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

El desarrollo de competencias científicas a través de una experiencia de introducción de la historia de las ciencias y las técnicas en el aula

Se presenta una experiencia de formación de profesorado universitario referente a la introducción de la HCT en la enseñanza, que pretendía: -Detectar ideas previas sobre HCT y modelos de ciencia -Analizar textos histórico científicos -Reflexionar sobre diferentes visiones de la ciencia -Estudiar contribuciones de las mujeres a la ciencia -Situar los conocimientos tecnocientíficos en su contexto -Mostrar las relaciones CTS -Evaluar la utilidad de la HCT para el desarrollo de competencias científicas. Se constató la utilidad de la HCT para: -Mostrar el modelo de ciencia subyacente -Comprender las interacciones CTS y Género -Motivar al alumnado Se constató la necesidad de: -Adquirir conocimientos de HCT -Profundizar en las metodologías para la introducción de la HCT en el aula -Adaptar textos originales -Replicar experimentos -Organizar nuevas acciones formativas

La Historia de las ciencias en el desarrollo de competencias científicas

En este artículo se presenta una experiencia realizada en la asignatura Ciencias experimentales de 2º curso del grado en Educación Primaria (EP) encaminada al desarrollo de competencias científicas introduciendo la historia de las ciencias y de las técnicas (HCT). Se trata de una investigación cualitativa (Cook y Reichardt, 2005) en la que se analizan producciones presenciales y virtuales del alumnado. Se inserta en una investigación en curso sobre concepciones previas del alumnado y pretende el desarrollo de competencias, incidiendo, entre otros, en los siguientes aspectos: Concepciones sobre la naturaleza de la ciencia. Metodologías de enseñanza para producir aprendizajes. Aprendizaje colaborativo semipresencial (blended learning).This paper presents an experience developed in the Experimental Sciences subject of the second course for school teachers of Primary Education degree. This training activity was aimed at developing scientific competences introduced by the History of Science and Technology (HST). It is an educational qualitative research (Cook and Reichardt, 2005) which analyzes the presence productions and virtual exercises of the students. The experience is into a research that stem from the conceptions of students and it aims to develop scientific competences emphasizing the following aspects, to each other: The nature of science. Teaching methodologies to produce learning. Collaborative blended learning

Hands-on quantum sensing with NV- centers in diamonds

The physical properties of diamond crystals, such as color or electrical conductivity, can be controlled via impurities. In particular, when doped with nitrogen, optically active nitrogen-vacancy centers (NV), can be induced. The center is an outstanding quantum spin system that enables, under ambient conditions, optical initialization, readout, and coherent microwave control with applications in sensing and quantum information. Under optical and radio frequency excitation, the Zeeman splitting of the degenerate states allows the quantitative measurement of external magnetic fields with high sensitivity. This study provides a pedagogical introduction to the properties of the NV centers as well as a step-by-step process to develop and test a simple magnetic quantum sensor based on color centers with significant potential for the development of highly compact multisensor systemsThis research was funded by MICIN-AEI: Grants DETECTAc and EQC2018-005134-P Comunidad de Madrid: Grant TEC2SPACE-CM P2018/NMT-4291, ONR-G: G#N62909-19-1-2053 (DEFROST), MADE-MICINN: PID2019-105552RB-C44. Garantía Juvenil nº201701520868, R.B.-G. would like to thank Comunidad de Madrid for the funding through the grant 2019-T2/IND-1336

