Search

Introduction: Colored noises with acoustic and psychoacoustic characteristics have several biological effects on human or animal health. While studies on auditory effects focus on noise’s physical aspects, its psychoacoustic aspects can also result in health and safety risks. Therefore, this study aims to investigate frequency-based damages due to exposure to colored noise in an animal model. Material and Methods: Twenty-four male Wistar rats were randomly divided into four groups (6 in each group). The groups included the control (no exposure) and three exposure groups (white, pink, and violet). The rats were exposed to 110 dB SPL for 4 hr/day for 14 consecutive days. Auditory brainstem responses (ABR) with click and tone-burst stimuli were recorded one day before (baseline), 7, and 14 days after exposure. Statistical analyses were conducted using ANOVA and repeated measures ANOVA. Results: There was a statistically significant increase in ABR threshold values in exposure groups (p

Background: Most patients with traumatic brain injury (TBI) admitted to the intensive care unit experience pain. Nurses have a major role in pain management in patients with TBI.Aim: This study was performed aimed to investigate the effect of white noise on pain in unconscious patients with TBI.Method: This single-blind clinical trial study was performed in 2019 on 52 unconscious patients with TBI admitted in neurological intensive care unit in Ardabil. They were randomly assigned to the control and intervention groups. In the intervention group, patients received 30 minutes white noise for 3 consecutive days. In the control group, patients rested only on the bed at the same time. The demographic characteristics form and behavioral pain scale were used to collect data. P

This study presents a new estimate for subsidence in the northeast of the country through the time series analysis of 11-year (from the beginning of 2006 till the end of 2016) of 31 stations of the Khorasan network, as part of the Iranian Permanent Geodynamic & GNSS Network (IPGN), located in northeastern Iran. The mentioned estimation is obtained from the velocity vector of network stations in the International Terrestrial Reference Frame of ITRF2014 based on time series analysis in two realms, i.e., deterministic model analysis and stochastic model analysis. The deterministic model analysis is comprised of jump detection, determination of station motion model parameters, the study of station trend, outlier detection, and statistical significance test to check the jumps magnitude. Due to the interdependence of these steps, the related calculations are performed iteratively. Noise analysis includes two phases, namely, spatial filtering and temporal filtering. In the first phase, the Common Mode Error (CME) parameter is calculated using the weighted stacking method and taking into account the data correlation coefficient and stations distance. In the second phase, using the maximum likelihood estimation (MLE) method, the optimal noise model is derived as a combination of white noise and flicker noise. As a result, the reliable velocities of the stations (resulting from a complete analysis of the deterministic model) and their realistic uncertainties (resulting from the selection of optimal stochastic models) are calculated. Based on this study we found that: (1) Each station during the 11-year study period has on average nine jumps, all of which are of non-seismic origin. (2) Including the data from all IPGN stations in spatial filtering, leads to better results and on average reduces the norm of post-fit residual vectors for east, north, and up coordinate components by 30.17%, 29.40%, and 17.90%, respectively. (3) Concerning the temporal filtering, we found that the noise of the up-component is significantly higher than the noise of the horizontal components. (4) Stochastic model analysis showed the realistic uncertainties of the east, north, and up components are 4.33, 4.44, and 3.70 times, respectively, greater than the uncertainties which are derived without application of stochastic modeling (optimistic uncertainties). (5) The vertical velocity of most of stations was found to be in the normal range of -5 to 5 mm/yr. (6) Five stations, namely, GOLM, GRGN, NFRD, NISH, and SHRN are having anomalous subsidence (up to 9 mm/yr). (7) The proximity of the three stations GOLM, NFRD, and NISH allows us to infer a regional subsidence for the area of their location. (8) The station GRGN, in addition to anomalous subsidence, shows distinctive features such as the nonlinear trend as well as large periodic signals in the up component of the station. Therefore, to find the reason for such vertical behavior of the earth's crust more permanent GNSS stations must be established in that area. (9) The estimated parameters of periodic signal of the stations demonstrate that the annual and draconitic year signals have the largest amplitudes in the three coordinate components. In addition, amplitude of the periodic signals of the up component is significantly larger than the other components. [ABSTRACT FROM AUTHOR]

Introduction: The study of noise has always been of interest to occupational health professionals as a harmful physical factor in the workplace. However, the psychological and psychoacoustic aspects of noise in the workplace have been less studied. This study has dealt with different colors of noise and their applications in psychoacoustics. Material and Methods: This review study was conducted by searching the databases of Google Scholar, ProQuest, Science Direct, PubMed, and Scopus to extract the articles related to the research subject within a 50-year interval from 1970 to 2020. Results: Based on the results of the present study, colored noises and white noise seem to have the potential to be used as acoustic stimuli to improve the sleep of employees, especially shift workers, to improve memory and attention, especially in jobs that require high care and attention. Colored noise and white noise have potential applications to improve cognitive function in different occupations to reduce the activity of the sympathetic nervous system and anxiety and stress, especially in jobs with high job stress. Also, these noises are helpful for people’s privacy, especially in the open workplace, for noise masking and noise control purposes, as well as for medicine and treatment of disorders such as tinnitus, ADHD, and hyperacusis. Conclusion: Paying attention to the colors of noise and their psychoacoustic impacts shows us that the noise impacts are not limited to their undesirable and damaging effects. Instead, their positive and applied aspects should also note. Familiarity with such aspects and their introduction can identify the existing information gaps in this field and pave the way to fill them.

