Amplitude Of Tone Research Articles

Sliding-band dynamic range compression for use in hearing aids

Sensorineural hearing loss is associated with elevated hearing thresholds, reduced dynamic range, and loudness recruitment. Signal processing with dynamic range compression is used in hearing aids for presenting all the sounds comfortably within the limited dynamic range of the listener. A dynamic range compression technique, named as ‘sliding-band compression’, is proposed to overcome the shortcomings of the commonly used single-band and multiband compression techniques. The gain at each frequency index is calculated as a function of the short-time power in an auditory critical band centered at it. The technique avoids the attenuation of high-frequency components due to the presence of strong low-frequency components, which may occur in single-band compression. Further, it avoids distortions in the shape of spectral resonances and discontinuities during the resonance transitions, which may occur in multiband compression. The proposed technique was implemented for offline processing and compared with single-band compression and multiband compression using objective measures and different test inputs. For two-tone inputs, the single-band compression showed attenuation of the high-frequency tone with an increase in the level of the low-frequency tone. For swept-frequency single-tone input, the multiband compression showed errors in the tone amplitude of 1.5–2.5 dB for compression ratio of 2–10. Sliding-band compression did not show either type of error. The technique has been also implemented using a fixed-point processor for real-time processing with audio latency acceptable for face-to-face communication.

Backaction-evading measurement of entanglement in optomechanics

We propose here a fully backaction-evading scheme for the measurement of the entanglement between two nanomechanical resonators. The system, which consists of two mechanical oscillators, coupled to a single mode of an electromagnetic resonant cavity through a radiation-pressure interaction term, is driven by two pump tones and four detection tones. As previously discussed in the literature, the former induce entanglement between the two mechanical oscillators, while we show here that a specific choice of phase and amplitude of the detection tones allows for direct pairwise reconstruction of the collective quadrature fluctuations of the mechanical oscillators belonging to quantum-mechanics-free subspaces, thereby providing direct evidence of the entanglement properties of the two mechanical resonators.

Mathematical model of the formation and development of wave-shaped rail wear when an electric locomotive operates in the traction mode in tangent sections of the track

The problem of wave-shaped rail wear is highly relevant for rail transport. The paper presents a mathematical model of the formation and development of wave-shaped rail wear. The task of estimating vertical wear of the rail head under the axles of electric locomotives passing in the traction mode is considered. A technique has been developed that allows building chain of calculations that determine the formation and development of a wave-shaped rail head wear. A specific calculation example is given, illustrating the process of propagation of a wave-shaped wear from the source of its formation in the direction of train motion. An example of the calculation allows drawing the following conclusions:1. Wave-shaped wear primarily occurs when the shock interaction of the wheel of an electric locomotive moving in the traction mode and a rail thread having imperfections of the rolling surface. Such imperfections, among others, may be a joint with a significant gap or a “step down” in the direction of the locomotive, as well as a welded joint with defect 46.3-4.2. Wavelength of the wave-shaped rail wear, its configuration and amplitude of the fundamental tone are determined mainly by joint oscillations of the wheel-motor unit of the locomotive and the track infrastructure in the field of high-frequency oscillations (120 – 180 Hz).3. Multivariate calculations showed that in steady state, the distribution speed of wave-shaped rail wear in the direction of train motion (as a function of the number of axles of electric locomotives passed in traction mode) is directly proportional to the vertical load at the wheel and rail contact in the slip zone 0≤Q≤F/(2nψk), is inversely proportional to wear resistance C and significantly depends on the parameters of the undercarriage of the electric train and the track superstructure.

Effect of sound pressure level on contralateral inhibition underlying duration-tuned neurons in the mammalian inferior colliculus.

