Dans un contexte de réchauffement climatique, la fonction « puits » de carbone (C) des tourbières est susceptible de changer en fonction « source » libérant ainsi de grandes quantités de C dans l’atmosphère sous l’effet d’une dégradation accrue de la matière organique (MO). Ainsi cette thèse se sont attachés à étudier la dynamique de dégradation de la MO labile (MOL) et récalcitrante (MOR) en fonction de 3 facteurs contrôlant (le niveau relatif de la nappe, un réchauffement simulé in situ et des variations saisonnières) dans la tourbière ombrotrophe du Forbonnet (25, Jura). Basés sur des analyses biogéochimiques et moléculaires de (i) la tourbe (50cm d’épaisseur), (ii) la fraction organique extractible à l’eau (WEOM) et (iii) les eaux piézométriques, les résultats acquis montrent une dégradation accrue de la MOL (e.g. polysaccharides et produits de son hydrolyse tels que le fructose,le glucose et le saccharose) et de la MOR sous l’effet d’une diminution du niveau de la nappe. Les conditions hydrologiques affectent également les processus de dégradation (sénescence et un éventuel priming effect) et d’humification de la MO pouvant conditionner le piégeage potentiel de laMOL. Après 13 mois d’incubation, l’effet du réchauffement simulé se traduirait par une hausse de l’évapotranspiration dans la condition la plus humide, là où l’étude de la WEOM indique une moindre dégradation de la MOL en surface contrairement aux niveaux profonds. Enfin, les travaux portant sur la dynamique saisonnière du C des eaux piézométriques soulignent le besoin d’intégrer la notion d’interactions entre facteurs contrôlant le cycle du C dans les tourbières pour comprendre leur réponse aux changements climatiques. / In a global warming context, the carbon (C) "sink" function of peatlands may switch to a source function releasing large amounts of C into the atmosphere as a result of an increased decay of organic matter (OM). Thus, these works have focused on the decay dynamics of labile OM and recalcitrant OM (respectively LOM and ROM) according to 3 controlling factors (water-level changes, an in situ simulated warming and seasonally changes) in the “le Forbonnet” bog (25, Jura). Based on biogeochemical and molecular analyses (i) on peat, (ii) on water extractable OM and (iii) on free waters, results suggest an increased decay of LOM (e.g. polysaccharides and its hydrolysis products such as fructose, glucose and sucrose) and MOR under water level changes. Hydrological conditions also affect decay (senescence and an eventual priming effect) and humification processes that can facilitate LOM capture. After 13 months of incubation, simulated warming would lead to an increase of evapotranspiration in the wettest condition where WEOM study indicates a lower LOM decay on the contrary to the deeper peat levels. Studies on the seasonal dynamic of C on free waters underline the need to integrate interactions between factors controlling the C cycle in peatlands to understand their responses to climate change.

Made available in DSpace on 2016-04-28T20:19:24Z (GMT). No. of bitstreams: 1 2009 - Tania Regina Frota Vasconcellos Dias.pdf: 1299945 bytes, checksum: bc480eb77d63e5679f8be1adc04aedfc (MD5) Previous issue date: 2009-04-27 / In the last years, it was consolidated the importance that micro and small business represent in the economic and social setting of the country. At the same time, it is incontrovertible that the competitiveness is essential to the inclusion of Brazilian companies in markets more and more globalized. In that context, the interest in entrepreneurship grows. Entrepreneurial competences take the lead role. The aim of this study is to identify how such entrepreneurial competences take part in the history of the life of the agents of the winning companies of the 2006 and 2007 Corporate TOP Awards and what made them successful people. This research has, as basis, the taxonomy presented by Vergara (2006): as far as to the ends, exploratory and descriptive and, to the means, bibliographic, documental, and multiple cases studies. The data were gathered through a semi-structured questionnaire and sent to the awarded people, after they were personally contacted. The treatment