32 research outputs found
PASTIS: Bayesian extrasolar planet validation. I. General framework, models, and performance
A large fraction of the smallest transiting planet candidates discovered by
the Kepler and CoRoT space missions cannot be confirmed by a dynamical
measurement of the mass using currently available observing facilities. To
establish their planetary nature, the concept of planet validation has been
advanced. This technique compares the probability of the planetary hypothesis
against that of all reasonably conceivable alternative false-positive (FP)
hypotheses. The candidate is considered as validated if the posterior
probability of the planetary hypothesis is sufficiently larger than the sum of
the probabilities of all FP scenarios. In this paper, we present PASTIS, the
Planet Analysis and Small Transit Investigation Software, a tool designed to
perform a rigorous model comparison of the hypotheses involved in the problem
of planet validation, and to fully exploit the information available in the
candidate light curves. PASTIS self-consistently models the transit light
curves and follow-up observations. Its object-oriented structure offers a large
flexibility for defining the scenarios to be compared. The performance is
explored using artificial transit light curves of planets and FPs with a
realistic error distribution obtained from a Kepler light curve. We find that
data support for the correct hypothesis is strong only when the signal is high
enough (transit signal-to-noise ratio above 50 for the planet case) and remains
inconclusive otherwise. PLATO shall provide transits with high enough
signal-to-noise ratio, but to establish the true nature of the vast majority of
Kepler and CoRoT transit candidates additional data or strong reliance on
hypotheses priors is needed.Comment: Accepted for publication in MNRAS; 23 pages, 11 figure
When Virtual Assistants Meet Teledermatology: Validation of a Virtual Assistant to Improve the Quality of Life of Psoriatic Patients
Teledermatology has given dermatologists a tool to track patients’ responses to therapy using images. Virtual assistants, the programs that interact with users through text or voice messages, could be used in teledermatology to enhance the interaction of the tool with the patients and healthcare professionals and the overall impact of the medication and quality of life of patients. As such, this work aimed to investigate the effectiveness of using a virtual assistant for teledermatology and its impact on the quality of life. We conducted surveys with the participants and measured the usability of the system with the System Usability Scale (SUS). A total of 34 participants (30 patients diagnosed with moderate-severe psoriasis and 4 healthcare professionals) were included in the study. The measurement of the improvement of quality of life was done by analyzing Psoriasis Quality of Life (PSOLIFE) and Dermatology Life Quality Index (DLQI) questionnaires. The results showed that, on average, the quality of life improved (from 63.8 to 64.8 for PSOLIFE (with a p-value of 0.66 and an effect size of 0.06) and 4.4 to 2.8 for DLQI (with a p-value of 0.04 and an effect size of 0.31)). Patients also used the virtual assistant to do 52 medical consultations. Moreover, the usability is above average, with a SUS score of 70.1. As supported by MMAS-8 results, adherence also improved slightly. Our work demonstrates the improvement of the quality of life with the use of a virtual assistant in teledermatology, which could be attributed to the sense of security or peace of mind the patients get as they can contact their dermatologists directly within the virtual assistant-integrated system
TrES-2: The First Transiting Planet in the Kepler Field
We announce the discovery of the second transiting hot Jupiter discovered by
the Trans-atlantic Exoplanet Survey. The planet, which we dub TrES-2, orbits
the nearby star GSC 03549-02811 every 2.47063 days. From high-resolution
spectra, we determine that the star has T_eff = 5960 +/- 100 K and log(g) = 4.4
+/- 0.2, implying a spectral type of G0V and a mass of 1.08 +0.11/-0.05 M_sun.
