The 16th Annual

NC State University
Undergraduate Research Symposium

 

Abstracts

 

 

Physical & Mathematical Sciences

Abstracts

Abstracts are listed in alphabetical order by the last name of the corresponding author.

 

 


 

 

  • Biological Sciences abstracts

Applied Sciences (Crop, Poultry, Animal, and Horticultural Sciences)

Ecology, Environmental, Conservation, Botanical
Molecular, Biochemical, Genetics, Cell Biology
Zoology, Physiology, Behavior, Neurobiology

 

 

 

 

 


 

 

Student Author(s): 

Anderson, Trevor E.

Department(s):

Physics

Research Mentor(s)

Keith Weninger/Physics

Title of Presentation:

Pure SNARE Proteins for a Complex-Study

 

 

A family of proteins known as SNARE’s catalyzes many biological events that involve membrane fusion. Specific interactions among SNARE proteins influence whether or not two membranes will merge. A deeper understanding of many biological events will result from greater knowledge of both how the proteins interact with each other, and also how foreign molecules such as toxins can influence or prevent the whole process. I have spent the last semester expressing and purifying SNARE proteins to produce high-purity, concentrated samples for biochemical studies. I have used these samples to determine the ability of unrelated families of SNARE’s to assemble into stable complexes.

 


 

 

Student Author(s): 

Atakturk, Burcu A.

Department(s):

Accounting

Research Mentor(s)

Al Chen/Accounting

Title of Presentation:

Evaluating Alternative Strategic Cost Management Approaches

 

 

This research project analyzes different costing systems in use and planned to be used in business settings and identify strengths and weaknesses of each system analyzed. The costing systems considered include activity-based costing (ABC), Theory of Constraints (TOC) and Resource Consumption Accounting (RCA). A distinction is also drawn between traditional cost analysis and strategic cost analysis. Questions addressed include: What is strategic cost management? What different perspectives on cost exist? And finally, what is the strategic cost management process? One of the fundamental ventures of any business is to make a profit. Good cost management within a business is vital to making profit. There are multiple costing systems in use today and it is essential to know which is the best for the current venture. ABC and TOC are two of the most popular costing systems in use today. RCA, on the other hand, is a relatively new system about which little is known. It is important to know the difference between these three systems and how best to utilize each of them, both individually and in combination with other methods.

 


 

 

Student Author(s): 

Attarian, Adam

Department(s):

Mathematics

Research Mentor(s)

Hien T. Tran/Mathematics

Title of Presentation:

A Hybrid Optimization Approach for the Optimal Design of Traveling Wave Tubes

 

 

Traveling wave tubes are common devices with widespread use in both satellite and terrestial comunications as well as areas such as electronic counter measures. We present a hybrid optimization approach for the optimal design of the electron based device based on two independent physics-based design and simulation codes. In particular, we use the CHRISTINE suite of large signal codes to model the slow wave circuit, in conjunction with Beam Optics Analysis to model a multi-stage depressed collector. These two simulation codes will be combined in a hybrid framework to automate the process of optimizing several physical parameters while realizing several design constraints. The equations describing the device properties as well as the objective functions will be discussed, and examples of optimized TWTs will be presented.

 


 

 

Student Author(s): 

Blackmer, Amanda C.

Kelley, Richard L.

Department(s):

Chemistry

Research Mentor(s)

Stefan Franzen/Chemistry

Title of Presentation:

In vitro Assembly of Synthetically Produced Viral RNA Transcripts

 

 

Red Clover necrotic mosaic virus (RCNMV) provides an ideal platform to develop a multifunctional particle with specific application to therapeutic and gene delivery in humans. In vitro assembly is a controlled method to propagate engineered virus-like particles in high yield with greater purity than those obtained by plant propagation. The assembly of the RCNMV capsids is dependent on the presence of viral RNA. To obtain the RNA for in vitro assembly, we performed transcriptions of viral RNAs cloned into PUC expression vectors. These transcript products were characterized using UV/VIS and agarose gel electrophoresis. The purified capsid proteins were obtained from disassembled wild type RCNMV. The purity of the protein was confirmed by UV/VIS and SDS/Page gel electrophoresis. The in vitro assembly was accomplished by mixing the protein and RNA in a dialysis cassette at pH 10 and then reducing the pH to 5.5 overnight. Dynamic Light Scattering (DLS) and Transmission Electron Microscopy imaging (TEM) were done to confirm the formation of particles. Further experiments will be conducted to access the in vivo infectivity of the virus-like particles.

 


 

 

Student Author(s): 

Brewer, Jason P.

Johnson, Matthew S.

Thelen, Michael Y.

