Autonomous learning and its importance has attracted more and more attention,on the basis of which,independent read-ing activities should emphasizes the student as the center in the activity.So the choice of independe...Autonomous learning and its importance has attracted more and more attention,on the basis of which,independent read-ing activities should emphasizes the student as the center in the activity.So the choice of independent reading materials should bebased on their requirement.The materials should have the features of interesting and informative,varied style,content suitable forteaching materials,etc.At last how English teacher guide and conduct the students’activities of self-monitoring and self-assess-ment.展开更多
The diversification of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities and their potential nitrification activity (PNA) on a large scale have not been well documented. In this work, se...The diversification of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities and their potential nitrification activity (PNA) on a large scale have not been well documented. In this work, seven paddy soils from different geographic regions in Sichuan, P. R. China were selected to determine the spatial distribution of the activities, abundances and community compositions of AOB and AOA. PNA varied greatly among paddy soils, and was positively correlated with soil pH (P< 0.05). The abundance of AOA was 81.1 to 1 670.0 times more than that of AOB, which indicates paddy soil environments favor the growth of AOA. Denaturing gradient gel electrophoresis fingerprints of amoA genes exhibited distinct spatial differences in AOA compositions rather than in AOB compositions. Sequencing analysis revealed that acidic soils were dominated by AOA within marine group 1.1 a-associated lineage, whereas the soil group 1.1b lineage AOA predominated in neutral and alkaline soils. Both nitrosopira cluster 3-like and Nitrosomonas cluster 7-like AOB dominated the AOB communities in the paddy soils. Redundancy analysis suggested that soil NH4^+-N content was the most significant driver determining the AOB community structure, while no significant correlation between AOA community structure and soil properties was found. The findings highlight that the activity and composition of ammonia oxidizers exhibit spatial variations in complex paddy fields due to the joint influence of soil variables associated with pH and N availability.展开更多
We review the management of Eucalyptus species under a coppice-with-standards （CWS） silvicultural system. CWS management results in product diversification, permitting production of small and large scale timber from...We review the management of Eucalyptus species under a coppice-with-standards （CWS） silvicultural system. CWS management results in product diversification, permitting production of small and large scale timber from the same stand. Eucalyptus species are suitable candidates for CWS management because： there are large worldwide plantation areas, sprouting capacity is high, and eucalypts are multipur- pose species. We discuss （1） short rotation Eucalyptus coppice manage- ment for energy and pulping and （2） Eucalyptus seedling management for solid wood products. We review the literature and discuss experi- ences with Eucalyptus managed under the CWS system. We also assess projects dealing with Eucalyptus coppice management, stand density regulation, pruning, and stand and wood quality. The growth environ- ment of the standard trees （heavy competition up to the first harvest, free growth afterwards） coupled with long rotations （〉20 years） results in high quality logs for solid wood products. Early pruning should be ap- plied to enhance wood quality. We propose a system for the silvicultural management of Eucalyptus under the CWS system, elaborating on the consequences of initial planting density, site productivity, and standard tree densities as well as timing of basic silvicultural applications.展开更多
Everyday Use is one of the best novels by Alice Walker,who is a famous African American woman writer.It is also the typical work that can reveal the black's attitudes to their culture.In this work,house,fire and q...Everyday Use is one of the best novels by Alice Walker,who is a famous African American woman writer.It is also the typical work that can reveal the black's attitudes to their culture.In this work,house,fire and quilts are the black cultural images.The writer describes the phenomenon that African Americans hold different attitudes to their various cultural images which reveals the African American's living conditions under the diversified culture.展开更多
After thirty years,Shengli Oilfield has become the second largest oil base in China W with an annual production of more than 30 million tons ot oil and over 1.4 billion cubic meters of na tural gas.
