Tag: Poster 25

Shaping the Face: Genetic Interactions in Zebrafish Jaw Development

Presenter: Braden Larson

Mentor: Charles Kimmel

AM Poster Presentation

Poster 25

Development of the jaw skeleton can be divided into three stages: (1) migration of neural crest cells, precursors of jaw skeletal cells, (2) aggregation of neural crest cells into pharyngeal arches, and (3) differentiation of pharyngeal arch cells into skeletal cells. Signaling between cells is instrumental in all three stages. One signal, Endothelin-1 (edn1), is known to be required for lower jaw development in zebrafish. Work in mice has shown that the signaling molecule Fibroblast growth factor-8 (fgf8) is required for proper edn1 expression, motivating the following hypothesis: edn1 and fgf8a genetically interact in zebrafish jaw development. / We tested this hypothesis by generating fish that carry mutations in both edn1 and fgf8a. These fish are missing cartilage cells from their upper jaw, a phenotype not present in either single mutant. To investigate the cause of this phenotype we examined cells of the pharyngeal arches. We found that the first arch, which is the precursor to the lower and upper jaw, to be dysmorphic. We then examined neural crest cell migration. While migration appeared normal, neural crest cells failed to aggregate into the intermediate region of the first arch in double mutant fish, placing the manifestation of the double mutant phenotype in stage two of jaw skeleton development. Our findings suggest a novel genetic interaction or synergy between edn1 and fgf8a in which they function to promote aggregation of neural crest cells into the intermediate region of the first pharyngeal arch.

Biomechanics of Jellyfish in Turbulence

Presenter : Susan Brush

Mentor : Kelly Sutherland

Major : Marine Biology

Poster 25

Hydromedusan jellyfish are planktonic organisms and, as such, are exposed to ocean water motion that directly impacts how they eat, disperse and eventually spawn. To understand the effect that realistic levels of water motion has on individual organisms, our research examines the role that turbulence plays in the swimming behavior of hydromedusae. Using a laboratory turbulence tank, we observed the behavior of two species of hydromedusae with distinct body shapes at two levels of turbulence. We were able to establish that these two species occupy different depths within the water. While statistical comparison resulted in no significant dif- ference in swimming speed and acceleration between turbulence treatments, qualitative comparisons between swimming patterns of the two species suggests that turbulence does influence the swimming trajectories of prolate individuals (bullet-shaped) com- pared oblate individuals (plate-shape). Swimming behavior is closely tied with feeding behavior in hydromedusae. Therefore these findings indicate that turbulent conditions, which are ubiquitous in the ocean, may disproportionately influence feeding in certain species and could impact the overall success of these organisms.

Attentional and Neuropsychological Assessments Following Concussion in Adolescents and Young Adults

Presenter: Madison Murray

Mentor: Li-Shan Chou

Poster: 25

Major: Biology

Executive function has been defined as utilizing external stimuli to plan purposeful action and may be a sensitive way to detect concussion-related deficits. The adolescent brain has not reached full maturation and is undergoing rapid development of executive functions, so this age group may be affected by head trauma more than young adults. It was hypothesized that adolescents with concussion would perform worse on executive function tasks than young adults with concussion in relation to matched control groups. Two executive function tests, (Attentional Network Test and Task Switching Test) and one neuropsychological test (ImPACT), were each administered to 44 subjects who sustained a concussion (24 adolescents, 20 young adults) and 44 healthy control subjects matched by sex, height, and weight (24, adolescents, 20 young adults). Tests were administered within 72 hours of injury, and again at 1 week, 2 weeks, 1 month, and 2 months post-injury. Results indicated that conflict resolution ability deficits persisted in the adolescent group compared to their controls throughout the two months of testing (p=0.043). Such differences were not detected between young adult concussion and control groups. Differences between adolescent concussion and control groups on ImPACT variables were detected up to one-month post injury (p<0.05), but not between young adult concussion and control groups. Based on the results, adolescents appear to display greater deficits throughout the two months post-injury than young adults in relation to a control group on measures of attentional and neuropsychological function.

Comparison of Measures of Inter-individual Affiliation among Ring-Tailed Lemurs (Lemur catta)

Presenter: Leslie Gotuaco

Mentors: Stephen Frost and Frances White, Anthropology

Poster: 25

Major: Environmental Science 

Primatologists use a number of behavioral measures to assess patterns of affiliation and aggressions in groups of primates. These patterns can, however, vary greatly within a species with behavioral context. Lemurs, for example, are well known for the importance of context in the variation of aggression in feeding and non-feeding contexts as seen in both female dominance and female feeding priority. This study examined whether there are also variations in affiliation between feeding and non-feeding contexts. One of these measures, grooming, is widely accepted as a mechanism for social bonding, but it is not an appropriate measure for affiliation during feeding. We therefore used co-feeding as a measure of affiliation during feeding. We then used a non-parametric multivariate statistical comparison to see if the patterns of affiliation are consistent between these two contexts. We studied a group of semi-free-ranging ring-tailed lemurs on St. Catherine’s Island, Georgia and collected 188 hours of behavioral data. Observations used focal animal sampling and all occurrence sampling of social behavior. We calculated indices for grooming and co-feeding for all possible pairs of individuals. A Mantel test was used to determine the correlation between the two affiliative measures. We found a significant correlation between our measures (r = 0.7509, t = 8.635, p < 0.0001). These results demonstrate that affiliation patterns seen in non-feeding contexts are consistent with affiliation during feeding.

