Digital Commons Network^™

Effect Of Long-Term Caloric Restriction On Telomere Length In Healthy Adults: Calerie™ 2 Trial Analysis, Waylon J. Hastings, Qiaofeng Ye, Sarah E. Wolf, Calen P. Ryan, Sai Krupa Das, Kim M. Huffman, Michael S. Kobor, William E. Kraus, Julia L. Macisaac, Corby K. Martin, Susan B. Racette, Leanne M. Redman, Daniel W. Belsky, Idan Shalev

Clinical Research Faculty Publications

Caloric restriction (CR) modifies lifespan and aging biology in animal models. The Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy (CALERIE™) 2 trial tested translation of these findings to humans. CALERIE™ randomized healthy, nonobese men and premenopausal women (age 21–50y; BMI 22.0–27.9 kg/m2), to 25% CR or ad-libitum (AL) control (2:1) for 2 years. Prior analyses of CALERIE™ participants' blood chemistries, immunology, and epigenetic data suggest the 2-year CR intervention slowed biological aging. Here, we extend these analyses to test effects of CR on telomere length (TL) attrition. TL was quantified in blood samples collected at baseline, 12-, …

Recovery Of The X-Ray Polarisation Of Swift J1727.8-1613 After The Soft-To-Hard Spectral Transition, J. Podgorný, J. Svoboda, M. Dovčiak, A. Veledina, J. Poutanen, P. Kaaret, S. Bianchi, A. Ingram, F. Capitanio, S. R. Datta, E. Egron, H. Krawczynski, G. Matt, F. Muleri, P. O. Petrucci, T. D. Russell, J. F. Steiner, N. Bollemeijer, M. Brigitte, N. Castro Segura, R. Emami, J. A. García, K. Hu, M. N. Iacolina, V. Kravtsov, L. Marra, G. Mastroserio, T. Muñoz-Darias, E. Nathan, M. Negro, A. Ratheesh, N. Rodriguez Cavero, R. Taverna

Faculty Publications

We report on the detection of X-ray polarisation in the black-hole X-ray binary Swift J1727.8-1613 during its dim hard spectral state by the Imaging X-ray Polarimetry Explorer (IXPE). This is the first detection of X-ray polarisation at the transition from the soft to the hard state in an X-ray binary. We find an averaged 2- 8 keV polarisation degree of (3.3 ± 0.4)% and a corresponding polarisation angle of 3 ±4, which matches the polarisation detected during the rising stage of the outburst, in September- October 2023, within 1σuncertainty. The observational campaign complements previous studies of this source and enables …

Assessing The Long-Term Effects Of Conservation Agriculture On Cotton Production In Northeast Louisiana Using The Denitrification–Decomposition Model, Janntul Ferdush, Changyoon Jeong, Hwangju Jeon, Jim Wang, Kyoung Ro, Xi Zhang, Meesook Lee

Faculty Publications

Conservation agriculture (CA) aims to sustain agricultural production, soil, and environmental health in agroecosystems and has been promoted throughout the United States. The adoption of CA in cotton (Gossypium hirsutum) systems provides both agronomic and environmental benefits. Yet, there is limited information on the long-term effects of CA practices on crop yield and adaptation strategies. An integrated CA system, that is, cover crops with no-tillage (NT) instead of conventional agriculture, was implemented in the long-term field experiments and assessed with an integrated biogeochemical model. Using the denitrification–decomposition model, this study estimated the effects of four different cover crops, for example, …

Borehole-Based Interval Kriging For 3d Lithofacies Modeling, Yuqi Song, Frank T.C. Tsai

