REWE - Optimization of delivery channels in retailing

CEM

Domain walls in spin-valve nanotracks: characterisation and applications

Magnetic systems based on the manipulation of domain walls (DWs) in nanometre-scaled tracks have been shown to store data at high density, perform complex logic operations, and even mechanically manipulate magnetic beads. The magnetic nano-track has also been an indispensable model system to study fundamental magnetic and magneto-electronic phenomena, such as field induced DW propagation, spin-transfer torque, and other micromagnetic properties. Its value to fundamental research and the breath of potentially useful applications have made this class of systems the focus of wide research in the area of nanomagnetism and spintronics. This thesis focuses on DW manipulation and DW-based devices in spin-valve nanotracks. The spin-valve is a metallic multi-layered spintronic structure, wherein the electrical resistance varies greatly with the magnetisation of its layers. In comparison to monolayer tracks, the spin-valve track enables more sensitive and versatile measurements, as well as demonstrating electronic output of DW-based devices, an achievement of crucial interest to technological applications. However, these multi-layered tracks introduce new, potentially disruptive magnetic interactions, as well as fabrication challenges. In this thesis, the DW propagation in spin-valve nanotracks of different compositions was studied, and a system with DW propagation properties comparable to the state-of-the-art in monolayer tracks was demonstrated, down to an unprecedented lateral size of 33nm. Several DW logic devices of variable complexity were demonstrated and studied, namely a turn-counting DW spiral, a DW gate, multiple DW logic NOT gates, and a DW-DW interactor. It was found that, where the comparison was possible, the overall magnetic behaviour of these devices was analogous to that of monolayer structures, and the device performance, as defined by the range of field wherein they function desirably, was found to be comparable, albeit inferior, to that of their monolayer counterparts. The interaction between DWs in adjacent tracks was studied and new phenomena were observed and characterised, such as DW depinning induced by a static or travelling adjacent DW. The contribution of different physical mechanisms to electrical current induced depinning were quantified, and it was found that the Oersted field, typically negligible in monolayer tracks, was responsible for large variations in depinning field in SV tracks, and that the strength of spin-transfer effect was similar in magnitude to that reported in monolayer tracks. Finally, current induced ferromagnetic resonance was measured, and the domain uniform resonant mode was observed, in very good agreement to Kittel theory and simulations

