Conception d’un mécanisme déployable à grand ratio d’expansion et de son système d’actionnement par roues d’inertie pour applications spatiales

Cette thèse propose de développer des mécanismes déployables pour applications spatiales ainsi que des modes d’actionnement permettant leur déploiement et le contrôle de l’orientation en orbite de l’engin spatial les supportant. L’objectif étant de permettre le déploiement de surfaces larges pour des panneaux solaires, coupoles de télécommunication ou sections de station spatiale, une géométrie plane simple en triangle est retenue afin de pouvoir être assemblée en différents types de surfaces. Les configurations à membrures rigides proposées dans la littérature pour le déploiement de solides symétriques sont optimisées et adaptées à l’expansion d’une géométrie ouverte, telle une coupole. L’optimisation permet d’atteindre un ratio d’expansion plan pour une seule unité de plus de 5, mais présente des instabilités lors de l’actionnement d’un prototype. Le principe de transmission du mouvement d’un étage à l’autre du mécanisme est revu afin de diminuer la sensibilité des performances du mécanisme à la géométrie de ses membrures internes. Le nouveau modèle, basé sur des courroies crantées, permet d’atteindre des ratios d’expansion plans supérieurs à 20 dans certaines configurations. L’effet des principaux facteurs géométriques de conception est étudié afin d’obtenir une relation simple d’optimisation du mécanisme plan pour adapter ce dernier à différents contextes d’applications. La géométrie identique des faces triangulaires de chaque surface déployée permet aussi l’empilement de ces faces pour augmenter la compacité du mécanisme. Une articulation spécialisée est conçue afin de permettre le dépliage des faces puis leur déploiement successivement. Le déploiement de grandes surfaces ne se fait pas sans influencer lourdement l’orientation et potentiellement la trajectoire de l’engin spatial, aussi, différentes stratégies de contrôle de l’orientation novatrices sont proposées. Afin de tirer profit d’une grande surface, l’actionnement par masses ponctuelles en périphérie du mécanisme est présentée, ses équations dynamiques sont dérivées et simulées pour en observer les performances. Celles-ci démontrent le potentiel de cette stratégie de réorientation, sans obstruction de l’espace central du satellite de base, mais les performances restent en deçà de l’effet d’une roue d’inertie de masse équivalente. Une stratégie d’actionnement redondant par roue d’inertie est alors présentée pour différents niveaux de complexité de mécanismes dont toutes les articulations sont passives, c’est-à-dire non actionnées. Un mécanisme à quatre barres plan est simulé en boucle fermée avec un contrôleur simple pour valider le contrôle d’un mécanisme ciseau commun. Ces résultats sont étendus à la dérivation des équations dynamiques d’un mécanisme sphérique à quatre barres, qui démontre le potentiel de l’actionnement par roue d’inertie pour le contrôle de la configuration et de l’orientation spatiale d’un tel mécanisme. Un prototype à deux corps ayant chacun une roue d’inertie et une seule articulation passive les reliant est réalisé et contrôlé grâce à un suivi par caméra des modules. Le banc d’essai est détaillé, ainsi que les défis que l’élimination des forces externes ont représenté dans sa conception. Les résultats montrent que le système est contrôlable en orientation et en configuration. La thèse se termine par une étude de cas pour l’application des principaux systèmes développés dans cette recherche. La collecte de débris orbitaux de petite et moyenne taille est présentée comme un problème n’ayant pas encore eu de solution adéquate et posant un réel danger aux missions spatiales à venir. L’unité déployable triangulaire entraînée par courroies est dupliquée de manière à former une coupole de plusieurs centaines de mètres de diamètre et est proposée comme solution pour capturer et ralentir ces catégories de débris. Les paramètres d’une mission à cette fin sont détaillés, ainsi que le potentiel de réorientation que les roues d’inertie permettent en plus du contrôle de son déploiement. Près de 2000 débris pourraient être retirés en moins d’un an en orbite basse à 819 km d’altitude.

