B. Cano

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In this paper we develop a technique for avoiding the order reduction caused by nonconstant boundary conditions in the methods called splitting , alternating direction or, more generally, fractional step methods. Such methods can be viewed as the combination of a semidiscrete in time procedure with a special type of additive Runge–Kutta method, which is(More)
In this paper we deal with several issues concerning variable-stepsize linear multistep methods. First, we prove their stability when their fixed-stepsize counterparts are stable and under mild conditions on the step-sizes and the variable coefficients. Then we prove asymptotic expansions on the considered tolerance for the global error committed. Using(More)
Two model problems for stii oscillatory systems are introduced. Both comprise a linear superposition of N 1 harmonic oscillators used as a forcing term for a scalar ODE. In the rst case the initial conditions are chosen so that the forcing term approximates a delta function as N ! 1 and in the second case so that it approximates white noise. In both cases(More)
Some previous works show that symmetric fixed-and variable-stepsize linear multistep methods for second-order systems which do not have any parasitic root in their first characteristic polynomial give rise to a slow error growth with time when integrating reversible systems. In this paper, we give a technique to construct variable-stepsize symmetric methods(More)
  • I Alonso-Mallo, B Cano, M J Moreta
  • 2006
In this paper, a general and detailed study of linear stability of Runge–Kutta–Nyström (RKN) methods is given. In the case that arbitrarily stiff problems are integrated, we establish a condition that RKN methods must satisfy so that a uniform bound for stability can be achieved. This condition is not satisfied by any method in the literature. Therefore, a(More)
Two model problems for stii oscillatory systems are introduced. Both comprise a linear superposition of N 1 harmonic oscillators used as a forcing term for a scalar ODE. In the rst case the initial conditions are chosen so that the forcing term approximates a delta function as N ! 1 and in the second case so that it approximates white noise. In both cases(More)
BACKGROUND We developed a study using low dose radioactive iodine creating an animal model of transient elevation of thyroid stimulating hormone (TSH). Male derived bone marrow cells were transplanted to asses their effect on thyroid function and their capability to repair the thyroid parenchyma. RESULTS At 40 an 80 days after I131 treatment, the study(More)