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Consortium of Swiss Academic Libraries

Invariant measures of homeomorphisms and applications to the stability of an hyperbolic PDE

Aassila, Mohammed

In: Bulletin of the Brazilian Mathematical Society, New Series, 2004, vol. 35, no. 1, p. 83-122

Université de Fribourg

Existence, uniqueness and stability analysis of allelopathic stimulatory phytoplankton model

Abbas, Syed ; Banerjee, Malay ; Hungerbühler, Norbert

In: Journal of Mathematical Analysis and Applications, 2010, p. -

In this paper we consider the two species competitive delay plankton allelopathy stimulatory model system. We show the existence and uniqueness of the solution of the deterministic model. Moreover, we study the persistence of the model and the stability properties of its equilibrium points. We illustrate the theoretical results by some numerical simulations.

Université de Fribourg

The linear barycentric rational method for a class of delay Volterra integro-differential equations

Abdi, Ali ; Berrut, Jean-Paul ; Hosseini, Seyyed Ahmad

In: Journal of Scientific Computing, 2018, vol. 75, no. 3, p. 1757-1775

A method for solving delay Volterra integro-differential equations is introduced. It is based on two applications of linear barycentric rational interpolation, barycentric rational quadrature and barycentric rational finite differences. Its zero–stability and convergence are studied. Numerical tests demonstrate the excellent agreement of our implementation with the predicted convergence...

Université de Fribourg

Nondiffusive fluxes in a Brownian system with Lorentz force

Abdoli, I. ; Vuijk, H. D. ; Sommer, J. U. ; Brader, Joseph M. ; Sharma, Abhinav

In: Physical Review E, 2020, vol. 101, no. 1, p. 012120

The Fokker-Planck equation provides a complete statistical description of a particle undergoing random motion in a solvent. In the presence of Lorentz force due to an external magnetic field, the Fokker-Planck equation picks up a tensorial coefficient, which reflects the anisotropy of the particle's motion. This tensor, however, cannot be interpreted as a diffusion tensor; there are...

Université de Fribourg

Correlations in multithermostat Brownian systems with Lorentz force

Abdoli, Iman ; Kalz, Erik ; Vuijk, Hidde D. ; Wittmann, René ; Sommer, Jens-Uwe ; Brader, Joseph M. ; Sharma, Abhinav

In: New Journal of Physics, 2020, vol. 22, no. 9, p. 093057

We study the motion of a Brownian particle subjected to Lorentz force due to an external magnetic field. Each spatial degree of freedom of the particle is coupled to a different thermostat. We show that the magnetic field results in correlation between different velocity components in the stationary state. Integrating the velocity autocorrelation matrix, we obtain the diffusion matrix that...

Université de Fribourg

3-Mercaptopyruvate sulfurtransferase supports endothelial cell angiogenesis and bioenergetics

Abdollahi Govar, Armita ; Törő, Gábor ; Szaniszlo, Peter ; Pavlidou, Athanasia ; Bibli, Sofia‐Iris ; Thanki, Ketan ; Resto, Vicente A. ; Chao, Celia ; Hellmich, Mark R. ; Szabo, Csaba ; Papapetropoulos, Andreas ; Módis, Katalin

In: British Journal of Pharmacology, 2020, vol. 177, no. 4, p. 866–883

During angiogenesis, quiescent endothelial cells (ECs) are activated by various stimuli to form new blood vessels from pre‐existing ones in physiological and pathological conditions. Many research groups have shown that hydrogen sulfide (H2S), the newest member of the gasotransmitter family, acts as a proangiogenic factor. To date, very little is known about the regulatory role of...

Université de Fribourg

Carbon‐assisted stable silver nanostructures

Abdollahi, S. Narjes ; Ochoa Martínez, Efraín ; Kilchoer, Cédric ; Kremer, Geoffroy ; Jaouen, Thomas ; Aebi, Philipp ; Hellmann, Tim ; Mayer, Thomas ; Gu, Yibei ; Wiesner, Ulrich B. ; Steiner, Ullrich ; Wilts, Bodo D. ; Gunkel, Ilja

In: Advanced Materials Interfaces, 2020, vol. 7, no. 23, p. 2001227

Nanostructured silver stands out among other plasmonic materials because its optical losses are the lowest of all metals. However, nanostructured silver rapidly degrades under ambient conditions, preventing its direct use in most plasmonic applications. Here, a facile and robust method for the preparation of highly stable nanostructured silver morphologies is introduced. 3D nanostructured...

