The introduction of a pleasant stimulus is to as the withdrawal of a pleasant stimulus is to

The introduction of a pleasant stimulus is to "reinforcement" as the withdrawal of a pleasant stimulus is to "punishment".

Positive or pleasant and negative or aversive are the two types of consequences of stimulus. These can be added to or detracted from the earth to change the likelihood of a given reaction happening once more.An undesired or improper target conduct will be trailed by evacuation of a positive/pleasant stimulus or the expansion of a negative/aversive stimulus. 

It should be at the center of any map going vertically: the prime meridian, as it passes through greenwich,  england, is considered 0 degrees longitude