Digital Commons Network^™

All-Optical Probes Of Particle-Like Charge Migration Dynamics, Kyle A. Hamer

LSU Doctoral Dissertations

Particle-like charge migration (CM) is the coherent, back-and-forth motion of a positively-charged electron hole along the backbone of a molecule following a sudden ionization. CM in small molecules generally occurs on an Angstrom (10^-10 m) spatial scale and an attosecond (10^-18 s) timescale. I use time-dependent density-functional theory (TDDFT) to simulate CM modes in organic molecules, and to explore all-optical probes of this attosecond electron dynamics using high-harmonic spectroscopy (HHS). By leveraging my results from previous studies of two-center interferences in carbon dichalcogens, in which I separated the harmonic signal into contributions from individual Kohn-Sham orbitals, I first …

Post-Modeling Adjustments And Delivered Dose Verification Of The 6fff Beam Model Commissioned For The Monaco Treatment Planning System, Grant C. Debevec

LSU Master's Theses

External beam radiation therapy has been shown to be an effective treatment method for tumors and abnormalities of the spine and vertebral region. Treating the spine using a stereotactic body radiation therapy (SBRT) technique can reduce toxicity to the spinal cord. The 6 MV flattening filter free (6FFF) beam model is currently used to plan and calculate dose for SBRT treatment plans, and the treatment plans are delivered using a linear accelerator (LINAC).

The commissioned beam model represents an invariant component of a LINAC. For volumetric modulated arc therapy (VMAT) treatment plans, the multileaf collimator (MLC) positions are changing throughout …

Gut Microbial Dysbiosis Differs In Two Distinct Cachectic Tumor-Bearing Models Consuming The Same Diet, Lauri O. Byerley, Brittany Lorenzen, Hsiao Man Chang, William G. Hartman, Michael J. Keenan, Ryan Page, Meng Luo, Scot E. Dowd, Christopher M. Taylor

Faculty Publications

The impact of cancer cachexia on the colonic microbiota is poorly characterized. This study assessed the effect of two cachectic-producing tumor types on the gut microbiota to determine if a similar dysbiosis could be found. In addition, it was determined if a diet containing an immunonutrient-rich food (walnuts) known to promote the growth of probiotic bacteria in the colon could alter the dysbiosis and slow cachexia. Male Fisher 344 rats were randomly assigned to a semi-purified diet with or without walnuts. Then, within each diet group, rats were further assigned randomly to a treatment group: tumor-bearing ad libitum fed (TB), …

Improved Tensor Current Limit From B 8 Β Decay Including New Recoil-Order Calculations, B. Longfellow, A. T. Gallant, G. H. Sargsyan, M. T. Burkey, T. Y. Hirsh, G. Savard, N. D. Scielzo, L. Varriano, M. Brodeur, D. P. Burdette, J. A. Clark, D. Lascar, K. D. Launey, P. Mueller, D. Ray, K. S. Sharma, A. A. Valverde, G. L. Wilson, X. L. Yan

Faculty Publications

A precision measurement of the β+ decay of B8 was performed using the Beta-decay Paul Trap to determine the β-ν angular correlation coefficient aβν. The experimental results were combined with new ab initio symmetry-adapted no-core shell-model calculations to yield the second-most precise measurement from Gamow-Teller decays, aβν=-0.3345±0.0019stat±0.0021syst. This value agrees with the standard model value of -1/3 and improves uncertainties in B8 by nearly a factor of 2. By combining results from B8 and Li8, a tight limit on tensor current coupling to right-handed neutrinos was obtained. A recent global evaluation of all other precision β decay studies suggested a …

The Effects Of Global Temperature Change On Radon Exposure In Permafrost Areas, Melaan Bender

LSU Master's Theses

Global temperature increase leads to thawing of permafrost that protects local populations from radiation exposure by blocking radon-222 migrating into dwellings. This study aims at assessing the effects of permafrost thawing on the concentrations of radon in indoor air. An approach is developed to predict the evolution of the ²²²Rn concentrations by various processes including radon exhalation from thawed soil. It is found that as frozen soil thaws, more radon can enter dwellings, increasing the concentration of ²²²Rn in indoor air and elevating radiation-induced health risks. This study provides useful insight that will enhance understanding of potential climate …

Phonic Faces As An Intervention To Improve Decoding Skills Of Children With Persistantly Poor Decoding Abilities, Kayla Therese Martin

