Some of the causes in children for Dark circles under eyes in children may include: 1  Lack of sleep. 2  Nasal congestion. 3  Black eye due to trauma.  Frequent eye 1  rubbing. Hayfever.  Inherited 1  trait. Dehydration. 2  Allergies. 3  Eczema. Phenol sulfotransferase deficiency.
From From P300 Development across the Lifespan: A Systematic Review and Meta-Analysis. The latency and amplitude of the P300 response may vary as a function of age. The P300 (P3) wave is an event related potential (ERP) component elicited in the process of decision making.pplications in brain-computer interfacing (BCI) have also been proposed. The P300 has a number of desirable qualities that aid in implementation of such systems. First, the waveform is consistently detectable and is elicited in response to precise stimuli.
Atrial and ventricular depolarization and repolarization are represented on the ECG as a series of waves: the P wave followed by the QRS complex and the T wave. The first deflection is the P wave associated with right and left atrial depolarization. Wave of atrial repolarization is invisible because of low amplitude. Normal P wave is no more than 2.5 mm (two-and-a half1-mm-divisions) tall and less than 120 ms (three 1-mm-divisions) in width in any lead.