777 research outputs found

    Inventário De Moluscos Do Estuário Do Rio Paraíba No Nordeste Do Brasil

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    Coastal ecosystems of northeastern Brazil have important biodiversity with regard to marine mollusks, which are insufficiently studied. Here we provide an inventory of mollusks from two sites in the estuary of the Paraíba River. Mollusks were collected in 2014 and 2016 on the coast and sandbanks located on the properties of Treze de Maio and Costinha de Santo Antônio. The malacofaunal survey identified 12 families, 20 genera and 21 species of bivalves, 17 families, 19 genera and 20 species of gastropods and one species of cephalopod. Bivalves of the family Veneridae Rafinesque, 1815 were the most representative, with a total of five species. Gastropods of the family Littorinidae Children, 1834 had the greatest species richness. The most abundant species were: Neritina virginea (Linnaeus, 1758), Brachidontes exustus (Linnaeus, 1758), Crassostrea brasiliana (Lamarck, 1819), Cerithium atratum (Born, 1778), Anomalocardia brasiliana (Gmelin, 1791), Parvanachis obesa (C. B. Adams, 1845), Phrontis polygonata (Lamarck, 1822), Littoraria angulifera (Lamarck, 1822), L. flava (King, 1832), Tagelus plebeius (Lightfoot, 1786), Echinolittorina lineolata (d’Orbigny, 1840) and Iphigenia brasiliensis (Lamarck, 1818). The results show that the study area has considerable species richness of Mollusca, requiring environmental monitoring in the region mainly due to the economic importance of some species to the local population. © 2017, Universidade Estadual de Campinas UNICAMP. All rights reserved.17

    Nonextensivity in Geological Faults?

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    Geological fault systems, as the San Andreas fault (SAF) in USA, constitute typical examples of self-organizing systems in nature. In this paper, we have considered some geophysical properties of the SAF system to test the viability of the nonextensive models for earthquakes developed in [Phys. Rev. E {\bf 73}, 026102, 2006]. To this end, we have used 6188 earthquakes events ranging in the magnitude interval 2<m<82 < m < 8 that were taken from the Network Earthquake International Center catalogs (NEIC, 2004-2006) and the Bulletin of the International Seismological Centre (ISC, 1964-2003). For values of the Tsallis nonextensive parameter q1.68q \simeq 1.68, it is shown that the energy distribution function deduced in above reference provides an excellent fit to the NEIC and ISC SAF data.Comment: 9 pages, 1 figure, standard LaTeX fil

    Reconstruction of field theory from excitation spectra of defects

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    We show how to reconstruct a field theory from the spectrum of bound states on a topological defect. We apply our recipe to the case of kinks in 1+1 dimensions with one or two bound states. Our recipe successfully yields the sine-Gordon and λϕ4\lambda \phi^4 field theories when suitable bound state spectra are assumed. The recipe can also be used to globally reconstruct the inflaton potential of inflationary cosmology if the inflaton produces a topological defect. We discuss how defects can provide ``smoking gun'' evidence for a class of inflationary models.Comment: 10 pages, 4 figures. Included proof (Appendix B) that wall fluctuation potentials have supersymmetric form. Added reference

    Halistanol sulfate A and rodriguesines A and B are antimicrobial and antibiofilm agents against the cariogenic bacterium Streptococcus mutans

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    AbstractIn the present investigation we report the antibacterial activity of halistanol sulfate A isolated from the sponge Petromica ciocalyptoides, as well as of rodriguesines A and B isolated from the ascidian Didemnum sp., against the caries etiologic agent Streptococcus mutans. The transcription levels of S. mutans virulence genes gtfB, gtfC and gbpB, as well as of housekeeping genes groEL and 16S, were evaluated by sqRT-PCR analysis of S. mutans planktonic cells. There were no alterations in the expression levels of groEL and 16S after antimicrobial treatment with halistanol sulfate A and with rodriguesines A and B, but the expression of the genes gtfB, gtfC and gbpB was down-regulated. Halistanol sulfate A displayed the most potent antimicrobial effect against S. mutans, with inhibition of biofilm formation and reduction of biofilm-associated gene expression in planktonic cells. Halistanol sulfate A also inhibited the initial oral bacteria colonizers, such as Streptococcus sanguinis, but at much higher concentrations. The results obtained indicate that halistanol sulfate A may be considered a potential scaffold for drug development in Streptococcus mutans antibiofilm therapy, the main etiologic agent of human dental caries

