285 research outputs found

    Secuencia temporal en el swing de golf de jóvenes promesas

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    The golf swing is a skill which could be classified as a high velocity hitting where the main goal is that the head of the golf club reaches its maximum velocity at impact time. Ten golf swings executed by four young players were biomechanicaly analyze. Automatic capture with Vicon Oxford Metrics © was used. The absolute values of the linear velocities were higher at men that at women. At the interval analysis, the downswing presented less variation than the backswing. The analisis of the maximum timing sequence showed that depending on the gender they described different order. At men, the secuence started with the hip movement, followed by, left elbow, left shoulder and the club head. At women the hips and left elbow occurred simultaneously followed by the left shoulder and the club head. El swing en golf es una destreza que podríamos catalogar de golpeo de velocidad donde el objetivo es que la cara del palo alcance la máxima velocidad en el momento del impacto. Se han analizado biomecánicamente diez golpeos de cuatro jugadores promesas, mediante el sistema fotogrametría 3D Vicon Oxford Metrics © de captura automática. En primer lugar se ha podido comprobar que los valores absolutos de velocidades lineales eran mayores en los chicos que en los chicas. El análisis de las dos fases del swing indica que la fase de aceleración (downswing) presenta una variabilidad menor que el backwing. El análisis de la secuencia temporal de máximos alcanzados en los segmentos muestra cómo las aEcciones de los mismos siguen un orden diferente en función del género. La secuencia en los chicos empieza por el movimiento de caderas y sigue con el codo izquierdo, el hombro izquierdo y el palo; en las chicas, las caderas y el codo izquierdo actúan simultáneamente seguidos del hombro izquierdo y del palo.Peer Reviewe

    Cyanobacterial diversity in extreme environments in Baja California, Mexico: a polyphasic study

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    Cyanobacterial diversity from two geographical areas of Baja California Sur, Mexico, were studied: Bahia Concepcion, and Ensenada de Aripez. The sites included hypersaline ecosystems, sea bottom, hydrothermal springs, and a shrimp farm. In this report we describe four new morphotypes, two are marine epilithic from Bahia Concepcion, Dermocarpa sp. and Hyella sp. The third, Geitlerinema sp., occurs in thermal springs and in shrimp ponds, and the fourth, Tychonema sp., is from a shrimp pond. The partial sequences of the 16S rRNA genes and the phylogenetic relationship of four cyanobacterial strains (Synechococcus cf. elongatus, Leptolyngbya cf. thermalis, Leptolyngbya sp., and Geitlerinema sp.) are alsopresented. Polyphasic studies that include the combination of light microscopy, cultures and the comparative analysis of 16S rRNA gene sequences provide the most powerful approach currently available to establish the diversity of these oxygenic photosynthetic microorganisms in culture and in nature

    Valoración de la fuerza explosiva en esgrima

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    La fuerza explosiva es una capacidad física muy importante en la esgrima, por lo que su valoración resulta importante para el control y planificación del entrenamiento. El objetivo principal de este estudio fue valorar la fuerza explosiva general y específica en tiradores de alto nivel. Se aplicaron dos tests genéricos de fuerza explosiva (salto vertical sin contramovimiento –SJ-, y salto vertical con contramovimiento -CMJ-), y cuatro tests específicos (Fondo desde parado -F-, Fondo desde Saltos -FS-, Flecha desde parado -FL- y Flecha desde Saltos -FLS-) a 17 tiradores masculinos pertenecientes al equipo nacional español absoluto de esgrima. Se utilizaron dos plataformas de fuerza, una para cada apoyo. A partir de los datos de las fuerzas de reacción se obtuvieron las variables determinantes de la fuerza explosiva tales como el desplazamiento vertical (detente) o la velocidad horizontal de de despegue. Se observa que la batería de tests llevada a cabo proporciona, en un corto periodo de tiempo, una información de gran relevancia para el control y la planificación del entrenamiento con el objetivo de intentar optimizar el rendimiento de los deportistas. Se han encontrado diferencias significativas entre las fuerzas verticales máximas en cada apoyo en el salto vertical lo que puede estar asociado con asimetrías de la fuerza muscular.Explosive strength is one of the most important physical capacities in fencing. The evaluation of explosive strength is fundamental for the planning and control of the training program. The purpose of this study was to assess the general and specific explosive strength in 17 senior male fencers of the national Spanish team. They carried out general explosive strength tests: Squat Jump (SJ) and Counter Movement Jump (CMJ); and specific explosive strength tests: Lunge from static position (F), Lunge from bounces (FS), Flèche from static position (FL) and Flèche from bounces (FLS). From the information of the reaction forces there were obtained the determinant variables of the explosive strength, such as the vertical displacement or the takeoff horizontal speed. The results were obtained from two force platforms, one for each support. Results showed that the tests carried out provided, in a short time, relevant information to plan and control the training program in order to the improve athletes performance. Significant differences were found between the vertical maximal strength in each support in the vertical jump. These differences can be associated with asymmetries of the muscular force.Peer Reviewe

    Geochemical and geochronological constraints on the geologic evolution of the western Sonobari Complex, northwestern Mexico

