Thesis (Ph. D.)--Case Western Reserve University, 2008. / Frances Payne Bolton [School of Nursing]. Includes bibliographical references.

No description available.

This dissertation consists of two essays on predictability of asset prices. "Benchmarking problems and long horizon abnormal returns" and, "Low R-square in the cross section of expected returns". Long run abnormal returns following Initial Public Offerings (IPOs), Seasoned Equity Offers (SEO) and other firm level events are well documented in the finance literature. These findings are difficult to reconcile in an efficient markets world. I examine the seriousness of potential benchmarking errors on the measurement of abnormal returns. I find that the simpler, more parsimonious models perform better in practice and finds that excess performance is not predictable regardless of the APM. Thus, the long run underperformance following SEOs found in the literature is consistent with market efficiency because excess performance itself is not predictable. In the other essay, "Low R-square in the cross section of expected returns", I examine the “low R-square” phenomenon observed in the literature. CAPM predicts exact linear relationship between return and betas (SML). This means that estimated time series betas for firms should be related with firms' future returns. However, the estimated betas have almost no relationship with future returns. The cross-sectional R2 are surprising low (3% average) while time series R2 are higher (around 30 % average). He develops a simple asset pricing model that explains this phenomenon. Even in a perfect world where there are no errors in the benchmark measurement or estimation of the price of market risk the difference in R-squares can be quite large due to the difference in variance between the "market" and average returns. I document that market variance exceeds the variance of average returns, with few exceptions, for the last 74 years.

Obesidade é o acúmulo excessivo ou anormal de gordura em relação à massa magra, podendo ser modificada por fatores ambientais, genéticos e comportamentais. Na literatura, é bem estabelecida a associação entre diabetes, tabagismo e, mais recentemente, obesidade e periodontite. Entretanto, estudos de prevalência e de associação entre obesidade e gengivite ainda são bastante escassos, especialmente em indivíduos adultos. O presente estudo objetivou verificar a associação entre obesidade e diferentes fatores sociodemográficos, médico-odontológicos e comportamentais em uma amostra de indivíduos adultos da cidade de Porto Alegre, Brasil. Esse estudo, de caráter epidemiológico transversal, avaliou 614 indivíduos maiores de 18 anos. Foram incluídos apenas os indivíduos com pelo menos quatro dentes em boca e que não utilizem aparelhos ortodônticos fixos. Os participantes foram identificados por meio de uma amostragem probabilística multi-estágios, considerando também a distribuição de acordo com o gênero e faixa etária. Dez setores censitários foram visitados. Uma entrevista estruturada foi realizada por pesquisadores treinados, obtendo-se informação de gênero, idade, hábitos comportamentais e estado de saúde sistêmica. Um examinador treinado e calibrado realizou exames de Índice de Placa Visível, Índice gengival de Löe-Silness, modificado por Löe, e cálculo. Além disso, peso, altura e percentual de gordura, obtido através de um aparelho portátil de microcorrente elétrica, também foram coletados. Regressão multivariada de Poisson foi utilizada para avaliar a associação entre obesidade e os diferentes fatores médico-odontológicos e sociodemográficos. Dos indivíduos examinados, 33,89% foram classificados como obesos por apresentarem índice de massa corporal pelo menos de 30 kg/m². Observou-se que gênero feminino, hipertensão autorreportada, não fumar, maiores percentuais de placa visível e maior número de dentes presentes apresentaram associação estatisticamente significativa com obesidade quando comparados com indivíduos não obesos. Concluiu-se que a ocorrência de obesidade, na presente amostra, foi alta e que o gênero feminino, não fumar e maiores percentuais de placa estiveram associados com a obesidade. Contudo, nenhuma associação estatisticamente significativa foi estabelecida entre gengivite e obesidade. / Obesity is the excessive or abnormal accumulation of fat in relation to lean body mass that may be modified by environmental, genetic and behavioral factors. It is well established the relationship between diabetes, smoking and, more recently, obesity and periodontitis. However, studies regarding the association between obesity and gingivitis are quite scarce, especially in adults. This study aimed to verify the association between obesity and different sociodemographic, medical, dental and behavioral factors in a sample of adults in the city of Porto Alegre, Brazil. This is as an epidemiological cross-sectional study that evaluated 614 subjects with at least 18 years old. Only subjects with the minimum of four teeth and those who did not use fixed orthodontic appliances were included. Participants were identified through a multi-stage probability sampling, considering the distribution according to gender and age. Ten census tracts were visited. A structured interview was conducted by trained researchers to collect information about gender, age, behavioral habits and systemic impaired conditions. A trained and calibrated examiner performed the Plaque Visible Index, Löe-Sillness Gingival Index modified by Löe and calculus. Additionally, weight, height and body fat percentage, obtained through a portable electrical microcurrent, were collected. Multivariate Poisson regression was used to evaluate the association between obesity and the sociodemographic, medical, dental and behavioral factors. Obesity, defined as body mass index ≥30kg/m2, were found in 33.89% of the examined subjects. It was showed that females, self-reported hypertension, no smoking, higher visible plaque percentage, and bigger number of teeth were significantly associated with obesity compared to non-obese subjects. It was concluded that the occurrence of obesity was high and that females, never/former smokers and larger plaque percentages were associated with obesity. However, no statistically significant association was established between gingivitis and obesity.

