Festival of Science 2003 Oral and Poster Abstracts

Oral Presentations

This study will discuss the process of reaching a consensus among various non-faulty computers in a distributed computer system. A distributed system refers to a collection of computers that perform collectively on a large task by sharing resources. They achieve this by working independently but coordinating their actions with other processors.  The individual (faulty) systems can exhibit inconsistent behavior and relay conflicting information to other computers in a distributed system. It is important for the non-faulty computers to make the ‘right’ decisions despite the presence of faulty systems. This presentation will include a live demonstration of two algorithms and discuss the assumptions in the process of achieving unanimity among the non-faulty computers and identify the conditions under which this unanimity remains valid. These algorithms provide solution for Byzantine system failures in a synchronous distributed system. Byzantine Generals Problem, as described by Lamport et al. (1982), is used as a model to discuss algorithms for Byzantine failures. Byzantine Generals Problem is stated as “… a group of generals of the Byzantine army camped with their troops around an enemy city. Communicating only by messenger, the generals must agree upon a common battle plan. However, one or more of them may be traitors who will try to confuse the others. The problem is to find an algorithm to ensure that the loyal generals will reach an agreement.”

In a sandstone tidal channel facies of the Late Maastrichtian Fox Hills Formation in North Dakota, the freshwater bivalve Corbicula occur in a rich, mixed assemblage with brackish and fully marine mollusks.  These Corbicula had been assigned to at least four Linnaean species (Meek and Hayden, 1856), although it seems contrary to ecological parsimony to have four sympatric species.  If the number of species were determined, it would be possible to assess habitat separation and preferences, producing a useful tool for paleoecological analysis within the deltaic-estuarine deposits of the Fox Hills Seaway. Major revisions of the Fox Hills bivalve fauna were made by Feldmann in 1967 and Speden in 1970.  Feldmann recognized two species C. cytheriformis (M&H)  1860 and C. moreauensis (M&H) 1856, whereas Speden was unsuccessful in defining species because of lack of data.  He included morphologies assignable to C. subelliptica (M&H) 1856, C. nebrascensis (M&H) 1856, and C. occidentalis (M&H) 1856, in his Corbicula sp. A.  The original descriptions by Meek (1876) described Corbicula species primarily by characteristics of shell length, height, and width.  In our study, we are able to analyze shell morphologies using H/L and W/L ratios to assess the species separation statistically within this assemblage. The analysis suggests validity of C. subelliptica, C. nebrascensis and C. occidentalis. C. cytheriformis is a junior synonym of C. nebrascensis, and C. moreauensis is a junior synonym of C. subelliptica.  Discrimination of these species will allow progress forward recognition of habitat separation among Fox Hills Corbicula spp.

I investigated the effect of pregnancy on spatial reference memory in female Sprague-Dawley rats using a Morris water maze.  Prior research reveals a link between hormone levels during pregnancy and spatial memory.  I hypothesized that the spike of estrogen during the third week of pregnancy would hinder spatial reference memory.  Sixteen subjects were tested to establish a performance baseline and to reduce thigmotaxis.  Subjects were divided into two groups: pregnant (n = 7) and virgin (n = 9).  Subject’s goal was to find the escape platform.  The dependent measure of performance was the total time to the platform each day.  The platform position changed weekly and I compared the amount of time to find the platform within and between groups weekly.  An analysis of variance revealed no significant difference in performance between the pregnant and control groups.  All subjects learned the location of the platform.  There was a significant negative correlation between the weight of pregnant subjects and mean time to platform during the first (r = -.777, p = .040) and third weeks (r = -.873, p = .010) of pregnancy and a trend in week 2 (r = -.744, p = .055).  An F test for homogeneity of variance revealed a significant increase in variance during the third week of pregnancy, when estrogen levels spike before parturition.  This suggests that sudden increases in estrogen levels may have an effect on the ability of pregnant rats to locate the platform.

Chemical Graph Theory, a branch of mathematical chemistry that is concerned with the analysis of all consequences of connectivity in a chemical graph, will be the focus of my discussion. I will talk briefly about general graph theory in order to give an understanding of how the two subjects are connected. Graph theory is a form of mathematics that deals with the way objects are connected.  It has been utilized in several fields that include economics, physics, linguistics, computer science, biology, psychology, sociology and chemistry.  The difference between graph theory and chemical graph theory, is that with the use of the term chemical, more concepts and theorems are allowed to be relied on, as opposed to in strict graph theory, which is based primarily on formal proofs.  A graph may represent objects such as molecules, reactions, polymers, and inorganic clusters.  The basis of this subject is the presence of sites and connections of these chemical systems.  The most abundant graphs in chemical graph theory and the focus of my studies are molecular or constitutional graphs.  A molecular graph involves the connectivity of atoms when all concepts of angles and distances are removed.  Atoms are the vertices in these graphs and the edges are chemical bonds between them.  This results in the most simplistic of all chemical models.  Still, this model provides rules by which chemists may obtain predictions about the structure, stability, and reactivity of various compounds.
5:30 Shea Imhof  '03, An Integrative Investigation of the Collaborative Design Process
Faculty Advisor:  Dr. Thomas Greene
My project investigated psychological components that underlie architectural design. Although architectural design appears to evolve out of a rational process of optimization, my research suggests that design emerges from a series of human decisions. Research on the complexity of decision-making and collaboration has not fully been explored but the works of Christopher Alexander and Stephan and Rachel Kaplan support a process whereby both the design and users satisfaction improves as a result of intentional, active participation (Alexander, 1979, Kaplan, Kaplan & Ryan, 1998, Sommer & Sommer, 2002).  My approach for investigation focused on a literature review but was supplemented with a review of St. Lawrence planning projects as well as an empirical study looking at decision-making in the current science facilities planning.  In particular, interviews with project chairs provided insight into past planning at St. Lawrence and illustrated how leadership and decision-making approaches have evolved and shaped projects.  The empirical portion of my project used the method of paired comparison, which created an ordinal ranking of 7 important design criteria.  The participants were all involved in the planning of the St. Lawrence Science Facility and so were familiar with these particular design criteria.  The purpose was to determine whether weighting differences of importance exist between the design professionals, the administrative facility managers as well as faculty and student users of the proposed science facility.

