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2006

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Articles 4741 - 4770 of 5872

Full-Text Articles in Physical Sciences and Mathematics

Synthesis Of Novel Antimycobacterials And A Fluorescent Sensor For Simple Carbohydrates, Brian Thomas Walker Jan 2006

Synthesis Of Novel Antimycobacterials And A Fluorescent Sensor For Simple Carbohydrates, Brian Thomas Walker

Theses and Dissertations

Cell surface carbohydrates play an important role in a wide variety of biological processes such as inflammation, tumor metastasis, and viral and bacterial infection. The goal of our research has been two-fold. The first objective was the synthesis of antimycobacterial compounds. A mannose containing tetrasaccharide from the mannan core of lipoarabinomannan (LAM) of Mycobacterium tuberculosis has been synthesized using α-D-methylmannopyranoside as starting material and Koeings-Knorr reactions to couple saccharides. The synthesis was completed in nine steps and in 14% total yield. This compound should be useful in competitive inhibition studies with macrophages or as an immunological marker. We have successfully …


Isolation Of Legionella Pneumophila From Well-Maintained Emergency Showers And Eyewash Stations, Jessica Mae Myers Jan 2006

Isolation Of Legionella Pneumophila From Well-Maintained Emergency Showers And Eyewash Stations, Jessica Mae Myers

Theses and Dissertations

Legionella pneumophila is a gram-negative bacterium responsible for Legionnaire's disease, and is commonly transmitted via aerosolized water. Legionella colonization of emergency eyewash and shower stations may pose an exposure hazard to users of these stations. There is little information about the role of these stations as significant reservoirs for Legionella. Samples were collected from 67 stations in an industrial facility. At the time of this study, the stations within this facility were under a routine maintenance program that included at least monthly flushing. This study also included the analysis for other bacterial organisms to determine an association between the presence …


Design And Analysis Methods For Cluster Randomized Trials With Pair-Matching On Baseline Outcome: Reduction Of Treatment Effect Variance, Misook Park Jan 2006

Design And Analysis Methods For Cluster Randomized Trials With Pair-Matching On Baseline Outcome: Reduction Of Treatment Effect Variance, Misook Park

Theses and Dissertations

Cluster randomized trials (CRT) are comparative studies designed to evaluate interventions where the unit of analysis and randomization is the cluster but the unit of observation is individuals within clusters. Typically such designs involve a limited number of clusters and thus the variation between clusters is left uncontrolled. Experimental designs and analysis strategies that minimize this variance are required. In this work we focus on the CRT with pre-post intervention measures. By incorporating the baseline measure into the analysis, we can effectively reduce the variance of the treatment effect. Well known methods such as adjustment for baseline as a covariate …


Determination Of The Band Gap Bowing Parameter Of A1xga1-Xn With Contactless Electroreflectance, Laura C. Mcglinchey Jan 2006

Determination Of The Band Gap Bowing Parameter Of A1xga1-Xn With Contactless Electroreflectance, Laura C. Mcglinchey

Theses and Dissertations

Contactless electroreflectance (CER), a modulation spectroscopy (MS) technique, has been used to study the A and C exciton transitions in A1xGa1-xN layers for a composition range of 0 ≤ x ≤ 0.48 at room temperature. Taking the entire composition range (0 ≤ x ≤ 1) into account by incorporating a previously reported band gap energy for AlN, the dependence of the A-exciton transition on composition showed a downward bowing from linearity. A bowing parameter of b = 1.7 eV was found. Analysis of the lower composition range 0 ≤ x ≤ 0.48 resulted in a linear fit, as did the …


Assessing, Modifying, And Combining Data Fields From The Virginia Office Of The Chief Medical Examiner (Ocme) Dataset And The Virginia Department Of Forensic Science (Dfs) Datasets In Order To Compare Concentrations Of Selected Drugs, Amy Elizabeth Herrin Jan 2006

Assessing, Modifying, And Combining Data Fields From The Virginia Office Of The Chief Medical Examiner (Ocme) Dataset And The Virginia Department Of Forensic Science (Dfs) Datasets In Order To Compare Concentrations Of Selected Drugs, Amy Elizabeth Herrin

