Abstracts from 2002 Joint Science
Symposia for Student Research






Abstracts from the Department of Biology

Comparison of aquatic drift fences with traditional funnel trapping as a quantitative method for sampling amphibians

Sarah Budischak, Ana Gabela, Sarah Hooper, Laurent Ropars, and John D. Willson

Recent reports of amphibian declines have raised concern for the future of amphibian populations world-wide.  Unfortunately, reports of many of these declines are based on unreliable data or casual observations.  As such, increased long-term quantitative sampling of amphibian populations and the development of new methods for such sampling will be required to accurately monitor amphibian populations and communities.  Although drift fences have been widely used as a quantitative method for sampling terrestrial amphibians, this technique has seldom been applied to aquatic environments.  We examined the efficiency of aquatic drift fencing used in combination with funnel traps relative to traditional aquatic funnel trapping of amphibians in a ephemeral wetland located in the western Piedmont of North Carolina.  We employed a paired design that used five blocks, with one array of each trapping method per block.  The drift fencing treatment captured significantly more amphibians (both larval and adult) and more species of amphibians than the traditional funnel trap arrays.  Our results suggest that aquatic drift fences used in combination with funnel traps will provide a better, yet still economical, method for sampling aquatic amphibians than funnel traps alone.  However, replication of our design over a wider diversity of habitats and for longer periods of time will be necessary to confirm this conclusion.

Identification of a candidate gene for no mitochondrial derivative (nmd) in Drosophila melanogaster

 Sean T. Burke1, Fitz Sturgill1, Nurit Wolf2, Margaret T. Fuller3, and Karen G. Hales1

1Department of Biology, Davidson College, Davidson, NC

2Department of Molecular, Cellular and Developmental Biology,

University of Colorado, Boulder, CO

3Departments of Genetics and Developmental Biology, Stanford University, Stanford CA

We have identified a candidate gene for no mitochondrial derivative (nmd), which is required for mitochondrial aggregation during spermatogenesis in the fruit fly Drosophila melanogaster. In wild type testes, mitochondria gather on the meiotic spindle, aggregate and fuse in post-meiotic spermatids, and elongate beside the flagellar axoneme, perhaps to permit efficient delivery of ATP. The nmd mutation was generated through insertional mutagenesis with the a P element. Homozygous mutant males are viable but sterile and show defective mitochondrial aggregation during meiosis and in post-meiotic spermatids. We used inverse PCR to obtain genomic DNA flanking the site of the P element insertion. The nmd P element is inserted in the 5' UTR of a previously uncharacterized predicted gene. The layout of the surrounding chromosomal landscape is such that the P element is unlikely to affect any other loci. Sequence analysis indicates that the product of the candidate nmd gene is a putative member of the AAA ATPase superfamily, with significant homology to a previously characterized yeast mitochondrial protein.  This work was supported by Davidson College.

The Effects of Mammalian Herbivory on Japanese Honeysuckle (Lonicera japonica) in a Mixed Pine-Hardwood Forest in Piedmont, North Carolina

Heather Carroll, Bradley Escaravage, Amanda Johnson, and Ramya Parthasarathy

Japanese honeysuckle is an invasive exotic vine that is widely distributed in eastern North America.  This exotic species has the capability to competitively exclude native species in the forests it inhabits.  Herbivory by white-tailed deer may provide some control over the growth of these Japanese honeysuckle populations.  However, intense browsing by large deer populations also can change forest composition .  This research evaluated the density and dispersion of Japanese honeysuckle in a mixed pine-hardwood forest in Piedmont, North Carolina, and evaluated the ability of mammals such as deer and rabbits to limit honeysuckle growth.  The experiment used a paired plot design, with one half of each plot enclosed by a poultry mesh fence and roof that excluded deer and rabbits.   The results indicate that the dispersion of Japanese honeysuckle in this forest does not deviate significantly from random.  We also found a significant effect of mammalian herbivory on Japanese honeysuckle, since in the majority of plots (11 of 13), we saw more growth of honeysuckle stems inside the exclosure than in the control subplot.  These results suggest that measures to reduce densities of deer in these forests could exacerbate problems associated with Japanese honeysuckle.

Correlates of Distribution of Poison Ivy (Rhus radicans) in a Mixed Pine-Hardwood Forest in Piedmont North Carolina

Susanne E. Francis and Patricia A. Peroni

Poison ivy (Rhus radicans) is a liana whose ecology remains largely unknown.  This study sought to determine if climbing poison ivy vines were non-randomly distributed with respect to tree size and species.  A 0.5 ha plot was surveyed in a mixed pine-hardwood forest in Davidson, NC.  Trees greater than 10 cm DBH were identified according to species, DBH, and the presence/absence of poison ivy vines.  A 1-m2 quadrat was used within each plot to estimate densities of non-climbing poison ivy stems.  Of the 261 trees censused, 12.3% bore poison ivy vines, and percent infestation varied significantly among species groupings.  Oaks (Quercus spp) showed the greatest percent infestation (20.25%), followed by pines (Pinus spp., 15.38%).  The rare pioneer and mature tree species groups demonstrated 2.33% and 6.76% infestation, respectively.  The presence of climbing poison ivy vines also varied significantly with diameter class.  The larger size classes experienced two to three times greater percentage of infestation than the smallest size class (10-20 cm DBH).  Within the oak species grouping, percent infestation with poison ivy increased significantly as diameter class increased, but size showed no significant influence on infestation rates for pines.  The dispersion of trees that bore poison ivy vines did not deviate significantly from random, but the non-climbing.

A Photographic Atlas of Xenopus laevis Embryogenesis

William Graham and Barbara Lom

The South African clawed frog Xenopus laevis is widely used as a model organism in developmental biology because its transformation from zygote to tadpole can be easily observed in the laboratory.  Since individual variation and temperature dramatically affect the developmental progression of ectotherms, Xenopus embryonic stages cannot be assigned chronologically.  In 1956 Nieuwkoop and Faber published an illustrated and extensively annotated anatomical staging table that became the standard atlas for uniformly and consistently identifying Xenopus stages.  In order to facilitate more accurate determination of Xenopus laevis embryonic stages, we have compiled a photographic atlas to accompany Nieuwkoop and Faber's illustrated staging table.  This photographic atlas is the first comprehensive collection of digital images of Xenopus embryos detailing dorsal, ventral, and lateral perspectives of embryos at nearly every stage of development (stages 1-50).  The photographs provide more representative depictions than do the original illustrations.  Additionally, we have annotated the photographs with the most indicative structural features described in Nieuwkoop and Faber's extensive text to assist in the identification of prominent anatomical features.  We anticipate that this web-based photographic atlas will improve students' and researchers' abilities to identify Xenopus laevis stages more easily and accurately.  The atlas will be available at: <www.bio.davidson.edu/people/balom/306/xen/xenhome.html>.

