(Table 1) Magnetozone boundaries at DSDP Site 68-502

Obtaining long, continuous, and undisturbed sections of unconsolidated Neogene deep sea sedimentary sections has been limited by (1) practical length of piston cores to about 30 meters and (2) disturbance of sediment by rotary drilling with Glomar Challenger. The relatively high deposition rates of late Neogene sediments in the North Atlantic and in the Caribbean in particular has limited penetration, with conventional piston coring, to sediments not much older than late Pliocene in the Atlantic and not even through the late Pleistocene in the Caribbean. Rotary drilling has penetrated much older sediments in both areas, but the cores suffered extensive drilling disturbance that seriously degrades the Paleomagnetism of the material. Utilization of the hydraulic piston corer on the Challenger combines the advantage of a generally undisturbed recovery and great penetration to produce long, relatively undisturbed sections of late Neogene and Quaternary sediments suitable for paleomagnetic studies. In this chapter we present paleomagnetic data from Site 502. We tried to determine relative azimuthal orientation of successive cores (see Introduction for details). Because the low latitude of the site meant a small (inclination of about 22°) vertical component of magnetization, reversals of magnetization could easily be detected only in changes in the horizontal component, as 180° shifts in the declination direction of magnetization. Based on information from the core orienting device, a fiducial line was drawn the length of each core prior to cutting it into the standard 1.5 meter sections.

Entrega del título Doctor Honoris causa a Eduardo Galeano

El escritor uruguayo fue distinguido con la máxima distinción que otorga la Universidad Nacional de Cuyo el "Doctorado Honoris Causa". La iniciativa estuvo a cargo de la Facultad de Ciencias Políticas y Sociales y fue aprobada por unanimidad por los integrantes del consejo superior siendo un claro reconocimiento de sus aportes en la construcción de una sociedad más justa y solidaria. La entrega del premio se llevó a cabo en el salón de grado y estuvo a cargo de las máximas autoridades universitarias y de la facultad que promovió la mención.

Algo para alguien, en lugar de otra cosa

"Algo para alguien, en lugar de otra cosa" es una expresión que ayuda a comprender la construcción que hicieron los organismos de Derechos Humanos en nuestro país. Las Madres, los Familiares, los H.I.J.O.S., las Abuelas siempre hicieron algo, para alguien, en lugar de otra cosa: crearon infinidad de formas de lucha, generaron distintos modos de identificación en ese camino y los sostuvieron durante 40 años. Esos símbolos cargados de historia resignificaron la necesidad del juicio y castigo, de la restitución de la identidad de los nietos y nietas y lograron que la sociedad hiciera propia la lucha. Este documental es parte de la historia de esos símbolos y relata, en este caso, lo que nos deja en símbolos, la lucha de los Organismos de Derechos Humanos en defensa de la Memoria, la Verdad y la Justicia.

Magnetostratigraphic age-depth tie points of ODP Leg 208 sites

We report the paleomagnetic and rock magnetic results from discrete sample analysis of sediments from Walvis Ridge, Leg 208 of the Ocean Drilling Program. In an effort to refine the shipboard magnetostratigraphy, alternating field and thermal demagnetization of discrete samples were carried out, predominantly on samples from Sites 1262 and 1267. Results are generally consistent with the shipboard pass-through cryomagnetometer data, though in some cases the discrete samples resolved ambiguities in the reversal record. Significantly, the C24r/C24n reversal boundary was identified at Sites 1262 and 1267, and most boundaries in the Paleocene and Upper Cretaceous sections are now identified to within 10-30 cm. Magnetic mineralogy results show that prior to the late Miocene, the predominant detrital magnetic component was coarse-grained magnetite and that after the late Miocene, titanomagnetite has also been present. This suggests a possible change in detrital source at that time.

