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成熟的种子到哪里去了?——评述“Seed Fates:Seed predation,Seed Dispersal and Seedling Establishment”一书
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作者 肖治术 《植物生态学报》 CAS CSCD 北大核心 2005年第3期519-519,共1页
关键词 《Seed fates: SEED predation Seed Dispersal and SEEDLING Establishment》 书评 食果动物 种子扩散 CAB International Publishing出版社
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Different Cultures and Different Fates—On Cultural Meanings of “Bluest Eye” in Morrison'sThe Bluest Eye
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作者 周凌敏 《海外英语》 2013年第21期248-249,共2页
The Bluest Eye is Toni Morrison’s first novel.After its publication,it receives many criticisms.This article aims to ana lyze Pecola and Claudia’s understandings about black culture,then to clarify that different in... The Bluest Eye is Toni Morrison’s first novel.After its publication,it receives many criticisms.This article aims to ana lyze Pecola and Claudia’s understandings about black culture,then to clarify that different interpretations of the very name"the bluest eye"lead to different fates.With different visions of the black heritage,Pecola and Claudia have different perception of the world and thus have widely divergent outcomes in the painful circumstances. 展开更多
关键词 The bluest eye Pecola Claudia BLUES BLACK HERITAGE
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A Comparative Study on Different Fates between Jane Eyre and Lin Daiyu
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作者 林冬梅 赵慧 《海外英语》 2014年第7X期185-186,共2页
Jane Eyre and A Dream of Red Mansions can be regarded as the most famous two classics in the history of literature.In A Dream of Red Mansions,Cao Xueqin exhausted almost all his heart and soul to portray the character... Jane Eyre and A Dream of Red Mansions can be regarded as the most famous two classics in the history of literature.In A Dream of Red Mansions,Cao Xueqin exhausted almost all his heart and soul to portray the character─Lin Daiyu,whose tragic and impressive love story has moved thousands of readers into tears.While,Charlotte Bronte’s Jane Eyre raised heated discussion in 19th century because of the vivid and energetic female she depicted in her book.By comparison,it is easy to find that there are some similarities between the two characters.However,their fates are quite different.This paper tries to make a comparison between Jane Eyre and Lin Daiyu,review their life experience,analyze possible reasons that may account for the different fates,and draw a conclusion.Hope that this paper can do some help to those who are interested in literature home and abroad. 展开更多
关键词 LIN Daiyu JANE EYRE fate comparison
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Where Is Happiness?——Brief Analysis of the Differences of Elizabeth and Gu Manlu that Leading to Their Different Fates
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作者 韩玉倩 《海外英语》 2015年第10期163-164,共2页