My project investigated psychological components that underlie architectural design. Although architectural design appears to evolve out of a rational process of optimization, my research suggests that design emerges from a series of human decisions. Research on the complexity of decision-making and collaboration has not fully been explored but the works of Christopher Alexander and Stephan and Rachel Kaplan support a process whereby both the design and users satisfaction improves as a result of intentional, active participation (Alexander, 1979, Kaplan, Kaplan & Ryan, 1998, Sommer & Sommer, 2002).  My approach for investigation focused on a literature review but was supplemented with a review of St. Lawrence planning projects as well as an empirical study looking at decision-making in the current science facilities planning.  In particular, interviews with project chairs provided insight into past planning at St. Lawrence and illustrated how leadership and decision-making approaches have evolved and shaped projects.  The empirical portion of my project used the method of paired comparison, which created an ordinal ranking of 7 important design criteria.  The participants were all involved in the planning of the St. Lawrence Science Facility and so were familiar with these particular design criteria.  The purpose was to determine whether weighting differences of importance exist between the design professionals, the administrative facility managers as well as faculty and student users of the proposed science facility.

Tannins consumed in the diet of the eastern gray squirrel (Sciurus carolinensis) combine with protein to form tannin-protein complexes (T-PCs). Tannins inhibit the activity of digestive enzymes and decrease nitrogen absorption in the alimentary tract of gray squirrels, with reduces the digestibility of protein bound in T-PCs. In this study, we isolated bacteria from the stomach, ileum, jejunum, cecum, ascending colon, and the transverse colon of a female gray squirrel onto Brain Heart Infusion (BHI) medium overlaid with either 2% condensed (quebracho tannin) or 2% hydrolysable (tannic acid) tannin solution. In order to examine the bacteria’s ability to degrade the T-PCs, we monitored their growth on the tannic acid treated BHI (T-BHI) medium and on the quebracho tannin treated BHI (Q-BHI) medium for the formation of clear zones around the bacterial colonies. Clear zones did not form around the bacterial colonies grown on either T-BHI medium or the Q-BHI medium, however bacteria isolated from each of the sections of the gut surveyed proved to be tannin tolerant by growing on the tannin treated medium. The tannin tolerant bacteria consisted of Gram positive rods and cocci and Gram negative rods and cocci, all of which were facultative anaerobes. Some of the isolates found in the stomach, jejunum, cecum, and ascending colon possessed tannase, an enzyme that inhibits the ability of hydrolysable tannin to combine with protein. These results suggest that the gut flora of gray squirrels do not degrade T-PCs, yet some of the bacteria may assist is the digestion of diets containing tannins by prohibiting the formation of T-PCs.

During the summer of 2002, through funding provided by a Donald Rose St. Lawrence University Research Fellowship, the phenomenon of relativistic time dilation was observed using unstable fundamental particles called muons contained in cosmic radiation.  Several three hour samples of the muon flux were taken at the Mt. Washington Observatory in New Hampshire, an elevation of 6300’, using a scintillation based counter.  Given the known average muon lifetime, a non-relativistic prediction was made for the average muon flux in Canton, elevation 300’, and compared to observed results. It was found that more muons were present in Canton than the non-relativistic prediction stated, and therefore the time must have slowed down relative to a stationary observer for these muons in flight, since fewer of the particles decayed during the journey from Mt. Washington’s altitude to Canton’s altitude.

Discovery of a large, well-preserved flora at the top of the Late Maastrichtian, Fox Hills Formation in central North Dakota permits chronostratigraphic comparison with well-documented floral zones established in the Hell Creek Formation by Johnson and Hickey (1990) 240 km to the west.  More than 2900 specimens from two sites in the Missouri Valley Region of North Dakota between 70 and 45 meters below the Cretaceous – Tertiary boundary were studied.  Analysis of this remarkable leaf assemblage allows recognition of Fox Hills I, a new megafloral biozone in the Williston Basin.  Fox Hills I (FH I) is defined by Nilssonia yukonensis (11.5% of total specimens, FH1), N. compulta (5.0%, FH59), N. serotina (1.0%, FH62), Rhamnus salicifolius (4.4%, FH10), and Micronium sp. (2.1%, FH24).  Dominance by the cycad genus Nilssonia (23.2% of total) is striking.  After field and lab studies were compiled, 66 distinct morphotypes were identified.  The flora is made up of 4 cycads, 7 conifers, 2 aquatic macrophytes, 1 fern, 51 angiosperms, and 2 unidentified plant organs. Climate and precipitation analysis using the techniques of Wilf (1997) and Wilf, et. al (1998) have been preformed.  From these leaf margin analyses, the mean annual temperature of FHI was between 19.04 and 20.17 degrees Celsius, and the mean annual precipitation was 171 cm (+73, -52).  These data coincide with a warming trend that occurred approximately 0.2 million years before the Cretaceous – Tertiary boundary (Wilf, et. al, 2003). This new climatic information, coupled with the megafloral analysis provides a better understanding of the Latest Cretaceous geologic history in North Dakota.

The wise psychologist will regard literature as a vast storehouse of information about human experience, and will not neglect to draw from it what he can. (William McDougal, An Outline of Psychology, 1923). This paper presents the results of an on-going group research project, the purpose of which is to identify broad cross-cultural patterns in the depiction of female and male protagonists and antagonists.  Results are based upon a quantitative content analysis of 658 randomly selected folk tales from 49 different culture areas from all around the world and 240 plot and character summaries from western canonical literature.  Analysis of data reveals salient trends of characterization across the sample in parameters associated with age, levels of physical attractiveness, frequency of representation as the main character, marital status, mating preferences, motivation, level of activity, personality descriptors, propensity for physical heroism, and patterns of altruism. The search for these patterns was guided by evolutionary theory and the findings are consistent with previous research on patterns of altruism, sex differences in mate preferences, sex differences in reproductive strategy, and differing emphases on male and female physical attractiveness.  Moreover, the finding of salient patterns of characterization across centuries, continents and cultures is consistent with evolutionary theories of human behavior and psychology and inconsistent with strong constructivist models.  World literature, especially originally oral literature, represents a vast and neglected repository of information that researchers can use to more precisely map the contours of human nature.

The purpose of this investigation period was to further delve into the phytochemical constituents of the Aristolochia salvadorensis plant.  Indigenous peoples in El Salvador utilize root-derived teas brewed from this plant for medicinal purposes.  The hexane soluble materials of the root of the plant comprised the focus of the investigation.  Earlier work in this lab concentrated on isolation and identification of aristolochic acids and lactams. The hexane extractables yielded a complex mixture of terpenes.  Capillary GC-MS revealed the known compounds aristolene, ?-gurjunene, ?-gurjunene, ?-guaiene, 1-tetradecene, 1-pentadecene, 1-octadecene, alloaromadendrene, 1-dodecene, docosene, copaene, (+) sativene, ?-muurolene, ?-muurolene, (+) ledene, cadinene, ?-gurjunene, and ?-elemen. Further,  a previously undocumented sesquiterpene with molecular weight of 204 g/mole was and chemical formula, C15H24 was isolated. Its structure and relative stereochemistry was determined by use of mass spectrometry, 1H, 13C, and various correlative hetero-nuclear and homo-nuclear NMR data.  This novel sesquiterpene (see below) was identified as pacifigorgia -7,10-diene.

