Análisis cinemático del viraje en el esquí alpino de competición

Esta comunicación trata sobre la aplicación de la Biomecánica Deportiva como perspectiva científica, al análisis cinemático del esquí alpino como objeto de estudio, y ha sido realizada basándose en una situación real de competición como fue el Campeonato del Mundo de 1996 celebrado en Sierra Nevada (Granada). Para el análisis de la muestra, utilizamos la metodología y las tecnologías propias de la biomecánica Deportiva como son el método indirecto y las técnicas fotogramétricas tridimensionales, basadas en la filmación del gesto deportivo utilizando el vídeo. Los resultados obtenidos muestran la existencia de un patrón general de movimiento en la muestra de esquiadoras analizadas en cuanto a las velocidades tangenciales medias del CG(S).del sistema (esquiador más implementos). Entre las conclusiones, destacamos la existencia de una reducción de la velocidad tangencial media resultante en el recorrido analizado que es mayor aún, en el instante de paso del palo de viraje en particular y cuanto más curva es la trayectoria. Atendiendo a la desviación típica del comportamiento de la velocidad media resultante, podemos decir que en este tramo de paso de la puerta encontramos las diferencias entre la técnica individual de las esquiadoras analizadas. Este estudio nos confirma la importancia del entrenamiento en situación real de competición (en cuanto a material, características pista de entrenamiento, etc.

Quasi-exact solvability beyond the SL(2) algebraization

We present evidence to suggest that the study of one dimensional quasi-exactly solvable (QES) models in quantum mechanics should be extended beyond the usual \sla(2) approach. The motivation is twofold: We first show that certain quasi-exactly solvable potentials constructed with the \sla(2) Lie algebraic method allow for a new larger portion of the spectrum to be obtained algebraically. This is done via another algebraization in which the algebraic hamiltonian cannot be expressed as a polynomial in the generators of \sla(2). We then show an example of a new quasi-exactly solvable potential which cannot be obtained within the Lie-algebraic approach.Comment: Submitted to the proceedings of the 2005 Dubna workshop on superintegrabilit

870 micron continuum observations of the bubble-shaped nebula Gum 31

We are presenting here a study of the cold dust in the infrared ring nebula Gum 31. We aim at deriving the physical properties of the molecular gas and dust associated with the nebula, and investigating its correlation with the star formation in the region, that was probably triggered by the expansion of the ionization front. We use 870 micron data obtained with LABOCA to map the dust emission. The obtained LABOCA image was compared to archival IR,radio continuum, and optical images. The 870 micron emission follows the 8 micron (Spitzer), 250 micron, and 500 micron (Herschel) emission distributions showing the classical morphology of a spherical shell. We use the 870 micron and 250 micron images to identify 60 dust clumps in the collected layers of molecular gas using the Gaussclumps algorithm. The clumps have effective deconvolved radii between 0.16 pc and 1.35 pc, masses between 70 Mo and 2800 Mo, and volume densities between 1.1x10^3 cm^-3 and 2.04x10^5 cm^-3. The total mass of the clumps is 37600 Mo. The dust temperature of the clumps is in the range from 21 K to 32 K, while inside the HII region reaches ~ 40 K. The clump mass distribution is well-fitted by a power law dN/dlog(M/Mo) proportional to M^(-alpha), with alpha=0.93+/-0.28. The slope differs from those obtained for the stellar IMF in the solar neighborhood, suggesting that the clumps are not direct progenitors of single stars/protostars. The mass-radius relationship for the 41 clumps detected in the 870 microns emission shows that only 37% of them lie in or above the high-mass star formation threshold, most of them having candidate YSOs projected inside. A comparison of the dynamical age of the HII region with the fragmentation time, allowed us to conclude that the collect and collapse mechanism may be important for the star formation at the edge of Gum 31, although other processes may also be acting.Comment: 15 pages, 10 figures. Accepted for publication in A&

New Algebraic Quantum Many-body Problems

We develop a systematic procedure for constructing quantum many-body problems whose spectrum can be partially or totally computed by purely algebraic means. The exactly-solvable models include rational and hyperbolic potentials related to root systems, in some cases with an additional external field. The quasi-exactly solvable models can be considered as deformations of the previous ones which share their algebraic character.Comment: LaTeX 2e with amstex package, 36 page

