14,368 research outputs found

    Seafloor Characterization from Spatial Variation of Multibeam Backscatter vs. Best Estimated Grazing Angle

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    Backscatter vs. grazing angle, which can be extracted from multibeam backscatter data, depends on characteristics of the multibeam system and the angular responses of backscatter that are characteristic of different seafloor properties, such as sediment hardness and roughness. Changes in backscatter vs. grazing angle that are contributed by the multibeam system normally remain fixed over both space and time. Therefore, they can readily be determined and removed from backscatter data. The component of backscatter vs. grazing angle due to the properties of sediments varies from location to location, as the sediment changes. The sediment component of variability can be inferred using the redundant observations from different grazing angles in several small sections of seafloor assuming that the sediment property is uniform in any given section of seafloor yet varies from one section of the seafloor to another. The multibeam data used in this research is from the ONR sponsored STRATAFORM project. The location of the study area was the mid-outer continental shelf off New Jersey. A small subset (11 x 17 km) of the NJ multibeam survey was selected and divided into 1380 equal working cells. The backscatter vs. grazing angle dependence for each cell was computed by averaging backscatter data by the corresponding grazing angles using all data with the same grazing angle from different survey lines. Taking into account the effects of local topographic variations of the seabed, the estimated grazing angle for each beam has been computed from available adjacent soundings within a 15-meter radius using a least squares fit with a Butterfly weighting function. A graphic interface was developed to ease evaluation of the spatial variation of backscatter vs. grazing angle. With a mouse click, images based on different subsets of the data can be compared throughout the survey area. The subsets were created from specific grazing angles. These images show significant variations between nadir and off-nadir beams. Variations apparent in the images may provide some indication of the sediment (or seafloor) characteristics, which can be compared to ground truth data (sediment grain size) and measured values such as velocity and density

    Estimating oil concentration and flow rate with calibrated vessel-mounted acoustic echo sounders

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    As part of a larger program aimed at evaluating acoustic techniques for mapping the distribution of subsurface oil and gas associated with the Deepwater Horizon-Macondo oil spill, observations were made on June 24 and 25, 2010 using vessel-mounted calibrated single-beam echo sounders on the National Oceanic and Atmospheric Administration ship Thomas Jefferson. Coincident with visual observations of oil at the sea surface, the 200-kHz echo sounder showed anomalously high-volume scattering strength in the upper 200 m on the western side of the wellhead, more than 100 times higher than the surrounding waters at 1,800-m distance from the wellhead, and weakening with increasing distance out to 5,000 m. Similar high-volume scattering anomalies were not observed at 12 or 38 kHz, although observations of anomalously low-volume scattering strength were made in the deep scattering layer at these frequencies at approximately the same locations. Together with observations of ocean currents, the acoustic observations are consistent with a rising plume of small (\u3c 1-mm radius) oil droplets. Using simplistic but reasonable assumptions about the properties of the oil droplets, an estimate of the flow rate was made that is remarkably consistent with those made at the wellhead by other means. The uncertainty in this acoustically derived estimate is high due to lack of knowledge of the size distribution and rise speed of the oil droplets. If properly constrained, these types of acoustic measurements can be used to rapidly estimate the flow rate of oil reaching the surface over large temporal and spatial scales

    Mirabolano 29C: obtenção de portaenxertos clonais por mergulhia aérea.

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    WIPI1 promotes fission of endosomal transport carriers and formation of autophagosomes through distinct mechanisms.

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    Autophagosome formation requires PROPPIN/WIPI proteins and monophosphorylated phosphoinositides, such as phosphatidylinositol-3-phosphate (PtdIns3P) or PtdIns5P. This process occurs in association with mammalian endosomes, where the PROPPIN WIPI1 has additional, undefined roles in vesicular traffic. To explore whether these functions are interconnected, we dissected routes and subreactions of endosomal trafficking requiring WIPI1. WIPI1 specifically acts in the formation and fission of tubulo-vesicular endosomal transport carriers. This activity supports the PtdIns(3,5)P <sub>2</sub> -dependent transport of endosomal cargo toward the plasma membrane, Golgi, and lysosomes, suggesting a general role of WIPI1 in endosomal protein exit. Three features differentiate the endosomal and macroautophagic/autophagic activities of WIPI1: phosphoinositide binding site II, the requirement for PtdIns(3,5)P <sub>2</sub> , and bilayer deformation through a conserved amphipathic α-helix. Their inactivation preserves autophagy but leads to a strong enlargement of endosomes, which accumulate micrometer-long endosomal membrane tubules carrying cargo proteins. WIPI1 thus supports autophagy and protein exit from endosomes by different modes of action. We propose that the type of phosphoinositides occupying its two lipid binding sites, the most unusual feature of PROPPIN/WIPI family proteins, switches between these effector functions.Abbreviations: EGF: epidermal growth factorEGFR: epidermal growth factor receptorKD: knockdownKO: knockoutPtdIns3P: phosphatidylinositol-3-phosphatePtdIns5P: phosphatidylinositol-5-phosphatePtdIns(3,5)P <sub>2</sub> : phosphatidylinositol-3,5-bisphosphateTF: transferrinTFRC: transferrin receptorWT: wildtype

