scholarly journals Stabilometric changes due to exposure to firearm noise in the Brazilian Army

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Luciana Dias Bernardo ◽  
Eduardo Mendonça Scheeren ◽  
Runer Augusto Marson ◽  
Eduardo Borba Neves
Keyword(s):  
Sound Pressure ◽  
Motor Task ◽  
The Body ◽  
Body Motion ◽  
Median Frequency ◽  
Cross Sectional ◽  
Total Displacement ◽  
Perceived Difficulty ◽  
Difficulty Scale ◽  
High Sound

Success in precision activities such as shooting depends on the subtle control of body motion. To analyze the influence on stabilometric signal responses for the motor task of aiming a pistol with different cognitive demands and levels of exposure to high sound pressure in Brazilian Army personnel. This cross-sectional analytical study used stabilometry to quantify the behavior of the body during motor, cognitive, and auditory tasks. Twenty-five volunteers recruited to participate in the study completed a questionnaire, underwent anthropometric evaluation and cinemetry, and scored the perceived difficulty during exposure to a sound pressure of 132 dB while using protective equipment. A significant increase in the displacement (p=0,02), anteroposterior amplitude (p=0,01), anteroposterior velocity (p=0,01), and the perceived difficulty scale (p=0,03) between Situation 1 (aiming without other cognitive action or environmental noise) and Situation 3 (shooting noise and progressive counting) was confirmed. number of shots heard). Correlation between the perceived difficulty scale and the variables of displacement (p=0,01), anteroposterior amplitude (p=0,01), area (p=0,006) and anteroposterior mean frequency (p=0,01) were observed. The accuracy of aiming events correlated with the median lateral median frequency (p=0,02). Stabilometric signals demonstrated increased total displacement, anteroposterior amplitude, and anteroposterior velocity in the presence of high sound pressure levels. These results indicate the need for future studies to investigate the underlying mechanisms of possible vestibular damage induced by noise.  

The Sound Environment of the Foetal Sheep

Behaviour ◽  
1982 ◽  
Vol 81 (2-4) ◽  
pp. 296-315 ◽  
Author(s):  
B.A. Baldwin ◽  
B.C.J. Moore ◽  
Sally E. Armitage ◽  
J. Toner ◽  
Margaret A. Vince
Keyword(s):  
Sound Pressure ◽  
Body Wall ◽  
Low Frequency ◽  
Sound Level ◽  
The Body ◽  
Human Foetus ◽  
Low Frequencies ◽  
Sound Environment ◽  
High Sound ◽  
Foetal Lamb

AbstractThe sound environment of the foetal lamb was recorded using a hydrophone implanted a few weeks before term in a small number of pregnant ewes. It was implanted inside the amniotic sac and sutured loosely to the foetal neck, to move with the foetus. Results differ from those reported earlier for the human foetus: sounds from the maternal cardiovascular system were picked up only rarely, at very low frequencies and at sound pressures around, or below, the human auditory threshold. Other sounds from within the mother occurred intermittently and rose to a high sound pressure only at frequencies above about 300 Hz. Sounds from outside the mother were picked up by the implanted hydrophone when the external sound level rose above 65-70 dB SPL, and the attenuation in sound pressure was rarely more than 30 dB and, especially at low frequencies, usually much less. However, attenuation due to the transmission of sound through the body wall and other tissues tended to change from time to time. It is concluded that the foetal lamb's sound environment consists of (1) intermittent low frequency sounds associated largely with the ewe's feeding and digestive processes and (2) sounds such as vocalisations from the flock, human voices and other sounds from outside the mother.

scholarly journals Four-Poles Parameter of an Elliptical Cavity Having the Outlet on the Body

2020 ◽  
Vol 5 (7) ◽  
pp. 763-766
Author(s):  
Yuya Nishimura ◽  
Sohei Nishimura
Keyword(s):  
Wave Equations ◽  
Sound Pressure ◽  
Elliptic Cylinder ◽  
The Body ◽  
Noise Characteristic ◽  
Acoustic System ◽  
Cross Sectional ◽  
Elliptical Cavity ◽  
Input Side ◽  
In Series

This paper deals with the computation of the four-poles parameter of a thin elliptic cylinder in which the output is fitted to the side that is perpendicular to the input side. The four-poles parameter is based on the sound pressure calculated by solving the wave equations, with the assumption that the loss can be ignored. The four-poles parameter is widely used to estimate the noise characteristic for the acoustic system which are composed of several elements of various cross-sectional areas, various shape connected in series.

scholarly journals Rigid Foot Soles Improve Balance in Beam Walking

2019 ◽  
Author(s):  
Meghan E. Huber ◽  
Enrico Chiovetto ◽  
Martin Giese ◽  
Dagmar Sternad
Keyword(s):  
Degrees Of Freedom ◽  
Motor Task ◽  
Beam Width ◽  
Mechanical Effect ◽  
The Body ◽  
Body Motion ◽  
Whole Body ◽  
Support Surface ◽  
Narrow Beam ◽  
Skill Levels

