Natural Science Seminar

Abstracts Fall, 2002

Julianna da Frota
September 16, 2002
An investigation of a new method of extracting phthalate monoesters using Acrodisc filters
Mentors: Dr John Brock and Dr Louise Weber

Abstract: During part of the creation of a new method of phthalate monoester extraction in breast milk, Acrodisc filters were added and the phthalate monoesters disappeared.  Phthalates can produce altered sertoli cell function, hypospadius, fetal death, and birth defects in rats as well as altered semen quality in humans.  This investigation compares the phthalate monoester extraction in Acrodisc filters to the extraction in Nexus columns, and compares the extraction at three pH levels.  A standard solution (100 ppm monobutyl phthalate (MBP) and 100 ppm ethylhexyl phthalate (MEHP)) at three pH levels was pushed through a 10 ml syringe and an Acrodisc syringe tip filter at 2 ml intervals until 8 mls were filtered.  Likewise, the solutions were pulled through a Nexus column after a wash of ethyl acetate, acetonitrile, and solution at a similar pH.  All samples were then analyzed using HPLC MS/MS at Lund University in Sweden.  There was not a significant difference (p > 0.05) in the percent recovery of phthalate monoesters in Acrodisc extraction in comparison to the original unfiltered solution.  In contrast, the recovery of extracted phthalate monoesters was significantly different (p = 0.05) than the unfiltered solution in Nexus columns.  As a result of this study, Acrodisc filters are not the problem with the missing monoesters, and these filters can be used as filters without extracting phthalate monoesters.  The findings also complete the development of a new method of phthalate monoester extraction in breast milk, which may help identify sources of phthalate exposure in infants.

Doug Lane
September 16, 2002
A Study of the Bluebird Boxes at Warren Wilson College
Mentor: Dr. Lou Weber

Abstract:  The eastern bluebird (Sialia sialis) has been in a major population decline for the first 75 years of the twentieth century.  Much of this loss has been due to human changes that reduce the amount of cavities available for bluebirds to breed in and competition from introduced species.  In the late 1970’s humans started to help the bluebird in finding new cavities by erecting nest boxes along bluebird trails.  The Biology and Environmental Studies departments at Warren Wilson College have been trying to help for several years.  Unfortunately before this study we were unaware of where all of our nest boxes were located, if they were being used and by what species, and if any pattern exists in their use that could provide information to improve future efforts.  My objective was to answer these unknowns and provide any additional information that may be useful to our aid of the eastern bluebird.  I mapped and monitored each box to find what species if any was using them, measured any quantifiable aspect of placement, and compared the data to find a pattern if one existed.  I found and mapped 18 bluebird boxes with a total of 11 bluebird nests, 5 of which had active bluebirds in them.  Three of these boxes had other species in them.  There was no pattern found in my quantifiable data.  WWC is doing well in our aid to the eastern bluebird.  Our population is growing as shown by 10 parents producing 15 chicks that fledged.  Installation of predator guards is highly recommended along fencerows.  There are currently plans to expand the amount of nest boxes that we have available and further help the bluebirds that come use the campus by installing predator guards.

Naomi Ndavu
October 7, 2002
Impact of Warren Wilson Farm on Water Quality of Two Campus Streams before Restoration
Mentor: Dr. Mark Brenner

Abstract: Grazing of animals in pastures close to watersheds and runoff from agricultural fields and feedlots are a major source of non-point water pollution. Warren Wilson College is committed to reducing these types of inputs and restoring local streams.
This study compared water quality within two streams to obtain data prior to the restoration. Concentration of ammonia (NH3) and phosphate (PO4), total suspended solids (TSS) and biological oxygen demand (BOD) were measured as indicators of water quality.  Three sub-samples were collected from each upstream and downstream site. Four samples were collected in the spring of 2002 and four in the summer of 2002.

