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Andrew Stua - One of the best experts on this subject based on the ideXlab platform.
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neonate auditory brainstem responses to ce Chirp and ce Chirp octave band stimuli i versus click and tone burst stimuli
Ear and Hearing, 2016Co-Authors: Kensi M Cobb, Andrew StuaAbstract:OBJECTIVES The purpose of the study was to generate normative auditory brainstem response (ABR) wave component peak latency and amplitude values for neonates with air- and bone-conducted CE-Chirps and air-conducted CE-Chirp octave band stimuli (i.e., 500, 1000, 2000, and 4000 Hz). A second objective was to compare neonate ABRs to CE-Chirp stimuli with ABR responses to traditional click and tone burst stimuli with the same stimulus parameters. DESIGN Participants were 168 healthy neonates. ABRs were obtained to air- and bone-conducted CE-Chirp and click stimuli and air-conducted CE-Chirp octave band and tone burst stimuli. The effects of stimulus level, rate, and polarity were examined with air-conducted CE-Chirps and clicks. The effect of stimulus level was also examined with bone-conducted CE-Chirps and clicks and air-conducted CE-Chirp octave band stimuli. RESULTS In general, ABR wave V amplitudes to air- and bone-conducted CE-Chirp stimuli were significantly larger (p < 0.05) than those evoked to traditional click and tone burst stimuli. Systematic statistically significant (p < 0.05) wave V latency differences existed between the air- and bone-conducted CE-Chirp and CE-Chirp octave band stimuli relative to traditional click and tone burst stimuli. CONCLUSIONS ABRs to air- and bone-conducted CE-Chirps and CE-Chirp octave band stimuli may be valuable in the assessment of newborn infants. However, the prognostic value of such stimuli needs to be validated.
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neonate auditory brainstem responses to ce Chirp and ce Chirp octave band stimuli ii versus adult auditory brainstem responses
Ear and Hearing, 2016Co-Authors: Kensi M Cobb, Andrew StuaAbstract:OBJECTIVES The purpose of the study was to examine the differences in auditory brainstem response (ABR) latency and amplitude indices to the CE-Chirp stimuli in neonates versus young adults as a function of stimulus level, rate, polarity, frequency and gender. DESIGN Participants were 168 healthy neonates and 20 normal-hearing young adults. ABRs were obtained to air- and bone-conducted CE-Chirps and air-conducted CE-Chirp octave band stimuli. The effects of stimulus level, rate, and polarity were examined with air-conducted CE-Chirps. The effect of stimulus level was also examined with bone-conducted CE-Chirps and CE-Chirp octave band stimuli. The effect of gender was examined across all stimulus manipulations. RESULTS In general, ABR wave V amplitudes were significantly larger (p 0.05). CONCLUSIONS Significant differences in ABR latencies and amplitudes exist between newborns and young adults using CE-Chirp stimuli. These differences are consistent with differences to traditional click and tone burst stimuli and reflect maturational differences as a function of age. These findings continue to emphasize the importance of interpreting ABR results using age-based normative data.
Kensi M Cobb - One of the best experts on this subject based on the ideXlab platform.
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neonate auditory brainstem responses to ce Chirp and ce Chirp octave band stimuli i versus click and tone burst stimuli
Ear and Hearing, 2016Co-Authors: Kensi M Cobb, Andrew StuaAbstract:OBJECTIVES The purpose of the study was to generate normative auditory brainstem response (ABR) wave component peak latency and amplitude values for neonates with air- and bone-conducted CE-Chirps and air-conducted CE-Chirp octave band stimuli (i.e., 500, 1000, 2000, and 4000 Hz). A second objective was to compare neonate ABRs to CE-Chirp stimuli with ABR responses to traditional click and tone burst stimuli with the same stimulus parameters. DESIGN Participants were 168 healthy neonates. ABRs were obtained to air- and bone-conducted CE-Chirp and click stimuli and air-conducted CE-Chirp octave band and tone burst stimuli. The effects of stimulus level, rate, and polarity were examined with air-conducted CE-Chirps and clicks. The effect of stimulus level was also examined with bone-conducted CE-Chirps and clicks and air-conducted CE-Chirp octave band stimuli. RESULTS In general, ABR wave V amplitudes to air- and bone-conducted CE-Chirp stimuli were significantly larger (p < 0.05) than those evoked to traditional click and tone burst stimuli. Systematic statistically significant (p < 0.05) wave V latency differences existed between the air- and bone-conducted CE-Chirp and CE-Chirp octave band stimuli relative to traditional click and tone burst stimuli. CONCLUSIONS ABRs to air- and bone-conducted CE-Chirps and CE-Chirp octave band stimuli may be valuable in the assessment of newborn infants. However, the prognostic value of such stimuli needs to be validated.
