Natural Science Seminar Abstracts 2005-2006



Sept. 5, 2005
Elizabeth Wunker
Nest-site Selection of the Piping Plover
Mentor: Dr. Louise Weber

Abstract: The Piping Plover (Charadrius melodus) is a small shorebird endemic to North America. These birds nest along the shores of rivers and lakes in the Great Lakes and Great Plains and along the coast and bays of the Atlantic. In New York the piping plover is federally threatened and state endangered. One New York site that has nesting piping plovers is the Incorporated Village of West Hampton Dunes. Currently, the Village is undergoing a 30-year nourishment project in which the Army Corps of Engineers pumps sand onto the beach every five years. Nourishment has raised the question of whether the number of nesting piping plovers can be increased by adding more than just sand to the beaches. The objective of this study was to determine whether piping plovers select nest sites depending on the amount of sand, shell, cobble, and vegetation compared to random sites on three Westhampton Island sites. The study was conducted on Shinnecock beach, Westhampton beach, and the Incorporated Village of West Hampton Dunes between April and July of 2004.   Thirty-two nest and corresponding random points were found and substrate data was collected using a 1 m2 grid with 36 intersections. The substrate under each intersection was recorded. SAS was used to run a multiple logistical regression test on eighteen selected models. Three models were found to be stronger than the null but not significantly (p > 0.05) different from random points. They included (1) percent cover by grass and total large shell (2) percent sand, and (3) total large shell. None of the models were strong enough to recommend the addition of other substrates to the sand during nourishment. I would recommend that the Army Corps of Engineers  maintain their current nourishment methods of laying down just sand.

September 19, 2005
Sarah Zane Lewis
The Role of the Unique Region of the Surrogate Light Chain in Autoimmunity
Mentors: Dr. James Baleja, Dr. B. David Stollar and Dr. Jeffery Holmes

Abstract: Autoimmune diseases are a broad category of systemic illness caused by an immune response to self molecules.  In the case of systemic lupus erythematosous (SLE), disease is marked by the production of anti-DNA antibodies.  The origin of autoreactive antibodies, or autoantibodies, is not fully understood.  Antibodies are produced by plasma B cells, once antigen is encountered via the B cell receptor.  One component of the B cell receptor, the heavy chain, is known to be autoreactive if not accompanied by a light chain.  In a pre-B cell receptor, the surrogate light chain may act in place of the light chain to reduce autoreactivity by the heavy chain.  The surrogate light chain (VpreB) exhibits a non-light-chain-like unique region that has been removed by mutation with little effect.  This raises questions about the purpose of this non-immunoglobulin-like region.  The objective of this study was to determine whether the surrogate light chain (VpreB) affects the autoreactivity of the heavy chain.  A second objective was to determine the extent to which the unique region of surrogate light chain protein, VpreB, plays a role in the binding of ligand.  In this study, the ssDNA, poly(dT), was used as a marker for autoreactivity.  A modified sandwich type ELISA was used to determine the amount of ssDNA bound by VpreB, wild type and mutant, with and without the heavy chain domain, VH19.  Three assays were completed with similar results.  The surrogate light chain was not found to lower the autoreactivity of the heavy chain.  The absorbance of both proteins increased when incubated together as the pre-B cell receptor complex.  Additionally, the surrogate light chain mutant, VpreBDU-J, was found to have an absorbance greater than the heavy chain alone.  This suggests that the surrogate light chain may not play a role in inhibiting ligand binding by the heavy chain.  The data also suggest that the unique region has an inhibitory function, previously undiscovered.  Further study could determine whether the unique region inhibits the binding of self molecules, reducing the autoreactivity of the heavy chain at the early pre-B cell stage.  Continued study of the unique region and the potential relationship to autoreactivity will broaden current understanding of the function of the surrogate light chain and the role of the pre-B cell receptor in development and autoimmune disease.

September 19, 2005
Erik Nash
The relationship between Vicia sativa and the ants feeding at their extrafloral nectaries on the Warren Wilson campus.
Mentor: Dr. Amy Boyd
   
Abstract: Vicia sativa, a pea like annual, native to the United Kingdom is found all around the Warren Wilson Campus from early April to late May.  This plant has nectar-secreting organs, called extrafloral nectaries (efns), located on the underside of each stipule. It has been noticed that an unusually large number of ants are living on or near by the V. sativa plants.  Ants and plants are known to form symbiotic mutualisms in which the ant receives nectar from the efns and the plant receives protection from the ant.  A symbiotic mutualism is defined as a relationship in which two species, living in close proximity to one another, both benefit from their relationship.  The objective of this study was to determine if a symbiotic mutualism existed between V. sativa and the ants found feeding at their efns on the Warren Wilson’s campus.  In order to determine this, the efns of all my experimental plants were cut off so nectar was no longer secreted, while the control plants remained unharmed.  At least twice a week the plants were inspected, treatments were carried out and the number of ants on both the control and experimental plants were recorded.  After a month of treatments a blind research assistant was used in order to judge the relative amount of herbivory received by each plant.  After comparing the relative amount of herbaceous damage received by the control plants (n=23) and the experimental plants (n=23) I used the Mann-Whitney test to conclude that the presence of efns did not affect the amount of herbivory a plant received (p=0.0966).  The amount of ants found on each of the control plants and the experimental plants were compared using the Mann-Whitney test to see if the presence of efns affected ant numbers.  I found a significantly larger number of ants (p=0.0007) on the control plants then on the experimental plants.  Finally, a linear regression test was performed to see if there was any correlation between the amount of ants found on each plant and the herbivory scale number that plant received.  Because there was no correlation between the numbers of ants found on the plants and the herbivory scale ratings the plants received (p=0.2920), I concluded that there was not a symbiotic mutualism between V. sativa and the ants feeding at their extra floral nectaries on the Warren Wilson campus.


September 26th, 2005
Audrey Williamson
The Effects of Age and Gender on the Learning Ability of the Horse (Equus caballus)
Mentor: Dr. Robert Eckstein

Abstract: Horse training is a valuable industry within the United States and throughout the world.  In order to capitalize on this industry it is important to understand the horse (Equus caballus) and it’s natural tendencies.  Horses have evolved to thrive on the open plains and have dichromatic color vision.  The objective of this study was to measure the effect of age and gender on the ability of a horse to successfully complete a learning task.  The learning task was to discover and remember that the white bucket has accessible food.  Each horse was led into a standard pen and allowed to choose between a black bucket and white bucket.  The horse was positively reinforced for choosing the white bucket; the black bucket was a neutral stimulus.  Neither gender (p value= 0.9695) nor age (r=0.0035) were found to have a significant effect on the learning ability of the horses tested. All horses were successful in completing the learning task, suggesting that horses of various ages and genders can be successful at learning through operant conditioning.



September 26, 2005
Josha McBee
Determination of Paw Preference in Raccoons (Procyon lotor)
Mentor: Dr. Robert Eckstein

Abstract: Raccoons (Procyon lotor) have sensitive, agile hands, which they use to handle prey, climb, and pry things open.  Their highly developed tactile sense made them a good subject for a paw preference study.  Paw preference is defined as the tendency to use one paw over the other.  There have been many studies done on paw preference dating as far back as 1930.  These studies have primarily investigated chimpanzees, rats, mice, cats, and dogs.  Results of these studies have found paw preferences to exist in individuals of all these species.  My objective was to determine whether individual raccoons show a paw preference in a food/toy-reaching task.  This task required the raccoons to reach a paw through a small opening in a container in order to pull out food or a toy.  My hypothesis was that the raccoons would use one paw more than the other when reaching into the container.  I tested six raccoons at Genesis Wildlife Sanctuary on Beech Mountain N.C.  I recorded which paw each raccoon used to reach into the container for a total of 100 reaches.  I ran a chi square test for each raccoon individually.  The resulting p-values for all six raccoons were less than .02.  This supports the hypothesis that all six raccoons have a paw preference.  


