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多梯度复杂图像的分割 总被引:1,自引:1,他引:0
图像分割是一种重要的图像分析技术,它不仅得到人们广泛的重视和研究,也在实际中得到大量的应用。本文针对一些经典分割算法对多梯度复杂图像分割边缘定位不准确,易受噪声干扰的特点,提出了一种利用图像边缘区域对多梯度复杂图像进行自适应阈值分割的算法。通过对各种算法的比较,本算法抗干扰能力较强,稳定性好,而且完全自动,不需预先设定任何参数。对多种图像的实验表明本文方法十分有效。 相似文献
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孤岛油田馆(1 2)砂层组属于河流相沉积,其纵向、横向相变迅速,砂体难以大面积追踪,本利用河流结构单元分析法、标准层与辅助标志层控制下的“旋回-厚度”对比法,很好地解决了馆(1 2)地层的划分对比问题,其中馆(1 2)砂层组内辅助标志层的发现为地层的划分对比提供了重要的保证.根据结构单元分析、砂体的岩性特征、粒度特征、河流砂体的空间展布形态以及河流曲率的计算,对馆(1 2)河流沉积的垂向旋回性及沉积模式进行了研究。对比Miall的16种河流分类方案,孤岛油田馆(1 2)砂层组属于细粒曲流河沉积. 相似文献
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M. J. R. Aguirre I. Garcia-Acha J. R. Villanueva 《Cellular and molecular life sciences : CMLS》1963,19(2):82-83
Résumé Les auteurs montrent l'action d'une préparation enzymique duStreptomyces GM sur la paroi cellulaire des champignons, donnant lieu à la formation de «protoplastes». De tous les champignons traités avec l'enzyme (strepzime),Fusarium culmorum semble s'être montré le plus sensible à cette digestion enzymatique. 相似文献
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分别运用一般方法和投影法计算了均匀细圆环和均匀薄圆盘对任意轴线的转动惯量,在验证投影法计算结果正确性的基础上,对计算结果进行了讨论,可以用于对实际问题的分析研究. 相似文献
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I. García Acha J. P. G. Ballesta M. J. R. Aguirre J. R. Villanueva 《Cellular and molecular life sciences : CMLS》1966,22(6):378-379
Resumen Se especifican las condiciones óptimas para la preparation de paredes celulares de macroconidios deFusarium culmorum, utilizando el desintegrador de Mickle y se demuestra la pureza de las preparaciones mediante su examen al microscopio de fase y electrónico. 相似文献
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N E Sharpless N Bardeesy K H Lee D Carrasco D H Castrillon A J Aguirre E A Wu J W Horner R A DePinho 《Nature》2001,413(6851):86-91
The cyclin-dependent kinase inhibitor p16INK4a can induce senescence of human cells, and its loss by deletion, mutation or epigenetic silencing is among the most frequently observed molecular lesions in human cancer. Overlapping reading frames in the INK4A/ARF gene encode p16INK4a and a distinct tumour-suppressor protein, p19ARF (ref. 3). Here we describe the generation and characterization of a p16Ink4a-specific knockout mouse that retains normal p19Arf function. Mice lacking p16Ink4a were born with the expected mendelian distribution and exhibited normal development except for thymic hyperplasia. T cells deficient in p16Ink4a exhibited enhanced mitogenic responsiveness, consistent with the established role of p16Ink4a in constraining cellular proliferation. In contrast to mouse embryo fibroblasts (MEFs) deficient in p19Arf (ref. 4), p16Ink4a-null MEFs possessed normal growth characteristics and remained susceptible to Ras-induced senescence. Compared with wild-type MEFs, p16Ink4a-null MEFs exhibited an increased rate of immortalization, although this rate was less than that observed previously for cells null for Ink4a/Arf, p19Arf or p53 (refs 4, 5). Furthermore, p16Ink4a deficiency was associated with an increased incidence of spontaneous and carcinogen-induced cancers. These data establish that p16Ink4a, along with p19Arf, functions as a tumour suppressor in mice. 相似文献
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Transgenic expression and activation of PGC-1α protect dopaminergic neurons in the MPTP mouse model of Parkinson’s disease 总被引:1,自引:1,他引:0
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Comino-Méndez I Gracia-Aznárez FJ Schiavi F Landa I Leandro-García LJ Letón R Honrado E Ramos-Medina R Caronia D Pita G Gómez-Graña A de Cubas AA Inglada-Pérez L Maliszewska A Taschin E Bobisse S Pica G Loli P Hernández-Lavado R Díaz JA Gómez-Morales M González-Neira A Roncador G Rodríguez-Antona C Benítez J Mannelli M Opocher G Robledo M Cascón A 《Nature genetics》2011,43(7):663-667
Hereditary pheochromocytoma (PCC) is often caused by germline mutations in one of nine susceptibility genes described to date, but there are familial cases without mutations in these known genes. We sequenced the exomes of three unrelated individuals with hereditary PCC (cases) and identified mutations in MAX, the MYC associated factor X gene. Absence of MAX protein in the tumors and loss of heterozygosity caused by uniparental disomy supported the involvement of MAX alterations in the disease. A follow-up study of a selected series of 59 cases with PCC identified five additional MAX mutations and suggested an association with malignant outcome and preferential paternal transmission of MAX mutations. The involvement of the MYC-MAX-MXD1 network in the development and progression of neural crest cell tumors is further supported by the lack of functional MAX in rat PCC (PC12) cells and by the amplification of MYCN in neuroblastoma and suggests that loss of MAX function is correlated with metastatic potential. 相似文献
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A new species of the genus Beebeomyia Curran found in central Veracruz (Mexico) is described, including characters of the male and female terminalia, and a key to the identification of the known species is provided. This new species was found feeding within inflorescences of Dieffenbachia oerstedii Schott (Araceae). Larvae were found throughout the inflorescence, with a proportion nearly three times higher in the female (bottom) than the male (top) section. The life cycle from larval stage to adult emergence takes place in an average time of 42 days, while pupation occurs within the inflorescence. Observations of the oviposition behaviour suggest that after oviposition, the female marks the inflorescence with a deterrent pheromone to prevent further ovipositions by other conspecific females.http://zoobank.org/lsid:zoobank.org:pub:DC19F7E5-3AAF-4E5C-A35C-F4872C89D3B4 相似文献