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531.
As habitat loss continues, natural protected areas will become islands in human-modified landscapes; maintenance of functional communities and ecosystems will depend on properly designed protected areas. We demonstrate that incorporating regional habitat linkages that allow for seasonal migrations of intratropical resident species must be a major design criterion for establishing protected areas. Using radiotelemetry, we monitored the seasonal movements of one such migrant, the Resplendent Quetzal ( Pharomachrus mocinno ), a large, frugivorous bird, one of many tropical residents known to migrate altitudinally within Mesoamerica. Based on three years of data we determined that quetzals followed a complicated local migration that linked four montane life zones. Using this species as an indicator revealed that the configuration of the Monteverde reserve complex in the Tilaran Mountains in west-central Costa Rica lacked sufficient habitat distribution to conserve montane biodiversity. On the basis of these results, we propose that the three-step process proposed by Soulé and Simberloff (1986) for estimating minimum sizes of reserves be amended to include a fourth step: The critical habitats used throughout the annual cycles of target or keystone species must be identified and adequately protected. Natural protected areas can be considered adequately designed only when sufficient area with a full complement of ecologically linked habitats is included.  相似文献   
532.
Photochemical aging of volatile organic compounds (VOCs) in the atmosphere is an important source of secondary organic aerosol (SOA). To evaluate the formation potential of SOA at an urban site in Lyon (France), an outdoor experiment using a Potential Aerosol Mass (PAM) oxidation flow reactor (OFR) was conducted throughout entire days during January-February 2017. Diurnal variation of SOA formations and their correlation with OH radical exposure (OHexp), ambient pollutants (VOCs and particulate matters, PM), Relative Humidity (RH), and temperature were explored in this study. Ambient urban air was exposed to high concentration of OH radicals with OHexp in range of (0.2–1.2)×1012 molecule/(cm3?sec), corresponding to several days to weeks of equivalent atmospheric photochemical aging. The results informed that urban air at Lyon has high potency to contribute to SOA, and these SOA productions were favored from OH radical photochemical oxidation rather than via ozonolysis. Maximum SOA formation (36 µg/m3) was obtained at OHexp of about 7.4 × 1011molecule/(cm3?sec), equivalent to approximately 5 days of atmospheric oxidation. The correlation between SOA formation and ambient environment conditions (RH & temperature, VOCs and PM) was observed. It was the first time to estimate SOA formation potential from ambient air over a long period in urban environment of Lyon.  相似文献   
533.
Heterogeneous reactions of NO2 on different surfaces play an important role in atmospheric NOx removal and HONO formation, having profound impacts on photochemistry in polluted urban areas. Previous studies have suggested that the NO2 uptake on the ground or aerosol surfaces could be a dominant source for elevated HONO during the daytime. However, the uptake behavior of NO2 varies with different surfaces, and different uptake coefficients were used or derived in different studies. To obtain a more holistic picture of heterogeneous NO2 uptake on different surfaces, a series of laboratory experiments using different flow tube reactors was conducted, and the NO2 uptake coefficients (γ) were determined on inorganic particles, sea water and urban grime. The results showed that heterogeneous reactions on those surfaces were generally weak in dark conditions, with the measured γ varied from <10?8 to 3.2 × 10?7 under different humidity. A photo-enhanced uptake of NO2 on urban grime was observed, with the obvious formation of HONO and NO from the heterogeneous reaction. The photo-enhanced γ was measured to be 1.9 × 10?6 at 5% relative humidity (RH) and 5.8 × 10?6 at 70% RH on urban grime, showing a positive RH dependence for both NO2 uptake and HONO formation. The results demonstrate an important role of urban grime in the daytime NO2-to-HONO conversion, and could be helpful to explain the unknown daytime HONO source in the polluted urban area.  相似文献   
534.
Environmental Science and Pollution Research - The determination of trace metals and organic contaminants in environmental samples, such as water, air, soil, and sediment, is until today a...  相似文献   
535.
536.
Environmental Science and Pollution Research - This study reports the enhanced chemical resistance of a blended concrete mix (CFNI) made with 40 wt.% fly ash, 2 wt.% nanoparticles, and 2 wt.%...  相似文献   
537.
An overview of the methods used for the isolation and characterization of organic matter in natural waters is presented. Commonly used techniques for the concentration and isolation of organic matter from water, such as preparative chromatography, ultrafiltration and reverse osmosis, and the methods used to analyze the organic matter obtained by these methods are reviewed. the development of methods to obtain organic matter that is associated with fractions of the dissolved organic carbon other than humic substances, such as organic bases, hydrophilic organic acids and colloidal organic matter are discussed. Methods specifically used to study dissolved organic nitrogen and dissolved organic phosphorous are also discussed.  相似文献   
538.
There is limited evidence to suggest that certain compounds of cadmium may be mildly mutagenic. Some compounds of cadmium have given rise to fibrosarcoma and rhabdomyosarcoma following subcutaneous or intramuscular injection in the rat and also to interstitial cell tumours of the testis as a sequel to cellular damage and testicular atrophy. Cadmium chloride aerosol inhalation has induced a high incidence of dose‐related lung cancer in the rat. Epidemiological observations suggest that mortality from prostatic and possibly from lung cancer has been increased in cadmium workers who had experienced the very high levels of cadmium, mainly as oxide dust or fume, which existed in the past. The more recent epidemiological studies have not added further evidence in support of the carcinogenic role of cadmium.  相似文献   
539.
SUMMARY

The Rio Earth Summit and publication and distribution of Agenda 21 (UN, 1992) have generated much activity in many nations towards development and implementation of community indicators of sustainable development (SI). In recent years efforts at development and implementation of SI have intensified at regional and urban government levels, although fewer efforts are evident at a rural community level. In response to initial ad hoc efforts, methodologies for SI construction are currently being proposed, tested and refined. Within this evolutionary process, increasing recognition is being given to the critical need for, and importance of, ‘stakeholder’ involvement in SI development and implementation. This paper critically reviews these and related efforts from the perspective of rural communities in Canada. The argument is presented that the process of development and implementation of rural community-level SI can significantly benefit from development and implementation of a methodological approach in support of principles and practices of effective stakeholder involvement. It is further argued that development of SI must be stakeholder-driven, and that a pivotal element in the SI development process is the facilitation of information sharing. The paper concludes with a proposal for an approach to stakeholder participation and information sharing achieved through research, testing and refinement, and integration of these concepts within the process of rural community sustainable indicator development.  相似文献   
540.
In the United States local land trusts preserve and conserve land to protect water quality and supply, farmlands, habitat for native plants and animals, areas of cultural or historical significance, and scenic views. We surveyed the 24 active, local land trusts in North Carolina (U.S.A.) to determine how they report progress toward attaining such conservation goals. Twenty-two land trusts responded to our survey. Of these, eight reported developing specific conservation goals for all of the properties they protect, five identified conservation targets on all properties, and two reported monitoring biological indicators on all of their protected properties. On the basis of these results, we believe most of the land trusts surveyed could not determine whether they were meeting conservation goals because most did not identify explicit, measurable goals and monitor progress toward them. Instead they reported success in terms of the amount of land protected and money raised. We think this is a lost opportunity for land trusts to build sound approaches to environmental management, engage the public, entice new donors, and attain funding for additional conservation activities. We propose conservation professionals help local land trusts adopt the Open Standards for the Practice of Conservation, a framework developed by a consortium of international conservation organizations, to develop conservation goals and measure whether the goals are achieved.  相似文献   
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