Transition to hexagonal pattern under the variation of intrinsic length scales of a reaction diffusion system

The intrinsic length scales of a reaction diffusion system (Gierer-Meinhardt model)is varied by quasi-statically changing the diffusion constant of the activator and a transition from rolls to hexagon is detected. The transition is hysteretic or first order like. From stability analysis, we also analytically show the possibility of such transitions.Comment: One .tex file and four .ps file

An Alternative Estimation Framework for Firm-Level Capital Investment

This paper derives and implements Tobit estimation frameworks based on the Abel and Eberly (1998) investment model. We find evidence that a model of investment using rates of capacity utilisation is superior to a standard accelerator model. We apply this framework to a cross-section of firms in Poland, Romania and Spain in order to estimate the incidence of financing constraints.

Scaling of internode distances in weighted complex networks

We extend the previously observed scaling equation connecting the internode distances and nodes' degrees onto the case of weighted networks. We show that the scaling takes a similar form in the empirical data obtained from networks characterized by different relations between node's strength and its degree. In the case of explicit equation for s(k) (e.g. linear or scale-free), the new coefficients of scaling equation can be easily obtained. We support our analysis with numerical simulations for Erdos-Renyi random graphs with different weight distributions.Comment: 9 pages, 4 figures, submitted to International Journal of Modern Physics

What is an epitheliome, anyway?

No abstract available

The influence of leaf characteristics on epiphyllic cover : a test of hypotheses with artificial leaves

Studies of epiphyll ecology have been hindered by the biochemical and morphological variability of the leaf substrate. The use of artificial (plastic ribbon tape) leaves solved that problem in a study done at the Braulio Carrillo National Park, Costa Rica. It showed that after nine months of field exposure, relative epiphyll cover was similar in five leaf shapes and two sizes. Driptips do not affect epiphyll cover, which was four times higher under a clearing than in the shaded understory, for all leaf shapes and sizes