It’s All in the Numbers: Acreage Tallies and Environmental Program Evaluation

Increasingly, performance measurement is being used to hold federal agencies accountable, represent environmental progress, and evaluate the effectiveness of environmental programs. The need to track measurable outputs has created a tendency to present programmatic progress solely by quantifiable data, despite the inherent complexity of natural resource management. Wetlands and fire management programs are two specific environmental arenas that have come to overemphasize the tracking of acreage numbers to validate existing policy direction. In both of these arenas, we find the definition and categorization of "countable" acres to be inconsistent and unreliable. We explore this systemic flaw for both wetlands and fire programs and describe its implications for environmental policy and natural resource management more broadly. We conclude with recommendations for improved performance measurement in these arenas.     

陕西绥德地区黄土-古土壤序列地球化学特征及其环境指示意义

黄土高原北部的绥德地区处于干旱-半干旱地区,对环境变化的响应十分敏感,通过对黄土-古土壤的研究对比可以探索该区的古环境气候特征、环境变化信息等相关问题.本文对绥德黄土-古土壤进行常量、微量、稀土元素测试分析,并与其他地区黄土的地球化学特征进行了对比.结果 表明:绥德地区黄土-古土壤的主要化学成分以SiO2、Al2O3、...     

变电站与输电线路的电磁环境影响水平分析与测试评估——以部分220kV及110kV输变电设施为例

通过对220kV及110kV户内布置、户外布置方式的变电站,架空输电线路以及地下电缆线的工频电场强度、工频磁场强度的监测,分析比较了变电站及输电线路对环境的贡献水平以及衰减规律。结果表明输变电设施对环境的贡献值非常有限,且随与之距离的增加而明显衰减。     

共模阻抗稳定网络的研制

为了消除辐射测试场地供电端口阻抗的差异,本文设计制作了一种共模阻抗稳定网络,可以在供电端口处提供稳定的共模阻抗。文中对该网络的技术参数、元件规格及分布参数控制提出设计方案.经实际制作与量测验证后,该稳定网络可以在30~300MHz的频段内提供稳定的阻抗(50±5?),符合设计方案的目标,利用此网络可有效消除供电端口阻抗差异引起的测试误差。     

The Convergence Analysis on the Economic Growth and Energy Intensity Gap between Regional Sectors

In this paper,the authors have analyzed the relationship between energy intensity gap and GDP per worker gap of China’s western and eastern provinces over the period 1997-2006.Using panel data model with lag adjustment,taking the above provinces and six industrial sectors (agriculture,forestry,animal husbandry,and fisheries,industry,construction industry,transport,storage and post & telecommunications,wholesale and retail trades & catering industry,and other sectors of tertiary industry.) as the investigated subjects,the authors have conducted empirical study on the convergence of GDP per worker gap and the convergence of energy intensity gap with respect to the variation of GDP per worker gap,and have concluded that:First,the GDP per worker gap of the six industrial sectors and provinces are convergent,and of this,the convergence rate of GDP per worker gap of Construction Industry is the fastest,while that of Industry is the slowest.Second,the overall energy intensity gap between eastern and western provinces is convergent,that is,with the narrowing of GDP per worker gap between eastern and western provinces,the energy intensity gap converges,but its convergence rate is slower than that of GDP per worker gap.Third,energy intensity gap between various industrial sectors of the east and the west is either convergent or divergent,and there are differences.The energy intensity gap of agriculture,forestry,animal husbandry,and fisheries,industry,and construction industry is convergent,while that of the other three industrial sectors is divergent.Fourth,the convergence of the overall energy intensity of the western provinces is not in conformity with the convergence of the various industrial sectors,and there are significant differences,indicating that the western provinces and autonomous regions should take measures to more effectively improve their overall energy utilization efficiency at the industrial sector level.     

