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LSU Historical Dissertations and Theses

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Bioanalytical Applications In The Near -Infrared Region Using Fluorescent Covalent And Non-Covalent Probes With Near-Infrared Fluorescence Detection., Clyde Vernon Owens Jr Jan 2000

Bioanalytical Applications In The Near -Infrared Region Using Fluorescent Covalent And Non-Covalent Probes With Near-Infrared Fluorescence Detection., Clyde Vernon Owens Jr

LSU Historical Dissertations and Theses

The research presented in this dissertation entails the preparation, characterization, and analytical application of a series of novel tricarbocyanine, phthalocyanine, and napthalocyanine dyes which can be used as fluorescent probes for bioanalytical assays. The first part of this research focuses on the synthesis of a nuclear staining tricarbocyanine dye used for low-level detection of DNA restriction fragments separated via capillary electrophoresis. The second part focuses on the synthetic, purification, and applications of several tricarbocyanine, phthalocyanine, and naphthalocyanine dyes. The tricarbocyanine dyes were synthesized to contain a heavy atom-modification to enhance k isc through spin-orbit coupling and a reactive functional group …

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Influence Of Weed Control Programs In Glyphosate -Resistant Cotton On Insects And Seedling Disease., Joseph Harry Pankey Jan 2000

Influence Of Weed Control Programs In Glyphosate -Resistant Cotton On Insects And Seedling Disease., Joseph Harry Pankey

LSU Historical Dissertations and Theses

Research conducted from 1997 to 1999 in cotton (Gossypium hirsutum L.) and in non-crop areas evaluated early season insect control and weed control with labeled rates of several insecticides and the herbicide glyphosate applied alone and in combinations. Dicrotophos plus glyphosate improved aphid (Aphis gossypii Glover) control, and thrips (Frankliniella spp.) control was improved with the addition of glyphosate to acephate, dicrotophos, or dimethoate. Redweed (Melochia corchorifolia L.) control was reduced with glyphosate plus endosulfan, and addition of oxamyl, endosulfan, dicrotophos, and imidacloprid reduced prickly sida (Sida spinosa L.) control compared with glyphosate alone. Only the glyphosate plus lambda-cyhalothrin combination …

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Half -Cycle Pulse Ionization Of Diamagnetic Zeeman States In Rydberg Atoms., Chitra Rangan Jan 2000

Half -Cycle Pulse Ionization Of Diamagnetic Zeeman States In Rydberg Atoms., Chitra Rangan

LSU Historical Dissertations and Theses

We study the dynamics of highly excited (Rydberg) atoms in laboratory-scale magnetic fields via their ionization by THz half-cycle pulses (HCPs). A half-cycle pulse is a unipolar electromagnetic pulse that can probe an atomic electron at all points along its orbit around the atomic core. The dynamical evolution of diamagnetic Zeeman states subjected to an ultrashort (picosecond) HCP is calculated for both hydrogen and sodium atoms. Diamagnetic Zeeman states are localized parallel and perpendicular to the magnetic field. We use a grid-based pseudo-potential method to determine these eigenstates of the combined Coulomb-diamagnetic potential. We study states with principal quantum number …

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Amy Beach's Concerto For Piano And Orchestra In C -Sharp Minor, Op. 45: A Historical, Stylistic, And Analytical Study., Katrina Carlson Rushing Jan 2000

Amy Beach's Concerto For Piano And Orchestra In C -Sharp Minor, Op. 45: A Historical, Stylistic, And Analytical Study., Katrina Carlson Rushing

LSU Historical Dissertations and Theses

This study examines Amy Beach's only concerto, the Concerto for Piano and Orchestra in C-sharp Minor, Op. 45. The four-movement, late Romantic work for virtuoso pianist and large orchestra is a significant contribution to the genre, containing well-developed and contrasting themes, interesting and innovative harmonies, and exciting virtuosic display. This monograph explores the concerto from a historical, stylistic, and analytical perspective. The first chapter provides a brief biography of Amy Beach and an overview of her most important compositions. Chapter Two examines the historical significance, the critical reception, and the pianistic style of the concerto. The influences of other late-Romantic …

