Physical Sciences and Mathematics Commons^™

Patterns And Pathways Of Wetland Sedimentation And Landscape Change In Coastal Louisiana, Andrew William Tweel

LSU Doctoral Dissertations

Coastal Louisiana wetlands exist in a dynamic physical environment and retracted dramatically in the last century. Here I examine the spatial and temporal variability of this landscape with an emphasis on the interactions between anthropogenic landscape modifications and geological processes.

The Mississippi River watershed underwent drastic changes during the past 200 years, beginning with widespread land clearing and, later, large-scale reservoir construction. These modifications caused increases in suspended sediment concentrations, then sharp decreases, and have remained relatively stable since 1960. I show how changes in land area of the Mississippi River birdfoot delta reflect these fluctuations, and that they are …

Exploring Student Perseverance In Problem Solving, Angelique Renee (Treadway) Duncker

LSU Master's Theses

ABSTRACT Many high school Geometry students lack the perseverance required to complete complex and time-consuming problems. This project tests the hypothesis that if students were provided with a means of organizing their problem solving work they will be less apt to quit when faced with complex and time-consuming mathematical problems. This study involved students enrolled in 10th grade Geometry and 10th grade Honors Geometry in two similar high schools. After trying unsuccessfully to implement methods adapted from an engineering workshop, I designed a graphic organizer that was simple to use and acceptable to the students. Ultimately, I did not detect …

Spatial Structure And Dynamics Of The Plant Communities In A Pro-Grading River Delta : Wax Lake Delta, Atchafalaya Bay, Louisiana, Melissa Carle

LSU Doctoral Dissertations

River deltas are dynamic depositional environments that are controlled to varying degrees by coastal and fluvial forces. Plant communities in deltas respond to many of the same allogenic forces that shape delta geomorphology. This study examines the factors that influence plant community development, productivity, and species distributions in the Wax Lake delta, a young, actively pro-grading river delta in coastal Louisiana, USA. A species distribution map created using high-resolution 8-band WorldView-2 imagery was found to have an overall accuracy of 75 percent. Classification tree analysis suggested that most of the observed variation in plant species distributions within the delta can …

Evaluating The Effectiveness Of Response To Intervention In Ela And Math For Sixth, Seventh, And Eighth Grade Students, Shehla Khan

LSU Master's Theses

Abstract This study examined the combined effectiveness of Tier I and Tier II instruction in the context of a Response to Intervention framework with sixth, seventh and eighth grade students both in ELA and Math. The Tier I interventions emphasized topics from the Grade Level Expectations that the students were having difficulties grasping during regular classroom instruction. Tier II instruction mainly emphasized preparing students for the standardized iLEAP and LEAP tests. These students were then compared with a group of similar students who did not receive tiered instructions (control group). Students who participated in Tier I or Tier II instructions …

The Development Of Capillary Electrophoresis Assays To Study Enzyme Inhibition, Sherrisse Kelly Bryant

LSU Doctoral Dissertations

New methods for studying enzymes and enzyme inhibition using capillary electrophoresis (CE) were developed and applied. Because CE is a separation technique, spectral interference is minimized by separation of substrates, products, inhibitors, and sample matrix components. Two types of CE enzyme assays were explored in this dissertation research. The first assay was based on optically gated vacancy capillary electrophoresis (OGVCE) with laser-induced fluorescence detection (LIF). This approach involves periodic photobleaching of fluorescent substrates and products. The initial goal of the study was to develop an assay for adenosine deaminase (ADA). A fluorescent ADA substrate was synthesized; however, the substrate was …

Refining The Characterization Of Projective Graphs, Perry K. Iverson

LSU Doctoral Dissertations

Archdeacon showed that the class of graphs embeddable in the projective plane is characterized by a set of 35 excluded minors. Robertson, Seymour and Thomas in an unpublished result found the excluded minors for the class of k-connected graphs embeddable on the projective plane for k = 1,2,3. We give a short proof of that result and then determine the excluded minors for the class of internally 4-connected projective graphs. Hall showed that a 3-connected graph diff_x000B_erent from K5 is planar if and only if it has K3,3 as a minor. We provide two analogous results for projective graphs. For …

Analysis Of Protein Aggregates And Synthetic Nanoparticles Using Capillary Electrophoresis With Light Scattering And Fluorescence Detection, Suresh Chandra Regmi

