bluuebunny/crossref_metadata_2025 huggingface dataset:
Comprehensive summary of the impulsive pile driving sound exposure study series
Authors: Halvorsen Michele B. , Casper Brandon M. , Popper Arthur N. , Carlson Thomas J.
Published: June 2017

The high intensity controlled impedance fluid filled wave tube (HICI-FT) was used to expose fishes, in the laboratory, to impulsive sound signals under controlled conditions. Fish species were exposed to pile driving signals under different experimental paradigms, followed by detailed investigations of their physiological tissue response (aka, barotrauma injuries). Most often the cumulative sound exposure level (SELcum) was held constant while varying the number of pile strikes and the single strike sound exposure level (SELss). Altering these three variables proved the equal energy hypothesis irrelevant; the higher SELss values with fewer number of strikes caused a highest injury levels. The first dose-response curve was generated for fish responses. Comparisons between different species showed fish with no swim bladder at low injury risk, fish with a closed swim bladder (physoclists) at a high injury risk, and fish with an open swim bladder (physostomes) at a moderate injury risk. If fish find safe haven in the wild, they have potential to heal within 10 days of receiving moderate injuries. Tissue injury appears to occur before damage to hair cells occurs. And most recently, fish show injury after exposure to as few as 8-impulsive signals that have a high SELss value.
Deployment of a passive acoustic collision alarm for autonomous underwater vehicles
Authors: Viquez Oscar A. , Fischell Erin M. , Schmidt Henrik
Published: June 2017

Autonomous underwater vehicles (AUVs) operate in increasingly busy environments, and avoiding collisions with ships is an important aspect of the vehicle's decision framework. Advances in low-cost AUV technology has further raised interest in solutions that minimize the need for specialized equipment. A proposed solution is to passively detect and track boats based on their noise. We have developed and demonstrated an algorithm that uses changes in acoustic power to estimate time to collision. A cylindrical propagation model is used for shallow-water environments, to relate measured power with range from a source. The time-derivative of this result is computed to estimate the time to closest approach, for a ship with unknown but constant acoustic source level. Experiments were performed with vessels of various characteristic frequencies and source levels. Acoustic measurements were recorded through off-the-shelf hydrophones. Estimates from the acoustic method were first compared with GPS-based measurements, and later with the AUV's on-board navigation data. Test missions were deployed to alter AUV behavior in response to approaching acoustic sources. Successful estimates and AUV responses were recorded, although improved signal processing and noise filtering is recommended for future implementations. [Work supported by Lincoln Laboratory and DARPA.]
The predictability of acoustic receptions on gliders in the Arctic
Authors: Van Uffelen Lora J. , Webster Sarah E. , Lee Craig M. , Freitag Lee E. , Worcester Peter F. , Dzieciuch Matthew
Published: June 2017

Acoustic transmissions from shallow sources in the Arctic Ocean can propagate several hundred kilometers due to the presence of an Arctic acoustic duct. Receptions of these long-range transmissions are complex patterns of arrivals which are strongly dependent upon upper ocean sound-speed structure. In addition to measuring sound-speed parameters, gliders equipped with acoustic recorders can measure these arrivals and can complement moored receptions, providing data at many ranges with respect to the moored sources. There is a higher degree of uncertainty in glider position compared with moored receivers, but localization can be improved in post-processing with enhanced acoustic predictability. Two acoustic Seagliders were deployed for a short pilot study in late Summer 2016 in the vicinity of an array of acoustic tomography sources with frequencies on the order of 250 Hz in the Arctic Ocean in anticipation of a longer deployment in Summer 2017. Source receptions recorded on the gliders are compared with acoustic predictions based on sound-speed profiles generated from environmental data collected on the gliders themselves to begin to understand the predictability of transmissions received on gliders in an Arctic environment. Acoustic predictions are analyzed for receptions both within the acoustic duct and at depths exceeding the acoustic duct.
Geoacoustic inversion to study spatial variability and uncertainty along a 14-km seabed survey on the Malta Plateau
Authors: Dettmer Jan , Holland Charles W. , Dosso Stan E. , Mandolesi Eric
Published: June 2017

Seabed variability of continental shelves is well understood at kilometer and centimeter scales; however, mesoscales of several meters are poorly understood. While vertical seismic profiling can provide insights into layer geometries, geoacoustic parameter values are not estimated, and structural images are averaged over ~100 m and typically distorted. Here, we apply automated sequential inversion to seabed reflectivity data recorded using an autonomous underwater vehicle (AUV) on the Malta Plateau. The AUV tows a 32-hydrophone array and a source emitting signals at regular intervals along a 14-km survey track in two frequency bands (900-1300 and 1900-3600 Hz). The reflection data are processed in terms of reflection coefficients which results in ~1600 data sets, each with a seabed footprint of <20 m. For efficient uncertainty quantification, a particle filter is applied. The inversion provides rich seabed information with resolution and geoacoustic parameter estimates significantly better than possible with vertical profiling. The survey reveals a low-velocity (<1500 m/s) wedge with low attenuation of initially 1.2-m thickness, thinning towards the Sicilian coast and disappearing after 8 km. An erosional, high-velocity boundary is increasingly buried by low-velocity material towards the coast. This boundary is rougher in shallower water and depressions are filled with material of lower velocity. [Data: CLUTTER JRP, a collaboration of ARL-PSU, DRDC, CMRE, and NRL. Research supported by SERDP and ONR ocean acoustics.]
Remarks on the definition of airborne sound insulation and consequences for uncertainties
Authors: Wittstock Volker
Published: June 2017

