1,976 research outputs found

    Repulsion of an evolving surface on walls with random heights

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    We consider the motion of a discrete random surface interacting by exclusion with a random wall. The heights of the wall at the sites of Zd\Z^d are i.i.d.\ random variables. Fixed the wall configuration, the dynamics is given by the serial harness process which is not allowed to go below the wall. We study the effect of the distribution of the wall heights on the repulsion speed.Comment: 8 page

    Stability of a lyophilized milk enriched with microbial CLA/CLNA

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    Conjugated linoleic (CLA) and conjugated linolenic (CLNA) acids have been described with potential bioactive properties. Due limited availability in their natural sources (e.g. ruminants’ milk and meat or vegetable oils), in situ microbial production in dairy products may potentially improve CLA/CLNA daily intake. Several probiotic strains have been reported to produce CLA/CLNA isomers using linoleic (LA) and alpha-linolenic (α-LNA) acids as precursor substrates, respectively. Previous work by this research team led to the formulation of a CLA/CLNA-enriched lyophilized milk, using Bifidobacterium breve DSM 20091 and hydrolysed flaxseed oil (FSO; rich in α-LNA). Since CLA, CLNA, LA and α-LNA are polyunsaturated and prone to oxidation, this research aimed to investigate if this new functional milk product is stable at conditions mimicking shelf-life. Pasteurized cow milk (100 mL) inoculated with B. breve DSM 20091 and hydrolysed FSO or not (control) was fermented for 22 h at 37 ºC under anaerobic conditions. Afterwards, samples were lyophilized and stored at room temperature in an exicator, being air- and light-protected. Samples were taken at the beginning (T0wk) and every 4 weeks until the end of the assay (T12wk) for further microbial counting and fatty acid (FA) analysis. Concerning to B. breve DSM 20091 viable cell counting, counts remained below the countable range during the entire study, so as total microbial counting. As for FA analysis, in the non-esterified fraction, the CLA and CLNA contents in the enriched milk product increased after 4 weeks (up to 1.80 and 11.12 mg/g, respectively) and, thereafter, no significant differences were detected. The same was observed for total polyunsaturated FA, but, in the esterified fraction, its level increased significantly after 8 weeks (up to 6.01 mg/g) and then reduced to 5.18 mg/g at the end of the study. In conclusion, a lyophilised milk enriched with microbial CLA/CLNA is not entirely stable, including its CLA/CLNA content, which was inclusively enhanced.info:eu-repo/semantics/publishedVersio

    Analytical results for a Bessel function times Legendre polynomials class integrals

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    When treating problems of vector diffraction in electromagnetic theory, the evaluation of the integral involving Bessel and associated Legendre functions is necessary. Here we present the analytical result for this integral that will make unnecessary numerical quadrature techniques or localized approximations. The solution is presented using the properties of the Bessel and associated Legendre functions.Comment: 4 page

    Variabilidade espacial da textura de dois solos do Deserto Salino, no Estado do Rio Grande do Norte.

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    Este trabalho teve como objetivo avaliar a variabilidade espacial da textura do solo, em duas áreas do Deserto Salino, na região da planície aluvial do Rio Apodi/Mossoró-RN. Para atingir esse objetivo, utilizaram-se técnicas de geoestatística. As áreas foram georeferenciadas em imagens de satélite (LandSat TM-7), empregandose um GPS portátil. O esquema de amostragem foi ao acaso com 60 unidades amostrais, com volume de 1 dm3, coletadas na camada de 0 a 5 cm. Com exceção do teor de areia grossa no Vertissolo hidromórfico, todos os demais componentes granulométricos, em ambos os solos, apresentaram dependência espacial, sendo o esférico e o exponencial os modelos ajustados aos semivariogramas. O valor do efeito ?pepita? teve pequena contribuição na variância total dos dados e as variáveis apresentaram forte dependência espacial. Houve grande variação na distância até onde as variáveis estudadas apresentaram dependência espacial (alcance), tanto dentro das áreas como entre as áreas estudadas para a maioria das variáveis, indicando que a utilização de um mesmo esquema de amostragem não é apropriado quando se trabalha com muitas variáveis. Por meio dos mapas de ?krigagem?, identificaram-se padrões semelhantes de distribuição espacial para algumas características físicas em função da dinâmica da água

    Scaling Limit and Critical Exponents for Two-Dimensional Bootstrap Percolation

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    Consider a cellular automaton with state space {0,1}Z2\{0,1 \}^{{\mathbb Z}^2} where the initial configuration ω0\omega_0 is chosen according to a Bernoulli product measure, 1's are stable, and 0's become 1's if they are surrounded by at least three neighboring 1's. In this paper we show that the configuration ωn\omega_n at time n converges exponentially fast to a final configuration ωˉ\bar\omega, and that the limiting measure corresponding to ωˉ\bar\omega is in the universality class of Bernoulli (independent) percolation. More precisely, assuming the existence of the critical exponents β\beta, η\eta, ν\nu and γ\gamma, and of the continuum scaling limit of crossing probabilities for independent site percolation on the close-packed version of Z2{\mathbb Z}^2 (i.e., for independent ∗*-percolation on Z2{\mathbb Z}^2), we prove that the bootstrapped percolation model has the same scaling limit and critical exponents. This type of bootstrap percolation can be seen as a paradigm for a class of cellular automata whose evolution is given, at each time step, by a monotonic and nonessential enhancement.Comment: 15 page
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