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191.
This paper describes how the Carajas iron ore project was set up in February 1985 at a time of deep recession in the iron ore and steel industries. Development of the project was met with much criticism, mainly from North American steel makers, who argued that the project would only be successful through the support of a Third World government, highly dependent on foreign exchange, without any consideration being given to its economic feasibility or to the fundamentals of the market. The authors explain why the World Bank took the step of setting up the project and how its development can be partly explained by the interests of the Japanese and European steel makers. The role of the Brazilian government is explained and the authors conclude that the relatively low rate of investment anticipated by the project will be overshadowed by the high gains in foreign exchange. 相似文献
192.
Ponce de León CA DeNicola K Montes Bayón M Caruso JA 《Journal of environmental monitoring : JEM》2003,5(3):435-440
Different techniques have been employed in order to evaluate the most efficient procedure for the extraction of selenium from soil as required for speciation. Selenium contaminated sediments from Stewart Lake Wetland, California were used. A strong acid mineralization of the samples gives quantitative total selenium, which is then used to estimate recoveries for the milder extraction methods. The different extraction methodologies involve the sequential use of water, buffer (phosphate, pH 7) and either acid solution (e.g. HNO3 or HCl) or basic solutions (e.g. ammonium acetate, NaOH or TMAH). Pyrophosphate extraction was also evaluated and showed that selenium was not associated with humic acids. The extractants were subsequently analyzed by size exclusion chromatography (SEC) with UV (254 and 400 nm) and on-line ICP-MS detection; anion exchange chromatography, and ion-pair reversed phase chromatography with ICP-MS detection. For sequential extractions the extraction efficiencies showed that the basic extractions were more efficient than the acidic. The difference between the acidic and the basic extraction efficiency is carried to the sulfite extraction, suggesting that whatever is not extracted by the acid is subsequently extracted by the sulfite. The species identified with the different chromatographies were selenate, selenite, elemental selenium and some organic selenium. 相似文献
193.
Current methods of estimating potential environmental impacts of metals in hazard and Life Cycle Impact Assessment (LCIA) do not consider differences in chemistry and landscape properties between geographic sites. Here, we developed and applied a model for regional aquatic impact characterization of metals using an updated method for estimating environmental fate factor (FF), bioavailability factor (BF) and aquatic ecotoxicity factor (EF). We applied the model to analyze differences in Comparative Toxicity Potentials (CTPs) of Cu, Ni and Zn for 24 Canadian ecoregions. The combined impacts of regional variability in ambient chemistry (in particular DOC, pH and hardness) and landscape properties (water residence time) can change the CTPs of these metals for freshwater by up to three orders of magnitude and change the relative ranking of metal hazard between ecoregions. Variation among Canadian freshwater chemistries and landscape characteristics influence the FFs within two orders of magnitude, BFs within two orders of magnitude for Ni and Zn and four orders of magnitude for Cu, and EFs within one order of magnitude. Sensitivity of metal FFs to environmental parameters alone spans three orders of magnitude when a constant water chemistry was used for all ecoregions. These results indicate that application of regionalised metal CTPs can have a significant influence in the analysis of ecotoxicological impacts in the life cycle assessment of products and processes. 相似文献
194.
In areas of war and armed conflict it is difficult to get trustworthy and coherent information. Civil society and human rights groups often face problems of dealing with fragmented witness reports, disinformation of war propaganda, and difficult direct access to these areas. Turkish Kurdistan was used as a case study of armed conflict to evaluate the potential use of satellite images for verification of witness reports collected by human rights groups. The Turkish army was reported to be burning forests, fields and villages as a strategy in the conflict against guerrilla uprising. This paper concludes that satellite images are useful to validate witness reports of forest fires. Even though the use of this technology for human rights groups will depend on some feasibility factors such as prices, access and expertise, the images proved to be key for analysis of spatial aspects of conflict and valuable for reconstructing a more trustworthy picture. 相似文献
195.
