一类含单奇点的极限环的三次系统

证明具体三次系统x=y-εy~3,y=x(1-x~2)+(α-x~2)y,当α≥1或0<α≤1/3时,在区域|y|<1/ε~(1/2)内无含单奇点的极限环,这里ε>0.     

一类KOLMOGOROV系统的极限环

关于两种群互相作用的Kolmogorov模型 x=xF_1(x,y), y=yF_2(x,y),文〔1〕根据生态意义对F_1、F_2给出较多限制条件下作过研究,由于现实中总结出的模型归结到F_1、F_2为x和y的多项式的形式不少〔2,3〕,本文讨论一类Kolmogorov系统x=x(a_0+a_1x-a_3x~2+a_2y+a_4xy),y=y(x-1) (1)极限环的存在性和唯一性,其中x和y分别表示两种群的密度,参数a_0>o,a_3>o,a_1、a_2、a_4不定号,它们各表示一定的生态意义,随不同的取值范围而反映两种群的不同作用〔1〕。     

一类被开发的捕食系统的定性分析

讨论了一类食饵种群被开发的两种群捕食系统: dx/dt=x(a0+a1x-a2x2-a3y3)-h0, dy/dt=y(x-1)其中a0>0,a2>0,a3>0,h0>0,a1不定号.文中主要讨论了系统平衡点的行为以及系统的稳定性.用Pioncare切性曲线法及Dulac函数法讨论闭轨不存在的充分条件;用Hopf分支方法及张芷芬唯一性定理证明了极限环的存在性与唯一性.同时对相应结论的生态学意义给予了说明.     

生化反应中一类三次系统的极限环

研究生化反应中一类三次系统：dx/dt=-x-Ф1（x）＋yФ2（x）,dy/dt=a0＋Ф1（x）-yФ2（x）其中Ф1（x）=Ax^3＋ax^2＋bx＋B,Ф2（x）=cx^2＋dx＋e．较完整地解决了该系统极限环的存在性,唯一性与不存在性等问题．     

一类Holling功能性反应模型极限环的唯一性

考虑功能性反应的捕食-食饵模型这里y表示捕食者种群的密度,当a-（22）≠0时它具有线性密度制约,x表示食饵种群密度,当φ（x）≡ax/（1＋ωx）时称（1）为第二类功能性反应模型．文〔1〕研究了捕食者没有密度制约（对应于a_（22）=0）、食饵具有线性密度制约(对应于g（x）=b_1-a_(11)x）的Ⅱ类功能性反应模型（1）,得到了极限环存在性及唯一性的完整结论．最近文〔2〕在a_(22)≠O的条件下讨论了系统(1),得到了极限环的存在性与不存在性等福建省自然科学基金和国家自然科学基金资助项目（19371069号）．本文第一作者现为浙江大学访问学…     

功能反应函数为kxθ的食饵-捕食系统的定性分析

研究了具功能反应的一类食饵-捕食系统：x=x（a—bx^m-h（x））（z））-kx^θY,y=Y（-e＋dkx^θ）（0〈θ≤1）并得到了系统在正平衡点外围的极限环的不存在性与存在唯一性的相关条件．     

一类具功能反应的食饵-捕食者模型的定性分析

对一类具功能反应的食饵-捕食者模型：x=xg（x）-yφ（x）,y=y（-d＋eφ（x））进行了研究,讨论了该系统平衡点的性态,系统无环的充分条件及正平衡点外围存在唯一稳定极限环的条件．     

一类具功能反应的食饵-捕食者两种群模型的定性分析

对具功能反应的食饵-捕食者两种群模型x=xg(x)-y( )(x),y=y(-d+e( )(x)).在g(x)=α-baα,( )(x)=cxα(a,b,c＞0,1/2≤α＜1)且α使函数f(x)=x1/a在(-∞,+∞)上为偶函数时进行了研究,讨论了该系统平衡点的稳定性态,系统无环的充分条件以及在正平衡点外围存在惟一稳定极限环的条件.     

豆天蛾田间饲养量及效益研究

通过对豆天蛾在田间笼罩条件下的饲养调查观察 ,测定出其幼虫食叶量、食叶率 ,从而计算出每平方米豆田的理论养虫量 ,实际适宜养虫量及对大豆产量损失的影响。笼罩条件养虫量 (x)与食叶率(y1)回归方程 :^y1=2 2 0 + 2 4 1x± 2 874 9,r1=0 9971 ;笼罩条件养虫量 (x)与产量损失率 (y2 )回归方程 :^y2 =1 5 7+ 0 4 2 5x± 0 6 837,r2 =0 994 6 ;笼罩条件养虫量 (x)与结荚损失率 (y3 )回归方程 :^y3 =1 5 7+ 0 33x± 1 785 4 ,r3 =0 94 6 8 。在幼虫饲养量为 1 0～ 1 5头 m2 时 ,综合效益比一般豆田每 6 6 7m2增收 4 73 6元以上。     

