1,426 research outputs found
The geometry of slums: boundaries, packing and diversity
The geometry of squatter settlements on the northeastern coast of Brazil is
examined and compared to settlements in the central region of Kenya. In
particular, fragmented structures, often squatter settlements composed of
islands of dwelling or �habitations� in these settlements, and void areas which
are unoccupied regions between dwellings, are studied. We find that such
settlements, when constrained by urban and natural boundaries, present robust
configurational patterns, which we can express best by statistical distributions
with the scaling properties. Such scaling properties, when considered in the
context of urban planning, can be useful for describing and predicting the
spatial and social parameters of such squatter settlements. Several scaling
functions and other mathematical formulae, which are of interest in planning,
are also derived and discussed
Energy and volume of vector fields on spherical domains
We present in this paper a \boundary version" for theorems about minimality
of volume and energy functionals on a spherical domain of threedimensional
Euclidean sphere
The Immune Response to Sand Fly Salivary Proteins and Its Influence on Leishmania Immunity
Leishmaniasis is a vector-borne disease transmitted by bites of phlebotomine sand flies. During Leishmania transmission, sand fly saliva is co-inoculated with parasites into the skin of the mammalian host. Sand fly saliva consists of roughly thirty different salivary proteins, many with known roles linked to blood feeding facilitation. Apart from the anti-hemostatic capacity of saliva, several sand fly salivary proteins have been shown to be immunogenic. Immunization with a single salivary protein or exposure to uninfected bites was shown to result in a protective immune response against leishmaniasis. Antibodies to saliva were not required for this protection. A strong body of evidence points to the role for saliva-specific T cells producing IFN-γ in the form of a delayed-type hypersensitivity reaction at the bite site as the main protective response. Herein, we review the immunity to sand fly salivary proteins in the context of its vector–parasite–host combinations and their vaccine potential, as well as some recent advances to shed light on the mechanism of how an immune response to sand fly saliva protects against leishmaniasis
Evaluación de la transparencia pasiva en cámaras municipales en Brasil
The goal of this study is to investigate compliance with the requirements of passive transparency in city councils of Brazilian municipalities with populations greater than 300,000 inhabitants. The research is descriptive, operationalized by a survey with predominantly qualitative approach. The data collected from 79 city councils were analyzed using the descriptive analysis technique. Three groups were identified in the city councils analyzed: first, city councils to which it was not possible to submit the request for information; second, city councils to which the request for information was submitted, but there was no reply or the response was insufficient; and third, city councils to which the request for information was submitted and there was satisfactory response. The scenario shows little passive transparency before the technological apparatus was available. There are city councils that violate a series of legal provisions regulating the transparency of government actions. The study stands out for diagnosing the current situation of passive transparency in the city councils of the largest Brazilian municipalities, revealing how the law, in general, can be violated, and not taken seriously.O estudo teve por objetivo investigar o atendimento às exigências de transparência passiva pelas câmaras de municípios brasileiros com população superior a 300.000 habitantes. A pesquisa é descritiva, operacionalizada por um estudo de levantamento, com abordagem predominantemente qualitativa. Os dados coletados com 79 câmaras municipais foram analisados pela técnica da análise descritiva. Identificaram-se três grupos nas câmaras analisadas: o primeiro refere-se às câmaras em que não foi possível encaminhar o requerimento; o segundo diz respeito às câmaras cujo requerimento foi encaminhado, mas não houve retorno (resposta) ou o retorno foi insuficiente; o terceiro considera às câmaras em que o requerimento foi encaminhado e houve retorno satisfatório. É um cenário que revela pouca transparência passiva diante de um aparato tecnológico disponível. Há câmaras que descumprem uma sucessão de textos legais que regulamentam a transparência dos atos governamentais. O estudo se destaca por diagnosticar a atual situação da transparência passiva de câmaras dos maiores municípios brasileiros e revela como a lei, em geral, pode ser descumprida, não levada à sério.El objeto del estudio es analizar la atención a las exigencias de transparencia pasiva por parte de las cámaras de los municipios brasileños con población superior a 300.000 habitantes. Se llevó a cabo el estudio descriptivo por medio de un análisis predominantemente cualitativo. Los datos obtenidos en las 79 cámaras municipales fueron analizados por la técnica de análisis descriptivo. Se identificaron tres grupos en las cámaras estudiadas: el primero se refiere a las cámaras en las que no fue posible tramitar la petición; el segundo se refiere a las cámaras en que se tramitó la petición, pero no hubo respuesta o la misma fue insuficiente, y el tercero considera a las cámaras en las que se tramitó la petición y hubo una respuesta satisfactoria. Es un escenario que indica poca transparencia pasiva delante de la tecnología disponible. Existen cámaras que no cumplen con una sucesión de textos legales que regulan la transparencia de los actos gubernamentales. El estudio se destaca por diagnosticar la situación actual de la transparencia pasiva de las cámaras de los mayores municipios brasileños, y muestra como la ley, en general, puede ser incumplida y no ser plenamente respetada
Análise proteômica de bactérias simbióticas fixadoras de nitrogênio de interesse agronômico
