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An Exploration of Adolescent Obesity DeterminantsSmith, Anastasia King 13 May 2016 (has links)
In 2010, approximately two-thirds of adults and one-fifth of the adolescent population in the United States were considered either overweight or obese, resulting in the United States having the highest per capita obesity rate among all OECD countries. A considerable body of literature regarding health behavior, health outcomes, and public policy exists on what the Centers for Disease Control and Prevention considers an obesity epidemic. In response to the growing problem of childhood obesity, the Child Nutrition and WIC Reauthorization Act of 2004 (CNRA), which required that schools participating in the National School Lunch Program and/or School Breakfast Program have wellness policies on file, was passed.
The purpose of this research is to provide additional insight into the origin of the geographic variation in adolescent obesity rates between the U.S. states. Previous research has looked at differences in built environments, maternal employment, food prices, agriculture policies, and technology factors in an effort to explain the variation in adolescent obesity prevalence. This dissertation contributes to the literature by examining the hypothesis that state-level school wellness policies also played a role in determining the rates of childhood obesity. Using School Health Policies and Practices Study (SHPPS) surveys from 2000 – 2012, I derived a state-level school wellness policy measure. This, together with Youth Risk Behavior Surveillance survey data on adolescent BMI was used to measure the effect of the wellness policy mandate on adolescent obesity prevalence. Several models were applied to first demonstrate that the state of residence for an adolescent is indeed related to BMI trends and then to investigate various determinants of adolescent obesity including the primary variable of interest, state school wellness policies.
The results of this research provide evidence of a statistically significant, although very small positive effect of school wellness policies on adolescent BMI that is contrary to my hypothesis. Dominance analysis showed that of the four wellness policy factors considered in the principal component composition of the wellness policy measure, policy components that met state requirements rather than those meeting health screen criteria, state recommendations, and national standards were most important in explaining the overall variance of the regression model. Interestingly, the public school attendance rate itself was also associated with a substantial decrease in adolescent BMI.
Understanding the determinants of adolescent obesity and how to effect change in the rising trend is a national concern. Obese adolescents are at significant risk of becoming obese adults and previous research has already shown the high economic costs associated with adult obesity and its comorbidities. Policies implemented in school, where adolescents consume a considerable portion of their daily calories and participate in physical activity, can help to build healthy habits that have the potential to lower the probability of an adolescent becoming an obese adult. Over time, a healthier adult population may result in lower economic costs associated with medical care and lost productivity.
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Advanced process monitoring using wavelets and non-linear principal component analysisFourie, Steven 12 January 2007 (has links)
The aim of this study was to propose a nonlinear multiscale principal component analysis (NLMSPCA) methodology for process monitoring and fault detection based upon multilevel wavelet decomposition and nonlinear principal component analysis via an input-training neural network. Prior to assessing the capabilities of the monitoring scheme on a nonlinear industrial process, the data is first pre-processed to remove heavy noise and significant spikes through wavelet thresholding. The thresholded wavelet coefficients are used to reconstruct the thresholded details and approximations. The significant details and approximations are used as the inputs for the linear and nonlinear PCA algorithms in order to construct detail and approximation conformance models. At the same time non-thresholded details and approximations are reconstructed and combined which are used in a similar way as that of the thresholded details and approximations to construct a combined conformance model to take account of noise and outliers. Performance monitoring charts with non-parametric control limits are then applied to identify the occurrence of non-conforming operation prior to interrogating differential contribution plots to help identify the potential source of the fault. A novel summary display is used to present the information contained in bivariate graphs in order to facilitate global visualization. Positive results were achieved. / Dissertation (M Eng (Control Engineering))--University of Pretoria, 2007. / Chemical Engineering / unrestricted
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Evaluating Multi-level Risk Factors for Malaria and Arboviral Infections in Regions of TanzaniaHomenauth, Esha January 2016 (has links)
Vector-borne diseases, such as those transmitted by mosquitoes, pose a significant public health concern in many countries worldwide. In this thesis, I explored the role of a number of risk factors defined at multiple scales on vector-borne disease prevalence, focusing on malaria and arboviral infections in several regions of North-Eastern Tanzania, with the principal aim of improving the overall diagnosis of febrile illness in this region.
First, I investigated the influence of household-wealth on prevalence of malaria and arboviral infections using principal component analysis (PCA), and then described the methodological challenges associated with this statistical technique when used to compute indices from smaller datasets. I then employed a multilevel modelling approach to simultaneously incorporate household-level anthropogenic factors and village-level environmental characteristics to investigate key determinants of Anopheles malaria vector density among rural households. These analyses provided methodologically rigorous approaches to studying vector-borne diseases at a very fine-scale and also have significant public health relevance as the research findings can assist in guiding policy decisions regarding surveillance efforts as well as inform where and when to prioritize interventions.