LSU Doctoral Dissertations

The goal of the research presented in this dissertation is to develop capillary electrophoresis (CE) based analysis techniques for the characterization of individual particles including amyloid beta (Aâ) peptide aggregates and to apply these methods to study the aggregation of Aâ peptides. Protein self-assembly into ordered aggregates is a common and important process in normal biological function, but this process is also involved in several diseases. Amyloid beta peptide aggregation is linked to Alzheimer’s disease. Thioflavin T (ThT) has been used as a fluorescent probe for the detection of Aâ aggregation. Based on previous observations of false positive fluorescent signals …

Molecular Products From The Thermal Degradation Of Selected Tobacco Components: Lignin, Tyrosine, Glutamic Acid, And Modeling Of Lignin Pyrolysis Using Chemkin Combustion Suite, Joshua Kiprotich Kibet

LSU Doctoral Dissertations

This study explores the thermal decomposition behavior of selected tobacco components: lignin, tyrosine, and glutamic acid using the system for thermal diagnostic studies (STDS) in an in-line gas chromatography-mass spectrometer analytical technique. The pyrolysis conditions employed in this study were a flowing atmosphere of nitrogen and 4% O2 in nitrogen at a residence time of 0.2 seconds for a total pyrolysis time of 3 minutes. The results identified common relationships between the two modes of reaction atmospheres, as well as some differences. While some products were favored by an inert regime, some were favored under an oxidative regime. Oxidative pyrolysis …

Reef Fish Demographics On Louisiana Artificial Reefs : The Effects Of Reef Size On Biomass Distribution And Foraging Dynamics, Kirsten A. Simonsen

LSU Doctoral Dissertations

Understanding the role that habitat plays in the life history of reef-associated fishes is particularly significant given the dramatic increase in the number of artificial reefs deployed in coastal ecosystems over the past 50 years. In the Gulf of Mexico, the oil and gas industry has added a significant amount of structure to the Louisiana continental shelf, creating the largest de facto artificial reef deployment area in the world. Noting their usefulness as fish habitat, the Louisiana Artificial Reef Program was established to convert decommissioned platforms into artificial reefs. However, very little quantitative information exists on how these habitats affect …

Synthetic Efforts Toward The Eastern Hemisphere Of Theonellamide C, Douglas D. Wong

LSU Doctoral Dissertations

The theonellamides (TNMs) A-F are bicyclic dodecapeptides isolated from marine sponges of the genus Theonella and were shown to display potent antifungal activity. Despite considerable synthetic effort to produce TNM F by the Shioiri group in the early 1990s, a total synthesis of a TNM has yet to be reported. This dissertation describes our efforts toward some of the required amino acid residues of TNM C and the eastern hemisphere. The production of erythro-β-hydroxyasparagine (eHyAsn) followed the synthesis of threo-β-HyAsn by Boger and co-workers, utilizing a key Sharpless aminohydroxylation reaction. The eHyAsn building block, Boc-eHyAsn(OTBS)-OH, was coupled with HCl.Phe.OMe using …

Surface Studies Of Organic Thin Films Using Scanning Probe Microscopy And Nanofabrication, Venetia Denae Lyles

LSU Doctoral Dissertations

Porphyrins and metalloporphyrins have unique chemical and electronic properties and thus provide useful model structures for nanoscale studies of the role of chemical structure for electronic properties. Porphyrins have been proposed as viable materials for molecular-based information-storage devices, gas sensors, photovoltaic cells, organic light-emitting diodes and molecular wires. The function and efficiency of porphyrins in devices is largely attributable to molecular architecture and how the molecules are self-organized. Modifications of the porphyrin macrocycle, peripheral groups or bound metal ions can generate a range of electrical, photoelectrical or magnetic properties. The conductive properties are greatly influenced at the molecular level by …

Investigations Into Alkene Hydration And Alkene Oxidation Catalysis, William Schreiter

LSU Doctoral Dissertations

Bimetallic Ni complexes Ni21M and Ni21R and monometallic transition metal complexes were investigated as possible alkene hydration catalysts under a multitude of different reaction conditions. All attempts at performing this catalytic reaction failed to give any alcohol products. Catalytic screening experiments were conducted using a mixture of racemic-et,ph-P4 and meso-et,ph-P4, 1M and 1R, and various transition metals. These experiments gave several different products including 1-phenylethanol from styrene. During the course of the hydration experiments, an aldehyde product was identified from experiments conducted with the bimetallic complexes in air. Experiments have shown that the aldehyde is produced from the oxidative cleavage …

