土壤细菌多样性空间预测方法对比

为探索适合土壤微生物多样性的空间预测方法,本文以内蒙古中部赤峰市周边为研究区域,采集35个草地土壤样品,利用高通量测序技术,结合从相关网站获取的气候、植被和高程相关数据集,采用多元线性回归(MLR)、普通克里格(OK)、回归克里格(RK)和经验贝叶斯克里格回归预测(EBKR)4种方法,对土壤细菌多样性进行空间预测,并比较其预测精度。结果表明：干旱指数、年平均降水和净光合作用是解释土壤细菌多样性变化的最佳环境变量组合;4种方法预测的细菌多样性空间分布总体趋势相似,均表现为东南高西北低,但涉及回归的3种方法可以更好地反映细菌多样性的局部变异特征;MLR、OK、RK和EBKR的留一交叉验证决定系数(R~2)分别为0.408、0.439、0.476和0.638,ME分别为-0.065、0.033、0.017和-0.009,RMSE分别为5.23、5.04、4.95和4.05,表明OK的预测精度稍高于MLR,而整合了辅助环境变量的RK和EBKR的预测精度得到进一步提升,且由于EBKR克服了RK用单一半方差函数概括所有位置数据空间结构的局限性,其预测精度最高。综上可知,结合辅助环境变量并同时考虑空...     

EXCEL在毒力回归计算中的应用

本文介绍了应用EXCEL进行毒力回归分析、计算LC50 ,a,b,相关系数 ,以及SE ,LC50 的 95 %置信区间和共毒系数的方法。     

具有空间自相关残差的回归模型及其应用

提出了具有空间自相关残差的多变量回归问题,这种残差包括单点、局部和区域化三种尺度.文中提出了两种处理空间自相关的方法:把自相关加入残差协方差作参数的改进估计──相邻相关方法和把残差作区域化最优自相关估计──一般空间自相关方法.用森林对舞毒蛾危害敏感性概率的大范围估计为例,比较了传统回归方法和本文方法间的差异,交叉检验结果表明本文的方法明显优于直接回归方法,这说明加入空间自相关对空间回归问题是必要的.     

多元模糊回归在害虫测报上的应用

介绍了多元模糊回归（AnalysisforMultipleFuzzyRegression）害虫预测方法。建立了安徽徽州地区稻纵卷叶螟五（3）代二峰日蛾量的模糊隶属函数集。对历史资料的回代验证与独立样本的试报,结果令人满意,拟合率在90％以上。分级预报的结果比多元回归方法更为明确。     

我国洪涝灾害受灾及成灾面积的预测分析

运用ＳＡＳ软件的非线性回归,并结合马尔可夫链方法建立了因洪涝灾害造成的我国农田受灾及成灾面积的２个预测模型,结果表明本文所作的预测效果较好,为我国的灾害预测提供了一种方便实用的方法。     

前瞻研究中多因素人群归因危险度的Poisson回归模型估计

本文提出多因素前瞻研究中利用Poisson回归发病率预测模型和相对危险度估计调整和综合人群归因危险度的方法,与Bruzzi等和Deubner等提出的多因素人群归因危险度估计方法进行了比较,强调在前瞻资料的人群归因危险度的估计中利用poisson回归模型考虑失访病例和随访时间效应,并能直接估计相对危险度的优势.应用所建立的方法对启东县肝病人群14年前瞻观察资料进行肝癌危险因素的人群归因危险度的估计。     

多元统计中Logistic回归模型参数估计的一种方法及应用

本文提出一多元统计中Logistics回归模型参数的估计方法──极大似然估计法,使得很容易在计算机上应用,并建立了大兴安岭地区秋季人为火发生预报模型。     

生长曲线参数估计的一种新方法-优化回归组合法

在现有文献研究的基础上,对生长曲线参数估计问题又作了进一步研究,给出了生长曲线参数估计的一种新方法优化回归组合法,该方法创造性地将最优化方法与回归方法结合在一起,利用最优化理论中的区间搜索和一维搜索,可以得到一系列c^＊值,利用回归方法可求得与其相对应的一系列a和b的值．当c取最优值c时,a和b便得到最优值a^＊和b^＊经示例计算表明,这种参数估计法具有较高的精度,     

