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1997

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The Synthesis Of Novel Phosphine-Modified Ligands For Use In Bimetallic Hydroformylation., Howard Frederick Koch Iii Jan 1997

The Synthesis Of Novel Phosphine-Modified Ligands For Use In Bimetallic Hydroformylation., Howard Frederick Koch Iii

LSU Historical Dissertations and Theses

The tetraphosphine ligand, Et$\sb2$P(CH$\sb2)\sb2$P(Ph)CH$\sb2$P(Ph)(CH$\sb2)\sb2$PEt$\sb2 ,$ et,ph-P4, was designed to be a binucleating ligand for use in bimetallic hydroformylation catalysis. This ligand can be tailored for both electronic and steric factors at the internal and external phosphorus atoms. It is hoped that through careful tuning of this ligand, the rate and selectivity of our bimetallic catalyst can be optimized for various substrates. Modification of the original ligand may also lead us to a better understanding of the mechanism involved in the catalytic cycle. My goal has been to replace the phenyl substituents on the internal phosphorus atoms with various alkyl groups. …

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Peroxynitrite Mediated Oxidations: Spin Trap Studies; Nitration And Hydroxylation Of Phenol Result From Different Intermediates; Co(2) Catalyzes The Decomposition Of Peroxynitrite., Jean-Noel Lemercier Jan 1997

Peroxynitrite Mediated Oxidations: Spin Trap Studies; Nitration And Hydroxylation Of Phenol Result From Different Intermediates; Co(2) Catalyzes The Decomposition Of Peroxynitrite., Jean-Noel Lemercier

LSU Historical Dissertations and Theses

In the first project the spin trap DMPO was used to probe for the production of hydroxyl radicals from peroxynitrite. Peroxynitrite reacts with DMPO to give $\sp\cdot$DMPO-OH, suggesting that $\sp\cdot$DMPO-OH results from a reaction between DMPO and HOONO or between DMPO and an activated intermediate of HOONO. Thiols produce a large increase in the $\sp\cdot$DMPO-OH signal intensity. Experiments employing SOD suggest that this increase results from the decomposition of $\sp\cdot$DMPO-OOH. These results are incompatible with the decomposition of peroxynitrite to form $\sp\cdot$OH but suggest that an intermediate of HOONO is produced that is less reactive and more selective than the …

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Integrated Pest Management Tactics For Control Of Cabbage Looper And Diamondback Moth In Cabbage., Paul Wesley Ivey Jan 1997

Integrated Pest Management Tactics For Control Of Cabbage Looper And Diamondback Moth In Cabbage., Paul Wesley Ivey

LSU Historical Dissertations and Theses

Population density estimates, yield data, damage rating, and marketability of cabbage were used to assess the effectiveness of integrating several control tactics--an action threshold, host plant resistance, intercropping (companion planting), microbial control, and pesticide use reduction--for managing the diamondback moth (DBM), Plutella xylostella (L.), and the cabbage looper (CL), Trichoplusia ni (Hubner), in cabbage and in protecting beneficial arthropods. An action threshold of six DBM larvae per plant was inadequate for making insecticide application decisions because cabbage plots treated based on this action threshold had significantly higher densities of CL and DBM larvae, higher damage rating and yield loss, and …

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The Evolution Of Landscapes And Lineages In Pitcher Plants And Their Moths., Margaret Ellen Oard Jan 1997

The Evolution Of Landscapes And Lineages In Pitcher Plants And Their Moths., Margaret Ellen Oard

LSU Historical Dissertations and Theses

Pitcher plants and pitcher plant moths exhibit two prominent themes in the long evolutionary history between plants and insects. These themes are carnivory and herbivory. In pitcher plants, the leaf has been modified into an elegant pitfall trap enabling these plants to subsist at both the producer and consumer trophic levels. Of the numerous insect species intimately associated with pitcher plants, pitcher plant moths are the only inquilines which have evolved the capacity to disrupt both the carnivore and photosynthetic functions of the host plant. The carnivorous habit, considered an adaptation for nutrient deficient environments, has contributed to species radiations …

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Stochastic Techniques For The Solution Of Electrostatic Problems With Applications To Electron Optics., Elias Kougianos Jan 1997

