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Sample records for active sonar target

  1. Waveguide invariant active sonar target detection and depth classification in shallow water

    NASA Astrophysics Data System (ADS)

    Goldhahn, Ryan A.

    Reverberation and clutter are two of the principle obstacles to active sonar target detection in shallow water. Diffuse seabed backscatter can obscure low energy target returns, while clutter discretes, specific features of the sea floor, produce temporally compact returns which may be mistaken for targets of interest. Detecting weak targets in the presence of reverberation and discriminating water column targets from bottom clutter are thus critical to good performance in active sonar. Both problems are addressed in this thesis using the time-frequency interference pattern described by a constant known as the waveguide invariant which summarizes in a scalar parameter the dispersive properties of the ocean environment. Conventional active sonar detection involves constant false alarm rate (CFAR) normalization of the reverberation return which does not account for the frequency-selective fading in a wideband pulse caused by multipath propagation. An alternative to conventional reverberation estimation is presented, motivated by striations observed in time-frequency analysis of active sonar data. A mathematical model for these reverberation striations is derived using waveguide invariant theory. This model is then used to motivate waveguide invariant reverberation estimation which involves averaging the time-frequency spectrum along these striations. An evaluation of this reverberation estimate using real Mediterranean data is given and its use in a generalized likelihood ratio test (GLRT) based CFAR detector is demonstrated. CFAR detection using waveguide invariant reverberation estimates is shown to out-perform conventional cell-averaged and frequency-invariant CFAR detection methods in shallow water environments producing strong reverberation returns which exhibit the described striations. Results are presented on simulated and real Mediterranean data from the SCARAB98 experiment. The ability to discriminate between water column targets and clutter discretes is

  2. A waveguide invariant adaptive matched filter for active sonar target depth classification.

    PubMed

    Goldhahn, Ryan; Hickman, Granger; Krolik, Jeffrey

    2011-04-01

    This paper addresses depth discrimination of a water column target from bottom clutter discretes in wideband active sonar. To facilitate classification, the waveguide invariant property is used to derive multiple snapshots by uniformly sub-sampling the short-time Fourier transform (STFT) coefficients of a single ping of wideband active sonar data. The sub-sampled target snapshots are used to define a waveguide invariant spectral density matrix (WI-SDM), which allows the application of adaptive matched-filtering based approaches for target depth classification. Depth classification is achieved using a waveguide invariant minimum variance filter (WI-MVF) which matches the observed WI-SDM to depth-dependent signal replica vectors generated from a normal mode model. Robustness to environmental mismatch is achieved by adding environmental perturbation constraints (EPC) derived from signal covariance matrices averaged over the uncertain channel parameters. Simulation and real data results from the SCARAB98 and CLUTTER09 experiments in the Mediterranean Sea are presented to illustrate the approach. Receiver operating characteristics (ROC) for robust waveguide invariant depth classification approaches are presented which illustrate performance under uncertain environmental conditions. PMID:21476638

  3. A waveguide invariant adaptive matched filter for active sonar target depth classification.

    PubMed

    Goldhahn, Ryan; Hickman, Granger; Krolik, Jeffrey

    2011-04-01

    This paper addresses depth discrimination of a water column target from bottom clutter discretes in wideband active sonar. To facilitate classification, the waveguide invariant property is used to derive multiple snapshots by uniformly sub-sampling the short-time Fourier transform (STFT) coefficients of a single ping of wideband active sonar data. The sub-sampled target snapshots are used to define a waveguide invariant spectral density matrix (WI-SDM), which allows the application of adaptive matched-filtering based approaches for target depth classification. Depth classification is achieved using a waveguide invariant minimum variance filter (WI-MVF) which matches the observed WI-SDM to depth-dependent signal replica vectors generated from a normal mode model. Robustness to environmental mismatch is achieved by adding environmental perturbation constraints (EPC) derived from signal covariance matrices averaged over the uncertain channel parameters. Simulation and real data results from the SCARAB98 and CLUTTER09 experiments in the Mediterranean Sea are presented to illustrate the approach. Receiver operating characteristics (ROC) for robust waveguide invariant depth classification approaches are presented which illustrate performance under uncertain environmental conditions.

  4. Target detection from dual disparate sonar platforms using canonical correlations

    NASA Astrophysics Data System (ADS)

    Azimi-Sadjdadi, Mahmood R.; Tucker, J. Derek

    2008-04-01

    In this paper a new coherence-based feature extraction method for sonar imagery generated from two disparate sonar systems is developed. Canonical correlation analysis (CCA) is employed to identify coherent information from co-registered regions of interest (ROI's) that contain target activities, while at the same time extract useful coherent features from both images. The extracted features can be used for simultaneous detection and classification of target and non-target objects in the sonar images. In this study, a side-scan sonar that provides high resolution images with good target definition and a broadband sonar that generates low resolution images, but with reduced background clutter. The optimum Neyman-Pearson detector will be presented and then extended to the dual sensor platform scenarios. Test results of the proposed methods on a dual sonar imagery data set provided by the Naval Surface Warfare Center (NSWC) Panama City, FL will be presented. This database contains co-registered pair of images over the same target field with varying degree of detection difficulty and bottom clutter. The effectiveness of CCA as the optimum detection tool is demonstrated in terms of probability of detection and false alarm rate.

  5. Enhanced multistatic active sonar signal processing.

    PubMed

    Zhao, Kexin; Liang, Junli; Karlsson, Johan; Li, Jian

    2013-07-01

    Multistatic active sonar systems involve the transmission and reception of multiple probing sequences and can achieve significantly enhanced performance of target detection and localization through exploiting spatial diversity. This paper mainly focuses on two signal processing aspects of such systems, namely, enhanced range-Doppler imaging and improved target parameter estimation. The main contributions of this paper are (1) a hybrid dense-sparse method is proposed to generate range-Doppler images with both low sidelobe levels and high accuracy; (2) a generalized K-Means clustering (GKC) method for target association is developed to associate the range measurements from different transmitter-receiver pairs, which is actually a range fitting procedure; (3) the extended invariance principle-based weighted least-squares method is developed for accurate target position and velocity estimation. The effectiveness of the proposed multistatic active sonar signal processing techniques is verified using numerical examples.

  6. Demonstration of the invariance principle for active sonar.

    PubMed

    Quijano, Jorge E; Zurk, Lisa M; Rouseff, Daniel

    2008-03-01

    Active sonar systems can provide good target detection potential but are limited in shallow water environments by the high level of reverberation produced by the interaction between the acoustic signal and the ocean bottom. The nature of the reverberation is highly variable and depends critically on the ocean and seabed properties, which are typically poorly known. This has motivated interest in techniques that are invariant to the environment. In passive sonar, a scalar parameter termed the waveguide invariant, has been introduced to describe the slope of striations observed in lofargrams. In this work, an invariant for active sonar is introduced. This active invariant is shown to be present in the time-frequency structure observed in sonar data from the Malta Plateau, and the structure agrees with results produced from normal mode simulations. The application of this feature in active tracking algorithms is discussed.

  7. Timing matters: sonar call groups facilitate target localization in bats

    PubMed Central

    Kothari, Ninad B.; Wohlgemuth, Melville J.; Hulgard, Katrine; Surlykke, Annemarie; Moss, Cynthia F.

    2014-01-01

    To successfully negotiate a cluttered environment, an echolocating bat must control the timing of motor behaviors in response to dynamic sensory information. Here we detail the big brown bat's adaptive temporal control over sonar call production for tracking prey, moving predictably or unpredictably, under different experimental conditions. We studied the adaptive control of vocal-motor behaviors in free-flying big brown bats, Eptesicus fuscus, as they captured tethered and free-flying insects, in open and cluttered environments. We also studied adaptive sonar behavior in bats trained to track moving targets from a resting position. In each of these experiments, bats adjusted the features of their calls to separate target and clutter. Under many task conditions, flying bats produced prominent sonar sound groups identified as clusters of echolocation pulses with relatively stable intervals, surrounded by longer pulse intervals. In experiments where bats tracked approaching targets from a resting position, bats also produced sonar sound groups, and the prevalence of these sonar sound groups increased when motion of the target was unpredictable. We hypothesize that sonar sound groups produced during flight, and the sonar call doublets produced by a bat tracking a target from a resting position, help the animal resolve dynamic target location and represent the echo scene in greater detail. Collectively, our data reveal adaptive temporal control over sonar call production that allows the bat to negotiate a complex and dynamic environment. PMID:24860509

  8. Timing matters: sonar call groups facilitate target localization in bats.

    PubMed

    Kothari, Ninad B; Wohlgemuth, Melville J; Hulgard, Katrine; Surlykke, Annemarie; Moss, Cynthia F

    2014-01-01

    To successfully negotiate a cluttered environment, an echolocating bat must control the timing of motor behaviors in response to dynamic sensory information. Here we detail the big brown bat's adaptive temporal control over sonar call production for tracking prey, moving predictably or unpredictably, under different experimental conditions. We studied the adaptive control of vocal-motor behaviors in free-flying big brown bats, Eptesicus fuscus, as they captured tethered and free-flying insects, in open and cluttered environments. We also studied adaptive sonar behavior in bats trained to track moving targets from a resting position. In each of these experiments, bats adjusted the features of their calls to separate target and clutter. Under many task conditions, flying bats produced prominent sonar sound groups identified as clusters of echolocation pulses with relatively stable intervals, surrounded by longer pulse intervals. In experiments where bats tracked approaching targets from a resting position, bats also produced sonar sound groups, and the prevalence of these sonar sound groups increased when motion of the target was unpredictable. We hypothesize that sonar sound groups produced during flight, and the sonar call doublets produced by a bat tracking a target from a resting position, help the animal resolve dynamic target location and represent the echo scene in greater detail. Collectively, our data reveal adaptive temporal control over sonar call production that allows the bat to negotiate a complex and dynamic environment.

  9. Trading detection for resolution in active sonar receivers.

    PubMed

    Sharma, Nabin S; Buck, John R; Simmons, James A

    2011-09-01

    This paper proposes an active sonar receivers that offers a smooth trade-off between detection and resolution. A matched filter is the optimal detector of known signals in white Gaussian noise but may fail to resolve the targets if the time separation of targets is less than the mainlobe width of the autocorrelation function of the transmitted signal. An inverse filter achieves optimal resolution performance for multiple targets in the absence of noise, but amplifies the noise outside the signal bandwidth in a manner that makes it impractical in many realistic scenarios. The proposed active sonar receiver, the variable resolution and detection receiver (VRDR) combines the matched and inverse filter properties to achieve a smooth trade-off between detection and resolution. Simulated receiver operating characteristics demonstrate that for a range of dipole sonar targets, the performance of the VRDR is superior to the matched and inverse filter, as well as another previously proposed bandlimited inverse filter.

  10. Sonar target enhancement by shrinkage of incoherent wavelet coefficients.

    PubMed

    Hunter, Alan J; van Vossen, Robbert

    2014-01-01

    Background reverberation can obscure useful features of the target echo response in broadband low-frequency sonar images, adversely affecting detection and classification performance. This paper describes a resolution and phase-preserving means of separating the target response from the background reverberation noise using a coherence-based wavelet shrinkage method proposed recently for de-noising magnetic resonance images. The algorithm weights the image wavelet coefficients in proportion to their coherence between different looks under the assumption that the target response is more coherent than the background. The algorithm is demonstrated successfully on experimental synthetic aperture sonar data from a broadband low-frequency sonar developed for buried object detection.

  11. MHT tracking for crossing sonar targets

    NASA Astrophysics Data System (ADS)

    Willett, Peter; Luginbuhl, Tod; Giannopoulos, Evangelos

    2007-09-01

    Sometimes radar targets cross and become unresolved; this is a concern, but with a reasonable track depth and an appropriate merged-measurement model the concern is considerably mitigated. Sonar targets, however, can become merged (in the same beam) for considerably longer, particularly with bearing-only measurements. In such cases the crossing times can be 100 scans long, and no reasonable depth exists for an multi-frame tracker that can "see" both ends of the merged period. Further, there is a demonstrable tendency for estimated targets to repel each other as they are being tracked. In this paper we explore the hypothesis-oriented multi-hypothesis tracker (HO-MHT), an MHT approach that uses the new "rollout" optimization insight and the to give an appropriate and cost-effective means to rank hypotheses, and also the PMHT tracker that operates on batches of scans with linear computational complexity in most quantities. We show results in terms of estimation error (RMSE), consistency (NEES) and computational effort in both linear and beam-space tracking scenarios.

  12. Sonar target enhancement by shrinkage of incoherent wavelet coefficients.

    PubMed

    Hunter, Alan J; van Vossen, Robbert

    2014-01-01

    Background reverberation can obscure useful features of the target echo response in broadband low-frequency sonar images, adversely affecting detection and classification performance. This paper describes a resolution and phase-preserving means of separating the target response from the background reverberation noise using a coherence-based wavelet shrinkage method proposed recently for de-noising magnetic resonance images. The algorithm weights the image wavelet coefficients in proportion to their coherence between different looks under the assumption that the target response is more coherent than the background. The algorithm is demonstrated successfully on experimental synthetic aperture sonar data from a broadband low-frequency sonar developed for buried object detection. PMID:24437766

  13. Probing waveforms and adaptive receivers for active sonar.

    PubMed

    Ling, Jun; Li, Jian; Stoica, Petre; Datum, Michael

    2011-06-01

    Active sonar systems involve the transmission and reception of one or more probing sequences, which provide a basis for extraction of target information in a region of interest. The probing sequences at the transmitter and signal processing at the receiver play crucial roles in the overall system performance. In this paper, CAN (cyclic algorithm-new) is employed to synthesize probing sequences with good aperiodic autocorrelation properties. The performance of the CAN sequences will be compared with those of pseudo random noise and random phase sequences. Two adaptive receiver designs, namely the iterative adaptive approach (IAA) and the sparse learning via iterative minimization (SLIM) method, will also be considered. IAA and SLIM will be compared with the conventional matched filter method. The performances of the algorithms will be illustrated via numerical examples, which show that CAN, IAA, and SLIM can contribute to the overall performance improvement of the active sonar systems.

  14. Neural networks for improved target differentiation and localization with sonar.

    PubMed

    Ayrulu, B; Barshan, B

    2001-04-01

    This study investigates the processing of sonar signals using neural networks for robust differentiation of commonly encountered features in indoor robot environments. Differentiation of such features is of interest for intelligent systems in a variety of applications. Different representations of amplitude and time-of-flight measurement patterns acquired from a real sonar system are processed. In most cases, best results are obtained with the low-frequency component of the discrete wavelet transform of these patterns. Modular and non-modular neural network structures trained with the back-propagation and generating-shrinking algorithms are used to incorporate learning in the identification of parameter relations for target primitives. Networks trained with the generating-shrinking algorithm demonstrate better generalization and interpolation capability and faster convergence rate. Neural networks can differentiate more targets employing only a single sensor node, with a higher correct differentiation percentage (99%) than achieved with previously reported methods (61-90%) employing multiple sensor nodes. A sensor node is a pair of transducers with fixed separation, that can rotate and scan the target to collect data. Had the number of sensing nodes been reduced in the other methods, their performance would have been even worse. The success of the neural network approach shows that the sonar signals do contain sufficient information to differentiate all target types, but the previously reported methods are unable to resolve this identifying information. This work can find application in areas where recognition of patterns hidden in sonar signals is required. Some examples are system control based on acoustic signal detection and identification, map building, navigation, obstacle avoidance, and target-tracking applications for mobile robots and other intelligent systems.

  15. Examining the robustness of automated aural classification of active sonar echoes.

    PubMed

    Murphy, Stefan M; Hines, Paul C

    2014-02-01

    Active sonar systems are used to detect underwater man-made objects of interest (targets) that are too quiet to be reliably detected with passive sonar. Performance of active sonar can be degraded by false alarms caused by echoes returned from geological seabed structures (clutter) in shallow regions. To reduce false alarms, a method of distinguishing target echoes from clutter echoes is required. Research has demonstrated that perceptual-based signal features similar to those employed in the human auditory system can be used to automatically discriminate between target and clutter echoes, thereby reducing the number of false alarms and improving sonar performance. An active sonar experiment on the Malta Plateau in the Mediterranean Sea was conducted during the Clutter07 sea trial and repeated during the Clutter09 sea trial. The dataset consists of more than 95,000 pulse-compressed echoes returned from two targets and many geological clutter objects. These echoes were processed using an automatic classifier that quantifies the timbre of each echo using a number of perceptual signal features. Using echoes from 2007, the aural classifier was trained to establish a boundary between targets and clutter in the feature space. Temporal robustness was then investigated by testing the classifier on echoes from the 2009 experiment.

  16. Delphinid behavioral responses to incidental mid-frequency active sonar.

    PubMed

    Henderson, E Elizabeth; Smith, Michael H; Gassmann, Martin; Wiggins, Sean M; Douglas, Annie B; Hildebrand, John A

    2014-10-01

    Opportunistic observations of behavioral responses by delphinids to incidental mid-frequency active (MFA) sonar were recorded in the Southern California Bight from 2004 through 2008 using visual focal follows, static hydrophones, and autonomous recorders. Sound pressure levels were calculated between 2 and 8 kHz. Surface behavioral responses were observed in 26 groups from at least three species of 46 groups out of five species encountered during MFA sonar incidents. Responses included changes in behavioral state or direction of travel, changes in vocalization rates and call intensity, or a lack of vocalizations while MFA sonar occurred. However, 46% of focal groups not exposed to sonar also changed their behavior, and 43% of focal groups exposed to sonar did not change their behavior. Mean peak sound pressure levels when a behavioral response occurred were around 122 dB re: 1 μPa. Acoustic localizations of dolphin groups exhibiting a response gave insight into nighttime movement patterns and provided evidence that impacts of sonar may be mediated by behavioral state. The lack of response in some cases may indicate a tolerance of or habituation to MFA sonar by local populations; however, the responses that occur at lower received levels may point to some sensitization as well.

  17. Phase calibration of sonar systems using standard targets and dual-frequency transmission pulses.

    PubMed

    Islas-Cital, Alan; Atkins, Philip R; Foo, Kae Y; Picó, Ruben

    2011-10-01

    The phase angle component of the complex frequency response of a sonar system operating near transducer resonance is usually distorted. Interpretation and classification of the received sonar signal benefits from the preservation of waveform fidelity over the full bandwidth. A calibration process that measures the phase response in addition to the amplitude response is thus required. This paper describes an extension to the standard-target calibration method to include phase angle, without affecting the experimental apparatus, by using dual-frequency transmission pulses and frequency-domain data processing. This approach reduces the impact of unknown range and sound speed parameters upon phase calibration accuracy, as target phase is determined from the relationship of the two frequency components instead of relying on a local phase reference. Tungsten carbide spheres of various sizes were used to simultaneously calibrate the amplitude and phase response of an active sonar system in a laboratory tank. Experimental measurements of target phase spectra are in good agreement with values predicted from a theoretical model based upon full-wave analysis, over an operating frequency of 50-125 kHz.

  18. Active sonar, beaked whales and European regional policy.

    PubMed

    Dolman, Sarah J; Evans, Peter G H; Notarbartolo-di-Sciara, Giuseppe; Frisch, Heidrun

    2011-01-01

    Various reviews, resolutions and guidance from international and regional fora have been produced in recent years that acknowledge the significance of marine noise and its potential impacts on cetaceans. Within Europe, ACCOBAMS and ASCOBANS have shown increasing attention to the issue. The literature highlights concerns surrounding the negative impacts of active sonar on beaked whales in particular, where concerns primarily relate to the use of mid-frequency active sonar (1-10kHz), as used particularly in military exercises. The authors review the efforts that European regional policies have undertaken to acknowledge and manage possible negative impacts of active sonar and how these might assist the transition from scientific research to policy implementation, including effective management and mitigation measures at a national level.

  19. Perception-based automatic classification of impulsive-source active sonar echoes.

    PubMed

    Young, Victor W; Hines, Paul C

    2007-09-01

    Impulsive-source active sonar systems are often plagued by false alarm echoes resulting from the presence of naturally occurring clutter objects in the environment. Sonar performance could be improved by a technique for discriminating between echoes from true targets and echoes from clutter. Motivated by anecdotal evidence that target echoes sound very different than clutter echoes when auditioned by a human operator, this paper describes the implementation of an automatic classifier for impulsive-source active sonar echoes that is based on perceptual signal features that have been previously identified in the musical acoustics literature as underlying timbre. Perceptual signal features found in this paper to be particularly useful to the problem of active sonar classification include: the centroid and peak value of the perceptual loudness function, as well as several features based on subband attack and decay times. This paper uses subsets of these perceptual signal features to train and test an automatic classifier capable of discriminating between target and clutter echoes with an equal error rate of roughly 10%; the area under the receiver operating characteristic curve corresponding to this classifier is found to be 0.975.

  20. Active Fish Tracking Sonar (AFTS) for Assessing Fish Behavior

    SciTech Connect

    Hedgepeth, J; Johnson, Gary E. ); Skalski, John R.; Burczynski, J

    2002-11-01

    Active fish tracking sonars (AFTS) were used in 2001 to study fish movement in response to intake occlusion plates at The Dalles Dam on the Columbia River. AFTS provides three-dimensional fish tracks by aligning the axis of a split-beam transducer with a fish target. High-speed stepper motors move the transducer so that a tracked target remains on-axis. Occlusion plates with lateral extensions covered the top half of the turbine intakes to produce a fish friendly near-dam environment. Two AFTS were positioned at the center of Main Unit 1, one each for monitoring installed and removed plate conditions. A regression analysis showed that occlusion plates had pronounced effects on fish movement along the dam. The plates appeared to inhibit movement toward the spillway, movement toward the dam (especially in front of the turbine intake), and movement downward toward the turbines. Fish fate (as opposed to movement directions from regression slopes) into particular areas was determined using Markov-chain analysis. The sluiceway (a safer passage route above the turbine intake) zone of influence was larger with the occlusion plates installed, contrary to the regression results. In addition, the probability of passage out the near turbine and bottom sides of the sample volume was about 50% lower with occlusion plates installed.

  1. Testing of a Composite Wavelet Filter to Enhance Automated Target Recognition in SONAR

    NASA Technical Reports Server (NTRS)

    Chiang, Jeffrey N.

    2011-01-01

    Automated Target Recognition (ATR) systems aim to automate target detection, recognition, and tracking. The current project applies a JPL ATR system to low resolution SONAR and camera videos taken from Unmanned Underwater Vehicles (UUVs). These SONAR images are inherently noisy and difficult to interpret, and pictures taken underwater are unreliable due to murkiness and inconsistent lighting. The ATR system breaks target recognition into three stages: 1) Videos of both SONAR and camera footage are broken into frames and preprocessed to enhance images and detect Regions of Interest (ROIs). 2) Features are extracted from these ROIs in preparation for classification. 3) ROIs are classified as true or false positives using a standard Neural Network based on the extracted features. Several preprocessing, feature extraction, and training methods are tested and discussed in this report.

  2. Object classification and acoustic imaging with active sonar.

    PubMed

    Kelly, J G; Carpenter, R N; Tague, J A

    1992-04-01

    The theoretical underpinnings of underwater acoustic classification and imaging using high-frequency active sonar are studied. All essential components of practical classification systems are incorporated in a Bayesian theoretic framework. The optimum decision rules and array processing are presented and evaluated. A systematic performance evaluation methodology is derived. New results quantify the relationship between classifier performance and object geometry, acoustic imaging, and the accuracy of a priori knowledge infused into the processor.

  3. Digital sonar system

    DOEpatents

    Young, K.K.; Wilkes, R.J.

    1995-11-21

    A transponder of an active digital sonar system identifies a multifrequency underwater activating sonar signal received from a remote sonar transmitter. The transponder includes a transducer that receives acoustic waves, including the activating sonar signal, and generates an analog electrical receipt signal. The analog electrical receipt signal is converted to a digital receipt signal and cross-correlated with a digital transmission signal pattern corresponding to the activating sonar signal. A relative peak in the cross-correlation value is indicative of the activating sonar signal having been received by the transponder. In response to identifying the activating sonar signal, the transponder transmits a responding multifrequency sonar signal. 4 figs.

  4. Digital sonar system

    DOEpatents

    Young, Kenneth K.; Wilkes, R. Jeffrey

    1995-01-01

    A transponder of an active digital sonar system identifies a multifrequency underwater activating sonar signal received from a remote sonar transmitter. The transponder includes a transducer that receives acoustic waves, including the activating sonar signal, and generates an analog electrical receipt signal. The analog electrical receipt signal is converted to a digital receipt signal and cross-correlated with a digital transmission signal pattern corresponding to the activating sonar signal. A relative peak in the cross-correlation value is indicative of the activating sonar signal having been received by the transponder. In response to identifying the activating sonar signal, the transponder transmits a responding multifrequency sonar signal.

  5. Measuring the target strength spectra of fish using dolphin-like short broadband sonar signals.

    PubMed

    Imaizumi, Tomohito; Furusawa, Masahiko; Akamatsu, Tomonari; Nishimori, Yasushi

    2008-12-01

    Dolphins identify their prey using broadband sonar signals. The broadband spectrum of the target strength (TS) of fish is believed to be a key factor in target discrimination. In this study, the TS spectrum was measured using sonar signals generated by two different dolphin species: finless porpoise and bottlenose dolphin. First, the broadband form functions of a tungsten carbide sphere and a copper sphere were measured in a water tank, and a close agreement between measurements and theoretical values was confirmed. Second, the TS spectra of anesthetized fish from three species were measured in a water tank. Although the results showed characteristics similar to previous measurements, they varied among species, individuals, and tilt angles. Third, the TS spectra of live fish suspended and tethered by nylon monofilament lines were measured at sea. The dolphin-like sonar signals were effective in obtaining the broadband TS spectra of the fish. Cross-correlation processing of the echo from a tungsten carbide sphere showed a further advantage of using the dolphin-like sonar signals: the signal-to-noise ratio increased by more than 10 dB. The variation of TS spectra with fish behavior provides useful information for target identification.

  6. A model for sonar interrogation of complex bottom and surface targets in shallow-water waveguides.

    PubMed

    Giddings, Thomas E; Shirron, Joseph J

    2008-04-01

    Many problems of current interest in underwater acoustics involve low-frequency broadband sonar interrogation of objects near the sea surface or sea floor of a shallow-water environment. When the target is situated near the upper or lower boundary of the water column the acoustic interactions with the target objects are complicated by interactions with the nearby free surface or fluid-sediment interface, respectively. A practical numerical method to address such situations is presented. The model provides high levels of accuracy with the flexibility to handle complex, three-dimensional targets in range-independent environments. The model is demonstrated using several bottom target scenarios, with and without locally undulating seabeds. The impact of interface and boundary interactions is considered with an eye toward using the sonar return signal as the basis for acoustic imaging or spectral classification.

  7. Matched-field depth estimation for active sonar.

    PubMed

    Hickman, Granger; Krolik, Jeffrey L

    2004-02-01

    This work concerns the problem of estimating the depth of a submerged scatterer in a shallow-water ocean by using an active sonar and a horizontal receiver array. As in passive matched-field processing (MFP) techniques, numerical modeling of multipath propagation is used to facilitate localization. However, unlike passive MFP methods where estimation of source range is critically dependent on relative modal phase modeling, in active sonar source range is approximately known from travel-time measurements. Thus the proposed matched-field depth estimation (MFDE) method does not require knowledge of the complex relative multipath amplitudes which also depend on the unknown scatterer characteristics. Depth localization is achieved by modeling depth-dependent relative delays and elevation angle spreads between multipaths. A maximum likelihood depth estimate is derived under the assumption that returns from a sequence of pings are uncorrelated and the scatterer is at constant depth. The Cramér-Rao lower bound on depth estimation mean-square-error is computed and compared with Monte Carlo simulation results for a typical range-dependent, shallow-water Mediterranean environment. Depth estimation performance to within 10% of the water column depth is predicted at signal-to-noise ratios of greater than 10 dB. Real data results are reported for depth estimation of an echo repeater to within 10-m accuracy in this same shallow water environment.

  8. Sonar tracking of horizontally moving targets by the big brown bat Eptesicus fuscus.

    PubMed

    Masters, W M; Moffat, A J; Simmons, J A

    1985-06-14

    When following a moving target, echolocating bats (Eptesicus fuscus) keep their heads aimed at the target's position. This tracking behavior seems not to involve predicting the target's trajectory, but is achieved by the bat's pointing its head at the target's last known position. The bat obtains frequent position updates by emitting sonar signals at a high rate. After the lag between head and target positions and the nonunity tracking gain were corrected for, bats' tracking accuracy in the horizontal plane was +/- 1.6 degree.

  9. PMHT Approach for Multi-Target Multi-Sensor Sonar Tracking in Clutter.

    PubMed

    Li, Xiaohua; Li, Yaan; Yu, Jing; Chen, Xiao; Dai, Miao

    2015-01-01

    Multi-sensor sonar tracking has many advantages, such as the potential to reduce the overall measurement uncertainty and the possibility to hide the receiver. However, the use of multi-target multi-sensor sonar tracking is challenging because of the complexity of the underwater environment, especially the low target detection probability and extremely large number of false alarms caused by reverberation. In this work, to solve the problem of multi-target multi-sensor sonar tracking in the presence of clutter, a novel probabilistic multi-hypothesis tracker (PMHT) approach based on the extended Kalman filter (EKF) and unscented Kalman filter (UKF) is proposed. The PMHT can efficiently handle the unknown measurements-to-targets and measurements-to-transmitters data association ambiguity. The EKF and UKF are used to deal with the high degree of nonlinearity in the measurement model. The simulation results show that the proposed algorithm can improve the target tracking performance in a cluttered environment greatly, and its computational load is low. PMID:26561817

  10. PMHT Approach for Multi-Target Multi-Sensor Sonar Tracking in Clutter.

    PubMed

    Li, Xiaohua; Li, Yaan; Yu, Jing; Chen, Xiao; Dai, Miao

    2015-11-06

    Multi-sensor sonar tracking has many advantages, such as the potential to reduce the overall measurement uncertainty and the possibility to hide the receiver. However, the use of multi-target multi-sensor sonar tracking is challenging because of the complexity of the underwater environment, especially the low target detection probability and extremely large number of false alarms caused by reverberation. In this work, to solve the problem of multi-target multi-sensor sonar tracking in the presence of clutter, a novel probabilistic multi-hypothesis tracker (PMHT) approach based on the extended Kalman filter (EKF) and unscented Kalman filter (UKF) is proposed. The PMHT can efficiently handle the unknown measurements-to-targets and measurements-to-transmitters data association ambiguity. The EKF and UKF are used to deal with the high degree of nonlinearity in the measurement model. The simulation results show that the proposed algorithm can improve the target tracking performance in a cluttered environment greatly, and its computational load is low.

  11. PMHT Approach for Multi-Target Multi-Sensor Sonar Tracking in Clutter

    PubMed Central

    Li, Xiaohua; Li, Yaan; Yu, Jing; Chen, Xiao; Dai, Miao

    2015-01-01

    Multi-sensor sonar tracking has many advantages, such as the potential to reduce the overall measurement uncertainty and the possibility to hide the receiver. However, the use of multi-target multi-sensor sonar tracking is challenging because of the complexity of the underwater environment, especially the low target detection probability and extremely large number of false alarms caused by reverberation. In this work, to solve the problem of multi-target multi-sensor sonar tracking in the presence of clutter, a novel probabilistic multi-hypothesis tracker (PMHT) approach based on the extended Kalman filter (EKF) and unscented Kalman filter (UKF) is proposed. The PMHT can efficiently handle the unknown measurements-to-targets and measurements-to-transmitters data association ambiguity. The EKF and UKF are used to deal with the high degree of nonlinearity in the measurement model. The simulation results show that the proposed algorithm can improve the target tracking performance in a cluttered environment greatly, and its computational load is low. PMID:26561817

  12. 75 FR 81284 - Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ... SECURITY Coast Guard Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology... of High Frequency (HF) and Ultra High Frequency (UHF) Sound Navigation and Ranging (SONAR) Technology... in the January 17, 2008, issue of the Federal Register (73 FR 3316). Background and Purpose...

  13. 78 FR 70567 - Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Final...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-26

    ... SECURITY Coast Guard Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology...) and Ultra High Frequency (UHF) Sound Navigation and Ranging (SONAR) Technology and Finding of No... less than two weeks; however, for environmental disasters such as the Deepwater Horizon oil...

  14. Investigation of measureable parameters that correlate with automatic target recognition performance in synthetic aperture sonar

    NASA Astrophysics Data System (ADS)

    Gazagnaire, Julia; Cobb, J. T.; Isaacs, Jason

    2015-05-01

    There is a desire in the Mine Counter Measure community to develop a systematic method to predict and/or estimate the performance of Automatic Target Recognition (ATR) algorithms that are detecting and classifying mine-like objects within sonar data. Ideally, parameters exist that can be measured directly from the sonar data that correlate with ATR performance. In this effort, two metrics were analyzed for their predictive potential using high frequency synthetic aperture sonar (SAS) images. The first parameter is a measure of contrast. It is essentially the variance in pixel intensity over a fixed partition of relatively small size. An analysis was performed to determine the optimum block size for this contrast calculation. These blocks were then overlapped in the horizontal and vertical direction over the entire image. The second parameter is the one-dimensional K-shape parameter. The K-distribution is commonly used to describe sonar backscatter return from range cells that contain a finite number of scatterers. An Ada-Boosted Decision Tree classifier was used to calculate the probability of classification (Pc) and false alarm rate (FAR) for several types of targets in SAS images from three different data sets. ROC curves as a function of the measured parameters were generated and the correlation between the measured parameters in the vicinity of each of the contacts and the ATR performance was investigated. The contrast and K-shape parameters were considered separately. Additionally, the contrast and K-shape parameter were associated with background texture types using previously labeled high frequency SAS images.

  15. Performances of human listeners and an automatic aural classifier in discriminating between sonar target echoes and clutter.

    PubMed

    Allen, Nancy; Hines, Paul C; Young, Victor W

    2011-09-01

    Human listening tests were conducted to investigate if participants could distinguish between samples of target echoes and clutter obtained from a broadband active sonar experiment. For each echo, the listeners assigned a rating based on how confident they were that it was a target echo or clutter. The measure of performance was the area under the binormal receiver-operating-characteristic (ROC) curve, A(z). The mean performance was A(z)=0.95 ± 0.04 when signals were presented with their full available acoustic bandwidth of approximately 0-2 kHz. It was A(z)=0.77 ± 0.08 when the bandwidth was reduced to 0.5-2 kHz. The error bounds are stated as 95% confidence intervals. These results show that the listeners could definitely hear differences, but their performance was significantly degraded when the low-frequency signal information was removed. The performance of an automatic aural classifier was compared against this human-performance baseline. Results of statistical tests showed that it outperformed 2 of 13 listeners and 5 of 9 human listeners in the full-bandwidth and reduced-bandwidth tests, respectively, and performed similarly to the other listeners. Given its performance, the automatic aural classifier may prove beneficial to Navy sonar systems.

  16. Continuous transmission frequency modulation detection under variable sonar-target speed conditions.

    PubMed

    Wang, Yang; Yang, Jun

    2013-03-13

    As a ranging sensor, a continuous transmission frequency modulation (CTFM) sonar with its ability for range finding and range profile formation works effectively under stationary conditions. When a relative velocity exists between the target and the sonar, the echo signal is Doppler-shifted. This situation causes the output of the sensor to deviate from the actual target range, thus limiting its applications to stationary conditions only. This work presents an approach for correcting such a deviation. By analyzing the Doppler effect during the propagation process, the sensor output can be corrected by a Doppler factor. To obtain this factor, a conventional CTFM system is slightly modified by adding a single tone signal with a frequency that locates out-of-sweep range of the transmitted signal. The Doppler factor can be extracted from the echo. Both verification experiments and performance tests are carried out. Results indicate the validity of the proposed approach. Moreover, ranging precision under different processing setups is discussed. For adjacent multiple targets, the discrimination ability is influenced by displacement and velocity. A discrimination boundary is provided through an analysis.

  17. Continuous transmission frequency modulation detection under variable sonar-target speed conditions.

    PubMed

    Wang, Yang; Yang, Jun

    2013-01-01

    As a ranging sensor, a continuous transmission frequency modulation (CTFM) sonar with its ability for range finding and range profile formation works effectively under stationary conditions. When a relative velocity exists between the target and the sonar, the echo signal is Doppler-shifted. This situation causes the output of the sensor to deviate from the actual target range, thus limiting its applications to stationary conditions only. This work presents an approach for correcting such a deviation. By analyzing the Doppler effect during the propagation process, the sensor output can be corrected by a Doppler factor. To obtain this factor, a conventional CTFM system is slightly modified by adding a single tone signal with a frequency that locates out-of-sweep range of the transmitted signal. The Doppler factor can be extracted from the echo. Both verification experiments and performance tests are carried out. Results indicate the validity of the proposed approach. Moreover, ranging precision under different processing setups is discussed. For adjacent multiple targets, the discrimination ability is influenced by displacement and velocity. A discrimination boundary is provided through an analysis. PMID:23486221

  18. The Subarray MVDR Beamformer: A Space-Time Adaptive Processor Applied to Active Sonar

    NASA Astrophysics Data System (ADS)

    Bezanson, Leverett Guidroz

    The research for this thesis was mainly performed at the NATO Underwater Research Center, now named the Center for Maritime Research and Experimentation (CMRE). The purpose of the research was to improve the detection of underwater targets in the littoral ocean when using active sonar. Currently these detections are being made by towed line arrays using a delay and sum beamformer for bearing measurements and noise suppression. This method of beamforming has can suffer from reverberation that commonly is present in the littoral environment. A proposed solution is to use an adaptive beamformer which can attenuate reverberation and increase the bearing resolution. The adaptive beamforming algorithms have existed for a long time and typically are not used in the active case due to limited amount of observable data that is needed for adaptation. This deficiency is caused by the conflicting requirements for high Doppler resolution for target detection and small time windows for building up full-rank covariance estimates. The algorithms also are sensitive to bearing estimate errors that commonly occur in active sonar systems. Recently it has been proposed to overcome these limitations through the use of reduced beamspace adaptive beamforming. The Subarray MVDR beamformer is analyzed, both against simulated data and against experimental data collected by CMRE during the GLINT/NGAS11 experiment in 2011. Simulation results indicate that the Subarray MVDR beamformer rejects interfering signals that are not effectively attenuated by conventional beamforming. The application of the Subarray MVDR beamformer to the experimental data shows that the Doppler spread of the reverberation ridge is reduced, and the bearing resolution improved. The signal to noise ratio is calculated at the target location and also shows improvement. These calculated and observed performance metrics indicate an improvement of detection in reverberation noise.

  19. Can the elongated hindwing tails of fluttering moths serve as false sonar targets to divert bat attacks?

    PubMed

    Lee, Wu-Jung; Moss, Cynthia F

    2016-05-01

    It has long been postulated that the elongated hindwing tails of many saturniid moths have evolved to create false sonar targets to divert the attack of echolocation-guided bat predators. However, rigorous echo-acoustic evidence to support this hypothesis has been lacking. In this study, fluttering luna moths (Actias luna), a species with elongated hindwing tails, were ensonified with frequency modulated chirp signals from all angles of orientation and across the wingbeat cycle. High-speed stereo videography was combined with pulse compression sonar processing to characterize the echo information available to foraging bats. Contrary to previous suggestions, the results show that the tail echoes are weak and do not dominate the sonar returns, compared to the large, planar wings and the moth body. However, the distinctive twisted morphology of the tails create persistent echoes across all angles of orientation, which may induce erroneous sonar target localization and disrupt accurate tracking by echolocating bats. These findings thus suggest a refinement of the false target hypothesis to emphasize sonar localization errors induced by the twisted tails, and highlight the importance of physics-based approaches to study the sensory information involved in the evolutionary arms race between moths and their bat predators. PMID:27250152

  20. Can the elongated hindwing tails of fluttering moths serve as false sonar targets to divert bat attacks?

    PubMed

    Lee, Wu-Jung; Moss, Cynthia F

    2016-05-01

    It has long been postulated that the elongated hindwing tails of many saturniid moths have evolved to create false sonar targets to divert the attack of echolocation-guided bat predators. However, rigorous echo-acoustic evidence to support this hypothesis has been lacking. In this study, fluttering luna moths (Actias luna), a species with elongated hindwing tails, were ensonified with frequency modulated chirp signals from all angles of orientation and across the wingbeat cycle. High-speed stereo videography was combined with pulse compression sonar processing to characterize the echo information available to foraging bats. Contrary to previous suggestions, the results show that the tail echoes are weak and do not dominate the sonar returns, compared to the large, planar wings and the moth body. However, the distinctive twisted morphology of the tails create persistent echoes across all angles of orientation, which may induce erroneous sonar target localization and disrupt accurate tracking by echolocating bats. These findings thus suggest a refinement of the false target hypothesis to emphasize sonar localization errors induced by the twisted tails, and highlight the importance of physics-based approaches to study the sensory information involved in the evolutionary arms race between moths and their bat predators.

  1. Method for shaping and aiming narrow beams. [sonar mapping and target identification

    NASA Technical Reports Server (NTRS)

    Heyser, R. C. (Inventor)

    1981-01-01

    A sonar method and apparatus is discribed which utilizes a linear frequency chirp in a transmitter/receiver having a correlator to synthesize a narrow beamwidth pattern from otherwise broadbeam transducers when there is relative velocity between the transmitter/receiver and the target. The chirp is so produced in a generator in bandwidth, B, and time, T, as to produce a time bandwidth product, TB, that is increased for a narrower angle. A replica of the chirp produced in a generator is time delayed and Doppler shifted for use as a reference in the receiver for correlation of received chirps from targets. This reference is Doppler shifted to select targets preferentially, thereby to not only synthesize a narrow beam but also aim the beam in azimuth and elevation.

  2. An automatic ellipse and line targets detection method from synthetic aperture sonar images

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Li, Bao-Li; Liu, Ji-Yuan; Zhang, Chun-Hua

    2009-10-01

    Detection of ellipse and line targets is important for the analysis of Synthetic Aperture Sonar (SAS) images. An automatic ellipse and line targets detection method from synthetic aperture sonar images is presented. The method mainly has three procedures: preprocessing of SAS images, Zernike Orthogonal Moment Edge Detection Algorithm (ZOMEDA), line and ellipse detection. The guidance is presented firstly on how to perform the preprocessing of SAS images. Then, ZOMEDA is utilized to produce edge points with both the direction and position information. Principles of ZOMEDA with the 7x7 template are analyzed and the coefficients to carry out the ZOMEDA are calculated and listed. The idea of Random Sample Consensus (RANSAC) is applied to the Line and ellipse detection procedure to improve the robustness and the computing efficiency. Detail procedures of RANSAC are analyzed in the article. Calculating of line and ellipse parameters is pivotal to carry out the idea of RANSAC. Principles are analyzed on how to calculate the parameters of the line and ellipse based on the direction and position information. Another important procedure, parameters refinement, is also discussed. At last, the line and ellipse detection method is applied to simulated datasets and lake-trial datasets for validation.

  3. First direct measurements of behavioural responses by Cuvier's beaked whales to mid-frequency active sonar.

    PubMed

    DeRuiter, Stacy L; Southall, Brandon L; Calambokidis, John; Zimmer, Walter M X; Sadykova, Dinara; Falcone, Erin A; Friedlaender, Ari S; Joseph, John E; Moretti, David; Schorr, Gregory S; Thomas, Len; Tyack, Peter L

    2013-08-23

    Most marine mammal- strandings coincident with naval sonar exercises have involved Cuvier's beaked whales (Ziphius cavirostris). We recorded animal movement and acoustic data on two tagged Ziphius and obtained the first direct measurements of behavioural responses of this species to mid-frequency active (MFA) sonar signals. Each recording included a 30-min playback (one 1.6-s simulated MFA sonar signal repeated every 25 s); one whale was also incidentally exposed to MFA sonar from distant naval exercises. Whales responded strongly to playbacks at low received levels (RLs; 89-127 dB re 1 µPa): after ceasing normal fluking and echolocation, they swam rapidly, silently away, extending both dive duration and subsequent non-foraging interval. Distant sonar exercises (78-106 dB re 1 µPa) did not elicit such responses, suggesting that context may moderate reactions. The observed responses to playback occurred at RLs well below current regulatory thresholds; equivalent responses to operational sonars could elevate stranding risk and reduce foraging efficiency.

  4. First direct measurements of behavioural responses by Cuvier's beaked whales to mid-frequency active sonar

    PubMed Central

    DeRuiter, Stacy L.; Southall, Brandon L.; Calambokidis, John; Zimmer, Walter M. X.; Sadykova, Dinara; Falcone, Erin A.; Friedlaender, Ari S.; Joseph, John E.; Moretti, David; Schorr, Gregory S.; Thomas, Len; Tyack, Peter L.

    2013-01-01

    Most marine mammal­ strandings coincident with naval sonar exercises have involved Cuvier's beaked whales (Ziphius cavirostris). We recorded animal movement and acoustic data on two tagged Ziphius and obtained the first direct measurements of behavioural responses of this species to mid-frequency active (MFA) sonar signals. Each recording included a 30-min playback (one 1.6-s simulated MFA sonar signal repeated every 25 s); one whale was also incidentally exposed to MFA sonar from distant naval exercises. Whales responded strongly to playbacks at low received levels (RLs; 89–127 dB re 1 µPa): after ceasing normal fluking and echolocation, they swam rapidly, silently away, extending both dive duration and subsequent non-foraging interval. Distant sonar exercises (78–106 dB re 1 µPa) did not elicit such responses, suggesting that context may moderate reactions. The observed responses to playback occurred at RLs well below current regulatory thresholds; equivalent responses to operational sonars could elevate stranding risk and reduce foraging efficiency. PMID:23825085

  5. Optimization of Adaboost Algorithm for Sonar Target Detection in a Multi-Stage ATR System

    NASA Technical Reports Server (NTRS)

    Lin, Tsung Han (Hank)

    2011-01-01

    JPL has developed a multi-stage Automated Target Recognition (ATR) system to locate objects in images. First, input images are preprocessed and sent to a Grayscale Optical Correlator (GOC) filter to identify possible regions-of-interest (ROIs). Second, feature extraction operations are performed using Texton filters and Principal Component Analysis (PCA). Finally, the features are fed to a classifier, to identify ROIs that contain the targets. Previous work used the Feed-forward Back-propagation Neural Network for classification. In this project we investigate a version of Adaboost as a classifier for comparison. The version we used is known as GentleBoost. We used the boosted decision tree as the weak classifier. We have tested our ATR system against real-world sonar images using the Adaboost approach. Results indicate an improvement in performance over a single Neural Network design.

  6. Using artificial bat sonar neural networks for complex pattern recognition: recognizing faces and the speed of a moving target.

    PubMed

    Dror, I E; Florer, F L; Rios, D; Zagaeski, M

    1996-04-01

    Two sets of studies examined the viability of using bat-like sonar input for artificial neural networks in complex pattern recognition tasks. In the first set of studies, a sonar neural network was required to perform two face recognition tasks. In the first task, the network was trained to recognize different faces regardless of facial expressions. Following training, the network was tested on its ability to generalize and correctly recognize faces using echoes of novel facial expressions that were not included in the training set. The neural network was able to recognize novel echoes of faces almost perfectly (above 96% accuracy) when it was required to recognize up to five faces. In the second face recognition task, a sonar neural network was trained to recognize the sex of 16 faces (eight males and eight females). After training, the network was able to correctly recognize novel echoes of those faces as 'male' or as 'female' faces with accuracy levels of 88%. However, the network was not able to recognize novel faces as 'male' or 'female' faces. In the second set of studies, a sonar neural network was required to learn to recognize the speed of a target that was moving towards the viewer. During training, the target was presented in a variety of orientations, and the network's performance was evaluated when the target was presented in novel orientations that were not included in the training set. The different orientations dramatically affected the amplitude and the frequency composition of the echoes. The neural network was able to learn and recognize the speed of a moving target, and to generalize to new orientations of the target. However, the network was not able to generalize to new speeds that were not included in the training set. The potential and limitations of using bat-like sonar as input for artifical neural networks are discussed.

  7. 77 FR 52317 - Record of Decision for Surveillance Towed Array Sensor System Low Frequency Active Sonar

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-29

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Department of the Navy Record of Decision for Surveillance Towed Array Sensor System Low Frequency Active... Array Sensor System Low Frequency Active (SURTASS LFA) sonar systems with certain...

  8. Target flutter rate discrimination by bats using frequency-modulated sonar sounds: behavior and signal processing models.

    PubMed

    Grossetête, A; Moss, C F

    1998-04-01

    This study utilized psychophysical data and acoustical measurements of sonar echoes from artificial fluttering targets to develop insights to the information used by FM bats to discriminate the wingbeat rate of flying insects. Fluttering targets were produced by rotating blades that moved towards the bat, and the animal learned to discriminate between two rates of movement, a reference rate (30 or 50 Hz) and a slower, variable rate. Threshold discrimination performance depended on the rotation rate of the reference target, with a difference value of 9 Hz for the reference rate of 30 Hz and 14 Hz for the reference rate of 50 Hz. Control experiments demonstrated that the bats used sonar echoes from the moving targets to perform the discrimination task. Acoustical measurements showed that the moving target produced a Doppler shift in the echo and a concomitant change in the arrival time of each frequency in the linear period FM sweep. The difference in delay between echoes from moving and stationary parts varied linearly with flutter rate and depended on the characteristics of the bat's sonar sounds. Simulations also showed a reduction in average echo bandwidth with increasing flutter rate, which may account for a higher delay discrimination threshold using the 50-Hz reference rate. This work suggests that Doppler-induced changes in echo delays produced by fluttering targets may contribute to the FM bat's perception of flying insect prey.

  9. A rail system for circular synthetic aperture sonar imaging and acoustic target strength measurements: Design/operation/preliminary results

    NASA Astrophysics Data System (ADS)

    Kennedy, J. L.; Marston, T. M.; Lee, K.; Lopes, J. L.; Lim, R.

    2014-01-01

    A 22 m diameter circular rail, outfitted with a mobile sonar tower trolley, was designed, fabricated, instrumented with underwater acoustic transducers, and assembled on a 1.5 m thick sand layer at the bottom of a large freshwater pool to carry out sonar design and target scattering response studies. The mobile sonar tower translates along the rail via a drive motor controlled by customized LabVIEW software. The rail system is modular and assembly consists of separately deploying eight circular arc sections, measuring a nominal center radius of 11 m and 8.64 m arc length each, and having divers connect them together in the underwater environment. The system enables full scale measurements on targets of interest with 0.1° angular resolution over a complete 360° aperture, without disrupting target setup, and affording a level of control over target environment conditions and noise sources unachievable in standard field measurements. In recent use, the mobile cart carrying an instrumented sonar tower was translated along the rail in 720 equal position increments and acoustic backscatter data were acquired at each position. In addition, this system can accommodate both broadband monostatic and bistatic scattering measurements on targets of interest, allowing capture of target signature phenomena under diverse configurations to address current scientific and technical issues encountered in mine countermeasure and unexploded ordnance applications. In the work discussed here, the circular rail apparatus is used for acoustic backscatter testing, but this system also has the capacity to facilitate the acquisition of magnetic and optical sensor data from targets of interest. A brief description of the system design and operation will be presented along with preliminary processed results for data acquired from acoustic measurements conducted at the Naval Surface Warfare Center, Panama City Division Test Pond Facility. [Work Supported by the U.S. Office of Naval Research and

  10. A rail system for circular synthetic aperture sonar imaging and acoustic target strength measurements: design/operation/preliminary results.

    PubMed

    Kennedy, J L; Marston, T M; Lee, K; Lopes, J L; Lim, R

    2014-01-01

    A 22 m diameter circular rail, outfitted with a mobile sonar tower trolley, was designed, fabricated, instrumented with underwater acoustic transducers, and assembled on a 1.5 m thick sand layer at the bottom of a large freshwater pool to carry out sonar design and target scattering response studies. The mobile sonar tower translates along the rail via a drive motor controlled by customized LabVIEW software. The rail system is modular and assembly consists of separately deploying eight circular arc sections, measuring a nominal center radius of 11 m and 8.64 m arc length each, and having divers connect them together in the underwater environment. The system enables full scale measurements on targets of interest with 0.1° angular resolution over a complete 360° aperture, without disrupting target setup, and affording a level of control over target environment conditions and noise sources unachievable in standard field measurements. In recent use, the mobile cart carrying an instrumented sonar tower was translated along the rail in 720 equal position increments and acoustic backscatter data were acquired at each position. In addition, this system can accommodate both broadband monostatic and bistatic scattering measurements on targets of interest, allowing capture of target signature phenomena under diverse configurations to address current scientific and technical issues encountered in mine countermeasure and unexploded ordnance applications. In the work discussed here, the circular rail apparatus is used for acoustic backscatter testing, but this system also has the capacity to facilitate the acquisition of magnetic and optical sensor data from targets of interest. A brief description of the system design and operation will be presented along with preliminary processed results for data acquired from acoustic measurements conducted at the Naval Surface Warfare Center, Panama City Division Test Pond Facility. [Work Supported by the U.S. Office of Naval Research and

  11. Modeling human echolocation of near-range targets with an audible sonar.

    PubMed

    Kuc, Roman; Kuc, Victor

    2016-02-01

    Blind humans echolocate nearby targets by emitting palatal clicks and perceiving echoes that the auditory system is not able to resolve temporally. The mechanism for perceiving near-range echoes is not known. This paper models the direct mouth-to-ear signal (MES) and the echo to show that the echo enhances the high-frequency components in the composite MES/echo signal with features that allow echolocation. The mouth emission beam narrows with increasing frequency and exhibits frequency-dependent transmission notches in the backward direction toward the ears as predicted by the piston-in-sphere model. The ears positioned behind the mouth detect a MES that contains predominantly the low frequencies contained in the emission. Hence the high-frequency components in the emission that are perceived by the ears are enhanced by the echoes. A pulse/echo audible sonar verifies this model by echolocating targets from 5 cm range, where the MES and echo overlap significantly, to 55 cm. The model predicts that unambiguous ranging occurs over a limited range and that there is an optimal range that produces the highest range resolution. PMID:26936542

  12. Modeling human echolocation of near-range targets with an audible sonar.

    PubMed

    Kuc, Roman; Kuc, Victor

    2016-02-01

    Blind humans echolocate nearby targets by emitting palatal clicks and perceiving echoes that the auditory system is not able to resolve temporally. The mechanism for perceiving near-range echoes is not known. This paper models the direct mouth-to-ear signal (MES) and the echo to show that the echo enhances the high-frequency components in the composite MES/echo signal with features that allow echolocation. The mouth emission beam narrows with increasing frequency and exhibits frequency-dependent transmission notches in the backward direction toward the ears as predicted by the piston-in-sphere model. The ears positioned behind the mouth detect a MES that contains predominantly the low frequencies contained in the emission. Hence the high-frequency components in the emission that are perceived by the ears are enhanced by the echoes. A pulse/echo audible sonar verifies this model by echolocating targets from 5 cm range, where the MES and echo overlap significantly, to 55 cm. The model predicts that unambiguous ranging occurs over a limited range and that there is an optimal range that produces the highest range resolution.

  13. Patterns of Occurrence and Marine Mammal Acoustic Behavior in Relation to Navy Sonar Activity Off Jacksonville, Florida.

    PubMed

    Oswald, Julie N; Norris, Thomas F; Yack, Tina M; Ferguson, Elizabeth L; Kumar, Anurag; Nissen, Jene; Bell, Joel

    2016-01-01

    Passive acoustic data collected from marine autonomous recording units deployed off Jacksonville, FL (from 13 September to 8 October 2009 and 3 December 2009 to 8 January 2010), were analyzed for detection of cetaceans and Navy sonar. Cetaceans detected included Balaenoptera acutorostrata, Eubalaena glacialis, B. borealis, Physeter macrocephalus, blackfish, and delphinids. E. glacialis were detected at shallow and, somewhat unexpectedly, deep sites. P. macrocephalus were characterized by a strong diel pattern. B. acutorostrata showed the strongest relationship between sonar activity and vocal behavior. These results provide a preliminary assessment of cetacean occurrence off Jacksonville and new insights on vocal responses to sonar.

  14. Patterns of Occurrence and Marine Mammal Acoustic Behavior in Relation to Navy Sonar Activity Off Jacksonville, Florida.

    PubMed

    Oswald, Julie N; Norris, Thomas F; Yack, Tina M; Ferguson, Elizabeth L; Kumar, Anurag; Nissen, Jene; Bell, Joel

    2016-01-01

    Passive acoustic data collected from marine autonomous recording units deployed off Jacksonville, FL (from 13 September to 8 October 2009 and 3 December 2009 to 8 January 2010), were analyzed for detection of cetaceans and Navy sonar. Cetaceans detected included Balaenoptera acutorostrata, Eubalaena glacialis, B. borealis, Physeter macrocephalus, blackfish, and delphinids. E. glacialis were detected at shallow and, somewhat unexpectedly, deep sites. P. macrocephalus were characterized by a strong diel pattern. B. acutorostrata showed the strongest relationship between sonar activity and vocal behavior. These results provide a preliminary assessment of cetacean occurrence off Jacksonville and new insights on vocal responses to sonar. PMID:26611034

  15. Using McDaniel's model to represent non-Rayleigh active sonar reverberation

    NASA Astrophysics Data System (ADS)

    Gu, Ming

    Reverberation in active sonar systems has often been observed to follow non-Rayleigh distributions. Current statistical models tend to be either too restrictive, leading to significant mismatch error, or too general, leading to large estimation error. McDaniel's model has shown promise as having reasonably tight representation in terms of skewness and kurtosis for reverberation from a variety of sonar systems. This dissertation intensively explores capability and effectiveness of the generalized McDaniel's model in representing non-Rayleigh reverberation when minimal data are available. Three major topics are covered in this dissertation. First, derivation and computation of the cumulative distribution function of McDaniel's model is addressed. Two approaches, one based on direct integration and the other via characteristic function inversion, are both shown to achieve adequate precision with the former leading to a closed-form solution and the latter requiring significantly less computational effort. Second, parameter estimators using both method of moments (MM) and maximum likelihood (ML) algorithms are developed. The MM estimator has the advantage of a simple and rapid implementation, but the disadvantage of a non- zero probability of a solution not existing. Bootstrap/pruning techniques are proposed to partially deal with the failure of this method. The ML estimator will always provide a solution; however, it requires multivariate optimization. The expectation-maximization (EM) algorithm iteration is also derived for obtaining the ML estimates and compared with the simplex method and quasi-Newton multivariate optimization routines. Furthermore, the ability of various statistical models to represent the probability of false alarm is evaluated as a function of sample size. It is demonstrated that when minimal data are available, McDaniel's model can more accurately represent non-Rayleigh reverberation than the K or Rayleigh mixture models. Third, detection

  16. The effects of high-intensity, low-frequency active sonar on rainbow trout.

    PubMed

    Popper, Arthur N; Halvorsen, Michele B; Kane, Andrew; Miller, Diane L; Smith, Michael E; Song, Jiakun; Stein, Peter; Wysocki, Lidia E

    2007-07-01

    This study investigated the effects on rainbow trout (Oncorhynchus mykiss) of exposure to high-intensity, low-frequency sonar using an element of the standard Surveillance Towed Array Sensor System Low Frequency Active (LFA) sonar source array. Effects of the LFA sonar on hearing were tested using auditory brainstem responses. Effects were also examined on inner ear morphology using scanning electron microscopy and on nonauditory tissues using general pathology and histopathology. Animals were exposed to a maximum received rms sound pressure level of 193 dB re 1 microPa(2) for 324 or 648 s, an exposure that is far in excess of any exposure a fish would normally encounter in the wild. The most significant effect was a 20-dB auditory threshold shift at 400 Hz. However, the results varied with different groups of trout, suggesting developmental and/or genetic impacts on how sound exposure affects hearing. There was no fish mortality during or after exposure. Sensory tissue of the inner ears did not show morphological damage even several days post-sound exposure. Similarly, gross- and histopathology observations demonstrated no effects on nonauditory tissues.

  17. A risk function for behavioral disruption of Blainville's beaked whales (Mesoplodon densirostris) from mid-frequency active sonar.

    PubMed

    Moretti, David; Thomas, Len; Marques, Tiago; Harwood, John; Dilley, Ashley; Neales, Bert; Shaffer, Jessica; McCarthy, Elena; New, Leslie; Jarvis, Susan; Morrissey, Ronald

    2014-01-01

    There is increasing concern about the potential effects of noise pollution on marine life in the world's oceans. For marine mammals, anthropogenic sounds may cause behavioral disruption, and this can be quantified using a risk function that relates sound exposure to a measured behavioral response. Beaked whales are a taxon of deep diving whales that may be particularly susceptible to naval sonar as the species has been associated with sonar-related mass stranding events. Here we derive the first empirical risk function for Blainville's beaked whales (Mesoplodon densirostris) by combining in situ data from passive acoustic monitoring of animal vocalizations and navy sonar operations with precise ship tracks and sound field modeling. The hydrophone array at the Atlantic Undersea Test and Evaluation Center, Bahamas, was used to locate vocalizing groups of Blainville's beaked whales and identify sonar transmissions before, during, and after Mid-Frequency Active (MFA) sonar operations. Sonar transmission times and source levels were combined with ship tracks using a sound propagation model to estimate the received level (RL) at each hydrophone. A generalized additive model was fitted to data to model the presence or absence of the start of foraging dives in 30-minute periods as a function of the corresponding sonar RL at the hydrophone closest to the center of each group. This model was then used to construct a risk function that can be used to estimate the probability of a behavioral change (cessation of foraging) the individual members of a Blainville's beaked whale population might experience as a function of sonar RL. The function predicts a 0.5 probability of disturbance at a RL of 150 dBrms re µPa (CI: 144 to 155) This is 15dB lower than the level used historically by the US Navy in their risk assessments but 10 dB higher than the current 140 dB step-function. PMID:24465477

  18. A risk function for behavioral disruption of Blainville's beaked whales (Mesoplodon densirostris) from mid-frequency active sonar.

    PubMed

    Moretti, David; Thomas, Len; Marques, Tiago; Harwood, John; Dilley, Ashley; Neales, Bert; Shaffer, Jessica; McCarthy, Elena; New, Leslie; Jarvis, Susan; Morrissey, Ronald

    2014-01-01

    There is increasing concern about the potential effects of noise pollution on marine life in the world's oceans. For marine mammals, anthropogenic sounds may cause behavioral disruption, and this can be quantified using a risk function that relates sound exposure to a measured behavioral response. Beaked whales are a taxon of deep diving whales that may be particularly susceptible to naval sonar as the species has been associated with sonar-related mass stranding events. Here we derive the first empirical risk function for Blainville's beaked whales (Mesoplodon densirostris) by combining in situ data from passive acoustic monitoring of animal vocalizations and navy sonar operations with precise ship tracks and sound field modeling. The hydrophone array at the Atlantic Undersea Test and Evaluation Center, Bahamas, was used to locate vocalizing groups of Blainville's beaked whales and identify sonar transmissions before, during, and after Mid-Frequency Active (MFA) sonar operations. Sonar transmission times and source levels were combined with ship tracks using a sound propagation model to estimate the received level (RL) at each hydrophone. A generalized additive model was fitted to data to model the presence or absence of the start of foraging dives in 30-minute periods as a function of the corresponding sonar RL at the hydrophone closest to the center of each group. This model was then used to construct a risk function that can be used to estimate the probability of a behavioral change (cessation of foraging) the individual members of a Blainville's beaked whale population might experience as a function of sonar RL. The function predicts a 0.5 probability of disturbance at a RL of 150 dBrms re µPa (CI: 144 to 155) This is 15dB lower than the level used historically by the US Navy in their risk assessments but 10 dB higher than the current 140 dB step-function.

  19. A Risk Function for Behavioral Disruption of Blainville’s Beaked Whales (Mesoplodon densirostris) from Mid-Frequency Active Sonar

    PubMed Central

    Moretti, David; Thomas, Len; Marques, Tiago; Harwood, John; Dilley, Ashley; Neales, Bert; Shaffer, Jessica; McCarthy, Elena; New, Leslie; Jarvis, Susan; Morrissey, Ronald

    2014-01-01

    There is increasing concern about the potential effects of noise pollution on marine life in the world’s oceans. For marine mammals, anthropogenic sounds may cause behavioral disruption, and this can be quantified using a risk function that relates sound exposure to a measured behavioral response. Beaked whales are a taxon of deep diving whales that may be particularly susceptible to naval sonar as the species has been associated with sonar-related mass stranding events. Here we derive the first empirical risk function for Blainville’s beaked whales (Mesoplodon densirostris) by combining in situ data from passive acoustic monitoring of animal vocalizations and navy sonar operations with precise ship tracks and sound field modeling. The hydrophone array at the Atlantic Undersea Test and Evaluation Center, Bahamas, was used to locate vocalizing groups of Blainville’s beaked whales and identify sonar transmissions before, during, and after Mid-Frequency Active (MFA) sonar operations. Sonar transmission times and source levels were combined with ship tracks using a sound propagation model to estimate the received level (RL) at each hydrophone. A generalized additive model was fitted to data to model the presence or absence of the start of foraging dives in 30-minute periods as a function of the corresponding sonar RL at the hydrophone closest to the center of each group. This model was then used to construct a risk function that can be used to estimate the probability of a behavioral change (cessation of foraging) the individual members of a Blainville’s beaked whale population might experience as a function of sonar RL. The function predicts a 0.5 probability of disturbance at a RL of 150dBrms re µPa (CI: 144 to 155) This is 15dB lower than the level used historically by the US Navy in their risk assessments but 10 dB higher than the current 140 dB step-function. PMID:24465477

  20. Gain control in the sonar of odontocetes.

    PubMed

    Ya Supin, Alexander; Nachtigall, Paul E

    2013-06-01

    The sonar of odontocetes processes echo-signals within a wide range of echo levels. The level of echoes varies widely by tens of decibels depending on the level of the emitted sonar pulse, the target strength, the distance to the target, and the sound absorption by the water media. The auditory system of odontocetes must be capable of effective perception, analysis, and discrimination of echo-signals within all this variability. The sonar of odontocetes has several mechanisms to compensate for the echo-level variation (gain control). To date, several mechanisms of the biosonar gain control have been revealed in odontocetes: (1) adjustment of emitted sonar pulse levels (the longer the distance to the target, the higher the level of the emitted pulse), (2) short-term variation of hearing sensitivity based on forward masking of the echo by the preceding self-heard emitted pulse and subsequent release from the masking, and (3) active long-term control of hearing sensitivity. Recent investigations with the use of the auditory evoked-potential technique have demonstrated that these mechanisms effectively minimize the variation of the response to the echo when either the emitted sonar pulse level, or the target distance, or both vary within a wide range. A short review of these data is presented herein.

  1. Striation-based beamforming for active sonar with a horizontal line array.

    PubMed

    Zurk, Lisa M; Rouseff, Daniel

    2012-10-01

    A physics-based method for beamforming signals measured on a horizontal array is developed with an application to underwater active sonar systems. The proposed striation-based beamformer coherently combines the pressure from each element in the array at different frequencies, and these frequencies are selected based on a striation hypothesis. The linear frequency shift and corresponding phase term introduced in the array weight vector accounts for multipath-induced fading, producing beam output with increased signal gain. The method is demonstrated using data collected on an array towed in the North Atlantic. The combination of the striation-based beamformer with the waveguide invariant concept to improve tracker performance is discussed.

  2. Coordination of bat sonar activity and flight for the exploration of three-dimensional objects.

    PubMed

    Genzel, Daria; Geberl, Cornelia; Dera, Thomas; Wiegrebe, Lutz

    2012-07-01

    The unique combination of flight and echolocation has opened the nocturnal air space as a rich ecological niche for bats. By analysing echoes of their sonar emissions, bats discriminate and recognize three-dimensional (3-D) objects. However, in contrast to vision, the 3-D information that can be gained by ensonifying an object from only one observation angle is sparse. To date, it is unclear how bats synchronize echolocation and flight activity to explore the 3-D shape of ensonified objects. We have devised an experimental design that allows creating 3-D virtual echo-acoustic objects by generating in real-time echoes from the bat's emissions that depend on the bat's position relative to the virtual object. Bats were trained to evaluate these 3-D virtual objects differing in their azimuthal variation of either echo amplitude or spectral composition. The data show that through a very effective coordination of sonar and flight activity, bats analyse an azimuthal variation of echo amplitude with a resolution of approximately 16 dB and a variation of echo centre frequency of approximately 19%. Control experiments show that the bats can detect not only these variations but also perturbations in the spatial arrangement of these variations. The current experimental paradigm shows that echolocating bats assemble echo-acoustic object information - acquired sequentially in flight - to reconstruct the 3-D shape of the ensonified object. Unlike previous approaches, the recruitment of virtual objects allows for a direct quantification of this reconstruction success in a highly controlled experimental approach.

