It is known that intangible cultural heritage is an important resource of the cultural soft power in a country, and it is also an organic component and representation of national history, spirit and cohesion.Therefore...It is known that intangible cultural heritage is an important resource of the cultural soft power in a country, and it is also an organic component and representation of national history, spirit and cohesion.Therefore, a good inheritance of intangible cultural heritage is of great significance for carrying forward the ethical basis of human culture as well as maintaining its value core. Nowadays, the rapid intelligentization of media has ushered in the era of intellectual media, with characteristics of “massive media, man-machine integration and self-evolution”. In the era of intellectual media, traces of intelligent technologies can be seen everywhere, and the ecology of the inheritance of intangible cultural heritage has been reconstructed. Under this circumstance, the author firstly makes clarification of the advancement of the era, which has given a new logic of intangible cultural heritage inheritance, and various intelligent powers should be developed including intelligent acquisition, processing and judgement ability of content value. Then, the technology empowerment is analyzed, which has made reconstruction of intangible cultural heritage inheritance: while being digitalized,the inheritance of intangible cultural heritage has become systematized in way of “Points, Lines and Planes” at the same time. Therefore, the communication ecology of intangible cultural heritage could be established as a new approach of inheritance via all sorts of intelligent technologies, so as to promote Chinese cultural soft power and enhance our national image in the long run.展开更多
This study takes the image of China’s military as c onstructed in the British media’s military coverage of China as an object of study,and creates two reference corpora for comparative research.It is used to better ...This study takes the image of China’s military as c onstructed in the British media’s military coverage of China as an object of study,and creates two reference corpora for comparative research.It is used to better analyse and compare the ideologies hidden in the British media’s coverage of China’s milita ry.From the analysis of the corpus,it is concluded that due to China’s rapid military and economic development,Western countries have developed a sense of crisis and have used media reports to instigate China’s foreign relations and mislead public think ing.展开更多
In new media era,the network coverage is wider,application of mobile terminals is more convenient,speed of information dissemination is fully accelerated,scope of dissemination is wider and people's access to info...In new media era,the network coverage is wider,application of mobile terminals is more convenient,speed of information dissemination is fully accelerated,scope of dissemination is wider and people's access to information is more diversified.Therefore,the current media has become an indispensable part of human’s lives such as changing the way human live,work,learn and communicate daily.In this context,it is compulsory to improve the traditional teaching methods in order to keep in pace with the fast development and promote art education through the combination of technology and art.This paper analyses the current situation of digital media art teaching and the construction path of teaching model in the new media era.展开更多
New media have exerted profound influence on the core values of contemporary college students. In the new media era, in order to cultivate and practice the social core values, we have to transform the concept and meth...New media have exerted profound influence on the core values of contemporary college students. In the new media era, in order to cultivate and practice the social core values, we have to transform the concept and method of education. It is also important to realize the positive and negative influence of core values on both college students and teachers, so that the education on social core values can be carried out in an active and effective way.展开更多
New media is an important part of the construction of college students' values. The rapid development and extensive application of new media have a positive and negative impact on the ideological behavior of college ...New media is an important part of the construction of college students' values. The rapid development and extensive application of new media have a positive and negative impact on the ideological behavior of college students. In order to cause the university student understanding and the approval socialism core values, we need to use the new media, from aspects and so on with the education idea, propaganda way, education vigor, content construction platform construction constructs the contemporary university student' s correct values.展开更多
Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid ...Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid fatty acid (PLFA) composition. A total of 20 fatty acids in the range of C18to C20 were determined but only 13 PLFAs were detected in steel slag. They consist of saturated fatty acids, branched fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The variation of fatty acids was revealed in the relative proportions of these fatty acids in different media. The aerobic prokaryotes were the predominant group in all media. The PLFA composition showed significant differences among the eight different media by Tukey's honestly test. It was found that steel slag was significantly different in the microbial community as compared to other filter media, probably due to its alkaline effluent. Steel slag alone is probably not a good choice of substratum in constructed wetlands. The principle components analysis (PCA) showed that zeolites, bio-ceramic, shale and vermiculite had a similar microbial community structure while steel slag and ceramic filter media were distinct from other media.展开更多
