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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.
1

Bifocal lens control of myopia progression in children

Cheng, Desmond January 2008 (has links)
This research investigated underlying issues that were critical to the success of the bifocal trial and comprised of three studies. The first study evaluated if Chinese-Canadian children were suitable subjects for the bifocal trial. The high prevalence of myopia in Chinese children suggests that genetic input plays a role in myopia development, but the rapid increase in prevalence over the last few decades indicates environmental factors are also important. Since this bifocal trial was conducted in Canada, this work aimed to determine whether Chinese children who had migrated to Canada would still have high myopia prevalence and a high rate of myopia progression. The second study determined the optimal bifocal lens power for myopia treatment and the effect of incorporating base-in prism into the bifocal. In the majority of published myopia control studies, the power of the prescribed near addition was usually predetermined in the belief that the near addition would always help to improve the near focus. In fact, the effect of near addition on the accommodative error might be quite different even for individuals in which the same magnitude of accommodation lag had been measured. Therefore, this work was necessary to guide the selection of bifocal and prism powers most suitable for the subsequent bifocal trial. The third study, the ultimate goal of this research, was to conduct a longitudinal clinical trial to determine if bifocals and prismatic bifocals could control myopia progression in children.
2

Soft Multifocal Contact Lenses for Myopia Control in Children

Korsan, Jenna M. 22 May 2015 (has links)
No description available.
3

Toward unraveling the mystery of how the unusual principal eyes of Thermonectus marmoratus larvae work – constructing a first functional model.

Stowasser, Annette January 2013 (has links)
No description available.
4

VISUALIZAÇÃO HIERARQUICA APLICADA À METANÁLISE DA EFICIÊNCIA DO FUNGICIDA FLUQUINCONAZOL EM SEMENTES DE SOJA PARA O CONTROLE DA FERRUGEM ASIÁTICA

Delazeri, Bruna Rossetto 15 March 2015 (has links)
Made available in DSpace on 2017-07-21T14:19:28Z (GMT). No. of bitstreams: 1 Bruna Rossetto Delazeri.pdf: 4632056 bytes, checksum: 7b23d649c1cebd3b01425d6b2a960ae9 (MD5) Previous issue date: 2015-03-15 / Asian soybean rust caused by Phakopsora pachyrhizi, is one of the main phytosanitary problems of soybean in Brazil. Aiming to reduce the losses caused by the pathogen, the treatment of soybean seeds with fungicide fluquinconazole has motivated researchers to conduct studies and simulate their performance. The compilation of these various studies may be conducted by the meta-analysis, which is a probabilistic technique that produces a result which summarizes studies. In agricultural context, meta-analysis is used to perform empirical estimates of technical efficiency for the development of productivity and economic research of agriculture, such as the use of the fungicide fluquinconazole. Meta-analysis can be applied through existing software such as R, run through commands, and WMA, which operates through a graphical user interface for data entry made by the user. The results generated by both software are shown in graphical form without providing interactivity with the user, neither reproducing a friendly software and easy to understand interface. This study applied meta-analysis using the WMA Software, which uses R to calculate the statistical results, to determine the efficiency of fungicide fluquinconazole in soybean seed, used to minimize the impact of the asian rust disease in the crop productivity. To provide a dynamic display of obtained results by meta-analysis, this study created a method to identify the best information visualization technique to represent hierarchical data. This method was applied to identify which better visualization technique represented the graphic forest plot, namely, bifocal tree. Changes were made at the WMA, such as: incorporation of a new effect measure, change in the help system and font files and the implementation bifocal tree technique using Gephi as a support tool. The implementation allowed to create a more interactive environment for analyzing the results of the R and provides two display options for the user: basic and advanced. The advantages of the visualization are that the user can explore more the data and results. In this study it was observed that when fluquinconazole was used to minimize the effects caused by rust soybean productivity (yield) was improved. / A ferrugem asiática da soja, causada pelo fungo Phakopsora pachyrhizi, é um dos principais problemas fitossanitários da cultura da soja no Brasil. Visando diminuir os prejuízos causados pelo patógeno, o tratamento das sementes de soja com o fungicida fluquinconazol tem motivado pesquisadores a realizar estudos e simular seu desempenho. A compilação destes vários estudos pode ser realizada através da metanálise, que é uma técnica probabilística que produz um resultado que resume os estudos. No âmbito agrícola a metanálise é utilizada para realizar estimativas empíricas de eficiência para o desenvolvimento da produtividade e investigação econômica da agricultura, como é o caso do uso do fungicida fluquinconazol. A metanálise pode ser aplicada por meio de software existentes como por exemplo o R, executado através de comandos, e o WMA (Wizard Metanálise), que opera através de um interface gráfica para entrada de dados feita pelo usuário. Os resultados gerados por ambos são exibidos em forma gráfica sem proporcionar interatividade com o usuário, tampouco reproduzem uma interface amigável e de fácil compreensão. Este trabalho aplicou a metanálise através do WMA, que utiliza o R para o cálculo dos resultados estatísticos, para determinar a eficiência do fungicida fluquinconazol na semente da soja utilizada para minimizar o impacto causado pela doença da ferrugem asiática na produtividade da cultura. Para proporcionar uma visualização dinâmica dos resultados obtidos pela metanálise este trabalho criou um método de identificação da melhor técnica de visualização de informação para representar dados hierárquicos. Este método foi aplicado para identificar qual técnica de visualização melhor representava o gráfico forest plot, a saber, bifocal tree. Mudanças foram realizadas no WMA tais como: incorporação de uma nova medida de efeito, mudança no sistema de ajuda e dos arquivos fontes e adição da técnica bifocal tree usando como ferramenta de apoio o Gephi. A implementação permitiu criar um ambiente mais interativo para análise dos resultados obtidos pelo R e fornece duas opções de exibição para o usuário: básica e a avançada. As vantagens da visualização é que o usuário consegue explorar mais os dados e resultados. Neste trabalho observou-se que houve um ganho na taxa de produtividade da soja com a utilização do fluquinconazol, para minimizar os efeitos causados pela ferrugem.
5

