We study numerically and analytically a stochastic group selection model in which a population of asexually reproducing individuals, each of which can be either altruist or non-altruist, is subdivided into M reproductively isolated groups (demes) of size N . The cost associated with being altruistic is modelled by assigning the fitness 1 − τ , with τ ∈ [0, 1], to the altruists and the fitness 1...

Enthalpy (fuel mass fraction and/or temperature) fluctuations in the oncoming mixture are known to have important impacts on premixed combustion and in particular on combustion instability. Theoretical modeling has primarily been following an empirical approach. In Part I of the present study, an asymptotically reduced first-principle theory was derived from the reactive Navier-Stokes equations...

This paper demontrates that the conditions for the existence of a dissipation-induced heteroclinic orbit between the inverted and noninverted states of a tippe top are determined by a complex version of the equations for a simple harmonic oscillator: the modified Maxwell– Bloch equations. A standard linear analysis reveals that the modified Maxwell–Bloch equations describe the spectral instabil...

A general class of linear advective PDEs, whose leading order term is of viscous dissipative type, is considered. It is proved that beyond the limit of the essential spectrum of the underlying inviscid operator, the eigenvalues of the viscous operator, in the limit of vanishing viscosity, converge precisely to those of the inviscid operator. The general class of PDEs includes the equations of i...

In this paper we propose a positive linear control law for the stabilization of positive equilibria in predator-prey systems. This problem is motivated by the introduction, which is by essence positive, of predators in biological control applications, to prevent excessive levels of prey (pests). We build a linear controller that we saturate at zero and prove, under some conditions, the global a...

The chiral symmetry breaking properties of the Tayler instability are discussed. Effective amplitude equations are determined in one case. This model has three free parameters that are determined numerically. Comparison with chiral symmetry breaking in biochemistry is made.

This study constructs a nonlinear dynamic model of articulated vehicles and hydraulic steering system. The equations state required for vehicle dynamics models, stability analysis corresponding eigenvalue are obtained by constructing Newtonian mechanical equilibrium equations. objective subjective causes the snake oscillation relevant indicators evaluating instability analysed using several par...

Undular bores, also termed dispersive shock waves, generated by an initial discontinuity in height as governed two forms of the Boussinesq system weakly nonlinear shallow water wave theory, standard formulation and a Hamiltonian formulation, related Whitham–Boussinesq equations, full equations for gravity surface waves are studied compared. It is found that systems give solutions excellent agre...

We present a theory of resonances for a class of non-autonomous Hamiltonians to treat the structural instability of spatially localized and time-periodic solutions associated with an unperturbed autonomous Hamiltonian. The mechanism of instability is radiative decay, due to resonant coupling of the discrete modes to the continuum modes by the time-dependent perturbation. This results in a slow ...

We present a theory of resonances for a class of nonautonomous Hamiltonians to treat the structural instability of spatially localized and time-periodic solutions associated with an unperturbed autonomous Hamiltonian. The mechanism of instability is radiative decay, due to resonant coupling of the discrete modes to the continuum modes by the time-dependent perturbation. This results in a slow t...