Digital Commons Network^™

Modeling The Effects Of Temperature And Resource Quality On The Outcome Of Competition Between Aedes Aegypti And Aedes Albopictus And The Resulting Risk Of Vector-Borne Disease, Emma Beck, Lauren Beuerle, Patt Martin, Regan Stambaugh, Rebeca De Jesús Crespo, Michael A. Robert, Suzanne L. Robertson

Faculty Publications

The community composition of vectors and hosts plays a critical role in determining risk of vector-borne disease transmission. Aedes aegypti and Aedes albopictus, two mosquito species that both transmit the viruses that cause dengue, chikungunya, and Zika, share habitat requirements and compete for resources at the larval stage. Ae. albopictus is generally considered a better competitor under many conditions, while Ae. aegypti is able to tolerate higher temperatures and is generally a more competent vector for many pathogens. We develop a stage-structured ordinary differential equation model that incorporates competition between the juvenile stages of two mosquito populations. We incorporate experimental …

The Sensitivity Of Future Hydroclimate Projections To Topography And Large-Scale Dust Forcing In The Luquillo Mountains Of Eastern Puerto Rico, J. Preece, C. Johnson, T. Mote, P. Miller, M. Williams

Faculty Publications

Precipitation over Puerto Rico is expected to decline in coming decades, threatening an important source of surface water supply. However, earth system models neither resolve fine-scale orographic impacts nor the radiative effects of Saharan dust aerosols on precipitation over the island's mountains. Here, we use the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) to downscale global climate model projections to a convection-resolving 4-km resolution for both dust and no-dust scenarios. We compare the regional hydroclimate during three periods: historical (2014–2018), mid- (2045–2049) and end-21st century (2085–2089), using output from an RCP8.5 simulation of the Community Earth System Model, …

Binding Of A [2fe-2s] Cluster Drives Dimerization Of Ferric Uptake Regulator (Fur) In Escherichia Coli, Fatemeh Najafi, Aidan G. Purcell, Finbar H. Homes, Huangen Ding

Faculty Publications

The ferric uptake regulator (Fur) is a global transcription factor that reversibly binds an iron-sulfur [2Fe-2S] cluster via the cysteine residues (site 3) in response to elevation of intracellular free Fe content in Escherichia coli. Here, we report that when E. coli Fur is expressed in E. coli cells grown in M9 medium supplemented with Fe or zinc (Zn), purified Fur binds a [2Fe-2S] cluster or Zn(II), respectively. While apo-form Fur is a monomer and has no DNA-binding activity, both the [2Fe-2S] cluster-bound Fur and the Zn(II)-bound Fur are homodimers and have a similar binding activity for the DNA sequence …

Time Series Changes Of Surficial Sediments On Eastern Ship Shoal, Louisiana Shelf, Adam Gartelman, Kehui Xu, Brian J. Roberts, David Samuel Johnson, Madison Liotta

Faculty Publications

Ship Shoal, a large transgressive sand body on the Louisiana continental shelf, is a critical sediment source for coastal restoration. This study evaluates spatial and temporal variability in sediment grain size, percents organic matter (%OM), and carbonate (%CO3) across the shoal crest (REF), Caminada Dredge Pit (CAM), and Terrebonne Dredge Pit (TER). Sediment samples were collected between 2020 and 2022 using box cores and analyzed for grain size, %OM, and %CO3, with temporal and spatial patterns assessed through statistical comparisons, correlation analyses, and random forest regression models. Results show that dredged areas act as sinks for fine-grained, organic-rich sediments, with …

A Comparison Of Characteristics Of Infilling Sediments In Three Mud-Capped Dredge Pits On The Louisiana Continental Shelf, Wenqiang Zhang, Kehui Xu, Chaochen Jia, Adam Gartelman, Omar Alawneh, Navid Jafari, Colin Herke, Madison Liotta, Samuel J. Bentley

Faculty Publications

Due to high sedimentation rate up to ~1 m/year, mud-capped dredge pits (MCDP) are often considered natural laboratories for studying sedimentary processes, slope stability and the impacts of dredging activities on marine environments. Although many studies have been performed on the Louisiana shelf, there is a lack of high spatial resolution research covering the eastern, central and western Louisiana shelf to comprehensively investigate sediment infilling. Eighteen vibracores were collected from the Peveto Channel dredge pit (PC), Raccoon Island dredge pit (RI) and Sandy Point dredge pit (SP), and more than 1300 samples were analyzed to study the spatial variation in …