On the basis of similar structure of solutions of ordinary differential equation (ODE) boundary value problem, the similar construction method was put forward by solving problems of fluid flow in porous media through ...On the basis of similar structure of solutions of ordinary differential equation (ODE) boundary value problem, the similar construction method was put forward by solving problems of fluid flow in porous media through the homogeneous reservoir. It is indicate that the pressure distribution of dimensionless reservoir and bottom hole in Laplace space, which take on the radial flow, also shows similar structure, and the internal relationship between the above solutions were illustrated in detail.展开更多
Urban construction land suitability evaluation (UCLSE) is a complex system engineering and the basis for rational use of the limited urban land resources in China. It has an important practical value on urban constr...Urban construction land suitability evaluation (UCLSE) is a complex system engineering and the basis for rational use of the limited urban land resources in China. It has an important practical value on urban construction land use planning and management from the angle of methodology. As a widely used technique, traditional multi-criteria evaluation based on GIS (MCE-GIS), is not suitable for UCLSE. This study develops an improved MCE-GIS method which could be more suitable for UCLSE based on urban complex ecological system theory and the summary of the shortcomings of traditional MCE-GIS. The improvements include three aspects: a composite evaluation index system rather than natural indexes alone, an index weight calculated by using fuzzy Analytic Hierarchy Process (AHP) method rather than the common AHP method, and the integrated overlay rule, which includes selecting the minimum value, weighted linear combination (WLC) and simple summation. The main advantage of this improved technique is that it can make UCLSE more comprehensive, more operational and more reasonable. It can provide a scientific basis for decision making in the planning and management of urban construction land use. The improved MCE-GIS system has been adopted in the New Hefei City, Anhui Province, China. Based on the results of UCLSE in New Hefei, three functional areas including construction-appropriate areas, construction-restricted areas and construction-forbidden areas could be worked out, in which 36.90% of the total study area could be developed as urban construction land and the remaining 63.10% should be protected as reserves land or as ecological land. Furthermore, the results can orovide scientific decision suooort for spatial planning and eco-environment nrotection in New Hefei.展开更多
Weibo,one of China’s largest digital media platforms,has become a major platform for women’s voices to fight for equality.However,misconceptions of feminism on Weibo have become obstacles to women’s voices,for whic...Weibo,one of China’s largest digital media platforms,has become a major platform for women’s voices to fight for equality.However,misconceptions of feminism on Weibo have become obstacles to women’s voices,for which the platforms did not post women’s views prominently.From the perspective of women themselves,this paper adopted a questionnaire to study the misunderstanding of feminism and its impact on women’s expression on Weibo.展开更多
Rural tourism was a new form of tourism gradually emerging in China in recent years. It satisfied urban residents' pursuit of nature and had a promising market prospect. New rural construction of socialism was an ...Rural tourism was a new form of tourism gradually emerging in China in recent years. It satisfied urban residents' pursuit of nature and had a promising market prospect. New rural construction of socialism was an important historical task in the process of economic and social development of China at present and in future period. New rural construction was the important basis of rural tourism development and meanwhile rural tourism development could promote new rural construction. Shanxi Merchant's Culture of Xi Village in Jinzhong City was a kind of excellent rural tourism resource. Developing rural tourism was one of the effective ways to promote new rural construction of socialism in Xi Village.展开更多
