Simulations of Antigenic Variability in Influenza A

Computational models of the immune system (IS) and pathogenic agents have several applications, such as theory testing and validation, or as a complement to first stages of drug trials. One possible application is the prediction of the lethality of new Influenza A strains, which are constantly created due to antigenic drift and shift. Here, we present several simulations of antigenic variability in Influenza A using an agent-based approach, where low level molecular antigen-antibody interactions are explicitly described. Antigenic drift and shift events are analyzed regarding the virulence of emergent strains against the IS. Results are discussed from a qualitative point of view taking into account recent and generally recognized immunology and influenza literature

Cultural accessible pedestrian ways. The case of Faro historic centre

In a historic city the existence of accessible pedestrian routes constitutes an essential feature to a true access to culture heritage, contributing for processes of social inclusion. It is necessary to create accessible pedestrian infrastructures network to hold a set of attributes that guarantee usability for all citizens. The creation and design of an accessible physical environment should be considered as a criterion of urban quality, which will make walking more pleasant not only for the elderly and people with disabilities but, also, for the entire resident population and tourists. In this case study it is ascertainable whether the physical characteristics of pedestrian infrastructures of cultural interest, located in the Historical Centre of Faro (Portugal), comply with the requirements of the National Law of Accessibility. There has, therefore, been created a methodology for evaluating the accessibility of pedestrian infrastructure through the construction of performance indicators. The analysis is achieved through a model of evaluation of the degree of conformity of the spaces, and presented, spatially, with appeal to a Geographical Information System, which is a tool to support the decision taking in the processes of urban rehabilitation, thus contributing to the choice of priority areas of intervention in the field of accessibility. The diagnosis confirms the existence of inaccessible pedestrian infrastructure and concludes the need to trigger processes of urban renovation.info:eu-repo/semantics/publishedVersio

Influence of collagen fibril alignment in collagen scaffolds mineralization

Bone extracellular matrix (ECM) gives bone its unique mechanical properties, thus being important in bone tissue engineering to mimic its native composition and microstructure. The main component in bone ECM is Type-I collagen, which works as a scaffold for bone cell attachment and mineral deposition. There are two locations where mineralization takes place: the intrafibrillar and interfibrillar spaces of collagen fibrils. Several theories try to explain mineral formation in bone tissue. However, none of them was proven right, and so, the mechanism for mineralization facilitated by the collagen lattice is still unknown. This way, it is essential to study such a mechanism and develop bone tissue engineering approaches to mimic bone ECM. In this work, we hypothesized that collagen fibrils alignment would promote scaffolds mineralization. To prove it, we 3D printed fibrillar collagen hydrogels scaffolds using the suspension 3D printing technique, in which a gelatin slurry was used as a suspension bath. First, an optimization of the printing process was performed. Then scaffolds were printed, choosing the finest (123 ± 25 µm) and largest fiber diameter (215 ± 66 µm) obtained. Fiber diameter size was proven to affect the collagen fiber alignment inside the scaffolds and, consequently, affect mineral precipitation. The smallest fiber diameter scaffold showed signs of mineralization after one day inside a mineralization solution. In contrast, the largest fiber scaffold only presented mineralization signs after three days of submersion. Moreover, suspended electrowriting was introduced in this dissertation, obtaining a 40 µm jet diameter inside a castor oil bath, proving to be a promising additive manufacturing technology to achieve higher resolution constructs when 3D printing hydrogels.A matrix extra celular (ECM) do osso confere-lhe as suas únicas propriedades mecânicas e, portanto, torna-se importante mimetizar a composição e microestrutura nativa da ECM em engenharia de tecidos ósseos. O colagénio tipo-I é o principal componente da ECM e funciona como suporte para adesão celular e deposição de minerais, podendo a mineralização ocorrer nos espaços Intra e interfibrilares do colagénio. Existem algumas teorias que tentam explicar os mecanismos de formação de minerais no tecido ósseo. Contudo, nenhuma foi comprovada, fazendo com que, o mecanismo pelo qual a mineralização facilitada por colagénio ocorre, seja ainda desconhecido. Desta forma, estudar este mecanismo e desenvolver técnicas, em engenharia de tecidos, para que seja possível mimetizar a ECM do osso, torna-se essencial. Neste projeto, teorizámos que o alinhamento das fibrilas de colagénio em scaffolds iriam promover a sua mineralização. Deste modo, hidrogéis de colagénio fibrilar foram impressos recorrendo à técnica de impressão em suspensão, na qual foi utilizado um banho de suspensão à base de gelatina. Inicialmente, a otimização do processo de impressão foi efetuada. De seguida, as fibras mais estreitas (123 ± 25 µm) e largas (215 ± 66 µm) foram escolhidas para realizar a impressão das estruturas desejadas. Foi provado que o diâmetro das fibras influencia o alinhamento das fibrilas de colagénio nas estruturas e, consequentemente, a sua mineralização. As fibras de menor dimensão apresentaram sinais de mineralização após um dia de submersão na solução de mineralização, enquanto que, as fibras mais largas exibiram sinais de deposição de minerais apenas após três dias. Adicionalmente, a técnica de suspended electrowriting foi introduzida nesta dissertação, obtendo-se um diâmetro de jato de 40 µm dentro de um banho de óleo de ricínio, provando que esta é uma técnica promissora de fabrico aditivo, que nos permite atingir melhores resoluções na impressão 3D de hidrogéis