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Two-dimensional landmark analysis of Spinocyrtid brachiopods of Euramerica during the GivetianLayng, Alexander Patrick 01 August 2017 (has links)
Recent inquiry into the nomenclature of several species within Spinocyrtia has led to questions concerning name applicability and validity, particularly whether Delthyris granulosa and Spinocyrtia (Spirifer) granulosa are synonymous. This study utilized two-dimensional outline landmark analysis, a form of geometric morphometric analysis, to evaluate interspecific variation among these species. I took over a thousand photographs of over a hundred specimens of brachiopods belonging to the family Spinocyrtiidae. Ninety-six specimens originated from the Givetian outcrop belt of New York state, three were from northwestern Ohio, there was single Canadian specimen, and there was a single German specimen. The results from these analyses indicate that the mophospaces of Spinocyrtia (Spirifer) congesta, S. (Spirifer) granulosa, and S?. (Spirifer) marcyi are statistically (p < 0.05) distinct from one another.
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The Relationship between Education and Well-being in ChinaLiu, Sijia January 2020 (has links)
There are numerous approaches to quantitatively measure well-being. Most well-beingresearch are based on income or health situation from economics perspective. The needfor research on women’s relationship between education and well-being is an area thathas not been fully investigated. It is also important to know how the situation ofwomen’s well-being compare with men’s. The purpose of this research is to estimatewomen’s well-being and understand how well-being women is compared with men inChina. Different characteristics of men and women is considered and estimate thespecific relationship between education and well-being. Two measure of well-being areused: self-assessed unidimensional subjective well-being and parametrically estimatedmultidimensional well-being. Two measurement will help to understand the differencebetween subjectivity and objectivity of well-being. To achieve this goal, this researchcomputes and compares the well-being of 34,054 women and men by using ChineseGeneral Social Survey in 2012, 2013 and 2015. Well-being is measured by computingmultidimensionally by principal component analysis which depend on differentdomains of identity, capability, material well-being. All the domains contribute toindividual’s well-being. The findings suggest that, multidimensional well-being indexdiffer from the subjective well-being in ranking individual grouped by importantcommon characterizes. The difference is attributed to multidimensionality of the well-being index. Under this circumstance, education still does influence well-beingpositively conditional on controlling for identity, capability and material well-being.
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Detecting differences in gait initiation between older adult fallers and non-fallers through time-series principal component analysis (PCA)Yoshida, Kaya 04 January 2022 (has links)
Gait initiation (GI) is an important locomotor transition task that includes anticipatory postural adjustments and the joint propulsion necessary for the first step of walking. Metrics associated with this task are known to change across the lifespan and may provide valuable information for fall risk indication, as falls often occur during transitional tasks. Assessments of discrete variables between fallers and non-fallers at GI have provided insight into differences between groups. However, more complex approaches such as time-series principal component analysis (PCA) may allow the examination of changes in magnitude, pattern, and timing not detectable using discrete comparisons alone. Therefore, this thesis aims to characterize differences between fallers and non-fallers by examining the kinematics and kinetics of gait initiation using time-series PCA. A sample of 56 community-dwelling older adults was recruited for this study and completed five walking trials where GI was measured by two force platforms. PCA of centre of pressure kinematics and kinetics time-series data were used to identify the critical features of the signal, and multivariate analysis of covariance was used to compare the individual loading scores of each principal component for each phase between groups. It was revealed that fallers demonstrated differences in the range of mediolateral movement during weight transfer and forward progression, a greater range of anteroposterior movement in forward progression, and a more gradual rise in vertical forces in the first step, associated with a shorter first step length. These findings point to a tendency for fallers to prioritize stability over forward progression performance, and differences in postural control strategies, compared to non-fallers. Further, the use of time-series PCA helped to highlight differences not detectable using discrete analysis alone. / Graduate
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A Principal Component Algorithm for Feedforward Active Noise and Vibration ControlCabell, Randolph H. III 28 April 1998 (has links)
A principal component least mean square (PC-LMS) adaptive algorithm is described that has considerable benefits for large control systems used to implement feedforward control of single frequency disturbances. The algorithm is a transform domain version of the multichannel filtered-x LMS algorithm. The transformation corresponds to the principal components of the transfer function matrix between the sensors and actuators in a control system at a single frequency. The method is similar to other transform domain LMS algorithms because the transformation can be used to accelerate convergence when the control system is ill-conditioned. This ill-conditioning is due to actuator and sensor placement on a continuous structure. The principal component transformation rotates the control filter coefficient axes to a more convenient coordinate system where (1) independent convergence factors can be used on each coordinate to accelerate convergence, (2) insignificant control coordinates can be eliminated from the controller, and (3) coordinates that require excessive control effort can be eliminated from the controller. The resulting transform domain algorithm has lower computational requirements than the filtered-x LMS algorithm. The formulation of the algorithm given here applies only to single frequency control problems, and computation of the decoupling transforms requires an estimate of the transfer function matrix between control actuators and error sensors at the frequency of interest. The feasibility of the method was demonstrated in real-time noise control experiments involving 48 microphones and 12 control actuators mounted on a closed cylindrical shell. Convergence of the PC-LMS algorithm was more stable than the filtered-x LMS algorithm. In addition, the PC-LMS controller produced more noise reduction with less control effort than the filtered-x LMS controller in several tests. / Ph. D.
