Juan Campos - Academia.edu (original) (raw)
Papers by Juan Campos
Courriel : gossez@ulb.ac.be (Reçu le 11 septembre 2000, accepté le 6 novembre 2000)
Scientia Horticulturae, 2010
The possibility of applying grafting to improve fruit quality has been scarcely investigated. Dif... more The possibility of applying grafting to improve fruit quality has been scarcely investigated. Different shoot tomato (Solanum lycopersicum) genotypes were grafted onto distinctly-different tomato rootstocks and the effect of the rootstock on two important fruit quality parameters, soluble solids content (SSC) and titratable acidity (TA), was studied under both non-saline and saline conditions. Increased SSC and TA in fruits from grafted plants grown under saline conditions were observed on different grafting combinations. One of these rootstocks (cv. Radja) was able to induce increases in both fruit yield and fruit quality traits of the scion. When recombinant inbred lines (RILs) from the crossing of the cultivated tomato and wild tomato (Solanum cheesmaniae) were tested as rootstocks, using the commercial hybrid 'Boludo' as scion, the rootstock also improved SSC and TA when grafted plants were grown under non-saline conditions. On the whole, these results show the effectiveness of grafting with respect to upgrading of fruit quality in tomato, which is of great importance as grafting is a rapid and efficient alternative to achieve this goal.
Nonlinearity, 2004
We prove the existence of periodic orbits with minimal period greater than any prescribed number ... more We prove the existence of periodic orbits with minimal period greater than any prescribed number for a natural Lagrangian autonomous system in several variables that is analytic and periodic in each variable and whose potential is nonconstant.
Nonlinear Analysis: Theory, Methods & Applications, 1996
Nonlinear Analysis: Theory, Methods & Applications, 2008
In this work we consider the following problem
Journal of Differential Equations, 2014
We prove that linear almost periodic systems always carry almost automorphic dynamics, thus confi... more We prove that linear almost periodic systems always carry almost automorphic dynamics, thus confirming in this case a more general conjecture by Shen and Yi. The result is based on the accurate description of the breakdown of the Favard separation condition.
Journal of Differential Equations, 2013
We consider the scalar differential equationu = f (u) + c h(t) where f (u) is a jumping nonlinear... more We consider the scalar differential equationu = f (u) + c h(t) where f (u) is a jumping nonlinearity and h(t) is an almost periodic function, while c is a real parameter deciding the size of the forcing term. The main result is that, if h(t) does not vanish too much in some suitable sense, then the equation admits a (unique) almost periodic solution for large values of the parameter c. The class of the h(t)'s to which the result applies is studied in detail: it includes all the nontrivial trigonometric polynomials and is generic in the Baire sense.
Comptes Rendus Mathematique, 2012
This note is devoted to several inequalities deduced from a special form of the logarithmic Hardy... more This note is devoted to several inequalities deduced from a special form of the logarithmic Hardy-Littlewood-Sobolev, which is well adapted to the characterization of stationary solutions of a Keller-Segel system written in self-similar variables, in case of a subcritical mass. For the corresponding evolution problem, such functional inequalities play an important role for identifying the rate of convergence of the solutions towards the stationary solution with same mass. Hardy-Littlewood-Sobolev inequality; Onofri's inequality; Legendre duality; best constants -MSC (2010): Primary: 26D10; 92C17. Secondary: 35B40
Communications in Partial Differential Equations, 2014
We investigate the large-time behavior of the solutions of the two-dimensional Keller-Segel syste... more We investigate the large-time behavior of the solutions of the two-dimensional Keller-Segel system in self-similar variables, when the total mass is subcritical, that is less than 8 π after a proper adimensionalization. It was known from previous works that all solutions converge to stationary solutions, with exponential rate when the mass is small. Here we remove this restriction and show that the rate of convergence measured in relative entropy is exponential for any mass in the subcritical range, and independent of the mass. The proof relies on symmetrization techniques, which are adapted from a paper of J.I. Diaz, T. Nagai, and J.-M. Rakotoson, and allow us to establish uniform estimates for L p norms of the solution. Exponential convergence is obtained by the mean of a linearization in a space which is defined consistently with relative entropy estimates and in which the linearized evolution operator is self-adjoint. The core of proof relies on several new spectral gap estimates which are of independent interest. R 2 n 0 dx < 8 π , then there exists a solution u, in the sense of distributions, that is global in time and such that M = R 2 u(t, x) dx is conserved along the evolution in the euclidean space R 2 . There is no non-trivial stationary solution of (1.1) and any solution converges to zero locally as time gets large. In order to study the asymptotic behavior of u, it is convenient to work in self-similar variables. We define R(t) := √ 1 + 2 t, τ (t) := log R(t), and the rescaled functions n and c by u(t, x) := R −2 (t) n τ (t), R −1 (t) x and v(t, x) := c τ (t), R −1 (t) x .
Communications in Mathematical Physics, 2010
We study a three dimensional continuous model of gravitating matter rotating at constant angular ... more We study a three dimensional continuous model of gravitating matter rotating at constant angular velocity. In the rotating reference frame, by a finite dimensional reduction, we prove the existence of non radial stationary solutions whose supports are made of an arbitrarily large number of disjoint compact sets, in the low angular velocity and large scale limit. At first order, the solutions behave like point particles, thus making the link with the relative equilibria in N -body dynamics.
Annali di Matematica Pura ed Applicata, 2006
This paper uses topological degree methods to prove the existence of periodic solutions of some q... more This paper uses topological degree methods to prove the existence of periodic solutions of some quaternionic-valued ordinary differential equations.
