Romer Endogenous Growth Model

Here is my lecture on Endogenous Growth. Unfortunately for some parts of the video there are sound quality issues, not sure why. The problem seemed to correct itself by the end of the video. It may have had something to do with a matlab program I was running in the background.

[terenceyhip]

Some points need covering;
1) Are the Romer production functions (final goods & intermediate goods) exhibit constant returns or increasing returns to scale
2) The scale effect of big population and hence big pool of talent needs qualification given the decline in US productivity growth and its absolute size of talent (see Charles Jones' comment)
Comments please?

[avavaviv]

How can ideas be destroyed with capital decumulation? Isn't this just a complicated way of introducing positive returns to scale?

[Generalupdate]

At the video on 1:04:25, I could not satisfy, please explain it

[christophertamina]

At 32;16 you say that the only input factors that enters the fi al good production function are the intermediate goods; So you nean to say that labour is not used by firns in tbe final sector? Then yiu say that labour is the only input used by firms i. The intermediate sector? Nothing is produced in the intermediate sector. It is a arket point where R&D and final sectors meet for exchange. R and D sector selks patents ti final sector. Lavour is used i. R and D and final sectors only! Correct me if I am wrong