Caracterização não-linear de agregados de antenas para aplicações 5G

The present mobile scenario demands are stretching the existing telecom infrastructure to the limit. New technologies centred around antenna arrays and spatial multiplexing have been proposed to overcome the challenges imposed by these demands. This work overviews the mobile scenario, scrutinizing demands, presented solutions, challenges and the industry’s perspective of the Fifth Generation of mobile communications. From a careful analysis, the 5G’s most critical radio frequency hardware issues are detailed, and a long-term approach to address them is presented. On the short-term the work focuses on antenna characterization, because antennas are a central part of future wireless communications. Initially, basic antenna concepts are presented, then emphasis is given to microstrip antennas, going through all the steps of designing, optimizing and measuring a rectangular microstrip antenna and an eight element linear antenna array for 5.67GHz. Array features such as scanning and source synthesis are also explored. Finally, the impact of signal nonlinear distortion on the antenna array pattern is studied, aiming to expand state-of-the-art knowledge on how signal nonlinear distortion can limit spatial multiplexing. A theoretical model of the phenomenon is proposed and validated both by electromagnetic simulation and measurements.As crescentes exigências das redes móveis estão a levar a infraestrutura de telecomunicações ao seu limite. Novas tecnologias centradas em agregados de antenas e multiplexagem espacial têm sido propostas para ultrapassar os desafios impostos por tais exigências. Este trabalho apresenta uma visão abrangente das redes móveis atuais, escrutinando as suas exigências, as soluções apresentadas, os desafios adjacentes, bem como a opinião da indústria. Os problemas mais crı́ticos do hardware de radio frequência para a quinta geração de redes móveis são apurados a partir de uma análise detalhada do cenário das redes sem fios, sendo apresentado um plano a longo prazo para abordar estas problemáticas. A curto prazo o trabalho foca-se em caracterização de antenas, visto que as antenas são um ponto central nas comunicações sem fios do futuro. Inicialmente são apresentados conceitos básicos sobre antenas, dando-se de seguida ênfase às antenas microstrip, sendo apresentado todo o processo de sı́ntese, otimização e caracterização de uma antena microstrip retangular e de um agregado de antenas linear de oito elementos com frequência de operação 5.67GHz. Neste âmbito, algumas propriedades dos agregados, como o varrimento angular do feixe eletromagnético e técnicas de sı́ntese de fonte eletromagnética, são também exploradas. Finalmente, apresenta-se um estudo sobre o impacto que a distorção não linear de sinal pode ter no diagrama de radiação do agregado de antenas. O objetivo é expandir os conhecimentos do estado-da-arte acerca das limitações que a distorção não linear pode impor na multiplexagem espacial. Neste sentido, um modelo teórico descritivo deste fenómeno é proposto e validado por simulação eletromagnética e por medições experimentais.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

