This study showed that difference in students’perceptions toward ability grouping existed.Even though teachers and scholars expected that ability grouping could help students to become more positive motivated and sat...This study showed that difference in students’perceptions toward ability grouping existed.Even though teachers and scholars expected that ability grouping could help students to become more positive motivated and satisfied with studying in the class thus narrowing the gap between advanced and beginning level students,there were still problems showing that ability grouping should be modified.展开更多
Zhalong National Nature Reserve （Zhalong） is an important stopover for migratory birds. In recent decades, Zhalong has become the focus of researchers and public discussion in relation to irrigation. We studied rela...Zhalong National Nature Reserve （Zhalong） is an important stopover for migratory birds. In recent decades, Zhalong has become the focus of researchers and public discussion in relation to irrigation. We studied relationships between birds and habitats at different water levels to guide development of more effective habitat management measures. We used line transects to survey bird numbers and distribution during April-May from 2005-2009 at Zhalong, and used cluster analysis and Chi-Square tests to analyze data. We recorded 139 bird species of 39 families and 13 orders during spring migration, including Anseriformes, Charadriiformes, Ciconiiformes, Columbiformes, Coraciiformes, Cucu- liformes, Falconiformes, Galliformes, Gruiformes, Passeriformes, Pici- formes, Podicipediformes, Strigiformes. Dominant vegetation and geo- graphic region were the main influence factors of avian distribution. Different ecological groups preferred different water levels （p〈0.01） and different habitat types （p〈0.01）. Grallatores, Natatores and Passeres were the main ecological groups in different wetland habitats, and reed marsh and lake are the main habitats for management. Grallatores preferred reed marsh and lake with water levels 〉30 cm and 5-15 cm. Natatores preferred lakes with deep water （〉30 cm）. Passeres preferred open forest and reed marsh with no surface water. Different avian ecological groups occupied specific habitats depending on water level and we recorded some overlaps in bird distribution.展开更多
This paper investigates the breaking point between fast- and slow-light in a degenerate two-level atomic system, where fast-light can be converted to slow-light arbitrarily on a single transition line by adjusting the...This paper investigates the breaking point between fast- and slow-light in a degenerate two-level atomic system, where fast-light can be converted to slow-light arbitrarily on a single transition line by adjusting the strength of the pumping field. An equivalent incoherent pumping rate is introduced in this simplified theoretical model which exploits the dependence of this feature. The experimental observation is presented as evidence of the breaking point where the injected power is about 0.08 mW.展开更多
In order to improve the efficiency of data distributed management service in distributed interactive simulation based on high level architecture (HLA) and to reduce the network traffic and save the system resource, th...In order to improve the efficiency of data distributed management service in distributed interactive simulation based on high level architecture (HLA) and to reduce the network traffic and save the system resource, the approaches of multicast grouping in HLA-based distributed interactive simulation are discussed. Then a new dynamic multicast grouping approach is proposed. This approach is based on the current publication and subscription region in the process of simulation. The results of simulation experiment show that this approach can significantly reduce the message overhead and use fewer multicast groups.展开更多
文摘This study showed that difference in students’perceptions toward ability grouping existed.Even though teachers and scholars expected that ability grouping could help students to become more positive motivated and satisfied with studying in the class thus narrowing the gap between advanced and beginning level students,there were still problems showing that ability grouping should be modified.
基金supported by the Fundamental Research Funds for the Central Universities (No. DL12EA04 and DL11BA01)National Natural Science Foundation of China (No.31070345 and 30670350)+1 种基金China Postdoctoral Science Foundation (No.2011M500631)Heilongjiang Postdoctoral Foundation (No.520-415268)
文摘Zhalong National Nature Reserve （Zhalong） is an important stopover for migratory birds. In recent decades, Zhalong has become the focus of researchers and public discussion in relation to irrigation. We studied relationships between birds and habitats at different water levels to guide development of more effective habitat management measures. We used line transects to survey bird numbers and distribution during April-May from 2005-2009 at Zhalong, and used cluster analysis and Chi-Square tests to analyze data. We recorded 139 bird species of 39 families and 13 orders during spring migration, including Anseriformes, Charadriiformes, Ciconiiformes, Columbiformes, Coraciiformes, Cucu- liformes, Falconiformes, Galliformes, Gruiformes, Passeriformes, Pici- formes, Podicipediformes, Strigiformes. Dominant vegetation and geo- graphic region were the main influence factors of avian distribution. Different ecological groups preferred different water levels （p〈0.01） and different habitat types （p〈0.01）. Grallatores, Natatores and Passeres were the main ecological groups in different wetland habitats, and reed marsh and lake are the main habitats for management. Grallatores preferred reed marsh and lake with water levels 〉30 cm and 5-15 cm. Natatores preferred lakes with deep water （〉30 cm）. Passeres preferred open forest and reed marsh with no surface water. Different avian ecological groups occupied specific habitats depending on water level and we recorded some overlaps in bird distribution.
基金Project supported by the Key Program of the National Natural Science Foundation of China (Grant No.60837004)the Key Project of Jiangxi Electric Power Company (Grant Nos.200950801 and 200950802)
文摘This paper investigates the breaking point between fast- and slow-light in a degenerate two-level atomic system, where fast-light can be converted to slow-light arbitrarily on a single transition line by adjusting the strength of the pumping field. An equivalent incoherent pumping rate is introduced in this simplified theoretical model which exploits the dependence of this feature. The experimental observation is presented as evidence of the breaking point where the injected power is about 0.08 mW.
文摘In order to improve the efficiency of data distributed management service in distributed interactive simulation based on high level architecture (HLA) and to reduce the network traffic and save the system resource, the approaches of multicast grouping in HLA-based distributed interactive simulation are discussed. Then a new dynamic multicast grouping approach is proposed. This approach is based on the current publication and subscription region in the process of simulation. The results of simulation experiment show that this approach can significantly reduce the message overhead and use fewer multicast groups.
