Correlative In Situ Nonlinear Optical Characteriztion Of Plasmonic Colloidal Nanoparticle Growth Dynamics, Stena C. Peterson

LSU Doctoral Dissertations

Colloidal noble metal nanoparticles are of extreme interest as nanomaterials and for the wide variety of their possible applications in nanomedicine. The unique linear and nonlinear optical processes associated with these nanomaterials can be studied using a variety of spectroscopic techniques including extinction, second harmonic generation (SHG), and two-photon fluorescence (TPF) spectroscopy. In order to better understand and optimize these nanomaterials for their desired applications, it is important to investigate the growth and photophysical dynamics associated with gold nanoparticles, silver-gold core-shell (Ag-Au CS) nanoparticles, and gold-silver-gold core-shell-shell (Au-Ag-Au CSS) nanoparticles in addition to how their size, surface morphology, composition. and …

Extreme Geomagnetic Storm Effects On Earth's Radiation Belts Observed By Calet On The International Space Station, Anthony W. Ficklin

LSU Doctoral Dissertations

This dissertation examines changes in Earth's energetic-particle environment using measurements from the Calorimetric Electron Telescope (CALET) on the International Space Station. Although CALET was designed primarily for high-energy cosmic-ray and gamma-ray observations, its count rates provide nearly continuous measurements of particles of ~1 MeV and above. The analysis uses the CHDX, CHDY, and IMC4X channels, which have approximate electron thresholds of $>\!1.5$, $\!>3.4$, and $\!>8.2$~MeV and proton thresholds of $>\!17$, $\!>37$, and $\!>52$~MeV, respectively. Because these measurements do not identify particle species, the observations are interpreted using their geographic and geomagnetic distributions, the relative …

The Study Of Hydrophobic Biomolecules With Matrix Assisted Laser Desorption Ionization Mass Spectrometry And Atomic Force Microscopy, Brandy L. Perkins

LSU Doctoral Dissertations

Abstract

Matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS) can be used to obtain localization and chemical information of hydrophobic biomolecules on tissue samples.  A technique has been developed to modify a standard MALDI matrix that improves the selectivity for hydrophobic biomolecules on the tissue sample. The modification involves the use of a Group of Uniform Materials Based on Organic Salts (GUMBOS). GUMBOS are ionic liquids (IL) that are bulky organic ions with a counter ion that can be changed for tuning.  They are more stable than traditional matrices under vacuum.  Unlike traditional IL’s, the GUMBOS melting point ranges …

A Data-Driven Framework For Mitigating Breast Cancer Overdiagnosis: From Estimation To Risk-Adjusted Computer-Aided Diagnosis, William M. Brown Jr.

LSU Doctoral Dissertations

In Computer-Aided Diagnosis (CAD) of cancer, standard cost metrics (false-positives and false-negatives) fundamentally fail to account for overdiagnosis. Overdiagnosis is a critical scenario where a disease is correctly detected (true-positive) but is biologically indolent and would never have caused the patient harm or symptoms. While widely recognized in the medical community as a major healthcare crisis driving stressful and invasive overtreatment, overdiagnosis remains severely under-researched within computer science and engineering. This dissertation addresses this interdisciplinary gap by defining the three key computational challenges of overdiagnosis: (i) accurate estimation, (ii) harm quantification, and (iii) algorithmic mitigation. To overcome the estimation challenge, …

Scattered Light Noise At Ligo Livingston Observatory Induced By Microseismic Ground Motion, Debasmita Nandi

LSU Doctoral Dissertations

Gravitational waves are “ripples” in the fabric of spacetime and create a minuscule change in the distance between two points. After publishing his theory of general relativity in 1915, Albert Einstein predicted the existence of gravitational waves as a consequence of the theory. Almost 100 years after the theoretical prediction, gravitational waves were detected for the first time in 2015 by the Advanced LIGO detectors in Livingston, Louisiana, and Hanford, Washington. Gravitational waves have a very small amplitude, making it very challenging to detect them. Different types of noise sources either of instrumental or environmental origin can reduce the astrophysical …

Teaching Through Sound: Approaches To The Use Of Fixed Media In Pedagogical Viola Etudes, Roberto C. Mochetti Jr.