Dancing the Archive: Rhythms of Change in Post-Volcano Identities on Montserrat, West Indies

In this dissertation, I demonstrate how improvisations within the structures of performance during Montserrat’s annual festivals produce “rhythms of change” that contribute to the formation of cultural identities. Montserrat is a small island of 39.5 square miles in the Caribbean’s Leeward Islands, and a volcanic disaster in the 1990s led to the loss of villages, homes, and material possessions. The crisis resulted in mass displacement and emigration, and today’s remaining population of 5,000 is now in a stage of post-volcano redevelopment. The reliability of written archives for establishing cultural knowledge is tenuous, and the community is faced with re-energizing cherished cultural traditions. This ethnographic research traces my embodied search for Montserrat’s history through an archive that is itself intangible and performative. Festivals produce some of the island’s most visible and culturally political events, and music and dance performances prompt on- and off-stage discussions about the island’s multifaceted heritage. The festival cycle provides the structure for ongoing renegotiations of what it means to be “Montserratian.” I focus especially on the island’s often-discussed and debated “triangular” heritage of Irishness, Africanness, and Montserratianness as it is performed during the festivals. Through my meanderings along the winding hilly roads of Montserrat, I explored reconfigurations of cultural memory through the island’s masquerade dance tradition and other festival celebrations. In this work, I introduce a “Cast of Characters,” each of whose scholarly, artistic, and public service work on Montserrat contributes to the shape and transformation of the island’s post-volcano cultural identities today. This dissertation is about the kinesthetic transmission of shared (and sometimes unshared) cultural knowledge, the substance of which echoes in the rhythms of Montserrat’s music and dance practices today.

The impact of gillnet mesh sizes on Oreochromis niloticus: a proposed management strategy

Gillnets are popularly used in commercial fishing on both Lake kioga and lake Victoria. On Lake kioga the legal mesh size is from 4½ (114) upwards while on Lake Victoria, a multifishery lake, various mesh sizes are in operation. However, the fishermen on these lakes still use the smaller meshes to be able to harvest certain categories of fish especially Oreochromis species group whose catch rates are already on the decline due to either use of small mesh size nets, high fishing pressure and to L.Kioga in particular, predation by lates niloticus.

Devaluation, competitiveness and new business formation in emerging countries

In September 2010, Brazil’s Finance Minister, Guido Mantega, used the term “currency war” with reference to monetary policies implemented by different countries to generate an artificial devaluation of their currency and achieve a cheaper, more competitive domestic economy that may be attractive to foreign investors. Similar cases have been documented since the 1930s Great Depression, when several countries abandoned the gold standard as backing for their currencies. More recently, a large-scale asset purchase by Japan’s Central Bank in 2013 was singled out as a strategy aimed at generating devaluation of the yen. This research uses statistics of new business formation density reported by Doing Business for 30 emerging countries in the period 2004-2011 to evaluate the impact of devaluation measured by the behavior of the real effective exchange rate (REER) on the rate of new business formation (NBF). It is determined how variables associated with competitiveness affect the relationship between devaluation and business formation. Results show that devaluation has a positive effect on NBF in the short term, which gets diluted in the long term. Countries with greater competitiveness have less dependence on devaluation to increase the number of businesses.

Truncation identities for the small polaron fusion hierarchy

We study a one-dimensional lattice model of interacting spinless fermions. This model is integrable for both periodic and open boundary conditions; the latter case includes the presence of Grassmann valued non-diagonal boundary fields breaking the bulk U(1) symmetry of the model. Starting from the embedding of this model into a graded Yang-Baxter algebra, an infinite hierarchy of commuting transfer matrices is constructed by means of a fusion procedure. For certain values of the coupling constant related to anisotropies of the underlying vertex model taken at roots of unity, this hierarchy is shown to truncate giving a finite set of functional equations for the spectrum of the transfer matrices. For generic coupling constants, the spectral problem is formulated in terms of a functional (or TQ-)equation which can be solved by Bethe ansatz methods for periodic and diagonal open boundary conditions. Possible approaches for the solution of the model with generic non-diagonal boundary fields are discussed.

