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1.
多种天敌控制多种害虫的模糊数学模型 总被引:2,自引:0,他引:2
从生态经济学的原理出发,利用模糊集理论,探讨如何评价天敌控制多种害虫的为害作用,提出了多种天敌控制多种害虫的模糊数学模型。同时又得到了天敌对害虫的控制能力C,影响率G,影响强度H,及权数ω(x)的计算公式,以及在天敌作用下安全度的讨论与分析。 相似文献
2.
E. Nieman 《BioControl》1991,36(1):77-86
The mothMimorista pulchellalis was monitored over 2 years after liberation in a jointed cactus (Opuntia aurantiaca) infestation in South Africa. Moth and cactus densities were estimated using a system of randomly-assigned quadrats and the
impact of the moth on the cactus population quantified. Moths appeared adapted to survive on the etiolated form of jointed
cactus plants, killing approximately 1% of the increment in small plants annually. Large plants were also attacked but damage
was negligible. The moths occurred in low numbers throughout the study period and generally went through 3 generations in
a year.
Résumé La pyraleMimorista pulchellalis a été surveillée durant les deux années qui suivirent sa libération dans une infestation de figuier de Barbarie en Afrique du Sud. Les densités de pyrale et de cactus ont été estimées en utilisant un système de quadrats distribués au hasard et l'impact de la pyrale sur la population de cactus a été quantifiée. Les pyrales semblaient adaptées à survivre sur la forme étiolée des plants de cactus tuant approximativement 1% de l'accroissement annuel des petits plants. Les gros plants étaient aussi attaqués, mais les dégats étaient négligeables. La pyrale existait en faibles nombres durant toute la période d'étude et elle présentait généralement 3 générations par an.相似文献
3.
基于各学科信息作出安全性、有效性和质量可控性方面的综合评价是新药研究评价的灵魂,是一个多学科、多组织参与的综合决策过程。根据新药评价研究的实际工作经验,介绍一个新药临床试验综合评价的逻辑性、结构性的工作思考模式,有助于将不同专业的技术信息和技术结论有机整合,作出科学决策。 相似文献
4.
P. Loslever J. Schiro F. Gabrielli P. Pudlo 《Computer methods in biomechanics and biomedical engineering》2017,20(10):1038-1047
The purpose of this article is to compare Principal Component Analysis (PCA) and a much less used method, i.e. MCA (Multiple Correspondence Analysis) with data being first changed into membership values to fuzzy space windows. For such a comparison, data from an experimental study about turning the steering wheel is used. In a didactic perspective, this article only considers one multidimensional signal with 5 components: 3 linked to the steering wheel angle and hand positions and 2 to hand effort variables. A discussion weighs out the pros and the cons of both methods with criteria such as the possibility to show complex relational phenomena, the analysis/computing time or the information loss inherent to the averaging stage (in the perspective to analyze several hundreds of large multidimensional signals). 相似文献
5.
A simple procedure is described for the determination of the photosensitizing potency of drugs, using three leukemic cell lines, two of lymphocytic origin, L1210 and P388 and one of erythroid type, Friend-745. The procedure allows one to investigate several aspects of the photosensitization properties of tested compounds such as cellular localization and direct (trypan blue exclusion) or delayed (clonogenicity) photomediated toxicities.The method was assessed using crude hematoporphyrin derivative (HPD) as well as dihematoporphyrin ether (DHE) or commercially available Photofrin II. Results were compared to those obtained with normal cells, e.g spleen lymphocytes and erythropoietic stem cells (CFU-e), and discussed in the light of the relative response of normal versus transformed cells.Abbreviations DHE
Dihematoporphyrin Ether
- FCS
Fetal Calf Serum
- HPD
Hematoporphyrin Derivative
- PDT
Photodynamic Therapy 相似文献
6.
A firm, mobile, oblong mass was discovered as an incidental finding in the stomach of a chimpanzee (Pan troglodytes) during routine surgery. It was removed and determined to be a trichobezoar. 相似文献
7.
8.
Patrick T. Curry Terry Ziemer Gerhard Van der Horst Warren Burgess Monte Straley Robert W. Atherton Robert M. Kitchin 《Molecular reproduction and development》1989,22(1):27-36
Ejaculated sperm from the domestic ferret (Mustela putorius furo) and the black-footed ferret (Mustela nigripes) were compared for differences in morphological abnormalities and argentophilic protein distribution. Thawed domestic ferret sperm was also compared to fresh sperm to determine whether there were any effects on cell morphology due to cryopreservation. There were statistically significant differences between the two species of ferret in two of the categories scored. The domestic ferret had a higher frequency of cells that were bent in the midpiece and in the principal piece, and a higher frequency of headless and tailless cells when compared to the black-footed ferret. There were no statistically significant differences in cell morphology between the fresh and cryopreserved ejaculates of the domestic ferret employing a standard egg yolk cryoextender. Silver nitrate staining distribution was different between the two species in both the head and tail region. 相似文献
9.
Fertilizers labelled with 32P were used to measure amounts of phosphorus, Ps and PF, taken up by Lolium perenne from available soil P and from P fertilizer respectively, when applied at a rate of 66 mg P·(kg soil–1) in greenhouse experiments. The quantity Ps of phosphorus taken up from soil in the presence of P fertilizer was compared to the quantity Po taken up from soil without P fertilizer. The quantity (Ps–Po) is positive for low Po values, i.e. in soils poor in available phosphorus, but is negative for high Po values indicating that an input of P fertilizer can induce a decrease in the utilization of available soil phosphorus. Moreover, for a given soil, the quantity (Ps–Po) depends on the chemical form of the fertilizer. The standard method of evaluation of P fertilizer efficiency is based on the assumption that Ps=Po, but Ps can differ from Po. This result can explain the contradictory data published from field experiments about the efficiency of the various P fertilizers. 相似文献
10.
.熊治廷;.黄德世;.王徽勤;.孙祥钟 《武汉植物学研究》1990,8(1):47-52
用R聚类分析和主分量分析,定量研究了湖北菱科5种8变种37个形态和生态性状的变异及分类学价值。结果表明,植物体大小变异是形态演化的主要方向之一。形态演化的同时,也发生生态分化。除少数性状例外,形态演化与生态分化在相当程度上是独立的。 相似文献