Department(s):

Marine and Atmospheric Sciences

Statistics

Research Mentor(s)

William F. Hunt Jr./ Statistics

Title of Presentation:

Protecting Human Health: Modeling the Prevalence of Fine Particulate Matter in Air Quality Index Reporting

 

 

Fine particulate matter is a significant pollutant that endangers human health. Small particulates, 2.5 micrometers in diameter or less, penetrate further into the lungs of humans than larger particulates leading to increased cases of respiratory diseases and eventual death. Both annual mean and 24 hour National Ambient Air Quality Standards have been set for fine particulate matter (PM2.5). PM2.5 is one of five pollutants reported in the USEPA’s Air Quality Index. It is critically important that today’s PM2.5 value can be accurately forecasted so it can be reported to the public with an appropriate health advisory. Our objective is to develop reliable forcasting regression models to serve as tools for predicting PM2.5. The regression models will take into account various meteorological parameters such as temperature, wind speed, wind direction, and yesterday’s PM2.5 measurements. Our client, Maryland Department of Environment, provided all meteorological and particulate matter data. Analyses of selected particulate matter monitoring stations and meteorological sites in the state of Maryland have lead to discoveries of certain PM2.5 patterns. Trends show PM2.5 variations between winter and summer seasons as well as weekday and weekend periods. Various patterns, interaction terms, nonlinear curvature, and other possible confounders will be taken into account. Regression analysis and model building techniques will be implemented for prognostic purposes and also for interests in inferential procedures on linear combinations of regression variables. Development of more specific regression models and software packages for these different periods will improve future forecasts of PM2.5 in addition to making the information readily accessible to the public.

 


 

 

Student Author(s): 

Burleyson, Casey D.

Bryant, M. Tai

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s)

Sandra Yuter/Marine, Earth and Atmospheric Sciences

Title of Presentation:

Observation and Analysis of 19 Winter Storm Events In the North Carolina Mountains

 

 

The purpose of this research is to obtain and analyze observations of the physical characteristics of precipitation during snow events in the southern Appalachians. On average, this region receives 125 cm of snowfall per year. We assembled a meteorological tower on Poga Mountain, located on the western slopes of the Appalachians at an elevation of 1137 m, to measure temperature, pressure, humidity, wind speed, wind direction, and soil moisture. Collocated with the instrument tower is a vertically pointing Ku-band radar to observe the vertical profile of storms as they pass overhead. Additional measurements are made of particle size distributions, snow depth at the surface and snow liquid water equivalent. During the 2006-2007 snow season there have been 19 snowfall events at the site with accumulations ranging from 0.25 cm to 14.7 cm. Twelve of the 19 snow events occurred when the wind was out of the northwest and flowing up the mountain slopes. The three heaviest snow events (10.2 cm, 13.9 cm, 14.7 cm) occurred when Canadian air masses pushed southeastward into the Appalachian range. Ratios of snow liquid water equivalent to snow depth ranged from 0.0125 to 0.5 with most values < 0.1. The majority of storm top heights for the observed snow events were less than 2 km above ground level, much shallower than previously thought. Results from the analysis will be used to improve understanding of the physics of snow and to better forecast snow events.

 


 

 

Student Author(s): 

Carroll, Turhan K.

Department(s):

Applied Mathematics

Research Mentor(s)

Hien T. Tran/Mathematics

Title of Presentation:

Acoustic Pressure Waves in a Pipe

 

Sound is a part of our everyday experience. As a sound wave travels through a medium, it either reaches the end of the medium or enters another medium through which it could travel. The interface of the two media is referred to as the boundary. Understanding sound pressure waves and corresponding boundary conditions is important for the proper operation of many musical instruments and for the design of, for example, concert halls and auditoriums. In this project, acoustic pressure waves in a PVC pipe were studied using three types of physical boundary conditions: a hard plate, a soft foam sponge, and no boundary. A different mathematical model was used to model each of the boundary conditions. Acoustic data in a PVC pipe is being used to validate the proposed mathematical models for the boundary conditions.

 


 

 

Student Author(s): 

Christoph, Elizabeth E.

Hornsby, Fawn E.

Department(s):

Statistics

Statistics and Applied Math

Research Mentor(s)

William F. Hunt Jr./Statistics

Title of Presentation:

Toxic Overload: Modeling Ambient Mercury Air Pollution at a Trillionth of a Gram

 

 

