4,537 research outputs found
High-energy signatures of binary systems of supermassive black holes
Context. Binary systems of supermassive black holes are expected to be strong
sources of long gravitational waves prior to merging. These systems are good
candidates to be observed with forthcoming space-borne detectors. Only a few of
these systems, however, have been firmly identified to date.
Aims. We aim at providing a criterion for the identification of some
supermassive black hole binaries based on the characteristics of the
high-energy emission of a putative relativistic jet launched from the most
massive of the two black holes.
Methods. We study supermassive black hole binaries where the less massive
black hole has carved an annular gap in the circumbinary disk, but nevertheless
there is a steady mass flow across its orbit. Such a perturbed disk is hotter
and more luminous than a standard thin disk in some regions. Assuming that the
jet contains relativistic electrons, we calculate its broadband spectral energy
distribution focusing on the inverse Compton up-scattering of the disk photons.
We also compute the opacity to the gamma rays produced in the jet by photon
annihilation with the disk radiation and take into account the effects of the
anisotropy of the target photon field as seen from the jet.
Results. We find that the excess of low-energy photons radiated by the
perturbed disk causes an increment in the external Compton emission from the
jet in the X-ray band, and a deep absorption feature at energies of tens of
TeVs for some sets of parameters. According to our results, observations with
Cherenkov telescopes might help in the identification of supermassive black
hole binaries, especially those black hole binaries that host primaries from
tens to hundreds of million of solar masses.Comment: 12 pages, 11 figures, accepted for publication in Astronomy &
Astrophysic
Evidences of evanescent Bloch waves in Phononic Crystals
We show both experimentally and theoretically the evanescent behaviour of
modes in the Band Gap (BG) of finite Phononic Crystal (PC). Based on
experimental and numerical data we obtain the imaginary part of the wave vector
in good agreement with the complex band structures obtained by the Extended
Plane Wave Expansion (EPWE). The calculated and measured acoustic field of a
localized mode out of the point defect inside the PC presents also evanescent
behaviour. The correct understanding of evanescent modes is fundamental for
designing narrow filters and wave guides based on Phononic Crystals with
defects.Comment: 8 pages, 3 figure
Axiomatic foundations of nonrelativistic quantum mechanics: a realistic approach
A realistic axiomatic formulation of nonrelativistic quantum mechanics for a single microsystem with spin is presented, from which the most important theorems of the theory can be deduced. In comparison with previous formulations, the formal aspect has been improved by the use of certain mathematical theories, such as the theory of equipped spaces, and group theory. The standard formalism is naturally obtained from the latter, starting from a central primitive concept: the Galilei group
The nature of supernovae 2010O and 2010P in Arp 299 - II. Radio emission
We report radio observations of two stripped-envelope supernovae (SNe), 2010O
and 2010P, which exploded within a few days of each other in the luminous
infrared galaxy Arp 299. Whilst SN 2010O remains undetected at radio
frequencies, SN 2010P was detected (with an astrometric accuracy better than 1
milli arcsec in position) in its optically thin phase in epochs ranging from ~1
to ~3yr after its explosion date, indicating a very slow radio evolution and a
strong interaction of the SN ejecta with the circumstellar medium. Our
late-time radio observations toward SN 2010P probe the dense circumstellar
envelope of this SN, and imply a mass-loss rate (Msun/yr) to wind velocity (in
units of 10 km/s) ratio of (3.0-5.1)E-05, with a 5 GHz peak luminosity of
~1.2E+27 erg/s/Hz on day ~464 after explosion. This is consistent with a Type
IIb classification for SN 2010P, making it the most distant and most slowly
evolving Type IIb radio SN detected to date.Comment: 14 pages, 8 tables and 7 figures. Accepted for publication in MNRA