Duration tuning in the mammalian inferior colliculus (IC) is created by the interaction of excitatory and inhibitory synaptic inputs. We used extracellular recordings and paired tone stimulation to measure the strength and time course of the contralateral inhibition underlying duration-tuned neurons (DTNs) in the IC of the awake bat. The onset time of a short, best duration (BD), excitatory probe tone set to +10 dB (re threshold) was varied relative to the onset of a longer-duration, nonexcitatory (NE) suppressor tone whose sound pressure level (SPL) was varied. Spikes evoked by the roving BD tone were suppressed when the stationary NE tone amplitude was at or above the BD tone threshold. When the NE tone was increased from 0 to +10 dB, the inhibitory latency became shorter than the excitatory first-spike latency and the duration of inhibition increased, but no further changes occurred at +20 dB (re BD tone threshold). We used the effective duration of inhibition as a function of the NE tone amplitude to obtain suppression-level functions that were used to estimate the inhibitory half-maximum SPL (ISPL50). We also measured rate-level functions of DTNs with single BD tones varied in SPL and modeled the excitatory half-maximum SPL (ESPL50). There was a correlation between the ESPL50 and ISPL50, and the dynamic range of excitation and inhibition were similar. We conclude that the strength of inhibition changes in proportion to excitation as a function of SPL, and this feature likely contributes to the amplitude tolerance of the responses of DTNs. NEW & NOTEWORTHY Duration-tuned neurons arise from excitatory and inhibitory synaptic inputs offset in time. We measured the strength and time course of inhibition to changes in sound level. The onset of inhibition shortened while its duration lengthened as the stimulus level increased from 0 to +10 dB re threshold; however, no further changes were observed at +20 dB. Excitatory rate-level and inhibitory suppression-level response functions were strongly correlated, suggesting a mechanism for level tolerance in duration tuning.

Voice improvement in patients with recurrent respiratory papillomatosis after combined treatment with cidofovir and CO2 laser surgery

Mechanical debulking of laryngeal papillomas is associated with voice disorders due to impairment of the vocal fold’s mucosa. Intraepithelial injection of cidofovir reduces damage to the laryngeal structures and thus improves vocal parameters. The aim of our study was to compare vocal quality before and after cidofovir and CO2 laser treatment by means of objective phoniatric parameters and to obtain evidence concerning voice outcomes. The vocal parameters of 42 patients with RRP were assessed before and after intralesional cidofovir and CO2 laser debulking treatment (Lumenis AcuPulse 40 CO2 laser, wavelength 10.6 μm; Lumenis Ltd., Yokneam, Israel). The laser was used in SuperPulse™ mode with power tailored on the target structures (average 7 W). The depth of tissue penetration was 1 mm with a single burst of energy lasting 0.3 ms. Most of the patients had previously undergone traditional surgery (1–105 procedures); in 7/42, the video stroboscopic examination revealed extensive scar tissue covering the mucosa of the vocal folds, limiting the mucosal wave. The significance level for all calculations was p < 0.05. Statistical analysis was performed using Statistica 10 by StatSoft Polska. The methodology included subjective voice evaluation (GRBAS), videostroboscopy, analysis of the acoustic laryngeal tone (MDVP), spectrographic analysis, and voice handicap index (VHI). The GRBAS scale during spontaneous conversation revealed better phonation results after cidofovir treatment in all 42 patients. Scars were not observed in the presented group. In the MDVP laryngeal tone analysis before surgery parameters defining the amplitude and frequency of laryngeal tone were significantly elevated compared to the state after surgery. After treatment, both jitter and shimmer were reduced in all subjects. Even more pronounced changes were observed in the spectrographic analysis. In all analyzed patients, there was a significant reduction in VHI scores showing improvement in voice self-assessment. A satisfactory improvement in voice quality was observed in all RRP patients treated with cidofovir and CO2 laser.

Deer browsing alters sound propagation in temperate deciduous forests.

The efficacy of animal signals is strongly influenced by the structure of the habitat in which they are propagating. In recent years, the habitat structure of temperate forests has been increasingly subject to modifications from foraging by white-tailed deer (Odocoileus virginianus). Increasing deer numbers and the accompanying browsing have been shown to alter vegetation structure and thus the foraging, roosting, and breeding habitats of many species. However, despite a large body of literature on the effects of vegetation structure on sound propagation, we do not yet know what impact deer browsing may have on acoustic communication. Here we used playback experiments to determine whether sound fidelity and amplitude of white noise, pure tones, and trills differed between deer-browsed and deer-excluded plots. We found that sound fidelity, but not amplitude, differed between habitats, with deer-browsed habitats having greater sound fidelity than deer-excluded habitats. Difference in sound propagation characteristics between the two habitats could alter the efficacy of acoustic communication through plasticity, cultural evolution or local adaptation, in turn influencing vocally-mediated behaviors (e.g. agonistic, parent-offspring, mate selection). Reduced signal degradation suggests vocalizations may retain more information, improving the transfer of information to both intended and unintended receivers. Overall, our results suggest that deer browsing impacts sound propagation in temperate deciduous forest, although much work remains to be done on the potential impacts on communication.

