Amplitude Rise Time Research Articles

Anatomical and behavioural correlates of auditory perception in developmental dyslexia.

Developmental dyslexia is typically associated with difficulties in basic auditory processing and in manipulating speech sounds. However, the neuroanatomical correlates of auditory difficulties in developmental dyslexia (DD) and their contribution to individual clinical phenotypes are still unknown. Recent intracranial electrocorticography findings associated processing of sound amplitude rises and speech sounds with posterior and middle superior temporal gyrus (STG), respectively. We hypothesize that regional STG anatomy will relate to specific auditory abilities in DD, and that auditory processing abilities will relate to behavioral difficulties with speech and reading. One hundred and ten children (78 DD, 32 typically developing, age 7-15 years) completed amplitude rise time and speech in noise discrimination tasks. They also underwent a battery of cognitive tests. Anatomical MRI scans were used to identify regions in which local cortical gyrification complexity correlated with auditory behavior. Behaviorally, amplitude rise time but not speech in noise performance was impaired in DD. Neurally, amplitude rise time and speech in noise performance correlated with gyrification in posterior and middle STG, respectively. Furthermore, amplitude rise time significantly contributed to reading impairments in DD, while speech in noise only explained variance in phonological awareness. Finally, amplitude rise time and speech in noise performance were not correlated, and each task was correlated with distinct neuropsychological measures, emphasizing their unique contributions to DD. Overall, we provide a direct link between the neurodevelopment of the left STG and individual variability in auditory processing abilities in neurotypical and dyslexic populations.

Anatomical and behavioral correlates of auditory perception in developmental dyslexia.

Developmental dyslexia is typically associated with difficulties in basic auditory processing and in manipulating speech sounds. However, the neuroanatomical correlates of auditory difficulties in developmental dyslexia (DD) and their contribution to individual clinical phenotypes are still unknown. Recent intracranial electrocorticography findings associated processing of sound amplitude rises and speech sounds with posterior and middle superior temporal gyrus (STG), respectively. We hypothesize that regional STG anatomy will relate to specific auditory abilities in DD, and that auditory processing abilities will relate to behavioral difficulties with speech and reading. One hundred and ten children (78 DD, 32 typically developing, age 7-15 years) completed amplitude rise time and speech in noise discrimination tasks. They also underwent a battery of cognitive tests. Anatomical MRI scans were used to identify regions in which local cortical gyrification complexity correlated with auditory behavior. Behaviorally, amplitude rise time but not speech in noise performance was impaired in DD. Neurally, amplitude rise time and speech in noise performance correlated with gyrification in posterior and middle STG, respectively. Furthermore, amplitude rise time significantly contributed to reading impairments in DD, while speech in noise only explained variance in phonological awareness. Finally, amplitude rise time and speech in noise performance were not correlated, and each task was correlated with distinct neuropsychological measures, emphasizing their unique contributions to DD. Overall, we provide a direct link between the neurodevelopment of the left STG and individual variability in auditory processing abilities in neurotypical and dyslexic populations.

Amplitude rise time sensitivity in children with and without dyslexia: differential task effects and longitudinal relations to phonology and literacy.

The speech amplitude envelope carries important acoustic information required for speech intelligibility and contains sensory cues (amplitude rise times, ARTs) that play a key role in both sensory rhythm perception and neural speech encoding. Individual differences in children's sensitivity to ARTs have been related to the development of children's phonological processing skills across languages by the Temporal Sampling theory. Impaired processing of ARTs also characterises children with dyslexia. However, different ART tasks have been employed in different studies, in different languages, and at different ages. Here, we compare the sensitivity of three frequently used ART tasks (based on synthetic syllables, sine tones, and speech-shaped noise) in a longitudinal study of English-speaking children with and without dyslexia. Children's ability to discriminate rising frequency, duration, and intensity was also tested. ART discrimination in all 3 tasks was significantly inter-related, but different relations to phonology and literacy were found for different ART tasks at different ages. In particular, the often-used sine tone and speech-shaped noise ART tasks showed greater sensitivity in older children, while the synthetic syllable task (/ba/ rise) showed greater sensitivity in younger children. Sensitivity to rising frequency was also related to phonology and literacy across ages. The data are interpreted with respect to the Temporal Sampling theory of developmental dyslexia.

Neural responses to natural and enhanced speech edges in children with and without dyslexia.

