Observation of Ultra-High-Q Resonators in the Ultrasound via Bound States in the Continuum.

The confinement of waves in open systems represents a fundamental phenomenon extensively explored across various branches of wave physics. Recently, significant attention is directed toward bound states in the continuum (BIC), a class of modes that are trapped but do not decay in an otherwise unbounded continuum. Here, the theoretical investigation and experimental demonstration of the existence of quasi-bound states in the continuum (QBIC) for ultrasonic waves are achieved by leveraging an elastic Fabry-Pérot metasurface resonator. Several intriguing properties of the ultrasound quasi-bound states in the continuum that are robust to parameter scanning are unveiled, and experimental evidence of a remarkable Q-factor of 350 at ≈1 MHz frequency, far exceeding the state-of-the-art using a fully acoustic underwater system is presented. The findings contribute novel insights into the understanding of BIC for acoustic waves, offering a new paradigm for the design of efficient, ultra-high Q-factor ultrasound devices.

Deep Learning for Neuromuscular Control of Vocal Source for Voice Production.

A computational neuromuscular control system that generates lung pressure and three intrinsic laryngeal muscle activations (cricothyroid, thyroarytenoid, and lateral cricoarytenoid) to control the vocal source was developed. In the current study, LeTalker, a biophysical computational model of the vocal system was used as the physical plant. In the LeTalker, a three-mass vocal fold model was used to simulate self-sustained vocal fold oscillation. A constant/ǝ/vowel was used for the vocal tract shape. The trachea was modeled after MRI measurements. The neuromuscular control system generates control parameters to achieve four acoustic targets (fundamental frequency, sound pressure level, normalized spectral centroid, and signal-to-noise ratio) and four somatosensory targets (vocal fold length, and longitudinal fiber stress in the three vocal fold layers). The deep-learning-based control system comprises one acoustic feedforward controller and two feedback (acoustic and somatosensory) controllers. Fifty thousand steady speech signals were generated using the LeTalker for training the control system. The results demonstrated that the control system was able to generate the lung pressure and the three muscle activations such that the four acoustic and four somatosensory targets were reached with high accuracy. After training, the motor command corrections from the feedback controllers were minimal compared to the feedforward controller except for thyroarytenoid muscle activation.

Morphology and vocalization comparison of the Houston Toad and the Dwarf American Toad: implications for their historic range.

Documenting changes in the distribution and abundance of a given taxon requires historical data. In the absence of long-term monitoring data collected throughout the range of a taxon, conservation biologists often rely on preserved museum specimens to determine the past or present, putative geographic distribution. Distributional data for the Houston Toad (Anaxyrus houstonensis) has consistently been confounded by similarities with a sympatric congener, the Dwarf American Toad (A. americanus charlesmithi), both in monitoring data derived from chorusing surveys, and in historical data via museum specimens. In this case, misidentification can have unintended impacts on conservation efforts, where the Houston Toad is federally endangered, and the Dwarf American Toad is of least concern. Previously published reports have compared these two taxon on the basis of their male advertisement call and morphological appearance, often with the goal of using these characters to substantiate their taxonomic status prior to the advent of DNA sequencing technology. However, numerous studies report findings that contradict one another, and no consensus on the true differences or similarities can be drawn. Here, we use contemporary recordings of wild populations of each taxon to test for quantifiable differences in male advertisement call. Additionally, we quantitatively examine a subset of vouchered museum specimens representing each taxon to test previously reported differentiating morphometric characters used to distinguish among other Bufonids of East-Central Texas, USA. Finally, we assemble and qualitatively evaluate a database of photographs representing catalogued museum vouchers for each taxon to determine if their previously documented historic ranges may be larger than are currently accepted. Our findings reveal quantifiable differences between two allopatric congeners with respect to their male advertisement call, whereas we found similarities among their detailed morphology. Additionally, we report on the existence of additional, historically overlooked, museum records for the Houston Toad in the context of its putative historic range, and discuss errors associated with the curation of these specimens whose identity and nomenclature have not been consistent through time. These results bookend decades of disagreement regarding the morphology, voice, and historic distribution of these taxa, and alert practitioners of conservation efforts for the Houston Toad to previously unreported locations of occurrence.

Assessing the multidimensional comfort of earplugs in virtual industrial noise environments.

