36 research outputs found

    Habitat associations of post-breeding female southern elephant seals (Mirounga leonina) from Península Valdés, Argentina

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    Research on marine mammal habitat-associations often uses satellite remote sensing of sea surface temperature, chlorophyll concentration, and sea surface height to map mesoscale features, which may indicate areas of enhanced productivity and prey availability. However, for species that feed at depths >400 m, the increased productivity associated with mesoscale features observed near the surface may have little or no immediate effect on habitat-associations at depth. As a result, previous studies have found a weak correlation between mesoscale features and the movements of marine mammals. The advantage of biologging is that hydrographic variables are recorded in situ and at foraging depths using animal-borne instruments with sensors for temperature, conductivity (salinity), and dissolved oxygen. The goal of this study was to characterize the habitat-associations of female southern elephant seals (SES) from Península Valdés, Argentina during the post-breeding foraging trip. Although female SES exhibited significant habitat-associations with sea surface height anomaly and chlorophyll concentrations, the presence or absence of eddies was not predictive of foraging behavior, and the majority of foraging dives (74%) and prey encounters (77%) occurred in the absence of eddies. The strongest habitat-association was with deep (>500 m) and cold (3.73 ± 1.29 °C) subantarctic water, primarily during foraging dives from dusk to dawn. Female SES made most of their foraging dives (68%, mean maximum depth of 539 ± 226 m) and had the most prey encounters (67%) in Antarctic Intermediate Water (AAIW), which is formed near the Subantarctic Front on the northern flank of the Antarctic Circumpolar Current. Our results suggest that AAIW is the principal foraging habitat of female SES from Península Valdés, which may not be directly associated with near-surface mesoscale features. Future research on the habitat-associations for SES and other deep-diving marine mammals should focus on indices of foraging success and the hydrographic features of water masses at foraging depths, not mesoscale features observed near the surface.Fil: McGovern, K.A.. Texas A&M University; Estados UnidosFil: Rodriguez, Diego Horacio. Universidad Nacional de Mar del Plata, Facultad de Ciencias Exactas y Naturales, Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Lewis, Mirtha Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Eder, Elena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Piola, Alberto Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; ArgentinaFil: Davis, R.W.. Texas A&M University; Estados Unido

    Electronic Structure of Calcium Hexaboride within the Weighted Density Approximation

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    We report calculations of the electronic structure of CaB6_6 using the weighted density approximation (WDA) to density functional theory. We find a semiconducting band structure with a sizable gap, in contrast to local density approximation (LDA) results, but in accord with recent experimental data. In particular, we find an XX-point band gap of 0.8 eV. The WDA correction of the LDA error in describing the electronic structure of CaB6_6 is discussed in terms of the orbital character of the bands and the better cancelation of self-interactions within the WDA.Comment: 1 figur

    AMMI analysis of the adaptability and yield stability of yellow passion fruit varieties

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    High yield stability and adaptability of yellow passion fruit varieties (Passiflora edulis Sims. f. flavicarpa Deg.) are highly desirable attributes when exploring different environments. This study aimed to evaluate the adaptability and yield stability of yellow passion fruit varieties using AMMI (additive main effects and multiplicative interaction) and other ancillary statistics. Twelve varieties were evaluated in eight environments. Analysis of variance showed effects attributable to the varieties (G), environment (E) and their interaction (G × E). The first two multiplicative components of the interaction accounted for 69% of the sum of squares. The scores of the principal interaction components showed high variability for the environments relative to the variety effects. High varietal phenotypic stability was observed in three environments; which can be used in yellow passion fruit breeding programs for initial selection trials. A biplot-AMMI analysis and yield stability index incorporating the AMMI stability value and yield capacity in a single non-parametric index were useful for discriminating genotypes with superior and stable fruit yield. AMMI analysis also allowed for the identification of more productive varieties in specific environments, leading to significant increase in passion fruit productivity

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Modeling NIF experimental designs with adaptive mesh refinement and Lagrangian hydrodynamics

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    Incorporation of adaptive mesh refinement (AMR) into Lagrangian hydrodynamics algorithms allows for the creation of a highly powerful simulation tool effective for complex target designs with three-dimensional structure. We are developing an advanced modeling tool that includes AMR and traditional arbitrary Lagrangian-Eulerian (ALE) techniques. Our goal is the accurate prediction of vaporization, disintegration and fragmentation in National Ignition Facility (NIF) experimental target elements. Although our focus is on minimizing the generation of shrapnel in target designs and protecting the optics, the general techniques are applicable to modern advanced targets that include three-dimensional effects such as those associated with capsule fill tubes. Several essential computations in ordinary radiation hydrodynamics need to be redesigned in order to allow for AMR to work well with ALE, including algorithms associated with radiation transport. Additionally, for our goal of predicting fragmentation, we include elastic/plastic flow into our computations. We discuss the integration of these effects into a new ALE-AMR simulation code. Applications of this newly developed modeling tool as well as traditional ALE simulations in two and three dimensions are applied to NIF early-light target designs

    Optimization of experimental designs by incorporating NIF facility impacts

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    For experimental campaigns on the National Ignition Facility (NIF) to be successful, they must obtain useful data without causing unacceptable impact on the facility. Of particular concern is excessive damage to optics and diagnostic components. There are 192 fused silica main debris shields (MDS) exposed to the potentially hostile target chamber environment on each shot. Damage in these optics results either from the interaction of laser light with contamination and pre-existing imperfections on the optic surface or from the impact of shrapnel fragments. Mitigation of this second damage source is possible by identifying shrapnel sources and shielding optics from them. It was recently demonstrated that the addition of 1.1-mm thick borosilicate disposable debris shields (DDS) blocks the majority of debris and shrapnel fragments from reaching the relatively expensive MDS's. However, DDS's cannot stop large, fast moving fragments. We have experimentally demonstrated one shrapnel mitigation technique showing that it is possible to direct fast moving fragments by changing the source orientation, in this case a Ta pinhole array. Another mitigation method is to change the source material to one that produces smaller fragments. Simulations and validating experiments are necessary to determine which fragments can penetrate or break 1-3 mm thick DDS's. Three-dimensional modeling of complex target-diagnostic configurations is necessary to predict the size, velocity, and spatial distribution of shrapnel fragments. The tools we are developing will be used to assure that all NIF experimental campaigns meet the requirements on allowed level of debris and shrapnel generation
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