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Sample records for capturing blocked-entrance binaural

  1. Binaural beat salience

    PubMed Central

    Grose, John H.; Buss, Emily; Hall, Joseph W.

    2012-01-01

    Previous studies of binaural beats have noted individual variability and response lability, but little attention has been paid to the salience of the binaural beat percept. The purpose of this study was to gauge the strength of the binaural beat percept by matching its salience to that of sinusoidal amplitude modulation (SAM), and to then compare rate discrimination for the two types of fluctuation. Rate discrimination was measured for standard rates of 4, 8, 16, and 32 Hz – all in the 500-Hz carrier region. Twelve normal-hearing adults participated in this study. The results indicated that discrimination acuity for binaural beats is similar to that for SAM tones whose depths of modulation have been adjusted to provide equivalent modulation salience. The matched-salience SAM tones had relatively shallow depths of modulation, suggesting that the perceptual strength of binaural beats is relatively weak, although all listeners perceived them. The Weber fraction for detection of an increase in binaural beat rate is roughly constant across beat rates, at least for rates above 4 Hz, as is rate discrimination for SAM tones. PMID:22326292

  2. Binaural Loudness Constancy.

    PubMed

    Culling, John F; Dare, Helen

    2016-01-01

    In binaural loudness summation, diotic presentation of a sound usually produces greater loudness than monaural presentation. However, experiments using loudspeaker presentation with and without earplugs find that magnitude estimates of loudness are little altered by the earplug, suggesting a form of loudness constancy. We explored the significance of controlling stimulation of the second ear using meatal occlusion as opposed to the deactivation of one earphone. We measured the point of subjective loudness equality (PSLE) for monaural vs. binaural presentation using an adaptive technique for both speech and noise. These stimuli were presented in a reverberant room over a loudspeaker to the right of the listener, or over lightweight headphones. Using the headphones, stimuli were either presented dry, or matched to those of the loudspeaker by convolution with impulse responses measured from the loudspeaker to the listener position, using an acoustic manikin. The headphone response was also compensated. Using the loudspeaker, monaural presentation was achieved by instructing the listener to block the left ear with a finger. Near perfect binaural loudness constancy was observed using loudspeaker presentation, while there was a summation effect of 3-6 dB for both headphone conditions. However, only partial constancy was observed when meatal occlusion was simulated. These results suggest that there may be contributions to binaural loudness constancy from residual low frequencies at the occluded ear as well as a cognitive element, which is activated by the knowledge that one ear is occluded. PMID:27080647

  3. Binaural room simulation

    NASA Technical Reports Server (NTRS)

    Lehnert, H.; Blauert, Jens; Pompetzki, W.

    1991-01-01

    In every-day listening the auditory event perceived by a listener is determined not only by the sound signal that a sound emits but also by a variety of environmental parameters. These parameters are the position, orientation and directional characteristics of the sound source, the listener's position and orientation, the geometrical and acoustical properties of surfaces which affect the sound field and the sound propagation properties of the surrounding fluid. A complete set of these parameters can be called an Acoustic Environment. If the auditory event perceived by a listener is manipulated in such a way that the listener is shifted acoustically into a different acoustic environment without moving himself physically, a Virtual Acoustic Environment has been created. Here, we deal with a special technique to set up nearly arbitrary Virtual Acoustic Environments, the Binaural Room Simulation. The purpose of the Binaural Room Simulation is to compute the binaural impulse response related to a virtual acoustic environment taking into account all parameters mentioned above. One possible way to describe a Virtual Acoustic Environment is the concept of the virtual sound sources. Each of the virtual sources emits a certain signal which is correlated but not necessarily identical with the signal emitted by the direct sound source. If source and receiver are non moving, the acoustic environment becomes a linear time-invariant system. Then, the Binaural Impulse Response from the source to a listener' s eardrums contains all relevant auditory information related to the Virtual Acoustic Environment. Listening into the simulated environment can easily be achieved by convolving the Binaural Impulse Response with dry signals and representing the results via headphones.

  4. Statistics of Natural Binaural Sounds

    PubMed Central

    Młynarski, Wiktor; Jost, Jürgen

    2014-01-01

    Binaural sound localization is usually considered a discrimination task, where interaural phase (IPD) and level (ILD) disparities at narrowly tuned frequency channels are utilized to identify a position of a sound source. In natural conditions however, binaural circuits are exposed to a stimulation by sound waves originating from multiple, often moving and overlapping sources. Therefore statistics of binaural cues depend on acoustic properties and the spatial configuration of the environment. Distribution of cues encountered naturally and their dependence on physical properties of an auditory scene have not been studied before. In the present work we analyzed statistics of naturally encountered binaural sounds. We performed binaural recordings of three auditory scenes with varying spatial configuration and analyzed empirical cue distributions from each scene. We have found that certain properties such as the spread of IPD distributions as well as an overall shape of ILD distributions do not vary strongly between different auditory scenes. Moreover, we found that ILD distributions vary much weaker across frequency channels and IPDs often attain much higher values, than can be predicted from head filtering properties. In order to understand the complexity of the binaural hearing task in the natural environment, sound waveforms were analyzed by performing Independent Component Analysis (ICA). Properties of learned basis functions indicate that in natural conditions soundwaves in each ear are predominantly generated by independent sources. This implies that the real-world sound localization must rely on mechanisms more complex than a mere cue extraction. PMID:25285658

  5. Advancing Binaural Cochlear Implant Technology

    PubMed Central

    McAlpine, David

    2015-01-01

    This special issue contains a collection of 13 papers highlighting the collaborative research and engineering project entitled Advancing Binaural Cochlear Implant Technology—ABCIT—as well as research spin-offs from the project. In this introductory editorial, a brief history of the project is provided, alongside an overview of the studies. PMID:26721929

  6. Dynamic binaural sound localization based on variations of interaural time delays and system rotations.

    PubMed

    Baumann, Claude; Rogers, Chris; Massen, Francis

    2015-08-01

    This work develops the mathematical model for a steerable binaural system that determines the instantaneous direction of a sound source in space. The model combines system angular speed and interaural time delays (ITDs) in a differential equation, which allows monitoring the change of source position in the binaural reference frame and therefore resolves the confusion about azimuth and elevation. The work includes the analysis of error propagation and presents results from a real-time application that was performed on a digital signal processing device. Theory and experiments demonstrate that the azimuthal angle to the sound source is accurately yielded in the case of horizontal rotations, whereas the elevation angle is estimated with large uncertainty. This paper also proves the equivalence of the ITD derivative and the Doppler shift appearing between the binaurally captured audio signals. The equation of this Doppler shift is applicable for any kind of motion. It shows that weak binaural pitch differences may represent an additional cue in localization of sound. Finally, the paper develops practical applications from this relationship, such as the synthesizing of binaural images of pure and complex tones emitted by a moving source, and the generation of multiple frequency images for binaural beat experiments. PMID:26328682

  7. Binaural Loudness Summation in the Hearing Impaired.

    ERIC Educational Resources Information Center

    Hawkins, David B.; And Others

    1987-01-01

    Binaural loudness summation was measured using three different paradigms with 10 normally hearing and 20 bilaterally symmetrical high-frequency sensorineural hearing loss subjects. Binaural summation increased with presentation level using the loudness matching procedure, with values in the 6-10 dB range. Summation decreased with level using the…

  8. Leak detection utilizing analog binaural (VLSI) techniques

    NASA Technical Reports Server (NTRS)

    Hartley, Frank T. (Inventor)

    1995-01-01

    A detection method and system utilizing silicon models of the traveling wave structure of the human cochlea to spatially and temporally locate a specific sound source in the presence of high noise pandemonium. The detection system combines two-dimensional stereausis representations, which are output by at least three VLSI binaural hearing chips, to generate a three-dimensional stereausis representation including both binaural and spectral information which is then used to locate the sound source.

  9. The impact of binaural beats on creativity

    PubMed Central

    Reedijk, Susan A.; Bolders, Anne; Hommel, Bernhard

    2013-01-01

    Human creativity relies on a multitude of cognitive processes, some of which are influenced by the neurotransmitter dopamine. This suggests that creativity could be enhanced by interventions that either modulate the production or transmission of dopamine directly, or affect dopamine-driven processes. In the current study we hypothesized that creativity can be influenced by means of binaural beats, an auditory illusion that is considered a form of cognitive entrainment that operates through stimulating neuronal phase locking. We aimed to investigate whether binaural beats affect creative performance at all, whether they affect divergent thinking, convergent thinking, or both, and whether possible effects may be mediated by the individual striatal dopamine level. Binaural beats were presented at alpha and gamma frequency. Participants completed a divergent and a convergent thinking task to assess two important functions of creativity, and filled out the Positive And Negative Affect Scale—mood State questionnaire (PANAS-S) and an affect grid to measure current mood. Dopamine levels in the striatum were estimated using spontaneous eye blink rates (EBRs). Results showed that binaural beats, regardless of the presented frequency, can affect divergent but not convergent thinking. Individuals with low EBRs mostly benefitted from alpha binaural beat stimulation, while individuals with high EBRs were unaffected or even impaired by both alpha and gamma binaural beats. This suggests that binaural beats, and possibly other forms of cognitive entrainment, are not suited for a one-size-fits-all approach, and that individual cognitive-control systems need to be taken into account when studying cognitive enhancement methods. PMID:24294202

  10. Comparing Binaural Pre-processing Strategies II

    PubMed Central

    Hu, Hongmei; Krawczyk-Becker, Martin; Marquardt, Daniel; Herzke, Tobias; Coleman, Graham; Adiloğlu, Kamil; Bomke, Katrin; Plotz, Karsten; Gerkmann, Timo; Doclo, Simon; Kollmeier, Birger; Hohmann, Volker; Dietz, Mathias

    2015-01-01

    Several binaural audio signal enhancement algorithms were evaluated with respect to their potential to improve speech intelligibility in noise for users of bilateral cochlear implants (CIs). 50% speech reception thresholds (SRT50) were assessed using an adaptive procedure in three distinct, realistic noise scenarios. All scenarios were highly nonstationary, complex, and included a significant amount of reverberation. Other aspects, such as the perfectly frontal target position, were idealized laboratory settings, allowing the algorithms to perform better than in corresponding real-world conditions. Eight bilaterally implanted CI users, wearing devices from three manufacturers, participated in the study. In all noise conditions, a substantial improvement in SRT50 compared to the unprocessed signal was observed for most of the algorithms tested, with the largest improvements generally provided by binaural minimum variance distortionless response (MVDR) beamforming algorithms. The largest overall improvement in speech intelligibility was achieved by an adaptive binaural MVDR in a spatially separated, single competing talker noise scenario. A no-pre-processing condition and adaptive differential microphones without a binaural link served as the two baseline conditions. SRT50 improvements provided by the binaural MVDR beamformers surpassed the performance of the adaptive differential microphones in most cases. Speech intelligibility improvements predicted by instrumental measures were shown to account for some but not all aspects of the perceptually obtained SRT50 improvements measured in bilaterally implanted CI users. PMID:26721921

  11. Binaural signal analysis of diffuse sound fields

    NASA Astrophysics Data System (ADS)

    Novo, Pedro A.

    2004-10-01

    The simulation and the binaural recording of sounds produced by large crowds and rain impact sounds has produced an unexpected result. The listeners have reported that the auditory events were mainly concentrated to the left and to right, although the sound sources were equally distributed around the listeners. A similar result was reported with binaural recordings of applause. The results of a binaural signal analysis suggest that the key aspect regarding the lateral position dominance of the auditory events is connected to the sections where the cross-correlation coefficient assumes negative values. A comparison between normalized and non-normalized cross-correlation function predictions indicates that the latter is a better predictor for the cases studied. An adaptation period of several seconds was reported by several listeners. It is suggested that this adaptation period is related to the variations of the cross-correlation, which only average out after, approximately 2 s. The binaural impulse responses of a concert hall at two different listener positions have been analyzed in the light of the previous findings. In particular the diffuse sound field buildup will be analyzed in detail. Implications for the auditory source width and listener envelopment will be discussed.

  12. Human cortical responses to slow and fast binaural beats reveal multiple mechanisms of binaural hearing.

    PubMed

    Ross, Bernhard; Miyazaki, Takahiro; Thompson, Jessica; Jamali, Shahab; Fujioka, Takako

    2014-10-15

    When two tones with slightly different frequencies are presented to both ears, they interact in the central auditory system and induce the sensation of a beating sound. At low difference frequencies, we perceive a single sound, which is moving across the head between the left and right ears. The percept changes to loudness fluctuation, roughness, and pitch with increasing beat rate. To examine the neural representations underlying these different perceptions, we recorded neuromagnetic cortical responses while participants listened to binaural beats at a continuously varying rate between 3 Hz and 60 Hz. Binaural beat responses were analyzed as neuromagnetic oscillations following the trajectory of the stimulus rate. Responses were largest in the 40-Hz gamma range and at low frequencies. Binaural beat responses at 3 Hz showed opposite polarity in the left and right auditory cortices. We suggest that this difference in polarity reflects the opponent neural population code for representing sound location. Binaural beats at any rate induced gamma oscillations. However, the responses were largest at 40-Hz stimulation. We propose that the neuromagnetic gamma oscillations reflect postsynaptic modulation that allows for precise timing of cortical neural firing. Systematic phase differences between bilateral responses suggest that separate sound representations of a sound object exist in the left and right auditory cortices. We conclude that binaural processing at the cortical level occurs with the same temporal acuity as monaural processing whereas the identification of sound location requires further interpretation and is limited by the rate of object representations. PMID:25008412

  13. Loudness enhancement - Monaural, binaural, and dichotic

    NASA Technical Reports Server (NTRS)

    Elmasian, R.; Galambos, R.

    1975-01-01

    When one tone burst (T) precedes another (S) by 100 msec, variations in the intensity of T systematically influence the loudness of S. When T is more intense than S, S is increased; and when T is less intense, S loudness is decreased. This occurs in monaural, binaural, and dichotic paradigms of signal presentation. When T and S are presented to the same ear (monaural or binaural), there is more enhancement with less intersubject variability than when they are presented to different ears (dichotic paradigm). Monaural enhancements as large as 30 dB can readily be demonstrated, but decrements rarely exceed 5 dB. Possible physiological mechanisms are discussed for this loudness enhancement, which apparently shares certain characteristics with time-order error, assimilation, and temporal partial masking experiments.

  14. A probabilistic model for binaural sound localization.

    PubMed

    Willert, Volker; Eggert, Julian; Adamy, Jürgen; Stahl, Raphael; Körner, Edgar

    2006-10-01

    This paper proposes a biologically inspired and technically implemented sound localization system to robustly estimate the position of a sound source in the frontal azimuthal half-plane. For localization, binaural cues are extracted using cochleagrams generated by a cochlear model that serve as input to the system. The basic idea of the model is to separately measure interaural time differences and interaural level differences for a number of frequencies and process these measurements as a whole. This leads to two-dimensional frequency versus time-delay representations of binaural cues, so-called activity maps. A probabilistic evaluation is presented to estimate the position of a sound source over time based on these activity maps. Learned reference maps for different azimuthal positions are integrated into the computation to gain time-dependent discrete conditional probabilities. At every timestep these probabilities are combined over frequencies and binaural cues to estimate the sound source position. In addition, they are propagated over time to improve position estimation. This leads to a system that is able to localize audible signals, for example human speech signals, even in reverberating environments. PMID:17036807

  15. Binaural Advantage for Younger and Older Adults with Normal Hearing

    ERIC Educational Resources Information Center

    Dubno, Judy R.; Ahlstrom, Jayne B.; Horwitz, Amy R.

    2008-01-01

    Purpose: Three experiments measured benefit of spatial separation, benefit of binaural listening, and masking-level differences (MLDs) to assess age-related differences in binaural advantage. Method: Participants were younger and older adults with normal hearing through 4.0 kHz. Experiment 1 compared spatial benefit with and without head shadow.…

  16. Monaural Congenital Deafness Affects Aural Dominance and Degrades Binaural Processing

    PubMed Central

    Tillein, Jochen; Hubka, Peter; Kral, Andrej

    2016-01-01

    Cortical development extensively depends on sensory experience. Effects of congenital monaural and binaural deafness on cortical aural dominance and representation of binaural cues were investigated in the present study. We used an animal model that precisely mimics the clinical scenario of unilateral cochlear implantation in an individual with single-sided congenital deafness. Multiunit responses in cortical field A1 to cochlear implant stimulation were studied in normal-hearing cats, bilaterally congenitally deaf cats (CDCs), and unilaterally deaf cats (uCDCs). Binaural deafness reduced cortical responsiveness and decreased response thresholds and dynamic range. In contrast to CDCs, in uCDCs, cortical responsiveness was not reduced, but hemispheric-specific reorganization of aural dominance and binaural interactions were observed. Deafness led to a substantial drop in binaural facilitation in CDCs and uCDCs, demonstrating the inevitable role of experience for a binaural benefit. Sensitivity to interaural time differences was more reduced in uCDCs than in CDCs, particularly at the hemisphere ipsilateral to the hearing ear. Compared with binaural deafness, unilateral hearing prevented nonspecific reduction in cortical responsiveness, but extensively reorganized aural dominance and binaural responses. The deaf ear remained coupled with the cortex in uCDCs, demonstrating a significant difference to deprivation amblyopia in the visual system. PMID:26803166

  17. Monaural Congenital Deafness Affects Aural Dominance and Degrades Binaural Processing.

    PubMed

    Tillein, Jochen; Hubka, Peter; Kral, Andrej

    2016-04-01

    Cortical development extensively depends on sensory experience. Effects of congenital monaural and binaural deafness on cortical aural dominance and representation of binaural cues were investigated in the present study. We used an animal model that precisely mimics the clinical scenario of unilateral cochlear implantation in an individual with single-sided congenital deafness. Multiunit responses in cortical field A1 to cochlear implant stimulation were studied in normal-hearing cats, bilaterally congenitally deaf cats (CDCs), and unilaterally deaf cats (uCDCs). Binaural deafness reduced cortical responsiveness and decreased response thresholds and dynamic range. In contrast to CDCs, in uCDCs, cortical responsiveness was not reduced, but hemispheric-specific reorganization of aural dominance and binaural interactions were observed. Deafness led to a substantial drop in binaural facilitation in CDCs and uCDCs, demonstrating the inevitable role of experience for a binaural benefit. Sensitivity to interaural time differences was more reduced in uCDCs than in CDCs, particularly at the hemisphere ipsilateral to the hearing ear. Compared with binaural deafness, unilateral hearing prevented nonspecific reduction in cortical responsiveness, but extensively reorganized aural dominance and binaural responses. The deaf ear remained coupled with the cortex in uCDCs, demonstrating a significant difference to deprivation amblyopia in the visual system. PMID:26803166

  18. Comparing Binaural Pre-processing Strategies III

    PubMed Central

    Warzybok, Anna; Ernst, Stephan M. A.

    2015-01-01

    A comprehensive evaluation of eight signal pre-processing strategies, including directional microphones, coherence filters, single-channel noise reduction, binaural beamformers, and their combinations, was undertaken with normal-hearing (NH) and hearing-impaired (HI) listeners. Speech reception thresholds (SRTs) were measured in three noise scenarios (multitalker babble, cafeteria noise, and single competing talker). Predictions of three common instrumental measures were compared with the general perceptual benefit caused by the algorithms. The individual SRTs measured without pre-processing and individual benefits were objectively estimated using the binaural speech intelligibility model. Ten listeners with NH and 12 HI listeners participated. The participants varied in age and pure-tone threshold levels. Although HI listeners required a better signal-to-noise ratio to obtain 50% intelligibility than listeners with NH, no differences in SRT benefit from the different algorithms were found between the two groups. With the exception of single-channel noise reduction, all algorithms showed an improvement in SRT of between 2.1 dB (in cafeteria noise) and 4.8 dB (in single competing talker condition). Model predictions with binaural speech intelligibility model explained 83% of the measured variance of the individual SRTs in the no pre-processing condition. Regarding the benefit from the algorithms, the instrumental measures were not able to predict the perceptual data in all tested noise conditions. The comparable benefit observed for both groups suggests a possible application of noise reduction schemes for listeners with different hearing status. Although the model can predict the individual SRTs without pre-processing, further development is necessary to predict the benefits obtained from the algorithms at an individual level. PMID:26721922

  19. Accuracy of pointing a binaural listening array.

    PubMed

    Letowski, T R; Ricard, G L; Kalb, J T; Mermagen, T J; Amrein, K M

    1997-12-01

    We measured the accuracy with which sounds heard over a binaural, end-fire array could be located when the angular separation of the array's two arms was varied. Each individual arm contained nine cardioid electret microphones, the responses of which were combined to produce a unidirectional, band-limited pattern of sensitivity. We assessed the desirable angular separation of these arms by measuring the accuracy with which listeners could point to the source of a target sound presented against high-level background noise. We employed array separations of 30 degrees, 45 degrees, and 60 degrees, and signal-to-noise ratios of +5, -5, and -15 dB. Pointing accuracy was best for a separation of 60 degrees; this performance was indistinguishable from pointing during unaided listening conditions. In addition, the processing of the array was modeled to depict the information that was available for localization. The model indicates that highly directional binaural arrays can be expected to support accurate localization of sources of sound only near the axis of the array. Wider enhanced listening angles may be possible if the forward coverage of the sensor system is made less directional and more similar to that of human listeners. PMID:9473975

  20. Comparing Binaural Pre-processing Strategies I

    PubMed Central

    Krawczyk-Becker, Martin; Marquardt, Daniel; Völker, Christoph; Hu, Hongmei; Herzke, Tobias; Coleman, Graham; Adiloğlu, Kamil; Ernst, Stephan M. A.; Gerkmann, Timo; Doclo, Simon; Kollmeier, Birger; Hohmann, Volker; Dietz, Mathias

    2015-01-01

    In a collaborative research project, several monaural and binaural noise reduction algorithms have been comprehensively evaluated. In this article, eight selected noise reduction algorithms were assessed using instrumental measures, with a focus on the instrumental evaluation of speech intelligibility. Four distinct, reverberant scenarios were created to reflect everyday listening situations: a stationary speech-shaped noise, a multitalker babble noise, a single interfering talker, and a realistic cafeteria noise. Three instrumental measures were employed to assess predicted speech intelligibility and predicted sound quality: the intelligibility-weighted signal-to-noise ratio, the short-time objective intelligibility measure, and the perceptual evaluation of speech quality. The results show substantial improvements in predicted speech intelligibility as well as sound quality for the proposed algorithms. The evaluated coherence-based noise reduction algorithm was able to provide improvements in predicted audio signal quality. For the tested single-channel noise reduction algorithm, improvements in intelligibility-weighted signal-to-noise ratio were observed in all but the nonstationary cafeteria ambient noise scenario. Binaural minimum variance distortionless response beamforming algorithms performed particularly well in all noise scenarios. PMID:26721920

  1. Loudness enhancement: Monaural, binaural and dichotic

    NASA Technical Reports Server (NTRS)

    Elmasian, R. O.; Galambos, R.

    1975-01-01

    It is shown that when one tone burst precedes another by 100 msec variations in the intensity of the first systematically influences the loudness of second. When the first burst is more intense than the second, the second is increased and when the first burst is less intense, the loudness of the second is decreased. This occurs in monaural, binaural and dichotic paradigms of signal presentation. Where both bursts are presented to the same ear there is more enhancement with less intersubject variability than when they are presented to different ears. Monaural enhancements as large as 30 db can readily be demonstrated, but decrements rarely exceed 5 db. Possible physiological mechanisms are discussed for this loudness enhancement, which apparently shares certain characteristics with time-order-error, assimilation, and temporal partial masking experiments.

  2. Binaural unmasking of frequency-following responses in rat amygdala.

    PubMed

    Du, Yi; Huang, Qiang; Wu, Xihong; Galbraith, Gary C; Li, Liang

    2009-03-01

    Survival in natural environments for small animals such as rats often depends on precise neural coding of life-threatening acoustic signals, and binaural unmasking of species-specific pain calls is especially critical. This study investigated how species-specific tail-pain chatter is represented in the rat amygdala, which receives afferents from both auditory thalamus and auditory association cortex, and whether the amygdaloid representation of the chatter can be binaurally unmasked. The results show that chatter with a fundamental frequency (F0) of 2.1 kHz was able to elicit salient phase-locked frequency-following responses (FFRs) in the lateral amygdala nucleus in anesthetized rats. FFRs to the F0 of binaurally presented chatter were sensitive to the interaural time difference (ITD), with the preference of ipsilateral-ear leading, as well as showing features of binaural inhibition. When interaurally correlated masking noises were added and ipsilateral chatter led contralateral chatter, introducing an ITD disparity between the chatter and masker significantly enhanced (unmasked) the FFRs. This binaural unmasking was further enhanced by chemically blocking excitatory glutamate receptors in the auditory association cortex. When the chatter was replaced by a harmonic tone complex with an F0 of 0.7 kHz, both the binaural-inhibition feature and the binaural unmasking were preserved only for the harmonic of 2.1 kHz but not the tone F0. These results suggest that both frequency-dependent ascending binaural modulations and cortical descending modulations of the precise auditory coding of the chatter in the amygdala are critical for processing life-threatening acoustic signals in noisy and even reverberant environments. PMID:19036862

  3. Spectral and binaural loudness summation for hearing-impaired listeners.

    PubMed

    Oetting, Dirk; Hohmann, Volker; Appell, Jens-E; Kollmeier, Birger; Ewert, Stephan D

    2016-05-01

    Sensorineural hearing loss typically results in a steepened loudness function and a reduced dynamic range from elevated thresholds to uncomfortably loud levels for narrowband and broadband signals. Restoring narrowband loudness perception for hearing-impaired (HI) listeners can lead to overly loud perception of broadband signals and it is unclear how binaural presentation affects loudness perception in this case. Here, loudness perception quantified by categorical loudness scaling for nine normal-hearing (NH) and ten HI listeners was compared for signals with different bandwidth and different spectral shape in monaural and in binaural conditions. For the HI listeners, frequency- and level-dependent amplification was used to match the narrowband monaural loudness functions of the NH listeners. The average loudness functions for NH and HI listeners showed good agreement for monaural broadband signals. However, HI listeners showed substantially greater loudness for binaural broadband signals than NH listeners: on average a 14.1 dB lower level was required to reach "very loud" (range 30.8 to -3.7 dB). Overall, with narrowband loudness compensation, a given binaural loudness for broadband signals above "medium loud" was reached at systematically lower levels for HI than for NH listeners. Such increased binaural loudness summation was not found for loudness categories below "medium loud" or for narrowband signals. Large individual variations in the increased loudness summation were observed and could not be explained by the audiogram or the narrowband loudness functions. PMID:27006003

  4. Binaural hearing in children using Gaussian enveloped and transposed tones.

    PubMed

    Ehlers, Erica; Kan, Alan; Winn, Matthew B; Stoelb, Corey; Litovsky, Ruth Y

    2016-04-01

    Children who use bilateral cochlear implants (BiCIs) show significantly poorer sound localization skills than their normal hearing (NH) peers. This difference has been attributed, in part, to the fact that cochlear implants (CIs) do not faithfully transmit interaural time differences (ITDs) and interaural level differences (ILDs), which are known to be important cues for sound localization. Interestingly, little is known about binaural sensitivity in NH children, in particular, with stimuli that constrain acoustic cues in a manner representative of CI processing. In order to better understand and evaluate binaural hearing in children with BiCIs, the authors first undertook a study on binaural sensitivity in NH children ages 8-10, and in adults. Experiments evaluated sound discrimination and lateralization using ITD and ILD cues, for stimuli with robust envelope cues, but poor representation of temporal fine structure. Stimuli were spondaic words, Gaussian-enveloped tone pulse trains (100 pulse-per-second), and transposed tones. Results showed that discrimination thresholds in children were adult-like (15-389 μs for ITDs and 0.5-6.0 dB for ILDs). However, lateralization based on the same binaural cues showed higher variability than seen in adults. Results are discussed in the context of factors that may be responsible for poor representation of binaural cues in bilaterally implanted children. PMID:27106319

  5. The effect of overlap-masking on binaural reverberant word intelligibility

    NASA Astrophysics Data System (ADS)

    Libbey, Brad; Rogers, Peter H.

    2004-11-01

    Reverberation interferes with the ability to understand speech in rooms. Overlap-masking explains this degradation by assuming reverberant phonemes endure in time and mask subsequent reverberant phonemes. Most listeners benefit from binaural listening when reverberation exists, indicating that the listener's binaural system processes the two channels to reduce the reverberation. This paper investigates the hypothesis that the binaural word intelligibility advantage found in reverberation is a result of binaural overlap-masking release with the reverberation acting as masking noise. The tests utilize phonetically balanced word lists (ANSI-S3.2 1989), that are presented diotically and binaurally with recorded reverberation and reverberation-like noise. A small room, 62 m3, reverberates the words. These are recorded using two microphones without additional noise sources. The reverberation-like noise is a modified form of these recordings and has a similar spectral content. It does not contain binaural localization cues due to a phase randomization procedure. Listening to the reverberant words binaurally improves the intelligibility by 6.0% over diotic listening. The binaural intelligibility advantage for reverberation-like noise is only 2.6%. This indicates that binaural overlap-masking release is insufficient to explain the entire binaural word intelligibility advantage in reverberation. .

  6. [Sound localization cues of binaural hearing].

    PubMed

    Paulus, E

    2003-04-01

    characteristics of the outer ears. Scientific findings further suggest that spectral patterns like peaks and notches may also be exploited monaurally, albeit an a priori-knowledge at the central-auditive level concerning the corresponding transfer functions and relevant real-world sounds is required. Binaural spectral cues are more likely to play a major role in localization. They are derived from another transfer function, the so-called Interaural Transfer Function (ITF), being the ratio of the ATFs at the two ears. The contributions of all these cues may sometimes not be enough to prevent the listener from opting for the wrong direction. But things can be eased by allowing head-movements: More than 60 years ago science reasoned that small head movements could provide the information necessary to resolve most of the ambiguities. Recent studies have proved that these findings have been accurate all along. PMID:12717598

  7. The effect of stimulus bandwidth on binaural loudness summation.

    PubMed

    Shao, Zhiyue; Mo, Fangshuo; Mao, Dongxing

    2015-09-01

    Binaural loudness summation is an important property of the human auditory system. This paper presents an experimental investigation of how binaural loudness summation varies with stimulus bandwidth. Loudness matches were obtained between dichotic stimuli, with interaural level differences (ILDs) of 2-12 dB, and diotic stimuli. The stimuli were noise bands with seven center frequencies and four bandwidths. Results showed that the loudness of dichotic stimuli increased nonlinearly with ILD, the increase being slightly less with broader bandwidths. There was a bandwidth-dependent difference between the listening tests results and the predictions of Moore and Glasberg's [(2007) J. Acoust. Soc. Am. 121, 1604-1612] loudness model. The size of the difference was, however, small. A characteristic function was derived describing how overall loudness depends on stimulus bandwidth and ILD. PMID:26428788

  8. Rate-Constrained Beamforming in Binaural Hearing Aids

    NASA Astrophysics Data System (ADS)

    Srinivasan, Sriram; den Brinker, Albertus C.

    2009-12-01

    Recently, hearing aid systems where the left and right ear devices collaborate with one another have received much attention. Apart from supporting natural binaural hearing, such systems hold great potential for improving the intelligibility of speech in the presence of noise through beamforming algorithms. Binaural beamforming for hearing aids requires an exchange of microphone signals between the two devices over a wireless link. This paper studies two problems: which signal to transmit from one ear to the other, and at what bit-rate. The first problem is relevant as modern hearing aids usually contain multiple microphones, and the optimal choice for the signal to be transmitted is not obvious. The second problem is relevant as the capacity of the wireless link is limited by stringent power consumption constraints imposed by the limited battery life of hearing aids.

  9. The Effect of Asymmetrical Signal Degradation on Binaural Speech Recognition in Children and Adults.

    ERIC Educational Resources Information Center

    Rothpletz, Ann M.; Tharpe, Anne Marie; Grantham, D. Wesley

    2004-01-01

    To determine the effect of asymmetrical signal degradation on binaural speech recognition, 28 children and 14 adults were administered a sentence recognition task amidst multitalker babble. There were 3 listening conditions: (a) monaural, with mild degradation in 1 ear; (b) binaural, with mild degradation in both ears (symmetric degradation); and…

  10. Role of binaural hearing in speech intelligibility and spatial release from masking using vocoded speech.

    PubMed

    Garadat, Soha N; Litovsky, Ruth Y; Yu, Gongqiang; Zeng, Fan-Gang

    2009-11-01

    A cochlear implant vocoder was used to evaluate relative contributions of spectral and binaural temporal fine-structure cues to speech intelligibility. In Study I, stimuli were vocoded, and then convolved through head related transfer functions (HRTFs) to remove speech temporal fine structure but preserve the binaural temporal fine-structure cues. In Study II, the order of processing was reversed to remove both speech and binaural temporal fine-structure cues. Speech reception thresholds (SRTs) were measured adaptively in quiet, and with interfering speech, for unprocessed and vocoded speech (16, 8, and 4 frequency bands), under binaural or monaural (right-ear) conditions. Under binaural conditions, as the number of bands decreased, SRTs increased. With decreasing number of frequency bands, greater benefit from spatial separation of target and interferer was observed, especially in the 8-band condition. The present results demonstrate a strong role of the binaural cues in spectrally degraded speech, when the target and interfering speech are more likely to be confused. The nearly normal binaural benefits under present simulation conditions and the lack of order of processing effect further suggest that preservation of binaural cues is likely to improve performance in bilaterally implanted recipients. PMID:19894832

  11. Binaural Interaction in Specific Language Impairment: An Auditory Evoked Potential Study

    ERIC Educational Resources Information Center

    Clarke, Elaine M; Adams, Catherine

    2007-01-01

    The aim of the study was to examine whether auditory binaural interaction, defined as any difference between binaurally evoked responses and the sum of monaurally evoked responses, which is thought to index functions involved in the localization and detection of signals in background noise, is atypical in a group of children with specific language…

  12. Unilateral spectral and temporal compression reduces binaural fusion for normal hearing listeners with cochlear implant simulations

    PubMed Central

    Aronoff, Justin M.; Shayman, Corey; Prasad, Akila; Suneel, Deepa; Stelmach, Julia

    2015-01-01

    Patients with single sided deafness have recently begun receiving cochlear implants in their deaf ear. These patients gain a significant benefit from having a cochlear implant. However, despite this benefit, they are considerably slower to develop binaural abilities such as summation compared to bilateral cochlear implant patients. This suggests that these patients have difficulty fusing electric and acoustic signals. Although this may reflect inherent differences between electric and acoustic stimulation, it may also reflect properties of the processor and fitting system, which result in spectral and temporal compression. To examine the possibility that unilateral spectral and temporal compression can adversely affect binaural fusion, this study tested normal hearing listeners’ binaural fusion through the use of vocoded speech with unilateral spectral and temporal compression. The results indicate that unilateral spectral and temporal compression can hinder binaural fusion and thus may adversely affect binaural abilities in patients with single sided deafness who use a cochlear implant in their deaf ear. PMID:25549574

  13. A Comparison of Two Objective Measures of Binaural Processing

    PubMed Central

    Undurraga, Jaime A.; Marquardt, Torsten; McAlpine, David

    2015-01-01

    There has been continued interest in clinical objective measures of binaural processing. One commonly proposed measure is the binaural interaction component (BIC), which is obtained typically by recording auditory brainstem responses (ABRs)—the BIC reflects the difference between the binaural ABR and the sum of the monaural ABRs (i.e., binaural − (left + right)). We have recently developed an alternative, direct measure of sensitivity to interaural time differences, namely, a following response to modulations in interaural phase difference (the interaural phase modulation following response; IPM-FR). To obtain this measure, an ongoing diotically amplitude-modulated signal is presented, and the interaural phase difference of the carrier is switched periodically at minima in the modulation cycle. Such periodic modulations to interaural phase difference can evoke a steady state following response. BIC and IPM-FR measurements were compared from 10 normal-hearing subjects using a 16-channel electroencephalographic system. Both ABRs and IPM-FRs were observed most clearly from similar electrode locations—differential recordings taken from electrodes near the ear (e.g., mastoid) in reference to a vertex electrode (Cz). Although all subjects displayed clear ABRs, the BIC was not reliably observed. In contrast, the IPM-FR typically elicited a robust and significant response. In addition, the IPM-FR measure required a considerably shorter recording session. As the IPM-FR magnitude varied with interaural phase difference modulation depth, it could potentially serve as a correlate of perceptual salience. Overall, the IPM-FR appears a more suitable clinical measure than the BIC. PMID:26721925

  14. A Comparison of Two Objective Measures of Binaural Processing: The Interaural Phase Modulation Following Response and the Binaural Interaction Component.

    PubMed

    Haywood, Nicholas R; Undurraga, Jaime A; Marquardt, Torsten; McAlpine, David

    2015-01-01

    There has been continued interest in clinical objective measures of binaural processing. One commonly proposed measure is the binaural interaction component (BIC), which is obtained typically by recording auditory brainstem responses (ABRs)-the BIC reflects the difference between the binaural ABR and the sum of the monaural ABRs (i.e., binaural - (left + right)). We have recently developed an alternative, direct measure of sensitivity to interaural time differences, namely, a following response to modulations in interaural phase difference (the interaural phase modulation following response; IPM-FR). To obtain this measure, an ongoing diotically amplitude-modulated signal is presented, and the interaural phase difference of the carrier is switched periodically at minima in the modulation cycle. Such periodic modulations to interaural phase difference can evoke a steady state following response. BIC and IPM-FR measurements were compared from 10 normal-hearing subjects using a 16-channel electroencephalographic system. Both ABRs and IPM-FRs were observed most clearly from similar electrode locations-differential recordings taken from electrodes near the ear (e.g., mastoid) in reference to a vertex electrode (Cz). Although all subjects displayed clear ABRs, the BIC was not reliably observed. In contrast, the IPM-FR typically elicited a robust and significant response. In addition, the IPM-FR measure required a considerably shorter recording session. As the IPM-FR magnitude varied with interaural phase difference modulation depth, it could potentially serve as a correlate of perceptual salience. Overall, the IPM-FR appears a more suitable clinical measure than the BIC. PMID:26721925

  15. A new perspective on binaural integration using response time methodology: super capacity revealed in conditions of binaural masking release

    PubMed Central

    Lentz, Jennifer J.; He, Yuan; Townsend, James T.

    2014-01-01

    This study applied reaction-time based methods to assess the workload capacity of binaural integration by comparing reaction time (RT) distributions for monaural and binaural tone-in-noise detection tasks. In the diotic contexts, an identical tone + noise stimulus was presented to each ear. In the dichotic contexts, an identical noise was presented to each ear, but the tone was presented to one of the ears 180° out of phase with respect to the other ear. Accuracy-based measurements have demonstrated a much lower signal detection threshold for the dichotic vs. the diotic conditions, but accuracy-based techniques do not allow for assessment of system dynamics or resource allocation across time. Further, RTs allow comparisons between these conditions at the same signal-to-noise ratio. Here, we apply a reaction-time based capacity coefficient, which provides an index of workload efficiency and quantifies the resource allocations for single ear vs. two ear presentations. We demonstrate that the release from masking generated by the addition of an identical stimulus to one ear is limited-to-unlimited capacity (efficiency typically less than 1), consistent with less gain than would be expected by probability summation. However, the dichotic presentation leads to a significant increase in workload capacity (increased efficiency)—most specifically at lower signal-to-noise ratios. These experimental results provide further evidence that configural processing plays a critical role in binaural masking release, and that these mechanisms may operate more strongly when the signal stimulus is difficult to detect, albeit still with nearly 100% accuracy. PMID:25202254

  16. A new perspective on binaural integration using response time methodology: super capacity revealed in conditions of binaural masking release.

    PubMed

    Lentz, Jennifer J; He, Yuan; Townsend, James T

    2014-01-01

    This study applied reaction-time based methods to assess the workload capacity of binaural integration by comparing reaction time (RT) distributions for monaural and binaural tone-in-noise detection tasks. In the diotic contexts, an identical tone + noise stimulus was presented to each ear. In the dichotic contexts, an identical noise was presented to each ear, but the tone was presented to one of the ears 180° out of phase with respect to the other ear. Accuracy-based measurements have demonstrated a much lower signal detection threshold for the dichotic vs. the diotic conditions, but accuracy-based techniques do not allow for assessment of system dynamics or resource allocation across time. Further, RTs allow comparisons between these conditions at the same signal-to-noise ratio. Here, we apply a reaction-time based capacity coefficient, which provides an index of workload efficiency and quantifies the resource allocations for single ear vs. two ear presentations. We demonstrate that the release from masking generated by the addition of an identical stimulus to one ear is limited-to-unlimited capacity (efficiency typically less than 1), consistent with less gain than would be expected by probability summation. However, the dichotic presentation leads to a significant increase in workload capacity (increased efficiency)-most specifically at lower signal-to-noise ratios. These experimental results provide further evidence that configural processing plays a critical role in binaural masking release, and that these mechanisms may operate more strongly when the signal stimulus is difficult to detect, albeit still with nearly 100% accuracy. PMID:25202254

  17. Binaural speech discrimination under noise in hearing-impaired listeners

    NASA Technical Reports Server (NTRS)

    Kumar, K. V.; Rao, A. B.

    1988-01-01

    This paper presents the results of an assessment of speech discrimination by hearing-impaired listeners (sensori-neural, conductive, and mixed groups) under binaural free-field listening in the presence of background noise. Subjects with pure-tone thresholds greater than 20 dB in 0.5, 1.0 and 2.0 kHz were presented with a version of the W-22 list of phonetically balanced words under three conditions: (1) 'quiet', with the chamber noise below 28 dB and speech at 60 dB; (2) at a constant S/N ratio of +10 dB, and with a background white noise at 70 dB; and (3) same as condition (2), but with the background noise at 80 dB. The mean speech discrimination scores decreased significantly with noise in all groups. However, the decrease in binaural speech discrimination scores with an increase in hearing impairment was less for material presented under the noise conditions than for the material presented in quiet.

  18. Modeling the utility of binaural cues for underwater sound localization.

    PubMed

    Schneider, Jennifer N; Lloyd, David R; Banks, Patchouly N; Mercado, Eduardo

    2014-06-01

    The binaural cues used by terrestrial animals for sound localization in azimuth may not always suffice for accurate sound localization underwater. The purpose of this research was to examine the theoretical limits of interaural timing and level differences available underwater using computational and physical models. A paired-hydrophone system was used to record sounds transmitted underwater and recordings were analyzed using neural networks calibrated to reflect the auditory capabilities of terrestrial mammals. Estimates of source direction based on temporal differences were most accurate for frequencies between 0.5 and 1.75 kHz, with greater resolution toward the midline (2°), and lower resolution toward the periphery (9°). Level cues also changed systematically with source azimuth, even at lower frequencies than expected from theoretical calculations, suggesting that binaural mechanical coupling (e.g., through bone conduction) might, in principle, facilitate underwater sound localization. Overall, the relatively limited ability of the model to estimate source position using temporal and level difference cues underwater suggests that animals such as whales may use additional cues to accurately localize conspecifics and predators at long distances. PMID:24727491

  19. Binaural cues provide for a release from informational masking.

    PubMed

    Tolnai, Sandra; Dolležal, Lena-Vanessa; Klump, Georg M

    2015-10-01

    Informational masking (IM) describes the insensitivity of detecting a change in sound features in a complex acoustical environment when such a change could easily be detected in the absence of distracting sounds. IM occurs because of the similarity between deviant sound and distracting sounds (so-called similarity-based IM) and/or stimulus uncertainty stemming from trial-to-trial variability (so-called uncertainty-based IM). IM can be abolished if similarity-based or uncertainty-based IM are minimized. Here, we modulated similarity-based IM using binaural cues. Standard/deviant tones and distracting tones were presented sequentially, and level-increment thresholds were measured. Deviant tones differed from standard tones by a higher sound level. Distracting tones covered a wide range of levels. Standard/deviant tones and distracting tones were characterized by their interaural time difference (ITD), interaural level difference (ILD), or both ITD and ILD. The larger the ITD or ILD was, the better similarity-based IM was overcome. If both interaural differences were applied to standard/deviant tones, the release from IM was larger than when either interaural difference was used. The results show that binaural cues are potent cues to abolish similarity-based IM and that the auditory system makes use of multiple available cues. PMID:26413722

  20. Optimal source distribution for binaural synthesis over loudspeakers

    NASA Astrophysics Data System (ADS)

    Takeuchi, Takashi; Nelson, Philip A.

    2002-12-01

    When binaural sound signals are presented with loudspeakers, the system inversion involved gives rise to a number of problems such as a loss of dynamic range and a lack of robustness to small errors and room reflections. The amplification required by the system inversion results in loss of dynamic range. The control performance of such a system deteriorates severely due to small errors resulting from, e.g., misalignment of the system and individual differences in the head related transfer functions at certain frequencies. The required large sound radiation results in severe reflection which also reduces the control performance. A method of overcoming these fundamental problems is proposed in this paper. A conceptual monopole transducer is introduced whose position varies continuously as frequency varies. This gives a minimum processing requirement of the binaural signals for the control to be achieved and all the above problems either disappear or are minimized. The inverse filters have flat amplitude response and the reproduced sound is not colored even outside the relatively large ``sweet area.'' A number of practical solutions are suggested for the realization of such optimally distributed transducers. One of them is a discretization that enables the use of conventional transducer units.

  1. Binaural release from masking with single- and multi-electrode stimulation in children with cochlear implants.

    PubMed

    Todd, Ann E; Goupell, Matthew J; Litovsky, Ruth Y

    2016-07-01

    Cochlear implants (CIs) provide children with access to speech information from a young age. Despite bilateral cochlear implantation becoming common, use of spatial cues in free field is smaller than in normal-hearing children. Clinically fit CIs are not synchronized across the ears; thus binaural experiments must utilize research processors that can control binaural cues with precision. Research to date has used single pairs of electrodes, which is insufficient for representing speech. Little is known about how children with bilateral CIs process binaural information with multi-electrode stimulation. Toward the goal of improving binaural unmasking of speech, this study evaluated binaural unmasking with multi- and single-electrode stimulation. Results showed that performance with multi-electrode stimulation was similar to the best performance with single-electrode stimulation. This was similar to the pattern of performance shown by normal-hearing adults when presented an acoustic CI simulation. Diotic and dichotic signal detection thresholds of the children with CIs were similar to those of normal-hearing children listening to a CI simulation. The magnitude of binaural unmasking was not related to whether the children with CIs had good interaural time difference sensitivity. Results support the potential for benefits from binaural hearing and speech unmasking in children with bilateral CIs. PMID:27475132

  2. Binaural loudness summation for speech presented via earphones and loudspeaker with and without visual cuesa)

    PubMed Central

    Epstein, Michael; Florentine, Mary

    2012-01-01

    Preliminary data [M. Epstein and M. Florentine, Ear. Hear. 30, 234–237 (2009)] obtained using speech stimuli from a visually present talker heard via loudspeakers in a sound-attenuating chamber indicate little difference in loudness when listening with one or two ears (i.e., significantly reduced binaural loudness summation, BLS), which is known as “binaural loudness constancy.” These data challenge current understanding drawn from laboratory measurements that indicate a tone presented binaurally is louder than the same tone presented monaurally. Twelve normal listeners were presented recorded spondees, monaurally and binaurally across a wide range of levels via earphones and a loudspeaker with and without visual cues. Statistical analyses of binaural-to-monaural ratios of magnitude estimates indicate that the amount of BLS is significantly less for speech presented via a loudspeaker with visual cues than for stimuli with any other combination of test parameters (i.e., speech presented via earphones or a loudspeaker without visual cues, and speech presented via earphones with visual cues). These results indicate that the loudness of a visually present talker in daily environments is little affected by switching between binaural and monaural listening. This supports the phenomenon of binaural loudness constancy and underscores the importance of ecological validity in loudness research. PMID:22559371

  3. Effects of binaural decorrelation on neural and behavioral processing of interaural level differences in the barn owl (Tyto alba).

    PubMed

    Egnor, S E

    2001-10-01

    The effect of binaural decorrelation on the processing of interaural level difference cues in the barn owl (Tyto alba) was examined behaviorally and electrophysiologically. The electrophysiology experiment measured the effect of variations in binaural correlation on the first stage of interaural level difference encoding in the central nervous system. The responses of single neurons in the posterior part of the ventral nucleus of the lateral lemniscus were recorded to stimulation with binaurally correlated and binaurally uncorrelated noise. No significant differences in interaural level difference sensitivity were found between conditions. Neurons in the posterior part of the ventral nucleus of the lateral lemniscus encode the interaural level difference of binaurally correlated and binaurally uncorrelated noise with equal accuracy and precision. This nucleus therefore supplies higher auditory centers with an undegraded interaural level difference signal for sound stimuli that lack a coherent interaural time difference. The behavioral experiment measured auditory saccades in response to interaural level differences presented in binaurally correlated and binaurally uncorrelated noise. The precision and accuracy of sound localization based on interaural level difference was reduced but not eliminated for binaurally uncorrelated signals. The observation that barn owls continue to vary auditory saccades with the interaural level difference of binaurally uncorrelated stimuli suggests that neurons that drive head saccades can be activated by incomplete auditory spatial information. PMID:11763957

  4. Cortical representation of the combination of monaural and binaural unmasking.

    PubMed

    Uppenkamp, Stefan; Uhlig, Christian H; Verhey, Jesko L

    2013-01-01

    The audibility of a target tone is improved by introducing either -amplitude modulations that are coherent across different frequency channels of the masker (comodulation masking release, CMR) or interaural phase differences that are -different for target and masker (binaural masking-level difference, BMLD). Although the two effects are likely to be based on different processing strategies, they both result in improved figure-background decomposition for a target-in-noise situation. In this study, we analyzed the combination of CMR and BMLD for a -target tone in a masker with six 48-Hz-wide noise bands, distributed over a wide frequency range from 216 Hz to 2.78 kHz. Psychoacoustical detection thresholds for the tones in noise were determined for two masker conditions (comodulated or unmodulated bands) and two interaural phase differences of the target tone (0 or 180°). The mean results indicate that the effects of unmasking add independently. The lowest thresholds are found for the dichotic signal embedded in a -modulated masker with an overall threshold difference of about 16 dB compared to the -unmodulated condition with no binaural cues. Based on the psychoacoustic results, a set of 12 signal-masker configurations was selected individually to explore the representation of the audibility of the test tone in brain activation maps by means of auditory functional MR imaging. The comparison of the results for the combination of CMR and BMLD with the results for the separate effects indicates a large overlap of the activated brain regions, where a largely extended area is activated, covering primary auditory cortex and adjacent regions. The result is in agreement with previous fMRI studies on auditory masking, identifying specific regions in the auditory cortex representing a change of the audibility of a target tone in a noise masker, irrespective of the overall sound pressure level of the stimulus. PMID:23716250

  5. A high-density EEG investigation into steady state binaural beat stimulation.

    PubMed

    Goodin, Peter; Ciorciari, Joseph; Baker, Kate; Carey, Anne-Marie; Carrey, Anne-Marie; Harper, Michelle; Kaufman, Jordy

    2012-01-01

    Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes including vigilance and brainwave entrainment. Some personality traits measured by the NEO Five Factor Model have been found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz) or Beta (16 Hz) frequency bands while undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period. Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the two bands examined and that certain personality traits were not more susceptible than others. PMID:22496862

  6. A High-Density EEG Investigation into Steady State Binaural Beat Stimulation

    PubMed Central

    Goodin, Peter; Ciorciari, Joseph; Baker, Kate; Carrey, Anne-Marie; Harper, Michelle; Kaufman, Jordy

    2012-01-01

    Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes including vigilance and brainwave entrainment. Some personality traits measured by the NEO Five Factor Model have been found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz) or Beta (16 Hz) frequency bands while undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period. Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the two bands examined and that certain personality traits were not more susceptible than others. PMID:22496862

  7. Analog Binaural Circuits for Detecting and Locating Leaks

    NASA Technical Reports Server (NTRS)

    Hartley, Frank T.

    2003-01-01

    Very-large-scale integrated (VLSI) analog binaural signal-processing circuits have been proposed for use in detecting and locating leaks that emit noise in the ultrasonic frequency range. These circuits would be designed to function even in the presence of intense lower-frequency background noise that could include sounds associated with flow and pumping. Each of the proposed circuits would include the approximate electronic equivalent of a right and a left cochlea plus correlator circuits. A pair of transducers (microphones or accelerometers), corresponding to right and left ears, would provide the inputs to their respective cochleas from different locations (e.g., from different positions along a pipe). The correlation circuits plus some additional external circuits would determine the difference between the times of arrival of a common leak sound at the two transducers. Then the distance along the pipe from either transducer to the leak could be estimated from the time difference and the speed of sound along the pipe. If three or more pairs of transducers and cochlear/correlator circuits were available and could suitably be positioned, it should be possible to locate a leak in three dimensions by use of sound propagating through air.

  8. Low-Frequency Envelope Sensitivity Produces Asymmetric Binaural Tuning Curves

    PubMed Central

    Agapiou, John P.; McAlpine, David

    2008-01-01

    Neurons in the auditory midbrain are sensitive to differences in the timing of sounds at the two ears—an important sound localization cue. We used broadband noise stimuli to investigate the interaural-delay sensitivity of low-frequency neurons in two midbrain nuclei: the inferior colliculus (IC) and the dorsal nucleus of the lateral lemniscus. Noise-delay functions showed asymmetries not predicted from a linear dependence on interaural correlation: a stretching along the firing-rate dimension (rate asymmetry), and a skewing along the interaural-delay dimension (delay asymmetry). These asymmetries were produced by an envelope-sensitive component to the response that could not entirely be accounted for by monaural or binaural nonlinearities, instead indicating an enhancement of envelope sensitivity at or after the level of the superior olivary complex. In IC, the skew-like asymmetry was consistent with intermediate-type responses produced by the convergence of ipsilateral peak-type inputs and contralateral trough-type inputs. This suggests a stereotyped pattern of input to the IC. In the course of this analysis, we were also able to determine the contribution of time and phase components to neurons' internal delays. These findings have important consequences for the neural representation of interaural timing differences and interaural correlation—cues critical to the perception of acoustic space. PMID:18753329

  9. Subjective diffuseness of music signals convolved with binaural impulse responses

    NASA Astrophysics Data System (ADS)

    Shimokura, Ryota; Tronchin, Lamberto; Cocchi, Alessandro; Soeta, Yoshiharu

    2011-07-01

    The spatial impression of sound in a hall can be quantified using sound field factors such as the interaural cross-correlation coefficient (IACC) calculated from binaural impulse response (BIR), henceforth denoted by IACC IR. The subjective diffuseness for the listener is a spatial attribute which depends on factors associated both with the source signal and with the actual sound field, and is quantified using the IACC of the signal received by the listener, henceforth denoted by IACC SR. Therefore, the subjective diffuseness in a given hall may change with the music. The aims of this study are to estimate the IACC SR from the IACC IR and the factors, which is obtained from autocorrelation function (ACF) of music signal, and to evaluate the subjective diffuseness by these factors. First, the relationship between the IACC IR and IACC SR was investigated. Second, subjective diffuseness was measured by a psycho-acoustical experiment. As a result, the IACC SR could be estimated from the IACC IR of the BIR and the effective duration ( τe) from the ACF of music signal. It was found that the effects of BIRs on subjective diffuseness could be evaluated by IACC IR for almost all subjects, while the effects of music signals could be evaluated by the τe and the width of the peak at τ=0 ( Wϕ(0) ) of the ACF.

  10. Binaural masking level differences in actual and simulated bilateral cochlear implant listeners

    PubMed Central

    Lu, Thomas; Litovsky, Ruth; Zeng, Fan-Gang

    2010-01-01

    At present commercially available bilateral cochlear implants (CIs) improve their users’ speech understanding in noise but they employ two independent speech processors that cannot provide accurate and appropriate interaural level and time differences as seen binaurally in normal hearing (NH) listeners. Previous work suggests that binaural cues are accessible to bilateral CI users when presented to single pairs of pitch-matched electrodes, but the scope was limited and the mechanisms remained unclear. In this study, binaural masking level differences (BMLDs) were measured in five bilateral Nucleus-24 CI users over multiple pairs of pitch-matched electrodes. Average BMLD was 4.6±4.9 dB, but large individual variability prevented significance (p=0.09). Considering just the 125 Hz condition, as in previous work, phase (N0S0 vs N0Sπ) and electrode effects were significant. Compared with simulated bilateral CI users, actual bilateral CI users had proportionally higher thresholds for N0Sπ than N0S0. Together the present results suggest that the performance gap in BMLDs between CI and NH listeners is not due to a lack of sufficient acoustic cues in the temporal envelope domain but to a true binaural deficit related to a central mechanism in deprived binaural processing. PMID:20329848

  11. An evaluation of the performance of two binaural beamformers in complex and dynamic multitalker environments

    PubMed Central

    Best, Virginia; Mejia, Jorge; Freeston, Katrina; van Hoesel, Richard J.; Dillon, Harvey

    2016-01-01

    Objective Binaural beamformers are super-directional hearing aids created by combining microphone outputs from each side of the head. While they offer substantial improvements in SNR over conventional directional hearing aids, the benefits (and possible limitations) of these devices in realistic, complex listening situations have not yet been fully explored. In this study we evaluated the performance of two experimental binaural beamformers. Design Testing was carried out using a horizontal loudspeaker array. Background noise was created using recorded conversations. Performance measures included speech intelligibility, localisation in noise, acceptable noise level, subjective ratings, and a novel dynamic speech intelligibility measure. Study sample Participants were 27 listeners with bilateral hearing loss, fitted with BTE prototypes that could be switched between conventional directional or binaural beamformer microphone modes. Results Relative to the conventional directional microphones, both binaural beamformer modes were generally superior for tasks involving fixed frontal targets, but not always for situations involving dynamic target locations. Conclusions Binaural beamformers show promise for enhancing listening in complex situations when the location of the source of interest is predictable. PMID:26140298

  12. Modeling the effects of a single reflection on binaural speech intelligibility.

    PubMed

    Rennies, Jan; Warzybok, Anna; Brand, Thomas; Kollmeier, Birger

    2014-03-01

    Recently the influence of delay and azimuth of a single speech reflection on speech reception thresholds (SRTs) was systematically investigated using frontal, diffuse, and lateral noise [Warzybok et al. (2013). J. Acoust. Soc. Am. 133, 269-282]. The experiments showed that the benefit of an early reflection was independent of its azimuth and mostly independent of noise type, but that the detrimental effect of a late reflection depended on its direction relative to the noise. This study tests if different extensions of a binaural speech intelligibility model can predict these data. The extensions differ in the order in which binaural processing and temporal integration of early reflections take place. Models employing a correction for the detrimental effects of reverberation on speech intelligibility after performing the binaural processing predict SRTs in symmetric masking conditions (frontal, diffuse), but cannot predict the measured interaction of temporal and spatial integration. In contrast, a model extension accounting for the distinction between useful and detrimental reflections before the binaural processing stage predicts the data with an overall R(2) of 0.95. This indicates that any model framework predicting speech intelligibility in rooms should incorporate an interaction between binaural and temporal integration of reflections at a comparatively early stage. PMID:24606290

  13. Extracting binaural information from simultaneous targets and distractors: Effects of amplitude modulation and asynchronous envelopes

    PubMed Central

    Stellmack, Mark A.; Byrne, Andrew J.; Viemeister, Neal F.

    2010-01-01

    When different components of a stimulus carry different binaural information, processing of binaural information in a target component is often affected. The present experiments examine whether such interference is affected by amplitude modulation and the relative phase of modulation of the target and distractors. In all experiments, listeners attempted to discriminate interaural time differences of a target stimulus in the presence of distractor stimuli with ITD=0. In Experiment 1, modulation of the distractors but not the target reduced interference between components. In Experiment 2, synthesized musical notes exhibited little binaural interference when there were slight asynchronies between different streams of notes (31 or 62 ms). The remaining experiments suggested that the reduction in binaural interference in the previous experiments was due neither to the complex spectra of the synthesized notes nor to greater detectability of the target in the presence of modulated distractors. These data suggest that this interference is reduced when components are modulated in ways that result in the target appearing briefly in isolation, not because of segregation cues. These data also suggest that modulation and asynchronies between modulators that might be encountered in real-world listening situations are adequate to reduce binaural interference to inconsequential levels. PMID:20815459

  14. Binaural Benefit with and without a Bilateral Spectral Mismatch in Acoustic Simulations of Cochlear Implant Processing

    PubMed Central

    Yoon, Yang-soo; Shin, You-Ree; Fu, Qian-Jie

    2012-01-01

    Objectives This study investigated whether a spectral mismatch across ears influences the benefit of redundancy, squelch, and head shadow differently in speech perception using acoustic simulation of bilateral cochlear implant (CI) processing. Design Ten normal hearing subjects participated in the study, and acoustic simulations of CIs were used to test these subjects. Sentence recognition, presented unilaterally and bilaterally, was measured at +5 dB and +10 dB signal-to-noise ratios (SNRs) with bilaterally matched and mismatched conditions. Unilateral and bilateral CIs were simulated using 8-channel sine-wave vocoders. Binaural spectral mismatch was introduced by changing the relative simulated insertion depths across ears. Subjects were tested while listening with headphones; head-related transfer functions were applied before the vocoder processing to preserve natural interaural level and time differences. Results For both SNRs, greater and more consistent binaural benefit of squelch and redundancy occurred for the matched condition while binaural interference of squelch and redundancy occurred for the mismatched condition. However, significant binaural benefit of head shadow existed irrespective of spectral mismatches and SNRs. Conclusions The results suggest that bilateral spectral mismatch may have a negative impact on the binaural benefit of squelch and redundancy for bilateral CI users. The results also suggest that clinical mapping should be carefully administrated for bilateral CI users to minimize the difference in spectral patterns between the two CIs. PMID:22968427

  15. Dual-microphone and binaural noise reduction techniques for improved speech intelligibility by hearing aid users

    NASA Astrophysics Data System (ADS)

    Yousefian Jazi, Nima

    Spatial filtering and directional discrimination has been shown to be an effective pre-processing approach for noise reduction in microphone array systems. In dual-microphone hearing aids, fixed and adaptive beamforming techniques are the most common solutions for enhancing the desired speech and rejecting unwanted signals captured by the microphones. In fact, beamformers are widely utilized in systems where spatial properties of target source (usually in front of the listener) is assumed to be known. In this dissertation, some dual-microphone coherence-based speech enhancement techniques applicable to hearing aids are proposed. All proposed algorithms operate in the frequency domain and (like traditional beamforming techniques) are purely based on the spatial properties of the desired speech source and does not require any knowledge of noise statistics for calculating the noise reduction filter. This benefit gives our algorithms the ability to address adverse noise conditions, such as situations where interfering talker(s) speaks simultaneously with the target speaker. In such cases, the (adaptive) beamformers lose their effectiveness in suppressing interference, since the noise channel (reference) cannot be built and updated accordingly. This difference is the main advantage of the proposed techniques in the dissertation over traditional adaptive beamformers. Furthermore, since the suggested algorithms are independent of noise estimation, they offer significant improvement in scenarios that the power level of interfering sources are much more than that of target speech. The dissertation also shows the premise behind the proposed algorithms can be extended and employed to binaural hearing aids. The main purpose of the investigated techniques is to enhance the intelligibility level of speech, measured through subjective listening tests with normal hearing and cochlear implant listeners. However, the improvement in quality of the output speech achieved by the

  16. Eliminating the Attentional Blink through Binaural Beats: A Case for Tailored Cognitive Enhancement

    PubMed Central

    Reedijk, Susan A.; Bolders, Anne; Colzato, Lorenza S.; Hommel, Bernhard

    2015-01-01

    Enhancing human cognitive performance is a topic that continues to spark scientific interest. Studies into cognitive-enhancement techniques often fail to take inter-individual differences into account, however, which leads to underestimation of the effectiveness of these techniques. The current study investigated the effect of binaural beats, a cognitive-enhancement technique, on attentional control in an attentional blink (AB) task. As predicted from a neurocognitive approach to cognitive control, high-frequency binaural beats eliminated the AB, but only in individuals with low spontaneous eye-blink rates (indicating low striatal dopamine levels). This suggests that the way in which cognitive-enhancement techniques, such as binaural beats, affect cognitive performance depends on inter-individual differences. PMID:26089802

  17. Rate-constrained source separation for speech enhancement in wireless-communicated binaural hearing aids

    NASA Astrophysics Data System (ADS)

    Ayllón, David; Gil-Pita, Roberto; Rosa-Zurera, Manuel

    2013-12-01

    A recent trend in hearing aids is the connection of the left and right devices to collaborate between them. Binaural systems can provide natural binaural hearing and support the improvement of speech intelligibility in noise, but they require data transmission between both devices, which increases the power consumption. This paper presents a novel sound source separation algorithm for binaural speech enhancement based on supervised machine learning and time-frequency masking. The system is designed considering the power restrictions in hearing aids, constraining both the computational cost of the algorithm and the transmission bit rate. The transmission schema is optimized using a tailored evolutionary algorithm that assigns a different number of bits to each frequency band. The proposed algorithm requires less than 10% of the available computational resources for signal processing and obtains good separation performance using bit rates lower than 64 kbps.

