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Browsing by Issue Date, starting with "2020-11-18"

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  • Características psicométricas da versão portuguesa da Escala de Satisfação Marital ENRICH
    Publication . Leal, Andreia Patrícia Lima de Carvalho; Nunes, Cristina
    A satisfação marital tem uma enorme importância nas relações familiares com consequências diretas na vivência da parentalidade. Este estudo tem como objetivo analisar as características psicométricas da versão portuguesa da Escala de Satisfação Marital ENRICH, analisar a validade convergente do instrumento com medidas do funcionamento familiar e a validade discriminante do mesmo com medidas de stresse parental. O estudo contou com uma amostra de 205 famílias residentes no Algarve, com filhos com idades compreendidas entre 1 e 13 anos de idade. Os resultados confirmaram uma estrutura bifatorial do modelo e uma boa consistência interna (α = ,87) tendo havido a necessidade de ajustar o modelo. Observámos uma relação significativa e positiva entre a satisfação marital e a aliança parental e uma relação significativa e negativa com o stresse parental. Os resultados obtidos na análise fatorial confirmatória suportaram a utilização do instrumento na avaliação da satisfação marital na população portuguesa.
    2020-11-18Master thesis Open access Show more
  • Para onde ir, onde ficar e o que fazer? Como decidem os turistas da geração Z
    Publication . Silvério, Lais Carine Martins de Brito; Santos, Margarida C.; Santos, José António C.
    Com demandas específicas e ocupando cada vez mais espaço no mercado turístico, a Geração Z constitui um público com imenso potencial, mas ainda pouco analisado pela ótica do setor. A presente dissertação tem como objetivo entender o perfil dessa geração no contexto do turismo, principalmente no que envolve suas decisões de para onde viajar, como escolher o alojamento e que atividades realizar no destino. A revisão de literatura se desenvolve na busca por conhecer as características gerais dessa geração, seus comportamentos e expectativas enquanto consumidores, até entender como atuam no âmbito do turismo. Além disso, através da recolha de dados primários foi possível fazermos uma análise comparativa entre as respostas de 1002 jovens da Geração Z residentes em Portugal e no Brasil para investigar se há similaridades entre a mesma geração dos dois países. A pesquisa bibliográfica aliada ao estudo empírico nos permitiu evidenciar traços marcantes dessa geração, bem como concluir que apesar de existirem diferenças resultantes do contexto de cada país, há padrões comportamentais que ultrapassam as barreiras geográficas e marcam o perfil desses jovens turistas.
    2020-11-18Master thesis Open access Show more
  • Bio-electronic transducers to interact with cancer cells
    Publication . Brázio, Diogo Luzia; Gomes, Henrique L.
    This thesis is focused on the study of electrophysiological signals in populations of cancer cells measured using extracellular electrodes. The cells under study are derived from cells known as glia cells. Glia cells are part of the brain but are significantly different from neurons. An important function of glia cells is to regulate communication between neurons. Glia cells can mutate and turn into cancer cells. When this happens, they give rise to very aggressive tumors (gliomas). The study of electrophysiological signals in cells of this type is relevant because in principle it can give information about how this type of cells is organized and communicates to perform simple tasks, such as migrating or proliferating. In contrast to neurons, or cardiomyocytes, glia cells do not generate action potentials and therefore, are included in the class of non-electrogenic cells. However, glia cells have developed an information transmission mechanism that is based on the generation of a local ionic oscillation. This oscillation can travel to neighboring cells like a wave. To generate the oscillation, the cells generate a flow of ions, for example of calcium or sodium ions, the associated electrical oscillations are known as calcium or sodium waves, respectively. Ionic oscillations can travel long distances (millimeters). For the oscillation to travel through the cell population, cells must be connected to form a compact biological tissue. The formation of the wave also requires that the cells have the ability to synchronize their activity. Unlike an action potential, that is an oscillation generated by an individual cell, the oscillations generated by glia cells are a property of a set of cells that synchronize to generate electrical fluctuation. Note that both the action potential and the wave generated by the glia cells are both electrical signals that travel like waves. However, there are important differences in the characteristics of the two signals. An action potential is a fast signal (meters / s) and short duration (milliseconds). A calcium wave is an oscillation that can last for several seconds and propagates through the population of cells at speeds of a few tens of micrometers per second. A calcium wave is typically a thousand times slower than an action potential. The measurement and interpretation of action potentials using extracellular electrodes is well documented in the literature. As for the electrical waves generated by the synchronized activity of cells, the