LSU Master's Theses

Background: Orthographic rules, phonological awareness, and the ability to process morphemes and phonemes from speech and language begins with verbal speech and the child unknowingly recognizes words from his or her environment as early as the senses can process their surroundings. Some children have difficulty integrating these processes to learn how to read. As Ehri (1979) mentions the importance of establishing mental processes, such as amalgamation and phonological recoding, are essential as a basis for establishing reading fundamentals. Decoding occurs through a complex integration of phonological and orthographic knowledge (Ehri 1992). Early readers typically have well-established amalgams for spoken words …

Spatial Mapping Of The Benthic Community And How It Is Used To Research Effects Of Dredging In Louisiana's Lake Borgne., Meghan Johnson

LSU Master's Theses

Benthic communities are vitally important for healthy aquatic ecosystems across Louisiana’s coast. Specifically in Lake Borgne, ecologically important species of fish like the Gulf Sturgeon (Acipenser oxyrinchus desotoi) rely on benthic macrofauna as their main food source. The purpose of this study was to determine the spatial landscape of biodiversity and abundance of the benthic macrofauna community in Lake Borgne. Environmental conditions played a key role in community structure during the study period (fall 2021 through summer 2023) with a major drought occurring in 2023. In 2023, the decline in the abundance of most benthic invertebrates and in …

Examination Of The Effects Of Ultraviolet Radiation On The Toxicity Of An Array Of Pesticides, Polyaromatic Hydrocarbons, And Pharmaceuticals Via In-Vitro Bioassays, Jessica R. Stephens

LSU Master's Theses

Chemicals are often released via anthropogenic means both intentionally and unintentionally into aquatic environments. The chemical fate of these compounds can vary greatly depending on numerous factors that can include but are not limited to salinity, pH, dissolved oxygen, and exposure to ultraviolet radiation. The goal of this study was to investigate the effect of UV radiation on the level of toxicity of different chemicals over time. Chemicals were selected based on previous studies of the toxicity of both parent and metabolites formed as a result of photolysis. Anthracene, phenanthrene, anthraquinone, dicloran, chlorothalonil, hydroxy chlorothalonil, benzobicyclon hydrolysate, and sertraline were …

Enhancement Of Soybean Growth And Disease Resistance Through Seed-Priming Strategy, Francisco Javier Valle

LSU Master's Theses

Disease pressure and other environmental stresses, especially increasing temperature and drought incidence, accompanied with global climatic change have presented hard challenges to Louisiana soybean producers. The objective of this study was to explore the efficacy of seed priming techniques as new alternatives to improve soybean crop protection to reduce the amount of yield losses caused by biotic and abiotic stresses. In this study, five chemicals were used as priming agents at different concentrations (0.1 mM, 1 mM, and 10 mM) to evaluate their effectiveness in enhancing disease tolerance and yield in soybeans. A seed priming procedure was developed by partially …

Reducibility Of Schrödinger Operators On Multilayer Graphs, Jorge Villalobos Alvarado

LSU Doctoral Dissertations

A local defect in an atomic structure can engender embedded eigenvalues when the associated Schrödinger operator is either block reducible or Fermi reducible, and having multilayer structures appears to be typically necessary for obtaining such types of reducibility. Discrete and quantum graph models are commonly used in this context as they often capture the relevant features of the physical system in consideration.

This dissertation lays out the framework for studying different types of multilayer discrete and quantum graphs that enjoy block or Fermi reducibility. Schrödinger operators with both electric and magnetic potentials are considered. We go on to construct a …

Mind The Time: A Synthesis Of Pedagogical Approaches For Improving Rhythm And Meter For Instrumentalists As Applied To Bassoon, Annalea Milligan

LSU Doctoral Dissertations

Rhythm is imperative for the performing musician. This project aims to provide bassoonists with a resource for a rhythmic or metric-focused approach to their applied study. Pedagogical resources for improving rhythm in music through the lens of four categories are identified: experiential, pattern and phrasing, mapping, and repetition. Exercises created from a synthesis of each pedagogical approach demonstrate possible application to bassoon literature by exploring the ways in which an intentional awareness of rhythm can improve technical playing and build practice and performance confidence. By emphasizing the importance of rhythm, its components, and the various approaches to teaching and understanding …

Race And Racism Through The Lens Of Black Men: Exploring The Talk And Lessons Black Fathers Teach Their Children About Race And Racism In America., Conial C. Caldwell Jr

