Digital Commons Network^™

A Blue Ring Nebula From A Stellar Merger Several Thousand Years Ago, Keri Hoadley, D. Christopher Martin, Brian D. Metzger, Mark Seibert, Andrew Mcwilliam, Ken J. Shen, James D. Neill, Gudmundur Stefansson, Andrew Monson, Bradley E. Schaefer

Faculty Publications

Stellar mergers are a brief but common phase in the evolution of binary star systems1,2. These events have many astrophysical implications; for example, they may lead to the creation of atypical stars (such as magnetic stars3, blue stragglers4 and rapid rotators5), they play an important part in our interpretation of stellar populations6 and they represent formation channels of compact-object mergers7. Although a handful of stellar mergers have been observed directly8,9, the central remnants of these events were shrouded by an opaque shell of dust and molecules10, making it impossible to observe their final state (for example, as a single merged …

The Effects Of In Utero Exposure To Aerosols Generated By Electronic Nicotine Delivery Systems In Neonatal And Adult Offspring, Kerin M. Cahill

LSU Master's Theses

Recently, electronic nicotine delivery systems (ENDS) have become increasingly popular alternatives to cigarette smoking and are perceived as “safe” substitutes. The effects that these devices have on healthy adult lungs are still not fully understood, much less the effects on vulnerable populations such as expectant mothers and neonates. In an effort to better understand the potentially detrimental outcomes that gestational usage may have on both mothers and offspring, we conducted mouse studies on in utero exposures to both, third generation (“box mod”) ENDS aerosols and fourth generation (“pod mod”) JUUL aerosols. In exposures using the box mod device, in utero …

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 …

Typing Tornadoes By Storm Mode In The Southeast United States, Marisa R. Karpinski

LSU Master's Theses

Existing work has noted three major, radar-derived, storm modes associated with tornadoes: supercell, quasi-linear convective systems, and tropical systems. I examine the long-term frequency and seasonality of each storm mode between 1996 and 2017 in the Southeast United States. The Southeast is chosen as a focus for this work due to its well-known and unique combination of tornado vulnerability and exposure. Expanding our knowledge of the radar presentation of tornado-producing thunderstorms in this region could assist in the operational interpretation of these events. In this study, a climatology of F/EF1+ tornadoes (1996 - 2017) is generated for the study area …

Effectiveness Of Mechanical Test In Ascertaining Moisture Damage Of Asphalt Mixtures., Sanchit Sachdeva

LSU Master's Theses

Infiltrated moisture combined with repeated action of traffic and environmental loading generates distresses which adversely affect the durability of asphalt pavements. Almost 94% of states' highway agencies use either the Loaded Wheel Tracking (LWT) test or the Modified Lottman test to capture asphalt mixtures' moisture susceptibility. However, the current LWT and the modified Lottman test practice lack accuracy in relating laboratory performance to observed field performance.

The study's primary objective was to evaluate the capability of different laboratory mechanical test methods to predict moisture susceptibility of asphalt mixtures. Asphalt binder and mixture experiments were conducted to achieve the objective of …

Monitoring Of Remote Hydrocarbon Wells Using Azure Internet Of Things, Derek W. Staal

LSU Master's Theses

Remote monitoring of hydrocarbon wells is a tedious and meticulously thought out task performed to create a cyber-physical bridge between the asset and the owner. There are many systems and techniques on the market that offer this solution but due to their lack of interoperability and/or decentralized architecture they begin to fall apart when remote assets become farther away from the client. This results in extreme latency and thus poor decision making. Microsoft's Azure IoT Edge was the focus of this writing. Coupled with off-the-shelf hardware, Azure's IoT Edge services were integrated with an existing unit simulating a remote hydrocarbon …

Development Of Reduced Order Models Using Reservoir Simulation And Physics Informed Machine Learning Techniques, Mark V. Behl Jr

LSU Master's Theses

Reservoir simulation is the industry standard for prediction and characterization of processes in the subsurface. However, simulation is computationally expensive and time consuming. This study explores reduced order models (ROMs) as an appropriate alternative. ROMs that use neural networks effectively capture nonlinear dependencies, and only require available operational data as inputs. Neural networks are a black box and difficult to interpret, however. Physics informed neural networks (PINNs) provide a potential solution to these shortcomings, but have not yet been applied extensively in petroleum engineering.