Airborne sound insulation is explicitly defined as the ratio between incident and transmitted sound power. Since sound power cannot be measured directly, field quantities like sound pressure are measured to derive the desired sound power. The relation between sound pressure and sound power depends on the nature of the sound field, i.e., to which extent it is a diffuse sound field. This is the main reason why it is impossible to derive an analytic equation for the measurement uncertainty of a sound power and thus of a sound insulation. The current practice is to define standardized test facilities for the measurement of airborne sound insulation. The uncertainty of measured sound insulations is then approximated by the standard deviation of reproducibility determined by interlaboratory tests. This is equivalent to changing the definition of airborne sound insulation. It is no longer the sound power ratio but the mean value of the sound insulation measured in very many or all thinkable laboratories meeting the required specifications. Thus, laboratory specifications become part of the definition of airborne sound insulation. The contribution highlights the background of the different definitions and shows consequences for the uncertainty of airborne sound insulation.
Importance of correlation between reverberation times for calculating the uncertainty of measurements according to ISO 354 and ISO 17497-1
Authors: Müller-Trapet Markus
Published: June 2017

The calculation of measurement uncertainties follows the law of error propagation as described in the Guide to the Expression of Uncertainty in Measurements (GUM). The result can be expressed as a contribution of the variances of the individual input quantities and an additional term related to the correlation between the input quantities. In practical applications, the correlations are usually neglected. This has, e.g., led to the expression included in Annex A of ISO 17497-1 to calculate the precision of the measurement of random-incidence scattering coefficients. To determine whether it is actually justified to neglect the input correlations, this contribution investigates the correlations between the reverberation times used to determine the random-incidence absorption coefficient (ISO 354) and scattering coefficient (ISO 17497-1) in a reverberation chamber. The data used here are taken from measurements in a real-scale and a small-scale reverberation chamber. It is found that for ISO 354 correlations can be neglected. However, for ISO 17497-1, it is important to take correlations into account to obtain the correct measurement uncertainty using error propagation.
Comparisons of laboratory repeatability and performance when increasing reverberation chamber volume
Authors: Winker Douglas , Stahke Brian , Black Michael C.
Published: June 2017

ETS-Lindgren/Acoustic Systems has operated an acoustics laboratory in Austin, Texas since 1985. The original laboratory consisted of a reverberation chamber suite with a source chamber volume of 200 cubic meters and a receive chamber volume of 254 cubic meters. In 2008, ETS-Lindgren/Acoustics Systems relocated and constructed a completely new laboratory. The new lab features a reverberation chamber suite with a source chamber volume of 208 cubic meters and a receive chamber volume of 408 cubic meters. During the transition, all measurement equipment, test frames, and proficiency specimens were maintained and are constant between both laboratories. Repeatability data for ASTM E90 and ASTM C423 will be discussed and compared for each laboratory reverberation chamber suite. The changes in the results will be shown with respect to the different chamber sizes. Proficiency panels constructed to ASTM round robin guidelines have been maintained since original construction and form the baseline for this comparison. Comparison of low-frequency performance between the two chamber sizes will be emphasized with respect to current reverberation construction guidelines and limits. Intra-laboratory uncertainties over time will also be discussed and compared to the published uncertainties of the ASTM E90 and C423 standards.
Update on the current ASTM building acoustics inter-laboratory studies
Authors: Golden Matthew V.
Published: June 2017

In the last few years, ASTM E33 committee on Building and Environmental Acoustics has undertaken a program to improve the precision and bias statements in its laboratory and field standards. This is done through analysis of inter-laboratory studies. At the time of writing, there are approximately 10 such inter-laboratory studies either currently in process or recently completed. This paper will give a brief overview of these activates. It will highlight those studies involving laboratory building acoustics standards, including standards on sound transmission loss, impact sound transmission, sound absorption in reverberation rooms, and sound attenuation between rooms sharing a common ceiling plenum.
Tools for the assessment of sound quality and quality of experience in original and simulated spaces for acoustic performances
Authors: Blauert Jens , Braasch Jonas , Raake Alexander
Published: June 2017

Sound quality and Quality of Experience are complex mental constructs. Their assessment, consequently, requires consideration of multiple different aspects, each of which may demand different evaluation and measurement methods going beyond current standards such as ISO 3382 for room acoustics. In this talk, relevant quality aspects are identified including signal-related, psychological, semiotic, and further cognitive ones. For each of them, available evaluation and measurement methods will be discussed, using the amount of abstraction involved as an ordering principle. Methods that can extract binaural cues from a running signal, such as those provided by BICAM (Binaurally Integrated Cross-correlation/Auto-correlation Mechanism) for room-impulse responses, or those provided by the TWO!EARS model framework (www.twoears.eu) will be highlighted, including consideration of the processing of cross-modal cues. A special focus will be put on the question of to which extent human assessors can be replaced with current algorithmic (instrumental) methods as based on computer models of the human hearing and subsequent cognitive processing. The task of collecting proper reference data will be considered, whereby results from the AABBA Initiative (Aural Assessment By means of Binaural Algorithms) and the TWO!EARS project (Reading the world with TWO!EARS) will be incorporated. [Work supported by FET-Open FP7-ICT-2013-C-618075 and NSF BCS-1539276.]
Do bioacoustic conditions reflect species diversity? A case study from four tropical marine habitats
Authors: Staaterman Erica
Published: June 2017