The results were analyzed using a paired t-test. A comparison of the amount of TSS upstream and downstream did not have a significant difference in either stream; the p-value for the Swim Pond Stream was 0.4374 while that for Berea Stream was 0.3421. The concentration of BOD showed no significant difference within the two streams; the p-value for the Swim Pond Stream was 0.4422, while that for Berea Stream was 0.2054. Comparison of NH3 upstream and downstream was significant in the Swim Pond Stream with a p-value of 0.0393; this was probably due to the animals that live in the pond and nitrification by bacteria. There was no significant difference in Berea Stream, with a p-value of 0.2443. The comparison of PO4 was extremely significant in Berea Stream with a p-value of 0.0007. This could be due to the rocks that form the riverbed, and due to runoff from the adjacent pasture. The Swim Pond Stream had a p-value of 0.4024, which was not significant. It should be noted that these samples were collected during a drought period and hence the data obtained does not provide an accurate idea as to what is happening within the streams.

Choong Teow
October 7, 2002
Analysis of the ingredients of Dong Quai, Angelica Sinensis.
Mentor: Dr. Dean Kahl

Abstract: Dong Quai is a popular oriental herb that is widely used to treat illnesses. It is also commonly used as food flavoring. Thirty-five components have been isolated from Dong Quai. Two of the major components are Z-ligustilide and gamma-terpinene. The purpose of this research was to determine the composition of Dong Quai root oil and also to compare Dong Quai root oil made from Chinese and Malaysian roots. The analysis involved a standard root pill, Dong Quai root from China, and Dong Quai root from Malaysia. The essential oils of Dong Quai roots were isolated by steam distillation. The distillate was collected, and the essential oil was extracted with diethyl ether. The essential oil was analyzed by gas chromatography/mass spectrometry. The two major peaks in the total ion chromatogram (TIC) were due to Z-ligustilide and gamma-terpinene. The mass spectra were characteristic for each compound. The mass spectra for the root pill, root from China, and root from Malaysia were similar to the mass spectra obtained from research carried out in China by Y. Chen’s research group. The TIC showed that the ratios of gamma-terpinene to Z-ligustilide in the essential oils were reasonably close for the three samples. Since this research is a preliminary study, additional research is required because there were no internal standards, and there were no replicates. A search of the medical literature showed that gamma-terpinene is a skin irritant, whereas Z-ligustilide is a muscle relaxant. Z-ligustilide also has antiasthmatic effects as well as anticholinergic effects. However, there is no clear connection with the claimed medical effects.

Hughes Sanders
November 4, 2002 
Changes in Social Behavior in the Mantled Howler Monkey (Alouatta palliata) due to Infant Presence
Mentor: Dr. Robert Eckstein

Abstract: The mantled howler monkey is a New World primate that ranges from Central to South America.  The conservation status of this species is currently listed as low risk for extinction, perhaps due to the large demographic area that is covered by howler monkeys.  In 1997 a group of scientists working in collaboration with the Nicaraguan government established the Ometepe Biological Field Station.  Ometepe Island is located in Lake Nicaragua, which lies in southern Nicaragua.  The purpose of my study was to determine the influence of infants on female&rsquo;s social relationships, in regards to the amount of time spent in proximity to other members of the social group.  Previous studies show that both male and female howlers behave aggressively towards infants.  A focal animal sample with three-minute time intervals was conducted.  Data was collected on the distance that both mothers and non-mothers maintained with other adult members of the social group.  The data show a significant difference (p<.0001) between mothers and non-mothers proximity to members of the social group.  The data do not yield a significant difference (p=.5857) between mothers holding their infants and mothers not holding their infants.  The results of this study suggest that mothers spend more time away from members of the social group than non-mothers.

Kirkdale Guy
November 25, 2002
Fabric Dyes in the Asheville Sewage Treatment System
Mentor: Dr. J. Brock

Abstract: Fabric dyes are a means of applying color to fabric. One method of dyeing fabrics is to submerge the fabric in a dye solution allowing the dye to react with the fabric leaving the fabric colored. Using the process of a dye bath produces an excess of dye dissolved in gallons of water or dyeing medium. The waste of the dyeing process is an issues because in Asheville North Carolina, fabric dyes are legally dumped into the sewage treatment system which does not filter to remove chemicals before the effluent is dumped into the French Broad River. My objective was to develop a method using high pressure liquid chromatography to analyze for the presence of the dye. My second objective was to then develop a calibration curve for a specific dye and to analyze for the presence and concentrations of the dye, if present. A set of standards was created using dyes obtained from Lustar, a local dyeing company. The standards were used to generate a calibration curve that was later used to relate detector response to dye concentration. The limit of detection of the instrument was calculated by analyzing water blanks to correct for background noise. The limit of detection was determined to be 6.0 parts per billion (ppb). From the effluent samples collected at the sewage treatment plant, the concentration of Remazol blue fabric dye was below the 6.01 ppb calculated detection limit in all samples collected. There was however a red compound present in the effluent that could be isolated using solid phase extraction. The red compound produces a wavelength of 254 nm.

