排序方式: 共有27条查询结果,搜索用时 31 毫秒
21.
Deloge-Abarkan M Ha TL Robine E Zmirou-Navier D Mathieu L 《Journal of environmental monitoring : JEM》2007,9(1):91-97
Aerosols of water contaminated with Legionella bacteria constitute the only mode of exposure for humans. However, the prevention strategy against this pathogenic bacteria risk is managed through the survey of water contamination. No relationship linked the Legionella bacteria water concentration and their airborne abundance. Therefore, new approaches in the field of the metrological aspects of Legionella bioaerosols are required. This study was aimed at testing the main principles for bioaerosol collection (solid impaction, liquid impingement and filtration) and the in situ hybridization (FISH) method, both in laboratory and field assays, with the intention of applying such methodologies for airborne Legionella bacteria detection while showering. An aerosolization chamber was developed to generate controlled and reproducible L. pneumophila aerosols. This tool allowed the identification of the liquid impingement method as the most appropriate one for collecting airborne Legionella bacteria. The culturable fraction of airborne L. pneumophila recovered with the liquid impingement principle was 4 and 700 times higher compared to the impaction and filtration techniques, respectively. Moreover, the concentrations of airborne L. pneumophila in the impinger fluid were on average 7.0 x 10(5) FISH-cells m(-3) air with the fluorescent in situ hybridization (FISH) method versus 9.0 x 10(4) CFU m(-3) air with the culture method. These results, recorded under well-controlled conditions, were confirmed during the field experiments performed on aerosols generated by hot water showers in health institutions. This new approach may provide a more accurate characterization of aerobiocontamination by Legionella bacteria. 相似文献
22.
Peter Hopkinson Peter James Anthony Sammut 《Journal of Environmental Planning and Management》2000,43(6):873-895
The appropriate means of benchmarking environmental performance within and between companies is a matter of considerable debate and raises issues such as what information to compare and the reliability and consistency of data. Comparing environmental performance through company environment reports is an approach which has been widely used but, as this paper shows, is difficult and has severe limitations. This paper presents a unique analysis, based on the UK water industry, which compares data reported in company environmental reports and data on the same companies reported through the industry regulators. In turn, this is compared with the environmental performance indicators proposed by two other systems, one advanced by the UK water industry itself. The results demonstrate the difficulty of specifying environmental indicators that enable meaningful comparison. The difficulty of comparing environmental performance in a sector with a comprehensive approach to, and long history of, environmental performance reporting presents some hard lessons for other sectors. 相似文献
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24.
Magali?Combes David?Pinaud Christophe?Barbraud Jacques?Trotignon Fran?ois?BrischouxEmail author 《Die Naturwissenschaften》2018,105(1-2):5
Severe population declines of amphibians have been shown to be attributed to climate change. Nevertheless, the various mechanisms through which climate can influence population dynamics of amphibians remain to be assessed, notably to disentangle the relative synergetic or antagonistic influences of temperature and precipitations on specific life history stages. We investigated the impact of rainfall and temperature on the egg-clutch abundance in a population of agile frog (Rana dalmatina) during 29 years (1987–2016) on 14 breeding sites located in Brenne Natural Park, France. Specifically, we examined the influence of environmental conditions occurring during five temporal windows of the year cycle corresponding to specific life history stages. Overall, our results suggest that the year-to-year fluctuations of egg-clutch abundances in Brenne Natural Park were partly dependent on local climatic conditions (rainfall and temperature). Climate seemed to influence breeding frogs during the autumn-winter period preceding reproduction. Spring and summer conditions did not influence reproduction. Additionally, we failed to detect effects of climatic conditions on newly metamorphosed individuals. Other factors such as density dependence and inter-specific interactions with introduced predators are likely to play a significant role in reproduction dynamics of the studied frog populations. 相似文献
25.
Martine Hossaert-McKey Catherine Soler Bertrand Schatz Magali Proffit 《Chemoecology》2010,20(2):75-88
Mutualisms are interspecies interactions in which each participant gains net benefits from interacting with its partner. In
nursery pollination mutualisms, pollinators reproduce within the inflorescence they pollinate. In these systems, each partner
depends directly on the other for its reproduction. Therefore, the signal responsible for partner encounter is crucial in
these horizontally transmitted mutualisms, in which the association between specific partners must be renewed at each generation.
As in many other interspecies interactions, chemical signals are suspected to be important in the functioning of these mutualisms.
We synthesized and compared the published data available on the role of floral scents in the functioning of the 16 known independently
evolved nursery pollination mutualisms. So far, attraction of pollinators to their specific hosts has been investigated in
only seven of these systems, and the majority of the studies have been conducted on one of them, fig/fig wasp interactions.
