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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.
111

Plantar Measurements to Determine Success of Surgical Correction of Stage IIb Adult Acquired Flatfoot Deformity

Matheis, Erika 14 December 2012 (has links)
Adult Acquired Flatfoot Deformity (AAFD) is a progressive disease characterized by mechanical degeneration of the soft tissue structure in the arch of the foot that leads to changes in joint alignment. Surgical intervention commonly via tendon transfer and bony osteotomy is used to restore arch architecture, however there is a lack of quantitative assessments that measure the success of the surgical correction in vivo. Using plantar pressures via Tekscan® HR Mat and surveys (SF-36, FAOS), pre-operative and post-operative measures for six participants were defined, analyzed and compared. A paired t-test showed significant lateral shift for percent body weight during walking postoperativelyin the forefoot and midfoot regions. However, arch index measurement showed no significant change. The FAOS survey score also improved statistically postoperatively. The surgical correction was successful as deemed by some of these quantitative and qualitative measures.
112

Bayesovské přístupy ve stochastickém rezervování / Bayesian Approaches to Stochastic Reserving

Novotová, Simona January 2014 (has links)
In the master thesis the issue of bayesian approach to stochastic reserving is solved. Reserving problem is very discussed in insurance industry. The text introduces the basic actuarial notation and terminology and explains the bayesian inference in statistics and estimation. The main part of the thesis is framed by the description of the particular bayesian models. It is focused on the derivation of estimators for the reserves and ultimate claims. The aim of the thesis is to show the practical uses of the models and the relations between them. For this purpose the methods are applied on a real data set. Obtained results are summarized in tables and the comparison of the methods is provided. Finally the impact of a prior distribution on the resulting reserves is showed. Powered by TCPDF (www.tcpdf.org)
113

Contribution of the canonical Wnt pathway in Tribolium anterior-posterior axis patterning

Fu, Jinping January 1900 (has links)
Doctor of Philosophy / Department of Biology / Susan J. Brown / How animals polarize and establish the main axis during embryogenesis has been one of the most attractive questions in Biology. Increasing body of work in various model organisms implicates that most metazoans utilize the canonical Wnt signaling pathway to pattern the anterior-posterior (AP) axis, despite the limited evidence from arthropods. In Drosophila, a highly derived insect, canonical Wnt activity is not required for global AP patterning, but in typical insects including Tribolium castaneum, loss of canonical Wnt activity results in posterior truncation. To determine the eff ects of increased canonical Wnt levels, I analyzed the function of axin, encoding a highly conserved negative regulator of the pathway. Tc-axin transcripts are maternally localized to the anterior pole in freshly laid eggs. Parental RNAi for Tc-axin produced progeny phenotypes that ranged from mildly a ffected embryos with cuticles displaying a graded loss of anterior structures, to severely a ffected embryos lacking cuticles and condensing to the posterior pole of the egg without any de finable structures. Altered expression patterns of several blastodermal markers indicated anterior expansion of posterior fates. Epistasis analysis of other canonical Wnt pathway components and the expansion of Tc-caudal expression, a Wnt target, suggest that the eff ects of Tc-axin depletion are mediated through this pathway and that canonical Wnt activity must be repressed for proper anterior development in Tribolium. These studies provide unique evidence that canonical Wnt activity must be carefully regulated along the AP axis in an arthropod, and support an ancestral role for Wnt signaling in de fining AP polarity and patterning in metazoan development. Additionally, as an anterior structure, the extraembryonic serosa is reduced in Tc-axin RNAi progeny. However, in Tc-pangolin (Tc-pan, a homolog of Wnt downstream component) RNAi progeny, an interesting phenotype was produced that serosa was not only reduced but also separated into distinct anterior and dorsal domains. I carefully recorded this phenomenon with live imaging using a Tribolium transgenic line that expresses GFP in each nucleus. Through careful examination with embryonic fate-map markers, I found that the tissue between separated serosa domains is dorsally extended head lobe. And I also found that in severe phenotype, dorsal serosa was completely gone while anterior serosa not, suggesting independent regulation mechanisms for anterior and dorsal serosa formation. This descriptive data will complement future study in the genetic mechanism underlying serosa formation by providing more details in morphogenesis.
114

Classification de bases de données déséquilibrées par des règles de décomposition / Handling imbalanced datasets by reconstruction rules in decomposition schemes