Alice Baker
December 2, 2002
Effects of Decreased Deworming on the Warren Wilson College Beef Cattle Herd
Mentor: Dr. Jeff Holmes

Abstract: Warren Wilson College beef cattle are raised on a rotational grazing system.  This rotational grazing may limit the transmission of parasitic worms, if the worm load on the pastures is already low.  This experiment was conducted to determine if worm loads are higher in cattle dewormed once a year rather than twice a year, and to determine if weight gains were higher in cattle dewormed twice a year rather than once a year.  This decreased deworming may be beneficial in slowing the development of resistance in nematode populations, may reduce the impact on the environment (dung beetle larvae), and may reduce the cost of deworming to farmers.  The yearling cattle showed no significant difference in weight gains (p-value 0.59), the adult cows produced no significant difference in weight change (p-value 0.86), and the calves showed no significant difference in weight gains (p-value 0.70).  The comparison of egg concentration was also not statistically significant (p-value 0.65) between cattle dewormed once a year versus twice a year.  These results do not necessarily suggest abandoning the use of synthetic dewormer on Warren Wilson College cattle, but they do suggest a decreased deworming program that includes increased health monitoring may be acceptable.

Steven M. Ritt
January 27, 2003
Glycoalkaloids in the Nightshade Family
Mentor: Dr. Dean C. Kahl

Abstract: Folklore has long considered the nightshade family (Solanaceae) of plants to be poisonous, and there are compounds present in these plants thought to aggravate the conditions of arthritis.  This problem may be due to the presence of the neurotoxins a-solanine and a-chaconine in these plants.  The purpose of this project was to develop a method to analyze glycoalkaloids in tomatoes.  Analysis of these glycoalkaloids was first performed using the Spectra Physics High Performance Liquid Chromatograph (HPLC), but the instrument was not sensitive enough for the detection of glycoalkaloids.  Analysis was then continued using a newer and more sensitive instrument, the Shimadzu HPLC.  However, there were numerous technical difficulties with the Shimadzu HPLC, and the detection of a-solanine and a-chaconine was not possible using this instrument.  Given the problems with the HPLC instruments, a simple and rapid means of analysis using thin layer chromatography (TLC) was developed.  Preliminary results showed that the glycoalkaloids, a-solanine and a-chaconine, could be separated from the aglycone, solanidine, using reverse phase TLC plates and an acetonitrile- ammonium phosphate buffer (50+50).  However, the glycoalkaloids, a-solanine and a-chaconine could not be separated.  These results suggest that thin layer chromatography can be used to identify glycoalkaloids in plants of the nightshade family.

Melissa Meyer
February 17,  2003
Pyrolysis of Newspaper and Magazines
Mentor: Dr. Dean Kahl

Abstract: Extensive research has been done on the pyrolysis of wood.  Newspaper and magazines contain the same materials as wood and may potentially yield the same products from pyrolysis.  This method could be used as most of the products have a potential for fuel and chemicals. In addition, this technique could be used to decrease the amount of paper waste. The purpose of this project was to determine whether newspaper and magazines could be converted to charcoal and chemicals using pyrolysis.  This experiment was done by heating newspaper and magazines in a distillation apparatus under nitrogen.  The products from this experiment include charcoal, an aqueous phase, an organic layer, and gases.  The charcoal was burned in a furnace to determine residual ash.  There was no significant difference between the charcoal yield of newspaper 42% and magazine 49% giving a p-value of 0.0606 using the Mann-Whitney test. There was also no significant difference between the amounts of gas, water, and organic products between magazine and newspaper with p-values 0.6650, 0.0606, 0.0606 respectively.  The residual ash shows a significant difference between the newspaper (0.08) and magazine (1.03) with a p-value of 0.0265.  This fact means residual ash should not be a problem in charcoal production.  The charcoal, gas, organics, and water from this experiment produced yields comparable to previous research but using a low-tech alternative.  This method could be used in less developed countries to reduce deforestation while making use of paper waste.

