Don't' Understand the Processes Listing Associated with Postgres

Hi,

I'm looking at all the processes from 'ps' that are related to Postgres. How come there is a process associated with a different date? Are those processes to be expected? Should I be concerned? I'm running on Postgres 8.3.8. The database is working and running.

Here is the list:
1 S postgres 13599 13596 0 75 0 - 9003 schedu May06 ? 00:17:25 postgres: writer process
1 S postgres 13600 13596 0 75 0 - 8971 schedu May06 ? 00:10:57 postgres: wal writer process
1 S postgres 13601 13596 0 75 0 - 9038 schedu May06 ? 00:04:04 postgres: autovacuum launcher process
1 S postgres 13602 13596 0 75 0 - 1873 schedu May06 ? 00:04:16 postgres: stats collector process
1 S postgres 11416 13596 0 75 0 - 9434 schedu May25 ? 00:00:13 postgres: postgres marydatabase 127.0.0.1(35333) idle
1 S postgres 7462 13596 0 75 0 - 9404 schedu May26 ? 00:00:14 postgres: postgres marydatabase 127.0.0.1(35465) idle
1 S postgres 7464 13596 0 75 0 - 9455 schedu May26 ? 00:00:23 postgres: postgres marydatabase 127.0.0.1(35466) idle
1 S postgres 7107 13596 0 75 0 - 9424 schedu May27 ? 00:00:05 postgres: postgres marydatabase 127.0.0.1(35801) idle
1 S postgres 7108 13596 0 75 0 - 9431 schedu May27 ? 00:00:19 postgres: postgres marydatabase 127.0.0.1(35802) idle
1 S postgres 16224 13596 0 75 0 - 9438 schedu May28 ? 00:00:07 postgres: postgres marydatabase 127.0.0.1(36292) idle
1 S postgres 16234 13596 0 75 0 - 9445 schedu May28 ? 00:00:12 postgres: postgres marydatabase 127.0.0.1(36293) idle
1 S postgres 18301 13596 0 75 0 - 9448 schedu May29 ? 00:00:04 postgres: postgres marydatabase 127.0.0.1(36676) idle
1 S postgres 17034 13596 0 75 0 - 9442 schedu May30 ? 00:00:09 postgres: postgres marydatabase 127.0.0.1(37498) idle
1 S postgres 21184 13596 0 75 0 - 9392 schedu Jun01 ? 00:00:01 postgres: postgres marydatabase 127.0.0.1(38322) idle

Thanks
Mary