Physical Sciences and Mathematics Commons^™

An Analysis Of Effort, Success, And Attitudes Of Louisiana Hunters By Email And Mixed-Mode Surveys, Michael Sullivan

LSU Master's Theses

ABSTRACT

Louisiana surveys waterfowl hunters every 5 years to assess harvest, harvest practices, demographics, and specific management objectives, as well as to research hypotheses derived from previous surveys of waterfowl hunters. In the 2020 survey, research hypotheses addressed hunter perceptions of changing waterfowl migration patterns, satisfaction, and relationships between perceptions and avidity with survey distribution waves and sample coverage. I surveyed a stratified census of 68,578 Louisiana waterfowl hunters by email following the 2019–2020 season, and asked 31 questions about waterfowl-hunting effort, success, satisfaction, regulatory alternatives, and demographics. I used generalized linear models to test hypotheses about hunters’ perception of …

Computer Simulations Of Diffusional Isotope Effects And Dynamical Properties Of Silicate Melts, Haiyang Luo

LSU Doctoral Dissertations

Silicate melts have served as transport agents in the chemical and thermal evolution of Earth. Diffusional isotope effect in silicate melts is the key to interpret isotope variations in lots of geological samples. Isotopic mass dependence of diffusion is commonly expressed as (Di/Dj)=(mj/mi)^β, where Di and Dj are diffusion coefficients of two isotopes whose masses are mi and mj. However, how the dimensionless empirical parameter β depends on temperature, pressure, and composition remains poorly constrained. Viscosity and electrical conductivity are two fundamental dynamical properties of silicate melts needed to constrain melt distribution in Earth's interior but remain unclear for most …

Modeling Of Island Block Scatter For Intensity Modulated Bolus Electron Conformal Therapy, Joseph G. Scotto

LSU Master's Theses

Purpose: Bolus electron conformal therapy (BECT) benefits treatment of the post-mastectomy chest wall, head and neck, paraspinal muscles, and extremities. Patient dose heterogeneities caused by bolus can be reduced through intensity modulation (IM) across the incident electron beam. This requires passive radiotherapy intensity modulation for electrons (PRIME) devices, which utilize tungsten pins (island blocks) imbedded in machinable foam. IM-BECT treatment planning requires accurate dose calculation using the pencil beam redefinition dose algorithm (PBRA). Currently, the PBRA models island blocks as perfect collimators. This work explores models to account for electrons scattering into and out of the sides of island blocks. …

Effect Of Forage Management Strategies And Land Use Change On Nitrogen Budget And Soil Health Parameters In Pasture Systems, Yili Meng

LSU Doctoral Dissertations

Pastures produce hay for livestock, and they conserve soil, water, and air resources. However, high nitrogen (N) fertilizer demands in pasture production have significant implication on greenhouse gas emission and environmental pollution. Appropriate forage management strategies can reduce environmental N loss and improve soil health, to enhance the long-term pasture productivity. Therefore, this study was carried out to investigate the effects of management strategies on N budgets and soil health parameters in subtropical pastures. Both field and laboratory experiments were conducted to evaluate the effects of N stabilizers including urease inhibitor and nitrification inhibitor on pasture yield, greenhouse gas emission, …

Structural Shielding Considerations For Vmat, Ana Lucia Dieguez

LSU Master's Theses

Introduction: As noted in National Council on Radiation Protection and Measurements (NCRP) Report 151, the medical physicist or other qualified expert has the responsibility to keep abreast of any new technology or treatment method that could potentially impact structural shielding design. Volumetric arc therapy (VMAT) became prevalent after the publication of Report 151 and thus was not explicitly addressed in Report 151. If the shielding-related characteristics of VMAT differ enough from the expectations of Report 151, especially in the circumstance of a vault utilized exclusively for VMAT, a shielding design based on Report 151 could potentially be inadequate. The …

Numerical And Field Study Of Tidal And Subtidal Dynamics In A Bar-Built Estuary: Barataria Bay, Gulf Of Mexico, Ali Reza Payandeh

LSU Doctoral Dissertations

This study investigated tidal and subtidal dynamics of water level, currents, and suspended sediment concentration (SSC) in Barataria Bay, a shallow bar-built estuary of the Northern Gulf of Mexico. First, the local and remote wind forcing contribution on subtidal water level and current variability were examined using three different methods: (i) statistical analysis of observed data, (ii) an analytical model and (iii) a 2-D barotropic numerical model. Results suggested that the remote and local wind effects were equally important at the bay mouth, however local winds were the dominant forcing driver inside the bay. The amplitudes of subtidal fluctuations induced …

An Analysis Of The Presence Of Dialogic Communication Features On Indiana Environmental Organizations' Websites, Jessica Moon

