Global ETD Search

111	Basotho oral poetry at the beginning of the 21st century Tsiu, M. W. (Moruti William), 1944- 31 October 2008 (has links) Largely based on material recorded during an internationally sponsored inter-university research tour through the Sesotho speaking area of southern Africa in August 2000, this thesis explores the state of the Basotho oral poetry, the dithoko `praise poems', the difela `mine workers' chants' and the diboko `family odes' at the beginning of the 21st century. Unlike the classical dithoko which were inspired by the wars or the battles in which the Basotho fought as well as cannibalism, those composed at the beginning of the 21st century are inspired by socio-economic and political situations of the poets. Lack of wars has resulted in the poets turning the praising to their chiefs and themselves. Changing socio-economic conditions inspired the difela compositions. The diboko though still a living tradition among the rural Basotho are not adhered to by some who are affected by modernism. Performance of the three oral genres has shifted from the natural settings such as the battlefield, working parties, traditional courts, assemblies, etc., to organized annual festivals such as Morija Arts & Cultural Festival which constitute the Basotho's `popular culture'. The subject-matter and themes of the dithoko have shifted from warfare to traditional chiefs, current heroic deeds of the poets, current political situations and religion. The difela are characterized by inclusion of new subject-matter. The diboko still play an important function as carriers of the names of the ancestors, the tribal idiosyncrasy of the clan and the history associated with the clan's establishment. The three Basotho oral genres demonstrate an emergence of a new phenomenon whereby one genre penetrates another, a phenomenon which may be called `migration of texts'. The last chapter explores the insights emanating from the entire research, and discusses suggestions on what should be done to ensure that the Basotho oral genres are maintained and improved. The video footage of the poets recorded at various places of the Free State and Lesotho have contributed to the success of the research. The thesis serves as a contribution to the Basotho's dynamic oral poetry on which scholars will hopefully do further research in the near future. / African Languages / D. Litt et Phil. (African Languages) Thoko 'praise poem' Dithoko 'praise poems' Sefela 'mine workers' chants' Difela 'mine workers' chants' Seboko 'family ode/clan praise' Diboko 'family odes/clan praises' Seroki 'a poet' Diroki 'the poets' Mosotho 'a Mosotho' Basotho 'the Basotho' Performance Subject-matter Theme Penetration/migration Oral genres 398.2049639772 Sotho (African people) -- Folklore
112	Contrôle de la dynamique de la leucémie myéloïde chronique par Imatinib / Control of the dynamics of chronic myeloid leukemia by Imatinib Benosman, Chahrazed 18 November 2010 (has links) Dans ce travail de recherche, nous sommes intéresses par la modélisation de l'hématopoïèse. Les cellules souches hématopoïétiques (CSH) sont des cellules indifférenciées de la moelle osseuse, possédant la capacité de se renouveler et de se différencier (pour la production des globules rouges, globules blancs et les plaquettes). Le processus de l'hématopoïèse souvent révèle des irrégularités qui causent les maladies hématologiques. En modélisant la leucémie myéloide chronique (LMC), une maladie hématologique fréquente, nous représentons l'hématopoïèse des cellules normales et cancéreuses par un système d'équations différentielles ordinaires (EDO). L'homéostasie des cellules normales et différente de l'homéostasie des cellules cancéreuses, et dépend de quelques lignées des cellules normales et cancéreuses. Nous analysons la dynamique globale du modèle pour obtenir les conditions de régénération de l'hématopoïèse ou bien la persistance de la LMC. Nous démontrons aussi que la coexistence des cellules normales et cancéreuses ne peut avoir lieu pour longtemps. Imatinib est un traitement de base de la LMC, avec un dosage variant de 400 à 1000 mg par jour. Certains patients présentent des réponses différentes à la thérapie, pouvant être hématologique, cytogénétique et moléculaire. La thérapie échoue dans deux cas: le patient demande un temps plus long pour réagir, alors il s'agit d'une réponse suboptimale; ou bien le patient résiste après une bonne réponse initiale. Pour déterminer le dosage optimal, nécessaire à la réduction des cellules cancéreuses, nous représentons les effets de la thérapie par un problème de contrôle optimal. Notre but est de minimiser le cout du traitement et le nombre des cellules cancéreuses. La réponse suboptimale, la résistance et le rétablissement sont alors obtenus suivant l'influence de l'imatinib sur les taux de division et de mortalité des cellules cancéreuses. Nous étudions par ailleurs l'hématopoïèse selon un modèle structuré en age, décrivant l'évolution des CSH normales et cancéreuses. Nous démontrons que le taux de division des CSH cancéreuses joue un rôle important dans la détermination du contrôle optimal. En contrôlant la croissance des cellules normales et cancéreuses avec compétition inter spécifique, nous démontrons que le dosage optimal dépend de l'homéostasie des CSH cancéreuses. / Modelling