  3. 76 FR 4637 - Taking and Importing Marine Mammals; U.S. Navy's Atlantic Fleet Active Sonar Training

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-26

    ...&E) activities to be conducted within the Atlantic Fleet Active Sonar Training (AFAST) Study Area for... Integrated Comprehensive Management Program (ICMP) Plan, which is intended for use as a planning tool to... contacts listed here. The mailbox address for providing e-mail comments on the ICMP Plan is...

  4. 75 FR 5055 - Taking and Importing Marine Mammals; U.S. Navy's Atlantic Fleet Active Sonar Training (AFAST)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-01

    ... to AFAST training, maintenance, and RDT&E became effective on January 22, 2009 (74 FR 4843, January... conducted within the AFAST Study Area under regulations issued on January 22, 2009 (74 FR 4843, January 27.... Navy's Atlantic Fleet Active Sonar Training (AFAST) AGENCY: National Marine Fisheries Service...

  5. A theoretical model of linearly filtered reverberation for pulsed active sonar in shallow water.

    PubMed

    Murray, John J

    2014-11-01

    This paper presents a statistical model useful for characterizing pulsed active sonar reverberation in shallow water. The model is based on the fundamental assumption that reverberation consists of echoes from point scatterers having random positions, strengths, and Doppler dilations. Receive array beam patterns, simple propagation losses, and planar bistatic geometry are included. The probability distribution of uniformly dense scatterers as a function of echo delay and bearing is explicitly related to the change in the area from which scatterer echoes contribute to the reverberation, and is presented in closed form. The cross Q-function of the transmitted waveform and the linear filter applied to the received signal arises naturally from the development. This function, along with environmental spreading, determines the shape of the reverberation along the Doppler axis. The assumptions and simplifications under which the reverberation decouples into independent spatial (delay and bearing) and Doppler terms are presented.

  6. Discrimination of jittered sonar echoes by the echolocating bat, Eptesicus fuscus: the shape of target images in echolocation.

    PubMed

    Simmons, J A; Ferragamo, M; Moss, C F; Stevenson, S B; Altes, R A

    1990-11-01

    1. Behavioral experiments with jittering echoes examined acoustic images of sonar targets in the echolocating bat, Eptesicus fuscus, along the echo delay or target range axis. Echo phase, amplitude, bandwidth, and signal-to-noise ratio were manipulated to assess the underlying auditory processes for image formation. 2. Fine delay acuity is about 10 ns. Calibration and control procedures indicate that this represents temporal acuity rather than spectral discrimination. Jitter discrimination curves change in phase when the phase of one jittering echo is shifted by 180 degrees relative to the other, showing that echo phase is involved in delay estimation. At an echo detectability index of about 36 dB, fine acuity is 40 ns, which is approximately as predicted for the delay accuracy of an ideal receiver. 3. Compound performance curves for 0 degrees and 180 degrees phase conditions match the crosscorrelation function of the echoes. The locations of both 0 degrees and 180 degrees phase peaks in the performance curves shift along the time axis by an amount that matches neural amplitude-latency trading in Eptesicus, confirming a temporal basis for jitter discrimination.

  7. Convergence of temporal and spectral information into acoustic images of complex sonar targets perceived by the echolocating bat, Eptesicus fuscus.

    PubMed

    Simmons, J A; Moss, C F; Ferragamo, M

    1990-02-01

    1. FM echolocating bats (Eptesicus fuscus) were trained to discriminate between a two-component complex target and a one-component simple target simulated by electronically-returned echoes in a series of experiments that explore the composition of the image of the two-component target. In Experiment I, echoes for each target were presented sequentially, and the bats had to compare a stored image of one target with that of the other. The bats made errors when the range of the simple target corresponded to the range of either glint in the complex target, indicating that some trace of the parts of one image interfered with perception of the other image. In Experiment II, echoes were presented simultaneously as well as sequentially, permitting direct masking of echoes from one target to the other. Changes in echo amplitude produced shifts in apparent range whose pattern depended upon the mode of echo presentation. 2. Eptesicus perceives images of complex sonar targets that explicitly represent the location and spacing of discrete glints located at different ranges. The bat perceives the target's structure in terms of its range profile along a psychological range axis using a combination of echo delay and echo spectral representations that together resemble a spectrogram of the FM echoes. The image itself is expressed entirely along a range scale that is defined with reference to echo delay. Spectral information contributes to the image by providing estimates of the range separation of glints, but it is transformed into these estimates. 3. Perceived absolute range is encoded by the timing of neural discharges and is vulnerable to shifts caused by neural amplitude-latency trading, which was estimated at 13 to 18 microseconds per dB from N1 and N4 auditory evoked potentials in Eptesicus. Spectral cues representing the separation of glints within the target are transformed into estimates of delay separations before being incorporated into the image. However, because they

  8. Potential Population Consequences of Active Sonar Disturbance in Atlantic Herring: Estimating the Maximum Risk.

    PubMed

    Sivle, Lise Doksæter; Kvadsheim, Petter Helgevold; Ainslie, Michael

    2016-01-01

    Effects of noise on fish populations may be predicted by the population consequence of acoustic disturbance (PCAD) model. We have predicted the potential risk of population disturbance when the highest sound exposure level (SEL) at which adult herring do not respond to naval sonar (SEL(0)) is exceeded. When the population density is low (feeding), the risk is low even at high sonar source levels and long-duration exercises (>24 h). With densely packed populations (overwintering), a sonar exercise might expose the entire population to levels >SEL(0) within a 24-h exercise period. However, the disturbance will be short and the response threshold used here is highly conservative. It is therefore unlikely that naval sonar will significantly impact the herring population.

  9. Potential Population Consequences of Active Sonar Disturbance in Atlantic Herring: Estimating the Maximum Risk.

    PubMed

    Sivle, Lise Doksæter; Kvadsheim, Petter Helgevold; Ainslie, Michael

    2016-01-01

    Effects of noise on fish populations may be predicted by the population consequence of acoustic disturbance (PCAD) model. We have predicted the potential risk of population disturbance when the highest sound exposure level (SEL) at which adult herring do not respond to naval sonar (SEL(0)) is exceeded. When the population density is low (feeding), the risk is low even at high sonar source levels and long-duration exercises (>24 h). With densely packed populations (overwintering), a sonar exercise might expose the entire population to levels >SEL(0) within a 24-h exercise period. However, the disturbance will be short and the response threshold used here is highly conservative. It is therefore unlikely that naval sonar will significantly impact the herring population. PMID:26610962

  10. The effect of active sonar for the protection of moored and anchored warships on the human hearing.

    PubMed

    Salami, Angelo; Dellepiane, Massimo; Barbierato, Mauro; Freda, Pierluigi; Crippa, Barbara; Guastini, Luca; Mora, Renzo

    2010-02-01

    This study wants to show the effects of active middle frequency sonar on a selected group of Italian Navy divers. Ten male divers with normal hearing were exposed to active sonar of the Italian Navy for more than 100 exposures, each of at least 1-h duration, in the course of 6 months. Before, at the end, and six months after the end of noise exposure, we performed pure-tone audiometry, Carhart test, Peyser test, thresholds of discomfort test (TDT), tympanometry, transient evoked otoacoustic emissions (TEOAE), distortion product otoacoustic emissions (DPOAE), and auditory brainstem response (ABR). At the end of the noise exposure, the audiological tests showed a worsening of the mean air and bone audiometric thresholds at the 2,000 (1/10), 4,000 (7/10), and 8,000 Hz (6/10); a fail status of the TEOAE and DPOAE, which were previously present, in all the divers; temporary threshold shift, at the Peyser test, in 9/10 divers; discomfort for pulse tone presented at the TDT test, in all the divers; no post exposure significant differences at the Carhart and ABR tests, in any of the divers. Six months after the end of noise exposure, all the divers presented a complete recovery of their audio-vestibular functions. Our results show the temporary negative effects of repeated and lasting exposure to active sonar (Hull MF) on the divers; the last control demonstrate the absence of permanent noise-induced hearing loss in divers exposed to active sonar. PMID:19597738

  11. The effect of active sonar for the protection of moored and anchored warships on the human hearing.

    PubMed

    Salami, Angelo; Dellepiane, Massimo; Barbierato, Mauro; Freda, Pierluigi; Crippa, Barbara; Guastini, Luca; Mora, Renzo

    2010-02-01

    This study wants to show the effects of active middle frequency sonar on a selected group of Italian Navy divers. Ten male divers with normal hearing were exposed to active sonar of the Italian Navy for more than 100 exposures, each of at least 1-h duration, in the course of 6 months. Before, at the end, and six months after the end of noise exposure, we performed pure-tone audiometry, Carhart test, Peyser test, thresholds of discomfort test (TDT), tympanometry, transient evoked otoacoustic emissions (TEOAE), distortion product otoacoustic emissions (DPOAE), and auditory brainstem response (ABR). At the end of the noise exposure, the audiological tests showed a worsening of the mean air and bone audiometric thresholds at the 2,000 (1/10), 4,000 (7/10), and 8,000 Hz (6/10); a fail status of the TEOAE and DPOAE, which were previously present, in all the divers; temporary threshold shift, at the Peyser test, in 9/10 divers; discomfort for pulse tone presented at the TDT test, in all the divers; no post exposure significant differences at the Carhart and ABR tests, in any of the divers. Six months after the end of noise exposure, all the divers presented a complete recovery of their audio-vestibular functions. Our results show the temporary negative effects of repeated and lasting exposure to active sonar (Hull MF) on the divers; the last control demonstrate the absence of permanent noise-induced hearing loss in divers exposed to active sonar.

  12. Protocols for calibrating multibeam sonar.

    PubMed

    Foote, Kenneth G; Chu, Dezhang; Hammar, Terence R; Baldwin, Kenneth C; Mayer, Larry A; Hufnagle, Lawrence C; Jech, J Michael

    2005-04-01

    Development of protocols for calibrating multibeam sonar by means of the standard-target method is documented. Particular systems used in the development work included three that provide the water-column signals, namely the SIMRAD SM2000/90- and 200-kHz sonars and RESON SeaBat 8101 sonar, with operating frequency of 240 kHz. Two facilities were instrumented specifically for the work: a sea well at the Woods Hole Oceanographic Institution and a large, indoor freshwater tank at the University of New Hampshire. Methods for measuring the transfer characteristics of each sonar, with transducers attached, are described and illustrated with measurement results. The principal results, however, are the protocols themselves. These are elaborated for positioning the target, choosing the receiver gain function, quantifying the system stability, mapping the directionality in the plane of the receiving array and in the plane normal to the central axis, measuring the directionality of individual beams, and measuring the nearfield response. General preparations for calibrating multibeam sonars and a method for measuring the receiver response electronically are outlined. Advantages of multibeam sonar calibration and outstanding problems, such as that of validation of the performance of multibeam sonars as configured for use, are mentioned.

  13. Effects of surveillance towed array sensor system (SURTASS) low frequency active sonar on fish

    NASA Astrophysics Data System (ADS)

    Popper, Arthur N.; Halvorsen, Michele B.; Miller, Diane; Smith, Michael E.; Song, Jiakun; Wysocki, Lidia E.; Hastings, Mardi C.; Kane, Andrew S.; Stein, Peter

    2005-04-01

    We investigated the effects of exposure to Low Frequency Active (LFA) sonar on rainbow trout (a hearing non-specialist related to several endangered salmonids) and channel catfish (a hearing specialist), using an element of the standard SURTASS LFA source array. We measured hearing sensitivity using auditory brainstem response, effects on inner ear structure using scanning electron microscopy, effects on non-auditory tissues using general pathology and histopathology, and behavioral effects with video monitoring. Exposure to 193 dB re 1 microPa (rms received level) in the LFA frequency band for 324 seconds resulted in a TTS of 20 dB at 400 Hz in rainbow trout, with less TTS at 100 and 200 Hz. TTS in catfish ranged from 6 to 12 dB at frequencies from 200 to 1000 Hz. Both species recovered from hearing loss in several days. Inner ears sensory tissues appeared unaffected by acoustic exposure. Gross pathology indicated no damage to non-auditory tissues, including the swim bladder. Both species showed consistent startle responses at sound onsets and changed their position relative to the sound source during exposures. There was no fish death attributable to sound exposure even up to four days post-exposure. [Work supported by Chief of Naval Operations.

  14. Acoustic image representation of a point target in the bat Eptesicus fuscus: evidence for sensitivity to echo phase in bat sonar.

    PubMed

    Moss, C F; Simmons, J A

    1993-03-01

    Echolocating bats, Eptesicus fuscus, were trained in two distinct behavioral tasks to investigate the images they perceive of a sonar point target. In the first task, bats were trained in a two-alternative forced-choice procedure to detect electronically simulated target echoes at a range of approximately 57 cm. Half of the trials in the detection task contained echoes from a stationary target (simulated by a fixed echo delay) and half contained echoes from a jittering target (simulated by an echo delay alternating between two time values over successive sonar emissions). In the second task, bats were trained in a two-alternative forced-choice procedure to discriminate between electronically simulated stationary and jittering targets, centered about a range of 57 cm. Both target detection and target jitter discrimination performance were assessed as a function of jitter magnitude, with jitter values ranging from 0-60 microseconds (corresponding to a change in distance of 0 to 10.3 mm). In both detection and discrimination tasks, the bat's performance changed cyclically with the magnitude of echo jitter. Specifically, when the phase of the playback echoes was unchanged, performance levels were poorest at 0 and 30 microseconds, and when the phase of the echoes alternated by 180 deg from one to the next, performance levels were poorest at 15 and 40-50 microseconds. The results suggest that Eptesicus is sensitive to the phase reversal of echoes and thus have implications for assessing receiver models of echolocation. PMID:8473609

  15. Acoustic image representation of a point target in the bat Eptesicus fuscus: evidence for sensitivity to echo phase in bat sonar.

    PubMed

    Moss, C F; Simmons, J A

    1993-03-01

    Echolocating bats, Eptesicus fuscus, were trained in two distinct behavioral tasks to investigate the images they perceive of a sonar point target. In the first task, bats were trained in a two-alternative forced-choice procedure to detect electronically simulated target echoes at a range of approximately 57 cm. Half of the trials in the detection task contained echoes from a stationary target (simulated by a fixed echo delay) and half contained echoes from a jittering target (simulated by an echo delay alternating between two time values over successive sonar emissions). In the second task, bats were trained in a two-alternative forced-choice procedure to discriminate between electronically simulated stationary and jittering targets, centered about a range of 57 cm. Both target detection and target jitter discrimination performance were assessed as a function of jitter magnitude, with jitter values ranging from 0-60 microseconds (corresponding to a change in distance of 0 to 10.3 mm). In both detection and discrimination tasks, the bat's performance changed cyclically with the magnitude of echo jitter. Specifically, when the phase of the playback echoes was unchanged, performance levels were poorest at 0 and 30 microseconds, and when the phase of the echoes alternated by 180 deg from one to the next, performance levels were poorest at 15 and 40-50 microseconds. The results suggest that Eptesicus is sensitive to the phase reversal of echoes and thus have implications for assessing receiver models of echolocation.

  16. Target shape perception and clutter rejection use the same mechanism in bat sonar.

    PubMed

    Warnecke, Michaela; Simmons, James A

    2016-05-01

    Big brown bats (Eptesicus fuscus) emit frequency-modulated (FM) biosonar sounds containing two or more harmonic sweeps. Echoes from frontally located targets arrive with first and second harmonics intact, leading to focused delay images. Echoes from offside or distant objects arrive with the second harmonic relatively weaker (lowpass-filtered), leading to defocused images, which prevents their clutter interference effects (Bates et al. J Exp Biol 214:394-401, 2011). Realistic targets contain several glints at slightly different distances and reflect several echoes at correspondingly different delays. The bat registers the delay of the nearest glint's echoes in the time domain. The delays of echoes from the farther glints are registered in the frequency domain, from interference nulls in the spectrum. Lowpass-filtering of echoes directly affects the image of the nearest glint by defocusing the delay image. However, lowpass-filtering also is superimposed on the interference spectrum used to register the farther glints, which distorts the pattern of interference nulls, defocusing the farther glints inversely, in the spectral domain, before they are perceived as delays. Differences in blurring between time-domain and frequency-domain parts of images identifies separate computational paths to perceptually reconstruct objects and prevent interference from off-side or distant clutter. PMID:27041334

  17. Target shape perception and clutter rejection use the same mechanism in bat sonar.

    PubMed

    Warnecke, Michaela; Simmons, James A

    2016-05-01

    Big brown bats (Eptesicus fuscus) emit frequency-modulated (FM) biosonar sounds containing two or more harmonic sweeps. Echoes from frontally located targets arrive with first and second harmonics intact, leading to focused delay images. Echoes from offside or distant objects arrive with the second harmonic relatively weaker (lowpass-filtered), leading to defocused images, which prevents their clutter interference effects (Bates et al. J Exp Biol 214:394-401, 2011). Realistic targets contain several glints at slightly different distances and reflect several echoes at correspondingly different delays. The bat registers the delay of the nearest glint's echoes in the time domain. The delays of echoes from the farther glints are registered in the frequency domain, from interference nulls in the spectrum. Lowpass-filtering of echoes directly affects the image of the nearest glint by defocusing the delay image. However, lowpass-filtering also is superimposed on the interference spectrum used to register the farther glints, which distorts the pattern of interference nulls, defocusing the farther glints inversely, in the spectral domain, before they are perceived as delays. Differences in blurring between time-domain and frequency-domain parts of images identifies separate computational paths to perceptually reconstruct objects and prevent interference from off-side or distant clutter.

  18. Digitally controlled sonars

    NASA Technical Reports Server (NTRS)

    Hansen, G. R.

    1983-01-01

    Sonars are usually designed and constructed as stand alone instruments. That is, all elements or subsystems of the sonar are provided: power conditioning, displays, intercommunications, control, receiver, transmitter, and transducer. The sonars which are a part of the Advanced Ocean Test Development Platform (AOTDP) represent a departure from this manner of implementation and are configured more like an instrumentation system. Only the transducer, transmitter, and receiver which are unique to a particular sonar function; Up, Down, Side Scan, exist as separable subsystems. The remaining functions are reserved to the AOTDP and serve all sonars and other instrumentation in a shared manner. The organization and functions of the common AOTDP elements were described and then the interface with the sonars discussed. The techniques for software control of the sonar parameters were explained followed by the details of the realization of the sonar functions and some discussion of the performance of the side scan sonars.

  19. Aerial ultrasonic micro Doppler sonar detection range in outdoor environments.

    PubMed

    Bradley, Marshall; Sabatier, James M

    2012-03-01

    Current research demonstrates that micro Doppler sonar has the capability to uniquely identify the presence of a moving human, making it an attractive component in surveillance systems for border security applications. Primary environmental factors that limit sonar performance are two-way spreading losses, ultrasonic absorption, and backscattered energy from the ground that appears at zero Doppler shift in the sonar signal processor. Spectral leakage from the backscatter component has a significant effect on sonar performance for slow moving targets. Sonar performance is shown to rapidly decay as the sensor is moved closer to the ground due to increasing surface backscatter levels.

  20. Coherent-based method for detection of underwater objects from sonar imagery

    NASA Astrophysics Data System (ADS)

    Tucker, James D.; Azimi-Sadjadi, Mahmood R.; Dobeck, Gerry J.

    2007-04-01

    Detection and classification of underwater objects in sonar imagery are challenging problems. In this paper, a new coherent-based method for detecting potential targets in high-resolution sonar imagery is developed using canonical correlation analysis (CCA). Canonical coordinate decomposition allows us to quantify the changes between the returns from the bottom and any target activity in sonar images and at the same time extract useful features for subsequent classification without the need to perform separate detection and feature extraction. Moreover, in situations where any visual analysis or verification by human operators is required, the detected/classified objects can be reconstructed from the coherent features. In this paper, underwater target detection using the canonical correlations extracted from regions of interest within the sonar image is considered. Test results of the proposed method on underwater side-scan sonar images provided by the Naval Surface Warfare Center (NSWC) in Panama City, FL is presented. This database contains synthesized targets in real background varying in degree of difficulty and bottom clutter. Results illustrating the effectiveness of the CCA based detection method are presented in terms of probability of detection, and false alarm rates for various densities of background clutter.

  1. Active part of Charlie--Gibbs fracture zone: A study using sonar and other geophysical techniques

    SciTech Connect

    Searle, R.

    1981-01-10

    A short survey with Gloria side-scan sonar and other geophysical instruments has revealed new information about Charlie--Gibbs fracture zone between 29/sup 0/ and 36 /sup 0/W. The traces of two transform faults have been clearly delineated. They fit small circles about the pole of rotation with an rms error of only about 1 km, but they do not always follow the deepest parts of the transform valleys. The transforms are joined by a short spreading center at 31 /sup 0/45 'W. The median transverse ridge appears to have been produced by normal seafloor spreading at this center and bears identifiable Vine-Matthews magnetic anomalies. A transverse ridge along the eastern inactive part of the northern transform may be an intrusive feature. Considerable thickness of sediment appear to have been deposited in the northern transform valley from Norwegian Sea overflow water passing through the fracture zone, but transverse ridges have prevented the sediment reaching the southern valley.

  2. Multiband space time processing for torpedo alert sonar

    NASA Astrophysics Data System (ADS)

    Chen, Yang; Zhao, Anbang

    2013-12-01

    A space time processing technology using harmonic CW wave is introduced to enhance the detecting performance of motion target based on active towed sonar based on CW wave. The detecting ability of CW wave and harmonic CW wave in multi-path channel is analyzed comparatively. The simulation results indicate that in multi-path channel harmonic CW wave is provided with a better performance.

  3. Vocal control of acoustic information for sonar discriminations by the echolocating bat, Eptesicus fuscus.

    PubMed

    Wadsworth, J; Moss, C F

    2000-04-01

    This study aimed to determine whether bats using frequency modulated (FM) echolocation signals adapt the features of their vocalizations to the perceptual demands of a particular sonar task. Quantitative measures were obtained from the vocal signals produced by echolocating bats (Eptesicus fuscus) that were trained to perform in two distinct perceptual tasks, echo delay and Doppler-shift discriminations. In both perceptual tasks, the bats learned to discriminate electronically manipulated playback signals of their own echolocation sounds, which simulated echoes from sonar targets. Both tasks utilized a single-channel electronic target simulator and tested the bat's in a two-alternative forced choice procedure. The results of this study demonstrate changes in the features of the FM bats' sonar sounds with echolocation task demands, lending support to the notion that this animal actively controls the echo information that guides its behavior.

  4. Sonar pulse wave form optimization in cluttered environments.

    PubMed

    Weichman, Peter B

    2006-09-01

    A theory of active sonar (or radar) pulse wave form design, for optimal target detection in cluttered environments, is presented. The received target signal is maximized via a cost function L that incorporates both the signal-to-noise ratio and a generalization of the Heisenberg uncertainty principle, which is used to balance bandwidth (or range resolution) against signal gain. The optimal pulse wave form is the ground state solution to a one-dimensional Schrödinger-type equation in frequency space, with an effective potential energy that tends to concentrate pulse energy in frequency bands where the target reflectivity dominates the clutter reflectivity.

  5. Sonar pulse wave form optimization in cluttered environments

    NASA Astrophysics Data System (ADS)

    Weichman, Peter B.

    2006-09-01

    A theory of active sonar (or radar) pulse wave form design, for optimal target detection in cluttered environments, is presented. The received target signal is maximized via a cost function L that incorporates both the signal-to-noise ratio and a generalization of the Heisenberg uncertainty principle, which is used to balance bandwidth (or range resolution) against signal gain. The optimal pulse wave form is the ground state solution to a one-dimensional Schrödinger-type equation in frequency space, with an effective potential energy that tends to concentrate pulse energy in frequency bands where the target reflectivity dominates the clutter reflectivity.

  6. Introduction to Sonar, Naval Education and Training Command. Revised Edition.

    ERIC Educational Resources Information Center

    Naval Education and Training Command, Pensacola, FL.

    This Rate Training Manual (RTM) and Nonresident Career Course form a self-study package for those U.S. Navy personnel who are seeking advancement in the Sonar Technician Rating. Among the requirements of the rating are the abilities to obtain and interpret underwater data, operate and maintain upkeep of sonar equipment, and interpret target and…

  7. An autocorrelation model of bat sonar.

    PubMed

    Wiegrebe, Lutz

    2008-06-01

    Their sonar system allows echolocating bats to navigate with high skill through a complex, three- dimensional environment at high speed and low light. The auditory analysis of the echoes of their ultrasonic sounds requires a detailed comparison of the emission and echoes. Here an auditory model of bat sonar is introduced and evaluated against a set of psychophysical phantom-target, echo-acoustic experiments. The model consists of a relatively detailed simulation of auditory peripheral processing in the bat, Phyllostomus discolor, followed by a functional module consisting of a strobed, normalised, autocorrelation in each frequency channel. The model output is accumulated in a sonar image buffer. The model evaluation is based on the comparison of the image-buffer contents generated in individually simulated psychophysical trials. The model provides reasonably good predictions for both temporal and spectral behavioural sonar processing in terms of sonar delay-, roughness, and phase sensitivity and in terms of sensitivity to the temporal separations in two-front targets and the classification of spectrally divergent phantom targets.

  8. A beam based method for target localization: inspiration from bats' directivity and binaural reception for ultrasonic sonar.

    PubMed

    Guarato, Francesco; Windmill, James; Gachagan, Anthony

    2013-06-01

    The process of echolocation is accomplished by bats partly using the beam profiles associated with their ear shapes that allow for discrimination between different echo directions. Indeed, knowledge of the emitted signal characteristic and measurement of the echo travel time from a target make it possible to compensate for attenuation due to distance, and to focus on filtering through the receivers' beam profiles by comparing received echoes to the original signal at all frequencies in the spectrum of interest. From this basis, a beam profile method to localize a target in three-dimensional space for an ultrasonic sensor system equipped with an emitter and two receivers is presented. Simulations were conducted with different noise levels, and only the contribution of the receivers' beam profiles was considered to estimate the orientation of the target with respect to the receivers. The beam pattern of the Phyllostomus discolor's ear was adopted as that of a receiver. Analyses of beam resolution and frequency ranges were conducted to enhance the accuracy of orientation estimates. The choice of appropriate resolution and frequency ranges guarantee that error mean values for most of the orientations are within [0.5°, 1.5°], even in noisy situations: Signal-to-noise ratio values considered in this work are 35 and 50 dB.

  9. Effects of mid-frequency active sonar on hearing in fish.

    PubMed

    Halvorsen, Michele B; Zeddies, David G; Ellison, William T; Chicoine, David R; Popper, Arthur N

    2012-01-01

    Caged fish were exposed to sound from mid-frequency active (MFA) transducers in a 5 × 5 planar array which simulated MFA sounds at received sound pressure levels of 210 dB SPL(re 1 μPa). The exposure sound consisted of a 2 s frequency sweep from 2.8 to 3.8 kHz followed by a 1 s tone at 3.3 kHz. The sound sequence was repeated every 25 s for five repetitions resulting in a cumulative sound exposure level (SEL(cum)) of 220 dB re 1 μPa(2) s. The cumulative exposure level did not affect the hearing sensitivity of rainbow trout, a species whose hearing range is lower than the frequencies in the presented MFA sound. In contrast, one cohort of channel catfish showed a statistically significant temporary threshold shift of 4-6 dB at 2300 Hz, but not at lower tested frequencies, whereas a second cohort showed no change. It is likely that this threshold shift resulted from the frequency spectrum of the MFA sound overlapping with the upper end of the hearing frequency range of the channel catfish. The observed threshold shifts in channel catfish recovered within 24 h. There was no mortality associated with the MFA sound exposure used in this test.

  10. Imaging sonar development for mine countermeasure applications

    NASA Astrophysics Data System (ADS)

    Johnson, Bruce

    2002-05-01

    Over the past decade the Office of Naval Research (ONR) has sponsored research to improve the mine countermeasures (MCM) community's ability to detect, classify, reacquire, and identify mines. In the first stage of wide area detection and classification, the single biggest problem is the ability to distinguish mines from clutter with side-scan sonar assets. In the reacquire-identify stage, divers employ a single-beam aural sonar for guidance to close proximity for visual identification of targets. Current sonar research efforts in wide-area search focus on clutter rejection through high-resolution imaging by synthetic aperture processing and cuing from broadband response characteristics. For reacquisition and identification, research has focused on compact, multibeam imagers. ONR's focus on transition from towbodies and divers to numbers of small, unmanned underwater vehicles (UUVs) to improve MCM clearance rates has had a major impact on sensor development as well. The presentation will provide an introduction to the session by providing a brief history of the development of navy imaging sonars, how they are employed, and an overview of the current thrusts that will lead to the next generation of Navy MCM sonars.

  11. Sonar array processing borrows from geophysics

    SciTech Connect

    Chen, K.

    1989-09-01

    The author reports a recent advance in sonar signal processing that has potential military application. It improves signal extraction by modifying a technique devised by a geophysicist. Sonar signal processing is used to track submarine and surface targets, such as aircraft carriers, oil tankers, and, in commercial applications, schools of fish or sunken treasure. Similar signal-processing techniques help radio astronomers track galaxies, physicians see images of the body interior, and geophysicists map the ocean floor or find oil. This hydrid technique, applied in an experimental system, can help resolve strong signals as well as weak ones in the same step.

  12. Introduction to Sonar, Navy Training Course.

    ERIC Educational Resources Information Center

    Naval Personnel Program Support Activity, Washington, DC.

    Fundamentals of sonar systems are presented in this book, prepared for both regular navy and naval reserve personnel who are seeking advancement in rating. An introductory description is first made of submarines and antisubmarine units. Determination of underwater targets is analyzed from the background of true and relative bearings, true and…

  13. Behavioral responses by grey seals (Halichoerus grypus) to high frequency sonar.

    PubMed

    Hastie, Gordon D; Donovan, Carl; Götz, Thomas; Janik, Vincent M

    2014-02-15

    The use of high frequency sonar is now commonplace in the marine environment. Most marine mammals rely on sound to navigate, and for detecting prey, and there is the potential that the acoustic signals of sonar could cause behavioral responses. To investigate this, we carried out behavioral response tests with grey seals to two sonar systems (200 and 375 kHz systems). Results showed that both systems had significant effects on the seals behavior; when the 200 kHz sonar was active, seals spent significantly more time hauled out and, although seals remained swimming during operation of the 375 kHz sonar, they were distributed further from the sonar. The results show that although peak sonar frequencies may be above marine mammal hearing ranges, high levels of sound can be produced within their hearing ranges that elicit behavioral responses; this has clear implications for the widespread use of sonar in the marine environment.

  14. Object detection in side scan sonar

    NASA Astrophysics Data System (ADS)

    Wang, Wenwu; Cheng, Binbin; Chen, Yao

    2015-12-01

    Automatic target detection is a challenging task as the response from an underwater target may vary greatly depending on its configuration, sonar parameters and the environment. We propose a Z- test algorithm for target detection in side scan sonar image which avoids this problem that covers the variation in the target response. A Z-test is performed on the means of the pixel gray levels within and outside the window area, a detection being called when the value of test statistic feature exceeds a certain threshold. The algorithm is formulated for real-time execution on limited memory commercial-of-the-shelf platforms and is capable of detection objects on the seabed-bottom.

  15. How do tiger moths jam bat sonar?

    PubMed

    Corcoran, Aaron J; Barber, Jesse R; Hristov, Nickolay I; Conner, William E

    2011-07-15

    The tiger moth Bertholdia trigona is the only animal in nature known to defend itself by jamming the sonar of its predators - bats. In this study we analyzed the three-dimensional flight paths and echolocation behavior of big brown bats (Eptesicus fuscus) attacking B. trigona in a flight room over seven consecutive nights to determine the acoustic mechanism of the sonar-jamming defense. Three mechanisms have been proposed: (1) the phantom echo hypothesis, which states that bats misinterpret moth clicks as echoes; (2) the ranging interference hypothesis, which states that moth clicks degrade the bats' precision in determining target distance; and (3) the masking hypothesis, which states that moth clicks mask the moth echoes entirely, making the moth temporarily invisible. On nights one and two of the experiment, the bats appeared startled by the clicks; however, on nights three through seven, the bats frequently missed their prey by a distance predicted by the ranging interference hypothesis (∼15-20 cm). Three-dimensional simulations show that bats did not avoid phantom targets, and the bats' ability to track clicking prey contradicts the predictions of the masking hypothesis. The moth clicks also forced the bats to reverse their stereotyped pattern of echolocation emissions during attack, even while bats continued pursuit of the moths. This likely further hinders the bats' ability to track prey. These results have implications for the evolution of sonar jamming in tiger moths, and we suggest evolutionary pathways by which sonar jamming may have evolved from other tiger moth defense mechanisms.

  16. Spatial perception and adaptive sonar behavior.

    PubMed

    Aytekin, Murat; Mao, Beatrice; Moss, Cynthia F

    2010-12-01

    Bat echolocation is a dynamic behavior that allows for real-time adaptations in the timing and spectro-temporal design of sonar signals in response to a particular task and environment. To enable detailed, quantitative analyses of adaptive sonar behavior, echolocation call design was investigated in big brown bats, trained to rest on a stationary platform and track a tethered mealworm that approached from a starting distance of about 170 cm in the presence of a stationary sonar distracter. The distracter was presented at different angular offsets and distances from the bat. The results of this study show that the distance and the angular offset of the distracter influence sonar vocalization parameters of the big brown bat, Eptesicus fuscus. Specifically, the bat adjusted its call duration to the closer of two objects, distracter or insect target, and the magnitude of the adjustment depended on the angular offset of the distracter. In contrast, the bat consistently adjusted its call rate to the distance of the insect, even when this target was positioned behind the distracter. The results hold implications for understanding spatial information processing and perception by echolocation.

  17. Pathology: whales, sonar and decompression sickness.

    PubMed

    Piantadosi, Claude A; Thalmann, Edward D

    2004-04-15

    We do not yet know why whales occasionally strand after sonar has been deployed nearby, but such information is important for both naval undersea activities and the protection of marine mammals. Jepson et al. suggest that a peculiar gas-forming disease afflicting some stranded cetaceans could be a type of decompression sickness (DCS) resulting from exposure to mid-range sonar. However, neither decompression theory nor observation support the existence of a naturally occurring DCS in whales that is characterized by encapsulated, gas-filled cavities in the liver. Although gas-bubble formation may be aggravated by acoustic energy, more rigorous investigation is needed before sonar can be firmly linked to bubble formation in whales.

  18. Validity of the sonar equation and Babinet's principle for scattering in a stratified medium.

    PubMed

    Ratilal, Purnima; Lai, Yisan; Makris, Nicholas C

    2002-11-01

    The sonar equation rests on the assumption that received sound pressure level after scattering can be written in decibels as a sum of four terms: source level, transmission loss from the source to the target, target strength, and transmission loss from the target to the receiver. This assumption is generally not valid for scattering in a shallow water waveguide and can lead to large errors and inconsistencies in estimating a target's scattering properties as well as its limiting range of detection. By application of coherent waveguide scattering theory, the sonar equation is found to become approximately valid in a shallow water waveguide when the object's complex scatter function is roughly constant over the equivalent horizontal grazing angles +/- delta psi spanned by the dominant waveguide modes. This is approximately true (1) for all objects of spatial extent L and wavelength lambda when 2delta psisonar equation may be made valid by lowering the active frequency of operation in a waveguide. This is often desirable because it greatly simplifies the analysis necessary for target classification and localization. Similarly, conditions are given for when Babinet's principle becomes approximately valid in a shallow water waveguide.

  19. Miniature sonar fish tag

    NASA Technical Reports Server (NTRS)

    Lovelady, R. W.; Ferguson, R. L.

    1975-01-01

    Self-powered sonar device may be implanted in body of fish. It transmits signal that can be detected with portable tracking gear or by automatic detection-and-tracking system. Operating life of over 4000 hours may be expected. Device itself may be used almost indefinitely.

  20. Motion compensation on synthetic aperture sonar images

    NASA Astrophysics Data System (ADS)

    Heremans, R.; Acheroy, M.; Dupont, Y.

    2006-09-01

    High resolution sonars are required to detect and classify mines on the sea-bed. Synthetic aperture sonar increases the sonar cross range resolution by several orders of magnitudes while maintaining or increasing the area search rate. The resolution is however strongly dependent on the precision with which the motion errors of the platform can be estimated. The term micro-navigation is used to describe this very special requirement for sub-wavelength relative positioning of the platform. Therefore algorithms were designed to estimate those motion errors and to correct for them during the (ω, k)-reconstruction phase. To validate the quality of the motion estimation algorithms a single transmitter/multiple receiver simulator was build, allowing to generate multiple point targets with or without surge and/or sway and/or yaw motion errors. The surge motion estimation is shown on real data, which were taken during a sea trial in November of 2003 with the low frequency (12 kHz) side scan sonar (LFSS) moving on a rail positioned on the sea-bed near Marciana Marina on the Elba Island, Italy.

  1. Detection of buried mines with seismic sonar

    NASA Astrophysics Data System (ADS)

    Muir, Thomas G.; Baker, Steven R.; Gaghan, Frederick E.; Fitzpatrick, Sean M.; Hall, Patrick W.; Sheetz, Kraig E.; Guy, Jeremie

    2003-10-01

    Prior research on seismo-acoustic sonar for detection of buried targets [J. Acoust. Soc. Am. 103, 2333-2343 (1998)] has continued with examination of the target strengths of buried test targets as well as targets of interest, and has also examined detection and confirmatory classification of these, all using arrays of seismic sources and receivers as well as signal processing techniques to enhance target recognition. The target strengths of two test targets (one a steel gas bottle, the other an aluminum powder keg), buried in a sand beach, were examined as a function of internal mass load, to evaluate theory developed for seismic sonar target strength [J. Acoust. Soc. Am. 103, 2344-2353 (1998)]. The detection of buried naval and military targets of interest was achieved with an array of 7 shaker sources and 5, three-axis seismometers, at a range of 5 m. Vector polarization filtering was the main signal processing technique for detection. It capitalizes on the fact that the vertical and horizontal components in Rayleigh wave echoes are 90 deg out of phase, enabling complex variable processing to obtain the imaginary component of the signal power versus time, which is unique to Rayleigh waves. Gabor matrix processing of this signal component was the main technique used to determine whether the target was man-made or just a natural target in the environment. [Work sponsored by ONR.

  2. Dolphin sonar--modelling a new receiver concept.

    PubMed

    Dobbins, Peter

    2007-03-01

    Observations suggest that dolphin sonars function well in the very shallow, reverberant, near-shore region of the ocean, and significantly out-perform man-made systems under such conditions. The echolocation characteristics of many small cetaceans have been measured directly and the high performance of biosonar systems is not in question, but explanations for their resolution, target detection, localization and tracking abilities are inadequate and deserve further investigation. The dolphin's lower jaw has been identified as part of an echo-receptor, and several hypotheses have been proposed to explain this. In one of these, the regularity of dolphin teeth was considered as a sonar array. This paper explores the physics of such systems with models based on established radar and sonar principles, and using data from various dolphin species. The insights gained from this modelling then lead to speculative proposals for new sonar receiver concepts that may have advantages over more conventional designs in shallow water operation.

  3. Enhanced target versus clutter discrimination using time-frequency (LTV) filters

    NASA Astrophysics Data System (ADS)

    Gomatam, Vikram Thiruneermalai; Loughlin, Patrick

    2015-05-01

    In active sensing such as in sonar and radar, target recognition is adversely impacted by target-like returns from non-target objects (i.e. clutter). Because the target and clutter returns are in general nonstationary, the application of linear time-varying (LTV) pre-filters has been suggested to enhance target classification. We apply a minimum probability of error (MPE) classifier with and without LTV filters to distinguish targets from clutter in active sonar data. Classification performance was improved with LTV filtering.

  4. Multiple ping sonar accuracy improvement using robust motion estimation and ping fusion.

    PubMed

    Yu, Lian; Neretti, Nicola; Intrator, Nathan

    2006-04-01

    Noise degrades the accuracy of sonar systems. We demonstrate a practical method for increasing the effective signal-to-noise ratio (SNR) by fusing time delay information from a burst of multiple sonar pings. This approach can be useful when there is no relative motion between the sonar and the target during the burst of sonar pinging. Otherwise, the relative motion degrades the fusion and therefore, has to be addressed before fusion can be used. In this paper, we present a robust motion estimation algorithm which uses information from multiple receivers to estimate the relative motion between pings in the burst. We then compensate for motion, and show that the fusion of information from the burst of motion compensated pings improves both the resilience to noise and sonar accuracy, consequently increasing the operating range of the sonar system.

  5. Color and Grey Scale in Sonar Displays

    NASA Technical Reports Server (NTRS)

    Kraiss, K. F.; Kuettelwesch, K. H.

    1984-01-01

    In spite of numerous publications 1 it is still rather unclear, whether color is of any help in sonar displays. The work presented here deals with a particular type of sonar data, i.e., LOFAR-grams (low frequency analysing and recording) where acoustic sensor data are continuously written as a time-frequency plot. The question to be answered quantitatively is, whether color coding does improve target detection when compared with a grey scale code. The data show significant differences in receiver-operating characteristics performance for the selected codes. In addition it turned out, that the background noise level affects the performance dramatically for some color codes, while others remain stable or even improve. Generally valid rules are presented on how to generate useful color scales for this particular application.

  6. Phase sensitivity in bat sonar revisited.

    PubMed

    Schörnich, Sven; Wiegrebe, Lutz

    2008-01-01

    An echolocating bat produces echoes consisting of the convolution of echolocation call and the impulse response (IR) of the ensonified object. A crucial question in animal sonar is whether bats are able to extract this IR from the echo. The bat inner ear generates a frequency representation of call and echo and IR extraction in the frequency domain requires accurate analysis of both magnitude and phase information. Previous studies investigating the phase sensitivity of bats using a jitter paradigm reported a temporal acuity down to 10 ns, suggesting perfect sonar phase representation. In a phantom-target playback experiment, we investigate the perceptual phase sensitivity of the bat Phyllostomus discolor using a novel approach: instead of manipulating IR phase by changing IR delay (jitter paradigm), we randomized IR phase and thus lengthened the IR over time, leaving the magnitude spectrum unchanged. Our results show that phase sensitivity, as reflected in the analysis of signal duration, appears to be much lower than phase sensitivity, as reflected in the analysis of signal onset. The current data indicate that different temporal aspects of sonar processing are encoded with very different temporal resolution and thus an overall claim of "phase sensitivity" as such cannot be maintained.

  7. Target activation by regulatory RNAs in bacteria

    PubMed Central

    Papenfort, Kai; Vanderpool, Carin K.

    2015-01-01

    Bacterial small regulatory RNAs (sRNAs) are commonly known to repress gene expression by base pairing to target mRNAs. In many cases, sRNAs base pair with and sequester mRNA ribosome-binding sites, resulting in translational repression and accelerated transcript decay. In contrast, a growing number of examples of translational activation and mRNA stabilization by sRNAs have now been documented. A given sRNA often employs a conserved region to interact with and regulate both repressed and activated targets. However, the mechanisms underlying activation differ substantially from repression. Base pairing resulting in target activation can involve sRNA interactions with the 5′ untranslated region (UTR), the coding sequence or the 3′ UTR of the target mRNAs. Frequently, the activities of protein factors such as cellular ribonucleases and the RNA chaperone Hfq are required for activation. Bacterial sRNAs, including those that function as activators, frequently control stress response pathways or virulence-associated functions required for immediate responses to changing environments. This review aims to summarize recent advances in knowledge regarding target mRNA activation by bacterial sRNAs, highlighting the molecular mechanisms and biological relevance of regulation. PMID:25934124

  8. Ultrasonic bistatic Doppler sonar in air for personnel motion detection

    NASA Astrophysics Data System (ADS)

    Ekimov, Alexander; Hickey, Craig J.

    2012-06-01

    The National Center for Physical Acoustics (NCPA) at the University of Mississippi is working on the application of ultrasonic Doppler sonars in air for personnel motion detection. Two traditional Doppler sonar configurations, a monostatic and a bistatic, are being studied. In the monostatic configuration, the distance between the transmitter and the receiver is small. The proximity of the source to the receiver places a limitation on the system associated with the overloading of the receivers' input due to acoustic energy leakage from the transmitters' output. The maximum range of detection is therefore limited by the dynamic range of the acquisition system. In a bistatic Doppler ultrasonic sonar, the source and receiver are spaced apart and the acoustic energy along the direct path does not constrain the maximum acoustic power level output of the transmitter. In a monostatic configuration the acoustic signal suffers from beam spreading and natural absorption during propagation from the transmitter to the target and from the target back to the receiver. In a bistatic configuration the acoustic propagation is in one direction only and theoretically the detection distance can be twice the monostatic distance. For comparison the experiments of a human walking in a building hallway using the bistatic and monostaic Doppler sonars in air were conducted. The experimental results for human signatures from these Doppler sonars are presented and discussed.

  9. Tiger moth jams bat sonar.

    PubMed

    Corcoran, Aaron J; Barber, Jesse R; Conner, William E

    2009-07-17

    In response to sonar-guided attacking bats, some tiger moths make ultrasonic clicks of their own. The lepidopteran sounds have previously been shown to alert bats to some moths' toxic chemistry and also to startle bats unaccustomed to sonic prey. The moth sounds could also interfere with, or "jam," bat sonar, but evidence for such jamming has been inconclusive. Using ultrasonic recording and high-speed infrared videography of bat-moth interactions, we show that the palatable tiger moth Bertholdia trigona defends against attacking big brown bats (Eptesicus fuscus) using ultrasonic clicks that jam bat sonar. Sonar jamming extends the defensive repertoire available to prey in the long-standing evolutionary arms race between bats and insects.

  10. Security sonar for water intakes

    SciTech Connect

    Rothenbuhler, D.E.

    1987-07-01

    The security of the water approaches to nuclear facilities has been largely neglected because of the lack of solutions to the intrusion problem. This paper reviews underwater scanning sonar in general, highlights a number of problems encountered in a threat detection system using sonar and suggests some procedures that can help make such a system workable. Information is drawn from recent experience with several security projects in the governmental and private sectors, one of which was a nuclear facility.

  11. Video Guidance Sensors Using Remotely Activated Targets

    NASA Technical Reports Server (NTRS)

    Bryan, Thomas C.; Howard, Richard T.; Book, Michael L.

    2004-01-01

    Four updated video guidance sensor (VGS) systems have been proposed. As described in a previous NASA Tech Briefs article, a VGS system is an optoelectronic system that provides guidance for automated docking of two vehicles. The VGS provides relative position and attitude (6-DOF) information between the VGS and its target. In the original intended application, the two vehicles would be spacecraft, but the basic principles of design and operation of the system are applicable to aircraft, robots, objects maneuvered by cranes, or other objects that may be required to be aligned and brought together automatically or under remote control. In the first two of the four VGS systems as now proposed, the tracked vehicle would include active targets that would light up on command from the tracking vehicle, and a video camera on the tracking vehicle would be synchronized with, and would acquire images of, the active targets. The video camera would also acquire background images during the periods between target illuminations. The images would be digitized and the background images would be subtracted from the illuminated-target images. Then the position and orientation of the tracked vehicle relative to the tracking vehicle would be computed from the known geometric relationships among the positions of the targets in the image, the positions of the targets relative to each other and to the rest of the tracked vehicle, and the position and orientation of the video camera relative to the rest of the tracking vehicle. The major difference between the first two proposed systems and prior active-target VGS systems lies in the techniques for synchronizing the flashing of the active targets with the digitization and processing of image data. In the prior active-target VGS systems, synchronization was effected, variously, by use of either a wire connection or the Global Positioning System (GPS). In three of the proposed VGS systems, the synchronizing signal would be generated on, and

  12. Quantification of a multibeam sonar for fisheries assessment applications

    NASA Astrophysics Data System (ADS)

    Cochrane, N. A.; Li, Y.; Melvin, G. D.

    2003-08-01

    The acoustic theory is developed for a multibeam fisheries-type sonar employing a circular arc of transducer elements. Specifically, numerical relations for transmit and receive beam patterns are derived and methodologies set forth for the derivation of appropriately scaled acoustic target strength and acoustic volume backscattering strength from an ideally performing multibeam device. Predicted and measured beam characteristics of a realizable multibeam sonar, a Kongsberg Simrad-Mesotech SM 2000, are compared. Practical techniques for the extraction of calibrated acoustic volume backscattering strength from real systems are advanced.

  13. Quantification of a multibeam sonar for fisheries assessment applications.

    PubMed

    Cochrane, N A; Li, Y; Melvin, G D

    2003-08-01

    The acoustic theory is developed for a multibeam fisheries-type sonar employing a circular arc of transducer elements. Specifically, numerical relations for transmit and receive beam patterns are derived and methodologies set forth for the derivation of appropriately scaled acoustic target strength and acoustic volume backscattering strength from an ideally performing multibeam device. Predicted and measured beam characteristics of a realizable multibeam sonar, a Kongsberg Simrad-Mesotech SM 2000, are compared. Practical techniques for the extraction of calibrated acoustic volume backscattering strength from real systems are advanced.

  14. Perception of echo phase information in bat sonar.

    PubMed

    Simmons, J A

    1979-06-22

    Echolocating bats (Eptesicus fuscus) can detect changes as small as 500 nanoseconds in the arrival time of sonar echoes when these changes appear as jitter or alternations in arrival time from one echo to the next. The psychophysical function relating the bat's performance to the magnitude of the jitter corresponds to the half-wave rectified cross-correlation function between the emitted sonar signals and the echoes. The bat perceives the phase or period structure of the sounds, which cover the 25- to 100-kilohertz frequency range, as these are represented in the auditory system after peripheral transformation. The acoustic image of a sonar target is apparently derived from time-domain or periodicity information processing by the nervous system.

  15. Multiresolution 3-D reconstruction from side-scan sonar images.

    PubMed

    Coiras, Enrique; Petillot, Yvan; Lane, David M

    2007-02-01

    In this paper, a new method for the estimation of seabed elevation maps from side-scan sonar images is presented. The side-scan image formation process is represented by a Lambertian diffuse model, which is then inverted by a multiresolution optimization procedure inspired by expectation-maximization to account for the characteristics of the imaged seafloor region. On convergence of the model, approximations for seabed reflectivity, side-scan beam pattern, and seabed altitude are obtained. The performance of the system is evaluated against a real structure of known dimensions. Reconstruction results for images acquired by different sonar sensors are presented. Applications to augmented reality for the simulation of targets in sonar imagery are also discussed.

  16. Range compensation for backscattering measurements in the difference-frequency nearfield of a parametric sonar.

    PubMed

    Foote, Kenneth G

    2012-05-01

    Measurement of acoustic backscattering properties of targets requires removal of the range dependence of echoes. This process is called range compensation. For conventional sonars making measurements in the transducer farfield, the compensation removes effects of geometrical spreading and absorption. For parametric sonars consisting of a parametric acoustic transmitter and a conventional-sonar receiver, two additional range dependences require compensation when making measurements in the nonlinearly generated difference-frequency nearfield: an apparently increasing source level and a changing beamwidth. General expressions are derived for range compensation functions in the difference-frequency nearfield of parametric sonars. These are evaluated numerically for a parametric sonar whose difference-frequency band, effectively 1-6 kHz, is being used to observe Atlantic herring (Clupea harengus) in situ. Range compensation functions for this sonar are compared with corresponding functions for conventional sonars for the cases of single and multiple scatterers. Dependences of these range compensation functions on the parametric sonar transducer shape, size, acoustic power density, and hydrography are investigated. Parametric range compensation functions, when applied with calibration data, will enable difference-frequency echoes to be expressed in physical units of volume backscattering, and backscattering spectra, including fish-swimbladder-resonances, to be analyzed.

  17. Calibration sphere for low-frequency parametric sonars.

    PubMed

    Foote, Kenneth G; Francis, David T I; Atkins, Philip R

    2007-03-01

    The problem of calibrating parametric sonar systems at low difference frequencies used in backscattering applications is addressed. A particular parametric sonar is considered: the Simrad TOPAS PS18 Parametric Sub-bottom Profiler. This generates difference-frequency signals in the band 0.5-6 kHz. A standard target is specified according to optimization conditions based on maximizing the target strength consistent with the target strength being independent of orientation and the target being physically manageable. The second condition is expressed as the target having an immersion weight less than 200 N. The result is a 280-mm-diam sphere of aluminum. Its target strength varies from -43.4 dB at 0.5 kHz to -20.2 dB at 6 kHz. Maximum excursions in target strength over the frequency band due to uncertainty in material properties of the sphere are of order +/-0.1 dB. Maximum excursions in target strength due to variations in mass density and sound speed of the immersion medium are larger, but can be eliminated by attention to the hydrographic conditions. The results are also applicable to the standard-target calibration of conventional sonars operating at low-kilohertz frequencies.

  18. Bats coordinate sonar and flight behavior as they forage in open and cluttered environments.

    PubMed

    Falk, Benjamin; Jakobsen, Lasse; Surlykke, Annemarie; Moss, Cynthia F

    2014-12-15

    Echolocating bats use active sensing as they emit sounds and listen to the returning echoes to probe their environment for navigation, obstacle avoidance and pursuit of prey. The sensing behavior of bats includes the planning of 3D spatial trajectory paths, which are guided by echo information. In this study, we examined the relationship between active sonar sampling and flight motor output as bats changed environments from open space to an artificial forest in a laboratory flight room. Using high-speed video and audio recordings, we reconstructed and analyzed 3D flight trajectories, sonar beam aim and acoustic sonar emission patterns as the bats captured prey. We found that big brown bats adjusted their sonar call structure, temporal patterning and flight speed in response to environmental change. The sonar beam aim of the bats predicted the flight turn rate in both the open room and the forest. However, the relationship between sonar beam aim and turn rate changed in the forest during the final stage of prey pursuit, during which the bat made shallower turns. We found flight stereotypy developed over multiple days in the forest, but did not find evidence for a reduction in active sonar sampling with experience. The temporal patterning of sonar sound groups was related to path planning around obstacles in the forest. Together, these results contribute to our understanding of how bats coordinate echolocation and flight behavior to represent and navigate their environment. PMID:25394632

  19. Bats coordinate sonar and flight behavior as they forage in open and cluttered environments.

    PubMed

    Falk, Benjamin; Jakobsen, Lasse; Surlykke, Annemarie; Moss, Cynthia F

    2014-12-15

    Echolocating bats use active sensing as they emit sounds and listen to the returning echoes to probe their environment for navigation, obstacle avoidance and pursuit of prey. The sensing behavior of bats includes the planning of 3D spatial trajectory paths, which are guided by echo information. In this study, we examined the relationship between active sonar sampling and flight motor output as bats changed environments from open space to an artificial forest in a laboratory flight room. Using high-speed video and audio recordings, we reconstructed and analyzed 3D flight trajectories, sonar beam aim and acoustic sonar emission patterns as the bats captured prey. We found that big brown bats adjusted their sonar call structure, temporal patterning and flight speed in response to environmental change. The sonar beam aim of the bats predicted the flight turn rate in both the open room and the forest. However, the relationship between sonar beam aim and turn rate changed in the forest during the final stage of prey pursuit, during which the bat made shallower turns. We found flight stereotypy developed over multiple days in the forest, but did not find evidence for a reduction in active sonar sampling with experience. The temporal patterning of sonar sound groups was related to path planning around obstacles in the forest. Together, these results contribute to our understanding of how bats coordinate echolocation and flight behavior to represent and navigate their environment.

  20. Bats coordinate sonar and flight behavior as they forage in open and cluttered environments

    PubMed Central

    Falk, Benjamin; Jakobsen, Lasse; Surlykke, Annemarie; Moss, Cynthia F.

    2014-01-01

    Echolocating bats use active sensing as they emit sounds and listen to the returning echoes to probe their environment for navigation, obstacle avoidance and pursuit of prey. The sensing behavior of bats includes the planning of 3D spatial trajectory paths, which are guided by echo information. In this study, we examined the relationship between active sonar sampling and flight motor output as bats changed environments from open space to an artificial forest in a laboratory flight room. Using high-speed video and audio recordings, we reconstructed and analyzed 3D flight trajectories, sonar beam aim and acoustic sonar emission patterns as the bats captured prey. We found that big brown bats adjusted their sonar call structure, temporal patterning and flight speed in response to environmental change. The sonar beam aim of the bats predicted the flight turn rate in both the open room and the forest. However, the relationship between sonar beam aim and turn rate changed in the forest during the final stage of prey pursuit, during which the bat made shallower turns. We found flight stereotypy developed over multiple days in the forest, but did not find evidence for a reduction in active sonar sampling with experience. The temporal patterning of sonar sound groups was related to path planning around obstacles in the forest. Together, these results contribute to our understanding of how bats coordinate echolocation and flight behavior to represent and navigate their environment. PMID:25394632

  1. Sonar equations for planetary exploration.

    PubMed

    Ainslie, Michael A; Leighton, Timothy G

    2016-08-01

    The set of formulations commonly known as "the sonar equations" have for many decades been used to quantify the performance of sonar systems in terms of their ability to detect and localize objects submerged in seawater. The efficacy of the sonar equations, with individual terms evaluated in decibels, is well established in Earth's oceans. The sonar equations have been used in the past for missions to other planets and moons in the solar system, for which they are shown to be less suitable. While it would be preferable to undertake high-fidelity acoustical calculations to support planning, execution, and interpretation of acoustic data from planetary probes, to avoid possible errors for planned missions to such extraterrestrial bodies in future, doing so requires awareness of the pitfalls pointed out in this paper. There is a need to reexamine the assumptions, practices, and calibrations that work well for Earth to ensure that the sonar equations can be accurately applied in combination with the decibel to extraterrestrial scenarios. Examples are given for icy oceans such as exist on Europa and Ganymede, Titan's hydrocarbon lakes, and for the gaseous atmospheres of (for example) Jupiter and Venus.

  2. Sonar equations for planetary exploration.

    PubMed

    Ainslie, Michael A; Leighton, Timothy G

    2016-08-01

    The set of formulations commonly known as "the sonar equations" have for many decades been used to quantify the performance of sonar systems in terms of their ability to detect and localize objects submerged in seawater. The efficacy of the sonar equations, with individual terms evaluated in decibels, is well established in Earth's oceans. The sonar equations have been used in the past for missions to other planets and moons in the solar system, for which they are shown to be less suitable. While it would be preferable to undertake high-fidelity acoustical calculations to support planning, execution, and interpretation of acoustic data from planetary probes, to avoid possible errors for planned missions to such extraterrestrial bodies in future, doing so requires awareness of the pitfalls pointed out in this paper. There is a need to reexamine the assumptions, practices, and calibrations that work well for Earth to ensure that the sonar equations can be accurately applied in combination with the decibel to extraterrestrial scenarios. Examples are given for icy oceans such as exist on Europa and Ganymede, Titan's hydrocarbon lakes, and for the gaseous atmospheres of (for example) Jupiter and Venus. PMID:27586766

  3. Mobile robot localization using sonar.

    PubMed

    Drumheller, M

    1987-02-01

    This correspondence describes a method by which range data from a sonar rangefinder can be used to determine the two-dimensional position and orientation of a mobile robot inside a room. The plan of the room is modeled as a list of segments indicating the positions of walls. The algorithm works by correlating straight segments in the range data against the room model, then eliminating implausible configurations using the sonar barrier test, which exploits physical constraints on sonar data. The approach is extremely tolerant of noise and clutter. Transient objects such as furniture and people need not be included in the room model, and very noisy, low-resolution sensors can be used. The algorithm's performance is demonstrated using a Polaroid Ultrasonic Rangefinder.

  4. Subsea Target Measurement Technique of High Resolution Multi-Beam Sonar System -A Case Study of Ocean Oil & Gas Production Platform and Pipeline Detection

    NASA Astrophysics Data System (ADS)

    Ding, J.; Tang, Q.; Zhou, X.

    2015-12-01

    Abstract: with fast development of modern science and technology, subsea pipeline detection means have been increasingly improved which have not only improved detection efficiency, but also extremely advanced the detection precision. The article has integrated the performance characteristics of high resolution multi-beam measurement system in recent years, which has introduced the relevant technique and detection achievement of subsea pipeline detecting (especially for exposed pipeline) by detection cases. The final detection result has been verified that high resolution multi-beam measurement system could accurately detect subsea minisize target object, which has provided the technical reference with popularization and application of new characteristics.

  5. Designing an Active Target Test Projection Chamber

    NASA Astrophysics Data System (ADS)

    Koci, James; Tan Ahn Collaboration, Dr.; Nicolas Dixneuf Collaboration

    2015-10-01

    The development of instrumentation in nuclear physics is crucial for advancing our ability to measure the properties of exotic nuclei. One limitation of the use of exotic nuclei in experiment is their very low production intensities. Recently, detectors, called active-target dectectors, have been developed to address this issue. Active-target detectors use a gas medium to image charged-particle tracks that are emitted in nuclear reactions. Last semester, I designed a vacuum chamber to be used in developing Micro-Pattern Gas detectors that will upgrade the capabilities of an active-target detector called the Prototype AT-TPC. With the exterior of the chamber complete, I have now been using an electric field modeling program, Garfield, developed by CERN to design a field cage to be placed within the vacuum chamber. The field cage will be a box-like apparatus consisting of two parallel metal plates connected with a resistor chain and attached to wires wrapped between them. The cage will provide a uniform electric field within the chamber to drift electrons from nuclear reactions down to the detector in the bottom of the chamber. These signals are then amplified by a proportional counter, and the data is sent to a computer. For the long term, we would like to incorporate a Micro-Pattern Gas Detectors in the interior of the chamber and eventually use the AT-TPC to examine various nuclei. Dr. Ahn is my advising professor.

  6. Field trial of a Doppler sonar system for fisheries applications

    NASA Astrophysics Data System (ADS)

    Tollefsen, Cristina D. S.; Zedel, Len

    2003-10-01

    Various deployments of commercial Doppler current profiling systems have demonstrated that these instruments can detect fish and measure their swimming speeds. However, research into the possible application of Doppler sonar to fisheries problems is limited and has not taken advantage of coherent signal processing schemes. A field trial was undertaken in August 2002 to explore the capabilities of a coherent Doppler sonar when applied to detecting discrete targets. The passage of migrating salmon on the Fraser River in British Columbia provided an ideal test opportunity with fish of well-defined swimming behavior and allowed for comparisons with conventional fisheries acoustics techniques. The instrument tested was a 250-kHz sonar which provided for phase coding of transmit pulses and coherent sampling of successive acoustic returns. The field trial resulted in 11 consecutive days of Doppler sonar data acquired during the peak of the sockeye salmon (Oncorhynchus nerka) migration. A total of 7425 individual fish were identified and their swimming speed was measured with an accuracy of between 10 cms-1 and 20 cms-1, which depended on pulse length, pulse spacing, and target range. By comparison, water velocity measurements made with the same instrument can only achieve a theoretical accuracy of 60 cms-1.

  7. AGU Sonar Data Restriction Panel

    NASA Astrophysics Data System (ADS)

    The AGU Council accepted the report of the panel set up in February to study the issue of restriction by the U.S. Navy of access to high-resolution sonar data for the U.S. Exclusive Economic Zone. Panel chairman John Bossier announced that “the Navy has acted in the best interests of the nation” in lifting the restriction order. Only two areas, egress routes to two submarine bases (see “Navy Defines Areas Under Sonar Ban,” in News, this issue), remain restricted.Panel members were Bruce Douglas, Alexander Malahoff, Donald Piepgras, Paul Richards, David Smith and Manik Talwani.

  8. Gray whale target strength measurements and the analysis of the backscattered response.

    PubMed

    Lucifredi, Irena; Stein, Peter J

    2007-03-01

    One of the current Integrated Marine Mammal Monitoring and Protection System (IMPAS) directions is concentrated on the design and development of the active sonar modality representing just one component of the global system. The active sonar was designed, built, and tested during the Marine Mammal Active Sonar Test (MAST 04), producing whale detections and whale tracks. The experiment was conducted in January 2004 off the coast of California. One of the objectives of the current work is to distinguish whale backscattered responses from the ones generated by the environmental clutter in a waveguide. Furthermore, the work aims to identify and analyze the target signature features that are necessary for enhanced active sonar detection and classification of marine mammals. Over the years there have been very few documented attempts to capture and analyze the backscattering response of whales using an active sonar system. Nevertheless, whales, mostly owing to their size, their motion, and the aspect dependence of their backscattered field, possess desirable properties that help distinguish their scattered response from clutter and other environment related false alarms. As an initial step, data collected during the MAST 04 experiment are presented, and gray whale target strength measurements are obtained. Results are compared to the previously published whale target strengths. Additionally, an investigation is conducted in an effort to provide whale feature identification points suitable for automated detection and classification, as means of relating gray whale active acoustic signatures to their inherent characteristics and their motion.

  9. Targeting the Channel Activity of Viroporins.

    PubMed

    To, Janet; Surya, Wahyu; Torres, Jaume

    2016-01-01

    Since the discovery that certain small viral membrane proteins, collectively termed as viroporins, can permeabilize host cellular membranes and also behave as ion channels, attempts have been made to link this feature to specific biological roles. In parallel, most viroporins identified so far are virulence factors, and interest has focused toward the discovery of channel inhibitors that would have a therapeutic effect, or be used as research tools to understand the biological roles of viroporin ion channel activity. However, this paradigm is being shifted by the difficulties inherent to small viral membrane proteins, and by the realization that protein-protein interactions and other diverse roles in the virus life cycle may represent an equal, if not, more important target. Therefore, although targeting the channel activity of viroporins can probably be therapeutically useful in some cases, the focus may shift to their other functions in following years. Small-molecule inhibitors have been mostly developed against the influenza A M2 (IAV M2 or AM2). This is not surprising since AM2 is the best characterized viroporin to date, with a well-established biological role in viral pathogenesis combined the most extensive structural investigations conducted, and has emerged as a validated drug target. For other viroporins, these studies are still mostly in their infancy, and together with those for AM2, are the subject of the present review.

  10. Limpet mine imaging sonar (LIMIS)

    NASA Astrophysics Data System (ADS)

    Belcher, Edward O.; Dinh, Hien Q.

    1999-07-01

    When divers search for limpet mines on ship hulls in turbid or dark water, they must resort to tactile examination. Acoustic systems that detect objects in turbid water typically suffer from low resolution, a low image refresh rate, a large size, and/or high power consumption. This paper discusses the design, fabrication, and testing of a small, prototype diver-held sonar that generates near- photographic quality images at a fast frame rate. Its weight in air is 7.7 kg, and it is 100 g buoyant in seawater. It is 18 cm wide, 20 cm high, and 35 cm long, including a 10-cm handle. The sonar sues acoustic lenses made from polymethylpentene to form 64 beams, each of which has a beamwidth of 0.3 degrees yielding a 1.6 cm cross-range resolution at 3-m range. The sector display has a 19.2 degree field of view. The frame rate varies with range, going from 5.5 frame/s at 15 m to 12.5 frames/s at ranges less than 4 m. The sonar consumes 25 W. The internal batteries provide 3 hours of operation between charges. External packs and cabled power provide additional power options. The images are seen on a mask-mounted video display and can also be cabled topside to a video monitor. The sonar operates at 2 MHz and has a maximum range of 15 m. This sonar allows divers to sweep hulls more efficiency and with greater safety than possible with current methods.

  11. Statistically normalized coherent change detection for synthetic aperture sonar imagery

    NASA Astrophysics Data System (ADS)

    G-Michael, Tesfaye; Tucker, J. D.; Roberts, Rodney G.

    2016-05-01

    Coherent Change Detection (CCD) is a process of highlighting an area of activity in scenes (seafloor) under survey and generated from pairs of synthetic aperture sonar (SAS) images of approximately the same location observed at two different time instances. The problem of CCD and subsequent anomaly feature extraction/detection is complicated due to several factors such as the presence of random speckle pattern in the images, changing environmental conditions, and platform instabilities. These complications make the detection of weak target activities even more difficult. Typically, the degree of similarity between two images measured at each pixel locations is the coherence between the complex pixel values in the two images. Higher coherence indicates little change in the scene represented by the pixel and lower coherence indicates change activity in the scene. Such coherence estimation scheme based on the pixel intensity correlation is an ad-hoc procedure where the effectiveness of the change detection is determined by the choice of threshold which can lead to high false alarm rates. In this paper, we propose a novel approach for anomalous change pattern detection using the statistical normalized coherence and multi-pass coherent processing. This method may be used to mitigate shadows by reducing the false alarms resulting in the coherent map due to speckles and shadows. Test results of the proposed methods on a data set of SAS images will be presented, illustrating the effectiveness of the normalized coherence in terms statistics from multi-pass survey of the same scene.

  12. Sonar sound groups and increased terminal buzz duration reflect task complexity in hunting bats

    PubMed Central

    Hulgard, Katrine; Ratcliffe, John M.

