91 research outputs found
A refined analysis of the low-mass eclipsing binary system T-Cyg1-12664
The observational mass-radius relation of main sequence stars with masses
between ~0.3 and 1.0 Msun reveals deviations between the stellar radii
predicted by models and the observed radii of stars in detached binaries. We
generate an accurate physical model of the low-mass eclipsing binary
T-Cyg1-12664 in the Kepler mission field to measure the physical parameters of
its components and to compare them with the prediction of theoretical stellar
evolution models. We analyze the Kepler mission light curve of T-Cyg1-12664 to
accurately measure the times and phases of the primary and secondary eclipse.
In addition, we measure the rotational period of the primary component by
analyzing the out-of-eclipse oscillations that are due to spots. We accurately
constrain the effective temperature of the system using ground-based absolute
photometry in B, V, Rc, and Ic. We also obtain and analyze V, Rc, Ic
differential light curves to measure the eccentricity and the orbital
inclination of the system, and a precise Teff ratio. From the joint analysis of
new radial velocities and those in the literature we measure the individual
masses of the stars. Finally, we use the PHOEBE code to generate a physical
model of the system. T-Cyg1-12664 is a low eccentricity system, located
d=360+/-22 pc away from us, with an orbital period of P=4.1287955(4) days, and
an orbital inclination i=86.969+/-0.056 degrees. It is composed of two very
different stars with an active G6 primary with Teff1=5560+/-160 K,
M1=0.680+/-0.045 Msun, R1=0.799+/-0.017 Rsun, and a M3V secondary star with
Teff2=3460+/-210 K, M2=0.376+/-0.017 Msun, and R2=0.3475+/-0.0081 Rsun. The
primary star is an oversized and spotted active star, hotter than the stars in
its mass range. The secondary is a cool star near the mass boundary for fully
convective stars (M~0.35 Msun), whose parameters appear to be in agreement with
low-mass stellar model.Comment: 18 pages, 15 figures, 15 table
Estudio clínico morfológico de la deformación del borde dorsal del cuello del burro de raza andaluza
The aim of this study was to a clinical, morphological of deformation dorsal neck edge on donkeys Andalusian in Bodonal de la Sierra, Extremadura, Spain. We studied a total of 31 donkeys. Clinical examination was performed and morphological considering weight and body condition was measured cervical perimeter. Deformation of the dorsal edge of the neck in all cases studied was evident. Morphological study was to consider the deformation of the dorsal edge of the neck considering the crest of the neck (score of 1 to 5) evidenced. 0 and 1 score-no donkey under these categories. Score 2 - 42 % Score. 3 - 32% score. 4 - 3 % and score 5 - 23%. The statistical results of the peso versus the cervical neck circumference showed a correlation coefficient of 0.773 and the score grade obese neck and body condition was 0.240. In conclusion lesions consistent with deformation of the dorsal edge of the neck in Andalusian breed donkeys were observed.Se plantea como objetivo un estudio clínico morfológico de la deformación del borde dorsal del cuello en burros de raza Andaluza en Bodonal de la Sierra, Extremadura-España. Fueron estudiados un total de 31 burros. Se practicó un examen clínico y morfológico considerando condición corporal peso y se midió el perímetro cervical. Se evidenció deformación del borde dorsal del cuello en todos los casos estudiados. El estudio morfológico para considerar la deformación del borde dorsal del cuello considerando la cresta de la nuca (puntuación del 1 al 5) evidencio: para Puntuación 0 y 1.- ningún burro bajo estas categorías. Puntuación 2.- 42%, Puntuación 3.- 32%, Puntuación 4.- 3% y Puntuación 5.- 23%. Los resultados estadísticos del peso versus el perímetro cervical del cuello presentaron un coeficiente de correlación de 0.773 y para el grado puntuación del cuello obeso y condición corporal fue de 0.240. En conclusión se observaron lesiones compatibles con la deformación del borde dorsal del cuello en burros de raza Andaluza
Exploring the circumstellar environment of the young eruptive star V2492 Cyg
Context. V2492 Cyg is a young eruptive star that went into outburst in 2010.
The near-infrared color changes observed since the outburst peak suggest that
the source belongs to a newly defined sub-class of young eruptive stars, where
time-dependent accretion and variable line-of-sight extinction play a combined
role in the flux changes.
Aims. In order to learn about the origin of the light variations and to
explore the circumstellar and interstellar environment of V2492 Cyg, we
monitored the source at ten different wavelengths, between 0.55 \mu m and 2.2
\mu m from the ground and between 3.6 \mu m and 160 \mu m from space.
