very useful talk on DM in tamil thogh with some sales pitch;-) forget the sales and listen to the useful knowledge

 I wish he could  develop more such talks without trying to push products.
forget about the sales of the products  listen to the talk it is useful
http://www.bing.com/videos/search?q=dr.ravishankar&qpvt=dr.ravishankar&form=VBLINK