Restoring voice function after open diagonal resection of the larynx

The study objectiveis to perform the acoustic analysis of voice in patients after open diagonal resection of the larynx.Materials and methods. A total of 112 patients underwent diagonal resection of the larynx; of them 73 hadfrontolateral resection and 39 had expanded frontolateral resection. Primary laryngeal cancer was diagnosed in 107 patients; five patients had relapses after radiation therapy. Fifty-six participants underwent acoustic analysis of voice before surgery, 52 participants underwent it 1 month postoperatively, and 112 participants had it after completing their rehabilitation (6 months to 10 years postoperatively). To determine normal acoustic characteristics of voice, we examined 80 men with normal voice. We measured voice fundamental frequency (FF), maximum and minimum FF, FF variability, jitter, shimmer, voice intensity, amplitude of fundamental tone’s harmonics and their difference. Speech rehabilitation included breathing exercises according to E. Ya. Zolotareva and speech training according to S.L. Taptapova.Results.Patients with laryngeal cancer demonstrated significant changes in the acoustic characteristics of their voice (p &lt;0.05) compared to healthy individuals, including increased mean FF (f0) (up to 143 ± 45 Hz vs 118 ± 18 Hz in controls), decreased voice intensity (from 60 ± 8 to 43 ± 8dB), and almost 2-fold decrease in the amplitude of fundamental tone’s harmonics (ω0, 2 ω0, 3 ω0). We also found an increased dispersion and variability of acoustic characteristics assessed compared to healthy individuals. The analysis of long-term treatment outcomes demonstrated more significant improvement of voice acoustic characteristics in patients who underwent speech rehabilitation compared to those who had no rehabilitation.Conclusion.Open resection of the larynx with endoscopic removal of granulations and ligatures and laser restoration of the laryngeal lumen by dissecting the scars complemented by speech rehabilitation allow restoring respiratory function in 91.1 % of patients and restoring voice in 91.8 % of patients (to achieve acoustic characteristics close to normal).

Cardiological «patterns» in term newborn with no symptoms

Clinical examination is essential for detection of cardiac pathology in term newborns. Sensitivity of cardiac noise estimation for diagnostics of congenital malformations is up to 88%. Detection of murmurs is quite subjective and depends on the skill and experience of the doctor. Usage of an electronic stethoscope with combination of digital recording of cardiac sounds and computer analysis significantly expands the possibilities of auscultation in the diagnostics of structural heart anomalies diagnostics.Purpose.Study of the structure of echocardiographic symptoms in clinically healthy newborns in comparison with the electronic auscultation analysis data.Materials and methods. A total of 195 healthy term newborns were examined, in which no structural features in the heart and large vessels were prenatally found. No pathological changes were identified with the traditional auscultation after birth. During the first 5 days of life, doppler echocardiography, differential pulse-oximetry, electronic auscultation were performed. The analysis of the received phonocardiograms was carried out with the developed computer program "Hearttone-D" with the analysis of 17 parameters of tone I and II and 16 parameters of intervals between tones at five standard listening points.Results. During the Doppler echocardiography study, all children had a functional oval window measuring from 2.0 to 4.5 mm. In 5 children (2.6%) the small size defects in the interventricular membrane were found. Signs of the PDA during the observation period were found in 54 (27.6%) newborns. Pulse-oximetry results in newborns were within 96-99% range.For the computer analysis, 27 phonocardiographs of newborns with PDA and 28 neonatal phonocadiograms of newborns with closed ductus arteriosus were selected. The inclusion criterion was the size of a functioning oval window 2.5-3.0 mm, the absence of any structural anomalies of the heart, the quality of recording of the phonocardiograph (no exterior sounds). The largest statistically significant difference between the parameters was observed at the II auscultation point (the maximum amplitude of tone I, the average value of tone II, the average amplitude module in the first interval, the mean amplitude module in the last quarter of the second interval, the width of the second interval).Conclusions. Тhe presence of clinically undetectable at the time of the PDA is detected by electronic auscultation end the highest statistical significance is characterized by parameters registered in the II point of auscultation.

