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Articles 1141 - 1170 of 3417

Full-Text Articles in Physical Sciences and Mathematics

An Empirical Estimate Of Post-Lgm Grounding-Event Duration In Eastern Ross Sea: Implications From A Comparison With Constraints From New Radiocarbon Dates, Benjamin Krogmeier Jan 2016

An Empirical Estimate Of Post-Lgm Grounding-Event Duration In Eastern Ross Sea: Implications From A Comparison With Constraints From New Radiocarbon Dates, Benjamin Krogmeier

LSU Master's Theses

The West Antarctic Ice Sheet (WAIS) advanced to the outer shelf during the Last Glacial Maximum (LGM) before beginning a rapid retreat to the inner shelf. In the Whales Deep paleo-ice-stream trough, subsurface and geomorphologic evidence shows that grounding-line retreat was interrupted by at least five pauses in the area between the shelf edge and the middle shelf. During the pauses, an overlapping cluster of backstepped grounding zone wedges (GZWs) was deposited. Each GZW represents a grounding event, i.e., a time interval during which the grounding-line position was relatively stable. Seismic correlation and isopach mapping show that the cluster has …

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Spatiotemporal Distribution Of The Himalayan Leucogranite: Implications For Mountain-Building As A Function Of Indian Slab Dynamics, Hongcheng Guo Jan 2016

Spatiotemporal Distribution Of The Himalayan Leucogranite: Implications For Mountain-Building As A Function Of Indian Slab Dynamics, Hongcheng Guo

LSU Master's Theses

The Himalayan orogen, as a natural laboratory for continental collision, has attracted intense research attention for decades. However, the question of how the orogen was built is still debated, and potential answers are few when considering how and why along-strike variations of the mountain-building processes occurred. Various tectonic models have been proposed to explain the kinematics of the mountain-building. These models include two dimensional models, such as wedge extrusion (Burchfiel and Royden, 1985; Grujic et al., 1996; Kohn, 2008), channel flow coupled to focused denudation (Beaumont et al., 2001; Hodges et al., 2001), tectonic wedging (Yin, 2006; Webb et al., …

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Living On The Edge: An Assessment Of The Habitat Use Of Waterbirds In Estuarine Wetlands Of Barataria Basin, La, Brett Ashley Patton Jan 2016

Living On The Edge: An Assessment Of The Habitat Use Of Waterbirds In Estuarine Wetlands Of Barataria Basin, La, Brett Ashley Patton

LSU Master's Theses

The wetlands of Louisiana are losing area at the rapid rate of 42.9 km2 yr-1 and the trend is expected to continue. This combined with expected sea-level rise will likely cause large shifts in vegetation and salinity regimes that will affect the wildlife species reliant on these ecosystems. Waterbirds serve as indicator species of ecosystem health in estuarine wetland habitats; therefore, these species are often the targets of wetland management goals in Louisiana. However, many proposed wetland restoration projects are focused primarily on social impacts with only a few specific waterbird species designated for management. The majority of these waterbird …

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Interactions Among Hydrology, Sediment And Vegetation In Accreting Wax Lake Delta: Physical And Biogeochemical Implications For Coastal Louisiana Restoration, Courtney Erin Elliton Jan 2016

Interactions Among Hydrology, Sediment And Vegetation In Accreting Wax Lake Delta: Physical And Biogeochemical Implications For Coastal Louisiana Restoration, Courtney Erin Elliton

LSU Master's Theses

River discharge pulses, wind, waves, tides, and the presence of dense vegetation are factors that interact and regulate the transport and retention of sediment in coastal regions. In particular, vegetation structural and physiognomic traits promote fine sediment trapping during tidal and river flow, maintaining the balance between soil elevation and relative sea level rise on coastline stability and land building. Mike Island, located within Wax Lake Delta, Louisiana, USA, is part of a deltaic system created by a man-made freshwater diversion (1941) and one of few coastal areas where land is expanding in coastal Louisiana as result of pulsing river …

