bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcutaneous electrical cranial‐auricular acupoint stimulation versus escitalopram for mild‐to‐moderate depression: An assessor‐blinded, randomized, non‐inferiority trial
Authors: Zhang Zhang‐Jin , Zhang Shui‐Yan , Yang Xin‐Jing , Qin Zong‐Shi , Xu Feng‐Quan , Jin Gui‐Xing , Hou Xiao‐Bing , Liu Yong , Cai Ji‐Fu , Xiao Hai‐Bing , Wong Yat Kwan , Zheng Yu , Shi Lei , Zhang Jin‐Niu , Zhao Yuan‐Yuan , Xiao Xue , Zhang Liu‐Lu , Jiao Yue , Wang Yu , He Jia‐Kai , Chen Guo‐Bing , Rong Pei‐Jing
Published: November 2022

Aim

Transcutaneous electrical cranial‐auricular acupoint stimulation (TECAS) is a novel non‐invasive therapy that stimulates acupoints innervated by the trigeminal and auricular vagus nerves. An assessor‐blinded, randomized, non‐inferiority trial was designed to compare the efficacy of TECAS and escitalopram in mild‐to‐moderate major depressive disorder.

Methods

468 participants received two TECAS sessions per day at home (n = 233) or approximately 10–13 mg/day escitalopram (n = 235) for 8 weeks plus 4‐week follow‐up. The primary outcome was clinical response, defined as a baseline‐to‐endpoint ≥50% reduction in Montgomery‐Åsberg Depression Rating Scale (MADRS) score. Secondary outcomes included remission rate, changes in the severity of depression, anxiety, sleep and life quality.

Results

The response rate was 66.4% on TECAS and 63.2% on escitalopram with a 3.2% difference (95% confidence interval [CI], −5.9% to 12.9%) in intention‐to‐treat analysis, and 68.5% versus 66.2% with a 2.3% difference (95% CI, −6.9% to 11.4%) in per‐protocol analysis. The lower limit of 95% CI of the differences fell within the prespecified non‐inferiority margin of −10% (P ≤ 0.004 for non‐inferiority). Most secondary outcomes did not differ between the two groups. TECAS‐treated participants who experienced psychological trauma displayed a markedly greater response than those without traumatic experience (81.3% vs 62.1%, P = 0.013). TECAS caused much fewer adverse events than escitalopram.

Conclusions

TECAS was comparable to escitalopram in improving depression and related symptoms, with high acceptability, better safety profile, and particular efficacy in reducing trauma‐associated depression. It could serve an effective portable therapy for mild‐to‐moderate depression.
Monetary, fiscal, and structural drivers of inflation in Ethiopia: new empirical evidence from time series analysis
Authors: Ndikumana Léonce , Nkurunziza Janvier D. , Sánchez Martín Miguel Eduardo , Mulugeta Samuel , Getachew Kelbore Zerihun
Published: November 2022

This study empirically investigates the drivers of inflation in Ethiopia using monthly data over the period July 1998 to September 2020. It explores short‐run and long‐run effects of domestic and external determinants of inflation—including demand‐side, supply‐side, and structural factors—using the cointegration and vector error‐correction methodology. Four measures of inflation are considered: cereals, food, nonfood, and all‐items Consummer Price Index (CPI) inflation. A key contribution to the existing literature is the investigation of the role of the fiscal sector in modeling inflation, a topic that has been neglected in the existing studies on inflation in Ethiopia. The empirical results show that disequilibria in the monetary sector, grains sector, and food markets have long‐run effects on inflation. In the short run, inflation is driven by structural factors (notably, cereal output gaps and imported inflation) as well as demand‐side factors (notably, money growth and public sector borrowing). The results hold when analysis is limited to the high growth period from 2005 onward, following the end of the International Monetary Fund (IMF) program in the country. The evidence provides valuable insights in the context of ongoing macroeconomic policy reforms in Ethiopia.
Understanding the essence of care in nurses' lived stories: A phenomenological study
Authors: Kol Emine , Boz İlkay , Bolattürk Gamze , İlaslan Emine
Published: November 2022

Background

Caring contains understanding and connecting with the individual and the process of providing the healing effect. Nurses' awareness of the science of care can be improved by analyzing and sharing their care experiences, including their healing power, with members of the profession.

Aim

The aim of this study was to understand the meaning of care from nurses' experiences and the real‐life stories told by nurses.

Method

A descriptive phenomenological design was used. A total of 124 stories told by 23 nurses participating in the training of Human Caring Theory constituted the sample of the study. The content analysis of the stories was carried out in four stages with Giorgi's phenomenological method analysis.

Results

Three themes and six subthemes were derived from the 124 stories. Three main themes: (1) care holds mysteries, (2) care as praxis and (3) obstacles to caring relationship. The first main theme consisted of three subthemes; “Hearing the call for help”, “Metaphysical presence” and “Discovery of the healing effect”. The second main theme consisted of three subthemes; “Criticism of the objective approach”, “Unforgettable experiences of carecaring experiences” and “Awareness of expertise”.