Both Jane Austen and Eileen Chang are popular female writers.However they endowed their heroines with differentfates:Elizabeth in Pride and Prejudice earns a happily-ever-after with her Mr.Right,while Gu Manlu in Eigh... Both Jane Austen and Eileen Chang are popular female writers.However they endowed their heroines with differentfates:Elizabeth in Pride and Prejudice earns a happily-ever-after with her Mr.Right,while Gu Manlu in Eighteen Springs has toembrace death long before her time.They are destined due to their different family backgrounds and different characters which aredepicted in the novels. 展开更多
关键词 DIFFERENT fates DIFFERENT family BACKGROUNDS DIFFERENT CHARACTERS
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Soxllb regulates the migration and fate determination of Müller glia-derived progenitors during retina regeneration in zebrafish 被引量:4
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作者 Kaida Song Zihao Lin +5 位作者 Lining Cao Bowen Lu Yuxi Chen Shuqiang Zhang Jianfeng Lu Hui Xu 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第2期445-450,共6页
The transcription factor Sox11 plays important roles in retinal neurogenesis during vertebrate eye development.However,its function in retina regeneration remains elusive.Here we report that Sox11 b,a zebrafish Sox11 ... The transcription factor Sox11 plays important roles in retinal neurogenesis during vertebrate eye development.However,its function in retina regeneration remains elusive.Here we report that Sox11 b,a zebrafish Sox11 homolog,regulates the migration and fate determination of Müller glia-derived progenitors(MGPCs)in an adult zebrafish model of mechanical retinal injury.Following a stab injury,the expression of Sox11 b was induced in proliferating MGPCs in the retina.Sox11 b knockdown did not affect MGPC formation at 4 days post-injury,although the nuclear morphology and subsequent radial migration of MGPCs were alte red.At 7 days post-injury,Sox11 b knockdown res ulted in an increased proportion of MGPCs in the inner retina and a decreased propo rtion of MGPCs in the outer nuclear layer,compared with controls.Furthermore,Sox11 b knockdown led to reduced photoreceptor regeneration,while it increased the numbe rs of newborn amacrines and retinal ganglion cells.Finally,quantitative polymerase chain reaction analysis revealed that Sox11 b regulated the expression of Notch signaling components in the retina,and Notch inhibition partially recapitulated the Sox11 b knockdown phenotype,indicating that Notch signaling functions downstream of Sox11 b.Our findings imply that Sox11 b plays key roles in MGPC migration and fate determination during retina regeneration in zebrafish,which may have critical im plications for future explorations of retinal repair in mammals. 展开更多
关键词 cell migration fate determination Müllerglia Müller glia-derived progenitor Notch signaling photoreceptor retina regeneration Sox11 transcription factor ZEBRAFISH
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A Comparative Analysis of Causes of Tom's and Eliza's Different Fates in Uncle Tom's Cabin
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作者 LIU Xi WU Yi 《Journal of Literature and Art Studies》 2015年第11期1030-1034,共5页