Theses and Dissertations

The Medical Examiner of Virginia (ME) dataset and the Virginia Department of Forensic Science Driving Under the Influence of Drugs (DUI) datasets were used to determine whether people have the potential to develop tolerances to diphenhydramine, cocaine, oxycodone, hydrocodone, methadone, and morphine. These datasets included the years 2000-2004 and were used to compare the concentrations of these six drugs between people who died from a drug-related cause of death (of the drug of interest) and people who were pulled over for driving under the influence. Three drug pattern groups were created to divide each of the six drug-specific datasets in …


Exploration Of Iron And Cobalt Core-Shell Nanoparticles Via Thermal And Microwave Polyol Synthesis, Hope M. Klukovich Jan 2006

Exploration Of Iron And Cobalt Core-Shell Nanoparticles Via Thermal And Microwave Polyol Synthesis, Hope M. Klukovich

Browse all Theses and Dissertations

Thermal and microwave polyol methods were investigated in the synthesis of various iron and cobalt core-shell nanoparticles. The reaction involved 1 mmol of an Fe+2 or Co+2 salt, bis-acetylacetanato [(Acac)2] iron (II), cobalt (Acac)2 or iron (II) acetate along with 1 mmol of a surfactant capping agent. The salt was reduced with 2 mmol of a 1,2 diol. When 1,2-hexadecanediol solid was used as a reducing agent, it was dissolved along with the metal salt and capping agent in octyl ether. When 1,2-hexanediol liquid was used as the reducing agent, it was also the solvent, and octyl ether …


Feasibility Analysis Of The Strontium Ratio Obtained From Pennsylvanian Chondricthian Dentary, Cullen John Erbacher Jan 2006

Feasibility Analysis Of The Strontium Ratio Obtained From Pennsylvanian Chondricthian Dentary, Cullen John Erbacher

Browse all Theses and Dissertations

This research was undertaken to determine the amount of time between transgressive and regressive sequences. One of the methods used to determine the amount of missing time in an unconformity is the 87Sr / 86Sr ratio. The 87Sr / 86Sr ratio will be high around brackish and freshwater environments while it will be lower in open marine conditions. Limestones and their constituent parts are susceptible to diagenetic processes that can contaminate or obliterate isotope values contained within the rocks. The purpose of this research was to discover if reliable isotope information could be pulled from Pennsylvanian aged shark teeth. Nine …


Pyrrole Carboxamides As Potential Carbonic Anhydrase Inhibitors, Nishrin Ismailbhai Marketwala Jan 2006

Pyrrole Carboxamides As Potential Carbonic Anhydrase Inhibitors, Nishrin Ismailbhai Marketwala

Browse all Theses and Dissertations

Carbonic anhydrases (CAs) are metalloenzymes that catalyze the reversible interconversion of CO2 and bicarbonate. We recently initiated a screen of a broad range of indoles and pyrroles possessing acyl-, carboxyl-, amido-, sulfonyl-, sulfamyl- and oxime- functionalities as potential inhibitors of á-CA II isozyme. As slight inhibition was observed in the case of 2-carboxamido-1-(phenylsulfonyl)pyrrole, and aware that pyrrole carboxamide derived sulfonamides had been previously demonstrated to possess CA inhibition, we sought to prepare a series of 1-(phenylsulfonyl)pyrrole-2-carboxamides but lacking a sulfonamide moiety to ascertain if the activity in our case might be due to a hitherto unrecognized pyrrole pharmacophore. To this …


The Modeling Of Solubility, Frank Christopher Campanell Jan 2006

The Modeling Of Solubility, Frank Christopher Campanell

Browse all Theses and Dissertations

In this work the solubilities of gases in liquids and liquids in liquids were modeled using both physical properties and topological descriptors of the solutes. Quantitative structure-activity relationship (QSAR) methods were employed to create single-linear regression (SLR) and multiple-linear regression (MLR) models of the solubilities. Factor analysis was employed to determine the number of significant factors present in the solubilities. The solubilities of monoalcohols in water, halogenated alkanes in water, gases in water, gases in alkanes, and gases in alcohols were examined and modeled.