Rachel Horn
Feb 24, 2003
Classification of Clay and Archaeological Pottery byChemical Composition

Abstract: How much can we learn about a potsherd through chemical characterization?  Was this potsherd brought here from another village?  Where did the Native Americans collect the clay they used to make their pottery?  How much does the clay change chemically when it is fired?  These questions can all be answered using chemical methods.  This study measured the chemical composition of clays and pottery from eight different sites.
SampleGroup    Location
1 Big Bottom Field Clay
2 Horse Pasture Clay
3 Ballfield stream Clay
4 Fired Ballfield Clay
5 Early Macon County Site Potsherds
6 Late Macon County Site Potsherds
7 Warren Wilson Site Potsherds
8 Burke County Site Potsherds

All samples were soaked in  1M HCl for one week.  The concentrations of  Ca, Ba, Sr, Mg, and Fe were measured using  Inductively Coupled Plasma ( ICP). Multiple Analysis of Variance (MANOVA)  showed that the three clays (samples 1-3) could be distinguished from the pottery and each other.  In addition pottery from different time periods at the Burke site (5, 6) did not differ (P value 0.09).  However MANOVA did not clearly distinguish potsherds from different sites (5+6, 7, 8). Multivariate analysis can give us clues about chemical patterns in the potsherds. Principal Component analysis uses functions, which account for almost all the variability in the data set to look for patterns in the data.  Here are the actual functions for the principal component analysis graph.

PC1 = 0.004*lnFe-0.552*lnCa-0.815*lnBa-0.172*lnSr-0.023*lnMg PC2=0.542*lnFe+0.090*lnCa-.0193*lnBa+0.557*lnSr+0.592*lnMg

These functions create a scatter plot which allows  the data to be visually represented.  Composition patterns emerge in this scatter plot, indicating that chemical composition can be used to suggest the source of clay for a pot.  Therefore, Native American potters at the WWC site apparently did not use any of the clay sources sampled here.  With enough samples this method could source a single potsherd to a single clay source.

Nathan Jones
March 3, 2003
Metals in Urine of Smokers and Nonsmokers
Mentor: Dr. John Brock

Abstract: Smoking of tobacco and non-tobacco products produces exposure to numerous toxins. Many of these compounds promote tumor cell growth. Smoking-related toxins include carbon monoxide, tar, nicotine, polyaromatic hydrocarbons, and cadmium. Cadmium, a heavy metal, has been shown to be toxic at low levels of exposure. Smoking is the primary source of cadmium exposure in the general human population. Individuals who smoke heavily on a regular basis have been shown to exhibit elevated levels of urinary cadmium compared to nonsmokers. The purpose of this experiment was to test if differences exist in urinary levels of metals between populations of nonsmokers, smokers of tobacco products, and smokers of non-tobacco products. Individuals participated anonymously in an experiment in which 24-hour urine samples were collected and analyzed using various analytical instruments. The samples were analyzed for metal concentrations and the data was analyzed using both parametric and nonparametric tests. The p-values from the analysis suggested no difference between the means for any of the analytes. The data implies that smoking does not tend to increase urinary levels of cadmium, mercury, or chromium. However, the results may be limited due to the small, highly variable human populations.

Sarah Stokes
March 3, 2003
Toxicity of dibutyl phthalate to zebrafish (Danio rerio) embryos
Mentor: Dr. Jeff Holmes

Abstract:  Phthalates are a class of chemicals manufactured on a global scale in large quantities.  They are used in numerous products ranging from plastic goods to personal care products.  Animal testing has demonstrated significant toxicity of phthalates, especially in the early stages of development.  Zebrafish embryos develop quickly, outside the body, and have transparent embryos, which makes them suitable organisms to use as models for vertebrate development.  The purpose of this experiment was to determine the lethal dose of phthalates for zebrafish embryos.  To do this, dose-response curves were constructed for the percent mortality of zebrafish embryos to dibutyl phthalate and LD50 concentrations for 24 and 48 hours of exposure were calculated.  The average LD50 concentration for 24 hours was 1.2 ppm and the average LD50 for 48 hours was 2.4 ppm.  The concentrations of dibutyl phthalate found to be lethal to zebrafish in this experiment are comparable to the concentrations of phthalates to which humans are exposed.  This result may have important human health implications, especially for developing fetuses.

