Bisectors of the HARPS Cross-Correlation-Function. The dependence on stellar atmospheric parameters

Bisectors of the HARPS cross-correlation function (CCF) can discern between planetary radial-velocity (RV) signals and spurious RV signals from stellar magnetic activity variations. However, little is known about the effects of the stellar atmosphere on CCF bisectors or how these effects vary with spectral type and luminosity class. Here we investigate the variations in the shapes of HARPS CCF bisectors across the HR diagram in order to relate these to the basic stellar parameters, surface gravity and temperature. We use archive spectra of 67 well studied stars observed with HARPS and extract mean CCF bisectors. We derive previously defined bisector measures (BIS, v_bot, c_b) and we define and derive a new measure called the CCF Bisector Span (CBS) from the minimum radius of curvature on direct fits to the CCF bisector. We show that the bisector measures correlate differently, and non-linearly with log g and T_eff. The resulting correlations allow for the estimation of log g and T_eff from the bisector measures. We compare our results with 3D stellar atmosphere models and show that we can reproduce the shape of the CCF bisector for the Sun.Comment: 13 pages, 20 figures. Accepted by A&

Proposal for mathematical learning in the Infantil Education classroom based on a story and the use of ICT

Las características propias de nuestra sociedad, altamente tecnificada, traen consigo la necesidad de que los ciudadanos sean capaces de responder ante diferentes situaciones de su día a día utilizando conocimientos de tipo matemático, desde edades tempranas. El cambio forzoso a una educación on-line dado durante el año 2020 y provocado por el virus SARS-Cov2 ha reflejado esta necesidad, que puede verse compensada con un adecuado uso de las Tecnologías de la Información y la Comunicación (TIC) en los procesos de enseñanza-aprendizaje por parte del profesorado y del alumnado. En el siguiente artículo se pretende ofrecer una propuesta para trabajar en Educación Infantil contenidos matemáticos a partir del uso de las TIC y teniendo como base la lectura del cuento de Jérôme Ruillier, Por cuatro esquinitas de nada, desde un entorno de trabajo on-line.  The characteristics of our society, highly technical, bring with them the need for citizens to be able to respond to different situations of their day to day using mathematical knowledge, from an early age. The forced change to an online education given during 2020 and caused by the SARS-Cov2 virus has reflected this need, which can be compensated with an adequate use of Information and Communication Technologies (ICT) in the processes teaching-learning by teachers and students. The following article aims to offer a proposal to work in Infantil Education with mathematical content based on the use of ICT and based on the reading of the story by Jérôme Ruillier, Por cuatro esquinitas de nada, from an online work environment

The SOPHIE search for northern extrasolar planets. V. Follow-up of ELODIE candidates: Jupiter-analogs around Sun-like stars

We present radial-velocity measurements obtained in a programs underway to search for extrasolar planets with the spectrograph SOPHIE at the 1.93-m telescope of the Haute-Provence Observatory. Targets were selected from catalogs observed with ELODIE, mounted previously at the telescope, in order to detect long-period planets with an extended database close to 15 years. Two new Jupiter-analog candidates are reported to orbit the bright stars HD150706 and HD222155 in 16.1 and 10.9 yr at 6.7 (+4.0,-1.4) and 5.1(+0.6,-0.7) AU and to have minimum masses of 2.71 (+1.44,-0.66) and 1.90 (+0.67,-0.53) M_Jup, respectively. Using the measurements from ELODIE and SOPHIE, we refine the parameters of the long-period planets HD154345b and HD89307b, and publish the first reliable orbit for HD24040b. This last companion has a minimum mass of 4.01 +/- 0.49 M_Jup orbiting its star in 10.0 yr at 4.92 +/- 0.38 AU. Moreover, the data provide evidence of a third bound object in the HD24040 system. With a surrounding dust debris disk, HD150706 is an active G0 dwarf for which we partially corrected the effect of the stellar spot on the SOPHIE radial-velocities. HD222155 is an inactive G2V star. On the basis of the previous findings of Lovis and collaborators and since no significant correlation between the radial-velocity variations and the activity index are found in the SOPHIE data, these variations are not expected to be only due to stellar magnetic cycles. Finally, we discuss the main properties of this new population of long-period Jupiter-mass planets, which for the moment, consists of fewer than 20 candidates. These stars are preferential targets either for direct-imaging or astrometry follow-up to constrain the system parameters and for higher precision radial-velocity to search for lower mass planets, aiming to find a Solar System twin.Comment: accepted for publication in Astronomy & Astrophysic

