An earth scientist is sent to another world where instead of objects wearing out as you use them, they improve. For example, swords get sharper when wielded often, baskets get less holes the more things they carry, broaches get shinier the more they are worn. This had certain side-effects such as kings getting servants to make poor objects, use them a lot until they are nearly perfect, and then give them to the king. In this universe there are certain similarities with Lamarck's theory of biological evolution.
Another 40% is made up of Esters with marked relaxing effects on tissues - relieving tension in injured areas and allowing natural perfusion to take place.
To begin with we must distinguish between the two polyunsaturated fatty acids which are termed essential because they can not be made in the body and therefore must be present in the diet.
Different procedures practiced in yoga have stimulatory or inhibitory effects on the basal metabolic rate when studied.
So when you average the difference scores, the practiceeffect disappears and you are left with the treatment effect, provided the two groups have the same number of subjects.
For example, if the practiceeffect is about the same size as the treatment effect, one set of difference scores will be around zero, and the other will tend to be twice as large as the treatment effect.
Any practiceeffect should be the same for both groups, so it disappears when you calculate the change in the experimental group minus the change in the control group.