Precision of estimated QTL positions in granddaughter designs using combined haplotype sharing TDT and linkage analysis

The aim of this study was to develop the linear haplotype sharing transmission disequilibrium test (LHS-TDT) method and combine this method with the simple regression method to estimate the precision of QTL positions in granddaughter designs. This precision was determined by Monte Carlo simulation in granddaughter designs. A single bi-allelic QTL at the midpoint of a linkage group and 26 markers with 1 cM intervals and with two alleles each were simulated. Three linear models, (i.e. the simple regression model, the linear haplotype sharing TDT method and the combination of these two models) were compared. The mean of absolute differences (A) between the estimated and true QTL position of each method was considered for six different scenarios consisting of combinations of a number of markers and the most frequent haplotypes. The mean of A, using the simple regression method, was 4.38 centimorgan (cM). The means of A using the LHS-TDT method were less than the simple regression method in all scenarios and ranged from 1.86 to 3.82 cM depending on the scenario. The mean of A using the combined method was more than the LHS-TDT method and less than the simple regression method. The means of A using the combined method ranged from 2.32 to 4.36 cM. Therefore, for populations similar to those population simulated in this study, the LHS-TDT was better than the simple regression method and the combined method for precision of estimated QTL position in granddaughter designs.     

3种生长调节物质对生菜不定芽直接再生的影响

应用“３１１－Ｂ”回归最优设计研究ＡｇＮＯ３，ＡＢＡ，ＡＳＡ对生菜离体培养不定芽直接再生的影响。结果表明，ＡｇＮＯ３是良好的乙烯抑制剂，与ＡＢＡ配合使用可明显抑制愈伤产生，大大促进不定芽的直接再生；而ＡＳＡ未曾抑制愈伤产生，不是乙烯抑制剂。     

Modeling spatial variability in the life-cycle costs of low-volume forest roads

Cost estimation is probably the most decisive factor in the process of computer-aided, preliminary planning for low-volume road networks. However, the cost of construction is normally assumed to be route-independent for a specific project area, resulting in sub-optimal layouts. This is especially true for mountainous terrain and in areas with unstable subsoil. Here, we present a model for more accurately estimating spatial variability in road life-cycle costs, based on terrain surface properties as well as geological properties of the subsoil. This parametric model incorporates four structural components: embankment, retaining structures, pavement, and drainage and stream-crossing structures. It is linked to a geo-database that allows users to derive location-specific parameter values as input. In applying this model, we have demonstrated that variability in costs ranges widely for mountainous areas, with the most expensive construction being approximately five times greater there than on more favorable sites. This variability strongly affects the optimal layout of a road network. First, when location-specific slope gradients are considered, costs are reduced by about 17% from those calculated via currently available engineering practices; when both slope gradient and geotechnical formations are included, those costs are decreased by about 20%. Second, the length of the road network is increased by about 4% and 10% respectively, compared with current practices.     

极大值原理在确定人工林最优采伐年龄中的应用

人工林可看作一个离散系统,每个采伐分期中各龄级的林分面积定义为系统的状态变量,各龄级的采伐面积定义为控制变量。在控制变量的作用下,人工林从现状态经过N个采伐分期到达一个终端状态,可看作一个控制过程。寻求最优的控制过程的方法有多种,在国内外有关的研究中较为普遍的是多周期的线性规划(或非线性规划)和动态规划。但前者需为每个分期定义控制变量和状态变量,因而计算机计算时占用大量的存贮空间,后者在维数较高时因计算量太大难以求解。极大值原理是最优控制理论中的主要方法之     

Avoiding edge effects in agroforestry experiments; the use of neighbour-balanced designs and guard areas

A number of different types of edge effects on experimental plots are defined, and it is shown that they are frequently important in agroforestry experiments. Methods of eliminating edge effects, either at the design or the analysis stage, are described. Computer simulations, based on uniformity data, are used to investigate the efficacy of neighbour-balanced designs, with and without neighbour terms, for reducing the problem of neighbour effects between different treatments. It is concluded that, while neighbour-balanced designs may be useful in certain situations or in combination with other methods, it is preferable to eliminate edge effects by using adequate guard rows. Recommendations are therefore made concerning the correct use of guard areas in agroforestry experimentation.     