LSU Doctoral Dissertations

The history of racism and racial violence is embedded in the fabric of America and has driven Black people to develop strategies to navigate society that racism has produced. “The Talk” is a racial socialization practice and cultural phenomenon that has existed within Black families for centuries and remains a necessity due to the ongoing acts of racism and violence of Black Americans. Prior research has found that parents rear their children based on their own lived experiences, which many Black Americans have experienced or have been exposed to racism and racial violence. Yet, there are few empirical studies that …

Assessment Of Engineering Performance And Environmental Impacts Of High Reclaimed Asphalt Pavement (Rap) Asphalt Mixtures In Flexible Pavements, Ibrahim A.I.E. Elnaml

LSU Doctoral Dissertations

Due to the critical role of asphalt pavements in national infrastructure development, there is a pressing need to investigate more sustainable materials and approaches. The use of natural aggregates and asphalt binders in asphalt pavement presents sustainability challenges due to the depletion of finite resources. Recycling Asphalt Pavement (RAP) offers a promising sustainable solution by substituting virgin aggregates and asphalt binders with recycled ones. However, increasing RAP contents in asphalt mixtures (>25%) can lead to premature cracking, insufficient durability, and limited longevity due to the presence of aged RAP-asphalt binder. To address these concerns, the application of novel recycling …

Finite Monodromy And Artin Representations, Emma Lien

LSU Doctoral Dissertations

Artin representations, which are complex representations of finite Galois groups, appear in many contexts in number theory. The Langlands program predicts that Galois representations like these should arise from automorphic representations and many examples of this correspondence have been found such as in the proof of Fermat's Last Theorem. This dissertation aims to make an analysis of explicitly computable examples of Artin representations from both sides of this correspondence. On the automorphic side, certain weight 1 modular forms have been shown to be related to Artin representations and an explicit analysis of their Fourier coefficients allows us to identify the …

The Theory Of X-Ray And Neutron Interferometry Using A Modulated Phase Grating, Hunter C. Meyer

LSU Master's Theses

Grating interferometry exploits wave interference to simultaneously image multiple physical properties of an object and can be performed using X-rays or neutrons. The modulated phase grating interferometer (MPGI) is a recently developed interferometry system that allows for the simultaneous acquisition of attenuation, differential-phase contrast, and dark-field images, which highlight X-ray or neutron absorption, refraction, and small angle scatter, respectively. This interferometry system uses a single grating, with a relatively high period envelope function, to produce interference fringes that can be directly resolved by standard high resolution detectors. The grating is sampled at a relatively low pitch, to meet coherence requirements …

Estimating Crustal Thickness In Northwest Louisiana Using The Receiver Function Method, Delton Samuel

LSU Master's Theses

I aim to constrain the crustal thickness of the Sabine Block in the Sabine Uplift region of northwest Louisiana, using the frequency domain receiver function deconvolution technique followed by H-κ stacking. The passive margin on the southern edge of the North American continent experienced an active tectonic history, including the spreading events that led to the formation of the Gulf of Mexico. A previous study proposed the Sabine Block is a residual fragment of Proterozoic orogenic origin; however, its full extent and geometry are up for debate. It is now overlain by thick sedimentary sequences ranging from ~4-6 km deposited …

Investigating The Role Of Fluid Shear Stress During Metastasis On Enhanced Breast Cancer Extravasation, Alejandra M. Ham

LSU Master's Theses

In 2022, ~288,000 American women were diagnosed with metastatic breast cancer which was the leading cause of patient mortality with ~43,000 American women succumbing to the disease. Women can be diagnosed with four different molecular subtypes of breast cancer: luminal A, luminal B, human epithelial growth receptor type 2 enriched (HER2+), and triple-negative breast cancer (TNBC). TNBC accounts for ~12% of all breast cancers, yet it has the worst outcomes. TNBC is highly invasive, with ~46% of TNBC patients developing metastatic disease. A further understanding of metastatic TNBC is needed to provide a greater understanding of how to treat this …

Computational Modeling Of Nanoscale Interaction Of Plasmonic Materials With 2d Materials For Sensing Applications, Maria Iftesum

LSU Master's Theses

Plasmonics is a new and exciting field that has the potential to advance many different types of technology, from information processing and energy harvesting to sensing and imaging. The broad field of plasmonic materials and their potential to improve the functionality of cutting-edge technologies are examined in this thesis.

