905 resultados para Bird, Lester


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2007年5月,在云南南部思茅地区(今普洱市)江城县西南部的整董镇附近发现棕臀噪鹛(Garrulax gularis),调查表明该种在江城南部沿中国-老挝边界一带分布;此发现为该种在中国的首次正式纪录,期待今后在西藏东南部地区对该种有新的发现.

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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。

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Although Southeast Asia is a global biodiversity hotspot, the tempo and mode of avian diversification there has not been well studied. We investigated the history of the diversification of an endemic Asian tropical bird, the Black-browed Barbet Megalaima

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:自20世纪80年代末期应用基于Argos系统的卫星跟踪技术开展候鸟迁徙研究以来,鸟类学家取得了 许多利用传统鸟类迁徙研究方法所无法取得的成果。但在中国,卫星跟踪技术在鸟类迁徙中的应用尚属空白。作 者利用参与中国首次应用卫星跟踪技术跟踪候鸟迁徙研究之机,对该技术用于候鸟迁徙研究的技术平台、主要内 容和未来研究进行了综述和展望。利用卫星跟踪技术开展的主要研究内容有:揭示迁徙路线和重要停歇地点;寻 找新繁殖地和越冬地;利用卫星数据对栖息地及其利用进行评价;探讨鸟类的迁徙策略。期望该技术能够成为中 国濒危鸟类保护的有效方法,并尽快得到应用。

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2006年10月28日凌晨3点,笔者在位于云南省新平县哀牢山的金山丫口鸟类环志站进行夜间鸟类环志工作时,用灯光诱捕到一只鹭科鸟类,经鉴定为海南(Gorsachius magnificus),为云南省鸟类物种新记录。形态特征:头和颊部黑褐色;枕部具黑褐色的延长羽冠;有明显的白色眼后条纹,颊纹白色;眼球外凸,黄绿色的眼睑向外伸出;眼先裸露皮肤呈黄绿色;喉白,中央有褐色条纹;颈侧棕色,前端有黑色条纹,前颈具褐白斑驳的条纹,后颈黑褐色;背部、翅和尾羽褐色;第一枚初级飞羽外栗红色;胸、腹部、尾下覆羽及翅下覆羽白色,杂有褐色斑纹;上嘴黑色,下嘴嘴基黄色,嘴端黑色;虹膜褐色(中国鸟类野外手册上记载的虹膜为黄色,MacKinnon et al,2000);跗黄绿色。雌性标本量度(g,mm)如下:体重563,全长565,嘴峰72,翅长305,尾长111,跗76。海南是中国的特有种鸟类,属国家Ⅱ级重点保护鸟类。分布于中国南方的少数地区,国外仅在越南东京有过一次记录(MacKinnon et al,2000),种群数量稀少,过去曾记录于安徽、浙江、福建(Cheng,1987)、海南、广西及广东(Gao et al,200...

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Lake Chilwa and its environs present a unique challenge to science for two reasons: 1. The welfare of its people and the fish and crops on which they depend on incomes as well as subsistence are dominated by the vagaries of the periodic rise and fall of the lake. Inyears of high level the lake provides a relatively good living for the people of the plain and the fish is a major source of dietary protein for the densely populated Shire Highlands. Fish catches and fish consumption decline in years of low lake level. Could knowledge of the biology of the lake and the hydrology of the lake basin assist in stabilizing the fishing industry? 2. The area is underdeveloped, with the traditional matrilineal way of life, but it has considerable potential for a fishing industry, for agriculture, for livestock, for bird preservation and tourism and possibly, at some future date, for minerals. How can these interests be reconciled and in what order should developments take place?

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著名鸟类学家N.J.Collar在英国东方鸟类学会(The Oriental Bird Club)最新一期的Forktail上发表文章,对亚洲鹛类(文中用的是Timaliidae———画眉科)中一些种类的分类地位做了厘正,涉及多个在中国有分布的种类,其中包括将黄喉噪鹛东南亚种Garrulax galbanus courtoisi重新升格为独立种G.courtoisi[1]。1923年,法国鸟类学会会长M.A.Ménégaux依据1919年采自江西婺源(当时属安徽省)的两号标本发表了新种Garrulas courtoisi[2]。J.Berlioz随之将其归为黄喉噪鹛G.galbanus下的一亚种[3]。1958年,郑作新将1956年3月在云南思茅石头山采到的3只标本定名为G.g.courtoisi[4];1982年,郑作新、唐瑞昌又依据这3号标本发表了思茅亚种G.g.simaoensis[5]。1994年,Long等人即已指出应将黄喉噪鹛G.galbanus视为单型种,而将courtoisi和simaoensis分立之[6]。Inskipp等人也指出courtoisi(包括simaoensis)与galban

