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
adifferent date?   Are those processes to be expected?  Should I be concerned?  I'm running on Postgres 8.3.8.  The
databaseis 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