Stochastic Techniques For The Solution Of Electrostatic Problems With Applications To Electron Optics., Elias Kougianos

LSU Historical Dissertations and Theses

We apply stochastic techniques towards the solution of the two-dimensional Laplace's equation in boundary value problems encountered in the calculation of electrostatic potentials in electron lenses and deflectors. The justification of these techniques arises from an astonishingly simple but far-reaching principle, which has been known for a long time but has been rarely used: the potential at any point in the interior of a charge-free region can be calculated by performing random walks starting at this point and terminating at the boundary of the region--the potential is then the average of the potential boundary values (assumed known) over the random …

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A Double-Hurdle Expenditure Analysis Of Nonconsumptive Wildlife-Related Recreation., Yeong-Nain Chi Jan 1997

A Double-Hurdle Expenditure Analysis Of Nonconsumptive Wildlife-Related Recreation., Yeong-Nain Chi

LSU Historical Dissertations and Theses

This study utilized cross-sectional data obtained from the 1991 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation to analyze the expenditures and consumption of nonconsumptive wildlife related recreation in the Lower Mississippi Valley Ecosystem area. In the process of selecting an appropriate model most consistent with individuals' consumption behavior associated with nonconsumptive wildlife related recreation, the tobit model and the double-hurdle model for both the primary nonresidential and residential expenditure models were evaluated. Based on the Lagrange multiplier test and the likelihood ratio test results, the double-hurdle model fit the data much better than the tobit model. The hypothesis that …

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Characterization Of The Cytochromes P450-Dependent Hepatic Microsomal Monooxygenase System Of The American Alligator, Alligator Mississippiensis: Influence Of Xenobiotic Chemicals., Robin Parsons Ertl Jan 1997

Characterization Of The Cytochromes P450-Dependent Hepatic Microsomal Monooxygenase System Of The American Alligator, Alligator Mississippiensis: Influence Of Xenobiotic Chemicals., Robin Parsons Ertl

LSU Historical Dissertations and Theses

Alligator mississippiensis contains all of the components of the hepatic microsomal mixed function oxidase system. In general, basal and induced levels of P450 specific content, immunochemically detected abundance and examined activities are less than in mammals. In alligator at least two classes of P450s are inducible by xenobiotics: those induced by 3-methylcholanthrene (3MC) and those induced by phenobarbital (PB). PB and 3MC induce multiple P450 isoforms as detected by western blot and enzymatic analyses. The induced level of alkoxyphenoxazone O-dealkylation (AROD) was 10- to 100-fold lower in alligator than in rat, with the exception of phenylbenzyloxyphenoxazone O-dealkylation. In contrast to …

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Synthesis And Photophysical Characterization Of Near-Ir Probes For Bioanalytical Applications., James Henry Flanagan Jr Jan 1997

Synthesis And Photophysical Characterization Of Near-Ir Probes For Bioanalytical Applications., James Henry Flanagan Jr

LSU Historical Dissertations and Theses

The research presented in this dissertation involves the synthesis and photophysical characterization of a series of tricarbocyanine dyes which can be used as fluorescent labels for bioanalytical applications. All of these dyes were synthesized to contain a heavy-atom modification to enhance k$\sb{\rm isc}$ through spin-orbit coupling and a functional group (isothiocyanate or succinimidyl ester) which is reactive towards primary amines. The spectroscopic characterization of the various chromophores was examined using absorbance and fluorescence measurements, time-correlated fluorescence, and flash photolysis. The dyes exhibit absorbance and fluorescence maxima in the near-IR (750-810 nm) with large $\varepsilon$ ($\sim$200,000 M$\sp{-1}$cm$\sp{-1})$ and $\Phi\sb{\rm f}\sim0.05$-0.15. Dyes …

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Dna Wrapping And The Nature Of Interaction Between E. Coli Rna Polymerase And Promoter Dna., Parisa Jazbi Jan 1997

Dna Wrapping And The Nature Of Interaction Between E. Coli Rna Polymerase And Promoter Dna., Parisa Jazbi

