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Evolutionary Implications Of Divergent Clines In An Avian (Manacus: Aves) Hybrid Zone, Robb T. Brumfield, Robert W. Jernigan, David B. Mcdonald, Michael J. Braun Jan 2001

Evolutionary Implications Of Divergent Clines In An Avian (Manacus: Aves) Hybrid Zone, Robb T. Brumfield, Robert W. Jernigan, David B. Mcdonald, Michael J. Braun

Faculty Publications

A previous study of the hybrid zone in western Panama between white-collared (Manacus candei) and golden-collared manakins (M. vitellinus) documented the unidirectional introgression of vitellinus male secondary sexual traits across the zone. Here, we examine the hybrid zone in greater genetic and morphological detail. Statistical comparisons of clines are performed using maximum-likelihood and nonparametric bootstrap methods. Our results demonstrate that an array of six molecular and two morphometric markers agree in cline position and width. Clines for male collar and belly color are similar in width to the first eight clines, but are shifted in position by at least five …

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Sexual Selection On Plumage And Behavior In An Avian Hybrid Zone: Experimental Tests Of Male-Male Interactions, David B. Mcdonald, Robert P. Clay, Robb T. Brumfield, Michael J. Braun Jan 2001

Sexual Selection On Plumage And Behavior In An Avian Hybrid Zone: Experimental Tests Of Male-Male Interactions, David B. Mcdonald, Robert P. Clay, Robb T. Brumfield, Michael J. Braun

Faculty Publications

In western Panama, an unusual hybrid zone exists between white-collared manakins, Manacus candei, and golden-collared manakins, M. vitellinus. Unidirectional introgression of plumage traits from vitellinus into candei has created a region in which all definitively plumaged males have a collar that is lemon-colored. These males are nearly indistinguishable from white-collared candei genetically and morphometrically, but strongly resemble golden-collared vitellinus due to the introgression of secondary sexual plumage traits, particularly the lemon-colored collar. The introgression could be explained by sexual selection for golden-collared traits or by a series of mechanisms that do not invoke sexual selection (e.g., neutral diffusion, dominant allele). …

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Membrane Lipid Biosynthesis In Chlamydomonas Reinhardtii. In Vitro Biosynthesis Of Diacylglyceryltrimethylhomoserine, T. S. Moore, Z. Du, Z. Chen Jan 2001

Membrane Lipid Biosynthesis In Chlamydomonas Reinhardtii. In Vitro Biosynthesis Of Diacylglyceryltrimethylhomoserine, T. S. Moore, Z. Du, Z. Chen

Faculty Publications

Diacylglyceryltrimethylhomo-Ser (DGTS) is an abundant lipid in the membranes of many algae, lower plants, and fungi. It commonly has an inverse concentration relationship with phosphatidylcholine, thus seemingly capable of replacing this phospholipid in these organisms. In some places this replacement is complete; Chlamydomonas reinhardtii is such an organism, and was used for these investigations. We have assayed headgroup incorporation to form DGTS in vitro. The precursor for both the homo-Ser moiety and the methyl groups was found to be S-adenosyl-L-Met. DGTS formation was associated with microsomal fractions and is not in plastids. By analogy with phosphatidylcholine and phosphatidylethanolamine biosynthesis in …

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Sweetpotato Periderm Components Inhibit In Vitro Growth Of Root Rotting Fungi, Jr Harrison, J. K. Peterson, C. A. Clark, M. E. Snook Jan 2001

Sweetpotato Periderm Components Inhibit In Vitro Growth Of Root Rotting Fungi, Jr Harrison, J. K. Peterson, C. A. Clark, M. E. Snook

Faculty Publications

Sweetpotato [Ipomoea batatas (L.) Lam.] periderm components were tested for their effect on four fungi that infect sweetpotato roots: Fusarium oxysporum Schlecht. f. sp. batatas (Wollenw.) Snyd. & Hans. and F. solani (Sacc.) Mart., both of which cause stem and root disease; and Lasiodiplodea theobromae (Pat.) Griffon & Maubl. and Rhizopus stolonifer (Ehr. ex Fr.) Lind., both of which cause storage root disease. Sequential extracts of 'Regal' sweetpotato periderm with hexane, methanol, and 50% methanol were inhibitory to the four fungi when incorporated into potato dextrose agar medium in petri dish bioassays. The methanol and 50% methanol extracts were much …

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Effect Of Commercial Fat Replacers On The Microstructure Of Low-Fat Cheddar Cheese, Kayanush J. Aryana, Zahur U. Haque Jan 2001

