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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Orienting Moduli Spaces of Flow Trees for Symplectic Field Theory

Karlsson, Cecilia January 2016 (has links)
This thesis consists of three scientific papers dealing with invariants of Legendrian and Lagrangian submanifolds. Besides the scientific papers, the thesis contains an introduction to contact and symplectic geometry, and a brief outline of Symplectic field theory with focus on Legendrian contact homology. In Paper I we give an orientation scheme for moduli spaces of rigid flow trees in Legendrian contact homology. The flow trees can be seen as the adiabatic limit of sequences of punctured pseudo-holomorphic disks with boundary on the Lagrangian projection of the Legendrian. So to equip the trees with orientations corresponds to orienting the determinant line bundle of the dbar-operator over the space of Lagrangian boundary conditions on the punctured disk. We define an  orientation of this line bundle and prove that it is well-defined in the limit. We also prove that the chosen orientation scheme gives rise to a combinatorial algorithm for computing the orientation of the trees, and we give an explicit description of this algorithm. In Paper II we study exact Lagrangian cobordisms with cylindrical Legendrian ends, induced by Legendrian isotopies. We prove that the combinatorially defined DGA-morphisms used to prove invariance of Legendrian contact homology for Legendrian knots over the integers can be derived analytically.  This is proved using the orientation scheme from Paper I together with a count of abstractly perturbed flow trees  of the Lagrangian cobordisms. In Paper III we prove a flexibility result for closed, immersed Lagrangian submanifolds in the standard symplectic plane.
72

Determinant factors affecting adherence to antiretroviral therapy among HIV infected patients in Addis Ababa

Abelti Eshetu Abdissa 09 September 2014 (has links)
The purpose of this study was to explore and describe the determinant factors affecting adherence to antiretroviral therapy among HIV infected patients in Addis Ababa, Ethiopia. A cross-sectional study design was used and data were collected by interviewing 290 study participants from two health facilities using structured questionnaire. The research finding revealed 80.0% of the study participants had optimal combined adherence to dose, schedule and dietary instructions in the past three days. And, the non adherence rate was 20.0%. In multivariate analysis only WHO clinical stage, change of ARV medication, knowledge about HIV disease and ART, and use of reminders were found to be independently associated with adherence to antiretroviral therapy. The most common reasons for missing HIV medications in the past one month were forgetfulness (35.1%), being busy with other things (17.5%), and running out of pills (10.5%). Adherence improving interventions should be emphasized to address multi-faceted problems. This study recommends setting of convenient appointment schedule, disclosure of one's HIV status, maintaining confidentiality of patient-related information, enhancing patient-provider relationship, use of reminders including SMS text messages, and engagement of PLHIV in adherence improving interventions through peer support, and providing regular health education to the PLHIV to improve adherence of patients to ART / Health Studies / M.A. (Public Health)
73

Multiple outlier detection and cluster analysis of multivariate normal data

Robson, Geoffrey 12 1900 (has links)
Thesis (MscEng)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: Outliers may be defined as observations that are sufficiently aberrant to arouse the suspicion of the analyst as to their origin. They could be the result of human error, in which case they should be corrected, but they may also be an interesting exception, and this would deserve further investigation. Identification of outliers typically consists of an informal inspection of a plot of the data, but this is unreliable for dimensions greater than two. A formal procedure for detecting outliers allows for consistency when classifying observations. It also enables one to automate the detection of outliers by using computers. The special case of univariate data is treated separately to introduce essential concepts, and also because it may well be of interest in its own right. We then consider techniques used for detecting multiple outliers in a multivariate normal sample, and go on to explain how these may be generalized to include cluster analysis. Multivariate outlier detection is based on the Minimum Covariance Determinant (MCD) subset, and is therefore treated in detail. Exact bivariate algorithms were refined and implemented, and the solutions were used to establish the performance of the commonly used heuristic, Fast–MCD. / AFRIKAANSE OPSOMMING: Uitskieters word gedefinieer as waarnemings wat tot s´o ’n mate afwyk van die verwagte gedrag dat die analis wantrouig is oor die oorsprong daarvan. Hierdie waarnemings mag die resultaat wees van menslike foute, in welke geval dit reggestel moet word. Dit mag egter ook ’n interressante verskynsel wees wat verdere ondersoek benodig. Die identifikasie van uitskieters word tipies informeel deur inspeksie vanaf ’n grafiese voorstelling van die data uitgevoer, maar hierdie benadering is onbetroubaar vir dimensies groter as twee. ’n Formele prosedure vir die bepaling van uitskieters sal meer konsekwente klassifisering van steekproefdata tot gevolg hˆe. Dit gee ook geleentheid vir effektiewe rekenaar implementering van die tegnieke. Aanvanklik word die spesiale geval van eenveranderlike data behandel om noodsaaklike begrippe bekend te stel, maar ook aangesien dit in eie reg ’n area van groot belang is. Verder word tegnieke vir die identifikasie van verskeie uitskieters in meerveranderlike, normaal verspreide data beskou. Daar word ook ondersoek hoe hierdie idees veralgemeen kan word om tros analise in te sluit. Die sogenaamde Minimum Covariance Determinant (MCD) subversameling is fundamenteel vir die identifikasie van meerveranderlike uitskieters, en word daarom in detail ondersoek. Deterministiese tweeveranderlike algoritmes is verfyn en ge¨ımplementeer, en gebruik om die effektiwiteit van die algemeen gebruikte heuristiese algoritme, Fast–MCD, te ondersoek.
74