LSU Historical Dissertations and Theses

Regulation of transcription most often occurs at the stage of initiation. RNA polymerase binding to the transcription start site, the promoter, is influenced by many nucleotide sequence elements. The predominant recognition sequences are those bound by the $\sigma$ subunit of RNA polymerase located at $-$10 and $-$35 relative to initiation site of most promoters. Another element involved in this regulation is intrinsic DNA curvature. In this study, the contribution of intrinsically curved DNA immediately upstream of the promoter to the interaction between Escherichia coli RNA polymerase and this DNA was examined. DNase I footprinting analysis confirmed that RNA polymerase wraps …

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Identification And Quantification Of S-(2-(N(7)-Guanyl)Ethyl)Glutathione Dna Adduct In Channel Catfish (Ictalurus Punctatus) After Exposure To 1,2-Dichloroethane., Ahmedin Muktar Jemal Jan 1997

Identification And Quantification Of S-(2-(N(7)-Guanyl)Ethyl)Glutathione Dna Adduct In Channel Catfish (Ictalurus Punctatus) After Exposure To 1,2-Dichloroethane., Ahmedin Muktar Jemal

LSU Historical Dissertations and Theses

The main goal of the study was to provide the basic technical frame work for the use of native fish species as environmental sentinels for potential human exposure to genotoxic agents in general and to 1,2-dichloroethane (ethylene dichloride) in particular. First, LC/MS/ESI/ID and LC/MS/MS/ESI/ID methods for detection and quantification of S- (2-(N$\sp7$-guanyl)ethyl) glutathione DNA adduct from biological samples was developed. The methods were tested by exposing groups of rats with three dose levels of 1,2-dibromoethane. They allowed detection of $\sim$1 adduct in 10$\sp7$ bases. Second, the formation and persistence of DNA adduct in channel catfish (Ictalurus punctatus) from 1,2-dichloroethane exposure …

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Teacher Conceptions And The Curriculum: A Longitudinal, Multicase Study Of College Chemistry Teaching., Charles J. Killebrew Jan 1997

Teacher Conceptions And The Curriculum: A Longitudinal, Multicase Study Of College Chemistry Teaching., Charles J. Killebrew

LSU Historical Dissertations and Theses

Strategic innovations and interventions to reform college science teaching will be required to promote the retention and achievement of those students who might otherwise elect to defect at the entry-level courses. The extent to which this can be achieved will depend upon educational research into ways that the science curriculum can be restructured to accomplish the dual function of enhancing science literacy while promoting recruitment to scientific careers. To explore these issues, four introductory college chemistry classes were observed over a period of two years. The classes were designated either as traditional or conceptual. Selection into these categories was based …

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Activity Of Selected Insecticides Against The Soybean Looper, Pseudoplusia Includens (Walker), Using An Artificial Diet Overlay Bioassay Technique: Dosage Mortality, Discriminating Concentrations, And Resistance Monitoring., Rosanne Nicholson Mascarenhas Jan 1997

Activity Of Selected Insecticides Against The Soybean Looper, Pseudoplusia Includens (Walker), Using An Artificial Diet Overlay Bioassay Technique: Dosage Mortality, Discriminating Concentrations, And Resistance Monitoring., Rosanne Nicholson Mascarenhas

LSU Historical Dissertations and Theses

Diet overlay bioassays were conducted, evaluating insecticides requiring ingestion, on 3rd instar soybean loopers, Pseudoplusia includens (Walker). Laboratory reference and field strains were exposed to several insecticide concentrations, and LC$\sb{50}$s were compared. Field strains had significantly greater LC$\sb{50}$s than the reference strain when evaluating standard insecticides. Bioassays with experimental insecticides revealed few differences among strains. The diet overlay technique appears to be a viable method for monitoring insecticide resistance to these insecticides. Insecticide discriminating concentrations were determined using diet overlay bioassays to evaluate susceptibility of field and F1 generation, laboratory and field soybean looper strains. Field strains, exposed to permethrin …

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Pest Status And Management Of Beet Armyworm, Spodoptera Exigua (Hubner), On Cotton In Louisiana., Victor James Mascarenhas Jan 1997

Pest Status And Management Of Beet Armyworm, Spodoptera Exigua (Hubner), On Cotton In Louisiana., Victor James Mascarenhas

