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Radiation Physics and Chemistry
A quantitative model of water radiolysis and chemical production rates near radionuclide-containing solids
Mary Dzaugis*, Arthur J. Spivack, Steven D’Hondt*
*C-DEBI Contribution 270
We present a mathematical model that quantifies the rate of water radiolysis near radionuclide-containing solids. Our model incorporates the radioactivity of the solid along with the energies and attenuation properties for alpha (α), beta (β), and gamma (γ) radiation to calculate volume normalized dose rate profiles. In the model, these dose rate profiles are then used to calculate radiolytic hydrogen (H2) and hydrogen peroxide (H2O2) production rates as a function of distance from the solid-water interface. It expands on previous water radiolysis models by incorporating planar or cylindrical solid-water interfaces and by explicitly including γ radiation in dose rate calculations. To illustrate our model’s utility, we quantify radiolytic H2 and H2O2 production rates surrounding spent nuclear fuel under different conditions (at 20 years and 1000 years of storage, as well as before and after barrier failure). These examples demonstrate the extent to which α, β and γ radiation contributes to total absorbed dose rate and radiolytic production rates. The different cases also illustrate how H2 and H2O2 yields depend on initial composition, shielding and age of the solid. In this way, the examples demonstrate the importance of including all three types of radiation in a general model of total radiolytic production rates.
The FASEB Journal
New aminopeptidase from “microbial dark matter” archaeon
Karolina Michalska, Andrew D. Steen*, Gekleng Chhor, Michael Endres, Austen T. Webber, Jordan Bird, Karen G. Lloyd*, Andrzej Joachimiak
*C-DEBI Contribution 268
Marine sediments host a large population of diverse, heterotrophic, uncultured microorganisms with unknown physiologies that control carbon flow through organic matter decomposition. Recently, single-cell genomics uncovered new key players in these processes, such as the miscellaneous crenarchaeotal group. These widespread archaea encode putative intra- and extracellular proteases for the degradation of detrital proteins present in sediments. Here, we show that one of these enzymes is a self-compartmentalizing tetrameric aminopeptidase with a preference for cysteine and hydrophobic residues at the N terminus of the hydrolyzed peptide. The ability to perform detailed characterizations of enzymes from native subsurface microorganisms, without requiring that those organisms first be grown in pure culture, holds great promise for understanding key carbon transformations in the environment as well as identifying new enzymes for biomedical and biotechnological applications.
Meetings, Workshops and Activities
Time: September 8-10, 2015
Location: Buenos Aires, Argentina
Application: The workshop is open to U.S. and international participants, and the deadline to apply is June 19, 2015. Students and early career researchers are encouraged to apply. Limited travel support is available for U.S. scientists. Submit a Workshop Proposal
The U.S. Science Support Program, associated with the International Ocean Discovery Program, is currently accepting workshop proposals. The submission deadline is June 19, 2015. Proposed workshops should promote the development of new ideas to study the Earth’s processes and history via scientific ocean drilling. Funding may be requested for small meetings or to support participants at larger international workshops. Meetings and workshops may focus on a scientific drilling theme or topic, or they may focus on a geographic region, integrating multiple topics. Broad-based scientific community involvement, co-sponsorship by related programs, and the active participation of graduate students and early career scientists are strongly encouraged.
IODP: Apply to Sail on Expedition 363 Western Pacific Warm Pool and Expedition 366 Mariana Convergent Margin
Western Pacific Warm Pool (30 September – 30 November 2016) aims to understand the interaction between climate and the Western Pacific Warm Pool (WPWP) from the middle Miocene to Holocene. A series of sites will be drilled in the western equatorial Pacific and eastern Indian Ocean to investigate: the role and response of the WPWP to millennial climate variability during the late Quaternary, changes in the WPWP and relation to monsoon activity on orbital timescales during the Pliocene-Pleistocene, changes in the Indonesian Throughflow during the Pliocene-Pleistocene, and the long-term evolution of WPWP sea surface and intermediate water temperatures and water chemistry since the middle Miocene. Mariana Convergent Margin (30 November 2016 – January 2017) will investigate geochemical, tectonic, and biological processes at intermediate depths of an active subduction zone. This expedition will core the summits and flanks of serpentinite mud volcanoes on the forearc of the Mariana system, a non-accretionary convergent plate margin in the western Pacific. In addition, a reentry cone and casing system will be installed at three sites to provide the infrastructure for post-cruise installation of long-term monitoring systems and the existing Hole 1200C borehole observatory (CORK) will also be removed. Applications: opportunities exist for researchers, including graduate students, in all specialties, including sedimentologists, structural geologists, paleontologists, biostratigraphers, petrologists, paleomagnetists, petrophysicists, borehole geophysicists, microbiologists, and inorganic/organic geochemists. U.S.-affiliated scientists interested in participating in these expeditions should apply to sail through the U.S. Science Support Program, by visiting http://usoceandiscovery.org/expeditions. The deadline to apply is August 15, 2015.
NSF: Faculty Early Career Development Program (CAREER)
See also the FAQ. Full proposal deadlines: July 21-23, 2015.
