Receiver design for nonlinearly distorted OFDM : signals applications in radio-over-fiber systems

Tese de doutoramento. Engenharia Electrotécnica e de Computadores. Universidade do Porto. Faculdade de Engenharia. 201

Portuguese Diplomatic Correspondence and Information Channels during the War of the Spanish Succession

During the War of the Spanish Succession, Portugal joined the Grand Alliance in 1703. It made it involved, from that year on, in the conflict that included most of the major European Powers in a dispute for the Spanish throne, which, ultimately, represented a contest for dominance in Europe. Under these circumstances, several diplomats were in charge of representing Portugal at the main European courts, protecting its interests and communicating regularly with the court of Lisbon.This paper addresses an understudied set of the correspondence written in this period by Francisco de Sousa Pacheco, the Portuguese envoy to The Hague, to João de Almeida Portugal, Portuguese ambassador to the court of Archduke Charles of Habsburg, one of the pretenders to the Spanish throne, in Barcelona. The main objective of this article is to study the information network established in Europe, mainly in the Grand Alliance side, and the different routes letters followed from The Hague to Barcelona, either using the existing postal system or known intermediaries. Letters were not the only means diplomats had to convey information to their addressees. They also sent other sources of information, like periodicals, accounts of events and pieces of information gathered from different sources, including propaganda in its various forms. It also analyses the developments of the war, the structure and evolution of these letters and the struggle of these diplomats with the other states to make sure their commitments to send military and financial support to the troops were fulfilled. He also wrote about the espionage within the various courts, and the interception diplomatic letters suffered from the opposite side.Ultimately, we’ll see the efforts of these ambassadors as a means for Portugal to gain recognition within Europe, although it ended up with an increasing dependency on foreign states support

Modulation of fear by transcranial direct current stimulation (tDCS)

Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2019Contexto: Embora a psicoterapia de exposição seja promissora no tratamento de doenças do foro nervoso e transtornos de medo como a perturbação de stress pós-traumático (PTSD), a maioria dos doentes não adquire total remissão da doença. Vários estudos sugerem a estimulação por corrente direta transcraniana (tDCS) como uma terapia capaz de facilitar o processo de extinção do medo, tendo este procedimento interesse como adjuvante para o aumento de eficácia da psicoterapia. Objetivo: O objetivo deste estudo foi explorar o efeito de tDCS repetitivo na aquisição e consolidação da extinção do medo, usando o paradigma do condicionamento e extinção do medo em ratinhos. Numa segunda experiência, teve-se como objetivo o estudo do mecanismo de ação do tDCS no córtex pré-frontal (PFC), através do uso de um procedimento de microdiálise em ratinhos, de modo a analisar o efeito do tDCS na libertação de neurotransmissores no PFC. Métodos: Uma semana pós-cirurgia, ratinhos C57BL/6J machos (N=31) foram sujeitos a um procedimento de condicionamento do medo por via auditiva, seguido de tDCS anodal a 0.2 mA, 2 x 20 min/dia, durante cinco dias. Posteriormente, um protocolo de extinção foi executado, avaliando a memória de extinção 1 e 21 dias após a extinção. Num outro procedimento, ratinhos (N=6) foram submetidos a microdiálise através de perfusão com fluído cerebrospinal artificial por uma sonda microdialítica, colocada no PFC, sendo recolhidas amostras antes, durante, e após estimulação. Resultados: Os resultados demonstraram diferença significativa entre os grupos experimentais na aquisição da memória de extinção. Aquisição acelerada da extinção foi observada em ratinhos sujeitos a tDCS, no entanto, não foram observados resultados significativos na retenção da extinção. Foram também observados uma redução do medo contextual nos ratinhos sujeitos a tDCS, assim como uma correlação entre o efeito de extinção e o patamar de base de medo em ratinhos. Os resultados da microdiálise não foram conclusivos. Conclusão: Estes resultados demonstram potencial para o uso de tDCS como adjuvante na extinção do medo. No entanto, serão necessários mais estudos para clarificar o seu mecanismo de ação, os seus efeitos na retenção da extinção em modelos patológicos, e o seu efeito a longo prazo.Background: Although there is promise for exposure-based psychotherapy in the treatment of anxiety and trauma-related disorders such as post-traumatic stress disorder (PTSD), most patients fail to achieve full remission. Several studies suggest that transcranial direct current stimulation (tDCS), a safe and non-invasive technique, can be used to facilitate the fear extinction process. Therefore, this procedure seems to be of interest to potentiate the efficacy of exposure-based therapy. Aim: The aim of this master thesis was to explore the effect of repeated tDCS on the acquisition and consolidation of fear extinction, using the fear conditioning and extinction paradigm in mice. In a second experiment, we aimed to help unravel the mechanism of action of tDCS in the prefrontal cortex (PFC) by exploring the effects of tDCS on the release of dopamine, serotonin and noradrenaline in this brain region, using a microdialysis procedure in mice. Methods: Following one week of recovery from surgery, male C57BL/6J (N=31) were subjected to auditory fear conditioning, followed by 2 x 20 min/day anodal tDCS at 0.2 mA for five consecutive days. Extinction training was then performed, and retention of fear extinction was evaluated 1 day and 21 days afterwards. Microdialysis experiment was performed in mice (N=6) by perfusing a microdialysis probe, placed during surgery in the PFC, with artificial cerebrospinal fluid. Samples were collected before, during, and after tDCS stimulation. Results: The results demonstrated a significant difference between the experimental groups in the acquisition of extinction. Accelerated acquisition of extinction was observed in mice subjected to tDCS, whereas, no significant effects on the retention of extinction were observed. Also, a reduction in contextual fear levels in tDCS mice could be observed, as well as a significant correlation between extinction effect and baseline level of fear in mice. Microdialysis results were not conclusive. Conclusion: These results show potential for the use of tDCS as an adjuvant to extinction training. However, further studies are necessary to clarify its mechanism of action and the effects on extinction retention in a model of PTSD, and long-term effect on retention of extinction memory.Vrije Universiteit Brusse

