流体力学反问题的类型及其应用

反问题的研究是一门前沿学科，这一研究使人们从对自然现象的预测上升到对自然现象的控制。文章从流体力学通用微分方程和工程实践亟等解决的实际问题出发，同时参照其它学科中反问题的提法，将流体力学中的反问题分成参数控制反问题、源项控制反问题，边界条件控制反问题，初始条件控制反问题和形状控制反问题等五类，同时分别2以工程中的实例进行举证。     

Serological reactivity of duck sera to three electrophoretically characterized extracts of Aspergillus

Three different antigens, whole culture, cell sap shaker culture and culture filtrate extracts of Aspergillus were characterized by crossed immunoelectrophoresis. Thirteen to fifteen precipitin lines were produced with their homologous antisera. Application of these extracts to the assay of wild duck sera showed that the whole culture extract was the most sensitive of the three antigens in detecting antibody. Countercurrent immunoelectrophoresis, used with a modified buffer, produced results comparable in sensitivity to immunodiffusion in detecting avian antibody.     

云南不同地点及海拔异色瓢虫鞘翅色斑变异比较

2006年5月至2007年3月,分别在云南香格里拉、东川、元江和昆明进行野外标本采集．对4个地点的异色瓢虫Harmonia axyridis（Pallas）色斑变异进行了研究。结果显示,4个地点的异色瓢虫体色多以黄色为基本色调,鞘翅变化可分为黑底和黄底两大系列,共有43种色斑变异型。香格里拉、东川和昆明等3个地点黑底系色斑变异个体数量小于黄底系个体数量,而在元江则是黑底系个体数量占优势。在不同海拔地带中,异色瓢虫色斑变异出现个体数量最高是中海拔地带。异色瓢虫色斑变异是对生活环境的一种积极适应。图3表2参12     

Identification of genomic regions carrying QTL for agronomic and quality traits in rye (Secale cereale) introgression libraries

Introgression libraries can be used to localize genomic regions carrying quantitative trait loci (QTL). We used this approach to detect QTL regions affecting the per se performance of agronomic and quality traits with two rye (Secale cereale L.) introgression libraries. Our objectives were to detect candidate introgression lines (pre‐ILs) that have a different per se performance than the recurrent parent and to identify the underlying QTL regions. The introgression libraries containing 40 BC₂S₃ lines each were established with marker‐assisted backcrossing from crosses of the heterozygous Iranian primitive rye accession Altevogt 14160 and the elite inbred line L2053‐N. To assess the phenotypic effect of the donor chromosome segments (DCS) the pre‐ILs were evaluated for grain yield, plant height, thousand‐kernel weight, test weight, falling number and protein content in replicated field trials at five locations in Germany over 2 years. In total, 58 significant (P < 0.05) differences between pre‐ILs and L2053‐N were observed in each introgression library. The DCS in pre‐ILs differing from the recurrent parent possess most likely the responsible QTL. Genomic regions carrying favourable QTL alleles were detected for test weight, thousand‐kernel weight and protein content. We conclude that Altevogt 14160 can not only be used to enrich the genetic variation of the restricted hybrid rye gene pools but will also allow the breeder to efficiently detect favourable QTL for marker‐assisted selection.     

Comparison of QTLs mapped in RILs and their test-cross progenies of tropical maize for insect resistance and agronomic traits

Quantitative trait loci (QTL) affecting resistance to south-western corn borer Diatraea grandiosella (SWCB) and sugarcane borer Diatraea saccharalis (SCB) have been identified previously in F_2:3 lines and recombinant inbred lines (RILs) of tropical maize using restriction fragment length polymorphism (RFLP) analyses. Our objective was to determine whether QTLs identified in these generations are also expressed in test crosses (TC) of RILs. A population of 166 TC progenies was developed by crossing RILs from the cross CML131 (susceptible) × CML67 (resistant) with the unrelated, susceptible tester line CML216. Resistance to first-generation SWCB, measured as leaf-feeding damage (LFD) under artificial infestation, and other agronomic traits were evaluated in two environments for the TC progenies and three environments for 183 RILs. The correlation between line per se and TC performance was low for LFD and intermediate for most agronomic traits. Estimates of the genotypic variance and heritabilities were smaller in the TC progenies than in the RILs for all traits. Quantitative trait loci were identified using an RFLP linkage map with 136 loci. For LFD, four QTLs were detected in the TC progenies, of which two were in common with nine QTLs previously mapped in the RILs. Few QTLs for agronomic traits were common to the two types of progeny, because of the low consistency of QTL positions for all traits in RIL and TC progenies, the use of TC progenies should be considered in QTL mapping studies as the first step for marker-assisted selection in hybrid breeding.     

