265 research outputs found

    Fatiga y rendimiento en la velocidad y salto

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    El presente trabajo expone una comparación entre dos tipos de actividades fatigantes (pliometría y multisaltos) y su relación de dependencia con el rendimiento en la velocidad y la capacidad de salto, acciones propias de numerosas actividades deportivas. Para ello se utilizó un único grupo control de 11 sujetos universitarios que pasó por dos sesiones, separadas temporalmente una semana. En la primera sesión se utilizó como ejercicio de prefatiga los multisaltos, mientras que en la segunda sesión, la pliometría. Se realizó un análisis estadístico descriptivo, un análisis de contraste, t-Student y ANOVA, y un análisis de correlación de Pearson. Los resultados demostraron de forma significativa que se obtuvieron mejores registros en la capacidad de salto durante la sesión en la que se realizaron previamente ejercicios de pliometría, y en la velocidad durante la sesión de multisaltos

    Tug-of-war between corrugation and binding energy: revealing the formation of multiple moiré patterns on a strongly interacting graphene-metal system

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    The formation of multidomain epitaxial graphene on Rh(111) under ultra-high vacuum (UHV) conditions has been characterized by scanning tunnelling microscopy (STM) measurements and density functional theory (DFT) calculations. At variance with the accepted view for strongly interacting graphene-metal systems, we clearly demonstrate the formation of different rotational domains leading to multiple moiré structures with a wide distribution of surface periodicities. Experiments reveal a correlation between the STM apparent corrugation and the lattice parameter of the moiré unit cell, with corrugations of just 30-40 pm for the smallest moirés. DFT calculations for a relevant selection of these moiré patterns show much larger height differences and a non-monotonic behaviour with the moiré size. Simulations based on non-equilibrium Green's function (NEGF) methods reproduce quantitatively the experimental trend and provide a detailed understanding of the interplay between electronic and geometric contributions in the STM contrast of graphene systems. Our study sheds light on the subtle energy balance among strain, corrugation and binding that drives the formation of the moiré patterns in all graphene/metal systems and suggests an explanation for the success of an effective model only based on the lattice mismatch. Although low values of the strain energy are a necessary condition, it is the ability of graphene to corrugate in order to maximize the areas of favourable graphene-metal interactions that finally selects the stable configurationsWe acknowledge financial support from Spanish grants MAT2013-41636-P, MAT2011-23627, MAT2011-26534, CSD2010-00024 (MINECO, Spain) and S2009/MAT-1467 (CAM, Spain). A.J.M.G. was supported by a Marie Curie action under the Seventh Framework Programme. P.P. was supported by the Ramón y Cajal Progra

    Supported Metal Nanohydrides for Hydrogen Storage

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    Producción CientíficaAdsorption of hydrogen on graphdiyne (GDY) and boron-graphdiyne (BGDY) doped with palladium clusters has been investigated by performing density functional calculations. Pd6 fits well on the large holes of those porous layers, preserving its octahedral structure in GDY and changing it to a capped trigonal bipyramid structure in BGDY. Pd6GDY adsorbs up to five H2 molecules with sizable adsorption energies, two dissociated and three nondissociated. The dissociation barrier of H2 on the Pd6GDY cluster is 0.58 eV. Pd6BGDY can adsorb up to six molecules, three dissociated and three nondissociated, and the dissociation barrier of H2 on Pd6BGDY is 0.23 eV. In both cases, the dissociation barriers are substantially smaller than the corresponding dissociation barriers on undoped GDY and BGDY. The Pd clusters saturated with hydrogen can be viewed as nanohydrides. Spilling of the adsorbed hydrogen atoms toward the GDY and BGDY substrates is hindered by large activation barriers. We then propose using BGDY and GDY layers as support platforms for metal nanohydrides. The amount of stored hydrogen using Pd as the dopant is below the target of 6% of hydrogen in weight, but replacing Pd by a lighter metal with similar or higher affinity for hydrogen would substantially enhance the storage.Ministerio de Ciencia e Innovación (MCIN/AEI/ 10.13039/501100011033)(Grant PID2019-104924RB-I00

    Aprendizaje de técnicas avanzadas de Programación Orientada a Objetos mediante programación de juegos

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    Los juegos constituyen un área muy adecuada para la elaboración de prácticas de programación. En muchos casos, permiten la aplicación directa de los contenidos teóricos impartidos en otras asignaturas teóricas, como las relacionadas con estructuras de datos y algoritmia. Además, al ser prácticas que se alejan de los típicos “problemas de juguete”, permiten introducir nuevas técnicas o tecnologías con demanda en el mundo laboral. En este artículo presentamos la experiencia realizada en un curso de Laboratorio de Programación III, en la que hemos propuesto la implementación de Sudokus en Java. Como veremos, el problema nos ha permitido poner en práctica conceptos de estructuras de datos y algoritmia, así como patrones de diseño y programación de dispositivos móviles