D'Ambrosio, Roberto 07 March 2014 (has links)
Le déséquilibre entre la distribution des a priori est rencontré dans un nombre très large de domaines. Les algorithmes d’apprentissage conventionnels sont moins efficaces dans la prévision d’échantillons appartenant aux classes minoritaires. Notre but est de développer une règle de reconstruction adaptée aux catégories de données biaisées. Nous proposons une nouvelle règle, la Reconstruction Rule par sélection, qui, dans le schéma ‘One-per-Class’, utilise la fiabilité, des étiquettes et des distributions a priori pour permettre de calculer une décision finale. Les tests démontrent que la performance du système s’améliore en utilisant cette règle plutôt que des règles classiques. Nous étudions également les règles dans l’ ‘Error Correcting Output Code’ (ECOC) décomposition. Inspiré par une règle de reconstitution de données statistiques conçue pour le ‘One-per-Class’ et ‘Pair-Wise Coupling’ des approches sur la décomposition, nous avons développé une règle qui s’applique à la régression ‘softmax’ sur la fiabilité afin d’évaluer la classification finale. Les résultats montrent que ce choix améliore les performances avec respect de la règle statistique existante et des règles de reconstructions classiques. Sur ce thème d’estimation fiable nous remarquons que peu de travaux ont porté sur l’efficacité de l’estimation postérieure dans le cadre de boosting. Suivant ce raisonnement, nous développons une estimation postérieure efficace en boosting Nearest Neighbors. Utilisant Universal Nearest Neighbours classification nous prouvons qu’il existe une sous-catégorie de fonctions, dont la minimisation apporte statistiquement de simples et efficaces estimateurs de Bayes postérieurs. / Disproportion among class priors is encountered in a large number of domains making conventional learning algorithms less effective in predicting samples belonging to the minority classes. We aim at developing a reconstruction rule suited to multiclass skewed data. In performing this task we use the classification reliability that conveys useful information on the goodness of classification acts. In the framework of One-per-Class decomposition scheme we design a novel reconstruction rule, Reconstruction Rule by Selection, which uses classifiers reliabilities, crisp labels and a-priori distributions to compute the final decision. Tests show that system performance improves using this rule rather than using well-established reconstruction rules. We investigate also the rules in the Error Correcting Output Code (ECOC) decomposition framework. Inspired by a statistical reconstruction rule designed for the One-per-Class and Pair-Wise Coupling decomposition approaches, we have developed a rule that applies softmax regression on reliability outputs in order to estimate the final classification. Results show that this choice improves the performances with respect to the existing statistical rule and to well-established reconstruction rules. On the topic of reliability estimation we notice that small attention has been given to efficient posteriors estimation in the boosting framework. On this reason we develop an efficient posteriors estimator by boosting Nearest Neighbors. Using Universal Nearest Neighbours classifier we prove that a sub-class of surrogate losses exists, whose minimization brings simple and statistically efficient estimators for Bayes posteriors.
115

Discrete Parameter Estimation for Rare Events: From Binomial to Extreme Value Distributions

Schneider, Laura Fee 26 April 2019 (has links)
No description available.
116

Estudo comparativo entre dois métodos de tratamento da lesão do ligamento cruzado posterior por avulsão óssea na tíbia : amarrilho artroscópico e fixação com parafuso por via posterior aberta / Comparative study between two methods of treatment of tibial posterior cruciate ligament bony avulsion: arthroscopic suture and screw fixation using open posterior approach.

Sasaki, Sandra Umeda 15 December 2003 (has links)
Atualmente, os bons resultados na lesão do ligamento cruzado posterior por avulsão óssea na tíbia associam-se ao tratamento cirúrgico e precoce. A técnica convencional é a fixação com parafuso pela via de acesso posterior do joelho, com abordagem direta das estruturas vasculares e nervosas da região. Neste estudo experimental em 20 joelhos de cadáveres, buscamos apresentar uma alternativa com amarrilho por via artroscópica, comparando-o com a técnica convencional, através da inspeção direta e de testes biomecânicos. Houve falha na fixação de apenas um exemplar de cada método e medidas de deslocamento tibial posterior (p=0,23) e rigidez média (p=0,28) sem diferenças significativas entre as duas técnicas. Concluímos ser o amarrilho artroscópico viável e uma alternativa no tratamento desta lesão. / Nowadays, good results on the management of posterior cruciate ligament bony avulsion of the tibia are associated with early surgical repair. The usual method of treatment is the open posterior approach with screw fixation, wich requires popliteal neurovascular bundle direct manipulation. This study presents a new arthroscopic suture and compares it with the conventional technique, using biomechanical tests and direct inspection in cadaveric specimens (20 knees). On both methods there was a fixation fail in one knee. The analisys of tibial posterior displacement (p=0,23) and stiffness (p=0,20) were similar for the two methods. The Arthroscopic suture presented is an effective reattachment method for this fracture pattern.
117

