Digital Commons Network^™

Genome Wide Association Studies For Identification Of Markers Linked To Sucrose Traits In Sugarcane, Nathanael Darrell Fickett

LSU Doctoral Dissertations

Sugarcane, being a complex aneu-polyploid, poses unique challenges to fine mapping of quantitative trait loci (QTL) controlling agronomic traits of interest. Genome-wide association studies (GWAS) could be a better alternative to identify molecular markers associated with specific traits due to high linkage disequilibrium in sugarcane. In the first study, marker-trait associations (MTAs) were evaluated for three sucrose traits, Brix, total recoverable sugar (TRS), and percent sucrose on 48 elite and historic Louisiana breeding clones using 1,062 alleles. These sucrose traits were highly correlated (P-value < 0.0001) at >0.96. TASSEL 5.1 and JMP Genomics 8.0 were compared with eight models run in each program. …

Tidal-, Wind-, And Buoyancy-Driven Dynamics In The Barataria Estuary And Its Impact On Estuarine-Shelf Exchange Processes, Linlin Cui

LSU Doctoral Dissertations

A three-dimensional, high-resolution, Finite-Volume Coastal Ocean Model (FVCOM) was used to study the dynamics of Barataria Estuary located in the Southeastern Louisiana. Three numerical experiments with different discharge scenarios, including the actual discharge (average ~ 160 m³ s^-1) from the Davis Pond Diversion (DPD) over three months from April to June 2010, no discharge (NO), and the proposed Mid-Barataria Diversion (MBD) with a constant discharge of 850 m³ s^-1, were conducted to investigate the impacts of river diversions on salinity gradients and residence times in the estuary. The three-month average salinity indicated that surface …

First-Principles Study On The Catalytic Role Of Cerium Dioxide In The Conversion Of Organic Compounds, Chuanlin Zhao

LSU Doctoral Dissertations

Ceria is an earth-abundant material that has been widely used in heterogeneous catalysis, environmental catalysis, and energy applications thanks for its ability to readily convert between different oxidation states. The objective of this study is to theoretically elucidate the reaction mechanisms for the conversion of model organic compounds on ceria, in order to gain insights for the design of cost-effective and selective ceria-based catalysts. Acetaldehyde, acetic acid, and para-nitrophenyl phosphate monoester were selected as the model compounds to probe ceria surfaces. Density functional theory calculations can provide accurate predictions of adsorption and reaction energetics, which can be used to …

Induced Resistance In Rice, Oryza Sativa, To Herbivores In The Southern United States, Emily Clare Kraus

LSU Doctoral Dissertations

The effects of herbivory and chemical applications as potential inducers of resistance to herbivores in rice, Oryza sativa L., were explored through a series of field, greenhouse, and laboratory experiments. Studies were conducted to investigate the preference and performance of several herbivore pests of rice with a focus on, Lissorhoptrus oryzophilus Kuschel, the rice water weevil (RWW), under conditions where rice plants had been stressed by previous herbivory or chemical applications. The effects of defoliation by Spodoptera frugiperda (J.E. Smith), the fall armyworm, on resistance and tolerance of rice to RWW under field conditions were examined. Herbivory by fall …

Large Eddy Simulations Of Vertical Jets In Crossflow, Pranaya Pokharel

LSU Doctoral Dissertations

Jets in crossflow (JICF) have applications ranging from oil spill to film cooling of turbine blades. Hence, an understanding of the flow physics is important. The majority of the research has been conducted for low velocity ratios between jet and crossflow with round jets. JICF is demonstrated to behave differently for high velocity ratios and different jet shapes. Circular and rectangular jets are commonly used in aircraft applications. Current study focuses on high velocity ratio JICF issuing from both circular and rectangular exit.

For simulating JICF, an in house code “Chem3D” is used with Large Eddy Simulation (LES) to model …

Effective Visualization Approaches For Ultra-High Dimensional Datasets, Gurminder Kaur

LSU Doctoral Dissertations

Multivariate informational data, which are abstract as well as complex, are becoming increasingly common in many areas such as scientific, medical, social, business, and so on. Displaying and analyzing large amounts of multivariate data with more than three variables of different types is quite challenging. Visualization of such multivariate data suffers from a high degree of clutter when the numbers of dimensions/variables and data observations become too large. We propose multiple approaches to effectively visualize large datasets of ultrahigh number of dimensions by generalizing two standard multivariate visualization methods, namely star plot and parallel coordinates plot. We refine three variants …

