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

Terneros de raza retinta en cebadero: análisis individual y por lotes

La raza Retinta dispone de un censo aproximado de 200.000 reproductoras de las cuales más de un 10% están inscritas en el Libro Genealógico de la raza. Representa el 5,3% del bovino español y el 14,5% del autóctono. En este trabajo se ha controlado el cebo de 373 terneros machos retintos puros procedentes de la ganadería del Centro Experimental Agrícola Ganadero de Jerez de la Frontera de la Excma. Diputación de Cádiz. Los animales se controlaron desde el destete hasta que fueron sacrificados, pesándolos con periodicidad mensual, con un total de 1984 pesadas, de las cuales 373 corresponden a la pesada de entrada en cebadero, 1.238 han sido pesadas durante el período de cebo y 373 pesadas al sacrificio. La duración media del cebo fue 158,5±2,8 días (cv 34,2%). El período medio de aclimatación al cebo tuvo una duración media de 32,6±Q,9 días, iniciándose el cebo los terneros con una edad media de 226,5±1,5 días y un peso de 27 1,3±2,6 kg. El peso promedio al sacrificio en todo el período analizado (l a años) fue de 518,0±3,9 kg (con un cv del 14,6%). El 70% de los animales se sacrificaron con un peso comprendido entre los 450 y 600 Kg resultando una ganancia media diaria (GMD) global de 1,58±O,012 kg/día (cv del 14,1 %) con un valor mínimo de 0,76 kg/día y un máximo de 2,27. Se puede resaltar que el 14% de los terneros presentaron una GMD superior a los 2 Kg/día. Se obtuvo un índice de transformación global (IT) de 5,29 y un consumo medio diario por animal (CMD) de 8,77 kg. Los valores medios de los lotes cebados en los dos últimos años presentaron un peso al sacrificio de 575,2 kg para una duración del cebo de 175,9.±4,2 días y una GMD de 1,6 Kg/día. La media del IT fue de 5,18 y del CMD de 8,98 Kg, con unos c.v. del 5,93% y del 5,23% respectivamente. Se han estudiado los factores que influyen sobre las variables peso de sacrificio y GMD en cebo mediante un ANOVA multifa ctorial. La paridera y la época de inicio del cebo han sido algunos de los factores de influencia

Trophic models and short-term dynamic simulations for benthic-pelagic communities at Banco Chinchorro Biosphere Reserve (Mexican Caribbean): a conservation case

Banco Chinchorro is the largest reef in the Mexican Caribbean. Historically, spiny lobster, queen conch and over 20 other reef species have been exploited here. Multispecies intervention management from an ecosystem perspective has been developed in this area; however, an assessment of the effects of such practices on ecosystem health is required. Five quantitative trophic models were constructed using Ecopath with Ecosim. The results show that, in terms of biomass, benthic autotrophs are the dominant group in all communities. Ecosystem Network Analysis indices showed that Cueva de Tiburones was the most mature, developed, complex and healthy subsystem, but, El Colorado and La Baliza were the subsystems most resistant to disturbances. The fisheries mainly concentrate on primary (La Baliza and Cueva de Tiburones sites) and secondary consumers (La Caldera, Chancay, and El Colorado). The greatest propagation of direct and indirect effects, estimated by Mixed Trophic Impacts and Ecosim simulations, were generated by the benthic autotrophs, small benthic epifauna, benthic-pelagic carnivorous fish and benthic carnivorous fish, among others. In contrast, the System Recovery Time showed different patterns among subsystems, indicating several compartments that reduce resilience. Considering the structure, dynamics, trophic functioning and ecosystem health of Banco Chinchorro, its ecological heterogeneity highlights the need for the design of a specific (by subsystem) management strategy, particularly because different species or functional groups present greater sensitivity to human interventions in each community

A Structural Parametrization of the Brain Using Hidden Markov Models Based Paths in Alzheimer's Disease

The usage of biomedical imaging in the diagnosis of dementia is increasingly widespread. A number of works explore the possibilities of computational techniques and algorithms in what is called Computed Aided Diagnosis. Our work presents an automatic parametrization of the brain structure by means of a path generation algorithm based on Hidden Markov Models. The path is traced using information of intensity and spatial orientation in each node, adapting to the structural changes of the brain. Each path is itself a useful way to extract features from the MRI image, being the intensity levels at each node the most straightforward. However, a further processing consisting of a modification of the Gray Level Co-occurrence Matrix can be used to characterize the textural changes that occur throughout the path, yielding more meaningful values that could be associated to the structural changes in Alzheimer's Disease, as well as providing a significant feature reduction. This methodology achieves high performance, up to 80.3\% of accuracy using a single path in differential diagnosis involving Alzheimer-affected subjects versus controls belonging to the Alzheimer's Disease Neuroimaging Initiative (ADNI).TIC218, MINECO TEC2008-02113 and TEC2012-34306 projects, Consejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía P09-TIC-4530 and P11-TIC-71

