bluuebunny/crossref_metadata_2025 huggingface dataset:
Gene miaA for post‐transcriptional modification of tRNAXXA is important for morphological and metabolic differentiation in Streptomyces
Authors: Koshla Oksana , Yushchuk Oleksandr , Ostash Iryna , Dacyuk Yuriy , Myronovskyi Maksym , Jäger Gunilla , Süssmuth Roderich D. , Luzhetskyy Andriy , Byström Anders , Kirsebom Leif A. , Ostash Bohdan
Published: April 2019

Members of actinobacterial genus Streptomyces possess a sophisticated life cycle and are the deepest source of bioactive secondary metabolites. Although morphogenesis and secondary metabolism are subject to transcriptional co‐regulation, streptomycetes employ an additional mechanism to initiate the aforementioned processes. This mechanism is based on delayed translation of rare leucyl codon UUA by the only cognate tRNALeuUAA (encoded by bldA). The bldA–based genetic switch is an extensively documented example of translational regulation in Streptomyces. Yet, after five decades since the discovery of bldA, factors that shape its function and peculiar conditionality remained elusive. Here we address the hypothesis that post‐transcriptional tRNA modifications play a role in tRNA‐based mechanisms of translational control in Streptomyces. Particularly, we studied two Streptomyces albus J1074 genes, XNR_1074 (miaA) and XNR_1078 (miaB), encoding tRNA (adenosine(37)‐N6)‐dimethylallyltransferase and tRNA (N6‐isopentenyl adenosine(37)‐C2)‐methylthiotransferase respectively. These enzymes produce, in a sequential manner, a hypermodified ms2i6A37 residue in most of the A36‐A37‐containing tRNAs. We show that miaB and especially miaA null mutant of S. albus possess altered morphogenesis and secondary metabolism. We provide genetic evidence that miaA deficiency impacts translational level of gene expression, most likely through impaired decoding of codons UXX and UUA in particular.
Individual performance in a coopetitive R&D alliance: motivation, opportunity and ability
Authors: Wang Xiao , Dolfsma Wilfred , van der Bij Hans
Published: April 2019

This study examines individual knowledge sharing in a coopetitive R&D alliance. R&D is increasingly carried out in an R&D alliance setting, where individuals share highly specialized tacit knowledge crossing firm boundaries. A particular challenging setting is the coopetitive R&D alliance, where partner firms partially compete and individuals may leak competitive knowledge. This setting has been studied on the level of the partner firm. We want to deepen insights by examining the individual level. Drawing on the motivation‐opportunity‐ability framework, we study the influence of individuals’ job experience (ability) on their performance in the alliance. We also examine effects of two‐ and three‐way interactions between job experience, a central position in the social alliance network (opportunity) and intrinsic and extrinsic motivation. We find a positive association of job experience with individual performance, a positive interaction between job experience and extrinsic motivation and a positive three‐way interaction between job experience, central network position and intrinsic motivation, and discuss the impact of these findings.
Leveraging open innovation to improve society: past achievements and future trajectories
Authors: Ahn Joon Mo , Roijakkers Nadine , Fini Riccardo , Mortara Letizia
Published: April 2019

Open innovation (OI) is an approach which describes a purposive attempt to draw together knowledge from different contributors to develop and exploit innovation. It has become clear that OI directly benefits organisations' economic performance and resilience, but researchers, practitioners, and policy makers became also convinced that OI might be the way forward to tackle the world’s most pressing societal challenges, representing unresolved Grand Challenges, which can only be weathered by diverse sets of collaborative partners that join forces. Although anecdotal evidence points at how OI practices can be employed to achieve societal impact not only in private firms but also in public organisations, very little understanding exists ‐beyond anecdotal‐ to link OI to societal impact. This special issue has the ambition to start the discussion and establish a framework as the stepping stone to tackle this complex research gap.
The motivational unconscious
Authors: Kihlstrom John F.
Published: April 2019

Motives may be said to be unconscious in a variety of ways. They may be automatically and unconsciously elicited by consciously perceptible situational cues; they may be instigated by cues that are themselves excluded from conscious awareness, as expressions of implicit perception or memory; or the person may be consciously unaware of his or her actual motivational state. The paper reviews the evidence pertaining to all three aspects of unconscious motivation, with emphasis on conceptual and methodological questions that arise in the study of motives which are not accessible to phenomenal awareness or voluntary control but nonetheless influence the individual's experience, thought, and action.
Social mobility of ethnic minority students in Laos
Authors: Faming Manynooch
Published: April 2019

