Displaying publications 21 - 40 of 72 in total

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  1. Fulltext Noise-induced hearing loss among quarry workers in a north-eastern state of malaysia: a study on knowledge, attitude and practice
    Ismail AF, Daud A, Ismail Z, Abdullah B
    Oman Med J, 2013 Sep;28(5):331-6.
    PMID: 24044059 DOI: 10.5001/omj.2013.96
    Noise is known to be one of the environmental and occupational hazards listed in the Factory and Machinery Act 1967. Quarries with loud deafening sounds from trucks and machineries pose the risk of noise-induced hearing loss to workers. This study was designed to assess the knowledge, attitude and practice towards noise-induced hearing loss and to determine the prevalence of noise-induced hearing loss and its associated factors among quarry workers in a north-eastern state of Malaysia.
    Matched MeSH terms: Sound
  2. Direct airborne acoustic wave modulation of Fabry-Perot fiber laser (FPFL) over 100 kHz of operating bandwidth
    Pua CH, Ahmad H, Harun SW, De La Rue RM
    Appl Opt, 2012 May 20;51(15):2772-7.
    PMID: 22614578 DOI: 10.1364/AO.51.002772
    The idea of applying a simple Fabry-Perot fiber laser (FPFL) set-up in a free-running condition as an acoustic sensing medium is proposed. Conventional optical microphone requires a stringently aligned diaphragm to mediate the acoustic impedance mismatch between air and silica fiber. Motivated by the difficulty of optical sensing of airborne acoustic waves, a new sensing method is proposed to sense acoustic waves without the assistance of a diaphragm as transducer. By studying the output power fluctuation of the FPFL, the operating bandwidth and sensitivity of the proposed sensing method are determined. The tunability of the resonant frequency from 5 kHz to 85 kHz allows sensing of acoustic waves in the range of 100 Hz to 100 kHz. Tuning of the resonant frequency can be performed by changing the optical pumping power from as low as 10 mW to 68.5 mW or higher.
    Matched MeSH terms: Sound
  3. Lamb to Rayleigh Wave Conversion on Superstrates as a Means to Facilitate Disposable Acoustomicrofluidic Applications
    Wong KS, Lee L, Hung YM, Yeo LY, Tan MK
    Anal Chem, 2019 10 01;91(19):12358-12368.
    PMID: 31500406 DOI: 10.1021/acs.analchem.9b02850
    Rayleigh surface acoustic waves (SAWs) have been demonstrated as a powerful and effective means for driving a wide range of microfluidic actuation processes. Traditionally, SAWs have been generated on piezoelectric substrates, although the cost of the material and the electrode deposition process makes them less amenable as low-cost and disposable components. As such, a "razor-and-blades" model that couples the acoustic energy of the SAW on the piezoelectric substrate through a fluid coupling layer and into a low-cost and, hence, disposable silicon superstrate on which various microfluidic processes can be conducted has been proposed. Nevertheless, it was shown that only bulk vibration in the form of Lamb waves can be excited in the superstrate, which is considerably less efficient and flexible in terms of microfluidic functionality compared to its surface counterpart, that is, the SAW. Here, we reveal an extremely simple way that quite unexpectedly and rather nonintuitively allows SAWs to be generated on the superstrate-by coating the superstrate with a thin gold layer. In addition to verifying the existence of the SAW on the coated superstrate, we carry out finite-difference time domain numerical simulations that not only confirm the experimental observations but also facilitate an understanding of the surprising difference that the coating makes. Finally, we elucidate the various power-dependent particle concentration phenomena that can be carried out in a sessile droplet atop the superstrate and show the possibility for simply carrying out rapid and effective microcentrifugation-a process that is considerably more difficult with Lamb wave excitation on the superstrate.
    Matched MeSH terms: Sound
  4. Fulltext Effect of sea-bottom elasticity on the propagation of acoustic-gravity waves from impacting objects
    Kadri U
    Sci Rep, 2019 Jan 29;9(1):912.
    PMID: 30696934 DOI: 10.1038/s41598-018-37626-z
    Recent analysis of data, recorded on March 8th 2014 at the Comprehensive Nuclear-Test-Ban Treaty Organisation's hydroacoustic stations off Cape Leeuwin Western Australia, and at Diego Garcia, has led to the development of an inverse model for locating impacting objects on the sea surface. The model employs the phase velocity of acoustic-gravity waves that radiate during the impact, and only considers their propagation in the water layer. Here, we address a significant characteristic of acoustic-gravity waves: the ability to penetrate through the sea-bottom, which modifies the propagation speed and thus the arrival time of signals at the hydrophone station. Therefore, we revisit some signals that are associated with the missing Malaysian Aeroplane MH370, and illustrate the role of sea-bottom elasticity on determining impact locations.
