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排序方式: 共有134条查询结果,搜索用时 15 毫秒
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Rapid removal of Chernobyl fallout from Mediterranean surface waters by biological activity 总被引:1,自引:0,他引:1
The sinking of particulate organic matter from the euphotic zone is an important pathway for the vertical transport of many elements and organic compounds in the sea. Many natural and artificial radionuclides in surface waters are readily adsorbed onto suspended particles and are presumably scavenged and removed to depth on time scales commensurate with both particle sinking rate and retention time of the radionuclide on the particle. Previously, abyssal benthic organisms from the northeast Pacific were found to contain short-lived fission products which entered the sea surface as fallout from nuclear testing. The presence of these radionuclides at great depth could not be explained by Stokesian settling of small fallout particles and it was hypothesized that zooplankton grazing in the surface layers packaged these particle-reactive radionuclides into large, relatively dense faecal pellets which rapidly sank to depth. We report here data from a time-series sediment trap experiment and concomitant zooplankton collections which show conclusively that Chernobyl radioactivity, in particular the rare earth nuclides 141Ce and 144Ce, entering the Mediterranean as a single pulse, was rapidly removed from surface waters and transported to 200 m in a few days primarily by zooplankton grazing. 相似文献
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Tao Thien Nguyen Hoa Thi Ninh Nikolai Orlov Truong Quang Nguyen Thomas Ziegler 《Journal of Natural History》2020,54(1-4):257-273
ABSTRACT A new rhacophorid species is described from Vietnam on the basis of nine specimens collected in Quan Ba District, Ha Giang Province, northeastern Vietnam. The new species is morphologically similar to Zhangixalus pinglongensis, Z. dorsoviridis, and Z. nigropunctatus, however, it differs from the latter by having the flank cream with large black blotches on axilla and groin. The genetic distance between the new species and Zhangixalus pinglongensis, Z. dorsoviridis and Z. nigropunctatus is >3.57% (16S mtDNA gene fragment). Zhangixalus jodiae sp. nov. can be distinguished from all other species of Zhangixalus and other small rhacophorid species from Southeast Asia by a combination of the following characters: size small (SVL 36.1–39.8 mm in males); head as long as wide; vomerine teeth present; dorsal surface of head and body green without spots; axilla cream with large black blotches, groin and front-rear parts of the thigh, ventral surface of tibia black with orange blotches; lower jaw region greyish, chest and belly cream. http://www.zoobank.org/urn:lsid:zoobank.org:pub:89597718-024F-4FFC-B0AE-2005F12CF66C 相似文献
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语言的死亡,就是指一种语言在一个国家当前全球一体化和都市化两种社会因素影响下从安全到不安全的过程。从安全到不安全从而导致语言死亡是一段危机程度各不相同的距离,且语言的不安全不仅只对人口稀少的少数民族语言而言,也对人口众多的少数民族语言而言,甚至还可用于在当前全球一体化趋势下国家语言所面临的英语危机,以及在国家都市化趋势下方言所面临的消亡危机。 相似文献
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Tarpey PS Raymond FL Nguyen LS Rodriguez J Hackett A Vandeleur L Smith R Shoubridge C Edkins S Stevens C O'Meara S Tofts C Barthorpe S Buck G Cole J Halliday K Hills K Jones D Mironenko T Perry J Varian J West S Widaa S Teague J Dicks E Butler A Menzies A Richardson D Jenkinson A Shepherd R Raine K Moon J Luo Y Parnau J Bhat SS Gardner A Corbett M Brooks D Thomas P Parkinson-Lawrence E Porteous ME Warner JP Sanderson T Pearson P Simensen RJ Skinner C Hoganson G Superneau D Wooster R Bobrow M 《Nature genetics》2007,39(9):1127-1133
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T. D. Nguyen J. Cornillet-Stoupy P. Gillery F. X. Maquart 《Cellular and molecular life sciences : CMLS》1991,47(7):725-728
Summary Dermal equivalents (DE), collagen lattices, were produced in vitro and used as a model for studying the possible role of a pure population of fibroblasts in post-radiotherapeutic dermal fibrosis. Single doses of gamma irradiation induced a partial inhibition of the collagen lattice retraction and of protein synthesis. The collagen production was less inhibited than was synthesis of non-collagen protein, which resulted in an increase of the relative amount of collagen synthesized by irradiated fibroblasts. These data suggest that gamma irradiation might be able to select some fibroblast clones able to produce increasing amounts of collagen. This selection process could be involved in the development of tissue fibrosis after therapeutic radiation. 相似文献
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Morin RD Mendez-Lago M Mungall AJ Goya R Mungall KL Corbett RD Johnson NA Severson TM Chiu R Field M Jackman S Krzywinski M Scott DW Trinh DL Tamura-Wells J Li S Firme MR Rogic S Griffith M Chan S Yakovenko O Meyer IM Zhao EY Smailus D Moksa M Chittaranjan S Rimsza L Brooks-Wilson A Spinelli JJ Ben-Neriah S Meissner B Woolcock B Boyle M McDonald H Tam A Zhao Y Delaney A Zeng T Tse K Butterfield Y Birol I Holt R Schein J Horsman DE Moore R Jones SJ Connors JM Hirst M Gascoyne RD Marra MA 《Nature》2011,476(7360):298-303
Follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) are the two most common non-Hodgkin lymphomas (NHLs). Here we sequenced tumour and matched normal DNA from 13 DLBCL cases and one FL case to identify genes with mutations in B-cell NHL. We analysed RNA-seq data from these and another 113 NHLs to identify genes with candidate mutations, and then re-sequenced tumour and matched normal DNA from these cases to confirm 109 genes with multiple somatic mutations. Genes with roles in histone modification were frequent targets of somatic mutation. For example, 32% of DLBCL and 89% of FL cases had somatic mutations in MLL2, which encodes a histone methyltransferase, and 11.4% and 13.4% of DLBCL and FL cases, respectively, had mutations in MEF2B, a calcium-regulated gene that cooperates with CREBBP and EP300 in acetylating histones. Our analysis suggests a previously unappreciated disruption of chromatin biology in lymphomagenesis. 相似文献