Tamara Todd
March 10, 2003
Conjugated Linoleic Acid in Egg Yolks from Chickens at the Warren Wilson College Farm
Mentor: Dr. Victoria Collins

Abstract: Conjugated linoleic acid (CLA) is an isomer of the 18 carbon unsaturated fatty acid linoleic acid. CLA is found in products from ruminant animals. CLA has been shown to be anti-mutagenic, anti-carcinogenic, anti-atherosclerotic, anti-diabetogenic, and can reduce adipose tissue. The first objective of this study was to produce eggs enriched in CLA by feeding a CLA supplement to hens. The second objective of this study was to compare the fatty acid composition of eggs from chickens living indoors and chickens with access to the outdoors.  Laying hens were divided into four indoor pens and four outdoor pens. All eight pens were fed a control diet (standard layer diet + 1% soybean oil) for three weeks. Eggs were collected during the third week and egg yolks from each pen were pooled. All eight pens were then fed the experimental diet (1% CLA) for three weeks. Eggs were collected during the third week and yolks were pooled for each pen.  Fatty acids were extracted from the yolks, trans-esterified, and analyzed by gas chromatography. Fatty acid composition was analyzed by two way ANOVA. The two factors, diet and housing, showed no significant interaction. The effect of diet on egg composition was significant (p<0.05) for all fatty acids measured.  Saturated fatty acids increased and unsaturated fatty acids decreased when CLA was added to the diet. The relative amount of CLA increased from 0% of total fatty acids to ~1.5% of total fatty acids upon CLA supplementation. The effect of housing on fatty acid composition was only significant for stearic acid, which was lower in eggs from outdoor chickens (p<0.05). All other fatty acids showed no significant difference between the indoor and outdoor groups (p>0.5).  Hens fed 1% CLA produced eggs containing approximately 30 mg of CLA per egg.  For producers of &ldquo;designer eggs&rdquo;, supplementing with CLA may be profitable. The effect housing on fatty acid composition needs further exploration.

Sarah Leavitt
March 10, 2003
The effect of the stress of being handled on the growth of piglets on the Warren Wilson College farm
Mentor: Dr. Robert Eckstein

Abstract: Pork sales are a major profit on the Warren Wilson College farm.  Barbeque hogs are sold for $0.75/lb of live weight at slaughter. Previous studies have found that various forms of stress on livestock can affect growth and development, and thus the profit of the farm.  The objective of this research was to determine the effect of handling stress on the growth of piglets on the Warren Wilson College farm.  The hypothesis was that handling stress would have an effect on weight gain.  There were 4 sows in the research, and it was a repeated measure design study.  Two litters from each sow, one in February and one in July, were used in this study.  To control for variability among sows, one litter was in the control treatment, and the other the experimental treatment.  The piglets in the control treatment were not handled at any time except for routine husbandry handling.  The piglets in the experimental treatment were handled individual for two-minutes each, three times per week, for seven weeks.  Their mouths were held gently closed. Three weights were collected for each piglet over the seven weeks.  The first weight was collected at one day old, the second at five weeks old, and the third at seven weeks old.  A paired t-test was run on the average weight gain per piglet for each sows control versus experimental litters.  The p-value was 0.49, which suggests there was no significant difference.  A paired t-test was run again, excluding one sow.  She killed all piglets except two in her control litter.  All other litters in the study had between 6-8 piglets.  The p-value for the paired t-test excluding her data was 0.14 suggesting there was no significant difference between the handled piglets and control piglets.  These results suggest no support for the hypothesis that handling stress would effect weight gain.