Faculty Publications

Developing a three-dimensional (3D) lithofacies model from boreholes is critical for providing a coherent understanding of complex subsurface geology, which is essential for groundwater studies. This study aims to introduce a new geostatistical method—interval kriging—to efficiently conduct 3D borehole-based lithological modeling with sand/non-sand binary indicators. Interval kriging is a best linear unbiased estimator for irregular interval supports. Interval kriging considers 3D anisotropies between two orthogonal components—a horizontal plane and a vertical axis. A new 3D interval semivariogram is developed. To cope with the nonconvexity of estimation variance, the minimization of estimation variance is regulated with an additional regularization term. The …

Molecular-Level Studies Of Nanopatterned Biomolecules With Atomic Force Microscopy, Ashley R. Walker

LSU Doctoral Dissertations

Atomic force microscopy (AFM) is an analytical technique in which a tipped probe is gently scanned across the surface in a raster pattern to generate digital images of a sample at the nanoscale. The AFM instrument has three general operational modes, which are contact, non-contact and tapping-mode, that can be used to examine materials at the atomic level. Single-molecular details of biological molecules and other soft organic materials can be captured with minimal denaturation in either ambient or liquid environments when using tapping-mode AFM. In tapping-mode, the probe is driven to oscillate vertically while the tip is scanned across the …

Comparing Editorial And Artificially Generated Fingerings: A Case Study, Lixi Qin

LSU Doctoral Dissertations

Fingering is crucial for piano performance. Unlike other instruments with relatively fixed fingerings, keyboard instruments offer countless fingering combinations. As musical styles have evolved, so too have the instruments themselves, resulting in a rich history of diverse fingering systems, which sometimes conflict with one another. Moreover, due to individual differences in hand shape and size, the fingering advice from editors or teachers may not be universally applicable, and there is a lack of an objective, unified standard for validating these recommendations.

For students who do not fully understand fingering principles and have not been exposed to a wide range of …

Scaling The Wall: Math Attitudes And Mindsets Of Middle School High-Achievers, Stephanie R. Gullage

LSU Doctoral Dissertations

This intrinsic case study examined groups of gifted and high achieving middle school mathematics students in one school’s advanced and honors program. The purpose of this study was to determine how the students view themselves in light of noncognitive constructs, how they regard and apply those constructs in their mathematics studies, how the work of those constructs can affect their attitudes toward mathematics, and how they believe educators can help foster success in math via noncognitive factors. The researcher employed a questionnaire, observations, focus group interviews, and interviews with key informants to gather study data. With the theoretical lenses of …

Optimal Planning And Design Of Operations And Maintenance Systems For Offshore Wind Farms, Md Imran Hasan Tusar

LSU Doctoral Dissertations

Feasible and sustainable sources of power are a critical issue nowadays. Offshore wind farms (OWF) can be a solution to power generation problems, but it is relatively more expensive— their installation cost is more than twice of their comparable size onshore counterparts. The cost that matters most is the operations and maintenance (O&M) cost. Expensive and sophisticated transfer vehicles and highly skilled technicians are needed to conduct O&M activities, resulting in a remarkably higher O&M cost for an offshore wind farm project. Offshore wind turbines can capture more wind than onshore turbines because of their larger structure and location in …

Learning Proximal Operators With Gaussian Process And Adaptive Quantization In Distributed Optimization, Aldo Duarte Vera Tudela

LSU Doctoral Dissertations

In networks consisting of agents communicating with a central coordinator and working together to solve a global optimization problem in a distributed manner, the agents are often required to solve private proximal minimization subproblems. Such a setting often requires a further decomposition method to solve the global distributed problem, resulting in extensive communication overhead. In networks where communication is expensive, it is crucial to reduce the communication overhead of the distributed optimization scheme. Integrating Gaussian processes (GP) as a learning component to the Alternating Direction Method of Multipliers (ADMM) has proven effective in learning each agent's local proximal operator to …

Optics Design And Fabrication For A Lung Interferometry-Radiography System, Rachael Lyn Blair

LSU Master's Theses

Purpose: High prevalence of lung diseases leads to many people worldwide needing spirometry and imaging testing. The typical imaging done uses chest radiography and/or low-dose CT. Lung tissue is difficult to visualize, making them substandard for monitoring lung disease progression. An improvement on these systems is x-ray interferometry which produces additional images that provide better visualization of changes in the lung tissue. The set-up of x-ray interferometry builds upon other imaging systems in that it includes diffraction gratings.