Recovery Of Benthic Macroinfauna Six Years After Dredging, David Samuel Johnson, Manisha Pant, Andrew Nemeth, Emelie Foster, Adam Gartelman, Stacy Calhoun-Grosch, Kehui Xu, Brian J. Roberts, James Nelson

Faculty Publications

In soft-sediment communities, benthic macroinfauna can recover quickly (sometimes < 1 year) from dredging. However, it’s unclear how recovery is influenced if dredging dramatically changes abiotic factors. We determined recovery of benthic macroinfauna from dredging on a sandy shoal (Ship Shoal, Louisiana, USA), six years after dredging. Because the dredged area infilled with mud instead of sand and changed local abiotic conditions, we hypothesized that the benthic community had not recovered. Our results support this hypothesis. Although the dredged community had, on average, 160% greater density and 170% greater macroinfaunal biomass than the reference community, these increases were driven by the opportunistic and seasonally variable dwarf clam, Mulinia lateralis. Community structure differed starkly between the regions. Haustoriid amphipods and amphioxus (Branchiostoma floridae) dominated the reference community. However, these taxa were largely absent from the dredged community, which was dominated by opportunistic species such as M. lateralis and the fringe-gilled mudworm Paraprionospio pinnata. Community differences were largely driven by bottom-water dissolved oxygen and sediment grain size. Our results suggest that the dredged areas are still in a transitional phase of recovery after six years – dominated by opportunistic, hypoxia-tolerant species. Our results suggest that abiotic factors such as grain size and hypoxia are important in structuring benthic communities and their recovery rates. Thus, to achieve faster recovery of the biological community, dredging should be conducted in a way that minimizes long-term impacts on abiotic conditions.

A Test Of The Abundant-Center Hypothesis For Stream Fishes, Matthew L.W. Zink, Brandon K. Peoples, Julian D. Olden, Lily M. Thompson, William K. Annis, Stephen R. Midway

Faculty Publications

The abundant-center hypothesis (ACH) provides a conceptual model for predicting range-wide distributions of species abundance, suggesting that abundance peaks in the center of the geographic range and declines towards range edges. Empirical studies testing the ACH and its subsequent derivations predominantly occurred in terrestrial systems and reported mixed support. Moreover, none of these models consider the possibility of multiple geographic areas of elevated abundance (which we refer to as ‘abundant cores'). Naturally dispersal limited species may exhibit multiple abundant cores, requiring refinement of the ACH. We used fish species abundances from 29 206 community monitoring surveys and weighted geospatial kernel …

Artificial Intelligence In Head And Neck Cancer: Towards Precision Medicine, Jacob Hagen, Logan Hornung, William Barham, Supratik Mukhopadhyay, Adam Bess, Kevin Contrera, Devraj Basu, Vlad Sandulache, Guillaume Spielmann, Sagar Kansara

Faculty Publications

Over the past 20 years, the capabilities of artificial intelligence (AI) have gained significant interest. While AI has been implemented to various degrees in several disciplines, its unique applications in head and neck cancer (HNC) remain underdeveloped. This narrative review examines the existing body of literature regarding the use of AI in HNC. Studies to date have demonstrated AI’s utility across multiple phases of the HNC treatment continuum. Despite its promise, integrating AI into clinical practice faces several challenges, including concerns about system integrity, generalizability, privacy, and bias. In this review, we address these challenges and offer insights into future …

Compound-Specific Isotope Records Of Dust Provenance And Hydroclimate In The North Pacific And Marginal Seas Of East Asia: Integrating N-Alkane Δ13c And Δd With Standardized Analytical Frameworks, Julian W. Traphagan

LSU Doctoral Dissertations

This dissertation presents advancements in compound-specific isotope analysis (CSIA) through methodological innovation and paleoclimate reconstruction in Central and East Asia. Utilizing plant wax n-alkanes from International Ocean Discovery Program (IODP) and Ocean Drilling Program (ODP) sediment cores, this research reconstructs atmospheric circulation shifts responding to tectonic evolution and climate transitions since the Late Miocene.

