(3)This paper builds the WECC system dynamics model of river, comprehensively considering many factors including economic development, population growth, environmental capacity of pollutant, the river ecological and environmental water demand, the control measures of water pollution and the protective plan of water environment, simulating the indexes in WECC index system.
The effect of food and initial population density on the population growth of Brachionus plicatilis by the method of orthogonal design as water temperature was at (17.8±1.3) ℃ and (23.3±1.9) ℃ were studied separately.
In this paper,a new self adaptive model for population growth,i. e. S= exp (α ln 2(1+ce -rt )+β ln (1+ce -rt )+γ) was established,which combined Logistic,Smith,Gompertz,Cui Lawson,Zhang Logistic and Liu Logistic models.
Indices of population trend (Y) of this species within the range of temperatures (X) studied can be expressed as follows:Y =-2530.285 + 282.1893X - 6.2407X2It is calculated with this equation that the favourable temperature for the population growth is 22.6℃, at which the number of the armyworm will increase about 660 times after one generation cycle.
Rotifer can survive at pH 3. 5 ~ 11. 5, but the optimum pH for population growth is 8. 5. where the rotifer shows a maximum reproductive sped. and the absolute egg density is the highest (132 cells' ml-1 ).
The results indicate that the population growth was greatly affected by temperature and the Q 10 being 2.37 in the range from 8 to 33℃, while the population growth and the morphology of this specie were not significantly affected by the salinity in the range from 10 to 60‰.
Analysis of data showed that the ammonia accumulation was higher than that of the control during the equilibrium stage of ciliate population growth,and was significantly lower than in the control during the decaying stage either in Euplotes treatments with a range of 0 01-0 2 g/L glucose concentrations or in the Uronema treatments with a range of 0 05-0 2 g/L glucose concentrations.
Compared with other models, Logistic model has solved the simulated problem in the process of population growth when the growth rate changes, but it lacks the calculating function in the area of negative population growth.
A new class of competition models in which the population growth coefficients are represented by periodic delta-functions is designed.
Analysis of the available field and published data indicates a two-stage pattern of the population growth phase and a synchronous transition of wolf populations to this phase.
Selenium in concentrations of 0.01 and 0.5 mg/liter stimulated cell population growth, while the number of ultrastructural alterations was the same as in the control cells.
At a selenium concentrations of 1 mg/liter, cell population growth slightly decreased by the end of the experiment, and there was some increase in the number of cells with damaged organoids and in the number of completely destroyed cells.
salina, suppressing cell population growth and promoting extensive destructive changes.