Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Louisiana State University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 11431 - 11460 of 13623

Full-Text Articles in Entire DC Network

Extraction And Analysis Of Triazines In Fish Tissues Following A Toxic Exposure: Environmental Factors Affecting Atrazine Toxicity In Fish., Patricia Simmons Gaunt Jan 1996

Extraction And Analysis Of Triazines In Fish Tissues Following A Toxic Exposure: Environmental Factors Affecting Atrazine Toxicity In Fish., Patricia Simmons Gaunt

LSU Historical Dissertations and Theses

Rapid, generic, and environmentally friendly methods for extraction and detection of the pesticides atrazine, cyanazine, metribuzin, and simazine were developed for use in monitoring the cause of pesticide related or suspect fish kills. Further, environmental hypoxia and elevated temperature were studied as possible contributors to the toxicity of atrazine in channel catfish (Ictalurus punctatus) and as synergistic factors to be considered in investigating fish kill events. Incurred residues from the exposure of catfish to atrazine alone or hypoxia or elevated temperature and atrazine were also analyzed. A commercial enzyme-linked immunoassay (ELISA) was utilized as a screening method for the presence …

Go to article

Characterization Of Variant Equine Infectious Anemia Virus Long Terminal Repeat Sequences., Charles Richard Madden Jan 1996

Characterization Of Variant Equine Infectious Anemia Virus Long Terminal Repeat Sequences., Charles Richard Madden

LSU Historical Dissertations and Theses

Equine infectious anemia virus (EIAV) is the causative agent of a persistent disease in horses. The long terminal repeat (LTR) region of EIAV contains the enhancer and promoter elements necessary for transcription of the proviral genome. The LTR is also prone to a high degree of sequence variability between different virus isolates. Sequence alignments of LTR variants from both tissue culture-adapted strains of the virus as well as sequential horse isolates showed a high degree of sequence variability between variants. Sequence variability was further localized to a hypervariable region approximately 60 bp upstream of the TATA box. This region contained …

Go to article

The Effects Of Timber Management Activities On Understory Plant Succession In Young Loblolly Pine (Pinus Taeda) Plantations., Donald Paul Reed Jan 1996

The Effects Of Timber Management Activities On Understory Plant Succession In Young Loblolly Pine (Pinus Taeda) Plantations., Donald Paul Reed

LSU Historical Dissertations and Theses

An understory vegetative succession study was conducted on the LSU Lee Memorial Forest near Bogalusa, Louisiana. Research blocks were established within fifteen-year-old overstocked loblolly pine (Pinus taeda) stands, in specific areas classified as with or without a history of prescribed burning for the current timber rotation. Silvicultural treatments involved precommercially thinning randomly selected blocks to various stand densities, along with the establishment of unthinned control areas. Growth rates of residual trees were determined from tree diameter measurements, on all timbered plots. Burn-history areas received a further treatment, involving the mechanical destruction of all timber on specified areas, followed by site-preparation …

Go to article

Dinitropyrenes: Nitroreduction Processes And Evaluation Of Indices Of Exposure., Matthew Jerome Krautmann Jan 1996

Dinitropyrenes: Nitroreduction Processes And Evaluation Of Indices Of Exposure., Matthew Jerome Krautmann

LSU Historical Dissertations and Theses

Investigations were conducted to identify biomarkers of exposure to dinitropyrenes (DNPs), which are mutagenic and carcinogenic residues of incomplete combustion. One possible biomarker, a DNP-protoporphyrin IX adduct, was not found in analytically useful quantities in liver tissue or in bile. Clastogenicity, a biomarker of effect, also was found to be absent in marrow cells following subchronic exposure of rats to DNPs by gavage. Solubility studies, used as a basis for dosing guidelines, revealed that DNPs are relatively insoluble in both aqueous and lipid tissue compartments. Calculated log P values indicated that the reduced metabolites of DNPs probably are more soluble …