Idealistically speaking, schools are engines for upward social mobility. Education for ethnic minorities in Laos was set up to achieve nationalist, political, economic and sociocultural goals of ‘equity’ and ‘equality’. It was hoped that education would shift ethnic minorities from a lifestyle based on superstitious beliefs to a modern one, so that they could participate and enjoy ‘equality’ through educational equity. The purpose of this paper is to provide a case study of how equality as a promise in education has impacted on students’ upward mobility, particularly the political discourse of the ‘big man’. This paper explores social mobility provided by national education for ethnic minorities through boarding schooling. It finds that such education has yet to reposition ethnic minorities into the ethnic Lao sociocultural hierarchy. As a result, regardless of their educational success, students are still ranked as ‘ethnic minorities’ and as being ‘poor’ in the eyes of urban students, middle class and rich students, and the ethnic Lao elite.
Análisis de conocimientos durante sesiones educativas de sensibilización para el alivio del dolor, en el marco del proceso de acreditación: lecciones aprendidas
Authors: Rincon Montaña Marian Camila , Bonilla Ramirez Antonio Jose , Moreno Martinez Diego Alberto , Claici Anna
Published: April 2019

Introducción: Los vacíos de conocimiento del personal de salud pueden generar resultados negativos en la detección, valoración y manejo integral para el alivio del dolor. Este trabajo los pone en evidencia y muestra cómo un proceso de acreditación en salud diagnostica problemas y genera planes de mejoramiento. Objetivo: Analizar los conocimientos respecto al alivio del dolor en el personal de salud durante un proceso de acreditación, para lograr estándares de calidad. Materiales y métodos: Se realizó un estudio observacional con 358 encuestas al personal de salud de un hospital de alta complejidad, donde se evaluó la percepción sobre la importancia, seguimiento y tratamiento para el alivio del dolor. Resultados: En congruencia con la literatura mundial, el 61,9% de los participantes percibe que hay un inadecuado tratamiento del dolor intrahospitalario. Al detectarlo, el 55,3% de las veces se toma una conducta para aliviarlo. Un 22% piensa que los opioides son solo de uso por clínica de dolor, y el 33%, que todos los pacientes con dolor deberían ser evaluados por clínica de dolor. Conclusión: Aunque el alivio del dolor se percibe como un elemento importante, se diagnostican vacíos en el conocimiento que son susceptibles de intervención para optimizar la calidad de la atención.
Maximum Power Tracking and Current Control for Solar Photovoltaic System Applications, Hybrid Dynamical System Approach
Authors: Dali Ali , Diaf Said , Tadjine Mohamed
Published: April 2019

The problem of a DC-DC buck converter control to extract the maximum power from a photovoltaic (PV) system is considered in this paper. A controller is proposed based on the hybrid dynamical system approach dealing with both voltage and current control. This approach allows the system to track a desired voltage using the maximum power point tracking (MPPT) algorithm while keeping the output current at a moderate level. The stability of the closed loop of the full system is demonstrated by means of Lyapunov theory. The simulation utilizes realistic PV array parameters obtained using particle swarm optimization (PSO) identification algorithm. Experimental results are also presented showing the good performance of the proposed controller.
Energy Savings in Desalination Technologies: Reducing Entropy Generation by Transport Processes
Authors: Lienhard V John H.
Published: April 2019

Desalination systems can be conceptualized as power cycles in which the useful work output is the work of separation of fresh water from saline water. In this framing, thermodynamic analysis provides powerful tools for raising energy efficiency. This paper discusses the use of entropy generation minimization for a spectrum of desalination technologies, including those based on reverse osmosis (RO), humidification–dehumidification (HDH), membrane distillation (MD), electrodialysis (ED), and forward osmosis (FO). Heat and mass transfer are the primary causes of entropy production in these systems. The energy efficiency of desalination is shown to be maximized when entropy generation is minimized. Equipartitioning of entropy generation is considered and applied. The mechanisms of entropy generation are characterized, including the identification of major causes of irreversibility. Methods to limit discarded exergy are also identified. Prospects and technology development needs for further improvement are mentioned briefly.
Static and Dynamic Transmission Error Measurements of Helical Gear Pairs With Various Tooth Modifications
Authors: Benatar M. , Handschuh M. , Kahraman A. , Talbot D.
Published: April 2019

This paper presents a set of motion transmission error data for a family of helical gears having different profile and lead modifications operated under both low-speed (quasi-static) and dynamic conditions. A power circulatory test machine is used along with encoder and accelerometer-based transmission error measurement systems to quantify motion transmission behavior within wide ranges of torque and speed. Results of these experiments indicate that the tooth modifications impact the resultant static and dynamic transmission error amplitudes significantly. A design load is shown to exist for each gear pair of different modifications where static transmission error amplitude is minimum. Forced response curves and waterfall plots are presented to demonstrate that the helical gear pairs tested act linearly with no signs of nonlinear behavior such as tooth contact separations. Furthermore, static and dynamic transmission error amplitudes are observed to be nearly proportional, suggesting that static transmission error can be employed in helical gear dynamic models as the main gear mesh excitation. The data presented here is intended to fill a void in the literature by providing means for validation of load distribution and dynamic models of helical gear pairs.
Exploring the Tactor Configurations of Vibrotactile Feedback Systems for Use in Lower-Limb Prostheses1
Authors: Shi Sam , Leineweber Matthew J. , Andrysek Jan
Published: April 2019

