平面贴片天线的研究

介绍了半波谐振贴片的理论,并利用HFSS分别对采用微带和同轴两种方式馈电的中心频率为12GHZ的平面贴片天线进行了仿真.仿真结果表明:当改变微带与同轴传输线馈电位置时,对于微带馈电方式,要实现单频点,取贴片的长边中点效果较好;如果偏离该中心点,将具有双频点特性.而采用同轴馈电时,所研究的几个馈电点位置中也是贴片长边中点相对较好,如偏离该中心点,频率将偏离中心频率.     

斜带石斑鱼(Epinephelus coioides)两种神经肽NPB的发现及表达分析

神经肽B(Neuropeptide B,NPB)在生命体的许多生理活动中发挥着重要作用,如调节摄食行为、能量平衡、睡眠、神经内分泌功能和调节炎症性疼痛等。为了研究在石斑鱼中NPB与摄食调控的关系,本文对斜带石斑鱼(Epinephelus coioides)转录组数据比对分析后,在斜带石斑鱼中克隆得到了两种NPB(NPB1和NPB2)基因的c DNA序列,首次发现鱼类存在两种NPB基因。作者对NPB编码蛋白的信号肽及其成熟肽的结构进行了预测,发现与其它脊椎动物相一致。采用实时荧光定量PCR技术,研究了斜带石斑鱼不同组织中的m RNA的表达模式,结果发现NPB1和NPB2在脑组织中广泛表达,且在下丘脑中表达最为丰富;在其它的外周组织器官中也有相应的表达。饥饿试验的研究结果表明,在禁食3d和7d后,NPB1和NPB2的m RNA表达量都发生了显著的下调;复投喂后表达量恢复。由此可见NPB1和NPB2参与了斜带石斑鱼摄食行为的调节。     

Partitioning of the feeding niche along spatial,seasonal and size dimensions by the fish community in a tropical Bay in Southeastern Brazil

Feeding guilds and spatial, seasonal and ontogenetic changes in the diets of 24 fish species in a tropical bay in Southeastern Brazil were examined. The hypotheses tested were that groups of species form specific trophic guilds and that the feeding partitioning differs along the niche dimensions. Five trophic guilds (Polychaeta, Copepoda, Teleostei, Teleostei/Crustacea and Polychaeta/Crustacea) and two species with specialised feeding, one teleost (Aspistor luniscutis) and one bivalvia (Sphoeroides testudineus), were found. Polychaeta was the most important resource for nine fish species, followed by Copepoda (6 spp.), Teleostei (5 spp.) and Caprelidae Amphipoda (3 spp.). Polychaeta was the most used resource for species in the inner bay zone, and Crustaceans in the outer bay zone. We detected a predominance of Polychaeta between the spring and autumn, whereas crustaceans were consumed at a greater rate in the winter. The most conspicuous changes in diet occurred along the spatial and seasonal dimensions, rather than the size dimensions. The hypotheses tested were accepted. Identifying and incorporating information about the bay food web is a first step towards developing management strategies that are sensitive to this particular ecosystem.     

Exploring composition and behaviour of fish fauna by in situ observations in the Bari Canyon (Southern Adriatic Sea,Central Mediterranean)

Canyons play a fundamental role in enhancing the abundance and diversity of marine organisms through the transport of organic matter and food resources, the presence of complex physical habitats and the absence of trawl fishing. During four baited lander deployments carried out in the Bari Canyon (Southern Adriatic Sea, Central Mediterranean), at depths of 443–788 m, about 43 h of video records were taken, for a total of 619,200 video frames. A total of 12 benthopelagic fish species (five chondrichthyes and seven osteichthyes) were identified. The blackspot seabream (Pagellus bogaraveo) was the most often observed fish species. The depth of 787 m represents a new depth record for this fish in the Adriatic Sea. Groups of up to 40 individuals of P. bogaraveo were attracted to the bait and were shown in single frames. The individuals were observed both exploring the area and feeding actively on the bait. The European conger (Conger conger) was recorded at each deployment. Clear scavenger behaviour was also observed in this teleost fish and in the shark Etmopterus spinax. The shark species Centrophorus granulosus and Hexanchus griseus, which are considered ‘vulnerable’ on the published IUCN Mediterranean Regional Red List, were also recorded but, although attracted by the bait, they were never seen feeding on it. Other fish species, harvested on fishing grounds, such as Merluccius merluccius, Helicolenus dactylopterus and Polyprion americanus, were also recorded. This study represents the first in situ documentation, at very low impact, of the fish fauna in the Bari Canyon, providing new insights into its small scale distribution and behaviour, the first in situ direct observation of the variable feeding behaviour of P. bogaraveo and its gregarious habits, as well as indicating that this canyon could act as a refuge area for species that are vulnerable to fishing on the open slope.     