Materials: This thesis focused on implementing the fabrication processes to create diffraction gratings for a lung imager prototype that is currently under …

Decay Spectroscopy Of 134sb Using X-Array And Saturn, Graeme E. Morgan

LSU Doctoral Dissertations

The ground-state decay of ¹³⁴Sb is reported by the current evaluated nuclear data to be dominated by a 0^-→0⁺ first-forbidden Gamow-Teller transition to the ground state of ¹³⁴Te. In 2013, a recoil-ion time-of-flight (RI-TOF) spectroscopy measurement of ¹³⁴Sb with the Beta-decay Paul Trap (BPT) indicated that the ground-state feeding of ¹³⁴Te is weaker than reported. Simulation work of ¹³⁴Sb ground-state decays replicated the RI-TOF results with the addition of a theorised 5-MeV state that was fed with ~17% of the total β-decay strength. To search for higher energy states and transitions that …

Struggling To Be Positive Problem Solvers – A Study On The Relationship Of Elementary Mathematical Self-Concept, Gender, Learner Identification, And Productive Struggle Trajectories On Constructed Response Questions When Being Taught With A Standardized Curriculum, Kali D. Rogers

LSU Doctoral Dissertations

Mathematical word problems are some of the most difficult problems for students to solve due to their complexity and relationship to real-world situations (Şahin et al., 2014; Verschaffel et al., 2020). With math being known for right-or-wrong answers, these open-ended questions cause much confusion and frustration, specifically for students of various subgroups. In the last several decades, educational teaching expectations have shifted from engaging, self-created learning to robotic and redundant curriculum expectations that induce a ‘teaching to the test’ environment (Shafiyeva, 2021). Mathematics is the powerhouse of where students can experience and succeed with productive struggle learning that teaches the …

Coordination Numbers And Grain Texture From Micro-Xray Tomography Of Angular Unconsolidated Sediments: Velocity Prediction Using Hertz-Mindlin Model., Kwabena Poku-Agyemang

LSU Master's Theses

Elastic properties of unconsolidated sediments depend on parameters such as porosity, grain texture (i.e., grain shape and sizes), sorting and coordination number. Coordination is the average number of grains each grain has with touching grains, is a critical parameter in rock physics models for estimating elastic moduli of materials. While previous works have focused on the influence of porosity and sorting on coordination numbers within well-rounded grains, natural sediments have a wide range of grain shapes and sizes, and it remains unclear how these parameters influence coordination numbers within angular unconsolidated sediments.

We investigate the impact of porosity, sorting and …

Examining The Use Of Vr As A Study Aid For University Students With Adhd, Isabelle Cuber, Juliana G. Goncalves De Souza, Irene Jacobs, Caroline Lowman, David Shepherd, Thomas Fritz, Joshua M. Langberg

Faculty Publications

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition characterized by patterns of inattention and impulsivity, which lead to difficulties maintaining concentration and motivation while completing academic tasks. University settings, characterized by a high student-to-staf ratio, make treatments relying on human monitoring challenging. One potential replacement is Virtual Reality (VR) technology, which has shown potential to enhance learning outcomes and promote fow experience. In this study, we investigate the usage of VR with 27 university students with ADHD in an efort to improve their performance in completing homework, including an exploration of automated feedback via a technology probe. Quantitative results show significant …

Examining The Authenticity Of The 'Ether Model' In Certain O-Glycosylation Reactions, Varad Vinayak Agarkar

LSU Doctoral Dissertations

Acinetobacter baumannii is a gram-negative bacterium species that is responsible for nosocomial infections. It has shown antibiotic resistance and has been designated an urgent threat by the CDC. In Chapter 1, I highlight my efforts in the synthesis of a Kdo building block in the journey towards the construction of an A. baumannii lipooligosaccharide (LOS) core pentasaccharide- a potential candidate for glycoconjugate vaccine against A. baumannii infection. I talk about various optimizations and improvements in the Kdo monosaccharide synthesis and the mechanistic insights I provided about a critical transformation in the synthetic sequence.

