Examination of Environmental Factors Affecting Foraging Success of Common Terns (Sterna hirundo)

ABSTRACT.  Limited information is available on how environmental factors affect seabird foraging.  Because many seabird populations are threatened or endangered, better understanding of their feeding ecology may help conservation efforts.  The objective of this study was to determine if weather variables affect the foraging success of Common Terns (Sterna hirundo).  This study took place on Stratton Island in the southern Gulf of Maine.  Foraging success was indirectly estimated by counting the number of times an adult returned to its nest to feed its young.  Foraging success was tabulated during thirty-minute intervals for three-hour observation sessions.  A total of 24 Common Tern nests were observed for 128 hours from 20 June to 28 July, 1997.  Wind speed, visibility, precipitation, cloud cover, ambient temperature, and wind chill were recorded every thirty minutes during nest observations.  No significant correlations were found for foraging success and any of the weather variables when all the nests were examined together.  However, when the nests were divided into eight age categories, an analysis of variance indicated that foraging success increased significantly as the age of chicks increased (P<0.0001).  When age of chick was considered, there were still no significant trends between foraging success and any of the weather variables, except for age classes seven and eight (P=0.008, P=0.0522).  Foraging success of Common Terns decreased significantly on days when cloud cover was greater than 75%.  These data will be used as a baseline for longer-term research examining factors that affect the foraging of Common Terns.
 

The Nitration of Aniline in Concentrated Sulfuric Acid

Abstract.  An equimolar solution of aniline and nitric acid in approximately 90% sulfuric acid will form ortho-nitroaniline, meta-nitroaniline, and para-nitroaniline.  Past studies indicate that the isomer distribution is about 50% para, 50% meta and 1-5% ortho isomer (Holleman:1911), (Brickman:1965).  The exact product distibution depends on specific reactant conditions.  Previous examinations of this product distribution have used freezing point depression (Holleman: 1911) and UV absorbance techniques (Brickman: 1965).  These methods are outdated and analysis is complicated.  Our analysis uses High Performance Liquid Chromatography; a modern and accurate technique. 

In acidic solutions aniline is in equilibrium with the anilinium ion.  The anilinium ion is the dominant species under most nitration conditions.  However, reaction through aniline is expected to have a faster rate than reaction through the anilinium ion.  The nitration of aniline is curious because there is evidence that it occurs entirely via the anilinium ion (Brickman:1965, 1965a).  However, reaction throgh the anilinium ion cannot explain the high percentage of para isomer obtained.  Aniline is an ortho-para director, while the anilinium ion is a meta director.

It is important to ensure that the isomer distributions stated in the literature are correct.  My resuts support those of Holleman et. al. We found that the amount of para isomer is even higher than indicated in
the literature.

Brickman, Ridd (1965), Substituent Effects of Positive Poles in Aromatic  Substitution.  Part I.  J. Chem. Soc., 1965, 6845;  Substituant Effects of Positive Poles in Aromatic Substitution. Part II, J. Chem. Soc., , 6851

Holleman Hartgos, van der Linden (1911), Quantitative Untersuchungen uber die Nitrierung des Anilins.,  Ber.,  44 704

Computer Generated Conformational Energy Variation Calculations
 

Abstract: The purpose of this research was to design a method for using HyperChem molecular modeling software to predict the energy needed to change a halide substituted ethane from the anti form to the eclipsed form.  Compareing the HyperChem predictions to experimental results in order to test how well the software modeled chemical systems was a secondary goal.  The calculations would be performed by HyperChem usingmolecular mechanics as the calculation method.  Initially, a script, a small program for automating repetitive tasks, was used to perform the analysis. Later, an Excel macro, linked to HyperChem by a Dynamic Data Exchange connection was use to perform the analysis.  The results of the research show that the software simulated this chemical system very well, yielding an error of 4% from the literaturevalue for butane.  The script worked, but was very inefficient and was replaced by the Excel macro. The effect of increasing the size of the halide substituent was an increase in the barrier to rotation. The effect of increasing the number of halide substitutions increased the barrier to rotation as well. Completely substituting the ethane with halides demonstrated the software's ability to account for the polarizability of bromide and iodide.
 
 

Determining the Bioavailability of Zinc: Analysis of Vegetarian andOmnivorous Diets for Zinc and Phytate

Popular focus on high-fiber and vegetarian diets has piqued concern that Americans are receiving too little zinc from meals. Phytate, myo-inositol hexaphosphate, is considered to be one of the factors reducing the bioavailability of zinc in diets. Phytate complexes with zinc in the small intestine and forms insoluble ompounds which are not readily absorbed. Phytate is found in plant-based foods, especially soy, nuts, seeds, and whole grains. When meat products, which are generally high in zinc and have no phytate, are replaced with soy products, for example, which are low in zinc and high in phytate, the balance between phytate and zinc consumption is altered. This balance is recorded as the millimolar ratio between phytate and zinc. Ratios less than 12 are thought to have no effect on the bioavailability of zinc in humans, but a critical ratio has not yet been firmly established.