Conclusion

The use of stories in the training of Human Caring Theory that centers care, besides facilitating learning, has created awareness among nurses about the ‘Concept of Care’ and has been an important step towards developing awareness of care among nurses.
Energy Harvesting Performance of Thick Oscillating Airfoils Using a Discrete Vortex Model
Authors: Fard Kiana Kamrani , Ngo Vickie , Pence Deborah , Liburdy James
Published: November 2022

The energy harvesting performance of thick oscillating airfoils is predicted using an inviscid discrete vortex model (DVM). National Advisory Committee for Aeronautics (NACA) airfoils with different leading-edge geometries are modeled that undergo sinusoidal heaving and pitching with reduced frequencies, k=fc/U∞, in the range 0.06−0.14, where f is the heaving frequency of the foil, c is the chord length, and U∞ is the freestream velocity. The airfoil pitches about the midchord with heaving and pitching amplitudes of h0=0.5c and θ0=70 deg, respectively, known to be in the range of peak energy harvesting efficiencies. A vortex shedding initiation criteria is proposed based on the transient local wall stress distribution determined from computational fluid dynamics (CFD) simulations and incorporates both timing and location of leading-edge separation. The scaled shedding times are shown to be predicted over the range of reduced frequencies using a timescale based on the leading-edge shear velocity and radius of curvature. The convection velocity of the shed vortices is also modeled based on the reduced frequency to better capture the dynamics of the leading-edge vortex. An empirical trailing-edge separation correction is applied to the transient force results using the effective angle of attack modified to include the pitching component. Impulse theory is applied to the DVM to calculate the transient lift force and compares well with the CFD simulations. Results show that the power output increases with increasing airfoil thickness and is most notable at higher reduced frequencies where the power output efficiency is highest.
A Remote Moment of Inertia Lab Using the iOLab Device
Authors: Preisler Vanessa , Shume Esayas , Talbot Jean
Published: November 2022

Due to the COVID-19 pandemic, in the spring of 2020 many physics programs were forced to quickly transition all of their classes and laboratories to a completely online learning environment. The need for simple and engaging remote physics laboratories became apparent. One relatively low-cost remote lab system is Macmillan’s iOLab device. This wireless device comes with free software and a lab manual with many mechanics and electricity and magnetism experiments appropriate for lower-division physics labs. Extensive reviews of the iOLab device, including descriptions of all its sensors and capabilities as well as comparisons with other remote learning devices, can be found in recent publications. In addition, findings from these publications indicate improvements in attitudes toward physics labs and significant conceptual learning gains for students in remote lab courses that use the iOLab device. Here, we present a novel moment-of-inertia lab using the iOLab device and a few household items. In this lab, students will be able to measure the moment of inertia of the iOLab device about an axis parallel to the longer side of the iOLab device (the y-axis in Fig. 1) and through its geometrical center.
Experimental Justification of the Poggendorff Experiment
Authors: Coelho Ricardo
Published: November 2022

Atwood invented a machine in the 1780s that enabled him to observe the motion of a falling body as slowly as desired. This machine was equipped with the necessary means to measure the distance covered by the body and the time taken. With this data, it was possible, in addition to studying the falling motion, to calculate the local gravitational constant. In the mid-19th century, this machine appeared reduced to its core: two bodies hanging from a thread passing over a pulley. This device, which we call the Atwood machine, has been the subject of experimental and theoretical research. On the other hand, this is a typical textbook problem and has great pedagogical value. Poggendorff performed the first experimental research on the Atwood machine. He weighed an Atwood machine when it is prevented from moving and when in motion. He verified that the machine weighs less when in motion. This experiment has been confirmed over time. What has never been shown is how the effective weight of each body on the machine varies. This is the task of the present paper.
Towards the determination of appropriate sampling schemes within tidewater glacierized fjords
Authors: Zeh Matthew C. , Catania Ginny , Wilson Preston S. , Ballard Megan , Davis Marcy , Duncan Dan
Published: November 2022

Using an optimal duty cycle (DC) can extend the length of recording deployments without greatly reducing the information collected and is critical for measurements in dynamic, remote environments like glacierized fjords. The DC selection is often based on the recording system (battery life/memory) rather than the information in the data. We propose an improved, data-informed method to determine the optimal DC. Fifty-two hours of ambient acoustic data were collected from two underwater vertical line arrays moored near Hubbard and Turner Glaciers in Southeast Alaska in June 2021, prior to a year-long deployment. Two-second-averaged power density spectra were calculated for each of the four channels of both moorings. Spectra were clustered for each recording channel using the k-means clustering algorithm. The process was repeated for a range of DCs from 100% to 1%. Comparisons between clustered prototypes and cluster observations were made between the full and reduced duty cycle (RDC) recordings using 2, 3, 4, 5, and 6 clusters. For DCs greater than 22% (when using four clusters), the information content within the RDC recordings was not significantly enhanced. While this result is specific to this glacierized fjord, we propose this method to optimize DC selection for other passive monitoring applications.
Probing the mechanisms of acoustic droplet vaporization
Authors: Aliabouzar Mitra
Published: November 2022

