641 research outputs found

    OS ESLAVOS NUM CLÁSSICO PORTUGUÊS DO SÉCULO XVII

    Get PDF
    OS ESLAVOS NUM CLÁSSICO PORTUGUÊSDO SÉCULO XVII(Considerações sôbre o que deles dizFr. Manoel dos Anjos na sua "História Universal"

    A CRONOLOGIA DOS EMPRÉSTIMOS

    Get PDF
    A CRONOLOGIA DOS EMPRÉSTIMO

    NOVAS NOTAS AO «GLOSSÁRIO LUSO ASIÀTICO»

    Get PDF
    NOVAS NOTAS AO «GLOSSÁRIOLUSO ASIÀTICO

    Critical behavior of hard-core lattice gases: Wang-Landau sampling with adaptive windows

    Full text link
    Critical properties of lattice gases with nearest-neighbor exclusion are investigated via the adaptive-window Wang-Landau algorithm on the square and simple cubic lattices, for which the model is known to exhibit an Ising-like phase transition. We study the particle density, order parameter, compressibility, Binder cumulant and susceptibility. Our results show that it is possible to estimate critical exponents using Wang-Landau sampling with adaptive windows. Finite-size-scaling analysis leads to results in fair agreement with exact values (in two dimensions) and numerical estimates (in three dimensions).Comment: 20 pages, 11 figure

    Cosmological models with linearly varying deceleration parameter

    Full text link
    We propose a new law for the deceleration parameter that varies linearly with time and covers Berman's law where it is constant. Our law not only allows one to generalize many exact solutions that were obtained assuming constant deceleration parameter, but also gives a better fit with data (from SNIa, BAO and CMB), particularly concerning the late time behavior of the universe. According to our law only the spatially closed and flat universes are allowed; in both cases the cosmological fluid we obtain exhibits quintom like behavior and the universe ends with a big-rip. This is a result consistent with recent cosmological observations.Comment: 12 pages, 7 figures; some typo corrections; to appear in International Journal of Theoretical Physic

    Biochemical parameters of silver catfish (Rhamdia quelen) after transport with eugenol or essential oil of Lippia alba added to the water

    Get PDF
    The transport of live fish is a routine practice in aquaculture and constitutes a considerable source of stress to the animals. The addition of anesthetic to the water used for fish transport can prevent or mitigate the deleterious effects of transport stress. This study investigated the effects of the addition of eugenol (EUG) (1.5 or 3.0 mu L L-1) and essential oil of Lippia alba (EOL) (10 or 20 mu L L-1) on metabolic parameters (glycogen, lactate and total protein levels) in liver and muscle, acetylcholinesterase activity (AChE) in muscle and brain, and the levels of protein carbonyl (PC), thiobarbituric acid reactive substances (TBARS) and nonprotein thiol groups (NPSH) and activity of glutathione-S-transferase in the liver of silver catfish (Rhamdia quelen; Quoy and Gaimard, 1824) transported for four hours in plastic bags (loading density of 169.2 g L-1). The addition of various concentrations of EUG (1.5 or 3.0 mu L L-1) and EOL (10 or 20 mu L L-1) to the transport water is advisable for the transportation of silver catfish, since both concentrations of these substances increased the levels of NPSH antioxidant and decreased the TBARS levels in the liver. In addition, the lower liver levels of glycogen and lactate in these groups and lower AChE activity in the brain (EOL 10 or 20 mu L L-1) compared to the control group indicate that the energetic metabolism and neurotransmission were lower after administration of anesthetics, contributing to the maintenance of homeostasis and sedation status.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Pesquisa e Desenvolvimento Cientifico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); CNPqinfo:eu-repo/semantics/publishedVersio

    Two-dimensional lattice polymers: adaptive windows simulations

    Full text link
    We report a numerical study of self-avoiding polymers on the square lattice, including an attractive potential between nonconsecutive monomers. Using Wang-Landau sampling (WLS) with adaptive windows, we obtain the density of states for chains of up to N=300 monomers and associated thermodynamic quantities. The method enables one to simulate accurately the low-temperature regime, which is virtually inaccessible using traditional methods. Instead of defining fixed energy windows, as in usual WLS, this method uses windows with boundaries that depend on the set of energy values on which the histogram is flat at a given stage of the simulation. Shifting the windows each time the modification factor ff is reduced, we eliminate border effects that arise in simulations using fixed windows.Comment: 8 pages, 5 figure

    Frictional drag between non-equilibrium charged gases

    Full text link
    The frictional drag force between separated but coupled two-dimensional electron gases of different temperatures is studied using the non-equilibrium Green function method based on the separation of center-of-mass and relative dynamics of electrons. As the mechanisms of producing the frictional force we include the direct Coulomb interaction, the interaction mediated via virtual and real TA and LA phonons, optic phonons, plasmons, and TA and LA phonon-electron collective modes. We found that, when the distance between the two electron gases is large, and at intermediate temperature where plasmons and collective modes play the most important role in the frictional drag, the possibility of having a temperature difference between two subsystems modifies greatly the transresistivity.Comment: 8figure

    Characterization and basic guidelines for the quality control of chitosan for drug delivery in pharmaceutical applications

    Get PDF
    Chitosan is increasingly used as an alternative to synthetic polymers due to its water solubility, biodegradability, and biological activity. In this work, chitosan samples from three suppliers were evaluated and characterized by physicochemical methods in an attempt to analyze pharmaceutical applications. The degree of deacetylation (DD) was determined by 1H NMR, IR spectra, potentiometric titration, and UV spectrophotometry. The analysis was supplemented by the techniques of DSC, TG, loss on drying, pH of the suspension, heavy metals, sulphated ash, and triple detector size exclusion chromatography (TriSEC). The use of UV, IR, and 1H NMR techniques to determine the degree of deacetylation, limit testing for heavy metals and sulphated ash to analyze inorganic waste, and TriSEC to analyze molecular weights and molecular distribution are recommended as basic requirements for pharmaceutical applications.Colegio de Farmacéuticos de la Provincia de Buenos Aire
    corecore