New tools, such as passive acoustic monitoring, can be helpful for measuring levels of biodiversity in habitats that are otherwise difficult to sample. Here, we tested the utility of acoustic measurements in shallow coastal waters by conducting simultaneous bioacoustic and biodiversity surveys in four habitat types in Panama: mangrove, reef, seagrass, and sand. We found that acoustic measurements in the “low band” (<1000 Hz) were positively correlated with cryptic fish species richness. However, our 24-h acoustic recordings revealed a clear toadfish chorus at dusk, which masked other fish sounds and confounded results from newer acoustic indices such as acoustic entropy and acoustic complexity. Band level in the “high band” (3,000-10,000 Hz) did not differ across habitat types and was not significantly correlated to biodiversity measurements. Our study demonstrates that bioacoustic surveys can help scientists to identify certain cryptic, soniferous species, and should be used in tandem with traditional biodiversity surveys. Additional research is needed in the marine environment to validate the utility of the newer acoustic indices.
Soundscape planning: An acoustic niche for anthropogenic sound in the ocean?
Authors: Van Opzeeland Ilse , Boebel Olaf
Published: June 2017

In analogy to landscape planning, the concept of soundscape planning aims to reconcile potentially competing uses of acoustic space by managing the anthropogenic sound sources. We present here a conceptual framework to explore the potential of soundscape planning in reducing (mutual) acoustic interference between hydroacoustic instrumentation and marine mammals. The basis of this framework is formed by the various mechanisms by which acoustic niche formation occurs in species-rich communities that acoustically coexist while maintaining hi-fi soundscapes, i.e., by acoustically partitioning the environment on the basis of time, space, frequency and/or signal form. Hydroacoustic measurements often exhibit certain flexibility in the timing, signal characteristics and even instrument positioning, potentially offering the opportunity to minimize the underwater acoustic imprint. We evaluate how the principle of acoustic niches (i.e., the partitioning of the acoustic space) could contribute to reduce potential (mutual) acoustic interference based on actual acoustic data from various recording locations in polar oceans.
Rapid extraction of ecologically meaningful information from large-scale acoustic recordings
Authors: McKenna Megan F. , Buxton Rachel , Clapp Mary , Meyer Erik
Published: June 2017

Acoustic recordings have the potential to address a suite of important conservation questions, from assessing phenology shifts due to climate change, to examining the impact of anthropogenic noise on wildlife, to monitoring biodiversity at enormous spatio-temporal scales. However, consistent methods are required to extract meaningful information from these large datasets. Here we apply a method of calibrating recordings to standardize acoustic data collected at over 50 unique sites in a diversity of habitats across the continental U.S. using a variety of recording units and parameters. The calibration method results in a coarser data resolution, decreasing storage space and computation time of further analysis. We then apply recently developed acoustic indices to evaluate biodiversity in our recordings. A review of existing acoustic indices and degree of correlation with bioacoustic activity, species richness, functional diversity, landscape attributes, and anthropogenic influence guided our decisions about what indices to implement. Resulting indices were compared with the diversity of birds from observer point counts and from animal vocalizations observed in the recording spectrograms and to anthropogenic sounds observed in the recordings. The results provide important insight on the utility of each index, or group of indices, to investigate dynamics of ecological communities across large scales.
Variation in dawn chorus acoustic complexity across a global latitudinal gradient
Authors: Swider Colin R. , Parks Susan , Lomolino Mark V.
Published: June 2017

The geography of biological sound is a largely unexplored topic that exists at the boundary of ecoacoustics and biogeography. Identification and characterization of patterns of biological sound and soundscape variation across the planet may provide insight into the potential for acoustics as a tool for biodiversity monitoring and conservation. Ecoacoustic indices are audio signal measurements that can be useful for revealing, characterizing, and comparing such soundscape patterns. Some of these indices, such as the Acoustic Complexity Index (ACI), have been shown to correlate with biodiversity and avian vocalization activity in some systems. The goal of this study was to investigate broad-scale trends in the ACI by testing whether the acoustic complexity of dawn chorus soundscapes follows the known latitudinal gradient in avian biodiversity. The ACI was calculated for dawn chorus recordings from 187 sites worldwide, spanning from -45.4° to 68.1° latitude. Acoustic complexity was expected to be highest near the equator and decrease with absolute latitude, tracking the general avian diversity gradient, because higher avian diversity should result in more elaborate dawn chorus soundscapes. However, the ACI did not track the general avian latitudinal diversity gradient. The results and potential explanations for this trend will be discussed.
Temporal and spatial distribution patterns of toothed whales in Massachusetts Bay using passive acoustics from ocean gliders
Authors: Silva Tammy , Mooney T. Aran , Sayigh Laela , Baumgartner Mark F.
Published: June 2017