Earplugs' comfort is primarily evaluated through cost-effective laboratory evaluations, yet these evaluations often inadequately capture the multidimensional comfort aspects due to design limitations that do not replicate real-world conditions. This paper introduces a novel laboratory method for comprehensive assessment of the multidimensional comfort aspects of earplugs, combining questionnaire-based evaluations and objective perceptual tests within virtual industrial sound environments replicating in-situ noise exposure. Objective perceptual results confirm that the sound environment affect participants' ability to detect alarms in a noisy environment and comprehend speech-in-noise while wearing earplugs. Subjective questionnaire results reveal that the earplugs family has an effect on the primary attributes of the acoustical, physical and functional comfort's dimension. Participants reported the physical dimension as the most important factor they take into account when evaluating earplugs' comfort. The functional dimension was considered the second most important factor by the participants, followed by the psychological dimension, and the acoustical dimension.

Resolution limits for radiation-induced acoustic imaging for in vivo radiation dosimetry.

OBJECTIVE: Radiation-induced acoustic (RA) computed tomographic (RACT) imaging is being thoroughly explored for radiation dosimetry. It is essential to understand how key machine parameters like beam pulse, size, and energy deposition affect image quality in RACT. We investigate the intricate interplay of these parameters and how these factors influence dose map resolution in RACT. APPROACH: We first conduct an analytical assessment of time-domain RA signals and their corresponding frequency spectra for certain testcases, and computationally validate these analyses. Subsequently, we simulated a series of X-ray-based RACT (XACT) experiments and compared the simulations with experimental measurements. In-silico reconstruction studies have also been conducted to demonstrate the resolution limits imposed by the temporal pulse profiles on RACT. XACT experiments were performed using clinical machines and the reconstructions were analyzed for resolution capabilities. MAIN RESULTS: Our paper establishes the theory for predicting the time- and frequency-domain behavior of RA signals. We illustrate that the frequency content of RA signal is not solely dependent on the spatial energy deposition characteristics but also on the temporal features of radiation. The same spatial energy deposition through a Gaussian pulse and a rectangular pulse of equal pulsewidths results in different frequency spectra of the RA signals. RA signals corresponding to the rectangular pulse exhibit more high-frequency content than their Gaussian pulse counterparts and hence provide better resolution in the reconstructions. XACT experiments with ~3.2 us and ~4 us rectangular radiation pulses were performed, and the reconstruction results were found to correlate well with the in-silico results. SIGNIFICANCE: Here, we discuss the inherent resolution limits for RACT-based radiation dosimetric systems. While our study is relevant to the broader community engaged in research on photoacoustics, X-ray-acoustics, and proto/ionoacoustics, it holds particular significance for medical physics researchers aiming to set up RACT for dosimetry and radiography using clinical radiation machines.

Natural soundscapes of lowland river habitats and the potential threat of urban noise pollution to migratory fish.

Migratory fish populations have experienced great declines, and considerable effort have been put into reducing stressors, such as chemical pollution and physical barriers. However, the importance of natural sounds as an information source and potential problems caused by noise pollution remain largely unexplored. The spatial distribution of sound sources and variation in propagation characteristics could provide migratory fish with acoustic cues about habitat suitability, predator presence, food availability and conspecific presence. We here investigated the relationship between natural soundscapes and local river conditions and we explored the presence of human-related sounds in these natural soundscapes. We found that 1a) natural river sound profiles vary with river scale and cross-sectional position, and that 1b) depth, width, water velocity, and distance from shore were all significant factors in explaining local soundscape variation. We also found 2a) audible human activities in almost all our underwater recordings and urban and suburban river parts had elevated sound levels relative to rural river parts. Furthermore, 2b) daytime levels were louder than night time sound levels, and bridges and nearby road traffic were much more prominent with diurnal and weekly patterns of anthropogenic noise in the river systems. We believe our data show high potential for natural soundscapes of low-land river habitat to serve as important environmental cues to migratory fish. However, anthropogenic noise may be particularly problematic due to the omnipresence, and relatively loud levels relative to the modest dynamic range of the natural sound sources, in these slow-flowing freshwater systems.

Feature Extraction Methods for Underwater Acoustic Target Recognition of Divers.

