Nonconscious control of fundamental voice frequency

The aim of this paper is to answer the question whether "perception-action" dissociation, which is well documented in vision, may also be found in auditory information processing. Trained singers were asked to produce vowel sounds into a microphone. The sound that each singer produced was fed back to their ears via headphones. Two seconds after the sound production had begun, the auditory feedback was shifted in pitch by a certain degree (9, 19, 50, or 99 cents in either direction). In every set of sounds, instances without any pitch shifts also appeared. After each trial, participants reported whether they were aware of a pitch change or not. It was found that even though the participants were unaware of subtle pitch changes, the fundamental frequency of their vowel production was found to shift slightly in the opposite direction to the pitch shift. These results show that auditory information is processed by two separate systems: one for perception and one for action. They also show that the function of the auditory control system differs from the visual control system. The latter is used to control bodily movements while the function of the former is a nonconscious, instant control of vocalization.     

Mass spectra of aminoacyl adenylate pentacoordinated phosphorus compounds

Aminoacyl adenylate pentacoordinated phosphorus compounds were analyzed by field desorption (FD) and fast atom bombardment (FAB) mass spectrometries, together with the B/E linked scan technique, and their mass spectral fragmentation pathways were investigated. For the five bonds (one P-N bond, three P-O bonds and one mixed anhydride bond P-O-CO), the cleavage usually occurred more on the P-N bond, the mixed anhydride bond and the O-C bond adjacent to the P-O bond, and less on the P-O bond. Ion YH(+), corresponding to water loss from protonated 2',3'-O-isopropylidene-adenosine, was the base peak. The results reflect the structural characteristics of aminoacyl adenylate pentacoordinated phosphorus compounds. Copyright 1999 John Wiley & Sons, Ltd.