Obesidade é o acúmulo excessivo ou anormal de gordura em relação à massa magra, podendo ser modificada por fatores ambientais, genéticos e comportamentais. Na literatura, é bem estabelecida a associação entre diabetes, tabagismo e, mais recentemente, obesidade e periodontite. Entretanto, estudos de prevalência e de associação entre obesidade e gengivite ainda são bastante escassos, especialmente em indivíduos adultos. O presente estudo objetivou verificar a associação entre obesidade e diferentes fatores sociodemográficos, médico-odontológicos e comportamentais em uma amostra de indivíduos adultos da cidade de Porto Alegre, Brasil. Esse estudo, de caráter epidemiológico transversal, avaliou 614 indivíduos maiores de 18 anos. Foram incluídos apenas os indivíduos com pelo menos quatro dentes em boca e que não utilizem aparelhos ortodônticos fixos. Os participantes foram identificados por meio de uma amostragem probabilística multi-estágios, considerando também a distribuição de acordo com o gênero e faixa etária. Dez setores censitários foram visitados. Uma entrevista estruturada foi realizada por pesquisadores treinados, obtendo-se informação de gênero, idade, hábitos comportamentais e estado de saúde sistêmica. Um examinador treinado e calibrado realizou exames de Índice de Placa Visível, Índice gengival de Löe-Silness, modificado por Löe, e cálculo. Além disso, peso, altura e percentual de gordura, obtido através de um aparelho portátil de microcorrente elétrica, também foram coletados. Regressão multivariada de Poisson foi utilizada para avaliar a associação entre obesidade e os diferentes fatores médico-odontológicos e sociodemográficos. Dos indivíduos examinados, 33,89% foram classificados como obesos por apresentarem índice de massa corporal pelo menos de 30 kg/m². Observou-se que gênero feminino, hipertensão autorreportada, não fumar, maiores percentuais de placa visível e maior número de dentes presentes apresentaram associação estatisticamente significativa com obesidade quando comparados com indivíduos não obesos. Concluiu-se que a ocorrência de obesidade, na presente amostra, foi alta e que o gênero feminino, não fumar e maiores percentuais de placa estiveram associados com a obesidade. Contudo, nenhuma associação estatisticamente significativa foi estabelecida entre gengivite e obesidade. / Obesity is the excessive or abnormal accumulation of fat in relation to lean body mass that may be modified by environmental, genetic and behavioral factors. It is well established the relationship between diabetes, smoking and, more recently, obesity and periodontitis. However, studies regarding the association between obesity and gingivitis are quite scarce, especially in adults. This study aimed to verify the association between obesity and different sociodemographic, medical, dental and behavioral factors in a sample of adults in the city of Porto Alegre, Brazil. This is as an epidemiological cross-sectional study that evaluated 614 subjects with at least 18 years old. Only subjects with the minimum of four teeth and those who did not use fixed orthodontic appliances were included. Participants were identified through a multi-stage probability sampling, considering the distribution according to gender and age. Ten census tracts were visited. A structured interview was conducted by trained researchers to collect information about gender, age, behavioral habits and systemic impaired conditions. A trained and calibrated examiner performed the Plaque Visible Index, Löe-Sillness Gingival Index modified by Löe and calculus. Additionally, weight, height and body fat percentage, obtained through a portable electrical microcurrent, were collected. Multivariate Poisson regression was used to evaluate the association between obesity and the sociodemographic, medical, dental and behavioral factors. Obesity, defined as body mass index ≥30kg/m2, were found in 33.89% of the examined subjects. It was showed that females, self-reported hypertension, no smoking, higher visible plaque percentage, and bigger number of teeth were significantly associated with obesity compared to non-obese subjects. It was concluded that the occurrence of obesity was high and that females, never/former smokers and larger plaque percentages were associated with obesity. However, no statistically significant association was established between gingivitis and obesity.

