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Nonlinear Equations And Wavelets, A. Ludu, R. F. O'Connell, J. P. Draayer Feb 2003

Nonlinear Equations And Wavelets, A. Ludu, R. F. O'Connell, J. P. Draayer

Faculty Publications

Wavelet-inspired approaches for localized solutions of nonlinear partial differential equations (NDPE) were presented. A multi-scale similarity analysis was used which gives specific relations between the velocity, amplitude and width of localized solutions of nonlinear differential equations. This approach does not need the explicit form of the exact solutions.

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Climatic Influences On Riverine Nitrate Flux: Implications For Coastal Marine Eutrophication And Hypoxia, Dubravko Justic, R. Eugene Turner, Nancy N. Rabalais Feb 2003

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 …

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Matrix Composition Affects The Spatial Ecology Of A Prairie Planthopper, Kyle J. Haynes, James T. Cronin Jan 2003

Matrix Composition Affects The Spatial Ecology Of A Prairie Planthopper, Kyle J. Haynes, James T. Cronin

Faculty Publications

To date, there is a lack of well-controlled field experiments that disentangle the effects of the intervening matrix from other landscape variables (e.g., patch geography or quality) that might influence animal dispersal among patches. We performed a field experiment to investigate how the movement of a delphacid planthopper (Prokelisia crocea) among discrete patches of prairie cordgrass (Spartina pectinata) is affected by the composition of the matrix (mudflat, native nonhost grasses, and the introduced grass smooth brome [Bromus inermis]). Within each matrix type, marked planthoppers were released onto experimental cordgrass patches that were made identical in size, isolation, and host plant …

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Coloring Graphs With Crossings, Wei Zhao Jan 2003

Coloring Graphs With Crossings, Wei Zhao

Honors Capstones

No abstract provided.

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Movement And Spatial Population Structure Of A Prairie Planthopper, James T. Cronin Jan 2003

Movement And Spatial Population Structure Of A Prairie Planthopper, James T. Cronin

Faculty Publications

The transfer of organisms among patches is a key process influencing the spatial structure and regional dynamics of a population; yet, detailed experimental studies of animal movement among patches are uncommon. I performed a series of mark-recapture studies to quantify the movement of a planthopper, Prokelisia crocea (Hemiptera: Delphacidae), among discrete patches of its host plant, prairie cordgrass (Spartina pectinata). Results from these dispersal studies were used to predict the natural distributions and to characterize the spatial population structure of P. crocea. Planthopper emigration loss per patch increased linearly with the density of female conspecifics and was nonlinearly related to …

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A Representation Theorem For Recovering Contraction Relations Satisfying Wci, Zhaohui Zhu, Bin Li, Xi'an Xiao, Shifu Chen, Wujia Zhu Jan 2003

A Representation Theorem For Recovering Contraction Relations Satisfying Wci, Zhaohui Zhu, Bin Li, Xi'an Xiao, Shifu Chen, Wujia Zhu

Faculty Publications

A notion of an image structure associated with the canonical epistemic state is introduced. Based on it, we get a representation result for recovering contraction inference relations satisfying the condition weak conjunctive inclusion (wci) in terms of F-standard epistemic AGM states. In effect, this result establishes a representation theorem for belief contraction functions satisfying AGM postulates (k-1) - (k-7), and Rott's (wci) and (k-8c), and hence generalizes Rott's corresponding result in the finite framework. © 2002 Elsevier Science B.V. All rights reserved.

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Packing Cycles In Graphs, Ii, Guoli Ding, Zhenzhen Xu, Wenan Zang Jan 2003

Packing Cycles In Graphs, Ii, Guoli Ding, Zhenzhen Xu, Wenan Zang

Faculty Publications

A graph G packs if for every induced subgraph H of G, the maximum number of vertex-disjoint cycles in H is equal to the minimum number of vertices whose deletion from H results in a forest. The purpose of this paper is to characterize all graphs that pack. © 2002 Elsevier Science (USA). All rights reserved.

