The Purple Swamphen(Porphyrio porphyrio)is a rare species with an extremely small range in China.From March to June in 2005 and 2006,we investigated the nest-site selection of the Purple Swamphen in the Guangdong Haif...The Purple Swamphen(Porphyrio porphyrio)is a rare species with an extremely small range in China.From March to June in 2005 and 2006,we investigated the nest-site selection of the Purple Swamphen in the Guangdong Haifeng Avian Natural Reserve,China.Nests were bowlshaped or shallow cups with most of them constructed in hydrophyte clusters of Scirpus tabernaemontani.Distance to road and distance to water edge were significantly different between nest sites and non-nest sites and were important for determining nesting sites based on stepwise discriminant analysis.Our results suggest restoring and protecting the extant nesting areas is essential for effective conservation of the Purple Swamphen in China.展开更多
We report the discovery of Balmer broad absorption lines （BALs） in the quasar LBQS 1206＋1052 and present a detailed analysis of the peculiar absorption line spectrum. Besides the Mg II λλ2796, 2803 doublet, BALs ...We report the discovery of Balmer broad absorption lines （BALs） in the quasar LBQS 1206＋1052 and present a detailed analysis of the peculiar absorption line spectrum. Besides the Mg II λλ2796, 2803 doublet, BALs are also detected in the He I＊ multiplet at λλ2946, 3189, 3889 A arising from the metastable helium 2 3 S level, and in Hα and Hβ from the excited hydrogen H I＊ n = 2 level, which are rarely seen in quasar spectra. We identify two components in the BAL troughs of v ～ 2000 km s 1 width： One component shows an identical profile in H I＊, He I＊ and Mg II with its centroid blueshifted by v c ≈ 726 km s-1 . The other component is detected in He I＊ and Mg II with v c ≈ 1412 km s-1 . We estimate the column densities of H I＊, He I＊, and Mg II, and compare them with possible level population mechanisms. Our results favor the scenario that the Balmer BALs originate in a partially ionized region with a column density of N H ～ 10 21 10 22 cm-2 for an electron density of n e ～ 10 6 10 8 cm-3 via Lyα resonant scattering pumping. The harsh conditions needed may help to explain the rarity of Balmer absorption line systems in quasar spectra. With an i-band PSF magnitude of 16.50, LBQS 1206＋1052 is the brightest Balmer-BAL quasar ever reported. Its high brightness and unique spectral properties make LBQS 1206＋1052 a promising candidate for followup high-resolution spectroscopy, multi-band observations, and long-term monitoring.展开更多
基金supported by the National Natural Science Foundation of China(30770311)the Field Front Project of the Knowledge Innovation Program of the Chinese Academy of Sciences(2010)the Field Station Foundation of the Guangdong Academy of Sciences(2005,2006,2008,2009)
文摘The Purple Swamphen(Porphyrio porphyrio)is a rare species with an extremely small range in China.From March to June in 2005 and 2006,we investigated the nest-site selection of the Purple Swamphen in the Guangdong Haifeng Avian Natural Reserve,China.Nests were bowlshaped or shallow cups with most of them constructed in hydrophyte clusters of Scirpus tabernaemontani.Distance to road and distance to water edge were significantly different between nest sites and non-nest sites and were important for determining nesting sites based on stepwise discriminant analysis.Our results suggest restoring and protecting the extant nesting areas is essential for effective conservation of the Purple Swamphen in China.
基金supported by the National Natural Science Foundation of China(Grants Nos.10973013 and 11033007)the Fundamental Research Funds for the Central Universities through grant WK 2030220006+8 种基金the SOA project CHINARE2012-02-03Funding for the SDSS and SDSS-Ⅱ has been provided by the Alfred P.Sloan Foundationthe Participating Institutionsthe National Science Foundationthe U.S. Department of Energythe National Aeronautics and Space Administrationthe Japanese Monbukagakushothe Max Planck Societythe Higher Education Funding Council for England
文摘We report the discovery of Balmer broad absorption lines （BALs） in the quasar LBQS 1206＋1052 and present a detailed analysis of the peculiar absorption line spectrum. Besides the Mg II λλ2796, 2803 doublet, BALs are also detected in the He I＊ multiplet at λλ2946, 3189, 3889 A arising from the metastable helium 2 3 S level, and in Hα and Hβ from the excited hydrogen H I＊ n = 2 level, which are rarely seen in quasar spectra. We identify two components in the BAL troughs of v ～ 2000 km s 1 width： One component shows an identical profile in H I＊, He I＊ and Mg II with its centroid blueshifted by v c ≈ 726 km s-1 . The other component is detected in He I＊ and Mg II with v c ≈ 1412 km s-1 . We estimate the column densities of H I＊, He I＊, and Mg II, and compare them with possible level population mechanisms. Our results favor the scenario that the Balmer BALs originate in a partially ionized region with a column density of N H ～ 10 21 10 22 cm-2 for an electron density of n e ～ 10 6 10 8 cm-3 via Lyα resonant scattering pumping. The harsh conditions needed may help to explain the rarity of Balmer absorption line systems in quasar spectra. With an i-band PSF magnitude of 16.50, LBQS 1206＋1052 is the brightest Balmer-BAL quasar ever reported. Its high brightness and unique spectral properties make LBQS 1206＋1052 a promising candidate for followup high-resolution spectroscopy, multi-band observations, and long-term monitoring.
