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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.
21

Le rôle du chemin de fer en Afrique : les cas du Mozambique et du Kenya / The role of the railroad in Africa : case of Mozambique and Kenya

Béranger, Chantal 12 October 2012 (has links)
Cette thèse se situe dans l'articulation entre les thématiques du transport et du développement durable, par le biais du concept de congruence. Elle aborde plus spécifiquement la question du rôle du chemin de fer dans l'amélioration de la vie des populations rurales et particulièrement dans deux états africains, le Mozambique et le Kenya. / This thesis is the relationship between the themes of transport and sustainable development through the concept of congruence. It specifically addresses the issue of the role of the railway in improving the lives of rural populations and particularly in two African states, Mozambique and Kenya.
22

Exploring Pathways of Bullying Victimization: A Test of Two Competing Victimization Theories to Better Understand Risk of Bullying Experiences Among Middle School Youth

Stutzenberger, Amy L. 22 October 2020 (has links)
No description available.
23

Impact Of Cancer-specific Advance Care Planning On Anxiety, Decisional Conflict, And Surrogate Understanding Of Patient Treatment Preferences

Waser, Lynn 01 January 2012 (has links)
Patients with life-limiting cancer and their families face unique challenges that interfere with their ability to make decisions or adequately express their health care preferences about end of life (EOL) treatment. As a result, patients at EOL often receive aggressive unwanted treatment that nationally costs billions of dollars and results in surrogate distress about not honoring patient wishes. Respecting Choices® DS-ACP is a disease-specific Advance Care Planning (ACP) intervention that is designed to overcome barriers associated with ACP and potentially decrease the incidence of unwanted, overly aggressive treatments at EOL. The intervention is delivered to patient-surrogate dyads by a trained facilitator who provides an opportunity for patients to identify values and goals that support their EOL choices and communicate these values and goals to their surrogates before they are in a medical crisis. Although Respecting Choices® DS-ACP has been effective with other populations, it has not been evaluated for patients with life-limiting cancer. Thus, the purpose of this study was to evaluate the Respecting Choices® DS-ACP intervention with patients with life-limiting cancer to determine if the intervention increases patient-surrogate congruence about the patient's EOL wishes and reduces decisional conflict without causing anxiety. Study design was a Phase I clinical trial. A volunteer sample of 15 patients with a diagnosis of life limiting cancer and their matched surrogates participated in the study. The Statement of Treatment Preferences for Life-Limiting Cancer Form, the Spielberger Stateanxiety Scale Form Y-1 (STAI) and the Decisional Conflict Scale (DCS) were administered preand post-intervention. The Quality of Communication about End of Life Care Form was administered at post test. Descriptive statistics were used to describe the sample. McNemar Chisquare and Binomial tests were conducted to investigate whether the intervention increased iv congruence for five different situations on the Statement of Treatment Preferences for LifeLimiting Cancer Form. The Zar’s Multiple Comparison Test of Differences was conducted to investigate the proportion of congruence observed across the five situations. A paired-sample t test was conducted to evaluate post-intervention changes in anxiety (STAI) and decisional conflict (DCS). Frequencies and percentages were conducted for the five items on the Quality of Communication about End of Life Care Form to evaluate patients' and surrogates' satisfaction with the intervention. Anecdotal comments about timing were content analyzed and summarized. Congruence between patients and surrogates improved significantly in all five situations (range of p =.001 to .031), decisional conflict lessened significantly (t (14) =4.49, p < .001), and anxiety did not change (t (14) = 1.75, p = .102) pre- and post-intervention. Participants reported satisfaction with the intervention, including its delivery and timing. Findings from this study provide guidance on how to assist patients with life limiting cancer and their surrogates with EOL decision making. Study findings also support making the Respecting Choices ACP intervention part of usual care for patients with life limiting cancer and timing the intervention so that it is delivered before a medical crisis occurs. The lack of change in post-intervention anxiety scores suggests that ACP does not add to patient distress when ACP is conducted by a trained facilitator. This finding can be used to persuade health professionals to refer their patients for ACP. Additional research is needed to determine if increased patientsurrogate congruence leads to patients' wishes being followed and reduces surrogate decisional conflict and distress at EOL. Future research is also needed to determine if the Respecting Choices DS-ACP intervention is equally effective with racial and ethnic groups whose reluctance v to engage in EOL discussion has been documented in the literature or if the intervention needs to be culturally adapted.
24

Injectivity in Congruence Distributive Equational Classes

Day, Richard Alan 05 1900 (has links)
<p> In this thesis, we study the concept of injectivity in equational classes of (universal) algebras and in particular we are concerned with congruence distributive equational classes that have enough injectives. We show that every reasonable equationally complete congruence distributive equational class has enough injectives and we describe them completely. We then examine what equational subclasses of Lattices, Heyting algebras, and pseudo-complemented lattices have enough injectives.</p> / Thesis / Doctor of Philosophy (PhD)
25