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Influences On The Successful Implementation Of The Convention On Wetlands Of International Importance (Ramsar) Among Member Countries, Aziza Saud Al Adhoobi Jan 2016

Influences On The Successful Implementation Of The Convention On Wetlands Of International Importance (Ramsar) Among Member Countries, Aziza Saud Al Adhoobi

LSU Master's Theses

Wetlands are very dynamic ecosystems and are featured all over the world’s landscape. Recent studies suggested that wetlands are in continuous decline, both and quantity and quality and between 64-71% is the estimated global wetland loss in the 20th century (Davidson 2014; Gardner et al., 2015). Therefore, as wetland loss increases around the world, more effort to protect and restore wetland habitat, values, and services become crucial. For this reason, the Ramsar Convention was established four decades ago to highlight the severity of wetland loss and to produce guidelines that aim to guide Contracting Parties toward sustainable and efficient management …

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Archean Geodynamic Conditions Using P-T Constraints Of The East Pilbara Craton Ttgs, Andrew Kody Webb Jan 2016

Archean Geodynamic Conditions Using P-T Constraints Of The East Pilbara Craton Ttgs, Andrew Kody Webb

LSU Master's Theses

We know very little about the tectonic setting present during the Hadean, but based on studies of surviving Hadean zircons, we know that a Hadean protocrust must have been established by at least 4.4 Ga (Kemp et al. 2010), and it must have also been able to accommodate minimum melt conditions (Harrison 2005). Tectonic models for Earth during the Hadean and Archean follow two trends: uniformitarianism and non-uniformitarianism. Uniformitarian models (following the famed geological concept that the present is the key to the past) argue that Hadean zircons and Archean rocks formed via processes akin to modern-style oceanic crust production …

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Applying Deep Learning Techniques To The Analysis Of Android Apks, Robin Andrew Nix Jan 2016

Applying Deep Learning Techniques To The Analysis Of Android Apks, Robin Andrew Nix

LSU Master's Theses

Malware targeting mobile devices is a pervasive problem in modern life and as such tools to detect and classify malware are of great value. This paper seeks to demonstrate the effectiveness of Deep Learning Techniques, specifically Convolutional Neural Networks, in detecting and classifying malware targeting the Android operating system. Unlike many current detection techniques, which require the use of relatively rigid features to aid in detection, deep neural networks are capable of automatically learning flexible features which may be more resilient to obfuscation. We present a parsing for extracting sequences of API calls which can be used to describe a …

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Using Tourmaline As An Indicator Of Provenance: Development And Application Of A Statistical Approach Using Random Forests, Erin Lael Walden Jan 2016

Using Tourmaline As An Indicator Of Provenance: Development And Application Of A Statistical Approach Using Random Forests, Erin Lael Walden

LSU Master's Theses

Tourmaline is a petrologic indicator mineral that is the major repository of boron in the earth’s crust. It forms readily when boron is present, accommodating multiple cations and anions with multiple possible substitutions for each site in the crystal structure. It is stable over a wide variety of pressures and temperatures, from near-surface P/T conditions to greater than 950 C and 7 GPa. It records information about conditions of formation, as well as pressure and temperature. Due to its resistance to chemical or physical weathering, and the negligible diffusion of elements in the crystal lattice, information about provenance is preserved. …

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Fishes Associated With Oil And Gas Platforms In Louisiana's River-Influenced Nearshore Waters, Ryan Thomas Munnelly Jan 2016

Fishes Associated With Oil And Gas Platforms In Louisiana's River-Influenced Nearshore Waters, Ryan Thomas Munnelly

