32 research outputs found

    PASTIS: Bayesian extrasolar planet validation. I. General framework, models, and performance

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    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

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    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

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    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

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    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

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    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

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    We present the confirmation of two new planets transiting the nearby mid-M dwarf LTT 3780 (TIC 36724087, TOI-732, V=13.07V=13.07, Ks=8.204K_s=8.204, RsR_s=0.374 R_{\odot}, MsM_s=0.401 M_{\odot}, 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 Pb=0.77P_b=0.77 days, Pc=12.25P_c=12.25 days and sizes rp,b=1.33±0.07r_{p,b}=1.33\pm 0.07 R_{\oplus}, rp,c=2.30±0.16r_{p,c}=2.30\pm 0.16 R_{\oplus}, 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 mp,b=2.620.46+0.48m_{p,b}=2.62^{+0.48}_{-0.46} M_{\oplus} and mp,c=8.61.3+1.6m_{p,c}=8.6^{+1.6}_{-1.3} M_{\oplus}, 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

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    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
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