Université de Fribourg

Seismotectonic analysis around the Mont Terri rock laboratory (Switzerland): a pilot study

Abednego, Martinus ; Blascheck, Patrick ; Schefer, Senecio ; Nussbaum, Christophe ; Joswig, Manfred ; Bossart, Paul ; Mosar, Jon

In: Swiss Journal of Geosciences, 2017, vol. 110, no. 1, p. 233–251

For this pilot study we used recorded seismic events from the SED permanent network and data from a dedicated SNS network to improve the seismotectonic understanding of very weak seismicity in the vicinity of the Mont Terri underground laboratory. We combined field data on faults with microseismic events and modelling of stress and focal mechanisms. Eighty-six events with very low magnitudes...

Université de Fribourg

Magnetic-field uniformity in neutron electric-dipole-moment experiments

Abel, C. ; Ayres, N. J. ; Baker, T. ; Ban, G. ; Bison, G. ; Bodek, K. ; Bondar, V. ; Crawford, C. B. ; Chiu, P.-J. ; Chanel, E. ; Chowdhuri, Z. ; Daum, M. ; Dechenaux, B. ; Emmenegger, S. ; Ferraris-Bouchez, L. ; Flaux, P. ; Geltenbort, P. ; Green, K. ; Griffith, W. C. ; Grinten, M. van der ; Harris, P. G. ; Henneck, R. ; Hild, N. ; Iaydjiev, P. ; Ivanov, S. N. ; Kasprzak, M. ; Kermaidic, Y. ; Kirch, K. ; Koch, H.-C. ; Komposch, S. ; Koss, P. A. ; Kozela, A. ; Krempel, J. ; Lauss, B. ; Lefort, T. ; Lemiere, Y. ; Leredde, A. ; Mohanmurthy, P. ; Pais, D. ; Piegsa, F. M. ; Pignol, G. ; Quéméner, G. ; Rawlik, M. ; Rebreyend, D. ; Ries, D. ; Roccia, S. ; Rozpedzik, D. ; Schmidt-Wellenburg, P. ; Schnabel, A. ; Severijns, N. ; Virot, R. ; Weis, Antoine ; Wursten, E. ; Wyszynski, G. ; Zejma, J. ; Zsigmond, G.

In: Physical Review A, 2019, vol. 99, no. 4, p. 042112

Magnetic-field uniformity is of the utmost importance in experiments to measure the electric dipole moment of the neutron. A general parametrization of the magnetic field in terms of harmonic polynomial modes is proposed, going beyond the linear- gradients approximation. We review the main undesirable effects of nonuniformities: depolarization of ultracold neutrons and Larmor frequency shifts...

Université de Fribourg

Search for axionlike dark matter through nuclear spin precession in electric and magnetic fields

Abel, C. ; Ayres, N.?J. ; Ban, G. ; Bison, G. ; Bodek, K. ; Bondar, V. ; Daum, M. ; Fairbairn, M. ; Flambaum, V.?V. ; Geltenbort, P. ; Green, K. ; Griffith, W.?C. ; Grinten, M. van der ; Grujiæ, Z.?D. ; Harris, P.?G. ; Hild, N. ; Iaydjiev, P. ; Ivanov, S.?N. ; Kasprzak, M. ; Kermaidic, Y. ; Kirch, K. ; Koch, H.-C. ; Komposch, S. ; Koss, P.?A. ; Kozela, A. ; Krempel, J. ; Lauss, B. ; Lefort, T. ; Lemi?re, Y. ; Marsh, D.?J.?E. ; Mohanmurthy, P. ; Mtchedlishvili, A. ; Musgrave, M. ; Piegsa, F.?M. ; Pignol, G. ; Rawlik, M. ; Rebreyend, D. ; Ries, D. ; Roccia, S. ; Rozpêdzik, D. ; Schmidt-Wellenburg, P. ; Severijns, N. ; Shiers, D. ; Stadnik, Y.?V. ; Weis, Antoine ; Wursten, E. ; Zejma, J. ; Zsigmond, G.

In: Physical Review X, 2017, vol. 7, no. 4, p. 041034

We report on a search for ultralow-mass axionlike dark matter by analyzing the ratio of the spin-precession frequencies of stored ultracold neutrons and 199Hg atoms for an axion-induced oscillating electric dipole moment of the neutron and an axion-wind spin-precession effect. No signal consistent with dark matter is observed for the axion mass range 10−24≤ma≤10−17 eV. Our null result...