Ara es mostren els items 5-24 de 30

    • Càlcul numèric : manual de pràctiques 

      Lázaro Ochoa, José Tomás; Ollé Torner, Mercè; Pacha Andújar, Juan Ramón (Universitat Politècnica de Catalunya, 2014)
      Pràctica
      Accés obert
    • Càlcul numèric. Manual de pràctiques 

      Lázaro Ochoa, José Tomás; Ollé Torner, Mercè; Pacha Andújar, Juan Ramón (2014-07)
      Report de recerca
      Accés obert
    • Critical slowing down close to a global bifurcation of a curve of quasi-neutral equilibria 

      Fontich Julia, Ernest; Guillamon Grabolosa, Antoni; Lázaro Ochoa, José Tomás; Alarcón, Tomás; Vidiella, Blai; Sardanyes, Josep (2022-01)
      Article
      Accés obert
      Critical slowing down arises close to bifurcations and involves long transients. Despite slowing down phenomena have been widely studied in local bifurcations i.e., bifurcations of equilibrium points, less is known about ...
    • Decay of HCoV-OC43 infectivity is lower in cell debris-containing media than in fresh culture media 

      Lázaro Ochoa, José Tomás; Elena, Santiago; Muñoz Sánchez, Juan Carlos; Hillung, Julia; Olmo Uceda, Maria-José; Sardañés, Josep (2024-02-16)
      Article
      Accés obert
      In the quantitative description of viral dynamics within cell cultures and, more broadly, in modeling within-host viral infections, a question that commonly arises is whether the degradation of a fraction of the virus could ...
    • Differential galois theory and non-integrability of planar polynomial vector fields 

      Lázaro Ochoa, José Tomás; Pantazi, Chara; Acosta Humanez, Primitivo; Morales Ruiz, Juan José (2018-02-26)
      Article
      Accés restringit per política de l'editorial
      We study a necessary condition for the integrability of the polynomials vector fields in the plane by means of the differential Galois Theory. More concretely, by means of the variational equations around a particular ...
    • Dynamics and bifurcations in a simple quasispecies model of tumorigenesis 

      Castillo, Vanessa; Lázaro Ochoa, José Tomás; Sardañés, Josep (2015-05-18)
      Article
      Accés obert
      Cancer is a complex disease and thus is complicated to model. However, simple models that describe the main processes involved in tumoral dynamics, e.g., competition and mutation, can give us clues about cancer behavior, ...
    • Dynamics in a time-discrete food-chain model with strong pressure on preys 

      Lázaro Ochoa, José Tomás; Alsedà, Lluís; Vidiella, Blai; Solé Vicente, Ricard; Sardañés, Josep (2020-05-01)
      Article
      Accés obert
      Discrete-time dynamics, mainly arising in boreal and temperate ecosystems for species with non-overlapping generations, have been largely studied to understand the dynamical outcomes due to changes in relevant ecological ...
    • Effective stability in reversible systems 

      Delshams Valdés, Amadeu; Lázaro Ochoa, José Tomás (1997)
      Article
      Accés obert
      In this paper we present a procedure to put in normal form a nearly-integrable reversible system, not necessarily a Hamiltonian system. Furthermore, non-resonant stability estimates are obtained. As an application we discuss ...
    • Full analysis of small hypercycles with short-circuits in prebiotic evolution 

      Lázaro Ochoa, José Tomás; Guillamon Grabolosa, Antoni; Fontich, Ernest; Sardañés, Josep (2017-01-05)
      Article
      Accés obert
      It is known that hypercycles are sensitive to the so-called parasites and short-circuits. While the impact of parasites has been widely investigated for well-mixed and spatial hypercycles, the effect of short-circuits in ...
    • Mixed dynamics in reversible maps with gure-8 homoclinic connections 

      Delshams Valdés, Amadeu; Gonchenko, Sergey; Lázaro Ochoa, José Tomás (2014)
      Text en actes de congrés
      Accés obert
      We study dynamics and bifurcations of two-dimensional reversible maps having non-transversal heteroclinic cycles containing symmetric saddle periodic points. We consider one-parameter families of rev ersible maps unfolding ...
    • Mixed dynamics of two-dimensional reversible maps with a symmetric couple of quadratic homoclinic tangencies 

