Index is not used

Hi,

I am using pgsql 7.3.4 on rh7.3.

I have a table and an index on it. The index is used when i use '='
operator for the indexed field in the where condition. But the index is
not used when i use '>=' operator for the same field. Herewith i have
attached the explain output. Hope to get some lights.

regards,
bhuvaneswaran