高校后勤文化建设的现状及对策探讨——以华中农业大学后勤文化建设为例

高校后勤文化是高校校园文化的重要组成部分,能有效发挥高校后勤的育人功能,引领和推动学校后勤事业的科学发展。立足华中农业大学后勤文化建设实际,总结高校后勤文化建设的成果,分析存在的问题,提出和谐后勤文化建设的思路。     

一种导航接收机启动策略的优化方案

首次定位时间（TTFF）是导航接收机快速定位能力的重要指标之一，而首次定位时间和导航接收机的冷、温、热启动策略密切相关。基于我国自主研发的北斗卫星导航系统（BDS），根据其特点，提出一种优化启动策略。该启动策略充分利用接收机的硬件资源，合理分配使用各个通道进行卫星信号的搜索，更加充分的使用已知信息，缩小接收机搜索范围和增加捕获卫星信号的成功率。实验结果说明该启动策略可有效缩短导航接收机的首次定位时间。     

Analysis of leaf shedding and dry matter recycling in sweetpotato

During a normal growing season, sweetpotatoes shed a substantial number of leaves (Somda and Kays, 1990b). To ascertain the potential cost of leaf loss to the plant, the sequential loss of leaves over the entire growing season was monitored and related to losses of dry matter and individual elements when leaf shedding was induced via leaf shading. The number of leaves produced increased as the season progressed, but missing leaves outnumbered by 21% those remaining on the plant by the end of the growing season. Average dry weights of individual leaves increased progressively to a maximum 14 weeks after planting, and then declined until harvest. After the 6th week, leaf area decreased relative to plant dry weight for the remainder of the growing season. Mature leaves remobilized nearly 37% of their total dry matter prior to abscission; the remaining 63% was lost from the plant, representing an estimated dry matter loss of approximately 2.8 MT/ha during the growing season. A significant portion of P, K, and Mg that had accumulated in mature leaves was recycled into the plant prior to abscission. However, remobilization of Ca, Fe, Zn, Mn, B, Na, and Al was not significant. Leaf shedding in field populations of ‘Jewel’ sweetpotatoes was extensive, and while significant dry matter was recycled out of the leaves prior to abscission, leaf drop represented a substantial loss of P, K, and Mg and dry matter from the crop.     

北京市顺义区畜牧业发展问题的思考

对北京顺义区畜牧业现状进行了调研,总结顺义区畜牧业发展的经验,分析其面临的新挑战和新机遇,对如何建设都市型现代畜牧业提出对策和建议。     

Chronology of plaggic deposits; palynology,radiocarbon and optically stimulated luminescence dating of the Posteles (NE-Netherlands)

Plaggic agriculture was the dominant land use system on Pleistocene sandy soils in Northwest Europe before the introduction of chemical fertilizers. In the today's landscape plaggic deposits are still recognizable as characteristic soils and landforms, related to this historical land use system. They are also important constituents of the soil archives in Northwest Europe. In preliminary studies of plaggic anthrosols, the reconstruction of the development of the plaggic deposits was based on palynological and historical data and radiocarbon dates. Disagreement appeared between palaeopedological and historical explanation of the evolution of plaggic anthrosols. Application of OSL dating improves the knowledge of chronology of plaggic deposits. The soil organic matrix, including pollen grains, consists of a complex mix of compounds of different ages and sources. Pollen diagrams of plaggic anthrosols show a palynological registration of the Late Holocene landscape evolution, but the palynological signal is not consequently correlated with the age of the plaggic sediments. An older soil organic matrix is suspended in the voids of a younger mineral soil skeleton.     

Evaluation of unconstrained and constrained mathematical functions to model girth growth of rubber trees (Hevea brasiliensis) using young age measurements

No attempt has been made to date to model growth in girth of rubber tree (Hevea brasiliansis). We evaluated the few widely used growth functions to identify the most parsimonious and biologically reasonable model for describing the girth growth of young rubber trees based on an incomplete set of young age measurements. Monthly data for girth of immature trees (age 2 to 12 years) from two locations were subjected to modelling. Reparameterized, unconstrained and constrained growth functions of Richards (RM), Gompertz (GM) and the monomolecular model (MM) were fitted to data. Duration of growth was the constraint introduced. In the first stage, we attempted a population average (PA) model to capture the trend in growth. The best PA model wasfitted as a subject specific (SS) model. We used appropriate error variance-covariance structure to account for correlation due to repeated measurements over time. Unconstrained functions underestimated the asymptotic maximum that did not reflect the carrying capacity of the locations. Underestimations were attributed to the partial set of measurements made during the early growth phase of the trees. MM proved superior to RM and GM. In the random coefficient models, both Gf and G0 appeared to be influenced by tree level effects. Inclusion of diagonal definite positive matrix removed the correlation between random effects.The results were similar at both locations. In the overall assessment MM appeared as the candidate model for studying the girth-age relationships in Hevea trees. Based on the fitted model we conclude that, in Hevea trees, growth rate is maintained at maximum value at t0, then decreases until the final state at dG/dt ≥ 0, resulting in yield curve with no period of accelerating growth. One physiological explanation is that photosynthetic activity in Hevea trees decreases as girth increases and constructive metabolism is larger than destructive metabolism.     

烟叶不同生育期病虫害防治要点分析

充分了解和掌握病虫害发生规律及传染途径,做到防重于治,科学、合理、安全使用农药,才能在病虫害防治方面取得明显效果。     

Artificial soil-like bodies of a river valley and their evolution in an urban environment (Based on the example of the Moscow River valley)

Technogenic soil-like bodies and raw soils on technogenic sediments in the valley of the Moscow River in the city territory were investigated. Soil destruction and the accumulation of techogenic sediments, as well as their remediation, result in the formation of soil-like bodies called replantozems. Spontaneous overgrowth and the formation of raw soils that gradually evolve into mature urban soils result in soils called urbanozems. It is shown that the best foundation for replantozems in river valleys is in situ alluvium with relatively favorable physical and physical-chemical properties.     

Canine CYP2B11 metabolizes and is inhibited by anesthetic agents often co-administered in dogs

Baratta, M. T., Zaya, M. J., White, J. A., Locuson, C. W. Canine CYP2B11 metabolizes and is inhibited by anesthetic agents often co-administered in dogs. J. vet. Pharmacol. Therap. 33 , 50–55.
Medetomidine is a well-established sedative and analgesic for dogs and cats. As a premedicant for anesthesia regimens that also include other agents, medetomidine can also provide a dose-sparing effect. While there are likely several reasons for the dose-sparing effect of medetomidine, the role of metabolic drug–drug interactions at the single enzyme level has not yet been examined. Using a panel of individually expressed canine cytochromes P450 cloned from beagle liver, this report demonstrates that medetomidine is an extremely potent CYP2B11 inhibitor (IC₅₀ < 10 n m ) and that ketamine and midazolam are CYP2B11 substrates with high intrinsic clearances. These in vitro findings suggest that under some circumstances, medetomidine (i.e. 'perpetrator') may inhibit the metabolic clearance of some high metabolic clearance drugs (i.e. 'victims') with which it is commonly co-administered via the CYP2B11 pathway. However, as the dose-sparing effect of medetomidine premedication commonly results in anesthetic dose reduction, any increased plasma concentrations of victim drugs caused by medetomidine would still be lower than if no dose reduction had been made. Further studies are needed to characterize whether medetomidine possesses the potential to cause pharmacokinetic interactions. In conclusion, the ability of recombinant P450s to define canine-specific drug clearance pathways and P450 inhibitors should prove useful in identifying drug combinations that may require dose adjustments in dogs.