( ( ( The rate ) ( ( at which ) ( ( this energy ) ( is released ) ) ) ) ( ( is ( proportional ( to ( ( ( the ( Kelvin temperature ) ) ( -LRB- ( T -RRB- ) ) ) ( raised ( to ( the ( fourth power ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN rate)) (SBAR (WHPP (IN at) (WHNP (WDT which))) (S (NP (DT this) (NN energy)) (VP (VBZ is) (VP (VBN released)))))) (VP (VBZ is) (ADJP (JJ proportional) (PP (TO to) (NP (NP (DT the) (JJ Kelvin) (NN temperature)) (PRN (-LRB- -LRB-) (NP (NNP T)) (-RRB- -RRB-)) (VP (VBN raised) (PP (TO to) (NP (DT the) (JJ fourth) (NN power)))))))) (. .)))
The rate at which this energy is released is proportional to the Kelvin temperature (T) raised to the fourth power.
(ROOT (S (NP (NP (DT The) (NN rate)) (SBAR (IN that) (S (NP (NN energy)) (VP (VBZ is) (VP (VBN released)))))) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (NN power))))) (. .)))