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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Habitat Assessment and Subspecies Identification of Sandhill Cranes Wintering in Louisiana

McGowan, Joseph Michael 31 July 2003 (has links)
The two biggest flocks of Sandhill Cranes (Grus canadensis) wintering in Louisiana are located in Cheneyville and Holmwood, LA. Resident Sandhill Cranes were once located in Louisiana, but because of habitat loss and over harvest these residents were extirpated from Louisiana in the early 1900s. In the 1960s, migrating Sandhill Cranes had returned to LA and were wintering in Cheneyville. Observations and habitat characteristics were conducted on these two flocks in the winter of 2002 and 2003 because of the lack data on these flocks. The two flocks contained about 1,300 individuals with four other known flocks throughout Louisiana ranging from 16-400 individuals. There were an estimated 2,200 Sandhill Cranes wintering in Louisiana. Morphometric measurements for eight birds fell within the range of the Greater Sandhill Crane (G. c. tabida) subspecies. Middle toe imprint measurements in the winter of 2003 showed no difference in size of cranes in the two flocks during January and February, however there was a difference in middle toe size in December. One radio-marked bird was radio tracked to Cheneyville and Holmwood. Cranes selected roost sites in rice fields with water less than 20 cm deep. Cranes feeding in Cheneyville selected rice fields and corn fields, while the Holmwood birds used rice fields and pastures. Fecal analysis showed that nutsedge tubers (Cyperus spp.), rice (Oryza sativa), and corn (Zea maize) were the major foods consumed in Cheneyville, while the Holmwood birds used mostly nutsedge tubers and rice. Rice was found in feces earlier in the winter and nutsedge was found more frequently later in the winter.
2

Macroinvertebrate Abundance and Distribution of Hydrilla and Ceratophyllum Habitats in the Atchafalaya River Basin, Louisiana

Colon-Gaud, Jose Checo 09 June 2003 (has links)
Submerged aquatic vegetation (SAV) plays an important role in aquatic systems, providing shelter, breeding habitat, and epiphytic forage for numerous fishes and aquatic macroinvertebrates. Since 1960, many lentic habitats in the southern U.S. have been invaded by Hydrilla verticillata, and in the last two decades this aggressive macrophyte has become the dominant species of SAV in the Atchafalaya River Basin in south central Louisiana. Because of its highly branched morphology and characteristically high densities, I found it difficult to quantitatively sample the macrofauna inhabiting hydrilla stands with traditional gears such as sweep nets, particularly under the canopy. As a consequence, I developed a suitcase trap that provided an efficient, quantitative method of sampling hydrilla-associated macroinvertebrates, and compared the abundance and taxonomic composition of samples collected with suitcase and sweep net samplers in dense hydrilla habitat. The suitcase trap is easy to deploy and retrieve, effective in all plant densities, permits estimation of macroinvertebrate densities by plant volume or dry weight, and is more effective than traditional sweep nets in describing the vertical distribution of macroinvertebrates inhabiting hydrilla-dominated littoral habitats. To provide a better understanding of the effects of exotic macrophyte invasions on the ecology of epiphytic invertebrates, and to identify possible management alternatives to mitigate detrimental impacts associated with these invasions on littoral habitat quality, I measured the density of vegetation-dwelling macroinvertebrates on exotic Hydrilla verticillata and native Ceratophyllum demersum in the Atchafalaya Basin. I collected a total of 34,996 macroinvertebrates from hydrilla and coontail habitat from May to August 2001 to determine how exotic hydrilla compares to native macrophytes in terms of macroinvertebrate habitat. Abundant macroinvertebrate taxa included Amphipoda, Decapoda, Diptera, Gastropoda, and Ephemeroptera. Overall, macroinvertebrate abundance between hydrilla and coontail was relatively similar. It is apparent from this study that, at least at the assemblage level, differences between abundance and distribution patterns of macroinvertebrates in different macrophyte species do exist. Principal component analysis displayed differences between macroinvertebrate assemblages, although the relative effects (and interactions) of declining or fluctuating water quality, macrophyte architecture, food resource quantity and quality, and predatory mortality on macroinvertebrate community composition remain to be identified.
3

Do Terraces and Coconut Mats Affect Seeds and Submerged Aquatic Vegetaion at Sabine National Wildlife Refuge?

