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101.
对鲤鱼、蟾蜍、家鸡、家兔四种动物主要内脏器官进行称量并对脏器系数进行测定,对同类动物不同性别间脏器系数的差异和各脏器系数之间的大小进行了比较。结果表明,鲤鱼、蟾蜍和家兔各脏器质量,雌雄间无明显差异,但家鸡部分脏器质量雌雄间有明显差异。家鸡的脏器系数(肝脏除外),雄性明显高于雌性(P<0.05),鲤鱼和蟾蜍的肾脏系数性别差异显著(P<0.05)。四种动物的心脏系数:家鸡>蟾蜍>家兔>鲤鱼;肝脏系数:家兔>蟾蜍>家鸡;肺脏系数:蟾蜍>家鸡>家兔;脾脏系数:鲤鱼>家鸡>家兔>蟾蜍;肾脏系数:家鸡>家兔>蟾蜍>鲤鱼。由此可见,动物的脏器系数的大小与其进化水平有一定的相关性。 相似文献
102.
分类表决制度是我国证券市场的一大制度革新。随着我国股权分置改革的全面推进,分类表决制度也发挥着越来越重要的作用,它赋予流通股股东更多自我保护的权益,对股权分置改革起到有力的推动作用;同时,它也存在着不容忽视的局限性。文中通过具体分析,提出一些建议以供参考。 相似文献
103.
The relationship between the physicochemical properties (molar volume, partition coefficient, and dissociation constant) of slow-acting systemic postemergence xenobiotics and their uptake and translocation to the sites of action was investigated using the nonlinear, dynamic simulation model ERMESSE. When the pKa was held constant at 4.0, the model enables the prediction of the uptake of a systemic xenobiotic as a function of its partition coefficient and molar volume. The model also considered the effects of the physicochemical properties of a systemic xenobiotic on its long-distance translocation within the vascular tissues. For instance, when the log Kow and pKa were held constant at 1.5 and 6.0, respectively, the model predicted a higher translocation rate (55%) for molecules with a small (e.g., MV = 100 cm3 mol−1) as opposed to a large (e.g., MV = 300 cm3 mol−1, 33%) molar volume. In addition, the theoretical predictions from the ERMESSE model showed that any xenobiotic with a molar volume not exceeding 300 cm3 mol−1 could provide an uptake ?50% and a translocation rate ?25% when its log Kow is between −0.5 and 2.5 and its pKa is between 0.0 and 8.0. 相似文献
104.
SHEN Hong CHEN Mingjie ZHAO Yongchang PAN Yingjie Key Laboratory of Agricultural Genetics Breeding of Shanghai 《食用菌学报》2007,(2)
Fourteen Morchella samples (eleven from Yunnan and three from Zhejiang Provinces) were selected on the basis of differences in fruit body morphology. Ribosomal DNA internal transcribed spacers (ITS) were amplified in each case using the universal primer pair, ITS-1 and ITS-4, and the amplification products were purified and sequenced. Comparisons with sequence data in GenBank revealed that the 11 Morchella isolates collected from Yunnan belonged to four species: Morchella elata, Morchella conica, Morchella crassipes and Morchella costata. The three isolates collected from Zhejiang Province (M12, M13 and M14) were designated as unknown Morchella species. When Verpa conica (AJ544206) (from the genus Verpa belonging to the same family as Morchella) was taken as the outgroup, the 14 isolates formed three groups, M. elata, M. costata (Group 1); Morchella esculenta, M. conica (Group 2); and M. crassipes, M12, M13 and M14 (Group 3). 相似文献
105.
微孔草的分布及植物群落特征研究 总被引:5,自引:0,他引:5
采用定量样地法,对孔微草这一特种油料植物的群落结构、群落变异以及群落特征进行了研究。结果表明,微孔草干物质生产量占总量的比率,休闲地为9.16%、撩荒地为16.90%、油草地为15.32%、燕麦地为10.66%、青稞地为5.97%;群落系数相应为87.09%、87.91%、91.82%、95.65%、93.60%;优势度相应为9.60%、13.45%、11.99%、16.61%、7.13%。经主分 相似文献
106.
107.
《Scandinavian Journal of Forest Research》2012,27(4):373-385
Abstract Methods for small area estimations were compared for estimating the proportion of forest and growing stock volume of temperate mixed forests within a district of a member state (canton) in Switzerland. The estimators combine terrestrial data with remotely sensed auxiliary data. By using different model types, different sources of auxiliary data and different methods of processing the auxiliary data, the increase in estimation precision was tested. Using the canopy height derived from remote sensing data, the growing stock volume and the proportion of forest were estimated. The regression models used for the small area estimation provided a coefficient of determination of up to 68% for the timber volume. The proportion of plots correctly classified into forest and non-forest plots ranged between 0.9 and 0.98. Models calibrated over forest area only resulted in a maximal coefficient of determination of 37%. Even though these coefficients indicate a moderate model quality, the use of remote sensing data clearly improved the estimation precision of both the proportion of forest and the growing stock volume. Generally, Lidar data led to slightly higher estimates compared to data from aerial photography. It was possible to reduce the variance of the estimated proportion of forest to nearly one tenth compared with the variance based on the terrestrial measurements alone. Similarly, the variance of the growing stock volume could be reduced to one fourth as compared with the variance based solely on the terrestrial measurements. 相似文献
108.
本文介绍了用成套小样园作为典型众数抽样调查单元的方法测定两个不同林分小班的蓄积,并与用点抽样和不同形状样地的系统抽样结果相比较,表明用成套小样园作为典型众数抽样调查单元的方法能满足90%以上的精度,而且工效很高;作者也探讨了使用此法的条件. 相似文献
109.
孙枫林 《湖南农业大学学报(自然科学版)》2000,27(2)
人才,是经济社会活动诸多要素中最主要,最活跃的要求,结构合理的人才队伍才有可能产生高的效率和效益。本文应用灰关联度分析方法,以通信产业人才队伍为例进行分析,为制定合理的人才队伍结构提供了一种评价方法。 相似文献
110.
为了分析玻璃退火过程中永久应力的形成规律以及应力值的大小,基于玻璃永久应力的成因分析,建立了弹性体数值模型,给出了永久应力的计算方法和步骤。根据所建模型,利用ansys软件模拟了玻璃退火过程中结构应力和残余温差应力的形成过程,发现结构应力产生于膨胀系数开始发生变化的温度567℃,停止于膨胀系数稳定时的温度480℃。并根据模拟结果,计算出了玻璃中永久应力值的大小:边部压应力1.022MPa,中部张应力0.602MPa。模拟过程比较准确地反应了实际玻璃退火过程中应力的形成过程,根据模拟值求出的应力值大小基本符合玻璃实际应力值情况。 相似文献