Auditory-Motor Adaptation to Frequency-Altered Auditory Feedback Occurs When Participants Ignore Feedback

Background Auditory feedback is important for accurate control of voice fundamental frequency (F0). The purpose of this study was to address whether task instructions could influence the compensatory responding and sensorimotor adaptation that has been previously found when participants are presented with a series of frequency-altered feedback (FAF) trials. Trained singers and musically untrained participants (nonsingers) were informed that their auditory feedback would be manipulated in pitch while they sang the target vowel [/ɑ /]. Participants were instructed to either ‘compensate’ for, or ‘ignore’ the changes in auditory feedback. Whole utterance auditory feedback manipulations were either gradually presented (‘ramp’) in -2 cent increments down to -100 cents (1 semitone) or were suddenly (’constant‘) shifted down by 1 semitone. Results Results indicated that singers and nonsingers could not suppress their compensatory responses to FAF, nor could they reduce the sensorimotor adaptation observed during both the ramp and constant FAF trials. Conclusions Compared to previous research, these data suggest that musical training is effective in suppressing compensatory responses only when FAF occurs after vocal onset (500-2500 ms). Moreover, our data suggest that compensation and adaptation are automatic and are influenced little by conscious control

Self-Management of Type 1 Diabetes Across Adolescence: A Dissertation

Little is known about what variables affect self-management practices of adolescents with T1D. Few studies have examined differences in self-management behaviors by stage of adolescence. Similarly, no studies have examined all of the attributes of self-management, including Collaboration with Parents and Goals. In order to fill the gaps in the literature, a secondary data analysis with a descriptive correlation design was conducted to describe T1D self-management behaviors (Collaboration with Parents, Diabetes Care Activities, Diabetes Problem Solving, Diabetes Communication and Goals) during early, middle and late stages of adolescence. This study also examined whether the roles of covariates (regimen, duration of illness (DOI), gender) in self-management behaviors vary by stage of adolescence. Data from 504 subjects aged 13 – 21 years were analyzed and the age variable was transformed into three adolescent stages early (13-14) (n=163), middle (15-16) (n=159) and late (17-21) (n=182). The findings revealed significant differences between adolescent stages on Collaboration with Parents and the Diabetes Problem Solving subscale. The covariate analysis showed no significant effect modification for the covariates and stage on any of the subscales so the results did not differ from the ANOVA model. Covariate analysis showed significant associations between regimen and Collaboration with Parents, Diabetes Care Activities and Diabetes Problem Solving. DOI showed significant associations only with Diabetes Problem solving and gender had significant associations with Diabetes Care Activities and Diabetes Communication. The mean scores on Collaboration with Parents show an incremental decline in collaboration with parents as adolescents move through stages. The higher mean Diabetes Problem Solving scores found in the late adolescent group compared correlated with a higher degree of problem solving in this group when compared to those in the early or middle adolescent stage group. Regimen had significant associations with three of the five subscales suggesting this is an important variable for future study. DOI did not have a significant impact on self-management whereas gender related differences in the areas of Diabetes Activities and Diabetes communication warrant further investigation

Concrete Beam Design Optimization with Genetic Algorithms

This paper demonstrates an application of the natural selection process to the design of structural members. Reinforced concrete beam design is used as the example to show how various chromosomes representing a design solution can be formulated. Fitter chromosomes (or better solutions) have a better chance of being selected for cross over; this in turn creates better generations. Random mutation is used to enhance the diversity of the population. The evolution progresses through several generations, and the best solution is then used in the design. The method gives reasonable results, but sometimes a local (as opposed to the global) optimized solution is obtained

Hiram Johnson : his part in isolation in the 1930's

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The Sensitivity of Auditory-Motor Representations to Subtle Changes in Auditory Feedback While Singing

Singing requires accurate control of the fundamental frequency (F0) of the voice. This study examined trained singers’ and untrained singers’ (nonsingers’) sensitivity to subtle manipulations in auditory feedback and the subsequent effect on the mapping between F0 feedback and vocal control. Participants produced the consonant-vowel /ta/ while receiving auditory feedback that was shifted up and down in frequency. Results showed that singers and nonsingers compensated to a similar degree when presented with frequency-altered feedback (FAF); however, singers’ F0 values were consistently closer to the intended pitch target. Moreover, singers initiated their compensatory responses when auditory feedback was shifted up or down 6 cents or more, compared to nonsingers who began compensating when feedback was shifted up 26 cents and down 22 cents. Additionally, examination of the first 50 ms of vocalization indicated that participants commenced subsequent vocal utterances, during FAF, near the F0 value on previous shift trials. Interestingly, nonsingers commenced F0 productions below the pitch target and increased their F0 until they matched the note. Thus, singers and nonsingers rely on an internal model to regulate voice F0, but singers’ models appear to be more sensitive in response to subtle discrepancies in auditory feedback