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141.
提出了一种基于小波变换的图像融合方法,并针对该算法对存在局部噪声的图像以及局部噪声和局部模糊并存的图像融合效果不理想的问题,提出了改进算法。弥补了原算法的缺陷。实验证实,改进算法对不同类型的图像具有较好的适应性和鲁棒性.有实用价值。 相似文献
142.
Edwards SL Brough R Lord CJ Natrajan R Vatcheva R Levine DA Boyd J Reis-Filho JS Ashworth A 《Nature》2008,451(7182):1111-1115
Cells with loss of BRCA2 function are defective in homologous recombination (HR) and are highly sensitive to inhibitors of poly(ADP-ribose) polymerase (PARP), which provides the basis for a new therapeutic approach. Here we show that resistance to PARP inhibition can be acquired by deletion of a mutation in BRCA2. We derived PARP-inhibitor-resistant (PIR) clones from the human CAPAN1 pancreatic cancer cell line, which carries the protein-truncating c.6174delT frameshift mutation. PIR clones could form DNA-damage-induced RAD51 nuclear foci and were able to limit genotoxin-induced genomic instability, both hallmarks of a competent HR pathway. New BRCA2 isoforms were expressed in the resistant lines as a result of intragenic deletion of the c.6174delT mutation and restoration of the open reading frame (ORF). Reconstitution of BRCA2-deficient cells with these revertant BRCA2 alleles rescued PARP inhibitor sensitivity and HR deficiency. Most of the deletions in BRCA2 were associated with small tracts of homology, and possibly arose from error-prone repair caused by BRCA2 deficiency. Similar ORF-restoring mutations were present in carboplatin-resistant ovarian tumours from c.6174delT mutation carriers. These observations have implications for understanding drug resistance in BRCA mutation carriers as well as in defining functionally important domains within BRCA2. 相似文献
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Domingues CM Church JA White NJ Gleckler PJ Wijffels SE Barker PM Dunn JR 《Nature》2008,453(7198):1090-1093
Changes in the climate system's energy budget are predominantly revealed in ocean temperatures and the associated thermal expansion contribution to sea-level rise. Climate models, however, do not reproduce the large decadal variability in globally averaged ocean heat content inferred from the sparse observational database, even when volcanic and other variable climate forcings are included. The sum of the observed contributions has also not adequately explained the overall multi-decadal rise. Here we report improved estimates of near-global ocean heat content and thermal expansion for the upper 300 m and 700 m of the ocean for 1950-2003, using statistical techniques that allow for sparse data coverage and applying recent corrections to reduce systematic biases in the most common ocean temperature observations. Our ocean warming and thermal expansion trends for 1961-2003 are about 50 per cent larger than earlier estimates but about 40 per cent smaller for 1993-2003, which is consistent with the recognition that previously estimated rates for the 1990s had a positive bias as a result of instrumental errors. On average, the decadal variability of the climate models with volcanic forcing now agrees approximately with the observations, but the modelled multi-decadal trends are smaller than observed. We add our observational estimate of upper-ocean thermal expansion to other contributions to sea-level rise and find that the sum of contributions from 1961 to 2003 is about 1.5 +/- 0.4 mm yr(-1), in good agreement with our updated estimate of near-global mean sea-level rise (using techniques established in earlier studies) of 1.6 +/- 0.2 mm yr(-1). 相似文献
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旅游空间的规划设计对商业中心的可持续发展具有十分重要的推动作用,但对商业中心旅游空间的研究并不多.从分析重庆市沙坪坝区三峡广场旅游空间的现状及生存问题出发,采用"借空间"的思想,发挥空间思维的想象力;接着在图底理论、联系理论、场所理论3大理论基石的基础上营造三峡广场的旅游空间;最后从物质性空间与非物质性空间的角度深入解剖了广场旅游空间营造的相关因子及营造体系.通过对三峡广场旅游空间的营造,不仅有利于增加当地居民的游憩与休闲场所,也扩大了旅游者购物、娱乐的内容,对三峡广场的多样化、可持续发展有十分重要的意义;同时对其他类似商业中心的生产发展也具有十分重要的借鉴作用. 相似文献
150.
鄂温克族和鄂伦春族舌运动类型的遗传学研究 总被引:9,自引:2,他引:7
调查了内蒙古鄂温克族(共322例,男147例,妇175例0和鄂伦春族(共100例,男40例,女60例0的舌运动类型(卷舌,叠舌,翻舌,尖舌,三叶舌),研究结果显示:(1)鄂温克族的卷舌,翻舌,尖舌以及三叶舌的出现率与内蒙古的鄂伦春族,达斡尔族,汉族,蒙古族,回族相比较,绝大多数存在着显著或极显著性差异,鄂伦春族与达翰尔族之间只有三叶舌的出现率有显著性差异,其它4种舌运动类型的出现率均比较接近,而与内蒙古的族,蒙古族,回族相比较,也只有翻舌的出现率存在显著性差异,但卷舌,叠舌和尖舌的出现率不存在显著性差异,(2)鄂温克族和鄂伦春族间只有尖舌的出现率存在极显著的性别差异。(3)鄂温克族和鄂伦春族在卷舌与三叶舌,翻舌与尖舌以及翻舌与三叶舌间均存在基因互作关系,而卷舌与叠舌间不存在基因互作关系。 相似文献