Physical Sciences and Mathematics Commons^™

Trophic Relationships Between Tadpoles And Other Aquatic Organisms In Sub-Tropical Ponds, Kira Cates

Honors Capstones

No abstract provided.

The Effect Of Channel Stability On Fish Condition And Diet In Thompson Creek, La, Alexia Lagrone

Honors Capstones

No abstract provided.

Opers On The Projective Line, Wronskian Relations, And The Bethe Ansatz, Ty J. Brinson

Honors Capstones

No abstract provided.

Are Long-Period Exoplants Around Cool Stars More Common Than We Thought?, Emily Jane Safron

LSU Doctoral Dissertations

The Kepler mission has been the catalyst for discovery of nearly 5,000 confirmed and candidate exoplanets. The majority of these candidates orbit Sun-like stars, and have orbital periods comparable to or shorter than that of the Earth, due to the selection bias inherent in the transit method and the limitations of automated transit search algorithms. We aim to develop a richer understanding of the population of exoplanets around the lowest-mass stars, the M spectral type. We are particularly interested in exoplanets with long orbital periods, which are difficult or impossible to find using standard transit search algorithms. In our study, …

Performance Analysis And Improvement For Scalable And Distributed Applications Based On Asynchronous Many-Task Systems, Nanmiao Wu

LSU Doctoral Dissertations

As the complexity of recent and future large-scale data and exascale systems architectures grows, so do productivity, portability, software scalability, and efficient utilization of system resources challenges presented to both industry and the research community. Software solutions and applications are expected to scale in performance on such complex systems. Asynchronous many-task (AMT) systems, taking advantage of multi-core architectures with light-weight threads, asynchronous executions, and smart scheduling, are showing promise in addressing these challenges.

In this research, we implement several scalable and distributed applications based on HPX, an exemplar AMT runtime system. First, a distributed HPX implementation for a parameterized benchmark …

Synthesis Of Thiol-Acrylate Hydrogels For 3d Cell Culture And Microfluidic Applications, Anowar Hossain Khan

LSU Doctoral Dissertations

Globally cell culture is an $18.98 billion industry as of 2020, with an 11.6 percent annual growth rate. Drug discovery has an estimated worth of $69.8 billion in 2020 and is predicted to grow to $110.4 billion by 2025. Three-dimensional (3D) cell culture of cancer cells is one of the rapidly growing felids since it better recapitulates in vivo conditions compared to two-dimensional (2D) models. However, it is challenging to grow 3D tumor spheroids outside the body, and some of the existing technology can generate these spheroids outside the human body but poorly mimic in vivo tumor models. Therefore, there …

The Spectra Of Hydrogen-Deficient Carbon Stars: The Effects Of Evolution And Nucleosynthesis, Courtney Lauren Crawford

LSU Doctoral Dissertations

The rare class of stars known as the Hydrogen-deficient Carbon (HdC) stars includes the R Coronae Borealis (RCB) variables and the non-variable Dustless HdC (dLHdC) stars. These stars are believed to be formed via the merger of two white dwarf (WD) stars. They are known to exhibit many spectral peculiarities, such as partial helium burning products, enhancement of s-processed material and severe hydrogen-deficiency. In this work I explore many facets of HdC evolution. I begin by creating 18 HdC models in the stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA) by merging two WD progenitors and evolving the …

Computational Study Of The Reactions Of Heteroatomic Compounds On Ceo2, Suman Bhasker Ranganath

LSU Doctoral Dissertations

The mechanisms of ambient-temperature reactions of heteroatomic compounds catalyzed by ceria (CeO₂), an archetypical reducible oxide, for enzyme mimetics, environmental protection, and chemical synthesis are investigated in this dissertation using theoretical methods. CeO₂ is modeled with thermodynamically stable low-index surfaces exposed by commonly studied ceria thin films and nano particles. To understand phosphatase-like dephosphorylation activity, stable adsorption states and surface reactions of model phosphates are examined. Binding of the central P-atom to surface lattice oxygen (O_latt) supplemented by phosphoryl O-Ce interaction is the only stable adsorption state for the un-dissociated molecule. Deprotonation of phosphate monoesters, …

Kinetics, Characterization, And Applications In The Development Of Next-Generation Cure-On-Demand Polymeric Materials Through Frontal Polymerization, Daniel Paul Gary

LSU Doctoral Dissertations

Frontal polymerization (FP) is a process in which a front propagates in a localized reaction zone converting monomer into polymer. This work explored the kinetics and applications of FP for the development of cure-on-demand materials.

