This paper studies an extension of the Mankiw-Romer-Weil growth model in discrete time by departing from the standard assumption of constant population growth rate. More concretely, this rate is assumed to be decreasing over time and a general population growth law verifying this characteristic is introduced. In this setup, the model can be represented by a three dimensional dynamical system wh...

In many biologically relevant situations, cells of a clonal population show a heterogeneous response upon a common stimulus. The computational analysis of such situations requires the study of cell-cell variability and modeling of heterogeneous cell populations. In this work, we consider populations where the behavior of every single cell can be described by a system of ordinary differential eq...

the relationship between initial population density of rice white tip nematode (aphelenchoides besseyi) and yield was examined on oryzae sativa cv. alikazemi. experiments were conducted in greenhouse, micro-plot and field conditions. seinhorst’s model was used to describe the relationship between nematode population density and crop yield. the parameters of the model, minimum yield (m), constan...

We put forward a framework for cosmology that combines the string landscape with no boundary initial conditions. In this framework, amplitudes for alternative histories for the universe are calculated with final boundary conditions only. This leads to a top down approach to cosmology, in which the histories of the universe depend on the precise question asked. We study the observational consequ...

We study the formation and evolution of Brightest Cluster Galaxies starting from a z = 2 population of quiescent ellipticals and following them to z = 0. To this end, we use a suite of nine high-resolution dark matter-only simulations of galaxy clusters in a ΛCDM universe. We develop a scheme in which simulation particles are weighted to generate realistic and dynamically stable stellar density...

I n "Cultural Transmission, Disproportionate Prior Expos ure, and th e Evolu ti on of Cooperation," Mark (2002) claims to have "condueted a formal theoretical analysis that isolated the logic of cultural transmission (to] reveal an evolutionary force toward cooperation under conditions previously thought to make the evolution of cooperation impossible" (p. 324). The most striking aspect of Mark...