Scott Steinbrueck
March 31, 2003
A Comparison of Terrestrial and Aquatic Tardigrada
Mentor: Dr. Paul Bartels

Abstract: Tardigrades were first discovered in 1773.  They comprise their own phylum, Tardigrada, which is a sister group of the arthropods.  They are one of the lesser-known phyla.  While over 900 species have been identified, very little is known about their basic ecology.  The objective of my research was to determine if there were any morphological differences between terrestrial and aquatic tardigrades.  It is hoped that this study will suggest possible avenues for future research into adaptations for terrestrial and aquatic living.  Two comparisons were done; one intraspecific, within the species Macrobiotus richtersi, and one interspecific, within the genus Isohypsibius.  Tardigrades were isolated from their habitat and preserved in jars of alcohol.  The jar contents were then placed on a gridded petri dish and organisms were removed with an Irwin loop.  Specimens were mounted onto microscope slides using Hoyer&rsquo;s Medium.  Measurements were taken for body length and width, buccal tube length and width, and claw length.  All measurements were done with an ocular micrometer on a phase-contrast microscope.  Within the intraspecific comparison, significant differences were found in body length (p value = 0.030), body width (p value = 0.029), buccal length (p value = 0.005), and buccal width (p value < 0.0001).  In this comparison, aquatic specimens were smaller than terrestrial specimens.  Within the interspecific comparison, the only significant difference found was in the claw length measurements.  The aquatic species had longer claws than the terrestrial species.  The differences within the intraspecific comparison of Macrobiotus richtersi may exist for two reasons, one functional and one nonfunctional.  The functional reason suggests that aquatic specimens may have been smaller because of adaptations to stream life.  The nonfunctional explanation is that the aquatic specimens may have been collected at an earlier instar stage and were therefore less mature than the terrestrial specimens.  The longer claw length found in the interspecific comparison of Isohypsibius may be an adaptation to help the organisms grip to surfaces in running water.

Arlette Rogers
March 31, 2003
Sex Ratios in Loggerhead Sea Turtles as a Function of Incubation Duration and Dune Temperature
Mentor:  Dr Louis Weber

Abstract: Loggerhead sea turtles (Caretta caretta) are listed as threatened under the Endangered Species Act of 1973 (ESA).  As a result the turtles are federally protected and conservation efforts have been devised to help increase the population.  Sex in sea turtles is determined by temperature during the middle third of incubation.  This phenomenon is known as temperature dependent sex determination (TSD).  Eggs in nature experience a range of temperatures and it is not clear whether the average of a changing temperature produces the same effects as a constant temperature of the same value. This is known as the transitional range of temperature (TRT).  Temperature has two important roles on sea turtle eggs and their development.  Warmer temperatures result in greater percentages of females and shorter incubation durations.  My objective was to first look at the TRT for individual nests laid in the summer of 2001 on South Island, South Carolina and determine if there is a correlation between incubation duration and sex ratios.  I also compared temperatures taken from the flat and the top of a sand dune on South Island to determine whether nest relocation could effect sex determination.  StowAway TidbiT Tempeature Loggers were buried 50 cm below the surface of the sand at six different dune sites on the island.  There were three loggers at each site, one at the flat of the dune, one in the middle, and one at the top.  Temperature readings were taken every 2.5 minutes during the nesting season from May 22 to September 11, 2001.  The average temperature was taken for the second trimester of each nest and plotted in a graph against incubation duration.  It was found that there was no detectable correlation between average second trimester temperature and incubation duration.  I believe this result is an outcome of a short nesting season, a small sample size, and the chaos of the natural world as opposed to a controlled setting.  A distinguishable difference was found in the average temperatures taken from the flat and top of a sand dune.  It is clear that the relocation of nests may have an impact on the sex ratio of loggerhead hatchlings on South Island and should be taken into consideration when assessing conservation efforts for the species.

