Machine learning techniques to select Be star candidates. An application in the OGLE-IV Gaia south ecliptic pole field

Statistical pattern recognition methods have provided competitive solutions for variable star classification at a relatively low computational cost. In order to perform supervised classification, a set of features is proposed and used to train an automatic classification system. Quantities related to the magnitude density of the light curves and their Fourier coefficients have been chosen as features in previous studies. However, some of these features are not robust to the presence of outliers and the calculation of Fourier coefficients is computationally expensive for large data sets. We propose and evaluate the performance of a new robust set of features using supervised classifiers in order to look for new Be star candidates in the OGLE-IV Gaia south ecliptic pole field. We calculated the proposed set of features on six types of variable stars and on a set of Be star candidates reported in the literature. We evaluated the performance of these features using classification trees and random forests along with K-nearest neighbours, support vector machines, and gradient boosted trees methods. We tuned the classifiers with a 10-fold cross-validation and grid search. We validated the performance of the best classifier on a set of OGLE-IV light curves and applied this to find new Be star candidates. The random forest classifier outperformed the others. By using the random forest classifier and colour criteria we found 50 Be star candidates in the direction of the Gaia south ecliptic pole field, four of which have infrared colours consistent with Herbig Ae/Be stars. Supervised methods are very useful in order to obtain preliminary samples of variable stars extracted from large databases. As usual, the stars classified as Be stars candidates must be checked for the colours and spectroscopic characteristics expected for them

A revised distance to IRAS 16293−-2422 from VLBA astrometry of associated water masers

IRAS 16293-2422 is a very well studied young stellar system seen in projection towards the L1689N cloud in the Ophiuchus complex. However, its distance is still uncertain with a range of values from 120 pc to 180 pc. Our goal is to measure the trigonometric parallax of this young star by means of H$_2$O maser emission. We use archival data from 15 epochs of VLBA observations of the 22.2 GHz water maser line. By modeling the displacement on the sky of the H$_2$O maser spots, we derived a trigonometric parallax of $7.1\pm1.3$ mas, corresponding to a distance of $141_{-21}^{+30}$ pc. This new distance is in good agreement with recent values obtained for other magnetically active young stars in the L1689 cloud. We relate the kinematics of these masers with the outflows and the recent ejections powered by source A in the system.Comment: 14 pages, 6 tables, 8 figures. Accepted to be published in Astronomy \& Astrophysic

Plan PrEFiNE: Plan estratégico para la enfermedad de Fabry en Nefrología

Background Renal failure is one of the main causes of death in patients with Fabry disease (FD). Due to the low prevalence of FD, delayed diagnosis and misdiagnosis, often the correct diagnosis is made when organ damage is already present. Early recognition of the disease would allow the prevention of severe complications and the premature death of patients with FD. Objective We present here the PrEFiNE project, which includes a wide spectrum of activities with the aim of improve knowledge and diagnosis of FD. The project is sponsored by Shire Iberia (http://shireiberica.com/) Methods From January 2016 to the end of 2017 several activities will be carried out, starting with a survey to evaluate current FD knowledge among nephrologists; in addition some studies to assess prevalence of this disease will be performed. One study will include patients receiving dialysis, another study will cover kidney transplant patients, and a pilot study in chronic kidney disease in stage 3-5 predialysis. Also planned is a pharmacoeconomic study to focus on burden of FD. At the same time medical education activities will be conducted both on line and on site. Plan for dissemination will include medical publications and diffusion to media. PrEFiNE Project will finish with the publication of a compilation book on FD in Nephrology including all planned activities and proposing recommendations based on results and detected unmet needs. PrEfiNE Plan will be coordinated by severa scientific committees, one at national level and 10 other regionals comittees, tha will be responsible to ensure the maximum scientific quality of proposed activities. An advisory board will supervise the project. Discussion PrEfiNE project will evaluate an action plan focused on improving FD knowledge to make necessary recommendations for an early recognition of the disease. In addition will generate a plan to improve previously undetected needs.Justificación: La enfermedad renal es una de las principales causas de muerte entre los pacientes con enfermedad de Fabry (EF). Al tratarse de una enfermedad de baja prevalencia, se realizan con frecuencia diagnósticos erróneos y retrasados, que a menudo se dan cuando ya se ha producido dan˜ o orgánico. El reconocimiento temprano de la enfermedad permitiría evitar las complicaciones graves y la muerte prematura en estos pacientes. Objetivo: Presentamos en este artículo un resumen del plan PrEFiNE, que incluye un abanico amplio de actividades con el objetivo de mejorar el conocimiento y reconocimiento de la EF entre los nefrólogos. Este proyecto está patrocinado por Shire Ibérica (http://shireiberica.com/). Métodos: Desde enero de 2016 y hasta finales del 2017 se iniciarán distintas actividades, comenzando por una evaluación del grado de conocimiento que existe actualmente sobre la EF. Se incluyen 3 estudios de prevalencia de la EF, que abarcan el espectro de los pacientes con enfermedad renal crónica (pacientes en diálisis, pacientes trasplantados renales y un estudio piloto en pacientes con enfermedad renal crónica en estadio 3–5 prediálisis) y un estudio farmacoeconómico, centrado en el impacto de la carga de la enfermedad. Parale- lamente, se realizarán actividades formativas tanto presenciales como on line, y un amplio plan de comunicación mediante publicaciones y difusión a medios. El proyecto culminará con la publicación de un libro blanco de la EF en Nefrología, que recoja el resultado de todas las actividades y que proponga recomendaciones en respuesta a los resultados y a las necesidades detectadas. El plan PrEFiNE estará coordinado por distintos comités científicos, uno nacional y 10 regionales que garantizarán el desarrollo de las acciones con el máximo rigor científico y será supervisado por un comité asesor. Discusión: El plan PrEFiNE nos permitirá evaluar la utilidad de un proyecto dirigido a mejorar el conocimiento de una enfermedad minoritaria como la EF a nivel nacional, y a partir del cual se podrán establecer las recomendaciones necesarias para mejorar su reconocimiento, además de planes enfocados a mejorar las necesidades no cubiertas detectadas durante su desarroll