Sensory-neural studies indicate that children with developmental dyslexia show impairments in processing acoustic speech envelope information. Prior studies suggest that this arises in part from reduced sensory sensitivity to amplitude rise times (ARTs or speech "edges") in the envelope, accompanied by less accurate neural encoding of low-frequency envelope information. Accordingly, enhancing these characteristics of the speech envelope may enhance neural speech processing in children with dyslexia. Here we applied an envelope modulation enhancement (EME) algorithm to a 10-min story read in child-directed speech (CDS), enhancing ARTs and also enhancing low-frequency envelope information. We compared neural speech processing (as measured using MEG) for the EME story with the same story read in natural CDS for 9-year-old children with and without dyslexia. The EME story affected neural processing in the power domain for children with dyslexia, particularly in the delta band (0.5-4 Hz) in the superior temporal gyrus. This may suggest that prolonged experience with EME speech could ameliorate some of the impairments shown in natural speech processing by children with dyslexia.

SEPIC-Based DC–DC Converter with Soft Switching Operation for Wide Conversion Operation of E-Automobiles

The article introduces a novel approach for designing a DC-to-DC converter utilizing the single-ended primary inductor converter topology for wide conversion operation in Electric Automobiles (E-Automobiles), with a focus on soft switching operation. A maximum power point tracking approach based on hierarchical multi-heuristic chicken swarm optimization is used to optimize the performance of the solar. The output of the converter is then fed into a three-phase inverter, where pulse width modulation is generated using a fuzzy logic controller (FLC). The inverted output is filtered using a low-pass filter before being supplied to the load, which is a brushless direct current motor in this case. The performance of the system is evaluated using traditional proportional-integral-derivative controllers and FLC controllers, considering parameters such as maximum amplitude (rise time), the time at which the system achieves its peak value (peak time), the time delay between input and output (delay time), the amplitude of the output voltage and current (output voltage and output current), and the discrepancy between the desired and actual values in a stable state (steady-state error). Comparative analysis indicates that the proposed design incorporating an FLC controller yields superior results compared to other approaches.

Reverse Blocking Diode Thyristor With High Di/Dt Capability for Explosive Foil Initiator Applications

High-voltage switch with high current and high current rise rate capability is important in explosive foil initiator (EFI) applications because the current with high amplitude and short rise time is necessary in order to gasify the explosive foil. In this work, reverse blocking diode thyristor (RBDT) for this application is optimally designed and fabricated. The 2-D numerical model of RBDT is first established. Based on this model, the cathode layout and the doping concentration of P base layer of the device are carefully analyzed. The cell size and the length ratio of the emitter to the short-circuit point at cathode are analyzed. Samples of RBDT are developed in our laboratory, with the blocking voltage of 1600 V. The peak current of 2400 A is acquired in the pulse discharge experiment, with a maximum current rise rate as high as 18 kA/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> , which is the highest <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{d}{i}/\text{d}{t}$ </tex-math></inline-formula> value reported for RBDT until now. This result makes the proposed RBDT a promising candidate for EFI applications.

Identification of Acoustic Emission Signatures and Their Capability to Assess the Damage of Reinforced Concrete Beam under Incremental Cyclic Loading

Acoustic emission (AE) has been widely used for damage detection and characterization in reinforced concrete (RC) structures. However, there is little work focusing on correlation of AE signatures and physical phenomena involved within the failure process of RC beams. In this paper, AE monitoring was performed on five small-scale RC beams that were subjected to an incremental cyclic loading regimen. Correlation of AE activity with in situ crack progression was performed by comparing AE signatures with a series of real-time images of crack development. Based on the combination of AE response and development of flexural and shear crack patterns, four phases named microcrack formation, macrocrack initiation, crack opening/closing, and near failure were recognizable. Meanwhile, AE cumulative energy (CE) analysis during loading and unloading demonstrated its potential for damage detection and qualification. The test results show crack initiation and propagation are accompanied with significantly greater AE activity in comparison to existing crack reopening or closing; and during the unloading step when the RC beams are near failure, the calculated CE is greater than that for initial crack appearance. In addition, AE event localization method and waveform analysis were performed to aid in identifying the source mechanisms of meaningful events. Crack propagation events were associated with burst type signals. During unloading step near failure, signals of high amplitude and long rise time are located along the reinforcement indicating a potential loss of bond as the reinforcement interacts with its surrounding concrete. The results showed that the combination of each analysis type aided in determining whether AE generated during loading/unloading of RC can be a meaningful parameter in monitoring damage of RC structures.

