101 research outputs found

    Prediction and final temporal errors are used for trial-to-trial motor corrections

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    Many daily life situations (e.g. dodging an approaching object or hitting a moving target) require people to correct planning of future movements based on previous temporal errors. However, the actual temporal error can be difficult to perceive: imagine a baseball batter that swings and misses a fastball. Here we show that in such situations people can use an internal error signal to make corrections in the next trial. This signal is based on the discrepancy between the actual and the planned action onset time: the prediction error. In this study, we used three interception tasks: reaching movements, saccadic eye movements and a button press that released a cursor moving ballistically for a fixed time. We found that action onset depended on the previous temporal error in the arm movement experiment only and not in the saccadic and button press experiments. However, this dependency was modulated by the movement time: faster arm movements depended less on the previous actual temporal error. An analysis using a Kalman filter confirmed that people used the prediction error rather than the previous temporal error for trial-by-trial corrections in fast arm movements, saccades and button press

    The Made In Effect on the Perception of a Spanish Industrial Product in Foreign Markets

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    With globalization, organizations must be able to look for their own differentiation with the aim to obtain sustainable competitive advantages. Differentiation across the products can be a key factor if it is also associated with their place of origin. More and more, if we consider that the nowadays economical crisis is affecting several of the most representative sectors and industries. In this respect, this paper has as aim to analyze the perception that professionals of the construction industry of some of the main European markets, exactly, France, Poland and United Kingdom, have on different types of ceramic tiles having into account their place of origin.Ante la globalización, las empresas deben ser capaces de buscar sus propios parámetros de diferenciación con el fin de obtener ventajas competitivas sostenibles. La diferenciación a través de los productos puede ser un factor clave si además va asociada a su lugar de origen. Además la crisis de las principales economías mundiales afecta a varios de sus sectores más representativos. El presente trabajo tiene como objetivo analizar la percepción que profesionales del sector de la construcción de algunos de los principales mercados europeos, concretamente, Francia, Polonia y Reino Unido, tienen sobre diferentes tipos de recubrimiento para suelos en función de su lugar de origen

    La metodología de aprendizaje basado en proyectos (ABP) aplicada a asignaturas de ciencia de los materiales en ingeniería en la red IdM@ti

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    En este trabajo se va a presentar una experiencia docente llevada a cabo de forma coordinada entre profesorado de la red de innovación docente en ciencia de materiales IdM@ti. Se trata por tanto de una experiencia interuniversitaria que se ha desarrollado entre cuatro universidades públicas españolas de manera simultánea. Concretamente, el presente trabajo muestra la implementación y el desarrollo de la aplicación de la metodología de aprendizaje basado en proyectos en asignaturas de grados de ingeniería en el ámbito de ciencia de los materiales e ingeniería metalúrgica. Se presentan las experiencias llevadas a cabo durante los últimos cuatro años, mostrando los puntos fuertes y débiles de esta metodología, así como la problemática asociada a la implementación de la misma en asignaturas de curso general de grado. Se presentarán también los resultados obtenidos, así como las principales conclusiones a las que ha llegado el equipo de trabajo de la red IdM@ti

    On the Origin of the -4.4 eV Band in CdTe(100)"

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    We calculate the bulk- (infinite system), (100)-bulk-projected- and (100)-Surface-projected Green's functions using the Surface Green's Function Matching method (SGFM) and an empirical tight-binding hamiltonian with tight-binding parameters (TBP) that describe well the bulk band structure of CdTe. In particular, we analyze the band (B--4) arising at --4.4 eV from the top of the valence band at Γ\Gamma according to the results of Niles and H\"ochst and at -4.6 eV according to Gawlik {\it et al.} both obtained by Angle-resolved photoelectron spectroscopy (ARPES). We give the first theoretical description of this band.Comment: 17 pages, Rev-TEX, CIEA-Phys. 02/9

    Neurohormonal activation induces intracellular iron deficiency and mitochondrial dysfunction in cardiac cells

