9 resultados para informative characters

em Universidade dos Açores - Portugal


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Dissertação de Mestrado, Ambiente, Saúde e Segurança, 19 de Julho de 2013, Universidade dos Açores.

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Tese de Doutoramento, Educação (Desenvolvimento Curricular), 9 de Dezembro de 2013, Universidade dos Açores.

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Mestrado (PES II), Educação Pré-Escolar e Ensino do 1º Ciclo do Ensino Básico, 3 de Julho de 2014, Universidade dos Açores.

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The species abundance distribution (SAD) has been a central focus of community ecology for over fifty years, and is currently the subject of widespread renewed interest. The gambin model has recently been proposed as a model that provides a superior fit to commonly preferred SAD models. It has also been argued that the model's single parameter (α) presents a potentially informative ecological diversity metric, because it summarises the shape of the SAD in a single number. Despite this potential, few empirical tests of the model have been undertaken, perhaps because the necessary methods and software for fitting the model have not existed. Here, we derive a maximum likelihood method to fit the model, and use it to undertake a comprehensive comparative analysis of the fit of the gambin model. The functions and computational code to fit the model are incorporated in a newly developed free-to-download R package (gambin). We test the gambin model using a variety of datasets and compare the fit of the gambin model to fits obtained using the Poisson lognormal, logseries and zero-sum multinomial distributions. We found that gambin almost universally provided a better fit to the data and that the fit was consistent for a variety of sample grain sizes. We demonstrate how α can be used to differentiate intelligibly between community structures of Azorean arthropods sampled in different land use types. We conclude that gambin presents a flexible model capable of fitting a wide variety of observed SAD data, while providing a useful index of SAD form in its single fitted parameter. As such, gambin has wide potential applicability in the study of SADs, and ecology more generally.

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Morphological and anatomical characters used for segregating species within the genus Corallina (Corallinaceae, Rhodophyta) have been compiled and evaluated in 120 specimens collected in the Azores. The morphological, anatomical and statistical evaluation of the thirty four segregating characters for the genus Corallina performed in the present study revealed no species segregation, either showing no differences across the whole lot of specimens or being highly variable within sets of plants. This suggests that all studied material belongs to one species, so far Ellisolandia elongata (formely Corallina elongata), thus reinforcing old proposed synonyms. A morphological and anatomical account is provided for this species, considering the whole set of studied specimens.

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The Late Miocene Malbusca outcrop is located in the southeastern coast of Santa Maria Island (Azores, NE Atlantic), interspersed in volcanic formations. At ~20 meters above present sea level, a prominent discontinuous layer of rhodoliths seizes with an extension of ~250 meters. This paper presents the first taxonomic record of fossil rhodolith forming coralline algae for the Miocene of the Azores. The preserved taxonomic features used were the following: (1) arrangement of basal filaments, (2) epithallial cells (when observable), (3) presence of cell fusions, (4) conceptacle type, (5) number of cells layers which conceptacle chamber floors are situated below the surrounding thallus surface and (6) for the sporangial pores, the orientation of the filaments around the conceptacle pores. Based on these characters, six taxa were identified encompassing three Corallinaceae (Lithophyllum prototypum, Lithophyllum sp., Spongites sp., Hydrolithon sp.) and one Hapalidaceae (Phymatolithon calcareum and cf. Phymatolithon sp.). An unidentified coaxial thallus was also present, the coaxial construction ascribing the specimens to the genus Mesophyllum or Neogoniolithon. Taxonomic accounts for the identified taxa are described, illustrated and an identification key is provided. The report of L prototypum represents the first Miocene record and the preservation of the specimens is very good. Miocene coralline algae seem very consistent among deposits but some species are relevant for particular areas, like in the Azores.

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IV Congress of Marine Sciences. Las Palmas de Gran Canaria, June 11th to 13th 2014.

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Dissertação de Mestrado, Biodiversidade e Biotecnologia Vegetal, 17 de Março de 2015, Universidade dos Açores.

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Tese de Doutoramento, Gestão Interdisciplinar da Paisagem, 11 Fevereiro de 2016, Universidade dos Açores.