Methods. We analyze the light curves and study the color-color diagrams via
comparison with the standard reddening path. We examine the structure of the
molecular cloud hosting V2492 Cyg by computing temperature and optical depth
maps from the far-infrared data.
Results. We find that the shapes of the light curves at different wavelengths
are strictly self-similar and that the observed variability is related to a
single physical process, most likely variable extinction. We suggest that the
central source is episodically occulted by a dense dust cloud in the inner
disk, and, based on the invariability of the far-infrared fluxes, we propose
that it is a long-lived rather than a transient structure. In some respects,
V2492 Cyg can be regarded as a young, embedded analog of UX Orionis-type stars.
Conclusions. The example of V2492 Cyg demonstrates that the light variations
of young eruptive stars are not exclusively related to changing accretion. The
variability provided information on an azimuthally asymmetric structural
element in the inner disk. Such an asymmetric density distribution in the
terrestrial zone may also have consequences for the initial conditions of
planet formation.Comment: 9 pages, 7 figures, 2 online tables, accepted for publication in A&
Dissecting the long-term emission behaviour of the BL Lac object Mrk 421
We report on long-term multiwavelengthmonitoring of blazar Mrk 421 by the GLAST-AGILE
Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and
Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in
the period 2007–2015, characterized by several extreme flares. The ratio between the optical,
X-ray and γ -ray fluxes is very variable. The γ -ray flux variations show a fair correlation with
the optical ones starting from 2012.We analyse spectropolarimetric data and find wavelengthdependence
of the polarization degree (P), which is compatible with the presence of the
host galaxy, and no wavelength dependence of the electric vector polarization angle (EVPA).
Optical polarimetry shows a lack of simple correlation between P and flux and wide rotations of
the EVPA.We build broad-band spectral energy distributions with simultaneous near-infrared
and optical data from the GASP-WEBT and ultraviolet and X-ray data from the Swift satellite.
They show strong variability in both flux and X-ray spectral shape and suggest a shift of
the synchrotron peak up to a factor of ∼50 in frequency. The interpretation of the flux and
spectral variability is compatible with jet models including at least two emitting regions that
can change their orientation with respect to the line of sight.http://10.0.4.69/mnras/stx2185Accepted manuscrip
Tutorial action in the EHEA at the Faculty of Pharmacy of us: 4 years of experience of a student mentoring program
La Facultad de Farmacia de la Universidad de Sevilla (US) tiene en marcha un Programa de Alumnos Tutores desde 2006/07 con el objetivo de que alumnos de cursos superiores (AATT) tutelen a alumnos de nuevo ingreso (1x3). Pretende generar una actitud responsable en los AATT y favorecerles el desarrollo de habilidades sociales, objetivos cualitativos dentro de la educación universitaria que sirven como preparación previa a su inserción en el mundo laboral. La actividad es supervisada por Profesores Tutores (1x3) que analizan la evolución de ambos grupos de alumnos. Es una supervisión activa a través de distintas vías de acción para ayudar a la consecución de objetivos, tales como entrevistas periódicas, revisión de informes, acciones de apoyo como charlas sobre técnicas de estudio, coloquios sobre salidas laborales, exposiciones de las experiencias personales de algunos alumnos recientemente egresados, gestión estratégica de búsqueda de empleo, elaboración de portafolios,…
Con respecto a la evolución del programa, el número de profesores ha crecido moderadamente llegando a una situación estable, mientras que el número de alumnos, tanto tutores como tutelados, ha crecido en un ritmo constante acorde a las restricciones indicadas. Los resultados son muy positivos, entendiéndose que el proyecto se enmarca en un contexto más cualitativo que cuantitativo y que el principal objetivo es el robustecimiento de la experiencia y asentar una dinámica de apoyo hacia los alumnos de nuevo ingreso y de planificación de tareas, tutela y responsabilidad en general de los alumnos tutores.The Faculty of Pharmacy of the University of Seville (US) has developed a Student Mentoring Program (from 2006/07 - present). The main objective of this project is that senior students act as Mentor Students for students at their first year in the University (1x3). It aims to generate a responsible attitude in mentor students and to promote the development of social skills, qualitative goals within higher education that serve as preparation prior to their integration into the world of work.
This activity is supervised by Mentor Professors (1x3) that analyze the evolution of both groups of students. It is an active monitoring through various actions such as regular interviews, review of reports, support operations such as lectures on study skills, seminars on job opportunities, statements of personal experiences of some recently graduated students, strategic management job search, portfolio development...