Characterization of QEet.ocs-5A.1, a quantitative trait locus for ear emergence time on wheat chromosome 5AL

QEet.ocs‐5A.1, a quantitative trait locus controlling ear emergence time, has been detected on wheat chromosome 5AL using single chromosome recombinant lines (SCRs) developed from a cross between ‘Chinese Spring’ (CS) (‘Cappelle‐Desprez’ 5A) and CS (Triticum spelta 5A). This locus has little influence on grain yield and its components, and thus has breeding potential for changing ear emergence time without yield reduction. To characterize the phenotypic expression of QEet.ocs.1 and to test its interaction with the Vrn‐A1 gene for vernalization response, six near‐isogenic SCRs differing for these two gene regions were grown together with the parental controls under different vernalization and photoperiod regimes. The T. spelta allele of QEet.ocs.1 accelerated heading time when vernalization and photoperiod were satisfied, demonstrating that the function of this QTL is earliness per se. There was no interaction between Vrn‐A1 and QEet.ocs.1.     

Ecologie des champignons parasites dans le sol—IX. Mesures du potentiel infectieux des sols naturellement infestes de Pythium SP

The technique of estimating inoculum potential of soils infested by Pythium (Bouhot 1975a,b,c) has been applied to more than 600 soil samples. 24 examples of soils, representing the several kinds of results, are presented. In order to improve the linearity of the inoculum density-disease regression, the four mathematical transformations of disease percentages, proposed by Baker (1971), are compared: logarithm of disease percentages, successful infection transformation (LN I/I — ×), log-log and Probit-log. For 80–90% of observed soils the log-log and Probit-log transformations give a straight regression line and allow the differentiation of soils by the use of UPI₅₀ (LD 50 point). The Probit-log appears to be the best to reduce the variance of replications. On the contrary for some soils the inoculum-disease relation is a concave curve different from the ideal curve proposed by Baker. The hypothesis of competition between saprophytic colonization of Pythium and of soil microflora is proposed as an explanation and suggests the opportunity to find a new model for the techniques using plants as bait and organic amendment.     

微量元素硒对肉鸡免疫功能的影响

为了探讨微量元素硒对肉鸡免疫功能的影响，选用20只1日龄的三黄雏鸡随机分为两组，对其中一组进行了35天的饮水补硒的试验。通过对35日龄肉鸡的RBC WBC与白细胞吞噬能力以及抗体效价的测定，结果表明饮用4ppm亚硒酸钠的补硒组肉鸡各项实验指标均不同程度的高于以对照组，提示微量元素硒对肉鸡非特异性及特性免疫功能均具有一定的增强作用，可用于肉鸡的免疫增强剂。     

利用Protel 99se仿真功能求电阻网络的等效电阻

求解电路的电阻是实际电路工作中时常要做的一项工作.传统的办法是采用分析计算的方法.使用protel 99se软件的仿真功能可以求解任意电阻网络的电阻,只需要构建相应的仿真电路并进行简单设置后,运行仿真分析,瞬间即可从仿真结果中得到所求电阻的数值.这在求取复杂电阻网络的电阻时,尤其显得便捷.     

Genetic variation in testcrosses of European maize inbreds for resistance to the European corn borer and relations to line per se performance

The European com borer (ECB) Ostrinia nubilalis H. is a major pest in World maize Zea mays L. production. Objectives of this study were to (1) investigate the genotypic variance and covariance in testcrosses of European flint and dent inbreds for ECB resistance and agronomic traits, and (2) estimate the correlation between line per se and testcross performance for ECB resistance traits. A total of 16 flint and 24 dent inbreds and their testcrosses with two testers from the opposite germplasm pool were evaluated in four and three German environments, respectively. Using artificial infestation with ECB larvae, resistance was assessed by damage rating of stalks, tunnel length in dissected stalks, and relative yield of infested plots compared with protected plots. Yield losses due to ECB damage in testcross hybrids amounted to 40%. Significant genotypic variances between flint and dent lines and high heritabilities were found for damage rating of stalks for both line per se and testcross performance. Heritabilities were low or intermediate for tunnel length and relative grain yield. Correlations between line per se and testcross performance were tight for the damage rating of stalks and moderate for tunnel length and relative yield in both flint and dent germplasm. For damage rating of stalks, per se performance of lines tested in a few environments can be used to predict their testcross performance. In contrast, assessment of testcross performance for tunnel length and relative yield requires evaluating testcrosses with several testers in multi-environment trials.