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611.
Two major multidisciplinary bibliographic databases, the Science Citation Index and the Social Science Citation Index were searched to collect science and social science journal articles published in the 1987–2001 period with the report Our Common Future among their references. A statistical overview is given about the trends and patterns revealed by the bibliometric/scientometric analysis of the retrieved literature. National and regional distributions as well as publication channels and thematic features are considered. During the period under study, the word sustainability became the dominating term of the field, and operative questions like those of management, technology and urbanization came into the forefront of interest.Readers should send their comments on this paper to:BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
612.
Climate change resulting from the enhanced greenhouse effect is expected to give rise to changes in hydrological systems. This hydrological change, as with the change in climate variables, will vary regionally around the globe. Impact studies at local and regional scales are needed to assess how different regions will be affected. This study focuses on assessment of hydrological impacts of climate change over a wide range of Swedish basins. Different methods of transferring the signal of climate change from climate models to hydrological models were used. Several hydrological model simulations using regional climate model scenarios from Swedish Regional Climate Modelling Programme (SWECLIM) are presented. A principal conclusion is that subregional impacts to river flow vary considerably according to whether a basin is in northern or southern Sweden. Furthermore, projected hydrological change is just as dependent on the choice of the global climate model used for regional climate model boundary conditions as the choice of anthropogenic emissions scenario. 相似文献
613.
Radon gas concentrations have been monitored as part of the operation of a tunnel (the Exploratory Studies Facility-ESF) at Yucca Mountain to ensure worker safety. The objective of this study was to examine the potential use of the radon data to estimate large-scale formation properties of fractured tuffs. This objective was examined by developing a numerical model, based upon the characteristics of the ESF and the Topopah Spring welded (TSw) tuff unit, capable of predicting radon concentrations for prescribed ventilation conditions. The model was used to address two specific issues. First, it was used to estimate the permeability and porosity of the fractures in the TSw at the length scale of the ESF and extending tens of meters into the TSw, which surrounds the ESF. Second, the model was used to understand the mechanism leading to radon concentrations exceeding a specified level within the ESF. The mechanism controlling radon concentrations in the ESF is a function of atmospheric barometric fluctuations being propagated down the ESF along with ventilated air flow and the slight suction induced by the ventilation exhaust fans at the South Portal of the ESF. These pressure fluctuations are dampened in the TSw fracture continuum according to its permeability and porosity. Consequently, as the barometric pressure in the ESF drops rapidly, formation gases from the TSw are pulled into the ESF, resulting in an increase in radon concentrations. Model calibration to both radon concentrations measured in the ESF and gas-phase pressure fluctuations in the TSw yielded concurrent estimates of TSw fracture permeability and porosity of 1 x 10(-11) m2 and 0.00034, respectively. The calibrated model was then used as a design tool to predict the effect of adjusting the current ventilation-system operation strategy for reducing the probability of radon gas concentrations exceeding a specified level. 相似文献
614.
This work, on the ashes from the wastewater treatment plant of Galindo (Vizcaya, Spain), has been outlined with the purpose of finding their physico-chemical properties and suggesting possible applications. Ashes contain important quantities of iron, calcium, silica, alumina and phosphates. X-Ray diffraction data make it possible to estimate the mineralogical compositions of the original ashes and also, after thermal treatment at 1200 and 1300 degrees C, the main reactions occurring in thermal treatment. Particle size analysis makes it possible to classify ashes as a very fine powdered material. The thermal treatment leads to a densification of the material and provokes losses of weight mainly due to the elimination of water, carbon dioxide and sulphur trioxide. Application tests show that ashes are not suitable for landfill and similar applications, because of their plastic properties. Testing for pozzolanic character, after the ashes had been heated at 1200 degrees C, did not lead to a strong material probably due to low contents in silica and alumina or to requiring a higher heating temperature. Thermal treatment leads to densification of the material with a considerable increase of compressive strength of the probes. The use of additives (clays and powdered glass) to improve ceramic properties of ashes will be the aim of a future work. 相似文献
615.
