Catch performance of the small prawn pot in terms of entry and escape of the Oriental river prawn Macrobrachium nipponense

ABSTRACT: The entry and escape behavior of prawn Macrobrachium nipponense in relation to the pot may be controlled both by its design and population process in the pot's given interior space. To obtain the basic data on how the population process affects the number of individuals in the pot without bait, a comparative study of the experimental results obtained in the actual fishing ground and calculated values was conducted. The variation pattern in the number of individuals in a pot was consistent with that of the calculated value. The model equation proposed in this study might be effective for evaluating the daily variations in the number of individuals in a pot. The results suggest that both the population process and the pot's design control the entry and escape behavior of the prawn.     

Monitoring tigers with confidence

With only 5% of the world's wild tigers (Panthera tigris Linnaeus, 1758) remaining since the last century, conservationists urgently need to know whether or not the management strategies currently being employed are effectively protecting these tigers. This knowledge is contingent on the ability to reliably monitor tiger populations, or subsets, over space and time. In the this paper, we focus on the 2 seminal methodologies (camera trap and occupancy surveys) that have enabled the monitoring of tiger populations with greater confidence. Specifically, we: (i) describe their statistical theory and application in the field; (ii) discuss issues associated with their survey designs and state variable modeling; and, (iii) discuss their future directions. These methods have had an unprecedented influence on increasing statistical rigor within tiger surveys and, also, surveys of other carnivore species. Nevertheless, only 2 published camera trap studies have gone beyond single baseline assessments and actually monitored population trends. For low density tiger populations (e.g. <1 adult tiger/100 km²) obtaining sufficient precision for state variable estimates from camera trapping remains a challenge because of insufficient detection probabilities and/or sample sizes. Occupancy surveys have overcome this problem by redefining the sampling unit (e.g. grid cells and not individual tigers). Current research is focusing on developing spatially explicit capture-mark-recapture models and estimating abundance indices from landscape-scale occupancy surveys, as well as the use of genetic information for identifying and monitoring tigers. The widespread application of these monitoring methods in the field now enables complementary studies on the impact of the different threats to tiger populations and their response to varying management intervention.     

Visual acuity of Pacific Saury <Emphasis Type="Italic">Cololabis saira</Emphasis> for understanding capture process

ABSTRACT:   To understand the mechanism of the behavioral response in the capture process of how fish recognize fishing gear and then how they can avoid the gear, the visual acuity of Pacific saury Cololabis saira was investigated by histological examination of the retina of individuals in the size range of 75–365 mm fork length (FL). The contour map of cone density distribution shows that the highest cone density is located in the temporal area of the retina, which indicated the visual axis as the forward direction. The visual acuity (VA) depends both on the focal length of the lens and the number of cones in the retina. The lens diameter increased linearly from 1.40 to 4.73 mm with fish growth, while the cone density decreased gradually from 765 to 378 cells/0.01 mm². Our results show that the visual acuity increases proportionately from 0.057 to 0.140 for individuals ranging in FL from 75 to 365 mm as expressed by the equation VA  = 0.0065 ×  FL ^0.5271 ( r ² = 0.9624).     

IPv6网络流量的分布式采集与分析

IPv6网络的分布式流量采集与分析系统把流量的实时监控和数据库技术相结合,为网络管理者提供有效的决策支持.系统主要功能定位于IPv6网络的流量采集、实时分析和流量分析,其工作环境是高速局域网,链路层的物理媒介是双绞线或光纤链路.系统包含采集分析子系统、流量分析子系统和网络管理子系统.本文提出了基于数据库技术的IPv6网...     

江淮地区稻–麦周年产量差及其与资源利用关系

江淮地区是我国水稻和小麦重要的生产基地,明确该地区不同产量水平之间的差异特征及形成机制,探索区域粮食生产的限制因子,可为缩减江淮地区周年产量差的技术途径提供科学依据和参考。本研究以稻–麦周年生产体系为研究对象,定量分析不同产量水平田块之间的产量差与气候影响因素。结果表明,江淮地区水稻、小麦及周年农户水平与试验水平和高产纪录间存在显著的产量差,分别为3315.9、1537.5、4645.6 kg hm–2和7498.6、3977.9、9840.9 kg hm^–2。水稻、小麦及周年农户水平较试验水平还有46.2%、29.7%和37.3%的增产潜力,较高产纪录还有104.5%、77.0%和79.0%的增产潜力。每穗粒数是造成水稻产量差的主要因子,穗数和每穗粒数是造成小麦产量差的主要因子。与农户水平相比,水稻试验水平和高产纪录的穗粒数分别增加30.4%和116.1%;小麦试验水平和高产纪录的穗数和每穗粒数平均分别增加40.9%、70.0%和21.8%、19.6%。缩小产量差水稻主要依赖于增加每穗粒数,小麦靠穗数和每穗粒数的协同提高。生育期累积辐射和积温较低是导致水稻产量差异的主要气候因素,而生育期降雨过多是导致小麦产量差异的主要气候因素。根据研究提出了“强稻稳麦”是提升江淮地区周年粮食生产的有效途径。     

气相色谱法测定城市污泥中多氯联苯与有机氯农药

建立了以丙酮和石油醚超生提取,用硫酸尧高纯铜粉和硅胶柱净化的可同时检测长江三角洲地区城市 污泥中有机氯污染物的气相色谱法。与传统方法相比,在保证足够准确度尧精确度和灵敏度的前提下,该方法具有前 处理简单尧测定成本低尧样品用量少的特点,且可同时测定城市污泥中有机氯农药（OCPs）和多氯联苯类（PCBs）化合 物。应用该方法对我国长江三角洲地区城市污泥中PCBs 和OCPs 进行测试,结果表明,方法最低检出限为0.09~ 0.33 滋g/kg,达到了微量分析要求。加标回收试验中,PCBs 回收率为59.50%~101.51%,OCPs 回收率为57.21%~ 89.62%,相对标准偏差为1.89%~14.67%。     

