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21.
This study was carried out to investigate the possibility of calibrating a prediction model for the moisture content and density distribution of Scots pine (Pinus sylvestris) using microwave sensors. The material was initially of green moisture content and was thereafter dried in several steps to zero moisture content. At each step, all the pieces were weighed, scanned with a microwave sensor (Satimo 9,4GHz), and computed tomography (CT)-scanned with a medical CT scanner (Siemens Somatom AR.T.). The output variables from the microwave sensor were used as predictors, and CT images that correlated with known moisture content were used as response variables. Multivariate models to predict average moisture content and density were calibrated using the partial least squares (PLS) regression. The models for average moisture content and density were applied at the pixel level, and the distribution was visualized. The results show that it is possible to predict both moisture content distribution and density distribution with high accuracy using microwave sensors. 相似文献
22.
Ragnar Jonsson 《Journal of Wood Science》2005,51(2):154-160
In order to understand the competitive situation of wood, it is essential to consider the end consumer of building materials. The knowledge of factors affecting the end consumers choice of building material for specific purposes, i.e., the mechanisms of substitute competition, is limited. Field studies of the British and Dutch floorcovering markets revealed that context, usage context as well as the general life situation, is of crucial importance in substitute competition. This contextual character severely limits the usefulness and adequacy of interviews with fixed-reply alternatives, as well as classical statistical methods of analysis. In this article, a qualitative approach to data gathering is combined with multivariate analysis. The results indicate that by using this methodology it is possible to determine which are the decisive predictors of material preferences, make cross-cultural comparisons, and apprehend the underlying motives or perspectives. The results further show that, unlike the other floorcovering materials studied, the determinant reasons for choosing wood appear to be exclusively nonfunctional in nature. 相似文献
23.
Gastao Viegas de Pinho Ju nior Andre R Terra Nascimento Barbara Tahara Valverde Lucas H Clemente 《林业研究》2015,(3)
In this paper we analyze and compare natural regeneration in shrub-tree community in three areas below Pinus caribaea stands and a natural area (cerrado sensu stricto). We also analyze the influence of... 相似文献
24.
不同鳊鲂属鱼类群体的形态差异分析 总被引:5,自引:2,他引:3
运用3种多元统计方法对我国鳊属长春鳊(Parabramis.pekinensis)、鲂属团头鲂(Megalobrama.amblycephala)、东江三角鲂(Megalobrama.terminalis)、钱塘江三角鲂(Megalobrama.terminalis)、厚颌鲂(Megalobrama.pellegrini)和广东鲂(Megalobrama.hoffmanni)6个群体的可数性状、可量性状和框架性状的形态学差异进行了分析。结果显示,鳊鲂属鱼类6群体在侧线鳞数、侧线上鳞数、侧线下鳞数、背鳍条数、胸鳍条数、腹鳍条数、臀鳍条数等7项形态可数性状上的差异不显著(P0.05)。对9项可量比例参数和20项框架比例参数的聚类分析结果表明,团头鲂与同属的厚颌鲂、三角鲂亲缘关系较近,这3个鲂属种群与鳊属长春鳊形态差异较大,与同为鲂属的广东鲂形态差别最大;另外,聚类分析表明三角鲂的2个地理群体(东江三角鲂、钱塘江三角鲂)也存在一定的形态差异。判别分析构建了鳊鲂属鱼类6群体的判别函数,其综合判别率为93.7%。主成分分析提取的前2个主成分的累积贡献率为77.9%,其中主成分1的贡献率为70.9%,对鳊鲂属鱼类群体间形态学差异起决定性作用的特征集中在背腹轴方向。 相似文献
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26.
Multivariate Extension of Griffing's Diallel Analysis 总被引:1,自引:0,他引:1
Diallel-cross designs have been used extensively in plant and animal breeding programs. In most cases, multiple traits are measured in the study, but the analyses are performed on each trait separately. The objective of this paper is to provide an alternative multivariate procedure so that the combining abilities among traits can be evaluated simultaneously and the interaction of combining ability and traits can be tested statistically.