Long-term Monitoring of Semi-aquatic Turtles in the Western Piedmont of North Carolina

Kristine L. Grayson and Michael E. Dorcas

Since 1999, the Davidson College Herpetology Laboratory has consistently monitored semi-aquatic turtle populations at a local farm pond just east of the school.  During this time, three species of turtle have been consistently captured at this site using turtle hoop traps baited with sardines.  Turtles captured include eastern mud turtles (Kinosternon subrubrum), eastern painted turtles (Chrysemys picta), and snapping turtles (Chelydra serpentina).  Captured turtles are marked, measured, weighed, and released.  Data spanning several years now allows us to draw several conclusions about capture frequencies and growth rates.  The majority of individuals captured are painted turtles, among which we have found substantial variation in recapture rates. We have documented significant variation, not only size, but general morphology between male and female painted turtles.  Additionally, recapture rates for this species indicate that the majority of the population has been marked and that over 90% of a painted turtle population within a farm pond can be marked within a 2-3 month trapping period.  Long-term continuation of this study will allow detailed investigations of factors affecting the characteristics of turtles at individual and population levels.  We are currently measuring overwintering temperatures of free-ranging painted turtles using microdataloggers attached to the turtles’ carapaces in order to further understand their thermal ecology.

The effect of gibberellic acid on seed dormancy in white campion (Silene latifolia)

John Kogoy, Meg LaFontaine, Ashley Price, and Monica Siegenthaler

White campion (Silene latifolia) is a dioecious perennial that has been used as a model system for investigations into the dynamics of fragmented plant populations for the past decade.  Many white campion seeds can remain viable and dormant in the field for over four years.  Although dormancy is a principal seed survival mechanism in nature, persistent dormancy can hinder laboratory investigations.  To determine if application of gibberellic acid provides a potential technology for breaking seed dormancy in white campion, we exposed  groups of seeds to different concentrations of GA3 (a form of gibberellic acid):  high (2.6X 10-3 M), medium (2.6 X 10-4 M), low (2.6 X 10-5 M), and a control (deionized water).  We measured germination in growth chambers over a 2 wk period and calculated the mean fraction of seeds germinated for each treatment (n= 5 replicates per treatment, with 100 seeds/replicate).  At d 14, the mean cumulative fraction germination  of the high and medium GA3 treatments were significantly greater than the mean for the control.   The results of this study indicate that GA3  can be used to effectively break dormancy in white campion seeds at concentrations between 2.6 X 10-4 M and 2.6X 10-3 M, with the highest concentration tested yielding the greatest germination response.  Future studies will investigate if concentrations of GA3  greater than 2.6X 10-3 M further improve white campion germination.

Ethanol does not affect optic nerve development in Xenopus laevis embryos

Peter Leese and Barbara Lom

Fetal alcohol syndrome (FAS) is a collection of birth defects that occurs in some children born to mothers who consumed alcohol during pregnancy.  FAS children often exhibit mental retardation and neurological deficits such as vision acuity deficits due to optic nerve hypoplasia.  In order to evaluate ethanol’s influence on optic nerve development we examined the targeting of retinal ganglion cell (RGC) axons in developing Xenopus laevis tadpoles exposed to ethanol.  RGC axons were labeled by anterograde transport of horseradish peroxidase, allowing visualization of the entire optic tract between the retina and tectum.  The gross morphology of optic tracts in tadpoles exposed to ethanol did not differ significantly from controls.  These results suggest that ethanol does not disrupt RGC axon pathfinding or target recognition.

Assessing filtration of two oysters (Crassostrea ariakensis and C. virginica) in short-term feeding trials at varying algal densities

David C. Love and Christopher J. Paradise

Oysters, which are filter feeders, provide important ecosystem services by filtering suspended particles, algae, and pollutants from coastal marine waters. Because of the eastern oyster’s decline, caused by disease, overharvesting and habitat destruction, scientists are researching alternative species of oysters for introduction in Chesapeake Bay.  Our study gathered preliminary data on feeding of the Suminoe oyster (Crassostrea ariakensis) in comparison to the eastern oyster (C. virginica).  We tested the two oyster species’ feeding rates in response to varying algal densities, in short term trials in the laboratory.  We hypothesized that Suminoe oysters would filter water at a higher rate, due to a higher growth rate.  In actuality, we found that both species cleared algae at similar rates at all algal densities, except the very highest algal density we tested.  These preliminary results indicate the Suminoe oyster to be comparable to the eastern oyster at filtering algae at most densities likely to be found in natural conditions.  Higher growth rates by the Suminoe oyster may be caused by higher efficiencies of converting algal biomass to oyster biomass, which may ultimately allow higher overall algal filtration if introduced into the Bay.  However, other factors must also be investigated to determine the utility and feasibility of a non-native introduction into any ecosystem.

Preparation of Saccharomyces cerevisiae Genes for DNA Microarray Use

Peter Lowry and A. Malcolm Campbell

The recent exponential increase in genomic research brought about the problem of how to produce genomic data cheaply and efficiently.  DNA microarrays are now used to analyze genome-wide changes, and are a cheap, efficient, high-throughput method of genomic testing.  However, the accuracy and effective range of DNA microarrays are not known.  This study will have two main objectives:  to work out protocols such that future genomic studies may easily be done on the Davidson campus, and to examine the accuracy and effective range of DNA microarrays with respect to more traditional methods, such as electrophoresis gels.  Eleven genes were chosen from the Saccharomyces cerevisiae genome on the basis of the criteria that they: had no sequence similarity to the rest of the yeast genome, had an internal restriction site, and were at least 500 base pairs in length.  A 500 base pair segment of each gene was then amplified with PCR, transformed into a plasmid vector, and verified with electrophoresis gels.  Future studies will be done to allow microarray analysis of these cloned genes.

Optimizing Hybridization Conditions of DNA Microarrays

Jennifer Madden and A. Malcolm Campbell

DNA microarrays are very popular in genomic studies and should be integrated into the classroom.  In order to accomplish this task, a simple consistent procedure needs to be developed for undergraduate use.  SYBR Green I and II along with a range of blocking conditions, probe concentrations, and temperatures were evaluated.  Yeast DNA microarrays were hybridized with yeast genomic DNA labeled with either Alexa Fluor 546 or Alexa Fluor 647.  All spots on the microarray should have been yellow when processed and scanned since both probes should have hybridized equally.  However, all spots were not labeled and those that did label were primarily red or green.  Probes with DNA larger than 1000 bp tends to aggregate rather than hybridizing to the spot.  Perhaps this phenomenon contributed to the lack of labeled yeast genes on the DNA microarray.

