An Analysis of Vocal Communication in the Adult Brown Noddy (Anous stolidus)

The Auk ◽  
1986 ◽  
Vol 103 (2) ◽  
pp. 359-369 ◽  
Author(s):  
Diane E. Riska
Keyword(s):  
Vocal Communication ◽  
Wide Band ◽  
Basic Unit ◽  
Frequency Range ◽  
Mean Frequency ◽  
Dry Tortugas ◽  
Msec Duration ◽  
Vocal Signals ◽  
The Mean ◽  
Nesting Season

Abstract I analyzed vocal signals of marked adult Brown Noddies (Anous stolidus) throughout their nesting season in the Dry Tortugas, Florida from 1979 to 1982. The basic unit of the adult repertoire is a wide-band click, less than 4 msec duration, ranging in frequency from 200 to 3,300 Hz. I identified nine temporal arrangements of these clicks, which form the notes of the calls. These calls differ little in frequency range, but they differ in the mean frequency of the most intense sound energy band, in note duration, in the number of clicks per note, and in internote interval. These calls are used in different contexts, which sometimes overlap. Frequency, note duration, and internote interval do not differ between sexes. Mean frequency and note length varied among individuals for some calls. No tonal elements characteristic of calls of Brown Noddy nestlings remain in the adult repertoire.

A Multiple-Bands Metamaterial Absorber Based in X, Ku and K-Band

2021 ◽  
Author(s):  
Muhammad Fahim Zafar ◽  
Usman Masud
Keyword(s):  
Single Layer ◽  
Wide Band ◽  
Metamaterial Absorber ◽  
Basic Unit ◽  
Frequency Range ◽  
Structure Form ◽  
Perfect Absorption ◽  
Polarization Insensitive ◽  
Band Absorption ◽  
K Band

Abstract Developing a highly efficient and multiple-bands metamaterial absorber is a hot issue in recent era. In this paper, A multiple-bands metamaterial absorber has been presented which is based in X, Ku and K-band. Firstly, we have designed two single layer basic unit cell of X-shape and cross-shape, then they are arranged in the multi-layers structure form for the purpose of obtaining multiple- bands and wide band absorption. The proposed absorber is able to work in multiple bands because it has six peaks in the frequency range of 8–24 GHz with having near perfect absorption. Moreover, the sixth peak has a wideband absorption which is 2.93 GHz. Furthermore, the proposed absorber is also tested for polarization insensitivity and also for oblique incidence. Absorption was found polarization insensitive with almost perfect absorption.

scholarly journals Automatic wheeze detection based on auditory modelling

2005 ◽  
Vol 219 (3) ◽  
pp. 219-227 ◽  
Author(s):  
Y Qiu ◽  
A R Whittaker ◽  
M Lucas ◽  
K Anderson
Keyword(s):  
Marked Improvement ◽  
Historical Record ◽  
Frequency Range ◽  
Mean Frequency ◽  
Threshold Algorithm ◽  
Global Power ◽  
Potential Benefits ◽  
The Mean ◽  
Partial Success ◽  
Improved Algorithm

Automatic wheeze detection has several potential benefits compared with reliance on human auscultation: it is experience independent, an automated historical record can easily be kept, and it allows quantification of wheeze severity. Previous attempts to detect wheezes automatically have had partial success but have not been reliable enough to become widely accepted as a useful tool. In this paper an improved algorithm for automatic wheeze detection based on auditory modelling is developed, called the frequency- and duration-dependent threshold algorithm. The mean frequency and duration of each wheeze component are obtained automatically. The detected wheezes are marked on a spectrogram. In the new algorithm, the concept of a frequency- and duration-dependent threshold for wheeze detection is introduced. Another departure from previous work is that the threshold is based not on global power but on power corresponding to a particular frequency range. The algorithm has been tested on 36 subjects, 11 of whom exhibited characteristics of wheeze. The results show a marked improvement in the accuracy of wheeze detection when compared with previous algorithms.

scholarly journals An Analysis of Pulsar Nulling Statistics

1992 ◽  
Vol 128 ◽  
pp. 265-270
Author(s):  
James D. Biggs
Keyword(s):  
Wide Band ◽  
Emission Mechanism ◽  
Frequency Range ◽  
Pulse Period ◽  
Pulse Profile ◽  
Pulsar Emission ◽  
Rotation Axes ◽  
Upper Limit ◽  
The Mean ◽  
Explicit Correlation

