Digital Commons Network^™

Distributed Load Testing By Modeling And Simulating User Behavior, Chester Ira Parrott

LSU Doctoral Dissertations

Modern human-machine systems such as microservices rely upon agile engineering practices which require changes to be tested and released more frequently than classically engineered systems. A critical step in the testing of such systems is the generation of realistic workloads or load testing. Generated workload emulates the expected behaviors of users and machines within a system under test in order to find potentially unknown failure states. Typical testing tools rely on static testing artifacts to generate realistic workload conditions. Such artifacts can be cumbersome and costly to maintain; however, even model-based alternatives can prevent adaptation to changes in a system …

Experiential Statistics: A Case Study In Favor Of Using Project-Based Learning To Advance Preliminary Statistics Content Knowledge In The Algebra I And Geometry Classroom, Trey Michael Earle

LSU Doctoral Dissertations

Preparing secondary students for college entrance requirements and the expectations of the job market, a market which is actively seeking the employees who are most qualified to take on jobs that require data analysis skills, is becoming increasingly important. Federal, state, and local education administrators and personnel must rewrite many of the general education curricula to incorporate data organization, collection, manipulation, application, and analysis in order to better prepare students for the expectations of college entrance and an ever-changing employment market. From a purely pedagogical standpoint, while traditional educational structure has been commonplace for decades in the United States, projects …

Identification Of Blda As A Major Regulator Of Virulence In The Sweetpotato Soil Rot Pathogen Streptomyces Ipomoeae And Characterization Of Distinct Clostridium Sweetpotato Soft Rot Isolates, Kuei-Ting Yang

LSU Doctoral Dissertations

Streptomyces ipomoeae is the causative agent of Streptomyces soil rot on sweetpotato, a disease characterized by extensive necrosis of both adventitious and storage roots. While Streptomyces potato scab pathogens produce a phytotoxin (thaxtomin A), which is induced in the presence of cellobiose and suberin, S. ipomoeae produces a less-modified, phytotoxin (thaxtomin C), whose inducer has not been identified. To investigate transcriptional regulation of thaxtomin C production, we inserted a promoter involved in thaxtomin C synthesis upstream of the gusA reporter in an S. ipomoeae strain. Reporter gene expression was significantly upregulated in the presence of size-fractionated sweetpotato extract (SPE). The …

Interface Engineering Of Materials For Energy And Biological Applications, Ardalan Chaichi

LSU Doctoral Dissertations

Interface interactions are generally classified into solid-liquid, solid-gas, solid-vacuum, liquid-gas, light-matter and electron-matter categories. Surface morphological studies as well as surface chemical reactions can be studied in various types of complex systems thanks to technological advances in materials characterization methods. By employing interface engineering in different applications, it is possible to control electrical, chemical, mechanical, optical and biological properties of materials. Accordingly, we have applied interface engineering in three different areas of energy materials, biomaterials and surface imaging. As a result, firstly, we have introduced a high intensity light flash-based method on engineered substrates for delamination of reduced graphene oxide …

Synthesis Of Structurally Diverse Molecular Scaffolds Enabled By Protected Oxyallyl Cations, Joshua Andrew Malone

LSU Doctoral Dissertations

This dissertation focuses on the synthesis of diverse molecular scaffolds through the use of protected oxyallyl cation intermediates. Chapter One provides background on the generation and applications of oxyallyl and silyloxyallyl cations, while focusing on the direct nucleophilic capture of theses intermediates to generate functionalized ketones and silylenolates. Chapter Two depicts our approach to generate six-membered silyloxyallyl cations through the use of mild Brønsted acid activation. Regioselective nucleophilic capture of these intermediates successfully produced diverse a,a’-substituted silylenol ethers enabled by polar solvent and residual water.

