青海省农村一线教师远程教育培训效果调查与对策

通过对接受远程教育培训的青海省农村中小学一线教师的培训、再培训及问卷调查,对调查结果进行了客观地分析与总结,目的在于了解受培训教师接受教学内容的程度与教学质量,抓住学习者的特征,发现教学中存在的问题和不足,并改善教学,进一步做好青海省农村中小学现代远程教育培训工作,为今后的培训工作开辟新的方式方法,提高教学质量,以达到青海省农村中小学现代远程教育培训目标。     

农业劳动力老龄化对粮食绿色全要素生产率变动的影响研究

本文利用1991—2016年27个省(区)的粮食生产投入产出数据,在运用单元调查评估法测算各省份粮食生产污染排放量的基础上,采用Global-Malmquist-Luenberger(GML)指数与方向性距离函数测度了各省粮食绿色全要素生产率指数,并运用面板数据模型实证分析了农业劳动力老龄化对粮食绿色全要素生产率变动的影响。结果表明:1)全国大部分省份的粮食绿色全要素生产率在样本期内呈现出逐步增长的趋势,但仍处于一种低效率状态;此外,不同省份之间的粮食绿色全要素生产率变动状况差异也较大,粮食主产区的粮食绿色全要素生产率表现状况整体优于主销区和产销平衡区。2)农业劳动力老龄化与我国粮食绿色全要素生产率变动之间呈现出显著的"U型"关系,即伴随着农业劳动力老龄化程度的加深,粮食绿色全要素生产率存在先降后增的趋势,并且这种关系在粮食主产区、粮食主销区和产销平衡区均较为稳定。3)工资性收入比重以及受灾率的增高对粮食绿色全要素生产率变动均具有负向影响,而财政支农力度的提高则能够显著促进粮食绿色全要素生产率的增长。     

卧龙自然保护区拐棍竹(Fargesia robusta)无性系种群的空间分布格局

通过计算种群空间分布格局的经典指数对拐棍竹(Fargesia robusta)无性系种群在不同取样尺度上的空间分布格局和聚集强度进行了研究。利用地理信息系统计算了不同龄级分株与其他龄级分株的平均距离,探讨了分株年龄与空间分布的关系。结果表明:①拐棍竹无性系种群呈聚集分布;②种群的聚集分布的强度随着取样尺度的增大而减弱;③分株间的平均距离随龄级差距的增大而增大。     

基于SWOT分析的远程教育培育新型职业农民的发展战略思考

通过SWOT分析远程教育培育新型职业农民发展环境的优势、劣势、机会与威胁,形成SO、ST、WO、WT策略,给出SWOT矩阵图,确定采取的具体战略与策略,有助于实现远程教育培育新型职业农民的可持续发展.     

Effects of local environmental variables and geographical location on the genetic diversity and composition of Rhizobium leguminosarum nodulating Vicia cracca populations

Different legume populations are known to accommodate different genotypes of Rhizobium leguminosarum. However, in contrast to interspecific diversity and composition, very little is known regarding which environmental factors drive the genetic diversity and genetic composition of a single Rhizobium species. Based on chromosomal and plasmid genes, we quantified the genetic diversity and compositional differences of R. leguminosarum biovar viciae genotypes associated with twenty-four different Vicia cracca populations across a wide environmental and geographical range. Long-term soil nitrogen availability had a positive effect on chromosomal and plasmid diversity, whereas salinity had a negative effect on chromosomal diversity. Soil pH and geographic distance were the main factors driving compositional differences among populations. In contrast to differences in chromosomal composition, differences in the symbiotic plasmid composition were primarily related to geographic distance or unmeasured related environmental factors (e.g. host plant genetic differentiation). We propose different hypotheses to explain how long-term soil nitrogen availability affects rhizobial genetic diversity. Furthermore, our findings demonstrate that ecological processes that are known to operate at the interspecific level do not necessarily result in the same patterns at the intraspecific level.     

我国民营企业贷款的距离影响因素分析

选取我国2011年沪深两市A股的628家民营上市企业的贷款数据为样本进行实证分析发现：银行贷款量与银行到企业之间距离具有显著的负相关关系，说明银企距离是制约我国民营企业贷款的一个重要影响因素；地区金融发展与企业的银行贷款量之间具有显著的负相关的关系，说明了竞争关系对企业外地银行贷款的抑制作用不是表现在区域的银行网点的竞争，而是地区的金融发展。因此，应重视银企距离，加大地区金融发展。     

Track way distance and cover as risk factors for lameness in Danish dairy cows

This study investigates the effect of length and cover of track ways between barn and pasture on lameness in Danish dairy cows. We hypothesised that short track distances would be associated with a lower lameness probability of dairy cows compared to longer distances and that track ways with prepared cover (asphalt, gravel, slag, concrete, rubber) compared to no prepared cover (sand, soil and/or grass) would be associated with a lower lameness probability of dairy cows in grazing herds.     

Modeling internode length and branch characteristics for Pinus radiata in New Zealand

It is recognized that estimation of internode length and maximum branch size is important for the prediction of clearwood in unpruned timber stands, as well as for evaluating the quality and value of logs in general. A review of existing branch models reveals a diversity of approaches as well as a tendency for results to be species specific. Here, a branch model is developed for Pinus radiata in New Zealand, capable of predicting successive internode lengths, the number of branches on each branch cluster, and the size of each branch up to the green crown (GC) at site index age 20. Inputs to the model include tree height and diameter at breast height (dbh) (both at age 20) and basal area per hectare of the top 100 stems. Further optional inputs are an ocular count of the number of branch clusters up to the green crown, and branch factor (BF)—the size of the biggest branch in the first cluster encountered above 6 m. The vertical distributions of internode length and maximum branch diameter are found to reach maxima around 0.3–0.4 of relative height. Internode length and the number of branches per whorl were found to be independent of tree size, site index and stand density. Stems per hectare is not required as an explicit predictor variable but it appears implicitly through tree dbh. Some model output is given and the results are discussed.     

棉花杂交亲本距离估测与聚类分析方法的探讨

本研究利用四十个陆地棉亲本,经两年异地试验证明,以表型相关(r_p)矩阵代替遗传相关矩阵(r_g)作为距离分析的基础转换矩阵,不仅从统计角度分析是可行的;而且从应用角度分析,前者也具有相关结果一致性好,性状标准化合理,相关矩阵不会出现不正定性,年份之间可保证参与距离分析的性状完全一致,D~2估测结果一致性及聚类分析结果相符率高等优点.最长距离法的聚类范围大,并类合理且灵敏度高,聚类结果实用价值高,建议以表型相关矩阵(P)—主成份转换(C)—欧氏距离(E)—最长距离法(L).即PCEL法,作为棉花杂交亲本距离估测与聚类分析的适宜方法.     

不同取样间距农田土壤全量养分空间变异特征研究

以三种取样间距(100m、50m、25m)进行网格取样,对土壤有机质、全量氮磷进行空间变异性分析。结果表明:土壤有机质与全氮含量处于较低水平,全磷含量处于中等水平。全氮的变异系数随不同间距变化幅度较小,有机质与全磷的变异系数随着取样间距增加而减小.取样间距对合理取样数目具有一定的影响,合理取样数目分别为:有机质(24)、全氮(34)、全磷(10).土壤全量养分的空间变异性主要受结构因素影响,随机因素影响较弱,但不同取样间距对全量养分空间变异规律影响不明显;对于全量养分100m的取样间距就可以满足干旱区农田土壤样品的精度要求。