用关联矩阵求解物品分区

由图的关联矩阵,通过逐次极大全1子矩阵序列或元素全为1的极大对角块矩阵,给出了物品分区的代数求法,并进行了理论证明．     

弱酸混合酸滴定准确度的理论探讨

本文用严格的数学方法从理论上系统探讨了弱酸混合酸的分步滴定问题和总酸量的滴定问题,提出了在允许误差ε=0.2％、突跃范围ΔpH=0.6条件下的混合酸准确滴定判据。     

云锦杜鹃幼树光合特性及其与生态因子的关系

自然条件下,对云锦杜鹃光合作用日进程进行了测试,研究结果表明：(1)夏季晴天云锦杜鹃幼树叶片净光合速率日进程曲线为“双峰”型,胞间CO2浓度的日进程基本与净光合速率相反,中午胞间CO2浓度增高表明净光合速率午问降低主要受非气孔限制因素的影响;(2)应用逐步多元回归方法,得到云锦杜鹃净光合速率日变化的最优方程为：Y=28．3043 0．0028X1-0．2821X2-0．8538X4 0．0414X5。偏相关分析和通径分析表明,光合有效辐射、空气CO2浓度、气温和叶温与净光合速率的日变化有着密切关系,是影响净光合速率的直接主要因子。     

Studies on property of sample size and different traits for core collections based on genotypic values of cotton

Studies were conducted on specific core collections constructed on the basis of different traits and sample size by the method of stepwise cluster with three sampling strategies based on genotypic values of cotton. A total 21 traits (11 agronomy traits, 5 fiber traits and 5 seed traits) were used to construct main core collections. Specific core collections, as representative of the initial collection, were constructed by agronomy, fiber or seed trait, respectively. As compared with the main core collection, specific core collections tended to have similar property for maintaining genetic diversity of agronomy, seed or fiber traits. Core collections developed by about sample size of 17% (P ₂=0.17) and 24% with three sampling strategies could be quite representative of the initial collection. Project(No 39470377) supported by NSFC     

农牧交错带牧区土地利用方式变化过程及其社会发展驱动机制研究——以四子王旗为例

一个区域的土地利用与土地覆被变化不但受制于自然因素,而且社会因素对其也产生重大影响。近十年来四子王旗6.9%的土地利用方式发生了变化。旱地、天然草地和未成林造林地三者变化面积占四子王旗土地变化面积的96.67%。对1997-2002年的土地变化流向进行了分析,旱地和天然草地主要流向了未成林造林地。研究结果表明：经济因素、农牧业发展因素和政策因素是四子王旗土地利用方式变化的主要驱动因素。     

女大学生内脏脂肪面积逐步回归预测模型研究

目的：测量女大学生的内脏脂肪面积,并在此基础上建立预测方程。方法：对丽水学院62名女大学生进行身体形态指标和内脏脂肪面积的测量。结果：以形态指标为自变量,以女大学生内脏脂肪面积为因变量,进行逐步回归分析。结论：选出预测女大学生内脏脂肪面积的两个回归模型为y^=-130.624＋2.316×腰围,y^=-53.867＋2.482×腰围-0.539×身高。     

Effect of the scale of quantitative trait data on the representativeness of a cotton germplasm sub-core collection

A cotton germplasm collection with data for 20 quantitative traits was used to investigate the effect of the scale of quantitative trait data on the representativeness of plant sub-core collections.The relationship between the representativeness of a sub-core collection and two influencing factors,the number of traits and the sampling percentage,was studied.A mixed linear model approach was used to eliminate environmental errors and predict genotypic values of accessions.Sub-core collections were constructed using a least distance stepwise sampling(LDSS) method combining standardized Euclidean distance and an unweighted pair-group method with arithmetic means(UPGMA) cluster method.The mean difference percentage(MD),variance difference percentage(VD),coincidence rate of range(CR),and variable rate of coefficient of variation(VR) served as evaluation parameters.Monte Carlo simulation was conducted to study the relationship among the number of traits,the sampling percentage,and the four evaluation parameters.The results showed that the representativeness of a sub-core collection was affected greatly by the number of traits and the sampling percentage,and that these two influencing factors were closely connected.Increasing the number of traits improved the representativeness of a sub-core collection when the data of genotypic values were used.The change in the genetic diversity of sub-core collections with different sampling percentages showed a linear tendency when the number of traits was small,and a logarithmic tendency when the number of traits was large.However,the change in the genetic diversity of sub-core collections with different numbers of traits always showed a strong logarithmic tendency when the sampling percentage was changing.A CR threshold method based on Monte Carlo simulation is proposed to determine the rational number of traits for a relevant sampling percentage of a sub-core collection.     

二次多项式逐步回归在狭叶仙鹤藓生长研究中的应用

应用二次多项式逐步回归方法构建了不同营养元素对狭叶仙鹤藓的植株高度和植株数量的影响方程,并定量研究了不同元素对狭叶仙鹤藓的生长情况影响.结果表明,N和Ca2＋和适量的Mg2＋能够在狭叶仙鹤藓的生长中起到促进作用;而K＋对狭叶仙鹤藓的植株高度会产生不利影响,适量的K＋能够促进狭叶仙鹤藓的植株数量.     

Constructive Criticisms of Methodological and Editorial Practices

Thompson (1999a and elsewhere) has taken strong positions on a variety of methodological issues. In this article, the authors critique some of those positions and provide alternative views for each.     

中医传统功法训练与大学生体质健康的关联研究

运用文献资料法、实验法和数理统计法对大学生体质健康影响结果进行分析和研究。结论:中医传统功法长期训练对大学生的心率、呼吸都有重要影响,能够提高肌肉等组织的活动功能,特别是手指、手臂等的力量,训练之后影响体质健康测试总分的主要项目是握力、坐位体前屈和肺活量体重指数评价项目。中医传统功法训练对提高台阶试验和立定跳远项目的成绩没有显著性影响。运用无量纲化处理后的测试数据,经逐步回归分析法综合评价大学生体质健康测试结果具有实际意义。