Presentación de "Deja que entre la luz del sol: archivos de gobierno e inseguridades nacionales", de Barbara Weinstein

Fil: Lenci, María Laura. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

De tráfico de ideas y redes científicas internacionales : Reseña de: Chicote, Gloria B., Göbel, Barbara (eds.) (2011), Ideas viajeras y sus objetos: El intercambio científico entre Alemania y América austral, Madrid, Iberoamericana-Vervuert, 356 págs

Fil: Labra, Diego. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Presentación de "Deja que entre la luz del sol: archivos de gobierno e inseguridades nacionales", de Barbara Weinstein

Fil: Lenci, María Laura. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

De tráfico de ideas y redes científicas internacionales : Reseña de: Chicote, Gloria B., Göbel, Barbara (eds.) (2011), Ideas viajeras y sus objetos: El intercambio científico entre Alemania y América austral, Madrid, Iberoamericana-Vervuert, 356 págs

Fil: Labra, Diego. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Benthic foraminiferal assemblage changes during interstadial 4 to 8 in ODP Site 146-893A, Santa Barbara Basin

Benthic foraminiferal assemblages from Santa Barbara Basin exhibit major faunal and ecological switches associated with late Quaternary millennial- to decadal-scale global climate oscillations. Repeated turnovers of entire faunas occurred rapidly (<40-400 yr) without extinction or speciation in conjunction with Dansgaard-Oeschger shifts in thermohaline circulation, ventilation, and climate, confirming evolutionary model predictions of Roy et al. Consistent faunal successions of dysoxic taxa during successive interstadials reflect the extreme sensitivity and adaptation of the benthic ecosystem to the rapid environmental changes that marked the late Quaternary and possibly other transitional intervals in the history of the Earth's ocean-atmosphere-cryosphere system. These data support the hypothesis that broad segments of the biosphere are well adapted to rapid climate change.

Coccolith fluxes in the Santa Barbara Basin

We investigate the long-term stability of El Niño-Southern Oscillation and Pacific Decadal Oscillation based on the examination of coccolithophore assemblages in a largely laminated 35 ka sedimentary record, retrieved in the Santa Barbara Basin (core MD02-2503). At a centennial scale coccolith assemblages indicate low primary production in the basin from 35 to 11.5 ka B.P., whereas the Holocene is characterized by high-productivity conditions. This pattern demonstrates the influence of the glacial-interglacial cycles on productivity and, by inference, on the nutrient supply by the upwelling cell off Point of Conception. On a shorter scale, laminations associated with Dansgaard-Oeschger events appear to be due to an injection of poorly oxygenated waters in the deepest part of the basin rather than anoxia due to high primary production. A seasonal sampling in seven laminated sections (spanning from 20 to 220 years) extracted from Holocene, Bølling-Allerød, and Dansgaard-Oeschger event 3 indicates El Niño probably existed continuously during the last 28 ka. The frequency of El Niño varied through time (between 1/2.5 and 1/5 event/a) and appearing to follow the precession cycle. El Niño exhibits higher (lower) frequencies when the precession values are lower (higher). Finally, the Holocene is characterized by a decrease in El Niño's frequencies due to the reinforcement of El Niño through this period.