Fermilab developers continue to be hard at work on their Scientific Linux 7.0 OS, which of course is respun from Red Hat Enterprise Linux 7
While Scientific Linux 7.0 Beta 3 comes less than two weeks after the SL 7.0 Beta 2, this latest beta corrects artwork for use on large KDE desktops and most notably works toward UEFI Secure Boot support. Scientific Linux developers are working towards Secure Boot compliance and have joined the UEFI Forum. Updates have been made to SL7's kernel, the GRUB2 bopot-loader, and the unsigned shim, but the stack isn't yet fully signed though it looks like that will happen ahead of the official Scientific Linux 7.0 release.
More details on this popular derivative of Red Hat Enterprise Linux can read about Scientific Linux 7.0 Beta 3 via scientific-linux-devel