Polarization dynamics regarding ultrafast solitons

Matched filter (MF) and conventional beamforming (CBF) are widely used in active sonar; the performance of the former (temporal resolution) is limited by the signal bandwidth, and that of the latter (angular resolution) is limited by the array aperture. Previous work has shown that angular resolution can be significantly improved by deconvolving the CBF outputs. In this paper, deconvolution is extended to the time domain by deconvolving the MF outputs, and a high-resolution two-dimensional deconvolution method is proposed to simultaneously improve the temporal and angular resolution. Numerical simulations and experimental tank data show that angular resolutions are improved 26 times, and temporal resolutions are improved 10 times compared with the conventional MF and CBF methods. Reverberations are much suppressed to allow target echoes to be detected from the received time series data.A model of a single reed instrument is studied in which the reed is described as an Euler-Bernoulli beam, and the air flow through the instrument is calculated using the Navier-Stokes equations. The hypothetical instrument resembles a clarinet, but is smaller than a real clarinet to keep the numerical modeling feasible on available supercomputers. This article explores the conditions under which the frequency of the reed oscillations and the emitted sound are determined by the resonant frequency of the bore of the instrument. The effect of the contact between the reed and the player's lips is also studied, and quantitative results for the air density and pressure in the mouthpiece and throughout the instrument bore are also presented.Strict lockdown strategies to stop the spread of COVID-19 have caused a decrease in environmental noise levels and introduced new noise conditions in dwellings. The present study has investigated the impact of the forced lockdown in Turkey on noise annoyances due to traffic, neighbors, and personal dwellings, as well as the concern of being heard by neighbors, and overall dwelling satisfaction in an online questionnaire. The stress and anxiety levels of respondents were also investigated. The survey obtained 1053 respondents. Additionally, environmental noise levels were measured over 24-h at two locations and compared with results before the pandemic. The results clearly exhibit that environmental noise levels and annoyance due to the noise levels dropped significantly. The annoyance drop was larger in previously noisier environments than previously tranquil locations. Noise annoyance due to neighbor noise did not change significantly; however, noise annoyance due to one's own dwelling increased. The results also confirmed an overall increase in dwelling satisfactions indicating a correlation between dwelling satisfaction and lower environmental noise levels. Although the results confirmed that noise annoyance was positively correlated with stress and anxiety levels, the change of annoyance between before and during lockdown was shown to be independent from the stress and anxiety level.It has been claimed that filled pauses are transferred from the first (L1) into the second language (L2), suggesting that they are not directly learned by L2 speakers. This would make them usable for cross-linguistic forensic speaker comparisons. However, under the alternative hypothesis that vowels in the L2 are learnable, L2 speakers adapt their pronunciation. This study investigated whether individuals remain consistent in their filled pause realization across languages, by comparing filled pauses (uh, um) in L1 Dutch and L2 English by 58 females. Next to the effect of language, effects of the filled pauses' position in the utterance were considered, as these are expected to affect acoustics and also relate to fluency. Mixed-effects models showed that, whereas duration and fundamental frequency remained similar across languages, vowel realization was language-dependent. Speakers used um relatively more often in English than Dutch, whereas previous research described speakers to be consistent in their umuh ratio across languages. Results furthermore showed that filled-pause acoustics in the L1 and L2 depend on the position in the utterance. Because filled pause realization is partially adapted to the L2, their use as a feature for cross-linguistic forensic speaker comparisons may be restricted.Recent studies on amplitude modulation (AM) detection for tones in noise reported that AM-detection thresholds improve when the AM stimulus is preceded by a noise precursor. The physiological mechanisms underlying this AM unmasking are unknown. https://www.selleckchem.com/products/ly2780301.html One possibility is that adaptation to the level of the noise precursor facilitates AM encoding by causing a shift in neural rate-level functions to optimize level encoding around the precursor level. The aims of this study were to investigate whether such a dynamic-range adaptation is a plausible mechanism for the AM unmasking and whether frequency modulation (FM), thought to be encoded via AM, also exhibits the unmasking effect. Detection thresholds for AM and FM of tones in noise were measured with and without a fixed-level precursor. Listeners showing the unmasking effect were then tested with the precursor level roved over a wide range to modulate the effect of adaptation to the precursor level on the detection of the subsequent AM. It was found that FM detection benefits from a precursor and the magnitude of FM unmasking correlates with that of AM unmasking. Moreover, consistent with dynamic-range adaptation, the unmasking magnitude weakens as the level difference between the precursor and simultaneous masker of the tone increases.A portable infrasound source based on a pneumatic siren design is described. The source is capable of producing narrowband tone bursts over a frequency range of approximately 0.25-10 Hz. The acoustical characteristics of the infrasound source are presented, including measured sound pressure levels and horizontal directivity. The methodologies for processing the received acoustic signals are reported, and comparisons of measurements are made with a simple multipole model of the source. Measurements indicate that the pneumatic infrasound siren can be useful for a variety of applications for which a controlled, known infrasound source is required.