Phase-shift emulsions (PSEs) undergo a phase-transition to a gaseous state when subjected to sufficient pressures delivered by an ultrasound source. This phenomenon, termed acoustic droplet vaporization (ADV), has broadened the scope of ultrasound-based applications, resulting in novel diagnostic and therapeutic techniques. Since the introduction of ADV, design and fabrication methods of PSEs have progressed substantially. Development of PSEs with different thermophysical properties (e.g., perfluorocarbon core and size) has enabled modulation of ADV dynamics for specific applications. A variety of microscopy techniques have been utilized to characterize the response of different PSEs under varying acoustic conditions at relevant timescales for diagnostic and therapeutic applications. Ultra-high-speed microscopy enabled study of ADV dynamics from the inception of the vapor nucleus at nanosecond time scales to the growth of the generated bubbles seconds post ADV. The kinetics of ADV-induced drug release have been captured at multiple timescales via high-speed fluorescence microscopy. Confocal and atomic force microscopy techniques have provided insight into ADV-induced changes to the environment surrounding a PSE/bubble. Additionally, great progress has been made in the theoretical framework to predict ADV dynamics under different acoustic conditions. This talk will review physical mechanisms underpinning ADV and highlight new emerging applications.
A comparative study of the directional characteristics of two gamelan gongs
Authors: Harwood Dallin T. , Bellows Samuel D. , Avila Joseph E. , Gee Kent L.
Published: November 2022

While previous research on the structural modes of gamelan gongs has revealed important insight into its unique acoustics, little attention has been dedicated to study the directionality of their acoustic radiation. This study compares high-angular resolution spherical directivity measurements of two Balinese gamelan gongs of different sizes. The directional characteristics are usually closely connected with measured structural modes at both low and high frequencies. However, the directivities of the large and small gong for the same structural mode shape are not always consistent, particularly at higher frequencies. Thus, changes in modal frequencies due to the scaling of the gongs do not always indicate similar acoustical radiation patterns.
The effects of night-time aviation noise exposure on sleep disturbance and annoyance
Authors: Clark Charlotte , Toomse-Smith Mari , Basner Mathias , Trow James , Marcheselli Franziska , Mandalia Dhriti , Steinbach Rebecca , Morris Joan , Gibbs George , Marcus Elena
Published: November 2022

This paper will report on the methodology for a new UK study of aviation night-noise exposure on health. Funded by the United Kingdom Department of Transport (DfT), the study is examining the effects of aviation night-noise exposure for a range of night-time periods on sleep disturbance and annoyance. The study involves a cross-sectional survey of 4000 participants living near eight UK airports to assess associations of aircraft noise exposure at night and subjective sleep disturbance and annoyance, as well as an objective sleep disturbance study of 170 participants, where physiological assessments of sleep disturbance will be linked to aircraft noise exposure at the participant’s home. The study will deliver exposure-response functions showing how time-averaged metrics such as LAeq,8h, LAeq,1h, N60 relate to subjective and objective sleep disturbance, and annoyance, which could be used to inform updates to the DfT’s Transport Analysis Guidance (TAG) and subsequently aviation night-noise policy in the UK. It will also explore if a relationship for objective sleep disturbance can be estimated for event-related metrics such as LAmax and sound exposure level. Effect modification will be examined; quantifying whether some population groups may be more vulnerable to the effects of aviation night-noise on sleep disturbance and annoyance.
On the effect of training simulation point spread function in deep-learning based super-resolution ultrasound imaging
Authors: Chen Xi , You Qi , Dong Zhijie , Lowerison Matthew R. , Song Pengfei
Published: November 2022

Deep learning (DL)-based super-resolution ultrasound microvascular imaging (SR-UMI) has gained interest in recent years owing to the success of DL in medical imaging applications. Mainstream DL techniques require an abundance of labeled training data. Since high-quality in vivo training data are challenging to obtain for medical imaging, most of the current studies have relied on simulations to generate training data of microbubbles (MBs) flowing in vasculature. This study investigates the effect of different MB point spread function (PSF) generation methods on the performance of DL models for SR-UMI. We used Gaussian shaped PSF (Gaussian-PSF), numerical simulation software (Field II-PSF), and experimentally collected PSFs (Exp-PSF) to generate DL training sets. The training sets were used to train DL models that performed both MB localization- and non-localization-based SR-UMI. The quality of the models trained with different datasets were evaluated based on their in vivo performance (mouse brain, chicken embryo), with optical imaging as ground truth for some applications. We discovered that Exp-PSF achieved the best performance overall, due to its high resemblance to real experimental data. Finally, we present a pipeline for obtaining Exp-PSF and integrating them with ultrasound MB simulation, with a publicly available Exp-PSF dataset provided via Github.
Prosody analysis as a tool for differential diagnosis of cognitive impairment
Authors: Oh Chorong , Morris Richard J. , Wang Xianhui
Published: November 2022

