22,918 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
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
We propose a model of inflation based on a simple variant of the NMSSM,
called NMSSM, where the additional singlet plays the role of the
inflaton in hybrid (or inverted hybrid) type models. As in the original NMSSM,
the NMSSM solves the problem of the MSSM via the VEV of a gauge
singlet , but unlike the NMSSM does not suffer from domain wall problems
since the offending 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 symmetry after
compactification. The model predicts a spectral index to one part in
.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
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
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 in momentum space.
The local stability of the Dirac cones is guaranteed by a composite symmetry
, where is time-reversal and 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
Nonlinear Sigma Model (NLSM) with topological theta term and theta angle
. 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
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 NLSM with
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 dimensional Quantum Electrodynamics with two flavors
of fermion ( QED). 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
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
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
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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