Salvia divinorum is a hallucinogenic plant used by the Mazatec Indians of Mexico for traditional healing ceremonies.  The active constituent, Salvinorin A, has been shown to induce profound hallucinations, however the biological mechanism for this action is unclear.  Most recently, a study has shown that Salvinorin A has a high affinity for the k-opioid receptor.  The purpose of this study was to evaluate the antinociceptive effect of Salvinorin A.  Specific receptor antagonists were injected intrathecally (i.t.) to block the receptors.  Salvinorin A was then administered i.t., and the tail-flick response was used to assess antinociception.  In concentrations of 13.9 – 23.1 nmol, mice demonstrated a significant increase in tail-flick inhibition compared to control trials.  Furthermore, Salvinorin A induced tail-flick inhibition is blocked by the k-opioid receptor antagonist nor-binaltorphimine (nor-BNI), but not by the m-opioid receptor antagonist b-funaltrexamine (b-FNA).  These data suggest that Salvinorin A is the first non-alkaloidal analgesic compound, and is mediated by the k-opioid receptor.

Poster Presentations

In the United States, unintentional injuries are the leading cause of death among children under the age of 18.  Several studies have investigated the effectiveness of interventions that promote, or regulate, the use of safety equipment to prevent injuries, or to decrease their severity.  Previous studies have shown that children are able to distinguish varying degrees of risk, and that tolerance for physical risk taking can change as a function of safety equipment usage.  Research findings have suggested differences in risk tolerance, due to differences in risk perception, as a possible reason for compensatory behaviors.  For example, children who wear bicycle helmets may feel that they are more protected, leading them to modify their behavior, by taking more risks.  The present study was designed to investigate how safety equipment, such as bicycle helmets, knee pads, and life jackets, effects the relationship between risk perception and risk tolerance in situations that are common in early adolescence.  Based upon Wilde’s Risk Homeostasis Theory, it was hypothesized that participants’ risk perception would be lower in situations with safety equipment.  Thus, their tolerance for risk would be greater in these situations than in similar situations without safety equipment.  The participants were fourth, sixth, and eighth graders from a rural, public, middle school.  All children completed a self-report questionnaire that measured risk perception and risk tolerance in scenarios with and without safety equipment.  The data are currently being analyzed.

This study is focused on two objectives: breeding behavior (scrape use) and space use patterns (habitat use) of a free-ranging population of white-tailed deer (Odocoileus virginianus) in an agricultural landscape.  These are both important factors to understanding white-tailed deer biology, and therefore can be very important in the future management of white-tailed deer populations.  Passive infrared triggered cameras were used to record the activities at the scrape sites.  The pictures from each camera were used to determine the; sex ratio of visitors at scrape, number of different male visitors; time of day visited, and approximate age distribution of males using the scrape.  Statistical analysis was done using a chi-squared test for sex ratio.  In order to evaluate the patterns of space use by white-tailed deer, I used the GPS unit and followed and recorded the habitat type in which each main trail was located in.  Also collected were the locations of old rubs and scrapes, budding activity and bed locations.  I used GIS archview to map out the trails and different behavioral features collected.  From this statistical analysis was done to determine the most used habitat types.  Results indicate that scrapes are visited by a number of different males, primarily under the cover of darkness and where as female visits took place during day light.  It is also apparent that white-tailed deer prefer habitat types with protective cover and browse, such as hemlock and cedar, as well as mixed hardwood and conifer stands.  This suggests that we need to have a good mix of habitat types to support the white-tails needs year around.  The use of scrapes by both males and females demonstrates there use as a means of communication between the sexes and is therefore important in the breeding process.

This project looks at the effects of habitat fragmentation on population size and density of Peromiscus maniculatus and Peromiscus leucopus from data collected during the summers of 2001 and 2002. The project was conducted on the St. Lawrence University Golf Course and on adjacent, university-owned woodland, the Kip Trail.  Data was collected from five fragmented “tree island” grids of varying sizes on the golf course as well as from five matching “mainland” grids in the unfragmented habitat on the adjacent woodland.  This was done to measure the effects of habitat fragmentation on the fragmented islands in comparison to the unfragmented sites.  The dimensions of each trapping grid (trap spacing and the total number of traps) varied depending on the size and shape of each golf course island.  Using mark and recapture techniques we were able to collect the data necessary for the use of different population estimators.   To analyze the data I used Popan software.  Popan provides an estimate of each population size for each individual grid and allows you to work with closed and open populations.  This program computes population size that can then be used to determine population density.  Previous research shows that population density is greater in fragmented sites but over all population size tends to show a decreasing trend.  Much of what I have observed and recorded in our data follows similar trends.

Several cemeteries in the Canton, NY area are thought to contain a significant number of unmarked graves. This study examined three local cemeteries for evidence of burial features. The County Home was a commune for residents that were economically challenged. Many passed away and were buried in currently unmarked graves on the grounds. The actual conditions of the burials are largely unknown, meaning a coffin may or may not have been present for entombment. Ground penetrating radar (GPR) offers the potential for delineating individual or mass graves owing to patterns of soil disturbance. GPR surveys at this site did not provide conclusive evidence for individual or mass graves. In order to contrast the conditions of the County Home Cemetery, additional surveys were conducted at the Silas Wright and Miner Street Road cemeteries. Here the burial conditions are better documented and marked and GPR surveys resulted in the delineation of several identifiable grave locations.

The distribution and composition of zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussel populations are examined from navigational buoys located throughout the St. Lawrence River.  Populations on each buoy were examined by the density of mussels, their size, and the relative proportions of each speices.  This data was intergrated into a geographical information database to allow spatial examination for trends.  Preliminary results show that population densities are the greatest in the upstream section of the river, near Cape Vincent, NY and appear to drop drmatically near Alexandria Bay, NY.  Also, quagga mussels appear to dominate the upper regions of the river, while zebra mussels may be more dominant in the lower sections, near Massena, NY.

Previous studies have shown that the locus coeruleus (LC) subserves a variety of behavioral functions including attentiveness, central pain processing and more recently central respiratory control. We hypothesize that the other functions ascribed to LC predominate over its putative role as a central chemoreceptor site. To test this hypothesis, we attempted to dissociate the effects of pain processing from central respiratory control. The role of the LC in respiratory control is currently being evaluated in another study (Mary Schwab and Jaime Gallgher) by examining the respiratory effects of carbon dioxide following focal, neurotoxic lesions to the LC.  In this study, we investigated the effects of cold-water swim on tail flick latency as a measure of pain threshold following LC lesioning.  The descending pain pathway involves several pontine and medullary sites including the paraquaductal grey, parafasicular nucleus, raphe magnus and locus coeruleus.  The LC modulates pain processing using two pathways.  First, it is responsible for opioid release into the dorsal root of the spinal cord.  Second, it has inhibitory projections to the parafasicular nucleus, which inhibits opioid release from paraquaductal grey.  Previous studies have shown that lesioning the LC decreases tail flick latency as a result of decreased opioid release arising from damage to the LC.  This study found that LC lesioning actually increases tail flick latency, most likely arising from the removal of the inhibitory input to the parafasicular nucleus.

