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Articles 2551 - 2580 of 3417

Full-Text Articles in Physical Sciences and Mathematics

Two Post-Harvest Treatments For The Reduction Of Vibrio Vulnificus And Vibrio Parahaemolyticus In Eastern Oysters (Crassostrea Virginica), Kevin Patrick Melody Jan 2008

Two Post-Harvest Treatments For The Reduction Of Vibrio Vulnificus And Vibrio Parahaemolyticus In Eastern Oysters (Crassostrea Virginica), Kevin Patrick Melody

LSU Master's Theses

Vibrio vulnificus and V. parahaemolyticus are naturally occurring estuarine bacteria and the leading causes of seafood-borne illness in the United States. Multiple outbreaks due to raw oyster consumption in the last decade has lead to much research to remediate these bacteria from oysters destined for the half-shell market. The focus of this research was to investigate the efficacy of icing and high salinity exposure as two post-harvest treatments for the reduction in numbers of V. vulnificus and V. parahaemolyticus in commercial quantities of shellstock oysters. The icing experiment was conducted in the summer of 2006, and the high salinity trials …

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Differential Geometry In Cartesian Closed Categories Of Smooth Spaces, Martin Laubinger Jan 2008

Differential Geometry In Cartesian Closed Categories Of Smooth Spaces, Martin Laubinger

LSU Doctoral Dissertations

The main categories of study in this thesis are the categories of diffeological and Fr\"olicher spaces. They form concrete cartesian closed categories. In Chapter 1 we provide relevant background from category theory and differentiation theory in locally convex spaces. In Chapter 2 we define a class of categories whose objects are sets with a structure determined by functions into the set. Fr\"olicher's $M$-spaces, Chen's differentiable spaces and Souriau's diffeological spaces fall into this class of categories. We prove cartesian closedness of the two main categories, and show that they have all limits and colimits. We exhibit an adjunction between the …

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Model-Driven Search-Based Loop Fusion Optimization For Handwritten Code, Pamela Bhattacharya Jan 2008

Model-Driven Search-Based Loop Fusion Optimization For Handwritten Code, Pamela Bhattacharya

LSU Master's Theses

The Tensor Contraction Engine (TCE) is a compiler that translates high-level, mathematical tensor contraction expressions into efficient, parallel Fortran code. A pair of optimizations in the TCE, the fusion and tiling optimizations, have proven successful for minimizing disk-to-memory traffic for dense tensor computations. While other optimizations are specific to tensor contraction expressions, these two model-driven search-based optimization algorithms could also be useful for optimizing handwritten dense array computations to minimize disk to memory traffic. In this thesis, we show how to apply the loop fusion algorithm to handwritten code in a procedural language. While in the TCE the loop fusion …

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Swamp Ecology In A Dynamic Coastal Landscape: An Investigation Through Field Study And Simulation Modeling, Susanne Sigrid Hoeppner Jan 2008

Swamp Ecology In A Dynamic Coastal Landscape: An Investigation Through Field Study And Simulation Modeling, Susanne Sigrid Hoeppner

LSU Doctoral Dissertations

Increased flooding, nutrient and sediment deprivation, and saltwater intrusion have been implicated as probable causes of coastal swamp deterioration in the Mississippi Delta. An understanding of the interactive effects of these factors is required to enable successful planning of wetland restoration activities. I used field data collected from 2000 till 2005 at forty study sites to characterize the baseline conditions of the Maurepas swamp. I used a cluster analysis to identify four swamp habitat clusters, and characterized the clusters on the basis of soil properties, salinity, basal area, stem density, and other tree-related variables. ANOVA and related statistical techniques showed …

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Retro Models Of The Cisplatin-Dna Cross-Link With Carrier Ligands Having Sp2 N-Donor Triazine Rings, Vidhi Maheshwari Jan 2008

Retro Models Of The Cisplatin-Dna Cross-Link With Carrier Ligands Having Sp2 N-Donor Triazine Rings, Vidhi Maheshwari

