2,411 research outputs found

    Earth matter density uncertainty in atmospheric neutrino oscillations

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    That muon neutrinos νμ\nu_{\mu} oscillating into the mixture of tau neutrinos ντ\nu_{\tau} and sterile neutrinos νs\nu_{s} has been studied to explain the atmospheric νμ\nu_{\mu} disappearance. In this scenario, the effect of Earth matter is a key to determine the fraction of νs\nu_{s}. Considering that the Earth matter density has uncertainty and this uncertainty has significant effects in some neutrino oscillation cases, such as the CP violation in very long baseline neutrino oscillations and the day-night asymmetry for solar neutrinos, we study the effects caused by this uncertainty in the above atmospheric νμ\nu_{\mu} oscillation scenario. We find that this uncertainty seems to have no significant effects and that the previous fitting results need not to be modified fortunately.Comment: 7 pages, 1 figure, to appear in Phys. Rev.

    Multilocus sequence types of invasive Corynebacterium diphtheriae isolated in the Rio de Janeiro urban area, Brazil

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    Invasive infections caused by Corynebacterium diphtheriae in vaccinated and non-vaccinated individuals have been reported increasingly. In this study we used multilocus sequence typing (MLST) to study genetic relationships between six invasive strains of this bacterium isolated solely in the urban area of Rio de Janeiro, Brazil, during a 10-year period. Of note, all the strains rendered negative results in PCR reactions for the tox gene, and four strains presented an atypical sucrose-fermenting ability. Five strains represented new sequence types. MLST results did not support the hypothesis that invasive (sucrose-positive) strains of C. diphtheriae are part of a single clonal complex. Instead, one of the main findings of the study was that such strains can be normally found in clonal complexes with strains related to non-invasive disease. Comparative analyses with C. diphtheriae isolated in different countries provided further information on the geographical circulation of some sequence types

    Enabling the classroom and the curriculum: higher education, literary studies and disability

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    In this article the tripartite model of disability is applied to the lived experience of twenty-first-century higher education. The tripartite model facilitates a complex understanding of disability that recognises assumptions and discrimination but not at the cost of valued identity. This being so, not only the normative positivisms and non-normative negativisms but also the non-normative positivisms of the classroom and the curriculum are explored. Inclusion is taken as the starting point and the argument progresses to a profound and innovational appreciation of disability. The problem addressed is that inclusion, as shown in The Biopolitics of Disability, constitutes little more than inclusion-ism until disability is recognised in the context of alternative lives and values that neither enforce nor reify normalcy. Informed by this understanding, the article adopts the disciplinary example of literary studies and refers to Brian Friel’s Molly Sweeney as a primary text. The conclusion is that, despite passive and active resistance, disability enters higher education in many ways, most of which are beneficial to students and educators alike

    Ceramic/metal nanocomposites by lyophilization: Processing and HRTEM study

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    5 páginas, 8 figuras, 1 tabla.-- El pdf del artículo es el manuscrito de autor.This work describes a wet-processing route based on spray-freezing and subsequent lyophilization designed to obtain nanostructured ceramic/metal powders. Starting from the ceramic powder and the corresponding metal salt, a water-based suspension is sprayed on liquid nitrogen. The frozen powders are subsequently freeze-dried, calcined and reduced. The material was analyzed using X-ray diffraction analysis at all stages. High resolution transmission electron microscopy studies showed a uniform distribution of metal nanoparticles on the ceramic grain surfaces, good interfaces and high crystallinity, with an average metal particle size in the nanometric range.This work was supported by the Spanish Ministry of Science and Innovation (MICINN) under the project MAT2009-14542-C02 and the Government of the Principality of Asturias through PCTI and ERDF (European Regional Development Fund) 2007-2013 under project PC10-65. C.F. Gutierrez- Gonzalez acknowledges CSIC and ESF for the concession of a JAE-Doc 2009 grant. S. Agouram thanks the Spanish Ministry of Science and European Social Fund for financial support.Peer reviewe

