856 resultados para Exclusion process, Multi-species, Multi-scale modelling
Oceanic Near-inertial internal waves generation, propagation and interaction with mesoscale dynamics
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Oceans play a key role in the climate system, being the largest heat sinks on Earth. Part of the energy balance of ocean circulation is driven by the Near-inertial internal waves (NIWs). Strong NIWs are observed during a multi-platform, multi-disciplinary and multi-scale campaign led by the NATO-STO CMRE in autumn 2017 in the Ligurian Sea (northwestern Mediterranean Sea). The objectives of this work are as follows: characterise the studied area at different scales; study the NIWs generation and their propagation; estimate the NIWs properties; study the interaction between NIWs and mesoscale structures. This work provides, to the author’s knowledge, the first characterization of NIWs in the Mediterranean Sea. The near-surface NIWs observed at the fixed moorings are locally generated by wind bursts while the deeper waves originate in other regions and arrive at the moorings several days later. Most of the observed NIWs energy propagates downward with a mean vertical group velocity of (2.2±0.3) ⋅10-4 m s-1. On average, the NIWs have an amplitude of 0.13 m s-1 and mean horizontal and vertical wavelengths of 43±25 km and 125±35 m, while shorter wavelengths are observed at the near-coastal mooring, 36±2 km and 33±2 m, respectively. Most of the observed NIWs are blue shifted and reach a value 9% higher than the local inertial frequency. Only two observed NIWs are characterised by a redshift (up to 3% lower than the local inertial frequency). In support of the in situ observations, a high resolution numerical model is implemented using NEMO (Madec et al., 2019). Results show that anticyclones (cyclones) shift the frequency of NIWs to lower (higher) frequencies with respect to the local inertial frequency. Anticyclones facilitate the downward propagation of NIW energy, while cyclones dampen it. Absence of NIWs energy within an anticyclone is also investigated.
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We study the competition interface between two growing clusters in a growth model associated to last-passage percolation. When the initial unoccupied set is approximately a cone, we show that this interface has an asymptotic direction with probability 1. The behavior of this direction depends on the angle theta of the cone: for theta >= 180 degrees, the direction is deterministic, while for theta < 180 degrees, it is random, and its distribution can be given explicitly in certain cases. We also obtain partial results on the fluctuations of the interface around its asymptotic direction. The evolution of the competition interface in the growth model can be mapped onto the path of a second-class particle in the totally asymmetric simple exclusion process; from the existence of the limiting direction for the interface, we obtain a new and rather natural proof of the strong law of large numbers (with perhaps a random limit) for the position of the second-class particle at large times.
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At the core of the analysis task in the development process is information systems requirements modelling, Modelling of requirements has been occurring for many years and the techniques used have progressed from flowcharting through data flow diagrams and entity-relationship diagrams to object-oriented schemas today. Unfortunately, researchers have been able to give little theoretical guidance only to practitioners on which techniques to use and when. In an attempt to address this situation, Wand and Weber have developed a series of models based on the ontological theory of Mario Bunge-the Bunge-Wand-Weber (BWW) models. Two particular criticisms of the models have persisted however-the understandability of the constructs in the BWW models and the difficulty in applying the models to a modelling technique. This paper addresses these issues by presenting a meta model of the BWW constructs using a meta language that is familiar to many IS professionals, more specific than plain English text, but easier to understand than the set-theoretic language of the original BWW models. Such a meta model also facilitates the application of the BWW theory to other modelling techniques that have similar meta models defined. Moreover, this approach supports the identification of patterns of constructs that might be common across meta models for modelling techniques. Such findings are useful in extending and refining the BWW theory. (C) 2002 Elsevier Science Ltd. All rights reserved.
