918 resultados para Perforadoras de roca
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Suplemento al Diario de Valencia del dia 13 de septiembre de 1794
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Hay un ejemplar encuadernado con: Romans, y coloqui nou, pera divertir el humor y desterrar la melancolia, yà que no tenim dinès ... (NP849.91/3085).
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En la literatura se ha descrito el perfil antropométrico y la respuesta psicofisiológica en escalada deportiva en roca, pero hasta la fecha, no se habían analizado las diferencias existentes entre sus principales modalidades. El objetivo de la presente tesis fue describir las características antropométricas del escalador de competición y comprobar la existencia de diferencias entre los participantes de distintas modalidades, así como analizar la respuesta psico-fisiológica durante la ejecución de un búlder y una vía, además de evaluar las diferencias entre su realización a vista o tras un ensayo. Para ello, efectuamos dos estudios diferentes: en el primero participaron voluntariamente 61 hombres y 18 mujeres, participantes en cuatro pruebas del circuito nacional de competición de escalada durante el año 2009, tres de ellas de la modalidad de dificultad a vista y una de búlder. Se realizaron mediciones antropométricas, prueba de fuerza de prensión manual antes y después de competir, y se cumplimentó un cuestionario donde se evaluaba la percepción del esfuerzo y la experiencia deportiva. En el segundo estudio, 23 escaladores, 15 hombres y 8 mujeres, divididos en tres grupos en función de su nivel de rendimiento, realizaron de manera voluntaria distintas pruebas durante tres días separados entre sí al menos 48 horas. El primer día rellenaron un cuestionario sobre su experiencia deportiva y nivel de rendimiento, fueron pesados, tallados y sometidos a un escáner de cuerpo completo en densitómetro con objeto de medir la composición corporal. El segundo día realizaron previo calentamiento, un búlder a vista y, tras un descanso de 15 minutos, escalaron una vía a vista acorde con su nivel. El tercer día, después de calentar y disponer de 20 minutos para ensayarlo, repitieron la escalada del búlder. Tras un descanso de 15 minutos y 20 minutos de ensayo, realizaron un segundo intento a la vía. Se registraron los valores en la respuesta cardiorrespiratoria, se obtuvieron muestras de lactato en sangre del lóbulo de la oreja y se realizaron pruebas de fuerza de prensión manual antes y después de la escalada. También se pasó un cuestionario para medir la ansiedad y autoconfianza así como el esfuerzo percibido. Los resultados no mostraron diferencias antropométricas significativas entre los participantes en competiciones de búlder y los que participaron en competiciones de escalada de dificultad a vista. Se dieron diferencias en la pérdida de fuerza antes y después de escalar entre dichos participantes. Las mujeres obtuvieron menor fuerza de prensión manual que los hombres pero la misma pérdida de fuerza entre el instante antes de competir y el posterior. La respuesta fisiológica durante la ejecución del búlder fue menor que la obtenida durante la ejecución de la vía. Hubo pérdida de fuerza de prensión manual entre el instante anterior y el posterior a ejecutar la vía, pero no al hacer el búlder. Sin embargo, no se dieron diferencias en la ansiedad y la autoestima provocada por ambas modalidades, por lo que deducimos que la ejecución de un búlder y una vía presentan una respuesta fisiológica distinta. Proponemos que la respuesta está relacionada, sobre todo, con las variables de ejecución, de tal manera que a mayor distancia y/o tiempo recorrido en la escalada, mayor será la contribución anaeróbica al esfuerzo y la fatiga manifestada como pérdida de fuerza que, en el caso del búlder, fue mínima o inexistente. En el segundo intento, tras un ensayo de 20 minutos en el búlder, se consiguió mejorar el rendimiento respecto al primer intento, que se manifestó con un aumento en la distancia recorrida. Sin embargo, en la vía no se dieron diferencias entre ambos intentos, ni en la ejecución, ni en la respuesta fisiológica, ni en la ansiedad, ni siquiera en la fuerza de prensión manual. ABSTRACT It has been described in the literature the anthropometric profile and psychophysiological response in rock climbing, but so far not been analyzed differences between its main modalities. The aim of this thesis was to describe the anthropometric characteristics of the climber competitor and check for differences between participants of different modalities and to analyze the psycho-physiological response during the execution of a boulder and a route also to assess differences between on sight and redpoint attempts. We made two different studies: in the first 61 men and 18 women who attended four competitions of national climbing circuit in 2009, three of them on-sight difficulty competitions and a boulder competition participated voluntarily. Anthropometric measurements, a hand grip strength test before and after competing were registered for each climber, and a questionnaire which assessed perception of effort and the climbing experience was fulfilled. In the second study, various tests were conducted on 23 volunteer climbers, 15 men and 8 women, during three days separated for, at least, 48 hours of resting, divided into three groups according to their performance. The first day, climbers completed a questionnaire on their experience and performance level. It was recorded weight, height and they underwent a full body scan densitometer in order to measure body composition. The second day, after previous warming-up, they climbed a boulder on sight and, after a break of 15 minutes, climbed a route on-sight according to their level. The third day, after warming-up and have 20 minutes to try it, they repeated the bouldering climbing. After a break of 15 minutes and 20 minutes of essaying, they made a second attempt at the route. Values in the cardiorespiratory response were recorded, blood lactate samples were obtained from earlobe, and hand grip strength was tested before and after the climb. They also filled a questionnaire to measure anxiety and self-confidence and perceived exertion. The results showed no significant anthropometric differences between participants in bouldering competitions and participants in competitions on-sight difficulty climbing. There were found differences in strength loss before and after climbing between those participants. Women had less hand grip strength than men but the same loss of strength between the records carried out before and after competing. The physiological response recorded for boulder climbing was lower than the obtained for the route. There was loss of hand grip strength between the time before and after running the route but not for bouldering. However, there were no differences in anxiety and self-esteem caused by both modalities, so we conclude that the implementation of a boulder and a route have different physiological responses. We think that this response is mainly related to performance variables, as a greater distance and/or travel time on the climb, the higher the anaerobic contribution to the effort and fatigue as manifested by loss of strength in the case of the boulder was minimal or nonexistent. In the second attempt after 20 minutes in the boulder better performance was achieved on the first attempt, which was manifested by an increment of climbing distance. However, there were the differences in the route between the two attempts, either in execution or in the physiological response, or anxiety, or even in hand grip strength.