The kinetic effects of fillers on frontal polymerization have not been thoroughly explored. In Chapter 2, various fillers were used, and their effects on front velocity and front temperature were determined. Clay minerals are primarily used, but the thermal conductive effects of milled carbon fiber were also explored. It was found that some fillers inhibit frontal polymerization through radical scavenging, while others increased the front …

Spectral Theorem Approach To The Characteristic Function Of Quantum Observables, Andreas Boukas

Journal of Stochastic Analysis

No abstract provided.

Digital Discrimination In The Sharing Economy: Evidence, Policy, And Feature Analysis, Miroslav Tushev

LSU Doctoral Dissertations

Applications (apps) of the Digital Sharing Economy (DSE), such as Uber, Airbnb, and TaskRabbit, have become a main facilitator of economic growth and shared prosperity in modern-day societies. However, recent research has revealed that the participation of minority groups in DSE activities is often hindered by different forms of bias and discrimination. Evidence of such behavior has been documented across almost all domains of DSE, including ridesharing, lodging, and freelancing. However, little is known about the under- lying design decisions of DSE systems which allow certain demographics of the market to gain unfair advantage over others. To bridge this knowledge …

Construction Of The Canonical Representation From A Noncanonical Representation, Yuji Hibino

Journal of Stochastic Analysis

No abstract provided.

Peak Chlorophyll A Concentrations In The Lower Mississippi River From 1997 To 2018, R. Eugene Turner, Charles S. Milan, Erick M. Swenson, James M. Lee

Faculty Publications

Large and turbid rivers have varying temperatures, light conditions, nutrient availability, and nutrient ratios that may affect phytoplankton communities and occur within a changing world of point and nonpoint source nutrient loadings. We investigated how these physical and chemical factors affect Chlorophyll a (Chl a) concentrations in the Mississippi River, the largest river in North America, by sampling 878 times from February 1997 to December 2018 near its terminus at Baton Rouge, Louisiana. We hypothesized that nutrient concentrations and ratios were significant factors limiting phytoplankton biomass accumulations in this turbid river. The Chl a concentrations were in the "poor" water …

90snet:, Seth Richard

Honors Capstones

No abstract provided.

Gaia Gral: Gaia Dr2 Gravitational Lens Systems. Vii. Xmm-Newton Observations Of Lensed Quasars, Thomas Connor, Daniel Stern, Alberto Krone-Martins, S. G. Djorgovski, Matthew J. Graham

Faculty Publications

We present XMM-Newton X-ray observations of nine confirmed lensed quasars at 1 less than or similar to z less than or similar to 3 identified by the Gaia Gravitational Lens program. Eight systems are strongly detected, with 0.3-8.0 keV fluxes F (0.3-8.0) greater than or similar to 5 x10(-14) erg cm(-2) s(-1). Modeling the X-ray spectra with an absorbed power law, we derive power-law photon indices and 2-10 keV luminosities for the eight detected quasars. In addition to presenting sample properties for larger quasar population studies and for use in planning for future caustic-crossing events, we also identify three quasars …

A Multiparameter Degeneracy In Microlensing Events With Extreme Finite Source Effects, Samson A. Johnson, Matthew T. Penny, B. Scott Gaudi

Faculty Publications

For microlenses with sufficiently low mass, the angular radius of the source star can be much larger than the angular Einstein ring radius of the lens. For such extreme finite source effect (EFSE) events, finite source effects dominate throughout the duration of the event. Here, we demonstrate and explore a continuous degeneracy between multiple parameters of such EFSE events. The first component in the degeneracy arises from the fact that the directly observable peak change of the flux depends on both the ratio of the angular source radius to the angular Einstein ring radius and the fraction of the baseline …

New Limit Theorems For Increments Of Birth-And-Death Processes With Linear Rates, Alexander Ya. Kreinin, Vladimir V. Vinogradov

Journal of Stochastic Analysis

No abstract provided.

Backward Stochastic Differential Equations With No Driving Martingale And Pseudo-Pdes, Adrien Barrasso, Francesco Russo

Journal of Stochastic Analysis

No abstract provided.

