Editorial

With great satisfaction, we present the second quarterly issue of the Journal Boliviano de Ciencias for 2018. This edition includes five articles related to the fields of engineering and architecture, contributing to the journal's objective: disseminating scientific knowledge through research processes and promoting technological development in the country. The first article comes from the Department of Architecture and Urbanism, where Rojas analyzes the behavior of concrete when partially replaced with coarse aggregates recycled from demolished concrete. The author also demonstrates its application as structural concrete for housing. The second article, from the Department of Biomedical Engineering, presents the work of Montaño and Quezada, who propose a brain stimulation system to induce relaxation in individuals suffering from stress. To achieve this, the authors develop and implement an analysis system for alpha and beta waves with audiovisual stimulation feedback. The third article originates from the Department of Electromechanics, in collaboration with the Department of Electronics and Telecommunications. In this work, Montaño and Ramos conduct the modeling and simulation of a four-degree-of-freedom robot, providing a detailed explanation of the equations governing its dynamic model.