October 3, 2005
Clayton Wilburn
Analysis of Synthetic and Natural Estrogens in the Influent and Effluent of the Buncombe County Wastewater Treatment Plant
Mentor: Dr. John Brock

Abstract: In recent years researchers have become increasingly concerned with the presence of endocrine disrupting chemicals (EDCs) in the environment. The majority of the research on EDCs focuses on estrogen mimics, which primarily enter the environment from sewage treatment plant effluent. The natural estrogens estradiol and estrone and the synthetic estrogen ethynylestradiol are principally responsible for the estrogenic nature of wastewater and are known to cause feminization of male fish at low parts per trillion (ppt) concentrations. Therefore the objective of this study was to quantify the amount of estrone, estradiol, and ethynylestradiol in the influent and effluent of the Buncombe Co. wastewater treatment plant and determine the elimination of the analytes from the influent. Isotope-dilution gas chromatography/mass spectrometry (GC/MS) served as the method of analysis. The analytes were derivatized using BSTFA with 1% TMCS in pyridine. For the initial calibration curves a linear response over two orders of magnitude was obtained for estradiol and estrone but not for ethynylestradiol. The label ethynylestradiol was found to be contributing to the native signal after performing a full scan analysis. A linear response was obtained for ethynylestradiol when the quantitative ions were changed. The analytes were extracted from the wastewater samples using solid-phase extraction. In the preliminary analysis of wastewater samples, the target analyte peaks were inadequately separated from co-eluting peaks. The GC column was changed to a 60 m column, and the wastewater samples re-analyzed. The longer column achieved adequate separation of the target analyte peaks. Calibration curves were then constructed using the new column, and the limit of detection (LOD) for each analyte was determined. The instrument LOD for estradiol and ethynylestradiol was 31.9 ppb and 13.4 ppb, respectively. The method LOD for estradiol and ethynylestradiol was 6.38 ppt and 2.69 ppt, respectively. Estrone was eliminated from the analysis due to interference in the method. The concentration of estradiol in the influent and effluent was determined to be <6.38-<16.0 ppt, with the variation due to different sample size. The concentration of ethynylestradiol in the influent and effluent was determined to be <2.69-<6.70 ppt, with the variation due to different sample size. The obtained concentrations agree with the concentrations of estradiol and ethynylestradiol found in other studies. Further analysis of the wastewater is warranted, as the concentrations of estradiol and ethynylestradiol found in this study are in the hormones’ effective range for endocrine disruption in wildlife.


October 3, 2005
Emily Leghart
Relationships between body length and attributes of vocalization in Gray Tree Frogs.
Mentors: Dr. Robert Eckstein and Dr. Paul Bartels
   
Abstract: There are two species of gray tree frogs: Hyla versicolor commonly called the Gray Tree Frog, and Hyla chrysoscelis referred to as Cope’s Gray Tree Frog. Although Hyla versicolor and Hyla chrysoscelis are two separate species they used to be considered the same species because they are cryptic.  In the field, the only way to differentiate the frogs is by vocalization.  The call of Hyla chrysoscelis is a faster trill and has a higher pitch than that of Hyla versicolor.  The collective range of the gray tree frogs’ is from Maine and southeastern Canada to Northern Florida and from the east coast to as far west as Central Texas.  The most commonly heard frog calls are advertisement calls of males.  This type of call is primarily used to attract females or to defend or gain mating territory.  A female may be attracted to different aspects of a male’s call.  The specific properties or combination of properties that actually attracts the female is species specific.  The objective of my study was to determine whether the length of individual frogs played a role in the latency between its calls, number of trills per call, and frequency at peak intensity of trills. I also wanted to determine if the species of frogs from the population I sampled were Hyla chrysoscelis or Hyla versicolor.  To do this I sampled gray tree frogs from the Warren Wilson Pig Pond over a three-week period this past summer during the frogs’ mating season.   To collect my samples I located the frogs by sound then by sight.  I would then record the individuals’ calls on a Marantz Portable Cassette Recorder using a Dan Gibson Parabolic Microphone.  I assigned each frog a letter and recorded the temperature.  I then caught the frogs by hand.  I measured the frog from the snout to the caudal end.  I released the frog as close to the collection site as possible and moved further along the pond to continue sampling.  I collected between five and eight calls from 12 frogs to analyze for a relationship between the body length and vocal attributes.  I recorded 13 additional calls from non-captured individuals to analyze for a relationship between the temperature and the trills per second.  All 25 sets of calls were used in the species analysis.  The calls were analyzed using the audio editing computer program Raven Lite from Cornell University.  I analyzed the calls for the average number of trills per call, average latency between the calls, and average frequency at peak intensity.  I used a linear regression analysis to determine if the length of the individuals affected the average latency between the calls, average number of trills per call, and average frequency at peak intensity of trills.  I found no significant correlation between body length and any of the analyzed vocal attributes.  I compared my sampled calls with previous studies, which compared the vocalizations of the two species of gray tree frogs.  The results of this species analysis were inconclusive. 

November 7, 2005
Bart Pfautz
The Effect of Leachate from Wood Shavings Produced in Trail Maintenance on Daphnia magna.
Mentor: Dr. Greg Ettl

Abstract: Wooden poles are often used in trail projects throughout the U.S. National Park system.  In the Great Smoky Mountains National Park chromated copper arsenate treated poles, untreated black locust (Robinia pseudoacacia) poles, and untreated eastern hemlock (Tsuga canadensis) poles are the most commonly used.  These poles are used because they are decay resistant.  The most significant cause of decay in wood is fungi.  Wood-destroying fungi can seriously reduce the service life of wood.  Extractives are the compounds primarily responsible for a wood’s natural resistance to decay.  They are toxic to decay organisms.  Extractives are easily leached from wood with water.  Woods that are not decay resistant are treated with preservatives that are toxic.  Chromated copper arsenate has been the most widely used preservative for the past 60 years.  Recently the EPA has banned the use of CCA-treated wood for residential purposes due to the toxicity of the CCA preservative components.  Leachate from CCA-treated wood is toxic to a variety of marine organisms.  Some studies have suggested that untreated wood is more toxic than treated wood.  The proposed reason is that naturally occurring extractives are removed or altered in the CCA treatment process and are no longer toxic.  The objective of my study was to determine the relative toxicities of the three woods used for trail projects in the Great Smoky Mountains National Park.  A sample composed of saw chips from fifteen different poles was made for each treatment – CCA-treated wood, hemlock, and black locust.  Leachates were produced using each composite sample.  Daphnia magna mortality in each of the leachates was recorded over a two-day period.  A contingency table was used to perform a chi-square test on the data.  At one and a half hours of exposure significant mortality was seen in the CCA-treated wood leachate (p<0.05).  After a day of exposure significant mortality was seen in all the treatments.  In a CCA-treated wood leachate, produced from one-tenth the amount of wood used to produce a hemlock and locust leachate, significant mortality was reached earlier.  CCA-treated wood leachate was more toxic to Daphnia magna than hemlock or locust leachates.