Optimisation des optiques bifocales destinées à la correction de la presbytie / Optimization of bifocal optics used to compensate for presbyopia

Rio, David 16 September 2016 (has links)
Dans un contexte de vieillissement de la population, et donc d’augmentation du nombre de presbytes, l’amélioration des optiques destinées à la correction de ce défaut visuel est un enjeu crucial. Nous avons cherché à optimiser le design des optiques bifocales, qui ne présentent que deux puissances différentes: une pour la vision de loin et une pour la vision de près. Pour cela, nous avons simulé des images telles qu’elles seraient vues à travers nos designs, et les avons fait noter par des sujets. La première étude s’est penchée sur le ratio d’aire optimisant la vision au loin comme au près. Les meilleurs résultats ont été obtenus pour un ratio de 40% de vision de près au centre, même si des valeurs de 20 à 50% étaient satisfaisantes. Cependant, ces optiques à deux zones concentriques ont un défaut : elles sont très sensibles au changement de diamètre pupillaire, qui est très fréquent. Un changement de taille de pupille entrainant une modification du ratio d’aires, la solution consiste à utiliser plusieurs zones concentriques alternant entre correction de loin et de près. La seconde étude s’est focalisée sur l’optimisation du nombre de zones concentriques dans ces optiques bifocales par la même méthode. Lorsque le nombre de zones est augmenté suffisamment, des interférences permettent d’augmenter également la qualité de vision intermédiaire, nos profils étant disposés comme des réseaux de Fresnel. Les profils à 5 zones permettent une bonne vision de loin et de près en redonnant une légère vision intermédiaire, et les profils à 8 zones donnent une qualité de vision similaire au loin, en intermédiaire et au près. Ces profils ont ensuite été évalués dans des conditions plus réalistes, en présence d’aberrations, de décentrement, de différents diamètres pupillaires par deux populations d’âge différent. L’âge des sujets n’influence pas leur évaluation des optiques. Les aberrations ont plus d’impact sur la qualité visuelle que le décentrement. Le diamètre pupillaire a une influence plus forte sur les profils possédant moins de zones. Enfin, nous avons comparé nos profils optimisés avec des lentilles de contact disponibles sur le marché. Du point de vue de la qualité visuelle comme de la profondeur de champ, nos profils étaient meilleurs que les lentilles du marché. Il serait donc intéressant d’en créer des prototypes pour effectuer des tests au porté. Les designs développés dans cette thèse pourraient servir à effectuer une personnalisation de la correction optique des presbytes. Différents designs pourraient être proposés pour chaque oeil, permettant de combiner deux profils par sujets. De nombreuses variations inter-individuelles, également observées dans les études précédentes, restent toujours imprévisibles. Elles pourraient être dues à des différences de sensibilité au contraste ou de tolérance au flou. Il serait donc intéressant de développer un test optométrique, consistant à faire évaluer des images floues par le sujet, de façon à prédire s’il s’agit d’un bon candidat au port de lentilles bifocales. / Giving the aging of the population, and therefore the augmentation of presbyopes, the improvement of optics used to compensate for this visual impairment are at stake. We optimized bifocal optics designs, which only have two powers: one dedicated to distance vision and one dedicated to near vision. For this, we simulated images as they would appear through our designed optics, and asked subjects to grade the quality of these simulated images. First study dealt with the ratio of area optimizing visual quality at distance and at near. The best results were obtained for a ratio of 40% of central near vision, even if values from 20 to 50% gave quite comparable satisfying results. However, these 2 zone optics have a drawback they are very sensitive to the change of pupil diameter, which happens very often. A change in pupil size leads to a change of ratio of areas, the solution consists in using several concentric zones alternating between distance and near correction. The second study was about the optimization of the number of concentric zones in these bifocal optics using the same method. When the number of zones is increased enough, interferences allow to improve intermediate visual quality, as our profiles are built as Fresnel networks. Five zone profiles give a good distance and near vision with a little intermediate vision, and 8 zone profiles give an acceptable quality of vision from far to near. These profiles were evaluated in more realistic conditions, in presence of aberrations, decentration and different pupil diameters by two populations with different age. The age of subjects did not influence their evaluation of the optics. Aberrations had more impact on visual quality than decentration. Pupil diameter had a stronger influence on the optics with less number of zones. Eventually, we compared our optimized profiles with actual contact lenses available on the market. When looking at visual quality and depth-of-focus, our profiles were better than the ones available on the market. Therefore, it would be interesting to make prototypes to try them on real subjects. The designs developed in this work could be used to personalize presbyopes optical compensation. Different designs could be tried on each eye, allowing to combine two profiles per subject. A lot of inter-individual variations, also observed in previous studies, remain unpredictable. They could be linked to differences in contrast sensitivity or tolerance to blur. It would be interesting to create a visual test consisting in evaluating blurred images, in order to predict of a subject is a good candidate to fit with bifocal optics.
6

