Now showing items 21-40 of 244

    • Determination of Zn2+ concentration with AGNES using different strategies to reduce the deposition time 

      Companys Ferran, Encarnació; Cecilia Averós, Joan; Codina Montull, Glòria; Puy Llorens, Jaume; Galceran i Nogués, Josep (Elsevier, 2005)
      Absence of gradient and Nernstian equilibrium stripping (AGNES) senses the free ion concentration of Zn(II) in solutions containing different ligands, being unaffected by the lack of reversibility of the Zn2+/Zn0 couple ...
    • The problem of distinguishing between a center and a focus for nilpotent and degenerate analytic systems 

      Giacomini, Héctor; Giné, Jaume; Llibre, Jaume (Elsevier, 2006)
      In this work we study the centers of planar analytic vector fields which are limit of linear type centers. It is proved that all the nilpotent centers are limit of linear type centers and consequently the Poincaré–Liapunov ...
    • 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 ...
    • 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 ...
    • Análisis de las actitudes y conocimientos estadísticos elementales en la formación del profesorado 

      Estrada Roca, M. Asunción; Batanero, Carmen; Fortuny, Josep Maria (Universidad Autónoma de Madrid, 2006)
      Resumimos la tesis doctoral de Dña Assumpta Estrada Roca, dirigida por Carmen Batanero y Josep María Fortuny, y presentada en la Universidad Autónoma de Barcelona en septiembre de 2002, reflexionando sobre las implicaciones ...
    • Evaluación del conocimiento estadístico en la formación inicial del profesorado 

      Estrada Roca, M. Asunción (Graó, 2007)
      Analizamos la educación estadística de los profesores en formación y presentamos un estudio de evaluación de los conocimientos estadísticos elementales de una muestra de 367 estudiantes de diferentes especialidades de ...
    • The role of algebraic solutions in planar polynomial differential systems 

      Giacomini, Héctor; Giné, Jaume; Grau Montaña, Maite (Cambridge University Press, 2007)
      We study a planar polynomial differential system, given by . We consider a function , where gi(x) are algebraic functions of with ak(x) and algebraic functions, A0(x,y) and A1(x,y) do not share any common factor, h2(x) is ...
    • 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 ...
    • Review of mathematical models for sow herd management 

      Pla Aragonés, Lluís Miquel (Elsevier, 2007)
      This paper is a survey of the different sow models described in literature, which made use of different mathematical methodologies, and were intended for sow herd management. Models were discussed under a wide classification, ...
    • Volcanoes of l-isogenies of elliptic curves over finite fields: the case l=3 

      Miret, Josep M. (Josep Maria); Sadornil Renedo, Daniel; Tena Ayuso, Juan; Tomàs Cuñat, Rosa Ana; Valls Marsal, Magda (Universitat Autònoma de Barcelona. Departament de Matemàtiques, 2007)
      This paper is devoted to the study of the volcanoes of l-isogenies of elliptic curves over a finite field, focusing on their height as well as on the location of curves across its different levels. The core of the paper ...
    • Algorithms and cryptographic protocols using elliptic curves 

      Miret, Josep M. (Josep Maria); Moreno Chiral, Ramiro; Pujolàs Boix, Jordi; Valls Marsal, Magda (Institut d'Estudis Catalans. Secció de Ciències i Tecnologia, 2007)
      En els darrers anys, la criptografia amb corbes el.líptiques ha adquirit una importància creixent, fins a arribar a formar part en la actualitat de diferents estàndards industrials. Tot i que s'han dissenyat variants amb ...
    • Errores en el cálculo de probabilidades en tablas de doble entrada en profesores en formación 

      Estrada Roca, M. Asunción; Díaz, Carmen (Graó, 2007-01)
      La lectura e interpretación de tablas de doble entrada es un elemento básico de la cultura estadística de cualquier ciudadano, y los futuros profesores, que serán los responsables de su enseñanza a los niños, deberían ...
    • Non existence of almost Moore digraphs of diameter three 

      Conde Colom, Josep; Gimbert i Quintilla, Joan; Miret, Josep M. (Josep Maria); Moreno Chiral, Ramiro; Gonzàlez, J. (Electronic Journal of Combinatorics, 2008)
      Almost Moore digraphs appear in the context of the degree/diameter problem as a class of extremal directed graphs, in the sense that their order is one less than the unattainable Moore bound M(d; k) = 1 + d + + dk, where ...
    • On the origin of the deflection of light 

      Giné, Jaume (Elsevier, 2008)
      Action at distance in Newtonian physics is replaced by finite propagation speeds in classical post–Newtonian physics. As a result, the differential equations of motion in Newtonian physics are replaced by functional ...
    • Exploiting isogeny cordillera structure to obtain cryptographically good elliptic curves 

      Miret, Josep M. (Josep Maria); Tomàs, Rosana; Valls Marsal, Magda; Sadornil Renedo, Daniel; Tena Ayuso, Juan (Australian Computer Society Inc, 2008)
      The security of most elliptic curve cryptosystems is based on the intractability of the Elliptic Curve Discrete Logarithm Problem (ECDLP). Such a problem turns out to be computationally unfeasible when elliptic curves ...
    • 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 ...
    • Secure many-to-one communications in wireless sensor networks 

      Viejo Galicia, Alexandre; Domingo i Ferrer, Josep; Sebé Feixas, Francesc; Castellà Roca, Jordi (Molecular Diversity Preservation International (MDPI), 2009)
      Wireless Sensor Networks (WSN) are formed by nodes with limited computational and power resources. WSNs are finding an increasing number of applications, both civilian and military, most of which require security for the ...
    • A two-stage stochastic programming model for scheduling replacements in sow farms 

      Rodríguez Sánchez, Sara Verónica; Albornoz Sanhueza, Victor Manuel; Pla Aragonés, Lluís Miquel (Springer Verlag, 2009)
      This paper presents a formulation and resolution of a two-stage stochastic linear programming model with recourse for sow farms producing piglets. The proposed model considers a medium-term planning horizon and specifically ...
    • 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 ...