Basic information on marine mammal habitat use is necessary for informing ecosystem-based management plans and for mitigating human impacts. Massachusetts Bay is an important marine mammal foraging area in the Gulf of Maine and a region of high human activity, but little is known about toothed whale habitat use, particularly during winter months. Passive acoustic monitoring, particularly from autonomous platforms, provides advantages in studying habitat use in unfavorable conditions. The goal of this work is to use acoustic monitoring to investigate temporal and spatial occurrence patterns of toothed whale species in Massachusetts Bay during late fall/early winter using ocean gliders equipped with passive acoustic recorders. Slocum gliders were deployed in western Massachusetts Bay in 2014, 2015, and 2016. Toothed whales were detected on 92 (72%) of 128 deployment days. Detections occurred more often at night. Ongoing work includes acoustic identification of species and assessing relationships between detections and environmental conditions. These data provide the first evidence of a consistent presence of toothed whales in Massachusetts Bay during late fall and winter, and demonstrate the potential for ocean gliders as a tool to detect toothed whales in areas/times that are difficult to survey with traditional visual methods.
LAMLA 2016: Results from the workshop listening for aquatic mammals in Latin America
Authors: Sousa-Lima Renata S. , Buchan Susannah , Andriolo Artur , Dombroski Julia R.
Published: June 2017

The field of bioacoustics and the applications of passive acoustic monitoring (PAM) methods to investigate aquatic mammals have grown worldwide. In Latin America, a number of researchers are using PAM to investigate different species and habitats. However, due to the lack of a proper venue to discuss research findings and priorities, collaboration within the region is scarce. Considering the clear demand for an opportunity for networking and exchange of information at a regional level, we proposed a series of workshops entitled LAMLA—Listening for Aquatic Mammals in Latin America. The aim of LAMLA is to bring together researchers, professionals, and graduate students working in bioacoustics to communicate their research, network and interact, and discuss directions for a coordinated regional bioacoustics network in order to better utilize research resources. The first edition of LAMLA was held in Natal, Brazil, in June, 2016 and the second edition was held in Valparaiso, Chile, during the XI SOLAMAC Reunion in November 2016. Outcomes and results of these two meetings will be presented as well as our goals and expectations for the 2018 meeting. [LAMLA was supported by PAEP CAPES, Office of Naval Research Global, Cetacean Society International, FAPERN, UFRN, UFJF, UNAM, University of Saint Andrews, Universidad de Concepcion, SOLAMAC, and the Acoustical Society of America.]
Mining noise affects Rufous-Collared Sparrow (Zonothichia capensis) vocalizations
Authors: Viana Yasmin , Young Robert J. , Sousa-Lima Renata S. , Duarte Marina H.
Published: June 2017

Mining activity generates noise through explosions, traffic, machinery, alert signals, etc. Noise affects the behavior of many species that depends on acoustic communication. Our objective was to verify if the noise produced by truck traffic affects rufous-collared sparrow vocalizations. Data were collected in an Atlantic forest fragment located close to a mine at the Peti Environmental Station, in Southeast Brazil. Two digital field recorders (SM2—Wildlife Acoustics) were installed 150m from each other and 25 m from a mining road. The SM2 were set to record at 44.1kHz, from 05:00 to 09:00 am during seven days in October 2012. Using Raven pro 1.4, maximum and minimum frequencies, number of notes and duration of the Z. capensis songs were extracted from the recordings one minute before, one after and during the passage of trucks. Trucks noise spectral measurements were also extracted. The species decreased the duration (H = 17.8, gl = 2, p<0.05), the bandwidth (H = 36.28, gl = 2, p<0.05) and the maximum frequency (H = 24.45, gl = 2, p<0.05) and increased the minimum frequency of the calls (H = 25.34, gl = 2, p<0.05) during exposure to truck noise. These results indicate that noise can affect the vocal behavior of the species and reveal the need to address the acoustic impact of mining on animal species.
Brazilian Cerrado nocturnal summer soundscape
Authors: Ferreira Luane S. , Oliveira Eliziane G. , Rocha Luciana H. , Rodrigues Flávio H. , Sousa-Lima Renata S.
Published: June 2017

The Brazilian Cerrado is one of the world’s biodiversity hotspots. Our objective was to characterize its nocturnal soundscape. 12 autonomous recorders (SongMeter2 + , Wildlife Acoustics) were deployed in Canastra National Park (MG/Brazil) and recorded five consecutive nights during the rainy season. Using Arbimon II soundscape builder we identified four frequency bands with higher activity levels. The lower band (0.3-1.3 kHz) is acoustically occupied throughout the night. The second band (2.8-3.2 kHz) is highly active around sunset and almost disappears after 10 PM. The third band (3.8-6.6 kHz) splits into two near 9 PM, with the upper limit disappearing after 3 AM. The highest frequency band (9-16 kHz) is the broadest and occupied in all recordings, being comprised by unidentified background noise. Insects (mainly crickets and cicadas) are present in the three superior bands, anura in the two lower bands, and birds in the second and third near dusk and dawn. Characterizing such protected soundscapes is vital for future monitoring and identification of changes in this important Brazilian preserve.
Effects of noise on avian abundance and productivity at the landscape scale
Authors: DeRuiter Stacy L. , Bingle Amber , Link Matthew , Pontius Michael , Proppe Darren
Published: June 2017

