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1.
淡水浮游植物功能类群分类法的提出、发展及应用   总被引:2,自引:0,他引:2  
浮游植物分类方法是揭示浮游植物群落演替规律、开展淡水生态研究的工作基础和重要工具.林氏分类法和分子鉴定法在生态学应用上存在的不足促进了浮游植物功能类群分类法的发展.功能类群分类法是一种以浮游植物个体生态学为依据的生态分类法.本文概述了浮游植物功能类群(functional group,FG)、生态功能类群(morpho-functional group,MFG)和形态功能类群(morphology-based functional group,MBFG)等浮游植物分类方法的理论基础和分类依据,分析比较了这3种分类方法的优势与不足,认为FG是目前应用于水生生态学研究和水环境生物评价中相对适用的浮游植物分类方法.介绍了功能类群分类法在国内外淡水浮游植物生态学研究中的应用现状,简述了以FG为基础提出的Q指数法和Q-R指数法两种水质评价法的评价标准及存在的不足.
  相似文献   

2.
白质是组成大脑神经网络不可缺少的部分,对白质的探索多采用解剖形态学方法.血氧水平依赖功能性磁共振成像(blood oxygen level dependent functional magnetic resonance imaging,BOLD-fMRI)作为一种研究大脑功能的非侵入性工具已得到了广泛的应用,但是大多数BOLD-fMRI研究集中在大脑灰质,将白质BOLD信号作为噪声处理.事实上,白质的BOLD信号允许我们探索其动态功能特性,构建白质的功能连接网络,进而从功能角度来评估白质的完整性.因此,在已有研究基础上,我们对白质功能研究相对较少的原因以及BOLD信号可能的神经生理基础进行探讨,并概述了近年来已经发表的相关证据.最后,我们梳理了白质BOLD-fMRI研究存在的问题以及未来研究方向.  相似文献   

3.
东灵山地区不同森林群落叶功能性状比较   总被引:31,自引:11,他引:20  
宝乐  刘艳红 《生态学报》2009,29(7):3692-3703
植物功能性状(plant functional trait)是近年来生态学研究的热点.其中叶功能性状(leaf functional trait)与植株生物量和植物对资源的获得、利用及利用效率的关系最为密切.研究了东灵山地区叶功能性状之间的关系、叶功能性状与地形因子的关系,并对不同群落叶功能性状进行了比较.通过Pearson相关分析发现,叶干物质含量(LDMC)与比叶面积(SLA)、叶氮浓度(LNC)、叶磷浓度(LPC)、叶钾浓度(LKC)负相关;叶大小与叶厚度正相关;SLA与 LNC、LPC、LKC正相关;LNC与LPC、LKC正相关;LPC与LKC正相关.通过灰色关联度分析发现,对叶大小、LNC、LKC来讲,海拔是各项地形因子中的首要影响因子;对LDMC、叶厚度来讲,坡度对其影响最大;对SLA、LPC来讲,坡位是其首要影响因子.依据乔木层的SLA和LDMC将5种群落分成3类,第一类是黑桦林和山杨林,第二类是辽东栎林,第三类是胡桃楸林和糠椴林.群落的分类情况符合该地带性植被优势度类型的分类情况,LDMC和SLA是最能体现群落间差异的叶功能性状.  相似文献   

4.
关于单殖吸虫的超微结构研究,国外开展得较多(Lee,1972;Lyons,1973;lumsden,1975;Rohde.1975;Fournier,1981;Smyth and Halton,1983)。国内有关报道很少。本文以我国特有的黑斑蛙双睾吸虫(Diplorchis nigromaculatus)为材料,用扫描电镜观察了其成虫的体表超微结构,试图为探讨这类吸虫的功能形态学(functional morphology)提供一些依据。  相似文献   

5.
静息态功能磁共振(resting-state functional MRI,rs-fMRI)是近年出现的一种新的fMRI技术,它通过研究大脑静息状态的自发活动来反映复杂的人脑活动状态,可为我们探索大脑活动的内部机制提供新的途径。由于它无需复杂的任务实验,近年来被广泛用于神经、精神类疾病的基础与临床研究。本文就近年来国内外对静息态脑功能磁共振在神经、精神类疾病中的研究做一综述。  相似文献   