Examining the Congruence between Couples' Perceived Infertility-Related Stress and its Relationship to Depression and Marital Adjustment in Infertile Men and Women

Peterson, Brennan Daniel 23 October 2000 (has links)
Recent studies have shown that the experience of infertility is linked with emotional responses such as depression, anxiety, guilt, social isolation, and decreased self-esteem in both men and women. This study explored the impact of congruence between couples' infertility-related stress and its effects on depression and marital adjustment in infertile men and women. Study participants were comprised of 525 couples referred to a university-affiliated teaching hospital for assessment and treatment with advanced reproductive technologies. Participants completed the Fertility Problem Inventory (FPI), the Beck Depression Inventory (BDI), and the Dyadic Adjustment Scale (DAS) three months prior to their first treatment cycle. The impact of differences between couples' perceptions of infertility-related stress were examined in relation to their effect on individual levels of depression and marital adjustment in both men and women. Results showed that differences between couple's evaluations of infertility-related stress were predictive of female depression, but not male depression. Women in couples who reported high levels of congruence (e.g., agreement) concerning the impact of infertility-related stress had significantly lower levels of depression when compared to couples in which females experienced a greater amount of stress than their partners. In terms of marital adjustment, men and women in couples who reported high levels of congruence concerning the impact of infertility-related stress reported significantly higher levels of adjustment when compared to couples who differed in their appraisals of the stress. Treatment implications based on these findings and future research directions are discussed. / Master of Science
26

Formalizing and Implementing a Reflexive Tactic for Automated Deduction in Coq / Formalisation et developpement d'une tactique reflexive pour la demonstration automatique en coq

Lescuyer, Stephane 04 January 2011 (has links)
Dans cette thèse, nous proposons une amélioration de l'automatisation des preuves dans l'assistant de preuve Coq. Cette automatisation est obtenue en intégrant à Coq les procédures de décision pour la logique propositionnelle, l'égalité et l'arithmétique linéaire constituant le noyau du solveur SMT Alt-Ergo. Cette intégration est réalisée en utilisant la technique de preuve par réflexion, qui consiste à développer en Coq ces algorithmes et à prouver formellement leur correction de manière à les exécuter directement dans l'assistant de preuve. Comme les algorithmes formalisés en Coq sont exactement ceux utilisés dans le noyau d'Alt-Ergo, notre travail permet également d'augmenter considérablement la confiance que l'on peut avoir dans ce dernier. En particulier, il utilise un algorithme original de combinaison de l'égalité modulo une théorie, inspiré de la combinaison de Shostak et appelé CC(X), et dont la justification est relativement complexe.Notre développement Coq est utilisable sous la forme de tactiques qui permettent de valider automatiquement des formules combinant logique propositionnelle, égalité et arithmétique. Afin que ces tactiques soient le plus efficaces possibles, nous avons attaché une grande importance aux performances de notre implantation Coq, et en particulier à l'utilisation de structures de données efficaces courantes, dont nous proposons ici une bibliothèque. / In this thesis, we propose new automation capabilities for the Coq proof assistant. We obtain this mechanization via an integration into Coq of decision procedures for propositional logic, equality reasoning and linear arithmetic which make up the core of the Alt-Ergo SMT solver. This integration is achieved through the reflection technique, which consists in implementing and formally proving these algorithms in Coq in order to execute them directly in the proof assistant. Because the algorithms formalized in Coq are exactly those in use in Alt-Ergo's kernel, this work significantly increases our trust in the solver. In particular, it embeds an original algorithm for combining equality modulo theory reasoning, called CC(X) and inspired by the Shostak combination algorithm, and whose justification is quite complex. Our Coq implementation is available in the form of tactics which allow one to automatically solve formulae combining propositional logic, equality and arithmetic. In order to make these tactics as efficient as may be, we have taken special care with performance in our implementation, in particular through the use of classical efficient data structures, which we provide as a separate library.
27

Residually small varieties and commutator theory.

