Bead, Hoop, and Spring as a Classical Spontaneous Symmetry Breaking Problem

We describe a simple mechanical system that involves Spontaneous Symmetry Breaking. The system consists of two beads constrained to slide along a hoop and attached each other through a spring. When the hoop rotates about a fixed axis, the spring-beads system will change its equilibrium position as a function of the angular velocity. The system shows two different regions of symmetry separated by a critical point analogous to a second order transition. The competitive balance between the rotational diynamics and the interaction of the spring causes an Spontaneous Symmetry Breaking just as the balance between temperature and the spin interaction causes a transition in a ferromagnetic system. In addition, the gravitational potential act as an external force that causes explicit symmetry breaking and a feature of first-order transition. Near the transition point, the system exhibits a universal critical behavior where the changes of the parameter of order is described by the critical exponent beta =1/2 and the susceptibility by gamma =1. We also found a chaotic behavior near the critical point. Through a demostrative device we perform some qualitative observations that describe important features of the system.Comment: 7 pages, 2 tables, 30 figures, LaTeX2

Contribución al estudio florístico de las serranías subbéticas de la provincia de Sevilla

A check—list of the Sierras Subbéticas of the province of Seville is presented. A total of 883 species have been identificated. The geographical, geological, edaphological and climatological characters, are also give.En este trabajo se ha realizado un catálogo florístico de la Sierras Subbéticas de la provincia de Sevilla, en el que se citan 882 especies. Dicho catálogo va acompañado de las componentes geográficas, geológicas, edafológicas y climatológicas que caracterizan la zona. A check—list of the Sierras Subbéticas of the province of Seville is presented. A total of 883 species have been identificated. The geographical, geological, edaphological and climatological characters, are also give

Globalización y fragmentación del territorio en el extremo oriente paraguayo

Dissertação apresentada ao Programa de Pós-Graduação em Integração Contemporânea da América Latina da Universidade Federal da Integração Latino-Americana, como requisito parcial à obtenção do título de Mestre em Integração Latino-Americana.El objetivo principal es el de problematizar la fragmentación de los territorios en el período actual. La literatura sobre la globalización suele venir acompañada de discursos que festejan el acortamiento de las distancias o el fin de las fronteras políticas. Entendemos que, muy por lo contrario, el fenómeno de compartimentación de los territorios cobra un nuevo sentido. La producción horizontal de las fronteras, propia de períodos anteriores al nuestro, es resignificada hoy en día con los avances de las tecnologías de transportes y comunicación. Cada vez más variables lejanas, ajenas al lugar, determinan las formas y las funcionalidades de las fronteras —principalmente en nuestros países—. En vista de ello preferimos comprender la compartimentación espacial como fragmentación territorial. Para tanto, nuestro recorte analítico fue delimitado en torno a las modernizaciones territoriales en la frontera oriental del Paraguay (con destaque para el Alto Paraná), en la segunda mitad del siglo XX. El extremo oriente es el ejemplo mejor acabado de la expansión del medio técnico-científico-informacional en territorio paraguayo (exceptuando la región metropolitana de Asunción). La mayor densidad del territorio en la frontera este, y en el departamento de Alto Paraná en particular, en términos de tecnología e información se debe, en buena medida, a la importancia de la agricultura científica. Fueron fundados centros urbanos funcionales al avance de la frontera agrícola en Alto Paraná y Canindeyú. Este hecho solo cobra significado si se lo examina al lado del intenso movimiento migratorio brasileño hacia esta región entre las décadas de 1960 y 1990. De ahí que las fronteras internas en el extremo oriente paraguayo presenten un ritmo acelerado de evolución, sobre todo, en la década de 1990

Investigation of optical and physico-chemical properties of titanium-doped V2O5 nanofilms

In this paper, undoped and Ti-doped V2O5 thin films were fabricated and deposited onto glass substrates using a > method. Then, the effects of Ti-doping on the optical properties of the thin films were investigated. Titanium doping concentration of 0.25-0.75 at.% has been investigated. After treatment in air at different temperatures, the obtained films was characterised by various techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL). It was found that the as-obtained doped films possessed thermochromic properties and optical switching characters. According to optical tests, thin linings of vanadium dioxide alloyed with Ti have optical properties that are effective for application. Because of their capacity to automatically control interior solar irradiation, lower air-conditioning energy consumption, and maintain a comfortable internal thermal climate, smart windows have drawn increased interest in recent years. The doping strategy and integrating with functional coatings can regulate the properties of obtained V2O5 films.6 página

Contribución al estudio florístico de las serranías subbéticas de la provincia de Sevilla

A check-list of the Sierras Subbéticas of the province of Seville is presented. A total of 883 species have been identificated. The geographical, geological, edaphological and climatological characters, are also give.En este trabajo se ha realizado un catálogo florístico de la Sierras Subbéticas de la provincia de Sevilla, en el que se citan 882 especies. Dicho catálogo va acompañado de las componentes geográficas, geológicas, edafológicas y climatológicas que caracterizan la zona

