饵料鱼大小对乌鳢捕食的影响

测量了乌鳢口裂形态,以泥鳅(Misgurnus anguillicaudatus)作为饵料鱼,估算了不同规格乌鳢的摄食率,研究了饵料鱼大小对乌鳢捕食的影响。乌鳢口宽(MW,cm)、口高(MH,cm)和口面积(MA,cm2)与其全长(TL,cm)的回归方程分别为:MW=1.65e0.0242TL;MH=1.64e0.022TL;MA=2.12e0.0462TL。当水温保持在22~23℃时,4个规格组的乌鳢对泥鳅的摄食率无显著的差别(ANOVA,P>0.05),均值为1.68%。乌鳢对泥鳅的捕食具有明显的大小

复合垂直流人工湿地氧化还原特征及不同功能区净化作用研究

研究了复合垂直流人工湿地系统氧化还原电位(Eh)的时空变化规律及不同功能区中污染物的净化效果。结果表明:湿地系统下行流池表层、两池底层、上行流池表层Eh的变化范围分别为402~585、-87~-130、308~432mV,沿水流方向依次形成了好氧A区/缺氧、厌氧区/好氧B区3个功能区。好氧A区是污染物去除的主要区域,BOD5、CODCr、NH4+-N的去除率分别为43.0%、48.4%、54.1%,特别是NH4+-N去除率占总去除率的79%;缺氧、厌氧区主要是进行反硝化反应和有机物的厌氧分解;好氧B区则主

银鲫3个肌球蛋白轻链基因cDNA的克隆与特征分析

国家自然科学基金 ( 30 130 2 4 0 ) ; 中国科学院知识创新工程重要方向项目 (KSCX2 SW 30 3)资助

Facets of prior experience and the effectiveness of inclusive design

Research in inclusive design has shown the importance of prior experience for the usability of interactive products. Prior experience, however, is an ill-defined and inconsistently used construct. A number of different definitions and operationalisations of experience exist, but the differing power of these operationalisations to predict the usability of products for older users has rarely been investigated systematically. This study seeks to fill that gap. It is argued that the construct of experience has at least three components. It is proposed that two of these components, exposure and competence, are directly relevant for the current discussion about prior experience in inclusive design and that they can predict to different degrees the usability of a product for older users. In an empirical study, these facets of expertise are each operationalised on three levels of specificity and their impact on usability is assessed. The results show that measures of competence predict usability variables more strongly than measures of exposure and that levels of medium and high specificity are the best predictors. The application of inclusive design principles to a redesigned version of a ticket vending machine-although not resulting in a difference of overall usability-changed the impact of prior experience on usability measures implying an enhanced inclusiveness of the redesign with regard to prior experience. The implications of these findings for the effectiveness of inclusive design for older users are discussed. © 2013 Springer-Verlag Berlin Heidelberg.

长喙毛茛泽泻的花器官发生

用扫描电镜对长喙毛茛泽泻（ＲａｎａｌｉｓｍａｒｏｓｔｒａｔｕｍＳｔａｐｆ．）的花器官发生进行了观察。该种的花器官发生在泽泻科中既典型又比较特殊。其特殊之处在于从花原基的发生直至最外轮６枚雄蕊原基的发生过程都存在单向发育：３个萼片原基和３个花瓣原基的发生存在次序性，萼片原基和花瓣原基均为顺时针发生，邻近花序侧生分支复合芽的萼片原基和花瓣原基倾向于优先发生；最外轮６枚雄蕊的发生是成对的按对萼的形式发生。这是以往对该属花器官发生研究没有注意到的。由雄蕊原基向心皮原基的转变发生在与最外轮６枚雄蕊相交替的６个位点，

中国绿球藻目的新记录属、种、变种和变型（下）

中国绿球藻目的新记录属、种、变种和变型（下）胡征宇，凌元洁，梁良弼，毕列爵（中国科学院水生生物研究所武汉４３００７２）（山西大学太原０３０００６）（福建师范大学福州３５０００７）（湖北大学武汉４３００６２）关键词中国，绿球藻目２５．日内瓦顶棘藻（图２...

