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排序方式: 共有107条查询结果,搜索用时 31 毫秒
21.
The objective of this study is to define new requirements for a Brazilian regional emergency plan based on the best practices used in countries such as the USA, UK, Canada, Japan and Australia. Therefore, the risk analysis methodologies and emergency frameworks used in these countries will be taken into account and a critical analysis will be carried out in order to customize and apply their best practices to Brazilian case. In addition, other issues will be looked at, such as the number of accidents and environmental impact in some areas, related to environmental sensitivity in order to define the environment reliability of the whole system in a specific area. Currently in Brazil resources are not optimized in an emergency offshore plan, rather company has to implement its own emergency plan without any kind of coordination. Despite the existence of some procedures, there are no national or regional frameworks to coordinate emergency plans in Brazil. 相似文献
22.
Allometric scaling predicts preferences for burned patches in a guild of East African grazers 总被引:1,自引:0,他引:1
The high herbivore diversity in savanna systems has been attributed to the inherent spatial and temporal heterogeneity related to the quantity and quality of food resources. Allometric scaling predicts that smaller-bodied grazers rely on higher quality forage than larger-bodied grazers. We replicated burns at varying scales in an East African savanna and measured visitation by an entire guild of larger grazers ranging in size from hare to elephant. We found a strong negative relationship between burn preference and body mass with foregut fermenters preferring burns to a greater degree than hindgut fermenters. Burns with higher quality forage were preferred more than burns with lower quality forage by small-bodied grazers, while the opposite was true for large-bodied grazers. Our results represent some of the first experimental evidence demonstrating the importance of body size in predicting how large herbivores respond to fire-induced changes in plant quality and quantity. 相似文献
23.
This article sets outs a generalized utility model for the diagnosis and prediction of accidents among the Spanish workforce. Based on observational data classified into a risk–injury contingency table (19 × 19), we have summarized the accident rate of all Spanish companies over an 11-year period (75,19,732 accidents). By using correspondence analysis a structure composed of three axes can be obtained, the combination of which identifies three separate risk and injury groups, which we use as a general Spanish pattern. The relationships of greater affinity or likelihood amongst the risks and injuries identified in the pattern facilitate decision-making at the risk-assessment stage in Spanish companies. Each risk–injury group has its own characteristics, interpretable within the phenomenological framework of the accident.The main advantage of this model is its potential application to any other country and the feasibility of contrasting results from different countries. One limiting factor, however, is that the model currently lacks a common classification frame for risks and injuries which would enhance this contrast. The aim of this model is to automatically manage work-related accidents at a national level. 相似文献
24.
Emilio Chuvieco Sergio Opazo Walter Sione Hector Del Valle Jesús Anaya Carlos Di Bella Isabel Cruz Lilia Manzo Gerardo López Nicolas Mari Federico González-Alonso Fabiano Morelli Alberto Setzer Ivan Csiszar Jon Ander Kanpandegi Aitor Bastarrika Renata Libonati 《Ecological applications》2008,18(1):64-79
This paper presents results of the AQL2004 project, which has been develope within the GOFC-GOLD Latin American network of remote sensing and forest fires (RedLatif). The project intended to obtain monthly burned-land maps of the entire region, from Mexico to Patagonia, using MODIS (moderate-resolution imaging spectroradiometer) reflectance data. The project has been organized in three different phases: acquisition and preprocessing of satellite data; discrimination of burned pixels; and validation of results. In the first phase, input data consisting of 32-day composites of MODIS 500-m reflectance data generated by the Global Land Cover Facility (GLCF) of the University of Maryland (College Park, Maryland, U.S.A.) were collected and processed. The discrimination of burned areas was addressed in two steps: searching for "burned core" pixels using postfire spectral indices and multitemporal change detection and mapping of burned scars using contextual techniques. The validation phase was based on visual analysis of Landsat and CBERS (China-Brazil Earth Resources Satellite) images. Validation of the burned-land category showed an agreement ranging from 30% to 60%, depending on the ecosystem and vegetation species present. The total burned area for the entire year was estimated to be 153 215 km2. The most affected countries in relation to their territory were Cuba, Colombia, Bolivia, and Venezuela. Burned areas were found in most land covers; herbaceous vegetation (savannas and grasslands) presented the highest proportions of burned area, while perennial forest had the lowest proportions. The importance of croplands in the total burned area should be taken with reserve, since this cover presented the highest commission errors. The importance of generating systematic products of burned land areas for different ecological processes is emphasized. 相似文献
25.
