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Spatial associations of tree species in a subtropical evergreen broad-leaved forest

Journal of Plant Ecology 2012年第3期5卷 346-355页

作者： Zheng r.luo Ming J.Yu De l.Chen You G.Wu Bing Y.Ding Key laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life ScienceZhejiang UniversityHangzhou 310058China Management of Baishanzu Fengyangshan-Baishanzu National Nature ReserveQingyuan 323800China Department of Biology Science The School of Life and Environmental ScienceWenzhou UniversityWenzhou 325027China

Aims The spatial segregation hypothesis and the low-frequency hypothesis are two important proposed mechanisms that delay or prevent competitive exclusion in *** tree species interact with their neighbors,the importance of these potential processes can be investigated by analyzing the spatial structures of tree *** The distribution of the adults of 27 common tree species in a fully mapped 5-ha subtropical forest plot in Baishanzu,eastern China,was analyzed to investigate the community-level intra-and interspecific spatial association *** first tested for the overall spatial pattern in the 5-to 40-m neighborhoods and classified first-order bivariate associations with a diametric scheme based on ripley’s K and nearest-neighbor statistic(G-function).Then heterogeneous Poisson null models were used to distinguish second-order interactions from overall spatial associations(including first-order effects).Finally,we analyzed correlations between the existence of species interactions and some attributes of the species *** Findings Partial overlap and segregation increased with scale,whereas mixing *** 70%of the species pairs occurred less than expected at random,and only 3.4%of the species pairs were well mixed;11.0%of all species pairs showed significant small-scale interactions,which was a greater frequency than expected by chance if species are abundant or prefer the same habitat,but less frequent than expected if species are highly *** suggests that both spatial segregation and low frequency of species facilitate species coexistence by reducing the opportunity that trees of two species encounter each *** study also revealed that positive interactions were more prevalent than negative interactions in the forest,which indicates that positive interactions may have important effects on forest species assemblies.

关键词： Baishanzu point pattern analysis spatial segregation low frequency interaction opportunity

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动物源性食品中硝基呋喃类代谢物残留量检测方法的验证

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现代食品 2024年第7期30卷 173-179,183页

作者：吕婷邬杰刘鑫郭兰王建军李丹阳包头市农畜产品质量安全中心内蒙古包头014000

本文对《动物源性食品中硝基呋喃类药物代谢物残留量检测方法高效液相色谱/串联质谱法》(GB/T 21311—2007)进行方法验证。结果表明,1-氨基-乙内酰脲、5-吗啉甲基-3-氨基-2-噁唑烷基酮、3-氨基-2-噁唑酮、氨基脲这4种硝基呋喃类代谢物... 详细信息

本文对《动物源性食品中硝基呋喃类药物代谢物残留量检测方法高效液相色谱/串联质谱法》(GB/T 21311—2007)进行方法验证。结果表明,1-氨基-乙内酰脲、5-吗啉甲基-3-氨基-2-噁唑烷基酮、3-氨基-2-噁唑酮、氨基脲这4种硝基呋喃类代谢物在0.50~20.00 ng·ml^(-1)浓度范围内(内标浓度10 ng·ml^(-1))有良好的线性关系,相关系数> 0.99,平均回收率在98.6%~102.0%,相对标准偏差在0%~1.140%。该方法的灵敏度均满足标准方法中规定的要求。

关键词：硝基呋喃类代谢物高效液相色谱-串联质谱法方法验证

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role of quantum paths in generation of attosecond pulses

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Chinese Physics B 2020年第10期29卷 276-281页

作者： M r Sami A Shahbaz Department of Physics Government College UniversityP.O.Box 54000 LahorePakistan

We investigate the role of core potential in high ionization potential systems on high harmonic generation (HHG) spectra and obtain attosecond pulses. In our scheme, we use a standard soft core potential to model high ionization potential systems and irradiated these systems with fixed laser parameters. We observe the role of these systems on all the three steps involved in HHG process including ionization, propagation and recombination. In our study, the results illustrate that for high ionization potential systems, the HHG process is more sensitive to the ionization probability compared to the recombination amplitude. We also observe that due to the stronger core potential, small oscillations of the electrons during the propagation do not contribute to the HHG spectrum, which implies the dominance of only long quantum paths in the HHG spectrum. Our results, for attosecond pulse generation, show that long quantum path electrons are responsible for the supercontinuum region near the cutoff, which is suitable for the extraction of a single attosecond pulse in this region.

