This is the series of blocks Amino acid substitution matrices (BLOSUM), all of which are derived based on direct on direct observation for every possible amino acid substitution in multiple sequence alignments.
A volt-ampere (VA) is the unit used for the apparent power in an electrical circuit, equal to the product of root-mean-square (RMS) voltage and RMS current.[1] In direct current (DC) circuits, this product is equal to the real power (active power) [2] in watts.
VA = Watts (DC current). In AC if the volts and amps are in phase (for example a resistive load) then the equation is also. VA=Watts (resistive load) where V is the RMS voltage and A the RMS amperage. In AC, the volts and amps are not always in phase (meaning that the peak of the voltage curve is does not happen at the peak of the current curve). Think of pushing a swing. The greatest force is applied when the swing stops at the peak, but the greatest velocity is at the bottom of the arc.