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Multiplicative Renormalization And Generating Functions I, Nobuhiro Asai, Izumi Kubo, Hui Hsiung Kuo Jan 2003

Multiplicative Renormalization And Generating Functions I, Nobuhiro Asai, Izumi Kubo, Hui Hsiung Kuo

Faculty Publications

Let μ be a probability measure on the real line with finite moments of all orders. Apply the Gram-Schmidt orthogonalization process to the system {1, x, x2, . . ., xn, . . .} to get orthogonal polynomials Pn(x), n ≥ 0, which have leading coefficient 1 and satisfy (x-αn)Pn(x) = Pn+1(x) +ωnPn-1(x). In general it is almost impossible to use this process to compute the explicit form of these polynomials. In this paper we use the multiplicative renormalization to develop a new method for deriving generating functions for a large class of probability measures. From a generating function for …

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Optimization Of Resonances In Photonic Crystal Slabs, Robert P. Lipton, Stephen P. Shipman, Stephanos Venakides Jan 2003

Optimization Of Resonances In Photonic Crystal Slabs, Robert P. Lipton, Stephen P. Shipman, Stephanos Venakides

Faculty Publications

Variational methods are applied to the design of a two-dimensional lossless photonic crystal slab to optimize resonant scattering phenomena. The method is based on varying properties of the transmission coefficient that are connected to resonant behavior. Numerical studies are based on boundary-integral methods for crystals consisting of multiple scatterers. We present an example in which we modify a photonic crystal consisting of an array of dielectric rods in air so that a weak transmission anomaly is transformed into a sharp resonance.

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Design-Dependent Loads In Topology Optimization, Blaise Bourdin, Antonin Chambolle Jan 2003

Design-Dependent Loads In Topology Optimization, Blaise Bourdin, Antonin Chambolle

Faculty Publications

We present, analyze, and implement a new method for the design of the stiffest structure subject to a pressure load or a given field of internal forces. Our structure is represented as a subset S of a reference domain, and the complement of S is made of two other “phases”, the “void” and a fictitious “liquid” that exerts a pressure force on its interface with the solid structure. The problem we consider is to minimize the compliance of the structure S, which is the total work of the pressure and internal forces at the equilibrium displacement. In order to prevent …

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Book Reviews Jan 2003

Book Reviews

1650-1850: Ideas, Aesthetics, and Inquiries in the Early Modern Era

No abstract provided.

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Ebenezer Sibley And The Royal Ark Masons, Susan M. Sommers Jan 2003

Ebenezer Sibley And The Royal Ark Masons, Susan M. Sommers

1650-1850: Ideas, Aesthetics, and Inquiries in the Early Modern Era

No abstract provided.

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Aesthetics Of Coldness The Romantic Scene And A Glimpse At Baudelaire, Jurgen Klein Jan 2003

Aesthetics Of Coldness The Romantic Scene And A Glimpse At Baudelaire, Jurgen Klein

1650-1850: Ideas, Aesthetics, and Inquiries in the Early Modern Era

No abstract provided.

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Decoherence In A Driven Three-Level System, A. R.P. Rau, Weichang Zhao Jan 2003

Decoherence In A Driven Three-Level System, A. R.P. Rau, Weichang Zhao

Faculty Publications

Dissipation and decoherence, and the evolution from pure to mixed states in quantum physics, are handled through master equations for the density matrix. Master equations such as the Lindblad equation preserve the trace of this matrix. Viewing them as first-order time-dependent operator equations for the elements of the density matrix, a unitary integration procedure can be adapted to solve for these elements. A simple model for decoherence preserves the Hermiticity of the density matrix. A single, classical Riccati equation is the only one requiring numerical handling to obtain a full solution of the quantum evolution. The procedure is general, valid …

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Detectability Of Gravitational Waves From Sn 1987a, Giovanni Santostasi, Warren Johnson, Juhan Frank Jan 2003

Detectability Of Gravitational Waves From Sn 1987a, Giovanni Santostasi, Warren Johnson, Juhan Frank

Faculty Publications

We discuss the potential for the detection of gravitational waves from a rapidly spinning neutron star produced by supernova (SN) 1987A, taking the parameters claimed by Middleditch et al. at face value. Assuming that the dominant mechanism for spin-down is gravitational waves emitted by a freely precessing neutron star, it is possible to constrain the wobble angle, the effective moment of inertia of the precessing crust, and the crust cracking stress limit. Our analysis suggests that if the interpretation of the Middleditch data is correct, the compact remnant of SN 1987A may well provide a predictable source of gravitational waves …

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Developing A User-Process Model For Designing Menu-Based Interfaces: An Exploratory Study, Boryung Ju, Myke Gluck Jan 2003

Developing A User-Process Model For Designing Menu-Based Interfaces: An Exploratory Study, Boryung Ju, Myke Gluck

Faculty Publications

The purpose of this study was to organize menu items based on a user-process model and implement a new version of current software for enhancing usability of interfaces. Dervin & Nilan's time-line method is used to develop a user-process model for user interface design. We developed a user process model drawn from actual users' understanding of their goals and strategies to solve their information needs by using Dervin's Sense-Making Theory with sense-making interviews. Six experienced subjects were recruited for the sense-making interviews. Each subject went through a learning/exploration session, and was asked to recall and describe specific information needs throughout …

