Evaluation of marine phytoplankton toxicity by application of marine invertebrate bioassays

The dinoflagellate Alexandrium minutum and the haptophyte Prymnesium parvum are well known for their toxin production and negative effects in marine coastal environments. A. minutum produces toxins which cause paralytic shellfish poisoning in humans and can affect copepods, shellfish and other marine organisms. Toxins of P. parvum are associated with massive fish mortalities resulting in negative impacts on the marine ecosystem and large economic losses in commercial aquaculture. The aim of this work is to improve our knowledge about the reliability of the use of marine invertebrate bioassays to detect microalgae toxicity, by performing: (i) a 24- to 48-h test with the brine shrimp Artemia franciscana; (ii) a 48-hour embryo-larval toxicity test with the sea urchin Paracentrotus lividus; and (iii) a 72-h test with the amphipod Corophium multisetosum. The results indicate that A. franciscana and P. lividus larvae are sensitive to the toxicity of A. minutum and P. parvum. LC50 comparison analysis between the tested organisms reveals that A. franciscana is the most sensitive organism for A. minutum. These findings suggest that the use of different organizational biological level bioassays appears to be a suitable tool for A. minutum and P. parvum toxicity assessment.

Dispersion of gamma-Alumina Nano-Sized Spherical Particles in a Calamitic Liquid Crystal. Study and Optimization of the Confinement Effects

We report an experimental study on confined systems formed by butyloxybenzylidene octylaniline liquid crystal (4O.8) + gamma-alumina nanoparticles. The effects of the confinement in the thermal and dielectric properties of the liquid crystal under different densities of nanoparticles is analyzed by means of high resolution Modulated Differential Scanning Calorimetry (MDSC) and broadband dielectric spectroscopy. First, a drastic depression of the N-I and SmA-N transition temperatures is observed with confinement, the more concentration of nanoparticles the deeper this depression is, driving the nematic range closer to the room temperature. An interesting experimental law is found for both transition temperatures. Second, the change in shape of the heat capacity peaks is quantified by means of the full width half maximum (FWHM). Third, the confinement does not noticeably affect the molecular dynamics. Finally, the combination of nanoparticles and the external applied electric field tends to favor the alignment of the molecules in metallic cells. All these results indicate that the confinement of liquid crystals by means of gamma-alumina nanoparticles could be optimum for liquid crystal-based electrooptic devices.

玉米新老品种生理生态特征与竞争力差异研究

本文以中国不同年代主要的玉米品种为试验材料，深入研究了玉米品种更替过程中新老品种的生理生态特征和竞争力差异，分析了差异形成的原因并进行了理论探讨。 玉米新老品种竞争力差异的研究采用了单作和混作两种方式，设高低两个密度。生长过程中全面测量了生物量、形态、生理和群体指标，运用了生长分析的方法来研究竞争，整合了各水平参数来解释竞争结果，并用本研究数据检验了生长冗余理论。 玉米新老品种对比研究发现新品种的生理生态特征普遍优于老品种。这些优势不仅体现在较高的生物量积累、较大的籽粒库容和较强的再分配能力上，而且体现在高的叶面积指数、衰老过程中仍维持较高的叶绿素含量、可溶性蛋白含量和光合效率上，同时新品种的群体特性还具有更低的感病率和更少的无效分蘖。玉米新老品种竞争结果表明在混作条件下，相对总产量这一指标反映出新老品种间明显的互利效应，且这种效应随发育阶段而降低。新品种对老品种的相对竞争力则随着发育阶段波动，并且密度和发育阶段两因子对品种竞争力的影响有明显的相互作用。相对于新品种，老品种的确存在叶片和根系的生长冗余部分，但老品种并没有在混作竞争中获得明显的竞争优势，即玉米品种选育并不完全符合生长冗余理论，因此在理解植物竞争力方面仍需要其他层面更深入的探讨。 同时，玉米品种选育不完全符合生长冗余理论的结论在农学实践上并非毫无价值。因为新品种总生物量的提高，不仅增加了籽粒产量，而且增加了秸秆产量，提供了更多可利用的生物质资源。相对于仅仅关注粮食产量，综合利用中国农村巨大的生物质资源具有更重要的生态意义。