Adsorption of carbon dioxide on alkaline modified X zeolites was investigated by temperature programmed desorption (TPD) analysis of these materials previously saturated with CO(2) at 50, 100 and 200 degrees C. Parent X zeolite (in its sodium form) was treated with different sodium and cesium aqueous solutions, using both carbonates and hydroxides as precursors. The resulting materials were characterised by nitrogen physisorption, XRD, and NH(3)-TPD, in order to determine their morphological, crystallographic and chemical properties. Slight desilication phenomena were observed using hydroxides as precursors, whereas the treatment with Cs salts lead to higher crystallinity losses. Several successive adsorption-desorption cycles were carried out in order to check the regenerability of the adsorbents. Cesium-treated zeolites present higher carbon dioxide retention capacities than the sodium treated and than the parent material. When working with these Cs-modified materials, the desorption takes place mainly at temperatures between 250 and 400 degrees C, results of great practical interest, since it allows the use these kinds of materials for adsorption-desorption cycles. The evolution of the retention capacity with temperature is also markedly more positive for Cs-treated zeolite, especially when carbonate is used as the precursor. These materials maintain high retention capacities at 100 degrees C (10mg g(-1)) and even at 200 degrees C (3mg g(-1)), temperatures at which the most of the adsorbents are inactive. 相似文献
26.
Hugh?DrummondEmail author Cristina?Rodríguez Adriana?Vallarino Claudia?Valderrábano Gabriela?Rogel Emilio?Tobón 《Behavioral ecology and sociobiology》2003,53(5):287-296
According to the desperado sibling hypothesis, chicks of obligately siblicidal species kill their junior broodmates as early as possible because junior broodmates face dire ecological prospects and are consequently predisposed to aggressively overthrow elder broodmates by all-out aggression. The agonistic behavior of junior chicks is virtually unknown because they die so young. We investigated the agonistic behavior of hypothetical desperados by fostering junior brown boobies (Sula leucogaster, an obligately siblicidal species) into nests of the blue-footed booby (S. nebouxii, a facultatively siblicidal species) containing an older singleton blue-foot chick. Controls were junior blue-footed boobies fostered into the same situation. Junior brown boobies were 7 times more aggressive than controls and most of them dominated their elder and larger nestmates. Four of nine brown booby juniors showed relentless aggression, delivering up to 711 pecks, bites and pushes (including "expulsion pushes") per hour, thereby overwhelming nestmates 90% heavier and permanently expelling one of them from the nest. Similarly, in natural broods of two surviving brown booby chicks, the losing chick was 13 times as aggressive as blue-foot subordinates, up to at least age 7 weeks. Contrast of the two species of booby suggests the evolution of agonistic roles within broods may be partly driven by selection on potential victims to express a level and type of aggressiveness appropriate to their status-related ecological prospects. 相似文献
27.
Kuhn Felipe Gustavo Berghahn Emilio Marder Munique Konrad Odorico Sperotto Raul Antonio Granada Camille Eichelberger 《Journal of Material Cycles and Waste Management》2021,23(2):717-726
Journal of Material Cycles and Waste Management - Hulls are considered residues from rice production, and due to its low commercial value, there is little interest in developing biotechnological... 相似文献
28.
Ozone uptake was studied in a pine forest in Tenerife, Canary Islands, an ecotone with strong seasonal changes in climate. Ambient ozone concentration showed a pronounced seasonal course with high concentrations during the dry and warm period and low concentrations during the wet and cold season. Ozone uptake by contrast showed no clear seasonal trend. This is because canopy conductance significantly decreased with soil water availability and vapour pressure deficit. Mean daily ozone uptake averaged 1.9 nmol m(-2) s(-1) during the wet and cold season, and 1.5 nmol m(-2) s(-1) during the warm and dry period. The corresponding daily mean ambient ozone concentrations were 42 and 51 nl l(-1), respectively. Thus we conclude that in Mediterranean type forest ecosystems the flux based approach is more capable for risk assessment than an external, concentration based approach. 相似文献
29.
30.
Moreno B Vivas A Nogales R Macci C Masciandaro G Benitez E 《Environmental science and pollution research international》2009,16(3):253-264
Background, aim, and scope In this work, the potential for using olive-mill solid waste as an organic amendment for biochemical and biological restoration
of a trichloroethylene-contaminated soil, which has previously been stabilized through vermicomposting processes, has been
explored.
Materials and methods Trichloroethylene-contaminated water was pumped into soil columns with a layer of vermicompost at 10-cm depth (biobarrier
system). The impacts of the trichloroethylene on the microbial community were evaluated by determining: (1) the overall microbial
activity (estimated as dehydrogenase activity) and enzyme activities related to the main nutrient cycles (β-glucosidase, o-diphenoloxidase, phosphatase, urease, and arylsulphatase activities). In addition, isoelectric focusing of the soil extracellular
humic-β-glucosidase complexes was performed to study the enzymatically active humic matter related to the soil carbon cycle.