    2016-01-01

    More difficult tasks are generally regarded as such because they demand greater attention. Echolocators provide rare insight into this relationship because biosonar signals can be monitored. Here we show that bats produce longer terminal buzzes and more sonar sound groups during their approach to prey under presumably more difficult conditions. Specifically, we found Daubenton’s bats, Myotis daubentonii, produced longer buzzes when aerial-hawking versus water-trawling prey, but that bats taking revolving air- and water-borne prey produced more sonar sound groups than did the bats when taking stationary prey. Buzz duration and sonar sound groups have been suggested to be independent means by which bats attend to would-be targets and other objects of interest. We suggest that for attacking bats both should be considered as indicators of task difficulty and that the buzz is, essentially, an extended sonar sound group. PMID:26857019

  13. Sonar sound groups and increased terminal buzz duration reflect task complexity in hunting bats.

    PubMed

    Hulgard, Katrine; Ratcliffe, John M

    2016-01-01

    More difficult tasks are generally regarded as such because they demand greater attention. Echolocators provide rare insight into this relationship because biosonar signals can be monitored. Here we show that bats produce longer terminal buzzes and more sonar sound groups during their approach to prey under presumably more difficult conditions. Specifically, we found Daubenton's bats, Myotis daubentonii, produced longer buzzes when aerial-hawking versus water-trawling prey, but that bats taking revolving air- and water-borne prey produced more sonar sound groups than did the bats when taking stationary prey. Buzz duration and sonar sound groups have been suggested to be independent means by which bats attend to would-be targets and other objects of interest. We suggest that for attacking bats both should be considered as indicators of task difficulty and that the buzz is, essentially, an extended sonar sound group. PMID:26857019

  14. Sonar sound groups and increased terminal buzz duration reflect task complexity in hunting bats.

    PubMed

    Hulgard, Katrine; Ratcliffe, John M

    2016-01-01

    More difficult tasks are generally regarded as such because they demand greater attention. Echolocators provide rare insight into this relationship because biosonar signals can be monitored. Here we show that bats produce longer terminal buzzes and more sonar sound groups during their approach to prey under presumably more difficult conditions. Specifically, we found Daubenton's bats, Myotis daubentonii, produced longer buzzes when aerial-hawking versus water-trawling prey, but that bats taking revolving air- and water-borne prey produced more sonar sound groups than did the bats when taking stationary prey. Buzz duration and sonar sound groups have been suggested to be independent means by which bats attend to would-be targets and other objects of interest. We suggest that for attacking bats both should be considered as indicators of task difficulty and that the buzz is, essentially, an extended sonar sound group.

  15. Place recognition using batlike sonar.

    PubMed

    Vanderelst, Dieter; Steckel, Jan; Boen, Andre; Peremans, Herbert; Holderied, Marc W

    2016-01-01

    Echolocating bats have excellent spatial memory and are able to navigate to salient locations using bio-sonar. Navigating and route-following require animals to recognize places. Currently, it is mostly unknown how bats recognize places using echolocation. In this paper, we propose template based place recognition might underlie sonar-based navigation in bats. Under this hypothesis, bats recognize places by remembering their echo signature - rather than their 3D layout. Using a large body of ensonification data collected in three different habitats, we test the viability of this hypothesis assessing two critical properties of the proposed echo signatures: (1) they can be uniquely classified and (2) they vary continuously across space. Based on the results presented, we conclude that the proposed echo signatures satisfy both criteria. We discuss how these two properties of the echo signatures can support navigation and building a cognitive map. PMID:27481189

  16. Place recognition using batlike sonar.

    PubMed

    Vanderelst, Dieter; Steckel, Jan; Boen, Andre; Peremans, Herbert; Holderied, Marc W

    2016-01-01

    Echolocating bats have excellent spatial memory and are able to navigate to salient locations using bio-sonar. Navigating and route-following require animals to recognize places. Currently, it is mostly unknown how bats recognize places using echolocation. In this paper, we propose template based place recognition might underlie sonar-based navigation in bats. Under this hypothesis, bats recognize places by remembering their echo signature - rather than their 3D layout. Using a large body of ensonification data collected in three different habitats, we test the viability of this hypothesis assessing two critical properties of the proposed echo signatures: (1) they can be uniquely classified and (2) they vary continuously across space. Based on the results presented, we conclude that the proposed echo signatures satisfy both criteria. We discuss how these two properties of the echo signatures can support navigation and building a cognitive map.

  17. Quantifying seabed properties in shelf waters using a parametric sonar

    NASA Astrophysics Data System (ADS)

    Hines, Paul C.

    1999-12-01

    Defence Research Establishment Atlantic is developing a bottom-tethered, wide-band sonar for collecting acoustic data in the open ocean. The transmitter, a parametric array, offers three advantages: a wide bandwidth (1-10 kHz), a narrow beamwidth (icons/Journals/Common/approx" ALT="approx" ALIGN="TOP"/>3°) and virtually no sidelobes. These features allow direct measurement of seabed parameters in shallow water. Direct in this context means the absence of complications resulting from unwanted interactions of the acoustic pulse with ocean boundaries. This makes the parametric sonar an ideal tool with which to interrogate the seabed in shelf waters and quantify several geo-acoustic properties. To complement the narrow-beam active sonar, a six-channel superdirective/intensity array has been developed for the receiver. The superdirective receiver obtains a significantly narrower beam for a given array aperture than that obtained using a conventional acoustic receiver. A 900 MHz rf command link is used to steer the array to any combination of azimuth and tilt angle. Together with control over azimuth and tilt angle, the sonar frame is instrumented to monitor depth, roll and vertical acceleration to ensure quality control of the data. Data transmission back to the ship is accomplished via a 2.3 GHz rf data link capable of a data-transfer rate of up to 8 Mbits s-1. This paper describes the system's technical functionality, its acoustic principles of operation and its measurement application.

  18. Vocal premotor activity in the superior colliculus.

    PubMed

    Sinha, Shiva R; Moss, Cynthia F

    2007-01-01

    Chronic neural recordings were taken from the midbrain superior colliculus (SC) of echolocating bats while they were engaged in one of two distinct behavioral tasks: virtual target amplitude discrimination (VTAD) and real oscillating target tracking (ROTT). In the VTAD task, bats used a limited range of sonar call features to discriminate the amplitude category of echoes, whereas in the ROTT task, the bat produced dynamically modulated sonar calls to track a moving target. Newly developed methods for chronic recordings in unrestrained, behaving bats reveal two consistent bouts of SC neural activity preceding the onset of sonar vocalizations in both tasks. A short lead bout occurs tightly coupled to vocal onset (VTAD, -5.1 to -2.2 ms range, -3.6 +/- 0.7 ms mean lead time; ROTT, -3.0 to + 0.4 ms range, -1.2 +/- 1.3 ms mean lead time), and this activity may play a role in marking the time of each sonar emission. A long lead bout in SC activity occurs earlier and spreads over a longer interval (VTAD, -40.6 to -8.4 ms range, -22.2 +/- 3.9 ms mean lead time; ROTT, -29.8 to -7.1 ms range, -17.5 +/- 9.1 ms mean lead time) when compared with short lead events. In the goal-directed ROTT task, the timing of long lead event times vary with the bat's sonar call duration. This finding, along with behavioral studies demonstrating that bats adjust sonar call duration as they track targets at changing distance, suggests the bat SC contributes to range-dependent adjustments of sonar call duration. PMID:17202477

  19. Vocal premotor activity in the superior colliculus.

    PubMed

    Sinha, Shiva R; Moss, Cynthia F

    2007-01-01

    Chronic neural recordings were taken from the midbrain superior colliculus (SC) of echolocating bats while they were engaged in one of two distinct behavioral tasks: virtual target amplitude discrimination (VTAD) and real oscillating target tracking (ROTT). In the VTAD task, bats used a limited range of sonar call features to discriminate the amplitude category of echoes, whereas in the ROTT task, the bat produced dynamically modulated sonar calls to track a moving target. Newly developed methods for chronic recordings in unrestrained, behaving bats reveal two consistent bouts of SC neural activity preceding the onset of sonar vocalizations in both tasks. A short lead bout occurs tightly coupled to vocal onset (VTAD, -5.1 to -2.2 ms range, -3.6 +/- 0.7 ms mean lead time; ROTT, -3.0 to + 0.4 ms range, -1.2 +/- 1.3 ms mean lead time), and this activity may play a role in marking the time of each sonar emission. A long lead bout in SC activity occurs earlier and spreads over a longer interval (VTAD, -40.6 to -8.4 ms range, -22.2 +/- 3.9 ms mean lead time; ROTT, -29.8 to -7.1 ms range, -17.5 +/- 9.1 ms mean lead time) when compared with short lead events. In the goal-directed ROTT task, the timing of long lead event times vary with the bat's sonar call duration. This finding, along with behavioral studies demonstrating that bats adjust sonar call duration as they track targets at changing distance, suggests the bat SC contributes to range-dependent adjustments of sonar call duration.

  20. Cognitive Adaptation of Sonar Gain Control in the Bottlenose Dolphin

    PubMed Central

    Kloepper, Laura N.; Smith, Adam B.; Nachtigall, Paul E.; Buck, John R.; Simmons, James A.; Pacini, Aude F.

    2014-01-01

    Echolocating animals adjust the transmit intensity and receive sensitivity of their sonar in order to regulate the sensation level of their echoes; this process is often termed automatic gain control. Gain control is considered not to be under the animal's cognitive control, but previous investigations studied animals ensonifying targets or hydrophone arrays at predictable distances. To test whether animals maintain gain control at a fixed level in uncertain conditions, we measured changes in signal intensity for a bottlenose dolphin (Tursiops truncatus) detecting a target at three target distances (2.5, 4 and 7 m) in two types of sessions: predictable and unpredictable. Predictable sessions presented the target at a constant distance; unpredictable sessions moved the target randomly between the three target positions. In the predictable sessions the dolphin demonstrated intensity distance compensation, increasing the emitted click intensity as the target distance increased. Additionally, as trials within sessions progressed, the animal adjusted its click intensity even from the first click in a click train, which is consistent with the animal expecting a target at a certain range. In the unpredictable sessions there was no significant difference of intensity with target distance until after the 7th click in a click train. Together, these results demonstrate that the bottlenose dolphin uses learning and expectation for sonar gain control. PMID:25153530

  1. Cognitive adaptation of sonar gain control in the bottlenose dolphin.

    PubMed

    Kloepper, Laura N; Smith, Adam B; Nachtigall, Paul E; Buck, John R; Simmons, James A; Pacini, Aude F

    2014-01-01

    Echolocating animals adjust the transmit intensity and receive sensitivity of their sonar in order to regulate the sensation level of their echoes; this process is often termed automatic gain control. Gain control is considered not to be under the animal's cognitive control, but previous investigations studied animals ensonifying targets or hydrophone arrays at predictable distances. To test whether animals maintain gain control at a fixed level in uncertain conditions, we measured changes in signal intensity for a bottlenose dolphin (Tursiops truncatus) detecting a target at three target distances (2.5, 4 and 7 m) in two types of sessions: predictable and unpredictable. Predictable sessions presented the target at a constant distance; unpredictable sessions moved the target randomly between the three target positions. In the predictable sessions the dolphin demonstrated intensity distance compensation, increasing the emitted click intensity as the target distance increased. Additionally, as trials within sessions progressed, the animal adjusted its click intensity even from the first click in a click train, which is consistent with the animal expecting a target at a certain range. In the unpredictable sessions there was no significant difference of intensity with target distance until after the 7th click in a click train. Together, these results demonstrate that the bottlenose dolphin uses learning and expectation for sonar gain control.

  2. Minehunting sonar system research and development

    NASA Astrophysics Data System (ADS)

    Ferguson, Brian

    2002-05-01

    Sea mines have the potential to threaten the freedom of the seas by disrupting maritime trade and restricting the freedom of maneuver of navies. The acoustic detection, localization, and classification of sea mines involves a sequence of operations starting with the transmission of a sonar pulse and ending with an operator interpreting the information on a sonar display. A recent improvement to the process stems from the application of neural networks to the computed aided detection of sea mines. The advent of ultrawideband sonar transducers together with pulse compression techniques offers a thousandfold increase in the bandwidth-time product of conventional minehunting sonar transmissions enabling stealth mines to be detected at longer ranges. These wideband signals also enable mines to be imaged at safe standoff distances by applying tomographic image reconstruction techniques. The coupling of wideband transducer technology with synthetic aperture processing enhances the resolution of side scan sonars in both the cross-track and along-track directions. The principles on which conventional and advanced minehunting sonars are based are reviewed and the results of applying novel sonar signal processing algorithms to high-frequency sonar data collected in Australian waters are presented.

  3. Cosmogenic activation of a natural tellurium target

    NASA Astrophysics Data System (ADS)

    Lozza, V.; Petzoldt, J.

    2015-02-01

    130Te is one of the candidates for the search for neutrinoless double beta decay. It is currently planned to be used in two experiments: CUORE and SNO+. In the CUORE experiment TeO2 crystals cooled at cryogenic temperatures will be used. In the SNO+ experiment natTe will be deployed up to 0.3% loading in the liquid scintillator volume. A possible background for the signal searched for, are the high Q-value, long-lived isotopes, produced by cosmogenic neutron and proton spallation reaction on the target material. A total of 18 isotopes with Q-value larger than 2 MeV and T1/2 > 20 days have been identified as potential backgrounds. In addition low Q-value, high rate isotopes can be problematic due to pile-up effects, specially in liquid scintillator based detectors. Production rates have been calculated using the ACTIVIA program, the TENDL library, and the cosmogenic neutron and proton flux parametrization at sea level from Armstrong and Gehrels for both long and short lived isotopes. The obtained values for the cross sections are compared with the existing experimental data and calculations. Good agreement has been generally found. The results have been applied to the SNO+ experiment for one year of exposure at sea level. Two possible cases have been considered: a two years of cooling down period deep underground, or a first purification on surface and 6 months of cooling down deep underground. Deep underground activation at the SNOLAB location has been considered.

  4. How targets select activation or repression in response to Wnt.

    PubMed

    Murgan, Sabrina; Bertrand, Vincent

    2015-01-01

    In metazoans, the Wnt signaling pathway plays a key role in the regulation of binary decisions during development. During this process different sets of target genes are activated in cells where the Wnt pathway is active (classic target genes) versus cells where the pathway is inactive (opposite target genes). While the mechanism of transcriptional activation is well understood for classic target genes, how opposite target genes are activated in the absence of Wnt remains poorly characterized. Here we discuss how the key transcriptional mediator of the Wnt pathway, the TCF family member POP-1, regulates opposite target genes during C. elegans development. We examine recent findings suggesting that the direction of the transcriptional output (activation or repression) can be determined by the way TCF is recruited and physically interacts with its target gene. PMID:27123368

  5. Sonar Probing in Narragansett Bay.

    PubMed

    Edgerton, H E; Payson, H; Yules, J; Dillon, W

    1964-12-11

    A 12-kilocycle pulsed transducer, with a 0.1 millisecond duration, is used for tracing a sub-bottom rock profile in Narragansett Bay. The short sonar pulse of high energy is produced by a capacitor discharge. Over-the-side installation of the transducer permits the use of any boat or ship for the survey work. Coherent presentation of the data on a wet paper recorder gives an instantaneous visual record. A cross a north-south rock formation, a recurring rise and fall of the rock is shown throughout the sedimentary deposit.

  6. Computers improves sonar seabed maps

    SciTech Connect

    Not Available

    1984-05-01

    A software package for computer aided mapping of sonar (CAMOS) has been developed in Norway. It has automatic mosaic presentation, which produces fully scale-rectified side scan sonograms automatically plotted on geographical and UTM map grids. The program is the first of its kind in the world. The maps produced by this method are more accurate and detailed than those produced by conventional methods. The main applications of CAMOS are: seafloor mapping; pipeline route surveys; pipeline inspection surveys; platform site surveys; geological mapping and geotechnical investigations. With the aerial-photograph quality of the CAMOS maps, a more accurate and visual representation of the seabed is achieved.

  7. Morphology-Induced Information Transfer in Bat Sonar

    NASA Astrophysics Data System (ADS)

    Reijniers, Jonas; Vanderelst, Dieter; Peremans, Herbert

    2010-10-01

    It has been argued that an important part of understanding bat echolocation comes down to understanding the morphology of the bat sound processing apparatus. In this Letter we present a method based on information theory that allows us to assess target localization performance of bat sonar, without a priori knowledge on the position, size, or shape of the reflecting target. We demonstrate this method using simulated directivity patterns of the frequency-modulated bat Micronycteris microtis. The results of this analysis indicate that the morphology of this bat’s sound processing apparatus has evolved to be a compromise between sensitivity and accuracy with the pinnae and the noseleaf playing different roles.

  8. [Microsurgical removal of deep vascular malformations using sonar-stereometry].

    PubMed

    Reinhardt, H F; Horstmann, G A; Gratzl, O

    1991-04-01

    The advantages of a new, dynamic sonar technology in open stereotactic microsurgery are demonstrated by means of three surgical procedures for deep-seated vascular malformations that are not easy of access. With this method, targets can be aimed at without using rigid, obstructive pointing devices as in conventional stereotaxy. On the contrary, it is possible to take advantage of preformed anatomical spaces reaching the lesion most carefully by means of light-weight, free-hand on-target instruments. The spatial information, correlated with a CT data set, is displayed in real time with an accuracy of +/- 1 mm. Additional image data from MR and digital angiography can be used interactively.

  9. Morphology-induced information transfer in bat sonar.

    PubMed

    Reijniers, Jonas; Vanderelst, Dieter; Peremans, Herbert

    2010-10-01

    It has been argued that an important part of understanding bat echolocation comes down to understanding the morphology of the bat sound processing apparatus. In this Letter we present a method based on information theory that allows us to assess target localization performance of bat sonar, without a priori knowledge on the position, size, or shape of the reflecting target. We demonstrate this method using simulated directivity patterns of the frequency-modulated bat Micronycteris microtis. The results of this analysis indicate that the morphology of this bat's sound processing apparatus has evolved to be a compromise between sensitivity and accuracy with the pinnae and the noseleaf playing different roles.

  10. Sonar Locator Systems

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An underwater locator device called a Pinger is attached to an airplane's flight recorder for recovery in case of a crash. Burnett Electronics Pinger Model 512 resulted from a Burnett Electronics Laboratory, Inc./Langley Research Center contract for development of a search system for underwater mines. The Pinger's battery-powered transmitter is activated when immersed in water, and sends multidirectional signals for up to 500 hours. When a surface receiver picks up the signal, a diver can retrieve the pinger and the attached airplane flight recorder. Other pingers are used to track whales, mark underwater discoveries and assist oil drilling vessels.

  11. Place recognition using batlike sonar

    PubMed Central

    Vanderelst, Dieter; Steckel, Jan; Boen, Andre; Peremans, Herbert; Holderied, Marc W

    2016-01-01

    Echolocating bats have excellent spatial memory and are able to navigate to salient locations using bio-sonar. Navigating and route-following require animals to recognize places. Currently, it is mostly unknown how bats recognize places using echolocation. In this paper, we propose template based place recognition might underlie sonar-based navigation in bats. Under this hypothesis, bats recognize places by remembering their echo signature - rather than their 3D layout. Using a large body of ensonification data collected in three different habitats, we test the viability of this hypothesis assessing two critical properties of the proposed echo signatures: (1) they can be uniquely classified and (2) they vary continuously across space. Based on the results presented, we conclude that the proposed echo signatures satisfy both criteria. We discuss how these two properties of the echo signatures can support navigation and building a cognitive map. DOI: http://dx.doi.org/10.7554/eLife.14188.001 PMID:27481189

  12. 50 CFR 218.100 - Specified activity and specified geographical area.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... active sonar (MFAS) and high frequency active sonar (HFAS) sources, or similar sources, for Navy training...-53 (hull-mounted active sonar)—up to 10865 hours over the course of 5 years (an average of 2173 hours per year); (ii) AN/SQS-56 (hull-mounted active sonar)-up to 705 hours over the course of 5 years...

  13. 50 CFR 216.270 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the following mid-frequency active sonar (MFAS) and high frequency active sonar (HFAS) sources, or...) (estimated amounts below): (i) AN/SQS-53 (hull-mounted active sonar)—up to 9885 hours over the course of 5 years (an average of 1977 hours per year) (ii) AN/SQS-56 (hull-mounted active sonar)—up to 2470...

  14. 50 CFR 218.100 - Specified activity and specified geographical area.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... active sonar (MFAS) and high frequency active sonar (HFAS) sources, or similar sources, for Navy training...-53 (hull-mounted active sonar)—up to 10865 hours over the course of 5 years (an average of 2173 hours per year); (ii) AN/SQS-56 (hull-mounted active sonar)-up to 705 hours over the course of 5 years...

  15. 50 CFR 216.270 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the following mid-frequency active sonar (MFAS) and high frequency active sonar (HFAS) sources, or...) (estimated amounts below): (i) AN/SQS-53 (hull-mounted active sonar)—up to 9885 hours over the course of 5 years (an average of 1977 hours per year) (ii) AN/SQS-56 (hull-mounted active sonar)—up to 2470...

  16. 50 CFR 216.270 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... the following mid-frequency active sonar (MFAS) and high frequency active sonar (HFAS) sources, or...) (estimated amounts below): (i) AN/SQS-53 (hull-mounted active sonar)—up to 9885 hours over the course of 5 years (an average of 1977 hours per year) (ii) AN/SQS-56 (hull-mounted active sonar)—up to 2470...

  17. 50 CFR 218.100 - Specified activity and specified geographical area.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... active sonar (MFAS) and high frequency active sonar (HFAS) sources, or similar sources, for Navy training...-53 (hull-mounted active sonar)—up to 10865 hours over the course of 5 years (an average of 2173 hours per year); (ii) AN/SQS-56 (hull-mounted active sonar)-up to 705 hours over the course of 5 years...

  18. 50 CFR 218.110 - Specified activity and specified geographical area.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources... below: (i) AN/SQS-53 (hull-mounted active sonar)—up to 215 hours over the course of 5 years (an average of 43 hours per year); (ii) AN/SQS-56 (hull-mounted active sonar)—up to 325 hours over the course...

  19. Controlled Sonar Exposure Experiments on Cetaceans in Norwegian Waters: Overview of the 3S-Project.

    PubMed

    Lam, Frans-Peter A; Kvadsheim, Petter H; Miller, Patrick J O; Tyack, Peter L; Ainslie, Michael A; Curé, Charlotte; Kleivane, Lars; Sivle, Lise Doksæter; van Ijsselmuide, Sander P; Visser, Fleur; von Benda-Beckmann, Alexander M; Wensveen, Paul J; Dekeling, René P A

    2016-01-01

    In mitigating the risk of sonar operations, the behavioral response of cetaceans is one of the major knowledge gaps that needs to be addressed. The 3S-Project has conducted a number of controlled exposure experiments with a realistic sonar source in Norwegian waters from 2006 to 2013. In total, the following six target species have been studied: killer, long-finned pilot, sperm, humpback, minke, and northern bottlenose whales. A total of 38 controlled sonar exposures have been conducted on these species. Responses from controlled and repeated exposure runs have been recorded using acoustic and visual observations as well as with electronic tags on the target animal. So far, the first dose-response curves as well as an overview of the scored severity of responses have been revealed. In this paper, an overview is presented of the approach for the study, including the results so far as well as the current status of the ongoing analysis.

  20. Controlled Sonar Exposure Experiments on Cetaceans in Norwegian Waters: Overview of the 3S-Project.

    PubMed

    Lam, Frans-Peter A; Kvadsheim, Petter H; Miller, Patrick J O; Tyack, Peter L; Ainslie, Michael A; Curé, Charlotte; Kleivane, Lars; Sivle, Lise Doksæter; van Ijsselmuide, Sander P; Visser, Fleur; von Benda-Beckmann, Alexander M; Wensveen, Paul J; Dekeling, René P A

    2016-01-01

    In mitigating the risk of sonar operations, the behavioral response of cetaceans is one of the major knowledge gaps that needs to be addressed. The 3S-Project has conducted a number of controlled exposure experiments with a realistic sonar source in Norwegian waters from 2006 to 2013. In total, the following six target species have been studied: killer, long-finned pilot, sperm, humpback, minke, and northern bottlenose whales. A total of 38 controlled sonar exposures have been conducted on these species. Responses from controlled and repeated exposure runs have been recorded using acoustic and visual observations as well as with electronic tags on the target animal. So far, the first dose-response curves as well as an overview of the scored severity of responses have been revealed. In this paper, an overview is presented of the approach for the study, including the results so far as well as the current status of the ongoing analysis. PMID:26611008

  1. Detecting submerged bodies: controlled research using side-scan sonar to detect submerged proxy cadavers.

    PubMed

    Healy, Carrie A; Schultz, John J; Parker, Kenneth; Lowers, Bim

    2015-05-01

    Forensic investigators routinely deploy side-scan sonar for submerged body searches. This study adds to the limited body of literature by undertaking a controlled project to understand how variables affect detection of submerged bodies using side-scan sonar. Research consisted of two phases using small and medium-sized pig (Sus scrofa) carcasses as proxies for human bodies to investigate the effects of terrain, body size, frequency, swath width, and state of decomposition. Results demonstrated that a clear, flat, sandy pond floor terrain was optimal for detection of the target as irregular terrain and/or vegetation are major limitations that can obscure the target. A higher frequency towfish was preferred for small bodies, and a 20 m swath width allowed greater visibility and easier maneuverability of the boat in this environment. Also, the medium-sized carcasses were discernable throughout the 81-day study period, indicating that it is possible to detect bodies undergoing decomposition with side-scan sonar.

  2. Selective attention skills of experienced sonar operators.

    PubMed

    Merrill, L L; Lewandowski, L J; Kobus, D A

    1994-06-01

    This study investigated the influence of sonar training and experience on the selective attention of experienced and inexperienced operators. The Stroop task was selected as a measure of general selective attention, similar in certain task requirements (attentional allocation) to sonar operation. Across two samples (ns = 32 and 36) and four repeated test sessions groups did not differ significantly in speed or accuracy of Stroop performance. The data suggest that experienced operators do not seem to have developed extraordinary attentional skills and that any attentional skills developed through sonar experience do not generalize to other tasks such as the Stroop.

  3. 50 CFR 218.110 - Specified activity and specified geographical area.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... sonar (MFAS) and high frequency active sonar (HFAS) sources, or similar sources, for Navy training...-53 (hull-mounted active sonar)—up to 215 hours over the course of 5 years (an average of 43 hours per year); (ii) AN/SQS-56 (hull-mounted active sonar)—up to 325 hours over the course of 5 years...

  4. 50 CFR 218.110 - Specified activity and specified geographical area.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... sonar (MFAS) and high frequency active sonar (HFAS) sources, or similar sources, for Navy training...-53 (hull-mounted active sonar)—up to 215 hours over the course of 5 years (an average of 43 hours per year); (ii) AN/SQS-56 (hull-mounted active sonar)—up to 325 hours over the course of 5 years...

  5. Evolution: Fossil Ears and Underwater Sonar.

    PubMed

    Lambert, Olivier

    2016-08-22

    A key innovation in the history of whales was the evolution of a sonar system together with high-frequency hearing. Fossils of an archaic toothed whale's inner ear bones provide clues for a stepwise emergence of underwater echolocation ability.

  6. Insights into dolphin sonar discrimination capabilities from human listening experiments.

    PubMed

    Au, W W; Martin, D W

    1989-11-01

    A variety of dolphin sonar discrimination experiments have been conducted, yet little is known about the cues utilized by dolphins in making fine target discriminations. In order to gain insights on cues available to echolocating dolphins, sonar discrimination experiments were conducted with human subjects using the same targets employed in dolphin experiments. When digital recordings of echoes from targets ensonified with a dolphinlike signal were played back at a slower rate to human subjects, they could also make fine target discriminations under controlled laboratory conditions about as well as dolphins under less controlled conditions. Subjects reported that time-separation-pitch and duration cues were important. They also reported that low-amplitude echo components 32 dB below the maximum echo component were usable. The signal-to-noise ratio had to be greater than 10 dB above the detection threshold for simple discrimination and 30 dB for difficult discrimination. Except for two cases in which spectral cues in the form of "click pitch" were important, subjects indicated that time-domain rather than frequency-domain processing seemed to be more relevant in analyzing the echoes.

  7. Analysis of the "Sonar Hopf" cochlea.

    PubMed

    Kern, Albert; Martignoli, Stefan; Mathis, Wolfgang; Steeb, Willi-Hans; Stoop, Ralph Lukas; Stoop, Ruedi

    2011-01-01

    The "Sonar Hopf" cochlea is a recently much advertised engineering design of an auditory sensor. We analyze this approach based on a recent description by its inventors Hamilton, Tapson, Rapson, Jin, and van Schaik, in which they exhibit the "Sonar Hopf" model, its analysis and the corresponding hardware in detail. We identify problems in the theoretical formulation of the model and critically examine the claimed coherence between the described model, the measurements from the implemented hardware, and biological data.

  8. A Fisheries Application of a Dual-Frequency Identification Sonar Acoustic Camera

    SciTech Connect

    Moursund, Russell A.; Carlson, Thomas J.; Peters, Rock D.

    2003-06-01

    The uses of an acoustic camera in fish passage research at hydropower facilities are being explored by the U.S. Army Corps of Engineers. The Dual-Frequency Identification Sonar (DIDSON) is a high-resolution imaging sonar that obtains near video-quality images for the identification of objects underwater. Developed originally for the Navy by the University of Washington?s Applied Physics Laboratory, it bridges the gap between existing fisheries assessment sonar and optical systems. Traditional fisheries assessment sonars detect targets at long ranges but cannot record the shape of targets. The images within 12 m of this acoustic camera are so clear that one can see fish undulating as they swim and can tell the head from the tail in otherwise zero-visibility water. In the 1.8 MHz high-frequency mode, this system is composed of 96 beams over a 29-degree field of view. This high resolution and a fast frame rate allow the acoustic camera to produce near video-quality images of objects through time. This technology redefines many of the traditional limitations of sonar for fisheries and aquatic ecology. Images can be taken of fish in confined spaces, close to structural or surface boundaries, and in the presence of entrained air. The targets themselves can be visualized in real time. The DIDSON can be used where conventional underwater cameras would be limited in sampling range to < 1 m by low light levels and high turbidity, and where traditional sonar would be limited by the confined sample volume. Results of recent testing at The Dalles Dam, on the lower Columbia River in Oregon, USA, are shown.

  9. Nuclease Target Site Selection for Maximizing On-target Activity and Minimizing Off-target Effects in Genome Editing

    PubMed Central

    Lee, Ciaran M; Cradick, Thomas J; Fine, Eli J; Bao, Gang

    2016-01-01

    The rapid advancement in targeted genome editing using engineered nucleases such as ZFNs, TALENs, and CRISPR/Cas9 systems has resulted in a suite of powerful methods that allows researchers to target any genomic locus of interest. A complementary set of design tools has been developed to aid researchers with nuclease design, target site selection, and experimental validation. Here, we review the various tools available for target selection in designing engineered nucleases, and for quantifying nuclease activity and specificity, including web-based search tools and experimental methods. We also elucidate challenges in target selection, especially in predicting off-target effects, and discuss future directions in precision genome editing and its applications. PMID:26750397

  10. Targeted, noninvasive blockade of cortical neuronal activity

    NASA Astrophysics Data System (ADS)

    McDannold, Nathan; Zhang, Yongzhi; Power, Chanikarn; Arvanitis, Costas D.; Vykhodtseva, Natalia; Livingstone, Margaret

    2015-11-01

    Here we describe a novel method to noninvasively modulate targeted brain areas through the temporary disruption of the blood-brain barrier (BBB) via focused ultrasound, enabling focal delivery of a neuroactive substance. Ultrasound was used to locally disrupt the BBB in rat somatosensory cortex, and intravenous administration of GABA then produced a dose-dependent suppression of somatosensory-evoked potentials in response to electrical stimulation of the sciatic nerve. No suppression was observed 1-5 days afterwards or in control animals where the BBB was not disrupted. This method has several advantages over existing techniques: it is noninvasive; it is repeatable via additional GABA injections; multiple brain regions can be affected simultaneously; suppression magnitude can be titrated by GABA dose; and the method can be used with freely behaving subjects. We anticipate that the application of neuroactive substances in this way will be a useful tool for noninvasively mapping brain function, and potentially for surgical planning or novel therapies.

  11. Remote characterizing diffuse hydrothermal flows using multi-beam sonar

    NASA Astrophysics Data System (ADS)

    Ivakin, A. N.; Jackson, D. R.; Bemis, K. G.; Xu, G.

    2015-12-01

    Multi-beam sonars are normally used for bottom bathymetry and backscatter intensity measurements, which provide a base for remotely characterizing the seabed. If not only sonar echo intensity (squared magnitude of acoustic pressure) but also the cross-correlation between successive echoes is measured, then temporal changes in sound speed in the near-bottom environment can be determined. This, in turn, allows estimation of the change of environmental parameters, e.g. temperature variations, as there is a simple linear relationship between sound speed and temperature changes. Stochastic modeling shows that the dependence of the echo decorrelation on the lag time has a relationship with the statistics of temperature variations above the seabed that determine their spatial and temporal scales, power spectra, and structure functions. This approach has been applied to quantify the bottom diffuse hydrothermal flow activity at the Main Endeavour Field on the Juan de Fuca Ridge using the Cabled Observatory Vent Imaging Sonar (COVIS) connected to the Ocean Network Canada's NEPTUNE observatory. In contrast to our previous work, which was focused on spatial imaging of acoustic decorrelation at fixed lag, here the lag dependence of the acoustic structure function is measured and analyzed. This allows extraction of additional parameters of temperature fluctuation statistics. A potential to map diffuse flow using a ROV/HOV is discussed.

  12. Activation of p53 Facilitates the Target Search in DNA by Enhancing the Target Recognition Probability.

    PubMed

    Itoh, Yuji; Murata, Agato; Sakamoto, Seiji; Nanatani, Kei; Wada, Takehiko; Takahashi, Satoshi; Kamagata, Kiyoto

    2016-07-17

    Tumor suppressor p53 binds to the target in a genome and regulates the expression of downstream genes. p53 searches for the target by combining three-dimensional diffusion and one-dimensional sliding along the DNA. To examine the regulation mechanism of the target binding, we constructed the pseudo-wild type (pseudo-WT), activated (S392E), and inactive (R248Q) mutants of p53 and observed their target binding in long DNA using single-molecule fluorescence imaging. The pseudo-WT sliding along the DNA showed many pass events over the target and possessed target recognition probability (TRP) of 7±2%. The TRP increased to 18±2% for the activated mutant but decreased to 0% for the inactive mutant. Furthermore, the fraction of the target binding by the one-dimensional sliding among the total binding events increased from 63±9% for the pseudo-WT to 87±2% for the activated mutant. Control of TRP upon activation, as demonstrated here for p53, might be a general activation mechanism of transcription factors.

  13. An investigation of acoustic beam patterns for the sonar localization problem using a beam based method.

    PubMed

    Guarato, Francesco; Windmill, James; Gachagan, Anthony; Harvey, Gerald

    2013-06-01

    Target localization can be accomplished through an ultrasonic sonar system equipped with an emitter and two receivers. Time of flight of the sonar echoes allows the calculation of the distance of the target. The orientation can be estimated from knowledge of the beam pattern of the receivers and the ratio, in the frequency domain, between the emitted and the received signals after compensation for distance effects and air absorption. The localization method is described and, as its performance strongly depends on the beam pattern, the search of the most appropriate sonar receiver in order to ensure the highest accuracy of target orientation estimations is developed in this paper. The structure designs considered are inspired by the ear shapes of some bat species. Parameters like flare rate, truncation angle, and tragus are considered in the design of the receiver structures. Simulations of the localization method allow us to state which combination of those parameters could provide the best real world implementation. Simulation results show the estimates of target orientations are, in the worst case, 2° with SNR = 50 dB using the receiver structure chosen for a potential practical implementation of a sonar system.

  14. Adaptive filter for mine detection and classification in side-scan sonar imagery

    NASA Astrophysics Data System (ADS)

    Aridgides, Tom; Antoni, Diana; Fernandez, Manuel F.; Dobeck, Gerald J.

    1995-06-01

    A need exists to develop robust automatic techniques for discriminating between minelike target and clutter returns in sonar imagery. To address this need, an adaptive clutter suppression linear FIR filtering technique has been developed and applied to side scan sonar imagery data. The adaptive filtering procedure consists of four stages. First, a normalized average target signature (shape) within the filter window is computed using training set data. Second, the background clutter covariance matrix is computed by scanning the filter window over the data. Third, following substitutions of the average target signature and covariance expressions into a set of normal equations, an adaptive filter is computed which simultaneously suppresses the background clutter while preserving the peak of the average target signature. Finally, the data is filtered using the 2D adaptive range-crossrange filter. The overall mine detection processing string includes automatic gain control, data decimation, adaptive clutter filtering (ACF), 2D normalization, thresholding, exceedance clustering, limiting the number of exceedances and secondary thresholding processing blocks. The utility of the ACF processing string was demonstrated with three side scan sonar datasets. The ACF algorithm provided average probability of detection and false alarm rate performance similar to that obtained when utilizing an expert sonar operator.

  15. An adaptively generated feature set for low-resolution multifrequency sonar images

    NASA Astrophysics Data System (ADS)

    Arrieta, Rodolfo; Arrieta, Lisa L.; Stack, Jason R.

    2006-05-01

    Many small Unmanned Underwater Vehicles (UUVs) currently utilize inexpensive, low resolution sonars that are either mechanically or electronically steered as their main sensors. These sonars do not provide high quality images and are quite dissimilar from the broad area search sonars that will most likely be the source of the localization data given to the UUV in a reacquisition scenario. Therefore, the acoustic data returned by the UUV in its attempt to reacquire the target will look quite different from the original wide area image. The problem then becomes how to determine that the UUV is looking at the same object. Our approach is to exploit the maneuverability of the UUV and currently unused information in the echoes returned from these Commercial-Off-The-Shelf (COTS) sonars in order to classify a presumptive target as an object of interest. The approach hinges on the ability of the UUV to maneuver around the target in order to insonify the target at different frequencies of insonification, ranges, and aspects. We show how this approach would allow the UUV to extract a feature set derived from the inversion of simple physics-based models. These models predict echo time-of-arrival and inversion of these models using the echo data allows effective classification based on estimated surface and bulk material properties. We have simulated UUV maneuvers by positioning targets at different ranges and aspects to the sonar and have then interrogated the target at different frequencies. The properties that have been extracted include longitudinal, and shear speeds of the bulk, as well as longitudinal speed, Rayleigh speed, and density of the surface. The material properties we have extracted using this approach match the tabulated material values within 8%. We also show that only a few material properties are required to effectively segregate many classes of materials.

  16. Active calibration target for bistatic radar cross-section measurements

    NASA Astrophysics Data System (ADS)

    Pienaar, M.; Odendaal, J. W.; Joubert, J.; Cilliers, J. E.; Smit, J. C.

    2016-05-01

    Either passive calibration targets are expensive and complex to manufacture or their bistatic radar cross section (RCS) levels are significantly lower than the monostatic RCS levels of targets such as spheres, dihedral, and trihedral corner reflectors. In this paper the performance of an active calibration target with relative high bistatic RCS values is illustrated as a reference target for bistatic RCS measurements. The reference target is simple to manufacture, operates over a wide frequency range, and can be configured to calibrate all four polarizations (VV, HH, HV, and VH). Bistatic RCS measurements of canonical targets, performed in a controlled environment, are calibrated with the reference target and the results are compared to simulated results using FEKO.

  17. Target Fishing for Chemical Compounds using Target-Ligand Activity data and Ranking based Methods

    PubMed Central

    Wale, Nikil; Karypis, George

    2009-01-01

    In recent years the development of computational techniques that identify all the likely targets for a given chemical compound, also termed as the problem of Target Fishing, has been an active area of research. Identification of likely targets of a chemical compound helps to understand problems such as toxicity, lack of efficacy in humans, and poor physical properties associated with that compound in the early stages of drug discovery. In this paper we present a set of techniques whose goal is to rank or prioritize targets in the context of a given chemical compound such that most targets that this compound may show activity against appear higher in the ranked list. These methods are based on our extensions to the SVM and Ranking Perceptron algorithms for this problem. Our extensive experimental study shows that the methods developed in this work outperform previous approaches by 2% to 60% under different evaluation criterions. PMID:19764745

  18. 50 CFR 216.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-frequency active sonar (MFAS) and high frequency active sonar (HFAS) sources for U.S. Navy anti-submarine warfare (ASW) training in the amounts indicated below (±10 percent): (i) AN/SQS-53 (hull-mounted sonar)—up...-mounted sonar)—up to 1915 hours over the course of 5 years (an average of 383 hours per year) (iii)...

  19. Cancer active targeting by nanoparticles: a comprehensive review of literature

    PubMed Central

    Bazak, Remon; Houri, Mohamad; Achy, Samar El; Kamel, Serag

    2016-01-01

    Purpose Cancer is one of the leading causes of death, and thus, the scientific community has but great efforts to improve cancer management. Among the major challenges in cancer management is development of agents that can be used for early diagnosis and effective therapy. Conventional cancer management frequently lacks accurate tools for detection of early tumors and has an associated risk of serious side effects of chemotherapeutics. The need to optimize therapeutic ratio as the difference with which a treatment affects cancer cells versus healthy tissues lead to idea that it is needful to have a treatment that could act a the “magic bullet”—recognize cancer cells only. Nanoparticle platforms offer a variety of potentially efficient solutions for development of targeted agents that can be exploited for cancer diagnosis and treatment. There are two ways by which targeting of nanoparticles can be achieved, namely passive and active targeting. Passive targeting allows for the efficient localization of nanoparticles within the tumor microenvironment. Active targeting facilitates the active uptake of nanoparticles by the tumor cells themselves. Methods Relevant English electronic databases and scientifically published original articles and reviews were systematically searched for the purpose of this review. Results In this report, we present a comprehensive review of literatures focusing on the active targeting of nanoparticles to cancer cells, including antibody and antibody fragment-based targeting, antigen-based targeting, aptamer-based targeting, as well as ligand-based targeting. Conclusion To date, the optimum targeting strategy has not yet been announced, each has its own advantages and disadvantages even though a number of them have found their way for clinical application. Perhaps, a combination of strategies can be employed to improve the precision of drug delivery, paving the way for a more effective personalized therapy. PMID:25005786

  20. Swath sonar mapping of Earth's submarine plate boundaries

    NASA Astrophysics Data System (ADS)

    Carbotte, S. M.; Ferrini, V. L.; Celnick, M.; Nitsche, F. O.; Ryan, W. B. F.

    2014-12-01

    The recent loss of Malaysia Airlines flight MH370 in an area of the Indian Ocean where less than 5% of the seafloor is mapped with depth sounding data (Smith and Marks, EOS 2014) highlights the striking lack of detailed knowledge of the topography of the seabed for much of the worlds' oceans. Advances in swath sonar mapping technology over the past 30 years have led to dramatic improvements in our capability to map the seabed. However, the oceans are vast and only an estimated 10% of the seafloor has been mapped with these systems. Furthermore, the available coverage is highly heterogeneous and focused within areas of national strategic priority and community scientific interest. The major plate boundaries that encircle the globe, most of which are located in the submarine environment, have been a significant focus of marine geoscience research since the advent of swath sonar mapping. While the location of these plate boundaries are well defined from satellite-derived bathymetry, significant regions remain unmapped at the high-resolutions provided by swath sonars and that are needed to study active volcanic and tectonic plate boundary processes. Within the plate interiors, some fossil plate boundary zones, major hotspot volcanoes, and other volcanic provinces have been the focus of dedicated research programs. Away from these major tectonic structures, swath mapping coverage is limited to sparse ocean transit lines which often reveal previously unknown deep-sea channels and other little studied sedimentary structures not resolvable in existing low-resolution global compilations, highlighting the value of these data even in the tectonically quiet plate interiors. Here, we give an overview of multibeam swath sonar mapping of the major plate boundaries of the globe as extracted from public archives. Significant quantities of swath sonar data acquired from deep-sea regions are in restricted-access international archives. Open access to more of these data sets would

  1. Target structure and echo spectral discrimination by echolocating bats.

    PubMed

    Simmons, J A; Lavender, W A; Lavender, B A; Doroshow, C A; Kiefer, S W; Livingston, R; Scallet, A C; Crowley, D E

    1974-12-20

    Echolocating bats can use sonar to discriminate among targets which reflect echoes differing in spectral distribution of energy but not in overall intensity. They can detect differences smaller than 1 millimeter in fine target structure. Bats may be capable of classifying targets from echo spectral signatures and might thus be able to distinguish among flying insect prey by sonar.

  2. Targeted Deficiency of the Transcriptional Activator Hnf1α Alters Subnuclear Positioning of Its Genomic Targets

    PubMed Central

    Sadoni, Nicolas; Zink, Daniele; Ferrer, Jorge

    2008-01-01

    DNA binding transcriptional activators play a central role in gene-selective regulation. In part, this is mediated by targeting local covalent modifications of histone tails. Transcriptional regulation has also been associated with the positioning of genes within the nucleus. We have now examined the role of a transcriptional activator in regulating the positioning of target genes. This was carried out with primary β-cells and hepatocytes freshly isolated from mice lacking Hnf1α, an activator encoded by the most frequently mutated gene in human monogenic diabetes (MODY3). We show that in Hnf1a−/− cells inactive endogenous Hnf1α-target genes exhibit increased trimethylated histone H3-Lys27 and reduced methylated H3-Lys4. Inactive Hnf1α-targets in Hnf1a−/− cells are also preferentially located in peripheral subnuclear domains enriched in trimethylated H3-Lys27, whereas active targets in wild-type cells are positioned in more central domains enriched in methylated H3-Lys4 and RNA polymerase II. We demonstrate that this differential positioning involves the decondensation of target chromatin, and show that it is spatially restricted rather than a reflection of non-specific changes in the nuclear organization of Hnf1a-deficient cells. This study, therefore, provides genetic evidence that a single transcriptional activator can influence the subnuclear location of its endogenous genomic targets in primary cells, and links activator-dependent changes in local chromatin structure to the spatial organization of the genome. We have also revealed a defect in subnuclear gene positioning in a model of a human transcription factor disease. PMID:18497863

  3. Shallow water imaging sonar system for environmental surveying. Final report

    SciTech Connect

    1998-05-01

    The scope of this research is to develop a shallow water sonar system designed to detect and map the location of objects such as hazardous wastes or discarded ordnance in coastal waters. The system will use high frequency wide-bandwidth imaging sonar, mounted on a moving platform towed behind a boat, to detect and identify objects on the sea bottom. Resolved images can be obtained even if the targets are buried in an overlayer of silt. The specific technical objective of this research was to develop and test a prototype system that is capable of (1) scan at high speeds (up to 10m/s), even in shallow water (depth to ten meters), without motion blurring or loss of resolution; (2) produce images of the bottom structure that are detailed enough for unambiguous detection of objects as small as 15cm, even if they are buried up to 30cm deep in silt or sand. The critical technology involved uses an linear FM (LFM) or similar complex waveform, which has a high bandwidth for good range resolution, with a long pulse length for similar Dopper resolution. The lone duration signal deposits more energy on target than a narrower pulse, which increases the signal-to-noise ratio and signal-to-clutter ratio. This in turn allows the use of cheap, lightweight, low power, piezoelectric transducers at the 30--500 kHz range.

  4. More than the Bottom: Multibeam Sonars and Water-column Imaging (Invited)

    NASA Astrophysics Data System (ADS)

    Mayer, L. A.; Weber, T.; Gardner, J. V.; Malik, M.; Doucet, M.; Beaudoin, J.

    2010-12-01

    The past ten years have seen remarkable advances in our ability to rapidly and accurately map the seafloor. Improvements in sonar design and signal processing have dramatically increased both the spatial and temporal resolution of seafloor mapping systems as well as provided the opportunity to extract information about seafloor character through the concomitant mapping of seafloor backscatter. The latest generation of multibeam sonars, however, can now provide acoustic returns from the water-column as well as from the seafloor. When combined with powerful new visualization tools, the ability to acoustically map large volumes of the water-column opens up vast new areas of application for multibeam sonar data. When applied to the most traditional use of multibeam sonar data (seafloor mapping in support of safe navigation), water-column data afford the opportunity to see small, high-standing targets (like ship’s masts) and offer a powerful tool for critically needed, least-depth detection. Water-column data collected from multibeam sonars also provide numerous opportunities for fisheries research ranging from qualitative descriptions of fish school behavior and vessel avoidance studies (the systems can make measurements well beyond the limited, normal-incidence view of traditional fisheries sonars), to the eventual quantitative measurements of volume backscatter (as systems become more calibrated). Increases in system bandwidth will also open opportunities for target identification studies. With increased bandwith will also come the potential for tuning the systems for the mapping of watermass boundaries, offering a powerful tool for a range of physical oceanographic applications. Finally, the ability to map the water-column has great potential for quantifying the flux of methane into the ocean from natural (and un-natural) seeps. Water-column mapping has already proven a valuable asset in monitoring the Deepwater Horizon well-site for potential blow-outs or gas

  5. Enhanced Active Targeting via Cooperative Binding of Ligands on Liposomes to Target Receptors

    PubMed Central

    Sugiyama, Tomoki; Asai, Tomohiro; Nedachi, Yuki Murase; Katanasaka, Yasufumi; Shimizu, Kosuke; Maeda, Noriyuki; Oku, Naoto

    2013-01-01

    To achieve effective active targeting in a drug delivery system, we previously developed dual-targeting (DT) liposomes decorated with both vascular endothelial growth factor receptor-1 (VEGFR-1)-targeted APRPG and CD13-targeted GNGRG peptide ligands for tumor neovessels, and observed the enhanced suppression of tumor growth in Colon26 NL-17 tumor-bearing mice by the treatment with the DT liposomes encapsulating doxorubicin. In this present study, we examined the binding characteristics of DT liposomes having a different couple of ligands, namely, APRPG and integrin αvβ3-targeted GRGDS peptides. These DT liposomes synergistically associated to stimulated human umbilical vein endothelial cells compared with single-targeting (ST) liposomes decorated with APRPG or GRGDS. The results of a surface plasmon resonance assay showed that ST liposomes modified with APRPG or GRGDS peptide selectively bound to immobilized VEGFR-1 or integrin αvβ3, respectively. DT liposomes showed a higher affinity for a mixture of VEGFR-1 and integrin αvβ3 compared with ST liposomes, suggesting the cooperative binding of these 2 kinds of ligand on the liposomal surface. In a biodistribution assay, the DT liposomes accumulated to a significantly greater extent in the tumors of Colon26 NL-17 tumor-bearing mice compared with other liposomes. Moreover, the intratumoral distribution of the liposomes examined by confocal microscopy suggested that the DT liposomes targeted not only angiogenic endothelial cells but also tumor cells due to GRGDS-decoration. These findings suggest that "dual-targeting" augmented the affinity of the liposomes for the target cells and would thus be useful for active-targeting drug delivery for cancer treatment. PMID:23840738

  6. High efficiency cell-specific targeting of cytokine activity

    NASA Astrophysics Data System (ADS)

    Garcin, Geneviève; Paul, Franciane; Staufenbiel, Markus; Bordat, Yann; van der Heyden, José; Wilmes, Stephan; Cartron, Guillaume; Apparailly, Florence; de Koker, Stefaan; Piehler, Jacob; Tavernier, Jan; Uzé, Gilles

    2014-01-01

    Systemic toxicity currently prevents exploiting the huge potential of many cytokines for medical applications. Here we present a novel strategy to engineer immunocytokines with very high targeting efficacies. The method lies in the use of mutants of toxic cytokines that markedly reduce their receptor-binding affinities, and that are thus rendered essentially inactive. Upon fusion to nanobodies specifically binding to marker proteins, activity of these cytokines is selectively restored for cell populations expressing this marker. This ‘activity-by-targeting’ concept was validated for type I interferons and leptin. In the case of interferon, activity can be directed to target cells in vitro and to selected cell populations in mice, with up to 1,000-fold increased specific activity. This targeting strategy holds promise to revitalize the clinical potential of many cytokines.

  7. The sonar beam pattern of a flying bat as it tracks tethered insects.

    PubMed

    Ghose, Kaushik; Moss, Cynthia F

    2003-08-01

    This paper describes measurements of the sonar beam pattern of flying echolocating bats, Eptesicus fuscus, performing various insect capture tasks in a large laboratory flight room. The beam pattern is deduced using the signal intensity across a linear array of microphones. The positions of the bat and insect prey are obtained by stereoscopic reconstruction from two camera views. Results are reported in the form of beam-pattern plots and estimated direction of the beam axis. The bat centers its beam axis on the selected target with a standard deviation (sigma) of 3 degrees. The experimental error is +/- 1.4 degrees. Trials conducted with two targets show that the bat consistently tracks one of the targets with its beam. These findings suggest that the axis of the bat sonar beam is a good index of selective tracking of targets, and in this respect is analogous to gaze in predominantly visual animals.

  8. Multibeam sonar (DIDSON) assessment of American shad (Alosa sapidissima) approaching a hydroelectric dam

    USGS Publications Warehouse

    Grote, Ann B.; Bailey, Michael M.; Zydlewski, Joseph; Hightower, Joseph E.

    2014-01-01

    We investigated the fish community approaching the Veazie Dam on the Penobscot River, Maine, prior to implementation of a major dam removal and river restoration project. Multibeam sonar (dual-frequency identification sonar, DIDSON) surveys were conducted continuously at the fishway entrance from May to July in 2011. A 5% subsample of DIDSON data contained 43 793 fish targets, the majority of which were of Excellent (15.7%) or Good (73.01%) observation quality. Excellent quality DIDSON targets (n = 6876) were apportioned by species using a Bayesian mixture model based on four known fork length distributions (river herring (alewife,Alosa psuedoharengus, and blueback herring, Alosa aestivalis), American shad, Alosa sapidissima) and two size classes (one sea-winter and multi-sea-winter) of Atlantic salmon (Salmo salar). 76.2% of targets were assigned to the American shad distribution; Atlantic salmon accounted for 15.64%, and river herring 8.16% of observed targets. Shad-sized (99.0%) and salmon-sized (99.3%) targets approached the fishway almost exclusively during the day, whereas river herring-sized targets were observed both during the day (51.1%) and at night (48.9%). This approach demonstrates how multibeam sonar imaging can be used to evaluate community composition and species-specific movement patterns in systems where there is little overlap in the length distributions of target species.

  9. The use of multidimensional perceptual models in the selection of sonar echo features.

    PubMed

    Gorman, R P; Sawatari, T

    1985-03-01

    The development of an accurate and efficient sonar-target classification system depends upon the identification of a set of signal features which may be used to discriminate important classes of signals. Feature selection can be facilitated through the identification of perceptual features used by human listeners in discriminating relevant sonar echoes. This study was conducted to establish a more reliable means of identifying perceptual features in terms of physical signal parameters as an initial step toward the development of an automatic sonar-target classification system. The results of an experiment involving eight subjects and six sonar echoes are presented. A model of the perceptual structure of these echoes was derived from subject similarity judgments using a multidimensional scaling (MDS) technique. It was found that three perceptual features accounted for the similarity judgments made by the human listeners. Echoes modified along candidate physical dimensions were employed to aid in the identification of perceptual dimensions in terms of physical signal parameters. The three perceptual features could be associated with signal parameters involving the amplitude envelope of the echoes.

  10. An auditory event related potential evaluation of sonar task experience and age.

    PubMed

    Merrill, L L; Kobus, D A; McGuigan, F J

    1995-06-01

    To gauge the interaction of real-world sonar-task experience and age on brain electrical activity, the effect of sonar experience and age on event related potentials (ERP) was examined. A three-group design was used and the results suggest that sonar experience and age affect the amplitude and distribution of the ERP component. The results concerning age and ERPs support and extend the results of previous studies and suggest that age-related differences occur at a much younger age than is reported elsewhere. Attentional and stimulus evaluation processes which have been linked to parameters of the ERP component may be enhanced with real-world auditory task experience. Research on ERP should control for the possible confounds of auditory-task experience and age.

  11. Mitochondrial Nitroreductase Activity Enables Selective Imaging and Therapeutic Targeting.

    PubMed

    Chevalier, Arnaud; Zhang, Yanmin; Khdour, Omar M; Kaye, Justin B; Hecht, Sidney M

    2016-09-21

    Nitroreductase (NTR) activities have been known for decades, studied extensively in bacteria and also in systems as diverse as yeast, trypanosomes, and hypoxic tumors. The putative bacterial origin of mitochondria prompted us to explore the possible existence of NTR activity within this organelle and to probe its behavior in a cellular context. Presently, by using a profluorescent near-infrared (NIR) dye, we characterize the nature of NTR activity localized in mammalian cell mitochondria. Further, we demonstrate that this mitochondrially localized enzymatic activity can be exploited both for selective NIR imaging of mitochondria and for mitochondrial targeting by activating a mitochondrial poison specifically within that organelle. This constitutes a new mechanism for mitochondrial imaging and targeting. These findings represent the first use of mitochondrial enzyme activity to unmask agents for mitochondrial fluorescent imaging and therapy, which may prove to be more broadly applicable.

  12. Sonar investigations in the Laghi di Monticchio (Mt. Vúlture, Italy)

    NASA Astrophysics Data System (ADS)

    Hansen, Ralph B.

    Sonar profiles across the Lago Grande and Lago Piccolo di Monticchio (two lakes in southern Italy, 20 km S of Melfi) were recorded to get knowledge on the lake basins an their surface prior coring. The combination of echo-graph data with digital landscape modelling was suitable for the detection and interpretation of complex structures of the lake bottom. The interpretation of the model shows the distortion of an old continuous sedimentation by younger tectonic events. The presence of terraces above and below the present-day lake level are interpreted as response to paleoclimatic fluctuations and human activities.

  13. Changes in dive behavior during naval sonar exposure in killer whales, long-finned pilot whales, and sperm whales

    PubMed Central

    Sivle, L. D.; Kvadsheim, P. H.; Fahlman, A.; Lam, F. P. A.; Tyack, P. L.; Miller, P. J. O.

    2012-01-01

    Anthropogenic underwater sound in the environment might potentially affect the behavior of marine mammals enough to have an impact on their reproduction and survival. Diving behavior of four killer whales (Orcinus orca), seven long-finned pilot whales (Globicephala melas), and four sperm whales (Physeter macrocephalus) was studied during controlled exposures to naval sonar [low frequency active sonar (LFAS): 1–2 kHz and mid frequency active sonar (MFAS): 6–7 kHz] during three field seasons (2006–2009). Diving behavior was monitored before, during and after sonar exposure using an archival tag placed on the animal with suction cups. The tag recorded the animal's vertical movement, and additional data on horizontal movement and vocalizations were used to determine behavioral modes. Killer whales that were conducting deep dives at sonar onset changed abruptly to shallow diving (ShD) during LFAS, while killer whales conducting deep dives at the onset of MFAS did not alter dive mode. When in ShD mode at sonar onset, killer whales did not change their diving behavior. Pilot and sperm whales performed normal deep dives (NDD) during MFAS exposure. During LFAS exposures, long-finned pilot whales mostly performed fewer deep dives and some sperm whales performed shallower and shorter dives. Acoustic recording data presented previously indicates that deep diving (DD) is associated with feeding. Therefore, the observed changes in dive behavior of the three species could potentially reduce the foraging efficiency of the affected animals. PMID:23087648

  14. Changes in dive behavior during naval sonar exposure in killer whales, long-finned pilot whales, and sperm whales.

    PubMed

    Sivle, L D; Kvadsheim, P H; Fahlman, A; Lam, F P A; Tyack, P L; Miller, P J O

    2012-01-01

    Anthropogenic underwater sound in the environment might potentially affect the behavior of marine mammals enough to have an impact on their reproduction and survival. Diving behavior of four killer whales (Orcinus orca), seven long-finned pilot whales (Globicephala melas), and four sperm whales (Physeter macrocephalus) was studied during controlled exposures to naval sonar [low frequency active sonar (LFAS): 1-2 kHz and mid frequency active sonar (MFAS): 6-7 kHz] during three field seasons (2006-2009). Diving behavior was monitored before, during and after sonar exposure using an archival tag placed on the animal with suction cups. The tag recorded the animal's vertical movement, and additional data on horizontal movement and vocalizations were used to determine behavioral modes. Killer whales that were conducting deep dives at sonar onset changed abruptly to shallow diving (ShD) during LFAS, while killer whales conducting deep dives at the onset of MFAS did not alter dive mode. When in ShD mode at sonar onset, killer whales did not change their diving behavior. Pilot and sperm whales performed normal deep dives (NDD) during MFAS exposure. During LFAS exposures, long-finned pilot whales mostly performed fewer deep dives and some sperm whales performed shallower and shorter dives. Acoustic recording data presented previously indicates that deep diving (DD) is associated with feeding. Therefore, the observed changes in dive behavior of the three species could potentially reduce the foraging efficiency of the affected animals.

  15. Targeted Gene Activation Using RNA-Guided Nucleases.

    PubMed

    Brown, Alexander; Woods, Wendy S; Perez-Pinera, Pablo

    2017-01-01

    The discovery of the prokaryotic CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated) system and its adaptation for targeted manipulation of DNA in diverse species has revolutionized the field of genome engineering. In particular, the fusion of catalytically inactive Cas9 to any number of transcriptional activator domains has resulted in an array of easily customizable synthetic transcription factors that are capable of achieving robust, specific, and tunable activation of target gene expression within a wide variety of tissues and cells. This chapter describes key experimental design considerations, methods for plasmid construction, gene delivery protocols, and procedures for analysis of targeted gene activation in mammalian cell lines using CRISPR-Cas transcription factors. PMID:27662880

  16. Representation of multi-target activity landscapes through target pair-based compound encoding in self-organizing maps.

    PubMed

    Iyer, Preeti; Bajorath, Jürgen

    2011-11-01

    Activity landscape representations provide access to structure-activity relationships information in compound data sets. In general, activity landscape models integrate molecular similarity relationships with biological activity data. Typically, activity against a single target is monitored. However, for steadily increasing numbers of compounds, activity against multiple targets is reported, resulting in an opportunity, and often a need, to explore multi-target structure-activity relationships. It would be attractive to utilize activity landscape representations to aid in this process, but the design of activity landscapes for multiple targets is a complicated task. Only recently has a first multi-target landscape model been introduced, consisting of an annotated compound network focused on the systematic detection of activity cliffs. Herein, we report a conceptually different multi-target activity landscape design that is based on a 2D projection of chemical reference space using self-organizing maps and encodes compounds as arrays of pair-wise target activity relationships. In this context, we introduce the concept of discontinuity in multi-target activity space. The well-ordered activity landscape model highlights centers of discontinuity in activity space and is straightforward to interpret. It has been applied to analyze compound data sets with three, four, and five target annotations and identify multi-target structure-activity relationships determinants in analog series.

  17. Processing of AUV Sidescan Sonar Images for Enhancement and Classification

    NASA Astrophysics Data System (ADS)

    Honsho, C.; Asada, A.; Ura, T.; Kim, K.

    2014-12-01

    An arc volcano hosting a hydrothermal field was surveyed by using an autonomous underwater vehicle equipped with a sidescan sonar system and a multibeam echo sounder. The survey area is relatively small in area but has large variations in bathymetry and geology. To correct large geometric distortions in sidescan images, actual topographic cross sections cut by fan beams were taken into consideration instead of assuming flat bottoms. Beam pattern corrections were cautiously performed in combination with theoretical radiometric corrections for slant range and incident angle. These detailed geometric and radiometric corrections were efficient to patch neighboring images and build a complete picture of the whole survey area. Three textural attributes were computed from the corrected images by means of grey level co-occurrence matrices and used for the seafloor classification. As no ground truth data were available to us, we used a cluster analysis for the classification and obtained a result that seems relevant to the geological features suggested by the topography. Moreover, slopes of the caldera wall and of the central cones are clearly differentiated in the classification result, though the difference is not immediately obvious to our eyes. As one of the classes clearly delineates a known hydrothermal field, we expect by analogy that this class will highlight hydrothermal features in the survey area, helping to detect potential targets to be specifically investigated for mineral exploration. Numerical processing of sonar images effectively complements their visual inspection with human eyes and is helpful in providing a different perspective.

  18. A Systolic Array Architecture For Processing Sonar Narrowband Signals

    NASA Astrophysics Data System (ADS)

    Mintzer, L.

    1988-07-01

    Modern sonars relay more upon visual rather than aural contacts. Lofargrams presenting a time history of hydrophone spectral content are standard means of observing narrowband signals. However, the frequency signal "tracks" are often embedded in noise, sometimes rendering their detection difficult and time consuming. Image enhancement algorithms applied to the 'grams can yield improvements in target data presented to the observer. A systolic array based on the NCR Geometric Arithmetic Parallel Processor (GAPP), a CMOS chip that contains 72 single bit processors controlled in parallel, has been designed for evaluating image enhancement algorithms. With the processing nodes of the GAPP bearing a one-to-one correspondence with the pixels displayed on the 'gram, a very efficient SIMD architecture is realized. The low data rate of sonar displays, i.e., one line of 1000-4000 pixels per second, and the 10-MHz control clock of the GAPP provide the possibility of 107 operations per pixel in real time applications. However, this architecture cannot handle data-dependent operations efficiently. To this end a companion processor capable of efficiently executing branch operations has been designed. A simple spoke filter is simulated and applied to laboratory data with noticeable improvements in the resulting lofargram display.

  19. High thresholds for avoidance of sonar by free-ranging long-finned pilot whales (Globicephala melas).

    PubMed

    Antunes, R; Kvadsheim, P H; Lam, F P A; Tyack, P L; Thomas, L; Wensveen, P J; Miller, P J O

    2014-06-15

    The potential effects of exposing marine mammals to military sonar is a current concern. Dose-response relationships are useful for predicting potential environmental impacts of specific operations. To reveal behavioral response thresholds of exposure to sonar, we conducted 18 exposure/control approaches to 6 long-finned pilot whales. Source level and proximity of sonar transmitting one of two frequency bands (1-2 kHz and 6-7 kHz) were increased during exposure sessions. The 2-dimensional movement tracks were analyzed using a changepoint method to identify the avoidance response thresholds which were used to estimate dose-response relationships. No support for an effect of sonar frequency or previous exposures on the probability of response was found. Estimated response thresholds at which 50% of population show avoidance (SPLmax=170 dB re 1 μPa, SELcum=173 dB re 1 μPa(2) s) were higher than previously found for other cetaceans. The US Navy currently uses a generic dose-response relationship to predict the responses of cetaceans to naval active sonar, which has been found to underestimate behavioural impacts on killer whales and beaked whales. The navy curve appears to match more closely our results with long-finned pilot whales, though it might underestimate the probability of avoidance for pilot-whales at long distances from sonar sources. PMID:24820645

  20. High thresholds for avoidance of sonar by free-ranging long-finned pilot whales (Globicephala melas).

    PubMed

    Antunes, R; Kvadsheim, P H; Lam, F P A; Tyack, P L; Thomas, L; Wensveen, P J; Miller, P J O

    2014-06-15

    The potential effects of exposing marine mammals to military sonar is a current concern. Dose-response relationships are useful for predicting potential environmental impacts of specific operations. To reveal behavioral response thresholds of exposure to sonar, we conducted 18 exposure/control approaches to 6 long-finned pilot whales. Source level and proximity of sonar transmitting one of two frequency bands (1-2 kHz and 6-7 kHz) were increased during exposure sessions. The 2-dimensional movement tracks were analyzed using a changepoint method to identify the avoidance response thresholds which were used to estimate dose-response relationships. No support for an effect of sonar frequency or previous exposures on the probability of response was found. Estimated response thresholds at which 50% of population show avoidance (SPLmax=170 dB re 1 μPa, SELcum=173 dB re 1 μPa(2) s) were higher than previously found for other cetaceans. The US Navy currently uses a generic dose-response relationship to predict the responses of cetaceans to naval active sonar, which has been found to underestimate behavioural impacts on killer whales and beaked whales. The navy curve appears to match more closely our results with long-finned pilot whales, though it might underestimate the probability of avoidance for pilot-whales at long distances from sonar sources.

  1. Automatic seagrass pattern identification on sonar images

    NASA Astrophysics Data System (ADS)

    Rahnemoonfar, Maryam; Rahman, Abdullah

    2016-05-01

    Natural and human-induced disturbances are resulting in degradation and loss of seagrass. Freshwater flooding, severe meteorological events and invasive species are among the major natural disturbances. Human-induced disturbances are mainly due to boat propeller scars in the shallow seagrass meadows and anchor scars in the deeper areas. Therefore, there is a vital need to map seagrass ecosystems in order to determine worldwide abundance and distribution. Currently there is no established method for mapping the pothole or scars in seagrass. One of the most precise sensors to map the seagrass disturbance is side scan sonar. Here we propose an automatic method which detects seagrass potholes in sonar images. Side scan sonar images are notorious for having speckle noise and uneven illumination across the image. Moreover, disturbance presents complex patterns where most segmentation techniques will fail. In this paper, by applying mathematical morphology technique and calculating the local standard deviation of the image, the images were enhanced and the pothole patterns were identified. The proposed method was applied on sonar images taken from Laguna Madre in Texas. Experimental results show the effectiveness of the proposed method.

