Digital Commons Network^™

Insights Into 5-Lipoxygenase Active Site And Catalysis, Sunayana Mitra

LSU Doctoral Dissertations

Leukotrienes are potent immune-modulatory compounds involved in the inflammatory response. 5-Lipoxygenase (5-LOX) is the enzyme that catalyzes the production of Leukotriene A4 (LTA4), which is further metabolized to pro- and anti-inflammatory compounds derived from the substrate Arachidonic Acid (AA), a polyunsaturated fatty acid. The crystal structure of a stabilized form of 5-LOX has been recently reported (Gilbert, Bartlett et al. 2011). However, the structure does not reveal the mode of substrate entry or recognition. The first step in the enzymatic reaction involves the removal of a hydrogen from the central carbon of a pentadiene present in the substrate. It is …

Anisotropic Spacetimes And Black Hole Interiors In Loop Quantum Gravity, Anton Joe

LSU Doctoral Dissertations

This thesis deals with understanding quantum gravitational effects in those anisotropic spacetimes which serve as black hole interiors. Two types of spacetime are investigated. Kantowski-Sachs spacetime and Bianchi-III LRS spacetime. The former, in vacuum, is the interor spacetime for Schwarzschild black holes. The latter is the interior for higher genus black holes. These spacetimes are studied in the context of loop quantum cosmology. Using effective dynamics of loop quantum cosmology, the behavior of expansion and shear scalars in different proposed quantizations of the Kantowski-Sachs spacetime with matter is investigated. It is found that out of the various proposed choices, there …

Nuclear Structure Of 26si And 32cl For Astrophysics, Liudmyla Afanasieva

LSU Doctoral Dissertations

We studied the nuclear structure of two isotopes, 26Si and 32Cl, important for understanding stellar explosions like novae and Type I X-ray bursts. The 31S(p,γ)32Cl reaction rate influences the enrichment of sulfur observed in some nova ejecta, but the uncertainty in the rate spans as much as an order of magnitude and arises from uncertainties in the properties of resonances corresponding to excited states in 32Cl. We populated states in 32Cl via the 10B(24Mg,2n)32Cl reaction using the Argonne Tandem-Linac Accelerator System (ATLAS), with a 75 MeV beam of 24Mg bombarding a 200 μg/cm2 10B target. Gamma rays emitted from recoiling …

Planktonic Influence On The Toxicity Of Hewafs (High-Energy Water Attenuated Fractions), Erin Elizabeth Saal

LSU Master's Theses

The Deep Water Horizon oilrig explosion led to the release of 6.8 ± 1.7 x 108 kg or 4.9 million barrels of petroleum hydrocarbons into the Gulf of Mexico. The spill persisted from the end of April to mid July 2010 affecting a significant portion of the Gulf coast. The effects of this spill are being studied in labs across the country, and this thesis investigated high-energy water accommodated fractions (HEWAFs) as a potential tool for use in this effort. Water accommodated fractions (WAFs) are mediums containing only the fraction of petroleum that remains in aqueous phase after a mixing …

Interpretation Of Geochemical Signatures From Modern Carbonate Springs To The Rock Record, Benjamin Maas

LSU Doctoral Dissertations

Despite the importance of carbonate aquifers as reservoirs of oil, of water, and of carbon dioxide, questions remain about the diagenetic processes that enhance porosity and permeability. Some of the questions are: 1) what are the water-rock interactions that control the geochemistry of spring waters; 2) are the geochemical signatures of saline-fresh water mixing zones preserved in the carbonate rock record; and 3) how much carbon dioxide outgases along spring runs? To address these questions, two field sites, one in Oklahoma (the site of an active saline-fresh water mixing zone) and the other in Colorado, the location of a former …

Anthropogenic Impacts On Soil Microbial Processes In Coastal Wetlands: Nutrient Loading And Rising Co2 Levels, Havalend Ellen Steinmuller

LSU Master's Theses

Atmospheric carbon dioxide (CO2) levels and global eutrophication are anthropogenic stressors impacting the environment of specific interest in wetland systems. Wetlands occupy a critical interface between terrestrial and aquatic environments. Fertilizer use for agriculture and treated wastewater disposal has increased nutrient loading to wetlands. Conflicting results on impacts of nitrogen loading to coastal wetland soils have been reported, though most studies have investigated short-term impacts of nutrient loading, not long-term integrated impacts. I investigated an 11-year period of nutrient loading on soils in an oligohaline coastal wetland. Nitrogen treatments of 0, 50, 200, and 1200 kg ha-1 yr-1 were paired …

