Ruben A. Romero

Learn More
The P3(00) event-related brain potential (ERP) was elicited with auditory and visual stimuli using an oddball task in which the subject indicated with a button-press response the occurrence of a target stimulus that occurred randomly on 20% of the trials and refrained from responding to a standard stimulus. A total of four trial blocks were collected for(More)
Vasculitis with predominant renalinvolvement are increasingly observed inelderly patients. It predominantly involvespatients with microscopic polyangiitis,Wegener's granulomatosis, renal limitedvasculitis and, in a smaller proportion, ChurgStrauss syndrome.The elderly patients present very fewobvious symptoms or signs of vasculitis such ashemoptysis and(More)
This paper presents a mixed-integer quadratically-constrained programming (MIQCP) model to solve the distribution system expansion planning (DSEP) problem. The DSEP model considers the construction/ reinforcement of substations, the construction/reconductoring of circuits, the allocation of fixed capacitors banks and the radial topology modification. As the(More)
This paper presents a novel mathematical model for the transmission network expansion planning problem. Main idea is to consider phase-shifter (PS) transformers as a new element of the transmission system expansion together with other traditional components such as transmission lines and conventional transformers. In this way, PS are added in order to(More)
BACKGROUND Collecting duct carcinoma of the kidney (CDC) is a rare cancer associated with bad prognosis and, at present, with no specific effective therapies. CASE REPORT We report a clinical case with disseminated highgrade CDC presenting with widespread metastasis to both lungs, pelvic bones, axial skeleton, and the central nervous system (posterior(More)
This paper presents a genetic algorithm for solving the optimal transmission network applied to the expansion planning of Colombia’s system. Main improvements have been introduced in the genetic algorithm: initial population is obtained by constructive heuristic methods of optimization, and elitism and building block concepts are used in the optimization(More)
It has become more evident that in complex problems the performance of a genetic algorithm depends on the initial population, specially on its quality and diversity. In this paper four strategies are presented which, used concurrently allow to find quality and diversified topologies to set up an initial population to be used in a genetic algorithm to solve(More)