Identification of factors affecting the growth and survival of the settling Japanese flounder larvae, Paralichthys olivaceus

A series of experiments were conducted to identify the factors that affected the growth and survival of the settling flounder larvae Paralichthys olivaceus. Settling larvae 24 days after hatching (DAH) were reared in 10-l experimental tanks up to 40 DAH, and two of the following factors were changed as controlled factors in each experiment: light regime (24L:0D or 12L:12D), prey density (1500, 3000, or 5000 Artemia l(-1)), shelter (sand or no sand) and stocking density (5, 10, or 15 fish l(-1)). Early settling larvae (24-35 DAH) experienced little mortality (less than 10% of the overall mortality) that was not significantly affected by above factors. In contrast, late settling larvae (36-40 DAH) suffered high cannibalistic mortality which was significantly influenced by each of the above factors. Larvae experienced significantly lower mortality at 10 fish l(-1) level than at other densities. Larvae at 15 fish l(-1) level had higher mortality than at 5 fish l(-1) when all other factors were identical. Larvae at 3000 and 5000 Artemia l(-1) treatments survived significantly better than at 1500 Artemia l(-1), but no significant differences in larval mortality were found between the two higher densities. Larvae suffered higher mortality at low prey density or at the absence of sand when they were exposed to longer photoperiod. Low stocking density significantly improved the growth of the settling larvae. The average daily instantaneous growth rate (G) at 5 and 15 fish l(-1) treatments were 0.050 and 0.034, with the coefficient of variation (CV) in final length at 16.4 and 23.5, respectively. Daily instantaneous growth rate increased significantly from 0.033 in the 1500 Artemia l(-1) to 0.041 and 0.045 in the 3000 and 5000 Artennia l(-1), respectively, but no significant difference in larval growth existed between the two higher prey densities. These findings suggested that the optimal prey density for growth and survival of the settling flounder larvae at a stocking density of 5 - 15 fish l(-1) was around 3000 Artemia l(-1) . Larvae that were exposed to 24L showed 20% increase in growth ( G = 0.046, CV = 18.7) than those exposed to 12L ( G = 0.037, CV = 20.5). Longer exposure to light significantly improved larval growth, provided sufficient food was available. Sand substrate did not show significant effects on larval growth, possibly because the larvae spent most of the time swimming or feeding in the water column during this stage. (C) 2003 Elsevier Science B.V. All rights reserved.

南门峡裂腹鱼亚科鱼类形态相似种的分类学地位——形态趋同进化实例

受高原抬升所致的水系变迁及人类活动的影响,分布于南门峡河流的裂腹鱼亚科鱼类与黄河干支流种群间的基因交流受到长期限制.作为孤立小群体,探讨其分类学地位及其在小生境中的进化机制对了解青藏高原鱼类多样性和物种的形成、进化具有重要意义.本文采用聚合酶链式反应(PCR)和直接测序方法获得了南门峡裂腹鱼亚科鱼类(n=29)及其近缘种(n=19)共48个个体的线粒体DNA(mtDNA)细胞色素b(cyt b)基因的全序列(1 140 bp),并以厚唇裸重鱼和尖裸鲤为外群构建了MP和Bayesian系统进化树.南门峡裂腹鱼亚科鱼类29个个体的序列经排序后,发现有100个(8.77%)多态性位点,共定义了16个单倍型,在系统进化树上分布于截然不同的两个族群中.其中5个单倍型(NMX3、6、7、13、15)与其近缘种花斑裸鲤和青海湖裸鲤形成单系群(MP 99%,Bayesian 98%),而其余11个单倍型(NMX1、2、4、5、8、9、10、11、12、14、16)与黄河干支流的黄河裸裂尻鱼形成另一个单系群(MP 99%,Bayesian 99%).序列差异分析显示,分布于不同族群的南门峡裂腹鱼亚科鱼类之间存在较大的碱基差异(平均为7.42%),显示出种间差异水平,表明分布于南门峡河流的裂腹鱼亚科鱼类可能是花斑裸鲤和黄河裸裂尻鱼形态相似种的复合体.结合青藏高原隆升所致的气候环境变化和高原北部水系变迁的事件,推断形态趋同进化可能导致了南门峡河流裂腹鱼亚科鱼类形态相似种的共存,而小生境自然选择压力是引发适应性形态趋同进化的主要原因.

