5,391 research outputs found

    A comunicação e as teorias narrativas

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    This is a review of the book Diccionario de Teorías Narrativas 2: narratología, cine, videojuegos, medios, edited and organized by the Spanish Professor Lorenzo Vilches Manterola, Emeritus of the Universidad Autónoma de Barcelona (UAB), launched in 2021, in printed and ebook format, by the publisher Caligrama, in Spanish language. The book, organized in the form of a dictionary, has approximately 450 entries (verberts) that bring to light not only fundamental concepts regarding contemporary Narrative Theories, but also applications and methodologies that relate to narratology, the media and communication.Trata-se de uma resenha do livro Diccionario de Teorías Narrativas 2: narratología, cine, videojuegos, medios, editado e organizado pelo espanhol Lorenzo Vilches Manterola, Professor Catedrático e Emérito da Universidad Autónoma de Barcelona (UAB), lançado em 2021 em formato impresso e ebook pela editora Caligrama, em língua espanhola. A obra, organizada em forma de dicionário, conta com aproximadamente 450 entradas (verbertes) que trazem à luz não apenas conceitos fundamentais, a respeito das Teorias Narrativas contemporâneas, mas também aplicações e metodologias que colocam em relação a narratologia, a mídia e a Comunicação

    Numerical simulation of two-degree-of-freedom vortex induced vibration in a circular cylinder with OpenFOAM

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    Computational fluid dynamics tools are capable to simulate the influence of a fluid flow passing around an object. The ability to predict the impact of such flows on a specific product performance is time consuming and costly without some form of simulation tool. In fact, across a wide range of engineering areas, virtual development allows the reduction of the number of prototypes and less testing until a product is ready to the market. Therefore, it is important to provide computational fluid dynamics users with easy-to-use, robust, time-efficient and validated processes. Bearing this in mind, the current thesis studies the phenomenon of vortex induced vibrations simulating a flow around an oscillatory cylinder. A flow passing around a rhombic body originates dynamic forces which, consequently, induce a set of body movements that are well characterized in the literature. To perform the numerical investigation of this phenomenon was used the OpenFOAM, an opensource software which is numerically able to perform a detailed and accurate analysis of this complex phenomena. Given the few scientific studies about the vortex induced vibration phenomenon with two degrees of freedom, this thesis aims to validate the Open-FOAM software for this case study, providing the scientific community the validation of a new numerical tool for studies of this kind. With this goal, it was firstly performed a mesh independence study for a flow around a fixed cylinder where it was studied the influence of the mesh on the fundamental quantities, that is, the Strouhal number, St, the mean drag coefficient, CD,mean, and the root mean square of the drag, CD,rms, and lift, CL,rms, coefficients. Then, it was carried out the study of the flow around a cylinder with one degree of freedom. It was studied the response of the cylinder for two types of systems, mass-spring system and mass-spring-damper system for a mesh with a 2500D domain length. The obtained results where then compared with the data described in the literature for a 50D length mesh, allowing to infer which is the impact of the mesh size into the obtained results. Finally, it was studied the phenomena generated by a flow around a cylinder with two degrees of freedom. In order to validate this analysis, the obtained results for a 8D mesh were compared with the data described in the literature for a similar numeric study. The main difference obtained between both studies was the symmetry of the geometry of the cylinder’s oscillatory movement which was obtained by the current study whereas the comparative study showed an asymmetric movement of the cylinder. Given this data, it was hypothesised and proven that this fact was associated with the non-symmetry of the mesh used by the literature paper. Subsequently, it was studied the influence of the mesh refinement level in the response given by the cylinder with two degrees of freedom. It was also analysed how the size of the mesh domain influences the response given by the cylinder with two degrees of freedom. Particularly, it was compared the geometry of the oscillatory motion and the temporal evolution of the respective lift coefficient between meshes with 8D, 20D, 500D and 2500D size