    Impactos Nutricionais E Produção De Pimentão Submetido à Deficiência Hídrica

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The sweet pepper is a solanaceous plant of American origin with large consumption in Brazil. In order to study the effects of water stress on the sweet pepper crop, an experiment was conducted in greenhouse. The treatments consisted of soil water content (100%, 85%, 70% and 55% of moisture in the soil field capacity) in a randomized block design with 6 replicates where the experimental units consisted of 16 plants. During the experiment (47, 62, 77 and 92 days after planting) levels of macronutrients (N, P, K, Ca, Mg and S) and micronutrients (B, Cu, Fe, Mn and Zn) present in each plant fraction and the dry mass of plants for the accumulation of these determination were determined. At harvest the number, width and length of fruits from each plant were obtained. Variables were subjected to Tukey test at 5% probability. The water content in the soil interfered significantly with productive variables. To the accumulation of nutrients in the dry matter (leaf + stem) the elements with higher absorption are ordered as follows: K> N> Ca> Mg> S> P and Fe>Mn> Zn> B> Cu. © 2016, Universidade Estadual Paulista - UNESP. All rights reserved.214724735CNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Antimicrobial Activity of the Extract of Stem Bark of Diplotropis Ferruginea Benth

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    This is the first report about the antibacterial activity of Diplotropis ferruginea Benth. In this study, the ethanol extract of D. ferruginea was tested for its antimicrobial activity against strains gram-positive and gram-negative. In order to determine the minimal inhibitory concentration, assays were carried out by micro dilution method. The extract was screened for antimicrobial activity, and it showed antibacterial activity against Escherichia coli and Pseudomonas aeruginosa

    About Bianchi I with VSL

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    In this paper we study how to attack, through different techniques, a perfect fluid Bianchi I model with variable G,c and Lambda, but taking into account the effects of a cc-variable into the curvature tensor. We study the model under the assumption,div(T)=0. These tactics are: Lie groups method (LM), imposing a particular symmetry, self-similarity (SS), matter collineations (MC) and kinematical self-similarity (KSS). We compare both tactics since they are quite similar (symmetry principles). We arrive to the conclusion that the LM is too restrictive and brings us to get only the flat FRW solution. The SS, MC and KSS approaches bring us to obtain all the quantities depending on \int c(t)dt. Therefore, in order to study their behavior we impose some physical restrictions like for example the condition q<0 (accelerating universe). In this way we find that cc is a growing time function and Lambda is a decreasing time function whose sing depends on the equation of state, w, while the exponents of the scale factor must satisfy the conditions i=13αi=1\sum_{i=1}^{3}\alpha_{i}=1 and i=13αi2<1,\sum_{i=1}^{3}\alpha_{i}^{2}<1, ω\forall\omega, i.e. for all equation of state,, relaxing in this way the Kasner conditions. The behavior of GG depends on two parameters, the equation of state ω\omega and ϵ,\epsilon, a parameter that controls the behavior of c(t),c(t), therefore GG may be growing or decreasing.We also show that through the Lie method, there is no difference between to study the field equations under the assumption of a cc-var affecting to the curvature tensor which the other one where it is not considered such effects.Nevertheless, it is essential to consider such effects in the cases studied under the SS, MC, and KSS hypotheses.Comment: 29 pages, Revtex4, Accepted for publication in Astrophysics & Space Scienc

    Impactos ambientais do manejo agroecológico da caatinga no Rio Grande do Norte.

