bluuebunny/crossref_metadata_2025 huggingface dataset:
Is metformin a multifunctional medication for inducing ovulation and improving pregnancy outcomes in PCOS?
Authors: Montplaisir Pamela
Published: July 2011

Purpose: To review the pathophysiology of polycystic ovary syndrome (PCOS), discuss the use of metformin—an insulin‐sensitizing agent—as an ovulation induction agent, and investigate whether use of metformin improves ovulation and pregnancy outcomes in females with PCOS.

Data sources: Review of the published literature in on‐line journals, CINAHL database, and MD Consult database using key search terms of metformin, ovulation‐induction, anovulation, polycystic ovary syndrome, insulin resistance, and pregnancy.

Conclusion: Evidence supports the use of metformin as an appropriate first‐line therapy for ovulation induction of infertile PCOS females and also for the treatment of menstrual irregularity. Current data suggest that metformin taken during pregnancy may reduce miscarriage rate, gestational diabetes mellitus complications, and fetal growth problems.

Implications for practice: Metformin, as a single agent, is useful for multiple purposes in the treatment of PCOS: decreasing intestinal glucose uptake and both basal and postprandial glucose levels; inducing ovulation; and improving pregnancy outcomes.
Perspectives for the Treatment of Anemia in Heart Failure: Is There a Role for Vasopressin Antagonists?
Authors: Marques João Silva
Published: July 2011

Anemia is an independent predictor of mortality in congestive heart failure patients. Recent studies have recognized that dilutional anemia is highly prevalent in this population. However, the implications for treatment have not been comprehensively elucidated. In this regard, arginine‐vasopressin antagonists, by increasing aquaresis, may be an attractive treatment option. Nevertheless, only indirect evidence supports the hypothesis that arginine‐vasopressin antagonists may be useful in the treatment of congestive heart failure anemia. Therefore, future clinical research should explore the role of arginine‐vasopressin pathway activation in determining dilutional anemia and, ultimately, assess it as a therapeutic target. Congest Heart Fail. 2012;18:1–3. ©2011 Wiley Periodicals, Inc.
Improving pharmacy counselling skills: an interdisciplinary model of support for students with English as an additional language
Authors: Kokkinn Beverley , Stupans Ieva
Published: July 2011

Objectives

The pilot project, described in this paper, targeted English as an additional language (EAL) students to facilitate their development of patient counselling communication skills.

Methods

An interdisciplinary content-based model was developed drawing on an interactional sociolinguistic framework to map language use valued in pharmacy counselling. Evaluation included analysis of successive self-assessments and surveys of students, surveys of teaching staff and final test results.

Key findings

Evaluation indicated that the interdisciplinary model was highly successful in improving EAL students' competency in pharmacy counselling.

Conclusions

The model may have possible wider application for education in health professional programmes.
Modular Assembly of Volterra Models of Nonlinear Physical Systems
Authors: Motato Eliot , Radcliffe Clark
Published: July 2011

The modular model assembly method (MMAM) is an energy based model distribution and assembly algorithm that distributes and assembles model information through computer networks. Using the MMAM linear and affine physical system, models can be distributed and assembled using dynamic matrices. Though the MMAM procedure can be used for a large class of systems, linear model dynamic matrices cannot be used to represent nonlinear behavior. This work is an extension of the MMAM to assemble nonlinear physical models described through Volterra expansions. Volterra expansions are models representations of smooth nonlinearities. Using the approach proposed here, complex assemblies of nonlinear physical models can be executed recursively while hiding the topology and characteristics of their structural model subassemblies.
Suction-Injection Control of Shear Banding in Non-Isothermal and Exothermic Channel Flow of Johnson-Segalman Liquids
Authors: Chinyoka T.
Published: July 2011

For certain values of the material parameters, certain viscoelastic fluid models allow for a nonmonotonic relationship between the shear stress and shear rate in simple flows. We consider channel flow of such a fluid, the Johnson-Segalman liquid, subjected to exothermic reactions. A numerical algorithm based on the finite difference method is implemented in time and space for the solution process of the highly nonlinear governing equations. The phenomenon of shear banding is observed and explained in terms of the jump discontinuities in shear rates. We demonstrate that for a reacting Johnson-Segalman fluid, the shear banding can be catastrophic as it leads to large temperature buildup within the fluid and hence makes it easily susceptible, say, to thermal runaway. We also demonstrate that the shear banding can be eliminated by making the walls porous and hence allowing for suction and injection. The suction/injection flow is shown to significantly decrease fluid temperatures for the nonmonotonic viscoelastic Johnson-Segalman model but leads to significant temperature increases for the monotonic viscoelastic Oldroyd-B model.
Investigation of motion artifacts associated with fat saturation technique in 3D flash imaging
Authors: Shi Kaining , Zhou Kun , Niu Xueming , Luo Bei , Han Hui , Bao Shanglian , Ma Jingfei
Published: July 2011

