黄土沟壑区开采沉陷对地形因子的影响研究

以黄土沟壑区的采煤沉陷区为研究对象,以地面数字高程模型和开采沉陷预计结果为基础数据,基于ArcGIS平台对煤矿开采沉陷区的地形数据进行分析处理,研究开采沉陷前、后地形因子的变化特征,并对不同地形因子之间的相关性进行了分析.研究结果表明:黄土沟壑区地面高程、坡度、坡向、起伏度等各种地形因子均受开采沉陷影响而发生改变,开采沉陷和地形因子之间存在明确的量化关系,而平均高程、起伏度、曲率、沟壑密度等因子与地面坡度之间存在显著的相关性.研究结果有助于揭示煤矿开采沉陷区的地形地貌演变规律,为保护西部矿区的生态环境提供技术支持.     

宅基地置换中农民参与权问题研究

对宅基地置换中农民参与权的概念进行界定,阐述宅基地置换中农民参与权的法理基础和包含的内容.根据常熟市经济开发区的宅基地置换实践,参照宅基地置换中农民参与权定义总结农民参与权受限的具体表现.针对宅基地置换中农民参与面临的困境,提出保护农民宅基地置换参与权的政策建议.     

亚布力林业局耕地专项核查情况分析

黑龙江省森工林区亚布力林业局耕地专项稽查工作以卫片判读为依据,坚持实事求是的原则,积极与地方政府取得联系、沟通,为准确认定权属界线提供了保障,也为确认测量被侵占耕种的林地数量打下了基础。     

谷子杂交种与常规种光合和叶绿素荧光特性的比较

为了明确杂交谷的光合优势是否是其产量高于常规谷的一大主因,本研究于2013年对常规谷晋谷21号和杂交谷张杂谷5号的光合和叶绿素荧光特性进行比较。采用完全随机设计,每个品种种植5个小区,在拔节期和灌浆期分别测定各项光合指标。结果表明,在拔节期,张杂谷5号的净光合速率、PSⅡ实际光化学量子产量显著高于晋谷21号;但在灌浆期,张杂谷5号和晋谷21号之间的总叶绿素含量、净光合速率、蒸腾速率、气孔导度、胞间CO2浓度、PSⅡ实际光化学量子产量、光化学淬灭参数和非光化学淬灭参数都存在显著差异。总体杂交谷在拔节期和灌浆期的光合性能高于常规谷。     

黄河河道变迁对黄淮流域城市的影响——以安徽省砀山县为例

历史上黄河以“善淤、善决、善迁”称著于世,北宋之前,以北流为主,南宋时起,改道南泛,清咸丰五年之后,复北流。南泛期间,在黄淮大平原上来回滚动,对砀山河段变迁的考证,印证了河道多次变迁。黄河河道在黄淮地区的变迁对当地造成了严重的影响,主要表现为水灾频繁、摧屋毁稼,沙灾伴之、破坏环境,淹没城市、城址变迁,治理黄河、建设河防。     

基于随机森林算法和气象因子的砀山酥梨始花期预报

准确预报始花期是制定砀山酥梨花期管理措施和赏花活动方案的重要基础。该文利用1983-2018年砀山酥梨始花期的定位观测物候数据和平行观测的气象资料，采用线性趋势法，揭示始花期演变趋势；采用相关分析，筛选影响始花期的关键气象因子，依据不同预报日期构成特征变量集；采用随机森林算法（Random Forest, RF），自3月11日开始预报到3月25日终止预报，每日训练1个预报模型。结果表明，1）1983－2018年始花期呈极显著提早发生趋势，每10a约提前2.750 d（P＜0.001）。2）16个逐日气象预报模型中，共计有200个气象因子与始花期早迟密切相关，相关系数在0.469～0.789之间；各气象预报模型的训练集与测试集的平均正确率（Nd）分别为92.9%和75.5%、平均均方根误差（RMSE）分别为1.693～2.870和2.240～7.237、平均决定系数（R2）分别为0.891和0.701。3）2019年试验预报中，提前15日准确预报出当年始花期。该文研究表明RF在梨树始花期逐日气象预报中有一定业务应用潜力，预报准确率基本满足气象服务需求。     

Mapping and validation of the quantitative trait loci for leaf stay‐green‐associated parameters in maize

Functional stay‐green is generally regarded as a desirable trait of varieties in major crops including maize. In this study, we used an F_3:4 recombinant inbred line population with 165 lines from a cross between a stay‐green inbred line (Zheng58) and a model inbred line (B73) using 211 polymorphic simple sequence repeat markers to map quantitative trait loci for three stay‐green‐associated parameters, chlorophyll content, photosystem II photochemical efficiency and stay‐green area, at maturity stage, detected a total of 23 quantitative trait loci (QTL) on nine chromosomes. Single QTL explained 3.7–13.5% of the phenotypic variance. Additionally, we validated some important stay‐green QTL using a heterogeneous inbred family approach and found that the stay‐green‐associated parameters were significantly correlated with the plant yield. This study may contribute to a better insight into the regulatory mechanism behind leaf stay‐green in maize and a novel development of elite maize varieties with delayed leaf senescence through molecular marker‐assisted selection.     

油松林木菌根化造林试验效果分析

通过采用3年生油松苗,接种牛肝菌和血红铆丁菇外生菌根菌进行育苗和造林试验,结果表明:油松3a幼苗外生菌根的浸染率达到61%,油松造林外生菌根菌浸染率达到57%。山地造林外生菌根菌的浸染率明显小于圃地育苗接种苗浸染率。造林成活率比对照提高8.9%,苗高生长量提高11.5%,地径生长量提高17.3%。     

我国煤炭和电力行业财务绩效相关性的实证研究

以煤电行业上市公司为样本,选取1997-2013年的面板数据,应用描述统计、因子分析法和回归分析法对我国煤炭行业和电力行业财务绩效的相关性进行研究.结果显示:1)1997-2002年,煤炭和电力行业财务绩效总体上均呈现较平稳的上升趋势;2002年以后煤炭和电力行业财务绩效变化趋势差异明显,前者在2002-2011年间总体向上但随后快速恶化,后者在2002-2008年间逐年恶化,2009年起呈现稳步回升势头.2)1997-2002年间,煤炭和电力行业财务绩效关系不显著;2003-2013年间煤炭和电力行业财务绩效间存在显著负相关性.分析认为,原因在于煤电价格的双轨制使利润在我国煤炭行业和电行业间不合理的分配,这种影响进一步体现在其行业的财务绩效上.     

Selection of soybean elite cultivars based on phenotypic and genomic characters related to lodging tolerance

Soybean lodging can result in serious yield reduction. Detecting the quantitative trait loci (QTL) associated with lodging tolerance for their further application in marker‐assisted selection (MAS) has the potential to enhance soybean breeding efficiency. In this study, a genome‐wide association analysis (GWAS) was performed to identify soybean accessions that could potentially be used to produce lodging‐tolerant varieties, based on the comprehensive evaluation of lodging scores (LS) obtained for the parental cultivar “Tokachi nagaha” and its 137 derived cultivars. Results showed that genotype, environment and genotype × environment interaction significantly influenced LS. Of the 31 significant SNPs identified, 22 were consistently detected in two or more environments and 27 SNPs were located in or close to agronomically important QTL mapped by linkage analysis. Best linear unbiased predictors (BLUPs) of LS tend to decrease with the elite alleles contained by accessions increasing. Some excellent accessions, with lower BLUPs and D_i (stability coefficients) values and more elite alleles, were selected. This study contributed to understand the genetic mechanism of lodging, providing genetic and phenotypic information for MAS.