The thesis explores the synthesis, characterization, and manipulation of plasmonic materials after providing an overview of the basic ideas behind plasmonics. Their distinct plasmonic properties and possible uses are clarified by a thorough investigation of a variety of materials, including noble metals, two-dimensional materials, metal oxides and hybrid structures.

A thorough …

Effects Of Treated Effluent Discharge On Tree Water Use And Growth In A Cypress Swamp., Devin Schexnayder

LSU Master's Theses

Inundated baldcypress (Taxodium distichum) trees generally respond to secondarily-treated and disinfected municipal effluent additions with increased growth rates and reduced mortality. Yet, the effects of effluent additions on the water-use and functional traits of inundated mature baldcypress are poorly understood. Because increased tree growth is associated with increased water use, effluent additions may affect the water budget in coastal swamps by increasing water uptake from the rhizosphere due to increased tree transpiration. I used sap flux density (f_d) measurements to assess water-use traits and tree-level daily transpiration (E) in seven mature inundated baldcypress trees that had …

Subgroups Of Coxeter Groups And Stallings Foldings, Jake A. Murphy

LSU Doctoral Dissertations

For each finitely generated subgroup of a Coxeter group, we define a cell complex called a completion. We show that these completions characterizes the index and normality of the subgroup. We construct a completion corresponding to the intersection of two subgroups and use this construction to characterize malnormality of subgroups of right-angled Coxeter groups. Finally, we show that if a completion of a subgroup is finite, then the subgroup is quasiconvex. Using this, we show that certain reflection subgroups of a Coxeter are quasiconvex.

Analytic Wavefront Sets Of Spherical Distributions On The De Sitter Space, Iswarya Sitiraju

LSU Doctoral Dissertations

In this work, we determine the wavefront set of certain eigendistributions of the Laplace-Beltrami operator on the de Sitter space. Let G′ = O_1,n(R) be the Lorentz group, and let H′ = O_1,n−1(R) ⊂ G′ be its subset. The de Sitter space dSⁿ is a one-sheeted hyperboloid in R^1,n isomorphic to G′/H′. A spherical distribution is an H′-invariant eigendistribution of the Laplace-Beltrami operator on dSⁿ. The space of spherical distributions with eigenvalue λ, denoted by D_λ^H'(dSⁿ), has dimension 2. We construct a basis for the space of …

Thermal Frontal Polymerization – Applications In Coatings And Composites, Maria Martinez

LSU Doctoral Dissertations

Thermal frontal polymerization has long been used as a method to cure composites and coatings. However, this is the first time these applications have been used without the use of a catalyst, for the case of composites and coatings.

Chapter 2 discusses how to optimize cure-on-demand, thin layer coatings, using frontal polymerization. Previously, for the use of curing thin layer coating using thermal FP, it was known to just make the formulation viscous enough, as this would prevent premature quenching caused by heat loss. It was discovered that for a given layer thickness, a minimum viscosity and initiator concentration were …

The Modular Generalized Springer Correspondence For The Symplectic Group, Joseph Dorta

LSU Doctoral Dissertations

The Modular Generalized Springer Correspondence (MGSC), as developed by Achar, Juteau, Henderson, and Riche, stands as a significant extension of the early groundwork laid by Lusztig's Springer Correspondence in characteristic zero which provided crucial insights into the representation theory of finite groups of Lie type. Building upon Lusztig's work, a generalized version of the Springer Correspondence was later formulated to encompass broader contexts.

In the realm of modular representation theory, Juteau's efforts gave rise to the Modular Springer Correspondence, offering a framework to explore the interplay between algebraic geometry and representation theory in positive characteristic. Achar, Juteau, Henderson, and Riche …

Profiling Of Voltage-Gated Sodium Channel Subtype Expression And Resulting Susceptibility To Targeted Osmotic Lysis In Cancer, Spencer Gerard Lemoine

LSU Doctoral Dissertations

Cancer is a disease characterized by a wide array of dysregulated cellular function, activity, and growth. At times, specific dysregulations associated with cancer can be exploited as avenues of potential treatment. The sodium handling mechanisms and their associated proteins in cancer have received closer attention recently closely as such a potential mechanism to exploit for treating advanced cancer. Some novel treatments aim to inhibit the expression or activity of these sodium handling proteins in an attempt to prevent the cancer from advancing or becoming more aggressive; however, such approaches have had limited success. Targeted osmotic lysis (TOL) is a new …

Round Ii: Exploring The Experiences Of Black, First-Generation Graduate And Professional Students At Historically Black Colleges And Universities (Hbcus), Derrick D. Lathan

