Students are required to submit a dissertation by the end of the fifth year unless the program director and respective thesis committees approve an extension.  Specific terms and conditions must be set prior to approval of an extension.  Dissertation projects are presented by each student in a formal seminar that is open to the public.  The seminar is followed by a closed oral defense with the student and his/her thesis committee.  The committee will use this time to ask in-depth questions about the thesis research and to ensure the student’s overall scientific proficiency in the field.  Although it is unlikely for students to fail at this point, thesis committees have the option to pass students conditionally if an unequivocal decision is not made.  In such cases, students will only receive their degrees after successful completion of additional requirements determined by the committees.  All students are required to publish at least one primary-author, peer-reviewed journal article or conference proceeding.  Only under rare circumstances will this requirement be excused via unanimous agreement by the thesis committee.