  2. Evolution: Fossil Ears and Underwater Sonar.

    PubMed

    Lambert, Olivier

    2016-08-22

    A key innovation in the history of whales was the evolution of a sonar system together with high-frequency hearing. Fossils of an archaic toothed whale's inner ear bones provide clues for a stepwise emergence of underwater echolocation ability. PMID:27554653

  3. Short delays and low pulse amplitudes produce widespread activation in the target-distance processing area of auditory cortex of the mustached bat.

    PubMed

    Macías, Silvio; Hechavarría, Julio C

    2016-08-01

    While approaching an object, echolocating bats decrease the amplitude of their vocalizations. This behavior is known as "echo-level compensation." Here, the activation pattern of the cortical FM-FM (frequency modulated) area of the mustached bat is assessed by using acoustic stimuli that correspond to sonar signals and their echoes emitted during echo-level compensation behavior. Activation maps were calculated from the delay response areas of 86 cortical neurons, and these maps were used to explore the topography of cortical activation during echolocation and its relation to the bats' cortical "chronotopy." Chronotopy predicts short echo-delays to be represented by rostral auditory cortex neurons while caudal neurons represent long echo-delays. The results show that a chronotopic activation of the cortex is evident only at loud pulse amplitudes [80-90 dB sound pressure level (SPL)]. In response to fainter pulse levels (60-70 dB SPL), as those produced as the animals zoom-in on targets, chronotopic activation of the cortex becomes less clear because units throughout the FM-FM area start firing, especially in response to short echo-delays. The fact that cortical activity is more widespread in response to combinations of short echo-delays and faint pulse amplitudes could represent an adaptation that enhances cortical activity in the late stages of echo-level compensation. PMID:27586724

  4. Short delays and low pulse amplitudes produce widespread activation in the target-distance processing area of auditory cortex of the mustached bat.

    PubMed

    Macías, Silvio; Hechavarría, Julio C

    2016-08-01

    While approaching an object, echolocating bats decrease the amplitude of their vocalizations. This behavior is known as "echo-level compensation." Here, the activation pattern of the cortical FM-FM (frequency modulated) area of the mustached bat is assessed by using acoustic stimuli that correspond to sonar signals and their echoes emitted during echo-level compensation behavior. Activation maps were calculated from the delay response areas of 86 cortical neurons, and these maps were used to explore the topography of cortical activation during echolocation and its relation to the bats' cortical "chronotopy." Chronotopy predicts short echo-delays to be represented by rostral auditory cortex neurons while caudal neurons represent long echo-delays. The results show that a chronotopic activation of the cortex is evident only at loud pulse amplitudes [80-90 dB sound pressure level (SPL)]. In response to fainter pulse levels (60-70 dB SPL), as those produced as the animals zoom-in on targets, chronotopic activation of the cortex becomes less clear because units throughout the FM-FM area start firing, especially in response to short echo-delays. The fact that cortical activity is more widespread in response to combinations of short echo-delays and faint pulse amplitudes could represent an adaptation that enhances cortical activity in the late stages of echo-level compensation.

  5. Active Targeted Drug Delivery for Microbes Using Nano-Carriers

    PubMed Central

    Lin, Yung-Sheng; Lee, Ming-Yuan; Yang, Chih-Hui; Huang, Keng-Shiang

    2015-01-01

    Although vaccines and antibiotics could kill or inhibit microbes, many infectious diseases remain difficult to treat because of acquired resistance and adverse side effects. Nano-carriers-based technology has made significant progress for a long time and is introducing a new paradigm in drug delivery. However, it still has some challenges like lack of specificity toward targeting the infectious site. Nano-carriers utilized targeting ligands on their surface called ‘active target’ provide the promising way to solve the problems like accelerating drug delivery to infectious areas and preventing toxicity or side-effects. In this mini review, we demonstrate the recent studies using the active targeted strategy to kill or inhibit microbes. The four common nano-carriers (e.g. liposomes, nanoparticles, dendrimers and carbon nanotubes) delivering encapsulated drugs are introduced. PMID:25877093

  6. Assessing a dual-frequency identification sonars' fish-counting accuracy, precision, and turbid river range capability.

    PubMed

    Maxwell, Suzanne L; Gove, Nancy E

    2007-12-01

    Accurately assessing migrating salmon populations in turbid rivers with hydroacoustics is challenging. Using single, dual, or split-beam sonars, difficulties occur fitting acoustic beams between the river's narrow boundaries, distinguishing fish from nonfish echoes, and resolving individual fish at high densities. To address these issues, the fish-counting capability of a dual-frequency identification sonar (DIDSON), which produces high resolution, video-like images, was assessed. In a clear river, fish counts generated from a DIDSON, an echo counter, split-beam sonar, and video were compared to visual counts from a tower, a method frequently used to ground-truth sonars. The DIDSON and tower counts were very similar and showed the strongest agreement and least variability compared to the other methods. In a highly turbid river, the DIDSON's maximum detection range for a 10.16 cm spherical target was 17 m, less than absorption and wave spreading losses predict, and 26 m in clear water. Unlike tower and video methods, the DIDSON was not limited by surface disturbances or turbidity. DIDSON advantages over other sonars include: better target resolution; wider viewing angle; better coverage of the water column; accurate direction of travel; and simpler to aim and operate.

  7. Effect of target probability on pre-stimulus brain activity.

    PubMed

    Lucci, G; Berchicci, M; Perri, R L; Spinelli, D; Di Russo, F

    2016-05-13

    Studies on perceptual decision-making showed that manipulating the proportion of target and non-target stimuli affects the behavioral performance. Tasks with high frequency of targets are associated to faster response times (RTs) conjunctively to higher number of errors (reflecting a response bias characterized by speed/accuracy trade-off) when compared to conditions with low frequency of targets. Electroencephalographic studies well described modulations of post-stimulus event-related potentials as effect of the stimulus probability; in contrast, in the present study we focused on the pre-stimulus preparatory activities subtending the response bias. Two versions of a Go/No-go task characterized by different proportion of Go stimuli (88% vs. 12%) were adopted. In the task with frequent go trials, we observed a strong enhancement in the motor preparation as indexed by the Bereitschaftspotential (BP, previously associated with activity within the supplementary motor area), faster RTs, and larger commission error rate than in the task with rare go trials. Contemporarily with the BP, a right lateralized prefrontal negativity (lateral pN, previously associated with activity within the dorsolateral prefrontal cortex) was larger in the task with rare go trial. In the post-stimulus processing stage, we confirmed that the N2 and the P3 components were larger for rare trials, irrespective of the Go/No-go stimulus category. The increase of activities recorded in the preparatory phase related to frequency of targets is consistent with the view proposed in accumulation models of perceptual decision for which target frequency affects the subjective baseline, reducing the distance between the starting-point and the response boundary, which determines the response speed. PMID:26912279

  8. Study of Natural Health Product Adverse Reactions (SONAR): Active Surveillance of Adverse Events Following Concurrent Natural Health Product and Prescription Drug Use in Community Pharmacies

    PubMed Central

    Vohra, Sunita; Cvijovic, Kosta; Boon, Heather; Foster, Brian C.; Jaeger, Walter; LeGatt, Don; Cembrowski, George; Murty, Mano; Tsuyuki, Ross T.; Barnes, Joanne; Charrois, Theresa L.; Arnason, John T.; Necyk, Candace; Ware, Mark; Rosychuk, Rhonda J.

    2012-01-01

    Background Many consumers use natural health products (NHPs) concurrently with prescription medications. As NHP-related harms are under-reported through passive surveillance, the safety of concurrent NHP-drug use remains unknown. To conduct active surveillance in participating community pharmacies to identify adverse events related to concurrent NHP-prescription drug use. Methodology/Principal Findings Participating pharmacists asked individuals collecting prescription medications about (i) concurrent NHP/drug use in the previous three months and (ii) experiences of adverse events. If an adverse event was identified and if the patient provided written consent, a research pharmacist conducted a guided telephone interview to gather additional information after obtaining additional verbal consent and documenting so within the interview form. Over a total of 112 pharmacy weeks, 2615 patients were screened, of which 1037 (39.7%; 95% CI: 37.8% to 41.5%) reported concurrent NHP and prescription medication use. A total of 77 patients reported a possible AE (2.94%; 95% CI: 2.4% to 3.7%), which represents 7.4% of those using NHPs and prescription medications concurrently (95%CI: 6.0% to 9.2%). Of 15 patients available for an interview, 4 (26.7%: 95% CI: 4.3% to 49.0%) reported an AE that was determined to be “probably” due to NHP use. Conclusions/Significance Active surveillance markedly improves identification and reporting of adverse events associated with concurrent NHP-drug use. Although not without challenges, active surveillance is feasible and can generate adverse event data of sufficient quality to allow for meaningful adjudication to assess potential harms. PMID:23028841

  9. Eliciting Production of L2 Target Structures through Priming Activities

    ERIC Educational Resources Information Center

    McDonough, Kim; Trofimovich, Pavel; Neumann, Heike

    2015-01-01

    This study focuses on the pedagogical applications of structural priming research in an English for academic purposes (EAP) context, investigating whether priming activities are an effective tool for eliciting production of target grammatical structures. University students across four EAP classes carried out a total of 6 information-exchange…

  10. Robust morphological detection of sea mines in side-scan sonar images

    NASA Astrophysics Data System (ADS)

    Batman, Sinan; Goutsias, John I.

    2001-10-01

    The automated detection of sea mines remains an increasingly important humanitarian and military task. In recent years, research efforts have been concentrated on developing algorithms that detect mines in complicated littoral environments. Acquired high-resolution side-looking sonar images are often heavily infested with artifacts from natural and man-made clutter. As a consequence, automated detection algorithms, designed for high probability of detection, suffer from a large number of false alarms. To remedy this situation, sophisticated feature extraction and pattern classification techniques are commonly used after detection. In this paper, we propose a nonlinear detection algorithm, based on mathematical morphology, for the robust detection of sea mines. The proposed algorithm is fast and performs well under a variety of sonar modalities and operating conditions. Our approach is based on enhancing potential mine signatures by extracting highlight peaks of appropriate shape and size and by boosting the amplitude of the peaks associated with a potential shadow prior to detection. Signal amplitudes over highlight peaks are extracted using a flat morphological top-hat by reconstruction operator. The contribution of a potential shadow to the detection image is incorporated by increasing the associated highlight amplitude by an amount proportional to the relative contrast between highlight and shadow signatures. The detection image is then thresholded at mid-gray level. The largest p targets from the resulting binary image are then labelled as potential targets. The number of false alarms in the detection image is subsequently reduced to an acceptable level by a feature extraction and classification module. The detection algorithm is tested on two side-scan sonar databases provided by the Coastal Systems Station, Panama City, Florida: SONAR-0 and SONAR-3.

  11. Model-based approach to the detection and classification of mines in sidescan sonar.

    PubMed

    Reed, Scott; Petillot, Yvan; Bell, Judith

    2004-01-10

    This paper presents a model-based approach to mine detection and classification by use of sidescan sonar. Advances in autonomous underwater vehicle technology have increased the interest in automatic target recognition systems in an effort to automate a process that is currently carried out by a human operator. Current automated systems generally require training and thus produce poor results when the test data set is different from the training set. This has led to research into unsupervised systems, which are able to cope with the large variability in conditions and terrains seen in sidescan imagery. The system presented in this paper first detects possible minelike objects using a Markov random field model, which operates well on noisy images, such as sidescan, and allows a priori information to be included through the use of priors. The highlight and shadow regions of the object are then extracted with a cooperating statistical snake, which assumes these regions are statistically separate from the background. Finally, a classification decision is made using Dempster-Shafer theory, where the extracted features are compared with synthetic realizations generated with a sidescan sonar simulator model. Results for the entire process are shown on real sidescan sonar data. Similarities between the sidescan sonar and synthetic aperture radar (SAR) imaging processes ensure that the approach outlined here could be made applied to SAR image analysis.

  12. Model-based approach to the detection and classification of mines in sidescan sonar.

    PubMed

    Reed, Scott; Petillot, Yvan; Bell, Judith

    2004-01-10

    This paper presents a model-based approach to mine detection and classification by use of sidescan sonar. Advances in autonomous underwater vehicle technology have increased the interest in automatic target recognition systems in an effort to automate a process that is currently carried out by a human operator. Current automated systems generally require training and thus produce poor results when the test data set is different from the training set. This has led to research into unsupervised systems, which are able to cope with the large variability in conditions and terrains seen in sidescan imagery. The system presented in this paper first detects possible minelike objects using a Markov random field model, which operates well on noisy images, such as sidescan, and allows a priori information to be included through the use of priors. The highlight and shadow regions of the object are then extracted with a cooperating statistical snake, which assumes these regions are statistically separate from the background. Finally, a classification decision is made using Dempster-Shafer theory, where the extracted features are compared with synthetic realizations generated with a sidescan sonar simulator model. Results for the entire process are shown on real sidescan sonar data. Similarities between the sidescan sonar and synthetic aperture radar (SAR) imaging processes ensure that the approach outlined here could be made applied to SAR image analysis. PMID:14735943

  13. Active helium target: Neutron scalar polarizability extraction via Compton scattering

    SciTech Connect

    Morris, Meg Hornidge, David; Annand, John; Strandberg, Bruno

    2015-12-31

    Precise measurement of the neutron scalar polarizabilities has been a lasting challenge because of the lack of a free-neutron target. Led by the University of Glasgow and the Mount Allison University groups of the A2 collaboration in Mainz, Germany, preparations have begun to test a recent theoretical model with an active helium target with the hope of determining these elusive quantities with small statistical, systematic, and model-dependent errors. Apparatus testing and background-event simulations have been carried out, with the full experiment projected to run in 2015. Once determined, these values can be applied to help understand quantum chromodynamics in the nonperturbative region.

  14. Proteinase-activated receptors (PARs) as targets for antiplatelet therapy.

    PubMed

    Cunningham, Margaret; McIntosh, Kathryn; Bushell, Trevor; Sloan, Graeme; Plevin, Robin

    2016-04-15

    Since the identification of the proteinase-activated receptor (PAR) family as mediators of serine protease activity in the 1990s, there has been tremendous progress in the elucidation of their pathophysiological roles. The development of drugs that target PARs has been the focus of many laboratories for the potential treatment of thrombosis, cancer and other inflammatory diseases. Understanding the mechanisms of PAR activation and G protein signalling pathways evoked in response to the growing list of endogenous proteases has yielded great insight into receptor regulation at the molecular level. This has led to the development of new selective modulators of PAR activity, particularly PAR1. The mixed success of targeting PARs has been best exemplified in the context of inhibiting PAR1 as a new antiplatelet therapy. The development of the competitive PAR1 antagonist, vorapaxar (Zontivity), has clearly shown the value in targeting PAR1 in acute coronary syndrome (ACS); however the severity of associated bleeding with this drug has limited its use in the clinic. Due to the efficacy of thrombin acting via PAR1, strategies to selectively inhibit specific PAR1-mediated G protein signalling pathways or to target the second thrombin platelet receptor, PAR4, are being devised. The rationale behind these alternative approaches is to bias downstream thrombin activity via PARs to allow for inhibition of pro-thrombotic pathways but maintain other pathways that may preserve haemostatic balance and improve bleeding profiles for widespread clinical use. This review summarizes the structural determinants that regulate PARs and the modulators of PAR activity developed to date.

  15. Buoyancy-Activated Cell Sorting Using Targeted Biotinylated Albumin Microbubbles

    PubMed Central

    Liou, Yu-Ren; Wang, Yu-Hsin; Lee, Chia-Ying; Li, Pai-Chi

    2015-01-01

    Cell analysis often requires the isolation of certain cell types. Various isolation methods have been applied to cell sorting, including florescence-activated cell sorting and magnetic-activated cell sorting. However, these conventional approaches involve exerting mechanical forces on the cells, thus risking cell damage. In this study we applied a novel isolation method called buoyancy-activated cell sorting, which involves using biotinylated albumin microbubbles (biotin-MBs) conjugated with antibodies (i.e., targeted biotin-MBs). Albumin MBs are widely used as contrast agents in ultrasound imaging due to their good biocompatibility and stability. For conjugating antibodies, biotin is conjugated onto the albumin MB shell via covalent bonds and the biotinylated antibodies are conjugated using an avidin-biotin system. The albumin microbubbles had a mean diameter of 2μm with a polydispersity index of 0.16. For cell separation, the MDA-MB-231 cells are incubated with the targeted biotin-MBs conjugated with anti-CD44 for 10 min, centrifuged at 10g for 1 min, and then allowed 1 hour at 4°C for separation. The results indicate that targeted biotin-MBs conjugated with anti-CD44 antibodies can be used to separate MDA-MB-231 breast cancer cells; more than 90% of the cells were collected in the MB layer when the ratio of the MBs to cells was higher than 70:1. Furthermore, we found that the separating efficiency was higher for targeted biotin-MBs than for targeted avidin-incorporated albumin MBs (avidin-MBs), which is the most common way to make targeted albumin MBs. We also demonstrated that the recovery rate of targeted biotin-MBs was up to 88% and the sorting purity was higher than 84% for a a heterogenous cell population containing MDA-MB-231 cells (CD44+) and MDA-MB-453 cells (CD44–), which are classified as basal-like breast cancer cells and luminal breast cancer cells, respectively. Knowing that the CD44+ is a commonly used cancer-stem-cell biomarker, our targeted

  16. Heat-activated liposome targeting to streptavidin-coated surfaces.

    PubMed

    Jing, Yujia; Trefná, Hana Dobšíček; Persson, Mikael; Svedhem, Sofia

    2015-06-01

    There is a great need of improved anticancer drugs and corresponding drug carriers. In particular, liposomal drug carriers with heat-activated release and targeting functions are being developed for combined hyperthermia and chemotherapy treatments of tumors. The aim of this study is to demonstrate the heat-activation of liposome targeting to biotinylated surfaces, in model experiments where streptavidin is used as a pretargeting protein. The design of the heat-activated liposomes is based on liposomes assembled in an asymmetric structure and with a defined phase transition temperature. Asymmetry between the inside and the outside of the liposome membrane was generated through the enzymatic action of phospholipase D, where lipid head groups in the outer membrane leaflet, i.e. exposed to the enzyme, were hydrolyzed. The enzymatically treated and purified liposomes did not bind to streptavidin-modified surfaces. When activation heat was applied, starting from 22°C, binding of the liposomes occurred once the temperature approached 33±0.5°C. Moreover, it was observed that the asymmetric structure remained stable for at least 2 weeks. These results show the potential of asymmetric liposomes for the targeted binding to cell membranes in response to (external) temperature stimulus. By using pretargeting proteins, this approach can be further developed for personalized medicine, where tumor-specific antibodies can be selected for the conjugation of pretargeting agents.

  17. Waveguide invariant broadband target detection and reverberation estimation.

    PubMed

    Goldhahn, Ryan; Hickman, Granger; Krolik, Jeffrey

    2008-11-01

    Reverberation often limits the performance of active sonar systems. In particular, backscatter off of a rough ocean floor can obscure target returns and/or large bottom scatterers can be easily confused with water column targets of interest. Conventional active sonar detection involves constant false alarm rate (CFAR) normalization of the reverberation return which does not account for the frequency-selective fading caused by multipath propagation. This paper presents an alternative to conventional reverberation estimation motivated by striations observed in time-frequency analysis of active sonar data. A mathematical model for these reverberation striations is derived using waveguide invariant theory. This model is then used to motivate waveguide invariant reverberation estimation which involves averaging the time-frequency spectrum along these striations. An evaluation of this reverberation estimate using real Mediterranean data is given and its use in a generalized likelihood ratio test based CFAR detector is demonstrated. CFAR detection using waveguide invariant reverberation estimates is shown to outperform conventional cell-averaged and frequency-invariant CFAR detection methods in shallow water environments producing strong reverberation returns which exhibit the described striations.

  18. Interactive sonar-operated device for stereotactic and open surgery.

    PubMed

    Reinhardt, H F; Zweifel, H J

    1990-01-01

    An accuracy of +/- 1 mm in surgical localization of brain targets was reliably attained with a new sonar-operated system, provided that air turbulence was minimized. Since a conventional frame construction with coordinate settings has been disposed of, apart from a halo ring head holder, free access to the operating site is guaranteed. Using offset probes, measurements in depth can be realized with a relatively simple hardware arrangement. A small, 'floating' locator probe can be attached to all kinds of surgical instruments; its spatial position is computed in real time and immediately referred to computed tomography/magnetic resonance imaging scans. Although this work is still in progress, promising applications both in stereotactic and in open surgery are envisaged.

  19. Feasibility study of an active target for the MEG experiment

    NASA Astrophysics Data System (ADS)

    Papa, A.; Cavoto, G.; Ripiccini, E.

    2014-03-01

    We consider the possibility to have an active target for the upgrade of the MEG experiment (MEG II). The active target should work as (1) a beam monitoring, to continuously measure the muon stopping rate and therefore provide a direct evaluation of the detector acceptance (or an absolute normalization of the stopped muon); and as (2) an auxiliary device for the spectrometer, to improve the determination of the muon decay vertex and consequently to achieve a better positron momentum and angular resolutions, detecting the positron from the muon decay. In this work we studied the feasibility of detecting minimum ionizing particle with a single layer of 250 μm fiber and the capability to discriminate between the signal induced by either a muon or a positron.

  20. The Platin-X series: activation, targeting, and delivery.

    PubMed

    Basu, Uttara; Banik, Bhabatosh; Wen, Ru; Pathak, Rakesh K; Dhar, Shanta

    2016-08-16

    Anticancer platinum (Pt) complexes have long been considered to be one of the biggest success stories in the history of medicinal inorganic chemistry. Yet there remains the hunt for the "magic bullet" which can satisfy the requirements of an effective chemotherapeutic drug formulation. Pt(iv) complexes are kinetically more inert than the Pt(ii) congeners and offer the opportunity to append additional functional groups/ligands for prodrug activation, tumor targeting, or drug delivery. The ultimate aim of functionalization is to enhance the tumor selective action and attenuate systemic toxicity of the drugs. Moreover, an increase in cellular accumulation to surmount the resistance of the tumor against the drugs is also of paramount importance in drug development and discovery. In this review, we will address the attempts made in our lab to develop Pt(iv) prodrugs that can be activated and delivered using targeted nanotechnology-based delivery platforms. PMID:27493131

  1. Adjustment of Sonar and Laser Acquisition Data for Building the 3D Reference Model of a Canal Tunnel.

    PubMed

    Moisan, Emmanuel; Charbonnier, Pierre; Foucher, Philippe; Grussenmeyer, Pierre; Guillemin, Samuel; Koehl, Mathieu

    2015-12-11

    In this paper, we focus on the construction of a full 3D model of a canal tunnel by combining terrestrial laser (for its above-water part) and sonar (for its underwater part) scans collected from static acquisitions. The modeling of such a structure is challenging because the sonar device is used in a narrow environment that induces many artifacts. Moreover, the location and the orientation of the sonar device are unknown. In our approach, sonar data are first simultaneously denoised and meshed. Then, above- and under-water point clouds are co-registered to generate directly the full 3D model of the canal tunnel. Faced with the lack of overlap between both models, we introduce a robust algorithm that relies on geometrical entities and partially-immersed targets, which are visible in both the laser and sonar point clouds. A full 3D model, visually promising, of the entrance of a canal tunnel is obtained. The analysis of the method raises several improvement directions that will help with obtaining more accurate models, in a more automated way, in the limits of the involved technology.

  2. Adjustment of Sonar and Laser Acquisition Data for Building the 3D Reference Model of a Canal Tunnel.

    PubMed

    Moisan, Emmanuel; Charbonnier, Pierre; Foucher, Philippe; Grussenmeyer, Pierre; Guillemin, Samuel; Koehl, Mathieu

    2015-01-01

    In this paper, we focus on the construction of a full 3D model of a canal tunnel by combining terrestrial laser (for its above-water part) and sonar (for its underwater part) scans collected from static acquisitions. The modeling of such a structure is challenging because the sonar device is used in a narrow environment that induces many artifacts. Moreover, the location and the orientation of the sonar device are unknown. In our approach, sonar data are first simultaneously denoised and meshed. Then, above- and under-water point clouds are co-registered to generate directly the full 3D model of the canal tunnel. Faced with the lack of overlap between both models, we introduce a robust algorithm that relies on geometrical entities and partially-immersed targets, which are visible in both the laser and sonar point clouds. A full 3D model, visually promising, of the entrance of a canal tunnel is obtained. The analysis of the method raises several improvement directions that will help with obtaining more accurate models, in a more automated way, in the limits of the involved technology. PMID:26690444

  3. Adjustment of Sonar and Laser Acquisition Data for Building the 3D Reference Model of a Canal Tunnel †

    PubMed Central

    Moisan, Emmanuel; Charbonnier, Pierre; Foucher, Philippe; Grussenmeyer, Pierre; Guillemin, Samuel; Koehl, Mathieu

    2015-01-01

    In this paper, we focus on the construction of a full 3D model of a canal tunnel by combining terrestrial laser (for its above-water part) and sonar (for its underwater part) scans collected from static acquisitions. The modeling of such a structure is challenging because the sonar device is used in a narrow environment that induces many artifacts. Moreover, the location and the orientation of the sonar device are unknown. In our approach, sonar data are first simultaneously denoised and meshed. Then, above- and under-water point clouds are co-registered to generate directly the full 3D model of the canal tunnel. Faced with the lack of overlap between both models, we introduce a robust algorithm that relies on geometrical entities and partially-immersed targets, which are visible in both the laser and sonar point clouds. A full 3D model, visually promising, of the entrance of a canal tunnel is obtained. The analysis of the method raises several improvement directions that will help with obtaining more accurate models, in a more automated way, in the limits of the involved technology. PMID:26690444

  4. Transform preprocessing for neural networks for object recogniition and localization with sonar

    NASA Astrophysics Data System (ADS)

    Barshan, Billur; Ayrulu, Birsel

    2003-04-01

    We investigate the pre-processing of sonar signals prior to using neural networks for robust differentiation of commonly encountered features in indoor environments. Amplitude and time-of-flight measurement patterns acquired from a real sonar system are pre-processed using various techniques including wavelet transforms, Fourier and fractional Fourier transforms, and Kohonen's self-organizing feature map. Modular and non-modular neural network structures trained with the back-propagation and generating-shrinking algorithms are used to incorporate learning in the identification of parameter relations for target primitives. Networks trained with the generating-shrinking algorithm demonstrate better generalization and interpolation capability and faster convergence rate. The use of neural networks trained with the back-propagation algorithm, usually with fractional Fourier transform or wavelet pre-processing results in near perfect differentiation, around 85% correct range estimation and around 95% correct azimuth estimation, which would be satisfactory in a wide range of applications. Neural networks can differentiate more targets, employing only a single sensor node, with a higher correct differentiation percentage than achieved with previously reported methods employing multiple sensor nodes. The success of the neural network approach shows that the sonar signals do contain sufficient information to differentiate a considerable number of target types, but the previously reported methods are unable to resolve this identifying information. This work can find application in areas where recognition of patterns hidden in sonar signals is required. Some examples are system control based on acoustic signal detection and identification, map building, navigation, obstacle avoidance, and target-tracking applications for mobile robots and other intelligent systems.

  5. Scanning sonar of rolling porpoises during prey capture dives.

    PubMed

    Akamatsu, T; Wang, D; Wang, K; Li, S; Dong, S

    2010-01-01

    Dolphins and porpoises have excellent biosonar ability, which they use for navigation, ranging and foraging. However, the role of biosonar in free-ranging small cetaceans has not been fully investigated. The biosonar behaviour and body movements of 15 free-ranging finless porpoises (Neophocaena phocaenoides) were observed using electronic tags attached to the animals. The porpoises often rotated their bodies more than 60 deg., on average, around the body axis in a dive bout. This behaviour occupied 31% of the dive duration during 186 h of effective observation time. Rolling dives were associated with extensive searching effort, and 23% of the rolling dive time was phonated, almost twice the phonation ratio of upright dives. Porpoises used short inter-click interval sonar 4.3 times more frequently during rolling dives than during upright dives. Sudden speed drops, which indicated that an individual turned around, occurred 4.5 times more frequently during rolling dives than during upright dives. Together, these data suggest that the porpoises searched extensively for targets and rolled their bodies to enlarge the search area by changing the narrow beam axis of the biosonar. Once a possible target was detected, porpoises frequently produced short-range sonar sounds. Continuous searching for prey and frequent capture trials appeared to occur during rolling dives of finless porpoises. In contrast, head movements ranging +/-2 cm, which can also change the beam axis, were regularly observed during both dives. Head movements might assist in instant assessment of the arbitrary direction by changing the beam axis rather than prey searching and pursuit.

  6. Brain Activation Underlying Threat Detection to Targets of Different Races

    PubMed Central

    Senholzi, Keith B.; Depue, Brendan E.; Correll, Joshua; Banich, Marie T.; Ito, Tiffany A.

    2016-01-01

    The current study examined blood oxygen level dependent (BOLD) signal underlying racial differences in threat detection. During fMRI, participants determined whether pictures of Black or White individuals held weapons. They were instructed to make shoot responses when the picture showed armed individuals but don’t shoot responses to unarmed individuals, with the cost of not shooting armed individuals being greater than that of shooting unarmed individuals. Participants were faster to shoot armed Blacks than Whites, but faster in making don’t shoot responses to unarmed Whites than Blacks. Brain activity differed to armed versus unarmed targets depending on target race, suggesting different mechanisms underlying threat versus safety decisions. Anterior cingulate cortex was preferentially engaged for unarmed Whites than Blacks. Parietal and visual cortical regions exhibited greater activity for armed Blacks than Whites. Seed-based functional connectivity of the amygdala revealed greater coherence with parietal and visual cortices for armed Blacks than Whites. Furthermore, greater implicit Black-danger associations were associated with increased amygdala activation to armed Blacks, compared to armed Whites. Our results suggest that different neural mechanisms may underlie racial differences in responses to armed versus unarmed targets. PMID:26357911

  7. Brain activation underlying threat detection to targets of different races.

    PubMed

    Senholzi, Keith B; Depue, Brendan E; Correll, Joshua; Banich, Marie T; Ito, Tiffany A

    2015-01-01

    The current study examined blood oxygen level-dependent signal underlying racial differences in threat detection. During functional magnetic resonance imaging, participants determined whether pictures of Black or White individuals held weapons. They were instructed to make shoot responses when the picture showed armed individuals but don't shoot responses to unarmed individuals, with the cost of not shooting armed individuals being greater than that of shooting unarmed individuals. Participants were faster to shoot armed Blacks than Whites, but faster in making don't shoot responses to unarmed Whites than Blacks. Brain activity differed to armed versus unarmed targets depending on target race, suggesting different mechanisms underlying threat versus safety decisions. Anterior cingulate cortex was preferentially engaged for unarmed Whites than Blacks. Parietal and visual cortical regions exhibited greater activity for armed Blacks than Whites. Seed-based functional connectivity of the amygdala revealed greater coherence with parietal and visual cortices for armed Blacks than Whites. Furthermore, greater implicit Black-danger associations were associated with increased amygdala activation to armed Blacks, compared to armed Whites. Our results suggest that different neural mechanisms may underlie racial differences in responses to armed versus unarmed targets. PMID:26357911

  8. Active multispectral near-IR detection of small surface targets

    NASA Astrophysics Data System (ADS)

    de Jong, Arie N.; Winkel, Hans; Roos, Marco J. J.

    2001-10-01

    The detection and identification of small surface targets with Electro-Optical sensors is seriously hampered by ground clutter, leading to false alarms and reduced detection probabilities. Active ground illumination can improve the detection performance of EO sensors compared to passive skylight illumination because of the knowledge of the illumination level and of its temporal stability. Sun and sky cannot provide this due to the weather variability. In addition multispectral sensors with carefully chosen spectral bands ranging from the visual into the near IR from 400-2500 nm wavelength can take benefit of a variety of cheap active light sources, ranging from lasers to Xenon or halogen lamps. Results are presented, obtained with a two- color laser scanner with one wavelength in the chlorophyll absorption dip. Another active scanner is described operating at 4 wavebands between 1400 and 2300 nm, using tungsten halogen lamps. Finally a simple TV camera was used with either a ste of narrow band spectral filters or polarization filters in front of the lamps. The targets consisted of an array of mixed objects, most of them real mines. The results how great promise in enhancing the detection and identification probabilities of EO sensors against small surface targets.

  9. Standardization of sonar cephalometry and gestational age.

    PubMed

    Sabbagha, R E; Hughey, M

    1978-10-01

    At present a large number of different charts are used for prediction of gestational age from sonar biparietal diameter (BPD). In this report the reasons for these observed differences are presented. Additionally, the usefulness of all these charts is questioned because a) the mean differences in 7059 BPDs derived by the B-scan from four large fetal population studies are not significantly different from zero and b) BPDs obtained by B scan are statistically comparable to gray-scale or real-time BPDs if medium gain is used. Thus, it is our suggestion that a chart showing the composite mean BPD values of all four studies be used universally for prediction of fetal age. Finally, the guidelines of using sonar BPD as an index of gestational age are presented and the role of the obstetrician in interpreting BPD data is emphasized.

  10. Clutter reduction using Doppler sonar in a harbor environment.

    PubMed

    Yang, T C; Schindall, J; Huang, Chen-Fen; Liu, Jin-Yuan

    2012-11-01

    A high frequency experiment was conducted in the Woods Hole Harbor in Massachusetts to evaluate the effectiveness of Doppler sonar for discriminating targets from reverberation. Using a pulsed linear frequency modulated signal, one finds that the matched filtered outputs are filled with high-level discrete backscattered returns, referred to as clutter, which are often confused with the target echo. The high level non-target returns have an amplitude distribution that is heavy-tailed. Using a Doppler-sensitive binary-phase-shift-keying signal coded with an m-sequence, the target echo and clutter can be separated by Doppler and delay, and tracked using the Doppler spectrogram (Dopplergram). The Doppler filtered time series show a background reverberation with a Rayleigh-like amplitude distribution, with an improved signal-to-(peak) reverberation ratio compared with that without Doppler filtering. The reduced reverberation level with Doppler processing decreases the probability of false alarm (Pfa) for a given threshold level. Conversely, for a given Pfa, the higher signal-to-(peak) reverberation ratio implies a higher probability of detection. Transmission loss measurement was conducted to estimate some of the system parameters, e.g., the source level and target strength relative to the noise level.

  11. Sonar Signals of the Sea Lion.

    PubMed

    Poulter, T C

    1963-02-22

    Tape recordings were made of the underwater noises of captive sea lions swimming in a concrete pool at night. When approaching pieces of fish that were thrown into the water, the sea lions emitted trains of sound signals like those of the bat and the porpoise. A detailed analysis of these noises shows that they meet the criteria of a pulse-modulated sonar system and, in fact, reveal an amazing sophistication so far as echo ranging is concerned. PMID:17829121

  12. Sonar Signals of the Sea Lion.

    PubMed

    Poulter, T C

    1963-02-22

    Tape recordings were made of the underwater noises of captive sea lions swimming in a concrete pool at night. When approaching pieces of fish that were thrown into the water, the sea lions emitted trains of sound signals like those of the bat and the porpoise. A detailed analysis of these noises shows that they meet the criteria of a pulse-modulated sonar system and, in fact, reveal an amazing sophistication so far as echo ranging is concerned.

  13. Mapping with side-scan sonar

    SciTech Connect

    Prior, D.B.; Coleman, J.M.; Roberts, H.H.

    1981-04-01

    The use of sideways scanning sonar as a technique for detailed sea-floor mapping is described in this article. Sea-floor mapping of the continental shelf is becoming increasingly necessary for the development of oil and gas resources. More recently attempts are being made to extend the survey capabilities to deeper water shelf margins, slopes, and basins. Conventional systems, digital systems, survey ranges, data processing, mosaics, and applications are discussed. (DMC)

  14. Sonar Sensor Models and Their Application to Mobile Robot Localization

    PubMed Central

    Burguera, Antoni; González, Yolanda; Oliver, Gabriel

    2009-01-01

    This paper presents a novel approach to mobile robot localization using sonar sensors. This approach is based on the use of particle filters. Each particle is augmented with local environment information which is updated during the mission execution. An experimental characterization of the sonar sensors used is provided in the paper. A probabilistic measurement model that takes into account the sonar uncertainties is defined according to the experimental characterization. The experimental results quantitatively evaluate the presented approach and provide a comparison with other localization strategies based on both the sonar and the laser. Some qualitative results are also provided for visual inspection. PMID:22303171

  15. Sonar sensor models and their application to mobile robot localization.

    PubMed

    Burguera, Antoni; González, Yolanda; Oliver, Gabriel

    2009-01-01

    This paper presents a novel approach to mobile robot localization using sonar sensors. This approach is based on the use of particle filters. Each particle is augmented with local environment information which is updated during the mission execution. An experimental characterization of the sonar sensors used is provided in the paper. A probabilistic measurement model that takes into account the sonar uncertainties is defined according to the experimental characterization. The experimental results quantitatively evaluate the presented approach and provide a comparison with other localization strategies based on both the sonar and the laser. Some qualitative results are also provided for visual inspection.

  16. The sonar aperture and its neural representation in bats.

    PubMed

    Heinrich, Melina; Warmbold, Alexander; Hoffmann, Susanne; Firzlaff, Uwe; Wiegrebe, Lutz

    2011-10-26

    As opposed to visual imaging, biosonar imaging of spatial object properties represents a challenge for the auditory system because its sensory epithelium is not arranged along space axes. For echolocating bats, object width is encoded by the amplitude of its echo (echo intensity) but also by the naturally covarying spread of angles of incidence from which the echoes impinge on the bat's ears (sonar aperture). It is unclear whether bats use the echo intensity and/or the sonar aperture to estimate an object's width. We addressed this question in a combined psychophysical and electrophysiological approach. In three virtual-object playback experiments, bats of the species Phyllostomus discolor had to discriminate simple reflections of their own echolocation calls differing in echo intensity, sonar aperture, or both. Discrimination performance for objects with physically correct covariation of sonar aperture and echo intensity ("object width") did not differ from discrimination performances when only the sonar aperture was varied. Thus, the bats were able to detect changes in object width in the absence of intensity cues. The psychophysical results are reflected in the responses of a population of units in the auditory midbrain and cortex that responded strongest to echoes from objects with a specific sonar aperture, regardless of variations in echo intensity. Neurometric functions obtained from cortical units encoding the sonar aperture are sufficient to explain the behavioral performance of the bats. These current data show that the sonar aperture is a behaviorally relevant and reliably encoded cue for object size in bat sonar.

  17. Measurement of stream channel habitat using sonar

    USGS Publications Warehouse

    Flug, M.; Seitz, H.; Scott, J.

    1998-01-01

    An efficient and low cost technique using a sonar system was evaluated for describing channel geometry and quantifying inundated area in a large river. The boat-mounted portable sonar equipment was used to record water depths and river width measurements for direct storage on a laptop computer. The field data collected from repeated traverses at a cross-section were evaluated to determine the precision of the system and field technique. Results from validation at two different sites showed average sample standard deviations (S.D.s) of 0.12 m for these complete cross-sections, with coefficient of variations of 10%. Validation using only the mid-channel river cross-section data yields an average sample S.D. of 0.05 m, with a coefficient of variation below 5%, at a stable and gauged river site using only measurements of water depths greater than 0.6 m. Accuracy of the sonar system was evaluated by comparison to traditionally surveyed transect data from a regularly gauged site. We observed an average mean squared deviation of 46.0 cm2, considering only that portion of the cross-section inundated by more than 0.6 m of water. Our procedure proved to be a reliable, accurate, safe, quick, and economic method to record river depths, discharges, bed conditions, and substratum composition necessary for stream habitat studies. ?? 1998 John Wiley & Sons, Ltd.

  18. Human Face Classification Using Ultrasonic Sonar Imaging

    NASA Astrophysics Data System (ADS)

    Miao, Zhenwei; Ji, Wei; Xu, Yong; Yang, Jun

    2009-07-01

    In this paper, human face classification using ultrasonic sonar imaging is investigated. On the basis of Freedman's “image pulse” model, the scattering centers model is employed to simplify the complex geometry of the human face into a series of scattering centers. A chirp signal is utilized to detect the human face for its high range resolution and large signal-to-noise ratio. Ultrasonic sonar images, also named high-resolution range profiles, are obtained by demodulating the echoes with a reference chirp signal. Features directly related to the geometry of the human face are extracted from ultrasonic sonar images and verified in the experiments designed with different configurations of transmitter-receiver (TR) pairs. Experimental results indicate that the improved feature extraction method can achieve a high recognition rate of over 99% in the case of ultrasonic transmitters angled at 45° above and orthogonal to the face, and this method improves the performance of ultrasonic face recognition compared with our previous result.

  19. Radar and sonar probing of rocks

    SciTech Connect

    Unterberger, R.R.

    1983-03-01

    The purpose of this paper is to summarize the research of the past sixteen years on methods of probing into solid rock. For these purposes, there are three completely different systems: radar, sonar, and nonlinear sonar. In dry salt all of the systems work. Five radar systems of different frequencies have been used to probe salt for different purposes and with different resolutions. Distances penetrated were from almost 2000 meters to under one 1 meter. With some moisture in the rock, the low frequency Alpha radar system is best because it operates at the frequency of the minimum in loss tangent for water. Sonar systems are used for even more water in the rock. Ranges of one to 300 meters have been obtained in salt with the lower ranges (to 100m) being obtainable is salt with the most water in it. Using one or more of the probing systems, the authors have detected, and ranged to, salt dome flanks, the top of salt, sandstone, anhydrite and sylvite stringers in salt, fractures in salt and water-filled fractures. We have also detected old boreholes in salt pillars, and measured the range and direction to them.

  20. Mid-water Software Tools and the Application to Processing and Analysis of the Latest Generation Multibeam Sonars

    NASA Astrophysics Data System (ADS)

    Gee, L.; Doucet, M.

    2010-12-01

    The latest generation of multibeam sonars now has the ability to map the water-column, along with the seafloor. Currently, the users of these sonars have a limited view of the mid-water data in real-time, and if they do store the data, they are restricted to replaying it only, with no ability for further analysis. The water-column data has the potential to address a number of research areas including detection of small targets (wrecks, etc.) above the seabed, mapping of fish and marine mammals and a wide range of physical oceanographic processes. However, researchers have been required to develop their own in-house software tools before they can even begin their study of the water column data. This paper describes the development of more general software tools for the full processing of raw sonar data (bathymetry, backscatter and water-column) to yield output products suitable for visualization in a 4D time-synchronized environment. The huge water-column data volumes generated by the new sonars, combined with the variety of data formats from the different sonar manufacturers, provides a significant challenge in the design and development of tools that can be applied to the wide variety of applications. The development of the mid-water tools on this project addressed this problem by using a unified way of storing the water column data in a generic water column format (GWC). The sonar data are converted into the GWC by re-integrating the water column packets with time-based navigation and attitude, such that downstream in the workflow, the tools will have access to all relevant data of any particular ping. Dependent on the application and the resolution requirements, the conversion process also allows simple sub-sampling. Additionally, each file is indexed to enable fast non-linear lookup and extraction of any packet type or packet type collection in the sonar file. These tools also fully exploit multi-core and hyper-threading technologies to maximize the throughput

  1. Factor XI and Contact Activation as Targets for Antithrombotic Therapy

    PubMed Central

    Gailani, David; Bane, Charles E.; Gruber, Andras

    2015-01-01

    Summary The most commonly used anticoagulants produce therapeutic antithrombotic effects either by inhibiting thrombin or factor Xa, or by lowering the plasma levels of the precursors of these key enzymes, prothrombin and factor X. These drugs do not distinguish between thrombin generation contributing to thrombosis from thrombin generation required for hemostasis. Thus, anticoagulants increase bleeding risk, and many patients who would benefit from therapy go untreated because of comorbidities that place them at unacceptable risk for hemorrhage. Studies in animals demonstrate that components of the plasma contact activation system contribute to experimentally-induced thrombosis, despite playing little or no role in hemostasis. Attention has focused on factor XII, the zymogen of a protease (factor XIIa) that initiates contact activation when blood is exposed to foreign surfaces; and factor XI, the zymogen of the protease factor XIa, which links contact activation to the thrombin generation mechanism. In the case of factor XI, epidemiologic data indicate this protein contributes to stroke and venous thromboembolism, and perhaps myocardial infarction, in humans. A phase 2 trial showing that reduction of factor XI may be more effective than low-molecular-weight heparin at preventing venous thrombosis during knee replacement surgery provides proof of concept for the premise that an antithrombotic effect can be uncoupled from an anticoagulant effect in humans by targeting components of contact activation. Here we review data on the role of factor XI and factor XII in thrombosis, and results of pre-clinical and human trials for therapies targeting these proteins. PMID:25976012

  2. HER2 activating mutations are targets for colorectal cancer treatment

    PubMed Central

    Kavuri, Shyam M.; Jain, Naveen; Galimi, Francesco; Cottino, Francesca; Leto, Simonetta M.; Migliardi, Giorgia; Searleman, Adam C.; Shen, Wei; Monsey, John; Trusolino, Livio; Jacobs, Samuel A.; Bertotti, Andrea; Bose, Ron

    2015-01-01

    The Cancer Genome Atlas project identified HER2 somatic mutations and gene amplification in 7% of colorectal cancer patients. Introduction of the HER2 mutations, S310F, L755S, V777L, V842I, and L866M, into colon epithelial cells increased signaling pathways and anchorage-independent cell growth, indicating that they are activating mutations. Introduction of these HER2 activating mutations into colorectal cancer cell lines produced resistance to cetuximab and panitumumab by sustaining MAPK phosphorylation. HER2 mutations are potently inhibited by low nanomolar doses of the irreversible tyrosine kinase inhibitors, neratinib and afatinib. HER2 gene sequencing of 48 cetuximab resistant, quadruple (KRAS, NRAS, BRAF, and PIK3CA) WT colorectal cancer patient-derived xenografts (PDX’s) identified 4 PDX’s with HER2 mutations. HER2 targeted therapies were tested on two PDX’s. Treatment with a single HER2 targeted drug (trastuzumab, neratinib, or lapatinib) delayed tumor growth, but dual HER2 targeted therapy with trastuzumab plus tyrosine kinase inhibitors produced regression of these HER2 mutated PDX’s. PMID:26243863

  3. 50 CFR 216.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... incidental to the following activities: (1) The use of the following mid-frequency active sonar (MFAS) and high frequency active sonar (HFAS) sources, or similar sources, for Navy training activities (estimated amounts below): (1) The use of the following mid-frequency active sonar (MFAS) and high frequency...

  4. 50 CFR 216.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... incidental to the following activities: (1) The use of the following mid-frequency active sonar (MFAS) and high frequency active sonar (HFAS) sources, or similar sources, for Navy training activities (estimated amounts below): (1) The use of the following mid-frequency active sonar (MFAS) and high frequency...

  5. Haem-activated promiscuous targeting of artemisinin in Plasmodium falciparum

    PubMed Central

    Wang, Jigang; Zhang, Chong-Jing; Chia, Wan Ni; Loh, Cheryl C. Y.; Li, Zhengjun; Lee, Yew Mun; He, Yingke; Yuan, Li-Xia; Lim, Teck Kwang; Liu, Min; Liew, Chin Xia; Lee, Yan Quan; Zhang, Jianbin; Lu, Nianci; Lim, Chwee Teck; Hua, Zi-Chun; Liu, Bin; Shen, Han-Ming; Tan, Kevin S. W.; Lin, Qingsong

    2015-01-01

    The mechanism of action of artemisinin and its derivatives, the most potent of the anti-malarial drugs, is not completely understood. Here we present an unbiased chemical proteomics analysis to directly explore this mechanism in Plasmodium falciparum. We use an alkyne-tagged artemisinin analogue coupled with biotin to identify 124 artemisinin covalent binding protein targets, many of which are involved in the essential biological processes of the parasite. Such a broad targeting spectrum disrupts the biochemical landscape of the parasite and causes its death. Furthermore, using alkyne-tagged artemisinin coupled with a fluorescent dye to monitor protein binding, we show that haem, rather than free ferrous iron, is predominantly responsible for artemisinin activation. The haem derives primarily from the parasite's haem biosynthesis pathway at the early ring stage and from haemoglobin digestion at the latter stages. Our results support a unifying model to explain the action and specificity of artemisinin in parasite killing. PMID:26694030

  6. Haem-activated promiscuous targeting of artemisinin in Plasmodium falciparum.

    PubMed

    Wang, Jigang; Zhang, Chong-Jing; Chia, Wan Ni; Loh, Cheryl C Y; Li, Zhengjun; Lee, Yew Mun; He, Yingke; Yuan, Li-Xia; Lim, Teck Kwang; Liu, Min; Liew, Chin Xia; Lee, Yan Quan; Zhang, Jianbin; Lu, Nianci; Lim, Chwee Teck; Hua, Zi-Chun; Liu, Bin; Shen, Han-Ming; Tan, Kevin S W; Lin, Qingsong

    2015-01-01

    The mechanism of action of artemisinin and its derivatives, the most potent of the anti-malarial drugs, is not completely understood. Here we present an unbiased chemical proteomics analysis to directly explore this mechanism in Plasmodium falciparum. We use an alkyne-tagged artemisinin analogue coupled with biotin to identify 124 artemisinin covalent binding protein targets, many of which are involved in the essential biological processes of the parasite. Such a broad targeting spectrum disrupts the biochemical landscape of the parasite and causes its death. Furthermore, using alkyne-tagged artemisinin coupled with a fluorescent dye to monitor protein binding, we show that haem, rather than free ferrous iron, is predominantly responsible for artemisinin activation. The haem derives primarily from the parasite's haem biosynthesis pathway at the early ring stage and from haemoglobin digestion at the latter stages. Our results support a unifying model to explain the action and specificity of artemisinin in parasite killing. PMID:26694030

  7. Calcium-Activated Potassium Channels: Potential Target for Cardiovascular Diseases.

    PubMed

    Dong, De-Li; Bai, Yun-Long; Cai, Ben-Zhi

    2016-01-01

    Ca(2+)-activated K(+) channels (KCa) are classified into three subtypes: big conductance (BKCa), intermediate conductance (IKCa), and small conductance (SKCa) KCa channels. The three types of KCa channels have distinct physiological or pathological functions in cardiovascular system. BKCa channels are mainly expressed in vascular smooth muscle cells (VSMCs) and inner mitochondrial membrane of cardiomyocytes, activation of BKCa channels in these locations results in vasodilation and cardioprotection against cardiac ischemia. IKCa channels are expressed in VSMCs, endothelial cells, and cardiac fibroblasts and involved in vascular smooth muscle proliferation, migration, vessel dilation, and cardiac fibrosis. SKCa channels are widely expressed in nervous and cardiovascular system, and activation of SKCa channels mainly contributes membrane hyperpolarization. In this chapter, we summarize the physiological and pathological roles of the three types of KCa channels in cardiovascular system and put forward the possibility of KCa channels as potential target for cardiovascular diseases.

  8. Utilization of a BGO detector as an active oxygen target

    NASA Astrophysics Data System (ADS)

    Loveman, R.; Gozani, T.; Bendahan, J.; Krivicich, J.; Elias, E.; Altschuler, E.

    1994-12-01

    The (n, n'γx) cross section for the 6.13 MeV state in oxygen has recently become of general interest because of the possibility of using this process to assay oxygen as a part of non-intrusive inspections. Localized densities of carbon, oxygen, and nitrogen are particularly useful in determining the presence of explosives and/or drugs in containers of all sizes, from suitcases to cargo containers. The presence of oxygen in BGO (Bi 4Ge 3O 12) scintillator makes this detector suitable for use as an active target for the measurement of the energy dependence of the excitation, of the first (6.049 MeV O +) and second (6.130 MeV 3 -) excited states in 16O by fast neutron interactions. An active target functions as both a target and an active device such as a detector. The de-excitations of the 6.049 and 6.130 states take place by nuclear pair production and γ-ray emission respectively. There is a large probability of absorbing all of the de-excitation energy in the scintillator in either of these cases. Since the energies deposited in the scintillator by these transitions are very close, the de-excitations are indistinguishable. However, since the cross section for the excitation of the 6.13 MeV state is believed to be larger than that of the 6.049 MeV, the major measured features of the energy variations are those related to the second state. The validity of the technique was initially tested using (MCNP) calculations. The calculations established that the detected neutron count rate in the crystal was proportional to the cross-sections used as input for the calculations, and that the constant of proportionality did not vary with neutron energy. Subsequently, measurements were made with a BGO detector as an active oxygen target. The results clearly show a strong energy dependence including several resonances.

  9. Activity based chemical proteomics: profiling proteases as drug targets.

    PubMed

    Heal, William Percy; Wickramasinghe, Sasala Roshinie; Tate, Edward William

    2008-09-01

    The pivotal role of proteases in many diseases has generated considerable interest in their basic biology, and in the potential to target them for chemotherapy. Although fundamental to the initiation and progression of diseases such as cancer, diabetes, arthritis and malaria, in many cases their precise role remains unknown. Activity-based chemical proteomics-an emerging field involving a combination of organic synthesis, biochemistry, cell biology, biophysics and bioinformatics-allows the detection, visualisation and activity quantification of whole families or selected sub-sets of proteases based upon their substrate specificity. This approach can be applied for drug target/lead identification and validation, the fundamentals of drug discovery. The activity-based probes discussed in this review contain three key features; a 'warhead' (binds irreversibly but selectively to the active site), a 'tag' (allowing enzyme 'handling', with a combination of fluorescent, affinity and/or radio labels), and a linker region between warhead and tag. From the design and synthesis of the linker arise some of the latest developments discussed here; not only can the physical properties (e.g., solubility, localisation) of the probe be tuned, but the inclusion of a cleavable moiety allows selective removal of tagged enzyme from affinity beads etc. The design and synthesis of recently reported probes is discussed, including modular assembly of highly versatile probes via solid phase synthesis. Recent applications of activity-based protein profiling to specific proteases (serine, threonine, cysteine and metalloproteases) are reviewed as are demonstrations of their use in the study of disease function in cancer and malaria.

  10. Simulations of multi-beam sonar echos from schooling individual fish in a quiet environment.

    PubMed

    Holmin, Arne Johannes; Handegard, Nils Olav; Korneliussen, Rolf J; Tjøstheim, Dag

    2012-12-01

    A model is developed and demonstrated for simulating echosounder and sonar observations of fish schools with specified shapes and composed of individuals having specified target strengths and behaviors. The model emulates the performances of actual multi-frequency echosounders and multi-beam echosounders and sonars and generates synthetic echograms of fish schools that can be compared with real echograms. The model enables acoustic observations of large in situ fish schools to be evaluated in terms of individual and aggregated fish behaviors. It also facilitates analyses of the sensitivity of fish biomass estimates to different target strength models and their parameterizations. To demonstrate how this tool may facilitate objective interpretations of acoustically estimated fish biomass and behavior, simulated echograms of fish with different spatial and orientation distributions are compared with real echograms of herring collected with a multi-beam sonar aboard the research vessel "G.O. Sars." Results highlight the important effects of fish-backscatter directivity, particularly when sensing with small acoustic wavelengths relative to the fish length. Results also show that directivity is both a potential obstacle to estimating fish biomass accurately and a potential source of information about fish behavior.

  11. Development of a fresh-water tank facility for calibrating multibeam sonar

    NASA Astrophysics Data System (ADS)

    Baldwin, Kenneth C.; Mayer, Larry; McLeod, Andrew; Foote, Kenneth G.; Chu, Dezhang; Beaudoin, Jonathan; Weber, Tom

    2003-10-01

    Multibeam sonars are being used increasingly to image fish. To realize their quantitative potential for measuring the numerical density of fish and other aquatic organisms, it is essential that they be calibrated. This can be done by the use of standard targets or reference hydrophones. The calibration of narrow beam acoustic arrays requires precision angular positioning of the transducer under test. This precision is defined as 0.1 deg of angular position control. This degree of control is achievable with the use of a precision rotary table typically used in CNC machining. This presentation describes: system specifications and the LABVIEW program used to control and coordinate position and acoustic data acquisition, the initial evaluation of the rotary table for repeatability and possible backlash, and representative acoustic measurements made with multibeam sonars using the new system. [Work supported by NSF Contract No. OCE 0002842.

  12. Clutter suppression and classification using twin inverted pulse sonar in ship wakes.

    PubMed

    Leighton, T G; Finfer, D C; Chua, G H; White, P R; Dix, J K

    2011-11-01

    Twin inverted pulse sonar (TWIPS) is here deployed in the wake of a moored rigid inflatable boat (RIB) with propeller turning, and then in the wake of a moving tanker of 4580 dry weight tonnage (the Whitchallenger). This is done first to test its ability to distinguish between scatter from the wake and scatter from the seabed, and second to test its ability to improve detectability of the seabed through the wake, compared to conventional sonar processing techniques. TWIPS does this by distinguishing between linear and nonlinear scatterers and has the further property of distinguishing those nonlinear targets which scatter energy at the even-powered harmonics from those which scatter in the odd-powered harmonics. TWIPS can also, in some manifestations, require no range correction (and therefore does not require the a priori environment knowledge necessary for most remote detection technologies).

  13. Echolocation in bats: signal processing of echoes for target range.

    PubMed

    Simmons, J A

    1971-03-01

    Echolocating bats Eptesicus fuscus and Phyllostomus hastatus can discriminate between the nearer and farther of two targets. Their errors in discrimination are predicted accurately by the autocorrelation functions of their sonar cries. These bats behave as though they have an ideal sonar system which cross correlates the transmitted cry with the returning echo to extract targetrange information.

  14. A Deterministic Approach to Active Debris Removal Target Selection

    NASA Astrophysics Data System (ADS)

    Lidtke, A.; Lewis, H.; Armellin, R.

    2014-09-01

    Many decisions, with widespread economic, political and legal consequences, are being considered based on space debris simulations that show that Active Debris Removal (ADR) may be necessary as the concerns about the sustainability of spaceflight are increasing. The debris environment predictions are based on low-accuracy ephemerides and propagators. This raises doubts about the accuracy of those prognoses themselves but also the potential ADR target-lists that are produced. Target selection is considered highly important as removal of many objects will increase the overall mission cost. Selecting the most-likely candidates as soon as possible would be desirable as it would enable accurate mission design and allow thorough evaluation of in-orbit validations, which are likely to occur in the near-future, before any large investments are made and implementations realized. One of the primary factors that should be used in ADR target selection is the accumulated collision probability of every object. A conjunction detection algorithm, based on the smart sieve method, has been developed. Another algorithm is then applied to the found conjunctions to compute the maximum and true probabilities of collisions taking place. The entire framework has been verified against the Conjunction Analysis Tools in AGIs Systems Toolkit and relative probability error smaller than 1.5% has been achieved in the final maximum collision probability. Two target-lists are produced based on the ranking of the objects according to the probability they will take part in any collision over the simulated time window. These probabilities are computed using the maximum probability approach, that is time-invariant, and estimates of the true collision probability that were computed with covariance information. The top-priority targets are compared, and the impacts of the data accuracy and its decay are highlighted. General conclusions regarding the importance of Space Surveillance and Tracking for the

  15. Processing of SeaMARC swath sonar imagery

    SciTech Connect

    Pratson, L.; Malinverno, A.; Edwards, M.; Ryan, W. )

    1990-05-01

    Side-scan swath sonar systems have become an increasingly important means of mapping the sea floor. Two such systems are the deep-towed, high-resolution SeaMARC I sonar, which has a variable swath width of up to 5 km, and the shallow-towed, lower-resolution SeaMARC II sonar, which has a swath width of 10 km. The sea-floor imagery of acoustic backscatter output by the SeaMARC sonars is analogous to aerial photographs and airborne side-looking radar images of continental topography. Geologic interpretation of the sea-floor imagery is greatly facilitated by image processing. Image processing of the digital backscatter data involves removal of noise by median filtering, spatial filtering to remove sonar scans of anomalous intensity, across-track corrections to remove beam patterns caused by nonuniform response of the sonar transducers to changes in incident angle, and contrast enhancement by histogram equalization to maximize the available dynamic range. Correct geologic interpretation requires submarine structural fabrics to be displayed in their proper locations and orientations. Geographic projection of sea-floor imagery is achieved by merging the enhanced imagery with the sonar vehicle navigation and correcting for vehicle attitude. Co-registration of bathymetry with sonar imagery introduces sea-floor relief and permits the imagery to be displayed in three-dimensional perspectives, furthering the ability of the marine geologist to infer the processes shaping formerly hidden subsea terrains.

  16. 50 CFR 216.240 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Active Sonar Training (AFAST) § 216.240 Specified activity and specified geographical region. (a... Navy is only authorized if it occurs incidental to the use of the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources, explosive sonobuoys, or similar sources,...

  17. 50 CFR 216.240 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Active Sonar Training (AFAST) § 216.240 Specified activity and specified geographical region. (a... Navy is only authorized if it occurs incidental to the use of the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources, explosive sonobuoys, or similar sources,...

  18. 50 CFR 216.240 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Active Sonar Training (AFAST) § 216.240 Specified activity and specified geographical region. (a... Navy is only authorized if it occurs incidental to the use of the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources, explosive sonobuoys, or similar sources,...

  19. Small Molecule Inhibitors Targeting Activator Protein 1 (AP-1)

    PubMed Central

    2015-01-01

    Activator protein 1 (AP-1) is a pivotal transcription factor that regulates a wide range of cellular processes including proliferation, apoptosis, differentiation, survival, cell migration, and transformation. Accumulating evidence supports that AP-1 plays an important role in several severe disorders including cancer, fibrosis, and organ injury, as well as inflammatory disorders such as asthma, psoriasis, and rheumatoid arthritis. AP-1 has emerged as an actively pursued drug discovery target over the past decade. Excitingly, a selective AP-1 inhibitor T-5224 (51) has been investigated in phase II human clinical trials. Nevertheless, no effective AP-1 inhibitors have yet been approved for clinical use. Despite significant advances achieved in understanding AP-1 biology and function, as well as the identification of small molecules modulating AP-1 associated signaling pathways, medicinal chemistry efforts remain an urgent need to yield selective and efficacious AP-1 inhibitors as a viable therapeutic strategy for human diseases. PMID:24831826

  20. Semiconducting Polymer Nanobioconjugates for Targeted Photothermal Activation of Neurons.

    PubMed

    Lyu, Yan; Xie, Chen; Chechetka, Svetlana A; Miyako, Eijiro; Pu, Kanyi

    2016-07-27

    Optogenetics provides powerful means for precise control of neuronal activity; however, the requirement of transgenesis and the incapability to extend the neuron excitation window into the deep-tissue-penetrating near-infrared (NIR) region partially limit its application. We herein report a potential alternative approach to optogenetics using semiconducting polymer nanobioconjugates (SPNsbc) as the photothermal nanomodulator to control the thermosensitive ion channels in neurons. SPNsbc are designed to efficiently absorb the NIR light at 808 nm and have a photothermal conversion efficiency higher than that of gold nanorods. By virtue of the fast heating capability in conjunction with the precise targeting to the thermosensitive ion channel, SPNsbc can specifically and rapidly activate the intracellular Ca(2+) influx of neuronal cells in a reversible and safe manner. Our study provides an organic nanoparticle based strategy that eliminates the need for genetic transfection to remotely regulate cellular machinery. PMID:27404507

  1. Novel strategies for ultrahigh specific activity targeted nanoparticles

    SciTech Connect

    Zhou, Dong

    2012-12-13

    We have developed novel strategies optimized for preparing high specific activity radiolabeled nanoparticles, targeting nuclear imaging of low abundance biomarkers. Several compounds have been labeled with F-18 and Cu-64 for radiolabeling of SCK-nanoparticles via Copper(I) catalyzed or copper-free alkyne-azide cyclolization. Novel strategies have been developed to achieve ultrahigh specific activity with administrable amount of dose for human study using copper-free chemistry. Ligands for carbonic anhydrase 12 (CA12), a low abundance extracellular biomarker for the responsiveness of breast cancer to endocrine therapie, have been labeled with F-18 and Cu-64, and one of them has been evaluated in animal models. The results of this project will lead to major improvements in the use of nanoparticles in nuclear imaging and will significantly advance their potential for detecting low abundance biomarkers of medical importance.

  2. Experimental observations of active invariance striations in a tank environment.

    PubMed

    Quijano, Jorge E; Campbell, Richard L; Oesterlein, Tobias G; Zurk, Lisa M

    2010-08-01

    The waveguide invariant in shallow water environments has been widely studied in the context of passive sonar. The invariant provides a relationship between the frequency content of a moving broadband source and the distance to the receiver, and this relationship is not strongly affected by small perturbations in environment parameters such as sound speed or bottom features. Recent experiments in shallow water suggest that a similar range-frequency structure manifested as striations in the spectrogram exists for active sonar, and this property has the potential to enhance the performance of target tracking algorithms. Nevertheless, field experiments with active sonar have not been conclusive on how the invariant is affected by the scattering kernel of the target and the sonar configuration (monostatic vs bistatic). The experimental work presented in this paper addresses those issues by showing the active invariance for known scatterers under controlled conditions of bathymetry, sound speed profile and high SNR. Quantification of the results is achieved by introducing an automatic image processing approach inspired on the Hough transform for extraction of the invariant from spectrograms. Normal mode simulations are shown to be in agreement with the experimental results. PMID:20707430

  3. Experimental observations of active invariance striations in a tank environment.

    PubMed

    Quijano, Jorge E; Campbell, Richard L; Oesterlein, Tobias G; Zurk, Lisa M

    2010-08-01

    The waveguide invariant in shallow water environments has been widely studied in the context of passive sonar. The invariant provides a relationship between the frequency content of a moving broadband source and the distance to the receiver, and this relationship is not strongly affected by small perturbations in environment parameters such as sound speed or bottom features. Recent experiments in shallow water suggest that a similar range-frequency structure manifested as striations in the spectrogram exists for active sonar, and this property has the potential to enhance the performance of target tracking algorithms. Nevertheless, field experiments with active sonar have not been conclusive on how the invariant is affected by the scattering kernel of the target and the sonar configuration (monostatic vs bistatic). The experimental work presented in this paper addresses those issues by showing the active invariance for known scatterers under controlled conditions of bathymetry, sound speed profile and high SNR. Quantification of the results is achieved by introducing an automatic image processing approach inspired on the Hough transform for extraction of the invariant from spectrograms. Normal mode simulations are shown to be in agreement with the experimental results.

  4. Offshore exploration and platform siting by imaging Sonar

    SciTech Connect

    Feder, A.M.

    1986-03-17

    Sonar, an acronym for sonic azimuth and ranging (some say ''sonic detection and ranging''), is the name of a type of remote sensor that was developed in World War II for antisubmarine warfare purposes. The principles of the sensor system are simple in that it broadcasts a focused (shaped) sonic pulse through the water (transmission medium), then receives the echo of that pulse and processes this signal for its information content. Hence, Sonar system principles are highly analagous to those of radar. Post-World War II saw development of Sonar probes that provided some success in determining sea floor materials composition and condition (e.g., subbottom profilers). The major advance, however, was with the advent of digital computation systems. These permitted the coupling of Sonar azimuth and range components to provide ''x'' and ''y'' coordinates for each echo location, or ''z'' value. This advance is seeing a proliferation of different types of imaging Sonar systems and performances.

  5. Detecting Atlantic herring by parametric sonar.

    PubMed

    Godo, Olav Rune; Foote, Kenneth G; Dybedal, Johnny; Tenningen, Eirik; Patel, Ruben

    2010-04-01

    The difference-frequency band of the Kongsberg TOPAS PS18 parametric sub-bottom profiling sonar, nominally 1-6 kHz, is being used to observe Atlantic herring. Representative TOPAS echograms of herring layers and schools observed in situ in December 2008 and November 2009 are presented. These agree well with echograms of volume backscattering strength derived simultaneously with the narrowband Simrad EK60/18- and 38-kHz scientific echo sounder, also giving insight into herring avoidance behavior in relation to survey vessel passage. Progress in rendering the TOPAS echograms quantitative is described. PMID:20369983

  6. Detecting Atlantic herring by parametric sonar.

    PubMed

    Godo, Olav Rune; Foote, Kenneth G; Dybedal, Johnny; Tenningen, Eirik; Patel, Ruben

    2010-04-01

    The difference-frequency band of the Kongsberg TOPAS PS18 parametric sub-bottom profiling sonar, nominally 1-6 kHz, is being used to observe Atlantic herring. Representative TOPAS echograms of herring layers and schools observed in situ in December 2008 and November 2009 are presented. These agree well with echograms of volume backscattering strength derived simultaneously with the narrowband Simrad EK60/18- and 38-kHz scientific echo sounder, also giving insight into herring avoidance behavior in relation to survey vessel passage. Progress in rendering the TOPAS echograms quantitative is described.