Numerical study of the aerodynamics of sound sources in a bass-reflex port

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The aim of this paper is to study the aerodynamics phenomena of a bass-reflex port that causes noise in the audible frequency range. After discarding structural and mechanical vibration issues, the hypothesis considered is that vortex shedding is the source of the noise. Experimental and numerical evidences of the vortex, an analysis of its noise and the similarities between real and simulated performance are presented. The numerically simulated cases with the original geometry are excited at different frequencies and with modifications of the port geometry. Likewise, the internal performance of an enclosure with a closed port was simulated. The simulations have been performed with axisymmetrical geometries using the open-source OpenFOAM® toolbox. Moreover, experimental measurements were carried out. First, acoustic signal experiments were done to analyse the response of the bass-reflex ports. Secondly, a structure vibration measurement was conducted in order to exclude the cabinet structure vibration as a source of the noise in question. A good agreement was found between numerical and experimental results, especially in the frequency band of the detected noise, i.e. the 1000–1500 Hz range. Despite no remarkable improvement being made with the geometry changes explored, the presented CFD approach has proved a useful and cost-effective tool to address this kind of phenomenon.Peer ReviewedPostprint (published version

Failure analysis of prestressed anchor bars

Three broken steel bars from a sewed crack in a dam are reported. The inspection of the fracture surfaces of the prestressed bars suggests that fractures were triggered by small cracks and by the inherent brittleness of the bars, as fracture toughness was about 40 MPa m1/2. The analysis of the failures shows that the usual design requirements for prestressing bars fail to warn against brittle failures if some damage exists. Some recommendations, based on the concept of damage tolerance, are suggested to avoid similar unfortunate incidents

Additional restrictions on quasi-exactly solvable systems

In this paper we discuss constraints on two-dimensional quantum-mechanical systems living in domains with boundaries. The constrains result from the requirement of hermicity of corresponding Hamiltonians. We construct new two-dimensional families of formally exactly solvable systems and applying such constraints show that in real the systems are quasi-exactly solvable at best. Nevertheless in the context of pseudo-Hermitian Hamiltonians some of the constructed families are exactly solvable.Comment: 11 pages, 3 figures, extended version of talk given at the International Workshop on Classical and Quantum Integrable Systems "CQIS-06", Protvino, Russia, January 23-26, 200

Eficacia de un programa para el tratamiento del sobrepeso y la obesidad no mórbida en atención primaria y su influencia en la modificación de estilos de vida

Introducción y Objetivos: la modificación de conductas no saludables es fundamental para tratar la obesidad. El objetivo de este estudio fue evaluar los efectos de un programa basado en dieta, ejercicio y apoyo psicológico en la modificación conductual de pacientes con sobrepeso y obesidad tratados en Atención Primaria. Métodos: 60 pacientes con sobrepeso grado II y obesidad grado I-II fueron incluidos en este ensayo piloto. Edad entre 18-50 años. Los pacientes recibieron un programa que combinaba educación nutricional, actividad física y apoyo psicológico. Formato grupal, periodicidad quincenal. Los principales resultados medidos al inicio y 6 meses fueron parámetros antropométricos (índice de masa corporal, porcentaje de masa grasa, perímetro cintura) y de estilos de vida usando el Cuestionario para la valoración de hábitos de vida relacionados con el sobrepeso y la obesidad. Consta de 5 dimensiones: contenido calórico de la dieta (CC), alimentación saludable (AS), ejercicio físico (EF), comer por bienestar psicológico (BP) y consumo de alcohol (CA). La mayor puntuación indica mejores hábitos para CC, AS y EF y peores para BP y CA. Resultados: al final de la intervención mejoraron las escalas CC (2,60± 0,5 vs 3,49± 0,7, p<0,001), EF (2,19± 0,9 vs 3,17± 1,0, p<0,001) y AS (3,04± 0,4 vs 3,43± 0,4, p<0,05) del cuestionario; CA (3,98± 0,7 vs. 4,25± 0,7, p<0,05) y BP (2,82± 1,0 vs. 3,34± 0,7, p<0,001) empeoraron. Conclusión: el programa basado en moderada restricción de la dieta, aumento de actividad física y apoyo psicológico puede mejorar parámetros antropométricos y estilos de vida en pacientes obesos tratados en un centro de Atención PrimariaBackground: Lifestyle intervention is fundamental for obesity treatment. The aim of this study was to evaluate the effects of a program focused on diet, exercise and psychological support on Lifestyle Modification in overweight and obese patients treated in Primary Health Care setting. Methods: 60 patients with grade II overweight and non-morbid grade I-II obesity were included in this pilot clinical trial. Ages ranged from18 to 50 years. They were provided with a program combining nutritional education, physical activity and psychological support. Subjects attended group sessions every 2 weeks. The main outcome measures at baseline and 6 months were body composition parameters (BMI, body fat percentage, waist circumference) and lifestyle intervention using the Questionnaire for the assessment of overweight and obesity related lifestyles at baseline and six months. This questionnaire yields an five dimensions: diet caloric intake (CC), healthy eating (AS), physical activity (EF), searching for psychological well-being eating (BP) and alcohol intake (CA). The higher score indicates better lifestyles for CC, AS, EF and worse for BP y CA. Results: At the end of the intervention the program achieved improvements in Questionnaire related lifestyles subscales: CC (2,60± 0,5 vs. 3,49± 0,7, p<0,001), EF (2,19± 0,9 vs. 3,17± 1,0, p<0,001) and AS (3,04± 0,4 vs. 3,43± 0,4, p<0,05); CA (3,98± 0,7 vs. 4,25± 0,7, p<0,05) and BP (2,82± 1,0 vs. 3,34± 0,7, p<0,001) has got worse. Conclusion: The Program focused on balanced and moderate energy-restricted diets, increased physical activity and psychological support may improve the anthropometric parameters and the Lifestyle intervention in obese patients treated in a primary healthcare center.Este proyecto ha sido becado por el Ministerio de Ciencia e Innovación, a través del Instituto de Salud Carlos III y la Subdirección General de Evaluación y Fomento de la Investigación, en el marco del «Subprograma de Proyectos de Investigación de Evaluación de Tecnologías Sanitarias e Investigación en servicios de salud». Convocatoria 2008 de ayudas de la Acción Estratégica en Salud, en el marco del Plan Nacional de I+D+I 2008-2011 (PI08/90357). Y por la Fundación MAPFRE, a través del programa de Ayudas a la Investigación (2009

