Recent Submissions

  • Center conditions and limits cycles for bilienard systems 

    Giné, Jaume (Texas State University, 2017)
    In this article we study the center problem for polynomial BiLiénard systems of degree n. Computing the focal values and using Gröbner bases we end the center conditions for such systems for n = 6. We also establish ...
  • Accumulation of Mg to Diffusive Gradients in Thin Films (DGT) devices: Kinetic and thermodynamic effects of the ionic strength 

    Altier, Alexandra; Jiménez-Piedrahita, Martín; Rey Castro, Carlos; Cecilia Averós, Joan; Galceran i Nogués, Josep; Puy Llorens, Jaume (American Chemical Society, 2016-09-23)
    Availability of magnesium is a matter of concern due to its role in many environmental and biological processes. Diffusive Gradients in Thin Films (DGT) devices can measure Mg availability in situ. This work shows that Mg ...
  • 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)= ...
  • Nilpotent centres via inverse integrating factors 

    Algaba, Antonio; García, Cristóbal; Giné, Jaume (Cambridge University Press, 2016-10)
    In this paper we are interested in the nilpotent center problem of planar analytic monodromic vector fields. It is known that the formal integrability is not enough to characterize such centers. More general objects are ...
  • 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 ...
  • Dynamics of competition over water in a mixed oak-pine Mediterranean forest: spatio-temporal and physiological components 

    Castillo Díaz, Jorge del; Comas Rodríguez, Carles; Voltas Velasco, Jordi; Ferrio Díaz, Juan Pedro (Elsevier, 2016-12-15)
    Understanding inter- and intra-specific plant interactions and competition over water is challenging because of the lack of effective approaches for accessing and monitoring root distribution and activity. In this context, ...
  • 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 ...
  • Analysing spatial correlation of weeds and harvester ants in cereal fields using point processes 

    Comas Rodríguez, Carles; Royo-Esnal, Aritz; Recasens i Guinjuan, Jordi; Torra Farré, Joel (Springer Verlag, 2016)
    The interaction between the spatial distribution of weed richness and weed cover and the spatial location of harvester ant nets was investigated in cereal fields. The understanding of such interdependencies can be relevant ...
  • Estudio exploratorio de las respuestas de los estudiantes para maestro sobre el uso de la noción de medida en tareas matemáticas 

    Estrada Roca, M. Asunción; Moreno Moreno, Ma. del Mar; Huszar, Gabriel; Barbero Sola, Iván (Universitat Rovira i Virgili. Departament de Pedagogia, 2016)
    El siguiente informe de investigación aporta resultados sobre las respuestas a la prueba diagnóstica preparada ad hoc para la investigación que se está realizando con los estudiantes de primer curso del grado de Maestro ...
  • Analytic reducibility of nondegenerate centers: Cherkas systems 

    Giné, Jaume; Llibre, Jaume (Bolyai Institute, University of SzegedHungarian Academy of Sciences, 2016)
    In this paper we study the center problem for polynomial differential systems and we prove that any center of an analytic differential system is analytically reducible. x˙=y,y˙=P0(x)+P1(x)y+P2(x)y2, We also study the ...
  • Sequence Mixed Graphs 

    Dalfó, Cristina; Fiol, Miguel Angel; López Lorenzo, Ignacio (Elsevier, 2017-01-20)
    A mixed graph can be seen as a type of digraph containing some edges (or two opposite arcs). Here we introduce the concept of sequence mixed graphs, which is a generalization of both sequence graphs and iterated line ...
  • Evaluación de la sustentabilidad del sistema agrícola de la Comunidad de Huapra (Perú) 

    Espinola, Jesús E.; Pla Aragonés, Lluís Miquel; Montañez, Eddy J.; Leyva, Jorge W.; Cáceres, Vladimir A. (Universidad de la Habana, 2017)
    This paper assesses the agricultural sustainability of the peasant community of Huapra, located in the Andes of Peru; this is a type of high land farming communities. The analysis has been made by applying the methodology ...
  • Integrability of Liénard systems with a weak saddle 

    Gasull i Embid, Armengol; Giné, Jaume (Springer International Publishing, 2017)
    We characterize the local analytic integrability of weak saddles for complex Li´enard systems, x˙ = y−F(x), y˙ = ax, 0 = a ∈ C, with F analytic at 0 and F(0) = F (0) = 0. We prove that they are locally integrable at the ...
  • A privacy-preserving reputation system with user rewards 

    Busom Figueres, Núria; Petrlic, R.; Sebé Feixas, Francesc; Sorge, C.; Valls Marsal, Magda (Elsevier, 2017)
    Reputation systems are useful to assess the trustworthiness of potential transaction partners, but also a potential threat to privacy since rating profiles reveal users’ preferences. Anonymous reputation systems resolve this ...
  • Clan information market games 

    El Obadi, Saadia; Miquel Fernández, Silvia (Springer US, 2016)
    We introduce a TU-game that describes a market where information is distributed among several agents and all these pieces of information are necessary to produce a good. This situation will be called clan information market. ...
  • 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 ...
  • The center problem for a 2:-3 resonant cubic Lotka–Volterra system 

    Dolićanin, Diana; Giné, Jaume; Oliveira, Regilene; Romanovski, Valery G. (Elsevier, 2013)
    In this paper we obtain conditions on the coefficients of a cubic Lotka–Volterra system of the form equation(1) x=x(2-a20x2-a11xy-a02y2), ẏ=y(-3+b20x2+b11xy+b02y2), which fulfillment yields the existence in a ...
  • Sex-related differences in body condition and serum biochemical parameters in red deer (Cervus elaphus) naturally infected with Mycobacterium bovis 

    López Olvera, J. R.; Fernández de Mera, I. G.; Vidal, D.; Vicente, J.; Fierro, Y.; Gortázar, C.; Serrano Ferrón, Emmanuel (Elsevier, 2013)
    Although Mycobacterium bovis infection is commonly reported in red deer (Cervus elaphus), potential differences in the effects of infection on male and female animals in terms of body condition and clinical biochemistry ...
  • The three-dimensional center problem for the zero-Hopf singularity 

    García, I. A. (Isaac A.); Valls, Claudia (American Institute of Mathematical Sciences, 2016-03-01)
    In this work we extend well-known techniques for solving the Poincar\'e-Lyapunov nondegenerate analytic center problem in the plane to the 3-dimensional center problem at the zero-Hopf singularity. Thus we characterize the ...
  • Cyclicity of a class of polynomial nilpotent center singularities 

    García, I. A. (Isaac A.); Shafer, Douglas S. (American Institute of Mathematical Sciences, 2016-04-01)
    In this work we extend techniques based on computational algebra for bounding the cyclicity of nondegenerate centers to nilpotent centers in a natural class of polynomial systems, those of the form $\dot x = y + P_{2m + ...

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