Reproduction and cultivation of asparagopsis taxiformis (Delile) trevisan

Seaweeds have been receiving increased interest from the fisheries and aquaculture industries in recent years, with red algae continuing to be one of the more important components of seaweed aquaculture representing 54% of the harvested biomass (around US$ 6.3 billion). These seaweeds are important for both food and diverse of biotechnology usages. Asparagopsis taxiformis, a characteristic red alga, has been receiving increased attention for its biotechnological applications, the most interesting one being its ability to reduce methane emissions on the cattle. A. taxiformis presents a triphasic life history, passing from gametophyte to carposporophyte and finally to tetrasporophyte. The conditions for the lab manipulation and survival of this species are still not know, taking in consideration the difficulty of maintaining gametophyte cultures. In this work, some abiotic factors affecting gametophyte maintenance and reproduction were experimentally tested. A. taxiformis gametophyte did not survive any common pretreatment used, only surviving in culture if cleaned of epizoa in sterilized filtered seawater and by selecting the less epiphyted individuals. A. taxiformis showed the highest growth rate when cultivated at 15 ºC, not growing at 20 ºC and dying at 25 ºC. An industrial fertilizer used showed similar growth rates compared to the Von Stosch medium. Photoperiod manipulation did not result in any sexual differentiation on the gametophytes. A low stock density (1 g/L) was required since at higher densities there was reduced (2 g/L) or no (4g/L) growth rate. A. taxiformis was able to grow at both 20 and 40 μmol photon m-2 s-1, showing slightly higher (but not significant) growth rates at the latter. Attempts at inducing carposporophyte formation were unsuccessful. Temperature and light intensity were the two most important factors to maintain gametophyte culture.Os setores de aquicultura e pescas são importantes para a economia global. Nos últimos 30 anos, a aquicultura tem sido o principal responsável pelo aumento no fornecimento de peixe e algas para consumo. Cerca de 40 espécies de macroalgas são cultivadas no mundo, com um aumento substancial da sua produção registado nos últimos 20 anos. As algas marinhas têm várias utilizações desde alimentação, rações e a aplicações biotecnológicas. As algas vermelhas (Rhodophytas) têm, na sua maioria, um ciclo de vida trifásico, que consiste na alternância de fases entre gametófito, carposporófito e tetrasporófito. A Asparagopsis taxiformis, uma alga marinha vermelha, apresenta diversas utilidades culinárias e biotecnológicas e tem recebido um interesse especial a nível global pela sua capacidade de redução das emissões de metanos em gado bovino através do seu uso em rações. A. taxiformis apresenta o ciclo típico das algas vermelhas, sendo, no entanto ainda desconhecido os fatores bióticos e abióticos que levam às alternâncias de fase em laboratório. É sabido que as manipulações de fatores como a temperatura e fotoperíodo são comumente os principais fatores para indução de reprodução, enquanto que outros fatores abióticos como a qualidade da luz, a intensidade desta e a suplementação com nutrientes, são pontos importantes para a manutenção e possível manipulação dos ciclos de vida. Nos Açores, Asparagopsis spp. está presente anualmente, ocorrendo em maior biomassa durante os meses de primavera/inicio de verão. Tanto o gametófito como o tetraesporófito são encontrados no meio natural ao logo do ano. Com o interesse comercial crescente deste género, é necessário controlar o seu ciclo de vida in vitro para facilitar a sua produção. Este trabalho teve como objetivo definir os requerimentos para a manutenção do gametófito de A. taxiformis, incluindo vários fatores abióticos promotores de crescimento (pré-tratamentos; qualidade e intensidade de luz; temperatura; suplementação de nutrientes; fotoperíodo; e densidade de cultivo) e determinar os fatores que permitem a carposporogénese e a respectiva libertação de carpósporos in vitro. Os pré-tratamentos que são normalmente utilizados para a limpeza de espécimes de algas marinhas vermelhas, tiveram, na sua generalidade, efeitos adversos no cultivo desta espécie. Apenas a limpeza com pinças em banhos de água do mar filtrada e esterilizada, e a seleção de indivíduos com baixa presença de epífitos foram eficientes na manutenção do cultivo. Cultivos a temperaturas superiores a 20 ºC foram deletérios para o gametófito, que apenas registou taxas de crescimento positivas quando cultivada a 15 ºC. A A.taxiformis quando cultivada juntamente com a adição de um fertilizante habitualmente utilizado em cultivos de laboratório (Von Stosch) apresentou taxas de crescimento semelhantes aqueles registados quando cultivada com um fertilizante comercial, o que facilita o processo de cultivo. A exposição a diferentes fotoperíodos não resultou em diferenças nas características sexuais do gametófito durante o tempo de cultivo, mas a experiência foi interrompida por questões alheias ao cultivo, não tendo, por isto, os resultados sido conclusivos. Densidades de cultivo superiores a 1 g/L apresentaram taxas de crescimento mais reduzido, sendo que, à densidade de cultivo de 4 g/L as taxas de crescimento foram mesmo negativas para o gametófito. Por fim, o gametófito apresentou crescimento quando cultivado a 20 e a 40 μmol m-2 s-1, com taxas de crescimento ligeiramente maiores (embora não significativas) na última condição. Todas as tentativas de indução da formação de carposporófito e da sua maturação não foram bem-sucedidas. As duas variáveis testadas que mostraram maior importância na manutenção do cultivo do gametófito foram a temperatura e a intensidade de luz. Este trabalho conclui que é possível a manutenção em laboratório de A. taxiformis, tendo as condições ótimas observadas, dentro do leque de opções testadas, sido o seu cultivo a uma temperatura de 15 ºC, com uma intensidade de luz menor ou igual a 40 μmol m-2 s-1 e uma densidade de cultivo de 1 g/L. São necessários mais estudos para determinar as condições necessárias para a indução e maturação do carpoesporófito