The Visual Art of HIV/AIDS: An Interdisciplinary Approach to Teaching about HIV/AIDS

Anna G. McDonald and David R. Wessner

Undergraduate education is shifting from fragmented subject areas to unified disciplines.  To add to this growing interdisciplinary awareness, we are suggesting an approach to teaching the biology of HIV/AIDS by using the visual art that surrounds this epidemic. Our reasons for formulating an alternative biology curriculum are:  (1) to address different learning styles, thereby increasing the students’ understanding of the material, and (2) to affirm the interconnections between biology with art to hopefully stimulate creativity among students.  We detail how pieces of art can be used to initiate discussions about biological/medical consequences of HIV/AIDS, history of the epidemic in the US, and the emotional ramifications of the disease.  By describing the integrative curriculum, we discount the fabricated intellectual boxes in which academia traditionally resides.

The effects of phenol and SDS on ethanol resistant mutants of reovirus T3D 

Elizabeth K. Nugent and David R. Wessner

Previously a cohort of 7 unique type 3 Dearing reovirus mutants were isolated for their increased resistance to ethanol. All 7 viruses contained mutations in the M2 gene segment that resulted in predicted amino acid changes between 425 and 459 of the μ1 protein. This unique set of viruses was further shown to be more resistant to heat (55°C, 30 minutes) than T3D. Because heat and ethanol resistance was attributed to these mutants, we hypothesized that the viruses were general stability mutants exhibiting increased stability in the presence of various chemical and physical agents. To test this hypothesis, we examined both phenol and SDS resistance on a representative sample of the viral cohort. When the ethanol resistant viruses and T3D were exposed to 1% and 1.5% phenol for 15 minutes at 37°C, isolates 3a9 and 3d5 showed a significantly smaller decrease in infectivity in comparison to T3D and isolate 3b4 showed a small mean loss of infectivity and high variability, causing the results to lack significance. When ethanol resistant viruses and T3D were exposed to 1.0% and 1.5% SDS, the mean infectivity decrease across ethanol resistant isolates 3d5 and 3b4 was significantly less than that of T3D and a trend of increased resistance was demonstrated in isolate 3a9. The M2 mutant viruses exhibited increased resistance to ethanol, heat, phenol, and SDS, leading us to classify them as general stability mutants. We hypothesize that the M2 mutations increase the strength of the μ1:σ3 or μ1: μ1 outer capsid protein interactions and the protein alterations are the basis for resistance to various chemical and physical agents in this cohort of unique viruses.

Xenopus retinal neuron dendrite initiation is not dependent on basic fibroblast growth factor

Ramya Parthasarathy, Drew Weber, Nate Leachman, and Barbara Lom

Basic fibroblast growth factor (bFGF) influences retinal ganglion cell (RGC) proliferation, survival, and axon guidance in the developing Xenopus laevis tadpole.  Both bFGF and FGF receptors are expressed in the developing retina during stages when retinal ganglion cells (RGCs) elaborate dendritic arbors and synapse with other retinal neurons.  Previous studies in our lab indicated that exogenous FGF-2 applied to the retina between stages 38 and 45 enhances RGC dendritic branching without affecting primary dendritic outgrowth.  Because primary dendrites are likely initiated before stage 38, we investigated how FGF-2 applied at stage 34 influenced RGC dendritic arborization.  Control, EGF, or bFGF-treated green fluorescent beads were microinjected into retina at stage 34.  RGCs were then labeled by microinjecting rhodamine dextran into the tectum, where RGC axons terminate.  Retrograde transport of the fluorescent dextran delineated RGC dendritic arbors.  Analyzing the morphology of RGC dendritic arbors revealed that primary dendrite outgrowth from the soma was unaffected by bFGF or EGF.  RGC dendritic branching was unaffected by early exposure to bFGF, yet later exposure to bFGF significantly enhanced.  Thus bFGF specifically affects RGC dendritic branching without influencing primary dendrite initiation.

Investigation of mitochondrial morphogenesis in Drosophila melanogaster: Recombination mapping of two new mutants with defects in nebenkern formation

Laura Quillian, Marisa Wilson, and Karen Hales

We are mapping by recombination the position of mutated genes in Drosophila melanogaster.  We have used fly stocks that show recessive defects in mitochondrial fusion of the nebenkern and in the elongation of mitochondria during spermatogenesis. Strain 60-208 contains a mutation that affects the nebenkern (during onion stage) of spermatid formation.  Strain 57-093 also shows lumpy nebenkern formation and defects in elongation. These strains were originally isolated in a screen by Dan Lindsley (UCSD) and Barbara Wakimoto (Univ. of Washington). The study of mitochondrial morphogenesis during spermatogenesis in the testes of Drosophila melanogaster offers insight into a vast array of undiscovered genes.  Genes thus discovered include fzo (fuzzy onions gene, which encodes a GTPase that regulates the fusion of mitochondria during spermatid formation [Hales and Fuller, 1997, Cell 91: 121-129] ) and nmd (no mitochondrial derivative gene which is required for mitochondrial aggregation in spermatids; see Sean Burke’s poster).  Close study of wild-type mitochondrial formation in normal spermatogenesis preceded experimentation. Recombination mapping was performed using versions of the second or third chromosome carrying multiple recessive markers. Dissections of testes from flies homozygous for each recombined chromosome were performed and analyzed to determine where each mutation lies on the chromosome. The locations on the second chromosome for two different genetic mutations have been uncovered.  In 60-208 the location of the mutation lies near the recessive marker dumpy (dp) on chromosome two.  In flies from stock number 57-093, the mutation was mapped near to recessive marker black (b) on chromosome two.  This work was supported by Davidson College.

An Investigation of Current Ethical Issues in Scientific Research

Catherine Rainbow and Karen Bernd

The fast pace of scientific research has significantly advanced our ability to manipulate people’s lives through medical technology such as genetic engineering.  Since this scientific research is being produced so rapidly, it is paramount that we maintain standard ethical research practices and boundaries in order to protect research subjects as well as those who will benefit from the technology in the future.  Science, which builds upon past research, should be composed of honestly collected data and results so that future researchers desiring to build upon past research results will have a solid and accurate base from which to begin new experimentation.  Therefore, we must ensure the integrity of research practices and discuss the purposes of technological advances so that we will be able to understand their immediate and future consequences.  In order to investigate the controversial issues of scientific research, a study was done concerning the application of a variety of ethical principles and theories.  These principles, such as beneficence and autonomy, and theories, such as deontology and utilitarianism, were individually studied and compared through discussions and papers. Once the ethical principles and theories were understood, they were applied to specific case studies of scientific research misconduct, as well as to ethical issues in the scientific world such as animal testing, research on human subjects, informed consent, cloning, etc.  Throughout the investigation, a combination of discussions and papers were used to thoroughly cover each of the previously stated topics.  As a final project, the papers were compiled into a web page focused on an undergraduate study experience of scientific research ethics located at the following address: http://www.bio.davidson.edu/people/kabernd/indep/carainbow/ethics.htm

Effects of land use and disturbance on insect communities in headwater streams north of Charlotte, North Carolina