Effect Of Commercial Fat Replacers On The Microstructure Of Low-Fat Cheddar Cheese, Kayanush J. Aryana, Zahur U. Haque

Faculty Publications

This objective of this study was to determine the effect of protein-and carbohydrate-based fat replacers on the microstructure of low-fat Cheddar cheese. Microstructure was studied by transmission and scanning electron microscopy. Protein-based fat replacers were Dairy LoTM (DL) and SimplesseTM (SIMP), while the carbohydrate-based fat replacers were NovagelTM (NOV) and StellarTM (STEL). Low-fat Cheddar cheese was manufactured using these commercial fat replacers and aged for 6 months at 5 °C. Low-fat control (LFC) and low-fat Cheddar cheese made with SIMP and DL showed a rippled surface microstructure while incorporation of NOV and STEL resulted in cheese with an undulated and …

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Linkage And Association Analysis Of Angiotensin I-Converting Enzyme (Ace)-Gene Polymorphisms With Ace Concentration And Blood Pressure, Xiaofeng Zhu, Nourdine Bouzekri, Lorraine Southam, Richard S. Cooper, Adebowale Adeyemo, Colin A. Mckenzie, Amy Luke, Guangjie Chen, Robert C. Elston, Ryk Ward Jan 2001

Linkage And Association Analysis Of Angiotensin I-Converting Enzyme (Ace)-Gene Polymorphisms With Ace Concentration And Blood Pressure, Xiaofeng Zhu, Nourdine Bouzekri, Lorraine Southam, Richard S. Cooper, Adebowale Adeyemo, Colin A. Mckenzie, Amy Luke, Guangjie Chen, Robert C. Elston, Ryk Ward

Faculty Publications

Considerable effort has been expended to determine whether the gene for angiotensin I-converting enzyme (ACE) confers susceptibility to cardiovascular disease. In this study, we genotyped 13 polymorphisms in the ACE gene in 1,343 Nigerians from 332 families. To localize the genetic effect, we first performed linkage and association analysis of all the markers with ACE concentration. In multipoint variance-component analysis, this region was strongly linked to ACE concentration (maximum LOD score 7.5). Likewise, most of the polymorphisms in the ACE gene were significantly associated with ACE (P < .0013). The two most highly associated polymorphisms, ACE4 and ACE8, accounted for 6% and 19% of the variance in ACE, respectively. A two-locus additive model with an additive x additive interaction of these polymorphisms explained most of the ACE variation associated with this region. We next analyzed the relationship between these two polymorphisms (ACE4 and ACE8) and blood pressure (BP). Although no evidence of linkage was detected, significant association was found for both systolic and diastolic BP when a two-locus additive model developed for ACE concentration was used. Further analyses demonstrated that an epistasis model provided the best fit to the BP variation. In conclusion, we found that the two polymorphisms explaining the greatest variation in ACE concentration are significantly associated with BP, through interaction, in this African population sample. Our study also demonstrates that greater statistical power can be anticipated with association analysis versus linkage, when markers in strong linkage disequilibrium with a trait locus have been identified. Furthermore, alllelic interaction may play an important role in the dissection of complex traits such as BP.

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Effect Of Sweetpotato Genotype, Storage Time And Production Site On Feeding And Oviposition Behavior Of The Sweetpotato Weevil, Cylas Formicarius (Coleoptera: Apoinidae), L. Mao, R. N. Story, A. M. Hammond, D. R. Labonte Jan 2001

Effect Of Sweetpotato Genotype, Storage Time And Production Site On Feeding And Oviposition Behavior Of The Sweetpotato Weevil, Cylas Formicarius (Coleoptera: Apoinidae), L. Mao, R. N. Story, A. M. Hammond, D. R. Labonte

Faculty Publications

The effect of sweetpotato genotype, storage time and production site on Cylas formicarius (Fab.) feeding and oviposition was investigated. Sweetpotato genotype had a significant effect on feeding and oviposition rates in both no-choice and choice arenas. Beauregard and Centennial were uniformly susceptible across all age groups. W-250 had the least number of feeding punctures and eggs at 7 and 25 days after harvest. At 85 days after harvest, W-244 had the least number of feeding punctures and eggs, while W-250 was not significantly different from Beauregard and Centennial. Roots of the same genotype grown in different locations differed in the …

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The Asymptotic Equivalence Of The Fisher Information Matrices For Type I And Type Ii Censored Data From Location-Scale Families, Luis A. Escobar, William Q. Meeker Jan 2001

