Effective use of a reservoir for paddy irrigation in tropical monsoon Asia—a case study of the Ngamoeyeik Project,Lower Myanmar

Irrigation projects with reservoirs have contributed to the stabilization of traditional rainfed rice and to the introduction of double-rice in monsoon Asia. This type of irrigation also has the capability of shifting the traditional rice-cropping season. This paper discusses the influences of the shifted cropping season on water resources and the effective use of the reservoir in the Ngamoeyeik Irrigation Project Area in Lower Myanmar. Synthesized streamflow data were applied to simulate water storage in the reservoir. The main results are as follows: (1) shifting the cropping season to avoid inundation problems can increase water availability, (2) the amount of evaporation loss in the reservoir water budget can be as high as 16%, which decreases water efficiency in the reservoir operation during the dry season, (3) a shifted cropping season is preferable under the special hydrological conditions found in Lower Myanmar.     

冬季亚麻杂草种类危害及防除研究

本文调查研究了州内亚麻种植地区的田块杂草种类、分布和发生规律。查清杂草共有101种，隶属25科，发生危害重的有7科26种，占25．74％；双子叶杂草77种，占76．23％，单子叶杂草22种，占21．78％，蕨类杂草2种，占1．98％。一年生杂草42种，占42．58％，越年或一年生杂草29种，占28．7l％，多年生杂草30种，占29．7l％。杂草随亚麻的播种而生长，至枞形期达最高峰，88—1231株／m^2。防治上在亚麻枞形期（株高5—10cm）、杂草2—3叶期选择50％敌草隆＋5％精喹禾灵或50％敌草隆＋56％二甲四氯钠盐，兑水喷雾，防除效果达90％以上。     

Microstructural and chemical investigation of subsurface hardened potatoes (Solanum tuberosum L.)

Summary Microstructural changes related to subsurface hardening of pre-peeled potatoes were investigated using cv. Sava potatoes peeled using an industrial peeler, a laboratory knife peeler or a hand knife peeler. The pre-peeled potatoes were packed in polymer bags and stored at 18°C for six days until cooking. Potato hardness and microstructure of the tissue was investigated. Cellulose and suberin in hard potato tissue increased linearly with increase in mechanical impact in a damage barrel. The area of cell walls and especially cell corners of mechanically damaged potatoes showed white autofluorescence in blue light. The number of layers of bricklike and autofluorescent parenchyma increased significantly with increasing hardness. Subsurface hardening was related to percentage cells with fluorescent gelatinised cell mass and curly cell walls in a depth of the potato tissue corresponding to the depth of maximum hardness.     

Economic injury levels for Bemisia tabaci (Homoptera: Aleyrodidae) in cotton: impact of crop price, control costs, and efficacy of control

Field studies were conducted during 1993 and 1994 in the Imperial Valley, California and Maricopa, Arizona to examine relationships between densities of Bemisia tabaci (Gennadius) populations and cotton (Gossypium hirsutum L.) yields, and to estimate economic injury levels (EILs) for pest management application. Populations of B. tabaci were manipulated by applying different numbers of insecticide applications in replicated plots. Resulting insect populations and cotton lint yields were used to develop damage functions and to estimate EILs for all life stages in relation to variable cotton prices, insecticide costs, and pest control efficacy. Economic injury levels declined with increasing cotton prices and increased as the cost of control increased, however, these changes were relatively small, based on typical ranges in price and control costs. In contrast, the efficacy of control provided by insecticide applications had a large influence on EILs, with lower efficacies being associated with higher injury levels. We developed a multiple regression model that accounted for the dynamic changes in the EIL in relation to crop price, control costs, control efficacy, and potential yield. Based on average prices and reasonable control costs and efficacy, EILs ranged from 5.9–15.2 adults/leaf, 6.1–19.8 eggs cm⁻², and 1.7–4.7 nymphs cm⁻² of leaf area. Additional research is needed to more closely relate the costs of control to the suppression of insect populations, and to define economic thresholds that will enable pest managers to maintain pest populations below EILs.     

基于机器视觉的作物多姿态害虫特征提取与分类方法

由于野外诱捕害虫的姿态存在多样性和不确定性,使得利用机器视觉进行害虫的自动识别与计数仍然是一个难题。该文提出一种基于颜色和纹理等与形态无关的特征相结合和利用多类支持向量机分类器的多姿态害虫分类方法。通过对目标害虫图像进行不同颜色空间特征、基于统计方法的纹理特征和基于小波的纹理特征的提取,构建了6组不同组合的特征向量。将10阶交叉验证的识别率作为适应度函数值,利用遗传算法对各组特征向量进行降维筛选。最后利用基于有向无环图多类支持向量机分类器对多姿态害虫进行识别和特征组选择。结果表明,遗传算法最多可以使特征向量维数降到原来的38.89%,基于HSV三通道颜色图像的小波纹理特征组在建模时间和平均准确率方面都表现最优,可以作为一种有效的多姿态害虫分类特征选择。     

