Jennifer Ousley
Population Genetics of Captive Caracal caracal damarensis
January 29, 2001.  Mentor: Dr. Jeff Holmes

Abstract: In this study, I set out to determine if the captive caracal  population, at the Carnivore Preservation Trust, was suffering from genetic  problems such as inbreeding depression. The main objective was to determine  the number of heterozygous individuals using polymerase chain reaction (PCR),  electrophoresis, and the Hardy-Weinberg equilibrium. Three different  microsatellites were selected for analysis. After blood samples were  collected, the DNA was isolated and several PCR reactions were run using  multiple variables and 3 different primer pairs. The dilutions and  concentrations of the DNA, Mg2+, primers and Taq enzyme were varied. Thus far,  no PCR reactions have been successful. Despite the lack of success, I am still  convinced that this research is worthwhile and will continue trying other  methods of DNA purification in order to obtain a successful PCR. With this  information, I will be able to determine if this population is suffering from  loss of genetic variation or inbreeding depression. I will also be able to  make suggestions as to which individuals should be bred in order to maintain  the highest possible genetic diversity, and whether it is essential to  introduce new individuals.



S. Sky Stephens
Analysis of the Defensive Secretions of Xystomodidae Millipede
February 5, 2001.  Mentor: Dr. Dean C. Kahl

Abstract: Several species of millipedes secrete chemical substances. Member of the  family Xystodemidae characteristically produce a mixture of cyanohydrins  in their defensive secretions. An analysis of the defensive secretions  using a gas chromatograph/mass spectrophotometer was used to determine the  composition of the cyanohydrins and other components of the defensive  secretions. Components identified include mandelonitrile, benzoyl  cyanide, benzaldehyde, hydrogen cyanide, and acetophenone. Repeated  samplings of individuals indicated that the production of these defensive  secretions requires about two weeks. Preliminary results suggest that the  defensive secretions are available to the organism in limited quantities  and the capacity for producing and releasing these compounds varies  through the life cycle of the species. In continuing this study I intend  to quantify the relative amounts of each component of the defensive  secretions, and compare the defensive secretions of adult and adolescent  millipedes.



Megan Wedding
The effect of intercropping on the yield of corn (Zea mays L.) and peanuts (Arachis hypogaea L.).
February 12, 2001.  Mentor: Dr. Mark A. Boudreau

Abstract: This experiment began due to a personal interest in finding alternatives to the conventional agriculture production methods of the United States. Diversity in cropping strategy has been lost to the continual monocropping of grains nationwide. The objective of this study was to determine if intercropping, growing two or more crops in the same field simultaneously, not only increases agricultural diversity, but also yield. Corn and peanuts were chosen to intercrop due to their compatibility in climate needs, nutrient uptake, and mechanical harvesting. The heights of corn and peanut plants, as well as the biomass of the peanuts were sampled prior to harvest from each of the eighteen plots (six treatments were randomized amongst three blocks). Corn and peanut yields were to be determined and applied to the land equivalent ratio (LER). This ratio provides a quantity for the amount of land needed to grow in monoculture what is grown in polyculture. However, two days after harvest while drying in the field, crows ate the peanuts. Data was analyzed using a one-way analysis of variance as well as the Tukeys and Kruskal-Wallis tests. Although an LER was unable to be calculated, significant differences were found between the height of the intercropped corn and the monocropped corn, as well as between the biomass of intercropped and monocropped peanuts. With the information provided by this experiment and similar research, intercropping should be seen as a viable option for farmers.



Adam M. Wallace , Does Supplemental Food Affect the Diet Preferences of Rainbow Trout (Onchorhynchus mykiss) in Looking Glass Creek?
February 19, 2001.  Mentor: Dr. Mark Brenner

Abstract: Invertebrates that were found in the stomachs of rainbow trout (Onchorhynchus mykiss) that receive supplemental feeding were compared to the stomach contents of rainbow trout that were not receiving supplemental food. The optimal foraging theory states that when resources are abundant, foragers should concentrate on their most favored prey, resulting in a narrow diet breadth. As resource abundance declines, foragers should expand their diet breadth to include less-favored items. It is hypothesized that trout receiving supplemental food would have some sort of diet preference.
A non-parametric two way ANOVA was the statistical analysis used to analyze the data. It tested for an interaction between stream site (fed or unfed) and numbers of insects of each order found in the stomachs of the trout.  In running this analysis a p-value of less than 0.0001 was obtained, suggesting that there is a significant difference in the types of insects found in the stomachs of the trout from each section. This supports the hypothesis and the optimal foraging theory.


