Intraspecific Variation In Morphological And Biochemical Responses To Salinity And Flooding In Phragmites Australis, Olivia Hurley

LSU Master's Theses

Phragmites australis is a widespread wetland plant species with numerous haplotypes, several of which are highly invasive. In low-lying coastal marshes of Louisiana, the Delta-type (haplotype M1) dominates across a wide range of salinity and flooding environments. This suggests that Phragmites may be highly adaptable to diverse environmental conditions and that there may be a genetic component, as seen in other coastal wetland plant species. While non-native Phragmites haplotypes are targeted for control and removal in many areas, they are considered beneficial for marsh stabilization and contributing to elevation gain in coastal Louisiana, where several areas experience rapid land loss. …

Optimizing Llm X86 Assembly Code Comprehension Through Fine-Tuning, Darrin Michael Lea

LSU Master's Theses

Reverse engineering is a cybersecurity process that focuses on understanding the underlying functionality of software or malware. This is an arduous process that demands large amounts of time and effort from cybersecurity practitioners. Large Language Models (LLMs) offer a potential solution to this problem. LLMs have worked their way into various fields of cybersecurity in recent years, including incident response and malware classification. However, LLMs have historically struggled with low-level code comprehension: a necessary part of reverse engineering. While LLMs can generate code and explain its function on the surface level, they struggle to grasp the wider context. In this …

Innovative Design Methodology For Durable Open-Graded Friction Course Asphalt Mixtures, Anas Abualia

LSU Doctoral Dissertations

Open-graded friction course (OGFC) is a thin asphalt mixture surface layer with a high percentage of coarse aggregates and high interconnected air voids, which provides improved skid resistance, visibility, and decreased pavement-tire noise. However, construction personnel at DOTD reported that conventional OGFC mixtures have short service life (raveling distress). Further, their structural contribution to the pavement structure is commonly neglected and designed only for functionality purposes.

The objective of this study was to develop a rational mix design methodology to improve the durability of OGFC asphalt mixtures. Specific objectives are to: (1) conduct a rheological and chemical characterization of polymer-, …

Modeling And Simulation Of Methane And Co2 Hydrates In Porous Media, Chico Sambo

LSU Doctoral Dissertations

This dissertation presents a comprehensive study on modeling and simulation for
methane hydrate production and CO2 sequestration. The research focuses on pore-
scale and reservoir-scale modeling techniques to understand the dynamics of gas
hydrate dissociation, the associated risks of subsidence, and the potential for CO2
storage in deep-sea environments.
This dissertation begins with an investigation into pore-scale modeling. Specif-
ically, a detailed pore network model was developed to simulate the processes of
methane hydrate dissociation and formation. However, the numerical simulations
revealed that assuming an isothermal process for hydrate formation and dissociation
is not physically realistic. Consequently, the results obtained …

Privacy At Scale: A Study Of Mobile App Privacy Practices, Katherine Perez

LSU Master's Theses

What is privacy in a world where people are more connected than ever? Due to the Internet and its rapid advancement, the way information is shared and accessed has fundamentally changed. Millions of people interact with social networks, websites, and applications daily—and with each interaction, some data is collected from the user. In many cases, users cannot access a website or application without first accepting the service’s Privacy Policy. However, these policies often obscure the details of how a consumer’s data is handled, burying important information under dense legal language. In response to growing concerns about transparency, some platforms have …

Unfitted Finite Element Methods For Shape Optimization And Liquid Crystals, Jeremy T. Shahan

LSU Doctoral Dissertations

We present an approach to shape optimization problems that uses an unfitted finite element method (FEM). The domain geometry is represented, and optimized, using a (dis- crete) level set function and we consider objective functionals that are defined over bulk domains. For a discrete objective functional, defined in the unfitted FEM framework, we show that the exact discrete shape derivative essentially matches the shape derivative at the continuous level. In other words, our approach has the benefits of both optimize-then- discretize and discretize-then-optimize approaches.

