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Hip fractures in older adults have severe effects on patients’ morbidity as well as mortality, so it is crucial to avoid this injury through the early identification of patients at high risk. Currently, the diagnosis of osteoporosis and consequently hip fracture risk is done through the measurement of bone mineral density by a dual-energy X-ray absorptiometry (DXA) scan. However, studies show that this method is not accurate enough, and a high percentage of patients who sustain a hip fracture had non-osteoporotic DXA scans less than a year before the incidence. In this research, to enhance the hip fracture risk prediction, the effect of a femur’s geometry and bone mineral density distribution was considered in the hip fracture risk estimation. This was done through 2D and 3D statistical shape and appearance modeling of the proximal femur using standard clinical DXA scans. To assess the proposed techniques, destructive mechanical tests were performed on 16 isolated cadaveric femurs. Also, through collaboration with the Canadian Osteoporosis Study (CaMos), the proposed statistical techniques to predict the hip fracture risk were evaluated in a clinical population as well. The results of this study showed that new techniques can enhance hip fracture risk estimation; in the clinical study, 2D and 3D statistical modeling were able to improve identifying patients at high risk by 40% and 44% over the clinical standard method. Also, the percentage of correct predictions using 2D statistical models did not differ significantly from the 3D predictions. Therefore, by applying these techniques in clinical practice it could be possible to identify patients at high risk of sustaining a hip fracture more accurately and eventually reduce the incidence of hip fractures and the pain and social and economic burden that comes with it. / Thesis / Doctor of Philosophy (PhD) / Diagnosis of osteoporosis and consequently hip fracture risk is based on the measurement of bone mineral density in clinical imaging called DXA scanning. However, studies have shown that this method is not sufficient in identifying all patients at high risk of sustaining a hip fracture. The purpose of this work was to incorporate the geometry and bone mineral density distribution of the proximal femur in hip fracture risk prediction through image processing of DXA scans. Two algorithms of 2D and 3D statistical shape and appearance modeling were implemented and evaluated in a cadaveric study (comparing the predicted fracture load to measured ones) as well as a clinical study (comparing the fracture predictions to the fracture history of patients). The results indicated that new techniques can enhance hip fracture risk estimation compared to the clinical standard method, and hence the devastating injury can be prevented through applying protective measures.

The U.S. health care system is one of the most expensive health care systems in the world, yet it is not as efficient as it is expected. Studies have shown that the use of expensive imaging procedures, such as CT scans, was significantly increasing for the past few years. However, the increased number of CT scans may not help to improve quality of care. No studies are conducted on investigate geographic variation on CT scan usage rate. This research is the first one to examine CT scan usage rate among counties and to examine variation caused by patient and hospital characteristics. We used the 2007 HCUP-SID database provided data for the research. GIS graph was used to illustrate geographic variation on CT scan usage in New York State. Contingency tables were developed to evaluate to what extent patient and hospital characteristics contribute to the variation. A logistic regression model was built to control the variation caused by patient and hospital characteristics in order to find variation contributed by other potential factors such as availability of CT scanners and radiologists. Significant geographic variation of CT scan usage rate in the county level of New York State was found. Patient demographics, insurance status and medical conditions as well as hospital bed size and teaching status were contributing factors to the variation. After controlling these factors, significant geographic variation was still found. It indicates that other potential reasons would influence the technology use. / Master of Science

Continuous advances in VLSI technology have led to more complex digital designs and shrinking transistor sizes. Due to these developments, design verification and manufacturing test have gained more importance and 70 % of the design expenditure in on validation processes. Electronic Design Automation (EDA) tools play a huge role in the validation process with various verification and test tools. Their efficiency have a high impact in saving time and money in this competitive market. Direct Acyclic Graphs (DAGs) are the backbone for most of the EDA tools. DAG is the most efficient data structure to store circuit information and also have efficient backt traversing structure which help in developing reasoning/ debugging tools. In this thesis, we focus on two such EDA tools using graphs as their underlying structure for circuit information storage • Scan pattern Debugger for Partial Scan Designs • Circuit SAT Bounded Model Checkers We developed a complete Interactive Scan Pattern Debugger Suite currently being used in the industry for next generation microprocessor design. The back end is an implication graph based sequential logic simulator which creates a Debug Implication Graph during the logic simulation of the failing patterns. An efficient node traversal mechanism across time frames, in the DIG, is used to perform the root-cause analysis for the failing scan-cells. In addition, the debugger provides visibility into the circuit internals to understand and fix the root-cause. We integrated the proposed technique into the scan ATPG flow for industrial microprocessor designs. We were able to resolve the First Silicon logical pattern failures within hours, which would have otherwise taken a few days of manual effort for root-causing the failure, understanding the root-cause and fixing it. For our circuit SAT implementation, we replace the internal implication graph used by the SAT solver with our debug implication graph (DIG). There is a high amount of circuit unrolling in circuit SAT/ BMC (Bounded Model Checking) problems which creates copies of the same combinational blocks in multiple time frames. This allows us to use the repetitive circuit structure and club it with the CNF database in the SAT solver. We propose a new data structure to store data in a circuit SAT solver which results up to 90% reduction in number of nodes. / Master of Science

