206 research outputs found
Grasping cybersecurity: A set of essential mental models
No full textFor most people, cybersecurity is a hard to grasp notion. Traditionally, cybersecurity has been considered as a technical challenge and still many specialists view it equivalent with information security, with the notions of confidentiality, integrity and availability as starting points of thinking. And although others searched for a broader perspective, the complexity and ambiguity of the notion still thwarts a common understanding. While developing and executing a MSc cybersecurity program for professionals, the lack of a common understanding of what cybersecurity entails was again observed. Stimulated by this, we started to look for and define a new, transdisciplinary conceptualization of cybersecurity that everyone can agree upon. It resulted in two scientific papers published. This paper describes the outcomes of the continuation of our research journey. It turned out that the earlier introduced description of two key notions, namely that of cyberspace and that of cybersecurity, can still be considered as adequate starting points. Here, we describe a set of additional mental models that elaborates them and provides more detail to the meaning of the two key notions. In practice, it turned out that the additional mental models strongly support the description and analysis of existing and upcoming cybersecurity challenges and helps to understand how everybody, in his or her various roles, can or should contribute to reducing the related cyber risks to adequate levels. We further discovered that for certain cybersecurity challenges, especially those related to efficient cyber risk mitigation, we could not yet identify an adequate sub-set of mental models. This defines the agenda for near future cybersecurity research.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Information and Communication Technolog
[en] IS ENGLISH AN ACCESSORY? INTERDISCIPLINARY PREJUDICE IN A PUBLIC SECTOR SCHOOL IN RIO DE JANEIRO
No full textGut microbiota activate Toll-like receptor 4 to trigger vascularization and BMP2 signalling in the murine small intestine
No full textIn den vergangenen Jahren wurde erforscht, wie die Darmflora auf die Physiologie des Wirtes wirkt. Mikroorganismen fördern die Erneuerung der Dünndarmmukosa und fördern die Ausprägung vaskulärer Netzwerke in den Villusstrukturen des Dünndarms. Trotz der enormen Fortschritte in der Erforschung der Interaktionen zwischen Darmflora und Wirt sind die durch die Darmflora induzierten Signalwege noch weitgehend unerforscht.
Durch den Einsatz keimfreier Maustechnologie erkundet diese Arbeit neue Signalwege. Die Expression der Adaptormoleküle MyD88, TRIF und TOLLIP des angeborenen Immunsystems wurden durch die Darmflora beeinflusst. Diese Adaptormoleküle sind wichtige Determinanten der Toll-like Rezeptor (TLR) mRNA Expression im Dünndarm. TLR5 Transkripte wurden nicht durch die Darmflora beeinflusst und TLR5 war für die Expression anderer TLR Rezeptoren nicht essentiell. TLR5 hatte jedoch eine entscheidende Rolle bei der Induktion der Bone Morphogenetischen Proteine 4 und 7 im Dünndarm.
Die kommensale Darmflora induziert die verstärkte Vaskularisierung der Dünndarmmukosa und verstärkt die Expression von BMP2. Mit einer Tlr4-defizienten Mauslinie konnte gezeigt werden, dass dieser Rezeptor besonders wichtig für die Vaskularisierung der Dünndarmmukosa ist. Die Hemmung von BMP Typ I Rezeptoren in vitro und in vivo zeigte jedoch keine veränderte Angiogenese, was auf andere Funktionen dieser Rezeptoren im Dünndarm hindeutet. Komponenten des Hedgehog Signalwegs waren im keimfreien Mausmodell vermindert exprimiert und die Regulation dieses Signalwegs wurde über TLR4 und TLR5 vermittelt. In vitro Versuche unterstützen eine wichtige aktivatorische Rolle des Hedgehog-Signalwegs bei der Angiogenese intestinaler Endothelzellen.Over the last years there is increasing evidence of the profound impact of gut microbiota in host physiology. Microbes promote renewal of the small intestinal mucosa and increase vascular networks in small intestinal villi. Despite rapid advances in exploring gut microbiota and host interactions, microbiota-induced signalling pathways remain elusive. By taking advantage of germ-free technology, this work reveals novel signalling pathways. Immune adaptors MyD88, TRIF and TOLLIP were affected by gut microbiota and are determinants of Toll-like receptor (TLR) mRNA expression in the small intestine. TLR5 transcripts were not changed by microbiota nor participated in TLR crosstalk but induced the expression of small intestinal Bone Morphogenetic Proteins BMP4 and BMP7, suggesting a novel pathway. Gut microbiota induces vascularization of the gut mucosa and upregulates small intestinal BMP2 levels. TLR4 was shown to be a pivotal pattern recognition receptor supporting mucosal angiogenesis in the small intestine. Inhibition of BMP type I receptors in in vitro and in vivo experiments did not show implications in angiogenesis, suggesting these receptors have other roles in the small intestine. Also, Hedgehog (Hh) signalling was found to be upregulated by gut microbiota and this seemed mediated by TLR4 and TLR5 immune signalling. In vitro experiments appoint for a crucial role of the Hh pathway in promoting angiogenesis of intestinal endothelial cells