Specifically, we establish the shape Fréchet differentiability of discrete (unfitted) bulk shape functionals using both the …

“When Black Women Whisper”: An Exploration Of Why Black Women Stay In K-12 Education, Chelsea Lynne Murry

LSU Doctoral Dissertations

Abstract

From low retention rates to race and gender biases to being overworked and undervalued in the classroom, Black women leave education at higher rates than any other demographic. This study highlighted the experiences of Black women in K-12 education settings, the role of support systems in their retention and advancement, and why they stay in K-12 education. The study used Counter-storytelling in Critical Race Theory, Black Feminist Thought, and Womanism to examine the race and gender inequities that Black women face and to highlight their lived experiences. Through the use of Sista Circles/focus groups and one-on-one interviews, the research …

Optimizing Fisher Information In Quantum Technology, Bran Purvis

LSU Doctoral Dissertations

Fisher information is a statistical metric whose inverse represents a lower bound on the variance of an unbiased estimator. Naturally, in order to make the best estimates of a given unknown parameter, one would desire to find ways to minimize the value of this lower bound. Thus, the Fisher information can also be used to compare the quality of different estimators for a given parameter: whichever estimator has a lower value for its Fisher information must also provide better estimates. The same holds true in the framework of quantum information theory, where an analog to the Fisher information, dubbed quantum …

Identifying Saharan Air Layer Events And Their Relationship To Instability And Rainfall Patterns In The Tropical North Atlantic Ocean, Charles H. Dolce

LSU Master's Theses

Every year, strong North African winds across the Sahara loft dust particles and advect them westward within the Saharan Air Layer (SAL). These plumes of dust often reach the Caribbean Sea and can heavily affect regional weather patterns by suppressing convection. When concentrations are high, decreased rainfall can yield negative societal and ecological impacts, potentially leading to drought. The Puerto Rican early rainfall season (ERS), spanning from 1 April through 31 July, overlaps with Saharan dust migration periods, and systematically detecting instances of SAL activity near the island is important for understanding longer-term drought-forcing trends in the region.

Corridors of …

Chain Theorems For Different Classes Of 3-Connected Graphs, Avin Sunuwar

LSU Doctoral Dissertations

This dissertation explores the structural properties of graphs by extending the classical result of Tutte's Wheel Theorem. In particular, we develop an improved version of Tutte's Wheel Theorem along with new chain theorems for subclasses of 3-connected graphs. These chain theorems provide a systematic approach to characterizing graphs that exclude certain minors, leading to significantly shorter proofs of established results.

In Chapter 5, we present a generalization of the block-tree theorem for connected graphs, which removes the restriction on cut vertices and allows greater flexibility in separator sizes. By integrating the results from Chapters 3, 4, and 5, we …

Gaussian Quantum Markov Semigroups In The Fock-Anti-Fock Representation Of Weyl Algebra, A Dhahri, Franco Fagnola, D Poletti, Hyun Jae Yoo

Journal of Stochastic Analysis

No abstract provided.

A Skill Assessment Framework For The Fisheries And Marine Ecosystem Model Intercomparison Project, Nina Rynne, Camilla Novaglio, Julia Blanchard, Daniele Bianchi, Villy Christensen, Marta Coll, Jerome Guiet, Jeroen Steenbeek, Andrea Bryndum-Buchholz, Tyler D. Eddy, Cheryl Harrison, Olivier Maury, Kelly Ortega-Cisneros, Colleen M. Petrik, Derek P. Tittensor, Ryan F. Heneghan

Faculty Publications

Understanding climate change impacts on global marine ecosystems and fisheries requires complex marine ecosystem models, forced by global climate projections, that can robustly detect and project changes. The Fisheries and Marine Ecosystems Model Intercomparison Project (FishMIP) uses an ensemble modeling approach to fill this crucial gap. Yet FishMIP does not have a standardised skill assessment framework to quantify the ability of member models to reproduce past observations and to guide model improvement. In this study, we apply a comprehensive model skill assessment framework to a subset of global FishMIP models that produce historical fisheries catches. We consider a suite of …

Exact Inference For Transformed Large-Scale Varying Coefficient Models With Applications, Tianyu Chen, Robert Habans, Thomas Douthat, Jenna Losh, Lida Chalangar Jalili Dehkharghani, Li Hsiang Lin

