Now showing items 144-163 of 259

    • Integrability of planar polynomial differential systems through linear differential equations 

      Giacomini, Héctor; Giné, Jaume; Grau Montaña, Maite (Rocky Mountain Mathematics Consortium, 2006)
      In this work we consider rational ordinary differential equations dy/dx = Q(x, y)/P(x, y), with Q(x, y) and P(x, y) coprime polynomials with real coefficients. We give a method to construct equations of this type for ...
    • Integrable zero-Hopf singularities and 3-dimensional centers 

      García, I. A. (Isaac A.) (2018-01-25)
      In this paper we show that the well-known Poincaré-Lyapunov nondegenerate analytic center problem in the plane and its higher dimensional version expressed as the 3-dimensional center problem at the zero-Hopf singularity ...
    • Intra-specific association between carbon isotope composition and productivity in woody plants: A meta-analysis 

      Fardusi, Most Jannatul; Ferrio Díaz, Juan Pedro; Comas Rodríguez, Carles; Voltas Velasco, Jordi; Resco de Dios, Víctor; Serrano Endolz, Luis (Elsevier, 2016)
      The study of intra-specific variations in growth and plant physiological response to drought is crucial to understand the potential for plant adaptation to global change. Carbon isotope composition (δ13C) in plant tissues ...
    • Inverse Jacobi multiplier as a link between conservative systems and Poisson structures 

      García, I. A. (Isaac A.); Hernández Bermejo, Benito (IOP Publishing, 2017-07-15)
      Some aspects of the relationship between conservativeness of a dynamical system (namely the preservation of a finite measure) and the existence of a Poisson structure for that system are analyzed. From the local point of ...
    • Inverse Jacobi multipliers and first integrals for nonautonomous differential systems 

      Buica, Adriana; García, I. A. (Isaac A.) (Springer Basel, 2015-05-01)
      In this paper we consider nonautonomous differential systems of arbitrary dimension and first find expressions for their inverse Jacobi multipliers and first integrals in some nonautonomous invariant set in terms of the ...
    • Isogeny volcanoes of elliptic curves and sylow subgroups 

      Fouquet, Mireille; Miret, Josep M. (Josep Maria); Valera Martín, Javier (Springer International Publishing Switzerland, 2015)
      Given an ordinary elliptic curve over a finite field located in the floor of its volcano of ℓ-isogenies, we present an efficient procedure to take an ascending path from the floor to the level of stability and back to ...
    • Iterated line digraphs are asymptotically dense 

      Dalfó, Cristina (Elsevier, 2017)
      We show that the line digraph technique, when iterated, provides dense digraphs, that is, with asymptotically large order for a given diameter (or with small diameter for a given order). This is a well-known result for ...
    • Labeling constructions using digraph products 

      López Masip, Susana-Clara; Muntaner Batle, F. A.; Rius Font, Miquel (Elsevier, 2013)
      In this paper we study the edge-magicness of graphs with equal size and order, and we use such graphs and digraph products in order to construct labelings of different classes and of different graphs. We also study super ...
    • Lability and mobility effects on mixtures of ligands under steady-state conditions 

      Galceran i Nogués, Josep; Puy Llorens, Jaume; Salvador, José; Cecilia Averós, Joan; Mas i Pujadas, Francesc; Garcés, Josep Lluís (Royal Society of Chemistry, 2003)
      Analytical solutions for the steady-state flux arriving at an active surface from a mixture (in which one active species reacts with non-active ligands in the medium) can be helpful in a variety of problems: voltammetric ...
    • Lability of complexes in steady-state finite planar diffusion 

      Salvador, José; Puy Llorens, Jaume; Cecilia Averós, Joan; Galceran i Nogués, Josep (Elsevier, 2006)
      The analytical solution of the reaction-diffusion problem of a species forming a complex (with any association and dissociation rate constants) in solution and disappearing at an active planar surface is presented for a ...
    • Langford sequences and a product of digraphs 

