<Emphasis Type="Italic">Mrakia psychrophila</Emphasis> sp. nov., a new species isolated from Antarctic soil     

Xin MX  Zhou PJ 《Journal of Zhejiang University. Science. B》2007,8(4):260-265

The yeast strain （Y18） was isolated from a soil sample collected from Fildes Peninsula, Antarctica. The strain is a psychrophilic yeast with optimum and maximum growth temperatures of 10 ℃ and 18 ℃, respectively. Teliospores were formed after 7 d on malt agar, when the germination of teliospores was observed. Both inositol and D-glucuronate were assimilated. Positive results of the DBB （diazonium blue B） color reaction, urease test, and starch formation were observed. The major CoQ is Qs. All results indicated that Y18 belongs to the genes of Mrakia. The 18S rDNA sequence analyses showed that Y18 is closely related to Mrakiafrigida. DNA-DNA relatedness study, and some biochemistry characteristics indicated that Y18 represents a new species for which Mrakia psychrophila sp. nov. is proposed.  相似文献   

基因工程中工具酶的有关问题解答     

吴举宏 《中学生物教学》2011,(3)

<正>1限制性核酸内切酶是如何命名的?怎样理解其识别序列的特异性和切割位点的特异性?限制性核酸内切酶的命名,目前主要以Smith和Nathans的命名系统为基础,  相似文献   

对“群落的演替”一节教学内容理解的四个把握     

杨京举 《中学生物教学》2011,(6):37

<正>"群落的演替"一节的教学中,教师如何能让学生在客观分析群落演替的过程上正确对待群落演替的概念,准确区分初生演替和次生演替?对以下四个方面的把握很关键。1对群落演替概念的理解要把握住"因演而替的主体过程"人教版新教材中对群落演替的定义为:随着时间的推移,一个群落被另一个群落代替的过程。这一概  相似文献   

例析限制酶切割难题现象     

魏威 《中学生物教学》2011,(3):31-32

<正>近年来,选择合适限制酶对目的基因和质粒进行切割似乎成为高考的一个热点,如江苏、天津等地的高考试题中,多次涉及限制酶切割目的基因和质粒的问题。由于考生对限制酶识别序列及切割点产生的黏性末端认识不清,导致该类试题时常成为难题。这类试题考查的能力主要包括以下几个方面。  相似文献   

查询片段中用户信息记录行为预测研究     

宋筱璇  刘畅 《图书与情报》2023,(1):90-100

信息记录行为在搜索任务的完成过程中,特别是学习相关的搜索情境中,通常被视为信息使用活动重要的外在表征之一。文章开展了一项用户实验,利用查询片段内的搜索活动来预测用户在搜索过程中是否以及何时发生信息记录行为。结果表明：结合用户在内容页面停留时间和活动转移特征变量,预测准确率达到86.9%。而隐马尔可夫模型（HMM）能够有效地对信息记录行为开展实时预测,特别是在用户的首次查询片段内,准确率更高,为76.65%。研究结果为基于搜索活动对用户的信息记录行为开展实时监测提供了有效的方法,有助于支持信息记录行为和搜索任务完成的搜索系统功能及工具的设计与优化。  相似文献   

Length-based vehicle classification in multi-lane traffic flow     

于洋  于明  阎刚  翟艳东 《天津大学学报(英文版)》2011,17(5):362-368

For the realtime classification of moving vehicles in the multi-lane traffic video sequences, a length-based method is proposed. To extract the moving regions of interest, the difference image between the updated background and current frame is obtained by using background subtraction, and then an edge-based shadow removal algorithm is implemented. Moreover, a thresholding segmentation method for the region detection of moving vehicle based on location search is developed. At the estimation stage, a registration line is set up in the detection area, then the vehicle length is estimated with the horizontal projection technique as soon as the vehicle leaves the registration line. Lastly, the vehicle is classified according to its length and the classification threshold. The proposed method is different from traditional methods that require complex camera calibrations. It calculates the pixel-based vehicle length by using uncalibrated traffic video sequences at lower computational cost. Furthermore, only one registration line is set up, which has high flexibility. Experimental results of three traffic video sequences show that the classification accuracies for the large and small vehicles are 97.1% and 96.7% respectively, which demonstrates the effectiveness of the proposed method.  相似文献   

基于个人信用卡消费分析的客户分类指标研究     

耿晨星 《漯河职业技术学院学报》2011,10(1):72-74

随着信用卡业务的蓬勃发展,信用风险成为金融风险的一项重要内容。在加强事后监控进行风险监控的理念下,基于个人信用卡消费分析建立了若干指标,可用于对持卡人的信用进行分类和授信控制。  相似文献   

几种黄山茶叶的红外光谱的双指标序列研究     

张燕飞  叶中胜  汪志伟  徐芸芸 《黄山学院学报》2019,21(3)

  相似文献   

补缀亦成文——浅谈小学习作的“补缀”法     

蒋玲玲 《读与写:教育教学刊》2011,(8):131

"不积跬步,无以至千里;不积小流,无以成江海。"任何一篇习作的基础单位都应先是字、词;然后才是句、段、篇。根据习作教学的序列:一二年级进行的是用词、造句的训练;三四年级进行的是片段训练;而高段应进行简单的篇章训练。只是,习作训  相似文献   

强化单元序列,让班队课的育人价值最大化     

《小学教学参考》2019,(21)

由于很多班主任课程意识淡薄,课程能力有限,在主题班会课程设置中就出现众多泛化的现象,影响了班队课应有的育人效果。结合当下主题班会设计单维、孤立的现状,我们倡导将主题班会的设置从体验、践行和分享交流等单元框架入手,构建出目标、内容、实践和评价一体性的育人达成系统,真正为学生的生命成长服务。提出要依托实践主题,强化单元设计的序列性;依托专业项目,强化单元设计的自主性;依托观念认知,强化单元设计的实践性;依托明确任务,强化单元设计的目标性,让班队课的育人价值最大化。  相似文献