Faculty Publications

Studying migration patterns driven by extreme environmental events is crucial for building a sustainable society and stable economy. Motivated by a real dataset about human migrations, this paper develops a transformed varying coefficient model for origin and destination (OD) regression to elucidate the complex associations of migration patterns with spatio-temporal dependencies and socioeconomic factors. Existing studies often overlook the dynamic effects of these factors in OD regression. Furthermore, with the increasing ease of collecting OD data, the scale of current OD regression data is typically large, necessitating the development of methods for efficiently fitting large-scale migration data. We address the …

Unveiling The Nexus Between Digital Monitoring And Experiences Of Intimate Partner Violence In Romantic Relationships, Caley Hewitt, Fanny A. Ramirez, Anna Gjika

Faculty Publications

Using survey data from a sample of 378 women who live in the United States and self-identify as either Black or Latinx, this study explores predictors of women’s digital monitoring practices in intimate relationships in the context of intimate partner violence (IPV). We use literature about surveillance, monitoring, and IPV to frame our study. Our results show three significant instances that influence the odds of monitoring a romantic partner: (1) past experiences with digital abuse, (2) past experiences with offline psychological abuse, and (3) age, with younger women having increased odds of engaging in digital monitoring compared to older women. …

How Financial Aid Affects The Odds Of Study Abroad Participation For Students Of Color, Patrick Newcomb

LSU Doctoral Dissertations

Prior research has shown that studying abroad provides students with enriching, diverse educational experiences with positive personal, academic, and professional outcomes. Despite the benefits, only a small portion of American higher education students participate in study abroad programs. Students of color disproportionately study abroad at lower rates than White students. Since cost is often cited as the primary barrier preventing education abroad, this study examined the types of financial aid associated with study abroad access and participation.

This study used data from the National Postsecondary Student Aid Study, which is a nationwide dataset designed to represent the makeup of institutions …

Approximations Of Koopman Operator Semigroups, Ibrahem Al Jabea

LSU Doctoral Dissertations

The main purpose of this dissertation is to study approximation methods for nonlinear systems using Bernhard Koopman's Global Linearization Method or Sophus Lie's method of continuous transformation groups. This approach enables the application of linear semigroup methods to a nonlinear system by focusing on the dynamics of the observables of the states, rather than directly studying the dynamics of the states. In this dissertation, we studied the pointwise semigroup and introduce the modified space $C_m(\Omega)$ and the modified Koopman-Lie semigroups. We use a splitting operator and outline a systematic approach for approximating the pointwise Koopman-Lie semigroup flows \begin{equation*} t\to T(t)g(x) …

19ne Excited States In Explosive Nucleosynthesis, Khang Pham

LSU Doctoral Dissertations

Classical novae and Type I X-ray bursts are stellar explosions that occur in binary systems, where nuclear reactions involving ¹⁹Ne play a crucial role in nucleosynthesis. In novae, the destruction of ¹⁸F via the ¹⁸F(p,alpha)¹⁵O reaction significantly affects the amount of ¹⁸F remaining in the ejecta, directly influencing the detectability of predicted 511-keV gamma rays. However, discrepancies between observed and predicted ¹⁸F abundances highlight uncertainties in the reaction rates, primarily due to unknown properties of resonances in the compound nucleus ¹⁹Ne. In Type I X-ray bursts, the ¹⁵O(alpha,gamma)¹⁹Ne reaction …

Unavoidable Immersions And Topological Minors Of K-Edge-Connected Graphs, Brittian Qualls

LSU Doctoral Dissertations

In this work, we present results concerning the unavoidable structures in large and infinite k-edge-connected graphs. These results are inspired by the classical result of Ramsey, who proved that for every positive integer r, every sufficiently large graph contains as an induced subgraph either K_r or $\overline{K_r}$. We consider different graph containment relations, focusing primarily on the immersion relation. In the case of finite graphs, we provide the unavoidable immersions of 4-edge-connected graphs and prove that linear edge-connectivity suffices to immerse the graph C_t,r.

