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Evaluation Of Management Practices And Remediation Techniques For Improving Water Quality In Agricultural Systems, Theophilus Kene Udeigwe Jan 2008

Evaluation Of Management Practices And Remediation Techniques For Improving Water Quality In Agricultural Systems, Theophilus Kene Udeigwe

LSU Doctoral Dissertations

Surface water quality impairment is often associated with agricultural activities. In this study, the effects of three sugarcane residue management techniques, namely burning (BR), shredding (SR), and retention (RR) of residues on: surface water quality, carbon export, and chemical composition of organic matter in the runoff sediments were characterized. Separate studies were conducted to evaluate predictive relationships for biochemical oxygen demand (BOD) in agricultural effluents, and the effectiveness of bauxite residues (red and brown muds) in reducing soluble nutrient/pollutant release from manure-impacted soils. All the selected water quality parameters were determined using EPA-approved analytical methods. The RR technique exported lower …

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Assessment Of Oxygen Sources And Sinks In The Northern Gulf Of Mexico Using Stable Oxygen Isotopes, Zoraida Jazmin Quinones-Rivera Jan 2008

Assessment Of Oxygen Sources And Sinks In The Northern Gulf Of Mexico Using Stable Oxygen Isotopes, Zoraida Jazmin Quinones-Rivera

LSU Doctoral Dissertations

Coastal hypoxia (< 2 mg O2L-1) represents a global problem that continues to worsen as nutrient fluxes to these areas increase. The second largest zone of human-induced hypoxia is located on the Louisiana continental shelf where hypoxic bottom waters commonly occur during summertime. This region is strongly impacted by the large flux of freshwater and nutrients from the Mississippi River, which influences both biological and physical processes that control oxygen dynamics. Yet, based on oxygen concentration measurements alone, it is difficult to separate the effects of biological factors from physical factors. To address this problem, I used a dual budget approach to assess the importance of oxygen sources and sinks on the Louisiana continental shelf. The dual budget was based on using stable oxygen isotopes (ä18O) in combination with conventional oxygen concentration measurements. To analyze temporal trends, surface and bottom water samples were collected monthly between July 2001 and July 2003 along an onshore-offshore transect. For better spatial resolution, shelfwide sampling was conducted extending from the Mississippi River Delta to the Louisiana-Texas border in the month of July of 2001, 2002, and 2003. Oxygen saturations values ranged between 180% at the surface and almost 0% close to the bottom with a corresponding range of ä18O values from 15‰ to 50‰. Biological parameters were important during all seasons for surface oxygen dynamics. The effects of physical factors were less apparent, except during severe physical disturbances. Bottom water oxygen dynamics showed clear seasonal signals of high oxygen depletion and larger contributions of benthic respiration during the summer, which corresponded to the strong stratification of the water column. In bottom waters, summer oxygen depletion was predominantly due to benthic respiration, accounting for about 73%, 80% and 60% of the total oxygen loss for 2001, 2002 and 2003 respectively. Model estimates of production/respiration (P/R) ratio during the July shelfwide cruises indicated that surface waters were productive with an average calculated P/R above 1. Depth stratified sampling (5 m intervals), which started in July 2002, showed that productivity in the mixed layer (5 to 10 m) was not homogeneous. Calculated P/R exceeded 1 only in the surface layer, while at 5 m P/R was approximately 1 and at a depth of 10 m, P/R was less than 1. Additionally, hypoxic conditions were only detected within 5 m of the bottom sediments. The dual budget approach yielded new estimates of productivity dynamics in surface waters and of sediment oxygen demand in bottom waters. For the first time, this study provided routine insight into productivity and respiration dynamics over large temporal and spatial scales. This could not have been accomplished using traditional methods because they commonly rely on time-consuming incubations. The study has shown that respiration dynamics in bottom waters vary seasonally with higher contribution of benthic respiration during stratified summer conditions and prevalent water column respiration during fall and winter. In contrast, seasonality in surface waters was less pronounced as productivity was more dependent on (salinity-inferred) nutrient supply than climatic forcing.