Tuning fork based lateral force feedback is an effective tip-to-sample distance regulation mechanism in near field scanning optical microscopy.  The oscillating piezoelectric potential produced by the tuning fork is proportional to the amplitude of motion of the fiber and is used to keep the probe close to the sample surface.  The tuning fork can be vibrated either mechanically or electrically.  Additionally, the tuning fork signal can be measured using a voltage preamplifier or a current preamplifier.  Thus, there are four possible circuits that can be used to measure the tuning fork signal: a voltage preamp with a mechanical drive (VPMD), a voltage preamp with an electrical drive (VPED), a current preamp with a mechanical drive (CPMD), or a current preamp with an electrical drive (CPED).  The experiment presented here examines which circuit yields the best signal to noise ratio in the tuning fork signal.  The average measured signal to noise ratios for the VPMD, VPED, CPMD and CPED circuits were comparable at 114, 59, 81 and 81, respectively.   While the average S/N ratio of the VPMD circuit is best, it is not dramatically different from the S/N ratio of the current preamp circuits.  Therefore, due to the practical advantages of the CPED circuit, it was concluded that the current preamp with an electrical drive is the optimal preamplifier circuit for near-field scanning optical microscopy tuning fork based feedback.

The uses of Brosimum alicastrum Sw. (Moraceae)have been obtained from published studies and surveys of scientists currently working in Mesoamerica, South America, and the Caribbean. The seeds of this tree are known to have been consumed by the ancient Maya similarly to corn, and it has been postulated that the forests near ancient Maya archaeological sites may have been managed for their production. One result of this practice may be the dominance of this tree in Mesoamerican forests. Based on these assumptions we suggest that the uses of B. alicastrum are of greater importance to humans in Mesoamerica than in South America, and that this is perhaps the reflection of the past.  First, a review was conducted of secondary sources.  Books, journal articles and selected websites that dealt directly with B. alicastrum were analyzed first, followed by any in which the species was mentioned as part of a larger study.  Second, a nine-question questionnaire was created and distributed via e-mail to biologists, ethnbotanists, ecologists and other researchers who had and are conducting research in Latin American tropical forests and other environments that are conductive to the growth of B. alicastrum.  Whether future research on this is done through more literature reviews or field research, B. alicastrum is still a rather obscure crop with an incredible potential for interpretation, analysis, and importance, one that should not be overlooked but rather appreciated as a crop which may have determined the survival of the Maya through time.

Dibromoacetic acid (DBA) has been shown to cause adverse reproductive effects in both males and females. Chronic exposure to DBA in nonpregnant adult female rabbits was associated with a reduction in the population of primordial follicles, but did not effect patterns of follicular growth or the ovulatory response. It may be that the critical window for DBA exposure is during the period of primordial germ cell migration and/or follicular formation. To investigate the timing of DBA toxicity, follicular populations in female neonatal rats exposed to DBA were examined. Four groups (n=5 per group) of female Sprague-Dawley rats were gavaged daily with 0, 1, 5, or 50 mg DBA/kg body weight beginning in utero from gestation day 17 through postnatal day 7. Maternal weight, pup weight, litter size and sex ratio did not differ across treatment groups and there were no differences in major organ weights noted at necropsy. Ovaries were fixed in 2% gluteraldehyde and processed for histopathology. Tissue blocks were serially sectioned at a thickness of 8 µm. Every eighth section was stained and used for morphometry. All healthy follicles within a section were categorized into one of five types: primordial, primary, small preantral, large preantral, or small antral, and the area of section measured. Follicular populations at all stages of development did not differ among treatment groups and there was no difference in number of atretic follicles or necrotic oocytes. Thus, exposure to DBA during the period of follicular formation does not effect follicular populations in neonatal rats.

The locus coeruleus (LC) has been found to have multiple roles including pain processing, stimulating arousal, and anxiety disorders.  However, the role that the LC plays in central chemoreception is not clear. To determine what contribution the LC has on eupnic and hypercapnic breathing bilateral lesions of the LC were performed to assess the ventilatory effects to room air and hypercapnia using the whole body plethysmograph.  Respiration of animals with bilateral injections of either artificial cerebral spinal fluid (ACSF), 5 mM, or 10 mM kainic acid was measured using a progressive 0-8%, graded (by 2%) CO2 tests for days 1-7, and 14 following the surgery.  No significant changes in expired minute ventilation (VE), tidal volume (TV), or frequency (f) were found in either eupnea or hypercapnia compared to presurgical baseline data in lesioned animals.  Following physiological testing confocal microscopy was used to determine the number of tyrosine hydroxylase (TH) positive cells in lesioned and control animals.  It has been found that there is a significant decrease in TH positive cells in animals treated with 5 mM and 10 mM kainic acid compared to control animals.  This data suggests that the CO2 sensitivity of ventilation in lesioned rats is not significantly different from that in non-lesioned animals.  We concluded that the LC plays an important role in the brainstem, however central chemoreception is not a primary function.

Photochemistry of aromatic compounds is of interest to researchers because of its complexity and reaction pathways that have not been studied.  Investigations of possible reaction mechanisms could shed light on the remediation of environmental wastes of aromatic compounds that are found in aquatic environments. This undergraduate research focuses on the photocatalytic reactions of two aromatic compounds, benzotriazole (BTA) and benzotriazole-5-carboxylic acid (BCA). The photocatalysis of BTA and BCA in the presence of TiO2 was conducted in a photolysis chamber.  A metal ion was added to study the possible effects of metal-ligand complexation on reactivity of the photocatalytic reactions.  The reactions were monitored using a UV/vis spectrophotometer.  GC/MS was employed for product analysis and proton-NMR was used to study metal-ligand complexation effects. Based on the investigation, it was determined that a hydroxyl triazole intermediate was formed during photocatalysis of BTA.  A different reaction pathway is proposed for photocatalysis of BCA.