Chemical O-glycosylation is a significant research …

Multiphoton Quantum Sensing, Fatemeh Mostafavikhatam

LSU Doctoral Dissertations

While the fundamental principles of light-matter interaction are well-understood and drive countless technologies, the world of multiphoton processes remains a fascinating puzzle, holding the potential to drastically alter our understanding of how light interacts with matter at its most basic level [1–4]. This rich interplay of light and matter unveils novel phenomena that can be harnessed for sensing with exceptional precision, as exemplified by multiphoton quantum sensing. This thesis delves into the applications of multiphoton quantum protocols, particularly in imaging, communication, and plasmonic sensing, to surpass classical limitations and achieve enhanced sensitivity. We explore the potential of multiphoton quantum processes, …

Energy Compensation For Crop Growth Under Plastic Mulching: Theories, Models, And Limitations, Dianyuan Ding, Ting Li, Lihong Wu, Xi Zhang, Ying Zhao, Hao Feng, Chao Zhang, Ole Wendroth

Faculty Publications

Plastic film mulching (PM) is a useful agronomic means to adapt to the environmental conditions of dryland agriculture and improve crop production. To improve the theoretical framework of PM technology, this study focuses on the interaction between the soil temperature change caused by PM and crop growth. The definition, action mechanism, and simulation of the compensatory effect of PM on growing degree days are introduced to reveal the effect of soil temperature under PM on crop development and growth. Our summary shows that the strength of the warming effect changes with the growth and development of crops, strengthening during the …

Twisting Manin's Universal Quantum Groups And Comodule Algebras, Hongdi Huang, Van C. Nguyen, Charlotte Ure, Kent B. Vashaw, Padmini Veerapen, Xingting Wang

Faculty Publications

We introduce the notion of quantum-symmetric equivalence of two connected graded algebras, based on Morita–Takeuchi equivalences of their universal quantum groups, in the sense of Manin. We study homological and algebraic invariants of quantum-symmetric equivalence classes, and prove that numerical Tor-regularity, Castelnuovo–Mumford regularity, Artin–Schelter regularity, and the Frobenius property are invariant under any Morita–Takeuchi equivalence. In particular, by combining our results with the work of Raedschelders and Van den Bergh, we prove that Koszul Artin–Schelter regular algebras of a fixed global dimension form a single quantum-symmetric equivalence class. Moreover, we characterize 2-cocycle twists (which arise as a special case of …

A Reciprocal Integral Identity Of Coupled Poisson And Laplace Equations In Two Arbitrary Domains Sharing A Common Boundary, Sai Sashankh Rao, Harris Wong

Faculty Publications

In solving the coupled vapor and liquid unidirectional flows in micro heat pipes, we discovered numerically an integral identity. After asymptotic and polynomial expansions, the coupled flows yield two reciprocal systems of equations. In system A, a vapor velocity UA obeys the Poisson equation and drives, through an interfacial boundary condition, a liquid velocity WA that satisfies the Laplace equation. In reciprocal system B, a liquid velocity WB obeys the Poisson equation and drives, through another interfacial boundary condition, a vapor velocity UB that satisfies the Laplace equation. We found that the vapor volume flow rate of UB is numerically …

Molybdenum Alkylidyne Complexes With Phenoxide Ligands For Alkyne Metathesis, Marvin L. Stewart Jr

LSU Doctoral Dissertations

Abstract

Alkyne metathesis is a powerful synthetic tool, which provides easy access to complex organic molecules in a single-step. It is a dynamic covalent reaction that scrambles alkynes, carbon-carbon triple bonds (C≡C). Molybdenum- or tungsten-alkylidyne (Mo≡C, W≡C) complexes are typically used as catalyst to cleave and reform alkyne bonds. Our goal has been to gain a deeper understanding of the intrinsic differences between functional ligands by the development of novel phenoxide ligands.

