Thesis (Ph.D.)--University of Hong Kong, 1981. / Also available in print.

I investigated plant and animal community characteristics on 14 forest stands in north central Mississippi. Study sites included 9 pine plantations, 3 streamside management zones, and 2 hardwood cove forests. I estimated relationships between faunal metrics and habitat characteristics. I measured vegetation characteristics within quadrant and nested plot designs to estimate understory, midstory, and overstory species composition and structure. I inventoried breeding birds using point count surveys and sampled herpetofauna diversity using area-constrained searches within belt transects during 2008 and 2009. I detected 39 species of birds in 2008, 43 species of birds in 2009, 11 species of amphibians, and 9 species of reptiles. Hardwood cove sites supported more deep forest-dwelling bird and salamander species; whereas, pine stands supported more grassland bird species. Species richness and abundance of birds was related to snag DBH. Species richness and abundance of herpetofauna was related to number of understory plant species.

With the assistance of information collected by residents of Bumpass Cove, Tennessee Department of Public Health records, and interviews with residents and local health officials, this study provides a historical overview of the inception of Bumpass Cove Landfill, the resulting problems stemming from its misuse, and the reaction of a persistent community during the 1970s and early 1980s. In its early days, Bumpass Cove was an active and productive mining site; however, the area would become a threat to the local residents’ safety with the opening of Bumpass Cove Sanitary Landfill. Years of illegal hazardous waste land filling wreaked havoc on the environment and endangered area residents’ health. In the end, citizen protest and the intervention of the Superfund Program would result in the closing of the landfill and the restoration of the area. Taken together, these occurrences paint a vivid picture of the controversy surrounding Bumpass Cove Landfill.

This study addressed the geochemical drivers of Mn removal, including pH, alkalinity and the presence of mineral particles. We conducted laboratory experiments and field monitoring at two drinking water reservoirs in southwestern Virginia – Falling Creek Reservoir (FCR) and Carvins Cove Reservoir (CCR). In laboratory experiments in pH and alkalinity-adjusted nanopure water solutions, we observed substantial Mn removal within 14 days only under high pH conditions (pH≥10). In experiments with high pH and moderate to high alkalinity (> 80 mg/L CaCO3), near-total Mn removal occurred within 2 hours, at a rate of 0.25 mg/L-1 hr-1. Mn removal occurred alongside precipitation of microscopic (<5 μm diameter) and macroscopic (>100 μm diameter) particles. Elemental analysis of particles with energy-dispersive X-ray spectroscopy (EDS) supports their identification as Mn(IV) oxides (MnOx), which suggests Mn removal driven by oxidation. Elevated alkalinity in high pH solutions promotes Mn oxidation by maintaining high pH through buffering, which sustains conditions favorable for Mn oxidation. Our results also suggest sorption of Mn and mineral-catalyzed Mn oxidation by Mn oxides formed through oxidation by dissolved oxygen. In experiments using filtered and unfiltered water from the two reservoirs, we observed significant Mn removal in experiments with unfiltered water, suggesting that particles may remove Mn by catalyzing oxidation or nucleating Mn oxide precipitation. Mn removal occurred at 0.05 d-1 in unfiltered FCR water and 0.002 d-1 in unfiltered CCR water. We observed no Mn removal in filtered water from either reservoir. Scanning electron microscope (SEM) and EDS of visible particles from reservoir water experiments suggests that quartz and clay minerals present in the water column may nucleate or catalyze Mn oxide formation. Overall, this research shows that Mn removal under HOx operation is influenced by a variety of factors, including pH, alkalinity and suspended particles. / Master of Science / Elevated concentrations of manganese (Mn), a naturally occurring contaminant, can impair drinking water quality in several ways – by introducing poor taste and smell, staining pipes and appliances, and potentially harming the health of young children. Hypolimnetic oxygenation (HOx) is a novel water treatment method deployed in lakes and reservoirs to control water column contamination of metals and nutrients, including Mn. By pumping oxygen into lakes and reservoirs, HOx systems create conditions favorable for Mn removal from the water column. Previous work in two southwestern Virginia drinking water reservoirs documented differences between sites in how effectively HOx systems are able to remove Mn. These reservoirs have significant differences in their chemical profiles – most notably in pH and alkalinity, which suggests a role for background water chemistry in influencing removal rates in lakes and reservoirs with HOx systems. We used laboratory experiments to simulate the effects of pH and alkalinity on Mn removal rates in oxygenated lakes and reservoirs. We observed substantial Mn removal within 14 days under high pH conditions (pH 10-11) and negligible removal in solutions at or under pH 8. In experiments with pH 10-11 and alkalinity over 80 mg/L, near-total Mn removal occurred within 24 hours. During the 24 hour removal window, we observed yellow-brown discoloration of our experimental solutions within 12 hours, followed by formation of loosely aggregated brown to black particles. Microscopy and elemental analyses indicate that initial discoloration occurs due to formation of 1-2 μm wide manganese oxides with needle-like crystals. The visible aggregates are also manganese oxides. Based on mineral characterization and the time series of Mn removal observed in our experiments, we believe that initial formation of Mn oxides creates a positive feedback loop in solutions of pH 10-11 and alkalinity over 80 mg/L. Mn oxides promote further Mn oxide formation by facilitating conversion of Mn in solution into forms that easily settle from water. Observations of particulate formation and solution chemistry in filtered vs. filtered reservoir water from FCR and CCR supports a pivotal role for particles in facilitating Mn removal. Our research addresses the impacts of water chemistry Mn removal in drinking water, and improves understanding of Mn cycling in natural freshwaters.