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Bioaccumulation of PCDD/F in the foodweb was investigated in the Ya-Er Lake area, which was heavily polluted by PCDD/F. The high concentrations of PCDD/F in sediment can be transferred and bioaccumulated by aquatic organisms and humans through various pathways. Benthonic invertebrate animals and aquatic plants with a lot of fibers in the root can accumulate PCDD/F from sediment and water. Snail (Bellamya aeruginosa), shrimp (Macrobranchium sp.) and freshwater mussel (Acuticosta chinensis (Lea)) took up PCDD/F from the water and maintained the emission patterns, whereas fish tended to selectively accumulate 2,3,7,8-substituted isomers. The tissues of fish-eating bird and duck (Anas platyrhynchos) were very highly contaminated by PCDD/F due to ingestion of fish and other aquatic organisms from sediment. The residual concentration in breast milk depended on the original concentration of PCDD/F in the food. A resident in Ya-Er Lake area showed a daily intake of PCDD/ F of about 9.14 pg TEQ/kg body weight/day. This is higher than the tolerable daily intake (TDI) for PCDD/F (1 pg TEQ/kg body weight/day), which was recommended by the World Health Organization (WHO). (C) 2001 Elsevier Science Ltd. All rights reserved.

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We analyse the operation of a semiconductor nanowire-based memory cell. Large changes in the nanowire conductance result when the magnetization of a periodic array of nanoscale magnetic gates, which comprise the other key component of the memory cell, is switched between distinct configurations by an external magnetic field. The resulting conductance change provides the basis for a robust memory effect, which can be implemented in a semiconductor structure compatible with conventional semiconductor integrated circuits.

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为提高喷灌水量分布均匀性评价的准确性,当雨量筒径向布置时,为考虑所有测点数据对插值点降水深的影响,采用径向和周向两次的三次样条插值计算出未知点的降水深,从而计算喷灌均匀系数。以美国雨鸟30PSH型喷头雨量筒间隔为1m和2m的喷洒试验数据,计算网格点取1m和0.25m,分别采用三次样条两次插值法和邻近四点距离线性插值法计算了克里斯琴森均匀系数。结果表明,均匀系数由高至低的顺序依次为采样间隔为2m的线性插值、采样间隔为2m的三次样条两次插值、采样间隔为1m的线性插值和采样间隔为1m的三次样条两次插值。采样间隔2m比1m计算出的均匀系数总体高3~4个百分点,三次样条两次插值法比邻近点距离线性插值法略低1个百分点,2种计算网格点间距下的均匀系数差值小于1个百分点。结果证明,采样间距、插值方法、计算网格间距对均匀系数的影响依次降低,三次样条两次插值法可以用来评价喷灌组合均匀系数。

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现代多脉冲及2D NMR技术是过去十年中发展起来的崭新的NMR实验方法。计算机模拟做为NMR实验的强有力分析手段已日益受到重视。国内这方面工作开展得尚很少;国外发表的工作主要采用的是数字模拟,存在分析结果不够直观、物理意义不够清晰等缺陷。本论文工作采用乘积算符方法研制出对分析多脉冲及2D NMR实验普适的模拟程序PROPER;在乘积算符基础上,针对磁等性自旋体系,提出了实用的对称化乘积算符及多量子积算符方法。一、多脉冲及2D NMR实验的计算机模拟 1. 采用乘积算符方法在本所PDP-11/23微机上研制了多脉冲及2D NMR实验的模拟程序PROPER。该程序对不超过4核(I = 1/2)的同核及异核弱耦合自旋体系非选择性脉冲序列的分析是普遍适用的。受计算机内存的限制,PROPER程序所能处理的脉冲序列脉冲间隔数目一般不超过10。2. 应用PROPER模拟程序对INEP和DEPT脉冲序列进行了分析比较;特别对BIRD脉冲序列的各种相位变型进行了模拟分析,给出了分析结果,分析过程中考虑了影响BIRD作用效果的同核耦合因素。应用结果表明,PROPER程序计算正确、迅速、给出的模拟结果较通常的数字模拟方法简单、直观、物理意义清楚,便于分析。由于采用算符模拟,结果的输出打印比较费时。目前,PROPER程序正在改进和完善之中。二、多脉冲及2D NMR实验的密度算符描述 1. 针对磁等性自旋(I = 1/2)体系,首次提出了对称化乘积算符描述方法。在通常的乘积算符基础上,引入了对称化乘积算符,并对其数理基础进行了详细论证。推导了算符循环对易关系决定的Liourill-Von Neumann方程的解,给出了算符间普遍存在的循环对易关系及其相应的演化公式。据此,以InS(I = 1/2, S = 1/2; n = 2,3)自旋体系为例,对DEPT脉冲序列进行了分析;结果表明,该方法较通常的乘积算符方法对磁等性自旋体系的分析要简单、实用,且物理意义更加明确。由于该方法涉及较多的算符对易关系,因此不易计算机编程。2. 在对称化乘积算符基础上引入了多量子积算符的概念。以In(I = 1/2; n = 2,3)体系为例,给出了两者的互换关系。推导出了具有标量耦合作用的两组合粒子体系普适的多量子积算符环对易关系及相应的演化解析式。多量子积算符方法可望将1/2-自旋磁等性组合粒子表象与自旋大于1/2的单粒子表象统一起来,并为计算机模拟提供新的数学方法。该方法尚有待于进一步研究。