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neonate auditory brainstem responses to ce Chirp and ce Chirp octave band stimuli ii versus adult auditory brainstem responses
Ear and Hearing, 2016Co-Authors: Kensi M Cobb, Andrew StuaAbstract:OBJECTIVES The purpose of the study was to examine the differences in auditory brainstem response (ABR) latency and amplitude indices to the CE-Chirp stimuli in neonates versus young adults as a function of stimulus level, rate, polarity, frequency and gender. DESIGN Participants were 168 healthy neonates and 20 normal-hearing young adults. ABRs were obtained to air- and bone-conducted CE-Chirps and air-conducted CE-Chirp octave band stimuli. The effects of stimulus level, rate, and polarity were examined with air-conducted CE-Chirps. The effect of stimulus level was also examined with bone-conducted CE-Chirps and CE-Chirp octave band stimuli. The effect of gender was examined across all stimulus manipulations. RESULTS In general, ABR wave V amplitudes were significantly larger (p 0.05). CONCLUSIONS Significant differences in ABR latencies and amplitudes exist between newborns and young adults using CE-Chirp stimuli. These differences are consistent with differences to traditional click and tone burst stimuli and reflect maturational differences as a function of age. These findings continue to emphasize the importance of interpreting ABR results using age-based normative data.
Kent D Dunlap - One of the best experts on this subject based on the ideXlab platform.
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Chirping response of weakly electric knife fish apteronotus leptorhynchus to low frequency electric signals and to heterospecific electric fish
The Journal of Experimental Biology, 2010Co-Authors: Kent D Dunlap, B T Dibenedictis, S R BaneverAbstract:SUMMARY Brown ghost knife fish (Apteronotus leptorhynchus) can briefly increase their electric organ discharge (EOD) frequency to produce electrocommunication signals termed Chirps. The Chirp rate increases when fish are presented with conspecific fish or high-frequency (700–1100 Hz) electric signals that mimic conspecific fish. We examined whether A. leptorhynchus also Chirps in response to artificial low-frequency electric signals and to heterospecific electric fish whose EOD contains low-frequency components. Fish Chirped at rates above background when presented with low-frequency (10–300 Hz) sine-wave stimuli; at 30 and 150 Hz, the threshold amplitude for response was 1 mV cm–1. Low-frequency (30 Hz) stimuli also potentiated the Chirp response to high-frequency (∼900 Hz) stimuli. Fish increased their Chirp rate when presented with two heterospecific electric fish, Sternopygus macrurus and Brachyhypopomus gauderio, but did not respond to the presence of the non-electric fish Carassius auratus. Fish Chirped to low-frequency (150 Hz) signals that mimic those of S. macrurus and to EOD playbacks of B. gauderio. The response to the B. gauderio playback was reduced when the low-frequency component (
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production of aggressive electrocommunication signals to progressively realistic social stimuli in male apteronotus leptorhynchus
Ethology, 2003Co-Authors: Kent D Dunlap, Jonah LarkinsfordAbstract:Brown ghost knife fish, Apteronotus leptorhynchus, produce a continuous electric organ discharge (EOD) that they use for communication. While interacting aggressively, males also emit brief EOD modulations termed Chirps. The simplicity of this behaior and its underlying neural circuitry has made it an important model system in neuroethology. Chirping is typically assayed by confining a fish in a tube (‘Chirp chamber’) and presenting it with sine wave electrical stimuli that partially mimic EODs of other fish. We presented male fish with progressively more realistic social stimuli to examine whether some of the stimulus complexities during dyadic interaction influence the production of Chirps. In a Chirp chamber, fish Chirped less to a recording of an EOD containing Chirps than to a recording of an EOD alone and to sine wave stimuli. Free-swimming fish Chirped more to stimulus fish than to sine wave stimuli presented through electrodes. Fish Chirped more when interacting directly than when interacting across a perforated barrier. Together, these studies demonstrate that the presence of Chirps, electric field complexity, and/or non-electric social stimuli are important in eliciting Chirp production in brown ghosts.