Buscando seguridad y eficiencia.
Courriel : gossez@ulb.ac.be (Reçu le 11 septembre 2000, accepté le 6 novembre 2000)
Scientia Horticulturae, 2010
The possibility of applying grafting to improve fruit quality has been scarcely investigated. Dif... more The possibility of applying grafting to improve fruit quality has been scarcely investigated. Different shoot tomato (Solanum lycopersicum) genotypes were grafted onto distinctly-different tomato rootstocks and the effect of the rootstock on two important fruit quality parameters, soluble solids content (SSC) and titratable acidity (TA), was studied under both non-saline and saline conditions. Increased SSC and TA in fruits from grafted plants grown under saline conditions were observed on different grafting combinations. One of these rootstocks (cv. Radja) was able to induce increases in both fruit yield and fruit quality traits of the scion. When recombinant inbred lines (RILs) from the crossing of the cultivated tomato and wild tomato (Solanum cheesmaniae) were tested as rootstocks, using the commercial hybrid 'Boludo' as scion, the rootstock also improved SSC and TA when grafted plants were grown under non-saline conditions. On the whole, these results show the effectiveness of grafting with respect to upgrading of fruit quality in tomato, which is of great importance as grafting is a rapid and efficient alternative to achieve this goal.
Nonlinearity, 2004
We prove the existence of periodic orbits with minimal period greater than any prescribed number ... more We prove the existence of periodic orbits with minimal period greater than any prescribed number for a natural Lagrangian autonomous system in several variables that is analytic and periodic in each variable and whose potential is nonconstant.
Nonlinear Analysis: Theory, Methods & Applications, 1996
Nonlinear Analysis: Theory, Methods & Applications, 2008
In this work we consider the following problem
Journal of Differential Equations, 2014
We prove that linear almost periodic systems always carry almost automorphic dynamics, thus confi... more We prove that linear almost periodic systems always carry almost automorphic dynamics, thus confirming in this case a more general conjecture by Shen and Yi. The result is based on the accurate description of the breakdown of the Favard separation condition.
Journal of Differential Equations, 2013
We consider the scalar differential equationu = f (u) + c h(t) where f (u) is a jumping nonlinear... more We consider the scalar differential equationu = f (u) + c h(t) where f (u) is a jumping nonlinearity and h(t) is an almost periodic function, while c is a real parameter deciding the size of the forcing term. The main result is that, if h(t) does not vanish too much in some suitable sense, then the equation admits a (unique) almost periodic solution for large values of the parameter c. The class of the h(t)'s to which the result applies is studied in detail: it includes all the nontrivial trigonometric polynomials and is generic in the Baire sense.
Comptes Rendus Mathematique, 2012
This note is devoted to several inequalities deduced from a special form of the logarithmic Hardy... more This note is devoted to several inequalities deduced from a special form of the logarithmic Hardy-Littlewood-Sobolev, which is well adapted to the characterization of stationary solutions of a Keller-Segel system written in self-similar variables, in case of a subcritical mass. For the corresponding evolution problem, such functional inequalities play an important role for identifying the rate of convergence of the solutions towards the stationary solution with same mass. Hardy-Littlewood-Sobolev inequality; Onofri's inequality; Legendre duality; best constants -MSC (2010): Primary: 26D10; 92C17. Secondary: 35B40
Communications in Partial Differential Equations, 2014
We investigate the large-time behavior of the solutions of the two-dimensional Keller-Segel syste... more We investigate the large-time behavior of the solutions of the two-dimensional Keller-Segel system in self-similar variables, when the total mass is subcritical, that is less than 8 π after a proper adimensionalization. It was known from previous works that all solutions converge to stationary solutions, with exponential rate when the mass is small. Here we remove this restriction and show that the rate of convergence measured in relative entropy is exponential for any mass in the subcritical range, and independent of the mass. The proof relies on symmetrization techniques, which are adapted from a paper of J.I. Diaz, T. Nagai, and J.-M. Rakotoson, and allow us to establish uniform estimates for L p norms of the solution. Exponential convergence is obtained by the mean of a linearization in a space which is defined consistently with relative entropy estimates and in which the linearized evolution operator is self-adjoint. The core of proof relies on several new spectral gap estimates which are of independent interest. R 2 n 0 dx < 8 π , then there exists a solution u, in the sense of distributions, that is global in time and such that M = R 2 u(t, x) dx is conserved along the evolution in the euclidean space R 2 . There is no non-trivial stationary solution of (1.1) and any solution converges to zero locally as time gets large. In order to study the asymptotic behavior of u, it is convenient to work in self-similar variables. We define R(t) := √ 1 + 2 t, τ (t) := log R(t), and the rescaled functions n and c by u(t, x) := R −2 (t) n τ (t), R −1 (t) x and v(t, x) := c τ (t), R −1 (t) x .
Communications in Mathematical Physics, 2010
We study a three dimensional continuous model of gravitating matter rotating at constant angular ... more We study a three dimensional continuous model of gravitating matter rotating at constant angular velocity. In the rotating reference frame, by a finite dimensional reduction, we prove the existence of non radial stationary solutions whose supports are made of an arbitrarily large number of disjoint compact sets, in the low angular velocity and large scale limit. At first order, the solutions behave like point particles, thus making the link with the relative equilibria in N -body dynamics.
Annali di Matematica Pura ed Applicata, 2006
This paper uses topological degree methods to prove the existence of periodic solutions of some q... more This paper uses topological degree methods to prove the existence of periodic solutions of some quaternionic-valued ordinary differential equations.
Buscando seguridad y eficiencia.