Out Of The Shadows The Matriarch Rises: A Case Study Of Women Academic Deans At A Southern, Research One Institution, Jacob Lee Vaughn

LSU Doctoral Dissertations

Abstract

This study examined the experiences of women in higher education as a career as well as the challenges women face in pursuing an appointment as Dean of a college. Selected participants were interviewed to gather data from their own narratives about the experiences and challenges as current women Deans in higher education. Each participant attributed their success to family support and proper mentoring, while highlighting institutional policies acting as a form of gendered oppression. Recommendations were suggested to higher educational representatives and legislators concerning the correction of the gendered environment favoring the advancement of men into a more equitable …

Soybean Response To Dicamba: Associated Injury Criteria And Development Of A Model To Predict Yield Loss, Matthew Ryan Foster

LSU Doctoral Dissertations

In research conducted using indeterminate soybean [Glycine max (L.) Merr.], fourteen injury criteria observed following dicamba at 0.6 to 280 g ae ha^-1 (1/1000 to ½ of 560 g ha^-1 use rate) were rated using a scale of 0= no injury, 1= slight, 2= slight to moderate, 3= moderate, 4= moderate to severe, and 5= severe. Greatest crop injury 15 d after treatment (DAT) was observed following dicamba applied at 0.6 to 4.4 g ha^-1 at V3/V4 for upper canopy pale leaf margins (3.8 to 4.2) and at R1/R2 for terminal leaf cupping (4.1 to 5.0) …

Reinforcement Learning In Robotic Task Domains With Deictic Descriptor Representation, Harry Paul Moore

LSU Doctoral Dissertations

In the field of reinforcement learning, robot task learning in a specific environment with a Markov decision process backdrop has seen much success. But, extending these results to learning a task for an environment domain has not been as fruitful, even for advanced methodologies such as relational reinforcement learning. In our research into robot learning in environment domains, we utilize a form of deictic representation for the robot’s description of the task environment. However, the non-Markovian nature of the deictic representation leads to perceptual aliasing and conflicting actions, invalidating standard reinforcement learning algorithms. To circumvent this difficulty, several past research …

Observation Of High-Energy Gamma-Rays With The Calorimetric Electron Telescope (Calet) On-Board The International Space Station, Nicholas Wade Cannady

LSU Doctoral Dissertations

The CALorimetric Electron Telescope (CALET) is a multi-instrument high-energy astrophysics observatory deployed to the International Space Station (ISS) in August 2015. The primary instrument is the calorimeter (CAL), which is intended for measurement of the cosmic ray electron flux in the energy range 10 GeV - 20 TeV. The CAL is also sensitive to gamma-rays in the energy range 1 GeV - 10 TeV and protons and nuclei up to PeV energies. Also present on the CALET payload are an Advanced Stellar Compass (ASC) for the fine determination of the pointing direction and the CALET Gamma-ray Burst Monitor (CGBM) for …

Thermal And Mechanical Energy Harvesting Using Lead Sulfide Colloidal Quantum Dots, Taher Ghomian

LSU Doctoral Dissertations

The human body is an abundant source of energy in the form of heat and mechanical movement. The ability to harvest this energy can be useful for supplying low-consumption wearable and implantable devices. Thermoelectric materials are usually used to harvest human body heat for wearable devices; however, thermoelectric generators require temperature gradient across the device to perform appropriately. Since they need to attach to the heat source to absorb the heat, temperature equalization decreases their efficiencies. Moreover, the electrostatic energy harvester, working based on the variable capacitor structure, is the most compatible candidate for harvesting low-frequency-movement of the human body. …

Evaluation Of Oral Function Before And After Frenectomy In Breastfed Infants Diagnosed With Tethered Oral Tissue, Cindy L. Parr

LSU Doctoral Dissertations

Assessment and treatment of tethered oral tissue, or tongue tie, vary within and across providers, resulting in inconsistent surgical and therapeutic outcomes. Assessment and treatment have historically focused on the anatomical (structural) underpinnings of tongue tie, as opposed to the physiological (functional) aspects that can affect daily activities. This is particularly noteworthy in the infant population in regards to breastfeeding. Clinical findings, however, suggest that connections exist between tongue tie and a variety of other oral functions that go beyond breastfeeding. The goal of this research was to examine a relatively small group of breastfed infants with tethered oral …

