Now there's a face only a mother could love. What blows my mind is the size of some of the fossil sharks teeth... so much for the good old days!
Scroll down this page to the green area. You can download a free copy of the NDS commentary. Sections 3.2, 3.4, 4.4.3 deal with notches. Technically you can't notch in the middle third of span of a beam by the NDS.
http://www.awc.org/Publications/download.htmlCode allows holes up to 1/3 depth anywhere as long as they are not closer than 2" to either edge.
Also googling reentrant joist notch or similar will probably yield some more info. That's the fifty cent name of the sharp cornered notch's point of fracture, or where concrete slabs always crack. A smooth transition helps reduce the shear concentration from that one point.