Vibrotactile feedback may be able to compensate for the loss of sensory input in lower-limb prosthesis users to improve the mobility function. Designing an effective vibrotactile feedback system requires that users are able to perceive and respond to vibrotactile stimuli correctly and in a timely manner. Our study explored four key tactor configuration variables (i.e., tactors’ prosthetic layer, vibration intensity, prosthetic pressure, and spacing between adjacent tactors) through two experiments. The vibration propagation experiment investigated the effects of tactor configurations on vibration amplitude at the prosthesis–limb interface. Results revealed a positive relationship between vibration amplitude and intensity and a weak relationship between vibration amplitude and prosthetic pressure. Highest vibration amplitudes were observed when the tactor was located on the inner socket layer. The second experiment involving a sample of ten able-bodied and three amputee subjects investigated the effects of tactor configurations on user perception measured by response time, accuracy identifying tactors’ stimulation patterns, and spatial error in locating the tactors. Results showed that placing the tactors on the inner socket layer, greater spacing between adjacent tactors, and higher vibration intensity resulted in better user perception. The above findings can be directly applied to the design of vibrotactile feedback systems to increase the user response accuracy and decrease the response time required for dynamic tasks such as gait. They can also help to inform future clinical trials informing the optimization of tactor configuration variables.
Sonic boom propagation around a large building using a combined ray tracing/radiosity method
Authors: Riegel Kimberly A. , Sparrow Victor W.
Published: April 2019

The topic of supersonic flight over land is being investigated by scientists and regulators alike. The study of how the sonic boom behaves in and around buildings is of particular interest because of the potential impact of the noise on humans. This study examines the sound field as modeled by a combined ray tracing/radiosity method for sonic booms around large structures. These simulations are compared with the data from the 2009 Sonic Booms on Big Structures (SonicBOBS) test that was performed by NASA at Edwards Air Force Base. The influence of the complexity of the facade features, absorption coefficients, and scattering coefficients are examined. The results show general agreement between the simulation and the measured data. It was also shown that including diffuse reflections in the model does not have a dramatic effect on the resulting signature and does not improve the comparisons with the measurements. Therefore, including diffuse reflections is not worth the additional computational cost for an isolated building.
Coping with the black swan in psychophysics
Authors: Shen Yi
Published: April 2019

Aberrant responses that are associated with lapses in attention and microsleeps during a behavioral experiment violate basic assumptions underlying signal detection theory. These responses (i.e., the black swan events) occur infrequently but could lead to severe biases in the estimated perceptual sensitivity (d’) and misinterpretations of the data. When adaptive procedures are used to estimate behavioral thresholds, performance lapses occurring early in an adaptive track may cause convergence failures. Moreover, microsleeps may become more frequent as the task difficulty decreases, leading to potential instabilities in common adaptive procedures. Through a series of Monte-Carlo simulations, the potential effects of performance lapses on typical psychophysical tasks (e.g., Yes/No, 2-alternative forced choice) were demonstrated. Several possible experimental and computational techniques to cope with performance lapses were investigated. These included (1) introducing additional parameters representing performance lapses into the psychometric model, (2) allowing a “Not Sure” response category, and (3) screening and removing the likely aberrant responses. These simulation studies provide useful guidelines to design adaptive psychophysical procedures for subject populations from which performance lapses are expected (e.g., young children and behaving animals).
The classification of spherical shells with varying thickness-to-radius ratios based on the auditory perceptive features
Authors: Li Xiukun , Wu Yushuang
Published: April 2019

The detection and classification of underwater objects are an important part of the coast and harbor security. For silent targets, active sonar is always employed, and then, the information contained in the scattering echo is extracted and applied. Previous studies are aimed at targets with varied shapes, and the classification of objects with similar shapes has yet to be studied comprehensively. To address this issue, the classification of spherical shells with varying thickness-to-radius ratios (TRRs) is studied. The numerical results indicate that spherical shells can be roughly divided into three classes (extremely thin, thin, and thick) according to their scattering components. In this work, the scattering features, especially auditory perceptive features for spherical shells with different TRRs, are extracted and analyzed. Then, the features are imputed into a support vector machine classifier. The simulation results of the recognition rates under different features and signal-to-noise ratios will be present and analyzed. This study provides a novel concept for the classification of silent underwater targets.
Biomedical acoustics research at the Image-Guided Ultrasound Therapeutics Laboratories
Authors: Holland Christy K. , Mast T. Douglas , Haworth Kevin J.
Published: April 2019

