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801.
Bart De Smet Laurent Godet Jérôme Fournier Nicolas Desroy Mikaël Jaffré Magda Vincx Marijn Rabaut 《Marine Biology》2013,160(4):751-761
The tube-building polychaete Lanice conchilega can form dense populations, often called reefs, which promote benthic community change and constitute feeding grounds for secondary consumers. The aim of this study was to quantify the role of the L. conchilega reef of the Bay of the Mont Saint-Michel (BMSM) for feeding waders, by combining macrobenthos data, bird counts and bird diet information. Wader densities in the reef were on average 46.6 times higher than in non-reef areas. According to faecal analyses, waders in the reef mainly selected the accompanying fauna and especially crustaceans. The attractiveness of the reef to feeding birds may be largely explained by the high abundance, richness and biomass of macrobenthic species in the reef compared with the rest of the BMSM. 相似文献
802.
Araceli Loredo-Treviño Gerardo Gutiérrez-Sánchez Raúl Rodríguez-Herrera Cristóbal N. Aguilar 《Journal of Polymers and the Environment》2012,20(1):258-265
Plastics are present in a lot of aspects of everyday life. They are very versatile and resistant to microbial attack. Polyurethanes
are used in several industries and are divided in polyester and polyether polyurethanes and there are different types among
them. Despite their microbial resistance, they are susceptible to the attack of fungi and bacteria but the mechanism to elucidate
its biodegradation are unknown. There are reports from bacteria and fungi that are capable of degrading polyurethane but the
studies about the enzymes that attack the plastic are focused on bacterial enzymes only. The enzymes reported are of type
esterase and protease mainly since these enzymes are very unspecific and can recognize some regions in the polyurethane molecule
and hydrolyze it. Fungal enzymes have been studied prior the 1990s decade but recently, some authors report the use of filamentous
fungi to degrade polyurethane and also report some characteristics of the enzymes involved in it. This review approaches polyurethane
biodegradation by focusing on the enzymes reported to date. 相似文献
803.
Mohamed Cissé Didier Montet Gérard Loiseau Marie-Noëlle Ducamp-Collin 《Journal of Polymers and the Environment》2012,20(3):830-837
The individual and interactive effects of glycerol and chitosan concentrations on edible film properties were investigated using response surface methodology. The results of ANOVA indicated that all the independent variables exhibited significant effect on the film properties. Chitosan concentration had a positive effect on CO2 permeability and negative effect on O2 while the glycerol concentration had a positive effect on permeability to both gases. Regarding water vapor permeability, the chitosan concentration had a negative effect, whereas the glycerol had no influence. Moreover, both chitosan and glycerol concentration influenced the elongation at break point (%A), and only glycerol concentration had a significant effect on tensile strength. Optimization by desirability approach was carried out on the independent variables to get the optimum levels within the experimental conditions. It was found that 1.5 % of chitosan and 25 % of glycerol (wt/wt of chitosan) retarded respiration and showed a strong permeability to water vapor. 相似文献
804.
Simulation of information propagation in real-life primate networks: longevity, fecundity, fidelity 总被引:1,自引:1,他引:0
In many vertebrate species, we find temporally stable traditions of socially learned behaviors. The social structure of animal
populations is highly diverse and it has been proposed that differences in the social organization influence the patterns
of information propagation. Here, we provide results of a simulation study of information propagation on real-life social
networks of 70 primate groups comprising 30 different species. We found that models that include the social structure of a
group differ significantly from those that assume random associations of individuals. Information spreads slower in the structured
groups than in the well-mixed groups. While we found only a minor effect on the path lengths of the transmission chains, robustness
against information extinction was strongly influenced by the group structure. Interestingly, robustness against information
loss was not correlated with propagation speed but could be predicted reasonably well by relative strength assortativity—a
structural network metric. In those groups where highly pro-social individuals preferentially interact with other pro-social
individuals, information was more likely to be lost. Our results show that incorporating group structure in any social propagation
model significantly alters predictions for spreading patterns, speed, and robustness of information. 相似文献
805.
Joël Meunier Luma Delaplace Michel Chapuisat 《Behavioral ecology and sociobiology》2010,64(10):1655-1663
The ability to discriminate against competitors shapes cooperation and conflicts in all forms of social life. In insect societies,
workers may detect and destroy eggs laid by other workers or by foreign queens, which can contribute to regulate reproductive
conflicts among workers and queens. Variation in colony kin structure affects the magnitude of these conflicts and the diversity
of cues used for discrimination, but the impact of the number of queens per colony on the ability of workers to discriminate
between eggs of diverse origin has so far not been investigated. Here, we examined whether workers from the socially polymorphic
ant Formica selysi distinguished eggs laid by nestmate workers from eggs laid by nestmate queens, as well as eggs laid by foreign queens from
eggs laid by nestmate queens. Workers from single- and multiple-queen colonies discriminated worker-laid from queen-laid eggs,
and eliminated the former. This suggests that workers collectively police each other in order to limit the colony-level costs
of worker reproduction and not because of relatedness differences towards queens’ and workers’ sons. Workers from single-queen
colonies discriminated eggs laid by foreign queens of the same social structure from eggs laid by nestmate queens. In contrast,
workers from multiple-queen colonies did not make this distinction, possibly because cues on workers or eggs are more diverse.
