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X-Ray Particle Image Velocimetry In 3D-Printed Phantoms Using High-Speed Angiography
No full textM.S.The details of blood flow pattern and velocity can provide useful information for doctors to decide whether to treat the diseased vessels and evaluate the therapeutic effect. It is hard to see these blood flow details using "real-time" imaging at 10 to 30 frames per second. High-speed angiography (HSA) provides the time resolution needed to record the details of blood flow in the blood vessels of patients. Xcounter's Actaeon detector is capable of x-ray imaging at 1000 fps, providing enough time and spatial resolution to quantify details. A new method to obtain the blood flow details of patients' specific geometry through experiments shows a combination of cross-correlation and optical flow methods to find the velocity of the microsphere contrast particles at 1000 fps. Microspheres were prepared by immersing them in iodine contrast media to provide radiopaque opacity and injected during x-ray irradiation into a 3D printed patient specific vascular model. Actaeon's high sensitivity mode captures images at 1000 frames per second for 2.4 seconds and thus provides quantitative data about the flow details in a vascular model and qualitative information about the flow at different time points during the collection period. This method can realize the new measurement of blood flow characteristics in specific vascular systems of patients. Validating the accuracy of this method was conducted by generating an image sequence with a microsphere with known displacement and velocity.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
An Integrative Assessment of the Pattern and Causes of Bilateral Asymmetry Across the Human Skeleton
No full textPh.D.In humans, the musculoskeletal system is programmed to grow symmetrically, however a wide variety of genetic and environmental stressors can interrupt its ontogenetic development, causing asymmetrical variation. There are several different classes of asymmetry, but the three forms considered here are fluctuating asymmetry (FA) (random deviations of either the right or left side of the body across a population), directional asymmetry (DA) (when one side of the body is consistently larger across a population), and individual asymmetry (IA) (pattern of asymmetry at the individual level). Previous studies have shown that asymmetry can be caused by a multitude of factors including poor nutrition, inbreeding, or biomechanical loading; however, these studies have offered confounding interpretations as they approach the potential causes of asymmetry using different a priori theoretical assumptions. Furthermore, past studies tend to focus on a single region of the body, thereby limiting the ability to understand the true source(s) of asymmetry in a coordinated manner. This dissertation addresses these shortcomings by testing a series of inter-related research hypotheses centered on patterns of fluctuating and directional asymmetry in the 3D morphology of the cranium, mandible, sacrum, os coxa, femur, tibia, humerus, and radius from a sample of 123 modern human skeletons of known age and sex, and from across three secular groups. Specifically, the null hypothesis was that all skeletal regions would display similar levels and patterns of asymmetry across the entire sample. In essence, this prediction supposes that if an individual were inherently asymmetrical due to genetic or environmental factors it would affect their entire skeleton in a coordinated manner. If this null prediction were rejected then three alternative explanations were explored; that asymmetry patterns are related to (i) the lateralization of the upper limb, (ii) developmental timing of bone formation, or (iii) evidence of generalized childhood stress. In regard to the primary null hypothesis, the results found no significant correlations in patterns of FA between any of the bones for either sex, indicating that different skeletal regions do exhibit different patterns of asymmetry...**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Capturing the Lived Experiences of Refugee Families: A Positioning, Literacies, and Multimodal Perspectives Study
No full textPh.D.Prior research has revealed that the number of refugee individuals and families moving to the United States significantly increased between 1980 and 2016. Even though the number of incoming refugees declined in 2017 due to U.S. government policy changes, this decline did not influence the size of the existing population base. Due to the differences between the United States and their countries of origin, most students and families experience various kinds of challenges within an unfamiliar educational system and everyday life. Additionally, the students' funds of knowledge and family strengths are not easily recognized in American formal educational settings. Not only do the students struggle with school learning during their resettlement in the United States, but teachers also need help to prepare for working with the students. A deeper understanding of the lived experiences of these families will support the students in expressing their voices and also help educators understand and advocate for the students. Drawing on positioning theory, literacy as a social practice, and the social semiotics multimodal perspective, this qualitative study aims to explore the lived experiences of three refugee families in the United States, particularly with regard to education, language, literacy, and culture. Ethnographic and narrative methods are utilized to support data collection and analysis. Data sources include audio and video recordings of family conversations, interviews with parents, artifacts provided by the participants, and the researcher's post-data-collection reflective notes. Data analysis generated three major themes bounded with times and spaces: the participants' past experiences across global contexts, the participants' current experiences in the United States, and the participants' expectations and imagined selves within future orientations. Findings present (1) the ways that participants position themselves and their family members within these three themes, (2) the ways that the children make representational meaning of their lived experiences related to the three themes during multimodal-storybooks-making processes, and (3) the ways that the children and parents engaged with literacies in Burmese and English in multiple contexts. Findings highlight that the participants were positioned as experts who could strategically mobilize social, cultural, linguistic, and literacy resources in global contexts; these positions debunked the myths that refugee families are deficit resources that can aid them in navigating dominant discourses. Implications include the following: refugee children's family identities and literacies that are situated in transnational contexts should be acknowledged and valued by educators in formal educational settings; refugee children should be encouraged to author their own storybooks, exercise their agencies, and collaborate with their peers for meaning-making through multiple modes; refugee parents' voices should be heard, and the parents should be encouraged to be involved in their children's learning in multiple ways. This dissertation work also calls for further research on various methods to advocate and empower the voices of refugee students and families.