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841.
People receive information about visiting places from a variety of sources, and it is important to understand how information
affects recreation experiences. This study examines how different information treatments describing a recreation place influence
perceived crowding and encounter norms. The study location was the Jungmoeri area of Mudeungsan Provincial Park (MPP) in Korea.
Data were collected from 50 college students utilizing a series of simulated moving pictures in a laboratory setting. Respondents
were given information describing three different types of conditions and experiences (nature preserve, transition/buffer,
and developed area), plus a no information control. Results showed that information influenced perceived crowding and encounter
norms. For the range of encounter numbers depicted in the photos, the nature preserve treatment produced higher crowding ratings
and lower tolerances for encounters, the developed area treatment produced lower crowding ratings and higher tolerances, and
the transition/buffer and the control were in between. Information treatments also influence the perceived importance of encounter
numbers, and importance was highest for the nature preserve. Management implications are discussed. 相似文献
842.
843.
844.
在企业中非正式群体是客观存在的,它对企业安全管理具有正向(积极)和负向(消极)的双重功能。如果正确引导,非正式群体可弥补正式群体的不足,在实现企业安全生产目标中发挥重要的作用,反之,则会干扰企业安全生产目标的实现。企业安全管理者应正视非正式群体的存在,并正确认识非正式群体,充分利用其特点,加强引导与控制,因势利导,趋利避害,调动一切积极因素,为实现企业安全目标服务。本文介绍了企业非正式群体的类型及特点,阐述了在企业安全管理中如何加强对非正式群体的引导、利用及控制管理,充分发挥非正式群体的正向功能,限制其负向功能。 相似文献
845.
Sun Hwa Hong Sun Ah Choi Myung-Hyun Lee Bo Ra Min Cheolho Yoon Hyeon Yoon Kyung-Suk Cho 《Environmental geochemistry and health》2011,33(1):41-47
The effects of arsenic (As) species, such as As(III), As(V) and dimethylarsinic acid (DMA), on the accumulation of As in cucumber (Cucumis sativus), as well as on its growth in a soil mesocosm were evaluated. When Cucumis sativus was cultivated in soils contaminated with 20 and 50 mg/kg of As(III), As(V) or DMA for 40 days, the growth was markedly inhibited by the inorganic As (As(III) and As(V)) rather than the organic As (DMA). Irrespective of the As species, the As concentrations accumulated in Cucumis sativus increased with increasing As concentration in the soil. The As bioaccumulation factors from soil into the tissue of Cucumis sativus were 17.5–35.4, 29.3–42.7 and 17.6–25.7 for As(III), As(V) and DMA, respectively. In addition, the As translocation factors from the roots to shoots were 0.025–0.031, 0.018–0.032 and 0.014–0.026 for As(III), As(V) and DMA, respectively. In conclusion, Cucumis sativus mainly accumulated As in its roots rather than its shoots and easily accumulated inorganic rather than organic As from the soil into its tissue. 相似文献
846.
Hong SH Choi SA Lee MH Min BR Yoon C Yoon H Cho KS 《Environmental geochemistry and health》2011,33(Z1):41-47
The effects of arsenic (As) species, such as As(III), As(V) and dimethylarsinic acid (DMA), on the accumulation of As in cucumber (Cucumis sativus), as well as on its growth in a soil mesocosm were evaluated. When Cucumis sativus was cultivated in soils contaminated with 20 and 50 mg/kg of As(III), As(V) or DMA for 40 days, the growth was markedly inhibited by the inorganic As (As(III) and As(V)) rather than the organic As (DMA). Irrespective of the As species, the As concentrations accumulated in Cucumis sativus increased with increasing As concentration in the soil. The As bioaccumulation factors from soil into the tissue of Cucumis sativus were 17.5-35.4, 29.3-42.7 and 17.6-25.7 for As(III), As(V) and DMA, respectively. In addition, the As translocation factors from the roots to shoots were 0.025-0.031, 0.018-0.032 and 0.014-0.026 for As(III), As(V) and DMA, respectively. In conclusion, Cucumis sativus mainly accumulated As in its roots rather than its shoots and easily accumulated inorganic rather than organic As from the soil into its tissue. 相似文献
847.