Jeremy Schewe
A Comparison of Root Yield of Cultivated Versus Wild-crafted Golden Seal, Hydrastis canadensis.
February 19, 2001.  Mentor: Dr. Mark Boudreau

Abstract: Hydrastis canadensis (goldenseal) is an endangered perennial, native to eastern mixed-mesophytic forests. Demands from the growing medicinal-herbs market have amplified existing pressure on wild populations. Cultivation of goldenseal has gained some popularity over recent decades. The first objective was to determine whether significant differences root yield would be detected between cultivated and native stands of H. canadensis for similar climatic areas. The second objective was to compare the results of the eastern Ohio studies with the results of the western North Carolina studies to determine if any major differences could be found for the same variables mentioned above. My hypothesis was that cultivated goldenseal would demonstrate higher dry weight yields than the wild populations and no significant difference would be found between the Ohio and North Carolina results. A randomized block analysis was used to compare the wild and cultivated treatments. Results indicate that cultivated populations have higher yields and that no significant difference exists between Ohio and North Carolina for both treatments.


Jammie Kohen
The effects of hypoxia on the epifaunal community of the Rhode River
March 5, 2001.  Mentor:  Dr. Paul Bartels

Abstract: The Chesapeake Bay is subject to occurrences of hypoxia, or low dissolved oxygen levels, especially in the summer.  During the summer of 2000, the effects of hypoxia on epifaunal organisms, or those that inhabit or move over the substrate in aquatic habitats, were studied in the Rhode River, a tributary of the Chesapeake Bay located in Edgewater, Maryland near Annapolis.  The goal of this project was primarily to find the easiest and most successful method for studying the effects of hypoxia in a laboratory setting, so that a larger project on hypoxia can be completed.  The first hypothesis of this experiment was that with the lowering of dissolved oxygen, the epifaunal organisms growing on settling plates will be altered, more specifically, that the sessile organisms will die while the more mobile organisms will try to escape to a place where there is more dissolved oxygen.  The other hypothesis was that the bryozoan, Victorella sp., survives hypoxic episodes allowing it to spread.  Epifaunal organisms were collected off of the Smithsonian Environmental Research Centerís dock using settling plates.  Six main species were collected, including the bryozoan, Victorella sp. and the mud worm, Polydora ligni.  The treatments included 36 hours of hypoxia (DO=0.5 to 1.5 mg/L), 30 hours of hypoxia, 24 hours of hypoxia, 12 hours of hypoxia, 36 hours of normoxia (DO=5.0 mg/L and higher), and a control that remained in the water for the entire experiment.  The differences in percent coverage for both Polydora ligni and Victorella sp. were analyzed using an arc sin transformation and a one-way ANOVA.  There was no significant difference between the treatments for either organism.  To test the second hypothesis, the first two replicates were re-deployed off of the dock following treatment.  The difference in percent coverage of Victorella sp. before treatment and following redeployment was analyzed using an arc sin transformation of the data and a one-way ANOVA.  There was no significant difference found between the treatments.  Hypoxia lasting 30 to 36 hours caused blackening of the plates, evacuation of Polydora ligni from their tubes, and death of Polydora ligni.



Autumn Sorensen
Fatty Acid Analysis in Grass and Grain-Finished Beef
March 12, 2001.  Mentors: Dr. Robert Eckstein, Dr. Victoria P. Collins

Abstract: The overall objective of this study was to compare grass-finished and grain-finished Warren Wilson College beef in three aspects: fatty acid composition and consumer health, consumer acceptability, and economic feasibility.  This portion of the project dealt with the fatty acid analysis.  A relationship between dietary fats and many different diseases has been well established.  More recent research has suggested a link between some of these diseases (especially cardiovascular disease) and an imbalance in the omega-6:omega-3 fatty acid ratio (Bruckner, 2000).

