A frequency-modulated audio oscillator for studying dynamic responses in the auditory system

1964 ◽  
Vol 2 (3) ◽  
pp. 311-316
Author(s):  
I. C. Whitfield ◽  
D. Hodges
Keyword(s):  
Auditory System ◽  
Dynamic Responses ◽  
Audio Oscillator

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

Evaluation of Efferent Auditory System and Hearing Quality in Parkinson's Disease: Is the Difficulty in Speech Understanding in Complex Listening Conditions Related to Neural Degeneration or Aging?

2020 ◽  
pp. 1-9
Author(s):  
Nuriye Yıldırım Gökay ◽  
Bülent Gündüz ◽  
Fatih Söke ◽  
Recep Karamert
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Auditory System ◽  
Otoacoustic Emissions ◽  
Pure Tone ◽  
Pure Tone Audiometry ◽  
Auditory Pathway ◽  
Normal Hearing ◽  
System Function ◽  
Distortion Product

Purpose The effects of neurological diseases on the auditory system have been a notable issue for investigators because the auditory pathway is closely associated with neural systems. The purposes of this study are to evaluate the efferent auditory system function and hearing quality in Parkinson's disease (PD) and to compare the findings with age-matched individuals without PD to present a perspective on aging. Method The study included 35 individuals with PD (mean age of 48.50 ± 8.00 years) and 35 normal-hearing peers (mean age of 49 ± 10 years). The following tests were administered for all participants: the first section of the Speech, Spatial and Qualities of Hearing Scale; pure-tone audiometry, speech audiometry, tympanometry, and acoustic reflexes; and distortion product otoacoustic emissions (DPOAEs) and contralateral suppression of DPOAEs. SPSS Version 25 was used for statistical analyses, and values of p < .05 were considered statistically significant. Results There were no statistically significant differences in the pure-tone audiometry thresholds and DPOAE responses between the individuals with PD and their normal-hearing peers ( p = .732). However, statistically significant differences were found between the groups in suppression levels of DPOAEs and hearing quality ( p < .05). In addition, a statistically significant and positive correlation was found between the amount of suppression at some frequencies and the Speech, Spatial and Qualities of Hearing Scale scores. Conclusions This study indicates that medial olivocochlear efferent system function and the hearing quality of individuals with PD were affected adversely due to the results of PD pathophysiology on the hearing system. For optimal intervention and follow-up, tasks related to hearing quality in daily life can also be added to therapies for PD.

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.

Classification of Acceleration Waveforms during Walking by Wavelet Transform

1997 ◽  
Vol 36 (04/05) ◽  
pp. 356-359 ◽  
Author(s):  
M. Sekine ◽  
M. Ogawa ◽  
T. Togawa ◽  
Y. Fukui ◽  
T. Tamura
Keyword(s):  
Wavelet Transform ◽  
Wavelet Analysis ◽  
Center Of Gravity ◽  
Dynamic Responses ◽  
Sequential Data ◽  
Acceleration Signal ◽  
Continuous Dynamic

Abstract:In this study we have attempted to classify the acceleration signal, while walking both at horizontal level, and upstairs and downstairs, using wavelet analysis. The acceleration signal close to the body’s center of gravity was measured while the subjects walked in a corridor and up and down a stairway. The data for four steps were analyzed and the Daubecies 3 wavelet transform was applied to the sequential data. The variables to be discriminated were the waveforms related to levels -4 and -5. The sum of the square values at each step was compared at levels -4 and -5. Downstairs walking could be discriminated from other types of walking, showing the largest value for level -5. Walking at horizontal level was compared with upstairs walking for level -4. It was possible to discriminate the continuous dynamic responses to walking by the wavelet transform.

Stochastic resonance in the peripheral auditory system

2014 ◽  
Vol 2 ◽  
pp. 417-420
Author(s):  
Florian Gomez ◽  
Stefan Martignoli ◽  
Ruedi Stoop
Keyword(s):  
Stochastic Resonance ◽  
Auditory System ◽  
Peripheral Auditory System

Control of Vibrations due to Moving Loads on Suspension Bridges

2006 ◽  
Vol 11 (3) ◽  
pp. 293-318 ◽  
Author(s):  
M. Zribi ◽  
N. B. Almutairi ◽  
M. Abdel-Rohman
Keyword(s):  
Bridge Deck ◽  
Suspension Bridge ◽  
Lyapunov Theory ◽  
Dynamic Responses ◽  
Suspension Bridges ◽  
Control Force ◽  
Moving Loads ◽  
Hydraulic Actuator ◽  
Long Span ◽  
Suspended Cables

The flexibility and low damping of the long span suspended cables in suspension bridges makes them prone to vibrations due to wind and moving loads which affect the dynamic responses of the suspended cables and the bridge deck. This paper investigates the control of vibrations of a suspension bridge due to a vertical load moving on the bridge deck with a constant speed. A vertical cable between the bridge deck and the suspended cables is used to install a hydraulic actuator able to generate an active control force on the bridge deck. Two control schemes are proposed to generate the control force needed to reduce the vertical vibrations in the suspended cables and in the bridge deck. The proposed controllers, whose design is based on Lyapunov theory, guarantee the asymptotic stability of the system. The MATLAB software is used to simulate the performance of the controlled system. The simulation results indicate that the proposed controllers work well. In addition, the performance of the system with the proposed controllers is compared to the performance of the system controlled with a velocity feedback controller.

New possibility for measuring the cortical auditory evoked potentials: the HEARLab

2014 ◽  
Vol 155 (38) ◽  
pp. 1524-1529
Author(s):  
Ádám Bach ◽  
Ferenc Tóth ◽  
Vera Matievics ◽  
József Géza Kiss ◽  
József Jóri ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Evoked Potentials ◽  
Auditory System ◽  
Hearing Aids ◽  
Pure Tone ◽  
Auditory Evoked Potentials ◽  
Normal Hearing ◽  
Speech Stimuli ◽  
Novel Method ◽  
Cortical Auditory Evoked Potentials

Introduction: Cortical auditory evoked potentials can provide objective information about the highest level of the auditory system. Aim: The purpose of the authors was to introduce a new tool, the “HEARLab” which can be routinely used in clinical practice for the measurement of the cortical auditory evoked potentials. In addition, they wanted to establish standards of the analyzed parameters in subjects with normal hearing. Method: 25 adults with normal hearing were tested with speech stimuli, and frequency specific examinations were performed utilizing pure tone stimuli. Results: The findings regarding the latency and amplitude analyses of the evoked potentials confirm previously published results of this novel method. Conclusions: The HEARLAb can be a great help when performance of the conventional audiological examinations is complicated. The examination can be performed in uncooperative subjects even in the presence of hearing aids. The test is frequency specific and does not require anesthesia. Orv. Hetil., 2014, 155(38), 1524–1529.

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