This dissertation also considers infinite graphs. We present the …

Optical Spring Tracking For Enhancing Quantum-Limited Interferometers, Scott M. Aronson

LSU Doctoral Dissertations

Gravitational waves were first predicted by Albert Einstein in 1916. Calculations in the 1970s by Rainer Weiss showed an interferometer of sufficient size could realistically detect gravitational waves, which led to a grant by the National Science Foundation (NSF). With steady progress and over decades of funding by the NSF, the construction of two full scale 4km interferometers was approved and began construction in 1994. This project, coined LIGO the Laser Interferometer Gravitational-wave Observatory, came to be a worldwide collaboration of scientists dedicated to the discovery and study of gravitational waves. In 2015, both LIGO detectors detected a coincident inspiral …

Understanding The Experiences Of Biology Teachers During The Covid-19 Pandemic, Amber R. Collins

LSU Doctoral Dissertations

ABSTRACT

The 2020 COVID-19 Pandemic has caused the world to focus on the transition of learning environments that are more digital and virtual than any other time in educational history. Schools all over the world were required to adjust not only the mode of instruction, such as in virtual, hybrid, or in-person, but also create guidelines and procedures that reduce the amount of interaction between the teacher and the student (Garbe, Ogurlu, Uzeyir, & Cook, 2020). The research questions that guided this study were: 1) What are the experiences of five Biology teachers during the COVID-19 pandemic in transitioning to …

Assessing Groundwater Availability And Land Subsidence Risk Associated With Anthropogenic Activities In A Complex Aquifer System, Aya Bakr Attya Mohamed

LSU Doctoral Dissertations

The Southern Hills aquifer system (SHAS) is the primary source of water in the Capital area of Louisiana. However, the overexploitation of freshwater-bearing aquifers and the presence of two active faults, the BR fault and the DSS fault, have resulted in groundwater depletion, saltwater intrusion, and increased the risk of land surface subsidence. Such critical issues pose substantial threats to groundwater availability and exert detrimental effects on the environment and urban infrastructures. This dissertation presents a comprehensive investigation of the SHAS for recognizing the consequences of groundwater depletion and its potential long-term impacts on groundwater availability and land stability. A …

Quantitative Risk Analysis For Elections, George A. Buras

LSU Master's Theses

This paper examines risk analysis and risk management in the field of election security. The purpose of this paper is not to enumerate risks to election security or explain how they might be mitigated, but rather to understand and improve how we measure and communicate those risks.

First, I contextualize election security risks by establishing what it means for an election to be secure and I give an overview of the types of events that might threaten election security. Then, I explore different methods that we can use to model electoral risks. Existing resources for managing electoral risks use qualitative …

On Regularity And Convergence Of Solutions To The Boltzmann-Enskog Equations, Christian Ennis

LSU Doctoral Dissertations

The Boltzmann equation describes the time evolution of the density function in position-velocity space for a classical particle subjected to possible collisions by other particles in a diluted gas that expands in vacuum for a given initial distribution. While many authors have studied the probabilistic interpretation of the spatially homogeneous Boltzmann equation, there is a dearth of articles on the stochastic framework of the full (that is, spatially inhomogeneous) Boltzmann equation. In this thesis, we examine a stochastic process, developed by S. Albevario, B. Ruediger, and P. Sundar, whose law is a weak solution to a mollified Boltzmann equation. This …

Quaternary Subsurface Characterization Of The Mississippi River Valley Alluvial Aquifer: Insights From Interval Kriging And Airborne Em-Borehole Data Integration, Yuqi Song

LSU Doctoral Dissertations

The Pleistocene period significantly contributed to the formation of alluvial aquifer worldwide. These productive aquifers are crucial for domestic, industrial, and agricultural water supplies. The Mississippi River Valley alluvial aquifer (MRVA), a principal aquifer in the U.S., is crucial for national food security and global agricultural supply. This study aims to characterize the subsurface architecture of the MRVA, thereby enhancing fundamental understanding of sedimentological processes involved in the genesis of glacio-fluvial aquifers worldwide. The research objectives are threefold: (1) to provide a detailed characterization of the MRVA; (2) to develop 3D geostatistical methods for geological modeling; and (3) to develop …