This study was conducted to determine whether acoustic analysis of emotional prosody can assist in differential diagnosis of cognitive impairment. Speech samples describing the Cookie Theft picture were obtained from the Dementia Talkbank and analyzed acoustically. Included in this speech dataset were 10 people with dementia of the Alzheimer’s type, 9 people with mild cognitive impairment, 5 people with vascular dementia, and 10 neurotypical controls. The principal component analysis revealed five factors with two to five acoustic measures per factor for differential diagnosis of cognitive impairment.
Spectral changes to sound exposure when preterm infants transition from the incubator to an open crib
Authors: Ananthanarayana Rohit M. , Monson Brian B.
Published: November 2022

Children born preterm are at risk for speech and language developmental delays and disorders. It has been proposed that adverse auditory exposures during stay in the neonatal intensive care unit (NICU) may contribute to this risk, as it is well-established that the preterm infant’s developing auditory system is sensitive to acoustic input during this time. While reduced speech exposure, noxious noise levels, and excessive silence in the NICU are of concern, another potential cause for concern is abrupt changes in auditory exposure during NICU stay. Our previous data indicate that NICU incubator walls have a low-pass filtering effect, attenuating external sounds at frequencies above 200 Hz. However, internal sounds generated by the incubator or other life-saving devices still produce noise exposure. Furthermore, when infants transition to an open crib from the incubator based on improved overall health, they may be at risk of increased exposure to higher frequencies. Here we present spectral analyses of auditory exposure recordings made for several preterm infants throughout NICU stay. Our analysis reveals that for frequencies above 500 Hz, sound levels are significantly higher in the open crib; below 500 Hz, levels are generally higher in the incubator. These data point to yet another potentially disruptive effect of the NICU environment caused by an abrupt change in auditory exposure.
A descriptive study on the acoustic and kinematic characteristics of internal open junctures: Implications for highly intelligible individuals with Parkinson’s disease
Authors: Kuo Christina
Published: November 2022

This study extends previous work on the acoustic characteristics of ambiguous sentences for male speakers with Parkinson’s disease (PD) [Kuo, JASA 148(4), 2583 (2020)] with additional data. Specifically, the purpose of this study is to further understand acoustic and articulatory characteristics of internal open junctures for speakers with PD. Internal open junctures consist of set strings of phonemes that are phonetically and/or semantically ambiguous when there exist two or more ways to segment the phoneme strings [Lehiste, Phonetica 5(Suppl. 1), 5–54 (1960); Fisher & Logemann, Q. J. Speech 53(4), 365–373 (1967)]. As a part of a larger study, speech acoustic output and tongue kinematic data from four male speakers of American English with PD and two neurologically healthy males were captured simultaneously using 3D electromagnetic articulography. Vocalic segments of internal open junctures were identified acoustically from ambiguous sentence productions, in which the internal open junctures were obtained in pairs, with each phoneme string contributing to two different word combinations. The second formant (F2) and tongue kinematic trajectories are compared for these pairs. It is hypothesized that for the same phoneme string, varied linguistic boundaries elicit differences in tongue trajectory patterns and F2 changes in duration and speed.
Engaging effort improves efficiency during word recognition in cochlear implant users
Authors: Colby Sarah , Huffman Marissa , McMurray Bob
Published: November 2022

Cochlear Implant (CI) users must cope with the degraded spectral input received through their device. This reduced quality leads to changes in how words are recognized: lexical access is delayed, leading to differences in competition between lexical candidates. CI users also report increased effort and fatigue during language processing, but effort is not clearly related to improved accuracy. We investigated the role that listening effort plays in the dynamics of word recognition. We related lexical competition and listening effort in 77 post-lingually deaf CI users with Visual World Paradigm and pupillometry tasks. Subjects also completed measures of peripheral auditory function (spectral ripple discrimination and temporal modulation detection). We used the difference in pupil size during the recognition of spoken and written words to isolate effort for spoken word recognition. Difference in pupil size predicted efficiency in the spoken word recognition task, over and above age and peripheral fidelity. That is, CI users who engage more effort were faster to recognize words and showed lexical competition similar to normal hearing listeners. This interacted with spectral resolution: better discrimination offsets the need to engage effort. This suggests that listening effort can be engaged to improve efficiency during word recognition.
Maintenance of phonological contrast in speech production of cochlear implant users
Authors: Sevich Victoria , Moberly Aaron C. , Tamati Terrin N.
Published: November 2022

Prior work has shown that normal-hearing (NH) talkers produce more distinct vowels in words having a lower word frequency (WF) and higher neighborhood density (ND). Phonological contrast in speech production may differ between post-lingually deafened cochlear implant (CI) users and individuals with NH due to the degraded auditory input provided by CIs. The current study sought to determine whether the same pattern of vowel production exists in CI users. CI users were recorded reading monosyllabic words that were lexically “hard” (low WF, high ND) or “easy” (high WF, low ND). For each participant, vowel dispersion was calculated as the Euclidian distance from the center of the acoustic vowel space. If degraded acoustic input affects phonological contrast in CI users, we would not expect vowel dispersion to differ between vowels in “hard” and “easy” words, contrary to talkers with NH. Preliminary results revealed a significant effect of lexical difficulty on vowel dispersion, indicating that CI users produced more distinct vowels in “hard” words than in “easy” words. These preliminary findings could suggest that degraded auditory input does not substantially affect phonological contrast in vowel production in CI users, or that long-term adaptation to CI input can restore contrast after auditory deprivation.
Improved single snapshot beamforming in a noisy environment using the cubic autoproduct
Authors: Joslyn Nicholas J. , Dowling David R.
Published: November 2022