Swart, Istine Rodseth. January 2000 (has links)
Chapter 0 In this introductory chapter, certain notational and terminological conventions are established and a summary given of background results that are needed in subsequent chapters. Chapter 1 In this chapter, the notion of a "weak conguence formula" [Tay72], [BB75] is introduced and used to characterize both subdirectly irreducible algebras and essential extensions. Special attention is paid to the role they play in varieties with definable principal congruences. The chapter focuses on residually small varieties; several of its results take their motivation from the so-called "Quackenbush Problem" and the "RS Conjecture". One of the main results presented gives nine equivalent characterizations of a residually small variety; it is largely due to W. Taylor. It is followed by several illustrative examples of residually small varieties. The connections between residual smallness and several other (mostly categorical) properties are also considered, e.g., absolute retracts, injectivity, congruence extensibility, transferability of injections and the existence of injective hulls. A result of Taylor that establishes a bound on the size of an injective hull is included. Chapter 2 Beginning with a proof of A. Day's Mal'cev-style characterization of congruence modular varieties [Day69] (incorporating H.-P. Gumm's "Shifting Lemma"), this chapter is a self-contained development of commutator theory in such varieties. We adopt the purely algebraic approach of R. Freese and R. McKenzie [FM87] but show that, in modular varieties, their notion of the commutator [α,β] of two congruences α and β of an algebra coincides with that introduced earlier by J. Hagemann and C. Herrmann [HH79] as well as with the geometric approach proposed by Gumm [Gum80a],[Gum83]. Basic properties of the commutator are established, such as that it behaves very well with respect to homomorphisms and sufficiently well in products and subalgebras. Various characterizations of the condition "(x, y) Є [α,β]” are proved. These results will be applied in the following chapters. We show how the theory manifests itself in groups (where it gives the familiar group theoretic commutator), rings, modules and congruence distributive varieties. Chapter 3 We define Abelian congruences, and Abelian and affine algebras. Abelian algebras are algebras A in which [A2, A2] = idA (where A2 and idA are the greatest and least congruences of A). We show that an affine algebra is polynomially equivalent to a module over a ring (and is Abelian). We give a proof that an Abelian algebra in a modular variety is affine; this is Herrmann's Funda- mental Theorem of Abelian Algebras [Her79]. Herrmann and Gumm [Gum78], [Gum80a] established that any modular variety has a so-called ternary "difference term" (a key ingredient of the Fundamental Theorem's proof). We derive some properties of such a term, the most significant being that its existence characterizes modular varieties. Chapter 4 An important result in this chapter (which is due to several authors) is the description of subdirectly irreducible algebras in a congruence modular variety. In the case of congruence distributive varieties, this theorem specializes to Jόnsson's Theorem. We consider some properties of a commutator identity (Cl) which is a necessary condition for a modular variety to be residually small. In the main result of the chapter we see that for a finite algebra A in a modular variety, the variety V(A) is residually small if and only if the subalgebras of A satisfy (Cl). This theorem of Freese and McKenzie also proves that a finitely generated congruence modular residually small variety has a finite residual bound, and it describes such a bound. Thus, within modular varieties, it proves the RS Conjecture. Conclusion The conclusion is a brief survey of further important results about residually small varieties, and includes mention of the recently disproved (general) RS Conjecture. / Thesis (M.Sc.)-University of Natal, Durban, 2000.
28

Fonctorialité, idéaux de congruence et grandes images de représentations galoisiennes associées aux familles de Hida / Functoriality, congruence ideals and big image of Galois representations associated to Hida families

Chen, Huan 15 September 2017 (has links)
Hida a étudié l'image de la représentation galoisienne associée à une famille p-adique de Hida de formes automorphes. Il a montré que l'image d'une famille non CM de formes modulaires classiques ordinaires contient un sous-groupe de congruence. Il a aussi lié le niveau optimal du groupe de congruence à l'idéal de congruence entre la famille de Hida non-CM et des familles CM. Cette thèse se divise en deux parties. La première partie est à généraliser ce genre de résultats dans le cas ordinaire pour les familles de Hida sur les groupes réductifs sous les hypothèses techniques. La deuxième partie se consacre à étudier les cas concrets. On montre que les hypothèses techniques sont satisfaites. Donc le même type de résultats est établi automatiquement. / Hida has studied the image of Galois representation associated to a p-adic Hida family of automorphic forms. He has proved that the image of a non-CM family ofordinary classic modular forms contains a congruence subgroup. He also related the optimal level of congruence subgroup to the congruence ideal between the non-CM Hida family and the CM ones. This thesis is divided into two parts. In the first part,we generalize this type of results to ordinary Hida families over reductive groups under some technical hypothesis. In the second part, we consider concrete cases. We prove that the technical hypothesis are satised for these cases. Hence the same type of results is established automatically.
29

L’influence de la stimulation tactile lors de l’évaluation en ligne du produit / The influence of tactile stimulation in online product evaluation

