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Rock ptarmigan (Lagopus muta) and willow ptarmigan (L. lagopus) are Arctic birds with a circumpolar distribution but there is limited knowledge about their status and trends across their circumpolar distribution. Here, we compiled information from 90 ptarmigan study sites from 7 Arctic countries, where almost half of the sites are still monitored. Rock ptarmigan showed an overall negative trend on Iceland and Greenland, while Svalbard and Newfoundland had positive trends, and no significant trends in Alaska. For willow ptarmigan, there was a negative trend in mid-Sweden and eastern Russia, while northern Fennoscandia, North America and Newfoundland had no significant trends. Both species displayed some periods with population cycles (short 3–6 years and long 9–12 years), but cyclicity changed through time for both species. We propose that simple, cost-efficient systematic surveys that capture the main feature of ptarmigan population dynamics can form the basis for citizen science efforts in order to fill knowledge gaps for the many regions that lack systematic ptarmigan monitoring programs.

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Despite low levels of organochlorine contaminants (OCs) in Antarctic biota, some compounds may exceed the levels in equivalent Arctic species, and previous studies have found biochemical evidence of pollutant exposure in south polar skuas (Catharacta maccormicki), a common marine top predator in the region. In this study we examined relationships between fitness components (fecundity and adult return rate between breeding seasons) and concentrations of OCs in this species. In 65 nests, both males and females were caught, and using principal component analyses (PCA) we produced composite measurements (PC1 and PC2) of six highly correlated OCs measured in blood samples. Although the concentrations of OC were below those documented to have reproductive effects in other aquatic birds, we found that the eggs of females with high levels of OCs in the blood hatched later, and their chicks were in poorer condition at hatching, than females with low OC levels. Thus OCs may delay reproduction and reduce foetal growth in the skuas. However, there was no relationship between the parents' OC residues and the occurrence of non-viable eggs, although the proportion of nests containing non-viable eggs was high (47%). Moreover, there were no significant relationships between OCs and reproductive variables in males, even if males had higher OC levels than females, and no associations between OCs and adult return rate between breeding seasons.  相似文献   
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A procedure for the determination of cadmium, copper, manganese, and zinc in Turkish tobaccos, which were of different origins, years, and grades, and in the butt, ash, and smoke, which were obtained by smoking the cigarettes that were prepared manually from the said tobaccos in a smoking apparatus, was devised as proposed. The collected samples were digested by wet ashing technique by using HNO3-HClO4 and were analyzed by flame atomic absorption spectrometry with satisfactory recoveries (94 % to 98 %). The regression coefficients were above 0.99, and the detection limits were in the range of 0.03–0.12 mg/L?1. The performance and accuracy of the method was tested by analyzing “Certified Reference Material GBW 08501-Peach Leaves.” The determined values were in agreement with the standard values for the heavy metals analyzed. Thus, it was concluded that the developed method could offer a wide range of application for establishing a relationship between the makeup and composition of tobacco plant, products, ash, smoke, and smoking.  相似文献   
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