The effects of grape-tobacco intercropping patterns on populations of grape phylloxera, Daktulosphaira vitifoliae Fitch, as well as on the growth and development of the infested vines were evaluated in the field and t...The effects of grape-tobacco intercropping patterns on populations of grape phylloxera, Daktulosphaira vitifoliae Fitch, as well as on the growth and development of the infested vines were evaluated in the field and the impact of an aqueous tobacco root extract on grape phylloxera was evaluated using a laboratory bioassay. The aqueous tobacco root extract exhibited biological activity against this pest. The egg mortality, nymph mortality, development period, life span and female fecundity were significantly affected. In the field trial, grape phylloxera populations were clearly lower as compared to the monoculture pattern. However, the rates of newly developed roots and newly infested grape roots were significantly higher and lower, in intercropping patterns than in the vine monoculture, respectively. The grape phylloxera population number on the grape roots decreased each year, and the vine trees gradually renewed upon continuous intercropping with tobacco over three years. These results confirmed that intercropping grapes with tobacco can effectively control grape phylloxera in an infested vineyard. The results also indicated that additional crops could be intercropped with grapes and are effective against grape phylloxera, which should be explored as an integrated approach for controlling the pest.展开更多
A perimeter traffic signal control strategy is proposed based on the macroscopic fundamental diagram theory(MFD)to solve the signal control problem in oversaturated states.First,the MFD of a specific regional network ...A perimeter traffic signal control strategy is proposed based on the macroscopic fundamental diagram theory(MFD)to solve the signal control problem in oversaturated states.First,the MFD of a specific regional network can be derived using VSS IM simulation software.Secondly,the maximum number of cumulative vehicles that the network can accommodate is determined based on the MFD.Then,through monitoring the influx flow,the number of vehicles existing in and exiting from the network,a perimeter traffic control model is proposed to optimize the signal timing of the boundary intersections.Finally,a virtual network simulation model is established and three different kinds o f traffic demand are loaded into the network.Simulation results show that a fer the strategy implementation,the number o f vehicles accumulating in the network can be kept near the optimal value,while the number o f both entering and exiting vehicles increases significantly and the road network can be maintained at a large capacity.Simultaneously,the queue length at the approach of the border intersections is reasonably controlled and vehicles entering and exiting the network can maintain a more efficient and stable speed.The network performance indices such as the average traffic delay and average number of stops can be improved to a certain degree,thus verifying the effectiveness and feasibility of the perimeter control strategy.展开更多
基金supported by the Project of National Technology System for Grape Industry (nycytx-30)
文摘The effects of grape-tobacco intercropping patterns on populations of grape phylloxera, Daktulosphaira vitifoliae Fitch, as well as on the growth and development of the infested vines were evaluated in the field and the impact of an aqueous tobacco root extract on grape phylloxera was evaluated using a laboratory bioassay. The aqueous tobacco root extract exhibited biological activity against this pest. The egg mortality, nymph mortality, development period, life span and female fecundity were significantly affected. In the field trial, grape phylloxera populations were clearly lower as compared to the monoculture pattern. However, the rates of newly developed roots and newly infested grape roots were significantly higher and lower, in intercropping patterns than in the vine monoculture, respectively. The grape phylloxera population number on the grape roots decreased each year, and the vine trees gradually renewed upon continuous intercropping with tobacco over three years. These results confirmed that intercropping grapes with tobacco can effectively control grape phylloxera in an infested vineyard. The results also indicated that additional crops could be intercropped with grapes and are effective against grape phylloxera, which should be explored as an integrated approach for controlling the pest.
基金The National Natural Science Foundation of China(No.51308227)the Fundamental Research Funds for the Central Universities(No.201522087)+1 种基金the Science and Technology Planning Project of Guangdong Province(No.2016A030305001)the Project of Department of Communications of Guangdong Province(No.2015-02-070)
文摘A perimeter traffic signal control strategy is proposed based on the macroscopic fundamental diagram theory(MFD)to solve the signal control problem in oversaturated states.First,the MFD of a specific regional network can be derived using VSS IM simulation software.Secondly,the maximum number of cumulative vehicles that the network can accommodate is determined based on the MFD.Then,through monitoring the influx flow,the number of vehicles existing in and exiting from the network,a perimeter traffic control model is proposed to optimize the signal timing of the boundary intersections.Finally,a virtual network simulation model is established and three different kinds o f traffic demand are loaded into the network.Simulation results show that a fer the strategy implementation,the number o f vehicles accumulating in the network can be kept near the optimal value,while the number o f both entering and exiting vehicles increases significantly and the road network can be maintained at a large capacity.Simultaneously,the queue length at the approach of the border intersections is reasonably controlled and vehicles entering and exiting the network can maintain a more efficient and stable speed.The network performance indices such as the average traffic delay and average number of stops can be improved to a certain degree,thus verifying the effectiveness and feasibility of the perimeter control strategy.