Mercury is a toxic pollutant that can cause adverse health effects in humans through bioaccumulation in fish. It is released into the atmosphere in several ways, most of which involve industrial processes. The primary health effect of mercury is impaired neurological development. Impacts on cognitive thinking, attention, memory, communication, and fine motor skills have been seen in children exposed to mercury in the womb. Other effects of elevated blood mercury levels include impaired vision, lack of coordination, impaired speech, tremors, insomnia, muscle weakness, and even death. From the atmosphere, mercury enters the water via wet and dry deposition where it bio-accumulates in fish. Because of this concern, mercury air monitoring sites were established in Elizabeth and New Brunswick, NJ. The New Jersey Department of Environmental Protection used the Tekran Continuous Mercury Analyzer to measure elemental, particulate and reactive gas mercury during 2004 and 2005. Using this data, we are constructing a statistical model for our client that will predict mercury as a function of meteorological variables. Using Statistical Analysis Software (SAS) to analyze the data, the mercury concentrations were first broken into diurnal patterns and a lognormal relationship was found in the three phases of mercury: elemental mercury, particulate mercury and reactive gas mercury (RGM), even though the data is measured in a billionth or a trillionth of a gram. We examined weekly, daily, and hourly patterns in the data and compared the three forms of mercury data with meteorological variables to look for other possible patterns in the data. We observed a correlation between wind speed, wind direction and mercury concentrations. Initial scatter plots revealed a cyclical pattern in the data when viewed over time and from wind direction. We developed several models to predict mercury concentrations, and compared them to the current model used by decision makers.

 

 


 

 

Student Author(s): 

Diaz, Michael L.

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s)

Ryan Boyles/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

Quality Control of Meteorological Data

 

 

Accurate meteorological data are important in many applications. However, the automated sensors which measure and record these data occasionally provide inaccurate measurements. Therefore, in order for these data to be useful, a “quality control” system to automatically identify potential errors within large quantities of data is essential. The goal of this project is to augment the climatological range check quality control system of the State Climate Office of North Carolina with another technique which attempts to locate erroneous data by examining the spatial and temporal continuity of each recorded meteorological variable. For each sensor, information from surrounding sensors is used to estimate the value of each variable and its temporal rate of change using spatial interpolation techniques. These calculated values are then compared to the measured values to determine the likelihood that the measurements at a given sensor are accurate. Specific policies to determine this likelihood must be fine-tuned such as to minimize the number of “good” observations which fail the quality control and the number of “bad” observations which pass it. Results indicate that a combination of techniques using the difference between measured and interpolated values, the number of standard deviations between the measured and interpolated values, and the difference between measured and estimated rate of change separate data by their likelihood of failure better than any single technique. However, this quality control system has difficulty accounting for localized effects of high elevation and proximity to the coast. Difficulties also exist near the boundaries of the sensors’s spatial domain, where spatial interpolation produces a strong bias toward the region in the domain’s interior. Despite its shortcomings, this quality control system will greatly improve quality control for the State Climate Office, especially when used in conjunction with the already existing methods.

 

 


 

 

Student Author(s): 

Dixon, Anthony R.

Department(s):

Mathematics

Research Mentor(s)

Hien T. Tran/Mathematics

Mette Olufsen/Mathematics

Title of Presentation:

Mathematical Modeling of Cerebral Blood Flow Dynamics

 

 

Postural change is a common noninvasive procedure used to study short-term regulation of the cardio-respiratory systems including cerebral autoregulation, autonomic and respiratory regulation. In subjects who suffer from orthostatic intolerance, postural change is not well understood, and this work aims to validate a mathematical model that can help describe this regulatory mechanism in more detail. Using a three-element windkessel model, our primary goal is to model the cerebral blood flow during a postural change. Finally, simulation results will be presented depicting how well the mathematical model fit experimental data.

 


 

 

Student Author(s): 

Drukenbrod, Joshua

Harness, Chad

Department(s):

Statistics

Research Mentor(s)

William F. Hunt Jr./Environmental Statistics

Title of Presentation:

Can Analysis of Public Data Bases Help Us Better Understand the Reasons for Elevated Blood Lead Levels in Children?

 

 

Within the past thirty years, there has been a vast reduction in the concentration of lead found in our air, water, soil and homes; however, toxic concentrations still exist and continue to affect our health. Is there something researchers missed in the process? The removal of lead from both lead and gasoline greatly reduced events of lead poisoning, yet unacceptably high rates of lead poisoning still occur. The effects of lead consumption are costly for both young and old; children may experience damage to the brain and nervous system, learning problems, and slowed growth; adults usually suffer from reproductive problems, high blood pressure and nerve disorders, to name a few. This research uses exploratory analysis of multiple databases such as the Toxic Release Inventory, air and water quality data, the National Health and Nutrition Examination Survey (NHANES), Childhood Blood Lead Surveillance Program (CBLS) and census data to gain a better understanding of the lead problem affecting the children of our nation. The analyses presented represent the first stage of research in a two semester project. The problem was provided by our client; Dr. Barry Nussbaum of the U.S. Environmental Protection Agency’s (USEPA’s) Office of Environmental Information. The research objective is to locate the next major source of lead contributing to elevated blood lead levels in U.S. children through exploratory analyses of public databases. Phase I consisted of identifying pertinent datasets for study and developing a method for combining these datasets into an analyzable form. Basic statistical analyses revealed several factors warranting further investigation, e.g. percentage of children under the age of six who are living in poverty, certain occupation types, and certain industries. Phase II of the research will concentrate primarily on more advanced analyses of the existing data, with the added goal of locating additional data sources, where applicable.

