四足型灵长类踝关节的生物力学研究

对狲猴属5个种踝关节和跟骨生物力学和多变量分析的结果表明,踝关节的运动主要与距骨关节面的形态结构有关。楔形指数和骨指数是区别种间差 异的重要指标。结合生态学观察的结果推测,短尾猴和藏酋猴的运动方式最为接近、表现出适应地栖四足型运动的特征,而豚尾猴和熊猴有相对的树栖运 动方式。猕猴的运动介于两者之间,既有一定的地栖性运动,也有较大的树栖性运动 。图3表3参26

Polarisation diversity of conformal arrays based on geometric algebra via convex optimisation

A simple and general design procedure is presented for the polarisation diversity of arbitrary conformal arrays; this procedure is based on the mathematical framework of geometric algebra and can be solved optimally using convex optimisation. Aside from being simpler and more direct than other derivations in the literature, this derivation is also entirely general in that it expresses the transformations in terms of rotors in geometric algebra which can easily be formulated for any arbitrary conformal array geometry. Convex optimisation has a number of advantages; solvers are widespread and freely available, the process generally requires a small number of iterations and a wide variety of constraints can be readily incorporated. The study outlines a two-step approach for addressing polarisation diversity in arbitrary conformal arrays: first, the authors obtain the array polarisation patterns using geometric algebra and secondly use a convex optimisation approach to find the optimal weights for the polarisation diversity problem. The versatility of this approach is illustrated via simulations of a 7×10 cylindrical conformal array. © 2012 The Institution of Engineering and Technology.

松花江浮游生物群落DNA指纹与物种组成比较研究

对2006年1月采自松花江红旗渡口到同江7个样点的浮游生物群落进行了RAPD指纹分析,进而探讨了河流生态系统浮游生物群落DNA指纹与物种组成之间的关系.筛选出的8条随机引物扩增的谱带全为多态性带,其中特有条带所占比例最大(30.2%);形态分类共检测到浮游生物66种,且没有检测到7个样点的共有种类;这些结果显示研究区域浮游生物群落相似性比较低,环境差异性较大.基于DNA指纹的聚类进一步表明,同江、红旗渡口和佳木斯的浮游生物群落较为相似而聚为一枝,哨口、肇源和哈尔滨为一枝,而松原成为单独的一枝.物种组成则将

犁头鳅早期发育

国务院三峡工程建设委员会办公室生态环境项目(SX2006-013); 长江上游珍稀、特有鱼类及保护区措施补偿科研项目(0605042-07); 国家自然科学基金项目(50679095)资助

Classical plume theory: 1937-2010 and beyond

Developing a theoretical description of turbulent plumes, the likes of which may be seen rising above industrial chimneys, is a daunting thought. Plumes are ubiquitous on a wide range of scales in both the natural and the man-made environments. Examples that immediately come to mind are the vapour plumes above industrial smoke stacks or the ash plumes forming particle-laden clouds above an erupting volcano. However, plumes also occur where they are less visually apparent, such as the rising stream of warmair above a domestic radiator, of oil from a subsea blowout or, at a larger scale, of air above the so-called urban heat island. In many instances, not only the plume itself is of interest but also its influence on the environment as a whole through the process of entrainment. Zeldovich (1937, The asymptotic laws of freely-ascending convective flows. Zh. Eksp. Teor. Fiz., 7, 1463-1465 (in Russian)), Batchelor (1954, Heat convection and buoyancy effects in fluids. Q. J. R. Meteor. Soc., 80, 339-358) and Morton et al. (1956, Turbulent gravitational convection from maintained and instantaneous sources. Proc. R. Soc. Lond. A, 234, 1-23) laid the foundations for classical plume theory, a theoretical description that is elegant in its simplicity and yet encapsulates the complex turbulent engulfment of ambient fluid into the plume. Testament to the insight and approach developed in these early models of plumes is that the essential theory remains unchanged and is widely applied today. We describe the foundations of plume theory and link the theoretical developments with the measurements made in experiments necessary to close these models before discussing some recent developments in plume theory, including an approach which generalizes results obtained separately for the Boussinesq and the non-Boussinesq plume cases. The theory presented - despite its simplicity - has been very successful at describing and explaining the behaviour of plumes across the wide range of scales they are observed. We present solutions to the coupled set of ordinary differential equations (the plume conservation equations) that Morton et al. (1956) derived from the Navier-Stokes equations which govern fluid motion. In order to describe and contrast the bulk behaviour of rising plumes from general area sources, we present closed-form solutions to the plume conservation equations that were achieved by solving for the variation with height of Morton's non-dimensional flux parameter Γ - this single flux parameter gives a unique representation of the behaviour of steady plumes and enables a characterization of the different types of plume. We discuss advantages of solutions in this form before describing extensions to plume theory and suggesting directions for new research. © 2010 The Author. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