The presence of random noise is a challenge for remote sensing tasks as success typically diminishes with decreasing signal-to-noise ratio (SNR). To improve performance in noisy environments, signal processing techniques commonly implement snapshot averaging, requiring multiple signal samples. This presentation investigates the improvement offered by the cubic autoproduct for low SNR beamforming with a single snapshot. Prior work has demonstrated the utility of a quadratic product of complex field amplitudes within the signal bandwidth for beamforming and matched field applications. This quadratic field product, known as the frequency-difference autoproduct, is a synthetic estimate of an acoustic field at the difference frequency of the two constituent fields. That formulation is extended here to a cubic product of three complex field amplitudes within the signal bandwidth, termed the cubic autoproduct, capable of mimicking field content at frequencies below, above, and within the signal bandwidth. Important features and the mathematical description of the cubic autoproduct are reviewed before discussing the beamforming approach. Single snapshot beamforming results from experimental data, acquired in a noisy underwater environment, are directly compared between the cubic frequency-difference autoproduct and the acoustic field. [Work supported by ONR and by the US DoD through an NDSEG Fellowship.]
The Prufer transform for the calculation of acoustic normal modes
Authors: Baggeroer Arthur B.
Published: November 2022

The PrüferTransform for the Sturm-Liouvile (SL) equation was introduced by Prüferin 1923. An excellent reference is Numerical Solutions of Sturm-Liouville Problems by Pryce. Porter in Computational Ocean Acoustics introduced it to ocean acoustics. This author stumbled upon working on state variables at CMRE on 1978. The method derives first order equations for the phase and log-magnitude for second order equation in a phase plane. The essential feature is the phase equation is not coupled to the magnitude, so it may be solved as a nonlinear, first order equation and the surface boundary condition leads to a unique solution. New results for normal modes using the Prüfermethod are introduced. i) equations for the phase shifts and log-magnitudes at layer boundaries such as at the seabed; ii) state variable transformations based upon Ricatti equations and requiring evaluating one transcendental quantity, important for numerical methods; iii) issues of numerical stability for coupling the phase solution across the potential barriers of local sound speed maxima and poorly coupled boundaries; iv) an equation for computing the imaginary part leading to modal attenuation’s. The method is fast has survived many students using it, even those writing Matlab versions.
Alternating projections-based gridless compressive beamforming with co-prime arrays
Authors: Park Yongsung , Gerstoft Peter
Published: November 2022

Direction-of-arrivals (DOAs) estimation, beamforming, retrieves the angles of several sources from the outputs of receiving a sensor array. Compressive beamforming is a sparse signal recovery approach and has shown superior performance on DOA estimation. To overcome the angular searching grid issue, gridless techniques have been proposed. Most methods require a uniform linear array and use standard convex solvers that are computationally expensive. We propose a gridless compressive beamformer based on alternating projections. This method estimates DOAs by projecting a solution matrix alternatively. One projection works for measured-data-fitting, and the other works for having sparse DOAs. Our approach improves speed and accuracy and deals with arbitrary-shaped linear arrays. We validate the method using experimental data and test the DOA performance for a single snapshot, multiple snapshots with coherent arrivals, and co-prime arrays, a well-known non-uniform array.
Sound speed profile estimation in a thick mud layer from travel time data
Authors: Holland Charles W.
Published: November 2022

The sound speed profile in a surficial mud layer is of importance because it controls what is acoustically illuminated within and below the mud layer. A variety of estimates have been made at the New England Mud Patch (NEMP) with some near-surface sound speed gradients as large as 10 s−1 and larger. Here, single bounce seabed reflection travel time data are used to infer what mud sound speed gradients are and are not plausible near the central NEMP region where the mud thickness is ∼10 m. Time series data were collected on a moored hydrophone from a broadband source with a 1 second repetition rate as the tow ship transited on a radial from the hydrophone to a distance of ∼1 km at a speed of 2 m/s. The water column was essentially isovelocity and grazing angles ranged from 4.5° to 84°. It is known that at the base of the mud, there is a mud-sand transition layer (of order 1 m thick) where sound speed gradients can be large. However, above this layer, the travel time data clearly indicate that a mud 10 s−1 sound speed gradient is too large. [Research supported by ONR Ocean Acoustics Program.]
Augmented active acoustics: Recent experiences in acoustical enhancement for modern musical performance
Authors: Henderson Paul
Published: November 2022

