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Austin DW Allen MS McCollum JM Dar RD Wilgus JR Sayler GS Samatova NF Cox CD Simpson ML 《Nature》2006,439(7076):608-611
Recent work demonstrates that stochastic fluctuations in molecular populations have consequences for gene regulation. Previous experiments focused on noise sources or noise propagation through gene networks by measuring noise magnitudes. However, in theoretical analysis, we showed that noise frequency content is determined by the underlying gene circuits, leading to a mapping between gene circuit structure and the noise frequency range. An intriguing prediction from our previous studies was that negative autoregulation shifts noise to higher frequencies where it is more easily filtered out by gene networks--a property that may contribute to the prevalence of autoregulation motifs (for example, found in the regulation of approximately 40% of Escherichia coli genes). Here we measure noise frequency content in growing cultures of E. coli, and verify the link between gene circuit structure and noise spectra by demonstrating the negative autoregulation-mediated spectral shift. We further demonstrate that noise spectral measurements provide mechanistic insights into gene regulation, as perturbations of gene circuit parameters are discernible in the measured noise frequency ranges. These results suggest that noise spectral measurements could facilitate the discovery of novel regulatory relationships. 相似文献
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A substantial proportion of contemporary migration flows to the UK are made by nationals from countries which have recently joined the EU. The nature of A8 migration during the recession is examined in this paper, mainly using data from the Worker Registration Scheme. The recession has seen a decline in new A8 migrants entering the UK labour market, but the decline has been sectorally uneven, with demand for migrant labour being most persistent in the agricultural sector, raising questions about why this part of the UK economy is so different. 相似文献
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Gin McCollum 《Foundations of Science》2002,7(1-2):49-72
Nervous systems are intricately organized on many levels of analysis.The intricate organization invites the development of mathematicalsystems that reflect its logical structure. Particular logical structures and choices of invariants within those structures narrowthe ranges of perceptions that are possible and sensorimotorcoordination that may be selected. As in quantum logic, choicesaffect outcomes. Some of the mathematical tools in use in quantum logic havealready also been used in neurobiology, including the mathematicsof ordered structures and a product like a tensor product. Astheoretical neurobiology is developed on its own foundation, wemay expect a rich dialogue between theoretical neurobiology andquantum logic. 相似文献
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