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Détermination des paramètres cosmologiques dans le cadre du modèle de Friedmann-Lemaîtres / Determination of the cosmological parameters in the framework of the Friedmann-Lemaître modelChbib, Dyaa 15 December 2017 (has links)
Un siècle après le modèle d'univers de Friedmann-Lemaître, les observations le confortent avec une constante cosmologique $\Lambda$ et une composante de matière sombre (noire) sans pression (poussière) et froide dominant celle baryonique, que l'on désigne par modèle $\Lambda$CDM. L'accélération de l'expansion de l'Univers confirmée par le diagramme de Hubble des supernovae en 1998 impose une valeur strictement positive à la constante cosmologique. Mes travaux de thèse se focalisent sur l'estimation des valeurs de paramètres cosmologiques du modèle standard en utilisant la technique de corrélation nulle. Cette approche présente l'avantage d'être plus robuste que les techniques usuelles. Ce travail a consisté aussi à modéliser des échantillons de l'événement quasar ainsi que l'événement supernova, une extrapolation adaptée du premier. Ce qui a permis de générer des échantillons conformes aux hypothèses des modèles, afin de valider les approches statistiques. Nous avons exploité les données du Sloan Digital Sky Survey (SDSS) pour les quasars, et celles du SuperNova Legacy Survey (SNLS) et du SDSS-II pour les supernovae. Les inférences statistiques ont conduit à un univers spatialement fermé et une présence de matière noire plus faible. Dans le cadre d'une prochaine application de cette technique, elle sera utilisée pour contraindre les modèles d'énergie noire. De même, l'utilisation des amas de galaxies observées grâce à l'effet de Sunyaev Zel'dovich, servira d'échantillon cosmologique. Une telle étude pourra contribuer à apporter un élément de réponse à la validité du rôle supposé des neutrinos massifs dans la formation des amas dans l'ère primordiale de l'Univers. / A century after the Universe model of Friedmann-Lemaître, the observations comfort it with a cosmological constant $\Lambda$ and a dark matter component without pressure (dust) and cold dominating the baryonic one, which is denoted by $\Lambda$CDM model. The acceleration of the expansion of the Universe confirmed by the Hubble diagram of the supernovae in 1998 imposes a strictly positive value on the cosmological constant. My thesis work focuses on the estimation of the cosmological parameters values of the standard model using the null correlation technique. This approach has the advantage of being more robust than the usual techniques. This work deals with modelling samples of the quasar event and the supernova event, which enables us to generate samples in order to validate the statistical approaches. We used data from the Sloan Digital Sky Survey (SDSS) for quasars, and the SuperNova Legacy Survey (SNLS) and SDSS-II for supernovae. The Statistical inferences suggest a Universe spatially Closed and a weaker presence of dark matter than that in the Standard model. Such a statistical analysis can be used to constrain dark energy models. Application of this technique might be useful for analyzing of clusters of galaxies observed through the effect of Sunyaev Zel'dovich, in view of deriving the cosmological model and provide an answer to the question of the contribution of massive neutrinos in the formation of clusters in the primordial era of the Universe.
