19 research outputs found
Gaia FGK Benchmark Stars: fundamental Teff and log g of the third version
Context. Large spectroscopic surveys devoted to the study of the Milky Way,
including Gaia, use automated pipelines to massively determine the atmospheric
parameters of millions of stars. The Gaia FGK Benchmark Stars are reference
stars with Teff and log g derived through fundamental relations, independently
of spectroscopy, to be used as anchors for the parameter scale. The first and
second versions of the sample have been extensively used for that purpose, and
more generally to help constrain stellar models. Aims. We provide the third
version of the Gaia FGK Benchmark Stars, an extended set intended to improve
the calibration of spectroscopic surveys, and their interconnection. Methods.
We have compiled about 200 candidates which have precise measurements of
angular diameters and parallaxes. We determined their bolometric fluxes by
fitting their spectral energy distribution. Masses were determined using two
sets of stellar evolution models. In a companion paper we describe the
determination of metallicities and detailed abundances. Results. We provide a
new set of 192 Gaia FGK Benchmark Stars with their fundamental Teff and logg,
and with uncertainties lower than 2% for most stars. Compared to the previous
versions, the homogeneity and accuracy of the fundamental parameters are
significantly improved thanks to the high quality of the Gaia data reflecting
on distances and bolometric fluxes.Comment: accepted in A&
HD 213885b: a transiting 1-d-period super-Earth with an Earth-like composition around a bright (V = 7.9) star unveiled by TESS
We report the discovery of the 1.008-d, ultrashort period (USP) super-Earth HD 213885b (TOI-141b) orbiting the bright (V = 7.9) star HD 213885 (TOI-141, TIC 403224672), detected using photometry from the recently launched TESS mission. Using FEROS, HARPS, and CORALIE radial velocities, we measure a precise mass of 8.8 ± 0.6 M⊕ for this 1.74 ± 0.05 R⊕ exoplanet, which provides enough information to constrain its bulk composition – similar to Earth’s but enriched in iron. The radius, mass, and stellar irradiation of HD 213885b are, given our data, very similar to 55 Cancri e, making this exoplanet a good target to perform comparative exoplanetology of short period, highly irradiated super-Earths. Our precise radial velocities reveal an additional 4.78-d signal which we interpret as arising from a second, non-transiting planet in the system, HD 213885c, whose minimum mass of 19.9 ± 1.4 M⊕ makes it consistent with being a Neptune-mass exoplanet. The HD 213885 system is very interesting from the perspective of future atmospheric characterization, being the second brightest star to host an USP transiting super-Earth (with the brightest star being, in fact, 55 Cancri). Prospects for characterization with present and future observatories are discussed
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Afectación del sistema cardiovascular en la infección por SARS-CoV-2
Introducción: la COVID-19 es una enfermedad emergente con incidencia global, que exhibe mayor número de complicaciones en pacientes con comorbilidades, principalmente en aquellos con antecedentes de enfermedades cardiovasculares.
Objetivo: describir las implicaciones de la COVID-19 en el sistema cardiovascular.
Método: Se realizó una revisión de la literatura en las bases de datos MEDLINE, SciELO, JAMA y Elsevier, recuperándose 35 artículos, los cuales se tomaron de base para la presente revisión. Se empleó la combinación de términos mediante fórmulas de búsqueda para recuperar los artículos.
Desarrollo: la COVID-19 puede ser variable en correspondencia con la forma de presentación y síntomas acompañantes, así como la respuesta inmunitaria del receptor. El SARS-CoV-2 se une a las células a través de la proteína estructural viral de espiga que se une al receptor de la enzima convertidora de angiotensina 2 a partir de receptores virales; por ello, los pacientes hipertensos o con otras afecciones cardiovasculares tienen un mayor riesgo de desarrollar formas severas de COVID-19. Dentro de las afectaciones cardiovasculares asociados a la infección por un coronavirus destacan la miocarditis, arritmias, infarto agudo de miocardio e insuficiencia cardíaca.
Conclusiones: Las principales implicaciones cardiovasculares en los pacientes con COVID-19 son arritmia, enfermedad tromboembólica, miocarditis, insuficiencia cardiaca de inicio agudo e infarto de miocardio, las cuales condicionan un cuadro más grave de la enfermedad. La respuesta inflamatoria, los cambios hemodinámicos secundarios al proceso viral, así como la hipoxemia, constituyen mecanismos de repercusión negativa sobre la salud cardiovascular, llevando al desarrollo de lesión cardiaca aguda
Gaia FGK Benchmark Stars: fundamental Teff and log g of the third version
Context. Large spectroscopic surveys devoted to the study of the Milky Way, including Gaia, use automated pipelines to massively determine the atmospheric parameters of millions of stars. The Gaia FGK Benchmark Stars are reference stars with Teff and log g derived through fundamental relations, independently of spectroscopy, to be used as anchors for the parameter scale. The first and second versions of the sample have been extensively used for that purpose, and more generally to help constrain stellar models. Aims. We provide the third version of the Gaia FGK Benchmark Stars, an extended set intended to improve the calibration of spectroscopic surveys, and their interconnection. Methods. We have compiled about 200 candidates which have precise measurements of angular diameters and parallaxes. We determined their bolometric fluxes by fitting their spectral energy distribution. Masses were determined using two sets of stellar evolution models. In a companion paper we describe the determination of metallicities and detailed abundances. Results. We provide a new set of 192 Gaia FGK Benchmark Stars with their fundamental Teff and logg, and with uncertainties lower than 2% for most stars. Compared to the previous versions, the homogeneity and accuracy of the fundamental parameters are significantly improved thanks to the high quality of the Gaia data reflecting on distances and bolometric fluxes
The third version of the Gaia FGK Benchmark Stars
International audienceThe Gaia FGK Benchmark Stars (GBS) are reference stars carefully selected for the calibration and the validation of atmospheric parameters massively determined from large-scale spectroscopic surveys. Their Teff and logg are determined independently of spectroscopy, through the fundamental relations based on angular diameters, bolometric fluxes, parallaxes and masses. An initial version of the GBS comprising 34 stars was presented by \cite{hei15}. We now introduce the third version, GBS V3, which comprises ∼200 stars
The third version of the Gaia FGK Benchmark Stars
The Gaia FGK Benchmark Stars (GBS) are reference stars carefully selected for the calibration and the validation of atmospheric parameters massively determined from large-scale spectroscopic surveys. Their Teff and logg are determined independently of spectroscopy, through the fundamental relations based on angular diameters, bolometric fluxes, parallaxes and masses. An initial version of the GBS comprising 34 stars was presented by \cite{hei15}. We now introduce the third version, GBS V3, which comprises ∼200 stars