1,528 research outputs found

    Spanish validation of the locus of control questionnaire in sport for children

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    El locus de control ha sido estudiado en el deporte, sin embargo no existía un instrumento válido para evaluarlo en deporte infantil. Este estudio lleva a cabo la validación española del Children´s Sport Locus of Control Scale (CSLCS) que desarrollaron Tsai y Hsieh (2015). La adaptación presenta dos fases: una primera exploratoria con 248 niños entre 7 y 16 años para observar el comportamiento cualitativo de los ítems; y una segunda con 221 deportistas entre 8 y 22 años en la que se modificó el cuestionario para ajustarlo a los resultados obtenidos. Se obtiene una escala final de 10 ítems, con 5 ítems por dimensión (interna y externa), que presenta un ajuste adecuado. Los resultados demuestran que la versión española de la escala posee cualidades psicométricas adecuadas para ser utilizada en la investigación y la práctica aplicada en la evaluación deportiva infantilLocus of control has been studied in the sport context, however there was no valid instrument to evaluate it in children's sport. This study adapts into Spanish and validates the Children's Locus of Control Scale for Sport (CSLCS) in the Spanish language. This CSLCS was developed by Tsai y Hsieh (2015). The adaptation has two phases: an initial screening of 248 children between the ages of 7 and 16 to observe the qualitative behavior of the items; and a second one with 221 athletes with children between the ages of 8 and 22 in which the questionnaire was modified to fit the results. A final 10-item scale was obtained, with 5 items per dimension (internal and external), which presents an adequate fit. Results show that the Spanish version of the scale possesses adequate psychometric qualities for its use in research and applied fields in child´s sport evaluatio

    Myristic acid potentiates palmitic acid-induced lipotoxicity and steatohepatitis associated with lipodystrophy by sustaning de novo ceramide synthesis.

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    Palmitic acid (PA) induces hepatocyte apoptosis and fuels de novo ceramide synthesis in the endoplasmic reticulum (ER). Myristic acid (MA), a free fatty acid highly abundant in copra/palmist oils, is a predictor of nonalcoholic steatohepatitis (NASH) and stimulates ceramide synthesis. Here we investigated the synergism between MA and PA in ceramide synthesis, ER stress, lipotoxicity and NASH. Unlike PA, MA is not lipotoxic but potentiated PA-mediated lipoapoptosis, ER stress, caspase-3 activation and cytochrome c release in primary mouse hepatocytes (PMH). Moreover, MA kinetically sustained PA-induced total ceramide content by stimulating dehydroceramide desaturase and switched the ceramide profile from decreased to increased ceramide 14:0/ceramide16:0, without changing medium and long-chain ceramide species. PMH were more sensitive to equimolar ceramide14:0/ceramide16:0 exposure, which mimics the outcome of PA plus MA treatment on ceramide homeostasis, than to either ceramide alone. Treatment with myriocin to inhibit ceramide synthesis and tauroursodeoxycholic acid to prevent ER stress ameliorated PA plus MA induced apoptosis, similar to the protection afforded by the antioxidant BHA, the pan-caspase inhibitor z-VAD-Fmk and JNK inhibition. Moreover, ruthenium red protected PMH against PA and MA-induced cell death. Recapitulating in vitro findings, mice fed a diet enriched in PA plus MA exhibited lipodystrophy, hepatosplenomegaly, increased liver ceramide content and cholesterol levels, ER stress, liver damage, inflammation and fibrosis compared to mice fed diets enriched in PA or MA alone. The deleterious effects of PA plus MA-enriched diet were largely prevented by in vivo myriocin treatment. These findings indicate a causal link between ceramide synthesis and ER stress in lipotoxicity, and imply that the consumption of diets enriched in MA and PA can cause NASH associated with lipodystrophy

    Crystallographic orientation inhomogeneity and crystal splitting in biogenic calcite

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    The calcitic prismatic units forming the outer shell of the bivalve Pinctada margaritifera have been analysed using scanning electron microscopy–electron back-scatter diffraction, transmission electron microscopy and atomic force microscopy. In the initial stages of growth, the individual prismatic units are single crystals. Their crystalline orientation is not consistent but rather changes gradually during growth. The gradients in crystallographic orientation occur mainly in a direction parallel to the long axis of the prism, i.e. perpendicular to the shell surface and do not show preferential tilting along any of the calcite lattice axes. At a certain growth stage, gradients begin to spread and diverge, implying that the prismatic units split into several crystalline domains. In this way, a branched crystal, in which the ends of the branches are independent crystalline domains, is formed. At the nanometre scale, the material is composed of slightly misoriented domains, which are separated by planes approximately perpendicular to the c-axis. Orientational gradients and splitting processes are described in biocrystals for the first time and are undoubtedly related to the high content of intracrystalline organic molecules, although the way in which these act to induce the observed crystalline patterns is a matter of future research

