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131.
区域资源禀赋对资源利用效率影响研究 总被引:5,自引:0,他引:5
论文将研究的视点从关注资源禀赋与经济发展的关系,转向资源禀赋对资源利用效率的影响上,选取了中国大陆31个省(自治区、直辖市,未计算香港、澳门地区)2008年能源和水资源的面板数据,力图用统计模型来验证资源禀赋对资源利用效率存在负相关作用的假说,即资源越丰富的地区,对该种资源使用效率往往越低。研究发现:资源禀赋对资源利用效率存在显著的逆向影响,资源的"诅咒"效应不仅作用于区域经济发展上,也同样作用于资源利用效率上;然而,不同于经济诅咒,资源禀赋与资源利用效率之间的这种负相关关系在分散型资源上体现更加明显。对区域资源禀赋与资源利用效率之间影响关系与作用机制更深入的研究将为科学、高效的资源管理政策提供理论支持。 相似文献
132.
通过对地壳、海洋及人体中16种元素丰度的分析,得出了环境友好型生产工艺的3个特征,即:整体偏碱性、氧硫比接近2000:1、避免使用低丰度元素。此外还结合上述特征对加压氧化-氰化法和次氯酸钠一步浸金工艺的环境友好性进行了分析。 相似文献
133.
Spatial distribution of archaeal and bacterial ammonia oxidizers in the littoral buffer zone of a nitrogen-rich lake 总被引:3,自引:0,他引:3
Yu Wang Guibing Zhu Lei Ye Xiaojuan Feng Huub J. M. Op den Camp Chengqing Yin 《环境科学学报(英文版)》2012,24(5):790-799
The spatial distribution and diversity of archaeal and bacterial ammonia oxidizers (AOA and AOB) were evaluated targeting amoA genes in the gradient of a littoral buffer zone which has been identified as a hot spot for N cycling. Here we found high spatial heterogeneity in the nitrification rate and abundance of ammonia oxidizers in the five sampling sites. The bacterial amoA gene was numerically dominant in most of the surface soil but decreased dramatically in deep layers. Higher nitrification potentials were detected in two sites near the land/water interface at 4.4-6.1 μg NO2--N/(g dry weight soil·hr), while only 1.0-1.7 μg NO2--N/(g dry weight soil·hr) was measured at other sites. The potential nitrification rates were proportional to the amoA gene abundance for AOB, but with no significant correlation with AOA. The NH4 + concentration was the most determinative parameter for the abundance of AOB and potential nitrification rates in this study. Higher richness in the surface layer was found in the analysis of biodiversity. Phylogenetic analysis revealed that most of the bacterial amoA sequences in surface soil were affiliated with the genus of Nitrosopira while the archaeal sequences were almost equally affiliated with Candidatus ‘Nitrososphaera gargensis’ and Candidatus ‘Nitrosocaldus yellowstonii’. The spatial distribution of AOA and AOB indicated that bacteria may play a more important role in nitrification in the littoral buffer zone of a N-rich lake. 相似文献
134.
135.
Rudolf Izsák 《Environmental and Ecological Statistics》2008,15(2):143-156
In this paper some properties and analytic expressions regarding the Poisson lognormal distribution such as moments, maximum
likelihood function and related derivatives are discussed. The author provides a sharp approximation of the integrals related
to the Poisson lognormal probabilities and analyzes the choice of the initial values in the fitting procedure. Based on these
he describes a new procedure for carrying out the maximum likelihood fitting of the truncated Poisson lognormal distribution.
The method and results are illustrated on real data. The computer program for calculations is freely available.
相似文献
Rudolf IzsákEmail: |
136.
为了探明某矿20910工作面顶板0~100 m上高部区域岩层富水性分布情况,基于音频电透视法,通过在工作面回风巷、运输巷布置了59个发射点,104个接收点,获得了工作面顶板0~50 m、50~100 m高度范围音频电透视成果图。探测结果表明,20910工作面顶板0~100 m存在4处低阻异常区域,实际回采揭露发现涌水点5处,均位于探测低阻异常区域,探测结果与实际揭露结果验证很吻合。实践表明,该矿20910工作面顶板0~100 m音频电透视法探测成果合理可靠,音频电透视法可以准确探测出工作面顶板一定范围内相对富水区域分布情况。 相似文献
137.
东海浮游多毛类的时空分布 总被引:3,自引:0,他引:3
根据1997~2000年东海23°30′~33°00′N、118°30′~128°00′E海域4个季节海洋调查资料,探讨了东海浮游多毛类数量变化、相应的动力学过程及与渔场的关系。结果表明:浮游多毛类秋季平均丰度为23.68×10-2/m3,夏季8.59×10-2/m3,冬季5.80×10-2/m3,春季最低(1.20×10-2/m3);温度在多毛类丰度的季节变化中起主要作用,盐度次之。除了秋季,其他季节多毛类丰度平面分布较为均匀。多毛类的数量波动,与东海暖流势力消长和沿岸水有密切的联系,也同暖流势力从夏季到秋季维持一段时间有密切关系。 相似文献
138.
139.
ROBERT N. LEHMAN KAREN STEENHOF MICHAEL N. KOCHERT LESLIE B. CARPENTER 《Environmental management》1999,23(3):409-417
Buteo regalis ), northern harriers (Circus cyaneus), burrowing owls (Athene cunicularia), and short-eared owls (Asio flammeus) inside and outside a military training site in the Snake River Birds of Prey National Conservation Area, southwestern Idaho.
The Orchard Training Area is used primarily for armored vehicle training and artillery firing by the Idaho Army National Guard.
Relative abundance of nesting pairs inside and outside the training site was not significantly different from 1991 to 1993
but was significantly higher on the training site in 1994 (P ≤ 0.03). Nesting success varied among years but was not significantly different inside and outside the training site (P > 0.26). In 1994, short-eared owl and burrowing owl nests were significantly closer to firing ranges used early in the spring
before owls laid eggs than were random points (P < 0.001). In 1993, distances from occupied burrowing owl nests to firing ranges used early in the year were similar to those
from random points to the same firing ranges (P = 0.16). Military activity contributed to some nesting failures from 1992 to 1994, but some pairs nested successfully near
military activity. 相似文献
140.
This study illustrates the use of modern statistical procedures for better wildlife management by addressing three key issues: determination of abundance, modeling of animal distributions and variability of diversity in space and time. Prior information in Markov Chain Monte Carlo (MCMC) methods is used to improve estimates of abundance. Measures of autocorrelation are included when modeling distributions of animal counts, and a diversity index to indicate species abundance and richness for large herbivores is developed. Data from the Masai Mara ecosystem in Kenya are used to develop and demonstrate these procedures. The new abundance estimates are up to 35% more accurate than those obtained by existing methods. Significant temporal changes in spatial patterns are found from a space-time analysis of elephant counts over a 20-year period, with strong interactions over 5 km and 6 months space and time separations, respectively. The new diversity index is sensitive to both high abundance and species richness and is also able to capture year to year variation. It indicates an overall marginal decrease in diversity for large herbivores in the Mara ecosystem. The space-time analyses and diversity index can easily be computed thereby providing tools for rapid decision making. 相似文献