ABSTRACTMaintaining balance while walking on a narrow beam is a challenging motor task. This is presumably because the foot’s ability to exert torque on the support surface is limited by the beam width. Still, the feet serve as a critical interface between the body and the external environment, and it is unclear how the mechanical properties of the feet affect balance. Here we examined how restricting the degrees of freedom of the feet influenced balance behavior during beam walking. We recorded whole-body joint kinematics of subjects with varying skill levels as they walked on a narrow beam with and without wearing flat, rigid soles on their feet. We computed changes in whole-body motion and angular momentum across these conditions. Results showed that wearing rigid soles improved balance in the beam walking task, but that practice with rigid soles did not affect or transfer to task performance with bare feet. The absence of any after-effect suggested that the improved balance from constraining the foot was the result of a mechanical effect rather than a change in neural strategy. Though wearing rigid soles can be used to assist balance, there appear to be limited training or rehabilitation benefits from wearing rigid soles.

scholarly journals Bass Extension of Microspeaker System on Mobile Device

2018 ◽  
Vol 35 (4) ◽  
pp. 487-498
Author(s):  
J. R. Chang ◽  
C. N. Wang
Keyword(s):  
Mobile Device ◽  
Sound Pressure ◽  
Cross Sectional ◽  
Resonant Coupling ◽  
Chamber Volume ◽  
Free Air ◽  
Acoustic Load ◽  
Extended Range ◽  
High Sound ◽  
Acceptable Agreement

ABSTRACTThis study provides a solution for the bass extension of a microspeaker system in a mobile device that involves using a resonant combination of a front chamber and a rectangular, long, pipe-shaped port. The efficient resonant coupling of the microspeaker system to the acoustic load in this structure enables a microspeaker with modest cone displacement to achieve a high sound pressure level (SPL) and bass extension below the resonance of the microspeaker in free air, and the total dimensions of the structure are minimized. A combination of electro-mechanic-acoustic and finite element methods was applied to determine the SPL and bass extension levels for mobile devices. Simulation results show acceptable agreement with experimental results. A suitable extended-range microspeaker system was applied in a 10 inch tablet. The audio frequency response could be extended from 630 to 300 Hz with the greatest loudness. As much as possible add low bound frequency extension to make the article more clear. Finally, five cases of parameter settings for the front chamber volume, rear chamber volume, rectangular pipe-shaped port, cross-sectional area, and opening area were studied. The results can be applied for optimizing a suitable extended-range microspeaker system.

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

Personal Audio System: Hearing Symptoms, Habits, and Sound Pressure Levels Measured in Real Ear and a Manikin

2020 ◽  
Vol 63 (6) ◽  
pp. 2016-2026
Author(s):  
Tamara R. Almeida ◽  
Clayton H. Rocha ◽  
Camila M. Rabelo ◽  
Raquel F. Gomes ◽  
Ivone F. Neves-Lobo ◽  
...  
Keyword(s):  
Sound Pressure ◽  
Daily Basis ◽  
Cross Sectional Study ◽  
Normal Hearing ◽  
Chi Square ◽  
Cross Sectional ◽  
The Real ◽  
Significant Difference ◽  
Sound Pressure Levels ◽  
Audio System

Purpose The aims of this study were to characterize hearing symptoms, habits, and sound pressure levels (SPLs) of personal audio system (PAS) used by young adults; estimate the risk of developing hearing loss and assess whether instructions given to users led to behavioral changes; and propose recommendations for PAS users. Method A cross-sectional study was performed in 50 subjects with normal hearing. Procedures included questionnaire and measurement of PAS SPLs (real ear and manikin) through the users' own headphones and devices while they listened to four songs. After 1 year, 30 subjects answered questions about their usage habits. For the statistical analysis, one-way analysis of variance, Tukey's post hoc test, Lin and Spearman coefficients, the chi-square test, and logistic regression were used. Results Most subjects listened to music every day, usually in noisy environments. Sixty percent of the subjects reported hearing symptoms after using a PAS. Substantial variability in the equivalent music listening level (Leq) was noted ( M = 84.7 dBA; min = 65.1 dBA, max = 97.5 dBA). A significant difference was found only in the 4-kHz band when comparing the real-ear and manikin techniques. Based on the Leq, 38% of the individuals exceeded the maximum daily time allowance. Comparison of the subjects according to the maximum allowed daily exposure time revealed a higher number of hearing complaints from people with greater exposure. After 1 year, 43% of the subjects reduced their usage time, and 70% reduced the volume. A volume not exceeding 80% was recommended, and at this volume, the maximum usage time should be 160 min. Conclusions The habit of listening to music at high intensities on a daily basis seems to cause hearing symptoms, even in individuals with normal hearing. The real-ear and manikin techniques produced similar results. Providing instructions on this topic combined with measuring PAS SPLs may be an appropriate strategy for raising the awareness of people who are at risk. Supplemental Material https://doi.org/10.23641/asha.12431435

