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951.
略论信息环境下高校图书馆知识服务   总被引:1,自引:0,他引:1  
韩菲  刘晓 《农业网络信息》2009,(7):48-49,55
本文通过阐述信息环境下知识服务的内涵和特征,详细分析了实现高校图书馆知识服务的对策.  相似文献   
952.
对奶牛产奶性能的5个性状(泌乳量、乳脂率、乳脂量、蛋白率和蛋白量)以及2个重要的次级性状(乳房炎发病率和繁殖力)QTL作图的方法和进展进行综述,并讨论了奶牛QTL定位中存在的问题。  相似文献   
953.
花生籽仁大小相关性状是决定花生产量的直接因素。为发掘与花生籽仁大小相关的QTL,本研究以中花16×J11构建的RIL群体为材料,得到了一张包含289个SSR标记、21个连锁群、覆盖长度为947.3cM的遗传连锁图谱。连续2年对籽仁大小相关性状鉴定表明,各性状在群体中变异广泛,呈典型正态分布,且大部分性状间显著相关。结合本研究构建的遗传图谱,利用WinCart2.5进行QTL定位分析,2年共检测到66个QTL,贡献率为3.23%~33.01%。与籽仁长(SL)、籽仁宽(SW)、籽仁长宽比(LWR)和百仁重(HSW)相关的QTL分别有18、16、18和14个。在这些QTL中,A05染色体上的区间A05A1500-A05A1530同时存在控制籽仁长(qSLA05.1和qSLA05.2)和百仁重的相关的QTL(qHSWA05.1);B06染色体上的区间A06B135-A06B113同时存在控制籽仁宽(qSWB06.2和qSWB06.4)和百仁重相关的QTL (qHSWB06.4),这些稳定存在的主效QTL将为花生产量相关性状的精细定位和分子育种奠定基础。  相似文献   
954.
为了发掘更多玉米C型不育胞质的强恢复系资源,本研究对2份自交系Z16和7250-14-1进行了恢复能力的测定、恢复基因的遗传分析及恢复基因的分子标记定位。结果表明, Z16和7250-14-1对C黄早四、C478、C698-3和CMo17均表现为育性恢复,而对C48-2则均表现为育性部分恢复。通过对玉米CMS-C不同亚组胞质测交鉴定发现, Z16对G48-2、EC48-2、ES48-2、RB48-2及类48-2均表现为不育性保持,而7250-14-1对G48-2、EC48-2、ES48-2表现为育性部分恢复,对RB48-2和类48-2则表现为不育性保持。Z16和7250-14-1对CMS-T不育系均表现为不育性保持,而对CMS-S不育系则均表现为育性部分恢复。遗传分析显示, Z16对C478和C黄早四的育性恢复均受1对基因控制;而7250-14-1对C黄早四及C478的育性恢复分别受1对基因及2对基因控制。利用(C黄早四×Z16)F2、(C黄早四×7250-14-1)F2群体分别对恢复基因进行分子标记定位,其中Z16的恢复基因被定位于标记B-1至第8染色体短臂末端区域,物理距离为494 kb; 7250-14-1的恢复基因被定位于第8染色体短臂的标记B-1和Chr8-86080之间,物理距离为249kb。该研究不仅为玉米CMS-C"三系"配套的生产利用提供了恢复基因资源,也为玉米CMS-C恢复基因的克隆及恢复机制的研究奠定了一定基础。  相似文献   
955.
机械制图测绘对于机械类各专业学生而言,属于重要的实践性教学环节。采用CAI课件作辅助教学手段,演示装配体动画演示、分步分析等,会使讲授效果达到更加理想状态。为此,主要介绍了研究开发的机械制图测绘CAI的目的和研制过程,并对课件基本框架做了简单说明。  相似文献   
956.
办公自动化系统的发展方向是以知识管理为核心的办公自动化系统,知识发现、知识提取是其中重要的技术。基于语义相关性提出了一种知识发现的模型.并根据TextTiling算法给出了其实现方法。  相似文献   
957.
本文调查研究额济纳地区野生动物的种类组成和额济纳蒙古族的传统动物学知识和文化。共记录到野生动物113种,其中鱼类和两栖类各1种,爬行类9种,鸟类74种,兽类28种;国家重点保护动物有19种,占总数的16.8%,其中属国家Ⅰ级保护动物5种,Ⅱ级保护动物14种。额济纳蒙古族对野生动物的生态习性、数量和分布等很了解,对野生动物的传统命名知识也非常丰富,并且具有根据所分布的野生动物名字来命名周围的自然和人文地理实体及人文景观的传统文化。  相似文献   
958.
Research mapping is a method of organising research information as part of a process of formulating a research policy in a specific area. A research mapping project was undertaken in the UK, which aimed to map existing and future research into public and green space, to identify gaps in order to help set priorities for future research, and to develop a freely accessible and searchable database of this research. The mapping was structured around two axes. The first axis was of research themes based on The Value of Public Space but developed further and broken down into sub-themes. The second axis was a typology of green and public space based around Planning and Policy Guidance Note 17 (PPG17) with elaboration from Green Spaces, Better Places. Research dating back to 10 years was collected together with information on recently completed, ongoing and planned UK research. Only research meeting specific quality criteria was included. Some information was also collected at a seminar where attendees from a range of organisations were invited to offer their perspectives on where research priorities should be directed. All the material was analysed and the main trends were identified. Three key cross-cutting themes common to much of the research were identified. These are the general lack of baseline surveys against which to assess progress over time; methodological issues, especially the need to standardise data collection methods and techniques; the classification of social groups, currently considered to be too crude.It was found that most research has been undertaken on physical aspects, such as planning and on biodiversity. Economic values have also been a focus, but on a smaller scale. Social research is quite well covered but very patchy. Management is better covered than maintenance. By far the weakest area represented in the research is health and well-being, both in terms of social groups and types of green space. Priorities for further research were then identified.  相似文献   
959.
The behaviour of sheep, goats and cattle on a shrub and tree savannah in the sub-humid zone of West Africa was studied during the dry (February to May), rainy (June to September) and cool season (October to January). Two mature females per animal species were followed by two observers during 3 days per month and behaviour activities were recorded every 15 min of the daily grazing time. When browsing, the plant name, plant part and plant height reached during prehension were recorded. The distance travelled and the grazing circuits were recorded with a step counter and a Geographic Position System device. The knowledge of farmers concerning appreciated browse species relative to the browse species consumed by animals in the area was also investigated.

