极高CO_2胁迫对被甲栅藻(Scenedesmus armatus)生理活性和细胞结构影响

以被甲栅藻(Scenedesmusarmatus)为材料研究极高浓度CO2对其生理活性和细胞结构的影响。研究表明,被甲栅藻能在60%的CO2浓度下快速生长,在5%、20%、40%、60%、80%、100%CO2浓度下的平均增长率分别是1.228、0.925、0.741、0.305、0.042、0.001g·L-1·d-1DW。通入极高浓度CO2(20%、40%)后,被甲栅藻细胞的光系统II(PSII)最大光化学效率(Fv/Fm)在24h内明显下降,对PSII抑制作用较明显;其后,随培养时间的增长而逐渐恢复

中国枝角类四新记录亚种(鳃足纲:双甲目)

本文描述了采自四川等省的、我国首次发现的4个枝角类亚种,即美弧网纹溞Ceriodaphnia pulchella pseudohamata Bowkiewcz,1925,西方笔纹溞Graptoleberis testudinaria occidentalis Sars,1901,无常平直溞Pleuroxus laevis incertus Brehm,1934以及宽尾平直潘P.aduncus latic-audatus Brehm,1933。解剖观察描述了盘肠溞科枝角类的头孔,并首次将我国淡水枝角类的分类

南海鳍藻科三个属的分类

鳍藻是一类在热带海洋广为分布的甲藻。其发达且美丽的边翅使藻体形态特异。早在一个世纪前就引起了学者广泛的兴趣。Kofoid,Tai和Skogsberg等人对其形态特征,甲板组成和分类系统等方面进行了研究。本文为海南岛和西沙、中沙群岛邻近海域鳍藻科三个属的分类研究结果,共记载了14个种,其中除二个新种外,异帆藻属Parahistioneis和其余12个种均为我国首次记录。本文采用标本系在1933—1934年、1975—1976年分别采自海南岛以及中、西沙群岛邻近海域的定性标本。

西藏鳃足类动物的生态分布和区系特点

<正> 关于西藏高原鳃足类动物的组成与分布过去只有零星的种类记述。20世纪初叶,Daday(1908)根据Stewart在西藏南部的荡拉(Tang La)和江孜(Gyantze)之间采集的一些标本,写出了首篇报道。此后,Stewart(1911)Bond(1934)、Brehm(1936)以及Brehm和Woltereck(1939)等对“耶鲁北印度考察队”所采集的标本,多次作过报道。

中国胭脂鱼的骨骼形态和胭脂鱼科的分类位置

<正> 中国胭脂鱼Myxocyprinus asiaticus(Bleeker)是迄今知道胭脂鱼科(Catostomidae)分布于我国的一个种,而该科的大多数种属分布于北美洲,总计有14个现存属,大约80个种(Miller,1958)。 方炳文(Fang,1934)对中国胭脂鱼除了发表一个头骨及下咽齿的照片外,主要是阐明这种鱼的体形随不同体长(实际是不同龄期)而改变的事实。Nelson(1948)作了胭脂鱼韦氏器的比较解剖,他提到中国胭脂鱼第二和第三脊椎具有分离的椎体和第一脊椎存在一对横突之外,只简单地

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.

Effects of Bothriocephalus acheilognathi on the polarization response of pronephric leucocytes of carp, Cyprinus carpio

An in vitro assay was used to examine the effect of Bothriocephalus acheilognathi Yamaguti, 1934 (Cestoda: Pseudophyllidea) on the polarization response of pronephric leucocytes of carp, Cyprinus carpio. Leucocytes, isolated from naive, naturally-infected fish and carp injected intraperitoneally with cestode extracts, were exposed to parasite extracts (protein concentrations 0-10.0 mu g ml(-1)), for up to 24 h in the presence or absence of carp serum. In general, polarization responses of the pronephric leucocytes, primarily neutrophils and eosinophils, increased with incubation time although there was no significant difference in the response induced by the different protein concentrations. Differences in the polarization response were, however, observed in naive, naturally infected and injected fish and the cells responded differently in the presence and absence of carp serum. In the absence of carp serum the polarization response of pronephric leucocytes in vitro was significantly reduced with cells obtained from injected and naturally infected fish compared with those obtained from naive carp. This suppression of leucocyte migration was however reduced by the addition of carp serum to the in vitro system. The role of this interaction between the possible suppression of polarization induced by the parasite and stimulation by serum is discussed.

Occurrence of Bothriocephalus acheilognathi in cyprinid fish from three lakes in the flood plain of the Yangtze River, China

Cyprinid fish, Hemiculter leucisculus, Cultrichthys erythropterus and Culter dabryi, were sampled from Liangzi, Honghu and Tangxun lakes in the flood plain of the Yangtze River. The cestode Bothriocephalus acheilognathi Yamaguti, 1934 was found in the 3 lakes, but C. erythropterus sampled from Liangzi lake was found uninfected due probably to the small sample size. Findings of the cestode in the 3 lakes represent the first record of the parasite in the flood plain of the Yangtze River, indicating that B. acheilognathi may be distributed much wider in China than previously recognized.