Since African-Americans were transported to America, more than three hundred years have passed. During the tragic and bitter period of time, African-Americans never stopped their efforts to achieve their freedom. Thro... Since African-Americans were transported to America, more than three hundred years have passed. During the tragic and bitter period of time, African-Americans never stopped their efforts to achieve their freedom. Through the description of two kinds of heroines, Uncle Tom and Eliza, Harriet Beecher Stowe tells us: Tom, who was resigned to bad conditions, obedient to the slave-owner, was doomed to death while Eliza who dared to revolt slavery gained a new life and freedom. To some extent, Uncle Tom's Cabin played an active function to advance social development, especially in the movement of abolitionist and the American Civil War. The present paper focuses on the analysis of the causes of the different fates belonging to Tom and Eliza respectively from the perspectives of the external cause and internal cause and their own characters. 展开更多
关键词 CAUSE SLAVERY CHARACTER fate
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Fate of Parent and Substituted Polycyclic Aromatic Hydrocarbons in SBR/MBBR Treatment Process:Experimental Value Against Model Prediction
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作者 ZHAO Jing TIAN Weijun +3 位作者 LIU Shuhui QIAO Kaili DU Zhaoyang XIE Wenlong 《Journal of Ocean University of China》 SCIE CAS CSCD 2023年第2期479-489,共11页
The knowledge of the existence,distribution and fate of polycyclic aromatic hydrocarbons(PAHs)and substituted polycyclic aromatic hydrocarbons(SPAHs)in wastewater treatment plants(WWTPs)was vital for reducing their co... The knowledge of the existence,distribution and fate of polycyclic aromatic hydrocarbons(PAHs)and substituted polycyclic aromatic hydrocarbons(SPAHs)in wastewater treatment plants(WWTPs)was vital for reducing their concentrations entering the aquatic environment.The concentrations of 13 SPAHs and 16 PAHs were all determined in a WWTP with styrene butadiene rubber(SBR)in partnership with the moving bed biofilm reactor(MBBR)process.SPAHs presented a higher concentration lever than PAHs in nearly all samples.The total removal efficiencies of PAHs and SPAHs ranged from 64.0%to 71.36%and 78.4%to 79.7%,respectively.The total yearly loads of PAHs(43.0 kg)and SPAHs(73.0 kg)were mainly reduced by the primary and SBR/MBBR biological treatment stages.The tertiary treatment stage had a minor contribution to target compounds removal.According to a synthesis and improvement fate model,we found that the dominant processes changed as the chemical octanol water partition coefficient(K_(ow))increased.But the seasonal variations of experimental removal efficiencies were more obvious than that of predicted data.In the primary sedimentation tank,dissolution in the aqueous phase and sorption to sludge/particulate matter were controlling processes for the removal of PAHs and SPAHs.The sorption to sludge and biodegradation were the principal removal mechanisms during the SBR/MBBR biological treatment process.The contribution of volatilization to removal was always insignificant.Furthermore,the basic physicochemical properties and operating parameters influenced the fate of PAHs and SPAHs in the WWTP. 展开更多
