The BaSTI Stellar Evolution Database: models for extremely metal-poor and super-metal-rich stellar populations

We present an extension of the BaSTI stellar evolution database to extremely metal poor (${\rm Z=10^{-5}}$) and super-metal-rich (Z=0.05) metallicities, with both scaled-solar and $\alpha$-enhanced ([$\alpha$/Fe]=0.4) heavy element distributions. These new tracks (from the pre-main sequence to the early-asymptotic giant branch phase), horizontal branch models and isochrones, will enable the use of the BaSTI database to study, i.e., the most metal poor populations found in Local Group faint dwarf galaxies, and the metal rich component of the Galactic bulge. An overview of several fundamental predictions of stellar evolution over the full metallicity range of BaSTI is presented, together with comparisons with literature calculations at ${\rm Z=10^{-5}}$ and Z=0.05.Comment: 11 pages, 15 Figures, A&A in pres

The Star Formation History in a SMC field: IAC-star/IAC-pop at work

We present a progress report of a project to study the quantitative star formation history (SFH) in different parts of the Small Magellanic Cloud (SMC). We use the information in [(B-R), R] color-magnitude diagrams (CMDs), which reach down to the oldest main-sequence turnoffs and allow us to retrieve the SFH in detail. We show the first results of the SFH in a SMC field located in the Southern direction (at $\thicksim$1 kpc from the SMC center). This field is particularly interesting because in spite of being located in a place in which the HI column density is very low, it still presents a recent enhancement of star formation.Comment: Poster presented at: Stellar Populations as Building Blocks of Galaxies, Proceedings IAU Symposium No. 241, 200

Spatial dependence of the Star Formation History in the Central Regions of the Fornax Dwarf Spheroidal Galaxy

We present the Star Formation History (SFH) and the age-metallicity relation (AMR) in three fields of the Fornax dwarf spheroidal galaxy. They sample a region spanning from the centre of the galaxy to beyond one core radius, which allows studying galactocentric gradients. In all the cases, we found stars as old as 12 Gyr, together with intermediate-age and young stellar populations. The last star formation events, as young as 1 Gyr old, are mainly located in the central region, which may indicate that the gas reservoir in the outer parts of the galaxy would have been exhausted earlier than in the centre or removed by tidal interactions. The AMR is smoothly increasing in the three analyzed regions and similar to each other, indicating that no significant metallicity gradient is apparent within and around the core radius of Fornax. No significant traces of global UV-reionization or local SNe feedback are appreciated in the early SFH of Fornax. Our study is based on FORS1@VLT photometry as deep as I~24.5 and the IAC-star/IAC-pop/MinnIAC suite of codes for the determination of the SFH in resolved stellar populations.Comment: 13 pages, 8 figures, 4 table

Applications of Independence Statistics to Goodness-Of-Fit, Multivariate Change Point Estimation and Clustering of Variables

Independence statistics try to evaluate the statistical dependence between two random vectors of general dimension and type. Independence statistics do not assume a specific form of dependence, but they are sensitive to all forms of departures from independence. The current manuscript seeks to extend the use of independence statistics to three settings. In the first part of the dissertation, we developed a goodness-of-fit test for smoothing spline ANOVA models, which are a nonparametric regression methodology with the useful property that the contribution of the covariates can be decomposed in a ANOVA fashion. The proposed method derives estimated residuals from the model. Then, statistical dependence is evaluated between the estimated residuals and the covariates using independence statistics. If no dependence exists, the model fits the data well. Application of the method is demonstrated with a neonatal mental development data analysis. In the second part, we develop a method for the change point problem where two sets of random vectors are observed sequentially over a dimension, but at some unknown point, the relationship between these two vectors changes. We propose a methodology to estimate the unknown change point without assuming a model. This is accomplished by assessing, with an independence statistic, the strength of the association before and after possible change points. A test for the hypothesis of existence of the change point is developed. We demonstrate its use with blood glucose and physical activity measurements on an individual with type 1 diabetes. In the third part, we develop a method for hierarchical clustering of variables while controlling for type I error rate, which is not done in common clustering methods. We accomplish this by turning the decision of whether to join two clusters into a hypothesis testing problem. The strength of our method is shown by clustering genes from single cell data coming from different tumors.Doctor of Philosoph

Inteligencia emocional y estrés académico en internos rotativos de enfermería que cursan su rotación en un hospital de Ecuador, 2021

El desarrollo de esta investigación se realizó con el objetivo de determinar la influencia de la inteligencia emocional en el estrés académico de los internos rotativos de enfermería que cursan su rotación en un hospital de Ecuador, 2021. Dentro del diseño metodológico se efectuó con el enfoque cuantitativo, de tipo aplicativo, no probabilístico, con diseño de no experimental con un estudio transversal. La población estuvo conformada por un total de 60 estudiantes que cursan el año del internado rotativo realizando sus pasantías en un hospital de Ecuador, la técnica que se utilizó fue la encuesta online mediante un link enviado a cada participante, en la cual se trascribió los cuestionarios de preguntas en la aplicación de Google Forms, los dos instrumentos fueron validados y certificados en estudios previos. Para su confiabilidad se realizó una prueba piloto en la cual se dio uso al Coeficiente Alfa de Cronbach 0,82 para el cuestionario de estrés académico. El estadístico que se empleó en este estudio fue Rho de Spearman con un valor de 0,80 la cual indica una correlación aceptable entre las variables Inteligencia emocional y estrés Académico, es decir a mejor inteligencia emocional menor estrés académico en los internos de enfermería de un hospital de Ecuador

Detection of satellite remnants in the Galactic Halo with Gaia III. Detection limits for Ultra Faint Dwarf Galaxies

We present a method to identify Ultra Faint Dwarf Galaxy (UFDG) candidates in the halo of the Milky Way using the future Gaia catalogue and we explore its detection limits and completeness. The method is based on the Wavelet Transform and searches for over-densities in the combined space of sky coordinates and proper motions, using kinematics in the search for the first time. We test the method with a Gaia mock catalogue that has the Gaia Universe Model Snapshot (GUMS) as a background, and use a library of around 30 000 UFDGs simulated as Plummer spheres with a single stellar population. For the UFDGs we use a wide range of structural and orbital parameters that go beyond the range spanned by real systems, where some UFDGs may remain undetected. We characterize the detection limits as function of the number of observable stars by Gaia in the UFDGs with respect to that of the background and their apparent sizes in the sky and proper motion planes. We find that the addition of proper motions in the search improves considerably the detections compared to a photometric survey at the same magnitude limit. Our experiments suggest that Gaia will be able to detect UFDGs that are similar to some of the known UFDGs even if the limit of Gaia is around 2 magnitudes brighter than that of SDSS, with the advantage of having a full-sky catalogue. We also see that Gaia could even find some UFDGs that have lower surface brightness than the SDSS limit.Comment: Accepted for publication in MNRA