Electronic Thesis or Dissertation

Much of Interior Alaska contains permafrost, which is a permanently frozen layer found within or at the surface of the Earth. Historically, this permafrost has experienced relative stability, with limited thaw during warmer summer months and fire events. However, largely due to the impact of a warming climate, among other factors, permafrost that would typically experience limited thawing during the summer season has recently been thawing at an unprecedented rate. Trapped by this layer of permafrost is a large quantity of carbon (C), which could be released into the atmosphere as greenhouse gases such as carbon dioxide (CO2) and methane (CH4). Due to the remoteness of the Arctic, there is a lack of yearly recorded permafrost thaw depth and snow depth values across much of the region. As such, the focus of this research was to establish a framework to identify how permafrost thaw depth and snow depth can be predicted across both a 1 km2 local scale and a 100 km2 regional scale in Interior Alaska by a combination of 1 m2 field data, airborne and spaceborne remote sensing products, and object-based machine learning techniques from 2014 – 2022. Machine learning techniques Random Forest, Support Vector Machine, k-Nearest Neighbor, Multiple Linear Regression, and Ensemble Analysis were applied to predict the permafrost thaw depth and snow depth. Results indicated that this methodology was able to successfully upscale both the 1 m2 field permafrost thaw depth and snow depth data to a 1 km2 local scale before successfully further upscaling the estimated results to a 100 km2 regional scale, while also linking the estimated values with ecotypes. The best results were produced by Ensemble Analysis, which tended to have the highest Pearson’s Correlation Coefficient, alongside the lowest Mean Absolute Error and Root Mean Square Error. Both Random Forest and k-Nearest Neighbor also provided encouraging results. The presence or absence of a thick canopy cover was strongly connected with thaw depth and snow depth estimates. Image resolution was an important factor when upscaling field data to the local scale, however it was overall less critical for further upscaling to the regional scale.

This study examines whether emerging growth company (EGC) investors respond to the annual required internal control disclosures over financial reporting (ICFR). I develop three hypotheses to test across the EGC lifecycle. Specifically, I investigate whether the first year ICFR disclosure, the remediation of a previously reported material weakness ICFR disclosure and the EGC exit are associated with the firm’s cumulative abnormal return over a three-day event window. Prior literature has observed that ICFR disclosures by management and the ICFR audit opinion can be shown to be informative to investors. However, I am not aware of any study investigating whether the EGC investors respond to this type of information. I find that the reported ICFR disclosures are not associated with cumulative abnormal returns during their initial ICFR report disclosure or upon exit as informative but do respond to the reporting of material weakness remediation.

In today’s world, data is generated at an unprecedented rate, and a significant portion of it is unstructured text data. The recent advancements in Natural Language Processing have enabled computers to understand and interpret human language. Data mining techniques were once unable to use text data due to the high dimensionality of text processing models. This limitation was overcome with the ability to represent data as text. This thesis aims to compare the predictive performance of structured versus unstructured text data in two different applications. The first application is in the field of real estate. We compare the performance of tabular real-estate data and unstructured text descriptions of homes to predict the house price. The second application is in translating Electronic Health Records (EHR) tabular data to text data for survival classification of COVID-19 patients. Lastly, we present a range of strategies and perspectives for future research.

The goal of this study is to determine how negative information affects purchasing decisions and what neurological processes are included in these purchasing decisions. Specifically, this study aims to explore the effect of consumers receiving the same negative attribute twice versus two different negative attributes for a product. The introduction of this study will discuss background concepts like the Controlled Semantic Cognition Framework from Lambon Ralph et al., (2017) and the neural processes behind selection as discussed in Thompson-Schill et al., (1997). The results indicated that there were differences in hemodynamic response between conditions where the same negative attribute was presented with a product twice versus conditions where two different negative attributes were presented with a product. Both behaviorally and hemodynamically, the results provide evidence supporting an inner conflict when dealing with two negative alternative choices. Future research could include realistic advertisements to better mimic everyday scenarios.

Prior research on neurophysiology of infants of depressed mothers commonly has focused on EEG power and asymmetry. Whether infants of depressed mothers show differences in coherence is undetermined. This study examined the development of EEG alpha coherence in infants of mothers with various degrees of depression. Also investigated was the normative development of alpha coherence in infancy. The relationship between maternal depression and infant coherence was analyzed at different infant ages, from 1-12-months-old. There were significant effects of maternal depression on infant coherence between frontal-occipital regions, frontal-parietal regions, and central-parietal regions, in 1-month-olds. There were also significant maternal depression effects in central-parietal coherence in 1-3-month-olds and 3-6-month-olds. Differences were in the right hemisphere and were generally characterized by lower coherence in infants whose mothers had higher depression. Infants whose mothers had lower depression demonstrated age-related decreases in coherence, but infants of more highly depressed mothers did not show age-related differences.