Songbirds, with their reliance on acoustic communication, may be especially sensitive to potential population consequences of anthropogenic noise. Regional studies suggest that many species avoid noisy areas, and in some cases non-avoiding individuals experience reduced fitness. However, multiple studies of a species sometimes produce conflicting results, perhaps due to localized processes that overpower or exacerbate noise effects. Many studies also use abundance as an imperfect proxy for population persistence. To address these issues, we paired large published datasets—from the MAPs (Monitoring Avian Productivity and Survivorship) program and the U.S. National Parks Service noise map—to assess noise levels and bird demographics across the continental United States. We modeled effects of noise on songbird diversity, abundance, productivity, and physical condition (fat score), accounting for temporal and spatial variation. At the continental scale, diversity decreased with increasing noise, but other effects varied by species. For example, least flycatchers become more abundant with increasing noise, and red-breasted nuthatches less abundant. Effects on fat and productivity also varied by species, with abundance trends not consistently matching productivity. Landscape-scale models such as those presented here may facilitate range-wide conservation measures and help identify species or groups that are most at risk.
Spatial analysis of soundscapes of a Paleotropical rainforest
Authors: VanSchaik Jack T. , Gasc Amandine , Bellisario Kristen M. , Pijanowski Bryan C.
Published: June 2017

The world’s biodiversity is drastically decreasing due to human activity. The paleotropical rainforests of Borneo contribute 10% of the world biodiversity but are at risk of destruction due to logging and other human interests. Soundscape Ecology, defined as the composition of sounds in an environment, is a new field that offers potential for biodiversity assessment. Spatial dynamics are an important component of an ecosystem, yet the link between spatial dynamics and soundscapes has not yet been studied. It should be possible to assess disturbance of an ecosystem by analyzing the spatial structure of the soundscape. Particularly, soundscapes in healthy ecosystems should exhibit more spatial autocorrelation than soundscapes in disturbed ecosystems. We calculated Alpha acoustic and Beta acoustic indices for 13 recorders at each site that had identical spatial configurations. We compared the resultant Alpha indices using Moran’s I, Geary’s C and other statistical tests. We compared Beta indices by Mantel Tests and a new technique, the Beta index Semivariogram, a traditional variogram except using means of Beta indices. Spatial statistics on Alpha and Beta indices, and Beta Index Semivariograms reveal more spatial autocorrelation at the undisturbed site. However, Beta Indices detect disturbance better presumably due to their comparative nature.
Sparsified nightly fish chorusing in the Dry Tortugas during elevated background noise levels due to a tropical storm
Authors: Gottesman Benjamin S. , Francomano Dante , Broadhead Taylor , Pijanowski Bryan C.
Published: June 2017

Determining how fish respond to naturally occurring noise disturbances can provide insight into the biological mechanisms underlying the response of fish to anthropogenic noise. Data collected from passive acoustic monitoring in the Dry Tortugas, FL, showed that a tropical storm significantly increased levels of low-frequency noise over a four-day period. The nightly fish chorus occurring at this site, likely from Black Drums (Pogonias cromis), was significantly reduced during this storm event, with fewer than 10% of grunts detected during the storm’s peak as compared to pre- and post-storm levels. We applied Soundscape Control Charts, a new method to quantify the effects of natural and anthropogenic disturbances. Most commonly used in the industrial sector as alarm systems, control charts identify when a system deviates from its normal state. In this study, Soundscape Control Charts quantified the effects of this tropical storm on the communication of fish. This serendipitous dataset suggests that fish communication is negatively impacted by naturally occurring noise disturbances, and is evidence for the need to preserve marine acoustic habitats in order to facilitate animal communication.
Spectrogram contour analysis of vocalizations of the Asian Small-Clawed Otter (Amblonyx cinerea)
Authors: McCoy Haylea G. , Scheifele Peter M.
Published: June 2017

Asian Small-Clawed Otters (Amblonyx cinerea) are small creatures found in many areas of southern and southeastern Asia, as well as Indonesia. They mate for life and communicate with one another using a wide variety of vocalizations from long, drawn out cries, to small yipping noises. The vocalizations of these otters were recorded in the back up area of the Newport Aquarium and Wellington Zoo and analyzed in Spectra Plus to determine the spectrogram contour of each vocalization. The goal of this research was to gather and compile data on the way the Asian Small-Clawed Otter communicates in order to better understand the way these animals live. These data will now be used to perform vocal clustering and classification using a Hidden Markov model, spectral moments, and geometric contour classification (Lofft, 2009; Williamson, 2014).
Influence of fatiguing noise on auditory evoked responses to stimuli of various levels in a beluga whale, Delphinapterus leucas
Authors: Popov Vladimir , Sysueva Evgeniya , Nechaev Dmitry , Supin Alexander
Published: June 2017