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Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica
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O bacalhau (Gadus morhua) faz parte da dieta alimentar dos portugueses há vários séculos, sendo atualmente, um dos maiores consumidores deste peixe a nível mundial. Após o processo de salga, esta espécie possui características únicas como a consistência, cheiro, paladar e cor amarela. É precisamente devido à coloração do peixe que alguns produtores da Islândia, Noruega e Dinamarca requisitaram às autoridades da União Europeia (UE) a aprovação da utilização de polifosfatos no processo de salga húmida do bacalhau. Os polifosfatos são aditivos alimentares bastante usados no processamento do pescado pois previnem a oxidação dos lípidos e proteínas do músculo do bacalhau, evitando assim a indesejada mudança de cor do peixe. Apesar dos esforços da Associação dos Industriais do Bacalhau (AIB) e do governo português para a rejeição da proposta nórdica, tal não se verificou. Deste modo, no início do próximo ano já será possível a venda na UE de bacalhau com fosfatos. A quantificação do teor de fosfatos no bacalhau é geralmente efetuada por Espetrofotometria de absorção molecular no ultravioleta-visível (UV-Visível). Esta quantificação é baseada no método de determinação do fósforo total, através da hidrólise dos fosfatos a ortofosfatos com posterior medição da cor amarela, gerada pela reação destes com uma solução de molibdato-vanadato. O objetivo desta dissertação foi a validação de um método de análise para a quantificação dos polifosfatos no bacalhau. O método validado foi o descrito na norma NP 4495 para produtos de pesca e aquicultura. O desenvolvimento deste trabalho foi realizado em laboratório acreditado para águas e produtos alimentares (Equilibrium - Laboratório de Controlo de Qualidade e de Processos Lda, L0312). Foi ainda determinada a influência do teor de cloreto de sódio na quantificação dos polifosfatos e o teor de humidade, uma vez que este pode afetar o produto durante a sua comercialização. No processo de validação do método foram estudados diversos parâmetros, tais como a seletividade, linearidade, sensibilidade, limite de quantificação e precisão. Pela análise dos resultados obtidos conclui-se que o método para determinação de fosfatos no bacalhau se encontra validado, uma vez que satisfaz todas as especificações determinadas para cada parâmetro de validação avaliado.
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Dissertação de mestrado em Sociologia (área de especialização em Desenvolvimento e Políticas Sociais)
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Report for the scientific sojourn carried out at the Model-based Systems and Qualitative Reasoning Group (Technical University of Munich), from September until December 2005. Constructed wetlands (CWs), or modified natural wetlands, are used all over the world as wastewater treatment systems for small communities because they can provide high treatment efficiency with low energy consumption and low construction, operation and maintenance costs. Their treatment process is very complex because it includes physical, chemical and biological mechanisms like microorganism oxidation, microorganism reduction, filtration, sedimentation and chemical precipitation. Besides, these processes can be influenced by different factors. In order to guarantee the performance of CWs, an operation and maintenance program must be defined for each Wastewater Treatment Plant (WWTP). The main objective of this project is to provide a computer support to the definition of the most appropriate operation and maintenance protocols to guarantee the correct performance of CWs. To reach them, the definition of models which represent the knowledge about CW has been proposed: components involved in the sanitation process, relation among these units and processes to remove pollutants. Horizontal Subsurface Flow CWs are chosen as a case study and the filtration process is selected as first modelling-process application. However, the goal is to represent the process knowledge in such a way that it can be reused for other types of WWTP.
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A review of extinction risk analysis and viability methods is presented. The importance of environmental, demographic and genetic uncertainties, as well as the role of catastrophes are successively considered, and different approaches aiming at the integration of these risk factors in predictive population dynamic models are discussed.
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A population of Biomphalaria occidentalis was found for the first time in the State of Minas Gerais. It was probavly introduced into the Várzea das Flores dam, in the municipality of Contagem, the area o0f study, during fish stocking in 1985. There is possibility of "competitive exclusion"between that species and B. glabrata, previously the only Biomphalaria found in the region. The present geographical distribution of B. occidentalis in Brazil is listed.
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Climate change poses a serious threat to species persistence. Effective modelling of evolutionary responses to rapid climate change is therefore essential. In this review we examine recent advances in phylogenetic comparative methods, techniques normally used to study adaptation over long periods, which allow them to be applied to the study of adaptation over shorter time scales. This increased applicability is largely due to the emergence of more flexible models of character evolution and the parallel development of molecular technologies that can be used to assess adaptive variation at loci scattered across the genome. The merging of phylogenetic and population genetic approaches to the study of adaptation has significant potential to advance our understanding of rapid responses to environmental change.
