Feature selection algorithms: a survey and experimental evaluation

In view of the substantial number of existing feature selection algorithms, the need arises to count on criteria that enables to adequately decide which algorithm to use in certain situations. This work reviews several fundamental algorithms found in the literature and assesses their performance in a controlled scenario. A scoring measure ranks the algorithms by taking into account the amount of relevance, irrelevance and redundance on sample data sets. This measure computes the degree of matching between the output given by the algorithm and the known optimal solution. Sample size effects are also studied.Postprint (published version

First clear evidence of quantum chaos in the bound states of an atomic nucleus

We study the spectral fluctuations of the $^{208}$Pb nucleus using the complete experimental spectrum of 151 states up to excitation energies of $6.20$ MeV recently identified at the Maier-Leibnitz-Laboratorium at Garching, Germany. For natural parity states the results are very close to the predictions of Random Matrix Theory (RMT) for the nearest-neighbor spacing distribution. A quantitative estimate of the agreement is given by the Brody parameter $\omega$, which takes the value $\omega=0$ for regular systems and $\omega \simeq 1$ for chaotic systems. We obtain $\omega=0.85 \pm 0.02$ which is, to our knowledge, the closest value to chaos ever observed in experimental bound states of nuclei. By contrast, the results for unnatural parity states are far from RMT behavior. We interpret these results as a consequence of the strength of the residual interaction in $^{208}$Pb, which, according to experimental data, is much stronger for natural than for unnatural parity states. In addition our results show that chaotic and non-chaotic nuclear states coexist in the same energy region of the spectrum.Comment: 9 pages, 1 figur

Stress-strain response and microstructural evolution of a FeMnCAl TWIP steel during tension-compression tests

© 2016. The stress-strain response of a Fe-17.5Mn-0.7C-2Al TWIP steel during cyclic loading has been investigated by means of tension-compression tests within the strain limits of ±2%, ±5% and ±10%. In addition, the microstructural evolution during the ±5% cyclic test has also been studied. The difference between the forward and reverse stress for each pre-strain has been analyzed at 0.2% offset strain and at the strains in which forward and reverse curves were parallel in order to study the Bauschinger effect (BE) and permanent softening, respectively. The evolution of the BE with pre-strain for this steel is similar to other FeMnC TWIP steels, that is, increasing values of BE are obtained as the pre-strain increases. However, its absolute values are half those reported in the literature on other FeMnC steels. This diminution of the BE is related to the lower activity of mechanical twinning in FeMnCAl TWIP steels at the pre-strains herein investigated, which promotes less polarized stresses in the matrix due to the lower dislocation storage capacity.Regarding permanent softening, the evolution is similar to that of the BE and the same analysis can be applied. During reverse compression, a slight increase of twin thickness and twin spacing with respect to the first tensile stage took place. This fact might be linked to the lower flow stress observed in the permanent softening period during reverse straining.Peer ReviewedPostprint (author's final draft

Nanopartículas Poliméricas en Dermocosmética

Indexación: Web of Science; Scielo.Recent advances in the fields of biomaterials and nanotechnology have allowed the development of advanced nanoparticles for biomedical applications. Despite a vast number of nanostructures such as liposomes, solid­lipid nanocapsules, polymeric and hybrid lipid­polymer nanoparticles have been studied as carriers for drug delivery for different pathologies with remarkable promising results; the use of polymeric nanoparticles in dermocosmetic still has not been widely explored. The evolution of cosmetic into the care skin and dermatology represents novel technological challenges. Also, the increasing knowledge about normal skin physiology and advances in nanotechnology provide an attractive environment for the creation of innovative dermocosmetic formulations. In this work, we discuss the state of the art of polymeric nanoparticles formulated for dermocosmetics, its mechanisms of action, and diffusion into the skin.Los recientes avances en el campo de los biomateriales y la nanotecnología han permitido el desarrollo de nanopartículas avanzadas para aplicaciones biomédicas. A pesar de que un gran número de nanoestructuras tales como liposomas, nanocápsulas lípido-sólidas, nanopartículas poliméricas y lípido-polímero híbridas han sido estudiadas como vehículos para la administración de fármacos en diferentes patologías con notables resultados prometedores, el uso de nanopartículas poliméricas en dermocosmética todavía no ha sido ampliamente explorado. La evolución de la cosmética en el cuidado de la piel y la dermatología nos enfrentan a nuevos retos tecnológicos. Además, el aumento de los conocimientos sobre la fisiología de la piel normal y los avances en la nanotecnología proporcionan un entorno atractivo para la creación de formulaciones dermocosméticas innovadoras. En este trabajo se discute el estado del arte de las nanopartículas poliméricas desarrolladas para dermocosmética, sus mecanismos de acción y la difusión en la piel.http://ref.scielo.org/b68hz

Designing selection indices for the florida dairy goat breeding program

The aim of this study was to compare selection indices for important traits in intensive Spanish goat breeds in four economic scenarios, using the Florida as most representative breed of this production system in Spain. For this analysis, we considered the following traits: milk yield (MY), fat plus protein yields (FPY), casein yield (CY), somatic cell score (SCS), reproductive efficiency (RE), litter size (LS), mammary system (MS), final score (FS), body capacity index (BCI), and length of productive life (LPL). We estimated the genetic parameters and EBVs of most of these traits with REML methodology, while LPL was modeled through survival analysis. Four scenarios were proposed, depending on the overall objective for improvement: (1) milk production, (2) milk production and cheese extract, (3) cheese extract, and (4) milk production, cheese extract and sale of animals. Then, within each scenario, three different types of indices were designed using the different primary and secondary objectives/criteria considered suitable to improve the overall objective. The results indicated that selecting only for primary traits yielded the highest genetic response for all the scenarios. Including secondary traits led to positive correlated responses in those traits, but a decrease in the responses in the primary criteria

