279 research outputs found

    Synthesis of indium tin oxide nanoparticles by a nonhydrolytic sol-gel method

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    Indium tin oxide nanoparticles were synthesized in two different sizes by a nonhydrolytic sol-gel method. These powders were then transformed into ITO via an intermediate metastable state at between 300 and 600 ºC. The presence of characteristic O-In-O and O-Sn-O bands at 480 and 670 cm-1 confirmed the formation of ITO. The X-ray diffraction patterns indicated the preferential formation of metastable hexagonal phase ITO (corundum type) as opposed to cubic phase ITO when the reflux time was less than 3 h and the heat treatment temperature was below 600 ºC. Particle morphology and crystal size were examined by scanning electron microscopy

    Study of the kinetics of martensitic transformation in the USISAR 80T microalloyed steel.

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    No presente trabalho, estudou-se a aplica??o de modelos cin?ticosde transforma??o martens?ticadispon?veis na literatura t?cnica a fim de modelar curvas de fra??o da fase austenita transformada em martensita para o a?o USISAR 80T, estrutural, microligado, de boa temperabilidade e considerado de boa soldabilidade. Ensaios dilatom?tricos foram realizados com taxa de aquecimento de 3?C/s at? a temperatura de austenitiza??o de 920?C, tempo de encharque de 180 segundos e taxas de resfriamento de 25?C/s, 50?C/s, 75?C/s e 100?C/s. Um dos modelos estudados apresentou boa correla??o com os dados experimentais para todas as taxas de resfriamento estudadas, sendo poss?vel ent?o a obten??o de constantes caracter?sticas da transforma??o estudada e a proposi??o de um modelo de previsibilidade para o a?o USISAR 80T.In this work, martensitic kinetic models, available in the technical literature, were studied aiming to model and to predict the austenite to martensite transformation for the USISAR 80T steel, which is a structural, microalloyed, with high hardenability and considered a great weldable steel. Dilatometrictests were performed with a heating rate of 3?C/s until 920?C, with a soaking time of 180 seconds and cooling rates of 25?C/s, 50?C/s, 75?C/s and 100?C/s.One of the studied models showed good agreement with the experimental data for all the employed cooling rates, and it was possible to determinetransformation characteristic constants and suggest a previsibility model for the USISAR 80T steel

    3D microsimulation of milkruns and pickers in warehouses using SIMIO

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    To help the Bosch Car Multimedia Portugal in Ferreiros, Braga to reduce its costs (both in time and space) with its warehouse, a micro simulation model is being developed in Simio. Particularly, the tool needs to be able to model pickers riding milkruns to collect containers of products, from a warehouse, to satisfy the needs of the production lines. In this sense, the storage strategy used on the warehouse, the quantity of requests a picker gets per shift, the time between shifts, the number of types of products, the arrival rate of requests, and the number of milkruns and pickers needs to be adjustable. Additionally, to design the corridors of the warehouse in a configurable way, an Add-in in C#, using the API of Simio, is being developed. Thus, this paper intends to document the first part of the simulation model developed, which consists on the pickers receiving requests and riding their milkruns to collect the respective containers from the warehouse. Five different Simio models compose the main simulation model. Conclusions and future work are discussed.This work has been co-supported by SI I&DT project in joint-promotion nº 36265/2013 (HMIEXCEL - 2013-2015 Project) and by FCT – Fundação para a Ciência e Tecnologia in the scope of the project: PEst-OE/EEI/UI0319/2014

    Desempenho de pacientes esquizofrênicos no Stroop Color Word Test e responsividade eletrodérmica após administração aguda de canabidiol (CBD)

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    OBJECTIVE: The last decade has seen increasing evidence of dysfunctions in the endogenous cannabinoid system in schizophrenia and of its relationship with the typical cognitive impairment of the disorder. Studies in animal models, healthy volunteers, and psychotic patients clearly suggest an antipsychotic-like effect of cannabidiol. This study investigated the effects of cannabidiol on selective attention in 28 schizophrenic patients using the Stroop Color Word Test and on these patients' electrodermal responsiveness to auditive stimuli. METHOD: The subjects attended two experimental sessions, the first one without the administration of drugs. In the second session the subjects were divided into three groups that received either a single dose of cannabidiol 300mg or cannabidiol 600mg or placebo. RESULTS: The three groups did not differ significantly with respect to electrodermal measures in the two experimental sessions. When the first and second sessions were compared improved performance was found in all three groups, with patients who received placebo and cannabidiol 300mg performing better than those who received cannabidiol 600mg. CONCLUSION: The single, acute administration of cannabidiol seems to have no beneficial effects on the performance of schizophrenic patients in the Stroop Color Word Test, although the hypothesis that chronic administration may lead to improvement cannot be disregarded.OBJETIVO: Descobertas relativas a possíveis disfunções do sistema canabinóide endógeno na esquizofrenia e sua relação com o prejuízo cognitivo característico da doença têm aumentado durante a última década. Estudos com modelos animais, voluntários saudáveis e pacientes psicóticos sugerem claramente que o canabidiol possui efeitos antipsicóticos. Este estudo investigou os efeitos do canabidiol sobre a atenção seletiva por meio do Stroop Color Word Test e a responsividade eletrodérmica a estímulos auditivos em 28 pacientes com esquizofrenia. MÉTODO: Duas sessões experimentais foram realizadas, a primeira sem a administração de drogas. Na segunda sessão, os sujeitos foram divididos em três grupos que receberam dose única de canabidiol 300mg, canabidiol 600mg ou placebo. RESULTADOS: Os três grupos não diferiram significativamente no que se refere às medidas eletrodérmicas nas duas sessões experimentais. Os três grupos apresentaram melhora da primeira para a segunda avaliação, com os grupos placebo e canabidiol 300mg superiores ao grupo canabidiol 600mg. CONCLUSÃO: A administração aguda de canabidiol em dose única parece não ter efeitos benéficos sobre o desempenho de pacientes com esquizofrenia no Stroop Color Word Test, embora estes dados não sejam suficientes para refutar a hipótese de que a administração continuada de canabidiol possa resultar em melhora no funcionamento cognitivo em esquizofrenia

