Influence of coach encouragement on technical demand of an small-sided games in football-7.

El objetivo del presente estudio ha sido analizar el efecto de la motivación del entrenador sobre la demanda técnica de un juego reducido (JR) 3 contra 3, realizado por futbolistas de categoría alevín, observando el nivel de aprendizaje técnico adquirido a través de estas tareas. Se han cuantificado el número de acciones técnicas que se producen en un JR de 3 contra 3 sin intervención del entrenador (JRSIE) y las que se producen en el mismo JR con la intervención del entrenador (JRCME). Se ha realizado en cada una de las 4 sesiones del programa de entrenamiento con JR dos test de valoración del dominio técnico en situaciones pre y post sesión. Los resultados confirman que aparecen diferencias en el número de acciones técnicas que el jugador realiza durante el JR, siendo significativamente mayor en el JRCME, generándose además mayor nivel de aprendizaje

Nonadiabatic forces in ion-solid interactions: the initial stages of radiation damage

The Born-Oppenheimer approximation is the keystone for molecular dynamics simulations of radiation damage processes; however, actual materials response involves nonadiabatic energy exchange between nuclei and electrons. In this work, time dependent density functional theory is used to calculate the electronic excitations produced by energetic protons in Al. We study the influence of these electronic excitations on the interatomic forces and find that they differ substantially from the adiabatic case, revealing a nontrivial connection between electronic and nuclear stopping that is absent in the adiabatic case. These results unveil new effects in the early stages of radiation damage cascades

Caracterización y evaluaciçón de la capacidad de uso de los suelos de la comarca de "El Aljarafe" (Sevilla)

8 páginas, 5 tablas y 7 referencias. Comunicación presentada en las Actas del VII Congreso Nacional de Química (Química Agrícola y Alimentaria/2). Sevilla (España). 12 al 17 de Octubre de 1987. Vol. 1: "El suelo: fertilidad y fertilizantes". "La planta: aspectos bioquímicos y fisiológicos". "Protección vegetal"The soils of "El Aljarafe" region (Seville) are studied. As a result, different soils are found and classified into 19 taxonomic units of "Soil Taxonomy" (1975) System. Also. their land capability to relative, use, their erosion hazard and their ability for irrigation purposes, are evaluted. A soil map finally, to scale 1/50.000, with the results of the evaluation, is added.Peer reviewe

Influencia del entrenador en la demanda técnica de un juego reducido en fútbol-7

The aims of this study were to examine the effect of coach encouragement in the technical demand of small-sided games 3-a-side in young football players. In this study were analysed also the level of learning acquired for the players.The numbers of technical actions doing during small-sided games 3-a sided with and without coach encouragement was counted during every session of the program. Specific technical test was used to identify the learning level acquired. In base of the results of this study, the coach encouragement should consider as an important factor for the SSG design and for the technical training of the young player.El objetivo del presente estudio ha sido analizar el efecto de la motivación del entrenador sobre la demanda técnica de un juego reducido (JR) 3 contra 3, realizado por futbolistas de categoría alevín, observando el nivel de aprendizaje técnico adquirido a través de estas tareas.Se han cuantificado el número de acciones técnicas que se producen en un JR de 3 contra 3 sin intervención del entrenador (JRSIE) y las que se producen en el mismo JR con la intervención del entrenador (JRCME). Se ha realizado en cada una de las 4 sesiones del programa de entrenamiento con JR dos test de valoración del dominio técnico en situaciones pre y post sesión.Los resultados confirman que aparecen diferencias en el número de acciones técnicas que el jugador realiza durante el JR, siendo significativamente mayor en el JRCME, generándose además mayor nivel de aprendizaje

Jarava pseudoichu (Caro) F. Rojas

Alta GraciapublishedVersio

Descomposición de macrófitas en el arroyo Las Flores (Buenos Aires)

The macrophytes contribute significantly to the autochthonous primary production of the streams of the Buenos Aires province. Their biomass is partly exported, mainly during floods, and partly incorporated to the detritus pathway of the water bodies. The aim of this study is to determine the losses in weight and nitrogen along the process of decomposition of Lemna gibba and Ceratophyllum demersum, two of the dominant species in the Las Flores stream. A total of 40 bags with 4 g (fresh weight) of L. gibba and 10 g of C. demersum were set in two sites of the stream. Periodically, 4 samples of each species were redrawn, and the dry weight and total nitrogen concentration were determined. L. gibba lost 50% of its weight in 4 days, from then on and until the end of the incubation period (50 days) the weight kept approximately constant, fitted to a Hill’s function with a maximum rate of 0.158 day-1. The weight of C. demersum was almost stable until day 44, and at the end of the following 42 days it was observed that it had lost 62% of its initial weight, with a constant rate of k = 0.0203 day-1. In L. gibba essay, nitrogen concentration lowered from 3.4% to 2.4% in the first 48 hours, thus representing a 52% loss of the total nitrogen content of the plant. For C. demersum, nitrogen concentration decayed from 4.1% until 3.2%; by the end of the sampling, the total nitrogen content had reduced to 33.5% of the initial value. The results indicate that, given the quickness of the decomposition and nutrient release, an important part of the production can be incorporated to the material cycles of the stream before the plants are washed downstream during floods.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Descomposición de macrófitas en el arroyo Las Flores (Buenos Aires)

