Topological first-order solitons in a gauged CP(2)CP(2) model with the Maxwell-Chern-Simons action

We verify the existence of radially symmetric first-order solitons in a gauged $CP(2)$ scenario in which the dynamics of the Abelian gauge field is controlled by the Maxwell-Chern-Simons action. We implement the standard Bogomol'nyi-Prasad-Sommerfield (BPS) formalism, from which we obtain a well-defined lower bound for the corresponding energy (i.e. the Bogomol'nyi bound) and the first-order equations saturating it. We solve these first-order equations numerically by means of the finite-difference scheme, therefore obtaining regular solutions of the effective model, their energy being quantized according the winding number rotulating the final configurations, as expected. We depict the numerical solutions, whilst commenting on the main properties they engender.Comment: 8 pages, 9 figure

Parent Stars of Extrasolar Planets. X. Lithium Abundances and vsini Revisited

We determine Li abundances and vsini values from new spectra of 53 stars with Doppler-detected planets not included in our previous papers in this series. We also examine two sets of stars without detected planets, which together serve as our comparison sample. Using the method of comparison of Li abundances and vsini values between two sets of stars we introduced in Gonzalez (2008), we confirm that these two quantities are smaller among stars with planets compared to stars without detected planets near the solar temperature. The transition from low to high Li abundance among SWPs occurs near 5850 K, a revision of about 50 K from our previous determination. The transition from low to high vsini occurs near 6000 K, but this temperature is not as well constrained.Comment: accepted for publication in MNRAS; 14 pages, 13 figures, 3 table

Desarrollo de la competencia mediática : el uso de internet en casa para hacer las tareas escolares

Internet forma ya parte de la vida cotidiana de buena parte de la sociedad. En los últimos años, su uso se ha consolidado en los hogares españoles, principalmente como un recurso para el ócio. Sin embargo, Internet es una herramienta que también puede ser utilizada con fines educativos. Concretamente, la presente exposición, plantea su uso para la realización de los deberes de casa, para lo cual es imprescindible la alianza entre la escuela y la familia. El objetivo educativo que se plantea trasciende el uso instrumental de Internet, y persigue el desarrollo de la competencia mediática y digital en los estudiantes de infantil y primaria Esto es fundamental, en una sociedad actual donde el paradigma de la comunicación 2.0 permite que todas las personas sean activas en la comunicación, no ya como simples receptores sino también como emisores (prosumidores). Por tanto, el gran reto es la formación crítica en alfabetización digital desde la infancia. Sólo de esta manera, educadores y padres pueden formar integralmente a los niños y niñas en el uso adecuado y pertinente de la tecnología, acompañándolos para que puedan afrontar un uso seguro de Internet (ya que dejarlos solos en el ciberespacio conlleva múltiples riesgos). La presente exposición toma como eje un estudio colaborativo disponible en línea, con la pretensión de plantear algunas sugerencias para el uso de Internet en las tareas escolares en casa. De esta manera, se sugieren actividades en las que los alumnos tengan que realizar acciones tan diversas como buscar y seleccionar información, transformar la información en conocimiento, crear, presentar, comunicarse, colaborar…utilizando las TIC. En esta presentación se pretende, en definitiva, evidenciar las ventajas de crear hábitos de estudio y sacar provecho del potencial de la web para generar conocimiento y desarrollar la autonomía del estudiante

Exposición crónica a hongos productores de aflatoxinas relacionada a daños hepáticos en chinchillas (chinchilla lanigera) destinadas a la producción de piel