The extraction of typical features of underwater target signals and excellent recognition algorithms are the keys to achieving underwater acoustic target recognition of divers. This paper proposes a feature extraction method for diver signals: frequency-domain multi-sub-band energy (FMSE), aiming to achieve accurate recognition of diver underwater acoustic targets by passive sonar. The impact of the presence or absence of targets, different numbers of targets, different signal-to-noise ratios, and different detection distances on this method was studied based on experimental data under different conditions, such as water pools and lakes. It was found that the FMSE method has the best robustness and performance compared with two other signal feature extraction methods: mel frequency cepstral coefficient filtering and gammatone frequency cepstral coefficient filtering. Combined with the commonly used recognition algorithm of support vector machines, the FMSE method can achieve a comprehensive recognition accuracy of over 94% for frogman underwater acoustic targets. This indicates that the FMSE method is suitable for underwater acoustic recognition of diver targets.

The Effect of Rapeseed Oil Biopolyols and Cellulose Biofillers on Selected Properties of Viscoelastic Polyurethane Foams.

This paper presents the results of research on polyurethane viscoelastic foams (PUVFs) modified with biomaterials. This investigation looked at the effect of the biomaterials on the foaming processes, as well as the acoustical and selected physical-mechanical properties of the foams. Various types of rapeseed oil biopolyols and microcellulose were used to modify the materials. The analysis of properties covered a reference biopolyol-free sample and materials containing 10 wt.%, 20 wt.%, and 30 wt.% of different types of biopolyols in the mixture of polyol components. The biopolyols differed in terms of functionality and hydroxyl value (OHv). Next, a selected formulation was modified with various microcellulose biofillers in the amount of 0.5-2 wt.%. The PUVFs, with apparent densities of more than 210 kg/m3 and open-cell structures (more than 85% of open cells), showed a slow recovery to their original shape after deformation when the pressure force was removed. They were also characterized by a tensile strength in the range of 156-264 kPa, elongation at break of 310-510%, hardness of 8.1-23.1 kPa, and a high comfort factor of 3.1-7.1. The introduction of biopolyols into the polyurethane system resulted in changes in sound intensity levels of up to 31.45%, while the addition of fillers resulted in changes in sound intensity levels of up to 13.81%.

Auditory localization: a comprehensive practical review.

Auditory localization is a fundamental ability that allows to perceive the spatial location of a sound source in the environment. The present work aims to provide a comprehensive overview of the mechanisms and acoustic cues used by the human perceptual system to achieve such accurate auditory localization. Acoustic cues are derived from the physical properties of sound waves, and many factors allow and influence auditory localization abilities. This review presents the monaural and binaural perceptual mechanisms involved in auditory localization in the three dimensions. Besides the main mechanisms of Interaural Time Difference, Interaural Level Difference and Head Related Transfer Function, secondary important elements such as reverberation and motion, are also analyzed. For each mechanism, the perceptual limits of localization abilities are presented. A section is specifically devoted to reference systems in space, and to the pointing methods used in experimental research. Finally, some cases of misperception and auditory illusion are described. More than a simple description of the perceptual mechanisms underlying localization, this paper is intended to provide also practical information available for experiments and work in the auditory field.

Determination of the absorbed acoustic power of longitudinal vibrations by measuring their amplitude in a chosen area of the waveguide system outside the load.

The way of determining the acoustic power of longitudinal ultrasonic vibrations going into the load by measuring the amplitude of longitudinal displacements using an electrodynamic sensor installed near the surface of the waveguide rod is considered. Two possibilities of using the developed method of measurement are analyzed in detail. One of them is based on the registration of the value of longitudinal displacements at the constant position of the electrodynamic sensor in two different states of the ultrasound system: with the load disconnected and after the load is connected, i.e. it uses two measurements at different moments of time, when the states of the system differ from each other. Another way uses two measurements of the amplitude of longitudinal oscillations at two chosen points of the oscillatory system, made at the same time. Formulas have been obtained that make it possible to determine the power entering the load from the measured values and other known values of the system parameters. The role of errors, both in the readings of the sensor and in determining its location on the oscillating system, on the accuracy of calculating the value of the power of the ultrasonic oscillations that went into the load is analyzed.

Cepstral Analysis of Voice in Patients With Temporomandibular Disorders.