Obesidade é o acúmulo excessivo ou anormal de gordura em relação à massa magra, podendo ser modificada por fatores ambientais, genéticos e comportamentais. Na literatura, é bem estabelecida a associação entre diabetes, tabagismo e, mais recentemente, obesidade e periodontite. Entretanto, estudos de prevalência e de associação entre obesidade e gengivite ainda são bastante escassos, especialmente em indivíduos adultos. O presente estudo objetivou verificar a associação entre obesidade e diferentes fatores sociodemográficos, médico-odontológicos e comportamentais em uma amostra de indivíduos adultos da cidade de Porto Alegre, Brasil. Esse estudo, de caráter epidemiológico transversal, avaliou 614 indivíduos maiores de 18 anos. Foram incluídos apenas os indivíduos com pelo menos quatro dentes em boca e que não utilizem aparelhos ortodônticos fixos. Os participantes foram identificados por meio de uma amostragem probabilística multi-estágios, considerando também a distribuição de acordo com o gênero e faixa etária. Dez setores censitários foram visitados. Uma entrevista estruturada foi realizada por pesquisadores treinados, obtendo-se informação de gênero, idade, hábitos comportamentais e estado de saúde sistêmica. Um examinador treinado e calibrado realizou exames de Índice de Placa Visível, Índice gengival de Löe-Silness, modificado por Löe, e cálculo. Além disso, peso, altura e percentual de gordura, obtido através de um aparelho portátil de microcorrente elétrica, também foram coletados. Regressão multivariada de Poisson foi utilizada para avaliar a associação entre obesidade e os diferentes fatores médico-odontológicos e sociodemográficos. Dos indivíduos examinados, 33,89% foram classificados como obesos por apresentarem índice de massa corporal pelo menos de 30 kg/m². Observou-se que gênero feminino, hipertensão autorreportada, não fumar, maiores percentuais de placa visível e maior número de dentes presentes apresentaram associação estatisticamente significativa com obesidade quando comparados com indivíduos não obesos. Concluiu-se que a ocorrência de obesidade, na presente amostra, foi alta e que o gênero feminino, não fumar e maiores percentuais de placa estiveram associados com a obesidade. Contudo, nenhuma associação estatisticamente significativa foi estabelecida entre gengivite e obesidade. / Obesity is the excessive or abnormal accumulation of fat in relation to lean body mass that may be modified by environmental, genetic and behavioral factors. It is well established the relationship between diabetes, smoking and, more recently, obesity and periodontitis. However, studies regarding the association between obesity and gingivitis are quite scarce, especially in adults. This study aimed to verify the association between obesity and different sociodemographic, medical, dental and behavioral factors in a sample of adults in the city of Porto Alegre, Brazil. This is as an epidemiological cross-sectional study that evaluated 614 subjects with at least 18 years old. Only subjects with the minimum of four teeth and those who did not use fixed orthodontic appliances were included. Participants were identified through a multi-stage probability sampling, considering the distribution according to gender and age. Ten census tracts were visited. A structured interview was conducted by trained researchers to collect information about gender, age, behavioral habits and systemic impaired conditions. A trained and calibrated examiner performed the Plaque Visible Index, Löe-Sillness Gingival Index modified by Löe and calculus. Additionally, weight, height and body fat percentage, obtained through a portable electrical microcurrent, were collected. Multivariate Poisson regression was used to evaluate the association between obesity and the sociodemographic, medical, dental and behavioral factors. Obesity, defined as body mass index ≥30kg/m2, were found in 33.89% of the examined subjects. It was showed that females, self-reported hypertension, no smoking, higher visible plaque percentage, and bigger number of teeth were significantly associated with obesity compared to non-obese subjects. It was concluded that the occurrence of obesity was high and that females, never/former smokers and larger plaque percentages were associated with obesity. However, no statistically significant association was established between gingivitis and obesity.

Approximately 15 million Americans are diagnosed with a major depressive disorder each year, with higher rates among women and college-aged adults. Recent research suggests a vitamin D insufficiency may be associated with an increased risk of depression among the elderly. However, studies have not been conducted among young women. A recent study of young adults in Massachusetts suggests that two-thirds of this population is vitamin D deficient. We evaluated the association between dietary vitamin D intake and serum levels of 25-hydroxyvitamin D (25(OH)D3) and history of depression using data from the UMass Vitamin D Status Study, a cross-sectional study of 237 college-aged women. Information on depression and health-related factors was collected by questionnaire at a single clinic visit. Dietary vitamin D intake was assessed by a Food Frequency Questionnaire, and serum 25(OH)D3 levels were assessed in fasting blood samples by radioimmunoassay. In multivariable analyses, we observed the suggestion of an association between vitamin D from food sources and history of depression. For each 100 IU/day increase of dietary vitamin D there is a 13% decreased risk of depression (95% CI: 0.6, 1.2). However, total vitamin D intake (foods and supplements combined) was not associated with history of depression. Compared to women in the lowest tertile (median=51 nmol/L) of serum 25(OH)D3, women in the second tertile (median=72 nmol/L) had an 82% decreased risk of depression (95% CI: 0.04, 0.90; ptrend=0.008). The results of this study are consistent with vitamin D as a modifiable risk factor for depression and may inform intervention studies among college-aged women.