O empreendedorismo e a inovação como fatores de sucesso nas pequenas e médias empresas

Mestrado em Gestão e Empreendedorismo

Ritual and routine: a means of adaption

Researchers have demonstrated how engaging in rituals or ‘patterned’ behaviours can help people cope with stressful situations and significant life changes. However, limited knowledge exists on the role of ritual practices in prison and how federally incarcerated Canadian men use these rituals to deal with their imprisonment. To respond to this lacuna in the literature, transcripts from 56 semi-structured interviews with former male federal prisoners released on parole into Ontario, Canada, were analyzed for emergent themes identifying the purpose of ritual and routine practices across prisons with different security classifications. Findings reveal the effectiveness of rituals for managing and mitigating the stresses of incarceration, specifically that prisoners’ routine behaviours constitute a positive strategy of adaption to incarceration (e.g., alleviating stress and passing time) in preparation for life postincarceration (e.g., anticipatory socialization). Structural Ritualization Theory frames the analyses and implications presented in this study.

Reframing Scottish Football: Strategy and the short-term nature of the football industry.

Despite football being deeply entrenched in Scottish culture it is under-researched from a business perspective. This research develops a conceptual framework that views professional football clubs from a number of different perspectives. It draws on strategic management literature since this views the firm as the intersection between internal competence, customer perception and competition within an industry. A review of previous sports business research highlighted five main themes that were used to create a structure for the analysis: on-field performance, attendance, finance, the playing squad and the manager. These themes were used as frames to view the firms within the industry from a number of different perspectives. Each frame allows a different aspect of the firm to be considered singly in turn and then collectively to develop a deeper understanding of the existing frames in use within the industry. The research is based on a pragmatic philosophy that allows mixed methods to be combined to provide both an objective and subjective view of the industry. The subjective view was drawn from five interviews with senior figures within Scottish professional football. These participants were from a number of different roles and organisations within the industry to provide a balance of experiences. The views were triangulated with a descriptive analysis of secondary data from a number of industry sources to establish patterns within and between these frames. A peer group of six clubs was selected as they competed in the Scottish Premier League in each of the seasons within an eleven-year period (2000-2011). The peer group clubs selected were: Aberdeen, Dundee United, Heart of Midlothian (Hearts), Hibernian, Kilmarnock and Motherwell. By focussing on a small group of clubs with a similar on-field record a broad study across the five frames could be carried out in detail without the findings being influenced by the impact of relegation to a lower division or sustained participation in European football. Within each of the original five frames a number of sub-components were identified and linked to the framework; this expanded the content to reflect the findings of this project. There appeared to be little link between on-field performance and attendance although progress to the later stages of cup competitions allowed clubs to connect with fans who do not regularly attend. The relationship between a club’s income and wage bill should be expanded to include interest repayments since this expenditure can be used to highlight future financial problems caused by increased debt levels. Although all of the interview participants spoke with pride of the players that had progressed from the club’s youth academy to success at the highest level the peer group clubs only produced one player each season that played more than ten matches for the club. Almost half of the players signed from the youth academy left the club without playing for the 1st Team. The importance of the relationship between the manager and club chairman was highlighted, although the speed with which managers were appointed suggests that little consideration was given to this before offering a contract. Once appointed there appeared to be little clarity over the job description and areas of responsibility. Several of the interviewees brought experience from other businesses to football but admitted that short-term decision making and entrenched behaviour made change difficult. The conclusion of the research is that by taking a firm-wide view of the club, longer-term decisions can be taken within football. Player development and supporter relationships were both identified as long-term processes that are impacted by the current short-termism. With greater role clarity for managers and a mixture of short and long-term objectives those involved in the industry are more likely to have opportunities to learn from experience and performance, across the different frames, will improve as a result.