Reabilitação vestibular da vertigem postural paroxística benigna de canal posterior em idosos / Vestibular rehabilitation of benign posterior canal postural vertigo in the aged

André, Ana Paula do Rego 15 December 2003 (has links)
A Reabilitação Vestibular (RV) é um programa de tratamento realizado por exercícios, associado a um conjunto de medidas relacionadas à mudança de hábitos e esclarecimentos sobre os sintomas associados à alteração do equilíbrio. É um método de terapia fisiológico, inócuo e coerente, que pretende trabalhar o paciente vertiginoso aliviando os sintomas e aumentando seu limiar de sensibilidade para a vertigem. A Vertigem Postural Paroxística Benigna (VPPB) é a mais comum das vestibulopatias periféricas em adultos, principalmente em idosos do sexo feminino, apresentando como etiologia mais comum a degeneração da mácula utricular. Nos idosos, caracteriza-se por tontura rotatória e nistagmo posicional à mudança de posição da cabeça ou por determinada posição do corpo e, como conseqüência, pode ocorrer quedas e limitações na qualidade de vida dos mesmos, tornando-os limitados físico e emocionalmente. O presente estudo teve como objetivo avaliar prospetivamente a Reabilitação Vestibular como tratamento da VPPB com acometimento de canal semicircular posterior e seu efeito na qualidade de vida em indivíduos idosos. Participaram do estudo 23 voluntários com hipótese diagnóstica otorrinolaringológica de VPPB de canal semicircular posterior por ductolitíase, com faixa etária entre 60 e 91 anos, com média de 70,69 anos e desvio padrão de 9,24. Quanto ao gênero 17 (73,9%) eram do sexo feminino e 6 (26,1%) do masculino. No tratamento da VPPB por meio da reabilitação vestibular em 17 (73,9%) dos voluntários, utilizou-se a manobra de Epley; 6 (26,08%) com manobra de Epley associada ao exercício de Brandt e Daroff . O tempo de tratamento variou de 2 a 6 semanas. Aplicou-se um questionário (Dizziness Handicap Inventory - DHI brasileiro) pré e pós RV para quantificar a tontura quanto aos aspectos: físico, emocional, funcional e geral. Quanto ao aspecto físico, emocional, funcional e geral observou-se diferença estatisticamente significativa (p<0,0001) entre os escores pré e pós RV. Concluímos que os escores dos aspectos avaliados no DHI brasileiro melhoraram após intervenção fonoaudiológica pela RV nos pacientes com VPPB de canal semicircular posterior, havendo um incremento na qualidade de vida dos voluntários estudados. / Vestibular rehabilitation is a treatment?s program based on exercises, associated with a factor?s collection related to changing habits and guidance about symptoms associates to unbalance. It is harmless, coherent and physiologic therapy method that intends to work the dizzy patient, relieving the symptoms and increasing his vertigo?s threshold. The Benign Paroxysmal Positional Vertigo is the one most frequent adult?s pathologies of the peripheral vestibular?s system. It is caused by the utricle?s degeneration. In aged people, is characterize by vertigo and positional nystagmus provoked by certain cephalic movements or body movements and, as sequelae, can take to falls and life quality restriction, physical and emotional. This study?s purpose was evaluate the Vestibular Rehabilitation in posterior canal?s BPPV?s treatment and its effect in the elderly life?s quality. Twenty three volunteers with BPPV ?s posterior canal?s canalith diagnoses pointed out by otorhinolaryngologist, aged between sixty to ninety one years old, average of 70,69 years and deviation of 9,24. Seventeen volunteers (73,9%) were female and six (26,1%) were male. In BPPV?s treatment by vestibular rehabilitation, thirteen (56,52%) were submitted to Epley maneuver, six (26,08%) used the Epley maneuver associated to Brandt- Daroff exercises and four patients (17,39%) were submitted only to the Brandt- Daroff exercises. The treatment?s time lasted from 2 to 6 weeks. A questionnaire (Dizziness Handicap Inventory Portuguese- DHI Portuguese) was used in order to dizziness quantity in the physical, emotional, functional and general aspects, which was observed a significant statistical difference (p<0,001) between the scores previous and after Vestibular Rehabilitation. Concluding that the aspects? scores evaluated improved after Vestibular Rehabilitation therapy in the posterior canal?s BPPV?s patients, occurring an improvement in volunteers? life quality.
118