The objectives of  this research was to compare the amounts of omega-6 and omega-3 fatty acids in grass and grain-finished beef.  The omega-6 fatty acids measured were linoleic acid and arachidonic acid.  The omega-3 fatty acids measured were linolenic acid and docosahexaenoic acid. The hypothesis was that there would be different amounts of omega-6 fatty acids in the grass and grain-finished groups, that there would be different amounts of omega-3 fatty acids in both groups, and that the omega-6:omega-3 fatty acid ratio would be different in the grass and grain-finished groups.

Twenty Warren Wilson steers were separated into two groups for finishing in the summer of 2000.  One group was fed a grain-based diet while the other group was fed a grass-based diet.  After the 89 day finishing period, both groups were slaughtered.  Two animals were removed from the study during the finishing period for reasons unrelated to the study.  Samples were taken from between the 12th and 13th ribs of the longissimus dorsi muscle (one sample form each of the 18 steers).  An 800-1000 mg sample of subcutaneous fat was removed and vacuum dried.  The sample was then chopped up and the fatty acids were converted to fatty acid methyl esters (FAME) with methanol and HCl in toluene. The FAME were separated and quantified using a gas chromatograph/flame ionization detector.  The percentages of the four FAME were compared using an unpaired two-tailed t-test.

The mean concentration of linoleic acid in the grain-finished group was 2.3%, and 3.7% in the grass-finished group (p=0.0007).  The mean concentration of linolenic acid in the grain-finished group was 0.4%, and 1.2% in the grass-finished group (p<0.0001).  The mean concentration of aracidonic acid was 0.75% in the grain-finished group and 0.47% in the grass-finished group (p=0.0285).  The mean concentration of docosahexaenoic acid in the grain-finished group was 0.15%, and 0.32% in the grass-finished group (p=<0.0001).  The total omega-6:omega-3 fatty acid ratio in the grain-finished group was 3.0:1.0, and 2.7:1.0 in the grass-finished group (p=0.5690).


Erin McNally
Sensory Evaluation and Economic Feasibility of Grass-finished vs. Grain-finished Warren Wilson Beef
March 12, 2001. Mentor:  Dr. Victoria Collins

Abstract:  The overall objective of this project was to compare grain-finished and grass-finished Warren Wilson College beef in three aspects:  fatty acid composition, consumer acceptability and economic feasibility. This portion of the project evaluated consumer acceptability and economic feasibility. The objectives of the sensory evaluation portion of the study were first to determine if panelists were able to discern a difference between the meat of the two finishing types and secondly to determine if the meat from the two finishing methods would receive different scores by panelists in the categories of tenderness, beef flavor and overall acceptability.  The objective of the economic feasibility portion of the study was to determine if there was a difference in the productivity of the two methods.

     Consumer acceptability and economic feasibility are important for farmers to consider when making a change from grain-finishing to grass-finishing.  Numerous studies have been conducted comparing the palatability characteristics of grass and grain-finished beef with variable results.  Some studies found no significant difference in palatability (Mills et al., 1992, Reagan et al.,1977).  Some studies found that panelists preferred grain-finished (Bowling et al., 1977, Mitchell et al., 1991, Larick et al., 1987).  Still other studies found that panelists preferred grass-finished (Huffman and Griffey, 1975,  Schupp et al., 1976).

     In the summer of 2000 twenty Warren Wilson steers were separated into two groups for finishing.  One group was fed a grain-based diet, while the other group was fed a grass-based diet.  After the 89 day finishing period, both groups were slaughtered.  To determine productivity the animals were weighed at the start of the finishing period and at the end of the finishing period.  The average daily gain (ADG) during the finishing period was calculated.  Additionally, the hanging weight of the carcasses and the cut and wrapped weights of the carcasses were obtained.  The data was analyzed using unpaired t-tests, testing the assumption of normality each time. The live weights for the grain and the grass-finished animals, respectively, were 1171 lb and 1161 lb (p=0.7437). The hanging weights for the grass and grain, respectively, were 652 lb and 632 lb  (p= 0.3475).  The cut and wrapped weights of the grain and grass-fed animals, respectively, were 467 lb and 492 lb (p=0.0433).  The ADGs of the grass and grain, respectively, were 2.26 lb/day and 2.50 lb/day (p=0.3054).

