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71.
The aim was to investigate occupational exposure to electric and magnetic fields during tasks at ground or floor level at 110?kV substations in Finland and to compare the measured values to Directive 2013/35/EU. Altogether, 347 electric field measurements and 100 magnetic field measurements were performed. The average value of all electric fields was 2.3?kV/m (maximum 6.4?kV/m) and that of magnetic fields was 5.8?µT (maximum 51.0?µT). It can be concluded that the electric and magnetic field exposure at ground or floor level is typically below the low action levels of Directive 2013/35/EU. The transposition of the directive will not create new needs to modify the work practice of the evaluated tasks, which can continue to be performed as before. However, for workers with medical implants, the exposure may be high enough to cause interference.  相似文献   
72.
Globally, yam (Dioscorea spp.) is the fifth most important root crop after sweet potatoes (Ipomoea batatas L.) and the second most important crop in Africa in terms of production after cassava (Manihot esculenta L.) and has long been vital to food security in sub-Saharan Africa (SSA). Climate change is expected to have its most severe impact on crops in food insecure regions, yet very little is known about impact of climate change on yam productivity. Therefore, we try estimating the effect of climate change on the yam (variety: Florido) yield and evaluating different adaptation strategies to mitigate its effect. Three regional climate models REgional MOdel (REMO), Swedish Meteorological and Hydrological Institute Regional Climate Model (SMHIRCA), and Hadley Regional Model (HADRM3P) were coupled to a crop growth simulation model namely Environmental Policy Integrated Climate (EPIC) version 3060 to simulate current and future yam yields in the Upper Ouémé basin (Benin Republic). For the future, substantial yield decreases were estimated varying according to the climate scenario. We explored the advantages of specific adaptation strategies suggesting that changing sowing date may be ineffective in counteracting adverse climatic effects. Late maturing cultivars could be effective in offsetting the adverse impacts. Whereas, by coupling irrigation and fertilizer application with late maturing cultivars, highest increase in the yam productivity could be realized which accounted up to 49 % depending upon the projection of the scenarios analyzed.  相似文献   
73.
Abstract

The herbicide Basalin [Fluchloralin: N‐propyl‐N (2 chloroethyl) ‐2,6—dinitro‐n‐trifluoromethyl aniline] was found to reduce the germination percentage in both Helianthus annuus L. and Linum usitatissimum L.. Treatment with Basalin also decreased the mitotic index and increased the total chromosomal abnormalities in these crops. Chromosomal abnormalities arising due to mitotic spindle disruption were commonly observed.  相似文献   
74.
A study of gas-phase mercury speciation using detailed chemical kinetics.   总被引:5,自引:0,他引:5  
Mercury speciation in combustion-generated flue gas was modeled using a detailed chemical mechanism consisting of 60 reactions and 21 species. This speciation model accounts for the chlorination and oxidation of key flue-gas components, including elemental mercury (Hg0). Results indicated that the performance of the model is very sensitive to temperature. Starting with pure HCl, for lower reactor temperatures (less than approximately 630 degrees C), the model produced only trace amounts of atomic and molecular chlorine (Cl and Cl2), leading to a drastic underprediction of Hg chlorination compared with experimental data. For higher reactor temperatures, model predictions were in good accord with experimental data. For conditions that produce an excess of Cl and Cl2 relative to Hg, chlorination of Hg is determined by the competing influences of the initiation step, Hg + Cl = HgCl, and the Cl recombination reaction, 2Cl = Cl2. If the Cl recombination reaction is faster, Hg chlorination will eventually be dictated by the slower pathway Hg + Cl2 = HgCl2.  相似文献   
75.
In this study, the prevalence of different enteric viruses in commercial mussels was evaluated at the retail level in three European countries (Finland, Greece and Spain). A total of 153 mussel samples from different origins were analysed for human norovirus (NoV) genogroups I and II, hepatitis A virus (HAV) and hepatitis E virus (HEV). Human adenovirus (HAdV) was also tested as an indicator of human faecal contamination. A full set of controls (such as sample process control, internal amplification controls, and positive and negative controls) were implemented during the process. The use of a sample process control allowed us to calculate the efficiencies of extraction, which ranged from 79 to 0.5?%, with an average value of 10?%. Samples were positive in 41?% of cases, with HAdV being the most prevalent virus detected (36?%), but no significant correlation was found between the presence of HAdV and human NoV, HAV and HEV. The prevalences of human norovirus genogroup II, HEV and human NoV genogroup I were 16, 3 and 0.7?%, respectively, and HAV was not detected. The estimated number of PCR detectable units varied between 24 and 1.4?×?103?g?1 of digestive tract. Interestingly, there appeared to be a significant association between the type of mussel species (M. galloprovincialis) and the positive result of samples, although a complete overlap between country and species examined required this finding to be confirmed including samples of both species from all possible countries of origin.  相似文献   
76.