The Image-guided Ultrasound Therapeutic Laboratories (IgUTL) are located at the University of Cincinnati in the Heart, Lung, and Vascular Institute, a key component of efforts to align the UC College of Medicine and UC Health research, education, and clinical programs. These laboratories, directed by Christy K. Holland, comprise graduate and undergraduate students, postdoctoral fellows, physician-scientists, and clinical and scientific collaborators in fields including cardiology, neurosurgery, neurology, radiology, and emergency medicine. Holland’s research focuses on biomedical ultrasound including sonothrombolysis, ultrasound-mediated drug and bioactive gas delivery, development of echogenic liposomes, early detection of cardiovascular diseases, and ultrasound-image guided tissue ablation. Imaging algorithms incorporate both passive and active cavitation detection. The Biomedical Acoustics Laboratory within IgUTL, directed by T. Douglas Mast, investigates ultrasound imaging for therapy guidance, including echo decorrelation imaging for monitoring liver cancer ablation and real-time tracking of tongue motion for biofeedback in speech therapy. The Biomedical Ultrasonics and Cavitation Laboratory within IgUTL, directed by Kevin J. Haworth, employs ultrasound-mediated gas scavenging for image-guided treatment of cardiovascular disease, especially reperfusion injury. [Work supported by NIH Grants R01 NS047603, R01 HL135092, R01 HL133334, R01 CA158439, R01 DC017301, and K25 HL133452.]
Feedback control of acoustic musical instruments when the number of sensors and actuators differ
Authors: Berdahl Edgar J.
Published: April 2019

Actuated instruments can be created in a variety of ways. An interesting class of actuated instruments are feedback-controlled acoustic musical instruments. A robust way to create these is to employ pairs of collocated sensors and actuators, and then to use the feedback control to simulate virtual physical systems. In the linear and time-invariant case, this means that the feedback control functions can be designed to be positive real. Accordingly, the physical properties of the instrument can become adjustable via the feedback control. An interesting case arises when the number of actuators and sensors differ. The actuators and sensors can however still potentially be collocated, which will result in the individual transfer functions from the actuators to the sensors (e.g. the mobilities) in being positive real. Under some special cases, stable feedback control can still be attained for a wide variety of feedback gains. The Feedback Guitar serves as an interesting case study for this. It has one actuator, which is approximately collocated with six piezoelectric sensors, one for each string. Using any non-negative linear combination of the sensor signals, an approximately positive real mobility can be obtained, which can enable stable feedback control for a wide variety of feedback gains.
Metamaterials in musical acoustics: A modified frame drum
Authors: Bader Rolf , Fischer Jost L. , Münster Malte , Kontopidis Patrick
Published: April 2019

Acoustic metamaterials have properties not found in nature, like negative stiffness, cloaking behavior or frequency bandgap damping. This is achieved by complex geometries often constructed out of multiple subunits in sub-wavelength size. Although also musical instruments often have complex shapes, like guitar or piano soundboards with regular fan bracing, metamaterials have not explicitly been used here. As an example, a modified frame drum is proposed with increased sound possibilities by adding masses to the drum membrane arranged in a circle. Such structures have been shown to have cloaking behavior. Using microphone-array and laser interferometry measurements it is shown that such a drum has a frequency-dependent cloaking behavior. When struck at the center of the added circle most energy above about 400 Hz stays in the circle and decays strongly. Such a sound cannot be produced with a regular frame drum. When struck outside the circle the drum sounds very much like a regular drum without added masses. By gradually changing the playing position from the circle center towards the circle rim, frequencies above about 400 Hz are gradually added. Therefore such a modified frame drum has much more possible sounds and therefore ways of musical articulation.
Automatic transcription of solo audio into music notation
Authors: Lee Dong Hyun , Beauchamp James W.
Published: April 2019

Creating sheet music can be an arduous task for instrumentalists and vocalists who improvise. This problem can be solved by using a pitch detector that produces a MIDI data file. MIDI data is a good solution because it can be easily transformed into music notation by standard programs such as Logic Pro X or Finale. The authors have developed an open source C/UNIX-based program that automatically transforms a monophonic sound file into a playable MIDI file. Pitch (F0) detection is accomplished using a short-time autocorrelation algorithm. Successive F0’s that correspond to the same MIDI note number are combined to form notes. The minimum duration of each note is determined by the autocorrelation window size, which in our case is set to 0.03 s. To achieve a more accurate notation result, the program employs duration and RMS amplitude thresholds to exclude spurious notes from the MIDI data.
Nonlinear acoustics at Moscow State University
Authors: Sapozhnikov Oleg A. , Khokhlova Vera A.
Published: April 2019

The rapid development of nonlinear acoustics, which began in the second half of the 20th century, had several distinct centers in different countries, and one of them was M. V. Lomonosov Moscow State University (MSU) in Russia. From MSU came one of the basic equations in nonlinear acoustics—the Khokhlov-Zabolotskaya (KZ) equation, the 50th anniversary of which is celebrated this year [Sov. Phys. Acoust. 15(1), 35–40 (1969)]. By the 1960–1970s, the work conducted by Academician Rem Khokhlov and his colleagues made MSU a leading international center for nonlinear acoustics and, even more influentially, for nonlinear optics. Nonlinear optics at that time underwent rapid growth related to the invention of lasers, and many phenomena in optics had analogs in acoustics. One of them was a parabolic approximation for wave beams, which led to formulation of the KZ equation after translation to acoustics with consideration of the details of nonlinear effects in weakly dispersive media. Along with the development of theoretical foundations, initial experiments on nonlinear acoustic phenomena were carried out at MSU. The current paper highlights these studies, as well as contemporary work and achievements on nonlinear acoustics at Moscow State University.
Comparison of two ultrasonic backscatter coefficient methods under nonlinear distortion
Authors: Coila Andres , Oelze Michael
Published: April 2019

