2,299 research outputs found

    Parallel Mean Curvature Surfaces in Symmetric Spaces

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    We present a reduction of codimension theorem for surfaces with parallel mean curvature in symmetric spaces

    The case study of Setúbal, Portugal

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    Green infrastructure is a strategically planned network of natural and semi-natural areas that are designed and managed to deliver a wide range of ecosystem services. It incorporates green and blue spaces and other physical features in terrestrial and marine areas. Despite the increase of green infrastructure planning in several regions of the world, such as Europe and North America, there is still a complexity and diversity associated with the concept of green infrastructure that influences the variance in approaches of green infrastructure planning. This research proposed a multi-criteria method that was organized in four steps for designing a green infrastructure for the municipality of Setúbal (Portugal) that efficiently integrated the ecological and social components in the planning and policymaking processes, as well as green infrastructure planning principles. The results show a green infrastructure that comprised around 91% of the territory of the case study, organized into two systems: the fundamental green infrastructure, which was related to the areas whose ecological interests were more favorable, and the urban green infrastructure, which aimed to enhance and intensify ecological processes in built-up areas. This approach focused on the protection of ecological functions, the preservation of the cultural and natural heritage, and the prevention of risks at a local level; it also followed several green infrastructure planning principles, namely, connectivity, multifunctionality, diversity, integration, and applicability.publishersversionpublishe

    Rac1/WAVE2 and Cdc42/N-WASP Participation in Actin-Dependent Host Cell Invasion by Extracellular Amastigotes of Trypanosoma cruzi

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    This study evaluated the participation of host cell Rho-family GTPases and their effector proteins in the actin-dependent invasion by Trypanosoma cruzi extracellular amastigotes (EAs). We observed that all proteins were recruited and colocalized with actin at EA invasion sites in live or fixed cells. EA internalization was inhibited in cells depleted in Rac1, N-WASP, and WAVE2. Time-lapse experiments with Rac1, N-WASP and WAVE2 depleted cells revealed that EA internalization kinetics is delayed even though no differences were observed in the proportion of EA-induced actin recruitment in these groups. Overexpression of constitutively active constructs of Rac1 and RhoA altered the morphology of actin recruitments to EA invasion sites. Additionally, EA internalization was increased in cells overexpressing CA-Rac1 but inhibited in cells overexpressing CA-RhoA. WT-Cdc42 expression increased EA internalization, but curiously, CA-Cdc42 inhibited it. Altogether, these results corroborate the hypothesis of EA internalization in non-phagocytic cells by a phagocytosis-like mechanism and present Rac1 as the key Rho-family GTPase in this process.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e TecnologicoUniv Fed Sao Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilFAPESP: 2012/21335-8, 2011/51475-3CNPq: 302068/2016-3Web of Scienc

    Biting midges (Diptera: Ceratopogonidae) from an urban forest fragment in Central Amazon (Brazil): Effects of opening areas on abundance, richness, and composition

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    We assessed the immature stages of Ceratopogonidae (Diptera) in artificial containers in an urban forest fragment in Manaus (Brazil), including their behavioral, biological and ecological information. In addition, we evaluated the effects of deforestation in an open and forested area on Ceratopogonidae communities. Immatures were sampled between August 2012 and July 2014 in artificial containers installed in both habitat types. We collected 685 immatures of seven morpho-species of Bezzia Kieffer, Culicoides Latreille, Dasyhelea Kieffer, Forcipomyia Meigen, and Palpomyia Meigen. In the open area, we recorded higher temperature and electrical conductivity values than in the forested area; however, these variables did not differ between seasons. Water volume was higher in open area and in rainy season, while pH was similar in both areas and seasons. Species richness was higher in forested area, but did not differ between seasons. We did not record differences in abundance between areas or seasons. Community composition differed between areas, but not between seasons. We provide the first records of Culicoides (Hoffmania) insignis Lutz and C. (Haematomyidium) quasiparaensis Clastrier in artificial containers from the state of Amazonas. Our results suggest that the preservation of forested areas in Amazonas is fundamental for the maintenance of the life cycle of some species of Ceratopogonidae.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse

    Production of polymer filament-shaped piezoelectric sensors for e-textiles applications