  7. Mechanical charactization of sonar window materials

    SciTech Connect

    DeTeresa, S.J.; Groves, S.E.; Harwood, P.J.; Sanchez, R.J.

    1996-03-25

    The three-dimensional mechanical behavior of thick Spectra/epoxy sonar window materials containing various special materials is summarized in this report. Three different materials, which were fabricated by two companies known as `A` and `B` were received from the Naval Warfare Center. The three materials designated `A with microspheres (A micron),` `A without microspheres (A),` and `B` were measured for all properties. The total number of tests was reduced through the assumption that the two orthogonal, in-place directions were identical. Consequently, these materials should have only six independent elastic variables. The measured constants and strengths are given.

  8. Hyaluronic acid-coated liposomes for active targeting of gemcitabine.

    PubMed

    Arpicco, Silvia; Lerda, Carlotta; Dalla Pozza, Elisa; Costanzo, Chiara; Tsapis, Nicolas; Stella, Barbara; Donadelli, Massimo; Dando, Ilaria; Fattal, Elias; Cattel, Luigi; Palmieri, Marta

    2013-11-01

    The aim of this work was the preparation, characterization, and preliminary evaluation of the targeting ability toward pancreatic adenocarcinoma cells of liposomes containing the gemcitabine lipophilic prodrug [4-(N)-lauroyl-gemcitabine, C12GEM]. Hyaluronic acid (HA) was selected as targeting agent since it is biodegradable, biocompatible, and can be chemically modified and its cell surface receptor CD44 is overexpressed on various tumors. For this purpose, conjugates between a phospholipid, the 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), and HA of two different low molecular weights 4800 Da (12 disaccharidic units) and 12,000 Da (32 disaccharidic units), were prepared, characterized, and introduced in the liposomes during the preparation. Different liposomal formulations were prepared and their characteristics were analyzed: size, Z potential, and TEM analyses underline a difference in the HA-liposomes from the non-HA ones. In order to better understand the HA-liposome cellular localization and to evaluate their interaction with CD44 receptor, confocal microscopy studies were performed. The results demonstrate that HA facilitates the recognition of liposomes by MiaPaCa2 cells (CD44(+)) and that the uptake increases with increase in the polymer molecular weight. Finally, the cytotoxicity of the different preparations was evaluated and data show that incorporation of C12GEM increases their cytotoxic activity and that HA-liposomes inhibit cell growth more than plain liposomes. Altogether, the results demonstrate the specificity of C12GEM targeting toward CD44-overexpressing pancreatic adenocarcinoma cell line using HA as a ligand.

  9. Hyaluronic acid-coated liposomes for active targeting of gemcitabine.

    PubMed

    Arpicco, Silvia; Lerda, Carlotta; Dalla Pozza, Elisa; Costanzo, Chiara; Tsapis, Nicolas; Stella, Barbara; Donadelli, Massimo; Dando, Ilaria; Fattal, Elias; Cattel, Luigi; Palmieri, Marta

    2013-11-01

    The aim of this work was the preparation, characterization, and preliminary evaluation of the targeting ability toward pancreatic adenocarcinoma cells of liposomes containing the gemcitabine lipophilic prodrug [4-(N)-lauroyl-gemcitabine, C12GEM]. Hyaluronic acid (HA) was selected as targeting agent since it is biodegradable, biocompatible, and can be chemically modified and its cell surface receptor CD44 is overexpressed on various tumors. For this purpose, conjugates between a phospholipid, the 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), and HA of two different low molecular weights 4800 Da (12 disaccharidic units) and 12,000 Da (32 disaccharidic units), were prepared, characterized, and introduced in the liposomes during the preparation. Different liposomal formulations were prepared and their characteristics were analyzed: size, Z potential, and TEM analyses underline a difference in the HA-liposomes from the non-HA ones. In order to better understand the HA-liposome cellular localization and to evaluate their interaction with CD44 receptor, confocal microscopy studies were performed. The results demonstrate that HA facilitates the recognition of liposomes by MiaPaCa2 cells (CD44(+)) and that the uptake increases with increase in the polymer molecular weight. Finally, the cytotoxicity of the different preparations was evaluated and data show that incorporation of C12GEM increases their cytotoxic activity and that HA-liposomes inhibit cell growth more than plain liposomes. Altogether, the results demonstrate the specificity of C12GEM targeting toward CD44-overexpressing pancreatic adenocarcinoma cell line using HA as a ligand. PMID:23791684

  10. Active targeting schemes for nanoparticle systems in cancer therapeutics.

    PubMed

    Byrne, James D; Betancourt, Tania; Brannon-Peppas, Lisa

    2008-12-14

    The objective of this review is to outline current major cancer targets for nanoparticle systems and give insight into the direction of the field. The major targeting strategies that have been used for the delivery of therapeutic or imaging agents to cancer have been broken into three sections. These sections are angiogenesis-associated targeting, targeting to uncontrolled cell proliferation markers, and tumor cell targeting. The targeting schemes explored for many of the reported nanoparticle systems suggest the great potential of targeted delivery to revolutionize cancer treatment.

  11. Spawning behaviour of Allis shad Alosa alosa: new insights based on imaging sonar data.

    PubMed

    Langkau, M C; Clavé, D; Schmidt, M B; Borcherding, J

    2016-06-01

    Spawning behaviour of Alosa alosa was observed by high resolution imaging sonar. Detected clouds of sexual products and micro bubbles served as a potential indicator of spawning activity. Peak spawning time was between 0130 and 0200 hours at night. Increasing detections over three consecutive nights were consistent with sounds of mating events (bulls) assessed in hearing surveys in parallel to the hydro acoustic detection. In 70% of the analysed mating events there were no additional A. alosa joining the event whilst 70% of the mating events showed one or two A. alosa leaving the cloud. In 31% of the analysed mating events, however, three or more A. alosa were leaving the clouds, indicating that matings are not restricted to a pair. Imaging sonar is suitable for monitoring spawning activity and behaviour of anadromous clupeids in their spawning habitats. PMID:27126879

  12. Spawning behaviour of Allis shad Alosa alosa: new insights based on imaging sonar data.

    PubMed

    Langkau, M C; Clavé, D; Schmidt, M B; Borcherding, J

    2016-06-01

    Spawning behaviour of Alosa alosa was observed by high resolution imaging sonar. Detected clouds of sexual products and micro bubbles served as a potential indicator of spawning activity. Peak spawning time was between 0130 and 0200 hours at night. Increasing detections over three consecutive nights were consistent with sounds of mating events (bulls) assessed in hearing surveys in parallel to the hydro acoustic detection. In 70% of the analysed mating events there were no additional A. alosa joining the event whilst 70% of the mating events showed one or two A. alosa leaving the cloud. In 31% of the analysed mating events, however, three or more A. alosa were leaving the clouds, indicating that matings are not restricted to a pair. Imaging sonar is suitable for monitoring spawning activity and behaviour of anadromous clupeids in their spawning habitats.

  13. Epigenetic drugs that do not target enzyme activity.

    PubMed

    Owen, Dafydd R; Trzupek, John D

    2014-06-01

    While the installation and removal of epigenetic post-translational modifications or ‘marks’ on both DNA and histone proteins are the tangible outcome of enzymatically catalyzed processes, the role of the epigenetic reader proteins looks, at first, less obvious. As they do not catalyze a chemical transformation or process as such, their role is not enzymatic. However, this does not preclude them from being potential targets for drug discovery as their function is clearly correlated to transcriptional activity and as a class of proteins, they appear to have binding sites of sufficient definition and size to be inhibited by small molecules. This suggests that this third class of epigenetic proteins that are involved in the interpretation of post-translational marks (as opposed to the creation or deletion of marks) may represent attractive targets for drug discovery efforts. This review mainly summarizes selected publications, patent literature and company disclosures on these non-enzymatic epigenetic reader proteins from 2009 to the present.

  14. Rubisco activity and regulation as targets for crop improvement.

    PubMed

    Parry, Martin A J; Andralojc, P John; Scales, Joanna C; Salvucci, Michael E; Carmo-Silva, A Elizabete; Alonso, Hernan; Whitney, Spencer M

    2013-01-01

    Rubisco (ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase) enables net carbon fixation through the carboxylation of RuBP. However, some characteristics of Rubisco make it surprisingly inefficient and compromise photosynthetic productivity. For example, Rubisco catalyses a wasteful reaction with oxygen that leads to the release of previously fixed CO(2) and NH(3) and the consumption of energy during photorespiration. Furthermore, Rubisco is slow and large amounts are needed to support adequate photosynthetic rates. Consequently, Rubisco has been studied intensively as a prime target for manipulations to 'supercharge' photosynthesis and improve both productivity and resource use efficiency. The catalytic properties of Rubiscos from diverse sources vary considerably, suggesting that changes in turnover rate, affinity, or specificity for CO(2) can be introduced to improve Rubisco performance in specific crops and environments. While attempts to manipulate plant Rubisco by nuclear transformation have had limited success, modifying its catalysis by targeted changes to its catalytic large subunit via chloroplast transformation have been much more successful. However, this technique is still in need of development for most major food crops including maize, wheat, and rice. Other bioengineering approaches for improving Rubisco performance include improving the activity of its ancillary protein, Rubisco activase, in addition to modulating the synthesis and degradation of Rubisco's inhibitory sugar phosphate ligands. As the rate-limiting step in carbon assimilation, even modest improvements in the overall performance of Rubisco pose a viable pathway for obtaining significant gains in plant yield, particularly under stressful environmental conditions.

  15. Targeting silymarin for improved hepatoprotective activity through chitosan nanoparticles

    PubMed Central

    Gupta, Swati; Singh, Shailendra Kumar; Girotra, Priti

    2014-01-01

    Introduction: Silymarin is one of the best known hepatoprotective drugs, which is obtained from the seeds of Silybum marianum L., Family: Asteraceae or Compositae. The plant has traditionally been used for centuries as a natural remedy for liver and biliary tract diseases. The aim of the present investigation was to enhance the hepatoprotective activity of silymarin by incorporating it in chitosan (Ch) nanoparticles (NPs) for passive targeted delivery, thereby prolonging its retention time. Materials and Methods: Silymarin loaded NPs were prepared by ionic gelation technique, which were then optimized using a central composite design in order to minimize the particle size and maximize the drug entrapment efficiency. The optimized formulation was evaluated for in vitro drug release study and in vitro study on Swiss Albino mice using carbon tetrachloride (CCL4) induced hepatotoxicity model. Results: In vitro dissolution studies illustrated sustained, zero order drug release from optimized formulation; also its therapeutic potential was amplified during in vitro studies on Swiss Albino mice using CCL4 induced hepatotoxicity model. Conclusion: The results suggested that NPs of silymarin could successfully enhance its hepatoprotective effect by passive targeting and sustained release. PMID:25426436

  16. Thrombin-Mediated Direct Activation of Proteinase-Activated Receptor-2: Another Target for Thrombin Signaling.

    PubMed

    Mihara, Koichiro; Ramachandran, Rithwik; Saifeddine, Mahmoud; Hansen, Kristina K; Renaux, Bernard; Polley, Danny; Gibson, Stacy; Vanderboor, Christina; Hollenberg, Morley D

    2016-05-01

    Thrombin is known to signal to cells by cleaving/activating a G-protein-coupled family of proteinase-activated receptors (PARs). The signaling mechanism involves the proteolytic unmasking of an N-terminal receptor sequence that acts as a tethered receptor-activating ligand. To date, the recognized targets of thrombin cleavage and activation for signaling are PAR1 and PAR4, in which thrombin cleaves at a conserved target arginine to reveal a tethered ligand. PAR2, which like PAR1 is also cleaved at an N-terminal arginine to unmask its tethered ligand, is generally regarded as a target for trypsin but not for thrombin signaling. We now show that thrombin, at concentrations that can be achieved at sites of acute injury or in a tumor microenvironment, can directly activate PAR2 vasorelaxation and signaling, stimulating calcium and mitogen-activated protein kinase responses along with triggeringβ-arrestin recruitment. Thus, PAR2 can be added alongside PAR1 and PAR4 to the targets, whereby thrombin can affect tissue function.

  17. Activating frataxin expression by repeat-targeted nucleic acids.

    PubMed

    Li, Liande; Matsui, Masayuki; Corey, David R

    2016-02-04

    Friedreich's ataxia is an incurable genetic disorder caused by a mutant expansion of the trinucleotide GAA within an intronic FXN RNA. This expansion leads to reduced expression of frataxin (FXN) protein and evidence suggests that transcriptional repression is caused by an R-loop that forms between the expanded repeat RNA and complementary genomic DNA. Synthetic agents that increase levels of FXN protein might alleviate the disease. We demonstrate that introducing anti-GAA duplex RNAs or single-stranded locked nucleic acids into patient-derived cells increases FXN protein expression to levels similar to analogous wild-type cells. Our data are significant because synthetic nucleic acids that target GAA repeats can be lead compounds for restoring curative FXN levels. More broadly, our results demonstrate that interfering with R-loop formation can trigger gene activation and reveal a new strategy for upregulating gene expression.

  18. Audiomotor integration for active sensing in the echolocating bat, Eptesicus fuscus

    NASA Astrophysics Data System (ADS)

    Moss, Cynthia F.; Sinha, Shiva R.; Ghose, Kaushik

    2003-10-01

    Echolocating bats probe the environment with sonar signals that change as they seek, pursue and intercept insect prey on the wing. Coordinating its sonar vocalizations with flight dynamics in response to changing echo information, the bat exhibits a dazzling display of sensorimotor integration. Our work aims at understanding the mechanisms supporting audiomotor integration for echolocation in the FM-bat, Eptesicus fuscus. Behavioral studies measure adaptive responses of free-flying bats engaged in complex spatial tasks. The directional aim of the bat's sonar beam and temporal patterning of cries provide explicit data on the motor commands that feed directly back to the auditory system for spatially-guided behavior. Neural studies focus on the superior colliculus (SC), a midbrain structure implicated in species-specific orienting behaviors. A population of SC neurons shows echo-delay tuning, a response property believed to play a role in target range coding. Microstimulation of the SC elicits head and pinna movements, along with sonar vocalizations. SC recordings from tethered, vocalizing bats reveal bursts of neural activity preceding each sonar cry. Collectively, these results suggest that the bat SC plays a functional role in the auditory information processing and orienting behaviors that operate together in echolocation. [Work supported by NSF, NIMH and Whitehall Foundation.

  19. Enhanced detection with bimodal sonar displays.

    PubMed

    Doll, T J; Hanna, T E

    1989-10-01

    Signal-to-noise ratios (SNRs) required to detect narrow-band signals in white noise were compared for bimodal and single-modality sonar displays at two levels of signal uncertainty and two degrees of spatial compatibility between the auditory and visual displays. In bimodal test conditions the auditory and visual signals were equated in detectability for each subject. An adaptive, two-alternative, forced-choice procedure was used to maintain a constant percentage of correct responses. The decrement in performance with increased signal uncertainty was significantly greater for visual than for auditory displays, suggesting that auditory displays offer advantages for real-world sonar operations. Bimodal displays produced a reliable advantage in SNR required for detection over single-modality displays. Increased compatibility between the visual and auditory displays did not increase the advantage of bimodal presentation, nor did increased signal uncertainty. It was concluded that bimodal displays enhance operators' perceptual sensitivity. The magnitude of the enhancement was consistent with optimal integration of information in the two modalities.

  20. Higher Order Combination Tones Applied To Sonar Waveform Design And Underwater Digital Communications

    NASA Astrophysics Data System (ADS)

    Fogg, Stephen L.

    2006-05-01

    Nonlinear `parametric' sonar is distinguished by highly predictable in-water formations of identifiable von Helmholtz spectral energies produced directly as a result of two or more preselected primaries simultaneously contained in a transmit waveform. In the nearly half-century of scientific endeavors within the field of parametric sonar, the methodical investigation into formulation techniques and practical applications using higher-order combination tones has been noticeably lagging the attention received by their more commonly recognized kin of second-order sum and difference frequencies. Generalized mathematical and graphical viewing techniques are presented for elucidating the abundance of cross-band complexities and facilitating preliminary design efforts specifically employing any of these higher-order parametric frequency components on operational systems. Recent sonar experiments implementing pulsed parametric transmit waveforms intended to fully exploit their intrinsic broadband nonlinear energy have demonstrated the potential for improved underwater target detection and classification in acoustically harsh environments. However, research efforts could benefit from more efficient and universal tools for predetermining all of the desired in-water spectral-temporal characteristics. New developments utilizing this methodology have led to unique approaches for designing stepped CW, LFM and hyperbolic FM detection waveforms incorporating enhanced signal processing qualities and constructing coding schemes for reliable underwater acoustic digital communications.

  1. Sonar beam dynamics in leaf-nosed bats

    PubMed Central

    Linnenschmidt, Meike; Wiegrebe, Lutz

    2016-01-01

    Ultrasonic emissions of bats are directional and delimit the echo-acoustic space. Directionality is quantified by the aperture of the sonar beam. Recent work has shown that bats often widen their sonar beam when approaching movable prey or sharpen their sonar beam when navigating through cluttered habitats. Here we report how nose-emitting bats, Phyllostomus discolor, adjust their sonar beam to object distance. First, we show that the height and width of the bats sonar beam, as imprinted on a parabolic 45 channel microphone array, varies even within each animal and this variation is unrelated to changes in call level or spectral content. Second, we show that these animals are able to systematically decrease height and width of their sonar beam while focusing on the approaching object. Thus it appears that sonar beam sharpening is a further, facultative means of reducing search volume, likely to be employed by stationary animals when the object position is close and unambiguous. As only half of our individuals sharpened their beam onto the approaching object we suggest that this strategy is facultative, under voluntary control, and that beam formation is likely mediated by muscular control of the acoustic aperture of the bats’ nose leaf. PMID:27384865

  2. Sonar beam dynamics in leaf-nosed bats.

    PubMed

    Linnenschmidt, Meike; Wiegrebe, Lutz

    2016-01-01

    Ultrasonic emissions of bats are directional and delimit the echo-acoustic space. Directionality is quantified by the aperture of the sonar beam. Recent work has shown that bats often widen their sonar beam when approaching movable prey or sharpen their sonar beam when navigating through cluttered habitats. Here we report how nose-emitting bats, Phyllostomus discolor, adjust their sonar beam to object distance. First, we show that the height and width of the bats sonar beam, as imprinted on a parabolic 45 channel microphone array, varies even within each animal and this variation is unrelated to changes in call level or spectral content. Second, we show that these animals are able to systematically decrease height and width of their sonar beam while focusing on the approaching object. Thus it appears that sonar beam sharpening is a further, facultative means of reducing search volume, likely to be employed by stationary animals when the object position is close and unambiguous. As only half of our individuals sharpened their beam onto the approaching object we suggest that this strategy is facultative, under voluntary control, and that beam formation is likely mediated by muscular control of the acoustic aperture of the bats' nose leaf. PMID:27384865

  3. Sonar beam dynamics in leaf-nosed bats.

    PubMed

    Linnenschmidt, Meike; Wiegrebe, Lutz

    2016-01-01

    Ultrasonic emissions of bats are directional and delimit the echo-acoustic space. Directionality is quantified by the aperture of the sonar beam. Recent work has shown that bats often widen their sonar beam when approaching movable prey or sharpen their sonar beam when navigating through cluttered habitats. Here we report how nose-emitting bats, Phyllostomus discolor, adjust their sonar beam to object distance. First, we show that the height and width of the bats sonar beam, as imprinted on a parabolic 45 channel microphone array, varies even within each animal and this variation is unrelated to changes in call level or spectral content. Second, we show that these animals are able to systematically decrease height and width of their sonar beam while focusing on the approaching object. Thus it appears that sonar beam sharpening is a further, facultative means of reducing search volume, likely to be employed by stationary animals when the object position is close and unambiguous. As only half of our individuals sharpened their beam onto the approaching object we suggest that this strategy is facultative, under voluntary control, and that beam formation is likely mediated by muscular control of the acoustic aperture of the bats' nose leaf.

  4. 13 CFR 124.509 - What are non-8(a) business activity targets?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... activity targets? 124.509 Section 124.509 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION 8(a... Contractual Assistance § 124.509 What are non-8(a) business activity targets? (a) General. (1) To ensure that...) business activity targets during transitional stage—(1) General. During the transitional stage of the...

  5. 13 CFR 124.509 - What are non-8(a) business activity targets?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... activity targets? 124.509 Section 124.509 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION 8(a... Contractual Assistance § 124.509 What are non-8(a) business activity targets? (a) General. (1) To ensure that...) business activity targets during transitional stage—(1) General. During the transitional stage of the...

  6. 13 CFR 124.509 - What are non-8(a) business activity targets?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... activity targets? 124.509 Section 124.509 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION 8(a... Contractual Assistance § 124.509 What are non-8(a) business activity targets? (a) General. (1) To ensure that...) business activity targets during transitional stage—(1) General. During the transitional stage of the...

  7. The effect of preceding sonar emission on temporal integration in the bat, Megaderma lyra.

    PubMed

    Weissenbacher, Petra; Wiegrebe, Lutz; Kössl, Manfred

    2002-03-01

    The present study investigated whether and to which extent temporal integration in bats is influenced by echolocation behavior. One way to quantify temporal integration is to measure the detection threshold for a pair of short tone pips as a function of the temporal separation between the pips. To asses the effect of preceding sonar emission on temporal integration in the bat, Megaderma lyra, the detection thresholds of identical subjects were measured in a passive as well as in an active paradigm. In the passive paradigm, the presentation of the pip pairs was independent of the bats' sonar emissions; in the active paradigm, the presentation was triggered by the bats' sonar emissions. In both cases, the bats showed a very short integration time in the range of 100-200 micros. Moreover, the comparison of the active and passive results within each bat revealed no systematic differences in the two measuring paradigms. These results indicate that temporal integration is not influenced by echolocation. Simulations with a computer model of cochlear filtering based on measurements of M. lyra cochlear tuning suggest that the perceptual temporal integration is dominated by the integration of the cochlear filters.

  8. High-Resolution Multibeam Sonar Survey and Interactive 3-D Exploration of the D-Day Wrecks off Normandy

    NASA Astrophysics Data System (ADS)

    Mayer, L. A.; Calder, B.; Schmidt, J. S.

    2003-12-01

    Historically, archaeological investigations use sidescan sonar and marine magnetometers as initial search tools. Targets are then examined through direct observation by divers, video, or photographs. Magnetometers can demonstrate the presence, absence, and relative susceptibility of ferrous objects but provide little indication of the nature of the target. Sidescan sonar can present a clear image of the overall nature of a target and its surrounding environment, but the sidescan image is often distorted and contains little information about the true 3-D shape of the object. Optical techniques allow precise identification of objects but suffer from very limited range, even in the best of situations. Modern high-resolution multibeam sonar offers an opportunity to cover a relatively large area from a safe distance above the target, while resolving the true three-dimensional (3-D) shape of the object with centimeter-level resolution. The combination of 3-D mapping and interactive 3-D visualization techniques provides a powerful new means to explore underwater artifacts. A clear demonstration of the applicability of high-resolution multibeam sonar to wreck and artifact investigations occurred when the Naval Historical Center (NHC), the Center for Coastal and Ocean Mapping (CCOM) at the University of New Hampshire, and Reson Inc., collaborated to explore the state of preservation and impact on the surrounding environment of a series of wrecks located off the coast of Normandy, France, adjacent to the American landing sectors The survey augmented previously collected magnetometer and high-resolution sidescan sonar data using a Reson 8125 high-resolution focused multibeam sonar with 240, 0.5° (at nadir) beams distributed over a 120° swath. The team investigated 21 areas in water depths ranging from about three -to 30 meters (m); some areas contained individual targets such as landing craft, barges, a destroyer, troop carrier, etc., while others contained multiple smaller

  9. Echo detection and target-ranging neurons in the auditory system of the bat Eptesicus fuscus.

    PubMed

    Feng, A S; Simmons, J A; Kick, S A

    1978-11-10

    Some of the neurons in the nucleus intercollicularis and auditory cortex of the echolocating bat Eptesicus fuscus respond selectively to sonar echoes occurring with specific echo delays or pulse-echo intervals. They do not respond for a wide range of other types of sounds or for sonar echoes at longer or shorter pulse-echo intervals; they may, therefore, be specialized for detection and ranging of sonar targets.

  10. Active Targeted Nanoparticles for Oral Administration of Gastric Cancer Therapy.

    PubMed

    Lin, Yu-Hsin; Chen, Zih-Rou; Lai, Chih-Ho; Hsieh, Chia-Hung; Feng, Chun-Lung

    2015-09-14

    Gastric carcinogenesis is a commonly diagnosed type of cancer and has a dismal prognosis because of the rate at which it aggressively spreads and because of the lack of effective therapies to stop its progression. This study evaluated a type of oral drug delivery system of a potential target-activated nanosizer comprising a fucose-conjugated chitosan and polyethylene glycol-conjugated chitosan complex with gelatin containing encapsulated green tea polyphenol extract epigallocatechin-3-gallate, allowing oral administration of the drug through a site-specific release in gastric cancer cells. The results demonstrated that the nanoparticles effectively reduced drug release within gastric acids and that a controlled epigallocatechin-3-gallate release inhibited gastric cancer cell growth, induced cell apoptosis, and reduced vascular endothelial growth factor protein expression. Furthermore, in vivo assay results indicated that the prepared epigallocatechin-3-gallate-loaded fucose-chitosan/polyethylene glycol-chitosan/gelatin nanoparticles significantly affected gastric tumor activity and reduced gastric and liver tissue inflammatory reaction in an orthotopic gastric tumor mouse model.

  11. Genetic influences on composite neural activations supporting visual target identification.

    PubMed

    Ethridge, Lauren E; Malone, Stephen M; Iacono, William G; Clementz, Brett A

    2013-02-01

    Behavior genetic studies of brain activity associated with complex cognitive operations may further elucidate the genetic and physiological underpinnings of basic and complex neural processing. In the present project, monozygotic (N=51 pairs) and dizygotic (N=48 pairs) twins performed a visual oddball task with dense-array EEG. Using spatial PCA, two principal components each were retained for targets and standards; wavelets were used to obtain time-frequency maps of eigenvalue-weighted event-related oscillations for each individual. Distribution of inter-trial phase coherence (ITC) and single trial power (STP) over time indicated that the early principal component was primarily associated with ITC while the later component was associated with a mixture of ITC and STP. Spatial PCA on point-by-point broad sense heritability matrices revealed data-derived frequency bands similar to those well established in EEG literature. Biometric models of eigenvalue-weighted time-frequency data suggest a link between physiology of oscillatory brain activity and patterns of genetic influence. PMID:23201034

  12. Transforming growth factor-beta requires its target plasminogen activator inhibitor-1 for cytostatic activity.

    PubMed

    Kortlever, Roderik M; Nijwening, Jeroen H; Bernards, René

    2008-09-01

    The cytokine transforming growth factor beta (TGFbeta) has strong antiproliferative activity in most normal cells but contributes to tumor progression in the later stages of oncogenesis. It is not fully understood which TGFbeta target genes are causally involved in mediating its cytostatic activity. We report here that suppression of the TGFbeta target gene encoding plasminogen activator inhibitor-1 (PAI-1) by RNA interference leads to escape from the cytostatic activity of TGFbeta both in human keratinocytes (HaCaTs) and primary mouse embryo fibroblasts. Consistent with this, PAI-1 knock-out mouse embryo fibroblasts are also resistant to TGFbeta growth arrest. Conversely, we show that ectopic expression of PAI-1 in proliferating HaCaT cells induces a growth arrest. PAI-1 knockdown does not interfere with canonical TGFbeta signaling as judged by SMAD phosphorylation and induction of bona fide TGFbeta target genes. Instead, knockdown of PAI-1 results in sustained activation of protein kinase B. Significantly, we find that constitutive protein kinase B activity leads to evasion of the growth-inhibitory action of TGFbeta. Our data are consistent with a model in which induction of PAI-1 by TGFbeta is critical for the induction of proliferation arrest.

  13. Automatic gain control in the bat's sonar receiver and the neuroethology of echolocation.

    PubMed

    Kick, S A; Simmons, J A

    1984-11-01

    The sensitivity of the echolocating bat, Eptesicus fuscus, to sonar echoes at different time delays after sonar emissions was measured in a two-choice echo detection experiment. Since echo delay is perceptually equivalent to target range, the experiment effectively measured sensitivity to targets at different ranges. The bat's threshold for detecting sonar echoes at a short delay of only 1.0 msec after emissions (corresponding to a range of 17 cm) was 36 dB SPL (peak to peak), but the threshold decreased to 8 dB SPL at a longer delay of 6.4 msec (a range of 1.1 m). Prior research has shown that, at even longer delays (corresponding to ranges of 3 to 5 m), the bat's threshold is in the region of 0 dB SPL. Contractions of the bat's middle ear muscles synchronized with the production of echolocation sounds cause a transient loss in hearing sensitivity which appears to account for the observed echo detection threshold shifts. The bat's echo detection thresholds increase by approximately 11 dB for each reduction in target range by a factor of 2 over the span from 17 cm to 1.1 m. As range shortens, the amplitude of echoes from small targets also increases, by 12 dB for each 2-fold reduction in range. Thus, when approaching a target, the bat compensates for changes in echo strength as target range shortens by changing its hearing threshold. Since this compensation appears to occur in the middle ear, the bat regulates echoes reaching the cochlea to a stable amplitude during its approach to a target such as a flying insect. In addition to this automatic gain control linked to target range, the bat aims its head to track a target's position during approach, thus stabilizing echo amplitude even if the target's direction changes. We hypothesize that the bat's directional emissions, directional hearing, middle ear muscle contractions, and head aim response collectively create a three-dimensional spatial tracking filter which the bat locks onto targets to stabilize echo

  14. Optimal Predator Risk Assessment by the Sonar-Jamming Arctiine Moth Bertholdia trigona

    PubMed Central

    Corcoran, Aaron J.; Wagner, Ryan D.; Conner, William E.

    2013-01-01

    Nearly all animals face a tradeoff between seeking food and mates and avoiding predation. Optimal escape theory holds that an animal confronted with a predator should only flee when benefits of flight (increased survival) outweigh the costs (energetic costs, lost foraging time, etc.). We propose a model for prey risk assessment based on the predator's stage of attack. Risk level should increase rapidly from when the predator detects the prey to when it commits to the attack. We tested this hypothesis using a predator – the echolocating bat – whose active biosonar reveals its stage of attack. We used a prey defense – clicking used for sonar jamming by the tiger moth Bertholdia trigona– that can be readily studied in the field and laboratory and is enacted simultaneously with evasive flight. We predicted that prey employ defenses soon after being detected and targeted, and that prey defensive thresholds discriminate between legitimate predatory threats and false threats where a nearby prey is attacked. Laboratory and field experiments using playbacks of ultrasound signals and naturally behaving bats, respectively, confirmed our predictions. Moths clicked soon after bats detected and targeted them. Also, B. trigona clicking thresholds closely matched predicted optimal thresholds for discriminating legitimate and false predator threats for bats using search and approach phase echolocation – the period when bats are searching for and assessing prey. To our knowledge, this is the first quantitative study to correlate the sensory stimuli that trigger defensive behaviors with measurements of signals provided by predators during natural attacks in the field. We propose theoretical models for explaining prey risk assessment depending on the availability of cues that reveal a predator's stage of attack. PMID:23671686

  15. Optimal predator risk assessment by the sonar-jamming arctiine moth Bertholdia trigona.

    PubMed

    Corcoran, Aaron J; Wagner, Ryan D; Conner, William E

    2013-01-01

    Nearly all animals face a tradeoff between seeking food and mates and avoiding predation. Optimal escape theory holds that an animal confronted with a predator should only flee when benefits of flight (increased survival) outweigh the costs (energetic costs, lost foraging time, etc.). We propose a model for prey risk assessment based on the predator's stage of attack. Risk level should increase rapidly from when the predator detects the prey to when it commits to the attack. We tested this hypothesis using a predator--the echolocating bat--whose active biosonar reveals its stage of attack. We used a prey defense--clicking used for sonar jamming by the tiger moth Bertholdia trigona--that can be readily studied in the field and laboratory and is enacted simultaneously with evasive flight. We predicted that prey employ defenses soon after being detected and targeted, and that prey defensive thresholds discriminate between legitimate predatory threats and false threats where a nearby prey is attacked. Laboratory and field experiments using playbacks of ultrasound signals and naturally behaving bats, respectively, confirmed our predictions. Moths clicked soon after bats detected and targeted them. Also, B. trigona clicking thresholds closely matched predicted optimal thresholds for discriminating legitimate and false predator threats for bats using search and approach phase echolocation--the period when bats are searching for and assessing prey. To our knowledge, this is the first quantitative study to correlate the sensory stimuli that trigger defensive behaviors with measurements of signals provided by predators during natural attacks in the field. We propose theoretical models for explaining prey risk assessment depending on the availability of cues that reveal a predator's stage of attack.

  16. Quantifying Fish Backscattering using SONAR Instrument and Kirchhoff Ray Mode (KRM) Model

    NASA Astrophysics Data System (ADS)

    Manik, Henry M.

    2016-08-01

    Sonar instrument was used to study backscattering from tuna fish. Extraction of target strength, incidence angle, and frequency dependence of the backscattered signal for individual scatterer was important for biological information. For this purpose, acoustic measurement of fish backscatter was conducted in the laboratory. Characteristics and general trends of the target strength of fish with special reference to tuna fish were investigated by using a Kirchhoff Ray Mode (KRM) model. Backscattering strength were calculated for the KRM having typical morphological and physical parameters of actual fish. Those backscattering amplitudes were shown as frequency, body length, backscattering patterns, the density and sound speed dependences, and orientation dependence. These results were compared with experimentally measured target strength data and good agreement was found. Measurement and model showed the target strength from the fish are depend on the presence of swimbladder. Target Strength increase with increasing the frequency and fish length.

  17. Target of rapamycin activation predicts lifespan in fruit flies

    PubMed Central

    Scialò, Filippo; Sriram, Ashwin; Naudí, Alba; Ayala, Victoria; Jové, Mariona; Pamplona, Reinald; Sanz, Alberto

    2015-01-01

    Aging and age-related diseases are one of the most important health issues that the world will confront during the 21st century. Only by understanding the proximal causes will we be able to find treatments to reduce or delay the onset of degenerative diseases associated with aging. Currently, the prevalent paradigm in the field is the accumulation of damage. However, a new theory that proposes an alternative explanation is gaining momentum. The hyperfunction theory proposes that aging is not a consequence of a wear and tear process, but a result of the continuation of developmental programs during adulthood. Here we use Drosophila melanogaster, where evidence supporting both paradigms has been reported, to identify which parameters that have been previously related with lifespan best predict the rate of aging in wild type flies cultured at different temperatures. We find that mitochondrial function and mitochondrial reactive oxygen species (mtROS) generation correlates with metabolic rate, but not with the rate of aging. Importantly, we find that activation of nutrient sensing pathways (i.e. insulin-PI3K/Target of rapamycin (Tor) pathway) correlates with lifespan, but not with metabolic rate. Our results, dissociate metabolic rate and lifespan in wild type flies and instead link nutrient sensing signaling with longevity as predicted by the hyperfunction theory. PMID:26259964

  18. Automated change detection for synthetic aperture sonar

    NASA Astrophysics Data System (ADS)

    G-Michael, Tesfaye; Marchand, Bradley; Tucker, J. D.; Sternlicht, Daniel D.; Marston, Timothy M.; Azimi-Sadjadi, Mahmood R.

    2014-05-01

    In this paper, an automated change detection technique is presented that compares new and historical seafloor images created with sidescan synthetic aperture sonar (SAS) for changes occurring over time. The method consists of a four stage process: a coarse navigational alignment; fine-scale co-registration using the scale invariant feature transform (SIFT) algorithm to match features between overlapping images; sub-pixel co-registration to improves phase coherence; and finally, change detection utilizing canonical correlation analysis (CCA). The method was tested using data collected with a high-frequency SAS in a sandy shallow-water environment. By using precise co-registration tools and change detection algorithms, it is shown that the coherent nature of the SAS data can be exploited and utilized in this environment over time scales ranging from hours through several days.

  19. High-resolution adaptive spiking sonar.

    PubMed

    Alvarez, Fernando J; Kuc, Roman

    2009-05-01

    A new sonar system based on the conventional 6500 ranging module is presented that generates a sequence of spikes whose temporal density is related to the strength of the received echo. This system notably improves the resolution of a previous system by shortening the discharge cycle of the integrator included in the module. The operation is controlled by a PIC18F452 device, which can adapt the duration of the discharge to changing features of the echo, providing the system with a novel adaptive behavior. The performance of the new sensor is characterized and compared with that of the previous system by performing rotational scans of simple objects with different reflecting strengths. Some applications are suggested that exploit the high resolution and adaptability of this sensor.

  20. Application of mobile robot localization using sonar

    SciTech Connect

    Byrd, J.S.; Hill, K.H.

    1994-12-31

    A sonar-based mobile robot has been developed for inspection of low-level radioactive waste drums. An algorithm was developed which gives the robot the ability to refence itself to cylindrical objects. The drum-following algorithm has been demonstrated in 4-ft drum aisles at the Mobile Robotics Laboratory at the University of South Carolina. The final version has proven to be robust through extensive long-term navigation tests. Future enhancements will employ a narrow-aisle version of the Nav-master to allow navigation in 3-ft drum aisles. The final version of the inspection robot will include the drum-navigation algorithm as a low-level primitive instruction. The onboard management system will be dedicated to more of the high-level functions, such as planning, now provided by the offboard supervisory system.

  1. Multiresolution neural networks for mine detection in side scan sonar images

    NASA Astrophysics Data System (ADS)

    Guo, Weiming; Szymczak, William G.

    1998-09-01

    Statistical and neural network algorithms are used to separate mine targets from clutter in side scan sonar images. In these images, a typical target usually contains in excess of 100 pixels filled with salt and pepper noise. This translates into a problem of classifying in a complicated high dimensional space, which is very difficult if not impossible to solve. Therefore, a typical mine detection algorithm contains three stages preceding the classification algorithm: noise reduction, clutter rejection, and feature extraction. These pre-processing steps would reduce the dimension of the feature space by an order of magnitude. Side scan sonar images are known to be contaminated with noise and mine like clutter. The major challenge is to select and measure the features of the potential targets. This is frequently done by fractal and/or Fourier analysis. Recently, wavelet analysis has also been used successfully as a tool for feature extraction. However, there are few analytical rules to guide the selection of features. In this paper, we investigate a new integrated feature extraction and classification algorithm that first enhances a potential target using variational based algorithms, and then transforms the enhanced image into a set of wavelet channels. We use the multichannel information as inputs to a feed-forward neural network. This new classifier has the advantage of extracting not only the local features but also the background features through higher scale wavelet channels. Results are compared for different network designs.

  2. Beaked whales respond to simulated and actual navy sonar.

    PubMed

    Tyack, Peter L; Zimmer, Walter M X; Moretti, David; Southall, Brandon L; Claridge, Diane E; Durban, John W; Clark, Christopher W; D'Amico, Angela; DiMarzio, Nancy; Jarvis, Susan; McCarthy, Elena; Morrissey, Ronald; Ward, Jessica; Boyd, Ian L

    2011-03-14

    Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom-mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2-3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2-3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 µPa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define

  3. Beaked Whales Respond to Simulated and Actual Navy Sonar

    PubMed Central

    Tyack, Peter L.; Zimmer, Walter M. X.; Moretti, David; Southall, Brandon L.; Claridge, Diane E.; Durban, John W.; Clark, Christopher W.; D'Amico, Angela; DiMarzio, Nancy; Jarvis, Susan; McCarthy, Elena; Morrissey, Ronald; Ward, Jessica; Boyd, Ian L.

    2011-01-01

    Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom-mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2–3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2–3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 µPa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define

  4. Improved continuous wave frequency modulated sonars with aural displays.

    PubMed

    Boys, J T; Mason, J L; Hodgson, R M

    1978-05-01

    This paper discusses methods for reducing the effects of the reset hiatus and wavelength related variations in received signal strength on the aural displays produced by simple continuous wave frequency modulated sonars. Two techniques that have been developed for reducing the effects of signal phase and amplitude discontinuities are described. As a practical example of the improved performance afforded by one of these techniques, a novel short range sonar for examining cardiovascular structures is discussed in detail.

  5. A micro-Doppler sonar for acoustic surveillance in sensor networks

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaonian

    Wireless sensor networks have been employed in a wide variety of applications, despite the limited energy and communication resources at each sensor node. Low power custom VLSI chips implementing passive acoustic sensing algorithms have been successfully integrated into an acoustic surveillance unit and demonstrated for detection and location of sound sources. In this dissertation, I explore active and passive acoustic sensing techniques, signal processing and classification algorithms for detection and classification in a multinodal sensor network environment. I will present the design and characterization of a continuous-wave micro-Doppler sonar to image objects with articulated moving components. As an example application for this system, we use it to image gaits of humans and four-legged animals. I will present the micro-Doppler gait signatures of a walking person, a dog and a horse. I will discuss the resolution and range of this micro-Doppler sonar and use experimental results to support the theoretical analyses. In order to reduce the data rate and make the system amenable to wireless sensor networks, I will present a second micro-Doppler sonar that uses bandpass sampling for data acquisition. Speech recognition algorithms are explored for biometric identifications from one's gait, and I will present and compare the classification performance of the two systems. The acoustic micro-Doppler sonar design and biometric identification results are the first in the field as the previous work used either video camera or microwave technology. I will also review bearing estimation algorithms and present results of applying these algorithms for bearing estimation and tracking of moving vehicles. Another major source of the power consumption at each sensor node is the wireless interface. To address the need of low power communications in a wireless sensor network, I will also discuss the design and implementation of ultra wideband transmitters in a three dimensional

  6. Sources of uncertainty in Doppler sonar measurements of fish speed

    NASA Astrophysics Data System (ADS)

    Tollefsen, Cristina D. S.; Zedel, Len

    2001-05-01

    A 250-kHz, 30-kHz bandwidth coherent Doppler sonar was evaluated to determine sources of uncertainty in fish speed measurements. Three separate tests were undertaken: (1) towtank tests using styrofoam balls to simulate fish, (2) tank tests with live free-swimming fish, and (3) field tests with wild free-swimming fish. The standard deviation in a single speed estimate was 9 cms-1 for styrofoam balls, 10-11 cms-1 for swimming fish observed from a dorsal aspect, and 19 cms-1 for swimming fish observed from a caudal aspect. The variation in precision was primarily due to the different signal-to-noise ratio (SNR) in each test: a larger SNR resulted in a smaller standard deviation. Doppler speed estimates were compared with independent estimates of target speed where possible. An accuracy of +/-4 cms-1 was typical of Doppler speed estimates in all the experiments.

  7. Location and Characterization of Underwater Ordnance using Resonance Scattered Sonar

    NASA Astrophysics Data System (ADS)

    Gritto, R.; Korneev, V. A.

    2009-12-01

    Unexploded ordnance (UXO) present a worldwide hazard in locations of previous military confrontations and at military training facilities. In particular, the presence of unexploded ordinance in coastal regions poses a severe risk that must be addressed before sites can be turned over to the public or coastal areas made available for commercial traffic. Although progress has been made in detecting UXO in underwater areas, there still exists a need for technologies that can detect and locate UXO buried in seafloor sediments and reliably distinguish munitions from clutter. We are investigating a method based on resonance scattering using small data sets in a controlled pond environment. The use of resonance scattering allows for deeper bottom penetration than in the case of the generally used acoustic imaging, because in the former case the wavelengths are longer than the latter. Furthermore, in the resonance scattering regime the geometry is independent of the target orientation. The sonar data sets were acquired during 2006 and 2007 by the Applied Physics Laboratory, University of Washington, at the Surface Warfare Center, Panama City, FL, and included an aluminum cylinder and sphere, as well as artillery shells and mortar rounds buried in the sandy pond bottom. Our results show that resonance scattered waves, although smaller in amplitude than the specular reflected signal, dominate much of the recorded traces in time. These signals can be used to determine the propagation velocities in the pond sediments, to locate the UXO in the subsurface and to characterize the UXO type by its size and filler velocities.

  8. Neural network modeling of a dolphin's sonar discrimination capabilities.

    PubMed

    Au, W W; Andersen, L N; Rasmussen, A R; Roitblat, H L; Nachtigall, P E

    1995-07-01

    The capability of an echolocating dolphin to discriminate differences in the wall thickness of cylinders was previously modeled by a counterpropagation neural network using only spectral information from the echoes. In this study, both time and frequency information were used to model the dolphin discrimination capabilities. Echoes from the same cylinders were digitized using a broadband simulated dolphin sonar signal with the transducer mounted on the dolphin's pen. The echoes were filtered by a bank of continuous constant-Q digital filters and the energy from each filter was computed in time increments of 1/bandwidth. Echo features of the standard and each comparison target were analyzed in pairs by a counterpropagation neural network, a backpropagation neural network, and a model using Euclidean distance measures. The backpropagation network performed better than both the counterpropagation network, and the Euclidean model, using either spectral-only features or combined temporal and spectral features. All models performed better using features containing both temporal and spectral information. The backpropagation network was able to perform better than the dolphins for noise-free echoes with Q values as low as 2 and 3. For a Q of 2, only temporal information was available. However, with noisy data, the network required a Q of 8 in order to perform as well as the dolphin.

  9. Graphical derivations of radar, sonar, and communication signals

    NASA Technical Reports Server (NTRS)

    Altes, R. A.; Titlebaum, E. L.

    1975-01-01

    The designer of a communication system often has knowledge concerning the changes in distance between transmitter and receiver as a function of time. This information can be exploited to reduce multipath interference via proper signal design. A radar or sonar may also have good a priori information about possible target trajectories. Such knowledge can again be used to reduce the receiver's response to clutter (MTI), to enhance signal-to-noise ratio, or to simplify receiver design. There are also situations in which prior knowledge about trajectories is lacking. The system should then utilize a single-filter pair which is insensitive to the effects induced by relative motion between transmitter, receiver, and reflectors. For waveforms with large time-bandwidth products, such as long pulse trains, it is possible to graphically derive signal formats for both situations (trajectory known and unknown). Although the exact form of the signal is sometimes not specified by the graphical procedure, the problem in such cases is reduced to one which has already been solved, i.e., the generation of an impulse equivalent code.

  10. Multimodal integration of micro-Doppler sonar and auditory signals for behavior classification with convolutional networks.

    PubMed

    Dura-Bernal, Salvador; Garreau, Guillaume; Georgiou, Julius; Andreou, Andreas G; Denham, Susan L; Wennekers, Thomas

    2013-10-01

    The ability to recognize the behavior of individuals is of great interest in the general field of safety (e.g. building security, crowd control, transport analysis, independent living for the elderly). Here we report a new real-time acoustic system for human action and behavior recognition that integrates passive audio and active micro-Doppler sonar signatures over multiple time scales. The system architecture is based on a six-layer convolutional neural network, trained and evaluated using a dataset of 10 subjects performing seven different behaviors. Probabilistic combination of system output through time for each modality separately yields 94% (passive audio) and 91% (micro-Doppler sonar) correct behavior classification; probabilistic multimodal integration increases classification performance to 98%. This study supports the efficacy of micro-Doppler sonar systems in characterizing human actions, which can then be efficiently classified using ConvNets. It also demonstrates that the integration of multiple sources of acoustic information can significantly improve the system's performance.

  11. Multimodal integration of micro-Doppler sonar and auditory signals for behavior classification with convolutional networks.

    PubMed

    Dura-Bernal, Salvador; Garreau, Guillaume; Georgiou, Julius; Andreou, Andreas G; Denham, Susan L; Wennekers, Thomas

    2013-10-01

    The ability to recognize the behavior of individuals is of great interest in the general field of safety (e.g. building security, crowd control, transport analysis, independent living for the elderly). Here we report a new real-time acoustic system for human action and behavior recognition that integrates passive audio and active micro-Doppler sonar signatures over multiple time scales. The system architecture is based on a six-layer convolutional neural network, trained and evaluated using a dataset of 10 subjects performing seven different behaviors. Probabilistic combination of system output through time for each modality separately yields 94% (passive audio) and 91% (micro-Doppler sonar) correct behavior classification; probabilistic multimodal integration increases classification performance to 98%. This study supports the efficacy of micro-Doppler sonar systems in characterizing human actions, which can then be efficiently classified using ConvNets. It also demonstrates that the integration of multiple sources of acoustic information can significantly improve the system's performance. PMID:23924412

  12. BatSLAM: Simultaneous Localization and Mapping Using Biomimetic Sonar

    PubMed Central

    Steckel, Jan; Peremans, Herbert

    2013-01-01

    We propose to combine a biomimetic navigation model which solves a simultaneous localization and mapping task with a biomimetic sonar mounted on a mobile robot to address two related questions. First, can robotic sonar sensing lead to intelligent interactions with complex environments? Second, can we model sonar based spatial orientation and the construction of spatial maps by bats? To address these questions we adapt the mapping module of RatSLAM, a previously published navigation system based on computational models of the rodent hippocampus. We analyze the performance of the proposed robotic implementation operating in the real world. We conclude that the biomimetic navigation model operating on the information from the biomimetic sonar allows an autonomous agent to map unmodified (office) environments efficiently and consistently. Furthermore, these results also show that successful navigation does not require the readings of the biomimetic sonar to be interpreted in terms of individual objects/landmarks in the environment. We argue that the system has applications in robotics as well as in the field of biology as a simple, first order, model for sonar based spatial orientation and map building. PMID:23365647

  13. BatSLAM: Simultaneous localization and mapping using biomimetic sonar.

    PubMed

    Steckel, Jan; Peremans, Herbert

    2013-01-01

    We propose to combine a biomimetic navigation model which solves a simultaneous localization and mapping task with a biomimetic sonar mounted on a mobile robot to address two related questions. First, can robotic sonar sensing lead to intelligent interactions with complex environments? Second, can we model sonar based spatial orientation and the construction of spatial maps by bats? To address these questions we adapt the mapping module of RatSLAM, a previously published navigation system based on computational models of the rodent hippocampus. We analyze the performance of the proposed robotic implementation operating in the real world. We conclude that the biomimetic navigation model operating on the information from the biomimetic sonar allows an autonomous agent to map unmodified (office) environments efficiently and consistently. Furthermore, these results also show that successful navigation does not require the readings of the biomimetic sonar to be interpreted in terms of individual objects/landmarks in the environment. We argue that the system has applications in robotics as well as in the field of biology as a simple, first order, model for sonar based spatial orientation and map building. PMID:23365647

  14. Sonar image segmentation using an unsupervised hierarchical MRF model.

    PubMed

    Mignotte, M; Collet, C; Perez, P; Bouthemy, P

    2000-01-01

    This paper is concerned with hierarchical Markov random field (MRP) models and their application to sonar image segmentation. We present an original hierarchical segmentation procedure devoted to images given by a high-resolution sonar. The sonar image is segmented into two kinds of regions: shadow (corresponding to a lack of acoustic reverberation behind each object lying on the sea-bed) and sea-bottom reverberation. The proposed unsupervised scheme takes into account the variety of the laws in the distribution mixture of a sonar image, and it estimates both the parameters of noise distributions and the parameters of the Markovian prior. For the estimation step, we use an iterative technique which combines a maximum likelihood approach (for noise model parameters) with a least-squares method (for MRF-based prior). In order to model more precisely the local and global characteristics of image content at different scales, we introduce a hierarchical model involving a pyramidal label field. It combines coarse-to-fine causal interactions with a spatial neighborhood structure. This new method of segmentation, called the scale causal multigrid (SCM) algorithm, has been successfully applied to real sonar images and seems to be well suited to the segmentation of very noisy images. The experiments reported in this paper demonstrate that the discussed method performs better than other hierarchical schemes for sonar image segmentation.

  15. BatSLAM: Simultaneous localization and mapping using biomimetic sonar.

    PubMed

    Steckel, Jan; Peremans, Herbert

    2013-01-01

    We propose to combine a biomimetic navigation model which solves a simultaneous localization and mapping task with a biomimetic sonar mounted on a mobile robot to address two related questions. First, can robotic sonar sensing lead to intelligent interactions with complex environments? Second, can we model sonar based spatial orientation and the construction of spatial maps by bats? To address these questions we adapt the mapping module of RatSLAM, a previously published navigation system based on computational models of the rodent hippocampus. We analyze the performance of the proposed robotic implementation operating in the real world. We conclude that the biomimetic navigation model operating on the information from the biomimetic sonar allows an autonomous agent to map unmodified (office) environments efficiently and consistently. Furthermore, these results also show that successful navigation does not require the readings of the biomimetic sonar to be interpreted in terms of individual objects/landmarks in the environment. We argue that the system has applications in robotics as well as in the field of biology as a simple, first order, model for sonar based spatial orientation and map building.

  16. Enhanced echolocation via robust statistics and super-resolution of sonar images

    NASA Astrophysics Data System (ADS)

    Kim, Kio

    Echolocation is a process in which an animal uses acoustic signals to exchange information with environments. In a recent study, Neretti et al. have shown that the use of robust statistics can significantly improve the resiliency of echolocation against noise and enhance its accuracy by suppressing the development of sidelobes in the processing of an echo signal. In this research, the use of robust statistics is extended to problems in underwater explorations. The dissertation consists of two parts. Part I describes how robust statistics can enhance the identification of target objects, which in this case are cylindrical containers filled with four different liquids. Particularly, this work employs a variation of an existing robust estimator called an L-estimator, which was first suggested by Koenker and Bassett. As pointed out by Au et al.; a 'highlight interval' is an important feature, and it is closely related with many other important features that are known to be crucial for dolphin echolocation. A varied L-estimator described in this text is used to enhance the detection of highlight intervals, which eventually leads to a successful classification of echo signals. Part II extends the problem into 2 dimensions. Thanks to the advances in material and computer technology, various sonar imaging modalities are available on the market. By registering acoustic images from such video sequences, one can extract more information on the region of interest. Computer vision and image processing allowed application of robust statistics to the acoustic images produced by forward looking sonar systems, such as Dual-frequency Identification Sonar and ProViewer. The first use of robust statistics for sonar image enhancement in this text is in image registration. Random Sampling Consensus (RANSAC) is widely used for image registration. The registration algorithm using RANSAC is optimized for sonar image registration, and the performance is studied. The second use of robust

  17. 78 FR 35612 - Agency Information Collection Activities; Comment Request; Targeted Teacher Shortage Areas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-13

    ... collection of information from Chief State School Officers to support and document the request for teacher... Agency Information Collection Activities; Comment Request; Targeted Teacher Shortage Areas Nationwide... to this notice will be considered public records. Title of Collection: Targeted Teacher...

  18. Bypassing Protein Corona Issue on Active Targeting: Zwitterionic Coatings Dictate Specific Interactions of Targeting Moieties and Cell Receptors.

    PubMed

    Safavi-Sohi, Reihaneh; Maghari, Shokoofeh; Raoufi, Mohammad; Jalali, Seyed Amir; Hajipour, Mohammad J; Ghassempour, Alireza; Mahmoudi, Morteza

    2016-09-01

    Surface functionalization strategies for targeting nanoparticles (NP) to specific organs, cells, or organelles, is the foundation for new applications of nanomedicine to drug delivery and biomedical imaging. Interaction of NPs with biological media leads to the formation of a biomolecular layer at the surface of NPs so-called as "protein corona". This corona layer can shield active molecules at the surface of NPs and cause mistargeting or unintended scavenging by the liver, kidney, or spleen. To overcome this corona issue, we have designed biotin-cysteine conjugated silica NPs (biotin was employed as a targeting molecule and cysteine was used as a zwitterionic ligand) to inhibit corona-induced mistargeting and thus significantly enhance the active targeting capability of NPs in complex biological media. To probe the targeting yield of our engineered NPs, we employed both modified silicon wafer substrates with streptavidin (i.e., biotin receptor) to simulate a target and a cell-based model platform using tumor cell lines that overexpress biotin receptors. In both cases, after incubation with human plasma (thus forming a protein corona), cellular uptake/substrate attachment of the targeted NPs with zwitterionic coatings were significantly higher than the same NPs without zwitterionic coating. Our results demonstrated that NPs with a zwitterionic surface can considerably facilitate targeting yield of NPs and provide a promising new type of nanocarriers in biological applications.

  19. Bypassing Protein Corona Issue on Active Targeting: Zwitterionic Coatings Dictate Specific Interactions of Targeting Moieties and Cell Receptors.

    PubMed

    Safavi-Sohi, Reihaneh; Maghari, Shokoofeh; Raoufi, Mohammad; Jalali, Seyed Amir; Hajipour, Mohammad J; Ghassempour, Alireza; Mahmoudi, Morteza

    2016-09-01

    Surface functionalization strategies for targeting nanoparticles (NP) to specific organs, cells, or organelles, is the foundation for new applications of nanomedicine to drug delivery and biomedical imaging. Interaction of NPs with biological media leads to the formation of a biomolecular layer at the surface of NPs so-called as "protein corona". This corona layer can shield active molecules at the surface of NPs and cause mistargeting or unintended scavenging by the liver, kidney, or spleen. To overcome this corona issue, we have designed biotin-cysteine conjugated silica NPs (biotin was employed as a targeting molecule and cysteine was used as a zwitterionic ligand) to inhibit corona-induced mistargeting and thus significantly enhance the active targeting capability of NPs in complex biological media. To probe the targeting yield of our engineered NPs, we employed both modified silicon wafer substrates with streptavidin (i.e., biotin receptor) to simulate a target and a cell-based model platform using tumor cell lines that overexpress biotin receptors. In both cases, after incubation with human plasma (thus forming a protein corona), cellular uptake/substrate attachment of the targeted NPs with zwitterionic coatings were significantly higher than the same NPs without zwitterionic coating. Our results demonstrated that NPs with a zwitterionic surface can considerably facilitate targeting yield of NPs and provide a promising new type of nanocarriers in biological applications. PMID:27526263

  20. Utilizing the folate receptor for active targeting of cancer nanotherapeutics

    PubMed Central

    Zwicke, Grant L.; Mansoori, G. Ali; Jeffery, Constance J.

    2012-01-01

    The development of specialized nanoparticles for use in the detection and treatment of cancer is increasing. Methods are being proposed and tested that could target treatments more directly to cancer cells, which could lead to higher efficacy and reduced toxicity, possibly even eliminating the adverse effects of damage to the immune system and the loss of quick replicating cells. In this mini-review we focus on recent studies that employ folate nanoconjugates to target the folate receptor. Folate receptors are highly overexpressed on the surface of many tumor types. This expression can be exploited to target imaging molecules and therapeutic compounds directly to cancerous tissues. PMID:23240070

  1. Target Assembly to Check Boresight Alignment of Active Sensors

    NASA Technical Reports Server (NTRS)

    Ramos-Izquierdo, Luis; Scott, V. Stanley; Riris, Haris; Cavanaugh, John; Liiva, Peter; Rodriguez, Michael

    2011-01-01

    A compact and portable target assembly (Fig. 1) has been developed to measure the boresite alignment of LRO's Lunar Orbiter Laser Altimeter (LOLA) instrument at the spacecraft level. The concept for this target assembly has evolved over many years with earlier versions used to test the Mars Observer Laser Altimeter (MOLA), the Geoscience Laser Altimeter System (GLAS), and the Mercury Laser Altimeter (MLA) space-based instruments.

  2. Adaptive-filter/feature-orthogonalization processing string for optimal LLRT mine classfication in side-scan sonar imagery

    NASA Astrophysics Data System (ADS)

    Aridgides, Tom; Libera, Peter; Fernandez, Manuel F.; Dobeck, Gerald J.

    1996-05-01

    An automatic, robust, adaptive clutter suppression, mine detection and classification processing string has been developed and applied to side-scan sonar imagery data. The overall processing string includes data pre-processing, adaptive clutter filtering (ACF), 2D normalization, detection, feature extraction, and classification processing blocks. The data pre-processing block contains automatic gain control and data decimation processing. The ACF technique designs a 2D adaptive range-crossrange linear FIR filter which is optimal in the Least Squares sense, simultaneously suppressing the background clutter while preserving an average peak target signature (normalized shape) computed a priori using training set data. A multiple reference ACF algorithm version was utilized to account for multiple target shapes (due to different mine types, multiple target aspect angles, etc.). The detection block consists of thresholding, clustering of exceedances and limiting their number, and a secondary thresholding process. Following feature extraction, the classification block applies a novel transformation to the data, which orthogonalizes the features and enables an efficient application of the optimal log-likelihood-ratio-test (LLRT) classification rule. The utility of the overall processing string was demonstrated with two side-scan sonar data sets. The ACF/feature orthogonalization based LLRT mine classification processing string provided average probability of correct mine classification and false alarm rate performance similar to that obtained when utilizing an expert sonar operator.

  3. Bio-inspired wideband sonar signals based on observations of the bottlenose dolphin (Tursiops truncatus).

    PubMed

    Capus, Chris; Pailhas, Yan; Brown, Keith; Lane, David M; Moore, Patrick W; Houser, Dorian

    2007-01-01

    This paper uses advanced time-frequency signal analysis techniques to generate new models for bio-inspired sonar signals. The inspiration comes from the analysis of bottlenose dolphin clicks. These pulses are very short duration, between 50 and 80 micros, but for certain examples we can delineate a double down-chirp structure using fractional Fourier methods. The majority of clicks have energy distributed between two main frequency bands with the higher frequencies delayed in time by 5-20 micros. Signal syntheses using a multiple chirp model based on these observations are able to reproduce much of the spectral variation seen in earlier studies on natural dolphin echolocation pulses. Six synthetic signals are generated and used to drive the dolphin based sonar (DBS) developed through the Biosonar Program office at the SPAWAR Systems Center, San Diego, CA. Analyses of the detailed echo structure for these pulses ensonifying two solid copper spherical targets indicate differences in discriminatory potential between the signals. It is suggested that target discrimination could be improved through the transmission of a signal packet in which the chirp structure is varied between pulses. Evidence that dolphins may use such a strategy themselves comes from observations of variations in the transmissions of dolphins carrying out target detection and identification tasks.

  4. Ionizing Radiation Activates AMP-Activated Kinase (AMPK): A Target for Radiosensitization of Human Cancer Cells

    SciTech Connect

    Sanli, Toran; Rashid, Ayesha; Liu Caiqiong

    2010-09-01

    Purpose: Adenosine monophosphate (AMP)-activated kinase (AMPK) is a molecular energy sensor regulated by the tumor suppressor LKB1. Starvation and growth factors activate AMPK through the DNA damage sensor ataxia-telangiectasia mutated (ATM). We explored the regulation of AMPK by ionizing radiation (IR) and its role as a target for radiosensitization of human cancer cells. Methods and Materials: Lung, prostate, and breast cancer cells were treated with IR (2-8 Gy) after incubation with either ATM or AMPK inhibitors or the AMPK activator metformin. Then, cells were subjected to either lysis and immunoblotting, immunofluorescence microscopy, clonogenic survival assays, or cell cycle analysis. Results: IR induced a robust phosphorylation and activation of AMPK in all tumor cells, independent of LKB1. IR activated AMPK first in the nucleus, and this extended later into cytoplasm. The ATM inhibitor KU-55933 blocked IR activation of AMPK. AMPK inhibition with Compound C or anti-AMPK {alpha} subunit small interfering RNA (siRNA) blocked IR induction of the cell cycle regulators p53 and p21{sup waf/cip} as well as the IR-induced G2/M arrest. Compound C caused resistance to IR, increasing the surviving fraction after 2 Gy, but the anti-diabetic drug metformin enhanced IR activation of AMPK and lowered the surviving fraction after 2 Gy further. Conclusions: We provide evidence that IR activates AMPK in human cancer cells in an LKB1-independent manner, leading to induction of p21{sup waf/cip} and regulation of the cell cycle and survival. AMPK appears to (1) participate in an ATM-AMPK-p21{sup waf/cip} pathway, (2) be involved in regulation of the IR-induced G2/M checkpoint, and (3) may be targeted by metformin to enhance IR responses.

  5. "Gas and fat embolic syndrome" involving a mass stranding of beaked whales (family Ziphiidae) exposed to anthropogenic sonar signals.

    PubMed

    Fernández, A; Edwards, J F; Rodríguez, F; Espinosa de los Monteros, A; Herráez, P; Castro, P; Jaber, J R; Martín, V; Arbelo, M

    2005-07-01

    A study of the lesions of beaked whales (BWs) in a recent mass stranding in the Canary Islands following naval exercises provides a possible explanation of the relationship between anthropogenic, acoustic (sonar) activities and the stranding and death of marine mammals. Fourteen BWs were stranded in the Canary Islands close to the site of an international naval exercise (Neo-Tapon 2002) held on 24 September 2002. Strandings began about 4 hours after the onset of midfrequency sonar activity. Eight Cuvier's BWs (Ziphius cavirostris), one Blainville's BW (Mesoplodon densirostris), and one Gervais' BW (Mesoplodon europaeus) were examined postmortem and studied histopathologically. No inflammatory or neoplastic processes were noted, and no pathogens were identified. Macroscopically, whales had severe, diffuse congestion and hemorrhage, especially around the acoustic jaw fat, ears, brain, and kidneys. Gas bubble-associated lesions and fat embolism were observed in the vessels and parenchyma of vital organs. In vivo bubble formation associated with sonar exposure that may have been exacerbated by modified diving behavior caused nitrogen supersaturation above a threshold value normally tolerated by the tissues (as occurs in decompression sickness). Alternatively, the effect that sonar has on tissues that have been supersaturated with nitrogen gas could be such that it lowers the threshold for the expansion of in vivo bubble precursors (gas nuclei). Exclusively or in combination, these mechanisms may enhance and maintain bubble growth or initiate embolism. Severely injured whales died or became stranded and died due to cardiovascular collapse during beaching. The present study demonstrates a new pathologic entity in cetaceans. The syndrome is apparently induced by exposure to mid-frequency sonar signals and particularly affects deep, long-duration, repetitive-diving species like BWs.

  6. Recent ATR and fusion algorithm improvements for multiband sonar imagery

    NASA Astrophysics Data System (ADS)

    Aridgides, Tom; Fernández, Manuel

    2009-05-01

    An improved automatic target recognition processing string has been developed. The overall processing string consists of pre-processing, subimage adaptive clutter filtering, normalization, detection, data regularization, feature extraction, optimal subset feature selection, feature orthogonalization and classification processing blocks. The objects that are classified by the 3 distinct ATR strings are fused using the classification confidence values and their expansions as features, and using "summing" or log-likelihood-ratio-test (LLRT) based fusion rules. The utility of the overall processing strings and their fusion was demonstrated with new high-resolution three-frequency band sonar imagery. The ATR processing strings were individually tuned to the corresponding three-frequency band data, making use of the new processing improvement, data regularization; this improvement entails computing the input data mean, clipping the data to a multiple of its mean and scaling it, prior to feature extraction and resulted in a 3:1 reduction in false alarms. Two significant fusion algorithm improvements were made. First, a nonlinear exponential Box-Cox expansion (consisting of raising data to a to-be-determined power) feature LLRT fusion algorithm was developed. Second, a repeated application of a subset Box-Cox feature selection / feature orthogonalization / LLRT fusion block was utilized. It was shown that cascaded Box-Cox feature LLRT fusion of the ATR processing strings outperforms baseline "summing" and single-stage Box-Cox feature LLRT algorithms, yielding significant improvements over the best single ATR processing string results, and providing the capability to correctly call the majority of targets while maintaining a very low false alarm rate.

  7. Implementation and testing of a Deep Water Correlation Velocity Sonar

    SciTech Connect

    Dickey, F.R.; Bookheimer, W.C.; Rhoades, K.W.

    1983-05-01

    The paper describes a new sonar designated the Magnavox MX 810 Deep Water Correlation Sonar which is under development by the General Electric Company and the Magnavox Advanced Products and Systems Company. The sonar measures ship's velocity relative to the bottom but instead of using the conventional doppler effect, it uses the correlation method described by Dickey and Edward in 1978. In this method, the narrow beams required for doppler are not needed and a low frequency that penetrates to the bottom in deep water is used. The sonar was designed with the constraint that it use a transducer that mounts through a single 12 inch gate valve. Most offshore geophysical surveys at present make use of an integrated navigation system with bottom referenced velocity input from a doppler sonar which, because of limitations on the sonar bottomtracking range, has difficulty in areas where the water depth is greater than about 500 meters. The MX 810 provides bottom tracking in regions of much greater water depth. It also may be applied as an aid in continuous positioning of a vessel over a fixed location. It also should prove useful as a more general navigation aid. The sonar is undergoing a series of tests using Magnavox's facilities for the purpose of verifying the performance and obtaining data to support and quantify planned improvements in both software and hardware. A prototype transducer of only 5 watts power output was used, but in spite of this low power, successful operation to depths of 1900 meters was obtained. Extrapolation to system parameters to be implemented in production models predicts operation to depths of 5000 meters.

  8. Action Enhances Acoustic Cues for 3-D Target Localization by Echolocating Bats

    PubMed Central

    Wohlgemuth, Melville J.