The backscatter coefficient (BSC) is a fundamental property of tissues and can be parameterized for tissue characterization. The BSC requires a reference signal, which is estimated through either the planar reflector method (PRM) or the reference phantom method (RPM). In both methods, linear acoustic propagation is assumed. In this work, the BSC estimation methods are evaluated when nonlinear distortion is present. RF data were acquired from two physical phantoms, labeled A and B, with a 5 MHz single-element transducer using low power (1 excitation level) and high power (6 increasing excitation levels) excitation signals. Phantom A contained glass beads with diameters ranging from 75 to 90 μm and phantom B had glass beads with diameters ranging from 9 to 43 μm. The BSCs estimated using the low power setting and high power settings were compared for the both the PRM and RPM through a root mean square error (RMSE). Estimates of the effective scatterer diameter (ESD) were obtained using each method for each high power setting and compared to the low power setting. The RMSE increased as the power setting increased with much higher RMSEs using the PRM compared to RPM, i.e., a maximum of 7.3 times larger for phantom A and 8.6 times larger for phantom B. Estimates of ESD matched the ranges of glass beads sizes for both phantoms except when using the PRM at higher power settings. These findings suggest that the RPM is more robust to nonlinear distortion effects compare to the PRM.
Psychophysical and anatomical evidence for hidden hearing loss in laboratory mice
Authors: Burke Kali , Screven Laurel A. , Kobrina Anastasiya , Schrode Katrina M. , Lauer Amanda , Dent Micheal L.
Published: April 2019

Exposure to high intensity sound can lead to temporary or permanent threshold shifts. Noise exposures that do not cause long-term hearing deficits, however, can induce extensive afferent ribbon synapse loss, while hair cells and spiral ganglion neurons remain mostly intact (Kujawa and Liberman, 2009). This loss of synapses despite normal hearing thresholds is referred to as hidden hearing loss (HHL). We examined the development of HHL in laboratory mice using operant conditioning with positive reinforcement. After exposing mice to 8–16 kHz narrowband noise at 100 dB SPL for 2 h, hearing thresholds temporarily shifted for both pure tone and ultrasonic vocalization stimuli; however, post-exposure thresholds and threshold shifts varied by sex and age. Immunohistochemistry and transmission electron microscopy were conducted to quantify peripheral damage and central synaptic reorganization once behavioral testing was complete. Brains were collected, sectioned, and labeled against VGLUT1 or GAD65 and labeling was quantified in the ventral cochlear nucleus. Cochleas were also collected, dissected, and labeled for myosin6 to label hair cells and either CTBP2 or SV2 to identify afferent or efferent terminals, respectively. Our findings show that mice are able to behaviorally recover hearing following non-traumatic noise exposure despite changes in peripheral and central auditory structures.
Physiological studies of binaural tone-in-noise detection in the inferior colliculus of awake rabbit
Authors: Fan Langchen , Henry Kenneth S. , Carney Laurel H.
Published: April 2019

With identical noise maskers presented to both ears, human listeners have lower tone detection thresholds when the tone is presented out-of-phase between the ears (N0Sπ) rather than in-phase (N0S0). The threshold difference is called the binaural masking level difference (BMLD). Human listeners have BMLDs up to at least 4 kHz, but previous studies to understand neural mechanisms have only used low-frequency tones. Here, we recorded single-neuron responses from the inferior colliculus in awake rabbit to a wide range of overall noise levels and tone frequencies near the neuron’s characteristic frequency. Maskers were 1/3-octave gaussian noise centered at the tone frequency. Neural thresholds at each noise level were estimated from average-rate responses at signal-to-noise ratios of -12 to +8 dB based on receiver-operating-characteristic analysis. Neural thresholds were similar across noise levels and were pooled together for further analysis. BMLDs of all recorded neurons with measurable thresholds for both N0S0 and N0Sπ ranged up to +17 dB (i.e., a substantial masking release for the N0Sπ condition). Across the population of neurons tuned to different frequencies, the largest BMLDs at each frequency decreased with increasing frequency, consistent with human psychophysical studies, but with a more gradual slope.
Rapid measurement of frequency depending spectro-temporal modulation detection thresholds
Authors: Klockgether Stefan , Rehmann Julia , Derleth R. Peter
Published: April 2019

The modulation detection threshold of spectro-temporal modulations (STM) is highly correlated with the speech reception threshold (SRT). A common interpretation of this correlation is that detection capability of concurrent spectral and temporal modulations is a measure for the frequency resolution power of the auditory system. The STM-detection threshold can be measured for different frequency regions by applying the modulation only to particular frequency bands. One could make an estimation of the frequency resolution power at those particular frequency regions. This could give a hint on a beginning or a hidden hearing loss which is not showing up clearly in an audiogram. This study shows different methods to rapidly measure STM-detection thresholds frequency dependent and compares the results with results gained with an established adaptive staircase method. The rapid methods are evaluated with regard to their practicability and the trade-off between reduced duration and reduced accuracy.
Pure-tone thresholds and the binaural masking level difference
Authors: Shub Daniel E. , Bernstein Joshua G. W. , Kubli Lina R. R. , Brungart Douglas S. , Grant Ken W.
Published: April 2019