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social interactions and cortisol treatment increase the production of aggressive electrocommunication signals in male electric fish apteronotus leptorhynchus
Hormones and Behavior, 2002Co-Authors: Kent D Dunlap, Patricia L Pelczar, Rosemary KnappAbstract:Brown ghost knife fish, Apteronotus leptorhynchus, continually emit a weakly electric discharge that serves as a communication signal and is sensitive to sex steroids. Males modulate this signal during bouts of aggression by briefly ( 15 ms) increasing the discharge frequency in signals termed “Chirps.” The present study examined the effects of short-term (1‐7 days) and longterm (6 ‐35 days) male‐male interaction on the continuous electric organ discharge (EOD), Chirping behavior, and plasma levels of cortisol and two androgens, 11-ketotestosterone (11KT) and testosterone. Males housed in isolation or in pairs were tested for short-term and long-term changes in their EOD frequency and Chirping rate to standardized sinusoidal electrical stimuli. Within 1 week, Chirp rate was significantly higher in paired fish than in isolated fish, but EOD frequency was equivalent in these two groups of fish. Plasma cortisol levels were significantly higher in paired fish than in isolated fish, but there was no difference between groups in plasma 11KT levels. Among paired fish, cortisol levels correlated positively with Chirp rate. To determine whether elevated cortisol can cause changes in Chirping behavior, isolated fish were implanted with cortisol-filled or empty Silastic tubes and tested for shortterm and long-term changes in electrocommunication signals and steroid levels. After 2 weeks, fish that received cortisol implants showed higher Chirp rates than blank-implanted fish; there were no difference between groups in EOD frequency. Cortisol implants significantly elevated plasma cortisol levels compared to blank implants but had no effect on plasma 11KT levels. These results suggest that male‐male interaction increases Chirp rate by elevating levels of plasma cortisol, which,
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hormonal and body size correlates of electrocommunication behavior during dyadic interactions in a weakly electric fish apteronotus leptorhynchus
Hormones and Behavior, 2002Co-Authors: Kent D DunlapAbstract:Abstract Brown ghost knife fish, Apteronotus leptorhynchus, produce sexually dimorphic, androgen-sensitive electrocommunication signals termed Chirps. The androgen regulation of Chirping has been studied previously by administering exogenous androgens to females and measuring the Chirping response to artificial electrical signals. The present study examined the production of Chirps during dyadic interactions of fish and correlated Chirp rate with endogenous levels of one particular androgen, 11-ketotestosterone (11KT). Eight males and four females were exposed to short-term (5-min) interactions in both same-sex and opposite-sex dyads. Twenty-four hours after all behavioral tests, fish were bled for determination of plasma 11KT levels. Males and females differed in both their production of Chirps and their ability to elicit Chirps from other fish: males Chirped about 20–30 times more often than females and elicited 2–4 times as many Chirps as females. Among males, Chirp rate was correlated positively with plasma 11KT, electric organ discharge frequency, and body size. Combined with results from experimental manipulation of androgen levels, these results support the hypothesis that endogenous 11KT levels influence electrocommunication behavior during interactions between two male fish.
Jian Zhao - One of the best experts on this subject based on the ideXlab platform.
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Chirp spread spectrum toward the nyquist signaling rate orthogonality condition and applications
IEEE Signal Processing Letters, 2017Co-Authors: Xing Ouyang, Octavia A Dobre, Yong Liang Guan, Jian ZhaoAbstract:With the proliferation of Internet-of-Things (IoT), the Chirp spread spectrum (CSS) technique is re-emerging for communications. Although CSS can offer high processing gain, its poor spectral efficiency and the lack of orthogonality among different Chirps tend to limit its potential. In this paper, we derive the condition to orthogonally multiplex an arbitrary number of linear Chirps. For the first time in the literature, we show that the maximum modulation rate of the linear continuous-time Chirps satisfying the orthogonality condition can approach the Nyquist signaling rate, the same as single-carrier waveforms with Nyquist signaling or orthogonal frequency-division multiplexing signals. The performance of the proposed orthogonal CSS is analyzed in comparison to the emerging LoRa systems for IoT applications with power constraint, and its capability for high-speed communications is also demonstrated in the sense of Nyquist signaling.
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orthogonal Chirp division multiplexing
IEEE Transactions on Communications, 2016Co-Authors: Xing Ouyang, Jian ZhaoAbstract:Chirp waveform plays a significant role in radar and communication systems for its ability of pulse compression and spread spectrum. This paper presents a principle of multiplexing a bank of orthogonal Chirps, termed orthogonal Chirp-division multiplexing (OCDM) for high-speed communication. As Fourier transform is the kernel of orthogonal frequency-division multiplexing (OFDM), which achieves the maximum spectral efficiency (SE) of frequency-division multiplexing, Fresnel transform underlies the proposed OCDM system, which achieves the maximum SE of Chirp spread spectrum. By using discrete Fresnel transform, digital implementation of OCDM is introduced. According to the properties of Fresnel transform, the transmission of OCDM signal in linear time-invariant channel is studied. Efficient digital signal processing is proposed for channel dispersion compensation. The implementation of the OCDM system is discussed with the emphasis on its compatibility to the OFDM system; it is shown that it can be easily integrated into the existing OFDM systems. Finally, the simulations are provided to validate the feasibility of the proposed OCDM. It is shown that the OCDM system can efficiently exploit multipath diversity and thus outperforms the OFDM, and that it is more resilient against the interference due to insufficient guard interval than single-carrier frequency-domain equalization.