The Asymptotic Equivalence Of The Fisher Information Matrices For Type I And Type Ii Censored Data From Location-Scale Families, Luis A. Escobar, William Q. Meeker

Faculty Publications

Type I and Type II censored data arise frequently in controlled laboratory studies concerning time to a particular event (e.g., death of an animal or failure of a physical device). Log-location-scale distributions (e.g., Weibull, log-normal, and loglogistic) are commonly used to model the resulting data. Maximum likelihood (ML) is generally used to obtain parameter estimates when the data are censored. The Fisher information matrix can be used to obtain large-sample approximate variances and covariances of the ML estimates or to estimate these variances and covariances from data. The derivations of the Fisher information matrix proceed differently for Type I (time …

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Similarity Is Relative: Hierarchy Of Genetic Similarities In The Formosan Subterranean Termite (Isoptera: Rhinotermitidae) In Hawaii, C. Husseneder, J. K. Grace Jan 2001

Similarity Is Relative: Hierarchy Of Genetic Similarities In The Formosan Subterranean Termite (Isoptera: Rhinotermitidae) In Hawaii, C. Husseneder, J. K. Grace

Faculty Publications

Termites (Isoptera) have a strong hierarchical structure due to their social organization. To interpret genetic differences within and among termite populations it is first necessary to create a quantitative scale to determine the meaning of "different." To accomplish this, the entire hierarchy of genetic similarities in a Hawaiian population of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) was defined by multilocus DNA fingerprinting using the oligonucleotide (GTG)5 as a probe. The genetic background similarity in the population, based on the genetic similarity between unrelated termites, was 0.21 and falls in the range of other natural invertebrate and vertebrate populations. The mean genetic …

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Seasonal Distribution And Parasitism Of Scapteriscus Spp. (Orthoptera: Gryllotalpidae) In Southeastern Louisiana, D. C. Henne, S. J. Johnson Jan 2001

Seasonal Distribution And Parasitism Of Scapteriscus Spp. (Orthoptera: Gryllotalpidae) In Southeastern Louisiana, D. C. Henne, S. J. Johnson

Faculty Publications

Mole crickets of the genus Scapteriscus were accidentally introduced into the southern United States almost a century ago and are considered to be economically important pests in southern U.S. regions. Mole crickets were sampled using acoustic traps in Baton Rouge and New Orleans, Louisiana in the fall of 1998, the spring and fall of 1999, and the spring of 2000. In southeastern Louisiana Scapteriscus borellii has a seasonal flight period starting in late February and continuing into June. A lesser flight period occurs in the fall, starting in mid-September and continuing into November. S. vicinus was captured only from late …

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Lsu General Catalog 2001-2002, Louisiana State University And Agricultural And Mechanical College Jan 2001

Lsu General Catalog 2001-2002, Louisiana State University And Agricultural And Mechanical College

LSU General Catalog

The LSU General Catalog describes all undergraduate and graduate departments and programs with degree requirements and courses offered for each one. The General Catalog includes information on registration and financial aid as well as academic services offered to all students.

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Selection, Egg Viability, And Fecundity Of The Sugarcane Borer (Lepidoptera: Crambidae) With Tebufenozide, L. M. Rodriguez, J. A. Ottea, T. E. Reagan Jan 2001

Selection, Egg Viability, And Fecundity Of The Sugarcane Borer (Lepidoptera: Crambidae) With Tebufenozide, L. M. Rodriguez, J. A. Ottea, T. E. Reagan

Faculty Publications

Two separate attempts to select the sugarcane borer, Diatraea saccharalis (F.), for resistance to tebufenozide were unsuccessful. Both selected colonies were lost after the fourth generation due to a lack of oviposition. Differences were not detected in fecundity or percent egg viability for 5-d-old third instars exposed to concentrations (EC5, EC15, and EC30) of tebufenozide for 7 d. Decreases (P ≤ 0.01) in mean female pupal weights were detected in larvae exposed to EC15 and EC30 concentrations. An ovicidal impact using serial dilutions of tebufenozide (10, 100, and 200 ppm) also was detected. Percent viability was reduced from 98% for …

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Greeks, Indians, And The Scotticsh Presbyterian Dissident Arguments For Vegetarianism In Enlightenment Scotland, David Allen Jan 2001

Greeks, Indians, And The Scotticsh Presbyterian Dissident Arguments For Vegetarianism In Enlightenment Scotland, David Allen

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

No abstract provided.

