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Articles 1 - 30 of 75
Full-Text Articles in Physical Sciences and Mathematics
Global Patterns Of Dissolved N, P And Si In Large Rivers, R. Eugene Turner, Nancy N. Rabalais, D. Justic', Q. Dortch
Global Patterns Of Dissolved N, P And Si In Large Rivers, R. Eugene Turner, Nancy N. Rabalais, D. Justic', Q. Dortch
Faculty Publications
The concentration of dissolved inorganic nitrogen (DIN), dissolved nitrate-N, Total-N (TN), dissolved inorganic phosphate (DIP), total phosphorus (TP), dissolved silicate-Si (DSi) and their ratios in the world's largest rivers are examined using a global data base that includes 37% of the earth's watershed area and half its population. These data were compared to water quality in 42 subbasins of the relatively well-monitored Mississippi River basin (MRB) and of 82 small watersheds of the United States. The average total nitrogen concentration varies over three orders of magnitude among both world river watersheds and the MRB, and is primarily dependent on variations …
Valuation Of Continuous And Intermittent Phragmites Control, R. Eugene Turner, R. S. Warren
Valuation Of Continuous And Intermittent Phragmites Control, R. Eugene Turner, R. S. Warren
Faculty Publications
Quantifying the relative value of Phragmites australis and Spartina alterniflora habitat is important to evaluate the benefits and risks of different attempts to address Phragmites expansion on the U.S. eastern seaboard. Two contrasting approaches commonly used to restore tidal marsh habitats invaded by Phragmites communities involve spraying Phragmites with herbicide only when its coverage of a particular marsh area is near or close to 100%. Alternatively, after the first application, herbicide is annually applied on any surviving patches of Phragmites present in a mosaic of other marsh vegetation. A model is introduced to evaluate the relative habitat value of these …
Review Of The Final Frontier, Michael F. Russo
Review Of The Final Frontier, Michael F. Russo
Faculty Publications
No abstract provided.
Climatic Influences On Riverine Nitrate Flux: Implications For Coastal Marine Eutrophication And Hypoxia, Dubravko Justic, R. Eugene Turner, Nancy N. Rabalais
Climatic Influences On Riverine Nitrate Flux: Implications For Coastal Marine Eutrophication And Hypoxia, Dubravko Justic, R. Eugene Turner, Nancy N. Rabalais
Faculty Publications
The average nitrate flux of the lower Mississippi River increased 3.3-fold between 1954–1967 and 1983–2000. During the same time period, the average nitrate concentration increased 2.3-fold while the average discharge increased 40%. Partitioning of the observed trend in nitrate flux among the two flux components, nitrate concentration and discharge, revealed that about 80% of the observed increase in flux could be explained by the increase in nitrate concentration. This indicates that a historical increase in the anthropogenic nutrient inputs has had a far greater impact on the lower Mississippi River nitrate flux than a change in climate. The influence of …
Abundance Trends And Environmental Habitat Usage Patterns Of Bottlenose Dolphins (Tursiops Truncatus) In Lower Barataria And Caminada Bays, Louisiana, Cara Edina Miller
Abundance Trends And Environmental Habitat Usage Patterns Of Bottlenose Dolphins (Tursiops Truncatus) In Lower Barataria And Caminada Bays, Louisiana, Cara Edina Miller
LSU Doctoral Dissertations
The paucity of research into the environmental requirements, stock membership, abundance and residency patterns of bottlenose dolphins (Tursiops truncatus) in coastal Louisiana creates difficulty in understanding how local ecosystems and threats (such as fishery interactions, habitat degradation and pollution) affect populations. This study combined fine-scale environmental measurements and photo-identification techniques to describe patterns of habitat usage and abundance of bottlenose dolphins in lower Barataria Basin from June 1999 to May 2002. In addition I investigated the validity and limitations of using mark-recapture models to estimate abundance from cetacean photo-identification data. Bottlenose dolphins were present year-round in a wide range of …
Pulsed River Flooding Effects On Sediment Deposition In Breton Sound Estuary, Louisiana, Katherine Wheelock
Pulsed River Flooding Effects On Sediment Deposition In Breton Sound Estuary, Louisiana, Katherine Wheelock
