基于本科生科研能力培养的普通昆虫学课程教学改革探讨     

王厚帅 《现代农业科技》2019,(10)

本文从本科生科研能力培养的角度探讨了普通昆虫学理论课、实验课、实习课及考核方式的教学改革,以期促进创新型植物保护人才的培育。  相似文献   

营业税改征增值税的税率评估——基于可计算一般均衡模型的研究     

李学林 《湖南农业大学学报(自然科学版)》2013,(5):80-84

营业税改征增值税是完善我国税制的一个重要举措，确定各个产业部门改征增值税后的税率是其中一个关键的环节。运用可计算一般均衡模型可以评估营业税改征增值税之后不同税率的选择对宏观经济和产业结构的影响。政策模拟的结果显示，目前正在实施的营业税改征增值税的试点方案权衡了对财政收入和经济增长以及经济结构的影响，是对经济运行影响较小的稳健选择。  相似文献   

The Economic Significance of Hunting Tourism in East Lapland,Finland     

Anne Matilainen  Susanna Keskinarkaus  Hannu Törmä 《Human Dimensions of Wildlife》2016,21(3):203-222

Uses of game resources are under constant debate. One such debate focuses on hunting tourism and its contributions to rural economics. To prioritize future investment and inform policy decisions, it is necessary to identify the full economic consequences of the operation of hunting tourism companies in rural areas. However, the true economic significance of these typically small-scale companies is not apparent when examined on an industrial scale. These companies may nevertheless serve as a sustainable solution to local-scale rural challenges. In this article, the regional economic significance of hunting tourism is estimated for the East Lapland sub-region of northern Finland through the use of Computable General Equilibrium simulation models. Although these models are known to effectively evaluate short- and long-term regional economic effects of industries such as tourism, they have not previously been applied to evaluate hunting tourism.  相似文献   

玉米人工合成群体产量相关性状选择潜势及杂种优势模式分析   总被引：5，自引：2，他引：5  

铁双贵  卢彩霞  丁勇  郑用链 《华北农学报》2002,17(1):30-34

采用NCⅡ遗传交配设计 ,以分属于不同杂种优势群的 6个自交系做测验种 ,与 6个合成群体组配成 36个组合。结果表明 :单株产量的GCA以LBM最高 ,其次为WBM ,从株型、穗型性状的SCA分析合成群体与自交系组成了 9个优良杂种优势模式。单株产量最高的组合为HZ85×WBM ,其均值为 10 8 75g。通过对优良杂优模式内的变异参数估计 ,在群体内有丰富的变异个体 ,具有很强的选择潜势。组合内个体产量分布以及出现的频率对选系和轮回选择具有明确的指导意义。人工合成群体具有丰富的遗传变异 ,分属于不同的杂种优势类群 ,具有多元种质的特性。作为选系和轮回选择群体 ,具有明显的选择潜势  相似文献   

应用GCMs和历史气候资料生成我国在CO2倍增时的气候情景   总被引：21，自引：2，他引：19  

金之庆  陈华 《中国农业气象》1992,13(5):13-21

采用3种大气环流模型(GCMs)的输出结果,并结合我国各地有代表性气象台站20-30年的逐日气象资料,在微机上生成了我国在CO_2倍增时的3种气候情景.进而分析了我国未来温度、降水和太阳辐射3要素可能的时空分布特征和季节变化趋势,并推测我国易受全球气候变化不利影响的脆弱地区.  相似文献   

四川洪雅丘陵草地植物群落经济性状与综合特征研究     

饶开晴  徐亚欧  王晋峰 《草业与畜牧》2006,(11):6-9,20

论述了洪雅丘陵疏林草丛草地与农隙草丛草地两种草地类型中6个群落的植物性生产能力及相关的多项生态经济性状、种群优势度（SDR）、重要值（Ⅳ）；比较了两种草地类型各群落间SDR、Ⅳ及植物产量、经济类群组成、各项指标的差异性、共同性。说明自然因素（特别是气候）及人为因素（放牧、刈割、烧草）对草地植被组成及产量的影响。  相似文献   

毕节地区林业有害生物普查     

刘正忠  郑红军  曾宪勤  万艳  吴军 《贵州林业科技》2007,35(3):57-64

对全区林业有害生物进行普查,初步查出林业有害生物共七大类147种,病害53种,虫害83种,鼠(兔)害8种,寄生性种子植物3种,蜱螨3种,软体动物2种,有害植物1种.发现林业外来有害生物松材线虫病1种,有害植物紫茎泽兰1种,本土有害生物145种.  相似文献   

Catch per unit effort standardization of the eastern Bering Sea walleye pollock (Theragra chalcogramma) fleet     

Brian C. Battaile  Terrance J. Quinn II   《Fisheries Research》2004,70(2-3):161-177

A general linear model (GLM) was used to standardize catch per unit effort (CPUE) data for Alaska walleye pollock (Theragra chalcogramma) from the Bering Sea fleet for the years 1995–1999. Data were stratified temporally by year and season and spatially by area using either Alaska Department of Fish and Game (ADF&G) or National Marine Fisheries Service (NMFS) reporting areas. Four factors were used: vessel identification (ID) number, vessel speed, percentage of pollock by weight in the haul (a measure of targeting), and whether most of the haul took place before or after sunset. At least 29 combinations of main effects, quadratic covariates, and interactions were tested for each year/area/season stratum. GLM models explained from 31 to 48% of the total sums of squares. Vessel identification number was included in all models and explained the most variability. Of the remaining factors, the square of the percentage of pollock in the haul was included in most models, following an F-test to determine parsimony. Analysis of the vessel identification number coefficients indicated that larger vessels tended to have higher CPUEs; and that this relationship differed between dedicated catcher vessels and offshore catcher processors. Coefficient estimates and response surfaces generally indicated increased CPUEs with the percentage of pollock in the haul and showed mixed results with vessel speed. The vessel identification number incorporated most vessel characteristics, leaving vessel speed primarily as a fitting variable with less biological meaning. The year/area/season stratification procedure was found to be necessary due to the unbalanced design, which otherwise would have factor levels with no data in a large combined model. In addition, the stratification procedure reduced the variability in CPUE substantially.  相似文献   

浅析我国种子产业发展概况     

肖艳云  东丽  谢辉  于洪兰  李志彬  刘欣  关峰  蔡卓  曲丽君  于雨生  刘晓娟 《杂粮作物》2014,(8)

该文将从种子产业的规模、行业集中度、科研现状、产品结构和经营模式、推广和流通服务等方面对我国种子产业发展概况进行分析,旨在为种子产业发展提供借鉴。  相似文献   

土地利用总体规划实施监测评估研究——以邵阳市城区为例     

张伟娜申瑞瑞  张伟伟 《安徽农业科学》2014,(20):6809-6812

中心城区的土地利用监测是土地利用规划实施评估的重点内容,是土地利用规划顺利实施的重要保障之一。该研究以邵阳市城区为例,以2006~2012年邵阳市土地利用变更调查数据图件以及历年建设用地管理台账、农用地转用台账、土地开发整理台账等国土资源局相关科室统计资料为基础,对邵阳市2009~2012年土地利用变更调查图和土地利用规划图进行叠加分析并提取土地利用变化的图斑,从而对其扩张的规模和布局进行空间偏离度分析和评估。在此基础上,对邵阳城区用地需求进行分析,并提出规划调整应采取的方式:邵阳市在用地布局上应尽量与城市总体规划相衔接,优化中心城区工业用地布局,参考已确定的招商引资项目情况,将近期急需落地但又不在规划圈内的项目用地调整到规划圈内。  相似文献