Aaron Spivak, Maury Gage, and Christopher Paradise

Increased development north of Charlotte, North Carolina, threatens habitat quality for aquatic life in streams by decreasing riparian buffers near streams and increasing the amount of runoff into streams.  Sedimentation from erosion and poor construction practices is a principal source of stream pollution in developing areas.  Our research focused on the relationship between benthic insects and stream condition as affected by surrounding land use and in-stream disturbances.  Because different insect families can tolerate varying levels of pollution, we were able to use the insects as indicators of stream health.  We visited nine streams periodically from May to November 2001, collected insect samples, conducted water chemistry tests, and assessed the physical habitat of the stream and its immediate surroundings.  We used a Geographic Information System (GIS), aerial photographs, and digitized topographic maps to determine watershed boundaries and land use patterns within each watershed.  The watersheds were categorized as low, irregular, or high disturbance, based on land use and chemical and physical variables of the stream.  Insect communities were consistently more diverse and abundant in streams draining low disturbance watersheds than in streams draining watersheds with irregular or high disturbance.  Of all samples taken at high disturbance streams, no stoneflies or mayflies were found.  Stoneflies have a low tolerance to pollution, and they were found regularly in streams with low disturbance watersheds.  These results imply a decrease in aquatic habitat quality in human-impacted watersheds and also suggest a need to protect those streams yet unaffected by development by imposing stricter riparian buffer regulations and erosion control practices.

The Effects of Habitat Disturbance on Stream Salamanders: Implications for Buffer Zones and Watershed Management

John D. Willson and Michael E. Dorcas

In light of recent amphibian declines it is necessary to evaluate the effectiveness of conservation efforts aimed at these species.  In many areas, small streams support large populations of amphibians, particularly salamanders, and are often the first habitats to be affected by human development and pollution.  Development within stream watersheds is often regulated through buffer zone regulations.  Although buffer zones are designed to protect ecosystems and water quality within watersheds, research is necessary to determine if buffer zones are adequate to conserve populations of amphibians inhabiting small streams.  We examine the effectiveness of the current buffer zone system of small watershed management in conserving populations of stream-dwelling salamanders in ten small streams (draining <100 acres) in the western Piedmont of North Carolina.  We captured salamanders using funnel traps and systematic dipnetting and used a Geographic Information System (GIS) to calculate the percentage of disturbed habitat within the watershed of each stream and within 35, 100, and 200-foot buffer zones around each stream upstream of sampling locations.  While relative abundances of salamanders were found to be strongly inversely proportional to the percentage of disturbed habitat in the entire watershed (R2 = 0.70 and 0.58), we found little to no correlation between relative abundances of salamanders and the amount of disturbed habitat present within delineated buffer zones (R2 values between 0.01 and 0.40).  Thus, if they are to be effective at protecting stream-dwelling salamanders, conservation efforts aimed at preserving the biodiversity of headwater streams must consider land use changes throughout the entire watershed, rather than just preserving small riparian buffer zones.

A Novel Fluorescent Technique to Visualize Kidney Organogenesis in Xenopus Tadpoles

Robert Zsoldos, Sarah Hooper, and Barbara Lom

The vertebrate kidney is a highly complex organ, consisting of filtration ducts termed nephrons.  Kidney development progresses through three major stages, the pronephros, the mesonephros and the metanephros.  The pronephros, a single nonintegrated nephron comprises the functional kidney in Xenopus laevis.  Previous studies have identified and visualized pronephric tubules in fixed tadpoles using monoclonal antibodies, a process that is expensive and limited to late stages of development.  We have developed a novel fluorescent in vivo visualization technique that overcomes these technical disadvantages and allowed us to investigate the role of retinoic acid (RA), a vitamin A derivative, in kidney morphogenesis.  RA is known to play a crucial role in specifying the Xenopus anterior-posterior axis.  Stage 12.5 tadpoles were exposed to bath applications of 10 -7 and 10 -6 M RA.  They were reared to stage 43 and injected with the rhodamine dextran.  Kidney filtration caused this large fluorescent dextran to be concentrated in the kidney walls, delineating tubules.  Kidney tubule morphology of living tadpoles was observed by fluorescent microscopy.  The lengths, widths, and tubule areas of control and RA-treated kidneys were measured.  In addition, tubule circumference and diameter were determined in cross-sectioned tissues.  Tadpoles exposed to retinoic acid exhibited larger kidney areas, lengths, widths, tubule circumferences, and tubule diameters than did vehicle-treated controls.  RA exposed tubules were visibly larger and less coiled than controls.  Thus, RA disrupts the normal patterning of vertebrate kidney organogenesis.

Abstracts from the Department of Chemistry

The Synthesis of Heterocyclic Molecules Using Diaziridines and Diazirines

Jamie Causey

In this study, the synthesis of 3,3-pentamethyldiazirine from cyclohexanone was attempted with different starting materials.  The synthesis involves adding hydroxyl-amine-O-sulfonic acid to the starting material in ammonia to form the diaziridine, then oxidizing this product using silver oxide to form the diazirine.  If a double bond is present near the diazirine group, the product will spontaneously rearrange to form the desired heterocylic molecule.  After attempting a variety of starting materials, the diaziridine of 2-acetylfuran was synthesized, and attempts were made to synthesize its diazirine.

Analysis of Multi-component systems with Principle Component Analysis: A Technique for the Undergraduate Lab

Natalie Clayton

This project was designed to introduce a statistical method (principal component analysis) to the undergraduate chemistry laboratory program.  Three types of systems were investigated by UV-Vis spectroscopy.  The simplest system involved a Beer's Law study of solutions containing methyl orange and a contaminant dye.  PCA was employed to resolve the spectrum of methyl orange from that of the contaminant.  The acid dissociation equilibrium of methyl orange was also examined by recording spectra for the dye in solutions of varying pH.  The spectra of the acid and base forms of the dye were determined as well as the acid dissociation constant.  The complexation of cobalt(II) ion by ethylenediamine was also studied.  PCA was applied to determine the number of complex species.  These systems and the statistical analysis of each are given in detail in order that professors may integrate these statistical skills into undergraduate laboratory programs. 

Separation of Ruthenium and Iron Complexes using High-Performance Liquid Chromotography

Ashley Crimmins

In this study, the separation of tris-2,2'-bipyridineiron(II) hexafluorophosphate, tris-2,2'-bipyridine-ruthenium(II) hexafluorophosphate, and bis(tri-2-pyridylamine)ruthenium(II) hexafluorophosphate was attempted using high-performance liquid chromatography (HPLC).  An octadecylsilane column was used, and an isocratic mixture of aqueous trifluoroacetic acid and acetonitrile were used to elute the complexes.  The effects of varying the concentration of the trifluoroacetic acid and the fraction of acetonitrile were explored.

