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991.
Operational air quality models have become an important tool to assist the decision makers in European Environmental Offices at different levels: cities, regional and state. Because of the important advance on computing capabilities during the last few years the possibility of incorporating the complex research and academic mesoscale air quality models under routine operational basis has become a reality. OPANA model is the operational version of the research model ANA (Atmospheric mesoscale Numerical pollution model for regional and urban Areas). This model is a limited area model (mesoscale beta) and the capability to extend the prediction horizon is limited unless proper boundary conditions are provided during long simulations. In this contribution we show how AVN/MRF (NOAA) vertical numerical meteorological soundings are incorporated to the OPANA system by using JAVA technology. This new feature helps to keep the air quality model into medium power workstations and the performance is improved accordingly. This technology avoids running mesoscale models over larger areas (continental scale) to accordingly increase the forecasting temporal horizon.  相似文献   
992.
Novel approach to monitoring of the soil biological quality   总被引:13,自引:0,他引:13  
In this study, a new approach to interpretation of results of the simple microbial biomass and respiration measurements in the soil microbiology is proposed. The principle is based on eight basal and derived microbial parameters, which are standardized and then plotted into sunray plots. The output is visual presentation of one plot for each soil, which makes possible the relative comparison and evaluation of soils in the monitored set. Problems of soil microbiology, such as the lack of benchmarking and reference values, can be avoided by using the proposed method. We found that eight parameters provide enough information for evaluation of the status of the soil microorganisms and, thus, for evaluation of the soil biological quality. The usage of rare parameters (potential respiration PR, ratio of potential and basal respiration PR/BR, biomass-specific potential respiration PR/C(bio), available organic carbon C(ext), and biomass-specific available organic carbon C(ext)/C(bio)) can be recommended, besides classical and well-known parameters (microbial biomass C(bio), basal respiration BR, metabolic coefficient qCO(2)). The combination of basal parameters and derived coefficients can also extend our knowledge about the condition of the soil microorganisms. In monitoring the case studies presented, we observed that soils evaluated to possess good biological quality displayed generally higher values of organic carbon, total nitrogen, clay, and cation exchange capacity. The soils of good biological quality can display higher levels of contaminants. This is probably related with the higher content of organic carbon and clay in these soils.  相似文献   
993.
A study of the effect of the organic loading rate (OLR) on the anaerobic acidogenic fermentation of two-phase olive mill solid residue (OMSR) derived from fruits with a low ripening index was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (35 degrees C). Eight experimental runs were carried out at OLRs of 3.2, 5.6, 7.4, 9.6, 11.0, 12.9, 14.0 and 15.1g T-COD/ld, which were equivalent to hydraulic retention times of 50.0, 28.8, 21.8, 16.9, 14.7, 12.4, 11.5 and 10.7d, respectively. The experimental results obtained demonstrated that the optimum value of OLR for the acidogenic fermentation process was 12.9 g T-COD/ld, for which a maximum production of acetic acid was achieved. It was found that inhibition of the process occurred at OLRs higher than 12.9 g T-COD/ld. This was characterized by a significant decrease in the acetic acid concentration in the effluent and an increase in the concentration of other volatile acids that may affect the methanogenic step. The process inhibition was also characterized by the plateau in the curves of the effluent substrate concentration versus the OLR applied. It was found that a first-order kinetics satisfactorily described the influence of non-acetic acid soluble organic matter concentration (S-COD( *)) on the rate of soluble organic matter conversion to acetic acid (R(S-COD)( *)), and the influence of acetic acid concentration (AcH) on the rate of acetic acid production (R(AcH)), while a potential equation type adequately described the influence of acetic acid concentration on the volumetric hydrogen production (R(ACH) ). The kinetic constant for soluble organic matter removal was 0.145 d(-1), while the constant for acetic acid formation was found to be 0.075 d(-1).  相似文献   
994.
The effects of amendment with municipal solid waste compost (MSWC) and anaerobically digested sewage sludge (SS) on the compositional and structural features of soil humic acids (HAs) were investigated. For this purpose, HAs were isolated from MSWC, SS, and two different Portuguese soils, a sandy Haplic Podzol and a clay loam Calcic Vertisol, which were either unamended or amended with MSWC or SS at a rate of 60tha(-1). The isolated HAs were analyzed for elemental and acidic functional group composition, and by ultraviolet/visible, Fourier transform infrared (FT IR), and fluorescence spectroscopies. The application of MSWC and especially SS to soils determined an increase of C, N, H, and S contents and E(4)/E(6) ratios (i.e., ratios of absorbances at 465 and 665nm), and a decrease of O, COOH, and phenolic OH contents and C/N, C/H, and O/C ratios of soil HAs. The FT IR and fluorescence results showed that the organic amendments, especially SS, caused an increase of the aliphatic character and a decrease of the degrees of aromatic polycondensation, polymerization, and humification of amended soil HAs. Both MSWC and SS affected more markedly the clayey soil HAs than the sandy soil HAs, possibly due to less extended mineralization processes and the protective action of clay minerals on amended soil HAs.  相似文献   
995.
996.
