The food chain refers to a natural system by which energy is transmitted from one organism to another. In fact, a food chain consists of producers, consumers and decomposition. Presence of complex food web increase the stability of the ecosystem. Classical food chain theory arises from Lotka-Volterra model. In the present paper, the dynamics behavior of three level food chain is studied. A syst...

In this study, considering the importance of how to exploit renewable natural resources, we analyzea shing model with nonlinear harvesting function in which the players at the equilibrium pointdo a static game with complete information that, according to the calculations, will cause a wasteof energy for both players and so the selection of cooperative strategies along with the...

purpose: to evaluate the effect of age, sex, type of surgery, extent of retinal detachment (rd), vitreous incarceration in wound, and myopic degeneration on the rate of retinal redetachment following rd surgery using eternal weibull regression analysis. methods: we performed a survival analysis on a multi-center randomized controlled trial conducted on patients with pseudophakic or aphakic rd t...

The solubility of naproxen in binary mixtures of polyethylene glycol 200 (PEG 200) + water at the temperature range from 298.0 K to 318.0 K were reported. The combinations of Jouyban-Acree model + van’t Hoff and Jouyban-Acree model + partial solubility parameters were used to predict the solubility of naproxen in PEG 200 + water mixtures at different temperatures. Combination of Jouyban-Acree m...

On the basis of the continuity equation and the Bernoulli equation in the steady form, a differential equation is developed to evaluate the successive water levels within compartments of an upright perforated wave absorber. Then the initial and boundary conditions are introduced and the differential equation is solved as an initial value problem. Finally the reflection coefficient from the wave...

We consider a mathematical model of epidemic spread  in which the  population  is partitioned  into five compartments of susceptible S(t), Infected I(t), Removed R(t), Prevented U(t) and the Controlled W(t). We assume each of the compartments comprises of cohorts of individuals which are  identical with respect to the disease status. We derive five systems of equations to represent each of the ...