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81.
Institutions managing the Alaska road,rail, airport, and marine highwaytransportation system and the pipelinecorridor are evaluated for reactions toevidence of climate change. Long-termclimate warming is not a formal criterionin the decisional process of the stateDepartment of Transportation and PublicFacilities for road and airport projects,which have a short (15–25 year) life span,but is taken into account for bridgeconstruction (50–75 year life). Short- tomid-term climate effects are considered inareas with discontinuous permafrost andaffect routing, roadbed construction, andmaintenance decisions. National standardsare amended with Alaska-specific practicesfor unique cold-weather conditions.The Federal/State Joint Pipeline Office(JPO), responsible for monitoring ofpipeline safety under the federal lease andstate grant, in 2001 developed additionalstipulations to mitigate permafrost thawingand slope instability, including a `watchlist' of 200 wobbling VSMs on theTrans-Alaska Pipeline. This action appearsmore responsive to climate change effectsthan that of any other arctic institutionstudied. It can be attributed to thespecific authority of the JPO to monitorgeotechnical conditions at present and inthe future.In general, agencies tended to adoptincremental responses to evidence ofclimate change. 相似文献
82.
美国环境管理体系中联邦与地方政府角色透视 总被引:4,自引:0,他引:4
Mary A.Gade Cynthia A.Faur 《环境科学研究》2006,19(Z1):126-132
自美国环境保护局(EPA)成立以来,美国各州的环境执政体制产生了巨大的变化,取得了卓越的成绩.美国的环境执政体制从分权的、由州驱动的体制演变为自上而下、技术强制、联邦驱动的体制.近几年该体制更加分权化,各州的作用更为强大;引入了市场力量,加强了环境保护力度,成本竞争力亦得到改善.自上而下/技术强制的体制和以非集权化/市场为主的体制有其各自的优缺点.笔者将试图阐明环境保护体制的良好运转同时需要来自这2种方式的元素. 相似文献
83.
Kari Rasilainen Juhani Suksi Timo Ruskeeniemi Petteri Pitknen Antti Poteri 《Journal of contaminant hydrology》2003,61(1-4):235
Uranium release observed in a rock matrix around water-carrying fractures was studied using U-series disequilibrium (USD) modelling and mass balance calculations. Several release scenarios were tested, with specific attention to the glacial aspects. The release appears to have occurred in two or three violent episodes during the last 300 ky. A release after the last glaciation can be excluded on mass flow grounds. Continuous release for more than 300 ky can be excluded on radioactive disequilibrium grounds. Repeated inflows of oxic glacial meltwater seem to have triggered the release episodes. 相似文献
84.
美国高等职业教育的特点 总被引:6,自引:1,他引:6
美国职业教育立法具有阶段性、可操作性、科学性和先行性;高中后为非义务大学教育,包括综合性或研究型大学、普通本科大学和社区学院.社区学院主要承担高等职业教育,实行联邦政府引导、州政府和地方政府分级管理,重心是地方管理;职业教育改革的基本理论主要有人力资本理论和批判理论;形成了形式多样、多维交叉的办学格局,培养目标明确,强调技艺和操作技能,培养中级技术员;人才规格是“5种能力和3种素质”;课程体系包括普通课程、职业课程与学术课程,课程设置具有高度灵活多样和应用性;课程改革主要形式有合作学习、课程整合和STW课程框架;教师任职资格的标准很高,对教师管理非常严格,实行教师资格证书制;产教合作又称为“合作职业教育”,包括以雇主为基础的模式、收办学校模式和学习与就业连结模式;经费来源渠道主要是当地财产税、州政府拨款、联邦政府资助和学生学费. 相似文献
85.
Joseph J. Valadez 《Journal of environmental psychology》1984,4(3):223-228
Previous research has shown that designers' and architects' evaluations of visual stimuli, and of urban and rural environments are not necessarily shared by non-designers and non-architects. Such conclusions may be biased by instrumentation and methodological problems, namely, previous instruments often require verbal responses about stimuli. Hence, non-designers and non-architects may be less capable in expressing themselves, but perceive the same things as the professionals. Another problem stems from professionals who have a narrow range of traits being compared with a general population that has a broader range of traits and therefore has greater within-group variance. This study presents an instrument and a methodology for dealing with these problems in addition to examining the perceptual orientations of architects in comparison to three other professions. Results indicate that architects varied from the other professional groups in their quantitative judgments of the habitats studied but not from all groups in their qualitative judgments. Hence, architects may be a distinct professional culture for some design variables only. 相似文献
86.
