Acoustic and vibrational signaling in true katydid Nesoecia nigrispina: three means of sound production in the one species

The males of Mexican katydids Nesoecia nigrispina (Stal) produce calling songs and protest sounds using the same stridulatory apparatus as in most of the other Ensifera at the base of the elytra. It includes pars stridens on the upper elytron and plectrum on the lower. Calling sounds are 2−pulse series, repeated with a frequency of 2−3 per sec. Protest signals in the form of short trills from the same pulse duration males produce with tactile stimulation. The pulse repetition rate is almost three times higher than that of the calling sounds - up to 10 per sec. The frequency spectra of these signals have maxima in the band of 14−15 kHz. However, in addition to the sounds described, both males and females are capable to produce protest signals of the second type with the help of another sound apparatus, namely with the help of the wings. Insects with removed elytra are unable to produce an audible sound. Thus, the sound is produced by the friction of the wings on the elytra, but there are no specialized stridulatory structures on them. In females, in response to tactile stimulation, short clicks are recorded, which they make, apparently, by the mandibles. Vibrational signals at tremulation are emitted by individuals of both sexes during courtship and males, completing the calling signal cycle and after copulation. It is possible that vibrational signals are an additional factor in reproductive isolation in sympatric species, since the calling sound signals in representatives of the genus Nesoecia are similar and exhibit significant variability.

THE SOUND DIMENSION IN THE UPPER BASIN OF THE MIÑO RIVER (GALICIA, NW IBERIAN PENINSULA)

The sound spectrum of water configures representative marks of various environments, which define a sound heritage with scientific, cultural, emotional, sensorial and educational value. From this perspective, river environments comprise a wide spectrum of sonic resonances. This study, contextualized within the field of geo-sonority research, considers the recording and analysis of water through several samples from the upper basin of the Miño River. The objectives are to advocate for the role of sonority as part of the intangible heritage, to explore its character in the fluvial environment of inland Galicia, and to contribute to the preservation of the sonic marks of water as sounds inherent to the identity of an area. The methodology applied consists of phases of field recording, the creation of databases and of phonic analysis. Water in its sound form, from the drop rhythmically repeating to the roar of a waterfall, fills an audible sound spectrum that characterizes soundscapes. By registering, documenting, and analyzing the sounds of the water, we advance in the knowledge of the diversity of the sound environments in the river basin of the Miño River.

Device-Free Handwritten Character Recognition Method Using Acoustic Signal

In this paper, we propose a method for recognizing handwritten characters by a finger using acoustic signals. This method is carried out using a smartphone placed on a flat surface, such as a desk. Specifically, this method uses an ultrasonic wave transmitted from the smartphone, which is reflected by the finger, and an audible sound is generated when writing a handwritten character. The proposed method does not require an additional device for handwritten character recognition because it uses the microphone/speaker built into the device. Evaluation results showed that it was able to recognize 36 types of characters with an average accuracy of 77.8% in a low noise environment for 10 subjects. In addition, it was verified that combining an audible sound and an ultrasonic wave in this method achieved higher recognition accuracy than when only an audible sound or an ultrasonic wave was used.

PLoS Computational Biology Issue Image | Vol. 17(9) October 2021

The tomato flowers are characterized by possessing poricidal anthers, which restrict the exit of the pollen to a tiny opening on the apex of the anther. To extract pollen efficiently, some visiting bees grasp the anthers and quickly contracting their flight muscles, producing vibrations and an audible sound. The vibrations are transferred to the anthers, shaking and stimulating the pollen inside them to leave by the pores, a phenomenon known as floral sonication or buzz-pollination. DOI: pcbi.1009426 Image Credit: Priscila de CE1;ssia Souza AraFA;jo (co-author of the manuscript) photographed this bee visiting flowers of tomato plants grown at the experimental fields of the Federal University of ViE7;osa (Minas Gerais State, Brazil). We confirm that the image can publish under the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). The authors own the copyright for the image and confirm that agree with open Access License of PLOS Computational Biology.