Purpose: Fast low‐angle shot (FLASH) imaging is widely used in dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) because it permits fast and accurate T1 measurement in vivo. Suppression of the fat signal is necessary for most FLASH applications; otherwise, fat will appear hyperintense. The fat saturation technique is one popular method to reduce fat images on clinical scanners. However, fat saturation combined with the 3D FLASH sequence in breast DCE‐MRI scans results in heavy ghosting artifacts caused by heartbeat. We used simulation and experimental scans to determine the cause of these artifact‐enhancement phenomena.Methods: We simulated imaging of motion in the x, y, and z directions, with and without fat saturation, to investigate the origin of artifacts. Fourier transform (FT) of the whole field of view was used in the simulation, and we assumed that the uniform phantom was static during one TR. The amplitude of each echo was considered a factor in the FT data. Images were reconstructed using FT data from different phantom positions multiplied by the amplitude factor. Phantom experiments and volunteer studies were implemented to verify the conclusion.Results: Both phantom and volunteer results showed artifacts similar to those in simulation images. We found that FLASH sequence without fat saturation is insensitive to motion. Fat saturation radiofrequency pulses placed before each group of echoes disrupted the steady state of the signal amplitude and produced a low‐pass filter effect that enhanced the motion artifacts.Conclusions: We conclude that the low‐pass filter effect associated with the fat saturation technique is responsible for dramatically increased motion artifacts.
A two‐dimensional deformable phantom for quantitatively verifying deformation algorithms
Authors: Kirby Neil , Chuang Cynthia , Pouliot Jean
Published: July 2011

Purpose: The incorporation of deformable image registration into the treatment planning process is rapidly advancing. For this reason, the methods used to verify the underlying deformation algorithms must evolve equally fast. This manuscript proposes a two‐dimensional deformable phantom, which can objectively verify the accuracy of deformation algorithms, as the next step for improving these techniques.Methods: The phantom represents a single plane of the anatomy for a head and neck patient. Inflation of a balloon catheter inside the phantom simulates tumor growth. CT and camera images of the phantom are acquired before and after its deformation. Nonradiopaque markers reside on the surface of the deformable anatomy and are visible through an acrylic plate, which enables an optical camera to measure their positions; thus, establishing the ground‐truth deformation. This measured deformation is directly compared to the predictions of deformation algorithms, using several similarity metrics. The ratio of the number of points with more than a 3 mm deformation error over the number that are deformed by more than 3 mm is used for an error metric to evaluate algorithm accuracy.Results: An optical method of characterizing deformation has been successfully demonstrated. For the tests of this method, the balloon catheter deforms 32 out of the 54 surface markers by more than 3 mm. Different deformation errors result from the different similarity metrics. The most accurate deformation predictions had an error of 75%.Conclusions: The results presented here demonstrate the utility of the phantom for objectively verifying deformation algorithms and determining which is the most accurate. They also indicate that the phantom would benefit from more electron density heterogeneity. The reduction of the deformable anatomy to a two‐dimensional system allows for the use of nonradiopaque markers, which do not influence deformation algorithms. This is the fundamental advantage of this verification technique.
Round robins in room acoustics.
Authors: Vorländer Michael
Published: July 2011

In 1995, an intercomparison on room acoustics computer simulations was launched, the so-called round robin I. The object of interest was a mid-sized auditorium. That project also included a small measurement project, where sessions of impulse response measurements were carried out with several teams and instrumentation. Since that time, the variations in the results obtained by computer simulations and those obtained by measurements were studied more deeply, and this was the starting point for two more round robins focusing on aspects other room sizes such as a multi-purpose hall and a rather small recording studio. Also, investigations on the uncertainty in ISO 3382 measurements were initiated. In this short presentation the historic round robins I to III are re-visited and plans for a round robins IV focusing on auralization on room acoustics are discussed.
Benchmarks in computational room acoustics.
Authors: Svensson U. Peter
Published: July 2011

A benchmark project called “A Benchmarking Framework for Wave-Based Computational Methods” was run in Japan, 2003–2005, coordinated by Tetsuya Sakuma, University of Tokyo, and with a few European participants. The project defined a number of interior and exterior (scattering) cases, ranging from very simple shapes to more realistic cases. A web site was set up where results, timing data, and methods could be submitted in great detail. A recent benchmark initiative, by Dirk Schroder and Michael Vorländer from RWTH, Aachen, is to create an “open measurement” web site where measurement results, software, etc., can be gathered and openly available. Brief presentations of those benchmark efforts will be given.
Sound propagation at micro-scale in urban areas.
Authors: Kang Jian
Published: July 2011

While large scale noise-mapping techniques have been applied extensively in practice, as required by the EU Directive on environmental noise, they are often not applicable for micro-scale urban areas, such as a street or a square. This talk will discuss a series of simulation techniques as well as related acoustic theories for accurately calculating the sound field for micro-scale urban areas. This includes energy-based image source methods for street canyons and urban squares with geometrically (specularly) reflecting boundaries, image source method considering interference, ray-tracing, radiosity model for diffusely reflecting boundaries, transport theory, equivalent source method, and some other models. Techniques for urban acoustic animation will also be briefly discussed.
Computational techniques for underwater acoustic time-series simulations.
Authors: Siderius Martin
Published: July 2011