Chapter 1 investigates hydrogen isotope compositions (δD_wax) from IODP U1430 (Sea of Japan), ODP 886, and ODP 1208 (North Pacific) to trace dust provenance and hydroclimate changes since ~13 Ma. Results reveal persistently segmented source-to-sink systems: the Sea of Japan dominated by westerly …

Effects Of Cryoprotective And Mitochondrial Stabilizing Agents On Vitrified Bovine Oocytes, Allison Hoang

LSU Master's Theses

Oocyte vitrification success is highly dependent on cryoprotectant agent (CPA) choice as well as possible additives that could help preserve mitochondrial membrane potential (mMP), reactive oxygen species (ROS) production, and calcium homeostasis within the cell. It is a delicate balance between levels needed for proper oocyte function and activation and levels needed to induce apoptotic pathways. The results of oocyte cryopreservation determine the eventual oocyte viability and subsequent fertilization and embryo development.

In this study potential permeating cryoprotectant combinations were explored such as ethylene glycol (EG) and propylene glycol (PG) or EG in combination with dimethyl sulfoxide (DMSO). Also, the …

Subtropical Marine Cloud Brightening Suppresses The El Niño–Southern Oscillation, C. Xing, S. Stevenson, J. Fasullo, C. Harrison, C. Chen, J. Wan, J. Coupe, C. Pfleger

Faculty Publications

Stratospheric aerosol injection (SAI) and marine cloud brightening (MCB) are two proposed methods of compensating for greenhouse gas-induced warming by reflecting incoming solar radiation. However, their effects on the El Niño–Southern Oscillation (ENSO), a critical mode of climate variability, are poorly understood. Here we use ensembles of climate model simulations to show that deploying MCB in the subtropical eastern Pacific dramatically reduces ENSO amplitude by approximately 61%, while SAI has a negligible impact. MCB increases cloud albedo, which cools the subtropical eastern Pacific and triggers a loss of moist static energy. This cooling promotes atmospheric subsidence, dries the tropical Pacific, …

Novel Sequential Modeling Framework Improves Phytoplankton Biomass Predictions In Response To Multiple Environmental Stressors, Zhuyin Tong, Jiayu Guo, Yikai Liu, Lizhen Lin, Jixin Chen, Xin Liu, Bangqin Huang, Edward A. Laws, Wupeng Xiao

Faculty Publications

Understanding the impacts of multiple environmental stressors on phytoplankton biomass is crucial for predicting marine ecosystem responses under global climate change. This study employed a sequential modeling framework integrating principal component analysis, generalized additive models, and artificial neural networks to improve predictions of phytoplankton chlorophyll a concentrations in the Taiwan Strait. Analyzing a decadal dataset, we found that a 2°C rise in sea surface temperature and a 0.2 pH decline will each lead to an 11.3% reduction in chlorophyll a biomass, whereas nitrogen enrichment is expected to increase it by only 2.8%. The combined effects of these stressors will result …

Cell Death Helps To Stabilize Populations Of Prochlorococcus, P. Wang, E. A. Laws, C. Liang, X. Liu, J. Chen, Y. Zhong, C. Li, B. Huang

Faculty Publications

Prochlorococcus is one of the dominant phytoplankton species in tropical and subtropical pelagic marine ecosystems. To maintain its population equilibrium in oligotrophic waters, the dominant species Prochlorococcus requires high loss rates to offset its high abundance and growth rates. While theoretical frameworks recognize multiple loss processes for Prochlorococcus (viral lysis, environmental stress, programmed cell death), prevailing population studies attribute main mortality to grazing. This oversight stems from in situ data gaps of non-grazing mortality processes. In this study, we firstly formulated simple differential equations that took account of population losses due to both grazing and cell death. We then used …

Characterization Of The Role Of Rsd-6, A Tudor Domain Protein, In Antiviral Rnai Pathway In Caenorhabditis Elegans, Krishna Prasad Dahal

