Potential refugium on the Qinghai-Tibet Plateau revealed by the chloroplast DNA phylogeography of the alpine species Metagentiana striata (Gentianaceae)

Metagentiana striata is an alpine annual herbaceous plant endemic to the east of the Qinghai-Tibet (Q-T) Plateau and adjacent areas. The phylogeography of M. striata was studied by sequencing the chloroplast DNA (cpDNA) trnS-trnG intergenic spacer. Ten haplotypes were identified from an investigation of 232 individuals of M. striata from 14 populations covering the entire geographical range of this species. The level of differentiation amongst populations was very high (G(ST) = 0.746; N-ST = 0.774) and a significant phylogeographical structure was observed (P < 0.05). An analysis of molecular variance found a high variation amongst populations (76%), with F-ST = 0.762 (highly significant, P < 0.001), indicating that little gene flow occurred amongst the different regions; this was explained by the isolation of populations by high mountains along the Q-T Plateau and adjacent areas (N-m = 0.156). Only one ancestral haplotype (A) was common and widespread throughout the distributional range of M. striata. The populations of the Hengduan Mountains region of the south-eastern Q-T Plateau showed high diversity and uniqueness of haplotypes. It is suggested that this region was the potential refugium of M. striata during the Quaternary glaciation, and that interglacial and postglacial range expansion occurred from this refugium. This scenario was in good agreement with the results of nested clade analysis, which inferred that the current spatial distribution of cpDNA haplotypes and populations resulted from range expansion, together with past allopatric fragmentation events. (c) 2008 The Linnean Society of London.

Characterization of photosynthetic pathway of plant species growing in the eastern Tibetan plateau using stable carbon isotope composition

The photosynthetic pathway of plant species collected at Menyuan, Henan, and Maduo sites, east of Tibetan Plateau, China, during the growing season were studied using stable carbon isotopes in leaves. The 232 samples leaves analyzed belonged to 161 species, 30 families, and 94 genera. The delta(13)C values (from -24.6 to -29.2 %o) indicated that all the considered species had a photosynthetic C-3 pathway. The absence of plant species with C-4 photosynthetic pathway might be due to the extremely low air temperature characterizing the Tibetan Plateau. The average delta(13)C value was significantly (p < 0.05) different between annuals and perennials at the three considered study sites. Hence the longer-lived species had greater water-use efficiency (WUE) than shorter-lived species, that is, longer-lived species are better adapted to the extreme environmental conditions of the Tibetan Plateau.

Reproductive ecology of the Qinghai-Tibet Plateau endemic Gentiana straminea (Gentianaceae), a hermaphrodite perennial characterized by herkogamy and dichogamy

The combined occurrence of both herkogamy and dichogamy in a hermaphrodite species has been considered to strongly favour outcrossing. In this study, we investigated in detail the reproductive ecology of Gentiana straminea Maxim. (Gentianaceae), a hermaphrodite perennial endemic to the Qinghai-Tibet Plateau. In a series of observations and experiments over four consecutive years, we examined whether the combination of dichogamy and herkogamy in individual flowers completely prevents geitonogamous pollen transfer in this species. The mode of floral development clearly indicates that autonomous self-pollination is completely avoided through herkogamy and dichogamy in individual flowers. This implication was confirmed by the breeding experiments, since no seed was produced when flowers were isolated. However, this gentian proved to be highly self-compatible when geitonogamous selfing was artificially induced. Many flowers opened simultaneously on individual plants, the ratio of male to female phase flowers was close to 2:1 in each inflorescence, at the full anthesis phase, and they were randomly distributed amongst the upper, middle and lower parts of each stem's inflorescence. On average, Bombus sushikini Skorikov, the most frequent visitor and only legitimate pollinator of G. straminea, visited nearly two flowers per inflorescence, and four flowers per plant. Among the pollinators' foraging bouts, the proportions of geitonogamous visits to inflorescences or flowers within an individual plant were 29% and 37%, respectively. Therefore, despite the strict dichogamous and herkogamous characteristics of the individual flowers, geitonogamous selfing might still prevail in G. straininea because of the size of its floral displays and the continuous visiting behavior of B. sushkini. (C) 2005 Elsevier SAS. All rights reserved.

