Université de Fribourg

The feasibility of equilibria in large ecosystems: A primary but neglected concept in the complexity-stability debate

Dougoud, Michaël ; Vinckenbosch, Laura ; Rohr, Rudolf P. ; Bersier, Louis-Félix ; Mazza, Christian

In: PLOS Computational Biology, 2018, vol. 14, no. 2, p. e1005988

The consensus that complexity begets stability in ecosystems was challenged in the seventies, a result recently extended to ecologically-inspired networks. The approaches assume the existence of a feasible equilibrium, i.e. with positive abundances. However, this key assumption has not been tested. We provide analytical results complemented by simulations which show that equilibrium...

Université de Fribourg

The effect of gap junctional coupling on the spatiotemporal patterns of Ca2+ signals and the harmonization of Ca2+-related cellular responses

Dougoud, Michaël ; Vinckenbosch, Laura ; Mazza, Christian ; Schwaller, Beat ; Peczey, László

In: PLOS Computational Biology, 2016, vol. 12, no. 12, p. e1005295

The calcium ion (Ca²⁺), a universal signaling molecule, is widely recognized to play a fundamental role in the regulation of various biological processes. Agonist–evoked Ca²⁺ signals often manifest as rhythmic changes in the cytosolic free Ca²⁺ concentration (ccyt) called Ca²⁺ oscillations. Stimuli intensity was found to be proportional to the oscillation frequency...

Université de Fribourg

Monte Carlo methods for light propagation in biological tissues

Vinckenbosch, Laura ; Lacaux, Céline ; Tindel, Samy ; Thomassin, Magalie ; Obara, Tiphaine

In: Mathematical Biosciences, 2015, vol. 269, p. 48–60

Light propagation in turbid media is driven by the equation of radiative transfer. We give a formal probabilistic representation of its solution in the framework of biological tissues and we implement algorithms based on Monte Carlo methods in order to estimate the quantity of light that is received by a homogeneous tissue when emitted by an optic fiber. A variance reduction method is studied and...