Molecular evidence of Late Archean archaea and the presence of a subsurface hydrothermal biosphere

Author Posting. © National Academy of Sciences of the USA, 2007. This is the author's version of the work. It is posted here by permission of National Academy of Sciences of the USA for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 104 (2007): 14260-14265, doi:10.1073/pnas.0610903104.Highly cracked and isomerized archaeal lipids and bacterial lipids, structurally changed by thermal stress, are present in solvent extracts of 2,707-2,685 million year old (Ma) metasedimentary rocks from Timmins, Ontario, Canada. These lipids appear in conventional gas chromatograms as unresolved complex mixtures (UCMs) and include cyclic and acyclic biphytanes, C36-C39 derivatives of the biphytanes, and C31-C35 extended hopanes. Biphytane and extended hopanes are also found in high pressure catalytic hydrogenation (HPCH) products released from solvent-extracted sediments,indicating that archaea and bacteria were present in Late Archean sedimentary environments. Post-depositional, hydrothermal gold mineralization and graphite precipitation occurred prior to metamorphism (~2,665 Ma). Late Archean metamorphism significantly reduced the kerogen’s adsorptive capacity and severely restricted sediment porosity, limiting the potential for post-Archean additions of organic matter to the samples. Argillites exposed to hydrothermal gold mineralization have disproportionately high concentrations of extractable archaeal and bacterial lipids relative to what is releasable from their respective HPCH product and what is observed for argillites deposited away from these hydrothermal settings. The addition of these lipids to the sediments likely results from a Late Archean subsurface hydrothermal biosphere of archaea and bacteria.This project was supported by NASA Exobiology grant #NAG5-13446 to Fabien Kenig. SEM analysis was supported by NSF grant EAR 0318769 to Juergen Schieber. GC×GC analysis was supported by NSF grant IIS-0430835 and the Seaver Foundation to Christopher M. Reddy

Evaluation of medical isotope production with the accelerator production of tritium (APT) facility

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Decision making and strategic planning for disaster preparedness with a multi-criteria-analysis decision support system

In the context of the CRISMA FP7 project we have developed a seamless decision support concept to connect simulated crisis scenarios and aggregated performance indicators of impact scenarios with state of the art Multi- Criteria Decision Analysis (MCDA) methods. To prove the practicality of the approach we have developed a decision support tool realising the important aspects of the method. The tool is a highly interactive and user-friendly decision support system (DSS) that effectively helps the decision maker and strategic planner to perform multi-criteria ranking of scenarios. The tool is based on state-of-the-art web technologies

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