基于卡尔曼滤波及牛顿预测的角加速度估计方法试验研究

基于角位置测量的角加速度实时估计问题是机电系统控制中一个非常重要的问题,在分析现有的线性回归平滑牛顿法和卡尔曼滤波法的基础上,提出了一种新的基于卡尔曼滤波和牛顿预测相结合的角加速度估计方法。该方法旨在利用牛顿预测进一步增强卡尔曼滤波的预测能力,减小由于滤波造成的相位滞后,提高估计加速度与实测加速度的一致性。为了验证新方法的有效性,以直接驱动机器人作为试验对象,采用将估计加速度的频率特性与实测加速度相比较的方法,分别对上述三种估计算法进行了试验比较研究,从而为利用估计加速度(取代测量加速度)实现加速度反馈控制提供了试验依据。

中国大陆地区远震体波接收函数与岩石圈厚度的研究

Movements of separation and convergence between the continental plates, as well as the interaction beween the lithosphere and asthenosphere is the dominant factor in plate evolution. Moreover, those phenomena, the formation, enrichment and storage of energy and mineral strorage, as well as intraplate earthquakes are all relate to plate movement and evolution. Therefore, the study of continental lithosphere, is not only helpful to analysing the dynamic model between lithosphere and asthenoshere as well as different plates, but also important to the nation's economy and the people's livelihood. And the lithospheric thickness or Lithosphere-Asthenosphere Boundary (LAB) is one of the most important parameters in study of continental lithospheric formation and evolution. Chinese continent composed by many small plates, possesses diverse type of lithospheric structure. But our knowledge ahout Chinese continental lithosphere, especially the regional research, is almost based on the low-resolution results of surface wave dispersion analysis and seismic wave tomography. Howere, recently a technique employing S-to-P converted body waves (the S receiver function technique) has been developed that can be used to identify the LAB with a higher resolution. This thesis has collected waveform data of 232 broadband seismic stations that are located in China and neighboring regions. Using teleseismic S-wave and P-wave receiver functions have studied the Chinese continental lithospheric structure. The results of this study indicate that, the thickness of Chinese continental lithosphere become thinner from west to east, and obvious difference exists between different blocks. Four types of lithosphere have been detected: (1) Convergence thicking lithosphere in Tibetan Plateau; (2) Stable lithosphere in Tarim basin and upper Yangtze craton; (4) Active lithosphere in Orogenic belts; (4) Break-up thinning lithosphere in east China craton

中国北方风成堆积的风化作用与环境变迁—U-Th、~(10)Be及元素地球化学的研究

The surface of the Earth is continuously undergoing changes as a result of weathering-erosion, plate tectonics and volcanic processes. Continental weathering-erosion with its complex rock-water interactions is the central process of global biochemical cycling of elements, and affects the long-term ocean atmosphere budget of carbon dioxide both through the consumption of carbonic acid during silicate weathering and through changes in the weathering and burial rates of organic carbon. Rates of the weathering-erosion depend on a variety of factors, in particular rock properties and chemical composition, climate (especially rainfall), structure, and elevation. They are quite variable on a regional scale. Thus, environmental changes in a region could be indicated by the history of weathering-erosion in the region. Recent attention has focused on increased silicate weathering of tectonically uplifted areas in the India-Asia collision zone as a possible cause for falling atmospheric CO_2 levels in the Cenozoic era. The wind blown dust deposits in the Loess Plateau is derived from the arid and semiarid regions in northwestern China, in turn, where the deposits have been derived from the Qinghai-Xizang Plateau and the high mountains around. Therefore, geochemistry of the wind blown loess-paleosol and red clay sequences may provide insight both to paleoenvironmental changes on the Loess Plateau, and to the uplift and weathering-erosion histories of the Qinghai-Xizang Plateau. In this paper, uranium-thorium series nuclides and cosmogenic ~(10)Be have been employed as tracers of weathering intensities and histories of the dust sediments in the Loess Plateau. Major elements, such as Na, Al, Fe etc., are also used to estimate degree of chemical alteration of the dust sediments and to rebuild the history of weathering on the Loess Plateau. First of all, using a low-level HPGe γ-ray detector, we measured U and Th series nuclides in 170 loess and paleosol samples from five sites in the Loess Plateau, going back 2.6 Ma. The results show that ~(238)U activities are disequilibrium with its daughter nuclide ~(230)Th in young loess-paleosol sequence, indicating that weathering was happened both in dust deposition site and in dust source regions. Using concentrations of ~(238)U and ~(232)Th in the samples, we estimated the amounts of ~(238)U leached out of from paleosols due to weathering. Further, based on analyses of ~(230)Th in paleosols deposited in the past ca. 140 ka, we determined when the paleosols weathered in the source regions. We conclude that most of the weathering in the dust-source regions may have occurred during the interglacials before dust deposition.