November 7, 2005
Amos Little
Herbicidal effects of Ailanthus altissima extracts on native and non-native invasive plants
Mentor: Dr. Michael Torres

Abstract: This country spends approximately 137 billion dollars a year in efforts to control introduced species, also known as exotics. Thirty-four billion of the 137 billion dollars is spent in efforts to control exotic plants. One reason that some exotics do so well in introduced environments is thought to be because some produce chemical compounds that inhibit the growth and germination of other plants; this is called allelopathy. One of the exotics on Warren Wilson College campus that has been a problem in that past is Ailanthus altissima (Tree-of-Heaven), which has been shown to produce allelopathic compounds. The objectives of this study were to determine if aqueous extracts of A. altissima inhibited the growth and/or germination of native and non-native invasive plants. Three species where used in this experiment: Robinia pseudoacacia, Celastrus orbiculatus, and Lespedeza bicolor. All three species were tested in two studies: a survival study and a germination study. Three treatments were applied to all three species in both treatments: a control of D.I. water, a low concentration (4g/L) and a high concentration (10g/L). The extracts where made from dry A. altissima root bark by soaking 10g or dry bark in 1 liter of D.I. water for 48 hours with occasional agitation; the low concentration was made by diluting the high concentration down to 4g/L.  In the survival study there were 10 replicates per concentration per species; each replicate was an individual plant in a pot with soil media. 30 ml of the extracts (control, low or high) where applied three times at intervals of four days in between each application. At the end of the application period the plants were classified as dead or alive (if the plant had low vigor but leaves not completely bleached it was considered alive). The germination study had 3 replicates per concentration per species; each replicate was a petri dish with Whatman paper and 20 seeds in it as well as the respective concentration (control, low or high). The seeds were allowed 10 days to germinate and at the end of the 10 days the number of germinated seeds were counted. A Chi-Squared contingency table was used to analyze the survival study data and an ANOVA test was used to analyze the germination study data. The p values for the survival studies were: 0.0039 for L. bicolor, 0.014 for R. pseudoacacia, and 0.029 for C. orbiculatus. In all three cases there was a significant difference between the survival rate of the plants in the control group and those in the high concentration group. The p values for the germination studies were: 0.0001 for L. bicolor, 0.0002 for R. pseudoacacia, and 0.0014 for C. orbiculatus. There was a significant difference between the germination rates of the seeds in the control vs. low, control vs. high, and the low vs. high concentrations in all three species. The significance in each study shows that the Natural Resources Crew on Warren Wilson College campus could potentially use A. altissima extracts as an herbicide to control other exotics but further studies need to be concluded to be sure.



November 21, 2005
Tessa Branson
The Determination of Vitamin B-12 Deficiency on WWC campus in vegans vs. non-vegans.
Mentor: Dr. Victoria Collins

Abstract: Vitamin B-12 (Cobalamin) functions as a coenzyme for many important biochemical processes including the synthesis of DNA and red blood cells and the breakdown of amino and fatty acids.  Vitamin B-12 is obtained primarily from animal proteins (ie, red meat, poultry, fish, eggs, and dairy).  Plants and vegetables lack this vitamin unless they have been exposed to microorganisms.  Vegans, due to the lack of animal proteins in their diet, are susceptible to a B-12 deficiency.  B-12 deficiency has been documented in several populations worldwide and has serious health implications including: physical weakness, irritability, neurological depression, and dementia.  The popularity of the vegan-vegetarian diet at WWC is a cause for concern, as B-12 deficiency is a potential campus health issue. The objectives of this experiment were to (a) develop a non-invasive method to monitor B-12 status and (b) to compare B-12 levels for vegetarians and omnivores at WWC.   Cobalamin status can be measured indirectly from urinary levels of methylmalonic acid (MMA).  If the level of vitamin B-12 in the body is adequate, MMA is converted to succinate, and then metabolized.  If the level of vitamin B-12 is inadequate, MMA accumulates and is excreted in the urine.  This study used GC/MS to identify and quantify urinary MMA.  Gas chromatographic analysis of MMA requires the conversion of MMA to a volatile derivative.  The derivatives are chromatographed and quantified by comparison to an internal standard, MMA-d3.  Two different volatile derivatives, tri methyl silyl esters and methyl esters, were prepared.  The chromatograms of the trimethylsilyl esters were not reproducible.  Methyl ester derivatives could be quantified to a detection limit of about 3 micrograms/ml in solutions of pure MMA.  Dried urine samples showed MMA concentrations below 3 micrograms/ml.   Pretreatment methods for urine samples must be perfected before sample collection.  After analysis procedures have been verified, vitamin B-12 status of Warren Wilson students can be assessed.

November 28, 2005
Alana Weintraub
Natural and Biological Control Methods of Reducing Mealybug Infestations in the Warren Wilson College Research Greenhouse.
Mentor: Dr. Amy Boyd.

Abstract: Mealybugs are common pests with immense economic importance, as they feed on the sap of agricultural crops, interior landscapes, and greenhouse plants worldwide.   The female mealybugs have piercing mouthparts that enable them to suck sap and feed on a wide range of host plants.  Removing sap causes a multitude of damage to the plant, and spreads pathogens and viruses from plant to plant. A waste-product is produced by the mealybug, called honeydew, that coats plants and serves as a medium for black fungal growth, which weakens and kills plants.  Male and female mealybugs differ in appearance and life cycles. Several published treatments to control the infestation of citrus mealybugs include:  rubbing alcohol, Malathion, Insecticidal Soap, pheromonal lures, and biological control agents.  The published biological control agents used to control citrus mealybug infestations include:  Cryptolaemus montrouzieri, Entomophtora fumosa, and Leptomastix abnormis.  The objective of this study was to determine whether the biological method of introducing the predator ladybeetle Cryptolaemus montrouzieri or the current method of spraying M-pede insecticidal soap would better eradicate the citrus mealybug infestation from the Warren Wilson College Research Greenhouse.  In this study, 24 Coleus plants were infested and placed within a large observation cage lined with special screening that prevented the immigration and emigration of larvae and biological control agents.  The plants were separated into three treatment groups:  control, insecticidal soap spray, and release of Cryptolaemus montrouzieri.  The individual plants of the control and spray groups were placed within miniature cages, but the plants of the biological control group were not, which allowed the biological control agents freedom to fly about the large cage.  Data collection involved taking initial and final counts of the populations of both adult and instar-staged citrus mealybugs for two months.  The population changes of the three treatment groups for both adult and instar-staged mealybugs were subjected to ANOVA, the statistical analysis of variance.  The p-value for the population change of adult citrus mealybugs during month one was 0.2038, which is considered not significant.  The p-value for the population change of instar-staged citrus mealybugs during month one was 0.2326, which is considered not significant.  The p-value for the population change of adult citrus mealybugs during month two was 0.0912, which is considered not quite significant at the 0.05-level.  The p-value for the population change of instar-staged citrus mealybugs during month two was 0.0012, which is considered very significant.  The only data subjected to Tukey-Kramer Multiple Comparison tests were the population changes of the instar-staged citrus mealybugs during month two, because it was the only significantly different data group.  The Cryptolaemus montrouzieri and the insecticidal soap treatment groups differed significantly, with p<0.01; C. montrouzieri and the control treatment groups did not differ significantly, with p>0.05; and the insecticidal soap and the control groups differed significantly, with p<0.01.  Potential sources of error and experimental errors may have contributed to the results of the C. montrouzieri treatment groups, in which the population changes of adult and instar-staged mealybugs decreased during the first month, yet the adult population of mealybugs increased during the second month.  These errors include counting errors, as well as the technique error of the biological control agents escaping. 