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Downstream Hydraulic Geometry Relations: 2. Calibration And Testing, Vijay P. Singh, Chih Ted Yang, Zhi Qiang Deng Jan 2003

Downstream Hydraulic Geometry Relations: 2. Calibration And Testing, Vijay P. Singh, Chih Ted Yang, Zhi Qiang Deng

Faculty Publications

Using 456 data sets under bank-full conditions obtained from various sources, the geometric relations, derived in part 1 [Singh et al., 2003], are calibrated and verified using the split sampling approach. The calibration of parameters shows that the change in stream power is not shared equally among hydraulic variables and that the unevenness depends on the boundary conditions to be satisfied by the channel under consideration. The agreement between the observed values of the hydraulic variables and those predicted by the derived relations is close for the verification data set and lends credence to the hypotheses employed in this study.

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Nonresonance Conditions For Arrangements, D. C. Cohen, A. Dimca, P. Orlik Jan 2003

Nonresonance Conditions For Arrangements, D. C. Cohen, A. Dimca, P. Orlik

Faculty Publications

We prove a vanishing theorem for the cohomology of the complement of a complex hyperplane arrangement with coefficients in a complex local system. This result is compared with other vanishing theorems, and used to study Milnor fibers of line arrangements, and hypersurface arrangements.

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Removal Of Sustained Casing Pressure Utilizing A Workover Rig, Kevin Soter Jan 2003

Removal Of Sustained Casing Pressure Utilizing A Workover Rig, Kevin Soter

LSU Master's Theses

This thesis will analyze the techniques used during the 1989 and 1990 workover programs as well as subsequent operations in 1991/1992. It will also present the techniques and results of the most recent 1999 workover program undertaken to alleviate the most persistent sustained casing pressure (SCP) in a mature Gulf of Mexico field. An extensive literature review is included to better illustrate the complexity of the issues involved and possible SCP mechanisms. The field was drilled during the 1980’s and SCP has been prevalent in some cases previous to initial completion operations. Previous remedial programs resulted in limited success in …

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Pulsed River Flooding Effects On Sediment Deposition In Breton Sound Estuary, Louisiana, Katherine Wheelock Jan 2003

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 …

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Address Register Assignment For Reducing Code Size, M. Kandemir, M. J. Irwin, G. Chen, J. Ramanujam Jan 2003

Address Register Assignment For Reducing Code Size, M. Kandemir, M. J. Irwin, G. Chen, J. Ramanujam

Faculty Publications

In DSP processors, minimizing the amount of address calculations is critical for reducing code size and improving performance since studies of programs have shown that instructions that manipulate address registers constitute a significant portion of the overall instruction count (up to 55%). This work presents a compiler-based optimization strategy to reduce the code size in embedded systems. Our strategy maximizes the use of indirect addressing modes with post-increment and post-decrement capabilities available in DSP processors. These modes can be exploited by ensuring that successive references to variables access consecutive memory locations. To achieve this spatial locality, our approach uses both …

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Stock Price Modeling And Insider Trading Theory, Jessica J. Guillory Jan 2003

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 …

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Heat Transfer In Outdoor Aquaculture Ponds, Jonathan Lamoureux Jan 2003

Heat Transfer In Outdoor Aquaculture Ponds, Jonathan Lamoureux

LSU Master's Theses

An energy balance was developed for heated and unheated earthen aquaculture ponds to 1) determine the relative importance of energy transfer mechanism affecting pond temperature; 2) predict pond temperatures; 3) estimate the energy required to control pond temperatures, and 4) recommend efficient heating and cooling methods. PHATR (Pond Heating and Temperature Regulation), a computer program using 4th order Runge-Kutta numerical method was developed to solve the energy balance using weather, flow rate and pond temperature data. By comparing measured and modeled pond temperatures, the average difference (the average bias) was 0.5°C for unheated ponds and 2.4°C for heated ponds. The …

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Compositional Systematics Of Deep, Low Salinity Formation Waters In The Upper Wilcox Of Southeastern Texas, Kathleen (Kt) Moran Jan 2003

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 …

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Freeway Accident Analysis Using Second Order Statistics, Khasim Khasimul Shaik Jan 2003

Freeway Accident Analysis Using Second Order Statistics, Khasim Khasimul Shaik

LSU Master's Theses

This research focuses on the use of historical freeway traffic data for comparison of the precursory traffic conditions to that accident occurrence by using 15-minute traffic speed contour maps. The second order statistics measures, namely angular second moment (ASM), contrast and entropy were used as the traffic performance measures in order to compare the two situations. The data used is from I-4 freeway traffic condition database, stored in a SQL server and 1999 year accident database for the same I-4 freeway. The study section is located in Orlando, Florida. The approach shows an approach to understand the performance of the …