hematopoiesis represents a feature of our research. Hematopoietic stem cells (HSC) are undifferentiated cells, located in bone marrow, with unique abilities of self-renewal and differentiation (production of white cells, red blood cells and platelets).The process of hematopoiesis often exhibits abnormalities causing hematological diseases. In modelling Chronic Myeloid Leukemia (CML), a frequent hematological disease, we represent hematopoiesis of normal and leukemic cells by means of ordinary differential equations (ODE). Homeostasis of normal and leukemic cells are supposed to be different and depend on some lines of normal and leukemic HSC. We analyze the global dynamics of the model to obtain the conditions for regeneration of hematopoiesis and persistence of CML. We prove as well that normal and leukemic cells can not coexist for a long time. Imatinib is the main treatment of CML, with posology varying from 400 to 1000 mg per day. Some affected individuals respond to therapy with various levels being hematologic, cytogenetic and molecular. Therapy fails in two cases: the patient takes a long time to react, then suboptimal response occurs; or the patient resists after an initial response. Determining the optimal dosage required to reduce leukemic cells is another challenge. We approach therapy effects as an optimal control problem to minimize the cost of treatment and the level of leukemic cells. Suboptimal response, resistance and recovery forms are obtained through the influence of imatinib onto the division and mortality rates of leukemic cells. Hematopoiesis can be investigated according to age of cells. An age-structured system, describing the evolution of normal and leukemic HSC shows that the division rate of leukemic HSC plays a crucial role when determining the optimal control. When controlling the growth of cells under interspecific competition within normal and leukemic HSC, we prove that optimal dosage is related to homeostasis of leukemic HSC. Modélisation de l'hématopoièse Maladies hématologiques Leucémie myéloide chronique Imatinib Dynamique des populations Analyse variationnelle et optimisation Contrôle des systèmes d'EDO et EDP Analyse numérique Simulations numériques Hematopoietic stem cells (HSC) Hematopoiesis Homeostasis Chronic myeloid leukemia (CML) Dynamical systems Ordinary differential equations (ODE) Global asymptotic stability Partial differential equations (PDE) Optimization theory and applications Numerical simulations
113	Dynamic Cabin Air Contamination Calculation Theory Lakies, Marcel January 2019 (has links) (PDF) In this report an equation is derived to calculate the dynamic effect of primary and secondary aircraft cabin air contamination. The equation is applied in order to understand implications and hazards. Primary contamination is from an outside source in form of normal low level contamination or high level contamination in a failure case. Secondary contamination originates from deposited material released into the cabin by a trigger event. The dynamic effect is described as an initial value problem (IVP) of a system governed by a nonhomogeneous linear first order ordinary differential equation (ODE). More complicated excitations are treated as a sequence of IVPs. The ODE is solved from first principles. Spreadsheets are provided with sample calculations that can be adapted to user needs. The method is not limited to a particular principle of the environmental control system (ECS) or contamination substance. The report considers cabin air recirculation and several locations of contamination sources, filters, and deposit points (where contaminants can accumulate and from where they can be released). This is a level of detail so far not considered in the cabin air literature. Various primary and secondary cabin contamination scenarios are calculated with plausible input parameters taken from popular passenger aircraft. A large cabin volume, high air exchange rate, large filtered air recirculation rate, and high absorption rates at deposit points lead to low contamination concentration at given source strength. Especially high contamination concentrations would result if large deposits of contaminants are released in a short time. The accuracy of the results depends on the accuracy of the input parameters. Five different approaches to reduce the contaminant concentration in the aircraft cabin are discussed and evaluated. More effective solutions involve higher implementation efforts. The method and the spreadsheets allow predicting cabin air contamination concentrations independent of confidential industrial input parameters. ddc:620 info:eu-repo/classification/ddc/629.13 Luftfahrt Luftfahrzeug Passagierflugzeug Flugzeugkabine Aeronautics Airplanes Air--Pollution Aircraft cabins Luftverschmutzung Trikresylphosphat aircraft cabin cabin air ECS tricresyl phosphate TCP initial value problem IVP ordinary differential equation ODE air contamination concentration contaminant dynamics spreadsheet