    Matched MeSH terms: Sound
  5. Fulltext Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions
    Muhammed D, Anisi MH, Zareei M, Vargas-Rosales C, Khan A
    Sensors (Basel), 2018 Feb 01;18(2).
    PMID: 29389874 DOI: 10.3390/s18020425
    Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal), long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node's cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted.
    Matched MeSH terms: Sound
  6. Fulltext Post-Attentive Integration and Topographic Map Distribution During Audiovisual Processing in Dyslexia: A P300 Event-Related Component Analysis
    Ali SA, Begum T, Reza MF, Fadzil NA, Mustafar F
    Malays J Med Sci, 2020 Jul;27(4):130-138.
    PMID: 32863752 DOI: 10.21315/mjms2020.27.4.12
    Background: Research on audiovisual post-attentive integration has been carried out using a variety of experimental paradigms and experimental groups but not yet studied in dyslexia. We investigated post-attentive integration and topographic voltage distribution in children with dyslexia by analysing the P300 event-related potential (ERP) component.

    Methods: We used a 128-child ERP net for the ERP experiment. Two types of stimuli were presented as either congruent or incongruent stimuli. Congruent stimuli included a matching auditory sound with an animal image, whereas incongruent stimuli included unmatched animal sounds. A total of 24 age-matched children were recruited in the control (n = 12) and dyslexia (n = 12) groups. Children pressed button '1' or '2' when presented with congruent or incongruent stimuli, respectively. The P300 amplitudes and latencies with topographic voltage distribution were analysed for both groups.

    Results: The dyslexia group evoked significantly higher P300 amplitudes at the T4 area than the control group. No significant differences were found in cases of P300 latency. Moreover, the dyslexia group demonstrated a higher intensity of P300 voltage distribution in the right parietal and left occipital areas than the control group.

    Conclusion: Post-attentive integration for children with dyslexia is higher and that this integration process implicated the parietal and occipital areas.

    Matched MeSH terms: Sound
  7. Fulltext Mouth-clicks used by blind expert human echolocators - signal description and model based signal synthesis
    Thaler L, Reich GM, Zhang X, Wang D, Smith GE, Tao Z, et al.
    PLoS Comput Biol, 2017 Aug;13(8):e1005670.
    PMID: 28859082 DOI: 10.1371/journal.pcbi.1005670
    Echolocation is the ability to use sound-echoes to infer spatial information about the environment. Some blind people have developed extraordinary proficiency in echolocation using mouth-clicks. The first step of human biosonar is the transmission (mouth click) and subsequent reception of the resultant sound through the ear. Existing head-related transfer function (HRTF) data bases provide descriptions of reception of the resultant sound. For the current report, we collected a large database of click emissions with three blind people expertly trained in echolocation, which allowed us to perform unprecedented analyses. Specifically, the current report provides the first ever description of the spatial distribution (i.e. beam pattern) of human expert echolocation transmissions, as well as spectro-temporal descriptions at a level of detail not available before. Our data show that transmission levels are fairly constant within a 60° cone emanating from the mouth, but levels drop gradually at further angles, more than for speech. In terms of spectro-temporal features, our data show that emissions are consistently very brief (~3ms duration) with peak frequencies 2-4kHz, but with energy also at 10kHz. This differs from previous reports of durations 3-15ms and peak frequencies 2-8kHz, which were based on less detailed measurements. Based on our measurements we propose to model transmissions as sum of monotones modulated by a decaying exponential, with angular attenuation by a modified cardioid. We provide model parameters for each echolocator. These results are a step towards developing computational models of human biosonar. For example, in bats, spatial and spectro-temporal features of emissions have been used to derive and test model based hypotheses about behaviour. The data we present here suggest similar research opportunities within the context of human echolocation. Relatedly, the data are a basis to develop synthetic models of human echolocation that could be virtual (i.e. simulated) or real (i.e. loudspeaker, microphones), and which will help understanding the link between physical principles and human behaviour.
    Matched MeSH terms: Sound Localization/physiology*; Sound Spectrography
  8. Fulltext Development of a hydrogen gas sensor using a double SAW resonator system at room temperature
    Yunusa Z, Hamidon MN, Ismail A, Mohd Isa M, Yaacob MH, Rahmanian S, et al.
