2021 UMKC Theses - Freely Available Online
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Item Comparative Analysis of Marine Diatom Species Richness and Diversity Across the Paleocene-Eocene Thermal Maximum at Different Latitudes(2022) Hentzen, Anne; Davies, Caroline P., 1961-This study examines the impacts of rapid warming experienced during the Paleocene-Eocene Thermal Maximum (PETM) at approximately 56 Ma on marine diatom communities and how these effects differ based on latitude. Understanding how diatom communities have responded to rapid warming events like the PETM may provide insight into how diatom communities will be impacted by the changes occurring as a result of the current global climate change, and the potential changes to the carbon cycle and marine primary production that may result from these changes. There are differing views of whether these changes will lead to a positive or negative feedbacks in the global carbon cycle. Potential changes are assessed using statistical analyses of diatom abundance data from existing marine sediment cores from the Lomonosov Ridge, in the Central Arctic Ocean, the Blake Nose, in western North Atlantic Ocean, and the Broken Ridge in the Eastern Indian Ocean. Cluster analysis and Principal Component Analysis are performed to identify variance between datasets. Abundance data is not measured consistently at all locations, complicating comparisons between datasets. There is some evidence that diagenesis has limited diatoms preservation during the PETM in some locations. Impacts on diatom communities are assessed using species richness and species diversity calculated using the Shannon-Wiener Diversity Index. Changes observed in diatom species are assessed for a more comprehensive picture of how rapid warming impacted diatom species richness and diversity across the globe. The results of this study suggest that diatom communities were negatively affected by the rapid warming characteristic of the PETM in middle latitude locations, while the Central Arctic Ocean diatom communities showed an increase in diatom species richness and diversity. The diatom community response to rapid warming observed in the Central Arctic Ocean across the PETM may be connected to poor diatom preservation prior to the PETM or the vastly different paleogeography providing increased nutrient availability from runoff in the Central Arctic Ocean. If marine diatom communities suffer as the data suggests in middle latitude locations, then it is likely decreases in diatom species diversity and richness have the potential to lead to a positive feedback loop for further warming. However, more data is needed in high latitude locations to determine if the negative effects of rapid warming are specific to middle latitude locations.Item Physical activity in adolescents: an expanded theory of planned behavior approach with interaction effects(2021) Nelson, Samuel Christopher; Ha, Oh-RyeongObesity in adolescents in the United States has increased at an alarming rate over the past decade, with concerns related to the issue centered around a lifetime of greater prevalence of poor health outcomes for these individuals. Staying active and participating in daily physical activity is one of the key ways adolescents can prevent the onset of obesity early in life and increase physical and mental well-being, despite weight status. As physical activity plays a critical role in the prevention of poor physical and mental health outcomes in adolescents, it is important to understand what factors contribute to a teen’s decision to participate in physical activity. One way researchers have historically tried to understand complex decisions is through the use of psychological models. This study uses the Theory of Planned Behavior model, a model commonly used to examine decisions in the health field, to define and explore important factors contributing to physical activity in adolescents or a lack thereof. Additionally, this study expanded the Theory of Planned Behavior model to explore additional relationships among variables in the model and those impacts on physical activity in adolescents. This study uses data collected by the National Cancer Institute for The Family Life, Activity, Sun, Health, and Eating (FLASHE) study. The data from 1379 individuals was retained for the study. Participants completed up to three surveys pertaining to demographic information, information about diet, and information about physical activity. Results indicated that the original Theory of Planned Behavior Model did not fit the data well. Factors like attitude toward physical activity and perceived behavioral control over one’s ability to engage in physical activity were significant; however, the overall model did not accurately explain variations in physical activity. This may be attributed to the unique developmental and environmental circumstances of adolescents compared to the adult population for whom the model was postulated. Results also indicated a significant improvement in the model’s ability to explain adolescent physical activity when factors were allowed to covary. Further analysis showed a significant interaction effect between perceived behavioral control and