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Accelerated Broadband Spectra And Attosecond Charge Migration Simulations Using Real-Time Time-Dependent Density Functional Theory, Adam S. Bruner

LSU Doctoral Dissertations

In this dissertation, the calculations of light-matter interactions offer insight into the structure and dynamical response of electrons in molecular systems. Such information is useful for characterizing molecules, electronic structure, photochemistry, photomaterials, and a host of other applications. In the first part of this work, simulations of broadband absorption spectra are accelerated by the use of Pad´e approximanants of Fourier Transforms and dipole decomposition. Electronic absorption spectra from valence and core levels are obtained using time-dependent methods and compared to results from established perturbative techniques. In addition, core level absorption spectra are calculated for a nickel porphyrin and shown to …

Experimental, Analytical, And Numerical Evaluation Of The Mechanical Properties Of The Brain Tissue, Aref Samadidooki

LSU Doctoral Dissertations

A true understanding of the mechanisms behind most of the brain diseases is still out of reach. For several years, the interest of scientists has been focused on the genetic and biological causes, however, recent studies unraveled the importance of the biomechanics of the brain growth, folding, impact resistance, and deformation on its pathological conditions. While, a wide range of different methods have been used for characterization of the mechanical properties of the brain at the tissue level, the obtained results from different studies are extremely scattered and sometimes in contrast to one another. Since the brain tissue is extremely …

Development Of A Slab-Based Monte Carlo Proton Dose Algorithm With A Robust Material-Dependent Nuclear Halo Model, John Wesley Chapman Jr

LSU Doctoral Dissertations

Pencil beam algorithms (PBAs) are often utilized for dose calculation in proton therapy treatment planning because they are fast and accurate under most conditions. However, as discussed in Chapman et al (2017), the accuracy of a PBA can be limited under certain conditions because of two major assumptions: (1) the central-axis semi-infinite slab approximation; and, (2) the lack of material dependence in the nuclear halo model. To address these limitations, we transported individual protons using a class II condensed history Monte Carlo and added a novel energy loss method that scaled the nuclear halo equation in water to arbitrary geometry. …

Work And Reversibility In Quantum Thermodynamics, Álvaro M. Alhambra, Stephanie Wehner, Mark M. Wilde, Mischa P. Woods

Faculty Publications

It is a central question in quantum thermodynamics to determine how irreversible is a process that transforms an initial state ρ to a final state σ and whether such irreversibility can be thought of as a useful resource. For example, we might ask how much work can be obtained by thermalizing ρ to a thermal state σ at temperature T of an ambient heat bath. Here, we show that, for different sets of resource-theoretic thermodynamic operations, the amount of entropy produced along a transition is characterized by how reversible the process is. More specifically, this entropy production depends on how …

Visualization And Quantification Of Cancer-Associated Enzymes With Fluorescent Small-Molecule Substrate Probes, Zhenhua Shen

LSU Doctoral Dissertations

Fluorescence imaging can be used both as a tool to diagnose diseases and guide treatment in clinical settings, and as a technique to monitor dynamic events or biological species in basic research. Therefore, there is a great need for the development of a multitude of fluorescent probes that can be incorporated with fluorescence imaging techniques to track and report endogenous enzymes with high specificity and selectivity. In contrast to always-on and targeted always-on fluorescent probes that continually emit light, activity-based substrate probes either emit low numbers of photons or are completely quenched. They can be converted to highly fluorescent reporters …

Spatial Trends And Variability Of Marsh Accretion Rates In Barataria Basin, Louisiana, Usa Using 210pb And 137cs Radiochemistry, Samuel Bryant Shrull

LSU Master's Theses

Coastal Louisiana is presently experiencing large amounts of coastal land loss with estimated rates exceeding 50 km² lost per year. In an attempt to mitigate or reverse land loss, billions of dollars are earmarked for restoration projects that promote land reclamation, habitat stabilization, and defending against saline intrusion. This study was performed in an effort to better understand spatial trends of accretion rates in Barataria Basin in coastal Louisiana. Data for this project came from twenty-five shallow cores extracted over a broad span of the entire basin, from freshwater to saline environments. Cores were processed for ¹³⁷Cs and …

Templates For Representable Matroids, Kevin Manuel Grace

LSU Doctoral Dissertations

The matroid structure theory of Geelen, Gerards, and Whittle has led to a hypothesis that a highly connected member of a minor-closed class of matroids representable over a finite field is a mild modification (known as a perturbation) of a frame matroid, the dual of a frame matroid, or a matroid representable over a proper subfield. They introduced the notion of a template to describe these perturbations in more detail. In this dissertation, we determine these templates for various classes and use them to prove results about representability, extremal functions, and excluded minors.

