9 resultados para Gray, Chester Earl, 1881-1944.
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
The main factors affecting interrill erosion-including runoff discharge, rainfall intensity, mean flow velocity, and slope gradient-were analyzed by using a gray relational analysis. An equation for interrill erosion was derived by coupling this analysis with dimensional and regression analyses. The values of erosion rates predicted by this equation were in good agreement with experimental observations.
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Intrinsically fuzzy morphological erosion and dilation are extended to a total of eight operations that have been formulated in terms of a single morphological operation--biased dilation. Based on the spatial coding of a fuzzy variable, a bidirectional projection concept is proposed. Thus, fuzzy logic operations, arithmetic operations, gray-scale dilation, and erosion for the extended intrinsically fuzzy morphological operations can be included in a unified algorithm with only biased dilation and fuzzy logic operations. To execute this image algebra approach we present a cellular two-layer processing architecture that consists of a biased dilation processor and a fuzzy logic processor. (C) 1996 Optical Society of America
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An ordered gray-scale erosion is suggested according to the definition of hit-miss transform. Instead of using three operations, two images, and two structuring elements, the developed operation requires only one operation and one structuring element, but with three gray-scale levels. Therefore, a union of the ordered gray-scale erosions with different structuring elements can constitute a simple image algebra to program any combined image processing function. An optical parallel ordered gray-scale erosion processor is developed based on the incoherent correlation in a single channel. Experimental results are also given for an edge detection and a pattern recognition. (C) 1998 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(98)00306-7].
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本论文包括两部分的内容,第一部分是秦岭苔类植物的区系研究,第二部分是中国剪叶苔属Herbertus的分类学修订。 秦岭位于我国的中部,东经104º30´~112º52´,北纬32º50´~34º45´N,约76 500 km2。它主要位于陕西省的南部地区,并包括了河南、甘肃和湖北的部分县、市。秦岭的最高峰是太白山,海拔3 767米。秦岭是长江和黄河的分水岭,也是我国温带和亚热带气候的过渡地带。 本研究包含了对自19世纪开始对秦岭苔藓植物的主要采集活动的回顾,和截止2008年以来对秦岭苔类和角苔类植物报道的总结和分析,且首次给出了一份秦岭地区详细的苔类植物的名录,并包括了各个种在秦岭地区的详细分布。根据目前的研究,现已知秦岭的苔类植物有226种(包括种下单位,以下同),其中角苔纲1科3属6种,苔纲30科59属220种;提出了1个新异名:Radula constricta Steph.被处理为Radula lindenbergiana Gottsche var. atypa Massalongo的异名;并提出了1个新组合Metzgeria pubescens var. kinabaluensis (Kuwah) F.X. Li & Y. Jia;发现秦岭新分布的苔类有78种。根据种数,秦岭地区苔类的优势科为光萼苔科(34种),其次为耳叶苔科(23种),裂叶苔科(23种)和羽苔科(19种)。 通过对这些种地理成分的统计,发现秦岭苔类的地理成分以北温带成分为主,占35.05%;其次是东亚成分占到31.78%,这两种地理成分在秦岭占了很大比例,高达66.83%。热带成分相对较少,有22种,占到10.29%。对于苔类来说,中国特有成分在秦岭地区较多,已知有34种,占到15.89%。说明秦岭地区苔类地理成分以温带为主,热带成分占少量比例,且秦岭地区的特有性也比较高。 文章第二部分是对中国剪叶苔属Herbertus S. Gray的分类学修订。剪叶苔属隶属于剪叶苔科,是一个古老而自然的类群,广泛分布于热带和南北温带地区。剪叶苔属植物由于其叶横生或近于横生,侧叶2裂,腹叶2裂或部分不对称3裂,并具假肋,叶细胞具大的三角体而明显区别于苔类的其它属。虽然这个属的概念比较清楚,但在属内种间的划分上存在较大的问题,是苔类中分类较混乱的一个类群。剪叶苔属种的概念多基于叶片形态,包括裂瓣的顶端细胞和假肋的形态及叶基盘边缘附属物的形态。但这些形态特征具很大的可塑性,性状不稳定,造成该属种的概念很模糊。目前全世界剪叶苔属约100余种。中国剪叶苔属的种类尚不确定,《中国苔藓志》中报道了中国有25种l亚种,但Juslen在2006年对亚洲剪叶苔属的修订中,提到中国分布的仅有6种。二者的研究中都存在有一些疏漏和不足之处,对有些种还有争议;且他们的研究中引证的标本都很少,不能全面反映中国剪叶苔属的种类和分布情况。 本研究着手于中国的剪叶苔属,从模式标本入手,从模式标本入手,结合对前人文献中引证标本的查阅,并检视了全国各大标本馆收藏的大量该属的普通标本,对于分类归并上有争议的种,采用扫描电镜和分子生物学的手段进行实验性的研究,对中国的剪叶苔属进行一个全面系统的分类学修订。期望通过本研究,明确中国剪叶苔属的种类和分布情况,为东亚乃至世界剪叶苔属的分类修订提供一份翔实的资料。共查阅了剪叶苔属26个种的模式标本,并检视了中科院北京植物研究所、华南植物园和深圳仙湖植物园馆藏的大量该属植物标本,约600余份。 通过本研究,提出2个新异名:将H. buchii Juslén和H. longispinus var calvs Massalongo处理为H. dicranus (Taylor) Trevis.;将樱井剪叶苔H. sakuraii (Warnst.) S. Hatt.(原并入H. dicranus)和H. minimus Horik.(原并入H. dicranus)重新提出;发现1个中国新分布:H. setigerus (Steph.) H. A. Mill.;确认中国的剪叶苔属17种1亚种:剪叶苔H. aduncus (Dicks.) Gray,剪叶苔纤细亚种H. aduncus subsp. tenuis (A. Evans) H. A. Mill.et E. B. Bohrer,H. armitanus (Steph.) H. A. Mill.,南亚剪叶苔H. ceylanicus (Steph.) Abeyw.,长角剪叶苔H. dicranus (Taylor) Trevis.,高氏剪叶苔H. gaochienii Fu,广东剪叶苔H. guangdongii P.J. Lin & Piippo,卵叶剪叶苔H. herpocladioides Scott. et. Miller,红枝剪叶苔H. huerlimannii Miller,细指剪叶苔H. kurzii (Steph.) H. A. Mill.,长肋剪叶苔H. longifissus Steph.,长刺剪叶苔H. longispinus Jack et Steph.,H. minimus Horik.,长茎剪叶苔H. parisii (Steph.) H. A. Mill.,多枝剪叶苔H. ramosus (Steph.) H. A. Mill.,樱井剪叶苔H. sakuraii (Warnst.) S. Hatt.,短叶剪叶苔H. sendtneri (Nees) Lindb.和H. setigerus (Steph.) H. A. Mill.。本研究还在扫描电镜下观察了H. armitanus、长角剪叶苔H. dicranus和多枝剪叶苔H. ramosus的孢子形态。对于剪叶苔属的修订,还需要更多模式标本的借阅,随着研究深入,剪叶苔属的种类可能会有大量的减少,中国剪叶苔属的种类也将会有一定的减少。