Ma, Ka Lim. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves [110]-117). / Abstracts in English and Chinese. / Chapter 1 --- Radon Transform and Medical Tomography --- p.1 / Chapter 1.1 --- Computed Tomography --- p.2 / Chapter 1.2 --- Emission Computed Tomography --- p.4 / Chapter 1.2.1 --- SPECT --- p.5 / Chapter 1.2.2 --- PET --- p.6 / Chapter 1.3 --- Radon Transform --- p.8 / Chapter 1.3.1 --- Properties of Radon Transform --- p.10 / Chapter 1.3.2 --- Fourier Slice Theorem --- p.11 / Chapter 1.4 --- Research Objective --- p.12 / Chapter 2 --- Popular Tomographic Reconstruction Algorithms --- p.14 / Chapter 2.1 --- Analytic Method --- p.15 / Chapter 2.1.1 --- Direct Fourier Method (DFM) --- p.15 / Chapter 2.1.2 --- Backprojection (BP) --- p.17 / Chapter 2.1.3 --- Backprojection Filtering (BPF) --- p.19 / Chapter 2.1.4 --- Filtered Backprojection (FBP) --- p.21 / Chapter 2.2 --- Iterative Method --- p.23 / Chapter 2.2.1 --- Maximum Likelihood - Expectation Maximization (ML-EM) --- p.25 / Chapter 2.2.2 --- Ordered Subsets Expectation Maximization (OSEM) --- p.27 / Chapter 3 --- Consistent Reconstruction --- p.30 / Chapter 3.1 --- Directional Filter Bank (DFB) --- p.30 / Chapter 3.1.1 --- Interpolation in horizontal function space --- p.32 / Chapter 3.1.2 --- Directional Multiresolution Analysis --- p.33 / Chapter 3.1.3 --- Iterated Filter Bank Equivalence --- p.36 / Chapter 3.1.4 --- Vertical Directional Function Space --- p.38 / Chapter 3.1.5 --- Summary --- p.40 / Chapter 3.2 --- Reconstruction Scheme --- p.42 / Chapter 3.2.1 --- Choices for basis function 6m --- p.43 / Chapter 3.2.2 --- Choices for coordinate mapping function wm --- p.46 / Chapter 3.2.3 --- Summary --- p.49 / Chapter 3.3 --- Experiment --- p.49 / Chapter 3.3.1 --- Experiment for consistent reconstruction with different choices --- p.50 / Chapter 3.3.2 --- Experiment for comparison with different reconstruction methods --- p.54 / Chapter 3.4 --- Conclusion --- p.56 / Chapter 4 --- Tomographic Denoising --- p.57 / Chapter 4.1 --- SURE-LET and PURE-LET denoising --- p.59 / Chapter 4.1.1 --- SURE-LET --- p.60 / Chapter 4.1.2 --- PURE-LET --- p.62 / Chapter 4.2 --- Experiment --- p.64 / Chapter 4.2.1 --- Experiment on SURE-LET Denoising --- p.65 / Chapter 4.2.2 --- Experiment on PURE-LET Denoising --- p.69 / Chapter 4.2.3 --- Conclusion --- p.76 / Chapter 5 --- Sinogram Retrieval --- p.77 / Chapter 5.1 --- Sinogram Retrieval Method --- p.78 / Chapter 5.1.1 --- MATLAB Radon Function --- p.79 / Chapter 5.1.2 --- Subordinate Gradient (SG) Algorithm --- p.81 / Chapter 5.1.3 --- Orthonormal Subordinate Gradient (OSG) Algorithm --- p.81 / Chapter 5.2 --- Experiment --- p.84 / Chapter 5.2.1 --- Limitation of Sinogram Retrieval --- p.84 / Chapter 5.2.2 --- Comparison of Sinogram Retrieval Algorithms --- p.86 / Chapter 5.2.3 --- Embedded in Tomographic Reconstruction --- p.88 / Chapter 5.2.4 --- Embedded in Tomographic Denoising --- p.90 / Chapter 5.3 --- Conclusion --- p.96 / Chapter 6 --- Conclusion --- p.97 / Chapter 6.1 --- Summary --- p.97 / Chapter 6.1.1 --- Tomographic Reconstruction --- p.97 / Chapter 6.1.2 --- Tomographic Denoising --- p.98 / Chapter 6.1.3 --- Sinogram Retrieval --- p.98 / Chapter 6.2 --- Future Research --- p.99 / Chapter 6.2.1 --- Tomographic Reconstruction --- p.99 / Chapter 6.2.2 --- Tomographic Denoising --- p.99 / Chapter 6.2.3 --- Sinogram Retrieval --- p.99 / Chapter A --- Examples of Radon Transform --- p.100 / Chapter B --- Experimental Phantom Image --- p.104 / Chapter C --- Results of sinogram retrieval experiments --- p.107 / Bibliography --- p.110