Analysis of the wave propagation properties of a periodic array of rigid cylinders perpendicular to a finite impedance surface
The effect of the presence of a finite impedance surface on the wave
propagation properties of a two-dimensional periodic array of rigid cylinders
with their axes perpendicular to the surface is both numerically and
experimentally analyzed in this work. In this realistic situation both the
incident and the scattered waves interact with these two elements, the surface
and the array. The interaction between the excess attenuation effect, due to
the destructive interference produced by the superposition of the incident wave
and the reflected one by the surface, and the bandgap, due to the periodicity
of the array, is fundamental for the design of devices to control the
transmission of waves based on periodic arrays. The most obvious application is
perhaps the design of Sonic Crystals Noise Barriers. Two different finite
impedance surfaces have been analyzed in the work in order to observe the
dependence of the wave propagation properties on the impedance of the surface
Relación de la calidad de vida profesional y el burnout en médicos de atención primaria
ObjetivoConocer la relación, si es que la hay, entre la calidad de vida profesional (CVP) y burnout de facultativos de atención primaria.DiseñoEstudio transversal mediante cuestionario CVP-35 y MBI (Maslach Burnout Inventory), por correo postal.ÁmbitoTres centros urbanos y 3 zonas de atención rural. Participó un total de 131 profesionalesMedicionesDel CVP-35 se obtienen puntuaciones que van de 0 (mínimo) a 10 (máximo). El cuestionario Maslach clasifica en nivel alto, medio y bajo de cada dimensión.ResultadosContestó a la encuesta el 71,7%. La edad media era de 44 años y la media de tarjetas sanitarias, 1.339. El número de consultas/día fue de 37; en cuanto las visitas domiciliarias, realizaban una diaria. El valor medio de la CVP fue de 4,48 (intervalo de confianza [IC] del 95%, 4,08-4,88). La percepción de la demanda tuvo una puntuación de 5,9 (IC del 95%, 5,6-6,1); la motivación intrínseca del profesional se situó en 6,5 (IC del 95%, 6,2-6,7) y el apoyo de los directivos en 3,8 (IC del 95%, 3,6-4,1). En cuanto al cuestionario MBI, se observó una despersonalización alta en el 54,3%, cansancio emocional alto en un 56,2% y realización personal alta en el 9,3%. La correlación mayor fue entre las demandas en el puesto y el cansancio emocional (r=0,6; p<0,0001), la motivación intrínseca y la realización personal (r=0,46; p<0,0001) y la calidad de vida profesional frente al cansancio emocional (r=−0,4; p<0,0005).ConclusionesLa CVP y el burnout miden dimensiones diferentes pero relacionadas. Por tanto, su utilidad es diferente en función de los objetivos. Con estos instrumentos se pueden identificar elementos clave de la gestión de personas que pueden mejorar la calidad de vida profesional.ObjectiveTo know the relationship, if this exists, between the quality of professional life (CPL) and the burnout of primary health care staff.DesignTransversal study employing CVP-35 test and MBI (Maslach Burnout Inventory), both sent by postmail.Setting3 urban centers and 3 rural centers. Total: 131 professionals.MeasuresIn the CVP-35 test, scores from 0 (minimum) to 100 (maximum) are obtained. Maslach categorised each dimension into high, medium and low level.Results71.7% answered. Medium age 44 years, average of 1339 sanitary cards. The number of visits/day was 37, home visits 1 per day. The CVP average was 4.48 (95% CI, 4.08-4.88). The damage perception in the post 5.9 (95% CI, 5.6-6.1); the professional intrinsic motivation 6.5 (95% CI, 6.2-6.7), and the manager support 3.8 (95% CI, 3.6-4.1). MBI: high depersonalization 54.3%, emotional exhaustion (r=0.6; P<.0001), intrinsic motivation, and personal accomplishment (r=0.46; P<.0001) and profesional quality of life front emotional fatigue (r= −0.4; P<.0005).ConclusionsCPL and burnout measure different but related dimensions. Therefore, its utility is dependent on the objectives. Target elements, which can improve the quality of professional life, can be identified from these tools