114	Using ClassPad-technology in the education of students of electricalengineering (Fourier- and Laplace-Transformation) Paditz, Ludwig 09 May 2012 (has links) By the help of several examples the interactive work with the ClassPad330 is considered. The student can solve difficult exercises of practical applications step by step using the symbolic calculation and the graphic possibilities of the calculator. Sometimes several fields of mathematics are combined to solve a problem. Let us consider the ClassPad330 (with the actual operating system OS 03.03) and discuss on some new exercises in analysis, e.g. solving a linear differential equation by the help of the Laplace transformation and using the inverse Laplace transformation or considering the Fourier transformation in discrete time (the Fast Fourier Transformation FFT and the inverse FFT). We use the FFT- and IFFT-function to study periodic signals, if we only have a sequence generated by sampling the time signal. We know several ways to get a solution. The techniques for studying practical applications fall into the following three categories: analytic, graphic and numeric. We can use the Classpad software in the handheld or in the PC (ClassPad emulator version of the handheld). info:eu-repo/classification/ddc/510 ddc:510
115	Leading-colour two-loop QCD corrections for top-quark pair production in association with a jet at a lepton collider Peitzsch, Sascha 03 May 2023 (has links) In dieser Arbeit wird die Berechnung der farbführenden Zweischleifen-QCD-Korrekturen für die Top-Quark-Paarproduktion mit einem zusätzlichen Jet an einem Lepton-Collider präsentiert. Das Matrixelement wird in Vektor- und Axial-Vektorströme zerlegt und die Ströme werden weiter in Dirac-Spinorstrukturen und Formfaktoren zerlegt. Die Formfaktoren werden mit Projektoren extrahiert. Die auftretenden Feynmanintegrale werden mittels IBP-Identitäten und Dimensionsverschiebungstransformationen durch eine Basis quasi-finiter Masterintegrale in 6−2ϵ Dimensionen ausgedrückt. Die Mehrheit der Feynmanintegrale gehört zu einer Doppelbox-Integralfamilie. Die Berechnung der Masterintegrale erfolgt durch numerisches Lösen von Differentialgleichungen in kinematischen Invarianten. Asymptotische Reihenentwicklungen der Masterintegrale in der Top-Quarkmasse werden verwendet, um die Anfangsbedingungen für die numerischen Lösungen der Differentialgleichungen zu bestimmen. Die führenden Terme dieser Entwicklung werden mit der Expansion-by-Regions-Methode berechnet. Höhere Reihenkoeffizienten werden durch die Anwendung einer Differentialgleichung auf einen Ansatz für die Reihenentwicklung bestimmt. Die renormierten Formfaktoren und die farbführende Zweischleifenamplitude werden an einem Referenzphasenraumpunkt zu hoher Präzision numerisch ausgewertet. Die Resultate werden mit elektroschwachen Ward-Identitäten und durch numerische Vergleiche der IR-Singularitäten mit der erwarteten Singularitätsstruktur überprüft. / In this work, the calculation of the leading-colour two-loop QCD corrections for top-quark pair production with an additional jet at a lepton collider is presented. The matrix element is decomposed into vector and axial-vector currents and the currents are further decomposed into Dirac spinor structures and form factors. The form factors are extracted with projectors. The Feynman integrals are reduced to a quasi-finite basis in 6 − 2ϵ dimensions using IBP identities and dimension-shift transformations. The majority of master integrals belong to a double-box integral family. The master integrals are computed by numerically solving systems of differential equations in the kinematic invariants. Asymptotic expansions of the master integrals in the top-quark mass variable are used to calculate initial conditions for the numerical differential equation solutions. The leading terms of the expansion are obtained with the expansion by regions and the higher orders are calculated by solving a system of equations obtained from applying the differential equation onto an ansatz of the expansion. The renormalized form factors and the leading-colour two-loop amplitude are evaluated numerically to high precision at a benchmark phase space point. The results are cross-checked with electroweak Ward identities and by numerically comparing the IR singularities with the expected singularity structure. Hochenergiephysik Quantenchromodynamik QCD Zweischleifenkorrekturen Feynmanintegrale Leptonencollider QCD Störungsrechnung Elektron-Positron-Beschleuniger high energy physics quantum chromodynamics QCD two-loop QCD corrections Feynman integrals lepton collider perturbative QCD numerical ODE solutions electron–positron collider 530 Physik ddc:530
116	Asymptotic Analysis of Models for Geometric Motions Gavin Ainsley Glenn (17958005) 13 February 2024 (has links) <p dir="ltr">In Chapter 1, we introduce geometric motions from the general perspective of gradient flows. Here we develop the basic framework in which to pose the two main results of this thesis.</p><p dir="ltr">In Chapter 2, we examine the pinch-off phenomenon for a tubular surface moving by surface diffusion. We prove the existence of a one parameter family of pinching profiles obeying a long wavelength approximation of the dynamics.</p><p dir="ltr">In Chapter 3, we study a diffusion-based numerical scheme for curve shortening flow. We prove that the scheme is one time-step consistent.</p> Numerical analysis Partial differential equations partial differential equations (PDE) motion by mean curvature Mean Curvature Flow surface diffusion models gradient flows diffusion generated motion codimension-2 pinch-off dynamics consistency estimates heat equation axisymmetric surface diffusion Geometric PDEs one-parameter family singularity formation Numerical analysis. convergence rate Differential equations. Ordinary Differential Equations (ODE)
