Integrable Time-Discretisation of the Ruijsenaars-Schneider Model

An exactly integrable symplectic correspondence is derived which in a continuum limit leads to the equations of motion of the relativistic generalization of the Calogero-Moser system, that was introduced for the first time by Ruijsenaars and Schneider. For the discrete-time model the equations of motion take the form of Bethe Ansatz equations for the inhomogeneous spin-1/2 Heisenberg magnet. We present a Lax pair, the symplectic structure and prove the involutivity of the invariants. Exact solutions are investigated in the rational and hyperbolic (trigonometric) limits of the system that is given in terms of elliptic functions. These solutions are connected with discrete soliton equations. The results obtained allow us to consider the Bethe Ansatz equations as ones giving an integrable symplectic correspondence mixing the parameters of the quantum integrable system and the parameters of the corresponding Bethe wavefunction.Comment: 27 pages, latex, equations.st

Fisheries value chain in Bolivia's Northern Amazon : contributions of native species and an introduced species (paiche – Arapaima gigas)

Resumen en inglés incluidoLos recursos pesqueros de agua dulce de la Amazonía requieren ser estudiados con mayor atención, sobre todo por su valor alimenticio y por su potencial productivo. En Bolivia, las cadenas productivas de pescado han recibido poca atención tanto de los que diseñan las políticas públicas como de los mismos productores, lo cual hace que el sector pesquero no se haya desarrollado con la misma intensidad que otros sectores productivos. La presente investigación, de carácter plenamente participativo con los actores locales, caracteriza y evalúa las actividades pesqueras en el norte amazónico de Bolivia, abriendo así una importante brecha para la investigación - acción y para la definición de políticas de conservación y aprovechamiento sustentable. El estudio identifica los aspectos sociales y económicos de las cadenas productivas tanto de especies nativas como del paiche, especie introducida en la zona, dentro de los cuales se presentan una serie de conflictos como, por ejemplo, los que son el resultado de la falta de definición de los derechos de uso del recurso. Este trabajo contribuye al diseño de estrategias de manejo y conservación de los recursos pesqueros y de los ecosistemas acuáticos en Bolivia

Analysis of the root diameter distribution from time series images of real and simulated Cassava root systems

The data was collected, simulated and analyzed in the framework of the CassavaStore project (a collaboration between IBG-2, Forschungszentrum Jülich, Germany and different institution from Thailand; for details see https://www.international-bioeconomy.org/cassavastore_eng). Aim of this project is to get a better understanding of storage root development in cassava (Manihot esculenta Crantz) in order to optimize cassava growth with respect to variety breeding and growth management. The storage root is one of the main providers of starch in Thailand and therefore of high economic importance. Monitoring the formation of storage roots over time via quantification of the root diameter distribution of excavated root systems was one of the key aspects addressed in this project. To measure the diameters a software was developed that identifies roots in RGB images and analyzes the diameters along each identified root automatically. The published data contains 1) analyzed images from cassava roots that were acquired in a video box; 2) simulated virtual root model images with known root diameter distributions that were used to validate the analysis approach; 3) a description of the data and the folder structure

"Symmetry and Perturbation Theory'', Proceedings of the International Conference SPT2004

This proceedings volume is a collection of papers presented at the International Conference on SPT2004 focusing on symmetry, perturbation theory, and integrability. The book provides an updated overview of the recent developments in the various different fields of nonlinear dynamics, covering both theory and applications. Special emphasis is given to algebraic and geometric integrability, solutions to the N-body problem of the “choreography” type, geometry and symmetry of dynamical systems, integrable evolution equations, various different perturbation theories, and bifurcation analysis. The contributors to this volume include some of the leading scientists in the field, among them: I Anderson, D Bambusi, S Benenti, S Bolotin, M Fels, W Y Hsiang, V Matveev, A V Mikhailov, P J Olver, G Pucacco, G Sartori, M A Teixeira, S Terracini, F Verhulst and I Yehorchenko