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
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
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
“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
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
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
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
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
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
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
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
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
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
Recent discoveries of ophiolites indicate that there must be a Palaeotethyan geosuture zone bordering China and Vietnam, which separates the Vietbac block from the South China subcontinent. The Indosinian foreland fol...Recent discoveries of ophiolites indicate that there must be a Palaeotethyan geosuture zone bordering China and Vietnam, which separates the Vietbac block from the South China subcontinent. The Indosinian foreland fold-and-thrust belt bordering Yunnan and Guangxi provided further evidence for the palaeotethysides. The oceanic crust was subducted southwestwards while the magmatic arc migrated northeastwards, and the continent-arc collision occurred in the Late Triassic with the thrusting being extended towards the north or northeast. The features of thrust-nappe structure are discussed, which proved the continental margin of the Palaeotethyan ocean there to be a complicated one. A face-to-face collision occurred first along the NW-striking segment and then along the ENE-striking segment accompanied by transpression or oblique thrusting occurring along the NW-striking one.展开更多
Although it has been widely applied in China,flower border has great development potentials,and it is significant for the construction of eco-city to explore favorable flower borders fit for China.On the basis of intr...Although it has been widely applied in China,flower border has great development potentials,and it is significant for the construction of eco-city to explore favorable flower borders fit for China.On the basis of introducing classification and components of flower border,this paper discusses key points of flower border design from the perspectives of planar and three-dimensional layouts,seasonal aspect,color,background and edge decoration,and puts forward major problems in the current flower border application.More indigenous species should be introduced into flower border designs to present works characterized by"localization of plant application,diversified landscape expression,and intensive construction and management".展开更多
In this paper we report a kind of fast-scale instability occurring in the single-ended primary inductance converter (SEPIC) power factor pre-regulator, which is designed to operate in discontinuous conduction mode. ...In this paper we report a kind of fast-scale instability occurring in the single-ended primary inductance converter (SEPIC) power factor pre-regulator, which is designed to operate in discontinuous conduction mode. Main results are given by exact cycle-by-cycle computer simulations as well as theoretical analysis. It is found that the instability phenomenon manifests itself as a fast-scale bifurcation at the switching period, which implies the occurrence of border collision bifurcation, or is related to the transition of the regular operating mode of the SEPIC. According to the theoretical analysis and simulation results, the effects of parameters on system stability, and the locations of the bifurcation points are confirmed. Moreover, the effects of such an instability on power factor and switching stress are also discussed. Finally, the occurrence of the asymmetric bifurcation locations is investigated. The results show that this work provides a convenient means of predicting stability boundaries which can facilitate the selection of the practical parameters.展开更多
At UTC 2017-11-12 18:18:17,an Mw7.3 earthquake occurred at the border between Iran and Iraq(location 34.886°N,45.941°E,depth 23 km according to USGS).We carried out focal mechanism and rupture process studie...At UTC 2017-11-12 18:18:17,an Mw7.3 earthquake occurred at the border between Iran and Iraq(location 34.886°N,45.941°E,depth 23 km according to USGS).We carried out focal mechanism and rupture process studies with the data from IRIS data center,using 26 far-field P-waveforms and 25 SH-waveforms with high S/N ratio and relatively even azimuth coverage(epicentral distance)in a point source model to invert for the focal mechanism solution;the result(Figure1)was used to construct a finite fault model for rupture process inversion(Yao and Ji,1997;Wang et al.,2008),resulting in a preliminary slip distribution of this earthquake(Figures 2-4).The calculated seismic moment is 1.1×1020 N·m,Mw=7.3.The maximum slip is about 700 cm.展开更多
Under the current government strategy of building a Silk Road economic belt, tourism in Chinese border counties has becoming increasingly popular. Studying tourism competitiveness in Chinese border counties is of siza...Under the current government strategy of building a Silk Road economic belt, tourism in Chinese border counties has becoming increasingly popular. Studying tourism competitiveness in Chinese border counties is of sizable theoretical and practical importance, as there are several notable factors involved. In this study, we constructed a tourism competitiveness evaluation model based on eight factors: natural environment, tourism resource, location and transportation, social environment, tourism service facility, border port, tourism industrial cluster and tourism market. We then analyzed the spatial characteristics of tourism competitiveness in border counties and identified five types of border counties: resource advantage type(RA), border-port advantage type(PA), location advantage type(LA), agglomeration advantage type(AA), and relative balance type(RB), and examined the correlation between tourism market competitiveness and interior competitiveness factors in the counties from 2006 to 2011. Results showed that tourism resource, location and transportation, and tourism service facility are the most important competition factors for RA border counties during the study period. Competition factors in PA counties transferred from tourism resource, social environment and tourism service facility to border port and tourism industrial cluster; competition factors in LA counties transferred from natural environment and tourism resource to tourism service facility and tourism industrial cluster and border port. Competition factors in AA counties transferred from tourism service facility to tourism resource. Tourism industrial cluster, tourism service facility and tourism resource proved to be important competition factors in RB counties. The findings of this study can be used to target tourism strategies according to different county types.展开更多
基金National Training Programs of Innovation and Entrepreneurship for Undergraduates(202312216029)2022 Training Programs of Innovation and Entrepreneurship for Undergraduates of Anhui Province(S202212216122)+1 种基金Key Research Project of Natural Sciences in Universities of Anhui Province(2023AH051816)General Teaching Research Project of Anhui Province(2022jyxm665).
文摘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.
基金Under the auspices of National Natural Science Foundation of China(No.42071162,42101165)。
文摘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.