Diatom events and Neogene nannofossils of ODP Hole 201-1225A

Shipboard investigation of magnetostratigraphy and shore-based investigation of diatoms and calcareous nannofossils were used to identify datum events in sedimentary successions collected at Ocean Drilling Program (ODP) Leg 201 Site 1225. The goal was to extend the magnetic record previously studied at the same site, ODP Leg 138 Site 851, and provide a comprehensive age model for Site 1225. Two high-magnetic intensity zones at 0-70 and 200-255 meters below seafloor (mbsf) were correlated with lithologic Subunits IA and IC in Hole 1225A. Subunit IA (0-70 mbsf) contains the magnetic reversal record until the Cochiti Subchronozone (3.8 Ma) and has a sedimentation rate of 1.7 cm/k.y. This agrees with previous work done at Site 851. Subunit IC (200-255 mbsf) was not sampled at Site 851. Diatom and nannofossil biostratigraphy constrained this subunit, and we found it to contain the magnetic reversal record between Subchrons C4n.2r and C5n.2n (8.6-9.7 Ma), yielding a sedimentation rate of 2.7 cm/k.y. Biostratigraphy was used to establish the sedimentation rates within Subunits IB and ID (70-200 mbsf and 255-300 mbsf, respectively). These subunits had higher sedimentation rates (~3.4 cm/k.y.) and coincide with the late Miocene-early Pliocene biogenic bloom event (4.5-7 Ma) and the Miocene global cooling trend (10-15 Ma). High biogenic productivity associated with these subunits resulted in the pyritization of the magnetic signal. In lithologic Subunit ID, basement flow is another factor that may be altering the magnetic signal; however, the good correlation between the biostratigraphy and magnetostratigraphy indicates that the magnetic record was locked-in near the seafloor and suggests the age model is robust.

Auxiliary material and basic geochemical and benthic foraminiferal stable isotope data for the interval bracketing Eocene Thermal Maximum 2 (ETM2) at DSDP Sites 401 and 550 in the northeastern Atlantic Ocean

Ever since its discovery, Eocene Thermal Maximum 2 (ETM2; ~53.7 Ma) has been considered as one of the "little brothers" of the Paleocene-Eocene Thermal Maximum (PETM; ~56 Ma) as it displays similar characteristics including abrupt warming, ocean acidification, and biotic shifts. One of the remaining key questions is what effect these lesser climate perturbations had on ocean circulation and ventilation and, ultimately, biotic disruptions. Here we characterize ETM2 sections of the NE Atlantic (Deep Sea Drilling Project Sites 401 and 550) using multispecies benthic foraminiferal stable isotopes, grain size analysis, XRF core scanning, and carbonate content. The magnitude of the carbon isotope excursion (0.85-1.10 per mil) and bottom water warming (2-2.5°C) during ETM2 seems slightly smaller than in South Atlantic records. The comparison of the lateral d13C gradient between the North and South Atlantic reveals that a transient circulation switch took place during ETM2, a similar pattern as observed for the PETM. New grain size and published faunal data support this hypothesis by indicating a reduction in deepwater current velocity. Following ETM2, we record a distinct intensification of bottom water currents influencing Atlantic carbonate accumulation and biotic communities, while a dramatic and persistent clay reduction hints at a weakening of the regional hydrological cycle. Our findings highlight the similarities and differences between the PETM and ETM2. Moreover, the heterogeneity of hyperthermal expression emphasizes the need to specifically characterize each hyperthermal event and its background conditions to minimalize artifacts in global climate and carbonate burial models for the early Paleogene.

Uma cegueira profunda : A ATH em Ésquilo

Entre las definiciones que el concepto de ATH presenta en la tragedia griega clásica, en las obras de Esquilo hay elementos que lo aproximan a la definición dada por E. R. Dodds en The greeks and the irrational, en referencia a la presencia del término en la Ilíada como un "state of mind". Este "estado de ánimo", sin embargo, se perfila como una ceguera profunda del héroe, que sólo entiende las consecuencias de sus acciones después de un intenso sufrimiento. En las siete tragedias conservadas de Esquilo, se puede encontrar el concepto íntimamente vinculado a las muertes heroicas, en el destino de Jerjes en Los persas, o en la maldición de los hermanos Etéocles y Polinices, herederos de las aflicciones de Edipo, en Los siete contra Tebas. Por lo tanto, esta ponencia examina algunos aspectos del concepto en Esquilo y cómo esta "ceguera profunda" es el elemento desencadenante de los acontecimientos trágicos