In chapter 2 we explore the detailed synthesis of novel phenoxide podand ligands in an effort to identify their mo-alkylidyne complexes. We were able to synthesize a variety …

Benthic Community Response To The Impacts Of Proposed Sediment Diversions In Louisiana Estuaries, Jillian C. Tupitza

LSU Doctoral Dissertations

Sediment diversions designed to mitigate land loss in coastal Louisiana will likely cause ecosystem-wide shifts. The first diversion, planned for Barataria Bay, will divert fresh water and sediment from the Mississippi River into the surrounding wetlands to help them keep pace with high rates of relative sea-level rise (RSLR). Estuarine benthic communities were used in this study as tools to characterize ecological patterns in the context of anticipated salinity changes. I reviewed relevant literature, conducted a two-year survey of Barataria Bay benthos, executed a reciprocal transplant experiment to describe changes that might occur in both community composition and trophic dynamics, …

The Lowest Discriminant Ideal Of Cayley-Hamilton Hopf Algebras, Zhongkai Mi

LSU Doctoral Dissertations

Discriminant ideals are defined for an algebra R with central subalgebra C and trace tr : R → C. They are indexed by positive integers and more general than discriminants. Usually R is required to be a finite module over C. Unlike the abundace of work on discriminants, there is hardly any literature on discriminant ideals. The levels of discriminant ideals relate to the sums of squares of dimensions of irreducible modules over maximal ideals of C containing these discriminant ideals. We study the lowest level when R is a Cayley-Hamilton Hopf algebra, i.e. C is also a Hopf subalgebra, …

Analysis Of Close Contact Melting, Mohana Durga Gurunadhan

LSU Master's Theses

This report presents a numerical transient analysis of Close Contact Melting (CCM), intended to help in accurate prediction of melt rate and interface configuration, which is to be utilized for a prospective frozen propellant based propulsion system. Three different substrate shapes namely- Flat, Cylindrical and Wedge, are chosen for the study. The domain discretization is based on generation of boundary fitted mesh and the time varying physical domain is transformed to a fixed computational domain, wherein the associated governing equations are solved. Apart from the conventional linear system solvers, an algebraic multigrid based solver is implemented. A non-iterative implicit/explicit melt …

Improved Modeling And Application Of Data Assimilation In Gas Influx Management During Managed Pressure Drilling, Chen Wei

LSU Doctoral Dissertations

The management of gas influxes in a drilling well has been considered one of the most critical topics for maintaining petroleum drilling safety and efficiency. Reliable modeling of gas influx behaviors in a wellbore or a marine riser greatly benefits the improved understanding of a gas kick event and the development of optimized influx management strategies. However, the current studies on transient multiphase flow modeling show varying limitations on both the model rigorousness and the overall numerical efficiency. Meanwhile, the existence of great system uncertainties, such as the unclear influx sizes and distributions in the well/riser, has brought significant challenges …

Research On 3d Printing Resin Exposure Properties And Its Application On Centrifugal Microfluidic Platform Based On Fluorescence Detection, Zheng Qiao

LSU Doctoral Dissertations

This dissertation encapsulates significant advancements in the field of SLA 3D printing and centrifugal microfluidics. Central to the research is the development of a novel mathematical model for predicting trapped resin thickness in SLA 3D printing, a groundbreaking contribution that addresses a critical aspect of printing intricate structures. This model, the first to establish a mathematical relationship for resin thickness, is rooted in a comprehensive study of the resin curing process. The research leverages the concept of 'critical dosage' for resin curing, leading to a more refined and theoretically grounded approach for calculating curing thickness. Experimentation further validates the model, …