关键词： high-order harmonic generation attosecond pulses quantum paths strong nuclear potential

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笕麦冬

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分子植物育种 2024年第11期22卷 3833-3833页

作者：唐小清占春阳

笕麦冬(Ophiopogon japonicus),百合科(liliaceae)沿阶草属(Ophiopogon)多年生常绿草本植物,产于中国,原主产于浙江杭州笕桥一带,现浙江慈溪、余姚、萧山等地均有栽培。笕麦冬喜湿,喜温,常生长于林下、山坡以及草地等环境中。笕麦冬入...

笕麦冬(Ophiopogon japonicus),百合科(liliaceae)沿阶草属(Ophiopogon)多年生常绿草本植物,产于中国,原主产于浙江杭州笕桥一带,现浙江慈溪、余姚、萧山等地均有栽培。笕麦冬喜湿,喜温,常生长于林下、山坡以及草地等环境中。笕麦冬入药部位为其块根。药材表面黄白色或淡黄色,有细纵纹,呈纺锤形,断面黄白色,半透明。《本草述》记载,笕麦冬制药方式为:“去心捶扁极薄,晒干,加隔纸焙焦用。”

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Alloy solidification: Assessment and improvement of an easy-to-apply model

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Journal of Materials Science & Technology 2022年第35期130卷 1-11页

作者： H.liu Y.liu S.l.lu Y.Zhang H.Chen Y.Chen M.Qian School of Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China Centre for Additive Manufacturing School of EngineeringRMIT UniversityMelbourneVIC 3000Australia School of Materials Science and Engineering Sichuan UniversityChengdu 610065China

It has been a central task of solidification research to predict solute microsegregation. Apart from the lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation models has been proposed. However, the use of these models often requires essential experimental input information, e.g., the secondary dendrite arm spacing(λ), cooling rate( ˙T) or actual solidification range(△T). This requirement disables these models for alloy solidification with no measured values for λ,˙T and △T. Furthermore, not all of these required experimental data are easily obtainable. It is therefore highly desirable to have an easy-to-apply predictive model that is independent of experimental input,akin to the lever rule or Scheil-Gulliver model. Gong, Chen, and co-workers have recently proposed such a model, referred to as the Gong-Chen model, by averaging the solid fractions(f_(s)) of the lever rule and Scheil-Gulliver model as the actual solid fraction. We provide a systematic assessment of this model versus established solidification microsegregation models and address a latent deficiency of the model, i.e.,it allows the lever rule solid fraction fsto be greater than one(f_(s)> 1). It is shown that the Gong-Chen model can serve as a generic model for alloy solidification until fsreaches about 0.9, beyond which(f_(s)> 0.9) its applicability is dictated by both the equilibrium solute partition coefcient(k) and the solute diffusion coefcient in the solid(Ds), which has been tabulated in detail.

关键词： Solidification Microsegregation Solute Back diffusion Eutectic formation

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Modelling the role of ground-true riparian vegetation for providing regulating services in a Mediterranean watershed

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International Soil and Water Conservation research 2023年第1期11卷 159-168页

作者： Bruno A.Aparício João Pedro Nunes léonard Bernard-Jannin luis Filipe Dias Andre Fonseca Teresa Ferreira cE3c-Centre for Ecology Evolution and Environmental Changes&CHANGE-Global Change and Sustainability InstituteFaculty of SciencesUniversity of LisbonLisbonPortugal Forest research Centre&laboratory TErrA School of AgricultureUniversity of LisbonLisbonPortugal Soil Physics and land Management Group Wageningen University and ResearchWageningenNetherlands longline Environment ltd LondonUK