Habitat Preferences Of Adult Spotted Seatrout, Cynoscion Nebulosus, In Lake Pontchartrain, Louisiana, Noelle Marie Bramer

LSU Master's Theses

Spotted seatrout (Cynoscion nebulosus) are a highly sought after sportfish, making up over 90% of the recreational fishery in Louisiana. As a significant portion of every life history stage is spent within its natal estuary, it is an ideal bio-indicator of estuarine health. As one of the largest estuaries in Louisiana, Lake Pontchartrain represents one such supporting ecosystem. From November 2012 to April 2014 acoustic tagging of individual fish, a lake-wide receiver array, and ArcGIS mapping software were utilized to determine the spatial distribution of spotted seatrout within the lake. Receivers were placed in representative locations including man-made and natural …

#Becoming: Emergent Identity Of College Students In The Digital Age Examined Through Complexivist Epistemologies, Paul William Eaton

LSU Doctoral Dissertations

This dissertation explores the possibilities and limitations of conducting research on college student identity in the digital age. Utilizing philosophical theories from complexity theory, post-qualitative research, and new materialisms, I interrogate, question, disrupt, and challenge current theories and models of college student identity, largely developed from a positivist, modernist, empiricist perspective. Conducting research on college student identity in the twenty-first century may benefit from discarding the old ‘developmental’ language of the twentieth century, replacing this discourse and understanding with a language drawn from complexity theory. In this regard, I believe educators, researchers, and practitioners should begin talking about identity emergence …

Magnetic Susceptibility Of North American Ordovician Epicontinental Seas: Spatial Variability And Sandbian-Katian Boundary Correlation, Thomas J. Schramm

LSU Doctoral Dissertations

Magnetic susceptibility (χ) has gained increased usage as a stratigraphic correlation tool. This project evaluates the utility of a χ correlation tool, including its shortcomings, and attempts its integration with other datasets. The Upper Ordovician of eastern North America represent the stratigraphic interval in which these experiments were conducted. 4566 samples were collected for the purposes of this study, and χ was measured on 3345 of the samples. This project includes three major facets, 1) the spatial variability of χ, 2) correlation of Sandbian-Katian boundary interval strata in eastern North America using χ, and 3) utility of χ for interpreting …

L'Essentiel Ou Lagniappe: The Ideology Of French Revitalization In Louisiana, Albert Camp

LSU Doctoral Dissertations

Louisiana’s French revitalization movement has received millions of dollars in taxpayer funding through its various initiatives such as music and cultural festivals, public school French immersion programs, and academic exchange programs, among others. Over forty years ago, the state of Louisiana created CODOFIL, a government agency dedicated to the promotion of Francophone language and culture in Louisiana, yet the number of Francophones in the state has continued to decline at an alarming rate according to the most reliable data available. My study investigates the ideology and demographics of those involved in French education programs in Louisiana’s public schools. Who decides …

Spectrum Allocation In Networks With Finite Sources And Data-Driven Characterization Of Users' Stochastic Dynamics, Ahsan-Abbas Ali

LSU Doctoral Dissertations

During emergency situations, the public safety communication systems (PSCSs) get overloaded with high traffic loads. Note that these PSCSs are finite source networks. The goal of our study is to propose techniques for an efficient allocation of spectrum in finite source networks that can help alleviate the overloading of PSCSs. In a PSCS, there are two system segments, one for the system-access control and the other for communications, each having dedicated frequency channels. The first part of our research, consisting of three projects, is based on modeling and analysis of finite source systems for optimal spectrum allocation, for both access-control …

Fish Biomass And Community Structure Around Standing And Toppled Oil And Gas Platforms In The Northern Gulf Of Mexico Using Hydroacoustic And Video Surveys, Emily Marissa Reynolds

