Results 41 to 50 of about 505,503 (271)

On the dynamics of the autonomous Duffing–Holmes oscillator

Nonlinear Analysis
The autonomous Duffing–Holmes oscillator ẋ = y,  ẏ = x – x3 + by – kz,  ż = w(y – z), depending on the three parameters b, k, and w, has been studied previously by several authors who showed that for certain parameter values, it exhibits chaotic ...
Érika Diz-Pita, Jaume Jaume Llibre, M. Victoria Otero-Espinar   +2 more
doaj   +1 more source

Computation of focus quantities of three-dimensional polynomial systems

上海师范大学学报. 自然科学版, 2014
Fix a collection of polynomial vector fields on R3 with a singularity at the origin,for every one of which the linear part at the origin has two pure imaginary and one non-zero eigenvalue.Some such systems admit a local analytic first integral,which then
Valery G. Romanovski, Douglas S. Shafer
doaj   +1 more source

Invariant Algebraic Curves and Rational First Integrals for Planar Polynomial Vector Fields

Journal of Differential Equations, 2001
Let \({\mathcal X}(x,y)=p(x,y){{\partial}\over{\partial x}}+q(x,y){{\partial}\over{\partial y}}\) be a planar polynomial (real or complex) vector field of degree \(m,\) having an invariant algebraic solution of degree \(n,\) \(f(x,y)=0,\) i.e. \({\mathcal X}(f)=k f\) for some polynomial \(k(x,y)\) of degree \(m-1\) called the cofactor of \(f.\) Denote ...
Chavarriga, Javier, Llibre, Jaume
openaire   +1 more source

On the integrability and dynamics of the Hide, Skeldon and Acheson differential system

Electronic Journal of Qualitative Theory of Differential Equations
The family of systems \begin{equation*} \dot{x}= x(y-1)-\beta z,\quad \dot{y}= \alpha (1-x^2)-\kappa y, \quad \dot{z}= x-\lambda z, \end{equation*} where $(x,y,z) \in \mathbb{R}^3$ and $\alpha$, $\beta$, $\kappa$, $\lambda$ are real parameters, was ...
Érika Diz-Pita, Jaume Llibre, M. Victoria Otero-Espinar, Claudia Valls   +3 more
doaj   +1 more source

Towards complex(rational) powers of free fields, generalized $\beta\gamma$ systems and non-polynomial quantum field theory

, 1994
The $\beta\gamma$ system is generalized by complex(rational) powers of the fields, which leads to a corresponding extension on the Fock space. Two different approaches to compute the Green functions of the physical operators are proposed.
Andreev, Oleg
core   +1 more source

Phosphatidylinositol 4‐kinase as a target of pathogens—friend or foe?

FEBS Letters, EarlyView.
This graphical summary illustrates the roles of phosphatidylinositol 4‐kinases (PI4Ks). PI4Ks regulate key cellular processes and can be hijacked by pathogens, such as viruses, bacteria and parasites, to support their intracellular replication. Their dual role as essential host enzymes and pathogen cofactors makes them promising drug targets.
Ana C. Mendes, Guilherme M. Azevedo, Amanda P. Barcellos, Diana Bahia   +3 more
wiley   +1 more source

Structural biology of ferritin nanocages

FEBS Letters, EarlyView.
Ferritin is a conserved iron‐storage protein that sequesters iron as a ferric mineral core within a nanocage, protecting cells from oxidative damage and maintaining iron homeostasis. This review discusses ferritin biology, structure, and function, and highlights recent cryo‐EM studies revealing mechanisms of ferritinophagy, cellular iron uptake, and ...
Eloise Mastrangelo, Flavio Di Pisa
wiley   +1 more source

Quadratic Chabauty for (bi)elliptic curves and Kim's conjecture

, 2020
We explore a number of problems related to the quadratic Chabauty method for determining integral points on hyperbolic curves. We remove the assumption of semistability in the description of the quadratic Chabauty sets $\mathcal{X}(\mathbb{Z}_p)_2 ...
Bianchi, Francesca
core   +1 more source

A methionine‐lined active site governs carbocation stabilization and product specificity in a bacterial terpene synthase

FEBS Letters, EarlyView.
This study reveals a unique active site enriched in methionine residues and demonstrates that these residues play a critical role by stabilizing carbocation intermediates through novel sulfur–cation interactions. Structure‐guided mutagenesis further revealed variants with significantly altered product profiles, enhancing pseudopterosin formation. These
Marion Ringel, Carl P. O. Helmer, Shani Zev, Ronja Driller, Emily Buhr, Markus Reinbold, Renana Schwartz, Gabriel Foley, Mikael Boden, Daniel Garbe, Gerhard Schenk, Dan Thomas Major, Bernhard Loll, Thomas Brück   +13 more
wiley   +1 more source

Soliton solutions of the generalized Davey-Stewartson equation with full nonlinearities via three integrating schemes

Ain Shams Engineering Journal, 2021
This paper considers the generalized Davey-Stewartson equation that is used to investigate the dynamics of wave propagation in water of finite depth under the effects of gravity force and surface tension.
Saima Arshed, Nauman Raza, Monairah Alansari   +2 more
doaj   +1 more source