High-precision radial-velocity measurements confirm a sinusoidal variation with
the period and phase predicted by the photometry, and rule out the presence of
line-bisector variations that would indicate that the spectroscopic orbit is
spurious. We estimate a planetary mass of 1.28 +0.09/-0.04 M_Jup. We model B,
r, R, and I photometric timeseries of the 1.4%-deep transits and find a
planetary radius of 1.24 +0.09/-0.06 R_Jup. This planet lies within the field
of view of the NASA Kepler mission, ensuring that hundreds of upcoming transits
will be monitored with exquisite precision and permitting a host of
unprecedented investigations.Comment: Accepted for publication in ApJL. 15 pages, 2 figure
Política laboral y funcionamiento del mercado de trabajo en la Unión Europea
Entre las políticas laborales se encuentran las que promueven acciones con el objeto de paliar
los desequilibrios y desajustes del mercado de trabajo, distinguiéndose entre las que lo hacen
con carácter anticipador (las denominadas políticas activas) o de forma compensadora
(pasivas). Tras el Tratado de Amsterdam (1997) y la puesta en marcha de la Estrategia
Europea de Empleo (EEE), la política laboral adquiere una especial relevancia, fomentándose
la utilización de políticas activas en detrimento de las predominantes políticas pasivas.
En este trabajo se analiza la eficiencia del gasto en las diferentes acciones de política activa,
respecto a los objetivos planteados en la EEE (en cuanto a las variables de volumen y calidad
del mercado de trabajo), mediante un modelo de datos de panel, con el fin de contrastar la
preferencia demostrada por este tipo de políticas en el ámbito Europeo
Uso de la clasificación internacional DESDE-LTC como sistema de codificación y estandarización de servicios sociales y su aplicación en Atención Primaria de Salud
El sistema internacional de estandarización de servicios DESDE-LTC es una herramienta
que procura facilitar la planificación, gestión y evaluación de los servicios sociosanitarios que se
presentan en un ámbito territorial determinado. Objetivos: 1) Probar la usabilidad de DESDE–LTC
para la clasificación de servicios sociosanitarios en el ámbito de los servicios sociales y la Atención
Primaria de salud en Andalucía; 2) Desarrollar un algoritmo informático para la recolección de datos
y su codificación automática; 3) Incorporar la información a los sistemas de información geográfica
A pair of TESS planets spanning the radius valley around the nearby mid-M dwarf LTT 3780
We present the confirmation of two new planets transiting the nearby mid-M
dwarf LTT 3780 (TIC 36724087, TOI-732, , , =0.374
R, =0.401 M, d=22 pc). The two planet candidates are
identified in a single TESS sector and are validated with reconnaissance
spectroscopy, ground-based photometric follow-up, and high-resolution imaging.
With measured orbital periods of days, days and sizes
R, R, the
two planets span the radius valley in period-radius space around low mass stars
thus making the system a laboratory to test competing theories of the emergence
of the radius valley in that stellar mass regime. By combining 63 precise
radial-velocity measurements from HARPS and HARPS-N, we measure planet masses
of M and
M, which indicates that LTT 3780b has a bulk composition consistent
with being Earth-like, while LTT 3780c likely hosts an extended H/He envelope.
We show that the recovered planetary masses are consistent with predictions
from both photoevaporation and from core-powered mass loss models. The
brightness and small size of LTT 3780, along with the measured planetary
parameters, render LTT 3780b and c as accessible targets for atmospheric
characterization of planets within the same planetary system and spanning the
radius valley.Comment: Accepted to AJ. 8 figures, 6 tables. CSV file of the RV measurements
(i.e. Table 2) are included in the source cod
GJ 367b: A dense, ultrashort-period sub-Earth planet transiting a nearby red dwarf star
Ultrashort-period (USP) exoplanets have orbital periods shorter than 1 day. Precise masses and radii of USP exoplanets could provide constraints on their unknown formation and evolution processes. We present the work from Lam et al. 2021 (Science, 374, 1271) and report the detection and characterization of the USP planet GJ 367b using high-precision photometry and radial velocity observations. GJ 367b orbits a bright (V-band magnitude of 10.2), nearby, and red (M-type) dwarf star every 7.7 hours. GJ 367b has a radius of 0.718 ± 0.054 Earth-radii and a mass of 0.546 ± 0.078 Earth-masses, making it a sub-Earth planet. The corresponding bulk density is 8.106 ± 2.165 grams per cubic centimeter - close to that of iron. An interior structure model predicts that the planet has an iron core radius fraction of 86 ± 5%, similar to that of Mercury's interior