    Identificação de gramíneas tropicais com via fotossintética “C 4” pela anatomia foliar

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    The leaf anatomy of 75 forage grass species from 30 genera and one interspecific hybrid was studied to classify them, by the presence or absence of the Kranz-type mesophylic cell structure, in respect to their photosynthetic pathway.  72 of the species presented characteristic Kranz-type leaf anatomy, indicating the C-4 dicarboxylic acid photosynthetic pathway, while 3 (Acroceras macrum, Pharus sp. and Bambusa sp.) showed no Kranz-type, indicating the C-3 Calvin cycle. Characteristic Kranz-type structures are described and ilustrated. In general, plants from the same tribe show similar structure.  It is concluded that all tropical forage grasses of economical importance are C-4 plants.Foi estudada a anatomia da folha de 75 espécies de gramíneas tropicais, pertencentes a 30 gêneros, e mais 1 híbrido interespecífico, com o objetivo de identificá-la em relação a sua via fotossintética mediante a síndrome anatômica da coroa de células mesofílicas. Dentre as espécies estudadas, 72 apresentaram características do grupo C 4 enquanto apenas 3 (Acroceras macrum, Pharus sp. e Bambusa sp) se incluíram no grupo C 3. É apresentada uma descrição dos tipos anatômicos encontrados, verificando-se que, de modo geral, as plantas da mesma tribo apresentam o mesmo tipo anatômico de coroa. O estudo demonstra que todas as espécies de gramíneas forrageiras tropicais de importância econômica se incluem no grupo C 4

    Shell sclerochronology and stable isotopes of the bivalve Anomalocardia flexuosa (Linnaeus, 1767) from southern Brazil: : implications for environmental and archaeological studies

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    We conduct the first stable isotopic and sclerochronological calibration of the bivalve Anomalocardia flexuosa (Linnaeus, 1767) in relation to environmental variables in a subtropical coastal area of southern Brazil. We investigate incremental shell growth patterns and δ18O and δ13C values of modern specimens collected alive from the Laguna Lagoonal System (LLS). As shells of Anomalocardia flexuosa are also the main components of pre-Columbian archaeological shell mounds and middens distributed along the Brazilian coastline, late Holocene archaeological specimens from a local shell mound (Cabeçuda) were selected to compare their stable carbon and oxygen isotopes with those of modern specimens. Shell growth increments, δ18O and δ13C values respond to a complex of environmental conditions, involving, for example, the effects of temperature and salinity. The isotopic information extracted from archaeological specimens from Cabeçuda shell midden in the LLS indirectly indicates that environmental conditions during the late Holocene were different from present day. In particular, intra-shell δ18O and δ13C values of archaeological shells reveal a stronger marine influence at 3 ka cal BP, which is in contrast to the seasonal freshwater/seawater balance that currently prevails at the LLS

    Spatial Factors Play a Major Role as Determinants of Endemic Ground Beetle Beta Diversity of Madeira Island Laurisilva

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    The development in recent years of new beta diversity analytical approaches highlighted valuable information on the different processes structuring ecological communities. A crucial development for the understanding of beta diversity patterns was also its differentiation in two components: species turnover and richness differences. In this study, we evaluate beta diversity patterns of ground beetles from 26 sites in Madeira Island distributed throughout Laurisilva – a relict forest restricted to the Macaronesian archipelagos. We assess how the two components of ground beetle beta diversity (βrepl – species turnover and βrich - species richness differences) relate with differences in climate, geography, landscape composition matrix, woody plant species richness and soil characteristics and the relative importance of the effects of these variables at different spatial scales. We sampled 1025 specimens from 31 species, most of which are endemic to Madeira Island. A spatially explicit analysis was used to evaluate the contribution of pure environmental, pure spatial and environmental spatially structured effects on variation in ground beetle species richness and composition. Variation partitioning showed that 31.9% of species turnover (βrepl) and 40.7% of species richness variation (βrich) could be explained by the environmental and spatial variables. However, different environmental variables controlled the two types of beta diversity: βrepl was influenced by climate, disturbance and soil organic matter content whilst βrich was controlled by altitude and slope. Furthermore, spatial variables, represented through Moran’s eigenvector maps, played a significant role in explaining both βrepl and βrich, suggesting that both dispersal ability and Madeira Island complex orography are crucial for the understanding of beta diversity patterns in this group of beetles.Peer reviewe

    Ordenamento do Território e Planeamento Ambiental : investigação e prática

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    A secção Biologia é coordenada pelo Professor Universitário Armindo Rodrigues.O CIGPT fundado pelos Geógrafos Helena Calado e João Porteiro desenvolveu nas duas últimas décadas um esforço considerável na investigação e prática do Ordenamento Territoria
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