富营养底质对沉水植物的胁迫研究 Ι.乙酸对伊乐藻和菹草萌发与幼芽生长的影响

湖泊底质中有机物的厌氧代谢产生多种有机酸,其中主要成分是乙酸。研究了暴露于不同浓度的乙酸溶液后伊乐藻(Elodea nuttallii)和菹草(Potam ogeton crispus)无性繁殖体的萌发和幼芽的生长状况。1 mmol/L的乙酸能显著抑制伊乐藻幼芽的生长(p<0.05),但对其繁殖体的萌发无明显影响。在4 mmol/L的乙酸影响下,菹草幼芽仍有明显的生长;菹草繁殖体的萌发受到显著抑制(p<0.05),但在随后的培养中可全部萌发。4 mmol/L以上的乙酸暴露3 d或6 d导致伊乐藻全部死亡,

日本三陆沿岸白胸拟鼠海豚体内铁的蓄积(英文)

根据22头日本三陆沿岸白胸拟鼠海豚的检测结果,研究了必需元素铁在13种组织和器官中的蓄积特征。肺、肝脏和脾脏中铁的浓度显著高于其它脏器,铁在皮肤和鲸脂中的浓度却非常低。研究发现,鲸类肝脏中铁的平均浓度与其最大潜水持续时间有着极其显著的正相关(y=285.17x0.5267;r2=0.92;y:a肝脏中铁的平均浓度,单位为μg·g-1干重;x:最大潜水持续时间,单位为min)。利用该关系式,首次推测白胸拟鼠海豚的最大潜水持续时间为11.85min。

东湖围隔中菹草与藻类生化他感作用的初步研究

中国科学院知识创新工程重要方向项目 (KSCX2 SW 1 0 2 0 7); 国家杰出青年科学基金 ( 3992 5 0 0 7); 武汉市晨光计划 ( 2 0 0 2 5 0 0 1 0 35 ); 湖北省重点项目; 欧洲联盟重大国际科技合作项目资助

异养鞭毛虫原位生长研究进展

近年来 ,异养鞭毛虫随水体生态内浮游动物小型化进程的加剧 ,所占比重越来越大 ,已成为当前生态学研究的重要对象。其研究方法学方面也伴随着发生了革命性变化。通过简单介绍异养鞭毛虫的原位研究方法 ,并就近年来研究成果进行了系统综述

葛仙米光合活性对盐胁迫的反应

收集人工条件下培养的葛仙米球形群体，以不同浓度的NaCl溶液处理，当浓度超过0．2mol／L后，叶绿素a荧光的可变部分（Fv）与最大荧光（Fm）之比值（Fv／Fm）与NaCl浓度呈负相关，光合放氧速率也随着NaCl浓度升高而降低．这两者随氯化钠浓度升高而降低的趋势均呈现出两个阶段性：低NaCl浓度时的缓慢降低阶段和高NaCl浓度时的快速降低阶段．Fv／Fm比值的转折点在0．2mol／L，而光合放氧速率的在0．4mol／L，后者与海水的浓度接近．呼吸作用几乎不受NaCl的影响．光系统I（PSI）和光系统II