PLoS Computational Biology Issue Image | Vol. 1(9) October 2021

The tomato flowers are characterized by possessing poricidal anthers, which restrict the exit of the pollen to a tiny opening on the apex of the anther. To extract pollen efficiently, some visiting bees grasp the anthers and quickly contracting their flight muscles, producing vibrations and an audible sound. The vibrations are transferred to the anthers, shaking and stimulating the pollen inside them to leave by the pores, a phenomenon known as floral sonication or buzz-pollination. DOI: pcbi.1009426 Image Credit: Priscila Souza AraFA;jo (co-author of the manuscript) photographed this bee visiting flowers of tomato plants grown at the experimental fields of the Federal University of ViE7;osa (Minas Gerais State, Brazil). We confirm that the image can publish under the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). The authors own the copyright for the image and confirm that agree with open Access License of PLOS Computational Biology.

Seeking Inspiration: Examining the Validity and Reliability of a New Smartphone Respiratory Therapy Exergame App

Background: Clinically valid and reliable simulated inspiratory sounds were required for the development and evaluation of a new therapeutic respiratory exergame application (i.e., QUT Inspire). This smartphone application virtualises incentive spirometry, a longstanding respiratory therapy technique. Objectives: Inspiratory flows were simulated using a 3 litre calibration syringe and validated using clinical reference devices. Syringe flow nozzles of decreasing diameter were applied to model the influence of mouth shape on audible sound levels generated. Methods: A library of calibrated audio inspiratory sounds was created to determine the reliability and range of inspiratory sound detection at increasing distances separating the sound source and smartphones running the app. Results: Simulated inspiratory sounds were reliably detected by the new application at higher air inflows (high, medium), using smaller mouth diameters (<25 mm) and where smartphones were held proximal (< = 5 cm) to the mouth (or at distances up to 50 cm for higher airflows). Performance was comparable for popular smartphone types and using different phone orientations (i.e., held horizontally, at 45° or 90°). Conclusions: These observations inform future application refinements, including prompts to reduce mouth diameter, increase inspiratory flow and maintain proximity to the phone to optimise sound detection. This library of calibrated inspiratory sounds offers reproducible non-human reference data suitable for development, evaluation and regression testing of a therapeutic respiratory exergame application for smartphones.

Removal of total nitrogen from wastewater by a combination of Chlorella sp. and audible sound

In developing countries, nitrogen in the traditional market wastewater is a critical environmental problem. In this study, the microalga Chlorella sp., which was isolated from wastewater, was used to remove the total nitrogen (TN) from conventional market wastewater in combination with audible sound (Vietnamese classical music). In addition, effects of sound exposure on removal efficiency at different initial cell densities were analyzed. Results revealed that music sound control demonstrates potential to improve the removal efficiency. TN removal efficiencies of 96%, 69.5%, and 4.3% were observed for treatments with Chlorella sp./audible sound, Chlorella sp., and without Chlorella sp., respectively. The significance of probability value (p-value) (&lt;0.05) on the paired sample t-test confirmed the critical role of audible sound and Chlorella sp. density on the TN removal in screening experiments. The predicted optimal conditions for TN removal were as follows: a Chlorella sp. density of 4%, an audible sound of 52.5 dB, and a cultivation time of 4.6 days. Results based on statistical analysis revealed that the quadratic models for TN removal are significant at a low p-value (&lt;0.05) and a high predicted coefficient of determination (R2 = 0.9452) value. The obtained statistical results also indicated that most of the variables are significant for the abatement of TN from market wastewater using Chlorella sp.

Study of the Optimal Waveforms for Non-Destructive Spectral Analysis of Aqueous Solutions by Means of Audible Sound and Optimization Algorithms

Acoustic analysis of materials is a common non-destructive technique, but most efforts are focused on the ultrasonic range. In the audible range, such studies are generally devoted to audio engineering applications. Ultrasonic sound has evident advantages, but also severe limitations, like penetration depth and the use of coupling gels. We propose a biomimetic approach in the audible range to overcome some of these limitations. A total of 364 samples of water and fructose solutions with 28 concentrations between 0 g/L and 9 g/L have been analyzed inside an anechoic chamber using audible sound configurations. The spectral information from the scattered sound is used to identify and discriminate the concentration with the help of an improved grouping genetic algorithm that extracts a set of frequencies as a classifier. The fitness function of the optimization algorithm implements an extreme learning machine. The classifier obtained with this new technique is composed only by nine frequencies in the (3–15) kHz range. The results have been obtained over 20,000 independent random iterations, achieving an average classification accuracy of 98.65% for concentrations with a difference of ±0.01 g/L.