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矿物学报 2015年第S1期35卷 667-页

作者：刘琪刘耘中国科学院地球化学研究所矿床地球化学国家重点实验室贵州贵阳550081

clumped"同位素指同位素体中含有两个或两个以上稀有同位素的情况(Eiler,2007)。就目前而言,其主要的研究形式是针对碳酸盐矿物中13C与18O相成键的同位素个体,使用高分辨率气相质谱技术来测定其浓度进而反推古温度,从而在地质温度领域... 详细信息

clumped"同位素指同位素体中含有两个或两个以上稀有同位素的情况(Eiler,2007)。就目前而言,其主要的研究形式是针对碳酸盐矿物中13C与18O相成键的同位素个体,使用高分辨率气相质谱技术来测定其浓度进而反推古温度,从而在地质温度领域打开了单一矿物相测温的新篇章。"clumped"同位素地质温度计区别于传统同位素地质测温的特性在于其只需测定单一物质便可重建地质温度,而不需要了解该碳酸盐形成过程中与其平衡的水的同位素信息。自碳酸盐"clumped

关键词：碳酸盐矿物 clumped 同位素效应质测研究形式高分辨率气候重建成键矿物相质谱技术

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Aggregated seed arrival alters plant diversity in grassland communities

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Journal of Plant Ecology 2014年第1期7卷 51-58页

作者： Gregory R.Houseman Department of Biological Sciences Wichita State University1845 FairmountWichitaKS 67260USA

Aims Species aggregation is commonly seen in plant communities and may increase diversity by causing intraspecific competition to exceed interspecific *** potential source of this spatial aggregation is seed dispersal but it is unclear to what extent aggregated seed distributions affect plant diversity in real *** a field experiment,I tested whether uniform or aggregated seed arrival alters community structure and whether these effects vary with sowing *** The experiment consisted of two spatial seeding treatments(uniform and aggregated)that were fully crossed with three seed density ***,3×4-m plots were arrayed in a low-diversity grassland located in Kansas,*** plot was divided into fortyeight,0.5×0.5-m *** aggregated seeding treatments,each of the 15 species was sown into three randomly selected patches within the plot(3×15=45).To create a uniform species arrival but control for the seed addition method,all 15 species were sown into 45 individual patches(with three patches remaining unsown)within each *** mass for each species was held constant at the plot scale between uniform or aggregated treatments within a given level of the sowing density *** two growing seasons,plant density was quantified for all sown species in 15 randomly selected patches from each *** Findings I found evidence for shifts in community structure in response to the different spatial seeding *** evenness of added species was higher under aggregated than uniform sowing *** was no detectable effect of aggregated seed sowing on species richness at 3.75 m^(2) ***,when species richness was extrapolated to larger scales(11.25 m^(2)),aggregated sowing was predicted to have greater richness than uniform *** of seed aggregation on community structure were apparent only at moderate to high sowing rates,yet the latter are within the range of measured seed dispersal in s

关键词： clumped colonization rank-abundance distributions seed dispersal seed sowing

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13C-18O Bonds in Precipitated Calcite and Aragonite: An ab InitioStudy

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Open Journal of Geology 2014年第9期4卷 436-480页

作者： Jie Yuan Zhigang Zhang Yigang Zhang Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Science Beijing China

The 13C-18O bonds in carbonates are potential single-phase geo-thermometers. However, their theoretical distributions (noted as Δ47s) in CO2 degassed from calcite and aragonite with phosphoric acid are unclear. Thus, the isotope reactions of 13C-18O bonds on the growing surfaces of calcite (0001) and aragonite (001) planes were investigated using ab initio techniques. It was found that these reactions determined 13C-18O clumped isotope signatures in bulk calcite and aragonite minerals with novel Δ47 polynomials: and for temperatures ranging from 260 to 1500 K. These theoretical results were in good agreement with the experimental data. In addition, the influence of phosphoric acid on these polynomials was at the level of 0.01‰.

关键词： 13C-18O Bonds clumped Isotope Calcite and Aragonite ab Initio Calculation

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Aqueous Extracts of Dried Fruits of Zanthoxylum armatumDC., (Rutaceae) Induce Cellular and Nuclear Damage Coupled with Inhibition of Mitotic Activity in Vivo

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American Journal of Plant Sciences 2012年第11期3卷 1646-1653页

作者： Eros Vasil Kharshiing Department of Botany St. Edmund’s College Shillong India.

Bioactive compounds derived from plant natural compounds have proven to be valuable sources of metabolites which can seldom be obtained from other sources. Plants belonging to the genus Zanthoxylum have been valued across various cultures for their curative properties. Zanthoxylum armatum DC., belonging to the family Rutaceae is extensively used in traditional practices in North-Eastern India and neighbouring regions including South-East Asia. However, the potential cytogenetic effects of Zanthoxylum armatum under in vivo conditions, and their causative mechanisms have not yet been studied in detail. The current study was undertaken to evaluate the cytotoxic and genotoxic potential of aqueous extracts of fruits of Z. armatum under in vivo conditions using the Allium test. Physiological and cellular data indicate that the extracts induce clumped chromosomes at metaphase stage of cell division coupled with mitotic arrest. Electron microscopy data reveal membrane damage of cellular organelles, chromatin condensation and chromatin marginalisation in cell of roots incubated in the extracts. The extracts also induce concentration dependent protein precipitation and genomic DNA degradation.

关键词： clumped Chromosomes Chromatin Condensation and Marginalisation TEM Toxicity Zanthoxylum armatum

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