AbstractWe have sought correlations between the fraction of null pulses with other pulsar parameters for an ensemble of 72 pulsars using survival analysis methods. The strongest correlation was found between the null fraction and pulse period. Correlations were also found between other parameters that typically have strong dependencies on pulse period, and this tends to indicate that the null fraction increases with age as was first suggested by Ritchings (1976). However, no explicit correlation was found between pulsar characteristic age and null fraction. A significant anti-correlation was found between the angle subtended by the magnetic and rotation axes and the null fraction.Many of the pulsars presented here were found to null. In particular, all pulse profile classes in the scheme devised by Rankin (1983a) have members that null. Differences in the mean age of these pulsar classes are not very pronounced, and the influence of class on pulse nulling statistics is probably less than that suggested by Rankin (1986), but cannot entirely be ruled out. Also, there is considerable variation in the fraction of null pulses from pulsars within each class, but generally class St pulsars null the least. Of special note is the fact that two pulsars PSR 0833-45 and PSR 1556-44 apparently do not null. The upper limit for PSR 0833–45 is quite low; no nulls were detected in observations of over 120,000 pulses.The similarity of the nulling parameters of pulsars observed at two frequencies near 400 MHz and 843 MHz suggests that the pulsar emission mechanism is wide band over this frequency range.

Microwave wide band absorption by carbon from Corn cob-1

2016 ◽  
Vol 12 (2) ◽  
pp. 4204-4212 ◽  
Author(s):  
Maheshwar Sharon ◽  
Ritesh Vishwakarma ◽  
Abhijeet Rajendra Phatak ◽  
Golap Kalita ◽  
Nallin Sharma ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Agricultural Waste ◽  
Wide Band ◽  
Nickel Nitrate ◽  
Equivalent Amount ◽  
Frequency Range ◽  
Corn Cob ◽  
Different Temperatures ◽  
Band Absorption ◽  
5 Ghz

Corn cob, an agricultural waste, is paralyzed at different temperatures (700oC, 800oC and 900oC). Microwave absorption of carbon in the frequency range of 2 GHz to 8 GHz is reported. Carbon activated  with 5%  nickel nitrate showed more than 90% absorption of microwave in the frequency range from 6 GHz to 8 GHz, while carbon activated  with 10% Nickel nitrate treated corn cob showed 90% absorption  in the frequency range of 2.5 GHz to 5 GHz. Carbon showing the best absorption are characterized by XRD, Raman spectra and SEM . It is suggested that corn cob treatment   alone with KOH did not improve the microwave absorption, whereas treatment along with nickel nitrate improved the absorption property much better. It is proposed that treatment with nickel nitrate helps in creating suitable pores in carbon   which improved the absorption behavior because while treating carbon with 1N HCl helps to leach out nickel creating equivalent amount of pores in the carbon.

scholarly journals Band notched self complementaryultra wideband antenna for wireless applications

2018 ◽  
Vol 7 (2.8) ◽  
pp. 529 ◽  
Author(s):  
Ch Ramakrishna ◽  
G A.E.Satish Kumar ◽  
P Chandra Sekhar Reddy
Keyword(s):  
High Frequency ◽  
Return Loss ◽  
Wide Band ◽  
Ultra Wideband ◽  
Impedance Bandwidth ◽  
Relative Dielectric Permittivity ◽  
Frequency Range ◽  
Ground Structure ◽  
Wireless Applications ◽  
Patch Edge

This paper presents a band notched WLAN self complementaryultra wide band antenna for wireless applications. The proposed antenna encounters a return loss (RL) less than -10dB for entire ultra wideband frequency range except band notched frequency. This paper proposes a hexagon shape patch, edge feeding, self complementary technique and defective ground structure. The antenna has an overall dimensionof 28.3mm × 40mm × 2mm, builton  substrate FR4 with a relative dielectric permittivity 4.4. And framework is simulated finite element method with help of high frequency structured simulator HFSSv17.2.the proposed antenna achieves a impedance bandwidth of 8.6GHz,  band rejected WLAN frequency range 5.6-6.5 GHz with  vswr is less than 2.

Stationary and Transient Response of Cylindrical Shells Under Random Excitation

1988 ◽  
Vol 110 (2) ◽  
pp. 205-209
Author(s):  
A. V. Singh
Keyword(s):  
Transient Response ◽  
Random Vibration ◽  
Time History ◽  
Wide Band ◽  
Random Excitation ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
History Of ◽  
The Mean ◽  
Random Vibration Analysis

This paper presents the random vibration analysis of a simply supported cylindrical shell under a ring load which is uniform around the circumference. The time history of the excitation is assumed to be a stationary wide-band random process. The finite element method and the condition of symmetry along the length of the cylinder are used to calculate the natural frequencies and associated mode shapes. Maximum values of the mean square displacements and velocities occur at the point of application of the load. It is seen that the transient response of the shell under wide band stationary excitation is nonstationary in the initial stages and approaches the stationary solution for large value of time.

