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Border Sensitive Knowledge Distillation for Rice Panicle Detection in UAV Images 被引量:1
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作者 Anitha Ramachandran Sendhil Kumar K.S. 《Computers, Materials & Continua》 SCIE EI 2024年第10期827-842,共16页
Research on panicle detection is one of the most important aspects of paddy phenotypic analysis.A phenotyping method that uses unmanned aerial vehicles can be an excellent alternative to field-based methods.Neverthele... Research on panicle detection is one of the most important aspects of paddy phenotypic analysis.A phenotyping method that uses unmanned aerial vehicles can be an excellent alternative to field-based methods.Nevertheless,it entails many other challenges,including different illuminations,panicle sizes,shape distortions,partial occlusions,and complex backgrounds.Object detection algorithms are directly affected by these factors.This work proposes a model for detecting panicles called Border Sensitive Knowledge Distillation(BSKD).It is designed to prioritize the preservation of knowledge in border areas through the use of feature distillation.Our feature-based knowledge distillation method allows us to compress the model without sacrificing its effectiveness.An imitation mask is used to distinguish panicle-related foreground features from irrelevant background features.A significant improvement in Unmanned Aerial Vehicle(UAV)images is achieved when students imitate the teacher’s features.On the UAV rice imagery dataset,the proposed BSKD model shows superior performance with 76.3%mAP,88.3%precision,90.1%recall and 92.6%F1 score. 展开更多
关键词 Rice panicle detection UAV border sensitive method deep learning knowledge distillation
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Specialization or Diversification:Which is More Conducive to Foreign Trade Resilience?Evidence from China-Russia Border Regions in Northeast China
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作者 LI Yuxin ZHANG Pingyu +1 位作者 YANG Qifeng CHU Nanchen 《Chinese Geographical Science》 SCIE CSCD 2024年第6期1144-1157,共14页
Under the background of complex international situation,how to build the special geo-economic space of China-Russia bor-der lies in strengthening their foreign trade resilience against external shocks.Based on empiric... Under the background of complex international situation,how to build the special geo-economic space of China-Russia bor-der lies in strengthening their foreign trade resilience against external shocks.Based on empirical evidence from ten prefecture-level China-Russia border regions in Northeast China,this paper analyzed the spatiotemporal evolution of foreign trade resilience under different shocks.Furthermore,through the Panel Regression model,the mechanism of the industrial structure on the foreign trade resilience in contraction period and expansion period was discussed.The results showed that:1)from 2004 to 2021,foreign trade in China-Russia border regions experienced five phases.The overall foreign trade resilience was higher than expected,showing a rising volatility trend,but there was significant spatial heterogeneity in the ability of cities to cope with shocks.2)Highly specialized clusters were mainly concentrated in Yichun,Heihe and Da Hinggan Ling Prefecture,while Mudanjiang and Yanbian performed better in related and unrelated diversification.3)In different stages of economic system evolution,the response mode,degree and result of border foreign trade resilience to regional industrial structure showed obvious stage characteristics.During the contraction period,related diversification was more conducive to improving the resistance through risk spillovers.During the expansion period,specialization played a more significant role in improving regional resilience through self-reinforcing effect.These results are beneficial for expanding the resilience theory,ensuring border economic security and optimizing border industrial investment layout. 展开更多
关键词 foreign trade resilience industrial structure SPECIALIZATION Panel Regression model China-Russia border regions North-east China
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Application and Adaptability of Ornamental Grasses in Road Flower Borders in Hefei, Anhui Province
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作者 ZHAO Haishuang ZHAO Zhiyan 《Journal of Landscape Research》 2024年第4期70-72,79,共4页
