938 resultados para Morfologia - Ria de Aveiro (Portugal)
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The aim of this paper is to make a characterization of water quality problems, in the river Vouga, regarding its use for public water supply. The river Vouga basin is located in a mountainous area, draining to the coastal lagoon of the Ria de Aveiro. Other medium size rivers also contribute to the load of pollution entering the estuarine system of the Ria de Aveiro. Two major impacts of the pollution in the river Vouga basin were identified. One is the eutrophication process of the lower reach of the river, including the Ria de Aveiro; the other is the occasional deterioration in the quality of the water abstracted from the medium reach of river Vouga. The causes of this deterioration are related to the enrichment of the river water with organic material. To improve the river water quality, both urban wastewater and agriculture related sources, must be controlled.
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Marine Recirculating Aquaculture Systems (RAS) produce great volume of wastewater, which may be reutilized/recirculated or reutilized after undergoing different treatment/remediation methods, or partly discharged into neighbour water-bodies (DWW). Phosphates, in particular, are usually accumulated at high concentrations in DWW, both because its monitoring is not compulsory for fish production since it is not a limiting parameter, and also because there is no specific treatment so far developed to remove them, especially in what concerns saltwater effluents. As such, this work addresses two main scientific questions. One of them regards the understanding of the actual (bio)remediation methods applied to effluents produced in marine RAS, by identifying their advantages, drawbacks and gaps concerning their exploitation in saltwater effluents. The second one is the development of a new, innovative and efficient method for the treatment of saltwater effluents that potentially fulfil the gaps identified in the conventional treatments. Thereby, the aims of this thesis are: (i) to revise the conventional treatments targeting major contaminants in marine RAS effluents, with a particular focus on the bioremediation approaches already conducted for phosphates; (ii) to characterize and evaluate the potential of oyster-shell waste collected in Ria de Aveiro as a bioremediation agent of phosphates spiked into artificial saltwater, over different influencing factors (e.g., oyster-shell pre-treatment through calcination, particle size, adsorbent concentration). Despite the use of oyster-shells for phosphorous (P) removal has already been applied in freshwater, its biosorptive potential for P in saltwater was never evaluated, as far as I am aware. The results herein generated showed that NOS is mainly composed by carbonates, which are almost completely converted into lime (CaO) after calcination (COS). Such pre-treatment allowed obtaining a more reactive material for P removal, since higher removal percentages and adsorption capacity was observed for COS. Smaller particle size fractions for both NOS and COS samples also increased P removal. Kinetic models showed that NOS adsorption followed, simultaneously, Elovich and Intraparticle Difusion kinetic models, suggesting that P removal is both a diffusional and chemically rate-controlled process. The percentage of P removal by COS was not controlled by Intraparticle Diffusion and the Elovich model was the kinetic model that best fitted phosphate removal. This work demonstrated that waste oyster-shells, either NOS or COS, could be used as an effective biosorbent for P removal from seawater. Thereby, this biomaterial can sustain a cost-effective and eco-friendly bioremediation strategy with potential application in marine RAS.
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This paper intends to explore the relative importance of different Intellectual Capital (IC) dimensions regarding their contribution to the perceived performance of an Higher Education Organization (HEO). It also seeks to discuss the role of IC and performance measurement in these organizations. This is done through a case study conducted in a Portuguese HEO. The particularities of this type of organization turns it into a very interesting empirical ground for IC research. Evidence suggests that although human, structural and relational capital should contribute as a “whole” to the performance of an HEO, human resources have an added importance as source of knowledge. Results also suggest an ‘overlap’ between IC and performance indicators. Despite the validity of the interpretations provided in the context of the case study, generalization to other situations should only be conducted in a theoretically framed manner. This paper contributes to the development of IC research in a specific type of organization: an HEO. This empirical context is still underexplored, namely regarding the relationship between IC and performance. This study provides important managerial implications for HEOs and their members, who are concerned with its performance and competitiveness.
