623 research outputs found

    Integrating DGSs and GATPs in an Adaptative and Collaborative Blended-Learning Web-Environment

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    The area of geometry with its very strong and appealing visual contents and its also strong and appealing connection between the visual content and its formal specification, is an area where computational tools can enhance, in a significant way, the learning environments. The dynamic geometry software systems (DGSs) can be used to explore the visual contents of geometry. This already mature tools allows an easy construction of geometric figures build from free objects and elementary constructions. The geometric automated theorem provers (GATPs) allows formal deductive reasoning about geometric constructions, extending the reasoning via concrete instances in a given model to formal deductive reasoning in a geometric theory. An adaptative and collaborative blended-learning environment where the DGS and GATP features could be fully explored would be, in our opinion a very rich and challenging learning environment for teachers and students. In this text we will describe the Web Geometry Laboratory a Web environment incorporating a DGS and a repository of geometric problems, that can be used in a synchronous and asynchronous fashion and with some adaptative and collaborative features. As future work we want to enhance the adaptative and collaborative aspects of the environment and also to incorporate a GATP, constructing a dynamic and individualised learning environment for geometry.Comment: In Proceedings THedu'11, arXiv:1202.453

    Toxicidade aguda de Parathion Metil para Danio rerio (Teleostei, Cyprinidae), em condições tropicais.

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    Neste estudo a toxicidade de Parathion metil foi avaliada para Danio rerio, uma espécie de peixe usada como indicadora em ensaios toxicológicos

    The role of European «ro-ro» port terminals in the automotive supply chain management

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    http://www.sciencedirect.com/science/article/B6VG8-4V5XNYN-2/2/e3b9cc9ae1d3da27edb4977da8fc19e

    Electrophysiological answer to a checkerboard stimulus: A pilot study

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    Electroencephalography is a clinical signal that reveals the brain's electrical activity. In this category, the Visual Evoked Potentials (VEP) is one of the most frequent measures, especially when it is necessary to assess the maturity and function of the central visual system. The Electrodermal Activity (EDA) data gives information about skin conductance, and it is used to evaluate autonomic sympathetic reactions, often related to neuropsychological states. It could be used with all ages and in young subjects with healthy development or clinical practice with children with atypical development. In this paper, we propose an experimental setup based on checkerboard stimuli to assess the evolution of visual system development of preterm infants. This experimental protocol was applied to two female preterm born infants of 4 and 6 months of corrected age. The preliminary findings show that, as expected, the P100 latencies and amplitude are still different from those expected for adults and older children. However, the older infant presents results more similar to adults, corresponding to having a more mature visual system. Concerning EDA, it was observed that the older infant presents more responses to the stimulus, a higher level of skin conductance, and a shorter latency time than the younger infant, which is congruent with what is expected, given the maturation of the nervous system. The methodology used in this pilot application and the algorithm defined seem adequate to use in a longitudinal study to follow the evolution of preterm and term infants

    Towards an electroless deposition of gold on metallic substrates using ionic liquids as electrolytes

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    Recent research has suggested a number of applications for gold in fuel cells and related hydrogen fuel processing, which include light weight corrosion resistance bipolar plates and the incorporation of gold as catalyst to provide improvements in electrode conductivity, among others. This paper reports on the electroless deposition of gold on copper substrates from a HAuCl4.3H2O solution in 1-butyl-1- methylpyrrolidinium dicyanamide (BMP-DCA), in laboratory atmospheric conditions. The electrochemical behaviour of the plating solution was studied by potential sweep techniques. Results suggest that gold ions are reduced and deposited on copper without the aid of external polarization, probably by displacement deposition involving copper dissolution, since no other oxidation reaction was identified. Preliminary studies using SEM/EDX showed that compact gold thin films, deposited on copper substrates at 333 K, present a granular nanostructured morphology

    A comparative benchmarking analysis of main Iberian container terminals: a DEA approach

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    Benchmarking is an important tool to organisations to improve their productivity, product quality, process efficiency or services. From Benchmarking the organisations could compare their performance with competitors and identify their strengths and weaknesses. This study intends to do a benchmarking analysis on the main Iberian Sea ports with a special focus on their container terminals efficiency. To attain this, the DEA (data envelopment analysis) is used since it is considered by several researchers as the most effective method to quantify a set of key performance indicators. In order to reach a more reliable diagnosis tool the DEA is used together with the data mining in comparing the sea ports operational data of container terminals during 2007.Taking into account that sea ports are global logistics networks the performance evaluation is essential to an effective decision making in order to improve their efficiency and, therefore, their competitiveness

    Acceptance of dishes based on mechanically separated meat of tambaqui (Colossoma macropomum) in a public school, Brazil.

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    In Brazil, due to economic and social factors, public policies are needed to grant access to quality nutrition in school. This provision should respect the local food culture; however, in the North, the region with the highest production of inland fisheries, fish consumption among students is still very low. The aim of the present study is to characterize Tambaqui (Colossoma macropomum) MSM, suggest planned school dishes based on this MSM and assesses their acceptability among students at the elementary and high school levels in northern Brazil. The study was carried out over one month and was a quantitative (hedonic scale and leftover/intake index) and qualitative research about preference. The participants were 120 elementary- and high-school students chosen randomly after they were authorized by their parents or legal guardians. Fish-based dishes were inserted in the diet of schoolchildren and their acceptability was evaluated. The children were also inquired about their fish consumption routines. The statistical analyses used were frequency tables and chi-squared independence test associated with Fisher?s exact test. Two dishes were well accepted by the students; however, the results showed that fish acceptance among younger students are higher than among adolescents. So, policies that promote fish intake and a healthy lifestyle must be stimulated since the early grades

    Regional rainfall thresholds for landslide occurrence using a centenary database

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    This work proposes a comprehensive method to assess rainfall thresholds for landslide initiation using a centenary landslide database associated with a single centenary daily rainfall data set. The method is applied to the Lisbon region and includes the rainfall return period analysis that was used to identify the critical rainfall combination (cumulated rainfall duration) related to each landslide event. The spatial representativeness of the reference rain gauge is evaluated and the rainfall thresholds are assessed and calibrated using the receiver operating characteristic (ROC) metrics. Results show that landslide events located up to 10 km from the rain gauge can be used to calculate the rainfall thresholds in the study area; however, these thresholds may be used with acceptable confidence up to 50 km from the rain gauge. The rainfall thresholds obtained using linear and potential regression perform well in ROC metrics. However, the intermediate thresholds based on the probability of landslide events established in the zone between the lower-limit threshold and the upper-limit threshold are much more informative as they indicate the probability of landslide event occurrence given rainfall exceeding the threshold. This information can be easily included in landslide early warning systems, especially when combined with the probability of rainfall above each threshold.info:eu-repo/semantics/publishedVersio
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