The Effect of Genetic and Infrastructure Investments in Dairy and Beef Producers' Profit in Chile

The objective of this study was to evaluate the effect of infrastructure and genetic improvement investments, promoted by a government program (Programa de Modernizacion Ganadera), in milk and meat producers' profit in Region IX. Using a system of simultaneous equations, the effect of the investment on quality, in the price, in the yield and production cost of milk were estimated. In the case of milk, we reject the nonlinear hypothesis that the elasticities of investment in genetic improvement in gross income and variable costs are equal to zero. The estimation was done using information of 276 producers of the IX Region that participated in the program during the period 1998-99 (17,3 % of the regional population), with information for the years 1998 (baseline), 2001 and 2003. The results indicate that the investment in infrastructure had a positive and statistically significant impact in the quality of milk, which translates into a higher price received by producers. Meanwhile the investment in genetic improvement had a positive and significant effect in milk yield, but also in costs. Similar results were obtained for meat production, but the effect is weaker than in milk production, especially for infrastructure investments.Livestock Production/Industries, O13, Q14, Q16,

Vidros fosfatos funcionais para absorção de hidrogénio : preparação e caracterização

Mestrado em Engenharia FísicaOs vidros fosfatos têm potencial para atuar como catalisadores na dissociação de vapor de água em hidrogénio e oxigénio, possibilitando a adsorção de hidrogénio na sua superfície. A adição dos óxidos de nióbio e de sódio na sua composição, provoca uma despolimerização das ligações P-O-P características da rede dos vidros fosfatos, aumentando assim o número de oxigénios não ponte disponíveis para formar ligações O-H. A inclusão do óxido de tungsténio nestes sistemas vítreos, promove a oxidação dos átomos de hidrogénio em H+, que são absorvidos ao formarem ligações com os oxigénios não ponte. No presente trabalho, foram preparados vidros com as composições [ ( ) ] ( ) e (com A=Li, Na e K), através do método de fusão. Os vidros preparados foram tratados termicamente num forno a ar, a temperaturas de 500 °C, 600 °C, 700 °C, 800 °C e 1000 °C durante 4 horas com base nos resultados da análise térmica diferencial. A análise estrutural dos vidros obtidos foi realizada através das técnicas de difração de raios-X, espectroscopia de Raman, e pela determinação da densidade das amostras. Este estudo foi complementado pela observação da morfologia dos vidros pela técnica de microscopia eletrónica de varrimento. A análise da condutividade dc ( ), condutividade ac ( ) e propriedades dielétricas dos vidros (na gama de frequências 100- 1MHz), foi realizada em função da temperatura na gama 200-370 K e relacionada com a microestrutura das amostras.Phosphate glasses have potential to act as catalyst to dissociate water vapor into hydrogen and oxygen, and thus be able to capture hydrogen in its surface. The addition of sodium and niobium oxides to the glass composition, contributes to the depolymerization of the P-O-P chains increasing the number of non-bridging oxygen in the glass structure, whereas the tungsten plays a major role in the ability of dissociate and form hydrogen protons to bound with the non-bridging oxygen, and thus form OH groups. In the present work, glasses with a composition of [( ) ] ( ) and where A=Li, Na and K were prepared by the melt-quenching method. The as-prepared glasses were heat-treated in air, at 500 °C, 600 °C, 700 °C, 800 °C and 1000 °C for 4 hours based on the results from differential thermal analysis. The structure of these glasses was analyzed in function of the molar ratio between barium and strontium oxides. Structural studies were conducted by X-ray powder diffraction, Raman spectroscopy, and density measurements, whereas the bulk and fracture morphology was analyzed by scanning electron microscopy. dc ( ), ac ( ) conductivity and dielectric spectroscopy (100-1MHz) measurements were performed in function of the temperature (200-370 K) and related with their microstructure

