26,967 research outputs found

    t-structures for relative D-modules and t-exactness of the de Rham functor

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    This paper is a contribution to the study of relative holonomic D-modules. Contrary to the absolute case, the standard t-structure on holonomic D-modules is not preserved by duality and hence the solution functor is no longer t-exact with respect to the canonical, resp. middle-perverse, t-structure. We provide an explicit description of these dual t-structures. We use this description to prove that the solution functor as well as the relative Riemann-Hilbert functor are t-exact with respect to the dual t-structure and to the middle-perverse one while the de Rham functor is t-exact for the canonical, resp. middle-perverse, t-structure and their duals

    Effects of a large irrigation reservoir on aquatic and riparian plants: a history of survival and loss

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    Dammed rivers have unnatural stream flows, disrupted sediment dynamics, and rearranged geomorphologic settings. Consequently, fluvial biota experiences disturbed functioning in the novel ecosystems. The case study is the large irrigation reservoir Alqueva in Guadiana River, Southern Iberia. The study area was divided into three zones: upstream and downstream of the dam and reservoir. For each zone, species composition and land use and land cover (LULC) were compared before and after the Alqueva Dam implementation. Data consist of aquatic and riparian flora composition obtained from 46 surveys and the area (%) of 12 classes of LULC obtained in 90 riverine sampling units through the analysis of historical and contemporary imagery. There was an overall decrease of several endemic species and on the riparian shrublands and aquatic stands, although di erences in the proportion of functional groups were not significant. Nevertheless, compositional diversity shows a significant decline in the upstream zone while landscape diversity shows an accentuated reduction in the reservoir area and downstream of the dam, which is likely related to the loss of the rocky habitats of the ‘old’ Guadiana River and the homogenization of the riverscape due to the irrigation intensification. The mitigation of these critical changes should be site-specific and should rely on the knowledge of the interactions between surrounding lands, ecological, biogeomorphologic, and hydrological components of the fluvial ecosystemsinfo:eu-repo/semantics/publishedVersio

    O profetismo no Tratado de Iosepho de FĂ­lon de Alexandria

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    Tendo em conta as vårias conotaçÔes dadas aos chamados profetas bíblicos, é feita uma anålise da personagem e feitos de José, filho do patriarca Jacob, segundo a narrativa de Fílon de Alexandria no tratado De Josepho.FCT até Setembro 201

    ΊύσÎčς no Tratado de FĂ­lon de Alexandria De Iosepho

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    Analisam-se as diversas acepçÔes do lema grego fĂșsis, com proposta de lexicografia para o vocĂĄbulo e introdução de uma nova acepção, Ă  luz da sua utilização por FĂ­lon de AlexandriaFCT atĂ© Setembro 201

    Critical dialogues: slow readings of English literary texts

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    The reader will find gathered together in this volume a selection of articles and essays that have been separately published over the past three decades as a result of my teaching practice and research activity. In chronological terms, they span a period from 1985 until May 2008. These texts were chosen because they are considered to be representative of the type of work I usually do in my classes, undoubtedly as a result of my own academic background, based on a deliberate and specific form of approach to literary texts, my own choice of English authors and, lastly, my most recent interest in inter-art studies.Fundação para a CiĂȘncia e a Tecnologi
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