In the underwater environment, electromagnetic signals are highly attenuated and therefore acoustic systems are primarily used for remote sensing, communications, and imaging. Underwater acoustic propagation modeling is used to understand performance of these systems and the subject is considered fairly mature. A variety of approaches have been developed to simulate acoustic time-series in underwater environments (i.e., the ocean). Usually the biggest challenge is simply knowing the propagation environment in enough detail for accurate simulations. Setting that aside, there are several other complicating factors that limit the quality of simulations even in known environments. Among these are the irregular boundaries at the sea-surface and seabed boundaries which scatter the acoustic field. Solutions to these scattering problems are often formulated in the frequency domain and time-series formed using Fourier synthesis. However, Doppler effects due to sea-surface motion as well as source and receiver motion add additional modeling challenges particularly for frequency domain approaches. In these cases, ray-based techniques have been used successfully to model acoustic time-series. In this presentation the various approaches to simulating underwater acoustic time-series will be described for static and dynamic environments. Applications of these simulations for predicting reverberation and multipath in the underwater environment will also be presented.
The inclusion of diffraction effects in room acoustical modeling.
Authors: Svensson U. Peter
Published: July 2011

This paper will give a brief overview of some alternatives for including diffraction effects in computational room acoustics. Geometrical acoustics is the basis for most computer modeling methods in room acoustics, and both deterministic and stochastic approaches are used. The image source method and the beam tracing method dominate for the former, and ray tracing for the latter. Deterministic methods are used for sequences of specular reflections, and diffraction effects are straightforward to include in such methods. Paths that involve at least one diffuse reflection are usually handled by ray tracing and recent work has suggested how to implement diffraction in ray tracing. The inclusion of diffraction effects might offer more accurate modeling, most notably for free-hanging reflectors, orchestra pits, balcony edges, etc. The boundary condition issue will be discussed since diffraction solutions that are useful in room acoustics exist only for ideally rigid surfaces. Underlying approximations in some formulations will be mentioned, and computational aspects will be described, including the huge number of diffraction paths that are generated in a room, with a corresponding huge range of amplitudes. Special attention will be given to singularity issues and an attempt at an outlook for the near future will be offered.
Efficient acoustic radiance transfer method with time-dependent reflections.
Authors: Siltanen Samuel , Lokki Tapio , Savioja Lauri
Published: July 2011

Modern desktop computers are equipped with graphics cards that provide massive parallel computation power that was previously available only in supercomputers. On the other hand, there are several room acoustics modeling methods, but only some of them scale well to hundreds or thousands of parallel processors. The scalability of the acoustic radiance transfer method is examined. It is shown that it can almost fully utilize the available computing power. In simple cases, this technique achieves real-time performance. While taking into account the limitations of the energy-based acoustic modeling approach, the presented system can model arbitrary reflections. The reflections are presented as bi-directional reflectance distribution functions, which depend on the incoming and outgoing directions of acoustic energy. It is also possible to add time-dimension to such a reflection model. Some measurements are presented to show that spreading in time dimension occurs at reflections. Most of the previous room acoustics modeling techniques have ignored that phenomenon, but the acoustic radiance transfer technique can be easily modified to take this spreading effect into account.
Efficient simulation of active sonar using concepts from room acoustics and auralization.
Authors: Summers Jason E.
Published: July 2011

Many systems for real-time simulation of active sonar reflect the historical division between propagation and reverberation algorithms. Though sonar returns comprise continua of echoes, systems treat scatterers as discrete targetlike entities or as distributed entities described by scattering strengths associated with regions of the ocean boundaries or volume. This approach limits the development of computational algorithms. In the fields of room acoustics and virtual reality there has been significant research devoted to development of efficient algorithms that enable computational simulation and real-time rendering (auralization) of sound fields resulting from complex scenarios. Such work exploits knowledge of the physical processes and limitations of the human auditory system to enhance the relevant aspects of fidelity while reducing computational load. Similar conditions exist for the simulation of active sonar. This presentation describes how concepts from room acoustics and auralization can be applied toward an active-sonar simulation that is scalable and implicitly incorporates tradeoffs between speed and accuracy. Rather than develop new propagation or reverberation algorithms, gains can be achieved by creating a system that treats all echos within a unified framework and explicitly accounts for properties of source, path, and receiver in order to optimize use of existing algorithms.
Comparison of room-acoustical parameters predicted using different surface-reaction models.
Authors: Yousefzadeh Behrooz , Hodgson Murray
Published: July 2011

