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901.
This paper presents and discusses the method and results of account for material flows in Sweden for the year 2004. The results show that it is possible to compile material flow data from existing sources in the Swedish statistical system. By using the European classification system of goods, the Combined Nomenclature, as the basic unit of the data collection, both data collection and aggregation into material flow categories were made possible. Although these data exist in the statistical system, they are not easily available for the scientific community. This is due to several reasons, such as the aggregation of data in the system of statistics not corresponding to the material flow account structure and the fact that data on import and export of materials are organised differently than data for domestic extraction. Almost 50% of the material flows in Sweden are flows of minerals, mainly construction minerals followed by iron ores. Most of the extracted iron ores are exported. In comparison with other European countries this generates a unique situation with Sweden as the only net exporter of iron ores. The flow of biomass in terms of wood is also considerable (26% of the Swedish material flows in 2004). The domestic material consumption (inflow) per capita in 2004 was 8 tonnes minerals, 6 tonnes biomass and almost 3 tonnes of fossil fuels. Of the material flows of fossil fuels petroleum and natural gas dominates with 90%.  相似文献   
902.
Multicriteria decision support systems are applied in natural resource management in order to clarify the planning process for the stakeholders, to make all available information usable and all objectives manageable. Especially when the public is involved in planning, the decision support system should be easy to comprehend, transparent and fair. Social choice theory has recently been applied to group decision-making in natural resources management to accomplish these objectives. Although voting forms the basis of democracy, and is usually taken as a fair method, the influence of voters over the outcome may vary. It is also possible to vote strategically to improve the results from each stakeholder's point of view. This study examines the use of social choice theory in revealing stakeholders' preferences in participatory forest planning, and the influence of different voters on the outcome. The positional voting rules examined were approval voting and Borda count, but both rules were slightly modified for the purposes of this study. The third rule examined, cumulative rule, resembles utilitarian voting rules. The voting rules were tested in a real participatory forest planning situation in eastern Lapland, Finland. All voting rules resulted in a different joint order of importance of the criteria. Yet, the preference orders produced had also a lot in common and the criteria could be divided into three quite distinct groups according to their importance. The influence of individual voters varied between the voting rules, and in each case different voter was the most influential.  相似文献   
903.
Previous research addressing the unequal distribution of locally desirable land (LDL) has mainly ignored their associated environments (i.e., rural or urban). However, this study proposed a new framework that treats rural and urban regions separately. In rural areas, the LDLs included all public lands. In urbanized areas, the LDLs were defined as green open spaces. Potential inequities in the distribution of LDL were assessed with respect to socioeconomic characteristics of residents in the State of Georgia. Using US Census Bureau Data (2000), Census Block Groups (CBGs) adjacent to LDLs were compared to CBGs outside of LDLs on four socioeconomic variables (per capita income, occupation, education, and race) in urban, suburban and rural environments. Results showed that CBGs adjacent to LDLs were composed of statistically significant upper-class communities containing fewer blue-collar workers, more whites, and higher income and higher educated people in rural, suburban and urban areas.  相似文献   
904.
A simple model predicting bathing water concentrations of Escherichia coli from livestock in the Irvine catchment in SW Scotland has been adapted for intestinal enterococci (IE). This has been used to predict risk of bather illness by extrapolation of published data on bather IE exposure vs incidence of gastro-enteritis. Simulated reduction in the risk of illness by reduced faecal loading was multiplied by a willingness to pay for risk reduction to estimate the annual benefits of mitigation. Health benefits of reducing loading by 75% at Irvine Beach were estimated by a willingness to pay method to be about pound 276k pa. Estimated annualised costs of diffuse pollution mitigation measures across the catchment were higher (> pound 1m), and it is very unlikely that 75% mitigation is achievable with current stocking rates. Further work should explore the influence of uncertainty of model parameters, and use emerging epidemiological information on specific zoonotic pathogens such as E. coli O157 and Cryptosporidium. Other components of the value of clean water should also be included to obtain a complete estimate of the cost:benefit of mitigation.  相似文献   
905.
906.
