333 resultados para IUCN Red List
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
绿孔雀是国家I级重点保护鸟类. 在《Endangered Birds of the W orld-The ICBP Bird Red Data Book》(King, 1981)及《1990 IUCN Red List of Threatened Animals》中均将其列为易危种. 在CITES中被列入附录2. 据文献记载:绿孔雀在中国分布于云南(郑作新, 1987)和西藏东南部(尹秉高等, 1993). 历史上云南东南部的开远、建水和文山县曾记载有绿孔雀分布(《云南通志》, 明隆庆六年, 1572). 现代著作中(彭燕章等, 1987; 郑宝责等, 1987; 张帆等, 1987; 杨岚, 1989, 1991; 文贤继等, 1995; 杨晓君, 1995)记录云南省东南部的蒙自、金平、绿春、河口、弥勒、建水、石屏等7个县有绿孔雀分布. 另据当地群众反映在滇西北迪庆州发现有绿孔雀. 作者于1995年4-6月、11-12月和1996年4-6月在以往对绿孔雀分布现状调查(文贤继等, 1995)的基础上, 对云南东南部和西北部绿孔雀的分布现状及保护情况又进行了调查, 本次调查对绿孔雀在上述地区的分布状况进行了核实, 为今后的生态生物学研究和保护工作提供了有关资料。
Resumo:
依据线粒体上ND2和CO1两个变异较大的基因序列分析了香港地区香港湍蛙7种群、华南湍蛙1种群,以及大陆其他地区华南湍蛙7种群,戴云湍蛙1种群,武夷湍蛙1种群的系统发育关系,进而探讨香港湍蛙的遗传多样性、香港湍蛙特有性、如何确定香港湍蛙最佳保护单元以及这四种湍蛙的物种分类地位。
1. 香港湍蛙保护遗传学研究
香港湍蛙核苷酸传多样性较低,从其遗传多样性信息、单倍型网络分析、中性检验值以及岐点分布结果一致显示香港湍蛙很可能经历了瓶颈后的扩张,种群正在由一个较小的有效种群大小迅速增长, 有足够的时间通过变异用于积累单倍型的多态性, 而对于提高核苷酸多样化而言, 时间尚短(Nei M et al,1975,Avise J C,2000;李明等,2003)。
分子变异分析结果显示香港湍蛙种群间存在较多的基因交流,且系统发育树上各种群间交叉在一起,没有形成与地理单元相关的分支,而从其单倍型网络看,他们源于共同的祖先,是一个单系群,与地理单元间没有形成显著的遗传分化。因此应作为一个进化显著单元(ESU)。结合其与其他湍蛙发育关系及遗传距离以及野外采集信息认为香港湍蛙只在香港地区有分布,属于香港特有种。该物种内遗传多样性较低,又属于世界自然保护联盟红皮书中的近危种,同时也是《野生动物保护条例》中的受保护野生动物,且由于香港城市建设等使得其栖息环境受到威胁,因此在香港特别行政区应该受到重点保护。
从单倍型分布和核苷酸多样性可以看出大榄涌种群和城门种群具有较高的单倍型多样性和核苷酸多样性,应该作为保护的重点区域。
2. 华南湍蛙东、南沿海种群间系统关系
华南湍蛙分布广,各种群存在着丰富的遗传多样性信息且中部种群广西龙胜和湖南张家界种群核苷酸多样性明显高于其他边缘种群华南湍蛙。种群间几乎没有基因交流,且各种群间无共享单倍型,可见已形成了显著的遗传分化。各种群间遗传距离都较远,其中广东南昆山种群以及福建三港种群与其他种群距离最远,因此可以推测其他种群(广东深圳、香港大屿山、广西龙胜和防城以及湖南张家界种群)可能为独立进化的种群。但是否是一新种或一隐存种,还需要结合形态学进行更深入的研究。
本研究中无论从系统关系看还是从遗传距离看,大屿山种群与深圳种群最近,支持陈坚峰等将其定为华南湍蛙,即华南湍蛙新增一个分布点:香港大屿山。
系统树上广西防城种群(支B)与龙胜和湖南种群(支A)形成姐妹群。香港大屿山种群与深圳种群先形成姐妹群(支C),但却没有与其距离很近的广东南岭及南昆山种群(支D)形成姐妹群,可能粤北和粤中的环境及气候较复杂因此与粤南其他种群形成了明显的隔离。同时可以看出华南湍蛙种群遗传分化与地理距离没有显著的相关性。
3. 四种湍蛙间的系统关系
根据线粒体CO1基因建立四种湍蛙间的系统关系及其遗传距离,很清楚地看到,香港湍蛙与戴云湍蛙关系很近,而华南湍蛙则与武夷湍蛙较近。然而,戴云湍蛙同一个种群内部共有两个单倍型DY1和DY2,且两个单倍型间遗传距离大于DY1与香港湍蛙间遗传距离,更远远大于香港湍蛙种群内部的距离,即戴云湍蛙内部两个单倍型间遗传距离达到了种级水平,同样在系统发育树上这两个单倍型与香港湍蛙形成并系。但是,戴云湍蛙种内在形态上差异不显著。因此,其是否属于萌芽物种分化形成(budding speciation)或已经完全分化为两个不同的种值得进一步研究?
