763 research outputs found

    INTRODUCTION After fourteen years of pioneering systematic work spanning from 1996 to 2010, carried out in the territory of Santa Catarina State, SC, within the Brazilian Southern region, framed in the socalled Atlantic Slope of the Southern Cone of South America (Agudo-Padrón, 2008a), a basic list of continental (land and freshwater) and marine mollusc species was compiled. Besides constant interactions and consultations with numerous national and international specialists, such a list was mostly based on available literature and/or analyses of voucher specimens deposited in collections belonging to research centers or environmental education institutes. To date (up to the first semester of 2010), this list comprises a total of 878 taxa (species and subspecies, including 695 marine and 183 continental forms), and these numbers are likely to increase as field surveys ensue. In the present study, results obtained from the author’s active participation in three recent regional field sampling expeditions dealing with marine and continental mollusc taxa, are reported. I. Official State program for listing and control of invasive exotic species Starting from November 2009, and for the first time in the history of Santa Catarina State, the presence of invasive allochthonous mollusc species in Santa Catarina State was studied and discussed through the organisation of seminars by the Official Foundation for the Environment of the State of Santa Catarina (Fundação do Meio Ambiente – FATMA) jointly with the Hórus Institute for Development and Environmental Conservation (Instituto Hórus de Desenvolvimento e Conservação Ambiental), with the main goal to compile the Official State List of Species. To date, the occurrence of a total of twenty allochthonous (exotic) forms of mollusc species has been confirmed, 14 Gastropoda and 6 Bivalvia [namely, 11 terrestrial gastropods, 5 freshwater taxa (3 gastropods and 2 bivalves) and 4 marine bivalves]. Taking into account the contributions of Agudo & Bleicker (2006a), Agudo-Padrón (2008b) and Agudo-Padrón & Lenhard (2010), the slug Pallifera sp. - the taxonomic determination of which is still in process (Thomé et al., 2006) - was included within such a list. Of these twenty Mollusca and environmental conservation in Santa Catarina State (SC, Southern Brazil): current situation

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    Available knowledge of malacofauna (mollusc species) conservation in the territory of Santa Catarina State,SC, central Southern Brazil region, is shortly analyzed and discussed herein. Present data originate from theauthor's active participation in three recent regional unpublished events dealing with biodiversity conservationin the State, carried out to cope the sensitive lack of population studies which is the main difficulty to face inorder to provide accurate and detailed evaluations on biodiversity and its conservation status

    Current knowledge on population studies on five continental molluscs (Mollusca, Gastropoda et Bivalvia) of Santa Catarina State (SC, Central Southern Brazil region)

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    Although still very scarce, available knowledge on population studies on continental (land and freshwater)molluscs in the territory of Santa Catarina State is shortly analyzed and discussed. Based on the IUCN“Restricted Distribution” criterion, a total of 54 nominal species, including 31 terrestrial gastropods, 15freshwater gastropods and 8 limnic bivalves, were considered strong candidates as threatened taxa. Out of allthese endangered species, only 5 limnic forms (2 gastropods and 3 bivalves) were previously analysed, in someway, at population level

    Un algoritmo de desrefinamiento en 3D para mallas de tetraedros basado en el esqueleto

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    En este trabajo, se presenta un nuevo algoritmo de desrefinamiento para mallas de tetraedros no- estructuradas. El algoritmo es el inverso del algoritmo de refinamiento de Plaza y Carey14. Ambos algoritmos funcionan de forma automática. El algoritmo de refinamiento se puede aplicar a cualquier malla inicial de tetraedros. De igual manera el desrefinamiento se puede usar para conseguir una malla más grosera a partir de una secuencia de mallas encajadas obtenidas por medio de la aplicación reiterada del algoritmo de refinamiento. La combinación de ambos algoritmos se puede usar para resolver problemas dependientes del tiempo en dimensión tres, de forma similar a como ya se han usado algoritmos análogos en dimensiones inferiores Ferragut et al 5.Peer Reviewe

    El anuncio de permuta: nacimiento y desarrollo de una tradición discursiva

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    En este artículo se presenta el anuncio de permutas en Cuba, en su surgimiento como una tradición discursiva que evoluciona desde la inmediatez hacia la distancia. Dado un marco escénico de dos personas con necesidades complementarias de cambio de casa, se analiza la estructura de este discurso, y los recursos con que se logra la seducción o la persuasión. También se estudia la imagen tanto del enunciador como del enunciatario, que se colige del texto. Se evidencia que en este producto comunicativo para el consumo cultural, el mensaje esencial no se refiere a las características del producto transaccional, sino a la voluntad suasoria, y al acto directivo incluido. En la voluntad de crear expectativas y suscitar actitudes, se reproducen creencias y valores; las selecciones léxicas, sintácticas y estructurales muestran y perpetúan el imaginario social que de este dominio tienen los hablantes, de modo que se ofrecen datos para el vínculo entre la historia lingüística externa e interna en Cub

    Reconstruction of osteochondral lesions using carbon fiber

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    Objetivo: Estudiar a largo plazo la evolución histológica de defectos osteocondrales de la rótula de conejos tratados con fibra de carbono. Material y Método: 18 conejos de raza gigante español, variedad parda, de ambos sexos, con un peso aproximado de 1.5 a 2 Kg y 18 discos Cleveland de fibra de carbono de 8 mm de diámetro (Medicarb®, fabricado por Leyland Medical International). Creación de un defecto de 6 mm. de diámetro en la superficie articular de la rótula, hasta alcanzar el tejido óseo subcondral sangrante, que fue rellenado con un disco de fibra de carbono previamente humedecido en solución salina y recortado para una adecuada adaptación al defecto. Resultados: A los seis meses de evolución postoperatoria el defecto fue rellenado por tejido fibroso, a los nueve meses se desarrolló tejido fibrocartilaginoso y a los 12 meses los defectos estaban cubiertos por tejido cartilaginoso hialino. Conclusiones: Demostramos la neoformación de cartílago hialino en defectos osteocondrales de rótula de conejo rellenados con fibra de carbono.Peer Reviewe

    Poisson-Jacobi reduction of homogeneous tensors

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    The notion of homogeneous tensors is discussed. We show that there is a one-to-one correspondence between multivector fields on a manifold MM, homogeneous with respect to a vector field Δ\Delta on MM, and first-order polydifferential operators on a closed submanifold NN of codimension 1 such that Δ\Delta is transversal to NN. This correspondence relates the Schouten-Nijenhuis bracket of multivector fields on MM to the Schouten-Jacobi bracket of first-order polydifferential operators on NN and generalizes the Poissonization of Jacobi manifolds. Actually, it can be viewed as a super-Poissonization. This procedure of passing from a homogeneous multivector field to a first-order polydifferential operator can be also understood as a sort of reduction; in the standard case -- a half of a Poisson reduction. A dual version of the above correspondence yields in particular the correspondence between Δ\Delta-homogeneous symplectic structures on MM and contact structures on NN.Comment: 19 pages, minor corrections, final version to appear in J. Phys. A: Math. Ge
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