LSU Doctoral Dissertations

This dissertation examines the pedagogical possibilities of fixed media in newly composed viola etudes. While fixed media is commonly treated as accompaniment or as a performance medium, this project argues that it can also serve as an active component of technical and musical training. By providing stable and repeatable sonic environments, fixed media can support forms of listening, intonation, sound production, and performer awareness that are difficult to cultivate through traditional etudes alone. This argument responds to a broader pedagogical gap in string training, where long-established etudes and models of technical development remain central even as contemporary viola performance increasingly …

Effects Of Peer Tutoring Training Duration And Group Piano Level On Harmonization And Transposition Achievement And Learning Attitudes Of Undergraduate Non-Keyboard Music Students, Jinnan Liu

LSU Doctoral Dissertations

The purpose of this study was to examine the relationships among peer tutoring training duration, group piano level, and undergraduate non-keyboard music students’ achievement in harmonization and transposition, as well as their learning attitude following peer tutoring. Based on the literature on cooperative learning, peer-assisted learning, and reciprocal peer tutoring, this study examined whether differences in training duration and group piano level were related to student performance and learning experiences in university group piano.

A quasi-experimental 2  2 design was used. The independent variables were peer tutoring training duration (2-day vs. 4-day) and group piano level (Group Piano II vs. …

Unraveling The Nanoscopic Characteristics Of The Heterogeneous Deep Eutectic Solvent Formed By Lauric Acid And N-Methylacetamide: An Experimental And Computational Approach, Laura X. Sepulveda

LSU Doctoral Dissertations

Deep eutectic solvents (DESs) are attractive systems for extraction and separation of compounds. One example of this is the DES formed by the combination of lauric acid (LA) and N-methylacetamide (NMA), system that has been shown to efficiently separate oil/water mixtures through gel formation between LA and oil molecules. Structural characterization of this system using small-angle X-ray scattering (SAXS) and vibrational spectroscopy revealed the existence of nanometer-scale LA domains embedded in a continuous polar NMA phase, where LA and NMA interact through hydrogen bonding. These LA domains are responsible for the separation efficiency of linear organic molecules. However, this DES …

Evaluating Soil Health And Crop Yield In Louisiana Agricultural Systems: Impacts Of Best Management Practices And Prediction Models, Hector J. Mendoza Lagos

LSU Doctoral Dissertations

The adoption of conservation management practices is critical for improving soil health, enhancing nutrient use efficiency, and sustaining crop productivity in row crop systems in Louisiana. This study evaluated the role of conservation agronomic practices, soil biochemical indicators, and machine learning predictive models to improve soil nutrient dynamics, soil health indicators, microbial communities (MC), and crop productivity on a corn (Zea mays L.) research plot scale and in a commercial forty-hectare cotton (Gassypium hirsutum L.)-corn-soybean (Glycine max L.) rotation system in northeast Louisiana. The objectives of the study were to evaluate soil nutrient dynamics and MCs under …

Momentum Space Algorithm For Electronic Structure Of Double-Incommensurate Trilayer Graphene, Kenneth Silver Beard

LSU Doctoral Dissertations

Numerical algorithms for computing the electronic structure of incommensurate 2D-materials using ab initio models are critical for predicting material properties and guiding experiments. For bilayers, momentum space and continuum models have been introduced to approximate observables of ab initio tight-binding models using a momentum description, despite the lack of periodicity in the tight-binding model required for Bloch theory. A similar structure has been introduced for double-incommensurate trilayers using a continuum model, where the three lattices are mutually incommensurate. However, this description leads to a four-dimensional lattice space, and numerical convergence of the density of states has been observed to be …

Machine Learning Based Models For Simulation And Analysis Of Bulk Earth Melt System, Abin Shakya

LSU Doctoral Dissertations

Understanding the segregation of bulk Earth melt systems into metallic (core) and silicate (mantle) phases under high-pressure and high-temperature conditions is central to modeling Earth’s interior, yet relevant experimental and computational studies remain limited. This work develops a machine learning–based simulation pipeline that iteratively couples first-principles (quantum mechanical) calculations with neural network training to generate high-fidelity force fields. Using major-element Fe–Mg–Si–O melt systems, with and without H and N, as testbeds, we demonstrate that this framework enables large-scale molecular dynamics simulations at near first-principles accuracy. We further introduce a sequence of phase identification methods, progressing from statistical binning of elemental …

Extremal Connectivity In Graphs And Matroids, Yiwei Ge

LSU Doctoral Dissertations

Connectivity is a central theme in both graph theory and matroid theory. This dissertation investigates extremal connectivity in graphs and matroids, with emphasis on unavoidable structures and minimal connectivity phenomena.

Chapter 2 introduces cycle-contraction minors of graphs and investigates their structural properties. We establish a connection between cc-minors and induced subgraphs via graph duality. The main result gives an unavoidable-families characterization for cc-minors of sufficiently large loopless $2$-connected graphs.