LSU Master's Theses

Dialogic communication is a two-way form of communication that allows entities such as organizations and their publics to share their viewpoints and contribute to decision-making processes openly and equally. The Five Dialogic Principles of Public Relations (ease of use of the interface, usefulness of information, conservation of visitors, generation of return visits, and dialogic loop) is a framework that has been used to examine this form of communication online. Research has shown that organizations’ websites have a generally low presence of features related to the Five Dialogic Principles. The goal of the present study was to determine the …

Electrochemical Reduction Of Hexavalent Chromium In Acetonitrile Using Glassy Carbon Electrodes, Temitope Jegede

LSU Master's Theses

Hexavalent chromium Cr(VI), a form of chromium mainly generated through industrial processes, has attracted great research interests due to its severe toxicity to biological systems. A common way to remove hexavalent chromium from industrial wastes is through reduction to the non-toxic trivalent state. To this end, methods such as chemical reduction, chemical precipitation and coagulation have been used. However, these methods are limited by poor removal efficiency, formation of secondary pollutants (sludge), and are mostly applicable to aqueous solutions. Recently, electrochemical methods have been investigated for reducing hexavalent chromium, but there is a lack of data on the reduction of …

"Super Gzk" Particles In A Classic Kramers' Diffusion-Over-A-Barrier Model. I. The Case Of Protons, S. T. Alnussirat, A. F. Barghouty, G. M. Webb, P. L. Biermann

Faculty Publications

In interactions of ultra-high-energy cosmic ray (UHECR) protons with cosmic microwave background photons, we focus in this work on photopion production reactions and the effects of the measured, broad, energy-loss distributions in these reactions on the evolution of the protons' density functions in energy space. We rely on a Fokker-Planck transport equation in energy space whose transport coefficients are calculated using laboratory measurements. We also derive a Fokker-Planck potential that accounts for both systematic (drift) and stochastic (dispersive) energy losses due to photopion production reactions. Our results show that dispersive energy losses have significant effects on estimating the protons' horizon …

Relating Dust Reference Models To Conventional Systems In Manifestly Gauge Invariant Perturbation Theory, Kristina Giesel, Bao-Fei Li, Parampreet Singh

Faculty Publications

Models with dust reference fields in relational formalism have proved useful in understanding the construction of gauge invariant perturbation theory to arbitrary orders in the canonical framework. These reference fields modify the dynamical equations for perturbation equations. However, important questions remain open on the relation with conventional perturbation theories of inflaton coupled to gravity and of multifluid systems, and on understanding modifications in terms of physical degrees of freedom. These gaps are filled in this manuscript for Brown-Kuchar and Gaussian dust models, both of which involve three scalar physical degrees of freedom. We establish a relationship of these models with …

Octo-Tiger: A New, 3d Hydrodynamic Code For Stellar Mergers That Uses Hpx Parallelization, Dominic C. Marcello, Sagiv Shiber, Orsola De Marco, Juhan Frank, Geoffrey C. Clayton, Patrick M. Motl, Patrick Diehl, Hartmut Kaiser

Faculty Publications

OCTO-TIGER is an astrophysics code to simulate the evolution of self-gravitating and rotating systems of arbitrary geometry based on the fast multipole method, using adaptive mesh refinement. OCTO-TIGER is currently optimized to simulate the merger of well-resolved stars that can be approximated by barotropic structures, such as white dwarfs (WDs) or main-sequence stars. The gravity solver conserves angular momentum to machine precision, thanks to a 'correction' algorithm. This code uses firx parallelization, allowing the overlap of work and communication and leading to excellent scaling properties, allowing for the computation of large problems in reasonable wall-clock times. In this paper, we …

Simulation Of Compound Flood Events In Low-Gradient Coastal Watershed, Felix Luis Santiago-Collazo

LSU Doctoral Dissertations

Low-gradient coastal watersheds are susceptible to flooding caused by various flows such as rainfall, tides, and storm surge. Compound flooding occurs when at least two of these mechanisms happen simultaneously or in close succession. Different inundation models, observed data, and/or a combination of these are coupled through varying techniques involving one-way, loosely, tightly, or fully coupled approaches to assess compound flooding. This study presents a one-dimensional (1-D), fully coupled compound inundation model based on the Shallow Water equations. This model approach simultaneously simulates the free water surface variations in the ocean domain (i.e., tide and storm surge modeling), rainfall-runoff in …

Investigation On The Structure And Dynamics Of Lithium Ion Solvation Shell By Linear And Non-Linear Infrared Spectroscopy, Xiaobing Chen

LSU Doctoral Dissertations

Lithium ion battery (LIB) is a lightweight, rechargeable and powerful battery that is used widely from mobile phones to laptops to electric cars. It has many exceptional advantages such as high energy density, high output power, relatively low self-discharge, etc. However, it has some disadvantages such as safety issues, capacity loss, and expensive manufacture. LIB is composed of three main components: electrolytes, positive and negative electrodes. Researchers have been working on improving the performance of LIB for the past decade, but only a few have focused on investigating the electrolytes at the molecular level. In addition, the molecular mechanisms behind …

Berry-Esseen Bounds For Approximate Maximum Likelihood Estimators In The Α-Brownian Bridge, Khalifa Es-Sebaiy, Jabrane Moustaaid, Idir Ouassou

Journal of Stochastic Analysis

No abstract provided.