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Principal component analysis uncovers cytomegalovirus-associated NK cell activation in Ph+ leukemia patients treated with dasatinib / 主成分分析により明らかになったダサチニブ治療中のフィラデルフィア染色体陽性白血病患者におけるサイトメガロウイルス関連NK細胞の活性化Ishiyama, Ken-ichi 23 January 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20072号 / 医博第4165号 / 新制||医||1018(附属図書館) / 33188 / 京都大学大学院医学研究科医学専攻 / (主査)教授 前川 平, 教授 小川 誠司, 教授 小柳 義夫 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
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Machine Learning Driven Model Inversion Methodology To Detect Reniform Nematodes In CottonPalacharla, Pavan Kumar 09 December 2011 (has links)
Rotylenchulus reniformis is a nematode species affecting the cotton crop and quickly spreading throughout the southeastern United States. Effective use of nematicides at a variable rate is the only economic counter measure. It requires the intraield variable nematode population, which in turn depends on the collection of soil samples from the field and analyzing them in the laboratory. This process is economically prohibitive. Hence estimating the nematode infestation on the cotton crop using remote sensing and machine learning techniques which are cost and time effective is the motivation for this study. In the current research, the concept of multi-temporal remote sensing has been implemented in order to design a robust and generalized Nematode detection regression model. Finally, a user friendly web-service is created which is gives trustworthy results for the given input data and thereby reducing the nematode infestation in the crop and their expenses on nematicides.
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The Objective Assessment of Movement Quality Using Motion Capture and Machine LearningRoss, Gwyneth Butler 05 January 2022 (has links)
Background: Movement screens are frequently used to identify abnormal movement patterns that may increase risk of injury and/or hinder performance. However, abnormal patterns are often detected visually based on the observations of a coach or clinician leading to poor inter- and intrarater reliability. In addition, they have been criticized for having poor validity and sensitivity. Quantitative, or data-driven methods can increase objectivity, remove issues related to inter-rater reliability and offer the potential to detect new and important features that may not be observable by the human eye. The combination of motion capture data, pattern recognition and machine learning could provide a quantitative method to better assess movement competency.
Purpose: The purpose of this doctoral thesis was to create the foundation for the development of an objective movement screening tool that combines motion capture data, pattern recognition and machine learning. This doctoral thesis is part of a larger project to bring an objective movement screening tool for use in the field to market.
Methods: This thesis is comprised of four studies based on a single data collection and a common series of pre-processing steps. Data from 542 athletes were collected by Motus Global, a for-profit biomechanics company, with athletes ranging in competition level from youth to professional and competing in a wide-range of sports. For the first study of this thesis, an online software program was developed to examine the inter- and intra-reliability of a movement screen, with intrareliability being further examined to compare reliability when body-shape was and was not modified. The second study developed the objective movement screen framework that utilized motion capture, pattern recognition and machine learning. Study 3 and 4 assessed different types of input data, classification goals (e.g., skill level and sport played), feature reduction and selection methods, and increasingly complex machine learning algorithms.
Results: For Study 1, when looking at inter- and intra-rater reliability of expert assessors during subjective scoring of movements, intra-rater reliability was better than inter-rater reliability. When assessing the effects of body-shape, on average, reliability worsened when body-shape was manipulated. Study 2 provided proof-of-principle that athletes were able to be classified based on skill level using marker-based optical motion capture data, principal component analysis (PCA) and linear discriminant analysis. For Study 3, PCA in combination with linear classifiers outperformed non-linear classifiers when classifying athletes based on skill level; feature selection increased classification rates, and classification rates when using simulated inertial measurement unit data as the input data were on average better than when using marker-based optical motion capture data. In Study 4, athletes were able to be differentiated based on sport played and recurrent neural nets (RNNs) and PCA in combination with traditional linear classifiers were the optimal machine learning algorithms when classifying athletes based on skill level and sport played.
Conclusion: This thesis demonstrates that objective methods can differentiate athletes based on desired demographics using motion capture, pattern recognition and machine learning. This thesis is part of a larger project to bring an objective movement screening tool for field-use to market and provides a solid foundation to use in the continued development of an objective movement screening tool.
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