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Dynamic Workflow Management For Large Scale Scientific Applications, Emir Mahmut Bahsi Jan 2008

Dynamic Workflow Management For Large Scale Scientific Applications, Emir Mahmut Bahsi

LSU Master's Theses

The increasing computational and data requirements of scientific applications have made the usage of large clustered systems as well as distributed resources inevitable. Although executing large applications in these environments brings increased performance, the automation of the process becomes more and more challenging. The use of complex workflow management systems has been a viable solution for this automation process. In this thesis, we study a broad range of workflow management tools and compare their capabilities especially in terms of dynamic and conditional structures they support, which are crucial for the automation of complex applications. We then apply some of these …

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Replication Of Viruses Responsible For Sweet Potato Virus Disease In Resistant And Susceptible Sweepotato Genotypes And Identification Of Molecular Markers Linked To Resistance, Douglas Watuku Miano Jan 2008

Replication Of Viruses Responsible For Sweet Potato Virus Disease In Resistant And Susceptible Sweepotato Genotypes And Identification Of Molecular Markers Linked To Resistance, Douglas Watuku Miano

LSU Doctoral Dissertations

Virus diseases are a major constraint to sweetpotato production in East Africa. The most important is the Sweet potato virus disease (SPVD), a result of co-infection of Sweet potato chlorotic stunt virus (SPCSV) and Sweet potato feathery mottle virus (SPFMV). Studies were done on different aspects of resistance to SPVD, and to determine the presence of Sweet potato virus G (SPVG), Sweet potato virus 2 (SPV2), and Sweet potato leaf curl virus (SPLCV), viruses that have not been reported infecting sweetpotato in Kenya. None of the samples reacted to antisera for either SPVG or SPV-2. SPLCV was detected infecting sweetpotato …

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Enzymatic Production And Biological Activities Of Cellobio-Oligosaccharides From Lignocellulose, Misook Kim Jan 2008

Enzymatic Production And Biological Activities Of Cellobio-Oligosaccharides From Lignocellulose, Misook Kim

LSU Doctoral Dissertations

Cellulose is the most abundant biopolymer in nature and is the major component of lignocellulosic biomass. It has potential to produce not only glucose but value¨Cadded products such as cellobiose and oligosaccharides. Typically, enzymatic hydrolysis of cellulose produces glucose and a small amount of cellobiose. Modification of cellulase solutions altered ratio of glucose to cellobiose produced. The addition of glucose oxidase, gluconolactone, or gluconic acid significantly increased the amount of cellobiose remaining at the end of cellulose hydrolysis. Addition of glucose oxidase resulted in cellobiose being 23.7% of the product sugars from pure cellulose and 14.1% from ligonocellulose (sugarcane bagasse). …

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Stochastic And Copula Models For Credit Derivatives, Chao Meng Jan 2008

Stochastic And Copula Models For Credit Derivatives, Chao Meng

LSU Doctoral Dissertations

We prove results relating to the exit time of a stochastic process from a region in N-dimensional space. We compute certain stochastic integrals involving the exit time. Taking a Gaussian copula model for the hitting time behavior, we prove several results on the sensitivity of quantities connected with the hitting times to parameters of the model, as well as the large-N behavior. We discuss the relationship of these results to certain credit derivative instruments. Relevant simulations are presented.

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A Century Of Land Use And Water Quality In Watersheds Of The Continental U.S., Whitney P. Broussard Iii Jan 2008

A Century Of Land Use And Water Quality In Watersheds Of The Continental U.S., Whitney P. Broussard Iii

LSU Doctoral Dissertations

Human endeavors, particularly the agricultural and industrial activities of the last half century, now produce more biologically available nitrogen (N) than all other natural sources combined. The increased N availability can have consequences for the health of aquatic biota on the local, regional, and global scales. One manifestation of this problem is the formation of coastal hypoxic zones where terrestrial N loading creates eutrophic conditions in coastal waters. This dissertation examines a century of changes in land use and water quality to quantify the relationships between agricultural land use practices and riverine N yields in the Mississippi River Basin and …

