十四五时期河北省农村生活污水治理策略的思考

农村生活污水治理是农村人居环境整治的重要内容,是实施乡村振兴战略的重要举措,是全面建成小康社会的内在要求。本文在调研和调查所得数据的基础上,分析总结了“十三五”期间河北省农村生活污水治理工作中存在的问题。针对存在的问题,建议根据各地实际情况实行差异化管控,并从八个方面对“十四五”期间河北省农村生活污水治理工作提出合理化意见和建议。     

中英涉农工程类人才培养模式与机制对比研究

涉农工程类专业是依托农业工程和机械工程两大学科,服务于农业发展,为农业现代化培养专门的工程类人才的工程技术学科专业。本文简要介绍了英国工程类人才培养标准,深度关联分析了英国教育学位体系与工程类人才、教育课程体系与工程专业能力的对应关系。在此基础上,以中国农业大学和英国哈珀亚当斯大学为例,系统对比研究了中英农业工程和机械工程专业大学本科人才培养模式、培养目标和课程体系等。研究结论对于高等教育革命性变化的新形势下,我国探索新的教育培养模式与机制,助力新工科建设具有重要意义。     

Determination of duration of immunity of calves vaccinated with the Theileria annulata schizont cell culture vaccine

Bovine tropical theileriosis caused by Theileria annulata is a serious haemoprotozoan disease of cattle affecting exotic cattle, their crossbreeds and young indigenous calves. Cell culture vaccines have been developed and used effectively in various countries for the control of this disease. However, the duration of immunity provided by these vaccines is poorly understood. The present experiments were planned to study the duration of immunity in animals after vaccination with the T. annulata (Hisar) schizont cell culture vaccine. Two groups of calves were vaccinated and challenged after a period of 3 and 6 months, respectively. There was no fever in any of the vaccinated calves after challenge. However, the vaccinated animals exhibited mild to moderate enlargement of lymph nodes and parasitological reactions. The parasitological reactions were very mild in calves challenged after 3 months and moderate in calves challenged after 6 months. There was a mild but significant decrease in the haematological values of calves after challenge. A significant rise in the anti-theilerial antibody titres was observed in all calves after vaccination, which increased further, by many folds after challenge. On the other hand, all the challenge control calves showed symptoms of acute theileriosis and died. The observations suggested that the T. annulata (Hisar) schizont cell culture vaccine provided immunity in vaccinated animals for at least 6 months in the absence of field tick challenge. However, there was some decline in immunity after 6 months, if the animals are not exposed to ticks during this period.     

鲫鱼耳石日轮研究

对鲫鱼仔、幼鱼及成鱼的耳石研究表明，鲫鱼耳石的第１日轮在孵化后２４～４８ｈ出现，以后每天形成１轮。耳石的轮纹数（Ｎ）和日轮数（Ｄ）的关系为Ｎ＝Ｄ－１．１４６。耳石平均长径和体全长成直线相关。鲫鱼耳石在发育过程中经历了不同形态的变化，增厚较慢，直到孵出后第４０天，不经研磨，其轮纹仍清晰可数，是研究鱼类耳石形成机理以及其他相关研究的好材料。微耳石出现较晚，星耳石是研究鲫鱼耳石的首选材料。本文还对早期耳石的制备方法进了探讨。     

基于YOLOV4模型的果园樱桃实时检测研究

为解决在自然环境下对樱桃不同生长时期的状态监测受环境影响存在目标识别困难、检测准确率低的问题,提出了一种基于CSPDarknet53改进的卷积神经网络樱桃分类检测模型。经典YOLOV4所使用的特征提取网络层数较深,能够提取更高级的抽象特征,但是对目标局部感知能力较弱,通过在CSPDarknet53网络结构上融合CBAM注意力机制,增强了目标局部特征感知能力,进一步提升目标检测精度,其特征提取和目标检测能力优于原算法,调整特征提取网络的特征层输出,将第三层输出变为第二层输出以增加小目标语义信息的获取,利用k-means算法优化先验框尺寸以适应樱桃目标大小,并进行了消融实验分析。结果表明,改进的YOLOV4樱桃检测模型模型的平均精度达到了92.31%,F1分数达到了87.3%,优于Faster RCNN、YOLOV3和原来的YOLOV4算法,检测速度为40.23幅·s^-1,适用于自然环境下的樱桃监测,为实现果园水果生长状态自动监测提供了理论和技术基础。     

甘蓝型油菜(CMS)优质恢复系的改良方法研究

采用4种不同方法,对甘蓝型油菜(CMS)恢复系进行品质和性状改良。结果表明,杂种一代×品种间改良的恢复系生长势强、配合力高;利用多亲本复合杂交,子代的选择广泛,选育优质恢复系容易;而恢复系×恢复系、恢复系×品种只改良了恢复系的单一性状,配合力一般。     

Use of apple pomace as a source of dietary fiber in cakes

Dried and powdered apple pomace was passed through 30, 50and 60 mesh sieves to get pomace of varying particle size. Blends wereprepared by mixing 5, 10 and 15 percent pomace from each of the threeprticle sizes with wheat flour. The blends were evaluated for cake. Batterviscosity increased with increasing pomace level and decreasing particle size. Specific gravity and pH of the batter decreased with increasing pomacelevels. Cake weight, shrinkage and uniformity index increased withincreasing pomace levels, whereas, cake volume and symmetry indexshowed a reverse trend.     

Non-escaping frost tolerant QTL linked genetic loci at reproductive stage in six wheat DH populations

Reproductive stage frost poses a major constraint for wheat production in countries such as Australia.However,little progress has been made in identifying key genes to overcome the constraint.In the present study,a severe frost event hit two large-scale field trials consisting of six doubled haploid(DH)wheat populations at reproductive stage(young microspore stage)in Western Australia,leading to the identification of 30 robust frost QTL on 17 chromosomes.The major 18 QTL with the phenotype variation over 9.5%were located on 13 chromosomes including 2 A,2 B,2 D,3 A,4 A,4 B,4 D,5 A,5 D,6 D,7 A,7 B and7 D.Most frost QTL were closely linked to the QTL of anthesis,maturity,Zadok stages as well as linked to anthesis related genes.Out of those,six QTL were repetitively detected on the homologous regions on 2 B,4 B,4 D,5 A,5 D,7 A in more than two populations.Results showed that the frost damage is associated with alleles of Vrn-A1 a,Vrn-D1 a,Rht-B1 b,Rht-D1 b,and the high copy number of Ppd-B1.However,anthesis QTL and anthesis related genes of Vrn-B1 a and Ta FT3-1 B on chromosomes 5 B and 1 B did not lead to frost damage,indicating that these early-flowering phenotype related genes are compatible with frost tolerance and thus can be utilised in breeding.Our results also indicate that wild-type alleles Rht-B1 a and Rht-D1 a can be used when breeding for frost-tolerant varieties without delaying flowering time.