Object detection and seafloor segmentation for conventional 2D side-scan sonar imagery is a well-investigated problem. However, due to recent advances in sensing technology, the side-scan sonar now produces a true 3D point cloud representation of the seafloor embedded with echo intensity. This creates a need to develop algorithms to process the incoming 3D data for applications such as object detection and segmentation, and an opportunity to leverage advances in 3D point cloud processing developed for terrestrial applications using optical sensors (e.g. LiDAR). A bottleneck in deploying 3D side-scan sonar sensors for online applications is attributed to the complexity in handling large amounts of data which requires higher memory for storing and processing data on embedded computers. The present research aims to improve data processing capabilities on-board autonomous underwater vehicles (AUVs). A supervoxel-based framework for over-segmentation and object detection is proposed which reduces a dense point cloud into clusters of similar points in a neighborhood. Supervoxels extracted from the point cloud are then described using feature vectors which are computed using geometry, echo intensity and depth attributes of the constituent points. Unsupervised density based clustering is applied on the feature space to detect objects which appear as outliers. / Master of Science / Acoustic imaging using side-scan sonar sensors has proven to be useful for tasks like seafloor mapping, mine countermeasures and habitat mapping. Due to advancements in sensing technology, a novel type of side-scan sonar sensor is developed which provides true 3D representation of the seafloor along with the echo intensity image. To improve the usability of the novel sensors on-board the carrying vehicles, efficient algorithms needs to be developed. In underwater robotics, limited computational and data storage capabilities are available which poses additional challenges in online perception applications like object detection and segmentation. In this project, I investigate a clustering based approach followed by an unsupervised machine learning method to perform detection of objects on the seafloor using the novel side scan sonar. I also show the usability of the approach for performing segmentation of the seafloor.

Les bases génétiques et l'histoire de la différenciation adaptative ont été étudiées chez les moules du complexe d'espèces Mytilus edulis qui représente un modèle d'étude intéressant pour mieux comprendre comment se propage et se distribue la différenciation adaptative en population structurée. Grâce à la technique AFLP, une approche de génomique des populations (« scan génomique ») a été utilisée pour mesurer la différenciation entre des populations isolées sur des échelles de temps et d'espaces contrastées. Notre objectif était de vérifier si la différenciation génétique n'avait pas une origine plus complexe qu'habituellement proposé. Trois parties s'articulent autour de cette question centrale. La première s'intéresse à la différenciation entre l'Atlantique et la Méditerranée chez l'espèce M. galloprovincialis et a montré que la structure génétique était la conséquence d'un différentiel d'introgression avec l'espèce sœur M. edulis. Dans la deuxième partie de ce travail nous avons mis en évidence qu'une sélection directe, soit balancée soit intermittente, sur un polymorphisme pré-existant expliquait le niveau de différenciation anormalement élevé d'un gène de l'immunité entre populations de la côte européenne chez M. edulis. Enfin, la troisième partie s'est intéressée à revisiter un exemple classique de la littérature de la génétique des populations: le cas des M. edulis du détroit de Long Island et a permis de suggérer que la structure observée à très petite échelle spatiale correspondait probablement à un contact secondaire entre des moules européennes introduites et les moules américaines. D'une manière générale nos résultats démontrent que, quelque soit l'échelle à laquelle nous nous plaçons, la différentiation génétique tire son origine d'une histoire souvent plus complexe qu'attendu. / The genetic basis and history of adaptive differentiation were studied in the species complex M. edulis which is an interesting model system to understand how adaptive differentiation spreads and structure itself in subdivided populations. Using the AFLP technique, a genome scan approach was undertaken to measure differentiation between populations on contrasted spacial and temporal scales. Our objective was to verify wether the origin of genetic differentiation could be more complex than anticipated. This question was addressed in three chapters. The first one focuses on the differentiation between populations of the Atlantic Ocean and Mediterranean Sea in M. galloprovincialis. Our results show that the genetic structure was the result of differential introgression with the sister hybridizing species M. edulis. In the second chapter of this work we demonstrated that direct selection on a pre-existing polymorphism explained the unusually high level of differentiation at a defensin locus between populations of the European coast in M. edulis. Finally, in the third chapter we revisited a classic example of the population genetics literature: the aminopeptidase cline in M. edulis populations of the Long Island Sound. We obtained evidence that the genetic differentiation observed at a very fine spatial scale in the sound was the consequence of a secondary contact between introduced mussels from Europe and indigenous American mussels. Whatever the spatio-temporal scale at which we analyzed genetic differentiation, its origin proved to originate from an unsuspectedly long and complex history.

