Siliceous fossils in sediments of the Ibero-Moroccan shelf and adjacent deep sea plains

Siliceous skeletons were investigated in two core profiles (9 cores), one off Cap de Sines, Portugal and the other off Cap de Mazagan, Morocco. Total number of skeletons was determined per gram of dried sediment at different core depths of the fraction >21 µ. Results are compared with a core profile from the Arabian Sea. Diatoms are of four groups: (A) marine-planktonic, B) marine-benthic, (C) freshwater and (D) Tertiary species (Trinacria e.g.). Species from groups (B), (C) and (D) are redeposited in all cores taken at a water depth of greater than 100 m. Small numbers of Silicoflagellates and Radiolarians were found throughout the cores from the Ibero-Moroccan shelf. In the Arabian Sea core, Radiolarians were concentrated in distinct horizons in which Tertiary material was redeposited (40-50, 140-150, 250-260 cm). The number of siliceous skeletons per gram of dried sediment decreases more or less rapidly with increasing depth in all cores. Whereas about 2500 skeletons were found in sediments close to the surface, approximately 100 skeletons only were found in deeper (>40 cm) layers. Deeper horizons with more than 100 specimens were interpreted as redeposited material. This sediment contained robust skeletons, resistant against dissolution, as well as benthic and Tertiary material. The decrease of siliceous skeletons relative to core depth depends upon the sedimentation rate. Where the sedimentation rate is high, the opal dissolution zone extends down to 30-60 cm, where the sedimentation rate is low, it is located at 10-30 cm. Below these depths opals disappears. These zones also have approximately the same age (4000 years) everywhere. Siliceous skeletons dissolve differentially, first the Silicoflagellates disappear, second the Diatoms, third the Radiolarians, and fourth the Sponge Spicules. Surface structure of skeletons from near the opal dissolution zones are similar to those of skeletons treated with NaOH. Tertiary diatoms (Trinacria e. g.) and benthic diatoms (Campylodiscus e.g.) dissolve less rapidly than skeletons of modern planktonic diatoms (Coscinodiscus e.g.). The time control of the opal dissolution zones appeared rather independent of various oceanic influences. No evidence was found for effects from upwelling either off Portugal or off Morocco. No difference in dissolution rates was recorded between the abyssal plains lying off these two areas. Likewise, there was no change in solution rates from Pleistocene to Holocene within either one of the abyssal plains. The Mediterranean outflow, which is enriched in dissolved silica, apparently had no effect on dissolution rates of siliceous skeletons in the sediment.

Abundance and biomass of zooplankton from 1981-1985 collected in front of Constanta city, Black Sea

The Est Constanta 1981-1985 dataset contains zooplankton data collected allong a 5 station transect in front of the city Constanta (44°10'N, 28°41.5'E - EC1; 44°10'N, 28°47'E - EC2; 44°10'N, 28°54'E - EC3; 44°10'N, 29°08'E - EC4; 44°10'N, 29°22'E - EC5). Zooplankton sampling was undertaken at 5 stations where samples were collected using a Juday closing net in the 0-10, 10-25, 25-50m layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.

Spectral reflectance library of selected biotic and abiotic coral reef features in Glovers Reef, Belize

Underwater spectral reflectance was measured for selected biotic and abiotic coral reef features of Glovers Reef, Belize from March 6 - 10, 2005. Spectral reflectance's of 63 different benthic types were obtained in-situ. An Ocean Optics USB2000 spectrometer was deployed in an custom made underwater housing with a 0.5 m fiber-optic probe mounted next to an artificial light source. Spectral readings were collected with the probe (bear fibre) about 5 cm from the target to ensure that the target would fill the field of view of the fiber optic (FOV diameter ~4.4 cm), as well as to reduce the attenuating effect of the intermediate water (Roelfsema et al., 2006). Spectral readings included for one target included: 1 reading of the covered spectral fibre to correct for instrument noise, 1 reading of spectralon panel mounted on divers wrist to measure incident ambient light, and 8 readings of the target. Spectral reflectance was calculated for each target by first subtracting the instrument noise reading from each other reading. The corrected target readings were then divided by the corrected spectralon reading resulting in spectral reflectance of each target reading. An average target spectral reflectance was calculated by averaging the eight individual spectral reflectance's of the target. If an individual target spectral reflectance was visual considered an outlier, it was not included in the average spectral reflectance calculation. See Roelfsema at al. (2006) for additional info on the methodology of underwater spectra collection.

Entre la universidad, la empresa y el estado : Trayectorias personales, saberes y prácticas en la génesis del diseño industrial y de la comunicación visual en la Argentina. Décadas 1950 y 1960

El trabajo se propone analizar diferentes relaciones entre la universidad, la empresa privada y el Estado al momento del surgimiento del diseño industrial y de la comunicación visual, inscriptas bajo el ala del diseño como disciplina institucionalizada. Para tal fin haremos hincapié en las trayectorias de individuos y grupos que promovieron los nuevos espacios como cátedras, carreras, institutos, y departamentos en las universidades, departamentos y agencias en las empresas, e impulsaron la investigación y la formación especializada en una agencia estatal. A este respecto nos planteamos la reconstrucción y análisis de las posiciones y los tramas de relaciones sociales entre los actores, los liderazgos e ideas que confluyeron en ese marco institucionalizador. A fines de la década del ´50 se abrieron espacios en instituciones estatales ?universidades nacionales y agencias del Estado- desde los que se promovió la formación e investigación en diseño industrial y comunicación visual. Al mismo tiempo, en medio del proceso de industrialización que demandaba nuevos especialistas, las empresas privadas abrieron secciones específicas dedicadas a proyectar diseños integrales para sus productos. Para entender los sistemas de valores sobre los que se originaron estos espacios indagaremos en los documentos, artículos, libros y bienes materiales ?entre otros- que los propios actores pusieron en circulación en ese tiempo y lugar. Haremos foco en las categorías de análisis y en las definiciones por ellos dictadas en ese momento sobre el diseño. El impulso a esta nueva disciplina se abordará desde la complejidad de las trayectorias de estos agentes entendiendo la pluralidad de intereses, afinidades y razones dadas en los ámbitos público y privado. Desde esta perspectiva intentaremos dar cuenta de las historias de los individuos involucrados y de los grupos que integraron esos espacios, y su injerencia en la creación de una agencia estatal. Así podremos constatar los factores que determinaron las políticas de cambio, las prácticas y los métodos de estudio propuestos en la universidad, la empresa privada y el Estado

Servicios bibliotecarios accesibles para personas con discapacidad visual en la Universidad Nacional de La Plata, Argentina

El trabajo, de tipo descriptivo exploratorio, pretende conocer cuál es el estado en que se encuentran algunas de las bibliotecas universitarias de la UNLP para ofrecer un servicio accesible a personas con discapacidad visual. Se analiza qué servicios de este tipo poseen actualmente, con qué barreras se enfrentan los usuarios y qué soluciones se han implementado. A tal fin se indagará, por un lado, cómo están diseñados los sitios web de las bibliotecas elegidas, y por otro, cómo integran estas bibliotecas en sus servicios y productos documentales a estas personas, esto es, si cuentan con material bibliográfico y servicios accesibles. Por último, se esbozan algunas propuestas para superar la situación actual en estas bibliotecas universitarias