Transfusions de globules rouges aux soins intensifs pédiatriques : épidémiologie et déterminants

Demaret, Pierre 08 1900 (has links)
Les transfusions de globules rouges (GR) sont fréquentes aux soins intensifs pédiatriques (SIP). Cependant, il n’y a pas de donnée récente sur les pratiques transfusionnelles aux SIP. Les objectifs de notre étude étaient 1) de décrire les pratiques transfusionnelles aux SIP du CHU Sainte-Justine en y déterminant la fréquence des transfusions de GR et en caractérisant les déterminants de ces transfusions, 2) de comparer ces pratiques avec celles observées il y a dix ans, et 3) d’évaluer le degré d’adhérence à la recommandation principale d’une large étude randomisée contrôlée, l’étude TRIPICU, laquelle proposait une pratique précise chez les patients stabilisés. Nous avons réalisé une étude monocentrique prospective observationnelle d’une durée d’un an. L’information requise a été extraite des dossiers médicaux. Les déterminants des transfusions ont été recherchés quotidiennement jusqu’à la première transfusion pour les cas transfusés, ou jusqu’à la sortie des SIP pour les cas non transfusés. Les justifications des transfusions déclarées par les médecins traitants ont été compilées à l’aide d’un questionnaire. Il y a eu 913 admissions consécutives durant la période d’étude, dont 842 ont été retenues. Au moins une transfusion a été donnée à 144 patients (17.1%). Le taux moyen d’hémoglobine avant la première transfusion était de 77.3±27.2 g/L. Les déterminants d’un premier événement transfusionnel à l’analyse multivariée étaient le jeune âge (< 12 mois), la présence d’une cardiopathie congénitale, un nadir d’hémoglobine ≤ 70 g/L, la gravité de la maladie, et certaines dysfonctions d’organe. Les trois justifications de transfusions les plus fréquemment évoquées par les médecins étaient une hémoglobine basse, un transport en oxygène insuffisant et une instabilité hémodynamique. La recommandation principale de l’étude TRIPICU a été appliquée dans 96.4% des premiers événements transfusionnels. En conclusion, les transfusions de GR sont fréquentes aux SIP. Jeune âge, cardiopathie congénitale, hémoglobine basse, gravité de la maladie et certaines dysfonctions d’organes sont des déterminants significatifs de transfusions de GR aux SIP. La plupart des premiers événements transfusionnels furent prescrits en accord avec les récentes recommandations. / Red blood cell (RBC) transfusions are common in pediatric intensive care unit (PICU). However, there are no recent data on transfusion practices in PICU. Our objective was 1) to describe transfusion practice in PICU, which means that we aimed to determine the incidence rate and to characterize the determinants of RBC transfusion, 2) to compare this practice with that observed ten years earlier, and 3) to estimate the compliance to the recommendation of a large randomized clinical trial, the TRIPICU study. We conducted a single center prospective observational study over a one-year period. Information was abstracted from medical charts. Determinants of transfusion were searched for daily until the first transfusion in transfused cases or until PICU discharge in non-transfused cases. The justifications for transfusions claimed by the attending physicians were assessed using a questionnaire. Among 913 consecutive admissions, 842 were enrolled. At least one RBC transfusion was given in 144 patients (17.1%). The mean hemoglobin level before the first transfusion was 77.3±27.2 g/L. The determinants of a first transfusion event retained in the multivariate analysis were young age (< 12 months), congenital heart disease, lowest hemoglobin level ≤ 70 g/L, severity of illness, and some organ dysfunctions. The three most frequently quoted justifications for RBC transfusion were a low hemoglobin level, intent to improve oxygen delivery, and hemodynamic instability. The main recommendation of the TRIPICU study was applied in 96.4% of the first transfusion events. In conclusion, RBC transfusions are frequent in PICU. Young age, congenital heart disease, low hemoglobin level, severity of illness and some organ dysfunctions are significant determinants of RBC transfusions in PICU. Most first transfusion events were prescribed according to recent recommendations.
75