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Public Opinion of Health Care Systems: Social Determinants and the Moderating Effects of Social and Historical Contexts
No full textPh.D.The health care system in the U.S consumes over 17% of the nation's gross domestic product, which is more than $2.7 trillion and there are over 16 million people working for the system. Still, Americans' health status is worse than their peers in seven other developed countries (the U.K., Germany, Sweden, Canada, France, Australia, and Japan), as measured by life expectancy at birth and infant mortality rate. Although we have a good understanding of the structural characteristics of the U.S. health care system which differentiate it from the health care systems in other countries, what we know less about is the effects of the configuration of health care system on public satisfaction and population health and how the changes in economy affect public support for government intervention in health care. In my dissertation, I use multilevel models to explore individual and between-country differences in public opinion on health care and its implications for medical profession in 31 countries, and the age-period-cohort effects on public attitude toward government role in health care in the U.S. In chapter one, I investigated the relationship between individual socio-economic characteristics with general satisfaction with the health care system as well as the effects of the macro-level variables including the financing configuration of the health care system and the percentage of aging population. Chapter two extends the framework in the first paper from my dissertation by looking at the relationship between individual socio-economic characteristics and trust in physicians as well as that between the country-level institutional set-up of health care systems (i.e. different types of health care system) and public trust in physicians. Chapter three employs hierarchical age-period-cohort models and binary logistic models to investigate the change of public attitudes toward government intervention in health care from 1986 to 2018 in the United States.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
On the Maximum Extent of the Greenland Ice Sheet in Southwestern Greenland During the LGM
No full textM.S.Whether the weathered, mountain summits adjacent to southwestern Greenland's coast were ice covered during the Last Glacial Maximum (LGM; ~20,000 years ago) is debated. Traditionally, the boundary between high-elevation, weathered surfaces and lower-elevation glacially sculpted surfaces has been interpreted as the upper ice limit of the Greenland Ice Sheet (GrIS) during the LGM. There is recent evidence, however, that thin, cold-based ice frozen to the bed can cover and preserve these types of weathered surfaces. A thicker LGM ice sheet in southwestern Greenland would be more consistent with the high marine limits reported in the area. I hypothesize that the high-elevation surfaces near Sisimiut, southwest Greenland, were covered by the GrIS during the LGM. I tested this hypothesis by dating high-elevation bedrock and nearby glacial erratics with cosmogenic 10Be, 26Al and 14C exposure dating. I also investigated if the margin of the GrIS extended farther onto the continental shelf than is currently mapped using an empirical relationship between the marine limit and their distant from the LGM ice sheet margin. Finally, I developed a new 2D Greenland Ice Sheet model to quantitatively compare generated RSL curves using different ice sheet extents to actual sea level curve data from the region. Collectively, this work shows that the GrIS was thicker and extended farther off the coast of southwestern Greenland during the LGM than is currently depicted in the literature. The greater ice sheet thickness in southwestern Greenland implies that a larger volume of ice melted after the LGM at a higher rate than previously estimated.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
The Investigation of Disease States Through Omics Based Techniques by Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry
No full textPh.D.The study of –omics has rapidly gained momentum since its beginning with the advent of the Human Genome Project. As the human genome has been unraveled, studies of the downstream pathways have spurred from the resulting knowledge. Mutated genes have been found that change the directions for the creation of proteins, changing amino acid sequences, and in some instances causing its malfunction. With the protein no longer working properly, small molecules are produced in excess or inadequately for the body's needs. These changes can be seen throughout the body, from the tissue itself to biological fluids. The main objective of this thesis was to investigate biomarkers for multiple disease states using both -omics-based approaches in tandem with high resolution mass spectrometry. This work specifically focuses on (1) the validation of stercobilin as a putative biomarker for autism spectrum disorders across multiple murine models, (2) the sequencing of glucokinase, a protein hypothesized to play key roles in diabetes, to initiate the analysis of active binding sites, (3) the observation of lipid changes within an animal model of primary demyelination, mimicking both traumatic spinal cord injury and multiple sclerosis, to determine lipids which play a key role in the myelination process, and (4) the observation of neuropeptides within the brains of rats for their use in the study of drug addiction, specifically cocaine. The utilization of mass spectrometry to study biomolecules has become a golden standard owing to the introduction of two different ionization techniques, electrospray ionization (ESI) and matrix assisted desorption ionization (MALDI). The first two aims will discuss the utilization of ESI techniques for the study of small molecules, proteins, and peptides. Although the first aim will touch upon the use of MALDI for small molecule analysis, its utilization in the rapidly growing field of mass spectrometry imaging will be discussed within aims three and four to study lipids, and peptides.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Time Constrained UAV Path Planning in 3D Network For Maximum Information Gain