Introdução: O aumento na prevalência das doenças cardiovasculares alerta para a necessidade de estratégias eficazes e de baixo custo como medidas preventivas na redução dos fatores de risco, morbidades e óbitos decorrentes de eventos coronarianos. As modificações no estilo de vida são as primeiras alternativas a serem adotadas. Nesse contexto, a dieta ocupa lugar de destaque e os benefícios dos ácidos graxos poli-insaturados ômega-3 na saúde cardiovascular são amplamente reconhecidos. As doenças cardiovasculares são influenciadas por diversos fatores de risco e o desequilíbrio na concentração plasmática das lipoproteínas é um fator de risco independente no desenvolvimento da doença cardiovascular aterosclerótica. Entretanto, há evidências de que as subfrações lipoproteicas podem influenciar o risco cardiovascular de maneira diferenciada, dependendo das características físico-químicas e funcionalidade de cada partícula. O desenvolvimento de novas técnicas, capazes de identificar esses parâmetros, tem sido foco de grande interesse científico. Objetivo: Avaliar o papel do ômega-3 sobre as características físico-químicas da LDL e HDL e possível associação entre medidas Z-scan e marcadores cardiometabólicos em indivíduos adultos. Metodologia: A partir de uma subamostra do estudo CARDIONUTRI (estudo clínico, randomizado, controlado e duplo cego com seguimento de 8 semanas) foram selecionados 36 indivíduos do Grupo Ômega-3 (3,0g/dia de óleo de peixe - 1,11g de EPA + 0,69g de DHA) e 27 do Grupo Placebo (3,0g/dia de óleo mineral). Foram monitorados o perfil clínico, antecedentes familiares, consumo alimentar, atividade física e antropometria. Amostras de sangue foram coletadas após 12 horas de jejum para avaliação das concentrações plasmáticas de CT, TAG, HDL-C, LDL-C, APOAI, APOB, PON1 e glicose. O tamanho da HDL e LDL foi analisado pelo método padronizado Lipoprint®. O conteúdo de LDL(-) foi determinado por ELISA. As medidas Z-scan foram determinadas por meio da difusividade térmica e absorção linear da LDL (1,0 mg/dL de proteína), isolada por ultracentrifugação. Todos as variáveis do estudo foram avaliadas no momento basal e após 8 semanas de intervenção. A adesão à intervenção foi monitorada pela contagem de cápsulas e percentual dos ácidos graxos plasmáticos. Para avaliar a associação das medidas Z-Scan aos marcadores cardiometabólicos, os dados obtidos no momento basal foram submetidos à Análise de Componentes Principais. Resultados: A idade média dos participantes do estudo foi de 51,5 (10,5) anos. A suplementação com ômega-3 promoveu redução significativa de CT, TAG, não-HDL, HDLPEQUENA e LDL(-), além de aumento significativo de HDL-C e HDLGRANDE. O ômega-3 foi mais eficaz na redução dos TAG (29,2 por cento ) quando comparado ao placebo (2,9 por cento ). O Grupo Ômega-3 apresentou aumento de HDLGRANDE (16,9 por cento ) e redução de HDLPEQUENA (-16,3 por cento ) ao final da intervenção, com diferença significativa quando comparado ao Grupo Placebo que apresentou redução de HDLGRANDE (-4,8 por cento ) e aumento de HDLPEQUENA (17,7 por cento ). Não foram observadas diferenças nas medidas Z-scan após a intervenção, porém as medidas se associaram positivamente a Componentes Principais com padrões cardioprotetores da amostra e negativamente a padrões aterogênicos. Conclusão: O ômega-3 demonstrou efeito positivo no perfil lipídico e propriedades aterogênicas das subfrações lipoproteicas. A suplementação com ômega-3 não modificou as medidas Z-scan, no entanto, a técnica demonstrou ser uma ferramenta capaz de se associar a padrões aterogênicos e antiaterogênicos monitorados no presente estudo / Introduction: The increased of cardiovascular disease prevalence draws attention to the need to adopt effective and inexpensive strategies as preventive measures to reduce risk factors, morbidity and deaths from coronary events. Lifestyle modification is indicated as first alternative to be adopted. In this context the diet stands out and omega-3 polyunsaturated fatty acids benefits on cardiovascular health are largely recognized. Cardiovascular diseases are influenced by several risk factors and the plasma imbalance lipoprotein is considered a crucial independent risk factor. However, there is evidence of the influence of lipoprotein subfractions in cardiovascular risk, based on the physicochemical characteristics of these particles. The development of new techniques able to identify those parameters has been the focus of great scientific interest. Objective: To evaluate the role of omega-3 on HDL and LDL physicochemical characteristics and possible association between Z-scan measurements and cardiometabolic markers in adults. Methods: From a subsample of the study CARDIONUTRI (clinical, randomized, controlled, double blind study with 8-week follow-up) were selected 