     The carcasses were hung for two weeks at seven degrees Celsius.  Fourteen grass-finished and fourteen grain-finished rib-eye steaks were obtained from a total of ten carcasses.  An untrained sensory panel of twenty-six students and staff from Warren Wilson College evaluated the cooked beef.  In the same/different test the panelists received two plates:  one plate with pieces of the same dietary treatment and one plate with pieces of different dietary treatments.  The panelists indicated whether or not the pieces of steak were the same or different.  For the same plates, the proportion of correct responses was 0.31.  For the different plates, the proportion of correct responses was 0.69.  In the attribute test panelists ranked two pieces of grass-finished steak and two pieces of grain-finished steak in the categories of tenderness, beef flavor and overall acceptability, by placing a mark on a 10 cm line.  The marked distances were analyzed using a Wilcoxon-matched pairs signed ranks test.  The mean scores for grain and grass-finished, respectively, in the tenderness category were 7.80 and 7.75 (p> 0.9999).  The mean scores for beef flavor in the grain and grass-finished, respectively, were 8.19 and 7.00 (p =0.0047).  The mean scores for overall acceptability for the grain and the grass-finished, respectively, were 8.42and 7.38 (p=0.0289).



April Morgan, Corrosion Testing of a Ceramic Waste Form using Noncomplexing Buffers
April 2, 2001.  Mentors: Lester R. Morss, Argonne National Laboratory; Dr. Dean C. Kahl, Warren Wilson College

Abstract: Radioactive waste salts and uranium metal are produced by electrometallurgical treatment of sodium-bonded spent nuclear fuel from an experimental breeder reactor. A Ceramic Waste Form developed at Argonne National Laboratory will be used for long term immobilization of radioactive waste salts in a repository setting.  The objectives of this research appointment were (1) to determine the dissolution rates of the developmental Ceramic Waste Form (glass-bonded sodalite) and its sodalite and glass components at controlled pH values in noncomplexing buffer solutions, and (2) to compare these data with data obtained from previous dissolution tests with potassium hydrogen phthalate, tris(hydroxymethyl)aminomethane, and boric acid buffers.  Noncomplexing buffer solutions at pH6, pH8, and pH10 were prepared from aqueous solutions of buffers, LiOH, and HNO3.  Dissolution tests were carried out on the monolithic glass, sodalite, and ceramic waste form samples for durations of 2, 3, 5, 7, and 10 days at 70 *C.  Buffer leachates were acidified and analyzed for B, Na, Al, and Si concentrations via inductively coupled plasma atomic emission spectroscopy (ICP-AES).  The Si concentrations were used to calculate the normalized mass loss of each element.  The dissolution rates, or normalized release rates, of each element were determined by regression analysis.  The log (normalized release rate) was plotted as a function of pH.  These data were superimposed over previously generated v-plots to compare the new buffers with the buffers used in earlier dissolution tests conducted at Argonne National Laboratory.  The plots indicated that negligible complexation of silicon species by phthalate and tris(hydroxymethyl)aminomethane buffers occurred in previous corrosion tests.  The results suggest that the dissolution rates and pH dependence factors obtained from these and previous tests can be used to provide model parameters for CWF dissolution.



Dawn M. Hurley, The Fatty Acid Composition of Food Supplements
April 23, 2001.  Mentor: Dr. Victoria Collins

Abstract: Blue Green algae, actually cyanobacteria species of Spirulina maxima and Spirulina platensis, is a popular dietary supplement. Spirulina contains an uncommon fatty acid known as gamma linolenic acid (GLA). GLA has been shown in clinical studies to help reduce the effects of inflammatory diseases (J. Brooke Barham, et al, 2000), alleviate heart murmurs (J.S. Charnock, 1999), and protect stomach lining from ulcers(O.A. Shabanah, 1997). The objectives of this study were (1) to develop a method to separate and quantify GLA, (2) to measure the GLA content of Spirulina supplements, and (3) to compare spirulina supplements with evening primrose and borage oils as sources of GLA. Three brands of Spirulina: Natureís Way, Tree of Life, and Earthrise were used in this experiment. Four samples of each brand were converted to fatty acid methyl esters (FAMEís). The FAMEís were separated and quantified on a Shimadzu GC -14A polar column along with a F.A.M.E mix along with a mix of standard fatty acids including GLA. Samples consisted of three tablets and(0.41 * 0.6, 0.23*0.04, 0.41*0.08) mg of GLA respectively. The GLA content of commercial spirulina tablets were much lower than the amount used in clinical studies.