73 research outputs found

    Perturbations of Spacetime around a Stationary Rotating Cosmic String

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    We consider the metric perturbations around a stationary rotating Nambu-Goto string in Minkowski spacetime. By solving the linearized Einstein equations, we study the effects of azimuthal frame-dragging around the rotation axis and linear frame-dragging along the rotation axis, the Newtonian logarithmic potential, and the angular deficit around the string as the potential mode. We also investigate gravitational waves propagating off the string and propagating along the string, and show that the stationary rotating string emits gravitational waves toward the directions specified by discrete angles from the rotation axis. Waveforms, polarizations, and amplitudes which depend on the direction are shown explicitly.Comment: 30 pages, 6 figures; Minor corrections, references added, published version in Physical Review

    The radio to TeV orbital variability of the microquasar LSI+61303

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    Context: .The microquasar LS I +61 303 has recently been detected at TeV energies by the Cherenkov telescope MAGIC, presenting variability on timescales similar to its orbital period. This system has been intensively observed at different wavelengths during the last three decades, showing a very complex behavior along the orbit.Aims: .We aim to explain, using a leptonic model in the accretion scenario, the observed orbital variability and spectrum from radio to TeV energies of LS I +61 303.Methods: .We apply a leptonic model based on accretion of matter from the slow inhomogeneous equatorial wind of the primary star, assuming particle injection proportional to the accretion rate. The relativistic electron energy distribution within the binary system is computed taking into account convective/adiabatic and radiative losses. The spectral energy distribution (SED) has been calculated accounting for synchrotron and (Thomson/Klein Nishina -KN-) inverse Compton (IC) processes and the photon-photon absorption in the ambient photon fields. The angle dependence of the photon-photon and IC cross sections has been considered in the calculations.Results: .We reproduce the main features of the observed light curves from LS I +61 303 at radio, X-rays, high-energy (HE), and very high-energy (VHE) gamma-rays, and the whole spectral energy distribution.Conclusions: .Our model is able to explain the radio to TeV orbital variability taking into account that radiation along the orbit is strongly affected by the variable accretion rate, the magnetic field strength, and by the ambient photon field via dominant IC losses and photon-photon absorption at periastron.Fil: Bosch Ramon, Valentí. Universidad de Barcelona; EspañaFil: Paredes, Josep Maria. Universidad de Barcelona; EspañaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Ribó, Marc. Universidad de Barcelona; Españ

    Ontology Mapping of PATO to YATO for the improvement of interoperability of quality description

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    To facilitate broad interoperability for phenotype information between different ontological frameworks, we developed a reference ontology, PATO2YATO_Quality, with the careful mapping of terms of PATO which is a quality ontology commonly used for biological phenotype annotation to the latest top-level ontology, YATO, which represents advanced modeling of quality-related concepts. As a result, YATO framework enabled to describe changes of phenotypic qualities along the courses of time in ontologically correct way and sophisticated classification and representation of interrelationships among quality-related concepts to provide fully integration of qualitative values and quantitative values obtained from phenotyping experiments and advanced representation of more detailed quality description. Thus, PATO2YATO_Quality will contribute to advanced integration of phenotypic qualities

    Stationary Rotating Strings as Relativistic Particle Mechanics

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    Stationary rotating strings can be viewed as geodesic motions in appropriate metrics on a two-dimensional space. We obtain all solutions describing stationary rotating strings in flat spacetime as an application. These rotating strings have infinite length with various wiggly shapes. Averaged value of the string energy, the angular momentum and the linear momentum along the string are discussed.Comment: 20pages, 7 figure

    An Advanced Clinical Ontology

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    This article discusses a fundamental issues of medical ontology based on ontological theory. We focus on "anatomical structure of organs" and "abnormal states in the human body". On the basis of the investigation, we distinguish organ-specific types from those independent of any organ to maximize the explicitness of ontology. The next feature of our ontology is to allow on-demand reorganization of is-a hierarchy of diseases instead of one fixed hierarchy to cope with various viewpoints which physician might have. We also take care of the notorious issue related to conflict of is-a and part-of relations

    Domain Ontology Developments and their Utilization

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