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The Perils And Empowerments Of Mountain Literacies: Reading Loss And Shifting Identities In Appalachian Memoirs And Novels, Erica Abrams Locklear Jan 2008

The Perils And Empowerments Of Mountain Literacies: Reading Loss And Shifting Identities In Appalachian Memoirs And Novels, Erica Abrams Locklear

LSU Doctoral Dissertations

This dissertation analyzes the literary portrayal of literacy events in memoirs and novels written by Appalachian women during the twentieth and twenty-first centuries. Drawing from contemporary literacy scholarship, my project engages several definitions of the term "literacy," including theories defining it as a technical skill, a social act, cultural knowledge, or a potent form of ideological power. In a region historically (and often inaccurately) stigmatized as illiterate, "literacy" is a loaded term, a concept doubly associated with cultural pride and with cultural loss. By applying literacy theories to Appalachian literature, I analyze the identity conflicts literacy attainment causes for several …

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The Diet Of Saltmarsh Consumers, Kari Ann Galvan Jan 2008

The Diet Of Saltmarsh Consumers, Kari Ann Galvan

LSU Doctoral Dissertations

Salt marshes are areas of high primary production that in turn support high secondary production. Macrophytes, phytoplankton and a variety of benthic algae all contribute to the high primary productivity. Each has the potential to contribute to the saltmarsh food web making it difficult to determine organic matter resources important to secondary production in salt marshes. Furthermore, our understanding of saltmarsh food webs is complicated by anthropogenic effects such as nutrient inputs and exploitation of key predators. I utilized a combination of natural abundance stable isotopes, isotope tracer additions, gut content analysis and manipulative experiments to determine the diets of …

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The Synthesis Of Water Soluble N-Acyl Chitosan Derivatives For Characterization As Antibacterial Agents, Lakia Monique Champagne Jan 2008

The Synthesis Of Water Soluble N-Acyl Chitosan Derivatives For Characterization As Antibacterial Agents, Lakia Monique Champagne

LSU Doctoral Dissertations

Currently, natural polysaccharides are being utilized increasingly in the markets because they exhibit biodegradability, biocompatibility, versatility, and are found abundant in nature. The diversity of natural polysaccharides provides the chemist with a broad spectrum of raw materials that can be used in many biological applications. Chitosan is a natural polysaccharide that possesses excellent biological properties. It has been recognized for its antibacterial activity, in that it is destructive towards the bacterium Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The antibacterial property of chitosan can be enhanced by changing the hydrophobic/hydrophilic nature of the polysaccharide backbone. This research entails …

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The Use Endocrine Markers To Predict And Monitor Performance In Strengh [Sic] And Power Activities, Jason B. Winchester Jan 2008

The Use Endocrine Markers To Predict And Monitor Performance In Strengh [Sic] And Power Activities, Jason B. Winchester

LSU Doctoral Dissertations

Hormones are typically considered to be chemical messengers, which are designed to be released from specific cells where they are carried to their target tissues for binding to receptors. It is this binding of a hormone molecule to its specific receptor which allows for an action to occur (Hadley and Levine 2006). Testosterone is the predominant androgen in the majority of mammalian species and is largely responsible for regulation of reproduction and maintenance of sexual function. In addition, in adult mammals, T has multiple other roles including the growth of muscle and bone, hematopoesis, blood coagulation, development and regulation of …

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Cryopreservation Of Adipose Derived Adult Stem Cells And Multidimensional Cell Sheets, Sreedhar Thirumala Jan 2008

Cryopreservation Of Adipose Derived Adult Stem Cells And Multidimensional Cell Sheets, Sreedhar Thirumala