This paper presents the development of a beam-tracing model for calculating the transient responses of rooms. The model is wave-based (i.e., includes phase changes due to distance traveled and wall reflections), and can be applied to rooms with extended-reaction surfaces. Room surfaces can be modeled as multiple layers of solid, fluid, and poroelastic materials; their acoustical properties are calculated using a transfer-matrix approach. The beam-tracing model calculates the complex transfer function of a room. Pressure impulse responses are then computed via Fourier transformation, and the room-acoustical parameters derived. Since pressure impulse responses are calculated, the model can also be used for auralization. The model has been applied to different room configurations in order to study the effects of different surface-reaction models on the predicted steady-state characteristics and temporal variations of sound-pressure fields in various room configurations. In particular, the audibility of using different boundary conditions (local versus extended reaction, wave-based versus energy based modeling, and phase changes on reflection) on the room-acoustical parameters has been investigated: In each configuration, room parameters have been calculated using different boundary conditions, and audible variations of the parameters have been studied and explained.
Customized room acoustics simulations using scripting interfaces.
Authors: van der Harten Arthur W.
Published: July 2011

Geometrical computer modeling is commonly used in consulting practice to make predictions of room acoustical quality. A large number of new parameters have been created by academicians and acousticians in recent years—so much so that it has been difficult for room acoustics simulation providers to include them all. This presentation will demonstrate how customized scripted simulations in Rhinoceros (a CAD program), using Pachyderm (an open source geometrical acoustics simulation engine), can allow the use of new parameters, or parameter simulation types, without reliance on software vendors to explicitly release software versions implementing new code.
Mid-basin deep-water low-frequency ambient noise estimation.
Authors: Carey William M. , Evans Richard B.
Published: July 2011

Estimating the increase in noise due to commercial shipping is of interest because of naval operations and its environmental consequences to marine life. Recent low-frequency noise calculations [Evans and Carey, Proceedings of the 9th ICTCA, Univ. Bundeswehr, DE] for the mid-Philippine sea illustrate the major uncertainties due to the basin’s slope reflectivity, the number density, and the source level radiation characteristics of commercial ships. Canonical source level characteristics are based on naval studies on measurements some 3 decades ago. In the early seventies, Ross [J.O.E. 30(2), (2005)] estimated the rate of increase of noise levels based on an empirical relationship between the radiated source level and tonnage to be order 0.5 dB/year based on the commercial ships of that era. Currently there are as many as seven classes of ships with an order of magnitude increase in tonnage, hull size, drafts, and propeller size. A plausible consequence is a radiation characteristic with a different directionality and effective efficiency. Deep ocean calculations are presented illustrating the uncertainties of slope enhancement and shipping noise levels. The current commercial ships are reviewed, qualitative estimates of the radiation characteristics are presented, and ambient noise implications discussed. [Work sponsored by ONR OA.]
Shipping noise signatures.
Authors: Veirs Val , Veirs Scott , Wood Jason
Published: July 2011

Throughout 2010, underwater recordings have been made of each ship passing two separate Haro Strait nodes of the OrcaSound.net hydrophone network. About 20 ships pass each day. Each ship has been identified in real time [automatic identification system (AIS)]. Measurements of received underwater noise levels and AIS variables are recorded as each ship passes the listening stations. Individual ships are observed multiple times moving in either northerly or southerly directions at times separated by a day or two and also by intervals of months. A database has been developed that contains the spectrum level of each ship (bandwidth 96 kHz at one location and 22 kHz at the other) and the source level both in terms of intensity and angular distribution. Ship signatures in terms of frequency quantiles and angular distributions of emissions are quite reproducible. This database can be used to predict limitations on echolocating and vocalizing marine mammals’ active space due to specific ship noise emissions. In particular, predictions of marine mammal noise exposures in specific frequency bands can be made prior to specific vessels’ entry into an area opening the possibility of planning field observations to investigate correlations between behaviors and specific predicted noise exposures.
Measurements of radiated underwater noise from modern merchant ships relevant to noise impacts on marine mammals.
Authors: McKenna Megan F. , Ross Donald , Wiggins Sean M. , Hildebrand John A.
Published: July 2011

There is mounting concern over the effect of ship noise on marine mammals; however, limited empirical data quantifying this noise impede our ability to evaluate impacts. An opportunistic approach for measuring radiated ship noise (20–1000 Hz) was used in this study. Calibrated acoustic data were combined with archived information on seven types of modern merchant ships transiting the coast of southern California. Three metrics for describing ship noise were applied: received sound levels (RLs) during 1 h passages, estimated source levels (SLs), and sound exposure levels (SELs). 1 h passages provided an estimate of the spatial extent of ship noise. At 40 Hz, container ships elevated noise above background up to 7 km forward of the ship and 19 km aft; bulk carriers elevated noise above background up to 5 km at bow and stern aspects. These ship-types had similar broad band estimated SL, 186 dB re 1 μPa at 1 m. The cumulative exposure to ship noise varied by ship type; we presented equations for estimating SELs for specific ship types. In concert, these metrics create a tool for quantifying ship noise within coastal marine environments, and can be used to assess the impact of ship noise on marine mammals. [This work was supported by the U.S. Navy CNO N45 and additional funds from the ONR, the NOAA, and the NSF.]
Using active acoustics to reveal patchiness in the coastal ocean and its ecological consequences for plankton, fish, birds, and marine mammals.
Authors: Benoit-Bird Kelly
Published: July 2011

