Modified Korteweg-de Vries Hierachies in Multiple-Times Variables and the Solutions of Modified Boussinesq Equations

We study solitary-wave and kink-wave solutions of a modified Boussinesq equation through a multiple-time reductive perturbation method. We use appropriated modified Korteweg-de Vries hierarchies to eliminate secular producing terms in each order of the perturbative scheme. We show that the multiple-time variables needed to obtain a regular perturbative series are completely determined by the associated linear theory in the case of a solitary-wave solution, but requires the knowledge of each order of the perturbative series in the case of a kink-wave solution. These appropriate multiple-time variables allow us to show that the solitary-wave as well as the kink-wave solutions of the modified Botussinesq equation are actually respectively a solitary-wave and a kink-wave satisfying all the equations of suitable modified Korteweg-de Vries hierarchies.Comment: RevTex file, submitted to Proc. Roy. Soc. London

Sandpile model on an optimized scale-free network on Euclidean space

Deterministic sandpile models are studied on a cost optimized Barab\'asi-Albert (BA) scale-free network whose nodes are the sites of a square lattice. For the optimized BA network, the sandpile model has the same critical behaviour as the BTW sandpile, whereas for the un-optimized BA network the critical behaviour is mean-field like.Comment: Five pages, four figure

University libraries as active agents for change. The BitViews Project : how University librarians can turn all journals green and clear the path to open science

There can be no open science without Open Access (OA). This paper is a call to arms to individual University librarians to make a decisive move towards open access. The short-term objective of OA is defined as the immediate, cost-free, online access to the content of all peer reviewed scientific, medical, and scholarly articles. This amounts to unrestricted access to the author’s approved manuscripts (AAMs) deposited in institutional and other repositories. Even in the current academic publishing ecosystem, largely directed and managed by a few oligopolistic commercial publishers, 80% of peer reviewed articles can be deposited as AAMs, but only a small minority of researchers choose to do so. The reason for this failure is that currently there are no individual incentives for researchers to promote their AAMs, as the main currency of academic recognition and esteem (the citation count) resides with published articles. The author has described elsewhere how an open-source blockchain application (BitViews) can collect, validate, and disseminate at minimal cost online usage data of all AAMs available on institutional repositories. The resulting public ledger of usage data can be used to arrange discipline-specific non-citation research impact measures thereby providing the incentive for more authors to deposit their AAMs in a virtuous circle. The green OA thus achieved allows researchers in the global South to enter scholarly communication not only as consumers but also as producers of peer-reviewed knowledge. BitViews Project allows individual university libraries to be catalysts for change. The paper explains how a novel application of game theory (conditional crowdfunding) will empower individual libraries to spread the relatively miniscule costs of setting up BitViews using a two-stage mechanism that minimises free-riding and offers a no-risk opportunity to libraries to deploy their institutional repositories not just as stores of information, but as active tools to achieve open access.Publisher PD

Chaos in Sandpile Models

We have investigated the "weak chaos" exponent to see if it can be considered as a classification parameter of different sandpile models. Simulation results show that "weak chaos" exponent may be one of the characteristic exponents of the attractor of \textit{deterministic} models. We have shown that the (abelian) BTW sandpile model and the (non abelian) Zhang model posses different "weak chaos" exponents, so they may belong to different universality classes. We have also shown that \textit{stochasticity} destroys "weak chaos" exponents' effectiveness so it slows down the divergence of nearby configurations. Finally we show that getting off the critical point destroys this behavior of deterministic models.Comment: 5 pages, 6 figure

Boussinesq Solitary-Wave as a Multiple-Time Solution of the Korteweg-de Vries Hierarchy

We study the Boussinesq equation from the point of view of a multiple-time reductive perturbation method. As a consequence of the elimination of the secular producing terms through the use of the Korteweg--de Vries hierarchy, we show that the solitary--wave of the Boussinesq equation is a solitary--wave satisfying simultaneously all equations of the Korteweg--de Vries hierarchy, each one in an appropriate slow time variable.Comment: 12 pages, RevTex (to appear in J. Math Phys.

Sandpile Model with Activity Inhibition

A new sandpile model is studied in which bonds of the system are inhibited for activity after a certain number of transmission of grains. This condition impels an unstable sand column to distribute grains only to those neighbours which have toppled less than m times. In this non-Abelian model grains effectively move faster than the ordinary diffusion (super-diffusion). A novel system size dependent cross-over from Abelian sandpile behaviour to a new critical behaviour is observed for all values of the parameter m.Comment: 11 pages, RevTex, 5 Postscript figure