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I. New Routes To The Synthesis Of Chelating Phosphines For Use In Hydroformylation Catalysis. Ii. Organometallic Complexes Of Convex Hydrocarbons., Barry J. Misquitta Jan 2000

I. New Routes To The Synthesis Of Chelating Phosphines For Use In Hydroformylation Catalysis. Ii. Organometallic Complexes Of Convex Hydrocarbons., Barry J. Misquitta

LSU Historical Dissertations and Theses

The focus of the research done to date has been directed at the modification of the ligand system, et-ph-P4, (Et2P(CH2)2P(Ph)CH 2P(Ph)(CH2)2PEt2) primarily to replace the phenyl groups on the internal phosphorus atoms with various alkyl groups. This would effectively tailor the electron density donated to the rhodium centers and control access to the metal's olefin binding site during hydroformylation catalysis. By changing the organic substituents on the phosphorus atoms, the donor/acceptor properties of the ligand can also be adjusted to optimize binding to the metal. In order to customize our ligand to meet this requirement many routes towards the alkylation …

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Reengineering Of Legacy Systems To Distributed Environments., Miguel Angel Serrano-Vargas Jan 2000

Reengineering Of Legacy Systems To Distributed Environments., Miguel Angel Serrano-Vargas

LSU Historical Dissertations and Theses

The object-oriented paradigm and client/server and distributed technologies have become widely used in the last decade. There is an increasing interest to migrate and reengineer legacy systems to these new hardware technologies and software development paradigms. Software engineers who wish to reengineer such legacy systems face challenges, such as lack of documentation and programs that are difficult to comprehend. Middleware technologies such as CORBA and DCOM make the development of new distributed systems, as well as the migration of legacy systems to distributed platforms, more feasible. Distribution of a system consists of two parts: (1) subsystem decomposition and (2) allocation …

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Magnetic Measurements Of Rare Earth Hexaborides., Alem Abraha Teklu Jan 2000

Magnetic Measurements Of Rare Earth Hexaborides., Alem Abraha Teklu

LSU Historical Dissertations and Theses

The de Haas van Alphen (dHvA) effect is used, using the field modulation method, to study the orientation dependence of the extremal cross-sectional areas of the Fermi surface (FS) and effective masses of CexLa 1--xB6 alloys for x between 0 and 0.05. Previous measurements on these samples, using the pulsed field method, up to x = 1 showed that the FS was spin polarized at very low Ce concentration, at x = 0.05, indicating a spin polarity-dependent scattering mechanism. Moreover, the effective mass was enhanced by the increase of Ce concentration. This was the motivation for the present work which …

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Suspended Sediment And Nutrient Flux Dynamics In Fourleague Bay, Louisiana: The Role Of Winter Cold Fronts And Atchafalaya River Discharge., Brian Christopher Perez Jan 2000

Suspended Sediment And Nutrient Flux Dynamics In Fourleague Bay, Louisiana: The Role Of Winter Cold Fronts And Atchafalaya River Discharge., Brian Christopher Perez

LSU Historical Dissertations and Theses

Material concentrations and fluxes in Oyster Bayou, a tidal channel connecting Fourleague Bay, Louisiana and the northern Gulf of Mexico, were sampled every three hours for 3-months, to examine the importance of atmospheric cold fronts and riverine forcing on the functioning of this estuarine system. The Atchafalaya River was the primary source of nitrate+nitrite (NO2+NO3), total nitrogen (TN), and total phosphorus (TP) to the estuary with greater influence associated with northerly post-frontal winds. Riverine influence coupled with wind-forced resuspension events led to the greatest concentrations of total suspended sediment (TSS) and particulate organic carbon (POC). Ammonium (NH4) concentrations were highly …

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Personal Factors Affecting Sales Performance: Modeling The Effects Of Experience, Competitiveness, Self -Efficacy, Effort, And Creativity., Guangping Wang Jan 2000

Personal Factors Affecting Sales Performance: Modeling The Effects Of Experience, Competitiveness, Self -Efficacy, Effort, And Creativity., Guangping Wang