In-depth research was conducted on the types,seasonal patterns,spatial levels,overwintering,summering,drought resistance,and disease and pest resistance of ornamental grasses in the road flower borders of Hefei,Anhui ... In-depth research was conducted on the types,seasonal patterns,spatial levels,overwintering,summering,drought resistance,and disease and pest resistance of ornamental grasses in the road flower borders of Hefei,Anhui Province.Through field investigations,a total of 36 ornamental grasses were identified,with Liliaceae having the most species and the Lamiaceae the least.The results show that there are more warm season ornamental grasses,of 23 species;Acorus gramineus and Melinis minutiflora have poor overwintering ability;Arrhenatherum elatius,Festuca glauca,and Stipa tenuissima have poor summer tolerance;most ornamental grasses have strong drought resistance and resistance to pests and diseases.The comprehensive investigation shows that ornamental grasses have good application prospects and adaptability in the road flower borders in Hefei city. 展开更多
关键词 Ornamental grass Hefei Road flower border APPLICATION ADAPTABILITY
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AHP-based Landscape Value Evaluation of Perennial Flower Border Application in Hefei City
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作者 ZHENG Xinhong ZHAO Zhiyan LI Jie 《Journal of Landscape Research》 2024年第3期8-10,14,共4页
An analytic hierarchy process(AHP)was employed to establish a landscape value evaluation model for 20 common species of perennial flowers in the flower border of Hefei City.With the overarching objective of determinin... An analytic hierarchy process(AHP)was employed to establish a landscape value evaluation model for 20 common species of perennial flowers in the flower border of Hefei City.With the overarching objective of determining the application value of the flower border,10 evaluation factors were identified and subsequently classified into 3 distinct grades.Grade I(L>2.5)was defined as perennial flower resources with the highest development and utilization value,including only one species of Salvia farinacea.Grade II(2.0≤L≤2.5)was defined as perennial flower varieties suitable for most areas,encompassing 9 species of plants,such asTaraxacummongolicum.Grade III(L<2.0)was defined as perennial flower varieties with low application value,encompassing 10 species of plants,such asRuellia brittoniana,but lacking the value of further popularization and application.Consequently,the proportion of their application in the flower border should be reduced.The evaluation results can serve as a theoretical foundation for the implementation of perennial flowers in urban flower borders. 展开更多
关键词 AHP Perennial flower Landscape value Flower border
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Application of Flower Borders in Hefei City
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作者 MENG Yuyang ZHAO Zhiyan +3 位作者 ANG Shengchao MENG Yi WEN Shiyang OU Xueni 《Journal of Landscape Research》 2024年第4期27-30,共4页
The application value of 70 kinds of flowers in Hefei City was evaluated by analytic hierarchy process(AHP).From the three aspects of adaptability,ornamental value and economic traits,12 indicators were summarized to ... The application value of 70 kinds of flowers in Hefei City was evaluated by analytic hierarchy process(AHP).From the three aspects of adaptability,ornamental value and economic traits,12 indicators were summarized to establish a comprehensive evaluation system.The results show that the application of grade-I plants(J≥3.6642)in flower borders is the most suitable,and they include 19 species of plants such as Osmanthus fragrans var.thunbergii,accounting for 27.14%.The application of grade-II plants(3.2319≤J≤3.6641)in flower borders is suitable,and 36 species of plants such as Jacobaea maritima are included,with the proportion of 51.42%.The application of grade-III plants(2.7935≤J≤3.2318)in flower borders is relatively suitable,and they contain 8 species of plants such as Acer palmatum’Atropurpureum’(Van Houtte)Schwerim,accounting for 11.42%.Grade-IV plants(J≤2.7934)can be applied in flower borders under special circumstances,and include 6 species of plants such as Muehlenbeckia complexa Meisn.,accounting for 8.57%.The results can provide reference for the selection of flower border plants in Hefei.The locations and types of 40 flower borders were summarized to provide a basis for the development direction and future planning of flower borders in Hefei. 展开更多
关键词 Analytic hierarchy process(AHP) Flower border Application value Comprehensive evaluation
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Cross-border E-commerce Accelerates Diversely Abroad
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作者 Guo Yan 《China's Foreign Trade》 2024年第1期14-15,共2页