    Sensors (Basel), 2015;15(3):4749-65.
    PMID: 25730480 DOI: 10.3390/s150304749
    A double SAW resonator system was developed as a novel method for gas sensing applications. The proposed system was investigated for hydrogen sensing. Commercial Surface Acoustic Wave (SAW) resonators with resonance frequencies of 433.92 MHz and 433.42 MHz were employed in the double SAW resonator system configuration. The advantages of using this configuration include its ability for remote measurements, and insensitivity to vibrations and other external disturbances. The sensitive layer is composed of functionalized multiwalled carbon nanotubes and polyaniline nanofibers which were deposited on pre-patterned platinum metal electrodes fabricated on a piezoelectric substrate. This was mounted into the DSAWR circuit and connected in parallel. The sensor response was measured as the difference between the resonance frequencies of the SAW resonators, which is a measure of the gas concentration. The sensor showed good response towards hydrogen with a minimum detection limit of 1%.
    Matched MeSH terms: Sound
  9. Fulltext Chronology of Fabry-Perot interferometer fiber-optic sensors and their applications: a review
    Islam MR, Ali MM, Lai MH, Lim KS, Ahmad H
    Sensors (Basel), 2014;14(4):7451-88.
    PMID: 24763250 DOI: 10.3390/s140407451
    Optical fibers have been involved in the area of sensing applications for more than four decades. Moreover, interferometric optical fiber sensors have attracted broad interest for their prospective applications in sensing temperature, refractive index, strain measurement, pressure, acoustic wave, vibration, magnetic field, and voltage. During this time, numerous types of interferometers have been developed such as Fabry-Perot, Michelson, Mach-Zehnder, Sagnac Fiber, and Common-path interferometers. Fabry-Perot interferometer (FPI) fiber-optic sensors have been extensively investigated for their exceedingly effective, simple fabrication as well as low cost aspects. In this study, a wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications. The chronology of the development of FPI sensors and their implementation in various applications are discussed.
    Matched MeSH terms: Sound
  10. Fulltext Vocalisation Repertoire of Female Bluefin Gurnard (Chelidonichthys kumu) in Captivity: Sound Structure, Context and Vocal Activity
    Radford CA, Ghazali SM, Montgomery JC, Jeffs AG
    PLoS One, 2016;11(2):e0149338.
    PMID: 26890124 DOI: 10.1371/journal.pone.0149338
    Fish vocalisation is often a major component of underwater soundscapes. Therefore, interpretation of these soundscapes requires an understanding of the vocalisation characteristics of common soniferous fish species. This study of captive female bluefin gurnard, Chelidonichthys kumu, aims to formally characterise their vocalisation sounds and daily pattern of sound production. Four types of sound were produced and characterised, twice as many as previously reported in this species. These sounds fit two aural categories; grunt and growl, the mean peak frequencies for which ranged between 129 to 215 Hz. This species vocalized throughout the 24 hour period at an average rate of (18.5 ± 2.0 sounds fish-1 h-1) with an increase in vocalization rate at dawn and dusk. Competitive feeding did not elevate vocalisation as has been found in other gurnard species. Bluefin gurnard are common in coastal waters of New Zealand, Australia and Japan and, given their vocalization rate, are likely to be significant contributors to ambient underwater soundscape in these areas.
    Matched MeSH terms: Sound
  11. Fulltext A Theoretical Study of Surface Mode Propagation with a Guiding Layer of GaN/Sapphire Hetero-Structure in Liquid Medium
    Mohd Razip Wee MF, Jaafar MM, Faiz MS, Dee CF, Yeop Majlis B
    Biosensors (Basel), 2018 Dec 05;8(4).
    PMID: 30563159 DOI: 10.3390/bios8040124
    Gallium Nitride (GaN) is considered as the second most popular semiconductor material in industry after silicon. This is due to its wide applications encompassing Light Emitting Diode (LED) and power electronics. In addition, its piezoelectric properties are fascinating to be explored as electromechanical material for the development of diverse microelectromechanical systems (MEMS) application. In this article, we conducted a theoretical study concerning surface mode propagation, especially Rayleigh and Sezawa mode in the layered GaN/sapphire structure with the presence of various guiding layers. It is demonstrated that the increase in thickness of guiding layer will decrease the phase velocities of surface mode depending on the material properties of the layer. In addition, the Q-factor value indicating the resonance properties of surface mode appeared to be affected with the presence of fluid domain, particularly in the Rayleigh mode. Meanwhile, the peak for Sezawa mode shows the highest Q factor and is not altered by the presence of fluid. Based on these theoretical results using the finite element method, it could contribute to the development of a GaN-based device to generate surface acoustic wave, especially in Sezawa mode which could be useful in acoustophoresis, lab on-chip and microfluidics applications.