Application of animal manure amendments to agricultural soils is a common practice to improve soil fertility through the addition of essential plant nutrients. This practice may increase the potential for atrazine (2-chloro-4-ethylamino-6-isopropylamino-1, 3, 5-triazine) leaching due to competition for adsorption sites between the pesticide and dissolved organic carbon (DOC) added through manure. We evaluated the influence of liquid cow manure (LCM) application on soil properties, atrazine adsorption, and the physicochemical controlling mechanisms in an Andisol. The LCM was applied at rates equivalent to 0, 100,000, 200,000, and 300,000 L ha(-1), resulting in treatments S-0, S-100, S-200, and S-300, respectively. The LCM application increased DOC and pH of the soils immediately on addition, but pH returned to S-0 values 30 d after application. The LCM application did not modify atrazine adsorption with the two lowest application rates (S-100 and S-200), but atrazine adsorption was decreased in S-300 (K(f) = 0.96) compared with the control (S-0) (K(f) = 1.19), possibly due to the competitive adsorption of DOC with the pesticide. The Fourier-transformed infrared analysis showed that LCM increased aliphaticity and presence of N-containing groups and polysaccharide-like groups in amended soils; however, these properties did not modify the atrazine interaction in the studied amended soils. Interestingly the addition of DOC to soil at the high application rate (S-300) reduced atrazine adsorption in this rich OM Andisol despite the LCM not raising the concentration of stable organic matter. The application of high rates of liquid manure containing DOC incurs an increased risk of pesticide leaching.  相似文献   
997.
Water quality in streams is dependent on landscape metrics at catchment and wetland scales. A study was undertaken to evaluate the correlation between landscape metrics, namely patch density and area, shape, heterogeneity, aggregation, connectivity, land-use ratio, and water quality variables (salinity, nutrients, sediments, alkalinity, other potential pollutants and pH) in the agricultural areas of a semiarid Mediterranean region dominated by irrigated farmlands (NE Spain). The study also aims to develop wetland construction criteria in agricultural catchments. The percentage of arable land and landscape homogeneity (low value of Simpson index) are significantly correlated with salinity (r(2) = 0.72) and NO(3)-N variables (r(2) = 0.49) at catchment scale. The number of stock farms was correlated (Spearman's corr. = 0.60; p < 0.01) with TP concentration in stream water. The relative abundance of wetlands and the aggregation of its patches influence salinity variables at wetland scale (r(2) = 0.59 for Na(+) and K(+) concentrations). The number and aggregation of wetland patches are closely correlated to the landscape complexity of catchments, measured as patch density (r(2) = 0.69), patch size (r(2) = 0.53), and landscape heterogeneity (r(2) = 0.62). These results suggest that more effective results in water quality improvement would be achieved if we acted at both catchment and wetland scales, especially reducing landscape homogeneity and creating numerous wetlands scattered throughout the catchment. A set of guidelines for planners and decision makers is provided for future agricultural developments or to improve existing ones.  相似文献   
998.
Using on-site survey data from Gros Morne National Park in Newfoundland, this paper estimates and compares several truncated count data models of recreation demand. The selected model accounts not only for the truncated and overdispersed nature of the data but also for endogenous stratification due to the oversampling of avid users. Moreover, the model that allows for a flexible specification of the overdispersion parameter dominates on the basis of goodness of fit. The results are used to estimate the users' value of access to the park.  相似文献   
999.
This article analyzes the relationship between the configuration and spatial reorganization of land-use and land-cover in the Pujal-Coy project area, Huasteca Potosina region, eastern San Luis Potosí, Mexico, as well as the relationship between these changes and the environmental conditions prevailing in the area. Land-use and land-cover changes were determined through the analysis and interpretation of satellite images from different dates. The changes identified in the different study periods were correlated with the prevailing physical factors. The results show that the spatial configuration of farming activities, initially induced by the implementation of a regional development project, is highly correlated to the presence of limiting factors such as soil type, slope, and climate. Particularly, the former represents the element that has led to the establishment of the current distribution pattern of farming activities.  相似文献   
1000.
Islands harbor a disproportionate amount of the earth's biodiversity, but a significant portion has been lost due in large part to the impacts of invasive mammals. Fortunately, invasive mammals can be routinely removed from islands, providing a powerful tool to prevent extinctions and restore ecosystems. Given that invasive mammals are still present on more than 80% of the world's major islands groups and remain a premier threat to the earth's biodiversity, it is important to disseminate replicable, scaleable models to eradicate invasive mammals from islands. We report on a successful model from western México during the past decade. A collaborative effort between nongovernmental organizations, academic biologists, Mexican government agencies, and local individuals has resulted in major restoration efforts in three island archipelagos. Forty-two populations of invasive mammals have been eradicated from 26 islands. For a cost of USD 21,615 per colony and USD 49,370 per taxon, 201 seabird colonies and 88 endemic terrestrial taxa have been protected, respectively. These conservation successes are a result of an operational model with three main components: i) a tri-national collaboration that integrates research, prioritization, financing, public education, policy work, capacity building, conservation action, monitoring, and evaluation; ii) proactive and dedicated natural resource management agencies; and iii) effective partnerships with academic researchers in Mexico and the United States. What is now needed is a detailed plan to eradicate invasive mammals from the remaining islands in the region that integrates the needed additional financing, capacity, technical advances, and policy issues. Island conservation in western Mexico provides an effective approach that can be readily applied to other archipelagos where conservation efforts have been limited.  相似文献   
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