云南金顶超大型铅锌矿区镉的地球化学特征及其环境效应

云南金顶铅锌矿是镉元素富集区，采矿活动导致镉元素释放出来进入地表环境造成镉污染。矿区不同岩石中镉分布差异比较大，围岩中镉含量范围在50×10^-6-650×10^-6之间，平均310×10^-6，原生矿中镉含量范围14×10^-6-2800×10^-6，平均767×10^-6，氧化矿中镉含量范围110×10^-6-8200×10^-6，平均1661×10^-6，其平均值最高。氧化矿是镉元素的主要载体和释放源。淋滤实验表明矿石易氧化而释放出镉等有害元素，滤出元素可以迅速发生沉淀或被沉淀物包裹，其能力表现为Zn〉Pb〉Cd。研究结果表明，矿区下游江河段水体中隔的平均值为15.7μg/L，悬浮物中镉平均值为49.3 mg/kg，沉积物中镉平均值为203.7 mg/kg。矿区富镉岩石和矿物的自然风化是造成江水体和沉积物中镉污染的直接原因，对流域水生态环境造成潜在危害.

中国北方石墨矿床及赋矿孔达岩系碳同位素特征及有关问题讨论

本文综合了中国北方孔达岩系和石墨矿床的碳同位素数据102件, 发现片麻岩石墨n 透辉岩石墨< 大理岩石墨<石墨大理岩方解石< 大理岩方解石; 混合岩化岩石中石墨D13C 总介于有机碳和无机碳之间; 不同地体片麻岩石墨D13C 极为一致, 变化于- 22. 8‰～ - 21. 48‰, 略低于世界有机质平均值- 26 ±7‰; 大理岩的原岩碳酸盐D13C 高于2‰, 与2330～ 2060Ma期间全球性D13Ccarb 正向漂移事件一致。地质流体是碳同位素分馏、均一化的重要因素, 是石墨矿床的3种主要碳源之一, 是碳的5 种存在形式之一, 也是碳循环的重要媒介和方式; 导致热液矿床D13C= - 5‰左右的因素较多, 依据D13Ccalciteµ - 5‰得出成矿物质和流体来自地幔的结论值得怀疑; 中国北方孔达岩系形成于古元古代, 可能为2300～ 2050Ma。

多接收器等离子体质谱仪测钕同位素比值的质量歧视校正初探

利用国内首次引进的Nu Plasma型MC-ICPMS,对Nd同位素测试过程的质量歧视效应特征进行了研究.发现该类仪器测试过程的质量歧视效应并不完全符合指数函数,也不符合幂函数.质量歧视引起的同位素分馏随同位素对的平均质量数变化,但不严格遵从线性关系.只是在较小质量范围内呈近似线性关系.据此,用双分馏系数校正法可以获得143Nd/144Nd的校正系数,并用来校正143Nd/144Nd值.用此方法获得的JNdi-1的143Nd/144Nd值为O.512 107±O.OOO 008(2RSD),在测量误差范围内与TIMS测定值完全吻合.

