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1.
我国2种多年生野生大豆的染色体研究   总被引:6,自引:0,他引:6  
对我国大豆属Glycine亚属2种多年生野生大豆进行了细胞染色体观察,结果表明:多年生野生在豆-G.tomentella(短绒野大豆、多毛豆)和G.tabacina(烟豆)的染色体均较小,着丝粒很难分辨,染色体间的形态差异不显著;自不同产地的2种多年生野生大豆的染色体组成均为2n=80,无明显变异,与我国一年生野生大豆G.soja的染色体数(2n=40)相比,二者呈整倍关系。  相似文献   

2.
地理场理论的几个问题   总被引:1,自引:0,他引:1  
本文通过对地理场理论研究的回顾与评价,提出了地理场的基本概念,并要分析了地理场的基本特性、基本效应和基本方程,阐明了地理场理论的基本问题与研究意义。  相似文献   

3.
李卫刚 《科技资讯》2009,(29):29-29
网络应用的日益增加及移动办公的特殊需求促进了Web操作系统发展,文章以一个Web操作系统为实例,分析了Web操作系统诞生的背景以及在当下的应用、发展和前景。  相似文献   

4.
首先介绍了FS算法的原理,然后使用了一种将部分失真搜索算法与超立方体码字搜索算法相结合的快速码字搜索算法,并将其应用于G.722.2中.仿真结果表明:与FS算法相比较,PDS和HAS相结合的PDHAS码书搜索算法可显著降低码书搜索的计算复杂度,从而使语音趑编码时间得到显著降低,且语音编码质量没有显著下降;仿真实验验证本文使用的PDHAS快速码字搜索算法是一种实现矢量量化快速编码的有效方法,对降低码书搜索算法的复杂度、减少语音编码时间具有非常重要的应用价值.  相似文献   

5.
Cotton is a valuable economic crop. The cottonseedafter ginning is made up of fuzz, kernel and hull, amongwhich kernel constitutes about 50% to the seed weight.Cottonseed kernel of G. hirsutum contains about 40% ofprotein and more than 35% of cottonseed oil, which obvi-ously is a potential rich source of high quality protein andedible oil supplement[1,2]. However, the utilization of cot-tonseed is limited by the presence of gossypol and its de-rivatives in seeds of ordinary glanded cotton cult…  相似文献   

6.
文中报道了产于黄土高原的三个新记录种:缩球囊霉在山地及农田土壤中均有出现,频度高,丰度较小。摩西球囊霉仅出现于农田土壤中,频度较高,丰度中等。细凹面无梗囊霉只出现于一个土样中,频度极低,丰度较小  相似文献   

7.
Two G. somalense monosomic alien addition lines were identified from the derived backcross progenies of allohexaploid between G. hirsutum and G. somalense through cytological and morphological observation. Furthermore, the alien addition chromosome was identified and distinguishedby RAPD analysis. A total of 160 RAPD primers were usedfor PCR amplification. Primer SBSG11 could produce a specific molecular marker (600 bp) for monosomic alien addition line Ⅰ (MAAL Ⅰ ). Primer SBSC03 could produce aspecific molecular marker (700 bp) for monosomic alien ad-dition line Ⅱ (MAAL Ⅱ). SBSE07 and SBSE08 could re-spectively produce common molecular marker for mono-somic alien addition lines Ⅰ and Ⅱ. G. somalense alienaddition lines could be important for cotton improvement.  相似文献   