The relationship between basic auditory processing, prosodic sensitivity and reading in German adults

Prosodic sensitivity (PS) and phonological awareness (PA) are reading‐related predictors in children, which themselves might be affected by basic auditory processing (BAP). This study proposes a new model that considers possible relations between all three variables and reading. Skilled adult reading is examined to exclude possible developmental influences and obtain more information about mature reading. One hundred thirty‐eight German‐speaking adults (mean age: 26 years) completed three measures of BAP (frequency, intensity and amplitude rise time discrimination), two sentence‐based PS tasks, a PA task, and three word and nonword reading tasks. Structural equation modelling revealed a significant direct effect of PS on reading, a significant direct effect of BAP on PS and an indirect effect of BAP on reading via PS. The results strengthen the relevance of BAP skills and PS for reading in adults.

Neural detection of changes in amplitude rise time in infancy

Amplitude rise times play a crucial role in the perception of rhythm in speech, and reduced perceptual sensitivity to differences in rise time is related to developmental language difficulties. Amplitude rise times also play a mechanistic role in neural entrainment to the speech amplitude envelope. Using an ERP paradigm, here we examined for the first time whether infants at the ages of seven and eleven months exhibit an auditory mismatch response to changes in the rise times of simple repeating auditory stimuli. We found that infants exhibited a mismatch response (MMR) to all of the oddball rise times used for the study. The MMR was more positive at seven than eleven months of age. At eleven months, there was a shift to a mismatch negativity (MMN) that was more pronounced over left fronto-central electrodes. The MMR over right fronto-central electrodes was sensitive to the size of the difference in rise time. The results indicate that neural processing of changes in rise time is present at seven months, supporting the possibility that early speech processing is facilitated by neural sensitivity to these important acoustic cues.

A Bridge over Troubled Listening: Improving Speech-in-Noise Perception by Children with Dyslexia.

Developmental dyslexia is most commonly associated with phonological processing difficulties. However, children with dyslexia may experience poor speech-in-noise perception as well. Although there is an ongoing debate whether a speech perception deficit is inherent to dyslexia or acts as an aggravating risk factor compromising learning to read indirectly, improving speech perception might boost reading-related skills and reading acquisition. In the current study, we evaluated advanced speech technology as applied in auditory prostheses, to promote and eventually normalize speech perception of school-aged children with dyslexia, i.e., envelope enhancement (EE). The EE strategy automatically detects and emphasizes onset cues and consequently reinforces the temporal structure of the speech envelope. Our results confirmed speech-in-noise perception difficulties by children with dyslexia. However, we found that exaggerating temporal "landmarks" of the speech envelope (i.e., amplitude rise time and modulations)-by using EE-passively and instantaneously improved speech perception in noise for children with dyslexia. Moreover, the benefit derived from EE was large enough to completely bridge the initial gap between children with dyslexia and their typical reading peers. Taken together, the beneficial outcome of EE suggests an important contribution of the temporal structure of the envelope to speech perception in noise difficulties in dyslexia, providing an interesting foundation for future intervention studies based on auditory and speech rhythm training.

Cross-linguistic contributions of acoustic cues and prosodic awareness to first and second language vocabulary knowledge.

Several studies have revealed that prosody contributes to reading acquisition. However, the relation between awareness of prosodic patterns and different facets of language ability (e.g., vocabulary knowledge) in school-age children remains unclear. This study measured awareness of prosodic patterns using non-speech and speech stimuli. Hierarchical regression equations were computed to examine links among auditory cues (e.g., amplitude rise time, pitch contour and interval), language-specific prosodic awareness and children's vocabulary knowledge in Mandarin as a first language (L1) and English as a second language (L2) after controlling for age and nonverbal IQ. Results revealed that (1) amplitude envelope rise time discrimination predicted Mandarin L1 and English L2 vocabulary knowledge, (2) Mandarin tone perception and rhyme awareness did not predict Mandarin L1 vocabulary and (3) English rhyme awareness better predicted English L2 vocabulary than did stress production. Our findings suggest that (1) amplitude rise time, which signals syllable boundaries, is a cross-linguistic predictor of vocabulary knowledge and (2) the development of English L2 vocabulary may depend on phonological more than prosodic awareness.