LSU Historical Dissertations and Theses

Sales performance represents an important ongoing research stream to both academicians and practitioners. It is widely recognized that personal/individual factors affect how salespeople perform. Despite the numerous studies, the search for the most powerful determinants of salesperson performance has largely been unsuccessful (Churchill et al. 1985). This dissertation makes another attempt to understand the effects of select personal factors on salespeople's performance. In particular, a neglected personal factor, salesperson creativity, is introduced as a direct predictor of performance. Based on the social psychological research on creativity and the in-depth personal interviews with sales managers in various industries, the author defines …

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The Effects Of Comparative Advertising Format On Consumer Responses: The Moderating Effects Of Brand Image And Attribute Relevance., Mehmet Ismail Yagci Jan 2000

The Effects Of Comparative Advertising Format On Consumer Responses: The Moderating Effects Of Brand Image And Attribute Relevance., Mehmet Ismail Yagci

LSU Historical Dissertations and Theses

Comparative advertising has become a popular and powerful promotion tactic for companies competing in a highly competitive marketplace. While most research examined comparison advertisements, focusing on one brand being compared to a competitor brand, "within-brand comparison" advertising has been neglected. Within-brand comparison advertising compares the attributes of an extension brand with the attributes of an original or replaced brand. This dissertation examines the relative effectiveness of two forms of comparative advertising tactics, "within-brand comparison" versus "across-brand comparison". The moderating effects of "brand image" and "attribute relevance" and the mediating effect of "ad believability" are also assessed by an experiment. Based …

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Ice -Core Pollen Studies From The Dunde And Guliya Ice Caps, Qinghai -Tibetan Plateau, China., Zuju Yao Jan 2000

Ice -Core Pollen Studies From The Dunde And Guliya Ice Caps, Qinghai -Tibetan Plateau, China., Zuju Yao

LSU Historical Dissertations and Theses

This research provides the first systematic and high-resolution ice-core pollen records from two ice caps in the northern Qinghai-Tibetan Plateau. To facilitate the climatic interpretation of the pollen data from the ice cores, a 30-year pollen record from the Dunde ice core is used to establish the quantitative relationship between pollen and modern climatic parameters. A 2000-year pollen record from the Dunde ice core reveals decadal and century time scale climatic changes. Three dry periods (i.e. A.D. 280--640, 1200--1370, and 1926--1986) and three wet periods are identifiable at Dunde. These results are compatible with other proxy data such as historical …

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Effects Of Dietary L -Carnitine On Female Retired Breeder Rats Fed High Protein And High Fat., Erika Maria Zablah-Bendeck Jan 2000

Effects Of Dietary L -Carnitine On Female Retired Breeder Rats Fed High Protein And High Fat., Erika Maria Zablah-Bendeck

LSU Historical Dissertations and Theses

Carnitine supplementation has been shown to protect animals from ammonia toxicity following an ammonium acetate infusion and to alter body composition (i.e. increase lean mass and decrease body fat) in younger animals. The aims of this study were to address the questions of whether: (1) carnitine lowers blood ammonia levels of rats fed high protein; (2) carnitine decreases the weight gain and body fat of older animals fed high fat; (3) carnitine decreases glucose-induced insulin secretion; and (4) consumption of a high fat diet increases total serum carnitine content. Sprague Dawley retired female breeder rats (n = 64) were stratified …

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Effects Of Dietary Phytase Supplementation On Growth, Nutrient Utilization, And Phytate Degradation In Channel Catfish, Ictalurus Punctatus., Weibing Yan Jan 2000

Effects Of Dietary Phytase Supplementation On Growth, Nutrient Utilization, And Phytate Degradation In Channel Catfish, Ictalurus Punctatus., Weibing Yan

LSU Historical Dissertations and Theses

Phytase supplementation increases the availability of phosphorus in fish diets, and dietary protein utilization might be increased as well by lower phytate concentrations in phytase supplemented diets. Experiments were conducted to determine if weight gain; protein utilization; mineral retention; apparent dry matter, protein and mineral digestibility; and phytate degradation in the stomach of channel catfish fed an all-plant-protein diet could be improved by phytase supplementation. Seven diets were tested: a nutrient complete diet (TC) containing 5% fish meal and six all-plant-protein diets (T1--T6) that contained minimal levels of available phosphorus (0.16%; total P = 0.57%) and zinc (53.37 ppm), but …