117	Metapopulation dynamics of dengue epidemics in French Polynesia / Dynamique métapopulationelle des épidémies de dengue en Polynésie française Teissier, Yoann 22 May 2017 (has links) La dengue circule en Polynésie française sur un mode épidémique depuis plus de 35 ans. Néanmoins, en dépit de la taille relativement faible de la population de Polynésie française, la circulation de la dengue peut persister à de faibles niveaux pendant de nombreuses années. L’objectif de ce travail de thèse est de déterminer si l'épidémiologie de la dengue dans le système insulaire de la Polynésie française répond aux critères d’un contexte de métapopulation. Après avoir constitué une base de données regroupant les cas de dengue répertoriés sur les 35 dernières années, nous avons réalisé des analyses épidémiologiques descriptives et statistiques. Celles-ci ont révélé des disparités spatio-temporelles distinctes pour l’incidence de la dengue des archipels et des îles, mais la structure de l'épidémie globale à l’échelle de la Polynésie française pour un même sérotype ne semble pas être affectée. Les analyses de la métapopulation ont révélé l'incidence asynchrone de la dengue dans un grand nombre d’îles. Celle-ci s’observe plus particulièrement par la différence de dynamique de l’incidence entre les îles plus peuplées et celles ayant une population plus faible. La taille critique de la communauté nécessaire à la persistance de la dengue n’est même pas atteinte par la plus grande île de Polynésie Française, Tahiti. Ce résultat suggère que la dengue peut uniquement persister grâce à sa propagation d’île en île. L'incorporation de la connectivité des îles à travers des modèles de migration humaine dans un modèle mathématique a produit une dynamique de la dengue davantage en adéquation avec les données observées, que les tentatives de modélisation traitant la population dans son ensemble. Le modèle de la métapopulation a été capable de simuler la même dynamique que les cas de dengue observés pour l'épidémie et la transmission endémique qui a suivi pour la période de 2001 à 2008. Des analyses complémentaires sur la différenciation de l'incidence de la maladie et de l'infection seront probablement instructives pour affiner le modèle de métapopulation de l'épidémiologie de la dengue en Polynésie française. / Dengue has been epidemic in French Polynesia for the past 35 years. Despite the relatively small population size in French Polynesia, dengue does not disappear and can persist at low levels for many years. In light of the large number of islands comprising French Polynesia, this thesis addresses the extent to which a metapopulation context may be the most appropriate to describe the epidemiology and persistence of dengue in this case. After compiling a database of dengue cases over the last 35 years, we used a number of descriptive and statistical epidemiological analyses that revealed distinct spatio-temporal disparity in dengue incidence for archipelago and islands. But the global structure of the epidemics of the same serotype were not affected. Metapopulation analyses revealed asynchronous dengue incidence among many of the islands and most notably larger islands lagged behind the smaller islands. The critical community size, which determines dengue persistence, was found to exceed even the largest island of Tahiti, suggesting that dengue can only exist by island-hopping. Incorporation of island connectedness through patterns of human migration into a mathematical model enabled a much better fit to the observed data than treating the population as a whole. The metapopulation model was able to capture to some extent the epidemic and low level transmission dynamics observed for the period of 2001-2008. Further analyses on differentiating incidence of disease and infection will likely prove informative for the metapopulation model of dengue epidemiology in French Polynesia. Dengue Épidémies Métapopulation Polynésie française Modélisation SEIR Transmission endémique Persistance Infection Migration Population Circulation insulaire Population critique Connections insulaires Modèle Logiciel R Études statistiques Identification des facteurs de risques Densité de la population Vecteur Aedes aegypti Géographie insulaire Milieu tropical Distance de vol du vecteur Immunité de la population Densité vectorielle Taux de récupération de l’hôte Mortalité du vecteur Cycle de transmission des virus Arbovirus Dynamique de la dengue Simulations Dynamique épidémique Dengue Epidemics Metapopulation French Polynesia Modeling SEIR Endemic transmission Persistence Infection Migration Population Insular circulation Critical population Insular connections Model Ordinary differential equation (ODE) R software Statistical study Risk factor identification Population density Vector Aedes aegypti Insular geography Tropical environment Vector flight distance Population immunity Vector density Host recovery rate Vector mortality Virus transmission cycle Arbovirus Dengue dynamic Simulations Epidemic dynamics 614.4

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