“Strength”and“vitality”are the comments that people in the industry have used to describe China’s cross-border e-commerce in 2023,which has been proven by the latest statistics.According to the General Administra... “Strength”and“vitality”are the comments that people in the industry have used to describe China’s cross-border e-commerce in 2023,which has been proven by the latest statistics.According to the General Administration of Customs,in 2023,the total volume of imports and exports was RMB 2.38 trillion,up by 15.6%.The volume of exports was RMB 1.83 billion,up by 19.6%,and the volume of imports was RMB 548.3 billion,up by 3.9%. 展开更多
关键词 IMPORTS border COMMERCE
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Enhancement of Competitiveness of Border Trade Entrepreneurs: Case Study of Su-Ngai Kolok Checkpoint, Narathiwat Province
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作者 Sumalee Grodgangunt Roihan Saaree +2 位作者 Chonlakan Satabodee Rungsiri Padungrat Mathurose Tongintharach 《Management Studies》 2024年第4期225-244,共20页
This research aimed to analyze the enhancement of competitiveness among fruit and vegetable export entrepreneurs,with the case study of the Su-ngai Kolok checkpoint in Narathiwat Province.This research focused on thre... This research aimed to analyze the enhancement of competitiveness among fruit and vegetable export entrepreneurs,with the case study of the Su-ngai Kolok checkpoint in Narathiwat Province.This research focused on three objectives:(1)examining how competitiveness is enhanced through government support and the development of border trade zones,(2)studying the supply chain dynamics,including strategic factors and opportunities in agricultural product management,and(3)developing a model for border trade to strengthen exporters’capabilities.The research employed qualitative methods,with data collected from 25 informants through interviews and employed descriptive methods.The research results revealed that:(1)government agencies play a crucial role in improving competitiveness by developing border economic zones and trade policies;additionally,(2)the research highlighted the importance of strategic partnerships,network building,and efficient logistics along the value chain;(3)the proposed Border Trade Model includes elements for instance government policy,partnerships,entrepreneurial potential,and transportation channels,aiming to enhance the overall efficiency and effectiveness of vegetable and fruit exporters in the region. 展开更多
关键词 ENHANCEMENT COMPETITIVENESS border trade entrepreneurs
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Research on the Employment View of Acupuncture and Tuina Undergraduates in Minority Border Areas from Students’ Perspective
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作者 Rongshuang Yang Kai Yuan +5 位作者 Minjie Yin Ruilu Liu Zhihao Zhang Lijuan Wang Yanfang Yang Xinghe Zhang 《Journal of Contemporary Educational Research》 2024年第8期265-275,共11页
With the popularization of higher education in China,the employment situation of college students is more complex and severe.This paper adopts the questionnaire method to explore the employment view of acupuncture and... With the popularization of higher education in China,the employment situation of college students is more complex and severe.This paper adopts the questionnaire method to explore the employment view of acupuncture and tuina undergraduates of Yunnan University of Traditional Chinese Medicine.The employment concept of acupuncture and tuina undergraduates in the minority border areas has changed greatly.After graduation,97.95%of students choose to work in fields related to medicine and acupuncture,prefer positions close to home,and are attracted to high-salary companies,among other factors.Therefore,enhancing the competitive advantages of medical students by guiding their career planning,providing employment selection advice,fostering innovation and entrepreneurship,improving basic skills,and offering graduate entrance examination guidance is crucial for broadening their employment opportunities. 展开更多
关键词 Undergraduate EMPLOYMENT Minority border areas Acupuncture and tuina
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Developmental Regulation and Biological Functions of Root Border Cells in Higher Plants 被引量:12
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作者 潘建伟 朱睦元 +1 位作者 彭华正 王利琳 《Acta Botanica Sinica》 CSCD 2002年第1期1-8,共8页