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orthogonal Chirp division multiplexing
arXiv: Information Theory, 2016Co-Authors: Xing Ouyang, Jian ZhaoAbstract:Chirp waveform plays a significant role in radar and communication systems for its ability of pulse compression and spread spectrum. This paper presents a principle of orthogonally multiplexing a bank of linear Chirp waveforms within the same bandwidth. The amplitude and phase of the Chirps are modulated for information communication. As Fourier trans-form is the basis for orthogonal frequency division multiplexing (OFDM), Fresnel transform underlies the proposed orthogonal Chirp division multiplexing (OCDM). Digital implementa-tion of the OCDM system using discrete Fresnel transform is proposed. Based on the con-volution theorem of the Fresnel transform, the transmission of the OCDM signal is analyzed under the linear time-invariant or quasi-static channel with additive noise, which can gener-alize typical linear transmission channels. Based on the eigen-decomposition of Fresnel transform, efficient digital signal processing algorithm is proposed for compensating chan-nel dispersion by linear single- tap equalizers. The implementation details of the OCDM system is discussed with emphasis on its compatibility to the OFDM system. Finally, simula-tion are provided to validate the feasibility of the proposed OCDM under wireless channels. It is shown that the OCDM system is able to utilize the multipath diversity and outperforms the OFDM system under the multipath fading channels.
Gerald S Pollack - One of the best experts on this subject based on the ideXlab platform.
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recognition of variable courtship song in the field cricket gryllus assimilis
The Journal of Experimental Biology, 2012Co-Authors: Varvara Yu Vedenina, Gerald S PollackAbstract:SUMMARY We analyzed the courtship song of the field cricket Gryllus assimilis . The song comprises two elements: groups of ca. 10 pulses (Chirps) with low fundamental frequency (3.5–3.7 kHz) alternating with high-frequency (15-17 kHz) pulses (ticks) that usually occur as doublets. Some elements of courtship song are quite variable (high coefficient of variation) both within and between males, whereas others are more stereotypical. In experiments with playback of synthesized courtship songs, we studied the importance of several song parameters for mating success, which we evaluated as the probability with which females mounted muted, courting males. Altering some features that show little variability, such as Chirp-pulse rate or carrier frequency of ticks, resulted in significant decreases in mounting frequency, consistent with the notion that trait values showing little variability are constrained by stabilizing selection exerted by females. However, alteration of one invariant trait, the occurrence of both song components, by omitting either component from test songs only slightly affected female responsiveness. Alteration of a variable song trait, the number of ticks per song phrase, had no effect on female response rate, thus failing to provide support for the idea that variable traits provide a substrate for sexual selection. An unusual characteristic feature of the song of G. assimilis is that Chirp pulses often contain substantial high-frequency power, and indeed may entirely lack power at the fundamental frequency. Playback experiments showed that such songs are, nevertheless, behaviorally effective. To understand the neural basis for this, we recorded the responses of the two principal ascending auditory interneurons of crickets, AN1 and AN2. Our results suggest that the frequency selectivity of the neurons is sufficiently broad to tolerate the spectral variability of courtship Chirps.
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recognition of courtship song in the field cricket teleogryllus oceanicus
Animal Behaviour, 1996Co-Authors: Rohini Balakrishnan, Gerald S PollackAbstract:Abstract The courtship song of the cricket,Teleogryllus oceanicusplays an important role in inducing the female to mount the male, which is necessary for mating. The song consists of a short, amplitude-modulated Chirp, followed by a long trill of constant intensity and high syllable rate. Using playback techniques, it was determined which physical parameters of courtship song are necessary and/or sufficient to evoke normal female mounting of muted, courting males. The higher harmonics of natural courtship song were neither necessary nor sufficient for the effectiveness of the song. The Chirp component alone was sufficient to evoke normal levels of mounting, but the trill was only partially effective on its own. The conspicuous amplitude modulation of the Chirp was not necessary to evoke normal responses. The results suggest that the high effectiveness of the Chirp is due to its characteristic temporal pattern. As in other cricket species, the song repertoire ofT. oceanicusalso includes distinct calling and aggression songs, which contain Chirps that are structurally similar to the courtship Chirp. Both calling and aggression songs evoked normal mounting responses when played back in the context of courtship.