January 30, 2006
Paul Bailey
Bird Diversity on Warren Wilson College Campus
Mentor: Dr. Lou Weber

Abstract: In the fall of 2005 Warren Wilson College cut a 0.5 acre stand of white pine (Pinus strobus) on Christmas Tree Hill to plant native grasses and provide early successional bird species habitat. This followed a study in the spring of 2002 in which Fletcher compared winter bird diversity at North Lane and Pumphouse Stand. The North Lane site had a complete overstory removal in 2000 by Warren Wilson College because of a southern pine beetle (Dendroctonus frontalis) outbreak. The Pumphouse Stand was a dominant white pine site with continuous canopy. Fletcher found the North Lane clearing to have a considerably higher number of bird species than Pumphouse Stand. More recently, the Pumphouse Stand has been thinned by Warren Wilson College to bring more light through the canopy to allow for propagation of other tree species. My objectives were to compare North Lane bird diversity to the Wildlife Plot and Pumphouse Stand, and also to Fletcher’s 2002 data. I also intend to suggest management implications for bird habitat on Warren Wilson College campus. I recorded bird diversity at each site from August 2005 through October 2005. I made five observations at each site during this period for a total of fifteen observation dates. Observations were done at dusk, during the evening chorus. I counted a total of seventeen bird species from three sites. Fifteen of the species were present in the Wildlife Plot, fourteen in North Lane, and nine at Pumphouse Stand. This suggests that bird populations on Warren Wilson College campus prefer small forest openings to pine stands. About 5.8 (0.98%) of 640 acres of Warren Wilson College forest is open canopy (10 years old). Only 0.5 acres were cut for the purpose of wildlife habitat. I suggest Warren Wilson College manages for more diverse forest stratification for wildlife habitat.

 


January 30, 2006
Katherine Kennedy
Serum Mineral Levels in Piglets on the Warren Wilson College Farm
Mentor: Dr. Jeff Holmes

Abstract: The objective of this study is to compare serum mineral concentrations and average daily weight gain of piglets raised on pasture to those of piglets raised in a barn.  The litters of three sows were placed in each treatment group.  Blood was drawn and weights were taken from each piglet at one, ten, and twenty eight days of age.  The serum from each blood sample was analyzed by inductively coupled plasma optical emission spectrometry for iron, calcium, copper, magnesium, manganese, and zinc.  Results were analyzed using unpaired t-tests with Welch corrections when necessary.  Iron showed a not quite significant difference between treatment groups at one and ten days (p = 0.0858, p = 0.0772) and a significant difference at twenty-eight days (p = 0.0462), with outdoor piglets showing higher concentrations.  Calcium showed a not quite significant difference at twenty-eight days (p = 0.0673).  Copper showed a not quite significant difference at twenty-eight days (p = 0.0843).  Average daily gain showed a significant difference between treatment groups (p = 0.0219).  Calcium, copper, and average daily gain showed higher levels of minerals and greater weight gain in the indoor piglets than the outdoor piglets.  All other minerals showed no significant difference between treatment groups (p > 0.05).  The observed differences in iron levels are possibly due to soil access.  The observed calcium, copper, and weight gain differences between treatment groups are possibly due to differences in access to sow feed, parasite pressure, or exposure to the elements.  The results of this study do support the hypothesis that pasture raised piglets can gain iron from soil access.  However, the results do not support the same hypothesis for all other minerals under consideration or for average daily weight gain.



February 13, 2006Raccoon in cage
Melissa Fellin
Object Handling Behavior in Captive Raccoons (Procyon lotor).
Mentor: Dr. Robert Eckstein

Abstract: 

For centuries, naturalists have claimed that raccoons possess a high degree of cleanliness when handling and consuming their food. This notion of object handling behavior is reflected in the name raccoon, which means that they scratch with their hands. Because of this belief, many regard food handling as a necessary habit to be performed by the raccoons each time an object is grasped. My objective was to determine if the object handling behavior of the raccoons changed when they were tested as individuals and within a group. For my study I used thirteen raccoons that were each presented with eight different objects, where duration of object handling and number of dunks were recorded. When comparing the individual and group trials of all the raccoons, it was found that there was no significant difference (P=0.112) in the object handling times. There was a significant difference (P=0.001) in the handling time among objects ranging from ice cubes handled the longest (265.4 sec) to pinecones handled the least (69.6 sec). After comparing the individual and group handling times of the objects, there was no significant difference (P=0.207 and P=0.458) between when they were alone compared to when they were in groups. My conclusion is that whether raccoons are housed as individuals or in groups the types of objects placed within their environments are what wildlife centers should focus on.

(Photo by Melissa Fellin).

Feb. 13, 2006
Maryka Lier
Percent Cover and survival Rate of Warm Season Grasses
Mentor: Dr. Greg Ettl

Abstract:
Native warm season grasses (NWSG) provide a unique cover type to this area. Although rare on the landscape in the Southern Appalachian Mountain Region, they are found in forest gaps and grassy balds and contribute to the vegetation diversity. Once maintained through anthropogenic fire, the grassy gaps are disappearing. In the fall 2004, a 0.2 ha gap was cut in the White Pine forest of the Fortune property The Warren Wilson Wildlife Gap was created in an effort to restore native grassland and provide habitat for wildlife. The objective of this study was to determine the extent of the establishment of warm season grass within the Wildlife Gap over the first growing season. In spring 2005, the gap was sprayed with herbicide, burned, and 100 1.5 square-meter plots were set up. A mix of 24 grass plugs was planted within the plots and allowed to grow over the summer. For this study I randomly chose 35 plots to sample. Using a quadrat, I measured the percent cover of NWSG relative to percent cover of other woody and herbaceous vegetation. I also measured the survival rate of Broomsedge (Andropogon virginicus), Purpletop (Tridens flavus), Purple Love Grass (Eragrostis spectabilis), Little Bluestem (Schizachyrium scoparium), and Indiangrass (Sorghastrum nutans). Correlation analysis showed a negative relationship between NWSG cover and tree species cover (r=-0.31, p= 0.070), NWSG cover and shrub/herbaceous cover (r=-0.43, p=0.012), and NWSG cover and tree/shrub/herbaceous cover (r=-0.52, p=0.0015). A Kruskal-Wallis Nonparameteric test and a post-hoc multiple comparisons test, showed a difference in mean survival rate among species (p= 0.0025) with a significant difference between the survival rates of Purpletop and Broomsedge (p<0.01), and Purpletop and Purple Lovegrass (p<0.05). The negative correlation of NWSG relative to other vegetation indicates a need for weeding, burning, and herbiciding to cut back competition to NWSG. The survival rate of Purpletop was significantly different from other species but I believe that it should still be included in other restoration projects because of its aesthetic appeal, as well as to encourage diversity. Grass establishment within the first year was a success with 61% of the grass plugs surviving and 26% grass cover.

February 27, 2006
Julia York
The Antiviral Effects of Thirteen Botanical Essential Oils on Three Phages of E. coli
Mentor: Dr. Jeff Holmes

Abstract: Essential oils are volatile oils isolated from non-woody plant material that have been proposed to possess medicinal properties.  Although the use of essential oils has gained popularity as an alternative healing modality, the practice is not widely accepted by the medical community.  Little research has been conducted on the antiviral effects of essential oils.  The objective of this study was to determine the in vitro antiviral effects of thirteen essential oils on three bacteriophages of Escherichia coli.  Bacteriophages are similar to mammalian viruses, but are easier to cultivate and manipulate in laboratory experiments.  Each essential oil was incubated with concentrated phage stock for twenty-four hours, and viral plaque formation was assessed using a plaque formation assay.  Phage and bacteria were plated at two dilutions, ~10-3 and 10-5.  Three aliquots of each dilution were plated.  As a control, phages were separately treated with mineral oil and dilution buffer.  The average plaque number per treatment was divided by the average plaque number per control to derive the percent plaque reduction.  Six of thirteen oils (46%) exhibited a plaque reduction greater than 90% for both dilutions of T2 phage, seven of thirteen oils (54%) exhibited a plaque reduction greater than 90% for both dilutions of T4 phage, and three of thirteen oils (23%) exhibited a plaque reduction greater than 90% for both dilutions of fX174 phage.  Eight oils (62%) inactivated at least one phage.  Although the oils did not affect each phage equally, the active oils tended to inhibit multiple phages, suggesting a general, rather than phage-specific, mode of action.  Essential oils can possess strong antiviral effects, suggesting they may have potential use in clinical practice.