Characterizing And Optimizing Asynchronous Event-Driven Architecture For Modern Cloud Systems, Shungeng Zhang

LSU Doctoral Dissertations

Achieving good performance and high efficiency simultaneously is an essential requirement for emerging modern cloud systems such as e-commerce due to their business impact. For example, Akamai reported that every 100ms delay in website load time could lead to a 6% drop in sales. Unfortunately, achieving good performance (e.g., low latency) for modern cloud systems at high resource utilization is significantly challenging. Despite continuing efforts by cloud professionals, however, they have consistently experienced performance degradation problems (e.g., the long-tail latency problem) due to the bursty workload in the cloud. To resolve the performance degradation problems, many previous research efforts have …

Numeric And Dynamic B-Stability, Exact-Monotone And Asymptotic Two-Point Behavior Of Theta Methods For Stochastic Differential Equations, Henri Schurz

Journal of Stochastic Analysis

No abstract provided.

A Generalized, Modular Approach To Treating Moving Tumors With Ion Beams, Michelle Jennifer Lis

LSU Doctoral Dissertations

Despite advancements in cancer therapy, certain indications continue to have a poor prognosis, including cancers of the thorax. Existing methods for treating moving tumors with carbon ions have shown promise, but require technologically complex facilities and still have inherent limitations to mitigating tumor motion. The goal of this dissertation was to develop and test a safe, portable, and modular motion-synchronized dose delivery system (M-DDS) and its peripheral components as a framework for studying motion mitigation with ion beams.

We designed and integrated a motion-synchronized radiotherapy approach, called multi-phase 4D delivery (MP4D), as modular units of a clinical dose delivery system. …

Loop Quantum Black Hole Extensions Within The Improved Dynamics, Rodolfo Gambini, Javier Olmedo, Jorge Pullin

Faculty Publications

We continue our investigation of an improved quantization scheme for spherically symmetric loop quantum gravity. We find that in the region where the black hole singularity appears in the classical theory, the quantum theory contains semi-classical states that approximate general relativity coupled to an effective anisotropic fluid. The singularity is eliminated and the space-time can be continued into a white hole space-time. This is similar to previously considered scenarios based on a loop quantum gravity quantization.

Mapping Plastic Pollution In The Amite Watershed, Louisiana, Gourav Divan

LSU Master's Theses

Microplastics have quickly emerged as a concerning pollutant in both freshwater and marine environments. Their recent discovery means that their impacts are still being studied, however, it is important to continuously monitor their concentrations. An important conduit of plastic pollution to marine environments are rivers and streams. Previous models have estimated the transport of plastics from land to sea in many parts of the world. Most of these models, however, have been conducted at coarse spatial resolutions that make it difficult to establish tractable management programs to minimize this impact. Here, a previously existing model was applied to model for …

An Equivalence Between Contact Gluing Maps In Sutured Floer Homology: A Conjecture Of Zarev, Charles Ryan Leigon

LSU Doctoral Dissertations

We show that the contact gluing map of Honda, Kazez, and Matic has a natural algebraic description in bordered sutured Floer homology. In particular, we establish Zarev's conjecture that his gluing map on sutured Floer homology is equivalent, in the appropriate sense, to the contact gluing map. This further solidifies the relationship between bordered Floer theory and contact geometry.

On Distributions Of Self-Adjoint Extensions Of Symmetric Operators, Franco Fagnola, Zheng Li

Journal of Stochastic Analysis

No abstract provided.