Chapter three details strategies to generate 1,4-dicarbonyl compounds, focusing on the capture of cationic intermediates …

Reinforcement Learning Approach For Inspect/Correct Tasks, Hoda Nasereddin

LSU Doctoral Dissertations

In this research, we focus on the application of reinforcement learning (RL) in automated agent tasks involving considerable target variability (i.e., characterized by stochastic distributions); in particular, learning of inspect/correct tasks. Examples include automated identification & correction of rivet failures in airplane maintenance procedures, and automated cleaning of surgical instruments in a hospital sterilization processing department. The location of defects and the corrective action to be taken for each varies from task episode. What needs to be learned are optimal stochastic strategies rather than optimization of any one single defect type and location. RL has been widely applied in robotics …

An Improved Foam Modeling Technique And Its Application To Petroleum Drilling And Production Practice, Yanfang Wang

LSU Doctoral Dissertations

Foam is one of the most common used multiphase fluid in Underbalanced Drilling (UBD) and Managed Pressure Drilling (MPD). Because of its low density, high capacity of lifting and carrying cuttings, low cost and compatibility with formations, foam has become more superior than the conventional drilling mud when depleted reservoir pressure, severe lost circulation, or unstable borehole are encountered. In general, the success of foam applications rely on the understanding of the fundamentals of foam rheology in downhole conditions.

Foam rheology has been studied for decades. Conventional foam rheological models such as Power Law, Bingham Plastic, Herschel-Bulkley to explain foam …

Machine Learning Based Applications For Data Visualization, Modeling, Control, And Optimization For Chemical And Biological Systems, Yan Ma

LSU Doctoral Dissertations

This dissertation report covers Yan Ma’s Ph.D. research with applicational studies of machine learning in manufacturing and biological systems. The research work mainly focuses on reaction modeling, optimization, and control using a deep learning-based approaches, and the work mainly concentrates on deep reinforcement learning (DRL). Yan Ma’s research also involves with data mining with bioinformatics. Large-scale data obtained in RNA-seq is analyzed using non-linear dimensionality reduction with Principal Component Analysis (PCA), t-Distributed Stochastic Neighbor Embedding (t-SNE), and Uniform Manifold Approximation and Projection (UMAP), followed by clustering analysis using k-Means and Hierarchical Density-Based Spatial Clustering with Noise (HDBSCAN). This report focuses …

Mixed Messages: Reading Contemporary U.S. Literature Of Biracial Girlhood, Candice Nicole Hale

LSU Doctoral Dissertations

The tragic mulatta character is no longer an accurate representation of biracial female characters in literature. This dissertation considers the vast history of the tragic mulatto genre and its tragic and mired representations of biracial women and how they are often portrayed in literature. Within a historical, legal, and political analysis, I highlight the ways perceptions, attitudes, and representations about biracial individuals have changed, so those same shifts should change in the literature. Because of the bourgeoning field of Critical Mixed Race Studies (CMRS), both scholars and authors are recasting and rewriting the narratives and discourses of mixed-race in the …

Experiences Of Transgender Men Who Joined National Pan-Hellenic Council Sororities Pre-Transition, Sydney Epps

LSU Doctoral Dissertations

The National Pan-Hellenic Council (NPHC) - affectionately known as The Divine Nine - are places of support and leadership development for students. However, these groups espouse traditional gender role themes that align with sexual orientation and gender rigidity. This paper explores how four NPHC members negotiate their identity as both nonbinary or transgender, and Greek. Using the narrative inquiry approach, the researcher will explore how sorority members who no longer identify as cisgender women are treated post-gender transition by other sorority members.

Fluid-Driven Fracture Initiation From Oil And Gas Wells Considering Lifetime Stresses, Andreas Michael

LSU Doctoral Dissertations

Fluid-driven fracture initiation from oil and gas wells is examined in detail. The dissertation covers three subtopics: drilling, completion (stimulations), and post-blowout capping-induced fracture initiation.

Drilling-induced tensile fractures (DITFs) are located in an azimuth orthogonal to wellbore breakouts and are observed from image logs obtained during drilling operations. Fully analytical criteria for the orientation of DITFs initiating from wells in porous, permeable media are derived considering fluid infiltration from a pressurized wellbore. DITF orientation (longitudinal or transverse-to-the-wellbore) is used to constrain the magnitude of the local maximum horizontal principal stress. The range of the possible stress states is indicated on …

Measurements And Mitigation Of Scattered Light Noise In Ligo, Corey Daniel Austin

LSU Doctoral Dissertations

The Advanced LIGO (aLIGO) detectors use 1064 nm lasers to measure the tiny fluctuations in spacetime that occur when gravitational waves pass through the earth. LIGO makes use of advanced coating methods and materials to limit the amount of light that scatters from the main beam, but some amount of light does scatter. This stray light can interact with surfaces inside the interferometer that are not seismically isolated and then recombine with the main beam, introducing excess noise into the gravitational wave channel. This thesis reviews the methods for modeling scattered light with ray tracing software and analytical models, for …

Molecular Mechanisms Of Boron Toxicity Tolerance In Plants, Guannan Wang

LSU Doctoral Dissertations

Boron toxicity is a worldwide agricultural problem that limits crop productivity and quality. However, our understanding on the genetic responses and adaption mechanisms to boron toxicity in plants is very limited. To address this gap in our knowledge, I compared boron stress-sensitive model, Arabidopsis thaliana and its stress-adapted relative Schrenkiella parvula to study how plants respond and adapt to excess boron at physiological, genomic, transcriptomic, and metabolic levels.

