多元回归在DEA方法指标降维中的应用

在数据包络分析方法中,由于投入产出指标数量和决策单元个数比较接近,使得最终产生多个DEA有效单元和弱DEA有效单元,不利于比较一些决策单元的有效性的差别.本文通过多元线性回归方法对投入指标进行筛选降维,能够使得决策单元间的DEA有效性进一步细化.并以我国1990年到2006年中国能源经济发展数据为例,对利用多元回归对数据包络分析指标降维前后的DEA有效性进行了比较.     

三江源兴海地区西北针茅产量影响因子的主成分分析

利用主成分分析法和多元逐步回归法分析影响三江源兴海地区西北针茅（Stipa sareptana Beckervat．krylovii）牧草产量的因子。结果表明,影响西北针茅牧草产量的主成分因子以水分因子为主,温度和光照因子其次;以各因子为自变量,西北针茅牧草产量为因变量,进行多元逐步回归分析,建立产量回归方程,方程的相关系数达0．9873,各因子影响牧草产量的大小为4月降水量＞4～8月降水量＞7月降水量＞8月日照时数＞6月日照时数。     

我校教学比赛结果评价的Hotelling T2检验与分析

运用多元HotellingT2检验方法,对我校首届青年教师教学比赛的专家评价结果进行对比分析。结果表明,高级职称与中初级职称教师、男教师与女教师的课堂教学和教学文件资料得分无显著差异;不同"学科组"教师的课堂教学得分与教学文件资料得分有显著差异。检验证明了我校首届青年教师教学比赛的评价指标是科学的,专家评价的比赛结果也是客观、合理的。     

Small-scale effects of historical land use and topography on post-cultural tree species composition in an Alpine valley in southern Switzerland

Investigations of spatial patterns in forest tree species composition are essential in the understanding of landscape dynamics, especially in areas of land-use change. The specific environmental factors controlling the present patterns, however, vary with the scale of observation. In this study we estimated abundance of adult trees and tree regeneration in a Southern Alpine valley in Ticino, Switzerland. We hypothesized that, at the present scale, spatial pattern of post-cultural tree species does not primarily depend on topographic features but responds instead to small-scale variation in historical land use. We used multivariate regression trees to relate species abundances to environmental variables. Species matrices were comprised of single tree species abundance as well as species groups. Groups were formed according to common ecological species requirements with respect to shade tolerance, soil moisture and soil nutrients. Though species variance could only be partially explained, a clear ranking in the relative importance of environmental variables emerged. Tree basal area of formerly cultivated Castanea sativa (Mill.) was the most important factor accounting for up to 50% of species’ variation. Influence of topographic attributes was minor, restricted to profile curvature, and partly contradictory in response. Our results suggest the importance of biotic factors and soil properties for small-scale variation in tree species composition and need for further investigations in the study area on the ecological requirements of tree species in the early growing stage.     

准噶尔盆地沙漠植被多元特征分析

用主成分分析排序法分析准噶尔盆地沙漠植被的多元特征。结果表明:根据植物种的盖度和出现频率认为,梭梭(Haloxylona mmodendron)、琵琶柴(Reaumuria soongorica)、西伯利亚白刺(Nitraria sibirica)、角果藜(Ceratocarpus arenarius)和对节刺(Horaninowia ulicina)是该地区最为重要的沙漠植被组成成份及地带性植物;一年生植物表现出较为重要的特征,是沙漠植被中重要的组成成份;与前人的研究成果一致,可为准噶尔沙漠植被的演替提供有价值的资料。     

Sexual dimorphism in limb long bones of the German Shepherd Dog

The study of sexual dimorphism in dog anatomy, especially with regard to skeletal elements, has received little attention. The present work focuses on elements of the canine stylo- and zeugopodium, less documented than the skull or pelvis in the literature. In order to identify only sex-dependent effects, we analysed a single breed: the German Shepherd Dog. Data come from 25 dogs, with a balanced sex ratio (12 males and 13 females). Four skeletal elements of the forelimb and hindlimb (humerus, radius, femur, tibia) were each measured using seven linear morphometric variables. Univariate and multivariate analyses were then performed on these 28 variables. For all measurements, males are on average larger than females, with a mean sexual dimorphism ratio of 1.07. Sexual dimorphism is significant for 92.8% of the variables. Except of femoral measurements, diaphyseal values show the highest grade of sexual dimorphism. The mean level of disparity is higher in the forelimb (1.08) than in the hindlimb (1.05). A significant dimorphism is shown for the first component of principal component analyses conducted on each skeletal element, and for the second component with humerus measurements. Discriminant functions for sex identification give success rates included between 82% for the radius and 93% for the femur, the latter providing the highest reported score for sex identification in dogs from any skeletal element. These complementary statistic methods highlight a more dimorphic forelimb in size and a more dimorphic hindlimb in shape.     