 

 


 

 

Student Author(s): 

Harness, Chad W.

Department(s):

Statistics

Research Mentor(s)

Thomas Reiland/Statistics

Title of Presentation:

Helping David Beat Goliath Again: Optimal Salary Strategies for Small-Market Major League Baseball Teams

 

 

Historically, baseball teams typically maximize winning percentage by maximizing player salaries, attracting top talent for top dollar. In order to remain competitive, small-market baseball teams must allocate their limited resources more effectively than their “big-city” counter-parts. Although increasing runs scored is an obvious strategy a team can adopt to raise its winning percentage, the optimal implementation of this strategy is not as clear when budgetary considerations are a significant limiting factor. By examining both offensive statistics and salary data for all Major League baseball players from 1995-2005 as well as offensive statistics for Major League teams over the same period, this study developed three empirical models aimed at simplifying this problem. The first model explains observed team runs as a function of a linear combination of the numerators for two widely used offensive statistics, slugging percentage and on-base percentage. The second model relates a statistic created by the researchers as a function of the same aforementioned numerators. This statistic, called “erg” for “estimated runs generated” estimates the runs contributed by individual players towards respective team totals. Significant results from analysis of variance of both models suggests, first, that the slugging percentage and on-base percentage numerators are useful predictors for team run production and, second, that these same independent variables are also highly related to our erg statistic. Finally, a third model relates individual player salaries to a standardized transformation of the erg statistic. Due to substantial variation in runs produced at any given salary point, LOESS smoothing is used to better approximate the relationship between individual salary and individual run production. Ideally, application of this model in allocating player salaries will mitigate the competitive advantage enjoyed by teams with substantially larger budgets.

 

 


 

 

Student Author(s): 

Hemperly, Joshua J.

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s)

Ryan P. Boyles/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

Estimating Daily Potential Evapotranspiration across North Carolina Using Radiation Estimates for the Penman-Monteith Equation

 

 

The United Nations Food and Agriculture Organization (FAO) Penman-Monteith equation is a standard method for estimating potential evapotranspiration. However, critical measurements needed for input into the equation are not routinely measured. The North Carolina Environment and Climate Observing Network (NC ECONet), maintained by the State Climate Office of North Carolina, collects observations from sensors that provide all the needed measurement to calculate FAO Penman-Monteith as well as evaportranspiration estimated by atmometers. This presents a unique opportunity to use observations to determine how well the FAO Penman-Monteith performs when coupled with the Hargreaves or Angstrom short wave radiation estimate equations. An accurate solar radiation estimate is important because at other weather observing locations operated by National Weather Service and the Department of Transportation there are no photovoltaic detectors, and thus no solar radiation measurements. By finding an accurate way to estimate solar radiation, the spatial and temporal representativeness of the FAO Penman-Monteith equation is expanded, and thus the potential for climatology of potential evapotranspiration in North Carolina increases. This study compared the performance of the modified FAO Penman-Monteith at nine ECONET sites across the state, three from each region, during the months of July through September for the years 2004 through 2006. This study revealed that the Hargreaves equation showed a lower overall error and bias than the Angstrom equation at all nine stations as compared to the atmometer-based observations. This study displayed the altitudinal bias in the Penman-Monteith equation when the three stations in the NC Mountains had the poorest performance. Due to the inherently turbulent nature of evapotranspiration it is expected that the true value and the estimated value will differ, however this study exposed the trend that the FAO Penman-Monteith has poorer performance with a consistently low potential evapotranspiration value when compared to a moderate or high value.

 

 


 

 

Student Author(s): 

Hoffman, Torissa J.

Stevens, Derrick

Ojha, Satyajeet Sooryakant

Mccullen, Seth

Roberts, Wes

Department(s):

College of Physical and Mathematical Science, Textile Engineering Chemistry and Science

Research Mentor(s)

Laura Clarke/Physics

Russell Gorga/Textile Engineering

Title of Presentation:

Achieving Electrically Conductive Polymer Mats with Minimal Doping by Tuning Fiber Morphology

 

 

My project involves the developing of electrically conducting scaffolds that could be used for tissue engineering where the conductivity of the scaffold allows for the electrical stimulation of the cells. Electrically conducting mats have a similar fiber size and porosity to a human’s extracellular matrix, which is coordinated with the growth, repair and proper functions of tissue. These mats are conductive due to the presence of conducting particles, such as multi-walled carbon nanotubes or silver nanoparticles, within the polymer fibers, which make up the mat. The polymer/particle fibers are created by a process called electrospinning (made by collaborators in Gorga group). Most materials, such as metals, are conductive because of properties of each of their atoms or molecules. In contrast, our mats are a mixture of conducting particles and insulating polymer. They become conductive when there is sufficient density of particles so that the particles touch and form a path across the sample. As physicists, we are interested in this fundamental process, which is called percolation. In particular, our electrical measurements show that the percolation threshold (the minimum amount of particle to achieve conductivity) changes for different types of morphologies of the fibers in our mat. The three different morphologies we have tested are a solid fiber, a core-sheath fiber, and a film. From our data we have discovered that the percolation threshold of the core-sheath fiber mat is lower than that of a solid fiber mat. In my poster, I’ll discuss our hypotheses for this effect and our future work.

