The work on a dissertation is commonly carried out during a postgraduate study period called "aspirantura". It is performed either within an educational institution (such as a university) or a scientific research institution (such as an institute of the Russian Academy of Sciences network). It can also be carried out without a direct connection to the academy. In exceptional cases, the Candidate of Sciences degree may be awarded on the basis of published scholarly works without writing a thesis. In experimental sciences the dissertation is based on an independent research project conducted under the supervision of a professor, the results of which must be published in at least three papers in peer-review scientific journals.