LSU Master's Theses

A distinctive feature of coastal Louisiana is the unrivaled network of oil and gas installations (platforms) extending from inshore waters to the deep Gulf of Mexico. Since 2007 there has been a 38% reduction in platform numbers with the highest removal rates occurring in shallow (< 18 m) nearshore waters. Many fishes and invertebrates are attracted to platforms, presenting a unique opportunity to study detailed species-specific responses to the river-influenced hydrographic characteristics of Louisiana’s nearshore zone (5–25 km water depth). Prior studies of fishes around platforms focused on a few relatively large platforms in water depths ≥ 18 m. However, about one-third of all platforms are small, unmanned and non-drilling platforms located in waters < 18 m depth. Paired video and hydrographic data were collected at 150 small platforms in < 18 m water depth during the summers of 2013–2014. Fifty-four species of fishes were associated with small platforms. The assemblage(s) included juveniles of 29 species, indicating the importance of nearshore platforms as diverse nursery habitat. The coastal zone was divided into three regions based on broad-scale interactions between freshwater input and bathymetry driving major distinctions in interregional hydrography and fish assemblages. Co-occurring within this expansive artificial reef network is the second largest hypoxic area (dissolved oxygen (DO) < 2.0 mg l−1) on Earth. Platforms offer reef-like habitat features in the upper water column that may offer refugia for some reef-associated species during hypoxic events. Significant intraregional differences in physicochemical features were related to the presence of hypoxia (defined as DO < 50% saturation), as well as the distribution of sandy shoals. Eleven species accounted for most of the assemblage dissimilarities, composing ~93% of fishes observed. Habitat suitability indices for these 11 species provided information about habitat selection across horizontal and vertical physicochemical gradients throughout the coastal zone, and within hypoxic and well-oxygenated stratified water columns. East Bay, near the outlet of the Mississippi River, exhibited less hypoxia and a distinct fauna that included four adult goliath grouper (Epinephelus itajara). This endangered fish was observed during spawning season (summer), suggesting that East Bay might support a spawning aggregation.

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Complexity Theory And Its Applications In Linear Quantum Optics, Jonathan Olson Jan 2016

Complexity Theory And Its Applications In Linear Quantum Optics, Jonathan Olson

LSU Doctoral Dissertations

This thesis is intended in part to summarize and also to contribute to the newest developments in passive linear optics that have resulted, directly or indirectly, from the somewhat shocking discovery in 2010 that the BosonSampling problem is likely hard for a classical computer to simulate. In doing so, I hope to provide a historic context for the original result, as well as an outlook on the future of technology derived from these newer developments. An emphasis is made in each section to provide a broader conceptual framework for understanding the consequences of each result in light of the others. …

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Particulate Inorganic Carbon Flux And Sediment Transport Dynamics In Karst: Significance To Landscape Evolution And The Carbon Cycle., Randall Lee Paylor Jan 2016

Particulate Inorganic Carbon Flux And Sediment Transport Dynamics In Karst: Significance To Landscape Evolution And The Carbon Cycle., Randall Lee Paylor

LSU Doctoral Dissertations

Research focused on three areas of karst hydrogeology and sediment transport that have been poorly studied in the past: the role of particulate inorganic carbon transport in calculating carbon sink rates in karst; rapid changes in surface vs. subsurface sediment mixing in karst conduits; and comparison of landscape denudation calculations using dissolved carbonate load vs. total dissolved/sediment load. Carbonate bedrock weathering is a significant component of the atmospheric carbon sink. Particulate inorganic carbon (PIC) in bed and suspended sediment load of karst waters is frequently dismissed as insignificant for calculating denudation and carbon transport/sink rates, but PIC flux has not …

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Understanding Chemical Reactions In Novel Materials: From Metal Organic Frameworks To Oxyallyl Cations, Kiara Taylor-Edinbyrd Jan 2016

Understanding Chemical Reactions In Novel Materials: From Metal Organic Frameworks To Oxyallyl Cations, Kiara Taylor-Edinbyrd

LSU Doctoral Dissertations

The work of this dissertation investigates the chemical processes of novel materials through quantum mechanical calculations and molecular dynamics simulations. The first section of this work focuses on probing copper based metal organic frameworks (MOFs) for their ability to catalytically release nitric oxide from s-nitrosothiol (RSNO) precursors in a slow, controlled and sustained manner and compares these findings to a free copper ion/ethanol solution. Through the use of electronic structure calculations and molecular dynamics simulations, studies are carried out to better understand how the barriers of RSNOs approach to the catalytic copper center changes with modifications to the R-group (of …

