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Invasive weed disrupts facilitation of nutrient uptake in grass-clover assemblage

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Soil Ecology Letters 2024年第1期6卷 89-96页

作者： Wei Zhang Rick Muir Nicholas dickinson Faculty of Agriculture and Life Sciences Lincoln UniversityLincoln 7647New Zealand

Nutrient constraints in low-fertility soil were modified by different species ***-clover assemblages benefited both species in terms of nutrient *** of competition and facilitation is *** invasive weed removed essential nutrients from the grazing *** investigate the interplay of competition and facilitation between plants in low-fertility pasture grasslands of New Zealand,we compared nutrient uptake and acquisition of key nutrients of three species from different func-tional *** of Pilosella officinarum(mouse-eared hawk-weed,an invasive weed),Trifolium repens(white clover,a nitrogen fixer)and Dactylis glomerata(cocksfoot,a pasture grass)were planted into a soil with low-to-deficient concentrations of key *** yields were achieved by the grass growing alone but,when the clover and grass had grown together,there were complementary benefits in terms of procurement of a wide range of nutrients from soil despite lower root *** inva-sive weed negated these benefits,and soil nutrients were exploited less efficiently when Pilosella had grown alone or in a mixture with the other *** from the weed removed the benefits of grass-legume *** findings are interpreted to suggest that requirements for legumes to be the main source of nitrogen in pasture grasslands may be compromised unless competitive weeds are controlled to avoid disrupted procurement of key *** is likely these constraints to nutrient procurement would similarly impact conservation grasslands.

关键词： soil ferility facilitation species coexistence weed invasion legumes

Small RNA Pathways Are in the Angiosperm Male Present and Functional Gametophyte

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Molecular Plant 2009年第3期2卷 500-512页

作者： Robert Grant-Downton Said Hafidh David Twell Hugh G. dickinson Department of Plant Sciences South Parks Rd Oxford OX1 3RB UK Department of Biology University of Leicester University Road Leicester LE1 7RH UK

Small non-coding RNAs are essential for development of the sporophyte, the somatic diploid phase of flowering plants. They are integral to key cellular processes such as defense, generation of chromatin structure, and regulation of native gene expression. Surprisingly, very little is known of their presence and function in the male haploid phase of plant development （male gametophyte/pollen grain）, where dramatic cell fate changes leading to gametogenesis occur over just two mitotic divisions. We show that critical components of small RNA pathways are expressed throughout pollen development, but in a pattern that differs from the sporophyte. We also demonstrate that mature pollen accumulates a range of mature microRNAs, the class of small RNA most frequently involved in post-transcriptional regulation of endogenous gene expression. Significantly, these miRNAs cleave their target transcripts in developing pollen-a process that seemingly contributes to the purging of key regulatory transcripts from the mature pollen grain. Small RNAs are thus likely to make a hitherto unappreciated contribution to male gametophyte gene expression patterns, pollen development, and gametogenesis.

关键词： Pollen plant germline small RNA microRNA epigenetics

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没有一艘船能像一本书

疯狂英语（新读写） 2024年第3期 1-1页

作者： Emily dickinson 佚名(译) 不详

Effect of growing media and their constituents on fungus gnat, Bradysia sp, nr, coprophila （Lintner） adults

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Insect Science 2007年第6期14卷 467-475页

作者： RAYMOND A. CLOYD AMY dickinson RICHARD A. LARSON KAREN A. MARLEY Department of Entomology Kansas State University Manhattan Kansas Division of Biodiversity and Ecological Entomology Illinois Natural History Survey Champaign Illinois University of Illinois Department of Natural Resources and Environmental Sciences Urbana Illinois USA

This study was conducted to determine the attractiveness of two growing media, commonly utilized in greenhouses, to fungus gnat, Bradysia sp. nr. coprophila adults. The constituents of the most attractive growing medium tested were determined by gas chromatography analysis using a steam-distillation procedure. We found that fungus gnat adults were more attracted to the growing medium, SB300 Universal Professional Growing Mix, which contains composted bark, than to another growing medium （Sunshine LC1 Mix） and their components when tested in a series of laboratory experiments using multiple-choice experimental arenas. A higher percentage of fungus gnat adults were attracted to moist SB300 （92%） than SB300 growing medium that had been oven dried （8%）. In addition, fungus gnat adults preferred SB300 although they had been reared on Sunshine LC1 Mix. When comparing the SB300 fresh from the bag to growing medium that had been pasteurized and moistened with water, gas chromatographic-mass spectroscopic data showed there were declines in several terpenoid constituents as well as an increase in fatty acids and cyclosulfur. The results of this study indicate that B. sp. nr. coprophila adults prefer certain growing media, which may assist greenhouse producers in managing fungus gnats in crop production systems.

关键词： Attraction fungus gnats growing medium pest management preference,steam distillation

Analysis on the influence factors of Bitcoin’s price based on VEC model

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Financial Innovation 2017年第1期3卷 37-49页

作者： Yechen Zhu David dickinson Jianjun Li School of Finance Central University of Finance and EconomicsBeijing 100081China Department of Economics Birmingham Business SchoolUniversity of BirminghamBirmingham B152TTUK

Background:Bitcoin,the most innovate digital currency as of now,created since 2008,even through experienced its ups and downs,still keeps drawing attentions to all parts of *** relies on peer-to-peer network,achieved decentralization,anonymous and *** the most representative digital currency,people curious to study how Bitcoin’price changes in the ***:In this paper,we use monthly data from 2011 to 2016 to build a VEC model to exam how economic factors such as Custom price index,US dollar index,Dow jones industry average,Federal Funds Rate and gold price influence Bitcoin ***:From empirical analysis we find that all these variables do have a long-term *** dollar index is the biggest influence on Bitcoin price while gold price influence the ***:From our result,we conclude that for now Bitcoin can be treated as a speculative asset,however,it is far from being a proper credit currency.

