Geochemical composition and granulometry of ODP Hole 167-1017E sediments

Intensification of North Pacific Intermediate Water during the Younger Dryas and stadials of the last glacial episode has been advocated by Kennett and his colleagues based on studies of ventilation history in Santa Barbara Basin. Because Santa Barbara Basin is a semi-isolated marginal basin, this hypothesis requires testing in sequences on the upper continental margin facing the open-ocean of the Pacific. Ocean Drilling Program Site 1017 is located on the upper slope of southern California off Point Conception close to the entrance of Santa Barbara Basin, an ideal location to test the hypothesis of late Quaternary switching in intermediate waters. We examined chemical and mineral composition, sedimentary structures, and grain size of hemipelagic sediments representing the last 80 k.y. at this site to detect changes in behavior of intermediate waters. We describe distinct compositional and textual variations that appear to reflect changes in grain size in response to flow velocity fluctuations of bottom waters. Qualitative estimates of changes in degree of pyritization indicate better ventilation of bottom water during intervals of stronger bottom-water flow. Comparison between variations in the sediment parameters and the planktonic d18O record indicates intensified bottom-current activity during the Younger Dryas and stadials of marine isotope Stage 3. This result strongly supports the hypothesis of Kennett and his colleagues. Our investigation also suggests strong grain-size control on organic carbon content (and to less extent carbonate carbon content). This, in turn, suggests the possibility that organic carbon content of sediments, which is commonly used as an indicator of surface productivity, can be influenced by bottom currents.

Nannofossil datums and abundance in sediments from ODP Leg 164 sites

Twenty routinely used nannofossil datums in the late Neogene and Quaternary were identified at three Blake Ridge sites drilled during Leg 164. The quantitative investigation of the nannofossil assemblages in 236 samples selected from Hole 994C provide new biostratigraphic and paleoceanographic information. Although mostly overlooked previously, Umbilicosphaera aequiscutum is an abundant component of the late Neogene flora, and its last occurrence at ~2.3 Ma is a useful new biostratigraphic event. Small Gephyrocapsa evolved within the upper part of Subzone CN11a (~4.3 Ma), and after an initial acme, it temporarily disappeared for 400 k.y., between 2.9 and 2.5 Ma. Medium-sized Gephyrocapsa evolved in the latest Pliocene ~2.2 Ma), and after two short temporary disappearances, common specimens occurred continuously just above the Pliocene/Pleistocene boundary. The base of Subzone CN13b should be recognized as the beginning of the continuous occurrence of medium-sized (>4 µm) Gephyrocapsa. Stratigraphic variation in abundance of the very small placoliths and Florisphaera profunda alternated, indicating potential of the former as a proxy for the paleoproductivity. At this site, it is likely that upwelling took place during three time periods in the late Neogene (6.0-4.6 Ma, 2.3-2.1 Ma, and 2.0-1.8 Ma) and also in the early Pleistocene (1.4-0.9 Ma). Weak upwelling is also likely to have occurred intermittently through the late Pliocene. Due to the sharp and abrupt turnover of the nannofossils, which resulted from an evolution of very competitive species, the paleoproductivity of the late Pleistocene is not clear. The site was mostly in an oligotrophic central gyre setting during the 4.6- to 2.3-Ma interval, intermittently between 2.1 and 1.4 Ma, and continuously for the last several tens of thousand years.

Las cárceles en el Rosario de la 2da mitad de siglo XIX : Fuentes y enfoques

Este artículo revisa modos de abordaje de las cárceles a partir de los archivos rosarinos. Mediante un recorrido por los diversos fondos documentales se formulan interrogantes que van desde las responsabilidades judiciales, policiales y ejecutivas frente al movimiento diario de la cárcel hasta la materialidad misma de sus condiciones edilicias y de su aprovisionamiento, con el objetivo de presentar cierta dinámica de funcionamiento. La exploración de fuentes judiciales permite reconstruir dichas condiciones desde las voces de quienes habitaban estos sitios. Se revisa, además, la problemática relación entre las autoridades que comprendían las jurisdicciones de los detenidos reunidos físicamente en un mismo lugar, que además era el cuartel de gendarmes

Vocational guidance in people with special educational needs as the result of visual impairment during the transition stage from high school to advanced education

This work proposes to seek for the factors related to the choices that people with special educational needs make as the result of the visual impairment, during the transition stage from high school to advanced education. Therefore, we have taken into consideration that Vocational Guidance and the transition towards adulthood get specific characteristics in case of visually impaired young people, particularly in what's related to continue with advanced education. The focus of this work is to be able to clarify the existence of factors that make this transition stage easier or harder, through the observation of visually impaired and blind people who complete high school. This matter has aroused interest and concern about the strategies to follow to ensure the successful entrance and remaining in the selected advanced education. However, if we don?t know the factors involved in the described fact, it's difficult to design an appropriate intervention strategy. Then, in order to take acknowledge about the specific issues of visually impaired young people who complete high school, we chose a special school for this disability and some students who will join this project

Otras voces, otros cánones

El presente artículo pretende traer a la discusión la situación nunca explicada dentro de los debates sobre el canon en cuanto al papel que ocupan las escritoras dentro de una selección determinada. En el ámbito rioplatense, las escritoras carecen de importancia para el canon más generalizado (expresado en los programas de estudio universitarios más corrientes), en tanto su literatura no viene a describir los grandes temas nacionales. La historia de la literatura argentina, por ejemplo, se ha jugado así exclusivamente en la preponderancia de los nombres masculinos, ¿pero podría pensarse una historia de la literatura rioplatense en la que las escritoras tuvieran una presencia equivalente a la de sus pares varones? La obras de Griselda Gambaro y Marosa di Giorgio, cuya singularidad permitiría brindarles un pasaporte de entrada por derecho propio, son tomadas como ejemplos para considerar esa pregunta.

Indígenas, tierra y política en Colombia : Las comunidades indígenas del Bolívar Grande en la segunda mitad del siglo XIX

Este artículo analiza la población indígena del Bolívar Grande (Colombia) en el tercer cuarto del siglo XIX, en el contexto de formación de la nación y la expansión de la ganadería. Mostramos cómo los elementos discursivos sobre la nación mestiza y la identidad política ciudadana, más el fraccionamiento interno de las comunidades indígenas, facilitaron las acciones de ganaderos y poblaciones mestizas para intentar disolver la propiedad comunal de las tierras de los resguardos. También analizamos las formas de resistencia desplegadas por los indígenas, en especial la instrumentalización que realizaron del discurso liberal, y las negociaciones que establecieron con otros sectores sociales y políticos para defender sus intereses