36 individuals from the Omega-3 Group (3.0g/day of fish oil - 1,11g EPA + 0.69g DHA) and 27 individuals from the Placebo Group (3.0g/day of mineral oil). The clinical profile, family history, dietary intake, physical activity and anthropometry were monitored. Blood samples were collected after 12 hours of fasting to evaluate plasma concentrations of TC, TAG, HDL-C, LDL-C, APOAI, APOB, PON1 and glucose. The HDL and LDL size was analyzed by the standard method Lipoprint®. The levels of LDL (-) was determined by ELISA. The Z-scan measurements were determined by thermal diffusivity and linear absorption of LDL (1.0 mg / dL protein) isolated by ultracentrifugation. All study variables were evaluated at baseline and after 8 weeks of intervention. The intervention accession was monitored by capsule count and percentage of plasma fatty acids. To evaluate the association of the Z-Scan measurements to cardiometabolic markers, the data collected at baseline were subjected to Principal Component Analysis. Results: The average age of individuals were 51.5 (10.5) years. The omega-3 supplementation promoted a significant decreased of TC, TAG, non-HDL, small HDL and LDL(-), and significantly increased HDL-C and large HDL. The omega-3 was more effective in reducing the TAG (29.2 per cent ) when compared to placebo (2.9 per cent ). The Omega-3 Group increased large HDL (16.9 per cent ) and decreased small HDL (-16.3 per cent ) after the intervention, with significant difference when compared to the Placebo Group that decreased large HDL (-4.8 per cent ) and increased small HDL (17.7 per cent ). There were no differences in Z-scan measurements with the interventions, but were observed positively associated the Z-scan measurements with the anti-atherogenic sample patterns and negatively associated with atherogenic sample patterns when the sample was standardized from the Principal Components Analysis. Conclusion: The omega-3 demonstrated positive effect on the lipid profile and atherogenic lipoprotein subfractions. Supplementation with omega-3 did not modify the Z-scan measurements, however, the technique proved to be a tool that can be associated with atherogenic and anti-atherogenic sample patterns monitored in this study.

Neste trabalho estudamos as propriedades térmicas e óticas de íons emissores usando as técnicas de lente térmica e z-scan, resolvidas no tempo. Foram obtidos o espectro fototérmico de lente térmica de amostras dopadas com Yb3+ e diversos outros parâmetros fototérmicos. Foi também realizado um estudo dos efeitos da saturação da não linearidade ótica sobre a determinação das propriedades eletrônicas em sólidos dopados com Cr3+, utilizando a técnica de z-scan. A seguir a mesma técnica foi aplicada na obtenção do parâmetro de upconversion em materiais dopados com Nd3+ e Cr3+ (com excitação ressonante e não ressonante ao nível laser emissor). Empregando a integral de difração foram investigados os efeitos do processo de upconversion Auger sobre a refração não linear. Os resultados experimentais e numéricos mostraram uma excelente concordância. Também foi investigado o comportamento temporal da população do nível emissor na fase de excitação, demonstrando assim uma forma alternativa de obter o parâmetro de upconversion. Finalmente, usando a técnica de z-scan obtivemos a forma de linha da não linearidade ótica de uma amostra dopada com Yb3+ onde demonstramos que a contribuição mais importante para a não linearidade do íon advém de transições no UV, mesmo estando o íon sob excitação ressonante ao nível emissor. / In this work we have studied the thermal and optical properties of emitters ions by using the thermal lens and z-scan time resolved techniques. It was obtained the thermal lens photothermal spectra of Yb3+ doped samples, and several other photothermal parameters. Also, it was done a study on the optical nonlinearity saturation effects over the determination of the optical properties in Cr3+ doped solids, using the z-scan technique. In the sequence the same technique was used in order to obtain the upconversion parameter in Nd3+ and Cr3+ doped materials (with excitation resonant and non resonant to the emitter level). Employing the diffraction integral, the effects of Auger upconversion process on the nonlinear refraction were investigated. The experimental and numerical results agree very well. It was also investigated the temporal behavior of the emitter level population during the excitation process, showing an alternative way to obtain the upconvertion parameter. Finally, by using the z-scan technique we have obtained the optical nonlinear lineshape of a Yb3+ doped sample, and demonstrated that the major contribution to the optical non linearity arises from the UV transitions, even when the emitter level of the ion is under resonant excitation.