PENGARUH AMPLITUDE SONIC BLOOM SINGLE TONE TERHADAP PERKECAMBAHAN BENIH TOMAT CHERRY (Lycopersicum cerasiforme Mill.) SEBAGAI DESAIN SUMBER BELAJAR BIOLOGI

: Sound exposure to seed germination is an attempt to increase germination, growth in stem length and sprout width. This study aims to determine the effect of amplitude (Sound Level) on the germination of cherry tomato seeds, to know the best amplitude Single Tone for the efficiency of germination of cherry tomato seeds and to compile the results of research as a source of learning on growth and growth material in plants in the form of Student WorkSheets. The research design using Completely Randomized Design, with 5 treatments and 4 replications. The treatment is Single Tone amplitude / volume (decibel / dB) variation consisting of P0 (without sound), P1 (65 dB), P2 (75 dB), P3 (85 dB) and P4 (95 dB). The results showed that the amplitude Single Tone significantly affected the growth of stem length and leaf width (P> 0,05). The best treatment is P3 with amplitude 85 dB which produces average germination rate, the growth of stem length and leaf width of 99%, 5.84 cm and 0.29 cm, respectively, whereas the lowest treatment on without sound (P0) 91% for germination, and 0.23 cm for leaf width. As well as on P4 (95 dB) of 4.90 cm for the length of cherry tomato sprout stems. Research results can be developed as learning resources in the form of Student WorkSheets. Keywords: Amplitude (dB) Cherry Tomato Seed, Germination, Single Tone

Perceptual Encoding in Auditory Brainstem Responses: Effects of Stimulus Frequency.

A central question about auditory perception concerns how acoustic information is represented at different stages of processing. The auditory brainstem response (ABR) provides a potentially useful index of the earliest stages of this process. However, it is unclear how basic acoustic characteristics (e.g., differences in tones spanning a wide range of frequencies) are indexed by ABR components. This study addresses this by investigating how ABR amplitude and latency track stimulus frequency for tones ranging from 250 to 8000 Hz. In a repeated-measures experimental design, listeners were presented with brief tones (250, 500, 1000, 2000, 4000, and 8000 Hz) in random order while electroencephalography was recorded. ABR latencies and amplitudes for Wave V (6-9 ms) and in the time window following the Wave V peak (labeled as Wave VI; 9-12 ms) were measured. Wave V latency decreased with increasing frequency, replicating previous work. In addition, Waves V and VI amplitudes tracked differences in tone frequency, with a nonlinear response from 250 to 8000 Hz and a clear log-linear response to tones from 500 to 8000 Hz. Results demonstrate that the ABR provides a useful measure of early perceptual encoding for stimuli varying in frequency and that the tonotopic organization of the auditory system is preserved at this stage of processing for stimuli from 500 to 8000 Hz. Such a measure may serve as a useful clinical tool for evaluating a listener's ability to encode specific frequencies in sounds. https://doi.org/10.23641/asha.6987422.

Efficient Behavioral Simulation of Charge-Pump Phase-Locked Loops

The simulation of the full netlist of a phase locked loop (PLL) is resource demanding due to the prohibitive time needed to derive output noise, spurs, and transient performance from detailed transistor-level simulations. To overcome this limitation, behavioral models are needed but they must be accurate and time-efficient. This paper introduces a new behavioral macro-model of the charge-pump PLL, addressing both spectral analysis and lock-in transient computation. To meet both accuracy and simulation efficiency, the model accounts for the time-variant transfer of noise and disturbances, and a novel procedure is introduced to extract the model parameters via transistor-level periodic steady-state simulations. To describe the nonlinear dynamics, the model also includes the voltage-controlled oscillator and charge-pump nonlinear characteristic computed via transistor-level simulations. The proposed macro-model has been tested on a 2.765-GHz PLL, and the results are compared against the noise transient simulation of the PLL full netlist. Phase noise and amplitude of spurious tones, both inherently generated and induced by external disturbances, are predicted within ±2 dB. Lock-in transients are also described with an accuracy within a few percent. On the other hand, the simulation time reduction is two/three orders of magnitude for both spectral analyses and transient simulations, depending on the PLL parameters.