Estudio baropodométrico en pacientes tratados mediante artroplastia total de rodilla
La patología artrósica de la rodilla condiciona una disminución de la carga del miembro afecto y
un patrón de apoyo con predominio generalmente del arco externo. El propósito de este estudio es determinar si
existe una modificación significativa de este patrón tras la implantación de una artroplastia total de rodilla (ATR)
primaria, recogiendo las presiones plantares de ambos pies mediante baropodometría electrónica previamente y 4
meses tras la cirugía, tanto en estática como en dinámica. Así, se analizan las presiones plantares de 30 pacientes,
21 mujeres y 9 hombres, intervenidos de ATR primaria en el Hospital Universitario Doctor Peset entre los años
2013 y 2015. También se ha determinado si existe una corrección del eje anatómico tras la cirugía. Utilizando test
no paramétricos (test de Wilcoxon para datos apareados, U de Mann-Whitney), observamos una modificación
significativa de dicho ángulo desde valores medianos de 1.2º de varo a 4.9º de valgo en el postoperatorio, una
disminución mediana de la presión plantar en ambos pies y una redistribución de la carga axial, aumentando en
el miembro intervenido. Concluimos que, 4 meses tras la cirugía, se produce una tendencia a la “normalización”
de la pisada en pacientes en los que se ha implantado una ATR, condicionado tanto por la mejora del dolor y la
funcionalidad como por la realineación del eje.Knee osteoarthritis determines a decrease of the load of the affected limb and a pattern usually
dominance of external support plantar arc. The purpose of this study is to determine whether a significant change
in this pattern is? after implantation of a primary total knee arthroplasty (TKA), measuring plantar pressures
in both feet by electronic baropodometry previously and 4 months after surgery, in static and dynamic. Plantar
pressures of 30 patients are analyzed, who underwent primary TKA at the University Hospital Doctor Peset
between 2013 and 2015. In addition, it has also been determined if there is a correction on the anatomical axis
after surgery. Using nonparametric test (Wilcoxon test for paired data, U Mann Whitney), we observed a significant
change in the angle from median values of 1.2º varus to 4.9º valgus postoperatively, a median decrease of
plantar pressure in both feet and a redistribution of axial load, increasing in the operated limb. We conclude that,
4 months after surgery, there is a tendency to “normalization” of the tread in patients undergoing TKA. This is
conditioned by improving pain and function as axis realignment occurs
NGC 6705 a young -enhanced Open Cluster from OCCASO data
The stellar [/Fe] abundance is sometimes used as a proxy for stellar
age, following standard chemical evolution models for the Galaxy, as seen by
different observational results. In this work we show that the Open Cluster
NGC6705/M11 has a significant -enhancement [/Fe] dex,
despite its young age (300 Myr), challenging the current paradigm. We use
high resolution (R) high signal-to-noise (70) spectra of 8 Red
Clump stars, acquired within the OCCASO survey. We determine very accurate
chemical abundances of several elements, using an equivalent width
methodology (Si, Ca and Ti), and spectral synthesis fits (Mg and O). We obtain
[Si/Fe]=, [Mg/Fe]=, [O/Fe]=,
[Ca/Fe]= and [Ti/Fe]=. Our results place these
cluster within the group of young [/Fe]-enhanced field stars recently
found by several authors in the literature. The ages of our stars have an
uncertainty of around 50 Myr, much more precise than for field stars. By
integrating the cluster's orbit in several non-axisymmetric Galactic
potentials, we establish the M11's most likely birth radius to lie between
6.8-7.5 kpc from the Galactic center, not far from its current position. With
the robust Open Cluster age scale, our results prove that a moderate
[/Fe]-enhancement is no guarantee for a star to be old, and that not
all -enhanced stars can be explained with an evolved blue straggler
scenario. Based on our orbit calculations, we further argue against a Galactic
bar origin of M11.Comment: 10 pages, 6 figures, accepted in A&
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