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    Cèl·lula cardíaca; Deficiència de ferro; Activació neurohormonalCardiac cell; Iron deficiency; Neurohormonal activationCélula cardíaca; Deficiencia de hierro; Activación neurohormonalBackground Iron deficiency (ID) is common in patients with heart failure (HF) and is associated with poor outcomes, yet its role in the pathophysiology of HF is not well-defined. We sought to determine the consequences of HF neurohormonal activation in iron homeostasis and mitochondrial function in cardiac cells. Methods HF was induced in C57BL/6 mice by using isoproterenol osmotic pumps and embryonic rat heart-derived H9c2 cells were subsequently challenged with Angiotensin II and/or Norepinephrine. The expression of several genes and proteins related to intracellular iron metabolism were assessed by Real time-PCR and immunoblotting, respectively. The intracellular iron levels were also determined. Mitochondrial function was analyzed by studying the mitochondrial membrane potential, the accumulation of radical oxygen species (ROS) and the adenosine triphosphate (ATP) production. Results Hearts from isoproterenol-stimulated mice showed a decreased in both mRNA and protein levels of iron regulatory proteins, transferrin receptor 1, ferroportin 1 and hepcidin compared to control mice. Furthermore, mitoferrin 2 and mitochondrial ferritin were also downregulated in the hearts from HF mice. Similar data regarding these key iron regulatory molecules were found in the H9c2 cells challenged with neurohormonal stimuli. Accordingly, a depletion of intracellular iron levels was found in the stimulated cells compared to non-stimulated cells, as well as in the hearts from the isoproterenol-induced HF mice. Finally, neurohormonal activation impaired mitochondrial function as indicated by the accumulation of ROS, the impaired mitochondrial membrane potential and the decrease in the ATP levels in the cardiac cells. Conclusions HF characteristic neurohormonal activation induced changes in the regulation of key molecules involved in iron homeostasis, reduced intracellular iron levels and impaired mitochondrial function. The current results suggest that iron could be involved in the pathophysiology of HF.This work was funded by the following Grants: unrestricted grant from Vifor Pharma and Basic Research Competitive Grant in Cardiology from the Spanish Society of Cardiology 2015

    Association of physical activity with muscular strength and fat free mass in adolescents; The HELENA Study

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    Objective: To analyze the association of objectively assessed physical activity (PA) with muscular strength and fat free mass in adolescents, and to determine whether meeting the current PA recommendations is associated with higher levels of muscular strength and fat free mass. Subjects/Methods: The present cross-sectional study comprised 363 Spanish adolescents (180 females) aged 12.5-17.5 years. PA was assessed by accelerometry and expressed as average PA (counts/min), and min/day of inactive, light, moderate, vigorous and moderate to vigorous PA (MVPA). MVPA was dichotomized into <60 min/day and ≥60. Upper body muscular strength was measured with the handgrip strength test, and lower body muscular strength was measured with the standing broad jump, squat jump, counter movement jump and Abalakov tests. Fat free mass was measured by DXA. Results: We observed positive associations between vigorous PA and all the lower body muscular strength tests except for the counter movement jump in males. PA was not associated with fat free mass in both males and females. Male adolescents engaged in at least 60 min/day MVPA performed better in the standing broad jump test. Conclusions: The findings of the present study suggest that only vigorous PA is associated with muscular strength, particularly lower-body muscular strength in male adolescents

    Analysis of a bridge failure due to fire using computational fluid dynamics and finite element models

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    Bridge fires are a major concern because of the consequences that these kind of events have and because they are a real threat. However, bridge fire response is under researched and not covered in the codes. This paper studies the capabilities of numerical models to predict the fire response of a bridge and provides modeling guidelines useful for improving bridge design. To reach this goal, a numerical analysis of the fire of the I-65 overpass in Birmingham, Alabama, USA in 2002 is carried out. The analyses are based on computational fluid dynamics (CFD) for creating the fire model, and finite element (FE) software for obtaining the thermo-mechanical response of the bridge. The models are validated with parametric studies that consider heat release rate of the spilled fuel, discretization of the fire temperature in the transition from CFD to FE modeling, and boundary conditions. The validated model is used in a study to evaluate the influence of fire scenario (CFD versus standard fires), and live load. Results show that numerical models are able to simulate the response of the bridge and can be used as a basis for a performance-based approach for the design of bridges under fire. Additionally, it is found that applying the Eurocode standard and hydrocarbon fires along the full length of the bridge does not adequately represent a real bridge fire response for medium-long span bridges such as this case study. The study also shows that live loads essentially do not influence the response of the bridge. (C) 2014 Elsevier Ltd. All rights reserved.Funding for this research has been provided by the Spanish Ministry of Science and Innovation (research project BIA 2011-27104) and the Universitat Politecnica de Valencia (Research and Development Support Program PAID-06-11). Funding has also been provided to Dr. Maria Garlock by the National Science Foundation (NSF) under award number CMMI-1068252. The authors are grateful to R. King from the Federal Highway Administration of the USA, J. Black and T. Colquett from the Alabama Department of Transportation, J. Glassman from Princeton University, J.V. Aguado from Ecole Centrale de Nantes and to J. Hidalgo from the University of Edinburgh for all the information and support provided. All opinions expressed in this paper are the authors' and do not necessarily reflect the policies and views of the sponsors.Alós Moya, J.; Paya-Zaforteza, I.; Garlock, ME.; Loma-Ossorio, E.; Schiffner, D.; Hospitaler Pérez, A. (2014). Analysis of a bridge failure due to fire using computational fluid dynamics and finite element models. Engineering Structures. 68:96-110. https://doi.org/10.1016/j.engstruct.2014.02.022S961106