Racat, Margot 21 November 2016 (has links)
Ce travail de recherche doctorale étudie l’influence de la stimulation tactile de l’interface lors de l’évaluation en ligne du produit. A travers un plan d’expériences composé d’une étude exploratoire au design de recherche mixte et de trois expérimentations, nous cherchons à identifier, dans un premier temps, l’effet de l’absence d’interaction directe avec le produit (étude exploratoire) puis nous testons l’effet du type de test de produits sur la préférence d’achat du consommateur (i.e. physique vs. virtuel) (étude 1). Dans un deuxième temps, nous étudions l’effet de la stimulation tactile directe de l’interface sur la perception de similarité du test et l’influence de cette dernière sur l’évaluation du produit. En particulier, nous testons deux effets: celui de la congruence entre la stimulation tactile de l’interface et la texture du produit (étude 2) puis celui de la familiarité des textures (étude 3). D’une part, nous montrons que le consommateur est à la recherche d’interaction sensorielle lors de son interaction virtuelle avec les produits, ce qui lui permet de considérer cette expérience virtuelle comme plus réaliste, notamment au niveau sensoriel (étude exploratoire). Nous montrons également que le consommateur préfère l’expérience virtuelle du produit malgré le manque significatif d’interactions sensorielles, notamment tactiles (étude 1). D’autre part, nous montrons que l’interaction des textures entre l’interface et le produit influence négativement la similarité perçue du test (étude 2) tandis que, lorsque les textures ne sont pas familières, l’interaction des textures influence positivement la similarité perçue (étude 3). A partir de ces résultats, nous concluons que le consommateur est à la recherche de stimulation tactile lors de son expérience virtuelle avec le produit afin de satisfaire son besoin de toucher et d’enrichir son expérience sensorielle en ligne. En particulier, l’effet positif de l’interaction des textures, lorsque la stimulation n’est pas familière, sur la similarité perçue du test suggère que les consommateurs considèrent l’information tactile comme suffisante pour percevoir une similarité sensorielle à celle obtenue en magasin. / Our doctoral research examines the influence of tactile stimulation in online product evaluation. With an exploratory study and three experiments, we aim at identifying the effect of the absence of direct product touch (exploratory study), and then concentrate on the effect of the type of product testing on the consumer’s preference for purchasing (physical vs. virtual) (study 1). Next, we look at the influence of the interface tactile stimulation on the perceived product test similarity, of which the latter positively influences the online product evaluation. In particular, we test two types of effect: the congruence (study 2) and the familiarity of the textures (study 3). On the one hand, our results show that consumers are seeking a higher sensory input into online environments while interacting with products, especially from a tactile perspective (exploratory study). Results also highlight that consumers prefer the online product experience, even though they regret the absence of products' tactile sensations (study 1). On the other hand, we demonstrate that the interaction between the interface's direct tactile stimulation and the product's texture negatively influence the perceived similarity of product testing when textures fit, whereas when the textures are unfamiliar, the interaction of texture positively influences the perceived similarity of product testing. From these results, we conclude that consumers are in need of tactile input into virtual product experiences to satisfy their need for touch, and enhance their online sensory experiences. Notably, the positive effect of the interaction of textures, in an unfamiliar tactile stimulation, suggests that consumers consider the direct tactile stimulation as not being sufficient enough to provide useful information, but they assimilate it to a real product testing from a tactile perspective.
30

Sobre a teoria das transformações de superfícies de curvatura constante / About the theory on transformations of surfaces with constant curvature

Sander, Gabriela Pereira 22 May 2009 (has links)
A teoria das transforma»ções de superfícies de curvatura constante começou, no fim do século XIX, com o trabalho [3] de A.V. Bäcklund e, em seguida, recebeu importantes contribuições por parte de diversos geômetras, entre eles, L. Bianchi e C. Guichard (veja, por exemplo, [5, 6, 7, 17]). Nessa dissertação apresentamos alguns dos mais importantes resultados desse tópico da geometria diferencial que estão relacionados às superfícies de curvatura média (ou gaussiana não nula) constante. Tais superfícies estão associadas a soluções de equações diferenciais parciais de segunda ordem e não lineares. A interpretação analítica da teoria das transformações de superfícies de curvatura constante nos capacita obter soluções dessas equações diferenciais parciais a partir de uma outra dada, mediante integração de um sistema de equações diferenciais, chamado transformação de Bäcklund. Então, os teoremas de permutabilidade fornecem uma \"fórmula de superposição\" para a construção algébrica de novas soluções / The theory on transformations of surfaces with constant curvature begins, in the late nineteen century, with the article [3] of A.V. Bäcklund and, after, received important contributions from various geometricians, among others, L. Bianchi and C. Guichard (see, for example, [5, 6, 7, 17]). In this dissertation we outline some of the most important results on the theory of surfaces of constant mean (or gaussian) curvature. Such surfaces are associated to the solutions of nonlinear partial differential equations of second order. The analytic interpretation of the theory on transformations of constant curvature surfaces provides a method of obtaining, from a given solution of these partial differential equations, a new solution of the same equation, by integrating a system of differential equations, called Bäcklund transformation. Then, the permutability theorems give a \"superposition formula\" to construct, algebraically, new solutions

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