Absolute dimensions of the low-mass eclipsing binary system NSVS 10653195

Low-mass stars in eclipsing binary systems show radii larger and effective temperatures lower than theoretical stellar models predict for isolated stars with the same masses. Eclipsing binaries with low-mass components are hard to find due to their low luminosity. As a consequence, the analysis of the known low-mass eclipsing systems is key to understand this behavior. We developed a physical model of the LMDEB system NSVS 10653195 to accurately measure the masses and radii of the components. We obtained several high-resolution spectra in order to fit a spectroscopic orbit. Standardized absolute photometry was obtained to measure reliable color indices and to measure the mean Teff of the system in out-of-eclipse phases. We observed and analyzed optical VRI and infrared JK band differential light-curves which were fitted using PHOEBE. A Markov-Chain Monte Carlo (MCMC) simulation near the solution found provides robust uncertainties for the fitted parameters. NSVS 10653195 is a detached eclipsing binary composed of two similar stars with masses of M1=0.6402+/-0.0052 Msun and M2=0.6511+/-0.0052 Msun and radii of R1=0.687^{+0.017}_{-0.024} Rsun and R2=0.672^{+0.018}_{-0.022} Rsun. Spectral types were estimated to be K6V and K7V. These stars rotate in a circular orbit with an orbital inclination of i=86.22+/-0.61 degrees and a period of P=0.5607222(2) d. The distance to the system is estimated to be d=135.2^{+7.6}_{-7.9} pc, in excellent agreement with the value from Gaia. If solar metallicity were assumed, the age of the system would be older than log(age)~8 based on the Mbol-log Teff diagram. NSVS 10653195 is composed of two oversized and active K stars. While their radii is above model predictions their Teff are in better agreement with models.Comment: 14 pages, 8 figures, 12 tables. Accepted for publication in A&A. Tables 1, 2, 3 and 7 are only available in electronic form at the CDS (Strasbourg

Safety of statins when response is carefully monitored: a study of 336 heart recipients

[Abstract] Background. Statins are used as first-line drugs against hypercholesterolemia after heart transplantation. Randomized clinical trials have shown that they reduce cholesterol levels, and the incidence of rejection and coronary vasculopathy. Adverse effects have been related to the use of certain statins, high statin dosages, comorbidities, and coadministration with cyclosporine. However, estimation of the risk of adverse effects for a given patient is difficult. The aims of this study were to determine the incidence of various kinds of adverse effect of statins; to evaluate certain potential risk factors; and to assess the efficacy of early response to signs of adverse effects. Methods. Between April 1991 and December 2003, we retrospectively evaluated 336 heart transplant patients (including 55 women) with regard to the occurrence of possible adverse effects of statins (rhabdomyolysis, myalgia, hepatotoxicity, high CK without muscle symptoms, and others). Resolution on reduction of dosage or discontinuance and/or change of statin were deemed to constitute confirmation of cause. Relations were sought between adverse effects and age, sex, immunosuppressive therapy, kidney failure, body mass index (BMI), arterial hypertension, and diabetes mellitus. Results. Possible adverse events of statins were suffered by 60 patients, all of them men. The causal role of statins was confirmed in 41 (12.2% of all 336): hepatotoxicity was suffered by 13, high CK without muscle ache or weakness by 18, rhabdomyolysis by 5, myalgia by 3, and other effects by 2. The incidence of confirmed statin-related complications was higher among patients with BMI >29 kg/m2 than among those with lower BMI (P = .055). None of the patients with confirmed statin-related complications needed dialysis, none died, and permanent suspension of statin treatment was only necessary in 13 cases (3.9% of the 336). Conclusions. Some 10% to 20% of HT patients appear to suffer adverse side effects of initial statin therapy. However, early detection of such effects through diligent clinical and analytical monitoring allows the therapy to be modified in time to minimize the appearance of severe complications. In only a minority of cases permanent suspension of statin therapy is necessary

Long-term results of heart transplant in recipients older and younger than 65 years: a comparative study of mortality, rejections, and neoplasia in a cohort of 445 patients

[Resumen] Background. Whether being older than 65 years should be considered an absolute counterindication to heart transplant (HT), as it is in some centers, is controversial. In our centre, patients older than 65 years are accepted for HT if they satisfy stringent conditions. The aim of this study was to examine whether heart recipients older than 65 years have a greater risk of rejection, neoplasia, or mortality than younger ones. Methods. We studied 445 patients who underwent HT between April 1991 and December 2003, 42 of whom were older than 65 years and 403 who were 65 years or younger. The parameters evaluated were the cumulative incidences of neoplasias and rejections (ISHLT grade ≥ 3A), and the survival rates 1 month, 1 year, and 5 years post-HT. Results. The two groups had similar percentages of patients with at least one rejection episode (≤65 years 56.9%, >65 years 51.3%; P > .05), and although there were proportionally almost twice as many tumors in the older group (14.2%) as in the younger (7.9%), this difference was not statistically significant either. Nor were there any significant differences in survival, the 1-month, 1-year, and 5-year rates being 87.8%, 82.1%, and 68.8%, respectively, in the younger group and 85.7%, 78.6%, and 73.4%, respectively, in the older. Conclusions. Among carefully selected patients aged more than 65 years, HT can be performed without incurring greater risk of rejection, malignancy, or death than is found among recipients younger than 65 years