青海种子植物特有种及其生态地理分布

主要依据中国科学院西北高原生物研究所青藏高原生物标本馆内所存标本为基础,结合对相关资料的全面收集,整理出青海特有植物82种和37变种,隶属19科54属.文中除了分科、属列出每个种或种下类型在青海境内到县一级的产地、生境和海拔高度等以外,还列出了它们的原始文献和可供引证、查阅的标本号.是研究青海高原植物区系的组成、性质和特点以及发生和演变规律等方面问题的基础资料.

高寒草甸退化对鹅绒委陵菜克隆生长特征的影响

为了揭示高寒草甸典型匍匐茎克隆植物对不同生境的生态适应对策，验证生境适应假说，并为高寒草地的退化演替机理研究提供依据，以调查统计和比较样地法研究了江河源区高寒草甸退化对鹅绒委陵菜克隆生长特征的影响。研究表明，重度退化草甸的植物群落结构、功能以及土壤特征发生了明显的变化，继而对鹅绒委陵菜无性系的克隆生长行为和形态特性产生了影响。高寒草甸退化后鹅绒委陵菜的匍匐茎增多，分支强度加大。退化草甸内鹅绒委陵菜的基株高度小于未退化草甸，根长大于未退化草甸，基株的叶片数目问没有明显差别。退化草甸的分株高度显著小于未退化草甸，而分株叶数大于未退化草甸，根长小于未退化革甸且差异不显著。未退化草甸内鹅绒委陵菜无性系的问隔子长度、粗度和匍匐茎长度大于退化草甸，间隔子平均数目少于退化草甸，差异都不显著。随着鹅绒委陵菜无性系匍匐茎数目的增加，不论重度退化草甸与未退化草甸，用于鹅绒委陵菜克隆繁殖的能量投资也逐渐增加。鹅绒委陵菜在未退化草甸用于克隆繁殖的能量投资比例高于退化草甸，其中未退化草甸内鹅绒委陵菜基株的干重占无性系总生物量的比例略低于退化草甸，分株和匍匐茎的干重占无性系总生物量的比例高于退化草甸。高寒草甸退化对鹅绒委陵菜克隆生长特征的这些影响，与植物群落结构和功能的变化导致生境变异密切相关，是其对高寒草甸退化导致的资源和生境差异的反应，也是对资源利用达到的最合理状态，是一种选择适应的结果，有利于克隆繁殖潜力的发挥。同时为生境适应假说提供了又一例证。

江河源区人工草地群落特征、多样性及其稳定性分析

对江河源区人工草地群落特征、多样性及其稳定性的研究结果表明,不同处理草地植物群落的物种丰富度、多样性、均匀度指数因时间和空间的变化而有明显的差异,群落演替从5龄到6龄,各群落丰富度和多样性指数增加,生物生产量降低,群落相似性系数增大.5龄老芒麦+早熟禾混播人工草地(LP5)群落的地上生物量最高(379.6 g/m2),老芒麦单播(ES5)居中(323.4 g/m2),对照组(CKF5和CK5)最低(124.3和118.6 g/m2).6龄植物群落地上生物量依次为原生植被+封育(VP6,310.1 g/m2)>老芒麦+早熟禾混播(LP6,216.3 g/m2)>老芒麦单播(ES6,190.8 g/m2)>对照(CK6,88.7 g/m2).群落间相似性系数的变化说明,单播(ES)与混播(LP)人工草地群落有趋同演化的趋势.人工草地群落随着结构的复杂化,与对照群落间的相似性提高,说明群落处于退化演替阶段,物种丰富度和多样性增大,群落稳定性提高.