The post-exposure effect of fatiguing noise (half-octave band-limited noise centered at 32 kHz) on the evoked responses to test stimuli (rhythmic pip trains with a 45-kHz center frequency) at various levels (from threshold to 60 dB above threshold) was investigated in a beluga whale Delphinapterus leucas. For baseline (pre-exposure) responses, the magnitude-vs-level function featured a segment of steep magnitude dependence on level that was followed by a segment of little dependence (plateau). Post-exposure, the function shifted upward along the level scale. Due to the plateau in the magnitude-vs-level function, post-exposure suppression of responses depended on the stimulus level such that higher levels corresponded to less suppression. The experimental data may be modeled based on the compressive non-linearity of the cochlea. According to the model, post-exposure responses of the cochlea to high-level stimuli are minimally suppressed compared to the pre-exposure responses, despite a substantially increased threshold. [The study was supported by The Russian Foundation for Basic Research (Grant No. 15-04-01068).]
Comparison between sub-ms fast spatio-temporal imaging and electrical recordings from the bat inferior colliculus using a micro-endoscope
Authors: Yashiro Hidetaka , Funabiki Kazuo , Simmons Andrea , Simmons James A. , Riquimaroux Hiroshi
Published: June 2017

Recently, we demonstrated that our micro-endoscopic system enabled acquiring optical image in submillisecond temporal resolution (132 μs/line) by line-scan. The micro-endoscope was fabricated from optical fiber bundle as an endoscope tip and the bundle was coated by gold and enamel. The tip was beveled as cone-shape for minimal invasion and the surrounding edge became electrical-conductive for being used as an electrode. Then, this system can record electrical activities (local field potentials; LFP, and multi-unit activities; MUA) at a sampling rate of 20 kHz and optical responses (calcium response derived from Oregon green BAPTA-1, AM; ΔF/F) simultaneously. We recorded these responses from the inferior colliculus (IC) of two species of bats (Carollia perspicillata and Eptesicus fuscus) to tone bursts (10, 20, 40, 60, and 80 kHz), noise bursts (5-100 kHz), and downward FM sweeps (80-20 and 100-30 kHz). Along the same scanning line, several activated areas (hot spots) were found responding to a single sound stimulus, while different areas were also found to be activated dependent on types of sound stimulus. We analyzed spatio-temporal characteristics at a single recording site and compared calcium response to electrical activities (LFP and MUA). [Work supported by JSPS, MEXT Japan, ONR, Capita Foundation.]
Potential to use passive acoustics to monitor the invasion of the Hudson River by freshwater drum
Authors: Rountree Rodney A. , Juanes Francis
Published: June 2017

We conducted a preliminary passive acoustic survey of the occurrence of freshwater drum in the New York State Canal System (NYSCS). Similar to more well studied marine members of the Sciaenidae, freshwater drum calls are composed of highly variable trains of 1 to 119 knocks/call (mean = 25 knocks/call), a mean knock period of 33 knocks/s, mean peak frequency of 400 Hz, and mean duration of 0.8 s. The occurrence of reproductively active freshwater drum, as evidenced by the presence of chorus calling throughout the canals, suggests that native drum populations from Lake Champlain, Lake Erie, and Lake Ontario likely all contribute to the Hudson River invasive population. We suggest that freshwater drum most likely also invaded the finger lakes through the NYSCS. The invasion of the Hudson River by freshwater drum is significant because the species had previously been geographically excluded from the entire east coast. It is a prolific species with the widest distribution of any native species in the Americas and will likely have a strong impact on the Hudson River ecosystem. We conclude that passive acoustic surveys are a highly effective non-invasive tool to monitor the future spread of freshwater drum in the Hudson River system.
Regional seabed backscatter mapping using multiple frequencies
Authors: Hughes Clarke John E. , Hiroji Anand , Rice Glen , Sacchetti Fabio , Quinlan Vera
Published: June 2017

The frequency dependence of seabed backscatter has previously been assessed at static sites. While dependencies have been identified, the restricted range of seabed types and issues of absolute calibration have limited inferences. Until recently seabed backscatter measurements from underway mapping sonars (sidescans and multibeams) have predominantly been at a single center frequency, dictated by the range versus resolution compromise best suited for the sonar altitude. With improved range performance using FM pulses, the depth range over which a specific frequency is usable have expanded. Taking advantage of that, two national seafloor mapping programs have switched to routine collection of seabed backscatter with wavelength differences of almost an order of magnitude. The NOAA ship Thomas Jefferson and the Irish government vessel Celtic Explorer now are acquiring data at 45 and 300 kHz and 30 and 200 kHz, respectively. Even though absolute calibration remains a concern (particularly for multi-sector systems), the spatial variation of relative backscatter strength clearly provides extra discrimination between seafloors that would not separate using a single frequency. The discrimination occurs both over grazing-angle-normalized scattering strength as well as the variable shape of the angular response curves. For these two programs, data manipulation procedures and preliminary results are presented.
Multibeam sonar water column data processing tools to support coastal ecosystem science
Authors: Church Ian
Published: June 2017