    2016-01-01

    Under natural conditions, animals encounter a barrage of sensory information from which they must select and interpret biologically relevant signals. Active sensing can facilitate this process by engaging motor systems in the sampling of sensory information. The echolocating bat serves as an excellent model to investigate the coupling between action and sensing because it adaptively controls both the acoustic signals used to probe the environment and movements to receive echoes at the auditory periphery. We report here that the echolocating bat controls the features of its sonar vocalizations in tandem with the positioning of the outer ears to maximize acoustic cues for target detection and localization. The bat’s adaptive control of sonar vocalizations and ear positioning occurs on a millisecond timescale to capture spatial information from arriving echoes, as well as on a longer timescale to track target movement. Our results demonstrate that purposeful control over sonar sound production and reception can serve to improve acoustic cues for localization tasks. This finding also highlights the general importance of movement to sensory processing across animal species. Finally, our discoveries point to important parallels between spatial perception by echolocation and vision. PMID:27608186

  9. Action Enhances Acoustic Cues for 3-D Target Localization by Echolocating Bats.

    PubMed

    Wohlgemuth, Melville J; Kothari, Ninad B; Moss, Cynthia F

    2016-09-01

    Under natural conditions, animals encounter a barrage of sensory information from which they must select and interpret biologically relevant signals. Active sensing can facilitate this process by engaging motor systems in the sampling of sensory information. The echolocating bat serves as an excellent model to investigate the coupling between action and sensing because it adaptively controls both the acoustic signals used to probe the environment and movements to receive echoes at the auditory periphery. We report here that the echolocating bat controls the features of its sonar vocalizations in tandem with the positioning of the outer ears to maximize acoustic cues for target detection and localization. The bat's adaptive control of sonar vocalizations and ear positioning occurs on a millisecond timescale to capture spatial information from arriving echoes, as well as on a longer timescale to track target movement. Our results demonstrate that purposeful control over sonar sound production and reception can serve to improve acoustic cues for localization tasks. This finding also highlights the general importance of movement to sensory processing across animal species. Finally, our discoveries point to important parallels between spatial perception by echolocation and vision.

  10. Action Enhances Acoustic Cues for 3-D Target Localization by Echolocating Bats.

    PubMed

    Wohlgemuth, Melville J; Kothari, Ninad B; Moss, Cynthia F

    2016-09-01

    Under natural conditions, animals encounter a barrage of sensory information from which they must select and interpret biologically relevant signals. Active sensing can facilitate this process by engaging motor systems in the sampling of sensory information. The echolocating bat serves as an excellent model to investigate the coupling between action and sensing because it adaptively controls both the acoustic signals used to probe the environment and movements to receive echoes at the auditory periphery. We report here that the echolocating bat controls the features of its sonar vocalizations in tandem with the positioning of the outer ears to maximize acoustic cues for target detection and localization. The bat's adaptive control of sonar vocalizations and ear positioning occurs on a millisecond timescale to capture spatial information from arriving echoes, as well as on a longer timescale to track target movement. Our results demonstrate that purposeful control over sonar sound production and reception can serve to improve acoustic cues for localization tasks. This finding also highlights the general importance of movement to sensory processing across animal species. Finally, our discoveries point to important parallels between spatial perception by echolocation and vision. PMID:27608186

  11. GSK621 Targets Glioma Cells via Activating AMP-Activated Protein Kinase Signalings

    PubMed Central

    Jiang, Hong; Liu, Wei; Zhan, Shi-Kun; Pan, Yi-Xin; Bian, Liu-Guan; Sun, Bomin; Sun, Qing-Fang; Pan, Si-Jian

    2016-01-01

    Here, we studied the anti-glioma cell activity by a novel AMP-activated protein kinase (AMPK) activator GSK621. We showed that GSK621 was cytotoxic to human glioma cells (U87MG and U251MG lines), possibly via provoking caspase-dependent apoptotic cell death. Its cytotoxicity was alleviated by caspase inhibitors. GSK621 activated AMPK to inhibit mammalian target of rapamycin (mTOR) and downregulate Tetraspanin 8 (Tspan8) in glioma cells. AMPK inhibition, through shRNA knockdown of AMPKα or introduction of a dominant negative (T172A) AMPKα, almost reversed GSK621-induced AMPK activation, mTOR inhibition and Tspan8 degradation. Consequently, GSK621’s cytotoxicity in glioma cells was also significantly attenuated by AMPKα knockdown or mutation. Further studies showed that GSK621, at a relatively low concentration, significantly potentiated temozolomide (TMZ)’s sensitivity and lethality against glioma cells. We summarized that GSK621 inhibits human glioma cells possibly via activating AMPK signaling. This novel AMPK activator could be a novel and promising anti-glioma cell agent. PMID:27532105

  12. 27 CFR 478.35 - Skeet, trap, target, and similar shooting activities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2013-04-01 2013-04-01 false Skeet, trap, target, and... FIREARMS AND AMMUNITION Administrative and Miscellaneous Provisions § 478.35 Skeet, trap, target, and... records, for skeet, trap, target, and similar organized activities shall be determined by the Director...

  13. 27 CFR 478.35 - Skeet, trap, target, and similar shooting activities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Skeet, trap, target, and... FIREARMS AND AMMUNITION Administrative and Miscellaneous Provisions § 478.35 Skeet, trap, target, and... records, for skeet, trap, target, and similar organized activities shall be determined by the Director...

  14. 27 CFR 478.35 - Skeet, trap, target, and similar shooting activities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2012-04-01 2010-04-01 true Skeet, trap, target, and... FIREARMS AND AMMUNITION Administrative and Miscellaneous Provisions § 478.35 Skeet, trap, target, and... records, for skeet, trap, target, and similar organized activities shall be determined by the Director...

  15. 27 CFR 478.35 - Skeet, trap, target, and similar shooting activities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2014-04-01 2014-04-01 false Skeet, trap, target, and... FIREARMS AND AMMUNITION Administrative and Miscellaneous Provisions § 478.35 Skeet, trap, target, and... records, for skeet, trap, target, and similar organized activities shall be determined by the Director...

  16. 27 CFR 478.35 - Skeet, trap, target, and similar shooting activities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2011-04-01 2010-04-01 true Skeet, trap, target, and... FIREARMS AND AMMUNITION Administrative and Miscellaneous Provisions § 478.35 Skeet, trap, target, and... records, for skeet, trap, target, and similar organized activities shall be determined by the Director...

  17. 13 CFR 124.509 - What are non-8(a) business activity targets?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... competitive marketplace after graduating from the 8(a) BD program, Participants must make maximum efforts to... reasonable marketing strategy, to attain the targeted dollar levels of non-8(a) revenue established in its... source or competitive 8(a) contracts). These targets are called non-8(a) business activity targets...

  18. Immuno-magnetoliposomes targeting activated platelets as a potentially human-compatible MRI contrast agent for targeting atherothrombosis.

    PubMed

    Meier, S; Pütz, G; Massing, U; Hagemeyer, C E; von Elverfeldt, D; Meissner, M; Ardipradja, K; Barnert, S; Peter, K; Bode, C; Schubert, R; von zur Muhlen, C

    2015-06-01

    To detect unstable atherosclerotic plaques early and noninvasively would be of great clinical interest. Activated platelets are an interesting molecular target for detecting early lesions or unstable plaques. We therefore developed an MRI contrast agent consisting of magnetoliposomes (ML) linked to an antibody (anti-LIBS) specifically targeting the ligand-induced binding site of the activated GPIIb/IIIa receptor of platelets. ML were prepared by dual centrifugation (DC). ML pegylation up to a total PEG content of 7.5 mol% positively influenced the stability and amount of entrapped SPIOs, and also reduced SPIO-membrane interactions, while higher PEG contents destabilized PEG-ML. Stable anti-LIBS-ML with high amounts of entrapped SPIOs (∼86%, ∼0.22 mol Fe/mol liposomal lipid) and high MRI sensitivity (relaxivity r2 = 422 s(-1) mM(-1) and r2(∗) = 452 s(-1) mM(-1)) were obtained by coupling anti-LIBS to ML in a two-step post-insertion technique. We confirmed specific binding to the GPIIb/IIIa receptor's activated conformation on activated human platelets and cell lines expressing activated GPIIb/IIIa receptor ex vivo. The immuno-ML obtained in this study constitute an important step towards developing a potentially human-compatible MRI contrast agent for the timely detection of plaque rupture by targeting activated platelets.

  19. Modeling interface roughness scattering in a layered seabed for normal-incident chirp sonar signals.

    PubMed

    Tang, Dajun; Hefner, Brian T

    2012-04-01

    Downward looking sonar, such as the chirp sonar, is widely used as a sediment survey tool in shallow water environments. Inversion of geo-acoustic parameters from such sonar data precedes the availability of forward models. An exact numerical model is developed to initiate the simulation of the acoustic field produced by such a sonar in the presence of multiple rough interfaces. The sediment layers are assumed to be fluid layers with non-intercepting rough interfaces.

  20. The diagnosis of early pregnancy failure by sonar.

    PubMed

    Robinson, H P

    1975-11-01

    In a series of 425 consecutive patients examined by sonar in the first half of pregnancy 176 ultimately aborted. On analysis of the sonar and post-abortion findings it was found that the aborted pregnancies fell into five clearly defined groups; blighted ova or anembryonic pregnancies, missed abortions, hydatidiform moles and early and late live abortions. The blighted ova and the missed abortions comprised by far the largest and the early live abortions the smallest groups. Strict diagnostic sonar criteria of abnormality, independent of menstrual or clinical histories, were established for the first three of the groups, and an absolute diagnosis could be made at the time of the first examination in all cases of missed abortion and hydatidiform mole and in just over half of the cases of blighted ovum, the remainder requiring a second and occasionally a third examination. In the first half of the study the majority of the patients were allowed to abort spontaneously but with increasing confidence in the techniques patients were offered termination whenever the diagnosis of an abortive pregnancy was made. Anticipation of fetal death in utero or impending abortion of a live fetus proved to be a much more difficult problem, and in only those patients who aborted a live fetus before the tenth week of pregnancy did the sonar examination reveal any significant abnormality. Possible aetiological backgrounds to these groups of abortions are discussed in the light of the sonar findings.

  1. Sonar-induced temporary hearing loss in dolphins.

    PubMed

    Mooney, T Aran; Nachtigall, Paul E; Vlachos, Stephanie

    2009-08-23

    There is increasing concern that human-produced ocean noise is adversely affecting marine mammals, as several recent cetacean mass strandings may have been caused by animals' interactions with naval 'mid-frequency' sonar. However, it has yet to be empirically demonstrated how sonar could induce these strandings or cause physiological effects. In controlled experimental studies, we show that mid-frequency sonar can induce temporary hearing loss in a bottlenose dolphin (Tursiops truncatus). Mild-behavioural alterations were also associated with the exposures. The auditory effects were induced only by repeated exposures to intense sonar pings with total sound exposure levels of 214 dB re: 1 microPa(2) s. Data support an increasing energy model to predict temporary noise-induced hearing loss and indicate that odontocete noise exposure effects bear trends similar to terrestrial mammals. Thus, sonar can induce physiological and behavioural effects in at least one species of odontocete; however, exposures must be of prolonged, high sound exposures levels to generate these effects.

  2. Fast nearfield to farfield conversion algorithm for circular synthetic aperture sonar.

    PubMed

    Plotnick, Daniel S; Marston, Philip L; Marston, Timothy M

    2014-08-01

    Monostatic circular synthetic aperture sonar (CSAS) images are formed by processing azimuthal angle dependent backscattering from a target at a fixed distance from a collocated source/receiver. Typical CSAS imaging algorithms [Ferguson and Wyber, J. Acoust. Soc. Am. 117, 2915-2928 (2005)] assume scattering data are taken in the farfield. Experimental constraints may make farfield measurements impractical and thus require objects to be scanned in the nearfield. Left uncorrected this results in distortions of the target image and in the angular dependence of features. A fast approximate Hankel function based algorithm is presented to convert nearfield data to the farfield. Images and spectrograms of an extended target are compared for both cases.

  3. Selective Activation of Neuronal Targets With Sinusoidal Electric Stimulation

    PubMed Central

    Freeman, Daniel K.; Eddington, Donald K.; Rizzo, Joseph F.

    2010-01-01

    Electric stimulation of the CNS is being evaluated as a treatment modality for a variety of neurological, psychiatric, and sensory disorders. Despite considerable success in some applications, existing stimulation techniques offer little control over which cell types or neuronal substructures are activated by stimulation. The ability to more precisely control neuronal activation would likely improve the clinical outcomes associated with these applications. Here, we show that specific frequencies of sinusoidal stimulation can be used to preferentially activate certain retinal cell types: photoreceptors are activated at 5 Hz, bipolar cells at 25 Hz, and ganglion cells at 100 Hz. In addition, low-frequency stimulation (≤25 Hz) did not activate passing axons but still elicited robust synaptically mediated responses in ganglion cells; therefore, elicited neural activity is confined to within a focal region around the stimulating electrode. Our results suggest that sinusoidal stimulation provides significantly improved control over elicited neural activity relative to conventional pulsatile stimulation. PMID:20810683

  4. Echolocation with bat buzz emissions: model and biomimetic sonar for elevation estimation.

    PubMed

    Kuc, Roman

    2012-01-01

    Just prior to capture the Buzz II emissions of some mouth-emitting bats, such as Eptesicus fuscus, are observed to exhibit spectra having multiple peaks. This paper proposes an echolocation strategy that uses such spectra with energy concentrated in specific frequency bands for determining target elevation. A biomimetic sonar was implemented to produce a tri-modal spectrum by driving a speaker with a signal rich in harmonics. The emission magnitudes at these harmonic frequencies measured as a function of elevation in the zero-azimuth plane form distinct beams. A template was formed from the ratio of the first harmonic and fundamental magnitudes to determine elevation. The elevation estimator exhibited a sub-degree accuracy (SD = 0.4° over a 20° interval centered at the elevation at which these two beams intersect in the zero-azimuth plane. Spectral cues from -40° to +10° elevation allow a qualitative non-linear control of sonar orientation to drive the target to the beam-intersection point where quantitative elevation estimates are available.

  5. Aptamers: Active Targeting Ligands for Cancer Diagnosis and Therapy

    PubMed Central

    Wu, Xu; Chen, Jiao; Wu, Min; Zhao, Julia Xiaojun

    2015-01-01

    Aptamers, including DNA, RNA and peptide aptamers, are a group of promising recognition units that can specifically bind to target molecules and cells. Due to their excellent specificity and high affinity to targets, aptamers have attracted great attention in various fields in which selective recognition units are required. They have been used in biosensing, drug delivery, disease diagnosis and therapy (especially for cancer treatment). In this review, we summarized recent applications of DNA and RNA aptamers in cancer theranostics. The specific binding ability of aptamers to cancer-related markers and cancer cells ensured their high performance for early diagnosis of cancer. Meanwhile, the efficient targeting ability of aptamers to cancer cells and tissues provided a promising way to deliver imaging agents and drugs for cancer imaging and therapy. Furthermore, with the development of nanoscience and nanotechnology, the conjugation of aptamers with functional nanomaterials paved an exciting way for the fabrication of theranostic agents for different types of cancers, which might be a powerful tool for cancer treatment. PMID:25699094

  6. 78 FR 68091 - Certain Marine Sonar Imaging Devices, Products Containing the Same, and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-13

    ... COMMISSION Certain Marine Sonar Imaging Devices, Products Containing the Same, and Components Thereof... importation, and the sale within the United States after importation of certain marine sonar imaging devices... sale within the United States after importation of certain marine sonar imaging devices,...

  7. Compound Structure-Independent Activity Prediction in High-Dimensional Target Space.

    PubMed

    Balfer, Jenny; Hu, Ye; Bajorath, Jürgen

    2014-08-01

    Profiling of compound libraries against arrays of targets has become an important approach in pharmaceutical research. The prediction of multi-target compound activities also represents an attractive task for machine learning with potential for drug discovery applications. Herein, we have explored activity prediction in high-dimensional target space. Different types of models were derived to predict multi-target activities. The models included naïve Bayesian (NB) and support vector machine (SVM) classifiers based upon compound structure information and NB models derived on the basis of activity profiles, without considering compound structure. Because the latter approach can be applied to incomplete training data and principally depends on the feature independence assumption, SVM modeling was not applicable in this case. Furthermore, iterative hybrid NB models making use of both activity profiles and compound structure information were built. In high-dimensional target space, NB models utilizing activity profile data were found to yield more accurate activity predictions than structure-based NB and SVM models or hybrid models. An in-depth analysis of activity profile-based models revealed the presence of correlation effects across different targets and rationalized prediction accuracy. Taken together, the results indicate that activity profile information can be effectively used to predict the activity of test compounds against novel targets.

  8. Quantification of Diffuse Hydrothermal Flows Using Multibeam Sonar

    NASA Astrophysics Data System (ADS)

    Ivakin, A. N.; Jackson, D. R.; Bemis, K. G.; Xu, G.

    2014-12-01

    The Cabled Observatory Vent Imaging Sonar (COVIS) deployed at the Main Endeavour node of the NEPTUNE Canada observatory has provided acoustic time series extending over 2 years. This includes 3D images of plume scattering strength and Doppler velocity measurements as well as 2D images showing regions of diffuse flow. The diffuse-flow images display the level of decorrelation between sonar echos with transmissions separated by 0.2 s. The present work aims to provide further information on the strength of diffuse flows. Two approaches are used: Measurement of the dependence of decorrelation on lag and measurement of phase shift of sonar echos, with lags in 3-hour increments up to several days. The phase shifts and decorrelation are linked to variations of temperature above the seabed, which allows quantification of those variations, their magnitudes, spatial and temporal scales, and energy spectra. These techniques are illustrated using COVIS data obtained near the Grotto vent complex.

  9. Sonar surveys used in gas-storage cavern analysis

    SciTech Connect

    Crossley, N.G.

    1998-05-04

    Natural-gas storage cavern internal configuration, inspection information, and cavern integrity data can be obtained during high-pressure operations with specialized gas-sonar survey logging techniques. TransGas Ltd., Regina, Sask., has successfully performed these operations on several of its deepest and highest pressurized caverns. The data can determine gas-in-place inventory and assess changes in spatial volumes. These changes can result from cavern creep, shrinkage, or closure or from various downhole abnormalities such as fluid infill or collapse of the sidewall or roof. The paper discusses conventional surveys with sonar, running surveys in pressurized caverns, accuracy of the sonar survey, initial development of Cavern 5, a roof fall, Cavern 4 development, and a damaged string.

  10. Sperm whales reduce foraging effort during exposure to 1-2 kHz sonar and killer whale sounds.

    PubMed

    Isojunno, Saana; Cure, Charlotte; Kvadsheim, Petter Helgevold; Lam, Frans-Peter Alexander; Tyack, Peter Lloyd; Wensveen, Paul Jacobus; Miller, Patrick James O'Malley

    2016-01-01

    The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non-foraging, non-resting state during both experimental transmissions of low-frequency active sonar from an approaching vessel (LFAS; 1-2 kHz, source level 214 dB re 1 µPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records). Time spent in foraging states and the probability of prey capture attempts were reduced during these two types of exposures with little change in overall locomotion activity, suggesting an effect on energy intake with no immediate compensation. Whales switched to the active non-foraging state over received sound pressure levels of 131-165 dB re 1 µPa during LFAS exposure. In contrast, no changes in foraging behavior were detected in response to experimental negative controls (no-sonar ship approach or noise control playback) or to experimental medium-frequency active sonar exposures (MFAS; 6-7 kHz, source level 199 re 1 µPa m, received sound pressure level [SPL] = 73-158 dB re 1 µPa). Similarly, there was no reduction in foraging effort for three whales exposed to incidental, unidentified 4.7-5.1 kHz sonar signals received at lower levels (SPL = 89-133 dB re 1 µPa). These results demonstrate that similar to predation risk, exposure to sonar can affect functional behaviors, and indicate that increased perception of risk with higher source level or lower frequency may modulate how sperm whales respond to anthropogenic sound. PMID:27039511

  11. Sperm whales reduce foraging effort during exposure to 1-2 kHz sonar and killer whale sounds.

    PubMed

    Isojunno, Saana; Cure, Charlotte; Kvadsheim, Petter Helgevold; Lam, Frans-Peter Alexander; Tyack, Peter Lloyd; Wensveen, Paul Jacobus; Miller, Patrick James O'Malley

    2016-01-01

    The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non-foraging, non-resting state during both experimental transmissions of low-frequency active sonar from an approaching vessel (LFAS; 1-2 kHz, source level 214 dB re 1 µPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records). Time spent in foraging states and the probability of prey capture attempts were reduced during these two types of exposures with little change in overall locomotion activity, suggesting an effect on energy intake with no immediate compensation. Whales switched to the active non-foraging state over received sound pressure levels of 131-165 dB re 1 µPa during LFAS exposure. In contrast, no changes in foraging behavior were detected in response to experimental negative controls (no-sonar ship approach or noise control playback) or to experimental medium-frequency active sonar exposures (MFAS; 6-7 kHz, source level 199 re 1 µPa m, received sound pressure level [SPL] = 73-158 dB re 1 µPa). Similarly, there was no reduction in foraging effort for three whales exposed to incidental, unidentified 4.7-5.1 kHz sonar signals received at lower levels (SPL = 89-133 dB re 1 µPa). These results demonstrate that similar to predation risk, exposure to sonar can affect functional behaviors, and indicate that increased perception of risk with higher source level or lower frequency may modulate how sperm whales respond to anthropogenic sound.

  12. High-resolution imaging of the Okinawa Trough deep-tow sonar WADATSUMI exploration

    NASA Astrophysics Data System (ADS)

    Okino, K.; Tokuyama, H.; Takeuchi, A.; Sibuet, J. C.; Lee, C. S.

    2003-04-01

    High-resolution deep-tow side scan sonar data collected in the Okinawa Trough reveal details of the volcanic and tectonic features occurring along an active backarc rift zone, including an active hydrothermal vent site. Our new system, the deep-tow vector sidescan sonar WADATSUMI, is a 100 kHz system, which provides not only high-resolution backscattering images but also phase bathymetry. The system also includes a 3-6 kHz chirp sonar to investigate sub-bottom structure. The swath width for this survey is 1 km for a towing altitude of 100 to 350 m. The pixel size of the collected images is 50 cm. The towfish positioning is based on the ISBL (inverted short baseline) system, in which the signal transmitted from the ship is received at the towfish and all information is sent to the onboard control unit using co-axial cable. Four MAPRs (Miniature Autonomous Plume Recorder / provided by NOAA) were also equipped on the deep-tow system to detect hydrothermal activity using its thermometer and nephelometer. The Okinawa Trough, located between Japan and Taiwan, is an incipient backarc basin formed by extension within continental lithosphere behind the Ryukyu trench-arc system. The continuous formation of new oceanic crust has not yet occurred, however, crustal thinning and rifting is ongoing and many normal faults have developed. The southwestern part of the trough is most active and contains many interesting features, such as numerous volcanoes crossing the rift zone, high heat flow, and active hydrothermal site. The WADATSUMI images revealed the detailed volcanic and tectonic structure of the axial rift and a hydrothermal site. In the western area seafloor is dominated by volcanic construction, including hummocks, sheet flows, and blocky lava terrains. Small volcanic cones with crater pits are aligned along an E-W direction, which may constitute an elongated volcanic ridge within the graben. On the other hand, the eastern part of the survey area is a sedimented, deep

  13. Abnormal Ventral and Dorsal Attention Network Activity during Single and Dual Target Detection in Schizophrenia

    PubMed Central

    Jimenez, Amy M.; Lee, Junghee; Wynn, Jonathan K.; Cohen, Mark S.; Engel, Stephen A.; Glahn, David C.; Nuechterlein, Keith H.; Reavis, Eric A.; Green, Michael F.

    2016-01-01

    Early visual perception and attention are impaired in schizophrenia, and these deficits can be observed on target detection tasks. These tasks activate distinct ventral and dorsal brain networks which support stimulus-driven and goal-directed attention, respectively. We used single and dual target rapid serial visual presentation (RSVP) tasks during fMRI with an ROI approach to examine regions within these networks associated with target detection and the attentional blink (AB) in 21 schizophrenia outpatients and 25 healthy controls. In both tasks, letters were targets and numbers were distractors. For the dual target task, the second target (T2) was presented at three different lags after the first target (T1) (lag1 = 100 ms, lag3 = 300 ms, lag7 = 700ms). For both single and dual target tasks, patients identified fewer targets than controls. For the dual target task, both groups showed the expected AB effect with poorer performance at lag 3 than at lags 1 or 7, and there was no group by lag interaction. During the single target task, patients showed abnormally increased deactivation of the temporo-parietal junction (TPJ), a key region of the ventral network. When attention demands were increased during the dual target task, patients showed overactivation of the posterior intraparietal cortex, a key dorsal network region, along with failure to deactivate TPJ. Results suggest inefficient and faulty suppression of salience-oriented processing regions, resulting in increased sensitivity to stimuli in general, and difficulty distinguishing targets from non-targets. PMID:27014135

  14. Hydrothermal fountains imaged by high resolution side-scan sonar equipped on a cruising AUV, URASHIMA

    NASA Astrophysics Data System (ADS)

    Kumagai, H.; Tsukioka, S.; Yamamoto, H.; Shitashima, K.; Yamamoto, F.; Sawa, T.; Hyakudome, T.; Kasaya, T.; Kinoshita, M.

    2007-12-01

    Mapping of an area and intensities of activity at a particular hydrothermal field has required huge effort so far, typically several tens of dives of manned submersibles and/or ROVs to obtain detailed locality map with needed resolutions. Thus, appropriate remote sensing techniques have been desired since the discovery of seafloor hydrothermal field. A series of successful trials has been performed by ABE of WHOI equipped with a Eh-sensor (Yoerger et al., Oceanography, 2007). A 100kHz side-scan sonar (SSS) equipped on a cruising AUV, URASHIMA, caught detailed structural image of hydrothermal fountains rooting active chimneys during YK07-07 Cruise off Okinawa Isl. (May 6-18, 2007). The URASHIMA AUV is a 10-m-length cylindrical-shaped one that originally optimized to long distance cruise. In the expedition, she cruised near the sea floor with 50-100 m altitude, at the area of 1000-1500 m in WD. She has currently basic oceanographic/CTD sensors, a 400kHz echo-sounder and sonars of 100400 kHz side-scan sonar and up to 6 kHz sub-bottom profiler. In this operation, pH and ORP sensors (CRIEPI) were also attached in front of AUV. On the pre-processing image of SSS, numbers of filament-shape echoes were recorded within water column zone. The reason why they should be the echo from hydrothermal plumes are as folows; 1) the echoes in the water column were limitedly recorded above the active hydrothermal field; 2) CTD and pH sensors show temperature and pH anomaly corresponding to the record of echoes; 3) some of the root of the filament-shape echoes correspond to the hydrothermal mound recognized in the detailed bathymetry obtained with SeaBat7125 MNBES. This-like technique should revolute the mapping work prior to the sampling at the particular hydrothermal site.

  15. The sonar equation and the definitions of propagation loss.

    PubMed

    Ainslie, Michael A

    2004-01-01

    A rigorous application of the traditional definition of sonar equation terms leads to the appearance of an unexpected factor, not routinely included, equal to the ratio of the characteristic impedance at the receiver to that at the source. An omission of this factor can lead to non-negligible errors for realistic conditions. It is further argued that a gradual change in the de facto definition of propagation loss occurred between 1965 and 1980. Two alternatives to the traditional sonar equation are suggested, each using one of the two propagation loss definitions and both eliminating the unwanted impedance ratio.

  16. Antifungal activity of redox-active benzaldehydes that target cellular antioxidation

    PubMed Central

    2011-01-01

    Background Disruption of cellular antioxidation systems should be an effective method for control of fungal pathogens. Such disruption can be achieved with redox-active compounds. Natural phenolic compounds can serve as potent redox cyclers that inhibit microbial growth through destabilization of cellular redox homeostasis and/or antioxidation systems. The aim of this study was to identify benzaldehydes that disrupt the fungal antioxidation system. These compounds could then function as chemosensitizing agents in concert with conventional drugs or fungicides to improve antifungal efficacy. Methods Benzaldehydes were tested as natural antifungal agents against strains of Aspergillus fumigatus, A. flavus, A. terreus and Penicillium expansum, fungi that are causative agents of human invasive aspergillosis and/or are mycotoxigenic. The yeast Saccharomyces cerevisiae was also used as a model system for identifying gene targets of benzaldehydes. The efficacy of screened compounds as effective chemosensitizers or as antifungal agents in formulations was tested with methods outlined by the Clinical Laboratory Standards Institute (CLSI). Results Several benzaldehydes are identified having potent antifungal activity. Structure-activity analysis reveals that antifungal activity increases by the presence of an ortho-hydroxyl group in the aromatic ring. Use of deletion mutants in the oxidative stress-response pathway of S. cerevisiae (sod1Δ, sod2Δ, glr1Δ) and two mitogen-activated protein kinase (MAPK) mutants of A. fumigatus (sakAΔ, mpkCΔ), indicates antifungal activity of the benzaldehydes is through disruption of cellular antioxidation. Certain benzaldehydes, in combination with phenylpyrroles, overcome tolerance of A. fumigatus MAPK mutants to this agent and/or increase sensitivity of fungal pathogens to mitochondrial respiration inhibitory agents. Synergistic chemosensitization greatly lowers minimum inhibitory (MIC) or fungicidal (MFC) concentrations. Effective

  17. Sonar gain control and echo detection thresholds in the echolocating bat, Eptesicus fuscus.

    PubMed

    Simmons, J A; Moffat, A J; Masters, W M

    1992-02-01

    The echolocating bat, Eptesicus fuscus, detects sonar echoes with a sensitivity that changes according to the time elapsed between broadcasting of each sonar signal and reception of echoes. When tested in an electronic target simulator on a two-choice echo-detection task, the bat's threshold improved by 11.5 dB as echo delay changed from 2.3 to 4.6 ms (target ranges of 40 and 80 cm). Earlier experiments measured the change in detection threshold for delays from 1 to 6.4 ms (target ranges from about 17 to 110 cm) and obtained about 11 dB of improvement per doubling of delay. The new experiments used electronic delay lines to simulate echo delay, thus avoiding movement of loudspeakers to different distances and the possible creation of delay-dependent backward masking between stimulus echoes and cluttering echoes from the loudspeaker surfaces. The slope of the threshold shift defines an echo gain control that keeps echoes from point targets at a fixed sensation level--reducing sensitivity by 11 to 12 dB as echo amplitude increases by 12 dB per halving of range during the bat's approach to the target. A recent experiment using loudness discrimination of echoes at 70 to 80 dB SPL (roughly 50 dB above threshold) found a slope of about 6 dB per halving of range, so the gain-control effect may be level dependent. The observed effect is operationally equivalent to forward masking of echoes by the transmission, but any events correlated with vocalization which impair hearing sensitivity for a short interval following transmissions could cause a decline in sensitivity to echoes. Contractions of the bat's middle-ear muscles synchronized to transmissions may account for the observed threshold shift, at least for a span of echo delays associated with the most critical portion of the approach stage of pursuit. Forward masking by the sonar transmissions may contribute to the threshold shift, too, but middle-ear muscle contractions do occur and must be a significant part of the

  18. Nanobody conjugated PLGA nanoparticles for active targeting of African Trypanosomiasis.

    PubMed

    Arias, José L; Unciti-Broceta, Juan D; Maceira, José; Del Castillo, Teresa; Hernández-Quero, José; Magez, Stefan; Soriano, Miguel; García-Salcedo, José A

    2015-01-10

    Targeted delivery of therapeutics is an alternative approach for the selective treatment of infectious diseases. The surface of African trypanosomes, the causative agents of African trypanosomiasis, is covered by a surface coat consisting of a single variant surface glycoprotein, termed VSG. This coat is recycled by endocytosis at a very high speed, making the trypanosome surface an excellent target for the delivery of trypanocidal drugs. Here, we report the design of a drug nanocarrier based on poly ethylen glycol (PEG) covalently attached (PEGylated) to poly(D,L-lactide-co-glycolide acid) (PLGA) to generate PEGylated PLGA nanoparticles. This nanocarrier was coupled to a single domain heavy chain antibody fragment (nanobody) that specifically recognizes the surface of the protozoan pathogen Trypanosoma brucei. Nanoparticles were loaded with pentamidine, the first-line drug for T. b. gambiense acute infection. An in vitro effectiveness assay showed a 7-fold decrease in the half-inhibitory concentration (IC50) of the formulation relative to free drug. Furthermore, in vivo therapy using a murine model of African trypanosomiasis demonstrated that the formulation cured all infected mice at a 10-fold lower dose than the minimal full curative dose of free pentamidine and 60% of mice at a 100-fold lower dose. This nanocarrier has been designed with components approved for use in humans and loaded with a drug that is currently in use to treat the disease. Moreover, this flexible nanobody-based system can be adapted to load any compound, opening a range of new potential therapies with application to other diseases.

  19. Functional properties of monkey caudate neurons. III. Activities related to expectation of target and reward.

    PubMed

    Hikosaka, O; Sakamoto, M; Usui, S

    1989-04-01

    1. The present paper reports complex neural activities in the monkey caudate nucleus that precede and anticipate visual stimuli and reward in learned visuomotor paradigms. These activities were revealed typically in the delayed saccade task in which memory and anticipation were required. We classified these activities according to their relationships to the task. 2. Activity related to expectation of a cue (n = 46) preceded the presentation of a spot of light (target cue) that signified the future location of saccade target. When the target cue was delayed, the activity was prolonged accordingly. The same spot of light was preceded by no activity if it acted as a distracting stimulus. 3. The sustained activity (n = 80) was a tonic discharge starting after the target cue as if holding the spatial information. 4. The activity related to expectation of target (n = 109) preceded the appearance of the target whose location was cued previously. It started with or after a saccade to the cued target location and ended with the appearance of the target. The activity was greater when the target was expected to appear in the contralateral visual field. 5. The activity related to expectation of reward (n = 57) preceded a task-specific reward. It started with the appearance of the final target and ended with the reward. In most cases, the activity was nonselective for how the monkey obtained the reward, i.e., by visual fixation only, by a saccade, or by a hand movement. The activity was dependent partly on visual fixation. 6. A few neurons showed tonic activity selectively before lever release and are thus considered to be related to the preparation of hand movements. 7. The activity related to breaking fixation (n = 33) occurred phasically if the monkey broke fixation, aborting the trial. 8. Activity related to reward (n = 104) was a phasic discharge that occurred before or after a reward of water was delivered. The activity was not simply related to a specific movement

  20. Application of Fisher fusion techniques to improve the individual performance of sonar computer-aided detection/computer-aided classification (CAD/CAC) algorithms

    NASA Astrophysics Data System (ADS)

    Ciany, Charles M.; Zurawski, William C.

    2009-05-01

    Raytheon has extensively processed high-resolution sidescan sonar images with its CAD/CAC algorithms to provide classification of targets in a variety of shallow underwater environments. The Raytheon CAD/CAC algorithm is based on non-linear image segmentation into highlight, shadow, and background regions, followed by extraction, association, and scoring of features from candidate highlight and shadow regions of interest (ROIs). The targets are classified by thresholding an overall classification score, which is formed by summing the individual feature scores. The algorithm performance is measured in terms of probability of correct classification as a function of false alarm rate, and is determined by both the choice of classification features and the manner in which the classifier rates and combines these features to form its overall score. In general, the algorithm performs very reliably against targets that exhibit "strong" highlight and shadow regions in the sonar image- i.e., both the highlight echo and its associated shadow region from the target are distinct relative to the ambient background. However, many real-world undersea environments can produce sonar images in which a significant percentage of the targets exhibit either "weak" highlight or shadow regions in the sonar image. The challenge of achieving robust performance in these environments has traditionally been addressed by modifying the individual feature scoring algorithms to optimize the separation between the corresponding highlight or shadow feature scores of targets and non-targets. This study examines an alternate approach that employs principles of Fisher fusion to determine a set of optimal weighting coefficients that are applied to the individual feature scores before summing to form the overall classification score. The results demonstrate improved performance of the CAD/CAC algorithm on at-sea data sets.

  1. A new antibiotic with potent activity targets MscL.

    PubMed

    Iscla, Irene; Wray, Robin; Blount, Paul; Larkins-Ford, Jonah; Conery, Annie L; Ausubel, Frederick M; Ramu, Soumya; Kavanagh, Angela; Huang, Johnny X; Blaskovich, Mark A; Cooper, Matthew A; Obregon-Henao, Andres; Orme, Ian; Tjandra, Edwin S; Stroeher, Uwe H; Brown, Melissa H; Macardle, Cindy; van Holst, Nick; Ling Tong, Chee; Slattery, Ashley D; Gibson, Christopher T; Raston, Colin L; Boulos, Ramiz A

    2015-07-01

    The growing problem of antibiotic-resistant bacteria is a major threat to human health. Paradoxically, new antibiotic discovery is declining, with most of the recently approved antibiotics corresponding to new uses for old antibiotics or structurally similar derivatives of known antibiotics. We used an in silico approach to design a new class of nontoxic antimicrobials for the bacteria-specific mechanosensitive ion channel of large conductance, MscL. One antimicrobial of this class, compound 10, is effective against methicillin-resistant Staphylococcus aureus with no cytotoxicity in human cell lines at the therapeutic concentrations. As predicted from in silico modeling, we show that the mechanism of action of compound 10 is at least partly dependent on interactions with MscL. Moreover we show that compound 10 cured a methicillin-resistant S. aureus infection in the model nematode Caenorhabditis elegans. Our work shows that compound 10, and other drugs that target MscL, are potentially important therapeutics against antibiotic-resistant bacterial infections.

  2. A new antibiotic with potent activity targets MscL

    PubMed Central

    Iscla, Irene; Wray, Robin; Blount, Paul; Larkins-Ford, Jonah; Conery, Annie L; Ausubel, Frederick M; Ramu, Soumya; Kavanagh, Angela; Huang, Johnny X; Blaskovich, Mark A; Cooper, Matthew A; Obregon-Henao, Andres; Orme, Ian; Tjandra, Edwin S; Stroeher, Uwe H; Brown, Melissa H; Macardle, Cindy; van Holst, Nick; Ling Tong, Chee; Slattery, Ashley D; Gibson, Christopher T; Raston, Colin L; Boulos, Ramiz A

    2015-01-01

    The growing problem of antibiotic-resistant bacteria is a major threat to human health. Paradoxically, new antibiotic discovery is declining, with most of the recently approved antibiotics corresponding to new uses for old antibiotics or structurally similar derivatives of known antibiotics. We used an in silico approach to design a new class of nontoxic antimicrobials for the bacteria-specific mechanosensitive ion channel of large conductance, MscL. One antimicrobial of this class, compound 10, is effective against methicillin-resistant Staphylococcus aureus with no cytotoxicity in human cell lines at the therapeutic concentrations. As predicted from in silico modeling, we show that the mechanism of action of compound 10 is at least partly dependent on interactions with MscL. Moreover we show that compound 10 cured a methicillin-resistant S. aureus infection in the model nematode Caenorhabditis elegans. Our work shows that compound 10, and other drugs that target MscL, are potentially important therapeutics against antibiotic-resistant bacterial infections. PMID:25649856

  3. Application of fusion algorithms for computer aided detection and classification of bottom mines to synthetic aperture sonar test data

    NASA Astrophysics Data System (ADS)

    Ciany, Charles M.; Zurawski, William C.

    2006-05-01

    Over the past several years, Raytheon Company has adapted its Computer Aided Detection/Computer-Aided Classification (CAD/CAC) algorithm to process side-scan sonar imagery taken in both the Very Shallow Water (VSW) and Shallow Water (SW) operating environments. This paper describes the further adaptation of this CAD/CAC algorithm to process Synthetic Aperture Sonar (SAS) image data taken by an Autonomous Underwater Vehicle (AUV). The tuning of the CAD/CAC algorithm for the vehicle's sonar is described, the resulting classifier performance is presented, and the fusion of the classifier outputs with those of another CAD/CAC processor is evaluated. The fusion algorithm accepts the classification confidence levels and associated contact locations from the different CAD/CAC algorithms, clusters the contacts based on the distance between their locations, and then declares a valid target when a clustered contact passes a prescribed fusion criterion. Three different fusion criteria are evaluated: the first based on thresholding the sum of the confidence factors for the clustered contacts, the second based on simple binary combinations of the multiple CAD/CAC processor outputs, and the third based on the Fisher Discriminant. The resulting performance of the three fusion algorithms is compared, and the overall performance benefit of a significant reduction of false alarms at high correct classification probabilities is quantified.

  4. Adaptive three-dimensional range-crossrange-frequency filter processing string for sea mine classification in side scan sonar imagery

    NASA Astrophysics Data System (ADS)

    Aridgides, Tom; Fernandez, Manuel F.; Dobeck, Gerald J.

    1997-07-01

    An automatic, robust, adaptive clutter suppression, predetection level fusion, sea mine detection and classification processing string has been developed and applied to shallow water side-scan sonar imagery data. The overall processing string includes pre-processing string includes pre-processing, adaptive clutter filtering (ACF), 2D normalization, detection, feature extraction and classification processing blocks. The pre-processing block contains automatic gain control, data decimation and data alignment processing. The ACF is a multi-dimensional adaptive linear FIR filter, optimal in the least squares sense, for simultaneous background clutter suppression and preservation of an average peak target signature. After data alignment, using a 3D ACF enables simultaneous multiple frequency data fusion and clutter suppression in the composite frequency-range-crossrange domain. Following 2D normalization, the detection consists of thresholding, clustering of exceedances and limiting their number. Finally, features are extracted and a orthogonalization transformation is applied to the data, enabling an efficient application of the optimal log-likelihood-ratio-test (LLRT) classification rule. The utility of the overall processing string was demonstrated with two side-scan sonar data sets. The ACF, feature orthogonalization, LLRT-based classification processing string provided average probability of correct mine classification and false alarm rate performance exceeding the one obtained when utilizing an expert sonar operator. The overall processing string can be easily implemented in real-time using COTS technology.

  5. Systematic mining of analog series with related core structures in multi-target activity space.

    PubMed

    Gupta-Ostermann, Disha; Hu, Ye; Bajorath, Jürgen

    2013-08-01

    We have aimed to systematically extract analog series with related core structures from multi-target activity space to explore target promiscuity of closely related analogous. Therefore, a previously introduced SAR matrix structure was adapted and further extended for large-scale data mining. These matrices organize analog series with related yet distinct core structures in a consistent manner. High-confidence compound activity data yielded more than 2,300 non-redundant matrices capturing 5,821 analog series that included 4,288 series with multi-target and 735 series with multi-family activities. Many matrices captured more than three analog series with activity against more than five targets. The matrices revealed a variety of promiscuity patterns. Compound series matrices also contain virtual compounds, which provide suggestions for compound design focusing on desired activity profiles.

  6. Sidescan sonar as a tool for detection of demersal fish habitats

    USGS Publications Warehouse

    Able, Kenneth W.; Twichell, David C.; Grimes, Churchill B.; Jones, R. S.

    1987-01-01

    Sidescan sonar can be an effective tool for the determination of the habitat distribution of commercially important species.  This technique has the advantage of rapidly mapping large areas of the seafloor.  Sidescan images (sonographs) may also help to identify appropriate fishing gears for different types of seafloor or areas to be avoided with certain types of gears.  During the early stages of exploration, verification of sidescan sonar sonographs is critical to successful identification of important habitats.  Tilefishes (Lopholatilus and Caulolatilus) are especially good target species because the construct large burrows in the seafloor or live around boulders, both of which are easily detectable on sonographs.  In some special circumstances the estimates of tilefish burrow densities from sonographs can be used to estimate standing stock. In many localities the burrow and boulder habitats of tilefish are shared with other commercially important species such as American lobsters, Homarus americanus; cusk, Brosme brosme; and ocean pout, Macrozoarces americanus.

  7. Fusion of sea mine detection and classification processing strings for sonar imagery

    NASA Astrophysics Data System (ADS)

    Aridgides, Tom; Fernandez, Manuel F.; Dobeck, Gerald J.

    2000-08-01

    An advanced, automatic, adaptive clutter suppression, sea mine detection, classification and fusion processing string has been developed and tested with new sonar imagery data. The overall CAD/CAC string includes pre-processing, adaptive clutter filtering (ACF), normalization, detection , features extraction, classification and fusion processing blocks. The ACF is a multi-dimensional adaptive linear FIR filter, optimal in the Least Squares sense, and is applied to low- resolution data. It performs simultaneous background clutter suppression and preservation of an average peak target signature. Following 2D normalization, the detection consists of thresholding, clustering of exceedances and limiting the number of detections. Subsequently, features are extracted from high-resolution input data and an orthogonalization transformation is applied to the features, enabling an efficient application of the optimal log- likelihood-ratio-test (LLRT) classification rule. Finally, the classified objects of three processing strings, developed by 3 different research teams, are fused, using a variety of fusion rules, including logic-based and a novel orthogonal LLRT-base done. The utility of the overall processing string and their fusion was demonstrated with high-resolution side-scan sonar imagery from a difficult shallow water environment. The processing string classification performance was optimized by appropriately selecting a subset of the original feature set. The overall CAD/CAC processing string fusion result in improved mine classification capability, providing up to a four-fold false alarm rate reduction, compared to the best single CAD/CAC processing string results.

  8. Target identification for biologically active small molecules using chemical biology approaches.

    PubMed

    Lee, Heesu; Lee, Jae Wook

    2016-09-01

    The identification and validation of the targets of biologically active molecules is an important step in the field of chemical biology. While recent advances in proteomic and genomic technology have accelerated this identification process, the discovery of small molecule targets remains the most challenging step. A general method for the identification of these small molecule targets has not yet been established. To overcome the difficulty in target identification, new technology derived from the fields of genomics, proteomics, and bioinformatics has been developed. To date, pull-down methods using small molecules immobilized on a solid support followed by mass spectrometry have been the most successful approach. Here, we discuss current procedures for target identification. We also review the most recent target identification approaches and present several examples that illustrate advanced target identification technology.

  9. Hulu Sungai Perak Bed Sediment Mapping Using Underwater Acoustic Sonar

    NASA Astrophysics Data System (ADS)

    Arriafdi, N.; Zainon, O.; Din, U.; Rasid, A. W.; Mat Amin, Z.; Othman, R.; Mardi, A. S.; Mahmud, R.; Sulaiman, N.

    2016-09-01

    Development in acoustic survey techniques in particular side scan sonar have revolutionized the way we are able to image, map and understand the riverbed environment. It is now cost effective to image large areas of the riverbed using these techniques and the backscatter image created from surveys provides base line data from which thematic maps of the riverbed environment including maps of morphological geology, can be derived when interpreted in conjunction with in situ sampling data. This article focuses on investigation characteristics of sediments and correlation of side scan backscatter image with signal strength. The interpretation of acoustic backscatter rely on experienced interpretation by eye of grey scale images produced from the data. A 990F Starfish Side Scan Sonar was used to collect and develop a series of sonar images along 6 km of Hulu Sungai Perak. Background sediments could be delineated accurately and the image textures could be linked to the actual river floor appearance through grab sampling. A major difference was found in the acoustic returns from the two research area studies: the upstream area shows much rougher textures. This is due to an actual differences in riverbed roughness, caused by a difference in bottom currents and sediment dynamics in the two areas. The highest backscatter correlates with coarsest and roughness sediment. Result suggest that image based backscatter classification shows considerable promise for interpretation of side scan sonar data for the production of geological maps.

  10. Robust feature detection using sonar sensors for mobile robots

    NASA Astrophysics Data System (ADS)

    Choi, Jinwoo; Ahn, Sunghwan; Chung, Wan Kyun

    2005-12-01

    Sonar sensor is an attractive tool for the SLAM of mobile robot because of their economic aspects. This cheap sensor gives relatively accurate range readings if disregarding angular uncertainty and specular reflections. However, these defects make feature detection difficult for the most part of the SLAM. This paper proposed a robust sonar feature detection algorithm. This algorithm gives feature detection methods for both point features and line features. The point feature detection method was based on the TBF scheme. Moreover, three additional processes improved the performance of feature detection as follows; 1) stable intersections, 2) efficient sliding window update and 3) removal of the false point features on the wall. The line feature detection method was based on the basic property of adjacent sonar sensors. Along the line feature, three adjacent sonar sensors gave similar range readings. Using this sensor property, it proposed a novel algorithm for line feature detection, which is simple and the feature can be obtained by using only current sensor data. The proposed feature detection algorithm gives a good solution for the SLAM of mobile robots because it gives accurate feature information for both the point and line features even with sensor errors. Furthermore, a sufficient number of features are available to correct mobile robot pose. Experimental results for point feature and line feature detection demonstrate the performance of the proposed algorithm in a home-like environment.

  11. Enhanced Sidescan-Sonar Imagery Offshore of Southeastern Massachusetts

    USGS Publications Warehouse

    Poppe, Lawrence J.; McMullen, Kate Y.; Williams, S. Jeffress; Ackerman, Seth D.; Glomb, K.A.; Forfinski, N.A.

    2008-01-01

    The U.S. Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), and Massachusetts Office of Coastal Zone Management (CZM) have been working cooperatively to map and study the coastal sea floor. The sidescan-sonar imagery collected during NOAA hydrographic surveys has been included as part of these studies. However, the original sonar imagery contains tonal artifacts from environmental noise (for example, sea state), equipment settings (for example, power and gain changes), and processing (for example, inaccurate cross-track and line-to-line normalization), which impart a quilt-like patchwork appearance to the mosaics. These artifacts can obscure the normalized backscatter properties of the sea floor. To address this issue, sidescan-sonar imagery from surveys H11076 and H11079 offshore of southeastern Massachusetts was enhanced by matching backscatter tones of adjacent sidescan-sonar lines. These mosaics provide continuous grayscale perspectives of the backscatter, more accurately reveal the sea-floor geologic trends, and minimize the environment-, acquisition-, and processing-related noise.

  12. [Nutrition and physical activity: two targets for cancer prevention].

    PubMed

    Thibault, Ronan; Dupertuis, Yves M; Belabed, Linda; Pichard, Claude

    2010-05-26

    The links between nutrition and cancer onset are now well established by epidemiological studies. The scientific evidence is presented in a report of the World Cancer Research Foundation (WCRF). Protective factors towards overall cancer risk are fruit and vegetable consumption and physical activity. Overweight and obesity, intakes of alcoholic beverage, fat, salt, high temperature cooked and processed red meat, increase cancer risk. In addition, beta-carotene systematic supplementation could increase lung cancer risk in smokers. As optimal controlling of these risk factors can decrease cancer mortality by 25%, nutritional counselling must be integrated in the global strategy of primary and secondary prevention of cancers.

  13. Nrf2 activation as target to implement therapeutic treatments

    PubMed Central

    Bocci, Velio; Valacchi, Giuseppe

    2015-01-01

    A chronic increase of oxidative stress is typical of serious pathologies such as myocardial infarction, stroke, chronic limb ischemia, chronic obstructive pulmonary disease (COPD), type II-diabetes, age-related macular degeneration leads to an epic increase of morbidity and mortality in all countries of the world. The initial inflammation followed by an excessive release of reactive oxygen species (ROS) implies a diffused cellular injury that needs to be corrected by an inducible expression of the innate detoxifying and antioxidant system. The transcription factor Nrf2, when properly activated, is able to restore a redox homeostasis and possibly improve human health. PMID:25699252

  14. Target cell-specific modulation of neuronal activity by astrocytes

    NASA Astrophysics Data System (ADS)

    Kozlov, A. S.; Angulo, M. C.; Audinat, E.; Charpak, S.

    2006-06-01

    Interaction between astrocytes and neurons enriches the behavior of brain circuits. By releasing glutamate and ATP, astrocytes can directly excite neurons and modulate synaptic transmission. In the rat olfactory bulb, we demonstrate that the release of GABA by astrocytes causes long-lasting and synchronous inhibition of mitral and granule cells. In addition, astrocytes release glutamate, leading to a selective activation of granule-cell NMDA receptors. Thus, by releasing excitatory and inhibitory neurotransmitters, astrocytes exert a complex modulatory control on the olfactory network. glutamate | GABA | inhibition | olfactory bulb | synchronization

  15. NRF2 Activation as Target to Implement Therapeutic Treatments

    NASA Astrophysics Data System (ADS)

    Bocci, Velio; Valacchi, Giuseppe

    2015-02-01

    A chronic increase of oxidative stress is typical of serious pathologies such as myocardial infarction, stroke, chronic limb ischemia, chronic obstructive pulmonary disease (COPD), type II-diabetes, age-related macular degeneration leads to an epic increase of morbidity and mortality in all countries of the world. The initial inflammation followed by an excessive release of reactive oxygen species (ROS) implies a diffused cellular injury that needs to be corrected by an inducible expression of the innate detoxifying and antioxidant system. The transcription factor Nrf2, when properly activated, is able to restore a redox homeostasis and possibly improve human health.

  16. Mitochondrially targeted p53 has tumor suppressor activities in vivo.

    PubMed

    Talos, Flaminia; Petrenko, Oleksi; Mena, Patricio; Moll, Ute M

    2005-11-01

    Complex proapoptotic functions are essential for the tumor suppressor activity of p53. We recently described a novel transcription-independent mechanism that involves a rapid proapoptotic action of p53 at the mitochondria and executes the shortest known circuitry of p53 death signaling. Here, we examine if this p53-dependent mitochondrial program could be exploited for tumor suppression in vivo. To test this, we engage Emu-Myc transgenic mice, a well-established model of p53-dependent lymphomagenesis. We show that exclusive delivery of p53 to the outer mitochondrial membrane confers a significant growth disadvantage on Emu-Myc-transformed B-cells of p53-deficient or alternate reading frame-deficient genotypes, resulting in efficient induction of apoptosis and impinged proliferation. Conversely, normal cells from thymus, spleen, and bone marrow showed poor infectivity with these viruses. This proof-of-principle experiment shows that exclusive reliance on the direct mitochondrial program exerts a significant tumor suppressor activity in vivo. Our in vivo data on the direct mitochondrial apoptotic p53 program lays the groundwork to further investigate its efficacy and safety and to address its possible therapeutic value in the future.

  17. Tracking moving targets in complex environments by fusing active and passive sensors

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, Ben G.; Liu, Li; Wang, Yun; Cheng, Zhanqi

    2007-04-01

    We present a novel algorithm for tracking with ladar sensors to aid in navigation, guidance and control systems, suitable for applications to unmanned air vehicles. The methods we employ are based on Bayesian segmentation, optical flow, active contour and Bayesian particle tracking. The algorithm herein holds several significant advantages over traditional tracking methods. The first step in the process is the optimal segmentation of images to enhance the targets and extract them from background clutter and noise. The Bayesian approach to segmentation allows the use of intensity (passive) and range (active) imagery to find targets. Optical flow generalizes and improves correlation techniques for locating objects within a frame, allowing for aspect angle and range changes. With optical flow, we may infer relative velocities on a pixel-by-pixel basis. Active contours are ideally suited to both target-sparse and target-rich environments. The energy approach to determining contours allows the merging and separating of potential targets in an automatic manner. Bayesian particle tracking techniques are used to track the contours over time. The algorithm is tested successfully on experimental and simulated ladar data (using both intensity and range data) as well as sequences of video imageries. The streamlined processing, from obtaining the image data (of size 805x148 pixels) to detecting the moving target to wrapping an active contour on the target, takes less than one second of clock time and provides very accurate predictions of the target location in future frames.

  18. Reliability of fish size estimates obtained from multibeam imaging sonar

    USGS Publications Warehouse

    Hightower, Joseph E.; Magowan, Kevin J.; Brown, Lori M.; Fox, Dewayne A.

    2013-01-01

    Multibeam imaging sonars have considerable potential for use in fisheries surveys because the video-like images are easy to interpret, and they contain information about fish size, shape, and swimming behavior, as well as characteristics of occupied habitats. We examined images obtained using a dual-frequency identification sonar (DIDSON) multibeam sonar for Atlantic sturgeon Acipenser oxyrinchus oxyrinchus, striped bass Morone saxatilis, white perch M. americana, and channel catfish Ictalurus punctatus of known size (20–141 cm) to determine the reliability of length estimates. For ranges up to 11 m, percent measurement error (sonar estimate – total length)/total length × 100 varied by species but was not related to the fish's range or aspect angle (orientation relative to the sonar beam). Least-square mean percent error was significantly different from 0.0 for Atlantic sturgeon (x̄  =  −8.34, SE  =  2.39) and white perch (x̄  = 14.48, SE  =  3.99) but not striped bass (x̄  =  3.71, SE  =  2.58) or channel catfish (x̄  = 3.97, SE  =  5.16). Underestimating lengths of Atlantic sturgeon may be due to difficulty in detecting the snout or the longer dorsal lobe of the heterocercal tail. White perch was the smallest species tested, and it had the largest percent measurement errors (both positive and negative) and the lowest percentage of images classified as good or acceptable. Automated length estimates for the four species using Echoview software varied with position in the view-field. Estimates tended to be low at more extreme azimuthal angles (fish's angle off-axis within the view-field), but mean and maximum estimates were highly correlated with total length. Software estimates also were biased by fish images partially outside the view-field and when acoustic crosstalk occurred (when a fish perpendicular to the sonar and at relatively close range is detected in the side lobes of adjacent beams). These sources of

  19. Decoding Target Distance and Saccade Amplitude from Population Activity in the Macaque Lateral Intraparietal Area (LIP)

    PubMed Central

    Bremmer, Frank; Kaminiarz, Andre; Klingenhoefer, Steffen; Churan, Jan

    2016-01-01

    Primates perform saccadic eye movements in order to bring the image of an interesting target onto the fovea. Compared to stationary targets, saccades toward moving targets are computationally more demanding since the oculomotor system must use speed and direction information about the target as well as knowledge about its own processing latency to program an adequate, predictive saccade vector. In monkeys, different brain regions have been implicated in the control of voluntary saccades, among them the lateral intraparietal area (LIP). Here we asked, if activity in area LIP reflects the distance between fovea and saccade target, or the amplitude of an upcoming saccade, or both. We recorded single unit activity in area LIP of two macaque monkeys. First, we determined for each neuron its preferred saccade direction. Then, monkeys performed visually guided saccades along the preferred direction toward either stationary or moving targets in pseudo-randomized order. LIP population activity allowed to decode both, the distance between fovea and saccade target as well as the size of an upcoming saccade. Previous work has shown comparable results for saccade direction (Graf and Andersen, 2014a,b). Hence, LIP population activity allows to predict any two-dimensional saccade vector. Functional equivalents of macaque area LIP have been identified in humans. Accordingly, our results provide further support for the concept of activity from area LIP as neural basis for the control of an oculomotor brain-machine interface.

  20. Decoding Target Distance and Saccade Amplitude from Population Activity in the Macaque Lateral Intraparietal Area (LIP)

    PubMed Central

    Bremmer, Frank; Kaminiarz, Andre; Klingenhoefer, Steffen; Churan, Jan

    2016-01-01

    Primates perform saccadic eye movements in order to bring the image of an interesting target onto the fovea. Compared to stationary targets, saccades toward moving targets are computationally more demanding since the oculomotor system must use speed and direction information about the target as well as knowledge about its own processing latency to program an adequate, predictive saccade vector. In monkeys, different brain regions have been implicated in the control of voluntary saccades, among them the lateral intraparietal area (LIP). Here we asked, if activity in area LIP reflects the distance between fovea and saccade target, or the amplitude of an upcoming saccade, or both. We recorded single unit activity in area LIP of two macaque monkeys. First, we determined for each neuron its preferred saccade direction. Then, monkeys performed visually guided saccades along the preferred direction toward either stationary or moving targets in pseudo-randomized order. LIP population activity allowed to decode both, the distance between fovea and saccade target as well as the size of an upcoming saccade. Previous work has shown comparable results for saccade direction (Graf and Andersen, 2014a,b). Hence, LIP population activity allows to predict any two-dimensional saccade vector. Functional equivalents of macaque area LIP have been identified in humans. Accordingly, our results provide further support for the concept of activity from area LIP as neural basis for the control of an oculomotor brain-machine interface. PMID:27630547

  1. Decoding Target Distance and Saccade Amplitude from Population Activity in the Macaque Lateral Intraparietal Area (LIP).

    PubMed

    Bremmer, Frank; Kaminiarz, Andre; Klingenhoefer, Steffen; Churan, Jan

    2016-01-01

    Primates perform saccadic eye movements in order to bring the image of an interesting target onto the fovea. Compared to stationary targets, saccades toward moving targets are computationally more demanding since the oculomotor system must use speed and direction information about the target as well as knowledge about its own processing latency to program an adequate, predictive saccade vector. In monkeys, different brain regions have been implicated in the control of voluntary saccades, among them the lateral intraparietal area (LIP). Here we asked, if activity in area LIP reflects the distance between fovea and saccade target, or the amplitude of an upcoming saccade, or both. We recorded single unit activity in area LIP of two macaque monkeys. First, we determined for each neuron its preferred saccade direction. Then, monkeys performed visually guided saccades along the preferred direction toward either stationary or moving targets in pseudo-randomized order. LIP population activity allowed to decode both, the distance between fovea and saccade target as well as the size of an upcoming saccade. Previous work has shown comparable results for saccade direction (Graf and Andersen, 2014a,b). Hence, LIP population activity allows to predict any two-dimensional saccade vector. Functional equivalents of macaque area LIP have been identified in humans. Accordingly, our results provide further support for the concept of activity from area LIP as neural basis for the control of an oculomotor brain-machine interface. PMID:27630547

  2. High resolution sea floor bathymetry using high frequency multibeam sonar and structured light laser imaging

    NASA Astrophysics Data System (ADS)

    Roman, C.; Inglis, G.; Smart, C.; Vaughn, I.; Carey, S.

    2011-12-01

    Detailed bathymetric maps of the sea floor with centimeter level resolution can be produced by underwater vehicles using multibeam sonars and structured light laser imaging. Over spatial scales up to tens of thousands of square meters it is possible to produce maps gridded to sub centimeter levels. This level of accuracy demands detailed treatments of the sensor relative data, the vehicle navigation data and the vehicle to sensor position and rotational offsets. The presented results will show comparisons between these two sensor modalities. Data have a been collected during recent field programs to the Kolumbo volcanic crater and the Southern Aegean Sea. Our data processing and map making technique is based on the Simultaneous Localization and Mapping (SLAM) concept, which is an active research area in both the marine and land robotics communities. The SLAM method provides a common framework for addressing both sensor and navigation errors in a self consistent manner. Using automated patch registration and filter techniques both the multibeam and laser data can be processed by the same algorithm. Structured light imaging has been a common machine vision technique for 3D shape estimation in industrial applications, but has had limited use underwater. By using a camera to image a projected laser line on the sea floor it is possible to determine the 3D profile of the bottom with sub centimeter resolution. Sequential images taken during a survey can be processed and merged into a bathymetric map in a similar manner as individual multibeam sonar pings. The resulting maps can be gridded down to 2.5 millimeter resolution and clearly show objects just a few centimeters in size. The structured light data have been compared to multibeam sonar data taken with BlueView Technologies sonars operating at both 1375 kHz and 2250 kHz. Such high frequency sonars offer centimeter resolution over ranges to 30 and 10 meters respectively. The difference between the broader footprint

  3. Antimalarial activity enhancement in hydroxymethylcarbonyl (HMC) isostere-based dipeptidomimetics targeting malarial aspartic protease plasmepsin

    PubMed Central

    Hidaka, Koushi; Kimura, Tooru; Ruben, Adam J.; Uemura, Tsuyoshi; Kamiya, Mami; Kiso, Aiko; Okamoto, Tetsuya; Tsuchiya, Yumi; Hayashi, Yoshio; Freire, Ernesto; Kiso, Yoshiaki

    2015-01-01

    Plasmepsin (Plm) is a potential target for new antimalarial drugs, but most reported Plm inhibitors have relatively low antimalarial activities. We synthesized a series of dipeptide-type HIV protease inhibitors, which contain an allophenylnorstatine-dimethylthioproline scaffold to exhibit potent inhibitory activities against Plm II. Their activities against Plasmodium falciparum in the infected erythrocyte assay were largely different from those against the target enzyme. To improve the antimalarial activity of peptidomimetic Plm inhibitors, we attached substituents on a structure of the highly potent Plm inhibitor KNI-10006. Among the derivatives, we identified alkylamino compounds such as 44 (KNI-10283) and 47 (KNI-10538) with more than 15-fold enhanced antimalarial activity, to the sub-micromolar level, maintaining their potent Plm II inhibitory activity and low cytotoxicity. These results suggest that auxiliary substituents on a specific basic group contribute to deliver the inhibitors to the target Plm. PMID:18952439

  4. Target design considerations for high specific activity [{sup 11}C]O{sub 2}

    SciTech Connect

    Ferrieri, R.A.; Alexoff, D.L.; Schlyer, D.J.; McDonald, K.; Wolf, A.P.

    1993-12-31

    In the routine preparation of {sup 11}C-labeled compounds through N-[{sup 11}C]-methylation using [{sup 11}C]H{sub 3}I, total masses are always higher than synthesis mass contribution, suggesting that the target system contributes carrier carbon to the final product mass. This conclusion prompted this evaluation of target materials and target design for [{sup 11}C]O{sub 2} production. Ultimately, one is faced with the sprospect of compromising between [{sup 11}C]O{sub 2} specific activity and the amount that can be extracted from the target after a reasonable irradiation time.

  5. Estimated Tissue and Blood N(2) Levels and Risk of Decompression Sickness in Deep-, Intermediate-, and Shallow-Diving Toothed Whales during Exposure to Naval Sonar.

    PubMed

    Kvadsheim, P H; Miller, P J O; Tyack, P L; Sivle, L D; Lam, F P A; Fahlman, A

    2012-01-01

    Naval sonar has been accused of causing whale stranding by a mechanism which increases formation of tissue N(2) gas bubbles. Increased tissue and blood N(2) levels, and thereby increased risk of decompression sickness (DCS), is thought to result from changes in behavior or physiological responses during diving. Previous theoretical studies have used hypothetical sonar-induced changes in both behavior and physiology to model blood and tissue N(2) tension [Formula: see text], but this is the first attempt to estimate the changes during actual behavioral responses to sonar. We used an existing mathematical model to estimate blood and tissue N(2) tension [Formula: see text] from dive data recorded from sperm, killer, long-finned pilot, Blainville's beaked, and Cuvier's beaked whales before and during exposure to Low- (1-2 kHz) and Mid- (2-7 kHz) frequency active sonar. Our objectives were: (1) to determine if differences in dive behavior affects risk of bubble formation, and if (2) behavioral- or (3) physiological responses to sonar are plausible risk factors. Our results suggest that all species have natural high N(2) levels, with deep diving generally resulting in higher end-dive [Formula: see text] as compared with shallow diving. Sonar exposure caused some changes in dive behavior in both killer whales, pilot whales and beaked whales, but this did not lead to any increased risk of DCS. However, in three of eight exposure session with sperm whales, the animal changed to shallower diving, and in all these cases this seem to result in an increased risk of DCS, although risk was still within the normal risk range of this species. When a hypothetical removal of the normal dive response (bradycardia and peripheral vasoconstriction), was added to the behavioral response during model simulations, this led to an increased variance in the estimated end-dive N(2) levels, but no consistent change of risk. In conclusion, we cannot rule out the possibility that a combination

  6. Estimated Tissue and Blood N2 Levels and Risk of Decompression Sickness in Deep-, Intermediate-, and Shallow-Diving Toothed Whales during Exposure to Naval Sonar

    PubMed Central

    Kvadsheim, P. H.; Miller, P. J. O.; Tyack, P. L.; Sivle, L. D.; Lam, F. P. A.; Fahlman, A.

    2012-01-01

    Naval sonar has been accused of causing whale stranding by a mechanism which increases formation of tissue N2 gas bubbles. Increased tissue and blood N2 levels, and thereby increased risk of decompression sickness (DCS), is thought to result from changes in behavior or physiological responses during diving. Previous theoretical studies have used hypothetical sonar-induced changes in both behavior and physiology to model blood and tissue N2 tension PN2, but this is the first attempt to estimate the changes during actual behavioral responses to sonar. We used an existing mathematical model to estimate blood and tissue N2 tension PN2 from dive data recorded from sperm, killer, long-finned pilot, Blainville’s beaked, and Cuvier’s beaked whales before and during exposure to Low- (1–2 kHz) and Mid- (2–7 kHz) frequency active sonar. Our objectives were: (1) to determine if differences in dive behavior affects risk of bubble formation, and if (2) behavioral- or (3) physiological responses to sonar are plausible risk factors. Our results suggest that all species have natural high N2 levels, with deep diving generally resulting in higher end-dive PN2 as compared with shallow diving. Sonar exposure caused some changes in dive behavior in both killer whales, pilot whales and beaked whales, but this did not lead to any increased risk of DCS. However, in three of eight exposure session with sperm whales, the animal changed to shallower diving, and in all these cases this seem to result in an increased risk of DCS, although risk was still within the normal risk range of this species. When a hypothetical removal of the normal dive response (bradycardia and peripheral vasoconstriction), was added to the behavioral response during model simulations, this led to an increased variance in the estimated end-dive N2 levels, but no consistent change of risk. In conclusion, we cannot rule out the possibility that a combination of behavioral and physiological responses to sonar

  7. Design and Analysis of Hammerhead Ribozyme Activity Against an Artificial Gene Target

    PubMed Central

    Carter, James; Nawtaisong, Pruksa; Balaraman, Velmurugan; Fraser, Malcolm J.

