2008 Summer Undergraduate Research and Creative Achievements Forum (MU)
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The MU Summer Undergraduate Research and Creative Achievements Forum showcases the creative and scholarly activities that undergraduates have been engaged in over the summer. All students engaged in scholarly or creative activity with a faculty mentor are invited to present their work.
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Item Synthesis and characterization of amorphous astrominerals(University of Missouri--Columbia. Office of Undergraduate Research, 2008) Zullig, Bryson; Whittington, Alan G.; Speck, Angela K.; University of Missouri-Columbia. Office of Undergraduate Research; Undergraduate Research and Creative Achievements Forum (2008 : University of Missouri--Columbia)Asymptotic Giant Branch (AGB) stars are the main contributors of solid material (dust) to the interstellar medium. The dust forms as gas escaping from the star cools and condenses to form a circumstellar dust shell. Around oxygen-rich stars, most of the dust particles are silicates, but important questions remain about which minerals are formed and whether the grains are crystalline or amorphous (glassy). Dust grains that form below the glass transition temperature (Tg) of a particular mineral should be amorphous, while those that form much above Tg should be crystalline. The most refractory silicates predicted to form are members of the Melilite group of minerals, whose end-members are Gehlenite (Ca2Al2SiO7), Sodium Melilite (CaNaAlSi2O7) and Åkermanite (Ca2MgSiO7). Synthetic glasses corresponding to these end-member compositions were synthesized from oxide and carbonate powders by melting in Pt crucibles in a muffle furnace at temperatures up to 1650˚C. The viscosity of the melts was measured by the parallel-plate technique in the temperature range 655 to 900˚C, over the viscosity range 2x107 to 91012 Pa s. The viscosity-temperature data were interpolated to determine Tg for each glass, taken to be the temperature at which the viscosity is 1012 Pa s. Two naturally occurring mineral samples, of åkermanite and gehlenite, were also melted. At higher temperatures and lower viscosities than about 108 Pa s, crystallization is expected to be rapid relative to the timescale of cooling in circumstellar dust shells. Our experimentally determined glass transition temperatures therefore provide constraints on the nature (crystalline vs amorphous) of several refractory astrominerals predicted to be found in these shells. Future studies of these glasses will include infrared spectroscopy, in order to better interpret astronomical spectra and test for the presence of amorphous dust with these compositions. The results will be used to test competing models for circumstellar dust formation.Item Turnover of neotropical migrant birds in eleven year old clear cuts during July(University of Missouri--Columbia. Office of Undergraduate Research, 2008) Zenzal, Theodore; Burke, Alicia D.; Porneluzi, Paul; University of Missouri-Columbia. Office of Undergraduate Research; Undergraduate Research and Creative Achievements Forum (2008 : University of Missouri--Columbia)Capture and release of birds via mist net and banding techniques has proven to be one of the best way to census turnover or persistence of birds during migration, breeding, and post-breeding seasons. Our study looked at recapture rates in neotropical migrant birds using mist net and banding techniques on the edge of an eleven year old clear cut as part of the Missouri Ozark Forest Ecosystem Project. Our study took place during the month of July which is considered post breeding season. The initial data for this study was taken at the beginning of July and the follow up data was taken at the end of July. The purpose was to see if birds banded during the first part of July would persist in these same territories or if the majority of birds captured would be new captures. If the latter is the outcome then it is to be assumed that most birds in the post-breeding season are not keeping territories. We believe that we will have increased rates of new captures over recaptured birds. Most of the individuals being captured are hatch year birds considered to be both early succession and mature forest species. This could mean that they are using the clear cuts for several reasons; including abundant resources, less predation, or dispersal.Item Reactivity of Germanium (100)-2x1 with diethyl ether(University of Missouri--Columbia. Office of Undergraduate Research, 2008) Zahra, Jimmy; Greenlief, Michael; University of Missouri-Columbia. Office of Undergraduate Research; Undergraduate Research and Creative Achievements Forum (2008 : University of Missouri--Columbia)There is a great interest in the development of new devices for the microelectronics industry. Changes in materials are continually tried to obtain better performance and higher speed devices. Germanium (Ge), in its natural state, is one of the semiconductors that seems to offer such characteristics for future generation devices. Nevertheless, one of the factors that do not allow us to use it adequately is its interface instability with other components. Here we examine the reactivity of diethyl ether (C4H10O) on Ge with the purpose of controlling the germanium interface. The reactions are investigated with Auger Electron Spectroscopy (AES) and Ultra-Violet Photo-electron Spectroscopy (UPS). The Ge(100)-2x1 dimer surface is prepared by first thermally removing the native oxide-terminated surface at temperatures greater than ~870K. Surface pretreatment includes extensive degassing at high temperatures and argon ion (Ar+) sputtering at room temperature, under ultra-high vacuum (UHV) conditions. Controlled exposures of diethyl ether to the Ge surface are done with a variable leak valve connected to a stainless steel tube doser. The thermal stability of C4H10O on the germanium surface is examined, as well as, its coverage dependence. The solid state spectrum of diethyl ether will be compared with its gas phase spectrum and the molecular orbital energies calculated by density functional theory (DFT). The thermal behavior of diethyl ether with germanium will be monitored by UPS and compared with possible calculated intermediates. The results of these studies will provide the foundation for a more detailed photoelectron spectroscopy and temperature programmed desorption investigation.Item Influence of miRNA on brace root patterning in Zea mays L.(University of Missouri--Columbia. Office of Undergraduate Research, 2008) Young, Marie; Gerau, Michael; Ware, D.; Davis, Georgia L.; University of Missouri-Columbia. Office of Undergraduate Research; Undergraduate Research and Creative Achievements Forum (2008 : University of Missouri--Columbia)Brace roots reduce lodging by providing support and represent the majority of the root system in adult plants. Previous quantitative trait locus mapping results showed that Teopod1 (Tp1), Teopod2 (Tp2), and Corngrass1 (Cg1), all mapped in chromosome regions which influence brace root patterning. Tp1 and Tp2 are semi-dominant mutants and Cg1 is a dominant mutant that result in delayed-phase-change and overlap between the juvenile and reproductive phases. Gibberellic acid (GA) promotes phase change and exogenous GA alters Tp1 and Tp2 phenotype . Prior analysis of GA mutants in our laboratory and others indicates that GA affects brace root patterning. We performed a means comparison between Tp1 and Tp2 and their wild-type siblings and identified significant differences in brace roots traits, specifically, mutants exhibited more nodes with brace roots and more brace roots at a node than their wild-type counterparts. Cg1 encode a member of the miR156 family which is known to target squamosa promoter-binding (SPB)-like proteins. Tp1 and Tp2 have also been suggested to encode members of the miR156 family. To further validate the role of miRNA156 in brace root patterning, we performed association analysis with available sequence from the parents of the nested association mapping (NAM) population and brace root trait data. Preliminary analysis supports the involvement of miRNA156 family members in brace root patterning. Additional sequencing of miRNA156 in a larger group of maize lines is underway to provide a more robust dataset for association analysis.Item Wading in the gene pool: Female preference for long mating calls in gray tree frogs (Hyla versicolor)(University of Missouri--Columbia. Office of Undergraduate Research, 2008) Yi, Si Yol; Welch, Allison; Gerhardt, H. Carl; University of Missouri-Columbia. Office of Undergraduate Research; Undergraduate Research and Creative Achievements Forum (2008 : University of Missouri--Columbia)Female gray tree frogs (Hyla versicolor) exhibit a clear preference for long mating calls. Moreover, the expression of this preference varies. The "good genes" model of sexual selection suggests that this is because females with extreme preferences mate with males with the most exaggerated traits, so their offspring will carry the genes for the extreme values of both trait and preference. Another possible explanation for variation in preference is that females in good physical condition, measured as body mass relative to length, will be better able to travel longer distances to find a longer calling male, resulting in a stronger call preference. We assessed the preference strength of lab-reared female frogs that are the offspring of short and long-calling fathers. We manipulated the condition of these females by placing them on a high and low feeding treatment. Frogs were tested in a soundproof acoustic testing chamber to determine preference strength, which was measured by using unequal playback levels of synthetic mating calls. We defined preference strength as the amount that the intensity of a long call can be reduced relative to the short call before the female prefers the shorter call. We found that preference strength was not significantly affected by father's call length, family, food treatment, or mass. Additionally, the response time for testing showed no relationship with either preference strength or mass. While there were no trends in the data, our sample size was small. Further testing with a larger sample size will give us a better idea of whether or not preference strength is affected by male call length or condition. Alternatively, female preference might be linked to variables we did not measure, such as age or past experience.