The macrophytes contribute significantly to the autochthonous primary production of the streams of the Buenos Aires province. Their biomass is partly exported, mainly during floods, and partly incorporated to the detritus pathway of the water bodies. The aim of this study is to determine the losses in weight and nitrogen along the process of decomposition of Lemna gibba and Ceratophyllum demersum, two of the dominant species in the Las Flores stream. A total of 40 bags with 4 g (fresh weight) of L. gibba and 10 g of C. demersum were set in two sites of the stream. Periodically, 4 samples of each species were redrawn, and the dry weight and total nitrogen concentration were determined. L. gibba lost 50% of its weight in 4 days, from then on and until the end of the incubation period (50 days) the weight kept approximately constant, fitted to a Hill’s function with a maximum rate of 0.158 day-1. The weight of C. demersum was almost stable until day 44, and at the end of the following 42 days it was observed that it had lost 62% of its initial weight, with a constant rate of k = 0.0203 day-1. In L. gibba essay, nitrogen concentration lowered from 3.4% to 2.4% in the first 48 hours, thus representing a 52% loss of the total nitrogen content of the plant. For C. demersum, nitrogen concentration decayed from 4.1% until 3.2%; by the end of the sampling, the total nitrogen content had reduced to 33.5% of the initial value. The results indicate that, given the quickness of the decomposition and nutrient release, an important part of the production can be incorporated to the material cycles of the stream before the plants are washed downstream during floods.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Descomposición de macrófitas en el arroyo Las Flores (Buenos Aires)

The macrophytes contribute significantly to the autochthonous primary production of the streams of the Buenos Aires province. Their biomass is partly exported, mainly during floods, and partly incorporated to the detritus pathway of the water bodies. The aim of this study is to determine the losses in weight and nitrogen along the process of decomposition of Lemna gibba and Ceratophyllum demersum, two of the dominant species in the Las Flores stream. A total of 40 bags with 4 g (fresh weight) of L. gibba and 10 g of C. demersum were set in two sites of the stream. Periodically, 4 samples of each species were redrawn, and the dry weight and total nitrogen concentration were determined. L. gibba lost 50% of its weight in 4 days, from then on and until the end of the incubation period (50 days) the weight kept approximately constant, fitted to a Hill’s function with a maximum rate of 0.158 day-1. The weight of C. demersum was almost stable until day 44, and at the end of the following 42 days it was observed that it had lost 62% of its initial weight, with a constant rate of k = 0.0203 day-1. In L. gibba essay, nitrogen concentration lowered from 3.4% to 2.4% in the first 48 hours, thus representing a 52% loss of the total nitrogen content of the plant. For C. demersum, nitrogen concentration decayed from 4.1% until 3.2%; by the end of the sampling, the total nitrogen content had reduced to 33.5% of the initial value. The results indicate that, given the quickness of the decomposition and nutrient release, an important part of the production can be incorporated to the material cycles of the stream before the plants are washed downstream during floods.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Trayectoria del ensamble de especies leñosas de la ribera del río Luján a cinco años de su desmonte.

El desmonte y el perfilado de la ribera del río Luján se realiza para acelerar el traslado del agua durante las crecidas. En dos sitios ribereños de la cuenca del río Luján (desmontados en 2014 y con desmonte planificado para 2020) se establecieron parcelas sobre dos transectos situados a 0 y a 10m de la orilla del río. En cada una de éstas se determinó el número de individuos de cada especie. Las distribuciones de abundancias relativas de especies de los distintos años se linealizaron y sólo fueron significativamente diferentes (ANOVA) las pendientes del año inmediatamente posterior al desmonte (2015). Al realizar un análisis de similitudes (ANOSIM) se distingue también la comunidad hallada antes del desmonte (2014) donde la especie dominante no era acacia negra sino arce. Se concluye que estas intervenciones facilitan el avance de la acacia negra en desmedro de las otras especies que constituyen el bosque ribereño en el río Luján

Estimación de la variación en la recarga del acuífero costero en Mar de las Pampas, Argentina, con base en cambios del uso del suelo

El objetivo de este trabajo es cuantificar la expansión de las áreas forestadas y su efecto sobre la disponibilidad del agua subterránea en la localidad de Mar de las Pampas, Partido de Villa Gesell, Argentina. A partir de imágenes satelitales y fotografías aéreas, mediante el mapeo manual detallado de los tipos de cobertura en la zona de estudio, se realizó un análisis multitemporal del uso del suelo para los años 1975, 1997 y 2014. Se calcularon balances hídricos a partir de datos de precipitación, teniendo en cuenta las propiedades hidrológicas características del terreno, para asignar un valor de recarga a cada tipo de cobertura. Los resultados indican una reducción de la recarga de un 26 % durante el periodo 1975-2014, lo cual deberá tenerse en cuenta para la planificación del uso sustentable del recurso hídrico subterráneo en una localidad actualmente en crecimiento