A mature black-oil simulation model from Volve public data release was used to generate training data …

Well Testing Of Fracture Corridors In Naturally - Fractured Reservoirs (Nfr), Yingying Guo

LSU Master's Theses

Geological folding and/or faulting may create fractured reservoirs containing a semi-parallel system of long, sparsely - spaced fracture corridors separated by exclusion zones. Presently, the best method for detecting and assessing fracture corridor networks requires drilling, logging, and coring from horizontal wells. However, there is no method to evaluate such reservoirs by pressure testing vertical wells. Vertical wells - completed either in highly-conductive corridors (fracture wells) or in the exclusion zone (matrix wells) would respond quite differently to well testing. Therefore, their pressure response patterns can be used to identify well's placement in the corridor system and some other properties …

Acrl Framework For Impactful Scholarship And Metrics, Rachel Borchardt, Wayne Bivens-Tatum, Polly Boruff-Jones, Robin Chin Roemer, Ted Chodock, Sandra Degroote, Alex R. Hodges, Sigrid Kelsey, Erika Linke, Jennifer Matthews

Faculty Publications

The ACRL Impactful Scholarship and Metrics Task Force was formed primarily to create a framework for the measurement and evaluation of academic librarian scholarship. The framework is designed to address gaps between current scholarly evaluation practices and impactful scholarly activities within academic librarianship, including ways to measure and evaluate the impact of a wide range of research outputs.

Social Support Modifies The Negative Effects Of Acculturation On Obesity And Central Obesity In Mexican Men, Yilin Yoshida, Stephanie Broyles, Richard Scribner, Liwei Chen, Stephen Phillippi, Jeanette Jackson-Thompson, Eduardo J. Simoes, Tung Sung Tseng

Population and Public Health Science Faculty Publications

Background: This study examined the moderating role of social support in the acculturation-obesity/central obesity relationship in Mexican American (MA) men and women. Methods: Data from NHANES 1999–2008 were used. Acculturation derived from language use, country of birth and length of residence in the U.S. Social support assessed emotional and financial support. BMI (≥30) and waist circumference (≥88 cm for women; ≥102 cm for men) measured obesity and central obesity, respectively. Weighted multivariate logistic regression models were used to describe associations. Results: Compared to less acculturation, more acculturation was associated with higher odds of obesity (ORs 2.48; 95% CI 1.06–5.83) and …

Unraveling The Gordian Knot: Eight Testable Hypotheses On The Effects Of Nutrient Enrichment On Tidal Wetland Sustainability, Thomas J. Mozdzer, Elizabeth Burke Watson, William H. Orem, Christopher M. Swarzenski, R. Eugene Turner

Faculty Publications

The position of tidal wetlands at the land-sea interface makes them especially vulnerable to the effects of nutrient discharges and sea level rise (SLR). Experimental studies of coastal wetland nutrient additions report conflicting results among and within habitats, highlighting the importance of site-specific factors, and how spatial and temporal scaling modulates responses. This suite of influences as SIR accelerates creates a "Gordian Knot" that may compromise coastal habitat integrity. We present eight testable hypotheses here to loosen this knot by identifying critical modulators about nutrient form, soil type and porosity, physiochemical gradients, and eco-evolutionary responses that may control the impacts …

Adsorption Structure Of Adenine On Cerium Oxide, Sofiia Bercha, Suman Bhasker-Ranganath, Xiaohui Zheng, Klára Beranová, Mykhailo Vorokhta, Robert G. Acres, Tomáš Skála, Vladimír Matolín, Kevin C. Prince, Ye Xu, Nataliya Tsud

Faculty Publications

The adsorption of adenine on the CeO2(1 1 1)/Cu(1 1 1) surface in vacuum was studied by photoelectron spectroscopy, resonant photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy, and the present work describes in detail the bonding of the molecule to the ordered stoichiometric cerium dioxide film. The experimental findings were supported by density functional theory (DFT + U) analysis of different adsorption geometries of adenine on CeO2(1 1 1). The phase with adenine lying flat on the surface dominates on CeO2(1 1 1) up to 0.1 monolayer (ML) of adenine coverage. The mobility of single molecules was apparently …