LSU Doctoral Dissertations

Human adipose tissue provides a uniquely abundant and accessible source of adult stem cells. In response to chemical, hormonal or structural stimuli, these human adipose-derived adult stem (ASCs) cells can differentiate along multiple lineage pathways, including adipocytes, chondrocytes, myocytes, neurons and osteoblasts. Successful cryopreservation of scientifically and commercially important ASCs would revolutionize the tissue engineering and regenerative medicine industry. In this research, we have investigated the water transport phenomenon during freezing of several passages of adipose derived adult stem cells and generated the membrane permeability parameters in the presence and absence of cryoprotective agents. These measured permeability parameters were then …

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Iron And Zinc Physiology In Sweetpotato, Mary Catherine Singleton Jan 2008

Iron And Zinc Physiology In Sweetpotato, Mary Catherine Singleton

LSU Master's Theses

Sweetpotato [Ipomoea batatas (L.) Lam.] is an important provider of nutrition in developing countries. High productivity in the form of starch and beta carotene richness underlies its potential. A sweetpotato with adequate levels of iron and zinc would greatly aid efforts to reduce dietary deficiencies of iron and zinc. The objective of this work is to document the physiological accumulation of iron and zinc in sweetpotato during development and the mechanisms responsible for iron uptake. Six varieties (‘IPS 163, ‘Beauregard’,‘Koto-puki’, ‘Pung-mi’, ‘Duanyanghon’, and ‘Xushu 18’) were compared to understand iron and zinc accumulation during development. Results showed that micronutrient content …

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An Experimental Study On The Formation Of Polycyclic Aromatic Hydrocarbons During The Pyrolysis And Oxidation Of Catechol[Ortho-Dihydroxybenzene]-A Model Compound Representative Of Structural Units In Coal, Wood, And Biomass, Shiju Thomas Jan 2008

An Experimental Study On The Formation Of Polycyclic Aromatic Hydrocarbons During The Pyrolysis And Oxidation Of Catechol[Ortho-Dihydroxybenzene]-A Model Compound Representative Of Structural Units In Coal, Wood, And Biomass, Shiju Thomas

LSU Doctoral Dissertations

Polycyclic aromatic hydrocarbons (PAH) formed during the pyrolysis and combustion of solid fuels like coal, wood, and biomass are widespread environmental pollutants. Since some PAH are known to exhibit carcinogenic and mutagenic activity, understanding the chemical reactions responsible for PAH formation is of utmost importance. To better understand the reactions leading to the formation of PAH from complex solid fuels, pyrolysis and oxidation experiments have been performed in an isothermal laminar-flow reactor, using the model fuel catechol (ortho-dihydroxybenzene), a phenol-type compound representative of structural entities in coal, wood, and biomass. Catechol pyrolysis experiments have also been performed in the presence …

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The Effects Of Cross-Age Mentoring In An Online Collaborative Environment, Gail Lorraine Johnson Jan 2008

The Effects Of Cross-Age Mentoring In An Online Collaborative Environment, Gail Lorraine Johnson

LSU Doctoral Dissertations

This mixed method research was designed to examine the effects of cross-age mentoring in an inter-institutional online learning community. The research questions focused on the impact of mentoring on high school students’ confidence in their information seeking skills, perceptions of their information seeking standards, and the application of these standards to an information seeking task. Also of interest was the dialogic interaction between the students at the two sites, the impact of the facilitator on the process, and the university students’ perceptions about their experience. The participants included 26 students (mentees) enrolled in an American history class at a rural …

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Academic Impropriety: Violation Of Normative Teaching Behaviors As Identified By Nursing Educators, Melanie Hilburn Green Jan 2008

Academic Impropriety: Violation Of Normative Teaching Behaviors As Identified By Nursing Educators, Melanie Hilburn Green

LSU Doctoral Dissertations

With public criticism of American higher education on the rise, it is prudent for those in the academy to reflect upon their responsibilities to their students. Of particular salience is an examination of what constitutes misconduct within the faculty role. This dissertation reports the results of a study designed to identify what nursing educators believe to be the violation of normative teaching behaviors. A sequential explanatory mixed methods design was utilized to develop an understanding of the actions that constitute academic impropriety. The College Teaching Behaviors Inventory, a survey instrument designed by Braxton and Bayer (1999), was distributed to deans …

