Fairfield University Chapter
Sigma Xi, The Scientific Research Society


Bannow Science Center MacDonnell Atrium and Second Floor
Wednesday, April 26, 2006
3:00 p.m. to 5:00 p.m.

Rachel Abenavoli ’07, Andrea McCarthy ’06, Marion Schimpf ’07, Sophia Velez ’06, and Chrissy Young ’07
Advisor: Elizabeth Gardner, Ph.D., Fairfield University

The cross-race effect
Previous research on the cross-race effect (also known as the same-race bias) has shown that individuals are able to recognize faces of people belonging to their own race much better than they are able to recognize faces of people belonging to other races. While the cross-race effect may be influenced by the frequency with which a person comes into contact with faces of a certain race or by differences in the underlying perceptual processes used to code same and other-race faces, our study examined the possible relationship between prejudicial attitudes and the ability to recognize faces. Thirty Caucasian undergraduates from Fairfield University were presented with 20 faces belonging to Black individuals and 20 faces belonging to White individuals. Following this first presentation and a filler task, participants were presented with another 40 faces, half of which were taken from the first phase, and were instructed to determine whether or not the faces had been presented during the first presentation of faces. Each participant then completed a Race Implicit Associations Test in order to gauge any automatic preferences for White versus Black faces. People accurately recognized significantly more White faces (75.35% accurate) than Black faces (65.83% accurate). However, the Implicit Associations Test was not an accurate predictor of the cross-race effect. The findings have applications to the eyewitness testimony debate, as well as to daily patterns of interaction with members of other races.

Caroline Agin ’06 and Lauren Blanchette ’06
Faculty Advisor: Shannon Harding, Ph.D., Fairfield University

Using a one day morris water maze test for memory and visual acuity in middle aged and old aged enriched mice
The current study was part of a collaborative effort with the Biology Department to investigate the role of peroxiredoxins in the memory decline in mice. Female mice were housed in an enriched environment upon arrival to the lab until reaching 10 months (middle age) or 22 months (old age). A one-day Morris water maze test was developed by the students for the purpose of this study. Mice were initially trained to reach a submerged platform, and spatial memory was assessed by measuring the time to reach the platform when animals were dropped from multiple locations. To confirm that the differences in swim time were due to spatial memory decline and not visual impairments, a visual acuity test was performed at the end of the data collection. Based on previous research, it was hypothesized that middle-aged mice would learn to reach the hidden platform sooner than old-aged animals. However, no significant differences were observed between groups in terms of swim time. This suggests that the groups were not dramatically different in terms of spatial memory ability, yet we did observe considerable variability between animals. After sacrifice, brains were removed and examined by the biology department for changes in peroxiredoxin, a protein that is reported to have protective effects on cells.

Caitlin Bickhart ’06
Faculty Advisor: Glenn R. Sauer, Ph.D.

The effect of metallothionein-inducing agents on cell viability and detection of apoptosis in human articular chondrocytes
Articular chondrocytes, cells that maintain the matrix of joint cartilage, have been found to undergo apoptosis when exposed to some cytotoxins. It has been found that exposure to metallothioneins prior to treatment with cytotoxins leads to a lower percentage of cell death (Sauer et al., 1998). Detection of cell death can be achieved with the lactate dehydrogenase(LDH)-release assay, while the detection of apoptotic cells requires the caspase-3 fluorimetric assay. In this study, human articular chondrocytes were treated with varied concentrations of the cytotoxins etoposide, staurosporine, cycloheximide, actinomycin, dexamethasone, sodium nitroprusside, hydrogen peroxide, and glucose oxidase. A control LDH-release assay was performed; an additional trial tested for metallothionein activity by treating cells with dexamethasone, cadmium, or zinc, allowing the metallothionein inducing treatments a 24 hour induction period, then adding the cytotoxins. The caspase-3 assay showed staurosporine and glucose oxide-treated cells resulting in slightly elevated levels of caspase-3 activity after 3 hours. In contrast, most reagents resulted in cytotoxicity at the concentrations tested as indicated by the LDH-release assay. Pre-treatment of cells with metallothionein inducing agents resulted in lower levels of cytotoxicity. It was concluded that there were only slight levels of apoptotic chondrocytes with exposure to cytotoxins, and that there is a possible linkage between metallothionein activity and cell viability.

