5,241 research outputs found

    Molecular analysis of urban rabies case from vampire bat in Corrientes, Argentina

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    En abril de 2006 se detectó virus de la rabia (RABV) en un gato doméstico de la ciudad de Corrientes, Argentina. La caracterización molecular identificó al murciélago Desmodus rotundus como la fuente viral. El análisis genético de 22 cepas de RABV aisladas de D. rotundus obtenidos entre 1998–2006 en Argentina, reveló la cocirculación de dos linajes genéticos en la Provincia de Corrientes. La alteración por parte del hombre, del ecosistema del murciélago en la región, podría explicar los cambios en su comportamiento y en la circulación del virus de la rabia

    A Partial Read Barrier for Efficient Support of Live Object-oriented Programming

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    International audienceLive programming, originally introduced by Smalltalk and Lisp, and now gaining popularity in contemporary systems such as Swift, requires on-the-fly support for object schema migration, such that the layout of objects may be changed while the program is at one and the same time being run and developed. In Smalltalk schema migration is supported by two primitives, one that answers a collection of all instances of a class, and one that exchanges the identities of pairs of objects, called the become primitive. Existing instances are collected, copies using the new schema created, state copied from old to new, and the two exchanged with become, effecting the schema migration. Historically the implementation of become has either required an extra level of indirection between an object's address and its body, slowing down slot access, or has required a sweep of all objects, a very slow operation on large heaps. Spur, a new object representation and memory manager for Smalltalk-like languages, has neither of these deficiencies. It uses direct pointers but still provides a fast become operation in large heaps, thanks to forwarding objects that when read conceptually answer another object and a partial read barrier that avoids the cost of explicitly checking for forwarding objects on the vast majority of object accesses

    Ecosystem-bedrock interaction changes nutrient compartmentalization during early oxidative weathering

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    Ecosystem-bedrock interactions power the biogeochemical cycles of Earth's shallow crust, supporting life, stimulating substrate transformation, and spurring evolutionary innovation. While oxidative processes have dominated half of terrestrial history, the relative contribution of the biosphere and its chemical fingerprints on Earth's developing regolith are still poorly constrained. Here, we report results from a two-year incipient weathering experiment. We found that the mass release and compartmentalization of major elements during weathering of granite, rhyolite, schist and basalt was rock-specific and regulated by ecosystem components. A tight interplay between physiological needs of different biota, mineral dissolution rates, and substrate nutrient availability resulted in intricate elemental distribution patterns. Biota accelerated CO2 mineralization over abiotic controls as ecosystem complexity increased, and significantly modified stoichiometry of mobilized elements. Microbial and fungal components inhibited element leaching (23.4% and 7%), while plants increased leaching and biomass retention by 63.4%. All biota left comparable biosignatures in the dissolved weathering products. Nevertheless, the magnitude and allocation of weathered fractions under abiotic and biotic treatments provide quantitative evidence for the role of major biosphere components in the evolution of upper continental crust, presenting critical information for large-scale biogeochemical models and for the search for stable in situ biosignatures beyond Earth.Comment: 41 pages (MS, SI and Data), 16 figures (MS and SI), 6 tables (SI and Data). Journal article manuscrip

    Toxicity results after treatment with Electronic Brachytherapy in patients with endometrial cancer

