Plant invasion refers to the phenomenon that some plants grow too fast due to they are far away from the original living environment or predators, affecting the local environment. With the development of tourism and t...Plant invasion refers to the phenomenon that some plants grow too fast due to they are far away from the original living environment or predators, affecting the local environment. With the development of tourism and trade, the harm caused by invasive plants will be more and more serious. Therefore, it is necessary to ex- plore an effective method for controlling plant invasion through qualitative and quan- titative research. In this paper, the models were established for the early and late harmful plant invasion control. The huge computation was completed by the com- puter programming to obtain the optimal solutions of the models. The real meaning of the optimal solution was further discussed. Through numerical simulations and discussion, it could be concluded that the quantitative research on the invasive plant control had a certain application value.展开更多
Field infiltration measurement is often a tedious task thus can be easily estimated from proposed infiltration models. The Horton equation is one of the popular models used in the characterization of field infiltratio...Field infiltration measurement is often a tedious task thus can be easily estimated from proposed infiltration models. The Horton equation is one of the popular models used in the characterization of field infiltration. In this study, the least square curve firing technique was employed to estimate the model parameters from fifteen field measured data and gave resultant mean regression coefficients （R2） value of 0.811. Furthermore, plotting the measured against the calculated infiltration rate for the first six （6） measurement points yielded R2 values close to unity in the regression curve indicating a marked relationship between the two. This indicates that the Horton infiltration model can be applied to estimate infiltration characteristics of soils in Samaru, Northern Guinea Savanna of Nigeria.展开更多
Ten runoff plots with different planting patterns were established for experimental observation in Yangjichong small watershed of Longli County in Karst region of Guizhou Province. Results show that under the same rai...Ten runoff plots with different planting patterns were established for experimental observation in Yangjichong small watershed of Longli County in Karst region of Guizhou Province. Results show that under the same rainfall condition, shrub land, natural grassland and abandoned land presented the best function of soil and water conservation. The function of soil and water conservation was poor for arbor planting pattern, because the shrub layer, herb layer and forest floor were not formed. Because of no-tillage, surface crust and other effects, the function of soil and water conservation in slope farmland was better than that in runoffplots with arbor planting pattern.展开更多
Prophylactic DNA vaccines against the influenza virus are promising alternatives to conventional vaccines. In this study, we generated two candidate gene-based influenza vaccines encoding either the seasonal or pandem...Prophylactic DNA vaccines against the influenza virus are promising alternatives to conventional vaccines. In this study, we generated two candidate gene-based influenza vaccines encoding either the seasonal or pandemic hemagglutinin antigen （HA） from the strains A/New Caledonia/20/99 （HIN1） （pV1AS） and A/Califorrtia/04/2009 （H1N1） （pVEH1）, respectively. After verifying antigen expression, the immunogenicity of the vaccines delivered intramuscularly with electroporation was tested in a mouse model. Sera of immunized animals were tested in hemagglutination inhibition assays and by ELISA for the presence of HA-specific antibodies. HA-specific T-cells were also measured in IFN-γ ELISpot assays. The protective efficacy of the candidate influenza vaccines was evaluated by measuring mortality rates and body weight after a challenge with 100 LD50 of mouse-adapted A/New Caledonia/20/99 （H1N1）. Mice immunized with either one of the two vaccines showed significantly higher T cell and humoral immune responses （P〈0.05） than the pVAX1 control group. Additionally, the pV1A5 vaccine effec- tively protected the mice against a lethal homologous mouse-adapted virus challenge with a survival rate of 100% compared with a 40% survival rate in the pVEH1 vaccinated group （P〈0.05）. Our study indicates that the seasonal influenza DNA vac- cine completely protects against the homologous A/New Caledonia/20/99 virus （H1N1）, while the pandemic influenza DNA vaccine only partially protects against this virus.展开更多
文摘Plant invasion refers to the phenomenon that some plants grow too fast due to they are far away from the original living environment or predators, affecting the local environment. With the development of tourism and trade, the harm caused by invasive plants will be more and more serious. Therefore, it is necessary to ex- plore an effective method for controlling plant invasion through qualitative and quan- titative research. In this paper, the models were established for the early and late harmful plant invasion control. The huge computation was completed by the com- puter programming to obtain the optimal solutions of the models. The real meaning of the optimal solution was further discussed. Through numerical simulations and discussion, it could be concluded that the quantitative research on the invasive plant control had a certain application value.
文摘Field infiltration measurement is often a tedious task thus can be easily estimated from proposed infiltration models. The Horton equation is one of the popular models used in the characterization of field infiltration. In this study, the least square curve firing technique was employed to estimate the model parameters from fifteen field measured data and gave resultant mean regression coefficients （R2） value of 0.811. Furthermore, plotting the measured against the calculated infiltration rate for the first six （6） measurement points yielded R2 values close to unity in the regression curve indicating a marked relationship between the two. This indicates that the Horton infiltration model can be applied to estimate infiltration characteristics of soils in Samaru, Northern Guinea Savanna of Nigeria.
文摘Ten runoff plots with different planting patterns were established for experimental observation in Yangjichong small watershed of Longli County in Karst region of Guizhou Province. Results show that under the same rainfall condition, shrub land, natural grassland and abandoned land presented the best function of soil and water conservation. The function of soil and water conservation was poor for arbor planting pattern, because the shrub layer, herb layer and forest floor were not formed. Because of no-tillage, surface crust and other effects, the function of soil and water conservation in slope farmland was better than that in runoffplots with arbor planting pattern.
基金supported by the National High Technology Research and Development Program of China(Grant No.2006AA10A205)the National Key Technology Research and Development Program(Grant No. 2006BAD06A05)the National Key Program for Infectious Diseases of China(Grant No.2009ZX10004-103)
文摘Prophylactic DNA vaccines against the influenza virus are promising alternatives to conventional vaccines. In this study, we generated two candidate gene-based influenza vaccines encoding either the seasonal or pandemic hemagglutinin antigen （HA） from the strains A/New Caledonia/20/99 （HIN1） （pV1AS） and A/Califorrtia/04/2009 （H1N1） （pVEH1）, respectively. After verifying antigen expression, the immunogenicity of the vaccines delivered intramuscularly with electroporation was tested in a mouse model. Sera of immunized animals were tested in hemagglutination inhibition assays and by ELISA for the presence of HA-specific antibodies. HA-specific T-cells were also measured in IFN-γ ELISpot assays. The protective efficacy of the candidate influenza vaccines was evaluated by measuring mortality rates and body weight after a challenge with 100 LD50 of mouse-adapted A/New Caledonia/20/99 （H1N1）. Mice immunized with either one of the two vaccines showed significantly higher T cell and humoral immune responses （P〈0.05） than the pVAX1 control group. Additionally, the pV1A5 vaccine effec- tively protected the mice against a lethal homologous mouse-adapted virus challenge with a survival rate of 100% compared with a 40% survival rate in the pVEH1 vaccinated group （P〈0.05）. Our study indicates that the seasonal influenza DNA vac- cine completely protects against the homologous A/New Caledonia/20/99 virus （H1N1）, while the pandemic influenza DNA vaccine only partially protects against this virus.