关键词 substituted polycyclic aromatic hydrocarbons moving bed biofilm reactor removal efficiency fate process model
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Fate of fertilizer nitrogen and residual nitrogen in paddy soil in Northeast China
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作者 BI Shi-ting LUO Xiang-yu +4 位作者 ZHANG Chen LI Peng-fei YU Cai-lian LIU Zhi-lei PENG Xian-long 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第11期3535-3548,共14页
The relationship between the fate of nitrogen (N) fertilizer and the N application rate in paddy fields in Northeast China is unclear,as is the fate of residual N.To clarify these issues,paddy field and15N microplot e... The relationship between the fate of nitrogen (N) fertilizer and the N application rate in paddy fields in Northeast China is unclear,as is the fate of residual N.To clarify these issues,paddy field and15N microplot experiments were carried out in 2017 and 2018,with N applications at five levels:0,75,105,135 and 165 kg N ha–1(N0,N75,N105,N135 and N165,respectively).15N-labeled urea was applied to the microplots in 2017,and the same amount of unlabeled urea was applied in 2018.Ammonia (NH3) volatilization,leaching,surface runoff,rice yield,the N contents and15N abundances of both plants and soil were analyzed.The results indicated a linear platform model for rice yield and the application rate of N fertilizer,and the optimal rate was 135 kg N ha–1.N uptake increased with an increasing N rate,and the recovery efficiency of applied N (REN) values of the difference subtraction method were 45.23 and 56.98%on average in 2017and 2018,respectively.The RENwas the highest at the N rate of 135 kg ha–1in 2017 and it was insignificantly affected by the N application rate in 2018,while the agronomic efficiency of applied N (AEN) and physiological efficiency of applied N (PEN) decreased significantly when excessive N was applied.N loss through NH3volatilization,leaching and surface runoff was low in the paddy fields in Northeast China.NH3volatilization accounted for 0.81 and 2.99%of the total N application in 2017 and 2018,respectively.On average,the leaching and surface runoff rates were 4.45% and less than 1.05%,respectively,but the apparent denitrification loss was approximately 42.63%.The residual N fertilizer in the soil layer (0–40 cm) was 18.37–31.81 kg N ha–1in 2017,and the residual rate was 19.28–24.50%.Residual15N from fertilizer in the soil increased significantly with increasing N fertilizer,which was mainly concentrated in the 0–10 cm soil layer,accounting for 58.45–83.54% of the total residual N,and decreased with increasing depth.While the ratio of residual N in the 0–10 cm soil layer to that in the 0–40 cm soil layer was decreased with increasing N application.Furthermore,of the residual N,approximately 5.4%was taken up on average in the following season and 50.2%was lost,but 44.4%remained in the soil.Hence,the amount of applied N fertilizer should be reduced appropriately due to the high residual N in paddy fields in Northeast China.The appropriate N fertilizer rate in the northern fields in China was determined to be 105–135 kg N ha–1in order to achieve a balance between rice yield and high N fertilizer uptake. 展开更多
