Well, Our brain uses 13Hz (high alpha or low beta) for "active" intelligence. Often we find individuals who exhibit learning disabilities and attention problems having a deficiency of 13Hz activity in certain brain regions that affects the ability to easily perform sequencing tasks and math calculations.
The lowest frequencies are delta. These are less than 4 Hz and occur in deep sleep and in some abnormal processes. It is the dominant rhythm in infants up to one year of age and it is present in stages 3 and 4 of sleep. It tends to be the highest in amplitude and the slowest waves. We increase Delta waves in order to decrease our awareness of the physical world. We also access information in our unconscious mind through Delta. Peak performers decrease Delta waves when high focus and peak performance are required. However, most individuals diagnosed with Attention Deficit Disorder, naturally increase rather than decrease Delta activity when trying to focus. The inappropriate Delta response often severely restricts the ability to focus and maintain attention. It is as if the brain is locked into a perpetual drowsy state.Another way to look at Delta is to imagine you are driving in a car and you shift into 1st gear....you're not going to get anywhere very fast. So Delta would represent 1st gear.
Alpha, Bravo, Charlie and Delta are the letters of the police alphabet. e.g. Alpha=A Bravo=B
Chi Alpha Delta was created on 1929-04-05.
Delta Kappa Alpha was created on 1936-03-16.
The motto of Alpha Phi Delta is 'Faciamus'.
Alpha Delta Theta was created in 1919.
Alpha Delta Chi's motto is 'As in a Mirror'.
Alpha Lambda Delta was created in 1924.
Phi Alpha Delta was created on 1902-11-08.
Alpha Delta Gamma was created on 1924-10-10.
Delta Kappa Alpha's motto is 'Truth in Illusion'.
Sigma Delta Alpha was created on 1992-05-05.
Alpha Delta Pi was created on 1851-05-15.