8.
The origins and phylogenetic patterns were assessed for G. przewalskii and G. eckloni by analyzing the complete mtDNA cytochrome b gene sequence (1140bp). Phylogenetic analyses further supported that there were three mtDNA lineages (A-C) identified in G. przewalskii and G. eckloni, demonstrating that outer rakers of the first gill have little significance in the phylogeny of the Gymnocypris fishes. The network established showed that G . eckloni of the Yellow River specific haplotype Al was a founder and it radiated all haplotypes of G. przewalskii which suggested G . przewalskii might only originate from one of two maternals of G . eckloni from the Yellow River. Fs test and mismatch analysis showed at least two expansion events in the population of G. przewalskii about 0.2734 Ma and 0.0658 Ma, while G. eckloni from Qaidam Basin could have experienced severe bottleneck effect about 0.0693 Ma. The population expansion was detected in subclades Al and A21 with the most recent common ancestor (TMRCA) about 0. 2308±0.01 Ma and 0.1319±0. 015 Ma, respectively, which were within the geological age range of "Gonghe Movement" event that caused the separation of Lake Qinghai from the upper Yellow River. These results suggested the effect of the fish diversification by rapid uplift of the Qing-hai-Tibetan Plateau in the Late Pleistocene.  相似文献   

9.
The origins and phylogenetic patterns were assessed for G. przewalskii and G. eckloni by analyzing the complete mtDNA cytochrome b gene sequence (1140bp). Phylogenetic analyses further supported that there were three mtDNA lineages (A-C) identified in G. przewalskii and G. eckloni, demonstrating that outer rakers of the first gill have little significance in the phylogeny of the Gymnocypris fishes. The network established showed that G. eckloni of the Yellow River specific haplotype A1 was a founder and it radiated all haplotypes of G. przewalskii which suggested G. przewalskii might only originate from one of two maternals of G. eckloni from the Yellow River. Fs test and mismatch analysis showed at least two expansion events in the population of G. przewalskii about 0.2734 Ma and 0.0658 Ma, while G. eckloni from Qaidam Basin could have experienced severe bottleneck effect about 0.0693 Ma. The population expansion was detected in subclades A1 and A21 with the most recent common ancestor (TMRCA) about 0.2308±0.01 Ma and 0.1319±0.015 Ma, respectively, which were within the geological age range of “Gonghe Movement” event that caused the separation of Lake Qinghai from the upper Yellow River. These results suggested the effect of the fish diversification by rapid uplift of the Qinghai-Tibetan Plateau in the Late Pleistocene.  相似文献   

10.
AMR与G.729之间的转码算法   总被引:1,自引:1,他引:0  
提出了AMR与G.729语音编码标准之间的2种新型转码算法--索引域转码算法和语音域转码算法.它们分别针对具有相同和不同固定码本结构的语音编码标准进行转码.索引域转码算法直接对2个编码的索引值进行相互转换;语音域转码算法则需要在语音域重新对转换的固定码本及增益进行搜索.实验结果表明,这2种转码算法都能有效地降低转码复杂度,语音域转码算法的算法复杂度仅为传统Tandem转码的55%左右,而索引域转码算法的算法复杂度则不到Tandem转码的10%.同时,索引域转码算法的语音质量相对Tandem转码有所提高,而语音域转码算法则保持了约略相当的语音质量.  相似文献   

11.
桂竹糖芥强心苷G抗心律失常作用   总被引:2,自引:0,他引:2  
iv桂竹糖芥强心苷G可显著降低氯仿引起小鼠室颤发生率,在氯化钙-乙酰胆碱诱发的小鼠房颤模型上表现出较好的抗心律失常作用,对氯化钡和乌头碱所致心律失常有一定的保护作用,但对氯化钙诱发的大鼠心律失常无效。  相似文献   

12.
反相高效液相色谱法测定秦艽和麻花艽中番木鳖酸的含量   总被引:2,自引:0,他引:2  
建立了反相高效液相色谱法测定秦艽、麻花艽中番木鳖酸含量的方法。在检测波长为254nm、柱温30℃、流速1mL·min-1时,用ZORBAXSB-C18柱,以24%的甲醇H2O(含0 04%H3PO4)洗脱,上述成分达到基线分离,该法简便、易行,有较宽的线性范围和良好的线性关系。用该方法测定了秦艽、麻花艽全草及根、茎、叶、花等不同部位番木鳖酸的含量。  相似文献   

