12 resultados para Murray Meteorite

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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冷杉属是松科中的第二大属,在北半球有着广泛的分布区,从温带的高纬度地带到亚热带(偶达热带地区)的山地,呈间断不连续的分布。虽然一些学者曾对冷杉属进行过大量的分类学和系统学研究,但该属复杂的变异式样至今仍困扰着植物系统学家们。本论文是在腊叶标本和野外实地调查的基础上,从形态学、解剖学、分子系统学和植物地理学等方面进行分类学和系统发育的分析研究。现得到以下初步结果。1.对冷杉属叶角质层内表面胞间凸缘的研究结果表明,可以分为4种类型: 1. 弯曲且发达的单凸缘;2直且发达的单凸缘;3不发达的单凸缘;4双桥型凸缘。分布于欧洲和亚洲的绝大部分种类都是弯曲且发达的单凸缘类型(日本一种除外),而分布于北美的种类则具有四种不同的类型。 2. 叶横切面的研究结果表明皮下层细胞的发育状况和树脂道的位置与大小在Sect. Balsamea中稳定,皮下层细胞的缺失和不发育、树脂道大且中生在该属中可能反映原始状态。 3. 本研究首次发现nrDNA ITS的长度在属下有较大的变异,变异幅度1700 bp-2500 bp,分析得出引起这一变异的主要原因是由于ITS1中有以GGCCACCCTAGTC为核心数目不等的重复序列的存在,并讨论了ITS长度的变异在冷杉属和松科系统演化中的意义。 4. nrDNA ITS的RFLP分析结果和5种冷杉的ITS序列分析结果(以Keteleeria davidiana为外类群)表明A. bracteata与Sect. Balsamea总是聚在一起,亲缘最近;A. kawakamii应属于Sect. Momi。 5. 地理分布和系统发育分析的研究结果表明,冷杉属的多样性中心在北美西南部、而种类分布最大多的地区为东亚、种群分化最强烈的地区为我国的横断山脉。根据冷杉属的系统发育、化石资料和现代冷杉属的地理分布格局,冷杉属可能起源于白垩纪的高纬度地带。 6. 结合ITS RFLP和ITS序列的分支分析结果以及某些形态特征和地理分布资料,重建属下分类系统,将冷杉属分为8组2亚组。探讨了各组间的亲缘关系,认为Sect. Balsamea是冷杉属中的原始类群,Sect. Balsamea是与Sect. Balsamea亲缘最近,形态上十分特化的类群。来自ITS的分析结果为摒属下亚属的划分和将A. kawakamii自Sect. Balsamea中移出,放入Sect. Momi中提供了强有力的证据。经过标本和文献考证,综合各方面的资料,本文对冷杉属进行了全面系统的分类学修订,包括44种17变种1亚种,系统排列如下: 组1. 树脂冷杉组Sect. 1. Balsamea Engelmann。该组包括8种4变种:Abies balsamea, A. lasiocarpa, A. sibirica, A. sachalinensis, A. fraseri, A. koreana, A. nephrolepis, A. veitchii, A. bracteata。 组3. 日本冷杉组Sect. 3. Momi Franco。 亚组1.日本冷杉亚组Subsect. 1. Firmae (Franco) Farjon et Rushforth。该亚组包括6种3变种:A.holophylla, A. homolepis, A. firma, A. beshanzuensis, A. chensiensis, A. pindrow, A. beshanzuensis var. ziyuanensis, A. chensiensis var. ernestii, A. chensiensis var. salouenensis。 亚组2. 鳞皮冷杉亚组Subsect. 2. Squamatae E. Murray。该亚组包括12种6变种:A squamata, A. delavayi, A. nukiangensis, A. recurvata, A. spectabilis, A. mariesii, A. kawakamii, A. forrestii, A. fargesii, A. fansipanensis, A. fanjingshanensis, A. yuanbaoshanensis, A. delavayi var. fabri, A. delavayi var. motuoensis, A. spectabilis var. densa, A. forrestii var. georgei, A. forrestii var. ferreana, A. fargesii var. faxoniana。 组4. 冷杉组Sect. 4. Abies。该组包括7种1变种1亚种:A. alba, A. cephalonica, A. nordmanniana, A. nebrodensis, A. cilicica, A. pinsapo, A. numidica, A. nordamanniana ssp. equitrojani, A. pinsapo var. marocana。 组5. 太平洋冷杉组成Sect. 5. Amabiles (Matzenko) Farjon et Rushforth。该组仅一种:A. amabilis。 组6. 高贵冷杉组Sect. 6. Nobilis Engelmann。该组有2种1变种:A. procera, A. magnifica, A. magnifica var. shastensis。 组7. 大冷杉组成Sect. 7. Grandes Engelmann, emend. Farjon et Rushforth。该组包括4种2变种:A. concolor, A. grandis, A. durangensis, A. guatemalensis, A. concolor var. lowiana, A. durangensis var. coahuilensis。 组8. 墨西哥冷杉组Sect. 8. Oiamel Franco, emend. Farjon et Rushforth。该组包括A. religiosa, A. vejarii, A. vejari var. mexicana, A. hickelii