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Book Reviews Jan 2001

Book Reviews

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

No abstract provided.

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Do We Know What We Think We Know About Winter Ranges Of Migrants To South America? The Case Of The Veery (Catharus Fuscescens), P. C. Stouffer Jan 2001

Do We Know What We Think We Know About Winter Ranges Of Migrants To South America? The Case Of The Veery (Catharus Fuscescens), P. C. Stouffer

Faculty Publications

No abstract provided.

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Differential Detection Of Bartonella Species And Strains In Cat Scratch Disease Diagnostics By Polymerase Chain Reaction Amplification Of 16s Ribosomal Rna Gene, Ronald A. Tapp, Alma F. Roy, Richard E. Corstvet, Vincent L. Wilson Jan 2001

Differential Detection Of Bartonella Species And Strains In Cat Scratch Disease Diagnostics By Polymerase Chain Reaction Amplification Of 16s Ribosomal Rna Gene, Ronald A. Tapp, Alma F. Roy, Richard E. Corstvet, Vincent L. Wilson

Faculty Publications

Cat scratch disease (CSD) has been difficult to diagnose in animals because of the protracted clinical course of infection and the quiescent phases when the microbial culprit lies dormant. The causative agent in CSD appears to be multiple species and strains of Bartonella. Using polymerase chain reaction (PCR) techniques for amplification of highly variable regions of the 16S ribosomal RNA (rRNA) gene sequence, a very sensitive species- and strain-specific assay for CSD-causing Bartonella species was developed. PCR primers were designed to specifically amplify the 16S rRNA gene of Bartonella species but not of other microbial pathogens. This initial PCR was …

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The Influence Of A Court Appointed Special Advocate On The Length Of Time In Out -Of -Home Care., Nancy Loker Hart Jan 2001

The Influence Of A Court Appointed Special Advocate On The Length Of Time In Out -Of -Home Care., Nancy Loker Hart

LSU Historical Dissertations and Theses

The purpose of this study was to determine the influence of participation in a CASA child advocacy program on the length of time in out-of-home placement among children in foster care. Two groups of children, one group having a CASA volunteer, and the other not having a CASA volunteer, were compared on selected characteristics. Also, this study sought to determine if a model existed that explains a significant portion of the variance in the length of time in out-of-home placement among children in foster care. The demographic information analyzed was obtained using recorded information from the computerized files of the …

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An Improved In Vitro Model For The Study Of Mycobacterium Leprae/Schwann Cell Interactions, Deanna Alisa Hagge Jan 2001

An Improved In Vitro Model For The Study Of Mycobacterium Leprae/Schwann Cell Interactions, Deanna Alisa Hagge

LSU Doctoral Dissertations

Globally, millions of leprosy patients suffer irreversible peripheral nerve damage resulting in blindness or other disabilities as a consequence of Mycobacterium leprae infection. Schwann cells, the neural target of M. leprae, have a central role in leprosy histopathology including axonotrophy, altered myelin architecture and demyelination. The mechanisms of nerve damage have not been fully elucidated but appear to be the direct result of M. leprae within Schwann cells or a combined effect with an aggressive immune response to M. leprae within the nerves. There is no standardized in vitro model for the study of M. leprae interactions with the Schwann …

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Effects Of Water Color On Food Web Structure In Freshwater Lakes, Bjoern Wissel Jan 2001

Effects Of Water Color On Food Web Structure In Freshwater Lakes, Bjoern Wissel

LSU Doctoral Dissertations

Water color has multiple effects on freshwater lakes, changing the vertical profiles of light, temperature, and oxygen. Therefore, increased water color should reduce planktivory by visually guided fish, but invertebrate predators such as Chaoborus should become more important. Since fish prefer larger prey but Chaoborus can only ingest smaller zooplankton, increased water color should cause a shift from small to large zooplankton species. To test this hypothesis, I analyzed two lake data sets to examine how water color affects the relative importance of fish and Chaoborus as planktivores. Subsequently, I studied the vertical migration behavior of the zooplankton prey in …

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Developing Consensus Indicators Of Sustainability For Southeastern United States Aquaculture, Rex H. Caffey Jan 2001

Developing Consensus Indicators Of Sustainability For Southeastern United States Aquaculture, Rex H. Caffey

LSU Agricultural Experiment Station Reports

No abstract provided.

