منابع مشابه
Fifty Thousand Years of Extinction
The Late Quaternary extinction of megafauna has been a ‘‘hot topic’’ of research and debate since at least the time of Darwin (who discussed it in the Origin), but especially since the 1960s when Paul Martin ignited the debate with his theory of prehistoric overkill. The topic has had increasing exposure over the past ten years because of the relevance of this, the most recent palaeontological ...
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BACKGROUND Despite improvements in diagnostic and surgical techniques, operative mortality associated with liver resection is still greater than 2% in most of the recent studies. HYPOTHESIS By refining preoperative and postoperative care and surgical skills, liver resection mortality can be decreased to zero. DESIGN Retrospective cohort study to analyze postoperative morbidity and mortality...
متن کاملFifty years of tachycardia.
In 1943 an otherwise healthy girl aged 3 developed measles encephalitis with an accompanying mild left hemiparesis. At this time a persistent tachycardia of 140 beats per minute was noted, and she was referred to Sir John Parkinson at the National Heart Hospital. He made a diagnosis of atrial tachycardia. A trial of digoxin and quinidine proved ineffective, but she remained symptomatically well...
متن کاملFifty Years of Synchrotrons
The idea of a pulsed magnet ring, fundamental to the synchrotron, appeared in a proposal by Oliphant [1] in 1943 and was followed by the independent discovery of phase stability by Veksler [2] in 1944 and McMillan [3] in 1945. This opened the door to a demonstration of synchrotron acceleration to 8 MeV by Goward and Barnes [4] in a converted betatron at Woolwich Arsenal, UK. The event, which to...
متن کاملFifty Years of Development
Perspectives on development have changed radically over the past half-century, and indeed over the past decade. New evidence and theoretical approaches have deepened and shifted the debates. We have a much better understanding of the relationships among markets, governance, and institutions. Our techniques of empirical analysis and the availability of data have advanced dramatically; indeed one...
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ژورنال
عنوان ژورنال: PLoS Biology
سال: 2011
ISSN: 1545-7885
DOI: 10.1371/journal.pbio.1001186