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For nearly 200 years since their discovery in 1756, geologists considered the zeolite minerals to occur as fairly large crystals in the vugs and cavities of basalts and other traprock formations. Here, they were prized by mineral collectors, but their small abundance and polymineralic nature defied commercial exploitation. As the synthetic zeolite (molecular sieve) business began to take hold in the late 1950s, huge beds of zeolite-rich sediments, formed by the alteration of volcanic ash (glass) in lake and marine waters, were discovered in the western United States and elsewhere in the world. These beds were found to contain as much as 95% of a single zeolite; they were generally flat-lying and easily mined by surface methods. The properties of these low-cost natural materials mimicked those of many of their synthetic counterparts, and considerable effort has made since that time to develop applications for them based on their unique adsorption, cation-exchange, dehydration–rehydration, and catalytic properties. Natural zeolites (i.e., those found in volcanogenic sedimentary rocks) have been and are being used as building stone, as lightweight aggregate and pozzolans in cements and concretes, as filler in paper, in the take-up of Cs and Sr from nuclear waste and fallout, as soil amendments in agronomy and horticulture, in the removal of ammonia from municipal, industrial, and agricultural waste and drinking waters, as energy exchangers in solar refrigerators, as dietary supplements in animal diets, as consumer deodorizers, in pet litters, in taking up ammonia from animal manures, and as ammonia filters in kidney-dialysis units. From their use in construction during Roman times, to their role as hydroponic (zeoponic) substrate for growing plants on space missions, to their recent success in the healing of cuts and wounds, natural zeolites are now considered to be full-fledged mineral commodities, the use of which promise to expand even more in the future.
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Embora os escamados sejam comumente encontrados em sítios fossilíferos cenozóicos sul−americanos, materiais esqueléticos completos são raros. Apenas alguns poucos exemplares assim foram registrados, com a maioria dos achados representando materiais fragmentários de crânio e mandíbulas ou vértebras isoladas. Dentre as localidades provedoras de vertebrados fósseis na América do Sul, a Formação Chichínales se destaca pela recente descoberta, em seus sedimentos, de um crânio quase completo de um lagarto teiídeo previamente desconhecido. Dada a fauna associada, a idade da formação é definida como Mioceno Temprano (Colhuehuapense). No presente estudo, conclui−se, através de uma análise filogenética contendo 39 espécies viventes e fósseis de escamados e 149 caracteres osteológicos, que este material pertence a uma nova espécie do gênero contemporâneo Callopistes. Uma descrição morfológica detalhada do fóssil, obtida através de análises estereoscópicas e de microtomografia computadorizada de alta resolução (CT Scan), também é apresentada. A matriz morfológica foi analisada com o auxílio do software TNT Versão 1.1, seguindo o princípio de máxima parcimônia, com todos os caracteres tratados com a mesma pesagem, resultando em quatro árvores igualmente parcimoniosas, que foram então utilizadas para a construção de uma árvore de consenso estrito. Em todas as quatro árvores, o novo táxon posicionou−se dentro da família Teiidae como um membro do clado formado pelas demais espécies viventes de Callopistes. Entretanto, não foi possível estabelecer uma relação de grupo−irmão inequívoca entre as duas espécies de Callopistes presentes na análise e o fóssil. A atual distribuição das duas espécies viventes de Callopistes e a localidade de onde foi recuperado o fóssil em estudo indicam que esse gênero possuía uma distribuição muito mais ampla no passado, chegando a áreas patagônicas cis−Andinas, diferentemente das áreas trans−Andinas de altitude onde as duas espécies atuais estão restritas
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La Cueva del Rull se encuentra en el sector nororiental de la Cordillera Bética, en el denominado Prebético Externo de Alicante (Azema 1977). Regionalmente, la zona de estudio está dominada por la dinámica compresiva de los materiales calizos existentes (Cretácico Superior) afectados, desde el Mioceno Medio y durante el Mioceno Superior, por diversos movimientos tectónicos a partir de los cuales se origina la Depresión de la Vall d'Ebo. Esta fosa tectónica, cuyos bordes norte y sur quedan delimitados por fallas normales con dirección aproximada E-O, está rellena por materiales rudíticos de edad Mioceno Superior, predominantemente conglomeráticos, de espesor variable (decenas a más de 100 metros), localmente plegados y depositados sobre margas de facies “tap” (margas mal estratificadas de carácter arcillo-limoso, desagregadas y de color blanquecino en superficie, cuya edad se atribuye al Mioceno Medio).
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Mode of access: Internet.
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Certifica la copia Antonio Martínez Salazar.
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Mode of access: Internet.
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Fil: Ramírez, Ana Julia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.
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Fil: Ramírez, Ana Julia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.
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Fil: Ramírez, Ana Julia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.