3,002 research outputs found

    Rodlet cells changes in Oreochromis niloticus in response to organophosphate pesticide and their relevance as stress biomarker in teleost fishes

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    Rodlet cells are frequently found in teleost fishes and although their role in organisms is not completely understood. The occurrence of these cells are related to stress and may undergo changes in contaminated environments, thereby allowing their use as biomarkers. This hypothesis is tested in the present study. Thirty specimens of Oreochromis niloticus were divided into three groups, two groups were exposed to organophosphate pesticide methyl parathion at nominal concentrations of 4 mgl-1 and 8 mgl-1 and one group was kept as control. After ten days, the gills were removed for microscopic study and the number and area of the rodlet cells were analyzed and compared with a well-established method of assessing histological damages in fishes. No significant differences were found in the area of the cells, but there were significant differences in the number of rodlet cells among examined concentrations. The present study provides evidence for the use of this new biomarker in teleost fishes and discusses some of the potential confounding factors of this approach

    The proximal point method for locally lipschitz functions in multiobjective optimization with application to the compromise problem

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    This paper studies the constrained multiobjective optimization problem of finding Pareto critical points of vector-valued functions. The proximal point method considered by Bonnel, Iusem, and Svaiter [SIAM J. Optim., 15 (2005), pp. 953–970] is extended to locally Lipschitz functions in the finite dimensional multiobjective setting. To this end, a new (scalarization-free) approach for convergence analysis of the method is proposed where the first-order optimality condition of the scalarized problem is replaced by a necessary condition for weak Pareto points of a multiobjective problem. As a consequence, this has allowed us to consider the method without any assumption of convexity over the constraint sets that determine the vectorial improvement steps. This is very important for applications; for example, to extend to a dynamic setting the famous compromise problem in management sciences and game theory.Fundação de Amparo à Pesquisa do Estado de GoiásConselho Nacional de Desenvolvimento Científico e TecnológicoCoordenação de Aperfeiçoamento de Pessoal de Nivel SuperiorMinisterio de Economía y CompetitividadAgence nationale de la recherch

    Proyecto Movie – Una experiencia con el tiempo

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    En este artículo se busca explicitar algunas distintas relaciones conceptuales en la percepción del tiempo centrada en el trabajo de rehacer una forestación de un lugar, durante ocho años consecutivos. El proyecto MOVIE, más allá de ser una contracción de estos ocho años de recuperación paisajístico, concentrados en ocho minutos de videos, es también, la motivación experimental donde si imparte toda una posibilidad de análisis textual que ilusiona presentar el concepto de tiempo centrado en la capacidad de recepción y entendimiento de cada sujeto. Las consecuencias imaginativas de intercambio entre el hombre y la naturaleza, sometidos a la acción del tiempo, es el objeto de proyecto. La actividad fotográfica se desarrolla en la finca Taruman ubicada en el Estado Espírito Santo (provincia autónoma), Brasil, desde el 2008, la cual participa como soporte cartográfico, temporal y material de este acto de recuperación ambiental. Se señala que la distinción entre las nociones de tiempo que cambian en los entrelazamientos entre los referentes humanos, paisajísticos, geológicos y de la flora tropical, aparecen también, como resultado de este reto hermenéutico sobre la experiencia entre arte y naturaleza

    Taxonomy Of Aspidosperma Mart. (apocynaceae, Rauvolfioideae) In The State Of Para, Northern Brazil

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Aspidosperma Mart. is one of the most important genera from Apocynaceae Juss. occurring in Brazil. It is present in many plant formations and has species with both medicinal and economic value. From a taxonomic point of view, many of its species are difficult to identify, especially those occurring in the Amazonian region. In order to complement the information already available with regard to the taxonomy and distribution of the genus, the goal of this work was to provide a taxonomic study of the Aspidosperma species occurring in the state of Para, northern Brazil. This study was based on the analysis of vouchers from the BHCB, HBRA, IAC, IAN, INPA, MG, R, RB and UEC herbaria, as well as scanned images of vouchers from Brazilian and foreign herbaria, and specimens collected in the field. Species identification was confirmed by analysis of protologues and types (or images). We present taxonomic descriptions, illustrations and one identification key for the 20 species of Aspidosperma found in Para, with the Baixo Amazonas Mesoregion presenting the largest number of species (17), and the Metropolitana de Belem Mesoregion presenting the Smallest number of species (3). Aspidosperma eteanum, A. oblongum, A. salgadense (endemic of Para) and A. sandwithianum are accepted as species here. Aspidosperma cuspa is a new record for Para. The fruits of Aspidosperma eteanum and A. salgadense, and the seeds of A. eteanum, have been described and illustrated for the first time.162Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, Office for the Advancement of Higher Education)PNADB [PNADB 922/2010]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
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