Electron Shock Waves, Mostafa Hemmati, Michael Weller, Taylor Duncan Jan 2006

Electron Shock Waves, Mostafa Hemmati, Michael Weller, Taylor Duncan

Journal of the Arkansas Academy of Science

In this paper we describe numerical investigations of breakdown waves concentrating on antiforce waves. We employed one-dimensional electron fluid dynamical equations for a luminous pulse wave propagating into a neutral gas region and subjected to an applied electric field. We assumed that the electrons were the main element in the propagation of the wave and that the electron gas partial pressure provided the driving force. These waves are considered to be shock fronted and are composed of two regions: the thin sheath region behind the shock front and the thicker quasi-neutral region following the sheath region. Our set of equations, …


Index Future Pricing Under Imperfect Market And Stochastic Volatility, Wei-Hsien Li Jan 2006

Index Future Pricing Under Imperfect Market And Stochastic Volatility, Wei-Hsien Li

LSU Master's Theses

Financial markets in emerging countries are volatile and imperfect, so pricing model under traditional perfect-market frameset may not give reliable price of financial derivatives. The most famous pricing model for stock index future is the cost of carry model. The mis-pricing of cost of carry model inspires lots of following researches. Even transaction costs, dividends, stochastic interest rate, stochastic volatility, market imperfection, and other factors are considered, we still do not obtain a model price consistently better than cost of carry model. But these researches offer important insights, for example, the market needs time to mature and the more complex …


Study Of Reliable Data Communication In Wireless Sensor Networks, Ravilochan Shamanna Jan 2006

Study Of Reliable Data Communication In Wireless Sensor Networks, Ravilochan Shamanna

LSU Master's Theses

A distributed wireless sensor network consists of numerous tiny autonomous sensing nodes deployed across a wide geographical area. These sensor nodes self organize and establish radio communication links with the neighboring nodes to form multi-hop routing paths to the central base station. The dynamic and lossy nature of wireless communication poses several challenges in reliable transfer of data from the sensor nodes to the sink. There are several applications of sensor networks wherein the data collected by the sensors in the network are critical and hence have to be reliably transported to the sink. An example of such an application …


Two-Dimensional Penalized Signal Regression For Hand Written Digit Recognition, Qing Tang Jan 2006

Two-Dimensional Penalized Signal Regression For Hand Written Digit Recognition, Qing Tang

LSU Master's Theses

Many attempts have been made to achieve successful recognition of handwritten digits. We report our results of using statistical method on handwritten digit recognition. A digitized handwritten numeral can be represented by an image with grayscales. The image includes features that are mapped into two-dimensional space with row and column coordinates. Based on this structure, two-dimensional penalized signal logistic regression (PSR) is applied to the recognition of handwritten digits. The data set is taken from the USPS zip code database that contains 7219 training images and 2007 test images. All the images have been deslanted and normalized into 16 x …


Resource Recovery Of Coal Bed Methane Formation Water, Catherine Elizabeth Bishop Jan 2006

Resource Recovery Of Coal Bed Methane Formation Water, Catherine Elizabeth Bishop

LSU Master's Theses

During the excavation of natural gas, petroleum hydrocarbon-polluted brine water, termed production water, is drawn from the coal bed methane formations (CBMF) along with the natural gas product. The water is drawn out in vast amounts and re-injected into the CBMF. In the Greater Rocky Mountain Region (GRMR) where water supplies are dwindling, the remediation of CBMF production water has become a high priority for maintaining agriculture, residential development and industrial expansion. The overall objective of this research was to demonstrate in laboratory and field pilot studies the efficacious merging of Immobilized Microbe BioReactor (IMBR) technologies for biodegradation/mineralization of organics …


Implementation Of Labcreator And The Integration Of Cyberlab, Kang Zhao Jan 2006

Implementation Of Labcreator And The Integration Of Cyberlab, Kang Zhao

Master's Theses and Doctoral Dissertations

With the development of the World Wide Web, online courses are becoming more and more popular in modern science education. CyberLab aims to solve an important issue in distance science education -- laboratory experiments in online courses. It is a toolkit that handles creation, exportation, and execution of virtual experiments (within web browsers). It consists of LabCreator and LabExecutor. With LabCreator, instructors can create virtual experiments and export them into intermediate files. Students can download those files from online course websites and execute them in LabExecutor on their own computers.