Gap junctions are important in generating rhythmic brain activity and are present in respiratory related regions of the medulla including the pre-Botzinger complex, nucleus ambiguus motorneurons, the locus coeruleus, nucleus tractus solitarius, and retrotrapezoid nucleus (RTN). Using chronically instrumented rats in which the RTN was cannulated we focally perfused either the gap junction inhibitor carbenoxolone+ artificial cerebral spinal fluid (aCSF) or aCSF alone. Unilateral blockade of gap junctions in the RTN of conscious rats decreased expired ventilation (VE) ~30% at all CO2 levels tested (0-8%) in young, adult rats (~8-10 weeks) by decreasing tidal volume (VT). In contrast, perfusion with aCSF had little effect on VE, VT or breathing frequency during progressive hypercapnia in all animals tested. To evaluate the role of electrical coupling in older animals we unilaterally cannulated the RTN of  rats ~11-12 weeks of age and 13-16 weeks of age and repeated the experiment. The decrease in VE after gap junction blockade that was apparent in younger animals was not evident in 11-12 week old animals and the effects of carbenoxolone reversed (i.e. increased ventilation) in rats 12-14 weeks of age. We conclude that the role of electrical coupling in respiratory control in the RTN is biphasic, suggesting a changing role of gap junctions in the respiratory circuit in adult animals.

From early February to late March of 2003, a study of the winter habitat and range of the North American Porcupine (Erethizon dorsatum) was conducted at the Indian Creek Nature Center in upstate New York.  A porcupine’s preference for food and their average home range vary with the seasons (Griesemer et al., 1998). Snow trails created by porcupines and used continuously for travel throughout the winter, were used to located den sites and feeding trees. These trails, along with located dens and feeding trees, were mapped via a GPS system. This enabled us to determine their preferred habitat, a forest composition of hemlock and beech trees, and also their average winter home range. Active den sites were most commonly found in beech trees. The average diameter at breast height (dbh) of these den trees was 7 feet while the average height of the den trees was 57 feet. This information will serve to educate the nature center’s staff on the location and activity of the porcupines during the winter months, which could be relevant to park trail management and forest use.

This study examined the effect of management style on subordinate time allocation.  I was interested in the relationship between style and  1) managers’ opinions of how subordinates use time,  2) the relationship between managers’ time expectations and subordinates’ expectations, and  3) how subordinates actually allocate work time. Twenty subordinates and six mangers in a New York manufacturing firm responded.  Participants were drawn from sales, logistics, vice president, marketing, design, and finance divisions.  Subordinates first evaluated managers on the Leader Behavior Description Questionnaire, a commonly used leadership measure, in order to determine the manager’s emphasis on initiating structure and consideration.  Subsequently, subordinates reported how much time they would prefer to spend and how much time they actually spent on 12 s work activities.  Their respective managers also estimated actual time spent on the 12 activities.  I focused on activities that were not directly related to traditional productive tasks. The data revealed that the opinions of even high consideration managers  had little to do with either the time their subordinates desired to allocate to different tasks or the actual time expended on those tasks.  Predictably, managers differed from their subordinates in valuing time, but subordinates also showed variability, sometimes desiring more time than they used, and sometimes using more time than they believed they needed.  The results suggests that time allocation is misunderstood in the working environment and support the need for clearer communication between managers and their subordinates.

When neurologically healthy individuals attempt to bisect a horizontal line as accurately as possible, they tend to show a very slight leftward bias.  This is referred to as the Pseudoneglect Effect.  One hypothesis proposed to account for this leftward bias is the Attention Recruitment Theory.  It suggests that errors in bisection are due to a bias in attention allocation toward the left visual field.  This bias supposedly occurs because the right hemisphere is more engaged in spatial ability tasks such as line bisection.  Therefore, when bisecting a line an individual would show a leftward bias due to the additional attention being given to the task by the right hemisphere.  The present study was conducted to determine if the pseudoneglect effect could be affected by manipulating the placement of the functional fovea (a 2-4 degree circle encompassing the physiological fovea where visual acuity is at its best).  This was accomplished by placing either 1 or 2 small black dots near the endpoints of an 83 mm horizontal line.  A total of 29 right-handed subjects were given 7 test stimuli and 6 distractor stimuli.  For some of the test stimuli the attention recruitment and functional fovea theories would predict the same bias in bisection to occur.  For other stimuli, however, the two theories would make opposite predictions.  The results indicated that when placed in competition with each other, the functional fovea theory clearly had more of an influence on line bisection tasks than did the attention recruitment theory.

Just as people can possess different personalities, they can also display different work styles.  An individualist work style places a priority on accomplishing the individual's goals.  A collectivist work style emphasizes mutual benefit, social approval, and working together with others towards a common goal. Participants were 40 students enrolled in an Industrial/Organizational Psychology class.  An Individualist-Collectivist survey was developed primarily for this study.  First, 25 items were generated from a literature review. Cluster analysis intended to verify the items proved unsatisfactory, so a set of 20 more items were added to refine the constructs.  Scores from the refined scale were used to separate participants into Individualist, Collectivist or Diverse groups of 3-5 students each.  Over a six-week period these groups completed a series of four team projects.  Two projects favored an Individualistic work style, whereas the other two favored a Collectivist approach.   We hypothesized that the different tasks would favor individuals who expressed a compatible style but that the relative value of a diverse approach would manifest itself most clearly near the end of the study after group rapport had matured.  The effects of style were evaluated through both individual and group measurements of response accuracy, creativity, and satisfaction with the group.

The preparatory science program of the Terrestrial Planet Finder (TPF) of NASA’s Space Interferometry Mission (SIM) includes a complete, systematic study of nearby stars (Nstars).   Our work has been part of the Appalachian State project headed up by Richard Gray (App. State) in cooperation with Chris Corbally (Vatican Observatory) and Robert Garrison (U. Toronto) investigating stars within 40 pc (~150 ly) with surface temperatures warmer than 3500K.  Since they are distributed all over the sky, observations of these stars has required the use of telescopes in North Carolina, Arizona, Chile, and Canada. In this project, we participated in observations at the University of Toronto’s David Dunlapp Observatory (DDO) in Toronto, Canada, and the Cerro Tololo Interamerican Observatory (CTIO) in La Serena, Chile. We have also worked at removing the effects (primarily extinction) of Earth’s atmosphere from the spectra obtained at DDO so as to flux calibrate them at each wavelength to insure accurate spectral classification and analysis.  This requires characterizing the effect of the atmosphere at each wavelength for all observing angles between the horizon and zenith.  Observations of a spectrophotometric standard star at a variety of angles were systematically compared to the known flux of that star at each wavelength to obtain the atmospheric extinction curve for the Toronto sky.  The model was then applied to each observed program star to calibrate its spectrum.

There is increasing evidence that glial cells play an important role in information processing in the medulla.  Glia can modulate central respiratory control regions of the medulla.  This study examined the density and pattern of glial cells present in the medulla at various developmental stages.  I hypothesized that as the animal aged, there would be a proliferation of glial density, specifically in the RTN/NTS regions.  The subjects used were Sprague-Dawley rat brains (slices 40 microns thick).  After being rinsed in a series of PBS-Triton solutions and non-specific binding blockers, a primary GFAP antibody was applied to the slices.  This antibody targeted epitopes on the Glial fibrillary acidic protein present in all glial cells, regardless of age.  A secondary fluorescent marker antibody was then added to stain GFAP positive cells.  Preliminary data suggest that the hypothesis is supported, in that all visual results suggest that glial density is age-dependant.