与戴云湍蛙香港湍蛙关系类似,从系统树上看华南湍蛙不形成单系,而是分成两个大支,与武夷湍蛙形成并系,且福建和南昆山的华南湍蛙与武夷湍蛙遗传距离远大于武夷湍蛙种内福建种群与浙江种群的遗传距离,达到了种级分化水平。由此,可以推断武夷湍蛙是有效种。系统树上广东深圳、香港大屿山、广西防城和龙胜以及湖南张家界种群与华南湍蛙福建及南昆山各种群间遗传距离已超出了种内各种群间的遗传距离,但是至于这一支是否应为另外一个种,有必要扩大采样,并结合核基因及形态信息进行进一步研究。
MtDNA of ND2 and CO1 gene were used to investigate genetic diversity of Amolops in Hongkong .We collected seven populations of A. hongkongensis,,one population of A.ricketti from Hong Kong and other seven populations of A.ricketti from East and South of Chinese mainland. As well as one population of A. daiyunensis and one population of A.wuyiensis Phylogenetic relationship were analyzed of four species. Discussed whether A.hongkongensis is an endemic species and how can we make the conservation and management decisions.
1. Conservation Genetics of A. hongkongensis
A. hongkongensis has a low nucleotide diversity, the results of genetic diversity, haplotype network, neutrality test and the mismatch distributions indicate that A. hongkongensis experienced a recent expansion after a bottle neck. They had enough time to accumulated haplotype diversity, but it’s too short to have a high nucleotide diversity(Nei M et al,1975,Avise J C,2000;Li et al,2003).
The result of AMOVA reveals that it has much gene exchange among the populations of A. hongkongensis. The clades of the phylogenetic tree were mixed together, no significant genetic differentiation among 8 populations and they share the same ancestor from the network analysis, these indicate that they are monophyly and should be protected as one ESU. Combined with the information of relationships of interspecies, genetic distance and distribution investigate, We conclude that A. hongkongensis is an endemic species of Hong Kong. Considering on the status of low genetic diversity in A.hongkongensis, and this species was listed in the IUCN red list as near threatened, as well as listed in the
Resumo:
A new species of Orinus Hitchcock, O. alticulmus L. B. Cai & Tong Lin Zhang, is described and illustrated. This species is endemic to Qinghai province, China, occurring at altitudes of 2450-2600 m on sandy soils. It resembles O. kokonorica (K. S. Hao) Tzvelev, but differs from that species by its slightly effuse panicles, longer spikelets usually with five or six florets, purple-yellow anthers, shorter caryopses, and the paleas usually longer than the lemmas. A key to the five species of the genus is provided.
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Red-shift conical emission (CE) is observed by femtosecond laser pulse propagating in BK7 at a low input power (compared to those input powers for generation of blue-shift CE). With the increasing input power the blue-shift CE begins to appear whereas the red-shift CE ring (902 nm in our experiment) disappears accompanied by the augment of the central white spot size synchronously. The disappearing of red-shift CE in our experiment is explained such that the increase of axial intensity is much higher than that of ring emission and the augment of the central white spot size with the increasing input laser power.
Resumo:
The characteristics of backward harmonic radiation due to electron oscillations driven by a linearly polarized fs laser pulse are analysed considering a single electron model. The spectral distributions of the electron's backward harmonic radiation are investigated in detail for different parameters of the driver laser pulse. Higher order harmonic radiations are possible for a sufficiently intense driving laser pulse. We have shown that for a realistic pulsed photon beam, the spectrum of the radiation is red shifted as well as broadened because of changes in the longitudinal velocity of the electrons during the laser pulse. These effects are more pronounced at higher laser intensities giving rise to higher order harmonics that eventually leads to a continuous spectrum. Numerical simulations have further shown that by increasing the laser pulse width the broadening of the high harmonic radiations can be controlled.