能源强度收敛:对发达国家与发展中国家的检验

能源强度是指一个国家或地区生产单位产值所消耗的能源量,它反映了经济系统对能源的依赖程度和能源的使用效率。许多国家的能源强度曲线在直观上表现出收敛的显著特征。为了对这一现象进行严格的证明和检验,该文依据时间序列协整概念,首先提出了能源强度收敛的定义,然后从一个包含能源投入的内生增长模型出发,从理论上证实了能源强度收敛的存在性。为了对能源强度收敛进行实证检验,选取24个国家,并划分组合为5组样本,分别对能源强度收敛进行了σ收敛检验和协整检验,结果表明:高收入国家、高中收入国家、中低收入国家、发展中国家和样本中所有国家都存在能源强度收敛现象;σ收敛检验还揭示出各组样本中能源强度收敛的时间段以及收敛程度的大小排序。     

An Adaptive‐Management Framework for Optimal Control of Hiking Near Golden Eagle Nests in Denali National Park

Abstract: Unintended effects of recreational activities in protected areas are of growing concern. We used an adaptive‐management framework to develop guidelines for optimally managing hiking activities to maintain desired levels of territory occupancy and reproductive success of Golden Eagles (Aquila chrysaetos) in Denali National Park (Alaska, U.S.A.). The management decision was to restrict human access (hikers) to particular nesting territories to reduce disturbance. The management objective was to minimize restrictions on hikers while maintaining reproductive performance of eagles above some specified level. We based our decision analysis on predictive models of site occupancy of eagles developed using a combination of expert opinion and data collected from 93 eagle territories over 20 years. The best predictive model showed that restricting human access to eagle territories had little effect on occupancy dynamics. However, when considering important sources of uncertainty in the models, including environmental stochasticity, imperfect detection of hares on which eagles prey, and model uncertainty, restricting access of territories to hikers improved eagle reproduction substantially. An adaptive management framework such as ours may help reduce uncertainty of the effects of hiking activities on Golden Eagles.     

武宁县森林扰动及驱动因子分析

森林扰动是影响陆地生态系统的重要因子,也是影响全球碳循环的重要因素.以江西省武宁县为例,利用1986-2011年14景Landsat TM/ETM+遥感影像,通过扰动指数(disturbance index,DI)时间序列轨迹分析提取森林扰动信息,并引入经验正交函数(empirical orthogonal function,EOF)分解方法定量分析了森林扰动的时空变化规律,利用GIS深入分析了自然和社会驱动因子影响.结果表明,武宁县森林扰动在1986-1998年较强,扰动面积以1992年为最大,以地区性扰动为主;2000年以后则趋于平缓,扰动以砍伐和森林火灾为主;在空间上,扰动主要发生在近道路、低海拔、低坡度和近水地区,并受地形和交通的制约,城镇化逐渐成为该地区森林扰动的一个不可忽略的驱动因子.     

Flame Propagation Across Gelled Alkane-In-Water Emulsions

Flame propagation rates were measured for flames spreading across surfaces of gel-like alkane-in-water emulsions. A long, slender, water-cooled trough was used to contain the mixtures. Abrupt changes in the flame propagation velocities - of nearly two orders of magnitude - were observed to occur near ‘critical’ concentrations of certain alkane/water mixtures. Four alkanes were used - pentane, hexane, heptane, and octane - and fuel rich emulsions (in which water was the continuous phase) were employed. The ability of the aqueous phase of the emulsion to inhibit the release of fuel into the vapor phase plays an important role in the observed behavior. That is, the rate at which fuel can diffuse through both the emulsion and the thin liquid layers that reside on it, is an essential kinetic aspect of the phenomena which determine the flame propagation rate across gelled alkane-in-water emulsions.     

Forest Stand Dynamics and Livestock Grazing in Historical Context

Abstract:  Livestock grazing has been implicated as a cause of the unhealthy condition of ponderosa pine forest stands in the western United States. An evaluation of livestock grazing impacts on natural resources requires an understanding of the context in which grazing occurred. Context should include timing of grazing, duration of grazing, intensity of grazing, and species of grazing animal. Historical context, when and under what circumstances grazing occurred, is also an important consideration. Many of the dense ponderosa pine forests and less-than-desirable forest health conditions of today originated in the early 1900s. Contributing to that condition was a convergence of fire, climate, and grazing factors that were unique to that time. During that time period, substantially fewer low-intensity ground fires (those that thinned dense stands of younger trees) were the result of reduced fine fuels (grazing), a substantial reduction in fires initiated by Native Americans, and effective fire-suppression programs. Especially favorable climate years for tree reproduction occurred during the early 1900s. Exceptionally heavy, unregulated, unmanaged grazing by very large numbers of horses, cattle, and sheep during the late nineteenth and early twentieth centuries occurred in most of the U.S. West and beginning earlier in portions of the Southwest. Today, livestock numbers on public lands are substantially lower than they were during this time and grazing is generally managed. Grazing then and grazing now are not the same.