subjective norms on behavioral intent. Results are contextualized and discussed in relation to contributions to research of factors involved adolescent physical activity. Study limitations and future research directions are also discussed.Item Optic nerve subarachnoid space cerebral spinal fluid computational fluid dynamics(2021) Kent, Vincent Levi Ryan; Mehdizadeh, AmirfarhangCerebral spinal fluid (CSF) is driven throughout the subarachnoid space (SAS) and serves a variety of crucial functions. The behavior of CSF within the optic nerve subarachnoid space (ONSAS) has special interest because it is relatively unknown. Additionally, the effects of improper flow characteristics of CSF within the ONSAS could be a contributing factor to optical neuropathies such as glaucoma. Rendering a three-dimensional model of the optic nerve (ON) and associated SAS can help provide a better representation of the physical boundary conditions that influence CSF flow. Utilizing this model, computational fluid dynamics (CFD) of the CSF within the ONSAS can be conducted to provide a visualization of the CSF behavior. In addition, flow rate and velocity of the ONSAS CSF can be calculated. Determination of the healthy velocity and volumetric flow rate of CSF within the ONSAS could help doctors to estimate ICP without utilizing invasive procedures such as lumbar puncture. The understanding of this flow within the ONSAS could provide medical professionals with more information prior to proceeding with invasive procedures and diagnosis of optic neuropathies. As a result, this study aims to establish a procedure for simulating the CSF flow within the ONSAS and determination of CSF velocity and volumetric flow rate.Item Self-Controlled Food and Leisure Activity Decision-Making(2021) Bailey, Carrie; Lim, Seung-LarkThe experiment aimed to examine the effects of stress, coping, weight status, age, and attribute weightiness on health decision-making in females and males. Participants completed an online experiment consisting of self-reports, attribute rating tasks, and mouse-tracking choice tasks. Stress, coping, and weight status were obtained from self-reports. The food rating task consisted of rating a series of foods on taste, health, and liking. The activity rating task consisted of rating a series of leisure activities on enjoyment, health, and liking. Mouse- tracking choice tasks consist of choosing to eat or not eat foods and do or not do activities. There were significant gender differences in attribute decision weights on preference – females showed higher taste and enjoyments attribute decision weights compared to males after controlling for age. In females, food self-control was associated with engagement coping and health attribute decision weight. In males, food self-control was associated with stress and health attribute decision weight. In both females and males, activity self-control was associated with solely by enjoyment attribute decision weight. Overall, the importance of health attributes on preference was associated with self-controlled food decisions, while the importance of enjoyment attributes on preference was associated with self-controlled activity decisions.Item Assessment of genetic algorithm based assignment strategies for unmanned systems using the multiple traveling salesman problem with moving targets(2021) Smith, Cody Dakoi; Fields, TravisThe continuous and rapid advancements in autonomous unmanned systems technologies presents increasingly sophisticated threats to military operations. These threats necessitate the prioritization of improved strategies for military resources and air base defense. In many scenarios, it is necessary to combat hostile unmanned systems before they reach the defensible perimeters of existing fixed-base defense systems. One solution to this problem is weaponizing friendly unmanned systems to hunt and kill hostile unmanned systems. However, the assignment and path planning of these “Hunter-Killer” systems to incoming hostile unmanned systems, in a multiple friendly versus multiple enemy scenario, presents a major challenge and can be represented by the Multiple Traveling Salesmen Problem with Moving Targets (MTSPMT). The MTSPMT is a combinatorial optimization problem and an extension of the classical Traveling Salesman Problem whereby the number of salesmen is increased and targets (cities) move with respect to time. The objective of the MTSPMT, for the application of military defense using a squadron of Hunter-Killer unmanned systems, is to determine a path that minimizes the cost required for multiple Hunter-Killer unmanned systems to successfully intercept all incoming threats. In this study, an assessment of genetic algorithm based assignment strategies for unmanned systems using the MTSPMT is performed. A number of scenarios were constructed using up to 50 hostile unmanned systems and the generated solutions were compared based on their resulting time to converge, solution fitness, and number of generations required. Findings indicate that under certain conditions genetic based algorithms provide better results on average and converge more rapidly than brute force searching and existing assignment and path planning solutions.