In the ocean, most resources are heterogeneously distributed and highly dynamic. This patchiness in time and space has significant consequences for population dynamics, trophic interactions, community organization and stability, and the cycling of elements. However, this heterogeneity also presents a significant sampling challenge. A combination of active acoustic tools was used to quantify the relationships between predators and their prey in a variety of marine systems. The results show that patches of prey can have ecosystem impact disproportionate to their biomass. We found that the number and intensity of aggregations at each trophic level rather than the biomass in each step of the food chain involved were the most significant predictors of variation in adjacent trophic levels in the pelagic sub-arctic, temperate, and tropical systems examined. The importance of spatial pattern in ecosystems has long been recognized and its effects on predator-prey pairs has been examined in a number of previous studies; however, patchiness as the dominant force regulating an entire system has not been previously demonstrated, primarily because of the technical challenges of measuring the spatial and temporal scales of biological variability in the ocean.
Active acoustic monitoring systems for detecting, localizing, tracking, and classifying marine mammals and fish.
Authors: Stein Peter J.
Published: July 2011

Detection, localization, tracking, and classification (DLTC) of marine mammals and fish is necessary for a wide range of bioacoustic studies. This includes those related to understanding anthropogenic effects and to the development of methods for mitigating harm. Active acoustic monitoring (AAM) is a robust method for monitoring marine life as it can detect and accurately localize a silent target, enabling full DLTC. With the growth of the offshore renewable energy industry and the need to mitigate harm from pile driving, seismic surveys, and military sonar operations, there is strong interest in developing AAM systems and integrating them with current mitigation techniques. There are a host of significant issues including the standard sonar problems of reverberation and propagation in high-clutter shallow water environments, false alarms, classification, methods of deployment, and cost. Furthermore, AAM systems transmit acoustic energy that has the potential to disturb marine life. Much work lies ahead to develop systems that balance the risks, benefits, performance, and costs. This paper will review the status and issues of AAM systems. This includes a discussion of implemented near-field (imaging) and far-field (tracking) systems, experimental results, and plans for further development, testing, integration, and permitting.
Frequency shifts of echolocation pulses in a cluttered environment: Comparison between Pipistrellus abramus and Miniopterus fuliginosus.
Authors: Takenaga Toshiya , Hiryu Shizuko , Simmons James A. , Riquimaroux Hiroshi , Watanabe Yoshiaki
Published: July 2011

Changes in frequency range (ΔF) of FM echolocation pulses were recorded with an onboard wireless microphone (Telemike) for Pipistrellus abramus and Miniopterus fuliginosus in a cluttered environment created by dense chain-row obstacles. The duration of echo streams (ESD) from the chains reached ∼40 ms when the bats were flying toward the chain-row obstacles. P. abramus emitted pulses in pairs (strobe group) with 20–40 ms interpulse intervals (IPIs), which occasionally created pulse-echo ambiguity (IPI was shorter than ESD). When successive echo streams did not overlap, ΔF within strobe groups was less than 2–3 kHz. When overlap occurred, Δ F increased to 5–6 kHz (F-test, P < 0.001). By shifting frequency range of successive FM pulses, P. abramus appeared to assign echoes to the corresponding pulses and avoid pulse-echo ambiguity. Similar finding was previously reported in Eptesicus fuscus. On the other hand, M. fuliginosus never emitted pulses in a strobe group, and IPIs were always adjusted to be longer than ESDs. Thus, the amount of ΔF was less than 2 kHz, which corresponded to that in P. abramus without pulse-echo ambiguity. These comparative results suggest that echolocation strategy in the cluttered environment is different between two FM bat species. [Work supported by JSPS and ONR.]
Spatial and temporal patch dynamics of mysid swarms using combined stationary and shipboard active acoustics.
Authors: Kaltenberg Amanda M. , Benoit-Bird Kelly J. , Waluk Chad M.
Published: July 2011

Mysid populations form into dense swarms and provide an important prey resource for large predators on the central Oregon coast including resident gray whales and a variety of fish species. The spatial and temporal characteristics of mysid patches were investigated in July and August, 2010 using combined stationary and shipboard active multifrequency acoustics. Mysid patches were analyzed to characterize the dynamics relevant to their availability as prey to larger predators. Concurrent net and video sampling provided validation of mysid species and size-class identification. Dense patches containing distinct size classes and mixed-size assemblages were observed from shipboard spatial surveys inshore of the 15 m isobath, where gray whales were actively foraging throughout the study. Bottom-mounted acoustic moorings revealed a distinct diel pattern of swarm density and vertical distribution, as mysid patches often separated into layers during night while reforming very near bottom during the day. This study demonstrates the usefulness of combining information from stationary and moving platforms of active acoustic methods while providing important information on the patch characteristics of a critical prey group.
The Northwest Association of Networked Ocean Observing Systems and opportunities for acoustical applications.
Authors: Newton Jan , Alford Matthew , Mickett John , Payne John , Stahr Fritz
Published: July 2011

