Search results for " física"
showing 10 items of 920 documents
X-ray diffraction measurements of Mo melting to 119 GPa and the high pressure phase diagram
2009
In this paper, we report angle-dispersive X-ray diffraction data of molybdenum melting, measured in a double-sided laser-heated diamond-anvil cell up to a pressure of 119 GPa and temperatures up to 3400 K. The new melting temperatures are in excellent agreement with earlier measurements up to 90 GPa that relied on optical observations of melting and in strong contrast to most theoretical estimates. The X-ray measurements show that the solid melts from the bcc structure throughout the reported pressure range and provide no evidence for a high temperature transition from bcc to a close-packed structure, or to any other crystalline structure. This observation contradicts earlier interpretation…
Electromagnetic properties of low-lying states in neutron-deficient Hg isotopes: Coulomb excitation of Hg-182, Hg-184, Hg-186 and Hg-188
2019
The neutron-deficient mercury isotopes serve as a classical example of shape coexistence, whereby at low energy near-degenerate nuclear states characterized by different shapes appear. The electromagnetic structure of even-mass 182-188 Hg isotopes was studied using safe-energy Coulomb excitation of neutron-deficient mercury beams delivered by the REX-ISOLDE facility at CERN. The population of $ 0^{+}_{1,2}$01,2+, $ 2^{+}_{1,2}$21,2+and $ 4^{+}_{1}$41+states was observed in all nuclei under study. Reduced E2 matrix elements coupling populated yrast and non-yrast states were extracted, including their relative signs. These are a sensitive probe of shape coexistence and may be used to validate…
Análisis de factores motivacionales en la práctica de actividad física del alumnado de educación secundaria obligatoria en un centro de Valencia
2020
[Resumen] El objetivo del siguiente estudio fue analizar la adherencia a la práctica deportiva, el clima motivacional, la satisfacción de las necesidades básicas y la regulación de la conducta hacia la práctica de Actividad Física (AF) en alumnado de Educación Secundaria Obligatoria. Participaron en el estudio 89 estudiantes, 41 chicos y 48 chicas con edades comprendidas entre 14 y 18 años, quienes cumplimentaron el Cuestionario de Actividad Física para Adolescentes (PAQ-A), el Cuestionario de Regulación de Conducta en el Deporte (BRSQ), la Escala de medición de la Satisfacción de las Necesidades Psicológicas en el Ejercicio (PNSE), Escala de medición de los Comportamientos Controladores (C…
Hierarchical multi-criteria analysis for the selection of a triathlon
2018
Sports activities have an increasingly large impact in different fields: economy, tourism, environment, applied technology, social, culture, etc. This study analyses the most important criteria that triathletes take into account when choosing a triathlon event in Spain. The methodology used was Analytic Hierarchy Process (AHP), which quantifies the weighting of each criterion and sub-criterion in a survey. The survey was drawn up using 14 triathlete experts and was completed by 95 triathlon participants. The results show that the internal aspects associated with the development of the triathlon event, together with the proximity to the athlete's home, the layout and signage of the circuits …
Small extracellular vesicles from young adipose-derived stem cells prevent frailty, improve health span, and decrease epigenetic age in old mice.
2022
Aging is associated with an increased risk of frailty, disability, and mortality. Strategies to delay the degenerative changes associated with aging and frailty are particularly interesting. We treated old animals with small extracellular vesicles (sEVs) derived from adipose mesenchymal stem cells (ADSCs) of young animals, and we found an improvement in several parameters usually altered with aging, such as motor coordination, grip strength, fatigue resistance, fur regeneration, and renal function, as well as an important decrease in frailty. ADSC-sEVs induced proregenerative effects and a decrease in oxidative stress, inflammation, and senescence markers in muscle and kidney. Moreover, pre…
Multivariate analysis of defensive phase in football: Identification of successful behavior patterns of 2014 Brazil FIFA World Cup
2021
The aim of this study was to identify variables associated with direct recovery of the ball during defensive transitions in elite soccer and to propose a model with certain guarantees of success based on a multivariate analysis in which binary logistic regression was used to explore interaction between variables. 1,722 defensive transitions were analysed in the final stages of the FIFA World Cup 2014 in Brazil and investigated the following variables: duration of defensive transition; possession loss zone; position of players at the start and end of the defensive transitions, defensive organization, general defensive approach, period of the match, position of defence line, zone in which the…
Preliminary study of coach verbal behaviour according to game actions
2012
Guzman JF, Calpe-Gomez V. Preliminary study of coach verbal behaviour according to game actions. J. Hum. Sport Exerc. Vol. 7, No. 2, pp. 376-382, 2012. The aim of this study was to analyse the interaction between game actions in high-level handball and verbal behaviour performed by the coach. For this purpose, a match of the 1 st National Division of male Spanish handball was analysed. The type of behaviour and the content of the message reported by the coach were recorded using a modified version of Coaching Behaviour Assessment System (CBAS) and Coach Analysis and Intervention System (CAIS). About game actions, they were grouped into positive and negative. Statistically significant differ…
BCG Mass Evolution in Cosmological Hydro-Simulations
2018
We analyze the stellar growth of Brightest Cluster Galaxies (BCGs) produced by cosmological zoom-in hydrodynamical simulations of the formation of massive galaxy clusters. The evolution of the stellar mass content is studied considering different apertures, and tracking backwards either the main progenitor of the $z=0$ BCG or that of the cluster hosting the BCG at $z=0$. Both methods lead to similar results up to $z \simeq 1.5$. The simulated BCGs masses at $z=0$ are in agreement with recent observations. In the redshift interval from $z=1$ to $z=0$ we find growth factors 1.3, 1.6 and 3.6 for stellar masses within 30kpc, 50kpc and 10% of $R_{500}$ respectively. The first two factors, and in…
Anomalous Slowdown of Polymer Detachment Dynamics on Carbon Nanotubes
2019
The "wrapping" of polymer chains on the surface of carbon nanotubes allows one to obtain multifunctional hybrid materials with unique properties for a wide range of applications in biomedicine, electronics, nanocomposites, biosensors, and solar cell technologies. We study by means of molecular dynamics simulations the force-assisted desorption kinetics of a polymer from the surface of a carbon nanotube. We find that, due to the geometric coupling between the adsorbing surface and the conformation of the macromolecule, the process of desorption slows down dramatically upon increasing the windings around the nanotube. This behavior can be rationalized in terms of an overdamped dynamics with a…
“SEE, HEAR, REMAIN SILENT AND… BORED” IN THE FIELDWORK OF A PRISON: AN AUTOETHNOGRAFIC STORY
2017
Como modalidad de investigación narrativa, la autoetnografía enfatiza la parte más personal del proceso de investigación. En este artículo, el relato autoetnográfico se utiliza para reflexionar sobre el trabajo de campo de un estudio etnográfico previo desarrollado en el polideportivo de una prisión de máxima seguridad española. Los datos recogidos en aquella ocasión han sido reexaminados ahora para explicitar críticamente los pasos dados. De este modo, se ponen de manifiesto tanto los dilemas éticos enfrentados, las complejas relaciones sociales que el proceso de investigación encerró, así como la falibilidad de las decisiones tomadas.