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Over the last few decades, the Swiss higher education system has faced important reforms - both concerning its structure and its governance. As with other European countries, one of the most important changes consists of the strengthening of the higher education institutions' research mission through the reinforcement of the role of the National Science Foundation (NSF), which has become increasingly involved in sustaining academic careers. Meanwhile, traditionally and historically, the definition of a faculty member and his or her financial support has come from the higher education institutions (HEI) themselves. This redefinition of power relationships around the funding of academic temporary positions and research activities by the NSF can be analyzed as an attempt to reform the structure of academic careers and the allocation modes of academic positions. Being able to analyze the issue of allocating academic positions within the normative structure of science (Merton, The sociology of science. University of Chicago Press, Chicago, 1973) is a constant concern for those involved in Higher Education Studies. This chapter is an attempt to nurture the debate by questioning, though a quantitative and qualitative research, the tension between the uses of universalist and particularist criteria in the allocation of academic positions. It analyses the possible exclusion process as a consequence of the organization of academic markets and their embeddedness in a wider societal organization.
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Ohjelmistoprosesseissa kulkee käytännössä sama tieto muuntuen eri vaiheissa käyttökohteensa mukaan. Tätä mallinnusinformaatiota on mahdollista siirtää ja käyttää uudelleen, mikä säästää resursseja ja vähentää riskejä kaikissa projektin vaiheissa. Projektin alussa ohjelmiston toimintoja suunnitellaan ja niitä mallinnetaan esim. UML-malleilla. Tätä mallinnusinformaatiota hallitaan erilaisilla CASE-työkaluilla, joiden avullamalleja on helppo konvertoida toteutusvaihetta varten lähdekoodiksi. Lähdekoodivoidaan tuoda takaisin malliksi jatkosuunnittelua varten, jos työkalu tukee ominaisuutta. Testausvaiheessa lähdekoodi voidaan parsia, jotta siitä saadaan esille olennainen mallinnusinformaatio testejä varten. Lopulta dokumentaatiota voidaan generoida automaattisesti esim. Javadocilla. Mallinnusinformaation hyödyntäminen onnistuu hyvin teoriassa, mutta se ei ole niin suoraviivaista käytännössä. Tämänhetkiset työkalut eivät ole tarpeeksi joustavia mallinnusinformaation palauttamiseksi edellisiin vaiheisiin, joten ne ajavat toteuttamaan projekteja lineaarisesti. Keskikokoisessakin ohjelmistoprojektissa on suuri määrä mallinnusinformaatiota ja se lisää haasteita. Vaikka työkalut ovat kankeita, mallinnusinformaation hyödyntämisen on koettu tehostavan ohjelmistoprosesseja. Siksi sen keinoja tutkitaan ahkerasti.
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In vertebrates, signaling by retinoic acid (RA) is known to play an important role in embryonic development, as well as organ homeostasis in the adult. In organisms such as adult axolotls and newts, RA is also important for regeneration of the CNS, limb, tail, and many other organ systems. RA mediates many of its effects in development and regeneration through nuclear receptors, known as retinoic acid receptors (RARs) and retinoid X receptors (RXRs). This study provides evidence for an important role of the RA receptor, RAR~2, in ,( '. regeneration ofthe spinal cord and tail of the adult newt. It has previously been proposed that the ability of the nervous system to regenerate might depend on the presence or absence of this RAR~2 isoform. Here, I show for the very first time, that the regenerating spinal cord of the adult newt expresses this ~2 receptor isoform, and inhibition of retinoid signaling through this specific receptor with a selective antagonist inhibits tail and spinal cord regeneration. This provides the first evidence for a role of this receptor in this process. Another species capable of CNS ~~generation in the adult is the invertebrate, " Lymnaea stagnalis. Although RA has been detected in a small number of invertebrates (including Lymnaea), the existence and functional roles of the retinoid receptors in most invertebrate non-chordates, have not been previously studied. It has been widely believed, however, that invertebrate non-chordates only possess the RXR class of retinoid receptors, but not the RARs. In this study, a full-length RXR cDNA has been cloned, which was the first retinoid receptor to be discovered in Lymnaea. I then went