Egg Thiamine Status of Lake Ontario Salmonines 1995–2004 with Emphasis on Lake Trout

Alewives (Alosa pseudoharengus), the major prey fish for Lake Ontario, contain thiaminase. They are associated with development of a thiamine deficiency in salmonines which greatly increases the potential for developing an early mortality syndrome (EMS). To assess the possible effects of thiamine deficiency on salmonine reproduction we measured egg thiamine concentrations for five species of Lake Ontario salmonines. From this we estimated the proportion of families susceptible to EMS based on whether they were below the ED20, the egg thiamine concentration associated with 20% mortality due to EMS. The ED20s were 1.52, 2.63, and 2.99 nmol/g egg for Chinook salmon (Oncorhynchus tshawytscha), lake trout (Salvelinus namaycush), and coho salmon (Oncorhynchus kisutch), respectively. Based on the proportion of fish having egg thiamine concentrations falling below the ED20, the risk of developing EMS in Lake Ontario was highest for lake trout, followed by coho (O. kisutch), and Chinook salmon, with the least risk for rainbow trout (O. mykiss). For lake trout from western Lake Ontario, mean egg thiamine concentration showed significant annual variability during 1994 to 2003, when the proportion of lake trout at risk of developing EMS based on ED20 ranged between 77 and 100%. Variation in the annual mean egg thiamine concentration for western Lake Ontario lake trout was positively related (p < 0.001, r² = 0.94) with indices of annual adult alewife biomass. While suggesting the possible involvement of density-dependent changes in alewives, the changes are small relative to egg thiamine concentrations when alewife are not part of the diet and are of insufficient magnitude to allow for natural reproduction by lake trout.     

油气田施工企业如何办理特种设备的安装告知

随着长庆油田的不断发展,作为油气田产能建设施工企业,安装的锅炉压力容器和压力管道的数量逐年上升,对锅炉压力容器和压力管道的安装告知工作也日益成为工作中不可或缺的环节.文章介绍了长庆石油勘探局建设工程总公司近年来办理特种设备安装、改造、维修告知的做法和遇到的问题,如设备安装的监检费、安装告知书的内容和办理手续等.     

井下气液分离及回注技术研究现状分析

气井产水量的不断增加对天然气生产构成严重威胁，其影响越来越受到人们的关注和重视。使用井下气液分离及回注技术，可以降低举升和处理费用，增加生产寿命，提高采收率，减少环境污染，简化地面分离设备，提高投资效益。针对井下分离及回注技术研究现状进行了分析，给出了并下气液分离及回注形式、适用条件和技术设计、应用方面的结论。     

杜84断块超稠油开发中后期稳产对策研究

对杜84断块超稠油生产中后期暴露的主要矛盾，即随着轮次升高，周期吞吐效果变差，井下技术状况日益变差。油层动用不均，汽窜加剧等问题进行了分析。并提出了相应的稳产对策-实施多井整体吞吐，大修复产，调剖等措施。现场应用证明，这些措施基本能够确保杜84断块超稠油中后期的稳产。     

电子封装用金属基复合材料的制备

分析了电子封装用金属基复合材料的性能特点及其对制备工艺的要求，在此基础上论述了该种材料的各种制备工艺的特点及发展现状。     

国产550MW水轮发电机用新材料和新工艺

介绍了二滩水电站 5 5 0MW机组发电机定转子绕组方面所采取的新结构、新工艺和新材料     

风云变幻的德国有线电视市场

德国电信是德国有线电视市场最大的运营商，无力对庞大的网络进行升级改造，欲将其网络出售给海外公司，以便解决自己的债务问题。海外公司之间的竞争以及相关管制机构的干预，导致了市场运作复杂多变的局面。     

Call admission control schemes under generalized processor sharing scheduling

Provision of Quality‐of‐Service (QoS) guarantees is an important and challenging issue in the design of integrated‐services packet networks. Call admission control is an integral part of the challenge and is closely related to other aspects of networks such as service models, scheduling disciplines, traffic characterization and QoS specification. In this paper we provide a theoretical framework within which call admission control schemes with multiple statistical QoS guarantees can be constructed for the Generalized Processor Sharing (GPS) scheduling discipline. Using this framework, we present several admission control schemes for both session‐based and class‐based service models. The theoretical framework is based on recent results in the statistical analysis of the GPS scheduling discipline and the theory of effective bandwidths. Both optimal schemes and suboptimal schemes requiring less computational effort are studied under these service models. The QoS metric considered is loss probability. This revised version was published online in June 2006 with corrections to the Cover Date.     

浅谈城市照明监控系统的开发设计

介绍LEAD-2000城市照明监控制系统的设计探索及运行效果。     

等离子体技术及其在“三废”处理中的应用

阐述等离子体的概念、分类、特点和作用机理,从大气污染、水污染、固体废物治理三个方面简述在"三废"处理中各种等离子体技术的应用及特点,分析其存在的问题,展示了等离子体技术在环境保护中的应用前景.