No full textM.S.Our focus is on the development of a UAV path to maximize the collected amount of information from the AO within a specified fuel limit. Different regions of the AO have different monitoring requirements, achieved through visitation at an appropriate altitude. A MIP formulation is developed to solve the path planning problem when the UAV turning radius is not factored in. Once the path has been identified, turning radius considerations are introduced and optimized using another MIP formulation. Furthermore, a simulated annealing heuristic is developed to solve large problems where the MIP approach is not feasible. Through computational testing we verify that the heuristic generates acceptable results in terms of solution quality (when compared to the exact MIP method) for small to medium size problems, and further, verify that it generates results for large problems in acceptable computational time. We empirically test the impact of the fuel limit on the information gained. We explore two methods for increased information gain, using a single UAV with a higher fuel capacity or multiple UAVs with lower fuel capacity. This analysis is aimed to aid in decision making of the number of UAVs to be deployed and model type selection for military operations.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
A Typology, Analysis, and Interpretation of Ground Stone Tools from Çatalhöyük West Mound: Food Processing and Craft Production Tools in the Late Neolithic to Early Chalcolithic of Central Anatolia
No full textPh.D.The Early Chalcolithic site of Çatalhöyük West has become increasingly well studied over the past 15 years. This project examines the ground stone tools from the West Mound, an artifact type that holds much potential but has been historically understudied in archaeology. For this research, I studied 774 ground stone objects recovered from various West Mound contexts with an emphasis on Trench 5, the most extensive excavation area on the mound. In this dissertation, I present petrographic analysis of the raw materials used for ground stone manufacture and a typology developed to categorize types of tools. I conducted a variety of distribution analyses to explore the interactions between rock types and tool types. I propose potential explanations for the differential usage of andesites and basalts and the differential fragmentation patterns for grinding slabs and grinding handstones. Finally, I present evidence of the possibility of early specialization in tool production.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Video Games and The Museum - A Critical Analysis
No full textM.A.The aim of this thesis is to critically analyze the methodologies of preservation, display, contextualization, and interpretation of video games in context to the museum. Video games are a multilayered medium which encompass interactivity, immersion, technology, play, history, art, and are intrinsically tied to a larger narrative of socio-cultural representation in digital form. We will go over the "how" and "why" video games have been represented in different types of museums, such as play museums, video game museums, art museums, media museums, history museums, galleries, and virtual spaces. The Strong National Museum of Play will be used as case study to further the analysis. Not only are there different methodologies of display, preservation, and interpretation of games in various museums, but games have also influenced exhibition design and audience engagement through the process of gamification. Furthermore, we will explore the audience in the museum and how different marketing strategies can increase visitation, alter perceptions of the museum, and engage in community outreach.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
New Methods in Optimization Algorithms and Technology Applied to VMAT and IMRT Inverse Treatment Planning
No full textPh.D.A TPS produces IMRT and VMAT plans by applying an optimization process to an objective function, followed by an accurate calculation of the final, deliverable dose. We developed two novel methods to optimize these plans. The first method involves using Monte Carlo (MC) routines. MC is considered to be the gold standard of dose calculation due to its high accuracy; however, it is currently too slow for practical comprehensive VMAT optimization. Instead, we developed an approach called enhanced optimization (EO), which employs the TPS VMAT plan as a starting point, and applies small perturbations, called beamlets, which are calculated using MC, to nudge the solution closer to a true objective minimum. A significant framework was developed in order to efficiently run parallelized MC simulations. The second method involves optimization of IMRT plans using new computer hardware: the Hamiltonian Engine for Radiotherapy Optimization (HERO). For both proposed novel methods, DICOM files for clinical VMAT plans files are exported from the TPS and used to generate input files for the EGSnrc MC toolkit or the HERO. For EO, a simple greedy search algorithm is applied to minimize the objective function, and the resulting modified control point parameters are imported into the TPS to calculate the final, deliverable dose, and to compare the EO plan with the original. EO produced improved objective scores (by 6% to 60%) and DVH's for the brain plans and the head and neck plans. Although EO also reduced the objective scores for the prostate plans (by 46% and 79%), their absolute score and DVH improvements were not substantial. Further development will reduce the EO beamlet computation time and result in more sophisticated EO treatment planning methods. The HERO was able to quickly (under 45 seconds each) find solutions to seven prostate IMRT plans and produced objective scores 93.8% to 99.3% lower than the TPS objective scores. In the future, these novel methods will be useful clinically in finding more optimal solutions to IMRT and VMAT optimization problems.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*