比较逻辑斯蒂与地理加权逻辑斯蒂回归模型在福建林火发生的适用性

林火预测预报是科学有效进行林火管理的前提,是林业管理部门和科研工作者的广泛关注的领域。逻辑斯蒂回归(Logistic Regression,LR)是目前国内外广泛应用于森林火灾预测的模型方法,然而近年来有学者发现该方法没有充分考虑林火影响因子的空间相关性和异质性,从而导致模型拟合结果偏差。地理加权逻辑斯蒂回归(Geographically weighted logistic regression,GWR)模型考虑到了模型变量之间的空间相关性,有效提高的模型的拟合能力。为探讨GWLR模型在福建林火预测上的适用性,本研究应用LR和GWLR两种方法分别建立福建省森林火灾与气象因子的预测模型,通过模型拟合能力对比,判断在GWLR的适用性。研究以2000—2005年福建地区森林火灾卫星火点数据和每日气象因子为基础,将全样本分为60%的建模数据和40%的校验数据,并重复5次,建立5个样本组。选择在5个样本组中3个及以上表现显著的变量进入最终模型。研究结果表明GWLR在模型拟合度、模型残差、空间自相关性以及预测准确率等方面均优于LR模型,说明充分考虑模型变量的空间异质性有助于提高模型的预测精度,同时也验证了GWLR在福建地区林火预测上的适应性。此外,模型参数结果显示,"日最高地表气温"、"日最低地表气温"、"日平均风速"、"24小时降水量"、"日最高本站气压"、"日照时数"、"日最高气温"和"日最小相对湿度"8个因子对福建省林火发生有显著影响,研究结论为福建地区林火预测预报提供了新的方法。     

基于地理加权回归克里格的日平均气温插值

气温是大量农业、水文、气候、生态模型的输入变量.在地形复杂的区域,考虑气温与环境变量的线性回归关系和残差的自相关性的方法(如回归克里格法,regression Kriging,RK)是目前气温插值的主要方法.但此类方法多使用基于普通最小二乘的全局回归技术,没有顾及回归关系的空间非平稳性.地理加权回归克里格(geographically weighted regression-Kriging,GWRK)是一种既能顾及回归关系的空间非平稳性、又能考虑残差的自相关性的一种插值方法.本文用RK和GWRK对海南岛2013年12月18日的日平均气温进行插值并进行比较研究.依相关性分析和逐步回归分析的结果,采用RK1(以海拔为辅助变量)、GWRK1(以海拔为辅助变量)、RK2(以纬度、海拔、海陆距离为辅助变量)和GWRK2(以海拔、海陆距离为辅助变量)4种模型进行研究,并用80个验证站评估4种模型的精度.结果表明:GWRK1模型的最大正误差、最大负误差、平均绝对误差、均方根误差均最接近于0.从最大正误差、平均绝对误差、均方根误差3个指标看,考虑更多辅助变量的RK2、GWRK2模型反而不及只考虑海拔的RK1、GWRK1模型,表明RK2、GWRK2模型中辅助变量之间的相关性对插值结果有较大影响.     

Biplots in Reduced-Rank Regression

Regression problems with a number of related response variables are typically analyzed by separate multiple regressions. This paper shows how these regressions can be visualized jointly in a biplot based on reduced-rank regression. Reduced-rank regression combines multiple regression and principal components analysis and can therefore be carried out with standard statistical packages. The proposed biplot highlights the major aspects of the regressions by displaying the least-squares approximation of fitted values, regression coefficients and associated t-ratios. The utility and interpretation of the reduced-rank regression biplot is demonstrated with an example using public health data that were previously analyzed by separate multiple regressions.     

Genome-Wide Regression and Prediction with the BGLR Statistical Package

Many modern genomic data analyses require implementing regressions where the number of parameters (p, e.g., the number of marker effects) exceeds sample size (n). Implementing these large-p-with-small-n regressions poses several statistical and computational challenges, some of which can be confronted using Bayesian methods. This approach allows integrating various parametric and nonparametric shrinkage and variable selection procedures in a unified and consistent manner. The BGLR R-package implements a large collection of Bayesian regression models, including parametric variable selection and shrinkage methods and semiparametric procedures (Bayesian reproducing kernel Hilbert spaces regressions, RKHS). The software was originally developed for genomic applications; however, the methods implemented are useful for many nongenomic applications as well. The response can be continuous (censored or not) or categorical (either binary or ordinal). The algorithm is based on a Gibbs sampler with scalar updates and the implementation takes advantage of efficient compiled C and Fortran routines. In this article we describe the methods implemented in BGLR, present examples of the use of the package, and discuss practical issues emerging in real-data analysis.     

Offspring-parent regression for a binary trait

Summary Offspring-parent regression is often used to estimate the heritability of a quantitative trait. It is shown that for a purely binary trait, the regression of offspring on one parent is always linear, while that on both parents or mid-parent is generally nonlinear. However, the regressions are linear on a logistic scale.     

Platynereis nadiae sp. n. (Polychaeta: Nereididae) from Italian coasts

A new species, Platynereis nadiae sp. n. (Polychacta: Ncrcididac), from thc Mediterranean Sea is described. It is clearly distinguished from the other Platynereis species by the distribution and the morphology of the homogomph falciger setae and by the structure of thc tcntacular cirri.     