LSU Doctoral Dissertations

Rapid rotation of guanine base derivatives about Pt–N7 bonds results in fluxional behavior of models of the key DNA intrastrand G–G cross-link leading to anticancer activity of Pt(II) drugs (G = deoxyguanosine). This behavior impedes the characterization of LPtG2 models (L = one bidentate or two cis-unidentate carrier ligands; G = guanine derivative). The objective of this study is to understand the types of conformers formed as L is systematically varied. This work, relevant to Pt(II) anticancer drugs, has evolved from published studies with sp3 N-ligands (e.g., 2,2'-bipiperidine), to C2 symmetrical or unsymmetrical sp2 N-ligands having pyridine and/or triazine rings. …

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Wetland Mitigation Banks And The No-Net-Loss Requirement: An Evaluation Of The Section 404 Permit Program In Southeast Louisiana, Abbey Anne Tyrna Jan 2008

Wetland Mitigation Banks And The No-Net-Loss Requirement: An Evaluation Of The Section 404 Permit Program In Southeast Louisiana, Abbey Anne Tyrna

LSU Master's Theses

Section 404 of the Clean Water Act provides regulatory oversight for wetland conservation. One goal of the Section 404 program is to achieve a no-net-loss of the remaining wetland acres and functions. Wetland mitigation banks have been incorporated into wetland policy because of their potential advantage in achieving the no-net-loss requirements. This study analyzed four wetland mitigation banks with credits sold between 1991 and 2007 in southeastern Louisiana to determine if they were contributing to the goal of no-net-loss. The goal of no-net-loss is reached when there is complete compensation of wetland structure and function. The study area for this …

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Novel Devices And Protocols Enabling Isolation And Enumeration Of Low Abundant Biological Cells From Complex Matrices, Andre Antonio Adams Jan 2008

Novel Devices And Protocols Enabling Isolation And Enumeration Of Low Abundant Biological Cells From Complex Matrices, Andre Antonio Adams

LSU Doctoral Dissertations

The dimensions of microfluidic devices closely parallel those of biological cells; thusly, they are excellent platforms for the speciation, transport, manipulation, and analysis of cells. Electrokinetic transport of Escherichia coli and Saccharomyces cerevisiae was evaluated in microfluidic devices fabricated in pristine and UV-modified poly(methylmethacrylate) and polycarbonate. The magnitude and direction of transport of the cells was dictated by the buffer composition, conduit surface chemistry, and intrinsic cellular electrical properties. Baker’s yeast in all devices migrated toward the cathode, because of their smaller electrophoretic mobility compared to the electroosmotic flow of the polymer. E. coli cells suspended in 20 mM PBS …

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Deciphering Controls On Polyphase Intraplate Deformation In The Ertomiao Region, Lang Shan, North-Central China, Michael Blevins Jan 2008

Deciphering Controls On Polyphase Intraplate Deformation In The Ertomiao Region, Lang Shan, North-Central China, Michael Blevins

LSU Master's Theses

The Ertomiao region of the Lang Shan, China, is located approximately 700 km west of Beijing, in the north-central portion of the North China block. This area is characterized by multiple periods of deformation, including periods of extension and contraction, spanning from Permian through Cenozoic time. This setting provides the structural relationships necessary to decipher the controls of polyphase crustal deformation. During fieldwork key structural observations and crosscutting relationships were established. Beginning with a period of contraction, northeast striking post Jurassic, pre Early Cretaceous (123 ma) thrust faults place Precambrian gneiss (unit PCB) onto Jurassic/Cretaceous sandstone and conglomerate (unit Jr/K). …

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Opportunities And Challenges Associated With Development Of Wood Biomass Energy Production In Louisiana, Anil Raj Kizhakkepurakkal Jan 2008

Opportunities And Challenges Associated With Development Of Wood Biomass Energy Production In Louisiana, Anil Raj Kizhakkepurakkal

LSU Master's Theses

Wood residue produced by forest products industry has been recognized as a potential fuel that can generate energy to run the industry. A survey was done among forest products industry to get a general idea about energy produced from woody biomass created from forest industry in Louisiana, USA. The industry was classified into primary and secondary forest products industry. The study provided information regarding utilization and wastage of wood residue. Survey response rate was 25 percent. It addressed problems faced by wood residue energy development and came up with solution to solve them. When survey results were compared to previous …