and the data analysis were developed through the Method of Content Analysis, mixed categorical analysis where they were defined, a priori, based on the theory of Man and Lau (2000). The sample of the first study, related to the winners of the 2006 Corporate TOP Award, had five out of six entrepreneurs; and, the sample of the second study, related to the winners of the 2007 Corporate TOP Award, had six out of eight. Seven entrepreneurial competences area stood out in the study. The results show that three of the seven competences area considered relevant and common: Conceptual Competence, Strategic Competence and Support Competence; and, they represent 58.77% of the related frequency, emphasizing the first and the second ones that stand for 24.85% of the total. It can be inferred that there is a relation between the entrepreneurship s success and the inherent competences of the entrepreneurs, such as independence and self-assurance, persistence, pride and self-esteem, creativity, innovation, intuition, taking moderate risks, perfectionism, and calling. The recognition of market opportunities is the key to the development of the activities where the derivation of occupation is the starting point. The major emphasis of its project is related to the obsessive search for quality and sustainability, aiming to the constant satisfaction of its clients. They are innovative in the Schumpeterian style, in the way that they don t necessarily associate innovation with scientific knowledge. They prospered once they had created in the market a new business strategy, as they have a high intelligence level for success. / Nos ?ltimos anos, consolidou-se a import?ncia que micro e pequenas empresas representam no cen?rio econ?mico e social do pa?s. Ao mesmo tempo, ? incontroverso ser a competitividade fundamental para a maior inser??o das empresas brasileiras em mercados cada vez mais globalizados. Nesse contexto, cresce o interesse pelo empreendedorismo. Compet?ncias empreendedoras assumem papel de destaque. O objetivo deste estudo foi identificar como tais compet?ncias empreendedoras fazem parte da hist?ria de vida dos agentes das empresas ganhadoras do Pr?mio TOP Empresarial nos anos de 2006 e 2007 e que os teria tornado bem sucedidos. Esta pesquisa adota como base a taxionomia apresentada por Vergara (2006): quanto aos fins, explorat?ria e descritiva e, quanto aos meios, bibliogr?fica, documental e de estudo de casos m?ltiplos. Os dados foram colhidos atrav?s de um question?rio semi-estruturado, enviado por e-mail aos agraciados, ap?s serem contatados pessoalmente. O tratamento e a an?lise de dados se desenvolveram atrav?s do M?todo de An?lise de Conte?do, an?lise categorial mista, onde as categorias foram definidas, a priori, com base na teoria de Man e Lau (2000). A amostra do primeiro estudo, referente aos ganhadores do Pr?mio TOP Empresarial 2006, se constitui de cinco dentre os seis empreendedores. J? a amostra do segundo estudo, ganhadores do Pr?mio TOP Empresarial 2007, se constituiu de seis dentre os oito empreendedores. Destacaram-se sete ?reas de compet?ncias empreendedoras no estudo. Os resultados mostram que tr?s destas s?o consideradas relevantes e comuns: Compet?ncia Conceitual, Compet?ncia Estrat?gica e Compet?ncia de Suporte e representam 58,77% de freq??ncia relativa, com destaque para a primeira, que representa 24,85% deste total. Depreende-se que muito do sucesso do empreendimento est? relacionado ?s compet?ncias inerentes a esses empreendedores, como: independente e autoconfian?a; persistente, orgulho e auto-estima, criatividade, inova??o, intui??o, assun??o de riscos moderados, perfeccionismo e voca??o. O reconhecimento de oportunidades de mercados se mostra fundamental, para o desenvolvimento de suas atividades, onde a deriva??o de ocupa??o ? a base. O grande destaque do seu produto est? relacionado ? busca obsessiva pela qualidade e sustentabilidade, visando ? constante satisfa??o dos seus clientes. S?o inovadores no estilo schumpeteriano, dado que, n?o associam necessariamente a inova??o ao conhecimento cient?fico. Prosperam ao criarem no mercado uma nova estrat?gia de neg?cios, pois t?m um alto n?vel de intelig?ncia para o sucesso.