Quality of Life of Pediatric Bifocal Soft Contact Lens Wearers

Greiner, Katie Lynn 26 August 2009 (has links)
No description available.
7

Accommodative lag, peripheral aberrations, and myopia in children

Berntsen, David A. 01 September 2009 (has links)
No description available.
8

Messager sans message : traité de psychothérapie interculturelle / Messenger without a message : study on intercultural psychotherapy

Coyer, Gilbert 22 October 2009 (has links)
Cette recherche est issue d’une observation longitudinale de quatorze enfants suivis en psychothérapie ; reçus en consultations familiales avec des interprètes ou médiateurs ; soutenus dans leur environnement social et scolaire ; et pour certains, accueillis en hôpital de jour. Il s’agit essentiellement d’enfants d’origine africaine, simultanément engagés par leur famille dans des traitements traditionnels. Le caractère bifocal – individuel et environnemental – de ces suivis, ouvre à un questionnement épistémologique dans ces deux champs respectifs – psychologique et social – et dans celui de leur articulation. Il engage, pour éviter l’écueil du relativisme ou des confusions sémantiques, à un approfondissement des notions de complémentarisme et d’acculturation antagoniste telles qu’elles ont été formalisées par Devereux, et prolongées, pour cette dernière, par certains sociologues comme Bourdieu et Sayad, ou du point de vue des paradoxes qu’elle soulève, par les travaux de Winnicott, de Roussillon, de Bateson, ou de certains cognitivistes. Ces observations conjointes et longues, sur trois à dix ans, soulignent les nombreuses interfaces entre les problématiques des enfants suivis et le champ familial et social auquel ouvrent les traitements culturels de leur malaise. En cela, la réflexion sur ces psychothérapies interculturelles soutient celle déjà engagée par d’autres cliniciens sur l’articulation de l’intrasubjectivité et de l’intersubjectivité, et sur les médiations thérapeutiques. Elle amène à approfondir dans ce domaine le sens des notions de symbolisation, de traduction, et de transitionnalité, dans la suite des travaux de Roussillon, de Berman, et de Winnicott. / This work is based on the longitudinal observation of 14 children treated with psychotherapy, seen in family consultations with interpreters or mediators, supported in their social and school environment and in some cases, admitted to day hospitals. Most children are of African origin, with families that simultaneously looked for traditional treatments. The bifocal character of these follow-ups – individual and environmental – allows for epistemological questioning in both of the respective fields – psychological and social – and in their articulation. It involves, in order to avoid the pitfalls of relativism or semantic confusions, a more profound analysis of the notions of complementarism and antagonistic acculturation as they have been formalized by Devereux, and developed in the case of acculturation, by certain sociologists such as Bourdieu and Sayad, or from the perspective of paradoxes that result, of the work of Winnicott, Roussillon, Bateson and certain cognitivists. These conjoined and long clinical follow-ups lasting from three to ten years underline the numerous interfaces between the problematics of the treated children and the family and social fields implicit in the cultural treatment of their illness. As such, the reflection about these intercultural psychotherapies supports work already engaged by other clinicians on the articulation between intra- and inter-subjectivity and on therapeutic mediations. It allows for a more profound examination of meaning of the notions of symbolization, translation and transitional space, following the work of Roussillon, Berman and Winnicott.

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