Prolonged elevated atmospheric CO2 does not affect decomposition of plant material

Prolonged elevated atmospheric CO₂ might alter decomposition. In a 90-day incubation study, we determined the long-term (9 years) impact of elevated CO₂ on N mineralization of Lolium perenne and Trifolium repens plant material grown at ambient and elevated CO₂ and low- and high-¹⁵N fertilizer additions. No significant differences were observed in style="vertical-align:bottom" width="61" alt="View the MathML source" title="View the MathML source" src="http://ars.els-cdn.com/content/image/1-s2.0-S0038071705001859-si4.gif"> recovery rates between any of the treatments, except an N addition effect was observed for L. perenne (0.4 versus 0.5% style="vertical-align:bottom" width="61" alt="View the MathML source" title="View the MathML source" src="http://ars.els-cdn.com/content/image/1-s2.0-S0038071705001859-si5.gif"> day⁻¹ in high versus low N). The results suggest that elevated CO₂ did not change plant N mineralization in any of the soils, because of a surplus of available N in the fertilized and leguminous systems, and because of insignificant plant responses to elevated CO₂ in the low soil N availability systems.     

论农民分享经济增长的限制性因素及对策

受主客观因素制约，我国农民长期无权、无钱、无力分享经济增长。重新思考农民阶级的政治定位，以土地国有化为突破口．着力破除城乡二元结构；完善农村投融资体制，建立农民教育体系，建立城乡协调发展机制．促进农民全面分享经济增长。     

高职院校学风管理的现状与对策

文章根据高职院校的学风管理现状,提出了一些针对性的改善意见,包括突出学生思想品德教育、完善学风管理体系、协调各部门的工作等。     

北京通州新通国际花园景观设计

通过对北京通州新通国际花园居住区的背景概述、基地分析、设计依据与定位目标分析,提出了项目的设计原则、设计理念和设计方案。认为,设计应以满足居住者的需求为着力点,社区景观规划应遵循＂公共—半公共—私密＂的逻辑递进关系,强调点线面的相互结合统一。     

农林类高校学风问题及建设对策探讨

从学习目的、学习态度、学习纪律、学习方法、学习兴趣、学习氛围等方面提出并分析了农林类高校的学风问题,从提高认识、抓实专业思想教育、深化教学改革、坚持导管结合、加强校园文化建设等方面提出了加强学风建设的思路与对策。     

不同起垄方式对植烟土壤物理特性及烤后烟叶产质量的影响

为了探讨起垄方式与移栽方式对河南省周口市烟区植烟土壤物理特性和烤后烟叶产质量的影响,以筛选适合周口烟区烤烟产质量和土壤物理特性同步提高的起垄与移栽处理组合模式。采用田间试验法,以‘中烟100’为研究材料,依据起垄方式与移栽方式设置龟背型膜上移栽(T1)、龟背型膜下移栽(T2)、中凹型膜下移栽(T3)和中凹型膜上移栽(T4)4个试验处理,研究不同起垄方式对土壤物理特性和烤后烟叶产质量的影响。结果显示,中凹型起垄的单独和复合处理均可以有效地改善土壤的物理特性和提高烟叶的产质量,其中以中凹型起垄配合膜下移栽处理(T3)效果最好。与T1相比,T3处理可以显著提高各土层土壤含水率和总孔隙度,降低土壤容重,明显促进烤后烟叶中化学成分更加协调,上部叶中性致香物质含量较T1提高了15.96%,产量和产值较T1处理显著提高。因此,中凹型起垄膜下移栽处理更有利于改善植烟土壤物理特性和提高烤后烟叶产质量,是最佳种植模式,结果为河南省周口烟区适宜的烟草种植模式提供理论依据。     

我国运动式治污的有限否定及渐进调试

运动式治污实践效能的边界存在于行政主体职责同构和有限社会资源及政策工具选择的困境中。运动式治理在本质上视为以权威和目标责任为基础的环境威权主义的集中体现,具有一定的局限性。在科层化和社会化之间的运动式治理,应该持“有限否定”的价值取向,通过政府纵向有限“脱嵌”和公民横向“再嵌”摆脱路径依赖,构建顺应国家与社会双向运动力量的复合型治理模式,最终实现环境可持续常态化运作机制。     

Preparation of liquid polyesterpolyols from glucose and its methyl derivative

Preparation of liquid polyols from d-(+)-glucose (Glc) and its derivative, methyl--d-glucoside (m-Glc), has been studied. Direct reaction of -caprolactone (CL) with Glc (CL:Glc = 2:1–5:1 in weight ratio) at 150°C using tin(II) 2-ethyl hexanoate (SnEht₂) (series A), in which melted Glc was suspended in CL, resulted in a dark-brown coloration of the reactants. The reaction was accompanied by formation of high molecular weight resins, a pH drop, production of water, and a considerable decrease in the hydroxyl value from the theoretically expected one. In the case of Glc/ethylene glycol (EG)/CL reaction system with SnEht₂ catalyst at 150°C (series B), in which the weight ratio of Glc to EG was fixed at 1:1, Glc dissolved in the EG/CL mixture, but the brown coloration of the reactant mixture still occurred. In this case, the formation of water was enhanced, but the other effects found in series A were suppressed to a considerable extent. In the m-Glc/CL/SnEht₂ reaction system (series C), in which m-Glc reacted with two to five times weight amounts of CL under the same conditions adopted in series A, development of the color, the production of high molecular weight materials and water, and the changes in pH and hydroxyl value were not observed. These results are discussed based on the chemical structural differences: Glc exists mostly in the hemiacetal form, but tautomerizes to the aldehyde, whereas m-Glc is an acetal and is protected from reversion to the aldehyde.     

试论“花香鼓舞”的当代传承

本文通过对“花香鼓舞”的研究,对其未来的发展与传承做出了深入的探究和思索。笔 者认为,“花香鼓舞”的当代传承不应只是动作形式上的传承,更应该是二老艺人的保护,舞蹈演 员及舞蹈编导和对民族文化的继承与发展。     

“样式雷”建筑文化传承的途径研究

在推动民族文化职业教育特色发展的背景下,就高职教育中的古建筑工程技术专业如 何融入“样式雷”建筑文化进行了的分析,并从人才培养目标的制定、课程体系的构建、校园文化 的建设和数字技术的结合几方面对传承的途径给予了阐述。