Desenvolvimento de uma Ferramenta de Estratégia de Promoções no Segmento de Fast Fashion
No full textFragility functions for tall URM buildings around early 20th century in Lisbon. Part 2: Application to different classes of buildings
No full textThis article describes the application of the procedure for the derivation of fragility functions presented in the companion article entitled Fragility functions for tall URM buildings around early 20th century in Lisbon. Part 1: methodology and application at building level. The procedure, based on the execution of non-linear analyses, was developed to be applied to unreinforced masonry buildings considering both the in-plane and out-of-plane response. Different sources of uncertainty, both epistemic and aleatory, affecting the behaviour of these unreinforced masonry buildings are discussed and treated with a probabilistic procedure. The fragility curves determined for the different classes of buildings are compared and then combined to define the final fragility curves for these unreinforced masonry buildings. The results put in evidence the high seismic vulnerability of these buildings and the urgent need for the structural intervention and for the design of retrofitting measures in order to reduce potential losses due to future earthquakes.The first author would like to acknowledge the financial support of Fundacao para a Ciencia e a Tecnologia (FCT, Ministerio da Educacao e Ciencia, Portugal) through the scholarship PD/BD/106076/2015 through the FCT Doctoral Program: Analysis and Mitigation of Risks in Infrastructures, INFRARISK (http://infrarisk.tecnico.ulisboa.pt)
Seismic assessment of nineteenth and twentieth centuries URM buildings in Lisbon: structural features and derivation of fragility curves
No full textThe article addresses the seismic vulnerability assessment of a typology of unreinforced masonry buildings constructed in Lisbon between the nineteenth and the twentieth centuries. The main architectural and structural features of these buildings are presented. This supported the identification of the main uncertainties affecting their seismic performance and the definition of classes of buildings representative of the typology. The seismic assessment includes the generation of fragility curves that combine the in-plane and out-of-plane response following different criteria and methods of analyses. The results put in evidence the seismic vulnerability of this class of buildings. Considering the earthquake-resistant code for Lisbon with a return period of 475 years, about 50% probability of having heavy damage and about 30% probability of collapse were estimated. The structural intervention on these buildings is urgent in order to reduce losses due to future earthquakes. Further studies for the assessment of similar buildings in Lisbon and elsewhere can be developed using the adopted procedure.The first author would like to acknowledge the financial support of Fundacao para a Ciencia e a Tecnologia (FCT, Ministerio da Educacao e Ciencia, Portugal) through the scholarship PD/BD/106076/2015 through the FCT Doctoral Program: Analysis and Mitigation of Risks in Infrastructures, INFRARISK-(http://infrarisk.tecnico.ulisboa.pt).The authors would also like to acknowledge the contribution from Bruno Silva (Instituto Superior Tecnico) and Nuno Mendes (University of Minho) regarding the ambient vibration tests
Mitochondria, oxidative stress and nonalcoholic fatty liver disease: A complex relationship
No full textAccording to the 'multiple-hit' hypothesis, several factors can act simultaneously in nonalcoholic fatty liver disease (NAFLD) progression. Increased nitro-oxidative (nitroso-oxidative) stress may be considered one of the main contributors involved in the development and risk of NAFLD progression to nonalcoholic steatohepatitis (NASH) characterized by inflammation and fibrosis. Moreover, it has been repeatedly postulated that mitochondrial abnormalities are closely related to the development and progression of liver steatosis and NAFLD pathogenesis. However, it is difficult to determine with certainty whether mitochondrial dysfunction or oxidative stress are primary events or a simple consequence of NAFLD development. On the one hand, increasing lipid accumulation in hepatocytes could cause a wide range of effects from mild to severe mitochondrial damage with a negative impact on cell fate. This can start the cascade of events, including an increase of cellular reactive nitrogen species (RNS) and reactive oxygen species (ROS) production that promotes disease progression from simple steatosis to more severe NAFLD stages. On the other hand, progressing mitochondrial bioenergetic catastrophe and oxidative stress manifestation could be considered accompanying events in the vast spectrum of abnormalities observed during the transition from NAFL to NASH and cirrhosis. This review updates our current understanding of NAFLD pathogenesis and clarifies whether mitochondrial dysfunction and ROS/RNS are culprits or bystanders of NAFLD progression
