6,670 research outputs found

    Dynamic Scaling of Non-Euclidean Interfaces

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    The dynamic scaling of curved interfaces presents features that are strikingly different from those of the planar ones. Spherical surfaces above one dimension are flat because the noise is irrelevant in such cases. Kinetic roughening is thus a one-dimensional phenomenon characterized by a marginal logarithmic amplitude of the fluctuations. Models characterized by a planar dynamical exponent z>1z>1, which include the most common stochastic growth equations, suffer a loss of correlation along the interface, and their dynamics reduce to that of the radial random deposition model in the long time limit. The consequences in several applications are discussed, and we conclude that it is necessary to reexamine some experimental results in which standard scaling analysis was applied

    Alignment tests for low CMB multipoles

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    We investigate the large scale anomalies in the angular distribution of the cosmic microwave background radiation as measured by WMAP using several tests. These tests, based on the multipole vector expansion, measure correlations between the phases of the multipoles as expressed by the directions of the multipole vectors and their associated normal planes. We have computed the probability distribution functions for 46 such tests, for the multipoles l=2-5. We confirm earlier findings that point to a high level of alignment between l=2 (quadrupole) and l=3 (octopole), but with our tests we do not find significant planarity in the octopole. In addition, we have found other possible anomalies in the alignment between the octopole and the l=4 (hexadecupole) components, as well as in the planarity of l=4 and l=5. We introduce the notion of a total likelihood to estimate the relevance of the low-multipoles tests of non-gaussianity. We show that, as a result of these tests, the CMB maps which are most widely used for cosmological analysis lie within the ~ 10% of randomly generated maps with lowest likelihoods.Comment: References added, updated discussion on alignment with Ecliptic Plane. 12 Pages, 6 Figures. Results for additional maps, the normalized frequencies for the tests and a Mathematica Notebook that computes the tests can be found on http://fma.if.usp.br/~abramo/MVA.htm

    Method Description and Demonstration

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    This work was mainly funded by ERC‐CoG‐2014, ChapTherPV, 647596 and partially by H2020‐ICT‐2014‐1, RIA, TransFlexTeg, 645241, FEDER funds through the COMPETE 2020 Program and National Funds through FCT – Portuguese Foundation for Science and Technology with the reference SFRH/BD/135948/2018. Publisher Copyright: © 2020 The Authors. Published by Wiley-VCH GmbH.The reproducibility of chemical synthesis is of crucial importance for both chemical industry and research. The development of simple yet robust methods and algorithms that generate a set of data to help the community access their method's reproducibility is desirable. We report a method for obtaining, processing and analyzing recorded images, using scripting language Python 3, from any camera that allows continuous visualization and recording of a chemical synthesis. The method can be used to assert synthesis reproducibility, to capture reaction events that might elude the naked eye and later be isolated in posterior reactions, to refine synthesis parameters such as temperature, microwave power and time and also to understand chemical reactions during synthesis. The method was exemplified with two microwave-assisted synthesis, zinc sulfide and silver sulfide, processed at our lab and applied to videos from other authors.publishersversionpublishe

    Classical solutions for the Carroll-Field-Jackiw-Proca electrodynamics

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    In the present work, we investigate classical solutions of the Maxwell-Carroll-Field-Jackiw-Proca (MCFJP) electrodynamics for the cases a purely timelike and spacelike Lorentz-violating (LV) background. Starting from the MCFJP Lagrangian and the associated wave equations written for the potential four-vector, the tensor form of the Green function is achieved. In the timelike case, the components of the stationary Green function are explicitly written. The classical solutions for the electric and magnetic field strengths are then evaluated, being observed that the electric sector is not modified by the LV background, keeping the Maxwell-Proca behavior. The magnetic field associated with a charge in uniform motion presents an oscillating behavior that also provides an oscillating MCFJ solution (in the limit of a vanishing Proca mass), but does not recover the Maxwell-Proca solution in the limit of vanishing background. In the spacelike case, the stationary Green function is written and also explicitly carried out in the regime of a small background. The electric and magnetic fields reveal to possess an exponentially decaying behavior, that recover the Maxwell-Proca solutions.Comment: 14 rextex4 pages; 2 figures; minimal changes in abstract and introduction; added reference

    Musical Auditory Stimulation and Cardiac Autonomic Regulation

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    Previous studies have already demonstrated that auditory stimulation with music influences the cardiovascular system. In this study, we described the relationship between musical auditory stimulation and heart rate variability. Searches were performed with the Medline, SciELO, Lilacs and Cochrane databases using the following keywords: “auditory stimulation”, “autonomic nervous system”, “music” and “heart rate variability”. The selected studies indicated that there is a strong correlation between noise intensity and vagal-sympathetic balance. Additionally, it was reported that music therapy improved heart rate variability in anthracycline-treated breast cancer patients. It was hypothesized that dopamine release in the striatal system induced by pleasurable songs is involved in cardiac autonomic regulation. Musical auditory stimulation influences heart rate variability through a neural mechanism that is not well understood. Further studies are necessary to develop new therapies to treat cardiovascular disorders

    Assessing the quality of the relation between scalarizing function parameters and solutions in multiobjective optimization

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    Different Multi-Objective Optimization Methods (MOOM) for solving Multi-Objective Optimization Problems (MOOP) have been suggested in the literature. These methods often comprise two stages (not necessarily sequential): i) the search for the Pareto-optimal set and ii) the selection of a single solution from this non-dominated set. Various studies comparing performance of particular aspects of these methods have been carried out. However, a theoretical support that changes on the preferences of a Decision Maker (DM) will be reflected in the same way on the solution of the MOOP given by the MOOM has not been presented. In this work a consistency measure to assess MOOM is proposed. It will used to compare the performance of different methods available in the literature. This study was performed using some benchmark test problems, with two criteria.This work was supported in part by the Portuguese Fundacao para a Ciencia e Tecnologia under grants: PTDC/GES/70168/2006 and SFRH/BD/22808/2005

    Cooperação orientada à produção de conhecimento científico

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    O termo e conceito cooperação tem vindo a ocupar cada vez mais e com maior ênfase os espaços noticiosos e de debate, sustentando a rede de projectos que se sucedem um pouco por todo o planeta, com fim à construção de uma “casa comum” onde, como nas grandes famílias, as aprendizagens matriciais passam pelo “aprender a viver juntos”, “aprender a aprender juntos” e “aprender a crescer juntos”, princípios de globalização planetária

    (Oligo)thienyl-imidazo-benzocrown ether derivatives : synthesis, photophysical studies and evaluation of their chemosensory properties

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    A series of novel (oligo)thienyl-imidazobenzocrown ethers were synthesised through a simple method and evaluated as fluorimetric chemosensors for transition metal cations. Interaction with Ni2+, Pd2+, and Hg2+ in ACN/DMSO solution (99:1) was studied by absorption and emission spectroscopy. Chemoselectivity studies in the presence of Na+ were also carried out and a fluorescence enhancement upon chelation (CHEF) effect was observed following Hg2+ complexation. Considering that most systems using fluorescence spectroscopy for detecting Hg2+ are based on the complexation enhancement of the fluorescence quenching (CHEQ) effect, the present work represents one of the few examples for sensing of Hg2+ based on a CHEF effect.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/QUI/66250/2006, SFRH/BD/36396/2007, SRFH/BPD/72557/201
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