Marco Marletta

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In CHO cells we had found that CCK positively regulated cell proliferation via the activation of a soluble guanylate cyclase. Here we demonstrate that CCK stimulated a nitric oxide synthase (NOS) activity. The production of NO was involved in the proliferative response elicited by CCK regarding the inhibitory effect of NOS inhibitors L-NAME and(More)
Starting with an adjoint pair of operators, under suitable abstract versions of standard PDE hypotheses, we consider the Weyl M -function of extensions of the operators. The extensions are determined by abstract boundary conditions and we establish results on the relationship between the M -function as an analytic function of a spectral parameter and the(More)
A shooting method is developed to approximate the eigenvalues and eigenfunctions of a 4th order Sturm-Liouville problem. The main tool is a miss-distance function M(), which counts the number of eigenvalues less than. The method approximates the coeecients of the diierential equation by piecewise-constant functions, which enables an exact solution to be(More)
We describe a new code (SLEUTH) for numerical solution of regular two-point fourth-order Sturm-Liouvlle eigenvalue problems. Eigenvalues are computed according to index: the user specifies an integer <italic>k</italic>***0, and the code computes an approximation to the <italic>k</italic>th eigenvalue. Eigenfunctions are also avialable through an auxiliary(More)
This paper gives the analysis and numerics underlying a shooting method for approximating the eigenvalues of nonselfadjoint Sturm-Liouville problems. We consider even order problems with (equally divided) separated boundary conditions. The method can nd the eigenvalues in a rectangle and in a left half-plane. It combines the argument principle with the(More)
Author’s address: Computational and Applied Mathematics Group, Royal Military College of Science, Shrivenham, Swindon Wilts SN6 8LA, U.K. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the ACM copyright notice and the title of the publication and(More)
1 The general problem class We consider on the interval (−π, π) the singular non-symmetric differential equation Lu := iε d dx f (x) du dx + i du dx = λu, (1.1) in which f is a 2π-periodic function having the following properties: f (x + π) = −f (x) , f (−x) = −f (x) ; (1.2) * We are grateful to Brian Davies for attracting our interest to the problem, and(More)