Results 61 to 70 of about 49,230 (203)

Analytical Solutions for the Cardiac Extracellular‐Membrane‐Intracellular Model

Mathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT The cardiac extracellular‐membrane‐intracellular (EMI) model is a novel mathematical framework for cardiac electrophysiology simulations. The cardiac EMI model provides a more detailed description of the heart's electrical activity compared to traditional monodomain and bidomain models, potentially making it better‐suited for understanding the
Carlos Ballesteros, Alexei Cheviakov, Raymond J. Spiteri   +2 more
wiley   +1 more source

The Real and Complex Techniques in Harmonic Analysis from the Point of View of Covariant Transform

, 2014
This note reviews complex and real techniques in harmonic analysis. We describe a common source of both approaches rooted in the covariant transform generated by the affine group.
Kisil, Vladimir V.
core  

Asymptotics for the Spectrum of the Laplacian in Thin Bars with Varying Cross Sections

Mathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT We consider spectral problems for the Laplace operator in 3D rod structures with a small cross section of diameter O(ε)$$ O\left(\varepsilon \right) $$, ε$$ \varepsilon $$ being a positive parameter. The boundary conditions are Dirichlet (Neumann, respectively) on the bases of this structure, and Neumann on the lateral boundary.
Pablo Benavent‐Ocejo, Delfina Gómez, Maria‐Eugenia Pérez‐Martínez   +2 more
wiley   +1 more source

Existence Analysis of a Three‐Species Memristor Drift‐Diffusion System Coupled to Electric Networks

Mathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT The existence of global weak solutions to a partial‐differential‐algebraic system is proved. The system consists of the drift‐diffusion equations for the electron, hole, and oxide vacancy densities in a memristor device, the Poisson equation for the electric potential, and the differential‐algebraic equations for an electric network.
Ansgar Jüngel, Tuấn Tùng Nguyến
wiley   +1 more source

From Stability to Chaos: A Complete Classification of the Damped Klein‐Gordon Dynamics

Mathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT We investigate the transition between stability and chaos in the damped Klein‐Gordon equation, a fundamental model for wave propagation and energy dissipation. Using semigroup methods and spectral criteria, we derive explicit thresholds that determine when the system exhibits asymptotic stability and when it displays strong chaotic dynamics ...
Carlos Lizama, Marina Murillo‐Arcila, Julio Puerta‐Fernández   +2 more
wiley   +1 more source

Dynamic Contrast Enhanced—Magnetic Resonance Fingerprinting (DCE‐MRF) Improves Detection of Induced Vascular Perfusion Reduction in a Mouse Breast Cancer Model

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Dynamic contrast‐enhanced MRI (DCE‐MRI) can assess tumor perfusion using pharmacokinetic models. However, poor DCE‐MRI reproducibility from reliance on conventional T1‐weighted MRI has limited clinical translation. We evaluated whether Dynamic Contrast Enhanced‐Magnetic Resonance Fingerprinting (DCE‐MRF), which directly generates ...
Christina J. MacAskill, Bernadette O. Erokwu, Yuran Zhu, Guanhua Wang, Andrew Dupuis, Barbara J. Schiemann, Gopalakrishnan Ramamurthy, Chetan B. Dhakan, Michael Kavran, Chunying Wu, William P. Schiemann, Yilun Sun, Mark A. Griswold, Xin Yu, Mark D. Pagel, Chris A. Flask   +15 more
wiley   +1 more source

Free‐Running Three‐Dimensional Cardiac Extracellular Volume Mapping in a Single Scan With Mid‐Scan Contrast Injection

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To develop a new method for free‐running three‐dimensional (3D) extracellular volume mapping of the heart in a single scan with mid‐scan contrast injection. Methods 3D cardiac MR imaging was performed with a single scan that acquired k‐space data continuously using an inversion recovery (IR) sequence with a spoiled gradient‐echo ...
Wonil Lee, Paul Kyu Han, Thibault Marin, Ismaël B. G. Mounime, Didi Chi, Felicitas J. Bijari, Marc D. Normandin, Georges El Fakhri, Chao Ma   +8 more
wiley   +1 more source

Phase‐Pole‐Free Images and Smooth Coil Sensitivity Maps by Regularized Nonlinear Inversion

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Phase singularities are a common problem in image reconstruction with auto‐calibrated sensitivities due to an inherent ambiguity of the estimation problem. The purpose of this work is to develop a method for detecting and correcting phase poles in non‐linear inverse (NLINV) reconstruction of MR images and coil sensitivity maps ...
Moritz Blumenthal, Martin Uecker
wiley   +1 more source

On the orbit of invariant subspaces of linear operators in finite-dimensional spaces (new proof of a Halmos's result)

Linear Algebra and its Applications, 2001
The fact that for any linear operator \(A\) on a finite-dimensional complex vector space, the lattice of invariant subspaces of \(A\) coincides with the set of ranges of the operators which commute with \(A\), was pointed out by \textit{P. R. Halmos} [Linear Algebra Appl. 4, 11-15 (1971; Zbl 0264.15001)].
openaire   +1 more source

Explicit‐Implicit Material Point Method for Dense Granular Flows With a Novel Regularized µ(I) Model

International Journal for Numerical and Analytical Methods in Geomechanics, EarlyView.
ABSTRACT The material point method (MPM) is widely employed to simulate granular flows. Although explicit time integration is favored in most current MPM implementations for its simplicity, it cannot rigorously incorporate the incompressible µ(I)‐rheology, an efficient model ubiquitously adopted in other particle‐based numerical methods. While operator‐
Hang Feng, Zhen‐Yu Yin
wiley   +1 more source