  18. Binaural advantages in users of bimodal and bilateral cochlear implant devices

    PubMed Central

    Kokkinakis, Kostas; Pak, Natalie

    2014-01-01

    This paper investigates to what extent users of bilateral and bimodal fittings should expect to benefit from all three different binaural advantages found to be present in normal-hearing listeners. Head-shadow and binaural squelch are advantages occurring under spatially separated speech and noise, while summation emerges when speech and noise coincide in space. For 14 bilateral or bimodal listeners, speech reception thresholds in the presence of four-talker babble were measured in sound-field under various speech and noise configurations. Statistical analysis revealed significant advantages of head-shadow and summation for both bilateral and bimodal listeners. Squelch was significant only for bimodal listeners. PMID:24437856

  19. Binaural Diplacusis and Its Relationship with Hearing-Threshold Asymmetry

    PubMed Central

    Colin, David; Micheyl, Christophe; Girod, Anneline; Truy, Eric; Gallégo, Stéphane

    2016-01-01

    Binaural pitch diplacusis refers to a perceptual anomaly whereby the same sound is perceived as having a different pitch depending on whether it is presented in the left or the right ear. Results in the literature suggest that this phenomenon is more prevalent, and larger, in individuals with asymmetric hearing loss than in individuals with symmetric hearing. However, because studies devoted to this effect have thus far involved small samples, the prevalence of the effect, and its relationship with interaural asymmetries in hearing thresholds, remain unclear. In this study, psychometric functions for interaural pitch comparisons were measured in 55 subjects, including 12 normal-hearing and 43 hearing-impaired participants. Statistically significant pitch differences between the left and right ears were observed in normal-hearing participants, but the effect was usually small (less than 1.5/16 octave, or about 7%). For the hearing-impaired participants, statistically significant interaural pitch differences were found in about three-quarters of the cases. Moreover, for about half of these participants, the difference exceeded 1.5/16 octaves and, in some participants, was as large as or larger than 1/4 octave. This was the case even for the lowest frequency tested, 500 Hz. The pitch differences were weakly, but significantly, correlated with the difference in hearing thresholds between the two ears, such that larger threshold asymmetries were statistically associated with larger pitch differences. For the vast majority of the hearing-impaired participants, the direction of the pitch differences was such that pitch was perceived as higher on the side with the higher (i.e., ‘worse’) hearing thresholds than on the opposite side. These findings are difficult to reconcile with purely temporal models of pitch perception, but may be accounted for by place-based or spectrotemporal models. PMID:27536884

  20. Binaural Diplacusis and Its Relationship with Hearing-Threshold Asymmetry.

    PubMed

    Colin, David; Micheyl, Christophe; Girod, Anneline; Truy, Eric; Gallégo, Stéphane

    2016-01-01

    Binaural pitch diplacusis refers to a perceptual anomaly whereby the same sound is perceived as having a different pitch depending on whether it is presented in the left or the right ear. Results in the literature suggest that this phenomenon is more prevalent, and larger, in individuals with asymmetric hearing loss than in individuals with symmetric hearing. However, because studies devoted to this effect have thus far involved small samples, the prevalence of the effect, and its relationship with interaural asymmetries in hearing thresholds, remain unclear. In this study, psychometric functions for interaural pitch comparisons were measured in 55 subjects, including 12 normal-hearing and 43 hearing-impaired participants. Statistically significant pitch differences between the left and right ears were observed in normal-hearing participants, but the effect was usually small (less than 1.5/16 octave, or about 7%). For the hearing-impaired participants, statistically significant interaural pitch differences were found in about three-quarters of the cases. Moreover, for about half of these participants, the difference exceeded 1.5/16 octaves and, in some participants, was as large as or larger than 1/4 octave. This was the case even for the lowest frequency tested, 500 Hz. The pitch differences were weakly, but significantly, correlated with the difference in hearing thresholds between the two ears, such that larger threshold asymmetries were statistically associated with larger pitch differences. For the vast majority of the hearing-impaired participants, the direction of the pitch differences was such that pitch was perceived as higher on the side with the higher (i.e., 'worse') hearing thresholds than on the opposite side. These findings are difficult to reconcile with purely temporal models of pitch perception, but may be accounted for by place-based or spectrotemporal models. PMID:27536884

  1. Frequency-Shift Detectors Bind Binaural as Well as Monaural Frequency Representations

    ERIC Educational Resources Information Center

    Carcagno, Samuele; Semal, Catherine; Demany, Laurent

    2011-01-01

    Previous psychophysical work provided evidence for the existence of automatic frequency-shift detectors (FSDs) that establish perceptual links between successive sounds. In this study, we investigated the characteristics of the FSDs with respect to the binaural system. Listeners were presented with sound sequences consisting of a chord of pure…

  2. The benefit of binaural hearing in a cocktail party: Effect of location and type of interferer

    NASA Astrophysics Data System (ADS)

    Hawley, Monica L.; Litovsky, Ruth Y.; Culling, John F.

    2004-02-01

    The ``cocktail party problem'' was studied using virtual stimuli whose spatial locations were generated using anechoic head-related impulse responses from the AUDIS database [Blauert et al., J. Acoust. Soc. Am. 103, 3082 (1998)]. Speech reception thresholds (SRTs) were measured for Harvard IEEE sentences presented from the front in the presence of one, two, or three interfering sources. Four types of interferer were used: (1) other sentences spoken by the same talker, (2) time-reversed sentences of the same talker, (3) speech-spectrum shaped noise, and (4) speech-spectrum shaped noise, modulated by the temporal envelope of the sentences. Each interferer was matched to the spectrum of the target talker. Interferers were placed in several spatial configurations, either coincident with or separated from the target. Binaural advantage was derived by subtracting SRTs from listening with the ``better monaural ear'' from those for binaural listening. For a single interferer, there was a binaural advantage of 2-4 dB for all interferer types. For two or three interferers, the advantage was 2-4 dB for noise and speech-modulated noise, and 6-7 dB for speech and time-reversed speech. These data suggest that the benefit of binaural hearing for speech intelligibility is especially pronounced when there are multiple voiced interferers at different locations from the target, regardless of spatial configuration; measurements with fewer or with other types of interferers can underestimate this benefit.

  3. High-Frequency Binaural Beats Increase Cognitive Flexibility: Evidence from Dual-Task Crosstalk

    PubMed Central

    Hommel, Bernhard; Sellaro, Roberta; Fischer, Rico; Borg, Saskia; Colzato, Lorenza S.

    2016-01-01

    Increasing evidence suggests that cognitive-control processes can be configured to optimize either persistence of information processing (by amplifying competition between decision-making alternatives and top-down biasing of this competition) or flexibility (by dampening competition and biasing). We investigated whether high-frequency binaural beats, an auditory illusion suspected to act as a cognitive enhancer, have an impact on cognitive-control configuration. We hypothesized that binaural beats in the gamma range bias the cognitive-control style toward flexibility, which in turn should increase the crosstalk between tasks in a dual-task paradigm. We replicated earlier findings that the reaction time in the first-performed task is sensitive to the compatibility between the responses in the first and the second task—an indication of crosstalk. As predicted, exposing participants to binaural beats in the gamma range increased this effect as compared to a control condition in which participants were exposed to a continuous tone of 340 Hz. These findings provide converging evidence that the cognitive-control style can be systematically biased by inducing particular internal states; that high-frequency binaural beats bias the control style toward more flexibility; and that different styles are implemented by changing the strength of local competition and top-down bias. PMID:27605922

  4. High-Frequency Binaural Beats Increase Cognitive Flexibility: Evidence from Dual-Task Crosstalk.

    PubMed

    Hommel, Bernhard; Sellaro, Roberta; Fischer, Rico; Borg, Saskia; Colzato, Lorenza S

    2016-01-01

    Increasing evidence suggests that cognitive-control processes can be configured to optimize either persistence of information processing (by amplifying competition between decision-making alternatives and top-down biasing of this competition) or flexibility (by dampening competition and biasing). We investigated whether high-frequency binaural beats, an auditory illusion suspected to act as a cognitive enhancer, have an impact on cognitive-control configuration. We hypothesized that binaural beats in the gamma range bias the cognitive-control style toward flexibility, which in turn should increase the crosstalk between tasks in a dual-task paradigm. We replicated earlier findings that the reaction time in the first-performed task is sensitive to the compatibility between the responses in the first and the second task-an indication of crosstalk. As predicted, exposing participants to binaural beats in the gamma range increased this effect as compared to a control condition in which participants were exposed to a continuous tone of 340 Hz. These findings provide converging evidence that the cognitive-control style can be systematically biased by inducing particular internal states; that high-frequency binaural beats bias the control style toward more flexibility; and that different styles are implemented by changing the strength of local competition and top-down bias. PMID:27605922

  5. The Physiological Basis and Clinical Use of the Binaural Interaction Component of the Auditory Brainstem Response.

    PubMed

    Laumen, Geneviève; Ferber, Alexander T; Klump, Georg M; Tollin, Daniel J

    2016-01-01

    The auditory brainstem response (ABR) is a sound-evoked noninvasively measured electrical potential representing the sum of neuronal activity in the auditory brainstem and midbrain. ABR peak amplitudes and latencies are widely used in human and animal auditory research and for clinical screening. The binaural interaction component (BIC) of the ABR stands for the difference between the sum of the monaural ABRs and the ABR obtained with binaural stimulation. The BIC comprises a series of distinct waves, the largest of which (DN1) has been used for evaluating binaural hearing in both normal hearing and hearing-impaired listeners. Based on data from animal and human studies, the authors discuss the possible anatomical and physiological bases of the BIC (DN1 in particular). The effects of electrode placement and stimulus characteristics on the binaurally evoked ABR are evaluated. The authors review how interaural time and intensity differences affect the BIC and, analyzing these dependencies, draw conclusion about the mechanism underlying the generation of the BIC. Finally, the utility of the BIC for clinical diagnoses are summarized. PMID:27232077

  6. Perception of Binaural Cues Develops in Children Who Are Deaf through Bilateral Cochlear Implantation

    PubMed Central

    Gordon, Karen A.; Deighton, Michael R.; Abbasalipour, Parvaneh; Papsin, Blake C.

    2014-01-01

    There are significant challenges to restoring binaural hearing to children who have been deaf from an early age. The uncoordinated and poor temporal information available from cochlear implants distorts perception of interaural timing differences normally important for sound localization and listening in noise. Moreover, binaural development can be compromised by bilateral and unilateral auditory deprivation. Here, we studied perception of both interaural level and timing differences in 79 children/adolescents using bilateral cochlear implants and 16 peers with normal hearing. They were asked on which side of their head they heard unilaterally or bilaterally presented click- or electrical pulse- trains. Interaural level cues were identified by most participants including adolescents with long periods of unilateral cochlear implant use and little bilateral implant experience. Interaural timing cues were not detected by new bilateral adolescent users, consistent with previous evidence. Evidence of binaural timing detection was, for the first time, found in children who had much longer implant experience but it was marked by poorer than normal sensitivity and abnormally strong dependence on current level differences between implants. In addition, children with prior unilateral implant use showed a higher proportion of responses to their first implanted sides than children implanted simultaneously. These data indicate that there are functional repercussions of developing binaural hearing through bilateral cochlear implants, particularly when provided sequentially; nonetheless, children have an opportunity to use these devices to hear better in noise and gain spatial hearing. PMID:25531107

  7. Sound localization in the presence of multiple reflections using a binaurally integrated cross-correlation/auto-correlation mechanism.

    PubMed

    Braasch, Jonas

    2016-07-01

    A precedence effect model is described that can use a binaural signal to robustly localize a sound source in the presence of multiple reflections for the frontal horizontal plane. The model also estimates a room impulse response from a running binaural signal and determines the spatial locations and delays of early reflections, without any prior or additional knowledge of the source. A dual-layer cross-correlation/auto-correlation algorithm is used to determine the interaural time difference of the direct sound source component and to estimate a binaural activity pattern. PMID:27475205

  8. Binaural Fusion and Listening Effort in Children Who Use Bilateral Cochlear Implants: A Psychoacoustic and Pupillometric Study

    PubMed Central

    Steel, Morrison M.; Papsin, Blake C.; Gordon, Karen A.

    2015-01-01

    Bilateral cochlear implants aim to provide hearing to both ears for children who are deaf and promote binaural/spatial hearing. Benefits are limited by mismatched devices and unilaterally-driven development which could compromise the normal integration of left and right ear input. We thus asked whether children hear a fused image (ie. 1 vs 2 sounds) from their bilateral implants and if this “binaural fusion” reduces listening effort. Binaural fusion was assessed by asking 25 deaf children with cochlear implants and 24 peers with normal hearing whether they heard one or two sounds when listening to bilaterally presented acoustic click-trains/electric pulses (250 Hz trains of 36 ms presented at 1 Hz). Reaction times and pupillary changes were recorded simultaneously to measure listening effort. Bilaterally implanted children heard one image of bilateral input less frequently than normal hearing peers, particularly when intensity levels on each side were balanced. Binaural fusion declined as brainstem asymmetries increased and age at implantation decreased. Children implanted later had access to acoustic input prior to implantation due to progressive deterioration of hearing. Increases in both pupil diameter and reaction time occurred as perception of binaural fusion decreased. Results indicate that, without binaural level cues, children have difficulty fusing input from their bilateral implants to perceive one sound which costs them increased listening effort. Brainstem asymmetries exacerbate this issue. By contrast, later implantation, reflecting longer access to bilateral acoustic hearing, may have supported development of auditory pathways underlying binaural fusion. Improved integration of bilateral cochlear implant signals for children is required to improve their binaural hearing. PMID:25668423

  9. Lateralization and Binaural Interaction of Middle-Latency and Late-Brainstem Components of the Auditory Evoked Response.

    PubMed

    Dykstra, Andrew R; Burchard, Daniel; Starzynski, Christian; Riedel, Helmut; Rupp, Andre; Gutschalk, Alexander

    2016-08-01

    We used magnetoencephalography to examine lateralization and binaural interaction of the middle-latency and late-brainstem components of the auditory evoked response (the MLR and SN10, respectively). Click stimuli were presented either monaurally, or binaurally with left- or right-leading interaural time differences (ITDs). While early MLR components, including the N19 and P30, were larger for monaural stimuli presented contralaterally (by approximately 30 and 36 % in the left and right hemispheres, respectively), later components, including the N40 and P50, were larger ipsilaterally. In contrast, MLRs elicited by binaural clicks with left- or right-leading ITDs did not differ. Depending on filter settings, weak binaural interaction could be observed as early as the P13 but was clearly much larger for later components, beginning at the P30, indicating some degree of binaural linearity up to early stages of cortical processing. The SN10, an obscure late-brainstem component, was observed consistently in individuals and showed linear binaural additivity. The results indicate that while the MLR is lateralized in response to monaural stimuli-and not ITDs-this lateralization reverses from primarily contralateral to primarily ipsilateral as early as 40 ms post stimulus and is never as large as that seen with fMRI. PMID:27197812

  10. Binaural simulation of virtual stage environments for evaluation by the solo violinist

    NASA Astrophysics Data System (ADS)

    Chu, William

    2004-10-01

    A unique computational and testing model for assessing solo violinists' response to various acoustical conditions on-stage was developed and shown to be an effective study tool. Realtime binaural auralizations of CATT-Acoustic models of several different virtual stage-acoustic designs were examined with a small group of professional violinists. Perceived differences as expressed by the subjects were discussed and explored in light of the specific measured acoustical descriptors available through the model. Unlike acoustical descriptors developed for audience receivers, ease of playing, support, and other soloist concerns do not necessarily show strong correlation between different subjects. It was found that this binaural simulation technique could provide a basis for developing a personal contextual vocabulary, to better understand the desired acoustical response of individual musicians.

  11. Techniques and applications for binaural sound manipulation in human-machine interfaces

    NASA Technical Reports Server (NTRS)

    Begault, Durand R.; Wenzel, Elizabeth M.

    1990-01-01

    The implementation of binaural sound to speech and auditory sound cues (auditory icons) is addressed from both an applications and technical standpoint. Techniques overviewed include processing by means of filtering with head-related transfer functions. Application to advanced cockpit human interface systems is discussed, although the techniques are extendable to any human-machine interface. Research issues pertaining to three-dimensional sound displays under investigation at the Aerospace Human Factors Division at NASA Ames Research Center are described.

  12. Development of an Efficient Binaural Simulation for the Analysis of Structural Acoustic Data

    NASA Technical Reports Server (NTRS)

    Lalime, Aimee L.; Johnson, Marty E.; Rizzi, Stephen A. (Technical Monitor)

    2002-01-01

    Binaural or "virtual acoustic" representation has been proposed as a method of analyzing acoustic and vibroacoustic data. Unfortunately, this binaural representation can require extensive computer power to apply the Head Related Transfer Functions (HRTFs) to a large number of sources, as with a vibrating structure. This work focuses on reducing the number of real-time computations required in this binaural analysis through the use of Singular Value Decomposition (SVD) and Equivalent Source Reduction (ESR). The SVD method reduces the complexity of the HRTF computations by breaking the HRTFs into dominant singular values (and vectors). The ESR method reduces the number of sources to be analyzed in real-time computation by replacing sources on the scale of a structural wavelength with sources on the scale of an acoustic wavelength. It is shown that the effectiveness of the SVD and ESR methods improves as the complexity of the source increases. In addition, preliminary auralization tests have shown that the results from both the SVD and ESR methods are indistinguishable from the results found with the exhaustive method.

  13. Development of an Efficient Binaural Simulation for the Analysis of Structural Acoustic Data

    NASA Technical Reports Server (NTRS)

    Johnson, Marty E.; Lalime, Aimee L.; Grosveld, Ferdinand W.; Rizzi, Stephen A.; Sullivan, Brenda M.

    2003-01-01

    Applying binaural simulation techniques to structural acoustic data can be very computationally intensive as the number of discrete noise sources can be very large. Typically, Head Related Transfer Functions (HRTFs) are used to individually filter the signals from each of the sources in the acoustic field. Therefore, creating a binaural simulation implies the use of potentially hundreds of real time filters. This paper details two methods of reducing the number of real-time computations required by: (i) using the singular value decomposition (SVD) to reduce the complexity of the HRTFs by breaking them into dominant singular values and vectors and (ii) by using equivalent source reduction (ESR) to reduce the number of sources to be analyzed in real-time by replacing sources on the scale of a structural wavelength with sources on the scale of an acoustic wavelength. The ESR and SVD reduction methods can be combined to provide an estimated computation time reduction of 99.4% for the structural acoustic data tested. In addition, preliminary tests have shown that there is a 97% correlation between the results of the combined reduction methods and the results found with the current binaural simulation techniques

  14. Monaural and binaural hearing directivity in the bottlenose dolphin: evoked-potential study.

    PubMed

    Popov, Vladimir V; Supin, Alexander Ya; Klishin, Vladimir O; Bulgakova, Tatyana N

    2006-01-01

    Hearing thresholds as a function of sound-source azimuth were measured in bottlenose dolphins using an auditory evoked potential (AEP) technique. AEP recording from a region next to the ear allowed recording monaural responses. Thus, a monaural directivity diagram (a threshold-vs-azimuth function) was obtained. For comparison, binaural AEP components were recorded from the vertex to get standard binaural directivity diagrams. Both monaural and binaural diagrams were obtained at frequencies ranging from 8 to 128 kHz in quarter-octave steps. At all frequencies, the monaural diagram demonstrated asymmetry manifesting itself as: (1) lower thresholds at the ipsilateral azimuth as compared to the symmetrical contralateral azimuth and (2) ipsilateral shift of the lowest-threshold point. The directivity index increased with frequency: at the ipsilateral side it rose from 4.7 to 17.8 dB from 11.2 to 128 kHz, and from 10.5 to 15.6 dB at the contralateral side. The lowest-threshold azimuth shifted from 0 degrees at 90-128 kHz to 22.5 degrees at 8-11.2 kHz. The frequency-dependent variation of the lowest-threshold azimuth indicates the presence of two sound-receiving apertures at each head side: a high-frequency aperture with the axis directed frontally, and a low-frequency aperture with the axis directed laterally. PMID:16454317

  15. Binaural beats increase interhemispheric alpha-band coherence between auditory cortices.

    PubMed

    Solcà, Marco; Mottaz, Anaïs; Guggisberg, Adrian G

    2016-02-01

    Binaural beats (BBs) are an auditory illusion occurring when two tones of slightly different frequency are presented separately to each ear. BBs have been suggested to alter physiological and cognitive processes through synchronization of the brain hemispheres. To test this, we recorded electroencephalograms (EEG) at rest and while participants listened to BBs or a monaural control condition during which both tones were presented to both ears. We calculated for each condition the interhemispheric coherence, which expressed the synchrony between neural oscillations of both hemispheres. Compared to monaural beats and resting state, BBs enhanced interhemispheric coherence between the auditory cortices. Beat frequencies in the alpha (10 Hz) and theta (4 Hz) frequency range both increased interhemispheric coherence selectively at alpha frequencies. In a second experiment, we evaluated whether this coherence increase has a behavioral aftereffect on binaural listening. No effects were observed in a dichotic digit task performed immediately after BBs presentation. Our results suggest that BBs enhance alpha-band oscillation synchrony between the auditory cortices during auditory stimulation. This effect seems to reflect binaural integration rather than entrainment. PMID:26541421

  16. Two crossed axonal projections contribute to binaural unmasking of frequency-following responses in rat inferior colliculus.

    PubMed

    Du, Yi; Ma, Tianfang; Wang, Qian; Wu, Xihong; Li, Liang

    2009-11-01

    Frequency-following responses (FFRs) are sustained potentials based on phase-locked neural activities elicited by low- to medium-frequency periodical sound waveforms. Human brainstem FFRs, which are able to encode some critical acoustic features of speech, can be unmasked by binaural processing. However, the underlying unmasking mechanisms have not previously been reported. In rats, most neurons in the inferior colliculus (IC) exhibit binaural responses which are affected by axonal projections from both the contralateral dorsal nucleus of the lateral lemniscus (DNLL) and the contralateral IC. The present study investigated whether the contralateral DNLL and the contralateral IC modulate binaural unmasking of FFRs recorded in the rat IC. The results show that IC FFRs to the rat pain call (chatter) were enhanced by local injection of the excitatory glutamate receptor antagonist kynurenic acid (KYNA) into the contralateral DNLL but were reduced by KYNA injection into the contralateral IC. Introducing a disparity between the interaural time difference (ITD) of the FFR-eliciting chatter and the ITD of the masking noise enhanced IC FFRs. Moreover, the ITD-disparity-induced FFR enhancement was weakened by injection of KYNA into either the contralateral DNLL or the contralateral IC when the ipsilateral chatter preceded the contralateral chatter. Thus, binaural hearing can improve IC FFRs against noise masking. More importantly, both inhibitory projections from the contralateral DNLL and excitatory projections from the contralateral IC modulate IC FFRs and play a role in forming binaural unmasking of IC FFRs. PMID:19840111

  17. Speech Perception in Noise in Normally Hearing Children: Does Binaural Frequency Modulated Fitting Provide More Benefit than Monaural Frequency Modulated Fitting?

    PubMed

    Mukari, Siti Zamratol-Mai Sarah; Umat, Cila; Razak, Ummu Athiyah Abdul

    2011-07-01

    The aim of the present study was to compare the benefit of monaural versus binaural ear-level frequency modulated (FM) fitting on speech perception in noise in children with normal hearing. Reception threshold for sentences (RTS) was measured in no-FM, monaural FM, and binaural FM conditions in 22 normally developing children with bilateral normal hearing, aged 8 to 9 years old. Data were gathered using the Pediatric Malay Hearing in Noise Test (P-MyHINT) with speech presented from front and multi-talker babble presented from 90°, 180°, 270° azimuths in a sound treated booth. The results revealed that the use of either monaural or binaural ear level FM receivers provided significantly better mean RTSs than the no-FM condition (P<0.001). However, binaural FM did not produce a significantly greater benefit in mean RTS than monaural fitting. The benefit of binaural over monaural FM varies across individuals; while binaural fitting provided better RTSs in about 50% of study subjects, there were those in whom binaural fitting resulted in either deterioration or no additional improvement compared to monaural FM fitting. The present study suggests that the use of monaural ear-level FM receivers in children with normal hearing might provide similar benefit as binaural use. Individual subjects' variations of binaural FM benefit over monaural FM suggests that the decision to employ monaural or binaural fitting should be individualized. It should be noted however, that the current study recruits typically developing normal hearing children. Future studies involving normal hearing children with high risk of having difficulty listening in noise is indicated to see if similar findings are obtained. PMID:26557323

  18. Auditory driving of the autonomic nervous system: Listening to theta-frequency binaural beats post-exercise increases parasympathetic activation and sympathetic withdrawal

    PubMed Central

    McConnell, Patrick A.; Froeliger, Brett; Garland, Eric L.; Ives, Jeffrey C.; Sforzo, Gary A.

    2014-01-01

    Binaural beats are an auditory illusion perceived when two or more pure tones of similar frequencies are presented dichotically through stereo headphones. Although this phenomenon is thought to facilitate state changes (e.g., relaxation), few empirical studies have reported on whether binaural beats produce changes in autonomic arousal. Therefore, the present study investigated the effects of binaural beating on autonomic dynamics [heart rate variability (HRV)] during post-exercise relaxation. Subjects (n = 21; 18–29 years old) participated in a double-blind, placebo-controlled study during which binaural beats and placebo were administered over two randomized and counterbalanced sessions (within-subjects repeated-measures design). At the onset of each visit, subjects exercised for 20-min; post-exercise, subjects listened to either binaural beats (‘wide-band’ theta-frequency binaural beats) or placebo (carrier tones) for 20-min while relaxing alone in a quiet, low-light environment. Dependent variables consisted of high-frequency (HF, reflecting parasympathetic activity), low-frequency (LF, reflecting sympathetic and parasympathetic activity), and LF/HF normalized powers, as well as self-reported relaxation. As compared to the placebo visit, the binaural-beat visit resulted in greater self-reported relaxation, increased parasympathetic activation and increased sympathetic withdrawal. By the end of the 20-min relaxation period there were no observable differences in HRV between binaural-beat and placebo visits, although binaural-beat associated HRV significantly predicted subsequent reported relaxation. Findings suggest that listening to binaural beats may exert an acute influence on both LF and HF components of HRV and may increase subjective feelings of relaxation. PMID:25452734

  19. 4D time-frequency representation for binaural speech signal processing

    NASA Astrophysics Data System (ADS)

    Mikhael, Raed; Szu, Harold H.

    2006-04-01

    Hearing is the ability to detect and process auditory information produced by the vibrating hair cilia residing in the corti of the ears to the auditory cortex of the brain via the auditory nerve. The primary and secondary corti of the brain interact with one another to distinguish and correlate the received information by distinguishing the varying spectrum of arriving frequencies. Binaural hearing is nature's way of employing the power inherent in working in pairs to process information, enhance sound perception, and reduce undesired noise. One ear might play a prominent role in sound recognition, while the other reinforces their perceived mutual information. Developing binaural hearing aid devices can be crucial in emulating the working powers of two ears and may be a step closer to significantly alleviating hearing loss of the inner ear. This can be accomplished by combining current speech research to already existing technologies such as RF communication between PDAs and Bluetooth. Ear Level Instrument (ELI) developed by Micro-tech Hearing Instruments and Starkey Laboratories is a good example of a digital bi-directional signal communicating between a PDA/mobile phone and Bluetooth. The agreement and disagreement of arriving auditory information to the Bluetooth device can be classified as sound and noise, respectively. Finding common features of arriving sound using a four coordinate system for sound analysis (four dimensional time-frequency representation), noise can be greatly reduced and hearing aids would become more efficient. Techniques developed by Szu within an Artificial Neural Network (ANN), Blind Source Separation (BSS), Adaptive Wavelets Transform (AWT), and Independent Component Analysis (ICA) hold many possibilities to the improvement of acoustic segmentation of phoneme, all of which will be discussed in this paper. Transmitted and perceived acoustic speech signal will improve, as the binaural hearing aid will emulate two ears in sound

  20. Sound-by-sound thalamic stimulation modulates midbrain auditory excitability and relative binaural sensitivity in frogs

    PubMed Central

    Ponnath, Abhilash; Farris, Hamilton E.

    2014-01-01

    Descending circuitry can modulate auditory processing, biasing sensitivity to particular stimulus parameters and locations. Using awake in vivo single unit recordings, this study tested whether electrical stimulation of the thalamus modulates auditory excitability and relative binaural sensitivity in neurons of the amphibian midbrain. In addition, by using electrical stimuli that were either longer than the acoustic stimuli (i.e., seconds) or presented on a sound-by-sound basis (ms), experiments addressed whether the form of modulation depended on the temporal structure of the electrical stimulus. Following long duration electrical stimulation (3–10 s of 20 Hz square pulses), excitability (spikes/acoustic stimulus) to free-field noise stimuli decreased by 32%, but returned over 600 s. In contrast, sound-by-sound electrical stimulation using a single 2 ms duration electrical pulse 25 ms before each noise stimulus caused faster and varied forms of modulation: modulation lasted <2 s and, in different cells, excitability either decreased, increased or shifted in latency. Within cells, the modulatory effect of sound-by-sound electrical stimulation varied between different acoustic stimuli, including for different male calls, suggesting modulation is specific to certain stimulus attributes. For binaural units, modulation depended on the ear of input, as sound-by-sound electrical stimulation preceding dichotic acoustic stimulation caused asymmetric modulatory effects: sensitivity shifted for sounds at only one ear, or by different relative amounts for both ears. This caused a change in the relative difference in binaural sensitivity. Thus, sound-by-sound electrical stimulation revealed fast and ear-specific (i.e., lateralized) auditory modulation that is potentially suited to shifts in auditory attention during sound segregation in the auditory scene. PMID:25120437

  1. A function for binaural integration in auditory grouping and segregation in the inferior colliculus.

    PubMed

    Nakamoto, Kyle T; Shackleton, Trevor M; Magezi, David A; Palmer, Alan R

    2015-03-15

    Responses of neurons to binaural, harmonic complex stimuli in urethane-anesthetized guinea pig inferior colliculus (IC) are reported. To assess the binaural integration of harmonicity cues for sound segregation and grouping, responses were measured to harmonic complexes with different fundamental frequencies presented to each ear. Simultaneously gated harmonic stimuli with fundamental frequencies of 125 Hz and 145 Hz were presented to the left and right ears, respectively, and recordings made from 96 neurons with characteristic frequencies >2 kHz in the central nucleus of the IC. Of these units, 70 responded continuously throughout the stimulus and were excited by the stimulus at the contralateral ear. The stimulus at the ipsilateral ear excited (EE: 14%; 10/70), inhibited (EI: 33%; 23/70), or had no significant effect (EO: 53%; 37/70), defined by the effect on firing rate. The neurons phase locked to the temporal envelope at each ear to varying degrees depending on signal level. Many of the cells (predominantly EO) were dominated by the response to the contralateral stimulus. Another group (predominantly EI) synchronized to the contralateral stimulus and were suppressed by the ipsilateral stimulus in a phasic manner. A third group synchronized to the stimuli at both ears (predominantly EE). Finally, a group only responded when the waveform peaks from each ear coincided. We conclude that these groups of neurons represent different "streams" of information but exhibit modifications of the response rather than encoding a feature of the stimulus, like pitch. PMID:25540219

  2. Prediction of the influence of reverberation on binaural speech intelligibility in noise and in quiet.

    PubMed

    Rennies, Jan; Brand, Thomas; Kollmeier, Birger

    2011-11-01

    Reverberation usually degrades speech intelligibility for spatially separated speech and noise sources since spatial unmasking is reduced and late reflections decrease the fidelity of the received speech signal. The latter effect could not satisfactorily be predicted by a recently presented binaural speech intelligibility model [Beutelmann et al. (2010). J. Acoust. Soc. Am. 127, 2479-2497]. This study therefore evaluated three extensions of the model to improve its predictions: (1) an extension of the speech intelligibility index based on modulation transfer functions, (2) a correction factor based on the room acoustical quantity "definition," and (3) a separation of the speech signal into useful and detrimental parts. The predictions were compared to results of two experiments in which speech reception thresholds were measured in a reverberant room in quiet and in the presence of a noise source for listeners with normal hearing. All extensions yielded better predictions than the original model when the influence of reverberation was strong, while predictions were similar for conditions with less reverberation. Although model (3) differed substantially in the assumed interaction of binaural processing and early reflections, its predictions were very similar to model (2) that achieved the best fit to the data. PMID:22087928

  3. Representation of binaural spatial cues in field L of the barn owl forebrain.

    PubMed

    Cohen, Y E; Knudsen, E I

    1998-02-01

    This study examined the representation of spatial information in the barn owl Field L, the first telencephalic processing stage of the classical auditory pathway. Field L units were recorded extracellularly, and their responses to dichotically presented interaural time differences (ITD) and interaural level differences (ILD) were tested. We observed a variety of tuning profiles in Field L. Some sites were not sensitive to ITD or ILD. Other sites, especially those in the high-frequency region, were highly selective for values of ITD and ILD. These sites had multipeaked (commonly called "phase ambiguous") ITD tuning profiles and were tuned for a single value of ILD. The tuning properties of these sites are similar to those seen in the lateral shell of the central nucleus of the inferior colliculus. Although the tuning properties of Field L sites were similar to those observed in the inferior colliculus, the functional organization of this spatial information was fundamentally different. Whereas in the inferior colliculus spatial information is organized into global topographics maps, in Field L spatial information is organized into local clusters, with sites having similar binaural tuning properties grouped together. The representation of binaural cues in Field L suggests that it is involved in auditory space processing but at a lower level of information processing than the auditory archistriatum, a forebrain area that is specialized for processing spatial information, and that the levels of information processing in the forebrain space processing pathway are remarkably similar to those in the well-known midbrain space processing pathway. PMID:9463449

  4. A function for binaural integration in auditory grouping and segregation in the inferior colliculus

    PubMed Central

    Shackleton, Trevor M.; Magezi, David A.; Palmer, Alan R.

    2014-01-01

    Responses of neurons to binaural, harmonic complex stimuli in urethane-anesthetized guinea pig inferior colliculus (IC) are reported. To assess the binaural integration of harmonicity cues for sound segregation and grouping, responses were measured to harmonic complexes with different fundamental frequencies presented to each ear. Simultaneously gated harmonic stimuli with fundamental frequencies of 125 Hz and 145 Hz were presented to the left and right ears, respectively, and recordings made from 96 neurons with characteristic frequencies >2 kHz in the central nucleus of the IC. Of these units, 70 responded continuously throughout the stimulus and were excited by the stimulus at the contralateral ear. The stimulus at the ipsilateral ear excited (EE: 14%; 10/70), inhibited (EI: 33%; 23/70), or had no significant effect (EO: 53%; 37/70), defined by the effect on firing rate. The neurons phase locked to the temporal envelope at each ear to varying degrees depending on signal level. Many of the cells (predominantly EO) were dominated by the response to the contralateral stimulus. Another group (predominantly EI) synchronized to the contralateral stimulus and were suppressed by the ipsilateral stimulus in a phasic manner. A third group synchronized to the stimuli at both ears (predominantly EE). Finally, a group only responded when the waveform peaks from each ear coincided. We conclude that these groups of neurons represent different “streams” of information but exhibit modifications of the response rather than encoding a feature of the stimulus, like pitch. PMID:25540219

  5. The neural substrate for binaural masking level differences in the auditory cortex.

    PubMed

    Gilbert, Heather J; Shackleton, Trevor M; Krumbholz, Katrin; Palmer, Alan R

    2015-01-01

    The binaural masking level difference (BMLD) is a phenomenon whereby a signal that is identical at each ear (S0), masked by a noise that is identical at each ear (N0), can be made 12-15 dB more detectable by inverting the waveform of either the tone or noise at one ear (Sπ, Nπ). Single-cell responses to BMLD stimuli were measured in the primary auditory cortex of urethane-anesthetized guinea pigs. Firing rate was measured as a function of signal level of a 500 Hz pure tone masked by low-passed white noise. Responses were similar to those reported in the inferior colliculus. At low signal levels, the response was dominated by the masker. At higher signal levels, firing rate either increased or decreased. Detection thresholds for each neuron were determined using signal detection theory. Few neurons yielded measurable detection thresholds for all stimulus conditions, with a wide range in thresholds. However, across the entire population, the lowest thresholds were consistent with human psychophysical BMLDs. As in the inferior colliculus, the shape of the firing-rate versus signal-level functions depended on the neurons' selectivity for interaural time difference. Our results suggest that, in cortex, BMLD signals are detected from increases or decreases in the firing rate, consistent with predictions of cross-correlation models of binaural processing and that the psychophysical detection threshold is based on the lowest neural thresholds across the population. PMID:25568115

  6. The Neural Substrate for Binaural Masking Level Differences in the Auditory Cortex

    PubMed Central

    Gilbert, Heather J.; Krumbholz, Katrin; Palmer, Alan R.

    2015-01-01

    The binaural masking level difference (BMLD) is a phenomenon whereby a signal that is identical at each ear (S0), masked by a noise that is identical at each ear (N0), can be made 12–15 dB more detectable by inverting the waveform of either the tone or noise at one ear (Sπ, Nπ). Single-cell responses to BMLD stimuli were measured in the primary auditory cortex of urethane-anesthetized guinea pigs. Firing rate was measured as a function of signal level of a 500 Hz pure tone masked by low-passed white noise. Responses were similar to those reported in the inferior colliculus. At low signal levels, the response was dominated by the masker. At higher signal levels, firing rate either increased or decreased. Detection thresholds for each neuron were determined using signal detection theory. Few neurons yielded measurable detection thresholds for all stimulus conditions, with a wide range in thresholds. However, across the entire population, the lowest thresholds were consistent with human psychophysical BMLDs. As in the inferior colliculus, the shape of the firing-rate versus signal-level functions depended on the neurons' selectivity for interaural time difference. Our results suggest that, in cortex, BMLD signals are detected from increases or decreases in the firing rate, consistent with predictions of cross-correlation models of binaural processing and that the psychophysical detection threshold is based on the lowest neural thresholds across the population. PMID:25568115

  7. Using a binaural biomimetic array to identify bottom objects ensonified by echolocating dolphins

    USGS Publications Warehouse

    Heiweg, D.A.; Moore, P.W.; Martin, S.W.; Dankiewicz, L.A.

    2006-01-01

    The development of a unique dolphin biomimetic sonar produced data that were used to study signal processing methods for object identification. Echoes from four metallic objects proud on the bottom, and a substrate-only condition, were generated by bottlenose dolphins trained to ensonify the targets in very shallow water. Using the two-element ('binaural') receive array, object echo spectra were collected and submitted for identification to four neural network architectures. Identification accuracy was evaluated over two receive array configurations, and five signal processing schemes. The four neural networks included backpropagation, learning vector quantization, genetic learning and probabilistic network architectures. The processing schemes included four methods that capitalized on the binaural data, plus a monaural benchmark process. All the schemes resulted in above-chance identification accuracy when applied to learning vector quantization and backpropagation. Beam-forming or concatenation of spectra from both receive elements outperformed the monaural benchmark, with higher sensitivity and lower bias. Ultimately, best object identification performance was achieved by the learning vector quantization network supplied with beam-formed data. The advantages of multi-element signal processing for object identification are clearly demonstrated in this development of a first-ever dolphin biomimetic sonar. ?? 2006 IOP Publishing Ltd.

  8. A Binaural CI Research Platform for Oticon Medical SP/XP Implants Enabling ITD/ILD and Variable Rate Processing.

    PubMed

    Backus, B; Adiloğlu, K; Herzke, T

    2015-01-01

    We present the first portable, binaural, real-time research platform compatible with Oticon Medical SP and XP generation cochlear implants. The platform consists of (a) a pair of behind-the-ear devices, each containing front and rear calibrated microphones, (b) a four-channel USB analog-to-digital converter, (c) real-time PC-based sound processing software called the Master Hearing Aid, and (d) USB-connected hardware and output coils capable of driving two implants simultaneously. The platform is capable of processing signals from the four microphones simultaneously and producing synchronized binaural cochlear implant outputs that drive two (bilaterally implanted) SP or XP implants. Both audio signal preprocessing algorithms (such as binaural beamforming) and novel binaural stimulation strategies (within the implant limitations) can be programmed by researchers. When the whole research platform is combined with Oticon Medical SP implants, interaural electrode timing can be controlled on individual electrodes to within ±1 µs and interaural electrode energy differences can be controlled to within ±2%. Hence, this new platform is particularly well suited to performing experiments related to interaural time differences in combination with interaural level differences in real-time. The platform also supports instantaneously variable stimulation rates and thereby enables investigations such as the effect of changing the stimulation rate on pitch perception. Because the processing can be changed on the fly, researchers can use this platform to study perceptual changes resulting from different processing strategies acutely. PMID:26721923

  9. The pattern of Fos expression in the rat auditory brainstem changes with the temporal structure of binaural electrical intracochlear stimulation.

    PubMed

    Jakob, Till F; Döring, Ulrike; Illing, Robert-Benjamin

    2015-04-01

    The immediate-early-gene c-fos with its protein product Fos has been used as a powerful tool to investigate neuronal activity and plasticity following sensory stimulation. Fos combines with Jun, another IEG product, to form the dimeric transcription factor activator protein 1 (AP-1) which has been implied in a variety of cellular functions like neuronal plasticity, apoptosis, and regeneration. The intracellular emergence of Fos indicates a functional state of nerve cells directed towards molecular and morphological changes. The central auditory system is construed to detect stimulus intensity, spectral composition, and binaural balance through neurons organized in a complex network of ascending, descending and commissural pathways. Here we compare monaural and binaural electrical intracochlear stimulation (EIS) in normal hearing and early postnatally deafened rats. Binaural stimulation was done either synchronously or asynchronously. The auditory brainstem of hearing and deaf rats responds differently, with a dramatically increasing Fos expression in the deaf group so as if the network had no pre-orientation for how to organize sensory activity. Binaural EIS does not result in a trivial sum of 2 independent monaural EIS, as asynchronous stimulation invokes stronger Fos activation compared to synchronous stimulation almost everywhere in the auditory brainstem. The differential response to synchronicity of the stimulation puts emphasis on the importance of the temporal structure of EIS with respect to its potential for changing brain structure and brain function in stimulus-specific ways. PMID:25708983

  10. A Binaural CI Research Platform for Oticon Medical SP/XP Implants Enabling ITD/ILD and Variable Rate Processing

    PubMed Central

    Adiloğlu, K.; Herzke, T.

    2015-01-01

    We present the first portable, binaural, real-time research platform compatible with Oticon Medical SP and XP generation cochlear implants. The platform consists of (a) a pair of behind-the-ear devices, each containing front and rear calibrated microphones, (b) a four-channel USB analog-to-digital converter, (c) real-time PC-based sound processing software called the Master Hearing Aid, and (d) USB-connected hardware and output coils capable of driving two implants simultaneously. The platform is capable of processing signals from the four microphones simultaneously and producing synchronized binaural cochlear implant outputs that drive two (bilaterally implanted) SP or XP implants. Both audio signal preprocessing algorithms (such as binaural beamforming) and novel binaural stimulation strategies (within the implant limitations) can be programmed by researchers. When the whole research platform is combined with Oticon Medical SP implants, interaural electrode timing can be controlled on individual electrodes to within ±1 µs and interaural electrode energy differences can be controlled to within ±2%. Hence, this new platform is particularly well suited to performing experiments related to interaural time differences in combination with interaural level differences in real-time. The platform also supports instantaneously variable stimulation rates and thereby enables investigations such as the effect of changing the stimulation rate on pitch perception. Because the processing can be changed on the fly, researchers can use this platform to study perceptual changes resulting from different processing strategies acutely. PMID:26721923

  11. Availability of binaural cues for bilateral implant recipients and bimodal listeners with and without preserved hearing in the implanted ear

    PubMed Central

    Dorman, Michael F.; Sheffield, Sterling W.; Teece, Kate; Olund, Amy P.; Gifford, René H.

    2014-01-01

    The purpose of the current study was to examine the availability of binaural cues for adult, bilateral cochlear implant (CI) patients, bimodal patients and hearing preservation patients using a multiple baseline, observational study design. Speech recognition was assessed using the Bamford-Kowal-Bench Speech-In-Noise (BKB-SIN) test as well as the AzBio sentences [Spahr et al., 2012] presented in a multi-talker babble at +5 dB signal-to-noise ratio (SNR). Test conditions included speech at 0° with noise presented at 0° (S0N0), 90° (S0N90), and 270° (S0N270). Estimates of summation, head shadow (HS), squelch, and spatial release from masking (SRM) were calculated. Though none of the subject groups consistently showed access to binaural cues, the hearing preservation patients exhibited a significant correlation between summation and squelch whereas the bilateral and bimodal participants did not. That is, the two effects associated with binaural hearing—summation and squelch—were positively correlated for only the listeners with bilateral acoustic hearing. This finding provides evidence for the supposition that implant recipients with bilateral acoustic hearing have access to binaural cues which should, in theory, provide greater benefit in noisy listening environments. It is likely, however, that the chosen test environment negatively affected the outcomes. Specifically, the spatially separated noise conditions directed noise toward the mic port of the behind-the-ear (BTE) hearing aid and implant processor. Thus it is possible that in more realistic listening environments for which the diffuse noise is not directed toward the processor/hearing aid mic, hearing preservation patients have binaural hearing cues for improved speech understanding. PMID:24356514

  12. The across frequency independence of equalization of interaural time delay in the equalization-cancellation model of binaural unmasking

    NASA Astrophysics Data System (ADS)

    Akeroyd, Michael A.

    2004-08-01

    The equalization stage in the equalization-cancellation model of binaural unmasking compensates for the interaural time delay (ITD) of a masking noise by introducing an opposite, internal delay [N. I. Durlach, in Foundations of Modern Auditory Theory, Vol. II., edited by J. V. Tobias (Academic, New York, 1972)]. Culling and Summerfield [J. Acoust. Soc. Am. 98, 785-797 (1995)] developed a multi-channel version of this model in which equalization was ``free'' to use the optimal delay in each channel. Two experiments were conducted to test if equalization was indeed free or if it was ``restricted'' to the same delay in all channels. One experiment measured binaural detection thresholds, using an adaptive procedure, for 1-, 5-, or 17-component tones against a broadband masking noise, in three binaural configurations (N0S180, N180S0, and N90S270). The thresholds for the 1-component stimuli were used to normalize the levels of each of the 5- and 17-component stimuli so that they were equally detectable. If equalization was restricted, then, for the 5- and 17-component stimuli, the N90S270 and N180S0 configurations would yield a greater threshold than the N0S180 configurations. No such difference was found. A subsequent experiment measured binaural detection thresholds, via psychometric functions, for a 2-component complex tone in the same three binaural configurations. Again, no differential effect of configuration was observed. An analytic model of the detection of a complex tone showed that the results were more consistent with free equalization than restricted equalization, although the size of the differences was found to depend on the shape of the psychometric function for detection.

  13. Spatial selectivity and binaural responses in the inferior colliculus of the great horned owl.

    PubMed

    Volman, S F; Konishi, M

    1989-09-01

    In this study we have investigated the processing of auditory cues for sound localization in the great horned owl (Bubo virginianus). Previous studies have shown that the barn owl, whose ears are asymmetrically oriented in the vertical plane, has a 2-dimensional, topographic representation of auditory space in the external division of the inferior colliculus (ICx). As in the barn owl, the great horned owl's ICx is anatomically distinct and projects to the optic tectum. Neurons in ICx respond over only a small range of azimuths (mean = 32 degrees), and azimuth is topographically mapped. In contrast to the barn owl, the great horned owl has bilaterally symmetrical ears and its receptive fields are not restricted in elevation. The binaural cues available for sound localization were measured both with cochlear microphonic recordings and with a microphone attached to a probe tube in the auditory canal. Interaural time disparity (ITD) varied monotonically with azimuth. Interaural intensity differences (IID) also changed with azimuth, but the largest IIDs were less than 15 dB, and the variation was not monotonic. Neither ITD nor IID varied systematically with changes in the vertical position of a sound source. We used dichotic stimulation to determine the sensitivity of ICx neurons to these binaural cues. Best ITD of ICx units was topographically mapped and strongly correlated with receptive-field azimuth. The width of ITD tuning curves, measured at 50% of the maximum response, averaged 72 microseconds. All ICx neurons responded only to binaural stimulation and had nonmonotonic IID tuning curves. Best IID was weakly, but significantly, correlated with best ITD (r = 0.39, p less than 0.05). The IID tuning curves, however, were broad (mean 50% width = 24 dB), and 67% of the units had best IIDs within 5 dB of 0 dB IID. ITD tuning was sensitive to variations in IID in the direction opposite to that expected for time-intensity trading, but the magnitude of this effect was only

  14. Electrophysiological and psychophysical asymmetries in sensitivity to interaural correlation gaps and implications for binaural integration time.

    PubMed

    Lüddemann, Helge; Kollmeier, Birger; Riedel, Helmut

    2016-02-01

    Brief deviations of interaural correlation (IAC) can provide valuable cues for detection, segregation and localization of acoustic signals. This study investigated the processing of such "binaural gaps" in continuously running noise (100-2000 Hz), in comparison to silent "monaural gaps", by measuring late auditory evoked potentials (LAEPs) and perceptual thresholds with novel, iteratively optimized stimuli. Mean perceptual binaural gap duration thresholds exhibited a major asymmetry: they were substantially shorter for uncorrelated gaps in correlated and anticorrelated reference noise (1.75 ms and 4.1 ms) than for correlated and anticorrelated gaps in uncorrelated reference noise (26.5 ms and 39.0 ms). The thresholds also showed a minor asymmetry: they were shorter in the positive than in the negative IAC range. The mean behavioral threshold for monaural gaps was 5.5 ms. For all five gap types, the amplitude of LAEP components N1 and P2 increased linearly with the logarithm of gap duration. While perceptual and electrophysiological thresholds matched for monaural gaps, LAEP thresholds were about twice as long as perceptual thresholds for uncorrelated gaps, but half as long for correlated and anticorrelated gaps. Nevertheless, LAEP thresholds showed the same asymmetries as perceptual thresholds. For gap durations below 30 ms, LAEPs were dominated by the processing of the leading edge of a gap. For longer gap durations, in contrast, both the leading and the lagging edge of a gap contributed to the evoked response. Formulae for the equivalent rectangular duration (ERD) of the binaural system's temporal window were derived for three common window shapes. The psychophysical ERD was 68 ms for diotic and about 40 ms for anti- and uncorrelated noise. After a nonlinear Z-transform of the stimulus IAC prior to temporal integration, ERDs were about 10 ms for reference correlations of ±1 and 80 ms for uncorrelated reference. Hence, a physiologically motivated

  15. Benefits to Speech Perception in Noise From the Binaural Integration of Electric and Acoustic Signals in Simulated Unilateral Deafness

    PubMed Central

    Ma, Ning; Morris, Saffron; Kitterick, Pádraig Thomas

    2016-01-01

    Objectives: This study used vocoder simulations with normal-hearing (NH) listeners to (1) measure their ability to integrate speech information from an NH ear and a simulated cochlear implant (CI), and (2) investigate whether binaural integration is disrupted by a mismatch in the delivery of spectral information between the ears arising from a misalignment in the mapping of frequency to place. Design: Eight NH volunteers participated in the study and listened to sentences embedded in background noise via headphones. Stimuli presented to the left ear were unprocessed. Stimuli presented to the right ear (referred to as the CI-simulation ear) were processed using an eight-channel noise vocoder with one of the three processing strategies. An Ideal strategy simulated a frequency-to-place map across all channels that matched the delivery of spectral information between the ears. A Realistic strategy created a misalignment in the mapping of frequency to place in the CI-simulation ear where the size of the mismatch between the ears varied across channels. Finally, a Shifted strategy imposed a similar degree of misalignment in all channels, resulting in consistent mismatch between the ears across frequency. The ability to report key words in sentences was assessed under monaural and binaural listening conditions and at signal to noise ratios (SNRs) established by estimating speech-reception thresholds in each ear alone. The SNRs ensured that the monaural performance of the left ear never exceeded that of the CI-simulation ear. The advantages of binaural integration were calculated by comparing binaural performance with monaural performance using the CI-simulation ear alone. Thus, these advantages reflected the additional use of the experimentally constrained left ear and were not attributable to better-ear listening. Results: Binaural performance was as accurate as, or more accurate than, monaural performance with the CI-simulation ear alone. When both ears supported a

  16. Binaural Simulation Experiments in the NASA Langley Structural Acoustics Loads and Transmission Facility

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.; Silcox, Richard (Technical Monitor)

    2001-01-01

    A location and positioning system was developed and implemented in the anechoic chamber of the Structural Acoustics Loads and Transmission (SALT) facility to accurately determine the coordinates of points in three-dimensional space. Transfer functions were measured between a shaker source at two different panel locations and the vibrational response distributed over the panel surface using a scanning laser vibrometer. The binaural simulation test matrix included test runs for several locations of the measuring microphones, various attitudes of the mannequin, two locations of the shaker excitation and three different shaker inputs including pulse, broadband random, and pseudo-random. Transfer functions, auto spectra, and coherence functions were acquired for the pseudo-random excitation. Time histories were acquired for the pulse and broadband random input to the shaker. The tests were repeated with a reflective surface installed. Binary data files were converted to universal format and archived on compact disk.

  17. Spectral overlap and interaural time difference sensitivity: Possible role of binaural interference

    PubMed Central

    Brown, Christopher A.; Yost, William A.

    2015-01-01

    A follow-up experiment to those conducted by Brown and Yost [(2011). J. Acoust. Soc. Am. 130, 358–364; (2013). Basic Aspects of Hearing: Physiology and Perception (Springer, London, UK)] examined interaural time difference (ITD) discrimination for a low-frequency target noise band flanked by monotic noise bands that were either lower-frequency than the target band, higher-frequency, or both. The flanking bands were either spectrally contiguous with the target band or spectrally separated. Significant interference in ITD processing occurred in the presence of the high-frequency flanking band. Results are discussed by way of a comparison of the conditions in the present study to those in studies of binaural interference. The possible role of attention is also discussed. PMID:25994736

  18. Lateral reflections are favorable in concert halls due to binaural loudness.

    PubMed

    Lokki, Tapio; Pätynen, Jukka

    2011-11-01

    A recent study on perceptual difference in simulated concert halls showed that a concert hall renders stronger sound with more bass when the temporal envelope of a signal is preserved in the reflections [Lokki et al., J. Acoust. Soc. Am. 129, EL223-EL228 (2011)]. In the same study the lateral reflections were shown to contribute to the perceived envelopment and openness. Moreover, the listening test results suggest that lateral reflections contribute to perception of sound source distance. Here, it is shown that lateral reflections are beneficial due to their increasing effect on binaural loudness-the phenomenon known well in psychoacoustics, but not in architectural acoustics. The reflections from the side are amplified more than median plane reflections, in particular at high frequencies, due to the shape of the human head. PMID:22088039

  19. Spectral overlap and interaural time difference sensitivity: possible role of binaural interference.

    PubMed

    Brown, Christopher A; Yost, William A

    2015-05-01

    A follow-up experiment to those conducted by Brown and Yost [(2011). J. Acoust. Soc. Am. 130, 358-364; (2013). Basic Aspects of Hearing: Physiology and Perception (Springer, London, UK)] examined interaural time difference (ITD) discrimination for a low-frequency target noise band flanked by monotic noise bands that were either lower-frequency than the target band, higher-frequency, or both. The flanking bands were either spectrally contiguous with the target band or spectrally separated. Significant interference in ITD processing occurred in the presence of the high-frequency flanking band. Results are discussed by way of a comparison of the conditions in the present study to those in studies of binaural interference. The possible role of attention is also discussed. PMID:25994736

  20. Comparison between bilateral cochlear implants and Neurelec Digisonic(®) SP Binaural cochlear implant: speech perception, sound localization and patient self-assessment.

    PubMed

    Bonnard, Damien; Lautissier, Sylvie; Bosset-Audoit, Amélie; Coriat, Géraldine; Beraha, Max; Maunoury, Antoine; Martel, Jacques; Darrouzet, Vincent; Bébéar, Jean-Pierre; Dauman, René

    2013-01-01

    An alternative to bilateral cochlear implantation is offered by the Neurelec Digisonic(®) SP Binaural cochlear implant, which allows stimulation of both cochleae within a single device. The purpose of this prospective study was to compare a group of Neurelec Digisonic(®) SP Binaural implant users (denoted BINAURAL group, n = 7) with a group of bilateral adult cochlear implant users (denoted BILATERAL group, n = 6) in terms of speech perception, sound localization, and self-assessment of health status and hearing disability. Speech perception was assessed using word recognition at 60 dB SPL in quiet and in a 'cocktail party' noise delivered through five loudspeakers in the hemi-sound field facing the patient (signal-to-noise ratio = +10 dB). The sound localization task was to determine the source of a sound stimulus among five speakers positioned between -90° and +90° from midline. Change in health status was assessed using the Glasgow Benefit Inventory and hearing disability was evaluated with the Abbreviated Profile of Hearing Aid Benefit. Speech perception was not statistically different between the two groups, even though there was a trend in favor of the BINAURAL group (mean percent word recognition in the BINAURAL and BILATERAL groups: 70 vs. 56.7% in quiet, 55.7 vs. 43.3% in noise). There was also no significant difference with regard to performance in sound localization and self-assessment of health status and hearing disability. On the basis of the BINAURAL group's performance in hearing tasks involving the detection of interaural differences, implantation with the Neurelec Digisonic(®) SP Binaural implant may be considered to restore effective binaural hearing. Based on these first comparative results, this device seems to provide benefits similar to those of traditional bilateral cochlear implantation, with a new approach to stimulate both auditory nerves. PMID:23548561

  1. Frequency response areas in the inferior colliculus: nonlinearity and binaural interaction

    PubMed Central

    Yu, Jane J.; Young, Eric D.

    2013-01-01

    The tuning, binaural properties, and encoding characteristics of neurons in the central nucleus of the inferior colliculus (CNIC) were investigated to shed light on nonlinearities in the responses of these neurons. Results were analyzed for three types of neurons (I, O, and V) in the CNIC of decerebrate cats. Rate responses to binaural stimuli were characterized using a 1st- plus 2nd-order spectral integration model. Parameters of the model were derived using broadband stimuli with random spectral shapes (RSS). This method revealed four characteristics of CNIC neurons: (1) Tuning curves derived from broadband stimuli have fixed (i. e., level tolerant) bandwidths across a 50–60 dB range of sound levels; (2) 1st-order contralateral weights (particularly for type I and O neurons) were usually larger in magnitude than corresponding ipsilateral weights; (3) contralateral weights were more important than ipsilateral weights when using the model to predict responses to untrained noise stimuli; and (4) 2nd-order weight functions demonstrate frequency selectivity different from that of 1st-order weight functions. Furthermore, while the inclusion of 2nd-order terms in the model usually improved response predictions related to untrained RSS stimuli, they had limited impact on predictions related to other forms of filtered broadband noise [e. g., virtual-space stimuli (VS)]. The accuracy of the predictions varied considerably by response type. Predictions were most accurate for I neurons, and less accurate for O and V neurons, except at the lowest stimulus levels. These differences in prediction performance support the idea that type I, O, and V neurons encode different aspects of the stimulus: while type I neurons are most capable of producing linear representations of spectral shape, type O and V neurons may encode spectral features or temporal stimulus properties in a manner not easily explained with the low-order model. Supported by NIH grant DC00115. PMID:23675323

  2. Intelligibility for Binaural Speech with Discarded Low-SNR Speech Components.

    PubMed

    Schoenmaker, Esther; van de Par, Steven

    2016-01-01

    Speech intelligibility in multitalker settings improves when the target speaker is spatially separated from the interfering speakers. A factor that may contribute to this improvement is the improved detectability of target-speech components due to binaural interaction in analogy to the Binaural Masking Level Difference (BMLD). This would allow listeners to hear target speech components within specific time-frequency intervals that have a negative SNR, similar to the improvement in the detectability of a tone in noise when these contain disparate interaural difference cues. To investigate whether these negative-SNR target-speech components indeed contribute to speech intelligibility, a stimulus manipulation was performed where all target components were removed when local SNRs were smaller than a certain criterion value. It can be expected that for sufficiently high criterion values target speech components will be removed that do contribute to speech intelligibility. For spatially separated speakers, assuming that a BMLD-like detection advantage contributes to intelligibility, degradation in intelligibility is expected already at criterion values below 0 dB SNR. However, for collocated speakers it is expected that higher criterion values can be applied without impairing speech intelligibility. Results show that degradation of intelligibility for separated speakers is only seen for criterion values of 0 dB and above, indicating a negligible contribution of a BMLD-like detection advantage in multitalker settings. These results show that the spatial benefit is related to a spatial separation of speech components at positive local SNRs rather than to a BMLD-like detection improvement for speech components at negative local SNRs. PMID:27080648

  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. PMID:12374342

  4. Neural ITD coding with bilateral cochlear implants: effect of binaurally coherent jitter

    PubMed Central

    Chung, Yoojin; Delgutte, Bertrand

    2012-01-01

    Poor sensitivity to the interaural time difference (ITD) constrains the ability of human bilateral cochlear implant users to listen in everyday noisy acoustic environments. ITD sensitivity to periodic pulse trains degrades sharply with increasing pulse rate but can be restored at high pulse rates by jittering the interpulse intervals in a binaurally coherent manner (Laback and Majdak. Binaural jitter improves interaural time-difference sensitivity of cochlear implantees at high pulse rates. Proc Natl Acad Sci USA 105: 814–817, 2008). We investigated the neural basis of the jitter effect by recording from single inferior colliculus (IC) neurons in bilaterally implanted, anesthetized cats. Neural responses to trains of biphasic pulses were measured as a function of pulse rate, jitter, and ITD. An effect of jitter on neural responses was most prominent for pulse rates above 300 pulses/s. High-rate periodic trains evoked only an onset response in most IC neurons, but introducing jitter increased ongoing firing rates in about half of these neurons. Neurons that had sustained responses to jittered high-rate pulse trains showed ITD tuning comparable with that produced by low-rate periodic pulse trains. Thus, jitter appears to improve neural ITD sensitivity by restoring sustained firing in many IC neurons. The effect of jitter on IC responses is qualitatively consistent with human psychophysics. Action potentials tended to occur reproducibly at sparse, preferred times across repeated presentations of high-rate jittered pulse trains. Spike triggered averaging of responses to jittered pulse trains revealed that firing was triggered by very short interpulse intervals. This suggests it may be possible to restore ITD sensitivity to periodic carriers by simply inserting short interpulse intervals at select times. PMID:22592306

  5. Perceptually aligning apical frequency regions leads to more binaural fusion of speech in a cochlear implant simulation.

