Polarization of baryons produced by high energy neutrinos

Zeitschrift für Physik C Particles and Fields - It is shown that a measurement of the baryon polarization in the reaction $$\mathop v\limits^{( - )} + N \to \mu + B + X$$ gives information on...     

Acoustic recognition of voice disorders: a comparative study of running speech versus sustained vowels

The signals of running speech and sustained vowels of normals and subjects suffering from dysphonia were analyzed statistically with respect to the signal-to-noise ratio (SNR). The distribution of the SNR measured in multiple overlapping frames in the speech signal was described by a linear combination of the distribution frequencies for SNR = 0 dB, 0 dB less than SNR less than 15 dB, and SNR greater than or equal to 15 dB. The values of the linear combination, the SNR of the vowels, and clinical assignment of the voices to normal and pathologic populations based on laryngoscopic and stroboscopic investigation parameters were used to compare the different evaluations of the voices. The SNR distribution in speech remained stable over signal lengths of more than 30 s. The correlation coefficient between the SNR measure for running speech and the SNR of sustained vowels amounted to only 0.63. The error rate in the discrimination between normal and dysphonic voices amounted to 22.6% in application to sustained vowels and 5.6% when the SNR distribution was used. Possible reasons for the observed discrepancies are discussed, and the results are compared to those of other studies.     

Acoustic and perceptual effects of changes in vocal tract constrictions for vowels.

The purpose of this study was to use vocal tract simulation and synthesis as means to determine the acoustic and perceptual effects of changing both the cross-sectional area and location of vocal tract constrictions for six different vowels: Area functions at and near vocal tract constrictions are considered critical to the acoustic output and are also the central point of hypotheses concerning speech targets. Area functions for the six vowels, [symbol: see text] were perturbed by changing the cross-sectional area of the constriction (Ac) and the location of the constriction (Xc). Perturbations for Ac were performed for different values of Xc, producing several series of acoustic continua for the different vowels. Acoustic simulations for the different area functions were made using a frequency domain model of the vocal tract. Each simulated vowel was then synthesized as a 1-s duration steady-state segment. The phoneme boundaries of the perturbed synthesized vowels were determined by formal perception tests. Results of the perturbation analyses showed that formants for each of the vowels were more sensitive to changes in constriction cross-sectional area than changes in constriction location. Vowel perception, however, was highly resistant to both types of changes. Results are discussed in terms of articulatory precision and constriction-related speech production strategies.     

Beam quality changes produced by quartic phase transmittances

The effects that quartic phase distortions generate in tridimensional beam quality parameters of laser fields are investigated. Two cases of special interest are considered: a rotationally symmetric spherically aberrated lens, and a pairof identical but orthogonal cylindrical spherically aberrated lenses in contact with one another. Analytical expressions for the quality parameters at the output plane of these quarticphase optical systems are derived. A number of conditions enabling determination in a definite way whether the quality improves or deteriorates are given for several significant kinds of fields. In particular, some general conclusions are found for perfect Gaussian beams that discriminate whether the two-lens system provides better output beam quality than the single-lens system.     

Intelligibility of vowels sung by a countertenor

Ten American English vowels were sung in a /b/-vowel-/d/ consonantal context by a professional countertenor in full voice (at F0 = 130, 165, 220, 260, and 330 Hz) and in head voice (at F0 = 220, 260, 330, 440, and 520 Hz). Four identification tests were prepared using the entire syllable or the center 200-ms portion of either the full-voice tokens or the head-voice tokens. Listeners attempted to identify each vowel by circling the appropriate word on their answer sheets. Errors were more frequent when the vowels were sung at higher F0. In addition, removal of the consonantal context markedly increased identification errors for both the head-voice and full-voice conditions. Back vowels were misidentified significantly more often than front vowels. For equal F0 values, listeners were significantly more accurate in identifying the head-voice stimuli. Acoustical analysis suggests that the difference of intelligibility between head and full voice may have been due to the head voice having more energy in the first harmonic than the full voice.     

Radiation controlled energy of photoelectrons produced by two-color short pulses

We report on numerical results of energy spectra of photoelectrons emitted by irradiating a hydrogen atom with the superposition of two pulses. The spectra have been obtained by numerical integration of the time dependent Schr?dinger equation. The highest frequency component of the pulse has been assumed to have low intensity and such a frequency that a single photon may ionize the atom. Its duration has been assumed to lie in the range of subfemtoseconds. The lowest frequency component that redistribute the energy of the ionized electrons has an higher intensity and duration of few femtoseconds. We find that when the field are aligned, the electron energy spectra strongly depend on the time lag of the fields, on the carrier-envelope relative phase of the lowest frequency pulse, and on the duration of the X-ray pulse. Moreover it has been found that by changing the angle between the direction of the low and high frequency fields significant modifications to the spectra occur that could be used to measure the relative orientation of the fields.     