An Electrophysiological Measure of Temporal Resolution in Normal Subjects Using Frequency Modulated Signals

2002 ◽  
Vol 11 (1) ◽  
pp. 42-49
Author(s):  
Devin L. McCaslin ◽  
Lawrence L. Feth ◽  
Gary P. Jacobson ◽  
Pamela J. Mishler
Keyword(s):  
Temporal Resolution ◽  
Mismatch Negativity ◽  
Normal Subjects ◽  
Single Step ◽  
Event Related Potential ◽  
Frequency Range ◽  
Temporal Properties ◽  
Step Duration ◽  
The Mean ◽  
Modulated Signals

This investigation was conducted to determine whether an exogenous event-related potential called the mismatch negativity (MMN) would change systematically in response to frequency-modulated signals with varying temporal properties. Both N1 and P2 waveforms were recorded for 50-ms frequency-modulated signals from normal hearing listeners. The standard stimuli for this investigation were continuous sweep tones with center frequencies of 1000 Hz that traversed a frequency range of 200 Hz in a single step. The rare stimuli were signals that traversed the same frequency range in two, four, six, or eight discrete steps. Results suggest that for the 10 participants, 1) the mean MMN peak-to-peak amplitude and mean area decreased significantly with decreases in step duration, 2) MMN area amplitude was the best indicator of psychophysical performance for the two magnitude measures, and 3) MMN onsets and peak latencies did not show either a significant increase or decrease in latency as step duration decreased.

35Cl NQR Spectroscopy on Salts and Molecular Compounds of Trichloroacetic Acid

1986 ◽  
Vol 41 (1-2) ◽  
pp. 215-224 ◽  
Author(s):  
Winfried Fichtner ◽  
Axel Markworth ◽  
Norbert Weiden ◽  
Alarich Weiss
Keyword(s):  
Frequency Shift ◽  
Temperature Dependence ◽  
Linear Relation ◽  
Trichloroacetic Acid ◽  
Mean Frequency ◽  
35Cl Nqr ◽  
The Mean ◽  
Molecular Compounds

The temperature dependence of salts M(1)H(Cl3CCOO)2 and molecular compounds of trichloroacetic acid with amines and benzaldehydes, TCA · X, was studied,The data fit rather well to the known dependence of the mean frequency shift Δ <v(35Cl)> on the pkadifference of X with respect to TCA. A linear relation is observed between the bleaching out temperature Tb of the 35Cl NQR lines and Δ <v(35Cl)> for M(1)H(Cl3CCOO)2 and for TCA · X, X = benzaldehydes.

scholarly journals Discrimination of natural acoustic variation in vocal signals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adam R. Fishbein ◽  
Nora H. Prior ◽  
Jane A. Brown ◽  
Gregory F. Ball ◽  
Robert J. Dooling
Keyword(s):  
Zebra Finch ◽  
Acoustic Communication ◽  
Communication Systems ◽  
Vocal Communication ◽  
Relevant Information ◽  
Speech Sounds ◽  
Vocal Signals ◽  
Acoustic Variation ◽  
Zebra Finch Song ◽  
Human Listener

AbstractStudies of acoustic communication often focus on the categories and units of vocalizations, but subtle variation also occurs in how these signals are uttered. In human speech, it is not only phonemes and words that carry information but also the timbre, intonation, and stress of how speech sounds are delivered (often referred to as “paralinguistic content”). In non-human animals, variation across utterances of vocal signals also carries behaviorally relevant information across taxa. However, the discriminability of these cues has been rarely tested in a psychophysical paradigm. Here, we focus on acoustic communication in the zebra finch (Taeniopygia guttata), a songbird species in which the male produces a single stereotyped motif repeatedly in song bouts. These motif renditions, like the song repetitions of many birds, sound very similar to the casual human listener. In this study, we show that zebra finches can easily discriminate between the renditions, even at the level of single song syllables, much as humans can discriminate renditions of speech sounds. These results support the notion that sensitivity to fine acoustic details may be a primary channel of information in zebra finch song, as well as a shared, foundational property of vocal communication systems across species.

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