滇东南老君山中——深变质岩系铅同位素特征及时代归属

滇东南老君山地区是我国重要的锡多金属成矿区之一，区内中－深变质岩系的时代归属尚存在不同认识。通过对其中的花岗片麻岩类的铜同位素研究，获得一岩－长石铅－铅等时线年龄为５９８±８４Ｍａ，（＾２０７Ｐｂ／＾２０４Ｐｂ）０＝１４．５２３±０．２３５，γ＝０．９７８９８，ＭＳＷＤ＝１４。这一年龄值代表了花岗片麻岩遭受混合岵化作用的年龄，相当于晚震旦世晚期。结合前人研究成果，本文认为该中－深变质岩系的时代归属

碳酸岩与铂族元素地球化学

碳酸岩（carbonatite）被视为一种研究大陆地幔地球化学的“探针岩石”，通过对这类岩石的研究，在探讨地幔组成与演化、地幔交代作用与不均一性以及岩浆形成的动力学背景、岩浆来源及演化和有关矿产的成矿作用等方面，具有重要的理论意义和实际价值。铂族元素（Platinum—group elements，简称PGE）在研究核-幔分异、地幔组成与演化以及幔源岩石（主要为基性-超基性岩）形成的大地构造背景、岩浆起源及演化，以及探讨K／T界线与陨石撞击事件等方面具有重要意义。本文在概述国内外碳酸岩和PGE地球化学研究现状的基础上，结合地质事实和地球化学研究成果，认为碳酸岩熔体具有一定携带PGE的能力，可利用PGE地球化学来探讨碳酸岩的源区特征和岩浆形成与演化过程；同时指出，碳酸岩PGE地球化学研究过程中还存在许多悬而未决的科学问题。

Coadsorption of nitric oxide and oxygen on the Ag(110) surface

The coadsorption of NO and O-2 on Ag(110) surface has been studied by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and in situ Raman spectroscopy. The existence of oxygen enhances the adsorption of NO by forming the NOx species, that is, NO2 and NO3, and the NO in turn as a promotor facilitates the cleavage of the dioxygen bond, forming the surface atomic oxygen species having the same spectral characteristics as those produced using oxygen at high pressure. The oxygen species generated by the interaction is composed of two parts. One is produced directly by the decomposition of surface NO-O-2 complex at ca 625 K, which raised an O 1s feature at 530.5 eV and is absent at ca 800 K, while the another with an O 1s binding energy of 529.2 eV emerges at higher temperatures and shows similar properties as the reported gamma-state oxygen which bound tightly on restructured silver surface. The exposure to NO and O-2 causes noticeable changes in the morphology of the Ag(110) surface and the flat terraces superseded by small (ca 0.1 mu m) pits, and particles with typical diameters of a few micrometres were formed at elevated temperatures. (C) 1999 Elsevier Science B.V. All rights reserved.

8～12岁男孩的性激素与智力、人格的关系

Recently there emerged more and more researhes concerning about sex hormone-related cognitive ability and behaviours. Few were carried out in pre- to early adolescent children., and the objective of the current study is to investigate whether there are covariance between sex hormones, intelligence and personality in 232 pre- to early adolescent boys, including 62 gifted boys. Indexes of sex hormone levels were salivary testosterone and estradiol concentrations, the 2D:4D digit ratio ( a reliable pointer of prenatal sex hormone concentraions). The Cattell Culture Fair Intelligence Test and a Chinese version of Children’s Personality Questionaire was applied in the current study. The main findings are: 1) salivary sex hormone concentrations significantly positively correlated with intelligence performance in 10-year-old boys; 2) salivary testosterone negatively related to intelligence performance in 12-year-old boys; 3) gifted boys bears lower testosterone concentrations in both prenatal period and pre- to early adolescence; 4) for personality, higher salivary estradiol was related to extraversion and digit ratios correlated with several personality factors in 8-year-old boys. In conclusion, results in the current study suggested that for male early maturers, intelligence may be negatively influenced by early coming androgen surge. In contrast, male late matures may benefit from their lately and moderately increasing hormone. Besides, the results suggested that the relationship between 2D:4D digit ratio and personality may also be paid attention to.