Digital Commons Network^™

Elucidation Of A Role In Biofilm Production For The Tyrosine Catabolism Pathway In Vibrio Cholerae And Analysis Of Reversible Phase Variation In Vibrio Vulnificus, Aheli S. Mukerji

LSU Doctoral Dissertations

Biofilms produced by the cholera pathogen Vibrio cholerae not only enhance its ability to survive in the environment but also allow pathogenic success of the bacterium. This organism also undergoes phase variation, switching between smooth and rugose colonial phenotypes, the latter forming much more vibrio polysaccharide (VPS) resulting in more robust biofilms and subsequently having an increased level of persistence. In a previous study, many genes were found to be upregulated in the transition from the smooth to the rugose phenotype. Here, several of these upregulated genes were investigated for their potential role in biofilm production, and an additional gene, …

Magnetic Field Enabled Assembly And Propulsion Of Colloidal Particles In A Magnetic Medium, Hashir M. Gauri

LSU Doctoral Dissertations

Colloidal particles are nano/micro meter-sized particles dispersed in a fluid medium and serve as diverse building blocks for assembling complex structures. The ease of tunability of the shape, size, and interparticle interactions of colloidal particles facilitates their assembly into rich structures and phases that mirror the assembly process of atomic systems. Often regarded as "big atoms" colloidal particles provide an ideal model system for investigating complex phenomena in condensed matter, such as crystallization and nucleation. While the assembly of colloids under thermodynamic equilibrium has been extensively studied, recent interest has shifted toward exploring colloids in non-equilibrium conditions to create dynamic …

Predictive Indicators For Graduation Upon Acceptance Into A Naacls-Approved Medical Laboratory Science Program, Warren Hovis

LSU Doctoral Dissertations

The primary purpose of this study was to determine the influence of selected academic and personal demographic characteristics on student success at a NAACLS-accredited medical laboratory science program in the southern portion of the United States.

Both academic and demographic categories were selected on students who entered the medical laboratory science program from 2014 to 2019 (pre-COVID). The sanitized, archived data set was provided by the MLS department and the registrar and student affairs office at the participating school. The extant data set contained academic and demographic variables, collected over a five-year period, of initially over 170 accepted MLS students. …

Stream Fish Assemblage Dynamics And Barriers To Aquatic Connectivity In The Ichawaynochaway Creek Watershed, Georgia, Usa, Jake R. Duhé

LSU Master's Theses

Stream fishes in the southeastern United States are adapted to hydrological disturbances such as droughts. However, this region is projected to experience increasingly frequent and severe disturbances that will elevate water demands given increasing agricultural and urban development. Further, road-stream crossings (RSCs) are abundant features in these streams that can exacerbate drought-mediated stream fragmentation and impede movements by many aquatic organisms, including fishes, when poorly constructed. These compounding effects may adversely affect the diversity and abundances of resident stream fishes, but their interactions remain poorly understood, warranting rigorous testing of how droughts and RSCs influence stream fish dynamics. I assessed …

Global Database For Naturally Occurring Radionuclides Associated With Offshore Oil And Gas Production, Ziran Wei, Songjie He, Stephanie Sharuga, Kanchan Maiti

Faculty Publications

This study compiles a comprehensive dataset on the occurrence, distribution, and potential impacts of Naturally Occurring Radionuclides (NORMs) near offshore oil and gas platforms. It encompasses data, including activities (Bq/l) and exposure levels (Msv), derived from various environmental matrices. A particular emphasis is placed on petroleum products and waste, such as produced water, scales, and sludges. The dataset contributes to a better understanding of the distribution of NORM wastes in marine environments, informs future radiological safety standards, contributes to the formulation of regulatory policies, and facilitates the design of mitigation strategies. The information—literature and data from five continents over the …

Water Exposure Time Distributions Controlled By Freshwater Releases In A Semi-Enclosed Estuary, Caitlin R.R. Turner, Matthew Hiatt

Faculty Publications

Freshwater diversions manage water shortages, salinity, and control floodwater by redirecting river flows; however, their full ecological and hydrological impact remains unknown. This study examines the Lake Pontchartrain Estuary in Louisiana using a hydrodynamic model and Lagrangian particle tracking to assess how diversion operations (open, closed) and tributary discharge levels (low, median, high) influence water exposure time—the cumulative duration water remains in a domain, including re-entry. Exposure time was analyzed based on the time required for 50%, 75%, and 90% of released particles ((Formula presented.), (Formula presented.), and (Formula presented.)) to leave a defined region of interest (ROI). Results show …

