Each professional employee certified by the State Board of Education and employed by a local or regional board of education who is a member of the reserve corps of any branch of the armed forces of the United States, as defined in section 27-103, shall be entitled to be absent from his or her duties or services while engaged in required field training in such reserve corps. No such employee shall be subjected by any person, directly or indirectly, by reason of such absence, to any loss or reduction of vacation or holiday privileges or be prejudiced by reason of such absence with reference to promotion or continuance in employment or to reemployment. The period of absence in any calendar year shall not exceed thirty days.