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    In the southern Sierra Sonobari, NW Mexico, U-Pb and 40Ar/39Ar geochronology studies allowed to define the provenance and maximum depositional age of the Francisco Gneiss basement of the Sonobari terrane, and to establish the age of some magmatic events in that area. The youngest zircon cluster in paragneisses of the Francisco Gneiss indicates a maximum depositional age of 509 ± 29Ma. The main peaks of the relative probability plot yield ages of 1690 and 1404Ma with minor peaks at 1156, 921, and 517Ma. Major peaks suggest that the main source of sediments was the Paleo- and Mesoproterozoic crust of Laurentia. Orthogneiss from the Francisco Gneiss yields a U-Pb zircon upper intercept age of 248 ± 28Ma, which is interpreted as the crystallization age. Crosscutting dykes of metabasite yield an 40Ar/39Ar age of 67 ± 5Ma, which is interpreted as indicating cooling after either a latest Early Cretaceous orogenic event or Late Cretaceous contact metamorphism. Granodiorite intruding the Francisco Gneiss yields a U-Pb age of 64 ± 1Ma, which is interpreted as a magmatic age. The hornblende-plagioclase Macochin Gabbro yields 40Ar/39Ar isochron ages of 54 ± 10Ma and 47 ± 5Ma, which are interpreted as cooling ages after the gabbro intrusion. Geochemical data indicate that the mafic rocks of the Francisco Gneiss correspond to subalkaline basalts of tholeiitic affinity with concentrations of high field strength elements similar to oceanic basalts, suggesting an asthenospheric upper mantle source. However, according to the variation in Th/Yb and U/Yb, the amphibolites display a significant influence of the upper continental crust. The Macochin Gabbro also has a geochemical signature characteristic of subalkaline basalt with tholeiitic affinity, and high field strength elements similar to oceanic basalts. Tectonic discrimination diagrams and elemental distribution suggest that the mafic rocks of both the Francisco Gneiss and Macochin Gabbro were emplaced during rifting in a back-arc setting

    The prevalence of depression, anxiety and stress and their associated factors in college students

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    Aim: To estimate the prevalence of symptoms of depression, anxiety, stress and associated factors in a population of college students. Method: Cross-sectional study of psychological distress measured through the Depression, Anxiety and Stress Scale (DASS-21) in a sample of 1074 college students. Results: We found a moderate prevalence of depression (18, 4%), anxiety (23, 6%) and stress (34, 5%) symptoms in our study population. Being <21, having problematic Internet use behavior, smoking, presenting insomnia and having a low self-esteem were independently associated with symptoms of depression, anxiety and stress. Being a woman, living with their family, having a stable partner, consuming alcohol frequently and having poor nutritional habits were significantly associated with symptoms of stress; lacking a stable partner was significantly associated with depressive symptoms; and frequent consumption of alcohol was significantly associated with symptoms of anxiety. Conclusion: We found a moderate prevalence of depression, anxiety and stress symptoms in our population. Interventions aimed at promoting mental health among college students should be implemented

    Temperament and attachment as predictive factors for the risk of addiction to substances in adolescents.

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    Abstract: This study aims to relate the dimensions of temperament and attachment with the risk of addiction to substances in a group of 642 adolescents between 13 and 19 years old, and to assess which dimensions of these constructs acted as risk or protective factors. It also relates the two constructs between them. There was a positive correlation between the risk of addiction and the temperament dimension "Novelty seeking" and with those of attachment, "Self-sufficiency and parental resentment" and "Child trauma". The correlation was negative with "Persistence" (temperament) and "Security" (attachment). "Novelty seeking", "Family concern" and age, acted as risk factors; whereas “Security” in attachment was a factor of protection. The temperament and attachment profiles with a higher risk of addiction correlated with each other; they also correlated those with a low risk. Resumen: Temperamento y apego como factores predictivos para el riesgo de adicción a sustancias en adolescentes.Este estudio busca relacionar las dimensiones de temperamento y apego con el riesgo de adicción a sustancias en un grupo de 642 adolescentes de entre 13 y 19 años, y valorar qué dimensiones de estos constructos actúan como factores de riesgo o de protección. También se relacionan los dos constructos entre ellos. Hubo una correlación positiva entre el riesgo de adicción y la dimensión de temperamento “Búsqueda de novedad”, y con las de apego “Autosuficiencia y rencor hacia los padres” y “Trauma infantil”. La correlación fue negativa con “Persistencia” (temperamento) y “Seguridad” (apego). “Búsqueda de la novedad”, “Preocupación familiar” y edad, actuaron como factores de riesgo; mientras que la “Seguridad “en el apego fue un factor de protección. Los perfiles de temperamento y apego con riesgo más elevado de adicción correlacionaron entre ellos; también correlacionaron aquellos con un riesgo bajo.        