Janelle Buckley ’06 and Patrick Dameron ’06
Faculty Advisor: Jerry Sergent, Ph.D.

When an individual’s heart rate becomes irregular or unstable, there is a need to quicken the response of medical personnel
When an individual’s heart rate becomes irregular or unstable, there is a need to quicken the response of medical personnel. In the case of a person with heart disease, if their heart rate becomes irregular or unstable due to a variety of conditions, for example a heart attack, the heart monitor will alert the proper medical personnel. Minimal individual involvement is necessary, when alerting medical personnel. Once the individual’s the heart rate goes either above or below the preprogrammed parameters, a signal will be sent to a device which will automatically contact medical personnel. The medical personnel will receive a call which will inform them of both the heart rate, and the individual’s location due to an attached locator system.

This device is only meant to alert medical personnel, in an attempt to quicken their response time. It is not intended to prevent a heart attack, or administer treatment to the individual’s heart. Approximately 250,000 people die per year of a heart attack before reaching a hospital. (Bianco, 10) Implementation of the device is intended to aid, and to quicken the response of medical personnel.

We have chosen all the necessary components. We are using the Polar FS3 heart monitor and the Boost Mobile i415 cell phone with GPS capability. We are currently in the integration phase of the project. Due to time constraints, and unavailability of resources from the cell phone manufacturer, the requirements of the design were slightly changed. The new proposed design includes automatically placing a phone call to medical personnel once the heart monitor detects a heart rate above or below the preprogrammed parameters.

Nicole Carlson ’06 and Maggie Wollschlager ’06
Faculty Advisor: Shelley Phelan, Ph.D.

Analysis of Peroxiredoxin Expression in Aging in Mouse
Peroxiredoxins are a family of antioxidant proteins which utilize cysteine residues to reduce peroxides in the cell. There have been six peroxiredoxin family members identified in mammals, which are differentially expressed in a wide variety of tissues. Peroxiredoxin expression was recently detected in brain tissue and found to be differentially distributed based on cell type, suggesting a specific role for individual peroxiredoxins in neural function. Many studies have also shown a close correlation between the aging process, age-related disease and oxidation. Based on the differential expression of peroxiredoxins in the brain, as well as other tissues, and the known role of antioxidants in aging, we hypothesized that peroxiredoxins would be differentially regulated in different aged mice. RNA was extracted from brain and liver of middle and old aged mice, and gene expression was analyzed for individual peroxiredoxins, specifically Prdx1, Prdx2, and Prdx6. Expression was assayed using a one-step RT-PCR method. We successfully purified intact RNA from all tissues. From our data, we have concluded that there is no difference in expression levels of Prdx6 or Prdx2 in the brain or liver at different ages. Expression of additional peroxiredoxins is currently being measured. Changes in antioxidant expression in brain tissue could indicate a potential role in neurodegenerative diseases.

Jessica Cataldo ’06
Faculty Advisor: Linda Henkel, Ph.D.

Unintentional plagiarism
People can sometimes come to believe that they have performed actions or made statements that they did not in fact do. This study looks at how and why people take credit for ideas that are not their own (i..e., unintentional plagiarism). Under what conditions is inadvertent plagiarism more likely to occur? The study examines whether people are selective in the information that they inadvertently use and claim to be their own, which would have important implications for understanding the cognitive processes that give rise to such memory failures. Specifically, the aims are to determine if people are more likely to claim as their own ideas that they believe are more attractive (e.g., more popular, more credible, or more desirable). In addition, the study addresses whether certain aspects of personality are related to occurrences of unintentional plagiarism, such as suggestibility, compliance, and creativity. Participants were presented with a series of ideas from other people that were possible solutions to the issue of recycling on the Fairfield University campus. They were then asked to generate their own ideas for the same problem. One week later, they were asked again to generate new ideas regarding the same issue, and their memory for the source of the ideas they read or generated a week ago was also assessed. Standardized measures of suggestibility and compliance were administered, as well a self-developed creativity scale. Data collection is still underway, and completed analyses will be presented at the poster session. It is hypothesized that participants will be more likely to claim as their own ideas that were said to be more popular or frequent, ideas that were from a more credible source, and ideas that were better or more desirable than unpopular, noncredible, or undesirable ideas. In addition, it is expected that more suggestible people, more compliant people, and less creative people will plagiarize more often than other participants.

