Digital Commons Network^™

Using Macroinvertebrate Community Composition To Distinguish Between Natural And Anthropogenic Sedimentation, Amanda E. Schutt

Theses and Dissertations

Excess fine sediment from human activity is a major pollutant to streams across the U.S.; however, distinguishing human-induced sedimentation from natural fine sediment is complex. The U.S. Environmental Protection Agency recently implemented a protocol for the quantitative field assessment of human-induced sedimentation using measurements of stream geomorphology. Macroinvertebrate community composition, streambed sediment stability, and sediment composition were studied at 49 sites in the James River watershed in central Virginia. Sediment composition was found to be a stronger driver of community composition than sediment stability. Although I was not able to show that macroinvertebrate metrics were related to sediment stability independently …

Characterization Of Microsatellite Loci And Pilot Population Genetic Analysis In Hickory Shad, Alosa Mediocris, Fnu Vishakha

Theses and Dissertations

The hickory shad (Alosa mediocris) is a relatively understudied species of the anadromous fish sub-family Alosinae. This study, the first population genetic analysis of this species, employed 12 neutral microsatellite loci to estimate genetic diversity and population structure in tributaries of lower Chesapeake Bay, Virginia including James River and its tributaries (Appomattox and Chickahominy Rivers), Rappahannock River, and Pamunkey River. Genetic variation was extremely low. Estimates of observed heterozygosity were lower than expected heterozygosity. Significant population structure was detected among the six samples (FST = 0.093, p = 0.01). Effective population sizes were low (Ne ranged from 2 to 134). …

Economic Evaluation Of Biofuel Production Through Bio-Gasification Power Facility Using Modeling Method, Yangyang Deng

Theses and Dissertations

Since bio-gasification is a potentially more efficient way to utilize bio-energy, the economic feasibility becomes one of the greatest issues when we apply this new technology. Evaluation of economic feasibility of a bio-gasification facility needs understanding of its production unit cost under different capacities and different working shift modes. The objectives of this study were to evaluate the unit cost of bio-syngas and biouel products at different capacities by using economic modeling method. Result showed that economic feasibility of a power facility was significantly affected by its production capacity and operating mode (one shift, two shifts, or three shifts mode). …

The Perceived Degree Satisfaction And Job Preparedness Of On-Campus And Distance Campus Graduates From The Bachelor Of Science In Interdisciplinary Studies Degree Program At Mississippi State University, Michael K. Busby

Theses and Dissertations

Research suggests that perceived degree satisfaction and perceived job preparedness are related to positive experiences from undergraduate degree programs. Research also suggests that perceived levels of degree satisfaction and job preparedness may vary based on whether the student was a traditional or nontraditional student. Therefore the purpose of this study was to analyze the level of degree satisfaction and the level of job preparedness of distance learning students enrolled in the Bachelor of Science in Interdisciplinary Studies program at Mississippi State University in relation to that of on-campus students enrolled in the Bachelor of Science in Interdisciplinary Studies program at …

A Confidence-Prioritization Approach To Data Processing In Noisy Data Sets And Resulting Estimation Models For Predicting Streamflow Diel Signals In The Pacific Northwest, Nathaniel Lee Gustafson

Theses and Dissertations

Streams in small watersheds are often known to exhibit diel fluctuations, in which streamflow oscillates on a 24-hour cycle. Streamflow diel fluctuations, which we investigate in this study, are an informative indicator of environmental processes. However, in Environmental Data sets, as well as many others, there is a range of noise associated with individual data points. Some points are extracted under relatively clear and defined conditions, while others may include a range of known or unknown confounding factors, which may decrease those points' validity. These points may or may not remain useful for training, depending on how much uncertainty they …

A Water Quality Investigation Of Kimages Creek, Michael Trop

Theses and Dissertations

Analysis of continuous monitoring water quality data (temperature, specific conductivity, depth, pH, dissolved oxygen, and turbidity) at two locations in a tidal freshwater creek (Kimages Creek) characterized seasonal variation and responses to short-term events. Supplemental water quality measurements were collected to describe longitudinal variations in the creek. There were significant differences in water quality between the two continuous monitoring stations (one tidal and unforested, the other non-tidal and forested) over varying time scales. Rain events showed increases in turbidity, depth and dissolved oxygen, and reductions in temperature, conductivity, and pH at both stations. Tides influenced the water quality at the …