LSU Doctoral Dissertations

RNA interference (RNAi) triggered by virus produced dsRNA intermediate offers robust innate immunity against invading viruses in plants, insects and animals. Caenorhabditis elegans has been extensively used as a model organism to study host virus interaction. Recently, a forward genetic screen identified RNAi spreading deficient-6 (RSD-6), a Tudor domain protein, as a key component in antiviral RNAi pathway against Orsay virus in C. elegans but its contribution in the pathway remained unclear. Here, we generated a rsd-6 null allele using CRISPR-Cas9 genome editing, crossed it with other known RNAi mutants and analyzed Orsay virus replication in them and in combination …

Patterns And Processes Behind Secretive Marshbird Movement, Abundance, And Distribution Across Southeastern Louisiana, Leah Moran

LSU Doctoral Dissertations

Restoration and conservation of coastal Louisiana hinges on understanding the patterns and processes underlying habitat heterogeneity on the landscape and therefore the species that inhabits this region, including secretive marshbirds. Elusive in nature, this guild of birds has evolved under dynamic hydroperiods, and myriad plant communities present within wetlands. Only recently, however, has research focused on the role of hydrologic dynamics and vegetative structure and distribution on abundance, movement and detection of marshbirds, specifically within southeastern Louisiana. This study aimed to quantify the ecological patterns and processes, particularly hydrologic processes and landscape structure, driving breeding secretive marshbird movement, abundance and …

Environmental, Social, And Molecular Regulation Of Foraging Behavior In The Formosan Subterranean Termite, Arjun Khadka

LSU Doctoral Dissertations

Foraging is a critical activity in social insects, essential for resource acquisition and colony sustenance. In termites, this behavior is shaped by environmental, social, and genetic factors, yet the underlying regulatory mechanisms remain poorly understood. In this study, we examined how environmental food and moisture availability, and the age of termites affected foraging activities, along with the molecular regulation of foraging in the Formosan subterranean termite, Coptotermes formosanus, using a combination of behavioral assays, transcriptomics, and molecular biology approaches. First, we demonstrate that food and moisture deprivation (FMD) significantly affects foraging, with termites under deprivation conditions exhibiting increased foraging …

Novel Tools And Datamining Techniques To Visualize And Interpret Historical Sugarcane Datasets, Zachary A. Taylor

LSU Master's Theses

Heritable genetic variation is an essential raw ingredient of variety development programs. This variation is acted upon via selection by identifying elite progeny that can be utilized agronomically or exploited as parents. Sugarcane breeders are tasked with creating optimal genetic variation through crossing. Prior knowledge of pedigree and parental performance allows breeders to discern which crosses to prioritize, since the time to make crossing decisions and the space to evaluate tens and thousands of progenies are both limited resources in sugarcane variety development programs. In this project, we have updated and validated the U.S. sugarcane pedigree …

Evaluation Of Diy Pest Management Strategies For The German Cockroach (Blattella Germanica) In The Presence Of Vitamin K Precursors And Synthetic Amorphous Silica, Mohamed S. Shaik

LSU Master's Theses

The German cockroach, Blattella germanica (Linnaeus) is a globally distributed indoor dwelling pest of medical concern. Insecticides are the preferred method of cockroach management due to their low cost, quick action, and availability. However, after continuous use, the development of insecticide resistance has emerged as a challenge for the pest management industry to effectively eliminate German cockroaches. Integrated pest management (IPM) is a sustainable framework which includes the use of glue board traps, vacuuming, in combination with different insecticide formulations such as sprays, gel or dust baits, and insecticide rotation has been successful for the management of German cockroaches. This …

Maternal Hyperleptinemia Alters Placental Transcriptome And Progesterone Regulation Without Affecting Early Equine Fetal Growth, Lucinda L. Thorburn

LSU Master's Theses

While consequences of equine obesity are well defined, the extent to which persistent hyperleptinemia and accompanying leptin (Lep) resistance affect the fetal-maternal environment warrants further exploration. This study compared endocrine, fetal, placental, and uterine parameters during early pregnancy (through day 70) in mares with elevated leptin versus normal leptin (NL) concentrations. Fourteen mares were classified as either NL (n = 6; Lep 0.9 ± 0.3 ng/mL), moderate leptin (ML; n = 4; Lep 3.0 ± 0.3 ng/mL), or high leptin (HL; n = 4; Lep 5.8 ± 0.7 ng/mL) based on annual plasma leptin. Mares were artificially inseminated and induced …