In northern China’s agro-pastoral ecotone,there are conflicts between agricultural industry and ecological construction resource competition,and also problems urgently to be solved for economic growth and sustainable...In northern China’s agro-pastoral ecotone,there are conflicts between agricultural industry and ecological construction resource competition,and also problems urgently to be solved for economic growth and sustainable ecological improvement.Taking the development concept of"lucid waters and lush mountains being mountains of gold and silver"as the guiding principle of prioritizing ecological and green development,this paper studied the strategies for prioritizing ecological construction with consideration of economic development of agricultural industry from the perspective of opportunity cost.Through the analysis of opportunity cost,externality,and Pareto optimal theory,and using the calculation method of the unit equivalent factor value of terrestrial ecological service function,this paper calculated the ecological service value of forest,grassland,and farmland.It found that the ecological value of forest and grassland per unit area was greater than the ecological value of agricultural industry.This indicates that the opportunity cost of farmland for ecological construction was less than that of agricultural industry.Based on the theoretical and quantitative analysis,it came up with recommendations for establishing a comprehensive system for prioritizing ecological construction with consideration of agricultural industry development and establishing and improving the incentive mechanism of ecological construction.展开更多
This paper presents a simplified graphical procedure for constructing, using an unmarked straightedge and a compass only, a 10˚ to 20˚ angle, which is in other words, trisecting a 30˚ or 60˚ angle. The procedure, when...This paper presents a simplified graphical procedure for constructing, using an unmarked straightedge and a compass only, a 10˚ to 20˚ angle, which is in other words, trisecting a 30˚ or 60˚ angle. The procedure, when applied to the 30˚ and 60˚ angles that have been “proven” to be not trisectable, produced a construction having the identical angular relationship with Archimedes’ Construction, in which the required trisection angles were found to be 10.00000˚ and 20.00000˚ respectively (i.e. exactly one-third of the given angle or ∠E’MA = 1/3∠E’CG). Based on this identical angular relationship as well as the numerical results obtained, one can only conclude that the geometric requirements for arriving at an exact trisection of the 30˚ or 60˚ angle, and therefore the construction of a 10˚ or 20˚ angle, have been met, notwithstanding the theoretical proofs of Wantzel, Dudley, and others. Thus, the solution to the age-old trisection problem, with respect to these two angles, has been accomplished.展开更多
The seepage characteristics of multiscale porous media is of considerable significance in many scientific and engineering fields.The Darcy permeability is one of the key macroscopic physical properties to characterize...The seepage characteristics of multiscale porous media is of considerable significance in many scientific and engineering fields.The Darcy permeability is one of the key macroscopic physical properties to characterize the seepage capacity of porous media.Therefore,based on the statistically fractal scaling law of porous media,fractal geometry is applied to model the multiscale pore structures.And a two-dimensional fractal orifice-throat model with multiscale and tortuous characteristics is proposed for the seepage flow through porous media.The analytical expression for Darcy permeability of porous media is derived,which is validated by comparing with available experimental data.The results show that the Darcy permeability is significantly influenced by porosity,orifice-throat fractal dimension,minimum to maximum diameter ratio,orifice-throat ratio and tortuosity fractal dimension.The present results are helpful for understanding the seepage mechanism of multiscale porous media,and may provide theoretical basis for unconventional oil and gas exploration and development,porous phase transition energy storage composites,CO2 geological sequestration,environmental protection and nuclear waste treatment,etc.展开更多
The public’s attitudes can affect the experience of stuttering of people who stutter.This study investigated the attitudes held by the public about people who stutter in China.A web-based written survey with closed a...The public’s attitudes can affect the experience of stuttering of people who stutter.This study investigated the attitudes held by the public about people who stutter in China.A web-based written survey with closed and open-ended questions was implemented to develop a rich understanding.One hundred and two respondents in 26 provinces and 3 municipalities provided comments on people who stutter in their life aspects such as personality,speech,social life,work,life participation,education,dating and marriage,capability,and communication skills.The predominantly negative attitudes towards the overall domains were identified.Attitudes to people who stutter varied according to the different sources of knowledge.Familiarity with people who stutter might reduce stereotypes.However,knowledge from the media might aggravate stereotypes.Implications and future research orientation were also discussed.展开更多
1. Concept of People's Livelihood in Traditional Chinese Culture The concept of human rights was borrowed from the West. In order to have it become rooted in China, people needed to find traces in Chinese culture on ...1. Concept of People's Livelihood in Traditional Chinese Culture The concept of human rights was borrowed from the West. In order to have it become rooted in China, people needed to find traces in Chinese culture on which the human rights theoretical system could be based and the Chinese human rights idea could be realized.展开更多
