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Senior Thesis Previews: What Some Science Majors Are Researching for Their Final Projects
October 30, 2009Making an ADHD Model in Rats Using Dopamine
by Sam Colalillo '10Neuroscience Major
For my senior thesis, I am working with Professor Weldon to make an ADHD model in rats. ADHD is thought to involve a deficit of dopaminergic activity in the brain and current treatment involves drugs that increase dopamine. Currently, ADHD models in rats completely deplete dopamine or lead to long-term behavioral deficits unassociated with ADHD that give these models little face validity.
For my thesis, we are working on a model that uses the interaction between drug treatment and the developmental stage of a rat to generate rats that function normally, but show the symptomatology of ADHD. Specifically, we are using apomorphine, which simulates dopamine, to treat rats during development. We hope this will create deficits in the dopaminergic system that result in an ADHD-like rat. We are using motor activity testing as well as spatial memory and object discrimination to characterize the rats as showing symptoms like those of ADHD.
Inhibitors for Galectin-1, Which May Be a Factor in the Spread of HIV and Cancer
by Sara Miller '10Biology Major
My thesis is focused on the protein galectin-1, a molecule expressed on cell surfaces that plays a role in cell signaling and cell adhesion. Recently, galectin-1 has been implicated in the spread of cancer throughout the body (metastasis) and HIV infectivity.
The goal of my thesis is to synthesize organic molecules that will function as potential inhibitors of galectin-1. Once synthesized, the inhibitors will be tested with galectin-1 to evaluate how well they bind to the protein. The inhibitors that bind the strongest to galectin-1 will therefore serve as the optimal inhibitors.
In order to determine what kind of inhibitor will have the strongest binding interaction, a number of molecules will be synthesized that vary in terms of flexibility, polarity and aromaticity. Galectin-1 binds preferentially to tetrasaccharides (carbohydrates with four subunits), so the inhibitory molecules will mimic this structure.
Each inhibitor will be built off of lactose, a carbohydrate with two subunits. Two additional subunits will be added through synthesis: a five membered ring containing nitrogen (known as a triazole) and a variable group, which differ based on the criteria discussed above. The synthesis and purification of inhibitors is almost finished, and the remainder of the semester will be dedicated to evaluating their binding potential. Next semester, I will focus on a slightly different type of inhibitor and hopefully conclude with a comparative library of all the inhibitors synthesis.
Changing Mass Balance of Ice Shelf Using cGPS Data from Palmer Station
by Mason Fried '10Geoscience Major
My senior project involves looking at crustal rebound as a diagnostic for regional climate change and as a constraint for reconstructing past glacial conditions in the Antarctic Peninsula.
The primary data I am working with is vertical crustal rebound data from a continuous GPS site at Palmer Station, located on the western side of the Antarctic Peninsula. The crust of the Earth is rising at a fairly steady rate at this site as part of long term elastic trend derived from the deglaciation of the last Ice Age. As the ice melts over millennia, there is less weight overlying the ground and thus the crust rebounds. Constraining this rate allows us to reconstruct how much ice was present at the site when the ice sheet covering the Antarctic Peninsula was at its maximum extent.
Embedded within the long term signal are smaller scale fluctuations which follow annual cycles, such as the effect of annual snow load on the crust. The measurements from the cGPS stations are precise enough to interpret the position of the crust as it responds to seasonal snowfall and climactic events such as the breakup of the Larsen B ice shelf.
As part of my project, I am comparing the meteorological data and the cGPS data from Palmer Station. By evaluating the time series of snow load at the site against the vertical position of the crust, we can begin to understand the changing mass balance of the ice systems in the region.
How Computers Can Be Programmed to Better Process Natural Language
by Alex Shoulson '10Computer Science Major
Natural (or spoken) languages are very difficult for computers to interpret due to their complexity and ambiguity. So, if you were to enter this English paragraph into a computer program, how could the machine digest the information and answer questions about it?
Additionally, once facts are derived from natural language statements, it is important to not only store them for retrieval, but to enable the computer to perform informed inference. Armed with the two statements "Jim is a fish," and "fish swim," a human user expects the question,"Does Jim swim?" to be trivial.
