Congratulations Graduate Research Incentive Awardees 2009!
Visitors, please use links provided with each abstract if you want more information about the work described.
| Andrew Michelson |
The salinity of the Caribbean basin controls the strength of ocean circulation in the North Atlantic and thus the distribution of heat throughout the globe. Therefore, in order to understand how ocean circulation changes over short time scales, there is a great need for quantitative climate record from the Caribbean during the late Holocene (approximately the last 4000 years). Modern ostracode species (bivalved microcrustaceans whose calcite shells are preserved in lake sediments) are excellent climate proxies, having been shown to respond to salinity changes in a predictable manner. This project will focus on the creation and testing of a quantitative model to express preserved communities of ostracodes in terms of past climate by identifying climate variables controlling ostracode community assembly today both within individual lakes and across many lakes on the island of San Salvador, Bahamas. |
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| Alyssa Stark |
The gecko’s ability to run along walls and ceilings has recently united the interests of both biologists and materials scientists. Current models of “gecko tape” have replicated the hair-like structures which give the gecko such strong and versatile adhesive capabilities. Although adhesive properties similar to the gecko’s have been replicated by this tape, the implications of patterning along the gecko’s toe pad have yet to be explored. I will test the natural toe pad patterning of different gecko species against an ideal pattern developed using polymer science theories. Although the gecko’s abilities are extraordinary, I expect under unnatural conditions, such as a glass surface, the ideal pattern to have stronger adhesive abilities than the natural patterns of geckos. By investigating gecko toe pad patterning, I will not only advance the design of “gecko tape” but also provide new insight into the development and possible constraints of the gecko’s unique features. |
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| Stephanie Lopez |
Ability of geckos to climb a variety of surfaces has attracted significant attention in recent years. A lot of work has been done to understand the mechanism of gecko adhesion and new materials developed to mimic such properties. Yet another very important aspect governing the gecko’s ability to repeatedly stick and un-stick in a variety of environmental conditions is its ability to keep its feet clean. Liquid coated particles may be a potential hazard to the self-cleaning system if the system is based on van der Waals forces. Looking at an animal based system may show us that geckos will not be able to effectively adhere (generate forces large enough to support the gecko’s body weight) after their setae have been exposed to liquid coated particles. The reduction in adhesion will be do to diminished self-cleaning capacitates. Study of these animals will aid in biologically inspired design surrounding improving gecko inspired robotics as well as developing better self-cleaning surfaces. |
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| Cecilia Boutry |
Spider silk combines high strength and elasticity into a high-performance fiber that scientists seek to replicate in "synthetic silks". However, in web-building spiders, these exceptional qualities vary with spinning conditions, differing in particular between free-ranging spiders and anesthetized, restrained spiders. This suggests spiders have the
ability to control silk properties, potentially through a muscled valve present in the spinning duct of web-building spiders but absent from wandering spiders. Web-building spiders may have evolved novel mechanisms to control silk spinning in part due to the numerous ways in which they utilize silk (in different regions of the web, to adapt to
prey, etc.). This project will compare the variability of silk from web-building spiders and wandering spiders to determine how spiders control silk quality and how this relates to spiders ecology. Understanding these mechanisms will allow scientists to copy them for
synthetic silks.
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| Vassav Sahni |
Cribellum silk thread is found in the aerial capture webs of spiders because this thread helps retain the insects that encounter the web and buys spiders time to subdue them. It is the most primitive type of sticky prey capture thread found in aerial spider webs. It is a composite thread formed of internal supporting fibers covered by a dense mat of several thousand small-diameter fibrils. Fibril, the part of the thread that is responsible for stickiness, is of two types: noded and cylindrical (non-noded). Apart from retaining the insects by snagging onto their setae, this kind of silk has also been found to stick to smooth surfaces like glass and graphite, surfaces of very different chemical compositions. The goal of this project is quantifying the stickiness values and determination of the chemical specie(s) responsible for this stickiness in silk. Understanding this phenomenon would result in the opening up of numerous possibilities for designing adhesives. |
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| Heath Garris |
A key topic in ecology is the spatial organization of diversity. While considerable work has been completed in this area, many questions remain concerning how stream restoration projects affect terrestrial communities. Historically, Bath Creek, a stream that flows through the Bath Nature Preserve, was channelized to claim arable lands for domestic use. Channelization limits flood potential leading to a hypothesized reduction in the breadth of Bath Creek’s riparian zone. This project will evaluate spatial relationships between terrestrial communities associated with Bath Creek and the North Fork of Yellow Creek. I will be performing extensive field sampling and taking aerial images using a blimp-mounted imaging system to generate a Geographic Information System (GIS) for these riparian zones. This GIS will be analyzed to determine the relative impact of Bath Creek’s channelization on associated moth (Lepidoptera) and plant communities and to produce preliminary data for further analysis of Bath Creek’s restoration. |
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| Ashley Wain |
Several studies have shown that Choanoflagellates are a sister group to the metazoans (multicellular organisms). Low levels of oxygen present in the Earth’s atmosphere prior to the transition to multicellularity may have constrained body size and cell number preventing the evolution of multicellularity. Presumably oxygen increases in the Paleozoic environment may have removed that constraint. To test for such an influence of oxygen environment on the evolution of multicellularity I will rear four species of choanoflagellates at both high and low oxygen levels over approximately 800 generations. I will utilize proteomic methods to test for changes in translation associated with multicellularity and elucidate the effects of this environmental change. Utilization of a long term experimental evolutionary approach along with the integration of evolutionary and molecular biology, geology, and paleontology will help uncover the link between protozoa and metazoa. |
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| Andrew Jones |
The introduction and maintenance of sexual reproduction is at the core of evolutionary investigation. Kondrashov’s deterministic mutation hypothesis predicts that the maintenance of sexual reproduction in populations is a direct result of synergistic epistasis between deleterious mutations. Desai et al. suggest that antagonistic epistasis will allow sexual populations to reduce selective load without purging. I will perform a comparative Monte Carlo simulation study of the evolution of sexual reproduction in populations with three types of gene interaction; synergistic, antagonistic, and non-interacting (null model). By allowing accumulation of mutations in the three population types and running thousands of replicate simulations of each type, I will be able to determine which of the two proposed models is more correct. This will be determined by looking for maintenance of sexual reproduction in either the synergistic simulations or the antagonistic simulations. |
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More to come....check back soon for descriptions of more funded projects |