Afforestation and stream temperature in a temperate maritime environment

There have been few long term investigations of the effects of afforestation on stream temperatures in the UK, and the present study uses the results of continuous monitoring of water temperatures in a forest and a moorland stream of the Loch Grannoch area in southwest Scotland over a 4 year period to investigate the effects of planting coniferous forest on stream thermal regime. The presence of a coniferous tree canopy resulted in a lowering of mean water temperatures by ～0·5 °C but larger reductions in summer monthly mean maxima and diel ranges of up to 5 °C and 4 °C respectively. The diel cycle in the forested stream lagged behind that of the moorland site in all months of the year, but the delay in timing was greater for the peak than for the trough in the diel cycle. Mean water temperatures were higher in the forest stream during the mid‐winter months, reflecting higher minimum values. Contrasts in stream thermal regime between forest and moorland showed relatively little interannual variability over the study period. Continuous monitoring of air temperatures during 2002 revealed contrasts between the study sites that were less pronounced for air than for water temperature, and suggested it is the shading of incoming solar radiation that has a strong effect in determining the water temperature behaviour of the forested stream. Although the biological impact of the observed contrasts in stream temperature between land uses is likely to be relatively modest, the presence of forest cover moderates the occurrence of high summer temperatures inimical to the survival of some salmonid species. Copyright © 2005 John Wiley & Sons, Ltd.     

AVAILABILITY OF PHOSPHORUS FROM SELECTED INORGANIC PHOSPHATES TO JUVENILE ABALONE,HALIOTIS DISCUS HANNAI INO.

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贝类养殖对海湾生态系统的影响

本文描述了海水养殖贝类生态的主要特点,重点讨论了高密度贝类生物沉降过程以及对浮游植物的摄食控制等过程的生态效应。通过文献综述和个例分析,论述了贝类养殖对海湾生态系统的影响。本研究对贝类养殖业持续发展及沿海环境的保护均具有重要意义,文中还就今后的研究及方法学提出了建议。     

Killer whales in South African waters—a review of their biology

The distribution, seasonality and schooling behaviour of killer whales Orcinus orca in South African waters have been investigated from 785 records compiled between 1963 and 2009, and their size, morphometrics, growth, reproduction, food and feeding behaviour described from the examination of 54 individuals, 36 of which were landed at the Durban whaling station between 1971 and 1975. Qualitatively, the species appears to be more frequently encountered offshore, where it forms small schools of generally less than six animals. Seasonality of occurrence is not marked, although circumstantial evidence indicates that some individuals migrate from higher latitudes. Males reach 8.81 m and females 7.9 m, with 16.2% of males exceeding the size of the largest female. Stomach content and observational data suggest that the species can be characterised locally as an opportunistic predator of megavertebrates, rather than as the fish-feeding ecotype previously described. A stranded adult male with extreme tooth wear that was 1.5–2 m shorter than other males of equivalent age may be representative of a separate ‘offshore’ ecotype. Apparent differences between features of the popu lation's life history and those of resident killer whales in the north-eastern Pacific might be attributed to either uncertainties in age determination using dentinal growth layer groups or sampling bias. The basis for the suggestion that killer whales in South African waters should be reclassified as Vulnerable (rather than Data Deficient) is challenged.     

沙漠地区资源高精度三维地震勘探技术应用

内蒙古毛乌素沙漠西南边缘勘探区，地表大部分为固定、半周定沙丘．少部分为随季风流动的供状沙丘及新月型沙丘，地形起伏剧烈。该勘探区存在着检波器耦合难、实施变脱难、地震浒号屏蔽作用姓、心始记录面貌差、干扰波复杂、资料处理难度大等问题。为此采取了加长检波器尾锥、加大井深和药量、综合应用多种静校正技术以及与提高信噪比为主的资料处理流程等技术措施，经验证术措施采用合理，勘探成果准确可靠。