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两色绿刺蛾幼虫空间分布型 总被引:1,自引:1,他引:0
应用聚集度指标法、回归分析法、零频率方法对两色绿刺蛾幼虫在毛竹林间的分布型进行测定。结果表明,两色绿刺蛾幼虫在竹林中呈聚集分布,分布的基本成分为个体群。用零频率方法分析得,两色绿刺蛾幼虫种群类型为聚集度零频率制约型,并确定了林间调查的理论抽样数和简单序贯抽样分析表。 相似文献
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根据14丘稻田稻茎毛眼水蝇幼虫调查资料.对其幼虫分布型进行了分析。结果表明;用I、CAm/m、Iσ四种聚集指标法测定,64.3%的田块呈随机分布.28.4%为均匀分布.7.3%为聚集分布。用Iwao平均拥挤度和Taylor幂法则测定.其田间分布型符合随机分布。用频次拟合法测验,50%的田块同时符合渡松、奈曼和负二项分布三种分布型;35.7%的田块同时符合2种分布型。根据该虫田间分布型的特点.制定了相应的序贯抽样技术。 相似文献
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竹小蜂幼虫空间分布型及抽样技术研究 总被引:6,自引:3,他引:3
竹小蜂幼虫空间分布型属于负二项分布;聚集度各指标测定结果表明,幼虫是聚集分布;经测定M^*=6.2836 0.3028^ˉx,屑于聚集分布。并用刀切法和F偏离度检验法对M^*进行了估计和检验测定为聚集分布。中分析并计算了林间调查的理论抽样数和序贯抽样决策,为今后该虫林间调查与防治提供了科学的依据。 相似文献
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红棕象甲幼虫空间格局研究 总被引:1,自引:0,他引:1
【背景】红棕象甲是外来危险I生有害生物,近十年来在我国南方严重危害棕榈科植物。[方法】为了确定其调查抽样方法、准确获得虫情,应用聚集度指标法和回归模型分析法等,对红棕象甲幼虫的空间格局进行了研究。【结果】在lwao模型中,α=0.4208〉0,β=1.5133〉1,这说明了红棕象甲幼虫的种群空间格局的分布图式为聚集型;用马占山重新解释的Taylor幂法则分析表明,红棕象甲幼虫的空间格局归属于聚集型,个体之间相互吸引。【结论与意义】红棕象甲幼虫在林内呈聚集型分布,分布的基本成分为个体群;运用1wao法确定了林间最适理论抽样数和序贯抽样模型,为该虫的监测与防治提供了依据。 相似文献
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Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis
It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis. 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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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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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