20 resultados para chromaticity discrimination

em Repositório Científico do Instituto Politécnico de Lisboa - Portugal


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Storm- and tsunami-deposits are generated by similar depositional mechanisms making their discrimination hard to establish using classic sedimentologic methods. Here we propose an original approach to identify tsunami-induced deposits by combining numerical simulation and rock magnetism. To test our method, we investigate the tsunami deposit of the Boca do Rio estuary generated by the 1755 earthquake in Lisbon which is well described in the literature. We first test the 1755 tsunami scenario using a numerical inundation model to provide physical parameters for the tsunami wave. Then we use concentration (MS. SIRM) and grain size (chi(ARM), ARM, B1/2, ARM/SIRM) sensitive magnetic proxies coupled with SEM microscopy to unravel the magnetic mineralogy of the tsunami-induced deposit and its associated depositional mechanisms. In order to study the connection between the tsunami deposit and the different sedimentologic units present in the estuary, magnetic data were processed by multivariate statistical analyses. Our numerical simulation show a large inundation of the estuary with flow depths varying from 0.5 to 6 m and run up of similar to 7 m. Magnetic data show a dominance of paramagnetic minerals (quartz) mixed with lesser amount of ferromagnetic minerals, namely titanomagnetite and titanohematite both of a detrital origin and reworked from the underlying units. Multivariate statistical analyses indicate a better connection between the tsunami-induced deposit and a mixture of Units C and D. All these results point to a scenario where the energy released by the tsunami wave was strong enough to overtop and erode important amount of sand from the littoral dune and mixed it with reworked materials from underlying layers at least 1 m in depth. The method tested here represents an original and promising tool to identify tsunami-induced deposits in similar embayed beach environments.

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In this paper we present results on the optimization of multilayered a-SiC:H heterostructures that can be used as optical transducers for fluorescent proteins detection using the Fluorescence Resonance Energy Transfer approach. Double structures composed by pin based aSiC:H cells are analyzed. The color discrimination is achieved by ac photocurrent measurement under different externally applied bias. Experimental data on spectral response analysis, current-voltage characteristics and color and transmission rate discrimination are reported. An electrical model, supported by a numerical simulation gives insight into the device operation. Results show that the optimized a-SiC:H heterostructures act as voltage controlled optical filters in the visible spectrum. When the applied voltages are chosen appropriately those optical transducers can detect not only the selective excitation of specimen fluorophores, but also the subsequent weak acceptor fluorescent channel emission.

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Storm- and tsunami-deposits are generated by similar depositional mechanisms making their discrimination hard to establish using classic sedimentologic methods. Here we propose an original approach to identify tsunami-induced deposits by combining numerical simulation and rock magnetism. To test our method, we investigate the tsunami deposit of the Boca do Rio estuary generated by the 1755 earthquake in Lisbon which is well described in the literature. We first test the 1755 tsunami scenario using a numerical inundation model to provide physical parameters for the tsunami wave. Then we use concentration (MS. SIRM) and grain size (chi(ARM), ARM, B1/2, ARM/SIRM) sensitive magnetic proxies coupled with SEM microscopy to unravel the magnetic mineralogy of the tsunami-induced deposit and its associated depositional mechanisms. In order to study the connection between the tsunami deposit and the different sedimentologic units present in the estuary, magnetic data were processed by multivariate statistical analyses. Our numerical simulation show a large inundation of the estuary with flow depths varying from 0.5 to 6 m and run up of similar to 7 m. Magnetic data show a dominance of paramagnetic minerals (quartz) mixed with lesser amount of ferromagnetic minerals, namely titanomagnetite and titanohematite both of a detrital origin and reworked from the underlying units. Multivariate statistical analyses indicate a better connection between the tsunami-induced deposit and a mixture of Units C and D. All these results point to a scenario where the energy released by the tsunami wave was strong enough to overtop and erode important amount of sand from the littoral dune and mixed it with reworked materials from underlying layers at least 1 m in depth. The method tested here represents an original and promising tool to identify tsunami-induced deposits in similar embayed beach environments.

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A large area colour imager optically addressed is presented. The colour imager consists of a thin wide band gap p-i-n a-SiC:H filtering element deposited on the top of a thick large area a-SiC:H(-p)/a-Si:H(-i)/a-SiC:H(-n) image sensor, which reveals itself an intrinsic colour filter. In order to tune the external applied voltage for full colour discrimination the photocurrent generated by a modulated red light is measured under different optical and electrical bias. Results reveal that the integrated device behaves itself as an imager and a filter giving information not only on the position where the optical image is absorbed but also on it wavelength and intensity. The amplitude and sign of the image signals are electrically tuneable. In a wide range of incident fluxes and under reverse bias, the red and blue image signals are opposite in sign and the green signal is suppressed allowing blue and red colour recognition. The green information is obtained under forward bias, where the blue signal goes down to zero and the red and green remain constant. Combining the information obtained at this two applied voltages a RGB colour image picture can be acquired without the need of the usual colour filters or pixel architecture. A numerical simulation supports the colour filter analysis.