    Elucidar o papel dos proteomas estatísticos no cancro em humanos

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    Doutoramento em BiomedicinaDeregulation of various components of the protein synthesis machinery, including tRNAs, aminoacyl-tRNA synthetases and tRNA modifying enzymes, are common in tumors, raising the hypothesis that protein synthesis accuracy is compromised in cancer. To clarify this hypothesis, we determined the relative error rate of protein synthesis and observed that tumors mistranslate at higher levels than normal tissue. To understand the role of mistranslation in tumor biology, we expressed mutant Ser-tRNAs that misincorporate Ser-at-Ala (frequent error) and Ser-at-Leu (infrequent error) sites in NIH3T3 cells. The tRNA that misincorporated Ser-at-Ala codon sites induced tumor growth with similar kinetics of K-rasV12 expressing tumors. Upregulation of the AKT pathway and differential activation of the UPR, depending on the tRNA being expressed, were also observed. However, these studies did not clarify the role of tRNA deregulation or tRNA misreading in tumor initiation or progression. For this, a WT-Ser tRNA and a tRNA that misincorporates Ser-at-Ala codon sites were expressed in cells derived from normal bronchial epithelium (BEAS-2B) and in cells derived from a Large cell lung carcinoma (H460). The BEAS-2B cell lines studies showed that increased cell proliferation in vitro, increased protein synthesis rate and activation of UPR biomarkers, which were dependent on the recombinant tRNA being expressed. Both tRNA constructs increased colony formation capacity in vitro. Interestingly, the data suggest that upregulation of the WT Ser-tRNA is sufficient to trigger tumor formation, albeit with very slow growth kinetics. When the same tRNAs were expressed in H460 cells, tumor growth kinetics and local invasion potential of the cells increased. Finally, upregulation of the WT-Ser tRNA decreases tumor cell sensitivity to cisplatin treatment. The overall study highlights new features of tRNA function in tumor biology and open new avenues to explore the role of protein synthesis in cancer.A desregulação dos componentes da maquinaria de síntese proteica, tais como tRNAs, aminoacil-tRNA sintetases, e enzimas modificadoras dos tRNAs, é comum em tumores, levantando a hipótese de que a fidelidade da síntese proteica pode estar comprometida em tumores. Para clarificar esta hipótese, determinámos a taxa de erro da síntese proteica e observámos que os tumores produzem mais erros na síntese de proteínas que os tecidos normais. De modo a compreender o papel dos erros de tradução na biologia tumoral, expressámos tRNAs de Serina mutantes que incorporam Ser em locais de Ala (erro frequente) e Ser em locais de Leu (erro raro) na linha celular NIH3T3. O tRNA que incorpora Ser em locais de Ala, promoveu o crescimento tumoral com uma cinética semelhante à induzida pela mutação K-rasV12. A activação da via AKT e a activação diferencial da UPR, dependendo do tRNA expresso, também foram observadas. No entanto, a expressão dos tRNAs mutantes nas linha celulares derivadas das NIH3T3 não permitiu clarificar o papel dos tRNAs recombinantes na iniciação ou na progressão tumoral. Para tal, expressámos um tRNA de Serina WT e o tRNA mutante insere Ser em locais de Ala em células derivadas de epitélio bronquial normal, BEAS-2B, e em células derivadas de Carcinoma de células grandes do pulmão, H460. A expressão destes tRNAs na linha celular normal, aumentou a proliferação celular, a taxa de síntese proteica e a activação de biomarcadores da via da UPR, a qual é dependente do tRNA expresso. Ambos os tRNAs favoreceram a formação de colónias in vitro. O aumento da expressão do tRNA de Serina WT foi suficiente para iniciar a formação de tumores de crescimento lento. Quando expressámos os mesmos tRNAs nas células tumorais H460, observámos um aumento na cinética de crescimento tumoral e no potencial de invasão local das células, embora os resultados obtidos não permitam tirar uma conclusão definitiva acerca do envolvimento dos tRNAs na progressão tumoral. O aumento da expressão do tRNA de Serina WT torna células tumorais mais resistentes ao tratamento com cisplatina. De um modo geral, os nossos resultados sugerem que a desregulação de tRNAs e o aumento dos erros da síntese proteica são importantes para a biologia dos tumores

    The absent players : the impact of firms with no trading activity : estudo exploratório