OBJECTIVES: This study aimed to assess the voice quality of patients with temporomandibular disorders (TMDs) compared with healthy subjects using cepstral analysis and investigate the relationship between the TMD severity and the values of cepstral analysis. METHODS: Subjects who met the inclusion criteria completed a general health questionnaire and the Fonseca Anamnestic Index. Patients who had TMDs with FAI were subjected to an examination based on the Diagnostic Criteria for Temporomandibular Disorders. The final sample included 65 subjects, 31 TMDs patients (with a mean age ± standard deviation of 36.64 ± 13.67 years), and 34 healthy individuals in the control group (with a mean age ± standard deviation of 30.35 ± 7.78 years). Cepstral Peak Prominence (CPP) and Smoothened Cepstral Peak Prominence (CPPS) of a sustained vowel and connected speech were computed using Praat software. RESULTS: TMD patients indicated lower cepstral values and lower voice quality compared to the control group. Significant differences were found between TMD and control groups for all cepstral parameters (P < .001) and cepstral measurements showed a moderate to strong negative correlation with TMD severity (P < .001, rho = -0.57 to -0.88). CONCLUSION: The outcomes of the present study indicate that cepstral analysis can accurately distinguish the reduced voice quality of TMD patients from normal voice.

Current developments in elastic and acoustic metamaterials science.

The concept of metamaterial recently emerged as a new frontier of scientific research, encompassing physics, materials science and engineering. In a broad sense, a metamaterial indicates an engineered material with exotic properties not found in nature, obtained by appropriate architecture either at macro-scale or at micro-/nano-scales. The architecture of metamaterials can be tailored to open unforeseen opportunities for mechanical and acoustic applications, as demonstrated by an impressive and increasing number of studies. Building on this knowledge, this theme issue aims to gather cutting-edge theoretical, computational and experimental studies on elastic and acoustic metamaterials, with the purpose of offering a wide perspective on recent achievements and future challenges. This article is part of the theme issue 'Current developments in elastic and acoustic metamaterials science (Part 1)'.

Design and experimental validation of a finite-size labyrinthine metamaterial for vibro-acoustics: enabling upscaling towards large-scale structures.

In this article, we present the design and experimental validation of a labyrinthine metamaterial for vibro-acoustic applications. Based on a two-dimensional unit cell, different designs of finite-size metamaterial specimens in a sandwich configuration including two plates are proposed. The design phase includes an optimization based on Bloch-Floquet analysis with the aims of maximizing the band gap and extruding the specimens in the third dimension while keeping the absorption properties almost unaffected. By manufacturing and experimentally testing finite-sized specimens, we assess their capacity to mitigate vibrations in vibro-impact tests. The experiments confirm a band gap in the low- to mid-frequency range. Numerical models are employed to validate the experiments and to examine additional vibro-acoustic load cases. The metamaterial's performances are compared with benchmark solutions, usually employed for noise and vibration mitigation, showing a comparable efficacy in the band gap region. To eventually improve the metamaterial's performance, we optimize its interaction with the air and test different types of connections between the metamaterial and the homogeneous plates. This finally leads to metamaterial samples largely exceeding the benchmark performances in the band gap region and reveals the potential of interfaces for performance optimization of composed structures.This article is part of the theme issue 'Current developments in elastic and acoustic metamaterials science (Part 1)'.

Differences in male Aedes aegypti and Aedes albopictus hearing systems facilitate recognition of conspecific female flight tones.

When Aedes albopictus mosquitoes invade regions predominated by Aedes aegypti, either the latter can be displaced or the species can coexist, with potential consequences on disease transmission. Males from both species identify females by listening for her flight sounds. Comparing male hearing systems may provide insight into how hearing could prevent interspecific mating. Here, we show that species-specific differences in female wing beat frequencies are reflected in differences in male ear mechanical tuning frequencies and sound response profiles. Though Aedes albopictus males are attracted to sound, they do not readily display abdominal bending, unlike Aedes aegypti. We observed interspecific differences in male ear mechanical, but not electrical, tuning, suggesting a conserved primary auditory processing pathway. Our work suggests a potential role for hearing in the premating isolation of Aedes aegypti and Aedes albopictus, with implications for predicting future dynamics in their sympatric relationships and our understanding of mosquito acoustic communication.

A Chaotic Approach to Glottal Gap Voice.