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1. The stripe-backed weasel Mustela strigidorsa is one of the rarest and least-known mustelids in the world. Its phylogenetic relationships with other Mustela species remain controversial, though several unique morphological features distinguish it from congeners. 2. It probably lives mainly in evergreen forests in hills and mountains, but has also been recorded from plains forest, dense scrub, secondary forest, grassland and farmland. Known sites range in altitude from 90 m to 2500 m. Data are insufficient to distinguish between habitat and altitudes which support populations, and those where only dispersing animals may occur. 3. It has been confirmed from many localities in north-east India, north and central Myanmar, south China, north Thailand, north and central Laos, and north and central Vietnam. Given the limited survey effort, the number of recent records shows that the species is not as rare as hitherto believed. Neither specific nor urgent conservation needs are apparent.

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A radial basis function neural network was employed to model the abundance of cyanobacteria. The trained network could predict the populations of two bloom forming algal taxa with high accuracy, Nostocales spp. and Anabaena spp., in the River Darling, Australia. To elucidate the population dynamics for both Nostocales spp. and Anabaena spp., sensitivity analysis was performed with the following results. Total Kjeldahl nitrogen had a very strong influence on the abundance of the two algal taxa, electrical conductivity had a very strong negative relationship with the population of the two algal species, and flow was identified as one dominant factor influencing algal blooms after a scatter plot revealed that high flow could significantly reduce the algal biomass for both Nostocales spp. and Anabaena spp. Other variables such as turbidity, color, and pH were less important in determining the abundance and succession of the algal blooms.

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This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species.

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The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed. (C) 2008 Elsevier Ltd. All rights reserved.

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The main research projects reported in this paper are the establishment of a luminescence (OSL/TL) dating laboratory in The Institute of Geology and Geophysics, CAS, and studies on OSL dating technique and protocol of sediments from North China. These projects have been suggested in order to fit in with the needs of research developments in environmental changes, in particular the aridity and desertification in North China. A new luminescence dating laboratory in which there are a Rise TL/OSL-DA-15B/C reader with Sr-90 beta source, a set of Little More Tape 9022 alpha and beta irradiators, three set of Daybreak 583 intelligent alpha counters and sample preparation system has been set up in the Institute in June 2001. The courses of the establishment of a new laboratory involved a series of technical works, besides making a suitable choice of the equipment, as follows: installing and testing TL/OSL reader, calibrating the dose rate of the beta and alpha sources in the irradiators with the standard sources, testing and calibrating the count rates of the thick source alpha counting in the alpha counters with a standard sample, and then dating of the know age samples to check and examine the OSL/TL dating system. All data obtained from above calibrations and tests show that the established OSL/TL system, including the used equipment in it, can be used to determine age of the geological and archaeological samples with an error of equivalent dose (De) of less than 5%. The OSL dates of several sediment samples obtained from the system are good agreement with those from the OSL dating laboratory in Hong Kong University and ~(14)C dates within 1 - 2 standard deviations. The studies on OSL dating technique and protocol of sediment samples being in progress involve the De determinations with single aliquot regeneration (SAR) (Murray and Wintle, 2000) of the coarse grain quartz from sand dune samples and comparison of the De determinations obtained from SAR with those measured by using multiple aliquot regeneration of loess fine grains. The preliminary results from these research works are shown as follows. The very low natural equivalent dose (De) of about 0.012 - 0.03 Gy, corresponding age of less than 10 years, for BLSL (blue light stimulated luminescence) of the coarse grain quartz from modern sand dune samples in Horqin sand fields has been determined with both the SAR and multiple aliquot regeneration (MAR) techniques. This imply that the BLSL signal zeroing of the quartz could be reached before burying of the sand in Horqin sand fields. The De values and ages of the coarse grain quartz measured with SAR protocol are in good agreement with those obtained from multiple aliquot technique for the modern sand dune samples, but the errors of De from the MAR is greater than those from the SAR. This may imply that the higher precision of age determination for younger sand dune samples could be achieved with the SAR of coarse grain quartz. The MAR combining with "Australian Slide method" may be a perfect choice for De measurements of loess fine grain samples on the basis of analysis of De values obtained from the SAR and from the MAR. The former can be employed to obtain a reliable age estimate of loess sample as older as approximately SO ka BR There is a great difference between De determinations from the (post-IR) OSL of the SAR (Roberts and Wintle, 2001) and those from independent or expected estimates for the older samples. However, the age estimates obtained from the (post-IR) OSL of the SAR are mostly closed to the independent age determinations for the younger (age less than 10 ka) fine grain samples. It may be suggested that the (post-IR) OSL of the SAR protocol of the fine grain fraction would be a suitable choice to dating of the younger samples, but may be unsuitable for the older samples.