Daqing Oilfield is the biggest oilfield in China,as well as one of ten most famous oilfields in.the world.For the past 30 years,its exploration and development of oil and gas and its field con-struction have been marv...Daqing Oilfield is the biggest oilfield in China,as well as one of ten most famous oilfields in.the world.For the past 30 years,its exploration and development of oil and gas and its field con-struction have been marvelously successful.Its con-tribution to Chinese petroleum industry is enor-mous.Its annual 50 million tons crude oil output has been hold on for 18 years since 1976.With the“water controlling,oil maintaining”production sys-tem and scientific management,this stable produc-tion period could be continued to the end of the cen-tury or even more.展开更多
文摘Autonomous learning and its importance has attracted more and more attention,on the basis of which,independent read-ing activities should emphasizes the student as the center in the activity.So the choice of independent reading materials should bebased on their requirement.The materials should have the features of interesting and informative,varied style,content suitable forteaching materials,etc.At last how English teacher guide and conduct the students’activities of self-monitoring and self-assess-ment.
基金Funded by the National Natural Science Foundation of China (No.41606142)the Fundamental Research Funds of China West Normal University (No.463140 and No.412554)
文摘The diversification of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities and their potential nitrification activity (PNA) on a large scale have not been well documented. In this work, seven paddy soils from different geographic regions in Sichuan, P. R. China were selected to determine the spatial distribution of the activities, abundances and community compositions of AOB and AOA. PNA varied greatly among paddy soils, and was positively correlated with soil pH (P< 0.05). The abundance of AOA was 81.1 to 1 670.0 times more than that of AOB, which indicates paddy soil environments favor the growth of AOA. Denaturing gradient gel electrophoresis fingerprints of amoA genes exhibited distinct spatial differences in AOA compositions rather than in AOB compositions. Sequencing analysis revealed that acidic soils were dominated by AOA within marine group 1.1 a-associated lineage, whereas the soil group 1.1b lineage AOA predominated in neutral and alkaline soils. Both nitrosopira cluster 3-like and Nitrosomonas cluster 7-like AOB dominated the AOB communities in the paddy soils. Redundancy analysis suggested that soil NH4^+-N content was the most significant driver determining the AOB community structure, while no significant correlation between AOA community structure and soil properties was found. The findings highlight that the activity and composition of ammonia oxidizers exhibit spatial variations in complex paddy fields due to the joint influence of soil variables associated with pH and N availability.
基金suported by the Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES),through the PSDE program,process number BEX:2939/12-6.
文摘We review the management of Eucalyptus species under a coppice-with-standards （CWS） silvicultural system. CWS management results in product diversification, permitting production of small and large scale timber from the same stand. Eucalyptus species are suitable candidates for CWS management because： there are large worldwide plantation areas, sprouting capacity is high, and eucalypts are multipur- pose species. We discuss （1） short rotation Eucalyptus coppice manage- ment for energy and pulping and （2） Eucalyptus seedling management for solid wood products. We review the literature and discuss experi- ences with Eucalyptus managed under the CWS system. We also assess projects dealing with Eucalyptus coppice management, stand density regulation, pruning, and stand and wood quality. The growth environ- ment of the standard trees （heavy competition up to the first harvest, free growth afterwards） coupled with long rotations （〉20 years） results in high quality logs for solid wood products. Early pruning should be ap- plied to enhance wood quality. We propose a system for the silvicultural management of Eucalyptus under the CWS system, elaborating on the consequences of initial planting density, site productivity, and standard tree densities as well as timing of basic silvicultural applications.
文摘Everyday Use is one of the best novels by Alice Walker,who is a famous African American woman writer.It is also the typical work that can reveal the black's attitudes to their culture.In this work,house,fire and quilts are the black cultural images.The writer describes the phenomenon that African Americans hold different attitudes to their various cultural images which reveals the African American's living conditions under the diversified culture.
文摘After thirty years,Shengli Oilfield has become the second largest oil base in China W with an annual production of more than 30 million tons ot oil and over 1.4 billion cubic meters of na tural gas.
文摘Daqing Oilfield is the biggest oilfield in China,as well as one of ten most famous oilfields in.the world.For the past 30 years,its exploration and development of oil and gas and its field con-struction have been marvelously successful.Its con-tribution to Chinese petroleum industry is enor-mous.Its annual 50 million tons crude oil output has been hold on for 18 years since 1976.With the“water controlling,oil maintaining”production sys-tem and scientific management,this stable produc-tion period could be continued to the end of the cen-tury or even more.