Root border cells, previously referred to as sloughed root cap cells, is a special cell population which separates in large numbers from the periphery of the root cap and accumulates in the root tip. Recent evidence r... Root border cells, previously referred to as sloughed root cap cells, is a special cell population which separates in large numbers from the periphery of the root cap and accumulates in the root tip. Recent evidence reveals that border cells, whose development is regulated by endogenous and exogenous signals, are biologically viable in the majority of higher plant species. As soon as border cells detach from root cap periphery, their metabolic activity dramatically increases in accordance with a differential gene expression from that in root cap cells. Recently, PsUGT1 and RCPME1, relevant to the early and late stage of border cell development, respectively, have been cloned and functionally identified. Border cells can synthesize specially and export a diverse array of chemicals including anthocyanins, antibiotics, special enzymes and other substances, that either inhibit or promote the growth of other entities in rhizosphere such as bacteria, fungi, viruses, and nematodes, and also antagonize some toxic chemicals around the root tip in soil such as aluminum toxicity. Therefore, there are multiple biological roles played by border cells during plant growth and development. 展开更多
关键词 border cells DEVELOPMENT FUNCTION PLANT STRESS
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美国B&N与Borders书店的POP广告 被引量:1
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作者 方卿 徐丽芳 《出版发行研究》 CSSCI 北大核心 2004年第9期58-61,共4页
POP广告是卖场促销的重要手段之一。美国的大书店POP广告有几种,是如何做的?两位在美国做访问学者的作者实地考查后在文中给您详实、深入、具体的介绍。
关键词 美国 B&N 连锁书店 borders书店 POP广告 卖场广告 图书打折
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Application of Flower Border at Senlinyicheng Residential District in Qinhuangdao City
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作者 巩如英 王颖 +2 位作者 杜洁 徐迎碧 温瑀 《Journal of Landscape Research》 2012年第3期49-50,54,共3页
Application of flower border in Senlinyicheng Residential District(or Leisure Forest City) was investigated and analyzed.The results showed that(a) there are 18 flower border species of 11 families,and 16 of them are ... Application of flower border in Senlinyicheng Residential District(or Leisure Forest City) was investigated and analyzed.The results showed that(a) there are 18 flower border species of 11 families,and 16 of them are perennial and bulbous flower species,accounting for 88.9% of the total;(b) flowering season lasts from April to the late October;(c) flower borders are colorful and dominated by large lumps of colors;(d) there are 3 major types:forest edge flower border,roadside flower border and waterfront flower border.Meanwhile,problems of flower border in the study district were summarized as poor sustainability,poor landscape effects in early spring,autumn and winter,monotonous landscapes and ineffective management.Correspondingly,countermeasures were given as enhancing the sustainability of flower border landscapes,improving landscape effects in early spring,autumn and winter,applying more species with better cold and stress resistance. 展开更多
关键词 Qinhuangdao Senlinyicheng RESIDENTIAL DISTRICT FLOWER border
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Establishment and Application of Flower Border Plant Database for Beijing
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作者 夏冰 何婷婷 董丽 《Journal of Landscape Research》 2010年第10期30-33,共4页
Through field investigation and phenological observation, Microsoft Access database management system is used to establish a relatively comprehensive database of flower border plant materials for Beijing which can pro... Through field investigation and phenological observation, Microsoft Access database management system is used to establish a relatively comprehensive database of flower border plant materials for Beijing which can provide multi-perspective retrieval channels, so as to effectively select materials for designing and building flower borders. 展开更多
关键词 MICROSOFT Access FLOWER border PLANT materials DATABASE
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CONCEPTION OF ESTABLISHING THE SINO-RUSSIAN BORDER FREE ECONOMIC REGION
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作者 于国政 王荣芬 《Chinese Geographical Science》 SCIE CSCD 1999年第3期44-50,共7页