Samples of student-chosen meals from the college cafeteria were collected and frozen, homogenized, and analyzed for total mineral content, zinc, and phytate. Mineral content was calculated as percent ash after dry-ashing in a muffle furnace. Zinc content was determined by atomic absorption spectrophotometry. Phytate content was determined utilizing the methods of Fruhbeck, G. et al. - "A modified method for the indirect quantitative analysis of phytate in foodstuffs", Analytical Biochemistry, 225:206-212, 1995 - which included acid digestion, purification with anion-exchange columns, and colorimetric determination of phytate with the use of the Wade Reagent.  Millimolar ratios of phytate to zinc were calculated for each of the samples. Data from each analysis was pooled together into two groups, vegetarian and omnivorous, for statistical comparison using ANOVA tests. A significant difference was found between vegetarian and omnivorous diets in mean total mineral content (omnivorous diet higher, p=0.037) and in mean phytate content (vegetarian diet content higher, p=0.047). No significant differences were found between the mean zinc content or the mean millimolar ratios for the two diets.

Megan Tremper
Feb. 23, 1998
Advisor: Dr. Robert A. Eckstein

A Behavioral Study of Cattle Weaning Involving the Warren Wilson College Herd

This study investigated changes in movement, ingestion, and vocalization of beef cows and their calves before and after the weaning process and compared the behavioral changes of cows to those of calves. This study also attempted to compare the traditional method of weaning which allows no cow-calf contact to an alternative method that allows nose to nose contact but no nursing.  The alternative method failed due to the quality of  fences resulting in the abandonment of this objective.  Ten cow/calf pairs participated in the study to examine behavioral changes during the traditional method of weaning.  Observations took place three times a day, two consecutive days prior to weaning, the first day after weaning, the third day after weaning, and the fifth day after weaning.  Movement and ingestion were recorded every five seconds within a 30 second or 1 minute period of focal animal observation of each individual cow or calf.  The number of vocalizations were recorded during each observation period.  ANOVA and the Kruskal-Wallis non parametric tests, followed by multiple comparison tests showed that both cows and calves have a significant increase in the number of vocalizations after weaning and resume preweaning vocalization behavior by day three.  There was no significant change in the amount of movement for cows or calves. Ingestion significantly decreased for both cows and calves after weaning and they resumed preweaning ingestion levels by day five.  No significant difference was determined when comparing cows to calves for any of the observed behaviors.

Advisor: Dr. Mark Brenner

Comparison of Rainbow Trout (Onchorynchus mykiss) Diets in a Fed versus Unfed Section of a Southern Appalachian Stream
 

Insects from the stomachs of rainbow trout (Onchorynchus mykiss) that were receiving supplemental feeding of trout pellets were compared to a control group which was not receiving supplemental feeding.  Insects from both groups were also compared to a drift sample taken from the same stream.  The optimal foraging theory suggests that when food is more abundant organisms will be more  selective in their food choices.

The stomach contents of trout from the fed and unfed section were extracted using a stomach pump.  The drift sample was collected with a 363 micron drift net.  The insects found in the fed sections were compared to the insects from the unfed sections and each of these sections was compared to the insects collected in the drift sample.

A chi-square analysis was done of the stomach contents in the fed section with the drift sample, and of the unfed section with the drift sample.  There was a significant difference between the insects found in the stomachs of trout in the fed section versus the drift, but no significant difference between the stomach contents in the unfed section versus the drift.  This result indicates the trout in the fed section of the stream were more selective in the types of insects that they consumed. They seem to be able to rely on the pellets as their main source of food but they were discriminate about which insects they ate.  The trout in the unfed section consumed the food consistent with what was available in the drift since they did not receive supplemental feeding.  In order to find out what insects the trout were choosing a nonparametric Mann-Whitney test was done comparing the mean number of insects in each of the four orders per trout stomach in the fed section compared to the stomach sample in the unfed sections.  There was no significant difference between the fed versus unfed sections for the four insect orders tested.  In conclusion, the trout in the fed section were selective in the insects they choose to eat but this data did not show which insect order they preferred.
 