    PubMed

    Staisloff, Hannah E; Lee, Daniel H; Aronoff, Justin M

    2016-07-01

    For bilateral cochlear implant users, the left and right arrays are typically not physically aligned, resulting in a degradation of binaural fusion, which can be detrimental to binaural abilities. Perceptually aligning the two arrays can be accomplished by disabling electrodes in one ear that do not have a perceptually corresponding electrode in the other side. However, disabling electrodes at the edges of the array will cause compression of the input frequency range into a smaller cochlear extent, which may result in reduced spectral resolution. An alternative approach to overcome this mismatch would be to only align one edge of the array. By aligning either only the apical or basal end of the arrays, fewer electrodes would be disabled, potentially causing less reduction in spectral resolution. The goal of this study was to determine the relative effect of aligning either the basal or apical end of the electrode with regards to binaural fusion. A vocoder was used to simulate cochlear implant listening conditions in normal hearing listeners. Speech signals were vocoded such that the two ears were either predominantly aligned at only the basal or apical end of the simulated arrays. The experiment was then repeated with a spectrally inverted vocoder to determine whether the detrimental effects on fusion were related to the spectral-temporal characteristics of the stimuli or the location in the cochlea where the misalignment occurred. In Experiment 1, aligning the basal portion of the simulated arrays led to significantly less binaural fusion than aligning the apical portions of the simulated array. However, when the input was spectrally inverted, aligning the apical portion of the simulated array led to significantly less binaural fusion than aligning the basal portions of the simulated arrays. These results suggest that, for speech, with its predominantly low frequency spectral-temporal modulations, it is more important to perceptually align the apical portion of

  6. Speech intelligibility prediction in reverberation: Towards an integrated model of speech transmission, spatial unmasking, and binaural de-reverberation.

    PubMed

    Leclère, Thibaud; Lavandier, Mathieu; Culling, John F

    2015-06-01

    Room acoustic indicators of intelligibility have focused on the effects of temporal smearing of speech by reverberation and masking by diffuse ambient noise. In the presence of a discrete noise source, these indicators neglect the binaural listener's ability to separate target speech from noise. Lavandier and Culling [(2010). J. Acoust. Soc. Am. 127, 387-399] proposed a model that incorporates this ability but neglects the temporal smearing of speech, so that predictions hold for near-field targets. An extended model based on useful-to-detrimental (U/D) ratios is presented here that accounts for temporal smearing, spatial unmasking, and binaural de-reverberation in reverberant environments. The influence of the model parameters was tested by comparing the model predictions with speech reception thresholds measured in three experiments from the literature. Accurate predictions were obtained by adjusting the parameters to each room. Room-independent parameters did not lead to similar performances, suggesting that a single U/D model cannot be generalized to any room. Despite this limitation, the model framework allows to propose a unified interpretation of spatial unmasking, temporal smearing, and binaural de-reverberation. PMID:26093423

  7. Binaural speech unmasking and localization in noise with bilateral cochlear implants using envelope and fine-timing based strategies.

    PubMed

    van Hoesel, Richard; Böhm, Melanie; Pesch, Jörg; Vandali, Andrew; Battmer, Rolf D; Lenarz, Thomas

    2008-04-01

    Four adult bilateral cochlear implant users, with good open-set sentence recognition, were tested with three different sound coding strategies for binaural speech unmasking and their ability to localize 100 and 500 Hz click trains in noise. Two of the strategies tested were envelope-based strategies that are clinically widely used. The third was a research strategy that additionally preserved fine-timing cues at low frequencies. Speech reception thresholds were determined in diotic noise for diotic and interaurally time-delayed speech using direct audio input to a bilateral research processor. Localization in noise was assessed in the free field. Overall results, for both speech and localization tests, were similar with all three strategies. None provided a binaural speech unmasking advantage due to the application of 700 micros interaural time delay to the speech signal, and localization results showed similar response patterns across strategies that were well accounted for by the use of broadband interaural level cues. The data from both experiments combined indicate that, in contrast to normal hearing, timing cues available from natural head-width delays do not offer binaural advantages with present methods of electrical stimulation, even when fine-timing cues are explicitly coded. PMID:18397030

  8. Responses of neurons in the auditory pathway of the barn owl to partially correlated binaural signals.

    PubMed

    Albeck, Y; Konishi, M

    1995-10-01

    1. Extracellular single-unit recording in anesthetized barn owls was used to study neuronal response to dichotic stimuli of variable binaural correlation (BC). Recordings were made in the output fibers of nucleus laminaris (NL), the anterior division of the ventral lateral lemniscal nucleus (VLVa), the core of the central nucleus of the inferior colliculus (ICcC), the lateral shell of the central nucleus of the inferior colliculus (ICcLS), and the external nucleus of the inferior colliculus (ICx). 2. The response of all neurons sensitive to interaural time difference (ITD) varied with BC. The relationship between BC and impulse number fits a linear, a parabolic, or a ramp model. A linear or parabolic model fits most neurons in low-level nuclei. Higher order neurons in ICx did not respond to noise bursts with strong negative binaural correlation, creating a ramp-like response to BC. 3. A neuron's ability to detect ITD varied as a function of BC. Conversely, a neuron's response to BC changed with ITD. Neurons in NL, VLVa, and ICcC show almost periodic ITD response curves. In these neurons peaks and troughs of ITD response curves diminished as BC decreased, creating a flat ITD response when BC = 0. When BC was set to -1, the most favorable ITD became the least favorable one and vice versa. The ITD response curve of ICx neurons usually has a single dominant peak. The response of those neurons to a negatively correlated noise pair (BC = -1) showed two ITD peaks, flanking the position of the primary peak. 4. The parabolic BC response of NL neurons fits the prediction of the cross-correlation model, assuming half-wave rectification of the sound by the cochlea. Linear response is not predicted by the model. However, the parabolic and the linear neurons probably do not belong to two distinct groups as the difference between them is not statistically significant. Thus, the cross-correlation model provides a good description of the binaural response not only in NL but also in

  9. Analysis of EEG activity in response to binaural beats with different frequencies.

    PubMed

    Gao, Xiang; Cao, Hongbao; Ming, Dong; Qi, Hongzhi; Wang, Xuemin; Wang, Xiaolu; Chen, Runge; Zhou, Peng

    2014-12-01

    When two coherent sounds with nearly similar frequencies are presented to each ear respectively with stereo headphones, the brain integrates the two signals and produces a sensation of a third sound called binaural beat (BB). Although earlier studies showed that BB could influence behavior and cognition, common agreement on the mechanism of BB has not been reached yet. In this work, we employed Relative Power (RP), Phase Locking Value (PLV) and Cross-Mutual Information (CMI) to track EEG changes during BB stimulations. EEG signals were acquired from 13 healthy subjects. Five-minute BBs with four different frequencies were tested: delta band (1 Hz), theta band (5 Hz), alpha band (10 Hz) and beta band (20 Hz). We observed RP increase in theta and alpha bands and decrease in beta band during delta and alpha BB stimulations. RP decreased in beta band during theta BB, while RP decreased in theta band during beta BB. However, no clear brainwave entrainment effect was identified. Connectivity changes were detected following the variation of RP during BB stimulations. Our observation supports the hypothesis that BBs could affect functional brain connectivity, suggesting that the mechanism of BB-brain interaction is worth further study. PMID:25448376

  10. A Binaural Steering Beamformer System for Enhancing a Moving Speech Source.

    PubMed

    Adiloğlu, Kamil; Kayser, Hendrik; Baumgärtel, Regina M; Rennebeck, Sanja; Dietz, Mathias; Hohmann, Volker

    2015-01-01

    In many daily life communication situations, several sound sources are simultaneously active. While normal-hearing listeners can easily distinguish the target sound source from interfering sound sources-as long as target and interferers are spatially or spectrally separated-and concentrate on the target, hearing-impaired listeners and cochlear implant users have difficulties in making such a distinction. In this article, we propose a binaural approach composed of a spatial filter controlled by a direction-of-arrival estimator to track and enhance a moving target sound. This approach was implemented on a real-time signal processing platform enabling experiments with test subjects in situ. To evaluate the proposed method, a data set of sound signals with a single moving sound source in an anechoic diffuse noise environment was generated using virtual acoustics. The proposed steering method was compared with a fixed (nonsteering) method that enhances sound from the frontal direction in an objective evaluation and subjective experiments using this database. In both cases, the obtained results indicated a significant improvement in speech intelligibility and quality compared with the unprocessed signal. Furthermore, the proposed method outperformed the nonsteering method. PMID:26721924

  11. A Binaural Steering Beamformer System for Enhancing a Moving Speech Source

    PubMed Central

    Kayser, Hendrik; Baumgärtel, Regina M.; Rennebeck, Sanja; Dietz, Mathias; Hohmann, Volker

    2015-01-01

    In many daily life communication situations, several sound sources are simultaneously active. While normal-hearing listeners can easily distinguish the target sound source from interfering sound sources—as long as target and interferers are spatially or spectrally separated—and concentrate on the target, hearing-impaired listeners and cochlear implant users have difficulties in making such a distinction. In this article, we propose a binaural approach composed of a spatial filter controlled by a direction-of-arrival estimator to track and enhance a moving target sound. This approach was implemented on a real-time signal processing platform enabling experiments with test subjects in situ. To evaluate the proposed method, a data set of sound signals with a single moving sound source in an anechoic diffuse noise environment was generated using virtual acoustics. The proposed steering method was compared with a fixed (nonsteering) method that enhances sound from the frontal direction in an objective evaluation and subjective experiments using this database. In both cases, the obtained results indicated a significant improvement in speech intelligibility and quality compared with the unprocessed signal. Furthermore, the proposed method outperformed the nonsteering method. PMID:26721924

  12. Deriving content-specific measures of room acoustic perception using a binaural, nonlinear auditory model.

    PubMed

    van Dorp Schuitman, Jasper; de Vries, Diemer; Lindau, Alexander

    2013-03-01

    Acousticians generally assess the acoustic qualities of a concert hall or any other room using impulse response-based measures such as the reverberation time, clarity index, and others. These parameters are used to predict perceptual attributes related to the acoustic qualities of the room. Various studies show that these physical measures are not able to predict the related perceptual attributes sufficiently well under all circumstances. In particular, it has been shown that physical measures are dependent on the state of occupation, are prone to exaggerated spatial fluctuation, and suffer from lacking discrimination regarding the kind of acoustic stimulus being presented. Accordingly, this paper proposes a method for the derivation of signal-based measures aiming at predicting aspects of room acoustic perception from content specific signal representations produced by a binaural, nonlinear model of the human auditory system. Listening tests were performed to test the proposed auditory parameters for both speech and music. The results look promising; the parameters correlate with their corresponding perceptual attributes in most cases. PMID:23464027

  13. Postnatal development of sound pressure transformations by the head and pinnae of the cat: Binaural characteristics

    PubMed Central

    Tollin, Daniel J.; Koka, Kanthaiah

    2009-01-01

    There are three acoustical cues to sound location: Interaural time differences (ITDs), interaural level differences (ILDs), and monaural spectral shape cues. During development, the increasing interaural distance and pinnae size associated with a growing head and pinnae result in localization cues that change continuously until maturation is complete. Here the authors report measurements of both the physical dimensions of the head and pinnae, as well as acoustical measurements of the binaural localization cues of cats aged 1.3 weeks to adulthood. For a given source location, ILD magnitude tended to increase with both frequency and age. Moreover, the range of significant ILD production (∼10 dB) shifted with age from higher to lower frequencies. ITD magnitude increased with age. Partial correlation analyses revealed that increasing pinnae size accounted for ∼31% of the variance in the development of ILDs while increasing head size accounted for virtually none. On the other hand, increases in both the head and pinnae sizes contributed to the development of the ITD cues accounting for ∼71% and ∼25% of the variance, respectively. ILD and ITD cues in cats reach maturity by ∼16 and ∼22 weeks, respectively, which match the time period over which the pinnae and head dimensions reach maturity. PMID:20000926

  14. Evaluation of Speech Intelligibility and Sound Localization Abilities with Hearing Aids Using Binaural Wireless Technology

    PubMed Central

    Ibrahim, Iman; Parsa, Vijay; Macpherson, Ewan; Cheesman, Margaret

    2012-01-01

    Wireless synchronization of the digital signal processing (DSP) features between two hearing aids in a bilateral hearing aid fitting is a fairly new technology. This technology is expected to preserve the differences in time and intensity between the two ears by co-ordinating the bilateral DSP features such as multichannel compression, noise reduction, and adaptive directionality. The purpose of this study was to evaluate the benefits of wireless communication as implemented in two commercially available hearing aids. More specifically, this study measured speech intelligibility and sound localization abilities of normal hearing and hearing impaired listeners using bilateral hearing aids with wireless synchronization of multichannel Wide Dynamic Range Compression (WDRC). Twenty subjects participated; 8 had normal hearing and 12 had bilaterally symmetrical sensorineural hearing loss. Each individual completed the Hearing in Noise Test (HINT) and a sound localization test with two types of stimuli. No specific benefit from wireless WDRC synchronization was observed for the HINT; however, hearing impaired listeners had better localization with the wireless synchronization. Binaural wireless technology in hearing aids may improve localization abilities although the possible effect appears to be small at the initial fitting. With adaptation, the hearing aids with synchronized signal processing may lead to an improvement in localization and speech intelligibility. Further research is required to demonstrate the effect of adaptation to the hearing aids with synchronized signal processing on different aspects of auditory performance. PMID:26557339

  15. Aging effects on the binaural interaction component of the auditory brainstem response in the Mongolian gerbil: Effects of interaural time and level differences.

    PubMed

    Laumen, Geneviève; Tollin, Daniel J; Beutelmann, Rainer; Klump, Georg M

    2016-07-01

    The effect of interaural time difference (ITD) and interaural level difference (ILD) on wave 4 of the binaural and summed monaural auditory brainstem responses (ABRs) as well as on the DN1 component of the binaural interaction component (BIC) of the ABR in young and old Mongolian gerbils (Meriones unguiculatus) was investigated. Measurements were made at a fixed sound pressure level (SPL) and a fixed level above visually detected ABR threshold to compensate for individual hearing threshold differences. In both stimulation modes (fixed SPL and fixed level above visually detected ABR threshold) an effect of ITD on the latency and the amplitude of wave 4 as well as of the BIC was observed. With increasing absolute ITD values BIC latencies were increased and amplitudes were decreased. ILD had a much smaller effect on these measures. Old animals showed a reduced amplitude of the DN1 component. This difference was due to a smaller wave 4 in the summed monaural ABRs of old animals compared to young animals whereas wave 4 in the binaural-evoked ABR showed no age-related difference. In old animals the small amplitude of the DN1 component was correlated with small binaural-evoked wave 1 and wave 3 amplitudes. This suggests that the reduced peripheral input affects central binaural processing which is reflected in the BIC. PMID:27173973

  16. Binaural interaction in human auditory brainstem response compared for tone-pips and rectangular clicks under conditions of auditory and visual attention.

    PubMed

    Ikeda, Kazunari

    2015-07-01

    Binaural interaction in the auditory brainstem response (ABR) represents the discrepancy between the binaural waveform and the sum of monaural ones. A typical ABR binaural interaction in humans is a reduction of the binaural amplitude compared to the monaural sum at the wave-V latency, i.e., the DN1 component. It has been considered that the DN1 is mainly elicited by high frequency components of stimuli whereas some studies have shown the contribution of low-to-middle frequency components to the DN1. To examine this issue, the present study compared the ABR binaural interaction elicited by tone pips (1 kHz, 10-ms duration) with the one by clicks (a rectangular wave, 0.1-ms duration) presented at 80 dB peak equivalent SPL and a fixed stimulus onset interval (180 ms). The DN1 due to tone pips was vulnerable compared to the click-evoked DN1. The pip-evoked DN1 was significantly detected under auditory attention whereas it failed to reach significance under visual attention. The click-evoked DN1 was robustly present for the two attention conditions. The current results might confirm the high frequency sound contribution to the DN1 elicitation. PMID:25776741

  17. Capturing Movement

    ERIC Educational Resources Information Center

    Lord, Lynda

    2007-01-01

    The idea for the art lesson presented in this article grew out of watching the lively actions of fourth grade students. Since drawing is the author's first love, she is always looking for new ways to teach it. This time, instead of setting up a still life, she decided to teach students how to capture their actions on paper. (Contains 5 online…

  18. Laser capture.

    PubMed

    Potter, S Steven; Brunskill, Eric W

    2012-01-01

    This chapter describes detailed methods used for laser capture microdissection (LCM) of discrete subpopulations of cells. Topics covered include preparing tissue blocks, cryostat sectioning, processing slides, performing the LCM, and purification of RNA from LCM samples. Notes describe the fine points of each operation, which can often mean the difference between success and failure. PMID:22639264

  19. Structural Changes and Lack of HCN1 Channels in the Binaural Auditory Brainstem of the Naked Mole-Rat (Heterocephalus glaber)

    PubMed Central

    Gessele, Nikodemus; Garcia-Pino, Elisabet; Omerbašić, Damir; Park, Thomas J.; Koch, Ursula

    2016-01-01

    Naked mole-rats (Heterocephalus glaber) live in large eu-social, underground colonies in narrow burrows and are exposed to a large repertoire of communication signals but negligible binaural sound localization cues, such as interaural time and intensity differences. We therefore asked whether monaural and binaural auditory brainstem nuclei in the naked mole-rat are differentially adjusted to this acoustic environment. Using antibody stainings against excitatory and inhibitory presynaptic structures, namely the vesicular glutamate transporter VGluT1 and the glycine transporter GlyT2 we identified all major auditory brainstem nuclei except the superior paraolivary nucleus in these animals. Naked mole-rats possess a well structured medial superior olive, with a similar synaptic arrangement to interaural-time-difference encoding animals. The neighboring lateral superior olive, which analyzes interaural intensity differences, is large and elongated, whereas the medial nucleus of the trapezoid body, which provides the contralateral inhibitory input to these binaural nuclei, is reduced in size. In contrast, the cochlear nucleus, the nuclei of the lateral lemniscus and the inferior colliculus are not considerably different when compared to other rodent species. Most interestingly, binaural auditory brainstem nuclei lack the membrane-bound hyperpolarization-activated channel HCN1, a voltage-gated ion channel that greatly contributes to the fast integration times in binaural nuclei of the superior olivary complex in other species. This suggests substantially lengthened membrane time constants and thus prolonged temporal integration of inputs in binaural auditory brainstem neurons and might be linked to the severely degenerated sound localization abilities in these animals. PMID:26760498

  20. Comparing Binaural Pre-processing Strategies III: Speech Intelligibility of Normal-Hearing and Hearing-Impaired Listeners.

    PubMed

    Völker, Christoph; Warzybok, Anna; Ernst, Stephan M A

    2015-01-01

    A comprehensive evaluation of eight signal pre-processing strategies, including directional microphones, coherence filters, single-channel noise reduction, binaural beamformers, and their combinations, was undertaken with normal-hearing (NH) and hearing-impaired (HI) listeners. Speech reception thresholds (SRTs) were measured in three noise scenarios (multitalker babble, cafeteria noise, and single competing talker). Predictions of three common instrumental measures were compared with the general perceptual benefit caused by the algorithms. The individual SRTs measured without pre-processing and individual benefits were objectively estimated using the binaural speech intelligibility model. Ten listeners with NH and 12 HI listeners participated. The participants varied in age and pure-tone threshold levels. Although HI listeners required a better signal-to-noise ratio to obtain 50% intelligibility than listeners with NH, no differences in SRT benefit from the different algorithms were found between the two groups. With the exception of single-channel noise reduction, all algorithms showed an improvement in SRT of between 2.1 dB (in cafeteria noise) and 4.8 dB (in single competing talker condition). Model predictions with binaural speech intelligibility model explained 83% of the measured variance of the individual SRTs in the no pre-processing condition. Regarding the benefit from the algorithms, the instrumental measures were not able to predict the perceptual data in all tested noise conditions. The comparable benefit observed for both groups suggests a possible application of noise reduction schemes for listeners with different hearing status. Although the model can predict the individual SRTs without pre-processing, further development is necessary to predict the benefits obtained from the algorithms at an individual level. PMID:26721922

  1. The binaural masking level difference: cortical correlates persist despite severe brain stem atrophy in progressive supranuclear palsy

    PubMed Central

    Rowe, James B.; Ghosh, Boyd C. P.; Carlyon, Robert P.; Plack, Christopher J.; Gockel, Hedwig E.

    2014-01-01

    Under binaural listening conditions, the detection of target signals within background masking noise is substantially improved when the interaural phase of the target differs from that of the masker. Neural correlates of this binaural masking level difference (BMLD) have been observed in the inferior colliculus and temporal cortex, but it is not known whether degeneration of the inferior colliculus would result in a reduction of the BMLD in humans. We used magnetoencephalography to examine the BMLD in 13 healthy adults and 13 patients with progressive supranuclear palsy (PSP). PSP is associated with severe atrophy of the upper brain stem, including the inferior colliculus, confirmed by voxel-based morphometry of structural MRI. Stimuli comprised in-phase sinusoidal tones presented to both ears at three levels (high, medium, and low) masked by in-phase noise, which rendered the low-level tone inaudible. Critically, the BMLD was measured using a low-level tone presented in opposite phase across ears, making it audible against the noise. The cortical waveforms from bilateral auditory sources revealed significantly larger N1m peaks for the out-of-phase low-level tone compared with the in-phase low-level tone, for both groups, indicating preservation of early cortical correlates of the BMLD in PSP. In PSP a significant delay was observed in the onset of the N1m deflection and the amplitude of the P2m was reduced, but these differences were not restricted to the BMLD condition. The results demonstrate that although PSP causes subtle auditory deficits, binaural processing can survive the presence of significant damage to the upper brain stem. PMID:25231610

  2. Acoustic space learning for sound-source separation and localization on binaural manifolds.

    PubMed

    Deleforge, Antoine; Forbes, Florence; Horaud, Radu

    2015-02-01

    In this paper, we address the problems of modeling the acoustic space generated by a full-spectrum sound source and using the learned model for the localization and separation of multiple sources that simultaneously emit sparse-spectrum sounds. We lay theoretical and methodological grounds in order to introduce the binaural manifold paradigm. We perform an in-depth study of the latent low-dimensional structure of the high-dimensional interaural spectral data, based on a corpus recorded with a human-like audiomotor robot head. A nonlinear dimensionality reduction technique is used to show that these data lie on a two-dimensional (2D) smooth manifold parameterized by the motor states of the listener, or equivalently, the sound-source directions. We propose a probabilistic piecewise affine mapping model (PPAM) specifically designed to deal with high-dimensional data exhibiting an intrinsic piecewise linear structure. We derive a closed-form expectation-maximization (EM) procedure for estimating the model parameters, followed by Bayes inversion for obtaining the full posterior density function of a sound-source direction. We extend this solution to deal with missing data and redundancy in real-world spectrograms, and hence for 2D localization of natural sound sources such as speech. We further generalize the model to the challenging case of multiple sound sources and we propose a variational EM framework. The associated algorithm, referred to as variational EM for source separation and localization (VESSL) yields a Bayesian estimation of the 2D locations and time-frequency masks of all the sources. Comparisons of the proposed approach with several existing methods reveal that the combination of acoustic-space learning with Bayesian inference enables our method to outperform state-of-the-art methods. PMID:25164245

  3. The opponent channel population code of sound location is an efficient representation of natural binaural sounds.

    PubMed

    Młynarski, Wiktor

    2015-05-01

    In mammalian auditory cortex, sound source position is represented by a population of broadly tuned neurons whose firing is modulated by sounds located at all positions surrounding the animal. Peaks of their tuning curves are concentrated at lateral position, while their slopes are steepest at the interaural midline, allowing for the maximum localization accuracy in that area. These experimental observations contradict initial assumptions that the auditory space is represented as a topographic cortical map. It has been suggested that a "panoramic" code has evolved to match specific demands of the sound localization task. This work provides evidence suggesting that properties of spatial auditory neurons identified experimentally follow from a general design principle- learning a sparse, efficient representation of natural stimuli. Natural binaural sounds were recorded and served as input to a hierarchical sparse-coding model. In the first layer, left and right ear sounds were separately encoded by a population of complex-valued basis functions which separated phase and amplitude. Both parameters are known to carry information relevant for spatial hearing. Monaural input converged in the second layer, which learned a joint representation of amplitude and interaural phase difference. Spatial selectivity of each second-layer unit was measured by exposing the model to natural sound sources recorded at different positions. Obtained tuning curves match well tuning characteristics of neurons in the mammalian auditory cortex. This study connects neuronal coding of the auditory space with natural stimulus statistics and generates new experimental predictions. Moreover, results presented here suggest that cortical regions with seemingly different functions may implement the same computational strategy-efficient coding. PMID:25996373

  4. Functional segregation of monaural and binaural selectivity in the pallid bat auditory cortex.

    PubMed

    Razak, Khaleel A

    2016-07-01

    Different fields of the auditory cortex can be distinguished by the extent and level tolerance of spatial selectivity. The mechanisms underlying the range of spatial tuning properties observed across cortical fields are unclear. Here, this issue was addressed in the pallid bat because its auditory cortex contains two segregated regions of response selectivity that serve two different behaviors: echolocation for obstacle avoidance and localization of prey-generated noise. This provides the unique opportunity to examine mechanisms of spatial properties in two functionally distinct regions. Previous studies have shown that spatial selectivity of neurons in the region selective for noise (noise-selective region, NSR) is level tolerant and shaped by interaural level difference (ILD) selectivity. In contrast, spatial selectivity of neurons in the echolocation region ('FM sweep-selective region' or FMSR) is strongly level dependent with many neurons responding to multiple distinct spatial locations for louder sounds. To determine the mechanisms underlying such level dependence, frequency, azimuth, rate-level responses and ILD selectivity were measured from the same FMSR neurons. The majority (∼75%) of FMSR neurons were monaural (ILD insensitive). Azimuth tuning curves expanded or split into multiple peaks with increasing sound level in a manner that was predicted by the rate-level response of neurons. These data suggest that azimuth selectivity of FMSR neurons depends more on monaural ear directionality and rate-level responses. The pallid bat cortex utilizes segregated monaural and binaural regions to process echoes and prey-generated noise. Together the pallid bat FMSR/NSR data provide mechanistic explanations for a broad range of spatial tuning properties seen across species. PMID:27233917

  5. The Opponent Channel Population Code of Sound Location Is an Efficient Representation of Natural Binaural Sounds

    PubMed Central

    Młynarski, Wiktor

    2015-01-01

    In mammalian auditory cortex, sound source position is represented by a population of broadly tuned neurons whose firing is modulated by sounds located at all positions surrounding the animal. Peaks of their tuning curves are concentrated at lateral position, while their slopes are steepest at the interaural midline, allowing for the maximum localization accuracy in that area. These experimental observations contradict initial assumptions that the auditory space is represented as a topographic cortical map. It has been suggested that a “panoramic” code has evolved to match specific demands of the sound localization task. This work provides evidence suggesting that properties of spatial auditory neurons identified experimentally follow from a general design principle- learning a sparse, efficient representation of natural stimuli. Natural binaural sounds were recorded and served as input to a hierarchical sparse-coding model. In the first layer, left and right ear sounds were separately encoded by a population of complex-valued basis functions which separated phase and amplitude. Both parameters are known to carry information relevant for spatial hearing. Monaural input converged in the second layer, which learned a joint representation of amplitude and interaural phase difference. Spatial selectivity of each second-layer unit was measured by exposing the model to natural sound sources recorded at different positions. Obtained tuning curves match well tuning characteristics of neurons in the mammalian auditory cortex. This study connects neuronal coding of the auditory space with natural stimulus statistics and generates new experimental predictions. Moreover, results presented here suggest that cortical regions with seemingly different functions may implement the same computational strategy-efficient coding. PMID:25996373

  6. Vocal behavior and vocal loading factors for preschool teachers at work studied with binaural DAT recordings.

    PubMed

    Södersten, Maria; Granqvist, Svante; Hammarberg, Britta; Szabo, Annika

    2002-09-01

    Preschool teachers are at risk for developing voice problems such as vocal fatigue and vocal nodules. The purpose of this report was to study preschool teachers' voice use during work. Ten healthy female preschool teachers working at daycare centers (DCC) served as subjects. A binaural recording technique was used. Two microphones were placed on both sides of the subject's head, at equal distance from the mouth, and a portable DAT recorder was attached to the subject's waist. Recordings were made of a standard reading passage before work (baseline) and of spontaneous speech during work. The recording technique allowed separate analyses of the level of the background noise, and of the subjects' voice sound pressure level, mean fundamental frequency, and total phonation time. Among the results, mean background noise level for the ten DCCs was 76.1 dBA (range 73.0-78.2), which is more than 20 dB higher than what is recommended where speech communication is important (50-55 dBA). The subjects spoke on an average of 9.1 dB louder (p < 0.0001), and with higher mean fundamental frequency (247 Hz) during work as compared to the baseline (202 Hz) (p < 0.0001). Mean phonation time for the group was 17%, which was considered high. It was concluded that preschool teachers do have a highly vocally demanding profession. Important steps to reduce the vocal loading for this occupation would be to decrease the background noise levels and include pauses so that preschool teachers can rest their voices. PMID:12395988

  7. Amplitude modulation detection by human listeners in reverberant sound fields: Carrier bandwidth effects and binaural versus monaural comparison

    PubMed Central

    Zahorik, Pavel; Kim, Duck O.; Kuwada, Shigeyuki; Anderson, Paul W.; Brandewie, Eugene; Collecchia, Regina; Srinivasan, Nirmal

    2012-01-01

    Previous work [Zahorik et al., POMA, 12, 050005 (2011)] has reported that for a broadband noise carrier signal in a simulated reverberant sound field, human sensitivity to amplitude modulation (AM) is higher than would be predicted based on the broadband acoustical modulation transfer function (MTF) of the listening environment. Interpretation of this result was complicated by the fact that acoustical MTFs of rooms are often quite different for different carrier frequency regions, and listeners may have selectively responded to advantageous carrier frequency regions where the effective acoustic modulation loss due to the room was less than indicated by a broadband acoustic MTF analysis. Here, AM sensitivity testing and acoustic MTF analyses were expanded to include narrowband noise carriers (1-octave and 1/3-octave bands centered at 4 kHz), as well as monaural and binaural listening conditions. Narrowband results were found to be consistent with broadband results: In a reverberant sound field, human AM sensitivity is higher than indicated by the acoustical MTFs. The effect was greatest for modulation frequencies above 32 Hz and was present whether the stimulation was monaural or binaural. These results are suggestive of mechanisms that functionally enhance modulation in reverberant listening. PMID:23437416

  8. The binaural performance of a cross-talk cancellation system with matched or mismatched setup and playback acoustics

    PubMed Central

    Akeroyd, Michael A.; Chambers, John; Bullock, David; Palmer, Alan R.; Summerfield, A. Quentin; Nelson, Philip A.; Gatehouse, Stuart

    2013-01-01

    Cross-talk cancellation is a method for synthesising virtual auditory space using loudspeakers. One implementation is the “Optimal Source Distribution” technique [T. Takeuchi and P. Nelson, J. Acoust. Soc. Am. 112, 2786-2797 (2002)], in which the audio bandwidth is split across three pairs of loudspeakers, placed at azimuths of ±90°, ±15°, and ±3°, conveying low, mid and high frequencies, respectively. A computational simulation of this system was developed and verified against measurements made on an acoustic system using a manikin. Both the acoustic system and the simulation gave a wideband average cancellation of almost 25 dB. The simulation showed that when there was a mismatch between the head-related transfer functions used to set up the system and those of the final listener, the cancellation was reduced to an average of 13 dB. Moreover, in this case the binaural ITDs and ILDs delivered by the simulation of the OSD system often differed from the target values. It is concluded that only when the OSD system is set up with “matched” head-related transfer functions can it deliver accurate binaural cues. PMID:17348528

  9. The role of spectral detail in the binaural transfer function on perceived externalization in a reverberant environment.

    PubMed

    Hassager, Henrik Gert; Gran, Fredrik; Dau, Torsten

    2016-05-01

    Individual binaural room impulse responses (BRIRs) were recorded at a distance of 1.5 m for azimuth angles of 0° and 50° in a reverberant room. Spectral details were reduced in either the direct or the reverberant part of the BRIRs by averaging the magnitude responses with band-pass filters. For various filter bandwidths, the modified BRIRs were convolved with broadband noise and listeners judged the perceived position of the noise when virtualized over headphones. Only reductions in spectral details of the direct part obtained with filter bandwidths broader than one equivalent rectangular bandwidth affected externalization. Reductions in spectral details of the reverberant part had only little influence on externalization. In both conditions, externalization was not as pronounced at 0° as at 50°. To characterize the auditory processes that may be involved in the perception of externalization, a quantitative model is proposed. The model includes an echo-suppression mechanism, a filterbank describing the frequency selectivity in the cochlea and a binaural stage that measures the deviations of the interaural level differences between the considered input and the unmodified input. These deviations, integrated across frequency, are then mapped to a value that corresponds to the perceived externalization. PMID:27250190

  10. Predicting binaural speech intelligibility using the signal-to-noise ratio in the envelope power spectrum domain.

    PubMed

    Chabot-Leclerc, Alexandre; MacDonald, Ewen N; Dau, Torsten

    2016-07-01

    This study proposes a binaural extension to the multi-resolution speech-based envelope power spectrum model (mr-sEPSM) [Jørgensen, Ewert, and Dau (2013). J. Acoust. Soc. Am. 134, 436-446]. It consists of a combination of better-ear (BE) and binaural unmasking processes, implemented as two monaural realizations of the mr-sEPSM combined with a short-term equalization-cancellation process, and uses the signal-to-noise ratio in the envelope domain (SNRenv) as the decision metric. The model requires only two parameters to be fitted per speech material and does not require an explicit frequency weighting. The model was validated against three data sets from the literature, which covered the following effects: the number of maskers, the masker types [speech-shaped noise (SSN), speech-modulated SSN, babble, and reversed speech], the masker(s) azimuths, reverberation on the target and masker, and the interaural time difference of the target and masker. The Pearson correlation coefficient between the simulated speech reception thresholds and the data across all experiments was 0.91. A model version that considered only BE processing performed similarly (correlation coefficient of 0.86) to the complete model, suggesting that BE processing could be considered sufficient to predict intelligibility in most realistic conditions. PMID:27475146

  11. The Binaural Masking-Level Difference of Mandarin Tone Detection and the Binaural Intelligibility-Level Difference of Mandarin Tone Recognition in the Presence of Speech-Spectrum Noise

    PubMed Central

    Ho, Cheng-Yu; Li, Pei-Chun; Chiang, Yuan-Chuan; Young, Shuenn-Tsong; Chu, Woei-Chyn

    2015-01-01

    Binaural hearing involves using information relating to the differences between the signals that arrive at the two ears, and it can make it easier to detect and recognize signals in a noisy environment. This phenomenon of binaural hearing is quantified in laboratory studies as the binaural masking-level difference (BMLD). Mandarin is one of the most commonly used languages, but there are no publication values of BMLD or BILD based on Mandarin tones. Therefore, this study investigated the BMLD and BILD of Mandarin tones. The BMLDs of Mandarin tone detection were measured based on the detection threshold differences for the four tones of the voiced vowels /i/ (i.e., /i1/, /i2/, /i3/, and /i4/) and /u/ (i.e., /u1/, /u2/, /u3/, and /u4/) in the presence of speech-spectrum noise when presented interaurally in phase (S0N0) and interaurally in antiphase (SπN0). The BILDs of Mandarin tone recognition in speech-spectrum noise were determined as the differences in the target-to-masker ratio (TMR) required for 50% correct tone recognitions between the S0N0 and SπN0 conditions. The detection thresholds for the four tones of /i/ and /u/ differed significantly (p<0.001) between the S0N0 and SπN0 conditions. The average detection thresholds of Mandarin tones were all lower in the SπN0 condition than in the S0N0 condition, and the BMLDs ranged from 7.3 to 11.5 dB. The TMR for 50% correct Mandarin tone recognitions differed significantly (p<0.001) between the S0N0 and SπN0 conditions, at –13.4 and –18.0 dB, respectively, with a mean BILD of 4.6 dB. The study showed that the thresholds of Mandarin tone detection and recognition in the presence of speech-spectrum noise are improved when phase inversion is applied to the target speech. The average BILDs of Mandarin tones are smaller than the average BMLDs of Mandarin tones. PMID:25835987

  12. Capturing Callisto

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons Long Range Reconnaissance Imager (LORRI) captured these two images of Jupiter's outermost large moon, Callisto, as the spacecraft flew past Jupiter in late February. New Horizons' closest approach distance to Jupiter was 2.3 million kilometers (1.4 million miles), not far outside Callisto's orbit, which has a radius of 1.9 million kilometers (1.2 million miles). However, Callisto happened to be on the opposite side of Jupiter during the spacecraft's pass through the Jupiter system, so these images, taken from 4.7 million kilometers (3.0 million miles) and 4.2 million kilometers (2.6 million miles) away, are the closest of Callisto that New Horizons obtained.

    Callisto's ancient, crater-scarred surface makes it very different from its three more active sibling satellites, Io, Europa and Ganymede. Callisto, 4,800 kilometers (3000 miles) in diameter, displays no large-scale geological features other than impact craters, and every bright spot in these images is a crater. The largest impact feature on Callisto, the huge basin Valhalla, is visible as a bright patch at the 10 o'clock position. The craters are bright because they have excavated material relatively rich in water ice from beneath the dark, dusty material that coats most of the surface.

    The two images show essentially the same side of Callisto -- the side that faces Jupiter -- under different illumination conditions. The images accompanied scans of Callisto's infrared spectrum with New Horizons' Linear Etalon Imaging Spectral Array (LEISA). The New Horizons science team designed these scans to study how the infrared spectrum of Callisto's water ice changes as lighting and viewing conditions change, and as the ice cools through Callisto's late afternoon. The infrared spectrum of water ice depends slightly on its temperature, and a goal of New Horizons when it reaches the Pluto system (in 2015) is to use the water ice features in the spectrum of Pluto's moon Charon, and

  13. A Binaural Cochlear Implant Sound Coding Strategy Inspired by the Contralateral Medial Olivocochlear Reflex

    PubMed Central

    Eustaquio-Martín, Almudena; Stohl, Joshua S.; Wolford, Robert D.; Schatzer, Reinhold; Wilson, Blake S.

    2016-01-01

    Objectives: In natural hearing, cochlear mechanical compression is dynamically adjusted via the efferent medial olivocochlear reflex (MOCR). These adjustments probably help understanding speech in noisy environments and are not available to the users of current cochlear implants (CIs). The aims of the present study are to: (1) present a binaural CI sound processing strategy inspired by the control of cochlear compression provided by the contralateral MOCR in natural hearing; and (2) assess the benefits of the new strategy for understanding speech presented in competition with steady noise with a speech-like spectrum in various spatial configurations of the speech and noise sources. Design: Pairs of CI sound processors (one per ear) were constructed to mimic or not mimic the effects of the contralateral MOCR on compression. For the nonmimicking condition (standard strategy or STD), the two processors in a pair functioned similarly to standard clinical processors (i.e., with fixed back-end compression and independently of each other). When configured to mimic the effects of the MOCR (MOC strategy), the two processors communicated with each other and the amount of back-end compression in a given frequency channel of each processor in the pair decreased/increased dynamically (so that output levels dropped/increased) with increases/decreases in the output energy from the corresponding frequency channel in the contralateral processor. Speech reception thresholds in speech-shaped noise were measured for 3 bilateral CI users and 2 single-sided deaf unilateral CI users. Thresholds were compared for the STD and MOC strategies in unilateral and bilateral listening conditions and for three spatial configurations of the speech and noise sources in simulated free-field conditions: speech and noise sources colocated in front of the listener, speech on the left ear with noise in front of the listener, and speech on the left ear with noise on the right ear. In both bilateral and

  14. Behavioural sensitivity to binaural spatial cues in ferrets: evidence for plasticity in the duplex theory of sound localization

    PubMed Central

    Keating, Peter; Nodal, Fernando R; King, Andrew J

    2014-01-01

    For over a century, the duplex theory has guided our understanding of human sound localization in the horizontal plane. According to this theory, the auditory system uses interaural time differences (ITDs) and interaural level differences (ILDs) to localize low-frequency and high-frequency sounds, respectively. Whilst this theory successfully accounts for the localization of tones by humans, some species show very different behaviour. Ferrets are widely used for studying both clinical and fundamental aspects of spatial hearing, but it is not known whether the duplex theory applies to this species or, if so, to what extent the frequency range over which each binaural cue is used depends on acoustical or neurophysiological factors. To address these issues, we trained ferrets to lateralize tones presented over earphones and found that the frequency dependence of ITD and ILD sensitivity broadly paralleled that observed in humans. Compared with humans, however, the transition between ITD and ILD sensitivity was shifted toward higher frequencies. We found that the frequency dependence of ITD sensitivity in ferrets can partially be accounted for by acoustical factors, although neurophysiological mechanisms are also likely to be involved. Moreover, we show that binaural cue sensitivity can be shaped by experience, as training ferrets on a 1-kHz ILD task resulted in significant improvements in thresholds that were specific to the trained cue and frequency. Our results provide new insights into the factors limiting the use of different sound localization cues and highlight the importance of sensory experience in shaping the underlying neural mechanisms. PMID:24256073

  15. Effect of monaural and binaural stimulation on cytoplasmic RNA content in cells of the central nucleus of the cat inferior colliculus.

    PubMed

    Shmigidina, G N

    1981-01-01

    A cytophotometric study of sections stained with gallocyanin and chrome alum showed that monaural stimulation for 2 h and binaural stimulation for 1.5 h with rhythmic noise signals led to a marked increase in the cytoplasmic RNA content per cell in the principal and large multipolar neurons of the dorsal and ventral parts of the ventrolateral region of the central nucleus of the inferior colliculus. The increase in cytoplasmic RNA content in the principal cells of the ipsi- and contralateral parts of this nucleus relative to the stimulated ear in the case of monaural stimulation and the increase in RNA content in response to binaural stimulation suggests a uniform distribution of bilaterally converging connections from the lower nuclei of the auditory system on the principal cells. The increase in cytoplasmic RNA in the large multipolar cells of the contralateral central nucleus in response to monaural stimulation is evidence of the predominantly contralateral projection to these cells. The results are evidence of convergence of binaural influences on the principal and large multipolar cells of the central nucleus of the inferior colliculus. PMID:6173796

  16. Binaural interactions develop in the auditory brainstem of children who are deaf: effects of place and level of bilateral electrical stimulation.

    PubMed

    Gordon, Karen A; Salloum, Claire; Toor, Gurvinder S; van Hoesel, Richard; Papsin, Blake C

    2012-03-21

    Bilateral cochlear implants (CIs) might promote development of binaural hearing required to localize sound sources and hear speech in noise for children who are deaf. These hearing skills improve in children implanted bilaterally but remain poorer than normal. We thus questioned whether the deaf and immature human auditory system is able to integrate input delivered from bilateral CIs. Using electrophysiological measures of brainstem activity that include the Binaural Difference (BD), a measure of binaural processing, we showed that a period of unilateral deprivation before bilateral CI use prolonged response latencies but that amplitudes were not significantly affected. Tonotopic organization was retained to some extent as evidenced by an elimination of the BD with large mismatches in place of stimulation between the two CIs. Smaller place mismatches did not affect BD latency or amplitude, indicating that the tonotopic organization of the auditory brainstem is underdeveloped and/or not well used by CI stimulation. Finally, BD amplitudes decreased when the intensity of bilateral stimulation became weighted to one side and this corresponded to a perceptual shift of sound away from midline toward the side of increased intensity. In summary, bilateral CI stimulation is processed by the developing human auditory brainstem leading to perceptual changes in sound location and potentially improving hearing for children who are deaf. PMID:22442083

  17. The observation of theta wave modulation on brain training by 5 Hz-binaural beat stimulation in seven days.

    PubMed

    Yamsa-Ard, Traisak; Wongsawat, Yodchanan

    2015-08-01

    Traditional buddhist meditation method maybe easy for someone with high experience. However, for the beginner, it is very difficult to keep mental concentration with the tradition way for more than 5 minutes. This research aims to observe effect of the new method for meditation in various analysis methods. A piano music mixed with a 5 Hz (theta band enhancement) binaural beat frequency was used to modulate the brain signals continuously for 7 days. Male of the average age of 33.5±3.84 and female of the average age of 28.6±2.49 were participated. All participants were acquired EEGs twice, before the experiment and seven days after the experiment. We also proposed the observations on the changes of absolute powers, relative powers and brain connectivity (coherence) of the participants. After seven days of training, the absolute power, relative power, and coherence were clearly closer to the normative database. We can initially say that the recommended meditation method can efficiently mimic the effect of having the traditional buddhist meditation on enhancing the delta and theta powers in the brain. PMID:26737822

  18. Sound localization in common vampire bats: acuity and use of the binaural time cue by a small mammal.

    PubMed

    Heffner, Rickye S; Koay, Gimseong; Heffner, Henry E

    2015-01-01

    Passive sound-localization acuity and the ability to use binaural time and intensity cues were determined for the common vampire bat (Desmodus rotundus). The bats were tested using a conditioned suppression/avoidance procedure in which they drank defibrinated blood from a spout in the presence of sounds from their right, but stopped drinking (i.e., broke contact with the spout) whenever a sound came from their left, thereby avoiding a mild shock. The mean minimum audible angle for three bats for a 100-ms noise burst was 13.1°-within the range of thresholds for other bats and near the mean for mammals. Common vampire bats readily localized pure tones of 20 kHz and higher, indicating they could use interaural intensity-differences. They could also localize pure tones of 5 kHz and lower, thereby demonstrating the use of interaural time-differences, despite their very small maximum interaural distance of 60 μs. A comparison of the use of locus cues among mammals suggests several implications for the evolution of sound localization and its underlying anatomical and physiological mechanisms. PMID:25618037

  19. Sound localization in common vampire bats: Acuity and use of the binaural time cue by a small mammal

    PubMed Central

    Heffner, Rickye S.; Koay, Gimseong; Heffner, Henry E.

    2015-01-01

    Passive sound-localization acuity and the ability to use binaural time and intensity cues were determined for the common vampire bat (Desmodus rotundus). The bats were tested using a conditioned suppression/avoidance procedure in which they drank defibrinated blood from a spout in the presence of sounds from their right, but stopped drinking (i.e., broke contact with the spout) whenever a sound came from their left, thereby avoiding a mild shock. The mean minimum audible angle for three bats for a 100-ms noise burst was 13.1°—within the range of thresholds for other bats and near the mean for mammals. Common vampire bats readily localized pure tones of 20 kHz and higher, indicating they could use interaural intensity-differences. They could also localize pure tones of 5 kHz and lower, thereby demonstrating the use of interaural time-differences, despite their very small maximum interaural distance of 60 μs. A comparison of the use of locus cues among mammals suggests several implications for the evolution of sound localization and its underlying anatomical and physiological mechanisms. PMID:25618037

  20. A new asymmetric directional microphone algorithm with automatic mode-switching ability for binaural hearing support devices.

    PubMed

    Kim, Jinryoul; Nam, Kyoung Won; Yook, Sunhyun; Jang, Dong Pyo; Kim, In Young; Hong, Sung Hwa

    2015-06-01

    For hearing support devices, it is important to minimize the negative effect of ambient noises for speech recognition but also, at the same time, supply natural ambient sounds to the hearing-impaired person. However, conventional fixed bilateral asymmetric directional microphone (DM) algorithms cannot perform in such a way when the DM-mode device and a dominant noise (DN) source are placed on the same lateral hemisphere. In this study, a new binaural asymmetric DM algorithm that can overcome the defects of conventional algorithms is proposed. The proposed algorithm can estimate the position of a specific DN in the 90°-270° range and switch directional- and omnidirectional-mode devices automatically if the DM-mode device and the DN are placed in opposite lateral hemispheres. Computer simulation and KEMAR mannequin recording tests demonstrated that the performance of the conventional algorithm deteriorated when the DM-mode device and the DN were placed in the opposite hemisphere; in contrast, the performance of the proposed algorithm was consistently maintained regardless of directional variations in the DN. Based on these experimental results, the proposed algorithm may be able to improve speech quality and intelligibility for hearing-impaired persons who have similar degrees of hearing impairment in both ears. PMID:25597956

  1. Video Screen Capture Basics

    ERIC Educational Resources Information Center

    Dunbar, Laura

    2014-01-01

    This article is an introduction to video screen capture. Basic information of two software programs, QuickTime for Mac and BlueBerry Flashback Express for PC, are also discussed. Practical applications for video screen capture are given.

  2. Relating hearing loss and executive functions to hearing aid users' preference for, and speech recognition with, different combinations of binaural noise reduction and microphone directionality.

    PubMed

    Neher, Tobias

    2014-01-01

    Knowledge of how executive functions relate to preferred hearing aid (HA) processing is sparse and seemingly inconsistent with related knowledge for speech recognition outcomes. This study thus aimed to find out if (1) performance on a measure of reading span (RS) is related to preferred binaural noise reduction (NR) strength, (2) similar relations exist for two different, non-verbal measures of executive function, (3) pure-tone average hearing loss (PTA), signal-to-noise ratio (SNR), and microphone directionality (DIR) also influence preferred NR strength, and (4) preference and speech recognition outcomes are similar. Sixty elderly HA users took part. Six HA conditions consisting of omnidirectional or cardioid microphones followed by inactive, moderate, or strong binaural NR as well as linear amplification were tested. Outcome was assessed at fixed SNRs using headphone simulations of a frontal target talker in a busy cafeteria. Analyses showed positive effects of active NR and DIR on preference, and negative and positive effects of, respectively, strong NR and DIR on speech recognition. Also, while moderate NR was the most preferred NR setting overall, preference for strong NR increased with SNR. No relation between RS and preference was found. However, larger PTA was related to weaker preference for inactive NR and stronger preference for strong NR for both microphone modes. Equivalent (but weaker) relations between worse performance on one non-verbal measure of executive function and the HA conditions without DIR were found. For speech recognition, there were relations between HA condition, PTA, and RS, but their pattern differed from that for preference. Altogether, these results indicate that, while moderate NR works well in general, a notable proportion of HA users prefer stronger NR. Furthermore, PTA and executive functions can account for some of the variability in preference for, and speech recognition with, different binaural NR and DIR settings. PMID

  3. Binaural tuning of auditory units in the forebrain archistriatal gaze fields of the barn owl: local organization but no space map.

    PubMed

    Cohen, Y E; Knudsen, E I

    1995-07-01

    We identified a region in the archistriatum of the barn owl forebrain that contains neurons sensitive to auditory stimuli. Nearly all of these neurons are tuned for binaural localization cues. The archistriatum is known to be the primary source of motor-related output from the avian forebrain and, in barn owls, contributes to the control of gaze, much like the frontal eye fields in monkeys. The auditory region is located in the medial portion of the archistriatum, at the level of the anterior commissure, and is within the region of the archistriatum from which head saccades can be elicited by electrical microstimulation (see preceding companion article, Knudsen et al., 1995). Free-field measurements revealed that auditory sites have large, spatial receptive fields. However, within these large receptive fields, responses are tuned sharply for sound source location. Dichotic measurements showed that auditory sites are tuned broadly for frequency and that the majority are tuned to particular values of interaural time differences and interaural level differences, the principal cues used by barn owls for sound localization. The tuning of sites to these binaural cues is essentially independent of sound level. The auditory properties of units in the medial archistriatum are similar to those of units in the optic tectum, a structure that also contributes to gaze control. Unlike the optic tectum, however, the auditory region of the archistriatum does not contain a single, continuous auditory map of space. Instead, it is organized into dorsoventral clusters of sites with similar binaural (spatial) tuning. The different representations of auditory space in closely related structures in the forebrain (archistriatum) and midbrain (optic tectum) probably reflect the fact that the forebrain contributes to a wide variety of sensorimotor tasks more complicated than gaze control. PMID:7623142

  4. Relating hearing loss and executive functions to hearing aid users' preference for, and speech recognition with, different combinations of binaural noise reduction and microphone directionality

    PubMed Central

    Neher, Tobias

    2014-01-01

    Knowledge of how executive functions relate to preferred hearing aid (HA) processing is sparse and seemingly inconsistent with related knowledge for speech recognition outcomes. This study thus aimed to find out if (1) performance on a measure of reading span (RS) is related to preferred binaural noise reduction (NR) strength, (2) similar relations exist for two different, non-verbal measures of executive function, (3) pure-tone average hearing loss (PTA), signal-to-noise ratio (SNR), and microphone directionality (DIR) also influence preferred NR strength, and (4) preference and speech recognition outcomes are similar. Sixty elderly HA users took part. Six HA conditions consisting of omnidirectional or cardioid microphones followed by inactive, moderate, or strong binaural NR as well as linear amplification were tested. Outcome was assessed at fixed SNRs using headphone simulations of a frontal target talker in a busy cafeteria. Analyses showed positive effects of active NR and DIR on preference, and negative and positive effects of, respectively, strong NR and DIR on speech recognition. Also, while moderate NR was the most preferred NR setting overall, preference for strong NR increased with SNR. No relation between RS and preference was found. However, larger PTA was related to weaker preference for inactive NR and stronger preference for strong NR for both microphone modes. Equivalent (but weaker) relations between worse performance on one non-verbal measure of executive function and the HA conditions without DIR were found. For speech recognition, there were relations between HA condition, PTA, and RS, but their pattern differed from that for preference. Altogether, these results indicate that, while moderate NR works well in general, a notable proportion of HA users prefer stronger NR. Furthermore, PTA and executive functions can account for some of the variability in preference for, and speech recognition with, different binaural NR and DIR settings. PMID

  5. Capture Their Attention: Capturing Lessons Using Screen Capture Software

    ERIC Educational Resources Information Center

    Drumheller, Kristina; Lawler, Gregg

    2011-01-01

    When students miss classes for university activities such as athletic and academic events, they inevitably miss important class material. Students can get notes from their peers or visit professors to find out what they missed, but when students miss new and challenging material these steps are sometimes not enough. Screen capture and recording…

  6. Cryogenic Carbon Capture

    SciTech Connect

    2010-07-15

    IMPACCT Project: SES is developing a process to capture CO2 from the exhaust gas of coal-fired power plants by desublimation - the conversion of a gas to a solid. Capturing CO2 as a solid and delivering it as a liquid avoids the large energy cost of CO2 gas compression. SES’ capture technology facilitates the prudent use of available energy resources. Coal is our most abundant energy resource and is an excellent fuel for baseline power production. SES capture technology can capture 99% of the CO2 emissions in addition to a wide range of other pollutants more efficiently and at lower costs than existing capture technologies. SES’ capture technology can be readily added to our existing energy infrastructure.

  7. Blind people are more sensitive than sighted people to binaural sound-location cues, particularly inter-aural level differences.

    PubMed

    Nilsson, Mats E; Schenkman, Bo N

    2016-02-01

    Blind people use auditory information to locate sound sources and sound-reflecting objects (echolocation). Sound source localization benefits from the hearing system's ability to suppress distracting sound reflections, whereas echolocation would benefit from "unsuppressing" these reflections. To clarify how these potentially conflicting aspects of spatial hearing interact in blind versus sighted listeners, we measured discrimination thresholds for two binaural location cues: inter-aural level differences (ILDs) and inter-aural time differences (ITDs). The ILDs or ITDs were present in single clicks, in the leading component of click pairs, or in the lagging component of click pairs, exploiting processes related to both sound source localization and echolocation. We tested 23 blind (mean age = 54 y), 23 sighted-age-matched (mean age = 54 y), and 42 sighted-young (mean age = 26 y) listeners. The results suggested greater ILD sensitivity for blind than for sighted listeners. The blind group's superiority was particularly evident for ILD-lag-click discrimination, suggesting not only enhanced ILD sensitivity in general but also increased ability to unsuppress lagging clicks. This may be related to the blind person's experience of localizing reflected sounds, for which ILDs may be more efficient than ITDs. On the ITD-discrimination tasks, the blind listeners performed better than the sighted age-matched listeners, but not better than the sighted young listeners. ITD sensitivity declines with age, and the equal performance of the blind listeners compared to a group of substantially younger listeners is consistent with the notion that blind people's experience may offset age-related decline in ITD sensitivity. PMID:26433052

  8. Predicting binaural responses from monaural responses in the gerbil medial superior olive.

    PubMed

    Plauška, Andrius; Borst, J Gerard; van der Heijden, Marcel

    2016-06-01

    Accurate sound source localization of low-frequency sounds in the horizontal plane depends critically on the comparison of arrival times at both ears. A specialized brainstem circuit containing the principal neurons of the medial superior olive (MSO) is dedicated to this comparison. MSO neurons are innervated by segregated inputs from both ears. The coincident arrival of excitatory inputs from both ears is thought to trigger action potentials, with differences in internal delays creating a unique sensitivity to interaural time differences (ITDs) for each cell. How the inputs from both ears are integrated by the MSO neurons is still debated. Using juxtacellular recordings, we tested to what extent MSO neurons from anesthetized Mongolian gerbils function as simple cross-correlators of their bilateral inputs. From the measured subthreshold responses to monaural wideband stimuli we predicted the rate-ITD functions obtained from the same MSO neuron, which have a damped oscillatory shape. The rate of the oscillations and the position of the peaks and troughs were accurately predicted. The amplitude ratio between dominant and secondary peaks of the rate-ITD function, captured in the width of its envelope, was not always exactly reproduced. This minor imperfection pointed to the methodological limitation of using a linear representation of the monaural inputs, which disregards any temporal sharpening occurring in the cochlear nucleus. The successful prediction of the major aspects of rate-ITD curves supports a simple scheme in which the ITD sensitivity of MSO neurons is realized by the coincidence detection of excitatory monaural inputs. PMID:27009164

  9. Overriding auditory attentional capture.

    PubMed

    Dalton, Polly; Lavie, Nilli

    2007-02-01

    Attentional capture by color singletons during shape search can be eliminated when the target is not a feature singleton (Bacon & Egeth, 1994). This suggests that a "singleton detection" search strategy must be adopted for attentional capture to occur. Here we find similar effects on auditory attentional capture. Irrelevant high-intensity singletons interfered with an auditory search task when the target itself was also a feature singleton. However, singleton interference was eliminated when the target was not a singleton (i.e., when nontargets were made heterogeneous, or when more than one target sound was presented). These results suggest that auditory attentional capture depends on the observer's attentional set, as does visual attentional capture. The suggestion that hearing might act as an early warning system that would always be tuned to unexpected unique stimuli must therefore be modified to accommodate these strategy-dependent capture effects. PMID:17557587

  10. Testing the Capture Magnet

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image of a model capture magnet was taken after an experiment in a Mars simulation chamber at the University of Aarhus, Denmark. It has some dust on it, but not as much as that on the Mars Exploration Rover Spirit's capture magnet. The capture and filter magnets on both Mars Exploration Rovers were delivered by the magnetic properties team at the Center for Planetary Science, Copenhagen, Denmark.

  11. Spatial capture-recapture

    USGS Publications Warehouse

    Royle, J. Andrew; Chandler, Richard B.; Sollmann, Rahel; Gardner, Beth

    2013-01-01

    Spatial Capture-Recapture provides a revolutionary extension of traditional capture-recapture methods for studying animal populations using data from live trapping, camera trapping, DNA sampling, acoustic sampling, and related field methods. This book is a conceptual and methodological synthesis of spatial capture-recapture modeling. As a comprehensive how-to manual, this reference contains detailed examples of a wide range of relevant spatial capture-recapture models for inference about population size and spatial and temporal variation in demographic parameters. Practicing field biologists studying animal populations will find this book to be a useful resource, as will graduate students and professionals in ecology, conservation biology, and fisheries and wildlife management.

  12. Improving speech-in-noise recognition for children with hearing loss: Potential effects of language abilities, binaural summation, and head shadow

    PubMed Central

    Nittrouer, Susan; Caldwell-Tarr, Amanda; Tarr, Eric; Lowenstein, Joanna H.; Rice, Caitlin; Moberly, Aaron C.

    2014-01-01

    Objective: This study examined speech recognition in noise for children with hearing loss, compared it to recognition for children with normal hearing, and examined mechanisms that might explain variance in children’s abilities to recognize speech in noise. Design: Word recognition was measured in two levels of noise, both when the speech and noise were co-located in front and when the noise came separately from one side. Four mechanisms were examined as factors possibly explaining variance: vocabulary knowledge, sensitivity to phonological structure, binaural summation, and head shadow. Study sample: Participants were 113 eight-year-old children. Forty-eight had normal hearing (NH) and 65 had hearing loss: 18 with hearing aids (HAs), 19 with one cochlear implant (CI), and 28 with two CIs. Results: Phonological sensitivity explained a significant amount of between-groups variance in speech-in-noise recognition. Little evidence of binaural summation was found. Head shadow was similar in magnitude for children with NH and with CIs, regardless of whether they wore one or two CIs. Children with HAs showed reduced head shadow effects. Conclusion: These outcomes suggest that in order to improve speech-in-noise recognition for children with hearing loss, intervention needs to be comprehensive, focusing on both language abilities and auditory mechanisms. PMID:23834373

  13. Intelsat VI Capture Attempt

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The first single crewmember EVA capture attempt of the Intelsat VI as seen from Endeavour's aft flight deck windows. EVA Mission Specialist Pierre Thuot standing on the Remote Manipulator System (RMS) end effector platform, with the satellite capture bar attempting to attach it to the free floating communications satellite.