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    Poster Session [EP-2226] Purpose or Objective To analyse the toxicity outcomes after treatment with Electronic Brachytherapy (XB) in postsurgical endometrial cancer patients treated at our medical centre. Material and Methods Prospective study in which we selected 94 patients, between September/2015 and September/2017, that received treatment with XB administered twice a week after endometrial cancer surgery, with IMRT planificati on. The patients were divided in two groups: Group 1 (57/94) considered high risk received external beam radiotherapy (46Gy) followed by XB (15Gy in 5Gy fractions) and group 2 (37/94) considered intermediate risk received exclusive XB (25Gy in 5Gy fraction s). We analysed the median dose in bladder, rectum and sigmoid D2cc, V50, V35 with XB comparing the doses with Ir192. The vaginal mucosa, gastrointestinal (GI) and genitourinary (GU) toxicities were analysed with the Common Terminology Criteria for Adverse Events (CTCAE 4.0) scale. Results The median dose in bladder with XB vs. Ir192 was: 2cc 62.9 vs. 69.9%, V50 7.1 vs. 12.6Gy, V35 15 vs. 28.1. In rectum XB vs. Ir192 was: D 2cc 64.01% vs. 67.7%, V50 7.8 vs. 10.9Gy, V35 16.5 vs. 31.8Gy. In sigmoid XB vs. Ir 192 was: D 50.37%vs. 58.0%, V50 8.8 vs. 16.2Gy, V35 21.2 vs. 37.5Gy. The median follow- up was 11 months (range 1 - 23, 9 months). In group 1, acute vaginal mucositis (G1) was observed in 35.08% of the patients, GI toxicity (G1) in 5.26% and GU toxicity (G1) in 10.52%. In group 2, we observed acute vaginal mucositis G1 in 45% of the patients and G2 in 10.81%, GI toxicity (G1) occurred in 2.7% and GU toxicity (G1) was present in 16.21%. There was no grade 3 or greater toxicity in any of the groups. Late toxici ty was observed in only 4 patients: Mucositis (G1) in 3 patients and GU toxicity (G1) in 1 patient. Conclusion The dose received by the organs at risk with the XB is less compared to Ir192, with a good coverage of the PTV. The greater toxicity was observe d immediately after the treatment was finished with an important reduction of the symptoms after 6 months. This technique shows excellent results as for toxicity

    High-resolution x-ray study of the nematic - smectic-A and smectic-A - smectic-C transitions in 8barS5-aerosil gels

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    The effects of dispersed aerosil nanoparticles on two of the phase transitions of the thermotropic liquid crystal material 4-n-pentylphenylthiol-4'-n-octyloxybenzoate 8barS5 have been studied using high-resolution x-ray diffraction techniques. The aerosils hydrogen bond together to form a gel which imposes a weak quenched disorder on the liquid crystal. The smectic-A fluctuations are well characterized by a two-component line shape representing thermal and random-field contributions. An elaboration on this line shape is required to describe the fluctuations in the smectic-C phase; specifically the effect of the tilt on the wave-vector dependence of the thermal fluctuations must be explicitly taken into account. Both the magnitude and the temperature dependence of the smectic-C tilt order parameter are observed to be unaffected by the disorder. This may be a consequence of the large bare smectic correlation length in the direction of modulation for this transition. These results show that the understanding developed for the nematic to smectic-A transition for octylcyanobiphenyl (8CB) and octyloxycyanobiphenyl (8OCB) liquid crystals with quenched disorder can be extended to quite different materials and transitions.Comment: 7 pages, 8 figure

    Charge-Carrier Dynamics in 2D Hybrid Metal–Halide Perovskites

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    Hybrid metal–halide perovskites are promising new materials for use in solar cells; however, their chemical stability in the presence of moisture remains a significant drawback. Quasi two-dimensional (2D) perovskites that incorporate hydrophobic organic interlayers offer improved resistance to degradation by moisture, currently still at the cost of overall cell efficiency. To elucidate the factors affecting the optoelectronic properties of these materials, we have investigated the charge transport properties and crystallographic orientation of mixed methylammonium (MA)–phenylethylammonium (PEA) lead iodide thin films as a function of the MA-to-PEA ratio and, thus, the thickness of the “encapsulated” MA lead–halide layers. We find that monomolecular charge-carrier recombination rates first decrease with increasing PEA fraction, most likely as a result of trap passivation, but then increase significantly as excitonic effects begin to dominate for thin confined layers. Bimolecular and Auger recombination rate constants are found to be sensitive to changes in electronic confinement, which alters the density of states for electronic transitions. We demonstrate that effective charge-carrier mobilities remain remarkably high (near 10 cm2V−1s−1) for intermediate PEA content and are enhanced for preferential orientation of the conducting lead iodide layers along the probing electric field. The trade-off between trap reduction, electronic confinement, and layer orientation leads to calculated charge-carrier diffusion lengths reaching a maximum of 2.5 μm for intermediate PEA content (50%)

    The Large Aperture GRB Observatory

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    The Large Aperture GRB Observatory (LAGO) is aiming at the detection of the high energy (around 100 GeV) component of Gamma Ray Bursts, using the single particle technique in arrays of Water Cherenkov Detectors (WCD) in high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). WCD at high altitude offer a unique possibility of detecting low gamma fluxes in the 10 GeV - 1 TeV range. The status of the Observatory and data collected from 2007 to date will be presented.Comment: 4 pages, proceeding of 31st ICRC 200
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