Although several studies have examined the relationship between high-frequency pure-tone thresholds and the 500-Hz binaural masking level difference (BMLD), the results have not always been consistent. In this study, a retrospective analysis was conducted on an existing dataset from over 3000 military service members that included both pure-tone thresholds measured as part of their annual hearing conservation testing and a 33-trial clinical test of the BMLD. There was only a slight dependence of the 500-Hz BMLD on high-frequency pure-tone thresholds. For listeners with elevated pure-tone thresholds, this dependence was in good agreement with the findings of Jerger et al. [Arch. Otolaryngol. 110, 290–296 (1984)] and slightly larger than that reported by Wilson and Weakley [J. Am. Acad. Audiol. 16, 367–382 (2005)]. For listeners with near-normal hearing, the dependence of the 500-Hz BMLD on the 4-kHz pure-tone threshold was substantially less than that reported by Bernstein and Trahiotis [J. Acoust. Soc. Am. 140, 3540–3548 (2016)]. A possible explanation might be the degree of training offered to the subjects and procedural differences between clinical and laboratory techniques. [The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense, or U.S. Government.]
Blast exposure in the military and its effects on sensory and cognitive auditory processing
Authors: Bressler Scott , Jenkins Kimberly , Myers Jennifer , Grant Kenneth , Shinn-Cunningham Barbara
Published: April 2019

Blast-induced traumatic brain injury (TBI) and hearing loss are the two most common types of injuries sustained by military personnel while serving in the U.S. Global War on Terrorism. Recently several VA audiology clinics have reported active duty service members complaining of having problems communicating in noisy listening environments despite having normal to near-normal pure tone thresholds. In addition to standard clinical measures, we used electroencephalography (EEG) to determine whether damage to suprathreshold responding auditory nerve fibers in the sensory periphery and/or trauma to cortical regions associated with attention and working memory were responsible for the reported listening complications. In separate auditory and visual selective attention tasks, behavioral and neural measures suggest no evidence of long term neurotrauma affecting normal cognitive function. We found while absolute measures of auditory brainstem encoding varied greatly in all study subjects, comparisons of how the envelope following response (EFR) changes with modulation depth hint at differences between blast and non-blast exposed service members. These findings are consistent with audiometric threshold and distortion product otoacoustic emission data that show subtle differences between groups within clinically defined normal limits. Taken together these results suggest subclinical differences in audiometric measures might explain differences in suprathreshold listening.
Development of duration discrimination during adolescence
Authors: Gay Jennifer , Rosen Merri , Huyck Julia J.
Published: April 2019

Temporal processing, which is important for comprehending speech, matures over an extended developmental period. Here we investigated duration discrimination during adolescence. Listeners aged 8–19 years (four age groups) heard three broadband noises on each trial, and indicated which, if any, of the noises was different in length (longer or shorter). The broadband noises were 15, 30, 50, 100, or 200 ms in duration. During each of two sessions on consecutive days, each combination of stimulus durations (e.g., 15 vs. 100 ms) were presented a total of twenty times in pseudo-randomized order, including identical comparisons (e.g., 100 vs. 100 ms) to enable calculation of false alarm rates. All age groups showed a higher (better) sensitivity (d’) for comparisons whose durations were more different from one another (e.g., 15 vs. 200 ms). Nevertheless, duration discrimination abilities continued to develop up to age ~14 years: 8- to 10-year-olds did not differ from 11- to 13-year-olds, but 11- to 13-year-olds had lower sensitivity than 14- to 17-year-olds and young adults, who themselves did not differ from one another. There was no learning between sessions and the interactions were not significant. Thus, even simple duration discrimination abilities may continue to develop into adolescence.
Theoretical study of a metasurface-based sound absorber
Authors: Ji Jun , Sui Ni , Yan Xiang , Yuan Fuh-Gwo , Jing Yun
Published: April 2019

A metasurface-based sound absorber panel is proposed to achieve high sound absorption with a deep sub-wavelength thickness and a relatively broad bandwidth. The panel composed of different periodically-arranged Helmholtz resonators has been designed by a radiation impedance model which takes the mutual radiation impedance into account. Numerical simulations based on COMSOL Multiphysics show that the radiation impedance model yields more accurate results compared with the traditional equivalent surface impedance method. Broad bandwidth of sound absorption is achieved under proper coupling by carefully tuning the geometry and distance between Helmholtz resonators.
Transverse to longitudinal mode conversion via nonlinear inertial effects in a locally resonant metamaterial plate
Authors: Wallen Samuel P. , Haberman Michael R.
Published: April 2019