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The Impact Of The Caernarvon Diversion On Above- And Belowground Marsh Biomass In The Breton Sound Estuary After Hurricane Katrina, Matthew Korbel Moerschbaecher Jan 2008

The Impact Of The Caernarvon Diversion On Above- And Belowground Marsh Biomass In The Breton Sound Estuary After Hurricane Katrina, Matthew Korbel Moerschbaecher

LSU Master's Theses

The purpose of this project was to monitor the recovery of marsh vegetation following Hurricane Katrina in the Breton Sound estuary, which is directly influenced by the Caernarvon freshwater diversion. From March 2006 until October 2007, we measured above- and belowground biomass, soil porewater nutrients (NOx, NH4, and PO4), porewater salinity, porewater sulfide concentrations, and soil redox potential bimonthly at duplicate Near (N), Intermediate (M), and Far (F) sites (with respect to the diversion), as well as at a Reference (C) site. End of season live (EOSL) below and above ground biomass was measured at 26 separate stations where vegetation …

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A Multi-Scale Assessment Of Den Selection Of Louisiana Black Bears (Ursus Americanus Luteolus) In Northern And Central Louisiana, Annelie Crook Crook Jan 2008

A Multi-Scale Assessment Of Den Selection Of Louisiana Black Bears (Ursus Americanus Luteolus) In Northern And Central Louisiana, Annelie Crook Crook

LSU Master's Theses

Understanding den selection for the Louisiana black bear (Ursus americanus luteolus) may provide insight into habitat requirements of the subspecies and assist in conservation and management efforts. With that goal, I assessed den selection of female Louisiana black bears at multiple spatial scales in northern and central Louisiana. I used 230 den-years to examine den type (tree or ground), microhabitat characteristics at dens, and effects of landscape characteristics on den selection. We also evaluated tree availability and reuse. Solitary and parturient females selected tree dens more frequently (65%) than ground dens. However, tree dens were not required for successful denning …

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Long-Term Subsidence And Compaction Rates: A New Model For The Michoud Area, South Louisiana, Clint H. Edrington Jan 2008

Long-Term Subsidence And Compaction Rates: A New Model For The Michoud Area, South Louisiana, Clint H. Edrington

LSU Master's Theses

This study examined the stratigraphic record of the Michoud area in East New Orleans, Louisiana to address questions concerning the magnitude of, and processes leading to land-surface subsidence. The hypotheses under review are based on recent geodetic studies, which challenge the widely held position that modern subsidence is primarily a function of shallow sediment compaction. Testing these hypotheses involved constructing a structural cross section of the Michoud area using well logs, chronostratigraphic data, and fault picks, so as to evaluate differential motion along specific faults through time. Employing ages and corrected depths for three key subsurface horizons, long-term (Middle Miocene …

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Pileated Woodpeckers (Dryocopus Pileatus) And Saproxylic Beetles In Partial Cut And Uncut Bottomland Hardwood Forests, Patricia Jean Newell Jan 2008

Pileated Woodpeckers (Dryocopus Pileatus) And Saproxylic Beetles In Partial Cut And Uncut Bottomland Hardwood Forests, Patricia Jean Newell

LSU Master's Theses

Relative abundance and species richness of saproxylic beetles and nesting, roosting, and foraging ecology of pileated woodpeckers were studied in recent partial cuts and uncut forest during the summers of 2006 and 2007. Relative abundance of saproxylic beetles was greater in one-year old cuts than uncut forest during 2006 but was not consistent during 2007. The number of dead trees, period of capture, and trapping year also influenced beetle abundance. Species richness was similar in partial cuts and uncut forest. Characteristics of habitat used by pileated woodpeckers for nesting and roosting in one-year-old and two-year-old partial cuts and uncut forest …

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Laplace Transform Inversion And Time-Discretization Methods For Evolution Equations, Koray Ozer Jan 2008

Laplace Transform Inversion And Time-Discretization Methods For Evolution Equations, Koray Ozer

LSU Doctoral Dissertations

In this dissertation, we introduce Post-Widder-type inversion methods for the Laplace transform based on A-stable rational approximations of the exponential function. Since the results hold for Banach-space-valued functions, they yield efficient time-discretization methods for evolution equations of convolution type; e.g., linear first and higher order abstract Cauchy problems, inhomogeneous Cauchy problems, delay equations, Volterra and integro-differential equations, and problems that can be re-written as an abstract Cauchy problem on an appropriate state space.