The paper reports on the completion of two important tasks …


Segmental Dynamics Of Poly(Isopropyl Acrylate)-D7 On Silica, Piyawan Krisanangkura, Frank D. Blum Jan 2006

Segmental Dynamics Of Poly(Isopropyl Acrylate)-D7 On Silica, Piyawan Krisanangkura, Frank D. Blum

Chemistry Faculty Research & Creative Works

For a polymer film deposited on a surface, the strength of the surfacesegment interaction affects the mobility of polymer-chain segments. The selfconsistent field lattice model of Scheutjens and Fleer,1 based on mean-field lattice models of polymer at interfaces,2 has been used to describe the distribution of conformations of polymers on surfaces. Adsorbed-polymer segments may be classified as belonging to loops, trains or tails. There are different techniques used to study the molecular motion of the polymer including modulated differential scanning calorimetry (MDSC)3 and nuclear magnetic resonance (NMR).4,5 in this work, solid-state deuterium (2H) NMR was used to characterize the polymer …


Synthesis And Thermal Behavior Of Poly(Methyl Acrylate) Attached To Silica By Surface-Initiated Atrp, Manikantan B. Nair, Frank D. Blum Jan 2006

Synthesis And Thermal Behavior Of Poly(Methyl Acrylate) Attached To Silica By Surface-Initiated Atrp, Manikantan B. Nair, Frank D. Blum

Chemistry Faculty Research & Creative Works

The modification of the surface of an object dictates the response of the object to an external environment.1 Surface-modified materials and nanoparticles have attracted immense interest due to the various desirable electronic, optical and magnetic properties they possess.2 Silica is widely used as an inorganic filler. Surface modification of the silica, with a variety of organic moieties, facilitates the utilization of silica in conjunction with organic systems. The resulting organic/inorganic hybrid materials have significant potential applications. This work reports the synthesis and characterization of modified silica, and poly(methyl acrylate) attached to the modified silica. An observation of the thermal behavior …


New Orleans, The Chesapeake, And The Future Of Environmental Assessment: Overcoming The Natural Resources Law Of Unintended Consequences, Erin Ryan Jan 2006

New Orleans, The Chesapeake, And The Future Of Environmental Assessment: Overcoming The Natural Resources Law Of Unintended Consequences, Erin Ryan

Faculty Publications

No abstract provided.


Computer-Aided Diagnostic Systems For Digital Mammograms, Nicholas Jabari Lee Jan 2006

Computer-Aided Diagnostic Systems For Digital Mammograms, Nicholas Jabari Lee

LSU Master's Theses

A computer-aided diagnostic (CAD) system that uses a unique shape-based classification scheme, the Ellipse-Closed Curve Fitting (ECCF) algorithm, is developed for digital mammogram image analysis. The system is developed to work as a post-processing extension to a previously developed CAD system that locates and segments mass lesions, or tumors, found in digital mammograms into separate images. The ECCF system is implemented in the MATLAB mathematical scripting language and is thus capable of running on multiple platforms. The ECCF algorithm detects edges in tumor images and casts them into closed curve functions. Parameters for an ellipse of best fit for a …


Swamp Tours In Louisiana Post Hurricane Katrina And Hurricane Rita, Dawn Schaffer Jan 2006

Swamp Tours In Louisiana Post Hurricane Katrina And Hurricane Rita, Dawn Schaffer

LSU Master's Theses

Hurricanes Katrina and Rita made landfall in southern Louisiana during August and September 2005, respectively. Prior to these storms swamp tours were a popular nature-based tourism experience that entertained visitors while teaching them about local flora, fauna, and culture. The number of swamp tour businesses in the state was slowly increasing. The purpose of this study was to determine how many swamp tours were operating after the hurricanes, what type of damage they sustained, and how they repaired their businesses. Differences between those tours that remained open after the hurricanes and those that closed were also examined. A 3-phase mail …