Go to article

Characterization Of Physiological Changes In Roots Grown In Spaceflight Conditions: A Comparison Of Nutrient Delivery Technologies., David Marshall Porterfield Jan 1996

Characterization Of Physiological Changes In Roots Grown In Spaceflight Conditions: A Comparison Of Nutrient Delivery Technologies., David Marshall Porterfield

LSU Historical Dissertations and Theses

The best strategy for providing food and maintaining the environment on long-duration space missions is a bioregenerative life support system based on the growth of higher plants. Before such a system can be implemented, a better understanding of plant growth in space will have to be achieved. Little is known about the role of gravity-dependent physical processes in normal physiological function. A series of ground-based and spaceflight experiments was conducted to examine root oxygen availability in microgravity nutrient delivery systems. In spaceflight experiments Arabidopsis thaliana (L.) Heynh. plants were analyzed for changes in root medium redox potential and root alcohol …

Go to article

Interrelationships Between Meloidogyne Incognita And Rotylenchulus Reniformis On Soybean., Salliana Ryan Stetina Jan 1996

Interrelationships Between Meloidogyne Incognita And Rotylenchulus Reniformis On Soybean., Salliana Ryan Stetina

LSU Historical Dissertations and Theses

The replacement series approach was used to evaluate competition between Meloidogyne incognita (Mi) and Rotylenchulus reniformis (Rr). In greenhouse tests, soil in pots containing 'Davis' soybean was not infested or infested with 1,000 vermiform nematodes in the following Mi:Rr ratios: 100:0, 75:25, 5:50, 25:75, and 0:100. After 86 days, relative nematode yields (RNYs) (number of each species in mixed culture divided by number in nonmixed culture) were calculated based on soil populations. Calculated values were plotted and the resulting line compared with a reference line representing equal inter- and intraspecific competition. RNYs for Mi were higher than predicted where Mi …

Go to article

Paleoindicators Of Changing Water Conditions In Louisiana Estuaries., Michael Lewis Parsons Jan 1996

Paleoindicators Of Changing Water Conditions In Louisiana Estuaries., Michael Lewis Parsons

LSU Historical Dissertations and Theses

Sediment cores were collected to study the development of eutrophication and hydrological changes in coastal Louisiana. The cores were taken at marsh sites hypothesized to be influenced primarily by riverine inputs (Fourleague Bay-FLB), localized activities (Terrebonne Bay-TSMP), and both riverine and localized processes (Airplane Lake-APL). The sediment cores represented time frames ranging from 330 years (APL) to 70 years (TSMP) BP according to core dating results. Sediment core samples were analyzed for diatoms, other microfossils, pigments, biogenic silica, and sediment characteristics. Additionally, land use records were utilized as a proxy of anthropogenic activities, and to aid in the interpretation of …

Go to article

Gumbo Yearbook, Class Of 1996, Louisiana State University And Agricultural And Mechanical College Jan 1996

Gumbo Yearbook, Class Of 1996, Louisiana State University And Agricultural And Mechanical College

Gumbo Yearbook

The Gumbo yearbook chronicles the entire academic year at LSU. In words and especially photos, the Gumbo shows the people, places, and events that make each year unique. In addition to formal portraits of schools and departments, the book contains hundreds of snapshots of students with their friends and dozens of pages showcasing organizations.

Go to article

Reconstructing Educational Experience: A Postmodern Perspective., Jeanne Edwards Robertson Jan 1996

Reconstructing Educational Experience: A Postmodern Perspective., Jeanne Edwards Robertson

LSU Historical Dissertations and Theses

Education in America today is dominated by the either/or thinking of modernism. This mode of thought is connected to both the concepts and methods of modern, mechanistic, Newtonian science. However, the attendant reductionistic methodology has been elevated beyond its realm of efficacy to the level of a world view, a metaphysical level. This is demonstrated by the omnipresence of the machine metaphor in all areas of human endeavor. The machine is the root metaphor of modernism. John Dewey speaks of a "new order of conceptions" necessary for significant change. These new order concepts are manifest in the new or postmodern …