Is the Fluorescence Quantum Yield of Tryptophan Independent of Excitation Wavelength?

Tryptophan is a fluorescent amino acid that is commonly used as a probe in protein structure-dynamics studies. It is also widely used as a convenient standard for measurements of fluorescence quantum yields of organic and bioorganic molecules. Literature values of the fluorescence quantum yield range from 0.13 to 0.15 upon excitation of tryptophan at 270 nm in aqueous solution. Even though the fluorescence quantum yield of tryptophan is known with a high degree of accuracy upon excitation at 270 nm (i.e., ca. ± 0.02), this value is being used indiscriminately in the literature for the determination of the fluorescence quantum yield of molecules at other excitation wavelengths. In those studies, the assumption has been made that the magnitude of the fluorescence quantum yield of tryptophan does not change with excitation wavelength. This assumption is based on the so-called Kasha’s rule, which states that fluorescence emission occurs in appreciable yield only from the lowest excited singlet state of an organic molecule. Consequently, the fluorescence quantum yield is typically independent of the excitation wavelength used. However, many molecules are known to not obey the Kasha’s rule. Therefore, in this study, we examine the hypothesis that the fluorescence quantum yield of tryptophan does not depend on the excitation wavelength used. We also investigate if the fluorescence quantum yield of tryptophan varies when the salt concentration of the phosphate buffer solution at a physiological pH of 7.4 is varied. The results demonstrate that the fluorescence quantum yield of tryptophan depends on excitation wavelength. It is, however, independent of the ionic strength of the buffered solution in a salt concentration range from 5 to 100 millimolar. A photophysical relaxation mechanism that satisfactorily explains the excitation wavelength dependence of the fluorescence quantum yield of tryptophan will be presented.https://commons.case.edu/intersections-fa20/1002/thumbnail.jp

Advanced titanium scaffolds obtained by directional freeze-drying: on the influence of processing conditions

Ministry of Science and Innovation of Spain under Grant No. MAT2010-20855Junta de Andalucía (Spain) / FEDER (EU), through the project Ref. P12-TEP-140

Static Model of Cement Rotary Kiln

En este trabajo, se presenta un modelo estático de un horno rotatorio de cemento. El modelo del sistema se obtiene a través de series de polinomio. El modelo propuesto se verifica con datos reales de la planta, donde se obtuvieron resultados óptimos. Los resultados esperados son medidos con respecto a la producción de Clinker. El consumo de combustible se mide en relación con el consumo calorífico. Los resultados esperados del enfoque es el incremento de los beneficios de la empresa a través de la reducción en el consumo de combustible.In this paper, a static model of cement rotary kilns is proposed. The system model is obtained through polynomial series. The proposed model is contrasted with data of a real plant, where optimal results are obtained. Expected results are measured with respect to the clinker production and the combustible consumption is measured in relation with the consumption calorific. The expected result of the approach is the increase of the profitability of the factory through the decrease of the consumption of the combustible