Reliable resolution of ambiguous hepatitis C virus genotype 1 results with the Abbott HCV Genotype Plus RUO assay

Hepatitis C; Genotype; Abbott HCVHepatitis C; Genotip; Abbott HCVHepatitis C; Genotipo; Abbott HCVAccurate subtyping of hepatitis C virus genotype 1 (HCV-1) remains clinically and epidemiologically relevant. The Abbott HCV Genotype Plus RUO (GT Plus) assay, targeting the core region, was evaluated as a reflex test to resolve ambiguous HCV-1 results in a challenging sample collection. 198 HCV-1 specimens were analysed with GT Plus (38 specimens with and 160 without subtype assigned by the Abbott RealTime Genotype II (GT II) assay targeting the 5'NC and NS5B regions). Sanger sequencing of the core and/or NS5B regions were performed in 127 specimens without subtype assignment by GT II, with "not detected" results by GT Plus, or with mixed genotypes/subtypes. The remaining GT Plus results were compared to LiPA 2.0 (n = 45) or just to GT II results if concordant (n = 26). GT Plus successfully assigned the subtype in 142/160 (88.8%) samples. "Not detected" results indicated other HCV-1 subtypes/genotypes or mismatches in the core region in subtype 1b. The subtyping concordance between GT Plus and either sequencing or LiPA was 98.6% (140/142). Therefore, combined use of GT II and GT Plus assays represents a reliable and simple approach which considerably reduced the number of ambiguous HCV-1 results and enabled a successful subtyping of 98.9% of all HCV-1 samples

TMEM16A calcium-activated chloride currents in supporting cells of the mouse olfactory epithelium

Glial-like supporting (or sustentacular) cells are important constituents of the olfactory epithelium that are involved in several physiological processes such as production of endocannabinoids, insulin, and ATP and regulation of the ionic composition of the mucus layer that covers the apical surface of the olfactory epithelium. Supporting cells express metabotropic P2Y purinergic receptors that generate ATP-induced Ca2+ signaling through the activation of a PLC-mediated cascade. Recently, we reported that a subpopulation of supporting cells expresses also the Ca2+-activated Cl- channel TMEM16A. Here, we sought to extend our understanding of a possible physiological role of this channel in the olfactory system by asking whether Ca2+ can activate Cl- currents mediated by TMEM16A. We use whole-cell patch-clamp analysis in slices of the olfactory epithelium to measure dose-response relations in the presence of various intracellular Ca2+ concentrations, ion selectivity, and blockage. We find that knockout of TMEM16A abolishes Ca2+-activated Cl- currents, demonstrating that TMEM16A is essential for these currents in supporting cells. Also, by using extracellular ATP as physiological stimuli, we found that the stimulation of purinergic receptors activates a large TMEM16A-dependent Cl- current, indicating a possible role of TMEM16A in ATP-mediated signaling. Altogether, our results establish that TMEM16A-mediated currents are functional in olfactory supporting cells and provide a foundation for future work investigating the precise physiological role of TMEM16A in the olfactory system

Charged Annular Disks and Reissner-Nordstr\"{o}m Type Black Holes from Extremal Dust

We present the first analytical superposition of a charged black hole with an annular disk of extremal dust. In order to obtain the solutions, we first solve the Einstein-Maxwell field equations for sources that represent disk-like configurations of matter in confomastatic spacetimes by assuming a functional dependence among the metric function, the electric potential and an auxiliary function,which is taken as a solution of the Laplace equation. We then employ the Lord Kelvin Inversion Method applied to models of finite extension in order to obtain annular disks. The structures obtained extend to infinity, but their total masses are finite and all the energy conditions are satisfied. Finally, we observe that the extremal Reissner-Nordstr\"{o}m black hole can be embedded into the center of the disks by adding a boundary term in the inversion.Comment: 17 revtex pages, 8 eps figure

BioPAN: a web-based tool to explore mammalian lipidome metabolic pathways on LIPID MAPS.

Lipidomics increasingly describes the quantification using mass spectrometry of all lipids present in a biological sample.  As the power of lipidomics protocols increase, thousands of lipid molecular species from multiple categories can now be profiled in a single experiment.  Observed changes due to biological differences often encompass large numbers of structurally-related lipids, with these being regulated by enzymes from well-known metabolic pathways.  As lipidomics datasets increase in complexity, the interpretation of their results becomes more challenging.  BioPAN addresses this by enabling the researcher to visualise quantitative lipidomics data in the context of known biosynthetic pathways.  BioPAN provides a list of genes, which could be involved in the activation or suppression of enzymes catalysing lipid metabolism in mammalian tissues