O caso da fachada num contexto de sustatabilidade

Dissertação de Mestrado Integrado em Arquitetura, com a especialização em Arquitetura apresentada na Faculdade de Arquitetura da Universidade de Lisboa para obtenção do grau de Mestre.O crescimento populacional mundial e as consequências negativas do progresso tecnológico trazem novos desafios à arquitetura que necessita de encontrar novas soluções para reduzir o impacto dos elementos construídos sobre a Natureza. A sustentabilidade na arquitetura ganha um papel importante e a fachada pode contribuir de forma significativa. Por outro lado, a conceção de edifícios na cidade contemporânea não decorre apenas de lógicas “modernistas” de estrita relação forma / função, estando igualmente relacionada com aspetos simbólicos que refletem uma sociedade que é afetada pela mobilidade e constante mudança que o desenvolvimento tecnológico permite. As fachadas como elemento de transição entre o exterior e interior de edifícios que procuram responder a um tempo que o sirva, podem assumir este papel, incorporando movimento, tornando-se dinâmica. A fachada ao incorporar elementos vegetais, enquadra-se nestas duas diferentes perspetivas e desafios, visando preocupações ecológicas e sustentáveis, contribuindo para produzir novas formas de arquitetura, numa combinação incomum entre artificial e vegetal. Para compreender de que modo fachada pode contribuir para a sustentabilidade na arquitetura, procurou-se perceber os seus “padrões”, propondo-se uma sintetização de elementos básicos, que são usados e repetidos em várias situações. O objetivo, com esta criação de ferramentas para o seu entendimento, é perceber como o incremento de elementos vegetais pode contribuir para a criação de soluções que beneficiem o meio ambiente e os indivíduos. Tendo em conta a densidade construtiva e o estado de degradação do edificado nas grandes cidades, e sua consequente poluição, o recurso a elementos vegetais na fachada poderá ser uma solução viável para a reabilitação e reconversão urbana, contribuindo para um futuro sustentável. Através da intervenção nos antigos terrenos do Bairro da Quinta da Vitória, na fronteira com o bairro social existente Alfredo Bensaúde, espera-se ainda demonstrar o caráter social, inclusivo e económico das fachadas com elementos vegetais ao estabelecerem uma ligação entre o espaço público e as habitações, que permite a dinamização das relações humanas e promove, entre outras atividades, a produção agrícola urbana.ABSTRACT: The world population growth and the negative consequences of the technological advances bring new challenges to the architecture that now needs to find new solutions to minimize the environmental impact of buildings. Nowadays, sustainability plays an important role in architecture and the facade can contribute significantly to this matter. On the other hand, the conception of the buildings in the contemporary city does not derive only from logical “modernist” strictly linked to the relation between form and function. It is equally related to symbolic aspects that reflects a society affected by mobility and the constant change allowed by the technological development. The facades as a transitional element between the exterior and interior of buildings that seek to respond this age, can assume this role, incorporating movement, becoming dynamic. By incorporating vegetables elements, the facade fits in these two different perspectives and challenges, aiming ecological and sustainable concerns and contributing to produce new forms of architecture in an unusual combination between artificial and vegetable. To realize in which way the facade can contribute to the sustainability on architecture, is made a search to understand his “patterns” and it is proposed a synthesising of basic elements, which are used and repeated in various situations. By creating these tools to its comprehension, the goal is to understand how the development of the vegetable elements can contribute to the creation of solutions that benefit the environment and the individuals. Taking into account the building`s density and the degradaded state of the construction in large cities and its consequent pollution, the use of vegetables elements on the facade may be a viable solution for the rehabilitation and urban renewal, contributing to a sustainable future. Through the intervention on the former grounds of the Bairro da Quinta da Vitória, next to the social housing neighbourhood Alfredo Bensaúde, is also expected to demonstrate the social, inclusive and economic character of the facades with vegetable elements, creating a link between the public space and households, stimulating the human relations and promoting, among other activities, urban agricultural production.N/

Geo-localization system for people with cognitive disabilities

Technology is present in almost every simple aspect of the people’s daily life. As an instance, let us refer to the smartphone. This device is usually equipped with a GPS module which may be used as an orientation system, if it carries the right functionalities. The problem is that these applications may be complex to operate and may not be within the bounds of everybody. Therefore, the main goal here is to develop an orientation system that may help people with cognitive disabilities in their day-to-day journeys, when the caregivers are absent. On the other hand, to keep paid helpers aware of the current location of the disable people, it will be also considered a localization system. Knowing their current locations, caregivers may engage in others activities without neglecting their prime work, and, at the same time, turning people with cognitive disabilities more independent.Fundação para a Ciência e a Tecnologia (FCT) - project FCOMP-01-0124-FEDER-028980 (PTDC/EEI-SII/1386/2012)ERDF - European Regional Development Funds through the COMPETE Programme (operational programme for competitiveness) project FCOMP-01-0124-FEDER-028980 (PTDC/EEI-SII/1386/2012)