 


 

 

Student Author(s): 

Hopkins, Alyssa M.

Department(s):

Marine, Earth and Atmospheric Science

Research Mentor(s)

Blake A. Schaeffer/Oceanography

Title of Presentation:

Using Optical Techniques to Identify Case Waters in the Galapagos Marine Reserve

 

 

There are two major current systems that converge on the Galápagos Marine Reserve (GMR); the Equatorial Undercurrent (EUC) and the South Equatorial Current (SEC). As the Intertropical Convergence Zone (ITCZ) migrates seasonally, different source waters supply the SEC carrying optically unique constituents such as detritus and colored dissolved organic matter (CDOM). Absorption of these constituents was derived from remote sensing reflectance (Rrs), defined as the ratio between upwelling and downwelling radiance at the surface. Rrs was derived from a hyperspectral HyperSAS and multi-spectral Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite in March and November 2005. The HyperSAS provided high precision hyperspectral measurements of water-leaving sea surface reflectance while mounted onboard a ship. MODIS Aqua satellite generated large scale 1 km resolution images of the GMR waters. The Quasi-Analytical Algorithm (QAA) calculated absorption of phytoplankton and detritus/CDOM from the Rrs. Pixels from MODIS that corresponded with the latitude and longitude of the HyperSAS measurements were used for satellite validation. Linear regressions identified shipboard measurements were correlated with the satellite data. Absorption contributions by phytoplankton and detritus/CDOM were identified. In the future, multi-spectral (MODIS satellite) and hyperspectral data collections will help track seasonal and inter-annual variability in the water masses, which should prove invaluable in monitoring and managing the ecological resources (fisheries and dive tourism) of the Galápagos National Park.

 


 

 

Student Author(s): 

Hornsby, Fawn E.

Department(s):

Statistics

Research Mentor(s)

Marcia Gumpertz/Diversity and African American Affairs

Title of Presentation:

How Missing Census Tract Information May Be Associated With Early and Late Stage Breast Cancer in Addition to Other Demographic Factors

 

 

By modeling the proportion of cases of advanced disease in a population group, we can provide insights into breast cancer control strategies; however, when information about a patient is missing, that patient is left out of the analysis. Census tract information can be linked to sociodemographic factors that would be helpful in identifying subpopulations that would be at high risk for late stage breast cancer. Out of a total of 26,565 cases, 747 were missing the tract identifier. A logistic regression modeling the odds of advanced breast cancer by race was fit to data from the 1990 decennial census data file and data from the SEER program. The variables in the model included demographics such as age, marital status, country of birth, year of diagnosis, census tract of residence, and tumor biology variables. By examining which cases were missing the tract information, we found that the odds of being diagnosed late stage disease depended on whether their tract information was missing for certain racial groups. For Asians, the odds of being diagnosed with late stage breast cancer when missing the tract information are 2.73 times the odds if tract information was present. Additionally, for the Black and White racial groups, the effect of age is dependent on whether the tract information is missing. Despite these findings, there does not seem to be a difference in the probability of late stage diagnosis when cases had the tract compared with those that did not have the tract information. Furthermore, a model was developed to determine the factors associated with missing tract information. We found that birthplace, reporting source, (hospital, lab, doctor’s office, autopsy, death certificate) and year were significant predictors, while age, race, and marital status were not.

 

 


 

 

Student Author(s): 

Lakhani, Amit M.

Department(s):

Physics

Research Mentor(s)

Thomas P. Pearl/Physics

Title of Presentation:

Investigation of Chiral Thin Films of Tartaric Acid on Ag(111)

 

The expression of chirality in monolayer, molecular domains on surfaces has important implications for enantioselective catalysis and chemically tuned thin films. The organizational structure of a chiral molecule, tartaric acid (C4H6O6), weakly bound to an achiral metal surface, Ag(111), has been studied with low temperature scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Molecularly resolved images of both (R, R)- and (S, S)- tartaric acid enantiomers on Ag(111) highlight the role of intermolecular hydrogen bonding in stereospecific domain and superlattice formation. Proposed structures (as related to adsorption geometry) have been determined from the experimental data for the enantiomerically pure thin films on the Ag(111) lattice. Additionally, chiral domain formation and phase separation from a racemic mixture of both tartaric acid enantiomers has been studied. Finally, scanning tunneling spectroscopy experiments have been used to confirm the weak binding of tartaric acid to the metal surface.