OBJECTIVE: Airway glottic insufficiency, or glottal gap, may lead to a breathy voice quality. It is hypothesized that a glottal gap may be a source of nonlinearity in speech production. This study aims to gain a chaotic and acoustic profile of glottal gap voice provided by phonation of excised larynges subjected to the insertion of a metal shim in the posterior glottis. STUDY DESIGN: Nonrandomized quasi-experimental study. METHODS: Posterior glottal gap varied from 0 to 3.5 mm in 0.5 mm intervals. Each treatment was investigated independently in a sample population of eight excised canine larynges. Phonation of the larynges for each treatment was recorded and analyzed for the cepstral peak prominence (CPP), harmonics-to-noise ratio (HNR), and correlation dimension. RESULTS: Kruskal-Wallis rank-sum tests yielded significant differences across shim groups for all parameters. Dunn-Bonferroni post-hoc tests revealed that the control group differed significantly from the 1.5, 2, 2.5, 3, and 3.5 mm groups for all metrics. Moreover, Kendall correlation tests indicated a moderately positive correlation between glottal gap size and correlation dimension, a moderately negative correlation between glottal gap size and CPP and between glottal gap size and the HNR. CONCLUSIONS: Glottic insufficiency provides a source of nonlinearity in phonation. Nonlinear dynamic analysis provides quantitative insight into glottal gap voice. This study encourages future studies to further evaluate the relationship between glottal gap and correlation dimension.

A Smart, Data-Driven Approach to Qualify Additively Manufactured Steel Samples for Print-Parameter-Based Imperfections.

With additive manufacturing (AM) processes such as Wire Arc Additive Manufacturing (WAAM), components with complex shapes or with functional properties can be produced, with advantages in the areas of resource conservation, lightweight construction, and load-optimized production. However, proving component quality is a challenge because it is not possible to produce 100% defect-free components. In addition to this, statistically determined fluctuations in the wire quality, gas flow, and their interaction with process parameters result in a quality of the components that is not 100% reproducible. Complex testing procedures are therefore required to demonstrate the quality of the components, which are not cost-effective and lead to less efficiency. As part of the project "3DPrintFEM", a sound emission analysis is used to evaluate the quality of AM components. Within the scope of the project, an approach was being developed to determine the quality of an AM part dependent not necessarily on its geometry. Samples were produced from WAAM, which were later cut and milled to precision. To determine the frequencies, the samples were put through a resonant frequency test (RFM). The unwanted modes were then removed from the spectrum produced by the experiments by comparing it with FEM simulations. Later, defects were introduced in experimental samples in compliance with the ISO 5817 guidelines. In order to create a database of frequencies related to the degree of the sample defect, they were subjected to RFM. The database was further augmented through frequencies from simulations performed on samples with similar geometries, and, hence, a training set was generated for an algorithm. A machine-learning algorithm based on regression modelling was trained based on the database to sort samples according to the degree of flaws in them. The algorithm's detectability was evaluated using samples that had a known level of flaws which forms the test dataset. Based on the outcome, the algorithm will be integrated into an equipment developed in-house to monitor the quality of samples produced, thereby having an in-house quality assessment routine. The equipment shall be less expensive than conventional acoustic equipment, thus helping the industry cut costs when validating the quality of their components.

Urban network noise control based on road grade optimization considering comprehensive traffic environment benefit.

A double-decision optimization model based on the road grade optimization strategy and considered comprehensive traffic environment benefit is proposed to control the traffic noise. The upper-level model maximizes the comprehensive traffic environment benefit, including network noise emission and traffic efficiency. Adjusting the emphasis on noise optimization benefits and traffic efficiency in road network planning through setting weights. The lower-level resolves the question of network traffic flow assignment using a stochastic user-equilibrium model. The increase of traffic environment demand, network noise emissions decrease and travel time rises. In the case, with a low environmental requirement (weighting with 1.1), the sound pressure emission of the network decreases by 9.23% with only a 4.01% increase in travel time. Under the high environmental requirement (weighting with 0.2), the sound pressure decreases by 26.8%, but the travel time rises by as high as 30.9%. The network is optimized towards road grade degradation and is the first to optimize the arterial roads. In addition, it is found that the influence of speed on traffic noise is greater than that of traffic volume through case validation. This method proposing traffic noise optimization strategies at the road network planning level provides technical support for the proactive governance of traffic noise pollution and the improvement of traffic sound environment quality.