Surface modelling of global terrestrial ecosystems under three climate change scenarios 总被引:7,自引:0,他引:7
Tian-Xiang Yue Ze-Meng FanChuan-Fa Chen Xiao-Fang SunBai-Lian Li 《Ecological modelling》2011,222(14):2342-2361
A high accuracy and speed method (HASM) of surface modelling is developed to find a solution for error problem and to improve computation speed. A digital elevation model (DEM) is established on spatial resolution of 13.5 km × 13.5 km. Regression formulations among temperature, elevation and latitude are simulated in terms of data from 2766 weather observation stations scattered over the world by using the 13.5 km × 13.5 km DEM as auxiliary data. Three climate scenarios of HadCM3 are refined from spatial resolution of 405 km × 270 km to 13.5 km × 13.5 km in terms of the regression formulations. HASM is employed to simulate surfaces of mean annual bio-temperature, mean annual precipitation and potential evapotranspiration ratio during the periods from 1961 to 1990 (T1), from 2010 to 2039 (T2), from 2040 to 2069 (T3), and from 2070 to 2099 (T4) on spatial resolution of 13.5 km × 13.5 km. Three scenarios of terrestrial ecosystems on global level are finally developed on the basis of the simulated climate surfaces. The scenarios show that all polar/nival, subpolar/alpine and cold ecosystem types would continuously shrink and all tropical types, except tropical rain forest in scenario A1Fi, would expand because of the climate warming. Especially at least 80% of moist tundra and 22% of nival area might disappear in period T4 comparing with the ones in the period T1. Tropical thorn woodland might increase by more than 97%. Subpolar/alpine moist tundra would be the most sensitive ecosystem type because its area would have the rapidest decreasing rate and its mean center would shift the longest distance towards west. Subpolar/alpine moist tundra might be able to serve as an indicator of climatic change. In general, climate change would lead to a continuous reduction of ecological diversity. 相似文献
848.
国际生态学研究发展态势文献计量分析 总被引:5,自引:0,他引:5
目前,全球的生态环境问题已经引起了各国政府和人民的高度关注,而生态学研究可以为人类与自然生态系统的共存提供理论依据和行动指南。利用Thomson Data Analyzer、NetDraw和Aureka等分析工具,结合Pathfinder算法,对SCIE和SSCI数据库中国际生态学研究相关文献进行统计分析,发现:北美、欧洲、澳大利亚等国及其研究机构在生态学领域的论文影响力较大,论文质量较高;美国是全球生态学研究合作网络的中心,其次是英国和德国;在机构层面上,加州大学戴维斯分校和马普学会是两个比较明显的合作中心;我国在生态学研究领域发文量上具有一定的优势,但论文总体质量仍有待继续提高,目前我国在生态学领域的主要合作国家有美国、英国、加拿大、德国、日本、澳大利亚和法国;2008—2010年国际生态学研究热点主要集中在生物多样性、气候变化、基因变异、物种间相互作用和性选择等研究领域。 相似文献
849.
Assessment of spatial distribution of soil loss over the upper basin of Miyun reservoir in China based on RS and GIS techniques 总被引:2,自引:0,他引:2
Chen T Niu RQ Wang Y Li PX Zhang LP Du B 《Environmental monitoring and assessment》2011,179(1-4):605-617
Soil conservation planning often requires estimates of the spatial distribution of soil erosion at a catchment or regional scale. This paper applied the Revised Universal Soil Loss Equation (RUSLE) to investigate the spatial distribution of annual soil loss over the upper basin of Miyun reservoir in China. Among the soil erosion factors, which are rainfall erosivity (R), soil erodibility (K), slope length (L), slope steepness (S), vegetation cover (C), and support practice factor (P), the vegetative cover or C factor, which represents the effects of vegetation canopy and ground covers in reducing soil loss, has been one of the most difficult to estimate over broad geographic areas. In this paper, the C factor was estimated based on back propagation neural network and the results were compared with the values measured in the field. The correlation coefficient (r) obtained was 0.929. Then the C factor and the other factors were used as the input to RUSLE model. By integrating the six factor maps in geographical information system (GIS) through pixel-based computing, the spatial distribution of soil loss over the upper basin of Miyun reservoir was obtained. The results showed that the annual average soil loss for the upper basin of Miyun reservoir was 9.86 t ha(-1) ya(-1) in 2005, and the area of 46.61 km(2) (0.3%) experiences extremely severe erosion risk, which needs suitable conservation measures to be adopted on a priority basis. The spatial distribution of erosion risk classes was 66.9% very low, 21.89% low, 6.18% moderate, 2.89% severe, and 1.84% very severe. Thus, by using RUSLE in a GIS environment, the spatial distribution of water erosion can be obtained and the regions which susceptible to water erosion and need immediate soil conservation planning and application over the upper watershed of Miyun reservoir in China can be identified. 相似文献
850.
为提高职业健康安全管理体系(OHSMS)绩效和职业健康安全绩效,根据OHSMS绩效评价的重要性,提出基于二元语义的OHSMS绩效评价模型。研究科学合理的评价指标体系,并运用层次分析法(AHP)和灰色关联分析法(GRA)确定主客观权重,再运用乘法集成法确定组合权重,作为评价指标的最终权重,运用二元语义的集结算子,计算OHSMS绩效评价指标的综合值,取得最终的评价结果。结果表明,基于二元语义的OHSMS绩效评价将专家经验与定量计算相结合,合理地处理许多因素的不确定性,通过确定不符合项和改进措施,持续改进OHSMS绩效。 相似文献