On Identifying Critical Nuggets Of Information During Classification Task, David Sathiaraj

LSU Doctoral Dissertations

In large databases, there may exist critical nuggets - small collections of records or instances that contain domain-specific important information. This information can be used for future decision making such as labeling of critical, unlabeled data records and improving classification results by reducing false positive and false negative errors. In recent years, data mining efforts have focussed on pattern and outlier detection methods. However, not much effort has been dedicated to finding critical nuggets within a data set. This work introduces the idea of critical nuggets, proposes an innovative domain-independent method to measure criticality, suggests a heuristic to reduce the …

Synthesis, Characterization And Biological Studies Of Carboranyl-Porphyrin Bioconjugates For Treatment Of Brain Tumors, Naga Venkata Satya Dinesh Kumar Bhupathiraju

LSU Doctoral Dissertations

Chapter 1 gives a brief introduction to brain tumors, approaches to deliver drug across the blood brain barrier (BBB), boron neutron capture therapy (BNCT) for brain tumors, application of carboranyl derivatives in attempt to treat brain tumors using BNCT. Chapter 2 involves synthesis, characterization and toxicity studies (In vitro and In vivo) of high boron containing pegylated cobaltabisdicarbollide porphyrin for treatment of brain tumors using BNCT. To improve the selectivity towards brain tumors we attempted conjugate several peptides to this non-toxic pegylated cobaltabiscabollide porphyrin. In vivo studies were conducted in collaboration with Dr. David G. Baker at LSU veterinary Medicine. …

Toward Digitizing The Human Experience : A New Resource For Natural Language Processing, Jerry Scott Weltman

LSU Doctoral Dissertations

A long-standing goal of Artificial Intelligence is to program computers that understand natural language. A basic obstacle is that computers lack the common sense that even small children acquire simply by experiencing life, and no one has devised a way to program this experience into a computer. This dissertation presents a methodology and proof-of-concept software system that enables non-experts, with some training, to create simple experiences. For the purposes of this dissertation, an experience is a series of time-ordered comic frames, annotated with the changing intentional and physical states of the characters and objects in each frame. Each frame represents …

Laser Ablation Sample Transfer For Mass Spectrometry, Sung-Gun Park

LSU Doctoral Dissertations

In this research, a new ambient sampling technique for mass spectrometry was developed that uses an infrared laser to ablate materials under ambient conditions that are captured in a solvent or on a surface. An infrared optical parametric oscillator (OPO) laser system at 3 μm wavelength was focused onto samples for ablation at atmospheric pressure. The ablated materials were transferred to a solvent or surface. For off-line electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) analysis, the ablated material was captured in a static solvent droplet that was deposited on a MALDI target or flow-injected into a nanoelectrospray source. The …

Single-Crystal Metal Oxides And Supported Metal Nanoclusters As Model Catalyst Sytems, Matthew C. Patterson

LSU Doctoral Dissertations

We have investigated the morphology and electronic structure of two basic classes of systems: metal oxide surfaces that catalyze the formation of environmentally persistent free radicals (EPFRs) from aromatic precursors, and Au and Cu nanoparticles that may be suitable catalysts for the catalytic oxidation of CO or hydrogenation of CO2. First, we examine the adsorption behavior of phenol on rutile TiO2(110) and ultrathin films of alumina prepared on a NiAl(110) substrate. Electron paramagnetic resonance studies show that exposure of both γ-alumina and titania powder to phenol at 250°C results in the formation of persistent phenoxyl radicals. EELS studies of phenol …

Oligohaline Wetland Response And Recovery Following Storm-Driven Saltwater Intrusion In Coastal Louisiana, Whitney Marie Kiehn

LSU Doctoral Dissertations

Coastal ecosystems occupy an interface between land and ocean, making them vulnerable to a variety of natural and anthropogenic disturbances. Large, episodic disturbances (mega-disturbances) cause immediate and long-lasting changes to coastal wetland plant communities and soils by changing the environmental conditions in which they exist. Here I examined the impacts of storm-induced saltwater intrusion and post-intrusion conditions on the structure and growth of an oligohaline wetland plant community, and on wetland soil biogeochemistry and conditions during and after saltwater intrusion. In the greenhouse, a six-week saltwater intrusion reduced canopy cover and species richness. Once intrusion stress was alleviated, plant community …

A Study Of The Temporal And Spatial Distribution Of Ichthyoplankton And Post-Larval Penaeids Recruiting Into A Louisiana Tidal Pass, Matthew John Kupchik

