Results 51 to 60 of about 409 (155)

Phase portraits of the Selkov model in the Poincaré disc

, 2022
Jaume Llibre, Arefeh Nabavi
openalex   +1 more source

On the Choice of Optimization Norm for Anderson Acceleration of the Picard Iteration for Navier–Stokes Equations

Numerical Methods for Partial Differential Equations, Volume 42, Issue 4, July 2026.
ABSTRACT While recent Anderson acceleration (AA) convergence theory [Pollock et al., IMA Num. An., 2021] requires that the AA optimization norm match the Hilbert space norm associated with the fixed point operator, in implementations the ℓ2$$ {\ell}^2 $$ norm is the most common choice. So far there is little research done regarding this discrepancy. To
Elizabeth Hawkins, Leo G. Rebholz
wiley   +1 more source

New Exploration of Phase Portrait Classification of Quadratic Polynomial Differential Systems Based on Invariant Theory

AppliedMath
After linear differential systems in the plane, the easiest systems are quadratic polynomial differential systems in the plane. Due to their nonlinearity and their many applications, these systems have been studied by many authors.
Joan Carles Artés, Laurent Cairó, Jaume Llibre   +2 more
doaj   +1 more source

A relative Poincaré–Birkhoff theorem

Bulletin of the London Mathematical Society, Volume 58, Issue 7, July 2026.
Abstract A. Moreno and Otto van Koert proved a generalised version of the classical Poincaré–Birkhoff theorem, for Liouville domains of any dimension. In this article, we prove a relative version for Lagrangians with Legendrian boundary. This gives interior chords of arbitrary large length, provided that the twist condition introduced by Moreno and van
Agustin Moreno, Arthur Limoge
wiley   +1 more source

An elegant model of the geodesic flow on the modular surface

Journal of the London Mathematical Society, Volume 114, Issue 1, July 2026.
Abstract Caroline Series' [The modular surface and continued fractions, J. Lond. Math. Soc. (2), 31, no. 1, (1985), 69–80] gives a clear framework linking, in a deceptively simple way, the dynamics of the geodesic flow on the modular surface with the dynamics of the regular continued fraction, through a well‐chosen symbolic coding.
Pierre Arnoux, Thomas A. Schmidt
wiley   +1 more source

The role of the curvature of a surface in the shape of the solutions to elliptic equations

Proceedings of the London Mathematical Society, Volume 133, Issue 1, July 2026.
Abstract We prove the uniqueness and nondegeneracy of the critical point of positive, semistable solutions of −Δu=f(u)$-\Delta u=f(u)$ with Dirichlet boundary conditions for a class of star‐shaped domains on the sphere and in the hyperbolic plane satisfying a geometric condition.
Francesca Gladiali, Massimo Grossi, Luigi Provenzano   +2 more
wiley   +1 more source

Higher body‐mass index modifies time‐resolved maternal autonomic cardiac–uterine coupling during the first stage of human labour

Experimental Physiology, Volume 111, Issue 7, Page 3203-3215, 1 July 2026.
Abstract We investigated whether higher body mass index (BMI) modifies time‐resolved maternal autonomic control and maternal cardio‐electrohysterographic coupling (MCEC) during the first stage of labour. Seventy‐nine women were studied and, for the present analysis, grouped as Control (C; n = 41) and high BMI (HBMI; n = 38).
Carlos Gabriel Varela‐Albarrán, José Javier Reyes‐Lagos, Laura Mercedes Santiago‐Fuentes, Guadalupe Dorantes‐Méndez, Eric Alonso Abarca‐Castro, Paula Romina Soria, Araceli Espinosa‐Guerrero   +6 more
wiley   +1 more source

Heart rate variability and autonomic function in health professions students: Associations with academic stress and lifestyle factors

Physiological Reports, Volume 14, Issue 13, July 2026.
Abstract Heart rate variability (HRV) is a non‐invasive measure of autonomic nervous system function and a sensitive marker of physiological stress. Health professions students are exposed to severe academic stress and multiple lifestyle‐related factors that may influence autonomic regulation.
Azza Alawad, Tarig Merghani, Nishaat Chowdhury, Hibat Alla Hisham   +3 more
wiley   +1 more source

Kelvin waves over a differentially rotating spherical shell

Astronomy & Astrophysics
Context. Be stars are currently viewed as B-type stars surrounded by a disc fuelled by the star itself during episodic excretion events. The origin of these events is poorly understood. Aims. This study aims to determine whether surface equatorial Kelvin
Boismard T., Rieutord M.
doaj   +1 more source

Global dynamics of a modified hybrid Van der Pol-Rayleigh oscillator II

Electronic Journal of Differential Equations
In this article, we study a modified hybrid Van der Pol-Rayleigh oscillator. We consider bifurcation diagrams and global phase portraits in the Poincare disc under some restrictions on the parameters.
Yuhuan Lu, Rui Zhang
doaj