729 research outputs found
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Gnome site decontamination and decommissioning project
In July 1977, DOE/Headquarters directed DOE/NV to design a decontamination and decommissioning plan for the Gnome site, 48 kilometers southeast of Carlsbad, New Mexico. The plan incorporated three distinct phases. During Phase I, both aerial and ground radiological surveys were conducted on the site. Radiological decontamination criteria were established, and a decontamination plan was developed based on the radiological survey results. During Phase II, site preparatory and rehabilitation work was completed. The actual land area decontamination was accomplished during Phase III with conventional earthmoving equipment. A gravity water injection system deposited 36,700 metric tons of contaminated soil and salt in the Gnome cavity. After completion of the decontamination and decommissioning operations, the Gnome site was returned to the Bureau of Land Management for unrestricted surface use
Facilitating open exchange of data and information
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Earth Science Informatics 8 (2015): 721-739, doi:10.1007/s12145-014-0202-2.By broad consensus, Open Data presents great value. However, beyond that simple statement, there
are a number of complex, and sometimes contentious, issues that the science community must
address. In this review, we examine the current state of the core issues of Open Data with the
unique perspective and use cases of the ocean science community: interoperability; discovery and
access; quality and fitness for purpose; and sustainability. The topics of Governance and Data
Publication are also examined in detail. Each of the areas covered are, by themselves, complex and
the approaches to the issues under consideration are often at odds with each other. Any comprehensive
policy on Open Data will require compromises that are best resolved by broad community input. In
the final section of the review, we provide recommendations that serve as a starting point for these
discussions.The
authors acknowledge the support of the National Science Foundation through Grant Award No.
OCE-1143683.2016-01-0
Waveguide-coupled detector in zero-change complementary metal–oxide–semiconductor
We report a waveguide-coupled photodetector realized in a standard CMOS foundry without requiring changes to the process flow (zero-change CMOS). The photodetector exploits carrier generation in the silicon-germanium normally utilized as stressor in pFETs. The measured responsivity and 3 dB bandwidth are of 0.023 A/W at a wavelength of 1180 nm and 32 GHz at −1 V bias (18 GHz at 0 V bias). The dark current is less than 10 pA and the dynamic range is larger than 60 dB.United States. Defense Advanced Research Projects Agency. Photonically Optimized Embedded Microprocessors Program (Award HR0011-11-C-0100)United States. Defense Advanced Research Projects Agency. Photonically Optimized Embedded Microprocessors Program (Contract HR0011-11-9-0009
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Empirically determined decision levels development and use in an in vivo bioassay program
This paper discusses a method to empirically determine and a use for reporting a decision level value for {sup 137}Cs using a Canberra Accuscan II, direct radiobioassay (in vivo) system. The decision level value is used to determine the upper 5% of in vivo measurements for the purpose of recounting individuals. The paper overviews decision level concepts, the applicability of ANSI N13.30 and ANSI N42.2 and describes the specific process employed
Influence of Igneous Basement on Deep Sediment Microbial Diversity on the Eastern Juan de Fuca Ridge Flank
Microbial communities living in deeply buried sediment may be adapted to long-term energy limitation as they are removed from new detrital energy inputs for thousands to millions of years. However, sediment layers near the underlying oceanic crust may receive inputs from below that influence microbial community structure and/or activity. As part of the Census of Deep Life, we used 16S rRNA gene tag pyrosequencing on DNA extracted from a spectrum of deep sediment-basement interface samples from the subsurface of the Juan de Fuca Ridge flank (collected on IODP Expedition 327) to examine this possible basement influence on deep sediment communities. This area experiences rapid sedimentation, with an underlying basaltic crust that hosts a dynamic flux of hydrothermal fluids that diffuse into the sediment. Chloroflexi sequences dominated tag libraries in all sediment samples, with variation in the abundance of other bacterial groups (e.g., Actinobacteria, Aerophobetes, Atribacteria, Planctomycetes, and Nitrospirae). These variations occur in relation to the type of sediment (clays versus carbonate-rich) and the depth of sample origin, and show no clear connection to the distance from the discharge outcrop or to basement fluid microbial communities. Actinobacteria-related sequences dominated the basalt libraries, but these should be viewed cautiously due to possibilities for imprinting from contamination. Our results indicate that proximity to basement or areas of seawater recharge is not a primary driver of microbial community composition in basal sediment, even though fluids diffusing from basement into sediment may stimulate microbial activity
IODP Deep Biosphere Research Workshop report – a synthesis of recent investigations, and discussion of new research questions and drilling targets
Laser-annealing Josephson junctions for yielding scaled-up superconducting quantum processors
As superconducting quantum circuits scale to larger sizes, the problem of
frequency crowding proves a formidable task. Here we present a solution for
this problem in fixed-frequency qubit architectures. By systematically
adjusting qubit frequencies post-fabrication, we show a nearly ten-fold
improvement in the precision of setting qubit frequencies. To assess
scalability, we identify the types of 'frequency collisions' that will impair a
transmon qubit and cross-resonance gate architecture. Using statistical
modeling, we compute the probability of evading all such conditions, as a
function of qubit frequency precision. We find that without post-fabrication
tuning, the probability of finding a workable lattice quickly approaches 0.
However with the demonstrated precisions it is possible to find collision-free
lattices with favorable yield. These techniques and models are currently
employed in available quantum systems and will be indispensable as systems
continue to scale to larger sizes.Comment: 9 pages, 6 figures, Supplementary Information. Update to correct typo
in author name and in text. Updated acknowledgements and corrected typo in
acknowledgement
Maximum rates of N2 fixation and primary production are out of phase in a developing cyanobacterial bloom in the Baltic Sea
Although N2-fixing cyanobacteria contribute significantly to oceanic sequestration of atmospheric CO2, little is known about how N2 fixation and carbon fixation (primary production) interact in natural populations of marine cyanobacteria. In a developing cyanobacterial bloom in the Baltic Sea, rates of N2 fixation (acetylene reduction) showed both diurnal and longer-term fluctuations. The latter reflected fluctuations in the nitrogen status of the cyanobacterial population and could be correlated with variations in the ratio of acetylene reduced to 15N2 assimilated. The value of this ratio may provide useful information about the release of newly fixed nitrogen by a cyanobacterial population. However, although the diurnal fluctuations in N2 fixation broadly paralleled diurnal fluctuations in carbon fixation, the longer-term fluctuations in these two processes were out of phase
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