????? ???? ??? ?????? ??????? ?? ?????? . ??? ???? ?????? ??????? ?? ??????. ???? ????????? ??????? ??????? ??????? ?? ????????? , ? ???? ????????? ???? ???? ???????. ????? ???? ??? ? ????? ???? ???? ??????? ?????? ???? ?? ??????????? ???? {????? ????? ????? ???????? ???? ??????? ???? ???? ??? ????? ??????. fluctuations ????? ??????? ??