Demonstrativní predeterminant v současné francouzštině a jeho fungování v textu / Demonstrative pre-determiner in current French and its functions in text

Bečvářová, Karolina January 2011 (has links)
demonstrative determiner - actualization - identification - reference - deixis - anaphora - cataphora - literary narative text Demonstrative determiner actualises and identifies a noun by designation the referent of this noun. Demonstrative determiner designates the referent in space (physical surroundings of the speaker), in context, or in common shared experience. In literary text, demonstrative determiner designates the referent in context by anaphora or cataphora, in some cases it designates the referent in fictional space.
76

Lipschitzovská zobrazení v rovině / Lipschitz mappings in the plane

Kaluža, Vojtěch January 2014 (has links)
In this thesis we consider an open question of Feige that asks whether there always exists a constantly Lipschitz bijection of an n2 -point subset of Z2 onto a regular grid [n] × [n] for every n ∈ N. We relate this question to an already resolved problem of the existence of a bounded positive measurable density in R2 that is not the Jacobian of any bilipschitz map. This problem was resolved by Burago and Kleiner [1], and independently, by McMullen [12]. We present the work of Burago and Kleiner, analyze its relation to Feige's problem and sug- gest a continuous formulation of Feige's question in a special case. Then we present the Burago-Kleiner density, make several observation about the properties of this density, and after that we construct a density that is everywhere nonrealizable as the Jacobian of a bilipschitz map. Subsequently, we discuss our continuous variant of Feige's question, provide several observation concerning it, and finally, we try to use the everywhere nonrealizable density constructed before to answer our continuous variant of Feige's question. However, this last task still remains incomplete. 1
77

Laplaciens des graphes sur les surfaces et applications à la physique statistique / Laplacians on graphs on surfaces and applications to statistical physics

Kassel, Adrien 24 June 2013 (has links)
Nous étudions le déterminant du laplacien sur les fibrés vectoriels sur les graphes et l'utilisons, en lien avec des techniques d'analyse complexe discrète, pour comprendre des modèles de physique statistique. Nous calculons certaines constantes de réseaux, construisons des limites d'échelles d'excursions de la marche aléatoire à boucles effacées sur les surfaces, et étudions certains champs gaussiens et processus déterminantaux. / We study the determinant of the Laplacian on vector bundles on graphs and use it, combined with discrete complex analysis, to study models of statistical physics. We compute exact lattice constants, construct scaling limits for excursions of the loop-erased random walk on surfaces, and study some Gaussian fields and determinantal processes.
78

Kapitalstrukturens påverkande variabler : en kvantitativ undersökning på svenska börsnoterade bolag / The determinants of capital structure : a quantitative study on listed Swedish companies