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Effects Of Immigrant Status On Mexicans In The United States, Michelle Monique Balan Jan 2001

Effects Of Immigrant Status On Mexicans In The United States, Michelle Monique Balan

LSU Master's Theses

This thesis analyzes the relationship between immigration and mental health. I used data from a health and migration study of Mexican immigrant women in a Houston community. I found a statistically significant negative relationship between family social support and feelings of depression. Thus, family social support may have buffered some harmful effects of immigrating to the United States. However, I found inconsistent results with labor market variables that may be due to a measurement problem. Both employment variables were statistically significant (p<.05) for models (predictor, predictor and control) including loss of interest and these variables remained significant after control variables were added. Unfortunately, only one of the work variables--the number of months the respondent worked--was in the predicted direction. Contrary to expectations, the other employment variable (ever worked) was negatively related to a loss of interest in previously pleasurable activities.

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The Evaluation Of Pcr-Based Techniques For The Detection Of Fecal Indicator Organisms In Environmental Samples, Quinesha Laticia Perry Jan 2001

The Evaluation Of Pcr-Based Techniques For The Detection Of Fecal Indicator Organisms In Environmental Samples, Quinesha Laticia Perry

LSU Master's Theses

Escherichia coli is the indicator organism of choice for the detection of fecal contamination. Standard methods for detecting fecal contamination often rely on detecting fecal coliforms. While this practice if highly efficient in most applications, when used with the sediment-laden waters of Louisiana, free-living soil bacteria, such as Klebsiella pneumoniae were shown to inflate the fecal coliform counts. An accurate assessment of the contamination problem requires methods that detect E. coli. To detect E. coli, several of species-specific genes were tested before the gadAB genes were selected. The polymerase chain reaction (PCR) was chosen to detect these genes using a …

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Polyurethane Foam Based Packing Media For Biofilters Removing Volatile Organic Compounds From Contaminated Air, Felipe A. Martinez Jan 2001

Polyurethane Foam Based Packing Media For Biofilters Removing Volatile Organic Compounds From Contaminated Air, Felipe A. Martinez

LSU Master's Theses

In recent years, biofiltration technology has gained acceptance worldwide as an economical and reliable air pollution control technology for treating gases contaminated by low concentrations of biodegradable volatile organic compounds (VOCs). Important applications include control of odors generated by wastewater treatment plants and control of VOC emissions from industrial sources. Although there have been many successful applications, several operational problems have been reported in the literature. These include difficulty in control over bed moisture content, high head loss caused by excessive biomass production, and inability to maintain removal efficiency during transient periods of high concentration loading. Use of a superior …

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Evaluation Of In Situ Bioremediation Approaches In Meeting International Standards For Organic And Residual Metals Toxicity In Soils, Jason Allan Mcdonald Jan 2001

Evaluation Of In Situ Bioremediation Approaches In Meeting International Standards For Organic And Residual Metals Toxicity In Soils, Jason Allan Mcdonald

LSU Master's Theses

Drilling fluids and muds are an essential component of the rotary drilling process used to drill for oil and gas on land and in offshore environments. However, the bioaccumulation of petroleum contaminated soils/drilling mud due to oil and natural gas exploration has posed a major environmental concern due to its prolonged environmental persistence and its leachability below the rhizosphere. The main objectives of this research were: (i) To assess initial toxicity of drilling mud and related contaminated soils from an agricultural setting in Galliano, Sicily (Phase one) and (ii) To develop a low intervention bioremediation approach using bioplug technology to …

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Palm Community Development And Influence On Seedling Establishment In A Tropical Moist Forest, Panama, Krista Lynn Farris Lopez Jan 2001

Palm Community Development And Influence On Seedling Establishment In A Tropical Moist Forest, Panama, Krista Lynn Farris Lopez

LSU Master's Theses

Plants often modify microsite conditions important for seedling establishment. Palms may reduce light levels and produce deep leaf litter; both may suppress seedlings, affecting the local abundance, distribution, and species composition of tree seedlings. The abundance and composition of palms were examined along a tropical forest chronosequence at the Barro Colorado Nature Monument, Panama. Palms were sampled along transects in secondary (20, 40, 70, and 100 y in fallow) and old-growth forests. Palm abundance and basal area significantly increased with forest age. Palm distribution was driven by the most abundant palm, Oenocarpus mapora, which accounted for 60% of the total …

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Synthesis And Analysis Of Three-Dimensional Molecular Architectures, Patricia Beck Jan 2001

Synthesis And Analysis Of Three-Dimensional Molecular Architectures, Patricia Beck