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Previous studies suggest that dietary patterns that promote acidosis may have a negative effect on bone density, whereas a more alkaline‐based profile would be associated with better bone health. Thus, the aim of this study was to assess, in omnivores, vegetarians, and vegans bone mineral density using Dual‐energy X‐ray absorptiometry (DEXA) and compare it to their acid‐base status as indicated by urinary pH, Potential Renal Acid Load (PRAL) and serum anion gap. Our hypothesis was that plant‐based diets would be associated with a more alkaline acid‐base profile than omnivorous diets, and thus have a higher bone mineral density. Methods: We conducted a cross‐sectional study where we compared plant based vs. omnivorous diets. Eighty‐two subjects were enrolled in the study (27 omnivores, 27 vegetarians, and 28 vegans). Subjects were asked to fill out a medical history form and a 24‐ hour diet recall, and to complete a 24‐hour urine collection. After a few weeks, subjects returned to the test site to complete a DEXA scan. Acid base‐balance and bone health were determined using PRAL, urine pH, and anion gap as biomarkers for pH, and DEXA as an indicator of bone density. Our results showed that bone mineral density did not differ significantly between groups, although lacto‐ovo and vegan diets were more alkaline compared to meat based diets (6.5  0.4, 6.7  0.4, and 6.2  0.4 pH respectively, p = 0.003). Protein intake was found to be reduced by ~30% in individuals adhering to a lacto‐ovarian or vegan diet; yet protein was only associated with bone mineral density in those following vegan diets. Conversely, urinary pH was associated with bone mineral density only in those following a meat‐based diet. The significance of this study is that it provides knowledge in the area of osteoporosis prevention and perhaps specific recommendations based on diet groups: increased fruit and vegetable intake for those with high meat consumption, to improve the acid‐base homeostasis, and increased plant protein intake for individuals who follow a plant-based diet.

Hip fracture has been identified as a major worldwide health problem among the elderly population. A fast, accurate and effective evaluation of hip fracture risk is essential for accurate health care planning and selecting a proper treatment. Therefore, the high applicability and the universal availability are required for assessing a technique. The objective of this study was to develop a two-dimensional subject-specific beam model, which is easy to be adopted into a clinical environment to assess hip fracture risk. First, the equivalence between CTXA (computed tomography X-ray absorptiometry) and QCT (quantitative computed tomography) derived femur cross-section stiffness was studied. Then, the CTXA-based femur cross-section stiffness was used in the beam model to calculate the hip fracture risk index (FRI) during sideways fall and single-leg stance loading configuration. Finally, the test of discrimination between PPI (proton-pump inhibitor) users and non-PPI users based on cross-sectional stiffness, BMD (bone mineral density) and FRI was conducted to demonstrate if PPI use is associated with the presence of osteoporosis or accelerated BMD loss. Strong correlation is found between CTXA and QCT derived femur cross-section stiffness, which indicates that QCT can be replaced by CTXA in assessing femur bone quality. Therefore, DXA can be a replacement of QCT to calculate femur cross-sectional properties due to the equivalence between CTXA and DXA derived mechanical properties. It is also demonstrated that the cross-sectional stiffness, BMD, and FRI cannot discriminate the PPI users from non-PPI users, which means that there is no difference between PPI users and non-PPI users in cross-sectional stiffness, BMD, and FRI. This may suggested that PPI use is not associated with the presence of osteoporosis or accelerated BMD loss. The proposed beam model can be easily adopted into clinic to predict hip fracture risk, and this beam model derived FRI can be used in some clinical verification. Yet its accuracy of discriminate fracture will be investigated in a future study. / May 2017