So called free economic region is a special region without jurisdiction of customs, delimited by one country. There are mainly four types of free economic region, that is, commercial type of free economic region —fre... So called free economic region is a special region without jurisdiction of customs, delimited by one country. There are mainly four types of free economic region, that is, commercial type of free economic region —free port, industrial type of free economic region — export processing area, integrated commercial and trade type of free economic region — free trade zone, and scientific and technological type of free economic region — scientific industrial park. With the development of free economic region of different countries, besides free economic region within one country, there appear transnational border free economic region established by two or multiple countries. Analysing favorable factors and unfavorable factors to establish the free economic region for China and Russia, for example, China and Russia have land boundary line of 4282.7 km; China and Russia may strengthen overall cooperation in politics, military, economy, science and technology, culture, etc. making full use of geographical factors of the two countries, borders; there is a strong complementarity in resources, labour force etc. for China and Russia; strengthening the Sino Russian economic trade cooperation is needed, the authors proposed a conception and selected four comparative ideal locations for establishing the Sino Russian border free economic region: Manzhouli Zabaikalye Free Economic Region, Heihe Blagoveshchensk Free Economic Region, Suifenhe Pogranichnyy Free Economic Region, Hunchun Hasan Free Economic Region. Finally the principles and patterns for establishing free economic region are discussed. 展开更多
关键词 free ECONOMIC region the SINO RUSSIAN borders border TRADE
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Paired Border Towns or TwinCities from Finland and China
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作者 Riitta Kosonen Xu Feng Erja Kettunen 《Chinese Journal of Population,Resources and Environment》 北大核心 2008年第1期3-13,共11页
This paper discusses cross-border cooperation at the level of urban socio-economic systems. Worldwide, cross-border urban cooperation has in several cases produced socio-economic and political coherence supported by v... This paper discusses cross-border cooperation at the level of urban socio-economic systems. Worldwide, cross-border urban cooperation has in several cases produced socio-economic and political coherence supported by various joint programs and efforts. However, the degree of coherence varies and seldom cre-ates socio-economically and politically tightly integrated "Twin-Cities" where the state border becomes highly transparent or ob-scure. Focusing on Finlan d and China, our aim is to identify whether the selected border towns represent coherent TwinCities or a more loose type of "paired border towns". The study uses an empirical examination of three Finnish towns (Helsinki, Tornio, Imatra) and their neighboring towns in Estonia, Sweden, and Rus-sia as a benchmark. Then, a comparative study is made regarding three Chinese cross-border cities facing Russia, Vietnam and Ka-zakhstan. We highlight the differences in cross-border integration from the viewpoint of shared public sector programs, cross-border enterprise relocation and networking, and integrated social sector in terms of labor market, education and shopping area. 展开更多
关键词 paired border towns ideal TwinCity model cross-border cooperation and networking FINLAND China
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Challenges Facing Zimbabwean Cross Border Traders Trading in South Africa: A Review of Literature
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作者 Norman Chiliya Reginald Masocha Stanislous Zindiye 《Chinese Business Review》 2012年第6期564-570,共7页
Cross border traders make a major contribution to the growth of economies in Southern Africa. Cross border trade is a source of livelihood for many poor people, especially women. However, few studies examined challeng... Cross border traders make a major contribution to the growth of economies in Southern Africa. Cross border trade is a source of livelihood for many poor people, especially women. However, few studies examined challenges facing cross border traders and future business prospects.The aim of this paper is to examine the challenges that face Zimbabwean cross border traders in South Africa. The paper goes further to review existing literature as well as empirical studies in order to identify the major challenges that face Zimbabwean cross border traders. Among the challenges noted are crime, harassment due to xenophobia, traders are often stigmatized as "prostitutes" or "smugglers", accommodation problems, extortion and bribery by the South African Police and municipal police officials, delays at the border post during peak periods and banks that close early and also do not operate on Sundays. The Zimbabwean Cross Border Traders Association should build office in Musina and Johannesburg so that members can easily consult with the association in times of problems and also help with marketing information like distribution of brochures showcasing Zimbabwean products sold by cross border traders and also organize fairs where Zimbabwean traders can display their products. Furthermore cases of harassment by police officials should be investigated and dealt with. Banks that do have branches at the border posts are also urged to provide 24 hour service to cross border traders. 展开更多