Screening humanized antibodies from a human Fab phage display library is an effective and quick method to obtain beta-amyloid oligomers. Thus, the present study prepared amyloid-beta 42 oli- gomers and constructed a h...Screening humanized antibodies from a human Fab phage display library is an effective and quick method to obtain beta-amyloid oligomers. Thus, the present study prepared amyloid-beta 42 oli- gomers and constructed a have human Fab phage display library based on blood samples from six healthy people. After three rounds of biopanning in vitro, a human single-domain antibody that spe- cifically recognized amyloid-beta 42 oligomers was identified. Western blot and enzyme-linked im- munosorbent assay demonstrated this antibody bound specifically to human amyloid-beta 42 tetramer and nonamer, but not the monomer or high molecular weight oligomers. This study suc- cessfully constructed a human phage display library and screened a single-domain antibody that specifically recognized amyloid-beta 42 oligomers.展开更多
With China’s entry into WTO and the development of the economic globalization, market competition in the construction field is more and more featured by the competition of talents, the core of which is the cultivatio...With China’s entry into WTO and the development of the economic globalization, market competition in the construction field is more and more featured by the competition of talents, the core of which is the cultivation mechanism innovation of higher construction management talents. The approach to meet the requirement of this situation is to adopt innovation ideas, improve the supply-demand structure of CME, reform the education system to relate theory to practice, pay attention to the needs of the educated, enhance global communication and cooperation, and improve the knowledge structure of teachers.展开更多
文摘It is known that intangible cultural heritage is an important resource of the cultural soft power in a country, and it is also an organic component and representation of national history, spirit and cohesion.Therefore, a good inheritance of intangible cultural heritage is of great significance for carrying forward the ethical basis of human culture as well as maintaining its value core. Nowadays, the rapid intelligentization of media has ushered in the era of intellectual media, with characteristics of “massive media, man-machine integration and self-evolution”. In the era of intellectual media, traces of intelligent technologies can be seen everywhere, and the ecology of the inheritance of intangible cultural heritage has been reconstructed. Under this circumstance, the author firstly makes clarification of the advancement of the era, which has given a new logic of intangible cultural heritage inheritance, and various intelligent powers should be developed including intelligent acquisition, processing and judgement ability of content value. Then, the technology empowerment is analyzed, which has made reconstruction of intangible cultural heritage inheritance: while being digitalized,the inheritance of intangible cultural heritage has become systematized in way of “Points, Lines and Planes” at the same time. Therefore, the communication ecology of intangible cultural heritage could be established as a new approach of inheritance via all sorts of intelligent technologies, so as to promote Chinese cultural soft power and enhance our national image in the long run.
文摘This study takes the image of China’s military as c onstructed in the British media’s military coverage of China as an object of study,and creates two reference corpora for comparative research.It is used to better analyse and compare the ideologies hidden in the British media’s coverage of China’s milita ry.From the analysis of the corpus,it is concluded that due to China’s rapid military and economic development,Western countries have developed a sense of crisis and have used media reports to instigate China’s foreign relations and mislead public think ing.
文摘In new media era,the network coverage is wider,application of mobile terminals is more convenient,speed of information dissemination is fully accelerated,scope of dissemination is wider and people's access to information is more diversified.Therefore,the current media has become an indispensable part of human’s lives such as changing the way human live,work,learn and communicate daily.In this context,it is compulsory to improve the traditional teaching methods in order to keep in pace with the fast development and promote art education through the combination of technology and art.This paper analyses the current situation of digital media art teaching and the construction path of teaching model in the new media era.
文摘New media have exerted profound influence on the core values of contemporary college students. In the new media era, in order to cultivate and practice the social core values, we have to transform the concept and method of education. It is also important to realize the positive and negative influence of core values on both college students and teachers, so that the education on social core values can be carried out in an active and effective way.
文摘New media is an important part of the construction of college students' values. The rapid development and extensive application of new media have a positive and negative impact on the ideological behavior of college students. In order to cause the university student understanding and the approval socialism core values, we need to use the new media, from aspects and so on with the education idea, propaganda way, education vigor, content construction platform construction constructs the contemporary university student' s correct values.