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As costas arenosas estão actualmente sujeitas a intensos processos erosivos, resultado tanto de actividades humanas como de processos naturais. Na costa portuguesa, este aspecto é bem evidente pelo recuo da linha de costa, pela diminuição da largura das praias, pela degradação dos sistemas dunares e principalmente, pela proliferação de obras fixas de protecção costeira ao longo da linha de costa. Desde a última metade do século passado que a Vagueira tem sido submetida a um intenso processo erosivo, resultando num acentuado recuo da linha de costa. A principal causa apontada para este facto, é a retenção de sedimentos por parte do molhe Norte do porto de Aveiro, impedindo-os de serem transportados pela deriva litoral. Existem também outras causas que contribuem para o acelerar deste processo, tais como a diminuição da quantidade de sedimentos fornecida pela deriva litoral e a retenção de sedimentos por parte das obras transversais de defesa costeira. Nos dias de hoje, a erosão costeira é um verdadeiro risco, e mesmo com a existência de obras fixas de protecção costeira, o avanço do mar é uma constante. Na Vagueira, a pressão urbana sobre o ecossistema costeiro, alterando as suas morfologias e interferindo no seu dinamismo, tem sido um factor interveniente no processo da erosão neste sector costeiro. Desde 1958, tem-se observado um recuo efectivo da linha de costa na Praia da Vagueira, e hoje em dia já se verifica a quase completa destruição do cordão dunar frontal e a construção de diques arenosos na tentativa de impedir a abertura de um novo canal de ligação entre o canal de Mira e o oceano e de proteger valores naturais irrecuperáveis. A construção da cartografia para cada ano em estudo permitiu a quantificação dos valores médios e absolutos do recuo da linha de costa na Vagueira desde 1958 a 2002. A monitorização da praia da Vagueira entre Outubro de 2002 e Outubro de 2003 permitiu a caracterização da praia emersa e apontar o comportamento geral da área em estudo.
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Brackish water ecosystems are often exposed to wide variations in environmental variables, including temperature and salinity, which may cause strong selective pressures on organisms modifying the genetic patterns of species. The aim of this work was to test whether there is a ‘divergence-with-gene flow’ in coastal lagoon populations of white seabream (Diplodus sargus) (Ria Formosa, S Portugal and Mar Menor, SE Spain) respect to four marine populations, by using partial sequences of cyt b mitochondrial gene and information from nine microsatellite loci. Genetic diversity was highest in both coastal lagoons (Mar Menor and Ria Formosa) considering mitochondrial and nuclear markers. Although some of FST population pairwise comparisons were not significant, analyses of molecular variance (AMOVAs) detected differences between groups (coastal lagoon and marine) close to significance. Also, only two haplotypes (Cytb-17 and Cytb-18) were detected in both coastal lagoon sampling sites and these localities (Mar Menor and Ria Formosa) showed the highest number of singletons, some of them with a high number of mutations, as has been already described for other Mar Menor populations (Pomatochistus marmoratus and Holothuria polii). Also, several tests detected significant positive and balancing selection considering mtDNA and microsatellite data. These data support the hypothesis of selection as one of the drivers of the genetic differences found between coastal lagoon and marine populations. The life strategy adopted by Diplodus sargus in coastal lagoons allows it to decrease its mortality rate and improve the heritability of its genes. Also, the increase time spent in coastal lagoons with different temperatures and salinities favours the fitness selection and the maintenance of exclusive haplotypes and genotypes in coastal lagoon inhabitants favouring the ‘divergence-with-gene-flow’.
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Feeding habits of Syngnathus typhle were determined based on monthly sampling during experimental fishing in a coastal lagoon (Ria Formosa, South Portugal) from April 2004 to May 2002. The gut contents of 856 individuals were analysed and quantified with numerical and gravimetric methods, as well as with some complementary indices and measures (vacuity, fullness and relative importance). In this study, this species fed mainly on Copepoda, Mysidacea, small caridean grass shrimps (Hippolytidae and Palaemonidae) and small fishes (Gobiidae) and to a lesser degree on other small invertebrates. No significant differences were found between the diets of males and females. However, significant differences in the fullness indexes of both sexes were observed during the reproductive period. Significant differences in the diet among seasons were also verified but no seasonal trends were discovered. Snout length showed a linear increase with growth while mouth area and total length displayed an allometric relation. Mouth shape varied between an ellipse and an almost perfect circle. The increase in mouth area and snout length as S. typhle grows contributed to the observed ontogenic diet shift with specimens smaller than 10 cm feeding almost exclusively on Copepoda, medium sized specimens feeding mainly on Hippolytidae and Mysidacea, while larger specimens preyed on Hippolytidae, Palaemonidae and Gobiidae. Prey size generally increased with size of S. typhle. (c) 2007 Elsevier Ltd. All rights reserved.
