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Commonwealth Times 2011-09-12 Sep 2011

Commonwealth Times 2011-09-12

Commonwealth Times, 1969-

No abstract provided.

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Developing A Hybrid Model To Predict Student First Year Retention And Academic Success In Stem Disciplines Using Neural Networks, Ruba Alkhasawneh Jul 2011

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 …

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Novel Methodology For Assessing Phytoplankton Response To Pco2 Enrichment In Fresh And Saltwater, Susan B. Gifford Jul 2011

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 …

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Ecological Profiling Of Bird-Mosquito Interactions In Central Virginia, Anna Riggan Jul 2011

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 …

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Growth Of Age-0 Atlantic Menhaden (Brevoortia Tyrannus) In Two Tidal Freshwater Tributaries Of Chesapeake Bay, Peter M. Sturke Jul 2011

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.

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Microbial Community Function In Freshwater Wetland Soils: Using Extracellular Enzyme Analysis To Study The Effect Of Moisture And Vegetation, Aaron Porter Jun 2011

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 …

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The Superfund Program Past And Present Funding Implications, Nicole Franklin May 2011

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 …

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Cumulative Risks To Eastern Oysters, Crassostrea Virginica In The James River, Va, Vrushali Lele May 2011

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 …

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Phytoremediation Of Pcb Contaminated Soil: Effectiveness And Regulatory Policy, Nathan Pinsker Apr 2011

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 …

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Commonwealth Times 2011-02-21 Feb 2011

Commonwealth Times 2011-02-21

Commonwealth Times, 1969-

No abstract provided.

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Virginia Commonwealth University Commencement Program [2011], Virginia Commonwealth University Jan 2011

Virginia Commonwealth University Commencement Program [2011], Virginia Commonwealth University

VCU Commencement Programs

No abstract provided.

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Virginia Commonwealth University Fall Commencement Program [2011], Virginia Commonwealth University Jan 2011

Virginia Commonwealth University Fall Commencement Program [2011], Virginia Commonwealth University

VCU Commencement Programs

No abstract provided.

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Determining Impediments To Gene Flow In A Natural Population Of Cornus Florida L. Cornaceae, Using Integrative Landscape Genetic Techniques, Crystal Meadows Jan 2011

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.

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Factors Influencing Macroinvertebrate Diversity And Community Composition In Riverine Freshwater Rock Pools, Chtaura Jackson Dec 2010

Factors Influencing Macroinvertebrate Diversity And Community Composition In Riverine Freshwater Rock Pools, Chtaura Jackson

Theses and Dissertations

I examined a system of 378-riverine rock pools situated along the James River in Richmond, Virginia, to uncover the factors influencing their macroinvertebrate diversity and community composition. I characterized (total = 60) the physical characteristics, water quality, hydrology, and community assemblages in July 2009 for a subset of pools. I examined whether selected environmental factors (pH, nearest neighbor distance, depth, surface area and inundation height) were related to macroinvertebrate diversity and community composition. Species richness and total abundance of all taxa increased with pool pH and surface area. Ordination indicates that nearest neighbor distance (NND) and pH varied significantly among …

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Depth And Time Related Variations Of Microbial Communiites In An Emergent Freshwater Wetland, Amy Jenkins Dec 2010

Depth And Time Related Variations Of Microbial Communiites In An Emergent Freshwater Wetland, Amy Jenkins

Theses and Dissertations

Soils, and the microbial communities contained within them, are vital for most chemical, physical, and biological processes. This study investigated how microbial community structure responded to environmental changes, such as hydrology, across vertical space (depth) and time in an emergent fresh water wetland. Research was conducted in a non-tidal freshwater wetland along the James River (Charles City County, Virginia) by establishing plots in two areas that experienced different hydrologic regimes and plant communities. Soil cores (30 cm) were collected monthly from January 2008 to February 2009, and then every two to three months thereafter until October 2009, for a total …

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Phytoremediation Of Copper Contaminated Waste Water Using Lemna Minor, Mark Apelt Nov 2010

Phytoremediation Of Copper Contaminated Waste Water Using Lemna Minor, Mark Apelt

Theses and Dissertations

The use of natural remediation methods to remove contaminants from waste water is becoming more popular. Plants have been used for several decades, yet their use for municipal waste water contaminated by heavy metals is limited to a few studies which focus on the Mercury and Chromium (Bennicelli, et.al, 2004). This study specifically attempted to determine the viability for using Lemna minor to remediate municipally generated wastewater contaminated with copper. The study used 100 ml samples of wastewater, artificially spiked with 8 mg/L of copper sulfate and seeded with approximately 100 Lemna minor fronds. Each treatment was repeated 15 times …

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Commonwealth Times 2010-11-18 Nov 2010

Commonwealth Times 2010-11-18

Commonwealth Times, 1969-

No abstract provided.

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Commonwealth Times 2010-05-03 May 2010

Commonwealth Times 2010-05-03

Commonwealth Times, 1969-

No abstract provided.

