113 research outputs found

    Comparison of Na Lidar and Meteor Radar Wind Measurements at Starfire Optical Range, NM, USA

    Get PDF
    Simultaneous wind measurements in the mesopause region at Starfire Optical Range near Albuquerque, NM with Na wind/temperature lidar and meteor radar have been performed and compared. 20 nights of hourly data recorded with these two instruments at two layers around 86 and 93 km altitude are compared for both zonal and meridional wind components. The mean values are found to have no statistically significant differences. The correlation coefficients vary between 0.63 and 0.70, indicating that the two sets of measurements are broadly consistent. When comparing the averaged variations over the night, the two measurements are highly correlated, with correlation coefficients varying from 0.84 to 0.95. It indicates that the strong tidal variation is well captured by both instruments. Differences are however significant at individual hours, which are believed to be mainly due to the fact that the meteor radar wind is an average over the entire sky while the lidar measures wind within a volume about 100 m in diameter

    A Resilience Framework for Critical Infrastructure

    Get PDF
    Infrastructures facilitate economic growth, protect human health and the environment and promote welfare and prosperity. Modern societies, therefore, rely heavily on continuous and reliable services provided critical infrastructure. Destruction to the infrastructure can lead to severe economic and social impacts and can also lead to loss of lives. To further complicate matters, modern infrastructures operate as a ‘system of systems’ with many interactions and interdependencies among these systems. Thus damage in one infrastructure system can cascade and result in failures and cascading effects onto all related and dependent infrastructures. To minimise such damages and impacts, it is vital to improve the resilience of critical infrastructure. This paper intends to present a resilience framework for critical infrastructure. Firstly a resilience definition has been established by reviewing the existing definitions. Then existing resilience frameworks were analysed to identity the suitable components for the proposed framework for critical infrastructure. Finally a layered approach framework has been developed to improve the resilience of critical infrastructure. The framework was developed based on comprehensive literature review. It was further validated with stakeholder feedback sessions. The framework consists of 4 layers that are independent and interdependent. Climatic hazards including current and future climate change, infrastructure, their networks and interdependencies, risks and impacts and capacities are the main layers. Each layer will have its unique features and its relationships with other layers. Climatic hazards will contribute to increased risks and impacts. Critical infrastructure is more vulnerable when exposed to climate hazard and uncertainty of climate change and will lead to risks and impacts. The capacities will help to determine the resilience level and will help to reduce the risks and impact. The framework serves as a diagnostic model to determine the existing resilience level of critical infrastructure and to improve the resilience by making necessary changes to the layers

    Comparison of mesospheric and lower thermospheric residual wind with High Resolution Doppler Imager, medium frequency, and meteor radar winds

    Get PDF
    The objective of this study is to compare observed mean meridional winds with those deduced from theory. The diabatic circulation is computed from High Resolution Dopper Imager (HRDI) mesospheric and lower thermospheric temperatures during January and July conditions. The meridional wind component is compared with HRDI Eulerian mean meridional winds near 95 km and with seasonal averages of meridional winds at a number of radar medium-frequency (MF) and meteor wind (MW) sites. The diabatic wind is directed from the summer toward the winter hemisphere. Peak values exceed 20 m s-1 and are observed at 105 km near 20° in the summer hemisphere. A secondary maximum of about 10 m s-1 is observed in the wintertime lower mesosphere during the July case. The diabatic wind is qualitatively consistent with HRDI 95-km mean meridional winds at latitudes equatorward of 50°. Time-averaged summertime radar winds are consistent with HRDI and diabatic winds between 50° S and 20° N. At winter midlatitudes, MF radar winds are directed oppositely to the diabatic wind, while one available MW measurement is directed with the diabatic wind. The zonal acceleration implied by the diabatic wind is about 150-200 m s-1 d-1 in the midlatitude summer lower thermosphere. Copyright 2000 by the American Geophysical Union

    パルスフィールドゲル電気泳動法(Pulsed-Field Gel Electrophoresis,PFGE)の標準化及び画像診断を基礎とした分散型システムの有効性に関する研究

    Get PDF
    平成13年に北海道で発生した腸管出血性大腸菌感染症のうち、当所が入手したO26及びO157菌株について、パルスフィールドゲル電気泳動法(Pulsed-Field Gel Electrophoresis,PFGE)を用いた疫学的解析を行った。その結果、集団感染事例由来株のPFGEパターンは一致し、散発事例由来株はそれぞれが異なったパターンを示した。このことから、PFGEは菌株を効率よく弁別するのに有効な手段であることが示された

    Proteomic and protein interaction network analysis of human T lymphocytes during cell-cycle entry

    Get PDF
    Proteomic analysis of T cells emerging from quiescence identifies dynamic network-level changes in key cellular processes. Disruption of two such processes, ribosome biogenesis and RNA splicing, reveals that the programs controlling cell growth and cell-cycle entry are separable

    HRDI observations of mean meridional winds at solstice

    Get PDF
    High Resolution Doppler Imager (HRDI) measurements of daytime and nighttime winds at 95 km are used to deduce seasonally averaged Eulerian mean meridional winds during six solstice periods. These estimates are compared with seasonally averaged radar meridional winds and with results from dynamical and empirical wind models. HRDI mean meridional winds are directed from the summer pole toward the winter pole over much of the globe. Peak equatorward winds of about 15 m s-1 are usually observed in the summer hemisphere near 30°. A local minimum in the equatorward winds is often observed poleward of this latitude, with winds approaching zero or reversing direction. A similar structure is seen in contemporaneous radar winds. This behavior differs from residual meridional wind patterns predicted by models. The discrepancies may be related to gravity wave paramaterizations or a consequence of planetary wave influences

    Comparison of mesospheric and lower thermospheric residual wind with High Resolution Doppler Imager, medium frequency, and meteor radar winds

    Get PDF
    The objective of this study is to compare observed mean meridional winds with those deduced from theory. The diabatic circulation is computed from High Resolution Dopper Imager (HRDI) mesospheric and lower thermospheric temperatures during January and July conditions. The meridional wind component is compared with HRDI Eulerian mean meridional winds near 95 km and with seasonal averages of meridional winds at a number of radar medium-frequency (MF) and meteor wind (MW) sites. The diabatic wind is directed from the summer toward the winter hemisphere. Peak values exceed 20 m s−1 and are observed at 105 km near 20° in the summer hemisphere. A secondary maximum of about 10 m s−1 is observed in the wintertime lower mesosphere during the July case. The diabatic wind is qualitatively consistent with HRDI 95-km mean meridional winds at latitudes equatorward of 50°. Time-averaged summertime radar winds are consistent with HRDI and diabatic winds between 50°S and 20°N. At winter midlatitudes, MF radar winds are directed oppositely to the diabatic wind, while one available MW measurement is directed with the diabatic wind. The zonal acceleration implied by the diabatic wind is about 150–200 m s−1 d−1 in the midlatitude summer lower thermosphere.R. S. Lieberman, A. K. Smith, S. J. Franke, R. A. Vincent, J. R. Isler, A. H. Manson, C. E. Meek, G. J. Fraser, A. Fahrutdinova, T. Thayaparan, W. Hocking, J. MacDougall, T. Nakamura, and T. Tsud
    corecore