Adrug that enhances positive emotional reactions and minimizes negative ones, like nicotine, is said to have

The answer to this question is adjustive value
adjustive value refers to the effect of drugs that we can cotrol to influence the outcome that we want from our body.
By using caffeine for example, we can control our body response so our brain feel more stimulated and prevent us from being sleepy.

Currently, as of february 2016, an american traveling in france would be by the exchange rate. the weakness of the euro and the strength of the us dollar means that items in france cost less to an american than they otherwise would. of course, if this trend reverses and the us dollar weakens and the euro strengthens, such as was happening in early 2008, an american traveling in france would have an adverse experience because items would cost relatively more.