Now showing items 41-60 of 259

    • On the origin of the inertia: the modified Newtonian dynamics theory 

      Giné, Jaume (Elsevier, 2009)
      The sameness between the inertial mass and the gravitational mass is an assumption and not a consequence of the equivalent principle is shown. In the context of the Sciama’s inertia theory, the sameness between the inertial ...
    • A survey on the inverse integrating factor 

      García, I. A. (Isaac A.); Grau Montaña, Maite (Springer, 2010)
      The relation between limit cycles of planar differential systems and the inverse integrating factor was first shown in an article of Giacomini, Llibre and Viano appeared in 1996. From that moment on, many research articles ...
    • The inverse integrating factor and the Poincaré map 

      García, I. A. (Isaac A.); Giacomini, Héctor; Grau Montaña, Maite (American Mathematical Society, 2010)
      This work is concerned with planar real analytic differential systems with an analytic inverse integrating factor defined in a neighborhood of a regular orbit. We show that the inverse integrating factor defines an ...
    • A Chebyshev criterion for Abelian integrals 

      Grau Montaña, Maite; Mañosas, Francesc; Villadelprat, Jordi (American Mathematical Society, 2010)
      We present a criterion that provides an easy sufficient condition in order that a collection of Abelian integrals has the Chebyshev property. This condition involves the functions in the integrand of the Abelian integrals ...
    • Integrability conditions for Lotka–Volterra planar complex quintic systems 

      Giné, Jaume; Romanovski, Valery G. (Elsevier, 2010)
      In this paper we obtain necessary and sufficient integrability conditions at the origin for the Lotka–Volterra complex quintic systems which are linear systems perturbed by fifth degree homogeneous polynomials, i.e., we ...
    • Competition effects in cation binding to humic acid: conditional affinity spectra for fixed total metal concentration conditions 

      David, Calin; Mongin, Sandrine; Rey Castro, Carlos; Galceran i Nogués, Josep; Companys Ferran, Encarnació; Garcés, Josep Lluís; Salvador, José; Puy Llorens, Jaume; Cecilia Averós, Joan; Lodeiro, Pablo; Mas, Francesc (Elsevier, 2010)
      Information on the Pb and Cd binding to a purified Aldrich humic acid (HA) is obtained from the influence of different fixed total metal concentrations on the acid-base titrations of this ligand. NICA (Non-Ideal Competitive ...
    • Every tree is a large subtree of a tree that decomposes Kn or Kn,n 

      Lladó, A.; López Masip, Susana-Clara; Moragas, J. (Elsevier, 2010)
      Let T be a tree with m edges. A well-known conjecture of Ringel states that every tree T with m edges decomposes the complete graph K2m+1. Graham and H¨aggkvist conjectured that T also decomposes the complete bipartite ...
    • Cyclicity versus center problem 

      Gasull i Embid, Armengol; Giné, Jaume (Springer, 2010)
      We prove that there are one-parameter families of planar differential equations for which the center problem has a trivial solution and on the other hand the cyclicity of the weak focus is arbitrarily high. We illustrate ...
    • Weierstrass integrability of differential equations 

      Giné, Jaume; Grau Montaña, Maite (Elsevier, 2010)
      The integrability problem consists in finding the class of functions a first integral of a given planar polynomial differential system must belong to. We recall the characterization of systems which admit an elementary or ...
    • 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. ...
    • Weierstrass integrability in Liénard differential systems 

      Giné, Jaume; Llibre, Jaume (Elsevier, 2011)
      In this work we study the Liénard differential systems that admit a Weierstrass first integral or a Weierstrass inverse integrating factor
    • On the planar integrable differential systems 

      Giné, Jaume; Llibre, Jaume (Springer Verlag, 2011)
      Under very general assumptions we prove that the planar differential systems having a first integral are essentially the linear differential systems u˙ = u, ˙v = v. Additionally such systems always have a Lie symmetry. We ...
    • 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 ...
    • Enumerating super edge-magic labelings for the union of nonisomorphic graphs 

      Ahmad, Ali; López Masip, Susana-Clara; Muntaner Batle, F. A.; Rius Font, Miquel (Cambridge University Press, 2011)
      A super edge-magic labeling of a graph G=(V,E) of order p and size q is a bijection f:V ∪E→{i}p+qi=1 such that: (1) f(u)+f(uv)+f(v)=k for all uv∈E; and (2) f(V )={i}pi=1. Furthermore, when G is a linear forest, the super ...
    • Super edge-magic models 

      López Masip, Susana-Clara; Muntaner Batle, F. A.; Rius Font, Miquel (Springer, 2011)
      In this paper, we generalize the concept of super edge-magic graph by introducing the new concept of super edge-magic models.
    • Vertex‐transitive graphs that remain connected after failure of a vertex and its neighbors 

      Hamidoune, Yahya Ould; Lladó, A.; López Masip, Susana-Clara (Wiley, 2011)
      A d-regular graph is said to be superconnected if any disconnecting subset with cardinality at most d is formed by the neighbors of some vertex. A superconnected graph that remains connected after the failure of a vertex ...
    • Bi-magic and other generalizations of super edge-magic labelings 

      López Masip, Susana-Clara; Muntaner Batle, F. A.; Rius Font, Miquel (Cambridge University Press, 2011)
      In this paper, we use the product ⊗h in order to study super edge-magic labelings, bi-magic labelings and optimal k-equitable labelings. We establish, with the help of the product ⊗h, new relations between super edge-magic ...
    • Can wild ungulate carcasses provide enough biomass to maintain avian scavenger populations? An empirical assessment using a bio-inspired computational model 

      Margalida, Antoni; Colomer, M. Àngels (Maria Àngels); Sanuy i Castells, Delfí (Public Library of Science (PLoS), 2011)
      Background: The reduction in the amount of food available for European avian scavengers as a consequence of restrictive public health policies is a concern for managers and conservationists. Since 2002, the application of ...
    • 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 ...
    • Effect of cattle on Salmonella carriage, diversity and antimicrobial resistance in free-ranging wild boar (Sus scrofa) in northeastern Spain 

      Navarro González, Nora; Mentaberre García, Gregorio; Porrero, Concepción M.; Serrano Ferrón, Emmanuel; Mateos, Ana; López Martín, José María; Lavín González, Santiago; Domínguez Rodríguez, Lucas (Public Library of Science, 2012)
      Salmonella is distributed worldwide and is a pathogen of economic and public health importance. As a multi-host pathogen with a long environmental persistence, it is a suitable model for the study of wildlife-livestock ...