Horizontal profiles of longwave and shortwave radiation components over sea ice near Barrow, Alaska during the 2011 melt

An integrated instrument package for measuring and understanding the surface radiation budget of sea ice is presented, along with results from its first deployment. The setup simultaneously measures broadband fluxes of upwelling and downwelling terrestrial and solar radiation (four components separately), spectral fluxes of incident and reflected solar radiation, and supporting data such as air temperature and humidity, surface temperature, and location (GPS), in addition to photographing the sky and observed surface during each measurement. The instruments are mounted on a small sled, allowing measurements of the radiation budget to be made at many locations in the study area to see the effect of small-scale surface processes on the large-scale radiation budget. Such observations have many applications, from calibration and validation of remote sensing products to improving our understanding of surface processes that affect atmosphere-snow-ice interactions and drive feedbacks, ultimately leading to the potential to improve climate modelling of ice-covered regions of the ocean. The photographs, spectral data, and other observations allow for improved analysis of the broadband data. An example of this is shown by using the observations made during a partly cloudy day, which show erratic variations due to passing clouds, and creating a careful estimate of what the radiation budget along the observed line would have been under uniform sky conditions, clear or overcast. Other data from the setup's first deployment, in June 2011 on fast ice near Point Barrow, Alaska, are also shown; these illustrate the rapid changes of the radiation budget during a cold period that led to refreezing and new snow well into the melt season.

Transformaciones territoriales y problemas ambientales en la zona de los Esteros del Iberá

Fil: Vallejos, Víctor Hugo. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Entrenamiento y fisiología del ejercicio en la pubertad : Análisis de las creencias actuales mas frecuentes

El presente trabajo forma parte de la especialización en fisiología del ejercicio de la Universidad Nacional de La Plata, Argentina. En este estudio se pudo comprobar la existencia de diversas creencias en cuanto a las prácticas de entrenamientos físico-deportivos en edades puberales. En primer lugar se seleccionaron algunas de las creencias consideradas mas relevantes en cuanto al impacto que pudieran ocasionar en los jóvenes practicantes. Posteriormente se confecciono un instrumento de recolección de datos mediante el cual se encuesto a 126 profesionales del ejercicio físico. Se determinaron las creencias mas prevalentes en la población objeto del estudio y se realizo una revisión de la documentación a fin de establecer la veracidad o falsedad de cada una de ellas. Las 8 creencias seleccionadas se clasificaron en creencias con sustento científico consideradas verdaderas y creencias sin sustento científico, consideradas mitos