    Matched MeSH terms: Sound
  12. Fulltext Enhancing rate of water absorption in seeds via a miniature surface acoustic wave device
    Wong KS, Lee L, Yeo LY, Tan MK
    R Soc Open Sci, 2019 Mar;6(3):181560.
    PMID: 31032012 DOI: 10.1098/rsos.181560
    Seeds, which are high in protein and essential nutrients, must go through a hydration process before consumption. The ability to rapidly increase water absorption can significantly reduce the soaking time as well as the amount of energy needed for cooking seeds. Many studies in the literature employ high-power (102 W) low-frequency (104 Hz) ultrasound; although their results are very promising where more than 100% increase in water content can be obtained between the treated and untreated seeds, the high-power and low-frequency ultrasound often causes acoustic cavitation under high intensity, which can severely disrupt the cell walls and damage the seeds. In our study, however, we demonstrate that treating the seeds via a miniature surface acoustic wave device, which operates at low-power (100 W) and high-frequency (107 Hz) range, gives rise to a higher water absorption rate without the acoustic cavitations. By comparing the water content between the treated and untreated seeds, an increase of up to 2600% (for chickpeas) and 6350% (for mung bean) can be obtained after 60 min. A significantly higher water absorption in mung beans can be attributed to the larger pore size when compared with the acoustic wavelength in water, enabling an efficient transmission of acoustic wave inside the pores. Our results also indicate that the germination time can be reduced by half for treated seeds as compared to the untreated seeds.
    Matched MeSH terms: Sound
  13. Fulltext Compact Elliptical UWB Antenna for Underwater Wireless Communications
    Alhawari ARH, Majeed SF, Saeidi T, Mumtaz S, Alghamdi H, Hindi AT, et al.
    Micromachines (Basel), 2021 Apr 07;12(4).
    PMID: 33917167 DOI: 10.3390/mi12040411
    The increasing needs of free licensed frequency bands like Industrial, Scientific, and Medical (ISM), Wireless Local Area Network (WLAN), and 5G for underwater communications required more bandwidth (BW) with higher data transferring rate. Microwaves produce a higher transferring rate of data, and their associated devices are smaller in comparison with sonar and ultrasonic. Thus, transceivers should have broad BW to cover more of a frequency band, especially from ultra-wideband (UWB) systems, which show potential outcomes. However, previous designs of similar work for underwater communications were very complicated, uneasy to fabricate, and large. Therefore, to overcome these shortcomings, a novel compact elliptical UWB antenna is designed to resonate from 1.3 to 7.2 GHz. It is invented from a polytetrafluoroethylene (PTFE) layer with a dielectric constant of 2.55 mm and a thickness of 0.8 mm. The proposed antenna shows higher gain and radiation efficiency and stability throughout the working band when compared to recent similarly reported designs, even at a smaller size. The characteristics of the functioning antenna are investigated through fluid mediums of fresh-water, seawater, distilled water, and Debye model water. Later, its channel capacity, bit rate error, and data rate are evaluated. The results demonstrated that the antenna offers compact, easier fabrication with better UWB characteristics for underwater 5G communications.
    Matched MeSH terms: Sound
  14. Fulltext THE PERFORMANCE ANALYSIS OF OPTICAL WAVE PROPAGATION FOR UNDERWATER WIRELESS COMMUNICATION
    MUHAMMAD SAFIY SABRIL, MUHAMMAD SAFIY SABRIL, FAEZAH JASMAN, NURUL ADILAH ABDUL LATIFF, SEVIA MAHDALIZA IDRUS, WAN HAFIZA WAN HASSAN
    UMT Journal of Undergraduate Research, 2020;2(3):73-82.