  14. Demonstrating carbon capture

    SciTech Connect

    Qader, A.; Hooper, B.; Stevens, G.

    2009-11-15

    Australia is at the forefront of advancing CCS technology. The CO2CRC's H3 (Post-combustion) and Mulgrave (pre-combustion) capture projects are outlined. The capture technologies for these 2 demonstration projects are described. 1 map., 2 photos.

  15. Structure-based modeling of head-related transfer functions towards interactive customization of binaural sound systems

    NASA Astrophysics Data System (ADS)

    Gupta, Navarun

    2003-10-01

    One of the most popular techniques for creating spatialized virtual sounds is based on the use of Head-Related Transfer Functions (HRTFs). HRTFs are signal processing models that represent the modifications undergone by the acoustic signal as it travels from a sound source to each of the listener's eardrums. These modifications are due to the interaction of the acoustic waves with the listener's torso, shoulders, head and pinnae, or outer ears. As such, HRTFs are somewhat different for each listener. For a listener to perceive synthesized 3-D sound cues correctly, the synthesized cues must be similar to the listener's own HRTFs. One can measure individual HRTFs using specialized recording systems, however, these systems are prohibitively expensive and restrict the portability of the 3-D sound system. HRTF-based systems also face several computational challenges. This dissertation presents an alternative method for the synthesis of binaural spatialized sounds. The sound entering the pinna undergoes several reflective, diffractive and resonant phenomena, which determine the HRTF. Using signal processing tools, such as Prony's signal modeling method, an appropriate set of time delays and a resonant frequency were used to approximate the measured Head-Related Impulse Responses (HRIRs). Statistical analysis was used to find out empirical equations describing how the reflections and resonances are determined by the shape and size of the pinna features obtained from 3D images of 15 experimental subjects modeled in the project. These equations were used to yield "Model HRTFs" that can create elevation effects. Listening tests conducted on 10 subjects show that these model HRTFs are 5% more effective than generic HRTFs when it comes to localizing sounds in the frontal plane. The number of reversals (perception of sound source above the horizontal plane when actually it is below the plane and vice versa) was also reduced by 5.7%, showing the perceptual effectiveness of this

  16. IMPACCT: Carbon Capture Technology

    SciTech Connect

    2012-01-01

    IMPACCT Project: IMPACCT’s 15 projects seek to develop technologies for existing coal-fired power plants that will lower the cost of carbon capture. Short for “Innovative Materials and Processes for Advanced Carbon Capture Technologies,” the IMPACCT Project is geared toward minimizing the cost of removing carbon dioxide (CO2) from coal-fired power plant exhaust by developing materials and processes that have never before been considered for this application. Retrofitting coal-fired power plants to capture the CO2 they produce would enable greenhouse gas reductions without forcing these plants to close, shifting away from the inexpensive and abundant U.S. coal supply.

  17. Intense and specialized dendritic localization of the fragile X mental retardation protein in binaural brainstem neurons: a comparative study in the alligator, chicken, gerbil, and human.

    PubMed

    Wang, Yuan; Sakano, Hitomi; Beebe, Karisa; Brown, Maile R; de Laat, Rian; Bothwell, Mark; Kulesza, Randy J; Rubel, Edwin W

    2014-06-15

    Neuronal dendrites are structurally and functionally dynamic in response to changes in afferent activity. The fragile X mental retardation protein (FMRP) is an mRNA binding protein that regulates activity-dependent protein synthesis and morphological dynamics of dendrites. Loss and abnormal expression of FMRP occur in fragile X syndrome (FXS) and some forms of autism spectrum disorders. To provide further understanding of how FMRP signaling regulates dendritic dynamics, we examined dendritic expression and localization of FMRP in the reptilian and avian nucleus laminaris (NL) and its mammalian analogue, the medial superior olive (MSO), in rodents and humans. NL/MSO neurons are specialized for temporal processing of low-frequency sounds for binaural hearing, which is impaired in FXS. Protein BLAST analyses first demonstrate that the FMRP amino acid sequences in the alligator and chicken are highly similar to human FMRP with identical mRNA-binding and phosphorylation sites, suggesting that FMRP functions similarly across vertebrates. Immunocytochemistry further reveals that NL/MSO neurons have very high levels of dendritic FMRP in low-frequency hearing vertebrates including alligator, chicken, gerbil, and human. Remarkably, dendritic FMRP in NL/MSO neurons often accumulates at branch points and enlarged distal tips, loci known to be critical for branch-specific dendritic arbor dynamics. These observations support an important role for FMRP in regulating dendritic properties of binaural neurons that are essential for low-frequency sound localization and auditory scene segregation, and support the relevance of studying this regulation in nonhuman vertebrates that use low frequencies in order to further understand human auditory processing disorders. PMID:24318628

  18. Contingent Attentional Capture

    NASA Technical Reports Server (NTRS)

    Remington, Roger; Folk, Charles L.

    1994-01-01

    Four experiments address the degree of top-down selectivity in attention capture by feature singletons through manipulations of the spatial relationship and featural similarity of target and distractor singletons in a modified spatial cuing paradigm. Contrary to previous studies, all four experiments show that when searching for a singleton target, an irrelevant featural singleton captures attention only when defined by the same feature value as the target. Experiments 2, 3, and 4 provide a potential explanation for this empirical discrepancy by showing that irrelevant singletons can produce distraction effects that are independent of shifts of spatial attention. The results further support the notion that attentional capture is contingent on top-down attention control settings but indicates that such settings can be instantiated at the level of feature values.

  19. Spatial Knowledge Capture Library

    Energy Science and Technology Software Center (ESTSC)

    2005-05-16

    The Spatial Knowledge Capture Library is a set of algorithms to capture regularities in shapes and trajectories through space and time. We have applied Spatial Knowledge Capture to model the actions of human experts in spatial domains, such as an AWACS Weapons Director task simulation. The library constructs a model to predict the expert’s response to sets of changing cues, such as the movements and actions of adversaries on a battlefield, The library includes amore » highly configurable feature extraction functionality, which supports rapid experimentation to discover causative factors. We use k-medoid clustering to group similar episodes of behavior, and construct a Markov model of system state transitions induced by agents’ actions.« less

  20. AKM capture device

    NASA Technical Reports Server (NTRS)

    Harwell, William D.

    1987-01-01

    In an effort to recover the Westar and Palapa satellites and the considerable investment each represented, NASA and Hughes undertook the Satellite Retrieval Mission. The mechanism used to capture each of the errant satellites was the AKM (Apogee Kick Motor) Capture Device (ACD), also referred to as the Stinger. The ACD had three interface requirements: interface with the Manned Maneuvering Unit (MMU) for transportation to and stabilization of the spacecrafts; interface with each satellite for retrieval; and finally, interface with the Shuttle's Remote Manipulator System (RMS or robot arm) for satellite transport back to the Orbiter's payload bay. The majority of the design requirements were associated with the capture and release of the satellites. In addition to these unique requirements, the general EVA, RMS grapple, and RMS manipulation requirements applied. These requirements included thermal, glare, snag, RMS runaway and crewman safety considerations.

  1. US Spacesuit Knowledge Capture

    NASA Technical Reports Server (NTRS)

    Chullen, Cinda; Thomas, Ken; McMann, Joe; Dolan, Kristi; Bitterly, Rose; Lewis, Cathleen

    2011-01-01

    The ability to learn from both the mistakes and successes of the past is vital to assuring success in the future. Due to the close physical interaction between spacesuit systems and human beings as users, spacesuit technology and usage lends itself rather uniquely to the benefits realized from the skillful organization of historical information; its dissemination; the collection and identification of artifacts; and the education of those in the field. The National Aeronautics and Space Administration (NASA), other organizations and individuals have been performing United States (U.S.) Spacesuit Knowledge Capture since the beginning of space exploration. Avenues used to capture the knowledge have included publication of reports; conference presentations; specialized seminars; and classes usually given by veterans in the field. More recently the effort has been more concentrated and formalized whereby a new avenue of spacesuit knowledge capture has been added to the archives in which videotaping occurs engaging both current and retired specialists in the field presenting technical scope specifically for education and preservation of knowledge. With video archiving, all these avenues of learning can now be brought to life with the real experts presenting their wealth of knowledge on screen for future learners to enjoy. Scope and topics of U.S. spacesuit knowledge capture have included lessons learned in spacesuit technology, experience from the Gemini, Apollo, Skylab and Shuttle programs, hardware certification, design, development and other program components, spacesuit evolution and experience, failure analysis and resolution, and aspects of program management. Concurrently, U.S. spacesuit knowledge capture activities have progressed to a level where NASA, the National Air and Space Museum (NASM), Hamilton Sundstrand (HS) and the spacesuit community are now working together to provide a comprehensive closed-looped spacesuit knowledge capture system which includes

  2. Neutron capture therapies

    SciTech Connect

    Yanch, J.C.; Shefer, R.E.; Klinkowstein, R.E.

    1999-11-02

    In one embodiment there is provided an application of the {sup 10}B(n,{alpha}){sup 7}Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  3. Neutron capture therapies

    SciTech Connect

    Yanch, Jacquelyn C.; Shefer, Ruth E.; Klinkowstein, Robert E.

    1999-01-01

    In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  4. Attention Capture by Faces

    ERIC Educational Resources Information Center

    Langton, Stephen R. H.; Law, Anna S.; Burton, A. Mike; Schweinberger, Stefan R.

    2008-01-01

    We report three experiments that investigate whether faces are capable of capturing attention when in competition with other non-face objects. In Experiment 1a participants took longer to decide that an array of objects contained a butterfly target when a face appeared as one of the distracting items than when the face did not appear in the array.…

  5. Resistance gene capture.

    PubMed

    Rowe-Magnus, D A; Mazel, D

    1999-10-01

    Integrons are the primary mechanism for antibiotic-resistance gene capture and dissemination among Gram-negative bacteria. The recent finding of super-integron structures in the genomes of several bacterial species has expanded their role in genome evolution and suggests that they are the source of mobile multi-resistant integrons. PMID:10508722

  6. Carbon Smackdown: Carbon Capture

    ScienceCinema

    Jeffrey Long

    2010-09-01

    In this July 9, 2010 Berkeley Lab summer lecture, Lab scientists Jeff Long of the Materials Sciences and Nancy Brown of the Environmental Energy Technologies Division discuss their efforts to fight climate change by capturing carbon from the flue gas of power plants, as well as directly from the air

  7. Capturing the Market

    ERIC Educational Resources Information Center

    Ramaswami, Rama

    2009-01-01

    Digital lecture capture and broadcast solutions have been around for only about 10 years, but are poised for healthy growth. Frost & Sullivan research analysts estimate that the market (which amounts to $25 million currently) will quadruple by 2013. It's still dominated by a few key players, however: Sonic Foundry holds a hefty 40 percent-plus…

  8. Carbon Smackdown: Carbon Capture

    SciTech Connect

    Jeffrey Long

    2010-07-12

    In this July 9, 2010 Berkeley Lab summer lecture, Lab scientists Jeff Long of the Materials Sciences and Nancy Brown of the Environmental Energy Technologies Division discuss their efforts to fight climate change by capturing carbon from the flue gas of power plants, as well as directly from the air

  9. Advanced Telemetry Data Capturing

    SciTech Connect

    Paschke, G.A.

    2000-05-16

    This project developed a new generation or advanced data capturing process specifically designed for use in future telemetry test systems at the Kansas City Plant (KCP). Although similar data capturing processes are performed both commercially and at other DOE weapon facilities, the equipment used is not specifically designed to perform acceptance testing requirements unique to the KCP. Commercially available equipment, despite very high cost (up to $125,000), is deficient in reliability and long-term maintainability necessary in test systems at this facility. There are no commercial sources for some requirements, specifically Terminal Data Analyzer (TDA) data processing. Although other custom processes have been developed to satisfy these test requirements, these designs have become difficult to maintain and upgrade.

  10. Target activated frame capture

    NASA Astrophysics Data System (ADS)

    Roberts, G. Marlon; Fitzgerald, James; McCormack, Michael; Steadman, Robert

    2008-04-01

    Over the past decade, technological advances have enabled the use of increasingly intelligent systems for battlefield surveillance. These systems are triggered by a combination of external devices including acoustic and seismic sensors. Such products are mainly used to detect vehicles and personnel. These systems often use infra-red imagery to record environmental information, but Textron Defense Systems' Terrain Commander is one of a small number of systems which analyze these images for the presence of targets. The Terrain Commander combines acoustic, infrared, magnetic, seismic, and visible spectrum sensors to detect nearby targets in military scenarios. When targets are detected by these sensors, the cameras are triggered and images are captured in the infrared and visible spectrum. In this paper we discuss a method through which such systems can perform target tracking in order to record and transmit only the most pertinent surveillance images. This saves bandwidth which is crucial because these systems often use communication systems with throughputs below 2400bps. This method is expected to be executable on low-power processors at frame rates exceeding 10HZ. We accomplish this by applying target activated frame capture algorithms to infra-red video data. The target activated frame capture algorithms combine edge detection and motion detection to determine the best frames to be transmitted to the end user. This keeps power consumption and bandwidth requirements low. Finally, the results of the algorithm are analyzed.

  11. Capturing nature's diversity.

    PubMed

    Pascolutti, Mauro; Campitelli, Marc; Nguyen, Bao; Pham, Ngoc; Gorse, Alain-Dominique; Quinn, Ronald J

    2015-01-01

    Natural products are universally recognized to contribute valuable chemical diversity to the design of molecular screening libraries. The analysis undertaken in this work, provides a foundation for the generation of fragment screening libraries that capture the diverse range of molecular recognition building blocks embedded within natural products. Physicochemical properties were used to select fragment-sized natural products from a database of known natural products (Dictionary of Natural Products). PCA analysis was used to illustrate the positioning of the fragment subset within the property space of the non-fragment sized natural products in the dataset. Structural diversity was analysed by three distinct methods: atom function analysis, using pharmacophore fingerprints, atom type analysis, using radial fingerprints, and scaffold analysis. Small pharmacophore triplets, representing the range of chemical features present in natural products that are capable of engaging in molecular interactions with small, contiguous areas of protein binding surfaces, were analysed. We demonstrate that fragment-sized natural products capture more than half of the small pharmacophore triplet diversity observed in non fragment-sized natural product datasets. Atom type analysis using radial fingerprints was represented by a self-organizing map. We examined the structural diversity of non-flat fragment-sized natural product scaffolds, rich in sp3 configured centres. From these results we demonstrate that 2-ring fragment-sized natural products effectively balance the opposing characteristics of minimal complexity and broad structural diversity when compared to the larger, more complex fragment-like natural products. These naturally-derived fragments could be used as the starting point for the generation of a highly diverse library with the scope for further medicinal chemistry elaboration due to their minimal structural complexity. This study highlights the possibility to capture a

  12. Capturing Nature's Diversity

    PubMed Central

    Pascolutti, Mauro; Campitelli, Marc; Nguyen, Bao; Pham, Ngoc; Gorse, Alain-Dominique; Quinn, Ronald J.

    2015-01-01

    Natural products are universally recognized to contribute valuable chemical diversity to the design of molecular screening libraries. The analysis undertaken in this work, provides a foundation for the generation of fragment screening libraries that capture the diverse range of molecular recognition building blocks embedded within natural products. Physicochemical properties were used to select fragment-sized natural products from a database of known natural products (Dictionary of Natural Products). PCA analysis was used to illustrate the positioning of the fragment subset within the property space of the non-fragment sized natural products in the dataset. Structural diversity was analysed by three distinct methods: atom function analysis, using pharmacophore fingerprints, atom type analysis, using radial fingerprints, and scaffold analysis. Small pharmacophore triplets, representing the range of chemical features present in natural products that are capable of engaging in molecular interactions with small, contiguous areas of protein binding surfaces, were analysed. We demonstrate that fragment-sized natural products capture more than half of the small pharmacophore triplet diversity observed in non fragment-sized natural product datasets. Atom type analysis using radial fingerprints was represented by a self-organizing map. We examined the structural diversity of non-flat fragment-sized natural product scaffolds, rich in sp3 configured centres. From these results we demonstrate that 2-ring fragment-sized natural products effectively balance the opposing characteristics of minimal complexity and broad structural diversity when compared to the larger, more complex fragment-like natural products. These naturally-derived fragments could be used as the starting point for the generation of a highly diverse library with the scope for further medicinal chemistry elaboration due to their minimal structural complexity. This study highlights the possibility to capture a

  13. Capturing the Daylight Dividend

    SciTech Connect

    Peter Boyce; Claudia Hunter; Owen Howlett

    2006-04-30

    Capturing the Daylight Dividend conducted activities to build market demand for daylight as a means of improving indoor environmental quality, overcoming technological barriers to effective daylighting, and informing and assisting state and regional market transformation and resource acquisition program implementation efforts. The program clarified the benefits of daylight by examining whole building systems energy interactions between windows, lighting, heating, and air conditioning in daylit buildings, and daylighting's effect on the human circadian system and productivity. The project undertook work to advance photosensors, dimming systems, and ballasts, and provided technical training in specifying and operating daylighting controls in buildings. Future daylighting work is recommended in metric development, technology development, testing, training, education, and outreach.

  14. Capturing Darwin's dream.

    PubMed

    Glenn, Travis C; Faircloth, Brant C

    2016-09-01

    Evolutionary biologists from Darwin forward have dreamed of having data that would elucidate our understanding of evolutionary history and the diversity of life. Sequence capture is a relatively old DNA technology, but its use is growing rapidly due to advances in (i) massively parallel DNA sequencing approaches and instruments, (ii) massively parallel bait construction, (iii) methods to identify target regions and (iv) sample preparation. We give a little historical context to these developments, summarize some of the important advances reported in this special issue and point to further advances that can be made to help fulfill Darwin's dream. PMID:27454358

  15. Sensitivity to Interaural Time Differences Conveyed in the Stimulus Envelope: Estimating Inputs of Binaural Neurons Through the Temporal Analysis of Spike Trains.

    PubMed

    Dietz, Mathias; Wang, Le; Greenberg, David; McAlpine, David

    2016-08-01

    Sound-source localization in the horizontal plane relies on detecting small differences in the timing and level of the sound at the two ears, including differences in the timing of the modulated envelopes of high-frequency sounds (envelope interaural time differences (ITDs)). We investigated responses of single neurons in the inferior colliculus (IC) to a wide range of envelope ITDs and stimulus envelope shapes. By a novel means of visualizing neural activity relative to different portions of the periodic stimulus envelope at each ear, we demonstrate the role of neuron-specific excitatory and inhibitory inputs in creating ITD sensitivity (or the lack of it) depending on the specific shape of the stimulus envelope. The underlying binaural brain circuitry and synaptic parameters were modeled individually for each neuron to account for neuron-specific activity patterns. The model explains the effects of envelope shapes on sensitivity to envelope ITDs observed in both normal-hearing listeners and in neural data, and has consequences for understanding how ITD information in stimulus envelopes might be maximized in users of bilateral cochlear implants-for whom ITDs conveyed in the stimulus envelope are the only ITD cues available. PMID:27294694

  16. Perceptual objects capture attention.

    PubMed

    Yeshurun, Yaffa; Kimchi, Ruth; Sha'shoua, Guy; Carmel, Tomer

    2009-06-01

    A recent study has demonstrated that the mere organization of some elements in the visual field into an object attracts attention automatically [Kimchi, R., Yeshurun, Y., & Cohen-Savransky, A. (2007). Automatic, stimulus-driven attentional capture by objecthood. Psychonomic Bulletin & Review, 14(1), 166-172]. We tested whether similar results will emerge when the target is not a part of the object and with simplified task demands. A matrix of 16 black L elements in various orientations preceded the presentation of a Vernier target. The target was either added to the matrix (Experiment 1), or appeared after its offset (Experiment 2). On some trials four elements formed a square-like object, and on some of these trials the target appeared in the center of the object. No featural uniqueness or abrupt onset was associated with the object and it did not predict the target location or the direction of the target's horizontal offset. Performance was better when the target appeared in the center of the object than in a different location than the object, even when the target appeared after the matrix offset. These findings support the hypothesis that a perceptual object captures attention (Kimchi et al., 2007), and demonstrate that this automatic deployment of attention to the object is robust and involves a spatial component. PMID:18299141

  17. Robust automated knowledge capture.

    SciTech Connect

    Stevens-Adams, Susan Marie; Abbott, Robert G.; Forsythe, James Chris; Trumbo, Michael Christopher Stefan; Haass, Michael Joseph; Hendrickson, Stacey M. Langfitt

    2011-10-01

    This report summarizes research conducted through the Sandia National Laboratories Robust Automated Knowledge Capture Laboratory Directed Research and Development project. The objective of this project was to advance scientific understanding of the influence of individual cognitive attributes on decision making. The project has developed a quantitative model known as RumRunner that has proven effective in predicting the propensity of an individual to shift strategies on the basis of task and experience related parameters. Three separate studies are described which have validated the basic RumRunner model. This work provides a basis for better understanding human decision making in high consequent national security applications, and in particular, the individual characteristics that underlie adaptive thinking.

  18. Capture-ejector satellites

    NASA Technical Reports Server (NTRS)

    Macconochie, I. O.; Eldred, C. H.; Martin, J. A.

    1983-01-01

    A satellite in the form of a large rotating rim which can be used to boost spacecraft from low-Earth orbit to higher orbits is described. The rim rotates in the plane of its orbit such that the lower portion of the rim is traveling at suborbital velocity, while the upper portion is travelling at greater than orbital velocity. Ascending spacecraft or payloads arrive at the lowest portion of the rim at suborbital velocities, where the payloads are released on a trajectory for higher orbits; descending payloads employ the reverse procedure. Electric thrusters placed on the rim maintain rim rotational speed and altitude. From the standpoint of currently known materials, the capture-ejector concept may be useful for relatively small velocity increments.

  19. Passive Ball Capture Joint

    NASA Technical Reports Server (NTRS)

    Cloyd, Richard A. (Inventor); Bryan, Thomas C. (Inventor)

    2003-01-01

    A passive ball capture joint has a sleeve with a plurality of bores distributed about a circumference thereof and formed therethrough at an acute angle relative to the sleeve's longitudinal axis. A spring-loaded retainer is slidingly fitted in each bore and is biased such that, if allowed, will extend at least partially into the sleeve to retain a ball therein. A ring, rotatably mounted about the bores, has an interior wall defining a plurality of shaped races that bear against the spring-loaded retainers. A mechanized rotational force producer is coupled to the ring. The ring can be rotated from a first position (that presses the retainers into the sleeve to lock the ball in place) to a second position (that allows the retainers to springback out of the sleeve to release the ball).

  20. Capturing the uncultivated majority

    SciTech Connect

    Green, Brian D.; Keller, Martin

    2007-04-02

    The metagenomic analysis of environmental microbialcommunities continues to be a rapidly developing area of study. DNAisolation, the first step in capturing the uncultivated majority, hasseen many advances in recent years. Protocols have been developed todistinguish DNA from live versus dead cells and to separate extracellularfrom intracellular DNA. Looking to increase our understanding of the rolethat members of a microbial community play in ecological processes,several techniques have been developed that are enabling greater indepthanalysis of environmental metagenomes. These include the development ofenvironmental gene tags and the serial analysis of 16S rRNA gene sequencetags. In addition, new screening methods have been designed to select forspecific functional genes within metagenomic libraries. Finally, newcultivation methods continue to be developed to improve our ability tocapture a greater diversity of microorganisms within theenvironment.

  1. Particle capture device

    DOEpatents

    Jayne, John T.; Worsnop, Douglas R.

    2016-02-23

    In example embodiments, particle collection efficiency in aerosol analyzers and other particle measuring instruments is improved by a particle capture device that employs multiple collisions to decrease momentum of particles until the particles are collected (e.g., vaporized or come to rest). The particle collection device includes an aperture through which a focused particle beam enters. A collection enclosure is coupled to the aperture and has one or more internal surfaces against which particles of the focused beam collide. One or more features are employed in the collection enclosure to promote particles to collide multiple times within the enclosure, and thereby be vaporized or come to rest, rather than escape through the aperture.

  2. Fragment capture device

    DOEpatents

    Payne, Lloyd R.; Cole, David L.

    2010-03-30

    A fragment capture device for use in explosive containment. The device comprises an assembly of at least two rows of bars positioned to eliminate line-of-sight trajectories between the generation point of fragments and a surrounding containment vessel or asset. The device comprises an array of at least two rows of bars, wherein each row is staggered with respect to the adjacent row, and wherein a lateral dimension of each bar and a relative position of each bar in combination provides blockage of a straight-line passage of a solid fragment through the adjacent rows of bars, wherein a generation point of the solid fragment is located within a cavity at least partially enclosed by the array of bars.

  3. Intact capture of hypervelocity projectiles.

    PubMed

    Tsou, P

    1990-01-01

    The ability to capture projectiles intact at hypervelocities opens new applications in science and technology that would either not be possible or would be very costly by other means. This capability has been demonstrated in the laboratory for aluminum projectiles of 1.6 mm diameter, captured at 6 km/s, in one unmelted piece, and retaining up to 95% of the original mass. Furthermore, capture was accomplished passively using microcellular underdense polymer foam. Another advantage of capturing projectiles in an underdense medium is the ability of such a medium to preserve a record of the projectile's original velocity components of speed and direction. A survey of these experimental results is described in terms of a dozen parameters which characterize the amount of capture and the effect on the projectile due to different capture media. PMID:11538362

  4. Lunar Sulfur Capture System

    NASA Technical Reports Server (NTRS)

    Berggren, Mark; Zubrin, Robert; Bostwick-White, Emily

    2013-01-01

    The Lunar Sulfur Capture System (LSCS) protects in situ resource utilization (ISRU) hardware from corrosion, and reduces contaminant levels in water condensed for electrolysis. The LSCS uses a lunar soil sorbent to trap over 98 percent of sulfur gases and about two-thirds of halide gases evolved during hydrogen reduction of lunar soils. LSCS soil sorbent is based on lunar minerals containing iron and calcium compounds that trap sulfur and halide gas contaminants in a fixed-bed reactor held at temperatures between 250 and 400 C, allowing moisture produced during reduction to pass through in vapor phase. Small amounts of Earth-based polishing sorbents consisting of zinc oxide and sodium aluminate are used to reduce contaminant concentrations to one ppm or less. The preferred LSCS configuration employs lunar soil beneficiation to boost concentrations of reactive sorbent minerals. Lunar soils contain sulfur in concentrations of about 0.1 percent, and halogen compounds including chlorine and fluorine in concentrations of about 0.01 percent. These contaminants are released as gases such as H2S, COS, CS2,HCl, and HF during thermal ISRU processing with hydrogen or other reducing gases. Removal of contaminant gases is required during ISRU processing to prevent hardware corrosion, electrolyzer damage, and catalyst poisoning. The use of Earth-supplied, single-use consumables to entirely remove contaminants at the levels existing in lunar soils would make many ISRU processes unattractive due to the large mass of consumables relative to the mass of oxygen produced. The LSCS concept of using a primary sorbent prepared from lunar soil was identified as a method by which the majority of contaminants could be removed from process gas streams, thereby substantially reducing the required mass of Earth-supplied consumables. The LSCS takes advantage of minerals containing iron and calcium compounds that are present in lunar soil to trap sulfur and halide gases in a fixedbed reactor

  5. The physics of intact capture

    NASA Technical Reports Server (NTRS)

    Tsou, Peter; Griffiths, D. J.; Albee, A. L.

    1994-01-01

    The ability to capture projectiles intact at hypervelocities in underdense media open a new area of study in physics. Underdense material behaves markedly different than solid, liquid, or gas upon hypervelocity impact. This new phenomenon enables applications in science that would either not be possible or would be very costly by other means. This phenomenon has been fully demonstrated in the laboratory and validated in space. Even more interesting is the fact that this hypervelocity intact capture was accomplished passively. A better understanding of the physics of intact capture will lead to improvements in intact capture. A collection of physical observations of this phenomenon is presented here.

  6. Resource capture by single leaves

    SciTech Connect

    Long, S.P.

    1992-05-01

    Leaves show a variety of strategies for maximizing CO{sub 2} and light capture. These are more meaningfully explained if they are considered in the context of maximizing capture relative to the utilization of water, nutrients and carbohydrates reserves. There is considerable variation between crops in their efficiency of CO{sub 2} and light capture at the leaf level. Understanding of these mechanisms indicate some ways in which efficiency of resource capture could be level cannot be meaningfully considered without simultaneous understanding of implications at the canopy level. 36 refs., 5 figs., 1 tab.

  7. Inland capture fisheries

    PubMed Central

    Welcomme, Robin L.; Cowx, Ian G.; Coates, David; Béné, Christophe; Funge-Smith, Simon; Halls, Ashley; Lorenzen, Kai

    2010-01-01

    The reported annual yield from inland capture fisheries in 2008 was over 10 million tonnes, although real catches are probably considerably higher than this. Inland fisheries are extremely complex, and in many cases poorly understood. The numerous water bodies and small rivers are inhabited by a wide range of species and several types of fisher community with diversified livelihood strategies for whom inland fisheries are extremely important. Many drivers affect the fisheries, including internal fisheries management practices. There are also many drivers from outside the fishery that influence the state and functioning of the environment as well as the social and economic framework within which the fishery is pursued. The drivers affecting the various types of inland water, rivers, lakes, reservoirs and wetlands may differ, particularly with regard to ecosystem function. Many of these depend on land-use practices and demand for water which conflict with the sustainability of the fishery. Climate change is also exacerbating many of these factors. The future of inland fisheries varies between continents. In Asia and Africa the resources are very intensely exploited and there is probably little room for expansion; it is here that resources are most at risk. Inland fisheries are less heavily exploited in South and Central America, and in the North and South temperate zones inland fisheries are mostly oriented to recreation rather than food production. PMID:20713391

  8. Captured by Aliens

    NASA Astrophysics Data System (ADS)

    Achenbach, Joel

    2000-03-01

    Captured by Aliens is a long and twisted voyage from science to the supernatural and back again. I hung out in Roswell, N.M., spent time with the Mars Society, met a guy who was figuring out the best way to build a spaceship to go to Alpha Centauri. I visited the set of the X-Files and talked to Mulder and Scully. One day over breakfast I was told by NASA administrator Dan Goldin, We live in a fog, man! He wants the big answers to the big questions. I spent a night in the base of a huge radio telescope in the boondocks of West Virginia, awaiting the signal from the aliens. I was hypnotized in a hotel room by someone who suspected that I'd been abducted by aliens and that this had triggered my interest in the topic. In the last months of his life, I talked to Carl Sagan, who believed that the galaxy riots with intelligent civilizations. He's my hero, for his steadfast adherence to the scientific method. What I found in all this is that the big question that needs immediate attention is not what's out THERE, but what's going on HERE, on Earth, and why we think the way we do, and how we came to be here in the first place.

  9. Capture-recapture methodology

    USGS Publications Warehouse

    Gould, William R.; Kendall, William L.

    2013-01-01

    Capture-recapture methods were initially developed to estimate human population abundance, but since that time have seen widespread use for fish and wildlife populations to estimate and model various parameters of population, metapopulation, and disease dynamics. Repeated sampling of marked animals provides information for estimating abundance and tracking the fate of individuals in the face of imperfect detection. Mark types have evolved from clipping or tagging to use of noninvasive methods such as photography of natural markings and DNA collection from feces. Survival estimation has been emphasized more recently as have transition probabilities between life history states and/or geographical locations, even where some states are unobservable or uncertain. Sophisticated software has been developed to handle highly parameterized models, including environmental and individual covariates, to conduct model selection, and to employ various estimation approaches such as maximum likelihood and Bayesian approaches. With these user-friendly tools, complex statistical models for studying population dynamics have been made available to ecologists. The future will include a continuing trend toward integrating data types, both for tagged and untagged individuals, to produce more precise and robust population models.

  10. Vehicle capture system

    NASA Astrophysics Data System (ADS)

    Tacke, Kenneth L.

    1998-12-01

    Primex Aerospace Company, under contract with the U.S. Army Armament Research Development & Engineering Center (ARDEC), has developed a portable vehicle capture system for use at vehicle checkpoints. Currently when a vehicle does not stop at a checkpoint, there are three possible reactions: let the vehicle go unchallenged, pursue the vehicle or stop the vehicle with lethal force. This system provides a non-lethal alternative that will stop and contain the vehicle. The system is completely portable with the heaviest component weighing less than 120 pounds. It can be installed with no external electrical power or permanent anchors required. In its standby mode, the system does not impede normal traffic, but on command erects a barrier in less than 1.5 seconds. System tests have been conducted using 5,100 and 8.400 pound vehicles, traveling at speeds up to 45 mph. The system is designed to minimize vehicle damage and occupant injury, typically resulting in deceleration forces of less than 2.5 gs on the vehicle. According to the drivers involved in tests at 45 mph, the stopping forces feel similar to a panic stop with the vehicle brakes locked. The system is completely reusable and be rapidly reset.

  11. Intact capture of cosmic dust

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1991-01-01

    The focus of this development effort is to capture dust particles at hypervelocities intact and unmelted in order to preserve volatile organics. At the same time, the capture process must minimize any organic elemental or compound contamination to prevent any compromise of exobiological analyses. Inorganic silicate aerogel has been developed as a successful capture medium to satisfy both requirements of intact capture and minimal organic contamination. Up to 6 km/s, silicate projectiles from a few microns up to 100 microns have been captured intact without any melting and with minimal loss of mass. Carbon in silicate aerogel can be reduced to less than 1 part in 1000 and hydrogen 3 parts in 1000 when baked in air. Under controlled inert gas environments, additional hydrocarbon reduction can be achieved.

  12. River Capture in Disequilibrium Landscapes

    NASA Astrophysics Data System (ADS)

    McCoy, S. W.; Perron, J.; Willett, S.; Goren, L.

    2013-12-01

    The process of river piracy or river capture has long drawn interest as a potential mechanism by which drainage basins large and small evolve towards an equilibrium state. River capture transfers both drainage area and drainage lines from one river basin to another, which can cause large, abrupt shifts in network topology, drainage divide positions, and river incision rates. Despite numerous case studies in which river capture has been proposed to have occurred, there is no general, mechanistic framework for understanding the controls on river capture, nor are there quantitative criteria for determining if capture has occurred. Here we use new metrics of landscape disequilibrium to first identify landscapes in which drainage reorganization is occurring. These metrics are based on a balance between an integral of the contributing drainage area and elevation. In an analysis of rivers in the Eastern United States we find that many rivers are in a state of disequilibrium and are experiencing recent or ongoing area exchange between basins. In these disequilibrium basins we find widespread evidence for network rearrangement via river capture at multiple scales. We then conduct numerical experiments with a 2-D landscape evolution model to explore the conditions in which area exchange among drainage basins is likely to occur as discrete capture events as opposed to continuous divide migration. These experiments indicate that: (1) capture activity increases with the degree of disequilibrium induced by persistent spatial gradients in tectonic forcing or by temporal changes in climate or tectonic forcing; (2) capture activity is strongly controlled by the initial planform drainage network geometry; and (3) capture activity scales with the fluvial incision rate constant in the river power erosion law.

  13. Iodine neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Ahmed, Kazi Fariduddin

    A new technique, Iodine Neutron Capture Therapy (INCT) is proposed to treat hyperthyroidism in people. Present thyroid therapies, surgical removal and 131I treatment, result in hypothyroidism and, for 131I, involve protracted treatment times and excessive whole-body radiation doses. The new technique involves using a low energy neutron beam to convert a fraction of the natural iodine stored in the thyroid to radioactive 128I, which has a 24-minute half-life and decays by emitting 2.12-MeV beta particles. The beta particles are absorbed in and damage some thyroid tissue cells and consequently reduce the production and release of thyroid hormones to the blood stream. Treatment times and whole-body radiation doses are thus reduced substantially. This dissertation addresses the first of the several steps needed to obtain medical profession acceptance and regulatory approval to implement this therapy. As with other such programs, initial feasibility is established by performing experiments on suitable small mammals. Laboratory rats were used and their thyroids were exposed to the beta particles coming from small encapsulated amounts of 128I. Masses of 89.0 mg reagent-grade elemental iodine crystals have been activated in the ISU AGN-201 reactor to provide 0.033 mBq of 128I. This activity delivers 0.2 Gy to the thyroid gland of 300-g male rats having fresh thyroid tissue masses of ˜20 mg. Larger iodine masses are used to provide greater doses. The activated iodine is encapsulated to form a thin (0.16 cm 2/mg) patch that is then applied directly to the surgically exposed thyroid of an anesthetized rat. Direct neutron irradiation of a rat's thyroid was not possible due to its small size. Direct in-vivo exposure of the thyroid of the rat to the emitted radiation from 128I is allowed to continue for 2.5 hours (6 half-lives). Pre- and post-exposure blood samples are taken to quantify thyroid hormone levels. The serum T4 concentration is measured by radioimmunoassay at

  14. Carbon Capture and Storage

    SciTech Connect

    Friedmann, S

    2007-10-03

    Carbon capture and sequestration (CCS) is the long-term isolation of carbon dioxide from the atmosphere through physical, chemical, biological, or engineered processes. This includes a range of approaches including soil carbon sequestration (e.g., through no-till farming), terrestrial biomass sequestration (e.g., through planting forests), direct ocean injection of CO{sub 2} either onto the deep seafloor or into the intermediate depths, injection into deep geological formations, or even direct conversion of CO{sub 2} to carbonate minerals. Some of these approaches are considered geoengineering (see the appropriate chapter herein). All are considered in the 2005 special report by the Intergovernmental Panel on Climate Change (IPCC 2005). Of the range of options available, geological carbon sequestration (GCS) appears to be the most actionable and economic option for major greenhouse gas reduction in the next 10-30 years. The basis for this interest includes several factors: (1) The potential capacities are large based on initial estimates. Formal estimates for global storage potential vary substantially, but are likely to be between 800 and 3300 Gt of C (3000 and 10,000 Gt of CO{sub 2}), with significant capacity located reasonably near large point sources of the CO{sub 2}. (2) GCS can begin operations with demonstrated technology. Carbon dioxide has been separated from large point sources for nearly 100 years, and has been injected underground for over 30 years (below). (3) Testing of GCS at intermediate scale is feasible. In the US, Canada, and many industrial countries, large CO{sub 2} sources like power plants and refineries lie near prospective storage sites. These plants could be retrofit today and injection begun (while bearing in mind scientific uncertainties and unknowns). Indeed, some have, and three projects described here provide a great deal of information on the operational needs and field implementation of CCS. Part of this interest comes from several

  15. Intact capture of hypervelocity particles

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    1986-01-01

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  16. Intact capture of hypervelocity particles

    NASA Astrophysics Data System (ADS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  17. Neutron capture reactions at DANCE

    SciTech Connect

    Bredeweg, T. A.

    2008-05-12

    The Detector for Advanced Neutron Capture Experiments (DANCE) is a 4{pi} BaF{sub 2} array consisting of 160 active detector elements. The primary purpose of the array is to perform neutron capture cross section measurements on small (> or approx.100 {mu}g) and/or radioactive (< or approx. 100 mCi) species. The measurements made possible with this array will be useful in answering outstanding questions in the areas of national security, threat reduction, nuclear astrophysics, advanced reactor design and accelerator transmutation of waste. Since the commissioning of DANCE we have performed neutron capture cross section measurements on a wide array of medium to heavy mass nuclides. Measurements to date include neutron capture cross sections on {sup 241,243}Am, neutron capture and neutron-induced fission cross sections and capture-to-fission ratio ({alpha} = {sigma}{sub {gamma}}/{sigma}{sub f}) for {sup 235}U using a new fission-tagging detector as well as neutron capture cross sections for several astrophysics branch-point nuclei. Results from several of these measurements will be presented along with a discussion of additional physics information that can be extracted from the DANCE data.

  18. Neutron capture reactions at DANCE

    NASA Astrophysics Data System (ADS)

    Bredeweg, T. A.

    2008-05-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) is a 4π BaF2 array consisting of 160 active detector elements. The primary purpose of the array is to perform neutron capture cross section measurements on small (>~100 μg) and/or radioactive (<~100 mCi) species. The measurements made possible with this array will be useful in answering outstanding questions in the areas of national security, threat reduction, nuclear astrophysics, advanced reactor design and accelerator transmutation of waste. Since the commissioning of DANCE we have performed neutron capture cross section measurements on a wide array of medium to heavy mass nuclides. Measurements to date include neutron capture cross sections on 241,243Am, neutron capture and neutron-induced fission cross sections and capture-to-fission ratio (α = σγ/σf) for 235U using a new fission-tagging detector as well as neutron capture cross sections for several astrophysics branch-point nuclei. Results from several of these measurements will be presented along with a discussion of additional physics information that can be extracted from the DANCE data.

  19. ISS Update: Capturing a Dragon

    NASA Video Gallery

    NASA Public Affairs Officer Josh Byerly talks with Melanie Miller, Robotics Officer, about the capture of the SpaceX Dragon commercial cargo craft by the Expedition 33 crew of the International Spa...

  20. Radiative capture reactions in astrophysics

    SciTech Connect

    Brune, Carl R.; Davids, Barry

    2015-08-07

    Here, the radiative capture reactions of greatest importance in nuclear astrophysics are identified and placed in their stellar contexts. Recent experimental efforts to estimate their thermally averaged rates are surveyed.

  1. ISS Update: Capturing a Dragon

    NASA Video Gallery

    NASA Public Affairs Officer Josh Byerly talks with space station training instructors Jeff Tuxhorn and Graeme Newman, who trained the space station crews on how to capture SpaceX’s Dragon spacecr...

  2. Toward transformational carbon capture systems

    SciTech Connect

    Miller, David C.; Litynski, John T.; Brickett, Lynn A.; Morreale, Bryan D.

    2015-10-28

    This paper will briefly review the history and current state of Carbon Capture and Storage (CCS) research and development and describe the technical barriers to carbon capture. it will argue forcefully for a new approach to R&D, which leverages both simulation and physical systems at the laboratory and pilot scales to more rapidly move the best technoogies forward, prune less advantageous approaches, and simultaneously develop materials and processes.

  3. Resonance capture at arbitrary inclination

    NASA Astrophysics Data System (ADS)

    Namouni, F.; Morais, M. H. M.

    2015-01-01

    Resonance capture is studied numerically in the three-body problem for arbitrary inclinations. Massless particles are set to drift from outside the 1:5 resonance with a Jupiter-mass planet thereby encountering the web of the planet's diverse mean motion resonances. Randomly constructed samples explore parameter space for inclinations from 0 to 180° with 5° increments totalling nearly 6 × 105 numerical simulations. 30 resonances internal and external to the planet's location are monitored. We find that retrograde resonances are unexpectedly more efficient at capture than prograde resonances and that resonance order is not necessarily a good indicator of capture efficiency at arbitrary inclination. Capture probability drops significantly at moderate sample eccentricity for initial inclinations in the range [10°,110°]. Orbit inversion is possible for initially circular orbits with inclinations in the range [60°,130°]. Capture in the 1:1 co-orbital resonance occurs with great likelihood at large retrograde inclinations. The planet's orbital eccentricity, if larger than 0.1, reduces the capture probabilities through the action of the eccentric Kozai-Lidov mechanism. A capture asymmetry appears between inner and outer resonances as prograde orbits are preferentially trapped in inner resonances. The relative capture efficiency of retrograde resonance suggests that the dynamical lifetimes of Damocloids and Centaurs on retrograde orbits must be significantly larger than those on prograde orbits implying that the recently identified asteroids in retrograde resonance, 2006 BZ8, 2008 SO218, 2009 QY6 and 1999 LE31 may be among the oldest small bodies that wander between the outer giant planets.

  4. Neutron densities from muon capture

    NASA Astrophysics Data System (ADS)

    Huan Ching, Chiang; Oset, Eulogio

    1991-10-01

    We show that, because of Pauli blocking and renormalization of the weak currents in nuclei, the muon capture rates are rather sensitive to the neutron distributions. We also show that, because of intrinsic theoretical uncertainties, neutron radia cannot be determined with precision but some reasonable limits can be given. However, the ratio of capture rates in different isotopes serves to determine the neutron radii of the isotopes provided the neutron density distribution for one of them is known.

  5. Capture of the gaze does not capture the mind.

    PubMed

    Lange, Elke B; Starzynski, Christian; Engbert, Ralf

    2012-08-01

    Sudden visual changes attract our gaze, and related eye movement control requires attentional resources. Attention is a limited resource that is also involved in working memory--for instance, memory encoding. As a consequence, theory suggests that gaze capture could impair the buildup of memory respresentations due to an attentional resource bottleneck. Here we developed an experimental design combining a serial memory task (verbal or spatial) and concurrent gaze capture by a distractor (of high or low similarity to the relevant item). The results cannot be explained by a general resource bottleneck. Specifically, we observed that capture by the low-similar distractor resulted in delayed and reduced saccade rates to relevant items in both memory tasks. However, while spatial memory performance decreased, verbal memory remained unaffected. In contrast, the high-similar distractor led to capture and memory loss for both tasks. Our results lend support to the view that gaze capture leads to activation of irrelevant representations in working memory that compete for selection at recall. Activation of irrelevant spatial representations distracts spatial recall, whereas activation of irrelevant verbal features impairs verbal memory performance. PMID:22648605

  6. Capturing carbon and saving coal

    SciTech Connect

    Johnson, J.

    2007-10-15

    Electric utilities face a tangle of choices when figuring how to pull CO{sub 2} from coal-fired plants. The article explains the three basic approaches to capturing CO{sub 2} - post-combustion, oxyfuel combustion and pre-combustion. Researchers at US DOE labs and utilities are investigating new solvents that capture CO{sub 2} more efficiently than amines and take less energy. Ammonium carbonate has been identified by EPRI as one suitable solvent. Field research projects on this are underway in the USA. Oxyfuel combustion trials are also being planned. Pre-combustion, or gasification is a completely different way of pulling energy from coal and, for electricity generation, this means IGCC systems. AEP, Southern Cinergy and Xcel are considering IGCC plants but none will capture CO{sub 2}. Rio Tinto and BP are planning a 500 MW facility to gasify coke waste from petroleum refining and collect and sequester CO{sub 2}. However, TECO recently dropped a project to build a 789 MW IGCC coal fired plant even though it was to receive a tax credit to encourage advanced coal technologies. The plant would not have captured CO{sub 2}. The company said that 'with uncertainty of carbon capture and sequestration regulations being discussed at the federal and state levels, the timing was not right'. 4 figs.

  7. CHAOTIC CAPTURE OF NEPTUNE TROJANS

    SciTech Connect

    Nesvorny, David; Vokrouhlicky, David

    2009-06-15

    Neptune Trojans (NTs) are swarms of outer solar system objects that lead/trail planet Neptune during its revolutions around the Sun. Observations indicate that NTs form a thick cloud of objects with a population perhaps {approx}10 times more numerous than that of Jupiter Trojans and orbital inclinations reaching {approx}25 deg. The high inclinations of NTs are indicative of capture instead of in situ formation. Here we study a model in which NTs were captured by Neptune during planetary migration when secondary resonances associated with the mean-motion commensurabilities between Uranus and Neptune swept over Neptune's Lagrangian points. This process, known as chaotic capture, is similar to that previously proposed to explain the origin of Jupiter's Trojans. We show that chaotic capture of planetesimals from an {approx}35 Earth-mass planetesimal disk can produce a population of NTs that is at least comparable in number to that inferred from current observations. The large orbital inclinations of NTs are a natural outcome of chaotic capture. To obtain the {approx}4:1 ratio between high- and low-inclination populations suggested by observations, planetary migration into a dynamically excited planetesimal disk may be required. The required stirring could have been induced by Pluto-sized and larger objects that have formed in the disk.

  8. Adaptive capture of expert behavior

    SciTech Connect

    Jones, R.D.; Barrett, C.L.; Hand, U.; Gordon, R.C.

    1994-08-01

    The authors smoothed and captured a set of expert rules with adaptive networks. The motivation for doing this is discussed. (1) Smoothing leads to stabler control actions. (2) For some sets of rules, the evaluation of the rules can be sped up. This is important in large-scale simulations where many intelligent elements are present. (3) Variability of the intelligent elements can be achieved by adjusting the weights in an adaptive network. (4) After capture has occurred, the weights can be adjusted based on performance criteria. The authors thus have the capability of learning a new set of rules that lead to better performance. The set of rules the authors chose to capture were based on a set of threat determining rules for tank commanders. The approach in this paper: (1) They smoothed the rules. The rule set was converted into a simple set of arithmetic statements. Continuous, non-binary inputs, are now permitted. (2) An operational measure of capturability was developed. (3) They chose four candidate networks for the rule set capture: (a) multi-linear network, (b) adaptive partial least squares, (c) connectionist normalized local spline (CNLS) network, and (d) CNLS net with a PLS preprocessor. These networks were able to capture the rule set to within a few percent. For the simple tank rule set, the multi-linear network performed the best. When the rules were modified to include more nonlinear behavior, CNLS net performed better than the other three nets which made linear assumptions. (4) The networks were tested for robustness to input noise. Noise levels of plus or minus 10% had no real effect on the network performance. Noise levels in the plus or minus 30% range degraded performance by a factor of two. Some performance enhancement occurred when the networks were trained with noisy data. (5) The scaling of the evaluation time was calculated. (6) Human variation can be mimicked in all the networks by perturbing the weights.

  9. Capturing Attention When Attention "Blinks"

    ERIC Educational Resources Information Center

    Wee, Serena; Chua, Fook K.

    2004-01-01

    Four experiments addressed the question of whether attention may be captured when the visual system is in the midst of an attentional blink (AB). Participants identified 2 target letters embedded among distractor letters in a rapid serial visual presentation sequence. In some trials, a square frame was inserted between the targets; as the only…

  10. EDOS Data Capture for ALOS

    NASA Technical Reports Server (NTRS)

    McLemore, Bruce; Cordier, Guy R.; Wood, Terri; Gamst, Harek

    2012-01-01

    In 2008, NASA's Earth Sciences Missions Operations (ESMO) at Goddard Space Flight Center (GSFC) directed the Earth Observing System Data Operations System (EDOS) project to provide a prototype system to assess the feasibility of high rate data capture for the Japan Aerospace Exploration Agency's (JAXA) Advanced Land Observing Satellite (ALOS) spacecraft via NASA's Tracking and Data Relay Satellite System (TDRSS). The key objective of this collaborative effort between NASA and JAXA was to share science data collected over North and South America previously unavailable due to limitations in ALOS downlink capacity. EDOS provided a single system proof-of-concept in 4 months at White Sands TDRS Ground Terminal The system captured 6 ALOS events error-free at 277 Mbps and delivered the data to the Alaska Satellite Facility (ASF) within 3 hours (May/June '08). This paper describes the successful rapid prototyping approach which led to a successful demonstration and agreement between NASA and JAXA for operational support. The design of the operational system will be discussed with emphasis on concurrent high-rate data capture, Level-O processing, real-time display and high-rate delivery with stringent latency requirements. A similar solution was successfully deployed at Svalbard, Norway to support the Suomi NPP launch (October 2011) and capture all X-band data and provide a 30-day backup archive.

  11. Orbital electron capture by the nucleus

    NASA Technical Reports Server (NTRS)

    Bambynek, W.; Behrens, H.; Chen, M. H.; Crasemann, B.; Fitzpatrick, M. L.; Ledingham, K. W. D.; Genz, H.; Mutterer, M.; Intemann, R. L.

    1976-01-01

    The theory of nuclear electron capture is reviewed in the light of current understanding of weak interactions. Experimental methods and results regarding capture probabilities, capture ratios, and EC/Beta(+) ratios are summarized. Radiative electron capture is discussed, including both theory and experiment. Atomic wave function overlap and electron exchange effects are covered, as are atomic transitions that accompany nuclear electron capture. Tables are provided to assist the reader in determining quantities of interest for specific cases.

  12. Natural materials for carbon capture.

    SciTech Connect

    Myshakin, Evgeniy M.; Romanov, Vyacheslav N.; Cygan, Randall Timothy

    2010-11-01

    Naturally occurring clay minerals provide a distinctive material for carbon capture and carbon dioxide sequestration. Swelling clay minerals, such as the smectite variety, possess an aluminosilicate structure that is controlled by low-charge layers that readily expand to accommodate water molecules and, potentially, carbon dioxide. Recent experimental studies have demonstrated the efficacy of intercalating carbon dioxide in the interlayer of layered clays but little is known about the molecular mechanisms of the process and the extent of carbon capture as a function of clay charge and structure. A series of molecular dynamics simulations and vibrational analyses have been completed to assess the molecular interactions associated with incorporation of CO2 in the interlayer of montmorillonite clay and to help validate the models with experimental observation.

  13. Spacecraft capture and docking system

    NASA Technical Reports Server (NTRS)

    Kong, Kinyuen (Inventor); Rafeek, Shaheed (Inventor); Myrick, Thomas (Inventor)

    2001-01-01

    A system for capturing and docking an active craft to a passive craft has a first docking assembly on the active craft with a first contact member and a spike projecting outwardly, a second docking assembly on the passive craft having a second contact member and a flexible net deployed over a target area with an open mesh for capturing the end of the spike of the active craft, and a motorized net drive for reeling in the net and active craft to mate with the passive craft's docking assembly. The spike has extendable tabs to allow it to become engaged with the net. The net's center is coupled to a net spool for reeling in. An alignment funnel has inclined walls to guide the net and captured spike towards the net spool. The passive craft's docking assembly includes circumferentially spaced preload wedges which are driven to lock the wedges against the contact member of the active craft. The active craft's docking assembly includes a rotary table and drive for rotating it to a predetermined angular alignment position, and mating connectors are then engaged with each other. The system may be used for docking spacecraft in zero or low-gravity environments, as well as for docking underwater vehicles, docking of ancillary craft to a mother craft in subsonic flight, in-flight refueling systems, etc.

  14. Realistic costs of carbon capture

    SciTech Connect

    Al Juaied, Mohammed . Belfer Center for Science and International Affiaris); Whitmore, Adam )

    2009-07-01

    There is a growing interest in carbon capture and storage (CCS) as a means of reducing carbon dioxide (CO2) emissions. However there are substantial uncertainties about the costs of CCS. Costs for pre-combustion capture with compression (i.e. excluding costs of transport and storage and any revenue from EOR associated with storage) are examined in this discussion paper for First-of-a-Kind (FOAK) plant and for more mature technologies, or Nth-of-a-Kind plant (NOAK). For FOAK plant using solid fuels the levelised cost of electricity on a 2008 basis is approximately 10 cents/kWh higher with capture than for conventional plants (with a range of 8-12 cents/kWh). Costs of abatement are found typically to be approximately US$150/tCO2 avoided (with a range of US$120-180/tCO2 avoided). For NOAK plants the additional cost of electricity with capture is approximately 2-5 cents/kWh, with costs of the range of US$35-70/tCO2 avoided. Costs of abatement with carbon capture for other fuels and technologies are also estimated for NOAK plants. The costs of abatement are calculated with reference to conventional SCPC plant for both emissions and costs of electricity. Estimates for both FOAK and NOAK are mainly based on cost data from 2008, which was at the end of a period of sustained escalation in the costs of power generation plant and other large capital projects. There are now indications of costs falling from these levels. This may reduce the costs of abatement and costs presented here may be 'peak of the market' estimates. If general cost levels return, for example, to those prevailing in 2005 to 2006 (by which time significant cost escalation had already occurred from previous levels), then costs of capture and compression for FOAK plants are expected to be US$110/tCO2 avoided (with a range of US$90-135/tCO2 avoided). For NOAK plants costs are expected to be US$25-50/tCO2. Based on these considerations a likely representative range of costs of abatement from CCS excluding

  15. Target capture and target ghosts

    NASA Astrophysics Data System (ADS)

    Auerbach, Steven P.

    1996-05-01

    Optimal detection methods for small targets rely on whitened matched filters, which convolve the measured data with the signal model, and whiten the result with the noise covariance. In real-world implementations of such filters, the noise covariance must be estimated from the data, and the resulting covariance estimate may be corrupted by presence of the target. The resulting loss in SNR is called 'target capture'. Target capture is often thought to be a problem only for bright targets. This presentation shows that target capture also arises for dim targets, leading to an SNR loss which is independent of target strength and depends on the averaging method used to estimate the noise covariance. This loss is due to a 'coherent beat' between the true noise and that portion of the estimated noise covariance due to the target. This beat leads to 'ghost targets', which diminish the target SNR by producing a negative target ghost at the target's position. A quantitative estimate of this effect will be given, and shown to agree with numerical results. The effect of averaging on SNR is also discussed for data scenes with synthetic injected targets, in cases where the noise covariance is estimated using 'no target' data. For these cases, it is shown that the so-called 'optimal' filter, which uses the true noise covariance, is actually worse than a 'sub-optimal' filter which estimates the noise from scene. This apparent contradiction is resolved by showing that the optimal filter is best if the same filter is used for many scenes, but is outperformed by a filter adapted to a specific scene.

  16. Algal Energy Conversion and Capture

    NASA Astrophysics Data System (ADS)

    Hazendonk, P.

    2015-12-01

    We address the potential for energy conversions and capture for: energy generation; reduction in energy use; reduction in greenhouse gas emissions; remediation of water and air pollution; protection and enhancement of soil fertility. These processes have the potential to sequester carbon at scales that may have global impact. Energy conversion and capture strategies evaluate energy use and production from agriculture, urban areas and industries, and apply existing and emerging technologies to reduce and recapture energy embedded in waste products. The basis of biocrude production from Micro-algal feedstocks: 1) The nutrients from the liquid fraction of waste streams are concentrated and fed into photo bioreactors (essentially large vessels in which microalgae are grown) along with CO2 from flue gasses from down stream processes. 2) The algae are processed to remove high value products such as proteins and beta-carotenes. The advantage of algae feedstocks is the high biomass productivity is 30-50 times that of land based crops and the remaining biomass contains minimal components that are difficult to convert to biocrude. 3) The remaining biomass undergoes hydrothermal liquefaction to produces biocrude and biochar. The flue gasses of this process can be used to produce electricity (fuel cell) and subsequently fed back into the photobioreactor. The thermal energy required for this process is small, hence readily obtained from solar-thermal sources, and furthermore no drying or preprocessing is required keeping the energy overhead extremely small. 4) The biocrude can be upgraded and refined as conventional crude oil, creating a range of liquid fuels. In principle this process can be applied on the farm scale to the municipal scale. Overall, our primary food production is too dependent on fossil fuels. Energy conversion and capture can make food production sustainable.

  17. Enhanced image capture through fusion

    NASA Technical Reports Server (NTRS)

    Burt, Peter J.; Hanna, Keith; Kolczynski, Raymond J.

    1993-01-01

    Image fusion may be used to combine images from different sensors, such as IR and visible cameras, to obtain a single composite with extended information content. Fusion may also be used to combine multiple images from a given sensor to form a composite image in which information of interest is enhanced. We present a general method for performing image fusion and show that this method is effective for diverse fusion applications. We suggest that fusion may provide a powerful tool for enhanced image capture with broad utility in image processing and computer vision.

  18. Carbon Capture and Storage, 2008

    ScienceCinema

    None

    2010-01-08

    The U.S. Department of Energy is researching the safe implementation of a technology called carbon sequestration, also known as carbon capture and storage, or CCS. Based on an oilfield practice, this approach stores carbon dioxide, or CO2 generated from human activities for millennia as a means to mitigate global climate change. In 2003, the Department of Energys National Energy Technology Laboratory formed seven Regional Carbon Sequestration Partnerships to assess geologic formations suitable for storage and to determine the best approaches to implement carbon sequestration in each region. This video describes the work of these partnerships.

  19. Carbon Capture and Storage, 2008

    SciTech Connect

    2009-03-19

    The U.S. Department of Energy is researching the safe implementation of a technology called carbon sequestration, also known as carbon capture and storage, or CCS. Based on an oilfield practice, this approach stores carbon dioxide, or CO2 generated from human activities for millennia as a means to mitigate global climate change. In 2003, the Department of Energys National Energy Technology Laboratory formed seven Regional Carbon Sequestration Partnerships to assess geologic formations suitable for storage and to determine the best approaches to implement carbon sequestration in each region. This video describes the work of these partnerships.

  20. 49 CFR 563.9 - Data capture.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Data capture. 563.9 Section 563.9 Transportation..., DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.9 Data capture. The EDR must capture and record the data elements for events in accordance with the following conditions and circumstances: (a) In...

  1. 49 CFR 563.9 - Data capture.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Data capture. 563.9 Section 563.9 Transportation..., DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.9 Data capture. Link to an amendment published at 76 FR 47489, Aug. 5, 2011. The EDR must capture and record the data elements for events in...

  2. 49 CFR 563.9 - Data capture.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 6 2012-10-01 2012-10-01 false Data capture. 563.9 Section 563.9 Transportation..., DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.9 Data capture. The EDR must capture and record the data elements for events in accordance with the following conditions and circumstances: (a) In...

  3. 49 CFR 563.9 - Data capture.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 6 2013-10-01 2013-10-01 false Data capture. 563.9 Section 563.9 Transportation..., DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.9 Data capture. The EDR must capture and record the data elements for events in accordance with the following conditions and circumstances: (a) In...

  4. 49 CFR 563.9 - Data capture.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 6 2014-10-01 2014-10-01 false Data capture. 563.9 Section 563.9 Transportation..., DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.9 Data capture. The EDR must capture and record the data elements for events in accordance with the following conditions and circumstances: (a) In...

  5. The Effectiveness of Classroom Capture Technology

    ERIC Educational Resources Information Center

    Ford, Maire B.; Burns, Colleen E.; Mitch, Nathan; Gomez, Melissa M.

    2012-01-01

    The use of classroom capture systems (systems that capture audio and video footage of a lecture and attempt to replicate a classroom experience) is becoming increasingly popular at the university level. However, research on the effectiveness of classroom capture systems in the university classroom has been limited due to the recent development and…

  6. Adaptive capture of expert knowledge

    SciTech Connect

    Barrett, C.L.; Jones, R.D.; Hand, Un Kyong |

    1995-05-01

    A method is introduced that can directly acquire knowledge-engineered, rule-based logic in an adaptive network. This adaptive representation of the rule system can then replace the rule system in simulated intelligent agents and thereby permit further performance-based adaptation of the rule system. The approach described provides both weight-fitting network adaptation and potentially powerful rule mutation and selection mechanisms. Nonlinear terms are generated implicitly in the mutation process through the emergent interaction of multiple linear terms. By this method it is possible to acquire nonlinear relations that exist in the training data without addition of hidden layers or imposition of explicit nonlinear terms in the network. We smoothed and captured a set of expert rules with an adaptive network. The motivation for this was to (1) realize a speed advantage over traditional rule-based simulations; (2) have variability in the intelligent objects not possible by rule-based systems but provided by adaptive systems: and (3) maintain the understandability of rule-based simulations. A set of binary rules was smoothed and converted into a simple set of arithmetic statements, where continuous, non-binary rules are permitted. A neural network, called the expert network, was developed to capture this rule set, which it was able to do with zero error. The expert network is also capable of learning a nonmonotonic term without a hidden layer. The trained network in feedforward operation is fast running, compact, and traceable to the rule base.

