用夹逼法求方程的近似解

论证了用夹逼法求方程近似解的一种新的方法，并通过举例对方法的应用加以说明。     

数据非平衡性对试验分析结果的影响

利用蒙特卡罗(MonteCarlo)模拟考察了随机区组设计、裂区设计和条区设计因数据缺失形成的数据非平衡性对试验分析结果的影响。结果表明,数据非平衡性可导致方差组分估计的精准度降低、固定效应误差的偏低估计以及固定效应测验一类统计错误率的增大。缺失数据越多,这一现象表现越明显。数据缺失对随机区组设计分析精准度的影响小,而对裂区和条区设计分析精准度的影响大。     

赤水市水土保持生态修复工程生态效益评价研究

以赤水市水土保持生态修复工程为依托,对水土保持生态修复效益评价方法进行了探索,建立了开展水土保持生态修复工程生态效益调查、评价的基本技术与方法。评价中坚持了客观性和系统性原则,以植被覆盖度,生物多样性,群落生物量,土壤有机质,N,P,K含量,表土侵蚀和泥沙含量变化为评价指标,通过野外定位监测获取水土流失、植被覆盖度、生物量等数据,然后采用定量方法评价工程实施产生的生态效益。结果显示,赤水市水土保持生态修复工程的实施,取得了巨大的生态效益,植被覆盖度、生物多样性、生物量、土壤肥力等都有所增加,而土壤侵蚀、泥沙含量等则大幅减少。     

Camera trap, line transect census and track surveys: a comparative evaluation

Rapid faunal assessments can use different methods depending on environmental conditions and costs. To compare the efficiency of three methods in detecting species richness and abundance, we tested them in the grasslands of Emas National Park, central Brazil. Track census was the most effective method for detecting richness, followed by camera-trapping and direct faunal counts. Track census reached an asymptote for number of species after only 12 days, but all methods converged on similar estimates of species richness after around 30 days. There was no significant spatial correlation for species richness or total abundance, between camera trap and tracks, across the 29 samples distributed in the park. However, for some species, abundance showed significant spatial correlation between methods. Also, these rates were significantly correlated across species and the spatial correlation between methods was significantly associated with log-transformed body mass across species. We conclude that, despite the high initial costs for camera-trapping, this method is the most appropriate for mammal inventory in all environmental conditions, allowing a rapid assessment of wildlife conservation status.     

SCHOOLFIELD模型参数的初值估计及最优化拟合

提出了Schoolfield模型参数初值估算的一种新方法,并介绍了用Marquardt法最优化拟合该模型的算法。文中用侧多食跗线螨在不同温度下发育速率的实验数据作实例,给出了计算初值的具体步骤,并进行了曲线的拟合。结果表明,与其他方法相比,用本文的方法计算的参数初值相对误差之和最小。拟合效果经x~2检验显著适合。     

Excel环境下土木工程投标报价计算方法--以公路工程为例

利用 Excel软件的电子表格制作、数据处理和运算功能及良好的人机交互对话界面 ,结合某高速公路投标报价 ,介绍了 Excel环境下的计算方法。结果表明 ,该方法能快速、准确、完整地实现工程概预算。     

一阶非线性椭圆型复方程的非线性P-H边值问题

本文运用与 Newton迭代相结合的嵌入方法,讨论了一类在2n+1个附加条件下的一般非线性椭圆型复方程的非线性Riemann-Hilbert边值问题.我们在C~(1+α)(D)上得到了解的存在性与唯一性,并给出了近似解的误差估计式。     

Genetic analysis of pod quality characteristics in vegetable cowpea (Vigna unguiculata L. Walp.)

A preliminary study of consumer preferences for pod characteristics in vegetable cowpea showed a general preference for greener, longer, fleshier pods that are less seedy. Methods of quantitatively assessing these traits were developed and used in understanding the inheritance of pod quality traits. Combining ability analysis, involving a 6 × 6 diallel mating design, showed that GCA effects were predominant for all pod characteristics. The additive effects were especially high for pod seediness. The dominance effect was, nevertheless, significant for all the characters. The dominance effects were unidirectional in the case of pod wall thickness and were in the direction of the thin walled parent. Dominance was ambidirectional for the other characteristics investigated. The study showed that it is relatively easy to improve these characters by carefully selecting the parents in hybridisation programmes.     

家蚕茧质性状广义遗传分析

采用广义遗传模型分析得知，全茧量、蛹重的性连锁效应作用强度达５０％左右，加性效应与显性效应的作用强度相近，为１５％左右；茧层量、丝素量主要受加性效应控制，达５０％左右，显性效应为２５％左右，性连锁效应较弱，为５％左右；茧层率加性效应与性连锁效应的作用具同等强度，为３０％多；显性效应作用较弱，为１０％左右．母体效应在５个性状中的作用较弱，基因与环境互作效应对５个性状作用形式相类似．其中基因加性及显性与环境互作两项效应的作用略强．由本模型所得剩余机误方差很小，仅为５％左右，说明本模型比较合理．因此，在此基础上，对各个供试品种的遗传效应预测值的分析比较可信