488 research outputs found
On cell problems for Hamilton-Jacobi equations with non-coercive Hamiltonians and its application to homogenization problems
We study a cell problem arising in homogenization for a Hamilton-Jacobi
equation whose Hamiltonian is not coercive. We introduce a generalized notion
of effective Hamiltonians by approximating the equation and characterize the
solvability of the cell problem in terms of the generalized effective
Hamiltonian. Under some sufficient conditions, the result is applied to the
associated homogenization problem. We also show that homogenization for
non-coercive equations fails in general
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Systematic Scatterometer Wind Errors Near Coastal Mountains.
Satellite scatterometers provide the only regular observations of surface wind vectors over vast swaths of the world oceans, including coastal regions, which are of great scientific and societal interest but still present challenges for remote sensing. Here we demonstrate systematic scatterometer wind errors near Hawaii's Big Island: Two counter-rotating lee vortices, which are clear in the International Comprehensive Ocean-Atmosphere Data Set ship-based wind climatology and in aircraft observations, are absent in the Jet Propulsion Laboratory and Remote Sensing Systems scatterometer wind climatologies. We demonstrate similar errors in the representation of transient Catalina Eddy events in the Southern California Bight. These errors likely arise from the nonuniqueness of scatterometer wind observations, that is, an "ambiguity removal" is required during processing to select from multiple wind solutions to the geophysical model function. We discuss strategies to improve the ambiguity selection near coastal mountains, where small-scale wind reversals are common
不規則効果を強調した粘性解析
学位の種別: 課程博士審査委員会委員 : (主査)東京大学教授 儀我 美一, 東京大学教授 片岡 清臣, 東京大学教授 山本 昌宏, 東京大学教授 中村 周, 東京大学准教授 齊藤 宣一University of Tokyo(東京大学
Rhabdomyolysis due to the additive effect of statin therapy and hypothyroidism: a case report
We describe a patient with previously undiagnosed hypothyroidism who developed rhabdomyolysis while taking a statin. He had no other precipitating factors. The statin was stopped, intravenous fluids were started immediately and L-thyroxin was given after confirming the diagnosis of hypothyroidism. His symptoms improved over a few days. Because rhabdomyolysis is a rare but potentially life threatening disorder when complicated by acute tubular necrosis and renal failure, physicians must pay special attention when starting statins in patients with hyperlipidemia
Multiple causes of interannual sea surface temperature variability in the equatorial Atlantic Ocean
The eastern equatorial Atlantic Ocean is subject to interannual fluctuations of sea surface temperatures, with climatic impacts on the surrounding continents. The dynamic mechanism underlying Atlantic temperature variability is thought to be similar to that of the El Nino/Southern Oscillation (ENSO) in the equatorial Pacific, where air-sea coupling leads to a positive feedback between surface winds in the western basin, sea surface temperature in the eastern basin, and equatorial oceanic heat content. Here we use a suite of observational data, climate reanalysis products, and general circulation model simulations to reassess the factors driving the interannual variability. We show that some of the warm events can not be explained by previously identified equatorial wind stress forcing and ENSO-like dynamics. Instead, these events are driven by a mechanism in which surface wind forcing just north of the equator induces warm ocean temperature anomalies that are subsequently advected toward the equator. We find the surface wind patterns are associated with long-lived subtropical sea surface temperature anomalies and suggest they therefore reflect a link between equatorial and subtropical Atlantic variability
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