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Optimal liquidation in dark pools in discrete and continuous timeKratz, Peter 30 August 2011 (has links)
Wir studieren optimale Handelsstrategien für einen risikoaversen Investor, der bis zu einem Zeitpunkt T ein Portfolio aufzulösen hat. Dieser kann auf einem traditionellen Markt (dem "Primärmarkt") handeln, wodurch er den Preis beeinflusst, und gleichzeitig Aufträge in einem Dark Pool erteilen. Dort ist die Liquidität nicht öffentlich bekannt, und es findet keine Preisfindung statt: Aufträge werden zum Preis des Primärmarkts abgewickelt. Deshalb haben sie keinen Preiseinfluss, die Ausführung ist aber unsicher; es muss zwischen den Preiseinflusskosten am Primärmarkt und den indirekten Kosten durch die Ausübungsunsicherheit im Dark Pool abgewogen werden. In einem zeitdiskreten Handelsmodell betrachten wir ein Kostenfunktional aus erwarteten Preiseinfluss- und Marktrisikokosten. Für linearen Preiseinfluss ist dieses linear-quadratisch und wir erhalten eine Rekursion für die optimale Handelsstrategie. Eine Position in einem einzelnen Wertpapier wird langsam am Primärmarkt abgebaut während der Rest im Dark Pool angeboten wird. Für eine Position in mehreren Wertpapieren ist dies wegen der Korrelation der Wertpapiere nicht optimal. Tritt im eindimensionalen Fall adverse Selektion auf, so wird die Attraktivität des Dark Pools verringert. In stetiger Zeit impliziert die Liquidationsbedingung eine Singularität der Wertfunktion am Endzeitpunkt T. Diese wird im linear-quadratischen Fall ohne adverse Selektion durch den Grenzwert einer Folge von Lösungen einer Matrix Differentialgleichung beschrieben. Mit Hilfe einer Matrixungleichung erhalten wir Schranken für diese Lösungen, die Existenz des Grenzwertes sowie ein Verifikationsargument mittels HJB Gleichung. Tritt adverse Selektion auf, ergeben umfangreiche heuristische Betrachtungen eine ungewöhnliche Struktur der Wertfunktion: Sie ist ein quadratisches "Quasi-Polynom", dessen Koeffizienten in nicht-trivialer Weise von der Position abhängen. Wir bestimmen dieses semi-explizit und führen ein Verifikationsargument durch. / We study optimal trading strategies of a risk-averse investor who has to liquidate a portfolio within a finite time horizon [0,T]. The investor has the option to trade at a traditional exchange (the "primary venue") which yields price impact and to place orders in a dark pool. The liquidity in dark pools is not openly displayed and dark pools do not contribute to the price formation process: orders are executed at the price of the primary venue. Hence, they have no price impact, but their execution is uncertain. The investor thus faces the trade-off between the price impact costs at the primary venue and the indirect costs resulting from the execution uncertainty in the dark pool. In a discrete-time market model we consider a cost functional which incorporates the expected price impact costs and market risk costs. For linear price impact, it is linear-quadratic and we obtain a recursion for the optimal trading strategy. For single asset liquidation, the investor trades out of her position at the primary venue, with the remainder being placed in the dark pool. For multi asset liquidation this is not optimal because of the correlation of the assets. In the presence of adverse selection in the one dimensional setting the dark pool is less attractive. In continuous time the liquidation constraint implies a singularity of the value function at the terminal time T. In the linear-quadratic case without adverse selection it is described by the limit of a sequence of solutions of a matrix differential equation. By means of a matrix inequality we obtain bounds of these solutions, the existence of the limit and a verification argument via HJB equation. In the presence of adverse selection the value function has an unusual structure, which we obtain via extensive heuristic considerations: it is a "quasi-polynomial" whose coefficients depend on the asset position in a non-trivial way. We characterize the value function semi-explicitly and carry out a verification argument.