Acción de venenos ofídicos del género Bothrops (yarará) sobre la membrana de eritrocitos de carnero

El estudio de la resistencia globular osmótica (RGO) es importante en la determinación de ciertos problemas clínicos, como así también modificaciones morfológicas de la membrana plasmática del eritrocito. Glóbulos rojos de carneros fueron incubados con veneno de serpientes del género Bothrops (B. diporus, B. jararaca, B. jararacussu, B. moojeni) durante 30 minutos a 37ºC. Posteriormente fueron sometidos a soluciones de NaCl de osmolaridad decreciente (0,85 a 0,20 g/l), incubándose a 4ºC durante un máximo de 3 horas, para luego leer en espectrofotómetro la absorbancia del sobrenadante a 540 nm. Los eritrocitos incubados con los distintos venenos también fueron examinados al microscopio óptico y electrónico de barrido. Todos los venenos ensayados mostraron un comportamiento similar, siendo la RGO mínima de 0,70 g/l de NaCl y la máxima de 0,20 g/l, excepto para el veneno de B. jararacussu que causó hemólisis máxima con 0,50 g/l. La microscopía óptica mostró eritrocitos con poiquilocitosis y espiculados; mayores alteraciones de la membrana plasmática fueron detectadas por microscopía electrónica de barrido. Algunos venenos indujeron daños más severos que otros; en general se registró disminución del tamaño celular, mientras que con el veneno de B. jararacussu la mayoría de las células presentaba destrucción de su membrana. Se resalta que el presente estudio es un ensayo in vitro, y que en un paciente con accidente de mordedura, los eventos ocurren con participación de componentes endógenos que configuran un entorno diferente, facilitando o impidiendo la actividad lítica

Estudio Preliminar Sobre La Decoloración Del Residual Líquido De La Producción De Papel Mediante Ozonización

Preliminarily, the relationship between Color Reduction (%RC), Total Suspended Solids concentration (SST), and as independent variable, the time of Ozone Oxidation Process, was evaluated with reference values of DQO of the black liquor adjusting its concentration from SST to 300 and 50mg/dm3. A batch reactor of 12,60dm3, an effective height of 3,2dm and an ozone generating device from SEFILTRA company (air flow of 2dm3/min, c(O3) of 9,50mg/dm3 with a O3(g) production 19mg/min) was used. The polynomic correlation was determined from 192 data sets with satisfactory adjustment level (R=0,92; p <0,001). Although, preliminarily, the DQO reduction (%RDQO) was not included in the polynomial relationship, it can be concluded that: a) The %RC and %RDQO is reduced when color and DQO increases from the ozonized sample at same time intervals; this reduction is greater when the SST levels of the ozonized sample increases. b) The %RC and %RDQO decrease when the SST level of the ozonized sample increases. c) Depending on the initial color, of the DQO and of the SST level of the sample, values from 10 to 53 %Rc were obtained after 10 min, and of 66 to 94 %Rc after 60 min

Urban landscape influences the composition of butterflies in public parks and fragments in Southern Brazil

Abstract Terrestrial ecosystems across the world experience large-scale and widespread urbanization, causing a sharp decline, fragmentation and segregation of natural landscapes. Nevertheless, fragments of natural habitats that are found within the largest cities may still be capable of preserving high species diversity that amount to a large portion of the regional biodiversity. Knowing which variables of the urban landscape promote the conservation of species' assemblages in large cities helps us to implement measures that support biodiversity conservation. We sampled the butterfly assemblages of eight urban forest fragments in Curitiba (Southern Brazil), from September 2015 to April 2016. At each site, richness, diversity and composition of butterflies were estimated and then correlated to nine landscape variables measured at two spatial scales (buffers of 250 and 750m). A total of 298 species were recorded in these fragments, representing 53.7% of all species known to occur in the city. Despite of great difference in the size of the fragments (between 27 and 56.3 ha), there were no significant differences in species richness among the fragments. On the other hand, some significant correlations were observed between landscape variables and butterfly composition other than the fragment itself, such as the paved area and total forested area present around the fragments. These results reinforce the idea that the conservation of natural fragments in urban areas requires public policies that enhance not only the habitat quality of the fragment itself, but also enrichment of the landscape around them