Essential Spawning Habitat For Atlantic Sturgeon In The James River, Virginia., Geoffrey Austin

Theses and Dissertations

Substrate composition plays a critical role in determining the spawning success of Atlantic sturgeon. A benthic analysis of the tidal freshwater portion of the James River, Virginia, was performed to locate and protect remaining sturgeon spawning habitat within the James River system. I modeled structural habitat, substrate distribution, and river bathymetry from Richmond, Virginia to the Appomattox River confluence. A classification model was developed to describe the dominant substrate type (mud/silt, sand, gravel, bedrock) using side scan sonar data collected from August 2011-Febuary 2012. River depth, bottom imagery, substrate density (hardness), and ground truth substrate samples were interpolated into a …

Analysis Of The Fish Community On Tidal-Freshwater Constructed Reefs, Briana Langford

Theses and Dissertations

Constructed reefs are used successfully in marine systems to enhance spawning habitat; this study examines the effectiveness of constructed reefs in a tidal-freshwater river. Fish abundance, species diversity and richness, residency, water column position, reproductive guilds, and feeding guilds were analyzed on two constructed reefs in the tidal-freshwater James River and compared to silted regions representing the primary substrate in the river. Reefs were sampled using hydroacoustics, electroshocking, gillnetting, trawling, and egg mats. The constructed reefs had a greater proportion of fish that broadcast spawn over hard substrate and a trend of more overall individual, residential, and demersal fish. The …

Exploring The Biodiversity Of Anammox In Atlantis Ii And Kebrit Brine Pools' Interfaces, Ibrahim Farag

Theses and Dissertations

The Red Sea brine pools are unique environments to assess the biochemical adaptation of marine bacteria. The role of nitrogen in marine biogeochemistry is central and greatly influences the diverse elements including carbon and phosphorus. Anammox communities play a significant role in the total nitrogen loss especially in deep sea and deep ocean ecosystems. Despite this, the biodiversity of Anammox bacteria have not been previously investigated in any brine pool ecosystems. With the advances of the metagenomics based approaches, the exploration of the yet uncultured microbial communities including the Anammox bacteria has taken different perspectives. Anammox communities are currently analyzed …

Spatial Patterns Of Herbaceous And Woody Recruitment In A Recently Restored Mixed Tidal Regime Freshwater Wetland, James B. Deemy

Theses and Dissertations

Ecological restoration of a converted wetland was characterized within a recently drained impoundment along the James River in Charles City County, Virginia. Colonizing vegetation was assessed over three growing seasons in both tidal and non-tidal environments. Study objectives were to (1) examine geospatial relations of recruitment patterns among colonizing species over three growing seasons, (2) quantify species composition and potential differences between extant species cover and soil seed banks across restored and natural wetland habitats and (3) assess geospatial patterns to develop a GIS model of bald cypress (Taxodium distichum L.) recruitment. The two most common native colonizing species during …

Determining An Optimum Cropping Pattern For Egypt, Loujaina M. El Sayed

Theses and Dissertations

Agriculture is considered to be the major economic activity in Egypt despite the government policies that favored other sectors since the second half of the 20^th century. However, Egypt currently faces a food security challenge that stems from the increasing demand for food in light of huge population growth and the inability of the agricultural sector to fulfill the abovementioned increasing demand.

This research focuses on the vertical expansion of the agricultural sector through attempting to determine the optimum cropping mix for Egypt in the year 2017. A fuzzy goal programming (FGP) approach for optimal land allocation is utilized. …

Sources And Fates Of Nutrients In The Tidal, Freshwater James River, William Isenberg

Theses and Dissertations

Tidal freshwater reaches of estuaries may play an important role in mitigating nutrient fluxes from watersheds to the coastal zone due to their location at the interface between riverine and estuarine systems. We developed annual N and P budgets for the tidal, freshwater James River over 4 calendar years (2007-2010) taking into account riverine inputs at the Fall Line, local points sources (including CSO events), ungagued inputs, riverine outputs, and tidal exchange. The tidal freshwater James River experiences high areal loading rates of TN (383 mg/m2/d) and TP (70 mg/m2/d) due to the combined effects of large watershed area and …

The Effect Of Multiple Interventions On Environmental Attitudes And Behaviors, Jeremy P. Kinne