LSU Historical Dissertations and Theses

Field cage studies were conducted to measure the effects of late season beet armyworm, Spodoptera exigua (Hubner), infestations (0, 1, 3, and 6 egg masses per 5.1 row m) on defoliation, fruit damage, and yield of cotton. Light penetration through the canopy was significantly higher in infested plots. Although a trend for increased numbers of damaged fruiting forms with increases in egg mass density was observed, there were no significant differences between infested and control plots. There were no significant differences in the cumulative number of shed fruiting forms or yield between infested and control plots. Field tests were conducted …

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Phylogeny Of The Characeae (Charophyta) And Biogeography Of Chara (Characeae) Inferred From Ribosomal Rna Genes., Susan T. Meiers Jan 1997

Phylogeny Of The Characeae (Charophyta) And Biogeography Of Chara (Characeae) Inferred From Ribosomal Rna Genes., Susan T. Meiers

LSU Historical Dissertations and Theses

This dissertation examined generic, subsection, and infraspecific aspects of the phylogeny of the Characeae, and biogeography of Chara subsections and Chara haitensis. These relationships were inferred from cladistic and maximum likelihood analyses of sequence data for 18S and ITS regions of nuclear-encoded ribosomal RNA genes. Morphologically-based phylogenetic hypotheses of Wood and Imahori (1965) and Khan and Sarma (1984) concerning the six extant members of Characeae were tested. The analyses supported: monophyly of family Characeae, tribe Chareae, and of Lamprothamnium; placement of Nitellopsis basal to tribe Chareae; and an unresolved relationship between Lamprothamnium and Chara. Neither the hypothesis of Wood and …

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Vegetation, Soils, And Hydrology Of Central Louisiana Bottomland Hardwood Forest Types., William Brown Patterson Jan 1997

Vegetation, Soils, And Hydrology Of Central Louisiana Bottomland Hardwood Forest Types., William Brown Patterson

LSU Historical Dissertations and Theses

Wetland delineation in bottomland hardwood forests is controversial due to uncertainty of the duration of inundation and soil saturation on seasonally dry sites. Wetland delineation requires an assessment of hydrophytic vegetation, hydric soils, and wetland hydrology. The objectives were to: (i) classify forest types in five Wildlife Management Areas in central Louisiana within Sharkey clay and Fausse clay soil mapping units, (ii) compare site and soil variables between the forest types, (iii) evaluate relationships between tree species distributions and soil/site factors, (iv) characterize soils in the study area, (v) evaluate differences in forest types for durations of inundation, soil saturation, …

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Metamorphosis Of The Hawaiian Stream Goby Sicyopterus Stimpsoni: A Structural, Functional, And Behavioral Analysis., Heiko Lars Schoenfuss Jan 1997

Metamorphosis Of The Hawaiian Stream Goby Sicyopterus Stimpsoni: A Structural, Functional, And Behavioral Analysis., Heiko Lars Schoenfuss

LSU Historical Dissertations and Theses

The endemic goby Sicyopterus stimpsoni is unique among five species of Hawaiian freshwater fishes because it undergoes rapid metamorphosis of cranial structures during postlarval development. These fishes are amphidromous and return after a prolonged stay in the ocean to streams where they are confined to estuaries until completion of cranial restructuring. Within 48 hours after entering fresh water, head width increases significantly, while total length and head length remains unchanged. Weight decreases by approximately 15% during this period. The upper lip enlarges greatly, and the mouth position shifts from terminal to nearly ventral. Shape analysis of radiographs taken from a …

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Aerenchyma Development In The Freshwater Marsh Species Sagittaria Lancifolia L., Elisabeth Ellen Schussler Jan 1997

Aerenchyma Development In The Freshwater Marsh Species Sagittaria Lancifolia L., Elisabeth Ellen Schussler

LSU Historical Dissertations and Theses

Aerenchyma tissue consists of gas channels that provide a pathway for O$\sb2$ transport to waterlogged roots. Aerenchyma gas spaces are formed by cell separation or cell lysis during development. Light microscopy was used to determine how aerenchyma develops in Sagittaria lancifolia, a freshwater marsh species, when plants were grown in hydroponic solution. Petiole aerenchyma was formed by cell separation caused by differential cell expansion and division. In the root cortex, certain radial files of cells separated slightly from adjacent files and then lysed to form gas spaces. Development of root aerenchyma was characterized in S. lancifolia, Zea mays, and Oryza …

