22,187 research outputs found

    Una mirada a un grupo de nombres de lugar de reciente creación en un municipio español: algunas semejanzas y diferencias con los topónimos antiguos

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    The present work is focused on toponyms of recent creation. These new place names have generally received less attention among scholars than those with a long history, which have often generated passionate debates and academic papers about their origins. The group analyzed here was discarded from the index list resulting from a toponymy survey made in the village of Gata (Cáceres) in 2014. They are less than one hundred years old, and do not appear to be registered as toponyms in any known written source. However, their analysis reveals that the necessity for a social community to give names to the places it inhabits, and the process for the creation of new toponyms has essentially not changed for centuries.El presente trabajo se centra en los topónimos de reciente creación. Este grupo ha recibido generalmente menos atención por parte de los investigadores que aquellos otros que cuentan con una historia más larga, los cuales han sido con frecuencia objeto de apasionados debates acerca de su origen y generado numerosos trabajos académicos. La nómina de los aquí analizados está formada por el grupo de los no tomados en consideración para formar porte del corpus topónimo de Gata (Cáceres) efectuado en 2014 por tener menos de un siglo de antigüedad y no aparecer en ninguna de las fuentes escritas consultadas. Sim embargo, su análisis revela que para una comunidad rural la necesidad de darle un nombre a los lugares de su entorno y el proceso de creación de nuevos topónimos no ha variado sustancialmente desde la antigüedad

    A Next-to-Minimal Supersymmetric Model of Hybrid Inflation

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    We propose a model of inflation based on a simple variant of the NMSSM, called ϕ\phiNMSSM, where the additional singlet ϕ\phi plays the role of the inflaton in hybrid (or inverted hybrid) type models. As in the original NMSSM, the ϕ\phiNMSSM solves the μ\mu problem of the MSSM via the VEV of a gauge singlet NN, but unlike the NMSSM does not suffer from domain wall problems since the offending Z3Z_3 symmetry is replaced by an approximate Peccei-Quinn symmetry which also solves the strong CP problem, and leads to an invisible axion with interesting cosmological consequences. The PQ symmetry may arise from a superstring model with an exact discrete Z3×Z5Z_3 \times Z_5 symmetry after compactification. The model predicts a spectral index n=1n=1 to one part in 101210^{12}.Comment: 17 pages, Latex; note added, accepted for Phys. Lett.

    Palomar/Las Campanas Imaging Atlas of Blue Compact Dwarf Galaxies: II. Surface Photometry and the Properties of the Underlying Stellar Population

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    We present the results from an analysis of surface photometry of B, R, and Halpha images of a total of 114 nearby galaxies drawn from the Palomar/Las Campanas Imaging Atlas of Blue Compact Dwarf galaxies. Surface brightness and color profiles for the complete sample have been obtained. We determine the exponential and Sersic profiles that best fit the surface brightness distribution of the underlying stellar population detected in these galaxies. We also compute the (B-R) color and total absolute magnitude of the underlying stellar population and compared them to the integrated properties of the galaxies in the sample. Our analysis shows that the (B-R) color of the underlying population is systematically redder than the integrated color, except in those galaxies where the integrated colors are strongly contaminated by line and nebular-continuum emission. We also find that galaxies with relatively red underlying stellar populations (typically (B-R)>~1mag) show structural properties compatible with those of dwarf elliptical galaxies (i.e. a smooth light distribution, fainter extrapolated central surface brightness and larger scale lengths than BCD galaxies with blue underlying stellar populations). At least ~15% of the galaxies in the sample are compatible with being dwarf elliptical (dE) galaxies experiencing a burst of star formation. For the remaining BCD galaxies in the sample we do not find any correlation between the recent star formation activity and their structural differences with respect to other types of dwarf galaxies.Comment: 35 pages, 6 figures, accepted for publication in ApJS. Postscript files of panels f1a-f1o of figure 1 are available online at http://www.ociw.edu/~agpaz/astro-ph/apjs2004

    A Bosonic Analog of a Topological Dirac Semi-Metal: Effective Theory, Neighboring Phases, and Wire Construction

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    We construct a bosonic analog of a two-dimensional topological Dirac Semi-Metal (DSM). The low-energy description of the most basic 2D DSM model consists of two Dirac cones at positions ±k0\pm\mathbf{k}_0 in momentum space. The local stability of the Dirac cones is guaranteed by a composite symmetry Z2TIZ_2^{\mathcal{TI}}, where T\mathcal{T} is time-reversal and I\mathcal{I} is inversion. This model also exhibits interesting time-reversal and inversion symmetry breaking electromagnetic responses. In this work we construct a bosonic version by replacing each Dirac cone with a copy of the O(4)O(4) Nonlinear Sigma Model (NLSM) with topological theta term and theta angle θ=±π\theta=\pm \pi. One copy of this NLSM also describes the gapless surface termination of the 3D Bosonic Topological Insulator (BTI). We compute the time-reversal and inversion symmetry breaking electromagnetic responses for our model and show that they are twice the value one gets in the DSM case matching what one might expect from, for example, a bosonic Chern insulator. We also investigate the stability of the BSM model and find that the composite Z2TIZ_2^{\mathcal{TI}} symmetry again plays an important role. Along the way we clarify many aspects of the surface theory of the BTI including the electromagnetic response, the charges and statistics of vortex excitations, and the stability to symmetry-allowed perturbations. We briefly comment on the relation between the various descriptions of the O(4)O(4) NLSM with θ=π\theta=\pi used in this paper (a dual vortex description and a description in terms of four massless fermions) and the recently proposed dual description of the BTI surface in terms of 2+12+1 dimensional Quantum Electrodynamics with two flavors of fermion (N=2N=2 QED3_3). In a set of four Appendixes we review some of the tools used in the paper, and also derive some of the more technical results.Comment: 33 pages, 4 appendixes, v2: small corrections and added references, v3: new section added (Sec. VI) and additional references. To appear in PR

    Environmental Changes and the Dynamics of Musical Identity

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    Musical tastes reflect our unique values and experiences, our relationships with others, and the places where we live. But as each of these things changes, do our tastes also change to reflect the present, or remain fixed, reflecting our past? Here, we investigate how where a person lives shapes their musical preferences, using geographic relocation to construct quasi-natural experiments that measure short- and long-term effects. Analyzing comprehensive data on over 16 million users on Spotify, we show that relocation within the United States has only a small impact on individuals' tastes, which remain more similar to those of their past environments. We then show that the age gap between a person and the music they consume indicates that adolescence, and likely their environment during these years, shapes their lifelong musical tastes. Our results demonstrate the robustness of individuals' musical identity, and shed new light on the development of preferences.Comment: Accepted to be published at ICWSM'1

    Tunable ring resonator filter for OFDM Transmission systems

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    A novel tunable filter is theoretically demonstrated. It is based on a ring resonator with an amplifier and a noise filter in the loop. This optoelectronic device has potential as a high-sensitivity receiver and as a tunable demultiplexer in OFDM transmission systems.Publicad

    The braking indices in pulsar emission models

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    Using the method proposed in a previous paper, we calculate pulsar braking indices in the models with torque contributions from both inner and outer accelerating regions, assuming that the interaction between them is negligible. We suggest that it is likely that the inverse Compton scattering induced polar vacuum gap and the outer gap coexist in the pulsar magnetosphere. We include the new near threshold vacuum gap models with curvature-radiation and inverse Compton scattering induced cascades, respectively; and find that these models can well reproduce the measured values of the braking indices.Comment: A&Ap accepted, or at http://vega.bac.pku.edu.cn/~rxxu/publications/index_P.ht
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