    MyJurnal
    Underwater wireless communications refer to transmitting data in an unguided water environment by wireless carriers including acoustic, radio frequency (RF), and optical waves. Relative to acoustic and RF, the optical wave is more promising to offer higher bandwidth at a lower energy consumption rate. However, an optical wave has its challenges such as attenuation due to absorption, scattering and turbulence effects. Therefore, this work attempts to investigate the performance of lightwave propagation for underwater optical wireless communication (UOWC) using simulation and experimental approaches. First, the performance of optical waves was analyzed using MATLAB by simulating the light attenuation model which based on depth-dependent chlorophyll concentration. A depth profile that related to the surface chlorophyll levels for the range 0-4 mg/m3 was used to represent the open ocean. The simulation showed that the attenuation of light less affected for operating wavelength range of 450 – 550 nm. Further, an experimental set-up was developed which consists of a transmitter, receiver, and aquarium to emulate the UOWC channel. Three types of water including clear, sea and cloudy were tested to analyze their interaction with the light emitted by a light-emitting diode (LED) and a laser diode. The emitted light detected by the light sensor and the strength of an audio signal transmitted through the UOWC were measured using a light meter and sound meter respectively. The measured power was plotted against distance and the attenuation constant c was deduced through curve fitting method. The analysis showed irrespective of the light sources, UOWC in cloudy water suffered the highest attenuation relative to still clear and seawater. The received power emitted by laser was at least 41% higher than the LED. This study contributes to identify the potential and limitations of different operating schemes to optimize UOWC performance.
    Matched MeSH terms: Sound
  15. The prioritization of visuo-spatial associations during mental imagery
    Umar H, Mast FW, Cacchione T, Martarelli CS
    Cogn Process, 2021 May;22(2):227-237.
    PMID: 33404898 DOI: 10.1007/s10339-020-01010-5
    While previous research has shown that during mental imagery participants look back to areas visited during encoding it is unclear what happens when information presented during encoding is incongruent. To investigate this research question, we presented 30 participants with incongruent audio-visual associations (e.g. the image of a car paired with the sound of a cat) and later asked them to create a congruent mental representation based on the auditory cue (e.g. to create a mental representation of a cat while hearing the sound of a cat). The results revealed that participants spent more time in the areas where they previously saw the object and that incongruent audio-visual information during encoding did not appear to interfere with the generation and maintenance of mental images. This finding suggests that eye movements can be flexibly employed during mental imagery depending on the demands of the task.
    Matched MeSH terms: Sound
  16. The effects of audio stimuli on auditory-evoked potential in normal hearing Malay adults
    Ibrahim IA, Ting HN, Moghavvemi M
    Int J Health Sci (Qassim), 2018 9 12;12(5):25-34.
    PMID: 30202405
    Objectives: The hearing process in the brain is very complicated and hard to solve. However, an understanding of the hearing process is an essential issue and needed in many rehabilitation or treatment applications. This study investigates and compares the effects of simple and complex sounds on latency and amplitude of various event-related potential (ERP) components to male ethnic Malay adults. Comparisons were made with previous studies.

    Materials and Methods: Simple and complex sounds were used (pure tones and the naturally produced Malay consonant-vowels [CVs]) to evoke the cortical auditory-evoked potential (CAEP) signals. Moreover, this study analyzed the influence of related CAEP components that are distinct to the selected population and determined which of the ERP components among (CAEP) components is most affected by the two distinct stimuli. Moreover, the study used classification algorithms to discover the ability of the brain in distinguishing CAEP evoked by stimuli contrasts.

    Results: The results showed some resemblance between our results and ERP waveforms outlined in previous studies conducted on native speakers of English. On the other hand, it was also observed that the P1 and N2 had a significant effect in amplitude due to different stimulus.

    Conclusion: The results show high classification accuracy for the brain to distinguish auditory stimuli. Moreover, the results indicated some resemblance to previous studies conducted on native English speakers using similar tones and English CV stimuli. However, the amplitudes and latencies of the P1 were found to have a significant difference due to stimuli complexity.

    Matched MeSH terms: Sound
  17. Graphene-mediated microfluidic transport and nebulization via high frequency Rayleigh wave substrate excitation
    Ang KM, Yeo LY, Hung YM, Tan MK
    Lab Chip, 2016 09 21;16(18):3503-14.