February 27, 2006
Amanda J. Davis
Water quality assessment of the Swannanoa River using macroinvertebrates.
Mentor: Dr. Lou Weber 

Abstract: The Swannanoa River flows through the Warren Wilson College campus and is a part of the French Broad River Watershed in western North Carolina. The North Carolina Division of Water Quality performed its most recent study on the Swannanoa in 2002, which indicated fair water quality. In 2003, a manufacturing plant near the river burned and in 2004 hurricanes Ivan and Frances caused severe flooding.  Macroinvertebrates are used in water testing because they provide a rating for long-term quality based on tolerance to pollutants. I used the North Carolina Biotic Index (NCBI) to determine water quality. My objectives were to determine overall water quality of the Swannanoa, compare the current rating to past studies, examine community composition, and to determine if Warren Wilson College affects water quality. Kick net samples were taken three times in August-September 2005 from three campus locations. Specimens were preserved in ethanol and identified to the lowest possible taxon. The overall NCBI rating was 5.54, indicating good-fair water quality and an increase from the 2002 rating. There was no significant difference between ratings from upstream to downstream (p= 0.208), meaning Warren Wilson has no effect on water quality. The Shannon diversity index was used to determine species richness and evenness. The dominant species at nearly all sites were caddisflies, resulting in little species evenness. Water quality did not decline long-term after the fire and floods, showing the ability of a natural ecosystem to recover after damaging events.


March 6, 2006
Andrew Morin
Arsenic Levels in the Warren Wilson Alpine Tower and the Surrounding Substrate
Mentor: Dr. John Brock

Abstract: Arsenic has been used in wood preservatives for over 70 years (Stilwell 2005).  It is effective pesticide but has negative health impacts on humans, including skin, liver and bladder cancer (EPA 1999).  The Warren Wilson Alpine Tower was constructed in the summer of 2001 as a donation from Alpine Towers International.  The wood preservative used to treat the lumber was chromated copper arsenate (CCA), which is standard in the pole industry (Zartman personal communication).  Sampling methods were based on EPA protocols (2001) with modifications to determine the amount of leaching into the soil under the Alpine Tower.  Soil and buffering material (mulch) samples were taken from below the midpoint of horizontal supports and 5 cm inside of vertical supports.  Samples were taken from the top layer of substrate, between 6-8 cm deep, and between 14-16 cm deep.  .  Results showed arsenic levels ranging from 63.4 parts per billion (ppb) to 124.5 ppb for top-level samples, and from below detection limits to 87.9 ppb for 15cm deep soil samples.  There was a significant variation between samples taken from the top layer and 14-16cm deep, with a p-value < 0.05.  An excess of control samples were taken from a variety of sites around campus, and a random number generator were used to select control samples for analysis.  All control samples had arsenic levels below the limits of detection.  Wood samples were also taken from the tower itself, in locations directly above soil samples, and showed levels of arsenic to 573ppb.  Though the soil samples showed levels of arsenic above most state cleanup levels, it is ill advised to attempt any mitigation besides the best management practices already in use by the Warren Wilson Outdoor Leadership Program.  These practices include coating the tower with a sealant every one to two years, and advising participants to wash hands before eating.  Further research is needed to clarify problems with the matrix modifier.  Additional experiments are requirement to determine the amount of arsenic leached from the tower onto participants’ hands, as well as the amount absorbed through the skin.


March 6, 2006
Emilie Erich
Phytoextraction of Copper and Lead by Sagittaria graminea and Pontederia cordata in Beaver Lake Stormwater Wetland
Mentors: Dr. Mark Brenner and Dr. John Brock

Abstract:  Constructed wetlands can improve water quality through several mechanisms including plant uptake.  Beaver Lake Stormwater Wetland (BLSW), a constructed wetland currently receiving urban runoff from 60 acres of Asheville, NC, was designed to trap sediment and reduce nutrients and inorganic contaminates such as metals.  Water quality data from the BLSW outflow consistently indicates the presence of Cu and Pb in the wetland outflow.  The uptake and translocation of inorganic contaminates is known as phytoextraction, and results in the accumulation of inorganic contaminates in the shoots.  It is a possibility that the vegetation present in BLSW may be phytoextracting Cu and Pb.  The most predominant native wetland plant species are Pickerelweed (Pontederia cordata) and Grassleaf arrowhead (Sagittaria graminea).  The objective of my study was to determine if the Grassleaf arrowhead and Pickerelweed in BLSW were phytoextracting Cu and Pb, and to compare the concentrations of Cu and Pb in Pickerelweed with the concentration of Cu and Pb in Grassleaf arrowhead.  The samples from each species in the wetland were obtained through systematic sampling.  Greenhouse raised individuals from each species were used as a control group for each species to show baseline levels of Cu and Pb in plants grown in a relatively contaminate-free environment.  All samples were analyzed with graphite furnace atomic absorption spectrophotometry following standard analytical methods.  External calibration curves were used to determine the unknown concentration of Cu and Pb in each sample, and the sample results were used to calculate the mean concentration of Cu and Pb in the dry leaf.  The mean concentration of Cu in Pickerelweed leaf was 4.8 ppm in BLSW plants and 8.6 ppm in the controls.  The mean concentration of Cu in Grassleaf arrowhead leaf was 5.7 ppm in BLSW plants and 63 ppm in the controls.  The mean concentration of Pb in the Pickerelweed leaf was 0.014 ppm BLSW plants and 0.057 ppm in control plants.  There was no significant difference between the mean concentration of Cu in Pickerelweed and Grassleaf arrowhead leaves from BLSW (p > 0.05).  There was a significant difference in the mean concentration of Pb in Pickerelweed and Grassleaf arrowhead leaves from BLSW (p < 0.05).  The control results showed unexpectedly high levels of each metal with considerable variability in each control group.  These control results are likely due to contamination and a change in chemical environment.  The results for the BLSW sample groups show that Pickerelweed and Grassleaf arrowhead phytoextracted Cu and Pb from BLSW, and that the concentration of lead in Grassleaf arrowhead leaves was significantly higher than that in the Grassleaf arrowhead leaves from BLSW.  Though Pickerelweed and Grassleaf arrowhead phytoextracted both Cu and Pb from BLSW, the levels of metal accumulation were much lower than those of hyperaccumulators, indicating that neither species is likely to contribute substantially to the reduction of Cu and Pb in BLSW.     

March 20, 2006
Kantesh Dodwani
RecyclingPolypropylene by Pyrolysis.
Mentor: Dr. Dean Kahl

Abstract: This research project was designed to determine whether polypropylene (plastic # 5) could be converted into useful chemical feedstock or fuel using relatively simple technolgy.  In the United States, 23 million tons of plastics are disposed as waste each year. Approximately 14% of plastic wastes are recycled yearly. Plastics are recognized by numbers 1 to 7. Plastic number 1 is most recyclable and number 7 is least recyclable. The objectives of study were (a) to determine if polypropylene could pyrolyzed, (b) to determine the identity of pyrolysis products and (c) to determine if pyrolysis products could be used for fuel or chemical feedstock.  Plastic # 5 (polypropylene) was collected from Warren Wilson recycling center. Using vacuum distillation, the polypropylene was pyrolyzed. Vacuum distillation removes air from the system to prevent combustion. The vacuum made it possible to collect the pyrolysis products. The experiments were done with catalyst (aluminum) and without catalyst. The distilled product was analyzed using several instrumental techniques: GC, IR, and NMR. The results suggested the product was mixture of 18 – 22 different compounds. These compounds were a mixture of alkanes and alkenes. A mass balance analysis shows that variable amounts of gases, liquids and solid residue were produced. The energy balance suggests that the energy required for pyrolysis is higher than the energy available in the distillate.  However, the energy efficiency could be improved and conversion of the distillate to chemical feedstock could make the process economically viable.