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The faunal communities of four intertidal habitats namely sand, mud, seagrass (Zostera noltii) and seagrass patches (mixSM) of a temperate coastal lagoon, Ria Formosa (southern Portugal), were sampled. A total of 47 species were taken in 428 bottomless drop sampler samples, with the highest number of species and the more commonly occurring species belonging to the Mollusca phylum. The dominance of these gastropod species underlines the importance of the grazing food chain in these habitats. Bittium reticulatum was the most abundant species, being especially abundant in the seagrass habitat. The most frequent and highest biomass species in the community was Carcinus maenas, a predator that makes use of the available resources and that is adapted to the highly variable intertidal environment. Pomatoschistus microps was the most abundant fish species, with highest densities in the mud habitat, which demonstrates an ability to occupy a low depth area. The seagrass; habitat had the highest diversity, abundance and biomass, followed by the mixSM habitat and was different from all the others. Assemblages were highly influenced by the presence of vegetation, providing forage and refuge from predation. A well defined summer group was identified in all habitats. These results highlight the importance of seagrass beds and the idea that their decrease implies the decrease of lagoon production through the impoverishment of the trophic structure of the lagoon. (C) 2008 Elsevier Ltd. All rights reserved.
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Dissertação mest., Gestão da Água e da Costa, Universidade do Algarve, 2007
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Dissertação de Mestrado, Estudos Marinhos e Costeiros, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2009
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Tese dout., Ciências e Tecnologias do Ambiente, Universidade do Algarve, 2007
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Trabalho que investiga a recepção dos Kinder - und Hausmärchen em Portugal, fruto duma aturada e minuciosa pesquisa documental. Com efeito, Teresa Cortez passa em revista os livros e publicações periódicas enquadrados entre 1837 — data do aparecimento das primeiras traduções de contos dos KHM, no periódico lisboeta Biblioteca Familiar e Recreativa — e 1910, data a que a autora estendeu a sua pesquisa. Cada incidência da presença dos contos dos Grimm em Portugal é cuidadosamente investigada, contextualisada e analisada, Assim, à medida que vemos surgir, primeiro esparsas em revistas destinadas a um público infantil, e sem indicação de autoria, traduções (do francês) dos KHM, vamo-nos inteirando sobre o epírito e motivações do seu aparecimento, quer partindo do estudo comparativo com o texto de origem, quer de um exame da publicação de chegada, alargando-se a pesquisa aos seus editores e autores. Todo o processo de recepção dos contos de Grimm vai sendo examinado pela autora à luz dos movimentos das últimas décadas do séc. XIX e primeira do séc. XX, nomeadamente o nacionalismo neo-romântico e o positivismo.
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Tese de dout., Ciências do Mar, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2010
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Dissertação de mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015
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En Portugal, sobre todo en la región de Aveiro, las estructuras de fábrica de adobe fueron el sistema constructivo predominante durante la primera mitad del siglo XX. En la actualidad es aún significativo el legado del patrimonio – cerca de 30% de las construcciones existentes – el cual está formado por un conjunto significativo de construcciones de elevado valor histórico y arquitectónico. En las últimas décadas se ha descuidado su rehabilitación, que ha redundado en el estado actual de daño en muchas de estas construcciones, con desfavorables condiciones de seguridad, y en algunos casos comprometiendo su uso. No obstante, en los últimos años, se observa un creciente interés, asociado a factores ambientales, económicos y de salvaguarda del patrimonio, tanto por parte de las administraciones locales como en el ámbito de los inversores privados, por la conservación y rehabilitación de estas construcciones. Ante esta nueva realidad, que pone de manifiesto la necesidad de desarrollar soluciones y técnicas de intervención que permitan, a través de la rehabilitación y/o refuerzo, prolongar la vida útil de estas estructuras, en la Universidad de Aveiro un grupo de investigadores viene desarrollando un trabajo multidisciplinar sobre las construcciones de adobe en Portugal. El objetivo principal del mismo se centra en la creación de una base de resultados experimentales que apoye las intervenciones de rehabilitación y/o refuerzo del patrimonio edificado, y el desarrollo de soluciones de mejora de su comportamiento estructural. Esta investigación se constituye como un guía que procura contribuir al conocimiento de estas fábricas, enfocado sobre todo a la rehabilitación de las mismas, aportando información que permita a los diferentes profesionales que trabajan en este ámbito actuar en la conservación de este patrimonio
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Vols. 1-8 by M. Pinheiro Chagas, continued by J. Barbosa Colen and Marques Gomes.