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Astrophysical aspects of dark matter direct detection / Aspects astrophysiques de la détection directe de matière sombreMagni, Stefano 13 November 2015 (has links)
Cette thèse traite des aspects astrophysiques de la détection directe (DD) de matière noire sous forme de WIMPs. On se concentre sur les contraintes observationnelles des quantités astrophysiques qui influent sur l'interprétation des résultats expérimentaux de DD.On revoit tout d'abord le formalisme de la DD et on résume les résultats expérimentaux les plus importants ainsi que les méthodes statistiques généralement utilisés pour interpréter les données. On reproduit ensuite les limites expérimentales sur la section efficace spin-indépendante. On résume l'ensemble des hypothèses astrophysiques couramment utilisées dans le modèle de halo standard et on décrit l'influence de ses paramètres sur les limites.Pour inscrire la DD dans un cadre plus général, on résume les concepts les plus importants de la dynamique Galactique. En particulier, on revoit comment modéliser la Galaxie avec des modèles de masse, tout en soulignant les relations entre les différentes quantités astrophysiques. On décrit des procédures qui permettent d'obtenir des distributions dans l'espace des phases de la matière noire qui soient consistantes avec un profil de matière noire et un potentiel Galactique donné. La plus simple procédure étant basée sur l'équation d'Eddington, on discute ses limites d'applicabilité. On revoit dans les détails la littérature récente concernant les déterminations et les incertitudes des quantités astrophysiques liées à la DD et des paramètres Galactiques fondamentaux.Dans la dernière partie de la thèse on s'intéresse aux estimations récentes de la vitesse d'échappement publiées par la collaboration RAVE. On étudie dans les détails les implications de ces résultats sur les expériences de DD. Pour cela on prends en compte les corrélations entre les quantités astrophysiques importantes pour la DD, et en assumant le modèles de masse de RAVE on calcule la distribution de matière noire dans l'espace des phases avec l'équation d'Eddington. Du fait des valeurs plus élevés de la densité locale de matière noire, cette procédure conduit à des limites plus contraignantes par rapport a celles standards. / This thesis deals with the astrophysical aspects of the direct detection of WIMP dark matter (DMDD). In particular, it focuses on the observational constraints on the astrophysical quantities relevant for DMDD, which impact on the interpretation of the experimental results.We review the formalism of DMDD and we summarize some of the main experimental results in this domain and the statistical methods usually employed to interpret the data, reproducing the associated constraints on the parameter space relevant for spin-independent WIMP-nucleon interaction. We summarize the set of astrophysical assumptions usually employed, the Standard Halo Model, and we point out the impact of variations in its parameters on such limits.We outline the main concepts of the dynamics of our galaxy that allow to put the astrophysics related to DMDD in a wider framework. In particular, we review the description of the Galaxy through Milky Way mass models (MWMM), pointing out how the astrophysical quantities are related. We describe some procedures to obtain dark matter phase-space distributions consistent with given dark matter profile and Galactic potential, the simplest being Eddington equation, of which we discuss the limits of applicability. We review in detail the recent literature on the main determinations and uncertainties of the astrophysical quantities relevant for DMDD and of the fundamental Galactic parameters.In the most original part of this thesis we focus on the recent estimates of the local Galactic escape speed published by the RAVE collaboration. We study in detail the implications of these results for the spin-independent interpretation of DMDD experiments. We take into account the correlations between the astrophysical quantities relevant for DMDD calculations, and from the assumed MWMM we compute the dark matter phase-space distribution using Eddington equation, which provides a self-consistent physical connection between the two. This procedure leads to more constraining exclusion curves with respect to the standard ones, due to higher values of the local dark matter density.
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ECOEFICIÊNCIA EM SISTEMAS DE PRODUÇÃO DE FRANGOS DE CORTEDecian, Michel January 2018 (has links)
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Previous issue date: 2018 / The consumption of chicken meat as a source of animal protein is increasing. Largescale confinement systems are responsible for meeting this demand. As a result, the
consumption of inputs and the environmental changes that these systems provide intensify. The production chain of Brazilian broiler chicken is characterized by a system of integration
between producer and the agroindustry, and both are inserted in a globalized market, where the imported inputs and export much of the production is exported to foreign markets. To evaluate the economic and environmental performance of production systems responsible for representing this food supply, an eco-efficiency assessment was made. The eco-efficiency assessment addressed two methods for quantifying environmental impacts and valuation of product systems, Life Cycle Assessment (LCA) and Economic Value Added (EVA). The approach comprised the stages of agricultural production, breeding and fattening of chickens.
Four products in three different systems were evaluated, Griller, Broiler and heavy broiler
chickens produced in Negative pressure automated dark house aviaries, and the same chickens produced in Conventional positive pressure aviaries. Also, for comparison an alternative system of positive pressure was used to represent the production of organic chickens that serves a niche market but receives attention for studies in other countries. The Functional Unit (UF) was 1 kg of live chicken ready to be shipped to the slaughterhouse, and the method for Life Cycle Impact Assessment (AICV) was done with CML 2. The results showed that most of the impacts comes from the agricultural stage of grain production for the rations, and from the use of electric power to feed the equipment of the barracks. Conventional systems presented negative results for the generation of economic value and environmental impacts like the Dark House systems.
