东风454拖拉机前驱动桥下端盖漏油原因分析及改进措施

通过现场调查和结构分析,指出东风454拖拉机前驱动桥下端盖漏油原因是有零件损伤和结构设计上的缺陷共同造成的,在提出了不同的改进措施同时,并进行了可行性和成本对比分析。     

山药整地机械化作业技术规范

从作业条件、作业准备、作业方法等方面，介绍山药整地机械化作业技术的要点，论述其整地质量要求及相关参数计算方法，为山药种植产业的规范化及扩大化提供参考。     

Moodle平台在虚拟机VmWare下的实践与应用

Moodle平台是一种基于开源PHP技术开发的网络学习平台,现通过虚拟机Vm Ware软件下安装网络操作系统来实现Moodle平台的发布,重点对PHP、Fast CGI以及IIS进行重新配置,从而实现本机与虚拟机之间相互访问,达到Moodle平台下的资源共享和信息交流的目的。     

基于正交试验的花生种养结合栽培方式研究

种养结合是农业循环经济发展的重要措施之一。通过正交试验设计,分析了不同种植密度、复合肥用量、腐熟干粪用量对花生生长发育及产量的影响。分析结果表明:1)三因素中高钾复合肥用量对花生的生长发育及产量影响最大。2)13-10-20高钾复合肥用量为300kg/hm2的处理组合普遍表现出植株较高、分枝数较多、单株结果数多等特点。3)产量分析结果显示:最优处理组合为种植密度120 000穴/hm2、高钾复合肥300kg/hm2、腐熟干粪30kg/hm2,同时影响产量大小的因素顺序为:高钾复合肥腐熟干粪种植密度。     

新时期科研院所党建工作的几点思考

阐述了新时期科研单位加强党建工作的重要性,提出了新形势下抓好科研单位党建工作的基本原则,即坚持围绕发展、服务中心,坚持与时俱进、改革创新,坚持以人为本、突出主体,坚持突出重点、务求实效。同时,提出了新时期科研院所党建工作创新的着力点,即在工作思路上、在工作定位上、工作内容上,工作机制上、工作方法上等进行创新。     

Movement and survival of corn rootworm in seed mixtures of SmartStax® insect-protected corn

SmartStax^® insect-protected corn (Zea mays L.) contains genes for six Bacillus thuringiensis (Bt) proteins controlling both lepidopteran pests and the corn rootworm complex (Diabrotica spp.). The properties of SmartStax, particularly the multiple effective modes of action (i.e., each Bt protein provides a high level of control of the target pests with a low probability of cross-resistance among the proteins), have provided the opportunity to add to previously approved structured refuge options by combining the non-Bt refuge seed with SmartStax seed in a seed mix. Seed mixes ensure that a refuge is present in every Bt field, remove concerns about grower compliance with refuge requirements, and provide grower convenience. However, seed mixes could increase the likelihood that larval insects move between Bt and non-Bt plants and vice versa. Assessing the insect resistance management (IRM) value of a seed mix refuge requires an assessment of the amount of larval movement, and the consequences of that movement, for the key target pests. The studies here present such data for control of corn rootworm by SmartStax corn, which contains the rootworm-active protein Cry3Bb1 and the binary protein Cry34Ab1/Cry35Ab1. In a growth chamber experiment, SmartStax was most effective against first instars and significantly effective against second instars, but did not control third instars. In a field study of movement from a heavily infested non-Bt plant onto surrounding plants, a larger percentage of insects successfully dispersed from the infested plant when the surrounding plants were non-Bt plants than when they were SmartStax plants. A paired-plant study showed that few larvae migrated from infested SmartStax plants and survived on nearby non-Bt plants; larvae that migrated from infested non-Bt plants had low survival if the adjacent plants were SmartStax. Replicated field studies of plant-to-plant movement indicated that the non-Bt plants in a 5% or 10% seed mix consistently supported large populations of susceptible insects and represented a productive refuge, whereas the SmartStax plants had few or no survivors. The timing of emergence from seed mix plots containing 5% or 10% non-Bt plants was more similar to that of the non-Bt plots than that of the SmartStax plots. Thus, the available growth chamber and field data indicate that a seed mix of 5% or more will provide an effective refuge for corn rootworm in SmartStax corn.     

学校体育学学科发展历程与相关问题厘定

通过回顾新中国成立以来学校体育学发展的历程，发现这一学科的建立与发展主要呈现出如下特点：学校体育研究领域较为清晰，自身发展比较成熟，并体现出一定的规律性；适应了学科分化的趋势；在教育政策的支持下确立了学科地位；一大批学校体育工作者的不懈努力。通过梳理我国学校体育学研究成果，认为学校体育学是研究与揭示学校体育现象及其运行规律的一门相对独立的新兴学科，其研究对象是学校体育运行过程中的现象与规律。     

The post-ovulatory rise in progesterone is lower and the persistence of oestrous behaviour longer during the first compared with the second cycle of the breeding season in mares

Mares are seasonally polyoestrous breeders. Therefore, the first ovulation of the season, following winter anoestrus, is the only cycle in which mares ovulate without the presence of an old CL from the previous cycle. The objective of this study was to compare the length of oestrous behaviour, and plasma progesterone concentrations during the early post-ovulatory period between mares after the first and second ovulation of the breeding season. Overall, 38 mares and 167 oestrous periods were used in the study. From those, 11 mares were used during the first and subsequent oestrous period to measure and compare the post-ovulatory rise in progesterone concentration, whereas all the mares were used to compare the length of the post-ovulatory oestrous behaviour between the first and subsequent cycles of the breeding season. The persistence of the post-ovulatory oestrus was longer (p < .001) following the first ovulation of the year (median of 52 h) compared with the subsequent ovulations (median of 36 h for second and later ovulations groups; n = 38 mares). The progesterone concentration at any of the four 8 h-intervals analysed (28, 36, 76 and 84 h post-ovulation) was lower (p < .01) following the first versus the second ovulation of the year. By 36 h post-ovulation the progesterone concentration of mares at the second ovulation of the year had passed the threshold of 2 ng/ml (2.1 ± 0.33 ng/ml), whereas in the first cycle it was 1.2 ± 0.13 ng/ml. In conclusion, mares had lower progesterone concentrations in their peripheral circulation and longer persistence of oestrous behaviour following the first ovulation of the year compared with the second and subsequent ovulatory periods of the breeding season.     

超高效液相色谱-串联质谱法测定猪牛组织中甲基盐霉素残留量

建立超高效液相色谱-串联质谱法测定猪牛组织中甲基盐霉素残留量。猪、牛组织中残留的甲基盐霉素,经乙腈溶液提取,硅胶固相萃取柱净化,超高效液相色谱-串联质谱法测定,外标法定量。甲基盐霉素在5 ng/mL～250 ng/mL的浓度范围内呈现良好的线性关系,甲基盐霉素在猪、牛肌肉、肝脏、肾脏、脂肪中的检测限均为2.5μg/kg,定量限均为5.0μg/kg,猪牛肌肉、肝脏、肾脏、脂肪中5.0 ng/g～100 ng/g添加浓度范围内的回收率均值为71.9%～88.4%,批内批间RSD值均<15%。