Metabolic And Physiological Regulation In C. Elegans: Insights Into Sperm Activation And Peroxisome-Mediated Longevity, Yash Flora

LSU Doctoral Dissertations

Organelle dynamics lie at the heart of cellular signaling and metabolic regulation, orchestrating physiological processes such as reproduction and aging across the lifespan. In this dissertation, I investigate how organelle-based signaling coordinates sperm activation and modulates organismal aging in the nematode Caenorhabditis elegans. I identify SPIN-4, a previously uncharacterized Spinster family transporter, as a key regulator of spermiogenesis. SPIN-4 is strongly expressed in developing sperm, localizes to the plasma membrane, and promotes sperm activation by facilitating the export of sphingosine-1-phosphate (S1P). Loss of spin-4 results in defective pseudopod formation, reduced motility, and compromised fertility, phenotypes that can be rescued …

Weather Impacts On Specialty Fruit Wholesale Prices, Oladayo Daniel Oluleye

LSU Master's Theses

This article investigates the relationship between temperature and precipitation variability and wholesale specialty fruit prices in the United States. Using fixed-effects panel regression and a comprehensive dataset of monthly price observations across ten major U.S. wholesale markets (Atlanta, Baltimore, Boston, Chicago, Detroit, Los Angeles, Miami, New York, Philadelphia and San Francisco) from 2000 to 2019, we examine how weather fluctuations affect wholesale market prices for five fruits including apples, avocados, grapes, oranges, and strawberries. Our analysis categorizes temperature into discrete bins representing the number of days per month within specific temperature ranges. The results show that extreme temperatures, particularly above …

Citizen Perceptions On The Use, Management And Availability Of Green Spaces In A Mediterranean Region, Daniel Jato-Spino, Fabio Capra-Ribeiro, Vanessa Moscardo, Laura Gallardo

Faculty Publications

Green spaces (GS) are vital for environmental sustainability and public well-being. Understanding public perceptions of GS can promote their distribution aligned with citizens’ preferences. This study explores the alignment between perceptions of GS use, management and availability, captured via a questionnaire in the Valencian Community (Spain), with the objective reality determined through Geographic Information Systems (GIS). Data were collected from 94 participants, with 72 % using GS for relaxation, 54 % for physical exercise and 51 % for walking. Most respondents (78 %) preferred natural reserves as their primary type of GS. While 38 % believed GS were equitably distributed, …

Intersectionality And Experiences With Mental Health Care: Transgender And Gender Diverse Autistic Adults, Megan Callahan

LSU Doctoral Dissertations

Current prevalence rates of autism spectrum disorder (ASD) in transgender and gender diverse (TGD) populations range between 4 and 13% (Thrower et al., 2020). Studies into autistic TGD individuals’ experiences with healthcare have primarily collected qualitative data, identifying themes including barriers to healthcare, invalidation of both autistic and TGD identities, difficulty finding competent providers, limited support and resources, and refusal of care (Cooper et al., 2022; Maroney & Horne, 2022; Hall et al., 2020). N = 3094 self-identified TGD adults completed the 2017 TransLifeline Mental Health Survey, a collaborative effort between the National LGBTQ Task Force and the TransLifeline, which …

Stomach Content And Stable Isotope Analysis Of Invasive Lionfish (Pterois Volitans) In The Florida Keys, Emily E. Shallow, Cassandra N. Glaspie, Michael J. Polito, Mitchell S. Lovell

Faculty Publications

The invasive red lionfish, Pterois volitans, plays a unique role in seagrass and reef ecosystems, where it functions as a top predator and competitor for both food and shelter. Given the ubiquitous distribution of lionfish in the Gulf of Mexico and Caribbean basins, their species provides an excellent opportunity to understand how an invasive predator's diet and primary energy pathways change as a function of size and habitat type. To investigate these patterns, we studied lionfish from a mosaic of deep reef, shallow patch reef, and seagrass bed habitats in the Florida Keys using stomach contents and stable isotope analysis …

Enhancing Photosynthesis Under Salt Stress Via Directed Evolution In Cyanobacteria, Zhenxiong Jiang, Khondokar Nowshin Islam, Malory Wolfe, Michael O'Connell, Dykia Williams, Ashley Florance, David J. Vinyard, Xiaohui Zhang, Maxwell Brenner, Andor J. Kiss, Xianhua Liu, Xin Wang