NANOOS, the Pacific Northwest Regional Association of the U.S. Integrated Ocean Observing System (IOOS), aims to provide coastal ocean observations improving understanding and enabling decisions to improve safety, enhance the economy, and protect the environment. Biological aspects of ocean observing lag behind physical because of the difficulty of observing animal behavior beneath the surface; yet information about the behavior and survival of marine species in the ocean is identified as a critical need for fisheries management and marine spatial planning. Acoustics are poised to contribute to this need; however, limitations of acoustic arrays must be addressed. NANOOS recognizes opportunities for acoustical applications and has begun exploring these. NANOOS and POST deployed an acoustic receiver on a seaglider to test feasibility of using gliders to extend the scope of acoustic tracking arrays into deeper water and as a rapid deployment technology to test fixed arrays and investigate oceanographic features. During a 3-month test deployment, July–October 2010, a receiver mounted on the seaglider worked flawlessly and made two detections: one from a salmon and one from a Humboldt squid. NANOOS has proposed to develop methods for integrating instruments for tracking migrations of fish and marine mammals into ocean observing networks.
Acoustic challenges in aquatic ecosystem assessment.
Authors: Horne John K. , Schmid Charles E. , McClure Robert , Siderius Martin
Published: July 2011

In an effort to increase communication and collaboration between members of the Acoustical Society of America and the American Fisheries Society, a joint workshop focusing on the integration of biological and physical elements in ecosystem research, current policy and regulations, and applications of acoustic technologies developed field use will be held Thursday and Friday during the conference. Topics of interest in the workshop include the following: ecosystem based resource management, cabled observatories, monitoring renewable energy sites, acoustic species discrimination, statistical analysis for fisheries assessment, progress in fish tagging, acoustical models for fisheries assessment habitat inventory, detecting, and monitoring episodic events: natural and anthropogenic, active and passive assessment, and quantitative assessments in noisy environments. Ocean observatories is an explicit topic of interest in the workshop, but it can serve as an integrating theme that potentially expands the scope and capabilities of aquatic ecosystem assessment.
Acoustic monitoring of beluga whales (Delphinapterus leucas) in Cook Inlet, Alaska.
Authors: Castellote Manuel , Small Robert , Atkinson Shannon , Lammers Marc O. , Jenniges Justin , Rosinski Anne , Garner Christopher , Moore Sue , Au Whitlow L. L.
Published: July 2011

Cook Inlet belugas (CIBs) are listed as endangered under the U.S. Endangered Species Act. Their current seasonal distribution is essentially unknown and the factors impeding their recovery over the past decade are unknown, yet could include anthropogenic activities that impact their acoustic ecology, including coastal development, oil and gas exploration, shipping and military activities.  Beginning in 2008, a cooperative research project has acquired new information on background noise levels and the seasonal presence of CIBs throughout Cook Inlet using passive acoustic monitoring. Mooring packages containing ecological acoustic recorders (EARs) and echolocation loggers (C-PODs) have been deployed at ten sites to continuously monitor the presence of CIBs. Cook Inlet is a challenging environment for acoustic monitoring because of extreme tides and currents, sediment dynamics, debris from rivers and seasonal ice that characterize the area.  Noise from both natural and anthropogenic sources often make beluga call detection challenging. However, the effort to date has met with success and is providing valuable insights into beluga movement patterns and the acoustic environment they face. This methodology also allows monitoring other odontocetes such as killer whales (Orcinus orca), detected mostly in the lower inlet, and harbor porpoise (Phocoena phocoena) detected throughout the inlet.
Using acoustic cue statistics in matrix population models to study short-term and long-term marine mammal population dynamics in the northern Gulf of Mexico.
Authors: Sidorovskaia Natalia , Ackleh Azmy , Pal Nabendu , Ioup Juliette W. , Ioup George E. , Tiemann Christopher O.
Published: July 2011

Acoustics is emerging as a viable tool for determining population trends of deep diving marine mammals in addition to conventional transect-line visual observations which are often limited by weather conditions, short-time surface presence, costs, etc. In September 2010, following the recent oil spill in the Gulf of Mexico, the Littoral Acoustic Demonstration Center (LADC) conducted a passive acoustic experiment as part of a study of short-term and long-term effects of the oil spill on the resident population of marine mammals. Environmental Acoustic Recording System (EARS) buoys were redeployed in three locations: 9 mi, 23 mi, and 50 mi away from the Deepwater Horizon-oil spill site. LADC previously collected data at these locations in 2001, 2002, 2007. The pre-spill data are used as a baseline for estimating long-term population trends. Densities of acoustic phonations of sperm whales, beaked whales, and dolphins are extracted from collected data and used for point estimates of the resident population density. LADC extensive work on an individual acoustic identification is reviewed in the context of mark-recapture statistics used in matrix population models. Trends in population density after the spill are presented and discussed. [Research is supported by ONR and NSF. Ship services donated by Greenpeace.]
Next generation science, engineering, and education in the ocean basins: sensor-robotic networks communicating near the speed of light.
Authors: Delaney John R. , Daly Kendra L. , Kelley Deborah S. , Luther Douglas L.
Published: July 2011

