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61.
Environmental Geochemistry and Health - Several essential nutrients such as Fe, Co, Cu, I, Se, and Zn are vital to grazing cattle as they play a significant role in intracellular enzyme systems,...  相似文献   
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In heterogeneous environments, differential niche selection by two competing species will result in niche partitioning so that individuals of each species can maximise their fitness under different sets of environmental variables. Thus, niche partitioning is considered essential to allow co-existence of ecologically related species. To assess whether niche partitioning was occurring between native red squirrels and alien grey squirrels living together in a 13-ha high-quality mixed deciduous woodland in north Italy, we investigated temporal and spatial patterns in their activity and foraging behaviour between 1996 and 1998. We used live trapping and radio-tracking to study numbers, distribution and behaviour of squirrels. Daily and seasonal temporal activity patterns, and activity on the ground and in the trees, were similar in the two species. However, grey squirrels were more tree specialists and had a narrower tree-species niche width than red squirrels, in particular making greater use of oak. Other studies of red and grey squirrels in allopatry show that the two species differ in the extent they utilise oak. Overall, tree-species niche overlap was about 70%. Grey squirrels had larger home ranges than red squirrels. Home ranges and core areas of both species were larger in males than females. Also, intraspecific home range and core-area overlap patterns were similar to those found in allopatric populations of these species. Overall, there was no evidence that the use of space of one species was affected by the other. Our results show that there was no niche partitioning of activity or foraging behaviour in time or space during the study. This suggests that, at moderate grey-squirrel densities, red squirrels are unable to avoid competition with grey squirrels, and that competition for food and/or space will occur when these resources become limiting.  相似文献   
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The increase in the use of satellite‐derived precipitation products generated by different methods and algorithms emphasizes the need for a deeper analysis of their quality and accuracy. Using the contingency table method, we evaluated the accuracy of versions 6 and 7 of the Tropical Rainfall Measuring Mission Precipitation (TRMM) 3B42 product in southern Brazil by comparing daily precipitation over 13 years (V6 was tested for historical context). The interpolated data from 25 rain gauges were compared with both versions of TRMM. The V7 product tended to produce a slight increase in PC (proportion correct). V7 also showed a slight increase in the correlation coefficient (CC) and a significant increase in the H (hit rate) and CSI (critical success) indexes. However, the upgraded version shows an undesirable increase in the false alarm ratio. When the rainfall volumes were compared, V6 clearly underestimated the total rainfall over the entire period, but the V7 product slightly overestimated the cumulative volume (11%) which still represented a more reliable estimate than from V6. Furthermore, the main improvement in V7 was a large increase in the quantitative recognition of extreme precipitation events: V6 detected only 1% of the daily rainfalls above 60 mm, whereas V7 detected 57% of the events.  相似文献   
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The main purpose of this paper is to use data envelopment analysis (DEA) as a support tool to establish a relative eco-efficiency measure for the different bioethanol transportation modes and to prioritize these different modes according to these figures. From a review of previous studies, we selected a set of attributes to be considered in DEA, and then experts were consulted about the importance of these attributes for this type of analysis in Brazil. To quantify the attributes, we established indicators and submitted them to DEA to evaluate the relative eco-efficiency to each available transportation mode for the case studied. The use of DEA established the guidelines to improve the transportation modes that were not considered 100?% relatively eco-efficient. These improvements could be achieved considering the percentage, reduction or growth for each of the attributes in the selected transportation mode. The proposed approach can help the Brazilian government to develop a plan to improve the bioethanol transportation infrastructure and can be used to propel short-term improvements in the highway transport of bioethanol, which could be useful given the Brazilian transportation context.  相似文献   
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The objective of this research was to develop a mechanistic model for quantifying N2O emissions from activated sludge plants and demonstrate how this may be used to evaluate the effects of process configuration and diurnal loading patterns. The model describes the mechanistic link between the factors recognized to correlate positively with N2O emissions. The primary factors are the presence of ammonia and nitrite accumulation. Low dissolved oxygen concentrations also may be implicated through differential impacts on ammonia-oxidizing bacteria (AOB) versus nitrite-oxidizing bacteria (NOB) activity. Factors promoting N2O emissions at treatment plants are discussed below. The model was applied to data from laboratory and pilot-scale systems. From a practical standpoint, plant configuration (e.g., plug-flow versus complete-mix), influent loading patterns (and peak load), and certain operating strategies (e.g., handling of return streams) are all important in determining N2O emissions.  相似文献   
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Increased reports of contaminants in atmospheric aerosols necessitate the development of exposure systems that can accurately simulate aerosols for research purposes. This study outlines the design, construction, cost, and performance of a simple plexiglass chamber equipped with nozzles for rain and aerosol generation. The chamber occupies approximately 152 cm x 125 cm (height x width) space and can be used to expose six large (625 cm2) plants or twelve smaller (144 cm2) ones. The total cost of the materials used in construction, including nozzles, was less than 700 dollars. Repeated analysis of the quantity and particle size distribution of the simulated aerosol and rain showed them to be highly predictable. By adjusting the volume and/or concentration of the spray, and the position of plants within the chamber, particle sizes typical of environmental aerosols (< or = 20 microm) and rains (0.7 to 1.2 mm) could be applied to experimental plants. This sample, economical system will allow for precise simulations of important aerosols and rain events in the study of their impingement on plants.  相似文献   
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Environment, Development and Sustainability - The increasing mortality of COVID-19 can aggravate soil contamination by metals, harmful to the health of the population, requiring new projects for...  相似文献   
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The Sete Cidades Lake (437 ha) is located in a volcanic crater of São Miguel Island (Azores). The watershed is 1923 ha, and 25% of it is covered with water. Extreme logging and the use of fertilizers in the cattle grazing areas have caused sedimentation and eutrophication of the main water body (Carlson Trophic State Index TSI = 40–50 mesoeutrophy). To deal with the issue, a linear programming model was created to generate efficient land-use scenarios for different amounts of phosphorus release. The model was calibrated for the present situation and then simulated to obtain 29 scenarios. It allowed us to derive parameters for each scenario. Then a multiobjective program was used to derive an acceptable weight for each indicator. The dominant solutions were discovered and discussed with different stakeholders.  相似文献   
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