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Genetic Analysis Of The Boundary Element Associated Factors-Beaf32a And Beaf-32b, Swarnava Roy Jan 2008

Genetic Analysis Of The Boundary Element Associated Factors-Beaf32a And Beaf-32b, Swarnava Roy

LSU Doctoral Dissertations

Insulators are DNA elements that have been shown to restrict the communication between enhancers and promoters in transgenic assays. In my PhD work I have attempted to highlight the function and importance of insulators by using the Boundary Element Associated Factors- BEAF -32A and BEAF-32B as model insulator binding proteins. We generated a null BEAFAB-KO allele and BEAFA-KO allele by using homologous recombination method. BEAF-32B was found to be sufficient to obtain viable flies. Our results show that BEAF is required for both oogenesis and development. Position independent expression and enhancer-blocking assays showed that BEAF confers insulator function to scs’ …

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Bile Salts As Olfactory And Gustatory Stimuli In The Channel Catfish, Shane Howell Rolen Jan 2008

Bile Salts As Olfactory And Gustatory Stimuli In The Channel Catfish, Shane Howell Rolen

LSU Doctoral Dissertations

A chemotopic map of biologically relevant odorants (that include amino acids, bile salts and nucleotides) exists in the olfactory bulb (OB) and forebrain (FB) of channel catfish, Ictalurus punctatus (Chapter one). Neurons processing bile salt odorant information lie medially within these bilaterally symmetric structures; however, information as to how single neurons discriminate and process this odorant information is lacking. Chapters two and three of the dissertation identify the range of odorant bile salt molecules that excite these neurons [i.e. the excitatory molecular receptive range (EMRR)] within the bile salt chemotopic zones of the OB and FB. The results of the …

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Trophic Control Of Saltmarsh Invertebrates, David Samuel Johnson Jan 2008

Trophic Control Of Saltmarsh Invertebrates, David Samuel Johnson

LSU Doctoral Dissertations

Top-down (consumer) versus bottom-up (resource) control of food webs has long interested ecologists. Here, I take advantage of a full-factorial design of ecosystem-wide manipulations of nutrient additions (loading rates 10x above background) and the significant reduction (~60%) of a key predator, the killifish Fundulus heteroclitus, in the tidal creeks of the Plum Island Estuary, Massachusetts. Prior to manipulations, annelids numerically constituted 97% of the infaunal community and the largest scale (creeks) accounted for little spatial variability in annelid populations and diversities. Tidal creeks were similar based on diversity indices, abundance, and community patterns, suggesting the tidal creeks are appropriate replicates/experimental …

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Medical Geography In Public Health And Tropical Medicine: Case Studies From Brazil, William Brennan Arden Jan 2008

Medical Geography In Public Health And Tropical Medicine: Case Studies From Brazil, William Brennan Arden

LSU Doctoral Dissertations

Within the last few decades, the multitude of infrastructural and environmental changes associated with population growth, human migration, and economic development have catalyzed the emergence and re-emergence of many infectious diseases worldwide. The morbidity and mortality associated with these diseases have in turn led to an increased and renewed impetus to gain a better understanding of the etiology, epidemiology, prevention, and control of these diseases in order to achieve better health and well-being, especially for underprivileged populations. Two traditionally separate fields, medical geography and tropical medicine, have recently seen complex and radical paradigm shifts in response to this global situation: …

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The Effect Of Contamination, Sediment Source And Salinity On The Uptake, Distribution, And Excretion Of Metals By Spartina Alterniflora, Sarahfaye Mahon Jan 2008

The Effect Of Contamination, Sediment Source And Salinity On The Uptake, Distribution, And Excretion Of Metals By Spartina Alterniflora, Sarahfaye Mahon