Faculty Publications

A key aspect of enhancing photosynthesis is improving the kinetics of photochemical quenching recovery following environmental perturbation or stress. Salt stress exacerbates high light stress in cyanobacteria and leads to severe yield losses in crop plants. Genetic traits that confer salt tolerance without compromising photosynthetic performance are essential for improving photosynthesis under these conditions. Here, we applied accelerated evolution in Synechococcus elongatus PCC 7942 by conditionally suppressing its methyl-directed mismatch repair system to obtain beneficial genetic traits for enhanced photosynthesis under salt stress. We screened over 10,000 mutants and isolated 8 strains with increased biomass or sucrose productivity under salt …

Interfacial Phenomena Of Plastics: From Surface Modifications To Environmental Impacts, Kennedy Guillot

LSU Doctoral Dissertations

Plastic is a ubiquitous part of everyday life since its introduction in the previous century. Global production continues to exponentially increase, establishing plastics as one of the most dominant materials in modern manufacturing. Within the scope of academia, plastic is essential due to its low cost and sterility, particularly for minimizing contamination. Beyond the laboratory, plastic use spans numerous industries, and its use and disposal has since raised many environmental concerns. Once valued for its durability, plastics now pollute the environment in landfills and natural ecosystems. In recent decades, the consequences of this pollution have been investigated, yet the full …

Exploring The Benefits Of A Virtual Reality Positive Psychological Intervention For Older Adults In Senior Living Communities, Christopher Reed

LSU Doctoral Dissertations

The majority of psychological research has followed a disease model focusing on how we reduce factors associated with psychopathology. In the last few decades there has been a push to explore positive psychological traits as an avenue for intervention by fostering traits we already possess. Most of these interventions have targeted mental health across the life span with fewer examining their efficacy on cognitive change with even fewer utilizing immersive technologies like virtual reality. By 2050 over 20% of the world’s population will be over the age of 60 and with this aging population rates of neurocognitive disorders will increase. …

Assessing Niche Differences Across The Dwarf Salamander Species Complex Of The Southeast Us, Sarah Roy

LSU Master's Theses

Characterizing niche differences in closely related species can provide valuable insights into the extent of ecological divergence between species, and the potential evolutionary processes behind speciation. This study builds the first ecological niche models for the Eurycea dwarf salamander species complex, which includes five species with varying distributions across the southeastern United States. Ecological niche models (ENMs) were built for each species using the machine-learning algorithm, MaxEnt. We used pairwise niche overlap analyses and statistical validation techniques to investigate potential ecological drivers behind species divergence and the degree of niche overlap among the five Eurycea species. We found an overall …

From Decriminalization To Social Legitimization: The Lived Experiences Of Non-Conforming Individuals In India, Heeya Datta

LSU Doctoral Dissertations

This dissertation explores how queer and non-conforming individuals in urban India navigate, resist, and reimagine dominant norms of kinship, intimacy, and family. Drawing on 18 in-depth interviews, it examines the lived experiences of LGBTQ+ individuals in the aftermath of legal reforms such as the decriminalization of Section 377 and the Transgender Persons (Protection of Rights) Act. While these reforms mark symbolic progress, queer individuals continue to face social stigma, legal exclusions, and familial rejection. The study is divided into three chapters: the first analyzes the dual role of homosociality as both a space of refuge and constraint; the second investigates …

Enduring Words: Resistance Through Sculptural Libraries, Alex C. Jacobs

LSU Master's Theses

Enduring Words: Resistance Through Sculptural Libraries is a thesis exhibition that challenges book censorship by transforming reading into a public and defiant act. Through direct sculptural interventions, the exhibition confronts cultural erasure, questions who controls the literature we consume, and highlights the role of art in safeguarding contested knowledge. This thesis focuses on a current body of exhibited sculptural works that embody the tension between access and erasure. These installations engage with the viewer by using a lighthouse built of books and a speech-bubble-shaped library embedded with censored texts. They do not quietly mourn the suppression of knowledge; they confront …

Atrapado En Limbo: Fronteras, Anthropologists, And Translation In Contexts Of The Missing And Unidentified At The México-Us Border, Aliya M. Godoy

LSU Master's Theses

The Missing Migrants Project reports that in the past 11 years, 11,138 missing migrants have been recorded in the Americas, with 6,512 of those migrants situated at the México-United States (US) border (Migration Within the Americas, n.d.). The crisis of missing and unidentified migrants at the México-US border is a topic of great discussion in the field of anthropology, and specifically in discourses of humanitarian forensic anthropological work. This research addresses the crisis at the border, expanding on the scholarship of family agency and language barriers between Spanish-speaking communities and medicolegal actors by investigating the role of anthropologists …