 

 


 

 

Student Author(s): 

Landwehr, Justin G.

Department(s):

Statistics

Economics

Research Mentor(s)

Thomas Reiland/Statistics

Title of Presentation:

Predicting Time to Next Foul in Basketball

 

In basketball at any level, coaches inevitably must decide whether to play or sit a player in foul trouble. Using data from the National Basketball Association, we attempt to accurately predict a player’s time to next foul using the gamma distribution and two simple statistics: total fouls, and total minutes played.

 

 


 

 

Student Author(s): 

Miles, Travis N.

Department(s):

Marine Earth and Atmospheric Sciences

Research Mentor(s)

Blake Schaeffer/Marine Earth and Atmospheric Sciences

Title of Presentation:

Relative Phytoplankton Concentrations During Normal and Mild El Niño Conditions in the Galapagos Archipelago Determined through In-Situ Absorbance in an Optical Phytoplankton Discriminator

 

 

Discrimination of phytoplankton community composition throughout the Galapagos Marine Reserve (GMR) is presented from a state-of-the-art Optical Phytoplankton Discriminator (OPD) instrument. A single absorbance signal exists for each phytoplankton pigment. Taxonomic groups of phytoplankton have specific combinations of these pigments in the forms of chlorophylls, carotenoids and phycobiliproteins. This specific combination of pigments gives the taxonomic groups a characteristic spectral signature. The spectra of in-situ samples identified absorption bands of different pigments present in natural populations of phytoplankton. Therefore, composition and dynamics of phytoplankton populations were inherent to spectral data. The OPD generated surface spectral absorption curves for phytoplankton composition differentiation throughout the GMR on two field studies. The first cruise was June 2006 when the El Niño Southern Oscillation conditions were relatively normal. The second cruise was November 2006 at beginning of a mild El Niño. El Niño produces abnormally warm conditions in the equatorial Pacific and prevents the movement of nutrient-rich subsurface waters to the surface that would occur under normal conditions. The reduction in plant nutrients starves the entire ecosystem beginning with the composition of phytoplankton and extending all the way to the top of the food chain. On shorter time-scales, the GMR acts as a natural experiment for measuring the effects of annual to inter-annual variability on flora and fauna. We identify phytoplankton community composition changes between normal and El Niño conditions.

 


 

 

Student Author(s): 

Onori, John E.

Department(s):

Polymer and Color Chemistry

Research Mentor(s)

Richard Kotek/Polymer and Color Chemistry

Title of Presentation:

Viscosity Measurements of Cellulose in ED/KSCN Salt System

 

 

Cellulose is a natural polymer which is found in trees and plants and is commonly used for making milk and juice cartons. The problem with cellulose is that it does not melt and dissolve in the common solvents. Cuen (copper-Ethylenediamine complex) solution is the only solvent used for viscosity measurements of cellulose. The objective of this experiment is to take a similar solvent like Potassium Thiocyanate Ethylenediamine system, dissolve different types of cellulose and take viscosity measurements to find there intrinsic viscosities. Each cellulose sample was ground up, dried in a vacuum oven over night and measured on an analytical balance. 125 ml flask equipped with a mechanical stirrer was used for dissolution. Ethylenediamine and potassium Thiocyanate were added in first to create the solvent, and then the cellulose sample was added in, it took about 24-48 hours for the complete cellulose dissolution. An Ubbelohde viscometer, the constant temperature bath (held at 25oC) and a stop watch was used to determine the flow times of each solution. Intrinsic viscosity was calculated using a series of equations that included relative, specific, reduced, and inherent viscosities. Intrinsic viscosity was found by plotting reduced and inherent viscosity vs. cellulose concentration and extrapolating reduced and inherent viscosity back to the zero concentration. These two viscosities should meet at the same point. We were successful in finding the intrinsic viscosity of Waco DP 210. Both Inherent and reduced viscosity agreed with each other. Future work will be to find intrinsic viscosities of different types of celluloses.

 


 

 

Student Author(s): 

Pronschinske, Alex M.

Department(s):

Physics

Research Mentor(s)

Thomas P. Pearl/Physics

Title of Presentation:

Adsorption of 8CB Liquid Crystals on Poled, Lithium Niobate (001)

 

Extensive research has been done on the properties of liquid crystals and ferroelectric materials separately that has led to important applications, yet the two substances have not been studied in a combined system. In our study we examine the wetting and ordering properties of 4'-octyl-4-biphenylcarbonitrile (8CB) liquid crystals on a ferroelectric (001) cut lithium niobate (LN) surface. The single crystalline LN samples are uniformly poled such that the two opposing faces of the crystal along the z axis have equal charge densities but opposite polarity. Due to the strong dipole moment of the 8CB liquid crystal we believe that the molecule experiences a charged domain specific interaction with the LN surface dictating the molecular alignment. We observe the surface characteristics of LN and the wetting behavior of 8CB under different deposition times to gain insight to the formation of the thin liquid crystal film, as low as a single molecular layer. To do this we use a combination of surface sensitive tools including atomic force microscopy (AFM), surface contact angle measurement, X-ray photoelectron spectroscopy (XPS), and low energy electron diffraction (LEED).

