4,224 research outputs found

    LabelTranslator: A Tool to Automatically Localize an Ontology

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    This demo proposal briefly presents LabelTranslator, a system that suggests translations of ontology labels, with the purpose of localizing ontologies. LabelTranslator takes as input an ontology whose labels are described in a source natural language and obtains the most probable translation of each ontology label into a target natural language.Our main contribution is the automatization of this process, which reduces human efforts to localize manually the ontology

    Cosmological Constant and Local Gravity

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    We discuss the linearization of Einstein equations in the presence of a cosmological constant, by expanding the solution for the metric around a flat Minkowski space-time. We demonstrate that one can find consistent solutions to the linearized set of equations for the metric perturbations, in the Lorentz gauge, which are not spherically symmetric, but they rather exhibit a cylindrical symmetry. We find that the components of the gravitational field satisfying the appropriate Poisson equations have the property of ensuring that a scalar potential can be constructed, in which both contributions, from ordinary matter and Λ>0\Lambda > 0, are attractive. In addition, there is a novel tensor potential, induced by the pressure density, in which the effect of the cosmological constant is repulsive. We also linearize the Schwarzschild-de Sitter exact solution of Einstein's equations (due to a generalization of Birkhoff's theorem) in the domain between the two horizons. We manage to transform it first to a gauge in which the 3-space metric is conformally flat and, then, make an additional coordinate transformation leading to the Lorentz gauge conditions. We compare our non-spherically symmetric solution with the linearized Schwarzschild-de Sitter metric, when the latter is transformed to the Lorentz gauge, and we find agreement. The resulting metric, however, does not acquire a proper Newtonian form in terms of the unique scalar potential that solves the corresponding Poisson equation. Nevertheless, our solution is stable, in the sense that the physical energy density is positive.Comment: 7 pages revtex, no figures; discussion on light bending added, no effect on conclusions, version to appear in Physical Review D

    Search for new physics with neutrinos at Radioactive Ion Beam facilities

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    We propose applications of Radioactive Ion Beam facilities to investigate physics beyond the Standard Model. In particular, we focus on the possible measurement of coherent neutrino-nucleus scattering and on a search for sterile neutrinos, by means of a low energy beta-beam with a Lorentz boost factor γ≈1\gamma \approx 1. In the considered setup the collected radioactive ions are sent inside a 4π\pi detector. For the first application we provide the number of events associated with neutrino-nucleus coherent scattering, when the detector is filled in with a noble liquid. For the sterile search we consider that the spherical detector is filled in with a liquid scintillator, and that the neutrino detection channel is inverse-beta decay. We provide the exclusion curves for the sterile neutrino mixing parameters, based upon the 3+1 formalism, depending upon the achievable ion intensity. Our results are obtained both from total rates, and including spectral information with binning in energy and in distance. The proposed experiment represents a possible alternative to clarify the current anomalies observed in neutrino experiments.Comment: 9 pages, 6 figures. v2 - added 2 figure

    Classic Liberal Philosophers and their Contributions to Democracy & Justice: Discourses on Freedom, Equality, Reason, and Law

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    The goal of this article is to review the ideas set forth by classic liberal philosophers which contributed to the establishment of democratic values and the institutionalization of reason as a method. The emphasis is to examine the critical ideas which led to the study of natural law and civil society, focusing on freedom, equality, reason, and law. This review will provide social science students the foundational knowledge to understand the goals of human progress as expounded by classic liberal philosophers, as well as understanding reason as inextricable to democracy and the advancement of knowledge. The ideals set forth by the classic liberal philosophers such as Locke, Montesquieu, Rousseau, Wollstonecraft, and Condorcet, have left a legacy of justice from which we can continue to progress as citizens and students

    Ermakov Systems with Multiplicative Noise

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    Using the Euler-Maruyama numerical method, we present calculations of the Ermakov-Lewis invariant and the dynamic, geometric, and total phases for several cases of stochastic parametric oscillators, including the simplest case of the stochastic harmonic oscillator. The results are compared with the corresponding numerical noiseless cases to evaluate the effect of the noise. Besides, the noiseless cases are analytic and their analytic solutions are briefly presented. The Ermakov-Lewis invariant is not affected by the multiplicative noise in the three particular examples presented in this work, whereas there is a shift effect in the case of the phasesComment: 12 pages, 4 figures, 22 reference