Alternative Farrowing Methods in the Warren Wilson College Swine Herd
 
Advisors: Dr. Paul Bartels and Dr. Robert Eckstein

Abstract. The practices of swine production are predominated by the use of farrowing crates, which are thought to reduce piglet mortality and human labor hours. Farrowing crates, which have been traditionally used on the Warren Wilson farm, are designed to restrict the sow’s movement to avoid the crushing of her piglets. However, recent studies indicate that restricting a sow’s movement can lead to psychological and physical problems in the sow (Rushen, J. P. Stereotyped Behaviour, "Adjunctive Drinking and the Feeding Periods of Tethered Sows", Animal Behaviour vol.32: 1059-1067. 1984; Janssens, Cecile J.J.G. et al. "Increased Cortisol Response to Exogeneous Adrenocorticotropic Hormone in Chronically Stressed Pigs: Influence of Housing Conditions", Journal of Animal Science vol. 72: 1771-1777, 1984). On the WWC farm, the use of farrowing crates has been observed to be particularly stressful on the sow due to the necessity of using a ramp to load her into the crate.

The purpose of this study was to determine if less-restrictive farrowing methods could maintain productivity levels in the Warren Wilson College herd and to produce a year-round farrowing procedure accordingly. To conduct this research, comparisons were made of the mortality rates and weaning weights of the piglets from three farrowing methods: crate farrowing, pen farrowing, and field farrowing. The data for these farrowing techniques represent all sows that farrowed during a 2-year period. Results of this experiment suggest no decrease in productivity in the less restrictive methods. Interestingly, a strong trend (p-value = .06) towards a decrease in piglet mortality in the pen farrowing method was found when the pen farrowing method was compared to the crate farrowing method.  Comparisons of individual sows revealed a decrease in mortality when sows were moved from a crate farrowing method to a pen farrowing method (p-value = .03). A decrease (p-value < .01) in mortality was also found when comparing an individual sow’s first and second time using the pen farrowing method, indicating possible learning on the part of the sow.

As a result of this research, the crates on the Warren Wilson farm are no longer in use and may be sold in the near future. The crate farrowing method has been replaced by the pen farrowing method, while additional work on the field farrowing method is needed before it can be incorporated into the farrowing procedures on the WWC farm. This study has also laid the groundwork for further research on the field farrowing method and developing additional less-restrictive farrowing methods.

Capacities of Indirect, Through-Pass Solar Dryers

Advisor: Dr. James Houser

Abstract. The present issues of population, food, and energy resources require the advancement of low technology, solar passive systems.  Past studies on passive, indirect, through-pass dryers led to a modified U-tube design.  Recent studies on the U-tube system were quantitative, but not comparative (Scanlin, 1997).  The acceptance of new technological designs requires comparison to determine changes in system dynamics.
            The three factors affecting dryer performance are temperature, air flow, and humidity. These factors were recorded in a U-tube and a Non-tube design at 11am, 12pm, and 1pm.  Five data sets were collected for each design.  My Null Hypothesis states that the U-tube system and the Non-tube system are not different in efficiency or performance. The mean temperatures (p=0.41), mean airflows (p=0.98), and mean humidities (p=0.44)  of the two systems did not differ significantly.  These variables were tested with a half pound of apples in the drying chamber for the two hour period.  The total amount of water lost from the apples dried in each design did not differ significantly  (p=0.18).  Multi-variable regression was performed on each system. Multi-variable regression revealed the Non-tube (r-sq=100%) to be a better predictor than the U-tube (r-sq14.4%).  My Null Hypothesis can not be rejected on the basis of my data.  The regression analysis shows the Non-tube to be an excellent predictor.  The U-tube is suggested to be a rather poor predictor.  This strongly suggest that there may be a difference between the systems.  The outcome of this study sets a foundation for further research on the optimization of variables, the affect of separate variables on dehydration, and passive solar design modeling.

The Low Temperature Growth of the Dogwood Anthracnose Pathogen, Discula destructiva, Red.

     Since 1983 dogwood anthracnose has been threatening the future of the eastern flowering dogwood, Cornus florida, L. in the southern appalchian mountains.  Many aspects of the disease have been studied to determine the influence of microclimate and abiotic factors on the severity of the dogwood infection.  This study was designed to determine if the pathogen continues to grow during the tree's dormant season, as no prior work has been done in this area.  Eighteen individual trees on the core campus of Warren Wilson College were chosen as subjects based on the following requirements:  understory location, diameter at breast height greater than 1.5 cm, epicormic sprouts, and drainage of greater than a ten degree slope.  Trees were classified as to the extent of their foliar symptoms in the fall of 1997 using the Mielke-Langdon dieback scale.  All of the trees were placed on a map of the campus, which was divided into four sectors containing eighty-five trees each.

