Spectral signatures of hydrated proton vibrations in water clusters     

Headrick JM  Diken EG  Walters RS  Hammer NI  Christie RA  Cui J  Myshakin EM  Duncan MA  Johnson MA  Jordan KD 《Science (New York, N.Y.)》2005,308(5729):1765-1769

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Conserved genetic basis of a quantitative plumage trait involved in mate choice     

Mundy NI  Badcock NS  Hart T  Scribner K  Janssen K  Nadeau NJ 《Science (New York, N.Y.)》2004,303(5665):1870-1873

A key question in evolutionary genetics is whether shared genetic mechanisms underlie the independent evolution of similar phenotypes across phylogenetically divergent lineages. Here we show that in two classic examples of melanic plumage polymorphisms in birds, lesser snow geese (Anser c. caerulescens) and arctic skuas (Stercorarius parasiticus), melanism is perfectly associated with variation in the melanocortin-1 receptor (MC1R) gene. In both species, the degree of melanism correlates with the number of copies of variant MC1R alleles. Phylogenetic reconstructions of variant MC1R alleles in geese and skuas show that melanism is a derived trait that evolved in the Pleistocene.  相似文献   

新形势下高校困难生资助工作机制探讨     

宋平 《高等农业教育》2003,(2):87-90

本结合新形势下困难生的特点，在原有助学体系的基础上，从8个方面对高校困难生资助工作进行探讨，试图建立一种新的困难生资助工作机制。  相似文献   

养鸡减少饲料浪费十措施     

宋平 《现代农业科技》2005,(19):62

蛋鸡生产总成本中约有60%～70%来自于饲料.据报道,蛋鸡日常生产中浪费的饲料占其耗料量的3%～5%,对于一个2000只鸡的鸡场来说,所浪费饲料的价值相当于1个工人的工资.在目前饲料价位居高不下、养鸡利润不高的形势下,加强饲料管理、减少饲料浪费是增加鸡场收益的一项重要措施.  相似文献   

Feature Recognition Based on Vector Picture     

WANG Tong-qing  HUA Jin  LU Jun  NI Shui-ping 《保鲜与加工》2005,(1):24-27

The technologyof recognition and understanding architecture engineering drawings by computer is a study hotspot in the field that computer isapplied in engineering research. Based on the characteristicof architectural ichnographyand criterionof architectural design fires prevention, the recognizing identification method and main program based on DXF format is proposed. Experimental results show that it has a preferableautomatic recognition results on the architecture ichnography,and effectivelyimproves the work efficiency.  相似文献   

Encryption Algorithm Based on RSA   总被引：1，自引：0，他引：1  

WANG Qian  NI Jian-wei 《保鲜与加工》2005,(1):68-72

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垂枝植物景观美学分析   总被引：1，自引：0，他引：1  

杨柳青  田英翠  宋平  欧阳艳 《安徽农业科学》2007,35(1):92-93

垂枝植物景观美学功能包括完善作用、统一作用、强调作用、识别作用、软化作用、注目作用.从垂枝植物的形姿、色彩、线条、质地、季相变化等方面,分析了垂枝植物的景观形式美,阐述了垂枝植物与园林建筑、山石、水体、其他植物的景观组合美,并论述了垂枝植物景观意境的创造.  相似文献   

新形势下高校特困生资助工作模式探讨     

宋平 《郑州牧业工程高等专科学校学报》2002,22(4):291-294

特困大学生作为高校的一个特殊群体,出现于90年代中期.据国家有关部门1996年的调查统计,在校大学生中有学费、衣、食之忧的人数有近百万,其中特困生占30%.5年后的今天,特困大学生人数和比重呈快速增长趋势,有的高校,特困生的比例已接近于50%.据<中国青年报>最新报道,我国高校特困生数平均达在校学生总数的25%.  相似文献   

不同基因型水稻抽穗后衰老进程的比较研究   总被引：2，自引：0，他引：2  

许卫锋  梁建生  陈云  吕冰  宋平  桑磉 《北方水稻》2003,(4):15-17

本实验对汕优63、J85、老来青等三种不同基因型水稻品种衰老过程中的生理生化指标进行了分析。结果表明,随着叶片衰老进程,剑叶中的叶绿素含量逐渐下降,丙二醛含量逐渐上升,而根系活力在抽穗后一直呈下降趋势。进一步比较三种不同类型水稻叶片的衰老进程,发现:(1)在外界环境一致的情况下,三种水稻在这三个指标上变化明显不同,其中粳稻老来青抗衰老程度最高,而最易衰老的是杂交稻汕优63;(2)汕优63在抽穗后5～10d内衰老最为迅速;(3)根系活力的下降早于叶片中与衰老有关的指标变化。这表明在衰老过程中,根系的衰老先于叶片。  相似文献   

中国青海湖地区草地蝗虫与土壤的关系   总被引：1，自引：0，他引：1  

NI Shao-Xiang  WANG Jie-Chen  JIANG Jian-Jun  ZHA Yong 《土壤圈》2007,17(1):84-89

A growth chamber study was conducted to determine the relationships between the supply of soil available nitrogen （N） and sulfur （S） and canola （Brassica napus） and wheat （Triticum aestivum L. ‘Biggar＇） N and S uptake and yield in three Western Canadian soils. The suitability of one-hour burial with an anion exchange membrane （AEM） was assessed for its utility as a quick test of the available N：S balance in the soil. Canola and wheat were grown on a Luvisolic soil low in available S and on Brown and Black Chernozemic soils low in both available N and S, with different rates and combinations of N and S fertilizers applied. AEM burial was used to assess soil available nitrate and sulfate supply rates after fertilization. Dry matter yield and N and S concentrations in plant tissues were determined after 6 weeks of growth. The soil available N：S ratio determined by AEM burial closely reflected the relative supplies of available N and S as revealed in the N：S ratios of plant tissue dry matter. The highest yields were achieved where the available N：S ratio in soil and plant tissue ranged from 5 to 13. Thus, a one-hour burial of an AEM probe in the field may be a useful tool to quickly test if a balanced N and S supply is present in the soil for optimum crop yield.  相似文献