不同Web时代个性化信息服务的比较研究

基于Internet的个性化信息服务是根据用户的个性需求，为其提供定向化的信息服务。个性化信息服务在不同Web时代表现有所不同，并从低级形态到高级形态逐渐演变，从个性模糊到用户能参与互动，到最终的网人合一，Web在继承革新的基础上，把人从剥离的场景中融入到网人合一的境界，并最终实现，信息由用户产生，用户有针对性地、特色化地利用信息，并享受信息所带来的财富。     

GRP1.8-反义pt4CL1基因对巨尾桉 木质素含量的影响

桉树是桃金娘科桉树属(Eucalyptus）植物的统称,是制浆造纸的主要原料之一,但是桉树中含有大量木 质素,木质素的存在会严重影响纸浆的质量。4-香豆酸颐辅酶A 连接酶(4CL）是木质素单体生物合成的关键酶之一, 抑制4CL 基因的表达,可以有效降低植物中木质素的含量。通过根癌农杆菌介导的叶盘转化法,将形成层定位启动 子GRP1.8 融合的杨树反义4-香豆酸:辅酶A 连接酶基因导入巨尾桉,经卡那霉素筛选和PCR 鉴定,获得9 株转基 因阳性植株。通过4CL 酶活性测定和木质素、纤维素含量的分析,发现转基因组培苗的4CL 酶活性比对照植株下降 了44%,温室转基因幼苗中硫酸木质素含量下降了16%。     

Effects of vegetation type on soil resistance to erosion: Relationship between aggregate stability and shear strength

Soil water erosion and shallow landslides depend on aggregate stability and soil shear strength. We investigated the effect of vegetation on both soil aggregate stability and shear strength (through direct shear tests) in former croplands converted to vegetated erosion protection areas within the context of China's sloping land conversion programme. Four treatments were analysed in plots comprised of (i) 4 year old crop trees, Vernicia fordii, where understory vegetation was removed; (ii) V. fordii and the dominant understory species Artemisia codonocephala; (iii) only A. codonocephala and (iv) no vegetation. Soil samples were taken at depths of 0–5 cm and 45–50 cm. Root length density (RLD) in five diameter classes was measured, soil organic carbon (SOC), hot water extractable carbon (HWEC), texture and Fe and Al oxides were also measured. We found that mean weight diameter after slow wetting (MWD_SW) in the A-horizon, was significantly greater (0.94–1.01 mm) when A. codonocephala was present compared to plots without A. codonocephala (0.57–0.59 mm). SOC and RLD in the smallest diameter class (< 0.5 mm), were the variables which best explained variability in MWD_SW. A significant positive linear relationship existed between MWD_SW and soil cohesion but not with internal angle of friction. As herbaceous vegetation was more efficient than trees in improving aggregate stability, this result suggests that the mechanisms involved include modifications of the cohesive forces between soil particles adjacent to plant roots and located in the enriched in SOC rhizosphere, thus also affecting shear strength of the corresponding soil volume. Thus, vegetation stabilised soil under different hierarchical levels of aggregate organisation, i.e. intra- and inter-aggregate. Our results have implications for the efficacy of techniques used in land conversion programs dedicated to control of soil erosion and shallow landslides. We suggest that mixtures of different plant functional types would improve soil conservation on slopes, by reducing both surface water erosion and shallow substrate mass movement. Planting trees for cropping or logging, and removing understory vegetation is most likely detrimental to soil conservation.     

实用农业多元统计分析系统的开发与应用

MSA1.0是根据农业科研单位数据处理需要开发的实用农业多元统计分析系统。该系统具有功能实用、操作简单、界面简洁友善、数据处理精度高、稳定性好等特点。本文介绍了MSA1.0的结构特点及其主要功能,并通过应用实例说明了其使用方法。     

安徽省皖南地区优质烟叶栽培管理专家系统的研究

以中科院合肥智能所最新研制的智能化农业信息处理开发平台AIP 1.0为系统开发工具 ,科技人员的科研成果、烟农的实际经验和资料知识为基础 ,运用人工智能技术、神经网络技术、多媒体技术、GIS技术、AGENT技术等与专家群经验相结合的方式 ,开发出了适合安徽省皖南地区优质烟叶栽培管理专家系统MESTCM。该系统由知识库、数据库、模型库、信息库、推理机、人机交互等综合而成 ,具有可视化、网络化、知识化、构件化、智能化的特点。该系统的开发可以为科技人员和烟农生产优质烟叶提供一个平台 ,通过该系统还可以帮助烟农做出合理的生产布局和科学决策 ,及时指导烟叶生产 ,进一步提高安徽省烟叶质量     

玉米弯孢叶斑病菌毒素稳定性的研究

玉米弯孢叶斑病菌在Fries培养基上培养20 d左右,菌丝大量生长并紧密交织成团时病原菌即可产生大量毒素。毒素粗提液经高温处理仍具有生物活性,甚至略有增强。该毒素经低温处理后,可保存30 d以上而不失活。经验证毒素原液中的活性成分经光处理10 h不失活,对光具有良好的稳定性。     

酵母双杂交筛选与杨树 Subgroup 4MYB 转录因子相互作用的蛋白质

根据 GenBank中的猪圆环病毒 2 型 ORF2 基因序列、设计合成 2对引物、通过对环介导等温（LAM P）扩 增条件的优化、敏感性、特异性试验、成功建立了猪圆环病毒 2 型 LAM P 诊断方法。 敏感性结果显示、建立的 LAM P 诊断方法最低核酸检测量为 0. 30 pg/ L、而 PCR 诊断方法最低核酸检测量为 30 pg/ L;特异性结果显示、猪圆环病毒 1 型、猪细小病毒、猪伪狂犬病毒、猪繁殖与呼吸综合征病毒、猪瘟病毒的扩增结果均为阴性。 对 95份自然感染病猪样 品的检测结果表明、该 LAM P 方法检测结果与 PCR 检测结果符合率为 95. 8% 。 整个扩增反应可在 30 mi n内完成、结 果肉眼可见、为猪圆环病毒 2型的现场快速诊断提供了一种简便可行的方法、能够满足基层现场快速检疫的需要。     

10种情报学期刊2000～2006年被引统计分析

依据<中国学术期刊文献评价统计分析系统> (V1.0),对10种情报学期刊载文在2000～2006年被引用的情况进行统计分析,客观揭示他们的办刊质量及其影响.     

Nutritional composition of selected green leafy vegetables,herbs and carrots

Six green leafy vegetables and herbs – spinach, amaranth, bengal gram, cauliflower, mint, coriander and carrots – were analyzed for moisture, protein,ascorbic acid, -carotene, total iron, ionizable iron (as % of total iron) in vitro iron (% of total iron), copper, manganese and zinc. Moisture content of the leaves and carrots varied from 75.1 percent (bengal gram) to 95.4 percent (carrot) and protein from 9.83 percent (carrots) to 30.9 (mint) percent. Ascorbic acid, -carotene, total iron and ionizable iron contents were at a maximum in case of bengal gram leaves whereas level of ionizable iron and in vitro iron as a percent of total iron was highest in carrots. Copper, manganese and zinc contents were maximum in spinach.     

大学图书馆应建立健全第二代学科馆员制度

对大学图书馆学科馆员制度的演变过程,及两代学科馆员制度的不同进行了简要的阐述,重点论述了第二代学科馆员的核心能力,及如何建立健全第二代学科馆员制度。