13.
G.729A采用共轭结构-代数码激励线性预测编码(CS-ACELP)算法,其速率为8kbit/s,先对码激励线性预测(CELP)编解码器进行一般性描述,随后再对CS-ACELP编解码器分别进行详细的讨论,最后应用Matlab中Simulink软件对G.729A编解码器进行仿真,并用一段语音进行试验,得到满意结果.  相似文献   

14.
郭海涛  徐旭东 《自然科学进展》2003,13(10):1108-1111
无类囊体蓝藻Gloeobacter violaceus的细胞有厚胶质鞘包裹并形成群体,难以进行遗传操作.用注射器反复吸打的方法将胶质鞘剥落,得到大量单个细胞,通过接合转移将外源广宿主质粒pKT210转入G.violaceus.用斑点杂交方法以及对质粒进行酶切图谱分析,均证实外源质粒pKT210确已导入G.violaceus并稳定复制,未发生结构上的变化.从G.violaceus提取的pKT210可转化mcr和mrr基因缺陷的大肠杆菌DH10B却不能转化mcr+mrr+菌株DH5a,表明G.vio-laceus中可能存在甲基化酶系统.  相似文献   

15.
一种快速的代数码书搜索方法   总被引:1,自引:0,他引:1  
代数码激励线性预测(ACELP)编码算法在各类语音编码标准中得到广泛采用.在ACELP码书搜索时.要得到全局最优的码向量,所需运算量很大,难以在硬件系统上实时实现.为降低计算复杂度,提出了一种基于脉冲预选和替换步骤的快速码书搜索方法.该方法采用预选技术来减少可能的脉冲组合,利用两级搜索与判断机制来改善脉冲替换搜索的效率.实验表明,该方法可以有效地降低复杂度,并维持较高的合成语音品质.  相似文献   

16.
G.729标准在个人移动通信、多媒体通信、IP电话、卫星通信及综合业务数字通信(ISDN)等领域具有广泛的应用前景。本文详细分析了G.729算法的C语言源代码,并详细研究了G.729算法在VC 6.0平台上的实现方法和过程,给出了实现结果,并根据实现结果利用MATLAB分析了G.729算法的特点。  相似文献   

17.
本文研究了陆地棉GossypiumhirsutumL.2n=4x=52,品种为泗棉2号)×松散棉(Gossypiumlaxumphilips2n=2x=26)种间杂种三倍体F1(21=3x=39)的形态性状遗传和花粉母细胞减数分裂染色体行为。结果表明,杂种一代有一定的优势,花粉母细胞减数分裂过程中,杂种F1染色体行为不规则,每个细胞染色体平均构型为17.13Ⅰ+10.88Ⅱ+0.04Ⅲ。  相似文献   

18.
棉花是最主要的天然纤维作物,深入进行棉花基因组研究具有重要意义.采用酶解、前后低渗和轻压相结合的方法制备亚洲棉染色体中期膜载片,激光法分离亚洲棉第5号单染色体,建单染色体扩增池后克隆其抗病基因同源序列(RGAs),获得P7、P12、P19和P23等4个序列.序列比对和聚类分析表明,这4条序列均为NBS-LRR类RGAs,P7、P12、P19聚成一类,它们之间的同源性很高,P23聚成另一类,与黑松的RPS2和油菜的RGA30同源性较高.为该染色体分子标记开发、基因克隆乃至全序列测定奠定基础.  相似文献   

19.
绞股蓝与乌蔹莓外形相似,但药理作用却不同。从生长环境、营养器官、解剖结构与化学成分等方面对两者进行了对比,并对两者的药理作用做出了比较。  相似文献   

20.
本文介绍了消炎镇痛膏中主要挥发性成分的气相色谱法。作者在实验中对担体、柱温、内标的选择及料品的预处理等方面进行了初步探讨,对控制本药品的内在质量提出了一个简便易行、结果准确可靠的方法。  相似文献   

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