 


 

 

Student Author(s): 

Ribeill, Guilhem

Sakon, John J.

Department(s):

Physics

Research Mentor(s)

Keith Weninger/Physics

Title of Presentation:

Fluorescent Single Molecules Inside Cells

 

 

Single molecule studies, such as those using fluorescent techniques have seen increasing use in the investigation of the dynamics of the cell. Toward this goal we have written custom software in MATLAB that can track single particles from video fluorescence microscopy in living cells. We have tested the software by locating and tracking fluorescent beads in vivo. We are using SNARE proteins tagged with two fluorescent dyes in our efforts to demonstrate the ability to detect FRET from individual proteins inside live cells.

 

 


 

 

Student Author(s): 

Secreast, Sarah M.

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s)

Anita McCulloch/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

Distribution of Phytoplankton Populations in the Surrounding Waters of the Galapagos Islands

 

 

Many species of phytoplankton are an integral part of the food chain. They can serve as the main primary producers of different water systems, especially in oceanic systems. I conducted research on the different species of phytoplankton in waters surrounding the Galapagos Islands, Ecuador. Multiple currents converge at the Galapagos Islands creating a variety of bioregions. The Galapagos Islands have a diverse array of marine species, such as phytoplankton, that inhabit the surrounding waters. Samples of phytoplankton were taken from the many different bioregions. These samples were analyzed to determine the type, the species, and the relative distribution of the different classes of phytoplankton.

 


 

 

Student Author(s): 

Speller, Danielle H.

Department(s):

Physics

Research Mentor(s)

Gail McLaughlin/Physics

Title of Presentation:

Predicting the Explosions of Stars

 

 

One of the most valuable systems in the study of stellar evolution and cosmological processes is the supernova. Violent explosions of massive stars produce extraordinary amounts of energy, particularly in the form of photons (light quanta) and neutrinos (nearly massless elementary particles), and are the birth place of most of the heavy elements required for life on earth. Supernovae are rare events, and it is impossible to determine the exact time or location, which is usually detected via the emitted light. We investigate a new method of detection based on the principle that most large stars are cooled primarily via the release of neutrinos, and these neutrinos are produced in exceptional amounts right before the moment of star collapse. By detecting these presupernova bursts, our efficiency of observation and use of instrumentation will be greatly enhanced. Our research focuses on the luminosity of the neutrinos and the likelihood of detection in earthbound neutrino laboratories.

 

 


 

 

Student Author(s): 

Warren, Joshua

Department(s):

Statistics

Research Mentor(s)

William F. Hunt Jr./Statistics

Title of Presentation:

Understanding Historical Emission Trends

 

 

Air pollution is harmful to people and the environment. In order to better understand the nature of the environmental problem, emission inventories are developed for all sources in an area. They are based upon engineering estimates. They represent both gases and particles of air pollution that are emitted into the air by a variety of sources. Emission inventories (E/I) change over time and may be reduced as result of emission control programs. The U. S. Environmental Protection Agency’s (USEPA) Office of Air Quality Planning and Standards (OAQPS) is responsible for the National Emissions Inventory (NEI). Emissions data are collected by state, local, and tribal and the federal governments. The E/I includes a number of different sources: (1) Point sources – stationary locations of pollution include factories, pulp and paper mills, petroleum refineries, electric power plants, etc.; (2) Mobile Sources - cars and trucks, airplanes, etc.; (3) Biogenic sources – natural sources of emissions – trees, animals, etc.; (4) Area Sources – small stationary source of emission such as dry cleaners and degreasing operations. Future emissions are critically important when trying to determine the impact of air quality standard regulations that are protective of human health and the environment. How will regulations impact sources in the future making changes needed to reduce emissions to achieve the air quality standards? Emissions inventories are projected for future years to conduct analyses for our rulemakings. The methods for forecasting emissions into the future are complex. The objective of this project is to improve upon the existing method to forecast future emissions. Two sectors will be examined to forecast future emissions – petroleum refineries and chemical manufacturing. The pollutant that will be examined is nitrogen oxides. We will try and take technological change into account using gross domestic product and other variables. The Presidents Energy Plan to reduce oil consumption by 20 percent in 10 years will be used to forecast future emissions. Different alternatives will be examined in the paper.

 

 


 

 

Student Author(s): 

Wilson-Short, Gareth B.