LSU Doctoral Dissertations

This phenomenological study explores the experiences of Black, first-generation (first-gen) students pursuing advanced degrees at historically Black colleges and universities (HBCUs), following the COVID-19 pandemic and racial justice movements like Black Lives Matter. Additionally, this study examines the present-day motivations to pursue advanced degrees, particularly the benefits of doing so at an HBCU. The main research question guiding this study is: What are the experiences of Black, first-gen graduate and professional students at historically Black colleges and universities (HBCUs)? The sub-questions are:

1. How do Black, first-gen graduate and professional students describe being a first-gen student?
2. What barriers and supports impact …

“Redención”: Testimonios Of Latinas Who Chose To Leave The Higher Education Industry, Delia P. Madrid-Nothdurft

LSU Doctoral Dissertations

Using the methodological framework of testimonio, this study was an exploration of the experiences of former higher education professionals who identify as women in the Latinx community. Grounded in Latino Critical Theory (LatCrit) and Critical Race Feminism (CRF), this research aims to highlight the narratives of Latina professionals who have separated from the higher education sector. The study is informed by the conceptual framework of Chicana feminist perspective, which contextualizes the analysis of these experiences within a socio-cultural context. Using semi-structured interviews, participants shared their testimonios, providing rich accounts of their journeys and challenges within higher education. Through thematic …

Applied Depositional Geosystems Of The Coos Bay Basin, Oregon: Organic Geochemistry, Maturation, Paleoenvironmental Reconstruction And Biostratigraphy Of The Coaledo Delta During The Middle Eocene Climatic Optimum (Meco), Allison K. Barbato

LSU Doctoral Dissertations

The Coos Bay Basin on the southwestern coast of Oregon is a forearc basin that contains exceptionally preserved Eocene to Miocene, tidal to wave-dominated, shallow deltaic to deep marine sediments of the Coaledo Delta. Coastal depositional environments are known to host source, reservoir, and seal rocks. Climate, topographic relief, and geographical position all play an important role in regional vegetation development and oceanic setting. This study assesses 84 outcrop and 12 core samples from Coos Bay for their organic geochemical characteristics and microfossil assemblage to provide source rock characterization information, organofacies descriptions, environmental reconstructions, and age control.

Results indicate the …

Starting Small Or Big: An Artificial Language Paradigm, Rachel Evans

LSU Master's Theses

Previous research on language acquisition has raised two competing hypotheses: Starting Small and Starting Big. Starting Small states that limitations (small working memory capacity, simple structure, short string length, etc.) are beneficial for language learning, which explains why children are able to acquire language more easily than adults. Starting Big proposes the opposite, that input of chunks of language rather than individual units creates a stronger and more fluid understanding of grammatical relations between words. The current study aimed to investigate these theories in the context of an artificial language paradigm using a forced-choice task, a production task, a working …

Two New Catalysts For Oxidation Of Water To Oxygen, Takia Sultana

LSU Master's Theses

If fuels, such as hydrogen or methanol, are to be produced from renewable energy (solar or wind) in the future, efficient catalysts will be needed, not only for fuel production reactions but for the essential simultaneous oxidation of water to O₂. Ruthenium complexes are among the more promising water oxidation catalysts (WOCs). Two new isomeric ruthenium WOCs have been prepared based on the benzylpyridyltriazole ligand (Figure 3); trans-py-[Ru(tpy)(bpt)(H₂O)]²⁺ (trans-py-1) and trans-trz-[Ru(tpy)(bpt)(H₂O)]²⁺ (trans-trz-1) (tpy = 2,2’:6’,2’’-terpyridine, bpt = benzylpyridyltriazole). Ceric ammonium nitrate [(CAN)/Ce(IV)] oxidants were …

Settling Preference Of Nipponaclerda Biwakoensis (Hemiptera: Aclerdidae) On Phragmites Australis Stems, Alexia Catherine Desoto

LSU Master's Theses

Phragmites australis, a wetland grass that stabilizes the Louisiana coastline, has been undergoing a major die-off near the Mississippi River Delta (MRD) since the autumn of 2016. One suspected cause for this plant decline is the attack of an invasive scale insect, Nipponaclerda biwakoensis. We lack information on the host preference of the crawlers, the life stage that decides where to settle and when to start feeding on the plant. The objectives of this study were to identify what positions along the vertical stem N. biwakoensis prefers to settle and what host-plant traits may be influencing this choice. We recorded …