Important problem features for the promotion of onceptual understanding in introductory electronics

This article describes an investigation in which a set of problems, specifically designed to develop conceptual understanding in introductory Electronics, were used as a teaching and learning strategy in an active learning setting. Some of the suggested problems have similarities with those presented by concept inventories, in that they are designed to address common students’ misconceptions. The goal, however, is not to detect misconceptions, but rather to challenge students’ conceptual reasoning. The investigation setting, integrated in the project-based learning environment established at the Higher Education Polytechnic School of Águeda (University of Aveiro, Portugal) since 2001, was designed as a source of abundant data, that included field notes, students written responses to the open problems and interviews. Qualitative analysis was used to identify important problem features that seem to prompt conceptual reasoning, and to evaluate the approach. Although the setting and the learning environment are described in some detail, to set the scene and provide context for the issues being discussed, this article concentrates on the problems and their important features in the promotion of conceptual understanding. Examples of the various formats of problems used in the investigation are provided to better illustrate the discussion. Results of the analysis indicate that the use of such problems does seem to have a positive impact in the conceptual reasoning of the students. However, students also report a generalized feeling of insecurity, for every new problem presented an emotional challenge, as well as a challenge to their assumptions. The analysis also indicates that it is important to seek a proper balance between the qualitative and quantitative components of the problems suggested to the students. As a conclusion, the article will offer a summary of the most important problem features in the promotion of conceptual understanding, as far as the results of this investigation are concerned

Unsupervised Classification of Uterine Contractions Recorded Using Electrohysterography