I caught and radio-collared four North American porcupines (Erethizon  dorsatum), and used both radio telemetry and triangulation to assess their non-winter home range size. I conducted my study from June of 2002 through October of 2002 and used the Kip Tract as my study area. I used Archview 3.2 to assess the kernel home range size of the porcupines using the telemetry data points that I collected. I also conducted a study on the winter home range size of porcupines using a couple of different techniques which included using a GPS unit to map snow trails leading away from known porcupine dens and using the radio telemetry equipment to track the porcupines to specific sites within the study area. After analyzing my non-winter data I compared the home range sizes of the porcupines between the two different seasons to see if there were expected differences between the data, where the non-winter home range size would be larger than the winter home range size. Also, for the non-winter home range I did a compared the home range size of female porcupines verse male porcupines to see if there were any differences.

The Capital Asset Pricing Model (CAPM), developed in 1964, was a breakthrough in mathematical finance.  The model has two uses.  The first goal of the CAPM is to create a portfolio that maximizes the return for a given level of risk or to organize a portfolio that minimizes risk for a specific return.  The second use is to estimate expected returns on investments that have not yet been traded.  My research has focused on understanding the economic background of the CAPM, how it was developed and some of the math behind is development/application.

My experiment was designed to see if detectors other than the eye could measure Rayleigh scattering to the same power of –4.  My results are not consistent with theory.  According to theory, Rayleigh scattering changes the intensity of light proportional to the wavelength by a negative power to the fourth.  My results using the video recorder indicate that at 45 degrees from the sun the intensity is changed by a power of –1.0685.  For 90 degrees from the sun the intensity is changed by a power of 0.2876.  For 135 degrees from the sun the intensity is changed by a power of –0.0861.

Our study examines how the death of a parent impacts the family situation and the potential for resiliency in adolescents.  Financial burdens initiated by the loss of resources from the deceased parent force economic decisions to be made by the surviving parent.  Parents must allocate time efficiently in order to be available to their children to aid in the coping process.  Three economic strategies may be employed: finding other income sources, purchasing market substitutes, and relying on social networks.  We hypothesize adolescents will cope most effectively when their surviving parent utilizes appropriate strategies in order to create ample time with their children.  Our study also considers how socioeconomic status, the parent’s gender, and his/her social network can mediate the surviving parent’s decision and how the adolescent’s adjustment may be influenced by variables associated with the death, the parent’s functioning, the child’s social network, and sibling presence.  Participants who lost a parent between the ages of 11 and 17 were recruited over a two-week period and will be interviewed for two hours about their experience.  Approximately 25 subjects will be interviewed.  The qualitative data will be analyzed for general themes, and compared and contrasted to a proposed model.

This study examined the structure of subgroups within the social network of the St. Lawrence University senior class of 2002 as well as the members of the science faculty and staff. Data was collected last year by Aleksandra Portnova, which depicted the social relationships between seniors. She carried out a survey where she asked 385 seniors to indicate other seniors whom they knew and had spoken to during the Spring 2002 semester. She collected data from 271 students, which was stored as an adjacency matrix. Aleks was interested in including as many members of the senior class as possible so she considered any mention of one student by another as a mutual acquaintance; in an effort to clean the data and make the data set size more manageable, I reinterpreted the raw data so that a mutual acquaintance required both students to mention each other. The final “two-way" data set was 70.4% of the original. Cliques in this graph were then found using the Bron and Kerbosch algorithm, which reported 30,215 cliques, many of which were overlapping. This algorithm was originally implemented in Algol 60; I wrote a similar algorithm in C++ programming language and will compare the results of running both algorithms. These results show that although the senior class of 2002 was very well connected (according to Aleksandra’s study), the number of cliques was less than expected – probably because of the conversion to two-way data. A similar study was performed on the science faculty and staff data set.

Numerous studies have demonstrated that peer groups can influence the likelihood that individuals will perform risky behaviors.  This study examined how the presence or absence of safety equipment modified the influence of peers in risk taking situations.  An activity Questionnaire was given to 72 children from the fourth, sixth, and eighth grade.  Males and females were represented equally and 12 from each grade filled out the questionnaire.  Children were asked to look at pictures of other children doing common activities such as biking, rollerblading, and skateboarding with and without safety equipment.  They were then asked a series of questions about the activity, including questions about peer influence.  High-risk activities, those performed without wearing safety equipment, were expected to have a lower estimate of actual participation, but a higher correlation between peer influence questions and participation rates.  Therefore, low risk activities were expected to have higher estimates of actual participation but lower correlation between peer influence and participation rates.  The data are currently being analyzed.

Last summer, I participated in a NYSEP (New York Science Education Program) summer research project aimed at isolating and characterizing genes involved in fruiting (the development of mushrooms) in the fungus, Schizophyllum commune. Previously, Professor Horton et al (Union College) isolated a gene, FRT1 that was shown to induce fruiting in S. commune. Using FRT1 as bait in a yeast two-hybrid assay (a genetic method of identifying interactions between proteins), other genes that were thought to be involved in the fruiting process were isolated. One of the genes identified from the yeast two-hybrid assay was a sugar transporter (ST) gene. The task thereafter was to find out whether and how ST was involved in the fruiting pathway. The first step was to clone the gene into a vector to form a plasmid. The ST gene would then be knocked out and the plasmid transformed into the S. commune cells to see if and how disruption affected the fruiting process. Last summer, the ST gene was successfully cloned into the vector to form the plasmid. Different ways to knockout the gene were, and still are, being investigated. Work on this gene would continue with other research fellows in the fall of 2002. Other projects undertaken in the laboratory included using the FRT1 and ST genes as bait to find other genes that are involved in the fruiting pathway.

A suite of four groundwater wells were installed in a linear transect along the greatest topographic gradient feeding into the Little River in the cleared field at the intersection of Rt. 68 and Pike St. in Canton, NY.  Each of the wells contained a nest of four piezometers installed at depths of 40, 30, 20 and 10 feet.  This well setup allows for hydraulic head variations to be measured vertically as well as horizontally in order to determine groundwater flow paths beginning in the recharge zone and terminating in the discharge zone.  Cores obtained from drilling were analyzed for soil hydraulic properties.  Preliminary assessment of these cores showed a sandy aquifer approximately 4.5 meters thick at the base of the slope confined at the base by an impermeable, highly pressurized gravelly till aquitard with a significant clay fraction, and at the surface by impermeable clay aquitard likely of Glacial Lake Iroquois origin.  The aquifer thinned considerably upslope.  Texture was determined first by sieving the cores to determine the coarse fraction, and then by a hydrometer test using the Bouyoucos Method to determine the clay fraction.  Data obtained by these tests were used in modeling groundwater flow using MODFLOW software to determine flow paths and rates. This project represents a portion of a larger study to quantify water pathways in the Little River Basin.