Ab Initio Computations for Ground State and Excited State zinc(II) substituted 1,10-phenanthroline and substituted benzenethiol ligands

Alan Cubre

Ab initio computations for a series of bis(benzenethiolato)(2,9-dimethyl-1,10-phenanthroline)zinc(II) complexes indicate that a ligand-to-ligand charge transfer (LLCT) results when an electron is excited from a sulfur-p-thiol molecular orbital (HOMO) to the p-p* molecular orbital on the phenanthroline (LUMO).  The energies for HOMO and LUMO molecular orbitals for each zinc compound as well as the electronic energy for the entire complex were determined.  Restricted CIS computations using a 3-21g* basis set produced excitation energies and the corresponding wavelengths for the HOMO to LUMO transitions.  Comparison of experimental excitation energies to theoretical models suggests how altering the substituents on the benzenethiol affects LLCT.  Bond angles and bond lengths from geometry optimizations employing restricted Hartree Fock Theory and a 3-21g* basis set are compared to reported crystallographic data.  The optimized geometries also yielded charge separation between the phenanthroline nitrogens, zinc(II) and sulfur.  Frequency calculations provided values for DG and DH associated with conformational changes for each geometric isomer.

Determination of Thiamine Concentration in Beer

Charles Lea

The goals of this project were to determine the concentration of a single vitamin, thiamine (Vitamin B1), in a variety of beers and to determine if there is a correlation of thiamine concentration with the darkness of the beer as well as with the region, i.e. European vs. American Beers.  Two analytical methods were examined for determination of thiamine.  The first method consisted of the colormetric determination of thiamine using the reagent 4,4’-dimethoxydiquinone (DMDQ).  DMDQ proved difficult to synthesize and purify, and the relatively high absorbance of beer at key wavelengths would have made obtaining reliable quantitative data difficult.  The second method involved the determination of thiamine by reversed-phase high-performance liquid chromatography (HPLC).

Synthesis of a Water-Soluble Calix[6]arene Carboxylate Salt and Study of its Inclusion Properties with Bromonaphthalene Derviatives

Isaac Miller

Calixarenes are basket-shaped molecules formed by the coupling of phenol into a ring by methylene bridges at the ortho- position.  The hydrophobic core of these baskets can host other molecules, including neutral molecules, leading to interesting and useful inclusion compounds.  In this experiment, a water-soluble calixarene derivative was synthesized by the addition of carboxylic acid groups to each of the phenolic head groups.  This was achieved by an ether synthesis using sodium hydride and ethylbromoacetate, forming ethyl ester head groups, followed by basic hydrolysis with potassium hydroxide.  Two starting calixarenes were used:  calix[6]arene and p-tert-butylcalix[6]arene.  The p-tert-butylcalix[6]arene leads to a carboxylate derivative that is only slightly soluble in water, while the calix[6]arene carboxylate is completely soluble in water.  An

aqueous solution of the potassium calix[6]arene carboxylate salt was tested to determine its ability to complex bromonaphthalene derivatives known to phosphoresce in the absence of oxygen quencher.  In aqueous solution, the bromonaphthalene derivatives will phosphoresce only if complexed within a protective molecule such as the synthesized calixarene carboxylate salts.

Development of A New Undergraduate Organic Chemical Laboratory Experiment:Modification of the Diels-Alder Cycloaddition

Leah Uhernik

An existing Chemistry 202 organic chemistry laboratory experiment illustrates the Diels-Alder reaction shown in scheme 1: 

Scheme 1.  Cycloaddition of cyclopentadiene and 1,4 naphthoquinone.

This experiment works well, and produces a high yield of product.  In theory, the reaction should produce both the endo and exo product.  However, it produces only the more stable endo product.  Thus, the students are not seeing both possible Diels-Alder results.

A possible solution to this limitation is currently being researched.  Placing a substituent with a pi system, such as a cyano group, onto the 1,4-napthoquinone will hopefully provided competition among the carbonyl groups and produce both the endo and exo products.  The proposed reaction is shown in scheme 2.  This reaction is being studied by TLC, GC, NMR and GC-MS.

Scheme 2.  Diels-Alder cycloaddition of 2-cyano-1,4-naphthoquinone and cyclopentadiene

Using QSAR to Model the Relationship Between A-values and Biological Activity of Antihistamines

Cathy Williford

QSAR was used to determine the relationship between the biological activity of antihistamines and A-values.  An A-value is a steric parameter that represents the free energy difference between a substituent in an axial and in an equatorial position on a cyclohexane ring.  It was found that A-values, whether or not they were derived experimentally or by molecular modeling, did not demonstrate a high correlation to biological activity.  This leads to the hypothesis that the activity of antihistamines cannot be predicted solely by the steric properties of a substituent.  Other parameters, such as partition parameters, or solvent effects must also be involved in determining the biological activity of antihistamines.

Study of Electronic Transitions of Zinc (II) Complexes using UV-Visible Spectroscopy, Emissions, and Lifetime Analysis

Georgia Yowell

The objective of this research is to examine the excited states of Zn(II)(dithiol)- (phenanthroline) complexes in order to determine the type of electronic transitions and the expected excited state lifetime.  A synthesis of one complex, Zn(II)(benzenethiol)2 (5,6-dimethyl-1,10-phenanthroline) was completed.  UV-Vis spectra of five different complexes in three different solvents were measured.  Emissions and lifetime analysis were performed on the five complexes, and from this data the type of transition and excited state lifetimes were determined.

Abstracts from the Department of Physics

3D Simulation and Experiments of Rigid Body Motion

Adam Abele

We have created a new Java code-library for rendering 3D graphical representations of physical systems. The usability of this library was tested by designing and programming a 3D surface plotter, a molecular dynamics simulation, and a rigid body motion simulator.  The dynamics of a 3D spinning top in gravitational and magnetic fields were measured and compared to the rigid body simulation.

A Study of Dirac Delta Function Potentials in Quantum Mechanics

J. Meghan Carroll

P.A.M. Dirac, one of the founders of modern quantum mechanics, invented the Dirac delta function while studying the scattering of quantum mechanical particles.  As undergraduate physics majors, we were first introduced to the Dirac delta function as a way to mathematically describe the peculiar properties of the divergence of .  Subsequently, we have used the delta function to describe the charge density of a point charge in electromagnetism and the transition from position space to momentum space in quantum mechanics.  In this study we replace the finite square wells of canonical quantum mechanics problems with the Dirac delta function and analyze the new systems’ energy spectrum.  Specifically, we are exploring the bound and scattering states of the attractive and repulsive delta function potentials, and exploring the effect of delta function perturbations on existing potentials.

Numerical Solutions of the Time Dependant Schrödinger Equation in One- and Two-Dimensions

J. Meghan Carroll

While the one dimensional time dependent Schrödinger equation (TDSE) was modeled in the 1967 by Goldberg, Schey, and Schwartz on the Livermore IBM-7094, recent improvements in technology and the development of new computational algorithms support a more accessible model for quantum mechanical studies.  Three published TDSE algorithms (the Crank Nicholson, the Visscher, and the Operator Splitting) are solved and compared for accuracy and efficiency in one dimension. The fastest and most accurate algorithm is then extended into two dimensions and tested on model systems.

