6,024 research outputs found

    The development of selected data base applications for the crustal dynamics data information system

    Get PDF
    The development of a data base and its accompanying software for the data information system of crustal dynamics project is described. Background information concerning this project, and a definition of the techniques used in the implementation of an operational data base, are presented. Examples of key applications are included and interpreted

    The Orbit, Mass, and Albedo of Transneptunian Binary 1999 RZ253

    Full text link
    We have observed 1999 RZ253 with the Hubble Space Telescope at seven separate epochs and have fit an orbit to the observed relative positions of this binary. Two orbital solutions have been identified that differ primarily in the inclination of the orbit plane. The best fit corresponds to an orbital period, P=46.263 +0.006/-0.074 days, semimajor axis a=4,660 +/-170 km and orbital eccentricity e=0.460 +/-0.013 corresponding to a system mass m=3.7 +/-0.4 x10^18 kg. For a density of rho = 1000 kg m^-3 the albedo at 477 nm is p = 0.12 +/-0.01, significantly higher than has been commonly assumed for objects in the Kuiper Belt. Multicolor, multiepoch photometry shows this pair to have colors typical for the Kuiper belt with a spectral gradient of 0.35 per 100 nm in the range between 475 and 775 nm. Photometric variations at the four epochs we observed were as large as 12 +/-3% but the sampling is insufficient to confirm the existence of a lightcurve

    IDENTIFICATION AND CLINICAL ASSESSMENT OF DELETION STRUCTURAL VARIANTS IN WHOLE GENOME SEQUENCES OF ACUTELY ILL NEONATES

    Get PDF
    BACKGROUND Effective management of acutely ill newborns with genetic conditions requires rapid and comprehensive identification of causative haplotypes. It has been previously shown that whole genome sequencing (WGS) can identify small variants contributing to the genetic illness of such patients in less than 50 hours. Deletion structural variants (SVs) 50 nucleotides are implicated in many genetic diseases and with WGS data can now be identified with a performance and timeframe sufficient for diagnosis in neonatal intensive care units. Here we describe the development of a solution that combines consensus calls from two SV detection tools (Breakdancer [BD] and GenomeStrip [GS]) with a novel filtering strategy. RESULTS WGS simulation data demonstrated BD and GS consensus calls had 83% sensitivity and 99% positive predictive value with high precision. Through raw data inspection in the integrated genome viewer (IGV) consensus calls overlapping with SNP arrays were found to be 95% true positive and were subsequently used for filter parameterization. Consensus calling and filtering were implemented as a computational pipeline. IGV evaluation of pipeline results in a tetrad demonstrated calls were over 80% true positive but insensitive. Pipeline usage in 10 proband family sets revealed a possibly causative deletion SV in the MMP21 gene for two siblings. MMP21 is thought to play a role in embryogenesis in humans and may be responsible for the heterotaxy phenotype in humans. Further studies are needed to confirm these results. CONCLUSIONS The identification of deletion SVs has the potential to increase the diagnostic yield of WGS data. The methods described in this study may be useful in the research of disease detection in acutely ill neonates

    Regionalizing telecommunications reform in West Africa

    Get PDF
    In recent years, there has been an increasing recognition that significant welfare gains could be realized through deep forms of regional integration which entail harmonization of legal, regulatory and institutional frameworks. Reforms that reduce cross-border transaction costs and improve the performance of “backbone” infrastructure services are arguably even more important for the creation of an open, unified regional economic space than trade policy reforms narrowly defined. This paper assesses the potential gains from regionalized telecommunications policy in West Africa. To this end, the paper: (i) discusses how regional cooperation can overcome national limits in technical expertise, enhance the capacity of nations credibly to commit to stable regulatory policy, and ultimately facilitate infrastructure investment in the region; (ii) identifies trade-distorting regulations that inhibit opportunities for regional trade and economic development, and so are good candidates for regional trade negotiations to reduce indirect trade barriers; and (iii) describes substantive elements of a harmonized regional regulatory policy that can deliver immediate performance benefits.E-Business,Environmental Economics&Policies,ICT Policy and Strategies,Transport Economics Policy&Planning,Emerging Markets

