Esbozo de marco conceptual para el estudio del cambio en las organizaciones universitarias, con especial consideración del caso argentino

El objetivo del trabajo es ofrecer un conjunto de herramientas teóricas para el análisis del cambio en los SES, con especial consideración del caso de las universidades argentinas. La perspectiva que lo anima es el producto de la combinación de elementos de la teoría organizacional -tanto en sus versiones generales como en particular las referidas y pensadas para el estudio de las organizaciones universitarias- con el espíritu del análisis estratégico. Si el análisis estratégico supone actores racionales en busca de la maximización de su propio beneficio o interés, la teoría organizacional, al menos en las versiones que se recogen aquí, permite dar cuenta de la identidad de esos actores y, consecuentemente, del proceso de conformación de los intereses que aquél asume como supuestos. Además de su función en la explicación de la identidad de los actores, los elementos de la teoría organizacional que aquí se rescatan permiten ordenar y comprender el escenario en que ellos intervienen

Perfil del jugador de rugby a partir de un screening de movimiento funcional como herramienta de prevención

En la última década numerosos trabajos de investigación científica han logrado dejar en claro la ventajas generadas a partir del entrenamiento de las capacidades condicionales de manera funcional, dejando atrás las tendencias en donde los patrones fundamentales de movimiento humano quedaban fuera del análisis del rendimiento deportivo. El interés que ha despertado en nuestro equipo de trabajo, como readaptadores del movimiento, nos lleva a indagar bajo esta perspectiva y las metodologías implementadas para su programación. El presente artículo intenta dar una perspectiva de trabajo a partir del desarrollo de un perfil preventivo, desarrollado en base a un screening funcional de movimiento. Utilizamos para ello, una matriz de datos diseñada a partir del análisis del movimiento su correcta y eficiente ejecución. Como contrapartida esto nos facilita la detección de patrones de movimiento afuncionales, patrones que no supongan una ejecución eficaz, que devendrá en puntos débiles para nuestros deportistas. Nuestro Universo de investigación son jugadores del Plantel Superior de clubes de Rugby de la ciudad de La Plata, que se desempeñan en la Primera División de la Unión de Rugby de Buenos Aires. La matriz de datos presentada utiliza como bases el Functional Movement Screen, diseñado por el fisioterapeuta Gray Cook y el Dr. Lee Burton, con adaptaciones desarrolladas, para objetivar datos en el análisis de los patrones biomecánicos humanos, con respecto al desempeño funcional y la prevención de lesiones deportivas

Osmium isotope composition of ODP Hole 121-758A

This study presents osmium (Os) isotope and elemental data for cleaned planktic foraminifera, authigenic Fe-Mn oxyhydroxides and pelagic carbonate host sediments from ODP site 758 in the southernmost reaches of the Bay of Bengal. The Os in the bulk sediments appears to be dominantly hydrogeneous (sourced by carbonate and Fe-Mn oxyhydroxide), but variations in this particular core are controlled by the presence of volcanic ash. Fe-Mn oxyhydroxide leachates (of the bulk sediments) from Holocene samples also yield an Os isotope composition close to that of seawater, but the record diverges from that of foraminifera at a depth corresponding to the oxic/post-oxic boundary, suggesting diagenetic mobilization of Os at depths below this. Holocene planktic foraminifera, cleaned using oxidative-reductive techniques, also give Os isotope compositions indistinguishable from modern seawater, but the record obtained for the past 150 kyr shows strong covaraitions of 187Os/188Os with both the local and global oxygen isotope record, with less radiogenic Os isotope compositions during glacial intervals. These results indicate that foraminifera provide a robust record of seawater Os isotope compositions, and comparison of the data obtained here with records from the other major oceans demonstrate global changes in 187Os/188Os over this time interval, while the covariation with oxygen isotopes suggest a process controlling the Os isotope composition that is in phase with global climate cycles. Global excursions to relatively unradiogenic 187Os/188Os during glacial intervals are consistent with decreased input of radiogenic continental material, reflecting cooler temperatures and reduced continental runoff. Modelling indicates that the shift to unradiogenic values during glacial intervals could be caused by an ~30% decrease in the global river flux, with an ~5% change in river composition. If the residence time of Os in the oceans is ~5 ka then the post-glacial recovery to present-day seawater values is consistent with a corresponding increase in the river flux of around 30%. However, if the residence time of Os is closer to 40 ka, as is suggested by the global river flux, then this demands either significant changes in both the riverine Os flux and composition of around 40% and 30%, respectively, that closely follow the oxygen isotope record, or else a short-lived post-glacial pulse of weathering some 75% greater than the steady-state flux. In either case, these results clearly indicate that climatic changes affect both the flux and composition of weathered material delivered to the oceans on glacial-interglacial timescales.