SarahKeith Valentine
April 7, 2004
Salinity Effects on Microbial Processes within and below the Wetland Rhizosphere
Mentor: Dr. Mark Brenner

Abstract: Three microbial processes dominate carbon metabolism in anaerobic wetland sediments. These processes are iron(III) reduction, sulfate reduction, and methanogenesis.  Each of these processes uses carbon as an energy source, which results in competition for the supply of organic carbon. In the freshwater wetland they studied, Roden and Wetzel (1996) found that the presence of roots enhanced iron(III)-reduction and suppressed methanogenesis.  The objective of this study was to determine if  the findings of Roden and Wetzel (1996) are reproducible in a different wetland system, and also to determine whether their findings will be affected by the presence of sulfate in the system.  This was done by monitoring rates of iron(III) reduction, sulfate reduction and methanogenesis in soil cores taken both below and within the rhizosphere, and from both a saltwater (Jack Bay) and a freshwater (Jug Bay) marsh.  Fe(III) reduction rates were determined using a colorimetric procedure, sulfate reduction rates were determined using a radioisotope, and methanogenesis was measured using a gas chromatograph. The results were compared using a nonparametric paired t-test.  While the general trends for microbial processes found in Jug Bay (fresh) were similar to the freshwater site that Roden and Wetzel studied, statistical analysis showed that there was no significant difference in microbial processes below versus within the rhizosphere for Jug Bay (p-values > 0.31).  There was also no significant effect of roots found in Jack Bay, the saline site (p-values > 0.53). These results suggest that there is a lot more research to be done in this area, examining different factors that affect the importance of the microbial processes in wetland soil.

Savanna S. Cashion
April 14, 2003
Kickboxing and Respiratory Physiology
Mentor: Dr. Victoria Collins

Abstract: Aerobic kickboxing has taken the competitive high-energy moves of competitive martial arts and incorporated them into a functional group workout to fit a variety of fitness goals and capacities.  Aerobic activity trains the heart, lungs, and cardiovascular system to process and deliver oxygen quickly and efficiently to every part of the body.  A goal of many athletes is to improve their ability to catabolize fat for fuel.  By measuring the respiratory quotient (RQ), the ratio of carbon dioxide produced to oxygen consumed, it can be determined when an individual shifts from burning carbohydrates to burning fat.  The RQ of fat is 0.7.  The RQ of a carbohydrate is 1.0.  The amount of ATPs used in ratio to carbon dioxide produced for carbohydrates is 6.3.  It is 8.1 for fat.  If the same amount of ATP is used, a person should produced less carbon dioxide when burning fat than when burning carbohydrates.

This study investigated the respiratory quotient of six women in a kickboxing class for four weeks to determine if the training program offered a successful pathway for bodily fat reduction.  Respiratory gases were collected at the start, middle, and termination of each 1-hour exercise session.  Samples were collected from some subjects 30 minutes after the workout to investigate the post-exercise oxygen consumption.  Oxygen measurements were not reliable.  Carbon dioxide measurements were reasonable and reproducible.  The carbon dioxide output was not significantly different among individuals or sampling periods.  However, average carbon dioxide output over the entire session differed significantly (p<0.05 by Kruskal-Wallis) over the four-week study period.  Average carbon dioxide output decreased significantly during the study, which suggests an improvement in fat catabolism.

Tom Gilfoy
April 14, 2003
The effect of dietary supplementation of red worms (Lumbricus rubellus) on a tilapia (Tilapia nilotica) and sweet basil (Ocimum basilicum) based recirculating hydroponic/ aquaculture system.
Mentor: Dr. Mark Brenner

Abstract: Human beings consume large amounts of aquatic organisms.  This has placed a strain on our ocean&rsquo;s ability to keep up with consumer demands.  Aquaculture presents itself as a viable alternative to traditional fishing tactics, but the feed used in aquaculture production is comprised of ocean bio-mass, thus adding to the problem of over fishing.  In search of a food alternative for the culture of fish and sweet basil in recirculating, aquatic/hydroponic systems, Tilapia nilotica were supplementally fed red worms as opposed to a purely traditional dry feed diet.  There were six systems in all, three of whch were fed 4g of traditional dry feed and three that were fed 2g dry worms and 2g traditional dry feed.  Basil was grown with effluent from the corresponding systems.  After a one-month period of time there was no significant difference in weight gain of Tilapia nilotica fed the different diets with a P-value of 0.3898.  Basil growth for a one-month period with effluent from the two different systems also showed no significant difference with a P-value of 0.4799.  Six aquatic/hydroponic systems were successfully set up in the Warren Wilson College greenhouse.  Because there was no significant difference between the two diets, red worms appear to be a more economically and environmentally viable diet for fish in small-scale aquaculture.


