A new method to obtain thick domain wall solutions to the coupled Einstein scalar field system is presented. The procedure allows the construction of irregular walls from well known ones, such that the spacetime associated to them are physically different. As consequence of the approach, we obtain two irregular geometries corresponding to thick domain walls with $dS$ expansion and topological double kink embedded in $AdS$ spacetime. In particular, the double brane can be derived from a fake superpotential.Comment: 13 pages, 4 figures, added references, some equations correcte

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As is well known, submerged horizontal cylinders can serve as waveguides for surface water waves. For large values of the wavenumberkin the direction of the cylinders, there is only one trapped wave. We construct asymptotics of these trapped modes and their frequencies ask→∞in the case of one or two submerged cylinders by means of reducing the initial problem to a system of integral equations on the boundaries and then solving them using a technique suggested by Zhevandrov and Merzon (2003).

In this work, we use an analytical approach to study the dynamic consequences of refuge use by the prey in the Rosenzweig-MacArthur predator-prey model with the refuge function proposed by Almanza-Vasquez. We will evaluate the effects with regard to the local stability of equilibrium points in the first quadrant. We show that there is a trend from limit cycles through non-zero stable points.

In this article, a simple expression for the center of mass of a system of material points in a two-dimensional surface of Gaussian constant negative curvature is given. By using the basic techniques of geometry, we obtained an expression in intrinsic coordinates, and we showed how this extends the definition for the Euclidean case. The argument is constructive and serves to define the center of mass of a system of particles on the one-dimensional hyperbolic sphere LR1.