利用高等数学推导边际分析在经济学中的应用

本文从高等数学的基本理论导数的概念出发，引出了经济管理学中重要的概念边际函数，通过介绍经济科学中常用的函数及大量的实例，探讨了高等数学在经济管理学中的应用，给出了解决这些问题的一般方法。     

基于GIS的东北黑土区土壤侵蚀模数计算

为了监测及评估我国东北黑土区土壤侵蚀现状,在地理信息系统技术的支持下,应用CSLE模型,结合0.5 m分辨率的World View遥感影像,定量估算黑龙江省克山县古城小流域的土壤侵蚀量。结果表明:1)研究区的土壤侵蚀强度为轻度侵蚀,侵蚀区主要集中在该区的西北、东北和中南部地区;2)当坡度<20°时,土壤侵蚀程度较低,当坡度>20°时,土壤侵蚀较严重,此外坡度还能通过影响耕作措施的方式对土壤侵蚀强度产生间接作用,而水土保持措施因子和生物措施因子同样对土壤侵蚀区的分布范围及强度影响较大。研究结果对我国东北地区防治水土流失、减少河流泥沙、改善和恢复黑土肥力具有重要意义。     

拟南芥逆境胁迫诱导表达基因rd29A启动子的克隆与序列分析

以拟南芥基因组DNA为模板,通过PCR扩增得到逆境胁迫诱导表达基因rd29A的启动子片段,将其克隆到pUC19质粒中进行序列分析。结果表明,获得的启动子片段大小为937bp,与已报道的该启动子序列比较,其核苷酸序列同源性为99．8％。     

Research advances of SAR remote sensing for agriculture applications: A review

Synthetic aperture radar (SAR) is an effective and important technique in monitoring crop and other agricultural targets because its quality does not depend on weather conditions. SAR is sensitive to the geometrical structures and dielectric properties of the targets and has a certain penetration ability to some agricultural targets. The capabilities of SAR for agriculture applications can be organized into three main categories: crop identification and crop planting area statistics, crop and cropland parameter extraction, and crop yield estimation. According to the above concepts, this paper systematically analyses the recent progresses, existing problems and future directions in SAR agricultural remote sensing. In recent years, with the remarkable progresses in SAR remote sensing systems, the available SAR data sources have been greatly enriched. The accuracies of the crop classification and parameter extraction by SAR data have been improved progressively. But the development of modern agriculture has put forwarded higher requirements for SAR remote sensing. For instance, the spatial resolution and revisiting cycle of the SAR sensors, the accuracy of crop classification, the whole phenological period monitoring of crop growth status, the soil moisture inversion under the condition of high vegetation coverage, the integrations of SAR remote sensing retrieval information with hydrological models and/or crop growth models, and so on, still need to be improved. In the future, the joint use of optical and SAR remote sensing data, the application of multi-band multi-dimensional SAR, the precise and high efficient modeling of electromagnetic scattering and parameter extraction of crop and farmland composite scene, the development of light and small SAR systems like those onboard unmanned aerial vehicles and their applications will be active research areas in agriculture remote sensing. This paper concludes that SAR remote sensing has great potential and will play a more significant role in the various fields of agricultural remote sensing.     

中草药提取物对蔬菜两种采后病原真菌的抑菌活性研究

以灰葡萄孢菌和链格孢菌为供试病菌,采用生长速率法和培养板连续稀释法在离体条件下研究了木香、决明子等16种中草药提取物抑菌活性,对其效果较好的中草药提取物最小抑菌浓度(MIC)和最小杀菌浓度(MFC)进行了初步确定。试验结果显示,北豆根与黄柏在质量浓度为10.0mg/mL时,对两种病原真菌菌丝生长的抑制率均高于60%。它们对灰葡萄孢菌的最小抑菌浓度MIC依次是12.5,25mg/mL,最小杀菌浓度浓度MFC分别为:25,50mg/mL;对链格孢菌的MIC分别是6.25,12.5mg/mL,MFC都高于MIC两倍,分别是12.5,25mg/mL。     

Genetic variability and molecular evolution of arabis mosaic virus based on the coat protein gene sequence