On Unavoidable Infinite Hypergraphs, Samuel Weiner

LSU Doctoral Dissertations

Ramsey's Theorem states that every infinite graph contains either K_∞ or $\overline{K_∞}$ as an induced subgraph. For this reason, K_∞ and $\overline{K_∞}$ are often referred to as the unavoidable infinite graphs. Many similar results have characterized the unavoidable members for various classes of infinite graphs; perhaps the most notable of these is König's Infinity Lemma, which states that every infinite, connected, locally finite graph contains a ray as an induced subgraph. From these findings, one can easily deduce that every infinite, connected graph contains an infinite clique, star, or ray as an induced subgraph; …

Explicit Modularity And Moments For Certain Hypergeometric Character Sums, Brian Grove

LSU Doctoral Dissertations

A great deal of progress in number theory throughout history has been motivated by trying to solve equations. One of the most famous challenges is to show there are no positive integer solutions to $x^{n}+y^{n} = z^{n}$ for $n > 2$, posed by Fermat around 1637. Special cases, such as the $n = 3$ and $n = 4$ cases, can be established using various algebraic manipulations. However, a general solution was elusive until the late 1990s when the combined work of Wiles \cite{Wiles} and Taylor--Wiles \cite{TaylorWiles} give a full proof.

One of the key insights used in proving Fermat's conjecture involves …

Evaluating Biotic Effecrs Associated With The Paleocene-Eocene Thermal Maximum In Mississippi And Alabama: A Palynological And Biostratigraphic Study Of Amoco's Legacy Samples, Sarah Fortin Bancroft

LSU Master's Theses

The Paleocene-Eocene Thermal Maximum (PETM) was a ~200 ka period of rapid global warming in the earliest Eocene (~56 Ma) involving a roughly 7 °C rise in atmospheric and sea-surface temperatures. The Gulf of Mexico Wilcox Group contains very well-preserved terrestrial and deltaic sediments that contain exploitable hydrocarbons . The Wilcox Group’s Paleocene Tuscahoma and Eocene Hatchetigbee Formations have been roughly dated with calcareous and planktonic foraminiferal assemblages by AMOCO; however, the precise ages of these formations, their palynological assemblages, and their paleo-depositional geosystems are an area of active research.

Through a high-resolution palynological analysis, this study assesses the depositional …

Stochastic Analysis And White Noise Calculus Of Nonlinear Wave Equations With Application To Laser Generation And Propagation, Sivaguru S. Sritharan, Saba Mudaliar

Journal of Stochastic Analysis

No abstract provided.

Social Stories To Shape Impulsive Behaviors To Increase Self-Regulation In Preschoolers, Caroline Claire Hargrave

LSU Master's Theses

ABSTRACT

BACKGROUND: Students need to be able to self-regulate their behavior within the classroom, thus not interrupting instruction and keeping the classroom running smoothly. Self-regulation is a critical skill children need to succeed in multiple aspects of life. Poor self-regulation skills can lead to challenges academically as well as socially. Contrary to self-regulation is impulsivity, which surrounds not thinking before doing. Impulsivity is a common factor seen within the preschool setting, which surrounds multiple behavior variations deemed unsuitable for classroom learning. Previous research indicates that social stories can be implemented within the classroom to decrease inappropriate behaviors in preschoolers with …

The Boltzmann-Enskog Equation With Brownian Forcing, Aurora Wallace

LSU Doctoral Dissertations

Interacting particle systems (IPS) are used to rigorously derive partial differential equations modeling macroscopic behavior given by systems of stochastic differential equa- tions in physics, biology, and other sciences. These systems model the time evolution of n interacting particles with desired dynamics. In the n-system studied here, only two parti- cles may interact at a time (binary collisions). The particles are exchangeable; that is, the ordering of the particles does not play a role, and the interaction between the ith particle and the jth particle models an elastic collision. In this thesis, we use the method of inter- acting particle …