Chinchilla pelt is a rare and expensive fur. Therefore, breeding these animals is a profitable activity. Confirmed acute cases of aflatoxin intoxication have been reported in Argentinean farms. The aims of this study were i) to evaluate mycobiota and AFB1 -producing species in chinchilla feeds ii) to investigate their natural AFB1 contamination and iii) to analyze histopathological lesions in chinchilla livers. Feed samples (A: fur chinchillas, B: mother chinchillas, C: lucerne cubes) were collected from a factory and a farm. Livers of sacrificed chinchilla from the farm were macroscopically and microscopically examined. Total fungal counts of feed C exceeded 1x104 CFU g-1. Aspergillus, Fusarium and Penicillium were the prevalent genera, while A. flavus, A. fumigatus, F. verticillioides and F. proliferatum were the prevalent species. 50 % of A. flavus strains from factory samples and 69.7 % from farm samples produced 2.78 to 8. 64 µg g-1 and 0.66 to 58.8 µg g-1 AFB1 , respectively. Aflatoxin B1 was detected only in feeds from the farm, finding the highest incidence in feed C. Toxin levels varied between 1.90 and 97.34 µg kg-1 AFB1 . Mean levels in feed A and C exceeded 20 µg kg-1. Macroscopic examination of livers revealed normal appearance, size and color. However, histopathological examination indicated 63.3 % showed slight to moderate lipid degeneration with diffuse cytoplasm vacuolation, 9 % intense lipid cytoplasm vacuolation and 27.3 % hydropic degeneration and nuclear vacuolation in hepatocytes. A periodic monitoring of aflatoxins in feeds and their ingredients can prevent acute outbreaks and economic losses caused by chronic exposure.La piel de chinchilla es una de las más exóticas y apreciadas en el mercado internacional. La cría de estos animales es una actividad muy rentable. En Argentina, se han detectado casos de aflatoxicosis aguda en criaderos. Los objetivos de este trabajo fueron: i) estudiar la micobiota y los hongos productores de aflatoxina B1 (AFB1 ) presentes en alimento para chinchillas. ii) analizar la contaminación natural con AFB1 de estos alimentos iii) buscar lesiones histopatológicas en hígados de chinchillas de los criaderos. Se recolectaron muestras de diferentes alimentos (A: chinchilla piel, B: chinchilla madre, C: cubos de alfalfa) en una fábrica y un criadero localizados en la ciudad de Rio Cuarto, en la región central de Argentina. Los hígados de las chinchillas sacrificadas en el criadero fueron analizados macroscópica y microscópicamente. Los recuentos fúngicos totales fueron mayores a 1x104 UFC g-1. Aspergillus, Fusarium y Penicillium fueron los géneros prevalentes, mientras que A. flavus, A. fumigatus, F. verticillioides y F. proliferatum fueron las especies aisladas con mayor frecuencia. 50 % de las cepas de A. flavus aisladas de la fábrica y 69.7 % de las aisladas del criadero produjeron 2.78 a 8.64 µg g-1 y 0.66 a 58.8 µg g-1 de AFB1 , respectivamente. Se detectó AFB1 sólo en las muestras del criadero, con mayor incidencia en el alimento C. Los niveles de toxina variaron entre 1.90 y 97.34 µg kg-1. Los niveles promedios en A y C fueron superiores a 20 µg kg-1. El análisis macroscópico de los hígados reveló apariencia, tamaño y color normal. El análisis microscópico indicó que 63.3 % de los hígados presentaron degeneración lipídica leve a moderada con vacuolización difusa del citoplasma, 9 % presentaron vacuolización lipídica intensa y 27.3 % degeneración hidrópica y vacuolización nuclear en los hepatocitos. El monitoreo periódico de La calidad de los alimentos e ingredientes usados en la alimentación de chinchillas puede evitar intoxicaciones agudas y pérdidas económicas causadas por la exposición crónica a aflatoxinas.Fil: Landa, Maria Florencia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gonzalez Pereyra, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pena, Gabriela Alejandra. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bagnis, Guillermo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Cavaglieri, Lilia Reneé. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rosa, Carlos Alberto da Rocha. Conselho Nacional de Pesquisas Científicas; BrasilFil: Dalcero, Ana Maria. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

A Fast and Accurate Nonlinear Spectral Method for Image Recognition and Registration

This article addresses the problem of two- and higher dimensional pattern matching, i.e. the identification of instances of a template within a larger signal space, which is a form of registration. Unlike traditional correlation, we aim at obtaining more selective matchings by considering more strict comparisons of gray-level intensity. In order to achieve fast matching, a nonlinear thresholded version of the fast Fourier transform is applied to a gray-level decomposition of the original 2D image. The potential of the method is substantiated with respect to real data involving the selective identification of neuronal cell bodies in gray-level images.Comment: 4 pages, 3 figure