    PMID: 27502324 DOI: 10.1039/c6lc00780e
    The deposition of a thin graphene film atop a chip scale piezoelectric substrate on which surface acoustic waves are excited is observed to enhance its performance for fluid transport and manipulation considerably, which can be exploited to achieve further efficiency gains in these devices. Such gains can then enable complete integration and miniaturization for true portability for a variety of microfluidic applications across drug delivery, biosensing and point-of-care diagnostics, among others, where field-use, point-of-collection or point-of-care functionality is desired. In addition to a first demonstration of vibration-induced molecular transport in graphene films, we show that the coupling of the surface acoustic wave gives rise to antisymmetric Lamb waves in the film which enhance molecular diffusion and hence the flow through the interstitial layers that make up the film. Above a critical input power, the strong substrate vibration displacement can also force the molecules out of the graphene film to form a thin fluid layer, which subsequently destabilizes and breaks up to form a mist of micron dimension aerosol droplets. We provide physical insight into this coupling through a simple numerical model, verified through experiments, and show several-fold improvement in the rate of fluid transport through the film, and up to 55% enhancement in the rate of fluid atomization from the film using this simple method.
    Matched MeSH terms: Sound
  18. Prevalence and associated factors of hearing impairment in aviation and manufacturing industry in Selangor
    Ahmad Syazrin Muhamad
    Journal of Occupational Safety and Health, 2011;8(2):35-44.
    MyJurnal
    Sound is one of the source of energy generated by vibration and is carried through the air in a form of pressure waves (Frederick, 1975). This pressure waves consist of pulsation or vibration of molecules of an elastic medium such as gas, liquid and even solid (Gerber, 1974). Due to its nature, sound can be irritating when it is excessive. The excessive amount of sound is called noise. Exposure to noise is common to the workers working at the industry. This can lead to hearing loss. Hearing loss is one of the most common health problems in the industrialized world. Working activities have been related to noise exposure due to increase use of machine that generates sounds. Many workers throughout the world experience hazardous noise exposure which is ≥ 85 decibels (dB) (Seter, 1998). Based on the previous study in the European region, most of the employers had difficulties to compensate workers diagnosed with hearing loss or hearing impairment cause by the working nature. (Rachiotis et al., 2006). According to European Survey on Working Conditions, about 7% of the workers considered that their work affects their health in the form of hearing disorders. Occupational risk factors for hearing loss include occupational noise, whole body vibration, work-related diseases and exposure to chemical. In this report, we specified in the noise exposure level of the workers.
    Matched MeSH terms: Sound
  19. An in-depth review of the methods, findings, and theories associated with odor-evoked autobiographical memory
    Hackländer RPM, Janssen SMJ, Bermeitinger C
    Psychon Bull Rev, 2019 Apr;26(2):401-429.
    PMID: 30406397 DOI: 10.3758/s13423-018-1545-3
    Over the past nearly 35 years, there has been sporadic interest in what has commonly come to be known as the Proust phenomenon, whereby autobiographical memories are retrieved and experienced differently when evoked by odors as compared with other types of cues, such as words, images or sounds. The purpose of this review is threefold. First, we provide a detailed analysis of the methods used to investigate Proust effects. Second, we review and analyze the various findings from the literature and determine what we feel to be the most important and stable findings. Third, we provide a series of previously postulated and new hypotheses that attempt to account for the various findings. Given the early stage of research, the current review aims to provide a measure of organization to the field, as well serve as a guide for how future investigations may address the topic. We conclude with the recommendation that research in this area shift its focus from establishing the phenomenon towards explaining its causes.
    Matched MeSH terms: Sound
  20. Fulltext Rewinding the waves: tracking underwater signals to their source
    Kadri U, Crivelli D, Parsons W, Colbourne B, Ryan A
    Sci Rep, 2017 10 24;7(1):13949.
    PMID: 29066744 DOI: 10.1038/s41598-017-14177-3
    Analysis of data, recorded on March 8th 2014 at the Comprehensive Nuclear-Test-Ban Treaty Organisation's hydroacoustic stations off Cape Leeuwin Western Australia, and at Diego Garcia, reveal unique pressure signatures that could be associated with objects impacting at the sea surface, such as falling meteorites, or the missing Malaysian Aeroplane MH370. To examine the recorded signatures, we carried out experiments with spheres impacting at the surface of a water tank, where we observed almost identical pressure signature structures. While the pressure structure is unique to impacting objects, the evolution of the radiated acoustic waves carries information on the source. Employing acoustic-gravity wave theory we present an analytical inverse method to retrieve the impact time and location. The solution was validated using field observations of recent earthquakes, where we were able to calculate the eruption time and location to a satisfactory degree of accuracy. Moreover, numerical validations confirm an error below 0.02% for events at relatively large distances of over 1000 km. The method can be developed to calculate other essential properties such as impact duration and geometry. Besides impacting objects and earthquakes, the method could help in identifying the location of underwater explosions and landslides.
    Matched MeSH terms: Sound
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