    CIRCULAR DICHROISM OF LIGHT-HARVESTING COMPLEXES FROM PURPLE PHOTOSYNTHETIC BACTERIA

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    The CD spectra of a range of antenna complexes from several different species of purple photosynthetic bacteria were recorded in the wavelength range of 190 to 930 nm. Analysis of the far UV CD (190 to 250 nm) showed that in each case except for the B800-850 from Chr. vinosum the secondary structure of the light-harvesting complexes contains a large amount of α-helix (50%) and very little 0-pleated sheet. This confirms the predictions of the group of Zuber of a high a-helical content based upon consideration of the primary structures of several antenna apoproteins. The CD spectra from the carotenoids and the bacteriochlorophylls show considerable variations depending upon the type of antenna complex. The different amplitude ratios in the CD spectrum for the bacteriochlorophyll Qy, Qx and Soret bands indicate not only different degrees of exciton coupling, but also a strong and variable hyperchromism (Scherz and Parson, 1984a, b)

    The Uplift Capacity of Anchors Embedded in Loose Sand

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    The results of scale model tests of uplift capacity of shallow and deep anchors in loose fully saturated sands are presented. The anchors were subjected to static, cyclic and post cyclic loading. The parameters tested included the effects of embedment ratio, anchor shape, relative soil density, amplitude and number of cycles, and post cyclic response to loading. The factors influencing the behavior of the anchors are discussed

    MOA-2009-BLG-387Lb: A massive planet orbiting an M dwarf

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    We report the discovery of a planet with a high planet-to-star mass ratio in the microlensing event MOA-2009-BLG-387, which exhibited pronounced deviations over a 12-day interval, one of the longest for any planetary event. The host is an M dwarf, with a mass in the range 0.07 M_sun < M_host < 0.49M_sun at 90% confidence. The planet-star mass ratio q = 0.0132 +- 0.003 has been measured extremely well, so at the best-estimated host mass, the planet mass is m_p = 2.6 Jupiter masses for the median host mass, M = 0.19 M_sun. The host mass is determined from two "higher order" microlensing parameters. One of these, the angular Einstein radius \theta_E = 0.31 +- 0.03 mas, is very well measured, but the other (the microlens parallax \pi_E, which is due to the Earth's orbital motion) is highly degenate with the orbital motion of the planet. We statistically resolve the degeneracy between Earth and planet orbital effects by imposing priors from a Galactic model that specifies the positions and velocities of lenses and sources and a Kepler model of orbits. The 90% confidence intervals for the distance, semi-major axis, and period of the planet are 3.5 kpc < D_L < 7.9 kpc, 1.1 AU < a < 2.7AU, and 3.8 yr < P < 7.6 yr, respectively.Comment: 20 pages including 8 figures. A&A 529 102 (2011

    Microlensing Event MOA-2007-BLG-400: Exhuming the Buried Signature of a Cool, Jovian-Mass Planet

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    We report the detection of the cool, Jovian-mass planet MOA-2007-BLG-400Lb. The planet was detected in a high-magnification microlensing event (with peak magnification A_max = 628) in which the primary lens transited the source, resulting in a dramatic smoothing of the peak of the event. The angular extent of the region of perturbation due to the planet is significantly smaller than the angular size of the source, and as a result the planetary signature is also smoothed out by the finite source size. Thus the deviation from a single-lens fit is broad and relatively weak (~ few percent). Nevertheless, we demonstrate that the planetary nature of the deviation can be unambiguously ascertained from the gross features of the residuals, and detailed analysis yields a fairly precise planet/star mass ratio of q = 0.0026+/-0.0004, in accord with the large significance (\Delta\chi^2=1070) of the detection. The planet/star projected separation is subject to a strong close/wide degeneracy, leading to two indistinguishable solutions that differ in separation by a factor of ~8.5. Upper limits on flux from the lens constrain its mass to be M < 0.75 M_Sun (assuming it is a main-sequence star). A Bayesian analysis that includes all available observational constraints indicates a primary in the Galactic bulge with a mass of ~0.2-0.5 M_Sun and thus a planet mass of ~ 0.5-1.3 M_Jupiter. The separation and equilibrium temperature are ~0.6-1.1AU (~5.3-9.7AU) and ~103K (~34K) for the close (wide) solution. If the primary is a main-sequence star, follow-up observations would enable the detection of its light and so a measurement of its mass and distance.Comment: 30 pages, 6 figures, Submitted to Ap
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