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Development Of Diagnostic Technology For Monitoring Pyrethroid Resistance Mechanisms In The Tobacco Budworm, Heliothis Virescens (F.)., Guomin Shan Jan 1997

Development Of Diagnostic Technology For Monitoring Pyrethroid Resistance Mechanisms In The Tobacco Budworm, Heliothis Virescens (F.)., Guomin Shan

LSU Historical Dissertations and Theses

Metabolic resistance was studied in the tobacco budworm, Heliothis virescens (F.) using pyrethroid analogs, insecticide synergists, and an in vitro assay with $\sp{14}$C-cypermethrin. In initial studies, the phenoxybenzyl moiety of conventional pyrethroid, a major site of oxidative metabolism in resistant H. virescens, was replaced with P450 monooxygenase-inhibiting or oxidatively blocked groups. Isomers (1R/1S, cis/trans) of the resulting chrysanthemates were separated and tested as insecticides against pyrethroid-susceptible (LSU) and -resistant H. virescens (Pyr-R). A number of compounds with pentafluorophenyl (PFP), methylenedioxyphenyl (MDP), and propargyloxyphenyl (PP) groups were insecticidal and activity was dependent on both geometric and stereochemical configuration of the acid …

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The Myth Of Narcissus And The Narcissistic Structure., Joachim Conrad Hermann Vogeler Jan 1997

The Myth Of Narcissus And The Narcissistic Structure., Joachim Conrad Hermann Vogeler

LSU Historical Dissertations and Theses

Since Freud's article "On Narcissism," behavioral psychologists have predominantly viewed this phenomenon as a personality disorder. This dissertation, in contrast, provides a psychoanalytic, i.e., Lacanian reading of the myth of Narcissus as it is recorded in classical literature, and brings about an understanding of the myth's underlying structure. The four fundamental exigencies of the myth's structure include the incest prohibition which symbolically castrates the human subject, the incestuous desire as a result of this prohibition, the displacement of this desire for another imaginary object, and the obsessive quest of that image as the symptom. This structure--defined as narcissistic structure and …

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A Feminist Study Of African American Art In New Orleans: Considerations Of Aesthetics, Art History And Art Criticism., Harriet Joanne Walker Jan 1997

A Feminist Study Of African American Art In New Orleans: Considerations Of Aesthetics, Art History And Art Criticism., Harriet Joanne Walker

LSU Historical Dissertations and Theses

How students are taught to think about what is considered "art" and who are "artists" contributes to their sense of self within the world. It can confine them to accept a system that devalues and excludes or it can inspire them to explore the political dimensions of art, to recognize social contradictions, and to contribute to cultural dialogue. The purpose of this study is to provide content for an art curriculum that develops the intellectual capabilities and broadens the critical consciousness of students. The study of aesthetics, art history, and art criticism offer possibilities for understanding the multiple social, historical, …

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Rickettsia Felis, A Newly Discovered Rickettsia Associated With The Cat Flea (Ctenocephalides Felis Bouche)., Jimmy Wedincamp Jr Jan 1997

Rickettsia Felis, A Newly Discovered Rickettsia Associated With The Cat Flea (Ctenocephalides Felis Bouche)., Jimmy Wedincamp Jr

LSU Historical Dissertations and Theses

A study was performed to determine the life cycle of Rickettsia felis, a novel bacterium associated with cat fleas (Ctenocephalides felis Bouche). Cat flea populations maintain R. felis in successive generations by efficient transovarial transmission. Transovarial transmission was demonstrated in our study up to 12 generations. The mean infection rate for the progeny of fleas maintained on both cats and an artificial membrane system were comparable (64.3% and 58% respectively). Cats with no prior exposure to fleas were exposed to fleas infected with Rickettsia felis and monitored monthly for seroconversion via IFA. Blood samples were assayed for the presence of …

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The Polysaccharide Capsule Of Vibrio Vulnificus: Virulence, Transposon Mutagenesis, And The Identification Of An Essential Gene., Amy Buscher Zuppardo Jan 1997

The Polysaccharide Capsule Of Vibrio Vulnificus: Virulence, Transposon Mutagenesis, And The Identification Of An Essential Gene., Amy Buscher Zuppardo