Go to article

Impact Of Insecticides On Predators Of The Soybean Looper, Pseudoplusia Includens (Walker)., Michael Lynn Boyd Jan 1996

Impact Of Insecticides On Predators Of The Soybean Looper, Pseudoplusia Includens (Walker)., Michael Lynn Boyd

LSU Historical Dissertations and Theses

Insecticide toxicity to hemipteran predators (i.e. Geocoris punctipes (Say), Nabis capsiformis Germar, Nabis roseipennis Reuter, and Podisus maculiventris (Say)) was evaluated using three different routes of insecticide exposure (direct contact, indirect insecticide toxicity through consumption of treated prey, and residue uptake). Pirate 3SC$\sp\circler$ (chlorfenapyr) had direct contact toxicity equal to Ambush 2E$\sp\circler$ (permethrin) and Methyl Parathion 4E$\sp\circler$ to most hemipteran predators tested. Exposure to foliage treated with Proclaim 0.16E$\sp\circler$ (emamectin benzoate) usually resulted in lower mortality as compared to Pirate. Condor OF 100F$\sp\circler$ (Bacillus thuringiensis) had the lowest contact toxicity to hemipteran predators of all insecticides tested. Pirate at 0.224 …

Go to article

Cloning, Sequencing And Regulation Of The Rhodobacter Capsulatusheme Gene., Georgia Ineichen Jan 1996

Cloning, Sequencing And Regulation Of The Rhodobacter Capsulatusheme Gene., Georgia Ineichen

LSU Historical Dissertations and Theses

In Rhodobacter capsulatus, a purple nonsulfur bacterium, the tetrapyrrole pathway yields four end products: siroheme, vitamin B12, heme and bacteriochlorophyll. Growth of R. capsulatus under low oxygen tension increases carbon flow through the tetrapyrrole pathway up to 100 fold. The mechanism(s) for this regulation is currently unknown. One regulatory mechanism could be transcriptional control of one or more of the genes in the common portion of the tetrapyrrole pathway. The fifth gene in the pathway, hemE, has been cloned by complementation of an Escherichia coli hemE::miniTn10 mutant. Sequence data of hemE revealed the presence of an upstream palindrome that is …

Go to article

Importance Of A Siderophore In The Pathogenesis And Virulence Of Photobacterium Damsela Subsp. Piscicida In Hybrid Striped Bass (Morone Saxatili X Morone Chrysops)., John Phillip Hawke Jan 1996

Importance Of A Siderophore In The Pathogenesis And Virulence Of Photobacterium Damsela Subsp. Piscicida In Hybrid Striped Bass (Morone Saxatili X Morone Chrysops)., John Phillip Hawke

LSU Historical Dissertations and Theses

Photobacterium damsela subsp. piscicida, formerly Pasteurella piscicida, is an important new pathogen of hybrid striped bass cultured in brackish water on Louisiana mariculture farms. Louisiana isolates compared with strains of P. damsela subsp. piscicida from Greece, Japan, Israel and Chesapeake Bay, USA and were found to be identical in biochemical phenotype and enzymic activity. Small plasmids of 8 and 5 kb were unique to Louisiana strains. Sequential daily bacteriology and histopathology on hybrid striped bass experimentally infected by immersion revealed that following high doses (13,000 CFU/ml) the gills and spleen are colonized first as early as 24 hours PI, followed …

Go to article

Amorphization And Fracture In Silicon Selenium(2) Nanowires: Molecular-Dynamics Simulations On Parallel Computer Architectures., Wei Li Jan 1996

Amorphization And Fracture In Silicon Selenium(2) Nanowires: Molecular-Dynamics Simulations On Parallel Computer Architectures., Wei Li