Dose Characterization Of Galactic Cosmic Rays In The Human Brain: A Phits-Based Study With A Segmented Anatomical Phantom, Shanice N. Manning

LSU Master's Theses

Astronauts aboard the International Space Station (ISS) are chronically exposed to a complex space radiation environment composed of galactic cosmic rays (GCR), solar particles, and Earth's trapped radiation. These high-energy particles interact with spacecraft shielding, producing secondary particles that can penetrate inside and deposit energy in sensitive tissues. Although animal studies have been useful in assessing space radiation risks, anatomical and physiological differences limit their applicability to human anatomy especially neuroanatomy. To address this gap, we developed a computational framework to model radiation dose distribution within the human brain using Monte Carlo simulations in Particle and Heavy Ion Transport code …

Anxiety's Impact On Autism Spectrum Disorder Symtomology: An Investigation Into The Relationship Between Two Comorbities, Michaela Brown

LSU Doctoral Dissertations

Autism spectrum disorder (ASD) has been found to be frequently comorbid with many medical and psychological disorders, one of which is anxiety disorders. Research has shown that, when anxiety is present within ASD, various areas of the child’s functioning may be impacted, such as ASD symptom severity, emotional regulation skills, adaptability, social skills and daily living skills. The current study aimed to investigate this relationship of anxiety and ASD. First, within a sample of children and adolescents with ASD, the magnitude of the correlation between specific ASD symptoms parent-reported anxiety was compared to determine if certain ASD symptoms were more …

Role And Electrophysiological Properties Of Sexually Dimorphic Oxytocin Receptor Expressing Neurons In The Anteroventral Periventricular Nucleus Of The Female Mice, Armita Abdollahi Govar

LSU Doctoral Dissertations

Oxytocin is a neurohypophyseal hormone that plays a crucial role in regulating mother-infant bonding and maternal behavior. Oxytocin modulates sex-specific parental behaviors by binding to the oxytocin receptor (OXTR)-expressing neurons in the brain. This study investigates the sexually dimorphic OXTR neurons in the anteroventral periventricular nucleus (AVPV) to understand how oxytocin modulates behavior in females. Specifically, we explored the behavioral roles, neural projections, and intrinsic electrophysiological characteristics of these neurons in the female mice. Using immunohistochemistry revealed that the number of OXTR-expressing neurons was enhanced in postpartum females compared with virgin females, suggesting that these neurons are involved in female-specific …

Soft Hexapod Robot With Tendon-Driven Continuum Legs For Internal Infrastructure Inspection, Setayesh Yavari

LSU Master's Theses

The need for robotic systems capable of operating in confined, hazardous, or complex environments has driven interest in soft and legged platforms for industrial inspection and structural integrity assessment. This thesis presents the design and fabrication of a tentacle-like, soft-legged hexapod robot, which uses six cable-stiffened, pre-curved, tendon-driven continuum robot (TDCR) legs. These biologically inspired legs are designed to offer a balance between compliance and control, enabling the robot to navigate unstructured terrains and potentially grasp cylindrical structures such as pipes. The design phase involved the development and comparison of multiple leg geometries using CAD modeling and finite element analysis …

The Virtual Kitchen Challenge: Psychometric Validation In Cognitively Healthy And Impaired Older Adults, Ross M. Divers

LSU Doctoral Dissertations

Decline in everyday functioning is core diagnostic criteria for mild cognitive impairment (MCI) and dementia. While historically, MCI was considered a stage of generally persevered everyday functioning, it is now widely accepted that subtle though clinically meaningful changes in everyday function can be observed and are predictive of increased risk of future decline and conversion to dementia. Despite this, self and informant report questionnaires of everyday function largely fail to capture this subtle decline in those with MCI, while performance-based measures that may be able to capture this decline are rarely administered clinically due to their laborious administration. Performance-based measures …

Effects Of Staphylococcal Superantigen-Like Protein 11 (Ssl11) On The Host Immune Response During Lung Infection, Sajani Ghaju

