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171.
Ecosystem functions can be understood as the quantified amount of an ecosystem’s role in a natural process, while ecosystem services are the requantification of the ecosystem functions by factoring in environmental conditions and human needs based on social perspectives. In this study, differences between ecosystem functions and services were presented in terms of air purification of a forest ecosystem. Forest volume growth was employed to quantify the pollutant absorption capacity of a forest and was indicated by the natural functions (NF) for air purification by a forest ecosystem. Forest ecosystem services can be requantified from the forest functions by adding the air pollutant and population densities. Air pollutant density was applied to the assessment of the environmental services (ES) of forest ecosystems. Furthermore, the environmental social services (ESS) of forest ecosystems were assessed by including population density considerations. We simulated differences in NF, ES, and ESS in relation to pollutant and population density; while NF was spatially quantified without a close relationship to air pollutant and population density, ES and ESS reacted to environmental and social condition more sensitively. These results imply that the ecosystem services of forest resources for air purification are high where the pollutant and population densities are high, while the ecosystem functions of forest resources for air purification depend solely on forest conditions and not on the density changes of air pollutants and population. This study suggests that the differences in NF, ES, and ESS are important factors to be understood and considered in the decision-making process for ecosystem services. When considering human needs and surrounding environmental conditions, the results suggest that decision makers should utilize the ES and ESS concepts, which reflect both population and pollutant density along with additional human-related factors. 相似文献
172.
空间功能识别是确定国土空间规划空间开发保护格局的关键环节,理论和实践意义重大。基于土地利用和地表覆盖现状、精细化DEM、地形单元等基础地理信息,水、生态、环境、灾害等专题数据,社会统计数据等多元信息,利用空间分析、多元统计、计量模型、基于规则的分类模型等技术方法,从多元信息综合集成和自动分类识别的角度,研究构建了一套市县国土空间规划空间主导功能识别的关键技术与方法,并对榆林市域进行空间功能分区。研究表明:本文方法有效将地理实体单元、功能评价指标综合于统一的地域单元,保证了空间功能分类识别的准确性;通过自动分类算法建模,实现空间功能识别的自动化,提高了国土空间规划的客观性和工作效率。 相似文献
173.
174.
Qinhua Fang Luoping Zhang Huasheng Hong Liyu Zhang Frances Bristow 《Environment, Development and Sustainability》2008,10(1):41-49
Environmental planning at different levels has been called for by environmental departments in China during last years to
integrate environment consideration to economic development. Based on the accomplished environmental planning practice in
Xiamen China, the paper suggests a general environmental planning process with ecological function zoning as its key steps,
at the same time an effective method for ecological function zoning was formulated. The case studies of Dongfu suburban town
environmental planning and Xiamen eco-city conceptual planning indicate that scientifically sound results of ecological function
zoning can contribute to improving not only the adaptability and acceptability of environmental planning, also the environmental
management and the decision-making. The experience shows that the ecological function zoning methods should be applied according
to the principles of adaptive management, resource-based and community-based, so that it can integrate science into decision-making
process, avoiding both narrow-minded viewpoints of planners and natural resource use conflicts among variety of stakeholders.
Problems to be resolved in the future are also pointed out in the ending part. 相似文献
175.
《Journal of Manufacturing Processes》2014,16(1):86-92
The paper reviews the principles, benefits and limitations of the conventional short circuit transfer mode in GMA welding before describing the development and benefits of the controlled short circuit approach. Various options are described and an attempt is made to categorize the current commercial systems. 相似文献
176.
Susanne P. A. den Boer Jacobus J. Boomsma Boris Baer 《Behavioral ecology and sociobiology》2008,62(12):1843-1849
The seminal fluid that accompanies sperm in ejaculates has been shown or suggested to affect sperm competition and paternity
success of insects by preventing female remating, inducing oviposition, and forming mating plugs. In Atta leafcutter ants, queens have multiple mates but never remate later in life, although they may live and produce fertilized
eggs for several decades. The mating biology and life history of these ants therefore suggests that the major function of
seminal fluid is to maximize sperm viability during copulation, sperm transfer, and initial sperm storage. We tested this
hypothesis by comparing the viability of testis sperm and ejaculated sperm (mixed with seminal fluid) and found a significant
positive effect of seminal fluid on sperm viability. We further quantified this positive effect by adding accessory gland
secretion (a major component of seminal fluid) in a dilution series, to show that minute quantities of accessory gland secretion
achieve significant increases in sperm viability. Sperm stored by queens for 1 year benefited in a similar way from being
exposed to accessory gland compounds after dissection in control saline solution. Our results provide the first empirical
evidence that seminal fluid is important for the production of viable ejaculates and that the accessory glands of Atta males—despite their small size—are functional and produce a very potent secretion. 相似文献
177.