La formación de equipos cooperativos: una revisión sistemática

      Cooperative learning is an active methodology where students, in small groups, carry out activities in a coordinated manner to achieve a common learning objective. Over the years it has been proven that it is a methodology that increases students\u27 performance, increasing their self-esteem and improving their social skills. One of the key elements to achieve the best results is the implementation of the methodology, which includes the formation of the teams. Through a systematic review, following the PRISMA statement, the latest advances made in this regard are analyzed. The importance of team formation is shown, taking into account the students\u27 previous academic performance, gender, race, ethnicity, interest, and social and attitudinal skills, and the instruments that have been evaluated as support for the teacher are presented.El aprendizaje cooperativo es una metodología activa donde los alumnos, en pequeños grupos, realizan actividades de forma coordinada para alcanzar un objetivo de aprendizaje común. A lo largo de los años se ha demostrado que es una metodología que incrementa el rendimiento de los alumnos, aumentando su autoestima y mejorando sus habilidades sociales. Uno de los elementos clave para alcanzar los mejores resultados es la implementación de la metodología donde se incluye la formación de los equipos. A través de una revisión sistemática, siguiendo la declaración PRISMA, se analizan los últimos avances realizados al respecto. Se muestra la importancia de la formación de los equipos donde se tiene en cuenta el rendimiento académico previo de los estudiantes, género, raza, etnia, interés y habilidades sociales y actitudinales y se presentan los instrumentos que se han evaluado como apoyo para el docente

Accurate fundamental parameters for 23 bright solar-type stars

We combine results from interferometry, asteroseismology and spectroscopy to determine accurate fundamental parameters of 23 bright solar-type stars, from spectral type F5 to K2 and luminosity classes III to V. For some stars we can use direct techniques to determine the mass, radius, luminosity and effective temperature, and we compare with indirect methods that rely on photometric calibrations or spectroscopic analyses. We use the asteroseismic information available in the literature to infer an indirect mass with an accuracy of 4-15 percent. From indirect methods we determine luminosity and radius to 3 percent. For Teff we find a slight offset of -40+-20 K between the spectroscopic method and the direct method, meaning the spectroscopic temperatures are too high. From the spectroscopic analysis we determine the detailed chemical composition for 13 elements, including Li, C and O. We find no significant offset between the spectroscopic surface gravity and the value from combining asteroseismology with radius estimates. From the spectroscopy we also determine vsini and we present a new calibration of macro- and microturbulence. From the comparison between the results from the direct and spectroscopic methods we claim that we can determine Teff, log g, and [Fe/H] with absolute accuracies of 80 K, 0.08 dex, and 0.07 dex. The indirect methods are important to obtain reliable estimates of the fundamental parameters of relatively faint stars when interferometry cannot be used. Our study is the first to compare direct and indirect methods for a large sample of stars, and we conclude that indirect methods are valid, although slight corrections may be needed.Comment: Accepted by MNRAS. Abstract abridge

DNA extraction as a didactic strategy to learn about the cell in primary and secondary education

Today’s society is widely influenced by the great scientific and technological advances that have been developed since the last century. This implies that citizens face in their daily problematic situations that require the implementation of scientific skills, establishing the importance of the development of scientific literacy, which allows reflection, reasoning and the establishment of connections to solve them satisfactorily. In this sense, practical work is an optimal tool in the classroom, since they place students at the center of the teaching-learning process, seeking solutions to facts that are part of their daily lives through observation and manipulation, transforming them into school scientific facts and thus acquiring new knowledge. Therefore, this work analyzes a practical experience: DNA extraction. To this end, the structure of DNA is presented, the steps that are usually carried out in any process of extraction of this macromolecule are analyzed and a proposal is designed for Primary Education and another for Compulsory Secondary Education in which students extract DNA from everyday material and acquire knowledge about its structure following the scientific method. As results, both proposals have been validated through an expert judgment, highlighting that they are innovative and attractive to students. In conclusion, it is recommended to implement the proposals as well as to take into account the time needed for their development and the importance of the number of students present in the classroom.La sociedad actual está ampliamente influenciada por los grandes adelantos científicos y tecnológicos que se han desarrollado desde el siglo pasado. Esto implica que la ciudadanía se enfrenta diariamente a situaciones problemáticas que requieren la puesta en marcha de competencias científicas, estableciendo la importancia del desarrollo de la alfabetización científica, que permite la reflexión, el razonamiento y el establecimiento de conexiones para resolverlas de manera satisfactoria. En este sentido, los trabajos de tipo práctico suponen una herramienta óptima en las aulas, puesto que sitúan al alumnado en el centro del proceso de enseñanza-aprendizaje, buscando soluciones a hechos que forman parte de su vida cotidiana mediante la observación y la manipulación, transformándolos en hechos científicos escolares y adquiriendo así nuevos conocimientos. Por todo ello, en este trabajo se analiza una experiencia práctica: la extracción de ADN. A tal efecto, se presenta la estructura de ADN, se analizan los pasos que suelen llevarse a cabo en cualquier proceso de extracción de esta macromolécula y se diseña una propuesta para Educación Primaria y otra para Educación Secundaria Obligatoria en las que los estudiantes extraen ADN de material cotidiano y adquieren conocimientos sobre su estructura siguiendo el método científico. Como resultados, ambas propuestas han sido validadas a través de un juicio de expertos destacando que son innovadoras y atractivas para los alumnos. Como conclusión se recomienda implementar las propuestas, así como tener en cuenta el tiempo necesario para su desarrollo y la importancia del número de alumnos presentes en el aula