    2014-01-01

    In vitro cleavage assays are routinely conducted to properly assess the catalytic activity of hammerhead ribozymes (HHR) against target RNA molecules like the dengue virus RNA genomes. These experiments are performed for initial assessment of HHR catalysis in a cell-free system and have been simplified by the substitution of agarose gel electrophoresis for SDS-PAGE. Substituting mobility assays enables the analysis of ribozymes in a more rapid fashion without radioisotopes. Here we describe the in vitro transcription of an HHR and corresponding target from T7-promoted plasmids into RNA molecules leading to the analysis of HHR activity against the RNA target by in vitro cleavage assays. PMID:24318886

  8. Targeted Proteomics Approaches To Monitor Microbial Activity In Basalt Aquifer

    NASA Astrophysics Data System (ADS)

    Paszczynski, A. J.; Paidisetti, R.

    2007-12-01

    Microorganisms play a major role in biogeochemical cycles of the Earth. Information regarding microbial community composition can be very useful for environmental monitoring since the short generation times of microorganisms allows them to respond rapidly to changing environmental conditions. Microbial mediated attenuation of toxic chemicals offers great potential for the restoration of contaminated environments in an ecologically acceptable manner. Current knowledge regarding the structure and functional activities of microbial communities is limited, but more information is being acquired every day through many genomic- and proteomic- based methods. As of today, only a small fraction of the Earth's microorganisms has been cultured, and so most of the information regarding the biodegradation and therapeutic potentials of these uncultured microorganisms remains unknown. Sequence analysis of DNA and/or RNA has been used for identifying specific microorganisms, to study the community composition, and to monitor gene expression providing limited information about metabolic state of given microbial system. Proteomic studies can reveal information regarding the real-time metabolic state of the microbial communities thereby aiding in understanding their interaction with the environment. In research described here the involvement of microbial communities in the degradation of anthropogenic contaminants such as trichloroethylene (TCE) was studied using mass spectrometry-based proteomics. The co- metabolic degradation of TCE in the groundwater of the Snake River Plain Aquifer at the Test Area North (TAN) site of Idaho National Laboratory (INL) was monitored by the characterization of peptide sequences of enzymes such as methane monooxygenases (MMOs). MMOs, expressed by methanotrophic bacteria are involved in the oxidation of methane and non-specific co-metabolic oxidation of TCE. We developed a time- course cell lysis method to release proteins from complex microbial

  9. Using targeted messaging to increase physical activity in older adults: a review.

    PubMed

    Ostrander, Rachel E; Thompson, Hilaire J; Demiris, George

    2014-09-01

    Physical activity has many benefits for older adults; however, motivating older adults to engage in and maintain optimal levels of physical activity can be challenging for health care providers. A comprehensive literature review was performed to determine whether any evidence-based methods of delivery or particular content for targeted messaging exist that result in actual improvements in physical activity of older adults. Findings of the review demonstrate that messaging directed toward older adults to be physically active resulted in improvements in physical activity up to 1 year. Across studies many different modes of message delivery were shown to be effective. Message content, whether tailored or not, resulted in significant increases in physical activity. There is evidence to support the use of environmentally mediated messaging (i.e., local walking paths) for stronger results. Targeting the client's stage of change, having an activity partner if preferred, and scheduling physical activity also contribute to improved effects.

  10. Hearing thresholds of a harbor porpoise (Phocoena phocoena) for sweeps (1-2 kHz and 6-7 kHz bands) mimicking naval sonar signals.

    PubMed

    Kastelein, Ronald A; Hoek, Lean; de Jong, Christ A F

    2011-05-01

    The distance at which active naval sonar signals can be heard by harbor porpoises depends, among other factors, on the hearing thresholds of the species for those signals. Therefore the hearing sensitivity of a harbor porpoise was determined for 1 s up-sweep and down-sweep signals, mimicking mid-frequency and low-frequency active sonar sweeps (MFAS, 6-7 kHz band; LFAS, 1-2 kHz band). The 1-2 kHz sweeps were also tested with harmonics, as sonars sometimes produce these as byproducts of the fundamental signal. The hearing thresholds for up-sweeps and down-sweeps within each sweep pair were similar. The 50% detection threshold sound pressure levels (broadband, averaged over the signal duration) of the 1-2 kHz and 6-7 kHz sweeps were 75 and 67 dB re 1 μPa(2), respectively. Harmonic deformation of the 1-2 kHz sweeps reduced the threshold to 59 dB re 1 μPa(2). This study shows that the presence of harmonics in sonar signals can increase the detectability of a signal by harbor porpoises, and that tonal audiograms may not accurately predict the audibility of sweeps. LFAS systems, when designed to produce signals without harmonics, can operate at higher source levels than MFAS systems, at similar audibility distances for porpoises.

  11. 3D Chirp Sonar Images on Fluid Migration Pathways and Their Implications on Seafloor Stability East of the Fangliao Submarine Canyon Offshore SW Taiwan

    NASA Astrophysics Data System (ADS)

    Lu, Y. W.; Liu, C. S.; Su, C. C.; Hsu, H. H.; Chen, Y. H.

    2015-12-01

    This study utilizes both chirp sonar images and coring results to investigate the unstable seafloor strata east of the Fangliao Submarine Canyon offshore southwestern Taiwan. We have constructed 3D chirp sonar images from a densely surveyed block to trace the attitude of an acoustic transparent layer and features caused by fluid activities. Based on the distribution of this transparent layer and fluid-related features, we suggest that this transparent layer forms a pathway for fluid migration which induces fluid-related characters such as acoustic blanking and fluid chimneys in the 3D chirp sonar images. Cored seafloor samples are used in this study to investigate the sediment compositions. The 210Pb activity profiles of the cores show oscillating and unsteady values at about 20~25 cm from core top. The bulk densities of the core samples in the same section (about 20~25 cm from core top) give values lower than those at deeper parts of the cores. These results indicate that the water content is much higher in the shallow sediments than in the deeper strata. From core sample analyses, we deduce that the local sediments are disturbed by liquefaction. From the analyses of 3D chirp sonar images and core data, we suggest that the seafloor east of the Fangliao Submarine Canyon is in an unstable condition, if disturbed by earthquakes, submarine landslides and gravity flows could be easily triggered and cause some geohazards, like breaking submarine cables during the 2006 Pingtung earthquake event.

  12. Drug target identification using network analysis: Taking active components in Sini decoction as an example

    PubMed Central

    Chen, Si; Jiang, Hailong; Cao, Yan; Wang, Yun; Hu, Ziheng; Zhu, Zhenyu; Chai, Yifeng

    2016-01-01

    Identifying the molecular targets for the beneficial effects of active small-molecule compounds simultaneously is an important and currently unmet challenge. In this study, we firstly proposed network analysis by integrating data from network pharmacology and metabolomics to identify targets of active components in sini decoction (SND) simultaneously against heart failure. To begin with, 48 potential active components in SND against heart failure were predicted by serum pharmacochemistry, text mining and similarity match. Then, we employed network pharmacology including text mining and molecular docking to identify the potential targets of these components. The key enriched processes, pathways and related diseases of these target proteins were analyzed by STRING database. At last, network analysis was conducted to identify most possible targets of components in SND. Among the 25 targets predicted by network analysis, tumor necrosis factor α (TNF-α) was firstly experimentally validated in molecular and cellular level. Results indicated that hypaconitine, mesaconitine, higenamine and quercetin in SND can directly bind to TNF-α, reduce the TNF-α-mediated cytotoxicity on L929 cells and exert anti-myocardial cell apoptosis effects. We envisage that network analysis will also be useful in target identification of a bioactive compound. PMID:27095146

  13. Simulation of a Novel Active Target for Neutron-Unbound State Measurements

    NASA Astrophysics Data System (ADS)

    Frank, Nathan; MoNA Collaboration

    2013-10-01

    Measurement of nuclei at extreme ratios of protons to neutrons is challenging due to the low production rate. New facilities will increase the production of neutron-rich isotopes, but still not reach the neutron dripline for heavier nuclei. We simulated a carbon-based active target system that could be constructed to both increase statistics while preserving the experimental resolution. This simulation is an adaptation of the in-house MoNA Collaboration C + + based simulation tool to extract the decay energy of neutron-unbound states. A number of experiments of this type have been carried out at the National Superconducting Cyclotron Laboratory (NSCL). In most experiments, we produce neutron-unbound nuclei by bombarding a Beryllium target with a radioactive beam. The nucleus of interest immediately decays into a charged particle and one or more neutrons. In this simulation, we have constructed a carbon-based active target that provides a measurement of energy loss, which is used to calculate the nuclear interaction point within the target. This additional information is used to improve the resolution or preserve the resolution of a thinner target while increasing statistics. This presentation will cover some aspects of the simulation process as well as show a resolution improvement of up to about 4 with a ~700 mg/cm2 active target compared to a Be-target. The simulation utilized experimental settings from published work. Work supported by National Science Foundation Grant #0969173.

  14. SoNar, a Highly Responsive NAD+/NADH Sensor, Allows High-Throughput Metabolic Screening of Anti-tumor Agents.

    PubMed

    Zhao, Yuzheng; Hu, Qingxun; Cheng, Feixiong; Su, Ni; Wang, Aoxue; Zou, Yejun; Hu, Hanyang; Chen, Xianjun; Zhou, Hai-Meng; Huang, Xinzhi; Yang, Kai; Zhu, Qian; Wang, Xue; Yi, Jing; Zhu, Linyong; Qian, Xuhong; Chen, Lixin; Tang, Yun; Loscalzo, Joseph; Yang, Yi

    2015-05-01

    The altered metabolism of tumor cells confers a selective advantage for survival and proliferation, and studies have shown that targeting such metabolic shifts may be a useful therapeutic strategy. We developed an intensely fluorescent, rapidly responsive, pH-resistant, genetically encoded sensor of wide dynamic range, denoted SoNar, for tracking cytosolic NAD(+) and NADH redox states in living cells and in vivo. SoNar responds to subtle perturbations of various pathways of energy metabolism in real time, and allowed high-throughput screening for new agents targeting tumor metabolism. Among > 5,500 unique compounds, we identified KP372-1 as a potent NQO1-mediated redox cycling agent that produced extreme oxidative stress, selectively induced cancer cell apoptosis, and effectively decreased tumor growth in vivo. This study demonstrates that genetically encoded sensor-based metabolic screening could serve as a valuable approach for drug discovery.

  15. 78 FR 70537 - Takes of Marine Mammals Incidental to Specified Activities; Target and Missile Launch Activities...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-26

    .... SUMMARY: NMFS has received a request from the U.S. Navy (Navy), Naval Air Warfare Center Weapons Division... conducted for testing new types of targets. Missiles vary from tactical and developmental weapons to target missiles used to test defensive strategies and other weapons systems. Up to 200 missiles may be...

  16. Acoustic and foraging behavior of a Baird's beaked whale, Berardius bairdii, exposed to simulated sonar.

    PubMed

    Stimpert, A K; DeRuiter, S L; Southall, B L; Moretti, D J; Falcone, E A; Goldbogen, J A; Friedlaender, A; Schorr, G S; Calambokidis, J

    2014-11-13

    Beaked whales are hypothesized to be particularly sensitive to anthropogenic noise, based on previous strandings and limited experimental and observational data. However, few species have been studied in detail. We describe the underwater behavior of a Baird's beaked whale (Berardius bairdii) from the first deployment of a multi-sensor acoustic tag on this species. The animal exhibited shallow (23 ± 15 m max depth), intermediate (324 ± 49 m), and deep (1138 ± 243 m) dives. Echolocation clicks were produced with a mean inter-click interval of approximately 300 ms and peak frequency of 25 kHz. Two deep dives included presumed foraging behavior, with echolocation pulsed sounds (presumed prey capture attempts) associated with increased maneuvering, and sustained inverted swimming during the bottom phase of the dive. A controlled exposure to simulated mid-frequency active sonar (3.5-4 kHz) was conducted 4 hours after tag deployment, and within 3 minutes of exposure onset, the tagged whale increased swim speed and body movement, and continued to show unusual dive behavior for each of its next three dives, one of each type. These are the first data on the acoustic foraging behavior in this largest beaked whale species, and the first experimental demonstration of a response to simulated sonar.

  17. Deployment of a WLCG network monitoring infrastructure based on the perfSONAR-PS technology

    NASA Astrophysics Data System (ADS)

    Campana, S.; Brown, A.; Bonacorsi, D.; Capone, V.; De Girolamo, D.; Casani, A. F.; Flix, J.; Forti, A.; Gable, I.; Gutsche, O.; Hesnaux, A.; Liu, S.; Lopez Munoz, F.; Magini, N.; McKee, S.; Mohammed, K.; Rand, D.; Reale, M.; Roiser, S.; Zielinski, M.; Zurawski, J.

    2014-06-01

    The WLCG infrastructure moved from a very rigid network topology, based on the MONARC model, to a more relaxed system, where data movement between regions or countries does not necessarily need to involve T1 centres. While this evolution brought obvious advantages, especially in terms of flexibility for the LHC experiment's data management systems, it also opened the question of how to monitor the increasing number of possible network paths, in order to provide a global reliable network service. The perfSONAR network monitoring system has been evaluated and agreed as a proper solution to cover the WLCG network monitoring use cases: it allows WLCG to plan and execute latency and bandwidth tests between any instrumented endpoint through a central scheduling configuration, it allows archiving of the metrics in a local database, it provides a programmatic and a web based interface exposing the tests results; it also provides a graphical interface for remote management operations. In this contribution we will present our activity to deploy a perfSONAR based network monitoring infrastructure, in the scope of the WLCG Operations Coordination initiative: we will motivate the main choices we agreed in terms of configuration and management, describe the additional tools we developed to complement the standard packages and present the status of the deployment, together with the possible future evolution.

  18. Acoustic and foraging behavior of a Baird's beaked whale, Berardius bairdii, exposed to simulated sonar.

    PubMed

    Stimpert, A K; DeRuiter, S L; Southall, B L; Moretti, D J; Falcone, E A; Goldbogen, J A; Friedlaender, A; Schorr, G S; Calambokidis, J

    2014-01-01

    Beaked whales are hypothesized to be particularly sensitive to anthropogenic noise, based on previous strandings and limited experimental and observational data. However, few species have been studied in detail. We describe the underwater behavior of a Baird's beaked whale (Berardius bairdii) from the first deployment of a multi-sensor acoustic tag on this species. The animal exhibited shallow (23 ± 15 m max depth), intermediate (324 ± 49 m), and deep (1138 ± 243 m) dives. Echolocation clicks were produced with a mean inter-click interval of approximately 300 ms and peak frequency of 25 kHz. Two deep dives included presumed foraging behavior, with echolocation pulsed sounds (presumed prey capture attempts) associated with increased maneuvering, and sustained inverted swimming during the bottom phase of the dive. A controlled exposure to simulated mid-frequency active sonar (3.5-4 kHz) was conducted 4 hours after tag deployment, and within 3 minutes of exposure onset, the tagged whale increased swim speed and body movement, and continued to show unusual dive behavior for each of its next three dives, one of each type. These are the first data on the acoustic foraging behavior in this largest beaked whale species, and the first experimental demonstration of a response to simulated sonar. PMID:25391309

  19. Acoustic and foraging behavior of a Baird's beaked whale, Berardius bairdii, exposed to simulated sonar

    PubMed Central

    Stimpert, A. K.; DeRuiter, S. L.; Southall, B. L.; Moretti, D. J.; Falcone, E. A.; Goldbogen, J. A.; Friedlaender, A.; Schorr, G. S.; Calambokidis, J.

    2014-01-01

    Beaked whales are hypothesized to be particularly sensitive to anthropogenic noise, based on previous strandings and limited experimental and observational data. However, few species have been studied in detail. We describe the underwater behavior of a Baird's beaked whale (Berardius bairdii) from the first deployment of a multi-sensor acoustic tag on this species. The animal exhibited shallow (23 ± 15 m max depth), intermediate (324 ± 49 m), and deep (1138 ± 243 m) dives. Echolocation clicks were produced with a mean inter-click interval of approximately 300 ms and peak frequency of 25 kHz. Two deep dives included presumed foraging behavior, with echolocation pulsed sounds (presumed prey capture attempts) associated with increased maneuvering, and sustained inverted swimming during the bottom phase of the dive. A controlled exposure to simulated mid-frequency active sonar (3.5–4 kHz) was conducted 4 hours after tag deployment, and within 3 minutes of exposure onset, the tagged whale increased swim speed and body movement, and continued to show unusual dive behavior for each of its next three dives, one of each type. These are the first data on the acoustic foraging behavior in this largest beaked whale species, and the first experimental demonstration of a response to simulated sonar. PMID:25391309

  20. Folate-conjugated polymer micelles for active targeting to cancer cells: preparation, in vitro evaluation of targeting ability and cytotoxicity

    NASA Astrophysics Data System (ADS)

    You, Jian; Li, Xin; de Cui, Fu; Du, Yong-Zhong; Yuan, Hong; Hu, Fu qiang

    2008-01-01

    To obtain an active-targeting carrier to cancer cells, folate-conjugated stearic acid grafted chitosan oligosaccharide (Fa-CSOSA) was synthesized by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling reaction. The substitution degree is 22.1%. The critical micelle concentrations (CMCs) of Fa-CSOSA were 0.017 and 0.0074 mg ml-1 in distilled water and PBS (pH 7.4), respectively. The average volume size range of Fa-CSOSA micelles was 60-120 nm. The targeting ability of Fa-CSOSA micelles was investigated against two kinds of cell lines (A549 and Hela), which have different amounts of folate receptors in their surface. The results indicated that Fa-CSOSA micelles presented a targeting ability to the cells (Hela) with a higher expression of folate receptor during a short-time incubation (<6 h). As incubation proceeded, the special spatial structure of the micelles gradually plays a main role in cellular internalization of the micelles. Good internalization of the micelles into both Hela and A549 cells was shown. Then, paclitaxel (PTX) was encapsulated into the micelles, and the content of PTX in the micelles was about 4.8% (w/w). The average volume size range of PTX-loaded micelles was 150-340 nm. Furthermore, the anti-tumor efficacy in vitro was investigated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) method. The IC50 of Taxol (a clinical formulation containing PTX) on A549 and Hela cells was 7.0 and 11.0 µg ml-1, respectively. The cytotoxicity of PTX-loaded micelles was improved sharply (IC50 on A549: 0.32 µg ml-1 IC50 on Hela: 0.268 µg ml-1). This is attributed to the increased intracellular delivery of the drug. The Fa-CSOSA micelles that are presented may be a promising active-targeting carrier candidate via folate mediation.

  1. Design and operation specifications of an active monitoring system for detecting southern resident killer whales

    SciTech Connect

    Deng, Zhiqun; Carlson, Thomas J.; Xu, Jinshan; Martinez, Jayson J.; Weiland, Mark A.; Mueller, Robert P.; Myers, Joshua R.; Jones, Mark E.

    2011-09-30

    Before final approval is given to the Snohomish County Public Utility District No. 1 for deploying the first tidal power devices in the United States in an open water environment, a system to manage the potential risk of injury to killer whales due to collision with moving turbine blades must be demonstrated. The Pacific Northwest National Laboratory (PNNL) is tasked with establishing the performance requirements for, constructing, and testing a prototype marine animal alert system for triggering temporary turbine shutdown when there is risk of collision with a killer whale. To develop a system that relies on active sonar two critical areas must be investigated - the target strength of killer whales and the frequency content of commercially available active sonar units. PNNL studied three target strength models: a simple model, the Fourier matching model, and the Kirchoff-ray mode model. Using target strength measurements of bottlenose dolphins obtained by previous researchers and assuming killer whales share similar morphology and structure, PNNL extrapolated the target strength of an adult killer whale 7.5 m in length at a frequency of 67 kHz. To study the frequency content of a commercially available sonar unit, direct measurements of the signal transmitted by the sonar were obtained by using a hydrophone connected to a data acquisition system in both laboratory and field conditions. The measurements revealed that in addition to the primary frequency of 200 kHz, there is a secondary frequency component at 90 kHz, which is within the hearing range of killer whales. The amplitude of the 90-kHz frequency component is above the hearing threshold of killer whales but below the threshold for potential injuries.

  2. Analysis of the temporal structure of fish echoes using the dolphin broadband sonar signal.

    PubMed

    Matsuo, Ikuo; Imaizumi, Tomohito; Akamatsu, Tomonari; Furusawa, Masahiko; Nishimori, Yasushi

    2009-07-01

    Behavioral experiments indicate that dolphins detect and discriminate prey targets through echolocating broadband sonar signals. The fish echo contains components from multiple reflections, including those from the swim bladder and other organs, and can be used for the identification of fish species and the estimation of fish abundance. In this paper, temporal structures were extracted from fish echoes using the cross-correlation function and the lowpass filter. First, the echo was measured from an anesthetized fish in a water tank. The number, reflector intensity, and echo duration were shown to be dependent on the species, individual, and orientation of the fish. In particular, the echo duration provided useful information on the fish body height and for species identification. Second, the echo was measured from the live fish suspended by nylon monofilament lines in the open sea. It was shown that this duration could be estimated regardless of whether or not the fish were moving.

  3. Pitchfork and Gprasp2 Target Smoothened to the Primary Cilium for Hedgehog Pathway Activation

    PubMed Central

    Jung, Bomi; Padula, Daniela; Burtscher, Ingo; Landerer, Cedric; Lutter, Dominik; Theis, Fabian; Messias, Ana C.; Geerlof, Arie; Sattler, Michael; Kremmer, Elisabeth; Boldt, Karsten; Ueffing, Marius; Lickert, Heiko

    2016-01-01

    The seven-transmembrane receptor Smoothened (Smo) activates all Hedgehog (Hh) signaling by translocation into the primary cilia (PC), but how this is regulated is not well understood. Here we show that Pitchfork (Pifo) and the G protein-coupled receptor associated sorting protein 2 (Gprasp2) are essential components of an Hh induced ciliary targeting complex able to regulate Smo translocation to the PC. Depletion of Pifo or Gprasp2 leads to failure of Smo translocation to the PC and lack of Hh target gene activation. Together, our results identify a novel protein complex that is regulated by Hh signaling and required for Smo ciliary trafficking and Hh pathway activation. PMID:26901434

  4. Pitchfork and Gprasp2 Target Smoothened to the Primary Cilium for Hedgehog Pathway Activation.

    PubMed

    Jung, Bomi; Padula, Daniela; Burtscher, Ingo; Landerer, Cedric; Lutter, Dominik; Theis, Fabian; Messias, Ana C; Geerlof, Arie; Sattler, Michael; Kremmer, Elisabeth; Boldt, Karsten; Ueffing, Marius; Lickert, Heiko

    2016-01-01

    The seven-transmembrane receptor Smoothened (Smo) activates all Hedgehog (Hh) signaling by translocation into the primary cilia (PC), but how this is regulated is not well understood. Here we show that Pitchfork (Pifo) and the G protein-coupled receptor associated sorting protein 2 (Gprasp2) are essential components of an Hh induced ciliary targeting complex able to regulate Smo translocation to the PC. Depletion of Pifo or Gprasp2 leads to failure of Smo translocation to the PC and lack of Hh target gene activation. Together, our results identify a novel protein complex that is regulated by Hh signaling and required for Smo ciliary trafficking and Hh pathway activation. PMID:26901434

  5. In vivo monitoring of cellular energy metabolism using SoNar, a highly responsive sensor for NAD(+)/NADH redox state.

    PubMed

    Zhao, Yuzheng; Wang, Aoxue; Zou, Yejun; Su, Ni; Loscalzo, Joseph; Yang, Yi

    2016-08-01

    NADH and its oxidized form NAD(+) have a central role in energy metabolism, and their concentrations are often considered to be among the most important readouts of metabolic state. Here, we present a detailed protocol to image and monitor NAD(+)/NADH redox state in living cells and in vivo using a highly responsive, genetically encoded fluorescent sensor known as SoNar (sensor of NAD(H) redox). The chimeric SoNar protein was initially developed by inserting circularly permuted yellow fluorescent protein (cpYFP) into the NADH-binding domain of Rex protein from Thermus aquaticus (T-Rex). It functions by binding to either NAD(+) or NADH, thus inducing protein conformational changes that affect its fluorescent properties. We first describe steps for how to establish SoNar-expressing cells, and then discuss how to use the system to quantify the intracellular redox state. This approach is sensitive, accurate, simple and able to report subtle perturbations of various pathways of energy metabolism in real time. We also detail the application of SoNar to high-throughput chemical screening of candidate compounds targeting cell metabolism in a microplate-reader-based assay, along with in vivo fluorescence imaging of tumor xenografts expressing SoNar in mice. Typically, the approximate time frame for fluorescence imaging of SoNar is 30 min for living cells and 60 min for living mice. For high-throughput chemical screening in a 384-well-plate assay, the whole procedure generally takes no longer than 60 min to assess the effects of 380 compounds on cell metabolism. PMID:27362337

  6. In vivo monitoring of cellular energy metabolism using SoNar, a highly responsive sensor for NAD(+)/NADH redox state.

    PubMed

    Zhao, Yuzheng; Wang, Aoxue; Zou, Yejun; Su, Ni; Loscalzo, Joseph; Yang, Yi

    2016-08-01

    NADH and its oxidized form NAD(+) have a central role in energy metabolism, and their concentrations are often considered to be among the most important readouts of metabolic state. Here, we present a detailed protocol to image and monitor NAD(+)/NADH redox state in living cells and in vivo using a highly responsive, genetically encoded fluorescent sensor known as SoNar (sensor of NAD(H) redox). The chimeric SoNar protein was initially developed by inserting circularly permuted yellow fluorescent protein (cpYFP) into the NADH-binding domain of Rex protein from Thermus aquaticus (T-Rex). It functions by binding to either NAD(+) or NADH, thus inducing protein conformational changes that affect its fluorescent properties. We first describe steps for how to establish SoNar-expressing cells, and then discuss how to use the system to quantify the intracellular redox state. This approach is sensitive, accurate, simple and able to report subtle perturbations of various pathways of energy metabolism in real time. We also detail the application of SoNar to high-throughput chemical screening of candidate compounds targeting cell metabolism in a microplate-reader-based assay, along with in vivo fluorescence imaging of tumor xenografts expressing SoNar in mice. Typically, the approximate time frame for fluorescence imaging of SoNar is 30 min for living cells and 60 min for living mice. For high-throughput chemical screening in a 384-well-plate assay, the whole procedure generally takes no longer than 60 min to assess the effects of 380 compounds on cell metabolism.

  7. Measuring and Reducing Off-Target Activities of Programmable Nucleases Including CRISPR-Cas9.

    PubMed

    Koo, Taeyoung; Lee, Jungjoon; Kim, Jin-Soo

    2015-06-01

    Programmable nucleases, which include zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and RNA-guided engineered nucleases (RGENs) repurposed from the type II clustered, regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) system are now widely used for genome editing in higher eukaryotic cells and whole organisms, revolutionising almost every discipline in biological research, medicine, and biotechnology. All of these nucleases, however, induce off-target mutations at sites homologous in sequence with on-target sites, limiting their utility in many applications including gene or cell therapy. In this review, we compare methods for detecting nuclease off-target mutations. We also review methods for profiling genome-wide off-target effects and discuss how to reduce or avoid off-target mutations.

  8. Technology Infusion of CodeSonar into the Space Network Ground Segment

    NASA Technical Reports Server (NTRS)

    Benson, Markland J.

    2009-01-01

    This slide presentation reviews the applicability of CodeSonar to the Space Network software. CodeSonar is a commercial off the shelf system that analyzes programs written in C, C++ or Ada for defects in the code. Software engineers use CodeSonar results as an input to the existing source code inspection process. The study is focused on large scale software developed using formal processes. The systems studied are mission critical in nature but some use commodity computer systems.

  9. Activation of mitogen-activated protein kinase by membrane-targeted Raf chimeras is independent of raft localization.

    PubMed

    Chen, X; Resh, M D

    2001-09-14

    Binding of proteins to the plasma membrane can be achieved with various membrane targeting motifs, including combinations of fatty acids, isoprenoids, and basic domains. In this study, we investigate whether attachment of different membrane targeting motifs influences the signaling capacity of membrane-bound signal transduction proteins by directing the proteins to different membrane microdomains. We used c-Raf-1 as a model for a signaling protein that is activated when membrane-bound. Three different membrane targeting motifs from K-Ras, Fyn, and Src proteins were fused to the N or C terminus of Raf-1. The ability of the modified Rafs to initiate MAPK signaling was then investigated. All three modified Raf-1 constructs activated MAPK to nearly equivalent levels. The extent of localization of the Raf-1 constructs to membrane microdomains known as rafts did not correlate with the level of MAPK activation. Moreover, treatment of cells with the raft disrupting drug methyl-beta-cyclodextrin (MbetaCD) caused activation of MAPK to levels equivalent to those achieved with membrane-targeted Raf constructs. The use of pharmacological agents as well as dominant negative mutants revealed that MAPK activation by MbetaCD proceeds via a phosphoinositide 3-kinase-dependent mechanism that is Ras/Raf-independent. We conclude that cholesterol depletion from the plasma membrane by MbetaCD constitutes an alternative pathway for activating MAPK.

  10. Percentile ranks of sonar fetal abdominal circumference measurements.

    PubMed

    Tamura, R K; Sabbagha, R E

    1980-11-01

    We present the percentile ranks of sonar fetal abdominal circumference (AC) measurements from 18 to 41 weeks' gestation. The ACs are derived from both longitudinal and cross-sectional ultrasonic studies of 200 low-risk pregnant women. The reproducibility of sonar AC falls within 2% of the mean value; this variation permits antenatal distinction of the fetus with a small AC (less than twenty-fifth percentile) or large (greater than eightieth percentile) reading. The fetal AC measurements add another dimension to the interpretation of cephalic growth, particularly in identifying macrosomic fetuses as well as those who are either asymmetrically or symmetrically undergrown. Additionally fetal AC measurements are useful as adjuncts to the diagnosis of hydrocephalus by quantitating the difference between cephalic and body size. In the presence of fetal ascites the AC also can be used to assess the severity and progression of the abnormality.

  11. Application of the reverberation-limited form of the sonar equation to dolphin echolocation.

    PubMed

    Au, W W

    1992-10-01

    The target detection range of two echolocating Atlantic Bottlenose dolphins as a function of target depth in Kaneohe Bay, Hawaii, was determined by Murchison [A. E. Murchison, Ph.D. dissertation, Univ. of Calif., Santa Cruz (1980)]. The threshold range decreased monotonically as the depth of the 6.35-cm-diam solid-steel sphere increased and approached the bottom. For the target lying on the bottom, the 50% correct detection threshold detection range was approximately 70 m. The scattering strength of the bottom in Kaneohe Bay at approximately the same location of the Murchison's experiment was recently measured using a simulated dolphin echolocation signal and a transducer tilted at the appropriate grazing angle. The bottom scattering strength along with the target strength of the 6.35-cm sphere and the dolphin threshold range were incorporated into the generalized form of the sonar equation for a reverberation-limited situation and a detection threshold of 4.0 dB was calculated. This detection threshold compared well with the 2.3 dB obtained in an experiment in which the dolphin was required to detect a target in the presence of a clutter screen.

  12. Cysteine Proteases: Modes of Activation and Future Prospects as Pharmacological Targets

    PubMed Central

    Verma, Sonia; Dixit, Rajnikant; Pandey, Kailash C.

    2016-01-01

    Proteolytic enzymes are crucial for a variety of biological processes in organisms ranging from lower (virus, bacteria, and parasite) to the higher organisms (mammals). Proteases cleave proteins into smaller fragments by catalyzing peptide bonds hydrolysis. Proteases are classified according to their catalytic site, and distributed into four major classes: cysteine proteases, serine proteases, aspartic proteases, and metalloproteases. This review will cover only cysteine proteases, papain family enzymes which are involved in multiple functions such as extracellular matrix turnover, antigen presentation, processing events, digestion, immune invasion, hemoglobin hydrolysis, parasite invasion, parasite egress, and processing surface proteins. Therefore, they are promising drug targets for various diseases. For preventing unwanted digestion, cysteine proteases are synthesized as zymogens, and contain a prodomain (regulatory) and a mature domain (catalytic). The prodomain acts as an endogenous inhibitor of the mature enzyme. For activation of the mature enzyme, removal of the prodomain is necessary and achieved by different modes. The pro-mature domain interaction can be categorized as protein–protein interactions (PPIs) and may be targeted in a range of diseases. Cysteine protease inhibitors are available that can block the active site but no such inhibitor available yet that can be targeted to block the pro-mature domain interactions and prevent it activation. This review specifically highlights the modes of activation (processing) of papain family enzymes, which involve auto-activation, trans-activation and also clarifies the future aspects of targeting PPIs to prevent the activation of cysteine proteases. PMID:27199750

  13. Cysteine Proteases: Modes of Activation and Future Prospects as Pharmacological Targets.

    PubMed

    Verma, Sonia; Dixit, Rajnikant; Pandey, Kailash C

    2016-01-01

    Proteolytic enzymes are crucial for a variety of biological processes in organisms ranging from lower (virus, bacteria, and parasite) to the higher organisms (mammals). Proteases cleave proteins into smaller fragments by catalyzing peptide bonds hydrolysis. Proteases are classified according to their catalytic site, and distributed into four major classes: cysteine proteases, serine proteases, aspartic proteases, and metalloproteases. This review will cover only cysteine proteases, papain family enzymes which are involved in multiple functions such as extracellular matrix turnover, antigen presentation, processing events, digestion, immune invasion, hemoglobin hydrolysis, parasite invasion, parasite egress, and processing surface proteins. Therefore, they are promising drug targets for various diseases. For preventing unwanted digestion, cysteine proteases are synthesized as zymogens, and contain a prodomain (regulatory) and a mature domain (catalytic). The prodomain acts as an endogenous inhibitor of the mature enzyme. For activation of the mature enzyme, removal of the prodomain is necessary and achieved by different modes. The pro-mature domain interaction can be categorized as protein-protein interactions (PPIs) and may be targeted in a range of diseases. Cysteine protease inhibitors are available that can block the active site but no such inhibitor available yet that can be targeted to block the pro-mature domain interactions and prevent it activation. This review specifically highlights the modes of activation (processing) of papain family enzymes, which involve auto-activation, trans-activation and also clarifies the future aspects of targeting PPIs to prevent the activation of cysteine proteases. PMID:27199750

  14. Targeted HIV-1 Latency Reversal Using CRISPR/Cas9-Derived Transcriptional Activator Systems

    PubMed Central

    Bialek, Julia K.; Dunay, Gábor A.; Voges, Maike; Schäfer, Carola; Spohn, Michael; Stucka, Rolf; Hauber, Joachim; Lange, Ulrike C.

    2016-01-01

    CRISPR/Cas9 technology is currently considered the most advanced tool for targeted genome engineering. Its sequence-dependent specificity has been explored for locus-directed transcriptional modulation. Such modulation, in particular transcriptional activation, has been proposed as key approach to overcome silencing of dormant HIV provirus in latently infected cellular reservoirs. Currently available agents for provirus activation, so-called latency reversing agents (LRAs), act indirectly through cellular pathways to induce viral transcription. However, their clinical performance remains suboptimal, possibly because reservoirs have diverse cellular identities and/or proviral DNA is intractable to the induced pathways. We have explored two CRISPR/Cas9-derived activator systems as targeted approaches to induce dormant HIV-1 proviral DNA. These systems recruit multiple transcriptional activation domains to the HIV 5’ long terminal repeat (LTR), for which we have identified an optimal target region within the LTR U3 sequence. Using this target region, we demonstrate transcriptional activation of proviral genomes via the synergistic activation mediator complex in various in culture model systems for HIV latency. Observed levels of induction are comparable or indeed higher than treatment with established LRAs. Importantly, activation is complete, leading to production of infective viral particles. Our data demonstrate that CRISPR/Cas9-derived technologies can be applied to counteract HIV latency and may therefore represent promising novel approaches in the quest for HIV elimination. PMID:27341108

  15. Targeting the RAS pathway by mitogen-activated protein kinase inhibitors.

    PubMed

    Kiessling, Michael K; Rogler, Gerhard

    2015-01-01

    Targeting of oncogenic driver mutations with small-molecule inhibitors resulted in powerful treatment options for cancer patients in recent years. The RAS (rat sarcoma) pathway is among the most frequently mutated pathways in human cancer. Whereas targeting mutant Kirsten RAS (KRAS) remains difficult, mutant B rapidly accelerated fibrosarcoma (BRAF) kinase is an established drug target in cancer. Now data show that neuroblastoma RAS (NRAS) and even Harvey RAS (HRAS) mutations could be predictive markers for treatment with mitogen-activated protein kinase (MEK) inhibitors. This review discusses recent preclinical and clinical studies of MEK inhibitors in BRAF and RAS mutant cancer. PMID:26691679

  16. Extraction of 3D information from sonar image sequences.

    PubMed

    Trucco, A; Curletto, S

    2003-01-01

    This paper describes a set of methods that make it possible to estimate the position of a feature inside a three-dimensional (3D) space by starting from a sequence of two-dimensional (2D) acoustic images of the seafloor acquired with a sonar system. Typical sonar imaging systems are able to generate just 2D images, and the acquisition of 3D information involves sharp increases in complexity and costs. The front-scan sonar proposed in this paper is a new equipment devoted to acquiring a 2D image of the seafloor to sail over, and allows one to collect a sequence of images showing a specific feature during the approach of the ship. This fact seems to make it possible to recover the 3D position of a feature by comparing the feature positions along the sequence of images acquired from different (known) ship positions. This opportunity is investigated in the paper, where it is shown that encouraging results have been obtained by a processing chain composed of some blocks devoted to low-level processing, feature extraction and analysis, a Kalman filter for robust feature tracking, and some ad hoc equations for depth estimation and averaging. A statistical error analysis demonstrated the great potential of the proposed system also if some inaccuracies affect the sonar measures and the knowledge of the ship position. This was also confirmed by several tests performed on both simulated and real sequences, obtaining satisfactory results on both the feature tracking and, above all, the estimation of the 3D position.

  17. Novel sonar signal processing tool using Shannon entropy

    SciTech Connect

    Quazi, A.H.

    1996-06-01

    Traditionally, conventional signal processing extracts information from sonar signals using amplitude, signal energy or frequency domain quantities obtained using spectral analysis techniques. The object is to investigate an alternate approach which is entirely different than that of traditional signal processing. This alternate approach is to utilize the Shannon entropy as a tool for the processing of sonar signals with emphasis on detection, classification, and localization leading to superior sonar system performance. Traditionally, sonar signals are processed coherently, semi-coherently, and incoherently, depending upon the a priori knowledge of the signals and noise. Here, the detection, classification, and localization technique will be based on the concept of the entropy of the random process. Under a constant energy constraint, the entropy of a received process bearing finite number of sample points is maximum when hypothesis H{sub 0} (that the received process consists of noise alone) is true and decreases when correlated signal is present (H{sub 1}). Therefore, the strategy used for detection is: (I) Calculate the entropy of the received data; then, (II) compare the entropy with the maximum value; and, finally, (III) make decision: H{sub 1} is assumed if the difference is large compared to pre-assigned threshold and H{sub 0} is otherwise assumed. The test statistics will be different between entropies under H{sub 0} and H{sub 1}. Here, we shall show the simulated results for detecting stationary and non-stationary signals in noise, and results on detection of defects in a Plexiglas bar using an ultrasonic experiment conducted by Hughes. {copyright} {ital 1996 American Institute of Physics.}

  18. Optimized passive sonar placement to allow improved interdiction

    NASA Astrophysics Data System (ADS)

    Johnson, Bruce A.; Matthews, Cameron

    2016-05-01

    footprint. The resulting coverage optimizes the likelihood of encounter given an arbitrary sensor profile and threat from a free field statistical model approach. The free field statistical model is particularly applicable to worst case scenario modeling in open ocean operational profiles where targets to do not follow a particular pattern in any of the modeled dimensions. We present an algorithmic testbed which shows how to achieve approximately optimal solutions to the AGP for a network of underwater sensor nodes with or without effector systems for engagement while operating under changing environmental circumstances. The means by which we accomplish this goal are three-fold: 1) Develop a 3D model for the sonar signal propagating through the underwater environment 2) Add rigorous physics-based modeling of environmental events which can affect sensor information acquisition 3) Provide innovative solutions to the AGP which account for the environmental circumstances affecting sensor performance.

  19. Assessment of Marine Mammal Impact Zones for Use of Military Sonar in the Baltic Sea.

    PubMed

    Andersson, Mathias H; Johansson, Torbjörn

    2016-01-01

    Military sonars are known to have caused cetaceans to strand. Navies in shallow seas use different frequencies and sonar pulses, commonly frequencies between 25 and 100 kHz, compared with most studied NATO sonar systems that have been evaluated for their environmental impact. These frequencies match the frequencies of best hearing in the harbor porpoises and seals resident in the Baltic Sea. This study uses published temporary and permanent threshold shifts, measured behavioral response thresholds, technical specifications of a sonar system, and environmental parameters affecting sound propagation common for the Baltic Sea to estimate the impact zones for harbor porpoises and seals.

  20. Assessment of Marine Mammal Impact Zones for Use of Military Sonar in the Baltic Sea.

    PubMed

    Andersson, Mathias H; Johansson, Torbjörn

    2016-01-01

    Military sonars are known to have caused cetaceans to strand. Navies in shallow seas use different frequencies and sonar pulses, commonly frequencies between 25 and 100 kHz, compared with most studied NATO sonar systems that have been evaluated for their environmental impact. These frequencies match the frequencies of best hearing in the harbor porpoises and seals resident in the Baltic Sea. This study uses published temporary and permanent threshold shifts, measured behavioral response thresholds, technical specifications of a sonar system, and environmental parameters affecting sound propagation common for the Baltic Sea to estimate the impact zones for harbor porpoises and seals. PMID:26610942

  1. Extracellularly activated nanocarriers: A new paradigm of tumor targeted drug delivery

    PubMed Central

    Gullotti, Emily; Yeo, Yoon

    2009-01-01

    One of the main goals of nanomedicine is to develop a nanocarrier that can selectively deliver anti-cancer drugs to the targeted tumors. Extensive efforts have resulted in several tumor-targeted nanocarriers, some of which are approved for clinical use. Most nanocarriers achieve tumor-selective accumulation through the enhanced permeability and retention effect. Targeting molecules such as antibodies, peptides, ligands, or nucleic acids attached to the nanocarriers further enhance their recognition and internalization by the target tissues. While both the stealth and targeting features are important for effective and selective drug delivery to the tumors, achieving both features simultaneously is often found to be difficult. Some of the recent targeting strategies have the potential to overcome this challenge. These strategies utilize the unique extracellular environment of tumors to change the long-circulating nanocarriers to release the drug or interact with cells in a tumor-specific manner. This review discusses the new targeting strategies with recent examples, which utilize the environmental stimuli to activate the nanocarriers. Traditional strategies for tumor-targeted nanocarriers are briefly discussed with an emphasis on their achievements and challenges. PMID:19366234

  2. Right temporoparietal junction activation by a salient contextual cue facilitates target discrimination.

    PubMed

    Geng, Joy J; Mangun, George R

    2011-01-01

    The right temporoparietal junction (R TPJ) is involved in stimulus-driven attentional control in response to the appearance of an unexpected target or a distractor that shares features with a task-relevant target. An unresolved question is whether these responses in R TPJ are due simply to the presence of a stimulus that is a potential target, or instead responds to any task-relevant information. Here, we addressed this issue by testing the sensitivity of R TPJ to a perceptually salient, non-target stimulus - a contextual cue. Although known to be a non-target, the contextual cue carried probabilistic information regarding the presence of a target in the opposite visual field. The contextual cue was therefore always of potential behavioral relevance, but only sometimes paired with a target. The appearance of the contextual cue alone increased activation in R TPJ, but more so when it appeared with a target. There was also greater connectivity between R TPJ and a network of attentional control and decision areas when the contextual cue was present. These results demonstrate that R TPJ is involved in the stimulus-driven representation of task-relevant information that can be used to engage an appropriate behavioral response.

  3. Blue whales respond to simulated mid-frequency military sonar.

    PubMed

    Goldbogen, Jeremy A; Southall, Brandon L; DeRuiter, Stacy L; Calambokidis, John; Friedlaender, Ari S; Hazen, Elliott L; Falcone, Erin A; Schorr, Gregory S; Douglas, Annie; Moretti, David J; Kyburg, Chris; McKenna, Megan F; Tyack, Peter L

    2013-08-22

    Mid-frequency military (1-10 kHz) sonars have been associated with lethal mass strandings of deep-diving toothed whales, but the effects on endangered baleen whale species are virtually unknown. Here, we used controlled exposure experiments with simulated military sonar and other mid-frequency sounds to measure behavioural responses of tagged blue whales (Balaenoptera musculus) in feeding areas within the Southern California Bight. Despite using source levels orders of magnitude below some operational military systems, our results demonstrate that mid-frequency sound can significantly affect blue whale behaviour, especially during deep feeding modes. When a response occurred, behavioural changes varied widely from cessation of deep feeding to increased swimming speed and directed travel away from the sound source. The variability of these behavioural responses was largely influenced by a complex interaction of behavioural state, the type of mid-frequency sound and received sound level. Sonar-induced disruption of feeding and displacement from high-quality prey patches could have significant and previously undocumented impacts on baleen whale foraging ecology, individual fitness and population health.

  4. Estimation and simulation of multi-beam sonar noise.

    PubMed

    Holmin, Arne Johannes; Korneliussen, Rolf J; Tjøstheim, Dag

    2016-02-01

    Methods for the estimation and modeling of noise present in multi-beam sonar data, including the magnitude, probability distribution, and spatial correlation of the noise, are developed. The methods consider individual acoustic samples and facilitate compensation of highly localized noise as well as subtraction of noise estimates averaged over time. The modeled noise is included in an existing multi-beam sonar simulation model [Holmin, Handegard, Korneliussen, and Tjøstheim, J. Acoust. Soc. Am. 132, 3720-3734 (2012)], resulting in an improved model that can be used to strengthen interpretation of data collected in situ at any signal to noise ratio. Two experiments, from the former study in which multi-beam sonar data of herring schools were simulated, are repeated with inclusion of noise. These experiments demonstrate (1) the potentially large effect of changes in fish orientation on the backscatter from a school, and (2) the estimation of behavioral characteristics such as the polarization and packing density of fish schools. The latter is achieved by comparing real data with simulated data for different polarizations and packing densities. PMID:26936566

  5. Blue whales respond to simulated mid-frequency military sonar.

    PubMed

    Goldbogen, Jeremy A; Southall, Brandon L; DeRuiter, Stacy L; Calambokidis, John; Friedlaender, Ari S; Hazen, Elliott L; Falcone, Erin A; Schorr, Gregory S; Douglas, Annie; Moretti, David J; Kyburg, Chris; McKenna, Megan F; Tyack, Peter L

    2013-08-22

    Mid-frequency military (1-10 kHz) sonars have been associated with lethal mass strandings of deep-diving toothed whales, but the effects on endangered baleen whale species are virtually unknown. Here, we used controlled exposure experiments with simulated military sonar and other mid-frequency sounds to measure behavioural responses of tagged blue whales (Balaenoptera musculus) in feeding areas within the Southern California Bight. Despite using source levels orders of magnitude below some operational military systems, our results demonstrate that mid-frequency sound can significantly affect blue whale behaviour, especially during deep feeding modes. When a response occurred, behavioural changes varied widely from cessation of deep feeding to increased swimming speed and directed travel away from the sound source. The variability of these behavioural responses was largely influenced by a complex interaction of behavioural state, the type of mid-frequency sound and received sound level. Sonar-induced disruption of feeding and displacement from high-quality prey patches could have significant and previously undocumented impacts on baleen whale foraging ecology, individual fitness and population health. PMID:23825206

  6. Blue whales respond to simulated mid-frequency military sonar

    PubMed Central

    Goldbogen, Jeremy A.; Southall, Brandon L.; DeRuiter, Stacy L.; Calambokidis, John; Friedlaender, Ari S.; Hazen, Elliott L.; Falcone, Erin A.; Schorr, Gregory S.; Douglas, Annie; Moretti, David J.; Kyburg, Chris; McKenna, Megan F.; Tyack, Peter L.

    2013-01-01

    Mid-frequency military (1–10 kHz) sonars have been associated with lethal mass strandings of deep-diving toothed whales, but the effects on endangered baleen whale species are virtually unknown. Here, we used controlled exposure experiments with simulated military sonar and other mid-frequency sounds to measure behavioural responses of tagged blue whales (Balaenoptera musculus) in feeding areas within the Southern California Bight. Despite using source levels orders of magnitude below some operational military systems, our results demonstrate that mid-frequency sound can significantly affect blue whale behaviour, especially during deep feeding modes. When a response occurred, behavioural changes varied widely from cessation of deep feeding to increased swimming speed and directed travel away from the sound source. The variability of these behavioural responses was largely influenced by a complex interaction of behavioural state, the type of mid-frequency sound and received sound level. Sonar-induced disruption of feeding and displacement from high-quality prey patches could have significant and previously undocumented impacts on baleen whale foraging ecology, individual fitness and population health. PMID:23825206

  7. Seafloor Characterisation and Imaging Using Multibeam Sonar Data

    NASA Astrophysics Data System (ADS)

    Łubniewski, Zbigniew; Bruniecki, Krzysztof

    The approach to seafloor characterisation and imaging is presented. It relies on the combined, concurrent use of several techniques of multibeam sonar data processing. The first one is based on constructing the grey-level sonar images of seabed using the backscattering strength calculated for the echoes received in the consecutive beams. Then, the set of parameters describing the local region of sonar image is calculated. The second technique utilises the 3D model of the seabed surface, which is constructed as a set of (x, y, z) points using the detected bottom range for each beam in the multibeam system seafloor imaging procedure. For the local region of seabed surface, the descriptors like rms height and autocorrelation slope are calculated. The third technique assumes the use of a set of parameters of the multibeam echo envelope. Then, for selected parameters, the characteristic features quantitatively describing their dependence on seafloor incident angle, like slope, or range, are calculated. Finally, the features obtained by these three techniques are combined together. The proposed method has been tested using multibeam data records acquired from several bottom types in the Gulf of Gdańsk region. The obtained preliminary results show that application of the proposed combined approach improves the classification performance in comparison with those of using only the one scheme of seafloor multibeam data processing.

  8. Application of acoustic reflection tomography to sonar imaging.

    PubMed

    Ferguson, Brian G; Wyber, Ron J

    2005-05-01

    Computer-aided tomography is a technique for providing a two-dimensional cross-sectional view of a three-dimensional object through the digital processing of many one-dimensional views (or projections) taken at different look directions. In acoustic reflection tomography, insonifying the object and then recording the backscattered signal provides the projection information for a given look direction (or aspect angle). Processing the projection information for all possible aspect angles enables an image to be reconstructed that represents the two-dimensional spatial distribution of the object's acoustic reflectivity function when projected on the imaging plane. The shape of an idealized object, which is an elliptical cylinder, is reconstructed by applying standard backprojection, Radon transform inversion (using both convolution and filtered backprojections), and direct Fourier inversion to simulated projection data. The relative merits of the various reconstruction algorithms are assessed and the resulting shape estimates compared. For bandpass sonar data, however, the wave number components of the acoustic reflectivity function that are outside the passband are absent. This leads to the consideration of image reconstruction for bandpass data. Tomographic image reconstruction is applied to real data collected with an ultra-wideband sonar transducer to form high-resolution acoustic images of various underwater objects when the sonar and object are widely separated.

  9. A miniature high resolution 3-D imaging sonar.

    PubMed

    Josserand, Tim; Wolley, Jason

    2011-04-01

    This paper discusses the design and development of a miniature, high resolution 3-D imaging sonar. The design utilizes frequency steered phased arrays (FSPA) technology. FSPAs present a small, low-power solution to the problem of underwater imaging sonars. The technology provides a method to build sonars with a large number of beams without the proportional power, circuitry and processing complexity. The design differs from previous methods in that the array elements are manufactured from a monolithic material. With this technique the arrays are flat and considerably smaller element dimensions are achievable which allows for higher frequency ranges and smaller array sizes. In the current frequency range, the demonstrated array has ultra high image resolution (1″ range×1° azimuth×1° elevation) and small size (<3″×3″). The design of the FSPA utilizes the phasing-induced frequency-dependent directionality of a linear phased array to produce multiple beams in a forward sector. The FSPA requires only two hardware channels per array and can be arranged in single and multiple array configurations that deliver wide sector 2-D images. 3-D images can be obtained by scanning the array in a direction perpendicular to the 2-D image field and applying suitable image processing to the multiple scanned 2-D images. This paper introduces the 3-D FSPA concept, theory and design methodology. Finally, results from a prototype array are presented and discussed.

  10. Effects of environmental uncertainties on sonar detection performance prediction.

    PubMed

    Sha, Liewei; Nolte, Loren W

    2005-04-01

    The development of effective passive sonar systems depends upon the ability to accurately predict the performance of sonar detection algorithms in realistic ocean environments. Such environments are typically characterized by a high degree of uncertainty, thus limiting the usefulness of performance prediction approaches that assume a deterministic environment. Here we derive closed-form receiver operating characteristic (ROC) expressions for an optimal Bayesian detector and for several typical suboptimal detectors, based on a statistical model of environmental uncertainty. Various scenarios extended from an NRL benchmark shallow-water model were used to check the analytical ROC expressions and to illustrate the effect of environmental uncertainty on detection performance. The results showed that (1) optimal detection performance in an uncertain environment in diffuse noise depends primarily on the signal-to-noise ratio at the receivers and the rank of the signal matrix, where the rank is an effective representation of the scale of environmental uncertainty; (2) the ROC expression for the optimal Bayesian detector provides a more realistic performance upper bound than that obtained from conventional sonar equations that do not incorporate environmental uncertainty; and (3) detection performance predictions can be performed much faster than with commonly used numerical methods such as Monte Carlo performance evaluations.

  11. Estimation and simulation of multi-beam sonar noise.

    PubMed

    Holmin, Arne Johannes; Korneliussen, Rolf J; Tjøstheim, Dag

    2016-02-01

    Methods for the estimation and modeling of noise present in multi-beam sonar data, including the magnitude, probability distribution, and spatial correlation of the noise, are developed. The methods consider individual acoustic samples and facilitate compensation of highly localized noise as well as subtraction of noise estimates averaged over time. The modeled noise is included in an existing multi-beam sonar simulation model [Holmin, Handegard, Korneliussen, and Tjøstheim, J. Acoust. Soc. Am. 132, 3720-3734 (2012)], resulting in an improved model that can be used to strengthen interpretation of data collected in situ at any signal to noise ratio. Two experiments, from the former study in which multi-beam sonar data of herring schools were simulated, are repeated with inclusion of noise. These experiments demonstrate (1) the potentially large effect of changes in fish orientation on the backscatter from a school, and (2) the estimation of behavioral characteristics such as the polarization and packing density of fish schools. The latter is achieved by comparing real data with simulated data for different polarizations and packing densities.

  12. Qualitative and quantitative processing of side-scan sonar data

    SciTech Connect

    Dwan, F.S.; Anderson, A.L.; Hilde, T.W.C. )

    1990-06-01

    Modern side-scan sonar systems allow vast areas of seafloor to be rapidly imaged and quantitatively mapped in detail. The application of remote sensing image processing techniques can be used to correct for various distortions inherent in raw sonography. Corrections are possible for water column, slant-range, aspect ratio, speckle and striping noise, multiple returns, power drop-off, and for georeferencing. The final products reveal seafloor features and patterns that are geometrically correct, georeferenced, and have improved signal/noise ratio. These products can be merged with other georeferenced data bases for further database management and information extraction. In order to compare data collected by different systems from a common area and to ground truth measurements and geoacoustic models, quantitative correction must be made for calibrated sonar system and bathymetry effects. Such data inversion must account for system source level, beam pattern, time-varying gain, processing gain, transmission loss, absorption, insonified area, and grazing angle effects. Seafloor classification can then be performed on the calculated back-scattering strength using Lambert's Law and regression analysis. Examples are given using both approaches: image analysis and inversion of data based on the sonar equation.

  13. Nonimmunoglobulin target loci of activation-induced cytidine deaminase (AID) share unique features with immunoglobulin genes

    PubMed Central

    Kato, Lucia; Begum, Nasim A.; Burroughs, A. Maxwell; Doi, Tomomitsu; Kawai, Jun; Daub, Carsten O.; Kawaguchi, Takahisa; Matsuda, Fumihiko; Hayashizaki, Yoshihide; Honjo, Tasuku

    2012-01-01

    Activation-induced cytidine deaminase (AID) is required for both somatic hypermutation and class-switch recombination in activated B cells. AID is also known to target nonimmunoglobulin genes and introduce mutations or chromosomal translocations, eventually causing tumors. To identify as-yet-unknown AID targets, we screened early AID-induced DNA breaks by using two independent genome-wide approaches. Along with known AID targets, this screen identified a set of unique genes (SNHG3, MALAT1, BCL7A, and CUX1) and confirmed that these loci accumulated mutations as frequently as Ig locus after AID activation. Moreover, these genes share three important characteristics with the Ig gene: translocations in tumors, repetitive sequences, and the epigenetic modification of chromatin by H3K4 trimethylation in the vicinity of cleavage sites. PMID:22308462

  14. Centrosomal targeting of tyrosine kinase activity does not enhance oncogenicity in chronic myeloproliferative disorders.

    PubMed

    Bochtler, T; Kirsch, M; Maier, B; Bachmann, J; Klingmüller, U; Anderhub, S; Ho, A D; Krämer, A

    2012-04-01

    Constitutive tyrosine kinase activation by reciprocal chromosomal translocation is a common pathogenetic mechanism in chronic myeloproliferative disorders. Since centrosomal proteins have been recurrently identified as translocation partners of tyrosine kinases FGFR1, JAK2, PDGFRα and PDGFRβ in these diseases, a role for the centrosome in oncogenic transformation has been hypothesized. In this study, we addressed the functional role of centrosomally targeted tyrosine kinase activity. First, centrosomal localization was not routinely found for all chimeric fusion proteins tested. Second, targeting of tyrosine kinases to the centrosome by creating artificial chimeric fusion kinases with the centrosomal targeting domain of AKAP450 failed to enhance the oncogenic transforming potential in both Ba/F3 and U2OS cells, although phospho-tyrosine-mediated signal transduction pathways were initiated at the centrosome. We conclude that the centrosomal localization of constitutively activated tyrosine kinases does not contribute to disease pathogenesis in chronic myeloproliferative disorders. PMID:22015771

  15. Nonimmunoglobulin target loci of activation-induced cytidine deaminase (AID) share unique features with immunoglobulin genes.

    PubMed

    Kato, Lucia; Begum, Nasim A; Burroughs, A Maxwell; Doi, Tomomitsu; Kawai, Jun; Daub, Carsten O; Kawaguchi, Takahisa; Matsuda, Fumihiko; Hayashizaki, Yoshihide; Honjo, Tasuku

    2012-02-14

    Activation-induced cytidine deaminase (AID) is required for both somatic hypermutation and class-switch recombination in activated B cells. AID is also known to target nonimmunoglobulin genes and introduce mutations or chromosomal translocations, eventually causing tumors. To identify as-yet-unknown AID targets, we screened early AID-induced DNA breaks by using two independent genome-wide approaches. Along with known AID targets, this screen identified a set of unique genes (SNHG3, MALAT1, BCL7A, and CUX1) and confirmed that these loci accumulated mutations as frequently as Ig locus after AID activation. Moreover, these genes share three important characteristics with the Ig gene: translocations in tumors, repetitive sequences, and the epigenetic modification of chromatin by H3K4 trimethylation in the vicinity of cleavage sites.

  16. Pseudo multisensor fusion schemes for mine detection in side-scan sonar images

    NASA Astrophysics Data System (ADS)

    Guo, Weiming; Szymczak, William G.

    1999-08-01

    Most of the fusion algorithms reported operate in a multi- sensor environment. In this paper, we investigate a novel fusion strategy that operates on images obtained from a single sensor. There exists a variety of methods for mien detection in sonar or laser line scan images, but single method can be considered as the best under all circumstances. Targets missed by certain algorithms might be detected by others. It can be shown that, by applying various algorithms to the same mine detection task and fusing the decisions together, one can obtain a superior detector. However, in certain difficult applications, the weaknesses of various classifiers reinforce each other. This may be due to the fact that when most classifiers are developed, the primary goal is always to achieve the highest detection over false alarm ratio. Thus, certain type of targets might be neglected by most of the detection algorithms in favor of many other targets that can be easily detected. This scenario posts challenges to decision level fusion algorithm developers, who have to develop several complementary detection algorithms. The novel fusion strategy we described in this paper applies different image enhancement algorithms to the same image before the classification stage. Since image enhancement algorithms are more diversified than detection algorithms, they tend to highlight complementary features of the mien targets in the same data set, thus producing a pseudo multi-sensor environment. These detection decisions on multiple looks of the same image are then fused together to create a superior detection scheme.

  17. Activity and radiation protection studies for the W-Ta target of CSNS.

    PubMed

    Yu, Q Z; Liang, T J; Yin, W

    2009-09-01

    The Chinese government initiated a conceptual design for the project of China Spallation Neutron Source (CSNS), which consists of an H-linear accelerator, a rapid cycling synchrotron accelerating the beam to 1.6 GeV, a target station converting proton beam into lower energy (<1 eV) neutron beam optimised to instruments for neutron scattering applications. The facility operates at 25-Hz repetition rate with an initial beam power of 100 kW. In the target station, the target-moderator-reflector (TMR) components are exposed to the intensive fluxes of high-energy hadrons and become highly radioactive as a result of long-time irradiation. In this paper, the activity of the TMR components are calculated using the Monte Carlo code system LAHET&MCNP4C&CINDER'90. Comparisons of some results with that simulated by FLUKA code are also performed. Detailed analyses of the radionuclides and their characters in the tantalum clad tungsten target (W-Ta target) are important for the radiation protection of the CSNS target station. The shielding design of the service cell for the decay gamma ray induced from the W-Ta target and its vessel shows that the ambient dose rate decreases exponentially with increasing heavy concrete thickness. And 80 cm thickness of heavy concrete for each side of the service cell can satisfy the safety requirement. PMID:19770213

  18. Remote Bridge Deflection Measurement Using an Advanced Video Deflectometer and Actively Illuminated LED Targets.

    PubMed

    Tian, Long; Pan, Bing

    2016-01-01

    An advanced video deflectometer using actively illuminated LED targets is proposed for remote, real-time measurement of bridge deflection. The system configuration, fundamental principles, and measuring procedures of the video deflectometer are first described. To address the challenge of remote and accurate deflection measurement of large engineering structures without being affected by ambient light, the novel idea of active imaging, which combines high-brightness monochromatic LED targets with coupled bandpass filter imaging, is introduced. Then, to examine the measurement accuracy of the proposed advanced video deflectometer in outdoor environments, vertical motions of an LED target with precisely-controlled translations were measured and compared with prescribed values. Finally, by tracking six LED targets mounted on the bridge, the developed video deflectometer was applied for field, remote, and multipoint deflection measurement of the Wuhan Yangtze River Bridge, one of the most prestigious and most publicized constructions in China, during its routine safety evaluation tests. Since the proposed video deflectometer using actively illuminated LED targets offers prominent merits of remote, contactless, real-time, and multipoint deflection measurement with strong robustness against ambient light changes, it has great potential in the routine safety evaluation of various bridges and other large-scale engineering structures. PMID:27563901

  19. Active target studies of the αp-process at CRIB

    NASA Astrophysics Data System (ADS)

    Kahl, D.; Hashimoto, T.; Duy, N. N.; Kubono, S.; Yamaguchi, H.; Binh, D. N.; Chen, A. A.; Cherubini, S.; Hayakawa, S.; He, J. J.; Ishiyama, H.; Iwasa, N.; Khiem, L. H.; Kwon, Y. K.; Michimasa, S.; Nakao, T.; Ota, S.; Teranishi, T.; Tokieda, H.; Wakabayashi, Y.; Yamada, T.; Zhang, L. Y.

    2014-05-01

    The αp-process is a sequence of (α, p)(p, γ) reactions important to the nuclear trajectory to higher masses in type I X-ray bursts. Specifically, the αp-process is schematically pure helium-burning, and thus unlike pure hydrogen-burning processes, does not require slow β+ decays. Explosive helium burning is responsible for the observed short rise-times of X-ray bursts but ultimately gives way to the rp-process as the Coulomb barrier increases. Because the stellar reaction rates of these (α, p) reactions are poorly known over the relevant astrophysical energies, we performed systematic studies of the 18Ne(α,p), 22Mg(α,p) and 30S(α,p) reactions at the Center for Nuclear Study (CNS) low-energy radioactive ion beam separator, called CRIB. We produce the radioactive beams in-flight and scan the center-of-mass energy down into the Gamow Window using a thick target in inverse kinematics. The helium target gas also serves as part of the detector system, an active target, which was newly designed for these measurements. The active target, which uses gas electron multiplier (GEM) foils, allows for higher beam injection rates than previous multi-sampling and tracking proportional counters (MSTPC). We present a summary of our recent results from these active target experiments at CRIB.

  20. Remote Bridge Deflection Measurement Using an Advanced Video Deflectometer and Actively Illuminated LED Targets

    PubMed Central

    Tian, Long; Pan, Bing

    2016-01-01

    An advanced video deflectometer using actively illuminated LED targets is proposed for remote, real-time measurement of bridge deflection. The system configuration, fundamental principles, and measuring procedures of the video deflectometer are first described. To address the challenge of remote and accurate deflection measurement of large engineering structures without being affected by ambient light, the novel idea of active imaging, which combines high-brightness monochromatic LED targets with coupled bandpass filter imaging, is introduced. Then, to examine the measurement accuracy of the proposed advanced video deflectometer in outdoor environments, vertical motions of an LED target with precisely-controlled translations were measured and compared with prescribed values. Finally, by tracking six LED targets mounted on the bridge, the developed video deflectometer was applied for field, remote, and multipoint deflection measurement of the Wuhan Yangtze River Bridge, one of the most prestigious and most publicized constructions in China, during its routine safety evaluation tests. Since the proposed video deflectometer using actively illuminated LED targets offers prominent merits of remote, contactless, real-time, and multipoint deflection measurement with strong robustness against ambient light changes, it has great potential in the routine safety evaluation of various bridges and other large-scale engineering structures. PMID:27563901

  1. Active target studies of the αp-process at CRIB

    SciTech Connect

    Kahl, D.; Yamaguchi, H.; Michimasa, S.; Nakao, T.; Ota, S.; Tokieda, H.; Hashimoto, T.; Duy, N. N.; Khiem, L. H.; Kubono, S.; Binh, D. N.; Chen, A. A.; Cherubini, S.; Hayakawa, S.; He, J. J.; Zhang, L. Y.; Ishiyama, H.; Iwasa, N.; Yamada, T.; Kwon, Y. K.; and others

    2014-05-02

    The αp-process is a sequence of (α, p)(p, γ) reactions important to the nuclear trajectory to higher masses in type I X-ray bursts. Specifically, the αp-process is schematically pure helium-burning, and thus unlike pure hydrogen-burning processes, does not require slow β{sup +} decays. Explosive helium burning is responsible for the observed short rise-times of X-ray bursts but ultimately gives way to the rp-process as the Coulomb barrier increases. Because the stellar reaction rates of these (α, p) reactions are poorly known over the relevant astrophysical energies, we performed systematic studies of the {sup 18}Ne(α,p), {sup 22}Mg(α,p) and {sup 30}S(α,p) reactions at the Center for Nuclear Study (CNS) low-energy radioactive ion beam separator, called CRIB. We produce the radioactive beams in-flight and scan the center-of-mass energy down into the Gamow Window using a thick target in inverse kinematics. The helium target gas also serves as part of the detector system, an active target, which was newly designed for these measurements. The active target, which uses gas electron multiplier (GEM) foils, allows for higher beam injection rates than previous multi-sampling and tracking proportional counters (MSTPC). We present a summary of our recent results from these active target experiments at CRIB.