Overall, these data indicate that the ability of F. selysi workers to discriminate eggs is sufficient to restrain worker reproduction but does not permit discrimination between matrilines
in multiple-queen colonies. 相似文献
806.
Soil-to-root transfer and translocation of polycyclic aromatic hydrocarbons by vegetables grown on industrial contaminated soils 总被引:10,自引:0,他引:10
Fismes J Perrin-Ganier C Empereur-Bissonnet P Morel JL 《Journal of environmental quality》2002,31(5):1649-1656
Polycyclic aromatic hydrocarbons (PAHs) are possible contaminants in some former industrial sites, representing a potential risk to human health if these sites are converted to residential areas. This work was conducted to determine whether PAHs present in contaminated soils are transferred to edible parts of selected vegetables. Soils were sampled from a former gasworks and a private garden, exhibiting a range of PAH concentrations (4 to 53 to 172 to 1263 and 2526 mg PAHs kg-1 of dry soil), and pot experiments were conducted in a greenhouse with lettuce (Lactuca sativa L. var. Reine de Mai), potato (Solanum tuberosum L. var. Belle de Fontenay), and carrot (Daucus carota L. var. Nantaise). At harvest, above- and below ground biomass were determined and the PAH concentrations in soil were measured. In parallel, plates were placed in the greenhouse to estimate the average PAH-dust deposition. Results showed that the presence of PAHs in soils had no detrimental effect on plant growth. Polycyclic aromatic hydrocarbons were detected in all plants grown in contaminated soils. However, their concentration was low compared with the initial soil concentration, and the bioconcentration factors were low (i.e., ranging from 13.4 x 10(-4) in potato and carrot pulp to 2 x 10(-2) in potato and carrot leaves). Except in peeled potatoes, the PAH concentration in vegetables increased with the PAH concentration in soils. The PAH distribution profiles in plant tissues and in soils suggested that root uptake was the main pathway for high molecular weight PAHs. On the opposite, lower molecular weight PAHs were probably taken up from the atmosphere through the leaves as well as by roots. 相似文献
807.
808.
809.
Ozhan G Ozden S Alpertunga B 《Journal of environmental science and health. Part. B》2005,40(6):827-840
The present study describes the application of different solid-phase extraction techniques for the extraction, separation, and quantitative determination of 10 commonly used herbicides with different chemical structures (chlorsulfuron, diuron, bentazone, linuron, chlorpropham, fenoxoprop-ethyl, MCPA, diclofop-methyl, fluazifop-butyl, trifluraline) in water. Octadecyl (C(18)) Empore extraction disks, octadecyl (C(18)), and stryene divinylbenzene (SDB) Bond Elut Env cartridges were compared for solid-phase extraction efficiency. Herbicides were separated and quantified by reversed-phase high performance liquid chromatography with diode-array detection (HPLC-DAD) with simultaneous separation on two columns of differing polarity (C(18) and CN) to confirm identification. Analytical separation was performed simultaneously on C(18) and CN columns. Reanalysis of the sample extracts on a (cyano) CN column were used to confirm the identity of these compounds. Method optimization and validation parameters were presented in this work. Recoveries varied from 76.0% to 99.0% for C(18) disks, from 75.1% to 100.0% for C(18) cartridges, and from 54.0% to 98.0% for SDB cartridges over concentrations at 0.025--0.4 microg L(-1). The limits of detection were 0.012--0.035 microg L(-1). 相似文献
810.
S.?lópez-ridauraEmail author H.?Van.?Keulen M.?K.?van.?Ittersum P.?A.?Leffelaar 《Environment, Development and Sustainability》2005,7(1):51-69
Design and implementation of more sustainable natural resource management systems is the current objective of many research institutions, development agencies, NGOs and other stakeholders. But, how to assess whether a system is sustainable? How do we know whether the alternatives designed will increase the sustainability of the system? How to evaluate or assess the sustainability of natural resource management systems?In this paper we present a multiscale methodological framework for sustainability evaluation. The framework is based on a systems approach from which five general attributes of sustainable natural resource management systems are defined based on scale- and discipline-independent properties (productivity, stability, resilience, reliability and adaptability).A general operational strategy to derive ‘site-specific’ criteria and indicators for the attributes at different scales is also presented. This strategy is based on the definition of ‘impact scales’, at which the different stakeholders can or want to design alternatives, as well as the main stakeholders’ objectives and constraints. The application of the multiscale framework is illustrated with a case study in the Purhepecha Region of Michoacán, a peasant mountainous region in the west of Mexico. We used stakeholder consultation to identify the main objectives and constraints as well as to select criteria and indicators. The sets of criteria and indicators suggested for the different scales of analysis of the Purhepecha Region are comprehensive, yet not exhaustive, and represent the main issues related to natural resource management in the region. Further work will be directed towards the quantification of indicators at different scales and their relationships and trade-offs. 相似文献