Electronic acoustic enhancement systems allow the designer to implement traits not easily obtained with physical construction, or to provide variable room behavior to accommodate different program needs in a multi-purpose facility. Traditionally, most active acoustic systems have been employed for the enhancement of acoustic music, speech, and other classical program material. Here, we provide an overview of active enhancement methods particularly suited to contemporary, amplified musical performances. By accurately modeling and simulating the geometry of the performance space, naturally occurring reflection paths may be augmented with their synthetic counterparts, each rendered with high spatial fidelity but modified acoustic properties. Material characteristics may then be selected beyond what is practical in the built environment, and room signatures may be modified and changed over time. Real-time signal processing placed in-line with an audio mixing console then renders these sound fields into a collection of loudspeakers throughout the listening space. Examples are provided of auditoria where these systems have been installed, along with measured acoustical behavior demonstrating both the effectiveness of the technique and practical design constraints for implementation.
Transcranial focused ultrasound as a treatment for hypertension
Authors: Lea-Banks Harriet , Chauhan Neha , Hynynen Kullervo
Published: November 2022

Pharmaceuticals currently used for reducing blood pressure prove ineffective for many patients. As well, although hypertension is the most common disorder in pregnancy, many anti-hypertension drugs pose significant risks associated with restricted fetal growth, decreased uteroplacental blood flow, and fetal loss. Deep brain stimulation of the periaqueductal gray (PAG) region has shown promise in treating drug-resistant hypertension in patients. However, a non-invasive approach would carry far fewer risks, particularly during pregnancy. Our work has explored the potential of focused ultrasound (FUS), targeted to the PAG region, to reduce blood pressure. In a rodent model of hypertension, FUS delivered to the PAG successfully reduced high blood pressure to within the normal range. By comparing treatment regimes, we have also investigated the mechanisms underlying this reduction in blood pressure and ways to prolong the effect. This approach could point towards a new treatment for hypertension that has greater safety and broader applicability for vulnerable patient populations.
Emerging applications of image-guided therapeutic ultrasound for brain tumor-directed immunomodulation and immunotherapy
Authors: Sheybani Natasha D.
Published: November 2022

Immunotherapy has been established as a disruptive pillar of cancer treatment. However, the impact of immunotherapy has yet to be fully realized in neuro-oncology owing to the unique physical barriers (i.e., blood brain/tumor barriers [BBB/BTB]) and distinct immune microenvironment within brain tumors. These obstacles may be overcome through the alliance of image-guided interventions, such as therapeutic ultrasound, with immunotherapies. Specifically, transient disruption of the BBB/BTB via focused ultrasound (FUS) and circulating microbubbles is a promising strategy for potentiating immunotherapy through both immuno-modulation and drug delivery – notably, in a non-invasive, non-ionizing, and precisely targeted manner. We have demonstrated that FUS BBB/BTB disruption invokes mild, transient shifts in the immune milieu of brain tumor-bearing mice. Additionally, we have leveraged immuno-PET imaging to rationally deploy a therapeutic approach combining innate immune checkpoint inhibitor delivery with FUS. We show that this immunoPET-informed paradigm achieves superlative targeted antibody delivery and improved therapeutic outcomes in murine glioblastomas, with markedly reduced systemic antibody dose. Our ongoing investigations seek to advance the nexus of FUS, molecular imaging, and biomarker discovery with the goal of enabling non-invasive, precision immunotherapy paradigms for brain tumors.
Image guidance and beam localization for transcranial focused ultrasound therapy
Authors: Phipps Marshal A. , Manuel Thomas J. , Sigona Michelle K. , Luo Huiwen , Yang Pai-Feng , Newton Allen , Chen Li Min , Grissom Will , Caskey Charles F.
Published: November 2022

Therapeutic uses of transcranial focused ultrasound (tFUS) in the brain are being widely explored in both clinical and research settings from tissue destruction to blood brain barrier opening (BBBO) to neuromodulation. The appeal of tFUS is the ability to target structures throughout the brain with a millimeter scale focus. In order to understand the outcome of the treatment or experiment it is important to ensure the tFUS beam is targeted to and located at the region of interest. Image guidance allows for targeting of anatomical or functional structures within the brain. Here we present a targeting and localization scheme where optical tracking of the transducer is used to target the tFUS focus to a brain region within a previously acquired image and MR acoustic radiation force imaging is used to localize the beam in the brain to ensure the focus is at the target. By combining this targeting and localization scheme with a phased array transducer we are able to then steer the focus to ensure accurate sonications of specific brain regions using tFUS. This talk will discuss the application of this method to two different phased array transducers used for neuromodulation and BBBO in nonhuman primates.
Localization and quantification of the acoustical power of lightning flashes
Authors: Bestard Damien , Farges Thomas , Coulouvrat Francois
Published: November 2022