Le but de la thèse est de mesurer la section efficace de production de quarks top-antitop dans le canal lepton + jets dans l'expérience ATLAS au Grand collisionneur de hadrons (LHC). L'analyse utilise les données des collisions proton-proton à 7 TeV collectées en 2010 avec une luminosité intégrée de 33,7 pb-1. La sélection des événements est basée sur la signature de la topologie top-antitop avec 1 électron ou muon, une grande énergie transverse manquante et au moins 4 jets. Le fond QCD multijets est mesuré avec les données elles-mêmes par une "Méthode Matricielle". Trois méthodes sont utilisées pour mesurer le fond W+jets, la méthode d’asymétrie de charge, la méthode de Berends-Giele et une méthode combinant les deux précédentes. Les autres bruits de fond sont estimés à partir MC. Le nombre d'événements de signal top-antitop est obtenu en ajustant la distribution du nombre de jets étiquetés b, en mesurant simultanément l'efficacité d‘étiquetage des quarks b. La section efficace top-antitop est mesurée à 148,1±34,9 pb. Elle est compatible avec la prédiction du Modèle Standard à l’ordre NNLO calculée par le logiciel Hathor. Elle est également en accord avec les mesures par d'autres méthodes. Avec plus de données sur les collisions en 2011, on peut s'attendre à une mesure plus précise de la section efficace top-antitop. / The essential purpose of the thesis is to measure the top pair cross section in lepton+jets channels in the Atlas experiment at Large Hadron Collider (LHC). The analysis is using the proton-proton collision data at 7 TeV collected in 2010 with a luminosity of 33.7 pb-1. The event selection is based on the signature of ttbar topology with 1 electron or muon, large missing transverse energy and at least 4 jets. The QCD multijet background is measured with the data driven “Matrix Method”. Three data driven methods are applied to measure the W+jets background, the charge asymmetry method, the Berends Scaling method and the method combining both. Other backgrounds are estimated from MC.The number of signal ttbar events are obtained by fitting the distribution of the number of b-tagged jet, when the b-tagging efficiency is simultaneously fitted. The ttbar cross section is measured to be 148.1±34.9 pb. It is consistent with the Standard Model prediction at NNLO calculated by Hathor tool. It also agrees with the measurements from other methods. With more collision data in 2011, one can expect a more precise measurement on ttbar cross section.

<p>In this thesis we analyze the phase of the heavy symmetric top and the tippe top. These tops are two examples of physical systems for which the usefulness of integrals of motion and invariant manifolds, in phase space picture analysis, can be illustrated</p><p>In the case of the heavy symmetric top, simplified proofs of stability of the vertical rotation have been perpetuated by successive textbooks during the last century. In these proofs correct perturbations of integrals of motion are missing. This may seem harmless since the deduced threshold value for stability is correct. However, perturbations of first integrals are essential in rigorous proofs of stability of motions for both tops.</p><p>The tippe top is a toy that has the form of a truncated sphere equipped with a little peg. When spun fast on the spherical bottom its center of mass rises above its geometrical center and after a few seconds the top is spinning vertically on the peg. We study the tippe top through a sequence of embedded invariant manifolds to unveil the structure of the top's phase space. The last manifold, consisting of the asymptotic trajectories, is analyzed completely. We prove that trajectories in this manifold attract solutions in contact with the plane of support at all times and we give a complete description of their stability/instability properties for all admissible choices of model parameters and of the initial conditions.</p> / Report code: LiU-TEK-LIC-2004:35.