Optimal Operation of a Josephson Parametric Amplifier for Vacuum Squeezing

A Josephson parametric amplifier (JPA) can create squeezed states of microwave light, lowering the noise associated with certain quantum measurements. We experimentally study how the JPA's pump influences the phase-sensitive amplification and deamplification of a coherent tone's amplitude when that amplitude is commensurate with vacuum fluctuations. We predict and demonstrate that by operating the JPA with a pump power greater than the value that maximizes gain, the amplifier distortion is reduced and consequently squeezing is improved. Optimizing the JPA's operation in this fashion, we directly observe $3.87 \pm 0.03$ dB of vacuum squeezing.

F159. NEUROMAGNETIC 40 HZ AUDITORY STEADY STATE RESPONSES AND AUDITORY CORTICAL GABA AND GLX IN CLINICAL HIGH RISK AND FIRST EPISODE OF PSYCHOSIS INDIVIDUALS

BackgroundRobust impairments in the power and phase of 40 Hz auditory steady state responses (ASSR) have been reported in chronic schizophrenia patients. This could reflect changes in the balance between inhibitory GABAergic and excitatory glutamatergic neurotransmission in auditory cortex. However, the direct link between the ASSR and alterations in these neurotransmitter systems has not been systematically explored. Furthermore, it remains unclear whether 40 Hz ASSR impairments are present in early and at-risk stages of psychosis. The current study aims to explore the 40 Hz ASSR in first-episode of psychosis patients and individuals at clinical high risk (CHR) of psychosis, and the possible relationship of deficits in gamma-band entrainment to a dysfunctional excitation inhibition balance, as reflected by alterations in cortical GABA and glutamate.MethodsData from 80 CHR, 11 FEP and 40 age-matched healthy control participants were collected as part of the MRC-funded Youth Mental Health Risk and Resilience study. MEG data were recorded on a 4D Neuroimaging Magnes 3600 Whole Head 248 Channel system, while participants were passively presented with a series of 1000 Hz carrier tones amplitude modulated at 40 Hz. Data were analysed at sensor and source-level in the frequency-domain for spectral power and intertrial phase-coherence (ITPC). For source-reconstruction, an eLoreta source-analysis algorithms was employed. Auditory regions of interest (ROIs) were defined using 98 nodes defined from the AAL-atlas. Levels of right auditory GABA and Glx (glutamate + glutamine) were measured using 1H-MRS at 3T and 2*2*2 cm voxels and were estimated relative to water. GABA levels were further corrected for grey and white matter and cerebrospinal fluid levels within the voxel. Finally, 40 Hz ASSR power in right auditory cortex was explored in relation to neurotransmitter levels in the same region.ResultsAcross groups, the ASSR stimulus activated temporal regions, including bilateral heschl’s gyrus and superior temporal cortex. A significant effect of hemisphere was found, reflecting higher 40 Hz ASSR power in the right hemisphere across groups. CHR and FEP participants showed attenuated 40 Hz ASSR power and ITPC compared to healthy control participants in right temporal regions, but an increase in spectral power in the left hemisphere. A moderate positive correlation was found between right auditory GABA and 40 Hz ASSR power in the right superior temporal gyrus in CHR, but not in controls.DiscussionThese results provide a link between MRS measures of GABA and 40 Hz ASSR power impairments in CHR individuals. Furthermore, these preliminary findings indicate that slight alterations in the 40 Hz ASSR are present in FEP patients and may arise already in the CHR stage, prior to the onset of psychosis.

Analysis of pressure fluctuation in transonic cavity flows using modal decomposition