Background: Patients undergoing coronary artery bypass graft (CABG) surgery face a serious psychological problem called death anxiety, which can harm the patient physically, socially, and emotionally. White noise and Benson’s relaxation technique are among the complementary and effective treatments which help mitigate death anxiety in these patients.Aim: This study aimed to investigate the impact of white noise and Benson’s relaxation technique on death anxiety among patients undergoing CABG.Method: This randomized clinical trial study was performed on 60 hospitalized patients in Iran in 2020. The permutated block method was used to randomly divide the eligible participants into intervention and control groups. In the intervention group, participants accomplished Benson’s technique with white noise music on three consecutive occasions in the morning, afternoon, and before night sleep. The control group did not receive any intervention. The demographic and clinical characteristics form and Templer scale were used to collect data. Data were analyzed using SPSS software (Version 25).Results: The mean±SD age of the participants was 61.97±8.80 and 64.81±6.53 years in the intervention and control groups, respectively. The results showed a significant decrease in the mean score of death anxiety in the intervention group (P

Introduction: One of the most important complications of exposure to noises is changes in the gene expression patterns. Irreversible damage to the inner ear, such as noise-induced hearing loss (NIHL), is caused by tissue damage and changes in the gene expressions in the auditory system. Changes in the GJB2 gene expression pattern lead to autosomal deafness at different loci. The present study aims to evaluate the GJB2 gene expression in cochlear tissue exposed to white noise. Material and Methods: In this study, ten male Westar rats were divided into two experimental (W1, W2) groups of six rats and a control (normal) group of four rats. Two experimental groups were exposed to constant white noise in the frequency range of 100-20000 Hz and the sound pressure level of 118-120 dB. In order to study the histology and gene expression, after a cochlea biopsy, the histological tests, RNA extraction, cDNA synthesis, and qRT-PCR analysis were performed. Results: The results showed that the transcript level of GJB2 was significantly decreased in both experimental groups W1 and W2 by 0.02 and 0.12-fold, respectively (p

physical systems are mostly modeled by certain differential equations. However, in most cases random effects are omitted and therefore, the solutions are not in agreement with the experimental results. In the present work, we have investigated the effect of white noise perturbation on two physical models. At first, we have reviewed the random variables and processes and then, we have solved the Langevin equation, which is a general form of a random equation with a random white noise perturbation. We have also proposed a stochastic model for both the electric current and radiation of radioactive materials. This is done by considering the white noise perturbation sentence in the corresponding ordinary differential equations. By solving these random equations, we have obtained the mean value function, the variance function, and the random process function, as well. Finally, the results have been simulated and the corresponding diagrams presented. In order to simulate the desired random movement, the Monte Carlo method in Microsoft Excel environment was used.

Background: Learning new words, visual memory, and selective attention are among the factors that influence the academic achievement of elementary students. But the key question is: does white noise affect students' learning new words, visual memory, and selective attention? Aims: To investigate the effect of white noise on learning new words, active visual cue and selective attention in elementary school students. Method: The study was experimental with pre-test and post-test with control group. The statistical population was all the elementary students of second year of Bavi city of Khuzestan province in the academic year of 1397-98. Group 50 (n = 50) were randomly assigned. Research tools include the New Words Researcher Test, Jean-Louis Celie's Visual Active Memory Test (2012), and Selective Attention Testing, Concentration and Attempt d2 (Bagheri, 2012). Data were analyzed using multivariate covariance method. Results: White noise had a significant effect on learning new words in elementary students (P0/05) and selective attention (P>0/470). Conclusions: White noise can be used to enhance the learning of new words in elementary school students.

In this paper, a novel dynamic model is proposed for an actively damped boring bar equipped with electromagnetic actuator. The dynamic models of actuator and boring bar are obtained by using the suggested systematic identification approach, which is based upon the fundamental tools and techniques of system identification theory. The electro-mechanical system or the forward path is consisted of 3 basic components, i.e. linear power amplifier, electrodynamic shaker, and boring bar structure. In this paper, the dynamic models of forward path’s subsystems are simultaneously identified. The component-based identification approach has led to a remarkable finding about the source of nonlinearity in the dynamic model of forward path. According to the presented experimental observations, it has been concluded that electromagnetic actuator can be modeled as a linear dynamic system, while the boring bar structure exhibits nonlinear behavior, since the prediction accuracy of boring bar dynamic model is drastically reduced by changing the amplitude of excitation. As a result, a new parameter varying dynamic model is presented for describing the dynamic behavior of forward path in terms of both frequency and excitation level. The proposed dynamic model has a predefined representation with the least possible mathematical order. It can anticipate the time domain response of forward path due to chirp excitation with 88% accuracy. In addition, during the validation stage, the proposed model forecasts the dynamic response of system due to Gaussian white noise excitation with remarkable accuracy. Moreover, the dynamic model of electromagnetic actuator can predict the dynamic force signature of actuator with 85% accuracy. [ABSTRACT FROM AUTHOR]

Empirical mode decomposition (EMD) is one of the new methods for decomposing a signal into its constituent components. The existence of multiple error sources has led to activities to eliminate or mitigate their effects. In this research, one of the major problems of EMD for the separation of noise-polluted signals, namely, mode mixing problem has been studied. To solve this problem, bandwidth EMD has been used, which enhances the EMD method and processes speed and greatly prevents mode mixing problem. Also, among the available methods to extract the instantaneous properties, the proper pair of instantaneous properties identification and signal normalization method is presented by an example. To investigate the efficiency of the bandwidth EMD method, using the optimal method of extracting the instantaneous properties, the experimental data of a faulty bearing have been studied and the instantaneous properties of both EMD method and the bandwidth EMD method have been extracted. Using the coefficient of variation criterion, it is shown that the bandwidth EMD method has a higher resolution and better results than EMD method. Finally, using information of decomposed white noise by EMD, the noise isolation quality of the original data is examined, which indicates a better decomposition of the results of the bandwidth EMD method. [ABSTRACT FROM AUTHOR]