Fabry Perot Interferometry

Casey Chiang

The wave properties of two light sources are investigated using a Fabry Perot Interferometer.  This instrument uses two partially silvered mirrors oriented parallel to each other so that a light beam normally incident upon one of the mirrors encounters multiple reflections between the two mirrors.  Depending upon the distance between the mirrors, the overlapping light waves constructively or destructively interfere.  The transmitted beam is monitored as the distance between the mirrors is scanned and an interference pattern is observed.  In this experiment, interference patterns are obtained for a monochromatic HeNe laser and a multimode diode laser.  The measured patterns are compared with theoretical expectations for monochromatic and multimode sources of light.

Simulations and Experiments in Chaotic Dynamics.

Cheryl Greene

Chaos exists in the everyday life around us.  It is present in simple systems such as the damped, driven pendulum, the double pendulum, and the gravitational wedge.  These systems have been simulated using Java programs in order to demonstrate their properties.  Chaos was then observed experimentally using a simple pendulum and in more complicated inductor and diode circuits.  The period-doubling route to chaos was observed in both the experiment and simulation and Poincare sections were measured.

Analysis of Fourier Series Algorithms

Nick Hansell

            In the 1800’s, Joseph Fourier showed that any function can be written as a combination of sinusoidal functions.  When a function is written as a series of sine and cosine functions, if often reveals much useful information that would be hard to extract from the original function.  This process is known as Fourier analysis and is used in many fields today.  Finding the sinusoidal components of a function can be tedious and time consuming, so computer analysis is often necessary.  This study compares various algorithms to perform these calculations.

Maze Analysis

Anders Langworthy

Mankind has made and solved mazes by hand for thousands of years, but with the advent of computers it has become possible to analyze mazes and their solutions in much detail.  There are a great number of different algorithms used to solve mazes, ranging from a purely random walk to an intelligent path following system.  A detailed comparison of these algorithms in terms of solution speed and relative intelligence in solving different sized mazes will be presented.

Modeling the Spread of Disease

Travis Lloyd

A model of the spread of an infectious disease among a population of N individuals has been developed using a “random walk” model.  The model begins with a user-input number of infected individuals and susceptibility (the probability that an individual becomes infected), one can animate the motion of those infected and witness a general case of the spread of disease. After a period of time the members of the infected population are no longer infected. Rather, they have either died, been isolated for treatment, or have recovered and are now immune. In the commonly used SIR model of epidemic, the removed or R population represent these individuals. Thus, in the random walk model, after a certain amount of time elapses, the individual is no longer subject to the same conditions (s)he once was. The program shows these various susceptibilities by a change in color in a computer visualization of the population’s time evolution.

Resonance and the Orbits of Asteroids

Michael Malenbaum

There are certain distances from the sun in the asteroid belt at which no asteroids are found.  These distances are called Kirkwood gaps.  Asteroids that would be found with radii of these distances would be in resonance with Jupiter.  All asteroids are affected by the gravitational pull of the sun as well as by Jupiter.  However, an asteroid in resonance with a planet is systematically perturbed and will eventually escape  One Kirkwood gap is located at approximately 2.5 astronomical units from the sun.  This gap is called the 3/1 gap because an asteroid with this orbital radius completes three revolutions in the time it takes Jupiter to complete one.  This study examines the stability of orbits within this gap by examining the lifetime of these orbits.

Spectroscopic Studies of Raman Scattering in Rubidium

Sharon E. Meidt

Raman scattering occurs when a photon of energy E1 excites an atom to a "virtual state" and then relaxes to an eigenstate E3, releasing a photon of energy E2 = E1 –E3. This process appears as a set of lines in the spectrum of light scattered by an illuminated sample. The lines arise as a result of inelastic scattering of the photons with atomic or molecular vibrations or rotations in the scattering material. The frequency difference between the incident photon and the scattered photon is the energy separation between eigenstates E2 and E3.  This process was studied in a Rubidium sample excited with incident light from a Ti:Sapphire laser.  The sample was heated to several hundred Kelvin in both a heat pipe and an oven constructed for the experiment.  The resulting spectra were analyzed and examined for characteristics of Raman scattering and the eigenstate energy levels were identified.

Chladni Plates

Gray Patterson

Standing waves are investigated on circular, square, and rectangular surfaces by sprinkling sand on the surface and tuning the driving frequency until well-defined patterns emerged.  The sand would settle on the nodal lines, or lines of no vibration, revealing some very complicated standing wave patterns.  The measured resonant frequencies depended on the surface tension and mass density of the membrane.  When the surface is clamped on all sides, the boundary conditions for the two dimensional differential equation are known and the system is modeled numerically.  In this case, I show that the standing wave patterns coincide with solutions to Schrödinger equation for a similarly shaped two dimensional infinite quantum well.

Rubidium: Hyperfine Structure and associated Broadening Mechanisms

Diana Pendergrast

Electrons in atoms have certain allowed energy states.  The solution to the Schrödinger equation for the hydrogen atom revealed that these states can be represented by specific quantum numbers.  Simple combinations of these quantum numbers reveal the electronic structure of an atom.  Further electronic structure, namely hyperfine, is caused by the coupling of the electron's spin with the nuclear spin. Transitions between different electronic energy states occur when energy is absorbed or emitted in the form of a photon.  In this experiment, the hyperfine structure of Rb85 and Rb87 isotopes was examined using a tunable diode laser and photodetector.  To eliminate the effects of Doppler broadening, a saturated absorption technique was employed.  Two broadening mechanisms were also explored as a function of temperature:  Doppler broadening (caused by the varying velocities of the rubidium atoms) and pressure broadening (caused by the collisions between atoms).

Photoluminescence Excitation Spectroscopy of Semiconductor Quantum Wells

Patten Priestley

Photoluminescence excitation spectroscopy is used to investigate excited states in GaAs/AlGaAs quantum wells.  Since the excited state energies are much larger than the average thermal energy, these levels are generally not populated and photoluminescence from these states is not observed.  In order to detect the excited states, laser excitation is tuned over a range of energies while monitoring the light emitted from the ground state.  When the energy of the exciting laser coincides with the energy of an allowed state, absorption is enhanced.  Electrons that are excited to this state relax to the ground state by releasing phonons (packets of heat) and then fall from this level by emitting a ground state energy photon.  A peak is observed in the detection signal as the laser is scanned through the excited state.  Using this technique, I determined the excited energy levels in the quantum wells over a range of temperatures and compared them with theoretical predictions.

Quasi-molecular  Simulation of Water Droplets

Chris Schamper

            Quasi-molecular modeling simulates a macro-system by treating groups of molecules as single particles.  We test the validity of this approach by simulating a water droplet consisting of 500 quasi-molecules. The first simulation shows a water droplet forming and then falling off of a ceiling using only interactions between the quasi-molecules. Another simulation modeled the collision of two water droplets of comparable size. The last simulation provided a picture of a water droplet interacting with the pool of water and the resulting compression-wave within the liquid.

