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林麝和马麝分类的判别分析 总被引:5,自引:3,他引:2
林麝Moschus berezovskii和马麝M.sifanicus是两种经济价值很高的药用动物。目前主要根据外形及身体量度的方式进行分类。作者利用其头骨的量度进行多元统计的判别分析方法,对两种麝的分类进行了探索。 相似文献
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本文讨论增长曲模型的回归参数B的影响分析,导出了度量影响大小的似然距离量度LD,并分析了LD与广义Cook距离的联系,最后的实例应用说明了似然距离统计量度量增长曲线模型的影响点是有效的。 相似文献
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《四川动物》2017,(4)
最近,遗传学研究证明了越南三线闭壳龟Cuoro cyclornata的有效性,并表明这个种内还存在第3个尚未描述的亚种,这个亚种也能从体色和形态量度上与以前认定的2个亚种相区分。同时,也证明中国三线闭壳龟C.trifasciata有一个来自中国海南岛在遗传学上存在歧化的种群。此现象也存在于金头闭壳龟C.aurocapitata,很久以来就发现该种有一个在体色量度上明显不同的种群,并得到了微卫星标记和形态学证据的支持。以上两种方法都显示了中国三线闭壳龟、越南三线闭壳龟和尚未描述的亚种之间的区别。为此,本文将这3个种群分别描述为新亚种C.cyclornata annamitica,C.trifasciata luteocephala和C.aurocapitata dabieshani。 相似文献
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Profiles of SARS-CoV-2 RNA and Antibodies in Inpatients with COVID-19 not Related with Clinical Manifestation: A Single Centre Study 下载免费PDF全文
Zhao Li Gao Ruqin Lu Roujian Wang Huijuan Deng Yao Niu Peihua Jiang Fachun Huang Baoying Liang Jiwei Jia Jing Zhang Feng Wang Wenling Wu Guizhen Tan Wenjie 《中国病毒学》2021,36(5):1088-1092
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Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme
responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare
the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show
that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by
distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of
demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least
one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of
the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable
potent antiproliferative synthetic drugs. 相似文献
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正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases 相似文献
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RICHARD E. NORRIS 《Botanical journal of the Linnean Society. Linnean Society of London》1991,106(1):1-40
Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera. 相似文献
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JOAN VALUÈS MONTSERRAT TORRELL NÚRIA GARCIA JACAS 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):399-407
Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted. 相似文献
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