    Twisters and signed fundamental domains for number fields

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    We give a signed fundamental domain for the action on R+r1×C∗r2\mathbb{R}^{r_1}_+\times{\mathbb{C}^*}^{r_2} of the totally positive units E+E_+ of a number field kk of degree n=r1+2r2n=r_1+2r_2 which we assume is not totally complex. Here r1r_1 and r2r_2 denote the number of real and complex places of kk and R+\mathbb{R}_+ denotes the positive real numbers. The signed fundamental domain consists of nn-dimensional kk-rational cones CαC_\alpha, each equipped with a sign μα=±1\mu_\alpha=\pm1, with the property that the net number of intersections of the cones with any E+E_+-orbit is 1. The cones CαC_\alpha and the signs μα\mu_\alpha are explicitly constructed from any set of fundamental totally positive units and a set of 3r23^{r_2} "twisters", i.e. elements of kk whose arguments at the r2r_2 complex places of kk are sufficiently varied. Introducing twisters gives us the right number of generators for the cones CαC_\alpha and allows us to make the CαC_\alpha turn in a controlled way around the origin at each complex embedding

    Using the Unispec to Test the Difference in Reflectance of the Yellow Petals of Encelia californica, Encelia farinosa, and Spartium junceum

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    The reflectance spectrum of three yellow flowered species (Encelia californica, Encelia farinosa, and Spartium junceum), all grown on the coast of California, was tested to determine if reflectance among the yellow flowers was significantly different. It was hypothesized that there would be a significant difference in reflectance in the 400-700 nm wavebands for the three different species of flowers which all possess yellow petals. Using a Unispec Spectral Analysis System to obtain reflectance spectra for 12 yellow petals of three flowered species, a custom index was created in order to observe differences in the yellow color of the petals, which may account for pollinator attraction and possible natural selection based evolution (N. M. Waser et. al. 1983). The index accounted for a specific range of visible light from approximately 600-700 nm, where the largest reflectance differences occurred among the three tested species. Based on the obtained measurements of the 36 different flower reflection spectra, it was observed that the reflectance for the three different species of yellow flowers was significantly different for not only the created Mariam-Valerie Index, MVI, but also for the Normalized Difference Vegetation Index, NDVI, as well. This difference among similar species may have biological importance, as this significance may account for natural selection based evolution of the flowers which could include specific pollinator selection and increased survival of these particular plants among other yellow flowered species

    New ultracool subdwarfs identified in large-scale surveys using Virtual Observatory tools: II. SDSS DR7 vs UKIDSS LAS DR6, SDSS DR7 vs UKIDSS LAS DR8, SDSS DR9 vs UKIDSS LAS DR10, and SDSS DR7 vs 2MASS

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    We aim at developing an efficient method to search for late-type subdwarfs (metal-depleted dwarfs with spectral types >M5) to improve the current statistics. Our objectives are: improve our knowledge of metal-poor low-mass dwarfs, bridge the gap between the late-M and L types, determine their surface density, and understand the impact of metallicity on the stellar and substellar mass function. We carried out a search cross-matching the SDSS, 2MASS, and UKIDSS using STILTS, Aladin, and Topcat. We considered different photometric and proper motion criteria for our selection. We identified 29 and 71 late-type subdwarf candidates in each cross-correlation over 8826 and 3679 square degrees, respectively. We obtained low-resolution optical spectra for 71 of our candidates with GTC, NOT, and VLT and retrieved spectra for 30 candidates from the SDSS spectroscopic database. We classified 92 candidates based on 101 optical spectra using two methods: spectral indices and comparison with templates of known subdwarfs. We confirmed 86% and 94% of the candidates as late-type subdwarfs from the SDSS vs 2MASS and SDSS vs UKIDSS cross-matches, respectively. These subdwarfs have spectral types ranging between M5 and L0.5 and SDSS magnitudes in the r=19.4-23.3 mag range. Our new late-type M discoveries include 49 subdwarfs, 25 extreme subdwarfs, six ultrasubdwarfs, one subdwarf/extreme subdwarf, and two dwarfs/subdwarfs. We derived a surface density of late-type subdwarfs of 0.040−0.007+0.012^{+0.012}_{-0.007} per square degree in the SDSS DR7 vs UKIDSS LAS DR10 cross-match. We also checked the AllWISE photometry of known and new subdwarfs and found that mid-infrared colours of M subdwarfs do not appear to differ from their solar-metallicity counterparts of similar spectral types. However, the J-W2 and J-W1 colours are bluer for lower metallicity dwarfs. (abstract strongly abridged)Comment: 28 pages, 4 Tables, 10 figures, 1 appendix. Accepted to A&A. Photometry and spectra available in a dedicated archive on late-type subdwarfs at http://svo2.cab.inta-csic.es/vocats/ltsa
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