The overall project goal involved integration of multi-omics datasets to develop genome to phenome interpretations. To achieve this, I developed a python package, GOMCL, to facilitate the extraction of biologically meaningful information …

Deep-Ultraviolet Laser Ablation For Biomolecular Analysis, Oluwaremilekun Omowunmi Lawal

LSU Doctoral Dissertations

New sampling and ionization techniques were developed using a deep-ultraviolet (DUV) laser at 193 nm wavelength for analysis of large biomolecules. A micrometer spatial resolution DUV laser ablation and capture system was constructed to sample tissue biomolecules. The spot size measurements of the focused beam showed that subcellular spots with ca. 2 μm diameter can be readily achieved with this wavelength. To demonstrate the extraction of tissue biomolecules with the DUV laser, regions of tissue sections were ablated and captured for offline proteomic and genomic analysis. The proteomic studies revealed that the tissue proteins were ejected without fragmentation and that …

Sustainable Management Of Groundwater In Louisiana, Dependra Bhatta

LSU Doctoral Dissertations

The common property nature of the Mississippi River Alluvial Aquifer (MRAA) results in the formation of a cone of depression in the southern portion of the aquifer encompassing Concordia parish, Louisiana. Excessive groundwater withdrawal and the resulting cone of depression formation have caused some wells to go dry and others to be affected by saltwater intrusion. The depleting groundwater stock can be managed optimally using different groundwater management policies. The findings of this dissertation are relevant to both policymakers and researchers to understand the effects of policies to keep the aquifer sustainable.

My dissertation is written in a three-essay format. …

Structure And Dynamics Of Phospholipid Vesicles And The Dependence On Nanoscale Interactions With Molecules Of Varying Complexity, Lakshapathy Widanelage Judith Upeka De Mel

LSU Doctoral Dissertations

In this dissertation, molecular interactions and changes imposed by nano-scale structures on phospholipid vesicles were investigated. 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) large unilamellar vesicles (LUVs) were used as the model system. Understanding changes of the bilayer structure, interfacial properties, lipid dynamics, and self-assembly, allows bridging relationships between biological cell membrane structure and dynamics to cellular functionalities. For example, membrane curvature changes are linked to membrane protein functions, although the exact mechanisms of control are not yet understood. Moreover, the knowledge gained from vesicle models allows exploring novel strategies for drug delivery applications. To achieve this, DOPC LUVs were synthesized and characterized by a …

Sexually Dimorphic Oxytocin Receptor-Expressing Neurons In The Anteroventral Periventricular Nucleus Regulates Maternal Behavior, Kaustubh Sharma

LSU Doctoral Dissertations

The neurohypophysial hormone oxytocin is involved in the regulation of social behaviors, including social recognition, pair bonding, and sex-specific parental behaviors in a variety of species. Oxytocin triggers these social behaviors by binding to oxytocin receptors (OXTR) in various parts of the brain. Oxytocin-induced sex-typical behavior, therefore, suggests a sexual dimorphic distribution of OXTR in the brain. In recent years, the oxytocin system in the brain received tremendous attention as a potential pharmacological target for treatment of many psychiatric disorders, such as anxiety, autism spectrum disorders, and even sex-specific psychiatric disorder like postpartum depression (PPD). An important problem and a …

Computational Investigations Of Battery Electrolytes, Ke Li

LSU Doctoral Dissertations

In this dissertation, the structure and dynamics of battery electrolytes were investigated using atomistic molecular dynamics (MD) simulations. Battery electrolytes play a key role in transporting ions between the cathode and anode. The chemical stability and ionic conductivity of electrolytes influence battery performance. In order to design better electrolytes, one needs an understanding of the relationship between electrolyte structure, dynamics, and bulk properties. To bridge the gap between the macroscopic phenomenon and the hidden molecular physics, in the first project we focused on probing an ether-based electrolyte, chosen for its relevance in sodium-based batteries. Through studying the impact of concentration …

Quantifying Structure And Variation In Complex Phylogenetic Data, Genevieve Geraldine Mount

LSU Doctoral Dissertations

Identifying the source and structure of variation in nature is crucial to understanding fundamental aspects of evolution. Despite a recent plethora of genetic and morphological data, many interesting questions about the relationships between different groups remain unresolved. My dissertation evaluates three approaches for identifying and quantifying the variation within phylogenetic datasets. Characterizing variation within datasets and across analytical methods gives insight into biologically interesting characters, unusual evolutionary processes, and areas for model improvement.

