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.     

EXTENSION OF THE RELATIONAL DATABASE AND ITS ALGEBRA WITH ROUGH SET TECHNIQUES

This paper describes a database model based on the original rough sets theory. Its rough relations permit the representation of a rough set of tuples not definable in terms of the elementary classes, except through use of lower and upper approximations. The rough relational database model also incorporates indiscernibility in the representation and in all the operators of the rough relational algebra. This indiscernibility is based strictly on equivalence classes which must be defined for every attribute domain. There are several obvious applications for which the rough relational database model can more accurately model an enterprise than does the standard relational model. These include systems involving ambiguous, imprecise, or uncertain data. Retrieval over mismatched domains caused by the merging of one or more applications can be facilitated by the use of indiscernibility, and naive system users can achieve greater recall with the rough relational database. In addition, applications inherently “rough” could be more easily implemented and maintained in the rough relational database.     

更好的浏览器

就性能而非市场份额来说,Opera一直是MicrosoftInternet Explorer的强有力的替代产品在过去两周,我一直在使用Opera 7.1作为我的主要浏览器。我想说它给我的印象深刻。就性能而非市场份额来说,Opera(www.opera.com) 一直是Microsoft InternetExplorer的强有力的替代产品。我感觉Opera比IE要快,并且它还有一个很棒的下载管理器,在一个单独的屏幕上保留着下载文件。再加上一个弹出式阻截器和带有标签的界面,可以将你打开的页面限定在Opera主窗口内。多元搜索窗口把你的搜索请求发送到Google 和AlltheWeb,然后在并列的窗口显示结果。对O…     

2003年采购指南

现在名牌笔记本电脑也卖到1000美元以下了,你也该想想你的下一台PC是否应该是笔记本     

Using network hacking techniques to disrupt military operational networks

It starts in a small way. An Internet-originated electronic mail message received by various technical ratings and Combat Information Center (CIC) officers on a ship deployed in a very high threat area of the Persian Gulf relays news of a natural disaster involving their families that supposedly occurred during a cookout:     

3G移动电话的系统级LSI

引言 无线移动电话仅具备语音功能的时代已经离我们远去了.目前的3G手机更多的是作为多媒体系统,提供彩显、游戏、音频、视频、相机、蓝牙、GPS、WLAN、高速广域数据服务以及其他高级特性.由于功能非常之多,因此处理新型3G电话比处理仅有语音功能的2G电话要复杂5倍至10倍,在应用处理方面则要求更高.     

基于FPGA设计航空电子系统

基于现场可编程门阵列(FPGA)核心的实施体现了先进的现代航空电子设计方法。这项技术具有多种优势,如废弃组件管理、降低设计风险、提高集成度、减小体积、降低功耗和提高故障平均间隔时间(MTBF)等,吸引着用户将原来的系统转移到此项技术。MIL-STD-1553的市场可能随着这种趋势而繁荣起来;事实上,某些客户已经觉得这项技术的实施有点姗姗来迟。MIL-STD-1553核心带来了多种好处,它代表着彻底告别了ASIC传统。FPGA中加入一项知识产权核心,就获得了一种与众不同的特性,而成为一个非常专业的高级子系统。这为增强MIL-STD-1553的设…     

通用双热交换控制器允许带电底板插入

引言当把电路板插入带电底板时,由于板上旁路电容充电而从底板电源总线吸入大的瞬态电流。瞬态电流可毁坏电容器、连接器引脚、板迹线以及系统电源,导致系统中其他板复位。新的双通道LTC1645热交换控制器是设计用于控制电路板电源电压,防止系统电源上假信号和对板的毁坏。LTC1645的两个通道可分别设置为上升或下降方式,或同时编程为上升方式,确保两个输出上的电源跟踪。用外部N一沟通路晶体管,电源电压可随可编程速率跃变。两个高瑞开关驱动器控制外部N沟道FET栅极,电源电压范围12V～12V。可编程电子电路断路器防止输出短路。L…