基金supported by the National Natural Science Foundation of China (No.30870221,20877093,50808172)the High Technology Research and Development Program (863) of China (No.2009X207209-004)
文摘Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid fatty acid (PLFA) composition. A total of 20 fatty acids in the range of C18to C20 were determined but only 13 PLFAs were detected in steel slag. They consist of saturated fatty acids, branched fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The variation of fatty acids was revealed in the relative proportions of these fatty acids in different media. The aerobic prokaryotes were the predominant group in all media. The PLFA composition showed significant differences among the eight different media by Tukey's honestly test. It was found that steel slag was significantly different in the microbial community as compared to other filter media, probably due to its alkaline effluent. Steel slag alone is probably not a good choice of substratum in constructed wetlands. The principle components analysis (PCA) showed that zeolites, bio-ceramic, shale and vermiculite had a similar microbial community structure while steel slag and ceramic filter media were distinct from other media.
文摘On the basis of similar structure of solutions of ordinary differential equation (ODE) boundary value problem, the similar construction method was put forward by solving problems of fluid flow in porous media through the homogeneous reservoir. It is indicate that the pressure distribution of dimensionless reservoir and bottom hole in Laplace space, which take on the radial flow, also shows similar structure, and the internal relationship between the above solutions were illustrated in detail.
基金Under the auspices of National Natural Science Foundation of China(No.41201168)Fundamental Research Funds for the Central Universities(No.2013HGXJ0207)
文摘Urban construction land suitability evaluation (UCLSE) is a complex system engineering and the basis for rational use of the limited urban land resources in China. It has an important practical value on urban construction land use planning and management from the angle of methodology. As a widely used technique, traditional multi-criteria evaluation based on GIS (MCE-GIS), is not suitable for UCLSE. This study develops an improved MCE-GIS method which could be more suitable for UCLSE based on urban complex ecological system theory and the summary of the shortcomings of traditional MCE-GIS. The improvements include three aspects: a composite evaluation index system rather than natural indexes alone, an index weight calculated by using fuzzy Analytic Hierarchy Process (AHP) method rather than the common AHP method, and the integrated overlay rule, which includes selecting the minimum value, weighted linear combination (WLC) and simple summation. The main advantage of this improved technique is that it can make UCLSE more comprehensive, more operational and more reasonable. It can provide a scientific basis for decision making in the planning and management of urban construction land use. The improved MCE-GIS system has been adopted in the New Hefei City, Anhui Province, China. Based on the results of UCLSE in New Hefei, three functional areas including construction-appropriate areas, construction-restricted areas and construction-forbidden areas could be worked out, in which 36.90% of the total study area could be developed as urban construction land and the remaining 63.10% should be protected as reserves land or as ecological land. Furthermore, the results can orovide scientific decision suooort for spatial planning and eco-environment nrotection in New Hefei.
文摘Weibo,one of China’s largest digital media platforms,has become a major platform for women’s voices to fight for equality.However,misconceptions of feminism on Weibo have become obstacles to women’s voices,for which the platforms did not post women’s views prominently.From the perspective of women themselves,this paper adopted a questionnaire to study the misunderstanding of feminism and its impact on women’s expression on Weibo.
文摘Rural tourism was a new form of tourism gradually emerging in China in recent years. It satisfied urban residents' pursuit of nature and had a promising market prospect. New rural construction of socialism was an important historical task in the process of economic and social development of China at present and in future period. New rural construction was the important basis of rural tourism development and meanwhile rural tourism development could promote new rural construction. Shanxi Merchant's Culture of Xi Village in Jinzhong City was a kind of excellent rural tourism resource. Developing rural tourism was one of the effective ways to promote new rural construction of socialism in Xi Village.
基金Supported by Project of National Social Science Foundation of China(19BSH077).
文摘In northern China’s agro-pastoral ecotone,there are conflicts between agricultural industry and ecological construction resource competition,and also problems urgently to be solved for economic growth and sustainable ecological improvement.Taking the development concept of"lucid waters and lush mountains being mountains of gold and silver"as the guiding principle of prioritizing ecological and green development,this paper studied the strategies for prioritizing ecological construction with consideration of economic development of agricultural industry from the perspective of opportunity cost.Through the analysis of opportunity cost,externality,and Pareto optimal theory,and using the calculation method of the unit equivalent factor value of terrestrial ecological service function,this paper calculated the ecological service value of forest,grassland,and farmland.It found that the ecological value of forest and grassland per unit area was greater than the ecological value of agricultural industry.This indicates that the opportunity cost of farmland for ecological construction was less than that of agricultural industry.Based on the theoretical and quantitative analysis,it came up with recommendations for establishing a comprehensive system for prioritizing ecological construction with consideration of agricultural industry development and establishing and improving the incentive mechanism of ecological construction.