      Growth of the fungus was recorded every two weeks from the point of attachment of an unabsciced leaf down the branch to where the fruiting bodies could no longer be seen using a 10X hand lens.  Daily growth was calculated and condition classes were compared to determine if the growth of the fungus was related to the initial involvement level of the tree. No difference was found using a parametric ANOVA and all of the trees were pooled and treated as a single population for the rest of the statistical tests.  The growth of the fungus did vary throughout the testing period. Using a non-parametric ANOVA a p-value of less than .0001 was obtained.  I attempted to explain this phenomena by obtaining temperature data from the national climatic data center and calculating a mean temperature for each period.  When I looked for a corrolation between temperature and growth rate using a Pearson linear regression, I obtained a r-value of -0.4088 and a p-value of 0.3147.  Temperature and the growth of the fungus are not related.  Looking for a corrolation, I compared the average day length to the mean growth rates.  The log of the growth rate data formed almost a perfectly straight line, with an r-value of -0.9482 and a p-value of 0.0003.  This suggests a very strong corrolation between day length and growth rate of the fungus.  As the day length increases the growth rate of the fungus decreases exponentially.

Diurnal Patterns of Cryptosporidium sp. Oocyst Shedding in the Warren Wilson College Cattle Herd

Advisor: Dr. Robert A. Eckstein

Abstract.  Cryptosporidium sp. is a waterborne, pathogenic protozoa. It is a zoonotic, gastrointestinal parasite and is transmitted by the oral-fecal route (Lindsay 1991). Crypto. is not removed from drinking water by current methods. In 1993, Crypto. caused an outbreak in Milwaukee that affected over 400,000 and killed 100 individuals (Payment 1997). At this point, there is no effective treatment for cryptosporidiosis, the gastrointestinal disease caused by Crypto. (Smith 1990).

Crypto. has extremely loose host specificity. The life cycle is complicated and includes both asexual and sexual reproductive stages within a host. The host may or may not show symptoms depending on the level of infection. The infectious result is environmentally hardy oocysts that are released in the feces.

This pathogen is of concern due to the close proximity of the Warren Wilson College Cattle Herd to the Swannanoa River. The farm is currently working to convert the water supplies for the cattle to municipal water. However, cattle still have access to the Swannanoa River in some areas.

My first goal was to determine the presence of Crypto. in the cattle herd using an ELISA test kit. Out of ten cows tested, six responded positive. I then used a Sheather’s sugar flotation technique to compare the quantities of oocysts being shed in the morning and the afternoon by these six cows. Due to diurnal fluctuations of corticosteroid blood levels in cattle, I hypothesized that the quantities of Crypto. oocysts would be greater in the morning than in the afternoon. However, no cows tested positive using the Sheather’s sugar flotation technique.
The ELISA test kits and the Sheather’s sugar flotation technique work by responding to different signals by the organism. At this point, I concluded that the six test cows were Crypto. carriers, but were not shedding oocysts in adequate quantities to be detected by the Sheather’s method. I then received a phone call from the Quality Control department of the supplying company of the ELISA kits. The company informed me that the kits were on factory recall due to false positives. I then re-tested the perceived positive cows using a new ELISA test, and found none of the cows to be positive. Therefore, further tests are needed to confirm the presence of Cryptosporidium sp. on the WWC farm.

Lindsay DS, and Blagburn BL. (1991) "Cryptosporidium parvum Infections of Swine." The Compendium. 13(5): 891-894.

Payment P, et al. (1997) "A Prospective Epidemiological Study of Gastrointestinal Health Effects Due to the Consumption of Drinking Water." International Journal of Environmental Health Research. 7(1): 5-31.

Smith HV, and Rose JB. (1990) "Waterborne Cryptosporidiosis." Parasitology Today. 6(1): 8-12.

Hair Straighteners and their Effect on Hair Fibers

Advisor: Dr. Dean C. Kahl

Hair chemical straighteners are widely known as relaxers. These relaxers are believed  to cause hair damage. The damage is due to the relaxers hydroxide actives at highly alkaline pH levels (pH=12 and higher).  High alkaline causes the intermediate matrix cells in the cortex to swell. This swelling pushes cuticle scales forward allowing the alkali in relaxer to react with the disulfide bonds in the hair fiber.  The disulfide bonds convert to single sulfur bonds called lanthionine.  Lanthionization stabilizes hair fibers in their new straight configuration. According to Wong, Wis-surel, and Epps, only 1/3 of all disulfide bonds in keratin fiber convert to lanthionine. The remaining bonds are responsible for maintaining the integrity of the fiber.