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Visual Language Representation For Use Case Evolution And Traceability, Coretta Willis Douglas Jan 2008

Visual Language Representation For Use Case Evolution And Traceability, Coretta Willis Douglas

LSU Doctoral Dissertations

The primary goal of this research is to assist non-technical stakeholders involved in requirements engineering with a comprehensible method for managing changing requirements within a specific domain. An important part of managing evolving requirements over time is to maintain a temporal ordering of the changes and to support traceability of the modifications. This research defines a semi-formal syntactical and semantic definition of such a method using a visual language, RE/TRAC (Requirements Evolution with Traceability), and a supporting formal semantic notation RE/TRAC-SEM. RE/TRAC-SEM is an ontological specification employing a combination of models, including verbal definitions, set theory and a string language …

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Chemical Analysis Of Polymer Blends Via Synchrotron X-Ray Tomography, Heath Alan Barnett Jan 2008

Chemical Analysis Of Polymer Blends Via Synchrotron X-Ray Tomography, Heath Alan Barnett

LSU Doctoral Dissertations

Material properties of industrial polymer blends are of great importance. X-ray tomography has been used to obtain spatial chemical information about various polymer blends. The spatial images are acquired with synchrotron X-ray tomography because of its rapidity, good spatial resolution, large field-of-view, and elemental sensitivity. The spatial absorption data acquired from X-ray tomography experiments is converted to spatial chemical information via a linear least squares fit of multi-spectral X-ray absorption data. A fiberglass-reinforced polymer blend with a new-generation flame retardant is studied with multi-energy synchrotron X-ray tomography to assess the blend homogeneity. Relative to other composite materials, this sample is …

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Synthesis And Surface Characterization Of Silica-Polypeptide Composite Particles, Erick Isael Soto-Cantu Jan 2008

Synthesis And Surface Characterization Of Silica-Polypeptide Composite Particles, Erick Isael Soto-Cantu

LSU Doctoral Dissertations

The synthesis and sequential surface characterization of silica-polypeptide composite particles is described. Nearly monodisperse colloidal silica cores were obtained by the alkaline hydrolysis of tetraethyl orthosilicate (TEOS). The hydrodynamic radius can be easily controlled in the range of ƒî 20-140 nm by the water/TEOS ratio in the starting reaction mixture. The surface of the synthesized silica cores was further passivated/functionalized (P/F) by a mixture of (3-aminopropyl) trimethoxysilane (APS) and methyl-trimethoxysilane (MTMS). The amino groups were quantified using UV-Vis spectrometry after reaction with ninhydrin. The use of zeta potential measurements of the P/F silica particles at low pH is presented as …

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Fast Marching Methods - Parallel Implementation And Analysis, Maria Cristina Tugurlan Jan 2008

Fast Marching Methods - Parallel Implementation And Analysis, Maria Cristina Tugurlan

LSU Doctoral Dissertations

Fast Marching represents a very efficient technique for solving front propagation problems, which can be formulated as partial differential equations with Dirichlet boundary conditions, called Eikonal equation: $F(x)|\nabla T(x)|=1$, for $x \in \Omega$ and $T(x)=0$ for $x \in \Gamma$, where $\Omega$ is a domain in $\mathbb{R}^n$, $\Gamma$ is the initial position of a curve evolving with normal velocity F>0. Fast Marching Methods are a necessary step in Level Set Methods, which are widely used today in scientific computing. The classical Fast Marching Methods, based on finite differences, are typically sequential. Parallelizing Fast Marching Methods is a step forward for …

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Rice Straw Fiber Polymer Composites: Thermal And Mechanical Performance, Fei Yao Jan 2008

Rice Straw Fiber Polymer Composites: Thermal And Mechanical Performance, Fei Yao

LSU Doctoral Dissertations

Rice straw fiber can be considered as important potential reinforcing filler for thermoplastic composite because of its lignocellulosic characteristics. It is thus of practical significance to understand and predict the thermal decomposition process of rice straw fibers. A method proposed by Málek, Šesták, and co-workers was used to investigate and model thermal decomposition process of common natural fibers with detailed analysis on rice straw system. Assuming a global model occurring within the entire degradation of natural fibers with consideration of fiber as one pseudo-component, model can be used to describe both isothermal and non-isothermal degradation process of most selected fibers …

