1,490 research outputs found

    Simultaneous analysis of elastic scattering and transfer/breakup channels for the 6He+208Pb reaction at energies near the Coulomb barrier

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    The elastic and alpha-production channels for the 6He+208Pb reaction are investigated at energies around the Coulomb barrier (E_{lab}=14, 16, 18, 22, and 27 MeV). The effect of the two-neutron transfer channels on the elastic scattering has been studied within the Coupled-Reaction-Channels (CRC) method. We find that the explicit inclusion of these channels allows a simultaneous description of the elastic data and the inclusive alpha cross sections at backward angles. Three-body Continuum-Discretized Coupled-Channels (CDCC) calculations are found to reproduce the elastic data, but not the transfer/breakup data. The trivially-equivalent local polarization potential (TELP) derived from the CRC and CDCC calculations are found to explain the features found in previous phenomenological optical model calculations for this system.Comment: 7 pages, 6 figures (replaced with updated version

    Characterization of Vitis vinifera L. subspecies sylvestris (Gmelin) Hegi in the Ebro river Basin (Spain)

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    A wild grapevine population of 76 vines of Vitis vinifera L. subspecies sylvestris (Gmelin) Hegi was found along the Iregua river valley (Northeastern Spain), located in the Ibérica mountain-range. The characterization of this phytogenetic resource was based on an ampelographic description of the male and female individuals and an evaluation of their sanitary state. This shows that the imported North American downy and powdery mildews are the main pathogens, but no symptoms caused by phylloxera on roots were found. Different degrees of infestation caused by Eryophid mites, Colomerus vitis and Calipitrimerus vitis, were also registered on leaves. On the other hand, the red wines obtained show an alcoholic degree situated between 8.5 and 10.8, pH around 3.5 and a high intensity of colour, between 10.2 and, 11.3. The vinegar had only 3.5° of acetic acid. Its phenolic composition is similar to those reported from red and Sherry vinegars produced from cultivars. The genetic analysis based on 18 samples, using 16 nuclear microsatellites, shows a low genetic diversity (He = 0.45). This might be due to inbreeding caused by mating among siblings in this isolated population. The genetic comparison with the allowed cultivars of this Guarantee of Origin showed two distinct gene pools. So it indicated that there is no genetic contribution of these native vines to current instead of actual local varieties. It is necessary to preserve this phytogenetic resource to be used in breeding programs and to restore its destructed habitats by human different impacts.

    The Right to Code and Share Arms

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    Glycerol is, to date, the most widely used cryoprotectant to freeze stallion spermatozoa at concentrations between 2% and 5%. Cryoprotectant toxicity has been claimed to be the single most limiting factor for the success of cryopreservation. In order to evaluate the toxic effects of the concentrations of glycerol used in practice, stallion spermatozoa were incubated in Biggers Whitten and Whittingham (BWW) media supplemented with 0%, 0.5%, 1.5%, 2.5%, 3.5%, and 5% glycerol. In two additional experiments, a hyposmotic (75 mOsm/kg) and a hyperosmotic (900 mOsm/kg) control media were included. Sperm parameters evaluated included cell volume, membrane integrity, lipid peroxidation, caspase 3, 7, and 8 activation, mitochondrial membrane potential, and integrity of the cytoskeleton. Glycerol exerted toxicity at concentrations 3.5% and the maximal toxicity was observed at 5%. The actin cytoskeleton was especially sensitive to glycerol presence, inducing rapid F actin depolymerization at concentrations over 1.5%. The sperm membrane and the mitochondria were other structures affected. The toxicity of glycerol is apparently related to osmotic and nonosmotic effects. In view of our results the concentration of glycerol in the freezing media for stallion spermatozoa should not surpass 2.5%.Funding Agencies|Ministerio de Ciencia e Innovacion-FEDER Madrid, Spain|AGL 2010 20758 (GAN)|Inia|RZ2008-00018-00-00|Junta de Extremadura FEDER GR|10010

    ALMA Observations of Asteroid 3 Juno at 60 Kilometer Resolution

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    We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum images of the asteroid 3 Juno obtained with an angular resolution of 0.042 arcseconds (60 km at 1.97 AU). The data were obtained over a single 4.4 hr interval, which covers 60% of the 7.2 hr rotation period, approximately centered on local transit. A sequence of ten consecutive images reveals continuous changes in the asteroid's profile and apparent shape, in good agreement with the sky projection of the three-dimensional model of the Database of Asteroid Models from Inversion Techniques. We measure a geometric mean diameter of 259pm4 km, in good agreement with past estimates from a variety of techniques and wavelengths. Due to the viewing angle and inclination of the rotational pole, the southern hemisphere dominates all of the images. The median peak brightness temperature is 215pm13 K, while the median over the whole surface is 197pm15 K. With the unprecedented resolution of ALMA, we find that the brightness temperature varies across the surface with higher values correlated to the subsolar point and afternoon areas, and lower values beyond the evening terminator. The dominance of the subsolar point is accentuated in the final four images, suggesting a reduction in the thermal inertia of the regolith at the corresponding longitudes, which are possibly correlated to the location of the putative large impact crater. These results demonstrate ALMA's potential to resolve thermal emission from the surface of main belt asteroids, and to measure accurately their position, geometric shape, rotational period, and soil characteristics.Comment: 8 pages, 3 figures, 2 tables, accepted for publication in the Astrophysical Journal Letter

    ALMA Long Baseline Observations of the Strongly Lensed Submillimeter Galaxy HATLAS J090311.6+003906 at z=3.042

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    We present initial results of very high resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations of the zz=3.042 gravitationally lensed galaxy HATLAS J090311.6+003906 (SDP.81). These observations were carried out using a very extended configuration as part of Science Verification for the 2014 ALMA Long Baseline Campaign, with baselines of up to 15 km. We present continuum imaging at 151, 236 and 290 GHz, at unprecedented angular resolutions as fine as 23 milliarcseconds (mas), corresponding to an un-magnified spatial scale of ~180 pc at z=3.042. The ALMA images clearly show two main gravitational arc components of an Einstein ring, with emission tracing a radius of ~1.5". We also present imaging of CO(10-9), CO(8-7), CO(5-4) and H2O line emission. The CO emission, at an angular resolution of ~170 mas, is found to broadly trace the gravitational arc structures but with differing morphologies between the CO transitions and compared to the dust continuum. Our detection of H2O line emission, using only the shortest baselines, provides the most resolved detection to date of thermal H2O emission in an extragalactic source. The ALMA continuum and spectral line fluxes are consistent with previous Plateau de Bure Interferometer and Submillimeter Array observations despite the impressive increase in angular resolution. Finally, we detect weak unresolved continuum emission from a position that is spatially coincident with the center of the lens, with a spectral index that is consistent with emission from the core of the foreground lensing galaxy.Comment: 9 pages, 5 figures and 3 tables, accepted for publication in the Astrophysical Journal Letter
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