LSU Master's Theses

There has been relatively little study of the efficacy of decommissioned oil and gas platforms as artificial reef habitats for fish assemblages in the northern Gulf of Mexico (GOM). A variety of fish species have been reported on these structures, but the species biomass distribution and community structure has not been studied thoroughly. Hydroacoustic and video surveys were conducted quarterly from June 2013 to June 2014 at three standing and two toppled oil and gas platforms located approximately 130 km off the coast of Louisiana at 90 m depth; to gain information about the spatial biomass distribution and community structure …

Synthesis With Hypergraphs, Christopher Thomas Alvin

LSU Doctoral Dissertations

Many problems related to synthesis with intelligent tutoring may be phrased as program synthesis problems using AI-style search and formal reasoning techniques. The _x000C_first two results in this dissertation focus on problem synthesis as an aspect of intelligent tutoring systems applied to STEM-based education frameworks, specifically high school geometry. Given a geometric _x000C_figure as input, our technique constructs a hypergraph representing logical deduction of facts, and then traverses the hypergraph to synthesize problems and their corresponding solutions. Using similar techniques, our third result is focused on exhaustive synthesis of molecules. This synthesis process involves bonding sets of basic, molecular `fragments' …

Applications Of Large Eddy Simulation To Study Flow And Sediment Transport In Open Channel Flows, Getnet Baynesagne Agegnehu

LSU Doctoral Dissertations

The motivation of this study is to extend applications of Large Eddy Simulation (LES) for typical open channel flows to elucidate the time dependent three dimensional flow and sediment transport features which are usually difficult to measure in experiments. Detailed investigations are performed on the unsteady features and, in particular, turbulent structures of the flow to demonstrate the great potential of eddy resolving methods. The instantaneous flow and sediment transport fields are investigated together with the existence of coherent structures. These structures together with ejection events (u' < 0, w' > 0), are responsible for the vertical and lateral transport of suspended sediment from …

Examining The Supervisor-Similarity And Work-Family Conflict Relationship: Is Family-Supportive Supervision A Mediator?, Chela M. White-Ramsey

LSU Doctoral Dissertations

To say that interest in work-family conflict has increased is an understatement. With the number of dual-earner households increasing, the diversification of the workforce, and women quickly moving into industries that were once primarily male-dominated, the work-family literature is filled with various intonations of the concept. Drawing on insights from social identity and self-categorization theories, this dissertation examined how supervisor-subordinate demographic similarity might relate to the provision of family-supportive supervision and work-family conflict. 102 members of a professional organization dedicated to women who work in technology were surveyed to evaluate whether or not supervisor-subordinate racial and gender similarity would predict …

Potential For Geothermal Energy In Northern Louisiana: Analysis Of The Subsurface Environment In Union And Morehouse Parishes, Tessa Shizuko Hermes

LSU Master's Theses

Efforts to mitigate greenhouse gas emissions and reduce dependence on fossil fuels have led to renewed focus on the exploration and development of alternative energy production. One such option is hydrothermal binary geothermal energy production from geothermal reservoirs with temperatures of at least 100 °C at depths no greater than 5 km. In the U.S., such systems have the potential to provide 5,400 % of 2013 total U.S. energy consumption. This study evaluates the potential for geothermal energy systems implementation in Morehouse and Union Parishes, Louisiana, by using publicly available bottom hole temperature (BHT), mud weight (MW), logged formation top …

Evaluating The Interspersal Procedure Using Free Access To A Competing Reinforcer, Catherine Rose Lark

LSU Master's Theses

Previous research has shown that interspersing additional easy problems among difficult target problems increases target problem fluency and student preference for an assignment. Nonetheless, there have been some contradictory findings concerning the efficacy of the interspersal procedure, so more research is needed to determine whether teachers should use this procedure for academic assignments. The current study attempted to replicate and extend the research on this procedure by using access to a competing reinforcer (an iPad) and a homework analogue. Fourth-grade students were given access to an iPad, but were told to work first for 10 minutes each on a control …

Dwelling Poetically, Proceeding Orphically: The Platonic Tradition And The Heideggerian Humanism Of Ernesto Grassi, Geoffrey Alexander Leeves Bain

LSU Doctoral Dissertations

Martin Heidegger exerted an immense influence over twentieth century thought by providing profound insights into the nature of Being as well as scathing social critiques, focused on the destructive force of late modern technological reductionism. As part of Heidegger’s project, he elaborated upon a sophisticated history of Being in which two great monsters of Platonism and Humanism are cast as Antichrist and False Prophet. Subsequently, however, his own student Ernesto Grassi argued that Renaissance Humanism was not a stepping stone towards subjectivism and technological thinking, but rather stood in conformity with the fundamental essence of Heidegger’s own project. This study …