on to clone the very first full-length RAR eDNA from any non-chordate, invertebrate species. The functional role of these receptors was examined, and it was shown that normal molluscan development was altered, to varying degrees, by the presence of various RXR and RAR agonists or antagonists. The resulting disruptions in embryogenesis ranged from eye and shell defects, to complete lysis of the early embryo. These studies strongly suggest an important role for both the RXR and RAR in non-chordate development. The molluscan RXR and RAR were also shown to be expressed in the adult, nonregenerating eNS, as well as in individual motor neurons regenerating in culture. More specifically, their expression displayed a non-nuclear distfibution, suggesting a possible non-genomic role for these 'nuclear' receptors. It was shown that immunoreactivity for the RXR was present in almost all regenerating growth cones, and (together with N. Farrar) it was shown that this RXR played a novel, non-genomic role in mediating growth cone turning toward retinoic acid. Immunoreactivity for the novel invertebrate RAR was also found in the regenerating growth cones, but future work will be required to determine its functional role in nerve cell regeneration. Taken together, these data provide evidence for the importance of these novel '. retinoid receptors in development and regeneration, particularly in the adult nervous system, and the conservation of their effects in mediating RA signaling from invertebrates to vertebrates.
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Département de linguistique et de traduction
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L’objectif général de cette thèse était d’explorer le développement personnel de jeunes à risque de délinquance et de décrochage scolaire à travers leur participation à un programme d’intervention psychosociale nommé « Bien dans mes Baskets » (BdmB). Ce programme utilise le basketball parascolaire comme outil d’intervention et il a comme particularité qu’une bonne partie de ses entraineurs-intervenants détiennent une formation professionnelle en travail social ou domaines connexes. Cette thèse présente les résultats de trois études faisant partie d’un projet de recherche plus vaste portant sur l’évaluation du programme BdmB. Une première étude a exploré le processus de transfert, à d’autres domaines d’activités, des habiletés de vie ciblées par le programme BdmB. Des entretiens semi-directifs ont été réalisés auprès de 14 anciens participants et sept anciennes participantes du programme. Nos résultats suggèrent que trois principaux facteurs semblent avoir joué un rôle dans le processus de transfert des habiletés de vie développées au sein de BdmB, soit la présence de contextes favorisant l’apprentissage expérientiel, la valeur relative accordée aux différents domaines d’activités et la trajectoire de vie. Il ressort également de nos données qu’au-delà du processus de transfert sur une base individuelle, il est possible qu’un transfert puisse s’opérer dans la communauté. L’objectif de la deuxième étude était d’explorer comment et dans quelle mesure les expériences au sein de BdmB ont pu servir de levier au processus d’empowerment. Des entretiens semi-directifs ont été réalisés auprès de sept anciennes participantes de BdmB. Nos résultats suggèrent que la pratique sportive, combinée à une intervention psychosociale, peut contribuer au développement d’un plus grand contrôle sur sa vie. Cette amélioration serait la résultante cumulative de divers apprentissages, dont le développement et le transfert d’habiletés de vie et la capacité à résister aux influences externes négatives présentes dans leurs milieux de vie respectifs, ainsi que l’impact positif des expériences vécues au sein de BdmB sur la persévérance scolaire et les aspirations professionnelles. Une troisième étude avait pour objectif d’évaluer l’impact du programme BdmB sur le sentiment d’appartenance à l’école et la perception de soutien social. Un devis quasi expérimental a été utilisé pour évaluer l’impact du programme auprès des athlètes-étudiants(es) actuels. Le groupe d’intervention était composé des athlètes-étudiants de BdmB et les groupes de comparaison étaient constitués des étudiants de la même école ne participant pas au programme et pratiquant ou non un autre sport. Les individus ont été sondés à deux reprises à l’aide d’un questionnaire auto administré sur une période de deux années scolaires. Les résultats de l’étude indiquent que le groupe BdmB a développé un meilleur sentiment d’appartenance et a perçu un meilleur soutien social par rapport aux groupes de comparaison.