Effects of wind turbines and other physical elements on field utilization by pink-footed geese (Anser brachyrhynchus): A landscape perspective

The effects of wind turbines and other physical landscape elements on field utilization by wintering pink-footed geese (Anser brachyrhynchus) were studied in a Danish farmland landscape. Within the study area geese were feeding on pastures, which together with cereals were the main crop types. Apart from wind turbines a variety of potentially disturbing landscape elements was present, e.g., high-power lines, windbreaks, roads and settlements. Patterns of field use were assessed by measuring goose dropping densities along transects perpendicular to wind farms (with turbines in clusters and in lines) and other landscape elements. Local effects were expressed in terms of `avoidance distance', i.e., the distance from a given landscape element to the point at which 50% of maximal dropping density was reached. The spatial distribution of landscape elements within an eight km radius from the goose roost was determined from aerial photographs. The area occupied by various elements, together with the adjacent zones which were not available to geese due to their associated avoidance distances, were quantified using Geographic Information System (GIS).The avoidance distance of wind farms with turbines in lines and in clusters were ca 100 m and ca 200 m, respectively. Geese did not enter the area between turbines within the cluster. At the landscape level, the combined effect of physical elements other than wind turbines caused an effective loss of 68% of the total field area (40 km²). Wind turbines caused an additional loss of 4% of the field area. However, of the remaining area available to geese (13 km²), wind turbines caused a loss of 13% of the total area. The habitat loss per turbine was higher for the wind farm with turbines arranged in a large cluster than for wind farms with turbines in small clusters or lines. This difference was mainly due to the fact that wind farms in small clusters or with a linear layout were generally placed close to roads or other elements with existing associated avoidance zones, whereas the large cluster was placed in the open farmland area. The avoidance zones associated with physical elements in the landscape do not take into account possible synergistic effects and, hence, actual field areas affected are likely to be minimum estimates. Implications of these findings for planning of wind farms in areas of conservation interest to geese are discussed.     

Relationship Between Heterosis and Parental Genetic Distance Based on Molecular Markers for Functional Genes Related to Yield Traits in Rice

The genetic distances among 18 cytoplasmic male sterile lines and 11 restorer lines were analyzed with molecular markers derived from yield-related functional genes.The correlation between parental genetic distance and heterosis was investigated by analyzing the performance of 47 combinations.The results showed that the genetic distance was significantly correlated with yield heterosis(r=0.29*),but not significantly correlated with heterosis for other traits,such as number of effective panicles per plant,se...     

温室机器人道路识别与路径导航研究——基于红外测距

针对温室内移动机器人的应用需求,提出了一种基于红外线测距的温室机器人自主导航算法,并使用模糊算法对导航误差进行控制,实现了温室机器人的精确自主移动功能。温室机器人导航过程中,当红外线接收管接受到红外线信号时,会产生一个光强电流,电流放大后可以输出一个模拟电压;根据电压值,通过编程计算,利用电压和距离的对应关系,可以得到机器人和标志物的距离误差;距离信息通过串口传输到PC机上,PC机利用模糊控制原理对距离误差进行判断,发出控制指令。实验测试发现:机器人导航的距离偏差平均值为-1.28cm,均方差为2.68,超调较小,可以实现较为精确的导航。     

群体遗传结构的理解

一个植物种群体的空间分布大致可划分为两类 :离散分布与连续分布。然而隐藏在这种表观物理分布内部的遗传变异是十分复杂的。这种变异是如何分布的呢 ?这种分布又是如何维持的呢 ?因此 ,认识一个种的群体遗传结构有助于我们理解该种的进化过程 ,并提供为遗传资源保护做出决策的重要信息。本文对三大经典遗传结构模型 (岛屿模型、步石模型及距离隔离模型 )与渐变群理论及它们的异体和发展进行了详细的分析和评述。目前获得的许多不同类型的遗传标记使这些理论的应用得到不同程度的实现 ,但由于这些理论结论涉及到许多假设 ,在实际应用时应十分慎重。作者认为许多已建立的适合于动物群体遗传结构理论不能简单地直接应用于植物群体上 ,今后一个重要的研究内容就是要建立适合于植物群体的遗传结构理论     