关键词 cross border traders CHALLENGES regional trade border exchange GOODS
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Geographical Factor as a Basis for Research of State BordersmAn Example of Georgia
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作者 Dali A. Nikolaishvili Revaz Sh. Tolordava 《Journal of Earth Science and Engineering》 2013年第10期701-713,共13页
The work deals with analysis of geographical factor as one of the main factor determining the historical change of a border on the example of Georgia. The research was conducted in two main directions: the evaluation... The work deals with analysis of geographical factor as one of the main factor determining the historical change of a border on the example of Georgia. The research was conducted in two main directions: the evaluation of historical transformations of state borders of Georgia throughout of XIX-XX centuries and identification the leading geographical factors. Special emphasis has been made on geographical and cartometric analysis of modern state border of Georgia. In order to identify the historical transformations of state border that have used different methods as well as GIS-technologies, the research is based on the historical, cartographical and statistical data. On the base of a lot of cartographic sources, it is concluded that the borderline in modem topographic maps is often plotted by ignoring the international practice related to plotting the state borders across the physical-geographical objects. This is why the geographical factor seems important in the historical transformations of the state border creating similarly a negative perspective in the future. The main results of research are: (1) classification of geographical factors causing the transformations of the state borders; (2) Evaluation of sensitivity of state border; and (3) creation of DB of the state border of Georgia, allowing continuing the studies in the future. 展开更多
关键词 State border types of Sate border cartometric-geographical analysis geographical factor Georgia.
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Regulating Crossing Border E-commerce by SC
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作者 Hao Song 《Sociology Study》 2018年第5期251-255,共5页
Crossing border e‐commerce develops rapidly because of e‐commerce development.There are three typical modes of crossing border e‐commerce,and they are B2B(business to business),B2C(business to customer),and C2C(cus... Crossing border e‐commerce develops rapidly because of e‐commerce development.There are three typical modes of crossing border e‐commerce,and they are B2B(business to business),B2C(business to customer),and C2C(customer to customer).With the development of social network,a new mode called C2C cross‐border e‐commerce by SC(social commerce)is occurring.This new kind of e‐commerce has several advantages,like high trust between seller and customer and personalized consumption for customers.But there are still some problems of C2C cross‐border e‐commerce by SC,which are tax evasion and no rule to regulate.To solve these problems,several measures should be taken into account.In the area of Customs Law,it should refine the standard of luggage and post package taxation.The Custom should strengthen supervision for international post package.To deal with the problem that there is no law to regulate C2C cross‐border e‐commerce by SC,Contract Law is suitable before the E‐commerce Law enacts. 展开更多
关键词 CROSSING border E-COMMERCE C2C CROSS-border E-COMMERCE by SC custom LAW customer protection act contract LAW
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Developmental Characteristics and Cinnamic Acid Resistance of Root Border Cells in Cucumber and Figleaf Gourd Seedlings 被引量:12
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作者 QIAO Yong-xu ZHANG Yong-ping +2 位作者 ZHANG Hong-xin TIAN Yong-qiang GAO Li-hong 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第11期2065-2073,共9页
