Anomalias congénitas das artérias coronárias

Congenital coronary artery anomalies are modifications of their origin, course or structure and its incidence varies between 0,2 and 5,6% of the general population. Although the majority is asymptomatic, they are the second leading cause of sudden cardiac death in young athletes. The aim of this study is to highlight the main anomalies with hemodynamic significance, including the anomalous origin of a coronary artery from the opposite sinus and anomalous origin of the left coronary artery from pulmonary artery. The anomalous aortic origin of a coronary artery from the opposite sinus accounts for 14-16% of all cardiac deaths, that unexpectedly occur in healthy children or young athletes during or immediately after exercise. The mechanism responsible for the compression/occlusion of the coronary artery originating from the opposite sinus is still unclear and there are several proposed mechanisms. The clinical presentation of these patients is variable and physical examination is normal in most individuals. Transthoracic echocardiogram is the diagnostic test most commonly used. Treatment and management are controversial topic. The anomalous origin of the left coronary artery from pulmonary artery is a very rare condition and without surgery, most infants die within the first 12 months of life. The echocardiogram is also the method of choice for diagnostic confirmation. The diagnosis of this congenital anomaly in an infant, usually seriously ill, is an indication for urgent surgery. Because these anomalies produce hemodynamic changes, it is important an early diagnosis and treatment.info:eu-repo/semantics/publishedVersio

Introduction: on celebrating Rawls

[Excerpt] The year 2021 marked the centenary of John Rawls' birth and the fiftieth anniversary of the first edition of his opus magnum, A Theory of Justice. The Centre for Ethics, Politics and Society of the University of Minho decided to mark these events by organising a special tribute to Rawls in the framework of the Braga Meetings on Ethics and Political Philosophy, which it organises every year in June. In this context, it was possible to count on the participation —online, due to the Covid-19 pandemic—of Professors Samuel Scheffler (New York University) and Samuel Freeman (University of Pennsylvania), as well as on some dozens of original papers on our author. It is from this collection that we have selected the contributions in this dossier, which we believe illustrate the quality and the main focuses of the debates that took place over the two days of the event

Design of the ISePorto robocup Middle-Size League Robotic Soccer Team: Control, Localisation and Coordination

Proceedings of the 10th Mediterranean Conference on Control and Automation - MED2002 Lisbon, Portugal, July 9-12, 2002This paper describes the design and implementation status of the ISePorto robotic football team for participation in Robocup Middle Size League (F2000). The objectives guiding the project were the applications and research in hybrid control and coordination systems. The system has also an educational support role. A special attention is made to the custom design to allow the execution of complex manoeuvres and team coordinated behaviours. The robot has different pass, shot, and manoeuvre capabilities providing high level tactical and strategic planing and coordination. The current team status is also covered

Análise experimental de telha de aço autoportante

As telhas de aço autoportantes têm uma larga utilização na cobertura de grandes áreas (construções industriais, rurais, desportivas), devido ao seu baixo peso próprio e à sua capacidade resistente permitindo vencer grandes vãos sem necessitar de elementos verticais intermédios para a suportar, proporcionando assim um espaço amplo sem obstáculos. A procura de soluções mais eficientes e otimizadas para a secção transversal destas telhas conduziram a geometrias complexas, cuja análise estrutural requer métodos sofisticados de cálculo. Torna-se necessária a validação de métodos de cálculo (especificações de normas, métodos numéricos) através de ensaios experimentais. Apesar de ter uma vasta aplicação no mercado, esta carece de estudos científicos que descrevam o seu comportamento estrutural face às ações a que estão sujeitas. Com vista a colmatar a falta de estudos neste domínio, este trabalho propõe-se realizar um conjunto de testes experimentais de uma solução de cobertura autoportante com a colaboração da empresa “Blocotelha – Steel Constructions, SA”. A componente experimental desta dissertação consiste em (i) ensaios de caracterização do material, passando pela (ii) análise do comportamento da secção (barra de eixo reto) quando sujeita a compressão axial até ao (iii) estudo da resposta da estrutura em conjunto, com a forma de um arco. Por fim são apresentados os resultados de todos os ensaios sob a forma de tabelas, gráficos e imagens que relacionam os fenómenos estruturais relevantes da chapa em análise tais como (i) relações tensão/extensão de ensaios à tração, e (iii) curvas força/deslocamento, curvas força/tensão e momento/curvatura

Protection of interconnected wind turbines against lightning effects: overvoltages and electromagnetic transientes study