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Storm- and tsunami-deposits are generated by similar depositional mechanisms making their discrimination hard to establish using classic sedimentologic methods. Here we propose an original approach to identify tsunami-induced deposits by combining numerical simulation and rock magnetism. To test our method, we investigate the tsunami deposit of the Boca do Rio estuary generated by the 1755 earthquake in Lisbon which is well described in the literature. We first test the 1755 tsunami scenario using a numerical inundation model to provide physical parameters for the tsunami wave. Then we use concentration (MS. SIRM) and grain size (chi(ARM), ARM, B1/2, ARM/SIRM) sensitive magnetic proxies coupled with SEM microscopy to unravel the magnetic mineralogy of the tsunami-induced deposit and its associated depositional mechanisms. In order to study the connection between the tsunami deposit and the different sedimentologic units present in the estuary, magnetic data were processed by multivariate statistical analyses. Our numerical simulation show a large inundation of the estuary with flow depths varying from 0.5 to 6 m and run up of similar to 7 m. Magnetic data show a dominance of paramagnetic minerals (quartz) mixed with lesser amount of ferromagnetic minerals, namely titanomagnetite and titanohematite both of a detrital origin and reworked from the underlying units. Multivariate statistical analyses indicate a better connection between the tsunami-induced deposit and a mixture of Units C and D. All these results point to a scenario where the energy released by the tsunami wave was strong enough to overtop and erode important amount of sand from the littoral dune and mixed it with reworked materials from underlying layers at least 1 m in depth. The method tested here represents an original and promising tool to identify tsunami-induced deposits in similar embayed beach environments.

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The characteristics of tunable wavelength filters based on a-SiC:H multilayered stacked pin cells are studied both theoretically and experimentally. The optical transducers were produced by PECVD and tested for a proper fine tuning of the cyan and yellow fluorescent proteins emission. The active device consists of a p-i'(a-SiC:H)-n/p-i(a-Si:H)-n heterostructures sandwiched between two transparent contacts. Experimental data on spectral response analysis, current-voltage characteristics and color and transmission rate discrimination are reported. Cyan and yellow fluorescent input channels were transmitted together, each one with a specific transmission rate and different intensities. The multiplexed optical signal was analyzed by reading out, under positive and negative applied voltages, the generated photocurrents. Results show that the optimized optical transducer has the capability of combining the transient fluorescent signals onto a single output signal without losing any specificity (color and intensity). It acts as a voltage controlled optical filter: when the applied voltages are chosen appropriately the transducer can select separately the cyan and yellow channel emissions (wavelength and frequency) and also to quantify their relative intensities. A theoretical analysis supported by a numerical simulation is presented.

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Dissertação de Mestrado em Supervisão em Educação, enquadrada na linha de investigação sobre Desenvolvimento Profissional dos Professores, apresentada à Escola Superior de Educação de Lisboa

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Em Portugal, no final da década de 90 do século XX, começaram a ser desenvolvidas estratégias de discriminação positiva visando garantir o cumprimento da escolaridade obrigatória e a luta contra a exclusão escolar e social, designadamente nas periferias das grandes cidades. É neste contexto que surgem as escolas e os Territórios Educativos de Intervenção Prioritária (TEIP) pelo Despacho nº147-B/ME/96, de 1 de Agosto de 1996. Este programa, inicialmente inspirado nas zonas de intervenção prioritárias francesas, visava a intervenção de vários parceiros locais (professores, alunos, pessoal não docente, associações de pais, autarquias locais, associações culturais e associações recreativas) na elaboração do Projeto Educativo. Com o XVII Governo Constitucional o programa foi redefinido passando a incluir novas vertentes: necessidade de existência de um projeto educativo próprio; consultadoria externa; avaliação periódica de resultados em diferentes domínios (taxas de insucesso e abandono escolar, assiduidade, comportamento, participação, inovações organizacionais, parcerias educativas estabelecidas no âmbito do Programa, etc.). Foi também alargado a todo o território nacional, envolvendo atualmente cento e cinco agrupamentos escolares. Com esta apresentação visamos analisar se as novas políticas e diretrizes, no domínio da educação prioritária, contribuíram para a emergência de novas estratégias pedagógicas, organizacionais e de envolvimento comunitário. Os elementos em que basearemos a nossa análise serão os seguintes: (i) relatório nacional do programa TEIP (2010-2011); (ii) relatórios do programa de avaliação externa das escolas; (iii) entrevistas realizadas aos atores locais, designadamente a coordenadores e consultores dos projetos TEIP. As conclusões da nossa comunicação centrar-se-ão no papel dos atores locais no desenvolvimento do Programa TEIP e no impacto deste programa na melhoria dos resultados académicos, na diminuição da indisciplina e violência escolar e na construção de percursos de vida que contrariem as tendências para a exclusão escolar e social.