Acoustic and elastic metamaterials have potential for tailoring wave propagation in ways beyond the capabilities of conventional materials and have been shown to exhibit a myriad of rich dynamical effects, such as negative effective properties, cloaking, extreme damping, and non-reciprocity. However, most of the existing literature has been focused on linear dynamics in which these behaviors are restricted to narrow frequency bands. More recently, nonlinearity has been investigated as a method of increasing this bandwidth, as well as a means to broaden the palette of available dynamics. Past studies on nonlinear acoustic and elastic metamaterials have demonstrated effects not easily accessible in the linear regime, including harmonic generation, mode hopping and conversion, tunable band gaps, chaos, and intrinsic localized modes. In this work, we present a model for a nonlinear elastic plate metamaterial that exhibits mode conversion between transverse and longitudinal waves. The mode conversion is enabled by cantilevered beam attachments undergoing large-angle out-of-plane oscillations. By analyzing the unit cell of this locally-resonant plate, we interpret the transverse-longitudinal coupling as a nonlinear, anisotropic effective mass density. The mode conversion effect is demonstrated via direct numerical simulations. [Work supported by NSF and ARL:UT.]
Design, optimization, and fabrication of mechanical metamaterials for elastic wave control
Authors: Walsh Timothy F.
Published: April 2019

Harsh shock and vibration environments are commonly encountered in engineering applications involving dynamic loading. Acoustic/elastic metamaterials are showing significant potential as candidates for controlling wave propagation and isolating sensitive structural components. However, these materials have complex microstructures that must be properly designed to achieve their desired properties. In this talk we will present strategies for PDE-constrained design optimization of locally resonant elastic/acoustic metamaterials. We will present a variety of resonator geometries that can be easily optimized for wave control applications, along with fabrication details involving multi-material additive manufacturing. A variety of objective functions will be compared for their effectiveness in designing mechanical filters. Numerical examples will be presented for vibration isolation and acoustic cloaking applications. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Departmentof Energy's National Nuclear Security Administration. With main facilities in Albuquerque, NM, and Livermore, CA, Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.
Understanding acoustic-phonetic environments of prelingual children with cochlear implants: Challenges, tools, and insights
Authors: Dilley Laura
Published: April 2019

Variability in auditory and linguistic environments experienced by prelingual children with cochlear implants (CIs) potentially helps explain variation in their language outcomes. Here, results are presented from several studies from our lab investigating early acoustic-phonetic environments of children with CIs. One collaborative study conducted over 10 years investigated individual differences in acoustic-phonetic quality of maternal speech as predictors of language outcomes in children with CIs. Results showed that properties of maternal speech recorded in the lab—as indexed in part by measures derived from vowel formants and fundamental frequency—significantly predicted infants’ language outcomes and growth on multiple standardized assessments two years after cochlear implantation. Other work has examined the usefulness of a widely adopted commercial automatic speech processing technology—the Language ENvironment Analysis (LENA) system—for investigating individual differences in auditory environments. Results from our study suggested considerable variability across samples in LENA’s accuracy at identifying adult speech, limiting LENA’s value for investigating individual differences in acoustic-phonetic input to children with CIs. Finally, an update is provided on current work using combined signal processing and hand-coding approaches aimed at investigating variability in acoustic input to children with CIs in their home environments. [Work supported by NIH grant R01DC008581.]
The soundscape of music education
Authors: Siebein Gary W. , Tsaih Lucky S. , Paek Hyun , Roa Marylin , Miller Jennifer R. , Vetterick Matthew , Siebein Keely
Published: April 2019

Research on acoustical qualities of music education spaces based in soundscape theory provides a method to link the acoustical performance of a space with the instructional tasks that occur in the space with the architectural design features of the rooms. There has been limited study of the acoustical needs of teachers and students in music education spaces. Pirn (1978) showed that music practice rooms can become too loud as multiple musicians are placed in a closed and limited room volume without sufficient sound absorbing materials. Gade (1988) defined the characteristic of Support to measure cross room reflections from ceiling and wall surfaces to allow the musicians to hear each other. Tsaih (2011) found that the soundscape of music education was based on the ability of the students and teacher to be able to clearly understand spoken instruction and for students to hear each other and for the instructor to hear students playing in time, in tune and in dynamic. Case studies of music education spaces will illustrate how these concepts are integrated within the architectural design and acoustical analysis of the spaces.
A multidisciplinary music and visual arts center at Earlham College
Authors: Strong John T. , Giegold Carl
Published: April 2019

