add a version of the plot with N_A=0

Closes #53 (closed).

enabled an automatic merge when the pipeline for 63a92611 succeeds

aborted the automatic merge because source branch was updated

added 3 commits

• 63a92611...2c1d5175 - 2 commits from branch master
• 7ede95a4 - add a version of the plot with N_A=0

Compare with previous version

merged