3种甘草属植物的核型研究

用光学显微镜观察了豆科（Leguminosae）甘草属（Glycyrrhiza）3种荒漠植物的染色体,研究结果表明,3种植物的体细胞染色体数目2n=16,核型公式分别为：刺果甘草（G.pallidiflara）k(2n)=2x=16=4M+8m+4sm,光果甘草（G.glabra）k(2n)=2x=16=10M+6m,胀果某草（G.inflata）k(2n)=2x=16=6M+6m+4sm。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

棉铃虫钙粘蛋白N端多肽多克隆抗体制备及对Bt抗性的初步检测

用重组表达的棉铃虫Helicoverpa armigera(Hübner)中肠钙粘蛋白N端多肽片段制备兔多克隆抗体,并利用其对Bt抗性进行鉴定。通过RT-PCR方法对棉铃虫中肠钙粘蛋白N端多肽的基因片段Cad285进行PCR扩增,将其克隆到pET-30a原核表达载体中,在大肠杆菌BL21(DE3)中经IPTG诱导表达,得到35ku的重组融和蛋白,融合表达的包涵体经过变性、Ni-NTA柱亲和纯化、复性等方法处理包涵体,获得可溶性纯化蛋白,用纯化后蛋白免疫新西兰兔制备多克隆抗体,ELISA检测其效价高于1∶16000;利用最终获得的多克隆抗体对室内纯合Bt抗/感品系的棉铃虫中肠钙粘蛋白进行Western blot分析,结果显示敏感和抗性品系之间有明显差异,表明其能够应用对Bt抗性进行初步检测。     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

医疗机构合理用药评价模型的构建研究

目的 针对医疗机构的合理用药水平进行评价研究。方法 根据医疗机构合理用药的具体要求,构建医疗机构合理用药评价指标体系,采用基于模糊群决策的方法和多指标评价分析法构建医疗机构合理用药评价模型。结果 构建了基于模糊群决策的医疗机构合理用药评价模型,并通过实例分析证明了评价模型的可行性。结论 建立的基于模糊群决策的医疗机构合理用药评价模型能够对医疗机构的合理用药水平进行科学评价,为提高医疗机构合理用药水平奠定基础。     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

Time of detection of recessive genes: effects of system of mating and number of examined individuals

Summary Anthers were cultured from two sets of seven lines of hexaploid wheat (Triticum aestivum L.) with different cytoplasms, the euplasmic nucleus donors, Siete Cerros 66 and Penjamo 62, as well as their six alloplasmic lines derived from wild relative species of the genera Triticum and Aegilops. Significant cytoplasmic and nuclear effects but no cytoplasmic-nuclear interaction were found for embryogenic anther response, with the best performance of Penjamo 62 in Ae. kotschyi cytoplasm. Plant regeneration was not affected significantly by the cytoplasmic background of the lines cultured. The possible genetic implications of the observed cytoplasmic and nuclear influences on the in vitro haploid induction of wheat are discussed.     

青蒿素生物合成机理研究现状

本文总结了目前有关青蒿素生物合成机理方面的研究,主要包括青蒿素生物合成中生理因子的影响,青蒿素生物合成中间体及前体,青蒿素生物合成细胞定位等。指出了存在的一些问题及今后的研究发展前景。     

Scales of spatial patterns of distribution of intertidal invertebrates

Few comparative studies of spatial patterns at different scales have examined several species in the same habitat or the same species over a range of habitats. Therefore, variability in patterns among species or among habitats has seldom been documented. This study quantifies spatial patterns of a suite of intertidal snails and a species of barnacle using a range of statistical techniques. Variability in densities was quantified from the scale of adjacent quadrats (over a distance of centimeters) to tens of kilometers. Significant differences in abundances occurred primarily at two spatial scales. Small-scale differences were found at the scales of centimeters or 1–2 m and, for many species on many shores, these accounted for most of the variability in abundances from place to place. These are likely to be determined by behavioural responses to small-scale patches of microhabitat. Large-scale differences in abundance were also found in most species at the scale of hundreds of meters alongshore. These are likely to be due to variation in recruitment (and/or mortality) because of limited dispersal by adults of these species. There was little or no additional variation among shores, separated by tens of kilometers, than was shown among patches of shore separated by hundreds of meters. Identification of the scale(s) at which significant differences in abundance are found focus attention on the processes (and the scales at which these processes operate) that influence patterns of distribution and abundance. Some of the advantages and disadvantages of various procedures are discussed.