Age estimation of different tree species using a special kind of an electrically recording resistance drill

The determination of tree age is an important issue for urban green planning, forestry and dendrology; finding non-destructive and quasi-non-destructive methods for this purpose is of great theoretical and practical importance. The resistance drilling method is quasi-non-destructive because the average diameter of an opening that remains after drilling does not exceed 3 mm. Do electrically recording resistance drills allow precise assessment of tree age? The aim of this study is to assess the accuracy of determining the number of tree rings based on an examination of this special kind of drilling resistance profiles for three tree species, the pine Pinus sylvestris L., the oak Quercus robur L., and the birch Betula pendula ROTH. In 2015 and 2016, 15 pine trees, 15 oak trees, and 15 birch trees were randomly selected. For each studied tree, a measurement was conducted using the electrically recording resistance drill IML-Resi E400 with a flat-tipped 1.5/3 mm steel needle (research sample), and an increment core was taken (reference sample). The drill used was not a real Resistograph^®. The analysis of the E400-profiles underestimated the number of tree rings; the mean bias error (MBE) values were –6.5, –2.5, and –6.0 years for pine, oak, and birch, respectively. The proportion of investigated trees with less than five years difference between the research and reference samples varied from 38.4 (birch) to 66.7 (oak) percent. The accuracy of tree age determination was lowest for birch and highest for oak. The binomial generalised linear model (GLM) revealed that the most accurate tree age assessments were obtained from tree rings wider than 2 mm. The measurements clearly showed that the electrically recording resistance drill IML-Resi E400 enables a quick, although approximate, tree age assessment. Future research should concentrate on electronically regulating and recording drills, providing a higher spatial and signal resolution, and a stronger correlation to wood density.     

智慧图书馆微观知识生态系统运行机理研究

伴随多元化时代的来临,用户的知识需求日益多元化、专业化,对图书馆服务提出了新的挑战。对智慧图书馆微观知识生态系统运行机理的研究,能够为新型知识服务提供理论基础,保障知识资源进行有效的优化整合,实现服务升级。文章在简要分析智慧图书馆微观知识生态系统四大要素的基础上,着重从社会发展、技术进步,知识富集、优化调整和需求驱动、服务升级三方面探讨其形成动因,重点分析智慧图书馆微观知识生态系统的生命周期,最后从合作、循环和保障三方面探讨其运行机理。     

利用GGE双标图分析花生品质性状的基因型-环境互作

花生品质性状的稳定性和基因型-环境互作研究，可为花生品质育种及不同生态区域花生品种的选择提供参考依据。本研究利用GGE-biplot工具，对我国黄淮海花生主产区16个花生品种两年间的品质性状进行了综合分析，包括含油量、油酸、亚油酸、棕榈酸和蛋白质含量等。结果显示，5个品质性状均有较高的GGE总变异值（主成分因素PC1和PC2变异的总和），变幅在61.5%-79.9%之间，以含油量的GGE变异值最低，为61.5%，油酸含量的GGE变异值最高，为79.9%。16个花生品种2年间部分品质性状表现较为一致，其中濮花9519的含油量表型值波动最小，山花9号的亚油酸含量表型值波动最小，开农49是油酸含量表型值最为稳定的品种，天府23号是棕榈酸含量和蛋白质含量表型值最为稳定的品种。初步明确了徐州和濮阳分别适合高油花生和高油酸花生种植，确定了不同生态类型试点下较适合种植的品种，为花生品种推广应用提供了参考。     

Differential regulation on C5 expression in goose versus mammals by glucose/palmitate provides a potential protection for goose fatty liver

Goose fatty liver is a specific type of nonalcoholic fatty liver that is protected from harmful effects associated with severe steatosis. Our previous findings suggest that suppression of the complement C5 may be relevant, but the mechanism is unclear. Therefore, in this study, we first verified the expression pattern of complement genes (including C5) during goose fatty liver formation and then determined the liver fat content and fatty acid composition by high-performance liquid chromatography (HPLC), followed by selecting the differential metabolites to treat HepG2, goose and mouse primary hepatocytes, aiming to explore the mechanism of C5 and inflammation suppression in goose fatty liver. The data confirmed the suppression of complement genes (including C5) in goose fatty livers. Moreover, fat content was significantly higher in fatty liver versus normal ones, with oleic acid and palmitic acid dominantly accounting for the difference. In line with this, high concentration of palmitate led to down regulation of C5 expression in goose primary hepatocytes whereas upregulation in mouse primary hepatocytes and HepG2 cells. In conclusion, regulation on C5 expression by fatty liver related factors including high level of palmitic acid may contribute to the protection of goose liver from severe hepatic steatosis.     

Essential Factors and Sustainable Development of Green Agriculture

This paper discussed the definition and essential factors of green agriculture, including green ecological environment, green material energy input, application and the popularization of green agricultural technology, the green behavior of worker, green policy regulations guarantee, fund support, supply and the production of green agriculture products, as well as the concept of green agriculture, structural mechanism and function. And finally existing problems in present green agriculture and five suggestions of green agricultural sustainable develonment were proposed.     

脂肪细胞膜免疫降脂的研究

本文综述了利用脂肪细胞膜免疫技术进行畜禽脂肪代谢研究的成果，其技术路线主要包括试验途径和方法、免疫机理、降脂效果及特异性脂肪膜蛋白的研究启示，从而为脂肪细胞膜免疫降脂试验提供成功的范例和科学的依据，并开辟降低脂肪、提高瘦肉率研究的新领域。     

感染白粉病小麦叶片细胞的超微变化

小麦感染白粉病菌后,叶片叶绿体肿胀,双层膜不完整或消失,基粒片层排列疏松紊乱,细胞中出现许多由单层膜围成的大小不等的空胞和类似纤维状的膜状物,细胞核膜消失,质壁分离.     

哺乳动物卵母细胞发育机理的研究进展

卵母细胞的成熟过程是一个复杂的减数分裂过程，许多分子参与了这个过程的调控，本文就卵母细胞成熟抑制因子（OMI）、成熟促进因子（MPF）、生长分化因子（GDF）、微管辅助蛋白（MAP）、激素、Ca^2 及钙调素等对卵母细胞发育调控机理作一综述。     

含蜡原油管道蜡沉积研究进展

蜡沉积会减少管道的有效内径，增大输送压力，降低管道的输送能力，增加清管频率，甚至造成蜡堵事故。介绍了国内外有关析蜡的热力学模型、蜡沉积机理及蜡沉积的动力学模型的研究进展状况，提出了一些研究建议。