Theses and Dissertations

New federal mandates require federal entities to reduce resource usage across the board. Additionally, commercial enterprises are evaluating methods of reducing resource consumption to reduce costs and become more ecologically friendly. In response, researchers have begun to evaluate the intentions and behaviors of individuals to determine how to encourage individual participation in reduction methods. This study used a quasi-experimental design of non-equivalent groups to evaluate the effects of Computer Based Training and persuasive speech on individual environmental attitudes and behavior. Using the Theory of Planned Behavior model to determine intentions and behaviors, this study utilized surveys to evaluate the relative …

Macrobotanical Evidence Of Diet And Plant Use At Wolf Village (42ut273), Utah Valley, Utah., Wendy Dahle

Theses and Dissertations

Farming played a role in the subsistence base for the Fremont culture, but there is no consensus as to how significant that role was. Maize is consistently found in Fremont sites, but evidence of wild plant use is also abundant. The use of both domesticates and foraged plants by the Fremont, combined with the diversity of the landscape and sites that were inhabited by the Fremont, contributes to the diversity of theories on Fremont subsistence. This thesis examines evidence for plant usage at Wolf Village, a Fremont site in Utah Valley. Wolf Village is ideally situated for a Fremont farming …

Evaluation Of Brook Trout (Salvelinus Fontinalis) Introductions And Re-Introductions Into Four Virginia Blue Ridge Mountain Streams, Michael Isel Iii

Theses and Dissertations

Approximately 100 brook trout were transplanted into each of four Virginia streams in September 2008. Garth Run and Kinsey Run were re-introductions, and Wildcat Hollow and Sweet Run were new introductions. Single pass electrofishing (EF) surveys were conducted with a backpack electrofisher five times during the study. Selected trout > 70 mm but < 100 mm and all trout > 100 mm received a Biomark® 134.2 kHz passive integrated transponder (PIT) tag to identify individual fish upon recapture. Trout were present in all streams almost three years post introductions. Catches decreased across the first four surveys. Young of year catch rates severely decreased from June 2009 (n = …

Composition Of Suspended And Benthic Particulate Matter In The Tidal Freshwater James River, Anne Schlegel

Theses and Dissertations

Investigating linkages between the compositions of suspended (seston) and benthic particulate matter is important to the understanding of organic matter (OM) cycling and nutrient retention in aquatic systems. We compared the quantity and quality of the truly suspended (TS) and settleable (SB) fractions of seston as well as benthic particulate matter in the tidal freshwater James River, Virginia. The mass of seston and OM was consistently higher in the TS fraction compared to the SB fraction. OM was preferentially retained in the TS fraction relative to seston. The proportional contribution of OM constituents (chlorophyll a, particulate organic carbon and nitrogen) …

Factors Predicting Exercise Behavior Of Graduate Students, Bibha Gautam

Theses and Dissertations

Graduate school is often experienced as a time of increased demands/expectations resulting in heightened levels of stress due to academic work, family responsibilities, job demands, financial pressure, and other life related issues. Besides stress, graduate school also brings about significant physical inactivity due to the shift of the immediate priority to academic accomplishment. Reports of increasing prevalence of cardiovascular disease (CVD) risk factors among students highlight that this group may have particular risk not well-identified. Yet, relative risk can be reduced by lifestyle modifications, such as eating well, exercising, and stress reduction. The majority of the risk factors, to a …

Developing A Hybrid Model To Predict Student First Year Retention And Academic Success In Stem Disciplines Using Neural Networks, Ruba Alkhasawneh

Theses and Dissertations

Understanding the reasoning behind the low enrollment and retention rates of Underrepresented Minority (URM) students (African Americans, Hispanic Americans, and Native Americans) in the disciplines of science, technology, engineering, and mathematics (STEM) has concerned many researchers for decades. Numerous studies have used traditional statistical methods to identify factors that affect and predict student retention. Recently, researchers have relied on using data mining techniques for modeling student retention in higher education [1]. This research has used neural networks for performance modeling in order to obtain an adequate understanding of factors related to first year academic success and retention of URM at …

Novel Methodology For Assessing Phytoplankton Response To Pco2 Enrichment In Fresh And Saltwater, Susan B. Gifford