LSU Master's Theses
Louisiana's deltaic coast is a dynamic sedimentary environment made vulnerable by Mississippi River channelization, which restricts freshwater, sediment, and nutrient inputs to adjacent estuaries. Freshwater diversions now reconnect some estuaries with historic fluvial sources, like Breton Sound basin, which receives Mississippi River suspended loads through the Caernarvon freshwater diversion. The project objectives were to quantify short-term sediment accumulation using sediment traps, evaluate sediment trap effectiveness, and compare long-term deposition using feldspar horizon markers and 210Pb dating to the annual sediment trap deposition. Magnitude and variations of sediment deposition at 14 sites were compared during an 18-month study in the upper …
Factors Affecting Participation In City Recycling Programs, Stacy Marie Lockhart
Factors Affecting Participation In City Recycling Programs, Stacy Marie Lockhart
LSU Master's Theses
Recycling consists of diverting or recovering materials from the solid waste stream that would otherwise end up returning to the environment as a potential source of pollution. These collected materials are then used as raw materials in the manufacture or assembly of a new product or package. Over the years the amount of municipal solid waste being generated per person has steadily increased. Waste disposal costs are also increasing, making recycling even more important. To address this issue cities are developing recycling policies or plans. The type of plan varies according to the area; as of this time there are …
A Stellar Parameter Calibration Of Iue Data For The Determination Of The Present Day Mass Function Of High Mass Stars, Kenneth Thomas Taylor
A Stellar Parameter Calibration Of Iue Data For The Determination Of The Present Day Mass Function Of High Mass Stars, Kenneth Thomas Taylor
LSU Master's Theses
A study of stellar atmosphere models and the photometric quantity R is presented here, with R being the ratio of the integrated de-reddened fluxes from the two wavelength regions of the International Ultraviolet Explorer (IUE) satellite cameras. The effective temperatures and surface gravities of the stellar atmospheres were calibrated against R and absolute magnitude, using stellar evolution tracks from the literature, and applied to over 156 LMC stars whose masses and mass function are then derived from the results. The results show that the effective temperatures and surface gravities of stars derived from R and absolute magnitude correlate well with …
Using Functional Distance Measures When Calibrating Journey-To-Crime Distance Decay Algorithms, Joshua David Kent
Using Functional Distance Measures When Calibrating Journey-To-Crime Distance Decay Algorithms, Joshua David Kent
LSU Master's Theses
Spatial analysis has long been a valuable tool used within the criminal investigative process. This is especially true for serial offence cases where criminologists apply geographic profiling to model offender mobility and crime distribution patterns in order to estimate a criminal’s likely residence. Yet, traditional analytical methodologies have avoided the utilization of functional distance measures when modeling an offender’s journey-to-crime within an anisotropic landscape. By substituting straight-line Euclidean distances with travel path functional distance measures, the predictive utility and technological prerequisites associated with geographically profiling a localized serial offender was assessed using mathematically calibrated distance decay models. Both the travel-path …
Splitter Theorems For 3- And 4-Regular Graphs, Jinko Kanno
Splitter Theorems For 3- And 4-Regular Graphs, Jinko Kanno
LSU Doctoral Dissertations
Let g be a class of graphs and ≤ be a graph containment relation. A splitter theorem for g under ≤ is a result that claims the existence of a set O of graph operations such that if G and H are in g and H≤G with G≠H, then there is a decreasing sequence of graphs from G to H, say G=G0≥G1≥G2...Gt=H, all intermediate graphs are in g, and each Gi can be obtained from Gi-1 by applying a single …
Black Willow (Salix Nigra) Use In Phytoremediation Techniques To Remove The Herbicide Bentazon From Shallow Groundwater, Robert Mark Conger
Black Willow (Salix Nigra) Use In Phytoremediation Techniques To Remove The Herbicide Bentazon From Shallow Groundwater, Robert Mark Conger
