Elements （vanadium and zinc） were determined in the two most abundant species of shell mollusks （Unio tigridis and Fiviparous bengalensis） and the water where they live in five stations in the Iraqi marshes. The s...Elements （vanadium and zinc） were determined in the two most abundant species of shell mollusks （Unio tigridis and Fiviparous bengalensis） and the water where they live in five stations in the Iraqi marshes. The study of concentrations elements was a target organ for aquatic environmental. Comparison between the mean concentrations of the elements in the water concentration levels of all studied elements was the highest with the mollusks. The results show that the station 5 is where the highest concentrations are found in water and in the two species. There is a significant correlation （P = 0.224） for concentrations of vanadium and P = 0.735 for zinc in two species of mollusks relative to their concentrations in surface water. All significant differences were accepted at a level of P 〈 0.05. The potential uptake of elements including V and Zn, as Viviparous bengalensi 〉 Unio tigridis, The mechanism for elements uptake determined by water for organisms confined to the contaminated areas seemed to be largely independent of species, mollusks demonstrated a significant positive relationship with water. These results have important implications for the utility of marshes biota as subjects for elements monitoring program.展开更多
Considering repulsive interspecies interactions,we study the dynamical properties of bright-bright solitons in two species Bose-Einstein condensates by using a variational approach combined with numerical simulation.I...Considering repulsive interspecies interactions,we study the dynamical properties of bright-bright solitons in two species Bose-Einstein condensates by using a variational approach combined with numerical simulation.It is shown that the interactions between bright-bright solitons vary from repulsive to attractive interactions with the increasing their separating distances,and at equilibrium position the bright-bright solitons are localized.Interestingly,a transition from reflection-to transmission-collision is firstly observed,different from previous results of only reflection collision appearing there.These results will be helpful for the experimental manipulating such solitons.展开更多
We propose an efficient numerical method for two population models, based on the nonstandard finite difference （NSFD） schemes and composition methods with complex time steps. The NSFD scheme is able to give positive...We propose an efficient numerical method for two population models, based on the nonstandard finite difference （NSFD） schemes and composition methods with complex time steps. The NSFD scheme is able to give positive numerical solutions that satisfy the conservation law, which is a key property for biological population models. The accuracy is improved by using the composition methods with complex time steps. Numerical tests on the plankton nutrient model and whooping cough model are presented to show the efficiency and advantage of the proposed numerical method.展开更多
A stochastic two-species Schoener＇s competitive model is proposed and investigated. Sufficient conditions for the existence of global positive solutions, boundedness~ uniform continuity, global attractivity stochasti...A stochastic two-species Schoener＇s competitive model is proposed and investigated. Sufficient conditions for the existence of global positive solutions, boundedness~ uniform continuity, global attractivity stochastic permanence and extinction are obtained. More- over, the upper-growth rate and the average in time of the sample paths of solutions are also estimated. Finally, some figures are introduced to illustrate the main results.展开更多
文摘Elements （vanadium and zinc） were determined in the two most abundant species of shell mollusks （Unio tigridis and Fiviparous bengalensis） and the water where they live in five stations in the Iraqi marshes. The study of concentrations elements was a target organ for aquatic environmental. Comparison between the mean concentrations of the elements in the water concentration levels of all studied elements was the highest with the mollusks. The results show that the station 5 is where the highest concentrations are found in water and in the two species. There is a significant correlation （P = 0.224） for concentrations of vanadium and P = 0.735 for zinc in two species of mollusks relative to their concentrations in surface water. All significant differences were accepted at a level of P 〈 0.05. The potential uptake of elements including V and Zn, as Viviparous bengalensi 〉 Unio tigridis, The mechanism for elements uptake determined by water for organisms confined to the contaminated areas seemed to be largely independent of species, mollusks demonstrated a significant positive relationship with water. These results have important implications for the utility of marshes biota as subjects for elements monitoring program.
基金Supported by National Natural Science Foundation of China under Grant Nos.51032002 and 11074212Foundation for the Author of National Excellent Doctoral Dissertation of China under Grant No.200726+1 种基金the Key Project of the National HighTechnology Research and Development Program ("863" Program) of China under Grant No.2011AA050526Hunan Provincial Innovation Foundation for Postgraduate under Grant No.CX2010B254
文摘Considering repulsive interspecies interactions,we study the dynamical properties of bright-bright solitons in two species Bose-Einstein condensates by using a variational approach combined with numerical simulation.It is shown that the interactions between bright-bright solitons vary from repulsive to attractive interactions with the increasing their separating distances,and at equilibrium position the bright-bright solitons are localized.Interestingly,a transition from reflection-to transmission-collision is firstly observed,different from previous results of only reflection collision appearing there.These results will be helpful for the experimental manipulating such solitons.
文摘We propose an efficient numerical method for two population models, based on the nonstandard finite difference （NSFD） schemes and composition methods with complex time steps. The NSFD scheme is able to give positive numerical solutions that satisfy the conservation law, which is a key property for biological population models. The accuracy is improved by using the composition methods with complex time steps. Numerical tests on the plankton nutrient model and whooping cough model are presented to show the efficiency and advantage of the proposed numerical method.
基金This work was supported by the National Natural Science Foundation of P. R. China （No. 11171081, 11171056）, the Natural Scientific Research Innovation Foundation in Harbin Institute of Technology （No. HIT.NSRIF.2011094）, and the Scientific Research Foundation of Harbin Institute of Technology at Weihai （No. HIT （WH） ZB201103）.
文摘A stochastic two-species Schoener＇s competitive model is proposed and investigated. Sufficient conditions for the existence of global positive solutions, boundedness~ uniform continuity, global attractivity stochastic permanence and extinction are obtained. More- over, the upper-growth rate and the average in time of the sample paths of solutions are also estimated. Finally, some figures are introduced to illustrate the main results.