LSU Doctoral Dissertations

Spartina alterniflora, the dominant vegetation in many salt marshes, has the potential to remobilize metals (Cd, Cr, Cu, Ni, Pb, Zn) from sediment to the local salt marsh environment. My research determined the influence of sediment metal concentration, sediment type and salinity on the uptake, distribution and accumulation of metals by S. alterniflora tissues and excreted salts. Spartina alterniflora was cultivated at a constant salinity in natural and dredge sediments with three levels of metal additions (control, low, and high). The distribution and concentration of metals in S. alterniflora was influenced by both metal treatments and sediment type; however, the …

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The Influence Of Peripheral Neuropathy On Walking Kinematics And Physical Function, Bradley Manor Jan 2008

The Influence Of Peripheral Neuropathy On Walking Kinematics And Physical Function, Bradley Manor

LSU Doctoral Dissertations

The 108th Congress (2005) has reported that 20 million U.S. citizens suffer from Peripheral Neuropathy (PN). Characterized by sensory nerve deterioration, PN reduces somatosensation (Padua et al., 2005) and increases the risk of fall-related injury (Richardson et al., 1992). The purpose of this dissertation was to provide insight into 1) the effects of acute loss of foot sole sensation on locomotor system health, 2) the effects of PN on locomotor system health, and 3) the underlying impairments associated with reduced physical function within the older adult and PN populations. Locomotor system health was assessed by the magnitude of stride-to-stride variability …

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Space-Time Multiresolution Approach To Atomistic Visualization, Dipesh Bhattarai Jan 2008

Space-Time Multiresolution Approach To Atomistic Visualization, Dipesh Bhattarai

LSU Doctoral Dissertations

Time-varying three-dimensional positional atomistic data are rich in spatial and temporal information. The problem is to understand them. This work offers multiple approaches that enable such understanding. An interactive atomistic visualization system is developed integrating complex analyses with visualization to present the data on space-time multiresolution basis facilitating the information extraction and generate understanding. This work also shows the usefulness of such an integrated approach. The information obtained from the analyses represents the system at multiple length and time scales. Radial distribution function (RDF) provides a complete average spatial map of the distribution of the atoms in the system which …

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Ecological Genomics Of High Altitude Adaptation In Rufous-Collared Sparrows (Zonotrichia Capensis), Zachary A. Cheviron Jan 2008

Ecological Genomics Of High Altitude Adaptation In Rufous-Collared Sparrows (Zonotrichia Capensis), Zachary A. Cheviron

LSU Doctoral Dissertations

Adaptation is among the most prominent subjects in evolutionary biology. Despite its ubiquity in nature, many details of how adaptation occurs in natural populations remain poorly understood. Of particular interest are the genes and biochemical pathways that underlie adaptive phenotypes and how plasticity in these systems contributes to adaptive evolution. In this dissertation, I address these questions by investigating the molecular genetic basis of high-altitude adaptation in the Rufous-collared Sparrow (Zonotrichia capensis), a species with a broad altitudinal distribution in the Andes. First, I examined the role that variable selection pressures along elevational gradients play in the population genetic structure …

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Resistance To Bacillus Thuringiensis In Sugarcane Borer, Diatraea Saccharalis (F.), Xiaoyi Wu Jan 2008

Resistance To Bacillus Thuringiensis In Sugarcane Borer, Diatraea Saccharalis (F.), Xiaoyi Wu

LSU Doctoral Dissertations

The sugarcane borer, Diatraea saccharalis (F.), is a dominant corn stack boring pest and a major target of Bacillus thuringiensis (Bt)-corn in many areas of the mid-southern region of the United States. A Cry1Ab-resistant strain of D. saccharalis, capable of survival on commercial Bt corn plants, was established using an F2 screening procedure. Larval survival of Cry1Ab-resistant, -susceptible, and -heterozygous genotypes was evaluated on five non-Bt and seven Bt field corn hybrids at two plant stages. During the vegetative stages, all seven Bt corn hybrids were highly efficacious against the three genotypes, while 8-18% of the heterozygous genotype survived on …

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The Principal As Technology Leader: The Skills E-Learners Consider Essential To The Creation Of A Technology-Rich School Community, Tammy Sue Seneca Jan 2008

