A. M. Vidal

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Previous models of reversible catch in echinoid spines, as a property of muscle or of collagen, are briefly reviewed and discussed. This brief review offers a new interpretation of catch in primary spines of Eucidaris tribuloides, viewing the collagen and small muscles of the catch ligament working together as a variable-length tendon. In the model(More)
This paper describes the parallelization of a method (proposed by Chu in [7]) to solve the Inverse Additive Singular Value Problem (IASVP). The IASVP is a problem whose solution requires a high computational cost, both in time and in memory. For example, the complexity of Chu’s method is O(n) in time and O(n) in memory. Using parallel computing, the time(More)
1. This paper describes the effects of several cholinergic agonists and antagonists, and of beta-phenylethylamine (PEA) and some of its derivatives, on the articular capsule, or ligament, of the primary spines of Eucidaris tribuloides. 2. Carbamylcholine (CCh), methacholine (MeACh), nicotine, and muscarine exert a stiffening effect similar to that of(More)
In this paper we study the different approaches used so far to apply the bisection method for solving the symmetric tridiagonal eigenproblem. We review the sequential methods used to perform the final extraction of the eigenvalues and compare two new techniques that offer very good results. The sequential version of the bisection method we have implemented(More)
1. The articular capsule or ligament, of the primary spines of the sea-urchin Eucidaris tribuloides behaves as a classical excitable tissue, responding with a shortening or contracture to a variety of stimuli including the cholinergic agonists acetylcholine (ACh), methacholine (MeACh), carbamylcholine (CCh) and nicotine. 2. d-Tubocurarine failed to decrease(More)
Many algorithms exist that exploit the special structure of Toeplitz matrices for solving linear systems. Nevertheless, these algorithms suffer from a loss of accuracy or they even can be unstable if the Toeplitz matrix is not strongly regular. It can be found algorithms in the bibliography that overcome this problem of accuracy and stability but it is very(More)
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