Phantom Friedmann Cosmologies and Higher-Order Characteristics of Expansion

We discuss a more general class of phantom ($p < -\varrho$) cosmologies with various forms of both phantom ($w -1$) matter. We show that many types of evolution which include both Big-Bang and Big-Rip singularities are admitted and give explicit examples. Among some interesting models, there exist non-singular oscillating (or "bounce") cosmologies, which appear due to a competition between positive and negative pressure of variety of matter content. From the point of view of the current observations the most interesting cosmologies are the ones which start with a Big-Bang and terminate at a Big-Rip. A related consequence of having a possibility of two types of singularities is that there exists an unstable static universe approached by the two asymptotic models - one of them reaches Big-Bang, and another reaches Big-Rip. We also give explicit relations between density parameters $\Omega$ and the dynamical characteristics for these generalized phantom models, including higher-order observational characteristics such as jerk and "kerk". Finally, we discuss the observational quantities such as luminosity distance, angular diameter, and source counts, both in series expansion and explicitly, for phantom models. Our series expansion formulas for the luminosity distance and the apparent magnitude go as far as to the fourth-order in redshift $z$ term, which includes explicitly not only the jerk, but also the "kerk" (or "snap") which may serve as an indicator of the curvature of the universe.Comment: REVTEX 4, 23 pages, references updated, to appear in Annals of Physics (N.Y.

Evolved stars hint to an external origin of enhanced metallicity in planet-hosting stars

Exo-planets are preferentially found around high metallicity main sequence stars. We aim at investigating whether evolved stars share this property, and what this tells about planet formation. Statistical tools and the basic concepts of stellar evolution theory are applied to published results as well as our own radial velocity and chemical analyses of evolved stars. We show that the metal distributions of planet-hosting (P-H) dwarfs and giants are different, and that the latter do not favor metal-rich systems. Rather, these stars follow the same age-metallicity relation as the giants without planets in our sample. The straightforward explanation is to attribute the difference between dwarfs and giants to the much larger masses of giants' convective envelopes. If the metal excess on the main sequence is due to pollution, the effects of dilution naturally explains why it is not observed among evolved stars. Although we cannot exclude other explanations, the lack of any preference for metal-rich systems among P-H giants could be a strong indication of the accretion of metal-rich material. We discuss further tests, as well as some predictions and consequences of this hypothesis.Comment: A&A, in pres

In situ studies of materials for high temperature CO2 capture and storage.

Carbon capture and storage (CCS) offers a possible solution to curb the CO2 emissions from stationary sources in the coming decades, considering the delays in shifting energy generation to carbon neutral sources such as wind, solar and biomass. The most mature technology for post-combustion capture uses a liquid sorbent, amine scrubbing. However, with the existing technology, a large amount of heat is required for the regeneration of the liquid sorbent, which introduces a substantial energy penalty. The use of alternative sorbents for CO2 capture, such as the CaO-CaCO3 system, has been investigated extensively in recent years. However there are significant problems associated with the use of CaO based sorbents, the most challenging one being the deactivation of the sorbent material. When sorbents such as natural limestone are used, the capture capacity of the solid sorbent can fall by as much as 90 mol% after the first 20 carbonation-regeneration cycles. In this study a variety of techniques were employed to understand better the cause of this deterioration from both a structural and morphological standpoint. X-ray and neutron PDF studies were employed to understand better the local surface and interfacial structures formed upon reaction, finding that after carbonation the surface roughness is decreased for CaO. In situ synchrotron X-ray diffraction studies showed that carbonation with added steam leads to a faster and more complete conversion of CaO than under conditions without steam, as evidenced by the phases seen at different depths within the sample. Finally, in situ X-ray tomography experiments were employed to track the morphological changes in the sorbents during carbonation, observing directly the reduction in porosity and increase in tortuosity of the pore network over multiple calcination reactions