The cortical and subcortical circuit regulating both cognition and cardiac autonomic interactions are already well established. This circuit has mainly been analyzed from cortex to heart. Thus, the heart rate variability (HRV) is usually considered a reflection of cortical activity. In this paper, we investigate whether HRV changes affect cortical activity. Short-term local autonomic changes were induced by three breathing strategies: spontaneous (Control), normal (NB) and slow paced breathing (SB). We measured the performance in two cognition domains: executive functions and processing speed. Breathing maneuvres produced three clearly differentiated autonomic states, which preconditioned the cognitive tasks. We found that the SB significantly increased the HRV low frequency (LF) power and lowered the power spectral density (PSD) peak to 0.1[Formula: see text]Hz. Meanwhile, executive function was assessed by the working memory test, whose accuracy significantly improved after SB, with no significant changes in the response times. Processing speed was assessed by a multitasking test. Consistently, the proportion of correct answers (success rate) was the only dependent variable affected by short-term and long-term breath pacing. These findings suggest that accuracy, and not timing of these two cognitive domains would benefit from short-term SB in this study population.

Abstract:In most of microwave heating applications obtaining uniform heating patterns in certain regions of the applicator is a key issue. In this paper, the proposed solution for achieving electric field uniformity consists of designing the configuration of the feeding system in a multimode cavity by means of Genetic Algorithms. The feeding system is constituted by waveguides or slots arrays. The electric field pattern inside the cavity depends on the location of these sources and an improvement in the electric field uniformity on the product can be obtained by means of a proper design of this feeding system. Results for the curing of epoxy resin over a marble slab are presented and they show a significant improvement in the electric field uniformity over the epoxy resin.