Caldwell, Aaron Bailey 26 June 2003 (has links)
<p class=MsoNormal style='text-indent:.5in;line-height:200%'>Terraces are a widely used wetland restoration tools in coastal Louisiana, yet the benefits of terraces are poorly documented.<span style='mso-spacerun:yes'> </span>Like terraces, coconut mats also may increase abundance of submerged aquatic vegetation (SAV), but their benefits are undocumented.<span style='mso-spacerun:yes'> </span>I compared SAV and seed abundance in a marsh pond among three treatments: terrace, coconut mat, and marsh.<span style='mso-spacerun:yes'> </span></p> <p class=MsoNormal style='text-indent:.5in;line-height:200%'>I evaluated terraces constructed in 1999 and coconut mats installed in 2001 in portions of unit 7 of Sabine National Wildlife Refuge that converted from emergent marsh to open water between 1956 and 1978. I randomly selected 3 terrace, marsh, and coconut mat stations. I evaluated transects 0 meters, 5 meters, and 50 meters (here after open water) from emergent vegetation at each station.<span style='mso-spacerun:yes'> </span>Submerged aquatic vegetation was evaluated on the terrace and marsh by harvesting SAV from 10-cm diameter cores, harvesting SAV from 1-m<sup>2</sup> plots, and raking: only 1-m<sup>2</sup> plot sampling was conducted on coconut mat treatments. I evaluated seed abundance on terrace and marsh transects with 10-cm diameter cores, which could not be used on the coconut mats.</p> <p class=MsoNormal style='text-indent:.5in;line-height:200%'>Submerged aquatic vegetation biomass differed between treatments and sampling dates. Biomass of SAV, as estimated by the cores, was greater on the marsh transects than the terrace transects. The SAV biomass, as estimated by 1-m<sup>2</sup> plots, was greatest during September 2002. Biomass of SAV, as estimated by 1-m<sup>2</sup> plots, was greater on coconut mats than terrace or marsh transects. Raking indicated that in September 2002, the percent occurrence of SAV was greater on the marsh transects than on the terrace transects.</p> <p class=MsoNormal style='text-indent:.5in;line-height:200%'>Seed biomass was greater adjacent to marsh than to terraces, which was similar to that in open water. Seeds of sawgrass (<i style='mso-bidi-font-style:normal'>Cladium jamaicense </i>Crantz) accounted for 87% of the seed biomass but did not germinate in a greenhouse.</p> <p class=MsoNormal style='text-indent:.5in;line-height:200%'>My results indicated that terraces failed to increase SAV abundance above levels found in open water as was predicted. I concluded that restoration planners should no longer assume that terraces increase SAV abundance. Coconut mats increased SAV abundance. Additional studies on a variety of areas and configurations are needed to determine if my observations are typical.</p>
4

Ultrasonic Characterization of Engineering Performance of Oriented Strandboard

Vun, Ronnie Yunheu 09 July 2003 (has links)
Direct-contact (DC) and non-contact (NC) ultrasonic transmission (UT) methods were developed to characterize the structural performance of oriented strandboard (OSB). The UT variable velocity was shown to be sensitive to the physical impediments caused by flake interfacial boundaries and embedded voids. Both attenuation and root mean square (RMS) voltage were good indicators of the zero void densification level for OSB, a point of the greatest transmissivity of the stress wave energy. For both DC and NC methods, the predicted densities of the model were validated for spatial distribution over each OSB type. Based on the EN300 standard for panel manufacturing, the control limits were ±10% of the panel average density. The density prediction was found to improve with higher resin content (RC) and higher nominal density (ND) levels. From the out-of-limits plots, the predicted in-situ densities produced a reasonably spatial coherence to the measured values. All panels made with ND 0.60 g/cm3 or greater conformed well within the limits, with declining conformity towards lower RC panels. For each composite type made of different particle sizes, the equilibrium moisture content showed a decreasing trend toward smaller particle panels. The attenuation and RMS were good indicators for moisture change and densification level for each composite type. The velocity, sensitive to physical resistance of particle sizes, increased with increasing IB strength and sample density, manifesting the positive influence of layering, resin content, and the negative effect of bark as a constituent. The results of the creep rupture tests on commercial OSB using an acoustic emission (AE) technique indicated that the cumulative AE event count parameter was highly correlated with deflection parameter and appropriately represented the accumulation of incipient damage. Under high stress levels, specimens with high moisture content (MC) sustained the worse damages having the shortest creep rupture time followed by specimens with dynamically rising MC. Defects on the compression-side of the bending specimen were found critical to creep rupture than those on the tension-side. The in-plane fracture patterns tended to follow the defect trenches of low-density valleys, and worsened with greater variability of the horizontal density, indicating the need to measure and control the horizontal density variation within reasonable limits.
5