Resumo:
Aims: Repeated exposure to heroin, a typical opiate, causes neuronal adaptation and may result in anatomical changes in specific brain regions, particularly the frontal and limbic cortices. The volume changes of gray matter (GM) of these brain regions, ho
Resumo:
Four microsatellites were used to examine the genetic variability of the spawning stocks of Chinese sturgeon, Acipenser sinensis, from the Yangtze River sampled over a 3-year period (1999-2001). Within 60 individuals, a total of 28 alleles were detected over four polymorphic microsatellite loci. The number of alleles per locus ranged from 4 to 15, with an average allele number of 7. The number of genotypes per locus ranged from 6 to 41. The genetic diversity of four microsatellite loci varied from 0.34 to 0.67, with an average value of 0.54. For the four microsatellite loci, the deviation from the Hardy-Weinberg equilibrium was mainly due to null alleles. The mean number of alleles per locus and the mean heterozygosity were lower than the average values known for anadromous fishes. Fish were clustered according to their microsatellite characteristics using an unsupervised 'Artificial Neural Networks' method entitled 'Self-organizing Map'. The results revealed no significant genetic differentiation considering genetic distance among samples collected during different years. Lack of heterogeneity among different annual groups of spawning stocks was explained by the complex age structure (from 8 to 27 years for males and 12 to 35 years for females) of Chinese sturgeon, leading to formulate an hypothesis about the maintenance of genetic diversity and stability in long-lived animals.
Resumo:
Both commercial and scientific applications often need to transform color images into gray-scale images, e. g., to reduce the publication cost in printing color images or to help color blind people see visual cues of color images. However, conventional color to gray algorithms are not ready for practical applications because they encounter the following problems: 1) Visual cues are not well defined so it is unclear how to preserve important cues in the transformed gray-scale images; 2) some algorithms have extremely high time cost for computation; and 3) some require human-computer interactions to have a reasonable transformation. To solve or at least reduce these problems, we propose a new algorithm based on a probabilistic graphical model with the assumption that the image is defined over a Markov random field. Thus, color to gray procedure can be regarded as a labeling process to preserve the newly well-defined visual cues of a color image in the transformed gray-scale image. Visual cues are measurements that can be extracted from a color image by a perceiver. They indicate the state of some properties of the image that the perceiver is interested in perceiving. Different people may perceive different cues from the same color image and three cues are defined in this paper, namely, color spatial consistency, image structure information, and color channel perception priority. We cast color to gray as a visual cue preservation procedure based on a probabilistic graphical model and optimize the model based on an integral minimization problem. We apply the new algorithm to both natural color images and artificial pictures, and demonstrate that the proposed approach outperforms representative conventional algorithms in terms of effectiveness and efficiency. In addition, it requires no human-computer interactions.