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Limit On The Muon Neutrino Magnetic Moment And A Measurement Of The Ccpip To Ccqe Cross Section Ratio, Serge Arisitde Ouedraogo Jan 2008

Limit On The Muon Neutrino Magnetic Moment And A Measurement Of The Ccpip To Ccqe Cross Section Ratio, Serge Arisitde Ouedraogo

LSU Doctoral Dissertations

A search for the muon neutrino magnetic moment was conducted using the Mini- BooNE low energy neutrino data. The analysis was performed by analyzing the elastic scattering interactions of muon neutrinos on electrons. The analysis looked for an excess of elastic scattering events above the Standard Model prediction from which a limit on the neutrino magnetic could be set. In this thesis, we report an excess of 15.3}6.6(stat)}4.1(syst) elastic scattering events above the expected background. At 90% C.L., we derived a limit on the muon neutrino magnetic moment of 12.7~ 10−10ƒÊB. The other analysis reported in this thesis is a …

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Designing Surface Chemistries For In Situ Afm Investigations Of Biomolecular Reactions With Proteins At The Nanoscale, Johnpeter Ndiangui Ngunjiri Jan 2008

Designing Surface Chemistries For In Situ Afm Investigations Of Biomolecular Reactions With Proteins At The Nanoscale, Johnpeter Ndiangui Ngunjiri

LSU Doctoral Dissertations

In situ atomic force microscopy (AFM) characterizations and lithography can be applied to investigate the orientation, reactivity and stability of protein molecules adsorbed on nanostructures of self-assembled monolayers at near-physiological conditions. Automated nanografting was used to fabricate regular arrays of nanopatterns of ù-functionalized n-alkanethiols with designated terminal chemistries. After writing nanopatterns, protein binding occurs selectively on carboxylate-terminated nanopatterns via covalent bonds that are formed using N-ethyl-N'(dimethylaminoporpyl)-carbodiimide and N-hydroxysuccinimide activation. The amine groups of lysine residues of proteins bond covalently to nanopatterns of carboxylate-terminated alkanethiol self-assembled monolayers, to form a robust surface attachment for sustained contact-mode AFM imaging during biochemical reactions. …

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Assessment Of Oxygen Sources And Sinks In The Northern Gulf Of Mexico Using Stable Oxygen Isotopes, Zoraida Jazmin Quinones-Rivera Jan 2008

Assessment Of Oxygen Sources And Sinks In The Northern Gulf Of Mexico Using Stable Oxygen Isotopes, Zoraida Jazmin Quinones-Rivera

LSU Doctoral Dissertations

Coastal hypoxia (< 2 mg O2L-1) represents a global problem that continues to worsen as nutrient fluxes to these areas increase. The second largest zone of human-induced hypoxia is located on the Louisiana continental shelf where hypoxic bottom waters commonly occur during summertime. This region is strongly impacted by the large flux of freshwater and nutrients from the Mississippi River, which influences both biological and physical processes that control oxygen dynamics. Yet, based on oxygen concentration measurements alone, it is difficult to separate the effects of biological factors from physical factors. To address this problem, I used a dual budget approach to assess the importance of oxygen sources and sinks on the Louisiana continental shelf. The dual budget was based on using stable oxygen isotopes (ä18O) in combination with conventional oxygen concentration measurements. To analyze temporal trends, surface and bottom water samples were collected monthly between July 2001 and July 2003 along an onshore-offshore transect. For better spatial resolution, shelfwide sampling was conducted extending from the Mississippi River Delta to the Louisiana-Texas border in the month of July of 2001, 2002, and 2003. Oxygen saturations values ranged between 180% at the surface and almost 0% close to the bottom with a corresponding range of ä18O values from 15‰ to 50‰. Biological parameters were important during all seasons for surface oxygen dynamics. The effects of physical factors were less apparent, except during severe physical disturbances. Bottom water oxygen dynamics showed clear seasonal signals of high oxygen depletion and larger contributions of benthic respiration during the summer, which corresponded to the strong stratification of the water column. In bottom waters, summer oxygen depletion was predominantly due to benthic respiration, accounting for about 73%, 80% and 60% of the total oxygen loss for 2001, 2002 and 2003 respectively. Model estimates of production/respiration (P/R) ratio during the July shelfwide cruises indicated that surface waters were productive with an average calculated P/R above 1. Depth stratified sampling (5 m intervals), which started in July 2002, showed that productivity in the mixed layer (5 to 10 m) was not homogeneous. Calculated P/R exceeded 1 only in the surface layer, while at 5 m P/R was approximately 1 and at a depth of 10 m, P/R was less than 1. Additionally, hypoxic conditions were only detected within 5 m of the bottom sediments. The dual budget approach yielded new estimates of productivity dynamics in surface waters and of sediment oxygen demand in bottom waters. For the first time, this study provided routine insight into productivity and respiration dynamics over large temporal and spatial scales. This could not have been accomplished using traditional methods because they commonly rely on time-consuming incubations. The study has shown that respiration dynamics in bottom waters vary seasonally with higher contribution of benthic respiration during stratified summer conditions and prevalent water column respiration during fall and winter. In contrast, seasonality in surface waters was less pronounced as productivity was more dependent on (salinity-inferred) nutrient supply than climatic forcing.