Department(s):

Chemistry

Research Mentor(s)

Mike. H. Whangbo/Chemistry

Title of Presentation:

Ab-Initio Study of Magnetic Interactions in a Disordered Delafossite-Type System

 

 

The delafossite-type system Ag2CuMnO4 displays crystalline disorder between Cu2+ and Mn4+, and the refined high-symmetry crystal structure does not contain the expected (CuO6)10- Jahn-Teller distortions. Ag2CuMnO4 exhibits high temperature ferromagnetic properties arising from net magnetic moment in the transition-metal-oxide layers. This moment is quenched at lower temperatures due to antiferromagnetic order between layers [1]. This study seeks to address the possible origins of this net-moment by parameterizing a Heisenberg Hamiltonian (i.e. calculating spin-exchange parameters) using the Vienna Ab-initio Simulation Package (VASP). Although preliminary calculations reveal small, but non-negligible, antiferromagnetic interlayer interaction, the intralayer magnetic interactions were the focus of this study. Several simple arrangements of copper and manganese were optimized by relaxation of ionic positions, and then spin-polarization was introduced to model different magnetic solutions and perform mapping analysis of the intralayer interactions. It was necessary to introduce a Hubbard U parameter on the copper site to capture insulating behavior. Calculations of varying structure and Hubbard U-values yielded relatively strong antiferromagnetic Cu---Mn interactions within the metal-oxide layers. This result suggests that the high temperature net-moment arises from intralayer ferrimagnetism, rather than the ferromagnetism concluded by experiment [1]. Although disagreement with Goodenough-Kanomori rules may be ignored via chemical argument in the case of eg - p - t2g interactions, disagreement with experiment suggests that the assumptions involved in reaching this conclusion were poor. Computational methods and finer details of results will be presented.


 

[1] D. Muñoz-Rojas, et al "Ag2CuMnO4: A new silver copper oxide with delafossite structure" J. Solid State Chem 179 (2006) 3883-3892

 


 

 

Student Author(s): 

Wootten, Adrienne M.

Antczak George

Harris, Jordan M.

Department(s):

Marine Earth and Atmospheric Sciences, Statistics

Research Mentor(s)

William F. Hunt Jr./Statistics

Title of Presentation:

Can Meteorologically Adjusted Ozone Air Quality Trends Identify the Impact of the Presidential Nitrogen Oxide Reduction Policy?

 

 

Ozone trends are often used to see the impacts of emissions control standards across the country. These raw data trends are interlaced with the varying effects of meteorology and thus difficult to draw sound conclusions upon. Many different techniques have been created to counteract meteorology. The result of this project is a time series model which removes the effects of meteorology along with those of autocorrelation and leaves the true value of ozone concentration before(pre-2003) and after the Presidential reduction policy. The model was developed using ozone data and meteorological data from the Maryland Department of the Environment. The data set used spans April through October of 1997-2006 for the measuring sites in the states of Maryland and Washington D.C. Analysis began with quality control on each of the sites for data completeness. Once this was finished, the site was chosen that was closest to our meteorological data station, BWI Thurgood-Marshall Airport (BWI). The location closest to BWI was picked because of the ability to merge the data from the ozone site and the weather site with minimal error. A general linear model was first used to analyze the trend, followed by a test for autocorrelation using the Durbin-Watson statistic. Final results of this project to be presented at the conference.

 

 


 

 

Student Author(s): 

Zapata, Cheryl L.

Department(s):

Mathematics

Research Mentor(s)

Mette S. Olufsen/Mathematics

C. T. Kelley/Mathematics

Hien Tran/Mathematics

Title of Presentation:

Blood Pressure and Blood Flow Variation during Postural Change from Sitting to Standing: Model Reduction and Improvement

 

 

Short term cardiovascular responses to postural change from sitting to standing involve complex interactions between the autonomic nervous system, which regulates blood pressure, and cerebral autoregulation, which maintains cerebral perfusion. We have developed a model which can predict dynamic changes in beat-to-beat arterial blood pressure and middle cerebral artery blood flow velocity during postural change from sitting to standing. This model uses an electrical circuit analogy, predicting changes in blood pressure (voltage) and blood flow (current) as functions of resistance and compliance (capacitance). The base model has more than 100 parameters that must be identified to predict regulatory response for individual subjects. In preliminary work, an inverse least-squares problem was formulated to estimate all 100 parameters to minimize the difference between observed data and computed values. This optimization process is time-consuming and not feasible if the model is to be validated against multiple datasets. In other preliminary work on a 52 parameter steady state model, sensitivity analysis was used to identify a small number (approximately 20) of sensitive parameters. We have shown, using sensitivity analysis, that it is possible to reduce the structure of that model and that with additional data it is possible to identify more parameters. Sensitivity analysis is being use to reduce the 100 parameter model to allow for a more efficient identification of the model’s parameters and possible model reductions.

 


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Last modified February 2007 by Sharon E. Hunt, WordHunting