Probarbus jullieni and Probarbus labeamajor: the management and conservation of two of the largest fish species in the Mekong River in southern Laos

• 1. Probarbus jullieni and Probarbus labeamajor are two of the largest carps in the Mekong River Basin, each reaching a maximum weight of about 70 kg. P. jullieni is listed in Appendix 1 of the Convention on the International Trade in Endangered Species, and both are listed on the IUCN Red List of Threatened Species, the first as ‘endangered’ and the second as ‘data deficient’.
• 2. Six years of quantitative monitoring of a large‐meshed gill net fishery for Probarbus just below the Khone Falls in Khong district, Champasak province, in southern Laos shows that 78% of the overall catch is comprised of Probarbus, with P. jullieni making up 65% of landings.
• 3. Over the 6‐year period catches of Probarbus declined significantly. However, catch‐per‐unit effort statistics do not indicate that the fishery is in decline, although fishers are convinced that real stock reductions are a large part of the reason for catch declines and decreases in fishing effort.
• 4. A number of ecological and social factors are affecting the number and quality of gill nets in use, the length of fishing seasons, and gill net efficiency, making it difficult to compare catch‐per‐unit effort between years.
• 5. There has been a shift from using large‐meshed gill nets for catching Probarbus to targeting smaller species using gill nets with smaller mesh‐sizes. This is an example of the ‘fishing down’ of a Mekong fish community, in which large long‐lived species are the first to be affected by heavy fishing pressure.

Copyright © 2006 John Wiley & Sons, Ltd.     

Mucin biosynthesis in the bovine goblet cell induced by Cooperia oncophora infection

Mucin hypersecretion is considered to be one of the most common components of the immune response to gastrointestinal nematode infection. However, investigations have not been conducted in the Cattle–Cooperia oncophora system to verify the findings largely derived from murine models. In this study, we examined the expression of seven mucins and seven enzymes in the mucin biosynthesis pathway involved in O-linked glycosylation in the bovine small intestine including goblet cells enriched using laser capture microdissection during a primary C. oncophora infection. At the mRNA level, MUC2 expression was significantly higher in both lamina propria and goblet cells at 28 days post-infection compared to the naïve control. MUC5B expression at the mRNA level was also higher in lamina propria at 28 dpi. Expression of MUC1, MUC4, MUC5AC, and MUC6 was extremely low or not detectable in goblet cells, columnar epithelial cells, and lamina propria from both naïve control and infected animals. Among the seven enzymes involved in post-translational O-linked glycosylation of mucins, GCNT3, which may represent one of the key rate-limiting steps in mucin biosynthesis, was up-regulated in goblet cells, columnar epithelial cells, lamina propria, and gross small intestine tissue during the course of infection. Western blot analysis revealed that MUC2 glycoprotein was strongly induced by infection in both gross small intestine tissue and its mucosal layer. In contrast, the higher MUC5B protein expression was observed only in the mucosal layer. Immunohistochemistry provided further evidence of the mucin glycoprotein production and localization. Our results provided insight into regulation of mucin biosynthesis in various cell types in the bovine small intestine during gastrointestinal nematode infection and will facilitate our understanding of mucins and their role in immune response against parasitic nematodes.     

快速检测动物病毒电镜技术

经多年研究，提出了适用于快速检出和鉴定动物病毒的系列电镜样品制备技术。该技术包括离子交换捕捉、微波幅射、高速离心、免疫金标方法。通过与常规法对比试验证实了离子交换捕捉法具有防腐保鲜作用，其浓缩样品的程度相当于超速离心法，简便易行，适用于远距离运送样品的检测；微波幅射改进法，不但加快了包埋制样速度，而且也提高了包埋质量；高速离心沉淀法快速简便，提高了检出率；免疫金标法不但提高了检出率，而且对于非典型及形态特征性不强的病毒粒子也能作出准确的诊断。可根据不同种类、不同目的的样品采取不同的制样方法，形成了系列化技术。此技术经农牧区、边疆、兽医生药厂、高等院校、科研单位以及海关进出口检疫等送检样品的验证，完全是可行的。应用该技术可快速、准确地诊断动物病毒病。     

封存CO_2泄漏量对三叶草生长的影响

随着碳捕集与封存技术在中国的逐步发展,封存CO2泄漏对农田生态系统的潜在威胁日益引起关注,而目前对CO2泄漏时作物的适应能力认识仍不足。选择分布广、耐酸性强的三叶草作为研究对象,设对照(不通CO2)和采用栽培箱底部通入500、1 000、1 500和2 000 g/(m2·d)CO2 5个处理,系统评估三叶草对封存CO2泄露的响应。结果发现:在500 g/(m2·d)的CO2泄露情景下,三叶草的生物量、根系活力、营养成分等主要生理指标略有增加或保持稳定,表现出较好的适应能力。随着CO2泄漏量增加到1000 g/(m2·d)以上,三叶草的生物量、根系活力下降,逐步表现出受环境胁迫的特征。在CO2通量处理下土壤pH值在6.80~7.04之间,高于三叶草适宜生长的pH值下限。研究表明,三叶草对封存CO2泄露具有较好的适应能力,为封存CO2泄露应对技术研究提供参考。