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Exploration Of New Ternary Gallides And Investigation Of Their Structure-Property Relationships, Jung Young Cho Jan 2008

Exploration Of New Ternary Gallides And Investigation Of Their Structure-Property Relationships, Jung Young Cho

LSU Doctoral Dissertations

This dissertation focuses on the investigation of new ternary intermetallic gallides, which may exhibit exotic physical properties such as heavy-fermion behavior, large magnetoresistance, and even superconductivity. In particular, the Ln-Cu-Ga (Ln = lanthanides) system has been systematically investigated by changing a reaction ratio and/or using a different temperature profile to optimize desired phases. Single crystals of Ln2MGa12 (Ln = La, Ce; M = Ni, Cu) have been synthesized using Ga flux and compared to their Pd analogues. Interestingly, Ce2MGa12 (M = Ni, Cu) show enhanced Sommerfeld coefficient of ¡Ö 191 mJmol-1K-2 and ¡Ö 69 mJmol-1K-2 for Ni and Cu compounds, …

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Towards An Extended Microscopic Theory For Upper-Fp-Shell Nuclei, Kalin Drumev Jan 2008

Towards An Extended Microscopic Theory For Upper-Fp-Shell Nuclei, Kalin Drumev

LSU Doctoral Dissertations

An extended SU(3) shell model that for the first time explicitly includes particles from the unique-parity levels in nuclei is introduced. Its relevance is established through calculations performed with realistic interactions for a group of upper fp-shell isotopes where valence nucleons beyond the N=28=Z core occupy levels of the normal-parity upper $fp$-shell ($f_{5/2},p_{3/2},p_{1/2}$) and the unique-parity $g_{9/2}$ intruder configuration. Specifically, the outcome suggests that the pseudo-SU(3) symmetry is quite good throughout the region and that only part of the configurations are relevant for the structure of the low-lying states. The levels of the upper $fp$-shell are handled within the framework …

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Syntheses Of Trimethylamine- And Phosphonate- Substituted Carboranylporphyrins For Application In Boron Neutron Cancer Therapy, Michael William Easson Jan 2008

Syntheses Of Trimethylamine- And Phosphonate- Substituted Carboranylporphyrins For Application In Boron Neutron Cancer Therapy, Michael William Easson

LSU Doctoral Dissertations

Chapter 1 contains an introduction to porphyrins and carboranylporphyrins, including their physical properties, history, methods of synthesis, medicinal applications, and an overview of recently published compounds. Chapter 2 contains the total synthesis of a series of trimethylamine- and phosphonate-substituted carboranylporphyrins for application in boron neutron capture therapy (BNCT), including characterization by proton nuclear magnetic resonance spectroscopy, matrix-assisted time-of-flight mass spectroscopy, high resolution mass spectroscopy, UV-Vis spectrophotometry, X-ray crystallography, and melting point apparatus. Chapter 3 contains synthetic methods which were investigated as alternate routes to porphyrin synthesis and functionalization. Chapter 4 presents the in vitro biological evaluation of trimethylamine- and phosphonate-substituted …