关键词： Bitcoin price Gold price US dollar index VEC model

Global Community of Disaster Risk Reduction Scientists and Decision Makers Endorse a Science and Technology Partnership to Support the Implementation of the Sendai Framework for Disaster Risk Reduction 2015–2030

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International Journal of Disaster Risk Science 2016年第1期7卷 108-109页

作者： Chloe dickinson Amina Aitsi-Selmi Pedro Basabe Chadia Wannous Virginia Murray Public Health England United Nations Office for Disaster Risk Reduction the UNISDR Science and Technology Conference on the Implementation of the Sendai Framework for Disaster Risk Reduction 2015–2030 the UNISDR Scientific and Technical Advisory Group(STAG)

At the first gathering of its kind on the role of science in implementing the Sendai Framework for Disaster Risk Reduction 2015–2030,over 750 scientists,policymakers,business people,and practitioners met in Geneva from January 27–29,*** UNISDR Science and Technology Conference on the Implementation of the Sendai Framework for Disaster Risk Reduction 2015–2030 fea-

关键词： work Global Community of Disaster Risk Reduction Scientists and Decision Makers Endorse a Science and Technology Partnership to Support the Implementation of the Sendai Framework for Disaster Risk Reduction 2015

Asymptotic Marginal Tax Rate of Individual Income Tax in China

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Economic and Political Studies 2014年第2期2卷 121-138页

作者： ZHENYA LIU WU YANG DAVID dickinson the School of Finance Renmin University of China he Department of Economics University of Birmingham the School of International Trade and Economics Central University of Finance and Economics of China the Department of Economics University of Birmingham

This paper examines the asymptotic marginal rate of individual income tax which maximizes China's social welfare through numerical simulation based on the elasticity of China's labor supply, income distribution and the social objectives of redistribution in accordance with the optimal direct taxation theory. Taking advantage of the optimal direct taxation model with consideration of the income effect, it comes to the conclusion that combined with China's reality, the asymptotic marginal rate of individual labor income tax in China should be between 35% and 40%.

关键词： reform of individual income tax asymptotic marginal tax rate optimal direct taxation theory

How Does the Partitioning of Evapotranspiration and Runoff between Different Processes Affect the Variability and Predictability of Soil Moisture and Precipitation?

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Advances in Atmospheric Sciences 2003年第3期20卷 475-478页

作者： Robert E.dickinson Guiling WANG Xubin Zeng 曾庆存 Georgia Institute of Technology Atlanta GA Chinese Academy of Sciences Beijing 100080 University of Connecticut Storrs CT Chinese Academy of Sciences Beijing 100080 University of Arizona Tucson AZ Chinese Academy of Sciences Beijing 100080 Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100080

Water stored as part of the land surface is lost to evapotranspiration and runoff on different time scales, and the partitioning between these time scales is important for modeling soil water in a climate model. Different time scales are imposed on evapotranspiration primarily because it is derived from different reservoirs with different storage capacities, from the very rapid evaporation of canopy stores to the slow removal by transpiration of rooting zone soil moisture. Runoff likewise ranges in time scale from rapid surface terms to the slower base-flow. The longest time scale losses of water determine the slow variation of soil moisture and hence the longer time scale effects of soil moisture on precipitation. This paper shows with a simple analysis how shifting the partitioning of evapotranspiration between the different reservoirs affects the variability of soil moisture and precipitation. In particular, it is concluded that a shift to shorter time scale reservoirs shifts the variance of precipitation from that which is potentially predictable to unpredictable.

关键词： evapotranspiration climate model land surface coupling

Characteristics of Anthropogenic Sulfate and Carbonaceous Aerosols over East Asia: Regional Modeling and Observation

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Advances in Atmospheric Sciences 2008年第6期25卷 946-959页

作者： Yan HUANG William L. CHAMEIDES Qian TAN Robert E. dickinson School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta GA 30332 Nicholas School of the Environment and Earth Sciences Duke University Durham NC 27708 Goddard Earth Sciences and Technology Center University of Maryland Baltimore MD 21228

The authors present spatial and temporal characteristics of anthropogenic sulfate and carbonaceous aerosols over East Asia using a 3-D coupled regional climate-chemistry-aerosol model, and compare the simulation with the limited aerosol observations over the region. The aerosol module consists of SO2, SO4^2-, hydrophobic and hydrophilic black carbon （BC） and organic carbon compounds （OC）, including emission, advections, dry and wet deposition, and chemical production and conversion. The simulated patterns of SO2 are closely tied to its emission rate, with sharp gradients between the highly polluted regions and more rural areas. Chemical conversion （especially in the aqueous phase） and dry deposition remove 60% and 30% of the total SO2 emission, respectively. The SO4^2- shows less horizontal gradient and seasonality than SO2, with wet deposition （60%） and export （27%） being two major sinks. Carbonaceous aerosols are spatially smoother than sulfur species. The aging process transforms more than 80% of hydrophobic BC and OC to hydrophilic components, which are removed by wet deposition （60%） and export （30%）. The simulated spatial and seasonal SO4^2-, BC and OC aerosol concentrations and total aerosol optical depth are generally consistent with the observations in rural areas over East Asia, with lower bias in simulated OC aerosols, likely due to the underestimation of anthropogenic OC emissions and missing treatment of secondary organic carbon. The results suggest that our model is a useful tool for characterizing the anthropogenic aerosol cycle and for assessing its potential climatic and environmental effects in future studies.

关键词： regional climate modeling anthropogenic emission sulfate aerosol black carbon and organic carbon East Asia