March 20, 2006
Murugan Vinayagam
Dynamic Tunneling in a Quantum Mechanical System
Mentors: Dr. Donald F. Collins and Dr. Evan Wantland

Abstract: Quantum tunneling is a phenomenon of a particle existing in classically forbidden regions. Tunneling of quantum particles plays a major role in Scanning Tunneling Microscopy, Quantum Dots, Tunnel Diodes, and Very Large Scale Integrated Systems. Solutions to the Schrödinger equation are studied for a particle-in-a-box with a finite barrier in the center. All the solutions to the Schrödinger equation must be continuous and must satisfy the boundary conditions of zero value at the hard walls. These conditions lead to quantization. We chose to approximate the solutions numerically in order to simplify the process of finding solutions for various types of barriers. A search algorithm was programmed in MATLAB to approximate numerical solutions for the wave functions. The numerical solutions obtained from the search algorithm represent various stationary states of a wave function. Dynamic tunneling is shown by the time-dependence of the superposition of two stationary states. An animation is produced.


Megan Bryan
March 27, 2006
A Demographic Study of Kemps Ridley (Lepidochelys kempii) and Green (Chelonia mydas) Sea Turtle Strandings
Mentor: Dr. Lou Weber

Abstract: For many thousands of years sea turtles have made the ocean their home. The Iroquois nation credits a giant sea turtle with having brought the first humans to land and thus creating the world as we know it. In recent history, however, all species of sea turtles have experienced a drastic decline in population numbers, largely an effect of human-related activities. This study focuses on only two of the six species currently found in U.S. waters: the Kemps Ridley (Lepidochelys kempii) and Green sea (Chelonia mydas) turtles. Using stranding data taken from various South Carolina beaches from the period of 1980 to 2004, the objectives for this study are to (1) analyze the data for mortality patterns for each species in order to determine the sources of mortality present along the SC coast and (2) to detect population changes over time and use these changes to make a statement about the effectiveness of current conservation efforts. The stranding data for each species was provided by the South Carolina Department of Natural Resources and was collected by trained volunteers and SCDNR staff. Patterns in the data indicate that the population of Kemps Ridley turtles has been steadily increasing since 1980. In addition, the observed mortality for both species is significantly higher from 1993-2004 compared with the data collected from 1980-1992. The highest mortality rates occur during the months of April through August, with Greens between 27.0 and 38.9 cm curved carapace length (CCL) and Kemps Ridleys between 22.0 and 51.9 cm CCL being hit the hardest. Strandings of both species of turtles were most frequent on highly populated beaches in Charleston County during the peak recreation and shrimp-trawling season. The results of this study suggest that, although humans have a negative impact on sea turtle populations overall, the current conservation efforts are paying off and we are slowly seeing an increase in numbers. Worldwide research, education, and legislative action should continue to be taken in order to further protect all species of turtles.


March 27, 2006
Celia Barbieri
Diatomaceous Earth as a De-worming Treatment for Pigs on the Warren WilsonCollege Farm
Mentor: Dr. Jeff Holmes

Abstract: Diatomaceous Earth (DE) is a geological deposit consisting of the crushed skeletons of diatoms, which are unicellular organisms that form intricate skeletons of amorphous silica.  Diatomaceous earth has been thought to have de-worming capabilities because it is a collection of microscopic shards of glass that mechanically pierce the protective coating of parasites.  The Warren Wilson College Farm currently uses, Ivermectin (Ivomec), a conventional, chemical,
de-worming treatment.  The objective of this study was t
o determine the efficacy of Diatomaceous Earth as an alternative to Ivomec for de-worming pigs. 

Five litters of piglets were born in September 05- October 05, at weaning or roughly 28 days of age, I divided each litter by sex and weight, into an Ivomec treatment group and a non-Ivomec group.  The entire Field was fed 2lb. DE/ ton feed from October till February and the 40lb. DE/ ton feed from February till March.  I took weights and fecal samples rectally from each pig on five sample dates.  I used the double centrifugation method to produce slides and count parasite eggs.  I identified and counted roundworm (Ascaris suum), whipworm (Trichuris suis), Strongyloides (Oesophagstomum dentatum), and Coccidia (Isopora suis) eggs.  A set of contingency tables and Fisher Exact tests were used in order to compare the parasite prevalence between treatment groups and sample dates.  A range of p-values were found from 0.359-1.0, indicating no statistically significant differences for any of the comparisons made.   I also used the weight measurements to compare the growth rates of the pigs treated with Ivomec and those that were not.  The average weights at weaning and at the final sample date were compared using a t-test, and no significant difference was found between the means.  These results conclude that there was no evidence that Ivomec made a difference in weight gain or intestinal parasite prevalence.  Comparing the data collected before and after the increase in DE dose, does not support any dramatic effect on parasite levels or weight gains. In order to suggest the use of Diatomaceous earth as a de-worming treatment on the WWC farm, further research must be done.


April 3, 2006
Jesenia Mejias
Antioxidant Properties of Guava Psidium guajava L.
Mentor: Dr. Victoria Collins

Abstract: Antioxidants, a dietary requirement for humans, prevent and regulate free radicals formed during regular metabolic processes.  Free radicals are reactive, unstable molecules with an unpaired electron, which can cause damage to cell membranes, proteins, and nucleic acids. Antioxidant capacity of a food can be estimated by its ability to reduce the stable free radical 1,1-diphenyl,2-picrylhydrazyl (DPPH*). Guava, a part of the traditional Hispanic diet, is a berry which can be eaten raw or processed and is found throughout the world in the Tropics.  The objectives of the study are to determine the antioxidant capacity of guava fruits and juices using DPPH*, to compare four brands of bottled guava juices to each other and to fresh fruits, and to compare the effects of ripeness on the antioxidant capacity of guava fruits.  Three bottles of four brands of guava juice and twenty-nine guavas were purchased at a South Florida market.  Methanol extracts of guava fruits and juices were mixed with methanolic DPPH* solution and the reduction of the DPPH* radical was measured by decrease in absorbance at 520 nm. Absorbance decrease due to known amounts of vitamin C were used as reference for the free radical scavenging capacity of guava.  Antioxidant capacities of the juice brands varied significantly from 9.0 to 45. mg vitamin C equivalent per 100 mL of juice. The guavas were significantly different from one ripeness category to another.  The mean of the young and ripe guavas (38.07 mg vitamin C per ~100 g fruit) contained a significantly greater amount of vitamin C equivalent than the mean of all the juices (24.31 mg vitamin C per 100 mL juice) which are comparable serving sizes.  The variability of the juice data could be due to the shelf life of juices and the varying fruit content among the brands.  These data may help consumers make more informed choices on the types of fruits to buy for maximum vitamin C intake.  An increase in dietary antioxidants may decrease cellular dysfunction caused by free radicals damage, therefore decreasing the risk of many health problems.