文摘This paper presents a simplified graphical procedure for constructing, using an unmarked straightedge and a compass only, a 10˚ to 20˚ angle, which is in other words, trisecting a 30˚ or 60˚ angle. The procedure, when applied to the 30˚ and 60˚ angles that have been “proven” to be not trisectable, produced a construction having the identical angular relationship with Archimedes’ Construction, in which the required trisection angles were found to be 10.00000˚ and 20.00000˚ respectively (i.e. exactly one-third of the given angle or ∠E’MA = 1/3∠E’CG). Based on this identical angular relationship as well as the numerical results obtained, one can only conclude that the geometric requirements for arriving at an exact trisection of the 30˚ or 60˚ angle, and therefore the construction of a 10˚ or 20˚ angle, have been met, notwithstanding the theoretical proofs of Wantzel, Dudley, and others. Thus, the solution to the age-old trisection problem, with respect to these two angles, has been accomplished.
文摘The seepage characteristics of multiscale porous media is of considerable significance in many scientific and engineering fields.The Darcy permeability is one of the key macroscopic physical properties to characterize the seepage capacity of porous media.Therefore,based on the statistically fractal scaling law of porous media,fractal geometry is applied to model the multiscale pore structures.And a two-dimensional fractal orifice-throat model with multiscale and tortuous characteristics is proposed for the seepage flow through porous media.The analytical expression for Darcy permeability of porous media is derived,which is validated by comparing with available experimental data.The results show that the Darcy permeability is significantly influenced by porosity,orifice-throat fractal dimension,minimum to maximum diameter ratio,orifice-throat ratio and tortuosity fractal dimension.The present results are helpful for understanding the seepage mechanism of multiscale porous media,and may provide theoretical basis for unconventional oil and gas exploration and development,porous phase transition energy storage composites,CO2 geological sequestration,environmental protection and nuclear waste treatment,etc.
文摘The public’s attitudes can affect the experience of stuttering of people who stutter.This study investigated the attitudes held by the public about people who stutter in China.A web-based written survey with closed and open-ended questions was implemented to develop a rich understanding.One hundred and two respondents in 26 provinces and 3 municipalities provided comments on people who stutter in their life aspects such as personality,speech,social life,work,life participation,education,dating and marriage,capability,and communication skills.The predominantly negative attitudes towards the overall domains were identified.Attitudes to people who stutter varied according to the different sources of knowledge.Familiarity with people who stutter might reduce stereotypes.However,knowledge from the media might aggravate stereotypes.Implications and future research orientation were also discussed.
文摘1. Concept of People's Livelihood in Traditional Chinese Culture The concept of human rights was borrowed from the West. In order to have it become rooted in China, people needed to find traces in Chinese culture on which the human rights theoretical system could be based and the Chinese human rights idea could be realized.
基金supported by the National Natural Science Foundation of China,No.30600099(FD)
文摘Screening humanized antibodies from a human Fab phage display library is an effective and quick method to obtain beta-amyloid oligomers. Thus, the present study prepared amyloid-beta 42 oli- gomers and constructed a have human Fab phage display library based on blood samples from six healthy people. After three rounds of biopanning in vitro, a human single-domain antibody that spe- cifically recognized amyloid-beta 42 oligomers was identified. Western blot and enzyme-linked im- munosorbent assay demonstrated this antibody bound specifically to human amyloid-beta 42 tetramer and nonamer, but not the monomer or high molecular weight oligomers. This study suc- cessfully constructed a human phage display library and screened a single-domain antibody that specifically recognized amyloid-beta 42 oligomers.
文摘With China’s entry into WTO and the development of the economic globalization, market competition in the construction field is more and more featured by the competition of talents, the core of which is the cultivation mechanism innovation of higher construction management talents. The approach to meet the requirement of this situation is to adopt innovation ideas, improve the supply-demand structure of CME, reform the education system to relate theory to practice, pay attention to the needs of the educated, enhance global communication and cooperation, and improve the knowledge structure of teachers.