Repeatability,Sensitivity, and Uncertainty Analyses of the BANCS Model Developed to Predict Annual Streambank Erosion Rates

Accelerated streambank erosion caused by channel instability can be the leading cause of sediment impairment of streams. Obtaining accurate streambank erosion rates for sediment budgeting and prioritizing mitigation efforts can be difficult and costly. One approach to quantifying streambank erosion rates is through the development and implementation of an empirically derived “Bank Assessment for Non‐point Source Consequences of Sediment” (BANCS) model. This study aims to improve the BANCS model application by evaluating repeatability between users and identifying sensitive and/or uncertain model inputs. Statistical analysis of streambank evaluations conducted by 10 different individuals suggests the implementation of the BANCS model may not be repeatable. This finding may be due to sensitive model inputs, such as streambank height and near‐bank stress level prediction method selection, and/or uncertain model inputs, such as bank material identification and the associated adjustment of erosion potential. Furthermore, it was found assessing streambanks as a group by obtaining a measure of central tendency from individual evaluations, as well as obtaining a higher level of training, may improve model implementation precision. Application of these suggestions may result in improved prediction of streambank erosion rates utilizing the BANCS model methodology.     

抗禾谷孢囊线虫基因中核苷酸结合位点区(NBS)-亮氨酸重复序列区(LRR)的克隆与序列分析

根据源于节节麦抗禾谷孢囊线虫基因Cre3及已经克隆的NBS-LRR类植物抗病基因的NBS与LRR区保守序列分别设计特异引物,从易变山羊草基因组中PCR扩增得到两个扩增条带,它们的大小分别约为530bp和1200bp.经克隆测序发现,这两个序列分别长为532bp和1175bp,且是连续的.它们有32bp的共同序列,总长为1675bp,包含了一个NBS-LRR区和一个不完整的开放阅读框,没有起始密码子、终止密码子和内含子结构.它编码一个557个氨基酸的蛋白质,分子量(Mr)为63.537×103,含有NBS区保守模体ILDD,ESKILVTTRSK,KGSPLAARTVGG,RRC-FAYCS,EGF,以及LRR区的保守模体aXXLXXLXXL.它与Cre3的核苷酸和氨基酸同源性分别为87.8%和77%,可能是一个抗禾谷孢囊线虫基因.图6参13     

NBS氧化流动注射化学发光法在土壤腐殖酸含量测定中的应用

在碱性条件下,NBS直接氧化腐殖酸产生强烈的化学发光信号,结合流动注射技术,建立了测定土壤腐殖酸含量的流动注射化学发光分析法并详细研究了影响化学发光信号强度的各种因素。方法的测定线性范围为1.0×10-7-1.0×10-3g/ml,检出限(3σ)为3×10-8g/ml。对5.0×10-5g/ml的腐殖酸进行11次平行测定,相对标准偏差为1.8%。将该法用于实际土壤样品分析,结果令人满意。