This paper is concerned with direct or indirect lightning strokes on wind turbines, studying overvoltages and electromagnetic transients. As wind power generation undergoes rapid growth, lightning damages involving wind turbines have come to be regarded with more attention. With the aim of providing further insights into the lightning protection of wind turbines, describing the transient behavior in an accurate way, the restructured version (RV) of the electromagnetic transients program (EMTP) is used in this paper. A new case study is presented with two interconnected wind turbines, considering a direct lightning stroke to the blade or considering that lightning strikes the soil near a tower. Comprehensive computer simulations with EMTP-RV are presented and conclusions are duly drawn

Lightning Data Observed With Lightning Location System in Portugal

This paper presents an investigation into cloud-to-ground lightning activity over the continental territory of Portugal with data collected by the national Lightning Location System. The Lightning Location System in Portugal is first presented. Analyses about geographical, seasonal, and polarity distribution of cloud-to-ground lightning activity and cumulative probability of peak current are carried out. An overall ground flash density map is constructed from the database, which contains the information of more than five years and almost four million records. This map is compared with the thunderstorm days map, produced by the Portuguese Institute of Meteorology, and with the orographic map of Portugal. Finally, conclusions are duly drawn

Protection of wind energy systems against the indirect effects of lightning

This paper is concerned with the protection of wind energy systems against the indirect effects of lightning. As wind energy is gaining increasing importance throughout the world, lightning damages involving wind energy systems have come to be regarded with more attention. Nevertheless, there are still very few studies in Portugal regarding lightning protection of wind energy systems using models of the Electro-Magnetic Transients Program (EMTP). Hence, a new case study is presented in this paper, based on a wind turbine with an interconnecting transformer, considering that lightning strikes the soil near the tower at a distance such that galvanic coupling occurs through the grounding electrode. Computer simulations obtained by using EMTP-RV are presented and conclusions are duly drawn. (C) 2011 Elsevier Ltd. All rights reserved

Aspectos gerais da situação de lavra para granitos ornamentais no município do Rio de Janeiro

Rio de Janeiro is one of the most important producers of ornamental granites in Brazil. Environmental laws and tributary taxes have been a major hazard to mining activities, in a profitable way, making the miner's production decrease considerably. It is now important a development of a new political attitude towards a better improvement of the exploration.Resum

SOLOS GRAMPEADOS - COMPRIMENTOS MÁXIMOS DE GRAMPOS NOS SOLOS A LESSE DA FALHA DE SALVADOR (BA)

O artigo trata de um estudo sobre o comprimento máximo degrampos na utilização da técnica de solo grampeado para estabilizaçãode taludes de solos localizados a lesse da falha de Salvador, regiãoresponsável por mais de 60 % dos eventos catastróficos envolvendo rupturade encostas. São analisadas, pelo método de Bishop Simplificado,30 áreas de encostas, além de ser apresentado um levantamento bibliográficode mais 8 eventos acontecidos naquela cidade. O trabalho visaa otimização de custos para estabilização de encostas nas áreas deocupação desordenada de baixa renda, alertando para adoção de cunhaspotenciais de ruptura de grande profundidade

Aplicação de Algoritmos Genéticos na Localização de Dispositivos de Manobras para Minimização de Perdas em Redes de Energia Eléctrica

A presente dissertação endereça o problema da minimização de perdas mediante a localização óptima de dispositivos telecomandados que possibilitam, através de reconfiguração topológica, uma potencial redução de perdas numa rede de distribuição de energia eléctrica. Foram desenvolvidas duas metodologias para o efeito: (i) baseada numa busca sequencial de manobras; (ii) mediante a aplicação de algoritmos genéticos adaptados ao problema. A metodologia baseada numa busca sequencial permite obter apenas uma solução optimizada para um determinado cenário. Aplicando os Algoritmos Genéticos estes permitem obter um conjunto de soluções de elevada qualidade que correspondem a várias topologias, todas elas diferentes entre si mas com valores de perdas semelhantes. A localização dos Órgãos de Corte de Rede, foi feita tendo em consideração todas as soluções propostas pelo algoritmo genético adaptadas a todos os cenários de carga definidos. Estas metodologias foram aplicadas a uma rede de 33 barramentos e que permitiu evidenciar a robustez e qualidade das soluções propostas sendo que, no caso desta rede, com a colocação de 8 OCR’s (possibilidade de reconfigurar a rede em 8 pontos diferentes), obteve-se um potencial de redução de perdas entre 35% e 38%. Este resultado é muito relevante uma vez que as perdas em redes de distribuição tipicamente representam 8% a 12% do total de energia eléctrica distribuída