Mate Choice And Movement Ecology Of Plegadis Ibis In Louisiana, Ryan T. Klutts

LSU Master's Theses

In 1817, George Ord documented the first North American records of Glossy Ibis (Plegadis falcinellus), a species native to the Old World. Over the next 200 years, Glossy Ibis expanded its breeding range to include the Atlantic coast to southernmost Florida and thence up the Gulf coast to eastern Texas. Forty-five to 75 years ago, its range expansion brought it into secondary contact with White-faced Ibis (P. chihi) in Louisiana, a native species whose breeding range includes freshwater wetlands in Louisiana and eastern Texas. Hybridization between the two species resulted in a large hybrid zone in southern Louisiana, providing an …

A Phylogenomic Investigation Of The Historical Biogeography Of Livebearers (Cyprinodontiformes: Poeciliidae), Sheila Rodríguez Machado

LSU Doctoral Dissertations

The Neotropics contain several biodiversity hotspots and harbor the highest diversity of freshwater fishes globally. Yet, recognizing the patterns and processes driving this richness remains a challenge. Similarly, all groups and subregions have not received the same attention, especially in the genomics era. Addressing these knowledge gaps will help us to better understand the region’s evolutionary and biogeographic complexity. The goal of this dissertation is to examine phylogenetic and biogeographic patterns of Neotropical freshwater fishes, with emphasis on the Greater Antilles, across multiple taxonomic and geographic scales. To achieve this goal, I generated a genomic dataset of hundreds of ultraconserved …

Use Of Margins Around Small Brain Metastasis Improves Specificity Of Evaluation Methods For Stereotactic Radiosurgery Treatment Plans, Purity Kemunto Bundi

LSU Master's Theses

Purpose: To reduce the high false positive rates (FPRs ≥ 46%) from the evaluation of Gamma Knife stereotactic radiosurgery (SRS) treatment plans for small brain metastases. Specifically, we modified two evaluation indices, Treated Volume Ratio (TVR) and Gradient Index (GI), which exhibited FPRs exceeding 84%. A false positive result incorrectly indicates that an acceptable plan, as determined by a medical physicist and a radiation oncologist, is inacceptable.

Methods: This study utilized training and validation datasets from Gamma Knife treatment plans from The University of Texas MD Anderson Cancer Center (MDACC) and Mary Bird Perkins Cancer Center (MBPCC). Data included doses, …

Connections, Peter Froehlich

LSU Master's Theses

A definitive shift in American social interaction has been taking place far longer than most realize. It is easy to point the finger at the prevalence of technology and social media, this has been a trend that has been going on since the mid to late twentieth century. Stemming from changes in design, the breakdown of scheduled social outlets, and shifts in technology have led to what some writers and sociologists are calling “The Anti-Social Century.”

Working through a making practice to promote the building of connections through social interaction, three different types of spaces were targeted for the exploration …

Road Rage Or Road Cage: A Study Of The Ecological Impacts Of Roads On Wildlife Corridors And The Resultant Habitat Fragmentation, Addie Bagot

Design Research

As global road networks continue to expand, the resulting habitat fragmentation poses a significant threat to wildlife populations and ecological connectivity. In the United States, wildlife-vehicle collisions (WVCs) account for approximately 10 million animal deaths and 40,000 human fatalities annually, with incidents increasing by 50% over the past 15 years. This research investigates the ecological impacts of transportation infrastructure through a case study of Interstate 10 in Louisiana, specifically a 15-mile segment between Sorrento and LaPlace that cuts through the Maurepas Swamp Wildlife Management Area. This forested wetland, home to a rich diversity of species including the American alligator, has …

Nonnative Species Richness And Dominance Reveal Differing Support For Invasion Theory At A Continental Extent, Lily M. Thompson, William K. Annis, Stephen R. Midway, Julian D. Olden, Brandon K. Peoples

Faculty Publications

Aim: Empirical tests of conceptual hypotheses describing species invasions often differ depending on the spatial scale (spatial resolution and extent of study area) at which they were conducted. Some of this disparity may arise from tradeoffs in data quality necessitating the use of different indices of community invadedness among scales. Local-scale studies typically use fine-resolution, descriptive measures of community invadedness (‘dominance’, the proportion nonnative individuals) at limited spatial extents, while macroscale studies often aggregate datasets to cover large spatial extents but use coarser spatial resolution and less descriptive indices (nonnative species richness). We investigated the consequences of using different indices …

Reef Fish Movement And Community Assemblages Associated With A Newly Deployed Artificial Reef, Jade M. Carver, Brett J. Falterman, Stephen R. Midway, Christian Walker, Creed C. Branham, Michael A. Dance