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Quantum Radiation Pressure Noise: Exposing The Quantum Mechanics Of Optomechanical Interactions, Robinjeet Singh Jan 2016

Quantum Radiation Pressure Noise: Exposing The Quantum Mechanics Of Optomechanical Interactions, Robinjeet Singh

LSU Doctoral Dissertations

The detection of gravitational waves has further motivated the scientists to push horizons for an improved sensitivity sphere of the advanced LIGO. Below 100 Hz, design sensitivity of the advanced LIGO is predicted to be limited by the quantum backaction or the quantum radiation pressure noise (QRPN). In this thesis, I present the experimental progress towards the measurement of the QRPN. This work is in part an effort towards establishing a tabletop test experiment to calibrate the QRPN evasion through various proposed schemes, and further bring to light new nonlinear optomechanical dynamics. The experiment consists of a high optical and …

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Towards Theory And Applications Of Generalized Categories To Areas Of Type Theory And Categorical Logic, Lucius Traylor Schoenbaum Jan 2016

Towards Theory And Applications Of Generalized Categories To Areas Of Type Theory And Categorical Logic, Lucius Traylor Schoenbaum

LSU Doctoral Dissertations

Motivated by potential applications to theoretical computer science, in particular those areas where the Curry-Howard correspondence plays an important role, as well as by the ongoing search in pure mathematics for feasible approaches to higher category theory, we undertake a detailed study of a new mathematical abstraction, the generalized category. It is a partially defined monoid equipped with endomorphism maps defining sources and targets on arbitrary elements, possibly allowing a proximal behavior with respect to composition. We first present a formal introduction to the theory of generalized categories. We describe functors, equivalences, natural transformations, adjoints, and limits in the generalized …

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Exploration Of Bimetallic Nickel And Cobalt Complexes For Catalytic Oxidative Cleavage Of Alkenes And Hydroformylation, Ciera Vonn Duronslet Jan 2016

Exploration Of Bimetallic Nickel And Cobalt Complexes For Catalytic Oxidative Cleavage Of Alkenes And Hydroformylation, Ciera Vonn Duronslet

LSU Doctoral Dissertations

The “old” bimetallic nickel complexes, meso- and rac-Ni2Cl4(et,ph-P4) were investigated as possible “catalysts” for the oxidative cleavage of alkenes using an unsaturated fatty acid, oleic acid, as the substrate. The “new” bimetallic nickel complexes with a stronger chelating tetraphosphine ligand, meso- and rac-Ni2Cl4(et,ph-P4-Ph), were also synthesized and tested for the oxidative cleavage of oleic acid. All four dinickel complexes were found to be active for the oxidative cleavage of oleic acid, producing extremely small amounts of aldehyde product. The Stanley research group also discovered the oxidative cleavage of alkenes using only the “old” et,ph-P4 tetraphosphine ligands with no metal centers. …

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Synthesis And Characterization Of Cyclic Polypeptoids By Organo-Mediated Controlled Zwitterionic Ring-Opening Polymerization And Development Of Redox-Responsive Polypeptoid Micelles As Drug Delivery Carriers, Ang Li Jan 2016

Synthesis And Characterization Of Cyclic Polypeptoids By Organo-Mediated Controlled Zwitterionic Ring-Opening Polymerization And Development Of Redox-Responsive Polypeptoid Micelles As Drug Delivery Carriers, Ang Li

LSU Doctoral Dissertations

Peptoids are peptidomimetic polymers, which have attracted much attention over the past two decades. They have similar building blocks to peptides, and the similarity makes the backbone of peptoids hydrophilic and biocompatible.1 Two types of peptoid polymers are under development. One is sequence-defined peptoids, which exhibit excellent bioactivities.2 Another one is polypeptoids. The good biocompatibility and highly tunable side chain substituents allow polypeptoids to be used broadly in future biomedical applications. Varying polymer architectures, including linear polymers, cyclic polymers, comb-like polymers, and dendrimers can provide distinctive properties to the polymers. Cyclic polymers employ a cyclic architecture and lack chain ends, …

