Construçao da conhecimento escolar cientifico na perspectiva da complexidade

A escola também é um espaço para o desenvolvimento social, político, cultural, entre outros, visto seu potencial em formar cidadãos mais críticos, que pode atuar e transformar seu meio. Para isso, o conhecimento escolar científico a ser produzido requer uma aproximação da realidade discente e de seu mundo, o que, de certo, vai ao encontro de um ensino pautado na perspectiva mais complexa. Com o intuito de contribuir na promoção desse tipo de formação, esse trabalho investiga os argumentos que os alunos vão construindo ao longo de aulas de Física voltadas à problemática do Aquecimento Global. O objetivo é identificar alguns elementos que caracterizam o nível de complexidade nas ideias produzidas ao longo das aulas. Metodologicamente, a pesquisa acompanha e analisa a construção dos argumentos dos alunos durante vinte aulas, procurando apontar seus desenvolvimentos através da produção escrita. Dos resultados, foi possível identificar aspectos que mostram que a construção do conhecimento escolar é altamente dinâmica e flexível, visto que as ideias são construídas e desconstruídas ao longo da pesquisa, partindo de níveis de complexidade mais baixos e alcançando níveis mais altos ou se estabelecendo em níveis intermediário

Premature atrial contractions: A predictor of atrial fibrillation and a relevant marker of atrial cardiomyopathy

An increased burden of premature atrial contractions (PACs) has long been considered a benign phenomenon. However, strong evidence of their involvement in the occurrence of atrial fibrillation (AF), ischemic stroke, and excess mortality suggests the need for management. The central question to be resolved is whether increased ectopic atrial rhythm is only a predictor of AF or whether it is a marker of atrial cardiomyopathy and therefore of ischemic stroke. After reviewing the pathophysiology of PACs and its impact on patient prognosis, this mini-review proposes to 1) detail the physiological and clinical elements linking PACs and AF, 2) present the evidence in favor of supraventricular ectopic activity as a marker of cardiomyopathy, and 3) outline the current limitations of this concept and the potential future clinical implications

Vectorisation paramétrée des données textuelles

International audienceAutomatic processing of textual data enables users to analyze semi-automatically and on a large scale the data. This analysis is based on two successive processes: (i) representation of texts, (ii) gathering of textual data (clustering). The software described in this paper focuses on the first step of the process by offering expert a parameterized representation of textual data

Harvesting dissipated energy with a mesoscopic ratchet.

The search for new efficient thermoelectric devices converting waste heat into electrical energy is of major importance. The physics of mesoscopic electronic transport offers the possibility to develop a new generation of nanoengines with high efficiency. Here we describe an all-electrical heat engine harvesting and converting dissipated power into an electrical current. Two capacitively coupled mesoscopic conductors realized in a two-dimensional conductor form the hot source and the cold converter of our device. In the former, controlled Joule heating generated by a voltage-biased quantum point contact results in thermal voltage fluctuations. By capacitive coupling the latter creates electric potential fluctuations in a cold chaotic cavity connected to external leads by two quantum point contacts. For unequal quantum point contact transmissions, a net electrical current is observed proportional to the heat produced.The ERC Advanced Grant 228273 is acknowledged.This is the author accepted manuscript. The final version is available from NPG at http://www.nature.com/ncomms/2015/150401/ncomms7738/abs/ncomms7738.html

Analyse des flocs bactériens et de la microfaune des boues activées para analyse d'Image

Brasil. Ministério da Ciência e Tecnologia. Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).Ambassade de France au Portugal.Ministério da Ciência e Tecnologia. Instituto de Cooperação Científica e Tecnológica Internacional (ICCTI)

Survey of protozoa and metazoa populations in wastewater treatment plants by image analysis and discriminant analysis