Lightning is an ubiquitous source of infrasound, and an essential climate variable. To observe lightning flashes, thunder measurement efficiently complements electromagnetic methods. Using acoustical arrays, time delays between sensors inform on the direction of sound arrival, while the difference between emission time and sound arrival provides the source distance. Combining two allows a geometrical reconstruction of lightning flashes viewed as sets of sound sources. The measured sound amplitude can also be back-propagated, compensating for absorption and density stratification. This allows us to evaluate the acoustical power of each detected source and the total power of an individual flash. This methodology has been carried out to analyse data from two campaigns in Southern continental France in 2012 and in Corsica in 2018. In Corsica, power from reconstructed sources could also be forward-propagated towards several isolated microphones and compared to measurement there, providing an additional validation of the method. A large number of events from the two campaigns has been analysed, including negative and positive cloud to ground discharges and intra-cloud ones. The analysis outlines the method efficiency, and the strong variability of lightning as sound sources, in terms of both power spatial distribution and global values.
Numerical modeling of infrasound propagation in a stratified atmosphere with small-scale inhomogeneities
Authors: Khodr Codor , Dragna Didier , Blanc-Benon Philippe , Marchiano Régis , Aubry Ludovic , Gainville Olaf , Millet Christophe
Published: November 2022

A major focus in infrasound research is the inclusion of realistic atmospheric flows in numerical propagation models. This usually encompasses temperature gradients and horizontal wind components, which create atmospheric waveguides. Additionally, gravity waves lead to small-scale variations of the ambient wind in the middle atmosphere, between 10 and 100 km in altitude. Using an internal gravity wave model from the literature [Gardner, J. Atmos. Terr. Phys. (1996)], we parametrize random fluctuations of the wind profiles, where the initial background state is based on a published case study [Sabatini et al., J. Acoust. Soc. Am. (2016)]. Acoustic propagation from an impulsive point source located at the ground is then modelled with solvers of the PLetma package [Khodr et al., J. Acoust. Soc. Am. (2021)], namely, ray tracing, normal modes, one-way equation and FDTD, for frequencies higher than 0.01 Hz. Cases with and without wind are considered, and propagation effects are investigated by a sensitivity analysis on source parameters and characteristics of the gravity wave. [This work was conducted within the framework of LETMA, a Contractual Research Laboratory shared between CEA, CNRS, Ecole Centrale de Lyon, C-Innov, and Sorbonne Université.]
The Las Vegas infrasound array: Long term deployments for the characterization of urban environments
Authors: Dannemann Dugick Fransiska , Wynn Nora , Bird Elijah , Bowman Daniel , Wright Melissa , Seastrand Douglas , Lees Jonathan
Published: November 2022

The Las Vegas Infrasound Array (LVIA) is a network of eleven infrasound sensors deployed from November 2019 through September 2022. While ambient infrasound noise in high and low-noise rural environments has been well characterized, little attention has focused on similar characterization in urban areas with presumed higher background noise levels. The LVIA long-term deployment provides an unprecedented opportunity to study urban infrasound and low frequency audio (20–500 Hz). In addition, large scale shutdowns due to the COVID-19 pandemic provide the ability to discriminate between background noise sources as closures reduced human-generated noise while natural signals remained stable. Within this presentation we will provide an overview of the LVIA installation, focusing on data quality. In addition, we will discuss comprehensive background noise models in urban regions, focusing on presenting probability density functions (PDFs) and median, 5th percentile, and 95th percentile amplitude values to evaluate variations in frequency and amplitude. We will summarize observed trends in background noise over time, highlighting sharp declines in acoustic power following COVID-19 shutdowns. Both sets of analyses will be combined to evaluate periodicities in urban acoustics throughout the city of Las Vegas. [ SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.]
Favorite problems on acoustic transducers and linear systems theory
Authors: Wilson Preston S.
Published: November 2022

Practitioners of acoustics sometimes forget how lucky we are that the vast majority of acoustic phenomena and devices we encounter in daily life are linear and solutions using linear systems theory work very well for predicting behavior and designing devices. Typical examples are microphones, loudspeakers and acoustic propagation at sufficiently low excitation levels. One might contrast this to a viscous dashpot, which is also commonly modeled as a linear device. The sliding seals in all viscous dashpots render them essentially-nonlinear from the start. One favorite problem I give year after year, in various forms, is reported here. A generic acoustic transducer, based on a linear simple harmonic oscillator is presented and often the system response function is given in the problem statement. Derivation of the transfer function could be a problem from earlier or later in the class. The students are asked to predict the time domain output of the transducer, subject to a periodic forcing composed of a sawtooth wave, using frequency-domain convolution and Fourier series. Various sub-questions explore the effect of transducer bandwidth and damping on the output signal. A variation of this problem using time-domain convolution is also a favorite. Predictions can be compared to measurements.
When is a Pepsi® can more than just a beverage container? When it is the inspiration for an acoustics homework problem!
Authors: Russell Daniel A.
Published: November 2022

When teaching acoustics to graduate students, some of most effective homework problems require students to compare multiples approaches, combine concepts from related topics, and evaluate numerical answers using experimental data. A problem from David T. Blackstock’s Fundamentals of Physical Acoustics textbook asks students to model an empty beverage can as a Helmholtz resonator, first using the simple formula and the measured dimensions of a real can. Then, students are asked to evaluate whether the simple formula is valid and to provide a more accurate solution if it is not. Most students find an improved impedance approach solution which changes the calculated frequency by approximately 9%. However, most students fail to realize that this problem is exactly analogous to the problem of elastic longitudinal waves in a fixed, mass-loaded bar, with the related first approximation of a simple mass-spring system in which 1/3 of the spring’s mass must be included. Further challenges arise when students attempt to measure the resonance of the empty can and obtain a measured frequency (with damping) that does not match calculated values. The pop-can resonator problem, its analogues, and some experimental challenges will be discussed in detail.
Non-reciprocity and roton dispersion in non-local piezoelectric metamaterials
Authors: Sugino Christopher
Published: November 2022