广州花园酒店空间改造与优化设计研究

在城市化进程快速发展的同时,一批城市高档酒店迅速崛起,导致城市早期建成的知名酒店因更新步伐较慢,而逐渐失去竞争力。因此建设时间较早、已明显老化的酒店迎来了更急迫的发展挑战。如何优化酒店原有的生态价值和人居环境,提升酒店的服务体验与综合发展成为重要的研究课题。以广州花园酒店为例,利用“道法自然”“以人为本”的设计思想,从优化酒店公共空间序列、完善景观层次、丰富植物种类及色彩、提升景观群落韵律等方面,提出酒店景观空间的优化、改造与再利用措施,力求提升酒店的竞争力。     

回归最优设计法在水培白菜肥料效应中的应用

利用“416-A”回归最优设计研究Ca(NO3)2?4H2O、KNO3、NH4H2PO4、MgSO4?7H2O对水培白菜的产量效应。数学模拟建立了四种肥料与白菜产量的回归方程：y=97.808-4.337x1+3.445x2-2.690x3+8.299x4-6.894x1x2+17.331x1x3-7.389x1x4-3.191x2x3+6.364x2x4+0.063x3x4-9.629x12-17.150x22-17.915x32-24.066x42。经检验回归关系显著，并对回归系数进行了检验。从回归方程可得：MgSO4?7H2O对产量以直接作用为主，其次为Ca(NO3)2?4H2O、KNO3和NH4H2PO4。Ca(NO3)2?4H2O与其它三种肥料均有交互作用，其中与NH4H2PO4交互作用达极显著水平。从产量效应回归关系优选出配方浓度为：Ca(NO3)2?4H2O：971mg/L；KNO3：931mg/L；NH4H2PO4：204mg/L；MgSO4?7H2O：581mg/L。采用回归最优设计结合水培研究肥料效应精确可行。     

发根农杆菌介导的向日葵遗传转化

本研究首次报道了发根农杆菌介导的向日葵遗传转化和毛状根形成的优化条件。由发根农杆菌诱导向日葵子叶和下胚轴形成的根在含卡那霉素（200 mg/L，kanamycin）的选择培养基(1/2 MS)上选择，12 d后存活的根转到无激素培养基上能快速生长，经分子检测证实其为毛状根。同时着重研究了不同诱导条件对向日葵毛状根形成的影响。结果发现适用于毛状根形成的最优条件为菌株R1205，菌液浓度（OD₆₀₀）1.0，15 min感染，共培养3 d，培养基pH 6.5，30 μmol/L乙酰丁香酮（acetosyingone）。在此条件下，子叶和下胚轴的毛状根形成率分别达到23.7％和81.6％。     

精准农业土壤采样密度研究——以上海精准农业试验示范基地为例

通过土壤密集采样识别农田土壤物理生化性状的空间差异,构建土壤与农作物产量关系模型,用间接方法提高土壤性状信息的分辨率并定量评价这些信息的可靠性非常必要。在评价多种插值方法的基础上,对中国科学院上海精准农业示范基地每公顷3个样本、等距离系统抽样的280个土壤有机质样本采用克立格方法进行插值,估算样本之间土壤有机质含量和分析估算的可靠性,并与距离倒数函数插值法进行对比。对几个减少样本数量的方案进行分析,提出在满足精准水稻种植管理分区要求前提下可减少1/2原有土壤采样样本,并给出适于水稻精准种植土壤采样设计的逐步优化方法。     

Coordinated pest management decisions in the presence of management externalities: The case of greenhouse whitefly in California-grown strawberries

Optimal pest management can be compounded by externalities associated with management decisions among adjacent crop fields managed by agricultural producers. In this paper, a bioeconomic model is used to measure the effects of management decisions on optimal pest management. The case of the greenhouse whitefly invasion of California-grown strawberries is considered. Results show that coordinated pest management decisions among host crop growers may improve returns, but only during certain parts of the strawberry growing season. Two generalizable pest management policy implications are presented.