April 3, 2006
Richard Peart
Computational Modelling of Photochemical Smog

Mentor: Dr. Dean C. Kahl

Abstract: Smog is a system of air pollutants that interact with each other in the presence of sunlight, creating ground level ozone. Ground level ozone is harmful to plants and humans. Long term exposure to ozone has been shown to reduce pulmonary function and hinder plant reproduction and storage mechanisms. It is therefore important that the chemistry of smog formation be studied. Additionally, air pollution legislation is based on chemical and mathematical models that describe smog formation. Smog chambers are used to analyze smog under controlled weather free environments. Smog chambers are
8 m by 8 m by 8m Teflon lined rooms that may be used to simulate atmospheric conditions and simulate the formation of smog. Mathematical modelling is used to simulate the formation of photochemical smog. In this study radioactive decay and smog formation were modelled using Java and two numerical integration methods, the Euler method and the Runge-Kutta 4 method. The results of these numerical models were compared to the analytical solution (radioactive decay model) and actual smog chamber data (smog model). The results suggest that Runge-Kutta 4 is ideal for modelling radioactive decay, as the relative error between the analytical and Runge-Kutta 4 model was 0%. The results also suggest that there is no difference between the Runge Kutta 4 (RK4) and the Euler's method when used to model smog formation. 


April 10, 2006
Brandon  Schmandt
Evaluating Stormwater Management at the Wal-Mart Supercenter in Asheville
Mentor: Dr. Mark Brenner

North Carolina implemented the National Pollution Discharge Elimination System (NPDES) Phase II in 2004.  The policy mandates regulation of stormwater discharge in the city of Asheville.  NPDES Phase II is intended to prevent sedimentation of rivers and erosion by requiring developments to use Best Management Practices (BMP) designed to remove 85 percent of sediments before stormwater discharge.  The Wal-Mart Supercenter development adjacent to the Swannanoa River was one of the first developments in Asheville to be subject to the NPDES Phase II regulations.  BMP employed at the development include filter strips and retention basins.  Stormwater discharge has been shown to increase total suspended solids (TSS) and Pb concentration in rivers (Deletic 2005; Gardner and Carey 2004).  My first objective was to evaluate how effectively the stormwater management system at the Wal-Mart Supercenter prevents sediments and Pb from being discharged into the Swannanoa River.  My second objective was to determine if Pb concentration relative to TSS was higher in the Swannanoa River or in a retention basin at the site of the Wal-Mart Supercenter.  My methods for analysis of TSS and total Pb concnetration came from Standard Methods for the Examination of Water and Wastewater (APHA 1999).  There was no significant difference between upstream and downstream samples for TSS and total Pb concentration.  Four out of five samples showed significantly higher TSS solids in the Swannanoa River than in a retention basin, and significantly higher Pb concentration in a retention basin than in the Swannanoa River.  The data indicate that stormwater from the Wal-Mart Supercenter does not significantly impact TSS and Pb concentration in the Swannanoa River.  The data suggest that suspended solids in a retention basin have a higher lead concentration than suspended solids in the Swannanoa River.  Future research concerning chemical pollutants in retention basins could indicate a need for regulation of stormwater pollutants other than sediments.


April 10, 2006
Stacey Hollis
Heavy Metals In Tern Prey
Mentor: Dr. John Brock

Abstract: Rising concentrations of heavy metal pollution can have detrimental impacts on marine ecosystems. Through biomagnification of across food chains and bioaccumulation within individual species, heavy metals may influence developmental abnormalities in seabirds. Common (Sterna hirundo) Terns are piscivorous seabirds that communally nest on inshore and offshore islands off the coast of the eastern United States. They are generalists, which lead to occurrences of fluctuations in diet across seasons based on prey availability. Since 2001, offspring of these terns have been observed with unexplained abnormalities in some inshore island-breeding colonies. Researchers are investigating the cause of these defects by analyzing chicks and eggs for heavy metals. Through Warren Wilson College, I analyzed the discarded prey species of these birds for four heavy metals, Pb, Zn, Cd, and Cr. My objective was to determine whether there is difference between metal concentrations in tern prey and their proximity to shore. Secondly, to determine whether there is a difference in metal concentrations of different species that make up a tern diet.

I collected prey items from an inshore and an offshore island tern colony off the coast of Maine, Seal Island National Wildlife Refuge and Pond Island NWR. I analyzed my samples using an inductively coupled plasma-optical emission spectrometer. In my sample groups, I found detectable levels of chromium, lead and zinc. No detectable levels of cadmium were observed in any of my samples.  In my island comparisons, I found no significant difference in average heavy metal concentrations between Seal and Pond Island. In my species comparison, I found stickleback to have significantly higher concentrations of chromium and zinc than butterfish. My statistical results suggest that the metals I tested for might not contribute to the inshore phenomenon of chick abnormalities. Additionally, the difference in zinc concentrations found between stickleback and butterfish suggest that the fluctuations in the generalist diet of the common tern might have an influence on tern metal levels across years based on prey availability. In comparing metal levels in my samples to literature values, I found that, out of the concentrations I observed in my samples, lead met what are considered be elevated levels. In addition to ruling out the metals I tested for as cause for the tern chick abnormalities, I believe that my research was a good introductory study on metal levels in fish species and that additional research could be made in regard to these and other metals found in Maine’s coastal waters.


April 17, 2006
Tim Manney
The Effects of Cooking Time on the Strength of Pitch Glue made from Norway spruce (Picea abies) Oleoresin
Mentor:  Dr. Mark Brenner

Abstract: This study explores the relationship between the strength of pitch glue made from Norway spruce (Picea abies) oleoresin and cooking time.  Pitch glue was gathered from seven trees, each of which served as experimental replicates, during the fall of 2005.  Each replicate was heated separately, equal amounts skimmed from the top, and mixed with half that volume of charcoal dust to produce loaded resin glue.  Two samples of glue were taken from the mixture every fifteen minutes for two hours.  The first was used to create a glue bond that was subsequently subjected to strength tests to estimate the strength of the glue at that cooking time.  The second was used to measure the density of the glue at that time.  A repeated measures ANOVA indicated that glue from the 15 minute time group was significantly stronger than glue from the 105 minute time group (p<0.05) and 120 minute time group (p<0.01).  A linear regression analysis indicated a significant negative relationship between strength and cooking time (p=0.048) with r2=0.1382.  The density of the 15 minute time group was significantly less than the 105 minute (p<0.0001) and 120 minute time groups (p<0.0001).  These results suggest that pitch glue made from Norway spruce oleoresin can be overcooked and as a result weakened.    The significantly lower density of pitch glue from the 15 minute time group suggests higher proportions of volatile compounds.  The volatiles plasticize the resin and could be a contributing factor to the significant difference in strength means.

17 April 2006
Lily Doyle
Gender Selection Through Olfactory Cues
Mentor: Dr. Greg Ettl

Abstract: Many mammals communicate through pheromones, which influence the behavior or physiology of other organisms (Martins et al. 2005). Although most animals can communicate through pheromones, primates are thought to have limited or no capability of sensing them (Keverne et al. 2004). Whether or not humans can communicate through pheromones, heterosexual males and females may favor the scent of the opposite sex (Martins et al. 2005). The objective of this study is to test the attractiveness of heterosexual male and female underarm scents, commercial pheromones and boar scent on males and females. Underarm scents were collected from six students, a male and female from each objective scent categories; mild, moderate and strong scents. Male and female commercial pheromone attractants were tested as well as boar saliva. Each trial compared two scents and a control that were tested by 30 heterosexual males and 30 heterosexual females. Testers smelled and rated each sample on a visual analog scale and ANOVA was used to compare responses. Overall there was a negative or neutral response to human scents. Male and female testers rated moderate male scent, strong male and female scents, and commercial pheromones significantly lower than controls. Male commercial pheromones were rated significantly lower than mild male scent and the control, with p-values less than 0.01.  There was no significant difference between male and boar scent rating by male and female testers.