LSU Doctoral Dissertations
Wetland environments have been impacted by the activities of man over the past several hundred years in North America. Industrialization into wetland areas has brought with it anthropogenic compounds that have been released into soils and groundwater. The use of phytoremediation to detoxify soil and groundwater began in the mid 1990's and has become a popular remediation technology. In 1994, a feasibility study for using phytoremediation in such an industrialized wetland area was conducted at a petrochemical facility at BASF Corporation, located about 20 kilometers south of Baton Rouge, Louisiana in Ascension Parish. The test site consisted of low level …
Development And Implementation Of Fine Structure Aerosol Spectrum Coagulation Kernels And Deposition Mechanisms Using Advanced Nodal Method In The Caerot Code, Hyeongkae Park
LSU Master's Theses
Aerosol transport in confined spaces was studied via numerical simulation using the dynamic aerosol equation, which is Boltzmann?s transport equation at the hydrodynamic limit. Until recent years, there existed no comprehensive computational tool to predict the spatial distribution and time evolution of aerosol size spectrum. A previously developed code, INDASOL3D, solves the dynamic aerosol equation by using a homogenized control-volume based finite difference method applying the group sectional method on the coagulation dynamics. However, quantitative correctness has not been satisfactory. In this thesis, two new codes (SAEROSA, and CAEROT) were developed. SAEROSA computes the time evolution of the size spectrum …
Effect Of Temperature On Efficiency Of In Situ Bioremediation Technology: A Laboratory Microcosm And Field Study, Javed Iqbal
Effect Of Temperature On Efficiency Of In Situ Bioremediation Technology: A Laboratory Microcosm And Field Study, Javed Iqbal
LSU Master's Theses
Laboratory microcosm experiment and parallel ex situ bioremediation studies were conducted to study the effect of temperature on in situ bioremediation systems installed at Superfund site in southeast Georgia. Laboratory microcosms, inoculated with PAHs/phenols specific microorganisms, at high temperatures (42±2°C; 107±3°F) demonstrated a significant reduction of residual polycyclic aromatic hydrocarbons (PAHs) and selected phenols from 4927±1356ng/g dry weight soil to 1158±530ng/g with a kinetic rate of 76.1±16.8ng/g/day (84% reduction; p≤0.01) in 49days. High temperature non-inoculated microcosms were reduced of residual PAHs and phenols from 1117±436ng/g to 341±116ng/g with a kinetic rate of 15.8±6.5ng/g/day (65% reduction; p≤0.01) in 49days. Low temperature …
Low Salinity Waters In Deep Sedimentary Basins, David Scott Szalkowski
Low Salinity Waters In Deep Sedimentary Basins, David Scott Szalkowski
LSU Master's Theses
While the composition and origin of brines in deep sedimentary basins has been extensively discussed, the composition and origin of low salinity waters is not as well documented. Since the 1960s, the presence of deep, low-salinity waters has been observed in some sedimentary basins and is commonly present in overpressured sections. The episodic release of low salinity, overpressured fluids upward into sediments containing high salinity formation waters likely occurs at <100-year intervals. Because there is a growing body of evidence that suggests mixing formation waters of varying salinity could induce the dissolution and precipitation of minerals, it is important to have detailed information about chemical compositions of both end-member fluids to adequately predict such mixing results. This study concludes that low salinity waters (<35 g/l) are generally not unique in major solute composition when compared to high salinity waters (>35 g/l). On log-log plots, monovalent cations plot along 1:1 slopes with respect to salinity and total anionic charge, while divalent cations plot along 2:1 slopes. However, this study concludes …
Computer Assisted Eye Fungal Infection Diagnosis, Madhusudhanan Balasubramanian
Computer Assisted Eye Fungal Infection Diagnosis, Madhusudhanan Balasubramanian
LSU Master's Theses