6.
精神分裂症(schizophrenia)是一种常见的精神疾病,在中国终身患病率大概为6.55‰.研究精神分裂症的语言认知,对精神分裂症的诊断和治疗具有重要的理论和应用价值.本文从行为和神经[事件相关电位(event-related potentials,ERP)、功能磁共振成像(functional magnetic resonance imaging,f MRI)、近红外光学成像(functional near-Infrared spectroscopy,f NIRS)]两个层面简述了国内外精神分裂症语言认知的研究进展.目前西方国家对精神分裂症的语言认知研究较多,结果也很丰富,初步形成了语言损伤的理论,而且发现幻听与语言加工相关脑区(wernicke区)有密切关系.精神分裂症的汉语认知研究起步较晚,各方面还不够深入和完善.作者提出应该大力加强对中国精神分裂症的语言认知研究,不仅可以更加清楚中国精神分裂症患者的语言特点,更重要的是可以为中国精神分裂症患者的诊断和探索发病机制提供新的科学依据.  相似文献   

7.
干热河谷植物叶片,树高和种子功能性状比较   总被引:3,自引:1,他引:2  
植物功能性状 (plant functional trait)是近年来生态学研究的热点。以云南怒江和澜沧江干热河谷36种木本植物为研究对象,选取比叶面积 (SLA)、植株高 (H) 和种子干重 (SM) 3个功能性状,研究它们的相互关系,比较其在河谷间、河谷内的差异。结果表明:1)两个河谷内36种木本植物的以上3种功能性状间没有显著的相关性 (P值分别为0.8739,0.5763,0.5517);2)河谷间的比叶面积存在显著差异 (P=0.02944),植株高和种子干重无显著差异 (P分别为0.4070, 0.8867);3)两个河谷内木本植物功能性状中,种子干重差异最大,植株高次之,比叶面积最小。  相似文献   

8.
家犬(Canis lupus familiaris)与人类社会生态高度融合,已成为人类解析认知进化理论、进行比较认知研究、开展人类认知功能障碍性疾病研究的一种自然模型动物。功能性磁共振成像(functional magnetic resonance imaging, fMRI)是一种非侵入式、安全的能反映生物体大脑神经活动时空分布的神经影像学技术,近年来被应用于家犬行为认知特征神经机制的研究。本文简介了fMRI技术;概述了部分研究者使用视觉、嗅觉、听觉等不同的实验范式对家犬大脑开展fMRI,定位不同实验范式下被激活的大脑功能区,从而揭示家犬认知的神经机制;总结了fMRI技术在犬认知研究中技术和方法上的挑战。以期为国内开展家犬等动物认知研究者提供新的技术方法。  相似文献   

9.
功能磁共振成像(functional magnetic resonance imaging,fMRI)被用于检测静息时脑功能神经网络.作者运用静息fMRI检测海马硬化颞叶癫痫(temporal lobe epilepsy,TLE)脑"默认模式",采用感兴趣区域功能连接分析检测16例TLE患者和16名正常对照静息时脑的"默认模式",并进行组内和组间分析.研究发现,与正常对照相比,TLE静息时海马、颞极、额叶、颞叶、壳核及楔前叶等脑区与后扣带回的功能连接增强.研究结果表明TLE患者的固有脑功能组织模式有可能出现紊乱.这一研究将有助于从脑功能的角度了解癫痫患者某些临床症状的发病机理,为今后癫痫诊治的发展提供一定的帮助.  相似文献   

10.
基因组研究计划包括以全基因组测序为目标的结构基因组学和以基因功能鉴定为目标的功能基因组学两方面的内容。目前基因功能鉴定的方法主要有:基因表达的系统分析(SAGE)、cDNA微阵列、DNA(基因)芯片、蛋白组技术以及基于转座子标签和T_DNA标签的反求遗传学技术等。本文对上述各种技术的优缺点以及它们在植物基因功能鉴定中的应用进行了综述。 Abstract: The genome projects comprise the structural genomics focusing on determining the complete sequences of the genome and the functional genomics focusing on elucidating the biological function of genes.The rapidly evolving tools for functional genomics research include Serial Analysis of Gene Expression (SAGE),cDNA microarray,DNA (or gene) chips,proteome project and the reverse genetics technique based on the well-established transposon tagging and T?DNA tagging systems.In this paper,the advantages and disadvantages of such techniques and application of these techniques in plant functional genomics research are reviewed and future prospective are also presented.  相似文献   

11.
A new functional classification of muscles, determining movements of the mandible is presented. This classification reflects anatomo-topographic and histogenetic peculiarities of the muscles in question. Their functional differentiation in phylogenesis is motivated, coming from specific tasks they perform. Two groups of muscles of direct and mediated action on the mandible are distinguished. The groups are divided into functional subgroups. Mathematical correlations between various subgroups of the muscles at normal functioning of the mandible are presented. This makes possible to perform calculations of the acting muscle forces at planning reconstructive operative interventions in the maxillofacial area.  相似文献   