Complex processes driven by solar and internal geothermal energy within the ocean basins constitute the “flywheel” of our planetary life-support system. Ocean-atmosphere dynamics determine the weather patterns and short-term climatic variations that continually impact the continents. New approaches to understanding the complexity and uncertainties of this “oceanic modulator” arise from the rapid implementation of submarine cabled networks providing unprecedented electrical power and communications bandwidth to thousands of sophisticated robot-sensor systems distributed throughout a full ocean environment. Empowered by cabled systems, oceanographers will benefit from emergent technologies driven by major investment from communities external to ocean sciences. Developments include robotics, biotechnology, cloud computing, in situ chemical and genomic sensors, digital imaging, nanotechnology, new visualization technologies, computational modeling, seismic tomography, passive and active acoustic sensors, and the internet. More powerful than any one of these emerging technologies is the convergence of the ensemble in pursuit of ocean science. As rapidly evolving capabilities are integrated into sophisticated, remote, interactive operations, a pervasive human tele-presence throughout our once ‘inaccessible’ global ocean will be realized. Such capabilities are required to meet environmental-societal challenges in the coming decades, which can only be addressed through optimally informed national and international collaborations.
Acoustic monitoring of marine life with a fiber-optic, ocean-observing network.
Authors: Southall Brandon L. , Clark Christopher , Daley Kendra , Moore Sue , Payne John , Payne Roger , Stafford Kate , Stoermer Mark , Tyack Peter , Wilcock William , Delaney John
Published: July 2011

The application of fiber-optic, high-bandwidth transmission technology is revolutionizing ocean observing by enabling the synoptic acquisition of high-density data streams, including acoustic measurements. A multi-disciplinary collaboration of geophysicists, acousticians, and biologists is developing acoustic observation systems within a cabled observing network being deployed off Washington and Oregon for the next 25 years. This system will include various sensors, including echosounders to detect zooplankton and fish, broadband hydrophone clusters for detecting various marine animals in biologically relevant areas, and low-frequency line arrays to locate and track vocalizing baleen whales across the Juan de Fuca plate region. These capabilities will enable monitoring of acoustically active individuals engaged in feeding, migrating, socializing, and other aspects of natural history. In combination with other tools (e.g., animal tags and remote sensors), these rich data streams will be integrated to monitor ecosystems and the physical and biological forces driving their composition. The use of this powerful cabled monitoring network to synoptically observe and acoustically monitor marine life provides an unprecedented opportunity to systematically study this important area and the influences of climate variability and human activities on marine life. It also demonstrates the immense benefits for understanding the ocean with emerging technologies and cross-disciplinary collaboration.
Multibeam sonar observations of hydrothermal flows at the Main Endeavour Field.
Authors: Rona Peter A. , Benis Karen G. , Jones Christopher D. , Jackson Darrell R.
Published: July 2011

The Cabled Observatory Vent Imaging Sonar has been deployed at the Main Endeavour Node of the Canadian Neptune cabled observatory and has acquired data on plume and diffuse hydrothermal flows. Based on the Reson 7125 multibeam sonar and operating at 200 and 400 kHz, two-dimensional and three-dimensional time series are produced using plume backscattering, Doppler shift, and acoustic scintillation. Hydrothermal plumes and diffuse flow are important as agents of transfer of heat, chemicals, and biological material from the mantle and crust into the ocean in quantitatively significant amounts. High-frequency sonar measurements offer the possibility of inversion to obtain fluxes of central importance in these processes. Long-term time series, obtainable in cabled systems, allow observations of hydrothermal response to tidal, tectonic, and volcanic forcing. Examples will be given of plume bending due to currents, determination of entrainment of ambient water, time variation of diffuse flows, and Doppler determination of volume flux. [Work supported by NSF Grants Nos. OCE-0824612 and OCE-0825088.]
Design of dual mode high intensity focused ultrasound transducers for prostate therapy.
Authors: Jean-Yves Chapelon , Guillaume Bouchoux , Cyril Lafon
Published: July 2011

In HIFU applications, either MRI or ultrasound is used for treatment guidance and monitoring. When ultrasound imaging is used, a separate imaging transducer can be confocally aligned with the therapy probe itself. Yet, in endocavitary applications, such as transrectal prostate HIFU treatment, there are significant constraints on the size and geometry of the final probe, and the integratation of the imaging transducer with the therapy probe is a significant challenge. One solution to this problem is to use the same transducer elements for both imaging and therapy. Dual-mode transducers meet the specifications for therapy and imaging by taking into account the constraints linked to the features of the therapy transducer different from those of the imaging probe. This presentation discusses the results of simulations undertaken to determine an optimal geometry for a dual-mode probe that can be used both for thermal ablation of the prostate as well as for obtaining ultrasound images of sufficient quality for treatment guidance. A new dual-mode design is presented that allows for a smaller overall device than with separate imaging/therapy transducer designs, and Field II simulated images of prostate show that image quality equivalent to or better than those obtained with dedicated imaging probes can be obtained. [This research is supported in France by ANR Program Tecsan 2010.]
High speed imaging of shockwave-induced dynamics of cavitation bubbles and vessel wall.
Authors: Chen Hong , Perez Camilo , Brayman Andrew A. , Matula Thomas J.
Published: July 2011