The purpose was to study the results Professional Certified Nurse Coaches (PCNCs) potentially have in mutually patterning the human energy field toward a higher wave frequency pattern of power as measured by the power as knowing participation in change tool and reflected in the narrative pattern profiles obtained from in-depth interviews. Participants were nurses working during the COVID-19 pandemic. Using Barrett’s (1986, 2020) power as knowing participation in change theory an explanatory convergent parallel mixed method using a single group with repeated measures (pre/post) and qualitative directed content analysis was used. A method for apprehending pandimensional awareness of unity and a mutual rhythmic-frequency process of-analysis-synthesis and were developed for the synthesis of numeric and textual data within a unitary perspective. Findings included a statistically significant effect for the total and four interrelated dimensions with a large effect size, except for the dimension involvement, which had a medium effect size. The results were the same when controlling for years of experience indicating that regardless of years of experience, professional nurse coaching appears to be beneficial. Six essences were identified and articulated as a group, as individuals, and across time. Joint displays show the synthesis. These findings have implications for nursing research, caring sciences, nursing education, nursing practice, policy, and professional nurse coaching.

While the thalamus and hippocampus are generally understood to contribute to mammalian spatial navigation, the degree to which thalamic input contributes to representations of space during navigation remains unclear. Specifically, anterior dorsal thalamic nuclei (ADN) provide a relational or directional framework known as the head direction (HD) network, which is hypothesized to play a significant role in guiding hippocampal-dependent navigation. The current study focuses on the contribution of the ADN to direction and place-dependent spatial navigation in adult male C57BL6J mice. An inhibitory chemogenetic (hM4Di) receptor was bilaterally expressed in the ADN after viral stereotaxic injection. Mice were trained in a spatially focused task, the Morris water maze (MWM), and after systemic administration of the hM4Di agonist, clozapine-Noxide (CNO) at 5mg/kg, demonstrated equivalent preference for using directional or place-based search behavior. These results suggest that the selective silencing of ADN at 5mg/kg CNO does not negatively affect spatial navigation in mice.

The goal of this dissertation is to estimate the precise asymptotics for the number of geometric equivalence classes of Morse functions on the 2-sphere. Our approach involves utilizing the Lagrange inversion formula, Cauchy’s coefficient formula, and the saddle point method for the asymptotic analysis of contour integrals to analyze the generating function derived by L. Nicolaescu, expressed as the inverse of an elliptic integral. We utilize complex analysis, nonlinear functional analysis in infinite sequence spaces, and interval arithmetic to write all the necessary MATLAB programs that validate our results. This work answers questions posed by Arnold and Nicolaescu, furthering our understanding of the topological properties of Morse functions on two-dimensional manifolds. It also demonstrates the effectiveness of a computer assisted approach for asymptotic analysis.

Sickle Cell Disease (SCD) is a genetic disease that affects approximately 100,000 people in the USA and millions worldwide. The disease is defined by a mutation in hemoglobin, the red blood cell’s oxygen carrying component. Under hypoxic (low oxygen) conditions, the mutated hemoglobin (known as HbS) polymerizes into rigid fibers that stretch the cell into a sickle shape. These rigid cells can occlude blood vessels and cause an individual immense pain. Currently, no point-of-care devices exist in the market for assisting those with SCD. Using microfluidics with custom designed portable impedance measuring hardware we can achieve label-free in vitro analyses of SCD rheology.
This dissertation presents two impedance-based devices for finger-prick volume blood testing, including a microflow cytometer for SCD diagnostics and a vaso-occlusion tester for monitoring blood flow activities. First, the microflow cytometer is validated by measuring the electrical impedance of individual cells flowing through a narrow microfluidic channel. Cellular impedance is interpreted by changes in subcellular components due to oxygen association-dissociation of hemoglobin, using an equivalent circuit model and Multiphysics simulation. Impedance values of sickle cells exhibit remarkable deviations from normal blood cells. Such deviation is quantified by a conformity score, which allows for measurement of SCD heterogeneity, and potentially disease severity. Findings from this study demonstrate the potential for SCD screening via electrical impedance. Second, a vaso-occlusion tester is validated by measuring the impedance response of blood flow within a microfluidic mimic of capillary bed.

This study examines post-processual, critical theory, and decolonial perspectives applied to archaeology to establish an alternative practice that here is termed “arqueología comprometida” (committed archaeology). Considering the history of archeology in Latin America, its current context and the logic of archaeological practice, the objective of this contribution is not only to offer an assessment of the processes of making history, but to also provide a collaborative study relevant to both decolonial and public archaeology. The study is carried out in the Comuna Ancestral Valdivia (Ancestral Commune of Valdivia) (ACV), located in the province of Santa Elena, on the Ecuadorian coast. Historical analyses are structured to be critically evaluated from a decolonial perspective in order to characterize archaeology and to understand its wider and less obvious influence on societies. The alternative way of doing archeology proposed in this study incorporates the achievements and memories of local comuna members into the official history of the site and to establish a project focused on the material development of the local museum. In summary, this is an ethical and epistemological reflection of archaeological practice using anthropological methods to think through and propose a public archeology project that can be relevant and useful for people historically affected by colonial legacies in Latin America.