Numerical example is provided from data of a rice study. Three characters, panicles per plant, percent sterility, and 100 kernel weight were used in the analysis. Results showed that some parental lines with greater combining abilities in one trait may not be so good in another trait. Also certain crosses may be better for one trait but not necessarily as good for other traits. 相似文献
Numerical example is provided from data of a rice study. Three characters, panicles per plant, percent sterility, and 100 kernel weight were used in the analysis. Results showed that some parental lines with greater combining abilities in one trait may not be so good in another trait. Also certain crosses may be better for one trait but not necessarily as good for other traits. 相似文献
27.
28.
F.M.A. Islam K.E. Basford R.J. Redden A.V. Gonzalez P.M. Kroonenberg S. Beebe 《Genetic Resources and Crop Evolution》2002,49(3):271-283
It is generally accepted that two major gene pools exist in cultivatedcommon bean (Phaseolus vulgaris L.), a MiddleAmerican and an Andean one. Some evidence, based on unique phaseolin morphotypesand AFLP analysis, suggests that at least one more gene pool exists incultivated common bean. To investigate this hypothesis, 1072 accessions from acommon bean core collection from the primary centres of origin, held at CIAT,were investigated. Various agronomic and morphological attributes (14categorical and 11 quantitative) were measured. Multivariate analyses,consisting of homogeneity analysis and clustering for categorical data,clustering and ordination techniques for quantitative data and nonlinearprincipal component analysis for mixed data, were undertaken. The results ofmost analyses supported the existence of the two major gene pools. However, theanalysis of categorical data of protein types showed an additional minor genepool. The minor gene pool is designated North Andean and includes phaseolintypes CH, S and T; lectin types 312, Pr, B and K; and mostly A5, A6 and A4 types-amylase inhibitor. Analysis of the combined categorical data ofprotein types and some plant categorical data also suggested that some othergermplasm with C type phaseolin are distinguished from the major gene pools. 相似文献
29.
We present here an indicator of soil quality that evaluates soil ecosystem services through a set of 5 subindicators, and further combines them into a single general Indicator of Soil Quality (GISQ). We used information derived from 54 properties commonly used to describe the multifaceted aspects of soil quality. The design and calculation of the indicators were based on sequences of multivariate analyses. Subindicators evaluated the physical quality, chemical fertility, organic matter stocks, aggregation and morphology of the upper 5 cm of soil and the biodiversity of soil macrofauna. A GISQ combined the different subindicators providing a global assessment of soil quality.Research was conducted in two hillside regions of Colombia and Nicaragua, with similar types of land use and socio-economic context. However, soil and climatic conditions differed significantly. In Nicaragua, soil quality was assessed at 61 points regularly distributed 200 m apart on a regular grid across the landscape. In Colombia, 8 plots representing different types of land use were arbitrarily chosen in the landscape and intensively sampled. Indicators that were designed in the Nicaragua site were further applied to the Colombian site to test for their applicability.In Nicaragua, coffee plantations, fallows, pastures and forest had the highest values of GISQ (1.00; 0.80; 0.78 and 0.77, respectively) while maize crops and eroded soils (0.19 and 0.10) had the lowest values. Examination of subindicator values allowed the separate evaluation of different aspects of soil quality: subindicators of organic matter, aggregation and morphology and biodiversity of macrofauna had the maximum values in coffee plantations (0.89; 0.72 and 0.56, respectively on average) while eroded soils had the lowest values for these indicators (0.10; 0.31 and 0.33, respectively).Indicator formulae derived from information gained at the Nicaraguan sites were not applicable to the Colombian situation and site-specific constants were calculated.This indicator allows the evaluation of soil quality and facilitates the identification of problem areas through the individual values of each subindicator. It allows monitoring of change through time and can guide the implementation of soil restoration technologies. Although GISQ formulae computed on a set of data were only valid at a regional scale, the methodology used to create these indices can be applied everywhere. 相似文献
30.