High speed optical imaging under a microscope (high speed photomicrography) was used to observe shockwave-induced bubble dynamics and bubble-induced vascular dynamics. Ultrasound contrast agent microbubbles, serving as cavitation nuclei, were injected into the vessels of ex vivo rat mesentery. The bubbles were then insonated by focused shock wave pulses with peak positive pressures of 42 MPa and peak negative pressures of 10 MPa, generated by an electromagnetic shockwave source (Storz Duolith). The recorded images were analyzed to obtain bubble radius-time curves, vessel wall displacement, as well as their corresponding velocities. In general, bubble dynamics induces vessel distention (outward displacement of vessel wall) and invagination (displacement of vessel wall into the lumen). Comparisons of shockwave-induced dynamics with HIFU-induced dynamics will also be presented. [Work supported by NIH EB000350 and AR053652.]
Interface capturing simulations of acoustically driven bubble dynamics in and near tissue.
Authors: Freund Jonathan , Tiwari Arpit , Shukla Ratnesh , Pantano Carlos
Published: July 2011

Tissue injury during therapeutic ultrasound or lithotripsy is thought, in cases, to be due to the action of cavitation bubbles. Assessing this and mitigating it is challenging since bubble dynamics in the complex confinement of tissues or in small blood vessels are challenging to predict. Simulations tools require specialized algorithms to simultaneously represent strong acoustic waves and shocks, topologically complex liquid-vapor phase boundaries, and the complex viscoelastic material dynamics of tissue. We discuss advances in a simulation tool for such situations. A single-mesh Eulerian solver is used to solve the governing equations. Special sharpening terms maintain the liquid-vapor interface in face of the finite numerical dissipation included in the scheme to accurately capture shocks. A recent enhancement to this formulation has significantly improved this interface capturing procedure, which is demonstrated for simulation of the Rayleigh collapse of a bubble. The solver also transports elastic stresses and can thus be used to assess the effects of elastic properties on bubble dynamics. A shock-induced bubble collapse adjacent to a model elastic tissue is used to demonstrate this and draw some conclusions regarding the injury suppressing role that tissue elasticity might play.
Prototype for expulsion of kidney stones with focused ultrasound.
Authors: Shah Anup , Harper Jonathan D. , Cunitz Bryan W. , Kucewicz John C. , Wang Yak-Nam , Simon Julianna C. , Lu Wei , Kaczkowski Peter J. , Bailey Michael R.
Published: July 2011

Residual fragments remain in over 50% of treatments for lower pole kidney stones. A second-generation device based on a diagnostic ultrasound system and scanhead has been developed with a unique algorithm for stone detection and the capability to focus ultrasound to expel residual fragments. Focused ultrasound was applied to a bead on string in a water tank as well as to human stones (<5 mm) implanted in the lower pole of a live porcine model via retrograde ureteroscopy. Histological samples were collected and scored in a blinded fashion for therapeutic exposures and for super-therapeutic levels. The in-vitro bead was visually observed to move under focused ultrasound. Even with progressive manual displacement of the bead, the system continuously tracked and caused bead movement in real time. In the live porcine model, stones were expelled from the lower pole to the ureteropelvic junction in seconds to minutes using pulses at a duty factor of 0.02 and 8 W total acoustic power. Injury was observed no more frequently than in controls. Occurrence of injury rose slightly above control at a duty factor of 0.02 and 80 W and at a duty factor of 1 and 8 W. [Work supported by NIH DK48331, NIH DK086371, and NSBRI through NASA NCC 9-58.]
Assessing the effects of respiratory motion on stone comminution in vitro.
Authors: Smith Nathan , Simmons W. Neal , Zhong Pei
Published: July 2011

The effects of respiratory motion on stone comminution produced by an electromagnetic (EM) shock wave lithotripter were evaluated in vitro. Individual spherical BegoStone phantoms (D = 10 mm) were placed in a flat-base tube holder and treated at various radial distances in the lithotripter focal plane. To assess the effects of respiratory motion on stone comminution, the holder was set into translational motions in another series of experiments with various excursion distances (1.5–3.0 cm), breath rates (12–24 bpm), and drift factors for motion randomization. Stone comminution tests were performed using either a newly designed acoustic lens with a wide focal width and a low peak pressure or the original lens under equivalent acoustic energies. The results shows that the new lens produces statistically higher stone comminution (p < 0.01) than the original lens. Moreover, stone comminution at various radial distances will be compared, together with cavitation potential calculated by the Gilmore model based on the pressure waveforms measured by an FOPH.