Amyloidogenic propensity of a natural variant of human apolipoprotein A-I: Stability and interaction with ligands

A number of naturally occurring mutations of human apolipoprotein A-I (apoA-I) have been associated with hereditary amyloidoses. The molecular mechanisms involved in amyloid-associated pathology remain largely unknown. Here we examined the effects of the Arg173Pro point mutation in apoA-I on the structure, stability, and aggregation propensity, as well as on the ability to bind to putative ligands. Our results indicate that the mutation induces a drastic loss of stability, and a lower efficiency to bind to phospholipid vesicles at physiological pH, which could determine the observed higher tendency to aggregate as pro-amyloidogenic complexes. Incubation under acidic conditions does not seem to induce significant desestabilization or aggregation tendency, neither does it contribute to the binding of the mutant to sodium dodecyl sulfate. While the binding to this detergent is higher for the mutant as compared to wt apoA-I, the interaction of the Arg173Pro variant with heparin depends on pH, being lower at pH 5.0 and higher than wt under physiological pH conditions. We suggest that binding to ligands as heparin or other glycosaminoglycans could be key events tuning the fine details of the interaction of apoA-I variants with the micro-environment, and probably eliciting the toxicity of these variants in hereditary amyloidoses.Facultad de Ciencias MédicasInstituto de Investigaciones Bioquímicas de La PlataInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Amyloidogenic propensity of a natural variant of human apolipoprotein A-I: Stability and interaction with ligands

A number of naturally occurring mutations of human apolipoprotein A-I (apoA-I) have been associated with hereditary amyloidoses. The molecular mechanisms involved in amyloid-associated pathology remain largely unknown. Here we examined the effects of the Arg173Pro point mutation in apoA-I on the structure, stability, and aggregation propensity, as well as on the ability to bind to putative ligands. Our results indicate that the mutation induces a drastic loss of stability, and a lower efficiency to bind to phospholipid vesicles at physiological pH, which could determine the observed higher tendency to aggregate as pro-amyloidogenic complexes. Incubation under acidic conditions does not seem to induce significant desestabilization or aggregation tendency, neither does it contribute to the binding of the mutant to sodium dodecyl sulfate. While the binding to this detergent is higher for the mutant as compared to wt apoA-I, the interaction of the Arg173Pro variant with heparin depends on pH, being lower at pH 5.0 and higher than wt under physiological pH conditions. We suggest that binding to ligands as heparin or other glycosaminoglycans could be key events tuning the fine details of the interaction of apoA-I variants with the micro-environment, and probably eliciting the toxicity of these variants in hereditary amyloidoses.Facultad de Ciencias MédicasInstituto de Investigaciones Bioquímicas de La PlataInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

N-terminal mutants of human apolipoprotein A-I : Structural perturbations associated to protein misfolding

Since the early description of different human apolipoprotein A-I variants associated to amyloidosis, the reason that determines its deposition inducing organ failure has been under research. To shed light into the events associated to protein aggregation, we studied the effect of the structural perturbations induced by the replacement of a Leucine in position 60 by an Arginine as it occurs in the natural amyloidogenic variant (L60R). Circular dichroism, intrinsic fluorescence measurements and assays of binding to ligands indicate that L60R is more unstable, more sensitive to proteolysis and interacts with sodium dodecyl sulfate (a model of negative lipids) more than the protein with the native sequence and other natural variant tested, involving a replacement of a Trytophan by and Arginine in the amino acid 50 (W50R). In addition, the small structural rearrangement observed under physiological pH leads to the release of tumor necrosis factor α and interleukin-lβ from a model of macrophages. Our results strongly suggest that the chronic disease may be a consequence of the loss in the native conformation which alters the equilibrium among native and cytotoxic proteins conformation.Instituto de Investigaciones Bioquímicas de La PlataFacultad de Ciencias MédicasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Microsoft Teams: una plataforma digital y sus múltiples aplicaciones para el desarrollo de nuevas metodologías docentes y el fomento una enseñanza cooperativa y participativa

Memoria ID2022-127 Ayudas de la Universidad de Salamanca para la innovación docente, curso 2022-2023