The effects of long-term enhanced UV-B radiation on growth and secondary compounds of two conifer species were studied in an outdoor experiment. Scots pine (Pinus sylvestris) seedlings were exposed for two growing seasons and Norway spruce (Picea abies) seedlings for three growing seasons to supplemental UV-B radiation, corresponding to a 30% increase in ambient UV-B radiation. The experiment also included appropriate controls for ambient and increased UV-A radiation. Enhanced UV-B did not affect the growth of the conifer seedlings. In addition, neither the concentrations of terpenes and phenolics in the needles nor the concentrations of terpenes in the wood were affected. However, in the UV-A control treatment the concentrations of diterpenes in the wood of Scots pine decreased significantly compared to the ambient control. Apparently, a small increase in UV-B radiation has no significant effects on the secondary compounds and growth of Scots pine and Norway spruce seedlings.  相似文献   
77.
Lawton et al. (1998) found, in a highly cited study, that the species richness of 8 taxa each responds differently to anthropogenic disturbance in Cameroon forests. Recent developments in conservation science suggest that net number of species is an insensitive measure of change and that understanding which species are affected by disturbance is more important. It is also recognized that all disturbance types are not equal in their effect on species and that grouping species according to function rather than taxonomy is more informative of responses of biodiversity to change. In a reanalysis of most of the original Cameroon data set (canopy and ground ants, termites, canopy beetles, nematodes, and butterflies), we focused on changes in species and functional composition rather than richness and used a more inclusive measure of forest disturbance based on 4 component drivers of change: years since disturbance, tree cover, soil compaction, and degree of tree removal. Effects of disturbance on compositional change were largely concordant between taxa. Contrary to Lawton et al.’s findings, species richness for most groups did not decline with disturbance level, providing support for the view that trends in species richness at local scales do not reflect the resilience of ecosystems to disturbance. Disturbance affected species composition more strongly than species richness for butterflies, canopy beetles, and litter ants. For these groups, disturbance caused species replacements rather than just species loss. Only termites showed effects of disturbance on species richness but not composition, indicating species loss without replacement. Although disturbance generally caused changes in composition, the strength of this relationship depended on the disturbance driver. Butterflies, litter ants, and nematodes were correlated with amount of tree cover, canopy beetles were most strongly correlated with time since disturbance, and termites were most strongly correlated with degree of soil disturbance. There were moderately divergent responses to disturbance between functional feeding groups. Disturbance was most strongly correlated with compositional differences of herbivores within beetles and nematodes and humus feeders within termites. Our results suggest that consideration of the impact of different forms of disturbance on species and functional composition, rather than on net numbers of species, is important when assessing the impacts of disturbance on biodiversity.  相似文献   
78.
Polymeric materials are combustible in nature and poly (vtnyl chloride) is no ex-ception. Due to its high chlorine contents it is relatively fiame retardant, hawever be-cause of the processing aids such as plasttcizer etc. this advantage is lost. Duringburning the two main hazards of PVC are Hydrogen Chloride gas and copiousamount of smoke. Dtfferent methods for smoke suppression of polymers are also ap-plicable to the case of PVC. Complexes of dzfferent metal, mixedmetals and metalbased organics are discussed along with other methods of smoke suppression in PVC.Some aspects of smoke measurement have also been covered.  相似文献   
79.
The waste slurry generated in fertilizer plants in India has been converted into a cheap carbonaceous adsorbent material. The prepared adsorbent has been characterised and used for the removal of lead and chromium metals. The kinetics of adsorption and the extent of adsorption at equilibrium are dependent on the physical and chemical characteristics of the adsorbate, adsorbent and experimental system. Results of laboratory scale studies conducted to delineate the effect of such parameters on the kinetics of adsorption of metal ions are reported. Parameters evaluated include: hydronium ion concentration, temperature, initial adsorbate concentration, size of adsorbent, and amount of adsorbent. On the basis of these studies the various physical parameters such as effective diffusion coefficient, activation energies and entropy of activation are evaluated, as these provide some information regarding the mechanistic aspects. Mass transfer coefficient values suggest a rapid transport of the adsorbate from bulk to solid phase.  相似文献   
80.
This article is a primer on the emerging role for Information Technology (IT) in the Environmental Justice (EJ) movement. It explores current and potential uses of IT by EJ organisations fighting to protect vulnerable local environments and it addresses some of the barriers to more widespread movement efficacy via e-advocacy. We argue a chief but not insurmountable barrier is the disproportionate access to, and knowledge of, the benefits of using IT in the struggle for equitable decisions about environmental impacts.  相似文献   
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