基金Sponsored by Landscape Value Evaluation of Perennial Flower Border Application for Open Field Cultivation in Hefei City(S202212216134)Natural Science Key Research Program for Colleges and Universities in Anhui Province(2023AH051816)Anhui General Teaching Research Project(2022jyxm665).
文摘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.
文摘“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%.
文摘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.
基金the National Innovation Training Project for College Students of Anhui Xinhua University in 2023(202312216028)Provincial Innovation Training Project for College Students of Anhui Xinhua University in 2022(S202212216121)+1 种基金Key Research Project of Natural Science in Universities of Anhui Province(2023AH051816)General Teaching Research Project of Anhui Province(2022jyxm665).
文摘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.
文摘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.
文摘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.
基金Supported by Foundation of Qinhuangdao Bureau of Science and Technology (201101A216)Research Program of Hebei Provincial Department of Science and Technology (11276742)~~
文摘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.
文摘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.
基金supported by the National Basic Research Program of China(973 Program2009CB1190002)the National Key Technology R&D Program of China(2011BAD12B01)
文摘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.
基金supported by grants from National Natural Science Foundation of China(81290342 and 81501757)Development Grant of State Key Laboratory of Infectious Disease Prevention and Control(2014SKLID103)the Special National Project on Research and Development of Key Biosafety Technologies(2016YFC1201900),China
文摘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.
基金Project (Nos. Y307535 and Y304185) supported by the Natural Science Foundation of Zhejiang Province,China
文摘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.
文摘Recent discoveries of ophiolites indicate that there must be a Palaeotethyan geosuture zone bordering China and Vietnam, which separates the Vietbac block from the South China subcontinent. The Indosinian foreland fold-and-thrust belt bordering Yunnan and Guangxi provided further evidence for the palaeotethysides. The oceanic crust was subducted southwestwards while the magmatic arc migrated northeastwards, and the continent-arc collision occurred in the Late Triassic with the thrusting being extended towards the north or northeast. The features of thrust-nappe structure are discussed, which proved the continental margin of the Palaeotethyan ocean there to be a complicated one. A face-to-face collision occurred first along the NW-striking segment and then along the ENE-striking segment accompanied by transpression or oblique thrusting occurring along the NW-striking one.
文摘Although it has been widely applied in China,flower border has great development potentials,and it is significant for the construction of eco-city to explore favorable flower borders fit for China.On the basis of introducing classification and components of flower border,this paper discusses key points of flower border design from the perspectives of planar and three-dimensional layouts,seasonal aspect,color,background and edge decoration,and puts forward major problems in the current flower border application.More indigenous species should be introduced into flower border designs to present works characterized by"localization of plant application,diversified landscape expression,and intensive construction and management".
文摘In this paper we report a kind of fast-scale instability occurring in the single-ended primary inductance converter (SEPIC) power factor pre-regulator, which is designed to operate in discontinuous conduction mode. Main results are given by exact cycle-by-cycle computer simulations as well as theoretical analysis. It is found that the instability phenomenon manifests itself as a fast-scale bifurcation at the switching period, which implies the occurrence of border collision bifurcation, or is related to the transition of the regular operating mode of the SEPIC. According to the theoretical analysis and simulation results, the effects of parameters on system stability, and the locations of the bifurcation points are confirmed. Moreover, the effects of such an instability on power factor and switching stress are also discussed. Finally, the occurrence of the asymmetric bifurcation locations is investigated. The results show that this work provides a convenient means of predicting stability boundaries which can facilitate the selection of the practical parameters.
基金supported by the National Natural Science Foundation of China (grants 41630210 and 41474036)
文摘At UTC 2017-11-12 18:18:17,an Mw7.3 earthquake occurred at the border between Iran and Iraq(location 34.886°N,45.941°E,depth 23 km according to USGS).We carried out focal mechanism and rupture process studies with the data from IRIS data center,using 26 far-field P-waveforms and 25 SH-waveforms with high S/N ratio and relatively even azimuth coverage(epicentral distance)in a point source model to invert for the focal mechanism solution;the result(Figure1)was used to construct a finite fault model for rupture process inversion(Yao and Ji,1997;Wang et al.,2008),resulting in a preliminary slip distribution of this earthquake(Figures 2-4).The calculated seismic moment is 1.1×1020 N·m,Mw=7.3.The maximum slip is about 700 cm.
基金National Natural Science Foundation of China(No.41171435)
文摘Under the current government strategy of building a Silk Road economic belt, tourism in Chinese border counties has becoming increasingly popular. Studying tourism competitiveness in Chinese border counties is of sizable theoretical and practical importance, as there are several notable factors involved. In this study, we constructed a tourism competitiveness evaluation model based on eight factors: natural environment, tourism resource, location and transportation, social environment, tourism service facility, border port, tourism industrial cluster and tourism market. We then analyzed the spatial characteristics of tourism competitiveness in border counties and identified five types of border counties: resource advantage type(RA), border-port advantage type(PA), location advantage type(LA), agglomeration advantage type(AA), and relative balance type(RB), and examined the correlation between tourism market competitiveness and interior competitiveness factors in the counties from 2006 to 2011. Results showed that tourism resource, location and transportation, and tourism service facility are the most important competition factors for RA border counties during the study period. Competition factors in PA counties transferred from tourism resource, social environment and tourism service facility to border port and tourism industrial cluster; competition factors in LA counties transferred from natural environment and tourism resource to tourism service facility and tourism industrial cluster and border port. Competition factors in AA counties transferred from tourism service facility to tourism resource. Tourism industrial cluster, tourism service facility and tourism resource proved to be important competition factors in RB counties. The findings of this study can be used to target tourism strategies according to different county types.