Invasiveness of alien plants in Brussels is related to their phylogenetic similarity to native species

Aim Understanding the processes that drive invasion success of alien species has received considerable attention in current ecological research. From an evolutionary point of view, many studies have shown that the phylogenetic similarity between the invader species and the members of the native community may be an important aspect of invasiveness. In this study, using a coarse‐scale systematic sampling grid of 1 km², we explore whether the occupancy frequency of two groups of alien species, archaeophytes and neophytes, in the urban angiosperm flora of Brussels is influenced by their phylogenetic relatedness to native species. Location The city of Brussels (Belgium). Methods We used ordinary least‐squares regressions and quantile regressions for analysing the relationship between the occupancy frequency of alien species in the sampled grid and their phylogenetic distance to the native species pool. Results Alien species with high occupancy frequency in the sampled grid are, on average, more phylogenetically related to native species than are less frequent aliens, although this relationship is significant only for archaeophytes. In addition, as shown by the quantile regressions, the relationship between phylogenetic relatedness to the native flora and occupancy frequency is much stronger for the most frequent aliens than for rare aliens. Main conclusions Our data suggest that it is unlikely that species with very low phylogenetic relatedness to natives will become successful invaders with very high distribution in the area studied. To the contrary, under future climate warming scenarios, present‐day urban aliens of high occupancy frequency are likely to become successful invaders even outside urban areas.     

Deletion diagnostics for alternating logistic regressions

Deletion diagnostics are introduced for the regression analysis of clustered binary outcomes estimated with alternating logistic regressions, an implementation of generalized estimating equations (GEE) that estimates regression coefficients in a marginal mean model and in a model for the intracluster association given by the log odds ratio. The diagnostics are developed within an estimating equations framework that recasts the estimating functions for association parameters based upon conditional residuals into equivalent functions based upon marginal residuals. Extensions of earlier work on GEE diagnostics follow directly, including computational formulae for one‐step deletion diagnostics that measure the influence of a cluster of observations on the estimated regression parameters and on the overall marginal mean or association model fit. The diagnostic formulae are evaluated with simulations studies and with an application concerning an assessment of factors associated with health maintenance visits in primary care medical practices. The application and the simulations demonstrate that the proposed cluster‐deletion diagnostics for alternating logistic regressions are good approximations of their exact fully iterated counterparts.     

Relationships between otolith size and fish length in some mesopelagic teleosts (Myctophidae,Paralepididae, Phosichthyidae and Stomiidae)

Length–mass relationships and linear regressions are given for otolith size (length and height) and standard length (L_S) of certain mesopelagic fishes (Myctophidae, Paralepididae, Phosichthyidae and Stomiidae) living in the central Mediterranean Sea. The length–mass relationship showed isometric growth in six species, whereas linear regressions of L_S and otolith size fit the data well for all species. These equations represent a useful tool for dietary studies on Mediterranean marine predators.     

肉鸡消化器官生长规律的研究

选艾维茵肉鸡商品雏２００只,按常规饲养管理,于初生和１～７周龄的周末,分性别各解剖８只,测量消化器官重量及消化道各部分长度,并进行与体重变化的回归分析。结果：消化器官重量及消化道各部分的长度随体重同步变化,约在４周龄时消化器官重超过饲养阶段的平均数。消化器官重量及消化道长度与体重变化的幂回归的相关系数最高。     

Effect of Soil Chemical and Physical Properties on Sorption and Desorption Behavior of Lead in Different Soils of India

Lead (Pb) is a non-biodegradable contaminant, present in the environment, especially near lead-based industrial sites, agricultural lands, and roadside soils. Bioavailability of Pb in the soil is controlled by the sorption and desorption behavior of Pb, which are further controlled by the soil chemical and physical properties. In this study, sorption and desorption amounts of Pb in soil were compared with soil physical (sand, silt, clay content) and chemical (pH; electrical conductivity, EC; percent organic carbon, (%OC); cation exchange capacity, CEC) properties. Twenty-six surface soils (0–5cm), expected to vary in physical and chemical properties, were collected from different parts of India and were treated with known concentration of Pb solution (40 μg/L). The amount of Pb sorbed and desorbed were measured and correlated with soil properties using simple linear regressions. Sorption was significantly (p ≤ 0.05) and positively correlated with pH, and %OC; desorption was significantly (p ≤ 0.05) negatively correlated with the same two factors. Stepwise multiple regressions were performed for better correlations. Predicted sorption and desorption amounts, based on multiple regression equations, showed reasonably good fit (R² = 0.79 and 0.83, respectively) with observed values. This regression model can be used for estimation of sorption and desorption amounts at contaminated sites.     

New Pferastericola species (Platyhelminthes, Rhabdocoela) and a cladistic analysis of the Pterastericolidae

Two ncw species of the family Pterastericolidae which inhabit starfish arc dcscribcd. Pterastericola bergensis sp.n. from thc oesophagus and cardiac stomach of Psilaster andromecla has posterior gonopore and lateral vitellaria. Pterastericola asamushii sp.n. from the pyloric caeca of Astropecren scopurius has unciliated epithelium postcriorly and an anterior gonopore. A cladistic analysis of thc phylogcny of the Pterastcricolidae is presented. The withdrawal of the genus Trilohorhynchus is proposed.