    Ultraviolet laser patterning of porous silicon

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    This work reports on the fabrication of 1D fringed patterns on nanostructured porous silicon (nanoPS) layers (563, 372, and 290nm thick). The patterns are fabricated by phase-mask laser interference using single pulses of an UV excimer laser (193nm, 20ns pulse duration). The method is a single-step and flexible approach to produce a large variety of patterns formed by alternate regions of almost untransformed nanoPS and regions where its surface has melted and transformed into Si nanoparticles (NPs). The role of laser fluence (5-80mJcm-2), and pattern period (6.3-16µm) on pattern features and surface structuring are discussed. The results show that the diameter of Si NPs increases with fluence up to a saturation value of 75nm for a fluence ˜40mJcm-2. In addition, the percentage of transformed to non-transformed region normalized to the pattern period follows similar fluence dependence regardless the period and thus becomes an excellent control parameter. This dependence is fitted within a thermal model that allows for predicting the in-depth profile of the pattern. The model assumes that transformation occurs whenever the laser-induced temperature increase reaches the melting temperature of nanoPS that has been found to be 0.7 of that of crystalline silicon for a porosity of around 79%. The role of thermal gradients across the pattern is discussed in the light of the experimental results and the calculated temperature profiles, and shows that the contribution of lateral thermal flow to melting is not significant for pattern periods =6.3µm.Postprint (published version

    Denitrification in a hypersaline lake–aquifer system (Pétrola Basin, Central Spain): The role of recent organic matter and Cretaceous organic rich sediments

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    Agricultural regions in semi-arid to arid climates with associated saline wetlands are one of the most vulnerable environments to nitrate pollution. The Pétrola Basin was declared vulnerable to NO3 − pollution by the Regional Government in 1998, and the hypersaline lake was classified as a heavily modified body of water. The study assessed groundwater NO3 − through the use of multi-isotopic tracers (δ15N, δ34S, δ13C, δ18O) coupled to hydrochemistry in the aquifer connected to the eutrophic lake. Hydrogeologically, the basin shows two main flow components: regional groundwater flow from recharge areas (Zone 1) to the lake (Zone 2), and a density-driven flow from surface water to the underlying aquifer (Zone 3). In Zones 1 and 2, δ15NNO3 and δ18ONO3 suggest that NO3 − from slightly volatilized ammonium synthetic fertilizers is only partially denitrified. The natural attenuation of NO3 − can occur by heterotrophic reactions. However, autotrophic reactions cannot be ruled out. In Zone 3, the freshwater–saltwater interface (down to 12–16 m below the ground surface) is a reactive zone for NO3 − attenuation. Tritium data suggest that the absence of NO3 − in the deepest zones of the aquifer under the lake can be attributed to a regional groundwater flow with long residence time. In hypersaline lakes the geometry of the density-driven flow can play an important role in the transport of chemical species that can be related to denitrification processes.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUECastilla–La Mancha GovernmentSpanish GovernmentCatalan Governmentpu

    Structural and Electronic Properties of Small Neutral (MgO)n Clusters

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    Ab initio Perturbed Ion (PI) calculations are reported for neutral stoichiometric (MgO)n clusters (n<14). An extensive number of isomer structures was identified and studied. For the isomers of (MgO)n (n<8) clusters, a full geometrical relaxation was considered. Correlation corrections were included for all cluster sizes using the Coulomb-Hartree-Fock (CHF) model proposed by Clementi. The results obtained compare favorably to the experimental data and other previous theoretical studies. Inclusion of correlaiotn is crucial in order to achieve a good description of these systems. We find an important number of new isomers which allows us to interpret the experimental magic numbers without the assumption of structures based on (MgO)3 subunits. Finally, as an electronic property, the variations in the cluster ionization potential with the cluster size were studied and related to the structural isomer properties.Comment: 24 pages, LaTeX, 7 figures in GIF format. Accepted for publication in Phys. Rev.

    Evolución de la preparación física en el fútbol

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    The In the area of sport, has been being shown, one of the most important factors for the athlete to perform at its best is to have a good physical condition. Regardless of the technical improvement, medical support nutrition, new materials, etc.. physical training has in recent years experienced an extraordinary evolution in both quantity and quality. In recent decades, sports science have greatly evolved as a result of this progress are appearing in the physical preparation in football at all levels. In this article the main trends that have historically been being used to improve various physical qualities involving this sport, with the aim of achieving the best possible performance are analyzed.En el ámbito del deporte, ha venido siendo demostrado, que uno de los factores más importantes para que el deportista pueda rendir en las mejores condiciones es el de tener una buena preparación física. Independientemente del perfeccionamiento técnico, apoyo médico, nutrición, nuevos materiales, etc. la preparación física ha experimentado en los últimos años una evolución extraordinaria, tanto en cantidad como en calidad. En las últimas décadas las ciencias del deporte han evolucionado enormemente, producto de ello son los avances aparecidos en la preparación física en el fútbol a todos sus niveles. En este artículo se analizan las principales tendencias que históricamente han venido empleándose para la mejora de las diferentes cualidades físicas que implican la práctica de este deporte, con el objetivo de alcanzar el mejor rendimiento posible

