6,633 research outputs found

    Semantic Variation in Online Communities of Practice

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    Differences in kicking velocity and kicking deficit in young elite soccer players

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    El objetivo de este estudio fue examinar la evolución del rendimiento máximo de golpeo de balón a lo largo de la edad en futbolistas jóvenes de élite. Un total de 175 fueron divididos en 11 grupos edad (U-9 hasta U-19), además del equipo filial del club (U-23). Se registró la velocidad máxima de golpeo con la pierna dominante y no dominante mediante radar. El déficit de golpeo fue calculado para comparar el rendimiento entre ambas piernas. La velocidad máxima de golpeo aumenta progresivamente de forma significativa desde U-9 hasta U-16 con la pierna dominante y hasta U-18 con la no dominante, y sigue aumentando de forma no significativa hasta U-23. La etapa con mayor incremento de la velocidad de golpeo fue entre U-13 y U-16. Existe un déficit de golpeo con la pierna no dominante y sus valores permanecen estables (9.43%-18.18%) sin cambios significativos desde U-9 hasta U-23The purpose of this current study was to examine the age-related differences in kicking performance with both legs in 175 youth soccer players. Players from the development programme of a professional club were grouped according to their respective under-age team (U-9 to U-18), in addition to the club’s second team (U-23). Maximal kicking velocity with the preferred and non-preferred leg was recorded using a Doppler radar gun. Kicking deficit was calculated to compare side-to-side performance. Maximal kicking velocity improved progressively from the U-9 to U-16 age groups for the preferred leg and from U-16 to U-18 for the non-preferred leg, and continued to improve moderately but non-statistically significant until U-23. The stage of greatest kicking velocity development was between 13 and 16 years of age. There is a kicking deficit with the non-preferred leg and its values remain steady (9.43%-18.18%) without significant changes in players from U-9 to U-23 categorie

    Fístula arteriovenosa postraumática: tratamiento endovascular. Revisión de la literatura y presentación de un caso clínico

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    ResumenLas fístulas arteriovenosas en la cabeza y el cuello son entidades poco frecuentes. La mayoría es secundaria a heridas penetrantes por arma blanca. Se describe el tratamiento exitoso mediante cirugía endovascular de una fístula postraumática tras una herida penetrante entre la arteria maxilar interna izquierda y la vena yugular externa. A través de este caso clínico y la revisión de la literatura se ilustran las causas, manifestaciones, estudio radiológico y tratamiento de una fístula postraumática entre la arteria maxilar interna y la vena yugular externa. A través de este caso clínico se demuestra la utilidad de los procedimientos endovasculares en el tratamiento de estas complicaciones.AbstractTraumatic arteriovenous fistulas of the head and neck region are uncommon. The majority are due to penetration of blunt injury. We describe a successful endovascular treatment of a posttraumatic fistula between the left maxillary artery and the external jugular vein due to a penetration injury. This case and a review of the literature illustrate the causes, manifestations, image studies and treatment for a posttraumatic fistula between the maxillary artery and the external jugular vein. This case demonstrate the utility of endovascular treatment of head and neck injuries complications

    Protocol for a sequential, prospective metaanalysis to describe coronavirus disease 2019 (COVID-19) in the pregnancy and postpartum periods.

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    We urgently need answers to basic epidemiological questions regarding SARS-CoV-2 infection in pregnant and postpartum women and its effect on their newborns. While many national registries, health facilities, and research groups are collecting relevant data, we need a collaborative and methodologically rigorous approach to better combine these data and address knowledge gaps, especially those related to rare outcomes. We propose that using a sequential, prospective meta-analysis (PMA) is the best approach to generate data for policy- and practice-oriented guidelines. As the pandemic evolves, additional studies identified retrospectively by the steering committee or through living systematic reviews will be invited to participate in this PMA. Investigators can contribute to the PMA by either submitting individual patient data or running standardized code to generate aggregate data estimates. For the primary analysis, we will pool data using two-stage meta-analysis methods. The meta-analyses will be updated as additional data accrue in each contributing study and as additional studies meet study-specific time or data accrual thresholds for sharing. At the time of publication, investigators of 25 studies, including more than 76,000 pregnancies, in 41 countries had agreed to share data for this analysis. Among the included studies, 12 have a contemporaneous comparison group of pregnancies without COVID-19, and four studies include a comparison group of non-pregnant women of reproductive age with COVID-19. Protocols and updates will be maintained publicly. Results will be shared with key stakeholders, including the World Health Organization (WHO) Maternal, Newborn, Child, and Adolescent Health (MNCAH) Research Working Group. Data contributors will share results with local stakeholders. Scientific publications will be published in open-access journals on an ongoing basis.post-print641 K
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