Chapter 3 studies super-minimally $3$-connected graphs, namely $3$-connected graphs that have no proper $3$-connected subgraphs. We establish extremal bounds on structural parameters of these graphs, including the minimum number of degree-$3$ …

Circuits And Enumeration Problems For Matroids, Christine H. Cho

LSU Doctoral Dissertations

This dissertation is a collection of work concerning the structure and enumeration of circuits and other distinguished sets in a matroid. The Tutte polynomial, recognized as the universal deletion-contraction invariant in matroid and graph theory, is a natural starting point when considering enumeration problems for matroids. The main result in Chapter 2 generalizes a theorem of Dean Lucas concerning the Tutte polynomial and its behavior under rank-preserving weak maps. This generalization provides an avenue for comparing the numbers of circuits, bases, rank-k flats, and hyperplanes of a matroid containing an element given two distinct, yet related, elements.

Chapter 3 addresses …

Theory, Experiments, And Image Recovery Algorithms For X-Ray Interferometry, Hunter C. Meyer

LSU Doctoral Dissertations

Purpose: X-ray grating interferometry is a form of X-ray phase contrast imaging capable of simultaneously measuring attenuation, differential-phase, and dark-field images arising from X-ray absorption, refraction, and small-angle scattering, respectively. These additional contrast mechanisms have potential clinical and industrial applications, particularly for lung tissue characterization and disease identification. As grating interferometers approach clinical viability, key challenges include reducing X-ray dose, mitigating mechanical instability, and correcting spectral artifacts resulting from beam hardening.

Methods: The modulated phase grating interferometer (MPGI) is a potential solution for reducing X-ray dose by eliminating the analyzer grating used in alternative interferometer designs, including the Talbot-Lau interferometer …

Theta Series And Their Applications, Koustav Mondal

LSU Doctoral Dissertations

Theta series encode the number of representations of integers by quadratic forms in their Fourier coefficients and connect classical counting problems to the theory of modular forms and elliptic curves. On the other hand, theta series connect with hypergeometric series via Ramanujan’s theory of elliptic functions to alternative bases. This dissertation explores these connections and applies theta series to solve problems involving representations of integers  and  special values of $L$-functions. We analyze the theta series associated to the quadratic form $Q(\Vec{x})=x_1^2+x_2^2+x_3^2+x_4^2$ with congruence conditions on $x_i$ modulo $2,3,4$ and $6$. By interpreting theta series as modular forms, we can express …

Making The Right Decisions For Adaptive Radiotherapy, Chloe C.F. Ditusa

LSU Doctoral Dissertations

Purpose: Daily anatomical changes can invalidate the geometric, dosimetric, and biological assumptions of reference radiotherapy plans, yet quantitative evidence describing fraction-level deviations across disease sites remains limited. This work developed and evaluated a metric-based framework for daily dose assessment to characterize temporal treatment behavior and inform adaptive decision-making in Head and Neck (H&N) radiotherapy and Prostate stereotactic body radiotherapy (SBRT). Methods: A web-based Dashboard was created to compute geometric, dosimetric, and radiobiological metrics from daily dose recalculations. Calculations were first verified against a commercial treatment-planning analysis platform. Daily dose on anatomy-of-the-day was reconstructed using CBCT-based pseudo-CTs for H&N and daily …

Secondary English Teachers’ Perceptions And Experiences With The Ela Guidebooks Curriculum: A Phenomenological Study, Bodie Dufrene

LSU Doctoral Dissertations

As standards-based curriculum reforms expand across the United States, school districts have increasingly adopted scripted curricular materials to promote coherence across classroom practice and strengthen alignment to standardized assessments. Within Louisiana, efforts to align English instruction to the Common Core State Standards manifested in the creation of the ELA Guidebooks curriculum by the Louisiana Department of Education. Guidebooks provides teachers with sequenced units of instruction organized around a central novel, explicit directions, pacing guidance, and cumulative writing tasks aligned to central unit questions. This qualitative study explored how secondary (i.e., grades 6-12) English teachers perceived and described their experiences implementing …

An Analysis And Performer's Guide Of Boulder Canyon, Hoover Dam By Clark Hubbard, Tyler Hawk

LSU Doctoral Dissertations

Clark Hubbard is currently the Assistant Director of the Vanderbilt Marching and Athletic Bands. He is active as an American percussionist, composer, artist, and educator. His compositions have been performed throughout the United States and overseas, including solo, chamber, percussion, and electronic compositions. This document aims to analyze Boulder Canyon, Hoover Dam, discussing how the fixed media influences musical decisions. This document is also a performer’s guide for the piece.