基于卡尔曼滤波的橘小实蝇成虫运动轨迹优化跟踪

为了实现橘小实蝇虫口密度的精准监测,该文将机器视觉技术作为田间橘小实蝇成虫入侵自动化监测的感知方法。通过对监测区域内运动目标和背景的颜色分析,提出了基于卡尔曼(Kalman)滤波的运动目标颜色均值漂移跟踪算法,优化了多目标运动轨迹跟踪效果。该算法通过图像处理和匹配技术提取了橘小实蝇成虫在虫口监测区域二维平面X轴和Y轴方向上的位置坐标和速度分量,推算了橘小实蝇成虫运动轨迹递推关系。基于动态系统的状态序列线性最小方差估计理论和成虫运动轨迹关系分析,构建了卡尔曼滤波状态估计模型,并建立其预测和修正方程实现了橘小实蝇成虫运动目标位置估计。通过在虫口监测区域开展单目标和多目标分散及粘连条件下的成虫跟踪试验,试验结果表明颜色均值漂移跟踪算法对橘小实蝇成虫单目标跟踪具有较好的适应性,成虫监测计数准确率达100%,对于多目标分散和粘连情况跟踪处理效果较差,计数准确率分别下降至86%和76%;通过在颜色空间均值漂移跟踪算法的基础上引入Kalman滤波器估算目标运动的近似位置,实现了对橘小实蝇成虫分散和粘连多目标运动的持续跟踪优化,监测计数准确率分别提升至96%和93%。机器视觉技术实时跟踪橘小实蝇成虫在虫口监测区域运动轨迹试验进一步验证了橘小实蝇成虫虫口密度监测的可行性,为田间橘小实蝇成虫发生自动化监测技术研究提供了参考。     

灾害蝗虫附着系统爪尖的剪切强度测算

蝗虫爪尖能够形成用于稳固附着的机械锁合,抑制蝗虫在捕集滑板表面的滑移行为。为获取用于蝗虫捕集滑板研制的爪尖强度信息,利用自行设计的昆虫微力测试系统测试了蝗虫前足、中足、后足爪尖的剪切力;采用扫描电镜(scanning electron microscopy,SEM)分析了蝗虫爪尖及其断裂面的微形貌结构与几何特征,计算了爪尖断裂面的截面积,并据此测算了蝗虫爪尖的剪切强度。结果表明爪尖的剪切力介于197.4~243.6 mN,其中前足爪尖的剪切力最大,后足居中,中足最小;爪尖断裂面表现出层状的复合结构且具有显著不同的截面积(10 847.6~13 908.5μm2);测算结果表明蝗虫爪尖的剪切强度介于14.2~22.5 MPa。该研究可为研制具有良好滑移功能蝗虫捕集滑板提供参考,并可促进灾害蝗虫光电诱导滑移捕集技术的发展。     

基于证据理论和可变模糊集的成都市洪灾风险评估

洪灾系统的高维性和不确定性,给灾害风险评估带来较多困难,为了提高评估的准确性和合理性,实现科学灾害管理,该文将Dempster_Shafer证据理论应用到洪水灾害风险评估中,同时利用可变模糊集理论来构造证据理论基本信任分配,实现了客观合理的证据建模,最后利用经典组合原理进行证据组合。以成都市区2012年风险等级的计算为例,风险为高等级时的信任区间为[0,0.52],似然区间为[0,0.54],不确定大小为0.019,根据判断规则,确定市区2012年的洪灾风险等级为高。基于此方法采用相同处理,对研究区成都市风险等级的时空分布进行了计算分析。结果表明该方法能够较好地融合洪水灾害系统各方面信息以及处理风险评估中的不确定性,实现了洪灾风险的准确评估。     

论野生动物侵权的法律制度

野生动物的保护在近些年来备受关注,由于环境的逐渐恶劣,致使很多野生动物不得不离开原来的生长之地,从新寻找能够生存的栖息地。野生动物从曾经的远离人类,到现今的与人类争夺领地,这种现象不仅破坏了野生动物的生活轨迹,也扰乱了人类的正常生活,更直接致使野生动物的侵权案件频频发生。我国野生动物保护法于1989年开始实施。纵观这几十年来的实施状况,不难发现我国的野生动物保护法已经无法适应社会经济、生活环境的变化。如何协调保护人类的合法利益与保护野生动物之间的冲突问题日益严峻,但这一问题却是我国野生动物保护法中的一项缺失。因此,本文将着重阐述如何完善野生动物侵权的救济制度并给予合理的建议。     

植物凝集素在抗病虫害中的应用

植物凝集素是一类具有高度特异结合活性的蛋白,含有1个或多个可与单糖或寡聚糖可逆性特异结合的非催化结构区域。在简要介绍植物凝集素的定义、分类、特性的基础上,详细介绍从小麦胚芽、豌豆、半夏等植物中提取的植物凝集素在病虫害防治中的重要作用。