(2) The soil bacterial diversity and the molecular mechanisms for the bacterial resistance to organic solvents were also determined.
For this, polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) was used to detect changes in bacterial
community structure and PCR-single-strand conformational polymorphism (SSCP) was developed and optimised for detection and
discrimination of the resistance-nodulation-division (RND) genes amplified from the contaminated soils.
Results Vermicompost reduced, with respect to the unamended soil, about 30% of the trichloroethylene leaching during the first month
of the experiment. Trichloroethylene had a marked negative effect on soil dehydrogenase, β-glucosidase, urease, phosphatase,
and arylsulphatase activities. Nevertheless, the vermicompost tended to avoid this toxic effect. Vermicompost also displays
stable humic-β-glucosidase complexes that increased the extracellular activity related to C-cycle in the contaminated soils.
The isoelectric focusing technique showed a more biochemically active humic matter in the soil sampled under the vermicompost.
The behaviour of the three main phyla of bacteria isolated from the DGGE bands was quite different. Bands corresponding to
Actinobacteria disappeared, whereas those affiliated with Proteobacteria remained after the trichloroethylene contamination. The disappeared Actinobacteria became visible in the soil amended with the vermicompost. Bands corresponding to Bacteriodetes appeared only in columns of contaminated soils. In this study, six types of RND proteins were detected by PCR-SSCP in the
natural soil, three in the trichloroethylene-contaminated soil and 7/5 in trichloroethylene-contaminated soil above/below
the vermicompost in the biobarrier columns. Trichloroethylene tended to reduce or eliminate all the clones detected in the
uncontaminated soil, whereas new efflux pumps appeared in the biobarrier columns.
Discussion Although enzymes incorporated into the humic substances of vermicomposted olive wastes are quite stable, trichloroethylene
also inhibited the background levels of the soil extracellular β-glucosidase activity in the amended soils. The decrease was
less severe in the biobarrier system, but in any case, no relation was found between the levels of trichloroethylene in soil
and extracellular β-glucosidase activity, or between the latter and the quantity of humic carbon in soils. The isoelectric
focusing technique was carried out in the humic fraction to determine whether the loss of activity occurred in overall extracellular
β-glucosidase or in that linked to stable humic substances (humic–enzyme complexes). The contaminated soils showed the lower
enzyme activities, whereas contaminated and amended soils presented greater quantity of focalised (and therefore stable) humic
carbon and spectra heterogeneity: very different bands with higher enzyme activities. No clear relationship between trichloroethylene
concentration in soil and diversity of the bacterial population was noted. Similar patterns could be found when the community
structures of bacteria and microbial activity were considered. Since the use of the dehydrogenase assay has been recognised
as a useful indicator of the overall measure of the intensity of microbial metabolism, these results could be attributed to
PCR-DGGE methodology, since the method reveals the presence of dominant populations regardless of their metabolic state. Trichloroethylene
maintained or even increased the number of clones with the DNA encoding for RND proteins, except for the contaminated soil
located above the vermicompost. However, the main effect of trichloroethylene was to modify the structure of the community
in contaminated soils, considering the type of efflux pumps encoded by the DNA extracted from soil bacteria.
Conclusions Trichloroethylene inhibited specific functions in soil and had a clear influence on the structure of the autochthonous bacterial
community. The organic matter released by the vermicomposted olive waste tended to avoid the toxic effect of the contaminant.
Trichloroethylene also inhibited the background levels of the soil extracellular β-glucosidase activity, even when vermicompost
was present. In this case, the effect of the vermicompost was to provide and/or to stimulate the humic-β-glucosidase complexes
located in the soil humic fraction >104, increasing the resistance of the enzyme to the inhibition. The bacterial community from the soil presented significantly
different mechanisms to resistance to solvents (RND proteins) under trichloroethylene conditions. The effect of the vermicompost
was to induce these mechanisms in the autochthonous bacterial community and/or incorporated new bacterial species, able to
grow in a trichloroethylene-contaminated ambient. Coupled biochemical and molecular methodologies are therefore helpful approaches
in assessing the effect of an organic amendment on the biochemical and biological restoration of a trichloroethylene-contaminated
soil.
Recommendations and perspectives Since the main biochemical and biological effects of the organic amendment on the contaminated soil seem to be the incorporation
of biochemically active humic matter, as well as new bacterial species able to grow in a trichloroethylene-contaminated ambient,
isoelectric focusing and PCR-SSCP methodologies should be considered as parts of an integrated approach to determine the success
of a restoration scheme. 相似文献