Chickens produced in organic systems positively outperformed the other products in terms of economic valuation but had results of potential environmental impact much higher. It was
possible to conclude that for conventional systems special attention needs to be paid regarding the return on investment, especially in relation to rates for capital remuneration, to provide new ventures that, in addition to smaller environmental impacts, can also generate greater economic profit. / O consumo da carne de frango como fonte de proteína animal é crescente em todo
mundo. Os sistemas de produção de confinamento em larga escala são responsáveis por atender
essa demanda. Em função disso o consumo de insumos e as trocas ambientais que estes sistemas
proporcionam se intensificam. A cadeia produtiva do frango de corte no Brasil é caracterizada
em sua maioria por sistemas de integração entre produtores e agroindústrias, e estão inseridos
em um mercado globalizado onde importam insumos e exportam boa parte da produção para
mercados externos. Para avaliar o desempenho econômico e ambiental dos sistemas de
produção responsáveis por representar essa oferta de alimentos, uma avaliação de ecoeficiência
foi feita. A avaliação de ecoeficiência abordou dois métodos para quantificar os impactos
ambientais e a valoração dos sistemas de produto, a Avaliação do Ciclo de Vida (ACV) e o
Valor Econômico Agregado (EVA). A abordagem foi do berço ao portão dos aviários,
compreendendo as etapas de produção agrícola, fábrica de ração e engorda dos frangos. Quatro
produtos em três sistemas diferentes foram avaliados, os frangos Griller, Broiler e pesados
produzidos em aviários automatizados de pressão negativa Dark House, e os mesmos frangos
produzidos em aviários de pressão positiva convencionais. Ainda para comparação, um sistema
alternativo de pressão positiva foi utilizado representando a produção de frangos orgânicos que
atende um determinado nicho de mercado e recebe atenção para estudos similares em outros
países. A Unidade Funcional (UF) usada é de 1 kg de frango vivo pronto para embarcar para o
abatedouro, e a Análise de Impacto do Ciclo de Vida (AICV) foi feita com o método CML 2
baseline. Os resultados mostraram que a maior parte dos impactos vem da etapa agrícola da
produção de grãos usados na fabricação das rações, e por seguinte do uso de energia elétrica
para alimentar os equipamentos dos aviários. Os sistemas convencionais apresentaram
resultados negativos para geração de valor econômico e impactos ambientais similares aos
sistemas Dark House. Os frangos produzidos em sistemas orgânicos superaram positivamente
os demais produtos quanto a valoração econômica, mas tiveram resultados de potencial impacto
ambiental muito acima em todas as categorias de impacto analisadas. Foi possível concluir que
para sistemas convencionais uma atenção especial precisa ser dada quanto ao retorno dos
investimentos, principalmente com relação as taxas para remuneração do capital, de forma a
proporcionar a novos empreendimentos que além de impactos ambientais menores também
possam gerar maior lucro econômico.