Neodymium isotope composition of planktonic foraminifera from ODP Hole 121-758A

This study presents neodymium isotope and elemental data for cleaned planktonic foraminifera from ODP site 758 in the southernmost reaches of the Bay of Bengal in the north-east Indian Ocean. Cleaning experiments using oxidative-reductive techniques suggest that diagenetic Fe-Mn oxyhydroxide coatings can be effectively removed, and that the measured Nd isotope composition reflects the composition of seawater from which the foraminiferal calcium carbonate was precipitated. Modern core-top Pulleniatina obliquiloculata and Globorotalia menardii give epsilon-Nd values of 310.12 +/- 0.16 and 310.28 +/- 0.16, respectively, indistinguishable from recent direct measurements of surface seawater in this area. A high-resolution Nd isotope record obtained from G. menardii for the past 150 kyr shows systematic variations (Delta epsilon-Nd = 3) on glacial-interglacial timescales. The timing of those variations shows a remarkable correspondence with the global oxygen isotope record, which suggests a process controlling the Nd isotope composition that responds in phase with global climate cycles. Palaeoclimate reconstruction indicates that during the last glacial maximum changes in monsoon circulation resulted in a reduction in rainfall over the Indian subcontinent, and a decrease in the flux of river water delivered to the Bay of Bengal. Thus, changes in the riverine input of Nd, a change in either flux or composition, most likely caused the isotope variations, although changes in dust source or local ocean circulation may have also played a role. These results clearly establish a link between climate change and variations in radiogenic isotopes in the oceans, and illustrate the potential of Nd isotopes in foraminifera for highresolution palaeoceanographic reconstruction.

Tab. 3: Concentrations of selected chemical species at various depths in Ace Lake

This article reviews the history, chemical stratification, biology and biogeochemistry of Ace Lake, which is one of the many marine-derived meromictic (permanently stratified) lakes in the Vestfold Hills, Eastern Antarctica. The lake has an area of 18 ha, a maximum depth of 25 m, and a salinity range from 7 to 43 g l**-1. The lake mixes to a depth of 7 m in late winter as a result of brine freeze out during ice formation. Deeper mixing is precluded by a sharp halocline. The water beneath 12 m is permanently anoxic, The lake was formed approximately 10,800 yr BP as the polar ice cap melted. Sea level rise 7,800 yr BP resulted in invasion of seawater into the initially freshwater lake. Subsequently, sea level dropped, and the now saline lake became isolated from the ocean. The biota of the lake was derived from species trapped when the connection between the lake and the ocean was cut off. The oxic zone above 12 m supports a relatively simple community which includes microbial mats, four major species of phytoplankton (including a picocyanobacterium), two copepod species, and a variety of heterotrophic flagellates and ciliates. The anoxic zone contains populations of photosynthetic sulfur, sulfate reducing, fermentative and methanogenic bacteria, which combine to remineralise organic carbon which sediments from the upper waters. Research on the physics, biology and chemistry of Ace Lake has contributed significantly to knowledge of Antarctic meromictic lakes.