Andreani-Aksoyoglu Sebnem Keller Johannes Dommen Josef Prévôt André S. H. 《Water, Air, & Soil Pollution: Focus》2003,3(5-6):289-305
The three-dimensional Eulerian model CAMx (Comprehensive Air QualityModel with Extensions) was applied for the first time to simulate bothgaseous and particulate photochemical air pollution in Switzerland during July 28–30, 1993. The meteorological input data were prepared using the Systems Applications International Mesoscale Model (SAIMM). The CAMx model results were compared with the measurements carried out at ground level andfrom airborne measuring platforms within the frame of the Swiss POLLUMET research programme. In general, the CAMx performance for gaseous species wasfound to be better than that of the previously used Urban Airshed Model (UAM)and the Variable Grid Urban Airshed Model (UAM-V). The most significant improvement for the gaseous species is in the prediction of HNO3 concentrations, due to the inclusion of aerosol chemistry. Aerosol species such as NO3
-, NH4
+, SO4
2-, and secondary organic aerosols were calculated in one particle size range (0.04–2.5 m) and compared with a few measurements available. Although July 29 was reasonably well simulated, overestimated wind speeds by SAIMM for July 30 caused a too fast transport of pollutants. Similarly to measurements, significant spatial correlation of the secondarily formed aerosols with ozone and formaldehyde is found in the afternoon. 相似文献
616.
Jens Fölster Cecilia Andrén Kevin Bishop Ishi Buffam Neil Cory Willem Goedkoop Kerstin Holmgren Richard Johnson Hjalmar Laudon Anders Wilander 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):331-338
The recovery from acidification has led to the demand for more precise criteria for classification of acidification. The Swedish Environmental Protection Agency has revised Sweden’s Ecological Quality Criteria for acidification to improve the correlation between the chemical acidification criteria and biological effects. This paper summarises the most relevant findings from several of the studies commissioned for this revision. The studies included data on water chemistry in 74 reference lakes in southern Sweden with data on fish in 61 of the lakes, as well as data on littoral fauna in 48 lakes. We found that the acidity variable most strongly correlated to the biota was the median pH from the current year. Our results probably do not reflect the mechanisms behind the negative effects of acidity on the biota, but are fully relevant for evaluation of monitoring data. The biogeochemical models used for predicting acidification reference conditions generate a pre-industrial buffering capacity. In order to get an ecologically more relevant criteria for acidification based on pH, we transferred the estimated change in buffering capacity into a corresponding change in pH. A change of 0.4 units was defined as the threshold for acidification. With this criterion a considerably lower number of Swedish lakes were classified as acidified when compared with the present Ecological Quality Criteria. 相似文献
617.
André Felipe Simões Debora Cynamon Kligerman Emilio Lèbre La Rovere Maria Regina Maroun Martha Barata Martin Obermaier 《Environmental Science & Policy》2010,13(8):801-808
Climate change is one of the main challenges faced by mankind in this century. Although developing countries have little historical responsibility for climate change, they are likely to be most affected by it since they lack resources to cope with or to adapt to its effects. Studies show that the semi-arid northeast region of Brazil – where the country's poorest populations are concentrated – is one of the most vulnerable to climate change and thus likely to suffer its impacts more severely. The present paper addresses these problems by presenting a concrete initiative for strengthening adaptive capacity in the rural community of Pintadas as a first step in the development of a comprehensive methodology to help smallholder farmers in the region adapt to climate change. Based on the project results this paper highlights the integration of development, adaptive capacity and adaptation strategies. Furthermore, the necessity of vulnerability studies and concrete local experiences is highlighted in order to develop adaptation strategies that can alleviate poverty and minimize climate change impacts for the poor. 相似文献
618.