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Would you trust me if I lied to you in favor of charity? : The implication of Brand Trust when using Dark Patterns for charityAxelsson, Victoria January 2022 (has links)
Brand Trust is the trust consumers have in brands and have been previously proven to be affected negatively by dark patterns (i.e. design patterns used in websites to deceive their customers). This study is aimed to find out if Brand Trust is affected negatively by dark patterns when used for charity. The study is a between-group to determine Brand Trust based on six different scenarios (three using dark patterns for profit, three using dark patterns for charity) using the Brand Trust Scale that is divided into two dimensions, Fiability and Intentionality. This was measured in the form of two questionnaires. There were two groups that completed the questionnaires, one group that watched the scenarios for profit (for profit) and one that watched the scenarios for charity (for charity). The study consisted of 69 participants in total (37 completed the for-profit questionnaire; 32 completed the for-charity questionnaire). The hypothesis was that the group for-charity would have a higher value of Brand Trust. The results showed no significant difference between the two groups to support the hypothesis, however, an exploration of the results indicated that men have a higher Brand Trust in the dimension Intentionality and that the participants who valued themselves as really good at being source critical had a higher Brand Trust in the dimension Fiability. / Det förtroende konsumenter har för varumärken kallas varumärkesförtroende och har tidigare visat sig påverkas negativt av dark patterns som är designmönster som webbsidor använder för att lura sina kunder. Denna studie syftar till att ta reda på om varumärkesförtroendet fortfarande kommer att påverkas negativt om dark patterns används för välgörenhet. Studien är en mellangruppsstudie för att fastställa Brand Trust baserat på sex olika scenarier (tre använder dark patterns för vinst, tre använder dark patterns för välgörenhet) med hjälp av Brand Trust Scale som är uppdelad i två dimensioner, Fiability och Intentionality. Detta mättes i form av två frågeformulär. Det var två grupper som fyllde i frågeformulären, en grupp som tittade på scenarierna för vinst (för vinst) och en som tittade på scenarierna för välgörenhet (för välgörenhet). Studien bestod av totalt 69 deltagare (37 fyllde i frågeformuläret för vinst; 32 fyllde i frågeformuläret för välgörenhet). Hypotesen var att gruppen för välgörenhet skulle ha ett högre värde av Brand Trust. Resultaten visade ingen signifikant skillnad mellan de två grupperna för att stödja hypotesen, dock indikerade en utforskning av resultaten att män har ett högre varumärkesförtroende i dimensionen Intentionality och att deltagarna som värderade sig själva som riktigt bra på att vara källkritiska hade en högre Brand Trust i dimensionen Fiability.
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Le tourisme en Syrie, passé, présent, futur : entre résilience et réinvention / Tourism in Syria, past, present, future : between resilience and reinventionKassouha, Zeid Alkhail 18 April 2018 (has links)
Alors que le conflit en Syrie continue sa course dévastatrice depuis mars 2011, cette recherche s’inscrit dans une démarche prospective visant à envisager le post-conflit. Après une analyse de la situation touristique et politique de la Syrie, avant et pendant le conflit, notre travail aboutit à une série de constats et de prévisions qui permettent de dessiner le contour d’un tourisme post-conflit dans le pays. Pour compléter notre analyse nous avons eu recours au comparatisme avec les cas de la Bosnie-Herzégovine et de la Croatie. Les deux pays ayant connu des conflits dans les années 1990, cette démarche nous a permis d’y observer le contexte post-conflit avec plus de recul. Les questions du devenir du patrimoine existant et de l’émergence d’un « nouveau patrimoine » issu du conflit font partie des sujets auxquels nous nous sommes intéressés ainsi qu’à l’évolution de l’interprétation de ces différents patrimoines au fil du temps (« à chaud »/ « à froid »). Nous nous sommes intéressés en parallèle aux nouvelles formes de tourisme qui pourraient accompagner le retour de la paix, notamment le "dark tourism", caractéristique du contexte post-conflit. Le résultat prend la forme de scenarii décrivant les différents aboutissements possibles du conflit en cours en Syrie et leurs implications respectives sur le futur du tourisme dans le pays. / While the harrowing conflict in Syria has been enduring since March 2011, this research aims nonetheless to foresee the aftermath of the war through a forward-looking approach. After an analysis of the situation in Syria, before and during the war, from a touristic and political point of view, our work results in a series of observations and forecasts that allow us to draw the outlines of a post-conflict tourism in the country. More specifically and in order to complete our analysis, we used a comparative framework to study the examples of Bosnia and Herzegovina, as well as Croatia. Given that both countries have lived through conflict in the 1990s, this approach enabled us to observe the post-conflict context with a longer lapse of time. The questions related to the future of heritage sites, the emergence of a “new heritage” resulting from the conflict itself, and the changes over time in the interpretation of these different forms of heritage (“hot/cold interpretation”) were among the main issues that we have treated in this dissertation. We also took a major interest in the appearance of new forms of tourism that might accompany the return of peace, especially the “dark tourism”, typical of the post-conflict context. The results are presented in the form of scenarios that describe the different possible outcomes of the current conflict in Syria and their respective implications for the future of tourism in the country.