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Use Of Pedal In Selected Piano Music Of Alberto Ginastera., Joanna Tuley Burnside Jan 2000

Use Of Pedal In Selected Piano Music Of Alberto Ginastera., Joanna Tuley Burnside

LSU Historical Dissertations and Theses

This monograph examines the piano compositions of Alberto Ginastera and develops possible suggestions for the instruction of pedaling. These suggestions assist teachers in their instruction of piano students, possibly resulting in more authentic, convincing performances. This paper includes suggestions as to why one type of pedaling might be preferable to another. Such suggestions stem not only from a study of harmony, texture, dynamics, notation, and rhythm, but also from comparisons between Ginastera's works that contain pedal markings and those that do not. This monograph draws conclusions about pedaling based upon analysis of selected piano compositions by Ginastera. The repertoire chosen …

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The Impact Of Human Resource Expenditures And The Minimum Foundation Program's Level 3 Subsidy On Academic Productivity In Louisiana., John Paul Beaudoin Jan 2000

The Impact Of Human Resource Expenditures And The Minimum Foundation Program's Level 3 Subsidy On Academic Productivity In Louisiana., John Paul Beaudoin

LSU Historical Dissertations and Theses

This study investigated the impact of instructional salaries with and without a state-sponsored, supply-side subsidy on the academic productivity of schools in Louisiana. The subsidy under investigation was the Level 3 allocation for instructional salaries outlined in Louisiana's Minimum Foundation Program (MFP) that provides fiscal support for educational costs to local school boards. An educational production function model within the general systems framework outlined by Rossmiller and Geske (1977) was used in this study. All selected variables were aggregated to the school-level, which served as the unit of analysis for the study. The study's final sample (n = 296) approximated …

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Essays On The Gain -Loss Pricing Model., Kevin Chun-Hsiung Chiang Jan 2000

Essays On The Gain -Loss Pricing Model., Kevin Chun-Hsiung Chiang

LSU Historical Dissertations and Theses

This dissertation conducts empirical examinations of a new normative (equilibrium) model, the Gain-Loss Pricing Model (GLPM) of Lin (1999a), in which loss aversion is intuitively incorporated into investors' portfolio decisions. In this equilibrium, the risk-return relation is based on the tradeoff between the expected market-related gain of an asset and its expected market-related loss. In addition to its economic intuition, the new model is shown to be more robust than the mean-variance-based Capital Asset Pricing Model (CAPM). This dissertation consists of two essays. The first essay examines the empirical power of the GLPM using NYSE/AMEX/NASDAQ stocks. This testing framework has …

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Evaluation Of Heterologous Promoter Function In The Eastern Oyster (Crassostrea Virginica)., Ta Philip Chih Cheng Jan 2000

Evaluation Of Heterologous Promoter Function In The Eastern Oyster (Crassostrea Virginica)., Ta Philip Chih Cheng

LSU Historical Dissertations and Theses

The goal of this work was to evaluate the feasibility of using antimicrobial peptide gene transfer to enhance oyster immunity. The specific objectives were to: (1) compare the efficiency of collagenase, pronase, and trypsin to dissociate atrium, ventricle and mantle into individual cells for the initiation of primary cell culture; (2) develop cryopreservation conditions to preserve the dissociated cells; (3) establish a serum-free transfection system; (4) evaluate inducible promoter function using the established serum-free transfection system; (5) evaluate the effects of the transfer of antimicrobial peptide genes on oyster immunity. Pronase was found to be the most effective enzyme for …

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Effects Of Cobalt-60 Gamma Irradiation On The Malaysian Prawn Macrobrachium Rosenbergii., Nyanti Lee Jan 2000

Effects Of Cobalt-60 Gamma Irradiation On The Malaysian Prawn Macrobrachium Rosenbergii., Nyanti Lee