Sustainable fishing gear: the case of modified circle hooks in a Costa Rican longline fishery 总被引:1,自引:0,他引:1
Yonat Swimmer Jenny Suter Randall Arauz Keith Bigelow Andr��s L��pez Ilena Zanela Alan Bola?os Jorge Ballestero Ra��l Su��rez John Wang Christofer Boggs 《Marine Biology》2011,158(4):757-767
Our research aims to identify longline fishing gear modifications that can improve fishing selectivity and reduce incidental capture of non-target species. Catch rates and anatomical hook locations (AHL) were compared when using a 14/0 standard ??control?? circle hook with a 0° offset and an experimental ??appendage?? hook in a Costa Rican longline fishery. With the appendage, the maximum dimension of the appendage hook was increased by 10% and the minimum dimension of the hook by 19%. A total of 1,811 marine animals were captured during five fishing trips. By taxonomic groups, sea turtles represented the largest total catch (27%), followed by sharks (26%), rays (25%), mahimahi (Coryphaena hippurus) (12%), and tunas and billfish (10%). Non-target and discard species, such as rays and sea turtles, accounted for over half of the total catch. Catch per unit effort (CPUE; number of individuals per 1,000 hooks) was higher with control hooks compared to appendage hooks for all species?? categories except rays; appendage hooks caught 52% fewer sea turtles and 23% fewer tunas and billfish than standard hooks, which represents a significant reduction in bycatch of endangered and other species. No differences were found in the AHL for sea turtles, suggesting use of the appendage may not incur additional advantages regarding turtles?? post-release survivorship. Despite lower catch rates for marketable species, such as sharks and mahimahi, use of the appendage resulted in dramatic reductions in catch rates of sea turtles. The results suggest that large scale adoption of hooks with a significantly wider hook dimension could be an effective conservation measure to maintain marine biodiversity while allowing for continued fishing. 相似文献
619.
Verónica Fuentes Ilka Straehler-Pohl Dacha Atienza Ignacio Franco Uxue Tilves Miriam Gentile Melissa Acevedo Alejandro Olariaga Josep-Maria Gili 《Marine Biology》2011,158(10):2247-2266
Rhizostoma pulmo is one of the most abundant scyphomedusae along the Mediterranean coasts. To understand changes in the population densities
of the medusa stage and its relationship with the benthic stage, we describe all developmental stages from the life cycle
of R. pulmo, from the scyphistoma stage to young medusae reared in the laboratory. Mature scyphistomae showed a mean total body length
of 1.7 mm and the average tentacle number was 16. Asexual reproduction occurred by lateral budding, podocyst and pedalocyst
production. Each strobila released up to 8 ephyrae that had a mean total body diameter of 3.5 mm. Moreover, we also present
data on the temporal and spatial distribution of the species in the Catalan Sea and the coastal lagoon on Mar Menor (NW Mediterranean)
during the years 2007–2009. In the Catalan Sea, the presence of adult R. pulmo was recorded as extended along the whole coast, but most of the observation was concentrated in the central area; the highest
abundances were recorded during the months of July and August. The highest number of observations was detected in 2008 in
coincidence with the inter-annual variation observed in the Mar Menor lagoon. 相似文献
620.
Schmidt G Pesch R Schröder W Conrad A Kolossa-Gehring M Feigenspan S Dobler L Wiesmüller GA Birke M Utermann J 《Environmental geochemistry and health》2011,33(4):399-408
This study aimed at statistically investigating the association between the internal exposure of children and young adults
to uranium (U) and epidemiologically relevant external determinants of exposure. The investigation was performed with data
from two studies within the framework of the German health-related environmental monitoring program: The German Environmental Survey for Children (GerES IV) conducted by the Federal Environment Agency (Umweltbundesamt) with data on 1,780 children 3–14 years of age and their home environment and the German Environmental Specimen Bank (ESB, section: human specimens) with data on 2,253 students 20–29 years of age. Both studies provided data on the U levels in human urine for all probands.
GerES IV furthermore provided an extensive environmental and demographic database on, e.g., U levels in drinking water. The
data from GerES IV and ESB were linked by GIS to spatially relevant exposure information, including background values of U
in stream sediments and in upper and lower soils, U levels in mosses and particulate matter in the lower atmosphere, precipitation
and elevation as well as forest density. Bivariate correlation analysis and two decision tree models showed moderate but significant
associations between U in human urine and U levels in drinking water, stream sediments and upper and lower soils. Future investigations
considering additional epidemiologically relevant data sets may differentiate the results. Furthermore, the sample design
of future environmental epidemiology studies should take the spatial evaluation of the data into greater account. 相似文献