The Center for Visual and Performing Arts is a new construction on the campus of Earlham College, conceived as the new performance and rehearsal home for the Earlham Music department. It hosts a broad spectrum of ensemble types, including dedicated rehearsal spaces for jazz, percussion, and Javanese gamelan, and a full teaching studio and practice room suite. The flexible 260-seat Lingle Recital Hall hosts performances of small- to medium-sized ensembles; seating retracts to provide a flat floor rehearsal space for full orchestra and other large ensembles. An acoustically diffusive basket-weave wooden slat treatment around the lower perimeter of the room as well as variable acoustic systems spread throughout the hall allow a wide range of interior acoustic flexibility. The building also hosts a black box studio theater programmed by the Theater Arts department, and painting, textile, ceramics, and metalworking space for the Art department. Due to the building’s compact footprint, and the high sound levels produced by the ensembles and art workspaces, extensive structural and architectural acoustic isolation measures are utilized. A centrally located recording suite with connectivity to the major performance and rehearsal spaces also functions as a teaching space for the recording arts.
Armerding center for music and the arts at Wheaton College
Authors: Miller Gregory A. , Mayell Marcus R. , Schuette Dawn
Published: April 2019

Wheaton College has long cultivated young musicians in a tight-knit community outside of Chicago. As the program has grown in recent decades, however, the community has burst at the seams in need of expanded space for faculty and students alike. The construction of a new science building on campus led to the availability of Armerding Hall to be redeveloped into a new home for the Conservatory on the central campus quad. Shallow floor-to-floor heights and limited structural capacities led to acoustic isolation strategies that provide “just enough” separation between faculty studios and relied on careful detailing for success. A steeply-raked Lecture Hall was reimagined to become a 100-seat recital hall with volume carved into adjacent spaces. Other spaces within the building include ensemble rehearsal rooms, a recording suite, and a room for multi-media composition. A second phase of the project will include new construction of a 650-seat concert hall and the college’s first dedicated rehearsal hall for their formidable choral program.
Missouri State University—Ellis Hall
Authors: Corry Brian , Hull Kirsten , Myers Joseph W.
Published: April 2019

Missouri State University Ellis Hall is a 1957 modernist building originally designed for the music department. The building was mostly untouched over the years, despite poor sound isolation and unremarkable, undersized performance spaces. Kirkegaard worked closely with Patterhn Ives on a comprehensive renovation that included replacing the building mechanical systems and much of its exterior curtain wall. The interior is a virtual gut/rehabilitation, but wherever possible existing walls were incorporated into new sound-isolating assemblies to avoid unnecessary expense. The substantial scale of the project compared to the very limited budget required the design team to find carefully calibrated solutions for what to reuse and what to replace. One of the greatest challenges was to provide an acoustic superior recital hall, a goal that the School of Music emphasized as critical to the future of their program, from a renovation of the low-ceilinged existing recital hall. The solution was to demolish the hall's floor slab to capture the room volume from an under-used rehearsal room below, while preserving the upstage pipe organ and a handsome wood side wall. The result is a very successful new 240 seat recital hall in the shell of the old hall.
Data acquisition and controls for a bat robot
Authors: Walker Brandon , Sutlive Joseph , Müller Rolf
Published: April 2019

Robotic reproductions of the dynamic and adaptive nature of the biosonar systems found in many bat species require a capable back-end that is capable of integrating mechanical, acoustical, electrical, and computational functions in an efficient manner. This is particularly true when mimicking bat species that change the shapes of their noseleaves and pinna as part of their biosonar behaviors. To address the challenge of replicating these highly integrated functions, a platform consisting of commercial, off-the-shelf components, centered around a microcontroller (Arduino Due) and a single-board computer (Raspberry Pi 3) has been designed. The real-time microcontroller has been delegated the signal generation for the ultrasonic pulses and data acquisition for the echoes, as well as all control operations for the mechanical periphery of the robotic bat head. This includes synthesizing output waveforms, conditioning measured data, and maintaining the state of the pneumatic actuation systems. Commands are issued directly by the computer, which is responsible for orchestrating overall “behaviors” and managing the relevant data. In addition, the control system acquires and stores meta data for the echoes such as geospatial location and acquisition time. Future improvements to this system will seek to establish closed loop control liking echo analysis to peripheral dynamics.
Bio-inspired generalizable-focusing wideband FM sonar
Authors: Simmons James A. , Ming Chen
Published: April 2019

The bat’s inner ear and auditory brainstem register successive frequencies in FM sweeps of broadcasts and echoes with single spikes. Using the neural spectrogram of each broadcast as reference, spike latencies trace the FM sweeps for imaging echo delay by spectrogram correlation. If mutually-interfering glint reflections are present, the echo’s neural spectrogram has regularly-spaced ripples caused by amplitude-latency trading. Glint-delay estimates are generated by transforming the ripple pattern from frequency to time in real time using feedforward inhibition. Several glint delay estimates can coexist in focused target images before accumulation of nulls generates too many glint estimates and blurs the image. Echo lowpass filtering, characteristic of clutter, affects a wide swath of frequencies and changes the slope of the neural spectrogram, which evokes multiple nulls and causes image blurring that suppresses the clutter. Echo Doppler shifts also change the slope of the FM sweep, and the same mechanism is capable of blurring Doppler-shifted images so that troublesome ambiguity is suppressed. By internally adjusting the neural FM sweep of the broadcast reference, the images of echoes can be refocused onto any desired location not only in range, azimuth, and elevation, but also on the range-Doppler plane. [Work supported by ONR.]