La planificación territorial de la política de renovación de las áreas turísticas maduras. Planes de Renovación, Mejora e Incremento de la Competitividad de Canarias

La renovación integral del espacio público y privado de las áreas turísticas maduras se plantea como el elemento de articulación de la política turística. Sin embargo, la experiencia acumulada plantea la necesidad de generar escenarios de buena gobernanza del territorio, en detrimento de la implementación de una estrategia de intervención pública por la vía impositiva de la norma. Para ello, la política pública de las Islas Canarias (España) ha incorporado un singular y novedoso instrumento de ordenación territorial: los “Planes de Modernización, Mejora e Incremento de la Competitividad”. Se trata de planes ad hoc que, con un carácter excepcional, pretenden convertirse en los mecanismos que, vía convenio urbanístico, deben dar cobertura, viabilizar y agilizar la ejecución eficiente de los proyectos de renovación física de los alojamientos turísticos. Sin embargo, la implementación de estos planes no está exenta de complicaciones, las cuales están reduciendo su eficiencia. El principal objetivo de este trabajo es analizar las debilidades y potencialidades de estos instrumentos, susceptibles de ser aplicados a ámbitos turísticos similares.

Defining a management strategy for the azorean natural thermal resources : valuing criteria identification

Dissertação de Mestrado, Gestão de Empresas (MBA), 23 de Maio de 2016, Universidade dos Açores.

Causality in Europeanization Research: A Discursive Institutional Analytical Strategy

Discourse analysis as a methodology is perhaps not readily associated with substantive causality claims. At the same time the study of discourses is very much the study of conceptions of causal relations among a set, or sets, of agents. Within Europeanization research we have seen endeavours to develop discursive institutional analytical frameworks and something that comes close to the formulation of hypothesis on the effects of European Union (EU) policies and institutions on domestic change. Even if these efforts so far do not necessarily amount to substantive theories or claims of causality, it suggests that discourse analysis and the study of causality are by no means opposites. The study of Europeanization discourses may even be seen as an essential step in the move towards claims of causality in Europeanization research. This paper deals with the question of how we may move from the study of discursive causalities towards more substantive claims of causality between EU policy and institutional initiatives and domestic change.