Faculty Publications

Artificial reefs provide critical habitat for fish in areas lacking benthic structure, yet our understanding of how artificial reefs function and develop is limited. Here, changes in fish community assemblages were monitored using baited remote underwater video (BRUV) surveys before and after a new artificial reef was deployed in the northern Gulf of Mexico. Movement of red snapper (Lutjanus campechanus) and gray snapper (Lutjanus griseus) between nearby oil and gas platforms (n = 3) and the new artificial reef was examined using acoustic telemetry, and residency was calculated for fish associated with both structure types. Fish community development at the …

Shielding Resources For Four Common Radiopharmaceuticals Utilized For Imaging And Therapy: Tc-99m, F-18, I-131, And Lu-177, Michael Oumano, Richard Wendt, James Botti, Nathan Busse, David Hintenlang, Stephanie Leon, Kevin Little, Melissa Martin, Richard Massoth, Kenneth Matthews, Rameshwar Prasad, Sharon White, Jessica Clements

Faculty Publications

Introduction: The use of radioactive materials in the United States has been tightly regulated by the Nuclear Regulatory Commission and other entities for many decades. In 2015, however, the Joint Commission began to require hospital-based nuclear medicine departments to conduct shielding designs and evaluations for radioactive material areas, mirroring established x-ray practices. NCRP Report No. 147 guides diagnostic medical x-ray shielding, but obviously cannot be used alone for nuclear medicine applications. The rising demand for theranostic nuclear medicine shielding evaluations particularly necessitates updated focused guidance, the aim of this report. Methods: Monte Carlo simulations were conducted using GATE software to …

Testing For Normality In Regression Models: Mistakes Abound (But May Not Matter), Stephen Midway, J. Wilson White

Faculty Publications

This study examines the misuse of normality tests in linear regression within ecology and biology, focusing on common misconceptions. A bibliometric review found that over 70% of ecology papers and 90% of biology papers incorrectly applied normality tests to raw data instead of model residuals. To assess the impact of this error, we simulated datasets with normal, interval, and skewed distributions across various sample and effect sizes. We compared statistical power between two approaches: testing the whole dataset for normality (incorrect) versus testing model residuals (correct) to determine whether to use a parametric (t-test) or nonparametric (Mann-Whitney U test) method. …

Advanced Manufacturing Of Multifunctional Shape Memory Polymer Composites And Self-Healing Systems, John B. Konlan

LSU Doctoral Dissertations

The need for multifunctional light weight structures for engineering applications is on the rise. Multifunctional composites are desired because of their ability to combine multiple functionalities into one structure. The advantages of a high strength-to-weight ratio of multifunctional composites make them desirable and suitable for use in energy-efficient applications. Shape-memory polymers (SMPs) have attracted interest over the past several decades because of their multifunctional nature. They have found use in many applications such as aerospace, satellites, automobiles, textiles, and biomedical devices, where lightweight and multifunctionality are key. The self-healing nature of most SMPs makes them suitable for use in lightweight …

Fishing For Solutions: Compensation For Bycatch Reduction In The Gulf Of Mexico Shrimp Fishery, Daniel W. Harris

LSU Master's Theses

Bycatch, unintentionally caught non-target species, harms the profitability of commercial fishing operations and leads to death and injury of hundreds of thousands of marine animals per year. In the Gulf of Mexico, commercial shrimpers are required to use a bycatch reduction device (BRD). Better BRDs are being tested to further reduce bycatch. Because their use will not be mandatory, it is important to measure shrimper willingness to voluntarily adopt this conservation technology to predict potential fleet participation. This study uses contingent valuation to elicit commercial shrimpers’ willingness to accept compensation for using these new devices.

We employ an incentivized payment …

Proteomic Comparison Of Canine Gallbladder Versus Hepatic Neuroendocrine Neoplasms, Nadia Richmond

LSU Master's Theses

Hepatobiliary neuroendocrine neoplasms (HBNENs) are uncommon tumors in people and dogs, and the limited understanding of their biologic behavior often poses a diagnostic and prognostic challenge in the clinical setting. Though only a low number of cases have been described in dogs, there is evidence to indicate that primary gallbladder NENs may carry a more favorable prognosis compared to primary hepatic NENs. The emergence of liquid chromatography-mass spectrometry (LC-MS) in proteomic analysis has permitted large-scale analysis of neoplastic proteomes, allowing for better understanding of tumor pathophysiology while simultaneously enabling the rapid identification of protein biomarkers. Previous work in our laboratory …