April 28, 2003

Habituation times in the sensitive plant, Mimosa pudica

Mentor: Dr. Jeff Holmes

Abstract: The sensitive plant is so named because of its dramatic thigmonastic response.  When stimulated by heat, wind, rain, or touch it rapidly folds its leaves and collapses its petioles, returning them to their original position after several minutes.  Despite extensive research, M. pudica's methods of stimulus transmission and perception remain unclear.  If stimulated repeatedly, M. pudica will cease to respond to a specific stimulus and begin to re-open its leaves.  This is known as habituation.  It was my objective to determine whether M. pudica&rsquo;s habituation time would change if the plants were habituated every day for seven days.  I showered the plants each day until every one habituated, recording the time it took for each to do so.  I removed one plant for a control, habituating it only on the first and last day, while the others were subjected to the same habituation protocol every day for seven days.  I analyzed my data with a graphical regression test and obtained a p-value of less than 0.0001 and an r-squared value of 0.5435.  There was a significant decrease in habituation time, suggesting that habituation times can be influenced by training or history.  This may have implications for understanding the mechanism of habituation, which has previously been unclear.

Molly Hubbard
April 28, 2003
Midwifery in WNC: A Study of 100 Home Births
Mentor: Dr. Robert Eckstein

Abstract: Midwives have traditionally attended women at birth. There are an estimated 6,000 traditional midwives and 7,000 certified nurse midwives in the US. In North Carolina and 16 other states, the practice of traditional midwifery is illegal .The data was obtained through survey from four traditional midwives and one certified nurse midwife.
The first objective of this study was to determine the frequency of specific complications and interventions for 100 low risk home births attended by five local midwives. The study found the following frequencies: 80% of the babies experienced no complications, 79% of the mothers had no complications in labor, 65% of the mothers had no third stage complications, and 74% of all births had no interventions used during labor.  The total intervention frequencies were as follows: Amnitomy 12%, hospital transfer 9%, vacuum assisted 0%, use of Prostaglandins or Syntocin 9%. The total number of labor complications per 100 births were as follows: delayed rupture of the membranes 6%, prolonged labor-exhaustion 11%, prolapse of the umbilical cord 1%, fetal distress 3%, Meconium staining 14%. The total number of third stage complications per 100 births were as follows: postpartum hemorrhage 8%, retained placenta 5%, and shoulder distochia 8%.  Total complications to the baby per 100 births were as follows: 9% jaundice, 5%transient tachypnea, Meconium aspiration 1%, infant resuscitation 5%, There were no babies that experienced fractures or neonatal infection in the study.

The second objective of this study was to determine if the frequency of these complications and interventions was affected by a midwife&rsquo;s years of experience. The study found a significantly lower use of interventions among midwives with more years of experience as compared to midwives with less years of experience.  There was no association between the frequency of complications and the length of midwifery practice.

Jed Brown
May, 5 2003
Phthalate Metabolites in Copenhagen Waters
Mentor: Dr. John Brock

Abstract: Phthalates are industrial chemicals used in many consumer products.  Recent studies have shown that phthalates disrupt reproductive tract development in the male rat and widespread exposure has been found among adult humans.  Phthalates have been found in every part of the environment and create an urgent need for human exposure assessment studies because of their possible teratogenic, mutagenic, and carcinogenic affects.  The objectives of this study were, to determine and compare MBP and MEHP concentrations in Copenhagen waters and to compare the results of this study to other water studies.  The monoesters were collected through convenience water sampling.  Solid phase extraction was used to concentrate the samples.  Liquid chromatography with coupled mass spectrometry (LC-MS/MS) was used to analyze the samples.  Concentrations of both monoesters were found in all samples sites in Copenhagen.  Untreated waters (i.e. canal, lake) had higher concentrations than treated waters (i.e. tap, bottled, control).  Measuring the pooled monoester concentrations in the surrounding environment allow researchers to estimate the quantities of phthalates being metabolized by organisms.  While little is known about phthalate health effects in humans, this type of research can eventually lead to a better understanding of phthalate exposure.