TRIB2 in human AML: a biological and clinical investigation

Acute myeloid leukemia (AML) involves the proliferation, abnormal survival and arrest of cells at a very early stage of myeloid cell differentiation. The biological and clinical heterogeneity of this disease complicates treatment and highlights the significance of understanding the underlying causes of AML, which may constitute potential therapeutic targets, as well as offer prognostic information. Tribbles homolog 2 (Trib2) is a potent murine oncogene capable of inducing transplantable AML with complete penetrance. The pathogenicity of Trib2 is attributed to its ability to induce proteasomal degradation of the full length isoform of the transcription factor CCAAT/enhancer-binding protein alpha (C/EBPα p42). The role of TRIB2 in human AML cells, however, has not been systematically investigated or targeted. Across human cancers, TRIB2 oncogenic activity was found to be associated with its elevated expression. In the context of AML, TRIB2 overexpression was suggested to be associated with the large and heterogeneous subset of cytogenetically normal AML patients. Based upon the observation that overexpression of TRIB2 has a role in cellular transformation, the effect of modulating its expression in human AML was examined in a human AML cell line that expresses high levels of TRIB2, U937 cells. Specific suppression of TRIB2 led to impaired cell growth, as a consequence of both an increase in apoptosis and a decrease in cell proliferation. Consistent with these in vitro results, TRIB2 silencing strongly reduced progression of the U937 in vivo xenografts, accompanied by detection of a lower spleen weight when compared with mice transplanted with TRIB2- expressing control cells. Gene expression analysis suggested that TRIB2 modulates apoptosis and cell-cycle sensitivity by influencing the expression of a subset of genes known to have implications on these phenotypes. Furthermore, TRIB2 was found to be expressed in a significant subset of AML patient samples analysed. To investigate whether increased expression of this gene could be afforded prognostic significance, primary AML cells with dichotomized levels of TRIB2 transcripts were evaluated in terms of their xenoengraftment potential, an assay reported to correlate with disease aggressiveness observed in humans. A small cohort of analysed samples with higher TRIB2 expression did not associate with preferential leukaemic cell engraftment in highly immune-deficient mice, hence, not predicting for an adverse prognosis. However, further experiments including a larger cohort of well characterized AML patients would be needed to clarify TRIB2 significance in the diagnostic setting. Collectively, these data support a functional role for TRIB2 in the maintenance of the oncogenic properties of human AML cells and suggest TRIB2 can be considered a rational therapeutic target. Proteasome inhibition has emerged as an attractive target for the development of novel anti-cancer therapies and results from translational research and clinical trials support the idea that proteasome inhibitors should be considered in the treatment of AML. The present study argued that proteasome inhibition would effectively inhibit the function of TRIB2 by abrogating C/EBPα p42 protein degradation and that it would be an effective pharmacological targeting strategy in TRIB2-positive AMLs. Here, a number of cell models expressing high levels of TRIB2 were successfully targeted by treatment with proteasome inhibitors, as demonstrated by multiple measurements that included increased cytotoxicity, inhibition of clonogenic growth and anti-AML activity in vivo. Mechanistically, it was shown that block of the TRIB2 degradative function led to an increase of C/EBPα p42 and that response was specific to the TRIB2-C/EBPα axis. Specificity was addressed by a panel of experiments showing that U937 cells (express detectable levels of endogenous TRIB2 and C/EBPα) treated with the proteasome inhibitor bortezomib (Brtz) displayed a higher cytotoxic response upon TRIB2 overexpression and that ectopic expression of C/EBPα rescued cell death. Additionally, in C/EBPα-negative leukaemia cells, K562 and Kasumi 1, Brtz-induced toxicity was not increased following TRIB2 overexpression supporting the specificity of the compound on the TRIB2-C/EBPα axis. Together these findings provide pre-clinical evidence that TRIB2- expressing AML cells can be pharmacologically targeted with proteasome inhibition due, in part, to blockage of the TRIB2 proteolytic function on C/EBPα p42. A large body of evidence indicates that AML arises through the stepwise acquisition of genetic and epigenetic changes. Mass spectrometry data has identified an interaction between TRIB2 and the epigenetic regulator Protein Arginine Methyltransferase 5 (PRMT5). Following assessment of TRIB2‟s role in AML cell survival and effective targeting of the TRIB2-C/EBPα degradation pathway, a putative TRIB2/PRMT5 cooperation was investigated in order to gain a deeper understanding of the molecular network in which TRIB2 acts as a potent myeloid oncogene. First, a microarray data set was interrogated for PRMT5 expression levels and the primary enzyme responsible for symmetric dimethylation was found to be transcribed at significantly higher levels in AML patients when compared to healthy controls. Next, depletion of PRMT5 in the U937 cell line was shown to reduce the transformative phenotype in the high expressing TRIB2 AML cells, which suggests that PRMT5 and TRIB2 may cooperate to maintain the leukaemogenic potential. Importantly, PRMT5 was identified as a TRIB2-interacting protein by means of a protein tagging approach to purify TRIB2 complexes from 293T cells. These findings trigger further research aimed at understanding the underlying mechanism and the functional significance of this interplay. In summary, the present study provides experimental evidence that TRIB2 has an important oncogenic role in human AML maintenance and, importantly in such a molecularly heterogeneous disease, provides the rational basis to consider proteasome inhibition as an effective targeting strategy for AML patients with high TRIB2 expression. Finally, the identification of PRMT5 as a TRIB2-interacting protein opens a new level of regulation to consider in AML. This work may contribute to our further understanding and therapeutic strategies in acute leukaemias.

Education in occupational health psychology: Where have we been, where are we now and where are we going?

