67 research outputs found

    NASA Image eXchange (NIX)

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    This paper discusses the technical aspects of and the project background for the NASA Image exchange (NIX). NIX, which provides a single entry point to search selected image databases at the NASA Centers, is a meta-search engine (i.e., a search engine that communicates with other search engines). It uses these distributed digital image databases to access photographs, animations, and their associated descriptive information (meta-data). NIX is available for use at the following URL: http://nix.nasa.gov./NIX, which was sponsored by NASAs Scientific and Technical Information (STI) Program, currently serves images from seven NASA Centers. Plans are under way to link image databases from three additional NASA Centers. images and their associated meta-data, which are accessible by NIX, reside at the originating Centers, and NIX utilizes a virtual central site that communicates with each of these sites. Incorporated into the virtual central site are several protocols to support searches from a diverse collection of database engines. The searches are performed in parallel to ensure optimization of response times. To augment the search capability, browse functionality with pre-defined categories has been built into NIX, thereby ensuring dissemination of 'best-of-breed' imagery. As a final recourse, NIX offers access to a help desk via an on-line form to help locate images and information either within the scope of NIX or from available external sources

    Sea Ice Outlook for September 2017 July Report - NASA Global Modeling and Assimilation Office

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    The GMAO seasonal forecast is produced from coupled model integrations that are initialized every five days, with seven additional ensemble members generated by coupled model breeding and initialized on the date closest to the beginning of the month. The main components of the AOGCM are the GEOS-5 atmospheric model, the MOM4 ocean model, and CICE sea ice model. Forecast fields were re-gridded to the passive microwave grid for averaging

    Sea Ice Outlook for September 2017: June Report - NASA Global Modeling and Assimilation Office

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    The GMAO seasonal forecast is produced from coupled model integrations that are initialized every five days, with seven additional ensemble members generated by coupled model breeding and initialized on the date closest to the beginning of the month. The main components of the AOGCM are the GEOS-5 atmospheric model, the MOM4 ocean model, and CICE sea ice model. Forecast fields were re-gridded to the passive microwave grid for averaging

    Two Evolutionary Histories in the Genome of Rice: the Roles of Domestication Genes

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    Genealogical patterns in different genomic regions may be different due to the joint influence of gene flow and selection. The existence of two subspecies of cultivated rice provides a unique opportunity for analyzing these effects during domestication. We chose 66 accessions from the three rice taxa (about 22 each from Oryza sativa indica, O. sativa japonica, and O. rufipogon) for whole-genome sequencing. In the search for the signature of selection, we focus on low diversity regions (LDRs) shared by both cultivars. We found that the genealogical histories of these overlapping LDRs are distinct from the genomic background. While indica and japonica genomes generally appear to be of independent origin, many overlapping LDRs may have originated only once, as a result of selection and subsequent introgression. Interestingly, many such LDRs contain only one candidate gene of rice domestication, and several known domestication genes have indeed been “rediscovered” by this approach. In summary, we identified 13 additional candidate genes of domestication

    NASA GMAO GEOS S2S Prediction System: Metrics, Post-Processing and Products

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    In this presentation we present an overview of the GMAO Sub-Seasonal and Seasonal Prediction System, current users and products, and methods for validation and evaluation of the system. Methods for evaluation include baseline evaluations metrics, the ability to simulate key modes of variability, and evaluation of new development areas

    Genes That Influence Swarming Motility and Biofilm Formation in Variovorax paradoxus EPS

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    Variovorax paradoxus is an aerobic soil bacterium associated with important biodegradative processes in nature. We use V. paradoxus EPS to study multicellular behaviors on surfaces.We recovered flanking sequence from 123 clones in a Tn5 mutant library, with insertions in 29 different genes, selected based on observed surface behavior phenotypes. We identified three genes, Varpa_4665, Varpa_4680, and Varpa_5900, for further examination. These genes were cloned into pBBR1MCS2 and used to complement the insertion mutants. We also analyzed expression of Varpa_4680 and Varpa_5900 under different growth conditions by qPCR.The 29 genes we identified had diverse predicted functions, many in exopolysaccharide synthesis. Varpa_4680, the most commonly recovered insertion site, encodes a putative N-acetyl-L-fucosamine transferase similar to WbuB. Expression of this gene in trans complemented the mutant fully. Several unique insertions were identified in Varpa_5900, which is one of three predicted pilY1 homologs in the EPS genome. No insertions in the two other putative pilY1 homologs present in the genome were identified. Expression of Varpa_5900 altered the structure of the wild type swarm, as did disruption of the chromosomal gene. The swarming phenotype was complemented by expression of Varpa_5900 from a plasmid, but biofilm formation was not restored. Both Varpa_4680 and Varpa_5900 transcripts were downregulated in biofilms and upregulated during swarming when compared to log phase culture. We identified a putative two component system (Varpa_4664-4665) encoding a response regulator (shkR) and a sensor histidine kinase (shkS), respectively. Biofilm formation increased and swarming was strongly delayed in the Varpa_4665 (shkS) mutant. Complementation of shkS restored the biofilm phenotype but swarming was still delayed. Expression of shkR in trans suppressed biofilm formation in either genetic background, and partially restored swarming in the mutant.The data presented here point to complex regulation of these surface behaviors

    Randomized comparison of distal protection with a filter-based catheter and a balloon occlusion and aspiration system during percutaneous intervention of diseased saphenous vein aorto-coronary bypass grafts.

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    BACKGROUND: The high rate of periprocedural complications resulting from atherothrombotic embolization after percutaneous intervention in diseased saphenous vein grafts is reduced by distal microcirculatory protection using a balloon occlusion and aspiration system. Whether filter-based catheters, which offer the inherent advantages of maintained perfusion and ease of use, are as effective for this purpose has not been established. METHODS AND RESULTS: A total of 651 patients undergoing percutaneous intervention of 682 saphenous vein graft lesions were prospectively randomized to distal protection with the filter-based FilterWire EX versus the GuardWire balloon occlusion and aspiration system. Device success was 95.5% and 97.2% with the FilterWire EX and GuardWire, respectively (P=0.25). Postprocedural measures of epicardial flow and angiographic complications were similar between the 2 groups, although bailout IIb/IIIa inhibitors were required slightly less frequently in the FilterWire EX group (0% versus 1.5%, P=0.03). The primary end point, the composite incidence of death, myocardial infarction, or target vessel revascularization at 30 days, occurred in 9.9% of FilterWire EX patients and 11.6% of GuardWire patients (difference [95% CI]=-1.7% [-6.4%, 3.1%]; P for superiority=0.53, P for noninferiority=0.0008). CONCLUSIONS: Distal protection with the FilterWire EX may be safely used as an adjunct to percutaneous intervention of diseased saphenous vein grafts and, compared with distal protection with the GuardWire balloon occlusion and aspiration system, results in similar rates of major adverse cardiac events at 30 days
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