    Validity and reliability of the international fItness scale (IFIS) in preschool children

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    Objectives Examine the validity and reliability of parent-reported International FItness Scale (IFIS) in preschoolers. Method A cross-sectional study of 3051 Spanish preschoolers (3-5 years). Fitness was measured by PREFIT battery and reported by parents using an adapted version of the IFIS. Waist circumference was evaluated, and the waist-to-height ratio (WHtR) was calculated. Seventy-six parents of randomly selected schoolchildren completed the IFIS twice for a reliability assessment. Results ANCOVA, adjusted for sex, age and WHtR, showed that preschoolers who were scored by their parents as having average-to-very good fitness had better levels of measured physical fitness than those preschoolers who were classified as having very poor/poor fitness levels (18.1laps to 22.1laps vs 15.6laps for cardiorespiratory fitness; 6.6 kg to 7.5 kg vs 5.3 kg for muscular fitness-handgrip-; 71.7 cm to 76.4 cm vs 62.0 cm for muscular fitness-standing long jump-; 17.2s to 16.2s vs 18.2s for speed/agility; and 11.2s to 15.6s vs 8.7s for balance; p < 0.001). The weighted kappa for concordance between parent-reported fitness levels and objective assessment was poor (kappa <= 0.18 for all fitness measures). Overall, the mean values of the abdominal adiposity indicators were significantly lower in high-level fitness categories reported by parents than in low-level fitness categories (p < 0.05). The test-retest reliability ranged from 0.46 to 0.62. Conclusions The reliability of the parent-reported IFIS are acceptable, but the concordance between parents reported and objectively measures fitness levels is poor, suggesting that parents' responses may not be able to correctly classify preschoolers according to their fitness level.The PREFIT project takes place thanks to the funding linked to the Ramon y Cajal grant held by Ortega FB (RYC-2011-09011)

    Visual onset expands subjective time

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    We report a distortion of subjective time perception in which the duration of a first interval is perceived to be longer than the succeeding interval of the same duration. The amount of time expansion depends on the onset type defining the first interval. When a stimulus appears abruptly, its duration is perceived to be longer than when it appears following a stationary array. The difference in the processing time for the stimulus onset and motion onset, measured as reaction times, agrees with the difference in time expansion. Our results suggest that initial transient responses for a visual onset serve as a temporal marker for time estimation, and a systematic change in the processing time for onsets affects perceived time

    Calibration and performance tests of detectors for laser-accelerated protons

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    We present the calibration and performance tests carried out with two detectors for intense proton pulses accelerated by lasers. Most of the procedures were realized with proton beams of 0.46-5.60 MeV from a tandem accelerator. One approach made use of radiochromic films, for which we calibrated the relation between optical density and energy deposition over more than three orders of magnitude. The validity of these results and of our analysis algorithms has been confirmed by controlled irradiation of film stacks and reconstruction of the total beam charge for strongly non-uniform beam profiles. For the spectral analysis of protons from repeated laser shots, we have designed an online monitor based on a plastic scintillator. The resulting signal from a photomultiplier directly measured on a fast oscilloscope is especially useful for time-of-flight applications. Variable optical filters allow for suppression of saturation and an extension of the dynamic range. With pulsed proton beams we have tested the detector response to a wide range of beam intensities from single particles to 3 ×105 protons per 100 ns time interval.Project funded by the Spanish Ministry of Economy and Competitiveness and co-funded with FEDER's funds within the INNPACTO 2011 program under Grant No. IPT-2011-0862-900000. This work was supported by the Spanish Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica (I+D+i) under Grant No. TEC 2013-48036-C3-1-R and the Valencian Local Government under Grants PROMETEOII/2013/010 and ISIC 2011/013. The work of A. J. Gonzalez is financed by CSIC with a JAE-Doc contract under Junta de Ampliacion de Estudios program, cofinanced by the European Social Fund.Peer Reviewe
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