Arabis mosaic virus (ArMV) is an important pathogen infecting a wide range of plant species worldwide. In the present study, we carried out exhaustive phylogenetic analyses based on the coat protein (CP) sequence of ArMV isolates originating from different host plants and geographic regions. Maximum-likelihood reconstruction revealed the presence of three distinct, well-supported phylogroups. BaTS analyses indicated that the diversity of ArMV isolates may be correlated with both host plant and geographic origin. Moreover, population genetic analyses showed significant differences in the level of genetic diversity among variants within ArMV that originated from rhubarb plants, as expected by quasispecies. Further analysis revealed that both selection and recombination are shaping the population structure of ArMV. In total 14 groups of residues were detected as coevolving for different amino acid properties.     

Hemagglutinins in vegetative tissues of Bengal gram

Hemagglutinating activity was identified in the roots and vegetative tissues of Bengal gram using rabbit erythrocytes. The activity in the roots appears to be similar to that of the seeds in respect to their sugar inhibition property. Seed and root extracts were found to have fetuin inhibitory agglutinating activity, whereas cotyledons showed different sugar specificity. However, 7-day cotyledons and roots from 3 and 7-day plants were also found to have galactose and N-acetyl-D-galactosamine inhibitory activity. Protein profile in different tissues during their developmental stages was analyzed by SDS-PAGE. A major band at 66 kDa was common to all tissues at different stages of their development except 3-day cotyledons where 2 major bands at 22 kDa and 74 kDa were observed. Two prominent bands at 74 kDa and 86 kDa were found along with 60 kDa protein in 3-day old roots whereas a major band at 33 kDa was found in 15-day old roots. Total protein content and specific activity of hemagglutinin were measured. Increase in specific activity with lower protein content was observed in cotyledons of 15-day old plant. Specific activity was eight times higher in the roots and four times more in leaf tissues of 7-day old plants in comparison to 15-day old plants. Stems also showed a significant increase of specific activity (p = 0.013) in 7-day old plants without any significant alteration in the protein content.     

瑞香狼毒粗提取比较与成分分析

主要采用了不同提取液、不同提取液倍数、不同提取方法对瑞香狼毒进行了提取率的研究．同时对不同提取方法所得提取物的成分进行了分析。结果表明：以6倍95％乙醇作为提取液．采用75℃浸泡5d的提取方法提取率高,成分含量多,特别是针对其杀虫效果而言,采用乙醇作为提取液效果更佳。     

双峰驼乳乳铁蛋白的分离纯化研究

试验以阿拉善双峰驼初乳为研究对象,经离心脱脂、酸沉淀去除酪蛋白并用硫酸铵经2次盐析获得乳铁蛋白粗提物,再通过Sephadex G-100凝胶层析进行纯化。利用考马斯亮蓝和SDS-PAGE电泳定性定量检测。结果表明,乳铁蛋白分子量为81．42kD,每毫升驼乳中能提取乳铁蛋白约0．86mg,纯度可达90％以上。     

基于MOD16的锡林郭勒草原14年蒸散发时空分布特征

基于MODIS全球陆地蒸散发产品(MOD16),对锡林郭勒草原近14年蒸散发的年际和年内时空变化规律进行分析,同时探究不同类型草原蒸散发的变化特征。结果表明:(1)2000~2013年研究区蒸散发有波动中缓慢上升的趋势,在175.2~234.5mm间波动,多年年均值达204mm。月蒸散量高值集中在水分充足、气温较高、植被生长旺盛的6~8月份,在7月份达到最大值。(2)锡林郭勒草原多年平均蒸散发的空间格局由东北向西南逐渐减少,植被覆盖度高的区域蒸散量大,近14年来蒸散发的变化有增加趋势的面积大于呈减少趋势的面积,其中呈显著增加的像元主要位于东乌珠穆沁旗北部;减少的地区主要分布在二连浩特、苏尼特右旗及苏尼特左旗西部等。(3)不同草原类型蒸散发量由草甸草原向草原化荒漠、典型草原和荒漠草原逐渐减少。(4)在年际尺度上,在锡林郭勒地区降水是影响蒸散量的更为重要的因素。