Bayesian Nonparametric Models for Multi-Stage Sample Surveys

Yin, Jiani 27 April 2016 (has links)
It is a standard practice in small area estimation (SAE) to use a model-based approach to borrow information from neighboring areas or from areas with similar characteristics. However, survey data tend to have gaps, ties and outliers, and parametric models may be problematic because statistical inference is sensitive to parametric assumptions. We propose nonparametric hierarchical Bayesian models for multi-stage finite population sampling to robustify the inference and allow for heterogeneity, outliers, skewness, etc. Bayesian predictive inference for SAE is studied by embedding a parametric model in a nonparametric model. The Dirichlet process (DP) has attractive properties such as clustering that permits borrowing information. We exemplify by considering in detail two-stage and three-stage hierarchical Bayesian models with DPs at various stages. The computational difficulties of the predictive inference when the population size is much larger than the sample size can be overcome by the stick-breaking algorithm and approximate methods. Moreover, the model comparison is conducted by computing log pseudo marginal likelihood and Bayes factors. We illustrate the methodology using body mass index (BMI) data from the National Health and Nutrition Examination Survey and simulated data. We conclude that a nonparametric model should be used unless there is a strong belief in the specific parametric form of a model.
119

Descrição morfológica do intestino posterior e comportamento diferencial do reto de Bombyx mori frente ao AlfaBV

Silva, Sóstenez Alexandre Vessaro da 17 October 2013 (has links)
Made available in DSpace on 2017-07-10T14:17:03Z (GMT). No. of bitstreams: 1 sostenez.pdf: 5444547 bytes, checksum: 0e57c73e9d81ba62bd8cce82698d43f6 (MD5) Previous issue date: 2013-10-17 / Bombyx mori nucleopolyhedrovirus (BmNPV) is an entomopathogenic and poliorganotrophic virus that infects Bombyx mori. BmNPV consists of a double strand DNA with two distinct phenotypes: the derived polyhedral virus (PDV), responsible for the primary infection in the insect s midgut; and the budded virus (BV), which disperses the infection in the hemocele, causing secondary or systemic infection. It is extremely virulent and when it infects silkworms, causes serious damages to the insect, usually leading to its death or harming the silk production, affecting all the productive chain, leading to economic losses. For a good silk production, a determinant factor is the functioning of the food duct, which is divided in foregut, midgut and hindgut, being the hindgut the place for water and mineral salts absorption and for the end of the digestive process. Several tissues have been established as virus targets, however, others have shown to be resilient to BmNPV. Given the importance of the hindgut, the present paper aimed to verify the susceptibility of its components, ileum, colon and rectum to an geographic isolated of BmNPV in Paraná, Brasil, the BmMNPV. In different post-inoculation days (dpi), the hindgut segment of 5th instar silkworms was dissected and processed for analysis in light microscopy, using conventional dyes and cytochemistry for viral detection and electronic scanning microscopy for the morphological details. The results revealed that the ileum, colon and rectum of the B. mori are constituted by simple epithelium, with alterations in cell morphology, covered by an intima in its luminal side, and that its organization is similar to that of other described insects. The cytological analysis of the ileum, colon and fore rectum revealed that its epithelial cells are not susceptible to BmMNPV in neither of the times analyzed. However, the posterior hindgut or anal duct showed itself to be susceptible to the virus after the 5º dpi, developing all the classic signs described for the infection with AlphaBV, as the presence of viroplasm, nuclear hypertrophy, polyhedra in formation and mature ones. At the end of the infectious cycle, occurs cell lysis with the liberation of viral polyhedra in the intestinal lumen and, consequently, to the external medium, coinciding with the death of the insect. Even with no infection in the other regions of the hindgut, the surrounding tissues have shown infected, affecting the normal functioning of this intestinal region, verified through changes in fecal pellet, which was less compact and changed format. These results will contribute in the establishment of the BmMNPV infectious cycle. Furthermore, the basic knowledge of viral behavior is important for the development of infection control, prevention and previous identification methods of this disease in the field, once it also makes possible the removal of infected silkworms, diminishing the horizontal transmission of the virus in the creation rooms, in a way to reduce the loss of cocoons to be used in the confection of silk yarn / Bombyx mori nucleopolyhedrovirus multiple (BmMNPV) é um vírus entomopatogênico e poliorganotrófico, constituído por DNA fita dupla e apresenta dois fenótipos distintos: o vírus poliédrico derivado, responsável pela infecção primária no intestino médio do inseto; e o vírus broto, que se dispersa na hemocele causando a infecção secundária ou sistêmica. É extremamente virulento e quando infecta lagartas do bicho-da-seda, causa sérios danos ao inseto, geralmente levando-o à morte ou prejudicando a produção da seda, comprometendo toda a sua cadeia produtiva e gerando prejuízos econômicos. Para uma boa produção de seda, um fator determinante é o funcionamento do canal alimentar, que nos insetos é dividido em anterior, médio e posterior, sendo o posterior, local de absorção de água e sais minerais e da finalização do processo digestório. Vários tecidos já foram estabelecidos como alvos do BmMNPV, entretanto outros se mostraram resistentes. Dada a importância do intestino posterior, o presente trabalho objetivou verificar a susceptibilidade de seus componentes, íleo, cólon e reto de lagartas de B. mori do 5° instar ao BmMNPV isolado geográfico do Paraná. Em diferentes dias pós-inoculação (dpi), o intestino posterior foi dissecado e processado para análise em microscopia de luz, utilizando colorações convencionais e citoquímica para detecção viral, e microscopia eletrônica de varredura, para os detalhes morfológicos. Os resultados revelaram que o íleo, cólon e reto de B. mori apresentou morfologia semelhante a de outros lepidópteros. A análise citopatológica do íleo, cólon e o reto anterior revelou que suas células epiteliais não são susceptíveis ao BmMNPV, em nenhum dos tempos analisados. Já o reto posterior ou canal anal, mostrou-se susceptível ao vírus a partir do 5º dpi, desenvolvendo todos os sinais clássicos descritos para a infecção com o AlphaBV, como presença de viroplasma, hipertrofia nuclear, poliedros em formação e maduros. No final do ciclo infeccioso, ocorre a lise celular com a liberação dos poliedros virais para luz intestinal e, consequentemente, para o meio externo, coincidindo com a morte do inseto. Mesmo não havendo infecção nas demais regiões do intestino posterior, os tecidos circunvizinhos se mostraram infectados, o que possivelmente afetou o funcionamento normal desta região, sendo visíveis as modificações na formação do pellet fecal, que se mostrou menos compacto e com alterações no formato. Os resultados obtidos irão contribuir no estabelecimento do ciclo infeccioso deste patógeno. Além disso, o conhecimento básico do comportamento viral é importante para o desenvolvimento de métodos de controle da infecção, prevenção e identificação prévia desta doença no campo, pois, possibilita ainda, a retirada de lagartas infectadas, diminuindo a transmissão horizontal do vírus nos barracões de criação, de forma a reduzir a perda de casulos, a serem utilizados na confecção dos fios de seda
120