Turbulent flows at a free stream Mach number of 1.19 over an open cavity with L/D ratio of 5.0 are numerically investigated using improved delayed detached-eddy simulation based on two-equation shear stress transport model. Modal decompositions including proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) are applied to analyze the pressure fluctuations. The extracted first six POD modes possess more than 75% of the total energy and contain multiple frequencies. Their spatial structures exhibit well regular and periodic behaviors along the cavity lip line. The DMD algorithm identifies the flow structures associated with single frequencies. Major distribution areas of high intensity pressure fluctuations move upstream as the mode frequency increases, and the structures with high frequencies are prone to break down near the trailing edge. The alternating pressure patterns convection process is clearly presented, and the propagation of acoustic waves validates that the acoustic waves share the same sound source but are radiated following two different paths, consistent with the feedback mechanism. In addition, the effects of free stream Reynolds number on sound pressure spectrum levels are investigated at a fixed pressure and temperature. Results show that free stream Reynolds number has no effect on the non-dimensional frequencies of the dominant modes, while the main recirculation area shrinks as Reynolds number increases. Furthermore, variations of sound pressure levels as a function of Reynolds numbers exhibit significant discrepancies for a fixed free stream pressure or temperature, indicating that the Reynolds number is not critical to the feedback tone amplitude. The enhancement of sound pressure levels mainly attributes to the increment of free flow pressure or the impingement of enlarged fluid velocity due to higher free stream temperature.

Effects of age and noise exposure on the representation of amplitude modulation

Age and lifetime noise exposure were used as predictors for electrophysiological and psychophysical measures of amplitude modulation processing. Frequency-following responses (FFRs) were recorded from 61 listeners (20 young, 23 middle-aged, 18 elderly) to 0.6- and 2-kHz, 75-dB SPL, carrier tones amplitude modulated at 100 Hz. A pink noise highpass-filtered at 3 kHz was included to mask basal cochlear contributions to the FFR. Sinusoidal amplitude modulation detection (AMD) thresholds were measured for the same listeners for a 2-kHz carrier (40 and 80 dB SPL) and for three modulation frequencies (25, 50, and 100 Hz). The carrier was presented in notched pink noise to limit off-frequency listening. Lifetime noise exposure was estimated using a structured interview. A regression model was used to determine the independent contributions of age and noise exposure, while controlling for audiometric threshold. FFR amplitude for the 0.6 kHz carrier showed a marked age-related decline. Age was also associated with a significant increase in AMD thresholds. Lifetime noise exposure was not significantly associated with either FFR amplitude or AMD threshold. The results suggest that age is a stronger predictor of modulation processing deficits than lifetime noise exposure.

Numerical analysis of the impact of variable porosity on trailing-edge noise

The impact of porous material with variable properties on trailing-edge noise is analyzed by a high resolution large-eddy simulation/computational aeroacoustics (LES/CAA) approach. Two trailing edge shapes, i.e., a sharp edge and a rounded edge, with solid and porous surfaces are considered. The numerical solution of the rounded corner trailing edge is validated by experimental data of surface pressure and acoustic spectra. The viscous dissipation in the porous structures directly influences the acoustic attenuation by reducing the correlation length of the turbulent eddies and the flow acceleration near the trailing edge. At zero angle-of-attack the porous surface is extremely effective to reduce the tone and the broadband noise. An optimized porosity distribution further decreases the tone amplitude. At increasing angle-of-attack the enhanced flow momentum in the direction of streamline curvature enlarges the turbulent length scale and the maximum turbulence intensity. The acoustic field of the porous trailing edges is dominated by a large turbulent scale enhanced by the streamline curvature variation. The low-frequency acoustics increases and its wave propagation is more pronounced in the downstream direction. Nevertheless, the porous trailing edge is an effective means to lower the noise by 4 dB reduction in the upstream direction.

Does Sleep Bruxism Contribute to Headache-Related Disability After Mild Traumatic Brain Injury? A Case-Control Study.

To explore whether traumatic brain injury (TBI) patients have a higher prevalence of sleep bruxism (SB) and a higher level of orofacial muscle activity than healthy controls and whether orofacial muscle activity in the context of mild TBI (mTBI) increases the risk for headache disability. Sleep laboratory recordings of 24 mTBI patients (15 males, 9 females; mean age ± standard deviation [SD]: 38 ± 11 years) and 20 healthy controls (8 males, 12 females; 31 ± 9 years) were analyzed. The primary variables included degree of headache disability, rhythmic masticatory muscle activity (RMMA) index (as a biomarker of SB), and masseter and mentalis muscle activity during quiet sleep periods. A significantly higher prevalence of moderate to severe headache disability was observed in mTBI patients than in controls (50% vs 5%; P = .001). Although 50% and 25% of mTBI patients had a respective RMMA index of ≥ 2 episodes/hour and ≥ 4 episodes/hour, they did not present more evidence of SB than controls. No between-group differences were found in the amplitude of RMMA or muscle tone. Logistic regression analyses suggested that while mTBI is a strong predictor of moderate to severe headache disability, RMMA frequency is a modest but significant mediator of moderate to severe headache disability in both groups (odds ratios = 21 and 2, respectively). Clinicians caring for mTBI patients with poorly controlled headaches should screen for SB, as it may contribute to their condition.