This study explores the effects of training attentional abilities in female college students through use of neurofeedback training (NFT). Ecological validity was seen as paramount in the design of this study. Validation of the Peak Achievement Trainer™ (PAT) through use of the previously established Intermediate Visual and Auditory Test of Attention (IVA) was one of the primary goals. This study presents novel methodology in neurofeedback research by introducing an active placebo and by using mood state, measured by the POMS test, as a covariate. Dependent measures included self-efficacy, concentration scores from the PAT, and several attention quotients from the IVA. 15 female college students (mean age: 20.3) where randomly assigned to experimental, active placebo and control groups, each tested three times for each dependent variable. The independent variable was type of feedback, with the experimental group receiving regular NFT, the placebo group receiving partially related feedback, and the control group receiving no NFT. Experimental and placebo groups completed 8 neurofeedback sessions within a 6-week period. Sessions were scheduled according to participants’ morningness and eveningness scores determined by the Owl/Lark questionnaire. It was hypothesized that with mood state score as a covariate, participants in the experimental group would score significantly higher on PAT and IVA measures. Preliminary repeated measures ANCOVA revealed the following expected trends: The experimental group showed mean increases on scores for PAT and IVA over both control and placebo groups. Alternatively unexpected trends included: No significant differences for scores on the self-efficacy test.

The pollination biology of Aristolochia salvadorensis (Aristolochiaceae), an endemic medicinal plant of El Salvador was studied during the summer of 2002, the rainy season in El Salvador.  Plants with flowers were observed throughout the day, when the insects are active.  Insects visiting the flower were captured and photographed using a Nikon digital camera mounted on a Leica stereomicroscope.  Results indicate that, unlike several other Aristolochia, various invertebrates may contribute to the pollination of the species, among them are flies, beetles and ticks.  These kinds of studies are important in the conservation and management of medicinal plants.

This study investigated whether gap junctions in the CA1 region of the hippocampus influence spatial learning in conscious Sprague-Dawley rats. Subjects were randomly assigned to an intact control group, a control group receiving artificial cerebral spinal fluid (ACSF) or a carbenoxolone (CBN; 300 µM) treatment group. ACSF or ACSF+CBN were perfused into the CA1 region via push-pull pump at 0.06 ml/hr for 1 hour. CBN has been shown to reversibly abolish gap junction-mediated coupling. We hypothesized that disrupting gap junction coupling with CBN would increase the amount of time rats needed to learn the location of the platform in the Morris water maze as compared to ACSF-perfused control rats. Rats were tested for four trials per day for five consecutive days. CBN rats were slower to learn the location of the platform and were slower to the platform than the ACSF rats during the five days of testing. There were no differences between ACSF rats and intact controls. These findings suggest that gap junctions in the CA1 region of the hippocampus are involved with spatial learning and that CBN treatment decreases both the acquisition and retrieval of spatial information the rat in the water maze.

Fragmentation of animal populations may result in loss of genetic variation due to a decrease in gene flow between populations. After fragmentation, genetic drift within populations is expected to increase, further decreasing the level of genetic variation and increasing the risk of population extinction. Thus understanding the degree to which habitat fragmentation alters population genetic structure is critical for making informed management decisions. Microsatellites, sequences of DNA containing a variable number of tandem nucleotide repeats, have been used to determine population genetic variation on local levels for a variety of purposes. I am investigating the effects of habitat fragmentation on population genetic structure in two small mammal species, white-footed mice (Peromyscus leucopus) and deer mice (Peromyscus maniculatus) using microsatellites. I will empirically test the hypothesis that with little movement between fragmented habitat patches, subpopulations of Peromyscus on the St. Lawrence University golf course will be genetically distinct from one another and when compared to Peromyscus individuals that inhabit an identically shaped, unfragmented habitat. Because of little movement, I expect that on the golf course, gene flow from outside each isolated population will be infrequent, reducing the number of alleles present in the island populations and allowing subpopulations to segregate genetically over time.

The objectives of this undergraduate research project are centered on developing a mass balance model for the Little River watershed.  The model was built in the STELLA computer program.  In order to generate the environmental data needed for building the mass balance model, water and air monitoring have been conducted with various chemical sensors and analytical methods.  The mass balance model that is being developed can be used to determine the steady state conditions that the watershed would reach after a change in the input or output of some chemical constituents. To collect water quality data, Vernier ion selective electrodes were used during several canoe trips.  Four ionic species found in the water were included in the mass balance model; Ca2+, NH4+, NO3-, and Cl- ions.  To collect ambient air quality data, a cyclone/denuder/filter pack setup was employed to collect gaseous and particulate chemical species.  Gravimetric analysis, ion chromatography, and scanning electron microscopy were used to obtain information on mass concentration, acidic and basic gases, ionic species, and trace metals in ambient air.  The experiments developed were adapted into general chemistry and instrumental analysis laboratory courses.  After the model is finished, students and professors can use the model to study the environmental quality of the Little River Watershed.  Professors can use the model to discuss the principles of mass balance modeling and the behaviors of naturally occurring constituents

The lakes of northern New York have important recreational and commercial uses that depend on high water quality and healthy biological resources. However, many of these water bodies are stressed due to human impact (e.g., acid rain, nutrient enrichment, toxins). The goal of this summer research project was to start a long term assessment and comparison of the environmental conditions of Black Lake and Cranberry Lake. Using GIS, the watersheds were characterized in order to explain some of the environmental conditions within the lakes. Black Lake had a pH of 8-8.7, most likely attributed to the large percentage of calcitic bedrock and agricultural land surrounding the lake. Cranberry Lake, which lies on primarily igneous bedrock and is surrounded by evergreen forests, had a pH of 6.4-7.4. Their watersheds composition also indicates why Black Lake had conductivity 10 times higher than Black Lake. An index of productivity, measured by secchi depth, showed that Cranberry Lake was highly eutrophic, 1-2.5 meters, whereas Cranberry Lake was more mesotrophic, 3.7-6 meters. Black Lake’s high level of productivity makes it an excellent lake for the fish community and brings many fishermen during the summer. Furthermore plant nutrients (N,P) are also being analyzed to help explain productivity levels. Other physiochemical conditions were measured to assess lake stratification and bottom oxygen depletion. The final component of this study was to describe biological factors such as pelagic chlorophyll a and zooplankton densities as well as littoral macrophytes diversity and benthic clam populations.

