Effect of uneven application of azadirachtin on reproductive and anti-feedant behaviour of Rhyzopertha dominica (Coleoptera: Bostrichidae)

The effects of uneven application of an azadirachtin-enriched neem extract to wheat grain on the reproduction and feeding behaviour in Rhyzopertha dominica (F) were investigated. The evenness of distribution amongst individual wheat grains during grain treatment was not important in ensuring its effectiveness as an anti-feedant or as an insect growth regulator, provided that, overall, the grain was treated with an effective level of azadirachtin. The effect of azadirachtin on reproduction was not improved when the diluent application rates were increased from 0.5 ml kg⁻¹ to 5 ml kg⁻¹. Treating 10% of the grain was shown to provide the same level of protection as treating 100% of the grain. The anti-feedant effect of azadirachtin on the beetle was also unaffected by unevenness of treatment, provided that 50% of the grain was treated. The fact that azadirachtin remains effective even when application to grain is uneven may be advantageous in field situations where uniform distribution of insecticides is difficult to achieve. © 1999 Society of Chemical Industry     

太白山佛爷池湖泊沉积理化分析反映的8000aBP以来环境变化

封闭湖泊沉积物比较完整地记录了环境演化信息,是研究古环境变化的理想材料。通过对太白山佛爷池湖心剖面沉积物样品粒度参数、总有机碳、有机碳同位素、（TiO₂/K₂O）、碳酸盐含量等气候环境代用指标的分析,结合剖面的岩性特征与¹⁴C测年,指出本区气候环境经历了四个变化阶段:（1）8200aBP～5900aBP的温暖潮湿阶段,出现较为适宜的气候;（2）5900aBP～4400aBP气候变得恶劣,较为冷干;（3）4400aBP～2700aBP气候恢复为温湿类型;（4）2700aBP以后气候再一次急剧变冷干,大至到900aBP逐渐变得温湿,与太白山地区现代气候类型相符。     

贵州黔西南红土型金矿苔藓植物的调查

为了探明黔西南红土型金矿苔藓植物种类,为进一步利用苔藓植物作为先锋植物研究红土型金矿区植被修复提供较好的材料,采用梅花采样法对黔西南18个红土型金矿苔藓植物进行全面调查、收集、鉴定。结果表明:金矿区共有苔藓植物14科53属124种,其中,苔类植物1科1属2种,藓类植物13科52属122种;金矿区苔藓植物共有12种区系类型,以世界广布种占主体;金矿区苔藓植物丰富度指数、种相似性指数均较低,苔藓植物生活型主要以矮丛集型为主;在18个矿中寻找到5种广泛分布的苔藓植物种类:银叶真藓(Bryum argentenm)、卵蒴丝瓜藓(Pohlia proligera)、纤枝短月藓(Brachymenium exile)和土生对齿藓(Didymodon vinealis)、硬叶小金发藓(Pogonatum neesii)。     

对国有商业银行存款定价问题的研究

利率市场化改革的重要方面，存款利率的市场化改革正稳步推进，这无疑给各商业银行特别是4大国有商业银行带来巨大的风险和机遇。本文主要就4大国有商业银行利率风险管理的重要组成部分——存款定价管理进行深入分析。探究存款定价的制约因素、原则，并提出以账户管理成本、边际成本、上层目标为基础的存款定价方法。以求增强国有商业银行存款市场化管理能力，为国有银行的真正商业化经营、股份制改造创造条件。     

静电喷嘴雾化特性与沉积效果试验分析

为了探究电极材料对静电喷嘴雾化效果和荷电性能的影响,确定设计的静电喷嘴的最佳作业参数,并明确静电作用对雾滴沉积效果的影响,以电极材料、电极电压、喷施压力和喷孔直径为喷施变量,针对设计的静电喷嘴进行室内雾化和沉积试验。研究结果表明:设计的静电喷嘴最佳电极电压为8 k V,最佳电极材料为紫铜,最佳喷施压力为170 k Pa;相比于非静电喷雾,静电作用开启后,静电喷嘴的有效喷幅增加约50 cm;在3个采样层的雾滴沉积密度依次增加了23、19、10个/cm2;在喷嘴雾化的所有雾滴中,粒径在50~120μm区间的雾滴受静电作用影响最大,静电作用开启后,此区间段内的雾滴沉积数量增加了约2倍,当雾滴粒径大于120μm时,雾滴沉积密度随雾滴粒径的增大呈下降趋势;沉积的雾滴主要是粒径在180μm以下的雾滴,因此适合最佳生物粒径为180μm及180μm以下的作物。     

穴位接种IBD双价细胞苗鸡的抗原定位及免疫活性细胞监测

１５日龄滨白鸡后海穴接种鸡传染性法氏囊病（ＩＢＤ）双价细胞苗，采用免疫荧光组化跟踪抗原定位和免疫活性细胞的免疫形态学监测，以评价其免疫效果。同时与口服和肌肉免疫途径进行了对比试验。结果表明，后海穴穴位免疫优于口服免疫和肌肉免疫。本文对穴位免疫机制进行了探讨     

