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401.
402.
Norman LM Gray F Guertin DP Wissler C Bliss JD 《Environmental monitoring and assessment》2008,145(1-3):145-157
This study investigates the application of models traditionally used to estimate erosion and sediment deposition to assess the potential risk of water quality impairment resulting from metal-bearing materials related to mining and mineralization. An integrated watershed analysis using Geographic Information Systems (GIS) based tools was undertaken to examine erosion and sediment transport characteristics within the watersheds. Estimates of stream deposits of sediment from mine tailings were related to the chemistry of surface water to assess the effectiveness of the methodology to assess the risk of acid mine-drainage being dispersed downstream of abandoned tailings and waste rock piles. A watershed analysis was preformed in the Patagonia Mountains in southeastern Arizona which has seen substantial mining and where recent water quality samples have reported acidic surface waters. This research demonstrates an improvement of the ability to predict streams that are likely to have severely degraded water quality as a result of past mining activities. 相似文献
403.
This paper presents an air-quality surveillance system designed to detect the occurrence of air pollutant concentrations greater
than a reference level in an urban area. The system is integrated by an air-quality monitoring network and atmospheric dispersion
models simulations. An objective methodology to design an urban air-quality monitoring network is proposed. This methodology
is based on the analysis of air-quality modelling results. The procedure is applied to design an air-quality monitoring network
to control NO
x
concentration levels in Buenos Aires City. Results indicate that six monitors will detect the occurrence of concentration
greater than the air-quality guidelines with an efficiency of about 67%. Once a violation is detected, results of atmospheric
dispersion models will help in the determination of affected areas. Four possible examples are included to illustrate the
assistance that the results of atmospheric dispersion models can bring to a better estimation of possible affected areas in
the city. Combining these results with the last census data, an estimation of the inhabitants possibly exposed is obtained. 相似文献
404.
405.
Carranza ML Acosta AT Stanisci A Pirone G Ciaschetti G 《Environmental monitoring and assessment》2008,140(1-3):99-107
Many recent developments in coastal science have gone against the demands of European Union legislation. Coastal dune systems
which cover small areas of the earth can host a high level of biodiversity. However, human pressure on coastal zones around
the world has increased dramatically in the last 50 years. In addition to direct habitat loss, the rapid extinction of many
species that are unique to these systems can be attributed to landscape deterioration through the lack of appropriate management.
In this paper, we propose to use of an ecosystem classification technique that integrates potential natural vegetation distribution
as a reference framework for coastal dune EU Habitats (92/43) distribution analysis and assessment. As an example, the present
study analyses the EU Habitats distribution within a hierarchical ecosystem classification of the coastal dune systems of
central Italy. In total, 24 land elements belonging to 8 land units, 5 land facets, 2 land systems and 2 land regions were
identified for the coastal dunes of central Italy, based on diagnostic land attributes. In central Italy, coastal dune environments
including all the beach area, mobile dunes and all the fixed-dune land elements contain or could potentially hold at least
one EU habitat of interest. Almost all dune slack transitions present the potentiality for the spontaneous development of
EU woodlands of interest. The precise information concerning these ecosystems distribution and ecological relationships that
this method produces, makes it very effective in Natura 2000 European network assessment. This hierarchical ecosystem classification
method facilitates the identification of areas to be surveyed and eventually bound, under the implementation of EU Habitat
directive (92/43) including areas with highly disturbed coastal dune ecosystems. 相似文献
406.
Annalies Borrel Anna Taylor Marie McGrath rew Seal Elizabeth Hormann Laura Phelps & Frances Mason 《Disasters》2001,25(2):149-163
The preparation and dissemination of policy statements are necessary but insufficient to prevent the inappropriate use of infant-feeding products in emergencies. The widespread failure of humanitarian agencies operating in the Balkan crisis to act in accordance with international policies and recommendations provides a recent example of the failure to translate infant-feeding policies into practice. This article explores the underlying reasons behind the failures which include: (1) the weak institutionalisation of policies; (2) the massive quantities of unsolicited donations of infant-feeding products: (3) the absence of monitoring systems; (4) inadequate co-ordination mechanisms; (5) the high costs of correcting mistakes; and (6) the cumulative effects of poor practice. Efforts to uphold best practice during the crisis are also documented. Finally, the article identifies actions that could be undertaken in advance of and during future emergencies to enhance the application of infant feeding policies in emergencies. 相似文献
407.
Amphibian Declines and Environmental Change: Use of Remote-Sensing Data to Identify Environmental Correlates 总被引:3,自引:0,他引:3
408.
Predators can have significant nonlethal effects on prey by modifying prey behaviour through chemically mediated interactions.
We examined behavioural responses of wood frog (Ranasylvatica) and American toad (Bufoamericanus) tadpoles to both direct and indirect chemical signals associated with a predatory odonate (Anaxjunius). In laboratory trials, tadpoles of both species responded strongly to water conditioned with Anax nymphs by decreasing foraging rates, becoming immobile, and moving away from the stimulus. The responses to water conditioned
with starved Anax versus Anax that fed on conspecific tadpoles did not differ significantly; these results suggest that tadpoles rely primarily on direct
signals to detect odonates. Rana did not respond to water conditioned with conspecific tissue extracts, while Bufo responded with behaviours that were indistinguishable from those of tadpoles exposed to Anax chemicals. In a field experiment, the responses of R. sylvatica tadpoles to Anax chemicals were similar to those of tadpoles observed in the laboratory. Collectively, our data indicate that tadpoles of
both species use chemical cues to assess predation risk from other community members. Tadpoles can selectively distinguish
members who pose a threat, and only evacuate food patches or reduce foraging rates when in danger. These behaviours appear
to be adaptive and are consistent with the predictions of optimality theory.
Received: 1 August 1997 / Accepted after revision: 22 November 1997 相似文献
409.
Assessments of adaptation options generally focus on incremental, homogeneous ecosystem responses to climate even though climate
change impacts can be big, fast, and patchy across a region. Regional drought-induced tree die-off in semiarid woodlands highlights
how an ecosystem crash fundamentally alters most ecosystem services and poses management challenges. Building on previous
research showing how choice of location is linked to adaptive capacity and vulnerability, we developed a framework showing
how the options for retaining desired ecosystem services in the face of sudden crashes depend on how portable the service
is and whether the stakeholder is flexible with regard to the location where they receive their services. Stakeholders using
portable services, or stakeholders who can move to other locations to obtain services, may be more resilient to ecosystem
crashes. Our framework suggests that entering into cooperative networks with regionally distributed stakeholders is key to
building resilience to big, fast, patchy crashes. 相似文献
410.
A recycled polyethylene was fed in a pilot plant bubbling fluidized bed gasifier, having an internal diameter of 0.381 m and a maximum feeding capacity of 90 kg/h. The experimental runs were carried out under various operating conditions: the bed temperature was kept at about 850 degrees C, the equivalence ratio varied between 0.2 and 0.35, the amount of bed material was between 131 and 215 kg, the fluidizing velocity was between 0.5 and 0.7 m/s, quartz sand and olivine were used as bed material, and air and steam were used as fluidizing reactants. The results confirm that the tar removal treatments applied inside the gasifier (primary methods) can eliminate or strongly reduce the need for a further downstream cleanup of the syngas. In particular, the utilization of a natural olivine as an in situ tar reduction agent remarkably improves the quality of the product gas, in terms of both high hydrogen volumetric fraction and larger syngas yield. 相似文献