Vortices in U(1) Noncommutative Gauge Fields

Charged vortex solutions for noncommutative Maxwell-Higgs model in 3+1 dimensions are found. We show that the stability of these vortex solutions is spoiled out for some, large enough, noncommutativity parameter. A non topological charge, however, is induced by noncommutative effects.Comment: references added, slight modifications in the introduction and conclusions. To be published in PR

Chemically tagging the Hyades Supercluster: A homogeneous sample of F6-K4 kinematically selected northern stars

Stellar kinematic groups are kinematical coherent groups of stars that might have a common origin. These groups are dispersed throughout the Galaxy over time by the tidal effects of both Galactic rotation and disc heating, although their chemical content remains unchanged. The aim of chemical tagging is to establish that the abundances of every element in the analysis are homogeneus among the members. We study the case of the Hyades Supercluster to compile a reliable list of members (FGK stars) based on our chemical tagging analysis. For a total of 61 stars from the Hyades Supercluster, stellar atmospheric parameters (Teff, logg, xi, and [Fe/H]) are determined using our code called StePar, which is based on the sensitivity to the stellar atmospheric parameters of the iron EWs measured in the spectra. We derive the chemical abundances of 20 elements and find that their [X/Fe] ratios are consistent with Galactic abundance trends reported in previous studies. The chemical tagging method is applied with a carefully developed differential abundance analysis of each candidate member of the Hyades Supercluster, using a well-known member of the Hyades cluster as a reference (vB 153). We find that only 28 stars (26 dwarfs and 2 giants) are members, i.e. that 46% of our candidates are members based on the differential abundance analysis. This result confirms that the Hyades Supercluster cannot originate solely from the Hyades cluster.Comment: A&A, in pres

Cellulose - Chitosan Nanocomposites - Evaluation of Physical, Mechanical and Biological Properties

This research describes the preparation of membranes with chitosan (CS) as the polymeric matrix and cellulose nanocrystals (CNC) as reinforcement. The aim was to evaluate their physical, mechanical and biological properties, and to determine their potential for biomedical use. Membranes were prepared via casting CNC suspensions in CS solution, at CNC concentrations of 0.5%, 1.0% and 2.0% (w/w) with pure chitosan as a reference. Analysis of membrane properties was performed using several techniques, such as ATR – FTIR, SEM, swelling test, maximum water absorption, dynamical mechanical analysis and in vivo (Winstar rats) biocompatibility and biodegradability assays for biological evaluation. Experimental results established that CNC reduced swelling rates and increased the maximum water absorption when CNC concentration was higher. Therefore, the presence of CNC in the matrix reduced Young’s modulus by approximately 50% in comparison with pure chitosan. All formulations demonstrated biocompatibility and biodegradability values ranged between 4% and 21% in the 30 days after implantation. Based on these results, these membranes may be of use for biomedical applications

Investigation of cell adhesion in chitosan membranes for peripheral nerve regeneration

Peripheral nerve injuries have produced major concerns in regenerative medicine for several years, as the recovery of normal nerve function continues to be a significant clinical challenge. Chitosan (CHT), because of its good biocompatibility, biodegradability and physicochemical properties, has been widely used as a biomaterial in tissue engineering scaffolding. In this study, CHT membranes were produced with three different Degrees of Acetylation (DA), envisioning its application in peripheral nerve regeneration. The three CHT membranes (DA I: 1%, DA II: 2%, DA III: 5%) were extensively characterized and were found to have a smooth and flat surface, with DA III membrane having slightly higher roughness and surface energy. All the membranes presented suitable mechanical properties and did not show any signs of calcification after SBF test. Biodegradability was similar for all samples, and adequate to physically support neurite outgrowth. The in vitro cell culture results indicate selective cell adhesion. The CHT membranes favoured Schwann cells invasion and proliferation, with a display of appropriate cytoskeletal morphology. At the same time they presented low fibroblast infiltration. This fact may be greatly beneficial for the prevention of fibrotic tissue formation, a common phenomenon impairing peripheral nerve regeneration. The great deal of results obtained during this work permitted to select the formulation with the greatest potential for further biological tests.This work has received funding from the European Community's Seventh Framework Programme (FP7-HEALTH-2011) under grant agreement no 278612 (BIOHYBRID). This study was also funded by European Union's FP7 Programme under grant agreement no REGPOT-CT2012-316331-POLARIS.The authors thank the chitosan raw material provided by Altakitin S.A., (Lisboa, Portugal). We are further thankful to Silke Fischer, Natascha Heidrich, Kerstin Kuhlemann, Jennifer Metzen, Hildegard Streich and Maike Wesemann (all from the Institute of Neuroanatomy, Hannover Medical School) for their technical support

La productividad del crédito en las pequeñas y medianas industrias (pymi) del sector manufacturero