The Ponzo illusion is comprised of two horizontal lines of equal length encompassed by an angular shape.  The horizontal line closest to the apex of the angle is commonly perceived as being longer than the line closest to the base of the angle.  The purpose of this study was to investigate whether the perceived length of the horizontal lines could be altered by manipulating the placement of the functional fovea (a 2-4 degree circle surrounding the physiological fovea where visual acuity is optimal).  This was done by using black dots that were placed in strategic locations near the endpoints of some of the horizontal lines.  The 33 participants were first asked to determine whether they perceived the top or bottom horizontal line as being longer in each of the 4 test and 4 distractor Ponzo figures.  Having done this, the participants then indicated how much longer the line appeared to be compared to the other line by making a slash mark on an answer sheet.  The results indicated that either altering the top or bottom line could significantly reduce the strength of the Ponzo illusion.   In addition, the reduction in the strength of the illusion was found to be symmetrical.  The conditions in which the top line was perceptually “shortened” or the bottom line was perceptually “lengthened”, produced similar decrements in illusion strength.  Furthermore, it was even possible to completely eliminate the normal illusion effect by altering the placement of the functional fovea for both lines simultaneously.

The goal of this project is to use Monte Carlo simulation to investigate the clay mineral-solution interface, paying particular attention to tetrahedral charge sites. Negative charge sites in montmorillonite are due to ion substitution (Al3+ for Si4+ in the tetrahedral layer). In our model, tetrahedral Si carries a partial charge of +1.2 e, rather than the full oxidation charge of +4 e. Examining the effect of the tetrahedral Al charge on interlayer structure will allow us to develop a more accurate model of clay-solution interactions. When the tetrahedral charge was concentrated on the Al ion, we found that the interlayer Na+ was attracted to the surface. With the tetrahedral charge concentrated on the surrounding O atoms, Na+ moved away from the surface. We also studied other clays that have negative charge exclusively in the tetrahedral layer (e.g., beidellite and vermiculite).

A ca. 1300 to 1150 Ma K-feldspar megacrystic gneiss occurs as an elongate lens within multiply-deformed amphibolite to granulite facies metasediments in the Adirondack Lowlands of New York. This visually striking rock is texturally complex and contains textural elements implying magmatic crystallization and metasomatism, as well as metamorphic recrystallization. The body is locally strongly deformed and possesses a foliation of varying intensity made up of discontinuous alternating felsic and mafic laminae. Highest strain levels occur within the marginal zones where significant grain reduction has occurred. In these areas, megacrysts lie in the foliation plane and recrystallization tails are prominent. A few exceptions lie oblique to the foliation plane, seemingly truncating the gneissic foliation, suggesting the possibility of post-fabric growth.  Isolated examples of myrmekite in the marginal zones may be strain induced. In lower strain areas, myrmekite replacement occurs within the megacrysts, possibly suggesting late-stage magmatic crystallization. Most megacrysts are mantled by a thin grain-reduced selvedge and locally, in outcrop, a number of feldspars appear to be fragmented. Microperthites are common and a complex zoning resulting from variations in the concentration of exsolved plagioclase may reflect an original magmatic zonation (as suggested by others). Our initial study indicates that deformational effects dominate the textures in the Gray's School body, but that there are significant indications of an igneous protolith. Recent suggestions of a predominantly metasomatic origin for the K-feldspars in the Gray's School body have not been substantiated, although we do see evidence of some alteration, possibly by minor alkali metasomatism.

Yucca Mountain is currently the proposed site to store and house some of this nation’s nuclear waste. Uranium is a major component of nuclear waste, so the chemical environment around the aqueous uranium complexes is important to study. As such, the goal of my research is to understand the interactions of various aqueous uranium complexes. From radial distribution function (RDF) results of the complex [(UO2(H2O)5]2+ we found the distance between the uranium atom of uranyl and the oxygen atom of water to be at 2.4 Å to 2.5 Å. The structure of the non-solvating waters features an oxygen-oxygen distance of 2.8 Å, and an oxygen-hydrogen distance of 1.8 Å, and 3.2 Å. In the future we hope to expand this research and use molecular dynamics to continue to study these interactions on a nanosecond timescale.

This research focused on the positioning of the T- cell receptors (TCR) both before and after the binding of antibodies.  The first part of this was done by culturing Jurkat cells and using confocal microscopy to identify on the cell surfaces the placement of the TCR components both before and after antibody binding.  After the TCRs were found to aggregate together and be taken up within the cell, the rest of the project focused on the identification of the cell structures into which the TCR was taken up.  The second part of the study used thin-layer chromatography to determine the solubility of the TCR components both before and after antibody binding.

Glial Fibrillary Acidic Protein, or GFAP as it is most commonly referred to, is an intermediate filament in certain cells. Since it is an intermediate filament - meaning that it provides structure and support for the cell - it should not be found on the outsdie of the cell, only on the inside. What has been shown is that when Calvaria cells, the cells in a fetal mouse brain that eventually harden to become the skull of the head, are cultured from fetal mice, there is a "contaminant" cell that comes with it. This is a glial cell and it has been shown to have GFAP on the surface. (1, 2)  The goals of this research are to 1) successfully harvest and culture the glial cells on top of a feeder lawn of calvaria 2) find different monoclonal antibodies (McAbs) that will bind to different epitopes on GFAP, see if these mcAbs opsinize the glial neuronal cell for lysis by serum complement. Since the glial cells are in such low proportion to the calvaria cells there was great difficulty in seeding a sufficient number for proper analysis.  Therefore this research is still ongoing.

The topic of biodiversity has gained increasing interest in the last few decades, especially because of the negative effects humans pose on biodiversity through destructive actions like deforestation. This study examined the species distribution and diversity in  “El Amatal Forest Reserve” in western El Salvador near the Pacific Ocean. This type of transitional-tropical decidous forests has not been studied extensively and data on species richness and distribution is lacking. The data was collected from three randomly selected quadrats, each  in dimension and all individuals equal to or greater than 2.5 cm in diameter at breast height (DBH) were measured and identified. The data were compiled and statistically analyzed. The dominant species were identified and relationships between species were investigated by looking closely at the distribution of each species and distributions of combinations of two species to detect relationships between pairs of species. Results show lower species diversity than adjacent tropical forests, and that the palm species “huiscoyol” (Bactris major, Aracaceae) and “cordoncillo” (piper sp. Piperaceae) are the dominant species, with Bactris major showing an effect on the composition and diversity present in El Amatal. The most common species were looked at in more detail in an attempt to understand how and why they are distributed and if it is the result of biological factors (e.g. allelopathy), and what possibly causes specific species to repel or attract each other.

April 17, 2003
Created by: Peg Barkley
Mathematics, Computer Science
and Statistics Department