Theses and Dissertations

Atmospheric CO2 emissions are on the rise and are expected to reach 780 parts per million by the year 2100. Research investigating the impacts of increasing CO2 is a relatively new field and the response of phytoplankton communities is largely unknown, especially in coastal and freshwater ecosystems where no CO2 manipulation studies have completed. The present study attempts to encourage uniformity in methods utilized in CO2 perturbation studies and identifies changes in phytoplankton abundance in freshwater (James River) and coastal ocean (Atlantic, Cape Hatteras) sites. A novel bubbling method to manipulate pCO2 was compared with the classic method of acid …

Ecological Profiling Of Bird-Mosquito Interactions In Central Virginia, Anna Riggan

Theses and Dissertations

Current methods of mosquito surveillance estimate general population abundances, but fail to represent the relationship of vector abundance to host density important to determining transmission risk of mosquito-borne pathogens (MBP). We sought to address this limitation by creating a novel mosquito trap that directly sampled mosquitoes seeking to feed on nesting birds. The primary objectives of this study were to (1) assess the efficiency of the Nest Mosquito Trap (NMT) and how this is affected by nest box size. (2) assess whether the NMT affects bird, specifically nest success in Prothonotary Warblers (Protonotaria citrea), and adult behavior. (3) compare our …

Growth Of Age-0 Atlantic Menhaden (Brevoortia Tyrannus) In Two Tidal Freshwater Tributaries Of Chesapeake Bay, Peter M. Sturke

Theses and Dissertations

Few studies have described growth rates of age-0 Atlantic menhaden (Brevoortia tyrannus). Growth rates from tidal freshwater habitats of the Mattaponi and James Rivers, Virginia in 2009 were described and compared using otolith microstructural analyses. Larval tidal freshwater growth rates were significantly faster in the culturally eutrophic James River when compared to those collected from the Mattaponi River (p-value < 0.001). Elevated primary production within tidal freshwater habitats promotes favorable conditions for larval Atlantic menhaden growth. No differences between river habitats for juvenile growth rates were evident. Comparisons of age-0 growth rates to higher salinity habitats indicate that tidal freshwater habitats should be considered essential habitat for age-0 Atlantic menhaden.

Microbial Community Function In Freshwater Wetland Soils: Using Extracellular Enzyme Analysis To Study The Effect Of Moisture And Vegetation, Aaron Porter

Theses and Dissertations

Differences in microbial function via extracellular enzyme activity (EEA) were investigated to determine the potential effects of hydrology and plant-soil-microbe interactions in a young non-tidal freshwater riparian wetland. To study these relationships, three plots were established along a moisture gradient (Wet, Intermediate, Dry) within VCU Rice Center Within each main plot, five subplots were left undisturbed while another five were cleared of all above-ground plant biomass. Homogenized soil cores (top 10 cm) were analyzed for pH, redox, C:N, soil organic matter (SOM) content, saturation, and temperature. Microbial function was assessed using extracellular enzyme analysis. For most enzymes, a site difference …

Investigating The Influence Of Computer Programs On Perception And Application Of Mathematical Skills, Neil M. Bly

Theses and Dissertations

Existing research suggests an intuitive relationship between mathematics and computer programming. These previous studies have focused primarily on the cognitive connection and have ignored the potential impact of programming on an individual's perception and application of mathematical skills. By surveying and interviewing a variety of participants, this study aims to provide a descriptive foundation for the experiential side of cognitive correlations and causalities. These phenomenological accounts, garnered from individual interviews of seven different programmers, indicate four specific areas of interest. First, learning to program provided context for many abstract concepts. Second, programming illustrated the important distinction between understanding the application …

The Superfund Program Past And Present Funding Implications, Nicole Franklin

Theses and Dissertations

The present research examines the impact of not reauthorizing the Superfund taxes on the operations of the program. EPA NPL site status data were obtained from the EPA CERCLIS database for analysis in this study. Data were selected for the fiscal years 1981 to 2009 in four NPL listing status categories: proposal to the NPL, final NPL listing, deletion from the NPL, and achievement of construction completion. Since the Superfund tax expired in 1995, data from the 1981 to 1995 fiscal years and data from the 1996 to 2009 fiscal years were analyzed to determine if there were mean differences …

Cumulative Risks To Eastern Oysters, Crassostrea Virginica In The James River, Va, Vrushali Lele