This talk will investigate the behavior of piezoelectric acoustic metamaterials with non-local circuit interactions, demonstrating that unbalanced, directional interactions yield non-reciprocal, roton-type dispersion behavior. The coupling between mechanical and electrical domains introduces additional dispersion branches whose periodicity is determined by the non-local circuit spacing. When these branches intersect the original dispersion curves of the system, non-reciprocal band gaps are opened in the mechanical domain. Furthermore, although the system is non-Hermitian, the appropriate use of local electrical resistance ensures that all dispersion branches are stable. This offers a practical alternative to realize non-reciprocal propagation that does not rely on nonlinearity or time-varying components, but instead on well-established directional electrical circuits. Numerical simulations show that the strength and spacing of the non-local interactions determines the frequency of non-reciprocity, providing a straightforward mechanism to program the dispersion properties of the system. The talk will conclude with preliminary experimental results and a discussion of system stability.
Topology optimization design of elastodynamic metasurfaces based on resonance gaps and antiresonance matching
Authors: Giraldo Guzman Daniel , Frecker Mary , Shokouhi Parisa
Published: November 2022

Elastodynamic locally resonant metasurfaces have emerged as effective means to control low-frequency Lamb and Rayleigh wave propagation. Currently, the design of these metasurfaces is typically achieved through experimentation and parameter tuning; no systematic design methodology has been established. In this work, a topology optimization-based design methodology is developed to tailor resonance and antiresonance frequencies of local resonators which compose locally resonant metasurfaces. The optimization seeks to match the antiresonance frequency to the bandgap’s desired central frequency while a resonance gap around that target frequency is sought to widen the bandgap. Both the antiresonance matching and the resonance gap are included in the optimization problem formulation. The objective function minimizes the difference between antiresonance eigenfrequencies and a target frequency while maximizing the difference between resonance eigenfrequencies and the target. A numerical case study is presented, in which an array of topology-optimized resonators placed over a surface is shown to effectively prevent the propagation of Rayleigh waves over a wide range of frequencies around the target design frequency.
Low tone bias during perception of period doubling
Authors: Huang Yaqian
Published: November 2022

Period-doubled voice consists of two alternating periods with multiple frequencies and is often perceived as rough with an indeterminate pitch. Past pitch-matching studies in period-doubled voice found that the perceived pitch was lower as the degree of amplitude and frequency modulation between the two alternating periods increased. The perceptual outcome also differed across f0s and modulation types: a lower f0 prompted earlier identification of a lower pitch, and the matched pitch dropped more quickly in frequency- than amplitude-modulated tokens (Sun & Xu, 2002; Bergan & Titze, 2001). However, it is unclear how listeners perceive period doubling when identifying linguistic tones. In an artificial language learning paradigm, this study used resynthesized stimuli with alternating amplitudes and/or frequencies of varying degrees, based on a production study of period-doubled voice (Huang, 2022). Listeners were native speakers of English and Mandarin. We confirm the positive relationship between the modulation degree and the proportion of low tones heard, and find that frequency modulation biased listeners to choose more low-tone options than amplitude modulation. However, a higher f0 (300 Hz) leads to a low-tone percept in more amplitude-modulated tokens than a lower f0 (200 Hz). Both English and Mandarin listeners behaved similarly, suggesting that pitch perception during period doubling is not language-specific. Furthermore, period doubling is predicted to signal low tones in languages, even when the f0 is high.
Learning from a single cue: Is phonetic learning dimension-based?
Authors: Idemaru Kaori , Bramlett Adam A. , Kapatsinski Vsevolod
Published: November 2022

Phonetic cue-weighting, the process of altering the weights of certain dimensions (e.g., F0) in the speech signal, is a fundamental process in speech perception. Cue-reweighting is the process of adaptation required for understanding new accents and learning second language speech contrasts; however, little is understood about the underlying mechanisms. Harmon et al. (2019) examined three candidate mechanisms (distributional, supervised, and reinforcement learning) showing evidence for reinforcement learning. The current study investigates Harmon et al.’s (2019) assumed phonetic dimensions by asking how a single cue in a phonetic dimension (e.g., a single voice onset time (VOT) value) of a phonological contrast ([b]/[p]) generalizes to other values of the phonetic dimension. Said simpler, is phonetic learning dimension-based? Native English listeners (N = 270) participated in an online perceptual training experiment in which participants were asked to identify word contrasts like pear and bear. Results suggest that learning to downweigh a cue (e.g., VOT = 5 ms) for [b]/[p] generalizes across new VOT values (e.g., VOT = 15 ms). However, the generalization did not extend to the most distant value (e.g., VOT = 35 ms). That is, cue-reweighting can affect a single phonetic category but does not extend to the entire phonetic dimension across category boundaries.