Study Of Reliable Data Communication In Wireless Sensor Networks, Ravilochan G. Shamanna Jan 2006

Study Of Reliable Data Communication In Wireless Sensor Networks, Ravilochan G. Shamanna

LSU Master's Theses

A distributed wireless sensor network consists of numerous tiny autonomous sensing nodes deployed across a wide geographical area. These sensor nodes self organize and establish radio communication links with the neighboring nodes to form multi-hop routing paths to the central base station. The dynamic and lossy nature of wireless communication poses several challenges in reliable transfer of data from the sensor nodes to the sink. There are several applications of sensor networks wherein the data collected by the sensors in the network are critical and hence have to be reliably transported to the sink. An example of such an application …


Effects Of Silvicultural Techniques And Landscape Management On Habitat Quality And Relative Abundance For Northern Bobwhites In A Pine Plantation Forest, Jason Douglas Burke Jan 2006

Effects Of Silvicultural Techniques And Landscape Management On Habitat Quality And Relative Abundance For Northern Bobwhites In A Pine Plantation Forest, Jason Douglas Burke

LSU Master's Theses

Pine plantation forests are increasing in scope across the southeastern United States, particularly Louisiana. These areas provide poor quality bobwhite brood-rearing habitats, and become increasingly degraded without periodic disturbance. Poor quality habitat conditions at a landscape-level scale usually results in reduced fall bobwhite body weights, creating low survival rates. We researched 4 understory vegetation management techniques (ie. mowing, no treatment, burn only, and imazapyr with burning) within pine plantations to evaluate their effects on vegetation composition and structure and on arthropod abundance and availability relative to bobwhite brooding habitat in 2002-2005. We used 1,155 human-imprinted bobwhite chicks to estimate foraging …


U.S. Demand For Certified Tropical Hardwood Products, Shadia Duery Jan 2006

U.S. Demand For Certified Tropical Hardwood Products, Shadia Duery

LSU Master's Theses

Tropical forests, which contain 50 percent of the planet's biodiversity, are threatened by deforestation and illegal logging. Forest certification was initiated initially as a s certification: forest management practices and chain of custody (CoC). The United States is the largest market for secondary, or value-added, tropical hardwood products (STHP) which influences forest management practices in supplier countries. In 2004, this study was conducted to measure the demand for certified products in the U.S. The objectives of the study were to identify characteristics of U.S. demand for secondary (value-added) tropical hardwood products and to understand market perceptions regarding certification of secondary …


Mcd And Magnetization Studies On Nifb/Nifz Minus Molybdenum Iron Protein From Azotobacter Vinelandii, Marcia S. Cotton Jan 2006

Mcd And Magnetization Studies On Nifb/Nifz Minus Molybdenum Iron Protein From Azotobacter Vinelandii, Marcia S. Cotton

LSU Master's Theses

This study reports a characterization of the iron-sulfur clusters of the MoFe protein expressed by the nifBnifZ deletion strain of A. vinelandii. VT-MCD spectroscopic and magnetization analysis of as-isolated ΔnifBΔnifZ MoFe protein were undertaken. VT-MCD spectra of as-isolated ΔnifBΔnifZ MoFe protein contains bands remarkably similar to those seen in as-isolated ΔnifH MoFe protein, assigned to arise from an [4Fe-4S]+ cluster. The low-temperature magnetization curve of as-isolated ΔnifBΔnifZ MoFe protein reveals the MCD spectra bands stem from an S = ½ spin system with diamagnetic contributions of some other species. As-isolated ΔnifBΔnifZ MoFe protein is compared with as-isolated ΔnifH MoFe …


Laboratory And Field Measurements Of Bioturbation By Macrofauna In A Coastal Setting, Skyler Neylon Jan 2006

Laboratory And Field Measurements Of Bioturbation By Macrofauna In A Coastal Setting, Skyler Neylon

