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Published in Ken Addley, MCQs, MEQs and OSPEs in Occupational Medicine, 2023
Measurement of environmental noise level. It allows quick sound-level checks of machinery noise, office noise and other issues around the workplace to be carried out. It measures the instantaneous sound level with either A- or C-weighting. Most noise regulations require A-weighting. It also has both fast and slow time response. The device needs regular calibration, and depending on the device will have a range of 30 dB (A) to 130 dB (A) or 40 dB (C) to 130 dB (C). The unit of acoustic measurement for sound is usually the decibel (dB); however, some sound-level meter devices also determine the equivalent continuous sound level (Leq) and other acoustic parameters.
Fetal Physical Parameters
Published in Sujoy K. Guba, Bioengineering in Reproductive Medicine, 2020
Even so the performance was far below expectations. Most of the energy of the fetal heart sound is in the frequency range 75 to 105 Hz.6 Although special microphones do cover this range, the coupling with the body is never good. Environmental noise is readily picked up. After amplification it is difficult to identify the heart sound from the milieu of sounds which includes the noise component. Since the bandwidth of the heart sound and the other sounds overlap, frequency selective filtering does not help significantly.
Quality Assurance, Elimination of Artifacts, and Repeatability
Published in Noam Gavriely, David W. Cugell, Breath Sounds Methodology, 2019
Intermittent contaminating noises are much more difficult to deal with than continuous or periodic repetitive sounds. The most direct and effective method is to identify those sections of recorded sound with significant noise and exclude them from analysis. This may be done by auditory monitoring, which is best if carried out during the initial sound pickup and always before any further processing is performed. An alternative method is the use of a separate ambient noise microphone to monitor environmental noise magnitude. When a noise greater than some preset level is detected by this microphone, sound pickup by the breath sounds sensors is turned off for as long as the environmental noise exceeds the specified threshold. This can be done by an analog gating circuit coupled to a sound-level meter, but can also be done digitally if both chest sensor and ambient noise signals are converted to digital form (Figure 11.2).
Effects of prolonged night-time light exposure and traffic noise on the behavior and body temperature rhythmicity of the wild desert rodent, Gerbillus tarabuli
Published in Chronobiology International, 2021
Salem Mamoun Issad, Nadir Benhafri, Khalid El Allali, Hicham Farsi, Saliha Ouali-Hassenaoui, Aicha Dekar-Madoui
In addition to light pollution, anthropogenic noise represents another significant environmental stressor (Kim 2007) with physiological, behavioral, and health disturbances (Swaddle et al. 2015). Traffic noise primarily emanates from road traffic, railways, and aircraft, and they are the main contributors to the overall burden of environmental noise. Beyond its auditory impact on health, like hearing loss, noise stress has extra-auditory effects on the physiology and behavior of animals. It has been shown that environmental noise exposure can induce changes in DNA methylation in the brain (Guo et al. 2017) and alteration of neurotransmitter levels (Ravindran et al. 2005). Moreover, prenatal exposure to noise stress leads to impaired spatial memory that persists into postnatal life (Barzegar et al. 2015). Also, rats exposed to noise stress develop anxiety and depression-like behavior (Haider 2012). Most studies have examined these impacts separately, and to our knowledge, they have never investigated the combined simultaneous effects of prolonged exposure to anthropogenic noise and light pollution (PEL) on the circadian physiology and behavior in mammals.
An automated magnetoencephalographic data cleaning algorithm
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Antonietta Sorriso, Pierpaolo Sorrentino, Rosaria Rucco, Laura Mandolesi, Giampaolo Ferraioli, Stefano Franceschini, Michele Ambrosanio, Fabio Baselice
The environmental noise is due to unavoidable sources such as trains, cars, portable phones, power lines, elevators, and so on. Several countermeasures can be adopted for limiting such a kind of noise. A magnetically shielded room, a chamber enveloped by layers of aluminum and mu-metal, can attenuate external fields by 100 dB and more (Kawakatsu 2003). The adoption of gradiometer sensors, i.e. two or more coils measuring the differential field, makes the system insensitive to homogeneous magnetic fields which are typical of far (noise) sources. Hence, only nearby signal sources are detected, i.e. those within the brain. Several MEG systems have some reference sensors outside the helmet with the aim of measuring the external noise in order to compensate for it during the data pre-processing. It has to be underlined that environmental noise is not limited to magnetic noise. Mechanical vibrations propagate to the helmet and produce modulation artifacts. Thus, the presence of nearby roads or of slamming doors can considerably degrade the recorded signals. A proper design of the floor, mainly in terms of damping materials, can mitigate this noise source.
Aircraft Noise Exposure and Subjective Sleep Quality: The Results of the DEBATS Study in France
Published in Behavioral Sleep Medicine, 2019
Ali-Mohamed Nassur, Marie Lefèvre, Bernard Laumon, Damien Léger, Anne-Sophie Evrard
Transportation noise is a major source of environmental noise pollution, and it represents a major public health issue. According to the World Health Organization (WHO), transportation noise is estimated to cause at least one million healthy life years lost every year in Western Europe, and sleep disorders are the most serious consequence with more than 900 thousand years of life lost every year, mostly related to road traffic noise (WHO, 2011). In addition, poor sleep, especially short sleep (< 6 hr), has been found to be associated with many major comorbidities, for example, obesity, hypertension, type 2 diabetes, cardiovascular disease, depression, and increased risk of mortality (Cappuccio, D’Elia, Strazzullo, & Miller, 2010; Cappuccio et al., 2008; Gangwisch et al., 2006; Grandner, Jackson, Pak, & Gehrman, 2012; Jones & Rhodes, 2013; Mallon, Broman, & Hetta, 2000; Phillips & Mannino, 2007; Tasali, Leproult, Ehrmann, & Van Cauter, 2008; Vgontzas et al., 2010).