( ( The reaction ) ( ( is ( considered ( to ( ( ( ( ( be negative ) ( ( ( if ( ( the ( bovine reaction ) ) ( is negative ) ) ) or ) ( if ( ( the ( bovine reaction ) ) ( is positive ) ) ) ) ) , ) but ) ( ( equal ( to ( or less ) ) ) ( than ( a ( positive ( avian reaction ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN reaction)) (VP (VBZ is) (VP (VBN considered) (S (VP (TO to) (VP (VP (VB be) (ADJP (JJ negative)) (SBAR (SBAR (IN if) (S (NP (DT the) (JJ bovine) (NN reaction)) (VP (VBZ is) (ADJP (JJ negative))))) (CC or) (SBAR (IN if) (S (NP (DT the) (JJ bovine) (NN reaction)) (VP (VBZ is) (ADJP (JJ positive))))))) (, ,) (CC but) (VP (JJ equal) (PP (TO to) (NP (QP (CC or) (JJR less)))) (PP (IN than) (NP (DT a) (JJ positive) (NN avian) (NN reaction))))))))) (. .)))
The reaction is considered to be negative if the bovine reaction is negative or if the bovine reaction is positive, but equal to or less than a positive avian reaction.
(ROOT (S (S (VP (VBZ Is) (NP (NP (DT the) (NN heat)) (PP (IN of) (NP (NP (NN reaction)) (PP (IN for) (NP (DT an) (JJ endothermic) (NN reaction)))))))) (VP (VBZ is) (ADJP (JJ positive))) (. .)))