  7. The elements of design knowledge capture

    NASA Technical Reports Server (NTRS)

    Freeman, Michael S.

    1988-01-01

    This paper will present the basic constituents of a design knowledge capture effort. This will include a discussion of the types of knowledge to be captured in such an effort and the difference between design knowledge capture and more traditional knowledge base construction. These differences include both knowledge base structure and knowledge acquisition approach. The motivation for establishing a design knowledge capture effort as an integral part of major NASA programs will be outlined, along with the current NASA position on that subject. Finally the approach taken in design knowledge capture for Space Station will be contrasted with that used in the HSTDEK project.

  8. Neutron capture cross section of 136 Xe

    NASA Astrophysics Data System (ADS)

    Daugherty, Sean; Albert, Joshua; Johnson, Tessa; O'Conner, Thomasina; Kaufman, Lisa

    2015-04-01

    136 Xe is an important 0 νββ candidate, studied in experiments such as EXO-200 and, in the future, nEXO. These experiments require a precise study of neutron capture for their background models. The neutron capture cross section of 136 Xe has been measured at the Detector for Advanced Capture Experiments (DANCE) at the Los Alamos Neutron Science Center. A neutron beam ranging from thermal energy to 100 keV was incident on a gas cell filled with isotopically pure 136 Xe . We will discuss the measurement of partial neutron capture cross sections at thermal and first neutron resonance energies along with corresponding capture gamma cascades.

  9. Earth-Mars transfers with ballistic capture

    NASA Astrophysics Data System (ADS)

    Topputo, F.; Belbruno, E.

    2015-04-01

    We construct a new type of transfer from the Earth to Mars, which ends in ballistic capture. This results in substantial savings in capture from that of a classical Hohmann transfer under certain assumptions as well as an alternate way for spacecraft to transfer to Mars. This is accomplished by first becoming captured at Mars, very distant from the planet, and then from there, following a ballistic capture transfer to a desired altitude within a ballistic capture set. This is achieved by using stable sets, which are sets of initial conditions whose orbits satisfy a definition of orbital stability. This transfer type may be of interest for Mars missions because of low capture , flexibility of launch period from the Earth, moderate flight time, and the benign nature of the capture process.

  10. Capture of uncontrolled satellites - A flight demonstration

    NASA Technical Reports Server (NTRS)

    Lenox, H. M.

    1984-01-01

    NASA is presently exploring concepts, systems, and devices for capturing uncontrolled or non-operational satellites. Understanding of this type capture involves development of requirements and options, analyses of approaches, and extensive ground simulations. The verification of an approach is expected to require flight demonstrations of the concepts and hardware to assure confidence in application. This paper addresses a flight demonstration involving the Shuttle, an Orbital Maneuvering Vehicle (OMV), a capture mechanism, and a target vehicle capable of providing characteristic motion. A mission scenario is projected which demonstrates a capture concept, mission sequencing, capture vehicle potential, and overall capture possibilities with man-in-the-loop control. The proposed demonstration is considered a stepping stone to more demanding capture requirements. On-orbit activities are deliberately constrained to existing technology and projected systems and hardware capability for the year 1990.

  11. Small Particles Intact Capture Experiment (SPICE)

    NASA Astrophysics Data System (ADS)

    Nishioka, Ken-Ji; Carle, G. C.; Bunch, T. E.; Mendez, David J.; Ryder, J. T.

    The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

  12. Small Particles Intact Capture Experiment (SPICE)

    NASA Technical Reports Server (NTRS)

    Nishioka, Ken-Ji; Carle, G. C.; Bunch, T. E.; Mendez, David J.; Ryder, J. T.

    1994-01-01

    The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

  13. Bad data packet capture device

    DOEpatents

    Chen, Dong; Gara, Alan; Heidelberger, Philip; Vranas, Pavlos

    2010-04-20

    An apparatus and method for capturing data packets for analysis on a network computing system includes a sending node and a receiving node connected by a bi-directional communication link. The sending node sends a data transmission to the receiving node on the bi-directional communication link, and the receiving node receives the data transmission and verifies the data transmission to determine valid data and invalid data and verify retransmissions of invalid data as corresponding valid data. A memory device communicates with the receiving node for storing the invalid data and the corresponding valid data. A computing node communicates with the memory device and receives and performs an analysis of the invalid data and the corresponding valid data received from the memory device.

  14. Subsurface capture of carbon dioxide

    SciTech Connect

    Blount, Gerald; Siddal, Alvin A.; Falta, Ronald W.

    2014-07-22

    A process and apparatus of separating CO.sub.2 gas from industrial off-gas source in which the CO.sub.2 containing off-gas is introduced deep within an injection well. The CO.sub.2 gases are dissolved in the, liquid within the injection well while non-CO.sub.2 gases, typically being insoluble in water or brine, are returned to the surface. Once the CO.sub.2 saturated liquid is present within the injection well, the injection well may be used for long-term geologic storage of CO.sub.2 or the CO.sub.2 saturated liquid can be returned to the surface for capturing a purified CO.sub.2 gas.

  15. Boron-neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Haque, A. M.; Moschini, G.; Valkovic, Vlado; Zafiropoulos, D.

    1995-03-01

    The final goal of any radiotherapy project is to expose the tumor as the target to a lethal dose of ionizing radiation, sparing thereby the surrounding healthy tissues to a maximum extent. Precise treatment is nevertheless essential for cure, since the danger exists that the tumor might re-establish itself if every cancer cell is not destroyed. The conventional therapy treatments existing to date, e.g., surgery, radiation therapy, and chemotherapy, have been successful in curing some kinds of cancers, but still there are many exceptions. In the following, the progress of a promising therapy tool, called the boron neutron capture therapy (BNCT), which has made its dynamic evolution in recent years, is briefly described. The approach towards clinical trials with BNCT is described in detail.

  16. Brownian motion using video capture

    NASA Astrophysics Data System (ADS)

    Salmon, Reese; Robbins, Candace; Forinash, Kyle

    2002-05-01

    Although other researchers had previously observed the random motion of pollen grains suspended in water through a microscope, Robert Brown's name is associated with this behaviour based on observations he made in 1828. It was not until Einstein's work in the early 1900s however, that the origin of this irregular motion was established to be the result of collisions with molecules which were so small as to be invisible in a light microscope (Einstein A 1965 Investigations on the Theory of the Brownian Movement ed R Furth (New York: Dover) (transl. Cowper A D) (5 papers)). Jean Perrin in 1908 (Perrin J 1923 Atoms (New York: Van Nostrand-Reinhold) (transl. Hammick D)) was able, through a series of painstaking experiments, to establish the validity of Einstein's equation. We describe here the details of a junior level undergraduate physics laboratory experiment where students used a microscope, a video camera and video capture software to verify Einstein's famous calculation of 1905.

  17. Neutron capture therapy for melanoma

    SciTech Connect

    Coderre, J.A.; Glass, J.D.; Micca, P.; Fairchild, R.G.

    1988-01-01

    The development of boron-containing compounds which localize selectively in tumor may require a tumor-by-tumor type of approach that exploits any metabolic pathways unique to the particular type of tumor. Melanin-producing melanomas actively transport and metabolize aromatic amino acids for use as precursors in the synthesis of the pigment melanin. It has been shown that the boron-containing amino acid analog p-borono-phenylalanine (BPA) is selectively accumulated in melanoma tissue, producing boron concentrations in tumor that are within the range estimated to be necessary for successful boron neutron capture therapy (BNCT). We report here the results of therapy experiments carried out at the Brookhaven Medical Research Reactor (BMRR). 21 refs., 5 figs., 3 tabs.

  18. Workshop on neutron capture therapy

    SciTech Connect

    Fairchild, R.G.; Bond, V.P.

    1986-01-01

    Potentially optimal conditions for Neutron Capture Therapy (NCT) may soon be in hand due to the anticipated development of band-pass filtered beams relatively free of fast neutron contaminations, and of broadly applicable biomolecules for boron transport such as porphyrins and monoclonal antibodies. Consequently, a number of groups in the US are now devoting their efforts to exploring NCT for clinical application. The purpose of this Workshop was to bring these groups together to exchange views on significant problems of mutual interest, and to assure a unified and effective approach to the solutions. Several areas of preclinical investigation were deemed to be necessary before it would be possible to initiate clinical studies. As neither the monomer nor the dimer of sulfhydryl boron hydride is unequivocally preferable at this time, studies on both compounds should be continued until one is proven superior.

  19. Direct-Semidirect Thermal Neutron Capture Calculations

    SciTech Connect

    Arbanas, G; Dietrich, F S; Kerman, A K

    2005-12-20

    A method for computing direct-semidirect (DSD) neutron radiative capture is presented and applied to thermal neutron capture on {sup 19}F, {sup 27}Al, {sup 28,29.30}Si, {sup 35,37}Cl, {sup 39,41}K, {sup 56}Fe, and {sup 238}U, in support of data evaluation effort at the O.R.N.L. The DSD method includes both direct and semidirect capture; the latter is a core-polarization term in which the giant dipole resonance is formed. We study the effects of a commonly used ''density'' approximation to the EM operator and find it to be unsatisfactory for the nuclei considered here. We also study the magnitude of semidirect capture relative to the pure direct capture. Furthermore, we compare our results with those obtained from another direct capture code (Tedca [17]). We also compare our results with those obtained from analytical expression for external capture derived by Lane and Lynn [3], and its extension to include internal capture [7]. To estimate the effect of nuclear deformation on direct capture, we computed direct thermal capture on {sup 238}U with and without imposition of spherical symmetry. Direct capture for a spherically symmetric {sup 238}U was approximately 6 mb, while a quadrupole deformation of 0.215 on the shape of {sup 238}U lowers this cross section down to approximately 2 mb. This result suggests that effects of nuclear deformation on direct capture warrant a further study. We also find out that contribution to the direct capture on {sup 238}U from the nuclear interior significantly cancels that coming from the exterior region, and hence both contributions must be taken into account. We reproduced a well known discrepancy between the computed and observed branching ratios in {sup 56}Fe(n,{gamma}). This will lead us to revisit the concept of doorway states in the particle-hole model.

  20. Accelerators and Neutron Capture Therapy

    NASA Astrophysics Data System (ADS)

    Burlon, A. A.; Kreiner, A. J.; Valda, A.

    2002-08-01

    Within the frame of Accelerator Based Boron Neutron Capture Therapy (AB-BNCT), the 7Li (p,n) 7Be reaction, relatively near its energy threshold is one of the most promising, due to its high yield and low neutron energy. In this work a thick LiF target irradiated with a proton beam was studied as a neutron source. The 1.88-2.0 MeV proton beam was produced by the tandem accelerator TANDAR at CNEA's facilities in Buenos Aires. A water-filled phantom, containing a boron sample was irradiated with the resulting neutron flux. The 10B(n,αγ)7Li boron neutron capture reaction produces a 0.478 MeV gamma ray in 94% of the cases. The neutron yield was measured through the detection of this gamma ray using a hyperpure germanium detector with an anti-Compton shield. In addition, the thermal neutron flux was evaluated at different depths inside the phantom using bare and Cd-covered gold foils. A maximum neutron thermal flux of 1.4×108 cm-2s-1mA-1 was obtained at 4.2 cm from the phantom surface. In order to optimize the design of the neutron production target and the beam shaping assembly extensive Monte Carlo Neutron and Photon (MCNP) simulations have been performed. Neutron fields from a thick LiF and a Li metal target (with both a D2O-graphite and a Al/AlF3-graphite moderator/reflector assembly) were evaluated along the centerline of a head and a whole body phantom. Simulations were carried out for 1.89, 2.0 and 2.3 MeV proton beams. The results show that it is more advantageous to irradiate the target with 2.3 MeV near-resonance protons, instead of very near threshold, because of the higher neutron yield at this energy. On the other hand, the Al/AlF3-graphite exhibits a more efficient performance than D2O in terms of tumor to maximum healthy tissue dose ratio. Treatment times of less than 15 min and tumor control probabilities larger than 98% are obtained for a 50 mA, 2.3 MeV proton beam. The alternative neutron-producing reaction 13C(d,n) is also briefly reviewed. A

  1. Silica Aerogel Captures Cosmic Dust Intact

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1994-01-01

    The mesostructure of silica aerogel resembles stings of grapes, ranging in size from 10 to 100 angstrom. This fine mesostructure transmits nearly 90 percent of incident light in the visible, while providing sufficiently gentle dissipation of the kinetric energy of hypervelocity cosmic dust particles to permit their intact capture. We introduced silica aerogel in 1987 as capture medium to take advantage of its low density, fine mesostruicture and most importantly, its transparency, allowing optical location of captured micron sized particles.

  2. Techniques for capturing bighorn sheep lambs

    USGS Publications Warehouse

    Smith, Joshua B.; Walsh, Daniel P.; Goldstein, Elise J.; Parsons, Zachary D.; Karsch, Rebekah C.; Stiver, Julie R.; Cain, James W.; Raedeke, Kenneth J.; Jenks, Jonathan A.

    2014-01-01

    Low lamb recruitment is a major challenge facing managers attempting to mitigate the decline of bighorn sheep (Ovis canadensis), and investigations into the underlying mechanisms are limited because of the inability to readily capture and monitor bighorn sheep lambs. We evaluated 4 capture techniques for bighorn sheep lambs: 1) hand-capture of lambs from radiocollared adult females fitted with vaginal implant transmitters (VITs), 2) hand-capture of lambs of intensively monitored radiocollared adult females, 3) helicopter net-gunning, and 4) hand-capture of lambs from helicopters. During 2010–2012, we successfully captured 90% of lambs from females that retained VITs to ≤1 day of parturition, although we noted differences in capture rates between an area of high road density in the Black Hills (92–100%) of South Dakota, USA, and less accessible areas of New Mexico (71%), USA. Retention of VITs was 78% with pre-partum expulsion the main cause of failure. We were less likely to capture lambs from females that expelled VITs ≥1 day of parturition (range = 80–83%) or females that were collared without VITs (range = 60–78%). We used helicopter net-gunning at several sites in 1999, 2001–2002, and 2011, and it proved a useful technique; however, at one site, attempts to capture lambs led to lamb predation by golden eagles (Aquila chrysaetos). We attempted helicopter hand-captures at one site in 1999, and they also were successful in certain circumstances and avoided risk of physical trauma from net-gunning; however, application was limited. In areas of low accessibility or if personnel lack the ability to monitor females and/or VITs for extended periods, helicopter capture may provide a viable option for lamb capture.

  3. TARGETED CAPTURE IN EVOLUTIONARY AND ECOLOGICAL GENOMICS

    PubMed Central

    Jones, Matthew R.; Good, Jeffrey M.

    2016-01-01

    The rapid expansion of next-generation sequencing has yielded a powerful array of tools to address fundamental biological questions at a scale that was inconceivable just a few years ago. Various genome partitioning strategies to sequence select subsets of the genome have emerged as powerful alternatives to whole genome sequencing in ecological and evolutionary genomic studies. High throughput targeted capture is one such strategy that involves the parallel enrichment of pre-selected genomic regions of interest. The growing use of targeted capture demonstrates its potential power to address a range of research questions, yet these approaches have yet to expand broadly across labs focused on evolutionary and ecological genomics. In part, the use of targeted capture has been hindered by the logistics of capture design and implementation in species without established reference genomes. Here we aim to 1) increase the accessibility of targeted capture to researchers working in non-model taxa by discussing capture methods that circumvent the need of a reference genome, 2) highlight the evolutionary and ecological applications where this approach is emerging as a powerful sequencing strategy, and 3) discuss the future of targeted capture and other genome partitioning approaches in light of the increasing accessibility of whole genome sequencing. Given the practical advantages and increasing feasibility of high-throughput targeted capture, we anticipate an ongoing expansion of capture-based approaches in evolutionary and ecological research, synergistic with an expansion of whole genome sequencing. PMID:26137993

  4. Opportunity Captures 'Lion King' Panorama

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] Click on the image for Opportunity Captures 'Lion King' Panorama (QTVR)

    This approximate true-color panorama, dubbed 'Lion King,' shows 'Eagle Crater' and the surrounding plains of Meridiani Planum. It was obtained by the Mars Exploration Rover Opportunity's panoramic camera on sols 58 and 60 using infrared (750-nanometer), green (530-nanometer) and blue (430-nanometer) filters.

    This is the largest panorama obtained yet by either rover. It was taken in eight segments using six filters per segment, for a total of 558 images and more than 75 megabytes of data. Additional lower elevation tiers were added to ensure that the entire crater was covered in the mosaic.

    This panorama depicts a story of exploration including the rover's lander, a thorough examination of the outcrop, a study of the soils at the near-side of the lander, a successful exit from Eagle Crater and finally the rover's next desination, the large crater dubbed 'Endurance'.

  5. Light capture by human cones.

    PubMed Central

    Chen, B; Makous, W

    1989-01-01

    1. The variation in visual efficiency of light with varying pupillary entry (the Stiles-Crawford effect) was measured to determine the proportion of light incident on the cones that escapes them without recovery by other cones. 2. The variation in detectability of interference fringes with varying pupillary entry of the interfering beams was measured to determine the proportion of incident light that was recaptured by cones in the dark stripes after escaping cones in the bright stripes of the fringes. 3. By exclusion, these observations determine the variation, with varying pupillary entry, in the proportion of incident light that was captured and absorbed by the first cones it entered. 4. Some 70-90% of the light absorbed by the cones when it passes through the centre of the pupil, is entirely lost to the visual system if it passes instead through the margin of the (dilated) pupil. 5. Over half the light that cones absorb when the light enters the margin of the pupil is light that has previously passed through other cones. 6. If the spread of recaptured light is assumed to be Gaussian, its standard deviation is at most one minute of visual angle. 7. Such recaptured light makes a previously unknown contribution to the various Stiles-Crawford effects. PMID:2607444

  6. Perceptions of Presentation Capture in Counselor Education

    ERIC Educational Resources Information Center

    Gibson, Robert; Miller, Ann

    2011-01-01

    Lecture/presentation capture is a gradually emerging technology at many colleges and universities and will likely increase in use because students prefer courses that offer online lectures over traditional classes that do not. Many capture products also allow faculty to segment and edit lectures, add/exchange notations, view lectures on mobile…

  7. Phase Errors and the Capture Effect

    SciTech Connect

    Blair, J., and Machorro, E.

    2011-11-01

    This slide-show presents analysis of spectrograms and the phase error of filtered noise in a signal. When the filtered noise is smaller than the signal amplitude, the phase error can never exceed 90{deg}, so the average phase error over many cycles is zero: this is called the capture effect because the largest signal captures the phase and frequency determination.

  8. The Bells' Capture note TH-3054-CERN

    SciTech Connect

    Hartouni, Ed P.

    2014-01-29

    This document revisits the paper by M. Bell and J. S. Bell “Capture of Cooling Electrons by Cool Protons” TH-3054-CERN (March 30, 1981). I expand the treatment to include e+e- capture.

  9. Neutron capture in the r-process

    SciTech Connect

    Surman, Rebecca; Mclaughlin, Gail C; Mumpower, Matthew; Hix, William Raphael; Jones, K. L.

    2010-01-01

    Recently we have shown that neutron capture rates on nuclei near stability significantly influence the r-process abundance pattern. We discuss the different mechanisms by which the abundance pattern is sensitive to the capture rates and identify key nuclei whose rates are of particular im- portance. Here we consider nuclei in the A = 130 and A = 80 regions.

  10. Visual Field Asymmetry in Attentional Capture

    ERIC Educational Resources Information Center

    Du, Feng; Abrams, Richard A.

    2010-01-01

    The present study examined the spatial distribution of involuntary attentional capture over the two visual hemi-fields. A new experiment, and an analysis of three previous experiments showed that distractors in the left visual field that matched a sought-for target in color produced a much larger capture effect than identical distractors in the…

  11. Experiences in Personal Lecture Video Capture

    ERIC Educational Resources Information Center

    Chandra, Surendar

    2011-01-01

    The ability of lecture videos to capture the different modalities of a class interaction make them a good review tool. Multimedia capable devices are ubiquitous among contemporary students. Many lecturers are leveraging this popularity by distributing videos of lectures. They depend on the university to provide the video capture infrastructure.…

  12. Contingent Attentional Capture by Conceptually Relevant Images

    ERIC Educational Resources Information Center

    Wyble, Brad; Folk, Charles; Potter, Mary C.

    2013-01-01

    Attentional capture is an unintentional shift of visuospatial attention to the location of a distractor that is either highly salient, or relevant to the current task set. The latter situation is referred to as contingent capture, in that the effect is contingent on a match between characteristics of the stimuli and the task-defined…

  13. Encapsulated liquid sorbents for carbon dioxide capture.

    PubMed

    Vericella, John J; Baker, Sarah E; Stolaroff, Joshuah K; Duoss, Eric B; Hardin, James O; Lewicki, James; Glogowski, Elizabeth; Floyd, William C; Valdez, Carlos A; Smith, William L; Satcher, Joe H; Bourcier, William L; Spadaccini, Christopher M; Lewis, Jennifer A; Aines, Roger D

    2015-01-01

    Drawbacks of current carbon dioxide capture methods include corrosivity, evaporative losses and fouling. Separating the capture solvent from infrastructure and effluent gases via microencapsulation provides possible solutions to these issues. Here we report carbon capture materials that may enable low-cost and energy-efficient capture of carbon dioxide from flue gas. Polymer microcapsules composed of liquid carbonate cores and highly permeable silicone shells are produced by microfluidic assembly. This motif couples the capacity and selectivity of liquid sorbents with high surface area to facilitate rapid and controlled carbon dioxide uptake and release over repeated cycles. While mass transport across the capsule shell is slightly lower relative to neat liquid sorbents, the surface area enhancement gained via encapsulation provides an order-of-magnitude increase in carbon dioxide absorption rates for a given sorbent mass. The microcapsules are stable under typical industrial operating conditions and may be used in supported packing and fluidized beds for large-scale carbon capture. PMID:25652243

  14. Encapsulated liquid sorbents for carbon dioxide capture

    NASA Astrophysics Data System (ADS)

    Vericella, John J.; Baker, Sarah E.; Stolaroff, Joshuah K.; Duoss, Eric B.; Hardin, James O.; Lewicki, James; Glogowski, Elizabeth; Floyd, William C.; Valdez, Carlos A.; Smith, William L.; Satcher, Joe H.; Bourcier, William L.; Spadaccini, Christopher M.; Lewis, Jennifer A.; Aines, Roger D.

    2015-02-01

    Drawbacks of current carbon dioxide capture methods include corrosivity, evaporative losses and fouling. Separating the capture solvent from infrastructure and effluent gases via microencapsulation provides possible solutions to these issues. Here we report carbon capture materials that may enable low-cost and energy-efficient capture of carbon dioxide from flue gas. Polymer microcapsules composed of liquid carbonate cores and highly permeable silicone shells are produced by microfluidic assembly. This motif couples the capacity and selectivity of liquid sorbents with high surface area to facilitate rapid and controlled carbon dioxide uptake and release over repeated cycles. While mass transport across the capsule shell is slightly lower relative to neat liquid sorbents, the surface area enhancement gained via encapsulation provides an order-of-magnitude increase in carbon dioxide absorption rates for a given sorbent mass. The microcapsules are stable under typical industrial operating conditions and may be used in supported packing and fluidized beds for large-scale carbon capture.

  15. Isotope separation by photoselective dissociative electron capture

    DOEpatents

    Stevens, Charles G. [Pleasanton, CA

    1978-08-29

    A method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, .sup.235 UF.sub.6 is separated from a UF.sub.6 mixture by selective excitation followed by dissociative electron capture into .sup.235 UF.sub.5 - and F.

  16. Isotope separation by photoselective dissociative electron capture

    DOEpatents

    Stevens, C.G.

    1978-08-29

    Disclosed is a method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, [sup 235]UF[sub 6] is separated from a UF[sub 6] mixture by selective excitation followed by dissociative electron capture into [sup 235]UF[sub 5]- and F. 2 figs.

  17. Capture of irregular satellites at Jupiter

    SciTech Connect

    Nesvorný, David; Vokrouhlický, David; Deienno, Rogerio

    2014-03-20

    The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early solar system instability when encounters between the outer planets occurred. Nesvorný et al. already showed that the irregular satellites of Saturn, Uranus, and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encounters with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary disk is found to be (1.3-3.6) × 10{sup –8}. This is roughly enough to explain the observed population of jovian irregular moons. We also confirm Nesvorný et al.'s results for the irregular satellites of Saturn, Uranus, and Neptune.

  18. Covalent Organic Frameworks for CO2 Capture.

    PubMed

    Zeng, Yongfei; Zou, Ruqiang; Zhao, Yanli

    2016-04-01

    As an emerging class of porous crystalline materials, covalent organic frameworks (COFs) are excellent candidates for various applications. In particular, they can serve as ideal platforms for capturing CO2 to mitigate the dilemma caused by the greenhouse effect. Recent research achievements using COFs for CO2 capture are highlighted. A background overview is provided, consisting of a brief statement on the current CO2 issue, a summary of representative materials utilized for CO2 capture, and an introduction to COFs. Research progresses on: i) experimental CO2 capture using different COFs synthesized based on different covalent bond formations, and ii) computational simulation results of such porous materials on CO2 capture are summarized. Based on these experimental and theoretical studies, careful analyses and discussions in terms of the COF stability, low- and high-pressure CO2 uptake, CO2 selectivity, breakthrough performance, and CO2 capture conditions are provided. Finally, a perspective and conclusion section of COFs for CO2 capture is presented. Recent advancements in the field are highlighted and the strategies and principals involved are discussed. PMID:26924720

  19. Benchmarking a surrogate reaction for neutron capture

    SciTech Connect

    Hatarik, R.; Cizewski, J. A.; Hatarik, A. M.; O'Malley, P. D.; Bernstein, L. A.; Bleuel, D. L.; Burke, J. T.; Escher, J. E.; Lesher, S. R.; Gibelin, J.; Phair, L.; Rodriguez-Vieitez, E.; Goldblum, B. L.; Swan, T.; Wiedeking, M.

    2010-01-15

    {sup 171,173}Yb(d,p{gamma}) reactions are measured, with the goal of extracting the neutron capture cross-section ratio as a function of the neutron energy using the external surrogate ratio method. The cross-section ratios obtained are compared to the known neutron capture cross sections. Although the Weisskopf-Ewing limit is demonstrated not to apply for these low neutron energies, a prescription for deducing surrogate cross sections is presented. The surrogate cross-section ratios deduced from the {sup 171,173}Yb(d,p{gamma}) measurements agree with the neutron capture results within 15%.

  20. Station Commander Captures Unprecedented View of Comet

    NASA Video Gallery

    International Space Station Commander Dan Burbank captured spectacular imagery of Comet Lovejoy as seen from about 240 miles above the Earth’s horizon on Wednesday, Dec. 21. Burbank described se...

  1. Multiplexed programmable release of captured DNA.

    PubMed

    Kennedy-Darling, Julia; Holden, Matthew T; Shortreed, Michael R; Smith, Lloyd M

    2014-11-01

    Nucleic-acid hybridization is widely used for the specific capture of complementary sequences from complex samples. It is useful for both analytical methodologies, such as array hybridization (e.g. transcriptome analysis, genetic-variation analysis), and preparative strategies such as exome sequencing and sequence-specific proteome capture and analysis (PICh, HyCCAPP). It has not generally been possible to selectively elute particular captured subsequences, however, as the conditions employed for disruption of a duplex can lack the specificity needed to discriminate between different sequences. We show here that it is possible to bind and selectively release multiple sets of sequences by using toehold-mediated DNA branch migration. The strategy is illustrated for simple mixtures of oligonucleotides, for the sequence-specific capture and specific release of crosslinked yeast chromatin, and for the specific release of oligonucleotides hybridized to DNA microarrays. PMID:25157426

  2. In-plane payload capture using tethers

    NASA Astrophysics Data System (ADS)

    Williams, Paul; Blanksby, Chris; Trivailo, Pavel; Fujii, Hironori A.

    2005-11-01

    This paper presents a study on utilising space tether technology for the rendezvous and capture of payloads. Tethers are advantageous in space applications due to their low weight and extreme length and significant mass savings may be obtained compared to conventional propulsion systems. However, there are some significant challenges that face the designer of such a system. This paper addresses some of these challenges: (1) Matching the position and velocity of the tether tip for rendezvous with an incoming payload, (2) prolonging the rendezvous manoeuvre to allow maximum time for successful docking of the payload, (3) design of a capture mechanism that allows for errors in the tether tip velocity, (4) control of the post-capture dynamics of the tether, and (5) safety and failsafe design concerns. This paper presents control laws and numerical analysis for each of these challenges and demonstrates the feasibility of payload capture using tether technology.

  3. Capturing American black ducks in tidal waters

    USGS Publications Warehouse

    Harrison, M.K., Sr.; Haramis, G.M.; Jorde, D.G.; Stotts, D.B.

    2000-01-01

    We modified conventional, funnel-entrance dabbling duck bait traps to increase captures for banding of American Black Ducks (Anas rubripes) in tidal saltmarsh habitats of Smith Island, Maryland, one of the few remaining strongholds for breeding Black Ducks in the Chesapeake Bay. Traps and trapping techniques were adapted to tidal creeks and refined to improve capture rate, reduce mortality, and minimize interference by gulls. Best results were achieved by synchronizing trapping with predawn, low-tide foraging patterns of Black Ducks. Trap entrances were critical to retaining ducks, and use of loafing platforms reduced overall mortality to 3% of captures per year. We captured 3071 Black Ducks during the 14-year period, 1984-199

  4. Wire Capture Programs for Macintosh and IBM.

    ERIC Educational Resources Information Center

    Wiley, Gale

    1989-01-01

    Discusses wire capture programs (computer programs which gather and process wire services such as the Associated Press or United Press) for computer labs in journalism departments. Describes details of such programs for Macintosh, IBM, and IBM clones. (SR)

  5. Capture of planetesimals into a circumterrestrial swarm

    SciTech Connect

    Weidenschilling, S.J.

    1984-01-01

    The lunar origin model considered involves processing of protolunar material through a circumterrestrial swarm of particles. Once such a swarm has formed, it can gain mass by capturing infalling planetesimals and ejecta from giant impacts on the Earth, although the angular momentum supply from these sources remains a problem. Examined is the first stage of formation of a geocentric swarm by capture of planetesimals from initialy heliocentric orbits. The only plausible capture mechanism that is not dependent on very low approach velocities is the mutual collision of planetesimals passing within Earth's sphere of influence. This capture scenario was tested directly by many body numerical integration of planetesimal orbits in near Earth space. Results agree that the systematic contribution of angular momentum is insufficient to maintain an orbiting swarm under heavy bombardment. Thus, a circumterrestrial swarm can be formed rather easily, but is hard to sustain because the mean net angular momentum of a many body swarm is small.

  6. Data capture and processing. [for Space Station

    NASA Technical Reports Server (NTRS)

    Lyon, John; Smith, Gene; Carper, Richard

    1987-01-01

    A systems concept developed in response to the specific requirements imposed by the Space Station and affiliated instrumentation is described. Particular attention is given to those subsystems associated with initial data capture, handling, routing, and distribution control for return link data via the Tracking and Data Relay Satellite System. The conceived approach, designated the Customer Data and Operations System, includes a data interface facility and a data handling center whose functions are data capture, demultiplexing and routing, early preprocessing, and ancillary data handling.

  7. Design knowledge capture for the space station

    NASA Technical Reports Server (NTRS)

    Crouse, K. R.; Wechsler, D. B.

    1987-01-01

    The benefits of design knowledge availability are identifiable and pervasive. The implementation of design knowledge capture and storage using current technology increases the probability for success, while providing for a degree of access compatibility with future applications. The space station design definition should be expanded to include design knowledge. Design knowledge should be captured. A critical timing relationship exists between the space station development program, and the implementation of this project.

  8. Atomic electron correlation in nuclear electron capture

    NASA Technical Reports Server (NTRS)

    Chen, M. H.; Crasemann, B.

    1978-01-01

    The effect of electron-electron Coulomb correlation on orbital electron capture by the nucleus was treated by the multiconfigurational Hartree-Fock approach. The theoretical Be-7 L/K capture ratio was found to be 0.086, and the Ar-37 M/L ratio, 0.102. Both ratios were smaller than the independent particle predictions. Measurements exist for the Ar M/L ratio, and agreement between theory and experiment was excellent.

  9. CAPTURE OF TROJANS BY JUMPING JUPITER

    SciTech Connect

    Nesvorny, David; Vokrouhlicky, David; Morbidelli, Alessandro

    2013-05-01

    Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here, we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to {approx}5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the observed asymmetry in the number of leading and trailing Trojans. We find that the capture probability is (6-8) Multiplication-Sign 10{sup -7} for each particle in the original transplanetary disk, implying that the disk contained (3-4) Multiplication-Sign 10{sup 7} planetesimals with absolute magnitude H < 9 (corresponding to diameter D = 80 km for a 7% albedo). The disk mass inferred from this work, M{sub disk} {approx} 14-28 M{sub Earth}, is consistent with the mass deduced from recent dynamical simulations of the planetary instability.

  10. Capture of farmed Nile crocodiles (Crocodylus niloticus): comparison of physiological parameters after manual capture and after capture with electrical stunning.

    PubMed

    Pfitzer, S; Ganswindt, A; Fosgate, G T; Botha, P J; Myburgh, J G

    2014-09-27

    The electric stunner (e-stunner) is commonly used to handle Nile crocodiles (Crocodylus niloticus) on commercial farms in South Africa, but while it seems to improve handling and safety for the keepers, no information regarding physiological reactions to e-stunning is currently available. The aim of this study was therefore to compare various physiological parameters in farmed C niloticus captured either manually (noosing) or by using an e-stunner. A total of 45 crocodiles were captured at a South African farm by either e-stunning or noosing, and blood samples were taken immediately as well as four hours after capture. Parameters monitored were serum corticosterone, lactate, glucose, as well as alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase and creatine kinase. Lactate concentrations were significantly higher in noosed compared with e-stunned animals (P<0.001). No other blood parameter differed significantly between the two methods of capture. In addition, recorded capture time confirmed that noosing takes significantly longer time compared with e-stunning (P<0.001), overall indicating that e-stunning seems to be the better option for restraint of especially large numbers of crocodiles in a commercial setup because it is quicker, safer and did not cause a significant increase in any of the parameters measured. PMID:25096588

  11. Neutron capture cross section and capture gamma-ray spectra of 89Y

    NASA Astrophysics Data System (ADS)

    Katabuchi, Tatsuya; Okamiya, Tohomohiro; Yanagida, Shotaro; Mizumoto, Motoharu; Terada, Kazushi; Kimura, Atsushi; Iwamoto, Nobuyuki; Igashira, Masayuki

    2016-06-01

    The neutron capture cross section of 89Y was measured by the time-of-flight method in an energy range from 15 to 100 keV. A pulse-height weighting technique was applied to derive the capture yield. The absolute cross section was determined based on the standard reaciotn 197 Au(n, γ)198 Au reaction. The neutron capture γ-ray spectrum was derived by unfolding the pulse-height spectrum with detector response functions.

  12. Enhanced virome sequencing using targeted sequence capture

    PubMed Central

    Wylie, Todd N.; Wylie, Kristine M.; Herter, Brandi N.; Storch, Gregory A.

    2015-01-01

    Metagenomic shotgun sequencing (MSS) is an important tool for characterizing viral populations. It is culture independent, requires no a priori knowledge of the viruses in the sample, and may provide useful genomic information. However, MSS can lack sensitivity and may yield insufficient data for detailed analysis. We have created a targeted sequence capture panel, ViroCap, designed to enrich nucleic acid from DNA and RNA viruses from 34 families that infect vertebrate hosts. A computational approach condensed ∼1 billion bp of viral reference sequence into <200 million bp of unique, representative sequence suitable for targeted sequence capture. We compared the effectiveness of detecting viruses in standard MSS versus MSS following targeted sequence capture. First, we analyzed two sets of samples, one derived from samples submitted to a diagnostic virology laboratory and one derived from samples collected in a study of fever in children. We detected 14 and 18 viruses in the two sets, comprising 19 genera from 10 families, with dramatic enhancement of genome representation following capture enrichment. The median fold-increases in percentage viral reads post-capture were 674 and 296. Median breadth of coverage increased from 2.1% to 83.2% post-capture in the first set and from 2.0% to 75.6% in the second set. Next, we analyzed samples containing a set of diverse anellovirus sequences and demonstrated that ViroCap could be used to detect viral sequences with up to 58% variation from the references used to select capture probes. ViroCap substantially enhances MSS for a comprehensive set of viruses and has utility for research and clinical applications. PMID:26395152

  13. Last chance for carbon capture and storage

    NASA Astrophysics Data System (ADS)

    Scott, Vivian; Gilfillan, Stuart; Markusson, Nils; Chalmers, Hannah; Haszeldine, R. Stuart

    2013-02-01

    Anthropogenic energy-related CO2 emissions are higher than ever. With new fossil-fuel power plants, growing energy-intensive industries and new sources of fossil fuels in development, further emissions increase seems inevitable. The rapid application of carbon capture and storage is a much heralded means to tackle emissions from both existing and future sources. However, despite extensive and successful research and development, progress in deploying carbon capture and storage has stalled. No fossil-fuel power plants, the greatest source of CO2 emissions, are using carbon capture and storage, and publicly supported demonstration programmes are struggling to deliver actual projects. Yet, carbon capture and storage remains a core component of national and global emissions-reduction scenarios. Governments have to either increase commitment to carbon capture and storage through much more active market support and emissions regulation, or accept its failure and recognize that continued expansion of power generation from burning fossil fuels is a severe threat to attaining objectives in mitigating climate change.

  14. Multiplexed protein profiling by sequential affinity capture.

    PubMed

    Ayoglu, Burcu; Birgersson, Elin; Mezger, Anja; Nilsson, Mats; Uhlén, Mathias; Nilsson, Peter; Schwenk, Jochen M

    2016-04-01

    Antibody microarrays enable parallelized and miniaturized analysis of clinical samples, and have proven to provide novel insights for the analysis of different proteomes. However, there are concerns that the performance of such direct labeling and single antibody assays are prone to off-target binding due to the sample context. To improve selectivity and sensitivity while maintaining the possibility to conduct multiplexed protein profiling, we developed a multiplexed and semi-automated sequential capture assay. This novel bead-based procedure encompasses a first antigen capture, labeling of captured protein targets on magnetic particles, combinatorial target elution and a read-out by a secondary capture bead array. We demonstrate in a proof-of-concept setting that target detection via two sequential affinity interactions reduced off-target contribution, while lowered background and noise levels, improved correlation to clinical values compared to single binder assays. We also compared sensitivity levels with single binder and classical sandwich assays, explored the possibility for DNA-based signal amplification, and demonstrate the applicability of the dual capture bead-based antibody microarray for biomarker analysis. Hence, the described concept enhances the possibilities for antibody array assays to be utilized for protein profiling in body fluids and beyond. PMID:26935855

  15. EVOLUTION OF PROGENITORS FOR ELECTRON CAPTURE SUPERNOVAE

    SciTech Connect

    Takahashi, Koh; Umeda, Hideyuki; Yoshida, Takashi E-mail: umeda@astron.s.u-tokyo.ac.jp

    2013-07-01

    We provide progenitor models for electron capture supernovae (ECSNe) with detailed evolutionary calculation. We include minor electron capture nuclei using a large nuclear reaction network with updated reaction rates. For electron capture, the Coulomb correction of rates is treated and the contribution from neutron-rich isotopes is taken into account in each nuclear statistical equilibrium (NSE) composition. We calculate the evolution of the most massive super asymptotic giant branch stars and show that these stars undergo off-center carbon burning and form ONe cores at the center. These cores become heavier up to the critical mass of 1.367 M{sub Sun} and keep contracting even after the initiation of O+Ne deflagration. Inclusion of minor electron capture nuclei causes convective URCA cooling during the contraction phase, but the effect on the progenitor evolution is small. On the other hand, electron capture by neutron-rich isotopes in the NSE region has a more significant effect. We discuss the uniqueness of the critical core mass for ECSNe and the effect of wind mass loss on the plausibility of our models for ECSN progenitors.

  16. Neutron Capture Cross Sections for Radioactive Nuclei

    NASA Astrophysics Data System (ADS)

    Tonchev, Anton; Bedrossian, Peter; Escher, Jutta; Scielzo, Nicholas

    2015-10-01

    Accurate neutron-capture cross sections for radioactive nuclei near or far away from the line of beta stability are crucial for understanding the nucleosynthesis of heavy elements. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining observables that can constrain Hauser-Feshbach statistical model calculations of capture cross sections. Specifically, we will consider photon scattering, transfer reactions, and beta-delayed neutron emission. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes far from stability will be discussed. This work was performed under the auspices of US DOE by LLNL under contract DE-AC52-07NA27344. Funding was provided via the LDRD-ERD-069 project.

  17. Approach to magnetic neutron capture therapy

    SciTech Connect

    Kuznetsov, Anatoly A. . E-mail: spod@sky.chph.ras.ru; Podoynitsyn, Sergey N.; Filippov, Victor I.; Komissarova, Lubov Kh.; Kuznetsov, Oleg A.

    2005-11-01

    Purpose: The method of magnetic neutron capture therapy can be described as a combination of two methods: magnetic localization of drugs using magnetically targeted carriers and neutron capture therapy itself. Methods and Materials: In this work, we produced and tested two types of particles for such therapy. Composite ultradispersed ferro-carbon (Fe-C) and iron-boron (Fe-B) particles were formed from vapors of respective materials. Results: Two-component ultradispersed particles, containing Fe and C, were tested as magnetic adsorbent of L-boronophenylalanine and borax and were shown that borax sorption could be effective for creation of high concentration of boron atoms in the area of tumor. Kinetics of boron release into the physiologic solution demonstrate that ultradispersed Fe-B (10%) could be applied for an effective magnetic neutron capture therapy. Conclusion: Both types of the particles have high magnetization and magnetic homogeneity, allow to form stable magnetic suspensions, and have low toxicity.

  18. Rebuild of Capture Cavity 1 at Fermilab

    SciTech Connect

    Harms, E.; Arkan, T.; Borissov, E.; Dhanaraj, N.; Hocker, A.; Orlov, Y.; Peterson, T.; Premo, K.

    2014-01-01

    The front end of the proposed Advanced Superconducting Test Accelerator at Fermilab employs two single cavity cryomodules, known as 'Capture Cavity 1' and 'Capture Cavity 2', for the first stage of acceleration. Capture Cavity 1 was previously used as the accelerating structure for the A0 Photoinjector to a peak energy of ~14 MeV. In its new location a gradient of ~25 MV/m is required. This has necessitated a major rebuild of the cryomodule including replacement of the cavity with a higher gradient one. Retrofitting the cavity and making upgrades to the module required significant redesign. The design choices and their rationale, summary of the rebuild, and early test results are presented.

  19. Constant-parameter capture-recapture models

    USGS Publications Warehouse

    Brownie, C.; Hines, J.E.; Nichols, J.D.

    1986-01-01

    Jolly (1982, Biometrics 38, 301-321) presented modifications of the Jolly-Seber model for capture-recapture data, which assume constant survival and/or capture rates. Where appropriate, because of the reduced number of parameters, these models lead to more efficient estimators than the Jolly-Seber model. The tests to compare models given by Jolly do not make complete use of the data, and we present here the appropriate modifications, and also indicate how to carry out goodness-of-fit tests which utilize individual capture history information. We also describe analogous models for the case where young and adult animals are tagged. The availability of computer programs to perform the analysis is noted, and examples are given using output from these programs.

  20. Thermal Neutron Capture y's (CapGam)

    DOE Data Explorer

    The National Nuclear Data Center (NNDC) presents two tables showing energy and photon intensity with uncertainties of gamma rays as seen in thermal-neutron capture.  One table is organized in ascending order of gamma energy, and the second is organized by Z, A of the target. In the energy-ordered table the three strongest transitions are indicated in each case. The nuclide given is the target nucleus in the capture reaction. The gamma energies given are in keV. The gamma intensities given are relative to 100 for the strongest transition. %Iγ (per 100 n-captures) for the strongest transition is given, where known. All data are taken from the Evaluated Nuclear Structure Data File (ENSDF), a computer file of evaluated nuclear structure data and from the eXperimental Unevaluated Nuclear Data List (XUNDL). (Specialized Interface)

  1. Micromachined fragment capturer for biomedical applications

    NASA Astrophysics Data System (ADS)

    Choi, Young-Soo; Lee, Dong-Weon

    2011-11-01

    Due to changes in modern diet, a form of heart disease called chronic total occlusion has become a serious disease to be treated as an emergency. In this study, we propose a micromachined capturer that is designed and fabricated to collect plaque fragments generated during surgery to remove the thrombus. The fragment capturer consists of a plastic body made by rapid prototyping, SU-8 mesh structures using MEMS techniques, and ionic polymer metal composite (IPMC) actuators. An array of IPMC actuators combined with the SU-8 net structure was optimized to effectively collect plaque fragments. The evaporation of solvent through the actuator's surface was prevented using a coating of SU-8 and polydimethylsiloxane thin film on the actuator. This approach improved the available operating time of the IPMC, which primarily depends on solvent loss. Our preliminary results demonstrate the possibility of using the capturer for biomedical applications.

  2. Thermal-neutron capture in light nuclei

    SciTech Connect

    Raman, S.; Jurney, E.T.; Lynn, J.E.

    1996-10-01

    We have made considerable progress toward the goal of carrying out thermal-neutron capture {gamma}-ray measurements on all stable isotopes below A=60. Information processed till now has significantly augmented the existing knowledge on the detailed nuclear level structure of many light nuclides. Most of this knowledge comes from our {gamma}-ray energies, level placements, and branching ratios of secondary transitions between low-lying states. Spectroscopic information is also contained in the cross sections of the primary transitions originating from the capturing state. This is deduced from the success of ``direct`` theories of neutron capture for many nuclides, especially those of light and near closed-shell character. 23 refs, 1 tab, 3 figs.

  3. Selective gas capture via kinetic trapping.

    PubMed

    Kundu, Joyjit; Pascal, Tod; Prendergast, David; Whitelam, Stephen

    2016-08-21

    Conventional approaches to the capture of CO2 by metal-organic frameworks focus on equilibrium conditions, and frameworks that contain little CO2 in equilibrium are often rejected as carbon-capture materials. Here we use a statistical mechanical model, parameterized by quantum mechanical data, to suggest that metal-organic frameworks can be used to separate CO2 from a typical flue gas mixture when used under nonequilibrium conditions. The origin of this selectivity is an emergent gas-separation mechanism that results from the acquisition by different gas types of different mobilities within a crowded framework. The resulting distribution of gas types within the framework is in general spatially and dynamically heterogeneous. Our results suggest that relaxing the requirement of equilibrium can substantially increase the parameter space of conditions and materials for which selective gas capture can be effected. PMID:27435033

  4. Neutron capture by hook or by crook

    NASA Astrophysics Data System (ADS)

    Mosby, Shea

    2016-03-01

    The neutron capture reaction is a topic of fundamental interest for both heavy element (A>60) nucleosynthesis and applications in such fields as nuclear energy and defense. The full suite of interesting isotopes ranges from stable nuclei to the most exotic, and it is not possible to directly measure all the relevant reaction rates. The DANCE instrument at Los Alamos provides direct access to the neutron capture reaction for stable and long-lived nuclei, while Apollo coupled to HELIOS at Argonne has been developed as an indirect probe for cases where a direct measurement is impossible. The basic techniques and their implications will be presented, and the status of ongoing experimental campaigns to address neutron capture in the A=60 and A=100 mass regions will be discussed.

  5. Neutron transmission and capture of 241Am

    NASA Astrophysics Data System (ADS)

    Lampoudis, C.; Kopecky, S.; Plompen, A.; Schillebeeckx, P.; Wynants, R.; Gunsing, F.; Sage, C.; Bouland, O.; Noguere, G.

    2013-03-01

    A set of neutron transmission and capture experiments based on the Time Of Flight (TOF) technique, were performed in order to determine the 241Am capture cross section in the energy range from 0.01 eV to 1 keV. The GELINA facility of the Institute for Reference Materials and Measurements (IRMM) served as the neutron source. A pair of C6D6 liquid scintillators was used to register the prompt gamma rays emerging from the americium sample, while a Li-glass detector was used in the transmission setup. Results from the capture and transmission data acquired are consistent with each other, but appear to be inconsistent with the evaluated data files. Resonance parameters have been derived for the data up to the energy of 100 eV.

  6. Polarized Cold Neutron Capture in ^27Al

    NASA Astrophysics Data System (ADS)

    Balascuta, Septimiu

    2013-04-01

    The NPDGamma Experiment at the Spallation Neutron Source at ORNL is measuring the parity-odd correlation between the neutron spin and the direction of the emitted photon in the capture of cold neutrons on a 16-liter liquid parahydrogen target. The goal is to determine the strength of the weak nucleon-nucleon interaction. One of the main background contributions comes from the gamma rays produced by neutrons captured in the Al walls of the target vessel. To quantify this effect a commissioning experiment measured the parity-odd and parity-even asymmetries in the angular distribution of the gamma rays from the capture of polarized cold neutrons in a solid Al target. A status of the analysis of this experiment will be presented.

  7. Source Update Capture in Information Agents

    NASA Technical Reports Server (NTRS)

    Ashish, Naveen; Kulkarni, Deepak; Wang, Yao

    2003-01-01

    In this paper we present strategies for successfully capturing updates at Web sources. Web-based information agents provide integrated access to autonomous Web sources that can get updated. For many information agent applications we are interested in knowing when a Web source to which the application provides access, has been updated. We may also be interested in capturing all the updates at a Web source over a period of time i.e., detecting the updates and, for each update retrieving and storing the new version of data. Previous work on update and change detection by polling does not adequately address this problem. We present strategies for intelligently polling a Web source for efficiently capturing changes at the source.

  8. Electron capture in carbon dwarf supernovae

    NASA Technical Reports Server (NTRS)

    Mazurek, T. J.; Truran, J. W.; Cameron, A. G. W.

    1974-01-01

    The rates of electron capture on heavier elements under the extreme conditions predicted for dwarf star supernovae have been computed, incorporating modifications that seem to be indicated by present experimental results. An estimate of the maximum possible value of such rates is also given. The distribution of nuclei in nuclear statistical equilibrium has been calculated for the range of expected supernovae conditions, including the effects of the temperature dependence of nuclear partition functions. These nuclide abundance distributions are then used to compute nuclear equilibrium thermodynamic properties. The effects of the electron capture on such equilibrium matter are discussed. In the context of the 'carbon detonation' supernova model, the dwarf central density required to ensure core collapse to a neutron star configuration is found to be slightly higher than that obtained by Bruenn (1972) with the electron capture rates of Hansen (1966).-

  9. Three Crew Members Capture Intelsat VI

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Three crewmembers of mission STS-49 hold onto the 4.5 ton International Telecommunications Organization Satellite (INTELSAT) VI after a six- handed 'capture' was made minutes earlier during the mission's third extravehicular activity (EVA). From left to right: Mission Specialists(MS) Richard J. Hieb, Thomas D. Akers, and Pierre J. Thuot. The three prepare to attach the capture bar which is tethered to Hieb. Thuot is positioned on the Remote Manipulator System (RMS) arm, from which he had made two earlier unsuccessful grapple attempts on two- person EVA sessions. Ground controllers and crewmembers agreed that a third attempt, using three mission specialists in the payload bay (PLB) was the effort needed to accomplish the capture feat. Behind the three astronauts is the vertical perigee stage which will be attached to the Intelsat VI prior to its release from the PLB.

  10. Thermal Propulsion Capture System Heat Exchanger Design

    NASA Technical Reports Server (NTRS)

    Richard, Evan M.

    2016-01-01

    One of the biggest challenges of manned spaceflight beyond low earth orbit and the moon is harmful radiation that astronauts would be exposed to on their long journey to Mars and further destinations. Using nuclear energy has the potential to be a more effective means of propulsion compared to traditional chemical engines (higher specific impulse). An upper stage nuclear engine would allow astronauts to reach their destination faster and more fuel efficiently. Testing these engines poses engineering challenges due to the need to totally capture the engine exhaust. The Thermal Propulsion Capture System is a concept for cost effectively and safely testing Nuclear Thermal Engines. Nominally, hydrogen exhausted from the engine is not radioactive, but is treated as such in case of fuel element failure. The Thermal Propulsion Capture System involves injecting liquid oxygen to convert the hydrogen exhaust into steam. The steam is then cooled and condensed into liquid water to allow for storage. The Thermal Propulsion Capture System concept for ground testing of a nuclear powered engine involves capturing the engine exhaust to be cooled and condensed before being stored. The hydrogen exhaust is injected with liquid oxygen and burned to form steam. That steam must be cooled to saturation temperatures before being condensed into liquid water. A crossflow heat exchanger using water as a working fluid will be designed to accomplish this goal. Design a cross flow heat exchanger for the Thermal Propulsion Capture System testing which: Eliminates the need for water injection cooling, Cools steam from 5800 F to saturation temperature, and Is efficient and minimizes water requirement.

  11. Capturing significant events with neural networks.

    PubMed

    Szu, Harold; Hsu, Charles; Jenkins, Jeffrey; Willey, Jefferson; Landa, Joseph

    2012-05-01

    Smartphone video capture and transmission to the Web contributes to data pollution. In contrast, mammalian eyes sense all, capture only significant events, allowing us vividly recall the causalities. Likewise in our videos, we wish to skip redundancies and keep only significantly differences, as determined by real-time local medium filters. We construct a Picture Index (PI) of one's (center of gravity changes) among zeros (no changes) as Motion Organized Sparseness (MOS). Only non-overlapping time-ordered PI pair is admitted in the outer-product Associative Memory (AM). Another outer product between PI and its image builds Hetero-AM (HAM) for fault tolerant retrievals. PMID:22402410

  12. Ventricular capture by anodal pacemaker stimulation.

    PubMed

    Occhetta, Eraldo; Bortnik, Miriam; Marino, Paolo

    2006-05-01

    This report describes the case of an 86-year-old male with syncopal paroxysmal 2:1 atrioventricular block and a single chamber VVI pacemaker programmed to bipolar sensing and unipolar pacing. After recurrence of syncope, a complete loss of ventricular capture with regular ventricular sensing was observed on ECG; fluoroscopic examination suggested perforation of the right ventricle by the helix of the implanted screw-in lead. Reprogramming the pacemaker to bipolar pacing/sensing resulted in regular ventricular capture and sensing, suggesting effective anodal stimulation from the ring electrode permitting complete non-invasive palliation. PMID:16636000

  13. Protein Complex Purification by Affinity Capture.

    PubMed

    LaCava, John; Fernandez-Martinez, Javier; Hakhverdyan, Zhanna; Rout, Michael P

    2016-01-01

    Affinity capture has become a powerful technique for consistently purifying endogenous protein complexes, facilitating biochemical and biophysical assays on otherwise inaccessible biological assemblies, and enabling broader interactomic exploration. For this procedure, cells are broken and their contents separated and extracted into a solvent, permitting access to target macromolecular complexes thus released in solution. The complexes are specifically enriched from the extract onto a solid medium coupled with an affinity reagent-usually an antibody-that recognizes the target either directly or through an appended affinity tag, allowing subsequent characterization of the complex. Here, we discuss approaches and considerations for purifying endogenous yeast protein complexes by affinity capture. PMID:27371601

  14. Gadolinium as a Neutron Capture Therapy Agent

    NASA Astrophysics Data System (ADS)

    Shih, Jing-Luen Allen

    The clinical results of treating brain tumors with boron neutron capture therapy are very encouraging and researchers around the world are once again making efforts to develop this therapeutic modality. Boron-10 is the agent receiving the most attention for neutron capture therapy but ^{157}Gd is a nuclide that also holds interesting properties of being a neutron capture therapy agent. The objective of this study is to evaluate ^{157}Gd as a neutron capture therapy agent. In this study it is determined that tumor concentrations of about 300 mug ^{157}Gd/g tumor can be achieved in brain tumors with some FDA approved MRI contrast agents such as Gd-DTPA and Gd-DOTA, and up to 628 mug ^{157 }Gd/g tumor can be established in bone tumors with Gd-EDTMP. Monte Carlo calculations show that with only 250 ppm of ^{157}Gd in tumor, neutron capture therapy can deliver 2,000 cGy to a tumor of 2 cm diameter or larger with 5 times 10^{12} n/cm ^2 fluence at the tumor. Dose measurements which were made with films and TLD's in phantoms verified these calculations. More extended Monte Carlo calculations demonstrate that neutron capture therapy with Gd possesses comparable dose distribution to B neutron capture therapy. With 5 times 10^{12 } n/cm^2 thermal neutrons at the tumor, Auger electrons from the Gd produced an optical density enhancement on the films that is similar to the effect caused by about 300 cGy of Gd prompt gamma dose which will further enhance the therapeutic effects. A technique that combines brachytherapy with Gd neutron capture therapy has been evaluated. Monte Carlo calculations show that 5,000 cGy of prompt gamma dose can be delivered to a treatment volume of 40 cm^3 with a 3-plane implant of a total of 9 Gd needles. The tumor to normal tissue advantage of this method is as good as ^{60} Co brachytherapy. Measurements of prompt gamma dose with films and TLD-700's in a lucite phantom verify the Monte Carlo evaluation. A technique which displays the Gd

  15. A collapsible trap for capturing ruffe

    USGS Publications Warehouse

    Edwards, Andrew J.; Czypinski, Gary D.; Selgeby, James H.

    1998-01-01

    A modified version of the Windermere trap was designed, constructed, and tested for its effectiveness in capturing ruffe Gymnocephalus cernuus. The inexpensive, lightweight, collapsible trap was easily deployed and retrieved from a small boat. Field tests conducted at the St. Louis River estuary in western Lake Superior in spring 1995 and 1996 indicated that the trap was effective in capturing ruffe. Proportions of the ruffe in trap and bottom trawl catches were similar in 1995 and 1996. This trap could be a useful tool in surveillance, monitoring, or control programs for ruffe or similar species, either to augment existing sampling programs or especially in situations where gillnetting or bottom trawling are not feasible.

  16. Recent developments in shock-capturing schemes

    NASA Technical Reports Server (NTRS)

    Harten, Ami

    1991-01-01

    The development of the shock capturing methodology is reviewed, paying special attention to the increasing nonlinearity in its design and its relation to interpolation. It is well-known that higher-order approximations to a discontinuous function generate spurious oscillations near the discontinuity (Gibbs phenomenon). Unlike standard finite-difference methods which use a fixed stencil, modern shock capturing schemes use an adaptive stencil which is selected according to the local smoothness of the solution. Near discontinuities this technique automatically switches to one-sided approximations, thus avoiding the use of discontinuous data which brings about spurious oscillations.

  17. Real Time Telemetry Data Capture and Storage

    SciTech Connect

    DeAguero, James G.

    1997-05-14

    This program is used to capture telemetry data from remote instrumentation systems. The data can be captured at the rate of 1M bit per second. The data can come in one of several formats, NRZ, RZ, and Bi-Phase. The DECOM software takes the serial data stream and locks on to a unique code word. By tracking the code word the software can strip out the information. Thus the program can display the incoming data real time while saving the data to disk.

  18. Weigh-In-Motion Waveform Capture Systems

    Energy Science and Technology Software Center (ESTSC)

    2007-09-01

    Input data is generated from multiple weight sensor signals embedded in a thin weighing pad. This information is then reduced to total weight and position of a wheel rolling over the pad. This produces a signal which includes both the wheel weight and it inertial effects due to vehicle bounce, engine noise, and other mechanical vibrations. In order to extract accurate weight information of the wheel from the extraneous information, it is necessary to firstmore » capture the waveform and then perform a form of modal analysis. This program captures the above data and formats it into a useable form for analysis.« less

  19. Optimized Affinity Capture of Yeast Protein Complexes.

    PubMed

    LaCava, John; Fernandez-Martinez, Javier; Hakhverdyan, Zhanna; Rout, Michael P

    2016-01-01

    Here, we describe an affinity isolation protocol. It uses cryomilled yeast cell powder for producing cell extracts and antibody-conjugated paramagnetic beads for affinity capture. Guidelines for determining the optimal extraction solvent composition are provided. Captured proteins are eluted in a denaturing solvent (sodium dodecyl sulfate polyacrylamide gel electrophoresis sample buffer) for gel-based proteomic analyses. Although the procedures can be modified to use other sources of cell extract and other forms of affinity media, to date we have consistently obtained the best results with the method presented. PMID:27371596

  20. Systematic muon capture rates in PQRPA

    SciTech Connect

    Samana, A. R.; Sande, D.; Krmpotić, F.

    2015-05-15

    In this work we performed a systematic study of the inclusive muon capture rates for several nuclei with A < 60 using the Projected Random Quasi-particle Phase Approximation (PQRPA) as nuclear model, because it is the only RPA model that treats the Pauli Principle correctly. We reckon that the comparison between theory and data for the inclusive muon capture is not a fully satisfactory test on the nuclear model that is used. The exclusive muon transitions are more robust for such a purpose.

  1. Capturing birds with mist nets: A review

    USGS Publications Warehouse

    Keyes, B.E.; Grue, C.E.

    1982-01-01

    Herein we have tried to provide a comprehensive review of mist-netting techniques suitable for both novice and experienced netters. General mist-netting procedures and modifications developed by netters for particular bird species and habitats are included. Factors which influence capture success, including site selection, net specifications and placement, weather, and time of day, are discussed. Guidelines are presented for the care of netted birds and the use of mist-net data in the study of bird communities. The advantages of the use of mist nets over other methods of capturing birds are also discussed.

  2. Sulfur capture in combination bark boilers

    SciTech Connect

    Someshwar, A.V.; Jain, A.K. )

    1993-07-01

    A review of sulfur dioxide emission data for eight combination bark boilers in conjunction with the sulfur contents of the fuels reveals significant sulfur capture ranging from 10% to over 80% within the solid ash phase. Wood ash characteristics similar to activated carbon as well as the significant wood ash alkali oxide and carbonate fractions are believed responsible for the sulfur capture. Sulfur emissions from combination bark-fossil fuel firing are correlated to the sulfur input per ton of bark or wood residue fired.

  3. Real Time Telemetry Data Capture and Storage

    Energy Science and Technology Software Center (ESTSC)

    1997-05-14

    This program is used to capture telemetry data from remote instrumentation systems. The data can be captured at the rate of 1M bit per second. The data can come in one of several formats, NRZ, RZ, and Bi-Phase. The DECOM software takes the serial data stream and locks on to a unique code word. By tracking the code word the software can strip out the information. Thus the program can display the incoming data realmore » time while saving the data to disk.« less

  4. Radiative pion capture by C12.

    NASA Technical Reports Server (NTRS)

    Lam, W. C.; Gotow, K.; Macdonald, B.; Trower, W. P.; Anderson, D. K.

