780 research outputs found

    Republic of Korea – 2009 – I

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    Meteorological and Streamflow Droughts: Characteristics, Trends and Propagation in the Milwaukee River Basin

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    This study examined meteorological and streamflow droughts for the period 1951-2006 using the Milwaukee River basin in Wisconsin as the study area in an effort to improve the understanding of drought propagation. Specifically, this study aimed to answer the following research questions: (1) What are the temporal trends of meteorological and streamflow droughts identified by drought indicators? (2) How do the drought indicators manifest drought propagation? Meteorological droughts were identified using the Effective Drought Index (EDI), and streamflow droughts were identified using a threshold-level approach. The intensity and duration of both types of drought were found to have decreased over time most likely due to increasing precipitation. Therefore, 22 in the study area, and likely in the larger region, drought has become of less concern. The propagation of meteorological drought into streamflow drought was detected generally after moderate and severe sequences of negative EDI that eventually led to extreme meteorological drought events. The study finds that both EDI and the threshold-level approach are effective in diagnosing meteorological and streamflow drought events of all durations

    Reconciling the shadow of a subduction signature with rift geochemistry and tectonic environment in Eastern Marie Byrd Land, Antarctica

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    Basalt-trachyte volcanoes in the Marie Byrd Land (MBL) Cenozoic province lie along the Amundsen Sea coast on the north flank of the West Antarctic rift. Basalts here are characterized by OIB-like geochemistry, restricted ranges of 87Sr/86Sr (0.702535–0.703284) and 143Nd/144Nd (0.512839–0.513008) and a wide range of 206Pb/204Pb (19.357–20.934). Basalts at three MBL volcanoes display two anomalies compared with the above and with all other basalts in West Antarctica. They include 143Nd/144Nd (0.512778–0.512789) values at Mt. Takahe and Mt. Siple that are 2σ lower than other West Antarctic basalts, and Ba/Nb, Ba/La, and Ba/Th values at Mt. Murphy and Mt. Takahe that are 3–8 times higher than normal OIB. Isotope and trace element data do not support crustal and lithospheric mantle contamination, or the presence of residual mantle amphibole or phlogopite as explanations of these anomalies. The apparent coincidence of these anomalies with the site of a pre-Cenozoic convergence zone along the Gondwanaland margin suggests a subduction influence. Major episodes of subduction and granitic plutonism took place in MBL during the Devonian, Permian, and Late Cretaceous. Relicts in the source region, of components from these subducted slabs, provide a credible explanation for the uncoupling of Ba from other large ion lithophile elements (LILE), for its erratic distribution, and for the anomalously low 143Nd/144Nd at Mt. Takahe. The last episode of subduction ended ~ 85 Ma, and was followed by continental break-up, rifting and lithospheric attenuation that produced the West Antarctic rift as we know it today. Thus, the enigmatic geochemical signatures in these three volcanoes seem to have been preserved roughly 61–85 m.y. after subduction ended. New calculations of source melting depth and a new determination of lithospheric thickness suggest that the source of the anomalies resides in a fossil mélange diapir that rose from the Cretaceous subducting slab, became attached to the base of the lithosphere at 80–100 km depth, and remained there during the subsequent plate motion and source remobilization history of this region

    Unmet Healthcare Needs of Children in Vulnerable Families in South Korea: Finding from the Community Child Center Child Panel Survey

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    Presented in this paper is a study that examined the status of unmet healthcare needs of children in vulnerable families and identified factors affecting such unmet needs. The Community Child Center (CCC) Child Panel Survey data in Korea were used. A multiple stepwise logistic regression analysis was performed to examine factors influencing unmet healthcare needs of children. Influencing factors comprised predisposing, enabling, and need factors based on the Andersen Behavioral Model of Health Services Utilization. A total of 340 sixth-graders from vulnerable families participated, and 96 (28.2%) children had unmet healthcare needs. Factors included absence of an after-school caregiver (OR = 1.95, 95% CI [1.16, 3.27]), perceived physical symptoms (OR = 1.33, 95% CI [1.02, 1.73]), parental indifference (OR = 1.33, 95% CI [1.002, 1.77]), duration of daily stay at CCCs (OR = 1.32, 95% CI [1.01, 1.71]), and satisfaction with CCC teachers (OR = 0.65, 95% CI [0.49, 0.85]). The relationship with parents and CCC teachers had the strongest influence on unmet healthcare needs of children. In order to reduce the unmet healthcare needs of children in vulnerable families, existing support structures should be expanded to offer financial and administrative support for children’s parents and CCC teachers

    Distribution of particulate organic matter in the Kum River, Korea

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    Article信州大学理学部附属諏訪臨湖実験所報告 9: 101-110(1995)departmental bulletin pape

    Ultrahigh-efficiency solution-processed simplified small-molecule organic light-emitting diodes using universal host materials

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    Although solution processing of small-molecule organic light-emitting diodes (OLEDs) has been considered as a promising alternative to standard vacuum deposition requiring high material and processing cost, the devices have suffered from low luminous efficiency and difficulty of multilayer solution processing. Therefore, high efficiency should be achieved in simple-structured small-molecule OLEDs fabricated using a solution process. We report very efficient solution-processed simple-structured small-molecule OLEDs that use novel universal electron-transporting host materials based on tetraphenylsilane with pyridine moieties. These materials have wide band gaps, high triplet energy levels, and good solution processabilities; they provide balanced charge transport in a mixed-host emitting layer. Orange-red (similar to 97.5 cd/A, similar to 35.5% photons per electron), green (similar to 101.5 cd/A, similar to 29.0% photons per electron), and white (similar to 74.2 cd/A, similar to 28.5% photons per electron) phosphorescent OLEDs exhibited the highest recorded electroluminescent efficiencies of solution-processed OLEDs reported to date. We also demonstrate a solution-processed flexible solid-state lighting device as a potential application of our devices.

    Nonlinear Analysis of Irregular Variables

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    The Fourier spectral techniques that are common in Astronomy for analyzing periodic or multi-periodic light-curves lose their usefulness when they are applied to unsteady light-curves. We review some of the novel techniques that have been developed for analyzing irregular stellar light or radial velocity variations, and we describe what useful physical and astronomical information can be gained from their use.Comment: 31 pages, to appear as a chapter in `Nonlinear Stellar Pulsation' in the Astrophysics and Space Science Library (ASSL), Editors: M. Takeuti & D. Sasselo
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