Modeling Soil Porewater Salinity In Mangrove Forests (Everglades, Florida, Usa) Impacted By Hydrological Restoration And A Warming Climate, Xiaochen Zhao, Victor H. Rivera-Monroy, Hongqing Wang, Z. George Xue, Cheng Feng Tsai, Clinton S. Willson, Edward Castañeda-Moya, Robert R. Twilley

Faculty Publications

Hydrology is a critical driver controlling mangrove wetlands structural and functional attributes at different spatial and temporal scales. Yet, human activities have negatively affected hydrology, causing mangrove diebacks and coverage loss worldwide. In fact, the assessment of mangrove water budgets, impacted by natural and human disturbances, is limited due to a lack of long-term data and information that hinders our understanding of how changes in hydroperiod and salinity control mangrove productivity and spatial distribution. In this study, we implemented a mass balance-based hydrological model (RHYMAN) that explicitly considers groundwater discharge in the Shark River estuary (SRE, southwestern Everglades) located in …

Deformed Gaussian Operators On Weighted Q-Fock Spaces, Nobuhiro Asai, Hiroaki Yoshida

Journal of Stochastic Analysis

No abstract provided.

Subproduct Systems And Cartesian Systems: New Results On Factorial Languages And Their Relations With Other Areas, Malte Gerhold, Michael Skeide

Journal of Stochastic Analysis

No abstract provided.

Ferric Uptake Regulator (Fur) Reversibly Binds A [2fe-2s] Cluster To Sense Intracellular Iron Homeostasis In Escherichia Coli, Chelsey R. Fontenot, Homyra Tasnim, Kathryn A. Valdes, Codrina V. Popescu, Huangen Ding

Faculty Publications

© 2020 Fontenot et al. The ferric uptake regulator (Fur) is a global transcription factor that regulates intracellular iron homeostasis in bacteria. The current hypothesis states that when the intracellular “free” iron concentration is elevated, Fur binds ferrous iron, and the iron-bound Fur represses the genes encoding for iron uptake systems and stimulates the genes encoding for iron storage proteins. However, the “iron-bound” Fur has never been isolated from any bacteria. Here we report that the Escherichia coli Fur has a bright red color when expressed in E. coli mutant cells containing an elevated intracellular free iron content because of …

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 …

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 …

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 …

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 …

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 …

N,S-Co-Doped Carbon Dots For Rapid Acid Test Paper And Bioimaging, Juan Hou, Jing Qin, Hongyu Pang, Xu Gao, Tiedong Sun, Bin Li

Faculty Publications

Fluorescent N,S-CDs with a quantum yield of 37.8% were synthesized via a one-pot solvothermal method. Detailed characterizations on physical, chemical and optical properties have been investigated. N,S-CDs demonstrated remarkably quenched and enhanced fluorescence in acidic and basic media. Direct qualitative analysis in pH sensor and cell imaging were preliminarily studied. This journal is

Dense Sampling Of Bird Diversity Increases Power Of Comparative Genomics, Shaohong Feng, Josefin Stiller, Yuan Deng, Joel Armstrong, Qi Fang, Andrew Hart Reeve, Duo Xie, Guangji Chen, Chunxue Guo, Brant C. Faircloth, Bent Petersen, Zongji Wang, Qi Zhou, Mark Diekhans, Wanjun Chen, Sergio Andreu-Sánchez, Ashot Margaryan, Jason Travis Howard, Carole Parent, George Pacheco, Mikkel Holger S. Sinding, Lara Puetz, Emily Cavill, Ângela M. Ribeiro, Leopold Eckhart, Jon Fjeldså, Peter A. Hosner, Robb T. Brumfield, Les Christidis, Mads F. Bertelsen, Thomas Sicheritz-Ponten, Dieter Thomas Tietze, Bruce C. Robertson, Gang Song

Faculty Publications

© 2020, The Author(s). Whole-genome sequencing projects are increasingly populating the tree of life and characterizing biodiversity1–4. Sparse taxon sampling has previously been proposed to confound phylogenetic inference5, and captures only a fraction of the genomic diversity. Here we report a substantial step towards the dense representation of avian phylogenetic and molecular diversity, by analysing 363 genomes from 92.4% of bird families—including 267 newly sequenced genomes produced for phase II of the Bird 10,000 Genomes (B10K) Project. We use this comparative genome dataset in combination with a pipeline that leverages a reference-free whole-genome alignment to identify orthologous regions in greater …

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 …