At the first full conference of the European Academy of Occupational Health Psychology (Lund, 1999), the decision was ratified to organise activities around three fora. These together represented the pillars on which the European Academy had been founded that same year: education, research and professional practice. Each forum was convened by a chair person and a small group of full members; it was agreed that a forum meeting would take place at each full conference and working groups would be established to move developments forward between conferences. The forum system has proven an effective means by which to channel the energies of individual members, and the institutions that they represent, towards advancements in all three areas of activity in occupational health psychology (OHP) in Europe. During the meeting of the education forum at the third full European Academy conference (Barcelona, 2001), the proposal was made for the establishment of a working party that would be tasked with the production of a strategy document on The Promotion of Education in Occupational Health Psychology in Europe. The proposal was ratified at the subsequent annual business meeting held during the same conference. The draft outline of the strategy document was published for consultation in the European Academy’s e-newsletter (Vol. 3.1, 2002) and the final document presented to the meeting of the education forum at the fourth full conference (Vienna, 2002). The strategy document constituted a seminal piece of literature in so far as it provided a foundation and structure capable of guiding pan-European developments in education in OHP – developments that would ensure the sustained growth of the discipline and assure it of a long-standing embedded place in both the scholarly and professional domains. To these ends, the strategy document presented six objectives as important for the sustained expansion and the promotion of education in the discipline in Europe. Namely, the development of: [1] A core syllabus for education in occupational health psychology [2] A mechanism for identifying, recognising and listing undergraduate and postgraduate modules and courses (programmes) in occupational health psychology [3] Structures to support the extension of the current provision of education in occupational health psychology [4] Ways of enhancing convergence of the current provision of education in occupational health psychology [5] Ways of encouraging regional cooperation between education providers across the regions of Europe [6] Ways of ensuring consistency with North American developments in education and promoting world wide co-operation in education Five years has elapsed since the presentation of these laudable objectives to the meeting of the education forum in Vienna in December 2002. In that time OHP has undergone considerable growth, particularly in Europe and North America. Expansion has been reflected in the evolution of existing, and emergence of new, representative bodies for the discipline on both sides of the Atlantic Ocean. As such, it might be considered timely to pause to reflect on what has been achieved in respect of each of the objectives set out in the strategy document. The current chapter examines progress on the six objectives and considers what remains to be done. This exercise is entered into not merely in order to congratulate achievements in some areas and lament slow progress in others. Rather, on the one hand it serves to highlight areas where real progress has been made with a view to the presentation of these areas as ripe for further capitalisation. On the other hand it serves to direct the attention of stakeholders (all those with a vested interest in OHP) to those key parts of the jigsaw puzzle that is the development of a self-sustaining pan-European education framework which remain to be satisfactorily addressed.

A Fuzzy Decision Strategy for Topic Identification and Dynamic Selection of Language Models

International audience

Análise experimental do efeito da diversificação em carteiras de ações: a relação entre risco e quantidade de ativos sob a ótica da estratégia ingênua

The objective is to analyze the relationship between risk and number of stocks of a portfolio for an individual investor when stocks are chosen by "naive strategy". For this, we carried out an experiment in which individuals select actions to reproduce this relationship. 126 participants were informed that the risk of first choice would be an asset average of all standard deviations of the portfolios consist of a single asset, and the same procedure should be used for portfolios composed of two, three and so on, up to 30 actions . They selected the assets they want in their portfolios without the support of a financial analysis. For comparison we also tested a hypothetical simulation of 126 investors who selected shares the same universe, through a random number generator. Thus, each real participant is compensated for random hypothetical investor facing the same opportunity. Patterns were observed in the portfolios of individual participants, characterizing the curves for the components of the samples. Because these groupings are somewhat arbitrary, it was used a more objective measure of behavior: a simple linear regression for each participant, in order to predict the variance of the portfolio depending on the number of assets. In addition, we conducted a pooled regression on all observations by analyzing cross-section. The result of pattern occurs on average but not for most individuals, many of which effectively "de-diversify" when adding seemingly random bonds. Furthermore, the results are slightly worse using a random number generator. This finding challenges the belief that only a small number of titles is necessary for diversification and shows that there is only applicable to a large sample. The implications are important since many individual investors holding few stocks in their portfolios