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Samband mellan emotionell intelligens, personlighet och arbetsprestation : en tvärsnittsstudie som validerar den svenskaversionen av TEIQue-SF / Relationship between emotional intelligence, personality and work performanceHjalmarsson, Annica January 2018 (has links)
Emotionell intelligens har studerats under flertalet år, i olika länder, och har definierats på olika sätt. Egenskapen emotionell intelligens består av fyra dimensioner; emotionality, self-control, well-being och sociability, och mäts genom mätinstrumentet TEIQue-SF. TEIQue-SF har uppnått god validitet som mätverktyg på olika språk, och valideras för första gången på svenska genom denna studie. Tidigare forskning har uppvisat flertalet samband mellan egenskapen emotionell intelligens (EI), personlighet och arbetsprestation. Dessa tillsammans har dock inte undersökts i Sverige. Syftet med att genomföra denna studie var att undersöka sambanden mellan Trait Emotional Intelligence Questionnaire Short Form (TEIQ-SF), Mini-International Personality Inventory Pool-6 (Mini-IPIP6), Short Dark Triad (SD3) och Individual Work Performance Questionnaire (IWPQ) ytterligare, samt att ta reda på vilka personlighetsdrag och dimensioner inom självupplevd individuell arbetsprestation som bäst förklarar variansen inom TEIQue-SFs dimensioner. Studien genomfördes som en tvärsnittsstudie med 228 svenska deltagare (M = 34 år, SD = 12.6, range 16-71 år, 66% kvinnor) med genomsnittlig arbetslivserfarenhet på 14 år (SD = 11.5). Förväntat resultat var att neuroticism skulle korrelera negativt med TEIQue-SF fyra dimensioner, vilket uppnåddes även i denna studie. Positiva samband med Task performance och Contextual performance fanns mellan samtliga dimensioner av EI. Regressionsanalyser visade även att neuroticism hade negativt samband vid förklaring av varians i samtliga dimensioner tillhörande TEIQue-SF. En preliminär slutsats är att TEIQue-SF visat på teoretiskt och empiriskt rimliga samband med relevanta variabler, och kan anses vara validerat bland yngre personer med relativt hög utbildningsnivå. / Emotional intelligence has been defined differently throughout studies for many years in several countries. The trait emotional intelligence consists of four dimensions; emotionality, self-control, well-being and sociability, and is measured by the TEIQue-SF measuring instrument. TEIQue-SF has achieved good validity as a measurement tool in different languages and is now validated in Swedish through this study. Previous research has shown liaisons between the emotional intelligence (EI), personality and work performance. However, these together have not been investigated in Sweden. The purpose of this study was to investigate correlations between Trait Emotional Intelligence Questionnaire Short Form (TEIQ-SF), Mini-International Personality nventory Pool-6 (Mini-IPIP6), Short Dark Triad (SD3) and Individual Work Performance Questionnaire (IWPQ), and to find out which personality traits and dimensions within self-perceived individual work performance best explain the variance within TEIQue-SF dimensions. The study was conducted as a cross-sectional study with 228 Swedish participants (M = 34 years, SD = 12.6, range 16-71 years, 66% women) with an average work experience of 14 years (SD = 11.5). Expected result was that neuroticism would correlate negatively with TEIQue-SF four dimensions, which was also achieved in this study. Positive correlation with Task Performance and Contextual Performance was found between all dimensions of EI. Regression analysis also showed that neuroticism had a negative relation to explanation of variance in all imensions of TEIQue-SF. A preliminary conclusion is that TEIQue-SF has shown theoretical and empirically reasonable relation to relevant variables and can be considered validated among younger people with relatively high educational levels.