Experimental study of supersonic flow over cavity with aft wall offset and cavity floor injection

Experimental studies were conducted at Mach 1.71 supersonic flow over open cavity to find the best configuration of combined passive (aft wall offset) and active methods (cavity floor injection) to optimize the noise suppression. Cavity of length to depth ratio 3 with 0%, 5% and 10% aft wall offset were analyzed with the combined effect of 2 bar, 4 bar and 6 bar injection pressures, injected from locations of 25%, 50% and 75% of cavity length from the front wall. Experimental methodology includes instantaneous schlieren visualization and unsteady pressure measurements. In all the schlieren images, the presence of shear layer and various cavity flow features are clearly visible. Suppression in tonal amplitude for increase in offset and injection pressure is observed for various injection locations. Injection location at 75% cavity length from front wall was found to provide the maximum suppression. Spectrogram plots clearly indicate the redistribution of energy among tones and broadband noises. Increase in the number of tones is observed for higher injection pressure and aft wall offset combination. Nature of acoustic wave is confirmed from correlation and coherence plot. Over All Sound Pressure Level (OASPL) and normalized mean pressure plot are used to perform comparative study for various configurations.

High quality factor manganese-doped aluminum lumped-element kinetic inductance detectors sensitive to frequencies below 100 GHz

Aluminum lumped-element kinetic inductance detectors (LEKIDs) sensitive to millimeter-wave photons have been shown to exhibit high quality factors, making them highly sensitive and multiplexable. The superconducting gap of aluminum limits aluminum LEKIDs to photon frequencies above 100 GHz. Manganese-doped aluminum (Al-Mn) has a tunable critical temperature and could therefore be an attractive material for LEKIDs sensitive to frequencies below 100 GHz if the internal quality factor remains sufficiently high when manganese is added to the film. To investigate, we measured some of the key properties of Al-Mn LEKIDs. A prototype eight-element LEKID array was fabricated using a 40 nm thick film of Al-Mn deposited on a 500 μm thick high-resistivity, float-zone silicon substrate. The manganese content was 900 ppm, the measured Tc = 694 ± 1mK, and the resonance frequencies were near 150 MHz. Using measurements of the forward scattering parameter S21 at various bath temperatures between 65 and 250 mK, we determined that the Al-Mn LEKIDs we fabricated have internal quality factors greater than 2 × 105, which is high enough for millimeter-wave astrophysical observations. In the dark conditions under which these devices were measured, the fractional frequency noise spectrum shows a shallow slope that depends on bath temperature and probe tone amplitude, which could be two-level system noise. The anticipated white photon noise should dominate this level of low-frequency noise when the detectors are illuminated with millimeter-waves in future measurements. The LEKIDs responded to light pulses from a 1550 nm light-emitting diode, and we used these light pulses to determine that the quasiparticle lifetime is 60 μs.

Measuring the dispersive frequency shift of a rectangular microwave cavity induced by an ensemble of Rydberg atoms

In recent years the interest in studying interactions of Rydberg atoms or ensembles thereof with optical and microwave frequency fields has steadily increased, both in the context of basic research and for potential applications in quantum information processing. We present measurements of the dispersive interaction between an ensemble of helium atoms in the 37s Rydberg state and a single resonator mode by extracting the amplitude and phase change of a weak microwave probe tone transmitted through the cavity. The results are in quantitative agreement with predictions made on the basis of the dispersive Tavis-Cummings Hamiltonian. We study this system with the goal of realizing a hybrid between superconducting circuits and Rydberg atoms. We measure maximal collective coupling strengths of 1 MHz, corresponding to 3*10^3 Rydberg atoms coupled to the cavity. As expected, the dispersive shift is found to be inversely proportional to the atom-cavity detuning and proportional to the number of Rydberg atoms. This possibility of measuring the number of Rydberg atoms in a nondestructive manner is relevant for quantitatively evaluating scattering cross sections in experiments with Rydberg atoms.