关键词 fate of N fertilizer NH_(3) volatilization leaching surface runoff residual nitrogen yield
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The Clones’Struggle for Happiness under the Doomed Fate in Never Let Me Go
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作者 WANG Xue-juan 《Journal of Literature and Art Studies》 2023年第10期769-774,共6页
Japanese British writer Kazuo Ishiguro is one of the leading writers in contemporary British literature.He has always been committed to creating works with universal significance.Responsibility and destiny are themes ... Japanese British writer Kazuo Ishiguro is one of the leading writers in contemporary British literature.He has always been committed to creating works with universal significance.Responsibility and destiny are themes that run through his works.His novel Never Let Me Go tells a story of a group of clones growing up in the Hailsham,who are given the mission to donate organs at birth.So,there is no doubt that they will inevitably end their lives in the process of donating organs to human beings again and again.The tragic life of clones is determined by the motivation of human to create them. 展开更多
关键词 Kazuo Ishiguro Never Let Me Go clones fate
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猪肠道病毒感染的致病机理与营养调控研究进展 被引量:1
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作者 陈代文 伍爱民 余冰 《动物营养学报》 CAS CSCD 北大核心 2024年第4期2041-2056,共16页
腹泻是养猪业面临的世界性难题,由猪肠道病毒感染导致的仔猪腹泻更是如此。营养与动物健康关系十分密切,营养干预已是防控肠道病毒感染的重要措施。营养干预的理论基础是弄清病毒的致病机制及营养对病毒及其感染与动物康复过程的调节作... 腹泻是养猪业面临的世界性难题,由猪肠道病毒感染导致的仔猪腹泻更是如此。营养与动物健康关系十分密切,营养干预已是防控肠道病毒感染的重要措施。营养干预的理论基础是弄清病毒的致病机制及营养对病毒及其感染与动物康复过程的调节作用。本文在简述猪主要肠道病毒特征基础上,重点围绕免疫、细胞命运和肠道微生物等方面总结了病毒的致病机制和营养调控作用研究进展,旨在为深入认识和研究营养与猪肠道病毒的关系,开发肠道保健和抗病营养技术提供参考。 展开更多
关键词 肠道病毒 免疫 细胞命运 肠道微生物 营养干预
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地理场景与空间建构——地理与麦克白的命运
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作者 白阳明 王莎莎 《美学与艺术评论》 2024年第1期181-193,249,共14页
莎士比亚在《麦克白》中设置许多地理场景,构建出神秘空间和权力空间,命运随着地理场景的不同而变迁,悲剧随着空间的转换而发展,剧中的地理差异反映出麦克白悲惨命运的必然性,呈现地理即命运的观点。研究《麦克白》中的地理场景与空间建... 莎士比亚在《麦克白》中设置许多地理场景,构建出神秘空间和权力空间,命运随着地理场景的不同而变迁,悲剧随着空间的转换而发展,剧中的地理差异反映出麦克白悲惨命运的必然性,呈现地理即命运的观点。研究《麦克白》中的地理场景与空间建构,既提供了一种解读作品的新方法和新视角,又可以更好地理解莎士比亚如何通过地理空间表达时空体验,展现人物命运。 展开更多
关键词 《麦克白》 地理场景 空间建构 命运
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沉默FATE/BJ-HCC-2基因的表达对肝癌细胞迁移及侵袭的影响 被引量:1
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作者 葛丽丽 朴军颜 +2 位作者 杨小昂 尹艳慧 张毓 《郑州大学学报(医学版)》 CAS 北大核心 2015年第6期805-809,共5页