Das Top-Quark zerfällt, bevor es hadronisiert. Bevor die Spin-Konfiguration des Top-Quarks durch Prozesse der Starken Wechselwirkung geändert werden kann, wird sie direkt an die Zerfallsprodukte des Top-Quarks weitergegeben. Rückschl usse auf den Spin des Top-Quarks können über Winkelverteilungen der Zerfallsprodukte gezogen werden. Die Spins von Top-/Anti-Top-Quark (tt) Paaren sind, gemäß der Vorhersage durch das Standardmodell, korreliert. Der Grad der Korrelation ist sensitiv auf den Spin und die Produktionsmechanismen des Top-Quarks. Die Messung der Spin-Korrelation bietet einen Test der Vorhersagen. Effekte von Physik jenseits des Standardmodells können sich in Abweichungen der vorhergesagten Spin-Korrelation manifestieren. In dieser Arbeit wird die Spin-Korrelation von Top-Quark Paaren, die bei einer Schwerpunktsenergie von sqrt(s) = 7 TeV produziert und mit dem ATLAS Detektor rekonstruiert wurden, gemessen. Der Datensatz entspricht einer integrierten Luminosität von 4.6 fb-1. Die Top-Quarks wurden im Lepton+Jets Zerfallskanal mittels eines kinematischen Likelihood-Fits, der eine Trennung der leichten up- und down-Typ Quarks aus dem t->bW->bqq Zerfall erlaubt, rekonstruiert. Die Spin-Korrelation wird über die Verteilung des Azimutalwinkels zwischen zwei Top-Quark Spin-Analysatoren im Laborsystem gemessen. Sie wird als Grad fSM der Spin-Korrelation, wie sie im Rahmen des Standardmodells berechnet wird, angegeben. Die Messungen ergeben fSM(DeltaPhi(geladenes Lepton, down-Typ Quark)) = 1.53 ± 0.14 (stat.) ± 0.32 (syst.); fSM(DeltaPhi(geladenes Lepton, b-Quark)) = 0.53 ± 0.18 (stat.) ± 0.49 (syst.); fSM(DeltaPhi(kombiniert)) = 1.12 ± 0.11 (stat.) ± 0.22 (syst.). Die Ergebnisse stimmen mit der Berechnung im Rahmen des Standardmodells, fSM = 1.0, überein.

Det finns två typer av goodwill, den första typen är internt upparbetad goodwill och den andra typen är goodwill som uppkommer vid förvärv av företag. Fokus i denna uppsats kommer att ligga på den förvärvade goodwill, som kan upplevas som en svart låda då det kan vara oklart vad posten faktiskt består av. Förvärvad goodwill kan definieras på olika sätt av företagen, i den akademiska världen har främst två perspektiv identifierats, top-downperspektivet och bottom-upperspektivet. Ur den första synvinkeln ses goodwill som en restpost och ur den andra synvinkeln kan goodwill ses som en summa av de komponenter som posten består av. Genom att betrakta dessa perspektiv är tanken att få en inblick i hur företagen väljer att redovisa sin goodwill. Det kan vara lättare sagt än gjort, teori och praktik går inte alltid hand i hand. Det finns ett glapp mellan hur praktiker jobbar med goodwill och teoretikers åsikt om posten. Varför det finns meningsskiljaktigheter växer successivt fram under studiens gång. Det finns än så länge bara ett fåtal studier som behandlar själva begreppet goodwill och dess olika perspektiv samt hur företagen ser på goodwill. För att försöka bidra till ökad förståelse på detta område, har vi i denna uppsats undersökt om teorin och praktiken kommit varandra närmare. Det främsta syftet med studien är att ta reda på om företag inom bemanningsbranschen definierar sin goodwill olika i sina årsredovisningar. För att undersöka detta på ett begripligt sätt har tre professionella respondenter intervjuats i ett försök att klargöra komplexiteten av posten.   Slutsatsen är att det inte går att identifiera vilket perspektiv som används i en årsredovisning på grund av att dessa är väldigt standardiserade, vilket gör att det blir svårt för intressenten att utläsa särskilt mycket information om goodwillposten.  Det alternativ som kändes mest relevant att använda och som skulle hjälpa oss att kunna få klarhet i vår frågeställning, var att vända sig till en urvalsgrupp av representanter på området. Den analys som efterföljde resulterade i att vi kunde konstatera att samtliga svarande på det praktiska området såg goodwillposten mer eller mindre som en restpost. Ingen värdering eller starkare reflektion gjordes kring det andra teoretiska perspektivet. Sammanfattningsvis vågar vi påstå att det inte skett någon märkbar förändring som gjort att teori och praktik närmat sig varandra. / There is two ways to understand goodwill. Number one, internally generated goodwill and number two, acquired purchase goodwill. The main topic for this research is acquired purchase goodwill. Many people believe that goodwill is a sort of black box.  It is unclear what goodwill actually is. There is no limit on how you can define acquired purchase goodwill. In academia we talk about two perspectives, top-down perspective and bottom-up perspective. The first perspective sees goodwill as a residual and the second perspective sees goodwill as a sum of its components. When you put on these two glasses, the idea is that you may be able to see how businesses account for their goodwill. It is easier said than done, many times theory and practice does not get along. There is a big space between the theories on how you work with goodwill in the reality. Only a few have studied the definition of goodwill. Because of that we really wanted to investigate this phenomenon. We have analyzed if the gap between theory and reality has been reduced. The purpose of this study is to investigate if the staffing companies define goodwill different in their annual reports. The tool we have used is to interview professional accountants to get their opinion. The conclusion is that the annual report is quite standardized which means it is difficult to understand what goodwill actually is. Everybody we interviewed have the same opinion, that goodwill is a residual. They made no reflections or additions on that subject. In summary, we know now that after our study, no big change has been made between theory and practice.