    1972-01-01

    The energy spectrum of neutrons from radiative pion capture by carbon is investigated. Radiative pion capture is identified by coincidence of a stop signal and a signal from one of six lead-glass gamma detectors when negative pions traverse a beam telescope and are stopped in a carbon target. The energy of the neutrons is measured using the time interval between a stop signal coincident with a gamma-counter signal and a signal from a liquid-oscillator neutron counter. Asymmetry in the neutron-photon angular correlation increases with neutron energy and is accounted for by direct neutron emission.

  5. Uranium Neutron Capture Gamma Cascade Generation and Transport Simulation for Capture Tank Response

    NASA Astrophysics Data System (ADS)

    Rosener, Thomas Jay

    1992-01-01

    A computer analysis has been performed to evaluate the energy dependent response of a capture tank to the gamma-ray cascades emitted from excited ^ {239}U. The GAMINT code was developed to simulate the decay of the ^{239 }U nucleus, formed in the ^{238}U(n,gamma)^{239 }U reaction, in order to provide the source spectrum for the complete analysis of the capture tank efficiency. This model determines the energies of the gamma-ray cascades, the order of emission of the gamma rays in a cascade, and the gamma-ray multiplicities by Monte Carlo techniques. A gamma-ray emission spectrum for the excited ^{239}U nucleus is generated. In the GAMINT code, known level data for ^{239}U is used below 1 MeV. A statistical approach based on the back-shifted Fermi gas model is used for the continuum level density. A single -particle model description for transition rates, with hindrance factors applied, is used to determine the gamma ray transition probabilities. Internal conversion probabilities are determined and the inclusion of this competing process suppresses the low energy portion of the gamma spectrum. A capture tank responds to the combined effect of the gamma rays of various energies from a cascade, after being transported through the material between the sample and the capture tank. Examined is the energy deposition, in a capture tank, by the cascades generated from resonant and off-resonant capture in a ^{238 }U sample. Internal conversion has a negligible effect on the average cascade energy deposited in the tank. Off -resonant (volumetric) capture deposits, on the average, less energy than resonant (surface) capture in the capture tank as a result of self-shielding of the gamma rays in the capture sample.

  6. Broken Expectations: Violation of Expectancies, Not Novelty, Captures Auditory Attention

    ERIC Educational Resources Information Center

    Vachon, Francois; Hughes, Robert W.; Jones, Dylan M.

    2012-01-01

    The role of memory in behavioral distraction by auditory attentional capture was investigated: We examined whether capture is a product of the novelty of the capturing event (i.e., the absence of a recent memory for the event) or its violation of learned expectancies on the basis of a memory for an event structure. Attentional capture--indicated…

  7. Dynamics of RF captured cooled proton beams

    SciTech Connect

    Kells, W.; Mills, F.

    1983-01-01

    In the course of electron cooling experiments at the Electron Cooling Ring (ECR) at Fermilab, several peculiar features of the longitudinal phase space of cold protons (200 MeV) captured in RF buckets were observed. Here we present the experimental facts, present a simple theory, and summarize computer simulation results which support the theory and facts.

  8. Context-Dependent Control over Attentional Capture

    ERIC Educational Resources Information Center

    Cosman, Joshua D.; Vecera, Shaun P.

    2013-01-01

    A number of studies have demonstrated that the likelihood of a salient item capturing attention is dependent on the "attentional set" an individual employs in a given situation. The instantiation of an attentional set is often viewed as a strategic, voluntary process, relying on working memory systems that represent immediate task priorities.…

  9. Target Capture during Mos1 Transposition*

    PubMed Central

    Pflieger, Aude; Jaillet, Jerôme; Petit, Agnès; Augé-Gouillou, Corinne; Renault, Sylvaine

    2014-01-01

    DNA transposition contributes to genomic plasticity. Target capture is a key step in the transposition process, because it contributes to the selection of new insertion sites. Nothing or little is known about how eukaryotic mariner DNA transposons trigger this step. In the case of Mos1, biochemistry and crystallography have deciphered several inverted terminal repeat-transposase complexes that are intermediates during transposition. However, the target capture complex is still unknown. Here, we show that the preintegration complex (i.e., the excised transposon) is the only complex able to capture a target DNA. Mos1 transposase does not support target commitment, which has been proposed to explain Mos1 random genomic integrations within host genomes. We demonstrate that the TA dinucleotide used as the target is crucial both to target recognition and in the chemistry of the strand transfer reaction. Bent DNA molecules are better targets for the capture when the target DNA is nicked two nucleotides apart from the TA. They improve strand transfer when the target DNA contains a mismatch near the TA dinucleotide. PMID:24269942

  10. Diffusive capture process on complex networks

    NASA Astrophysics Data System (ADS)

    Lee, Sungmin; Yook, Soon-Hyung; Kim, Yup

    2006-10-01

    We study the dynamical properties of a diffusing lamb captured by a diffusing lion on the complex networks with various sizes of N . We find that the lifetime ⟨T⟩ of a lamb scales as ⟨T⟩˜N and the survival probability S(N→∞,t) becomes finite on scale-free networks with degree exponent γ>3 . However, S(N,t) for γ<3 has a long-living tail on tree-structured scale-free networks and decays exponentially on looped scale-free networks. This suggests that the second moment of degree distribution ⟨k2⟩ is the relevant factor for the dynamical properties in the diffusive capture process. We numerically find that the normalized number of capture events at a node with degree k , n(k) , decreases as n(k)˜k-σ . When γ<3 , n(k) still increases anomalously for k≈kmax , where kmax is the maximum value of k of given networks with size N . We analytically show that n(k) satisfies the relation n(k)˜k2P(k) for any degree distribution P(k) and the total number of capture events Ntot is proportional to ⟨k2⟩ , which causes the γ -dependent behavior of S(N,t) and ⟨T⟩ .

  11. Capture and fission with DANCE and NEUANCE

    DOE PAGESBeta

    Jandel, M.; Baramsai, B.; Bond, E.; Rusev, G.; Walker, C.; Bredeweg, T. A.; Chadwick, M. B.; Couture, A.; Fowler, M. M.; Hayes, A.; et al

    2015-12-23

    A summary of the current and future experimental program at DANCE is presented. Measurements of neutron capture cross sections are planned for many actinide isotopes with the goal to reduce the present uncertainties in nuclear data libraries. Detailed studies of capture gamma rays in the neutron resonance region will be performed in order to derive correlated data on the de-excitation of the compound nucleus. New approaches on how to remove the DANCE detector response from experimental data and retain the correlations between the cascade gamma rays are presented. Studies on 235U are focused on quantifying the population of short-lived isomericmore » states in 236U after neutron capture. For this purpose, a new neutron detector array NEUANCE is under construction. It will be installed in the central cavity of the DANCE array and enable the highly efficient tagging of fission and capture events. In addition, developments of fission fragment detectors are also underway to expand DANCE capabilities to measurements of fully correlated data on fission observables.« less

  12. Historic Methods for Capturing Magnetic Field Images

    NASA Astrophysics Data System (ADS)

    Kwan, Alistair

    2016-03-01

    I investigated two late 19th-century methods for capturing magnetic field images from iron filings for historical insight into the pedagogy of hands-on physics education methods, and to flesh out teaching and learning practicalities tacit in the historical record. Both methods offer opportunities for close sensory engagement in data-collection processes.

  13. CAPTURING CO2 WITH MGO AEROGELS

    EPA Science Inventory

    CO2 capture from flue gas requires that the adsorbent be active at relatively low CO2 concentrations (3 – 13 vol%), high temperatures (~ 250ºC), and in the presence of many other gas species. These conditions will be simulated in the student designed reactor. The...

  14. Capturing spatial attention with multisensory cues.

    PubMed

    Santangelo, Valerio; Ho, Cristy; Spence, Charles

    2008-04-01

    We assessed the influence ofmultisensory interactions on the exogenous orienting of spatial attention by comparing the ability of auditory, tactile, and audiotactile exogenous cues to capture visuospatial attention under conditions of no perceptual load versus high perceptual load. In Experiment 1, participants discriminated the elevation of visual targets preceded by either unimodal or bimodal cues under conditions of either a high perceptual load (involving the monitoring of a rapidly presented central stream of visual letters for occasionally presented target digits) or no perceptual load (when the central stream was replaced by a fixation point). All of the cues captured spatial attention in the no-load condition, whereas only the bimodal cues captured visuospatial attention in the high-load condition. In Experiment 2, we ruled out the possibility that the presentation of any changing stimulus at fixation (i.e., a passively monitored stream of letters) would eliminate exogenous orienting, which instead appears to be a consequence of high perceptual load conditions (Experiment 1). These results demonstrate that multisensory cues capture spatial attention more effectively than unimodal cues under conditions of concurrent perceptual load. PMID:18488658

  15. Salmonella capture using orbiting magnetic microbeads

    NASA Astrophysics Data System (ADS)

    Owen, Drew; Ballard, Matthew; Mills, Zachary; Hanasoge, Srinivas; Hesketh, Peter; Alexeev, Alexander

    2014-11-01

    Using three-dimensional simulations and experiments, we examine capture of salmonella from a complex fluid sample flowing through a microfluidic channel. Capture is performed using orbiting magnetic microbeads, which can easily be extracted from the system for analysis after salmonella capture. Numerical simulations are used to model the dynamics of the system, which consists of a microchannel filled with a viscous fluid, model salmonella, magnetic microbeads and a series of angled parallel ridges lining the top of the microchannel. Simulations provide a statistical measure of the ability of the system to capture target salmonella. Our modeling findings guide the design of a lab-on-a-chip experimental device to be used for the detection of salmonella from complex food samples, allowing for the detection of the bacteria at the food source and preventing the consumption of contaminated food. Such a device can be used as a generic platform for the detection of a variety of biomaterials from complex fluids. This work is supported by a grant from the United States Department of Agriculture.

  16. Incremental learning for automated knowledge capture.

    SciTech Connect

    Benz, Zachary O.; Basilico, Justin Derrick; Davis, Warren Leon,; Dixon, Kevin R.; Jones, Brian S.; Martin, Nathaniel; Wendt, Jeremy Daniel

    2013-12-01

    People responding to high-consequence national-security situations need tools to help them make the right decision quickly. The dynamic, time-critical, and ever-changing nature of these situations, especially those involving an adversary, require models of decision support that can dynamically react as a situation unfolds and changes. Automated knowledge capture is a key part of creating individualized models of decision making in many situations because it has been demonstrated as a very robust way to populate computational models of cognition. However, existing automated knowledge capture techniques only populate a knowledge model with data prior to its use, after which the knowledge model is static and unchanging. In contrast, humans, including our national-security adversaries, continually learn, adapt, and create new knowledge as they make decisions and witness their effect. This artificial dichotomy between creation and use exists because the majority of automated knowledge capture techniques are based on traditional batch machine-learning and statistical algorithms. These algorithms are primarily designed to optimize the accuracy of their predictions and only secondarily, if at all, concerned with issues such as speed, memory use, or ability to be incrementally updated. Thus, when new data arrives, batch algorithms used for automated knowledge capture currently require significant recomputation, frequently from scratch, which makes them ill suited for use in dynamic, timecritical, high-consequence decision making environments. In this work we seek to explore and expand upon the capabilities of dynamic, incremental models that can adapt to an ever-changing feature space.

  17. Porphyrins for boron neutron capture therapy

    DOEpatents

    Miura, Michiko; Gabel, Detlef

    1990-01-01

    Novel compounds for treatment of brain tumors in Boron Neutron Capture Therapy are disclosed. A method for preparing the compounds as well as pharmaceutical compositions containing said compounds are also disclosed. The compounds are water soluble, non-toxic and non-labile boronated porphyrins which show significant uptake and retention in tumors.

  18. STEREO Captures Fastest CME to Date

    NASA Video Gallery

    This movie shows a coronal mass ejection (CME) on the sun from July 22, 2012 at 10:00 PM EDT until 2 AM on July 23 as captured by NASA's Solar TErrestrial RElations Observatory-Ahead (STEREO-A). Be...

  19. Persistence of Value-Driven Attentional Capture

    ERIC Educational Resources Information Center

    Anderson, Brian A.; Yantis, Steven

    2013-01-01

    Stimuli that have previously been associated with the delivery of reward involuntarily capture attention when presented as unrewarded and task-irrelevant distractors in a subsequent visual search task. It is unknown how long such effects of reward learning on attention persist. One possibility is that value-driven attentional biases are plastic…

  20. Capture and fission with DANCE and NEUANCE

    NASA Astrophysics Data System (ADS)

    Jandel, M.; Baramsai, B.; Bond, E.; Rusev, G.; Walker, C.; Bredeweg, T. A.; Chadwick, M. B.; Couture, A.; Fowler, M. M.; Hayes, A.; Kawano, T.; Mosby, S.; Stetcu, I.; Taddeucci, T. N.; Talou, P.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.

    2015-12-01

    A summary of the current and future experimental program at DANCE is presented. Measurements of neutron capture cross sections are planned for many actinide isotopes with the goal to reduce the present uncertainties in nuclear data libraries. Detailed studies of capture gamma rays in the neutron resonance region will be performed in order to derive correlated data on the de-excitation of the compound nucleus. New approaches on how to remove the DANCE detector response from experimental data and retain the correlations between the cascade gamma rays are presented. Studies on 235U are focused on quantifying the population of short-lived isomeric states in 236U after neutron capture. For this purpose, a new neutron detector array NEUANCE is under construction. It will be installed in the central cavity of the DANCE array and enable the highly efficient tagging of fission and capture events. In addition, developments of fission fragment detectors are also underway to expand DANCE capabilities to measurements of fully correlated data on fission observables.

  1. CO2 Capture with Enzyme Synthetic Analogue

    SciTech Connect

    Cordatos, Harry

    2010-03-01

    Project overview provides background on carbonic anhydrase transport mechanism for CO2 in the human body and proposed approach for ARPA-E project to create a synthetic enzyme analogue and utilize it in a membrane for CO2 capture from flue gas.

  2. Water surface capturing by image processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An alternative means of measuring the water surface interface during laboratory experiments is processing a series of sequentially captured images. Image processing can provide a continuous, non-intrusive record of the water surface profile whose accuracy is not dependent on water depth. More trad...

  3. Historic Methods for Capturing Magnetic Field Images

    ERIC Educational Resources Information Center

    Kwan, Alistair

    2016-01-01

    I investigated two late 19th-century methods for capturing magnetic field images from iron filings for historical insight into the pedagogy of hands-on physics education methods, and to flesh out teaching and learning practicalities tacit in the historical record. Both methods offer opportunities for close sensory engagement in data-collection…

  4. 46 CFR 67.134 - Captured vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Captured vessels. 67.134 Section 67.134 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DOCUMENTATION AND MEASUREMENT OF VESSELS DOCUMENTATION OF VESSELS Application for Special Qualifications for Vessel Documentation § 67.134...

  5. 46 CFR 67.134 - Captured vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Captured vessels. 67.134 Section 67.134 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DOCUMENTATION AND MEASUREMENT OF VESSELS DOCUMENTATION OF VESSELS Application for Special Qualifications for Vessel Documentation § 67.134...

  6. 46 CFR 67.134 - Captured vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Captured vessels. 67.134 Section 67.134 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DOCUMENTATION AND MEASUREMENT OF VESSELS DOCUMENTATION OF VESSELS Application for Special Qualifications for Vessel Documentation § 67.134...

  7. 46 CFR 67.134 - Captured vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Captured vessels. 67.134 Section 67.134 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DOCUMENTATION AND MEASUREMENT OF VESSELS DOCUMENTATION OF VESSELS Application for Special Qualifications for Vessel Documentation § 67.134...

  8. 46 CFR 67.134 - Captured vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Captured vessels. 67.134 Section 67.134 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DOCUMENTATION AND MEASUREMENT OF VESSELS DOCUMENTATION OF VESSELS Application for Special Qualifications for Vessel Documentation § 67.134...

  9. Capture and fission with DANCE and NEUANCE

    SciTech Connect

    Jandel, M.; Baramsai, B.; Bond, E.; Rusev, G.; Walker, C.; Bredeweg, T. A.; Chadwick, M. B.; Couture, A.; Fowler, M. M.; Hayes, A.; Kawano, T.; Mosby, S.; Stetcu, I.; Taddeucci, T. N.; Talou, P.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.

    2015-12-23

    A summary of the current and future experimental program at DANCE is presented. Measurements of neutron capture cross sections are planned for many actinide isotopes with the goal to reduce the present uncertainties in nuclear data libraries. Detailed studies of capture gamma rays in the neutron resonance region will be performed in order to derive correlated data on the de-excitation of the compound nucleus. New approaches on how to remove the DANCE detector response from experimental data and retain the correlations between the cascade gamma rays are presented. Studies on 235U are focused on quantifying the population of short-lived isomeric states in 236U after neutron capture. For this purpose, a new neutron detector array NEUANCE is under construction. It will be installed in the central cavity of the DANCE array and enable the highly efficient tagging of fission and capture events. In addition, developments of fission fragment detectors are also underway to expand DANCE capabilities to measurements of fully correlated data on fission observables.

  10. U.S. Spacesuit Knowledge Capture

    NASA Technical Reports Server (NTRS)

    Chullen, Cinda; Thomas, Ken; McMann, Joe; Dolan, Kristi; Bitterly, Rose; Lewis, Cathleen

    2010-01-01

    The ability to learn from both the mistakes and successes of the past is vital to assuring success in the future. Due to the close physical interaction between spacesuit systems and human beings as users, spacesuit technology and usage lends itself rather uniquely to the benefits realized from the skillful organization of historical information; its dissemination; the collection and identification of artifacts; and the education of individuals and groups working in the field. The National Aeronautics and Space Administration (NASA), other organizations and individuals have been performing United States (U.S.) spacesuit knowledge capture since the beginning of space exploration. Avenues used to capture the knowledge have included publication of reports; conference presentations; specialized seminars; and classes usually given by veterans in the field. Recently, the effort has been more concentrated and formalized whereby a new avenue of spacesuit knowledge capture has been added to the archives through which videotaping occurs, engaging both current and retired specialists in the field presenting technical scope specifically for education and preservation of knowledge. Now with video archiving, all these avenues of learning can be brought to life with the real experts presenting their wealth of knowledge on screen for future learners to enjoy. U.S. spacesuit knowledge capture topics have included lessons learned in spacesuit technology, experience from the Gemini, Apollo, Skylab and Shuttle programs, hardware certification, design, development and other program components, spacesuit evolution and experience, failure analysis and resolution, and aspects of program management. Concurrently, U.S. spacesuit knowledge capture activities have progressed to a level where NASA, the National Air and Space Museum (NASM), Hamilton Sundstrand (HS) and the spacesuit community are now working together to provide a rather closed-looped spacesuit knowledge capture system which

  11. Properties of Earth's temporarily-captured flybys

    NASA Astrophysics Data System (ADS)

    Fedorets, Grigori; Granvik, Mikael

    2014-11-01

    In addition to the Moon, a population of small temporarily-captured NEOs is predicted to orbit the Earth. The definition of a natural Earth satellite is that it is on an elliptic geocentric orbit within 0.03 au from the Earth. The population is further divided into temporarily-captured orbiters (TCOs, or minimoons, making at least one full revolution around the Earth in a coordinate system co-rotating with the Sun) and temporarily-captured flybys (TCFs) which fail to make a full revolution, but are temporarily on an elliptic orbit around the Earth. Only one minimoon has been discovered to date, but it is expected that next generation surveys will be able to detect these objects regularly.Granvik et al. (2012) performed an extensive analysis of the behaviour of these temporarily-captured objects. One of the main results was that at any given moment there is at least one 1-meter-diameter minimoon in orbit around the Earth. However, the results of Granvik et al. (2012) raised questions considering the NES population such as the bimodality of the capture duration distribution and a distinctive lack of test particles within Earth's Hill sphere, which requires investigating the statistical properties also of the TCF population.In this work we confirm the population characteristics for minimoons described by Granvik et al. (2012), and extend the analysis to TCFs. For the calculations we use a Bulirsch-Stoer integrator implemented in the OpenOrb software package (Granvik et al. 2009). We study, e.g., the capture statistics, residence-time distributions, and steady-state properties of TCFs. Our preliminary results indicate that TCFs may be suitable targets for asteroid-redirect missions. More detailed knowledge of the TCF population will also improve our understanding of the link between temporarily-captured objects and NEOs in general.References: Granvik et al. (2009) MPS 44(12), 1853-1861; Granvik et al. (2012) Icarus 218, 262-277.

  12. Annual Report: Carbon Capture (30 September 2012)

    SciTech Connect

    Luebke, David; Morreale, Bryan; Richards, George; Syamlal, Madhava

    2014-04-16

    Capture of carbon dioxide (CO{sub 2}) is a critical component in reducing greenhouse gas emissions from fossil fuel-based processes. The Carbon Capture research to be performed is aimed at accelerating the development of efficient, cost-effective technologies which meet the post-combustion programmatic goal of capture of 90% of the CO{sub 2} produced from an existing coal-fired power plant with less than a 35% increase in the cost of electricity (COE), and the pre-combustion goal of 90% CO{sub 2} capture with less than a 10% increase in COE. The specific objective of this work is to develop innovative materials and approaches for the economic and efficient capture of CO{sub 2} from coal-based processes, and ultimately assess the performance of promising technologies at conditions representative of field application (i.e., slip stream evaluation). The Carbon Capture research includes seven core technical research areas: post-combustion solvents, sorbents, and membranes; pre-combustion solvents, sorbents, and membranes; and oxygen (O{sub 2}) production. The goal of each of these tasks is to develop advanced materials and processes that are able to reduce the energy penalty and cost of CO{sub 2} (or O{sub 2}) separation over conventional technologies. In the first year of development, materials will be examined by molecular modeling, and then synthesized and experimentally characterized at lab scale. In the second year, they will be tested further under ideal conditions. In the third year, they will be tested under realistic conditions. The most promising materials will be tested at the National Carbon Capture Center (NCCC) using actual flue or fuel gas. Systems analyses will be used to determine whether or not materials developed are likely to meet the Department of Energy (DOE) COE targets. Materials which perform well and appear likely to improve in performance will be licensed for further development outside of the National Energy Technology Laboratory (NETL

  13. Minimizing capture-related stress on white-tailed deer with a capture collar

    USGS Publications Warehouse

    DelGiudice, G.D.; Kunkel, K.E.; Mech, L.D.; Seal, U.S.

    1990-01-01

    We compared the effect of 3 capture methods for white-tailed deer (Odocoileus virginianus) on blood indicators of acute excitement and stress from 1 February to 20 April 1989. Eleven adult females were captured by Clover trap or cannon net between 1 February and 9 April 1989 in northeastern Minnesota [USA]. These deer were fitted with radio-controlled capture collars, and 9 deer were recaptured 7-33 days later. Trapping method affected serum cortisol (P < 0.0001), hemoglobin (Hb) (P < 0.06), and packed cell volume (PCV) (P < 0.07). Cortisol concentrations were lower (P < 0.0001) in capture-collared deer (0.54 .+-. 0.07 [SE] .mu.g/dL) compared to Clover-trapped (4.37 .+-. 0.69 .mu.g/dL) and cannon-netted (3.88 .+-. 0.82 .mu.g/dL) deer. Capture-collared deer were minimally stressed compared to deer captured by traditional methods. Use of the capture collar should permit more accurate interpretation of blood profiles of deer for assessement of condition and general health.

  14. TARGET: Rapid Capture of Process Knowledge

    NASA Technical Reports Server (NTRS)

    Ortiz, C. J.; Ly, H. V.; Saito, T.; Loftin, R. B.

    1993-01-01

    TARGET (Task Analysis/Rule Generation Tool) represents a new breed of tool that blends graphical process flow modeling capabilities with the function of a top-down reporting facility. Since NASA personnel frequently perform tasks that are primarily procedural in nature, TARGET models mission or task procedures and generates hierarchical reports as part of the process capture and analysis effort. Historically, capturing knowledge has proven to be one of the greatest barriers to the development of intelligent systems. Current practice generally requires lengthy interactions between the expert whose knowledge is to be captured and the knowledge engineer whose responsibility is to acquire and represent the expert's knowledge in a useful form. Although much research has been devoted to the development of methodologies and computer software to aid in the capture and representation of some types of knowledge, procedural knowledge has received relatively little attention. In essence, TARGET is one of the first tools of its kind, commercial or institutional, that is designed to support this type of knowledge capture undertaking. This paper will describe the design and development of TARGET for the acquisition and representation of procedural knowledge. The strategies employed by TARGET to support use by knowledge engineers, subject matter experts, programmers and managers will be discussed. This discussion includes the method by which the tool employs its graphical user interface to generate a task hierarchy report. Next, the approach to generate production rules for incorporation in and development of a CLIPS based expert system will be elaborated. TARGET also permits experts to visually describe procedural tasks as a common medium for knowledge refinement by the expert community and knowledge engineer making knowledge consensus possible. The paper briefly touches on the verification and validation issues facing the CLIPS rule generation aspects of TARGET. A description of

  15. Neutron capture measurements for nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Reifarth, Rene

    2005-04-01

    Almost all of the heavy elements are produced via neutron capture reactions in a multitude of stellar production sites. The predictive power of the underlying stellar models is currently limited because they contain poorly constrained physics components such as convection, rotation or magnetic fields. Neutron captures measurements on heavy radioactive isotopes provide a unique opportunity to largely improve these physics components, and thereby address important questions of nuclear astrophysics. Such species are branch-points in the otherwise uniquely defined path of subsequent n-captures along the s-process path in the valley of stability. These branch points reveal themselves through unmistakable signatures recovered from pre-solar meteoritic grains that originate in individual element producing stars. Measurements on radioactive isotopes for neutron energies in the keV region represent a stringent challenge for further improvements of experimental techniques. This holds true for the neutron sources, the detection systems and the technology to handle radioactive material. Though the activation method or accelerator mass spectroscopy of the reaction products could be applied in a limited number of cases, Experimental facilities like DANCE at LANL, USA and n-TOF at CERN, Switzerland are addressing the need for such measurements on the basis of the more universal method of detecting the prompt capture gamma-rays, which is required for the application of neutron time-of-flight (TOF) techniques. With a strongly optimized neutron facility at the Rare Isotope Accelerator (RIA) isotopes with half-lives down to tens of days could be investigated, while present facilities require half-lives of a few hundred days. Recent neutron capture experiments on radioactive isotopes with relevance for nuclear astrophysics and possibilities for future experimental setups will be discussed during the talk.

  16. Continuum capture in the three-body problem

    SciTech Connect

    Sellin, I A

    1980-01-01

    The three-body problem, especially the problem of electron capture to the continuum in heavy particle collisions is reviewed. Major topics covered include: second born-induced asymmetry in electron capture to the continuum; historical context, links to other tests of atomic scattering theory; experiments characterizing the velocity distribution of ECC electrons; other atomic physics tests of high velocity Born expansions; atom capture; capture by positrons; and pion capture to the continuum. (GHT)

  17. Nanoroughened Surfaces for Efficient Capture of Circulating Tumor Cells without Using Capture Antibodies

    PubMed Central

    Chen, Weiqiang; Weng, Shinuo; Zhang, Feng; Allen, Steven; Li, Xiang; Bao, Liwei; Lam, Raymond H. W.; Macoska, Jill A.; Merajver, Sofia D.; Fu, Jianping

    2014-01-01

    Circulating tumor cells (CTCs) detached from both primary and metastatic lesions represent a potential alternative to invasive biopsies as a source of tumor tissue for the detection, characterization and monitoring of cancers. Here we report a simple yet effective strategy for capturing CTCs without using capture antibodies. Our method uniquely utilized the differential adhesion preference of cancer cells to nanorough surfaces when compared to normal blood cells and thus did not depend on their physical size or surface protein expression, a significant advantage as compared to other existing CTC capture techniques. PMID:23194329

  18. Eureka! Aerogel capture of meteoroids in space

    NASA Technical Reports Server (NTRS)

    Brownlee, D. E.; Horz, F.; Hrubsch, L.; Mcdonnell, J. A. M.; Tsou, P.; Williams, J.

    1994-01-01

    Light gas gun studies have shown that 6 km/s solid mineral and glass test particles can be successively captured in 0.05 g cm(exp -3) aerogel without severe heating or fragmentation. In spite of this work, there has been uncertainty in the performance of aerogel for hypervelocity capture of real meteoroids. Natural impacts differ from simulations in that the particles are likely to be structurally weak and they typically impact at higher velocity that can be simulated in the laboratory. We are fortunate now to have had two successful capture experiments using aerogel exposed in space. These experiments provide fundamental data for the assessment of the value of silica aerogel for capture of hypervelocity meteoroids from spacecraft. The first experiment used 0.02 g cm(exp -3) aerogel flown on the lid of a Shuttle Get Away Special canister. During its 9 day exposure, the 0.165 m(exp 2) of aerogel in this Sample Return Experiment (SRE) captured two long 'carrot-shaped' tracks and one highly fractured bowl shaped 'crater'. The second collection was with 0.04 m(exp 2) of 0.05 g cm(exp -3) aerogel exposed on ESA's Eureca freeflying spacecraft that was exposed for 11 months before recovery by the Shuttle. The Eureca aerogel exposure consisted of four 10x10 cm module trays that were part of the TiCCE meteoroid collector built by the University of Kent at Canterbury. To date we have found ten 'carrot-shaped' tracks and two 'craters' on this experiment. The longest tracks in both exposures are over 2 mm long. Two of the TiCCE modules had a 0.1 micron Al film suspended a millimeter above the aerogel. On these modules several of the projectiles fragmented during passage through the film producing fields of carrot shaped tracks from the resulting miniature 'meteor' shower. Most of the tracks in these showers have observable particles at their ends. We have extracted one of the carrot track meteoroids and mounted it in epoxy for sectioning. So far the examination of these 14

  19. Carbon Dioxide Capture: Covalent Organic Frameworks for CO2 Capture (Adv. Mater. 15/2016).

    PubMed

    Zeng, Yongfei; Zou, Ruqiang; Zhao, Yanli

    2016-04-01

    Covalent organic frameworks (COFs) serve as ideal platforms that can selectively adsorb and separate CO2 from gas mixtures. On page 2855, R. Zou, Y. Zhao, and Y. Zeng highlight research progress in this area, compare recent achievements, and present fundamental principles. Different strategies to improve the CO2 capture capability of COFs are elaborated and the capture performance of representative COFs is analyzed. PMID:27075837

  20. MSL Lessons Learned and Knowledge Capture

    NASA Technical Reports Server (NTRS)

    Buxbaum, Karen L.

    2012-01-01

    The Mars Program has recently been informed of the Planetary Protection Subcommittee (PPS) recommendation, which was endorsed by the NAC, concerning Mars Science Lab (MSL) lessons learned and knowledge capture. The Mars Program has not had an opportunity to consider any decisions specific to the PPS recommendation. Some of the activities recommended by the PPS would involve members of the MSL flight team who are focused on cruise, entry descent & landing, and early surface operations; those activities would have to wait. Members of the MSL planetary protection team at JPL are still available to support MSL lessons learned and knowledge capture; some of the specifically recommended activities have already begun. The Mars Program shares the PPS/NAC concerns about loss of potential information & expertise in planetary protection practice.

  1. Thermal neutron capture gamma-rays

    SciTech Connect

    Tuli, J.K.

    1983-01-01

    The energy and intensity of gamma rays as seen in thermal neutron capture are presented. Only those (n,..cap alpha..), E = thermal, reactions for which the residual nucleus mass number is greater than or equal to 45 are included. These correspond to evaluations published in Nuclear Data Sheets. The publication source data are contained in the Evaluated Nuclear Structure Data File (ENSDF). The data presented here do not involve any additional evaluation. Appendix I lists all the residual nuclides for which the data are included here. Appendix II gives a cumulated index to A-chain evaluations including the year of publication. The capture gamma ray data are given in two tables - the Table 1 is the list of all gamma rays seen in (n,..gamma..) reaction given in the order of increasing energy; the Table II lists the gamma rays according to the nuclide.

  2. Interactive animation of 4D performance capture.

    PubMed

    Casas, Dan; Tejera, Margara; Guillemaut, Jean-Yves; Hilton, Adrian

    2013-05-01

    A 4D parametric motion graph representation is presented for interactive animation from actor performance capture in a multiple camera studio. The representation is based on a 4D model database of temporally aligned mesh sequence reconstructions for multiple motions. High-level movement controls such as speed and direction are achieved by blending multiple mesh sequences of related motions. A real-time mesh sequence blending approach is introduced, which combines the realistic deformation of previous nonlinear solutions with efficient online computation. Transitions between different parametric motion spaces are evaluated in real time based on surface shape and motion similarity. Four-dimensional parametric motion graphs allow real-time interactive character animation while preserving the natural dynamics of the captured performance. PMID:23492379

  3. Video Guidance Sensor for automated capture

    NASA Technical Reports Server (NTRS)

    Howard, R. T.; Book, M. L.

    1992-01-01

    The paper describes a video-based sensor, the Video Guidance Sensor, which has been developed for use in automated docking systems or for automated capture with robotic systems. The sensor itself consists of several basic components: IR diode illuminators, a solid-state camera, a frame grabber, and a microprocessor. The target consists of three circular retroreflectors evenly spaced in a line with the middle reflector mounted on a short pole. Each retroreflector has a narrow bandpass optical filter in front of it. From this sensor and target configuration, the positions and attitudes of the target relative to the sensor can be determined. The position information can be differenced to with respect to time in order to obtain the relative positional and angular velocities. That information is sufficient to perform automated docking, berthing, or capture. The paper gives details of the sensor's make-up, including accuracies, noise characteristics, and operating ranges.

  4. Gold nanoparticle capture within protein crystal scaffolds.

    PubMed

    Kowalski, Ann E; Huber, Thaddaus R; Ni, Thomas W; Hartje, Luke F; Appel, Karina L; Yost, Jarad W; Ackerson, Christopher J; Snow, Christopher D

    2016-07-01

    DNA assemblies have been used to organize inorganic nanoparticles into 3D arrays, with emergent properties arising as a result of nanoparticle spacing and geometry. We report here the use of engineered protein crystals as an alternative approach to biologically mediated assembly of inorganic nanoparticles. The protein crystal's 13 nm diameter pores result in an 80% solvent content and display hexahistidine sequences on their interior. The hexahistidine sequence captures Au25(glutathione)∼17 (nitrilotriacetic acid)∼1 nanoclusters throughout a chemically crosslinked crystal via the coordination of Ni(ii) to both the cluster and the protein. Nanoparticle loading was validated by confocal microscopy and elemental analysis. The nanoparticles may be released from the crystal by exposure to EDTA, which chelates the Ni(ii) and breaks the specific protein/nanoparticle interaction. The integrity of the protein crystals after crosslinking and nanoparticle capture was confirmed by single crystal X-ray crystallography. PMID:27264210

  5. Dust grain resonant capture: A statistical study

    NASA Technical Reports Server (NTRS)

    Marzari, F.; Vanzani, V.; Weidenschilling, S. J.

    1993-01-01

    A statistical approach, based on a large number of simultaneous numerical integrations, is adopted to study the capture in external mean motion resonances with the Earth of micron size dust grains perturbed by solar radiation and wind forces. We explore the dependence of the resonant capture phenomenon on the initial eccentricity e(sub 0) and perihelion argument w(sub 0) of the dust particle orbit. The intensity of both the resonant and dissipative (Poynting-Robertson and wind drag) perturbations strongly depends on the eccentricity of the particle while the perihelion argument determines, for low inclination, the mutual geometrical configuration of the particle's orbit with respect to the Earth's orbit. We present results for three j:j+1 commensurabilities (2:3, 4:5 and 6:7) and also for particle sizes s = 15, 30 microns. This study extends our previous work on the long term orbital evolution of single dust particles trapped into resonances with the Earth.

  6. Head-Up Displays and Attention Capture

    NASA Technical Reports Server (NTRS)

    Prinzel, Lawrence J., III; Risser, Matthew

    2004-01-01

    The primary role of head-up displays (HUDs) is to provide primary flight, navigation, and guidance information to the pilot in a forward field-of-view on a head-up transparent screen. Therefore, this theoretically allows for optimal control of an aircraft through the simultaneous scanning of both instrument data and the out-the-window scene. However, despite significant aviation safety benefits afforded by HUDs, a number of accidents have shown that their use does not come without costs. The human factors community has identified significant issues related to the pilot distribution of near and far domain attentional resources because of the compellingness of symbology elements on the HUD; a concern termed, attention or cognitive capture. The paper describes the phenomena of attention capture and presents a selected survey of the literature on the etiology and potential prescriptions.

  7. Layered solid sorbents for carbon dioxide capture

    SciTech Connect

    Li, Bingyun; Jiang, Bingbing; Gray, McMahan L; Fauth, Daniel J; Pennline, Henry W; Richards, George A

    2014-11-18

    A solid sorbent for the capture and the transport of carbon dioxide gas is provided having at least one first layer of a positively charged material that is polyethylenimine or poly(allylamine hydrochloride), that captures at least a portion of the gas, and at least one second layer of a negatively charged material that is polystyrenesulfonate or poly(acryclic acid), that transports the gas, wherein the second layer of material is in juxtaposition to, attached to, or crosslinked with the first layer for forming at least one bilayer, and a solid substrate support having a porous surface, wherein one or more of the bilayers is/are deposited on the surface of and/or within the solid substrate. A method of preparing and using the solid sorbent is provided.

  8. Capture barrier distributions: Some insights and details

    SciTech Connect

    Rowley, N.; Grar, N.; Trotta, M.

    2007-10-15

    The 'experimental barrier distribution' provides a parameter-free representation of experimental heavy-ion capture cross sections that highlights the effects of entrance-channel couplings. Its relation to the s-wave transmission is discussed, and in particular it is shown how the full capture cross section can be generated from an l=0 coupled-channels calculation. Furthermore, it is shown how this transmission can be simply exploited in calculations of quasifission and evaporation-residue cross sections. The system {sup 48}Ca+{sup 154}Sm is studied in detail. A calculation of the compound-nucleus spin distribution reveals a possible energy dependence of barrier weights due to polarization arising from target and projectile quadrupole phonon states; this effect also gives rise to an entrance-channel 'extra-push'.

  9. Nondestructive time-of-capture, location and velocity sensing in intact capture

    NASA Technical Reports Server (NTRS)

    Tsou, Peter

    1994-01-01

    Velocity sensing of hypervelocity particles was a significant field of interest from the 1960s to 1970s. Generically, velocity sensing has been approached by either of two methods: first, detecting direct plasma or light emissions onto a solid surface, or second, performing time-of-flight by film penetration, or by detecting charged particles passing a static electric field. Impact plasma techniques required the destruction of the particles. Multiple-film penetrations were also destructive, especially for small particles. There is a need for an integrated, reliable, and simple location and velocity sensor compatible to our intact capture underdense medium without contributing additional damage to the captured particle. Since cometary dust, like cosmic dust, is essentially randomly distributed, knowing the time of the dust capture and the location of the capture on the collector permits the identification of the specific dust particle captured. Velocity information helps to determine the trajectory of the dust particle. Our discovery of a very suitable acoustic sensor and fruitful experimental results have led to the realization of a flight velocity sensor with intact capture underdense media.

  10. Gold nanoparticle capture within protein crystal scaffolds

    NASA Astrophysics Data System (ADS)

    Kowalski, Ann E.; Huber, Thaddaus R.; Ni, Thomas W.; Hartje, Luke F.; Appel, Karina L.; Yost, Jarad W.; Ackerson, Christopher J.; Snow, Christopher D.

    2016-06-01

    DNA assemblies have been used to organize inorganic nanoparticles into 3D arrays, with emergent properties arising as a result of nanoparticle spacing and geometry. We report here the use of engineered protein crystals as an alternative approach to biologically mediated assembly of inorganic nanoparticles. The protein crystal's 13 nm diameter pores result in an 80% solvent content and display hexahistidine sequences on their interior. The hexahistidine sequence captures Au25(glutathione)~17 (nitrilotriacetic acid)~1 nanoclusters throughout a chemically crosslinked crystal via the coordination of Ni(ii) to both the cluster and the protein. Nanoparticle loading was validated by confocal microscopy and elemental analysis. The nanoparticles may be released from the crystal by exposure to EDTA, which chelates the Ni(ii) and breaks the specific protein/nanoparticle interaction. The integrity of the protein crystals after crosslinking and nanoparticle capture was confirmed by single crystal X-ray crystallography.DNA assemblies have been used to organize inorganic nanoparticles into 3D arrays, with emergent properties arising as a result of nanoparticle spacing and geometry. We report here the use of engineered protein crystals as an alternative approach to biologically mediated assembly of inorganic nanoparticles. The protein crystal's 13 nm diameter pores result in an 80% solvent content and display hexahistidine sequences on their interior. The hexahistidine sequence captures Au25(glutathione)~17 (nitrilotriacetic acid)~1 nanoclusters throughout a chemically crosslinked crystal via the coordination of Ni(ii) to both the cluster and the protein. Nanoparticle loading was validated by confocal microscopy and elemental analysis. The nanoparticles may be released from the crystal by exposure to EDTA, which chelates the Ni(ii) and breaks the specific protein/nanoparticle interaction. The integrity of the protein crystals after crosslinking and nanoparticle capture was

  11. Capture Reactions with Halo Effective Field Theory

    NASA Astrophysics Data System (ADS)

    Higa, R.

    2015-12-01

    Loosely bound nuclei far from the stability region emerge as a quantum phenomenon with many universal properties. The connection between these properties and the underlying symmetries can be best explored with halo/cluster EFT, an effective field theory where the softness of the binding momentum and the hardness of the core(s) form the expansion parameter of a given perturbative approach. In the following I highlight a particular application where these ideas are being tested, namely capture reactions.

  12. Capture cavity II results at FNAL

    SciTech Connect

    Branlard, Julien; Chase, Brian; Cancelo, G.; Carcagno, R.; Edwards, H.; Fliller, R.; Hanna, B.; Harms, Elvan; Hocker, A.; Koeth, T.; Kucera, M.; /Fermilab

    2007-06-01

    As part of the research and development towards the International Linear Collider (ILC), several test facilities have been developed at Fermilab. This paper presents the latest Low Level RF (LLRF) results obtained with Capture Cavity II (CCII) at the ILC Test Accelerator (ILCTA) test facility. The main focus will be on controls and RF operations using the SIMCON based LLRF system developed in DESY [1]. Details about hardware upgrades and future work will be discussed.

  13. Mars Atmospheric Capture and Gas Separation

    NASA Technical Reports Server (NTRS)

    Muscatello, Anthony; Santiago-Maldonado, Edgardo; Gibson, Tracy; Devor, Robert; Captain, James

    2011-01-01

    The Mars atmospheric capture and gas separation project is selecting, developing, and demonstrating techniques to capture and purify Martian atmospheric gases for their utilization for the production of hydrocarbons, oxygen, and water in ISRU systems. Trace gases will be required to be separated from Martian atmospheric gases to provide pure C02 to processing elements. In addition, other Martian gases, such as nitrogen and argon, occur in concentrations high enough to be useful as buffer gas and should be captured as welL To achieve these goals, highly efficient gas separation processes will be required. These gas separation techniques are also required across various areas within the ISRU project to support various consumable production processes. The development of innovative gas separation techniques will evaluate the current state-of-the-art for the gas separation required, with the objective to demonstrate and develop light-weight, low-power methods for gas separation. Gas separation requirements include, but are not limited to the selective separation of: (1) methane and water from un-reacted carbon oxides (C02- CO) and hydrogen typical of a Sabatier-type process, (2) carbon oxides and water from unreacted hydrogen from a Reverse Water-Gas Shift process, (3) carbon oxides from oxygen from a trash/waste processing reaction, and (4) helium from hydrogen or oxygen from a propellant scavenging process. Potential technologies for the separations include freezers, selective membranes, selective solvents, polymeric sorbents, zeolites, and new technologies. This paper and presentation will summarize the results of an extensive literature review and laboratory evaluations of candidate technologies for the capture and separation of C02 and other relevant gases.

  14. Simteche Hydrate CO2 Capture Process

    SciTech Connect

    Nexant and Los Alamos National Laboratory

    2006-09-30

    As a result of an August 4, 2005 project review meeting held at Los Alamos National Laboratory (LANL) to assess the project's technical progress, Nexant/Simteche/LANL project team was asked to meet four targets related to the existing project efforts. The four targets were to be accomplished by the September 30, 2006. These four targets were: (1) The CO{sub 2} hydrate process needs to show, through engineering and sensitivity analysis, that it can achieve 90% CO{sub 2} capture from the treated syngas stream, operating at 1000 psia. The cost should indicate the potential of achieving the Sequestration Program's cost target of less than 10% increase in the cost of electricity (COE) of the non-CO{sub 2} removal IGCC plant or demonstrate a significant cost reduction from the Selexol process cost developed in the Phase II engineering analysis. (2) The ability to meet the 20% cost share requirement for research level efforts. (3) LANL identifies through equilibrium and bench scale testing a once-through 90% CO{sub 2} capture promoter that supports the potential to achieve the Sequestration Program's cost target. Nexant is to perform an engineering analysis case to verify any economic benefits, as needed; no ETM validation is required, however, for this promoter for FY06. (4) The CO{sub 2} hydrate once-through process is to be validated at 1000 psia with the ETM at a CO{sub 2} capture rate of 60% without H{sub 2}S. The performance of 68% rate of capture is based on a batch, equilibrium data with H{sub 2}S. Validation of the test results is required through multiple runs and engineering calculations. Operational issues will be solved that will specifically effect the validation of the technology. Nexant was given the primary responsibility for Target No.1, while Simteche was mainly responsible for Target No.2; with LANL having the responsibility of Targets No.3 and No.4.

  15. Does Involuntary Attentional Capture Curtail Stimulus Processing

    NASA Technical Reports Server (NTRS)

    Remington, Roger W.; McLean, John P.; Folk, Charles L.; Null, Cynthia H. (Technical Monitor)

    1996-01-01

    Under certain conditions uninformative visual cues at non-target locations increase target RTs. The typical explanation is that visual attention has been involuntarily summoned to the cued location and is unavailable when needed at the target location. Here we present evidence that capture has not just oriented attention away from the target location, but has lead to the processing of stimuli at the location of the uninformative cue.

  16. Electron capture decay in Jovian planets

    NASA Astrophysics Data System (ADS)

    Zito, R. R.; Schiferl, D.

    1987-12-01

    Following the commonly acknowledged fact that the decay of K-40 substantially contributes to the heating of planetary interiors, an examination is made of the possibility that interior heat in the Jovian planets and stars, where interior pressures may exceed 45 Mbar, may be generated by the pressure-accelerated electron capture decay of a variety of isotopes. The isotopes considered encompass K-40, V-50, Te-123, La-138, Al-26, and Cl-36.

  17. Double electron capture searches in 74Se

    NASA Astrophysics Data System (ADS)

    Lehnert, B.; Wester, T.; Degering, D.; Sommer, D.; Wagner, L.; Zuber, K.

    2016-08-01

    A search for various double electron capture modes of 74Se has been performed using an ultralow background Ge-detector in the Felsenkeller laboratory, Germany. Especially for the potentially resonant transition into the 1204.2 keV excited state of 74Ge a lower half-life limit of 0.70× {10}19 yr (90% credibility) has been obtained. Serious concerns are raised about the validity of obtained 74Se limits in some recent publications.

  18. Impact Detections of Temporarily Captured Natural Satellites

    NASA Astrophysics Data System (ADS)

    Clark, David L.; Spurný, Pavel; Wiegert, Paul; Brown, Peter; Borovička, Jiří; Tagliaferri, Ed; Shrbený, Lukáš

    2016-06-01

    Temporarily captured orbiters (TCOs) are near-Earth objects (NEOs) that make a few orbits of Earth before returning to heliocentric orbits. Only one TCO has been observed to date, 2006 RH120, captured by Earth for one year before escaping. Detailed modeling predicts that capture should occur from the NEO population predominantly through the Sun–Earth L1 and L2 points, with 1% of TCOs impacting Earth and approximately 0.1% of meteoroids being TCOs. Although thousands of meteoroid orbits have been measured, none until now have conclusively exhibited TCO behavior, largely due to difficulties in measuring initial meteoroid speed with sufficient precision. We report on a precise meteor observation of 2014 January 13 with a new generation of all-sky fireball digital camera systems operated in the Czech Republic as part of the European Fireball Network, providing the lowest natural object entry speed observed in decades-long monitoring by networks worldwide. Modeling atmospheric deceleration and fragmentation yields an initial mass of ∼5 kg and diameter of 15 cm, with a maximum Earth-relative velocity just over 11.0 km s‑1. Spectral observations prove its natural origin. Back integration across observational uncertainties yields a 92%–98% probability of TCO behavior, with close lunar dynamical interaction. The capture duration varies across observational uncertainties from 48 days to 5+ years. We also report on two low-speed impacts recorded by US Government sensors, and we examine Prairie Network event PN39078 from 1965 with an extremely low entry speed of 10.9 km s‑1. In these cases uncertainties in measurement and origin make TCO designation uncertain.

  19. Data Capture Technique for High Speed Signaling

    DOEpatents

    Barrett, Wayne Melvin; Chen, Dong; Coteus, Paul William; Gara, Alan Gene; Jackson, Rory; Kopcsay, Gerard Vincent; Nathanson, Ben Jesse; Vranas, Paylos Michael; Takken, Todd E.

    2008-08-26

    A data capture technique for high speed signaling to allow for optimal sampling of an asynchronous data stream. This technique allows for extremely high data rates and does not require that a clock be sent with the data as is done in source synchronous systems. The present invention also provides a hardware mechanism for automatically adjusting transmission delays for optimal two-bit simultaneous bi-directional (SiBiDi) signaling.

  20. Binaural processing by the gecko auditory periphery

    PubMed Central

    Christensen-Dalsgaard, Jakob; Tang, Yezhong

    2011-01-01

    Lizards have highly directional ears, owing to strong acoustical coupling of the eardrums and almost perfect sound transmission from the contralateral ear. To investigate the neural processing of this remarkable tympanic directionality, we combined biophysical measurements of eardrum motion in the Tokay gecko with neurophysiological recordings from the auditory nerve. Laser vibrometry shows that their ear is a two-input system with approximately unity interaural transmission gain at the peak frequency (∼1.6 kHz). Median interaural delays are 260 μs, almost three times larger than predicted from gecko head size, suggesting interaural transmission may be boosted by resonances in the large, open mouth cavity (Vossen et al. 2010). Auditory nerve recordings are sensitive to both interaural time differences (ITD) and interaural level differences (ILD), reflecting the acoustical interactions of direct and indirect sound components at the eardrum. Best ITD and click delays match interaural transmission delays, with a range of 200–500 μs. Inserting a mold in the mouth cavity blocks ITD and ILD sensitivity. Thus the neural response accurately reflects tympanic directionality, and most neurons in the auditory pathway should be directional. PMID:21325679

  1. Metazen – metadata capture for metagenomes

    DOE PAGESBeta

    Bischof, Jared; Harrison, Travis; Paczian, Tobias; Glass, Elizabeth; Wilke, Andreas; Meyer, Folker

    2014-12-08

    Background: As the impact and prevalence of large-scale metagenomic surveys grow, so does the acute need for more complete and standards compliant metadata. Metadata (data describing data) provides an essential complement to experimental data, helping to answer questions about its source, mode of collection, and reliability. Metadata collection and interpretation have become vital to the genomics and metagenomics communities, but considerable challenges remain, including exchange, curation, and distribution. Currently, tools are available for capturing basic field metadata during sampling, and for storing, updating and viewing it. These tools are not specifically designed for metagenomic surveys; in particular, they lack themore » appropriate metadata collection templates, a centralized storage repository, and a unique ID linking system that can be used to easily port complete and compatible metagenomic metadata into widely used assembly and sequence analysis tools. Results: Metazen was developed as a comprehensive framework designed to enable metadata capture for metagenomic sequencing projects. Specifically, Metazen provides a rapid, easy-to-use portal to encourage early deposition of project and sample metadata. Conclusion: Metazen is an interactive tool that aids users in recording their metadata in a complete and valid format. A defined set of mandatory fields captures vital information, while the option to add fields provides flexibility.« less

  2. Metazen – metadata capture for metagenomes

    SciTech Connect

    Bischof, Jared; Harrison, Travis; Paczian, Tobias; Glass, Elizabeth; Wilke, Andreas; Meyer, Folker

    2014-12-08

    Background: As the impact and prevalence of large-scale metagenomic surveys grow, so does the acute need for more complete and standards compliant metadata. Metadata (data describing data) provides an essential complement to experimental data, helping to answer questions about its source, mode of collection, and reliability. Metadata collection and interpretation have become vital to the genomics and metagenomics communities, but considerable challenges remain, including exchange, curation, and distribution. Currently, tools are available for capturing basic field metadata during sampling, and for storing, updating and viewing it. These tools are not specifically designed for metagenomic surveys; in particular, they lack the appropriate metadata collection templates, a centralized storage repository, and a unique ID linking system that can be used to easily port complete and compatible metagenomic metadata into widely used assembly and sequence analysis tools. Results: Metazen was developed as a comprehensive framework designed to enable metadata capture for metagenomic sequencing projects. Specifically, Metazen provides a rapid, easy-to-use portal to encourage early deposition of project and sample metadata. Conclusion: Metazen is an interactive tool that aids users in recording their metadata in a complete and valid format. A defined set of mandatory fields captures vital information, while the option to add fields provides flexibility.

  3. Laser-induced electron capture mass spectrometry

    PubMed

    Wang; Giese

    2000-02-15

    Two techniques are reported for detection of electrophorederivatized compounds by laser-induced electron capture time-of-flight mass spectrometry (LI-EC-TOF-MS). In both cases, a nitrogen laser is used to induce the electron capture. The analyte is deposited in a matrix consisting of a compound with a low ionization potential such as benzo[ghi]perylene in the first technique, where the electron for electron capture apparently comes from this matrix. In the second technique, the analyte is deposited on a silver surface in the absence of matrix. It seems that "monoenergetic" ions instantly desorb from the target surface in the latter case, since the peak width in the continuous extraction mode essentially matches the pulse width of the laser (4 ns). Ten picomoles of 3-O-(pentafluorobenzyl)-alpha-estradiol were detected at a S/N > or = 50, where the spot size of the laser was approximately 0.25% of the sample spot. It is attractive that simple conditions can enable sensitive detection of electrophores on routine TOF-MS equipment. The technique can be anticipated to broaden the range of analytes in both polarity and size that can be detected by EC-MS relative to the range for GC/EC-MS. PMID:10701262

  4. Mercury capture in bench-scale absorbers

    SciTech Connect

    Livengood, C.D.; Huang, H.S.; Mendelsohn, M.H.; Wu, J.M.

    1994-08-01

    This paper gives,a brief overview of research being conducted at Argonne National Laboratory on the capture of mercury by both dry sorbents and wet scrubbers. The emphasis in the research is on development of a better understanding of the key factors that control the capture of mercury. Future work is expected to utilize that information for the development of new or modified process concepts featuring enhanced mercury capture capabilities. The results and conclusions to date from the Argonne -research on dry sorbents can be summarized as follows: lime hydrates, either regular or high-surface-area, are `not effective in removing mercury; mercury removals are enhanced by the addition of activated carbon; mercury removals with activated carbon decrease with increasing temperature, larger particle size, and decreasing mercury concentration in the gas; and chemical pretreatment (e.g., with sulfur or (CaCl{sub 2}) can greatly increase the removal capacity of activated carbon. Preliminary results from the wet scrubbing research include: no removal of elemental mercury is obtained under normal scrubber operating conditions; mercury removal is improved by the addition of packing or production of smaller gas bubbles to increase the gas-liquid contact area; polysulfide solutions do not appear promising for enhancing mercury removal in typical FGC systems; stainless steel packing appears to have beneficial properties for mercury removal and should be investigated further; and other chemical additives may offer greatly enhanced removals.

  5. Neutron-Resonance Capture Analysis of Materials

    SciTech Connect

    Postma, H.; Bode, P.; Blaauw, M.; Corvi, F.

    1999-11-14

    Epithermal neutron activation analysis is a well-established approach to improve the sensitivity for certain elements by suppressing the activation of interfering elements. If epithermal neutrons of a given energy could be selected, the signal-to-noise ratio might be further improved by taking advantage of resonance capture. This reaction occurs mainly by intermediate and heavy nuclei. Moreover, most of these reactions take place with epithermal or fast neutrons. Intense epithermal neutrons are available as ''white'' beams at accelerator-driven neutron sources. Neutron resonance capture offers interesting analytical opportunities. Low-Z elements have little capture of epithermal neutrons and are thus virtually absent in the time-of-flight spectrum. Relatively large objects can be placed in the neutron beam and analyzed nondestructively. The induced radioactivity is relatively low. If an element has several stable isotopes, each of these isotopes can be recognized by its specific resonances. This would allow for multitracer studies with several isotopically labeled compounds. Different from mass spectrometry, the sample remains intact and can be used for further studies after analysis. Applications may be in the field of archaeology, metallurgy, and certification of reference materials.

  6. Optimal ballistically captured Earth-Moon transfers

    NASA Astrophysics Data System (ADS)

    Ricord Griesemer, Paul; Ocampo, Cesar; Cooley, D. S.

    2012-07-01

    The optimality of a low-energy Earth-Moon transfer terminating in ballistic capture is examined for the first time using primer vector theory. An optimal control problem is formed with the following free variables: the location, time, and magnitude of the transfer insertion burn, and the transfer time. A constraint is placed on the initial state of the spacecraft to bind it to a given initial orbit around a first body, and on the final state of the spacecraft to limit its Keplerian energy with respect to a second body. Optimal transfers in the system are shown to meet certain conditions placed on the primer vector and its time derivative. A two point boundary value problem containing these necessary conditions is created for use in targeting optimal transfers. The two point boundary value problem is then applied to the ballistic lunar capture problem, and an optimal trajectory is shown. Additionally, the problem is then modified to fix the time of transfer, allowing for optimal multi-impulse transfers. The tradeoff between transfer time and fuel cost is shown for Earth-Moon ballistic lunar capture transfers.

  7. Material capture by double lunar gravity assist

    NASA Technical Reports Server (NTRS)

    Ross, D. J.

    1980-01-01

    The equations yielding the performance of a single lunar flyby in removing incoming hyperbolic excess velocity to capture payloads on interplanetary trajectories are briefly derived. The impossibility of using a single lunar flyby to capture a body entering the earth-moon system with a hyperbolic velocity in excess of about 1.9 km/s is discussed, and a method of using a double flyby of the moon to significantly improve this performance is developed. The equations for achieving a double lunar flyby are derived by solving the orbital equations and Lambert's problem both for the incoming trajectory in the plane of the moon's orbit and for arbitrary declination. For the in-plane case it is shown that the maximum removable hyperbolic excess velocity is 2.2687 km/s. For the inclined case, it is shown that the use of a double lunar flyby allows capture for declinations in excess of 54 degrees, and that for declinations less than 38 degrees the double lunar flyby offers better performance than the single lunar flyby.

  8. Review of the fundamentals of the neutron-capture reaction

    SciTech Connect

    Chrien, R. E.

    1982-01-01

    Fifty years of research into the nature of the radiative capture reaction mechanisms is briefly summarized. A variety of such mechanisms is exploited to explain neutron capture over nine decades of neutron energy.

  9. Neutron Capture Experiments on Unstable Nuclei

    SciTech Connect

    Schwantes, Jon M.; Sudowe, Ralf; Folden, Charles M., III; Nitsche, Heino; Hoffman, Darleane C.

    2005-01-15

    The overall objective of this project is the measurement of neutron capture cross sections of importance to stewardship science and astrophysical modeling of nucleosynthesis, while at the same time helping to train the next generation of scientists with expertise relevant to U.S. national nuclear security missions and to stewardship science. A primary objective of this project is to study neutron capture cross sections for various stable and unstable isotopes that will contribute to the Science Based Stockpile Stewardship (SBSS) program by providing improved data for modeling and interpretation of nuclear device performance. Much of the information obtained will also be important in astrophysical modeling of nucleosynthesis. Measurements of these neutron capture cross sections are being conducted in collaboration with researchers at the Los Alamos Neutron Science Center (LANSCE) facility using the unique Detector for Advanced Neutron Capture Experiments (DANCE). In our early discussions with the DANCE group, decisions were made on the first cross sections to be measured and how our expertise in target preparation, radiochemical separations chemistry, and data analysis could best be applied. The initial emphasis of the project was on preparing suitable targets of both natural and separated stable europium isotopes in preparation for the ultimate goal of preparing a sufficiently large target of radioactive 155Eu (t1/2 = 4.7 years) and other radioactive and stable species for neutron cross-section measurements at DANCE. Our Annual Report, ''Neutron Capture Experiments on Unstable Nuclei'' by J. M. Schwantes, R. Sudowe, C. M. Folden III, H. Nitsche, and D. C. Hoffman, submitted to NNSA in December 2003, gives details about the initial considerations and scope of the project. During the current reporting period, electroplated targets of natural Eu together with valuable, stable, and isotopically pure 151Eu and 153Eu, and isotopically separated 154Sm were measured for

  10. Tanpopo: Astrobiology Exposure and Micrometeoroid Capture Experiments

    NASA Astrophysics Data System (ADS)

    Yamagishi, Akihiko; Yano, Hajime; Yamashita, Masamichi; Hashimoto, Hirofumi; Kobayashi, Kensei; Kawai, Hideyuki; Mita, Hajime; Yokobori, Shin-ichi; Tabata, Makoto; Yabuta, Hikaru

    2012-07-01

    There is a long history of the microbe-collection experiments at high altitude (1). Microbes have been collected using balloons, aircraft and meteorological rockets. Spore forming fungi and Bacilli, and Micrococci have been isolated in these experiments (1). It is not clear how high do microbes go up. If the microbes might have been present even at higher altitudes, the fact would endorse the possibility of interplanetary migration of life. Tanpopo, dandelion, is the name of a grass whose seeds with floss are spread by the wind. We propose the analyses of interplanetary migration of microbes, organic compounds and meteoroids on Japan Experimental Module (JEM) of the International Space Station (ISS) (2). Ultra low-density aerogel will be used to capture micrometeoroid and debris. Particles captured by aerogel will be used for several analyses after the initial inspection of the gel and tracks. Careful analysis of the tracks in the aerogel will provide the size and velocity dependence of debris flux. The particles will be analyzed for mineralogical, organic and microbiological characteristics. Aerogels are ready for production in Japan. Aerogels and trays are space proven. All the analytical techniques are ready. In this presentation, we will present the recent results related to the microbiological analyses. The results suggested that the bleaching speeds and the spectra of fluorescence are different between different origins of the fluorescence: whether it is emitted from microbe or not. It is also shown that PCR analysis of the microbe can be used to determine the species. References 1)Yang, Y., Yokobori, S. and Yamagishi, A.: Assessing panspermia hypothesis by microorganisms collected from the high altitude atmosphere. Biol. Sci. Space, 23 (2009), pp. 151-163. 2) Yamagishi, A., H. Yano, K. Kobayashi, K. Kobayashi, S. Yokobori, M. Tabata, H. Kawai, M. Yamashita, H. Hashimoto, H. Naraoka, & H. Mita (2008) TANPOPO: astrobiology exposure and micrometeoroid capture

  11. Tanpopo: Astrobiology exposure and micrometeoroid capture experiments

    NASA Astrophysics Data System (ADS)

    Yamagishi, Akihiko; Yano, Hajime; Okudaira, Kyoko; Kobayashi, Kensei; Yokobori, Shin-Ichi; Kawai, Hideyuki; Yamashita, Masamichi; Hashimoto, Hirofumi; Yabuta, Hikaru

    There is a long history of the microbe-collection experiments at high altitude (1). Microbes have been collected using balloons, aircraft and meteorological rockets. Spore forming fungi and Bacilli, and Micrococci have been isolated in these experiments (1). It is not clear how high do microbes go up. If the microbes might have been present even at higher altitudes, the fact would endorse the possibility of interplanetary migration of life. Tanpopo, dandelion, is the name of a grass whose seeds with floss are spread by the wind. We propose the analyses of interplanetary migration of microbes, organic compounds and meteoroids on Japan Experimental Module (JEM) of the International Space Station (ISS) (2). Ultra low-density aerogel will be used to capture micrometeoroid and debris. Particles captured by aerogel will be used for several analyses after the initial inspection of the gel and tracks. Careful analysis of the tracks in the aerogel will provide the size and velocity dependence of debris flux. The particles will be analyzed for mineralogical, organic and microbiological characteristics. Aerogels are ready for production in Japan. Aerogels and trays are space proven. All the analytical techniques are ready. In this presentation, we will present the recent results related to the microbiological analyses. The results suggested that the bleaching speeds and the spectra of fluorescence are different between different origins of the fluorescence: whether it is emitted from microbe or not. It is also shown that PCR analysis of the microbe can be used to determine the species. References 1)Yang, Y., Yokobori, S. and Yamagishi, A.: Assessing panspermia hypothesis by microorganisms collected from the high altitude atmosphere. Biol. Sci. Space, 23 (2009), pp. 151-163. 2) Yamagishi, A., H. Yano, K. Kobayashi, K. Kobayashi, S. Yokobori, M. Tabata, H. Kawai, M. Yamashita, H. Hashimoto, H. Naraoka, H. Mita (2008) TANPOPO: astrobi-ology exposure and micrometeoroid capture

  12. Comparison of Ring-Buffer-Based Packet Capture Solutions

    SciTech Connect

    Barker, Steven Andrew

    2015-10-01

    Traditional packet-capture solutions using commodity hardware incur a large amount of overhead as packets are copied multiple times by the operating system. This overhead slows sensor systems to a point where they are unable to keep up with high bandwidth traffic, resulting in dropped packets. Incomplete packet capture files hinder network monitoring and incident response efforts. While costly commercial hardware exists to capture high bandwidth traffic, several software-based approaches exist to improve packet capture performance using commodity hardware.