Rebolledo Montecinos, Daniela, Vallared, Powell January 2019 (has links)
Bolag står ständigt inför beslut kring val av finansiering och dessa beslut resulterar i bolagens kapitalstruktur. Kapitalstrukturen har undersökts sedan en lång tid tillbaka och flera olika teorier har växt fram. Än idag finns det dock ingen teori som kan förklara kapitalstrukturen på ett tillfredsställande sätt. Eftersom det inte finns några tydliga tecken på att det finns en optimal kapitalstruktur eller hur en sådan skulle kunna se ut, kan kapitalstrukturen variera. Denna undersökning har tagit fasta på två av de mest kända teorierna för att förklara kapitalstrukturen, trade-off teorin och pecking order teorin. Undersökningen har en tvärsnittsdesigns utformning och studerar hur lönsamhet, tillväxt, storlek, materiella tillgångar, likviditet, icke-skuld skattesköld och bransch påverkar kapitalstrukturen. Fokus ligger på den svenska marknaden och ämnar att kunna generalisera kring svenska börsnoterade bolag. Resultatet av denna undersökning bidrar till en ökad förståelse för kapitalstrukturen men vi är långt ifrån en fullständig bild av ämnet. Undersökningens slutsatser skiljer sig till viss del från tidigare forskning eftersom den hittar stöd för båda teorierna. Ingen av teorierna går dock att applicera i sin helhet på den svenska marknaden vilket tyder på att forskningsområdet fortfarande behöver utvecklas och nya idéer tillkomma. / Companies are constantly faced with making decisions regarding their choice of financing and these decisions result in the company’s capital structure. The capital structure has been studied for a long time and several theories have emerged. Still to this day there’s no theory that can explain the capital structure in a satisfying way. Since there are no clear signs that an optimal capital structure exists nor how one would look, the capital structure can vary. This study has its foundation in two of the most well-known theories that try to explain capital structures, the trade-off theory and the pecking order theory. This cross-sectional study examines how profitability, growth, size, tangible assets, liquidity, non-debt tax shield and industry affect capital structure. The focus lies on the Swedish market and intends to generalize about listed Swedish companies. The result of this paper contributes to an increased understanding of capital structure but we are far from a complete comprehension of the subject. The conclusion of this study partially differs from previous research as it finds support for both theories. However none of the theories are applicable on the Swedish market as a whole which suggests that further research is required along with the addition of new ideas. This paper is written in Swedish.
79

Le morphisme déterminant pour les espaces de modules de groupes p-divisibles / The determinant morphism for the moduli spaces of p-divisible groups

Chen, Miaofen 11 May 2011 (has links)
Soit \M un espace de modules de groupes p-divisibles introduit par Rapoport et Zink. Supposons que cet espace \M soit non-ramifié de type EL ou PEL unitaire ou symplectique. Soit \Mrig la fibre générique de Berthelot de \M. C'est un espace rigide analytique au-dessus duquel il existe une tour de revêtements étales finis (\M_K)_K qui classifient les structures de niveau. On définit un morphisme déterminant \det_K de la tour (\M_K)_K vers une tour d'espaces rigides analytiques étales de dimension 0 associée au cocentre du groupe réductif relié à cet espace. C'est un analogue local en des places non-archimédiennes du morphisme déterminant pour les variétés de Shimura défini par Deligne. Comme pour les variétés de Shimura, on montre que les fibres géométriques du morphisme déterminant \det_K sont les composantes connexes géométriques de \M_K. On définit aussi les morphismes puissances extérieures qui généralisent le morphisme déterminant sur la tour d'espaces rigides analytiques associée à un espace de Lubin-Tate. / Let \M be a moduli space of p-divisible groups introduced by Rapoport and Zink. Assume that \M is unramified of EL or PEL type which is unitary or symplectic. Let \Mrig be the generic fiber of Berthelot of \M. This is a rigid analytic space over which there exist a tower of finite etale coverings (\M_K)_K classifing the level structures. We define a determinant morphism \det_K from the tower (\M_K)_K to a tower of rigid analytic spaces of dimension 0 associated to the cocenter of the reductive group related to the space \M. This is a local analogue on the nonarchimedean places of the determinant morphism for Shimura varieties defined by Deligne. As for Shimura varieties, we prove that the geometric fibers of the determinant morphism \det_K are the geometrically connected components of \M_K. We define also the exterior power morphisms which generalize the determinant morphism on the tower of rigid analytic spaces associated to a Lubin-Tate space.
80

Epidemiologia da dengue na cidade de Rio Branco - Acre, Brasil, no período de 2000 a 2007 / Epidemiology of dengue in the city of Rio Branco- Acre, Brazil, from 2000 to 2007