Influence Of Salinity, Sunlight, And Sediment On The Toxicity Of Pesticides In Three Non-Target Organisms, Emily Noelle Vebrosky

LSU Doctoral Dissertations

Pesticides used in the United States must undergo registration by the United States Environmental Protection Agency (USEPA), after a multitude of analyses ranging from environmental fate to aquatic toxicological impacts to human risk exposure. Testing varies for each chemical, some requiring more testing than others. In many cases, environmental factors are restricted in the analysis of chemical behavior and organismal testing is limited to larvae. Many pesticides are formulated to breakdown in the environment by means of photolysis, hydrolysis, or oxidation, either to ensure low-persistence, limited transport, or to form the active ingredient (pro-pesticides). Environmental influences on chemical behaviors include …

Landscapes Of Persistence And Ritual Architecture At The Cosma Complex, Upper Nepeña Valley, Peru., Kimberly Elizabeth Munro

LSU Doctoral Dissertations

This dissertation focuses on the Cosma Complex, a multi-component archaeological site located at the headwaters of the Nepeña River, on the western slopes of the Cordillera Negra in the modern Department of Ancash, Peru. The overarching goal of this study is to understand not only Cosma’s influence as a religious center within the Nepeña Valley and the surrounding region, but its recurring occupation over a 5000-year time span and its role in religious networks within the valley through its function as a cultural landscape resource or persistent place.

The Cosma complex extends over 250 hectares and includes two multi-storied temple …

Effective Methods And Tools For Mining App Store Reviews, Nishant Jha

LSU Doctoral Dissertations

Research on mining user reviews in mobile application (app) stores has noticeably advanced in the past few years. The main objective is to extract useful information that app developers can use to build more sustainable apps. In general, existing research on app store mining can be classified into three genres: classification of user feedback into different types of software maintenance requests (e.g., bug reports and feature requests), building practical tools that are readily available for developers to use, and proposing visions for enhanced mobile app stores that integrate multiple sources of user feedback to ensure app survivability. Despite these major …

Partner Gender As A Predictor Of Relationship Satisfaction, Sexual Satisfaction, Relationship Commitment, And Attachment Identity Among Women, Amy Leigh Wright

LSU Doctoral Dissertations

Previous research examining overall relationship satisfaction, relationship commitment, and sexual satisfaction among heterosexual women is well-documented. The theoretical foundation of attachment has also been well-established within relationship research among heterosexual women. However, little to no published reports examine such variables among women currently in same-sex relationships. Furthermore, virtually no reports assess for any differences in attachment identity based on the gender of women’s romantic partners. This study therefore sought to identify any interrelationships between relationship satisfaction, relationship commitment, sexual satisfaction, and attachment identity (measured using the dimensions of avoidance and anxiety) among two groups of women based on their partner’s …

Three-Dimensional Flow, Morphologic Change, And Sediment Deposition And Distribution Of Actively Evolving Neck Cutoffs Located On The White River, Arkansas, Derek Allen Richards

LSU Doctoral Dissertations

Neck cutoffs are important and prominent features of alluvial rivers yet detailed field-based research of neck cutoffs has been insufficient to fully characterize three-dimensional flow, morphologic change, and sediment deposition and distribution. The main objectives of this research are to examine the formation and evolution of neck cutoffs by characterizing the flow field, morphology, and sediment distribution through neck cutoffs with complex planform configurations located on the White River, Arkansas. Results led to the production of two conceptual models. The flow model has main hydrodynamic characteristics of (1) tight bend flow resulting from flow redirection of nearly 180° through the …

The Relationship Between The High-Impact Practice Of Communication-Intensive Courses And Undergraduate Degree Completion At A Research University (Ru/Vh), Rebecca Acosta Burdette

LSU Doctoral Dissertations

With a critical public lens on quality student learning inclusive of 21^st century communication skills, and organizational effectiveness à la retention and graduation rates, all amidst budget constraints and increasing enrollments, postsecondary institutions must adopt practices that are both efficient and effective. This study examined the educational practice of Communication‑Intensive (C-I) courses and its influence on the institutional outcome of undergraduate degree completion at a large, public research university.