Defects prediction in the deep drawing of cylindrical components
No full textDissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e TecnologiaO fabrico de recipientes metálicos (latas) para a distribuição de bebida é realizado com recurso a processos de conformação. O alumínio é um dos materiais mais utilizados no fabrico de latas devido às suas características de resistência à oxidação e, em particular, devido às vantagens associada à sua reciclagem. A análise com o auxílio do método dos elementos finitos é, hoje em dia, uma parte integrante no design e conceção do processo de fabrico deste tipo de latas, uma vez que permite a previsão de possíveis defeitos com custos muito menores do que envolvidos na análise experimental. No entanto, a ocorrência de defeitos associados à localização da deformação está intrinsecamente ligada às propriedades mecânicas do material, pelo que a sua previsão depende da capacidade que o modelo constitutivo adotado apresenta na sua descrição.O presente trabalho tem como objetivo principal estudar a influência dos parâmetros do critério de plasticidade na previsão de defeitos, nomeadamente na formação de orelhas de estampagem e na localização da deformação. Neste contexto, foram selecionados dois casos de estudo que envolvem a produção de componentes cilíndricos. O primeiro caso corresponde ao Benchmark 3 – "Previsão de defeitos após estampagem, estampagem inversa e expansão de uma taça", proposto no âmbito da conferência internacional NUMISHEET 2020. O segundo caso, considera apenas o processo de estampagem, mas permite a comparação com resultados experimentais.O material utilizado foi, para ambos os casos de estudo, a liga de alumínio AA3104. No entanto, como foram utilizadas chapas de espessura diferentes foi necessário proceder a identificações distintas dos parâmetros do modelo constitutivo. Em ambos os casos, o encruamento isotrópico foi descrito pela lei de Swift e o comportamento ortotrópico pelo critério de plasticidade comummente designado por CPB06ex2. Todas as identificações foram realizadas com o programa académico DD3MAT e as simulações numéricas com o programa académico DD3IMP.A análise de resultados considerou a evolução da força das várias ferramentas, bem como a distribuição de espessura da taça e o perfil de alturas. Para ambos os casos de estudo, foram analisadas as trajetórias de deformação e evolução das componentes do tensor das tensões, no sistema de eixos material, para vários pontos localizados na zona da chapa inicialmente em contacto com o cerra-chapas. A análise dos estados de tensão para a fase de estampagem permite concluir que estes apresentam uma gama de triaxialidade entre -1/3 e valores cada vez mais próximos de zero, com o parâmetro de Lode a variar de -1 a valores próximos de zero. Os resultados obtidos foram muito semelhantes para os dois casos de estudo, tendo sido possível concluir que isto se deveria a uma semelhança da razão de tamanhos das matrizes e das chapas dos dois casos.O presente trabalho permitiu confirmar a influência da tendência dos coeficientes de Lankford no número de orelhas de estampagem, bem como o impacto da amplitude de variação no plano das tensões à tração na magnitude das orelhas. Para além disso, permitiu realçar a influência da distribuição da tensão de corte na altura média da taça. A forte interação entre todos estes fatores, torna difícil prever o impacto dos parâmetros utilizados nas identificações dos critérios de plasticidade na previsão das orelhas.The manufacture of metal containers (cans) is carried out through forming processes. Aluminum is one of the most used materials for can manufacturing due to its oxidation resistance and, in particular, due to the advantages associated with its recycling. Nowadays, the finite element analysis is an integral part in the design and conception of the manufacturing processes involved in producing this type of cans, since it allows for the prediction of possible defects, with much lesser costs than those involved in the experimental try-out. However, the occurrence of defects associated with strain localization is intrinsically linked to the material's mechanical properties, so its prediction depends on the ability that the adopted constitutive model presents in its description.The main objective of the present work is to study the influence of the yield criteria parameters on the prediction of defects, namely the occurrence of earing after deep drawing and the strain localization. In this context, two case studies that involve the production of cylindrical components were selected. The first case corresponds to Benchmark 3 - "Failure prediction after cup drawing, reverse redrawing and expansion", proposed under the international conference NUMISHEET 2020. The second case considers only the deep drawing process but allows for the comparison with experimental results.The material used was the AA3104 aluminum alloy, for both cases. However, since blanks with different thicknesses were used, it was necessary to proceed to different