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    O nosso estudo têm por objetivo analisar as diferenças que existem entre os níveis de transação em empresas que se encontram cotadas no mercado de capitais e perceber o motivo pelo qual permanecem cotadas, com recurso a uma nova medida que analisa a percentagem de dias em que não existe qualquer retorno, denominada por Zero-Return Metric. Utilizando uma base de dados de 2.502 empresas para o período entre 2004 a 2014 do principal índice acionista do Reino Unido, é apresentado uma mediana de 58,7% de dias em que não existe qualquer retorno. Partimos do pressuposto que as empresas pretendem aceder a esta estrutura de financiamento devido às vantagens que apresenta, contudo nem todas as empresas conseguem captar de igual forma os seus benefícios. Com base nisto, é possível observar diferenças significativas na visibilidade, nas necessidades de capital, no grau de concentração da estrutura acionista e na liquidez entre as empresas, o que pode explicar algumas diferenças no nível de transação. Como consequência, a taxa de sobrevivência deste tipo de empresas é bastante inferior, sendo um importante indicador do seu grau de desempenho. O nosso objetivo passa por apresentar um estudo compreensivo sobre este efeito, lançando as bases para um estudo mais aprofundado nesta área.Our study aims to analyze the differences between the transactions levels in companies that are listed on the capital market, and realize why they remain listed, using a new measure that analyses the proportion of zero-return days (thereafter referred to as the zero-return metric). Using a Database with 2.502 firms for the period 2004-2014 of the main UK stock market index, a median with 58,7% of days without a return is represented. We assume that the companies want to access this financing structure due to the advantages they offer, however not all companies are able to capture the same way its benefits. On this basis, it is possible to observe significant differences in visibility, capital needs and growth, in the degree of shareholders structure and liquidity, which may explain some differences in transaction level. As a result, the survival rates for those companies is much lower, being an important indicator of their level of performance. Our objective is to present a comprehensive descriptive study of this effect, laying the foundations to a more in depth study

    Geografia e democracia para uma nova justiça

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    À luz da investigação realizada no âmbito do Observatório Permanente da Justiça Portuguesa sobre a reorganização territorial da justiça em Portugal, apresenta-se um novo modelo de geografia da justiça, tendo em vista, em primeira linha, melhorar o desempenho dos tribunais enquanto serviço público de justiça e, sobretudo, como instâncias de promoção e de defesa dos direitos dos cidadãos. Nesse sentido uma proposta de territorialização impõe uma agenda estratégica da justiça em que se reafirme a promoção do princípio do acesso à justiça e ao direito, se aprofunde a qualidade da justiça, se aumente a eficiência, a eficácia e a transparência do sistema judicial bem como a modernização e reforço da capacidade de administração e gestão do sistema

    Cloud characterization in the presence of aerosols over Portugal region

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    Este trabalho investiga a interacção entre aerossóis minerais, do tipo poeiras do deserto, e propriedades de nuvens sobre a Península Ibérica e Oceano Atlântico circundante. Esta interacção é feita utilizando modelação atmosférica regional e dados de detecção remota, fornecidas por satélite e medições in situ. A determinação das propriedades dos aerossóis fornece informações sobre a altitude da camada de aerossóis e a determinação das propriedades das nuvens, influenciadas pela presença de aerossóis, fornece informações sobre as alterações que essas nuvens podem sofrer. O forçamento radiativo, devido a nuvens e a aerossóis, no topo da atmosfera e à superfície, também são estimados. Os resultados deste estudo confirmam que os aerossóis minerais alteram as propriedades das nuvens. Com esta pesquisa é feita uma contribuição para melhor compreender a interacção de nuvens/aerossóis, bem como sua interacção com a radiação. É obtida também uma quantificação dos efeitos radiativos devido a nuvens e/ou aerossóis; ABSTRACT:This work investigates the interaction between mineral desert dust aerosols and cloud properties over the Iberian Peninsula and the Atlantic Ocean surrounding area. This interaction is studied using regional atmospheric modeling and remote sensing data, provided by satellite and in situ measurements. The assessment of the aerosol properties provides information on the aerosol layers altitude and the cloud properties determination, influenced by the desert dust aerosols presence, gives information about the alterations that clouds may suffer. The aerosol and cloud radiative forcing at the top of the atmosphere and at surface levels are also estimated. The results of this study are consistent with mineral aerosols altering cloud properties and changing cloud amounts. With this research a contribution is made in order to better understand the interaction of clouds/aerosols as well as their interaction with radiation. A contribution is also made for the quantification of cloud/aerosol radiative effects

    Direct Selling: The Role of Risk In Consumer’s Acceptance and Satisfaction

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    This paper considers the role of perceived risk in consumer’s satisfaction and acceptance of direct selling. Direct selling has been exhibiting in the last decade substantial growth in sales revenues and number of salespeople involved. Also the acceptance on the part of the consumers has been increasing; in spite of they show more and more demanding and informed. The literature reveals that the relationship between customer satisfaction and direct selling has not been sufficiently studied, yet. This paper, applying a quantitative approach attempts to provide some data on this relation. Results indicate that there is a negative correlation between perceived risk and direct selling acceptance and also a positive correlation between direct selling acceptance and satisfaction
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