Influence of the Acoustic Reflex on Vowel Recognition

1986 ◽  
Vol 29 (3) ◽  
pp. 420-424 ◽  
Author(s):  
Michael Dorman ◽  
Ingrid Cedar ◽  
Maureen Hannley ◽  
Marjorie Leek ◽  
Julie Mapes Lindholm
Keyword(s):  
Auditory System ◽  
Sound Pressure ◽  
Dynamic Range ◽  
Recognition Accuracy ◽  
Pressure Level ◽  
Acoustic Reflex ◽  
The Poor ◽  
Stapedial Reflex ◽  
Vowel Recognition ◽  
High Sound

Computer synthesized vowels of 50- and 300-ms duration were presented to normal-hearing listeners at a moderate and high sound pressure level (SPL). Presentation at the high SPL resulted in poor recognition accuracy for vowels of a duration (50 ms) shorter than the latency of the acoustic stapedial reflex. Presentation level had no effect on recognition accuracy for vowels of sufficient duration (300 ms) to elicit the reflex. The poor recognition accuracy for the brief, high intensity vowels was significantly improved when the reflex was preactivated. These results demonstrate the importance of the acoustic reflex in extending the dynamic range of the auditory system for speech recognition.

PEMBELAJARAN SIMULASI PENCITRAAN CT DENGAN MENGGUNAKAN PRINSIP REKONSTRUKSI CITRA DALAM SOFTWARE MATLAB

2015 ◽  
Vol 8 (3) ◽  
pp. 161
Author(s):  
Samuel Gideon
Keyword(s):  
Image Reconstruction ◽  
Ct Imaging ◽  
The Body ◽  
Reconstruction Technique ◽  
Imaging Features ◽  
Back Projection ◽  
Cross Sectional ◽  
Low Contrast ◽  
Image Reconstruction Technique ◽  
Imaging Algorithms

This research was conducted as a learning alternatives for study of CT (computed tomograpghy) imaging using image reconstruction technique which are inversion matrix, back projection and filtered back projection. CT imaging can produce images of objects that do not overlap. Objects more easily distinguishable although given the relatively low contrast. The image is generated on CT imaging is the result of reconstruction of the original object. Matlab allows us to create and write imaging algorithms easily, easy to undersand and gives applied and exciting other imaging features. In this study, an example cross-sectional image recon-struction performed on the body of prostate tumors using. With these methods, medical prac-titioner (such as oncology clinician, radiographer and medical physicist) allows to simulate the reconstruction of CT images which almost resembles the actual CT visualization techniques.Keywords : computed tomography (CT), image reconstruction, Matlab

Kajian Kandungan Fe dalam Air Tanah Terhadap Kadar Ekskresi Yodium dalam Urin pada Anak Sekolah di Desa Cerme Kecamatan Panjatan Kabupaten Kulon Progo

2017 ◽  
Vol 19 (1) ◽  
pp. 7-11
Author(s):  
Vivi Linda Fristianti ◽  
Nur Hidayat ◽  
Slamet Iskandar
Keyword(s):  
Elementary School ◽  
Ground Water ◽  
School Children ◽  
Laboratory Data ◽  
Simple Random Sampling ◽  
Optimal Level ◽  
The Body ◽  
Design Data ◽  
Cross Sectional ◽  
Fe Content

Background : IDD problem is a serious problem, 33% of districts in Indonesia are endemic, 21% of endemic mild, moderate endemic 5% and 7% by weight endemic. Urine Iodine Excretion (EYU) illustrates the iodine intake of a person, because 90% of the iodine that enter the body are excreted through the urine. Blocking agents are substances certain minerals such as iron, manganese and calcium, which can bind iodine in groundwater. Objectives : This study aims to determine the relationship of Fe content in ground water sources against EYU levels in school children in the village of the District Cerme Panjatan Kulon Progo. Methods : An observational analytic research with cross sectional design. Data collection is done in May - June 2015. Location research Elementary School Cerme, District Panjatan Kulon Progo. The subjects of the study as many as 34 children in elementary school classroom Cerme 3, 4 and 5 were taken by simple random sampling. Well water and urine samples taken students then tested the iron in the Central Health Laboratory test Yogyakarta and iodine in urine in Magelang BP2GAKY Laboratory. Data analysis using Spearman Range test with significancy level : 0.05. Result : Fe content in the ground water is below the normal threshold is <0.3 mg / L. While levels EYU school children who are under the optimal level of 5.9%, the optimal level of 32.4%, and the optimum levels above 61.8% (optimal: 100 - 199μg / L). Conclusion : There was no significant relationship between the Fe content in groundwater with levels of EYU in school children in District Panjatan Kulon Progo (p = 0.447).   Keywords: Fe, EYU

Sign in / Sign up

Export Citation Format

Share Document