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Fairness And Approximation In Multi-Version Transactional Memory., Basem Ibrahim Assiri Jan 2016

Fairness And Approximation In Multi-Version Transactional Memory., Basem Ibrahim Assiri

LSU Doctoral Dissertations

Shared memory multi-core systems bene_x000C_t from transactional memory implementations due to the inherent avoidance of deadlocks and progress guarantees. In this research, we examine how the system performance is a_x000B_ected by transaction fairness in scheduling and by the precision in consistency. We _x000C_rst explore the fairness aspect using a Lazy Snapshot (multi-version) Algorithm. The fairness of transactions scheduling aims to balance the load between read-only and update transactions. We implement a fairness mechanism based on machine learning techniques that improve fairness decisions according to the transaction execution history. Experimental analysis shows that the throughput of the Lazy Snapshot Algorithm is …

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Hybrid Inorganic Core- Conjugated Polymer Shell Nanoparticles Prepared By Surface-Initiated Polymerization, Sourav Chatterjee Jan 2016

Hybrid Inorganic Core- Conjugated Polymer Shell Nanoparticles Prepared By Surface-Initiated Polymerization, Sourav Chatterjee

LSU Doctoral Dissertations

Hybrid core-shell nanoparticles have attracted attention due to their unique characteristics which combine properties of the inorganic core and organic shell in a way that generates new properties which do not exist for the two individual parts. This makes them promising candidates for the design of stimuli-responsive materials, chemo- and biosensors, and various biomedical applications. In this dissertation research, we designed and prepared a series of hybrid environmentally responsive nanoparticles where fluorescent block copolymers, including various combinations of polythiophene (PT), poly(p-phenylene) (PPP), poly(3-hexylthiophene) (P3HT) and polyallene (PA), were grafted on the surface of inorganic nanoparticles using surface-confined Kumada catalyst-transfer polymerization. …

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Ecological-Hydrological Feedback In Forested Wetlands, Scott Thomas Allen Jan 2016

Ecological-Hydrological Feedback In Forested Wetlands, Scott Thomas Allen

LSU Doctoral Dissertations

In forested wetlands, the biotic and abiotic consequences of water level variability is not well understood. The effects of flooding on carbon and water exchanges are important knowledge gaps where progress could benefit management of natural resources and predicting of changes in surface geophysical cycles. Two specific needs are a better understanding of (1) wetland tree responses to hydrologic variations, and (2) the effects of the forest and associated tree stressors on surface energy and water fluxes. Objectives were to determine effects of flooding on evaporation rates and energy dynamics, tree water use and growth responses to river-floodplain connectivity and …

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Ultrafast And Nonlinear Spectroscopy Of Colloidal Nanomaterials, Tony Eugene Karam Jan 2016

Ultrafast And Nonlinear Spectroscopy Of Colloidal Nanomaterials, Tony Eugene Karam

LSU Doctoral Dissertations

In the first part of this dissertation, the adsorption isotherms, resonance coupling, and fluorescence of molecular dyes on the surface of plasmonic nanoparticles are investigates. SHG is also used to investigate the growth of a silver shell on the surface of gold nanoparticles in real time. Additionally, gold-silver-gold core-shell-shell nanoparticles possess extinction peak wavelengths that can be controlled over the visible and near-infrared regions and enhanced photothermal effect. Transient absorption measurements determine that the phonon-phonon scattering lifetime is considerably faster in the core-shell-shell nanoparticles than in the gold nanospheres and gold nanorods, which contributes to the higher photothermal efficiencies. Transient …

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High-Resolution Correlation Using Geophysical And Geochemical Methods On Three Cambrian Drumian Marine Sedimentary Successions In The House Range Embayment, Western Laurentia, Emad I. Elfar Jan 2016

High-Resolution Correlation Using Geophysical And Geochemical Methods On Three Cambrian Drumian Marine Sedimentary Successions In The House Range Embayment, Western Laurentia, Emad I. Elfar