Effects of Selective Herbicide Application on Vegetation and Invertebrates for Northern Bobwhite, and Small Mammal Communities within Managed Pine Forests

Jones, Judy Diane James 10 July 2003 (has links)
Decline of northern bobwhite (Colinus virginianus) populations during the past 30 years in southern portions of their range has increased efforts to improve habitat quality by integration of wildlife and forest management. Prescribed burns and herbicides have potential to benefit bobwhites, vegetation, invertebrates, and small mammal communities in pine-dominated systems. This study was conducted at 700-hectare Louisiana State University Idlewild Research Station of LSU's Agricultural Center in East Feliciana Parish. The experiment was conducted on 3, 10.12-hectare, 75 to 85 year-old, over-mature, uneven-aged pine stands on hilltops and sloping terrain. Experimental design included vegetation, invertebrate, and small mammal response to 3 treatments of 2 types of selective herbicide (imazapyr, imazapyr + glyphosate) and a control applied after an initial prescribed burn. Each stand served as whole plots and treatments as subplots within a split-plot arrangement. Treatments were randomly assigned and replicated across 3 stands. Herbicide treatments were more effective at improving vegetational structure for brood-rearing and nesting bobwhites. Plant and invertebrate species diversity declined on herbicide treatments during the first year, but increased on imazapyr plots during the second year. Bobwhite food plants increased on imazapyr plots for the first year and were greater on both herbicide treatments the second year. Herbicides reduced sweetgum but neither negatively affected hard mast producing species > 10 cm dbh. High overstory canopy closure and drought conditions may have negatively affected vegetation response. Herbicides did not produce bare ground percentages preferred by bobwhites. Prescribed burn alone created and maintained escape cover more suitable for bobwhites. Overall, imazapyr provided greater benefits to bobwhite, retained floristic species diversity, and greatly improved invertebrate diversity. Small mammal abundance increased on herbicide treatments presumably because of changes in vegetational characteristics and communities, and increased plant and invertebrate diversity on imazapyr treatments. Additionally, Peromyscus species was most common mammal trapped on all plots. Future research should evaluate vegetative response to herbicides under variable canopy conditions and different imazapyr application rates. We recommend managers target areas where prescribed burns are not possible and apply imazapyr strategically to create diverse, patchy habitat.
6

Impact of Corporate Orientation on Information Technology Adoption in the United States Forest Products Industry

Poku, Kofi 02 July 2003 (has links)
This study aims to contribute to addressing the gap that exists in determining the role an organizations internal operations play in information technology (IT) adoption in organizations. In particular, this research stems from investigating the relationship between company success at adopting information technology systems (the Internet) in the United States forest products industry (specifically, the lumber sector) and the extent to which organizational orientation within the industry supports the development. Following an extensive literature review, a conceptual model that represents the synthesis of information technology adoption-marketing orientation influences is developed. (This study does not infer that a company can acquire only one orientation at any one time). The United States forest products industry has traditionally been perceived as being production-oriented by many researchers. Marketing orientation, however, is a relatively new phenomenon that is gradually seeping into the way the industry does business as a result of competition, technology advancement, and the changing needs of consumers. Consequently, a number of propositions are tested and managerial and research recommendations are put forward. Overall, this research finds that email and the World Wide Web are the two most popular internet-based applications used by companies in the lumber industry. A positive relationship exists between factors of Internet adoption (extent of Internet application, user participation, perceived ease of use by user, perceived usefulness by user, and adoption diffusion by company) and perceived company effectiveness of Internet adoption under high and low marketing orientation, with a higher rate of increase in high marketing orientation than low marketing orientation.
7