Multibeam sonar water column data are routinely collected by hydrographic survey vessels to observe and validate minimum depth measurements over anthropogenic submerged objects, which may pose a hazard to navigation. A large volume of additional data is collected during this process but mostly goes unused. This project investigates the development of processing tools and algorithms to automate the extraction of oceanographic and ecological features from the water column data files to enhance the usefulness of these datasets. Sample data from a Gulf of Mexico Research Initiative (GoMRI) project is explored where multibeam data is collected simultaneously with a towed profiling high resolution in situ ichthyoplankton imaging system (with CTD, dissolved oxygen, PAR, and chlorophyll-a fluorescence sensors). The objective is to identify and map spatial and temporal variations in biomass throughout the water column by correlating the acoustic data with imagery and sensor output from the towed profiling system. Processing the dataset to isolate and identify objects and signal patterns of interest, which might normally be considered noise, is investigated. The developed tools will aid in biological and physical feature extraction to further enhance the application of multibeam acoustic water column data.
Use of acoustic estimates of euphausiid biomass in trophic dynamics and ecosystem models of the Georges Bank/Gulf of Maine Region from 1999 to 2012
Authors: Jech J. Michael , Lawson Gareth L. , Lowe Michael , Lucey Sean , Fratantoni Paula
Published: June 2017

Euphausiids are a key link between primary production and higher-level predators in the Gulf of Maine, but are not well sampled during standard fisheries surveys. Multifrequency acoustic data may provide useful estimates of euphausiid distribution and biomass, as long as automated classification of acoustic backscatter is reliable and robust. Estimates of euphausiid biomass in the Georges Bank region of the Gulf of Maine were derived from annual acoustic/midwater trawl surveys from 1999 through 2012. Acoustic data were collected continuously with Simrad EK500 and EK60 echo sounders operating at 18, 38, and 120 kHz. Four different methods were used to classify euphausiids from the acoustic data: multifrequency single beam imaging, “dB-differencing” of 120- and 38-kHz volume backscatter, multifrequency z-score, and a multifrequency index. Scattering model predictions of euphausiid target strength and biological metrics were used to scale acoustic data to biomass for each classification method. Biomass estimates were compared among classification methods and to depth-stratified quantitative net samples to evaluate whether the acoustically-derived biomass estimates were commensurate with historical estimates. Biomass estimates were also incorporated in ecosystem models and in calculations of euphausiid consumption by fish and other predators to assess their importance in the ecosystem and their trophic significance.
Assessment of three sonars to evaluate the downstream migration of American Eel in the St. Lawrence River
Authors: Gurshin Christopher W. , Coughlan David J. , Mueller Anna-Maria , Degan Don J. , Jacobson Paul T.
Published: June 2017

This study assessed the feasibility of three sonar technologies to estimate eel abundance, determine distribution, and describe approach behavior to advance strategies for providing safe downstream passage of out-migrating American Eels at hydroelectric facilities on the St. Lawrence River. A Simrad EK60 split-beam echosounder (120 kHz), Sound Metrics ARIS Explorer multibeam sonar (1100/1800 kHz), and Mesotech M3 multi-mode multibeam sonar (500 kHz) were deployed at Iroquois Dam for experimentally testing their capabilities in detecting and identifying known numbers and sizes of live adult eels tethered to surface floats released upstream of the sonar beams and allowed to swim through at known locations and times. In addition, sonars collected data continuously to monitor wild, out-migrating eels during July 15-22 and September 17-19, 2015. Results highlight several challenges in acoustically monitoring eels in a large, fast-moving river with a few orders of magnitude higher abundance of other targets that can lead to a high false positive error rate. The ARIS multibeam sonar, operating with 48 beams, holds the most promise for correctly identifying eels out to 16-20 m in range, but the M3 multibeam sonar has some value for tracking previously identified targets over larger areas.
Gas vesicles: Acoustic biomolecules for ultrasound imaging
Authors: Shapiro Mikhail G.
Published: June 2017

Expanding the capabilities of ultrasound for biological and diagnostic imaging requires the development of contrast agents linked to cellular and molecular processes in vivo. In optical imaging this is commonly accomplished using fluorescent biomolecules such as the green fluorescent protein. Analogously, we recently introduced gas vesicles (GVs) as the first acoustic biomolecules for ultrasound. GVs are physically stable gas-filled protein nanostructures (~250 nm) naturally expressed in aquatic photosynthetic microbes as a means to regulate buoyancy. Purified GVs produce robust ultrasound contrast across a range of frequencies at picomolar concentrations, exhibit nonlinear scattering to enable enhanced detection versus background in vivo, and have species-dependent thresholds for pressure-induced collapse to enable multiplexed imaging. Here, I will present our recent progress on understanding the biophysical and acoustic properties of these biomolecular contrast agents, engineering their mechanics and targeting at the genetic level, developing ultrasound pulse sequences to enhance their detection in vivo and expressing them heterologously as acoustic reporter genes. 1. Shapiro, M.G. et al. Nat. Nanotechnol. 9, 311-316 (2014). 2. Cherin, M. et al. U.M.B. (In press). 3. Lakshmanan, A. et al. ACS Nano 10, 7314-7322 (2016). 4. Maresca, D. et al. In revision. 5. Bourdeau, R.W. et al. Submitted. More information at http://shapirolab.caltech.edu.
In vitro acoustic characterization of echogenic polymersomes with PLA-PEG and PLLA-PEG shells
Authors: Xia Lang , Kumar Krishna , Karandish Fataneh , Mallik Sanku , Sarkar Kausik
Published: June 2017