No description available.

The purpose of this study was to compare vegetation systems among three artificially isolated wetlands on the west end of Galveston Island. Sample sites were identified as isolated wetlands and anthropogenic impact was observed. Wetland plant communities were identified through representative field studies using a modified quadrat method. Species composition, species diversity, evenness, cover and frequency were compared among the three sample sites. Salinity at all three sample sites remained at 0 ppt through June, July and August. Salinity increased to 10 ppt in both Lafitte’s Cove Nature Preserve and Dos Vacas Muertas Bird Sanctuary in September. No change in salinity was recorded at Isla Del Sol. At Lafitte’s Cove Nature Preserve the majority of the soil composition included Mustang-Nass. Dos Vacas Muertas Bird Sanctuary consisted of a Mustang fine sand complex while Isla Del Sol consisted of Mustang fine sand and Nass very fine sandy loam. Sampling at Lafitte’s Cove Nature Preserve produced 15 species. Dos Vacas Muertas Bird Sanctuary added 7 new species while Isla Del sol added 6 new species for a total of 28 species within the three sites. The overall plant species’ richness of Lafitte’s Cove Nature Preserve and Dos Vacas Muertas Bird Sanctuary remained low. A high frequency was observed in Sesbania drummondii and Cyperus odoratus at Lafitte’s Cove Nature Preserve. Sesbania drummondii retained the highest percent cover for the site. At Dos Vacas Muertas Bird Sanctuary, Phragmites australis and Spartina patens demonstrated a high frequency as well as percent cover. Frequency was highest in Juncus roemerianus and Eleocharis geniculata at Isla Del Sol. Several plant species exhibited a high frequency while overall frequency was more evenly distributed in Isla Del Sol than the other sample sites. Percent cover was highest in Juncus roemerianus and Borrichia frutescens. Isla Del Sol had the highest species diversity and evenness of all three sample sites. Similarity in species composition was high with the coefficient for pair-wise comparisons in Isla Del Sol and Lafitte’s Cove Nature Preserve being the highest. The three sample sites shared 53% to 73% of their species. Isla Del Sol possessed 6 species that were absent from the other sample sites. Dos Vacas Muertas Bird Sanctuary contained 4 unique species while Lafitte’s Cove Nature Preserve had only 3 unique species. Dos Vacas Muertas Bird Sanctuary had the lowest index score at 10. Lafitte’s Cove Nature Preserve had the highest index score at 24 while Isla Del Sol followed close behind at 22. For the Anthropogenic Activity Index, Lafitte’s Cove Nature Preserve still retained the highest score at 14. Results for Isla Del Sol showed an index score of 13 while Dos Vacas Muertas Bird Sanctuary scored only 7. The results of this study show that although Dos Vacas Muertas Bird Sanctuary had lower levels of disturbance when compared to the other sample sites, it still experienced a lower species diversity. Isla Del Sol had the highest species diversity and evenness of the sites. Lafitte’s Cove Nature Preserve had the highest level of disturbance and maintained a low level of diversity as well. When comparing the results to historical data, a reduction in salt marsh plant species was observed. Species that are often associated with freshwater to brackish marsh wetlands have become more dominant in the sample sites.