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Relatório de estágio apresentado à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Jornalismo.

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Dissertação de mestrado em ciências da educação especialidade educação especial

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Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção de grau de Mestre em Ciências da Educação - Especialização em Educação Especial

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Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Ciências da Educação - Especialidade Educação Especial

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Objetivos – Demonstrar o potencial da espetroscopia (1H) por ressonância magnética na doença degenerativa discal lombar e defender a integração desta técnica na rotina clínico‑imagiológica para a precisa classificação da involução vs degenerescência dos discos L4‑L5 e L5‑S1 em doentes com lombalgia não relacionável com causa mecânica. Material e métodos – O estudo incluiu 102 discos intervertebrais lombares de 123 doentes. Foram estudados 61 discos de L4‑L5, 41 discos de L5‑S1 e 34 discos de D12‑L1. Utilizou‑se um sistema de ressonância magnética de 1,5 T e técnica monovoxel. Obtiveram‑se os rácios [Lac/Nacetyl] e [Nacetyl/(Lac+Lípidos)] e aplicou‑se a ressonância de lípidos para avaliar a bioquímica do disco com o fim de conhecer o estado de involução vs degenerescência que o suscetibilizam para a instabilidade e sobrecarga. Avaliou‑se o comportamento dos rácios e do teor lipídico dos discos L4‑L5‑S1 e as diferenças apresentadas em relação a D12‑L1. Foi também realizada a comparação entre os discos L4‑L5, L5‑S1 e D12‑L1 na ponderação T2 (T2W), segundo a classificação ajustada (1‑4) de Pfirrmann. Resultados – Verificou‑se que os rácios e o valor dos lípidos dos discos L4‑L5‑S1 apresentaram diferenças estatisticamente significativas quando relacionados com os discos D12‑L1. O rácio [Lac/Nacetyl] em L4‑L5‑S1 mostrou‑se aumentado em relação a D12‑L1 (p=0,033 para os discos com grau de involução [1+2] e p=0,004 para os discos com grau [3+4]). Estes resultados sugerem que a involução vs degenerescência dos discos nos graus mais elevados condiciona um decréscimo do pico do Lactato. O rácio [Nacetyl/(Lac+Lip)] discrimina os graus de involução [1+2] do [3+4] no nível L4‑L5, apresentando os valores dos rácios (média 0,65 e 0,5 respetivamente com p=0,04). O rácio médio de [Nacetyl/(Lac+Lip)] dos discos L4‑L5 foi 1,8 vezes mais elevado do que em D12‑L1. O espetro lipídico em L4‑L5‑S1 nos graus mais elevados não mostrou ter uma prevalência constante quanto às frequências de ressonância. Conclusão – A espetroscopia (1H) dos discos intervertebrais poderá ter aplicação na discriminação dos graus de involução vs degenerescência e representar um contributo semiológico importante em suplemento à ponderação T2 convencional. As ressonâncias de lípidos dos discos L4‑L5 e L5‑S1, involuídos ou degenerados, devem ser avaliadas em relação a D12‑L1, utilizando este valor como referência, pois este último é o nível considerado estável e com baixa probabilidade de degenerescência.

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Mestrado em Contabilidade e Gestão das Instituições Financeiras

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We present an analysis and characterization of the regional seismicity recorded by a temporary broadband seismic network deployed in the Cape Verde archipelago between November 2007 and September 2008. The detection of earthquakes was based on spectrograms, allowing the discrimination from low-frequency volcanic signals, resulting in 358 events of which 265 were located, the magnitudes usually being smaller than 3. For the location, a new 1-D P-velocity model was derived for the region showing a crust consistent with an oceanic crustal structure. The seismicity is located mostly offshore the westernmost and geologically youngest areas of the archipelago, near the islands of Santo Antao and Sao Vicente in the NW and Brava and Fogo in the SW. The SW cluster has a lower occurrence rate and corresponds to seismicity concentrated mainly along an alignment between Brava and the Cadamosto seamount presenting normal faulting mechanisms. The existence of the NW cluster, located offshore SW of Santo Antao, was so far unknown and concentrates around a recently recognized submarine cone field; this cluster presents focal depths extending from the crust to the upper mantle and suggests volcanic unrest No evident temporal behaviour could be perceived, although the events tend to occur in bursts of activity lasting a few days. In this recording period, no significant activity was detected at Fogo volcano, the most active volcanic edifice in Cape Verde. The seismicity characteristics point mainly to a volcanic origin. The correlation of the recorded seismicity with active volcanic structures agrees with the tendency for a westward migration of volcanic activity in the archipelago as indicated by the geologic record. (C) 2014 Elsevier B.V. All rights reserved.