Now showing items 110-129 of 244

    • Formal inverse integrating factors and the nilpotent center problem 

      García, I. A. (Isaac A.) (World Scientific Publishing, 2016)
      We are interested in deepening knowledge of methods based on formal power series applied to the nilpotent center problem of planar local analytic monodromic vector fields X. As formal integrability is not enough to ...
    • From Subkautz Digraphs to Cyclic Kautz Digraphs 

      Dalfó, Cristina (World Scientific Publishing, 2018)
      Kautz digraphs K(d, l) are a well-known family of dense digraphs, widely studied as a good model for interconnection networks. Closely related with these, the cyclic Kautz digraphs CK(d, l) were recently introduced by ...
    • Full-wave analysis of stripping chronopotentiograms at scanned deposition potential (SSCP) as a tool for heavy metal speciation: Theoretical development and application to Cd(II)-phthalate and Cd(II)-iodide systems 

      Serrano, N.; Díaz-Cruz, J. M.; Ariño, C.; Esteban, M.; Puy Llorens, Jaume; Companys Ferran, Encarnació; Galceran i Nogués, Josep; Cecilia Averós, Joan (Elsevier, 2007)
      A new mathematical treatment has been developed and implemented in an EXCEL spreadsheet in order to determine average equilibrium functions from the full set of data measured by scanning stripping chronopotentiometry (SSCP) ...
    • Generalization of Vélu’s formulae for isogenies between elliptic curves 

      Miret, Josep M. (Josep Maria); Moreno Chiral, Ramiro; Rio, Anna (Universitat Autònoma de Barcelona. Departament de Matemàtiques, 2007)
      Given an elliptic curve E and a finite subgroup G, V ́lu’s formulae concern to a separable isogeny IG : E → E ′ with kernel G. In particular, for a point P ∈ E these formulae express the first elementary symmetric polynomial ...
    • Geometric criterium in the center problem 

      Algaba, Antonio; García, Cristóbal; Giné, Jaume (Springer Basel, 2016-10)
      In this paper we use a geometric criterium based in the classical method of the construction of Lyapunov functions to determine if a differential system has a focus or a center at a singular point. This criterium is proved ...
    • Graphs, friends and acquaintances 

      Dalfó, Cristina; Fiol, Miguel Angel (Faculty of Mathematics and Natural SciencesInstitut Teknologi Bandung (ITB) IndonesiaIndonesian Combinatorial Society (InaCombS)GTA Research GroupGTA Research Group, 2018)
      A graph is a mathematical object modeling the existence of a certain relation between pairs of elements of a given set. Many of the first results concerning graphs made reference to relationships between groups of people. ...
    • Halving in some genus 2 curves over binary fields 

      Garra Oronich, Ricard; Miret, Josep M. (Josep Maria); Pujolàs Boix, Jordi (Institute of Electrical and Electronics Engineers (IEEE), 2016-06)
      We give a method to compute the halving of a divisor in the Jacobian variety of a genus 2 curve in characteristic 2. We present explicit halving formulae for each possible divisor class for some curves (those with h (x)= ...
    • Harvester ant nest distribution depends on soil disturbance regime 

      Baraibar Padró, Bàrbara; Torra Farré, Joel; Royo-Esnal, Aritz; Recasens i Guinjuan, Jordi; Comas Rodríguez, Carles (Elsevier, 2018-09-17)
      Nest densities of harvester ants (Messor barbarus) are high in rain-fed cereal fields in north-eastern Spain where the ants remove large quantities of seeds, contributing to reductions in weed populations. The distribution ...
    • Herramientas virtuales de simulación en la enseñanza de la astronomía diurna en futuros maestros de Primaria 

      Ibáñez, Manuel; Estrada Roca, M. Asunción; Barbero Sola, Iván (Edutec. Asociación para el Desarrollo de la Tecnología Educativa, 2017-03-01)
      Este trabajo presenta el impacto de la incorporación de herramientas virtuales de simulación de libre distribución combinadas con un modelo instruccional constructivista y dialógico en la docencia de la astronomía diurna ...
    • Human-caused fire occurrence modelling in perspective: a review 

      Costafreda Aumedes, Sergi; Comas Rodríguez, Carles; Vega García, Cristina (CSIRO Publishing, 2017)
      The increasing global concern about wildfires, mostly caused by people, has triggered the development of human-caused fire occurrence models in many countries. The premise is that better knowledge of the underlying factors ...
    • Importància didàctica de les actituds envers l'estadística en l'educació primària 

      Estrada Roca, M. Asunción (Associació de Mestres Rosa Sensat, 2013)
      L’estadística s’ha incorporat de manera generalitzada al currículum de l’Educació Primària, segons Estrada (2009), per raons fonamentalment socioculturals i educatives, i ha impulsat la investigació i el desenvolupament ...
    • Improving the peer-review process and editorial quality: key errors escaping the review and editorial process in top scientific journals 

      Margalida, Antoni; Colomer, M. Àngels (Maria Àngels) (PeerJ, 2016)
      We apply a novel mistake index to assess trends in the proportion of corrections published between 1993 and 2014 in Nature, Science and PNAS. The index revealed a progressive increase in the proportion of corrections ...
    • Inertial mass from Unruh temperatures 

      Giné, Jaume; McCulloch, M. E. (World Scientific Publishing, 2016)
      It has been proposed that inertia can be explained as follows: when objects accelerate in one direction a Rindler horizon forms in the other direction, suppressing Unruh radiation on that side, and producing a net Unruh ...
    • Inertial mass of an elementary particle from the holographic scenario 

      Giné, Jaume (World Scientific Publishing, 2017)
      Various attempts have been made to fully explain the mechanism by which a body has inertial mass. Recently it has been proposed that this mechanism is as follows: when an object accelerates in one direction a dynamical ...
    • Integrability conditions for complex kukles systems 

      Giné, Jaume; Valls, Claudia (Taylor & Francis, 2017)
      In this paper, we provide necessary and sufficient conditions for the existence of local analytic first integrals for a seventh-parameter family of complex cubic systems called the complex Kukles systems.
    • 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 ...
    • Integrability conditions of a resonant saddle in generalized Liénard-like complex polynomial differential systems 

      Giné, Jaume; Llibre, Jaume (Elsevier, 2017)
      We consider a complex differential system with a resonant saddle at the origin. We compute the resonant saddle quantities and using Gröbner bases we find the integrability conditions for such systems up to a certain degree. ...
    • Integrability conditions of a resonant saddle in Liénard-like complex systems 

      Giné, Jaume; Valls, Claudia (Elsevier, 2016)
      We consider a complex differential system with a resonant saddle that remind the classical Liénard systems in the real plane. For such systems we determine the conditions of analytic integrability of the resonant saddle.
    • Integrability conditions of a resonant saddle perturbed with homogeneous quintic nonlinearities 

      Giné, Jaume; Valls, Claudia (Springer, 2015)
      In this work we complete the integrability conditions (i.e. conditions for the existence of a local analytic first integral) for a family of a resonant saddle perturbed with homogeneous quintic nonlinearities studied in a ...
    • Integrability of a linear center perturbed by a fifth degree homogeneous polynomial 

      Chavarriga Soriano, Javier; Giné, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques, 1997)
      In this work we study the integrability of two-dimensional autonomous system in the plane with linear part of center type and non-linear part given by homogeneous polynomials of fifth degree. We give a simple characterisation ...