Machine-learning based detection of marine mammal vocalizations in snapping-shrimp dominated ambient noise.

Passive acoustics is an effective method for monitoring marine mammals, facilitating both detection and population estimation. In warm tropical waters, this technique encounters challenges due to the high persistent level of ambient impulsive noise originating from the snapping shrimp present throughout this region. This study presents the development and application of a neural-network based detector for marine-mammal vocalizations in long term acoustic data recorded by us at ten locations in Singapore waters. The detector's performance is observed to be impeded by the high shrimp noise activity. To counteract this, we investigate several techniques to improve detection capabilities in shrimp noise including the use of simple nonlinear denoisers and a machine-learning based denoiser. These are shown to enhance the detection performance significantly. Finally, we discuss some of the vocalizations detected over three years of our acoustic recorder deployments using the robust detectors developed.

Impact of Audio Data Compression on Feature Extraction for Vocal Biomarker Detection: Validation Study.

BACKGROUND: Vocal biomarkers, derived from acoustic analysis of vocal characteristics, offer noninvasive avenues for medical screening, diagnostics, and monitoring. Previous research demonstrated the feasibility of predicting type 2 diabetes mellitus through acoustic analysis of smartphone-recorded speech. Building upon this work, this study explores the impact of audio data compression on acoustic vocal biomarker development, which is critical for broader applicability in health care. OBJECTIVE: The objective of this research is to analyze how common audio compression algorithms (MP3, M4A, and WMA) applied by 3 different conversion tools at 2 bitrates affect features crucial for vocal biomarker detection. METHODS: The impact of audio data compression on acoustic vocal biomarker development was investigated using uncompressed voice samples converted into MP3, M4A, and WMA formats at 2 bitrates (320 and 128 kbps) with MediaHuman (MH) Audio Converter, WonderShare (WS) UniConverter, and Fast Forward Moving Picture Experts Group (FFmpeg). The data set comprised recordings from 505 participants, totaling 17,298 audio files, collected using a smartphone. Participants recorded a fixed English sentence up to 6 times daily for up to 14 days. Feature extraction, including pitch, jitter, intensity, and Mel-frequency cepstral coefficients (MFCCs), was conducted using Python and Parselmouth. The Wilcoxon signed rank test and the Bonferroni correction for multiple comparisons were used for statistical analysis. RESULTS: In this study, 36,970 audio files were initially recorded from 505 participants, with 17,298 recordings meeting the fixed sentence criteria after screening. Differences between the audio conversion software, MH, WS, and FFmpeg, were notable, impacting compression outcomes such as constant or variable bitrates. Analysis encompassed diverse data compression formats and a wide array of voice features and MFCCs. Wilcoxon signed rank tests yielded P values, with those below the Bonferroni-corrected significance level indicating significant alterations due to compression. The results indicated feature-specific impacts of compression across formats and bitrates. MH-converted files exhibited greater resilience compared to WS-converted files. Bitrate also influenced feature stability, with 38 cases affected uniquely by a single bitrate. Notably, voice features showed greater stability than MFCCs across conversion methods. CONCLUSIONS: Compression effects were found to be feature specific, with MH and FFmpeg showing greater resilience. Some features were consistently affected, emphasizing the importance of understanding feature resilience for diagnostic applications. Considering the implementation of vocal biomarkers in health care, finding features that remain consistent through compression for data storage or transmission purposes is valuable. Focused on specific features and formats, future research could broaden the scope to include diverse features, real-time compression algorithms, and various recording methods. This study enhances our understanding of audio compression's influence on voice features and MFCCs, providing insights for developing applications across fields. The research underscores the significance of feature stability in working with compressed audio data, laying a foundation for informed voice data use in evolving technological landscapes.