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Describing visually space-time properties of geological phenomena consists of one of the most important parts in geology research. Such visual images are of usually helpful for analyzing geological phenomena and for discovering the regulations behind geological phenomena. This report studies mainly three application problems of scientific visualization in geology: (Dvisualizing geological body A new geometric modeling technique with trimmed surface patches has been eveloped to visualize geological body. Constructional surfaces are represented as trimmed surfaces and a constructional solid is represented by the upper and lower surface composed of trimmed surface patches from constructional surfaces. The technique can completely and definitely represent the structure of geological body. It has been applied in visualization for the coal deposit in Huolinhe, the aquifer thermal energy storage in Tianjin and the structure of meteorite impact in Cangshan et al. (2)visualizing geological space field Efficient visualization methods have been discussed. Marching-Cube algorithm used has been improved and is used to extract iso~surface from 3D data set, iso-line from 2D data set and iso-point from ID data set. The improved method has been used to visualize distribution and evolution of the abnormal pressures in Zhungaer Basin. (3)visualizing porous space a novel way was proposed to define distance from any point to a convex set. Thus a convex set skeleton-based implicit surface modeling technique is developed and used to construct a simplified porous space model. A Buoyancy Percolation numerical simulation platform has been developed to simulate the process of migration of oil in the porous media saturated with water.

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Chinese National Antarctic Research Expedition (CHTNARE) has collected 4480 meteorite specimens in the Grove Mountains, East Antarctica, from 1998 to 2003. According to the location characteristics and the diversity of the classification, the paper concludes that the Grove Mountains is another important meteorite concentration area in the Antarctica. The Concentration mechanisms at the site could be related to the last glacier activity and katabatic wind. An empirical model was proposed: 1) Probably during the Last Glacial Maximum, ice flow overrided the Gale Escarpment range in the area. Formerly concentrated meteorites were carried by the new glacier and stayed in the terminal moraine when the glacier retreated. 2) Blown by strong katabatic wind, Newly exposed meteorites on the ablation zone were scattered on the blue ice at the lee side of the Gale escarpment. Some of them would be buried when they were moved further onto the firn snow zone. Many floating meteorites stopped and mustered at the fringe of the moraine. The chemical-petrographic of 31 meteorites were assigned based on electron probe microanalyses, petrography and mineralogy, including 1 martian lherzolitic shergottite, 1 eucrite, 1 extreme fine grain octahedron iron meteorite, and 28 ordinary chondrites (the chemical groups: 7 H-group, 13 L-group, 6 LL-group, 2 L/LL group; the petrographic types: 6 unequilibrated type 3 and 22 equilibrated type 4-6). GRV99028 meteorite has the komatiite-like spinifex texture consisting of acicular olivine crystals and some hornblende-family minerals in the interstitial region. Possibly it has crystallized from a supercooled, impact-generated, ultramafic melt of the host chondrite, then experienced the retrogressive metamorphism. Four typical chondrule textures were studied: porphyritic texture, radiative texture, barred texture and glass texture. The minerals are characteristically enriched in MgO content.