deeply affects the necessary scientific and technological literacy of all citizens

    Incidence of cardiovascular events after kidney transplantation and cardiovascular risk scores: study protocol

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    <p>Abstract</p> <p>Background</p> <p>Cardiovascular disease (CVD) is the major cause of death after renal transplantation. Not only conventional CVD risk factors, but also transplant-specific risk factors can influence the development of CVD in kidney transplant recipients.</p> <p>The main objective of this study will be to determine the incidence of post-transplant CVD after renal transplantation and related factors. A secondary objective will be to examine the ability of standard cardiovascular risk scores (Framingham, Regicor, SCORE, and DORICA) to predict post-transplantation cardiovascular events in renal transplant recipients, and to develop a new score for predicting the risk of CVD after kidney transplantation.</p> <p>Methods/Design</p> <p>Observational prospective cohort study of all kidney transplant recipients in the A Coruña Hospital (Spain) in the period 1981-2008 (2059 transplants corresponding to 1794 patients).</p> <p>The variables included will be: donor and recipient characteristics, chronic kidney disease-related risk factors, pre-transplant and post-transplant cardiovascular risk factors, routine biochemistry, and immunosuppressive, antihypertensive and lipid-lowering treatment. The events studied in the follow-up will be: patient and graft survival, acute rejection episodes and cardiovascular events (myocardial infarction, invasive coronary artery therapy, cerebral vascular events, new-onset angina, congestive heart failure, rhythm disturbances and peripheral vascular disease).</p> <p>Four cardiovascular risk scores were calculated at the time of transplantation: the Framingham score, the European Systematic Coronary Risk Evaluation (SCORE) equation, and the REGICOR (Registre Gironí del COR (Gerona Heart Registry)), and DORICA (Dyslipidemia, Obesity, and Cardiovascular Risk) functions.</p> <p>The cumulative incidence of cardiovascular events will be analyzed by competing risk survival methods. The clinical relevance of different variables will be calculated using the ARR (Absolute Risk Reduction), RRR (Relative Risk Reduction) and NNT (Number Needed to Treat).</p> <p>The ability of different cardiovascular risk scores to predict cardiovascular events will be analyzed by using the c index and the area under ROC curves. Based on the competing risks analysis, a nomogram to predict the probability of cardiovascular events after kidney transplantation will be developed.</p> <p>Discussion</p> <p>This study will make it possible to determine the post-transplant incidence of cardiovascular events in a large cohort of renal transplant recipients in Spain, to confirm the relationship between traditional and transplant-specific cardiovascular risk factors and CVD, and to develop a score to predict the risk of CVD in these patients.</p

    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

    Peatlands of Southern South America: a review

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    This is the final version. Available from International Peatland Society (IPS) / International Mire Conservation Group via the DOI in this recordSouthern South American peatlands (SSAP) play a key role in the ecological dynamics of Patagonia. They mostly comprise of undisturbed environments which provide important ecosystem services, including carbon sequestration, water reservoir and habitat for both widespread and endemic organisms. When compared with boreal peatlands, our knowledge of the functioning of SSAP is poor, and it is necessary to raise awareness about their scientific and ecological value and to ensure their conservation. This article examines a broad base of historical and contemporary published research literature on the peatlands of Chile and Argentina, from 1843 onwards, to identify gaps in knowledge, implications for the assessment of peatland functioning, and targets for peatland conservation and management. To achieve this goal, we reviewed a total of 196 research papers/reports from across the peer-reviewed and grey literature. We conclude that gaps in our knowledge and understanding of SSAP have deeply undermined the development of effective conservation strategies for these understudied ecosystems. To reverse this situation, we recommend that future research and management efforts should aim: (1) to build an inventory of the peatlands that exist in SSAP, including their location and area; (2) to ensure land use planning prioritises the maintenance of SSAP ecosystem services; (3) to improve existing legislation and protocols of good and sustainable practice for extractive activities; and (4) to carry out an extensive awareness campaign aimed at the local population and key decision makers

    Mutational spectrum of GNAL, THAP1 and TOR1A genes in isolated dystonia: study in a population from Spain and systematic literature review

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    [Objective] We aimed to investigate the prevalence of TOR1A, GNAL and THAP1 variants as the cause of dystonia in a cohort of Spanish patients with isolated dystonia and in the literature.[Methods] A population of 2028 subjects (including 1053 patients with different subtypes of isolated dystonia and 975 healthy controls) from southern and central Spain was included. The genes TOR1A, THAP1 and GNAL were screened using a combination of high-resolution melting analysis and direct DNA resequencing. In addition, an extensive literature search to identify original articles (published before 10 August 2020) reporting mutations in TOR1A, THAP1 or GNAL associated to dystonia was performed.[Results] Pathogenic or likely pathogenic variants in TOR1A, THAP1 and GNAL were identified in 0.48%, 0.57% and 0.29% of our patients, respectively. Five patients carried the variation p.Glu303del in TOR1A. A very rare variant in GNAL (p.Ser238Asn) was found as a putative risk factor for dystonia. In the literature, variations in TOR1A, THAP1 and GNAL accounted for about 6%, 1.8% and 1.1% of published dystonia patients, respectively.[Conclusions] There is a different genetic contribution to dystonia of these three genes in our patients (about 1.3% of patients) and in the literature (about 3.6% of patients), probably due the high proportion of adult-onset cases in our cohort. As regards age at onset, site of dystonia onset, and final distribution, in our population there is a clear differentiation between DYT-TOR1A and DYT-GNAL, with DYT-THAP1 likely to be an intermediate phenotype.This work was supported by the Carlos III Health Institute-European Regional Development Fund (ISCIII-FEDER) [PI14/01823, PI16/01575, PI18/01898, PI19/01576], the Andalusian Regional Ministry of Economics, Innovation, Science and Employment [CVI-02526, CTS-7685], the Andalusian Regional Ministry of Health and Welfare [PI-0741-2010, PI-0471-2013, PE-0210-2018, PI-0459-2018, PE-0186-2019], and the Alicia Koplowitz and Mutua Madrileña Foundations. Pilar Gómez-Garre was supported by the "Miguel Servet" program [MSII14/00018] (from ISCIII-FEDER) and “Nicolás Monardes” program [C-0048-2017] (from the Andalusian Regional Ministry of Health). Silvia Jesús was supported by the "Juan Rodés" program [B-0007-2019] and Daniel Macías-García by the “Río Hortega” program [CM18/00142] (both from ISCIII-FEDER). María Teresa Periñán was supported by the Spanish Ministry of Education [FPU16/05061]. Cristina Tejera was supported by VPPI-US from the University of Seville.Peer reviewe
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