Fast Inference for Interactive Models of Text

Lund, Jeffrey A 01 September 2015 (has links)
Probabilistic models of text are a useful tool for enabling the analysis of large collections of digital text. For example, Latent Dirichlet Allocation can quickly produce topical summaries of large collections of text documents. Many important uses cases of such models include human interaction during the inference process for these models of text. For example, the Interactive Topic Model extends Latent Dirichlet Allocation to incorporate human expertiese during inference in order to produce topics which are better suited to individual user needs. However, interactive use cases of probabalistic models of text introduce new constraints on inference - the inference procedure must not only be accurate, but also fast enough to facilitate human interaction. If the inference is too slow, then the human interaction will be harmed, and the interactive aspect of the probalistic model will be less useful. Unfortunately, the most popular inference algorithms in use today either require strong approximations which can degrade the quality of some models, or require time-consuming sampling. We explore the use of Iterated Conditional Modes, an algorithm which is able to obtain locally optimal maximum a posteriori estimates, as an alternative to popular inference algorithms such as Gibbs sampling or mean field variational inference. Iterated Conditional Modes algorithm is not only fast enough to facilitate human interaction, but can produce better maximum a posteriori estimates than sampling. We demonstrate the superior performance of Iterated Conditional Modes on a wide variety of models. First we use a DP Mixture of Multinomials model applied to the problem of web search result cluster, and show that not only can we outperform previous methods in clustering quality, but we can achieve interactive runtimes when performing inference with Iterated Conditional Modes. We then apply Iterated Conditional Modes to the Interactive Topic Model. Not only is Iterated Conditional Modes much faster than the previous published Gibbs sampler, but we are better able to incorporate human feedback during inference, as measured by accuracy on a classification task using the resultant topic model. Finally, we utilize Iterated Conditional Modes with MomResp, a model used to aggregate multiple noisy crowdsourced data. Compared with Gibbs sampling, Iterated Conditional Modes is better able to recover ground truth labels from simulated noisy annotations, and runs orders of magnitude faster.

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