Chert intervals in DSDP and ODP sites (Table 1)

Radiolarian cherts in the Tethyan realm of Jurassic age were recently interpreted as resulting from high biosiliceous productivity along upwelling zones in subequatorial paleolatitudes the locations of which were confirmed by revised paleomagnetic estimates. However, the widespread occurrence of cherts in the Eocene suggests that cherts may not always be reliable proxies of latitude and upwelling zones. In a new survey of the global spatio-temporal distribution of Cenozoic cherts in Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) sediment cores, we found that cherts occur most frequently in the Paleocene and early Eocene, with a peak in occurrences at ~50 Ma that is coincident with the time of highest bottom water temperatures of the early Eocene climatic optimum (EECO) when the global ocean was presumably characterized by reduced upwelling efficiency and biosiliceous productivity. Cherts occur less commonly during the subsequent Eocene global cooling trend. Primary paleoclimatic factors rather than secondary diagenetic processes seem therefore to control chert formation. This timing of peak Eocene chert occurrence, which is supported by detailed stratigraphic correlations, contradicts currently accepted models that involve an initial loading of large amounts of dissolved silica from enhanced weathering and/or volcanism in a supposedly sluggish ocean of the EECO, followed during the subsequent middle Eocene global cooling by more vigorous oceanic circulation and consequent upwelling that made this silica reservoir available for enhanced biosilicification, with the formation of chert as a result of biosilica transformation during diagenesis. Instead, we suggest that basin-basin fractionation by deep-sea circulation could have raised the concentration of EECO dissolved silica especially in the North Atlantic, where an alternative mode of silica burial involving widespread direct precipitation and/or absorption of silica by clay minerals could have been operative in order to maintain balance between silica input and output during the upwelling-deficient conditions of the EECO. Cherts may therefore not always be proxies of biosiliceous productivity associated with latitudinally focused upwelling zones.

Age models, accumulation rates, sand and carbonates at DSDP Leg 74 holes

Accumulation rates for the five sites drilled during Leg 74 of the Glomar Challenger are presented on a common timescale based on calibration of datum levels to paleomagnetic records in Leg 74 sediments for the Paleogene, and a new compilation by Berggren et al. (1985), for the Neogene, and using the seafloor-spreading magnetic anomaly timescale of Kent (1985). We present data on accumulation of total sediment, of foraminifers, of the noncarbonate portion, and of fish teeth that give a history of productivity, winnowing, carbonate dissolution, and nonbiogenic input to what was then a part of the South Atlantic at about 30 deg S.

La enseñanza en los Institutos Superiores de Formación Docente

La enseñanza en los Institutos Superiores de Formación DocenteEl presente trabajo intenta abordar la problemática de la enseñanza en la carrera de Profesorado de Educación Inicial que se dicta en institutos superiores de formación docente, en Bahía Blanca, provincia de Buenos Aires, Argentina. Para ello, se realiza una breve mención de los aportes de diferentes autores, presentando algunas consideraciones sobre el estado del arte. Se prosigue analizando algunas categorías conceptuales: prácticas de enseñanza, instituciones, docentes, alumnos, formación y conocimiento. Se continúa con la presentación de una posible pedagogía de la formación. Y, a modo de conclusión, se abren algunos interrogantes y se presenta de modo general una propuesta metodológica de investigación pensada para intentar dar respuesta a dichos interrogantes

Realeza y Literatura : Imágenes y tensiones en el cuento de Los Dos Hermanos

El objetivo de este trabajo consiste en explorar las bases de la realeza faraónica, analizando las características y funciones que asume el faraón y los modos establecidos de acceso al trono. Las imágenes proporcionadas por el discurso y las representaciones formalizadas del rey serán puestas en tensión con la experiencia provista por un relato literario: el cuento de Los Dos Hermanos, que constituye un caso interesante para reflexionar sobre las irregularidades y sus formas de legitimación y acomodación en los marcos preestablecidos. La relación entre realeza y literatura será otro de los aspectos a discutir en este trabajo