沙地樟子松天然林长期定位监测样地的最小面积界定

利用在红花尔基沙地樟子松天然林中所设置的2块1 hm2大样地,借助Winkelmass软件设置不同样地大小并随机进行100次重复抽样,统计分析了不同样地大小对林分结构研究中的两个重要因子(林分密度、林木分布格局估计)的影响。结果表明:当调查面积增加到3 600 m2时,林分的密度估计趋于稳定,相对误差不超过10%;林分结构参数角尺度也趋于稳定,格局吻合率达95%以上,由此确定出红花尔基沙地樟子松天然林森林结构研究的最小取样面积为3 600 m2。     

烤烟井窖式移栽下不同密度和留叶数对质体色素及其降解产物含量的影响

为探讨烤烟井窖式移栽下烟株的适宜群体结构,提高烟叶品质,以烤烟品种云烟87为材料,采用田间试验,研究了井窖式移栽下不同密度和留叶数对烤烟质体色素及其降解产物含量的影响。结果表明:烤烟井窖式移栽下,密度、留叶数、密度×留叶数互作对质体色素及其降解产物含量均有显著影响。随密度降低,烤后烟叶叶绿素含量呈"V"形变化趋势,新植二烯、类胡萝卜素及其降解产物含量均呈先增加后降低的趋势;不同留叶数处理比较,叶绿素a、叶绿素b和叶绿素总量均表现为B3(24片/株)B1(18片/株)B2(22片/株),且B2处理叶绿素、类胡萝卜素降解产物含量均最高。不同密度与留叶数互作处理烤后烟叶叶绿素降解产物新植二烯含量和类胡卜素降解产物总量均以A2B2[密度16 675株/hm~2(行株距100 cm×60 cm)+留叶数22片/株]最高,分别为1 095.15μg/g和69.561 7μg/g,占挥发性香气物质总量的89.29%和5.67%。综合分析,井窖式移栽下,密度16 675株/hm~2(行株距100 cm×60 cm)+留叶数22片/株的群体结构有利于提高烟叶品质。     

试析发展性德育的理性归因

道德危机和德育低效的现状使发展性德育理念应运而生.发展性德育的提出不仅具有现实针对性,而且具有深刻的理论依据,主要可以从社会发展、德育实践和德育主体等三个层面进行分析.对发展性德育理论依据的探讨,为印证这一理论体系的科学性和必要性打下了基础,为其内涵拓展、价值溯求和实践体系的构建作了必要的铺垫.     

基于大数据火电厂精准喷氨控制系统

对火电厂脱硝喷氨量过大原因进行了分析,提出了优化解决方案:采取多点取样,使氨气均匀混合,采样更具有代表性;通过大数据分析建立数学模型,对喷氨指令形成预判,达到精准喷氨,从而实现了节约成本、提高脱硝效率的目的.     

Yak Calving Interval and Calving Efficiency

The results of 439 times of calving interval(CI) from 161 yak cows showed that the average CI is 459(se=131)d. The CI with 3 to 6 calving numbers is 25～48 d shorter than that of 1 to 2 and above 7 calving numbers. Although slaughtering a great number of calves during the late September and early October do bring about relatively higher calving rate that is mos yak cowst can give 3,4,5 and 6calves during 4,5,6 and 7 years old respectively. This makes major calving months shift from April or May to June.     

线截抽样中两个样本被同时抽中的概率及其协方差的研究

通过对线截抽样中样本间两两同时出现的概率进行研究，解决树木间的协方差问题，以便通过一条样线对总体作出估计     

四倍体沙01梨F_1代染色体数目鉴定

本文对四倍体沙 0 1梨 F1 代单株进行了染色体数目鉴定 ,共 8个组合 1 0 7株 ,发现4 9株三倍体 2 n=3 x=51 ,其中 1株为大水核×沙 0 1 F1 代 ,2 6株为沙 0 1×大南果梨 F1 代 ,3株为大南果梨×沙 0 1 F1 代 ,1 1株为沙 0 1×秦酥 F1 代 ,2株为安梨×沙 0 1 F1 代 ,6株为沙 0 1×金花 4号 F1 代 ,三倍体出现率为 4 5.8 ;1株为四倍体 2 n=4 x=68 ,系安梨×沙 0 1 F1 代 ,占观察总数的 0 .9 ;1 0株为非整倍体 ,均为三倍体作母本的 F1 代 ,占观察总数的 9.3 .结果表明 ,沙 0 1梨作母本 ,二倍体大南果梨作父本 ,是获得三倍体单株的理想组合 ,沙 0 1是倍性育种的优异种质资源     

Concurrent assessment of fish and habitat in warmwater streams in Wyoming

Abstract  Fisheries research and management in North America have focused largely on sport fishes, but native non-game fishes have attracted increased attention due to their declines. The Warmwater Stream Assessment (WSA) was developed to evaluate simultaneously both fish and habitat in Wyoming streams by a process that includes three major components: (1) stream-reach selection and accumulation of existing information, (2) fish and habitat sampling and (3) summarisation and evaluation of fish and habitat information. Fish are sampled by electric fishing or seining and habitat is measured at reach and channel-unit (i.e. pool, run, riffle, side channel, or backwater) scales. Fish and habitat data are subsequently summarised using a data-matrix approach. Hierarchical decision trees are used to assess critical habitat requirements for each fish species expected or found in the reach. Combined measurements of available habitat and the ecology of individual species contribute to the evaluation of the observed fish assemblage. The WSA incorporates knowledge of the fish assemblage and habitat features to enable inferences of factors likely influencing both the fish assemblage and their habitat. The WSA was developed for warmwater streams in Wyoming, but its philosophy, process and conceptual basis may be applied to environmental assessments in other geographical areas.     

氯前列烯醇对母蓝狐产仔率及胎产仔数影响的初步研究

为探索进一步提高母狐产仔率及胎产仔数的有效途径和方法,在狐的人工授精程序中通过向精液加入不同剂量的PGF2α类似物———氯前列烯醇,比较各组母狐产仔率、胎平均产仔数,以及各组精子在体外的活力变化。结果表明,氯前列烯醇可以提高母蓝狐的产仔率、胎产仔数,改变精子的休眠状态并活化精子,对狐繁殖具有积极作用,在生产中具有一定的应用价值。     

Inter-calibration of three electric fishing techniques to estimate 0+ juvenile fish densities on sandy river beaches

Abstract  The efficiencies of three different techniques for 0+ fish point abundance sampling by electric fishing were tested on a sandy beach of the Morava River, Czech Republic. During direct electric fishing (DE), the operator immerses an anode fastened on an extension pole. During thrown anode electric fishing (TE), the anode is thrown at a distance from the bank. During remote electric fishing (RE), a pre-positioned anode is activated after allowing sufficient time for fish to recolonise the area. The DE technique was found to disturb fish and that fish tend to escape, thereby reducing its efficiency (30% of efficiency of RE). There was no significant difference in relative abundance estimates or size structure of assemblages between DE and RE, but TE seemed to be a species selective technique on sandy river beaches, significantly overestimating relative abundance of bleak. Of the three techniques tested, RE was the most efficient and if time required for deployment could be reduced, it would be also the most suitable for monitoring 0+ fish assemblages on sandy river beaches.