    Efficacy of antiemetic therapy in patients undergoing laparoscopic cholecystectomy

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    AbstractIntroductionA high incidence of postoperative nausea and vomiting has been observed in patients undergoing laparoscopic cholecystectomy (20–40%). This causes an increase in patient discomfort, a delay in recovery, and an increase in hospital stay.ObjectiveCompare the efficacy of ondansetron plus metoclopramide and ondansetron alone in the control of postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy.Material and methodsA comparative, prospective, experimental, longitudinal double blind study was performed with 30 patients programmed for laparoscopic cholecystectomy. The Apfel score was applied postoperatively. Patients were divided into two groups with 15 participants. Metoclopramide 10mg and ondansetron 4mg were administered in the first Group (A), and ondansetron 4mg in the second Group (B), after induction of anesthesia. Nausea and vomiting were evaluated for 24h postoperatively using a Likert scale.ResultsOf the patients who presented nausea, the condition was mild. The patient who presented vomiting, vomited only once. Neither group required rescue drugs. Regarding the Apfel score, there was no correlation between the percentage of stratified risk and the patients who presented postoperative nausea and vomiting.ConclusionsNo statistically significant difference was observed between ondansetron plus metoclopramide and ondansetron alone in patients subjected to laparoscopic cholecystectomy

    Efecto de la salinidad de una solución nutritiva en la papaya Maradol

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    Papaya (Carica papaya L.) is a crop of great economic importance. It is the fourth most produced tropical fruit in the world. The most substantial problems faced during its production are pests and diseases, which is why it has been planted under greenhouse conditions. However, it is required that the plants not be of great height not to need tall greenhouses. Therefore, this research aims to evaluate to the salinity effect and identify nutritive solutions that reduce plant height. The experimental design was completely randomized with four treatments and ten replications. The treatments were four concentrations of Steiner nutrient solution (50 %, 100 %, 150 %, and 200 %) in whose composition are anions (phosphate, nitrate, and sulfate) and cations (potassium, calcium, and magnesium), thus generating electrical conductivity of 1.0, 2.0, 3.0, and 4.0 dS/m, respectively. The variables evaluated were plant height, number of leaves, stem diameter, foliar area, chlorophyll a and b concentration, proline content, and foliar nutrient concentration. The nutrients comprise nitrogen, phosphorus, potassium, calcium, and magnesium. The analysis of variance indicated significant differences in all variables except magnesium concentration. As salinity increased, plant height, number of leaves, stem diameter, leaf area, phosphorus, potassium, and calcium decreased, but chlorophyll a and b concentration, proline content, and nitrogen increased. We conclude that Steiner nutrient solution with 4.0 dS/m (200 %) can reduce plant height  to grow it in greenhouses.La papaya (Carica papaya L.) es un cultivo de gran importancia económica, siendo la cuarta fruta tropical más producida en el mundo. Los problemas más fuertes que enfrenta su producción son la presencia de plagas y enfermedades, por lo que se ha optado por realizar su plantación en condiciones de invernadero. Sin embargo, se requiere que las plantas no sean de mucha altura o que los invernaderos sean muy altos. Por lo anterior, esta investigación tuvo como objetivo evaluar el efecto de salinidad para identificar soluciones nutritivas que permitan reducir la altura de la planta. El diseño experimental fue completamente al azar con cuatro tratamientos y diez repeticiones. Los tratamientos fueron cuatro concentraciones de solución nutritiva Steiner (50 %, 100 %, 150 % y 200 %) en cuya composición se encuentran aniones (fosfato, nitrato y sulfato) y cationes (potasio, calcio y magnesio), lo que genera conductividad eléctrica de 1,0, 2,0, 3,0 y 4,0 dS/m, respectivamente. Se evaluaron las variables altura de la planta, número de hojas, diámetro del tallo, área foliar, concentración de clorofila a y b, contenido de prolina y concentración foliar de nutrientes. Los nutrientes fueron nitrógeno, fósforo, potasio, calcio y magnesio. El análisis de varianza indicó diferencias significativas en todas las variables excepto en la concentración de magnesio. A medida que aumentó la salinidad, disminuyó la altura de la planta, el número de hojas, el diámetro del tallo y el área foliar, la concentración de fósforo, potasio y calcio, pero aumentó la concentración de clorofila a y b, el contenido de prolina y de nitrógeno. Se concluyó que la solución nutritiva Steiner con 4,0 dS/m (200 %), se puede utilizar para reducir la altura de la planta con el fin de cultivarla en invernadero

    Biomechanical analysis of the penalty-corner drag-flick of elite male and female hockey players

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    The aim of this study was to analyse the kinematic sequencing in the penalty-corner drag-flicks of elite male and female field hockey players of international calibre. Thirteen participants (one skilled male drag-flicker and six male and six female elite players) participated in the study. An optoelectronic motion analysis system was used to capture the drag-flicks with six cameras, sampling at 250 Hz. Select ground reaction force parameters were obtained from a force platform which registered the last support of the front foot. Twenty trials were captured from each subject. Both player groups showed significantly (p < 0.05) smaller ball velocity at release, peak angular velocity of the pelvis, and negative and positive peak angular velocities of the stick than the skilled subject. Normalised ground reaction forces of the gender groups were also smaller than that of the skilled drag-flicker. By comparing these players we established that the cues of the skill level are a wide stance, a whipping action (rapid back lift) of the stick followed by an explosive sequential movement of the pelvis, upper trunk and stick
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