  13. Capturing Depolarization Information in GPS Reflections

    NASA Technical Reports Server (NTRS)

    Kelly, Kenneth C.

    2000-01-01

    The state of the surface of the ocean has a prominent effect on the depolarization of the circularly polarized emissions of the GPS satellites. The system designers election to capture the important information carries with it the need to implement the data extraction in a cost efficient manner. Antenna components, and associated networks for deriving depolarization information are described. For typical sea states the polarization characteristics of the reflected GPS signal vary rapidly with time so various methods for recording the changes are discussed.

  14. Does tidal capture produce cataclysmic variables?

    NASA Technical Reports Server (NTRS)

    Bailyn, Charles D.; Grindlay, Jonathan E.; Garcia, Michael R.

    1990-01-01

    It is shown that earlier estimates of the number of cataclysmic variables (CVs) to be expected from tidal capture in globular clusters may have been considerably too high, since many such binaries will result in unstable mass transfer, and thus not become CVs after all. In particular, CVs with white dwarf masses less than or obout 1.0 solar mass will be supressed. Such unstable mass transfer events may produce some of the cluster mass loss required to stabilize the cluster core. The smaller number of stable CVs predicted may suggest a reconsideration of the nature of some of the low-luminosity cluster X-ray sources.

  15. Capturing near-Earth asteroids around Earth

    NASA Astrophysics Data System (ADS)

    Hasnain, Zaki; Lamb, Christopher A.; Ross, Shane D.

    2012-12-01

    The list of detected near-Earth asteroids (NEAs) is constantly growing. NEAs are likely targets for resources to support space industrialization, as they may be the least expensive source of certain needed raw materials. The limited supply of precious metals and semiconducting elements on Earth may be supplemented or even replaced by the reserves floating in the form of asteroids around the solar system. Precious metals make up a significant fraction NEAs by mass, and even one metallic asteroid of ˜1km size and fair enrichment in platinum-group metals would contain twice the tonnage of such metals already harvested on Earth. There are ˜1000 NEAs with a diameter of greater than 1 km. Capturing these asteroids around the Earth would expand the mining industry into an entirely new dimension. Having such resources within easy reach in Earth's orbit could provide an off-world environmentally friendly remedy for impending terrestrial shortages, especially given the need for raw materials in developing nations. In this paper, we develop and implement a conceptually simple algorithm to determine trajectory characteristics necessary to move NEAs into capture orbits around the Earth. Altered trajectories of asteroids are calculated using an ephemeris model. Only asteroids of eccentricity less than 0.1 have been studied and the model is restricted to the ecliptic plane for simplicity. We constrain the time of retrieval to be 10 years or less, based on considerations of the time to return on investment. For the heliocentric phase, constant acceleration is assumed. The acceleration required for transporting these asteroids from their undisturbed orbits to the sphere of influence of the Earth is the primary output, along with the impulse or acceleration necessary to effect capture to a bound orbit once the Earth's sphere of influence is reached. The initial guess for the constant acceleration is provided by a new estimation method, similar in spirit to Edelbaum's. Based on the

  16. Three-Nucleon Electroweak Capture Reactions

    SciTech Connect

    L.E. Marcucci; M. Viviani; A. Kievsky; S. Rosati; R. Schiavilla

    2002-10-01

    Recent advances in the study of the p-d radiative and mu-3he weak capture processes are presented and discussed. The three-nucleon bound and scattering states are obtained using the correlated-hyperspherical-harmonics method, with realistic Hamiltonians consisting of the Argonne v14 or Argonne v18 two-nucleon and Tucson-Melbourne or Urbana IX three-nucleon interactions. The electromagnetic and weak transition operators include one- and two-body contributions. The theoretical accuracy achieved in these calculations allows for interesting comparisons with experimental data.

  17. Microspine Gripping Mechanism for Asteroid Capture

    NASA Technical Reports Server (NTRS)

    Merriam, Ezekiel G.; Berg, Andrew B.; Willig, Andrew; Parness, Aaron; Frey, Tim; Howell, Larry L.

    2016-01-01

    This paper details the development and early testing of a compliant suspension for a microspine gripper device for asteroid capture or micro-gravity percussive drilling. The microspine gripper architecture is reviewed, and a proposed microspine suspension design is presented and discussed. Prototyping methods are discussed, as well as testing methods and results. A path forward is identified from the results of the testing completed thus far. Key findings include: the microspine concept has been established as a valid architecture and the compliant suspension exhibits the desired stiffness characteristics for good gripping behavior. These developments will aid in developing the capability to grasp irregularly shaped boulders in micro-gravity.

  18. Wyoming Carbon Capture and Storage Institute

    SciTech Connect

    Nealon, Teresa

    2014-06-30

    This report outlines the accomplishments of the Wyoming Carbon Capture and Storage (CCS) Technology Institute (WCTI), including creating a website and online course catalog, sponsoring technology transfer workshops, reaching out to interested parties via news briefs and engaging in marketing activities, i.e., advertising and participating in tradeshows. We conclude that the success of WCTI was hampered by the lack of a market. Because there were no supporting financial incentives to store carbon, the private sector had no reason to incur the extra expense of training their staff to implement carbon storage. ii

  19. Neutron Capture Cross Section of 239Pu

    NASA Astrophysics Data System (ADS)

    Mosby, S.; Arnold, C.; Bredeweg, T. A.; Couture, A.; Jandel, M.; O'Donnell, J. M.; Rusev, G.; Ullmann, J. L.; Chyzh, A.; Henderson, R.; Kwan, E.; Wu, C. Y.

    2014-09-01

    The 239Pu(n,γ) cross section has been measured over the energy range 10 eV - 10 keV using the Detector for Advanced Neutron Capture Experiments (DANCE) as part of a campaign to produce precision (n,γ) measurements on 239Pu in the keV region. Fission coincidences were measured with a PPAC and used to characterize the prompt fission γ-ray spectrum in this region. The resulting spectra will be used to better characterize the fission component of another experiment with a thicker target to extend the (n,γ) cross section measurement well into the keV region.

  20. Recent advances in neutron capture therapy (NCT)

    SciTech Connect

    Fairchild, R.G.

    1985-01-01

    The application of the /sup 10/B(n,..cap alpha..)/sup 7/Li reaction to cancer radiotherapy (Neutron Capture therapy, or NCT) has intrigued investigators since the discovery of the neutron. This paper briefly summarizes data describing recently developed boronated compounds with evident tumor specificity and extended biological half-lives. The implication of these compounds to NCT is evaluated in terms of Therapeutic Gain (TG). The optimization of NCT using band-pass filtered beams is described, again in terms of TG, and irradiation times with these less intense beams are estimated. 24 refs., 3 figs., 3 tabs.

  1. Capture of carbon dioxide by hybrid sorption

    SciTech Connect

    Srinivasachar, Srivats

    2014-09-23

    A composition, process and system for capturing carbon dioxide from a combustion gas stream. The composition has a particulate porous support medium that has a high volume of pores, an alkaline component distributed within the pores and on the surface of the support medium, and water adsorbed on the alkaline component, wherein the proportion of water in the composition is between about 5% and about 35% by weight of the composition. The process and system contemplates contacting the sorbent and the flowing gas stream together at a temperature and for a time such that some water remains adsorbed in the alkaline component when the contact of the sorbent with the flowing gas ceases.

  2. Electron capture on iron group nuclei

    SciTech Connect

    Dean, D.J.; Chatterjee, L.; Strayer, M.R.; Dean, D.J.; Chatterjee, L.; Langanke, K.; Chatterjee, L.; Radha, P.B.

    1998-07-01

    We present Gamow-Teller strength distributions from shell model Monte Carlo studies of fp-shell nuclei that may play an important role in the precollapse evolution of supernovas. We then use these strength distributions to calculate the electron-capture cross sections and rates in the zero-momentum transfer limit. We also discuss the thermal behavior of the cross sections. We find large differences in these cross sections and rates when compared to the naive single-particle estimates. These differences need to be taken into account for improved modeling of the early stages of type-II supernova evolution. thinsp {copyright} {ital 1998} {ital The American Physical Society}

  3. Eddington capture sphere around luminous relativistic stars

    NASA Astrophysics Data System (ADS)

    Wielgus, Maciek

    2016-02-01

    We discuss the interplay of gravity and radiation in a static, spherically symmetric spacetime. Because of the spacetime curvature, balance between radiation pressure from spherical star and effective force of gravity may be established in a particular distance from the star surface, on so-called Eddington capture sphere. This is in contrast with the Newtonian scenario, for which Eddington luminosity of the radiation assures gravity-radiation balance at any radius. We explore properties of this relativistic equilibrium and the dynamics of test particles under radiation influence in the strong gravity regime.

  4. Materials design for electrocatalytic carbon capture

    NASA Astrophysics Data System (ADS)

    Tan, Xin; Tahini, Hassan A.; Smith, Sean C.

    2016-05-01

    We discuss our philosophy for implementation of the Materials Genome Initiative through an integrated materials design strategy, exemplified here in the context of electrocatalytic capture and separation of CO2 gas. We identify for a group of 1:1 X-N graphene analogue materials that electro-responsive switchable CO2 binding behavior correlates with a change in the preferred binding site from N to the adjacent X atom as negative charge is introduced into the system. A reconsideration of conductive N-doped graphene yields the discovery that the N-dopant is able to induce electrocatalytic binding of multiple CO2 molecules at the adjacent carbon sites.

  5. Laser capture microdissection of kidney tissue.

    PubMed

    Woroniecki, Robert P; Bottinger, Erwin P

    2009-01-01

    Kidney tissue laser capture microdissection (LCM) is of great clinical relevance since genome wide studies on total kidney messenger RNA (mRNA) potentially miss important factors involved in the pathogenesis of the disease in glomeruli and tubules. This technique is readily applicable to study mRNA from isolated glomeruli and tubules of human kidney biopsy material. In this chapter we present a "cook-book" practical approach of utilizing LCM in combination with RNA isolation technique in downstream applications in nephrology. PMID:19148600

  6. Software support environment design knowledge capture

    NASA Technical Reports Server (NTRS)

    Dollman, Tom

    1990-01-01

    The objective of this task is to assess the potential for using the software support environment (SSE) workstations and associated software for design knowledge capture (DKC) tasks. This assessment will include the identification of required capabilities for DKC and hardware/software modifications needed to support DKC. Several approaches to achieving this objective are discussed and interim results are provided: (1) research into the problem of knowledge engineering in a traditional computer-aided software engineering (CASE) environment, like the SSE; (2) research into the problem of applying SSE CASE tools to develop knowledge based systems; and (3) direct utilization of SSE workstations to support a DKC activity.

  7. Hybridization Capture Using Short PCR Products Enriches Small Genomes by Capturing Flanking Sequences (CapFlank)

    PubMed Central

    Tsangaras, Kyriakos; Wales, Nathan; Sicheritz-Pontén, Thomas; Rasmussen, Simon; Michaux, Johan; Ishida, Yasuko; Morand, Serge; Kampmann, Marie-Louise; Gilbert, M. Thomas P.; Greenwood, Alex D.

    2014-01-01

    Solution hybridization capture methods utilize biotinylated oligonucleotides as baits to enrich homologous sequences from next generation sequencing (NGS) libraries. Coupled with NGS, the method generates kilo to gigabases of high confidence consensus targeted sequence. However, in many experiments, a non-negligible fraction of the resulting sequence reads are not homologous to the bait. We demonstrate that during capture, the bait-hybridized library molecules add additional flanking library sequences iteratively, such that baits limited to targeting relatively short regions (e.g. few hundred nucleotides) can result in enrichment across entire mitochondrial and bacterial genomes. Our findings suggest that some of the off-target sequences derived in capture experiments are non-randomly enriched, and that CapFlank will facilitate targeted enrichment of large contiguous sequences with minimal prior target sequence information. PMID:25275614

  8. Lecture Capture in Engineering Classes: Bridging Gaps and Enhancing Learning

    ERIC Educational Resources Information Center

    Al Nashash, Hasan; Gunn, Cindy

    2013-01-01

    This paper explores the use of lecture capture in Engineering classes to provide students with the opportunity to enhance their understanding of the course content. Students were asked to provide feedback on what they perceive the benefits and the drawbacks of lecture capture to be. The results show that the students consider lecture capture an…

  9. Capture of neon atoms by sup 4 He clusters

    SciTech Connect

    Scheidemann, A.; Toennies, J.P. ); Northby, J.A. )

    1990-04-16

    Neon atoms are captured by helium clusters in a crossed-beam experiment. The capture process depends strongly on the cluster beam source conditions. We identify a sharply defined region corresponding to expansions passing near the critical point for which the capture probability is anomalously large.

  10. Disagreement between capture probabilities extracted from capture and quasi-elastic backscattering excitation functions

    NASA Astrophysics Data System (ADS)

    Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.; Gomes, R. P. S.

    2014-12-01

    Experimental quasi-elastic backscattering and capture (fusion) excitation functions are usually used to extract the s -wave capture probabilities for the heavy-ion reactions. We investigated the 16O + 120Sn , 144Sm , 208Pb systems at energies near and below the corresponding interaction barriers and concluded that the probabilities extracted from quasi-elastic data are much larger than the ones extracted from fusion excitation functions at sub and deep-sub barrier energies. This seems to be a reasonable explanation for the known disagreement observed in the literature for the nuclear potential diffuseness derived from both methods.

  11. Laser capture microdissection for gene expression analysis.

    PubMed

    Bidarimath, Mallikarjun; Edwards, Andrew K; Tayade, Chandrakant

    2015-01-01

    Laser capture microdissection (LCM) is an excellent and perhaps the only platform to isolate homogeneous cell populations from specific microscopic regions of heterogeneous tissue section, under direct microscopic visualization. The basic operations of the LCM system are based on (a) microscopic visualization of phenotypically identified cells of interest, (b) selective adherence of cells to a melting thermolabile film/membrane using a low-energy infrared laser (IR system) or photovolatization of cells within a selected region (UV system), (c) capturing or catapulting of structurally intact cells from a stained tissue section. RNA/DNA or protein can be extracted from the cell or tissue fragments for downstream applications to quantitatively study gene expression. This method can be applied to many downstream analyses including but not limited to quantitative real-time polymerase chain reaction (PCR), microarray, DNA genotyping, RNA transcript profiling, generation of cDNA library, mass spectrometry analysis, and proteomic discovery.The application of LCM is described here to specifically and reliably obtain a homogeneous cell population in order to extract RNA to study microRNA expression by quantitative real-time PCR. PMID:25308266

  12. Applying Content Management to Automated Provenance Capture

    SciTech Connect

    Schuchardt, Karen L.; Gibson, Tara D.; Stephan, Eric G.; Chin, George

    2008-04-10

    Workflows and data pipelines are becoming increasingly valuable in both computational and experimen-tal sciences. These automated systems are capable of generating significantly more data within the same amount of time than their manual counterparts. Automatically capturing and recording data prove-nance and annotation as part of these workflows is critical for data management, verification, and dis-semination. Our goal in addressing the provenance challenge was to develop and end-to-end system that demonstrates real-time capture, persistent content management, and ad-hoc searches of both provenance and metadata using open source software and standard protocols. We describe our prototype, which extends the Kepler workflow tools for the execution environment, the Scientific Annotation Middleware (SAM) content management software for data services, and an existing HTTP-based query protocol. Our implementation offers several unique capabilities, and through the use of standards, is able to pro-vide access to the provenance record to a variety of commonly available client tools.

  13. Capturing CO2 via reactions in nanopores.

    SciTech Connect

    Leung, Kevin; Nenoff, Tina Maria; Criscenti, Louise Jacqueline; Tang, Z; Dong, J. H.

    2008-10-01

    This one-year exploratory LDRD aims to provide fundamental understanding of the mechanism of CO2 scrubbing platforms that will reduce green house gas emission and mitigate the effect of climate change. The project builds on the team member's expertise developed in previous LDRD projects to study the capture or preferential retention of CO2 in nanoporous membranes and on metal oxide surfaces. We apply Density Functional Theory and ab initio molecular dynamics techniques to model the binding of CO2 on MgO and CaO (100) surfaces and inside water-filled, amine group functionalized silica nanopores. The results elucidate the mechanisms of CO2 trapping and clarify some confusion in the literature. Our work identifies key future calculations that will have the greatest impact on CO2 capture technologies, and provides guidance to science-based design of platforms that can separate the green house gas CO2 from power plant exhaust or even from the atmosphere. Experimentally, we modify commercial MFI zeolite membranes and find that they preferentially transmit H2 over CO2 by a factor of 34. Since zeolite has potential catalytic capability to crack hydrocarbons into CO2 and H2, this finding paves the way for zeolite membranes that can convert biofuel into H2 and separate the products all in one step.

  14. Featured Image: Fireball After a Temporary Capture?

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    This image of a fireball was captured in the Czech Republic by cameras at a digital autonomous observatory in the village of Kunak. This observatory is part of a network of stations known as the European Fireball Network, and this particular meteoroid detection, labeled EN130114, is notable because it has the lowest initial velocity of any natural object ever observed by the network. Led by David Clark (University of Western Ontario), the authors of a recent study speculate that before this meteoroid impacted Earth, it may have been a Temporarily Captured Orbiter (TCO). TCOs are near-Earth objects that make a few orbits of Earth before returning to heliocentric orbits. Only one has ever been observed to date, and though they are thought to make up 0.1% of all meteoroids, EN130114 is the first event ever detected that exhibits conclusive behavior of a TCO. For more information on EN130114 and why TCOs are important to study, check out the paper below!CitationDavid L. Clark et al 2016 AJ 151 135. doi:10.3847/0004-6256/151/6/135

  15. Rare gene capture in predominantly androgenetic species

    PubMed Central

    Hedtke, Shannon M.; Glaubrecht, Matthias; Hillis, David M.

    2011-01-01

    The long-term persistence of completely asexual species is unexpected. Although asexuality has short-term evolutionary advantages, a lack of genetic recombination leads to the accumulation over time of deleterious mutations. The loss of individual fitness as a result of accumulated deleterious mutations is expected to lead to reduced population fitness and possible lineage extinction. Persistent lineages of asexual, all-female clones (parthenogenetic and gynogenetic species) avoid the negative effects of asexual reproduction through the production of rare males, or otherwise exhibit some degree of genetic recombination. Another form of asexuality, known as androgenesis, results in offspring that are clones of the male parent. Several species of the Asian clam genus Corbicula reproduce via androgenesis. We compared gene trees of mitochondrial and nuclear loci from multiple sexual and androgenetic species across the global distribution of Corbicula to test the hypothesis of long-term clonality of the androgenetic species. Our results indicate that low levels of genetic capture of maternal nuclear DNA from other species occur within otherwise androgenetic lineages of Corbicula. The rare capture of genetic material from other species may allow androgenetic lineages of Corbicula to mitigate the effects of deleterious mutation accumulation and increase potentially adaptive variation. Models comparing the relative advantages and disadvantages of sexual and asexual reproduction should consider the possibility of rare genetic recombination, because such events seem to be nearly ubiquitous among otherwise asexual species. PMID:21606355

  16. Capturing Change: Integrating Art and Science

    NASA Astrophysics Data System (ADS)

    Gillerman, J.

    2011-12-01

    The evolving capabilities of interactive media have broadened the potential, and the challenges, of sharing scientific knowledge. From video capture to mobile devices, new technologies have enabled artists to tackle previously demanding or out-of-reach topics and new avenues of dissemination of both art and science. These changes and capabilities affect not only the context and possibilities of scientific data collection, but also how information is presented and communicated innovatively to the public. When recording video of science material whether it is of a Ridley Sea Turtle laying eggs on a beach in Costa Rica, an active lava flow from the volcano Kilauea in Hawaii, or solar eclipses in remote locations around the world, one has to be prepared technically and artistically, not to mention patient in specialized and/or challenging conditions to capture video that satisfies the scientific and artistic imagination. This presentation will include material from varied natural phenomena, creative interfacing in a multimedia context integrating art, science, culture and technology to reach a broad and diverse public, and teaching the integration of art and science through varied art media. (http://www.vipervertex.com).

  17. Capture myopathy in live-stranded cetaceans.

    PubMed

    Herráez, P; Espinosa de los Monteros, A; Fernández, A; Edwards, J F; Sacchini, S; Sierra, E

    2013-05-01

    A group of 51 cetaceans that had been stranded alive on the coasts of the Canary Islands, experienced human capture/rescue interactions and then died, were necropsied over a 12-year period. Of these cetaceans, 25 had haemodynamic lesions indicative of multiorganic vascular shock, degenerative muscle lesions affecting both skeletal and cardiac muscles and myoglobinuric nephrosis typical of capture myopathy (CM). Because macroscopic lesions in muscles and kidneys were not always obvious, a standard protocol was developed where the longissimus dorsi muscle was examined histologically for segmental hypercontraction, contraction band necrosis and segmental muscular degeneration and cardiomyocytes studied for hypereosinophilic wavy fibres, sarcolemmal and perinuclear vacuolation and contraction band necrosis. Light microscopic skeletal and cardiac muscle lesions in all CM animals were confirmed as ante mortem by immunohistochemical assay for myoglobin loss from and fibrinogen entry into affected myofibres. All animals had tubular nephrosis with casts and tubular myoglobin. The oxidative stress-related marker HSP70 was demonstrated immunohistochemically in tubular epithelium. Although the syndrome related to death of live-stranded cetaceans is multifactorial, this study documents that a clinicopathological syndrome comparable to CM of terrestrial wildlife has a role in stranding outcomes. PMID:23146174

  18. Hubble Space Telescope Close to Capture

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Hubble Space Telescope (HST), with its normal routine temporarily interrupted, is about to be captured by the Space Shuttle Columbia prior to a week of servicing and upgrading by the STS-109 crew. The telescope was captured by the shuttle's Remote Manipulator System (RMS) robotic arm and secured on a work stand in Columbia's payload bay where 4 of the 7-member crew performed 5 space walks completing system upgrades to the HST. Included in those upgrades were: The replacement of the solar array panels; replacement of the power control unit (PCU); replacement of the Faint Object Camera (FOC) with a new advanced camera for Surveys (ACS); and installation of the experimental cooling system for the Hubble's Near-Infrared Camera and Multi-object Spectrometer (NICMOS), which had been dormant since January 1999 when its original coolant ran out. The Marshall Space Flight Center had the responsibility for the design, development, and construction of the the HST, which is the most complex and sensitive optical telescope ever made, to study the cosmos from a low-Earth orbit. Launched March 1, 2002, the STS-109 HST servicing mission lasted 10 days, 22 hours, and 11 minutes. It was the 108th flight overall in NASA's Space Shuttle Program.

  19. Microdosimetry for Boron Neutron Capture Therapy

    SciTech Connect

    Maughan, R.L.; Kota, C.

    2000-09-05

    The specific aims of the research proposal were as follows: (1) To design and construct small volume tissue equivalent proportional counters for the dosimetry and microdosimetry of high intensity thermal and epithermal neutron beams used in BNCT, and of modified fast neutron beams designed for boron neutron capture enhanced fast neutron therapy (BNCEFNT). (2) To develop analytical methods for estimating the biological effectiveness of the absorbed dose in BNCT and BNCEFNT based on the measured microdosimetric spectra. (3) To develop an analytical framework for comparing the biological effectiveness of different epithermal neutron beams used in BNCT and BNCEFNT, based on correlated sets of measured microdosimetric spectra and radiobiological data. Specific aims (1) and (2) were achieved in their entirety and are comprehensively documented in Jay Burmeister's Ph.D. dissertation entitled ''Specification of physical and biologically effective absorbed dose in radiation therapies utilizing the boron neutron capture reaction'' (Wayne State University, 1999). Specific aim (3) proved difficult to accomplish because of a lack of sufficient radiobiological data.

  20. Capturing the semiotic relationship between terms

    NASA Astrophysics Data System (ADS)

    Hargood, Charlie; Millard, David E.; Weal, Mark J.

    2010-04-01

    Tags describing objects on the web are often treated as facts about a resource, whereas it is quite possible that they represent more subjective observations. Existing methods of term expansion expand terms based on dictionary definitions or statistical information on term occurrence. Here we propose the use of a thematic model for term expansion based on semiotic relationships between terms; this has been shown to improve a system's thematic understanding of content and tags and to tease out the more subjective implications of those tags. Such a system relies on a thematic model that must be made by hand. In this article, we explore a method to capture a semiotic understanding of particular terms using a rule-based guide to authoring a thematic model. Experimentation shows that it is possible to capture valid definitions that can be used for semiotic term expansion but that the guide itself may not be sufficient to support this on a large scale. We argue that whilst the formation of super definitions will mitigate some of these problems, the development of an authoring support tool may be necessary to solve others.

  1. Laser capture microdissection in the tissue biorepository.

    PubMed

    Liu, Angen

    2010-09-01

    An important need of many cancer research projects is the availability of high-quality, appropriately selected tissue. Tissue biorepositories are organized to collect, process, store, and distribute samples of tumor and normal tissue for further use in fundamental and translational cancer research. This, in turn, provides investigators with an invaluable resource of appropriately examined and characterized tissue specimens and linked patient information. Human tissues, in particular, tumor tissues, are complex structures composed of heterogeneous mixtures of morphologically and functionally distinct cell types. It is essential to analyze specific cell types to identify and define accurately the biologically important processes in pathologic lesions. Laser capture microdissection (LCM) is state-of-the-art technology that provides the scientific community with a rapid and reliable method to isolate a homogeneous population of cells from heterogeneous tissue specimens, thus providing investigators with the ability to analyze DNA, RNA, and protein accurately from pure populations of cells. This is particularly well-suited for tumor cell isolation, which can be captured from complex tissue samples. The combination of LCM and a tissue biorepository offers a comprehensive means by which researchers can use valuable human biospecimens and cutting-edge technology to facilitate basic, translational, and clinical research. This review provides an overview of LCM technology with an emphasis on the applications of LCM in the setting of a tissue biorepository, based on the author's extensive experience in LCM procedures acquired at Fox Chase Cancer Center and Hollings Cancer Center. PMID:20808641

  2. Nucleon pairing in μ- capture by 40Ca

    NASA Astrophysics Data System (ADS)

    Martoff, C. J.; Cummings, W. J.; Poanić, D.; Hanna, S. S.; Ullrich, H.; Furić, M.; Petković, T.; Kozlowski, T.; Perroud, J. P.

    1991-03-01

    Spectra of energetic protons above 35 MeV have been measured following negative muon capture from rest in Ca. The spectrum extends to the kinematic limit near 93 MeV, with a branching ratio of (2.3+/-0.3)×10-4 per capture above 40 MeV. Nuclear cascade calculations of the proton and neutron spectra in this energy region are presented and are consistent with the measured proton spectrum when capture on correlated pp and np pairs in the nucleus is included. The ratio of capture on np to pp pairs is 6.7+/-1.6, which is consistent with results from pion capture.

  3. A method to capture large DNA fragments from genomic DNA.

    PubMed

    Ball, Geneviève; Filloux, Alain; Voulhoux, Romé

    2014-01-01

    The gene capture technique is a powerful tool that allows the cloning of large DNA regions (up to 80 kb), such as entire genomic islands, without using restriction enzymes or DNA amplification. This technique takes advantage of the high recombinant capacity of the yeast. A "capture" vector containing both ends of the target DNA region must first be constructed. The target region is then captured by co-transformation and recombination in yeast between the "capture" vector and appropriate genomic DNA. The selected recombinant plasmid can be verified by sequencing and transferred in the bacteria for multiple applications. This chapter describes a protocol specifically adapted for Pseudomonas aeruginosa genomic DNA capture. PMID:24818928

  4. Capturing King Coal: deploying carbon capture and storage systems in the US at scale

    SciTech Connect

    Fernando, H.; Venezia, J.; Rigdon, C.; Verma, P.

    2008-05-15

    This paper examines the challenges in the deployment of carbon capture and storage (CCS) systems in the USA under the four broad categories of technology, policy, legal and regulatory framework, and investment, and their implications for CCS as part of the solution to mitigate adverse climate change impacts.

  5. Cigarette smoke detection from captured image sequences

    NASA Astrophysics Data System (ADS)

    Iwamoto, Kentaro; Inoue, Hironori; Matsubara, Toru; Tanaka, Toshihisa

    2010-01-01

    We investigate a detection of smoke from captured image sequences. We propose to address the following two problems in order to attain this goal. The first problem is to estimate candidate areas of smoke. The second problem is to judge if smoke exists in the scene. To solve the first problem, we apply the previously proposed framework where image sequences are divided into some small blocks and the smoke detection is done in each small block. In this framework, we propose to use color and edge information of the scene. To solve the second problem, we propose a method for judging if smoke exists in the scene by using the areas of smoke obtained in the last step part. We propose some feature values for judging if smoke exists in the scene. Then, by simulation we find the best combination of feature values. In addition, we study the effect of normalization, which provide better performance in recognition.

  6. IDR muon capture front end and variations

    SciTech Connect

    Neuffer, David; Prior, Gersende; Rogers, Christopher; Snopok, Pavel; Yoshikawa, Cary; /MUONS Inc., Batavia

    2010-12-01

    The (International Design Report) IDR neutrino factory scenario for capture, bunching, phase-energy rotation and initial cooling of {mu}'s produced from a proton source target is explored. It requires a drift section from the target, a bunching section and a {phi}-{delta}E rotation section leading into the cooling channel. The rf frequency changes along the bunching and rotation transport in order to form the {mu}'s into a train of equal-energy bunches suitable for cooling and acceleration. Optimization and variations are discussed. An important concern is rf limitations within the focusing magnetic fields; mitigation procedures are described. The method can be extended to provide muons for a {mu}{sup +}-{mu}{sup -} Collider; variations toward optimizing that extension are discussed.

  7. Upwind and symmetric shock-capturing schemes

    NASA Technical Reports Server (NTRS)

    Yee, H. C.

    1987-01-01

    The development of numerical methods for hyperbolic conservation laws has been a rapidly growing area for the last ten years. Many of the fundamental concepts and state-of-the-art developments can only be found in meeting proceedings or internal reports. This review paper attempts to give an overview and a unified formulation of a class of shock-capturing methods. Special emphasis is on the construction of the basic nonlinear scalar second-order schemes and the methods of extending these nonlinear scalar schemes to nonlinear systems via the extact Riemann solver, approximate Riemann solvers, and flux-vector splitting approaches. Generalization of these methods to efficiently include real gases and large systems of nonequilibrium flows is discussed. The performance of some of these schemes is illustrated by numerical examples for one-, two- and three-dimensional gas dynamics problems.

  8. Accelerator-driven boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Edgecock, Rob

    2014-05-01

    Boron Neutron Capture Therapy is a binary treatment for certain types of cancer. It works by loading the cancerous cells with a boron-10 carrying compound. This isotope has a large cross-section for thermal neutrons, the reaction producing a lithium nucleus and alpha particle that kill the cell in which they are produced. Recent studies of the boron carrier compound indicate that the uptake process works best in particularly aggressive cancers. Most studied is glioblastoma multiforme and a trial using a combination of BNCT and X-ray radiotherapy has shown an increase of nearly a factor of two in mean survival over the state of the art. However, the main technical problem with BNCT remains producing a sufficient flux of neutrons for a reasonable treatment duration in a hospital environment. This paper discusses this issue.

  9. QuikScat Captures an Early Melt

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The SeaWinds instrument on NASA's Quick Scatterometer (QuikScat) spacecraft captured these near-real-time backscatter images of melting on the Larsen C ice shelf in Antarctica's Weddell Sea between October 27 (left) and October 29 (right), 2002--the earliest documented melting event on the ice shelf since radar data began to be collected in the late 1970s. The melting extended as far south as 68 degrees South and resulted from a cyclone that delivered warm air to the region. The image on the right also shows a noticeable recession in the sea-ice margin to the west of the Antarctic peninsula. The darker grey values of the melt region indicate radar backscatter coefficients that are reduced by approximately 10 decibels from their typical end of winter values.

  10. PICO: Portable Instrument for Capturing Occultations

    NASA Astrophysics Data System (ADS)

    Lockhart, Matthew; Person, Michael J.; Elliot, J. L.; Souza, Steven P.

    2010-10-01

    We describe a portable imaging photometer for the observation of stellar occultation events by Kuiper Belt objects (KBOs) and other small bodies. The system is referred to as the Portable Instrument for Capturing Occultations (PICO). It is designed to be transportable to remote observing sites by a single observer. A GPS timing system is used to trigger exposures of a Finger Lakes Instrumentation ML261E-25 camera to facilitate the combination of observational results from multiple sites. The system weighs a total of 11 kg when packed into its single rigid 55.1 × 35.8 × 22.6 cm container, meeting current airline size and weight limits for carry-on baggage. Twelve such systems have been constructed. Nine systems were deployed for observation of a stellar occultation by Kuiper Belt object 55636 in 2009 October. During the same month, one system was used to record a stellar occultation by minor planet 762 Pulcova.

  11. Complex Greenland outlet glacier flow captured

    PubMed Central

    Aschwanden, Andy; Fahnestock, Mark A.; Truffer, Martin

    2016-01-01

    The Greenland Ice Sheet is losing mass at an accelerating rate due to increased surface melt and flow acceleration in outlet glaciers. Quantifying future dynamic contributions to sea level requires accurate portrayal of outlet glaciers in ice sheet simulations, but to date poor knowledge of subglacial topography and limited model resolution have prevented reproduction of complex spatial patterns of outlet flow. Here we combine a high-resolution ice-sheet model coupled to uniformly applied models of subglacial hydrology and basal sliding, and a new subglacial topography data set to simulate the flow of the Greenland Ice Sheet. Flow patterns of many outlet glaciers are well captured, illustrating fundamental commonalities in outlet glacier flow and highlighting the importance of efforts to map subglacial topography. Success in reproducing present day flow patterns shows the potential for prognostic modelling of ice sheets without the need for spatially varying parameters with uncertain time evolution. PMID:26830316

  12. The Chase to Capture Gamma Ray Bursts

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil

    2008-01-01

    Gamma-ray bursts are the most powerful explosions in the universe, thought to be the birth cries of black holes. It has taken 40 years of international cooperation and competition to begin to unravel the mystery of their origin. The most recent chapter in this field is being written by the SWIFT mission, a fast-response satellite with 3 power telescopes. An international team from countries all over the world participates in the chase to capture the fading light of bursts detected by SWIFT. This talk will discuss the challenges and excitement of building this space observatory. New results will be presented on our growing understanding of exploding stars and fiery mergers of orbiting stars.

  13. Electron capture from circular Rydberg atoms

    SciTech Connect

    Hansen, S.B.; Ehrenreich, T.; Horsdal-Pedersen, E. ); MacAdam, K.B. ); Dube, L.J. )

    1993-09-06

    Capture cross sections for circular Rydberg states have been measured as a function of the angle, [ital cphi], between ion velocity and angular momentum of the circular orbital. The system studied is 2.5 keV [sup 23]Na[sup +] on Li(1[ital s][sup 2],[ital nlm]) with [ital n]=25, [ital l]=[ital n][minus]1, and [ital m]=+[ital l], where [ital m] is defined relative to a weak, external magnetic field. A strong dependence on [ital cphi] is found. It is expected that studies such as the present will lead to an improved understanding of the three-body problem in the region of sufficiently large quantum numbers and impact velocities for classical physics to be accurate.

  14. Progress in neutron capture therapy for cancer

    SciTech Connect

    Allen, B.J.; Harrington, B.V.; Moore, D.E.

    1992-09-01

    Prognosis for some cancers is good, but for others, few patients will survive 12 months. This latter group of cancers is characterised by a proclivity to disseminate malignant cells in the host organ. In some cases systemic metastases occur, but in other cases, failure to achieve local control results in death. First among these cancers are the high grade brain tumours, astrocytoma 3,4 and glioblastoma multiforme. Local control of these tumors should lead to cure. Other cancers melanoma metastatic to the brain, for which a useful palliative therapy is not yet available, and pancreatic cancer for which localised control at an early stage could bring about improved prognosis. Patients with these cancers have little grounds for hope. Our primary objective is to reverse this situation with Neutron Capture Therapy (NCT). The purpose of this fourth symposium is to hasten the day whereby patients with these cancers can reasonably hope for substantial remissions.

  15. Progress in neutron capture therapy for cancer

    SciTech Connect

    Allen, B.J.; Harrington, B.V. ); Moore, D.E. )

    1992-01-01

    Prognosis for some cancers is good, but for others, few patients will survive 12 months. This latter group of cancers is characterised by a proclivity to disseminate malignant cells in the host organ. In some cases systemic metastases occur, but in other cases, failure to achieve local control results in death. First among these cancers are the high grade brain tumours, astrocytoma 3,4 and glioblastoma multiforme. Local control of these tumors should lead to cure. Other cancers melanoma metastatic to the brain, for which a useful palliative therapy is not yet available, and pancreatic cancer for which localised control at an early stage could bring about improved prognosis. Patients with these cancers have little grounds for hope. Our primary objective is to reverse this situation with Neutron Capture Therapy (NCT). The purpose of this fourth symposium is to hasten the day whereby patients with these cancers can reasonably hope for substantial remissions.

  16. IDR Muon Capture Front End and Variations

    NASA Astrophysics Data System (ADS)

    Neuffer, D.; Prior, G.; Rogers, C.; Snopok, P.; Yoshikawa, C.

    2011-10-01

    The (International Design Report) IDR neutrino factory scenario for capture, bunching, phase-energy rotation and initial cooling of μ's produced from a proton source target is explored. It requires a drift section from the target, a bunching section and a φ-δE rotation section leading into the cooling channel. The rf frequency changes along the bunching and rotation transport in order to form the 's into a train of equal-energy bunches suitable for cooling and acceleration. Optimization and variations are discussed. An important concern is rf limitations within the focusing magnetic fields; mitigation procedures are described. The method can be extended to provide muons for a μ+-μ- Collider; variations toward optimizing that extension are discussed.

  17. Biochemical Capture and Removal of Carbon Dioxide

    NASA Technical Reports Server (NTRS)

    Trachtenberg, Michael C.

    1998-01-01

    We devised an enzyme-based facilitated transport membrane bioreactor system to selectively remove carbon dioxide (CO2) from the space station environment. We developed and expressed site-directed enzyme mutants for CO2 capture. Enzyme kinetics showed the mutants to be almost identical to the wild type save at higher pH. Both native enzyme and mutant enzymes were immobilized to different supports including nylons, glasses, sepharose, methacrylate, titanium and nickel. Mutant enzyme could be attached and removed from metal ligand supports and the supports reused at least five times. Membrane systems were constructed to test CO2 selectivity. These included proteic membranes, thin liquid films and enzyme-immobilized teflon membranes. Selectivity ratios of more than 200:1 were obtained for CO2 versus oxygen with CO2 at 0.1%. The data indicate that a membrane based bioreactor can be constructed which could bring CO2 levels close to Earth.

  18. Complex Greenland outlet glacier flow captured.

    PubMed

    Aschwanden, Andy; Fahnestock, Mark A; Truffer, Martin

    2016-01-01

    The Greenland Ice Sheet is losing mass at an accelerating rate due to increased surface melt and flow acceleration in outlet glaciers. Quantifying future dynamic contributions to sea level requires accurate portrayal of outlet glaciers in ice sheet simulations, but to date poor knowledge of subglacial topography and limited model resolution have prevented reproduction of complex spatial patterns of outlet flow. Here we combine a high-resolution ice-sheet model coupled to uniformly applied models of subglacial hydrology and basal sliding, and a new subglacial topography data set to simulate the flow of the Greenland Ice Sheet. Flow patterns of many outlet glaciers are well captured, illustrating fundamental commonalities in outlet glacier flow and highlighting the importance of efforts to map subglacial topography. Success in reproducing present day flow patterns shows the potential for prognostic modelling of ice sheets without the need for spatially varying parameters with uncertain time evolution. PMID:26830316

  19. Cellular complexity captured in durable silica biocomposites

    PubMed Central

    Kaehr, Bryan; Townson, Jason L.; Kalinich, Robin M.; Awad, Yasmine H.; Swartzentruber, B. S.; Dunphy, Darren R.; Brinker, C. Jeffrey

    2012-01-01

    Tissue-derived cultured cells exhibit a remarkable range of morphological features in vitro, depending on phenotypic expression and environmental interactions. Translation of these cellular architectures into inorganic materials would provide routes to generate hierarchical nanomaterials with stabilized structures and functions. Here, we describe the fabrication of cell/silica composites (CSCs) and their conversion to silica replicas using mammalian cells as scaffolds to direct complex structure formation. Under mildly acidic solution conditions, silica deposition is restricted to the molecularly crowded cellular template. Inter- and intracellular heterogeneity from the nano- to macroscale is captured and dimensionally preserved in CSCs following drying and subjection to extreme temperatures allowing, for instance, size and shape preserving pyrolysis of cellular architectures to form conductive carbon replicas. The structural and behavioral malleability of the starting material (cultured cells) provides opportunities to develop robust and economical biocomposites with programmed structures and functions. PMID:23045634

  20. Neutron dosimetry in boron neutron capture therapy

    SciTech Connect

    Fairchild, R.G.; Miola, U.J.; Ettinger, K.V.

    1981-01-01

    The recent development of various borated compounds and the utilization of one of these (Na/sub 2/B/sub 12/H/sub 11/SH) to treat brain tumors in clinical studies in Japan has renewed interest in neutron capture therapy. In these procedures thermal neutrons interact with /sup 10/B in boron containing cells through the /sup 10/B(n,..cap alpha..)/sup 7/Li reaction producing charged particles with a maximum range of approx. 10..mu..m in tissue. Borated analogs of chlorpromazine, porphyrin, thiouracil and deoxyuridine promise improved tumor uptake and blood clearance. The therapy beam from the Medical Research Reactor in Brookhaven contains neutrons from a modified and filtered fission spectrum and dosimetric consequences of the use of the above mentioned compounds in conjunction with thermal and epithermal fluxes are discussed in the paper. One of the important problems of radiation dosimetry in capture therapy is determination of the flux profile and, hence, the dose profile in the brain. This has been achieved by constructing a brain phantom made of TE plastic. The lyoluminescence technique provides a convenient way of monitoring the neutron flux distributions; the detectors for this purpose utilize /sup 6/Li and /sup 10/B compounds. Such compounds have been synthesized specially for the purpose of dosimetry of thermal and epithermal beams. In addition, standard lyoluminescent phosphors, like glutamine, could be used to determine the collisional component of the dose as well as the contribution of the /sup 14/N(n,p)/sup 14/C reaction. Measurements of thermal flux were compared with calculations and with measurements done with activation foils.

  1. Non-Statistical Effects in Neutron Capture

    SciTech Connect

    Koehler, P. E.; Guber, K. H.; Harvey, J. A.; Wiarda, D.; Bredeweg, T. A.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Reifarth, R.

    2009-01-28

    There have been many reports of non-statistical effects in neutron-capture measurements. However, reports of deviations of reduced-neutron-width ({gamma}{sub n}{sup 0}) distributions from the expected Porter-Thomas (PT) shape largely have been ignored. Most of these deviations have been reported for odd-A nuclides. Because reliable spin (J) assignments have been absent for most resonances for such nuclides, it is possible that reported deviations from PT might be due to incorrect J assignments. We recently developed a new method for measuring spins of neutron resonances by using the DANCE detector at the Los Alamos Neutron Science Center (LANSCE). Measurements made with a {sup 147}Sm sample allowed us to determine spins of almost all known resonances below 1 keV. Furthermore, analysis of these data revealed that the {gamma}{sub n}{sup 0} distribution was in good agreement with PT for resonances below 350 eV, but in disagreement with PT for resonances between 350 and 700 eV. Our previous (n,{alpha}) measurements had revealed that the {alpha} strength function also changes abruptly at this energy. There currently is no known explanation for these two non-statistical effects. Recently, we have developed another new method for determining the spins of neutron resonances. To implement this technique required a small change (to record pulse-height information for coincidence events) to a much simpler apparatus: A pair of C{sub 6}D{sub 6}{gamma}-ray detectors which we have employed for many years to measure neutron-capture cross sections at the Oak Ridge Electron Linear Accelerator (ORELA). Measurements with a {sup 95}Mo sample revealed that not only does the method work very well for determining spins, but it also makes possible parity assignments. Taken together, these new techniques at LANSCE and ORELA could be very useful for further elucidation of non-statistical effects.

  2. Non-Statistical Effects in Neutron Capture

    SciTech Connect

    Koehler, Paul Edward; Bredeweg, t a; Guber, Klaus H; Harvey, John A; O'Donnell, J. M.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wiarda, Dorothea; Wouters, J. M.

    2009-01-01

    There have been many reports of non-statistical effects in neutron-capture measurements. However, reports of deviations of reduced-neutron-width ({Gamma}n{sup 0}) distributions from the expected Porter-Thomas (PT) shape largely have been ignored. Most of these deviations have been reported for odd-A nuclides. Because reliable spin (J) assignments have been absent for most resonances for such nuclides, it is possible that reported deviations from PT might be due to incorrect J assignments. We recently developed a new method for measuring spins of neutron resonances by using the DANCE detector at the Los Alamos Neutron Science Center (LANSCE). Measurements made with a 147Sm sample allowed us to determine spins of almost all known resonances below 1 keV. Furthermore, analysis of these data revealed that the {Gamma}n{sup 0} distribution was in good agreement with PT for resonances below 350 eV, but in disagreement with PT for resonances between 350 and 700 eV. Our previous (n,{alpha}) measurements had revealed that the {alpha} strength function also changes abruptly at this energy. There currently is no known explanation for these two non-statistical effects. Recently, we have developed another new method for determining the spins of neutron resonances. To implement this technique required a small change (to record pulse-height information for coincidence events) to a much simpler apparatus: A pair of C6D6 ?-ray detectors which we have employed for many years to measure neutron-capture cross sections at the Oak Ridge Electron Linear Accelerator (ORELA). Measurements with a 95Mo sample revealed that not only does the method work very well for determining spins, but it also makes possible parity assignments. Taken together, these new techniques at LANSCE and ORELA could be very useful for further elucidation of non-statistical effects.

  3. Using informatics to capture older adults’ wellness

    PubMed Central

    Demiris, George; Thompson, Hilaire J.; Reeder, Blaine; Wilamowska, Katarzyna; Zaslavsky, Oleg

    2014-01-01

    Purpose The aim of this paper is to demonstrate how informatics applications can support the assessment and visualization of older adults’ wellness. A theoretical framework is presented that informs the design of a technology enhanced screening platform for wellness. We highlight an ongoing pilot demonstration in an assisted living facility where a community room has been converted into a living laboratory for the use of diverse technologies (including a telehealth component to capture vital signs and customized questionnaires, a gait analysis component and cognitive assessment software) to assess the multiple aspects of wellness of older adults. Methods A demonstration project was introduced in an independent retirement community to validate our theoretical framework of informatics and wellness assessment for older adults. Subjects are being recruited to attend a community room and engage in the use of diverse technologies to assess cognitive performance, physiological and gait variables as well as psychometrics pertaining to social and spiritual components of wellness for a period of eight weeks. Data are integrated from various sources into one study database and different visualization approaches are pursued to efficiently display potential correlations between different parameters and capture overall trends of wellness. Results Preliminary findings indicate that older adults are willing to participate in technology-enhanced interventions and embrace different information technology applications given appropriate and customized training and hardware and software features that address potential functional limitations and inexperience with computers. Conclusion Informatics can advance health care for older adults and support a holistic assessment of older adults’ wellness. The described framework can support decision making, link formal and informal caregiving networks and identify early trends and patterns that if addressed could reduce adverse health events

  4. Advanced Docking System With Magnetic Initial Capture

    NASA Technical Reports Server (NTRS)

    Lewis, James L.; Carroll, Monty B.; Morales, Ray; Le, Thang

    2004-01-01

    An advanced docking system is undergoing development to enable softer, safer docking than was possible when using prior docking systems. This system is intended for original use in docking of visiting spacecraft and berthing the Crew Return Vehicle at the International Space Station (ISS). The system could also be adapted to a variety of other uses in outer space and on Earth, including mating submersible vehicles, assembling structures, and robotic berthing/handling of payloads and cargo. Heretofore, two large spacecraft have been docked by causing the spacecraft to approach each other at a speed sufficient to activate capture latches - a procedure that results in large docking loads and is made more difficult because of the speed. The basic design and mode of operation of the present advanced docking system would eliminate the need to rely on speed of approach to activate capture latches, thereby making it possible to reduce approach speed and thus docking loads substantially. The system would comprise an active subsystem on one spacecraft and a passive subsystem on another spacecraft with which the active subsystem will be docked. The passive subsystem would include an extensible ring containing magnetic striker plates and guide petals. The active subsystem would include mating guide petals and electromagnets containing limit switches and would be arranged to mate with the magnetic striker plates and guide petals of the passive assembly. The electromagnets would be carried on (but not rigidly attached to) a structural ring that would be instrumented with load sensors. The outputs of the sensors would be sent, along with position information, as feedback to an electronic control subsystem. The system would also include electromechanical actuators that would extend or retract the ring upon command by the control subsystem.

  5. Capturing Common Loons during prenesting and nesting periods

    USGS Publications Warehouse

    Kenow, K.P.; Wilson, J.M.; Meyer, M.W.

    2009-01-01

    Several techniques have been used to capture Common Loons (Gavia immer), but effectiveness is limited during periods of the breeding season when loons do not have chicks. From 2005 to 2008, we studied loons in northern Wisconsin and used night lighting to capture loons on nests and also designed a lift net for capturing loons prior to nesting. At night, incubating loons were approached by boat and, when within about 30-60 m, we focused a spotlight on the loon and, once at the nest, captured loons using a landing net. Using this technique, we captured 23 loons in 29 attempts (79%). In addition, taped calls and loon decoys were used to entice prenesting, territorial loons into a shoreline-based, lift-net trap at a capture efficiency of 67% (10 captures in 15 attempts) during the second year of use. Our diurnal lift-net trap and night-light nest-capture techniques allowed us to capture adult Common Loons during periods of the breeding season when previous investigators have found loons difficult to catch. These techniques may also be useful for capturing other species of territorial waterbirds, especially other species of loons. ?? 2009 Association of Field Ornithologists. No claim to original U.S. government works.

  6. Electron capture processes in Li2+ + H collisions

    NASA Astrophysics Data System (ADS)

    Yan, Ling Ling; Liu, Ling; Wang, Jian Guo; Janev, Ratko K.; Buenker, Robert J.

    2015-01-01

    The electron capture processes in Li2 + + H collisions have been investigated by using the quantum-mechanical molecular-orbital close-coupling method and the two-center atomic-orbital close-coupling method in the energy ranges of 10-8-10 keV/u and 0.1-300 keV/u, respectively. The capture to singlet and triplet systems of states of Li+(1 s,n l 2S + 1L) is considered separately. Total, n,S-resolved and n,l,S-resolved electron capture cross sections are calculated and compared with the results of available experimental and theoretical studies. The present calculations show that the n = 2 shell of Li+ is the main capture channel for all energies considered in both the singlet and triplet case. While for collision energies E> 5 keV/u, the cross sections for capture to the n = 2 manifold are of the same order of magnitude for both the singlet and triplet states (with the 2 p capture cross section being dominant), for energies below ~5 keV/u the cross sections for capture to the n = 2 triplet manifold is significantly (more than three orders of magnitude at 0.1 keV/u) larger than that for capture to the n = 2 singlet manifold of states (with the 2 s capture cross section being dominant). The capture dynamics at low collision energies is discussed in considerable detail, revealing the important role of rotational couplings in population of l> 0 capture states. The elastic scattering processes have been studied as well in the energy range of 10-8-1 keV/u. The calculated elastic scattering cross section is much larger than the electron capture cross section in both the singlet and triplet case. However, as the collision energy increases, the difference between the elastic and electron capture cross sections decreases rapidly.

  7. Social comparison modulates reward-driven attentional capture.

    PubMed

    Jiao, Jun; Du, Feng; He, Xiaosong; Zhang, Kan

    2015-10-01

    It is well established that attention can be captured by task irrelevant and non-salient objects associated with value through reward learning. However, it is unknown whether social comparison influences reward-driven attentional capture. The present study created four social contexts to examine whether different social comparisons modulate the reward-driven capture of attention. The results showed that reward-driven attentional capture varied with different social comparison conditions. Most prominently, reward-driven attentional capture is dramatically reduced in the disadvantageous social comparison context, in which an individual is informed that the other participant is earning more monetary reward for performing the same task. These findings suggest that social comparison can affect the reward-driven capture of attention. PMID:25711184

  8. Neutron Capture Cross Sections of 236U and 234U

    NASA Astrophysics Data System (ADS)

    Rundberg, R. S.; Bredeweg, T. A.; Bond, E. M.; Haight, R. C.; Hunt, L. F.; Kronenberg, A.; O'Donnell, J. M.; Schwantes, J. M.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.

    2006-03-01

    Accurate neutron capture cross sections of the actinide elements at neutron energies up to 1 MeV are needed to better interpret archived nuclear test data, for post-detonation nuclear attribution, and the Advanced Fuel Cycle Initiative. The Detector for Advance Neutron Capture Experiments, DANCE, has unique capabilities that allow the differentiation of capture gamma rays from fission gamma rays and background gamma rays from scattered neutrons captured by barium isotopes in the barium fluoride scintillators. The DANCE array has a high granularity, 160 scintillators, high efficiency, and nearly 4-π solid angle. Through the use of cuts in cluster multiplicity and calorimetric energy the capture gamma-rays are differentiated from other sources of gamma rays. The preliminary results for the capture cross sections of 236U are in agreement with the ENDF/B-VI evaluation. The preliminary results for 234U lower are than ENDF/B-VI evaluation and are closer to older evaluations.

  9. Neutron Capture Cross Sections of 236U and 234U

    SciTech Connect

    Rundberg, R. S.; Bredeweg, T. A.; Bond, E. M.; Haight, R. C.; Hunt, L. F.; O'Donnell, J. M.; Schwantes, J. M.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Kronenberg, A.

    2006-03-13

    Accurate neutron capture cross sections of the actinide elements at neutron energies up to 1 MeV are needed to better interpret archived nuclear test data, for post-detonation nuclear attribution, and the Advanced Fuel Cycle Initiative. The Detector for Advance Neutron Capture Experiments, DANCE, has unique capabilities that allow the differentiation of capture gamma rays from fission gamma rays and background gamma rays from scattered neutrons captured by barium isotopes in the barium fluoride scintillators. The DANCE array has a high granularity, 160 scintillators, high efficiency, and nearly 4-{pi} solid angle. Through the use of cuts in cluster multiplicity and calorimetric energy the capture gamma-rays are differentiated from other sources of gamma rays. The preliminary results for the capture cross sections of 236U are in agreement with the ENDF/B-VI evaluation. The preliminary results for 234U lower are than ENDF/B-VI evaluation and are closer to older evaluations.

  10. Tidal capture of stars by a massive black hole

    NASA Technical Reports Server (NTRS)

    Novikov, I. D.; Pethick, C. J.; Polnarev, A. G.

    1992-01-01

    The processes leading to tidal capture of stars by a massive black hole and the consequences of these processes in a dense stellar cluster are discussed in detail. When the amplitude of a tide and the subsequent oscillations are sufficiently large, the energy deposited in a star after periastron passage and formation of a bound orbit cannot be estimated directly using the linear theory of oscillations of a spherical star, but rather numerical estimates must be used. The evolution of a star after tidal capture is discussed. The maximum ratio R of the cross-section for tidal capture to that for tidal disruption is about 3 for real systems. For the case of a stellar system with an empty capture loss cone, even in the case when the impact parameter for tidal capture only slightly exceeds the impact parameter for direct tidal disruption, tidal capture would be much more important than tidal disruption.

  11. Rf capture studies for injection into a synchrotron

    SciTech Connect

    Lessner, E.S.; Cho, Y.

    1993-07-01

    The capture process for a rapid cycling protron synchrotron is studied by numerical simulation. The rf-programming is optimized to allow efficient capture such that minimum particle losses and reasonable capture voltage are attained. The total capture time is constrained to be less than 700 {mu}seconds. Two methods of trapping the injected beam by the synchrotron rf system are examined: by stationary adiabatic capture and by synchronous injection in a standing bucket of the ring. In the adiabatic method, the non-linear function of Lilliequist and Symon is employed. The simulation allows the ``tracking back`` of the original distribution of any set of particles, in particular of those not captured at a given time, which is useful in studying injection alternatives such as shaping the phase-space density prior to injection. The simulation results will be used to design a chopper system to facilitate loss-free injection.

  12. Policy Needs for Carbon Capture & Storage

    NASA Astrophysics Data System (ADS)

    Peridas, G.

    2007-12-01

    Climate change is one of the most pressing environmental problems of our time. The widespread consensus that exists on climate science requires deep cuts in greenhouse gas emissions, on the order of 50-80% globally from current levels. Reducing energy demand, increasing energy efficiency and sourcing our energy from renewable sources will, and should, play a key role in achieving these cuts. Fossil fuels however are abundant, relatively inexpensive, and still make up the backbone of our energy system. Phasing out fossil fuel use will be a gradual process, and is likely to take far longer than the timeframe dictated by climate science for reducing emissions. A reliable way of decarbonizing the use of fossil fuels is needed. Carbon capture and storage (CCS) has already proven to be a technology that can safely and effectively accomplish this task. The technological know-how and the underground capacity exist to store billions of tons of carbon dioxide in mature oil and gas fields, and deep saline formations. Three large international commercial projects and several other applications have proved this, but substantial barriers remain to be overcome before CCS becomes the technology of choice in all major emitting sectors. Government has a significant role to play in surmounting these barriers. Without mandatory limits on greenhouse gas emissions and a price on carbon, CCS is likely to linger in the background. The expected initial carbon price levels and their potential volatility under such a scheme dictates that further policies be used in the early years in order for CCS to be implemented. Such policies could include a new source performance standard for power plants, and a low carbon generation obligation that would relieve first movers by spreading the additional cost of the technology over entire sectors. A tax credit for capturing and permanently sequestering anthropogenic CO2 would aid project economics. Assistance in the form of loan guarantees for components

  13. Differential double capture cross sections in p+He collisions

    SciTech Connect

    Schulz, M.; Brand, J. A.; Vajnai, T.

    2007-02-15

    We have measured differential double capture cross sections for 15 to 150 keV p+He collisions. We also analyzed differential double to single capture ratios, where we find pronounced peak structures. An explanation of these structures probably requires a quantum-mechanical description of elastic scattering between the projectile and the target nucleus. Strong final-state correlations have a large effect on the magnitude of the double capture cross sections.

  14. Use of a helicopter to capture flighted cranes

    USGS Publications Warehouse

    Ellis, D.H.; Hjertaas, D.; Johns, B.W.; Urbanek, R.P.

    1998-01-01

    Using a helicopter, we pursued 12 sandhill cranes (Grus canadensis) and captured 6. In forested habitat, cranes could be forced down, but we were unable to deploy the pursuit team, so cranes could not be captured. In open habitat, every crane we pursued was captured. Target cranes were forced to the ground in 0.3-14 minutes. Adjusting pursuit distance (50-150 m) was essential in promoting fatigue and in preventing escape of target cranes.

  15. A vareity of Hg capture solutions are available

    SciTech Connect

    Blankinship, S.

    2009-06-15

    While vacating the Clean Air Mercury Rule (CAMR) has postponed implementation of capturing mercury emitted by coal-fired power plants improvements in ways to capture and monitor mercury have continued. One method of enhancing Hg capture from FGD and SCR is to treat the coal by adding a halogen, such as calcium bromide in Alstom's KNX process prior to combustion. Power plants without FGD usually use sorbent injection, mostly an activated carbon, upstream of a particulate control device. 1 fig.

  16. Entrance channel effects on sub-barrier capture

    NASA Astrophysics Data System (ADS)

    Kuzyakin, R. A.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.

    2015-07-01

    Within the quantum diffusion approach, the capture process of a projectile nucleus by a target nucleus is studied at bombarding energies above and below the Coulomb barrier. The entrance channel effects on the partial and total capture cross sections and the mean angular momentum of the captured system are studied in the reactions leading to 160,156Er, 170Hf, 200Pb, 216Ra, and 220Th compound nuclei.

  17. Neutron capture strategy and technique developments for GNEP

    SciTech Connect

    Couture, Aaron Joseph

    2008-01-01

    The initial three years of neutron capture measurements have been very successful in providing data for the Advanced Fuel Cycle Initiative/Global Nuclear Energy Partnership (AFCI/GNEP) program. Now that the most straightforward measurements have been completed, additional technical challenges face future measurements. In particular, techniques are needed to perform measurements that exhibit at least one of three major problems -- large fission:capture ratios, large capture:capture ratios, and high intrinsic activity samples. This paper will set forward a plan for attacking these technical challenges and moving forward with future measurements.