In this thesis, an attempt has been made to assist the diagnosis of Fungal Keratitis, a fungal infection that occurs in the corneal layers of the eye, by identifying the region of infection in the corneal images using fractal-based features. Three features related to the fractal dimension of the surface of the image, when represented in a 3D using the pixel intensity measure, are used to identify these regions in the image. To reduce the computation complexity, Fisher linear discriminant (FLD) is used to reduce the 3D raw feature to 1D feature, while preserving feature values. Using the adaptive mixtures …
Gauss' Method Of Least Squares: An Historically-Based Introduction, Belinda B. Brand
Gauss' Method Of Least Squares: An Historically-Based Introduction, Belinda B. Brand
LSU Master's Theses
This work presents Gauss' justification of the method of least squares, following the treatment given by Gauss himself in "Theoria Combinationis Observationum Erroribus Minimis Obnoxiae," where the main idea is to show that the least squares estimate is the unbiased linear estimate of minimum variance. (Actually, we present Gauss' argument both in his terminology and translated into matrix terminology.) We show how this contrasts with Gauss' earlier justfication in "Theoria Motus Corporum Coelestium" which was based on the assumption of a normal distribution of errors, and yielded the estimate of maximum likelihood. We present as a background the development from …
A Risk-Averse Strategy For Blackjack Using Fractional Dynamic Programming, Ryan A. Dutsch
A Risk-Averse Strategy For Blackjack Using Fractional Dynamic Programming, Ryan A. Dutsch
LSU Master's Theses
We present how blackjack is related to a discrete-time control problem, rather than a zero-sum game. Using the compiler Visual C++, we write a program for a strategy for blackjack, but instead of maximizing the expected value, we use a risk-averse approach. We briefly describe how this risk-averse strategy is solved by using a special type of dynamic programming called fractional dynamic programming.
Correlation Of Core Characteristics To Outcrop Upper Jackfork Group Turbidites, Degray Lake, Arkansas, Daniel James Golob
Correlation Of Core Characteristics To Outcrop Upper Jackfork Group Turbidites, Degray Lake, Arkansas, Daniel James Golob
LSU Master's Theses
Pennsylvanian age Jackfork Group cores from the DeGray Lake Dam and outcrop from the east wall of the DeGray Lake Spillway, Arkansas, provide an opportunity for a detailed study on the transport and depositional characteristics of a fine-grained, deep-water depositional system. Two phases of resedimentation processes are responsible for deposition of the sediments in the cores and the outcrop. Primary resedimentation processes transport terrigenous sediments from the shelf or basin edge into the middle fan environment, while secondary resedimentation alter the sediments after they are initially deposited in the environment. Debris flows, slurry flows, and high and low density turbidity …
The Use Of The Bang-3 Polymer Gel To Quantify The Three-Dimensional Dose Distribution Of Imrt, Paul Anthony Bruce
The Use Of The Bang-3 Polymer Gel To Quantify The Three-Dimensional Dose Distribution Of Imrt, Paul Anthony Bruce
LSU Master's Theses
The sophistication of radiation therapy delivery techniques at Mary Bird Perkins Cancer Center (MBPCC) creates the need for an advanced dosimetric system that can quantify and verify the dose distributions in three-dimensions. Current dosimetric systems perform this dose analysis in only one or two dimensions. This paper evaluates the application of BANG-3™ polymer gel dosimetry to quantify the 3-D dose distribution of Intensity-Modulated Radiation Therapy (IMRT) using a "step and shoot" approach. The gel was irradiated by 10 MV photons at a dose rate of 400 MU/min. Relaxation rate maps were computed from proton density and T2-weighted magnetic …
Stock Price Modeling And Insider Trading Theory, Jessica J. Guillory
Stock Price Modeling And Insider Trading Theory, Jessica J. Guillory
LSU Master's Theses
The mathematical study of stock price modeling using Brownian motion and stochastic calculus is a relatively new field. The randomness of financial markets, geometric brownian motions, martingale theory, Ito's lemma, enlarged filtrations, and Girsanov's theorem provided the motivation for a simple characterization of the concepts of stock price modeling. This work presents the theory of stochastic calculus and its use in the financial market. The problems on which we focus are the models of an investor's portfolio of stocks with and without the possibility of insider trading, opportunities for fair pricing of an option, enlarged filtrations, consumptions, and admissibility. This …