Optimized Aperiodic Multilayer Structures For Absorbers And Thermal Emitters, Christopher H. Granier

LSU Doctoral Dissertations

In this dissertation, we begin with a brief introduction to nanophotonics. In particular, we will focus on the theory of computational electricity and magnetism, specifically, the method used for this research, the transfer-matrix method. We will also provide discussions of the principles which motivate the analysis of the multilayer structures: Planck's blackbody distribution, Kirchoff's law, and thermodynamics. Finally, we will provide a brief discussion of computer-based optimization algorithms, specifically NLOPT (a library which provides computational packages for nonlinear optimization) and genetic algorithms. This background information is necessary to understand discussions which occur in later chapters.

Chapter 2 will discuss multilayer …

The Agronomic Use And Application Of Canopy Reflectance Within The Visible And Near-Infrared Wavebands And Its Relation With Nitrogen Fertilization In Energy Cane Production In Louisiana, Saoli Chanda

LSU Doctoral Dissertations

Spectral vegetation index-based models that are used to estimate yield potential are commonly developed from the relationship between early-season crop canopy reflectance readings and actual yield obtained at harvest. Plant population stand can influence cane yield potential and nutrient requirement. This study was conducted at LSU AgCenter Sugar Research Station in St. Gabriel, LA to evaluate (1) the relation between estimated early season biomass yield and the spectral vegetation indices acquired at the same time, (2) nitrogen (N) response pattern between early-season biomass production and yield at harvest, and (3) the relationship between coefficient of variation (CV) among normalized difference …

Attosecond Transient Absorption In Gases And High Harmonic Generation In Solids, Mengxi Wu

LSU Doctoral Dissertations

We present a theoretical study of attosecond transient absorption in gases and high harmonic generation in solids. In this thesis, different features in the attosecond transient absorption laser-dressed spectrum are studied, including features near bright (dipole allowed) atomic states and features that appear approximately one or two laser photons away from the bright states due to the laser-induced coupling to dark (non-dipole allowed) states. The calculations are carried out using both numerical and analytic solutions to the time-dependent Schr\"odinger equation (TDSE). From these solutions, several models of time-dependent absorption and electron dynamics at the femtosecond time scale are presented. We …

Peer Coaching Effects On Targeted Teaching Behaviors And Teacher Self-Efficacy In An Early Field Experience, Deanna Kay Rice

LSU Doctoral Dissertations

Abstract This study examined the effect of peer coaching on the development of effective teaching behaviors and teacher self-efficacy of education students in an early field experience. The convenience sample (N = 99) included undergraduate students enrolled in a required foundational course in special education at a large public university in the southern United States. Training methods included online video instruction on targeted effective and ineffective teaching behaviors. The effective behaviors included (a) established student learning objective prior to beginning a lesson, (b) explained and/or modeled how pupil can discover answer or solve a problem, (c) checked for understanding by …

Effect Of The Herbicide Atrazine On Phytoplankton, Water Quality, And Ecosystem Functions In Louisiana Estuaries, Alexis Victoria Starr

LSU Master's Theses

Pesticides are used primarily for agricultural purposes in the US and while these chemicals provide many benefits, the inherent toxicity of the compounds pose a substantial risk to the environment. These chemicals may enter water bodies in areas with a high proportion of agricultural land use through surface run off, ground water discharge, and erosion, and negatively impact non-target aquatic organisms. As a result, Louisiana’s estuaries may be vulnerable to a variety of compounds, including the herbicide atrazine. Atrazine is used extensively throughout the Midwest and has been known to enter the Mississippi River through surface runoff and ground water …

The Effects Of Tropical Storms And Hurricanes On Phytoplankton And Nutrient Concentrations In Wetland-Estuary Transition Zones Along The Gulf Coast, Tiffany Chantelle Johnson

