My Macbook Air 2013 13" battery has nearly halved since installing Maverics

I installed the new OS 5 days ago (day after release) and since then my battery life has dropped from around 12-13 hours at 100% to 7-8 hours (as you can see in the screenshot).

MacBook Air

13-inch, Mid 2013 (Haswell)

Processor 1.7 GHz Intel Core i7

Memory 8 GB 1600 MHz DDR3

Graphics Intel HD Graphics 5000 1024 MB

Software OS X 10.9 (13A603)

This is when I use the laptop just for internet browsing.

I have read about this problem on other forums and tried solutions mentioned at https://discussions.apple.com/thread/5466690?start=15&tstart=0

Anyone got any ideas how to sort this out??

Cheers, Stu