Orientadora : Profª Drª Lygia Vitória Galli-TerasawaCo-orientadora : Drª Mariangela HungriaTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Genética. Defesa: Curitiba, 24/11/2014Inclui referênciasÁrea de concentraçãoResumo: A fixação biológica do nitrogênio (FBN) desempenha um papel fundamental na incorporação do nitrogênio na biosfera, principalmente através da simbiose entre bactérias fixadoras de nitrogênio, comumente denominadas de rizóbios, e plantas leguminosas. Na agricultura, a utilização de bactérias competitivas, tolerantes a condições de estresse e eficientes na fixação do nitrogênio tem promovido redução de custos, aumento da produtividade e benefícios ao meio ambiente, características que fizeram da FBN um dos pilares da sustentabilidade agrícola. Neste contexto, identificar os fatores que conferem tais qualidades a determinadas estirpes de rizóbios é necessário para o melhor entendimento e o aproveitamento do processo simbiótico de fixação do nitrogênio. Com esse objetivo, duas estirpes com elevada eficiência em fixar nitrogênio e capazes de tolerar estresses comuns a regiões tropicais, como altas temperaturas, Rhizobium freirei PRF 81 e Bradyrhizobium diazoefficiens CPAC 7, foram caracterizadas com o auxílio de ferramentas da genômica funcional. R. freirei é simbionte do feijoeiro (Phaseolus vulgaris L.) e B. diazoefficiens da soja (Glycine max (L.) Merr). Através da eletroforese bidimensional (2-DE) seguida da espectrometria de massas foram obtidos os mapas proteômicos, identificando, para cada estirpe, 115 proteínas. Nos dois estudos, as proteínas relacionadas com as atividades metabólicas foram as mais numerosas, refletindo diretamente na elevada competitividade apresentada por essas estirpes. Proteínas importantes para o estabelecimento da simbiose e relacionadas à tolerância a condições de estresse, sobretudo as mais comumente encontradas em regiões tropicais, também foram evidenciadas. Diversas proteínas hipotéticas identificadas no mapa proteômico da estirpe CPAC 7 tiveram suas prováveis funções atribuídas por meio de ferramentas de bioinformática. Outras, com pouca ou nenhuma informação disponível, tiveram a expressão de seus respectivos genes avaliada por PCR quantitativo em tempo real (RT-qPCR) na presença do flavonoide genisteína, um composto liberado pelas raízes das plantas hospedeiras capaz de induzir o estabelecimento da simbiose. Entre os genes analisados, seis apresentaram indução significativa, incluindo o gene para a proteína Blr0227 de B. diazoefficiens, que participa da biossíntese de poli-beta-hidroxibutirato (PHB), um composto que pode estar relacionado com a elevada competitividade apresentada por essa estirpe. Os resultados alcançados com a combinação da análise proteômica, bioinformática e o estudo da expressão de genes para proteínas hipotéticas geraram novas informações sobre as propriedades dos microssimbiontes estudados. Palavras-chave: Rhizobium freirei, Bradyrhizobium diazoefficiens, proteômica, RT-qPCR, estresses ambientais, proteínas hipotéticas.Abstract: Biological nitrogen fixation (BNF) has an outstanding role in the nitrogen incorporation on the biosphere, mainly by the symbiosis between N2-fixing bacteria, which are frequently referred to as rhizobia, and leguminous plants. In agriculture, the use of bacteria highly competitive, tolerant to stressful conditions and efficient in nitrogen fixation contributes to the improvement of food production, to decrease the input costs and to mitigate environmental degradation, features that include BNF as one of the pillars of the sustentability. In this sense, highlighting the factors that confer such qualities to rhizobial strains is required to better understand and maximize the nitrogen fixation process. With this aim, two strains efficient in fixing nitrogen and tolerant to different stressing conditions, Rhizobium freirei PRF 81 and Bradyrhizobium diazoefficiens CPAC 7, were studied by functional genomic tools. R. freirei is a symbiont of common bean (Phaseolus vulgaris L.) and B. diazoefficiens of soybean (Glycine max (L.) Merr.). The proteomic reference maps were obtained by two-dimensional electrophoresis (2-DE) and mass spectrometry, and allowed the identification, for each strain, of 115 proteins. In both strains, proteins related to the metabolism were the most abundant, reflecting the metabolic plasticity showed by these strains. Important determinants to the symbiosis establishment and to the tolerance of adverse conditions, especially those experienced in tropical regions, were also detected. Several hypothetical proteins identified in the CPAC 7 proteomic map had their putative functions attributed by the use of bioinformatics tools. Others, with few or without available information, had their coding-genes analysed by real time quantitative PCR (RT-qPCR) in response to one nodulation-inducing molecule, the flavonoid genistein. Among these genes, six were significantly up-regulated, including the protein codding-gene blr0227 that is envolvet with poly-beta-hydroxybutirate (PHB) biosynthesis, which might be related to the bacteria competitiveness. The results obtained by the combination of proteomics analysis, bioinformatics and gene-expression assays resulted in new information about the microssymbionts properties. Keywords: Rhizobium freirei, Bradyrhizobium diazoefficiens, proteomics, RTqPCR, environmental stress, hypothetical proteins
Semi-compactness and multiple oscillating pulses in kink scattering
In this work we consider model of asymmetric kinks, where the behavior of the
solution in one side is different from the other side. Also, the models depend
of an integer and, with the increase of , the constructed kink assumes a
hybrid character: a compactlike profile on one side and a kinklike profile on
the other side. We investigate numerically the kink-antikink and antikink-kink
dynamics, with the aim to understand the effect of the transition of the usual
kink to the semi-compacton structure. The kink-antikink process shows the
formation of one-bounce windows for small values of . The increase of
favors the breaking this structure and the appearance of oscillatory modes. For
antikink-kink collisions we report the appearance of two-bounce windows for
small values of the parameter. We also found an intricate structure of
two-oscillation windows.Comment: 25 pages, 19 figures. v3: updated to match the published versio
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