My thesis explores techniques for solving these problems in the sub-fields of Artificial Intelligence known as Natural Language Processing and Knowledge Representation. This work will continue through the spring, when I aim to program a computer agent that can solve basic math word problems in English such as the following:
"Alice has three apples. Bob has one. Alice gives Bob two apples. Who has more apples?"
Variations in Organic Carbon Concentrations in Oneida Lake
by Stacey Ng '10Geoscience Major
Oneida Lake is the largest lake in New York, and is currently being fed by two major sources in its watershed (Fish Creek and Oneida Creek). Due to recent anthropogenic and agricultural changes in the surrounding area, the lake has experienced alterations that could possibly affect the dynamics of organic carbon concentrations in the lake basin.
The main objective of my senior thesis is to observe how particulate organic carbon concentrations have varied in Oneida Lake within the past century. Through the study of stable carbon isotope ratios, mainly 13C and 12C, we can attempt to determine any overlying trends and sources which are influencing ecological changes in the lake.
Organic carbon values should be expected to vary depending on the type of matter that produced it (e.g. algal matter, agricultural plants such as grasses and corn, or trees and leaf litter). Therefore, by determining the concentrations of 13C at varying depths from a sediment core that was collected, we can propose possible sources for changes in input over time in relation to the history of the lake and its watershed. Knowledge of these trends is important in developing strategies to prevent an overabundance of harmful matter from entering the basin, thus maintaining the health of Oneida Lake.
Eye Tracking as a Measure of Level of ADHD
by Anthony Sali '10Psychology Major
Although the majority of psychological research on ADHD has focused on children, studies with older samples suggest that the cognitive impairments associated with ADHD may continue into adulthood even if the degree of symptomatology lessens. I am currently using eye tracking to examine differences in eye movements between college students who have high ADHD symptomatology and those with low symptomatology on two neuropsychological tasks of cognitive functioning.
The Trail Making test assesses executive functioning and requires participants to switch between numbers and letters as they trace a trail to connect a series of circles in sequential order. Although previous research has shown that adults with ADHD perform more slowly on the Trail Making test than control participants, my study is the first to investigate whether differences in visual scanning are associated with time differences and symptomatology.
I am also using a modified version of Posner's covert orienting paradigm to examine differences in visual processing. With this task I plan to investigate differences that may exist between high and low symptomatology participants in the ability to control saccadic eye movements as well as differences in the latencies of eye movements.
My study of the cognitive functioning of adults with high ADHD symptomatology has important implications for offering improved services to individuals who struggle with ADHD as well as for better understanding the etiology of the disorder.
A Study of Microbial Communities in Green Lake, Fayetteville, New York
by Libby Pendery '10Biology Major
Green Lake, located 40 minutes west of Hamilton College, is one of roughly 800 meromictic lakes in the world. Whereas most lakes experience seasonal turnover of their top and bottom waters, meromictic lakes exhibit two distinct water regions because of a density difference. The monimolimnion, or the bottom water, is too dense to mix with the top water, the mixolimnion, because of a high salinity content.
A third region, termed the chemocline, is the interface between the mixolimnion and the monimolimnion. It serves as a link between physical, chemical and biological properties at different depths throughout the lake. Green Lake offers a unique environment to study bacteria because of its distinct regions (or different environmental conditions) throughout the water column.
My thesis focuses on a molecular, or DNA, analysis of bacterial communities in the lake's water column. I am hoping to determine which types of bacteria are located at the different depths in the lake, and whether individual bacterial communities are specific to one depth or exist in many. For example, the monimolimnion does not contain oxygen, but the mixolimnion does, so bacteria that thrive in the top water could not exist in the bottom water, and vice versa.
When I am able to classify different types of bacteria, my next step is to analyze how they utilize different environmental conditions to generate energy. I will also look at the relationship between bacteria and the lake's geochemistry, or how the pH, temperature and chemical properties in the water affect the existence of bacteria. My research will, hopefully, provide a more comprehensive understanding of Green Lake.