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    O objetivo deste trabalho foi avaliar os impactos ambientais do manejo agroecológico da caatinga, em unidades de produção familiar no Rio Grande do Norte, pelo método Ambitec de produção animal - dimensão ambiental, desenvolvido pela Embrapa Meio Ambiente. Foram avaliadas sete unidades de produção familiar, em quatro projetos de assentamentos de reforma agrária do Município de Apodi, RN. Os dados para o levantamento foram obtidos por meio de questionários aplicados aos representantes das unidades produtivas familiares, que atribuíram, a cada variável estudada, um valor que representou a alteração proporcionada pela implementação da tecnologia. Após a inserção dos coeficientes de alteração de cada variável dos indicadores por unidade de produção, o coeficiente de impacto foi automaticamente calculado por meio da planilha Ambitec. O manejo agroecológico da caatinga resultou num impacto ambiental positivo, e suas maiores contribuições foram relacionadas aos efeitos positivos dos seguintes indicadores: capacidade produtiva do solo, uso de insumos materiais, qualidade do produto e diminuição da emissão de poluentes à atmosfera. Dois indicadores geraram efeitos negativos: o uso de energia e o uso de recursos naturais. Pela superioridade dos benefícios gerados, o manejo agroecológico da caatinga é uma inovação tecnológica geradora de impactos ambientais positivos

    Enhancement of the upper critical field by nonmagnetic impurities in dirty two-gap superconductors

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    Quasiclassic Uzadel equations for two-band superconductors in the dirty limit with the account of both intraband and interband scattering by nonmagnetic impurities are derived for any anisotropic Fermi surface. From these equations the Ginzburg-Landau equations, and the critical temperature TcT_c are obtained. An equation for the upper critical field, which determines both the temperature dependence of Hc2(T)H_{c2}(T) and the orientational dependence of Hc2(θ)H_{c2}(\theta) as a function of the angle θ\theta between H{\bf H} and the c-axis is obtained. It is shown that the shape of the Hc2(T)H_{c2}(T) curve essentially depends on the ratio of the intraband electron diffusivities D1D_1 and D1D_1, and can be very different from the standard one-gap dirty limit theory. In particular, the value Hc2(0)H_{c2}(0) can considerably exceed 0.7TcdHc2/dTc0.7T_cdH_{c2}/dT_c, which can have important consequences for applications of MgB2MgB_2. A scaling relation is proposed which enables one to obtain the angular dependence of Hc2(θ)H_{c2}(\theta) from the equation for Hc2H_{c2} at Hc{\bf H}\| c. It is shown that, depending on the relation between D1D_1 and D2D_2, the ratio of the upper critical field Hc2/Hc2H_{c2}^\|/H_{c2}^\perp for Hab{\bf H}\| ab and Hab{\bf H}\perp ab can both increase and decrease as the temperature decreases. Implications of the obtained results for MgB2MgB_2 are discussed

    Species richness and functional structure of fish assemblages in three freshwater habitats:effects of environmental factors and management

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    In this study, the inverted trophic hypothesis was tested in the freshwater fish communities of a reservoir. The distribution of fish species in three freshwater habitats in the Jurumirim Reservoir, Brazil, was examined using both species richness and the relative proportions of different trophic groups. These groups were used as a proxy for functional structure in an attempt to test the ability of these measures to assess fish diversity. Assemblage structures were first described using non‐metric multidimensional scaling (NMDS). The influence of environmental conditions for multiple fish assemblage response variables (richness, total abundance and abundance per trophic group) was tested using generalised linear mixed models (GLMM). The metric typically employed to describe diversity; that is, species richness, was not related to environmental conditions. However, absolute species abundance was relatively well explained with up to 54% of the variation in the observed data accounted for. Differences in the dominance of trophic groups were most apparent in response to the presence of introduced fish species: the iliophagous and piscivorous trophic groups were positively associated, while detritivores and herbivores were negatively associated, with the alien species. This suggests that monitoring functional diversity might be more valuable than species diversity for assessing effects of disturbances and managements policies on the fish community
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