LSU Doctoral Dissertations

This dissertation attempts to better understand astronomical, meteorological, and oceanographic forcing of offshore-spawned, estuarine-dependent species from continental shelf to estuarine waters through tidal passes. The vertical distribution of zoo-/ichthyoplankton within the inner continental shelf from the Louisiana Offshore Oil Platform monitoring project (1978-1995) provided an important offshore end member for the estuarine recruitment study, and is potentially useful in predicting vulnerabilities to past and future oil spills. The role that atmospheric cold front passages may have on densities and movement of zoo-/ichthyoplankton recruiting through the Bayou Tartellan tidal pass, Louisiana, were analyzed using a Generalized Additive Model. The pre-frontal phase, …

Earth Occultation Imaging Of The Low Energy Gamma-Ray Sky With The Fermi/Gamma-Ray Burst Monitor, James Craig Rodi

LSU Doctoral Dissertations

The hard X-ray/soft gamma-ray sky is highly variable as source intensities can vary on timescales from fractions of a second to years. The type of sources emitting at these energies often include compact objects such as white dwarfs, neutron stars, and black holes interacting with the surrounding environment, which enables the study of the properties and characteristics of these exotic objects. Because the interactions with the environment is often through accretion, most of the emission is in X-rays and gamma-rays Frank et al. 1992 making this energy range critical to understanding the relevant physical processes and mechanisms. Hard X-ray/soft gamma-ray …

Complexity-Driven Properties Of The Intermetallic Compounds Gd₁₁₇Co₅₆Sn₁₁₂ And Ln₃₀Ru₄Sn₃₁ (Ln = Gd And Tb), Devin Charles Schmitt

LSU Doctoral Dissertations

Understanding the relationships between the structure of materials and their properties in extended solid systems is a necessity when intuitively designing functional materials. One of the most fundamental properties of a material is its ability to transport heat, which is linked to the lattice complexity of the material. Here, the single crystalline materials Gd117Co56Sn112 and Tb30Ru4Sn31 are grown to study the pronounced effect of a complexity-driven reduction of lattice thermal conductivity. The transport and magnetic properties of Gd117Co56Sn112 and Ln30Ru4Sn31 (Ln = Gd and Tb) are also presented and related to other systems. Tb30Ru4Sn31 is found to be a large …

Finite Element Methods For Fourth Order Variational Inequalities, Yi Zhang

LSU Doctoral Dissertations

In this work we study finite element methods for fourth order variational inequalities. We begin with two model problems that lead to fourth order obstacle problems and a brief survey of finite element methods for these problems. Then we review the fundamental results including Sobolev spaces, existence and uniqueness results of variational inequalities, regularity results for biharmonic problems and fourth order obstacle problems, and finite element methods for the biharmonic problem. In Chapter 2 we also include three types of enriching operators which are useful in the convergence analysis. In Chapter 3 we study finite element methods for the displacement …

The Ring Theory And The Representation Theory Of Quantum Schubert Cells, Joel Benjamin Geiger

LSU Doctoral Dissertations

In recent years the quantum Schubert cell algebras, introduced by Lusztig and De Concini--Kac, and Procesi, have garnered much interest as this versatile class of objects are furtive testing grounds for noncommutative algebraic geometry. We unify the two main approaches to analyzing the structure of the torus-invariant prime spectra of quantum Schubert cell algebras, a ring theoretic one via Cauchon's deleting derivations and a representation theoretic characterization of Yakimov via Demazure modules. As a result one can combine the strengths of the two approaches. In unifying the theories, we resolve two questions of Cauchon and Mériaux, one of which involves …

Structural And Synthesis Studies Of The Pro¹⁴³ Region Skp1 In Dictyostelium Discoideum, Chamini V. Karunaratne

LSU Doctoral Dissertations

In Skp1 of Dictyostelium discoideum (Dd), Pro143 is located at the N-terminus of an α-helix with four consecutive Glu residues immediately following Pro. Preceeding Pro143 is a segment of random coil. The proline residue undergoes post-translational modifications: hydroxylation and glycosylation. A cytoplasmic prolyl hydroxylase (P4H1) delivers a hydroxyl group to Pro143 and N-acetylglucosamine transferase 1 (Gnt1) transfers GlcNAc from UDP to Hyp143 of Skp1. The installation of the first GlcNAc residue in Skp1 in Dictyostelium is important for the organism to differentiate into a fruiting body to disperse spores. We describe herein some structural and synthesis studies of the Pro143 …

