Physical Sciences and Mathematics Commons^™

A Reexamination Of The Eastern Collared Lizard (Crotaphytus Collaris Collaris) In Arkansas, Ashley A. Grimsley

Graduate Theses and Dissertations

Loss of suitable habitat is a threat to species worldwide. Habitat destruction, including loss, change, and fragmentation of habitat, is the leading cause of species extinction. Eastern collared lizards (Crotaphytus collaris collaris) are habitat specialists on glades. Both C. c. collaris and glade habitats are rare and of special concern in the state of Arkansas. Many glade populations have already been extirpated in the Ozarks of Arkansas and Missouri. Increasing knowledge of the distribution, habitat structure, and population dynamics of C. c. collaris is important to ensure the survival of this species in Arkansas.

A literature review of …

Biological Strategies And Mathematical Approaches For Limiting Bacterial Contaminants And Chemical Pollutants In Bioethanol Fermentations, Alia Chahed Ep Limayem

Graduate Theses and Dissertations

During the most recent decades increased interest in fuel from biomass in the United States and worldwide has emerged each time petroleum derived-gasoline registered well publicized spikes in price. The willingness of the U.S. government to face the issues of more heavily high-priced foreign oil and climate change has led to more investment on plant-derived sustainable biofuel sources. Biomass derived from corn has become one of the primary feedstocks for bioethanol production for the past several years in the U.S. However, the argument of whether to use food as biofuel has led to a search for alternative non-food sources. Consequently, …

Territories,Territoriality, And Conservation Of The Louisiana Waterthrush And Its Habitat, The Watershed Of The Upper Buffalo National River, Leesia Cheryl Marshall

Graduate Theses and Dissertations

The Louisiana Waterthrush, Parkesia motacilla, is a migratory wood-warbler and breeding season resident of the eastern United States. Males defend breeding territories that extend linearly along clear, fast-flowing, gravel-bottomed, forest streams. Defense includes two song types, primary and extended song. As riverine specialists, birds rely upon aquatic invertebrates as prey and riparian habitat features for nesting. They use a unique foraging maneuver, leaf-pulling, that involves picking up or pulling a leaf from water, and turning it over to search for prey. Their relationship with riparian habitat introduces potential for Louisiana Waterthrushes to serve as indicators of stream health. The …

The Use Of Diatoms To Infer Environmental Change Of The Lower White River, Southeastern Arkansas, Ruchi Bhattacharya

Graduate Theses and Dissertations

This dissertation describes the limnology of the lower White River oxbow lakes in southeast Arkansas, inundated by the major 2008 spring flood. The flood water and sediment deposited in oxbow lakes were analyzed for water chemistry, sediment geochemistry and diatom assemblages and used as an analogue for past floods. The 2008 spring flood inundated and homogenized the entire floodplain; also represented by the predominantly planktonic diatom assemblage suggesting riverine input. Indicator species for eutrophication were also recorded consistent with the high nutrient content in the lakes. However, the variance in the surface diatom assemblage was best explained by the lake …

Integrating Human Variables In Cross-Boundary Monitoring Of Aberdare Preserves In Kenya, Peter K. Njuguna

Graduate Theses and Dissertations

This research critically examines extant data systems and their linkage of scientific research to policy and public education in east African highland forest conservation preserves. The research indicates that the current state of data and monitoring systems in the region imposes substantial limitations on the ability to manage these preserves. Major outcomes of those constraints manifest in unprecedented cross-boundary pressure such as encroachment and conversion of forest to agriculture, increased human-wildlife conflicts, and constrained relations among primary stakeholders. Current monitoring is biodiversity focused within preserves and fails to capture human dimensions in adjoining areas across preserve boundaries. This study proposes …

Nitrogen Retention And Denitrification In Reservoirs, Erin Grantz

Graduate Theses and Dissertations

Studies coupling direct measurements of micro-scale nitrogen (N) cycle processes with ecosystem-scale flux estimates are needed to determine N retention hotspots within river networks, where up to 50% of terrestrial loading to aquatic systems is retained. This study examined the role of denitrification, a microbially-mediated reactive N removal pathway, in ecosystem-scale N retention in 3 small (< 1 km2), shallow flood-control reservoirs. Annual reservoir N retention was estimated through mass balance modeling of system inputs and outputs. Annual denitrification rates were estimated by combining multiple measurements of seasonal, habitat-specific dinitrogen gas (N2) fluxes. Annual reservoir N retention ranged from 14 - 19 g m-2 in the reservoirs, while reactive N removal through denitrification was 13 - 25 g m-2. Denitrification efficiency, or the portion of the retained N load that was denitrified, was high relative to other lentic systems and was > 100% at 2 sites. Previous lentic denitrification studies may have underestimated denitrification efficiency by not considering water column denitrification, which was 50% of total denitrification at one study reservoir. However, not all potential inputs, most importantly biological N2 fixation, were included in this …

Subcritical Water Hydrolysis Of Whey Proteins, Ashley Dawn Espinoza

Graduate Theses and Dissertations

Hydrolyzing food by-products is a unique approach to potentially increase by-product value and reduce waste. An abundant by-product of cheese production, whey, contains all essential amino acids and some distinctive peptides with functional and nutraceutical properties. Typically, proteins from whey are tailored for specific uses by chemical or enzymatic hydrolysis; however, subcritical water hydrolysis is a novel alternative used successfully to hydrolyze various substrates. Nevertheless, minimal research exists on: (1) the hydrolysis of whey protein; (2) the incorporation of additives; (3) the hydrolysis of whole whey; and (4) the production of volatiles when using subcritical water hydrolysis.

Therefore, whey protein …

Analyzing Spring Freeze Impacts On Deciduous Forest Productivity Using Modis Satellite Imagery, Karl Lintvedt

Graduate Theses and Dissertations

The impacts of an April 2007 spring freeze event on the productivity of deciduous broadleaf forest were analyzed using geographic information system (GIS) tools. Forest productivity was modeled using the Enhanced Vegetation Index (EVI), as recorded by the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensor. Measures of spatial autocorrelation were used to quantify the degree of spatial congruence between a map depicting the severity of the freeze event, and maps modeling forest productivity throughout the year. The results show a geographic correlation between the unseasonably low minimum temperatures sustained during the freeze and the unusually low forest productivity that followed. …

Assessing Ageing At Beaver Reservoir, Northwest Arkansas: Limnological, Geochemical & Paleolimnological Approach, Byron Anthony Winston

Graduate Theses and Dissertations

Access to potable water has been arguably one of the most important requisites for the advancement of human civilization on earth. As a result, man in his infinite wisdom devised the dam and formed reservoirs, (man- made lakes), to exploit water resources at will. In all natural lakes and reservoirs changes occur in the water quality parameters as it relates to chemical nutrients, temperature and turbidity over time. These changes are collectively referred to as "Reservoir Ageing", of which sedimentation and eutrophication are primary. Reservoir Ageing has consequences which adversely affect and defeat many of the intended uses of the …