LSU Historical Dissertations and Theses

The extracellular capsule polysaccharide (CPS) of Vibrio vulnificus is a primary virulence factor which allows survival of the bacteria in the human host. To study the genes involved in the production of the polysaccharide capsule, 23 mutants were generated that lost their ability to produce CPS due to the insertion of a mini-transposon into the genome of the encapsulated clinical strain V. vulnificus 1003 (O). The mutants were examined by Southern blot analysis to ensure the transposon had inserted only once in the chromosome. Exoenzymes, which are believed to contribute to the virulence of the organism, produced by all 23 …

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The Production Of Glucooligosaccharides By Leuconostoc Mesenteroides Atcc 13146 And Lipomyces Starkeyi Atcc 74054., Sun Kyun Yoo Jan 1997

The Production Of Glucooligosaccharides By Leuconostoc Mesenteroides Atcc 13146 And Lipomyces Starkeyi Atcc 74054., Sun Kyun Yoo

LSU Historical Dissertations and Theses

Glucooligosaccharides of less than DP 10 were produced either by mixed cultures of Leuconostoc mesenteroides ATCC 13146 and L. starkeyi ATCC 74054, or by an acceptor reaction produced by Leuconostoc mesenteroides ATCC 13146. The yields of glucooligosaccharides produced by mixed culture and acceptor reaction reached up to 49 and 90% of theoretical yield. The composition of carbohydrates at the end of fermentation by mixed culture was 31.4% oligosaccharides, 17.6% dextran, 31.4% mannitol, 2.1% fructose, and 2.4% of sucrose. The composition of carbohydrates at the end of fermentation by acceptor reaction was 32.7% pannose, 30.4% branched isomaltotetraose (DP 4), 21.7% branched …

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The Compliance-Seeking Process From The Perspective Of The Respondent: The Role Of Goals In Responses To Requests., Barbara L. Woods Jan 1997

The Compliance-Seeking Process From The Perspective Of The Respondent: The Role Of Goals In Responses To Requests., Barbara L. Woods

LSU Historical Dissertations and Theses

This study examined compliance seeking from the perspective of recipients of direct requests with respect to types of responses, goals, liking, and locus of control. A total of 211 employed adults completed a survey that included responses to hypothetical request scenarios involving liked and disliked co-workers, measures of goals factors, and a measure of locus of control. Six types of responses were identified: simple agreement, elaborated agreement, simple refusal, refusal with reasons, request more information, and postpone decision. Participants reported a tendency to agree with requests, regardless of liking. Factor analyses revealed three-factor models for the liked and disliked conditions. …

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Fluorescence Lifetime Discrimination Of Near-Infrared Dye-Labeled Oligonucleotide Fragments Separated By Capillary Gel Electrophoresis For Base-Calling Applications In Dna Sequencing., Benjamin Leighton Legendre Jr Jan 1997

Fluorescence Lifetime Discrimination Of Near-Infrared Dye-Labeled Oligonucleotide Fragments Separated By Capillary Gel Electrophoresis For Base-Calling Applications In Dna Sequencing., Benjamin Leighton Legendre Jr

LSU Historical Dissertations and Theses

The research presented in this dissertation involves the construction of a near-infrared time-correlated single photon counting system which utilizes a mode-locked Ti:sapphire or pulsed diode laser as the excitation source and single photon avalanche diode as the photodetector and the subsequent study of two simple algorithms, the Maximum Likelihood Estimator (MLE) and the Rapid Lifetime Determination (RLD) methods, for fluorescence lifetime determination. The purpose of this research is to aid in the development of a low cost, highly efficient, and high throughput device for DNA sequencing which utilizes near-IR fluorophores which have similar absorption and emission properties but possess unique …

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A Search For Biologically Active Phytochemicals From Endemic Plants Of The Southeastern United States., Steven Lynn Robbs Jan 1997

A Search For Biologically Active Phytochemicals From Endemic Plants Of The Southeastern United States., Steven Lynn Robbs