LSU Historical Dissertations and Theses

The primary goal of this dissertation is to investigate the structural and mechanical properties and dynamical fracture in SiSe$\sb2$ nanowires using the molecular-dynamics (MD) simulation technique. The present work is the first study of SiSe$\sb2$ nanowires. Large-scale simulations reported in this thesis are carried out with parallel multiresolution schemes for the long-range Coulomb and the three-body covalent potentials. The multiresolution scheme reduces the computational complexity from O(N$\sp2$) to O(N). Using an effective interatomic potential containing both 2- and 3-body interactions, MD simulations are performed for SiSe$\sb2$ nanowires composed of finite (1-64) number of chains. Under small uniaxial strain, the nanowires …

Go to article

Experimental Lymphatic Filariasis In Gerbils (Meriones Unguiculatus): Molecular Cloning And Expression Of Gerbil Cytokines And Measurement Of Cytokine Gene Expression During A Primary Infection Of Brugia Pahangi., Zhiming Mai Jan 1996

Experimental Lymphatic Filariasis In Gerbils (Meriones Unguiculatus): Molecular Cloning And Expression Of Gerbil Cytokines And Measurement Of Cytokine Gene Expression During A Primary Infection Of Brugia Pahangi., Zhiming Mai

LSU Historical Dissertations and Theses

Cytokines play an important role in regulation of T cell responses. Two T helper cell subsets have been identified in some species and are defined by their cytokine secretion profiles. Th1 cells produce IL-2 and IFN-$\gamma,$ whereas Th2 cells express IL-4, IL-5, and IL-10. Precursor T cells that express a mixture of these cytokines are considered Th0 cells. It is hypothesized that primary infections of Brugia pahangi in gerbils induce an initial Th0 or Th1 like response which with time becomes a Th2 like response. To test this dynamic parasitism induced shift in cytokine profile, it is necessary to measure …

Go to article

Inflammatory Responses Of The Jird To Brugia Pahangi: Parasite Stage Specificity And Role Of The Macrophage., Carmen Nasarre Jan 1996

Inflammatory Responses Of The Jird To Brugia Pahangi: Parasite Stage Specificity And Role Of The Macrophage., Carmen Nasarre

LSU Historical Dissertations and Theses

The host systemic and peritoneal inflammatory responses against different stages of Brugia pahangi were compared in intraperitoneally infected-jirds. Systemic inflammatory responses were assessed by measuring the pulmonary granulomatous response to B. pahangi antigen-coated beads (PGRN). Peritoneal inflammation was characterized by enumeration of different cell types in peritoneal exudates following infection. Further, the toxoplasmacidal activity and TNF-$\alpha$-like production of peritoneal macrophages were also characterized. Infection with L3, L4, male worms, female worms, microfilariae (MF) or dead adult worms induced a rapid PGRN. This response decreased to levels of controls in jirds inoculated with living parasites at the chronic time period, indicating …

Go to article

Effect Of Diet On Respiratory Fuel Mixture, Insulin Sensitivity, And Autonomic Nervous System Function., Heli J. Roy Jan 1996

Effect Of Diet On Respiratory Fuel Mixture, Insulin Sensitivity, And Autonomic Nervous System Function., Heli J. Roy

LSU Historical Dissertations and Theses

Introduction. A high amount of dietary fat has been shown to have a negative effect on metabolism, causing insulin resistance, weight gain, and other metabolic alterations. Several studies have found a direct link between lack of activity and obesity. Purpose. The purpose of this study was to see if a diet had an effects on insulin sensitivity, autonomic nervous system function, and substrate utilization as predicted by Flatt, in healthy young men. Subjects. The subjects studied were 6 nonathletes (NA), 6 aerobically trained (AT), and 5 weight trained (WT) men. Their body mass index (BMI) was 22.1 $\pm$ 2.92 kg/m$\sp2$ …