      López Masip, Susana-Clara; Muntaner Batle, F. A. (Elsevier, 2016)
      Skolem and Langford sequences and their many generalizations have applications in numerous areas. The -product is a generalization of the direct product of digraphs. In this paper we use the -product and super edge-magic ...
    • Large restricted sumsets in general Abelian groups 

      Hamidoune, Yahya Ould; López Masip, Susana-Clara; Plagne, Alain (Elsevier, 2013)
      Let A, B and S be subsets of a finite Abelian group G. The restricted sumset of A and B with respect to S is defined as A ∧S B = {a + b : a ∈ A, b ∈ B and a − b /∈ S}. Let LS = maxz∈G |{(x, y) : x, y ∈ G, x + y = z and x ...
    • Las actitudes hacia las Matemáticas. Análisis descriptivo de un estudio de caso exploratorio centrado en la Educación Matemática de familiares 

      Estrada Roca, M. Asunción; Díez Palomar, Francisco Javier (Facultad de Ciencias de la Educación y del Deporte de la Universidad de Vigo, 2011)
      Partimos de investigaciones anteriores sobre actitudes hacia las Matemáticas y educación de personas adultas. Asumimos que las emociones son una parte importante del proceso de enseñanza y aprendizaje de las Matemáticas. ...
    • Lie symmetries and the center problem 

      Giné, Jaume (Shanghai Normal University & Wilmington Scientific Publisher, 2011)
      Abstract In this short survey we discuss the narrow relation between the center problem and the Lie symmetries. It is well known that an analytic vector field X having a non–degenerate center has a non–trivial analytic Lie ...
    • Liénard equation and its generalizations 

      Giné, Jaume (World Scientific Publishing, 2017)
      In this paper, we first present a survey of the known results on limit cycles and center conditions for Liénard differential systems. Next we propose a generalization of such systems and we study their center conditions ...
    • Limit cycles bifurcating from planar polynomial quasi--homogeneous centers 

      Giné, Jaume; Grau Montaña, Maite; Llibre, Jaume (Elsevier, 2015)
      In this paper we find an upper bound for the maximum number of limit cycles bifurcating from the periodic orbits of any planar polynomial quasi-homogeneous center, which can be obtained using first order averaging method. ...
    • Limits of the Linear Accumulation Regime of DGT Sensors 

      Mongin, Sandrine; Uribe Kaffure, Ramiro; Rey Castro, Carlos; Cecilia Averós, Joan; Galceran i Nogués, Josep; Puy Llorens, Jaume (American Chemical Society, 2013)
      A key question for the practical application of DGT (Diffusive Gradients in Thin films) as dynamic sensors in the environmental monitoring of trace metals is the influence of pH and dissolved ligands over the linear ...
    • Looking back over their shoulders: a qualitative analysis of portuguese teachers' attitudes towards statistics 

      Martins, José Alenxadre; Nascimento, Maria Manuel; Estrada Roca, M. Asunción (International Association for Statistical Education, 2012)
      Teachers’ attitudes towards statistics can have a significant effect on their own statistical training, their teaching of statistics, and the future attitudes of their students. The influence of attitudes in teaching ...
    • Magic coverings and the Kronecker product 

      López Masip, Susana-Clara; Muntaner Batle, F. A.; Rius Font, Miquel (2014)
      In this paper we study a relationship existing among (super) magic coverings and the well known Kronecker product of matrices. We also introduce the concept of Zn-property for digraphs in order to study this relation ...
    • Mixed Moore Cayley graphs 

      López Lorenzo, Ignacio; Pérez Rosés, Hebert; Pujolàs Boix, Jordi (Elsevier, 2014-09-01)
      Cayley graphs are well known objects with interesting properties, also in the context of Moore graphs and digraphs. In $1978$ Bos\'ak extended Moore's property to the mixed setting (with arcs allowed along with edges), in ...