Longwall Top Coal Caving (LTCC) technology has great potential for more efficient mining of Australian thick coal seams. LTCC can potentially double (or greater) the longwall recoverable tonnes, per metre of gateroad development and improve the safety standards in longwall operation. Accurate cavability assessment of the coal seam is the key pre-requisite for successful application of LTCC method. Although some cavability criteria were developed in previous studies, their shortcomings limit their application. Apart from the lack of suitable cavability criterion, the caving principles and mechanisms in longwall operation (and LTCC) is still not well understood. The main objectives of this research work were: 1. to improve the general understanding about the caving mechanisms involved in LTCC operation, 2. to develop a new cavability assessment criterion, and 3. to characterise and classify the caving behaviour in selected Australian longwall operations. For this study a combination of analytical, observational and empirical engineering methods were used to reduce the shortcoming of individual design methods. For analytical study, the Distinct Element Method (DEM) was selected for computational analysis as the most suitable technique for this type of study. For observational methods, the size distribution of particles in goaf was used as a monitoring measure for caving performance evaluation and this method was performed in three Australian longwall operations (Ulan, West Wallsend and Broadmeadow). The Empirical assessment was performed by using the results of observational/computational analyses along with basic geological/geotechnical data from selected mine sites to back analyse and re-evaluate the results. The most significant outcomes of this study include: 1. a new cavability assessment system (Top Coal Cavability Rating, TCCR) that was developed based on computational analysis and by back analysis of past LTCC experience in China, 2. Improved understanding of caving mechanism, deformation mechanism and drawing mechanism of top coal in LTCC method, 3. advanced numerical models (UDEC, 3DEC and PFC models) that not only can be used for future research but can also be employed for LTCC design purposes, 4. characterisation and classification of caving behaviour in three Australian longwall operations. The results of this study can be effectively used by Australian coal industry in feasibility and design studies of LTCC operation. The new cavability criterion can be used to identify and quantify the major risks that may be involved in LTCC application.

No description available.

Le quark top à été découvert en 1995 par les collaboration dzero~et cdf~au TeVatron. De part sa masse très grande de l'ordre de 172.5 GeV, il est difficile à produire et certaines de ces propriétés nécéssitent encore d'être étudiées avec précision. Le Modèle Standard prévoit deux types de production pour le quark top qui sont la production par paires et la production solitaire ("single top"). Si les modes de production par paires sont maintenant bien connus, sa production solitaire l'ai beaucoup moins notamment à cause de faibles taux de production et de forts bruits de fond. Cette thèse est consacrée à la mesure de la section efficace de production d'un quark top en association avec un boson W dans le canal dilepton au près de l'expérience ATLAS placée sur le Large Hadron Collider (LHC) au CERN. Deux analyses sont présentées dans ce document. La première mesure mondiale de ce processus, réalisée à l'aide des premiers 35 pb-1 de données, est tout d'abord exposée. Cette mesure se veut simple et robuste et utilise au maximum les données pour les diverses estimations de bruits de fond venant entacher la mesure. Une seconde analyse utilisant cette fois toutes les données 7 TeV recueillies en 2011(4.7 fb-1) est aussi présentée. Cette dernière mesure, de sensitivité beaucoup plus grande, fait appel à des techniques de discrimination poussées utilisant des Arbres de Decision Boostés ainsi qu'un traitement statistique plus performant que celui utilisé précédemment. La valeur mesurée de la section efficace W+t est ensuite utilisée afin de contraindre les secteurs électrofaibles du quark top via une mesure de l'élement de matrice CKM |V_tb|. / The top quark was discovered in 1995 by the D0 and CDF experiments at the TeVatron. Due to its great mass, close to 172.5 GeV, the top quark is difficult to produce and some of its properties