The Sociable Lapwing(Vanellus gregarius) was recently categorized as Critically Endangered by the IUCN due to a strong decline and overall range contraction.Until now the only published Chinese record of the species w...The Sociable Lapwing(Vanellus gregarius) was recently categorized as Critically Endangered by the IUCN due to a strong decline and overall range contraction.Until now the only published Chinese record of the species was a vagrant sighting in 1998.We reviewed reports and historic literature from a German ornithological expedition in 1876,which reported the species to be a breeding bird in Xinjiang,western China in the second half of the 19th century.According to local expertise,the species seems since to have become extinct in Xinjiang,but surveys are suggested to clarify its current status.展开更多
The purpose of this paper is double： first to measure the natural radioactivity in any food by detecting the omnipresent radiation of ^40K, and then to use this date to obtain the concentration of the important miner...The purpose of this paper is double： first to measure the natural radioactivity in any food by detecting the omnipresent radiation of ^40K, and then to use this date to obtain the concentration of the important mineral nutrient K, by dividing the specific activity of the sample （Bq/g） by the specific activity of elementary K （31.19 Bq/g）. The method implies the γ rays detection emitted by natural ^40K-^40Ar present in foodstuff, by using a 3 × 3＂ low background NaI （TI） scintillation detector coupled to a PC charged with the Maestro Program. When this detection system is calibrated in order to determine its efficiency for 1461 KeV γrays emitted during ^40K-^40Ar decaying, it is possible to measure easily and with enough precision the specific activity due to natural ^40K present in any foodstuff. Once this figure is divided by the constant value of ^40K specific activity of elementary K, the concentration of this element in the foodstuff sample is established. This paper describes the procedure and shows the results obtained with four basic diet products： milk （powdered, light and cream）, eggs （yellow and white）, wheat （whole and refined flour） and corn （whole and cornstarch flour）. The possible application of this study seems to be to establish the necessary threshold to evaluate the importance of any possible radioactive contamination, as well as to measure the concentration of the mineral nutrient K in foodstuff, by means of an easy, practicable method. Also, it might be useful as an experiment for teaching purposes.展开更多
基金funded by the Darwin Initiative of the UK government and the Royal Society for the Protection of Birds (RSPB)support from Swarovski optics, The Rufford Foundation and Deutsche Ornithologen-Gesellschaft (DO-G)
文摘The Sociable Lapwing(Vanellus gregarius) was recently categorized as Critically Endangered by the IUCN due to a strong decline and overall range contraction.Until now the only published Chinese record of the species was a vagrant sighting in 1998.We reviewed reports and historic literature from a German ornithological expedition in 1876,which reported the species to be a breeding bird in Xinjiang,western China in the second half of the 19th century.According to local expertise,the species seems since to have become extinct in Xinjiang,but surveys are suggested to clarify its current status.
文摘The purpose of this paper is double： first to measure the natural radioactivity in any food by detecting the omnipresent radiation of ^40K, and then to use this date to obtain the concentration of the important mineral nutrient K, by dividing the specific activity of the sample （Bq/g） by the specific activity of elementary K （31.19 Bq/g）. The method implies the γ rays detection emitted by natural ^40K-^40Ar present in foodstuff, by using a 3 × 3＂ low background NaI （TI） scintillation detector coupled to a PC charged with the Maestro Program. When this detection system is calibrated in order to determine its efficiency for 1461 KeV γrays emitted during ^40K-^40Ar decaying, it is possible to measure easily and with enough precision the specific activity due to natural ^40K present in any foodstuff. Once this figure is divided by the constant value of ^40K specific activity of elementary K, the concentration of this element in the foodstuff sample is established. This paper describes the procedure and shows the results obtained with four basic diet products： milk （powdered, light and cream）, eggs （yellow and white）, wheat （whole and refined flour） and corn （whole and cornstarch flour）. The possible application of this study seems to be to establish the necessary threshold to evaluate the importance of any possible radioactive contamination, as well as to measure the concentration of the mineral nutrient K in foodstuff, by means of an easy, practicable method. Also, it might be useful as an experiment for teaching purposes.