Jessica Curtis ’06
Faculty Advisor: Laura McSweeney, Ph.D.

Statistical Analysis and Survey Techniques
For my Honors thesis project, I have been working on an independent statistical analysis project under the supervision of Dr. Laura McSweeney. I began by generating an unbiased survey following the guidelines of how to create a survey without inference or bias, and then conducted this survey independently to collect raw data. In learning the techniques of generating a good survey, I was able to analyze and critique the research, sampling, and analysis techniques used by the popular college rank guide The Princeton Review. My specific area of interest in creating this survey was to test the student body on campus to analyze the views of the academic and/or social life offered at Fairfield University based on their experience. Throughout this independent study, I was able to learn and use new statistical software programs such as SPSS to organize my data and conduct statistical analysis, which I will then be discussing in a full report by the end of the term. I intend to present my preliminary findings from my research today.

Bryant Duda ’06
Faculty Advisor: Dorothea Braginsky, Ph.D.

Protestant Ethic and Locus of Control in College Students: A comparison from the 1970s to present
A comparison of college students over time (decades) of their perceptions of Locus of Control and the importance of Protestant Ethic in their lives. Analysis will be questionnaire data obtained from Fairfield University and from two earlier cohorts.

Bryant Duda ’06, Kristina Chomick ’06, Jamie Versace ’07, Cagney Rignaldi ’07
Faculty Advisor: Dorothea Braginsky, Ph.D.

The Protestant Ethic and Locus of Control in College Students
The research consists of surveys and interviews which were conducted to determine the degree to which one’s gender and major (business vs. non-business) affects their locus of control and Protestant Ethic.

Bridget Gallagher ’06
Faculty Advisor: Shelley Phelan, Ph.D.

Regulatory Elements of Prdx6 Transcription
Peroxiredoxin 6 (Prdx6) is a member of the peroxiredoxin family of antioxidant molecules, which protect cells by reducing cellular peroxides produced by normal cellular metabolism. It has been shown that peroxiredoxin 6 is widely expressed, with highest expression in the liver. Previous studies from our lab have demonstrated that Prdx6 expression is down regulated with serum deprivation, and up-regulated in a time-dependent manner in response to various soluble ligands. In order to determine the regulatory elements that mediate basal and induced expression, we generated reporter constructs containing regions of the Prdx6 proximal promoter, and tested them in transient transfection assays. We first tested and optimized the lipofectamine method of transfection and a colorimetric assay for reporter expression. We then analyzed the immediate proximal promoter for ability to drive reporter expression in the absence and presence of inducers. We hypothesized that this 160 base pair sequence would be necessary and sufficient to mediate growth-regulated expression. We found that this region mediates high expression in growing cells and down-regulation in serum-deprived cells. Our data suggests that this region may also mediate ligand-induced expression, however further studies are required. Future studies aim to investigate additional upstream regulatory regions of Prdx6. Further investigation of Prdx6 may have implications for age-related diseases, as antioxidant molecules have been shown to play key roles in the prevention of such diseases.

Tara Hansen ’06, Joe Griffin ’06, Scott Davidson ’06, Trevor Kelly ’06
Faculty Advisor: Alan Dubrow and Clem Anekwe, Ph.D.