Go to article

Modeling Physical And Chemical Nonequilibrium Transport Of Herbicide In Soils From Different Tillage Systems., Shikui Xue Jan 1996

Modeling Physical And Chemical Nonequilibrium Transport Of Herbicide In Soils From Different Tillage Systems., Shikui Xue

LSU Historical Dissertations and Theses

The physical and chemical nonequilibrium transport of alachlor were studied in a surface Gigger soil from different tillages through tracer studies, and batch and miscible displacement experiments. Batch experiments indicated initially fast reaction followed by slow adsorption. Adsorption and desorption results indicated time dependent hysteretic behavior and was best described by a multireaction model incorporating nonlinear equilibrium reaction, a reversible kinetic mechanism, and a consecutive irreversible mechanism. The model predicted alachlor hysteresis and adsorption-desorption kinetics satisfactorily based on parameters obtained from adsorption experiments. Tracer (Eosin Y and Blue FCF dyes) studies showed non-uniformly stained areas in undisturbed soil cores (6.4 …

Go to article

Work Motivation And Perceived Organizational Effectiveness In Middle Schools., Cynthia Young Wren Jan 1996

Work Motivation And Perceived Organizational Effectiveness In Middle Schools., Cynthia Young Wren

LSU Historical Dissertations and Theses

The primary purpose of this study was to determine the linkage between work motivation derived from the expectancy theory and perceived organizational effectiveness derived from the Parsonian framework. School characteristics of community type, school size, and school socioeconomic status were used as predictor variables in the study. A secondary purpose was to examine these linkages in middle schools and to examine changes over time. Mixed methodologies, including quantitative and qualitative research techniques, were employed. The data were analyzed using the school and the individual teacher as units of analyses. To test the hypotheses, a multiple regression procedure was employed. The …

Go to article

Robust Sensor Fusion Algorithms: Calibration And Cost Minimization., Richard Ree Brooks Jan 1996

Robust Sensor Fusion Algorithms: Calibration And Cost Minimization., Richard Ree Brooks

LSU Historical Dissertations and Theses

A system reacting to its environment requires sensor input to model the environment. Unfortunately, sensors are electromechanical devices subject to physical limitations. It is challenging for a system to robustly evaluate sensor data which is of questionable accuracy and dependability. Sensor fusion addresses this problem by taking inputs from several sensors and merging the individual sensor readings into a single logical reading. The use of heterogeneous physical sensors allows a logical sensor to be less sensitive to the limitations of any single sensor technology, and the use of multiple identical sensors allows the system to tolerate failures of some of …

Go to article

The Use Of Communication Facilitators With Severely Brain Injured Non-Responsive Adults., Alisa Judith Mendoza Jan 1996

The Use Of Communication Facilitators With Severely Brain Injured Non-Responsive Adults., Alisa Judith Mendoza

LSU Historical Dissertations and Theses

Slow-to-Recover (STR) individuals are a subset of the neurologically impaired population who remain non-responsive for extended periods of time before beginning to demonstrate improvement in cognitive, communicative, or motor function. This investigation focuses on the development and implementation of a facilitator-based intervention program carried out with an STR brain injured adult residing in a long-term care facility. The model involved: (1) sensory stimulation techniques to increase responses to external stimuli, (2) augmentative techniques which enabled the subject to control his immediate environment and, (3) training of qualified residents within the facility to act as communication facilitators. Ethnographic procedures were employed …

Go to article

The Association Between Chronic Aerobic Activity And Heart Rate Variability In Patients With Coronary Artery Disease., Robert Howard Wood Jan 1996

The Association Between Chronic Aerobic Activity And Heart Rate Variability In Patients With Coronary Artery Disease., Robert Howard Wood