LSU Master's Theses

Staphylococcus aureus (S. aureus) is an opportunistic pathogen that produces numerous immune evasion molecules that target various components of the host immune defense to cause infection. One of these is a family of virulence factors, Staphylococcal superantigen-like proteins (SSLs) with 14 members that exhibit host immune-evasion functions. SSL11 has been reported to inhibit neutrophil migration, preventing its recruitment to sites of infection. However, its role in vivo and effect on neutrophil phagocytosis have not been known. This thesis focuses on studying the effect of recombinant SSL11 protein in an in vivo S. aureus-induced pneumonia model and in vitro …

Autism And Down Syndrome: An Examination Of The Baby And Infant Screen For Autism Traits In Toddlers With Down Syndrome, Celeste Tevis

LSU Doctoral Dissertations

Current research suggests that children with Down Syndrome (DS) are at an increased risk for autism spectrum disorder (ASD) compared to the general population. Detecting ASD early in children with DS is crucial to providing access to additional treatment services and supports that may be necessary. Despite a critical need to identify ASD as early as possible, diagnoses of ASD are often delayed in individuals with DS. It can be especially difficult for clinicians to differentiate between symptoms attributed to intellectual developmental disorder (IDD), a primary feature of DS, and possible ASD symptoms. Only two research studies have evaluated the …

Investigation Of Subcellular Damage And Long-Term Non-Cancerous Cardiovascular Effects Following Whole-Body Photon Irradiation, Nousha Afshari

LSU Doctoral Dissertations

Current radiobiological models focus primarily on nuclear DNA damage and fail to fully explain radiation-induced noncancerous health effects. This dissertation investigates whether non-nuclear subcellular structures contribute to radiation-induced biological damage through experimental biomarker analysis and computational microdosimetry. The central hypothesis posits that whole-body photon irradiation results in subcellular non-nuclear damage, specifically increased circulating mitochondrial DNA concentrations, that correlates with radiation dose and long-term noncancerous effects such as cardiovascular disease.

Specific Aim 1 measured mitochondrial and nuclear DNA concentrations in banked blood samples from 72 Chinese rhesus macaques that previously received whole-body photon irradiation ($0-10$ Gy) from Cobalt-60 or LINAC sources. …

Host Plant Resistance To Stink Bugs In Commercial Soybean Varieties, Cristofer Martinez

LSU Master's Theses

Soybean, Glycine max (L.) Merr. (Fabales: Fabaceae), is a major crop in Louisiana, where stink bugs (Hemiptera: Pentatomidae) are economically important pests that reduce seed quality and yield. Among them, the redbanded stink bug, Piezodorus guildinii (Westwood), is considered the most damaging species in the southern U.S. soybean system. Recently, Euschistus quadrator (Rolston), historically a minor pest, has increased in abundance and now dominates the brown stink bug complex in Louisiana soybean fields. While P. guildinii has been widely studied, little is known about E. quadrator.

Given the increasing pest complexity, sustainable management strategies are needed to target …

Increasing The Economic And Social Viability Of Carbon Capture Using Biomass Slurry Fracture Injection, Zachary G. Laird

LSU Master's Theses

The climate is changing. This is a fact not a statement, not a theory, and not a falsehood, this is a fact. At the current projections the world’s average temperature is expected to rise by at least 2°C from pre-industrial averages by 2050 (Emissions Pathways to 2100 - Climate Action Tracker, 2024). This temperature rise will be catastrophic for a vast number of communities. What is driving this changing climate? Humans. In particular the carbon emissions caused by human activities. As humans we consume large amounts of meat, causing the need for cattle to increase, generating large amounts …

Hemp Cultivation Under Off-Season High Tunnel Growth Chamber Environments In South Louisiana, Gabriel Lococo

LSU Master's Theses

Industrial hemp (Cannabis sativa) production in Louisiana began in 2020 with 932 acres cultivated for fiber and cannabidiol (CBD) extraction. By 2024, production had declined to just 58.4 acres (Louisiana Department of Agriculture and Forestry, personal communication). During the 2020–2021 season, over 40% of field-grown hemp was lost due to tropical storms, insect pressure, and diseases associated with warm, wet conditions. To mitigate these challenges, hemp was planted and harvested between November and January, a cooler period with reduced environmental stress.

‘Sour Citron’, a day-neutral cultivar, was selected for its insensitivity to photoperiod, enabling flowering during shorter days. …