二龄草鱼肠炎病发病机理

本文通过对患肠炎病的二龄草鱼病鱼和正常草鱼的肠道及血液中的产气单胞菌(Aeromonas)的数量和毒力的比较,病鱼肠道、血液和其他内脏中的产气单胞菌所出现比率的调查,不同水温对该菌致病力的影响和用菌体提取液接种鱼体,以及用鲎试剂(鲎变形细胞溶解物Tachypleus Amebocyte Lysatc “TAL”)对病鱼和正常鱼体内的内毒素进行测定等一系列的试验和观察,从而推断出二龄草鱼细菌性肠炎病的发病机理。

武汉东湖铜锈环棱螺种群变动和生产量的初步观察

本文报道了东湖环棱螺的种群密度、年龄结构、种群增长率和生物量、生产量、P/B系数及其在不同湖区中的季节变化;用指数生长模型计算种群增长率。以累计总增长的方法估算种群生产量。研究结果表明,水果湖区铜锈环棱螺年平均生物量为554.37克·米~(-2),累计生产量为604.99克·米~(-2)·年~(-1),P/B系数为1.09;郭郑湖区平均生物量为286.74克·米~(-2),生产量为308.99克·米~(-2)·年~(-1),P/B系数为1.08。本文还对影响铜锈环棱螺的种群变动和生产量的生态因子作了扼要的

用PFU原生动物群落进行生物监测的研究

应用PFU法收集微型生物群落,监测鸭儿湖的农药污染。原生动物对五个氧化塘内农药废水的毒性反应,可用群集过程来表示,无论室内或是野外试验,结果基本一致。其中微型生物群落的结构参数有原生动物种类组成和种数、叶绿素a含量、水细菌数量;功能参数有反映原生动物群集过程中的S_(eq)、G、t_(90％)和微型生物的呼吸速度。功能和结构的参数均能较准确地反映出氧化塘系统的净化过程。PFU法可应用于预报污染物的生物效应浓度,初认为是一种经济、快速、正确的生物学监测方法。

武昌的秀体溞

<正> 秀体溞(Diaphanosoma)是枝角类栉足族仙达溞科(Sididae)中包括种类最多的一个属,根据已往的记录,共计约有20种。关于我国秀体溞的计载,总共只有7种。最早是由 Spandl 在广东记述了镰角秀体溞(D.excisum Sars)一种。上野益三曾发表过有关我国枝角类的文章多篇,他报告了浙江、四川、台湾、黑龙江、吉林以及内蒙古等地的秀体溞共有6种,即:短尾秀体溞[D.brachyurum(Liévin)],长肢秀体溞

Seasonal occurrence of Dollfustrema vaneyi (Digenea : Bucephalidae) metacercariae in the bullhead catfish Pseudobagrus fulvidraco in a reservoir in China

The seasonal population dynamics of metacercariae of the bucephalid Dollfustrema vaneyi (Tseng, 1930) Echmann, 1934 in the bullhead catfish Pseudobagrus fulvidraco (Richardson) were investigated in Jiangkou reservoir, Jiangxi Province, east China, during the period from April 1990 to August 1991. In total, 523 fish were obtained, and the overall prevalence of the metacercariae was 89.87 % and mean abundance 136.25 +/- 308.09 (mean +/- SD). A pattern of seasonal changes in prevalence and mean abundance was observed, with higher levels of metacercariae infection in late spring and summer. An analysis of the distribution of D. vaneyi in different organs of P. fulvidraco suggested that the eyes might be a suitable location for the parasite. Furthermore, the possible role of metacercariae in bullhead catfish was discussed in relation to the life cycle of this parasite.

Mechanical and chemical bonding properties of ground state BeH2

The crystal structure, mechanical properties and electronic structure of ground state BeH2 are calculated employing the first-principles methods based on the density functional theory. Our calculated structural parameters at equilibrium volume are well consistent with experimental results. Elastic constants, which well obey the mechanical stability criteria, are firstly theoretically acquired. The bulk modulus B, Shear modulus G, Young's modulus E, and Poisson's ratio upsilon are deduced from the elastic constants. The bonding nature in BeH2 is fully interpreted by combining characteristics in band structure, density of states, and charge distribution. The ionicity in the Be-H bond is mainly featured by charge transfer from Be 2s to H 1s atomic orbitals while its covalency is dominated by the hybridization of H 1s and Be 2p states. The Bader analysis of BeH2 and MgH2 are performed to describe the ionic/covalent character quantitatively and we find that about 1.61 (1.6) electrons transfer from each Be (Mg) atom to H atoms.