identifications of the constitutive model' parameters. In both cases, the isotropic hardening was described by the Swift law and the orthotropic behavior by the yield criterion commonly designated as CPB06ex2. All identifications were performed with DD3MAT in-house code and all numerical simulations with DD3IMP in-house code.The result analysis considers the evolution of the force of the various tools, as well as the thickness distribution and height profile of the cup. For both case studies, the following variables were analyzed: strains paths and evolution of the stress tensor components, in the material axis system, for several points located in the blank zone initially in contact with the blank-holder. The analysis of the stress states for the drawing phase allowed concluding that these present a stress triaxiality range between -1/3 and values progressively closer to zero and that the Lode parameter varies from -1 to values close to zero. The results obtained were very similar for both case studies, due to a likeness in the size ratio between the matrixes and blanks of both cases.The present work allowed confirming the influence of the Lankford coefficient tendency in the number of drawing ears, as well as the impact of the in-plane amplitude of variation of the uniaxial yield stresses in the ear magnitude. Furthermore, it highlighted the influence of the shear stress distribution in the average height of the cup. The strong interaction between all of these factors makes it difficult to predict the impact of the parameters used in the identification of the yield criteria in the earing prediction
VOICES FROM THE SOUTH: DECOLONIAL AND POSTCOLONIAL CONVERSATIONS
No full textOver the last ten years, although a certain amount of critical effort has gone into bringing the debates around Postcolonial and Decolonial Studies closer together, these two areas still remain on opposite or different sides of a debate that is often heated and irreconcilable. Particularly at the beginning of the current century, following the publication of Walter Mignolo's (2000) Local Histories/Global Designs, much of the postcolonial criticism found itself on a collision course with decolonial discourse. In the same way, the main authors of the Modernity/Coloniality/Decoloniality group became critics of Postcolonial Studies by formulating the bases of Decolonial thought under the concept of the "Decolonial Turn", which demands a disconnection and break with the Western structures of thought, under which Postcolonialism built its responses to the literature of the former colonialist empires. In this sense, this text intends to investigate the theoretical path that culminates in the break between Decolonial and Postcolonial studies, and our aim is to open up questions that can favor dialogue between the two theoretical fields and also open up possibilities for a South-South dialogue based on a new understanding of the new and old epistemologies
Casas, fantasmas e margens : silêncio e memória traumática em Toni Morrison, Arnaldo Santos e Cornélio Penna
No full textThis work proposes a comparative reading of Toni Morrison s Beloved, Cornélio Penna s A menina morta, and Arnaldo Santo s A casa velha das margens, vis-a-vis the presentification of traumatic memory in the haunted houses represented in the these works. Through a reading of Kafka s short story The Burrow , we have sought to study space as both motivation and strategem for rescuing traumatic memory in the three novels under study. In this sense, the presence of the ghost is perceived not only as a structural element in the narratives being investigated, but as a character representing subalternity. The silence which pervades these fictional works has also been analysed both as a representation of the (im)possibility of speaking and as a form of representing the subaltern within the haunted houses from the perspective of the different ways in which, in its randomness, it deconstructs space, constructing, through language, Beloved, A menina morta and A casa velha das margens as representations of precarious and problematic identitiesCoordenação de Aperfeiçoamento de Pessoal de Nível SuperiorEste trabalho propõe uma leitura comparativa de Beloved, de Toni Morrison, A menina morta, de Cornélio Penna e A casa velha das margens, de Arnaldo Santos, tendo em vista a questão da presentificação da memória traumática no interior de casas assombradas. A partir de A construção, de Kafka, procurou-se estudar o espaço como motivador e artifício dos resgates de memória que se dão nas três obras citadas. Nesse sentido, foi investigada a presença do fantasma enquanto elemento estruturante da narrativa e enquanto personagem dos três romances, em uma perspectiva de subalternidade. Explorou-se, ainda, o silêncio enquanto (im)possibilidade de fala e de representação do subalterno dentro desses locais, e a forma como ele desconstrói em sua errância o espaço das casas, das construções, fazendo de Beloved, A casa velha das margens e A menina morta, enquanto linguagem, representações de identidade precárias e problemáticas
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