Thesis (M. Sc.)--University of Hong Kong, 1995. / Includes bibliographical references (leaves 78-80).

Thesis (M.A.)--Memorial University of Newfoundland, 2006. / Bibliography: leaves 105-114. Also available online.

A comparison of the spoken language of adolescent Black males living in three southern suburban communities was conducted. The results indicated certain trends by locale in the areas of morphology, phonology, syntax and semantics. The findings affirm the assumption that it is possible to determine likenesses and differences in the Black English spoken by Black males living in three isolated communities with a rating instrument.

Made available in DSpace on 2016-01-26T18:56:25Z (GMT). No. of bitstreams: 1 DISSERTACAO_AGRONOMIA_Oscar_mar07_novo1.pdf: 270672 bytes, checksum: 7eba03f64317fd976224aae8616283fc (MD5) Previous issue date: 2006-01-31 / The cassava (Manihot esculenta Crantz) is currently of great economic and social importance for Brazil. Important factors for evaluation of cassava cultivars under field conditions are: productivity (mg ha-1); Dry Matter Percentage (MS%). In order to carry out nutritional evaluation the following parameters must be considered: Fat - Ethereal Extract (EE%); Ash (%); Gross Digective Fiber (FB%); Gross Protein (PB%); Non Nitrogenate Extrative (ENN%) and Total Digestive Nutrient (NDT). The aim of this study was to verify differences between 16 cassava cultivars cultivates whit differents spacements: 0,60 m and 0,80 m whithin the line and 0,90 m between lines. The experimental design performed in random blocks with some treatments in common, with four repetitions. The results showed that the cultivars Espeto; Eucalipto e IAC 144-86 obtained smaller productivities. The cultivars Iracema; IAC 184-89; Fibra; IAC 89-87; Fécula Branca; IAC 32-88; IAC 14; Olho Junto; Mico; IAC 12; IAC 169-86; IAC 5-88; IAC 15 showed the highest yields. The bromatological characteristics didn't present statistical differences. The among cultivars 0,60m in the spacement increased the productivity in 12% when compared to the 0,80m spacement. / A mandioca (Manihot Esculenta Crantz) é atualmente de grande importância econômica e social para o Brasil. Fatores importantes para avaliação de cultivares de mandioca a campo são: produtividade (Mg ha-1) e o teor de Matéria Seca (MS%). Para avaliação nutricional deve-se atentar para: Gordura Extrato Etéreo (EE%); Cinza (%); Fibra Bruta (FB%); Proteína Bruta (PB%); Extrativo Não Nitrogenado (ENN%) e Nutrientes Digestivo Totais (NDT%). O presente trabalho objetivou estudar as diferenças entre cultivares de mandioca, com espaçamentos de 0,60m e 0,80m na linha e 0,90m na entre linhas. O delineamento experimental utilizado foi análise conjunta de experimentos em blocos ao acaso com alguns tratamentos em comuns, com quatro repetições. Conclui-se, no presente ensaio que as cultivares Espeto; Eucalipto e IAC 144-86, obtiveram menores produtividades estatisticamente; As cultivares Iracema; IAC 184-89; Fibra; IAC 89-87; Fécula Branca; IAC 32-88; IAC 14; Olho Junto; Mico; IAC 12; IAC 169-86; IAC 5-88; IAC 15 obtiveram as melhores produtividades estatisticamente; As características bromatológicas não apresentaram diferenças estatísticas; O espaçamento de 0,60m aumentou a produtividade em 12% quando comparado ao espaçamento de 0,80m