LSU Historical Dissertations and Theses

Poor heart rate variability (HRV) among patients with coronary artery disease (CAD) is predictive of future incidence of sudden arrhythmic and all-cause death. Furthermore, mental stress appears to further depress HRV in these patients. Chronic aerobic activity level appears to be positively related to HRV among the general population; however, the extent to which this relationship exists among patients with CAD is not clear. Therefore, this study investigated the association between level of chronic aerobic activity and HRV among CAD patients during conditions of paced respiratory control and during the Stroop Color-Word Conflict Test (CWCT). CAD patients were assigned to …

Go to article

Microsatellite-Based Paternity Analysis In Hexaploid Sweetpotato (Ipomoea Batatas (L.) Lam.)., Mario Ignacio Buteler Jan 1996

Microsatellite-Based Paternity Analysis In Hexaploid Sweetpotato (Ipomoea Batatas (L.) Lam.)., Mario Ignacio Buteler

LSU Historical Dissertations and Theses

The use of genetic markers for paternity identification was investigated in hexaploid sweetpotato. Traditional sweetpotato breeding relies on the open pollination of numerous parents and the visual selection of progeny. Previous empirical and theoretical evidence shows this type of breeding system is extremely inefficient. Typically, only a few of these maternal parents routinely produce superior progeny. A similar scenario exists for the paternal parent. Identifying specific parental combinations which produce superior progeny would improve breeding efficiency, hence the need to identify paternity in superior progeny. A computer simulation study established the minimum number of alleles and loci required for paternity …

Go to article

Movements, Habitat Use, And Survival Of Female Northern Pintails In Southwestern Louisiana., Robert Ripley Cox Jr Jan 1996

Movements, Habitat Use, And Survival Of Female Northern Pintails In Southwestern Louisiana., Robert Ripley Cox Jr

LSU Historical Dissertations and Theses

I developed portable platforms for setting rocket nets in open-water habitats, and used them to capture 1116 waterfowl of 7 species during winters 1991-92 and 1992-93 in southwestern Louisiana. Distance and duration of evening flights of female northern pintails (Anas acuta; hereafter pintails) from Lacassine National Wildlife Refuge increased with date within wintering period, and generally were greater than previously reported estimates for wintering waterfowl. I found that diurnal use of refuges by females increased during hunting seasons, contradicting Tamisier's hypothesis that use of refuges by pintails in southwestern Louisiana is not influenced by hunting. Female pintails extensively used privately …

Go to article

Cytogenetic And Molecular Analysis Of The Channel Catfish (Ictalurus Punctatus) Genome., Quiyang Zhang Jan 1996

Cytogenetic And Molecular Analysis Of The Channel Catfish (Ictalurus Punctatus) Genome., Quiyang Zhang

LSU Historical Dissertations and Theses

This research presents studies on cytogenetics and molecular genetics of channel catfish (Ictalurus punctatus), the most important fish species cultured in the United States. The goals of this project were to analyze the genome of the channel catfish and to develop a direct method of mapping single-locus genes. A series of techniques were developed to facilitate these studies, including culture of fibroblast cells, preparation of chromosomes from catfish of different ages, staining for nucleolus organizer regions (NOR) and heterochromatin (C-banding), restriction enzyme banding, replication R-banding, simultaneous detection of sister-chromatid exchange (SCE) and C-banding, fluorescent in-situ hybridization (FISH) and indirect and …

Go to article

Molecular Systematics Of Red Algae., Jeffrey Craig Bailey Jan 1996

Molecular Systematics Of Red Algae., Jeffrey Craig Bailey

LSU Historical Dissertations and Theses

Phylogenetic analyses of nucleotide sequences for the nuclear-encoded small subunit ribosomal RNA (SSU) gene were used to test current hypotheses of relationships within the Corallinales and among the florideophycidaean orders of red algae. Analyses of SSU gene sequences indicate that the order Corallinales includes four major lineages. The Sporolithaceae is resolved as the earliest-diverging lineage within the order and forms the sister group to a monophyletic Corallinaceae. The molecular data also support the monophyly of the subfamilies Melobesioideae and Corallinoideae. The latter subfamily is inferred as sister to a fourth lineage including non-geniculate and geniculate species classified in the subfamilies …