Chapter 1 gives a brief introduction …

Investigation Of Structure And Dynamics Of Deep Eutectic Solvent Using Infrared Spectroscopy, Yaowen Cui

LSU Doctoral Dissertations

Deep Eutectic Solvents (DES) are liquid mixtures prepared from solids. As a new class of green solvents, DES not only share many properties with ionic liquids, such as low volatility, conductivity, tailorable constituents, but also have some advantages over ionic liquids, like easier preparation, safe and inexpensive materials, biodegradability, low toxicity, and excellent solubility. Because of those attractive properties, DES has been studied in many scientific and engineering fields. However, compared with the great number of studies of the application, many questions about structure and dynamics of DES are unanswered. To shed light on the mystery of solvent or solvation …

Two Results In Drawing Graphs On Surfaces, Joshua E. Fallon

LSU Doctoral Dissertations

In this work we present results on crossing-critical graphs drawn on non-planar surfaces and results on edge-hamiltonicity of graphs on the Klein bottle. We first give an infinite family of graphs that are 2-crossing-critical on the projective plane. Using this result, we construct 2-crossing-critical graphs for each non-orientable surface. Next, we use 2-amalgamations to construct 2-crossing-critical graphs for each orientable surface other than the sphere. Finally, we contribute to the pursuit of characterizing 4-connected graphs that embed on the Klein bottle and fail to be edge-hamiltonian. We show that known 4-connected counterexamples to edge-hamiltonicity on the Klein bottle are hamiltonian …

Essays On The Impact Of Parents' Investment And School Curriculum On Educational Outcomes In China, Han Yu

LSU Doctoral Dissertations

This dissertation consists of two essays studying how students’ educational outcomes are affected by parents’ investment and school curriculum, which are two of the most important determinants of students’ educational performance, respectively. Specifically, in chapter 2, I investigate whether Chinese children born in the auspicious years of Dragon perform better than their comparable peers in school. Using three recently collected datasets from China, I find that students born in the years of the Dragon indeed outperformed their peers in study. I furtherly test the possible mechanisms for the better performance of the “Dragons” in school. The results suggest that parents’ …

Children With Adha Or Anxiety Disorders: Are Common Or Specific Variables Associated With Decreased Performance On Intelligence Indices?, Franziska Noacklesage

LSU Doctoral Dissertations

Although overall psychopathology has been linked to lower intellectual functioning, research has yet to investigate whether one or multiple specific underlying symptom clusters significantly correlate with working memory (WM) and processing speed (PS) deficits. The current study investigated these relationships as they apply to Attention-Deficit/Hyperactivity Disorder (ADHD) and anxiety disorders. As such, one goal of this study was to investigate the extent to which common and specific symptom clusters would predict ADHD and anxiety diagnoses compared to a control group when PS and WM were partialled out. A further goal was to determine if one could differentially predict ADHD from …

Energy-Constrained Two-Way Assisted Private And Quantum Capacities Of Quantum Channels, Noah Davis, Maksim E. Shirokov, Mark M. Wilde

Faculty Publications

With the rapid growth of quantum technologies, knowing the fundamental characteristics of quantum systems and protocols is essential for their effective implementation. A particular communication setting that has received increased focus is related to quantum key distribution and distributed quantum computation. In this setting, a quantum channel connects a sender to a receiver, and their goal is to distill either a secret key or entanglement, along with the help of arbitrary local operations and classical communication (LOCC). In this work, we establish a general theory of energy-constrained, LOCC-assisted private and quantum capacities of quantum channels, which are the maximum rates …

Neighbor And Height Effects On Crown Properties Associated With The Uniform-Stress Principle Of Stem Formation, Thomas J. Dean

Faculty Publications

According to the uniform-stress principle of stem formation, the amount of leaf area a tree carries and the leverage it exerts on the stem determine the stem dimensions. Within an even-aged monoculture, the leaf area per tree and the leverage placed on the stem are functions of tree density and tree height. The uniform-stress principle presents the means to translate density effects on crown characteristics into stem dimensions and total standing volume. This approach is truly a top-down method of simulating growth tree and stand growth because leaf area and other crown properties must be determined before stem size and …