LSU Doctoral Dissertations

The Global boundary Stratotype Section and Point (GSSP) of the base of the Cambrian Drumian Stage was defined at 62 m above the base of the Wheeler formation, at the First Appearance Datum (FAD) of Ptychagnostus atavus (P. atavus), and at 10 meter below the DrumIan Carbon isotope Excursion (DICE) on the Stratotype Ridge in the Drum Mountains western Utah, (Babcock at al., 2004; 2007). Tracing the base of the the Drumian stage to other Middle Cambrian sequences in the House Range Embayment (HRE), a fault-controlled deep-water intrusion into an extensive carbonate platform along the passive margin of western Laurentia, …

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Derived Geometric Satake Equivalence, Springer Correspondence, And Small Representations, Jacob Paul Matherne Jan 2016

Derived Geometric Satake Equivalence, Springer Correspondence, And Small Representations, Jacob Paul Matherne

LSU Doctoral Dissertations

It is known that the geometric Satake equivalence is intimately related to the Springer correspondence when restricting to small representations of the Langlands dual group (see a paper by Achar and Henderson and one by Achar, Henderson, and Riche). This dissertation relates the derived geometric Satake equivalence of Bezrukavnikov and Finkelberg and the derived Springer correspondence of Rider when we restrict to small representations of the Langlands dual group under consideration. The main theorem of the before-mentioned paper of Achar, Henderson, and Riche sits inside this derived relationship as its degree zero piece.

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Quantitative Oil Source-Fingerprinting Techniques And Their Application To Differentiating Crude Oil In Coastal Marsh Sediments, Buffy Marie Meyer Jan 2016

Quantitative Oil Source-Fingerprinting Techniques And Their Application To Differentiating Crude Oil In Coastal Marsh Sediments, Buffy Marie Meyer

LSU Doctoral Dissertations

Oil source-fingerprinting is an environmental forensics technique that uses analytical chemistry to determine the origin of oil residues in environmental samples by comparison to a known or suspected source oil. Currently, the only standardized method for oil source fingerprinting is a qualitative approach that is very effective in almost every oil spill response situation. However, the need for quantitative oil source-fingerprinting methods to complement the qualitative determinations is extremely desired. The research herein aims to utilize data generated by gas chromatography/mass spectrometry (GC/MS) methodologies to test two different quantitative techniques: diagnostic biomarker ratio analysis and chemometrics. The most common crude …

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Variability Of Optical Counterparts To X-Ray Sources Within The Galactic Bulge Survey, Christopher Bradley Johnson Jan 2016

Variability Of Optical Counterparts To X-Ray Sources Within The Galactic Bulge Survey, Christopher Bradley Johnson

LSU Doctoral Dissertations

The Chandra Galactic Bulge Survey (GBS) is a shallow, wide field survey to search for and classify X-ray sources in the Galactic Bulge. Specifically, we are looking for Low Mass X-ray Binaries (LMXBs): systems containing either a neutron star or black hole that is accreting matter from a roughly stellar mass companion via Roche-Lobe overflow. My research uses optical, time-series photometry from the DECam instrument on the Blanco 4.0 m telescope at the Cerro Tololo Inter-American Observatory to identify counterparts to new X-ray sources in the GBS. For the systems that are variable in brightness in the optical, I use …

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Arsenic Speciation And Phytoremediation Modeling For Environmental Management, Sidney Joseph Marlborough Jan 2016

Arsenic Speciation And Phytoremediation Modeling For Environmental Management, Sidney Joseph Marlborough

LSU Doctoral Dissertations

Arsenic has been used throughout recorded history but during the industrial revolution widespread use led to global environmental impact. The two forms that should be considered in environment management are arsenate and arsenite. The calculations of environmental risk for arsenic exposure relies the toxicity of arsenite however, in well aeriated surface soils arsenate may be the predominate form. Ecological risk assessments based on arsenite studies will lead to restrictive remediation requirements that do not adequately reflect the level of risk. Arsenate resembles phosphate and as such has a greater affinity for phytoremediation. Phytoremediation is one of the most viable and …

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Advances In Quantum Metrology: Continuous Variables In Phase Space, Bryan Tomas Gard Jan 2016