Root border cells (RBCs) originate from the root tip epidermis and surround the root apices. In this study, we evaluated the developmental characteristics and the roles of RBCs in protection of root apices of cucumb... Root border cells (RBCs) originate from the root tip epidermis and surround the root apices. In this study, we evaluated the developmental characteristics and the roles of RBCs in protection of root apices of cucumber and ifgleaf gourd seedlings from CA toxicity. The formation of RBCs and the emergence of the root tip occurred almost simultaneously in root apices of cucumber and ifgleaf gourd seedlings. CA ranging from 0 to 0.25 mol L-1 inhibited root elongation and decreased root cell viability in the root tip, moreover the inhibitory effects of CA were more signiifcant in the CA-sensitive cucumber than in the CA-tolerant ifgleaf gourd. Removal of RBCs from root tips led to more severe CA induced inhibition of root elongation and decline in root cell viability. Increasing CA levels and treatment time decreased the relative viability of attached and detached RBCs. CA also induced a thicker mucilage layer surrounding attached RBCs of both species. Additionally, a signiifcantly higher relative cell viability of attached RBCs and thicker mucilage layers were observed in ifgleaf gourd. These results suggest that RBCs play an important role in protecting root tips from CA toxicity. 展开更多
关键词 cinnamon acid AUTOTOXICITY root border cells cell viability
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Identification of a Newly Isolated Getah Virus in the China-Laos Border,China 被引量:12
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作者 LI Yuan Yuan FU Shi Hong +12 位作者 GUO Xiao Fang LEI Wen Wen LI Xiao Long SONG Jing Dong CAO Lei GAO Xiao Yan LYU Zhi HE Ying WANG Huan Yu REN Xiao Jie ZHOU Hong Ning WANG Gui Qin LIANG Guo Dong 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2017年第3期210-214,共5页
In this study, we isolated a virus strain (YN12031) from specimens of Armigeres subalbatus collected in the China-Laos border. BHK-21 cells infected with YN12031 exhibited an evident cytopathic effect (CPE) 32 h p... In this study, we isolated a virus strain (YN12031) from specimens of Armigeres subalbatus collected in the China-Laos border. BHK-21 cells infected with YN12031 exhibited an evident cytopathic effect (CPE) 32 h post-infection. The virus particles were spherical, 70 nm in diameter, and enveloped; they also featured surface fibers. 展开更多
关键词 Getah virus China-Laos border Phenotypic characteristics Molecular evolution
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Developmental characteristics and response to iron toxicity of root border cells in rice seedlings 被引量:9
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作者 Cheng-hua XING Mei-hong ZHU +3 位作者 Miao-zhen CAI Peng LIU Gen-di XU Shao-hui WU 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2008年第3期261-264,共4页
To investigate the Fe^2+ effects on root tips in rice plant, experiments were carried out using border cells in vitro. The border cells were pre-planted in aeroponic culture and detached from root tips. Most border c... To investigate the Fe^2+ effects on root tips in rice plant, experiments were carried out using border cells in vitro. The border cells were pre-planted in aeroponic culture and detached from root tips. Most border cells have a long elliptical shape. The number and the viability of border cells in situ reached the maxima of 1600 and 97.5%, respectively, at 20---25 mm root length. This mortality was more pronounced at the first 1-12 h exposure to 250 mg/L Fe^2+ than at the last 12-36 h. After 36 h, the cell viability exposed to 250 mg/L Fe^2+ decreased to nought, whereas it was 46.5% at 0 mg/L Fe^2+. Increased Fe^2+ dosage stimulated the death of detached border cells from rice cultivars. After 4 h Fe^2+ treatment, the cell viabilities were _〉80% at 0 and 50 mg/L Fe^2+ treatment and were 〈62% at 150, 250 and 350 mg/L Fe^2+ treatment; The viability of border cells decreased by 10% when the Fe^2+ concentration increased by 100 mg/L. After 24 h Fe^2+ treatment, the viabilities of border cells at all the Fe^2+ levels were 〈65%; The viability of border cells decreased by 20% when the Fee+ concentration increased by 100 mg/L. The decreased viabilities of border cells indicated that Fe^2+ dosage and treatment time would cause deadly effect on the border cells. The increased cell death could protect the root tips from toxic harm. Therefore, it may protect root from the damage caused by harmful iron toxicity. 展开更多
关键词 Rice plant border cells Iron toxicity
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