Network-based community detection approaches offer a powerful tool to describe variation in phylogenetic signal across the genome (i.e., gene tree variation). In Chapter 2, I investigate the …

Evolution Of Green Blood In New Guinea Lizards: Phylogenomics, Biogeography, And Comparative Genomics, Zachary Rodriguez

LSU Doctoral Dissertations

Non-model organisms with evolutionary novelties and complex distributions can provide valuable insight into the mechanisms underlying biological diversity. Green blood is one of the most unusual vertebrate physiologies and has repeatedly evolved in lizards from the megadiverse island of New Guinea. An unusually high concentration of the toxic green bile pigment biliverdin causes the green coloration of these lizards' blood, muscles, and bones. This dissertation uncovered the complex history of this novel trait (Chapter 2), identified protein-coding sequences that underlie green blood in lizards (Chapter 3), and explored evolutionary processes that drive genetic diversity in high-elevation lizards. To accurately trace …

Leave It To The People: Position And Positioning Of Stakeholders In Top-Down Sustainable Development And Risk Reduction Frameworks From Global To Local Levels, Bethany Bille Garfield

LSU Doctoral Dissertations

Dissertation concerning design, contents, priorities, and outcomes of development and disaster risk reduction (DRR) global indicator frameworks. Historical review of United Nations (UN) multilateral agreements and organizational dynamics precedes analysis of indicator data reported for Sustainable Development Goal (SDG) targets shared by the 2015 Paris Agreement and Sendai Framework for Disaster Risk Reduction (SFDRR). Background on the planning of UN frameworks is considered along with results of indicator data analysis to identify actors and processes that steer the focus of frameworks hence influence selection of targets and indicators, and corresponding framework agendas. Fundamental flaws in resolution frameworks preventing global goal …

Crisis, Crisis, Read All About It! Investigating The Direct And Joint Effects Of Crisis Response Strategies, Crisis History And Strategic Actions On The Tone Of Media Coverage, Habiba Nefisa Alambo

LSU Doctoral Dissertations

Crisis management research has focused on how crisis stricken firms protect their reputation by communicating appropriate messages to evaluators and employing strategic actions that favorably shape public opinion about the stricken firm. Developing conversations have addressed how a firm’s crisis history may impact current crisis management efforts. However, little is known about how these factors jointly and directly influence what is said about a crisis stricken firm and subsequently impact evaluators’ perceptions.

Primarily guided by the tenets of attribution and situational crisis communication theories, I studied the interactive and main effects of crisis response strategies (accommodative, reframing and defensive), crisis …

Function, History, And Ecology In The Exceptional Radiation Of Murine Rodents, Jonathan Allen Nations

LSU Doctoral Dissertations

Life’s diversity is not spread evenly across all lineages, and this unevenness is thought to be due, in part, to a few interwoven factors: biogeographic history, the evolution of successful functional traits, and the ecological opportunity these traits afford. My dissertation focuses on the evolution of a species-rich and morphologically diverse clade of mammals, the murine rodents (Murinae; Muridae; Rodentia) to address 1) morphological adaptations associated with niche transition to arboreality 2) the effect of repeated ecological transitions on murine diversification, and 3) the role of atypical ecological niches in the assembly of hyperdiverse communities. My dissertation has revealed that …

College Expectation And Matriculation: High School Students Journey To Postsecondary, Sabrina Juanita Johnson

LSU Doctoral Dissertations

Racial group membership and social-economic status (SES) among academically talented students are recognized as powerful predictors of matriculation and college expectations. Moving or transitioning from high school to college is an essential pathway for success in life. Previous research suggests that college enrollment is correlated to resource opportunities available to students that they can access through their relationship with their parents, peers, school staff, teachers, and others.