New Physics in the Electroweak Sector Under Scrutiny at LHC

[eng] For more than half a century, colliders have been in the forefront of studying the Standard Model (SM) predictions. The pinnacle of both SM and colliders occurred when on July the 4th 2012, at CERN Large Hadron Collider, the Higgs discovery was announced, almost 50 years after being postulated. Until 2012 the Higgs was the only missing piece of the SM, and its discov- ery was a milestone in the LHC. The complete analysis of Run 1 data and the preliminary ones from Run 2 data, indicate that this new particle is a scalar bo- son, with CP–even properties, as in the SM Higgs scenario. Furthermore, it seems that the observed state is directly connected to the electroweak symmetry breaking (EWSB), after analyzing interactions with gauge bosons. Until the moment there is no evidence of any physics BSM at the LHC in the form of new states. Clearly this disfavours any extension of the SM that predicts new particles at the TeV scale. This was the scenario when this Thesis was initiated. The Run 1 of LHC had reached its final luminosity, and the Run 2 was starting its operation. The lack of NP states at LHC served us as motivation to look for an alternative approach, instead of constraining ourselves to an specific SM completion. Here enters the model-independent philosophy, where through the use of an effective Lagrangian we start to confront all the existing available data and search for any possible de- viation of the SM predictions, by making use of the framework of Effective Field Theories (EFT). In the context of an EFT, we follow an atheist path: NP is expected to manifest directly at a scale Λ, which is higher than the scale at which the experiments are performed. Any effect of new physics (NP) at the low scale can be parametrized by a set of higher dimensional operators, that are suppressed by powers of the high energy scale. With this aim, in Chapter 2 we introduce the SM as an EFT at low energy. Our ignorance about the ultraviolet (UV) theory, and with no guidance of where the scale of NP could be laying, lead us to a bottom-up approach, where the higher dimensional operators used are driven by the existing data on the EW sector. This Chapter is supposed to set the roots of the analysis done in Chapters 3, 4 and 5. The results presented in these Chapters represent a step in the determination of the precision at which the different interactions in the EW sectors of the SM are being tested by the available data. The ultimate purpose of these analyses is to look for deviations that would be translated in the future on information regarding the UV completion of the SM. Up to this point our focus was on the scrutiny of the EWSB at LHC, and so the origin of the particles’ mass from a model-independent point of view. But still there are other alternatives to study physics beyond the SM, like direct searches at the LHC for some particular signature in a model. Clearly this approach only applies to neutrino models which are testable at LHC. In Chapter 6 we will study one such model of Type-III see-saw where the heavy states can live in the TeV region and, not less important, the couplings of these states are determined by the light neutrino masses and mixings.[spa] Esta tesis se centra en la búsqueda de física mas allá del modelo estándar en el sector electrodébil, y en particular en el mecanismo de la rotura expontánea de la simetría electrodébil y de la generación de masas, usando datos recogidos por los experimentos del Large Hadron Collider. El zenit, tanto del modelo estándar como de la física experimental de colisionadores se alcanzó en 2012 cuando CERN anunció el descubrimiento de una nueva partícula que podría ser el boson de Higgs. Hasta 2012 el boson de Higgs era la única pieza que faltaba en la construcción del modelo estándard. Sin embargo, sabemos de forma feaciente que el modelo estándar no puede ser la teoría de la Naturaleza basandonos en hechos puramente observacionales tales como la existencia de materia oscura, de neutrinos masivos, y de la simetría materia-antimateria en el Universo. En particular, la falta de nuevos estados observados en el LHC nos sirvió como motivación para el uso de Lagrangianos efectivos como herramienta para testear en una forma independiente de modelo una amplia variedad de datos con el fin de buscar posibles desviaciones sobre las predicciones del modelo estándar. En este contexto, los efectos de nueva física, que se manifestarían de forma directa a una escala Lambda superior a aquella alcanzable en los experimentos estudiados, pueden parametrizarse en una serie de operadores de dimensión mayor que cuatro y que aparecen en el Lagrangiano suprimidos por potencias de Lambda. Para ello el capítulo 2 tras una breve introdución sobre como se construye una teoría efectiva. En los siguientes tres capítulos 3–5 presentamos un análysis en que el objetivo es buscar desviaciones de las predicciones del modelo estándar que pudieran darnos información sobre el modelo completo en el sector responsable para la generación de masas. Finalmente en el capítulo 6 presentamos los resultados de un estudio realizado en el contexto de un modelo de masa de neutrinos. Dado que el LHC es nuestra principal herramienta para testear las extensiones del modelo estándar, una cuestión obvia es si LHC puede darnos información acerca de las extensiones que permiten generar masas para los neutrinos