Theoretical derivation of 1/f noise in quantum chaos

It was recently conjectured that 1/f noise is a fundamental characteristic of spectral fluctuations in chaotic quantum systems. This conjecture is based on the behavior of the power spectrum of the excitation energy fluctuations, which is different for chaotic and integrable systems. Using random matrix theory we derive theoretical expressions that explain the power spectrum behavior at all frequencies. These expressions reproduce to a good approximation the power laws of type 1/f (1/f^2) characteristics of chaotic (integrable) systems, observed in almost the whole frequency domain. Although we use random matrix theory to derive these results, they are also valid for semiclassical systems.Comment: 5 pages (Latex), 3 figure

Recent advances of synthesis of Boron derivatives and their applications in bioimaging

The increasing interest in the luminescent boron materials is due to their potential application in diverse areas such as solar cells, optoelectronic devices, and biological imaging materials. Continuous search for the compounds with better properties, luminescent organoboron materials have been gaining more importance, especially in the development of new technologies and novel techniques for bioimaging, which is a powerful tool to analyze the cellular organelles with important value into the cell biology and medical research. Synthesis, properties, and applications of luminescent boron compounds and their application in bioimaging are reviewed.

Respuestas de la caña (Saccharum officinarum L.) variedad POJ 2878, a dosis y fuentes de fósforo en suelos de ladera en Antioquia

ICA's soil program established four trials in Sugarcane, variety POJ 28-78 in Cocorná, Barbosa and Arnagá (counties located in Antioquia). The red soils of these places were slope, strongly acids, low to high in organic matter (1,6 to 17,69o) and low in P-available (1,5 to 3,2 ppm-Bray II), Ca, Mg and K-exchangeable. The main object of these trials was to study the effect of different sources of phosphorus: Superphosphate (SF1), Thomas Slags (ET) and Rock Phosphate (RF) and two dosages (75 and 150 kg/Ha of P205) in yields of sugarcane (TCA), sugar (TAH) and saccharose concentration. The results showed good yields (TCH and TAH) and saccharose concentration with 75 - 150 kg/Ha of P205 of SF1 and ET or 150 kg/Ha of P205 with RF at planting time and first cut.Entre 1.976 y 1.980 el Programa de Suelos del ICA, con sede en la Estación Experimental Tulio Ospina, estableció tres ensayos de caña para la producción de panela con la variedad POJ 28-78 en los municipios de Cocorná, Barbosa y Amagá. Los suelos estudiados pertenecen a una zona de vida natural de bosque húmedo premontano (bh-PM) caracterizada por altura sobre el nivel del mar de 900 a 1.400 metros, 21 y 24 grados centìgrados de temperatura media mensual y 1.000 a 2.000 milímetros de precipitación anual. Esta formación vegetal es representativa de unas 70 a 80 mil hectáreas cultivadas con caña panelera en el departamento de Antioquia. Los suelos donde se establecieron los ensayos presentan topografía ondulada o quebrada, están fuertemente erosionados y poseen color pardo rojizo y buen drenaje natural. Químicamente se caracterizan por reacción fuertemente ácida y por ser de fertilidad natural baja, medios a altos en materia orgánica, bajos en P aprovechable cuando éste se extrae por Bray II (1,5 a 3,2 ppm) y bajos también en las bases intercambiables Ca, Mg, K y Na. El objetivo principal de los ensayos fue evaluar tres fuentes de P: superfosfato triple (soluble en agua y citrato), Escorias Thomas (soluble en citrato) y una roca fosfórica de origen colombiano (insoluble en agua y citrato) en las dosis de 0, 75 y 150 kg/Ha de P205. Las dosis estudiadas se aplicaron en el momento de la siembra e inmediatamente después del primer corte. Además de las dosis de P205 se fertilizó con 150 kg/Ha de N y de K20 más 500 kg/Ha de cal dolomìtica (40% de CaCO3 y 8%de MgCO3). Se midieron los efectos de la fertilización fosfatada en las toneladas de caña por hectárea (TCH), toneladas de azúcar por hectárea (TAH) y en la concentración de sacarosa en el corte de plantilla y de primera soca. Los resultados mostraron incrementos significativos tanto en producción de caña (TCH) como en rendimiento en azúcar (TAH) y concentración de sacarosa cuando se aplica cualquiera de las tres fuentes de fósforo estudiadas. Las dosis màs eficientes agronómicamente para plantilla y primera soca fueron las de 75 kg/Ha de P205 y 150 kg/Ha, respectivamente, aplicadas como superfosfato triple y Escorias Thomas. La roca fosfórica, en dosis de 150 kg/Ha de P205, permite rendimientos altos de caña, de azúcar y también alta concentración de sacarosa cuando se aplica en cada cosecha. El método Bray II de extracción de P permite predecir buena respuesta de los suelos estudiados a la aplicación de fertilizantes fosfatados cuando el contenido de P aprovechable es menor de cinco partes por millón.Caña panelera-Saccharum officinarum - Saccharum officinarum L