LSU Historical Dissertations and Theses

In an investigation of allelopathy in the Florida scrub, bioassays with terpenes were performed against: Lactuca sativa, Rudbeckia hirta, Leptochloa dubia and Schizachyrium scoparium. Cineole was phytotoxic against Rudbeckia at 17 ppm and Lactuca at 165 ppm. (S)-camphor was phytotoxic to Rudbeckia at 1 ppm, Lactuca at 28 ppm, and Leptochloa and Schizachyrium at 134 ppm. (R)-Camphor, myrtenol and myrtenal were phytotoxic against Rudbeckia at concentrations of 28, 25 and 15 ppm respectively. Farnesol stimulated the germination of Schizachyrium at concentrations up to 50 ppm and at 100 ppm it reduced the radicle length of all test species. Geraniol stimulated …

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Synthesis Of Monodisperse Poly(Gamma-Benzyl-Alpha,L-Glutamate) Oligomers And Their Star-Shaped Derivatives., Xiaolan Wang Jan 1997

Synthesis Of Monodisperse Poly(Gamma-Benzyl-Alpha,L-Glutamate) Oligomers And Their Star-Shaped Derivatives., Xiaolan Wang

LSU Historical Dissertations and Theses

Poly($\gamma$-benzyl-$\alpha$,L-glutamate), PBLG, is a widely studied example of polypeptides. The preparation of monodisperse samples of PBLG and PBLG oligomer is difficult to achieve. In this work we probe the possibility of preparation of PBLG oligomers by polymerization of L-glutamic acid N-carboxyanhydride (NCA) with different initiators such as primary amine, sterically hindered secondary amine, tertiary amine, and strong base. Information regarding molecular weight distribution of these oligomers was obtained by applying MALDI-TOF mass spectrometry and reversed phase HPLC. While some researchers reported that application of primary amine initiators or polar solvents such as DMF could improve the molecular weight distributions of …

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Causes Of Vegetation Dieback And Subsequent Wetland Loss In Two Louisiana Coastal Marshes., Eric Courtney Webb Jan 1997

Causes Of Vegetation Dieback And Subsequent Wetland Loss In Two Louisiana Coastal Marshes., Eric Courtney Webb

LSU Historical Dissertations and Theses

Vegetation dieback is an important component of the wetland loss process in coastal Louisiana. To determine the factors causing vegetation dieback in a Louisiana salt marsh and oligohaline marsh, field monitoring and manipulative field experiments were conducted in both marsh types. In the salt marsh, a three-year field study was conducted in which biotic and edaphic characteristics were measured and the effect of elevation on four salt marsh plant species was tested in a manipulative field experiment. In the oligohaline marsh, a two-year field study was conducted which evaluated the relationship between biotic and edaphic characteristics. Additionally, the effects of …

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Caprine Sperm Cells As Vectors For Gene Transfer., Yongxin Sun Jan 1997

Caprine Sperm Cells As Vectors For Gene Transfer., Yongxin Sun

LSU Historical Dissertations and Theses

Goat sperm cells were used as a model to evaluate sperm-mediated gene transfer. Fresh and frozen-thawed goat sperm cells were co-incubated with radio-labelled foreign DNA. After 10 extensive washings, the compacted sperm retained foreign DNA. Confocal microscopy confirmed that the position on the sperm cell responsible for binding of foreign DNA was located in both the anterior and the posterior heads of caprine sperm cells. Furthermore, confocal longitudinal sections of the sperm cells showed that foreign DNA had penetrated into goat sperm nuclei. In this study, 37% of the fresh goat sperm and 33% of the frozen-thawed goat sperm cells …

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Efficient Mapping Of Neural Network Models On A Class Of Parallel Architectures., Behnam Seyed Arad Jan 1997

Efficient Mapping Of Neural Network Models On A Class Of Parallel Architectures., Behnam Seyed Arad

LSU Historical Dissertations and Theses

This dissertation develops a formal and systematic methodology for efficient mapping of several contemporary artificial neural network (ANN) models on k-ary n-cube parallel architectures (KNC's). We apply the general mapping to several important ANN models including feedforward ANN's trained with backpropagation algorithm, radial basis function networks, cascade correlation learning, and adaptive resonance theory networks. Our approach utilizes a parallel task graph representing concurrent operations of the ANN model during training. The mapping of the ANN is performed in two steps. First, the parallel task graph of the ANN is mapped to a virtual KNC of compatible dimensionality. This involves decomposing …

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