Regarding value in digital serendipitous interactions

Digital technologies have become our privileged method of interacting with information. With their ubiquity, and focus on personalisation, optimisation and functionality, chance and accidental interactions in the Digital Medium are being replaced with filtered, predictable and known ones, limiting the scope of possible user experiences. In order to promote the design of richer experiences that go beyond the functionally-driven paradigm, we propose that digital systems be designed in order to favour serendipity. Through a literature-based analysis of serendipity, we explore the distinct meanings of value that are possible with serendipitous systems, offering examples of the current state of the art, observing the methods used to do so, and proposing a possible typology, while highlighting unexplored fields, experiences and interactions.&nbsp

Wearable Integrated Devices for Sustainable Energy: Self Powered e-Cloths

Nowadays, from lifestyle to sports and health to security, wearable technology is an inevitable trend that, through the human-machine interaction, has the capability of transforming businesses by making them smarter, more informative, and more communicative. In this study, commercial textile fibers have been functionalized with Polypyrrole (PPy) to achieve an electronic system that can convert external mechanical energy into electrical energy. PPy is a biocompatible π-conjugated polymer. The main principle behind the devices’ operation is the charge transfer mechanism that occurs between the π-conjugated polymer and the metal (electrode) layer when the system suffers mechanical stress. Furthermore, the PPy functionalized textile has been weaved to an e-cloth, through a custom-built weaving machine. This e-cloth can generate current under human-motion interaction. The best results achieved in this study, in terms of power density and current density, were 2.29 Wm-2 and 23.9 mA m-2 , respectively. Considering the best device, we were able to light up to 50 LEDs connected in series. With this device, we were also able to charge a 33F capacitor up to 1V, in 225 seconds. All the devices built have kept electrical stability during the six months of the work. The main application explored in this study was the detection of human movements through motion interactive energy harvesting technology

A pilot welfare assessment study in three captive african elephants (Loxodonta africana) at Barcelona zoo

Dissertação de Mestrado Integrado em Medicina Veterinária. Área Científica em que se enquadra: ClínicaThe welfare of wild animals in captivity is an increasingly discussed topic these days. The African elephant (Loxodonta africana) is an intelligent, charismatic animal, with specific social and environmental needs. The species L. africana is currently considered endangered by the International Union for Conservation of Nature. The decreasing number of individuals in the wild is mainly due to poaching for ivory. African elephants housed in captivity act as ambassadors for their wild counterparts, enabling the research on factors that may impact health, longevity, or reproduction, that may be extrapolated to wild populations. Hence, the importance of studying and promoting the welfare of these animals in man-made environments is highlighted. This study sought to develop a tool to assess the welfare of three adult female African elephants (E1, E2, and E3) housed at Barcelona Zoo, Spain. For this purpose, saliva samples were collected on a daily basis to measure cortisol, as well as behavioral observations, between October and December 2018. Salivary cortisol is increasingly used when studying changes in animal welfare. It is considered an effective method for quantifying cortisol levels, capable of detecting acute stress fluctuations, in addition to being a less invasive method than measuring cortisol in the blood. The objectives of this study were to establish baseline cortisol values for the three individuals of the species L. africana, and to explore the relationship between salivary cortisol and stereotypic behavior, specifically head bobbing. Saliva cortisol values ranged from 0.123 to 3.307 ng/ml. The results showed that the animal with the highest mean cortisol, E3, also corresponded to the animal that had a higher rate of stereotypic behaviors. However, the positive correlation between cortisol and head bobbing was not statistically significant (p-value = 0.71). During the study period, a change in the hierarchy was observed among the three elephants based on the analysis of social behaviors. In terms of agonistic behaviors, E2 faced E3 a total of 50 times. In addition, these animals allocate a large part of their time foraging. This pilot study contributes to increasing the psychological well-being of elephants in captivity by elucidating which factors influence well-being and stereotypic behavior. Projects of this nature are essential for the proper management of these magnificent animals in captivity.;RESUMO - O bem-estar de animais selvagens em cativeiro é um tema muito debatido atualmente. O elefante Africano (Loxodonta africana) é um animal inteligente e carismático, com necessidades sociais e ambientais específicas. Presentemente, a espécie L. africana encontra-se em perigo, segundo a União Internacional para a Conservação da Natureza, sendo a caça furtiva para venda de marfim considerada a principal razão para a diminuição do número de indivíduos em estado selvagem. Os elefantes africanos em cativeiro atuam como embaixadores dos seus congéneres selvagens, possibilitando o estudo de fatores que podem afetar a sua saúde, longevidade ou reprodução, podendo ser extrapolados para populações selvagens, o que reforça a importância de estudar e promover o bem-estar destes animais em ambientes artificiais. Este estudo focou-se no desenvolvimento de uma ferramenta de avaliação do bem estar em três elefantes Africanos adultos (E1, E2 e E3), fêmeas, alojados no Jardim Zoológico de Barcelona, Espanha. Foram realizadas diariamente colheitas de saliva para medição de cortisol, assim como observações de comportamento, entre outubro e dezembro de 2018. O cortisol salivar é muito utilizado no estudo das alterações do bem-estar animal. É um método eficaz para quantificar os níveis de cortisol, capaz de detetar flutuações agudas de stress, além de ser menos invasivo do que a medição de cortisol no sangue. Os objetivos deste estudo foram estabelecer valores basais de cortisol dos três indivíduos da espécie L. africana, e investigar a relação entre os valores de cortisol salivar e comportamentos estereotipados, nomeadamente head bobbing. Os valores de cortisol na saliva variaram entre 0.123 to 3.307 ng/ml. O animal com a média de cortisol mais elevada, E3, correspondia também ao que apresentava uma maior taxa de comportamentos estereotipados. No entanto, a correlação positiva entre o cortisol e head bobbing não foi estatisticamente significativa (p-value = 0.71). Neste período, observou se uma alteração na hierarquia entre os três elefantes, com base na análise dos comportamentos sociais. Em termos de comportamentos agonísticos, E2 enfrentou E3 num total de 50 vezes. Além disso, foi possível observar que estes animais alocam grande parte do seu tempo ao consumo de alimentos. Este estudo piloto contribui para o aumento da avaliação e conhecimento do bem-estar psicológico dos elefantes em cativeiro, ao elucidar que fatores influenciam o bem-estar e o comportamento estereotipado. Projetos desta natureza são essenciais para um maneio adequado destes magníficos animais em cativeiroN/