Physicochemical Effects on the Abundance and Distribution of Larval Fishes in the Atchafalaya River Basin, Louisiana

Engel, Matthew Aaron 10 July 2003 (has links)
The Atchafalaya River Basin (ARB) experiences overbank inundations as springtime temperatures warm that create conditions favorable for bacterial respiration, which results in hypoxic conditions (dissolved oxygen [DO] ≤ 2.0 mg/L). Previous ARB research has shown that pelagic larval fish populations are impacted by hypoxic conditions, and that larvae may use macrophyte beds (e.g., hydrilla Hydrilla verticillata) as DO refugia. I examined the relationship between physicochemistry and the distribution and abundance or larval fishes associated with ARB macrophyte beds during 2001-2002. Larval fishes were collected with light traps at two normoxic and hypoxic sites, and at each site, surface and subsurface traps were placed in open channels, hydrilla beds, and the interface between the channel and macrophyte beds (border). Of the 1,718 larval fishes representing 10 families that were collected, centrarchids Lepomis spp. (45.5%) and catostomids Ictiobus spp. (25.7%) dominated the 2001 assemblage, whereas percids Etheostoma spp. (29.1%) and centrarchids (17.8%) were most abundant in 2002. River stages between years were different from each other (P < 0.001), and from the 42-year stage average (P < 0.001). Between-year differences in flood pulse timing and duration resulted in higher pH, temperature, and DO levels, and 2.5 times more larval fishes in 2001. Overall, larval fish abundances under hypoxic conditions were severely reduced during both years. Under normoxic conditions, larval fishes were collected from all habitats, but were typically in higher abundance in nearshore areas regardless of cover conditions (hydrilla vs. no cover). Larvae that could withstand hypoxic conditions (centrarchids, clupeids, cyprinids, and percids) were typically found in nearshore areas associated with hydrilla beds. Because of the increased abundance of predatory invertebrates in these areas, the use of hydrilla beds by fish larvae as oxygen refugia may provide optimal physiochemical conditions at an increased predation risk. Man-made alterations in the ARB have changed circulation patterns on the inundated floodplain, which contribute to seasonally widespread hypoxic conditions and reductions in larval fish abundance. Thus, any management plan that increases the historic connection between the mainstem Atchafalaya River and the floodplain, and improves floodplain circulation would benefit larval fish production in the ARB.
8

Establishment of a Callus Culture and Measurement of Seasonal Changes in Secondary Compound Production in Eucommia ulmoides Oliver

Gray, Erica Deshay 11 July 2003 (has links)
Eucommia ulmoides Oliver (Eucommiaceae) contains many secondary metabolites, including the lignan pinoresinol di-O-β] glucoside (PG) and the iridoid glycoside aucubin (AU), which have been shown to have anti-hypertensive, antioxidant, and hepatoprotective biological properties. The main objective of this research was to create a new agricultural crop in Louisiana for maintaining healthy blood pressure levels. This was done by: 1) determining the seasonal changes in the concentrations of PG and AU in four-year-old E. ulmoides trees in cultivation in Baton Rouge, Louisiana using Thin Layer Chromatography and High Pressure Liquid Chromatography (HPLC) and 2) determining production of secondary metabolites of E. ulmoides leaf tissue within callus culture using HPLC. While AU was produced within the cortex and leaves of cultivated trees, PG was not detected. AU was produced year round in both cortex and leaves, except for December and February when leaf abscission occurs. AU was measured in all of the monthly cortex samples, with the April 2001 sample yielding the highest concentration (1.42 μg/g). AU concentrations in June, August, and April 2002 leaf samples were not statistically different (p<0.05). Four levels of NAA (0, 3, 6, 9 mg/l) and BA (0, 1, 2, 4 mg/l) were used to induce callus cells from E. ulmoides leaves. AU was not detected by HPLC, but PG was found to be present in 13 of the 16 treatments. A ratio of 3 mg/l NAA to 4 mg/l BA produced the highest PG concentration. The information gained from this data can be used to determine an efficient harvesting scheme for the extraction of secondary metabolites produced by Eucommia ulmoides.
9