April 24, 2006
Casey C. Gish
Isolating Wild Strains of Brewers Yeast (Saccharomyces cerevisiae) for Eventual Comparison of Flavor Compounds, and Tastes, of Fermentation Product
Mentor: Dr. Michael Torres

AbstractSaccharomyces cerevisiae, a species of budding yeast, belonging to the  fungi kingdom, is a single celled eukaryotic organism whose size can range from 5-10 micrometers in diameter.  It is thought that yeast is the oldest organism cultivated by humans used for its ability to leaven bread and produce alcohol, known as fermentation.  Early brewers of beer relied on wild yeasts and bacteria for fermentation.  Beers fermented by wild microorganisms are known as spontaneously fermented.  Using wild microorganisms as opposed to lab-cultured yeast produced unique regional flavored beers.  The objective of this study was to culture two wild strains of Saccharomyces cerevisiae, from two different regions, for eventual comparison of dominant flavor compounds produced during fermentation. 
Two wild strains of S. cerevisiae were cultured.  One from Western North Carolina located in a mountainous temperate region, at an elevation of approximately 2,000 feet with average precipitation of 54 inches.  The second strain was isolated from Southern Maryland located at sea level on the Chesapeake Bay with average precipitation of 41 inches.  Starting with a simple glucose media left open to the air of these regions, various other tests were applied to the isolated microorganisms, resulting in one unknown from each testing positive as Saccharomyces cerevisiae.  While the two strains isolated were unable to ferment low gravity wort, this study verified reliable and inexpensive methods for culturing wild strains of S. cerevisiae.  Future work with these yeast strains will potentially result in viable brewing yeast capable of producing a uniquely flavored beer.

April 24th, 2006
Kim Hall
The Flirtatious Behaviors Between Single Heterosexuals
Mentor: Dr. Vicki Garlock

Abstract: Flirtation has been around since the beginning of time; however, there haven’t been many studies that deal with the actual behavior of flirtation in the field of psychology.  Studies have been conducted using video interviews, voice recording, and open-ended questionnaires about relationship satisfaction.  The objectives of this study were to develop a questionnaire to assess flirtatious behavior in men and women.  I also wanted to determine whether or not there was any difference between the flirtatious behaviors of men and women and to look at what flirtatious behaviors might occur in combination with each other.  A survey was created and distributed.  The data were then analyzed with T-tests, one-way ANOVAs and a Principle Components Analysis (PCA).  PCA is a type of factor analysis that groups similar items into different factors.  Statistically significant gender differences were found on the Self-Flirt survey and on the Friend Flirt survey.  No statistical significance was found between men and women when looking at the Flirting Thoughts survey.  One of the ANOVAs indicated that when Friend Flirt scores were analyzed according to self-assessed measures of attractiveness, the results were significant.  When scores on the other two surveys were analyzed based on responses to the attractiveness questions, no other statistically significant differences were found.  The PCA confirmed that certain flirtatious behaviors do lie together.

May 1, 2006
Colleen Blaine
The morphology of Spotted Salamanders (Ambystoma maculatum) in the presence of two different caged predators.
Mentor: Dr. Lou Weber

Abstract:  Predator and prey interactions can influence the life history of a species.  Aquatic species may be able to sense the chemical presence of a predator in the water through kairomones, a chemical signal between species.  This can be tested in the laboratory by using a mesocosm with a caged predator.  The objective of this study was to conduct a laboratory experiment in 2005 to determine whether Spotted Salamander larvae growth is affected by the presence of caged Red-Spotted Newts and caged Green Darner Dragonfly larvae.  A natural pond survey at Warren Wilson College in Asheville, NC was also conducted in 2005 and 2006 to determine if the predators co-exist with Spotted Salamanders.  Sixty salamanders spent thirty days in mesocosms with one of three treatments; Caged Green Darner Dragonfly larvae, Caged Red-Spotted Newt, or an empty cage (no predator).  The resulting larval lengths were analyzed using an ANOVA.  Spotted Salamander larvae raised in the presence of Red-Spotted Newts were significantly smaller (p= 0.025) in mean total length than salamander larvae raised in the presence of the Green Darner Dragonfly larvae.  The Spotted Salamander larvae raised with Red-Spotted Newts were significantly smaller (p= 0.0061) in mean tail width from the salamander larvae raised in the presence of both the Green Darner Dragonfly larvae and with no predator.  The Spotted Salamander larvae raised with the Red-Spotted Newt mean head width was smaller (p= 0.058) than the other two treatments, but not significant.  The Spotted Salamander larvae raised with the Red-Spotted Newt mean tail length had no significant difference (p= 0.12)between the treatments.  The growth of spotted salamanders appears to be influenced by the presence of the Red-Spotted Newt.


May 1, 2006
Lucas Blass
Archaic and Modern Approaches to Case Hardening Mild Steel
Mentor: Dr. Victoria Collins

Abstract: The process of case hardening imparts a hard outer layer to steel, while maintaining flexibility in the softer inner core of the metal. 

This study investigated differences in hardness produced by between different methods of case hardening steel (the Rockwell hardness scale is a standard measure of steel hardness, and was used in this study).  Pieces of low carbon steel were subjected to five different treatments: charcoal, bone meal, industrial compound (Ecco carb), quenched and untreated, and unquenched and untreated control. All samples except for the control were encased in sections of pipe and heated at 1650° F (900° C) for 8 hours, then quenched in oil.  Samples were tested for control on the Rockwell scale.  Mean hardness for the three replications of each treatment were compared using an ANOVA.  Mean hardness is shown below, with standard error in the bottom row.

HRC Values for Five Treatments

 

Charcoal

Bone Meal

Ecco Carb

Oil Quench

Control

Hardness

41.75

39.83

61.5

29.167

27.333

Standard Error

3.031

3.06

1.258

0.441

0.8819

The industrial compound was found to yield the most significant increase in hardness, although the bone meal and charcoal treatment groups also produced significant hardness gains, compared to the control.  The type of hardness gain produced by the Ecco Carb treatment is suitable for nearly any case hardening treatment, including but not limited to gun actions, crankshafts, and gears.  The hardness gains produced by the charcoal and bone meal treatments were near the values needed for applications such as pry bars and other non-cutting tools.  Although hardness gain was more substantial in the industrial Ecco Carb treatment, it contains barium carbonate, a chemical which is classified as hazardous waste.  This may mean that Ecco Carb would be an inappropriate compound for a home shop application.


May 8, 2006
Hannah L. Barks
The effectiveness of the DSI Pro camera for the determination of the relative ages of different star clusters
 Mentor: Dr. Donald F. Collins

Abstract: A star cluster is a group of stars that are approximately the same age, but are not all the same size or mass. In a young star cluster, the stars lie on the main sequence of the luminosity versus color index diagram with the massive, hot, blue stars being brightest and the less massive, cooler, red stars being the faintest. In an old star cluster, the hot massive stars have evolved off the main sequence and have migrated into the high luminosity, red region of the color index diagram. The objective of this experiment was to determine if the inexpensive Meade Deep Sky Imager Pro (DSI-Pro) camera coupled with a 20-cm Schmidt Cassegrain telescope could be used for the determination of the relative ages of different star clusters. Four separate Meade filters: infrared (IR) block and the band-passes for red, green and blue were used in this experiment. The band-pass of each filter was obtained using a spectrophotometer. The transmission spectra showed that each filter transmitted IR light along with its designated color, which diluted the color index. Aperture photometry was used to measure the intensity of each star for each color band. The green luminosity and color index were then calculated and plotted on a color index diagram (similar to a Hertzsprung-Russell diagram). With corrections for the dilution of the color index by IR light, different star clusters were successfully observed at different stages of evolution.