2004年12月26日苏门答腊特大地震是过去50年间在俯冲带发生的第三大地震。其破裂开始于锡默卢岛西北部30~40km深处(Lay et al,2005),传播1300km至安达曼群岛北部(Ammon et al,2005)。这次大地震是由俯冲的印度-澳大利亚板块与上部的巽...
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2004年12月26日苏门答腊特大地震是过去50年间在俯冲带发生的第三大地震。其破裂开始于锡默卢岛西北部30~40km深处(Lay et al,2005),传播1300km至安达曼群岛北部(Ammon et al,2005)。这次大地震是由俯冲的印度-澳大利亚板块与上部的巽他板块之间界面的突然滑动引起的(r.ie et al,2007;Vigny et al,2005)。尽管俯冲界面结构的详细认识对于确定大型逆冲地震潜在源非常重要,但是,目前为止可用的数据(Henstock et al,2006;Sibuet et al,2007;Dewey et al,2007;Engdahlet al,2007)还无法提供这样的信息。本文展示了震源区一条高质量的地震剖面,其展布从深海平原向下延伸到弧前下面40km。地震数据显示,俯冲地壳和大洋莫霍面(地壳-地幔边界)被陆向倾斜的逆冲断层损坏并移位,意味着此大型逆冲断层目前位于大洋地幔内。我们对增生楔前缘的活动逆冲断层成像,其特点与陡峭倾斜面上的逆冲型余震一致。我们的观测结果表明,是壳幔间的强耦合导致地幔岩石脆性破裂,从而引发此次异常大的地震。
Objective The pur.ose of this study was to deter.ine whether.an intr. par.um as sessment of amniotic fluid identifies a pr.gnancy that is at r.sk for.an adver.e outcome. Study design Par.ur.ents who wer. admitted for....
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Objective The pur.ose of this study was to deter.ine whether.an intr. par.um as sessment of amniotic fluid identifies a pr.gnancy that is at r.sk for.an adver.e outcome. Study design Par.ur.ents who wer. admitted for.deliver. wer. assigned r.ndomly to have the amniotic fluid assessed either.by amniotic fluid index or.b y the pr.sence of a 2 ×1 pocket. r.sults The amniotic fluid index was obtained in 499 pr.gnancies, and the 2 ×1 technique was per.or.ed in 501. Oligohydr.mnio s was diagnosed in 25%of amniotic fluid index pr.gnancies ver.us 8%with the us e of the 2 ×1 pocket technique (P r.ent an amnioinfusion for.fetal distr.ss (P=.864) or.who exper. enced var.able (P=.208) or.late deceler.tions (P=.210) that influenced deliver., fetal distr.ss in labor.(P=.220), caesar.an deliver. for.fetal distr.ss (P=.133 ), and admission to neonatal intensive car. unit (P=.686). Conclusion Neither.th e amniotic fluid index nor.the 2 ×1 pocket technique that was under.aken as a f etal admission test identi fies a pr.gnancy that is at r.sk for.an adver.e outco me.
Objective: To investigate the effect of catar.ct extr.ction on the visual fiel ds of patients with open-angle glaucoma. Methods: Patients in a pr.spective coh or. study in a ter.iar. center.under.ent standar. automate...
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Objective: To investigate the effect of catar.ct extr.ction on the visual fiel ds of patients with open-angle glaucoma. Methods: Patients in a pr.spective coh or. study in a ter.iar. center.under.ent standar. automated per.metr. ever. 6 mo nths. We compar.d the mean r.sults of the 2 examinations immediately befor. and 2 examinations immediately after.phacoemulsifi-cation catar.ct extr.ction and i ntr.ocular.lens implant (effect analysis) and the mean r.sults of the fir.t 2 an d last 2 examinations fr.m 4 consecutive examinations obtained mor. than 1 year.after.the catar.ct sur.er. (contr.l analysis). r.sults: Our.sample contained 34 eyes of 26 patients (mean±SD age, 69.2±10.8 year.). While the mean log-MAr.be st-cor.ected visual acuity impr.ved significantly by appr.ximately 2 Snellen li nes after.sur.er. (Pr.ge change in mean deviation in both the eff ect and contr.l analyses was less than 0.1 dB and not statistically significant (P=.85). Ther. was a str.ng cor.elation between change in foveal sensitivity and change in mean deviation in the effect analysis but not in the contr.l analysis (r.0.76 [Pr.0.30 [P=.08], r.spectively). Ther. was no r.lations hip between change in visual acuity or.initial mean deviation and change in mean dev iation in either.analysis. Change in pointwise total deviation was not systemati cally r.lated to the r.spective baseline value in either.analysis; however. the var.ance of the distr.bution of change in total deviation was significantly high er.in the effect analysis (Pr. was an impr.vement in best-cor.ected visual acuity after.catar.ct sur.er., the changes in the visu al field as a gr.up wer. negligible.
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