17th Denman Undergraduate Research Forum (2012)

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    A Sociophonetic Study of the French [R]: Socioeconomic Factors Reflected in Linguistic Variation
    (2012-05-09) Little, Sarah; Campos-Astorkiza, Rebeka
    /R/ sounds display much variation in many of the world’s languages, being vulnerable to changes in their pronunciation. This unstable type of sound is found in French. Many linguists have studied the /R/ sound variation of different dialects around the Francophone world, such as French-speaking Africa or Canadian French. However, the variation found within France has not been thoroughly investigated. I initiated this research with the aim to further our understanding of the linguistic evolution of speakers living in France. This project seeks to prove that differences in /R/ pronunciation can be attributed to various social factors, such as gender, age, and contact with other languages, as well as linguistic factors such as stress and surrounding sounds. This study analyzes the speech of Paris-native speakers or those who have lived in the city for an extended period of time. For this purpose, I recorded these speakers performing three tasks: reading a list of words, which they had to put into sentences; a picture description; and an informal interview. After having analyzed most of the data, I have found that the speakers who have contact with other languages (specifically African creoles) show cases of pronouncing the /R/ similar to a vowel and have cases of trills (the Old French pronunciation), which are not found in the other speakers. In addition, the younger speakers show signs of exposure to a more recent phenomenon: a weakening of the sound. These results suggest that the behavior of French speakers in France is different from other dialects since they display an evolution in their language in which the French /R/ is shifting to a completely different sound. These findings shed light on the origin of language changes in Standard French, Paris, and help us predict when French speakers can expect an upcoming linguistic phenomenon.
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    Investigating Long-Term Diet and Marine Resource Use in Kohala, Hawaiʻi
    (2012-05-09) Lipphardt, Jacqueline; Field, Julie
    Marine animals, including fish, mollusk, octopus and squid, were key components of the Hawaiian diet in prehistory. The goal of my research project is to examine long-term prehistoric gathering strategies and to determine if resource depression of mollusk populations in prehistory. I am currently investigating mollusk use in prehistory by analyzing remains from archaeological household sites in Kohala, Hawaiʻi. I am looking at the distribution of different species of mollusk remains throughout Kohala, and analyzing the changes through time. This project is ongoing, but so far I have found no significant changes in species consumed that indicate resource depression. The species and amount of mollusk consumed through time varies within regions in Kohala, but does not indicate a negative human impact on marine resources through time.
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    Antipsychotic Drug Impact on Dopaminergic Neurons
    (2012-05-09) Klausing, Alex; Wallace, Lane
    Antipsychotics are used to treat people diagnosed with schizophrenia by blocking dopamine receptors, specifically the D2 subtype. These drugs all increase dopamine in the extracellular to a similar extent by increasing firing rate and synthesis of new dopamine. However, the drugs vary on the rate of synthesis and the amount of dopamine’s metabolite, DOPAC. Previous research has shown this might be due to the difference of antipsychotic drugs’ affinity to the D2 autoreceptor. The purpose of this study is to explain the variability of antipsychotic drugs on the differences in DOPAC levels and dopamine synthesis rates. The way chosen to study this is through a computational model that records the amount of dopamine and DOPAC molecules in certain compartments of a neuron over a certain time. This model includes all known mechanisms and pathways in which dopamine and DOPAC can be created, transported, and metabolized. By studying the changes in levels of dopamine and DOPAC and the pathways involved, one can make conclusions about the area(s) that a drug acting on a dopaminergic neuron effects. When using antipsychotic drugs, the model showed that there was a difference between the leak of dopamine molecules out the vesicles into the cytosol depending on the drug used. The greater the ability the drug had to penetrate the membrane of the neuron and eventually vesicular membrane, the greater the amount of dopamine leaked out of the vesicle. The higher leak value directly correlated to higher cytosolic DOPAC levels and dopamine synthesis rates of the cytosolic pathway. These results explain another possible mechanism of the drug that controls synthesis rates besides D2 receptor activity.
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    Early Developmental Ethanol Exposure Disrupts Hippocampal-Dependent Learning via Deregulated NMDA Receptor Function in a Rodent Model of Fetal Alcohol Syndrome
    (2012-05-09) Coppola, Jennifer; Lindquist, Derick
    Consuming alcohol during pregnancy may lead to a range of lifelong disorders in the resulting offspring known as fetal alcohol spectrum disorders (FASD). The physical and mental impairments are dependent on the developmental timing and resulting blood alcohol concentration. A fetal alcohol syndrome (FAS) rodent model in which a milk/ethanol solution is administered to rat pups across postnatal days (PD) 4-9—a period commensurate to the third trimester in human pregnancy—yields results similar to those seen in individuals with FASD. Behavioral tests given to adult rats are used to assess alcohol’s neurotoxic effects on the developing hippocampus. The context pre-exposure facilitation effect (CPFE) is a form of Pavlovian conditioning in which rats associate a particular context with a footshock. This three-phase task is designed to detect even subtle impairments of hippocampal function following early ethanol exposure, as measured by reduced context-mediated freezing compared to control rats. Alcohol is known to alter NMDA receptor (NMDAR) composition and function across development, a factor that potentially contributes to the deficient learning observed in FAS rats. To investigate this hypothesis, we examine the expression of Arc, an effector immediate early gene (IEG) that is activated downstream of the NMDAR and known to be involved in associative synaptic plasticity and learning. We predict that ethanol-induced NMDAR hypofunction will be detectable by decreased Arc expression in the dorsal and/or ventral sub-region(s) of the hippocampus. Preliminary results indicate administration of an NMDAR partial agonist, D-cycloserine (DCS), prior to initial context exposure facilitates learning in FAS rats, as evidenced by enhanced freezing. Taken together, the data suggest that early developmental ethanol exposure may disrupt NDMAR function, which persists through adulthood, and that pharmacological NMDAR modulation could potentially ameliorate these deficits.
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    Asynchronous Stimulation for Cochlear Implants
    (2012-05-09) Zajdel, Tom; Kwon, Bomjun; Bibyk, Steven
    This work contributes the first psychoacoustic tests of Asynchronous Interleaved Sampling (AIS) performed with commercially available implants. AIS was originally proposed as an alternative to Continuous Interleaved Sampling (CIS) to demonstrate the benefit of asynchronous stimulation on conveying phase information. AIS automatically adjusts each channel's stimulation rate based on its relative temporal importance, mimicking the behavior of neurons. However, the algorithm was never tested with actual CI patients, so its claim of improving phase perception has stood unsubstantiated. The software design and implementation of AIS lays the groundwork for the first qualitative tests of the method's effect on phase discrimination. CI users participated in Schroeder phase discrimination (SPD) experiments to evaluate AIS's presentation of phase and temporal information. AIS performs comparably to CIS in SPD and in some cases introduces a new intelligible temporal cue. The results suggest that consideration of other factors such as electrode spacing and parameter adjustment may have the potential to improve the performance of asynchronous stimulation algorithms in CI devices. Asynchronous stimulation may also be applied to other technology, and represents a subject with rich synergy between engineering and biology.