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Full-Text Articles in Physical Sciences and Mathematics
Glacial Origin Of Massie Creek Gorge, Greene County Ohio, Dylan J. Mckevitt
Glacial Origin Of Massie Creek Gorge, Greene County Ohio, Dylan J. Mckevitt
The Research and Scholarship Symposium (2013-2019)
Massie Creek Gorge is one of several small but impressive canyons in Greene County, Ohio that cut through a typically low-relief landscape. It displays spectacular dolomite cliffs (up to 20 m high), large rockfalls (up to 1800 m3), numerous large potholes (up to >5 m wide and >7 m high), a dry valley branching off the main channel with a resultant bedrock island (≈30,000 m2 in area) and two boulder bars on its lee side (the largest ≈13.5 m thick). Short, dry side canyons are cut to the same depth as the main drainage and sometimes contain …
Martian Life Detection With Amino Acid Enantiomers, Ali Jamil, Gaosen Zhang, Henry J. Sun
Martian Life Detection With Amino Acid Enantiomers, Ali Jamil, Gaosen Zhang, Henry J. Sun
Undergraduate Research Opportunities Program (UROP)
The Viking mission showed that Martian soil can degrade a heterotrophic medium to carbon dioxide as if live microorganisms were present. The result is considered inconclusive, however, because abiotic oxidants, such as superoxides, may also exist on Mars and would explain the Viking result. One way to resolve this ambiguity is to repeat the Viking experiment with a isomerically pure medium. The consumption of one isomer, either D or L, would indicate biological activity. Indiscriminate destruction of both isomers would indicate abiotic redox processes. This idea was validated for glucose by REU research last summer (Sun et al. 2009). The …
Martian Life Detection With Xylose Enantiomers, Arturo White, Gaosun Zhang, Henry J. Sun
Martian Life Detection With Xylose Enantiomers, Arturo White, Gaosun Zhang, Henry J. Sun
Undergraduate Research Opportunities Program (UROP)
Ability of Martian soil to degrade carbohydrates, shown by the Viking mission, has two interpretations. One possibility is that the soil harbors living microorganisms. Alternatively, the soil is sterile but chemically oxidizing, i.e. it is laden with photochemical oxidants. It was shown by REU research last summer that these two possibilities can be distinguished by the use of glucose enantiomers. Life is selective: Earth organisms use D-glucose, but ignore Lglucose. This stereo selectivity is absent in chemical reactions. The goal of this project is to test if xylose, a five carbon sugar, is also suitable for chiral life detection. Mixed …
Stereospecificity In Glucose Consumption: A New Approach To Martian Life Detection, Vienna R. Saccomanno, Henry J. Sun
Stereospecificity In Glucose Consumption: A New Approach To Martian Life Detection, Vienna R. Saccomanno, Henry J. Sun
Undergraduate Research Opportunities Program (UROP)
In 1976, the Viking mission made a remarkable discovery: Martian soil was capable of decomposing an organic nutrient broth to carbon dioxide as if it contained live microorganisms. However, a biological interpretation of this finding is in apparent contradiction with the gas chromatograph-mass spectrometer aboard the Viking landers, which showed Martian soil to be devoid of indigenous organics. To reconcile these findings, it has been hypothesized that unknown abiotic oxidants, such as peroxide and superoxide, are present on Mars and that they were responsible for its soil reactivity. The objective of this research is to develop a life detection method …