LSU Master's Theses

The use of resorcinarenes in the study of biologically significant phenomena has been the focus of much attention, due to the versatility of these macrocyclic compounds. In this thesis, two applications of resorcinarenes are explored. First, the search for the mechanism by which tetraarylboronic acid resorcinarenes lead to colorimetric detection and quantization of saccharide analyte concentration in solution is described. Second, the extension of the lower rim conjugation of the resorcinarene macrocycle by the fourfold addition of various length oligo(p-phenylene) rods is discussed. The synthesis of these tubular materials, with potential uses as artificial ion channels and for binding and …

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Microhabitat Use In An Assemblage Of Native And Introduced Stream Fishes In Wailoa Stream, Island Of Hawaii, Mark G. Mcrae Jan 2001

Microhabitat Use In An Assemblage Of Native And Introduced Stream Fishes In Wailoa Stream, Island Of Hawaii, Mark G. Mcrae

LSU Master's Theses

To date, most research on the ecology of Hawaiian stream fishes has taken place in the middle and upper reaches of streams. In the terminal reaches of streams in Hawaii, the ecological aspects of the relatively more diverse fish assemblages are largely unknown. This study investigated patterns of microhabitat use in an assemblage of native and introduced stream fishes living in the terminal reach of Wailoa Stream on the Island of Hawaii. Multivariate and univariate analyses of microhabitat data collected through underwater visual surveys indicated that differences in microhabitat preferences were an important factor in the structure of this assemblage. …

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Age At Death In The Human Skeleton: A Combined Analysis Of Four Phase-Based Aging Systems To Determine Effieciency And Accuracy In Multifactorial Age Range Assignments, Jennifer Carol Giesecke Jan 2001

Age At Death In The Human Skeleton: A Combined Analysis Of Four Phase-Based Aging Systems To Determine Effieciency And Accuracy In Multifactorial Age Range Assignments, Jennifer Carol Giesecke

LSU Master's Theses

Analyses of human skeletal remains by physical anthropologists necessitate precise methods for the determination of age at death. Physical anthropologists recognize that the most accurate estimations of age at death are produced from evaluation of multiple indicators of age. To this end, three skeletal sites, the auricular surface, pubic symphysis, and right fourth sternal rib end, are often evaluated for age in adult skeletal remains. However, as of yet, no standardized method of combining the respective estimates of age provided at these sites has been reported. The above mentioned skeletal sites of 49 females and 77 males from the Hamann-Todd …

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Isolation And Characterization Of A Rhodobacter Capsulatus Hemc Mutant., Karen Coleman Sullivan Jan 2001

Isolation And Characterization Of A Rhodobacter Capsulatus Hemc Mutant., Karen Coleman Sullivan

LSU Historical Dissertations and Theses

Rhodobacter capsulatus, a purple, nonsulfur photosynthetic bacterium, uses the tetrapyrrole pathway to synthesize four end products: heme, bacteriochlorophyll, vitamin B12, and siroheme. This laboratory has focused on the regulation of the common pathway leading from aminolevulinate to protoporphyrin IX in R. capsulatus. The common portion of the pathway is regulated up to 100-fold by changes in oxygen tension. Research on the regulation of this pathway has been hampered due to a lack of mutants. Until now, the only mutants isolated which block heme production are hemA mutants, which lack aminolevulinate synthase. Since R. capsulatus lacks a cytochrome-independent growth mechanism, mutations …

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Improved Matrix-Assisted Laser Desorption/Ionization Linear Time-Of-Flight Mass Spectrometry Of Oligonucleotides And Nucleic Acids Via Matrix Additives And Sample Preparatory Technique., Tracey Arlene Simmons Jan 2001

Improved Matrix-Assisted Laser Desorption/Ionization Linear Time-Of-Flight Mass Spectrometry Of Oligonucleotides And Nucleic Acids Via Matrix Additives And Sample Preparatory Technique., Tracey Arlene Simmons

LSU Historical Dissertations and Theses

There are two prominent problems recurrent during matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of oligonucleotides: cation adduction and low molecular ion stability. It has been found that the use of organic base solutions of high gas-phase proton affinity, as used previously in electrospray ionization mass spectrometry (ESI-MS), can significantly reduce the cation adduction problem during MALDI-MS. It is proposed that the organic base solutions compete with alkali metal cations for binding to the phosphodiester backbone of the oligonucleotide upon transfer into the gas phase. A comparison of the utility of adding an organic base solution, such as imidazole, triethylamine …

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