LSU Master's Theses

Two ophiuroid species, Hemipholis elongata and Ophiophragmus spp. were studied in laboratory microcosms to elucidate patterns of sediment mixing for key bioturbators in the Mississippi Sound, Mississippi. The effects of bioturbation on artificially stratified sediments in microcosms were traced via time-series digital x-radiography. Preliminary results indicate that for three population densities of the brittle stars (comparable to field densities), a steady state volumetric bioturbation rate of 1-2 cm3/d is reached within two months of introduction to a fresh system. The preservation quotient, q, a fractional measure of preserved primary fabric, reached a minimum of 0.5 during the 16-week experiment. Maximum …


Breeding Waterbird Use Of Rice Fields In Southwestern Louisiana, Sergio Pierluissi Jan 2006

Breeding Waterbird Use Of Rice Fields In Southwestern Louisiana, Sergio Pierluissi

LSU Master's Theses

Rice fields are agricultural wetlands concentrated in several areas in the U.S., including southwestern Louisiana. Rice fields are flooded for much of the year and support thick emergent vegetation, potentially providing high-quality habitat for several species of breeding waterbirds. The objectives of this study were to (1) determine relative nest density, nest success, and habitat associations of breeding waterbirds in southwestern Louisiana rice fields and (2) determine the effectiveness of callback surveys as a monitoring tool. In the summers of 2004 and 2005, marsh bird surveys and nest searches were conducted in Cameron, Jefferson Davis, Vermilion, and Acadia Parishes in …


Using Elimination To Describe Maxwell Curves, Lucas P. Beverlin Jan 2006

Using Elimination To Describe Maxwell Curves, Lucas P. Beverlin

LSU Master's Theses

Cartesian ovals are curves in the plane that have been studied for hundreds of years. A Cartesian oval is the set of points whose distances from two fixed points called foci satisfy the property that a linear combination of these distances is a fixed constant. These ovals are a special case of what we call Maxwell curves. A Maxwell curve is the set of points with the property that a specific weighted sum of the distances to n foci is constant. We shall describe these curves geometrically. We will then examine Maxwell curves with two foci and a special case …


Security In Heterogeneous Wireless Networks, Vijay Bulusu Jan 2006

Security In Heterogeneous Wireless Networks, Vijay Bulusu

LSU Master's Theses

The proliferation of a range of wireless devices, from the cheap low power resource starved sensor nodes to the ubiquitous cell phones and PDA's has resulted in their use in many applications. Due to their inherent broadcast nature Security and Privacy in wireless networks is harder than the wired networks. Along with the traditional security requirements like confidentiality, integrity and non-repudiation new requirements like privacy and anonymity are important in wireless networks. These factors combined with the fact that nodes in a wireless network may have different resource availabilities and trust levels makes security in wireless networks extremely challenging. The …


Characterization Of The Dependency Across Foreign Exchange Markets Using Copulas, Ryan Coelho Jan 2006

Characterization Of The Dependency Across Foreign Exchange Markets Using Copulas, Ryan Coelho

LSU Master's Theses

Though Pearson's correlation coefficient provides a convenient approach to measuring the dependency between two variables, in the last few years, there has been a significant amount of literature cautioning against the use of Pearson's correlation coefficient, as it does not remain invariant under monotone transformations of the underlying distribution functions. Since we are interested in examining the dependency pattern observed by the return on the Sterling Pound with that of the Japanese Yen, we will use the notion of a copula to approximate the joint density function between the daily returns on the Sterling Pound and the Japanese Yen. In …


Salt Marsh Restoration With Sediment-Slurry Amendments Following A Drought-Induced, Large-Scale Disturbance, Angela Marie Schrift Jan 2006

Salt Marsh Restoration With Sediment-Slurry Amendments Following A Drought-Induced, Large-Scale Disturbance, Angela Marie Schrift

LSU Master's Theses

A large-scale, drought-induced disturbance occurred in Louisiana during the spring and summer of 2000. Approximately 100,000 acres of Spartina dominated marshes died-back and turned brown. This die-off caused considerable concern because in the absence of recovery dieback marshes can transform to mudflats, which can subside leading to open ponds. The state of Louisiana is attempting to restore some of the dieback marshes through the addition of sediment-slurries. The sediment-slurry generated significantly different marsh elevations: high elevation (mean and 95 % confidence interval: 29, 26 to 32 cm above ambient marsh), medium elevation (21, 19 to 24 cm), low elevation (14, …