Glyphosate In Soils: Retention, Transport, And Effect Of Phosphate, Joshua Padilla

LSU Master's Theses

Glyphosate [N-(phosphonomethyl) glycine)] (GPS) is currently the most commonly used herbicide worldwide, and is generally considered as immobile in soils. However, numerous reports of the environmental occurrence of the herbicide coupled with recent evidence of human toxicity require further investigation as to the behavior of GPS in the soil environment. The objectives of this study were to quantify GPS sorption and mobility in two Louisiana agricultural soils with varying physiochemical properties; Commerce silt loam and Sharkey clay. Results of batch sorption studies indicated a high affinity of both soils for solvated GPS, with 24-hour Freundlich partitioning coefficients of 158 and …

Joint Geodetic And Seismic Analysis Of Englacial And Subglacial Hydraulic Effects On Surface Crevassing Near A Seasonal, Glacier-Dammed Lake On Gornergletscher, Switzerland, Louis Stephen Garcia

LSU Master's Theses

Glacial outburst floods are difficult to predict and threaten human life. These events are characterized by rapid draining of glacier-dammed lakes via the sub/englacial hydraulic network to the proglacial stream. The glacier-dammed lake on Gornergletscher in Switzerland, which fills and drains each summer, provides an opportunity to study this hazard. For three drainages (2004, 2006, and 2007), icequakes (IQ) are tracked as well as on-ice GPS movement. The seasonal seismic networks had 8 – 24 three-component stations and apertures of about 300 – 400 m on the glacier surface. The seasonal GPS arrays contained 4 – 8 GPS antennae on …

A Comparison Of Causal Inference Methods And Their Application In Big Data Analytics, Xuan Wang

LSU Doctoral Dissertations

With the rise of Big Data analytics, the new field of causal inference (Pearl, 2009) has received more attention in business research fields such as Accounting (Lawrence, Minutti-Meza, & Zhang, 2011) and Marketing (Manganaris, Bhasin, Reid, & Hermiz Keith, 2010). Traditional statistics focuses on correlation which may lead to misleading conclusions because the estimates can be severely biased even when data sets are large. The objective of causal inference is to obtain estimates from observational data that are unbiased and can thus be interpreted as causal. This study provides a systematic comparison of the performance of four causal inference methods …

Strong And Uniform Convergence In The Teleportation Simulation Of Bosonic Gaussian Channels, Mark M. Wilde

Faculty Publications

In the literature on the continuous-variable bosonic teleportation protocol due to Braunstein and Kimble [Phys. Rev. Lett. 80, 869 (1998)PRLTAO0031-900710.1103/PhysRevLett.80.869], it is often loosely stated that this protocol converges to a perfect teleportation of an input state in the limit of ideal squeezing and ideal detection, but the exact form of this convergence is typically not clarified. In this paper, I explicitly clarify that the convergence is in the strong sense, and not the uniform sense, and furthermore that the convergence occurs for any input state to the protocol, including the infinite-energy Basel states defined and discussed here. I also …

Shifting Niche Space In Coastal Landscapes: Spatio-Temporal Patterns Driving Submerged Aquatic Vegetation Across The Northern Gulf Of Mexico, Kristin Elise Demarco

LSU Doctoral Dissertations

Identifying distributions of submerged aquatic vegetation (SAV) across the northern Gulf of Mexico (NGOM) coastal landscape necessitates describing ecological processes in estuarine gradients. SAV assemblages are ecological indicators of aquatic ecosystem health; spatial and temporal distributions are strongly correlated to environmental conditions. Many wildlife species, including waterfowl, are dependent on SAV and seeds in NGOM coastal marshes for food and habitat. To understand SAV distributions at multiple spatial and temporal scales a multi-tiered project was designed to collect SAV presence, species assemblage, and cover data, and cores to describe seed food. The first tier sampled inter-annually in the growing seasons …

The Montevideo Interpretation Of Quantum Mechanics: A Short Review, Rodolfo Gambini, Jorge Pullin

Faculty Publications

The Montevideo interpretation of quantum mechanics, which consists of supplementing environmental decoherence with fundamental limitations in measurement stemming from gravity, has been described in several publications. However, some of them appeared before the full picture provided by the interpretation was developed. As such, it can be difficult to get a good understanding via the published literature. Here, we summarize it in a self-contained brief presentation including all its principal elements.