Stability of alpine meadow ecosystem on the Qinghai-Tibetan Plateau

The meadow ecosystem on the Qinghai-Tibetan Plateau is considered to be sensitive to climate change. An understanding of the alpine meadow ecosystem is therefore important for predicting the response of ecosystems to climate change. In this study, we use the coefficients of variation (Cv) and stability (E) obtained from the Haibei Alpine Meadow Ecosystem Research Station to characterize the ecosystem stability. The results suggest that the net primary production of the alpine meadow ecosystem was more stable (Cv = 13.18%) than annual precipitation (Cv = 16.55%) and annual mean air temperature (Cv= 28.82%). The net primary production was insensitive to either the precipitation (E = 0.0782) or air temperature (E = 0.1113). In summary, the alpine meadow ecosystem on the Qinghai-Tibetan Plateau is much stable. Comparison of alpine meadow ecosystem stability with other five natural grassland ecosystems in Israel and southern African indicates that the alpine meadow ecosystem on the Qinghai-Tibetan Plateau is the most stable ecosystem. The alpine meadow ecosystem with relatively simple structure has high stability, which indicates that community stability is not only correlated with biodiversity and community complicity but also with environmental stability. An average oscillation cycles of 3-4 years existed in annual precipitation, annual mean air temperature, net primary production and the population size of consumers at the Haibei natural ecosystem. The high stability of the alpine meadow ecosystem may be resulting also from the adaptation of the ecosystem to the alpine environment.

An application of the analytic hierarchy process and fuzzy logic inference in a decision support system for forage selection

Forage selection plays a prominent role in the process of returning cultivated lands back into grasslands. The conventional method of selecting forage species can only provide attempts for problem-solving without considering the relationships among the decision factors globally. Therefore, this study is dedicated to developing a decision support system to help farmers correctly select suitable forage species for the target sites. After collecting data through a field study, we developed this decision support system. It consists of three steps: (1) the analytic hierarchy process (AHP), (2) weights determination, and (3) decision making. In the first step, six factors influencing forage growth were selected by reviewing the related references and by interviewing experts. Then a fuzzy matrix was devised to determine the weight of each factor in the second step. Finally, a gradual alternative decision support system was created to help farmers choose suitable forage species for their lands in the third step. The results showed that the AHP and fuzzy logic are useful for forage selection decision making, and the proposed system can provide accurate results in a certain area (Gansu Province) of China.

纳米级微动平台的设计与实验研究

纳米级微动平台（以下简称微动平台）是微机电系统的重要组成部分，其技术涵盖多个领域的先进技术，其应用范围和领域也越来越广泛。微动平台是实现纳米尺度观测与操作的关键部件。纳米级微动平台的机械性能如力学和运动学特性，直接影响纳米作业系统的应用效果。本文以纳米级微动平台的设计开发为目标，采用CAD和CAE技术，以机械设计理论、有限元方法、显微视觉检测技术等为研究手段，较深入地研究了一种基于PZT驱动的非耦合2维纳米级微动平台的结构设计、结构力学特性以及运动精度等关键技术问题。为此类纳米级微动平台的设计、加工、组装与测试提供了基本理论依据和实现途径。主要工作如下： 1 针对非耦合纳米级微动平台的应用背景和技术要求，应用CAD和CAE技术完成了基于弹性筋板导向和压电陶瓷驱动的新型纳米级微动平台的结构设计。 2 研究采用有限元分析软件ANSYS和COSMOSWorks对所设计的纳米级微动平台进行了结构力学仿真分析，理论上证明了平台结构设计的合理性及可行性。 3 针对驱动器装配误差、导向筋板的加工误差对平台运动精度的影响问题，研究采用有限元仿真方法对平台的运动精度进行了定量的计算分析。 4 研究采用显微视觉技术和序列图像处理技术，完成了纳米级微动平台动态运动性能的检测，给出了平台的动态输入输出特性以及运动过程中平台边框的变形情况。

石英裂变径迹蚀刻条件的对比实验研究

通过40％的HF溶液、KOH饱和溶液和19mol／L的NaOH溶液这三种常用方法对大、小颗粒石英进行裂变径迹蚀刻实验的对比发现，用环氧树脂固定的小颗粒石英样品，不宜用KOH饱和溶液（150℃）和19mol／L的NaOH溶液（沸点，约120℃）作为裂变径迹的蚀刻剂，宜用40％的HF溶液；三种方法均适宜于大颗粒石英，但不同的蚀刻方法蚀刻效率不同，40％的HF溶液（29℃）的蚀刻效率最高，且操作简单、安全性高。40％的HF溶液最佳蚀刻时间为：温度在4℃左右（冬季）时为40min，温度在29℃左右（夏季）时为30min，可在全年室内常温条件下操作。