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A Study Of Rheological And Thermodynamic Properties Of Polymer-Clay Gels And Multilayered Films, Eduard Adrian Stefanescu Jan 2008

A Study Of Rheological And Thermodynamic Properties Of Polymer-Clay Gels And Multilayered Films, Eduard Adrian Stefanescu

LSU Doctoral Dissertations

The overall objective of the research presented here is to understand the nanoscopic and microscopic structures that exist in dispersions of laponite and montmorillonite in poly(ethylene oxide), (PEO) and to correlate their shear responses with the final structure and properties of multilayered nanocomposite films prepared from these dispersions. These structures were examined as a function of polymer molecular weight, polymer and clay concentrations, and type of clay used to prepare the nanocomposites. A sequence of shear and elongational rheological measurements is used to provide a more complete physical picture on the structure of polymer-clay hydrogels, while a combination of techniques …

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Evidence For Symplectic Symmetry In Ab Initio No-Core Shell Model Results, Tomas Dytrych Jan 2008

Evidence For Symplectic Symmetry In Ab Initio No-Core Shell Model Results, Tomas Dytrych

LSU Doctoral Dissertations

Advances in the construction of realistic internucleon interactions together with the advent of massively parallel computers have resulted in a successful utilization of the ab initio approaches to the investigation of properties of light nuclei. The no-core shell model is a prominent ab initio method that yields a good description of the low-lying states in few-nucleon systems as well as in more complex p-shell nuclei. Nevertheless, its applicability is limited by the rapid growth of the many-body basis with larger model spaces and increasing number of nucleons. To extend the scope of the ab initio no-core shell model to heavier …

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The Synthesis Of Water Soluble N-Acyl Chitosan Derivatives For Characterization As Antibacterial Agents, Lakia Monique Champagne Jan 2008

The Synthesis Of Water Soluble N-Acyl Chitosan Derivatives For Characterization As Antibacterial Agents, Lakia Monique Champagne

LSU Doctoral Dissertations

Currently, natural polysaccharides are being utilized increasingly in the markets because they exhibit biodegradability, biocompatibility, versatility, and are found abundant in nature. The diversity of natural polysaccharides provides the chemist with a broad spectrum of raw materials that can be used in many biological applications. Chitosan is a natural polysaccharide that possesses excellent biological properties. It has been recognized for its antibacterial activity, in that it is destructive towards the bacterium Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The antibacterial property of chitosan can be enhanced by changing the hydrophobic/hydrophilic nature of the polysaccharide backbone. This research entails …

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Surgery Description Of Colored Knots, Steven Daniel Wallace Jan 2008

Surgery Description Of Colored Knots, Steven Daniel Wallace

LSU Doctoral Dissertations

By a knot, or link, we mean a circle, or a collection of circles, embedded in the three-sphere S3. The study of knots is a very rich subject and plays a key role in the area of low-dimensional topology. In fact, a theorem of W.B.R. Lickorish and A.D. Wallace states that any three-dimensional manifold may be described by Dehn surgery along a link which is the process of removing the link from S3 and then gluing it back in a way that possibly changes the resulting manifold. In this dissertation, we will be interested in the pair (K, ρ) consisting …

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Identification Of Quantitative Trait Loci Influencing Early Height Growth In Longleaf Pine (Pinus Palustris Mill), Lisha Wu Jan 2008

Identification Of Quantitative Trait Loci Influencing Early Height Growth In Longleaf Pine (Pinus Palustris Mill), Lisha Wu

LSU Doctoral Dissertations

The delay in early height growth (EHG) has been a limiting factor for artificial regeneration of longleaf pine (Pinus palustris Mill.). Simple Sequence Repeat (SSR) markers have been used to map the genome and quantitative trait loci controlling the EHG in a backcross family (longleaf pine x slash pine) x longleaf pine. A total of 228 locus specific SSR markers were screened against 6 longleaf pine recurrent parents and a sample of 7 longlef x slash pine hybrid parents. In total, 135 polymorphic markers were identified. Based on the genetic variance in EHG, available sample size, and the number of …

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