First characterization of preantral follicles in the ovaries of adult alpaca

It is a fact that while even basic reproductive information on alpacas is unavailable, the normal ovarian reserve of this species in comparison to other species is also unidentified. In this study, the ovarian preantral follicles in healthy adult alpacas were characterized in order to establish a general model to in vitro studies. Ten ovaries were collected from five adult alpacas. The ovarian cortex samples were fixed with paraformaldehyde and histological analysis was done. Normal and degenerated follicles percentages were determined. The normal follicles were measured and classified in primordial, transitional, primary and secondary stages.  Most of the preantral follicles present in the ovarian cortex of alpacas were primordial and transitional stages; primary (6.10%) and secondary (0.37%) follicles were rarely found. The primary and secondary follicles were larger in diameter when compared with the primordial and transitional follicles. The largest oocyte diameter was recorded in the secondary follicles (P < 0.05). This study serves to establish a biological model for future reproduction studies in Alpacas or as possible biological model for studies of folliculogenesis in humans

Buscando entender ideologias e conceitos construídos no ensinar/aprender por professores de língua inglesa em uma escola de línguas: para além dos muros da universidade

O presente estudo buscou compreender a construção de ideologias e conceitos presentes em professores de língua inglesa durante o processo de ensino/aprendizagem em uma escola particular do idioma. O estudo tem como fundamentação teórica o processo crítico reflexivo de ensino/aprendizagem presente em diversos trabalhos científicos, como, por exemplo: Pennycook (1994), Cox & Assis-Peterson (2007),  Moita Lopez (2005), Ortiz (2006) e demais pensadores. O objetivo principal deste artigo fundamenta-se no questionamento dos fatores sociais, políticos e culturais que permeiam o ensino/aprendizagem de língua inglesa em escolas de idiomas, por meio da exposição de conceitos e ideologias, feita por professores a aprendizes do idioma durante as aulas

O componente demográfico no desenho das políticas de desenvolvimento urbano

Unavailable.Indisponível

Light microscopical and ultrastructural characterization of goat preantral follicles

Goat ovarian preantral follicles were morphologically and ultrastructurally described in this work. Primordial follicles are oocytes surrounded by one layer of squamous or squamouscuboidal granulosa cells; primary follicles have a single layer of cuboidal granulosa cells, and secondary follicles are oocytes surrounded by two or more layers of cuboidal granulosa cells. At all developmental stages a thick layer of glycoproteins, the basement membrane, surrounded the preantral follicles. The quiescent oocyte is spherical or oval and it has a large eccentrically located nucleus with a conspicuous nucleolus. The organelles were uniformly distributed in the cytoplasm. A large number of vesicles were spread throughout the cytoplasm in all the oocytes. The cytoplasm of oocytes also contains numerous rounded mitochondria besides the usual organelles. As the follicle develops, the mitochondria become elongated. The communication between the oocyte and the granulosa cells is apparently mediated through endocytosis as indicated by the abundant coated pits and vesicles noted in the cortical cytoplasm of the oocyte. The oocyte plasma membrane presented projections that penetrated between adjacent granulosa cells and a few short microvilli lying parallel to the oocyte surface. In secondary follicles, patches of zona pellucida material were observed. Overall, the results indicate that the morphological and ultrastructural organization of caprine preantral follicles resembles that of other mammals. However, some particularities were observed, and that may indicate species specific differences

Erythema multiforme induced by alendronate sodium in a geriatric patient : a case report and review of the literature

Erythema multiforme is an uncommon acute inflammatory disorder caused by exposure to microbes or drugs. Erythema multiforme minor typically affects only one mucosa and can be associated with symmetrical target skin lesions on the extremities. The disease usually occurs in patients in their 3rd and 4th decade of life, but can also affect children and adolescents. Alendronate sodium has been approved for the prevention and treatment of osteoporosis in postmenopausal women, but is associated with adverse events. This study reports and discusses a case of erythema multiforme minor. In addition, a literature search of articles published in PubMed-Medline was performed. The case was a 96-year-old woman who had taken alendronate. Intraoral clinical examination demonstrated hypersalivation and macrocheilia of the lower lip, associated with an ill-defined ulcer with erythematous borders measuring 20 mm in greatest diameter and covered with serofibrinous exudates. The aging of the population in developed and developing countries has increased the use of alendronate sodium to prevent osteoporosis and clinicians should be aware of possible oral adverse events associated with this drug