摘要 :
Carotenoids are synthesized by plants, therefore insects and birds must obtain them from their diet. They function in pigmentation and as antioxidants. We studied the carotenoid profiles in a model food chain (plant-insect-bird) i...
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Carotenoids are synthesized by plants, therefore insects and birds must obtain them from their diet. They function in pigmentation and as antioxidants. We studied the carotenoid profiles in a model food chain (plant-insect-bird) in an air pollution gradient to find out whether heavy metal pollution affects the transfer of carotenoids across the trophic levels. Birch leaves showed higher β-carotene and, one of the birch species (Betula pendula), higher total carotenoids levels in the polluted area. There was no difference in the lutein concentration of caterpillars' food source, birch leaves, between the study areas. Autumnal moth larvae accumulated lutein more efficiently than β-carotene while sawfly larvae accumulated β -carotene over lutein. Because of different antioxidant profiles in different leaf chewing insects their sensitivity to pollution stress may differ. The lutein concentration of plasma and feathers of Great tit nestlings did not differ along the pollution gradient. The lack of difference in lutein concentration of autumnal moth larvae along pollution gradient may partly explain the lutein concentrations of Great tit nestlings, since the abundance of autumnal moth larvae peak during the nestling phase of Great tit. The lutein concentration of autumnal moth larvae was positively associated to circulating plasma lutein level of Great tit indicating the importance of carotenoid rich diet during the nestling phase. In addition, the higher the plasma lutein concentration the more lutein was deposited to feathers, irrespective of the other possible functions of lutein in nestlings. We found that carotenoid levels differed between the polluted and the unpolluted area especially at lower levels of food chain: in birches and in caterpillars.
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摘要 :
The radio spectrum at MRO suffers from local electronics, broadband television, DBV-T, FM-radio, and some local data-links of nearby Schengen police communication and hence Metsähovi in the present situation is not ideal as a hos...
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The radio spectrum at MRO suffers from local electronics, broadband television, DBV-T, FM-radio, and some local data-links of nearby Schengen police communication and hence Metsähovi in the present situation is not ideal as a host site for a solar frequency agile or even to have an FFT spectrometer used at low frequencies. The general situation will be notably improved by installing the whole system at a more remote location or by improving the shielding of nearby electronic equipment. Also during the weekends, RFI-levels seem to be notably lower than during the office hours. Nevertheless it will be possible to detect strong flares with more than 50 sfu. A larger antenna with more gain would improve the situation drastically due to the fact that the signal-to-noise ratio of the solar flares would improve. Also a pre-amplifier with better noise figure and larger gain could improve the whole system's noise temperature. The most harmful interference frequencies are generated by the local electronics. However, during the observations the antenna is pointed away from the laboratory buildings. Thus the spectra is reasonable during observations, especially at higher frequencies (>300 MHz). The first results have shown that the measurement system is operating reliably and it can detect some weak solar radio bursts.
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