A novel approach to predict aquatic toxicity from molecular structure   总被引:1,自引:0,他引:1  
The main aim of the study was to develop quantitative structure-activity relationship (QSAR) models for the prediction of aquatic toxicity using atom-based non-stochastic and stochastic linear indices. The used dataset consist of 392 benzene derivatives, separated into training and test sets, for which toxicity data to the ciliate Tetrahymena pyriformis were available. Using multiple linear regression, two statistically significant QSAR models were obtained with non-stochastic (R2=0.791 and s=0.344) and stochastic (R2=0.799 and s=0.343) linear indices. A leave-one-out (LOO) cross-validation procedure was carried out achieving values of q2=0.781 (scv=0.348) and q2=0.786 (scv=0.350), respectively. In addition, a validation through an external test set was performed, which yields significant values of Rpred2 of 0.762 and 0.797. A brief study of the influence of the statistical outliers in QSAR's model development was also carried out. Finally, our method was compared with other approaches implemented in the Dragon software achieving better results. The non-stochastic and stochastic linear indices appear to provide an interesting alternative to costly and time-consuming experiments for determining toxicity.  相似文献   
907.
Edwards C  Graham D  Fowler N  Lawton LA 《Chemosphere》2008,73(8):1315-1321
Microcystin-LR (MC-LR) was readily biodegraded on addition to six different water samples irrespective of their previous exposure to microcystins. Subsequent studies with water from three of these water bodies confirmed the degradation of MC-LR and also demonstrated the biodegradation of MC-LF, nodularin and mixture of microcystins and nodularin. Rates of degradation of MC-LR, MC-LF and NOD in individual water samples ranged from a half-life of 4 to 18d. Analysis by HPLC-PDA-ESI+ and MALDI MS/MS revealed novel intermediate degradation products of MC-LF and nodularin which included demethylation, hydrolysis, decarboxylation and condensation of the parent compound(s). Our study suggests a possible diversity of micro-organisms and/or pathways which has not been previously observed.  相似文献   
908.
Enhancing community-based disaster preparedness with information technology   总被引:1,自引:0,他引:1  
A critical component of community-based disaster preparedness (CBDP) is a local resource database of suppliers providing physical, information and human resources for use in disaster response. Maintenance of such a database can become a collaborative responsibility among community-based non-governmental organisations (NGOs) and public and private community organisations. In addition to mobilising resources, this process raises awareness within the community and aids in assessing local knowledge and resources. This paper presents the results of a pilot study on implementing a community-based resource database through collaboration with local American Red Cross chapters and public and private community organisations. The design of the resource database is described. The resource database is accessible via the internet and offline using laptops and handheld Personal Digital Assistants. The study concludes that CBDP is strengthened through a combination of appropriate information technology and collaborative relationships between NGOs and community-based organisations.  相似文献   
909.
The focus of this paper is on the dynamics of a dense current flowing along the continental slope, and the frictionally induced downward motion it experiences. In particular, the movement of the lateral boundaries where the isopycnals meet the bottom are considered. The current is taken to be wide compared to the Rossby radius, which is in accordance with observations and makes the dynamics quasigeostrophic. The time development of the plume thickness is studied, using three different parameterisations for the bottom friction.Independently of the choice of parameterisation, the following results are obtained: In the central part of the plume friction acts as a diffusive process to minimise the curvature of the upper surface of the plume. At the upper edge the plume quickly approaches a state with small slope, i.e. small geostrophic velocity and small frictionally induced downward flow. At the lower edge a tongue of dense water shoots out creating a widening layer. The thickness of the migrating layer is approximately equal to the boundary layer depth and its downward speed is comparable to the along-slope geostrophic velocity. The downslope end of the migrating layer may form a steep front which requires some precautions in the numerical procedure.  相似文献   
910.
The strong fluctuating component in the measured concentration time series of a dispersing gaseous pollutant in the atmospheric boundary layer, and the hazard level associated to short-term concentration levels, demonstrate the necessity of calculating the magnitude of turbulent fluctuations of concentration using computational simulation models. Moreover the computation of concentration fluctuations in cases of dispersion in realistic situations, such as built-up areas or street canyons, is of special practical interest for hazard assessment purposes. In this paper, the formulation and evaluation of a model for concentration fluctuations, based on a transport equation, are presented. The model is applicable in cases of complex geometry. It is included in the framework of a computational code, developed for simulating the dispersion of buoyant pollutants over complex geometries. The experimental data used for the model evaluation concerned the dispersion of a passive gas in a street canyon between 4 identical rectangular buildings performed in a wind tunnel. The experimental concentration fluctuations data have been derived from measured high frequency concentrations. The concentration fluctuations model is evaluated by comparing the model's predictions with the observations in the form of scatter plots, quantile-quantile plots, contour plots and statistical indices as the fractional bias, the geometrical mean variance and the factor-of-two percentage. From the above comparisons it is concluded that the overall model performance in the present complex geometry case is satisfactory. The discrepancies between model predictions and observations are attributed to inaccuracies in prescribing the actual wind tunnel boundary conditions to the computational code.  相似文献   
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