With regard to the development of the program, the number of Mentor Professors has grown moderately, reaching a stable condition, while the number of students, both tutor and supervised, has grown steadily in line with the restrictions indicated. The results are very positive, considering the more qualitative than quantitative character of the project and that the main objectives are the strengthening of the experience and the establishment of a dynamic support to the new students and scheduling and general responsibility for mentor students
The WEBT campaign on the BL Lac object PG 1553+113 in 2013. An analysis of the enigmatic synchrotron emission
A multifrequency campaign on the BL Lac object PG 1553+113 was organized by the Whole Earth Blazar Telescope (WEBT) in 2013 April-August, involving 19 optical, two near-IR, and three radio telescopes. The aim was to study the source behaviour at low energies during and around the high-energy observations by the Major Atmospheric Gamma-ray Imaging Cherenkov telescopes in April-July. We also analyse the UV and X-ray data acquired by the Swift and XMM-Newton satellites in the same period. The WEBT and satellite observations allow us to detail the synchrotron emission bump in the source spectral energy distribution (SED). In the optical, we found a general bluer-when-brighter trend. The X-ray spectrum remained stable during 2013, but a comparison with previous observations suggests that it becomes harder when the X-ray flux increases. The long XMM-Newton exposure reveals a curved X-ray spectrum. In the SED, the XMM-Newton data show a hard near-UV spectrum, while Swift data display a softer shape that is confirmed by previous Hubble Space Telescope/Cosmic Origins Spectrograph and International Ultraviolet Explorer observations. Polynomial fits to the optical-X-ray SED show that the synchrotron peak likely lies in the 4-30eV energy range, with a general shift towards higher frequencies for increasing X-ray brightness. However, the UV and X-ray spectra do not connect smoothly. Possible interpretations include: (i) orientation effects, (ii) additional absorption, (iii) multiple emission components, and (iv) a peculiar energy distribution of relativistic electrons. We discuss the first possibility in terms of an inhomogeneous helical jet mode
The extreme HBL behaviour of Markarian 501 during 2012
A multiwavelength campaign was organized to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on board the Swift and Fermi spacecraft, and the telescopes operated by the GASP-WEBT collaboration. Mrk 501 showed a very high energy (VHE) gamma-ray flux above 0.2 TeV of 0.5 times the Crab Nebula flux (CU) for most of the campaign. The highest activity occurred on 2012 June 9, when the VHE flux was 3 CU, and the peak of the high-energy spectral component was found to be at 2 TeV. This study reports very hard X-ray spectra, and the hardest VHE spectra measured to date for Mrk 501. The fractional variability was found to increase with energy, with the highest variability occurring at VHE, and a significant correlation between the X-ray and VHE bands. The unprecedentedly hard X-ray and VHE spectra measured imply that their low- and high-energy components peaked above 5 keV and 0.5 TeV, respectively, during a large fraction of the observing campaign, and hence that Mrk 501 behaved like an extreme high-frequency- peaked blazar (EHBL) throughout the 2012 observing season. This suggests that being an EHBL may not be a permanent characteristic of a blazar, but rather a state which may change over time. The one-zone synchrotron self-Compton (SSC) scenario can successfully describe the segments of the SED where most energy is emitted, with a significant correlation between the electron energy density and the VHE gamma-ray activity, suggesting that most of the variability may be explained by the injection of high-energy electrons. The one-zone SSC scenario used reproduces the behaviour seen between the measured X-ray and VHE gamma-ray fluxes, and predicts that the correlation becomes stronger with increasing energy of the X-rays
Large-scale study on virological and serological prevalence of SARS-CoV-2 in cats and dogs in Spain
The disease produced by the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) is currently one of the primary concerns worldwide. Knowing the zoonotic origin of the disease and that several animal species, including dogs and cats, are susceptible to viral infection, it is critical to assess the relevance of pets in this pandemic. Here, we performed a large-scale study on SARS-CoV-2 serological and viral prevalence in cats and dogs in Spain in order to elucidate their role and susceptibility. Samples from animals in contact with COVID-19 positive people and/or compatible symptoms (n = 492), as well as from random animals (n = 1024), were taken. Despite the large number of animals analyzed, only 12 animals (eight dogs and four cats), which represents 0.79% of the total analyzed animals (n = 1516), were positive for viral SARS-CoV-2 RNA detection by reverse transcription quantitative PCR (RT-qPCR) in which viral isolation was possible in four animals. We detected neutralizing antibodies in 34 animals, four of them were also positive for PCR. This study evidences that pets are susceptible to SARS-CoV-2 infection in natural conditions but at a low level, as evidenced by the low percentage of positive animals detected, being infected humans the main source of infection. However, the inclusion of animals in the surveillance of COVID-19 is still recommended.Institute of Health Carlos III (ISCIII), Grant/Award Number: COV20/01385Peer reviewe
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