Regional Water Quality Models For The Prediction Of Eutrophication Endpoints, Anindita Das
Regional Water Quality Models For The Prediction Of Eutrophication Endpoints, Anindita Das
LSU Master's Theses
Eutrophication is a process by which a waterbody progresses from its origin to its extinction. During this period, there is a gradual accumulation of nutrients and organic biomass, accompanied by a decrease in average depth of the water due to sediment accumulation, and an increase in primary productivity, usually in the form of dense algal blooms. Cultural eutrophication occurs when humans, through their various activities, greatly accelerate this process. Eutrophication can cause loss in species diversity, fish kills, and decrease the aesthetic value of a waterbody. The EPA is trying to prevent cultural eutrophication by setting standards for water quality …
Scalable Parallel Molecular Dynamics Algorithms For Organic Systems, Satyavani Vemparala
Scalable Parallel Molecular Dynamics Algorithms For Organic Systems, Satyavani Vemparala
LSU Master's Theses
A scalable parallel algorithm, Macro-Molecular Dynamics (MMD), has been developed for large-scale molecular dynamics simulations of organic macromolecules, based on space-time multi-resolution techniques and dynamic management of distributed lists. The algorithm also includes the calculation of long range forces using Fast Multipole Method (FMM). FMM is based on the octree data structure, in which each parent cell is divided into 8 child cells and this division continues until the cell size is equal to the non-bonded interaction cutoff length. Due to constant number of operations performed at each stage of the octree, the FMM algorithm scales as O(N). Design and …
Multileaf Collimator Positional Reproducibility Evaluated With A Two-Dimensional Diode Array, Kara King Ferachi
Multileaf Collimator Positional Reproducibility Evaluated With A Two-Dimensional Diode Array, Kara King Ferachi
LSU Master's Theses
When delivering the total dose via a sequence of small fields shaped by a multileaf collimator, it is important to consider leaf positional reproducibility. A small error in the leaf position can result in large dose errors to the entire field. This is true for both dynamic multileaf collimation and step and shoot delivery. The goal of this research project is to design a method of quality assurance that is easily reproducible, sensitive to small changes in leaf position, and requires minimal time on the part of the medical physicist to carry out. This paper describes a system of measurements …
Field Validation Of Bentazon Phytoremediation, Sajida Begum
Field Validation Of Bentazon Phytoremediation, Sajida Begum
LSU Master's Theses
Phytoremediation with black willow (Salix nigra) was conducted in 1996 by planting trees at a density of 2000 trees/hectare at BASF Corporation in a shallow groundwater plume containing low levels of bentazon. In this project, the roots, stems,and leaves of the black willow plants were extracted and analyzed to see if bentazon from the ground water was taken up by the plants. Different extraction procedures such as liquid-phase extraction and solid-phase extraction were compared. Final determination using different analytical techniques such as GC-MSD, GC-ECD, and HPLC with UV detection for the isolation and analysis of bentazon residues from the plant …
Compositional Systematics Of Deep, Low Salinity Formation Waters In The Upper Wilcox Of Southeastern Texas, Kathleen (Kt) Moran
Compositional Systematics Of Deep, Low Salinity Formation Waters In The Upper Wilcox Of Southeastern Texas, Kathleen (Kt) Moran
LSU Master's Theses
Overpressured Eocene Wilcox sandstones in the Newton County, Texas Sabine Tram field contain water with salinities ranging from 14 to 28 g/L. The solutes appear to fall loosely into three groups. Na, Ca, and Mg follow systematics previously known globally for saline formation waters whereby their concentrations are controlled by fluid-mineral equilibrium. Cl, Br, I, and B are conservatively diluted constituents of some saline endmember that is not solely connate marine. Potassium does not follow any known basinal systematic, and the formation water is supersaturated with respect to SiO2 by an order of magnitude. Meteoric water is not a probable …