Percussion with fixed media has been composed for since the early to middle 1900s. Inspiration from the techniques and early pieces of fixed media composition can be found in …

Forbidden Induced Restrictions And Unavoidable Minors In Matroids, Matthew P. Mizell

LSU Doctoral Dissertations

Targets are matroids that arise from a nested sequence of flats in a projective geometry. This class of matroids was introduced by Nelson and Nomoto, who found the forbidden induced restrictions for binary targets. In this dissertation, their result is generalized to targets arising from projective geometries over $GF(q)$. In addition, targets arising from nested sequences of affine flats are introduced and the forbidden induced restrictions for these affine targets are determined.

In 1963, Halin and Jung proved that every simple graph with minimum degree at least four has $K_5$ or $K_{2,2,2}$ as a minor. Mills and Turner proved an …

Biogeochemical Controls On Phosphorus Transport And Legacy Storage Across A Coastal Watershed, Lee Potter

LSU Doctoral Dissertations

Excess phosphorus (P) loading is a key driver of eutrophication and harmful algal blooms (HABs) in aquatic systems worldwide. This relationship is of increasing concern in coastal Louisiana, where climate variability, altered hydrology, and land-use change converge, resulting in increased hydrologic and nutrient loading into coastal systems. This dissertation examines controls on P cycling in the Lake Pontchartrain Basin through a multi-scale framework linking estuarine processes, watershed loading, climate and weather patterns, and sediment dynamics. The dissertation begins with an overview of the study region, P dynamics, and changes in hydrology and nutrient loading patterns. Chapter 2 presents a spatial …

Improving Stem Assessments: Strategies For Increasing The Accessibility And Adoption Of Two-Stage Exams, Kristina Callaghan

LSU Doctoral Dissertations

Over three decades of research have shown that students taught using active learning strategies achieve better learning outcomes compared to those taught using traditional methods. Two-stage exams, which pair a traditional exam with a group component, are an increasingly popular method for incorporating active learning within the assessment component of a course. Previous studies have shown this assessment strategy provides a variety of benefits for students, including increased engagement and collaboration, immediate feedback, and potentially increased content retention. However, the unique circumstances of each instructor can pose a non-trivial barrier to the implementation of two-stage exams. In this thesis, we …

Applications For The Quasi-Atomic Orbital And Constrained Density Functional Theory Methods On Catalytic Reactions, Alvaro David Loaiza Orduz

LSU Doctoral Dissertations

Selective activation of C–O, C–H, and C–C bonds underpins biomass upgrading, alkane functionalization, and CO₂ conversion. Despite their importance, the electronic factors governing catalytic performance remain incompletely understood, and many industrial processes still rely on empirical trends or material-specific observations. This dissertation addresses this gap by applying density functional theory (DFT), thermodynamic decomposition, and electronic-structure analysis to identify unifying principles of reactivity across transition-metal phosphides, vanadate oxides, copper-based electrocatalysts, and mixed IrO₂–RuO₂ layers. This work examines how charge transfer, orbital localization, and ligand-induced perturbations control reaction pathways in diverse catalytic systems. C–O bond scission in 2-methyltetrahydrofuran (MTHF) and methanol was …

Measurement Of 18f(Alpha,P)21ne With The Array For Nuclear Astrophysics And Structure With Exotic Nuclei (Anasen), Keilah S. Davis

LSU Doctoral Dissertations

Certain (α,p) reactions on proton-rich nuclei are among the most important nuclear reactions occurring during Type I X-ray bursts, as well as being impactful in stellar explosions during the Asymptotic Giant Branch (AGB) phase and on accreting white dwarfs (WD). However, large uncertainties remain for reaction rates on some radioactive nuclei due to the lack of direct measurements. The Array for Nuclear Astrophysics and Structure with Exotic Nuclei (ANASEN) is a gas target and charged-particle detector designed for direct measurements of (α,p) reactions. ANASEN was redesigned with two hexagonal barrels of 100-µm-thick silicon strip surrounding the beam axis over a …

Metacommunity Coupled Epidemiological And Biophysical Modeling Of An Emergent Coral Disease, Benjamin Holmes Farmer

LSU Doctoral Dissertations

Emerging infectious diseases pose imminent risk to the marine realm and coral reefs in particular. Since its emergence in 2014, stony coral tissue loss disease (SCTLD) has dramatically reduced living coral cover in Florida and charted a similar course in the Caribbean. SCTLD is by far the most severe coral disease in history and has driven highly susceptible species to local extinction, yet the mechanisms driving the regional epizootic are not well understood. Here, we developed reef-scale parameterizations of disease spread using model sites in the lower Florida Keys, developed extensive metacommunity habitat maps for the US Caribbean, and then …

Quantifying Uncertainty In Landscape Evolution And Provenance Analysis: Insights From Statistical And Numerical Modelling, Vivian Carmello Grom

LSU Doctoral Dissertations

Landscape evolution models (LEMs) and detrital zircon provenance are widely used to investigate Earth surface processes, yet both face challenges related to quantifying model behavior and interpreting sedimentary signals under realistic, heterogeneous conditions. This thesis addresses these challenges through analysis and case studies that develop and apply new approaches for analyzing landscape dynamics and assessing uncertainties in sediment provenance.