Go to article

Women Who Lead High Schools: A Missing Element In Leadership Theory., Kristy Brock Hebert Jan 1996

Women Who Lead High Schools: A Missing Element In Leadership Theory., Kristy Brock Hebert

LSU Historical Dissertations and Theses

I addressed the problem that leadership theory is lacking in regard to how women lead high schools. My primary purpose was to contribute to the limited literature that exists regarding the leadership practices of women who are high school principals. I explored the notion of a female culture of school leadership and situated that culture among quintessential theory dictated by organizational research. I conducted this study in two phases. In Phase One I reported the demographics of 44 female high school principals in Louisiana along with their self-reported values on 32 leadership characteristics. Most important to their leadership were: communication, …

Go to article

Role Of Hurricane Disturbance In The Dynamics Of The Southern Mixed Hardwood Forest: A Case Study In Northern Florida., William Bennett Batista Jan 1996

Role Of Hurricane Disturbance In The Dynamics Of The Southern Mixed Hardwood Forest: A Case Study In Northern Florida., William Bennett Batista

LSU Historical Dissertations and Theses

The objective of this dissertation was to characterize the role of hurricanes in the dynamics of old-growth Southern Mixed Hardwood Forests from the coastal plain of the northern Gulf of Mexico. First, we used data from five stands to describe the structure, composition, and disturbance regime of these forests. All five stands have Magnolia grandiflora and Fagus grandifolia among the dominant species, and have been affected by frequent but relatively mild hurricanes (4-6 per century, windspeed $<$200 km/h). Second, we examined the changes in tree recruitment, growth, and mortality occurred in Woodyard Hammock, northern Florida, after this forest was affected by Hurricane Kate in 1985. The analysis was based on data from biennial censuses of a 4.5 ha plot conducted between 1978 and 1992. Hurricane Kate produced extensive canopy disruption but limited tree mortality. This disturbance prompted a phase of increased recruitment, growth, and survival of understory trees, and decreased growth and survival of overstory trees. Release of small understory individuals appeared to be critical for the persistence of three short-lived dominant species, Pinus glabra, Ostrya virginiana and Carpinus caroliniana. However, persistence of the longer-lived dominants Magnolia grandiflora, Fagus grandifolia, Liguidambar styraciflua, Nyssa sylvatica, and Ilex opaca, appeared to depend primarily on resistance to hurricane damage. Third, we used matrix population models to test specific hypotheses about mechanisms of persistence of F. grandifolia in Woodyard Hammock. These models showed that, both before and after Hurricane Kate, this population was close to equilibrium. This result supported the hypothesis that persistence of F. grandifolia has resulted from hurricane resistance. Sensitivity analyses of the models suggested that the key for hurricane resistance has been the high survival of medium-size trees. Life-history strategies involving resistance and survival to hurricane disturbance, rather than release and rapid growth, appear to have been prevalent in these forests. However, the hurricane regime would have resulted in coexistence of species with the two types of strategy. Hurricanes would have been frequent enough to secure the persistence of species dependent on release, and mild enough not to compromise that of species dependent on resistance.

Go to article

The Moderating Effect Of Combinations Of Dissimilar Shoppers' And Sellers' Ethnicities On A Model Of Dyadic Sales Encounters: Shoppers' Perceptions Of Ethnically Different Retail Salespersons., Andrew D. Banasiewicz Jan 1996

The Moderating Effect Of Combinations Of Dissimilar Shoppers' And Sellers' Ethnicities On A Model Of Dyadic Sales Encounters: Shoppers' Perceptions Of Ethnically Different Retail Salespersons., Andrew D. Banasiewicz