  2. Direct activation of the apoptosis machinery as a mechanism to target cancer cells.

    PubMed

    Nguyen, Jack T; Wells, James A

    2003-06-24

    Apoptosis plays a pivotal role in the cytotoxic activity of most chemotherapeutic drugs, and defects in this pathway provide a basis for drug resistance in many cancers. Thus the ability to restore apoptosis by using small molecules could have important therapeutic implications. Using a cell-free assay to simultaneously target multiple components of the apoptosis pathway, we identified a class of compounds that activate caspases in a cytochrome c-dependent manner and induce apoptosis in whole cells. By reconstituting the apoptosis pathway with purified proteins, we determined that these compounds promote the protein-protein association of Apaf-1 into the functional apoptosome. These compounds exert cytostatic and cytotoxic effects on a variety of cancer cell lines while having little or no activity against the normal cell lines tested. These findings suggest that direct activation of the basic apoptosis machinery may be a viable mechanism to selectively target cancer.

  3. Fimbrolide Natural Products Disrupt Bioluminescence of Vibrio By Targeting Autoinducer Biosynthesis and Luciferase Activity.

    PubMed

    Zhao, Weining; Lorenz, Nicola; Jung, Kirsten; Sieber, Stephan A

    2016-01-18

    Vibrio is a model organism for the study of quorum sensing (QS) signaling and is used to identify QS-interfering drugs. Naturally occurring fimbrolides are important tool compounds known to affect QS in various organisms; however, their cellular targets have so far remained elusive. Here we identify the irreversible fimbrolide targets in the proteome of living V. harveyi and V. campbellii via quantitative mass spectrometry utilizing customized probes. Among the major hits are two protein targets with essential roles in Vibrio QS and bioluminescence. LuxS, responsible for autoinducer 2 biosynthesis, and LuxE, a subunit of the luciferase complex, were both covalently modified at their active-site cysteines leading to inhibition of activity. The identification of LuxE unifies previous reports suggesting inhibition of bioluminescence downstream of the signaling cascade and thus contributes to a better mechanistic understanding of these QS tool compounds.

  4. Light-controlled active release of photocaged ciprofloxacin for lipopolysaccharide-targeted drug delivery using dendrimer conjugates.

    PubMed

    Wong, Pamela T; Tang, Shengzhuang; Mukherjee, Jhindan; Tang, Kenny; Gam, Kristina; Isham, Danielle; Murat, Claire; Sun, Rachel; Baker, James R; Choi, Seok Ki

    2016-08-16

    We report an active delivery mechanism targeted specifically to Gram(-) bacteria based on the photochemical release of photocaged ciprofloxacin carried by a cell wall-targeted dendrimer nanoconjugate. PMID:27476878

  5. Radiation inactivation analysis of influenza virus reveals different target sizes for fusion, leakage, and neuraminidase activities

    SciTech Connect

    Gibson, S.; Jung, C.Y.; Takahashi, M.; Lenard, J.

    1986-10-07

    The size of the functional units responsible for several activities carried out by the influenza virus envelope glycoproteins was determined by radiation inactivation analysis. Neuraminidase activity, which resides in the glycoprotein NA, was inactivated exponentially with an increasing radiation dose, yielding a target size of 94 +/- 5 kilodaltons (kDa), in reasonable agreement with that of the disulfide-bonded dimer (120 kDa). All the other activities studied are properties of the HA glycoprotein and were normalized to the known molecular weight of the neuraminidase dimer. Virus-induced fusion activity was measured by two phospholipid dilution assays: relief of energy transfer between N-(7-nitro-2,1,3-benzoxadiazol-4-yl)dipalmitoyl-L-alpha- phosphatidylethanolamine (N-NBD-PE) and N-(lissamine rhodamine B sulfonyl)-dioleoyl-L-alpha-phosphatidylethanolamine (N-Rh-PE) in target liposomes and relief of self-quenching of N-Rh-PE in target liposomes. Radiation inactivation of fusion activity proceeded exponentially with radiation dose, yielding normalized target sizes of 68 +/- 6 kDa by assay i and 70 +/- 4 kDa by assay ii. These values are close to the molecular weight of a single disulfide-bonded (HA1 + HA2) unit (75 kDa), the monomer of the HA trimer. A single monomer is thus inactivated by each radiation event, and each monomer (or some part of it) constitutes a minimal functional unit capable of mediating fusion. Virus-induced leakage of calcein from target liposomes and virus-induced leakage of hemoglobin from erythrocytes (hemolysis) both showed more complex inactivation behavior: a pronounced shoulder was present in both inactivation curves, followed by a steep drop in activity at higher radiation levels.

  6. The research of multi-frame target recognition based on laser active imaging

    NASA Astrophysics Data System (ADS)

    Wang, Can-jin; Sun, Tao; Wang, Tin-feng; Chen, Juan

    2013-09-01

    Laser active imaging is fit to conditions such as no difference in temperature between target and background, pitch-black night, bad visibility. Also it can be used to detect a faint target in long range or small target in deep space, which has advantage of high definition and good contrast. In one word, it is immune to environment. However, due to the affect of long distance, limited laser energy and atmospheric backscatter, it is impossible to illuminate the whole scene at the same time. It means that the target in every single frame is unevenly or partly illuminated, which make the recognition more difficult. At the same time the speckle noise which is common in laser active imaging blurs the images . In this paper we do some research on laser active imaging and propose a new target recognition method based on multi-frame images . Firstly, multi pulses of laser is used to obtain sub-images for different parts of scene. A denoising method combined homomorphic filter with wavelet domain SURE is used to suppress speckle noise. And blind deconvolution is introduced to obtain low-noise and clear sub-images. Then these sub-images are registered and stitched to combine a completely and uniformly illuminated scene image. After that, a new target recognition method based on contour moments is proposed. Firstly, canny operator is used to obtain contours. For each contour, seven invariant Hu moments are calculated to generate the feature vectors. At last the feature vectors are input into double hidden layers BP neural network for classification . Experiments results indicate that the proposed algorithm could achieve a high recognition rate and satisfactory real-time performance for laser active imaging.

  7. A Network-Based Multi-Target Computational Estimation Scheme for Anticoagulant Activities of Compounds

    PubMed Central

    Li, Canghai; Chen, Lirong; Song, Jun; Tang, Yalin; Xu, Xiaojie

    2011-01-01

    Background Traditional virtual screening method pays more attention on predicted binding affinity between drug molecule and target related to a certain disease instead of phenotypic data of drug molecule against disease system, as is often less effective on discovery of the drug which is used to treat many types of complex diseases. Virtual screening against a complex disease by general network estimation has become feasible with the development of network biology and system biology. More effective methods of computational estimation for the whole efficacy of a compound in a complex disease system are needed, given the distinct weightiness of the different target in a biological process and the standpoint that partial inhibition of several targets can be more efficient than the complete inhibition of a single target. Methodology We developed a novel approach by integrating the affinity predictions from multi-target docking studies with biological network efficiency analysis to estimate the anticoagulant activities of compounds. From results of network efficiency calculation for human clotting cascade, factor Xa and thrombin were identified as the two most fragile enzymes, while the catalytic reaction mediated by complex IXa:VIIIa and the formation of the complex VIIIa:IXa were recognized as the two most fragile biological matter in the human clotting cascade system. Furthermore, the method which combined network efficiency with molecular docking scores was applied to estimate the anticoagulant activities of a serial of argatroban intermediates and eight natural products respectively. The better correlation (r = 0.671) between the experimental data and the decrease of the network deficiency suggests that the approach could be a promising computational systems biology tool to aid identification of anticoagulant activities of compounds in drug discovery. Conclusions This article proposes a network-based multi-target computational estimation method for

  8. Targeting human CD27 with an agonist antibody stimulates T-cell activation and antitumor immunity.

    PubMed

    Thomas, Lawrence J; He, Li-Zhen; Marsh, Henry; Keler, Tibor

    2014-01-01

    CD27 is an important co-stimulatory receptor of T cells that can potentially be exploited for immunotherapy. We developed a human IgG1 antibody that targets human CD27, and demonstrated its immunostimulatory and antineoplastic activity in various preclinical models. Currently, the antibody (1F5, CDX-1127) is being tested in patients affected by advanced malignancies. PMID:24605266

  9. The Role of Specificity, Targeted Learning Activities, and Prior Knowledge for the Effects of Relevance Instructions

    ERIC Educational Resources Information Center

    Roelle, Julian; Lehmkuhl, Nina; Beyer, Martin-Uwe; Berthold, Kirsten

    2015-01-01

    In 2 experiments we examined the role of (a) specificity, (b) the type of targeted learning activities, and (c) learners' prior knowledge for the effects of relevance instructions on learning from instructional explanations. In Experiment 1, we recruited novices regarding the topic of atomic structure (N = 80) and found that "specific"…

  10. Developing, Implementing, and Evaluating a Condom Promotion Program Targeting Sexually Active Adolescents.

    ERIC Educational Resources Information Center

    Alstead, Mark; Campsmith, Michael; Halley, Carolyn Swope; Hartfield, Karen; Goldblum, Gary; Wood, Robert W.

    1999-01-01

    Describes the development, implementation, and evaluation of an HIV prevention program promoting condom use among sexually active adolescents. It mobilized target communities to guide program development and implementation; created a mass media campaign to promote correct condom use; and recruited public agencies and organizations to distribute…

  11. Neuronal targeting, internalization, and biological activity of a recombinant atoxic derivative of botulinum neurotoxin A

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Botulinum neurotoxins (BoNT) have the unique capacity to cross epithelial barriers, target neuromuscular junctions, and translocate active metalloprotease component to the cytosol of motor neurons. We have taken advantage of the molecular carriers responsible for this trafficking to create a family ...

  12. Composite Wavelet Filters for Enhanced Automated Target Recognition

    NASA Technical Reports Server (NTRS)

    Chiang, Jeffrey N.; Zhang, Yuhan; Lu, Thomas T.; Chao, Tien-Hsin

    2012-01-01

    Automated Target Recognition (ATR) systems aim to automate target detection, recognition, and tracking. The current project applies a JPL ATR system to low-resolution sonar and camera videos taken from unmanned vehicles. These sonar images are inherently noisy and difficult to interpret, and pictures taken underwater are unreliable due to murkiness and inconsistent lighting. The ATR system breaks target recognition into three stages: 1) Videos of both sonar and camera footage are broken into frames and preprocessed to enhance images and detect Regions of Interest (ROIs). 2) Features are extracted from these ROIs in preparation for classification. 3) ROIs are classified as true or false positives using a standard Neural Network based on the extracted features. Several preprocessing, feature extraction, and training methods are tested and discussed in this paper.

  13. Composite wavelet filters for enhanced automated target recognition

    NASA Astrophysics Data System (ADS)

    Chiang, Jeffrey N.; Zhang, Yuhan; Lu, Thomas T.; Chao, Tien-Hsin

    2012-04-01

    Automated Target Recognition (ATR) systems aim to automate target detection, recognition, and tracking. The current project applies a JPL ATR system to low-resolution sonar and camera videos taken from unmanned vehicles. These sonar images are inherently noisy and difficult to interpret, and pictures taken underwater were unreliable due to murkiness and inconsistent lighting. The ATR system breaks target recognition into three stages: 1) Videos of both sonar and camera footage are broken into frames and preprocessed to enhance images and detect Regions of Interest (ROIs). 2) Features are extracted from these ROIs in preparation for classification. 3) ROIs are classified as true or false positives using a standard Neural Network based on the extracted features. Several preprocessing, feature extraction, and training methods are tested and discussed in this report.

  14. Prosthetic systems for therapeutic optical activation and silencing of genetically-targeted neurons

    PubMed Central

    Bernstein, Jacob G.; Han, Xue; Henninger, Michael A.; Ko, Emily Y.; Qian, Xiaofeng; Franzesi, Giovanni Talei; McConnell, Jackie P.; Stern, Patrick; Desimone, Robert; Boyden, Edward S.

    2008-01-01

    Many neural disorders are associated with aberrant activity in specific cell types or neural projection pathways embedded within the densely-wired, heterogeneous matter of the brain. An ideal therapy would permit correction of activity just in specific target neurons, while leaving other neurons unaltered. Recently our lab revealed that the naturally-occurring light-activated proteins channelrhodopsin-2 (ChR2) and halorhodopsin (Halo/NpHR) can, when genetically expressed in neurons, enable them to be safely, precisely, and reversibly activated and silenced by pulses of blue and yellow light, respectively. We here describe the ability to make specific neurons in the brain light-sensitive, using a viral approach. We also reveal the design and construction of a scalable, fully-implantable optical prosthetic capable of delivering light of appropriate intensity and wavelength to targeted neurons at arbitrary 3-D locations within the brain, enabling activation and silencing of specific neuron types at multiple locations. Finally, we demonstrate control of neural activity in the cortex of the non-human primate, a key step in the translation of such technology for human clinical use. Systems for optical targeting of specific neural circuit elements may enable a new generation of high-precision therapies for brain disorders. PMID:18458792

  15. Aryl azoles with neuroprotective activity--parallel synthesis and attempts at target identification.

    PubMed

    Cocconcelli, Giuseppe; Diodato, Enrica; Caricasole, Andrea; Gaviraghi, Giovanni; Genesio, Eva; Ghiron, Chiara; Magnoni, Letizia; Pecchioli, Elena; Plazzi, Pier Vincenzo; Terstappen, Georg C

    2008-02-15

    A parallel synthesis of aryl azoles with neuroprotective activity is described. All compounds obtained were evaluated in an in vitro assay using a NMDA toxicity paradigm showing a neuroprotective activity between 15% and 40%. The potential biological target of the active compounds was investigated by extensive literature searches based around similar scaffolds with reported neuroprotective activity. The most interesting molecules active in the NMDA toxicity assay (3a and 2g) showed moderate but significant activity in the inhibition of the Site 2 Sodium Channel binding assay at 10 microM. To confirm our hypothesis compounds 3a, c, f and 2g were tested in the Veratridine assay which is one of the excitotoxicity assays of relevance to NaV channels. The compounds tested showed an activity between 40% and 70%. The identification of neuroprotective small molecules and the identification of NaV channels as the potential site of action were the most important goals of this work.

  16. How Mitogen-Activated Protein Kinases Recognize and Phosphorylate Their Targets: A QM/MM Study

    PubMed Central

    Turjanski, Adrian Gustavo; Hummer, Gerhard; Gutkind, J. Silvio

    2009-01-01

    Mitogen-activated protein kinase (MAPK) signaling pathways play an essential role in the transduction of environmental stimuli to the nucleus, thereby regulating a variety of cellular processes, including cell proliferation, differentiation and programmed cell death. The components of the MAPK extracellular activated protein kinase (ERK) cascade represent attractive targets for cancer therapy as their aberrant activation is a frequent event among highly prevalent human cancers. To understand how MAPKs recognize and phosphorylate their targets is key to unravel their function. However, these events are still poorly understood due to the lack of complex structures of MAPKs with their bound targets in the active site. Here, we have modeled the interaction of ERK with a target peptide and analyzed the specificity towards Ser/Thr-Pro motifs. By using a Quantum Mechanics/Molecular Mechanics (QM/MM) approach we propose a mechanism for the phosphoryl transfer catalyzed by ERK that offers new insights into MAPK function. Our results suggest that 1) the proline residue has a role both in specificity and phospho transfer efficiency; 2) the reaction occurs in one step with ERK2 Asp147 acting as the catalytic base; 3) a conserved Lys in the kinase superfamily usually mutated to check kinase activity strongly stabilizes the transition state; and 4) the reaction mechanism is similar with either one or two Mg2+ ions in the active site. Taken together, our results provide a detailed description of the molecular events involved in the phosphorylation reaction catalyzed by MAPK and contributes to the general understanding of kinase activity. PMID:19361221

  17. Complement receptor 2-mediated targeting of complement inhibitors to sites of complement activation.

    PubMed

    Song, Hongbin; He, Chun; Knaak, Christian; Guthridge, Joel M; Holers, V Michael; Tomlinson, Stephen

    2003-06-01

    In a strategy to specifically target complement inhibitors to sites of complement activation and disease, recombinant fusion proteins consisting of a complement inhibitor linked to a C3 binding region of complement receptor (CR) 2 were prepared and characterized. Natural ligands for CR2 are C3 breakdown products deposited at sites of complement activation. Fusion proteins were prepared consisting of a human CR2 fragment linked to either the N terminus or C terminus of soluble forms of the membrane complement inhibitors decay accelerating factor (DAF) or CD59. The targeted complement inhibitors bound to C3-opsonized cells, and all were significantly more effective (up to 20-fold) than corresponding untargeted inhibitors at protecting target cells from complement. CR2 fusion proteins also inhibited CR3-dependent adhesion of U937 cells to C3 opsonized erythrocytes, indicating a second potential anti-inflammatory mechanism of CR2 fusion proteins, since CR3 is involved in endothelial adhesion and diapedesis of leukocytes at inflammatory sites. Finally, the in vivo validity of the targeting strategy was confirmed by the demonstration that CR2-DAF, but not soluble DAF, targets to the kidney in mouse models of lupus nephritis that are associated with renal complement deposition.

  18. Complement receptor 2-mediated targeting of complement inhibitors to sites of complement activation.

    PubMed

    Song, Hongbin; He, Chun; Knaak, Christian; Guthridge, Joel M; Holers, V Michael; Tomlinson, Stephen

    2003-06-01

    In a strategy to specifically target complement inhibitors to sites of complement activation and disease, recombinant fusion proteins consisting of a complement inhibitor linked to a C3 binding region of complement receptor (CR) 2 were prepared and characterized. Natural ligands for CR2 are C3 breakdown products deposited at sites of complement activation. Fusion proteins were prepared consisting of a human CR2 fragment linked to either the N terminus or C terminus of soluble forms of the membrane complement inhibitors decay accelerating factor (DAF) or CD59. The targeted complement inhibitors bound to C3-opsonized cells, and all were significantly more effective (up to 20-fold) than corresponding untargeted inhibitors at protecting target cells from complement. CR2 fusion proteins also inhibited CR3-dependent adhesion of U937 cells to C3 opsonized erythrocytes, indicating a second potential anti-inflammatory mechanism of CR2 fusion proteins, since CR3 is involved in endothelial adhesion and diapedesis of leukocytes at inflammatory sites. Finally, the in vivo validity of the targeting strategy was confirmed by the demonstration that CR2-DAF, but not soluble DAF, targets to the kidney in mouse models of lupus nephritis that are associated with renal complement deposition. PMID:12813023

  19. Diversity of LFPs Activated in Different Target Regions by a Common CA3 Input.

    PubMed

    Martín-Vázquez, Gonzalo; Benito, Nuria; Makarov, Valeri A; Herreras, Oscar; Makarova, Julia

    2016-10-01

    Identifying the pathways contributing to local field potential (LFP) events and oscillations is essential to determine whether synchronous interregional patterns indicate functional connectivity. Here, we studied experimentally and numerically how different target structures receiving input from a common population shape their LFPs. We focused on the bilateral CA3 that sends gamma-paced excitatory packages to the bilateral CA1, the lateral septum, and itself (recurrent input). The CA3-specific contribution was isolated from multisite LFPs in target regions using spatial discrimination techniques. We found strong modulation of LFPs by target-specific features, including the morphology and population arrangement of cells, the timing of CA3 inputs, volume conduction from nearby targets, and co-activated inhibition. Jointly they greatly affect the LFP amplitude, profile, and frequency characteristics. For instance, ipsilateral (Schaffer) LFPs occluded contralateral ones, and septal LFPs arise mostly from remote sources while local contribution from CA3 input was minor. In the CA3 itself, gamma waves have dual origin from local networks: in-phase excitatory and nearly antiphase inhibitory. Also, waves may have different duration and varying phase in different targets. These results indicate that to explore the cellular basis of LFPs and the functional connectivity between structures, besides identifying the origin population/s, target modifiers should be considered.

  20. Cost estimation for the active debris removal of multiple priority targets

    NASA Astrophysics Data System (ADS)

    Braun, Vitali; Wiedemann, Carsten; Schulz, Eugen

    The increasing number of space debris objects, especially in distinct low Earth orbit (LEO) altitudes between 600 and 1000 km, leads to an increase in the potential collision risk between the objects and threatens active satellites in that region. Several recent studies show that active debris removal (ADR) has to be performed in order to prevent a collisional cascading effect, also known as the Kessler syndrome. In order to stabilize the population growth in the critical LEO region, a removal of five prioritized objects per year has been recognized as a significant figure. Various proposals are addressing the technical issues for ADR missions, including the de-orbiting of objects by means of a service satellite using a chemical or an electric propulsion system. The servicer would rendezvous with a preselected target, perform a docking maneuver and then provide a de-orbit burn to transfer the target on a trajectory where it re-enters the Earth’s atmosphere within a given time frame. In this paper the technical aspects are complemented by a cost estimation model, focusing on multi target missions, which are based on a service satellite capable of de-orbiting more than one target within a single mission. The cost model for ADR includes initial development cost, production cost, launch cost and operation cost as well as the modelling of the propulsion system of the servicer. Therefore, different scenarios are defined for chemical and electric propulsion systems as applied to multi target missions, based on a literature review of concepts currently being under discussion. The costs of multi target missions are compared to a scenario where only one target is removed. Also, the results allow to determine an optimum number of objects to be removed per mission and provide numbers which can be used in future studies, e.g. those related to ADR cost and benefit analyses.

  1. Navy sonar and cetaceans: just how much does the gun need to smoke before we act?

    PubMed

    Parsons, E C M; Dolman, Sarah J; Wright, Andrew J; Rose, Naomi A; Burns, W C G

    2008-07-01

    Cetacean mass stranding events associated with naval mid-frequency sonar use have raised considerable conservation concerns. These strandings have mostly involved beaked whales, with common pathologies, including "bubble lesions" similar to decompression sickness symptoms and acoustic traumas. However, other cetacean species have also stranded coincident with naval exercises. Possible mechanisms for the strandings include a behavioral response that causes deep divers to alter their diving behavior, which then results in decompression sickness-like impacts. Current mitigation measures during military exercises are focused on preventing auditory damage (hearing loss), but there are significant flaws with this approach. Behavioral responses, which occur at lower sound levels than those that cause hearing loss, may be more critical. Thus, mitigation measures should be revised. A growing number of international bodies recognize this issue and have urged increasing scrutiny of sound-producing activities, but many national jurisdictions have resisted calls for increased protection.

  2. Morphological image processing for locating minelike objects from side-scan sonar images

    NASA Astrophysics Data System (ADS)

    Swartzman, Gordon L.; Kooiman, William C.

    1999-08-01

    A morphological image-processing algorithm was developed to facilitate the rapid identification of bottom minelike objects in side scan sonar acoustic backscatter images. Because large numbers of images are being processed, the emphasis is on rapid computation. The algorithm achieves computational efficiency by dividing the image into bins of a pre-chosen size and performing a binary opening operation for each bin with a 2 X 2 structuring element on each bin having sufficient pixels within the threshold range. Thresholding can be either above a high backscatter level to highlight bright proud objects or below a low backscatter level to highlight low backscatter shade-like objects. The morphological operating highlights continuous pixels within the threshold range without distortion and eliminates objects smaller than the structuring element. A connected component algorithm was used to locate all identified contiguous pixels and to tabulate their centroids and sizes. The identified objects were then screened as possible targets by checking the proximity of bright and dark objects within some threshold radius and chosen direction of each other. The chosen targets were either graphed or archived. Algorithm performance was evaluated by comparison with other target identification algorithms and was found to be compatible. An advanced interactive mode allows using different structuring elements and different morphological operations for possible improvement of the batch mode algorithm. The algorithm, while potentially effective for target identification, is primarily useful for false target identification. By operating on standard survey images the algorithm can isolate areas of potential false target proliferation. Spatial statistical methods, based on k- nearest neighbor distributions and hierarchical and k-means clustering were used to delineate regions of high false target density within the survey area.

  3. Redesign of MST enzymes to target lyase activity instead promotes mutase and dehydratase activities

    PubMed Central

    Meneely, Kathleen M.; Luo, Qianyi; Lamb, Audrey L.

    2013-01-01

    The isochorismate and salicylate synthases are members of the MST family of enzymes. The isochorismate synthases establish an equilibrium for the conversion chorismate to isochorismate and the reverse reaction. The salicylate synthases convert chorismate to salicylate with an isochorismate intermediate; therefore, the salicylate synthases perform isochorismate synthase and isochorismate-pyruvate lyase activities sequentially. While the active site residues are highly conserved, there are two sites that show trends for lyase-activity and lyase-deficiency. Using steady state kinetics and HPLC progress curves, we tested the “interchange” hypothesis that interconversion of the amino acids at these sites would promote lyase activity in the isochorismate synthases and remove lyase activity from the salicylate synthases. An alternative, “permute” hypothesis, that chorismate-utilizing enzymes are designed to permute the substrate into a variety of products and tampering with the active site may lead to identification of adventitious activities, is tested by more sensitive NMR time course experiments. The latter hypothesis held true. The variant enzymes predominantly catalyzed chorismate mutase-prephenate dehydratase activities, sequentially generating prephenate and phenylpyruvate, augmenting previously debated (mutase) or undocumented (dehydratase) adventitious activities. PMID:24055536

  4. Redesign of MST enzymes to target lyase activity instead promotes mutase and dehydratase activities.

    PubMed

    Meneely, Kathleen M; Luo, Qianyi; Lamb, Audrey L

    2013-11-01

    The isochorismate and salicylate synthases are members of the MST family of enzymes. The isochorismate synthases establish an equilibrium for the conversion chorismate to isochorismate and the reverse reaction. The salicylate synthases convert chorismate to salicylate with an isochorismate intermediate; therefore, the salicylate synthases perform isochorismate synthase and isochorismate-pyruvate lyase activities sequentially. While the active site residues are highly conserved, there are two sites that show trends for lyase-activity and lyase-deficiency. Using steady state kinetics and HPLC progress curves, we tested the "interchange" hypothesis that interconversion of the amino acids at these sites would promote lyase activity in the isochorismate synthases and remove lyase activity from the salicylate synthases. An alternative, "permute" hypothesis, that chorismate-utilizing enzymes are designed to permute the substrate into a variety of products and tampering with the active site may lead to identification of adventitious activities, is tested by more sensitive NMR time course experiments. The latter hypothesis held true. The variant enzymes predominantly catalyzed chorismate mutase-prephenate dehydratase activities, sequentially generating prephenate and phenylpyruvate, augmenting previously debated (mutase) or undocumented (dehydratase) adventitious activities.

  5. Ras-dependent and -independent pathways target the mitogen-activated protein kinase network in macrophages.

    PubMed Central

    Büscher, D; Hipskind, R A; Krautwald, S; Reimann, T; Baccarini, M

    1995-01-01

    Mitogen-activated protein kinases (MAPKs) are activated upon a variety of extracellular stimuli in different cells. In macrophages, colony-stimulating factor 1 (CSF-1) stimulates proliferation, while bacterial lipopolysaccharide (LPS) inhibits cell growth and causes differentiation and activation. Both CSF-1 and LPS rapidly activate the MAPK network and induce the phosphorylation of two distinct ternary complex factors (TCFs), TCF/Elk and TCF/SAP. CSF-1, but not LPS, stimulated the formation of p21ras. GTP complexes. Expression of a dominant negative ras mutant reduced, but did not abolish, CSF-1-mediated stimulation of MEK and MAPK. In contrast, activation of the MEK kinase Raf-1 was Ras independent. Treatment with the phosphatidylcholine-specific phospholipase C inhibitor D609 suppressed LPS-mediated, but not CSF-1-mediated, activation of Raf-1, MEK, and MAPK. Similarly, down-regulation or inhibition of protein kinase C blocked MEK and MAPK induction by LPS but not that by CSF-1. Phorbol 12-myristate 13-acetate pretreatment led to the sustained activation of the Raf-1 kinase but not that of MEK and MAPK. Thus, activated Raf-1 alone does not support MEK/MAPK activation in macrophages. Phosphorylation of TCF/Elk but not that of TCF/SAP was blocked by all treatments that interfered with MAPK activation, implying that TCF/SAP was targeted by a MAPK-independent pathway. Therefore, CSF-1 and LPS target the MAPK network by two alternative pathways, both of which induce Raf-1 activation. The mitogenic pathway depends on Ras activity, while the differentiation signal relies on protein kinase C and phosphatidylcholine-specific phospholipase C activation. PMID:7799956

  6. Effects of urine composition on epithelial Na+ channel-targeted protease activity

    PubMed Central

    Berman, Jonathan M; Awayda, Ryan G; Awayda, Mouhamed S

    2015-01-01

    We examined human urinary proteolytic activity toward the Epithelial Sodium Channel (ENaC). We focused on two sites in each of alpha and gamma ENaC that are targets of endogenous and exogenous proteases. We examined the effects of ionic strength, pH and urinary H+-buffers, metabolic intermediates, redox molecules, and large urinary proteins. Monoatomic cations caused the largest effect, with sodium inhibiting activity in the 15–515 mEq range. Multivalent cations zinc and copper inhibited urinary proteolytic activity at concentrations below 100 μmol/L. Similar to sodium, urea caused a 30% inhibition in the 0–500 mmol/L range. This was not observed with acetone and ethanol. Modulating urinary redox status modified activity with H2O2 stimulated and ascorbate inhibited activity. Minimal effects (<10%) were observed with caffeine, glucose, several TCA cycle intermediates, salicylic acid, inorganic phosphate, albumin, creatinine, and Tamm–Horsfall protein. The cumulative activity of ENaC-cleaving proteases was highest at neutral pH, however, alpha and gamma proteases exhibited an inverse dependence with alpha stimulated at acidic and gamma stimulated at alkaline pH. These data indicate that ENaC-targeting urinary proteolytic activity is sensitive to sodium, urea and pH and changes in these components can modify channel cleavage and activation status, and likely downstream sodium absorption unrelated to changes in protein or channel density. PMID:26564065

  7. Effects of urine composition on epithelial Na+ channel-targeted protease activity.

    PubMed

    Berman, Jonathan M; Awayda, Ryan G; Awayda, Mouhamed S

    2015-11-01

    We examined human urinary proteolytic activity toward the Epithelial Sodium Channel (ENaC). We focused on two sites in each of alpha and gamma ENaC that are targets of endogenous and exogenous proteases. We examined the effects of ionic strength, pH and urinary H(+)-buffers, metabolic intermediates, redox molecules, and large urinary proteins. Monoatomic cations caused the largest effect, with sodium inhibiting activity in the 15-515 mEq range. Multivalent cations zinc and copper inhibited urinary proteolytic activity at concentrations below 100 μmol/L. Similar to sodium, urea caused a 30% inhibition in the 0-500 mmol/L range. This was not observed with acetone and ethanol. Modulating urinary redox status modified activity with H2O2 stimulated and ascorbate inhibited activity. Minimal effects (<10%) were observed with caffeine, glucose, several TCA cycle intermediates, salicylic acid, inorganic phosphate, albumin, creatinine, and Tamm-Horsfall protein. The cumulative activity of ENaC-cleaving proteases was highest at neutral pH, however, alpha and gamma proteases exhibited an inverse dependence with alpha stimulated at acidic and gamma stimulated at alkaline pH. These data indicate that ENaC-targeting urinary proteolytic activity is sensitive to sodium, urea and pH and changes in these components can modify channel cleavage and activation status, and likely downstream sodium absorption unrelated to changes in protein or channel density. PMID:26564065

  8. Phishing for suitable targets in the Netherlands: routine activity theory and phishing victimization.

    PubMed

    Leukfeldt, E Rutger

    2014-08-01

    This article investigates phishing victims, especially the increased or decreased risk of victimization, using data from a cybercrime victim survey in the Netherlands (n=10,316). Routine activity theory provides the theoretical perspective. According to routine activity theory, several factors influence the risk of victimization. A multivariate analysis was conducted to assess which factors actually lead to increased risk of victimization. The model included background and financial data of victims, their Internet activities, and the degree to which they were "digitally accessible" to an offender. The analysis showed that personal background and financial characteristics play no role in phishing victimization. Among eight Internet activities, only "targeted browsing" led to increased risk. As for accessibility, using popular operating systems and web browsers does not lead to greater risk, while having up-to-date antivirus software as a technically capable guardian has no effect. The analysis showed no one, clearly defined group has an increased chance of becoming a victim. Target hardening may help, but opportunities for prevention campaigns aimed at a specific target group or dangerous online activities are limited. Therefore, situational crime prevention will have to come from a different angle. Banks could play the role of capable guardian.

  9. Modeling and production of 240Am by deuteron-induced activation of a 240Pu target

    SciTech Connect

    Finn, Erin C.; McNamara, Bruce K.; Greenwood, Lawrence R.; Wittman, Richard S.; Soderquist, Chuck Z.; Woods, Vincent T.; VanDevender, Brent A.; Metz, Lori A.; Friese, Judah I.

    2015-02-01

    A novel reaction pathway for production of 240Am is reported. Models of reaction cross-sections in EMPIRE II suggests that deuteron-induced activation of a 240Pu target produces maximum yields of 240Am from 11.5 MeV incident deuterons. This activation had not been previously reported in the literature. A 240Pu target was activated under the modeled optimum conditions to produce 240Am. The modeled cross-section for the 240Pu(d, 2n)240Am reaction is on the order of 20-30 mbarn, but the experimentally estimated value is 5.3 ± 0.2 mbarn. We discuss reasons for the discrepancy as well as production of other Am isotopes that contaminate the final product.

  10. Targeted activation of CREB in reactive astrocytes is neuroprotective in focal acute cortical injury.

    PubMed

    Pardo, Luis; Schlüter, Agatha; Valor, Luis M; Barco, Angel; Giralt, Mercedes; Golbano, Arantxa; Hidalgo, Juan; Jia, Peilin; Zhao, Zhongming; Jové, Mariona; Portero-Otin, Manuel; Ruiz, Montserrat; Giménez-Llort, Lydia; Masgrau, Roser; Pujol, Aurora; Galea, Elena

    2016-05-01

    The clinical challenge in acute injury as in traumatic brain injury (TBI) is to halt the delayed neuronal loss that occurs hours and days after the insult. Here we report that the activation of CREB-dependent transcription in reactive astrocytes prevents secondary injury in cerebral cortex after experimental TBI. The study was performed in a novel bitransgenic mouse in which a constitutively active CREB, VP16-CREB, was targeted to astrocytes with the Tet-Off system. Using histochemistry, qPCR, and gene profiling we found less neuronal death and damage, reduced macrophage infiltration, preserved mitochondria, and rescued expression of genes related to mitochondrial metabolism in bitransgenic mice as compared to wild type littermates. Finally, with meta-analyses using publicly available databases we identified a core set of VP16-CREB candidate target genes that may account for the neuroprotective effect. Enhancing CREB activity in astrocytes thus emerges as a novel avenue in acute brain post-injury therapeutics.

  11. 40 CFR 745.226 - Certification of individuals and firms engaged in lead-based paint activities: target housing and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN RESIDENTIAL STRUCTURES Lead-Based Paint Activities § 745.226 Certification of individuals and firms engaged in lead-based paint activities: target housing... engaged in lead-based paint activities: target housing and child-occupied facilities. 745.226 Section...

  12. 40 CFR 745.226 - Certification of individuals and firms engaged in lead-based paint activities: target housing and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN RESIDENTIAL STRUCTURES Lead-Based Paint Activities § 745.226 Certification of individuals and firms engaged in lead-based paint activities: target housing... engaged in lead-based paint activities: target housing and child-occupied facilities. 745.226 Section...

  13. 40 CFR 745.226 - Certification of individuals and firms engaged in lead-based paint activities: target housing and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN RESIDENTIAL STRUCTURES Lead-Based Paint Activities § 745.226 Certification of individuals and firms engaged in lead-based paint activities: target housing... engaged in lead-based paint activities: target housing and child-occupied facilities. 745.226 Section...

  14. Utilizing G2/M retention effect to enhance tumor accumulation of active targeting nanoparticles

    PubMed Central

    Hu, Guanlian; Cun, Xingli; Ruan, Shaobo; Shi, Kairong; Wang, Yang; Kuang, Qifang; Hu, Chuan; Xiao, Wei; He, Qin; Gao, Huile

    2016-01-01

    In recent years, active targeting strategies by ligand modification have emerged to enhance tumor accumulation of NP, but their clinical application was strictly restricted due to the complex preparation procedures, poor stability and serious toxicity. An effective and clinical translational strategy is required to satisfy the current problems. Interestingly, the internalization of NP is intimately related with cell cycle and the expression of receptors is not only related with cancer types but also cell cycle progression. So the cellular uptake of ligand modified NP may be related with cell cycle. However, few investigations were reported about the relationship between cell cycle and the internalization of ligand modified NP. Herein, cellular uptake of folic acid (FA) modified NP after utilizing chemotherapeutic to retain the tumor cells in G2/M phase was studied and a novel strategy was designed to enhance the active targeting effect. In our study, docetaxel (DTX) notably synchronized cells in G2/M phase and pretreatment with DTX highly improved in vitro and in vivo tumor cell targeting effect of FA decorated NP (FANP). Since FA was a most common used tumor active targeting ligand, we believe that this strategy possesses broader prospects in clinical application for its simplicity and effectiveness. PMID:27273770

  15. Rapid shifts of sonar attention by Pipistrellus abramus during natural hunting for multiple prey.

    PubMed

    Fujioka, Emyo; Aihara, Ikkyu; Watanabe, Shotaro; Sumiya, Miwa; Hiryu, Shizuko; Simmons, James A; Riquimaroux, Hiroshi; Watanabe, Yoshiaki

    2014-12-01

    Flight paths of echolocating Japanese house bats, Pipistrellus abramus, were tracked during insect hunting in a natural setting using a 32-microphone array. The array surrounded the foraging area, locating each bat, and determined the directional aim of the sonar beam. Successive interceptions, indicated by feeding "buzzes" and post-buzz pauses, occurred singly at intervals from over 20 s down to multiple interceptions at 2-3 s intervals. Bats flew on looping, curved paths. Turning radius tightened as rate of interceptions increased, keeping the bat in a smaller area of higher capture density. Broadcast beams shifted direction during search, often alternating between the direction of flight and another direction where, moments later, the next interception would occur. Broadcasts also shifted direction between the current target and the next target. Bats time-share biosonar attention between objects by alternating acoustic gaze. During search, most interpulse intervals (IPIs) were 70-120 ms, but bats interspersed long IPIs up to 200 ms when the rate of interception was low and flight paths followed broad curves. Mathematical modeling of search paths demonstrated that circular flight-paths with occasional long IPIs would be more effective for target search than either random, correlated random, or linear flights. PMID:25480083

  16. Rapid shifts of sonar attention by Pipistrellus abramus during natural hunting for multiple prey.

    PubMed

    Fujioka, Emyo; Aihara, Ikkyu; Watanabe, Shotaro; Sumiya, Miwa; Hiryu, Shizuko; Simmons, James A; Riquimaroux, Hiroshi; Watanabe, Yoshiaki

    2014-12-01

    Flight paths of echolocating Japanese house bats, Pipistrellus abramus, were tracked during insect hunting in a natural setting using a 32-microphone array. The array surrounded the foraging area, locating each bat, and determined the directional aim of the sonar beam. Successive interceptions, indicated by feeding "buzzes" and post-buzz pauses, occurred singly at intervals from over 20 s down to multiple interceptions at 2-3 s intervals. Bats flew on looping, curved paths. Turning radius tightened as rate of interceptions increased, keeping the bat in a smaller area of higher capture density. Broadcast beams shifted direction during search, often alternating between the direction of flight and another direction where, moments later, the next interception would occur. Broadcasts also shifted direction between the current target and the next target. Bats time-share biosonar attention between objects by alternating acoustic gaze. During search, most interpulse intervals (IPIs) were 70-120 ms, but bats interspersed long IPIs up to 200 ms when the rate of interception was low and flight paths followed broad curves. Mathematical modeling of search paths demonstrated that circular flight-paths with occasional long IPIs would be more effective for target search than either random, correlated random, or linear flights.

  17. Adaptive large-scale clutter removal from imagery with application to high-resolution sonar imagery

    NASA Astrophysics Data System (ADS)

    Dobeck, Gerald J.

    2010-04-01

    The ability to reliably detect targets having signatures comprised of bright pixels (highlight) and dark pixels (shadow) is challenging when the background texture of the imagery also possesses bright and dark characteristics. This is especially difficult when the background contains large bright and dark areas that can mask target signatures. Detection and classification algorithms would benefit from an adaptive denoising algorithm that would remove or mitigate such background artifacts. This paper presents a Fourier-based denoising algorithm. The large support of the Fourier basis is used to capture and remove large-scale artifacts while leaving the smaller target-size features nearly unchanged. Datadriven soft thresholds allow the algorithm to automatically adapt to changing backgrounds. Preliminary investigations have demonstrated excellent performance. The algorithm is computationally fast and suitable for real-time application. The denoising algorithm is general in nature and can be applied to many types of high-resolution gray-scale imagery; e.g., side-looking sonar and SAR.

  18. Effects of Epstein's TARGET on adolescents' intentions to be physically active and leisure-time physical activity.

    PubMed

    Cecchini, Jose A; Fernandez-Rio, Javier; Mendez-Gimenez, Antonio

    2014-06-01

    The aim of this study was to examine the effects of Epstein's TARGET strategies on adolescents' intentions to be physically active and leisure-time physical activity (LTPA) levels. A total of 447 secondary education students (193 females and 254 males), range age 12-17 years, were divided in two groups: control (N = 224) and experimental (N = 223). Epstein's TARGET strategies were applied by especially trained teachers only to the experimental group in their physical education (PE) classes during 12 consecutive weeks. Participants' intentions to be physically active and their LTPA levels were assessed prior to the intervention (pre), at the end of it (post-1) and 3 months after the intervention (post-2). Significant increases were observed only in the experimental group in post-1 and post-2 on both variables. PE interventions based on TARGET strategies seem to be effective increasing adolescents' intentions to be physically active, as well as time spent in LTPA. As most adolescents participate in PE, these interventions could lead to substantial public health benefits.

  19. Coherent broadband sonar signal processing with the environmentally corrected matched filter

    NASA Astrophysics Data System (ADS)

    Camin, Henry John, III

    The matched filter is the standard approach for coherently processing active sonar signals, where knowledge of the transmitted waveform is used in the detection and parameter estimation of received echoes. Matched filtering broadband signals provides higher levels of range resolution and reverberation noise suppression than can be realized through narrowband processing. Since theoretical processing gains are proportional to the signal bandwidth, it is typically desirable to utilize the widest band signals possible. However, as signal bandwidth increases, so do environmental effects that tend to decrease correlation between the received echo and the transmitted waveform. This is especially true for ultra wideband signals, where the bandwidth exceeds an octave or approximately 70% fractional bandwidth. This loss of coherence often results in processing gains and range resolution much lower than theoretically predicted. Wiener filtering, commonly used in image processing to improve distorted and noisy photos, is investigated in this dissertation as an approach to correct for these environmental effects. This improved signal processing, Environmentally Corrected Matched Filter (ECMF), first uses a Wiener filter to estimate the environmental transfer function and then again to correct the received signal using this estimate. This process can be viewed as a smarter inverse or whitening filter that adjusts behavior according to the signal to noise ratio across the spectrum. Though the ECMF is independent of bandwidth, it is expected that ultra wideband signals will see the largest improvement, since they tend to be more impacted by environmental effects. The development of the ECMF and demonstration of improved parameter estimation with its use are the primary emphases in this dissertation. Additionally, several new contributions to the field of sonar signal processing made in conjunction with the development of the ECMF are described. A new, nondimensional wideband

  20. Bedload Hysteresis and Bedform Deformation Rates Investigated with Physical Samples, Multibeam Sonar, and Seismic Monitoring

    NASA Astrophysics Data System (ADS)

    Gaeuman, D.; Schmandt, B.; Stewart, R. L.; Pryor, C.

    2015-12-01

    Field and laboratory observations indicate that bedload transport frequently exhibits clockwise hysteresis. Several grain-scale mechanisms could account for this, including increases in the median surface particle size, development of stable particle arrangements on the bed surface, or reductions in the sediment supply. Alternatively, bedload hysteresis at steady flow could occur if the bed configuration stabilizes as bedforms approach a configuration that is in quasi-equilibrium with prevailing hydraulic conditions. The roles of bedform development and changes in coarse sediment availability as potential causes of hysteresis are investigated with a unique dataset obtained during a high flow release in the Trinity River, a regulated gravel-bed river in California. Physical bedload samples were obtained over the release hydrograph along with continuous seismic monitoring with 3-component broadband seismometers at four locations along the river. At one location, changes in bed topography during the peak of the release were monitored with repeated multibeam sonar surveys over a channel length of about 1 km. In addition, a network of 80 vertical-component seismometers was deployed adjacent to the channel to support development of a time series of maps showing local variations in seismic energy production on the stream bed. Finally, a gravel augmentation operation was being implemented at the upstream end of the reach during the release peak, permitting evaluation of how changes in sediment supply affect downstream transport rates. Sampled bedload transport rates were found to increase briefly during gravel augmentation operations, but return to pre-augmentation levels within a few hours after augmentation activities stop and generally decline over a period of peak flow lasting about 3 days. The sonar data indicate that most of the topographic change observed during the peak flow period occurred in the first several hours of the period, supporting the hypothesis that

  1. Evaluation of the biological activity of the molluscicidal fraction of Solanum sisymbriifolium against non target organisms.

    PubMed

    Bagalwa, Jean-Jacques M; Voutquenne-Nazabadioko, Laurence; Sayagh, Charlotte; Bashwira, Augustin S

    2010-10-01

    The evaluation of the biocidal activity of the fruit of Solanum sisymbriifolium involving non target organisms such as aquatic insects, fish and snails lead to the isolation of the steroidal alkaloids, solamargine and β-solamarine, from the active fractions. The fractions A3 and C, with biological activity against fish, snail and aquatic insect and larvae, are able to affect the good functioning of ecosystem found on alimentary chain. The fraction B seems to be less toxic to fish and aquatic insect and larvae. The fraction B could thus be used as molluscicide in the future. PMID:20388535

  2. Anti-complementary constituents of Houttuynia cordata and their targets in complement activation cascade.

    PubMed

    Jiang, Yun; Lu, Yan; Zhang, Yun-Yi; Chen, Dao-Feng

    2014-01-01

    Activity-guided fractionation for complement inhibitors led to the isolation of 23 known compounds from Houttuynia cordata Thunb. Seven flavonoids, two alkaloids, one coumarin and two phenols showed anti-complementary activity. Preliminary inhibitory mechanism of four flavonoids, including quercitrin, afzelin, isoquercitrin and quercetin in the complement activation cascade were examined for the first time. The results indicated that the target components of flavonols are different from those of flavonosides, and the glycoside moieties may be necessary to block C3 and C4 components. PMID:24423008

  3. Binaural sonar electronic travel aid provides vibrotactile cues for landmark, reflector motion and surface texture classification.

    PubMed

    Kuc, Roman

    2002-10-01

    Electronic travel aids (ETAs) for the blind commonly employ conventional time-of-flight sonars to provide range measurements, but their wide beams prevent accurate determination of object bearing. We describe a binaural sonar that detects objects over a wider bearing interval compared with a single transducer and also determines if the object lies to the left or right of the sonar axis in a robust manner. The sonar employs a pair of Polaroid 6500 ranging modules connected to Polaroid 7000 transducers operating simultaneously in a binaural array configuration. The sonar determines which transducer detects the echo first. An outward vergence angle between the transducers improves the first-echo detection reliability by increasing the delay between the two detected echoes, a consequence of threshold detection. We exploit this left/right detection capability in an ETA that provides vibrotactile feedback. Pager motors mount on both sides of the sonar, possibly worn on the user's wrists. The motor on the same side as the reflecting object vibrates with speed inversely related to range. As the sonar or object moves, vibration patterns provide landmark, motion and texture cues. Orienting the sonar at 45 degrees relative to the travel direction and passing a right-angle corner produces a characteristic vibrational pattern. When pointing the sonar at a moving object, such as a fluttering flag, the motors alternate in a manner to give the user a perception of the object motion. When the sonar translates or rotates to scan a foliage surface, the vibrational patterns are related to the surface scatterer distribution, allowing the user to identify the foliage.

  4. Target cell death triggered by cytotoxic T lymphocytes: a target cell mutant distinguishes passive pore formation and active cell suicide mechanisms.

    PubMed Central

    Ucker, D S; Wilson, J D; Hebshi, L D

    1994-01-01

    The role of the target cell in its own death mediated by cytotoxic T lymphocytes (CTL) has been controversial. The ability of the pore-forming granule components of CTL to induce target cell death directly has been taken to suggest an essentially passive role for the target. This view of CTL-mediated killing ascribes to the target the single role of providing an antigenic stimulus to the CTL; this signal results in the vectoral degranulation and secretion of pore-forming elements onto the target. On the other hand, by a number of criteria, target cell death triggered by CTL appears fundamentally different from death resulting from membrane damage and osmotic lysis. CTL-triggered target cell death involves primary internal lesions of the target cell that reflect a physiological cell death process. Orderly nuclear disintegration, including lamin phosphorylation and solubilization, chromatin condensation, and genome digestion, are among the earliest events, preceding the loss of plasma membrane integrity. We have tested directly the involvement of the target cell in its own death by examining whether we could isolate mutants of target cells that have retained the ability to be recognized by and provide an antigenic stimulus to CTL while having lost the capacity to respond by dying. Here, we describe one such mutant, BW87. We have used this CTL-resistant mutant to analyze the mechanisms of CTL-triggered target cell death under a variety of conditions. The identification of a mutable target cell element essential for the cell death response to CTL provides genetic evidence that target cell death reflects an active cell suicide process similar to other physiological cell deaths. PMID:8264610

  5. Static analysis of a sonar dome rubber window

    NASA Technical Reports Server (NTRS)

    Lai, J. L.

    1978-01-01

    The application of NASTRAN (level 16.0.1) to the static analysis of a sonar dome rubber window (SDRW) was demonstrated. The assessment of the conventional model (neglecting the enclosed fluid) for the stress analysis of the SDRW was made by comparing its results to those based on a sophisticated model (including the enclosed fluid). The fluid was modeled with isoparametric linear hexahedron elements with approximate material properties whose shear modulus was much smaller than its bulk modulus. The effect of the chosen material property for the fluid is discussed.

  6. Extraction of small boat harmonic signatures from passive sonar.

    PubMed

    Ogden, George L; Zurk, Lisa M; Jones, Mark E; Peterson, Mary E

    2011-06-01

    This paper investigates the extraction of acoustic signatures from small boats using a passive sonar system. Noise radiated from a small boats consists of broadband noise and harmonically related tones that correspond to engine and propeller specifications. A signal processing method to automatically extract the harmonic structure of noise radiated from small boats is developed. The Harmonic Extraction and Analysis Tool (HEAT) estimates the instantaneous fundamental frequency of the harmonic tones, refines the fundamental frequency estimate using a Kalman filter, and automatically extracts the amplitudes of the harmonic tonals to generate a harmonic signature for the boat. Results are presented that show the HEAT algorithms ability to extract these signatures.

  7. Sonar and its Use in Kidney Disease in Children

    PubMed Central

    Lyons, E. A.; Murphy, A. V.; Arneil, G. C.

    1972-01-01

    The basic principles of diagnostic ultrasound or sonar are given, together with the special technique required for scanning newborn infants and small children for kidney abnormalities. Illustrative examples of the potential of this procedure, both in diagnosis and in monitoring changes include a normal neonatal and preadolescent kidney, unilateral renal agenesis, duplex kidney, renal cyst, polycystic disease, nephroblastoma, and examples of mild and severe hydronephrosis. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5FIG. 6FIG. 7FIG. 8FIG. 9FIG. 10FIG. 11FIG. 12 PMID:4343783

  8. Sonar biparietal diameter growth standards in the rhesus monkey.

    PubMed

    Sabbagha, R E; Turner, J H; Chez, R A

    1975-02-01

    Serial sonar fetal cephalometry was performed on 67 pregnant monkeys (Macaca ulatta) with known breeding dates. A normal biparietal diameter (BPD) growth curve was constructed along four percentile divisions; namely, the 10th to the 24th, 25th to the 49th, 50th to the 74th, and the 75th to the 90th. It is shown that under normal conditions fetuses initially positioned in any one of these divisions will continue to grow within the confines of that same percentile range. This biologic phenomenon has not been previously reported. It is significant because it leads to a more precise separation of normal vs. suboptimal intrauterine growth.

  9. Resistance of Cancer Cells to Targeted Therapies Through the Activation of Compensating Signaling Loops.

    PubMed

    von Manstein, Viktoria; Yang, Chul Min; Richter, Diane; Delis, Natalia; Vafaizadeh, Vida; Groner, Bernd

    2013-12-01

    The emergence of low molecular weight kinase inhibitors as "targeted" drugs has led to remarkable advances in the treatment of cancer patients. The clinical benefits of these tumor therapies, however, vary widely in patient populations and with duration of treatment. Intrinsic and acquired resistance against such drugs limits their efficacy. In addition to the well studied mechanisms of resistance based upon drug transport and metabolism, genetic alterations in drug target structures and the activation of compensatory cell signaling have received recent attention. Adaptive responses can be triggered which counteract the initial dependence of tumor cells upon a particular signaling molecule and allow only a transient inhibition of tumor cell growth. These compensating signaling mechanisms are often based upon the relief of repression of regulatory feedback loops. They might involve cell autonomous, intracellular events or they can be mediated via the secretion of growth factor receptor ligands into the tumor microenvironment and signal induction in an auto- or paracrine fashion. The transcription factors Stat3 and Stat5 mediate the biological functions of cytokines, interleukins and growth factors and can be considered as endpoints of multiple signaling pathways. In normal cells this activation is transient and the Stat molecules return to their non-phosphorylated state within a short time period. In tumor cells the balance between activating and de-activating signals is disturbed resulting in the persistent activation of Stat3 or Stat5. The constant activation of Stat3 induces the expression of target genes, which cause the proliferation and survival of cancer cells, as well as their migration and invasive behavior. Activating components of the Jak-Stat pathway have been recognized as potentially valuable drug targets and important principles of compensatory signaling circuit induction during targeted drug treatment have been discovered in the context of kinase

  10. Recent Developments in Active Tumor Targeted Multifunctional Nanoparticles for Combination Chemotherapy in Cancer Treatment and Imaging

    PubMed Central

    Glasgow, Micah D. K.; Chougule, Mahavir B.

    2016-01-01

    Nanotechnology and combination therapy are two major fields that show great promise in the treatment of cancer. The delivery of drugs via nanoparticles helps to improve drug’s therapeutic effectiveness while reducing adverse side effects associated with high dosage by improving their pharmacokinetics. Taking advantage of molecular markers over-expressing on tumor tissues compared to normal cells, an “active” molecular marker targeted approach would be beneficial for cancer therapy. These actively targeted nanoparticles would increase drug concentration at the tumor site, improving efficacy while further reducing chemo-resistance. The multidisciplinary approach may help to improve the overall efficacy in cancer therapy. This review article summarizes recent developments of targeted multifunctional nanoparticles in the delivery of various drugs for a combinational chemotherapy approach to cancer treatment and imaging. PMID:26554150

  11. Programmed activation of cancer cell apoptosis: A tumor-targeted phototherapeutic topoisomerase I inhibitor.

    PubMed

    Shin, Weon Sup; Han, Jiyou; Kumar, Rajesh; Lee, Gyung Gyu; Sessler, Jonathan L; Kim, Jong-Hoon; Kim, Jong Seung

    2016-01-01

    We report here a tumor-targeting masked phototherapeutic agent 1 (PT-1). This system contains SN-38-a prodrug of the topoisomerase I inhibitor irinotecan. Topoisomerase I is a vital enzyme that controls DNA topology during replication, transcription, and recombination. An elevated level of topoisomerase I is found in many carcinomas, making it an attractive target for the development of effective anticancer drugs. In addition, PT-1 contains both a photo-triggered moiety (nitrovanillin) and a cancer targeting unit (biotin). Upon light activation in cancer cells, PT-1 interferes with DNA re-ligation, diminishes the expression of topoisomerase I, and enhances the expression of inter alia mitochondrial apoptotic genes, death receptors, and caspase enzymes, inducing DNA damage and eventually leading to apoptosis. In vitro and in vivo studies showed significant inhibition of cancer growth and the hybrid system PT-1 thus shows promise as a programmed photo-therapeutic ("phototheranostic"). PMID:27374023

  12. Programmed activation of cancer cell apoptosis: A tumor-targeted phototherapeutic topoisomerase I inhibitor

    NASA Astrophysics Data System (ADS)

    Shin, Weon Sup; Han, Jiyou; Kumar, Rajesh; Lee, Gyung Gyu; Sessler, Jonathan L.; Kim, Jong-Hoon; Kim, Jong Seung

    2016-07-01

    We report here a tumor-targeting masked phototherapeutic agent 1 (PT-1). This system contains SN-38—a prodrug of the topoisomerase I inhibitor irinotecan. Topoisomerase I is a vital enzyme that controls DNA topology during replication, transcription, and recombination. An elevated level of topoisomerase I is found in many carcinomas, making it an attractive target for the development of effective anticancer drugs. In addition, PT-1 contains both a photo-triggered moiety (nitrovanillin) and a cancer targeting unit (biotin). Upon light activation in cancer cells, PT-1 interferes with DNA re-ligation, diminishes the expression of topoisomerase I, and enhances the expression of inter alia mitochondrial apoptotic genes, death receptors, and caspase enzymes, inducing DNA damage and eventually leading to apoptosis. In vitro and in vivo studies showed significant inhibition of cancer growth and the hybrid system PT-1 thus shows promise as a programmed photo-therapeutic (“phototheranostic”).

  13. Programmed activation of cancer cell apoptosis: A tumor-targeted phototherapeutic topoisomerase I inhibitor

    PubMed Central

    Shin, Weon Sup; Han, Jiyou; Kumar, Rajesh; Lee, Gyung Gyu; Sessler, Jonathan L.; Kim, Jong-Hoon; Kim, Jong Seung

    2016-01-01

    We report here a tumor-targeting masked phototherapeutic agent 1 (PT-1). This system contains SN-38—a prodrug of the topoisomerase I inhibitor irinotecan. Topoisomerase I is a vital enzyme that controls DNA topology during replication, transcription, and recombination. An elevated level of topoisomerase I is found in many carcinomas, making it an attractive target for the development of effective anticancer drugs. In addition, PT-1 contains both a photo-triggered moiety (nitrovanillin) and a cancer targeting unit (biotin). Upon light activation in cancer cells, PT-1 interferes with DNA re-ligation, diminishes the expression of topoisomerase I, and enhances the expression of inter alia mitochondrial apoptotic genes, death receptors, and caspase enzymes, inducing DNA damage and eventually leading to apoptosis. In vitro and in vivo studies showed significant inhibition of cancer growth and the hybrid system PT-1 thus shows promise as a programmed photo-therapeutic (“phototheranostic”). PMID:27374023

  14. Characteristics of a sandy depositional lobe on the outer Mississippi fan from SeaMARC IA sidescan sonar images

    USGS Publications Warehouse

    Twichell, David C.; Schwab, William C.; Nelson, C. Hans; Kenyon, Neil H.; Lee, Homa J.

    1992-01-01

    SeaMARC IA sidescan sonar images of the distal reaches of a depositional lobe on the Mississippi Fan show that channelized rather than unconfined transport was the dominant transport mechanism for coarse-grained sediment during the formation of this part of the deep-sea fan. Overbank sheet flow of sands was not an important process in the transport and deposition of the sandy and silty sediment found on this fan. The dendritic distributary pattern and the high order of splaying of the channels, only one of which appears to have been active at a time, suggest that coarse-grained deposits on this fan are laterally discontinuous.

  15. Characteristics of a sandy depositional lobe on the outer Mississippi fan from SeaMARC IA sidescan sonar images

    SciTech Connect

    Twichell, D.C.; Schwab, W.C. ); Nelson, C.H.; Lee, H.J. ); Kenyon, N.H. )

    1992-08-01

    SeaMARC IA sidescan sonar images of the distal reaches of a depositional lobe on the Mississippi Fan show that channelized rather than unconfined transport was the dominant transport mechanism for coarse-grained sediment during the formation of this part of the deep-sea fan. Overbank sheet flow of sands was not an important process in the transport and deposition of the sandy and silty sediment found on this fan. The dendritic distributary pattern and the high order of splaying of the channels, only one which appears to have been active at a time, suggest that coarse-grained deposits on this fan are laterally discontinuous.

  16. Evaluating Transcription Factor Activity Changes by Scoring Unexplained Target Genes in Expression Data

    PubMed Central

    Berchtold, Evi; Csaba, Gergely; Zimmer, Ralf

    2016-01-01

    Several methods predict activity changes of transcription factors (TFs) from a given regulatory network and measured expression data. But available gene regulatory networks are incomplete and contain many condition-dependent regulations that are not relevant for the specific expression measurement. It is not known which combination of active TFs is needed to cause a change in the expression of a target gene. A method to systematically evaluate the inferred activity changes is missing. We present such an evaluation strategy that indicates for how many target genes the observed expression changes can be explained by a given set of active TFs. To overcome the problem that the exact combination of active TFs needed to activate a gene is typically not known, we assume a gene to be explained if there exists any combination for which the predicted active TFs can possibly explain the observed change of the gene. We introduce the i-score (inconsistency score), which quantifies how many genes could not be explained by the set of activity changes of TFs. We observe that, even for these minimal requirements, published methods yield many unexplained target genes, i.e. large i-scores. This holds for all methods and all expression datasets we evaluated. We provide new optimization methods to calculate the best possible (minimal) i-score given the network and measured expression data. The evaluation of this optimized i-score on a large data compendium yields many unexplained target genes for almost every case. This indicates that currently available regulatory networks are still far from being complete. Both the presented Act-SAT and Act-A* methods produce optimal sets of TF activity changes, which can be used to investigate the difficult interplay of expression and network data. A web server and a command line tool to calculate our i-score and to find the active TFs associated with the minimal i-score is available from https://services.bio.ifi.lmu.de/i-score. PMID:27723775

  17. Microparticle Surface Modifications Targeting Dendritic Cells for Non-Activating Applications

    PubMed Central

    Lewis, Jamal S.; Zaveri, Toral D.; Crooks, Charles P.; Keselowsky, Benjamin G.

    2012-01-01

    Microparticulate systems for delivery of therapeutics to DCs for immunotherapy have gained attention recently. However, reports addressing the optimization of DC-targeting microparticle delivery systems are limited, particularly for cases where the goal is to deliver payload to DCs in a non-activating fashion. Here, we investigate targeting DCs using poly (d lactide-co-glycolide) microparticles (MPs) in a non-stimulatory manner and assess efficacy in vitro and in vivo. We modified MPs by surface immobilizing DC receptor targeting molecules – antibodies (anti-CD11c, anti-DEC-205) or peptides (P-D2, RGD), where anti-CD11c antibody, P-D2 and RGD peptides target integrins and anti-DEC-205 antibody targets the c-type lectin receptor DEC-205. Our results demonstrate the modified MPs are neither toxic nor activating, and DC uptake of MPs in vitro is improved by the anti-DEC-205 antibody, the anti-CD11c antibody and the P-D2 peptide modifications. The P-D2 peptide MP modification significantly improved DC antigen presentation in vitro both at immediate and delayed time points. Notably, MP functionalization with P-D2 peptide and anti-CD11c antibody increased the rate and extent of MP translocation in vivo by DCs and MΦs, with the P-D2 peptide modified MPs demonstrating the highest translocation. This work informs the design of non-activating polymeric microparticulate applications such as vaccines for autoimmune diseases. PMID:22796161

  18. Targeting Inhibition of Fibroblast Activation Protein-α and Prolyl Oligopeptidase Activities on Cells Common to Metastatic Tumor Microenvironments1

    PubMed Central

    Christiansen, Victoria J; Jackson, Kenneth W; Lee, Kyung N; Downs, Tamyra D; McKee, Patrick A

    2013-01-01

    Fibroblast activation protein (FAP), a membrane prolyl-specific proteinase with both dipeptidase and endopeptidase activities, is overexpressed by reactive stromal fibroblasts during epithelial-derived cancer growth. FAP digests extracellular matrix as tissue is remodeled during cancer expansion and may also promote an immunotolerant tumor microenvironment. Recent studies suggest that nonspecific FAP inhibitors suppress human cancer xenografts in mouse models. Prolyl oligopeptidase (POP), another prolyl-specific serine proteinase, is also elevated in many cancers and may have a regulatory role in angiogenesis promotion. FAP and POP cell-associated activities may be targets for diagnosis and treatment of various cancers, but their accessibilities to highly effective specific inhibitors have not been shown for cells important to cancer growth. Despite their frequent simultaneous expression in many cancers and their overlapping activities toward commonly used substrates, precise, separate measurement of FAP or POP activity has largely been ignored. To distinguish each of the two activities, we synthesized highly specific substrates and inhibitors for FAP or POP based on amino acid sequences surrounding the scissile bonds of their respective putative substrates. We found varying amounts of FAP and POP protein and activities on activated fibroblasts, mesenchymal cells, normal breast cells, and one breast cancer cell line, with some cells exhibiting more POP than FAP activity. Replicating endothelial cells (ECs) expressed POP but not FAP until tubulogenesis began. Targeting FAP-positive cells, especially mesenchymal stem cells and cancer-associated fibroblasts for inactivation or destruction, and inhibiting POP-producing EC may abrogate stromal invasion and angiogenesis simultaneously and thereby diminish cancer growth. PMID:23555181

  19. Mechanisms of nonhormonal activation of adenylate cyclase based on target analysis

    SciTech Connect

    Verkman, A.S.; Ausiello, D.A.; Jung, C.Y.; Skorecki, K.L.

    1986-08-12

    Radiation inactivation was used to examine the mechanism of activation of adenylate cyclase in the cultured renal epithelial cell line LLC-PK1 with hormonal (vasopressin) and nonhormonal (GTP, forskolin, fluoride, and chloride) activating ligands. Intact cells were frozen, irradiated at -70 degrees C (0-14 Mrad), thawed, and assayed for adenylate cyclase activity in the presence of activating ligands. The ln (adenylate cyclase activity) vs. radiation dose relation was linear (target size 162 kDa) for vasopressin- (2 microM) stimulated activity and concave downward for unstimulated (10 mM Mn/sup 2 +/), NaF- (10 mM) stimulated, and NaCl- (100 mM) stimulated activities. Addition of 2 microM vasopressin did not alter the ln activity vs. dose relation for NaF- (10 mM) stimulated activity. The dose-response relations for adenylate cyclase activation and for transition in the ln activity vs. dose curve shape were measured for vasopressin and NaF. On the basis of our model for adenylate cyclase subunit interactions reported previously (Verkman, A. S., Skorecki, K. L., and Ausiello, D. A. (1986) Am. J. Physiol. 260, C103-C123) and of new mathematical analyses, activation mechanisms for each ligand are proposed. In the unstimulated state, equilibrium between alpha beta and alpha + beta favors alpha beta; dissociated alpha binds to GTP (rate-limiting step), which then combines with the catalytic (C) subunit to form active enzyme. Vasopressin binding to receptor provides a rapid pathway for GTP binding to alpha. GTP and its analogues accelerate the rate of alpha GTP formation. Forskolin inhibits the spontaneous deactivation of activated C. Activation by fluoride may occur without alpha beta dissociation or GTP addition through activation of C by an alpha beta-F complex.

  20. Cerebellar brain inhibition in the target and surround muscles during voluntary tonic activation.

    PubMed

    Panyakaew, Pattamon; Cho, Hyun Joo; Srivanitchapoom, Prachaya; Popa, Traian; Wu, Tianxia; Hallett, Mark

    2016-04-01

    Motor surround inhibition is the neural mechanism that selectively favours the contraction of target muscles and inhibits nearby muscles to prevent unwanted movements. This inhibition was previously reported at the onset of a movement, but not during a tonic contraction. Cerebellar brain inhibition (CBI) is reduced in active muscles during tonic activation; however, it has not been studied in the surround muscles. CBI was evaluated in the first dorsal interosseus (FDI) muscle as the target muscle, and the abductor digiti minimi, flexor carpi radialis and extensor carpi radialis muscles as surround muscles, during rest and tonic activation of the FDI muscle in 21 subjects. Cerebellar stimulation was performed under magnetic resonance imaging-guided neuronavigation targeting lobule VIII of the cerebellar hemisphere. Stimulus intensities for cerebellar stimulation were based on the resting motor cortex threshold (RMT) and adjusted for the depth difference between the cerebellar and motor cortices. We used 90-120% of the adjusted RMT as the conditioning stimulus intensity during rest. The intensity that generated the best CBI at rest in the FDI muscle was selected for use during tonic activation. During selective tonic activation of the FDI muscle, CBI was significantly reduced only for the FDI muscle, and not for the surround muscles. Unconditioned motor evoked potential sizes were increased in all muscles during FDI muscle tonic activation as compared with rest, despite background electromyography activity increasing only for the FDI muscle. Our study suggests that the cerebellum may play an important role in selective tonic finger movement by reducing its inhibition in the motor cortex only for the relevant agonist muscle.