The Potential Role of Everlasting Flower (Helichrysum stoechas Moench) as an Antihypertensive Agent: Vasorelaxant Effects in the Rat Aorta

Helichrysum stoechas (L.) Moench (H. stoechas) is a medicinal plant traditionally used in the Iberian Peninsula to treat different disorders such as arterial hypertension. The aim of this study was to investigate the vascular effects of a polyphenolic methanolic extract of H. stoechas, which has high antioxidant activity, and its mechanism of action. Isometric myography studies were performed in an organ bath with rat aortic rings with intact endothelium. The H. stoechas extract produced vasorelaxation in the aortic rings that were precontracted by phenylephrine or KCl. L-NAME and Rp-8-Br-PET-cGMPS but not indomethacin or H-89; it also reduced the relaxant response evoked by H. stoechas extract on the phenylephrine-induced contractions. H. stoechas extract reduced the response to CaCl2 similar to verapamil and reduced the phenylephrine-induced contractions comparable with heparin. TRAM-34, apamin and glibenclamide reduced relaxation induced by the H. stoechas extract. The combination of L-NAME+TRAM-34+apamin almost completely inhibited the H. stoechas-induced effect. In conclusion, the relaxant effect of the H. stoechas extract is partially mediated by endothelium through the activation of the NO/PKG/cGMP pathway and the opening of Ca2+-activated K+ channels. Furthermore, the decrease in the cytosolic Ca2+ by the inhibition of Ca2+ influx through the L-type Ca2+ channels and by the reduction of Ca2+ release from the sarcoplasmic reticulum via the IP3 pathway is also involved. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Differential hippocampal response to chronic alcohol consumption of young adult and mature adult rats

AIMS Early ethanol consumption could be a risk factor for young brain integrity and its maturation, and also for the development of addictive behaviors in adulthood. Neuronal nitric oxide synthase (nNOS) expressing neurons are specifically located in the subgranular layer (SGL) of dentate gyrus and may be relevant for hippocampal neurogenesis. The focus of this work is aimed to determine local changes in the nNOS-like immunoreactive (nNOS-LIR) cell populations of the SGL after chronic ethanol exposure in young adult and mature adult rats. METHODS We used the nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase (NADPH-d) reaction as a qualitative marker of nNOS enzyme activity. We also analyzed the nNOS-LIR cell density by the nNOS immunocytochemistry in order to compare these two methods of labeling. Dorsal striatum (CPu) was also analyzed in order to compare two neural areas with high nNOS-LIR cell density. RESULTS The young adult group showed less hippocampal NADPH-d(+) cell density than the mature adult group. Interestingly, the NADPH-d(+) cell density was increased in the SGL of the young adult ethanol-treated group, whereas it decreased in the mature adult ethanol-treated group, when compared with their respective controls. No change was observed in any of the groups for the hippocampal nNOS-LIR cell density and no differences could be established in CPu for nNOS-LIR and NADPH-d(+) cell densities in any of the groups studied. CONCLUSION The NADPH-d expression is affected by chronic ethanol exposure in opposite ways between both age groups studied. Further studies are needed to evaluate the relative importance of these findings, especially when considering human subject