Juan Francisco Díaz

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The orientational behavior of microtubules assembled in strong magnetic fields has been studied. It is shown that when microtubules are assembled in a magnetic field, they align with their long axis parallel to the magnetic field. The effect of several parameters known to affect the microtubule assembly are investigated with respect to their effect on the(More)
We propose PiCO, a calculus integrating concurrent objects and constraints, as a base for music composition tools. In contrast with calculi such as [5], [9] or TyCO [16], both constraints and objects are primitive notions in PiCO. In PiCO a base object model is extended with constraints by orthogonally adding the notion of constraint system found in the(More)
The epidemiology of tuberculosis remains poorly understood. We investigated the relative importance of within-household and community transmission of infection among children aged 6 months to 14 years living in a Peruvian shanty-town. The prevalence of Mycobacterium tuberculosis exposure among 175 contact children (sharing a household with a person who had(More)
Small-angle x-ray solution scattering (SAXS) is analyzed with a new method to retrieve convergent model structures that fit the scattering profiles. An arbitrary hexagonal packing of several hundred beads containing the problem object is defined. Instead of attempting to compute the Debye formula for all of the possible mass distributions, a genetic(More)
Unconstrained molecular dynamics simulations of the GDP and GTP complexes of Ha-ras p21 protein are performed in aqueous environment for 500 ps, using the GROMOS force field. The solvated structures are mutually compared as well as to the X-ray structures [Tong, L. A., de Vos, A. M., Milburn, M. V., & Kim, S. H. (1991) J. Mol. Biol. 217, 503-516; Pai, E.(More)
The problem of reconfiguring power distribution system to reduce power losses has been extensively studied because of its significant economic impact. A variety of approximation computational models have recently been proposed. We describe a constraint programming model for this problem, using the MOzArt system. To handle real world reconfiguration systems(More)
Here we introduce DePathos, a graphical tool for a time-tabling constraint engine (Pathos). Since the core of Pathos is text-based and provides little user-interaction, finding an appropriate solution for large problems (1000-2000 variables) can be a very time consuming process requiring the constant supervision of a constraint programming expert. DePathos(More)
The conformational change of alpha-chymotrypsin from an inactive, chymotrypsinogen like structure at high pH to an active conformation around pH 8.5 is used here as a model system to generate possible pathways for the transition by use of two different theoretical methods. One method, the 'targeted molecular dynamics' algorithm (TMD) adds a constraint in(More)