Automated illustration of multimedia stories

Submitted in part fulfillment of the requirements for the degree of Master in Computer ScienceWe all had the problem of forgetting about what we just read a few sentences before. This comes from the problem of attention and is more common with children and the elderly. People feel either bored or distracted by something more interesting. The challenge is how can multimedia systems assist users in reading and remembering stories? One solution is to use pictures to illustrate stories as a mean to captivate ones interest as it either tells a story or makes the viewer imagine one. This thesis researches the problem of automated story illustration as a method to increase the readers’ interest and attention. We formulate the hypothesis that an automated multimedia system can help users in reading a story by stimulating their reading memory with adequate visual illustrations. We propose a framework that tells a story and attempts to capture the readers’ attention by providing illustrations that spark the readers’ imagination. The framework automatically creates a multimedia presentation of the news story by (1) rendering news text in a sentence by-sentence fashion, (2) providing mechanisms to select the best illustration for each sentence and (3) select the set of illustrations that guarantees the best sequence. These mechanisms are rooted in image and text retrieval techniques. To further improve users’ attention, users may also activate a text-to-speech functionality according to their preference or reading difficulties. First experiments show how Flickr images can illustrate BBC news articles and provide a better experience to news readers. On top of the illustration methods, a user feedback feature was implemented to perfect the illustrations selection. With this feature users can aid the framework in selecting more accurate results. Finally, empirical evaluations were performed in order to test the user interface,image/sentence association algorithms and users’ feedback functionalities. The respective results are discussed

Três mitos visuais de Braga: um ensaio em geografia cultural

Trata-se de um ensaio em geografia cultural do espaço urbano, onde são fixados três mitos da cidade de Braga, neste caso, analisados a partir das referências visuais veiculadas pelos postais ilustrados. Este texto resulta ainda de um projecto apoiado pela FCT na área das ciências da comunicaçãoFCT/CECS/CICS/CITCE