Supercontraction, which is the shorting of the hair fiber from its original length, appears to be an osmosis process.  Osmosis is the movement of water from a low ionic concentration to a high ionic concentration. Permanent hair straightening can only be achieved when hair fiber supercontract 5% or more of its own length and when the fiber is swollen. The swelling of the intercellular matrix causes the cortex to push the cuticle scales forward. Prolong exposure to an alkaline environment cause the cuticle scales to be out too far that they can not return to their initial position. The cuticle in this position become damaged and results to cuticle chipping. The protein chips from the cuticle can be collected to determine the aggressiveness of a chemical relaxer.

The purpose of this research is to apply "no lye" relaxer, prepared with a guanidine hydroxide activator, to kinky hair samples for protein determination. The Folin-Ciocalteu method is appropriate for protein determination because of its sensitivity. The Folin-Ciocalteu method is colorimetric method used to analyze surface damage  incurred by relaxer treatments. This method involves collecting protein chips, and mixing them with a diluted copper carbonate solution and later with a Folin-Ciocalteu reagent for spectrophotometric analysis. A beers law standard curve is prepared first using a known amounts of bovine serum albumin 10g/dL (BSA). The absorbencies of the unknown samples were quantified using the bovine serum albumin standard curve and were converted to mg protein per gram of hair. The standard error of the mean for the control group was .388953 g/g hair and the treated samples was .220332 mg/g hair. The calculated t-value was 1.097 for the mean protein loss from hair. The (one- tailed) t-test was used with a 90% confidence interval at two degrees of freedom. The variability due to the treated hair samples was found to be greater then the variability due to the different individuals in the control group. Protein chips were present in both the control group and the treated group. The protein chipping in the control group was expected because the cuticle is the outer barrier of the hair fiber and it suffers from mechanical damaging effects such as grooming, which is brushing, combing, and washing of the hair. The total average protein found in the control group was .090625mg protein/g hair and in the treated group 2.108 mg protein/g hair.

Megan C. Davies
May 11, 1998

Tropical Reforestation: Methods of Regeneration on a Bracken-Dominated Slope in Costa Rica

Advisor: Dr. William C. Davis

Reforestation of abandoned cattle pastures in Costa Rica is often hindered by the dominance of bracken fern in these areas.  Bracken fern, Pteridium aquilinum, is known to commonly invade burned and cut-over areas such as cattle pastures (Janzen 1983) and can slow or arrest the natural succession of these pastures into forests (Castro-Cortes 1997).  The goal of my study was 1)  to initiate reforestation on an abandoned cattle pasture that was dominated by bracken fern and 2) to find the most effective method of establishing tree seedlings (regeneration) on slopes such as these.

My study was conducted at the Tropical Forestry Initiative during the summer of 1997, with a return to Costa Rica in January of 1998 to complete my work.  My experimental design consisted of 90 one-year old pilon seedlings, Hyeronima oblonga, planted with three different site treatment methods.  The "Chop" treatment (30 trees) was designed to inhibit above-ground competition between the bracken fern and pilon seedling.  The "Plastic" treatment (30 trees) was applied in order to inhibit above-ground competition as well as to prevent the resprouting of the bracken fern.  The third treatment, "Spade" (30 trees) was implemented in order to inhibit both above-ground competition and root competition, as well as to prevent the resprouting of the bracken fern.

The response of the seedlings was used to determine the effectiveness of each treatment;  the response of the trees was measured by 1) survivorship 2) height growth, and 3) diameter growth.  These measurements were taken in July of 1997 when the seedlings were planted and then again in January of 1998 when I returned to Costa Rica.

I conducted ANOVA tests in order to compare the survivorship, height growth, and diameter growth exhibited by each treatment.  I found no statistically significant difference in survivorship between the "Chop", "Plastic", and "Spade" treatments.  There was also no statistically significant difference in height growth among the three different treatments.  However, the test of the diameter growth figures indicated that there was a statistically significant difference.  I then followed the ANOVA with a Sheffe post hoc test which determined that the "Chop" treatment showed significantly greater (p<0.05) diameter growth than the "Spade" treatment.  There was no significant difference found between "Chop" and "Plastic" nor between "Plastic and "Spade" treatments. I find these results both interesting and surprising; although I did not state a formal hypothesis for my research, I would have guessed that the "Spade" treatment would have been most effective due to the intensive removal of bracken fern roots and rhizomes.   I would like to note that these are only my preliminary results.  These results show the effects of the first six months of growth, however, I have designed this study to encompass 3-5 years.  I therefore, making any definitive statements concerning the most effective method of planting seedlings on bracken-dominated slopes is inadvisable at this time.