      Lázaro Ochoa, José Tomás; Delshams Valdés, Amadeu; Gonchenko, Marina; Gonchenko, Sergey (American Institute of Mathematical Sciences, 2018-09)
      Article
      Accés obert
      We study dynamics and bifurcations of 2-dimensional reversible maps having a symmetric saddle fixed point with an asymmetric pair of nontransversal homoclinic orbits (a symmetric nontransversal homoclinic figure-8). We ...
    • On dynamics and invariant sets in predator-prey maps 

      Lázaro Ochoa, José Tomás; Alsedà, Lluís; Sardañés, Josep; Vidiella, Blai (2019-11-27)
      Capítol de llibre
      Accés obert
      A multitude of physical, chemical, or biological systems evolving in discrete time can be modelled and studied using difference equations (or iterative maps). Here we discuss local and global dynamics for a predator-prey ...
    • On Normal Forms and Splitting of Separatrices in Reversible Systems 

      Lázaro Ochoa, José Tomás (Universitat Politècnica de Catalunya, 2003-10-23)
      Tesi
      Accés obert
      És difícil dibuixar una frontera, dins la Teoria de Sistemas Dinàmics, entre lleis de conservació i simetries doncs, sovint, les seves característiques es confonen. Un clar exemple d'aquest fenómen el constitueixen els ...
    • On the Chebyshev property for a new family of functions 

      Lázaro Ochoa, José Tomás; Gasull Embid, Armengol; Torregrosa, Joan (2012-03)
      Article
      Accés obert
    • On the integrability of polynomial fields in the plane by means of Picard-Vessiot theory 

      Lázaro Ochoa, José Tomás; Morales Ruíz, Juan José; Acosta Humánez, Primitivo Belén; Pantazi, Chara (2012-01-12)
      Report de recerca
      Accés obert
      We study the integrability of polynomial vector fields using Galois theory of linear differential equations when the associated foliations is reduced to a Riccati type foliation. In particular we obtain integrability results ...
    • On the integrability of polynomial vector fields in the plane by means of Picard-Vessiot theory 

      Acosta-Humànez, Primitivo; Lázaro Ochoa, José Tomás; Morales Ruiz, Juan José; Pantazi, Chara (American Institute of Mathematical Sciences, 2015-05-01)
      Article
      Accés obert
      We study the integrability of polynomial vector fields using Galois theory of linear differential equations when the associated foliations is reduced to a Riccati type foliation. In particular we obtain integrability results ...
    • Pseudo-normal form near saddle-center or saddle-focus equilibria 

      Delshams Valdés, Amadeu; Lázaro Ochoa, José Tomás (2003)
      Article
      Accés obert
      In this paper we introduce the pseudo-normal form, which generalizes the notion of normal form around an equilibrium. Its convergence is proved for a general analytic system in a neighborhood of a saddle-center or a ...
    • Pseudo-normal forms and their applications 

      Delshams Valdés, Amadeu; Lázaro Ochoa, José Tomás (2001)
      Article
      Accés obert
    • Rational parameterizations approach for solving equations in some dynamical systems problems 

      Lázaro Ochoa, José Tomás; Gasull Embid, Armengol; Torregrosa Arús, Joan (2019-08)
      Article
      Accés obert
      We show how the use of rational parameterizations facilitates the study of the number of solutions of many systems of equations involving polynomials and square roots of polynomials. We illustrate the effectiveness of this ...
    • Semiclassical quantification of some two degree of freedom potentials: A differential Galois approach 

      Acosta Humánez, Primitivo Belen; Lázaro Ochoa, José Tomás; Pantazi, Chara; Morales Ruiz, Juan José (2024-01-01)
      Article
      Accés obert
      In this work we explain the relevance of the Differential Galois Theory in the semiclassical (or WKB) quantification of some two degree of freedom potentials. The key point is that the semiclassical path integral quantification ...