A Power-Line Communication System Governed by Loop Resonance for Photovoltaic Plant Monitoring.

Within this paper, a PLC system that takes advantage of the loop resonance of an entire DC-PV string configured as a circular signal path is developed and implemented. Low cost and extremely simple transceivers intended to be installed within each PV module of a string have been designed and successfully tested. In addition, an anti-saturation coil has been conceived to avoid saturation of the core when the entire DC current of the string flows through it. Bi-directional half-duplex communication was successfully executed with up to a 1 MHz carrier frequency (150 kbps bitrate), using a simple ASK modulation scheme. The transmission and reception performance are presented, along with the overall system cost in comparison to the previous literature.

Can decision-making skills affect responses to psychological stress in healthy women?

In recent studies showing how stress can affect an individual's decision-making process, the cognitive component of decision-making could also be considered a coping resource available to individuals when faced with a stressful situation. The Iowa Gambling Task (IGT) constitutes the standard test for the assessment of decision-making skills under conditions of uncertainty. Responses of the hypothalamic-pituitary-adrenal (HPA) axis to psychosocial stress, in turn, have been estimated by means of cortisol measurements. Our main objective in this study was to test if good and bad IGT performers show distinct HPA axis responses, when challenged in a classic psychosocial stress test. Because women have been shown to outperform men on the IGT under the influence of psychosocial stress, we chose a sample of 40 women to take the IGT before they were exposed to a public speaking task in a virtual environment. The activation of the HPA axis, involved in the stress response, was assessed by examining the levels of cortisol in the subjects' saliva at the following four stages: before the challenge, after the challenge, and 10 and 20 min after the task. Participants were divided into two groups according to their level of performance, good or poor, on the IGT. Results showed statistically significant differences between the groups for pre-exposure cortisol levels and for cortisol levels 20 min after exposure. Overall cortisol levels were significantly higher in the group with poor performance on the IGT. It appears that good decision-making, which may be an important resource for coping with stress, is associated with a lower HPA axis response to a psychosocial stressor.