Intensive agricultural and industrial activities are often considered major sources of water ***,riparian vegetation(rV)is increasingly being promoted as a solution to balance the potentially adverse effects that agriculture may have on water ***,existing rV is often overlook in recent modelling efforts,failing to capture the current amount of ecosystem services ***,we used the Soil and Water Assessment Tool ecohydrological model to simulate the influence of ground-true rV on i)nutrient(nitrate and total phosphorus)and sediment exports from agricultural areas and ii)its effect for in-stream *** results are further compared against a set of hypothetical scenarios of different rV widths and different *** results point to a great rele-vance of existing rV in controlling in-stream concentration of sediments and nutrients where pressure from agriculture is highest,preventing them to surpass limits set in the EU Water Framework *** the other hand,in areas with industry discharges,the role of rV is limited and model results suggest that restoring rV would have limited *** illustrate how existing rV may already provide strong but not acknowledged water quality regulation services,how these services can differ substantially between nearby streams,and that effective strategies to improve water quality using rV must acknowledge existing patterns of vegetation,land use and contamination sources.

关键词： Agricultural pollution riparian vegetation Ecosystem services Hydrological services Mediterranean region

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Identification of suitable reference genes for quantitative gene expression analysis in clam Cyclina sinensis under salinity stress and Vibrio infection

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Journal of Oceanology and limnology 2023年第1期41卷 352-363页

作者： Fengjuan JIANG Qingyao WANG Jingjing DU Fu lÜ Qing NIE Weihong ZHAO College of Marine and Biological Engineering Yancheng Institute of TechnologyYancheng 224051China

The appropriate reference gene is a prerequisite for accurate normalization of gene expression level,and research on suitable reference genes in clam Cyclina sinensis is *** improve the situation,we selected five commonly used housekeeping genes,including β-actin,Elongation factor 1-α(EF1-α),Glyceraldehyde-3-pho sphate dehydrogenase(GAPDH),40S ribosomal protein S18(rPS18),and Tubulin a(TUB-α),then evaluated their expression stability in different adult tissues and under different experimental treatments(salinity stress and Vibrio parahaemolyticus infection).Their expression stability was analyzed by three frequently used programs,geNorm,NormFinder,and *** analysis indicated that multiple genes should be used for normalization,and we concluded that the reference gene combination GAPDH-rPS18-β-actin,should be used for qrT-PCr analysis in different tissues of *** under normal physiological *** the clams under salinity stress and Vibrio infection,EF1-α-GAPDHrPS18 was recommended as the gene combination for qrT-PCr ***-αwas generally poorly ranked by all programs,and should not be used in future *** study should provide fundamental support for accurate quantitative gene expression analysis of this species.

关键词： Cyclina sinensis reference gene different tissues salinity stress Vibrio infection

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A theory to link relationships of stand volume,density,mean diameter and height in forestry data

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Journal of Forestry research 2021年第1期32卷 15-20页

作者： Vladimir l.Gavrikov Chair of Ecology and Environmental Studies Institute Ecology and GeographySiberian Federal University79 pr.SvobodnyiKrasnoyarskRussian Federation 660041

In this study,a geometric model of a growing forest stand has been *** basic relationships considered link stand volume and stand density,diameter at breast height(DBH),mean DBH and mean *** model provides simple formulas connecting the exponents of all the *** of the formulas to real forestry data provided a high level of predictions of an exponent from two others measured through regressions from empirical *** Pinus sylvestris *** were of a static nature,a collection of individual stands,while the Pseudotsuga menziesii(Mirb.)Franco data were dynamic,representing forest stand development over *** ability of the model to predict exponents in the empirical data implies,on the one hand,a substantial level of similarity between the model and the forestry ***,on the other hand,the model gives an example in which parameters of one relationship may be linked to parameters of *** this kind of‘relationship between relationships’may be observed in forest stands undergoing active growth and competition-induced self-thinning.