Sphincs_Bssn: A General Relativistic Smooth Particle Hydrodynamics Code For Dynamical Spacetimes, S. Rosswog, P. Diener

Faculty Publications

We present a new methodology for simulating self-gravitating general-relativistic fluids. In our approach the fluid is modelled by means of Lagrangian particles in the framework of a general-relativistic (GR) smoothed particle hydrodynamics (SPH) formulation, while the spacetime is evolved on a mesh according to the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation that is also frequently used in Eulerian GR-hydrodynamics. To the best of our knowledge this is the first Lagrangian fully general relativistic hydrodynamics code (all previous SPH approaches used approximations to GR-gravity). A core ingredient of our particle-mesh approach is the coupling between the gas (represented by particles) and the spacetime (represented …

Noncommutative Tensor Triangular Geometry And Its Applications To Representation Theory, Kent Barton Vashaw

LSU Doctoral Dissertations

One of the cornerstones of the representation theory of Hopf algebras and finite tensor categories is the theory of support varieties. Balmer introduced tensor triangular geometry for symmetric monoidal triangulated categories, which united various support variety theories coming from disparate areas such as homotopy theory, algebraic geometry, and representation theory. In this thesis a noncommutative version will be introduced and developed. We show that this noncommutative analogue of Balmer's theory can be determined in many concrete situations via the theory of abstract support data, and can be used to classify thick tensor ideals. We prove an analogue of prime ideal …

Wildfires: Vegetation Recovery And The Potential For Future Fires, Moses Okonkwo

LSU Master's Theses

Analysis of satellite imagery combined with Geographic Information Systems (GIS), often allows for observing the increasing changes in land cover dynamics. These changes are often on a macro scale buoyed by natural hazards such as wildfires. This study examines the vegetation recovery dynamics by using multispectral data and also gleaned insight in the applications of Hyperspectral satellite imagery in the study of vegetation dynamics. Both Landsat 8 Operational Land Imager (OLI) (multispectral) and the Earth-Observing One (EO-1) (hyperspectral) data are freely available; however the former has a limited spatial and temporal coverage. The relationship between vegetation recovery, elevation, aspect and …

Anticipating Linear Stochastic Differential Equations With Adapted Coefficients, Hui-Hsiung Kuo, Pujan Shrestha, Sudip Sinha

Journal of Stochastic Analysis

No abstract provided.

On Properties Of Weil Sums Of Binomials, Liem P. Nguyen

LSU Doctoral Dissertations

This dissertation explores questions regarding the Weil sum of binomials, a finite field character sum originated from information theory. The Weil spectrum counts distinct values of the Weil sum through invertible elements in the finite field. The value of these sums and the size of the Weil spectrum are of particular interest, as they link problems in information theory, coding theory, and cryptography to other areas of math such as number theory and arithmetic geometry. In the setting of Niho exponents, we prove the Vanishing Conjecture of Helleseth ($1971$) on the presence of zero values in the Weil spectrum and …

Ecosytem Services: Delivering Decision-Making For Salt Marshes, Philine S. E. Zu Ermgassen, Ronald Baker, Michael W. Beck, Kate Dodds, Sophus O. S. E. Zu Ermgassen, Debbrota Mallick, Matthew D. Taylor, R. Eugene Turner

Faculty Publications

No abstract provided.

Applications Of Nonstandard Analysis In Probability And Measure Theory, Irfan Alam

LSU Doctoral Dissertations

This dissertation broadly deals with two areas of probability theory and investigates how methods from nonstandard analysis may provide new perspectives in these topics. In particular, we use nonstandard analysis to prove new results in the topics of limiting spherical integrals and of exchangeability.

In the former area, our methods allow us to represent finite dimensional Gaussian measures in terms of marginals of measures on hyperfinite-dimensional spheres in a certain strong sense, thus generalizing some previously known results on Gaussian Radon transforms as limits of spherical integrals. This first area has roots in the kinetic theory of gases, which is …

Validation Of A Respiratory Gating System For Automated Delivery Of The Deep Inspiration Breath-Hold Technique, Michael G. Stock

LSU Master's Theses

Purpose: To validate the performance of a respiratory gating system for the automated delivery of the deep inspiration breath-hold (DIBH) technique.

Methods: The gating system utilized an automatic gating interface (Elekta Response) which connected a marker-based respiratory motion monitoring system to the linear accelerator control system. The gating system was characterized dosimetrically and temporally using two distinct approaches. Central-axis output and energy constancy were evaluated across 8 beam-matched linear accelerators. Additionally, a representative set of 5 treatment plans were delivered both non-gated and gated to a 2D diode array (MapCHECK). The respiratory motion monitoring system optically tracked a reflective marker …

Characterizing The Northern Hemisphere Circumpolar Vortex Through Space And Time, Nazla Bushra

LSU Doctoral Dissertations

This hemispheric-scale, steering atmospheric circulation represented by the circumpolar vortices (CPVs) are the middle- and upper-tropospheric wind belts circumnavigating the poles. Variability in the CPV area, shape, and position are important topics in geoenvironmental sciences because of the many links to environmental features. However, a means of characterizing the CPV has remained elusive. The goal of this research is to (i) identify the Northern Hemisphere CPV (NHCPV) and its morphometric characteristics, (ii) understand the daily characteristics of NHCPV area and circularity over time, (iii) identify and analyze spatiotemporal variability in the NHCPV’s centroid, and (iv) analyze how CPV features relate …