LSU Historical Dissertations and Theses

An empirical assessment of the moderating effect of combinations of ethnically dissimilar shoppers and sellers on the nature of retail sales encounters is undertaken. Following the similarity-attraction paradigm (Bochner 1982; Byrne 1961), it is theorized that ethnically similar shoppers and sellers are more attracted to each other than ethnically dissimilar ones, resulting in shoppers' perceptions of sellers' behaviors and personality traits being adversely effected. Operationally, the entire model of sales encounters is moderated by combinations of ethnically dissimilar shoppers and sellers (global moderation hypothesis), or dyadic ethnic dissimilarity. A 2 x 2 experimental design is employed, with the levels of …

Go to article

Immobilization Of P. Digitatum And Bioconversion Of Limonene To Alpha-Terpineol., Qiang Tan Jan 1996

Immobilization Of P. Digitatum And Bioconversion Of Limonene To Alpha-Terpineol., Qiang Tan

LSU Historical Dissertations and Theses

The parameters of bioconversion of limonene to $\alpha$-terpineol by Penicillium digitatum were determined. This bioconversion was carried out stereo-specifically and selectively by this fungus. (R)-(+)-limonene was selectively converted to (R)-(+)-$\alpha$-terpineol by mycelia of this fungus during early growth phase. Immobilization of the fungal mycelia for use in continuous production of this product was possible. Aeration was critical to this bioconversion. The optimum aeration was about 1.6 mg/L for growing cells and immobilized cells. Substrate inhibition of the bioconversion was not observed when the substrate concentration was below 4% (v/v). End product inhibition was observed. The $\rm Ki\sb{app}$ was 12.08 mM. …

Go to article

Reduction And Management Of Vibrio Vulnificus In Gulf Coast Oyster (Crassostrea Virginica)., Yu-Pin Chen Jan 1996

Reduction And Management Of Vibrio Vulnificus In Gulf Coast Oyster (Crassostrea Virginica)., Yu-Pin Chen

LSU Historical Dissertations and Theses

The AmeriPure Process (AmeriPure Oyster Company, New Orleans, Louisiana), which is a mild heat treatment for a specific time period, proved effective in eliminating Vibrio vulnificus from the Gulf Coast oysters (Crassostrea virginica), thus reducing the risk of possible V. vulnificus infections. The treatment was effective in the reduction of V. vulnificus in both $1.5\times10\sp5$ MPN/g (high artificially contaminated level) and $2.4\times10\sp3$ MPN/g (low artificially contaminated level) to undetectable level (MPN $<$ 3/g). The mild heat treatment also reduced naturally occurring V. vulnificus $(8.9\pm3.7\times10\sp4$ MPN/g) present in shellstock oysters harvested in warmer months to undetectable levels. The D value for V. vulnificus present in shellstock oyster averaged 45.6 $\pm$ 3.3 seconds at the AmeriPure Process temperature. Mild heat treatment can also control aerobic plate count numbers during refrigerated storage (0-2$\sp\circ$C) and extend the shelf-life of raw oysters for at least 7 days over unprocessed samples. Mild heat treated oysters need to be refrigerated (${<}4\sp\circ$C) to ensure the safety and quality, as well as shelf-life. Oysters treated according to the AmeriPure Process when exposed to an average room temperature of 27$\sp\circ$C were found unacceptable after 24 hours due to the high number of aerobic plate count (10$\sp7$ CFU/g) and were considered not safe to eat. Although there was a slight lightening in color, sensory panels, composed of both traditional raw oyster consumers and infrequent consumers, found the treated product to be comparable in flavor, texture and smell to untreated oysters. According to the result of sensory evaluation, the good oyster flavor of treated samples increased and the off-flavor and off-odor of the treated oysters were significantly lower than the control samples after 7 days of storage on ice. Possible temperature variations, which could occur during the transportation and storage were studied in a temperature abuse study. The result showed that no Vibrio vulnificus was recovered and no significant microbiological quality change was observed after 10 hours of exposure to the room temperature of $22\pm2\sp\circ$C.

Go to article

First Prev Next Last