929 resultados para Blast mats
Resumo:
Observations of hummock and string-like microrelief features were made in High Arctic hydric meadows. Thermal shearing of thick bryophyte mats, and subsequent roll back during spring flooding appears to be one way in which this topography is formed. Hummocky and non-hummocky (flat) meadows show distinct floristic differences which may in part be due to observed differences in temperature, nutrient concentrations and moisture relations.
Resumo:
Laminated diatom ooze samples collected during ODP Leg 177 were analysed using scanning electron microscope (SEM) and optical microscopy to test their potential as high-resolution records of Polar Front hydrography, surface production, and export. SEM analysis from two intervals, marine isotope stage (MIS) 29 and 12/11, respectively, recovered from 50°S in the Atlantic Ocean (ODP Site 1093, Hole A, sections 13H-4 0-18 cm and 23H-4 0-22 cm), show abundant and well-preserved Thalassiothrix antarctica mats, thought to be indicative of rapid export from the surface and deposition in the sediment. A preliminary analysis of laminae succession points to a possible annual couplet/triplet succession of laminae, and suggests exceptionally high local sedimentation rates of 57 and 80 cm/kyr for MIS 12/11 and 29, respectively. Such high accumulation rates imply that local export from the surface layer and sequestration of biogenic silica and organic matter to the sediments may have been much higher than previously suggested.
Resumo:
Este artículo analiza la construcción de agendas locales sobre la privatización de Altos Hornos Zapla (AHZ) por parte de los diarios de referencia dominante de la Provincia de Jujuy. Se aborda el trabajo de interpretación de la coyuntura crítica que va desde la apertura de los sobres de licitación hasta la preadjudicación de Altos Hornos Zapla al único oferente (Aceros Zapla S.A.) para señalar sus especificidades. Sostenemos la hipótesis de que las represen¬taciones que allí circulan ofrecen un panorama de estrategias y contraestrategias vinculadas a la valoración local del proceso de privatización y su articulación con el proyecto neoliberal
Resumo:
An investigation of uranium and thorium contents in extrusive rocks from underwater rises in the Sea of Japan demonstrates that concentrations of these radioactive elements can be used as indicators of geodynamic conditions. It is concluded that basalt volcanism of the Sea of Japan is of continental type.