    Lithostratigraphy, biostratigraphy, and stable-isotope stratigraphy of cores from ODP Leg 105 site surveys, Labrador Sea and Baffin Bay

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    Trigger weight (TWC) and piston (PC) cores obtained from surveys of the three sites drilled during Ocean Drilling Program (ODP) Leg 105 were studied in detail for benthic foraminiferal assemblages, total carbonate (all sites), planktonic foraminiferal abundances (Sites 645 and 647), and stable isotopes (Sites 646 and 647). These high-resolution data provide the link between modern environmental conditions represented by the sediment in the TWC and the uppermost cores of the ODP holes. This link provides essential control data for interpretating late Pleistocene paleoceanographic records from these core holes. At Site 645 in Baffin Bay, local correlation is difficult because the area is dominated by ice-rafted deposits and by debris flows and/or turbidite sedimentation. At the two Labrador Sea sites (646 and 647), the survey cores and uppermost ODP cores can be correlated. High-resolution data from the site survey cores also provide biostratigraphic data that refine the interpretations compiled from core-catcher samples at each ODP site

    A versão Portuguesa do European Deprivation Index: Um Instrumento para o Estudo das Desigualdades em Saúde

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    Introduction: Tackling socioeconomic health inequalities is a big public health challenge and ecological deprivation indexes are essential instruments to monitor and understand them. In Portugal, no standard ecological deprivation index exists, contrasting with other countries. We aimed to describe the construction of the Portuguese version of a transnational deprivation index, European Deprivation Index. Material and Methods: The European Deprivation Index was developed under the Townsend theorization of deprivation. Using data from the European Union - Statistics on Income and Living Conditions Survey, we obtained an indicator of individual deprivation. This indicator became the gold-standard variable, based on what we selected the variables at aggregate level (census) to be included in the European Deprivation Index, a total of eight. The European Deprivation Index was produced for the smallest area unit possible (n = 16 094, mean/area = 643 inhabitants) and resulted from the weighted sum of the previous variables. It was then classified into quintiles. Results: The first quintile (least deprived) comprised 20.9% national population and the fifth quintile (most deprived) 18.0%. The European Deprivation Index showed a clear geographic pattern – most deprived areas concentrated in the South and in the inner North and Centre of the country, and the least deprived areas in the coastal areas of North and Centre and in the Algarve. Discussion: The development of the European Deprivation Index was grounded on a solid theoretical framework, individual and aggregate variables, and on a longitudinal Europe-wide survey allowing its replication over the time and in any European country. Conclusion: Hopefully, the European Deprivation Index will start being employed by those interested in better understand health inequalities not only in Portugal but across Europe.This work was supported by Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia in the framework of project UID/BIM/04293/2013. AIR and MFP would also like to thank to FCT – Fundação para a Ciência e a Tecnologia for the grants PTDC/SAU-EPI/113424/2009 and SFRH/BD/82529/2011

    A Population of Teraelectronvolt Pulsar Wind Nebulae in the H.E.S.S. Galactic Plane Survey

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    The most numerous source class that emerged from the H.E.S.S. Galactic Plane Survey are Pulsar Wind Nebulae (PWNe). The 2013 reanalysis of this survey, undertaken after almost 10 years of observations, provides us with the most sensitive and most complete census of gamma-ray PWNe to date. In addition to a uniform analysis of spectral and morphological parameters, for the first time also flux upper limits for energetic young pulsars were extracted from the data. We present a discussion of the correlation between energetic pulsars and TeV objects, and their respective properties. We will put the results in context with the current theoretical understanding of PWNe and evaluate the plausibility of previously non-established PWN candidates.Comment: 4 pages, 5 figures. In Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), Rio de Janeiro (Brazil

    Configuration mixing calculation for complete low-lying spectra with the mean-field Hamiltonian

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    We propose a new theoretical approach to ground and low-energy excited states of nuclei extending the nuclear mean-field theory. It consists of three steps: stochastic preparation of many Slater determinants, the parity and angular momentum projection, and diagonalization of the generalized eigenvalue problems. The Slater determinants are constructed in the three-dimensional Cartesian coordinate representation capable of describing arbitrary shape of nuclei. We examine feasibility and usefulness of the method by applying the method with the BKN interaction to light 4N-nuclei, 12C, 16O, and 20Ne. We discuss difficulties of keeping linear independence for basis states projected on good parity and angular momentum and present a possible prescription.Comment: 12 pages, revtex

    Escape configuration lattice near the nematic-isotropic transition: Tilt analogue of blue phases

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    We predict the possible existence of a new phase of liquid crystals near the nematic-isotropic (NI NI ) transition. This phase is an achiral, tilt-analogue of the blue phase and is composed of a lattice of {\em double-tilt}, escape-configuration cylinders. We discuss the structure and the stability of this phase and provide an estimate of the lattice parameter.Comment: 5 pages, 6 figures (major revision, typos corrected, references added
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