Echogenic liposomes (ELIPs), lipid bilayer-coated vesicles, have been widely studied as an acoustically triggerable drug delivery agent or an ultrasound contrast agent. Instead of liposomes, polymersomes, amphiphilic vesicles, offer additional stability and chemical flexibility. Here, we report the acoustic behaviors of echogenic polymersomes made of block copolymers PLA-PEG and PLLA-PEG, which are stereo-isomers. Polymersomes were excited with three different frequencies, 2.25 MHz, 5 MHz and 10 MH, and their scattered responses were measured. Both PLA-PEG and PLLA-PEG shell polymersomes produce strong acoustic responses as high as 50 dB in the fundamental component, thus demonstrating their potential as contrast agents. Significant subharmonic as well as second harmonic responses were observed at excitation frequencies of 2.25 MHz and 5 MHz. The gas dissolved in the suspension was found to be essential for the echogenicity of polymersomes.
Acoustic vaporization threshold of lipid coated perfluoropentane droplets
Authors: Aliabouzar Mitra , Kumar Krishna N. , Sarkar Kausik
Published: June 2017

Phase shift droplets that can be vaporized in situ by acoustic stimulation offer a number of advantages over microbubbles as contrast agents due to their higher stability and smaller size distribution. The acoustic vaporization threshold (ADV) of droplets with perfluoropentane (PFP) core has been investigated extensively via optical and acoustical means. However, there are noticeable discrepancies among reported ADV thresholds between the two methods. In this study, we thoroughly discuss the criteria and the experimental methodology of determining the ADV threshold. In addition, we explain the possible reasons for the discrepancies between the optical and acoustical studies of the droplet vaporization. The ADV threshold was measured as a function of the excitation frequency by examining the scattered signal from PFP droplets (400-3000 nm). The threshold increases with frequency¾2 MPa at 2.25 MHz, 2.5 MPa at 5 MHz, and 3 MPa at 10 MHz. The scattered response from droplets was also compared with the scattered response from a microbubble at the corresponding excitation pressure and frequency. We found the ADV threshold to increase with frequency. The ADV threshold values determined here are in agreement with past values obtained using an optical technique.
A model for acoustic vaporization of droplets encapsulated within a nonlinear hyperelastic shell
Authors: Lacour Thomas , Valier-Brasier Tony , Coulouvrat François
Published: June 2017

Nanometric particles with a liquid core arise an increasing interest for medical applications such as contrast imaging and targeted drugs delivery. Unlike conventional ultrasonic contrast agents with a gaseous core (ACU), their dimensions are smaller than the gap endothelium of tumor blood vessels, allowing them to reach tumor tissues. However, because of this liquid core, these particles are poorly compressible and therefore less efficient for imaging than standard ACUs. Their echogenicity may be enhanced by vaporizing the liquid core when applying an ultrasonic field. The investigated particles are made of a liquid core encapsulated within a visco-elastic shell. One assumes the existence of a vapor nucleus at initial time. The shell confines the liquid core and ensures greater stability, but it usually inhibits the spontaneous growth of vapor core. The dynamic of the liquid-vapor interface is described by a generalized Rayleigh-Plesset equation coupled with the heat diffusion equation in the dense phases. The vapor growth induces a significant volume expansion (typically about 100 times) and therefore, the shell is assumed to behave as a hyperelastic soft material to account for large deformation. The complete vaporization is shown to be dependent on the product of the shell shear modulus by its thickness, but also on the nonlinear elastic parameter. Numerical simulations reveal that the bubble dynamic can be distributed into three families, thus enabling to define a threshold and an optimum of acoustical parameters.
Characterization of modular arrays for transpinal ultrasound application
Authors: Qiao Shan , Coussios Constantin , Cleveland Robin
Published: June 2017

Chronic low back pain is one of the most prevalent musculoskeletal conditions worldwide, and is normally caused by the degeneration of intervertebral discs. High intensity focused ultrasound can be used to mechanically fractionate degenerate disc tissue by inertial cavitation. Due to the complexity of the spine structure, delivering sufficient focused acoustic energy to the target zone without damaging surrounding tissue is challenging and further exacerbated by patient-to-patient variability. Here we designed modular arrays, each consisting of 32 elements at 0.5MHz, which can be configured to optimize delivery for a specific patient by the means of time-reversal using the patient geometry derived from CT scans. In this study, the performance of the modular array was measured with a hydrophone and simulated numerically. For a four-module configuration the size of the focus was 4 mm in diameter and 30 mm long with a focal gain of approximately 35 and steering range of the focus was + /-30 mm in azimuth, + /-5mm in elevation, providing the required focusing flexibility and focal pressure for the transpinal application. The numerical simulations agreed well with the measurements suggesting simulations can be used for treatment planning. [Work supported by EPSRC, UK.]