All-Optical Probes Of Particle-Like Charge Migration Dynamics, Kyle A. Hamer

LSU Doctoral Dissertations

Particle-like charge migration (CM) is the coherent, back-and-forth motion of a positively-charged electron hole along the backbone of a molecule following a sudden ionization. CM in small molecules generally occurs on an Angstrom (10^-10 m) spatial scale and an attosecond (10^-18 s) timescale. I use time-dependent density-functional theory (TDDFT) to simulate CM modes in organic molecules, and to explore all-optical probes of this attosecond electron dynamics using high-harmonic spectroscopy (HHS). By leveraging my results from previous studies of two-center interferences in carbon dichalcogens, in which I separated the harmonic signal into contributions from individual Kohn-Sham orbitals, I first …

Post-Modeling Adjustments And Delivered Dose Verification Of The 6fff Beam Model Commissioned For The Monaco Treatment Planning System, Grant C. Debevec

LSU Master's Theses

External beam radiation therapy has been shown to be an effective treatment method for tumors and abnormalities of the spine and vertebral region. Treating the spine using a stereotactic body radiation therapy (SBRT) technique can reduce toxicity to the spinal cord. The 6 MV flattening filter free (6FFF) beam model is currently used to plan and calculate dose for SBRT treatment plans, and the treatment plans are delivered using a linear accelerator (LINAC).

The commissioned beam model represents an invariant component of a LINAC. For volumetric modulated arc therapy (VMAT) treatment plans, the multileaf collimator (MLC) positions are changing throughout …

Phonic Faces As An Intervention To Improve Decoding Skills Of Children With Persistantly Poor Decoding Abilities, Kayla Therese Martin

LSU Master's Theses

Background: Orthographic rules, phonological awareness, and the ability to process morphemes and phonemes from speech and language begins with verbal speech and the child unknowingly recognizes words from his or her environment as early as the senses can process their surroundings. Some children have difficulty integrating these processes to learn how to read. As Ehri (1979) mentions the importance of establishing mental processes, such as amalgamation and phonological recoding, are essential as a basis for establishing reading fundamentals. Decoding occurs through a complex integration of phonological and orthographic knowledge (Ehri 1992). Early readers typically have well-established amalgams for spoken words …

Examination Of The Effects Of Ultraviolet Radiation On The Toxicity Of An Array Of Pesticides, Polyaromatic Hydrocarbons, And Pharmaceuticals Via In-Vitro Bioassays, Jessica R. Stephens

LSU Master's Theses

Chemicals are often released via anthropogenic means both intentionally and unintentionally into aquatic environments. The chemical fate of these compounds can vary greatly depending on numerous factors that can include but are not limited to salinity, pH, dissolved oxygen, and exposure to ultraviolet radiation. The goal of this study was to investigate the effect of UV radiation on the level of toxicity of different chemicals over time. Chemicals were selected based on previous studies of the toxicity of both parent and metabolites formed as a result of photolysis. Anthracene, phenanthrene, anthraquinone, dicloran, chlorothalonil, hydroxy chlorothalonil, benzobicyclon hydrolysate, and sertraline were …

Reducibility Of Schrödinger Operators On Multilayer Graphs, Jorge Villalobos Alvarado

LSU Doctoral Dissertations

A local defect in an atomic structure can engender embedded eigenvalues when the associated Schrödinger operator is either block reducible or Fermi reducible, and having multilayer structures appears to be typically necessary for obtaining such types of reducibility. Discrete and quantum graph models are commonly used in this context as they often capture the relevant features of the physical system in consideration.

This dissertation lays out the framework for studying different types of multilayer discrete and quantum graphs that enjoy block or Fermi reducibility. Schrödinger operators with both electric and magnetic potentials are considered. We go on to construct a …