LSU Historical Dissertations and Theses

A major obstacle in culture of the Malaysian prawn, Macrobrachium rosenbergii, is the complex social structure whereby a few large males dominate the population and reduce production. The goal of this work was to induce reproductive sterility by use of gamma radiation as a means to increase production. Of the 62 publications related to the use of gamma radiation in aquatic species published between 1938 and 1996, 66% did not indicate performance of dosimetry (dosage verification). Samples were not rotated during irradiation in 98% of these studies, which introduces considerable variation in dose. A dosimetric study in this dissertation found …

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Empirical And Statistical Application Modeling Using On -Chip Performance Monitors., Kirk William Cameron Jan 2000

Empirical And Statistical Application Modeling Using On -Chip Performance Monitors., Kirk William Cameron

LSU Historical Dissertations and Theses

To analyze the performance of applications and architectures, both programmers and architects desire formal methods to explain anomalous behavior. To this end, we present various methods that utilize non-intrusive, performance-monitoring hardware only recently available on microprocessors to provide further explanations of observed behavior. All the methods attempt to characterize and explain the instruction-level parallelism achieved by codes on different architectures. We also present a prototype tool automating the analysis process to exploit the advantages of the empirical and statistical methods proposed. The empirical, statistical and hybrid methods are discussed and explained with case study results provided. The given methods further …

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Ecological Models For Assessing Functions Of Hard Claypan Vernal Pool Wetlands In The Central Valley Of California Using The Hydrogeomorphic (Hgm) Approach For Wetland Assessment., Ellis Joseph Clairain Jr Jan 2000

Ecological Models For Assessing Functions Of Hard Claypan Vernal Pool Wetlands In The Central Valley Of California Using The Hydrogeomorphic (Hgm) Approach For Wetland Assessment., Ellis Joseph Clairain Jr

LSU Historical Dissertations and Theses

Seven vernal pool complexes consisting of numerous shallow wetland depressions were sampled in Sacramento County, California, during the spring and early summer of 1998. Data were obtained to characterize ecological conditions within each complex and to develop models for assessing wetland disturbance and functions. Degree of disturbance, topographic features, soil profiles, and plant species composition and percent cover were examined. Pool area, volume, perimeter, maximum depth, distance from pool to pool, and percent of sample area were computed for 265 vernal pools. Additional detailed topographic and vegetative data were obtained at 68 vernal pools and soil profiles characterized at 64 …

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Synthesis And Characterization Of Novel Rhodium -Tetraphosphine Ligand Complexes., Clinton Hunt Jr Jan 2000

Synthesis And Characterization Of Novel Rhodium -Tetraphosphine Ligand Complexes., Clinton Hunt Jr

LSU Historical Dissertations and Theses

The synthesis and characterization of novel rhodium-tetraphosphine ligand complexes have been completed. The purpose of this dissertation research was to better characterize our novel binuclear hydroformylation catalyst by synthesizing and characterizing compounds with various combinations of rhodium centers and a binucleating tetratertiary phosphine ligand, et,ph-P4 [et,ph-P4 = (Et 2PCH2CH2)(Ph)PCH2P(Ph)(CH2CH 2PEt2)]. Eight new complexes, [Rh3(rac -et,ph-P4)2](BF4)3, 17, [Rh2(meso-et,ph-P4)2](PF6)2, 26, [Rh2(rac,meso-et,ph-P4)2](Cl) 2, 26a, [Rh2(rac-et,ph-P4) 2](BF4)2, 28, [RhCl2( rac-et,ph-P4)]BF4·toluene, 32a, [RhCl 2(rac-et,ph-P4)]BF4·MeOH, 32b, [RhCl2(rac-et,ph-P4)]BF4·2DCM, 32c, and [RhCl2(rac-et,ph-P4)]BF4 ·acetone, 32d, have resulted from these research efforts and are discussed in Chapters 2--4. 31P NMR analyses of these complexes show that none of these are …

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A Cross-Sectional Study Of Prevalence And Risk Factors For Major Goat Diseases In Eastern And Western Uganda: Results And Exploration Of Biases., Edmond Kato Kabagambe Jan 2000

