We have added several packages to Scientific Linux 5.3 that were not in the Scientific Linux 5.2 release.

aufs
Summary: Aufs is a stackable unification filesystem such as Unionfs, which unifies several directories and provides a merged single directory. Aufs is an entirely re-designed and re-implemented Unionfs
This is not installed by default.

fftw
Summary: FFTW is a C subroutine library for computing the Discrete Fourier Transform (DFT) in one or more dimensions.
This is not installed by default.

iwlwifi-3945-ucode
iwlwifi-5000-ucode
Summary: Firmware (ucode) for Intel wireless
These are installed by default.

nedit - Provided by vendor
Summary: Nedit is now provided by The Upstream Vendor. So it is no longer "added" but merely part of the release.

scipy
Summary: The SciPy library is built to work with NumPy arrays, and provides many user-friendly and efficient numerical routines such as routines for numerical integration and optimization.
This is not installed by default.

suitesparse
Summary: suitesparse is a collection of libraries for computations involving sparse matrices.
This is not installed by default.

yum-cron
Summary: yum-cron has a different cron script than is provided in yum-autoupdate.
This are not installed by default.