关键词： relationship between relationships Selfthinning Forestry data Allometry Scots pine Douglasfir

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Extraterrestrial microspherules from Bajada del Diablo,Chubut,Argentina

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Geoscience Frontiers 2017年第1期8卷 137-149页

作者： M.J.Orgeira l.N.Castro G.A.Goldmann C.B.Prezzi E.Sileo D.r.Vega C.Franzosi r.D.Acevedo O.Martinez J.rabassa J.F.Ponce O.r.Tofalo Departamento de Ciencias Geologicas-lGEBA Facultaci de Ciencias Exactas y NaturalesOniversidad de Buenos AiresCiudad UniversitariaPabelldn 11C1428EHABuenos AiresArgentina Consejo Nacional de lnvestigaciones Cientificas y Tecnicas de Argentina CONICEE Argentina Departamento de lngenierfa Agrfcola y Uso de la Tierra Facultad de AgronomiaUniversidad de Buenos AiresAv.San Martin 4453CI417DSEBuenos AiresArgentina INQUIMAE Departamento de Qufmica Inorganica.Analitica y Quimica Fisica.Facultad de Ciencias Exactas y Naturales.Universidad de Buenos AiresPabellon IICiudad Universitaria.C1428EHABuenos Aires.Argentina Gerencia de lnvestigacion y Aplicaciones Comision Nacional de Energfa AtomicaUniversidad Nacional General San MartinBuenos AiresArgentina Centro Austral de lnvestigaciones Cientificas CADIC-ConicetUshuaiaArgentina Universidad Nacional de la Patagonia"San Juan Bosco"Sede Esquel ChubutArgentina Universidad Nacional de la Patagonia"San Juan Bosco"Sede Ushuaia UshuaiaArgentina

The Quaternary infilling of a circular structure located in Bajada del Diablo,Chubut Province,Argentina has been proposed as a crater strewn field in previous *** we report the finding of about 65 microspherules collected in a trench excavated in the center of the *** majority of handpicked specimens are single,but some of them exhibit compound *** single specimens are spherical with a mean size of 137 nm,whereas the more complex samples show peduncles and drop *** crystal growth is recognized in the internal structure of some broken *** chemical composition from the surface and center of microspherules was determined by energy dispersive spectrometry employing *** EMPA and XrD analysis indicate that the microspherules are mainly composed of Fe and O with magnetite,Fe0with subordinate *** consideration of possible anthropogenic and volcanic origins,these spherulites are ascribed to an extraterrestrial *** accumulation rate of 47 microspherules per m2/yr is estimated for the studied *** value is two orders of magnitude higher than the reference flux for cosmic dust estimated for the last 1 Ma in the Transantarctic *** microspherules might have been generated as a byproduct of asteroid entry in the atmosphere.

关键词： Extraterrestrial microspherules Chemistry Bajada del Diablo Chubut Patagonia-Argentina

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Impact of rainfed and irrigated agriculture systems on soil carbon stock under different climate scenarios in the semi-arid region of Brazil

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Journal of Arid land 2022年第4期14卷 359-373页

作者： André l CArVAlHO renato A ArAúJO-NETO Guilherme B lYrA Carlos E P CErrI Stoécio M F MAIA Center for Agrarian Sciences Federal University of AlagoasRio Largo 57072-900Brazil luiz de Queiroz College of Agriculture The University of Sao PauloPiracicaba 13418-900Brazil Federal Institute of Alagoas Marechal Deodoro 57160-000Brazil

Understanding the dynamics of soil organic carbon(SOC) is of fundamental importance in land use and management, whether in the current researches or in future scenarios of agriculture systems considering climate change. In order to evaluate SOC stock of the three districts(Delmiro Gouveia, Pariconha, and Inhapi districts) in the semi-arid region of Brazil in rainfed and irrigated agriculture systems under different climate scenarios using the Century model, we obtained rCP4.5 and rCP8.5 climate scenarios derived from the Eta regional Climate Model(Eta-Had GEM2-ES and Eta-MIrOC5) from the National Institute for Space research, and then input the data of bulk density, p H, soil texture, maximum temperature, minimum temperature, and rainfall into the soil and climate files of the Century model. The results of this study showed that the Eta-Had GEM2-ES model was effective in estimating air temperature in the future period. In rainfed agriculture system, SOC stock under the baseline scenario was lower than that under rCP4.5 and rCP8.5 climate scenarios, while in irrigated agriculture system, SOC stock in the almost all climate scenarios(rCP4.5 and rCP8.5) and models(Eta-Had GEM2-ES and Eta-MIrOC5) will increase by 2100. The results of this study will help producers in the semi-arid region of Brazil adopt specific agriculture systems aimed at mitigating greenhouse gas emissions.

关键词： soil carbon stock agriculture systems climate scenarios Century model semi-arid region

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