    Discovery of a Binary Centaur

    Get PDF
    We have identified a binary companion to (42355) 2002 CR46 in our ongoing deep survey using the Hubble Space Telescope's High Resolution Camera. It is the first companion to be found around an object in a non-resonant orbit that crosses the orbits of giant planets. Objects in orbits of this kind, the Centaurs, have experienced repeated strong scattering with one or more giant planets and therefore the survival of binaries in this transient population has been in question. Monte Carlo simulations suggest, however, that binaries in (42355) 2002 CR46 -like heliocentric orbits have a high probability of survival for reasonable estimates of the binary's still-unknown system mass and separation. Because Centaurs are thought to be precursors to short period comets, the question of the existence of binary comets naturally arises; none has yet been definitively identified. The discovery of one binary in a sample of eight observed by HST suggests that binaries in this population may not be uncommon.Comment: 20 pages, 4 figures, 1 table accepted for publication in Icaru

    Why Hot Water Pipes in Household Plumbing Burst More Frequently Than Cold Water Pipes

    Get PDF
    Plumbers often notice that the hot water pipes in a plumbing system that lead to the bathroom or kitchen burst more frequently than the pipes carrying cold water. It is said that the ratio is at least four to one. The Cold Water usually freezes so as to lessen the flow of water in the pipes, or to stop the flow altogether, but the freezing seldom bursts the pipes unless the temperature is very low

    ILRS Website Redesign

    Get PDF
    The International Laser Ranging Service (ILRS) website, http://ilrs.gsfc.nasa.gov, is the central source of information for all aspects of the service. The website provides information on the organization and operation of ILRS and descriptions of ILRS components, data, and products. Furthermore, the website and provides an entry point to the archive of these data and products available through the data centers. Links are provided to extensive information on the ILRS network stations including performance assessments and data quality evaluations. Descriptions of supported satellite missions (current, future, and past) are provided to aid in station acquisition and data analysis. The current format for the ILRS website has been in use since the early years of the service. Starting in 2010, the ILRS Central Bureau began efforts to redesign the look and feel for the website. The update will allow for a review of the contents, ensuring information is current and useful. This poster will detail the proposed design including specific examples of key sections and webpages

    Improvements in Space Geodesy Data Discovery at the CDDIS

    Get PDF
    The Crustal Dynamics Data Information System (CDDIS) supports data archiving and distribution activities for the space geodesy and geodynamics community. The main objectives of the system are to store space geodesy and geodynamics related data products in a central data bank. to maintain information about the archival of these data, and to disseminate these data and information in a timely manner to a global scientific research community. The archive consists of GNSS, laser ranging, VLBI, and DORIS data sets and products derived from these data. The CDDIS is one of NASA's Earth Observing System Data and Information System (EOSDIS) distributed data centers; EOSDIS data centers serve a diverse user community and arc tasked to provide facilities to search and access science data and products. Several activities are currently under development at the CDDIS to aid users in data discovery, both within the current community and beyond. The CDDIS is cooperating in the development of Geodetic Seamless Archive Centers (GSAC) with colleagues at UNAVCO and SIO. TIle activity will provide web services to facilitate data discovery within and across participating archives. In addition, the CDDIS is currently implementing modifications to the metadata extracted from incoming data and product files pushed to its archive. These enhancements will permit information about COOlS archive holdings to be made available through other data portals such as Earth Observing System (EOS) Clearinghouse (ECHO) and integration into the Global Geodetic Observing System (GGOS) portal

    Model-Based MR Image Reconstruction WITH Ccompensation FOR THROUGH-Plane Field Inhomogeneity

    Full text link
    To improve image quality in susceptibility-weighted MR imaging, it is important to correct for the effects of field inhomogeneity. In particular, susceptibility differences between air and tissue induce magnetic field nonuniformity; often those susceptibility effects have nonzero through-plane gradients that lead to spin dephasing across the slice within each voxel. If uncorrected, these through-plane gradients cause signal loss in the reconstructed images. Several methods exist for reconstructing MR images with compensation for field inhomogeneity, but most of these methods, even the model-based iterative ones, treat the inhomogeneity within each voxel as being a constant, thus ignoring the through-plane gradient effects. This paper describes a model-based iterative method for reconstructing MR images with compensation for field inhomogeneity that accounts for the slice profile and the through-plane gradients of the field inhomogeneity (assumed to be determined by a pre-scan). In particular, this paper describes an accelerated algorithm for implementing the forward model and its adjoint as needed in a conjugate gradient algorithm for iterative MR image reconstruction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85828/1/Fessler226.pd
    corecore