In this longitudinal study, the researcher applied a quantitative ex post facto research design to analyze six years of official university data on undergraduates who entered the selected university as …

Crash/Near-Crash: Impact Of Secondary Tasks And Real-Time Detection Of Distracted Driving, Peter Ramzy Zaki Bakhit

LSU Doctoral Dissertations

The main goal of this dissertation is to investigate the problem of distracted driving from two different perspectives. First, the identification of possible sources of distraction and their associated crash/near-crash risk. That can assist government officials toward more informed decision-making process, allowing for optimized allocation of available resources to reduce roadway crashes and improve traffic safety. Second, actively counteracting the distracted driving phenomenon by quantitative evaluation of eye glance patterns.

This dissertation research consists of two different parts. The first part provides an in-depth analysis for the increased crash/near-crash risk associated with different secondary task activities using the largest real-world …

Machine Learning Tools For Optimization Of Fuel Consumption At Signalized Intersections In Connected/Automated Vehicles Environment, Saleh Ragab Mousa

LSU Doctoral Dissertations

Researchers continue to seek numerous techniques for making the transportation sector more sustainable in terms of fuel consumption and greenhouse gas emissions. Among the most effective techniques is Eco-driving at signalized intersections. Eco-driving is a complex control problem where drivers approaching the intersections are guided, over a period of time, to optimize fuel consumption. Eco-driving control systems reduce fuel consumption by optimizing vehicle trajectories near signalized intersections based on information of the SpaT (Signal Phase and Timing). Developing Eco-driving applications for semi-actuated signals, unlike pre-timed, is more challenging due to variations in cycle length resulting from fluctuations in traffic demand. …

Iron-Sulfur Cluster Biogenesis And Iron Homeostasis In Escherichia Coli, Jing Yang

LSU Doctoral Dissertations

Iron-sulfur clusters as key cofactors are involved in multiple cellular processes, such as central metabolism and respiration, gene regulation and DNA repair. In Escherichia coli, iron-sulfur clusters are assembled by a group of dedicated proteins. While the sulfide in iron-sulfur clusters is derived from L-cysteine via cysteine desulfurase IscS, the iron source still remains unknown. It has been proposed that IscA and its paralog SufA may act as iron chaperones for iron-sulfur cluster biogenesis. The first part of this work focuses on the interplay between cysteine desulfurase IscS and iron chaperons IscA/SufA. The results show that deletion of IscA/SufA …

Bipartite Quantum Interactions: Entangling And Information Processing Abilities, Siddhartha Das

LSU Doctoral Dissertations

The aim of this thesis is to advance the theory behind quantum information processing tasks, by deriving fundamental limits on bipartite quantum interactions and dynamics. A bipartite quantum interaction corresponds to an underlying Hamiltonian that governs the physical transformation of a two-body open quantum system. Under such an interaction, the physical transformation of a bipartite quantum system is considered in the presence of a bath, which may be inaccessible to an observer. The goal is to determine entangling abilities of such arbitrary bipartite quantum interactions. Doing so provides fundamental limitations on information processing tasks, including entanglement distillation and secret key …

Economic Approaches And Market Structures For Temporal-Spatial Spectrum Sharing, Feixiang Zhang

LSU Doctoral Dissertations

In wireless communication systems, economic approaches can be applied to spectrum sharing and enhance spectrum utilization.

In this research, we develop a model where geographic information, including licensed areas of primary users (PUs) and locations of secondary users (SUs), plays an important role in the spectrum sharing system. We consider a multi-price policy and the pricing power of noncooperative PUs in multiple geographic areas. Meanwhile, the value assessment of a channel is price-related and the demand from the SUs is price-elastic. By applying an evolutionary procedure, we prove the existence and uniqueness of the optimal payoff for each PU selling …

Theoretical Studies Of Ultrafast Electron Dynamics In Atoms And Molecules Via High-Order Harmonic Generation, Paul Vincent Abanador

LSU Doctoral Dissertations

The interaction of atoms and molecules with strong laser pulses is of fundamental interest in physics and chemistry. Notably, the process known as high-order harmonic generation (HHG) refers to the production of extreme-ultraviolet (XUV) light, which occurs when an ensemble of atoms or molecules is subjected to a strong infrared laser field. Characterized by an attosecond time scale (1 as = 10^-18 s), the HHG process provides the capability for experimental measurements to capture the ultrafast motion of electrons in these target atoms and molecules. The underlying physical mechanism behind this process naturally leaves imprints in the properties of …

Genome-Wide Screening Identifies Genes And Biological Processes Implicated In Chemoresistance And Oncogene-Induced Apoptosis, Tengyu Ko

LSU Doctoral Dissertations

Anti-proliferative responses such as senescence and apoptosis are often used by normal cells to combat oncogenic insults and to prevent tumorigenesis. However, oncogenic mutations are frequently found in cancers, suggesting that additional mutations may occur to facilitate the bypass of these anti-proliferative responses. It is believed that some of these additional mutations may also contribute to the chemoresistance of cancers. This dissertation focused on identifying novel genes and biological processes implicated in chemoresistance and tumorigenesis.