Use of duration and rise time cues in the labelling of affricate and fricative speech sounds by children with reading difficulties

Differentiation of speech is predictable from abilities to discriminate the speed at which a sound reaches its optimum amplitude (rise time). This study investigated whether rise time identification of an affricate–fricative continuum would be impacted upon by dyslexia. Children between 10 and 14 years old identified sounds along a continuum of fricative to affricate sounds (cha–sha continuum), using a novel automated learning rise time identification task. Those with higher dyslexia likelihoods (measured by the Dyslexia Screening Test – Secondary), and poor reading scores (measured by the British Abilities Scales), showed a difference in rise time identification; greater distances between rise times were needed for those with a high risk of dyslexia to recognise fricative–affricate differences than for controls. These results were not impacted upon by IQ scores.

AN EAR FOR LANGUAGE

ABSTRACTThis study tested whether individual sensitivity to an auditory perceptual cue called amplitude rise time (ART) facilitates novel word learning. Forty adult native speakers of Polish performed a perceptual task testing their sensitivity to ART, learned associations between nonwords and pictures of common objects, and were subsequently tested on their knowledge with a picture recognition (PR) task. In the PR task participants heard each nonword, followed either by a congruent or incongruent picture, and had to assess if the picture matched the nonword. Word learning efficiency was measured by accuracy and reaction time on the PR task and modulation of the N300 ERP. As predicted, participants with greater sensitivity to ART showed better performance in PR suggesting that auditory sensitivity indeed facilitates learning of novel words. Contrary to expectations, the N300 was not modulated by sensitivity to ART suggesting that the behavioral and ERP measures reflect different underlying processes.

On using converging shock waves for pressure amplification in shock tubes

While conventional shock tubes have a distinct advantage in dynamic calibration methods due to their inherent capability to generate pressure pulses of desired amplitude and fast rise time, they are limited to the lower levels of the pressure amplitude realization range (≤7 MPa). With the increasing need for a traceable dynamic calibration standard across wider pressure ranges, a novel technique using converging shock waves is demonstrated in this work that pushes the upper limit of the standard shock tube into the medium-high pressure range. The experiments are conducted in the shock tube facility equipped with a test section that smoothly transforms the incident plane shock into a spherical shock wave that converges, accelerates and thereby amplifies its strength many folds. The experimentally recorded pressure traces are compared with numerical simulations performed by an in-house code. Using this technique, pressure pulses with peak amplitudes in the range of 30–40 MPa, with 3.4% uncertainty based on numerical reference profile, were realized in the test section with nominal usage of resources.

PTF14jg: The Remarkable Outburst and Post-burst Evolution of a Previously Anonymous Galactic Star

Abstract We report the outbursting source PTF 14jg, which, prior to the onset of its late 2013 eruption, was a faint, unstudied, and virtually uncataloged star. The salient features of the PTF 14jg outburst are (i) projected location near the W4 H ii region and radial velocity consistent with physical association; (ii) a light curve that underwent an ∼6–7 mag optical (R-band) through mid-infrared (L-band) brightening on a timescale of a few months, peaked and then faded by ∼3 mag, but plateaued still &gt;3.5 mag above quiescence by ∼8 months post-peak, lasting to at least 4 yr after eruption; (iii) strong outflow signatures with velocities reaching −530 ; (iv) a low-gravity and broad (∼100–150 FWHM) optical absorption-line spectrum that systematically changes its spectral type with wavelength; (v) lithium; and (vi) ultraviolet and infrared excess. We tentatively identify the outburst as exhibiting characteristics of a young star FU Ori event. However, the burst would be unusually hot, with an absorption spectrum exhibiting high-excitation (∼11,000–15,000 K) lines in the optical and no evidence of CO in the near-infrared, in addition to exhibiting an unusual light curve. We thus also consider alternative scenarios—including various forms of novae, nuclear-burning instabilities, massive star events, and mergers—finding them all inferior to the atypically hot FU Ori star classification. The source eventually may be interpreted as a new category of young star outburst with a larger amplitude and shorter rise time than most FU Ori–like events.