Renewable Hydrogen Energy
The system takes water and breaks it down into hydrogen and oxygen. The oxygen is vented out of the system while hydrogen is stored in tanks which ultimately go into the fuel cell. This system is solar powered. We helped fix a plumbing problem by raising a KOH separator. Also, we designed a new pumping system that is powered by a hydraulic/pneumatic system that would replace the existing pump if the budget would allow. We are fixing the efficiency of the system by heating the cells to its optimum temperature, which will be determined with testing. This is being done by converting a heater that is sparkless with a platinum catalytic heater to run off of hydrogen produced by the system.

Stephanie Hohler ’06
Faculty Advisor: Linda Henkel, Ph.D.

Older and Younger Adults’ Memories for Pictures
Prior research has shown that older adults often tend to remember more positive events and information, whereas younger adults tend to remember more of the negative. Carstensen’s (1987, 1991, 1993) socioemotional selectivity theory postulates that older adults pay attention to and selectively remember more positive information because it is more important for people closer to the ends of their lives to maximize positive experiences. The present experiment examines whether older adults systematically bias their memories in favor of positive information when they are asked to repeatedly remember as much as they can. Older (65 and up) and younger (18 – 23) adults were shown a series of positive, negative, and neutral pictures and then were asked to recall the pictures on three separate occasions. The context and motivation for the repeated recall tests were manipulated by using a standard recall procedure that simply asked the participants to recall the pictures and an assisted recall procedure that gave the participants an incentive, such as their family or friends wanting a list of the pictures. Data collection is still underway. Results are expected to show that older adults will remember more positive pictures on the final recall test, whereas younger adults will remember more negative pictures on the final recall test. Futhermore, results from a later old/new recognition test are also expected to show this age-related positivity bias. Additional analyses will determine whether individual differences in participants’ future time perspective mediate this positivity bias.

Hien T. Le ’06
Faculty Advisor: Jen Klug, Ph.D

Effects of variation in nitrogen and phosphorus ratios and concentrations on cyanobacteria heterocysts frequency
Nitrogen fixation is a process used to convert nitrogen gas, an unusable form to a useable form, ammonium. Cyanobacteria are known for this capability. Aphanizomenon and Anabaena are examples of these cyanobacteria species. Nitrogen fixation takes place in a specialized cell on each filament known as the heterocyst. Under circumstances when nitrogen is low, Aphanizomenon and Anabaena have a competitive advantage over other phytoplankton species because they can fix nitrogen on their own. In this project, I have been looking at water samples from Lake Lillinonah for year 2003, 2004, and 2005. The method used to prepare the sample for enumeration under an inverted microscope is Utermohl. This project looks at the relationship between heterocyst frequency versus the nutrient chemistry and how heterocyst frequency changes over the course of the summer.

Daniel Levesque ’06
Faculty Advisor: Phyllis Braun, Ph.D.

Effect of ECGC and ECG on the formation and destruction of biofilms produced by Candida albicans
Previous experiments have shown that crude green tea extract (GTE) effectively destroys biofilms produced by the yeast C. albicans. Two different strains, 10231 and 4918, were separately tested in this experiment. Two catechins found in GTE that could be responsible for its antifungal properties were examined. Those two chemicals were epigallocatechin-gallate (ECGC) and epicatechin-gallate (ECG). Polyphenol extract that contains ECG and ECGC was also used. These chemicals were added at various concentrations to a microtiter plate containing C. albicans in order to prevent the formation of biofilms. Further experiments determined whether the two chemicals destroyed preformed biofilms as well. The density of the biofilms was measured using calorimetric assay based on the metabolic activities of the biofilm formation. ECGC, ECG, and polyphenol was hypothesized to both prevent the growth of biofilms and destroy preformed biofilms. Both strains of C. albicans showed an average decrease of 66% in biofilm formation when these chemicals were added to the growing form of C. albicans. Treating preformed biofilms with these polyphenols for 6 hours unexpectedly appeared to allow continued growth of these biofilms. This should be retested to confirm these unexpected results.