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The Effects Of Sediment Grain Size And Oil Exploration On Microbial Atp Biomass, Eric Tyson Guilbeau Jan 2003

The Effects Of Sediment Grain Size And Oil Exploration On Microbial Atp Biomass, Eric Tyson Guilbeau

LSU Master's Theses

Adenosine triphosphate (ATP) is a unique biochemical indicator of active microbial biomass and its relationship to environmental conditions. Its assay in sediments is complicated, however, by adsorptive loss to the sediment matrix and subsequent interferences in the luciferin-luciferase assay by compounds released during the extraction process. Corrections must be applied to correct for these losses and we describe a novel approach using radioactive ATP to correct for ATP adsorption. The sediment matrix also plays a significant role in determining both the magnitude of the ATP pool and the extent of the ATP adsorptive loss. Coarser sediments were found to have …

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Comparative Analysis Of State Environmental Enforcement In Region Six Of The United States, Rebecca Marcus Jan 2003

Comparative Analysis Of State Environmental Enforcement In Region Six Of The United States, Rebecca Marcus

LSU Master's Theses

Through intense studies of agency audits, EPA policies and documents, state environmental compliance data and state agency issued documents, I have evaluated the enforcement programs of Region Six state environmental agencies. The four elements utilized to perform this evaluation were listed in EPA compliance assurance program documents. The analysis was conducted by comparing state program performance in each element. Element 1 is the “appropriate identification of violations.” Element 2 is the “timely issuance of enforcement actions.” Element 3 is the “escalation of enforcement actions when violations continue.” Element 4 is the “ability to assess and collect penalties.” These elements are …

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Sugarcane Seed Response To 2,4-D And Alternative Herbicides For Red Morningglory (Ipomoea Coccinea L.) Control, Jonathan Daniel Siebert Jan 2003

Sugarcane Seed Response To 2,4-D And Alternative Herbicides For Red Morningglory (Ipomoea Coccinea L.) Control, Jonathan Daniel Siebert

LSU Master's Theses

Field studies conducted over two growing seasons evaluated the effect of 2,4-D applied at 1.6 kg ai/ha to LCP 85-384 sugarcane (Saccharum interspecific hybrid) 7, 5, 3, and 1 wk before planting (WBP). Sugarcane was planted in mid-September using both whole stalk and billet (45 cm) seed pieces. When 2,4-D was applied 5 wk or closer to planting, sugarcane shoot emergence and population averaged across planting methods was reduced 5, 7, and 28 wk after planting (WAP) when compared to the nontreated control. Sugarcane height in one of two years was reduced when 2,4-D was applied 5 wk or closer …

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Diet Similarity Of Pen-Raised Versus Native, Louisiana White-Tailed Deer In Southeastern Louisiana, Kristopher Scott Davis Jan 2003

Diet Similarity Of Pen-Raised Versus Native, Louisiana White-Tailed Deer In Southeastern Louisiana, Kristopher Scott Davis

LSU Master's Theses

Previous studies have shown that pen-raised deer may be already predisposed to malnutrition at a higher rate then their native counterparts because they are normally raised on a pelleted ration and may not forage efficiently once released into wild habitats. Therefore, twenty pen-raised white-tailed deer that were offspring of deer obtained from Missouri (Odocoileus virginianus) were released onto a marsh pump-off habitat in southeast Louisiana (Da Bunch) to compare their diets to the diets of the native, wild, white-tail deer population already established in the area over four consecutive seasons to test this hypothesis. The microhistological analysis technique was used …

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Detrital Tourmaline As An Indicator Of Provenance: A Chemical And Sedimentological Study Of Modern Sands From The Black Hills, South Dakota, David Brent Viator Jan 2003

Detrital Tourmaline As An Indicator Of Provenance: A Chemical And Sedimentological Study Of Modern Sands From The Black Hills, South Dakota, David Brent Viator

LSU Master's Theses

Detrital tourmaline has proven useful as a provenance indicator mineral of ancient sedimentary/metasedimentary units due to its presence in many rock types, chemical responsiveness to environments of formation, complex and variable chemical compositions, high resistance to chemical and mechanical weathering, and stability through diagenesis and metamorphism. This study further establishes detrital tourmaline as a provenance indicator mineral by examining the chemical and sedimentological relationships between modern detrital tourmalines in the sediments of the Black Hills, South Dakota, USA, and in situ tourmalines from southern Black Hills’ tourmaline-bearing metasedimentary rocks, granites, and rare-element enriched pegmatites. Results show that detrital tourmaline is …

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