查询词典 population parameter

In this study the cumulative meta-analysis method was used for ecology study first time and non-parameter effect size was suggested when parametric effect size violates the hypothesis of normal distribution of population and homogeneity of variances.

本研究在对整合分析方法详细阐述的基础上，首次利用该方法进行了全球变化生态学中关于大气平流层臭氧损耗所导致的紫外B区辐射增加对陆地植物生态系统影响的专题的系统研究。

This article first discusses the significance of homogeneity of variance, then studies the general method of transformation for homogeneity of variance on the relation between the data mean and the variance when population distribution is known ,and it uses the Mathematica software to analyse the variety rules between the parameter and the variance in the corresponding transformation.

从方差非齐性数据处理中的变换的必要性入手，根据数据均值与方差之间的关系研究了总体分布已知时的方差齐性变换的一般方法，并利用Mathematica软件分析相应变换中参数与方差之间的图形规律，最后介绍了总体分布未知时的BoxCox变换的一般原理。

We also find two species can coexist only when taking the medium values in some range of parameter,if it is too large or too small only one population can exist or none of them can .

其它的参数不变，而只变化某一个参数的取值，且这一取值变化符合这一参数划分区间，定态会经历这一区间内的多种状态，且会出现临界点，普通渗流与定向渗流类相互转化，且出现两个临界点，两次相转变。

The birth rate of the population is assumed to be a bifurcation parameter and nontrivial nonnegative steady-state solution bifurcated from the trivial steady-state solution has been obtained with the bifurcation theory.

应用分歧理论讨论一类单种群模型的非负定态解，并对该解的稳定性进行了分析。

The validity of simulation results were tested by experiments. Through statistical analysis, the parameter (μ,σ2) of normal distribution function of the maximum load, and tested uniformity of the normal population and the sample were obtained.

在此基础上，随机生成200个典型海底地形，对采矿头截齿最大载荷的分布特性进行研究；应用置信度为0.95的柯尔莫哥洛夫斯米尔诺夫(Kolmogorov-Smirnov)检验验证参数估计所得的正态总体与样本数据的一致性。

Use of similar models in ageing other species, along with periodic validation to ensure that the otolith parameter age relationship has not changed over time, could simplify age data collection for population models.

用耳石参数与年龄的关系来鉴定其他鱼类的年龄，要判断这种关系不会随着时间的变化而改变，这样为种群模型收集相应年龄数据就相当容易了。

In order to improve the variety and universality of the new population in the parameter space, the method of anisomerous crossover is designed.

为提高新生个体的多样性及其在参数空间中的遍布性，提出并设计了不对称交叉的具体方法。

And such methods V/m ratio t-test, negative binomial parameter, index of dispersion, Cassie index, index of clumping, index of mean crowing and index of patchiness are employed to analyse various dominant populations of Heptacodium miconioides community in the Tiantai Mountain in Zhejiang province and distributive patterns of Heptacodium miconioides community in different quadrats, and this paper also examines the intensity of Heptacodium miconioides population in different quadrats by means of stand classes.

摘 要 以浙江省天台山七子花群落为研究对象，采用相邻格子样方法取样数据，应用方差／均值比的t检验法、负二项参数、扩散型指数、Cassie指标、丛生指标、平均拥挤指数和聚块性指数等方法，分析了七子花群落各优势种群以及七子花种群在各样地中的分布格局，并分立木级对七子花种群在不同样地内的集群强度进行了测定。

Spodoptera litura ; Natural population ; Life parameter ; Index of population control

斜纹夜蛾；自然种群；生命参数；控制指数

As PTDT does in threshold traits, PTDT is valid not only for different QTL effect level, but also for maker with multiple alleles and multiple tightly linked markers.(2) Under an appropriate selection ratio s (in this study, s is 0.2, 0.4, 0.6, 0.8, respectively), the power of PTDT can be improved and the genotying individuals can be decreased using selective genotyping design. However, the power of PTDT is related with population size and population structure, an appropriate selection ratio can be defined by simulation based on the existing data.(3) Among the three transforming methods, mixed-family selection is the best, full-sib selection has same power to mixed-family selection in many parameter combinations, and Estimated Breeding Value selection is inferior to them.

数量性状QTL定位的模拟研究结果表明：(1)数量性状经有效转化后，PTDT对数量性状QTL定位保持了阈性状QTL定位的稳健与高效，对不同效应大小的QTL(10％，30％，50％)PTDT都是一个有效的分析方法；(2)在多等位基因标记、多标记方面，PTDT的检验功效与阐性状分析时一样高效；(3)在合适的选择率下(本研究的分别为0.2，0.4，0.6，0.8，1.0)，选择性基因型测定不仅可以减少基因型测定的数量，而且可以提高PTDT的检验功效，但选择性基因型测定的PTDT检验功效很大程度上与群体大小和结构有关，这个可根据具体情况通过模拟找到一个合适的选择率；(4)三种转化方法的转化效力结果表明，家系内混合家系选择的转化效力最高，家系内全同胞选择次之，估计育种值选择的转化效力较差。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。