湟中马血清酯酶多态性的研究

采用聚丙烯酰胺凝胶电泳法对青海省湟中县９１匹马血清酯酶的多态性进行了研究。结果发现：①湟中马的血清酯酶受ＥＳ＾Ｆ，ＥＳ＾Ｉ，ＥＳ＾Ｓ和ＥＳ＾Ｏ４个等位基因的控制，其基因频率分别为０．４４５０，０．５３３０，０．０１１０和０．０１１０；②在被检湟中马的ＥＳ位点上共发现ＥＳ Ｆ，ＥＳ ＦＩ，ＥＳ Ｉ，ＥＳ ＩＳ和ＥＳ Ｏ五种表型，以ＥＳ ＦＩ为优势表型（４７．２５％）；③ＥＳ等位基因频率无性别差异；④     

花生品种抗黄1号高产栽培技术

采用播期(A)、穴粒数(B)、穴距(C)、纯氮量(D)四因素三水平的正交试验设计,研究抗黄1号的高产配套栽培技术,试验结果表明,各因素的产量效应排序为C>A>B>D,穴距和播期是影响抗黄1号产量的关键因子,其次是穴粒数,影响最小的是纯氮量。最优处理组合为A3B3C1D1,同时,还就各因素对产量结构、植株性状、生育进程等生理特性的影响作了简要分析。     

长输油气管道的焊接技术

介绍了国内外输油气管道的三种主要焊接方法,重点分析了国内近几年新建管道不同焊接方法的使用情况,同时对不同焊接方法的选用和管材与焊接材料的选用匹配进行了探讨和研究.     

解放CA10B型汽车功能模型的探讨

本文通过对黑龙江省双丰林业局提供的6台解放CA10B型汽车的使用数据的处理和分析.得出该汽车的单车年周转量及耗油率这两个主要生产参数的影响因素及功能方程.并进一步探讨了该模型对运输企业及木材生产单位的规划、管理、指挥等方面的重要意义.     

白色力克斯兔、哈尔滨白兔及杂交后代血液蛋白多态性研究Ⅱ.用血液蛋白多态性剖析亲本品种与杂种后代的遗传关系

根据所测定的白色力克斯兔(WR)、哈尔滨白兔(HW)及杂种一代(F_1,?WR×?HW)和回交一代[B_1,?WRX×?F_1,包括分离出的力克斯毛型(B_1R)和正常毛型(B_1N)]的5个血液蛋白多态系统——红细胞酯酶(Es—1、Es—2和Es—3)、前转铁蛋白(Prt)和后白蛋白(Po)的基因频率和基因型新率,比较了群体间的基因分布,估算了各群体内的平均杂合度和群体间的遗传距离,并运用类平均聚类法进行了聚类分析.结果表明,白色力克斯兔和哈尔滨白兔基因分布差异最大.亲缘关系最远;杂种一代和回交一代基因分布差异最小,亲缘关系最近;杂交一代和回交一代与白色力克斯兔亲缘关系较近,与哈尔滨白兔较远;回交一代中B_1N和B_1R间基因分布也存在一定差异.各群体平均杂合度大小为0.5223(HW)、0.4182[B_1,0.4846(B_1N)和0.3223(B_R)]、0.1105(F_1)和0.3946(WR).研究结果表明,利用蛋白多态性探讨家兔品种或品系间亲缘关系以及区分家兔品种或品系是可行的.此外,本文还结合各群体的变异性,对白色力克斯免和哈尔滨白兔的选育进行了探讨.     

Evaluating the utility of Arabidopsis thaliana as a model for understanding heterosis in hybrid crops

Despite the phenomenon of heterosis having been used to improve crop productivity for almost a century, there is little understanding of the molecular mechanisms involved. Heterosis has been described recently in the widely used plant model Arabidopsis thaliana. To assess the opportunity afforded by this system, we have developed, through pollination to a male sterile female parent (Ler ms1), a range of hybrids of A. thaliana accessions. We tested this method of hybrid production in A. thaliana by comparing seed produced by natural pollination and hand pollination of emasculated plants. Our results demonstrate that using male sterile lines, which more closely represent methods used for hybrid crop production, circumvents the problems associated with the analysis of hybrids produced from emasculated plants. We identified hybrid combinations exhibiting mid-parent heterosis for vegetative fresh weight ranging from −9 to 103% and characterised heterosis in the reciprocal hybrids of one strongly heterotic combination. We found no evidence of a relationship between the extent of genetic relatedness of A. thaliana accessions and the strength of heterosis exhibited by their hybrids. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.