Axel?HochkirchEmail author Tamara?Mertes Julia?Rautenberg 《Die Naturwissenschaften》2012,99(3):217-224
Biological invasions can affect the structure and function of ecosystems and threaten native plant species. Since most weeds
rely on mutualistic relationships in their new environment, they may act as new competitors for pollinators. Pollinator competition
is likely to be density dependent, but it is often difficult to disentangle competition caused by flower quality from effects
caused by flower quantity. In order to test the effects of the presence and number of flowers of the invasive weed Bunias orientalis on the insect visitation rates in a native species (Sinapis arvensis), we performed two replacement experiments using plants with standardised flower numbers. The visitation rates in S. arvensis were significantly higher than in B. orientalis and the number of insect visits dropped significantly with increasing density of S. arvensis flowers. These results suggest that intraspecific competition among flowers of S. arvensis is stronger than the competitive effect of alien flowers. As flowers of B. orientalis do not seem to distract visitors from S. arvensis, it is unlikely that pollinator competition between these two plant species plays a crucial role. However, it cannot be excluded
that mass blossom stands of B. orientalis may distract flower visitors from native species. 相似文献
196.
Dina A. Salman Saud A. Amer Frank A. Ward 《Journal of the American Water Resources Association》2014,50(5):1208-1225
Climate variability and population growth have intensified the search internationally for measures to adapt to fluctuations in water supplies. An example can be found in the lower part of the transboundary Tigris‐Euphrates Basin where water shortages in 2008‐2009 resulted in high economic costs to irrigation farmers. Losses to irrigators in the lower basin have made a compelling case to identify flexible methods to adapt to water shortage. Few published studies have systematically examined ways to enhance the flexibility of water appropriation systems to adapt to water shortage. This article addresses an ongoing challenge in water governance by examining how profitability at both the farm and basin levels is affected by various water appropriation systems. Four water appropriation systems are compared for impacts on farm income under each of three water supply scenarios. Results show that a (1) proportional sharing of water shortages among provinces and (2) unrestricted water trading rank as the top two appropriation systems. The shadow price of water for irrigation rises from zero at a full water supply level to US$93/1,000 m3 when supply falls to 20% of full levels. Similar methods could be used to analyze challenges facing the design or implementation of water appropriation systems in the world's irrigated regions. 相似文献
197.
Marinka D de Groot Tim Bosch Sandra M Eikhout Peter Vink 《International journal of occupational safety and ergonomics》2005,11(3):331-337
A variety of seals is used to close bags. Each seal has advantages and disadvantages. For shop assistants sealing bags could be a repetitive physically demanding action. Opening and closing the bags again can cause some discomfort or annoyance for consumers. Besides, it is an activity which can endanger safety, i.e., knives being used in opening, children swallowing the systems of sealing. To prevent these problems a new sealing system was developed. In this paper the opinion of shop assistants, consumers and experts on several bag sealing systems was studied. It appeared that for sealing plastic bags, adhesive tape with paper is the best out of 4 systems, closely followed by adhesive tape. It is discussed that for the elderly, there is still room for improvement in opening bag seals. 相似文献
198.
199.
Carlos Alberto A. de Almeida Carla G.B. Brenner Luciane Minetto Carlos A. Mallmann Ayrton F. Martins 《Chemosphere》2013
In this study, an analytical methodology was developed for the determination of psycho-active drugs in the treated effluent of the University Hospital at the Federal University of Santa Maria, RS – Brazil. Samples were collected from point A (Emergency) and point B (General effluent). The adopted methodology included a pre-concentration procedure involving the use of solid phase extraction and determination by liquid chromatography coupled to mass spectrometry. The limit of detection for bromazepam and lorazepam was 4.9 ± 1.0 ng L−1 and, for carbamazepine, clonazepam and diazepam was 6.1 ± 1.5 ng L−1. The limit of quantification was 30.0 ± 1.1 ng L−1, for bromazepam, clonazepam and lorazepam; for carbamazepine was 50.0 ± 1.8 ng L−1 and was 40.0 ± 1.0 ng L−1 for diazepam. The mean concentrations in the Emergency and General effluent treated currents were as follows: for bromazepam, 195 ± 6 ng L−1 and 137 ± 7 ng L−1; for carbamazepine, 590 ± 6 ng L−1 and 461 ± 10 ng L−1; for diazepam, 645 ± 1 ng L−1 and 571 ± 10 ng L−1; for lorazepam, 96 ± 7 ng L−1 and 42 ± 4 ng L−1; and for clonazepam, 134 ± 10 ng L−1 and 57 ± 10 ng L−1. A preliminary risk assessment was conducted: carbamazepine and diazepam require considerable attention owing to their environmental toxicity. The occurrence of these psychoactive-drugs and the environmental risks that they pose demonstrated the need for a more efficient treatment system. As far we are aware, there have been no comparable studies to this on the hazards of hospital effluents in Brazil, and very few that have carried out a risk assessment of psycho-active drugs in hospital effluent in general. 相似文献
200.