Samantha Lipinsky ’06
Faculty Advisor: Jen Klug, Ph.D.
Project Advisor: Susan Quincy, Connecticut Department of Environmental Protection – Kellogg Environmental Center

Eastern Bluebirds (Sialia sialis)
Eastern bluebirds suffered a population decline due to the depletion of nesting space. The decrease in viable nesting space is due to many factors, which include urbanization, pesticide use and competition with nonnative species. Organizations such as the Connecticut Department of Environmental Protection have developed a nest box program to provide possible nesting space for the Eastern bluebirds. Many factors are considered when setting up the nest boxes. For example, the distance of a nest box from wooded areas and from other nest boxes must be carefully considered in order to create the best nesting space. Once the nest boxes are set up they are monitored regularly. When found, the nests and any eggs of nonnative birds like the European starling and house sparrow are removed from the boxes. Even with human intervention it is possible for the Eastern bluebirds to lose the nesting space to other native birds. Approximately one third of the nest boxes contain an old nest. These nests were left in the boxes to see if birds prefer nest boxes that are empty or boxes that contain a nest. Any observations and data that are collected are submitted to the Connecticut Department of Environmental Protection and the Cornell Ornithology Laboratory for further study.

Nora Lopez ’03
Faculty Advisor: Olivia Harriott, Ph.D.

Sponge-bacteria symbionts
Phylogenetic and microscopic studies by others have demonstrated that marine sponges host a large diversity of transient and symbiotic microorganisms. Several members of the sponge-symbiont communities may belong to a monophyletic lineage of sponge specialists (e.g., Fieseler et al. 2004). In this study a molecular approach was used to characterize 16S rDNA gene sequences of Bacteria harbored by the Caribbean marine sponge Chondrilla nucula collected in the Florida Keys. Using domain-specific primers, 16S rDNA gene libraries of C. nucula were constructed and compared to a clone library of bacterioplankton from the surrounding water. Diversity was estimated using amplified ribosomal DNA restriction analysis (ARDRA) patterns of clones that were generated with HpaII and HhaI. Rarefaction analysis was used to estimate species richness in these communities based on combined, unique ARDRA profiles. The results show that the majority of bacterial clones in the C. nucula library (>95%) were not detected in the bacterioplankton library. The symbiont community appears to be relatively stable because several bacterial species were identified when ARDRA profiles generated from two different C. nucula sponge libraries created in 2002 and 2004 were compared. Furthermore, as indicated by 16S rDNA sequences, our data supports the hypothesis (Hentschel et al. 2002) that sponges living in tropical oceans separated by 104 km harbor a subset of highly specific bacteria.

Carolyn Manning ’06
Faculty Advisor: Elizabeth Gardner, Ph.D. and Sue MacAvoy, Ph.D.

Stereotypes and attitudes towards housed people
To test my hypothesis that people who are homeless have generally negative or pessimistic stereotypes, attitudes and opinions about people who are housed, 27 program participants from two homeless shelters in Connecticut were given a questionnaire. This was comprised of 26 statements / questions. Participants were asked to circle a number, one through seven, to indicate degree of agreement where one was the strongest disagreement and seven was the strongest agreement. These statements / questions themselves probed opinions, attitudes and behaviors of the participants of the survey towards housed people. There were generally positive and optimistic responses from the participants as measured by their means and standard deviations. My hypothesis was not supported here. In this work, a number of possible reasons for the positive responses are given, as well as implications and uses from the results of the survey.

Christopher Miller ’06
Faculty Advisor: Stephen Sawin, Ph.D

Knot Theory
The mathematical theory of knots has numerous applications to many areas of science. Knot theory is useful in the study of genetics, string theory, and quantum computing. The seemingly disparate nature of these three areas in which knot theory is useful is a testimony to the power of knot theory. We will present an overview of some of these applications within the context of introductory knot theory, as well as demonstrate some current research on the Jones Polynomial, an important property of knots.