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Spatial And Temporal Distribution Of Larval Fishes In A Large Tidal River., Harold Seelig Apr 2010

Spatial And Temporal Distribution Of Larval Fishes In A Large Tidal River., Harold Seelig

Theses and Dissertations

There are few published studies of larval fish assemblages from unregulated, tidal freshwater rivers. Patterns in the spatial and temporal distribution of larval fishes in the Mattaponi River were examined. Sampling took place on a weekly basis from February through August, 2006 and 2007. Larval fishes were categorized by taxa, reproductive guild, and residency guild. Group comparisons using multi-response permutation procedures (MRPP) indicated significant spatial and temporal differences in assemblage composition on multiple scales. Differences in assemblage composition were analyzed using non-metric multidimensional scaling (NMS). Interannual differences were attributable to anadromous and semi-migratory species. Seasonal differences were attributable to herrings, …

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Patterns In Fish Community Structure In A Regulated River, Richard Davis Apr 2010

Patterns In Fish Community Structure In A Regulated River, Richard Davis

Theses and Dissertations

I examined the abundance, composition, and distribution of fish communities in the lower Roanoke River, a hydropeaking system in North Carolina. Fishes were sampled at before and after peaking events over three years; 2007 to 2009. I evaluated trends in species richness, diversity, and assemblage composition. There were no significant differences in either richness or diversity suggesting consistent trends in richness and diversity throughout the study. I used non-metric multidimensional scaling (NMDS) to create a community composition model. Fish composition was noticeably greater post-peaking and changed minimally across time and event. There were no statistically significant differences in species composition …

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Shafer Court Connections (2010-03) Mar 2010

Shafer Court Connections (2010-03)

Shafer Court Connections, 1994-2010

For alumni of the Academic Campus of Virginia Commonwealth University.

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Virginia Commonwealth University Commencement Program [2010], Virginia Commonwealth University Jan 2010

Virginia Commonwealth University Commencement Program [2010], Virginia Commonwealth University

VCU Commencement Programs

No abstract provided.

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Virginia Commonwealth University Fall Commencement Program [2010], Virginia Commonwealth University Jan 2010

Virginia Commonwealth University Fall Commencement Program [2010], Virginia Commonwealth University

VCU Commencement Programs

No abstract provided.

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A Web Of Influence: How The Msp Program Has Shaped The Thoughts Of Three Instructors, J. Reyes Jan 2010

A Web Of Influence: How The Msp Program Has Shaped The Thoughts Of Three Instructors, J. Reyes

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

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Zooplankton Abundance, Community Composition And Grazing In The James River Estuary (Virginia, Usa), Laura E. Barry Dec 2009

Zooplankton Abundance, Community Composition And Grazing In The James River Estuary (Virginia, Usa), Laura E. Barry

Theses and Dissertations

This study examined the extent to which zooplankton in the James River Estuary (Virginia, USA) exploit the available algal-food resources. Zooplankton abundance, community composition and grazing rates were assessed at three locations which included a site with high algal production (near the VCU Rice Center) and two sites where algal production was lower. Grazing rates were measured by determining the rate of phytoplankton decline (as chlorophyll a) during 48-hour incubation experiments in the presence and absence of zooplankton. Significant differences in zooplankton abundance were observed among the three sites, with the greatest average zooplankton density (434 ± 69 ind/L) occurring …

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Commonwealth Times 2009-11-23 Nov 2009

Commonwealth Times 2009-11-23

Commonwealth Times, 1969-

No abstract provided.

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Commonwealth Times 2009-11-09 Nov 2009

Commonwealth Times 2009-11-09

Commonwealth Times, 1969-

No abstract provided.

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Commonwealth Times 2009-09-24 Sep 2009

Commonwealth Times 2009-09-24

Commonwealth Times, 1969-

No abstract provided.

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Factors Limiting Benthic Algal Abundance In Virginia Streams Of The Coastal Plain, Michael Brandt Jul 2009

Factors Limiting Benthic Algal Abundance In Virginia Streams Of The Coastal Plain, Michael Brandt

Theses and Dissertations

Algae are important components of stream food webs and often used in biomonitoring assessments. Little is known regarding the factors that limit their abundance in streams of the VA Coastal Plain. The surficial geology of the Coastal Plain is predominately sandy deposits which comprise the dominant substrate in streams of this region. In a comparative study of five streams located near the VCU Rice Center, we quantified substrate composition, light availability, and nutrient concentrations to assess their relative importance in determining benthic algal abundance. The proportion of stream area comprised of hard substrates was a significant predictor of variation in …

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An Evaluation Of Bacterial And Fungal Contributions To Organic Matter Decomposition Along A Soil Moisture Gradient, Morgan Rawls Jul 2009

An Evaluation Of Bacterial And Fungal Contributions To Organic Matter Decomposition Along A Soil Moisture Gradient, Morgan Rawls

Theses and Dissertations

The decomposition of plant litter is a critical biological function that aids in nutrient cycling and energy transfers within and between ecosystems. The primary decomposers of dead leaf material are bacteria and fungi, though there is no consensus as to which of these groups is dominant, nor is it known how the abundance and composition of these communities changes over time. The objectives of this study were to examine the relative contributions of bacterial and fungal populations to leaf organic matter (OM) decomposition and to consider the effect of moisture availability on the microbial community. The study was conducted across …

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