Computer Modeling of Diffraction Patterns and Holograms

Andrew R. Schoewe

Franhauffer and Fresnel diffraction patterns were created by illuminating various apertures with a laser.  These patterns were then analyzed using image analysis software and compared to a computer simulation based on Feynman Path Integrals.  Franhauffer diffraction (the limit of Fresnel diffraction at large distances) was explored by reconstructing the image of a computer-generated hologram.

A Study of Chaotic Dynamics in an Array of Spinning Magnets

Lee Wheless

An array of interacting magnets is a simple but important model for the study of ferrous materials.  We have modeled this system classically using an array of magnets with the assumption that the torque about one magnet is due to nearest neighbor interactions is:

t = m^2(1 + c)*1043*(B/T) sin q.

This system is shown to exhibit periodic and chaotic behavior depending on the initial temperature and field strength.

Abstracts from the Department of Psychology

The Effects of Flunitrazepam and Oxycodone on Motor Performance

Paul Bryant

The purpose of the present study was to examine the interactions between flunitrazepam and oxycodone on motor performance.  Using latency to fall from a rotorod apparatus to measure motor performance, 9 rats were cumulatively injected with three increasing doses of flunitrazepam (0.1, 0.56, and 1.7 mg/kg) during each of four individual sessions.  Rats were pretreated with saline, 1.0 mg/kg oxycodone, 3.0 mg/kg oxycodone, and 1.0 mg/kg oxycodone + 1.0 mg/kg naltrexone in sessions 1, 2, 3, and 4, respectively.  Flunitrazepam produced dose-dependent decreases in motor performance, and these effects were attenuated by pretreatment with oxycodone.  Naltrexone blocked the effects of oxycodone pretreatment, suggesting that the ability of oxycodone to attenuate the effects of flunitrazepam is due to its activity at the mu receptor.

The Potentiating Effects of (-)-Pentazocine on Cocaine-Induced Locomotion

Paul Bryant

High efficacy opioids have been shown to increase sensitivity to cocaine-induced locomotion, but little is known about the effects of cocaine in combination with lower efficacy opioids.  The purpose of the present study was to examine the effects of the intermediate efficacy opioid (-)-pentazocine on cocaine-induced locomotion.  Using an open-field chamber to measure locomotor activity, 9 rats were cumulatively injected with three increasing doses of cocaine (3, 10, and 30 mg/kg) during each of three individual sessions.  Rats were pretreated with saline, 1.0 mg/kg (-)-pentazocine, and 3.0 mg/kg (-)-pentazocine in sessions 1, 2, and 3, respectively.  Cocaine dose-dependently increased locomotor activity, while pretreatment with (-)-pentazocine was shown to further enhance this effect.  These results suggest that opioids of intermediate efficacy potentiate the locomotor-activating effects of cocaine.

Memory for Scenes: What Does Motion Add?

John E. Conway and Margaret P. Munger

Two experiments investigated boundary extension (BE), a memory distortion for still scenes that mimics taking a step back, and representational momentum (RM), a memory distortion for a moving object's position along the path of motion.  Two distinct patterns emerged: some participants exhibited BE in the still scenes and less BE when shown an approach, in keeping with RM; however, no BE was observed for other participants on the stills, yet the approach led to BE, opposite of RM.  Results suggest that BE occurs before RM.  Observers who initially construct a larger representation of a scene will include additional motion information, but observers who do not spontaneously expand the scene first use additional information (e.g. an approach) to construct this expansion.

Investigation of Paired Pulse Facilitation in the Normal and Sprouted Crossed Temporodentate Pathway in Rats

Stephanie L. Courchesne, Jennie R. Hillman, Jennifer L. Caldwell, and Julio J. Ramirez

Alzheimer’s disease (AD) is a neurodegenerative disorder primarily characterized by memory deficits.  The cellular pathology of AD effectively disconnects the hippocampus from the remainder of the cortex.  In rats, unilateral entorhinal cortex lesions mimic the memory deficits seen in patients with AD.  These deficits are ameliorated by sprouting of the crossed temporodentate (CTD) pathway.  In this study, the electrophysiological capabilities of the CTD were investigated using the paired pulse paradigm at interpulse intervals of 10-100 ms.  Male Sprague-Dawley rats were assigned to one of four groups: 1) one-stage lesion, 2) progressive lesion, 3) priming lesion, or 4) intact control.  Progressive lesions have been shown to accelerate sprouting and behavioral recovery.  Electrophysiological recordings of the CTD were taken at 4 days post-lesion.  At this

time point, paired pulse facilitation was evident in the progressive lesion group, but not in the one-stage lesion group.  No reliable facilitation was observed in either the priming lesion group or the intact controls.  Previous studies have shown that animals with progressive lesions show recovery of memory function at 4 days post-lesion, while animals with one-stage lesions do not.  These results are consistent with the hypothesis that short-term synaptic events, such as paired pulse facilitation, contribute to memory function.  

Flashbulb Memories in Older and Younger Adults

Joy Gerdy

This study investigated older and younger adults’ memories for the circumstances in which they heard the news of the September 11 attacks, and for their ratings of emotions for that time.  Researchers interviewed 65 community-dwelling older adults (at least 60 yrs old) and 66 younger adults (undergraduates) by telephone within 1 week of the attacks and approximately 21 weeks later.  Flashbulb memories are accurate recollections of the circumstances under which one heard significant news.  Only 20% of older adults and 24% of younger adults showed flashbulb memories.  Younger adults remembered their emotions more accurately than older adults.  The effects of gender, personal ties to the attacked cities, and rehearsal frequency are also reported.

Depression and Anxiety in Chronic Obstructive Pulmonary Disease Patients: An Examination Using the University of California at San Diego’s Shortness of Breath Questionnaire

Cort Heroy

Sufferers of chronic obstructive pulmonary disorder (COPD) suffer also from depression and anxiety, but no direct correlations with a cause have been made. This study examined depression, anxiety, and dyspnea in COPD sufferers. Participants were 55 outpatients from the Presbyterian Hospital Cardiopulmonary Rehabilitation Facility. Participants were given the SCL-90R, SF-36, and the UCSD SOBQ, a subjective score of breathing distress. Depression and anxiety sub-scores from the SCL-90R were compared to SOBQ using ANOVA, MANOVA, and linear regression tests. Depression and anxiety sub-scores from the SCL-90R were positively correlated with scores on the SOBQ. This suggests that dyspnea could be a contributing factor in the depression and anxiety seen in COPD patients; however, further tests need to be conducted due to a lack of power in the current study.

The Effects of Outdoor Based Experiential Training on Employee Self-Esteem

Anna Joyce

The purpose of the present study was to examine the effects of outdoor-based experiential training (OBET) on employees of an organization.  Using a within-subjects design, self-esteem was measured for five employees out of a 20-member group before and after they spent one day on a challenge course as a part of a program to facilitate organizational change in their company.  Global self-esteem was measured using the Rosenberg Self-Esteem Scale and situational self-esteem was measured using the Organizational-Based Self-Esteem (OBSE) Scale.  Results showed that global self-esteem was not significantly affected by OBET, but that organizational self-esteem was, indicating the necessity of a situational-specific self-esteem measure as well as the usefulness of OBET in organizational development. 