This study examines the normative functioning of the volcano warning system on the Island of Hawaii. The research seeks to identify the combination of factors, both environmental and social, which allows the system to operate with success. On the basis of the findings, several recommendations are offered for improving environmental hazard warning systems. 相似文献
87.
Wildfire Policy and Public Lands: Integrating Scientific Understanding with Social Concerns across Landscapes 总被引:4,自引:0,他引:4
Abstract: Efforts to suppress wildfires have become increasingly problematic in recent years as costs have risen, threats to firefighter safety have escalated, and detrimental impacts to ecosystems have multiplied. Wildfires that escape initial suppression often expand into large, high-intensity summer blazes. Lost is the legacy of smaller fires that likely burned outside extreme weather and fuel conditions and resulted in less severe impacts. Despite the recognized need for modifications to existing policies and practices, resource agencies have been slow to respond. The spread of exotic species, climate change, and increasing human development in wildlands further complicates the issue. New policies are needed that integrate social and ecological needs across administrative boundaries and broad landscapes. These policies should promote a continuum of treatments with active management and reduction of fuel hazard in wildland-urban interface zones and reintroduction of fire in wildlands. Management goals should focus on restoration of the long-term ecological health of the land. Projects that reduce fuel loads but compromise the integrity of soil, water supplies, or watersheds will do more harm than good in the long run. Despite significant ecological concerns, learning to live with fire remains primarily a social issue that will require greater political leadership, agency innovation, public involvement, and community responsibility. 相似文献
88.
文章从生态安全的研究现状入手,根据生态系统和人类社会系统之间的主要关系,论述了生态安全弹性和安全"倒U"曲线理论.生态安全弹性能够反映安全系数、安全阈值、干扰程度三者的关系,由它来判断人类向生态系统索取自然资源的活动更具有预测性、可操作性,并能保证生态系统自身也处于可持续发展的良性状态. 相似文献
89.
The survey of the incidence of chromosome mosaicism and pseudomosaicism detected in prenatal diagnosis included data from approximately 60 000 genetic amniocenteses in the United States. There were 59 participating cytogenetic laboratories nationwide. The overall incidence of chromosome mosaicism was 0.25 per cent (range of 0–0.89 per cent). The average frequency of pseudomosaicism involving multiple cells or clones was 0.7 per cent (range of 0–11.21 per cent). The frequency of single cell or clone pseudomosaicism was 2.47 per cent (range of 0–11.49 per cent). In cases of pseudomosaicism with trisomy, the most frequently involved chromosome was number 2; occurrence rates of trisomies 7,X,9,17 and 20 were also relatively high. In cases of pseudomosaicism with structural abnormalities, this survey showed an association between relative chromosome size and the frequency of involvement in structural rearrangement. Data on a total of 185 cases of chromosome mosaicism collected in this survey as well as from other documented sources showed 89 cases involved an autosome, 13 cases a sex chromosome, and 23 a marker chromosome. The frequency of noticeable phenotypic abnormalities was highest (37.8 per cent) in the autosomal mosaics and lowest (10.5 per cent) in the sex chromosome mosaics. The average rate for cytogenetic confirmation was 70 per cent. 相似文献
90.
A Nationwide Analysis of U.S. Army Corps of Engineers Reservoir Performance in Meeting Operational Targets
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Lauren A. Patterson Martin W. Doyle 《Journal of the American Water Resources Association》2018,54(2):543-564
The United States (U.S.) Army Corps of Engineers operates reservoirs across the U.S. with 89% of reservoirs constructed prior to 1980. Many reservoirs have experienced changes in environmental conditions (e.g., climate and sediment yield) and societal conditions (e.g., water/energy demand and ecological flows) since construction. These changes may challenge the potential for reservoirs to meet their operational targets (OTs) (management goals). Historic daily reservoir data and OTs were collected for 233 reservoirs. Analyses were developed to identify when and where reservoirs may be systematically departing from OTs in terms of the frequency and magnitude of departure. Fifty‐six percent of reservoirs consistently met operating targets, 30% were borderline, and 13% experienced frequent and large magnitude departures. Fifty‐two percent of reservoirs with large departures were due to shortages and were located in the South Pacific and Southwestern divisions. This work provides a framework to identify reservoir performance in relation to management goals, a necessary step for moving toward adaptive management under changing conditions. All individual reservoir analyses are provided via an interactive data visualization tool: https://nicholasinstitute.duke.edu/reservoir-data . 相似文献