论农业图书情报工作的双效益

根据农业生产、科研和教学的不同特点,分析了各种读者群体对农业图书情报的利用情况,论述了农业图书情报工作的社会效益和经济效益及其关系。     

莱芜市发展新材料产业化基地的经验与对策

加快国家新材料产业化基地的建设是提升我国产业竞争力,实施可持续发展战略的重要组成部分.本文对莱芜国家新材料产业化基地建立两年来的发展情况及取得的经验进行了分析,提出了加快新材料产业化基地建设的政策和措施.     

社会力量参与公共图书馆建设探讨

指出公共图书馆要满足社会公众日益增长的精神文化需求,使图书馆服务效益最大化,需要社会各界积极参与,以弥补政府投入图书馆事业的人力、财力之不足。总结社会力量参与图书馆建设的已有模式,探讨社会力量参与图书馆建设的作用,并结合大量实例说明其具体途径,以为相关研究和实践提供借鉴。     

Altered trends in carbon uptake in China's terrestrial ecosystems under the enhanced summer monsoon and warming hiatus

The carbon budgets in terrestrial ecosystems in China are strongly coupled with climate changes. Over the past decade, China has experienced dramatic climate changes characterized by enhanced summer monsoon and decelerated warming. However, the changes in the trends of terrestrial net ecosystem production (NEP) in China under climate changes are not well documented. Here, we used three ecosystem models to simulate the spatiotemporal variations in China''s NEP during 1982–2010 and quantify the contribution of the strengthened summer monsoon and warming hiatus to the NEP variations in four distinct climatic regions of the country. Our results revealed a decadal-scale shift in NEP from a downtrend of –5.95 Tg C/yr² (reduced sink) during 1982–2000 to an uptrend of 14.22 Tg C/yr² (enhanced sink) during 2000–10. This shift was essentially induced by the strengthened summer monsoon, which stimulated carbon uptake, and the warming hiatus, which lessened the decrease in the NEP trend. Compared to the contribution of 56.3% by the climate effect, atmospheric CO₂ concentration and nitrogen deposition had relatively small contributions (8.6 and 11.3%, respectively) to the shift. In conclusion, within the context of the global-warming hiatus, the strengthening of the summer monsoon is a critical climate factor that enhances carbon uptake in China due to the asymmetric response of photosynthesis and respiration. Our study not only revealed the shift in ecosystem carbon sequestration in China in recent decades, but also provides some insight for understanding ecosystem carbon dynamics in other monsoonal areas.     

Climate and litter C/N ratio constrain soil organic carbon accumulation

Soil organic carbon (SOC) plays critical roles in stabilizing atmospheric CO₂ concentration, but the mechanistic controls on the amount and distribution of SOC on global scales are not well understood. In turn, this has hampered the ability to model global C budgets and to find measures to mitigate climate change. Here, based on the data from a large field survey campaign with 2600 plots across China''s forest ecosystems and a global collection of published data from forested land, we find that a low litter carbon-to-nitrogen ratio (C/N) and high wetness index (P/PET, precipitation-to-potential-evapotranspiration ratio) are the two factors that promote SOC accumulation, with only minor contributions of litter quantity and soil texture. The field survey data demonstrated that high plant diversity decreased litter C/N and thus indirectly promoted SOC accumulation by increasing the litter quality. We conclude that any changes in plant-community composition, plant-species richness and environmental factors that can reduce the litter C/N ratio, or climatic changes that increase wetness index, may promote SOC accumulation. The study provides a guideline for modeling the carbon cycle of various ecosystem scales and formulates the principle for land-based actions for mitigating the rising atmospheric CO₂ concentration.     

Rock-salt and helix structures of silver iodides under ambient conditions

Many different phase structures have been discovered for silver iodides. The β and γ phases were found to be the most common ones at ambient conditions, while the rock-salt phase was found to be stable under pressures between 400 MPa and 11.3 GPa. Recently, the α phase was demonstrated to be stable under ambient conditions when the particle sizes were reduced to below 10 nm. However, no other phase has been reported to be stable for silver iodides under ambient conditions. Rock-salt and helix structures have been found to be stable under ambient conditions in this study. The structures have been characterized by elemental mapping, Raman scattering, and high-resolution transmission electron microscopy. The stabilities of these structures were also confirmed by molecular dynamics and density functional theory.     

太极拳练习对少儿体质健康影响的研究

以太极拳练习史在1年以上的115名少儿为实验对象,并随机抽取120名没有太极拳练习史的少儿为对照组,观察太极拳练习对少儿体质健康的影响。结果显示,在某些身体素质和身体机能方面差异显著。结果表明,太极拳练习对少儿的体质健康有促进作用。     

"拟剧理论"之于旅游管理应用型人才培养的启示

旅游管理专业毕业生的实际应用能力达不到市场预期的主要原因在于学习过程中学生积极性不够,实践教学效果不佳;从而出现了旅游管理专业毕业生普遍存在眼高手低的现象.拟剧理论将舞台表演的思想引入到社会活动,师生课堂拟剧对于旅游管理应用型人才培养可以起到积极的指导意义.     

Exploratory Analysis of a Blended-learning Course Redesign for Developmental Writers

This quasiexperimental investigation describes the relative effects of a technology-driven course redesign on retention and achievement in a developmental writing program at a large, urban community college in the southwest United States. The new program focused on student learning and included online as well as face-to-face components that allowed students to complete the program in half the usual time in most cases. On average, students enrolled in the new program had lower placement test scores compared to students in the old program, but the gap was closed in the subsequent test and English course. Details of the redesign and challenges to conducting educational research and data analysis in community colleges are provided for other 2-year colleges considering course redesigns intended to impact student success.