Infrared Investigation Of Lithium Ion Electrolytes: Characterization Of Structure And Dynamics Via Linear And Nonlinear Spectroscopy, Jeramie Christopher Rushing

LSU Doctoral Dissertations

Lithium ion batteries are widely employed in energy storage, but the connection between the molecular interactions in their electrolytes and the macroscopic properties remains elusive. Across three vastly different electrolytes, speciation and dynamics were studied via linear and nonlinear infrared spectroscopy to shed light on this relationship. The impact of mixed solvation on ionic speciation was studied from the perspective of the anion, which revealed a significant energetic favorability for the formation of contact ion pairs in linear carbonate solvents over cyclic carbonates. Infrared spectroscopy and density functional theory calculations described a complete inversion of the speciation due to solvent …

Connecting The Dots: Transmission Of Stony Coral Tissue Loss Disease From The Marquesas To The Dry Tortugas, Thomas Dobbelaere, Daniel M. Holstein, Erinn M. Muller, Lewis J. Gramer, Lucas Mceachron, Sara D. Williams, Emmanuel Hanert

Faculty Publications

For the last 7 years, Florida's Coral Reef (FCR) has suffered from widespread and severe coral loss caused by stony coral tissue loss disease (SCTLD). First observed off the coast of Miami-Dade county in 2014, the outbreak has since spread throughout the entirety of FCR and some areas of the Caribbean. However, the propagation of the disease through FCR seemed to slow down when it reached the western end of the Marquesas in August 2020. Despite being present about 30 km (similar to 20 miles) from the Dry Tortugas (DRTO), SCTLD was not reported in this area before May 2021. …

Search Full Text Options Here 2 Of 4 Kmt-2021-Blg-0912lb: A Microlensing Super Earth Around A K-Type Star, Cheongho Han, Ian A. Bond, Jennifer C. Yee, Weicheng Zang, Michael D. Albrow

Faculty Publications

Aims. The light curve of the microlensing event KMT-2021-BLG-0912 exhibits a very short anomaly relative to a single-lens single-source form. We investigate the light curve for the purpose of identifying the origin of the anomaly.

Methods. We model the light curve under various interpretations. From this, we find four solutions, in which three solutions are found under the assumption that the lens is composed of two masses (2L1S models), and the other solution is found under the assumption that the source is comprised of binary stars (1L2S model). The 1L2S model is ruled out based on the contradiction that the …

A Bayesian Phase I/Ii Biomarker-Based Design For Identifying Subgroup-Specific Optimal Dose For Immunotherapy, Beibei Guo, Yong Zang

Faculty Publications

Immunotherapy is an innovative treatment that enlists the patient's immune system to battle tumors. The optimal dose for treating patients with an immunotherapeutic agent may differ according to their biomarker status. In this article, we propose a biomarker-based phase I/II dose-finding design for identifying subgroup-specific optimal dose for immunotherapy (BSOI) that jointly models the immune response, toxicity, and efficacy outcomes. We propose parsimonious yet flexible models to borrow information across different types of outcomes and subgroups. We quantify the desirability of the dose using a utility function and adopt a two-stage dose-finding algorithm to find the optimal dose for each …

Singing Strategies Are Linked To Perch Use On Foraging Territories In Heart-Nosed Bats, Grace C. Smarsh, Ashley M. Long, Michael Smotherman

Faculty Publications

Acoustic communication allows animals to coordinate and optimize resource utilization in space. Cardioderma cor, the heart-nosed bat, is one of the few species of bats known to sing during nighttime foraging. Previous research found that heart-nosed bats react aggressively to song playback, supporting the territorial defense hypothesis of singing in this species. We further investigated the territorial defense hypothesis from an ecological standpoint, which predicts that singing should be associated with exclusive areas containing a resource, by tracking 14 individuals nightly during the dry seasons in Tanzania. We quantified the singing behavior of individuals at all perches used throughout the …

Strict Lyapunov Functions And Feedback Controls For Sir Models With Quarantine And Vaccination, Hiroshi Ito, Michael Malisoff, Frederic Mazenc

Faculty Publications

We provide a new global strict Lyapunov function construction for a susceptible, infected, and recovered (or SIR) disease dynamics that includes quarantine of infected individuals and mass vaccination. We use the Lyapunov function to design feedback controls to asymptotically stabilize a desired endemic equilibrium, and to prove input-to-state stability for the dynamics with a suitable restriction on the disturbances. Our simulations illustrate the potential of our feedback controls to reduce peak levels of infected individuals.