From Gamete Collection to Database Development: Development of a Model Cryopreserved Germplasm Repository for Aquatic Species with Emphasis on Sturgeon

Wayman, William Rittenhouse 10 July 2003 (has links)
Development of a cryopreserved sperm repository could greatly benefit the study and recovery of endangered species. Currently, a national repository for endangered aquatic species does not exist. This dissertation addressed the development of methods for the creation of a model germplasm repository, which included methods to reduce bacterial contamination within sperm samples, verify sample identification, store sperm (refrigerated or cryopreserved), evaluate sperm quality before and after thawing, and maintain sample and broodstock information. Although these methods were developed for sturgeon, they could be adapted for any aquatic species. Accurate species identification of sperm samples is essential for an archival repository. A polymerase chain reaction and restriction digest method was developed to identify three sturgeon species, and separate the remaining species into distinct groups. Bacterial contamination of sperm samples can lead to sample deterioration and transmission of pathogens. Twenty-seven species of bacteria from 15 genera were isolated from sperm samples of sturgeon in this study. Addition of antibiotics did not lengthen refrigerated storage time. Cryopreservation procedures developed for sturgeon sperm did not reduce bacterial numbers in thawed samples compared to pre-freeze numbers. Seminal plasma osmolality (100 mOsmol/kg) and sperm activation data (reduction in potassium ion concentration) were used to develop extenders. Hanks balanced salt solution or modified Hanks balanced salt solution (mHBSS) at 100 mOsmol/kg allowed refrigerated storage of sperm for as long as 21 d. Sperm were cryopreserved using mHBSS (100 mOsmol/kg), methanol (5% or 10%), a cooling rate of 22-24 oC/min, and 0.5-ml straws. A dual-staining flow cytometry technique was used to determine gamete quality in sperm samples before and after thawing. The procedure was validated by evaluating membrane integrity in mixed populations of untreated cells and heat-treated membrane damaged cells. When used with thawed samples, whenever membrane integrity was correlated (r2 > 0.8068) to percent fertilization and hatch, motility was also correlated (r2 > 0.7650) to percent fertilization and hatch. A computer database was developed using MicrosoftÒ Access to maintain inventory and quality control of sample information. The database is currently being used at the Warm Springs Fish Technology Center of the United States Fish and Wildlife Service.
10

Evaluation of Government Interventions in Ghana's Forest Product Trade: A Post-Intervention Impact Assessment and Perceptions of Marketing Implications

Donkor, Ben Nathan 26 August 2003 (has links)
Since the mid 1990s Ghana's forestry sector has been going through reforms geared towards achieving the ITTO Year 2000 Objective for sustainable forest management and forest product trade. The reforms were partly introduced through legal approaches and also through activities under a long-term Forestry Sector Development Master Plan. The legal approaches mainly dealt with strengthening of sector institutions to effectively carry out forest concession administration and management, stumpage fee increases and more punitive actions against forest offences. Reforms with more direct impact on forest product export trade came through the implementation of the Forestry Sector Development Master Plan - reduction in annual allowable cut (AAC), introduction of air-dry levy, and promotion of value-addition and lesser-used species (LUS). These actions have infuriated the forest product industry blaming the government for a collapsing industry as a result of the interventions. This study evaluated the impacts of the interventions believed to be directly affecting the forest product export trade and perceptions of marketing implications. The study concluded that: - 1. The drop in raw material level has influenced increasing export of kiln-dried lumber and processed lumber molding. The air-dry levy is observed to be working well as a disincentive to export of commodity products by reducing export of air-dried lumber and increasing kiln-dried lumber and sliced veneer. 2. The air-dry levy showed a significant effect with an increase in percent of LUS (used as a measure of species diversification) exported in the post-intervention time period. 3. There is the need to improve machinery upgrade to include CNC technologies, relationship with buyers, strengthening of wood inspection authority, flexibility in terms of trade, Internet capabilities, and financial support to the industry.

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