Advances In Quantum Metrology: Continuous Variables In Phase Space, Bryan Tomas Gard

LSU Doctoral Dissertations

This dissertation serves as a general introduction to Wigner functions, phase space, and quantum metrology but also strives to be useful as a how-to guide for those who wish to delve into the realm of using continuous variables, to describe quantum states of light and optical interferometry. We include many of the introductory elements one needs to appreciate the advantages of this treatment as well as show many examples in an effort to make this dissertation more friendly. In the initial segment of this dissertation, we focus on the advantages of Wigner functions and their use to describe many quantum …

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Beyond The Tails Of The Colored Jones Polynomial, Jun Peng Jan 2016

Beyond The Tails Of The Colored Jones Polynomial, Jun Peng

LSU Doctoral Dissertations

In [2] Armond showed that the heads and tails of the colored Jones polynomial exist for adequate links. This was also shown independently by Garoufalidis and Le for alternating links in [8]. Here we study coefficients of the "difference quotient" of the colored Jones polynomial. We begin with the fundamentals of knot theory. A brief introduction to skein theory is also included to illustrate those necessary tools. In Chapter 3 we give an explicit expression for the first coefficient of the relative difference. In Chapter 4 we develop a formula of t_2, the number of regions with exactly 2 crossings …

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Design And Implementation Of Qcm Virtual Sensing Schemes For Analyses Of Volatile Organic Compounds, Nicholas Colby Speller Jan 2016

Design And Implementation Of Qcm Virtual Sensing Schemes For Analyses Of Volatile Organic Compounds, Nicholas Colby Speller

LSU Doctoral Dissertations

Sensor arrays have evolved as powerful approaches for providing detection and discrimination of volatile organic compounds (VOCs) as required across numerous analytical applications. Such systems typically comprise a number of cross reactive sensor elements, which generate analyte specific response patterns upon exposure to VOCs, and are known as multisensor arrays. When evaluated using statistical methods, these response patterns facilitate classification of VOCs. As an alternative, a single dynamically operated sensor could also be used to generate analyte specific response patterns. This approach is known as a virtual sensor array (VSA) and can exhibit significant advantages when compared to MSAs. Some …

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Coastal Ecosystem Resiliency After Major Disturbances, Giovanna Mcclenachan Jan 2016

Coastal Ecosystem Resiliency After Major Disturbances, Giovanna Mcclenachan

LSU Doctoral Dissertations

Disturbances are a common occurrence in coastal ecosystems and can provide opportunity for adaptation and renewal in healthy systems; hurricanes bring mineral accretion to a marsh, floods provide a pulse of freshwater and nutrients to estuaries, and fires increase species diversity and abundance in forests. Humans, however, have depleted the resiliency of many coastal systems via top down and bottom up mechanisms, leaving these ecosystems more vulnerable to both natural and anthropogenic disturbances. Louisiana’s wetlands have been modified for centuries via canals, levees, agricultural impoundments, etc., leading to a decreased resiliency to land loss. The Deepwater Horizon (DWH) oil spill …

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Peptidomimetic Polymers: Advances In Monomer Design And Polymerization Methods, Brandon Andrew Chan Jan 2016

Peptidomimetic Polymers: Advances In Monomer Design And Polymerization Methods, Brandon Andrew Chan

LSU Doctoral Dissertations

This work is focused on the design, synthesis and characterization of polypeptide and polypeptoid polymers. The former are composed of amino acid repeat units and possess intramolecular hydrogen bonding interactions allowing for the self-assembly into well-defined secondary structures (e.g. α-helix). Polypeptoids are based on N-alkyl substituted glycine and lack intramolecular hydrogen bonding interactions, resulting in enhanced proteolytic stability and thermal processability. Physicochemical properties of polypeptoids are strongly dependent on the side chain structures, allow for control of the solubility, crystallinity, and conformation of the polymers. Well-defined polypeptides and polypeptoids are synthesized by the ring-opening polymerization (ROP) of their corresponding N-carboxyanhydride …

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