Sensitivity to the Antinociceptive Effects of Kappa Opioids in Rats With Free Access to Running Wheels

Jacob McClean

Running has often been reported to cause feelings of euphoria, increased pain thresholds, and decreased sensitivity to the effects of exogenous opioids.  These effects are presumed to be due to the prolonged release of endogenous opioid peptides during vigorous exercise.  Indeed, it has been shown that rats with free access to running wheels display both increased pain thresholds and a decreased sensitivity to the antinociceptive effects of µ opioids.  The present investigation examined the antinociceptive effects of the κ opioids spiradoline, U69,593 and U50,488 in Fischer 344 rats with free access to running wheels.  To this end, one group of rats was housed in cages equipped with running wheels, and another group was housed in cages absent of running wheels.  The antinociceptive effects of κ opioids were tested in running and sedentary rats using the warm-water, tail-withdrawal assay.  Following the conclusion of the testing period, running wheels were removed from the cages of running rats and symptoms of withdrawal were examined.  It was found that running and sedentary rats displayed similar baseline pain thresholds.  Furthermore, running and sedentary rats showed similar sensitivities to the antinociceptive effects of spiradoline, U69,593 and U50,488.  Upon removal of the running wheels, no symptoms of withdrawal were observed.  Therefore, we conclude that free access to running wheels does not alter pain threshold or sensitivity to the antinociceptive effects of kappa opioids in the warm-water, tail-withdrawal assay.

The Relationship Between Coping Behaviors and Leadership Behaviors Among Managers and Executives: Effects of Gender and Age Differences

Renee Miller

Gender and age differences in the relationship between coping ability and leadership practices for organizational leaders were investigated using the Ways of Coping Questionnaire (WOC) and the Leadership Practices Inventory (LPI).  Participants included 8 women and 21 men (mean age = 43.2 years) in positions from manager to CEO.  The hypothesized positive correlation between coping effectiveness and leadership ability was partially supported.  While hypothesized gender differences in use of specific leadership practices and coping strategies because of stereotypes were not completely supported, significant gender differences in WOC subscale scores were found.  Hypothesized age differences for women were not supported, but age differences were found for men.  Overall, the data support the notion that the relationship between coping and leadership is different for men and women, particularly in terms of particular subscales (i.e. Planful Problem Solving and Encouraging the Heart).

Briefly Flashed Objects: Push or Pull?

Ryan Owens and Margaret P. Munger

When asked to remember the location of a flashed object that is actually aligned with a moving object, the flash appears to lag behind (FLE).  FLE seems to depend on the moving object’s continued presence (Experiment 1).  Representational momentum (RM) is a memory distortion where the final orientation of a moving object is misremembered as further along the trajectory.  When participants judged the position of a spinning rod with or without an additional flashed object, RM was observed all conditions.  Larger RM was observed for downward rotations, suggesting sensitivity to gravity.  The addition of the flashed object led to even larger downward memory distortions, suggesting that the RM task provides sufficient illusory motion to produce FLE.

Can a Generation Effect be Found in an Event-Based Prospective Memory Task?

Julia Philpott

This research focuses on whether a generation effect (better retention for self-produced items over presented items) could be found in both retrospective memory (RM; memory for what to do) and prospective memory (PM; memory to do something) components of an event-based PM task.  Undergraduates (N = 32) were assigned to 1 of 4 experimental groups (generated RM cue, generated PM cue, read both cues and generated during filler RM tasks, no generation).  Participants completed a short–term word retention task while simultaneously completing a PM task of monitoring a target word.  Filler RM measures were free and cued recall.  No measures showed a generation effect.  Results are discussed in terms of the relationship between RM and PM.

Children’s Reliance on Paralinguistic and Facial Cues in Judgments of Emotions

Elena C. Sakkalou

The study examined children’s understanding of emotions in two tasks.  In Task 1, 5-, 7-, and 12-year-old children (N = 23) judged the emotion (happy, sad, and neutral) portrayed by 2 characters’ paralinguistic (vocal features that accompany speech e.g., tempo and loudness) and facial expression cues.  When the cues conflicted, (i.e., the character had a happy facial expression but expressed a neutral lexical sentence in a sad tone), children found the facial expression more salient than the paralanguage.  In Task 2, children watched the conflicting cues again and were asked to provide reasons for the answers they had given.  For all age groups, focus on facial expression was greater than focus on reasons mentioning lexical cues and reasons mentioning facial and paralinguistic cues together.  The findings support children’s limited understanding of the role of vocal emotion in communication. 

Forgiveness, Coping Patterns, and Physical Health in HIV-Positive Individuals

Lauren Snyder

Twenty-two HIV-positive outpatients were given a set of vignettes measuring 5 different types of forgiveness, the Ambivalence Over Emotional Expression Questionnaire (AEQ), the State-Trait Anger Expression Inventory (STAXI), and a questionnaire assessing coping behaviors.  Objective measures of physical health were also obtained.  Self-forgiveness was negatively correlated with the AEQ scales and the internal anger expression scale of the STAXI, which were negatively related to CD4 cell count.  Feeling forgiven in the interpersonal context was also negatively correlated with an AEQ scale.  There were significant positive relationships between different types of forgiveness and social support and healthy behavior ratings.  These findings support a model of forgiveness as a process of transformation mediated by the dissolution of Type A and Type C coping patterns, resulting in better coping and better health. 

The Psychosocial and Metabolic Effects of Multiple Daily Injections and Insulin Pump Treatments for Children and Adolescents with Type 1 Diabetes

Melanie Wadkins

This study examined the metabolic and psychosocial effects of Continuous Subcutaneous Insulin Infusion (CSII) on children and adolescents with Type 1 diabetes compared to a group of diabetic children and adolescents treated with multiple daily injections (MDI) of insulin.  The participants included 35 children (13 boys and 22 girls aged 8-18) using CSII treatment (n = 17) and MDI treatment (n = 18).  Using psychosocial measures quantifying family functioning, ability to cope with diabetes, depression, quality of life, and self-efficacy, results prove that CSII is a treatment comparable to MDI for children of all ages.  The goals of this study were to replicate and extend previous research including younger children to provide evidence that the use of insulin pump can be beneficial, medically and psychologically, to adolescents and preadolescents and have positive impacts on family functioning.  This study demonstrated that good family functioning is closely linked to better metabolic control for patients having recently begun CSII treatment.


We thank the Departments of Biology, Chemistry, Physics, and Psychology for jointly funding this event.

We thank Central Services for printing this brochure and Dining Services for catering this event.

We thank all student presenters for their efforts and hard work, and faculty mentors for their time and guidance.

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