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Allan Chapman 《Annals of science》2013,70(5):431-463
When Thomas Hornsby commissioned John Bird to build a set of five major astronomical instruments for the new Radcliffe Observatory, Oxford, the order included an Equatorial Sector. This was an instrument of experimental design, intended to measure angles out of the meridian. Although in itself a transitional instrument, the Equatorial Sector's capacity for extra-meridional measurement, especially for the observation of comets, encouraged craftsmen to develop the design first into the Equatorial Circle, and then into the large equatorially mounted refracting telescope used in conjunction with micrometers. Although other Equatorial Sectors were made, Bird's instrument for Oxford is the only one that survives intact. The present study examines this unique artefact within the context of changing astronomical demands between the 1770s and the 1820s. 相似文献
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Complex gas hydrate from the Cascadia margin 总被引:3,自引:0,他引:3
Lu H Seo YT Lee JW Moudrakovski I Ripmeester JA Chapman NR Coffin RB Gardner G Pohlman J 《Nature》2007,445(7125):303-306
Natural gas hydrates are a potential source of energy and may play a role in climate change and geological hazards. Most natural gas hydrate appears to be in the form of 'structure I', with methane as the trapped guest molecule, although 'structure II' hydrate has also been identified, with guest molecules such as isobutane and propane, as well as lighter hydrocarbons. A third hydrate structure, 'structure H', which is capable of trapping larger guest molecules, has been produced in the laboratory, but it has not been confirmed that it occurs in the natural environment. Here we characterize the structure, gas content and composition, and distribution of guest molecules in a complex natural hydrate sample recovered from Barkley canyon, on the northern Cascadia margin. We show that the sample contains structure H hydrate, and thus provides direct evidence for the natural occurrence of this hydrate structure. The structure H hydrate is intimately associated with structure II hydrate, and the two structures contain more than 13 different hydrocarbon guest molecules. We also demonstrate that the stability field of the complex gas hydrate lies between those of structure II and structure H hydrates, indicating that this form of hydrate is more stable than structure I and may thus potentially be found in a wider pressure-temperature regime than can methane hydrate deposits. 相似文献
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Dawson MA Prinjha RK Dittmann A Giotopoulos G Bantscheff M Chan WI Robson SC Chung CW Hopf C Savitski MM Huthmacher C Gudgin E Lugo D Beinke S Chapman TD Roberts EJ Soden PE Auger KR Mirguet O Doehner K Delwel R Burnett AK Jeffrey P Drewes G Lee K Huntly BJ Kouzarides T 《Nature》2011,478(7370):529-533
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Dunham A Matthews LH Burton J Ashurst JL Howe KL Ashcroft KJ Beare DM Burford DC Hunt SE Griffiths-Jones S Jones MC Keenan SJ Oliver K Scott CE Ainscough R Almeida JP Ambrose KD Andrews DT Ashwell RI Babbage AK Bagguley CL Bailey J Bannerjee R Barlow KF Bates K Beasley H Bird CP Bray-Allen S Brown AJ Brown JY Burrill W Carder C Carter NP Chapman JC Clamp ME Clark SY Clarke G Clee CM Clegg SC Cobley V Collins JE Corby N Coville GJ Deloukas P Dhami P Dunham I Dunn M Earthrowl ME Ellington AG 《Nature》2004,428(6982):522-528
Chromosome 13 is the largest acrocentric human chromosome. It carries genes involved in cancer including the breast cancer type 2 (BRCA2) and retinoblastoma (RB1) genes, is frequently rearranged in B-cell chronic lymphocytic leukaemia, and contains the DAOA locus associated with bipolar disorder and schizophrenia. We describe completion and analysis of 95.5 megabases (Mb) of sequence from chromosome 13, which contains 633 genes and 296 pseudogenes. We estimate that more than 95.4% of the protein-coding genes of this chromosome have been identified, on the basis of comparison with other vertebrate genome sequences. Additionally, 105 putative non-coding RNA genes were found. Chromosome 13 has one of the lowest gene densities (6.5 genes per Mb) among human chromosomes, and contains a central region of 38 Mb where the gene density drops to only 3.1 genes per Mb. 相似文献
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Deloukas P Earthrowl ME Grafham DV Rubenfield M French L Steward CA Sims SK Jones MC Searle S Scott C Howe K Hunt SE Andrews TD Gilbert JG Swarbreck D Ashurst JL Taylor A Battles J Bird CP Ainscough R Almeida JP Ashwell RI Ambrose KD Babbage AK Bagguley CL Bailey J Banerjee R Bates K Beasley H Bray-Allen S Brown AJ Brown JY Burford DC Burrill W Burton J Cahill P Camire D Carter NP Chapman JC Clark SY Clarke G Clee CM Clegg S Corby N Coulson A Dhami P Dutta I Dunn M Faulkner L Frankish A 《Nature》2004,429(6990):375-381