Portugal as an European destination reference in senior tourism

O presente projeto consiste na determinação estratégica relativa ao desenvolvimento de Portugal cujo objectivo central é determinar de que forma Portugal pode vir a ser um player de referencia no contexto de Turismo Sénior, um segmento de mercado que representa já, quer em volume quer em valor o mais atrativo segmento de turistas. À medida que a população mundial envelhece, o segmento sénior é considerado o segmento de consumo mais valioso, um fenómeno que se verifica não só na indústria do turismo, mas é sim comum a todas as indústrias. Este segmento possui atualmente tempo e capital disponível para a prática de turismo. Todos os dias 10,000 novos cidadãos Americanos entram na idade da reforma. Para além disso, aqueles considerados “Baby- Boomers” e que detêm hoje cerca de 60% de toda a fortuna mundial, serão os próximos “seniores” e irão dominar a indústria mundial do Turismo exigindo uma oferta cada vez mais adaptada às suas necessidades. Posto isto, é urgente o desenvolvimento de uma estratégia direcionada não só aos membros da atual população sénior mas também a outras gerações, nomeadamente os “Baby-Boomers” e a Generation X que irão representar a curto/médio prazo o segmento “sénior” da população mundial. De forma a fazê-lo de uma forma eficaz, é crucial ter em conta a necessidade de criar uma ligação emocional com estes grupos de consumidores, ao mesmo tempo que a oferta turística disponível deverá ser capaz de se desenvolver e adaptar de forma contínua à evolução das suas necessidades e comportamentos turísticos.The presented project consists in a strategic development of Portugal as a Touristic Destination witch major goal is to understand how can Portugal become a major Player in Senior Tourism, as segment of the population that already represents both in volume and value the most attractive travel segment. With the increasing ageing of the world’s population, seniors are pointed out to become the most valuable consumer segment. These have increasing available time to travel and they have the disposable income to spend in travel experiences as a primary motivation. Every day in the USA 10,000 people enter in the retirement age, a trend that is expected to prevail until 2020. Moreover, 60% of the world’s fortune lies in the hands of baby-boomers, which will soon become the next seniors, dominating the World tourism and demanding hand-crafted experiences as never before. A Destination that is able to understand their needs and develop customized experiences to fit their demand will surely hold a valuable competitive advantage. This being said, there was the needed to develop a strategy targeted not only to those who may be already considered “seniors”, but also to the other generations namely Baby- Boomers and members of Generation X that will become “seniors” in a 10 to 20 year period. In order to do it effectively, this strategy must take into account the need to create an emotional connection with those consumers, while our touristic offer must be developed and continuously adapted to their evolution in terms of needs and travel behaviours

The cultural models in international business research: A bibliometric study of IB journals

Culture has been a widely researched topic in the International Business (IB) literature over the last decades. To better understand what culture actually means and its implication in firms? IB operations, several cultural models and taxonomies have been put forward. In this paper we seek to scrutinize the use of three well known cultural models - Hall?s (1976), Hofstede?s (1980a) and Trompenaars & Hampden-Turner?s (1993) - in the extant research. Using bibliometric techniques of the papers published in the top ranked IB journals, we performed a citation and co-citation analysis to find out the most influential model and to examine the possible linkages between models and to the issues being researched. We conclude that Hofstede?s (1980a) taxonomy is the most cited and his taxonomy has strong linkages to several streams of research. Nonetheless, we also find that there are noticeable differences on how research in different journals make use of the cultural models, probably reflecting not surprising disciplinary emphases.Cultural models, Hofstede, Trompenaars, Hall, bibliometric study