    RIPK1 is a critical modulator of both tonic and TLR-responsive inflammatory and cell death pathways in human macrophage differentiation

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    In this study, we took advantage of human-induced pluripotent stem cells (hiPSC) and CRISPR/Cas9 technology to investigate the potential roles of RIPK1 in regulating hematopoiesis and macrophage differentiation, proinflammatory activation, and cell death pathways. Knock-out of RIPK1 in hiPSCs demonstrated that this protein is not required for erythro-myeloid differentiation. Using a well-established macrophage differentiation protocol, knock-out of RIPK1 did not block the differentiation of iPSC-derived macrophages, which displayed a similar phenotype to WT hiPSC-derived macrophages. However, knock-out of RIPK1 leads to a TNFα-dependent apoptotic death of differentiated hiPSC-derived macrophages (iPS-MΦ) and progressive loss of iPS-MΦ production irrespective of external pro-inflammatory stimuli. Live video analysis demonstrated that TLR3/4 activation of RIPK1 KO hiPSC-derived macrophages triggered TRIF and RIPK3-dependent necroptosis irrespective of caspase-8 activation. In contrast, TLR3/4 activation of WT macrophages-induced necroptosis only when caspases were inhibited, confirming the modulating effect of RIPK1 on RIPK3-mediated necroptosis through the FADD, Caspase-8 pathway. Activation of these inflammatory pathways required RIPK3 kinase activity while RIPK1 was dispensable. However, loss of RIPK1 sensitizes macrophages to activate RIPK3 in response to inflammatory stimuli, thereby exacerbating a potentially pathological inflammatory response. Taken together, these results reveal that RIPK1 has an important role in regulating the potent inflammatory pathways in authentic human macrophages that are poised to respond to external stimuli. Consequently, RIPK1 activity might be a valid target in the development of novel therapies for chronic inflammatory diseases.España, MINECO/FEDER SAF2015-64171

    EVIDENT smartphone app, a new method for the dietary record: comparison with a food frequency questionnaire

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    Background: More alternatives are needed for recording people’s normal diet in different populations, especially adults or the elderly, as part of the investigation into the effects of nutrition on health. Objective: The aim of this study was to compare the estimated values of energy intake, macro- and micronutrient, and alcohol consumption gathered using the EVIDENT II smartphone app against the data estimated with a food frequency questionnaire (FFQ) in an adult population aged 18 to 70 years. Methods: We included 362 individuals (mean age 52 years, SD 12; 214/362, 59.1% women) who were part of the EVIDENT II study. The participants registered their food intake using the EVIDENT app during a period of 3 months and through an FFQ. Both methods estimate the average nutritional composition, including energy intake, macro- and micronutrients, and alcohol. Through the app, the values of the first week of food recording, the first month, and the entire 3-month period were estimated. The FFQ gathers data regarding the food intake of the year before the moment of interview. Results: The intraclass correlation for the estimation of energy intake with the FFQ and the app shows significant results, with the highest values returned when analyzing the app’s data for the full 3-month period (.304, 95% CI 0.144-0.434; P<.001). For this period, the correlation coefficient for energy intake is .233 (P<.001). The highest value corresponds to alcohol consumption and the lowest to the intake of polyunsaturated fatty acids (r=.676 and r=.155; P<.001), respectively. The estimation of daily intake of energy, macronutrients, and alcohol presents higher values in the FFQ compared with the EVIDENT app data. Considering the values recorded during the 3-month period, the FFQ for energy intake estimation (Kcal) was higher than that of the app (a difference of 408.7, 95% CI 322.7-494.8; P<.001). The same is true for the other macronutrients, with the exception g/day of saturated fatty acids (.4, 95% CI −1.2 to 2.0; P=.62). Conclusions: The EVIDENT app is significantly correlated to FFQ in the estimation of energy intake, macro- and micronutrients, and alcohol consumption. This correlation increases with longer app recording periods. The EVIDENT app can be a good alternative for recording food intake in the context of longitudinal or intervention studies. Trial Registration: ClinicalTrials.gov NCT02016014; http://clinicaltrials.gov/ct2/show/NCT02016014 (Archived by WebCite at http://www.webcitation.org/760i8EL8Q).Spanish Ministry of Science and Innovation and Carlos III Health Institute/European Regional Development Fund (FIS: PI13/00618, PI13/01526, PI13/00058, PI13/01635, PI13/02528, PI12/01474; RETICS: RD12/0005, RD16/0007), Regional Health Management of Castilla and León (GRS 1191/B/15, GRS 909/B/14, GRS 770/B/13), and the Infosalud Foundatio
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