Role Of Eintermediaries In The United States Paper Supply Chain, Sanna Maria Kallioranta
Role Of Eintermediaries In The United States Paper Supply Chain, Sanna Maria Kallioranta
LSU Master's Theses
In an attempt to streamline the paper supply chain, paper industry vertical business-to-business eMarketplaces were established to help industry players to decrease inefficiencies in their supply chains, to minimize negative effects of economic cyclicality, and to achieve better visibility. eMarketplaces rode the hype of revolutionizing the way in which industries conduct business, citing the cost savings achieved by expanded market reach, operational efficiencies, aggregated purchasing, and finding the least expensive suppliers. Adoption of eIntermediaries has been lower than expected in the paper industry and many of the paper vertical start-ups failed when the economy softened and the dot.com bubble burst. …
Surface Water Pesticide Contamination In The Upper Terrebonne Basin Of Louisiana, John S. Walther
Surface Water Pesticide Contamination In The Upper Terrebonne Basin Of Louisiana, John S. Walther
LSU Master's Theses
Triazine herbicides are the most heavily used pesticides in the United States. Atrazine and Simazine are the primary triazine herbicides used for broadleaf weed control in the production of corn, sugarcane, and sorghum. Recent monitoring studies of surface waters in the Upper Terrebonne Basin of Louisiana indicate elevated amounts of triazines are running off fields and entering drinking water supplies. Atrazine has been classified as a possible carcinogen by the United States Environmental Protection Agency. Recent epidemiological studies have revealed increases in breast cancer and pre-term births following exposure to triazines at levels detected in drinking water. Non-point source pollution …
Pcr Inhibition And Toxic Effects By Sediment Samples Exposed To Drilling Muds, Neal Gilpin Satterly
Pcr Inhibition And Toxic Effects By Sediment Samples Exposed To Drilling Muds, Neal Gilpin Satterly
LSU Master's Theses
This study evaluated the PCR inhibition and toxic effects by sediment samples exposed to drilling muds. This information was gathered in an attempt to identify what effect, if any, drilling muds had on the microbial community structure in sediments around four specific oil-drilling platforms in the Gulf of Mexico. Sediment samples were taken before and after drilling had taken place around two platforms (GB516 and VK916), and sediment samples were taken after drilling had taken place around two other platforms (MC292 and GB602). After using traditional, non-selective DNA extraction methods, successful amplification took place via PCR with all pre-drilling samples …
An Investigation Of A Salt-Dome Environment At South Timbalier 54, Gulf Of Mexico, Robert E. Little, Jr
An Investigation Of A Salt-Dome Environment At South Timbalier 54, Gulf Of Mexico, Robert E. Little, Jr
LSU Master's Theses
Salt domes have been studied in the Gulf Coast region to look at how, why, and where saline waters are located within these field areas. Fluid flow model and pathway studies can be helpful to the research of saline water migration because it can be correlated to hydrocarbon migration in petroleum exploration. The South Timbalier 54 field occurs over a salt dome that sits at approximately 3,048 meters beneath the seafloor. Two major faults were found originating from the salt dome up into the shallow section of the field. The sands were deposited in fluvial, deltaic, or marine environments. The …
Middle Miocene Grounding Events On The Ross Sea Outer Continental Shelf, Antarctica, Juan Manuel Chow
Middle Miocene Grounding Events On The Ross Sea Outer Continental Shelf, Antarctica, Juan Manuel Chow
LSU Master's Theses
The middle Miocene δ18O enrichments from deep-sea data and eustatic sea level falls are traditionally attributed to expansion of the East Antarctic Ice Sheet. Interpretations of such data have led many to conclude that the West Antarctic Ice Sheet (WAIS) was not well-developed until the late Miocene. In such a scenario, middle Miocene glaciation on the Ross Sea shelf would have had to be minimal, perhaps in the form of ice caps, to be consistent with proxy data. New seismic-stratigraphic analysis of the Ross Sea outer continental shelf suggests that at least five grounding events (ice sheet advances …