These relationships are vital in increasing college matriculation by providing academic assistance, emotional support, psychological encouragement, relevant information, and guidance to students in the complex college application process.

College preparatory or outreach programs …

Incorporation Of Lignin In Natural And Synthetic Biomaterials To Alter Mechanical And Biochemical Properties For Enhanced Wound Healing, Jorge Alfonso Belgodere

LSU Doctoral Dissertations

It is estimated that chronic, non-healing wounds affect more than 6.5 million Americans annually, with an estimated healthcare cost beyond $14 billion. Here, we attempted to create composites of natural (collagen type I or gelatin-methacrylate) or synthetic (poly(ethylene glycol) polymers incorporating a natural plant component, lignin, to combat the costs and limitations current wound healing methods face. Three-dimensional matrices of collagen type I (Col I) are widely used in tissue engineering applications for its abundance in many tissues, bioactivity with many cell types, and excellent biocompatibility. Inspired by the structural role of lignin in plant tissue, we found that sodium …

University Faculty Design-Thinking Personas For Online Course Development: A Q Methodological Study, Jennifer Margaret Morrisette

LSU Doctoral Dissertations

To overcome the inherent complexities of planning and implementing effective online learning experiences at scale, it has been suggested that design-thinking tools and practices can be leveraged by faculty and collaborative support staff (e.g., instructional designers). However, little is known about what design-thinking approaches are perceived by faculty to be important to the online course design process, and what tools and practices might be prioritized or avoided given planning stage and individual context. Understanding these nuances would provide much needed insight to align support directly with faculty needs. This study used Q methodology to explore the subjective viewpoints of 20 …

Identification Of Novel Host Genes Required For Antiviral Immunity And Viral Genome Replication In C. Elegans, Fei Meng

LSU Doctoral Dissertations

RNA interference (RNAi) is a wide-spread gene silencing mechanism that control diverse biological functions and triggered by small interfering RNAs (siRNAs) processed from the viral genome or its replication intermediates. Mechanistic studies of antiviral RNAi in Caenorhabditis elegans has led to the identification of several critical factors involved in the process. As a result, whether antiviral RNAi requires additional novel genes remains to be an open question.

Viruses are intracellular parasites that rely on host products for reproduction. Disrupting their interaction with host factors can significantly compromise their replication and keep them under control. Thus, identification of host genes …

Nutraceuticals & Resistance Exercise Training:Effects On Rate Pressure Product--- An Index Of Myocardial Oxygen Consumption, Junhai Xu

LSU Doctoral Dissertations

The primary purpose of this dissertation was to investigate the acute effect of different REs on the heart, the effect of conventional RE on the heart in combination with nutraceuticals, through measuring rate pressure product (RPP). Three studies were conducted in this dissertation.

The first study was to examine the effect of volume-matched single-set and multiple-set leg press exercise on myocardial energy expenditure. Fourteen healthy untrained college students performed 4 sets of 10 repetitions or 40 repetitions of leg press exercise at 150% body weight on different days. Post-exercise RPP, RPP_diff, RPP_perc, and HR_perc for …

The Implications Of The American Symphonic Heritage In Contemporary Orchestral Modeling, Mathew Lee Ward

LSU Doctoral Dissertations

Disparate priorities between composers, performers, audiences, and institutions have created systemic issues in the sustainability and relevance of symphonic music in modern society. The purpose of this study is to explore the history of the symphonic heritage in the United States with the goal of forming solutions to contemporary issues in the sphere of classical symphonic music. With consideration for the breadth of repertoire, the genre of the symphony is the primary focus, with special attention given to under-represented and under-performed composers. The American symphony orchestra, nonexistent during the founding of the country, has become one of the greatest conduits …

Water-Energy Nexus: Studies On Salinity Gradient Energy Harvest And Desalination, Guangcai Tan

LSU Doctoral Dissertations

Water and energy are fundamentally linked, and both are important for the development of human society. The demand for renewable energy and freshwater are two global challenges in the 21^st century. Herein, a novel chloride-ion (Cl⁻) concentration flow cell (CFC) based on two symmetrical electrodes (BiCl₃, CoCl₂, VCl₃, or BiOCl) separately by a cation-exchange membrane was used as an efficient method to recover salinity gradient (SG) energy. The CFC with metal chloride electrodes (BiCl₃, CoCl₂, and VCl₃) was based on Cl⁻ extraction/insertion, and that …