Abstract. In this paper, a predator-prey system with Holling type II functional response and stage structure is investigated. By analyzing the corresponding characteristic equations, the local stability of each of feasible equilibria of the system is studied. The existence of the orbitally asymptotically stable periodic solution is established. By using suitable Lyapunov functions and the LaSal...

In this paper, we present two iterative algorithms for approximating the absorption spectrum of molecules within the linear response of time-dependent density functional theory (TDDFT) framework. These methods do not attempt to compute eigenvalues or eigenvectors of the linear response matrix. They are designed to approximate the absorption spectrum as a function directly. They take advantage o...

protein hydro-lysate was prepared from gold striped sardine (sardinella gibossa) by papain. hydrolysis conditions (time, temperature, and enzyme activity) were optimized by response surface methodology (rsm) using a factorial design and anti-oxidative activity was the dependent variable. results of the total determination coefficient, adjusted r2 and predicted r2 indicating the validity of pred...

Within the adiabatic approximation, time-dependent density functional theory yields only single excitations. Near states of double excitation character, the exact exchange-correlation kernel has a strong dependence on frequency. We derive the exact frequency-dependent kernel when a double excitation mixes with a single excitation, well separated from the other excitations, in the limit that the...

We explore the complex dynamical behavior of two simple predator-prey models of biological coevolution that on the ecological level account for interspecific and intraspecific competition, as well as adaptive foraging behavior. The underlying individual-based population dynamics are based on a ratio-dependent functional response [W.M. Getz, J. theor. Biol. 108, 623 (1984)]. Analytical results f...

Background: Stimulants addition and abuse can cause some functional and morphological changes in the normal function of glands and hormones. Methamphetamine as an addictive stimulant drug affects the Hypothalamic-pituitary-adrenal (HPA) axis and consequently makes some changes in the psychological state of the drug users. The present study aims to examine the relationship between plasma levels ...

We present a linear-response approach for time-dependent density-functional theories using time-adiabatic functionals. The resulting theory can be performed both in the time and in the frequency domain. The derivation considers an impulsive perturbation after which the Kohn-Sham orbitals develop in time autonomously. The equation describing the evolution is not strictly linear in the wave funct...

Time-dependent density matrix functional theory can be formulated in terms of coupled-perturbed response equations, in which a coupling matrix K(omega) features, analogous to the well-known time-dependent density functional theory (TDDFT) case. An adiabatic approximation is needed to solve these equations, but the adiabatic approximation is much more critical since there is not a good "zero ord...

In this paper we propose an extension of the self-consistent charge-density-functional tight-binding ~SCCDFTB! method @M. Elstner et al., Phys. Rev. B 58, 7260 ~1998!#, which allows the calculation of the optical properties of finite systems within time-dependent density-functional response theory ~TD-DFRT!. For a test set of small organic molecules low-lying singlet excitation energies are com...

Recent development in particle-particle random phase approximation (pp-RPA) broadens the perspective on ground state correlation energies [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013), Y. Yang, H. van Aggelen, S. N. Steinmann, D. Peng, and W. Yang, J. Chem. Phys. 139, 174110 (2013); D. Peng, S. N. Steinmann, H. van Aggelen, and W. Yang, J. Chem. Phys. 139, 104112 (2013)]...