Anne Morris ’06
Faculty Advisor: Tod Osier, Ph.D.
Program Advisor: Colin Campbell, Ph.D. at the University of Minnesota

Deficient DNA repair in a cell culture model of Fanconi Anemia
Fanconi anemia (FA) is a genetically heterogeneous fatal disease afflicting mainly children. There is an emerging consensus that the bone marrow failure and cancer predisposition associated with this disorder result from defective DNA repair. Several lines of evidence suggest that this defect involves the evolutionarily conserved Rad50-dependent DNA end-joining pathway. To test this hypothesis, a transgenic FA cell culture system was created. Human fibrosarcoma-derived HT1080 cells were transfected with a disease-causing allele of the FA ‘C” gene, and a stable cell line called L554P was isolated. Analysis revealed that nuclear protein extracts from the transgenic L554P cells displayed reduced levels of DNA end-joining activity, compared to extracts from un-modified HT1080 cells. In addition, extracts from the L554P cells had significantly less DNA tethering activity than did extracts from control cells. These results support the working hypothesis that FA cells fail to activate the Rad50-dependent DNA repair pathway. Our long term objective is to understand why this pathway of DNA repair is inactive in FA cells in order to facilitate the development of a drug to treat FA patients.

Stephanie Serpa ’06
Faculty Advisor: Shelley A. Phelan, Ph.D.

Analysis of Peroxide in Mouse Liver
Hydrogen peroxide (H2O2) is known as a reactive oxygen species (ROS). ROSs form as a natural byproduct of the normal metabolism of oxygen but can damage proteins, DNA, and cell membranes through oxidation. Interestingly, H2O2 has been shown also to play a significant role in cellular signal transduction. Peroxiredoxin 6 (PRDX6), is a member of the peroxidredoxin antioxidant family of enzymes. This antioxidant family shares the ability to reduce H2O2 to water, protecting the cell from oxidative damage. Since PRDX6 is highly expressed in the liver, we sought to determine if hydrogen peroxide levels in liver would vary under different oxidative-stress conditions in mice. We first tested a peroxide-detection assay to determine quantitative levels of aqueous and lipid peroxides. We then prepared liver lysates from mice under different conditions. We compared the effects of high fat diet, PRDX6 knockout, and age on aqueous peroxide levels. We hypothesized that all three conditions would increase oxidative stress in the liver, resulting in an increase in aqueous peroxide levels. Values from this assay were recorded and compared. The Bio-RAD protein assay was then used to quantify the amount of protein obtained in each mouse liver lysate, in order to standardize samples. We found that both aqueous and lipid peroxides can be accurately measured by this method, although a different technique is required for extraction of lipid peroxides from tissue. We are currently comparing H2O2 levels between samples. Further analysis will be required to determine the relative amount of PRDX6 in each of these tissues, and to investigate a correlation between H2O2 levels and the amount of PRDX6.

Mike Shinall '07
Faculty Advisor: Matt Kubasik, Ph.D.

Hydrogen/Deuterium Exchange Studies on Two Short Peptides
Hydrogen/Deuterium Exchange (HDX) experiments are commonly used to investigate the stability and conformational excursions of biomolecules such as proteins, DNA, RNA and peptides. We have conducted an HDX study on two short peptides in an effort to characterize the stability of their short helical structures in solution. Intramolecular hydrogen bonds maintain the integrity of the helical structure, and these hydrogen bonds exist in a bonded/non-bonded equilibrium. Non-hydrogen-bonded amide protons are susceptible to exchange, whereas hydrogen-bonded amdie protons are protected from exchange. By measuring the rate of exchange, we can determine the relative stabilities of specific hydrogen bonds in our peptides.

Maliha Siddiqui '06
Faculty Advisor: Edmond J. O'Connell, Ph.D.

Detection of Ketene Intermediates in the Phaotolysisof cis-1,2-dibenzoylethylene
c is-1,2-dibenzoylethylene is known to undergo a photochemically induced rearrangement. It is strongly suspected that there are conjugated ketene intermediates involved in this reaction. It is our goal to characterize these ketenes using proton NMR.

Alison Sikora ’06
Faculty Advisor: Glenn Sauer, Ph.D.