The sustainability of productivity growth in an economy is not only generated by the utilization level of production factors - capital and labor - but also by the efficiency increase in the use and combination of these factors. In this sense, this research analyzes credit productivity in SMI in the manufacturing sector of the state of Yaracuy, in order to demonstrate the efficiency of credit use by industries’ owners or managers and its relationship with searching of productivity, through the factors profitability in final goods. This is a field design descriptive study, which addressed nine industries in the footwear, textiles, clothing and metallurgical sectors. Relevant conclusion shows that the desired productivity was not generated by the granted financing, according with the production indicators and employment generation, due to the country's economic environment and administrative barriers that significantly affected the industrial sector.La sostenibilidad del crecimiento de la productividad en una economía, no sólo se genera por el nivel de utilización de los factores de producción - capital y trabajo - sino también por el incremento en la eficiencia con la que se utilizan y combinan estos factores. En este sentido, la presente investigación analiza la productividad del crédito en las PYMI del sector Manufacturero del estado Yaracuy, con el propósito de demostrar la utilización eficiente de los créditos por parte de los dueños/gerentes de las industrias y su relación en la búsqueda de la productividad, por medio del aprovechamiento de los factores utilizados en la producción de bienes finales. El estudio es descriptivo bajo un diseño de campo, en el cual se abordó nueve industrias en áreas del calzado, textil, ropa y metalúrgico. Entre las conclusiones relevantes está que los indicadores de producción y generación de empleo con respecto al financiamiento otorgado, no generaron la productividad deseada, debido a coyunturas económicas propias del país y barreras administrativas que afectaron de manera significativa al sector industri

Human ISWI complexes are targeted by SMARCA5 ATPase and SLIDE domains to help resolve lesion-stalled transcription

Chromatin compaction of deoxyribonucleic acid (DNA) presents a major challenge to the detection and removal of DNA damage. Helix-distorting DNA lesions that block transcription are specifically repaired by transcription-coupled nucleotide excision repair, which is initiated by binding of the CSB protein to lesion-stalled RNA polymerase II. Using live cell imaging, we identify a novel

CONDICIONES ÓPTIMAS PARA OXIDAR FENOL EN AGUA VÍA LOS PROCESOS FENTON Y FOTO-FENTON

Phenol can be degraded to almost 100 % within a few minutes via Fenton and photo-Fenton processes. Its degradation and the ratio of initial molar concentrations of oxidant and catalyst increase in inverse senses, and a ratio of 38.4 was optimal for aqueous solutions contaminated with 20 ppm of phenol. In addition to this, the use of ultraviolet-A light enhanced degradation when compared to shorter wavelengths.Fenol puede ser degradado a casi 100 % en pocos minutos vía los procesos Fenton y fotoFenton. Su degradación y la relación entre las concentraciones molares iniciales de oxidante y catalizador utilizadas aumentan en sentidos inversos, y una relación de 38,4 fue óptima para soluciones acuosas contaminadas con 20 ppm de fenol. Asimismo, el uso de luz ultravioleta del tipo A aumentó la degradación comparado a menores longitudes de onda

Pair contact process with a particle source

We study the phase diagram and critical behavior of the one-dimensional pair contact process (PCP) with a particle source using cluster approximations and extensive simulations. The source creates isolated particles only, not pairs, and so couples not to the order parameter (the pair density) but to a non-ordering field, whose state influences the evolution of the order parameter. While the critical point p_c shows a singular dependence on the source intensity, the critical exponents appear to be unaffected by the presence of the source, except possibly for a small change in beta. In the course of our study we obtain high-precision values for the critical exponents of the standard PCP, confirming directed-percolation-like scaling.Comment: 15 pages, 9 figure

Compósitos de colagénio/apatite de origem marinha para aplicação em engenharia de tecidos mineralizados

Devido ao aumento de lesões associadas ao envelhecimento da população, a regeneração do tecido ósseo tem sido alvo de estudo. Apesar da vasta investigação neste sentido, os auto-enxertos continuam a prevalecer como tratamento de primeira linha, apesar das suas limitações. A extração de compostos de recursos marinhos para uso em abordagens de engenharia de tecidos emerge como uma alternativa promissora para regeneração de lesões ósseas. Neste capítulo apresenta-se um biomaterial promissor para aplicação em engenharia de tecidos duros tendo como base uma estratégia de valorização de sub-produtos marinhos, nomeadamente pele e dentes de tubarão.Os autores agradecem o apoio financeiro recebido da União Europeia através do Programa INTERREG—POCTEP, no âmbito dos Projetos 0687_NOVOMAR_1_P e 0245_IBEROS_1_E, através do Programa de cooperação transnacional Espaço Atlântico, no âmbito do Projeto MARMED (2011-1/164) e através do 7º Programa-Quadro de Investigação e Desenvolvimento Tecnológico (FP7), através do Projeto POLARIS (REGPOT-CT2012-316331). Os autores gostariam de agradecer também ao Centro Tecnológico del Mar (CETMAR, Vigo, Espanha) e COPEMAR SA (Espanha) pelo fornecimento dos subprodutos de tubarão. G.S.D agradece ao Programa Norte2020 (Portugal2020) pela bolsa de doutoramento (NORTE-08-5369-F SE-000044) e R.P. agradece à Fundação para a Ciência e a Tecnologia pelo contrato IF/00347/2015

Grating and interferometric devices in POF

To date, much of the development work associated with polymer optical fibre (POF) applications has been aimed at exploiting the potential of the technology to provide low cost solutions. Here we argue that, in the sensing area at least, POF offers a number of other, more relevant advantages. In this paper we describe work on a range of devices based on photoinscribed gratings and on fibre interferometers, which are designed to take advantage of the unique properties of POF