A Cross-Sectional Study Of Prevalence And Risk Factors For Major Goat Diseases In Eastern And Western Uganda: Results And Exploration Of Biases., Edmond Kato Kabagambe

LSU Historical Dissertations and Theses

In 1998 a cross-sectional study on goat health and management was conducted in eastern and western Uganda. This study involved 1518 goats which were distributed in 145 herds in 5 districts, namely Kumi, Masaka, Mbarara, Soroti and Ssembabule. Cluster sampling was used to select farms across the two regions. A questionnaire on goat health, management and constraints to production was administered to 145 goat owners. Blood and nasal swabs were collected from a random sample of goats. For each goat a physical examination was performed to detect presence of clinical conditions. Serological assays for contagious caprine pleuropneumonia (CCPP), peste des …

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Habitat And Demography Of Understory Trees In Mixed Species Hardwood Forests In Northern Florida, United States Of America., Charles Kwit Jan 2000

Habitat And Demography Of Understory Trees In Mixed Species Hardwood Forests In Northern Florida, United States Of America., Charles Kwit

LSU Historical Dissertations and Theses

Temperate mixed-species hardwood forests of northern Florida, USA, contain a high diversity of understory tree species, some of which have been hypothesized to require disturbance (e.g., hurricanes and/or treefall gaps). Taxus floridana is a rare understory conifer endemic to midslopes of ravines of the Apalachicola River Bluffs, and is found primarily on north-facing slopes. Vegetation sampling in the southern portion of T. floridana's range revealed the presence of an upslope oak-hickory community of suggested recent origin, and higher densities of American beech (Fagus grandifolia ), southern magnolia (Magnolia grandiflora), and evergreen understory trees on north-facing midslopes with T. floridana than …

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Reformers In The Marketplace Of Ideas: Student Activism And American Democracy In Cold War Los Angeles., Kurt Edward Kemper Jan 2000

Reformers In The Marketplace Of Ideas: Student Activism And American Democracy In Cold War Los Angeles., Kurt Edward Kemper

LSU Historical Dissertations and Theses

Contemporary opinion and much scholarship frequently interprets student activists from the 1960s and 1970s as radical critics of both American society and foreign policy, seeking revolutionary changes in both and caring little of the consequences to the existing order. In fact, conservative forces and values based on democratic capitalism drove student activism of the period. Students' core values of equality of opportunity, equality of and before the law, and faith in the democratic process motivated their activism not just towards civil rights and the war in Vietnam, but also towards issues of student funding and institutions, indicating that self-interest served …

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Three Essays On Political Economy And International Trade., Far-Tsair Lai Jan 2000

Three Essays On Political Economy And International Trade., Far-Tsair Lai

LSU Historical Dissertations and Theses

In the standard common agency model of politics, the interest groups always lobby a single policy-making entity for policy favor. To deal with this unreality, I step in some issues about the trade policy making that is entangled with the multiplicity of public decision-makers. My study cooperates multi-agent and the common agency model to analyze the trade policy making under the political system that is controlled by a number of lawmakers. The analysis points out that the committee of symmetric lawmakers behaves like a single government but the equilibrium policy is not efficient. Because the presence of multiple players on …

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"Shadow Of The Blues" And "Dove Sta Amore": Selected Songs Of John Musto., Jessica Molin Jan 2000

"Shadow Of The Blues" And "Dove Sta Amore": Selected Songs Of John Musto., Jessica Molin

LSU Historical Dissertations and Theses

This paper reflects my research and synthesis of the songs of Shadow of the Blues and Dove Sta Amore, and my direct work with the composer, John Musto. I find his music to be intriguing, and feel this guide to his music will be of value to singers and educators. My preliminary research revealed that little had been written about Musto. I contacted the composer, interviewed and studied the repertoire with him in New York City, prepared this guide and performed the songs in recital. The quality of John Musto's songs secures for him a place in the top rank …

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Modeling Escherichia Coli Concentration In Surface Runoff: The Ecoli Model., Teck Yee Ling Jan 2000

Modeling Escherichia Coli Concentration In Surface Runoff: The Ecoli Model., Teck Yee Ling

