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Noise and Vibrations in the Environment
Published in Gaetano Licitra, Giovanni d'Amore, Mauro Magnoni, Physical Agents in the Environment and Workplace, 2018
Jose Luis Cueto, Luca Fredianelli, Gaetano Licitra, Diego Palazzuoli
In the propagation path, sound waves encounter anomalies to an ideal homogeneous propagation medium. This can happen due to progressive changes in the acoustic impedance of the atmosphere or when an acoustic wave meets walls, the ground or any other object that causes abrupt changes in sound impedance. If there is a noise barrier, such as a wall, the noise energy received is partially absorbed by the barrier and partly reflected off its surface, whilst the remaining energy crosses the barrier and is transmitted again. In the case of very reflective surfaces, noise reflections can cause an increase in the noise level near the barrier. Also, as a consequence of the refraction in the atmosphere, the wave train can overcome obstacles; that is why it is usual to have higher levels than expected behind barriers.
Charles LeMoyne Hospital, Montreal, Canada
Published in William Y. Song, Kari Tanderup, Bradley R. Pieters, Emerging Technologies in Brachytherapy, 2017
Marjory Jolicoeur, Talar Derashodian, Marie Lynn Racine, Georges Wakil, Thu Van Nguyen, Maryse Mondat
One important consideration was the fact that our afterloader was not MRI-compatible. Therefore, in order to deliver treatment in the MRI room, we had to conceal the magnet behind special doors, which not only splits the room but also serve as a noise barrier. Furthermore, operating MRI scanners and interpreting the images requires either additional personnel or expertise. The choice was made to provide training to RTTs and medical physicists in MRI technology. This turned out to be a sensible choice because we now have highly skilled RTTs. Nevertheless, adoption of MRI-guided IGBT may place additional pressure on the number of patients treated in the brachytherapy suite because of the additional time it takes to acquire images compared to conventional IGBT. Since the intent was to have a pace of four to five patients per day at maturity, we had to be creative in mapping the process, optimizing each imaging device at each step for maximum patient throughput (Figure 22.3).
Feasibility of event-related potential (ERP) biomarker use to study effects of mother’s voice exposure on speech sound differentiation of preterm infants
Published in Developmental Neuropsychology, 2018
Olena D. Chorna, Ellyn L. Hamm, Hemang Shrivastava, Nathalie L. Maitre
The sound environment of the NICU for preterm infants is noisy and unnatural, leading to concerns for how it may alter the development of speech sound processing in the immature brain. The importance of the auditory environment was demonstrated using ERP measurement of speech sound contrasts in rodents with Rett syndrome: while they had typical speech sound processing measures in a quiet environment, 3 weeks of training improved their abilities in a noisy environment (Engineer et al., 2015). The sound environment during ERP testing is therefore important to consider in studies of preterm infants (Engineer et al., 2015). Of the participants in our study, 45% were on CPAP, an air pressure support system that in combination with environmental noise can vary between 46 and 75 dB (A) at infant’s ear (Hamm, Chorna, Thomas, Sowers, & Maitre, 2017). It is encouraging to consider, based on our results and previous studies (Friedman & Choudhury, 2005; Lovio et al., 2012; Santos et al., 2007; Yoder et al., 2013), that speech sound training interventions and ERP’s capacity to measure speech sound differentiation seem to overcome the noise barrier, even generated by CPAP.