Resumo:
The effect of alcohol solution on single human red blood Cells (RBCs) was investigated using near-infrared laser tweezers Raman spectroscopy (LTRS). In our system, a low-power diode laser at 785 nm was applied for the trapping of a living cell and the excitation of its Raman spectrum. Such a design could simultaneously reduce the photo-damage to the cell and suppress the interference from the fluorescence on the Raman signal. The denaturation process of single RBCs in 20% alcohol solution was investigated by detecting the time evolution of the Raman spectra at the single-cell level. The vitality of RBCs was characterized by the Raman band at 752 cm(-1), which corresponds to the porphyrin breathing mode. We found that the intensity of this band decreased by 34.1% over a period of 25 min after the administration of alcohol. In a further study of the dependence of denaturation on alcohol concentration, we discovered that the decrease in the intensity of the 752 cm(-1) band became more rapid and more prominent as the alcohol concentration increased. The present LTRS technique may have several potential applications in cell biology and medicine, including probing dynamic cellular processes at the single cell level and diagnosing cell disorders in real time. Copyright (c) 2005 John Wiley T Sons, Ltd.
Resumo:
A laser beam at wavelength 647 nm is focused on a sample of 5 mol% MgO-doped lithium niobate crystal for domain inversion by a conventional external electric field. In this case, a reduction of 36% in the electric field required for domain nucleation (nucleation field) is observed. To the best of our knowledge, it is the longest wavelength reported for laser-induced domain inversion. This extends the spectrum of laser inducing, and the experimental results are helpful to understand the nucleation dynamics under laser illumination. The dependence of nucleation fields on intensities of laser beams is analysed in experiments.
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An interesting fluorescence intensity reverse photonic phenomenon between red and green fluorescence is investigated. The dynamic range. of intensity reverse between red and green fluorescence of Er( 0.5) Yb( 3): FOV oxyfluoride nanophase vitroceramics, when excited by 378.5nm and 522.5nm light respectively, is about 4.32 x 10(2). It is calculated that the phonon- assistant energy transfer rate of the electric multi- dipole interaction of {(4)G(11/2)( Er3+) -> F-4(9/2)( Er3+), F-2(7/2)( Yb3+). F-2(5/2)( Yb3+)} energy transfer of Er( 0.5) Yb( 3): FOV is around 1.380 x 10(8) s(-1), which is much larger than the relative multiphonon nonradiative relaxation rates 3.20 x 10(5) s(-1). That energy transfer rate for general material with same rare earth ion's concentration is about 1.194 x 10(5) s(-1). These are the reason to emerge the unusual intensity reverse phenomenon in Er( 0.5) Yb( 3): FOV. (C) 2007 Optical Society of America.
Resumo:
Structural and infrared-to-visible upconversion fluorescence properties in ytterbium-sensitized erbrium-doped novel lead-free germanium bismuth-lanthanum glass have been studied. The structure of lead-free germanium-bismuth-lanthanum glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wavenumbers. Intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions 2H(11/2) -> I-4(15/2), S-4(3/2) -> I-4(15/2), and F-4(9/2) -> I-4(15/2), respectively, were observed at room temperature. The quadratic dependence of the 525, 546, and 657 nm emissions on excitation power indicates that a two-photon absorption process occurs under 975 nm excitation. This novel lead-free germanium-bismuth-lanthanum glass with low maximum phonon energy (similar to 751 cm(-1)) can be used as potential host material for upconversion lasers. (c) 2005 Published by Elsevier B.V.
Resumo:
We report a novel phenomenon in GeS2-In2S3-CsI chalcohalide glass doped with Tm3+ ions. Under irradiation with an 808 nm laser diode, a bright red emission centered at 700 nm is observed for the first time in this glass. The log-log correlation between integrated emission intensity and pump power reveals that a two-photon absorption process is involved in the phenomenon, suggesting that the F-3(3,2) -> H-3(6) transition of Tm3+ ions is responsible for the appearance of the red emission. The results indicate that the indium (In) based chalcohalide glass containing Tm3+ ions is expected to find applications in visible lasers, high density optical storage and three-dimensional color displays. (C) 2009 Elsevier B.V. All rights reserved.