LSU Historical Dissertations and Theses

A biological model, ECOLI, is developed that is capable of continuously simulating E. coli concentration in surface runoff from agricultural land applied with manure. The model was calibrated and validated by using data from field-scale studies at Franklinton, Louisiana. During validation the model was interfaced with GLEAMS-SWT model to obtain the necessary hydrologic and erosion variables as input to the ECOLI model. The ECOLI model was found to perform best when simulating runoff concentration following the first application of waste. For reapplication of waste within 50 days, the trend of decrease over time was well-simulated but simulated E. coli concentrations …

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State-Resolved Molecular Photoionization Dynamics Of Polyatomic Systems: Effects Of Non-Linear Changes In Molecular Geometry., James Scott Miller Jan 2000

State-Resolved Molecular Photoionization Dynamics Of Polyatomic Systems: Effects Of Non-Linear Changes In Molecular Geometry., James Scott Miller

LSU Historical Dissertations and Theses

An important topic in the absorption of vacuum ultraviolet photons by molecules is the correlation between electronic and nuclear degrees of freedom during photoionization. However, no previous investigations have probed the correlation between bending excitation and photoejection dynamics over a wide spectral range. We present the first such studies by reporting the influence of bending excitation following CO2 3sigmau --1 and N2O 7sigma--1 photoionization over the photon energy range (15 eV < hvexc < 200 eV). Using dispersed fluorescence spectroscopy in conjunction with synchrotron radiation, we determine the vibrational branching ratio v+ = 0,1,0 0,0,0 for the CO2+ (B 2Sigmau+) and N2O+ (A 2Sigma+) electronic states. The relative rate of production of the upsilon2 = 1 upper vibrational state varies over a broad ionization energy range, and in ways that are largely unanticipated. These branching ratios exhibit a strong thermal dependence, and we are able to separate out effects due to hot-band excitation from those that are due to vibronic coupling. The data indicate that the continuum electron is responsible for the observed energy dependence in CO2 3sigma u--1 photoionization. This is a previously unobserved result. Additional studies examine the influence of simultaneous excitation in the bending and symmetric stretching modes in N2O+ [A 2Sigma+, v + = (1,1,0)] to determine the effect of changing the energy separation of vibronically coupled potential surfaces. Finally, the CF4 + [D 2A1, v+ = (1,0,0,0)/(0,0,0,0)] branching ratio is studied, which provides the first experimental observation of a predicted low-energy shape resonance in this photoionization pathway.

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Atomic And Electronic Properties Of Neutral And Cationic Metallic Clusters., Andrew Marc Kolchin Jan 2000

Atomic And Electronic Properties Of Neutral And Cationic Metallic Clusters., Andrew Marc Kolchin

LSU Historical Dissertations and Theses

We find optimal atomic and electronic structures for neutral and singly, positively charged clusters of beryllium and beryllium-lithium (of the form BeLik) using density functional theory in the local spin density approximation. Ions are moved with a steepest descent method, and the electronic wave functions optimized using a fictitious dynamics with simulated annealing, as conceived by Car and Parrinello. Shell-like orbitals, filling angular momentum states in the order: 1s 2p 2s 1d, are obtained for the beryllium clusters. The same ordering is found for the BeLik clusters which indicates a departure from the ordering found in pure alkali clusters by …

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Visual And Semiochemical Disruption Of Host Finding In Pine Bark Beetles., Brian Lee Strom Jan 2000

Visual And Semiochemical Disruption Of Host Finding In Pine Bark Beetles., Brian Lee Strom

LSU Historical Dissertations and Theses

Pine bark beetles (Coleoptera: Scolytidae) affect ecological and anthropocentric processes in coniferous forests. Certain aggressive species, particularly among the Dendroctonus, cause widespread damage. As forests become increasingly valued for diverse commodities, protection strategies must be developed to meet a wide variety of landowner values. Disruption of the host selection process is one important strategy for managing pine bark beetles. The objectives of this work were: to describe the oleoresin flow and constituency of loblolly pines (Pinus taeda) whose parents escaped mass attack by the southern pine beetle, Dendroctonus frontalis (SPB); to ascertain the utility of altering visual silhouettes to disrupt …

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