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    This work aims at the development of piezoelectric materials for flexible sensors produced with various geometries, at low cost and high production rates, adequate for the industrial scale. In particular the filament form, appropriate for integration into textiles, is described, but other geometries, such as tape, are also being studied. The filaments are produced by co-extrusion of multiple layers with piezoelectric and electrically conductive polymer composites.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/CTM/108801/200

    Piezoelectric filaments produced by coextrusion

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    Considering the significant interest of both the academic and industrial communities in the fields of i/e-textiles (interactive/electronic textiles), the number of developed applications is far below the expected. This fact is mainly related to the difficulties on the development of production methodologies adequate to industrial scale processes. In this areas the integration of piezoelectric materials, that possess sensing/actuating capabilities, such as poly(vinylidene fluoride), PVDF, and can be processed using conventional processing techniques, is very promising and has encouraged a large number of research works. However, until now, most of the developed production methodologies are difficult to adapt to the industrial scale. This work reports recent developments achieved, in the framework of a research project, on the production of piezoelectric filament by coextrusion of PVDF and electrical conductive layers. The developed production methodology involves a conventional coextrusion line, for which a coextrusion die was designed to produce a multilayer filament. This filament comprises an inner layer of an electrically conductive Polypropylene grade and a middle layer of PVDF and is coated with an electrical conductive ink. The piezoelectric response of the produced filaments will be also presentedFundação para a Ciência e a Tecnologia (FCT)- FCT PTDC/CTM/108801/200

    Condicionantes geomorfológicos dos deslizamentos nas encostas : avaliação de metodologias e aplicação de modelo de previsão de áreas susceptíveis

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    Deslizamentos são episódios de extrema importância, resultantes da atuação de processos geomorfológicos nas mais diversas escalas temporais causando, em geral, enormes prejuízos à sociedade. Dentre os diversos fatores condicionantes destacam-se os parâmetros morfológicos do terreno, os quais controlam diretamente o equilíbrio das forças e, indiretamente, a dinâmica hidrológica dos solos. Embora muitos estudos tenham voltado a atenção para a descrição de eventos e para o monitoramento de campo, pouco ainda se sabe sobre a previsão de ocorrência destes fenômenos. Acredita-se aqui que a combinação de mapeamentos e monitoramentos de campo, através de modelos matemáticos baseados em processos, tenha muito a contribuir nessa direção. Neste sentido, diversos estudos de campo vêm sendo realizados nas bacias dos rios Quitite e Papagaio no sentido de caracterizar o papel desempenhado pelos diversos parâmetros topográficos no condicionamento dos deslizamentos ali ocorridos em 1996. A partir do modelo digital de terreno das bacias, com uma resolução de 4m2, combinado com vários mapeamentos ali realizados, foi definido o potencial de deslizamento para as diversas classes de cada atributo topográfico. Paralelamente, foram realizados ensaios de campo com o permeâmetro de Guelph e simulações com o modelo matemático SHALSTAB, voltado para a previsão de áreas instáveis, de modo a englobar os mais diferentes cenários. Os resultados atestam o importante papel desempenhado pelos parâmetros topográficos forma da encosta e área de contribuição, geralmente desprezados pelas metodologias de previsão de áreas susceptíveis a deslizamentos. ______________________________________________________________________________ ABSTRACTLandslides are important geomorphological processes, acting along different temporal scales and generally causing huge problems to society. Between the different controlling factors an important role is played by the morphological parameters which directly affect the equilibrium between the forces and indirectly control hillslope hydrology. Although many studies have focused on the description of previous events and field monitoring, little is known about landslide prediction, defining where and when these processes will happen in the near future. It is believed that the combination of field mapping and monitoring with process-based mathematical models is an important tool to landslide investigation. A variety of studies have been carried out in Quitite and Papagaio river basins in order to investigate the role played by the topographic parameters in the landslides triggered by 1996 intense rainstorms. Based on the digital terrain model of the basins, with a 4m2 resolution, together with the different maps obtained, a landslide potential index for the many classes of each topographic attribute was defined. At the same time, field experiments with the Guelph permeameter were carried out and a variety of scenarios were simulated with the SHALSTAB model, a mathematical model for the topographic control on shallow landslides. The results attest the important role played by the topographic parameters hillslope form and contribution area on landsliding in the studied area. However, these topographic attributes are not considered by most of the procedures used to predict landslide generatio
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