Physics Potentials With The Second Hyper-Kamiokande Detector In Korea, K. Abe, Ke Abe, S. H. Ahn, H. Aihara, A. Aimi, R. Akutsu, C. Andreopoulos, I. Anghel, L. H.V. Anthony, M. Antonova, Y. Ashida, V. Aushev, M. Barbi, G. J. Barker, G. Barr, P. Beltrame, V. Berardi, M. Bergevin, S. Berkman, L. Berns, T. Berry, S. Bhadra, F. D.M. Blaszczyk, A. Blondel, S. Bolognesi, S. B. Boyd, A. Bravar, C. Bronner

Faculty Publications

Hyper-Kamiokande consists of two identical water-Cherenkov detectors of total 520 kt, with the first one in Japan at 295 km from the J-PARC neutrino beam with 2.5° off-axis angles (OAAs), and the second one possibly in Korea at a later stage. Having the second detector in Korea would benefit almost all areas of neutrino oscillation physics, mainly due to longer baselines. There are several candidate sites in Korea with baselines of 1000-1300 km and OAAs of 1°-3°. We conducted sensitivity studies on neutrino oscillation physics for a second detector, either in Japan (JD × 2) or Korea (JD + KD), …

Defining Freeway Design Capacity Based On Stochastic Observations, Siavash Shojaat, Justin Geistefeldt, Scott A. Parr, Luis Escobar, Brian Wolshon

Faculty Publications

The estimation of capacity as a parameter to assess traffic flow performance on freeway facilities has received considerable attention in the literature. Despite the general acceptance of the stochastic notion of capacity, limited research has been conducted on how to select a single representative design value from a capacity distribution function. This paper reports the results of an empirical comparison between conventional capacity estimates and those obtained by maximizing the sustained flow index (SFI) for 19 U.S. freeway sections. The SFI is defined as the product of the traffic volume and the probability of survival at this volume. The capacity …

Using Hydrogen Stable Isotope Ratios To Trace The Geographic Origin Of The Population Of Bactrocera Dorsalis (Diptera: Tephritidae) Trapped In Northern China, Zihua Zhao, Zhenglong Lu, Gadi V.P. Reddy, Shuo Zhao, Guanghui Lin, Jianyun Ding, Jiajiao Wu, Zhihong Li

Faculty Publications

The oriental fruit fly, Bactrocera dorsalis Hendel (Diptera: Tephritidae), is a generalist feeder that is known to successfully feed and breed on a variety of fruits and vegetables in the tropical and subtropical zones of Asia. Recently, the northward extension of B. dorsalis has been reported, and this geographic range increase relates to both climate changes and the rapid development of domestic and international trade and travel. However, it has not been possible to determine the origin of this pest, which is trapped in north China. In this study, traps baited with the sex attractant methyl eugenol were used to …

Reflection Negative Kernels And Fractional Brownian Motion, Palle E.T. Jorgensen, Karl Hermann Neeb, Gestur Ólafsson

Faculty Publications

In this article we study the connection of fractional Brownian motion, representation theory and reflection positivity in quantum physics. We introduce and study reflection positivity for affine isometric actions of a Lie group on a Hilbert space ε and show in particular that fractional Brownian motion for Hurst index 0 < H ≤ 1/2 is reflection positive and leads via reflection positivity to an infinite dimensional Hilbert space if 0 < H < 1/2. We also study projective invariance of fractional Brownian motion and relate this to the complementary series representations of GL2(ℝ). We relate this to a measure preserving action on a Gaussian L2-Hilbert space L2(ε).