LSU Master's Theses

Two consecutive storms made landfall along the Northern Gulf of Mexico on June and August 2012 (Tropical Storm Debby, 06/26/2012; Isaac, 08/28/2012, Category (Cat) 1 Saffir-Simpson Hurricane Scale). Each storm passed within 48 to 273 km of one of seven wetland-estuary transition zone sampling sites, and indirect storm effects associated with changes in freshwater discharge and an inflow of inorganic nutrients were observed at five of the seven sites. To assess the impacts of the 2012 hurricanes on hydrology, nutrient concentrations, and phytoplankton concentrations at transition zones along the Gulf Coast, a within-sites analysis along with a seasonal analysis were …

Magnetic Resonance Elastography Of The Brain Using An Ergonomic Driver: Assessment Of Scan-Rescan Reproducibility, Hatim Chafi

LSU Master's Theses

Magnetic resonance elastography (MRE) allows the visualization of displacement patterns from induced harmonic mechanical waves propagating in tissue. Strain and mechanical properties can be computed from these displacement patterns. Mechanical properties of tissue are affected by various disease processes. MRE has shown brain tumor to differ in stiffness in comparison to normal tissue. MRE is currently being offered as an upgrade on most conventional MRI scanners. However, the actuator supplied by vendors is a drum driver designed primarily for hepatic MRE scan. The goals of the project was to design and build an ergonomic flexible driver for use in MRE …

Game Theoretic Analyses Of The United States-Canada Softwood Lumber Trade, Rajan Parajuli

LSU Doctoral Dissertations

The ongoing softwood lumber trade dispute between the United States (U.S.) and Canada is one of the most contentious and largest bilateral trade battles over the recent decades. The bilateral trade debate is mostly because of the different forestland ownership systems in the U.S. and Canada, and the alleged timber subsidies by provincial governments to Canadian lumber producers. The Softwood Lumber Agreement (SLA) 2006 between the U.S. and Canada is the latest transitory solution of this dispute, entailing Canada to impose mandatory export charges on its lumber shipments to the U.S. In order to understand this trade dispute from a …

Examination Of The Effects Of The Homework, Organization, And Planning Skills (Hops) Intervention On Undergraduate Students, Ashley E. Bordelon

LSU Master's Theses

Homework, organization, and time-management skills are often a source of stress for undergraduate students. The type of homework given, self-management skills, and planning skill level combine to contribute to student success in school. Previous research has shown that the Homework, Organization, and Planning Skills (HOPS) program has been successful with teaching these skills; however, research has focused on younger students. The purpose of the current study was to determine if the HOPS program was suitable for undergraduate students, based on pretest, posttest, and follow-up scores on the Learning and Study Strategies Inventory- Second Edition (LASSI) using a randomized waitlist control …

Left-Orderability, Cyclic Branched Covers And Representations Of The Knot Group, Ying Hu

LSU Doctoral Dissertations

A group G is called left-orderable if one can find a total order on G, which is preserved under left multiplication. In this paper we first give a sufficient condition for the fundamental group of the nth cyclic branched cover of the three sphere over a prime knot K to be left-orderable, in terms of representations of the knot group. Then we make use of this criterion to study the left-orderability of fundamental groups of cyclic branched covers over two-bridge knots and satellite knots.

Pytracks: A Tool For Visualizing Fish Movement Tracks On Different Scales, Ross Fossum

LSU Master's Theses

A fundamental problem in conservation biology and fisheries management is the ability to make educated decisions based on the data collected. Fish populations and their spatial distributions need to be represented accurately for conversation efforts and management decisions. Methods such as modeling, surveying, and tracking can all be used to collect data on a particular fishery. To include the movement patterns in conservation and management, one needs to work with and process fish tracking data or data exported from fish movement simulation models. This data can often be difficult to process. This topic is becoming increasingly popular as technology to …

A Study Of Resiliency In New Orleans Neighborhoods Ten Years After Hurricane Katrina, Paul Ramnauth Algu

LSU Master's Theses

Hurricane Katrina made landfall on August 29, 2005, flooding over eighty percent of the Greater New Orleans area and causing a mass exodus of the local population. Statistical analysis was used to quantify recovery at a neighborhood level and answer the following questions: What is the recovery rate of New Orleans neighborhoods ten years after Hurricane Katrina? What factors account for variation in recovery rates among neighborhoods? Six neighborhoods in Orleans Parish were selected for further study based on their unique geographical and recovery metrics. Recovery rates among the seventy-two neighborhoods were based on a comparison of United States Postal …