The biota present in the activated sludge of a wastewater treatment plant are mainly composed of bacteria, Protozoa and Metazoa. The Protozoa and Metazoa species are important micro-organisms taking part in the ecosystem balance in wastewater treatment plants and are quite sensitive to physical, chemical and operational processes. Several authors have established relationships between the predominance of certain species or groups and some variables of the plant. Such analysis demands the identification and quantification of the different species, which requires skilled workers, specializing in zoology or protozoology, and is time-consuming. To overcome those problems, semi-automatic image analysis and discriminant analysis were carried out for the identification procedures. The overall results were very promising in terms of Protozoa and Metazoa group recognition and of survey of plant conditions. Copyright 2004 John Wiley & Sons, Ltd.Financial support for the co-operation between the Portuguese (Braga) and French (Nancy) teams was provided by the French Embassy in Portugal and ICCTI (Portugal). A. L. Amaral was supported by a PhD grant (PRAXIS XXI/BD/20325/99) of ‘Fundação para a Ciência e Tecnologia’ (Portugal). M. da Motta was supported by a grant of the National Council of Scientific and Technological Development of Brazil (CNPq)

Study on the Performance of Wastewater Treatment Plant by Image Analysis: Validation and Case Study

Um método baseado na análise de imagens foi desenvolvido para caracterizar os flocos de lodo ativado em termos do seu tamanho e forma (dimensão fractal) e da abundância de bactérias filamentosas. Após ter sido testado em experimentos em escala piloto, o método foi validado para estações de tratamento reais. Foram analisadas doze estações de tratamento de esgotos situadas na França e em Portugal, de tamanhos e processos diferentes. Em seguida realizou-se um acompanhamento sobre a estação de Braga (Portugal) que estava com problemas de intumescimento do lodos (“bulking” filamentoso).Automated methods based on image analysis have been developed to characterise activated sludge in terms of size and shape (fractal dimension) of flocs and abundance of filamentous bacteria. After tests on pilot-scale reactors, the method has been validated on samples from twelve different full-scale wastewater treatment plants of different sizes and processes in France and Portugal. Finally sludge morphology changes have been monitored during a bulking event on a full-scale plant in Portugal

Study of protozoa population in wastewater treatment plants by image analysis

Protozoa are important micro-organisms taking part to the ecosystem balance in wastewater treatment plants. A procedure for their semi-automated identification and counting based on image analysis is proposed. The main difficulty is the segmentation of the protozoa as most of them are in contact with the sludge. The protozoa are characterized by the size of their silhouette (area and length) and three shape factors (elongation, circularity and eccentricity). The identification is performed after projecting the resulting 5D space into a 3D space of Principal Components. The rate of automated identification is actually higher than 50% for some of the species found commonly in activated sludge

Epidemiologically relevant container types, indices of abundance and risk conditions for aedes aegypti in Salto (Uruguay), a city under threat of dengue disease

Objective: A study was conducted in Salto (Uruguay), a city recently invaded by Aedes aegypti (Diptera, Culicidae), in order to identify mosquito-producing containers, the relationship between different Aedes aegypti population indices and environmental risk conditions for the dengue vector. Due to uruguayan climatic characteristics, the vector population decreases abruptly during the winter and regrows when temperature rises, resulting in a particular population dynamic that differs from that of tropical regions. Methods: 20 clusters randomly selected (100 household each) were visited twice and water filled containers and immature mosquitoes were quantified. Pupae per person (PPI), pupae per hectare (PPH) and Stegomyia indices were calculated. The number of mosquitoes in each container type was analyzed, and their spatial location wasdescribed. Results: The study was able to detect important epidemiological containers (containers not in use and tanks). While PPI, PPH and Stegomyia indices for the different clusters were correlated, the Stegomyia indices increased significantly between the first and second sampling. Clusters with abundant vegetation, or located on lower groundshowed the highest PPI values. Conclusion: Due to its proximity to areas where dengue fever is endemic, Salto becomes valuable for case studies relevant to other areas in the world that could be invaded by this vector