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排序方式: 共有306条查询结果,搜索用时 15 毫秒
1.
Samuel Portmann Adrian Wüthrich 《Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics》2007,38(4):844-862
According to Bell's theorem a large class of hidden-variable models obeying Bell's notion of local causality (LC) conflict with the predictions of quantum mechanics. Recently, a Bell-type theorem has been proven using a weaker notion of LC, yet assuming the existence of perfectly correlated event types. Here we present a similar Bell-type theorem without this latter assumption. The derived inequality differs from the Clauser–Horne inequality by some small correction terms, which render it less constraining. 相似文献
2.
Alternative splicing and genome complexity. 总被引:26,自引:0,他引:26
Alternative splicing of mRNA allows many gene products with different functions to be produced from a single coding sequence. It has recently been proposed as a mechanism by which higher-order diversity is generated. Here we show, using large-scale expressed sequence tag (EST) analysis, that among seven different eukaryotes the amount of alternative splicing is comparable, with no large differences between humans and other animals. 相似文献
3.
Persistence of soil organic matter as an ecosystem property 总被引:65,自引:0,他引:65
Schmidt MW Torn MS Abiven S Dittmar T Guggenberger G Janssens IA Kleber M Kögel-Knabner I Lehmann J Manning DA Nannipieri P Rasse DP Weiner S Trumbore SE 《Nature》2011,478(7367):49-56
Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily--and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming. 相似文献
4.
Samuel CS Hewitson TD Unemori EN Tang ML 《Cellular and molecular life sciences : CMLS》2007,64(12):1539-1557
The peptide hormone relaxin is emerging as a multi-functional factor in a broad range of target tissues including several
non-reproductive organs, in addition to its historical role as a hormone of pregnancy. This review discusses the evidence
that collectively demonstrates the many diverse and vital roles of relaxin: the homeostatic role of endogenous relaxin in
mammalian pregnancy and ageing; its gender-related effects; the therapeutic effects of relaxin in the treatment of fibrosis,
inflammation, cardioprotection, vasodilation and wound healing (angiogenesis) amongst other pathophysiological conditions,
and its potential mechanism of action. Furthermore, translational issues using experimental models (to humans) and its use
in various clinical trials, are described, each with important lessons for the design of future trials involving relaxin.
The diverse physiological and pathological roles for relaxin have led to the search for its significance in humans and highlight
its potential as a drug of the future.
Received 12 December 2006; received after revision 12 February 2007; accepted 15 March 2007 相似文献
5.
Guerlin C Bernu J Deléglise S Sayrin C Gleyzes S Kuhr S Brune M Raimond JM Haroche S 《Nature》2007,448(7156):889-893
The irreversible evolution of a microscopic system under measurement is a central feature of quantum theory. From an initial state generally exhibiting quantum uncertainty in the measured observable, the system is projected into a state in which this observable becomes precisely known. Its value is random, with a probability determined by the initial system's state. The evolution induced by measurement (known as 'state collapse') can be progressive, accumulating the effects of elementary state changes. Here we report the observation of such a step-by-step collapse by non-destructively measuring the photon number of a field stored in a cavity. Atoms behaving as microscopic clocks cross the cavity successively. By measuring the light-induced alterations of the clock rate, information is progressively extracted, until the initially uncertain photon number converges to an integer. The suppression of the photon number spread is demonstrated by correlations between repeated measurements. The procedure illustrates all the postulates of quantum measurement (state collapse, statistical results and repeatability) and should facilitate studies of non-classical fields trapped in cavities. 相似文献
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