云南杂毛虫生物学特性和林间消长规律     

彭石灵  童国健 《广东林业科技》2000,16(3):28-31

云南杂毛虫是红锥的主要害虫,为广东新发现虫种,其生物学特性国内尚未报导。该虫每年发生１代,１１月下旬以卵在树皮内越冬,２月中旬幼虫孵化,９月中旬结茧,１１月下旬羽化。幼虫７龄,昼伏夜出,林间卵和低龄幼虫生存率低,老熟林和林缘木易受害。  相似文献   

RTK联合全站仪在南川石漠化地区测图中的应用分析     

孙锋  谢世友  曹振科 《西南大学学报(自然科学版)》2011,33(8)

以南川石漠化山区地形测图为例,对实时载波相位差分技术(RTK)联合全站仪进行数字化测图的作业流程、控制点精度进行分析,指出RTK与全站仪的有效结合,不但可以提高速度、节约时间、节约人力、财力,而且可以保证测图的精度.  相似文献   

12个薄壳山核桃无性系果(核)性状以及产量的比较   总被引：2，自引：0，他引：2  

李川  姚小华  王开良  方敏瑜  辜夕容  邵慰忠 《西南大学学报(自然科学版)》2011,33(6)

分别比较了12个薄壳山核桃无性系果实、核果以及产量之间的差异,分析了各无性系果实性状、核果性状以及产量等12个指标之间的相关性.结果表明:薄壳山核桃果实性状、核果性状以及产量等12个指标在各无性系间均存在极显著的差异;12个无性系果实性状总体变异系数从大到小顺序依次为:单株鲜果产量(变异系数CV为61.06%),果质量(30.18%),果皮厚(25.60%),果高(16.48%),果型指数(13.77%),果径(10.54%),这与12个无性系核果性状总体变异系数的大小顺序(单株核果产量,核质量,出核率,核高,核型指数,核径)是一致的;不同无性系果质量与核质量(果径与核径)、果高与核高(果型指数与核型指数)分别呈显著、极显著正相关,因而可以根据薄壳山核桃果实的外形及大小来初步判断核果的形状和大小.  相似文献   

RELEVANCE OF A RAPID APPRAISAL APPROACH TO IDENTIFY LOCALLY AVAILABLE FEED INGREDIENTS TO SMALL-SCALE NILE TILAPIA (Oreochromis niloticus L.) AQUACULTURE     

M. A. Kabir Chowdhury  Dominique P. Bureau  Manik L. Bose  Madan Dey 《Aquaculture Economics & Management (Blackwell Science)》2013,17(2):151-169

Applications of a rapid appraisal approach to identify locally available feed ingredients in feed formulation, production, and socio-economics of Nile tilapia aquaculture in Bangladesh are discussed. Three diets of 35%, 30%, and 25% crude protein were formulated using locally available ingredients, and their essential amino acid profiles were assessed for Nile tilapia. Six production scenarios were constructed using these diets and two culture periods of 100 and 150 days were considered. The production scenarios with 35% protein yielded the highest productivity and profitability over the 150-day culture period followed by the 30% protein scenario. Identification of locally available ingredients and their application in small-scale Nile tilapia aquaculture may lead to: (1) increased availability of inexpensive sources of fish production for poor people; (2) increased fish consumption; (3) increased self employment and involvement of women in productive activities; and (4) increased household income to reduce poverty.  相似文献   

兔粘液瘤病诊断方法的研究     

张敬友  张常印 《中国兽药杂志》1998,32(3):6-9

注射过粘液瘤病毒的兔子全部死亡，主要病变为皮下发生粘液性肿胀，和真皮中有星形、梭形或蝌蚪形瘤细胞浸润，在表皮的基细胞和棘细胞层中及瘤细胞中存在有不同阶段的病毒粒子和病毒包涵体，建立了琼脂扩散检测法用于粘液瘤病的诊断。  相似文献