Short-term impact of two liquid organic fertilizers on Solanum lycopersicum L. rhizosphere Eubacteria and Archaea diversity

This study evaluates the effect of two different kinds of liquid organic fertilizers and a mineral fertilizer on microbial populations (Eubacteria and Archaea) living in the tomato rhizosphere. The organic fertilizers comprised a stillage from bakery yeasts production, characterized by acidic pH and high organic nitrogen content, as well as a vermicompost extract with alkaline pH and low nitrogen content. The number of operational taxonomic units (OTUs) of Archaea species significantly increased after the addition of both the organic and mineral fertilizers, in comparison to the unfertilized control. Eubacteria OTUs increased only in plants treated with the stillage. T-RFLPs profiles identified different clusters of soil rhizospheric Archaea and Eubacteria in treatments of both organic and mineral fertilizers. However, multivariate analyses performed on indicators of genetic diversity, based on the T-RFLPs profiles, and Shannon and equitability indexes of the Archaea and Eubacteria communities, pointed out marked differences between the control (or the mineral fertilization) and the organic fertilizers. The latter treatments induced also a higher root growth and a modification of the root architecture in comparison to both control and mineral fertilizer. The results are discussed with reference to the effect of the organic products on rhizospheric soil characteristics and the relationships between the plant and the rhizospheric microorganisms.     

Phenology and grape ripening characteristics of cv Tempranillo within the Ribera del Duero designation of origin (Spain): Influence of soil and plot characteristics

The aim of this research was to evaluate the variability of phenology and ripening characteristics of the Tempranillo variety within the Ribera del Duero Designation of Origin (Spain). This area covers approximately 115 km along the Duero River, where Tempranillo is the main variety cultivated. The analysis included the information recorded during the period 2004–2013 in 20 plots for phenology dates and 26 plots for grape characteristics. The variability in soil, phenology, grape quality and plot characteristics throughout the Ribera del Duero DO as well as their relationships were evaluated using multivariate analysis. Four different groups of plots were characterized as distinct from each other, with differences in elevation, distance to the Duero River and soil type. The differences in phenology among groups started during flowering and were observed through the end of the growth cycle. Despite the high phenological variability driven by year to year variations in climate characteristics, it was possible to define the soil and plot characteristics that favor advanced phenology within the Ribera del Duero DO. Regarding grape ripening characteristics, the highest acidity and anthocyanin concentrations were found in plots with soils with higher clay and organic matter content. The effect was greater in the wet and intermediate years, than in dry years. High variability in phenology and ripening characteristics is found within the Ribera del Duero related to site soil and landscape characteristics, and from year to year due to climatic conditions. Zones with common characteristics and similar response have been identified within the area. The results highlight the potential of establishing viticultural zones with differences in vineyard treatment and management and the elaboration of site specific wine styles from those zones.     

多变量时间剩余协克立格模型理论及其在水文数据分析中的应用

本文将随机水文学和多变量地质统计学相结合，提出了多变量时间剩余协克立格模型。该模型将水文变量的周期性成分和趋势性成分视为确定性分量从原始各测站水文时间序列中剔除，剔除剩下的剩余值属于时空随机函数，从而以这种剩余值作为研究变量去刻划原水文变量的时空相关特征。该模型可用于水文变量的插补延展和短期预报，具有较高的精度。     

Assessing the effects of marine protected area (MPA) on a reef fish assemblage in a northwestern Mediterranean marine reserve: Identifying community-based indicators

Marine protected areas (MPAs) are increasingly envisaged as a tool to manage coastal ecosystems and fisheries. Assessment of their performance with respect to management objectives is therefore important. A number of MPAs provided conservation benefits for fished species. Observed benefits do not apply to all species at all times, and responses to protection are also highly variable among fish taxa. Among the many empirical studies on marine reserves, only a few designs considered ‘before and after data’ and spatial variation. In this paper, we are interested in assessing the effect of a no-take reserve on the reef fish assemblage in a northwestern Mediterranean example. Data were obtained from a three-year survey using underwater visual censuses (UVC), before and after MPA establishment. Permutational multivariate analysis of variance (PERMANOVA) and multivariate regression trees (MRT) were used to evaluate the effects of reserve protection on the reef fish assemblage, while accounting for habitat. Modelled biological responses were abundances and diversity indices calculated at different levels of the assemblage. Significant effects were found for many of these metrics. In addition to PERMANOVA, univariate models provided more insight into the magnitude and direction of effects. The most sensitive metrics were related to large species and species targeted by fishing. These results may be used to choose the metrics that are more suitable as community-based indicators of MPA impact in the perspective of monitoring programs.