Made available in DSpace on 2017-07-21T19:25:58Z (GMT). No. of bitstreams: 1 Vinicius Mariani Lenart.pdf: 3756287 bytes, checksum: 06003df7bdc1780a870fa9cccf057a14 (MD5) Previous issue date: 2010-04-28 / A modern branch of condensed matter physics is the study of unconventional fluids related to the class of "soft matter". Liquid crystalline systems are major sources of research in fundamental and applied physics. In this sense, many materials with these properties are widely produced and studied in order to understand and apply their properties in new technologies. A liquid crystal often used as a component in displays is E7. But recently have been studied a new class of functional materials that besides the liquid crystalline behavior has the property of emitting light. This work aims to study the nematic-isotropic phase transition of the liquid crystal E7, pure and doped with these new materials through the parameters of nonlinear optical obtained using the technique of Z-scan and also to measure changes in nonlinear optical properties of E7 due to this addition. / Um ramo moderno da Física da matéria condensada é o estudo de fluidos não convencionais referentes a classe das "substâncias frágeis". Sistemas líquidos cristalinos são grandes fontes de pesquisas tanto em física fundamental quanto em aplicada. Nesse sentido, muitos materiais com estas propriedades são vastamente produzidos e pesquisados com o objetivo de entender e aplicar suas propriedades em novas tecnologias. Um cristal líquido muito utilizado como componente em mostradores é o E7. Porém recentemente vêm sendo estudada uma nova classe de materiais funcionais que além do comportamento líquido cristalino apresenta a propriedade de emitir luz. Este trabalho tem por objetivo, estudar a transição de fase nemático-isotrópica do cristal líquido E7 puro e dopado com estes novos materiais por meio de parâmetros ópticos não lineares obtidos através da técnica de Z-scan e também aferir as alterações nas propriedades ópticas não lineares do E7 causadas por essa adição.

As técnicas de lente térmica (LT) e \"Z-scan\" foram usadas para estudar as propriedades termo-óticas (difusividade térmica, condutividade térmica, taxa de variação do caminho ótico em função da temperatura e eficiência quântica de fluorescência) e não-lineares (partes real e imaginária do índice de refração não-linear, diferença de polarizabilidade e da seção de choque de absorção entre os estados excitado e fundamental, respectivamente) de sólidos dopados com Neodímio e Cromo. Uma nova extensão da técnica de LT foi proposta para determinar a eficiência quântica de fluorescência sem necessitar de amostra referência, como é feito na maioria dos métodos fototérmicos. Além disso, ambas técnicas foram usadas como espectroscopia, ou seja, a LT foi usada para estudar a forma de linha do calor gerado no material quando a excitação é feita próximo da banda de absorção do material, possibilitando assim a determinação da eficiência de transferência entre a matriz e o íon dopante, e a técnica \"Z-scan\" foi adaptada para medir a forma de linha do índice de refração não-linear próximo das linhas de emissão laser nos cristais dopados com Cromo. / The Thermal Lens (TL) and Z-scan technique were used to study the thermo-optical (thermal diffusivity, thermal conductivity, temperature coefficient of the optical path length change and fluorescence quantum efficiency) and nonlinear optical (parts real and imaginary of the refractive index, polarizability difference and absorption cross section between the excited and ground states, respectively) properties of Neodymium and Chromium doped solids. A new extension of the TL technique was proposed to determine the fluorescence quantum efficiency without measuring a reference sample, as done by any photothermal method Moreover, both techniques were used as an spectroscopy one, i. e., the TL was used to study the line shape of the heat created in material when the excitation is done near at the host absorption band, allowing the determination of the energy transfer efficiency between the host and the dopant ion, and the 2-scan technique was adapted to measure the line shape of the nonlinear refractive index near the laser lines in Chromium doped crystals.