???, ??????? ?????????? ???? ?????????????? ???????? ??? ???????????? ?????? ????????? ?????????? ????? ????????? ??????, ????????????? ?????? ??????? ???, ????? ???? ?????????? study observed ??? ?????????? ????????? ?????????????????? ????? ???????????? ?????????? ??????? ??? ??????????????? ??? ???????? ???????????????? ???? ?????????? 2 ??????