This is done with the
Digital Carvers Guild Shader Ops - Although Carrara 5 does have a fresnel thingy* it appears (in my very limited experience) to be limited to the transparency and reflective channels. This was done by adding a "fake fresnel" to the glow channel.
*Yep I really know what I am talking about !
edit-
Here is another slightly higher quality image with the fresnel bit also copied from the glow to the colour channel.
also added the *.car.