During the dry season sheep, goats and cattle spent around 25% of their time browsing and 20%, 16% and 31%, respectively, of their time grazing. During the cool season, goats (17%) browsed more than sheep (7%) and cattle (5%) (P < 0.05). During the rainy season, sheep browsed 20% of the time while cattle spent only 7% of their time browsing, while goats were tied, with no opportunity for browsing. Browsing leaves was the most important part of the browsing activity. During the cool season, browsing height was the same (1.0 m) for cattle and goats, but lower for sheep (0.6 m) (P < 0.05). In the dry and cool season, sheep and goats walked shorter distances than cattle.

The plant species with the highest frequency of consumption were Acacia dudgeoni Craib, Ficus gnaphalocarpa (Miq.) A. Rich, Dioscorea togoensis Knuth, Cordia myxa L., and Manguifera indica L. for sheep and goats and Afzelia africana Sm., Kaya senegalensis (Desv.) A. Juss, Pterocarpus erinaceus Poir. and Dicrostachys cinerea (L.) Wight and Arn. for cattle. Species with a high frequency of citation by farmers were A. africana (92%), K. senegalensis (88%), P. erinaceus (86%), Faidherbia albida A. Chevalier (80%), A. dudgeoni (70%) and F. gnaphalocarpa (69%).

In conclusion, browse species make an important contribution to the diet of ruminant animals in the sub-humid zone and farmers are familiar with the species consumed by ruminant animals.  相似文献   

960.
运用非线性映射方法对国务院西部地区开发领导小组办公室公布的1995年-2004年西部12省区的20个主要经济评价指标进行降维处理后,基于分形理论,研究了各年度的样本点之间的空间分布状态特征的关联维数。结果表明,2000年-2004年的关联维数分别为1.475,1.381,1.300,1.237,1.228,呈现减小的变动趋势,西部12省区之间的发展具有收敛性特征。文章最后讨论了西部12省区之间的区域经济发展收敛特性的指示功能。  相似文献   
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