Theses and Dissertations

In an effort to apply Cumulative Risk Assessment (CRA) as developed by the U.S. EPA, the present study investigates the cumulative risks to Eastern oysters due to multiple stressors such as salinity, temperature and oxygen and carbon dioxide. I also compared the effectiveness of the Hazard Quotient Method (HQ) in CRA. Ambient conditions in the James River, VA were obtained from the Virginia DEQ database and respiratory responses were estimated using values from the literature. The multiple environmental stresses are evaluated using a probabilistic analysis that combines the environmental conditions. It was concluded that salinity was the most influential stressor …

Developing A Remote Sensing Algorithm For Deriving Soil Moisture From Spectral Reflectance, Santosh Rijal

Theses and Dissertations

Wet weather cycle since 1993 has brought ground water level closer to the surface of the soil in many areas in the Red River Valley (RRV) of the North basin. Many farmers have to delay spring plantation or autumn harvest due to excessive moisture in', their farmland. In such case, it becomes increasingly important to have timely and accurate information on the soil moisture conditions. Conventional soil moisture measurement techniques are point-based that results in poor spatial representation of soil moisture. Remote sensing techniques offer many potential advantages over traditional means such as repetitive coverage and areal representation. The objective …

Phytoremediation Of Pcb Contaminated Soil: Effectiveness And Regulatory Policy, Nathan Pinsker

Theses and Dissertations

The purpose of this paper was to combine available peer-reviewed literature on PCB phytoremediation and make direct comparisons using ANCOVA statistics in order to determine if and what plants are presently a viable option for the remediation of PCB contaminated soils. Pumpkin (Curbita pepo cv Howden) consistently had the top root and shoot concentrations, as well as total plant accumulation. Their consistency shows that they can be reliable in the field and the most viable option. Tall fescue and sedge were also top contenders. Due to the small sample size for many plants and accounting for several confounding variables, very …

Interdisciplinary Authentic Assessment: Cognitive Expectations And Student Performance, Jenni M. Taylor

Theses and Dissertations

This two-pronged quantitative, non-experimental design study, conducted at an urban secondary school of 472 students in Los Angeles, California, was designed to gain understanding of the potential impact of interdisciplinary authentic assessment and the manner and complexity with which such tasks push students to think. Since limited research has been conducted around the results of such practices at the secondary school level, this research serves as a pilot study to examine (a) cognitive levels of Bloom's Taxonomy present within four interdisciplinary authentic assessment tasks, following an ongoing professional development intervention and (b) student performance on these assessments of varying cognitive …

Satisficing: A Decision-Making Strategy For School Choice, Kristine Anne Thompson

Theses and Dissertations

The purpose of this study was to investigate parent decision-making regarding school choice. Data were collected through a survey on how parents approached the decision making task of choosing a school for their child. Parents of kindergarten and first grade students in one public school district in Minnesota and five private schools in surrounding communities were invited to participate.

Four bodies of literature provide the theoretical basis of the study. They are education reform; school choice in Minnesota; factors parents consider when choosing schools; and decision-making theory.

Satisficing, a concept drawn from Herbert Simon's (1955, 1956) theory of bounded rationality …

Determining Impediments To Gene Flow In A Natural Population Of Cornus Florida L. Cornaceae, Using Integrative Landscape Genetic Techniques, Crystal Meadows

Theses and Dissertations

This study examined the impact intervening environment has on gene flow in the insect pollinated understory tree, Cornus florida L., by combining GIS and landscape genetic techniques (Least Cost Path Analysis, Circuit Theory, and Conditional Genetic Distance). Traditional population genetic analysis indicated pair-wise relatedness was significantly correlated to distance (Pearson; r = -0.312, P < 0.001) suggesting a spatial component to offspring relatedness. Dispersal throughout the study site was non-random, exhibiting a high degree of pollen pool structure due to restricted gene flow (Two-Generation Analysis; Φft = 0.161, P = 0.001). Forest structure was quantified in GIS layers representing coniferous canopies, mixed hardwood canopies, C. florida canopies, open understory (roads), and open understory/canopy due to tree removal. Of these layers, landscape isolation for the roads layer provided the best-fit model for describing genetic differentiation among sampled pollen pools (Mantel; r = 0.542, P = 0.001). These data also suggest that improved biological inferences can be gained by examining a range of landscape isolation models.