Experimental And Computational Studies Of Environmentally Persistent Free Radicals (Epfrs) Formation, Lucy W. Kiruri

LSU Doctoral Dissertations

The first part of the thesis investigates the use of theoretical quantum calculations for the study of EPFRs as the initial and fundamental step in the formation of polychlorinated dibenzo-p-dioxin and dibenzofuran. The computational model comprised of density functionals (B3LYP, PBE1PBE, and M06) and two types of basis set namely: LANL2DZ for all atoms and GEN (LANL2DZ for metals and aug-cc-pVDZ for non-metals). Full mechanisms of EPFRs formation over (CuO)1-8, and aluminum oxide clusters were studied. The most stable intermediates and products have been determined and compared to available experimental data. In case of (CuO)1-8 clusters, the small clusters are …

Incorporating Science-Based Approaches Into The Rapid Assessment Of Wetlands And Streams : Validation, Restoration Trajectory, And Method Development, Jacob Franklin Berkowitz

LSU Doctoral Dissertations

Human alterations within wetlands and streams have resulted in a decrease in ecological functions and associated benefits to society. The scientific literature highlights the functional benefits provided by ecosystems including flood protection, nutrient cycling, and habitat maintenance. Additionally, legislation and regulatory policy require mitigation and restoration as compensation for declines in ecological functions. As a result, the need for practical, repeatable, and technically sound ecosystem assessment methods remains essential to natural resource management. However, few studies determine the validity of rapid assessment approaches by applying quantitative parameters, especially with respect to biogeochemical functions. We assessed biogeochemical functions applied to restored …

Amplifying Conjugated Polymers For Fluorescent Chemosensing, Deepa Pangeni

LSU Doctoral Dissertations

Chemo- and biosensors based on fluorescent conjugated polymers benefit from greater detection sensitivity due to amplification of the electronic perturbations produced by analyte binding. This amplification stems from the exciton-transporting properties of conjugated polymers. In the conventional sensor design paradigm, excitons migrate from the bulk of the polymer to the analyte binding sites which can be either fluorescence quenching sites (turn-off sensors) or lower energy fluorophores (turn-on sensors). In this dissertation, we proposed an alternative design paradigm when analyte binding creates a higher energy gap site in the polymer backbone. In the case of isolated polymer chains in dilute solution, …

Microfluidics For The Analysis Of Integral Membrane Proteins: A Top-Down Approach, Katrina Nychole Battle

LSU Doctoral Dissertations

The development of fully automated and high-throughput systems for proteomics is now in demand because of the need to generate new protein-based disease biomarkers. Unfortunately, it is difficult to identify protein biomarkers that are low abundant when in the presence of highly abundant proteins, especially in complex biological samples like serum, cell lysates, and other biological fluids. Membrane proteins, which are in many cases of low abundance compared to cytosolic proteins, have various functions and can provide insight into the state of disease and serve as targets for new drugs making them attractive biomarker candidates. Traditionally, proteins are identified through …

Skein Theory And Topological Quantum Field Theory, Xuanting Cai

LSU Doctoral Dissertations

Skein modules arise naturally when mathematicians try to generalize the Jones polynomial of knots. In the first part of this work, we study properties of skein modules. The Temperley-Lieb algebra and some of its generalizations are skein modules. We construct a bases for these skein modules. With this basis, we are able to compute some gram determinants of bilinear forms on these skein modules. Also we use this basis to prove that the Mahler measures of colored Jones polynomial of a sequence of knots converges to the Mahler measure of some two variable polynomial. The topological quantum field theory constructed …

Design, Synthesis, And Characterization Of Porphyrin Derivatives For Biological Applications, Raja Gabadage Waruna Eranga Jinadasa

LSU Doctoral Dissertations

Chapter 1 of this Dissertation presents a brief introduction to the basic properties of porphyrins and their derivatives (hydroporphyrins), their abundance and functions in the nature, and their applications in photodynamic therapy. Chapter 2 reports the synthesis, characterization, conformational analysis and cellular studies of novel mono conjugated regioisomers of chlorin e₆ derivatives that are promising photosensitizers for photodynamic therapy. All three regioisomers were synthesized from pheophytin a, which was extracted from the alga Spirulina pacifica. In vitro investigations using human carcinoma HEp2 cells show that the 15²-lysyl regioisomers accumulate the most within cells, and the most phototoxic …