knowledge is very poor. Until now, this type of bio-electrical signaling mechanism has been studied using optical markers and fluorescence techniques. Although, optical techniques can visualize the wave, they suffer from a set of limitations, both from experimental as well as from a biological point of view. For example, optical markers have a relatively short lifetime (hours), and can be toxic to cells. Additionally, light can disturb the measurements. Optical florescence has in its favor the fact that it is a selective technique and allows to know exactly the ionic species that is involved in the process. Electrical techniques cannot differentiate which ion is involved, but they can observe oscillations in real time in a totally noninvasive way and for extended periods (weeks or months). The existing literature on the signal analysis and processing of signals that are result from synchronized cell activity is practically non-existent. This scientific area is still in its infancy. This thesis aims to contribute to increase our knowledge about this type of bio-electric signaling. The objective of the work presented in this thesis was to study how the design of extracellular electrodes determines the shape of the measured electrical signal. Since the signal is an electric wave that travels through the cell population, it is obvious that the shape of the signal is essentially determined by a number of factors, namely the; (i) number of cells that are able to synchronize, (ii) electrode design, (iii) electrode active area, and even (iv) spatial arrangement of the electrodes in relation to the wave propagation direction. This study processed a large number of signals collected using electrodes with different areas and geometries. The signals were first cataloged and classified according to the shape of the measured signal. Then, relationships were established between the power of the measured signal and the active area of the measured electrode, the periodicity of the signal and the spacing of the sensor electrodes. The components of the signal that vary exponentially have been quantified to determine the physical origin of the exponential behavior, or in other words if it originates in a biological process or if it is determined by the time constant (physics) of the electrode. Finally, several signal patterns were characterized and classified. Among the most interesting patterns, a pattern in which the frequency increases following an exponential law (called a blueshift) and a pattern where the frequency decays exponentially (redshift) were observed. The results of the signal analysis and their relationship with the geometry of the electrodes allowed us to quantify the role of the electrode in defining the shape and the duration of the signal. Guidelines for the optimization of the electrodes was also an important outcome of this thesis. Finally, it is important to note that from the biological point of view it is expected that the optimization of the electrodes will allow to decode signaling patterns that correspond to specific biological instructions. For example, assuming that cell migration is a process instructed by an electrical oscillation with a certain pattern, decoding this pattern will eventually enable us to inhibit cell migration, thus paving the way for new technologies for cancer therapy. The limitations of using radiotherapy and chemotherapy in the brain make electrical techniques particularly appealing to treat brain tumors.
    2020-11-18Master thesis Open access Show more
  • Otimização da aplicação comercial - concept SPA & leisure
    Publication . Miguel, Aristides Fausto Rosa; Lam, Roberto; Schutz, G.
    The applications dedicated to the spa and leisure are in huge demand due to the latter growth in developed countries. This type of application has been designed to manage activities at hotels, health spas and leisure venues. Usually, appointments are booked quickly and efficiently via a series of flexible grid control screens or through an availability search, where the system automatically finds available times. This project presents a solution to the problem of SPA & Leisure (SPA) application. Nowadays it generates thousands of records daily, which leads to increase data on the database. Currently, the application is facing a performance challenge due to the amount of data involved in the booking process. The objective of the present work is to propose a dedicated notification framework to optimize the SPA application. The main goal of this framework model is to reduce traffic on the network between the client application and database server. This would be achieved by using as much as possible data stored locally, rather than requesting it from the database every time it is needed. The search engine process is speeded up, keeping as many data as possible within the client application. A message broadcast framework will be created to maintain local data synchronized with the database. The main idea is to have a parallel system to keep watching data changes on the database and as soon as data change, a message will be sent to processes to inform that current data held is out-of-date and must be refreshed before use in the client application. In the meantime, the Message Broadcast Framework was implemented. The tests performed and the analysis of their results, are presented in Chapter 5.
    2020-11-18Master thesis Open access Show more