Atypical neural processing of rise time by adults with dyslexia

In recent studies phonological deficits in dyslexia are related to a deficit in the synchronization of neural oscillations to the dynamics of the speech envelope. The temporal features of both amplitude modulations and rise times characterize the speech envelope. Previous studies uncovered the inefficiency of the dyslexic brain to follow different amplitude modulations in speech. However, it remains to be investigated how the envelope's rise time mediates this neural processing. In this study we examined neural synchronization in students with and without dyslexia using auditory steady-state responses at theta, alpha, beta and low-gamma range oscillations (i.e., 4, 10, 20 and 40 Hz) to stimuli with different envelope rise times. Our results revealed reduced neural synchronization in the alpha, beta and low-gamma frequency ranges in dyslexia. Moreover, atypical neural synchronization was modulated by rise time for alpha and beta oscillations, showing that deficits found at 10 and 20 Hz were only evident when the envelope's rise time was significantly shortened. This impaired tracking of rise time cues may very well lead to the speech and phonological processing difficulties observed in dyslexia.

Weighting of Amplitude and Formant Rise Time Cues by School-Aged Children: A Mismatch Negativity Study.

An important skill in the development of speech perception is to apply optimal weights to acoustic cues so that phonemic information is recovered from speech with minimum effort. Here, we investigated the development of acoustic cue weighting of amplitude rise time (ART) and formant rise time (FRT) cues in children as measured by mismatch negativity (MMN). Twelve adults and 36 children aged 6-12 years listened to a /ba/-/wa/ contrast in an oddball paradigm in which the standard stimulus had the ART and FRT cues of /ba/. In different blocks, the deviant stimulus had either the ART or FRT cues of /wa/. The results revealed that children younger than 10 years were sensitive to both ART and FRT cues whereas 10- to 12-year-old children and adults were sensitive only to FRT cues. Moreover, children younger than 10 years generated a positive mismatch response, whereas older children and adults generated MMN. These results suggest that preattentive adultlike weighting of ART and FRT cues is attained only by 10 years of age and accompanies the change from mismatch response to the more mature MMN response. https://doi.org/10.23641/asha.6207608.

Study of secondary muons detected within the tunnels of the Cholula pyramid

The pyramid of Cholula was built at the beginning of 100 B.C. and during of period of 500 years it was finished, had several new constructions, based on the previous constructions. The primarily material of construction is the adobe. Early in 1931 archaeological excavations began with the intention of exploring the interior of the pyramid, excavations were stopped in 1971, and to date no further excavations have been carried out. This work shows the first measurements of muons, particles that are very penetrating, these are generated by primary cosmic rays that was incoming in the atmosphere and these generates a rain of secondary particles, among them the muons. To measure this kind of particles was implemented a detector system, it is formed by a scintillator plastic coupled to a tube photomultiplier; the signals were acquired by mean of an oscilloscope. The detector was collocated near of the center of the pyramid; the location belongs to the maxima concentration in mass over the detector. Graphs of the charge distribution, maximum amplitude and characteristic rise times of the generated pulses in a plastic scintillator are shown, this is scintillator was synthesized in the materials laboratory of the FCFM-BUAP. In addition the optical characterization of the same was realized.

Spatiotemporally resolved imaging of streamer discharges in air generated in a wire-cylinder reactor with (sub)nanosecond voltage pulses

We use (sub)nanosecond high-voltage pulses to generate streamers in atmospheric-pressure air in a wire-cylinder reactor. We study the effect of reactor length, pulse duration, pulse amplitude, pulse polarity, and pulse rise time on the streamer development, specifically on the streamer distribution in the reactor to relate it to plasma-processing results. We use ICCD imaging with a fully automated setup that can image the streamers in the entire corona-plasma reactor. From the images, we calculate streamer lengths and velocities. We also develop a circuit simulation model of the reactor to support the analysis of the streamer development. The results show how the propagation of the high-voltage pulse through the reactor determines the streamer development. As the pulse travels through the reactor, it generates streamers and attenuates and disperses. At the end of the reactor, it reflects and adds to itself. The local voltage on the wire together with the voltage rise time determine the streamer velocities, and the pulse duration the consequent maximal streamer length.

Using a probabilistic model to estimate the reliability of locating acoustic emission sources

A probabilistic model for estimating the error in determining the coordinates of acoustic emission (AE) sources based on experimental data is considered. A spherical indentor was pressed in a test object to obtain a large number of AE signals. Processing of signal parameters has made it possible to reveal the dependence of the likelihood of determining the coordinate with a prescribed accuracy on the maximum amplitude and AE-signal rise time. The possibility for choosing the method of detection of the AE-signal time of arrival at receivers depending on the signal parameters has also been examined.