Rocha, Ricardo da Costa 19 September 2011 (has links)
Objetivo Caracterizar a ocorrência de dengue na cidade de Rio Brando, estado do Acre, no período de 2000 a 2007, no tempo, no espaço e segundo infestação pelo Aedes aegypti e vari- áveis demográficas, socioeconômicas, ambientais e climáticas. Métodos Foi realizada uma descrição da incidência de dengue (CI) e da infestação predial pelo Aedes aegypti (IIP) no período de 2000 a 2007 a partir de dados secundários. Descreveu-se a incidência da dengue em relação ao sexo, faixa etária e escolaridade. O Coeficiente de Incidência e o Índice de In- festação Predial foram testados para aferição de correlações com variáveis climáticas, demo- gráficas, ambientais e socioeconômicas. Foi aplicada a técnica de geoprocessamento com o uso da estatística espacial de Moran Global e Local (LISA) para avaliar a autocorrelação es- pacial dos coeficientes de incidência de dengue entre as localidades urbanas da cidade. Resul- tados - A epidemiologia da dengue na cidade é caracterizada por elevada incidência e intensa infestação predial pelo Aedes aegypti. Não existe diferença na incidência de dengue entre ho- mens e mulheres e a faixa etária mais acometida compreende jovens e adultos de 15 a 49 anos e escolares que não concluíram o ensino médio. A distribuição da doença mostra um padrão sazonal com elevação da incidência nos períodos chuvosos e regressão nos períodos secos. O aumento de casos de dengue e da infestação predial mostrou associação significante (p<0,05) com bairros populosos, onde existe muitos imóveis e alta infestação predial. O aumento das ocorrências se mostrou significante com áreas com baixo índice de abastecimento de água pela rede pública. O Índice de Qualidade de Vida (IQV) não apresentou correlação significa- tiva com a ocorrência de dengue, entretanto, a infestação predial foi mais elevada nos bairros com melhor IQV. A estatística de Moran Global e Local (LISA) mostrou fraca dependência espacial (p<0,05) da incidência de dengue entre bairros da cidade. Conclusão - A análise epi- demiológica da dengue na cidade permitiu visualizar fatores que estão relacionados à trans- missão de dengue e na proliferação do Aedes aegypti que podem ser avaliados na formulação de estratégias mais eficazes para alcançar o melhor controle da doença. O uso da análise espa- cial evidenciou que a distribuição da incidência de dengue entre os bairros da cidade ocorre de maneira aleatória / Objective - Characterize the ocurring of dengue in the city of Rio Branco, Acre, during the period 2000 to 2007, in time and space, and according to the infestation of Aedes Aegypti and the demographic, social-economical, environmental and climatical variables. Methods - a description of dengue incidence (CI) and the house infestation by Aedes aegypti (HI) was made in the period of 2000 to 2007 from secondary data. The distribution of cases was described according to gender, age and education. The Incidence Coefficient of incidence and the House Index Infestation were tested to measure their correlations with demographic, environmental and socioeconomic climatic variables. The geoprocessing technique was applied with the use of Global and Local Moran (LISA) spatial statistics to evaluate spatial autocorrelation of incidence of dengue among the urban localities in the city. Results - The epidemiology of dengue in the city is characterized by high incidence and severe infestation of Aedes aegypti. Theres no difference between the incidence of dengue on men and women and the most affected age group comprises young adults from the age of 15 to 49 years old and students who have not completed high school. The distribution of the disease shows a seasonal pattern with increased incidence in rainy periods and regression in dry periods. The increase of dengue cases and the building infestation showed significant association (p <0.05) with the populated districts, where there are many buildings and high building infestation. The increase in occurrence was found significant in areas with low public water supply. The Quality of Life Index (QLI) showed no significant correlation with the occurrence of dengue, however, the infestation rate was higher in districts with better QLI. Global and Local Moran (LISA) statistics showed weak spatial dependence (p <0.05) of the incidence of dengue among neighborhoods. Conclusion - The epidemiological analysis of dengue in the city allowed the visualization of the factors that are related to the transmission of dengue and the proliferation of Aedes aegypti that can be assessed in the formulation of more effective strategies to achieve better control of the disease. The use of the spatial analysis revealed the randomness of dengue incidence distribution among the neighborhoods of the city

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