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Clotilde Biard Nicolas Saulnier Maria Gaillard Jérôme Moreau 《Die Naturwissenschaften》2010,97(11):987-995
In the study of parasite-mediated sexual selection, there has been controversial evidence for the prediction that brighter
males should have fewer parasites. Most of these studies have focused on one parasite species. Our aim was to investigate
the expression of carotenoid-based coloured signals in relation to patterns of multiple parasite infections, to determine
whether colour reflects parasite load of all parasite species, or whether different relationships might be found when looking
at each parasite species independently. We investigated the relationship between bill colour, body mass and plasma carotenoids
and parasite load (feather chewing lice, blood parasite Plasmodium sp., intestinal parasites cestodes and coccidia) in the blackbird (Turdus merula). Bill colour on its own appeared to be a poor predictor of parasite load when investigating its relationships with individual
parasite species. Variation in parasite intensities at the community level was summarised using principal component analysis
to derive synthetic indexes of relative parasite species abundance and absolute parasite load. The relative abundance of parasite
species was strongly related to bill colour, plasma carotenoid levels and body mass: birds with relatively more cestodes and
chewing lice and relatively less Plasmodium and coccidia had a more colourful bill, circulated more carotenoids and were heavier. These results suggest that bill colour
more accurately reflects the relative intensities of parasite infection, rather than one-by-one relationships with parasites
or absolute parasite burden. Investigating patterns of multiple parasite infection would thus improve our understanding of
the information conveyed by coloured signals on parasite load. 相似文献
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Pierre-Franois Biard Annabelle Couvert Christophe Renner Jean-Pierre Levasseur 《Chemosphere》2009,77(2):182-187
Dimethyl disulphide (DMDS) removal was investigated in a compact scrubber (hydraulic residence time ≈20 ms), composed of a wire mesh packing structure where liquid and gas flow at co-current and high gas superficial velocity (>12 m s−1). In order to regenerate the scrubbing liquid and to maintain a driving force in the scrubber, ozone and hydrogen peroxide were added to water since they allow the generation of nonselective and highly reactive species, hydroxyl radicals HO. Three ways of reagent distribution were tested. The influence of several parameters (liquid flow rate(s), ozone flow rate, pH and reagent concentrations) was investigated. The best configuration was obtained when ozone is transferred in the scrubbing liquid before introduction at the top of the scrubber simultaneously with the hydrogen peroxide solution, allowing to generate hydroxyl radical in the scrubber. With this configuration, DMDS removal could be increased from 16% with water to 34% at the same gas and liquid flow rates in the scrubber showing the potentiality of advanced oxidation process. 相似文献
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