While such unevenness of the information limits the potential for meta-analysis, some patterns emerge from this review concerning
the role of flower volatiles in maintaining the specificity of pollinator attraction, in signaling the appropriate phenological
stage for pollinator visit, in attracting the pollinator toward the rewardless sex in dioecious plant species and in aiding
the location and exploitation of resources by parasites and predators associated with these mutualisms. Finally, we highlight
new perspectives on the evolution of signals in these diversified systems depending on the age and the degree of specificity
of the interaction, and on the effect of phylogenetic inertia on the evolutionary dynamics of plant signals. 相似文献
26.
Magali Lago Ana Aguiar André Natário Carla Fernandes Miguel Faria Eugénia Pinto 《Environmental monitoring and assessment》2014,186(9):5581-5593
This study assessed if the use of sterol demethylase inhibitor fungicides in vineyard production can induce resistance to azoles in Aspergillus strains and if it can induce selection of resistant species. We also tried to identify the Aspergillus species most prevalent in the vineyards. Two vineyards from northern Portugal were selected from “Vinhos Verdes” and “Douro” regions. The vineyards were divided into plots that were treated or not with penconazole (PEN). In each vineyard, air, soil, and plant samples were collected at three different times. The strains of Aspergillus spp. were isolated and identified by morphological and molecular techniques. We identified 46 Aspergillus section Nigri, eight Aspergillus fumigatus, seven Aspergillus lentulus, four Aspergillus wentii, two Aspergillus flavus, two Aspergillus terreus, one Aspergillus calidoustus, one Aspergillus westerdijkiae, one Aspergillus tamarii, and one Eurotium amstelodami. Aspergillus strains were evaluated for their susceptibility to medical azoles used in human therapy (itraconazole, posaconazole, and voriconazole) and to agricultural azoles (PEN) used in the prevention and treatment of plant diseases. The isolates showed moderate susceptibility to voriconazole. We did not observe any decrease of susceptibility to the medical azoles tested throughout the testing period in any of the treated plots, although some of the resistant species were isolated from there. 相似文献
27.
Gnandi K Musa Bandowe BA Deheyn DD Porrachia M Kersten M Wilcke W 《Journal of environmental monitoring : JEM》2011,13(7):2033-2041
The state of contamination of tropical environments, particularly in Africa, remains a relatively under explored subject. Here, we determined polycyclic aromatic hydrocarbon (PAH) and trace metal concentrations in coastal sediment and biota samples (fish and mussels) from Togo (West Africa). In the sediments, the ∑21 PAH concentrations ranged from <4 ng g(-1) to 257 ng g(-1), averaging 92 ng g(-1). Concentration ratios of low molecular weight PAHs (2-3 rings) versus high molecular weight PAHs (≥4 rings) were always lower than 1 (ranging from 0.08 to 0.46) indicating that high molecular weight PAHs were dominant in all sediment samples, and that PAHs originated mainly from anthropogenic combustion activities. The sediments were also analyzed for major elements and a total of 15 trace metals, which were found in elevated concentrations. The calculated enrichment factor (EF) values relative to the Earth's crust show that the contamination is extremely severe for Cd (EF = 191), severe for Cr (EF = 18) and U (EF = 17.8), moderately severe for Zr (EF = 8.8), for Ni (EF = 6.8), Sr (EF = 5.9) and Ba (EF = 5.4), and moderate for V (EF = 3.6) and Zn (EF = 3.4). Sediments sampled in areas affected by the dumping of phosphorite mine tailings showed particularly high concentrations of trace metals. Overall, concentrations of both PAHs and trace metals in sediment tend to increase from the coastline to the open sea (2 km offshore). This is attributable to the increasingly finer texture of coastal sediment found offshore, which has a terrigenous origin and appears loaded with various contaminants through adsorption processes. Such high loads of trace metals were also found in the biota (fish and mussels). The ratio of measured trace metal concentrations in biota to threshold limits set by the World Health Organization herein defined as relative health factor (RHF) was high. Average RHF values in fish were highest for Se (470), As (250), Ag (97), Ni (78), Mn (63), Fe (53), Pb (36), Cd (10), and Cr (7) while lowest for Cu (0.08) and Zn (0.03). Cd and Al did not bioaccumulate in the analyzed fish species. In mussels, the RHF values were highest for Fe (9,108), As (295), Pb (276), Se (273), Mn (186), Ni (71), Ag (70), Cd (14), and Cu (4). 相似文献