新时代国有林场改革的若干问题探讨

国有林场是我国生态文明建设的主力军。随着我国城市化建设步伐的不断加速,生态环境问题业日益突出,如何在保护生态环境的同时,加快经济建设的发展,成为当今林业领域的热点研究问题。本文从国有林场改革的意义、公益性国有林场的特点、国有林场改革的思路及建议、国有林场发展的方向及途径、国有林场可持续发展的措施等方面进行了探讨,以期为国有林场的发展提供借鉴。     

基于工作过程的南疆高职院校园艺技术专业农业应用化学教学改革探析

分析了从南疆职业院校园艺技术专业农业应用化学教学中存在的问题,以提高该课程教学要求及园艺技术人才专业人才培养规格为目标,提出了对接教学领域与职业技能、职业素养,改革教学内容、课程体系、优化教学的方法和手段,为提高园艺技术专业服务育人本质,培养更多更好服务地方经济社会发展的高素质、高技能的园艺技术专业人才奠定重要的基础。     

高职食品与药品类专业“基础化学”教学改革与实践

“基础化学”理论和实验教学质量的“高与低”在一定程度上直接关乎高职院校与化学相近专业人才培养的“成与败”。以教学改革为切入点,在“基础化学”教材建设和系列微课的制作及应用2个维度上,探讨提升“基础化学”课程教学质量的具体措施。     

Factors driving natural regeneration beneath a planted urban forest

Cities around the world are investing in urban forest plantings as a form of green infrastructure. The aim is that these plantations will develop into naturally-regenerating native forest stands. However, woody plant recruitment is often cited as the most limiting factor to creating self-sustaining urban forests. As such, there is interest in site treatments that promote recruitment of native woody species and simultaneously suppress woody non-native recruitment. We tested how three, common site treatments—compost, nurse shrubs, and tree species composition (six-species vs. two-species)—affected woody plant recruitment in 54 experimental plots beneath a large-scale tree planting within a high-traffic urban park. We identified naturally regenerating seedling and sapling species and measured their abundance six-years after the site was planted. This enabled us to examine initial recruitment dynamics (i.e. seedlings) and gain a better understanding of seedling success as they transition to the midstory (i.e. saplings). Seedling and sapling recruitment (native and total) was greater in areas with higher canopy cover. The combination of the nurse shrub treatment with compost and species composition (six-species) treatments increased seedling recruitment by 47% and 156%, respectively; however, the nurse shrub treatment by itself decreased seedling recruitment by 5% and native seedling recruitment by 35%. The compost treatment alone had no effect on the total number of recruits but resulted in 76% more non-native seedlings. The sizes of these treatment effects were strongly dependent on whether the forest plantings were in open areas, versus areas with existing tree canopy, the latter condition facilitating recruitment. Our findings therefore suggest that combinations of site treatments, paired with broad canopy tree species, may be most effective for promoting regeneration of native species resulting in more self-sustaining urban forests.     

CRISPR/cas系统及其在家禽上的应用研究进展

CRISPR/cas是一种获得性免疫防御系统,广泛存在于细菌和古细菌中。Strep tococcus pyogenes cas9(Spcas9)作为目前研究最多、最清楚的效应蛋白,因其酶活性高和靶点广而被应用于生命科学各个领域,但Spcas9分子量大、脱靶率高等缺点在一定程度上限制了其应用。随着CRISPR系统技术被深入开发,一些新效应蛋白被发现,本文就CRISPR/cas系统分类、原理、新效应蛋白发现及cas9(S.Pyogenes)多种变构体技术开发在及家禽上的应用进行综述,为相关领域的研究提供参考。     

基于本科生科研能力培养的普通昆虫学课程教学改革探讨

本文从本科生科研能力培养的角度探讨了普通昆虫学理论课、实验课、实习课及考核方式的教学改革,以期促进创新型植物保护人才的培育。     

原油管道改输天然气前的清管实践

为保证原油管道改输天然气后的输气质量和运行安全,必须在管道输气前实施清管。介绍了新疆塔河油田四、六区块4-1计转站至1号联合站原来的原油集输管道改输天然气前的清管方案和清管步骤,分析了其清管效果,指出利用经清管检测达标后的原油管道改输天然气与再建输气管道相比,不仅施工周期短,工艺操作简单,而且还可节约大量的建设资金。     

环境温度和饲粮营养浓度对生长期母兔代谢能利用率的影响

选用6只9周龄新西兰母兔,评定环境温度和饲粮营养浓度对生长期母兔代谢能利用率的影响。试验在密闭式的小动物呼吸测热柜中进行。分别对处于环境温度为20±2℃和30±2℃,采食两种不同营养浓度的试兔进行测试。饲粮营养水平实测值,分别为12.22kJ ME/g和13.49kJ ME/g;粗蛋白质(CP)分别为17.3％和21.6％;中性洗涤纤维(NDF)分别为23.7％和16.5％。结果表明:环境温度影响试兔的能量平衡,它与采食量间存在着显著的相关。20±2℃时,相关系数r=0.798;30±2℃时,相关系数r=0.875。在本试验设计范围内,饲粮营养浓度并不影响代谢能食入量(ME_I),热增耗(HP)和能量平衡(EB)。当环境温度为20±2℃和30±2℃时,表观代谢能转化率(NE/ME)分别为51％和71％;每天每兔每千克代谢体重代谢能维持需要分别为396 kJ和361 kJ。试验结果认为:环境温度影响营养物质消化率(P相似文献   

从矿难报道看转型期媒体的社会功能——以《南方周末》的矿难报道为例

处于社会转型期的中国，媒体有其特殊性：多元化的社会转型需要媒体发挥较为多元化的社会功能。一方面要继续保持党和政府的喉舌功能，另一方面叉要通过舆论监督来建立媒介信任，从而达到建立社会公信力，抢占市场的目的。笔者以《南方周末》的矿难事故报道为对象，分析目前中国媒体所担负的具体社会功能。