广东省稻菜轮作区中牛筋草对十种除草剂的抗性水平及靶基因序列分析

为明确广东省稻菜轮作区中牛筋草对10种常用除草剂的抗性水平及抗性分子机制,采用整株生物测定法测定广东省稻菜轮作区内8个牛筋草种群P1～P8对草甘膦、草铵膦和乙酰辅酶A羧化酶(acetyl-CoA carboxylase,ACCase)抑制剂类等10种除草剂的抗性水平,并进一步分析P1和P8种群相关靶标酶基因5-烯醇丙酮酰莽草酸-3-磷酸合酶(5-enolpyruvyl-shikimate-3-phosphate synthase,EPSPS)、谷氨酰胺合成酶(glutamine synthetase,GS)和ACCase的部分功能区序列特征。结果显示,牛筋草P1～P8种群对草甘膦抗性指数为敏感种群的5.9倍～17.7倍,其中P8种群对草甘膦的抗性水平最高;8个种群对草铵膦也产生了不同程度的抗性,抗性指数为敏感种群的2.3倍～14.2倍,其中P1种群抗性最高。牛筋草P1和P8种群均对ACCase抑制剂类除草剂精喹禾灵、氰氟草酯和噁唑酰草胺产生了交互抗性;P1种群ACCase基因在第2 041位氨基酸处发生突变,该突变在牛筋草种群中首次发现;而P8种群ACCase基因则在第2 027位氨基...     

两种沉水植物在不同水深和生长时期对入侵植物的响应

为研究沉水植物在不同水深和生长时期对不同种类入侵植物的响应,选取2种湿地入侵植物凤眼莲Eichhornia crassipes、水盾草Cabomba caroliniana和2种常见本地沉水植物黑藻Hydrillaverticillata、菹草Potamogeton crispus为研究对象,通过模拟试验探究在不同水深（0.2、0.4 m）和生长时期（生长初期和生长旺期）的本地沉水植物对2种入侵植物的响应。结果显示,当水深为0.4 m时更有利于黑藻的生长,并可削弱入侵植物对黑藻生长的消极作用,而水深对菹草的生长无显著影响;入侵植物种类对本地沉水植物的生长无显著影响,但影响方式却存在差异,其中水盾草倾向于直接抑制本地沉水植物的生长,而凤眼莲可以通过降低水体透明度以及总磷含量进而间接抑制本地沉水植物的生长。此外,外来植物在本地沉水植物生长初期入侵对本地沉水植物产生的消极影响较生长旺期入侵时更显著。表明凤眼莲及水盾草入侵对本地沉水植物生长的影响机制存在差异,本地沉水植物在适宜水深和生长旺期对2种入侵植物具有更强的抵抗能力。     

海河二道闸和防潮闸优化调度研究

汛期为腾空海河河道并保证二道闸下咸水不致上溯，二道闸闸下水位应控制在1.0m左右。利用一维非恒定流模型对海河自西河闸至入海口河段进行数值模拟，研究了西河闸分流量为80、100、120m3/s3种情况下，海河防潮闸和二道闸优化调度结果。     

用层次分析法决策喷灌规划设计方案

在喷灌工程规划设计过程中,正确地选用规划设计方案,实际是一个综合分析决策的过程。主要应考虑的因素中,有些可定量,有些则是无法定量的。如何对非定量因素作定量分析,进而对整个喷灌规划设计方案作出评价决策,层次分析法是解决这类问题简洁、有效、实用的方法。     

Review on the measurement theories of enterprise knowledge management during the past three years in China

The implement of enterprise knowledge management gives rise to extensive research on its measurement. Based on the existing measurement theories and evaluation index systems of enterprise knowledge management during the past three years in China, this paper analyzes the problems in measuring target and designing the evaluation index system in the existing research findings, and explains detailedly why measurement target of enterprise knowledge management should be "level evaluation" instead of "performance evaluation", and definitely points out the meanings of enterprise knowledge management level and significance of its evaluation. This paper also indicates that the design of the evaluation index system should be complete, reasonable, proper and operable.     

EPQ Model with Different Lost Sale Factor Relative to Inventory Level

It is important for enterprises' inventory management to find out the optimal production cycle and the length of shortage time,so that the total cost of inventory system can be reduced and the service level can be raised.Based on the classical EPQ model,this paper develops an EPQ model for deterioration items with different lost sale factor relative to the inventory level during shortage period.The existence of unique optimal solution is discussed by mathematic analysis and a numeric example.The sensitivity analysis shows that the parameter of losing sale has different impact on the costs of inventory system.The factors must be considered for the production inventory system to make management decision.     

The quality of service provided by the irrigation department to the users associations, Tunuyan System, Mendoza, Argentina

The quality of service provided by the provincial Irrigation Department (DGI) to the Water Users Associations (UA), and subsequently by the UA's to the related water users, is based on the provincial water law. The intended volume of water being delivered per considered period further depends on the water availability and on the (crop irrigation) water requirements. The Service Level (SL) compares the intended water supply with the water supply that would be required to supply the entire irrigable area with sufficient water. As soon as the intended water delivery pattern is set, the measured actual delivery can be assessed against the intention. Several performance indicators are used in this context. Based on the assessment of the Water Delivery Performance Ratio and the Overall Consumed Ratio recommendations are made on changes which can be made to improve water use and reduce problems of waterlogging.     

水井酸处理效果预测研究

水井酸处理效果预测一直缺乏成熟的方法。提出了根据水位恢复曲线形态和含水层裂隙特征来预测井的首次酸处理效果，经与石油界所用方法有明显不同。石油界普遍认为，只有不位恢复曲线为快速上翘型的低产碳酸盐岩井才适合酸处理（即基质酸化），但作者近年来发现，多数水位恢复曲线为直线型的低产碳酸盐岩井，即井中含水层裂隙平均宽度＜5mm的井，酸处理效果也很好，被调查3眼这类井的单位涌水量增加值平均为423％；水位恢复曲线为缓慢上翘型的井中，部分含水层裂隙被松散物充填的井，采用特殊的酸处理方法处理后，井的单位涌水量可增加100％。另外，采用适当的方法，使用足够数量的酸进行首次酸处理后，水井再进行酸处理一般效果都很差。