ON PARADICRANOPHORUS-ACULEATUS (NEISTWESTNOVA-SHADINA, 1935) WITH REMARKS ON ALL OTHER SPECIES OF THE GENUS (ROTIFERA, DICRANOPHORIDAE)

In 1934, the rotifer Paradicranophorus aculeatus was discovered by NEISTWESTNOVA-SHADINA in the River Oka near Murom (Russia). She described it as a Dicranophorus species. In 1958, the rheophilic rotifer was rediscovered in the Polish River Grabia by PAWLOWSKI. This paper reports a third occurence in three samples from the Yun Nan Luoxiao River in China, allowing additional studies of this rare species.

A micromachined SiO2/silicon probe for neural signal recordings

The development of an implantable five channel microelectrode array is presented for neural signal recordings. The detailed fabrication process is outlined with four masked used. The SEM images show that the probe shank is 1.2mm long, 100 mu m wide and 30 mu m thick with the recording sites spaced 200 mu m apart for good signal isolation. The plot of the single recording site impedance versus frequency is shown by test in vitro and the ompedence declines with the increasing frequency. Experiment in vivo using this probe is under way.

基于攻击能力增长的网络安全分析模型

网络脆弱性分析是近年来国内外研究的热点问题之一．基于攻击能力增长的网络安全性分析模型以攻击者的能力增长为主导，参考网络环境配置，模拟黑客攻击自动生成攻击图．使用攻击能力增长表示攻击者的最终目标使得攻击图的表示更为准确．最小攻击代价分析第1次考虑了相似攻击对攻击代价的影响，以便对各条路径的攻击代价进行计算；最小环境改变分析考虑入侵检测的因素对最可能的攻击路径进行分析，对于入侵检测系统的处理更加科学合理；两种分析都为改善网络配置提供了依据．与已有成果相比，模型提出的算法和方法更为实际可行．

一种基于Agent的自适应的分布式入侵检测系统

针对传统分布式入侵检测系统组件之间依赖程度大、系统不够健壮且入侵检测系统自身结构固定不能适应入侵的变化的问题,提出了一种基于Agent的自适应的分布式入侵检测系统(简称AAA-DIDS)·AAADIDS采用Agent概念重新构造系统的组件,改进了分布式入侵检测系统由于高层节点单一无冗余而产生的可靠性差的缺陷,从构造上克服了分布式入侵检测系统的脆弱性·同时,AAADIDS系统采用智能技术构建了自适应的入侵检测系统模型,增加了系统应对入侵行为变化的智能性·AAA-DIDS系统相对于传统的分布式入侵检测系统有效地提高了系统自身的可靠性和针对外界变化的适应能力·

黄土高原子午岭林区6个典型群落优势种的热值和养分特征

能量流动、物质循环和信息传递共同构成了生态系统三大功能。能量是维持生态系统功能与过程的动力,Jordan(1971)认为能量比干物质更能反映出群落对自然资源(特别是太阳能)的利用情况。Long(1934)率先用热值来表示植物所含能量的多少,此后关于植物热值的研究工作逐渐展开。我国的植物热值研究始于20世纪80年代(杨福囤等,1983;祖元刚等,1986),主要集中在海南(林益明等,2000)、福建(林益明等,2004)、广东(任海等,1999)和浙江(郝朝运等,2006)等热带亚热带植物群落以及内蒙古羊草草原(鲍雅静等,2003),但有关黄土高原地区的植被热值研究尚未见报道。子午岭林区是黄土高原主要的天然次生林区,其植被主要是在弃耕地基础上逐渐恢复起来的(邹厚远等,2002)。由于自然因素与人为因素的影响,子午岭的植被在恢复时间上存在较大差异,形成了处于不同演替阶段的各种植被群落类型。本研究选取的6个代表性植被群落分别是沙棘(Hippophae rhamnoides)群落、山杨(Populus davidiana)群落、白桦(Betula platyphylla)群落、油松(Pinus tabulaeform...

半绝缘InP的铁掺杂激活与电学补偿

比较了掺Fe和非掺退火半绝缘(SI)InP材料中Fe杂质的分布,掺杂激活机理以及Fe原子与点缺陷的相互作用.原生掺Fe SI-InP中Fe的替位激活主要通过填隙-跳跃机制,但Fe原子易在位错周围聚集,与空位形成复合体缺陷,占据填隙位等,从而降低Fe的激活效率.在FeP2气氛下退火非掺InP获得的SI-InP材料中,Fe原子的激活主要通过扩散过程的"踢出-替位"机制.退火前材料中存在的In空位使Fe原子通过扩散充分占据In位,同时抑制了材料中深能级缺陷的形成.因此,这种SI-InP材料的Fe激活效率高、电学性能好.