Relação entre meditação, regulação emocional e expressão vocal: estudo de intervenção / Relación entre meditación, regulación emocional y expresión vocal: estudio de intervención / The relationship between meditation, emotional regulation and vocal expression: interventional study

Introdução: A voz é um indicador de estados emocionais, influenciada por fatores como o tônus vagal, a respiração e a variabilidade da frequência cardíaca. O estudo explora esses fatores e a relação com a regulação emocional e a prática meditativa como técnica de autorregulação. Objetivo: Investigar a diferença nas características vocais e na variação da frequência cardíaca em meditadores experientes (EM) e novatos (NM) antes e depois de uma prática meditativa e em não praticantes de meditação ­ grupo controle (CG), antes e depois de um teste controle. Métodos: Estudo quase-fatorial 3 x 2. Três grupos foram avaliados (meditadores experientes EM; meditadores novatos NM; e grupo controle CG, não praticantes de meditação) em dois momentos da manipulação experimental ­ antes e depois de uma sessão meditativa para praticantes de meditação, e antes e depois de uma tarefa de busca de palavras para o grupo controle. A frequência fundamental, jitter, shimmer, relação harmônico-ruído e o primeiro (F1), o segundo (F2) e terceiro (F3) formantes da vogal [a]; a variação da frequência cardíaca (SDNN, RMSSD, LF/HF, SD1 and SD2); estado de ansiedade e autopercepção vocal, foram investigados, antes e após a intervenção. Resultados: O grupo EM alcançou ótimo relaxamento do trato vocal. Os grupos NM e CG apresentaram mudanças em F1. Prática meditativa, de longa duração, está associado com grande diferença em F3, SDNN e SD2 na variação da frequência cardíaca. Conclusão: Os resultados sugerem que prática meditativa influencia a expressão vocal e reação emocional, e que a experiência em prática meditativa favorece esta relação. (AU)

Introduction: The voice is an indicator of emotional states, influenced by factors such as vagal tone, breathing and heart rate variability. This study explores these factors and their relationship with emotional regulation and meditative practice as a self-regulation technique. Purpose: To investigate the difference in vocal characteristics and heart rate variability in experienced (EM) and novice (NM) meditators before and after a meditation practice and in non-meditators - control group (CG), before and after a control test. Methods: 3 x 2 quasi-factorial study. Three groups were evaluated (experienced meditators EM; novice meditators NM; and control group CG, non-meditators) at two points in the experimental manipulation - before and after a meditation session for meditators, and before and after a word search task for the control group. The fundamental frequency, jitter, shimmer, harmonic-to-noise ratio and the first (F1), second (F2) and third (F3) formants of the vowel [a]; heart rate variation (SDNN, RMSSD, LF/HF, SD1 and SD2); anxiety state and vocal self-perception, were investigated, before and after the intervention. Results: The EM group achieved optimal vocal tract relaxation. The NM and CG groups showed changes in F1. Long-term meditative practice was associated with a large difference in F3, SDNN and SD2 in heart rate variation. Conclusion: The results suggest that meditation practice influences vocal expression and emotional reaction, and that experience in meditation practice favors this relationship. (AU)

Introducción: La voz es un indicador de los estados emocionales, influida por factores como el tono vagal, la respiración y la variabilidad de la frecuencia cardiaca. Este estudio explora estos factores y su relación con la regulación emocional y la práctica de la meditación. Objetivo: Investigar la diferencia en las características vocales y variabilidad de la frecuencia cardiaca en meditadores experimentados (EM) y novatos (NM) antes y después de una práctica de meditación y en no meditadores - grupo control (GC), antes y después de una prueba control. Métodos: Estudio cuasi-factorial 3 x 2. Se evaluaron tres grupos (meditadores experimentados EM; meditadores novatos NM; y grupo control CG, no meditadores) en dos momentos - antes y después de una sesión de meditación para los meditadores, y antes y después de una tarea de búsqueda de palabras para el grupo control. Se investigaron la frecuencia fundamental, jitter, shimmer, relación armónico-ruido y los formantes primero (F1), segundo (F2) y tercero (F3) de la vocal [a]; la variación de la frecuencia cardiaca (SDNN, RMSSD, LF/HF, SD1 y SD2); el estado de ansiedad y autopercepción vocal, antes y después de la intervención. Resultados: El grupo EM consiguió una relajación óptima del tracto vocal. Los grupos NM y CG mostraron cambios en F1. La práctica de meditación a largo plazo se asocia con una gran diferencia en F3, SDNN y SD2 en la variación de la frecuencia cardiaca. Conclusión: Los resultados sugieren que la práctica de meditación influye en la expresión vocal y reacción emocional. (AU)