Nazario D. Ramírez‐Beltran Joan Manuel Castro Eric Harmsen Ramón Vásquez 《Journal of the American Water Resources Association》2008,44(4):847-865
Abstract: A practical methodology is proposed to estimate the three‐dimensional variability of soil moisture based on a stochastic transfer function model, which is an approximation of the Richard’s equation. Satellite, radar and in situ observations are the major sources of information to develop a model that represents the dynamic water content in the soil. The soil‐moisture observations were collected from 17 stations located in Puerto Rico (PR), and a sequential quadratic programming algorithm was used to estimate the parameters of the transfer function (TF) at each station. Soil texture information, terrain elevation, vegetation index, surface temperature, and accumulated rainfall for every grid cell were input into a self‐organized artificial neural network to identify similarities on terrain spatial variability and to determine the TF that best resembles the properties of a particular grid point. Soil moisture observed at 20 cm depth, soil texture, and cumulative rainfall were also used to train a feedforward artificial neural network to estimate soil moisture at 5, 10, 50, and 100 cm depth. A validation procedure was implemented to measure the horizontal and vertical estimation accuracy of soil moisture. Validation results from spatial and temporal variation of volumetric water content (vwc) showed that the proposed algorithm estimated soil moisture with a root mean squared error (RMSE) of 2.31% vwc, and the vertical profile shows a RMSE of 2.50% vwc. The algorithm estimates soil moisture in an hourly basis at 1 km spatial resolution, and up to 1 m depth, and was successfully applied under PR climate conditions. 相似文献
178.
Jason L. Huang 《组织行为杂志》2015,36(Z1):S53-S71
Modern work is frequently characterized by jobs where adaptive performance (AP) is crucial for employees to succeed in light of new or altered task demands. This recognition has fueled growing interest in AP as a dimension of workplace performance. To this point, however, research on AP has evolved from disparate perspectives and methods, resulting in fragmentation and a less than coherent knowledge base. This paper presents a comprehensive review of research studies regarding the nomological network of individual AP. In doing so, we synthesize the current knowledge base surrounding correlates of AP, elucidate current ambiguities, and suggest directions for future research efforts. We conclude that although the extant AP literature has amassed a critical body of studies linking various predictors to successful AP outcomes, much remains unknown, most critically regarding the implications of different methods of assessing AP, the effects of different types of changes in the task environment, the process of AP, and the steps organizations can take to foster AP among their employees. We hope that our synthesis and analysis paves the way for efforts to address these important questions. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
179.
为了寻找能同时降低卷烟烟气中甲醛、乙醛、巴豆醛和颗粒物有害成分含量的离子交换树脂吸附材料,采用电镜扫描方法观察聚丙烯基阳离子树脂高分子功能材料的表面特征,应用压汞法分析其平均孔径、中值孔径、比孔容和比表面积,并测试了该材料的交换容量,采用环境试验舱检测法对比测试了该材料和活性炭降低卷烟烟气中甲醛、乙醛、巴豆醛和颗粒物有害成分含量的效果.结果表明,聚丙烯基高分子功能材料表面多斑点状突起,凹凸状明显,微孔和缝隙多,平均孔径为0.26 μm,中值孔径为149.3 μm,比孔容为19.23 cm3/g,比表面积为293.42 m2/g,交换容量为5.16 mmol/g,对烟气中甲醛、乙醛、巴豆醛和颗粒物的净化率分别达到79.6%、79.8%、82.8%和64.7%,而活性炭的净化率分别为20.3%、0、6.4%和54.2%.研究表明,该聚丙烯基高分子功能材料具有物理吸附和化学吸附性能,净化卷烟烟气中多种有害成分的效果明显优于活性炭. 相似文献
180.
为弥补现有地下工程围岩稳定性评价方法的不足,建立了改进的物元可拓模型。通过构造一种新的关联函数,解决了因传统的物元可拓模型的关联函数是一个分段函数而存在的不便于计算的缺陷,以及评价指标间的互不相容性问题,拓宽了物元可拓法的应用范围。将改进的物元可拓模型应用于某地下工程围岩的稳定性评价,结果表明,样本1、2、5属于Ⅱ级(较稳定),样本3、4属于Ⅰ级(稳定)。通过将其评价结果与传统可拓法及模糊数学综合评判结果进行比较分析,证明该评价方法的正确性。研究表明,改进的物元可拓模型的评价结果与实际工程地质情况更为吻合,准确度更高,能够反映各因素对围岩稳定性的影响,其合理性和可行性得到了验证。 相似文献