12.
The use of the dorsalis pedis flap with vascularized extensor tendons was presented. An anatomic study has been carried out that has shown that the vascularization of the foot extensor tendons can be exclusively dependent on the blood contribution coming from the dorsalis pedis artery. In two cases that are presented and followed up for over a year after the surgery, the functional results obtained are good in the hand and aesthetically acceptable in the foot.  相似文献   

13.
To manipulate host defences, plant pathogenic oomycetes secrete and translocate RXLR effectors into plant cells. Recent reports have indicated that RXLR effectors are translocated from the extrahaustorial matrix during the biotrophic phase of infection and that they are able to suppress PAMP-triggered immunity. Oomycete genomes contain potentially hundreds of highly diverse RXLR effector genes, providing the potential for considerable functional redundancy and the consequent ability to readily shed effectors that are recognised by plant surveillance systems without compromising pathogenic fitness. Understanding how these effectors are translocated, their precise roles in virulence, and the extent to which functional redundancy exists in oomycete RXLR effector complements, are major challenges for the coming years.  相似文献   

14.
The authors report the results of their observations on the lowest sigmoid artery, carried out on 92 anatomical specimens coming from surgical operations on the sigmoid and rectum. The specimens were injected and radiographed immediately after their removal . The observations were often preceded by pre-operative angiographies performed for diagnostic reasons. The AA. document all the variational patterns of this artery. They confirm the poor functional value of this artery more known by the old surgeons than by the anatomists.  相似文献   

15.
Recent large-scale studies of protein complexes in yeast have demonstrated that the wide majority of proteins exist in the cell as parts of multicomponent assemblies, mostly novel and of unknown function. The structural and functional analysis of these complexes should be a priority for structural biologists in coming years. In silico methods such as docking simulations, which may contribute to this analysis, are being tested in the CAPRI community-wide experiment, which assesses blind predictions of the structure of protein-protein complexes.  相似文献   

16.
Polystyrene grafted with a chiral zinc‐complexing camphor‐derived N,N‐disubstituted hydroxyamide is proposed as a new type of functional polymer of high reusability for the development of sustainable organozinc‐catalyzed asymmetric reactions. The main goal of this new functional polymer is the ease of the hydroxyamide‐moiety preparation (cheap chiral ligand obtained straightforwardly from an enantiopure starting material coming from the chiral pool), as well as its chemical robustness when compared with other related zinc‐complexing functional groups. The latter allows the polymer to be active after multiple applications, without significant loss of its catalytic activity. This fact is exemplified by the design and preparation of a polymer functionalized with a bis(hydroxyamide) proved previously as active in the homogeneous enantioselective addition of diethylzinc to aldehydes. The result is a cheap functional polymer with a very high reusability (the enantioselectivity and chemical yield are maintained practically constant after 20 applications). Additionally, a methodology for the multicycle use of these functional polymers is presented. Chirality, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

17.
Large-scale RNA interference (RNAi)-based analyses, very much as other 'omic' approaches, have inherent rates of false positives and negatives. The variability in the standards of care applied to validate results from these studies, if left unchecked, could eventually begin to undermine the credibility of RNAi as a powerful functional approach. This Commentary is an invitation to an open discussion started among various users of RNAi to set forth accepted standards that would insure the quality and accuracy of information in the large datasets coming out of genome-scale screens.  相似文献   

18.
Approaches to functional genomics in filamentous fungi   总被引:8,自引:0,他引:8  
The study of gene function in filamentous fungi is a field of research that has made great advances in very recent years. A number of transformation and gene manipulation strategies have been developed and applied to a diverse and rapidly expanding list of economically important filamentous fungi and oomycetes. With the significant number of fungal genomes now sequenced or being sequenced, functional genomics promises to uncover a great deal of new information in coming years. This review discusses recent advances that have been made in examining gene function in filamentous fungi and describes the advantages and limitations of the different approaches.  相似文献   

19.
20.
《Insect Science》2007,14(2):171-171
We are building on the success of the Sixth Chinese Insect Physiology, Biochemistry and Molecular Biology Symposium, Beijing, held in 2005. The 2005 symposium saw many Chinese and international authorities share their expertise in a broad range of insect science, including analyses of insect genomes and proteomes, functional gene expression and regulation during development, insect immunity, insect neurobiology, insect-host interactions and insect chemical communication. The coming symposium, which will be held in Shandong University, Jinan, Shandong province, September 19-22, 2007, will offer material along similar lines.[第一段]  相似文献   

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