Lateral Circuitry Research Articles

A Comprehensive Analysis of Partial Shading Effect on Output Parameters of a Grid-connected PV System

One of the issues of grid-connected photovoltaic systems is the effect of the partial shading on the key parameters and performance of the system. In practice, a share of the entire PV panel may shadded because of the various reasons, inevitably. In this case, the key parameters of the system output are affected with respect to the shading extent and paradigm. In this paper, the effects of the various partial shading patterns on the ouput of the system are examined. This is performed by deriving relevant equations and appropriate modeling of the system and defining different scenarios. The analysis on the system performance is carried out on the dominant output parameters including panel voltage, panel power, and total harmonic distortion (THD) of the inverter. Also, the study considers the effect of using bypass diodes in the panels or not. Addintionally, to compare derived conclusions, the study is implementd on a practical system. The set up is made up of a 7-level multi-level inverter, a Z-source converter, and 1 kW lateral circuitry. The real world test results of the study demonstrate a negligible deviation compared to the simulation results.

The Functional Networks of Prepulse Inhibition: Neuronal Connectivity Analysis Based on FDG-PET in Awake and Unrestrained Rats.

Prepulse inhibition (PPI) is a neuropsychological process during which a weak sensory stimulus (“prepulse”) attenuates the motor response (“startle reaction”) to a subsequent strong startling stimulus. It is measured as a surrogate marker of sensorimotor gating in patients suffering from neuropsychological diseases such as schizophrenia, as well as in corresponding animal models. A variety of studies has shown that PPI of the acoustical startle reaction comprises three brain circuitries for: (i) startle mediation, (ii) PPI mediation, and (iii) modulation of PPI mediation. While anatomical connections and information flow in the startle and PPI mediation pathways are well known, spatial and temporal interactions of the numerous regions involved in PPI modulation are incompletely understood. We therefore combined [18F]fluoro-2-deoxyglucose positron-emission-tomography (FDG-PET) with PPI and resting state control paradigms in awake rats. A battery of subtractive, correlative as well as seed-based functional connectivity analyses revealed a default mode-like network (DMN) active during resting state only. Furthermore, two functional networks were observed during PPI: Metabolic activity in the lateral circuitry was positively correlated with PPI effectiveness and involved the auditory system and emotional regions. The medial network was negatively correlated with PPI effectiveness, i.e., associated with startle, and recruited a spatial/cognitive network. Our study provides evidence for two distinct neuronal networks, whose continuous interplay determines PPI effectiveness in rats, probably by either protecting the prepulse or facilitating startle processing. Discovering similar networks affected in neuropsychological disorders may help to better understand mechanisms of sensorimotor gating deficits and provide new perspectives for therapeutic strategies.

Early modulation of visual cortex by sound: an MEG study

Sound can alter visual perception. This has been recently demonstrated by a strong illusion in which a single flash is perceived as multiple flashes when accompanied by multiple brief sounds. While psychophysical findings on this sound-induced flash illusion indicate that the modulations of visual percept by sound occur at a perceptual processing level, it remains unclear at what level of perceptual processing these interactions occur and what mechanisms mediate them. Here we investigated these questions using MEG. We found modulation of activity in occipital and parietal scalp locations, when comparing illusion trials with visual-alone and auditory-alone trials. This modulation occurred as early as 35–65 ms from the onset of the visual stimulus. Activity was also modulated in the occipital and parietal areas as well as anterior areas at a later (∼150 ms post-stimulus) onset. No significant interactions were observed in occipital and parietal areas in trials in which illusion was not perceived. These results indicate that the auditory alteration of visual perception as reflected by the illusion is associated with modulation of activity in visual cortex. The early onset of these modulations suggests that a feed-forward or lateral circuitry is at least partially involved in these interactions.