Induced metallothionein gene expression in human chondrocytes by metal exposure
Previous studies have suggested that metallothionein expression in human cells can be induced by metal exposure. Expression of the metallothionein gene in human chondrocytes has been observed to delay the onset of apoptosis in such cells. Metallothionein is a cysteine-rich, low molecular weight intracellular zinc binding protein. Production of this protein, due to metallothionein gene expression, provides resistance to cellular oxidants by scavenging free radicals. Therefore, by buffering the amount of reactive oxygen species, the onset of apoptosis can be delayed. Apoptosis of human adult chondrocytes can ultimately lead to cartilage degeneration, thus resulting in debilitating conditions such as osteoarthritis and osteoporosis. The present study seeks to determine which metals, and in which optimal concentrations, can best induce the expression of metallothionein in human chondrocytes. Human chondrocyte cell lines were maintained in both adhesion and suspension cultures, treated with various metals, and then harvested 48 hours later. Extraction of cellular RNA, followed by RT-PCR, allowed for metallothionein expression to be observed via gel electrophoresis. Qualitative comparative analysis permitted the observation of metallothionein expression depending on the various metals that were previously exposed to the cells. Consistent with results from similar studies, both high and low concentrations of cadmium metal induce gene expression of metallothionein, thus suggesting that diets high in this metal may delay the onset of apoptosis in human chondrocytes. Furthermore, high concentrations of zinc also appear to induce metallothionein expression. The results from this study suggest that cadmium and zinc metals may play an essential role in the integrity of adult chondrocytes by inducing metallothionein gene expression and thus preventing the rapid degeneration of cartilage tissue in aging human beings.

Danielle Spears '06
Faculty Advisor: Olivia Harriott, Ph.D.

Analyzing Microorganisms that live in the Marine Sponge, Chondrilla nucula
Previous studies have shown that marine sponges are home to many different microorganisms. The microorganisms present in the sponge may protect the sponge from disease. The microorganisms may also provide nutrients to the sponge. The research I conducted focused on characterizing the microorganisms that live symbiotically within the marine sponge Chondrilla nucula. Polymerase chain reaction (PCR) was performed on total sponge community DNA using bacterial rRNA primers to selectively amplify 16S rRNA genes of bacterial representatives in the community DNA sample. Six rRNA gene fragments derived from PCR were subjected to DNA fingerprinting and the DNA sequences of two rRNA gene fragments. Based on the phylogenetic analysis of bacterial rRNA gene fragments derived from Chondrilla nucula community DNA (this study) and other marine sponges it appears that bacteria related to the Acidobateria and Proteobacteria are commonly found in diverse marine sponges.

Michael Talmadge ’07
Faculty Advisor: Jack Beal, Ph.D.
Project Sponsor: National Science Foundation

Solid State Physics
Modeling electron diffusion in semiconductor materials and developing methods for determining material parameters from experimental data through use of numerical methods.

Melissa M. Wright ’06
Faculty Advisor: Linda A. Henkel, Ph.D.

Emotional Bias in Source Attributions for Young and Older Adults
Older adults often exhibit a positivity bias – a tendency to attend to and remember more positive than negative information. The present study examined whether older adults would systematically remember more positive than negative information over a series of successive recall tests and would be more accurate at remembering the source of positive information. While using full or divided attention, young and older adults encountered positive, negative, and neutral words said by two different people. Shortly after, they recalled the words 3 separate times and then indicated the speaker of each remembered word on a recognition test. Results showed higher recall rates for young than for older adults, though overall levels of recall were relatively low for both groups and favored negative over positive words. Older adults did not show any systematic increase in recall across the successive tests, and this was true for those who encoded the words under full attention as well as those who encoded words under divided attention. Young adults under full attention at encoding recalled more words on the 3rd test than on the 1st test, whereas young adults under divided attention showed the same lack of an increase as did older adults. Older adults under full attention and young adults under divided attention showed a positivity bias in their source attributions, with fewer source errors in claiming one person said the word when the other person did for positive words than for negative words. In contrast, young adults under full attention and older adults under divided attention showed the opposite pattern: more source errors for positive than for negative items. The role of attentional and memory processes in regulating emotional well being are discussed in light of these findings.

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