  18. Stability of a slotted ALOHA system with capture effect

    NASA Astrophysics Data System (ADS)

    Onozato, Yoshikuni; Liu, Jin; Noguchi, Shoichi

    1989-02-01

    The stability of a slotted ALOHA system with capture effect is investigated under a general communication environment where terminals are divided into two groups (low-power and high-power) and the capture effect is modeled by capture probabilities. An approximate analysis is developed using catastrophe theory, in which the effects of system and user parameters on the stability are characterized by the cusp catastrophe. Particular attention is given to the low-power group, since it must bear the strain under the capture effect. The stability conditions of the two groups are given explicitly by bifurcation sets.

  19. Experimental validation of docking and capture using space robotics testbeds

    NASA Astrophysics Data System (ADS)

    Spofford, John

    Docking concepts include capture, berthing, and docking. The definitions of these terms, consistent with AIAA, are as follows: (1) capture (grasping)--the use of a manipulator to make initial contact and attachment between transfer vehicle and a platform; (2) berthing--positioning of a transfer vehicle or payload into platform restraints using a manipulator; and (3) docking--propulsive mechanical connection between vehicle and platform. The combination of the capture and berthing operations is effectively the same as docking; i.e., capture (grasping) + berthing = docking. These concepts are discussed in terms of Martin Marietta's ability to develop validation methods using robotics testbeds.

  20. Progress and new developments in carbon capture and storage

    SciTech Connect

    Plasynski, S.I.; Litynski, J.T.; McIlvried, H.G.; Srivastava, R.D.

    2009-07-01

    Growing concern over the impact on global climate change of the buildup of greenhouse gases (GHGs) in the atmosphere has resulted in proposals to capture carbon dioxide (CO{sub 2}) at large point sources and store it in geologic formations, such as oil and gas reservoirs, unmineable coal seams, and saline formations, referred to as carbon capture and storage (CCS). There are three options for capturing CO{sub 2} from point sources: post-combustion capture, pre-combustion capture, and oxy-combustion. Several processes are available to capture CO{sub 2}, and new or improved processes are under development. However, CO{sub 2} capture is the most expensive part of CCS, typically accounting for 75% of overall cost. CCS will benefit significantly from the development of a lower cost post-combustion CO{sub 2} capture process that can be retrofitted to existing power plants. Once captured, the CO{sub 2} is compressed to about 150 atm and pipelined at supercritical conditions to a suitable storage site. Oil and gas reservoirs, because they have assured seals and are well characterized, are promising early opportunity sites. Saline formations are much more extensive and have a huge potential storage capacity, but are much less characterized. Several commercial and a number of pilot CCS projects are underway around the world.

  1. In situ analysis of bacterial capture in a microfluidic channel

    NASA Astrophysics Data System (ADS)

    Balasubramanian, Ashwin K.; Beskok, Ali; Pillai, Suresh D.

    2007-08-01

    We present a microfluidic approach for the continuous capture of Salmonella Newport cells suspended in a phosphate buffer using externally applied electric fields. The effects of flow rate, applied electric field and wall shear stress on cell capture in the device are analyzed using particle tracking via fluorescent microscopy techniques. Analyzing capture across multiple locations on the electrode surface enabled the estimation of average capture over the entire electrode area as a function of time. The device exhibits approximately a constant capture rate over an extended time frame, which is verified independently using the cell culture methods. An increased capture rate with an increased electric field is observed. The capture rate dependence on the flow rate and capture rate at various locations with different wall shear stress magnitudes does not exhibit statistically significant variations. The capture trends presented in this study can be utilized for designing microfluidic systems for biosensors, designed bacterial bio-films and devices for bacterial sample concentration from large volumes.

  2. Experimental validation of docking and capture using space robotics testbeds

    NASA Technical Reports Server (NTRS)

    Spofford, John

    1991-01-01

    Docking concepts include capture, berthing, and docking. The definitions of these terms, consistent with AIAA, are as follows: (1) capture (grasping)--the use of a manipulator to make initial contact and attachment between transfer vehicle and a platform; (2) berthing--positioning of a transfer vehicle or payload into platform restraints using a manipulator; and (3) docking--propulsive mechanical connection between vehicle and platform. The combination of the capture and berthing operations is effectively the same as docking; i.e., capture (grasping) + berthing = docking. These concepts are discussed in terms of Martin Marietta's ability to develop validation methods using robotics testbeds.

  3. Research needs for neutron capture therapy

    SciTech Connect

    1995-12-01

    Key issues and questions addressed by the workshop related to optimization of Boron Neutron Capture Therapy (BNCT), in general, and to the possibility of success of the present BNCT trials at Brookhaven National Laboratory (BNL) and Massachusetts Institute of Technology (MIT), in particular. Both trials use nuclear fission reactors as neutron sources for BNCT of glioblastoma multiforme (BNL) and of deep seated melanoma (MIT). Presentations and discussions focussed on optimal boron-labeled compounds, mainly for brain tumors such as glioblastoma multiforme, and the best mode of compound delivery to the tumor. Also, optimizing neutron irradiation with dose delivery to the tumor cells and the issues of dosimetry of BNCT especially in the brain were discussed. Planning of treatment and of follow-up of patients, coordination of BNCT at various treatment sites, and the potential of delivering BNCT to various types of cancer with an appropriately tailored protocol were additional issues. The need for multicentric interdisciplinary cooperation among the different medical specialties was highlighted.

  4. Flexcam Image Capture Viewing and Spot Tracking

    NASA Technical Reports Server (NTRS)

    Rao, Shanti

    2008-01-01

    Flexcam software was designed to allow continuous monitoring of the mechanical deformation of the telescope structure at Palomar Observatory. Flexcam allows the user to watch the motion of a star with a low-cost astronomical camera, to measure the motion of the star on the image plane, and to feed this data back into the telescope s control system. This automatic interaction between the camera and a user interface facilitates integration and testing. Flexcam is a CCD image capture and analysis tool for the ST-402 camera from Santa Barbara Instruments Group (SBIG). This program will automatically take a dark exposure and then continuously display corrected images. The image size, bit depth, magnification, exposure time, resolution, and filter are always displayed on the title bar. Flexcam locates the brightest pixel and then computes the centroid position of the pixels falling in a box around that pixel. This tool continuously writes the centroid position to a network file that can be used by other instruments.

  5. Electron capture from solids by positrons

    SciTech Connect

    Howell, R.

    1987-08-01

    The capture of electrons in solids is modified from that in gasses by several factors. The most important is the collective interaction of the electrons which results in a density of electron states in the solid in wide bands. Also the high density of electrons in many solids gives a high frequency of interaction as compared to gasses, and quickly destroys any electron-positron states in the metal matrix. Consequently, most positrons implanted in a metal will rapidly thermalize, and unless they reach the surface will annihilate with an electron in an uncorrelated state. Positronium formation from positrons scattered at a metal surface is analogous to ion neutralization however, most of the positronium comes from positrons passing through the surface from the bulk. The dominant motivation for studying positronium formation has been the hope that the distribution of the electrons at the surface would be obtained through the annihilation properties of positrons trapped at the surface or through analysis of the energy and angular distributions of the positronium emitted into the vacuum. These distributions have been measured and are included in this paper. 17 refs.

  6. No attentional capture from invisible flicker

    PubMed Central

    Alais, David; Locke, Shannon M.; Leung, Johahn; Van der Burg, Erik

    2016-01-01

    We tested whether fast flicker can capture attention using eight flicker frequencies from 20–96 Hz, including several too high to be perceived (>50 Hz). Using a 480 Hz visual display rate, we presented smoothly sampled sinusoidal temporal modulations at: 20, 30, 40, 48, 60, 69, 80, and 96 Hz. We first established flicker detection rates for each frequency. Performance was at or near ceiling until 48 Hz and dropped sharply to chance level at 60 Hz and above. We then presented the same flickering stimuli as pre-cues in a visual search task containing five elements. Flicker location varied randomly and was therefore congruent with target location on 20% of trials. Comparing congruent and incongruent trials revealed a very strong congruency effect (faster search for cued targets) for all detectable frequencies (20–48 Hz) but no effect for faster flicker rates that were detected at chance. This pattern of results (obtained with brief flicker cues: 58 ms) was replicated for long flicker cues (1000 ms) intended to allow for entrainment to the flicker frequency. These results indicate that only visible flicker serves as an exogenous attentional cue and that flicker rates too high to be perceived are completely ineffective. PMID:27377759

  7. Capturing deviation from ergodicity at different scales

    NASA Astrophysics Data System (ADS)

    Scott, Sherry E.; Redd, Thomas C.; Kuznetsov, Leonid; Mezić, Igor; Jones, Christopher K. R. T.

    2009-08-01

    We address here the issue of quantifying the extent to which a given dynamical system falls short of being ergodic and introduce a new multiscale technique which we call the “ergodicity defect”. Our approach is aimed at capturing both deviation from ergodicity and its dependence on scale. The method uses ergodic theory of dynamical systems and applies harmonic analysis, in particular the scaling analysis is motivated by wavelet theory. We base the definition of the ergodicity defect on the Birkhoff characterization. We systematically exploit the role of the observation function by using characteristic functions arising from a dyadic equipartition of the phase space. This allows us to view the dependence of the defect on scale. In order to build intuition, we consider the defect for specific examples with known dynamic properties and we are able to explicitly compute the defect for some of these simple examples. We focus on three distinctive cases of the dependence of the defect on scale: (1) a defect value that increases as the scale becomes finer, (2) a defect value decreasing with scale and (3) a defect value independent of scale, which occurs for instance when a map is ergodic. We explain the information contained in these three scenarios. We see more complicated behavior with an example which has invariant subsets at various scales.

  8. Automated full matrix capture for industrial processes

    NASA Astrophysics Data System (ADS)

    Brown, Roy H.; Pierce, S. Gareth; Collison, Ian; Dutton, Ben; Dziewierz, Jerzy; Jackson, Joseph; Lardner, Timothy; MacLeod, Charles; Morozov, Maxim

    2015-03-01

    Full matrix capture (FMC) ultrasound can be used to generate a permanent re-focusable record of data describing the geometry of a part; a valuable asset for an inspection process. FMC is a desirable acquisition mode for automated scanning of complex geometries, as it allows compensation for surface shape in post processing and application of the total focusing method. However, automating the delivery of such FMC inspection remains a significant challenge for real industrial processes due to the high data overhead associated with the ultrasonic acquisition. The benefits of NDE delivery using six-axis industrial robots are well versed when considering complex inspection geometries, but such an approach brings additional challenges to scanning speed and positional accuracy when combined with FMC inspection. This study outlines steps taken to optimize the scanning speed and data management of a process to scan the diffusion bonded membrane of a titanium test plate. A system combining a KUKA robotic arm and a reconfigurable FMC phased array controller is presented. The speed and data implications of different scanning methods are compared, and the impacts on data visualization quality are discussed with reference to this study. For the 0.5 m2 sample considered, typical acquisitions of 18 TB/m2 were measured for a triple back wall FMC acquisition, illustrating the challenge of combining high data throughput with acceptable scanning speeds.

  9. Capturing the ephemeral human pluripotent state.

    PubMed

    Ávila-González, Daniela; García-López, Guadalupe; García-Castro, Irma Lydia; Flores-Herrera, Héctor; Molina-Hernández, Anayansi; Portillo, Wendy; Díaz, Néstor Fabián

    2016-07-01

    During human development, pluripotency is present only in early stages of development. This ephemeral cell potential can be captured in vitro by obtaining pluripotent stem cells (PSC) with self-renewal properties, the human embryonic stem cells (hESC). However, diverse studies suggest the existence of a plethora of human PSC (hPSC) that can be derived from both embryonic and somatic sources, depending on defined culture conditions, their spatial origin, and the genetic engineering used for reprogramming. This review will focus on hPSC, covering the conventional primed hESC, naïve-like hPSC that resemble the ground-state of development, region-selective PSC, and human induced PSC (hiPSC). We will analyze differences and similarities in their differentiation potential as well as in the molecular circuitry of pluripotency. Finally, we describe the need for human feeder cells to derive and maintain hPSC, because they could emulate the interaction of in vivo pluripotent cells with extraembryonic structures that support development. Developmental Dynamics 245:762-773, 2016. © 2016 Wiley Periodicals, Inc. PMID:27004967

  10. Prospects for carbon capture and storage technologies

    SciTech Connect

    Soren Anderson; Richard Newell

    2003-01-15

    Carbon capture and storage (CCS) technologies remove carbon dioxide from flue gases for storage in geologic formations or the ocean. The study found that CCS is technically feasible and economically attractive within the range of carbon policies discussed domestically and internationally. Current costs are about $200 to $250 per ton of carbon, although costs are sensitive to fuel prices and other assumptions and could be reduced significantly through technical improvements. Near-term prospects favor CCS for certain industrial sources and electric power plants, with storage in depleted oil and gas reservoirs. Deep aquifers may provide an attractive longer-term storage option, whereas ocean storage poses greater technical and environmental uncertainty. Vast quantities of economically recoverable fossil fuels, sizable political obstacles to their abandonment, and inherent delay associated with developing alternative energy sources suggest that CCS should be seriously considered in the portfolio of options for addressing climate change, alongside energy efficiency and carbon-free energy. 61 refs., 5 figs., 5 tabs.

  11. BAG (Continuous Round Robin Packet Capture)

    Energy Science and Technology Software Center (ESTSC)

    2006-03-10

    Bag is a miniature pcap filter which takes pcap input (or input off the wire) using a bpf filter, if specified, and then writes the output to stdout or a file (in pcap format). It depends for some aspects of its functionality on a libpcap library which uses a shared memory packet capture ring bugger. There are two build in modules: chcksum and session. the build in chcksum modules is used to anonymize the ipmore » addresses and repair any checksums in the stream. % bag -r /tmp/*.pcap -Cchucksum, 128.1 65: 10.10 The session module generates sessions which are defined as a series of packets that have two things in common. the first is a unique five-tuple composed oi an IP protocol, IP source address, IP source port, IP destination address, and IP destination port. The second is that if the originating packet is associated with a bi-directional service such as ftpltcp, characteristics and data will be kept for both flows involved with the service. The only protocols evaluated beyond the IP header are ICMP, TCP and UDP. A session can last for as long as bag is running. However, under normal conditions, sessions are generated every time they appear to have closed down. There is a man page included with the distribution which goes into more detail.« less

  12. Synchronous particle and non-adiabatic capture

    SciTech Connect

    Kats, J.M.

    1988-01-01

    In the theory of particle longitudinal motion, a classical definition of synchronous particle (synchronous energy, phase, and orbit) assumes that there is a one-to-one correspondence between the guiding magnetic field and the frequency of the accelerating electrical field. In practice, that correspondence may not be sustained because of errors in the magnetic field, in the frequency, or because sometimes one does not want to keep that relationship for some reason. In this paper, a definition of synchronous particle is introduced when the magnetic field and the frequency are independent functions of time. The result is that the size and shape of the bucket (separatrix) depends not only on the field rate of change but also on the frequency rate of change. This means, for example, that one can have a stationary bucket even with a rising field. Having the frequency, in addition to the field and voltage, as parameters controlling the shape and the size of the bucket, it is shown how to decrease particle losses during injection and capture. 2 refs., 2 figs.

  13. HUBBLE CAPTURES UNVEILING OF PLANETARY NEBULA

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Wide Field and Planetary Camera 2 image captures the infancy of the Stingray nebula (Hen-1357), the youngest known planetary nebula. In this image, the bright central star is in the middle of the green ring of gas. Its companion star is diagonally above it at 10 o'clock. A spur of gas (green) is forming a faint bridge to the companion star due to gravitational attraction. The image also shows a ring of gas (green) surrounding the central star, with bubbles of gas to the lower left and upper right of the ring. The wind of material propelled by radiation from the hot central star has created enough pressure to blow open holes in the ends of the bubbles, allowing gas to escape. The red curved lines represent bright gas that is heated by a 'shock' caused when the central star's wind hits the walls of the bubbles. The nebula is as large as 130 solar systems, but, at its distance of 18,000 light-years, it appears only as big as a dime viewed a mile away. The Stingray is located in the direction of the southern constellation Ara (the Altar). The colors shown are actual colors emitted by nitrogen (red), oxygen (green), and hydrogen (blue). The filters used were F658N ([N II]), F502N ([O III]), and F487N (H-beta). The observations were made in March 1996. Credit: Matt Bobrowsky, Orbital Sciences Corporation and NASA

  14. Is Carbon Capture and Storage Really Needed?

    SciTech Connect

    Tsouris, Costas; Williams, Kent Alan; Aaron, D

    2010-01-01

    Two of the greatest contemporary global challenges are anthropogenic greenhouse gas emissions and energy sustainability. A popular proposed solution to the former problem is carbon capture and storage (CCS). Unfortunately, CCS has little benefit for energy sustainability and introduces significant long-term costs and risks. Thus, we propose the adoption of 'virtual CCS' by directing the resources that would have been spent on CCS to alternative energy technologies. (The term 'virtual' is used here because the concept described in this work satisfies the Merriam-Webster Dictionary definition of virtual: 'being such in essence or effect though not formally recognized or admitted.') In this example, we consider wind and nuclear power and use the funds that would have been required by CCS to invest in installation and operation of these technologies. Many other options exist in addition to wind and nuclear power including solar, biomass, geothermal, and others. These additional energy technologies can be considered in future studies. While CCS involves spending resources to concentrate CO{sub 2} in sinks, such as underground reservoirs, low-carbon alternative energy produces power, which will displace fossil fuel use while simultaneously generating revenues. Thus, these alternative energy technologies achieve the same objective as that of CCS, namely, the avoidance of atmospheric CO{sub 2} emissions.

  15. HUBBLE CAPTURES DETAILED IMAGE OF URANUS' ATMOSPHERE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Hubble Space Telescope has peered deep into Uranus' atmosphere to see clear and hazy layers created by a mixture of gases. Using infrared filters, Hubble captured detailed features of three layers of Uranus' atmosphere. Hubble's images are different from the ones taken by the Voyager 2 spacecraft, which flew by Uranus 10 years ago. Those images - not taken in infrared light - showed a greenish-blue disk with very little detail. The infrared image allows astronomers to probe the structure of Uranus' atmosphere, which consists of mostly hydrogen with traces of methane. The red around the planet's edge represents a very thin haze at a high altitude. The haze is so thin that it can only be seen by looking at the edges of the disk, and is similar to looking at the edge of a soap bubble. The yellow near the bottom of Uranus is another hazy layer. The deepest layer, the blue near the top of Uranus, shows a clearer atmosphere. Image processing has been used to brighten the rings around Uranus so that astronomers can study their structure. In reality, the rings are as dark as black lava or charcoal. This false color picture was assembled from several exposures taken July 3, 1995 by the Wide Field Planetary Camera-2. CREDIT: Erich Karkoschka (University of Arizona Lunar and Planetary Lab) and NASA

  16. Boron thermal/epithermal neutron capture therapy

    SciTech Connect

    Fairchild, R.G.

    1982-01-01

    The development of various particle beams for radiotherapy represents an attempt to improve dose distribution, and to provide high LET radiations which are less sensitive to ambient physical and radiobiological factors such as oxygen tension, cell cycle, and dose rate. In general, a compromise is necessary as effective RBE is reduced in order to spread the dose distribution over the anticipated tumor volume. The approach of delivering stable non-toxic isotopes to tumor, and then activating these atoms subsequently via an external radiation beam has mator advantages; problems associated with high uptake of these isotopes in competing cell pools are obviated, and the general tumor volume can be included in the treatment field of the activating beam. As long as the normal tissues supporting tumor show a low uptake of the isotope to be activated, and as long as the range of the reaction products is short, dose will be restricted to tumor, with a consequent high therapeutic ratio. Neutron Capture Therapy (NCT) is generally carried out by activating boron-10 with low energy neutrons. The range of the high LET, low OER particles from the /sup 10/B(n, ..cap alpha..)/sup 7/Li reaction is approx. 10..mu.., or one cell diameter, a situation that is optimal for cell killing. Significant advantages may be gained by using the NCT procedure in conjunction with improved tissue penetration provided with epithermal or filtered beams, and new compounds showing physiological binding to tumor.

  17. BAG (Continuous Round Robin Packet Capture)

    SciTech Connect

    Wood, C. Philip

    2006-03-10

    Bag is a miniature pcap filter which takes pcap input (or input off the wire) using a bpf filter, if specified, and then writes the output to stdout or a file (in pcap format). It depends for some aspects of its functionality on a libpcap library which uses a shared memory packet capture ring bugger. There are two build in modules: chcksum and session. the build in chcksum modules is used to anonymize the ip addresses and repair any checksums in the stream. % bag -r /tmp/*.pcap -Cchucksum, 128.1 65: 10.10 The session module generates sessions which are defined as a series of packets that have two things in common. the first is a unique five-tuple composed oi an IP protocol, IP source address, IP source port, IP destination address, and IP destination port. The second is that if the originating packet is associated with a bi-directional service such as ftpltcp, characteristics and data will be kept for both flows involved with the service. The only protocols evaluated beyond the IP header are ICMP, TCP and UDP. A session can last for as long as bag is running. However, under normal conditions, sessions are generated every time they appear to have closed down. There is a man page included with the distribution which goes into more detail.

  18. Glycopeptide Capture for Cell Surface Proteomics

    PubMed Central

    Lee, M. C. Gilbert; Sun, Bingyun

    2014-01-01

    Cell surface proteins, including extracellular matrix proteins, participate in all major cellular processes and functions, such as growth, differentiation, and proliferation. A comprehensive characterization of these proteins provides rich information for biomarker discovery, cell-type identification, and drug-target selection, as well as helping to advance our understanding of cellular biology and physiology. Surface proteins, however, pose significant analytical challenges, because of their inherently low abundance, high hydrophobicity, and heavy post-translational modifications. Taking advantage of the prevalent glycosylation on surface proteins, we introduce here a high-throughput glycopeptide-capture approach that integrates the advantages of several existing N-glycoproteomics means. Our method can enrich the glycopeptides derived from surface proteins and remove their glycans for facile proteomics using LC-MS. The resolved N-glycoproteome comprises the information of protein identity and quantity as well as their sites of glycosylation. This method has been applied to a series of studies in areas including cancer, stem cells, and drug toxicity. The limitation of the method lies in the low abundance of surface membrane proteins, such that a relatively large quantity of samples is required for this analysis compared to studies centered on cytosolic proteins. PMID:24836557

  19. Laser capture microdissection for the investigative pathologist.

    PubMed

    Liu, H; McDowell, T L; Hanson, N E; Tang, X; Fujimoto, J; Rodriguez-Canales, J

    2014-01-01

    An important step in translational research is the validation of molecular findings from in vitro experiments using tissue specimens. However, tissue specimens are complex and contain a multitude of diverse cell populations that interfere with the molecular profiling data of a specific cell type. Laser capture microdissection (LCM) alleviates this issue by providing a valuable tool for the enrichment of a specific cell type within complex tissue samples. However, LCM and molecular analysis from tissue specimens can be complex and challenging due to numerous issues related with the tissue processing and its impact on the integrity of biomolecules in the specimen. The intricate nature of this application highlights the essential role a pathologist plays in translational research by contributing an expertise in histopathology, tissue handling, tissue analysis techniques, and clinical correlation of biological findings. The present review examines key practical aspects in tissue handling, specimen selection, quality control, and sample preparation for LCM and downstream molecular analyses that are a primary objective of the investigative pathologist. PMID:24227008

  20. Aqueous ethylenediamine for CO(2) capture.

    PubMed

    Zhou, Shan; Chen, Xi; Nguyen, Thu; Voice, Alexander K; Rochelle, Gary T

    2010-08-23

    Aqueous ethylenediamine (EDA) has been investigated as a solvent for CO(2) capture from flue gas. EDA can be used at 12 M (mol kg(-1) H(2)O) with an acceptable viscosity of 16 cP (1 cP=10(-3) Pa s) with 0.48 mol CO(2) per equivalent of EDA. Similar to monoethanolamine (MEA), EDA can be used up to 120 degrees C in a stripper without significant thermal degradation. Inhibitor A will effectively eliminate oxidative degradation. Above 120 degrees C, loaded EDA degrades with the production of its cyclic urea and other related compounds. Unlike piperazine, when exposed to oxidative degradation, EDA does not result in excessive foaming. Over much of the loading range, the CO(2) absorption rate with 12 M EDA is comparable to 7 M MEA. However, at typical rich loading, 12 M EDA absorbs CO(2) 2 times slower than 7 M MEA. The capacity of 12 M EDA is 0.72 mol CO(2)/(kg H(2)O+EDA) (for P(CO(2) )=0.5 to 5 kPa at 40 degrees C), which is about double that of MEA. The apparent heat of CO(2) desorption in EDA solution is 84 kJ mol(-1) CO(2); greater than most other amine systems. PMID:20677204

  1. Modified Mesoporous Silica for Efficient Siloxane Capture.

    PubMed

    Jafari, Tahereh; Jiang, Ting; Zhong, Wei; Khakpash, Nasser; Deljoo, Bahareh; Aindow, Mark; Singh, Prabhakar; Suib, Steven L

    2016-03-15

    In this study, octamethylcyclotetrasiloxane (D4) was removed by using a novel modified solid adsorbent of mesoporous silica. The adsorbent was synthesized using inverse micelles with some modifications in the synthesis process (temperature of gelation) and in the post treatment conditions (calcination temperature and heating rate) with a concomitant improvement of D4 uptake. This is the first report on regulating the textural properties of the mesoporous silica material UCT-14 to develop an active silica adsorbent. These adjustments resulted in an increase of the silica surface area from 391 to 798 m(2)·g(-1), which leads to a high capacity (686 mg·g(-1)) of D4-capture for the silica synthesized at 80 °C, calcined at 450 °C with the heating rate of 100 °C·min(-1) (Si-Syn80). This adsorbent showed comparable adsorption performance with the widely used commercial silica gel under dry and humid condition. Recyclability tests on the commercial silica gel and mesoporous silica synthesized at 120 °C and calcined at 450 °C with a heating rate of 100 °C·min(-1) (called Si-Syn120 or Si-450 or Si-100 °C·min(-1)) indicated that the Si-Syn120 (capacity drop 10%) is more efficient than silica gel (capacity drop 15%) after three cycles. Although, the presence of moisture (25%) in the nitrogen gas stream led to capacity reduction in both Si-Syn120 and commercial silica gel, the modified UCT-14 shows slightly better resistance to humid condition. PMID:26890152

  2. Hubble Captures Detailed Image of Uranus' Atmosphere

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Hubble Space Telescope has peered deep into Uranus' atmosphere to see clear and hazy layers created by a mixture of gases. Using infrared filters, Hubble captured detailed features of three layers of Uranus' atmosphere.

    Hubble's images are different from the ones taken by the Voyager 2 spacecraft, which flew by Uranus 10 years ago. Those images - not taken in infrared light - showed a greenish-blue disk with very little detail.

    The infrared image allows astronomers to probe the structure of Uranus' atmosphere, which consists of mostly hydrogen with traces of methane. The red around the planet's edge represents a very thin haze at a high altitude. The haze is so thin that it can only be seen by looking at the edges of the disk, and is similar to looking at the edge of a soap bubble. The yellow near the bottom of Uranus is another hazy layer. The deepest layer, the blue near the top of Uranus, shows a clearer atmosphere.

    Image processing has been used to brighten the rings around Uranus so that astronomers can study their structure. In reality, the rings are as dark as black lava or charcoal.

    This false color picture was assembled from several exposures taken July 3, 1995 by the Wide Field Planetary Camera-2.

    The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

    This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  3. Neutron Capture Experiments on Unstable Nuclei

    SciTech Connect

    Jon M. Schwantes; Ralf Sudowe; Heino Nitsche; Darleane C. Hoffman

    2003-12-16

    A primary objective of this project is to study neutron capture cross sections for various stable and unstable isotopes that will contribute to the Science Based Stockpile Stewardship (SBSS) program by providing improved data for modeling and interpretation of nuclear device performance. The information obtained will also be important in astrophysical modeling of nucleosynthesis. During this reporting period, the emphasis has been on preparing a radioactive target of {sup 155}Eu (half-life = 4.7 years), and several stable targets, including isotopically separated {sup 154}Sm, {sup 151}Eu, and {sup 153}Eu. Measurements of their neutron capture cross sections will be conducted in collaboration with researchers at the Los Alamos Neutron Science Center (LANSCE) facility using the Detector for Advanced Neutron Capture Experiments (DANCE). A suitable backing material (beryllium) for the targets has been selected after careful calculations of its contribution to the background of the measurements. In addition, a high voltage plating procedure has been developed and optimized. Stable targets of {sup 151}Eu and {sup 153}Eu and a target of natural Eu ({approx}50% {sup 151}Eu and {approx}50% {sup 153}Eu) have each been plated to a mass thickness of >1 mg/cm{sup 2} and delivered to the DANCE collaboration at Los Alamos National Laboratory (LANL). Natural Eu targets will be tested first to confirm that the target dimensions and backing are appropriate prior to performing measurements on the extremely valuable targets of separated isotopes. In order to prepare a target of the radioactive {sup 155}Eu, it must first be separated from the {sup 154}Sm target material that was irradiated in a very high neutron flux of 1.5x1015 neutrons/cm{sup 2}/s for 50 days. The reaction is {sup 154}Sm (n,f){sup 155}Sm (half-life = 22 minutes) {sup 155}Eu. Considerable progress has been made in developing a suitable high-yield and high-purity separation method for separating Eu from targets

  4. CAPTURE OF NOCTUID AND PYRALID MOTHS USING FEEDING ATTRACTANT LURES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field tests of floral chemicals dispensed in two-component lures were used to capture noctuid and pyralid moths in north-central Florida. Blends of phenylacetaldehyde plus '-myrcene, cis jasmone, linalool, and methyl-2-methoxy benzoate were successful in capturing large numbers of several moth spec...

  5. Student Perception of Topic Difficulty: Lecture Capture in Higher Education

    ERIC Educational Resources Information Center

    McCunn, Patrick; Newton, Genevieve

    2015-01-01

    Perception of topic difficulty is a likely predictor of lecture capture video use, as student perception of difficulty has been shown to affect a variety of outcomes in academic settings. This study measured the relationship between perceived difficulty and the use of lecture capture technology in a second year biochemistry course while…

  6. Real-Time Capture of Student Reasoning While Writing

    ERIC Educational Resources Information Center

    Franklin, Scott V.; Hermsen, Lisa M.

    2014-01-01

    We present a new approach to investigating student reasoning while writing: real-time capture of the dynamics of the writing process. Key-capture or video software is used to record the entire writing episode, including all pauses, deletions, insertions, and revisions. A succinct shorthand, "S notation," is used to highlight significant…

  7. Physical applications of muon catalysis: Muon capture in hydrogen

    NASA Astrophysics Data System (ADS)

    Filchenkov, V. V.

    2016-07-01

    Results of theoretical and experimental research on capture of negative muons in hydrogen are reported with an emphasis on the accompanying phenomenon of muon catalysis in hydrogen and subtleties of the experimental method. A conclusion is drawn that precise determination of the capture rate is important for refining the standard model.

  8. Squiggle Ball Capture: A Simple, Visual Kinetic Theory Experiment

    ERIC Educational Resources Information Center

    Gfroerer, Tim; Rathbun, Ken

    2007-01-01

    When particles move about randomly in the presence of traps, how long does it take for them to be captured? Well, it depends on the average speed of the particles and the dimensions and distribution of the traps. For example, when neutrons are generated in nuclear fission reactions, they must be captured by other fissionable nuclei in order to…

  9. Mountaineer Commerical Scale Carbon Capture and Storage (CCS) Project

    SciTech Connect

    Deanna Gilliland; Matthew Usher

    2011-12-31

    The Final Technical documents all work performed during the award period on the Mountaineer Commercial Scale Carbon Capture & Storage project. This report presents the findings and conclusions produced as a consequence of this work. As identified in the Cooperative Agreement DE-FE0002673, AEP's objective of the Mountaineer Commercial Scale Carbon Capture and Storage (MT CCS II) project is to design, build and operate a commercial scale carbon capture and storage (CCS) system capable of treating a nominal 235 MWe slip stream of flue gas from the outlet duct of the Flue Gas Desulfurization (FGD) system at AEP's Mountaineer Power Plant (Mountaineer Plant), a 1300 MWe coal-fired generating station in New Haven, WV. The CCS system is designed to capture 90% of the CO{sub 2} from the incoming flue gas using the Alstom Chilled Ammonia Process (CAP) and compress, transport, inject and store 1.5 million tonnes per year of the captured CO{sub 2} in deep saline reservoirs. Specific Project Objectives include: (1) Achieve a minimum of 90% carbon capture efficiency during steady-state operations; (2) Demonstrate progress toward capture and storage at less than a 35% increase in cost of electricity (COE); (3) Store CO{sub 2} at a rate of 1.5 million tonnes per year in deep saline reservoirs; and (4) Demonstrate commercial technology readiness of the integrated CO{sub 2} capture and storage system.

  10. Carbon Dioxide Capture by Superbase-Derived Protic Ionic Liquids

    SciTech Connect

    Dai, Sheng; Luo, Huimin; Li, Haoran; Wang, Chongmin; Jiang, Deen

    2010-01-01

    Protic ionic liquids (PILs) from a superbase and fluorinated alcohol, imidazole, pyrrolinone, or phenol were designed to capture CO{sub 2} based on the reactivity of their anions to CO{sub 2}. These PILs are capable of rapid and reversible capture of about one equivalent of CO{sub 2}, which is superior to those sorption systems based on traditional aprotic ILs.

  11. Suspended particle capture by synthetic vegetation in a laboratory flume

    NASA Astrophysics Data System (ADS)

    Fauria, Kristen E.; Kerwin, Rachel E.; Nover, Daniel; Schladow, S. Geoffrey

    2015-11-01

    Vegetated floodplains and wetlands trap particles, a process that is important for water quality and wetland function and morphology. The rates of particle removal by vegetation remain poorly characterized, especially for small particles and vegetation coated with biofilm. In this study, we measured capture rates of road dust by arrays of grass-like synthetic vegetation in a laboratory flume. We performed 40 experiments in which stem density, flow velocity, the presence of biofilm, and initial particle concentration varied, and used an in situ particle size analyzer to measure the concentration of a continuous particle size distribution (1.25-250 µm diameter). We fit first-order decay models to the particle concentration measurements to determine particle capture rates and found that capture rates increased with particle size, stem density, and the presence of biofilm. Capture rates decreased with increasing flow velocity, which suggests that fast flows may resuspend particles from stems. We also calculated percent particle capture efficiencies and fit a new empirical model for capture efficiency to our results. We found that particle capture efficiency was highest for low stem density treatments and propose that stem density affects capture by altering turbulent kinetic energy.

  12. Students Approach to Learning and Their Use of Lecture Capture

    ERIC Educational Resources Information Center

    Vajoczki, Susan; Watt, Susan; Marquis, Nick; Liao, Rose; Vine, Michelle

    2011-01-01

    This study examined lecture capture as a way of enhancing university education, and explored how students with different learning approaches used lecture capturing (i.e., podcasts and vodcasts). Results indicate that both deep and surface learners report increased course satisfaction and better retention of knowledge in courses with traditional…

  13. What is top-down about contingent capture?

    PubMed

    Belopolsky, Artem V; Schreij, Daniel; Theeuwes, Jan

    2010-02-01

    In the present study, we explored the mechanisms involved in the contingent capture phenomenon, using a variant of the classic precuing paradigm of Folk, Remington, and Johnston (1992). Rather than keeping the target fixed over a whole block of trials (as has traditionally been done with contingent capture experiments), we encouraged participants to adopt a top-down set before each trial. If top-down attentional set determines which property captures attention, as is claimed by the contingent capture hypothesis, one would expect that only properties that match the top-down set would capture attention. We showed that even though participants knew what the target would be on the upcoming trial, both relevant and irrelevant properties captured attention (Experiment 1). An intertrial analysis (Experiments 1 and 2) showed that previous contingent capture findings may, to a large extent, be explained by intertrial priming. In addition, when participants were further forced into adopting the required top-down set (Experiments 3 and 4), irrelevant cues were suppressed, suggesting that top-down control might operate through disengagement of attention from the location of a property that does not match top-down goals. The present findings suggest that top-down control and intertrial priming make their own distinct contributions to the contingent capture phenomenon. PMID:20139449

  14. Flexible Octopus-Shaped Hydrogel Particles for Specific Cell Capture.

    PubMed

    Chen, Lynna; An, Harry Z; Haghgooie, Ramin; Shank, Aaron T; Martel, Joseph M; Toner, Mehmet; Doyle, Patrick S

    2016-04-01

    Multiarm hydrogel microparticles with varying geometry are fabricated to specifically capture cells expressing epithelial cell adhesion molecule. Results show that particle shape influences cell-capture efficiency due to differences in surface area, hydrodynamic effects, and steric constraints. These findings can lead to improved particle design for cell separation and diagnostic applications. PMID:26929053

  15. Role of Passive Capturing in a Ubiquitous Learning Environment

    ERIC Educational Resources Information Center

    Ogata, Hiroaki; Hou, Bin; Li, MengMeng; Uosaki, Noriko; Mouri, Kousuke

    2013-01-01

    Ubiquitous Learning Log (ULL) is defined as a digital record of what you have learned in the daily life using ubiquitous technologies. This paper focuses on how to capture learning experiences in our daily life for vocabulary learning. In our previous works, we developed a system named SCROLL (System for Capturing and Reminding Of Learning Log) in…

  16. Orbital Characteristics of Planetesimals Captured by Circumplanetary Gas Disks

    NASA Astrophysics Data System (ADS)

    Suetsugu, Ryo; Ohtsuki, Keiji; Fujita, Tetsuya

    2016-06-01

    Sufficiently massive growing giant planets have circumplanetary disks, and the capture of solid bodies by the disks would likely influence the growth of the planets and formation of satellite systems around them. In addition to dust particles that are supplied to the disk with inflowing gas, recent studies suggest the importance of capture of planetesimals whose motion is decoupled from the gas, but the orbital evolution of captured bodies in circumplanetary gas disks has not been studied in detail. In the present work, using three-body orbital integration and analytic calculations, we examine orbital characteristics and subsequent dynamical evolution of planetesimals captured by gas drag from circumplanetary gas disks. We find that the semimajor axes of the planet-centered orbits of planetesimals at the time of permanent capture are smaller than about one-third of the planet's Hill radius in most cases. Typically, captured bodies rapidly spiral into the planet, and the rate of the orbital decay is faster for the retrograde orbits due to the strong headwind from the circumplanetary gas. When a planetesimal captured in a retrograde orbit suffers from sufficiently strong gas drag before spiraling into the planet, its orbit turns to the prograde direction at a radial location that can be explained using the Stokes number. We also find that those captured in certain types of orbits can survive for a long period of time even under gas drag both in the prograde and retrograde cases, which may be important for the origin of irregular satellites of giant planets.

  17. Simulation of proton RF capture in the AGS Booster

    SciTech Connect

    Khiari, F.Z.; Luccio, A.U.; Weng, W.T.

    1988-01-01

    RF capture of the proton beam in the AGS Booster has been simulated with the longitudinal phase-space tracking code ESME. Results show that a capture in excess of 95% can be achieved with multiturn injection of a chopped beam.

  18. Difficulty of Discrimination Modulates Attentional Capture by Regulating Attentional Focus

    ERIC Educational Resources Information Center

    Sawaki, Risa; Katayama, Jun'ichi

    2009-01-01

    Attentional capture for distractors is enhanced by increasing the difficulty of discrimination between the standard and the target in the three-stimulus oddball paradigm. In this study, we investigated the cognitive mechanism of this modulation of attentional capture. Event-related brain potentials were recorded from participants while they…

  19. SYSTEM LEVEL IMPLICATIONS OF FLEXIBLE CO2 CAPTURE OPERATION

    EPA Science Inventory

    In ERCOT, turning flexible CO2 capture systems off during infrequent periods of peak electricity demand can avoid hundreds of millions to billions of dollars in capital costs to replace the power output lost to CO2 capture energy requirements.  When CO...

  20. Neutron capture therapy: Years of experimentation---Years of reflection

    SciTech Connect

    Farr, L.E.

    1991-12-16

    This report describes early research on neutron capture therapy over a number of years, beginning in 1950, speaking briefly of patient treatments but dwelling mostly on interpretations of our animal experiments. This work carried out over eighteen years, beginning over forty years ago. Yet, it is only fitting to start by relating how neutron capture therapy became part of Brookhaven's Medical Research Center program.

  1. Failure of automatic capture verification in an epicardial pacemaker system.

    PubMed

    Liberman, Leonardo; Hordof, Allan J; Hsu, Daphne S; Pass, Robert H

    2005-09-01

    Epicardial pacing is frequently used in pediatric patients with congenital heart disease. Automatic threshold determination has been reported to be safe in epicardial lead systems. We report a case of falsely low ventricular thresholds determined by automatic capture verification in a patient with complete loss of capture due to a lead fracture. PMID:16177851

  2. Latent Class Analysis: A Method for Capturing Heterogeneity

    ERIC Educational Resources Information Center

    Scotto Rosato, Nancy; Baer, Judith C.

    2012-01-01

    Social work researchers often use variable-centered approaches such as regression and factor analysis. However, these methods do not capture important aspects of relationships that are often imbedded in the heterogeneity of samples. Latent class analysis (LCA) is one of several person-centered approaches that can capture heterogeneity within and…

  3. Some options for the muon collider capture and decay solenoids

    NASA Astrophysics Data System (ADS)

    Green, Michael A.

    1996-05-01

    This report discusses some of the problems associated with using solenoid magnets to capture the secondary particles that are created when an intense beam of 8 to 10 GeV protons interacts with the target at the center of the capture region. Hybrid capture solenoids with inductions of 28 T and a 22 T are described. The first 14 to 15 T of the solenoid induction will be generated by a superconducting magnet. The remainder of the field will be generated by a Bitter type of water cooled solenoid. The capture solenoids include a transition section from the high field solenoid to a 7 T decay channel where pions and kaons that come off of the target decay into muons. A short 7 T solenoidal decay channel between the capture solenoid system and the phase rotation system is described. A concept for separation of negative and positive pions and kaons is briefly discussed.

  4. Neutron capture of 26Mg at thermonuclear energies

    NASA Astrophysics Data System (ADS)

    Mohr, P.; Beer, H.; Oberhummer, H.; Staudt, G.

    1998-08-01

    The neutron capture cross section of 26Mg was measured relative to the known gold cross section at thermonuclear energies using the fast cyclic activation technique. The experiment was performed at the 3.75 MV Van-de-Graaff accelerator, Forschungszentrum Karlsruhe. The experimental capture cross section is the sum of resonant and direct contributions. For the resonance at En,lab=220 keV our new results are in disagreement with the data from Weigmann, Macklin, and Harvey [Phys. Rev. C 14, 1328 (1976)]. An improved Maxwellian averaged capture cross section is derived from the new experimental data taking into account s- and p-wave capture and resonant contributions. The properties of so-called potential resonances which influence the p-wave neutron capture of 26Mg are discussed in detail.

  5. Monoclonal antibody capture and viral clearance by cation exchange chromatography.

    PubMed

    Miesegaes, G R; Lute, S; Strauss, D M; Read, E K; Venkiteshwaran, A; Kreuzman, A; Shah, R; Shamlou, P; Chen, D; Brorson, K

    2012-08-01

    Traditionally, post-production culture harvest capture of therapeutic monoclonal antibodies (mAbs) is performed using Protein A chromatography. We investigated the efficiency and robustness of cation exchange chromatography (CEX) in an effort to evaluate alternative capture methodologies. Up to five commercially available CEX resins were systematically evaluated using an experimentally optimized buffer platform and a design-of-experiment (DoE) approach for their ability to (a) capture a model mAb with a neutral isoelectric point, (b) clear three model viruses (porcine parvovirus, CHO type-C particles, and a bacteriophage). This approach identified a narrow operating space where yield, purity, and viral clearance were optimal under a CEX capture platform, and revealed trends between viral clearance of PPV and product purity (but not yield). Our results suggest that after unit operation optimization, CEX can serve as a suitable capture step. PMID:22488719

  6. Analysis of ballistic capture in Sun-planet models

    NASA Astrophysics Data System (ADS)

    Luo, Z.-F.; Topputo, F.

    2015-09-01

    Analysis of ballistic capture orbits in Sun-planet systems is conducted in this paper. This mechanism utilizes purely gravitational forces, and may occur in non-Keplerian regimes. Ballistic capture orbits are generated by proper manipulation of sets of initial conditions that satisfy a simple definition of stability. Six Sun-planet systems are considered, including the inner planets, Jupiter, and Saturn. The role of planets orbital eccentricity, their true anomaly, and mass ratios is investigated. Moreover, the influence of the post-capture orbit in terms of inclination and orientation is also assessed. Analyses are performed from qualitative and quantitative perspective. The quality of capture orbits is measured by means of the stability index, whereas the capture ratio gives information on their statistical occurrence. Some underlying principles on the selection of the dynamical model, the initial true anomaly, and inclination are obtained. These provide a reference for practical cases.

  7. Estimation methodology in contemporary small mammal capture-recapture studies

    USGS Publications Warehouse

    Nichols, J.D.; Pollock, K.H.

    1983-01-01

    Estimators of population size and survival rate based on the Jolly-Seber capture-recapture model and the 'enumeration method' are described. Enumeration estimators are shown to estimate complicated functions of capture and survival probabilities and, in the case of the population size estimator, population size. Frequently-listed reasons for preferring enumeration estimators are discussed and the Jolly-Seber estimators are shown to be superior even in the case of heterogeneity and trap-happy response, the two sources of unequal capture probability most likely to occur in small mammal studies. New developments in probabilistic capture-recapture models are described, and these models are recommended for future small mammal capture-recapture studies.

  8. Neutron Capture Experiments Using the DANCE Array at Los Alamos

    SciTech Connect

    Dashdorj, D.; Mitchell, G. E.; Baramsai, B.; Chyzh, A.; Walker, C.; Agvaanluvsan, U.; Becker, J. A.; Parker, W.; Sleaford, B.; Wu, C. Y.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Krticka, M.; Becvar, F.

    2009-03-31

    The Detector for Advanced Neutron Capture Experiments (DANCE) is designed for neutron capture measurements on very small and/or radioactive targets. The DANCE array of 160 BaF{sub 2} scintillation detectors is located at the Lujan Center at the Los Alamos Neutron Science Center (LANSCE). Accurate measurements of neutron capture data are important for many current applications as well as for basic understanding of neutron capture. The gamma rays following neutron capture reactions have been studied by the time-of-flight technique using the DANCE array. The high granularity of the array allows measurements of the gamma-ray multiplicity. The gamma-ray multiplicities and energy spectra for different multiplicities can be measured and analyzed for spin and parity determination of the resolved resonances.

  9. Case-Based Capture and Reuse of Aerospace Design Rationale

    NASA Technical Reports Server (NTRS)

    Leake, David B.

    2001-01-01

    The goal of this project was to apply artificial intelligence techniques to facilitate capture and reuse of aerospace design rationale. The project combined case-based reasoning (CBR) and concept maps (CMaps) to develop methods for capturing, organizing, and interactively accessing records of experiences encapsulating the methods and rationale underlying expert aerospace design, in order to bring the captured knowledge to bear to support future reasoning. The project's results contribute both principles and methods for effective design-aiding systems that aid capture and access of useful design knowledge. The project has been guided by the tenets that design-aiding systems must: (1) Leverage a designer's knowledge, rather than attempting to replace it; (2) Be able to reflect different designers' differing conceptualizations of the design task, and to clarify those conceptualizations to others; (3) Include capabilities to capture information both by interactive knowledge modeling and during normal use; and (4) Integrate into normal designer tasks as naturally and unobtrusive as possible.

  10. Contributions of microtubule rotation and dynamic instability to kinetochore capture

    NASA Astrophysics Data System (ADS)

    Sweezy-Schindler, Oliver; Edelmaier, Christopher; Blackwell, Robert; Glaser, Matt; Betterton, Meredith

    2014-03-01

    The capture of lost kinetochores (KCs) by microtubules (MTs) is a crucial part of prometaphase during mitosis. Microtubule dynamic instability has been considered the primary mechanism of KC capture, but recent work discovered that lateral KC attachment to pivoting MTs enabled rapid capture even with significantly reduced MT dynamics. We aim to understand the relative contributions of MT rotational diffusion and dynamic instability to KC capture, as well as KC capture through end-on and/or lateral attachment. Our model consists of rigid MTs and a spherical KC, which are allowed to diffuse inside a spherical nuclear envelope consistent with the geometry of fission yeast. For simplicity, we include a single spindle pole body, which is anchored to the nuclear membrane, and its associated polar MTs. Brownian dynamics treats the diffusion of the MTs and KC and kinetic Monte Carlo models stochastic processes such as dynamic instability. NSF 1546021.

  11. Capture of Hydrogen Using ZrNi

    NASA Technical Reports Server (NTRS)

    Patton, Lisa; Wales, Joshua; Lynch, David; Parrish, Clyde

    2005-01-01

    Water, as ice, is thought to reside in craters at the lunar poles along with CH4 and H2 . A proposed robotic mission for 2012 will utilize metal/metal hydrides for H2 recovery. Specifications are 99% capture of H2 initially at 5 bar and 100C (or greater), and degassing completely at 300C. Of 47-systems examined using the van't Hoff equation, 4 systems, Mg/MgH2, Mg2Ni/Mg2NiH4, ZrNi/ZrNiH2.8, and Pd/PdH0.77, were considered likely candidates for further examination. It is essential, when selecting a system, to also examine questions regarding activation, kinetics, cyclic stability, and gas impurity effects. After considering those issues, ZrN1 was selected as the most promising candidate, as it is easily activated and rapidly forms ZrNiH 2.8 . In addition, it resists oxide poisoning by CO2, and H2O, while some oxidation by O2 is recommended for improved activation . The presence of hydrogen in the as received Zr-Ni alloy from Alfa Aesar posed additional technical problems. X-ray diffraction of the Zr-Ni powder (-325 mesh), with a Zr:Ni wt% ratio of 70:30, was found to consist of ZrH2, ZrNiH2.8, and ZrNi. ZrH2 in the alloy presented the risk that after degassing that both Zr and ZrNi would be present, and thus lead to erroneous results regarding the reactivity of ZrNi with H2 . Fortunately, ZrH2 is a highly stable hydride that does not degas H2 to any significant extent at temperatures below 300C. Based on equilibrium calculations for the decomposition of ZrH2, only 1 millionth of the hydride decomposed at 300C under a N2 atmosphere flowing at 25 ccm for 64 hours, the longest time for pretreatment employed in the investigation. It was possible, from the X-ray results and knowledge of the Zr:Ni ratio, to compute the composition of a pretreated specimen as being 76 wt% ZrNi and the balance ZrH2.

  12. HUBBLE SNAPSHOT CAPTURES LIFE CYCLE OF STARS

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this stunning picture of the giant galactic nebula NGC 3603, the crisp resolution of NASA's Hubble Space Telescope captures various stages of the life cycle of stars in one single view. To the upper right of center is the evolved blue supergiant called Sher 25. The star has a unique circumstellar ring of glowing gas that is a galactic twin to the famous ring around the supernova 1987A. The grayish-bluish color of the ring and the bipolar outflows (blobs to the upper right and lower left of the star) indicates the presence of processed (chemically enriched) material. Near the center of the view is a so-called starburst cluster dominated by young, hot Wolf-Rayet stars and early O-type stars. A torrent of ionizing radiation and fast stellar winds from these massive stars has blown a large cavity around the cluster. The most spectacular evidence for the interaction of ionizing radiation with cold molecular-hydrogen cloud material are the giant gaseous pillars to the right and lower left of the cluster. These pillars are sculptured by the same physical processes as the famous pillars Hubble photographed in the M16 Eagle Nebula. Dark clouds at the upper right are so-called Bok globules, which are probably in an earlier stage of star formation. To the lower left of the cluster are two compact, tadpole-shaped emission nebulae. Similar structures were found by Hubble in Orion, and have been interpreted as gas and dust evaporation from possibly protoplanetary disks (proplyds). The 'proplyds' in NGC 3603 are 5 to 10 times larger in size and correspondingly also more massive. This single view nicely illustrates the entire stellar life cycle of stars, starting with the Bok globules and giant gaseous pillars, followed by circumstellar disks, and progressing to evolved massive stars in the young starburst cluster. The blue supergiant with its ring and bipolar outflow marks the end of the life cycle. The color difference between the supergiant's bipolar outflow and the diffuse

  13. Revisiting the Effect of Capture Heterogeneity on Survival Estimates in Capture-Mark-Recapture Studies: Does It Matter?

    PubMed Central

    Abadi, Fitsum; Botha, Andre; Altwegg, Res

    2013-01-01

    Recently developed capture-mark-recapture methods allow us to account for capture heterogeneity among individuals in the form of discrete mixtures and continuous individual random effects. In this article, we used simulations and two case studies to evaluate the effectiveness of continuously distributed individual random effects at removing potential bias due to capture heterogeneity, and to evaluate in what situation the added complexity of these models is justified. Simulations and case studies showed that ignoring individual capture heterogeneity generally led to a small negative bias in survival estimates and that individual random effects effectively removed this bias. As expected, accounting for capture heterogeneity also led to slightly less precise survival estimates. Our case studies also showed that accounting for capture heterogeneity increased in importance towards the end of study. Though ignoring capture heterogeneity led to a small bias in survival estimates, such bias may greatly impact management decisions. We advocate reducing potential heterogeneity at the sampling design stage. Where this is insufficient, we recommend modelling individual capture heterogeneity in situations such as when a large proportion of the individuals has a low detection probability (e.g. in the presence of floaters) and situations where the most recent survival estimates are of great interest (e.g. in applied conservation). PMID:23646131

  14. Calculation of doublet capture rate for muon capture in deuterium within chiral effective field theory

    NASA Astrophysics Data System (ADS)

    Adam, J.; Tater, M.; Truhlík, E.; Epelbaum, E.; Machleidt, R.; Ricci, P.

    2012-03-01

    The doublet capture rate Λ1 / 2 of the negative muon capture in deuterium is calculated employing the nuclear wave functions generated from accurate nucleon-nucleon (NN) potentials constructed at next-to-next-to-next-to-leading order of heavy-baryon chiral perturbation theory and the weak meson exchange current operator derived within the same formalism. All but one of the low-energy constants that enter the calculation were fixed from pion-nucleon and nucleon-nucleon scattering data. The low-energy constant dˆR (cD), which cannot be determined from the purely two-nucleon data, was extracted recently from the triton β-decay and the binding energies of the three-nucleon systems. The calculated values of Λ1 / 2 show a rather large spread for the used values of the dˆR. Precise measurement of Λ1 / 2 in the future will not only help to constrain the value of dˆR, but also provide a highly nontrivial test of the nuclear chiral EFT framework. Besides, the precise knowledge of the constant dˆR will allow for consistent calculations of other two-nucleon weak processes, such as proton-proton fusion and solar neutrino scattering on deuterons, which are important for astrophysics.

  15. Investigation of Synaptic Tagging/Capture and Cross-capture using Acute Hippocampal Slices from Rodents

    PubMed Central

    Shetty, Mahesh Shivarama; Sharma, Mahima; Hui, Neo Sin; Dasgupta, Ananya; Gopinadhan, Suma; Sajikumar, Sreedharan

    2015-01-01

    Synaptic tagging and capture (STC) and cross-tagging are two important mechanisms at cellular level that explain how synapse-specificity and associativity is achieved in neurons within a specific time frame. These long-term plasticity-related processes are the leading candidate models to study the basis of memory formation and persistence at the cellular level. Both STC and cross-tagging involve two serial processes: (1) setting of the synaptic tag as triggered by a specific pattern of stimulation, and (2) synaptic capture, whereby the synaptic tag interacts with newly synthesized plasticity-related proteins (PRPs). Much of the understanding about the concepts of STC and cross-tagging arises from the studies done in CA1 region of the hippocampus and because of the technical complexity many of the laboratories are still unable to study these processes. Experimental conditions for the preparation of hippocampal slices and the recording of stable late-LTP/LTD are extremely important to study synaptic tagging/cross-tagging. This video article describes the experimental procedures to study long-term plasticity processes such as STC and cross-tagging in the CA1 pyramidal neurons using stable, long-term field-potential recordings from acute hippocampal slices of rats. PMID:26381286

  16. Investigation of Synaptic Tagging/Capture and Cross-capture using Acute Hippocampal Slices from Rodents.

    PubMed

    Shetty, Mahesh Shivarama; Sharma, Mahima; Hui, Neo Sin; Dasgupta, Ananya; Gopinadhan, Suma; Sajikumar, Sreedharan

    2015-01-01

    Synaptic tagging and capture (STC) and cross-tagging are two important mechanisms at cellular level that explain how synapse-specificity and associativity is achieved in neurons within a specific time frame. These long-term plasticity-related processes are the leading candidate models to study the basis of memory formation and persistence at the cellular level. Both STC and cross-tagging involve two serial processes: (1) setting of the synaptic tag as triggered by a specific pattern of stimulation, and (2) synaptic capture, whereby the synaptic tag interacts with newly synthesized plasticity-related proteins (PRPs). Much of the understanding about the concepts of STC and cross-tagging arises from the studies done in CA1 region of the hippocampus and because of the technical complexity many of the laboratories are still unable to study these processes. Experimental conditions for the preparation of hippocampal slices and the recording of stable late-LTP/LTD are extremely important to study synaptic tagging/cross-tagging. This video article describes the experimental procedures to study long-term plasticity processes such as STC and cross-tagging in the CA1 pyramidal neurons using stable, long-term field-potential recordings from acute hippocampal slices of rats. PMID:26381286

  17. Electrofishing capture probability of smallmouth bass in streams

    USGS Publications Warehouse

    Dauwalter, D.C.; Fisher, W.L.

    2007-01-01

    Abundance estimation is an integral part of understanding the ecology and advancing the management of fish populations and communities. Mark-recapture and removal methods are commonly used to estimate the abundance of stream fishes. Alternatively, abundance can be estimated by dividing the number of individuals sampled by the probability of capture. We conducted a mark-recapture study and used multiple repeated-measures logistic regression to determine the influence of fish size, sampling procedures, and stream habitat variables on the cumulative capture probability for smallmouth bass Micropterus dolomieu in two eastern Oklahoma streams. The predicted capture probability was used to adjust the number of individuals sampled to obtain abundance estimates. The observed capture probabilities were higher for larger fish and decreased with successive electrofishing passes for larger fish only. Model selection suggested that the number of electrofishing passes, fish length, and mean thalweg depth affected capture probabilities the most; there was little evidence for any effect of electrofishing power density and woody debris density on capture probability. Leave-one-out cross validation showed that the cumulative capture probability model predicts smallmouth abundance accurately. ?? Copyright by the American Fisheries Society 2007.

  18. Drop impact and capture on a thin flexible fiber

    NASA Astrophysics Data System (ADS)

    Comtet, Jean; Keshavarz, Bavand; Bush, John W. M.

    2015-11-01

    When a drop impacts a thin fiber, a critical impact speed can be defined, below which the drop is entirely captured by the fiber, and above which the drop pinches-off and fractures. We discuss here the capture dynamics of both inviscid and viscous drops on flexible fibers free to deform following impact. We characterize the impact-induced elongation of the drop thread for both high and low viscosity drops, and show that the capture dynamics depends on the relative magnitudes of the bending time of the fiber and deformation time of the drop. In particular, when these two timescales are comparable, drop capture is less prevalent, since the fiber rebounds when the drop deformation is maximal. Conversely, larger elasticity and slower bending time favor drop capture, as fiber rebound happens only after the drop has started to recoil. Finally, in the limit of highly flexible fibers, drop capture depends solely on the relative speed between the drop and the fiber directly after impact, as is prescribed by the momentum transferred. Because the fiber speed directly after impact decreases with increasing fiber length and fiber mass, our study identifies an optimal fiber length for maximizing the efficiency of droplet capture.

  19. Carbon Capture in the Cement Industry: Technologies, Progress, and Retrofitting.

    PubMed

    Hills, Thomas; Leeson, Duncan; Florin, Nicholas; Fennell, Paul

    2016-01-01

    Several different carbon-capture technologies have been proposed for use in the cement industry. This paper reviews their attributes, the progress that has been made toward their commercialization, and the major challenges facing their retrofitting to existing cement plants. A technology readiness level (TRL) scale for carbon capture in the cement industry is developed. For application at cement plants, partial oxy-fuel combustion, amine scrubbing, and calcium looping are the most developed (TRL 6 being the pilot system demonstrated in relevant environment), followed by direct capture (TRL 4-5 being the component and system validation at lab-scale in a relevant environment) and full oxy-fuel combustion (TRL 4 being the component and system validation at lab-scale in a lab environment). Our review suggests that advancing to TRL 7 (demonstration in plant environment) seems to be a challenge for the industry, representing a major step up from TRL 6. The important attributes that a cement plant must have to be "carbon-capture ready" for each capture technology selection is evaluated. Common requirements are space around the preheater and precalciner section, access to CO2 transport infrastructure, and a retrofittable preheater tower. Evidence from the electricity generation sector suggests that carbon capture readiness is not always cost-effective. The similar durations of cement-plant renovation and capture-plant construction suggests that synchronizing these two actions may save considerable time and money. PMID:26630247

  20. CAPTURE OF PLANETESIMALS BY GAS DRAG FROM CIRCUMPLANETARY DISKS

    SciTech Connect

    Fujita, Tetsuya; Ohtsuki, Keiji; Suetsugu, Ryo; Tanigawa, Takayuki

    2013-12-01

    Growing giant planets have circumplanetary disks around them in the late stage of their formation if their mass is sufficiently large. We examine capture of relatively large planetesimals that are decoupled from the gas inflow, due to gas drag from a circumplanetary disk of a growing giant planet. Assuming that the structure of the circumplanetary disk is axisymmetric, and solving the three-body problem including gas drag, we perform analytic and numerical calculations for capture of planetesimals. When planetesimal random velocity is small, planetesimals approaching in the retrograde direction are more easily captured, owing to their larger velocity relative to the gas. Planetesimals with large orbital inclinations interact with the disk for a short period of time and show lower capture rates. The effect of ablation on capture rates seems insignificant, although mass loss due to ablation would be significant in the case of high random velocity. We also examine the effect of non-uniform radial distribution of planetesimals in the protoplanetary disk due to gap opening by the planet. When the random velocity of planetesimals is small, the planetesimal capture rate decreases rapidly as the half width of the gap in the planetesimal disk increases from two planetary Hill radii to three planetary Hill radii; planetesimals with low random velocities cannot approach the planet in the case of a sufficiently wide gap. Our results show that the radial distribution and random velocity of planetesimals in the protoplanetary disk are essentially important for the understanding of capture of planetesimals by circumplanetary disks.