目的:研究FATE/BJ-HCC-2基因表达与肝癌细胞迁移及侵袭的关系。方法:体外合成FATE/BJ-HCC-2基因序列特异性小干扰RNA(siRNA),转染肝癌细胞系克隆株5B4,并设非特异性siRNA转染和空白对照组。采用RT-PCR及Western blot方法检测各组细胞中F... 目的:研究FATE/BJ-HCC-2基因表达与肝癌细胞迁移及侵袭的关系。方法:体外合成FATE/BJ-HCC-2基因序列特异性小干扰RNA(siRNA),转染肝癌细胞系克隆株5B4,并设非特异性siRNA转染和空白对照组。采用RT-PCR及Western blot方法检测各组细胞中FATE/BJ-HCC-2 mRNA和蛋白的表达;通过Transwell小室模型检测各组细胞体外迁移及侵袭的能力;激光共聚焦显微镜下观察5B4及空质粒转染的对照细胞(Mock)的骨架结构。结果:各组细胞中FATE/BJ-HCC-2 mRNA和蛋白表达差异有统计学意义(F=15.321,P=0.020),特异性siRNA转染组细胞低于其他2组(P<0.05)。抑制FATE/BJ-HCC-2基因表达后,细胞体外迁移及侵袭的能力降低(F=6.171和10.109,P<0.05)。5B4细胞形态拉长,蝌蚪状,呈现迁移、游走的状态;微丝丰富,形态规则,平行贯穿于细胞全长,细胞膜周围有较多丝状伪足伸出;微管减少,分布不规则。结论:FATE/BJ-HCC-2基因表达促进肝癌细胞的迁移及侵袭。 展开更多
关键词 fate/BJ-HCC-2 RNA干扰 肝癌 转移
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包气带中手性抗生素的环境行为研究进展
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作者 秦晓鹏 刘菲 +1 位作者 王广才 翁莉萍 《水文地质工程地质》 CAS CSCD 北大核心 2024年第2期23-34,共12页
目前,手性抗生素在包气带中的检测、分布、迁移转化等方面缺乏系统总结和全面综述。文章指出手性抗生素不同异构体的物理化学性质存在差异,例如左旋吉米沙星的溶解度、辛醇-水分配系数分别是右旋吉米沙星的301倍、9.8倍,会影响其在环境... 目前,手性抗生素在包气带中的检测、分布、迁移转化等方面缺乏系统总结和全面综述。文章指出手性抗生素不同异构体的物理化学性质存在差异,例如左旋吉米沙星的溶解度、辛醇-水分配系数分别是右旋吉米沙星的301倍、9.8倍,会影响其在环境中的迁移转化。高效液相色谱-手性色谱柱法和手性配体交换色谱法是目前最常用的分析手性抗生素的方法。梳理了国内外土壤、水体和农产品中手性抗生素的检出情况,其中最常见的是氟甲喹、洛美沙星、氧氟沙星等。手性抗生素在矿物和微塑料上的吸附速率和分配系数均存在差异,天然有机物的存在导致差异更大,但是不同种类手性抗生素之间并没有规律。手性抗生素会与地下水中的常见阳离子发生络合作用,络合物的稳定常数不同,例如镁离子-左氧氟沙星络合物的稳定常数是镁离子-氧氟沙星络合物的22.9倍。在生物降解过程中,不同手性抗生素的可降解性、降解速率不同,另外,抗生素异构体之间还会发生相互转化。文章系统阐述了手性抗生素在包气带中的分布情况和迁移转化行为,可供地下水系统中手性抗生素方面的研究参考。研究认为对于包气带中手性抗生素的环境行为,亟需开展以下研究:(1)手性抗生素的拆分、检测、毒理学和标准建设;(2)多种手性抗生素的调查、迁移转化;(3)手性抗生素的多界面环境过程。 展开更多
关键词 抗生素 手性 异构体 土壤 环境行为 氧氟沙星
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改良剂对土壤熏蒸剂环境行为影响研究进展
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作者 张毅 陈新华 +5 位作者 纪宇桐 曹坳程 方文生 颜冬冬 李园 王秋霞 《现代农药》 CAS 2024年第1期23-31,50,共10页
土壤熏蒸剂的环境行为直接关系到其应用效果及安全性,土壤改良剂的施用会直接影响到熏蒸剂的环境行为。系统综述了目前国内外无机、有机肥类土壤改良剂、生物炭土壤改良剂等添加后对不同熏蒸剂降解、迁移、散发、吸附、淋溶等环境行为... 土壤熏蒸剂的环境行为直接关系到其应用效果及安全性,土壤改良剂的施用会直接影响到熏蒸剂的环境行为。系统综述了目前国内外无机、有机肥类土壤改良剂、生物炭土壤改良剂等添加后对不同熏蒸剂降解、迁移、散发、吸附、淋溶等环境行为的影响。结果表明:土壤改良剂对熏蒸剂环境行为的影响因改良剂种类、剂量、施用方式而异,可以为保障熏蒸剂应用效果、开发特定土壤改良剂、促进农业健康可持续发展提供参考。 展开更多
关键词 土壤改良剂 土壤熏蒸剂 环境行为 应用效果
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Effect of Transplanting Density on Rice Yield,Nitrogen Uptake and ^(15)N-fertilizer Fate 被引量:5
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作者 樊红柱 张鸿 +2 位作者 冯文强 张冀 王昌桃 《Agricultural Science & Technology》 CAS 2012年第5期1037-1039,1054,共4页
[Objective] The aim of this study was investigated the rice yield, nitrogen uptake and ^15-fertilizer fate at different transplanting density to provide scientific ba- sis for improving the yield of rice and applying ... [Objective] The aim of this study was investigated the rice yield, nitrogen uptake and ^15-fertilizer fate at different transplanting density to provide scientific ba- sis for improving the yield of rice and applying reasonably fertilizer. [Method] A field experiment was carried out to study the effect of different transplanting density on rice yield, nitrogen (N) absorption, sources of N uptake by rice and the N balance in the plant-soil systems by using ^15-labelled urea. [Result] There were no significant differences in rice yields and total N uptakes by rice between treatments 30 cm × 30 cm and 40 cm × 40 cm, but the yield of rice and total N absorption in the