The Principal As Technology Leader: The Skills E-Learners Consider Essential To The Creation Of A Technology-Rich School Community, Tammy Sue Seneca

LSU Doctoral Dissertations

This study examined the skills that e-learners considered essential to the creation of a technology-rich school community. The focus was upon the skills that acting district and school administrators deemed essential to becoming an effective e-leader. The quantitative investigation associated with this study consisted of a researcher created survey based upon the International Society of Technology Educators (ISTE) National Educational Technology Standards for Administrators (NETS-A). The intent of this survey was to obtain a list of skills that the participants felt were necessary for administrators to obtain in order to be effective leaders. These skills are categorized into both theory-based …

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Detection Of Rare Tp53 And Kristen-Ras Mutational Frequencies In Human Sperm, Derek N. Cole Jan 2008

Detection Of Rare Tp53 And Kristen-Ras Mutational Frequencies In Human Sperm, Derek N. Cole

LSU Doctoral Dissertations

There is mounting evidence of impacts of single base substitutions in both somatic and inherited genetic diseases. However, the occurrence of single base mutations in the germline and gametes has previously only been by conjecture and assumption. There is a need for understanding the risk of offspring inheriting small intragenic mutations, the frequencies at which these mutations are present in germ cells, and the impact that these inherited mutations may have son the predisposition to somatic disease during one’s lifetime. The present study attempts to establish baselines of mutational frequencies in two well characterized genes in human tissues, and demonstrate …

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Phylogeogaphy Of Nothoprocta Tinamous And The The Phylogeny Of The Tinamidae, Thomas Valqui Jan 2008

Phylogeogaphy Of Nothoprocta Tinamous And The The Phylogeny Of The Tinamidae, Thomas Valqui

LSU Doctoral Dissertations

Understanding how diversity is attained and maintained is one of the central questions in biology. In the Neotropics most attention has centered on the Amazonian lowlands, despite the recognized importance of the role of the Andes in South American diversity. In this dissertation, I address the question by using Nothoprocta tinamous as a model case for examining diversification in the Andes. As a group, they are a manageable size, they exhibit near-restriction to the Andes, they show multi-species parapatric distributions, and they have presumed limited dispersal ability. These are all useful attributes for a system to study speciation and diversification. …

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A Novel Modulatory Role For Nitric Oxide In Retinal Amacrine Cells, Emily Ann Mcmains Jan 2008

A Novel Modulatory Role For Nitric Oxide In Retinal Amacrine Cells, Emily Ann Mcmains

LSU Doctoral Dissertations

Nitric oxide is a gaseous signaling molecule that is produced by subsets of each cell type in the vertebrate retina. Though there is evidence that nitric oxide (NO) can affect multiple cellular processes in the retina, much remains unknown, especially with respect to its function in the inner retina. We have used a simplified system of cultured amacrine cells (interneurons that signal in the inner retina) to explore the role of nitric oxide in amacrine cell signaling. We find that physiological concentrations (100’s of nM – low μM) of nitric oxide (NO) transiently invert the sign of voltage responses mediated …

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Concentration Of Phosphorylated Proteins Using Modified Pmma Microanalytical Devices, Jowell Guerra Bolivar Jan 2008

Concentration Of Phosphorylated Proteins Using Modified Pmma Microanalytical Devices, Jowell Guerra Bolivar

LSU Doctoral Dissertations

This work describes the application of PMMA-based microanalytical devices for the affinity-type preconcentration of posttranslational modified proteins (PTMs). The choice of poly(methyl methacrylate), PMMA, is based on its biocompatibility, its functional methyl ester group for potential modification, and its extensive applications to create biological microelectromechanical systems (BioMEMS). Developing methodologies for preconcentration of PTMs is important for cancer diagnosis due to PTMs’ influence in the regulatory mechanism underlying the early stage of apoptosis or regulated cell death. Towards this goal, nitroavidin which can reversibly binds to biotin (and biotinylated proteins), was prepared using reported procedure and was characterized using several techniques …

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