Pregnancy still poses health risks that are not attended to by current clinical practice motorization procedures. Electrohysterography (EHG) record signals are analyzed in the course of this thesis as a contribution and effort to evaluate their suitability for pregnancy monitoring. The presented work is a contributes with an unsupervised classification solution for uterine contractile segments to FCT’s Uterine Explorer (UEX) project, which explores analysis procedures for EHG records. In a first part, applied processing procedures are presented and a brief exploration of the best practices for these. The procedures include those to elevate the representation of uterine events relevant characteristics, ease further computation requirements, extraction of contractile segments and spectral estimation. More detail is put into the study of which characteristics should be chosen to represent uterine events in the classification process and feature selection methods. To such end, it is presented the application of a principal component analysis (PCA) to three sets: interpolated contractile events, contractions power spectral densities, and to a number of computed features that attempt evidencing time, spectral and non-linear characteristics usually used in EHG related studies. Subsequently, a wrapper model approach is presented as a mean to optimize the feature set through cyclically attempting the removal and re-addition of features based on clustering results. This approach takes advantage of the fact that one class is known beforehand to use its classification accuracy as the criteria that defines whether the modification made to the feature set was ominous. Furthermore, this work also includes the implementation of a visualization tool that allows inspecting the effect of each processing procedure, the uterine events detected by different methods and clusters they were associated to by the final iteration of the wrapper model

Microsoft robotics soccer challenge : movement optimization of a quadruped robot

Estágio realizado na Universidade de Aveiro e orientado pelo Prof. Doutor Nuno LauTese de mestrado integrado. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200

A população lésbica em estudos da saúde: contributos para uma reflexão crítica

Durante décadas, no pensamento e nas práticas das ciências da saúde e da psicologia a sexualidade lésbica foi associada à patologia. Ao longo do século XX, este posicionamento modificou-se. Este trabalho analisa essas mudanças numa reflexão teórica focada no domínio da saúde das lésbicas, no qual predominam as concepções e práticas heteronormativas e heterossexistas, tanto na investigação como na prestação de cuidados. Através de uma contextualização crítica da literatura, identificamos as necessidades específicas das lésbicas, questionamos as intervenções dos profissionais e serviços de saúde e propomos medidas de ação concretas de promoção da saúde e de erradicação da desigualdade e discriminação.Abstract: For decades, lesbian sexuality was associated with pathology in the attitudes to and practices of health sciences and psychology. During the twentieth century that position changed gradually. This article analyzes these changes in a theoretical reflection on the domain of lesbian health, dominated by heteronormative and heterosexist concepts and practices both in research and in health care. By means of a critical contextualization of the literature, specific health needs of lesbians were identified and the interventions of health care professionals and services were questioned. Specific concrete actions are proposed in the fields of health promotion and in the eradication of discrimination and inequality in health care

Electrical circuit analysis and technical english: articulation in a project-based learning environment

This paper describes the integration of Electrical Circuit Analysis and Technical English in the same curricular module, in the context of a Project Based Learning (PBL) environment. The idea consists in taking advantage of the PBL setting to provide a context for the learning of the two different subjects in an articulated manner. The results of the evaluation of the first iteration of this experiment will also be discussed

A Problemática da Divulgação da Cultura Científica Usando os Recursos Proporcionados pela Internet e pelas Redes Telemáticas

Desde há alguns anos a esta parte, conceitos como Cultura Científica e Sociedade de Informação têm aparecido associados de uma forma quase siamesa. O exercício a que nos propomos é separar estes conceitos numa cirurgia de interdependências, particularidades e complementaridades. O Índice de Cultura Científica de um povo é um parâmetro que, de uma forma quase dogmática, expõe as potêncialidades e fragilidades do mesmo em relação a todo o processo de evolução individual, social e tecnológica. No entanto há uma pergunta que não se pode deixar de fazer quando em cogitação àcerca deste tema. E essa pergunta prende-se com a definição do conceito em si: Afinal o que é a Cultura Científica de um povo? Como se afere de uma forma clara esse índice? Pode-se falar das percentagens de escolarização (luta ainda longe de ser vencida), do boom de cursos de formação técnica no início dos anos 90 e subsequente desinvestimento na mesma na segunda metade desta década (fenómeno pelo menos digno de alguma reflexão), da entrada e saída relâmpago de empresas de cariz técnico e alta especificidade tecnológica (e correspondente investimento com as consequências sociais e económicas inerentes) do espaço nacional... Enfim, instabilidade própria de uma juventude económico-social gerida on the fly “sem tempo” para projectos a longo prazo. Que conclusões devemos tirar? Que a cultura científica do povo português teve um pico no meio da década de 90 e começa a decaír agora ou que todo este processo é mais complexo que isso enão pode ser avaliado com base em dados meramente objectivos