117,982 research outputs found
Lie - Backlund symmetries of homogeneous system of bi-dimensional equations
No full textThe framework of generalized (Lie-Backlund) symmetries is used to analyze a general homogeneous hyperbolic system of bi-dimensional quasilinear equations. The symmetries of the first order are constructed and the theorem of the existence of the generalized symmetries is formulated. As example, we consider the spatially one-dimensional time dependent system of equations, which describes the gravity-driven free surface flow of granular avalanches
Lie - Backlund symmetries of homogeneous system of bi-dimensional equations
No full textThe framework of generalized (Lie-Backlund) symmetries is used to analyze a general homogeneous hyperbolic system of bi-dimensional quasilinear equations. The symmetries of the first order are constructed and the theorem of the existence of the generalized symmetries is formulated. As example, we consider the spatially one-dimensional time dependent system of equations, which describes the gravity-driven free surface flow of granular avalanches
EFFECTS OF THE S-ADENOSYLHOMOCYSTEINE HYDROLASE INHIBITORS 3-DEAZAADENOSINE AND 3-DEAZAARISTEROMYCIN ON RNA METHYLATION AND SYNTHESIS
No full textThe effects of 3-deazaaristeromycin and 3-deazaadenosine on RNA methylation and synthesis were examined in the mouse macrophage cell line, RAW264. S-Adenosylhomocysteine accumulated in cells incubated with 3-deazaaristeromycin while S-3-deazaadenosylhomocysteine was the major product in cells incubated with 3-deazaadenosine and homocysteine thiolactone. RNA methylation was inhibited to a similar extent by the accumulation of either S-adenosylhomocysteine or S-3-deazaadenosylhomocysteine, with S-adenosylhomocysteine being a slightly better inhibitor. In mRNA, the synthesis of N6-methyladenosine and N6-methyladenosine and N6-methyl-2'-O-methyladenosine were inhibited to the greatest extent, while the synthesis of 7-methylguanosine and 2'-O-methyl nucleosides were inhibited to a lesser extent. Incubation of cells with 100 μM 3-deazaaristeromycin or with 10 μM 3-deazaadenosine and 50 μM homocysteine thiolactone produced little inhibition of mRNA synthesis, even though mRNA methylation was inhibited. In contrast, mRNA synthesis was greatly inhibited by treatment of cells with 100 μM 3-deazaadenosine and the inhibition of synthesis was not correlated with an inhibition of methylation
Backlund transformation for integrable hierarchies: example - mKdV hierarchy
No full textIn this note we present explicitly the construction of the mKdV hierarchy and show that it decomposes into positive and negative graded sub-hierarchies. We extend the construction of the Backlund transformation for the sinh-Gordon model to all other positive and negative odd graded equations of motion generated by the same affine algebraic structure. Some simple examples of solutions are explicitly verified to satisfy, in a universal manner, the Backlund transformations for the first few odd (positive and negative) sub-hierarchies.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Estadual Paulista, Instituto de Física Teórica, São Paulo, BrasilUniversidade Estadual Paulista, Instituto de Física Teórica, São Paulo, Brasi
Permutability of Backlund transformations for N=2 supersymmetric sine-Gordon
No full textThe permutability of two Backlund transformations is employed to construct a nonlinear superposition formula and to generate a class of solutions for the N=2 super sine-Gordon model. We present explicitly the one and two soliton solutions.Univ Estadual Paulista, Inst Fis Teor, BR-01156970 São Paulo, BrazilUniv Estadual Paulista, Inst Fis Teor, BR-01156970 São Paulo, Brazi
Permutability of Backlund transformation for N=1 supersymmetric sinh-Gordon
No full textThe permutability of two Backlund transformations is employed to construct a nonlinear superposition formula to generate a class of solutions for the N = 1 super sinh-Gordon model. (C) 2009 Elsevier B.V. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Estadual Paulista, Inst Fis Teor, BR-01405900 São Paulo, BrazilUniv Estadual Paulista, Inst Fis Teor, BR-01405900 São Paulo, Brazi
Extracellular vesicles from symbiotic vaginal lactobacilli inhibit HIV-1 infection of human tissues
No full textThe vaginal microbiota, dominated by Lactobacillus spp., plays a key role in preventing HIV-1 transmission. Here, we investigate whether the anti-HIV effect of lactobacilli is mediated by extracellular vesicles (EVs) released by these bacteria. Human cervico-vaginal and tonsillar tissues ex vivo, and cell lines were infected with HIV-1 and treated with EVs released by lactobacilli isolated from vaginas of healthy women. EVs released by L. crispatus BC3 and L. gasseri BC12 protect tissues ex vivo and isolated cells from HIV-1 infection. This protection is associated with a decrease of viral attachment to target cells and viral entry due to diminished exposure of Env that mediates virus-cell interactions. Inhibition of HIV-1 infection is associated with the presence in EVs of several proteins and metabolites. Our findings demonstrate that the protective effect of Lactobacillus against HIV-1 is, in part, mediated by EVs released by these symbiotic bacteria. If confirmed in vivo, this finding may lead to new strategies to prevent male-to-female sexual HIV-1 transmission
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
- …
