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71.
Gerald T. Westbrook 《The Environmentalist》1981,1(3):197-205
Summary An earlier version of this paper was originally presented at The American Association of University Women, Michigan, State Division, USA. The paper deals with two main issues: In the first place that there is no single energy source that will solve the energy problem. The solution will come through what has been called An Energy Family Approach. Secondly, that government regulations, which were primarily written in the days when America was viewed as a country with no limits, must be relaxed.Gerald T. Westbrook works for Dow's Hydrocarbons Department as Energy Project Manager. Prior to this current assignment he had been Project Manager in Dow's Functional Products and Systems Department for Business Development concentrating on water purification technologies for the energy industries. He has had over twenty years experience in various technical and functional areas with Dow Chemical in the United States and Imperial Oil Ltd. in Canada. Experience in the energy field has included petroleum refinery design and operations analysis; electric power plant planning, and water systems development; new advanced battery development; and energy economics and forecasting. 相似文献
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Evaluating progress towards environmental sustainability goals can be difficult due to a lack of measurable benchmarks and insufficient or uncertain data. Marine settings are particularly challenging, as stakeholders and objectives tend to be less well defined and ecosystem components have high natural variability and are difficult to observe directly. Fuzzy logic expert systems are useful analytical frameworks to evaluate such systems, and we develop such a model here to formally evaluate progress towards sustainability targets based on diverse sets of indicators. Evaluation criteria include recent (since policy enactment) and historical (from earliest known state) change, type of indicators (state, benefit, pressure, response), time span and spatial scope, and the suitability of an indicator in reflecting progress toward a specific objective. A key aspect of the framework is that all assumptions are transparent and modifiable to fit different social and ecological contexts. We test the method by evaluating progress towards four Aichi Biodiversity Targets in Canadian oceans, including quantitative progress scores, information gaps, and the sensitivity of results to model and data assumptions. For Canadian marine systems, national protection plans and biodiversity awareness show good progress, but species and ecosystem states overall do not show strong improvement. Well-defined goals are vital for successful policy implementation, as ambiguity allows for conflicting potential indicators, which in natural systems increases uncertainty in progress evaluations. Importantly, our framework can be easily adapted to assess progress towards policy goals with different themes, globally or in specific regions. 相似文献
74.
A. Ann Sorensen Tana M. Busch S. Bradleigh Vinson 《Behavioral ecology and sociobiology》1985,17(3):191-198
Summary Temporal subcastes in the fire ant, Solenopsis invicta Buren were selectively starved to determine if foragers could assess the nutritional status of their nestmates and respond accordingly. We found that starved foragers increase the honey entering the colony (Fig. 1). When nurses are starved more oil and liquid egg yolk enters the colony (Figs. 2, 3) and when both reserves and nurses are starved, more egg yolk powder is brought in by the foragers (Fig. 4). When queens are starved, more liquid egg yolk and oil enters the colony (Figs. 2, 3). Starved larvae increase the oil in the colony (Fig. 2) and when held with nurses for 24h before feeding, increase the egg yolk powder brought in and receive significantly more of it than other subcaste members (Fig. 5). We conclude that foragers can respond to the nutritional needs of their nestmates. Based on our behavioural observations, the quantity of food brought in by the foragers is regulated via discriminatory solicitation by reserves in response to the nutritional needs of the nurses. 相似文献
75.
Gerald G. Garland 《Environmental management》1990,14(6):793-798
One of the most pressing problems facing wilderness managers in the ecologically fragile Drakensberg Mountains, South Africa,
is that of path erosion, since it detracts from the wilderness experience and is very costly to remediate. As increasing demand
for wilderness and outdoor recreation places greater pressure on paths and trails, it will be necessary to increase path network
size and capacity, and it is important that new paths are routed such that maintenance requirements are minimal.
This study describes the development of a technique based on the site and environmental variables of rainfall, topographic
slope, and lithology, which enables assessment of path erosion risk before paths are planned and constructed. The technique
was tested on a path at the Drakensberg resort of Loteni, and showed good correlation with actual path degradation. When used
as a tool in path network planning, it can aid in the selection of low-maintenance routes and also help in planning maintenance
budgets. 相似文献
76.
Overview of case studies on recovery of aquatic systems from disturbance 总被引:13,自引:2,他引:13
Gerald J. Niemi Philip DeVore Naomi Detenbeck Debra Taylor Ann Lima John Pastor J. David Yount Robert J. Naiman 《Environmental management》1990,14(5):571-587
An extensive review of the published literature identified more than 150 case studies in which some aspect of resilience in
freshwater systems was reported. Approximately 79% of systems studied were lotic and the remainder lentic. Most of the stressor
types were chemical with DDT (N=29) and rotenone (N=15) the most common. The most common nonchemical stressors were logging
activity (N=16), flooding (N=8), dredging (N=3), and drought (N=7).
The variety of endpoints to which recovery could be measured ranged from sparse data for phytoplankton (N=13), periphyton
(N=6), and macrophytes (N=8) to relatively more data for fish (N=412) and macroinvertebrates (N=698). Unfortunately the same
characteristics were rarely measured consistently among sites. For example, with respect to fish, more than 30 different species
were studied and recovery was measured in many ways, most commonly on the basis of: (1) first reappearance of the species,
(2) return time of predisturbance densities, and (3) return time of predisturbance average individual size. Based on these
criteria, all systems in these studies seem to be resilient to most disturbances with most recovery times being less than
three years. Exceptions included when (1) the disturbance resulted in physical alteration of the existing habitat, (2) residual
pollutants remained in the system, or (3) the system was isolated and recolonization was suppressed. 相似文献
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L. Pat Robinson Nancy J. Worthen Ralph S. Lachman Gerald E. Adomian David L. Rimoin 《黑龙江环境通报》1987,7(1):7-15
Ultrasonographic and radiographic evaluation of a fetus at risk for osteogenesis imperfecta (O.I) type III was performed. Real-time ultrasound measurements at 15 weeks gestation were interpreted as normal, but at 20 and 22 weeks of gestation revealed marked shortening of the long bones and deformity of the femurs. The findings were confirmed by fetal radiography at 22 weeks gestation. Radiographic and histologic changes characteristic of O.I. were observed in the aborted fetus. Thus the antenatal manifestations of O.I. type III maybe severe enough to make prenatal diagnosis possible in the second trimester for families at risk for recurrence of this disorder. 相似文献
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