A Theory Of Minimal K-Types For Flat G-Bundles, Christopher L. Bremer, Daniel S. Sage

Faculty Publications

The theory of minimal K-types for p-adic reductive groups was developed in part to classify irreducible admissible representations with wild ramification. An important observation was that minimal K-types associated to such representations correspond to fundamental strata. These latter objects are triples (x, r, β), where x is a point in the Bruhat-Tits building of the reductive group G, r is a nonnegative real number, and β is a semistable functional on the degree r associated graded piece of the Moy-Prasad filtration corresponding to x. Recent work on the wild ramification case of the geometric Langlands conjectures suggests that fundamental strata …

Stability And Robustness Analysis For A Multispecies Chemostat Model With Delays In The Growth Rates And Uncertainties, Frederic Mazenc, Gonzalo Robledo, Michael Malisoff

Faculty Publications

We study a chemostat model with an arbitrary number of competing species, one substrate, and constant dilution rates. We allow delays in the growth rates and additive uncertainties. Using constant inputs of certain species, we derive bounds on the sizes of the delays that ensure asymptotic stability of an equilibrium when the uncertainties are zero, which can allow persistence of multiple species. Under delays and uncertainties, we provide bounds on the delays and on the uncertainties that ensure input-to-state stability with respect to uncertainties.

A Coupled Ericksen/Allen–Cahn Model For Liquid Crystal Droplets, Angelique Morvant, Ethan Seal, Shawn W. Walker

Faculty Publications

We present a model and discretization that couples the Ericksen model of liquid crystals with variable degree of orientation to the Allen–Cahn equations with a mass constraint. The coupled system models liquid crystal droplets with anisotropic surface tension effects due to the liquid crystal molecular alignment. The total energy consists of the Ericksen energy, phase-field (Allen–Cahn) energy, and a weak anchoring energy that couples the liquid crystal to the diffuse interface. We describe our discretization of the total energy along with a method to compute minimizers via a discrete gradient flow algorithm which has a strictly monotone energy decreasing property. …

Secure Transmission With Guaranteed User Satisfaction In Heterogeneous Networks: A Two-Level Stackelberg Game Approach, Nanmiao Wu, Xiangwei Zhou, Mingxuan Sun

Faculty Publications

In this paper, secure transmission in a heterogeneous network in the presence of multiple eavesdroppers is studied. A game-theoretic framework is proposed to enhance the security of the macro base station (MBS), while guaranteeing user satisfaction of the small base stations (SBSs) by exploiting the cooperation and competition among the entire network. Specifically, a two-level Stackelberg game is formulated, where the MBS employs a set of competing jamming SBSs to jam the eavesdroppers at the top level, and each employed jamming SBS may require offloading service from multiple competing helping SBSs in its cluster at the bottom level if needed. …

Generating Audio Using Recurrent Neural Networks, Andrew Pfalz

LSU Doctoral Dissertations

Long Short Term Memory cells are a type of recurrent neural network that perform well when predicting sequence data. This works presents four approaches to modeling audio data. The models are trained to predict either raw audio samples or magnitude spectrum windows based on prior input audio. In a process called sampling, the models can then be employed to generate new audio using what they learned about the data they were trained on.

Four methods for sampling are presented. The first has the model predict a vector for each vector in the input. The second has the model predict one …

A Novel Multiproxy Approach To Reconstructing Sea Surface Temperature In The Southwestern Gulf Of Mexico, Marissa Anne Vara

LSU Master's Theses

Coral Sr/Ca is a widely-used proxy for sea surface temperature (SST); however, discrepancies in the coral Sr/Ca-SST relationship among colonies of the same species makes uncertainty in absolute temperature reconstructions larger than the climate signal yet climate variability studies are possible. Furthermore, the riverine input of terrestrial carbonate weathering products to the coastal waters can disrupt the coral Sr/Ca-SST signal by changing local seawater chemistry. This study evaluates the fidelity and reproducibly of coral SST proxies (Sr/Ca, Li/Ca, Mg/Li, Sr-U, Mg/Ca, and U/Ca) and a riverine-upwelling proxy (Ba/Ca) in four Orbicella faveolata colonies in two reefs offshore from Veracruz, Mexico …

Risk Assessment Of Concrete Gravity Dams Under Earthquake Loads, Ufuk Sen

LSU Master's Theses

Dams are important structures to supply water for irrigation or drinking, to control flood, and to generate electricity. In seismic regions, the structural safety of concrete gravity dams is important due to the high potential of life and economic loss if they fail. Therefore, the seismic analysis of existing dams in seismically active regions is very crucial to predict responses of dams to ground motions. In this thesis, earthquake response of concrete gravity dams is investigated using the finite element (FE) method. The selected dam is the Pine Flat Dam which is located in the Central Valley of Fresno County, …