贵州喀斯特山区植物营养元素含量特征

贵州喀斯特山区是我国乃至世界喀斯特分布面积最大的片区之一，由于其生态系统的脆弱性，加之人类活动的干扰，使得该区的植被退化较为严重。文章选择该区的12 种主要植物作为研究对象，对其营养元素进行了研究。结果表明：>1 000μg·g-1 的元素有N、P、K、Ca、Mg、S，100~1 000 μg·g-1 的元素有Fe、Mn、Al，10~100 μg·g-1 的元素有Zn、Sr，<10 μg·g-1的元素为Cu、Mo，其中Mo 含量最低，仅为0.17 μg·g-1。这些元素中，Ca、P、K 元素高于所报道的陆生植物的含量范围。元素含量特点是Ca>K>Mg 型。N、P、K、Mg 元素的频数分布为正态分布，Ca、Al、Fe、Mn、Cu、Zn、Sr、S 元素为对数正态分布。变异系数大于100%的元素有Al、Fe、Mn、Sr，变异系数小于60%的元素有N、P、K、Ca、Mg、S、Cu，其中Ca 的变异系数最小，仅为11.8%。不同生境下相同植物的营养元素含量有较大的差异，石灰土上植物的N、P、K、Ca、Mg、Al、Cu、Mo 元素含量要高于黄壤上植物的。元素间的相关分析表明：P 和K、P 和Cu、Al 和Fe、Al 和Zn、Fe 和Zn 元素具有显著相关关系；N 和P、P 和Mg、K 和Al、K 和Cu、Ca 和Sr、S 和Mo 元素具有一般相关关系。

织金新华磷矿碎屑磷灰石的矿物成分研究

织金新华磷矿是我国扬子地台西南缘早寒武世重要的海相沉积磷矿床。长期以来，织金磷块岩磷酸盐矿物成分被认为是碳氟磷灰石或低碳氟磷灰石，有学者认为，产于沉积岩中的磷灰石基本上都属于碳氟磷灰石。本文利用电子探针的微区成分定量分析技术和X射线衍射分析技术，确认织金磷矿碎屑磷灰石为氟磷灰石。

陶瓷釉的矿物学特征研究

应用原子吸收光谱（ＡＡＳ），Ｘ射线衍射（ＸＲＤ）和电子自旋共振（ＥＳＲ）方法对工业及民用陶瓷釉进行了研究。实验表明：陶瓷釉的主要化学成分为Ａｌ２Ｏ３、ＳｉＯ２，少量为Ｋ２Ｏ、Ｎａ２Ｏ、ＭｇＯ、ＣａＯ和微量的ＴｉＯ２、Ｆｅ２Ｏ３、Ｓ等；矿物相有石英、伊利石、方解石、长石、高岭石和滑石等。生釉经不同温度焙烧后，无论是化学成分、矿物相、微量杂南元素的价态及含量均发生的变化。讨论了在不同温度下的化学组分.

滇东南白牛厂银多金属矿床成矿元素特征

成矿物质来源是研究矿床成因的关键问题之一,而地质体（地层和岩浆岩）成矿元素的含量高低是探讨成矿物质来源的基础.为了研究白牛厂超大型银多金属矿床主要成矿元素特征,本文系统测定了外围赋矿地层以及矿区花岗岩和花岗斑岩的成矿元素（Ag、Pb、Zn、Sn）含量,结果表明,Pb、Zn主要来源于矿区花岗岩,寒武系及下伏基底地层可能也提供了部分成矿物质,特别是Zn;由于矿区外围赋矿地层的Sn含量远低于Pb、Zn的含量,也远远低于地壳克拉克值,因此推测,Sn主要来源于花岗岩浆;Ag则主要来源于赋矿地层,花岗岩对其进行了后期的改造作用.

镁铁岩-超镁铁岩侵入体含铂性评价标志

镁铁岩-超镁铁岩侵人体中常常含有少量及微量硫化物，它们是硅酸盐岩浆与硫化物熔体不混溶作用的产物。由于岩石圈环境下铂族元素亲硫性的制约，当硅酸盐岩浆与硫化物熔体呈液态熔离时，铂族元素便被硫化物熔体所捕集和运载，尔后在重力分异过程中下沉到岩盆底部富集成矿。能否依据岩盆上部岩浆熔离硫化物的铂族元素丰度值来判断岩盆深部铂族元素潜在成矿能力呢?这是本文试图回答的问题.