Gradient Estimation Algorithm for the ATLAS Level-1 Calorimeter Trigger Upgrades

Presenter: Luc Lisi

Faculty Mentor: Stephanie Majewski

Presentation Type: Poster 25

Primary Research Area: Science

Major: Physics

The Large Hadron Collider (LHC) is a proton-proton particle collider that at the present (2016) is the most powerful particle accelerator in the world. At peak operation, there can be as many as 600 million proton-proton collisions
per second and as a result, deciding which events are useful to analysis and which events are not, in real time, is paramount to data collection. To accomplish this, accurate calorimeter object reconstruction and suppression of multiple interactions per bunch crossing (pileup) in the ATLAS detector at the Large Hadron Collider plays a key role in triggering on important proton-proton collision events. In particular, we aim to improve the performance of the jet and missing transverse energy triggers. We present simulation studies of a novel algorithm for the Level-1 Calorimeter trigger in the Phase-I and Phase-II upgrades of the trigger electronics that aims to improve this trigger efficiency. Inspired by image processing techniques, we use gradient estimation to extract areas of topological interest in the 0.2×0.2 (in eta-phi) towers of the global feature extractor (gFEX), a component of the Level-1 trigger system for the Phase-I upgrade. Our preliminary results have found that these techniques are capable of suppressing pileup and reconstructing calorimeter objects in simulated events. However, further studies must be conducted to understand the algorithm’s speed, efficiency, and other factors critical to implementation in the final trigger.

Implementation of Artificial Intelligence in Motor Learning

Presenter(s): Sydney Bright − Human Physiology

Faculty Mentor(s): Mike Hahn

Poster 25

Research Area: Human Physiology

Motor control of the forearm flexors and extensors can be impaired due to trauma, such as a stroke, which can hinder the ability to perform daily tasks. In this study, the effects of an Artificial Intelligence (AI) controller on the ability of healthy subjects to learn a novel computer game control task were examined. By using the electromyography sensors of a Myoband in tandem with a Scratch program of Flappy bird, a program was created that adapts to player specific skills. Purpose: The purpose of this experiment was to determine the motor learning outcomes given an adaptive AI motor learning environment. Hypothesis: It was hypothesized that an adaptive AI will result in less motor learning. Methods: Subjects played a modified Flappy Bird game with a multi-channel EMG sensor that fits around the forearm (Myoband). The experiment requires two consecutive days of participation. During the first day, subjects had a 2-minute warm up period followed by 20 rounds of playing the game. The second day consisted of a similar 2-minute warm up period followed by 3 rounds of the game. Results: 46 of 48 subjects have been recorded. So far, the AI group has an average 17 point improvement, linear group has 31 points and the random group has 33 point improvement. Discussion: No statistical test have been done, but from preliminary analysis of the data, the hypothesis seems to be supported.

A Flux Story: Harnessing the Power of a Continuous Growth Synthesis to Study the Formation of Indium Oxide Nanocrystals

Presenter(s): Makenna Pennel

Faculty Mentor(s): Jim Hutchison & Kenyon Plummer

Poster 25

 Session: Sciences

Nanoparticles have led to incredible technological advances and continue to revolutionize the world around us. In order to pursue novel forms and enhanced synthetic control of these particles, however, we need a fundamental understanding of the growth processes involved. The concept of flux— in this context, the rate at which new material (monomer) adds to a growing particle— is one factor that has remained elusive with traditional synthetic routes. Using a novel slow-injection, continuous growth method developed by the Hutchison lab, we were able to study flux and its influence on the morphology (appearance) of indium oxide nanocrystals, as visualized with transmission electron microscopy. It was found that high flux conditions resulted in relatively branched particle morphologies, while relatively lower flux resulted in cubic particles. We tested several growth mechanisms to explain these observations in the context of different temperatures, and from these experiments, developed a model for nanocrystal growth involving diffusion of monomer across the crystal surface and attachment at reactive edge sites. Our group then utilized this model and the principles of flux to alter the morphology of preexisting particles. The importance of flux during nanoparticle growth, as demonstrated in this study, has far-reaching synthetic implications and should be a consideration in future inquiries.