Cisplatin-based chemotherapeutic regimens are frequently used for treatments of solid tumors. However, tumor cells may have inherent or acquired resistance to cisplatin, and the underlying …

Project Narrative: Examining The Interplay Of Experiences Of Participants In An After-School Writing Club, Courtney A. Brown

LSU Doctoral Dissertations

Writing is a vital part of literacy development. It affords the opportunity for the expression and analysis of comprehensive thought, while simultaneously being a modality for unique and creative communication. In order for productive dialogue about the study of writing to be engaged, the contemplation of its many dynamic parts occurring across a diversity of contexts must be considered in such a way that one writing strategy, process, product or environment is not privileged above another. Each constituent part of writing construction contributes meaningfully to the existing body of research for this field, and when carefully disaggregated can offer specific …

Exploring The Interdependence Of Trust And Communication In The Teacher-Principal Relationship, Jon Oliver Downs

LSU Doctoral Dissertations

This research explored teacher and principal perceptions of trust and communication in the teacher-principal relationship. Through in-depth interviews, research participants provided perceived characteristics needed for effective teachers, principals, and teacher-principal relationships, and pointed out characteristics detrimental to the effectiveness of the teacher-principal relationship. The research utilized past research in organizational communication, trust, and trust and communication within the teacher-principal relationship and other important components of effective teacher-principal relationships to provide a literary foundation for the study. The research identified perceptions of teachers and principals with respect to communication and trust in the teacher-principal relationship, and identified what priorities successful first-year …

Religion, Racism, And Ecological Stress Among African-American Families: A Qualitative Analysis Of Perceptions And Coping Strategies, Johnnie W. Jones

LSU Doctoral Dissertations

ABSTRACT

Americans do not reside in what many consider now a Post-Racial society. A remarkable number of researchers found that African Americans are more likely than any other racial group to experience racism, manifested by racist attitudes and practices, which negatively affect their physical, mental, and emotional wellbeing (health). Very importantly, numerous scholarly works have examined racism and Black women qualitatively. Unfortunately, less has been known about the personal processes and meaning-making mechanisms of Black married couples and African American males in terms of how they cope with racism, and ecological stress. To address this gap, this study uses qualitative …

Chemically Modified Cellulosic Materials As Multi-Functional Agents In Polymer Composites, Jinlong Zhang

LSU Doctoral Dissertations

Comparative flame retardancy of micro wood fiber plastic composites (WPCs) with fire retardants (1,2-bis(pentabromophenyl) ethane, metal hydroxides and nanoclay) was studied. The fire additives (1,2-bis(pentabromophenyl) ethane as well as magnesium hydroxide) obviously enhanced the fire retarding properties of WPCs. Especially, 1,2-bis(pentabromophenyl) ethane significantly reduced the total heat release as well as heat release rate. In addition, a synergistic effect of 1,2-bis(pentabromophenyl) and nanoclay was achieved for the enhanced fire retarding performance of WPCs.

A copolymer of cellulose nanocrystals (CNCs) and poly(N-vinylcaprolactam) (PVCL) (PVCL-g-CNCs) for use as thermally-responsive polymers with low critical solution temperatures (LCSTs) was synthesized via atom transfer radical …

Development, Validation, And Testing Of A Self-Determination Theory Instrument Called The Motivation To Prepare Healthy Foods Questionnaire, Ariana Delong Bailey

LSU Doctoral Dissertations

The objectives of these studies were to validate and confirm the structure of a previously developed questionnaire that measures the psychosocial constructs defined by the Self-Determination Theory (SDT) and then test this questionnaire in a nutrition education setting. The instrument, titled the Motivation to Prepare Healthy Foods Questionnaire (MPHFQ), included items that measured intrinsic motivation, perceived competence, relatedness, autonomy, and autonomy support. These studies evaluated the questionnaire’s validity and ability to measure changes in the SDT construct scores.

The MPHFQ is a previously developed and reliable instrument intended to measure adults’ intrinsic motivation and perceived competence to prepare healthy foods, …