still need to be deeply studied. The Standard Model predicts two production modes which are the top quark pair production and the single top production. The top pair production is now well known unlike the single top production which exhibits lower production rates and higher background contamination. This thesis is devoted to the determination of the cross-section of the associated production of a top quark with a W boson in the dilepton channel using the ATLAS detector at the Large Hadron Collider (LHC). Two analyzes are presented in this document. The first analysis corresponds to the first measurement ever of the W+t process using the 2010 ATLAS dataset (35 pb-1 of data). This measurement is simple and robust and uses as much as possible data driven techniques for the various estimates of background contamination. A second analysis that uses the whole 7 TeV dataset collected during 2011 (4.7 fb-1) is also presented. This last study uses advanced discrimination techniques and refined statistical treatments in order to increase the global sensitivity of the measurement. The measured value of the W+t cross section is then used to constrain the top quark electroweak sector via a measurement of the CKM matrix element | V_tb |.

La présente thèse constitue le compte rendu de l'analyse menée auprès du détecteur ATLAS du LHC et concernant la recherche de processus de création résonante de nouvelles particules se désintégrant en une paire de quarks top. Elle s'articule principalement autour de la notion de jet de hadrons, dont l'identification et la reconstruction est un enjeu capital pour toute mesure essayant de signer l'apparition de quarks top lors de processus de collisions proton-proton. Après une mise en contexte portant sur une description générale des caractéristiques théoriques et expérimentales que présente la thématique de la détection de jets de hadrons dans le détecteur ATLAS, nous présentons une première tentative de validation de la méthode d'étalonnage hadronique local, dont le but est de corriger ces jets des imprécisions de mesure engendrées par le détecteur. Dans la deuxième partie du document figure l'analyse menée sur les 14~fb$^{-1}$ de données de collisions proton-proton à $sqrt{s} = 8$~TeV, récoltées lors de l'année 2012, à la recherche de l'apparition de processus de création résonante de nouvelle particules extit{lourdes} dans le spectre de masse invariante top-antitop. Pour des particules lourdes, les quarks tops produits lors de la désintégration de ces dernières possèdent une impulsion très grande par rapport à leur masse et la désintégration de tels quarks top conduit souvent à une topologie dans l'état final dite og boostée fg, où le quark top, s'il se désintègre de manière hadronique, est très souvent reconstruit comme un seul jet, de large paramètre de rayon. Le présent travail de thèse propose ainsi une étude préliminaire pour reconstruire et identifier le plus précisément possible ce type de signal, en se basant sur l'étude de la sous-structure des jets de hadrons. / This report presents the analysis conducted with the ATLAS experiment at the LHC and searching for resonnant production of new particles decaying into a pair of top quarks. Top quark reconstruction is mainly build upon the notion of hadronic jets, whose identification and reconstruction is a crucial issue for any measure trying to sign top quark decays from proton-proton collisions processes. After a general description of the theoretical and experimental features of jet reconstruction in the ATLAS detector, we present a first attempt to validate the local hadronic calibration method, which aim at correcting the measurement of these objects from inaccuracies caused by detector effects. In the second part, we present the analysis conducted on 14~fb$^{-1}$ of proton-proton collision data at $ sqrt{s}=$8~TeV collected during the year 2012 and searching for resonnant creation of new extit{heavy} particles in top-antitop invariant mass spectrum. For heavy particles, the quarks produced in the decay of the latter have a high impulsion with respect to their mass and those top quark decays often results in a so called og boosted fg topology, where the hadronically decaying top quark is often reconstructed as a single jet of large radius parameter. In this context, we present a preliminary study to reconstruct and identify as precisely as possible this type of boosted topologies, based on the study of jet substructure.