two treatments were remarkably higher than those in 50 cm × 50 cm treatment. The amounts of total N uptake by rice were in the range of 112.3-162.7 kg/hm2 in the three transplanting densities. The result showed that about 1/3 of the total N uptake by rice was supplied by application fertilizer and the other 2/3 was obtained from the soil N pool. The ^15N-labelled urea absorbed by rice, residual in soil and lost accounted for 16.3%-26.1%, 17.0%-20.9% and 53.0%-66.7% of the total fertilizer, respectively. A great deal of ^15N-labelled urea was lost during the rice growing season. [Conclusion] Considering the rice yield and environmental protection, the transplanting density of 30 cm×30 cm was recommended in the hilly area of Sichuan basin in the southwest China. 展开更多
关键词 Rice yield Nitrogen uptake and balance ^15N-labeled urea ^15N fate Transplanting density
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缬菌胺和代森锰锌的残留特征及膳食暴露风险评估
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作者 许晨 赵沛莹 +6 位作者 刘凤娇 王曦 康珊珊 袁龙飞 赵莉蔺 李薇 陈增龙 《植物保护》 CAS CSCD 北大核心 2024年第2期119-128,共10页
本文建立了缬菌胺、代森锰锌及其代谢物乙撑硫脲(ethylenethiourea,ETU)在葡萄和黄瓜中的痕量分析方法,基于储藏稳定性研究阐明了其田间残留特征,并结合我国膳食结构评估了膳食暴露风险。样本经乙腈提取,衍生化后盐析离心,分散固相萃取(... 本文建立了缬菌胺、代森锰锌及其代谢物乙撑硫脲(ethylenethiourea,ETU)在葡萄和黄瓜中的痕量分析方法,基于储藏稳定性研究阐明了其田间残留特征,并结合我国膳食结构评估了膳食暴露风险。样本经乙腈提取,衍生化后盐析离心,分散固相萃取(d-SPE)净化,超高效液相色谱质谱联用仪(UPLC-MS/MS)检测。缬菌胺、代森锰锌和ETU在葡萄和黄瓜基质中的平均回收率分别为84%~103%、86%~106%和83%~104%,相对标准偏差分别为1.1%~5.7%、0.8%~11.4%、4.4%~11.5%;-20℃避光条件下能在黄瓜和葡萄基质中分别稳定储藏720 d和758 d。缬菌胺和代森锰锌在黄瓜中的半衰期(1.7~2.4 d和1.4~2.7 d)均比在葡萄(6.5~30.1 d和8.6~12.8 d)中的短,而在葡萄中的最终残留浓度(<0.01~0.69 mg/kg)均比黄瓜(<0.01~0.16 mg/kg)中的高。两种果蔬中代森锰锌对儿童群体和一般人群急性膳食风险(%ARfD)分别为0.70%~3.68%和0.48%~2.53%,远低于100%;而代森锰锌和缬菌胺的联合慢性膳食风险为201.3%~831.7%,其中代森锰锌占比99.9%。可见,缬菌胺不会对我国消费者产生不可接受的膳食风险,但需警惕代森锰锌潜在高暴露风险,持续关注其在食物链中的生物累积风险,同步优化膳食结构,为其科学合理使用和健康风险规避提供理论依据。 展开更多
关键词 缬菌胺 代森锰锌 环境行为 风险评估 储藏稳定性
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番茄嫁接和施氮对氮肥去向和氮平衡的影响
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作者 孙昭安 张译文 +4 位作者 江丽华 李昭君 郭鑫 曹慧 孟凡乔 《中国农业科学》 CAS CSCD 北大核心 2024年第4期755-764,共10页
【目的】定量番茄植株地上部带走的土壤氮量以及土壤残留的肥料氮量,评估嫁接和施氮对氮肥去向、土壤氮平衡以及土壤净残留肥料氮的影响。【方法】通过15N尿素示踪结合盆栽试验,试验番茄品种‘齐达利’和‘017’,包括嫁接和不嫁接以及... 【目的】定量番茄植株地上部带走的土壤氮量以及土壤残留的肥料氮量,评估嫁接和施氮对氮肥去向、土壤氮平衡以及土壤净残留肥料氮的影响。【方法】通过15N尿素示踪结合盆栽试验,试验番茄品种‘齐达利’和‘017’,包括嫁接和不嫁接以及施氮和不施氮处理。借助15N标记技术区分植株和土壤中源于肥料氮和土壤氮的贡献,进而追踪肥料氮去向;计算土壤氮吸收的加氮交互效应(即施氮与不施氮植株对土壤氮吸收的差值),最终评估土壤氮的平衡。【结果】番茄植株干重和氮吸收量对施氮的响应取决于接穗品种和嫁接处理。肥料氮对整个植株氮吸收贡献率为35.9%—38.8%,对地上部氮吸收的贡献(35.9%—39.9%)高于根系(31.6%—36.2%)。土壤氮吸收的加氮交互效应在大多数情况下呈现正值,嫁接对加氮交互效应无显著影响。各处理肥料氮分配到植株地上部、土壤和损失的平均比值为4.0﹕2.6﹕3.4,作物-土壤系统对氮肥的总回收率(地上部吸收+土壤残留)为70%。在施氮量250 kg·hm^(-2)水平,各处理的土壤残留肥料氮无法弥补植株地上部带走的土壤本身氮,从长期来看,这可能导致土壤本身氮肥力的消耗。【结论】如果选择增加氮肥投入来弥补土壤本身氮的消耗,可能导致氮肥损失的风险。本研究中,与番茄‘齐达利’自根苗、‘017’自根苗和嫁接苗相比,‘齐达利’接穗与南瓜砧木组合增加了根际土壤对肥料氮的固持,降低了肥料氮的损失。因此,合适砧穗组合可能是保持番茄土壤氮肥力的有效园艺措施。 展开更多
关键词 番茄 氮肥利用率 加氮交互效应 化肥氮去向 15N标记
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主观社会阶层正向预测居民生育意愿 被引量:4
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作者 万丰华 陈思静 《人口与发展》 CSSCI 北大核心 2024年第2期26-38,共13页
