Spontaneous emergence of spatial patterns ina a predator-prey model

We present studies for an individual based model of three interacting populations whose individuals are mobile in a 2D-lattice. We focus on the pattern formation in the spatial distributions of the populations. Also relevant is the relationship between pattern formation and features of the populations' time series. Our model displays travelling waves solutions, clustering and uniform distributions, all related to the parameters values. We also observed that the regeneration rate, the parameter associated to the primary level of trophic chain, the plants, regulated the presence of predators, as well as the type of spatial configuration.Comment: 17 pages and 15 figure

A Grassmann integral equation

The present study introduces and investigates a new type of equation which is called Grassmann integral equation in analogy to integral equations studied in real analysis. A Grassmann integral equation is an equation which involves Grassmann integrations and which is to be obeyed by an unknown function over a (finite-dimensional) Grassmann algebra G_m. A particular type of Grassmann integral equations is explicitly studied for certain low-dimensional Grassmann algebras. The choice of the equation under investigation is motivated by the effective action formalism of (lattice) quantum field theory. In a very general setting, for the Grassmann algebras G_2n, n = 2,3,4, the finite-dimensional analogues of the generating functionals of the Green functions are worked out explicitly by solving a coupled system of nonlinear matrix equations. Finally, by imposing the condition G[{\bar\Psi},{\Psi}] = G_0[{\lambda\bar\Psi}, {\lambda\Psi}] + const., 0<\lambda\in R (\bar\Psi_k, \Psi_k, k=1,...,n, are the generators of the Grassmann algebra G_2n), between the finite-dimensional analogues G_0 and G of the (``classical'') action and effective action functionals, respectively, a special Grassmann integral equation is being established and solved which also is equivalent to a coupled system of nonlinear matrix equations. If \lambda \not= 1, solutions to this Grassmann integral equation exist for n=2 (and consequently, also for any even value of n, specifically, for n=4) but not for n=3. If \lambda=1, the considered Grassmann integral equation has always a solution which corresponds to a Gaussian integral, but remarkably in the case n=4 a further solution is found which corresponds to a non-Gaussian integral. The investigation sheds light on the structures to be met for Grassmann algebras G_2n with arbitrarily chosen n.Comment: 58 pages LaTeX (v2: mainly, minor updates and corrections to the reference section; v3: references [4], [17]-[21], [39], [46], [49]-[54], [61], [64], [139] added

The process of building European university alliances: a rhizomatic analysis of the European Universities Initiative

Drawing upon French philosophy, this study offers a novel empirical and conceptual understanding of the newly launched European Universities Initiative. In 2019, higher education institutions across the European Union created 17 new alliances as part of the first pilot phase of the initiative. This is an experiment in European and global higher education. This paper offers a conceptual contribution to the field of higher education studies, making use of a rhizomatic analysis to explore how university alliances build what the European Commission refers to as the ‘European universities of the future.’ Based on the conceptual reflection and findings from a small-scale empirical study, this paper concludes that the alliances within the European Universities Initiative rely on pre-existing higher education and research partnerships while at the same time experimenting to foster a diversity of institutional forms to achieve the ambitious goal of creating ‘European Universities.

Exploratory study on the behaviour of glass/PDCPD composites

© 2015 International Committee on Composite Materials. All rights reserved. The potential of the tough thermoset polydicyclopentadiene (PDCPD) as a matrix for composite materials was explored in this study. A range of properties was compared for a composite with a PDCPD formulation matrix and an equivalent epoxy composite. The PDCPD composite showed higher interlaminar fracture toughness and reduced damage development during tensile loading. Improved fatigue life and higher compressive strength were observed. Impact damage was greatly reduced and substantial improvement in compression after impact strength was noted. Based on the obtained results, the PDCPD formulation used in this work can be considered an interesting alternative for brittle thermosets.status: publishe

Effets de la perfusion d'agonistes bêta-, bêta2- ou bêta3-adrégéniques ou d'adrenaline sur la lipolyse in situ du tissu adipeux sous-cutané ovin

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