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Equação de Klein-Gordon não-linear e superuidos relativísticos.LINS, Aline Nascimento. 09 October 2018 (has links)
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Previous issue date: 2017-02 / O conceito de Matéria Escura surgiu para explicar uma anomalia na curva de rotação de galáxias espirais, desde então, pesquisadores de todo o mundo vêm tentando detectar a partícula que compõe tal matéria. Sem sucesso nas detecções, surgiram algumas teorias para explicar a existência tanto da Matéria Escura quanto da Energia Escura, responsável pela expansão acelerada do Universo. Neste trabalho apresentamos uma dessas teorias. Aqui sugerimos que o Universo se comporta de uma maneira diferente com a qual estamos acostumados, para isso tzemos uso da relatividade geral e da equação não-linear de Klein-Gordon, e então admitimos que o Universo está imerso em um superfluido relativístico para assim podermos explicar teoricamente Matéria Escura e Energia Escura. / The concept of Dark Matter arises to explain an anomaly in the rotation curve of spiral
galaxies, since then, researchers around the world have been trying to detect the particle
that composes this matter. Without success in the detections, some theories appeared to
explain the existence of both Dark Matter and Dark Energy, the last one is responsible
for the accelerated expansion of the Universe. In this dissertation we present one of
these theories. Here we suggest that the Universe behaves in a di erent way with which
we are accustomed, for this we have made use of the general relativity and the
Klein-Gordon's nonlinear equation, and then we admit that the Universe is immersed in
a relativistic superfluid so we can theoretically explain Dark Matter and Dark Energy.
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Dynamics of Warps and Lopsidedness in Spiral GalaxiesSaha, Kanak January 2007 (has links) (PDF)
No description available.
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Análise da abundância e detecção direta num modelo de matéria escuraSantos, Antonio Carlos Oliveira 25 April 2015 (has links)
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Previous issue date: 2015-04-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work we consider a minimal local abelian gauge group extension with charge
B - 3Le anomaly-free. We add a right-handed singlet Majorana fermion plus a neutral and
charged scalars, responsible for spontaneous symmetry breaking and a charged singlet scalar
to provide a connection between the electron and the Majorana fermion. The aim of this
model is provide a low energy theory to Dark matter as a Majorana fermion. There are
several evidences of a new kind of a non-baryonic matter but its nature and properties are
not well established. So, based in some experiments (in particular those that main focus
is the direct detection), we are going to constraint some parameters of the model to test
its feasibility in this context. We have used a computational program called micrOMEGAs
(based on CalCHEP) to compute the abundance and scattering cross section between dark
matter and nucleon and compare with the experimental constraints arising from Planck
(abundance) and LUX (scattering cross section). We show that the results support the
restrictions imposed by the observations providing future perspectives for this extension,
like indirect detection of dark matter. / Nesta dissertação consideramos uma extensão abeliana mínima local, de carga B-3Le, livre de anomalias, onde foi introduzido um férmion de majorana de mão direita juntamente com um novo bóson escalar, responsável pela quebra espontânea da simetria local, e um escalar carregado conectando a família de léptons ao férmion de majorana. Este modelo tem por objetivo fornecer uma teoria de baixas energias para a matéria escura atribuída a um férmion de majorana. Logo, baseado em alguns experimentos (em particular aqueles cujo principal objetivo é a detecção direta de uma possível nova partícula atribuída à esta matéria), iremos vincular os parâmetros de nosso modelo a fim de verificar sua aplicabilidade neste senário. Com isto, utilizaremos o programa computacional micrOMEGAS (que utiliza o CalcHEP) a fim de calcular alguns observáveis do modelo, tais como a abundância e secção transversal de choque do espalhamento elástico entre a matéria escura e o nucleon e, em seguida, comparamos aos dados experimentais do Planck (abundância) e LUX (seção de choque). Resultados preliminares apontam para a validade do modelo diante das restrições impostas pelas observações, possibilitando a perspectiva de aplicação desta extensão em outros contextos, como os da detecção indireta da matéria escura.
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