Docking And Molecular Dynamic Of Microalgae Compounds As Potential Inhibitors Of Beta-Lactamase, Roberto Pestana-Nobles, Yani Aranguren-Diaz, Elwi Machado-Sierra, Juvenal Yosa, Nataly J. Galan-Freyle,, Laura X. Sepulveda-Montano, Daniel G. Kuroda, Leonardo C. Pacheco-Londono

Faculty Publications

Bacterial resistance is responsible for a wide variety of health problems, both in children and adults. The persistence of symptoms and infections are mainly treated with beta-lactam antibiotics. The increasing resistance to those antibiotics by bacterial pathogens generated the emergence of extended-spectrum beta-lactamases (ESBLs), an actual public health problem. This is due to rapid mutations of bacteria when exposed to antibiotics. In this case, beta-lactamases are enzymes used by bacteria to hydrolyze the beta-lactam rings present in the antibiotics. Therefore, it was necessary to explore novel molecules as potential beta-lactamases inhibitors to find antibacterial compounds against infection caused by ESBLs. …

Whole-Genome Sequencing And Rna-Seq Reveal Differences In Genetic Mechanism For Flowering Response Between Weedy Rice And Cultivated Rice, Richard S. Garcia, Sapphire Coronejo, Jonathan Concepcion, Prasanta K. Subudhi

Faculty Publications

Flowering is a key agronomic trait that influences adaptation and productivity. Previous studies have indicated the genetic complexity associated with the flowering response in a photoinsensitive weedy rice accession PSRR-1 despite the presence of a photosensitive allele of a key flowering gene Hd1. In this study, we used whole-genome and RNA sequencing data from both cultivated and weedy rice to add further insights. The de novo assembly of unaligned sequences predicted 225 genes, in which 45 were specific to PSRR-1, including two genes associated with flowering. Comparison of the variants in PSRR-1 with the 3K rice genome (RG) dataset identified …

Search Full Text Options Here 3 Of 3 Heat-Mitigated Design And Lorentz Force-Based Steering Of An Mri-Driven Microcatheter Toward Minimally Invasive Surgery, Martin Francis Phelan Iii, Mehmet Efe Tiryaki, Jelena Lazovic, Hunter Gilbert, Metin Sitti

Faculty Publications

Catheters integrated with microcoils for electromagnetic steering under the high, uniform magnetic field within magnetic resonance (MR) scanners (3-7 Tesla) have enabled an alternative approach for active catheter operations. Achieving larger ranges of tip motion for Lorentz force-based steering have previously been dependent on using high power coupled with active cooling, bulkier catheter designs, or introducing additional microcoil sets along the catheter. This work proposes an alternative approach using a heat-mitigated design and actuation strategy for a magnetic resonance imaging (MRI)-driven microcatheter. A quad-configuration microcoil (QCM) design is introduced, allowing miniaturization of existing MRI-driven, Lorentz force-based catheters down to 1-mm …

A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen

Faculty Publications

Blind modulation classification (MC) is an integral part of designing an adaptive or intelligent transceiver for future wireless communications. Blind MC has several applications in the adaptive and automated systems of sixth generation (6G) communications to improve spectral efficiency and power efficiency, and reduce latency. It will become a integral part of intelligent software-defined radios (SDR) for future communication. In this paper, we provide various MC techniques for orthogonal frequency division multiplexing (OFDM) signals in a systematic way. We focus on the most widely used statistical and machine learning (ML) models and emphasize their advantages and limitations. The statistical-based blind …

A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen

Faculty Publications

Blind modulation classification (MC) is an integral part of designing an adaptive or intelligent transceiver for future wireless communications. Blind MC has several applications in the adaptive and automated systems of sixth generation (6G) communications to improve spectral efficiency and power efficiency, and reduce latency. It will become a integral part of intelligent software-defined radios (SDR) for future communication. In this paper, we provide various MC techniques for orthogonal frequency division multiplexing (OFDM) signals in a systematic way. We focus on the most widely used statistical and machine learning (ML) models and emphasize their advantages and limitations. The statistical-based blind …

A New Matroid Lift Construction And An Application To Group-Labeled Graphs, Zach Walsh

Faculty Publications

A well-known result of Brylawski constructs an elementary lift of a matroid M from a linear class of circuits of M. We generalize this result by constructing a rank-k lift of M from a rank-k matroid on the set of circuits of M. We conjecture that every lift of M arises via this construction. We then apply this result to group-labeled graphs, generalizing a construction of Zaslavsky. Given a graph G with edges labeled by a group, Zaslavsky's lift matroid K is an elementary lift of the graphic matroid M(G) that respects the group-labeling; specifically, the cycles of G that …