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Background removal from global auroral images:Data-driven dayglow modeling

Earth and Planetary Physics 2024年第1期8卷 247-257页

作者： a.ohma M.Madelaire K.M.Laundal J.P.Reistad S.M.Hatch S.Gasparini S.J.Walker Birkeland Centre for Space Science Department of Physics and TechnologyUniversity of BergenBergenNorway

Global images of auroras obtained by cameras on spacecraft are a key tool for studying the near-Earth environment.However,the cameras are sensitive not only to auroral emissions produced by precipitating particles,but also to dayglow emissions produced by photoelectrons induced by sunlight.Nightglow emissions and scattered sunlight can contribute to the background signal.To fully utilize such images in space science,background contamination must be removed to isolate the auroral signal.Here we outline a data-driven approach to modeling the background intensity in multiple images by formulating linear inverse problems based on B-splines and spherical harmonics.The approach is robust,flexible,and iteratively deselects outliers,such as auroral emissions.The final model is smooth across the terminator and accounts for slow temporal variations and large-scale asymmetries in the dayglow.We demonstrate the model by using the three far ultraviolet cameras on the Imager for Magnetopause-to-Aurora Global Exploration(IMAGE)mission.The method can be applied to historical missions and is relevant for upcoming missions,such as the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.

关键词： aurora dayglow modeling global auroral images far ultraviolet images dayglow removal

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急性冠脉综合征的危险分层和治疗决策制定

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美国医学会杂志（中文版） 2001年第4期20卷 208-210页

作者： ohma EM Gran CB Division of Cardiology Department of Medicine and Department of Community and Family Medicine Duke Clinical Research Institute Duke University Medical Center Durham NC

近年来急性冠脉综合征的治疗取得了长足的进步,正像80年代急性心肌梗死(MI)的治疗进展.当时纤维蛋白溶解和阿司匹林治疗显著降低了死亡率1.虽然这些治疗首先用于所有可疑MI的患者1,但ST段抬高或左束支阻滞的患者(即使不是全部)也获得了... 详细信息

近年来急性冠脉综合征的治疗取得了长足的进步,正像80年代急性心肌梗死(MI)的治疗进展.当时纤维蛋白溶解和阿司匹林治疗显著降低了死亡率1.虽然这些治疗首先用于所有可疑MI的患者1,但ST段抬高或左束支阻滞的患者(即使不是全部)也获得了极大的疗效2.此后,在普遍使用链激酶和组织纤溶酶原激活剂(tPA)治疗闭塞性冠状动脉(GUSTO-Ⅰ)的试验中,发现加速的tPA优于链激酶,30天的死亡率相对下降14%3.死亡率模式提示tPA治疗(不依赖其他因素)预后较好,该结果在所有亚组中均如此,与绝对危险性无关4.既然未发现不同的治疗效果,这说明几乎所有MI患者会从tPA治疗获益.

关键词：急性冠状动脉综合征治疗危险性

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