Efeito da proteína anticongelante tipo I (AFP I) na criopreservação de embriões e blastómeros de teleósteos

Dissertação de mest., Biologia Marinha, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2007

Análise de sistemas de comunicação óptica com multiplexagem de subportadora e transmissão em banda lateral única

Tese dout., Engenharia Electrónica e Computação, Universidade do Algarve, 2005

Endocrine regulation of extracellular matrix proteins in calcified tissue in teleost fish

Tese dout., Biologia, Universidade do Algarve, 2005

Characterization of pro- and anti-angiogenic factors in models of diabetic retinopathy

Dissertação de mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2015

Contribuições para a deteção automática de fratiras ósseas em imagens de ultrassom

Dissertação de Mestrado, Engenharia Eletrónica e Telecomunicações, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2014

Levantamento preliminar dos nemátodes anisaquídeos presentes no Gorz, Pagellus bogaraveo, (Br nnich, 1768), no estado selvagem na Região Autònoma da Madeira

Dissertação de mest. em Aquacultura, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2001

A influência das tecnologias de informação e de comunicação na procura turística: uma abordagem com dados em macro panel

Tese de Doutoramento em Métodos Quantitativos Aplicados à Economia e à Gestão, Especialização em Econometria, Universidade do Algarve

La duplicitat d'objectes mágics a la història d'Aladdín i a una rondalla d'Antoni M. Alcover

A história de Aladino, tal como aparece em muitas edições de As Mil e uma Noites, contém uma particularidade que a afasta das leis da economia do conto popular, em relação às quais se mostra um tanto incoerente: a presença de dois objectos mágicos com poderes ilimitados: o anel e a lâmpada. As versões do conto que achamos em As Mil e uma Noites são muito literárias, mas no seu conteúdo podemos reconhecer o tipo 561 do Índice de Aarne-Thompson. A versão de Galland, da qual poderiam derivar todas as outras, até as dos textos redigidos em árabe, procede de Hanna Diab,que lhe deu uma versão escrita. Uma versão desse tipo, recolhida por Antoni M. Alcover da tradição oral de Maiorca, também contém a duplicidade de objectos mágicos. Charlotte R. Long viu no primeiro episódio do conto de Aladino o rasto do roubo dum túmulo egípcio; na versão de Alcover, dentro da caverna onde o herói acha a lâmpada, há um cadáver,detalhe que a torna singular.

Design of neuro-fuzzy models by evolutionary and gradient-based algorithms

All systems found in nature exhibit, with different degrees, a nonlinear behavior. To emulate this behavior, classical systems identification techniques use, typically, linear models, for mathematical simplicity. Models inspired by biological principles (artificial neural networks) and linguistically motivated (fuzzy systems), due to their universal approximation property, are becoming alternatives to classical mathematical models. In systems identification, the design of this type of models is an iterative process, requiring, among other steps, the need to identify the model structure, as well as the estimation of the model parameters. This thesis addresses the applicability of gradient-basis algorithms for the parameter estimation phase, and the use of evolutionary algorithms for model structure selection, for the design of neuro-fuzzy systems, i.e., models that offer the transparency property found in fuzzy systems, but use, for their design, algorithms introduced in the context of neural networks. A new methodology, based on the minimization of the integral of the error, and exploiting the parameter separability property typically found in neuro-fuzzy systems, is proposed for parameter estimation. A recent evolutionary technique (bacterial algorithms), based on the natural phenomenon of microbial evolution, is combined with genetic programming, and the resulting algorithm, bacterial programming, advocated for structure determination. Different versions of this evolutionary technique are combined with gradient-based algorithms, solving problems found in fuzzy and neuro-fuzzy design, namely incorporation of a-priori knowledge, gradient algorithms initialization and model complexity reduction.

Electrical characterization of metal-oxide-polymer devices for non-volatile memory applications

The objective of this thesis is to study the properties of resistive switching effect based on bistable resistive memory which is fabricated in the form of Al2O3/polymer diodes and to contribute to the elucidation of resistive switching mechanisms. Resistive memories were characterized using a variety of electrical techniques, including current-voltage measurements, small-signal impedance, and electrical noise based techniques. All the measurements were carried out over a large temperature range. Fast voltage ramps were used to elucidate the dynamic response of the memory to rapid varying electric fields. The temperature dependence of the current provided insight into the role of trapped charges in resistive switching. The analysis of fast current fluctuations using electric noise techniques contributed to the elucidation of the kinetics involved in filament formation/rupture, the filament size and correspondent current capabilities. The results reported in this thesis provide insight into a number of issues namely: (i) The fundamental limitations on the speed of operation of a bi-layer resistive memory are the time and voltage dependences of the switch-on mechanism. (ii) The results explain the wide spread in switching times reported in the literature and the apparently anomalous behaviour of the high conductance state namely the disappearance of the negative differential resistance region at high voltage scan rates which is commonly attributed to a “dead time” phenomenon which had remained elusive since it was first reported in the ‘60s. (iii) Assuming that the current is filamentary, Comsol simulations were performed and used to explain the observed dynamic properties of the current-voltage characteristics. Furthermore, the simulations suggest that filaments can interact with each other. (iv) The current-voltage characteristics have been studied as a function of temperature. The findings indicate that creation and annihilation of filaments is controlled by filling and neutralizing traps localized at the oxide/polymer interface. (v) Resistive switching was also studied in small-molecule OLEDs. It was shown that the degradation that leads to a loss of light output during operation is caused by the presence of a resistive switching layer. A diagnostic tool that predicts premature failure of OLEDs was devised and proposed. Resistive switching is a property of oxides. These layers can grow in a number of devices including, organic light emitting diodes (OLEDs), spin-valve transistors and photovoltaic devices fabricated in different types of material. Under strong electric fields the oxides can undergo dielectric breakdown and become resistive switching layers. Resistive switching strongly modifies the charge injection causing a number of deleterious effects and eventually device failure. In this respect the findings in this thesis are relevant to understand reliability issues in devices across a very broad field.

Recruitment patterns and processes of coastal fish species in a temperate rocky reef

Tese de Doutoramento, Ciências do Mar, da Terra e do Ambiente, Ramo: Ciências do Mar, Especialização em Ecologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016