麻栗坡县家马mtDNA多态性研究

对采自麻栗坡县的晋通马矮马各３匹的材料，所用２０种限制性内切酶中，有１６种可产生切点，平均每个个体获得５６条限制性片段。与其它家畜家一不同，家马有高度的ｍｔＤＮＡ多态性，６匹马均有自己独特的ｍｔＤ－ＮＡ基因型，提示该地家马可能为多起源，至少有多重母系，这些母系可追溯到１～１０万年前，与化石记载相一致。本次实验未找到将两种马区分开的特异性多态标记，这可能是同栖于同一生态环境中，相互交配，血液相融，而不是各自起源于自己原母系。由于所测样本数较少，尚不能得到区分两种马的一个统计学上的规律性来。云南地理地貌十分复杂，马的品种或类群较多，亦可能是多起源，其遗传多样性很丰富。因此，云南马是值得保护和重视的种质资源库。自８０年代以来，动物线粒体ＤＮＡ（ｍｔＤ－ＮＡ）在群体遗传及进化生物学研究中起着重要作用，由于其组成序列简单，母体遗传，且不存在重组，所以是追踪母系血统的理想标记和能对漂移血统进行识别￣［１］（Ｈａｒｒｉｓｏｎｌ９８９年）．在家养动物中，对ｍｔＤＮＡ多态性研究以前多在鸡、黄牛、猪中进行，它们的ｍｔＤＮＡ多态频率相当低￣［２］。Ｍａｒｔｈｅｗ和Ｒｙｄｅｒ（１９８６）的研究已涉及家马ｍｔＤＮＡ种内特异性的情况.

A comparison of two models for the vibration response of piled foundations to inertial and underground-railway-induced loadings

The vibration response of piled foundations due to ground-borne vibration produced by an underground railway is a largely-neglected area in the field of structural dynamics. However, this continues to be an important aspect of research as it is expected that the presence of piled foundations can have a significant influence on the propagation and transmission of the wavefield produced by the underground railway. This paper presents a comparison of two methods that can be employed in calculating the vibration response of a piled foundation: an efficient semi-analytical model, and a Boundary Element model. The semi-analytical model uses a column or an Euler beam to model the pile, and the soil is modelled as a linear, elastic continuum that has the geometry of a thick-walled cylinder with an infinite outer radius and an inner radius equal to the radius of the pile. The boundary element model uses a constant-element BEM formulation for the halfspace, and a rectangular discretisation of the circular pile-soil interface. The piles are modelled as Timoshenko beams. Pile-soil-pile interactions are inherently accounted for in the BEM equations, whereas in the semi-analytical model these are quantified using the superposition of interaction factors. Both models use the method of joining subsystems to incorporate the incident wavefield generated by the underground railway into the pile model. Results are computed for a single pile subject to an inertial loading, pile-soil-pile interactions, and a pile group subjected to excitation from an underground railway. The two models are compared in terms of accuracy, computation time, versatility and applicability, and guidelines for future vibration prediction models involving piled foundations are proposed.

phbB基因在莱茵衣藻中的表达与分子检测

通过构建依赖NADPH的乙酰乙酰CoA还原酶基因(phbB)的衣藻表达载体, 用石英砂VOTEX转化技术, 将phbB基因导入细胞壁缺陷的莱茵衣藻(Chlamydomonas reinhardtii cc-849)中, 用含有10 mg/mL的Zeomycin的平板培养基进行筛选和实验室保持培养, 得到了表达phbB基因的转基因藻株. PCR和Southern blot结果显示phbB基因已整合到莱茵衣藻基因组中. RT-PCR与DNA杂交的检测结果显示, 导入的phbB基因在衣藻中具有转录活性.

KHAWIA SAUROGOBII N. SP (CESTODA: CARYOPHYLLIDEA) FROM FRESHWATER FISH SAUROGOBIO SPP. (CYPRINIDAE) IN CHINA

Khawia saurogobii n. sp. is described from the intestine of the cyprinid fishes Saurogobio dabryi and Saurogobio dumerili in China. The new species belongs to the Lytocestidae and is placed in Khawia because of its afossate scolex, vitelline follicles in the cortical parenchyma, uterus not looping anterior to the cirrus sac, gonopores separate but close together in distinct genital atrium, external seminal vesicle absent, and postovarian follicles present. The new species differs from other congeneric species by the shape of the body markedly tapering posteriorly from the end of the anterior third, the shape of the scolex that is very short and markedly wider than the neck, spatulate without incisions, but shallow superficial grooves, vitelline follicles and testes starting immediately posterior to the scolex, and an ovary with long, posterior arms bent medially, thus giving the shape of an inverted A.

Hypersausage neural networks and its application in face recognition

In this paper, we firstly give the nature of 'hypersausages', study its structure and training of the network, then discuss the nature of it by way of experimenting with ORL face database, and finally, verify its unsurpassable advantages compared with other means.

黄埔发电厂5号机组保温状况的测试与评价

黄埔发电厂5号机组保温状况的测试与评价中科院广州能源研究所刘民义，仝兆丰黄埔发电厂陈丰保温是火力发电厂节能工作的重要方面，保温良好不仅可以减少散热损失，而且也可以提高机组运行的可靠性及快速启动能力［1］，改善环境并保证运行检修人员的人身安全。中科院广...