Chapter 1 introduces a quantitative framework for evaluating LEM outputs using Shannon Entropy, Moran’s I, and Geary’s C. Applied to simulations with steady uplift, periodic uplift, spatially variable uplift, and a timeseries of DEMs, these metrics capture spatial organization and information …

Satellite-Mediated Quantum Clock Synchronization: Towards Precise Timing At A Global Scale, Sage B. Ducoing

LSU Doctoral Dissertations

Accurate timekeeping is essential for scientific and technological advancements, particularly in areas of communication, networking, navigation, and high precision measurements. While many methods of time resolution are already established using classical resources, they fail to combine high precision outcomes with large-scale implementations. Additionally, numerous quantum networking architectures using satellite-assisted methods have demonstrated quantum communication on scales exceeding ground-based methods. For these reasons, we propose the use of a time synchronization method by which pairs of highly time-correlated photons are exchanged between clocks on satellites and clocks on Earth, al- lowing users to reconstruct the time offsets between their clocks. This …

Cache-Conscious Sparse Matrix Dense Matrix Multiplication On Gpus, Haoqiang Guo

LSU Doctoral Dissertations

Over the past decade, high-performance deep learning has evolved into a critical research domain, driven by the demand for efficient models and high inference throughput. Deep learning architectures have shifted from stacked convolutional layers to transformer-based models, while pruning techniques and graph-structured data have established sparse matrix–dense matrix multiplication (SpMM) as a fundamental kernel—particularly in graph neural networks (GNNs). Modern GPUs, with their massive parallelism and high-bandwidth memory, offer immense potential for accelerating these workloads. While SpMM implementations using the compressed sparse row (CSR) format remain common to avoid conversion overhead, preprocessing-based methods have recently demonstrated superior potential. In GNN …

Equity-Aware Natural Hazards Resilience Assessment And Improvement Of Road Networks, Naqib Mashrur

LSU Doctoral Dissertations

As climate change intensifies the frequency and severity of hurricanes, the resulting flood events pose escalating threats to transportation infrastructure and community well-being. This dissertation addresses the intersection of flood resilience, network connectivity, and social equity by integrating principles from network analysis, equity planning, and disaster resilience. The research begins by examining the social dimensions of accessibility loss during hurricane-induced flooding. Spatial and demographic analysis reveals that Native American and Hispanic populations in the case study region experience the most significant reductions in access to essential service facilities, highlighting inequities in systems.

Investigating a region southern Louisiana road network demonstrates …

Determining The 17f(Α,P)20ne Reaction Rate For Application In Type I X-Ray Bursts, William Braverman

LSU Doctoral Dissertations

The ¹⁷F(α, p)²⁰Ne reaction has been identified as an alternate pathway for breakout from the hot-CNO cycle that can be important in some X-ray burst scenarios. The ¹⁷F(α, p)²⁰Ne reaction rate was previously determined through a parameterized exponential S-factor with a large enhancement from thermally-excited states based on statistical models with large uncertainties. We have measured the time-inverse ²⁰Ne(p,α)¹⁷F cross section at center-of-mass energies ranging from 5.50 to 7.10 MeV using an activation method with a proton beam on a neon gas cell. Coincident detections of 511-keV γ-rays, resulting from electron-positron …

Practical Real-Time Permanent Magnet Energy Spectrometer Using A Diode Array For Therapeutic Electron Beam Tuning And Quality Assurance, Mason W. Heath

LSU Doctoral Dissertations

Purpose: Develop a practical, real-time permanent magnet electron energy spectrometer and evaluate it for beam tuning and quality assurance (QA) of therapeutic electron beams.

Methods: Aim 1: A 0.55 T permanent magnet was coupled to Sun Nuclear SRS MapCHECK® PC boards, providing two interlaced diode arrays. Detector response, R_meas(z_diode) versus diode position z_diode, was extracted from raw diode array readings, correcting for diode sensitivity and other factors. Using Monte Carlo (MC) computed, monoenergetic detector response functions, a curve-fitting algorithm extracted the energy spectrum, from R_meas(z_diode). The energy spectra for 7-20 …