植保无人机低空低容量喷雾在茶园的雾滴沉积分布及对茶小绿叶蝉的防治效果

为研究植保无人机低空低容量喷雾技术在实现茶园农药减量中的作用,通过在茶园喷施20%吡虫啉可湿性粉剂,比较其与传统大容量喷雾技术对茶小绿叶蝉Empoasca flavescens的防治效果。结果表明,使用3种植保无人机喷雾,安装有TEEJET110015#喷头的植保无人机的雾滴沉积密度为24.1～127.4个/cm~2,平均值为75.8个/cm~2,沉积量为0.002～1.15μg/cm~2,均值0.58μg/cm~2;安装有TEEJET11001#喷头的植保无人机的雾滴沉积密度为15.0～80.4个/cm~2,平均值为47.7个/cm~2,沉积量均值为0.01～1.38μg/cm~2,均值0.70μg/cm~2;安装有TEEJET11003#喷头的植保无人机的雾滴沉积密度为9.2～18.2个/cm~2,平均值为13.7个/cm~2;沉积量为0～1.14μg/cm~2,均值0.57μg/cm~2。农药利用率为49.3%～58.2%。使用3种传统器械喷雾,担架式动力喷雾机喷雾得到的沉积量为0.02～0.30μg/cm~2,均值0.16μg/cm~2,背负式手动喷雾器喷雾得到的沉积量为0.01～0.46μg/cm~2,均值0.23μg/cm~2,背负式电动喷雾器喷雾得到的沉积量为0.01～0.65μg/cm~2,均值0.33μg/cm~2。农药利用率为33.7%～39.6%。结果表明,3种植保无人机喷雾的农药沉积量和利用率均高于3种传统的施药器械,但其喷雾的均匀性还有待提高。施药后4 d,植保无人机低空低容量喷雾对茶小绿叶蝉防治效果为85.8%～90.4%,传统大容量喷雾对茶小绿叶蝉防治效果为91.8%～93.2%,两者差异不显著。药后10 d,前者对茶小绿叶蝉防治效果为72.9%～75.6%,后者防治效果为65.8%～71.6%,说明植保无人机低空低容量喷雾对茶小绿叶蝉的防治效果优于传统大容量喷雾。研究结果表明,植保无人机低空低容量喷雾有着更长的持效期,为茶园的农药减施增效提供了可能性。     

农药喷雾试验研究的现状

总结了近年来国内外有关农药精确喷施的主要研究内容及其在农业工程领域中的应用情况,指出了农药精确喷雾的主要特点及影响因素,并提出了对该领域进一步研究的几点建议。     

紫色丘陵区工程建设松散堆积物的侵蚀研究

地方经济的快速发展与“西部大开发”实施中的开发建设项目的水土保持日益重要。紫色丘陵区开发项目的工程侵蚀严重,松散堆积物侵蚀模数为13895~52400t/(km2.a),远高于相应对照草坡的侵蚀强度,其侵蚀产沙量与堆积物的形态与位置、坡度与坡长及植被覆盖度有关,其侵蚀也具有明显的时间特点。松散堆积物侵蚀的控制应选用土生藤本和草本植物。     

Temporal (1958–1993) and spatial patterns of land use changes in Haut-Saint-Laurent (Quebec, Canada) and their relation to landscape physical attributes

In the last few years, landscape researchers have sought to understand temporal and spatial patterns of landscape changes in order to develop comprehensive models of land cover dynamics. To do so, most studies have used similar methods to quantify structural patterns, usually by comparing various landscape structural indices through time. Whereas the necessity for complementary approaches which might provide insights into landscape dynamics at some finer scale relevant to local managers has been expressed, few studies have proposed alternative methodologies. Moreover, the important relationship between the physical constraints of the landscape and land use dynamics has been seldom emphasized. Here we propose a methodological outline which was applied to the study of a rural landscape of Southern Quebec, Canada, to detect spatial and temporal (1958 to 1993) patterns of land cover changes at field, patch and landscape level. We then relate these patterns to the underlying physical structure of landscape elements using GIS and canonical correspondence analyses. We use the different geomorphological deposit types as stable discriminant factors which may constrain land use.Canonical correspondence analyses showed relations of land use and land use changes to the physical attributes of the landscape elements, whereas spatial analyses revealed very dynamic patterns at finer spatial and temporal scales. They highlighted the fact that not only the physical attributes of the landscape elements but also their spatial configuration were important determinants of land use dynamics in this area. Thus more land use changes occurred at the boundary between geomorphological deposit types than in any other locations. This trend is apparent for specific small-size changes (e.g. forest to crop), but not for the large-size ones (e.g. abandoned land to forest). Although land use changes are triggered by socioeconomic forces in this area, these changes are nevertheless constrained by the underlying physical landscape structure. A thorough comprehension of historical changes will enhance our capability to predict future landscape dynamics and devise more effective landscape management strategies.