生育意愿能够有效地预测实际生育水平,它受到社会阶层的影响。基于CGSS2010至2017年数据的分析表明:(1)主观社会阶层正向预测生育意愿,这一结果在工具变量内生性检验以及多个稳健性检验中相当稳健。(2)性别平等意识在主观社会阶层和生... 生育意愿能够有效地预测实际生育水平,它受到社会阶层的影响。基于CGSS2010至2017年数据的分析表明:(1)主观社会阶层正向预测生育意愿,这一结果在工具变量内生性检验以及多个稳健性检验中相当稳健。(2)性别平等意识在主观社会阶层和生育意愿之间起到部分中介的作用。(3)异质性分析表明,主观社会阶层对居民生育意愿的影响存在性别和受教育程度异质性。(4)共同命运模型分析表明,家庭层面的主观社会阶层正向预测家庭层面的生育意愿。上述发现有助于完善和丰富国内外生育意愿研究领域的相关理论,并为相关生育政策制定提供科学的理论支持和决策参考。 展开更多
关键词 社会阶层 生育意愿 性别平等意识 共同命运模型
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Fate of ^(15)N Labeled Nitrate and Ammonium Salts Added to an Alpine Meadow in the Qinghai-Xizang Plateau, China 被引量:5
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作者 徐兴良 欧阳华 +1 位作者 裴志永 周才平 《Acta Botanica Sinica》 CSCD 2003年第3期276-281,共6页
To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was... To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was determined in an alpine meadow for two months. Two weeks after 15 N application, total recovery of 15 N from NO - 3_ 15 N was 73.5% while it was 78% from NH + 4_ 15 N. More 15 N was recovered in plants than in soil organic matter or in microbial biomass, irrespective of forms of N added. After one month, 70.6% of added NO - 3_ 15 N and 57.4% of NH + 4_ 15 N were recovered in soils and plants. 15 N recovered in soil organic matter decreased greatly while that recovered in plants varied little, irrespective of the form N. Compared with the results of two weeks after 15 N application, more NO - 3_ 15 N than NH + 4_ 15 N was recovered in microbial biomass. Total recovery was 58.4% (six weeks) and 67% (eight weeks) from NO - 3_ 15 N, and 43.1% and 49% from NH + 4_ 15 N, respectively. Both plants and soil microorganism recovered more NO - 3_ 15 N than NH + 4_ 15 N. But plants recovered more 15 N than soil microorganisms. During the whole experiment plants retained more NO - 3_N and 15 N than soil microorganisms while 15 N recovered in inorganic N pool did not exceed 1% due to lower amount of inorganic N. This indicates that plants play more important roles in the retention of deposited N although microbial biomass can be an important sink for deposited N in early days after N application. 展开更多
关键词 alpine meadow soil microorganisms retention of deposited N percentage of 15 N recovery fate of NO - 3_ 15 N and NH + 4_ 15 N
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污水处理厂化学品环境归趋模型研究现状及展望 被引量:1
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作者 司鸿德 张少轩 +3 位作者 张冰 范科文 王通 张嘉之 《环境化学》 CAS CSCD 北大核心 2024年第10期3388-3405,共18页
污水处理厂化学品环境归趋模型是化学品末端管控的重要工具.当前针对污水处理厂中化学品迁移、转化和分布预测的模型开发及应用逐渐增加,但相关模型种类较多、适用性各具特点,尚缺乏污水处理厂化学品环境归趋模型的综合比较和应用清单报... 污水处理厂化学品环境归趋模型是化学品末端管控的重要工具.当前针对污水处理厂中化学品迁移、转化和分布预测的模型开发及应用逐渐增加,但相关模型种类较多、适用性各具特点,尚缺乏污水处理厂化学品环境归趋模型的综合比较和应用清单报道.本文汇总了目前已用于污水处理厂内化学品环境归趋模拟的模型与化学品适用清单,根据模型建模机理,将其分为三类:基于逸度原理(STP)、基于质量浓度(SimpleTreat、WW-TREAT、WATER9、TOXCHEM和WEST等)以及基于活度原理(Activity SimpleTreat)的污水处理厂化学品环境归趋模型.本文系统性介绍了相关模型的基本结构、原理和不同场景下化学品归趋研究的应用情况,概述其在表达形式、输入参数、输出结果以及适用案例等方面的局限性和优点,结合数百个模拟/监测数据集进一步验证各类模型的准确性,并探讨其不确定性重要来源.文章为目前污水处理厂化学品环境归趋模拟研究提供了更清晰的现状分析,为新污染物末端治理工具的选择提供了参考依据,并总结了该领域的发展趋势和前景. 展开更多
关键词 化学品 环境归趋 污水处理 模型.
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