    Benefits of vibration training in the neuromuscular system of the elderly

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    Introducción: El entrenamiento vibratorio puede ser una opción de intervención óptima para prevenir la pérdida de masa muscular en adultos mayores. Objetivo: Comprobar la efectividad del entrenamiento vibratorio en el sistema neuromuscular de los adultos mayores. Material y método: Revisión bibliográfica en las bases de datos Medline, CINAHL, WOS y PEDro, mediante la combinación de los descriptores del Medical Subjects Headings referentes a entrenamiento vibratorio, fuerza muscular, masa muscular y personas mayores. Resultados: Los estudios localizados sobre el entrenamiento vibratorio en personas mayores se realizaron, bien como única intervención, o en combinación con otro tipo de ejercicios de fuerza, aeróbicos, de equilibrio o de flexibilidad. La diversidad de protocolos empleados dificulta una comparación entre estudios. Conclusión: El entrenamiento con plataformas vibratorias demuestra ser un método de entrenamiento de la fuerza seguro, adecuado y eficaz para la población de mayor edad, pero con resultados similares al ejercicio de resistencia convencional

    The Periosteal Bone Surface is Less Mechano-Responsive than the Endocortical

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    Dynamic processes modify bone micro-structure to adapt to external loading and avoid mechanical failure. Age-related cortical bone loss is thought to occur because of increased endocortical resorption and reduced periosteal formation. Differences in the (re)modeling response to loading on both surfaces, however, are poorly understood. Combining in-vivo tibial loading, in-vivo micro- tomography and finite element analysis, remodeling in C57Bl/6J mice of three ages (10, 26, 78 week old) was analyzed to identify differences in mechano- responsiveness and its age-related change on the two cortical surfaces. Mechanical stimulation enhanced endocortical and periosteal formation and reduced endocortical resorption; a reduction in periosteal resorption was hardly possible since it was low, even without additional loading. Endocortically a greater mechano-responsiveness was identified, evident by a larger bone-forming surface and enhanced thickness of formed bone packets, which was not detected periosteally. Endocortical mechano-responsiveness was better conserved with age, since here adaptive response declined continuously with aging, whereas periosteally the main decay in formation response occurred already before adulthood. Higher endocortical mechano-responsiveness is not due to higher endocortical strains. Although it is clear structural adaptation varies between different bones in the skeleton, this study demonstrates that adaptation varies even at different sites within the same bone

    Genetic variability in two spanish horse populations: preliminary results

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    The genetic variability has been analyzed through the allelic frequencies distribution of ten STR (Short Tandem Repeat) equine loci of three different horse populations, Asturcón, Pottoka and Thoroughbred (PSI), which is considered as an outgroup. The genetic variability found in the pony breeds is higher than for PSI and only one of the ten loci analyzed is significantly desviated from Hardy-Weinberg equilibrium (= 0.01) in Asturcón and Pottoka populations. The FST value (0.054) shows a significant divergence between Asturcón and Pottoka, besides the genetic distance calculated between both populations is very lower compared to their relation with PSI.Para el estudio de la variabilidad genética de tres poblaciones diferentes de caballos, Asturcón, Pottoka y Pura Sangre Inglés (PSI), habiéndose constituido esta última como población de referencia, se ha analizado la distribución de las frecuencias alélicas de 10 STR (Short Tandem Repeat) loci equinos. La variabilidad genética encontrada en las razas de ponis es superior a la del PSI y solo uno de los loci analizados se desvía significativamente del equilibrio Hardy- Weinberg (=0,01) en las poblaciones de Asturcón y Pottoka. El valor FST estimado (0,054) muestra una divergencia significativa entre Asturcón y Pottoka, asimismo la distancia genética calculada entre ambas poblaciones es inferior comparada a la que tienen ambas con respecto al PSI

    La Formación de Bellmunt (Unidad del Cadí, Pirineo oriental): aportaciones bioestratigráficas de los sistemas lacustres y palustres asociados

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    The Bellmunt Fm is an alluvial synorogenic unit which was deposited under the influence of the southward displacement of succesive pyrenean nappes. This unit includes, in the boundary between its lower and middle part, many lacustrine and palustrine beds with an abundant fossil fauna and flora. This fossil record allows to recognize thepaleoenviromental andpaleoclimatic scenary. Charophytes and fossil mammals indicate a Middle and Lower Bartonian age for this Formation

    Bistability in the Tunnelling Current through a Ring of NN Coupled Quantum Dots

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    We study bistability in the electron transport through a ring of N coupled quantum dots with two orbitals in each dot. One orbital is localized (called b orbital) and coupling of the b orbitals in any two dots is negligible; the other is delocalized in the plane of the ring (called d orbital), due to coupling of the d orbitals in the neighboring dots, as described by a tight-binding model. The d orbitals thereby form a band with finite width. The b and d orbitals are connected to the source and drain electrodes with a voltage bias V, allowing the electron tunnelling. Tunnelling current is calculated by using a nonequilibrium Green function method recently developed to treat nanostructures with multiple energy levels. We find a bistable effect in the tunnelling current as a function of bias V, when the size N>50; this effect scales with the size N and becomes sizable at N~100. The temperature effect on bistability is also discussed. In comparison, mean-field treatment tends to overestimate the bistable effect.Comment: Published in JPSJ; minor typos correcte
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