Simons Foundation, Howard Hughes Medical Institute and Bill & Melinda Gates Foundation: 2016 Faculty Scholars Competition
Application deadline: July 28, 2015.
National Academies: Research Associateships for Graduate, Postdoctoral and Senior Researchers
There are four annual review cycles and the next closes August 01, 2015.
NSF: Earth Sciences Postdoctoral Fellowships (EAR-PF)
Full proposal deadline: January 12, 2016
NSF: Geobiology and Low-Temperature Geochemistry Program Solicitation
Proposals accepted anytime.
IODP-USSSP: Proposals for Pre-Drilling Activities and Workshops
The U.S. Science Support Program (USSSP) accepts proposals on a rolling basis for pre-drilling activities and semi-annually for workshops, related to the International Ocean Discovery Program (IODP).
IODP/Texas A&M: Assistant Research Scientist – Expedition Project Manager/Staff Scientist – Borehole Geophysics
The International Ocean Discovery Program (IODP) at Texas A&M University invites applications for an Assistant Research Scientist (Expedition Project Manager/Staff Scientist) with expertise in any aspect of borehole geophysics, petrophysics, or geophysics. A Ph.D. in geosciences or related field, and demonstrated on-going research experience is required. Applicants must have a demonstrated fluency in written and spoken English. Experience as a seagoing scientist, especially in scientific ocean drilling, is preferred. This position will serve as the Expedition Project Manager to coordinate all aspects of precruise expedition planning, sea-going implementation, and postcruise activities. These duties include sailing as the IODP scientific representative on a two-month IODP expedition approximately once every 1 to 2 years. Individual scientific research, as well as collaboration with colleagues at Texas A&M University in fulfilling its educational mission, is required. This position will also provide scientific advice on laboratory developments in their area of specialization including scientific implementation of downhole logging on the JOIDES Resolution. This is a regular full time position, contingent upon continuing availability of funds for IODP. We will begin reviewing applications on September 15, 2015, but will continue to accept applications until candidates are selected for interviews.
IODP-USSSP: Open Call for USAC Chair
The U.S. Science Support Program (USSSP), in association with the International Ocean Discovery Program (IODP), is seeking a new Chair of the U.S. Advisory Committee for Scientific Ocean Drilling (USAC). The Chair will collaborate with current members of the USAC and serve a two-year term beginning on October 1, 2015. Salary support for the equivalent of four months per year will by provided by USSSP. USAC advocates on behalf of, and provides a broad range of services to, the U.S. scientific ocean drilling community in order to enhance U.S. participation in all aspects of IODP. It also provides advice and assistance to USSSP in carrying out the USSSP Annual Program Plan, by contributing input on IODP expedition scientific party and panel nominations; USSSP workshop and pre-drilling proposal reviews; the formulation of an effective education and outreach plan; and other critical activities. The full Terms of Reference for USAC can be found at http://usoceandiscovery.org/terms-of-reference/. Scientists interested in this opportunity should send a cover letter and a two-page CV to firstname.lastname@example.org by July 15, 2015. Letters should briefly document any previous committee experience, and describe your interest in scientific ocean drilling and the activities of the USAC panel. Letters will be evaluated by a panel composed of the USSSP principal investigators and several past USAC chairs. Questions should be directed to Carl Brenner at email@example.com.
Rice University: Faculty Postition in Earth and Planetary Science
We seek creative and promising candidates across the broad spectrum of earth and planetary science who complement the disciplines represented in our department. Successful candidates are expected to direct an active research program, supervise graduate research, and teach courses for undergraduate and graduate students. Details about the department and its facilities can be found at http://earthscience.rice.edu. Please send a CV, research and teaching statements, and names of four or more references to firstname.lastname@example.org. All required application materials submitted by September 15, 2015 are ensured full consideration.
Bigelow: Single Cell Genomics Center (SCGC): Bioinformatician
For full consideration, the application should be received by June 19, 2015.
IFREMER: Life at the extremes: microbial EcoGenomics of deep-sea extremophiles
The Lab for Microbiology of Extreme Environments (LM2E) in Brest (France) has an 18-month postdoctoral position available to carry out research in the field of deep-sea microbial ecology. The position will remain open until it is filled.
Montana State University: PhD Position, Astrobiology
The Priscu Research Group is seeking a motivated Ph.D. Student to work on a recently funded NASA Planetary Science and Technology Through Analog Research (PSTAR) grant.
MBARI: Principle Investigator
The Monterey Bay Aquarium Research Institute (MBARI) seeks a Principal Investigator (PI) to develop and direct a marine carbon cycle research team.
Bermuda Institute of Ocean Sciences: Chemical/Physical/Biological Oceanographer
Review of applications will begin April 15, 2015.
UTK: Professor and Head Department of Microbiology, The College of Arts & Sciences
Review of applications will begin on March 31, 2015 and will continue until the position is filled.
The review of materials will begin December 01, 2014, and will continue until the position is filled.
Skidaway Institute of Oceanography: Two Tenure Track Faculty Positions in Oceanography
The committee will begin to review applications on October 24, 014 and will continue until the positions are filled.
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