The energy spectrum of neutrons produced by cosmic ray muons in LVD

The energy spectrum of neutrons produced by cosmic ray muons in the underground detector LVD (3650 m.w.e.) is obtained for the energy range of 30–450 MeV. The spectrum is derived using the energy release spectrum of neutron interaction products in 1.5 m³ scintillation counters.     

Minimal modelling of atmospheric energy cycle and high-frequency variability

Summary In this paper we build a minimal model able to describe the essential features of the atmospheric energy cycle and high-frequency variability. The model is obtained by projecting the quasi-geostrophic, two-level system on a single Fourier mode in the longitudinal directions and two eigenfunctions of a Sturm-Liouville problem in the meridional direction. The dynamical system, consisting of 14 equations, shows statistical properties in agreement with the observations and other low-order models.     

Carbon microspheres produced by high energy ball milling of graphite powder

During high energy ball milling of graphite powder, carbon microspheres were produced from necklace-like carbon structures that were gradually peeled off and finally fractured into particles. The current formation process of carbon microspheres is completely different to those reported previously, in which carbon microspheres were fabricated by assembling individual carbon atoms into spheres. PACS 81.07.Wx; 81.05.Uw; 61.46.+w; 61.48.+c; 81.20.Ev     

Horizontal directivity of low- and high-frequency energy in speech and singing

Speech and singing directivity in the horizontal plane was examined using simultaneous multi-channel full-bandwidth recordings to investigate directivity of high-frequency energy, in particular. This method allowed not only for accurate analysis of running speech using the long-term average spectrum, but also for examination of directivity of separate transient phonemes. Several vocal production factors that could affect directivity were examined. Directivity differences were not found between modes of production (speech vs singing) and only slight differences were found between genders and production levels (soft vs normal vs loud), more pronounced in the higher frequencies. Large directivity differences were found between specific voiceless fricatives, with /s,∫/ more directional than /f,θ/ in the 4, 8, 16 kHz octave bands.     

Detection and discrimination of synthetic English vowels by Old World monkeys (Cercopithecus, Macaca) and humans

Abilities to detect and discriminate ten synthetic steady-state English vowels were compared in Old World monkeys (Cercopithecus, Macaca) and humans using standard animal psychophysical procedures and positive-reinforcement operant conditioning techniques. Monkeys' detection thresholds were close to humans' for the front vowels /i-I-E-ae-E), but 10-20 dB higher for the back vowels /V-D-C-U-u/. Subjects were subsequently presented with groups of vowels to discriminate. All monkeys experienced difficulty with spectrally similar pairs such as /V-D/, /E-ae/, and /U-u/, but macaques were superior to Cercopithecus monkeys. Humans discriminated all vowels at 100% correct levels, but their increased response latencies reflected spectral similarity and correlated with higher error rates by monkeys. Varying the intensity level of the vowel stimuli had little effect on either monkey or human discrimination, except at the lowest levels tested. These qualitative similarities in monkey and human vowel discrimination suggest that some monkey species may provide useful models of human vowel processing at the sensory level.     

Lateralization produced by interaural temporal and intensitive disparities of high-frequency, raised-sine stimuli: data and modeling

An acoustic pointing task was used to measure extents of laterality produced by combinations of ongoing envelope-based interaural temporal disparities (ITDs) and interaural intensitive disparities (IIDs) of 4-kHz-centered raised-sine stimuli [Bernstein and Trahiotis, J. Acoust. Soc. Am. 125, 3234-3242 (2009),] while varying, parametrically, their peakedness, depth of modulation, and frequency of modulation. The study was designed to assess whether IIDs act as "weights" within the putative "binaural display" at high spectral frequencies (where the envelopes convey ITD-information) as appears to be the case at low spectral frequencies (where the waveforms, i.e., fine-structure and envelopes, convey ITD-information). The data indicate that envelope-based IIDs do principally act as weights and that they appear to exert their influence on lateral position independently of the influence of ITDs. Quantitative analyses revealed that an augmented form of the cross-correlation-based "position-variable" model of Stern and Shear [J. Acoust. Soc. Am. 100, 2278-2288 (1996)] accounted for 94% of the variance in the data. This success notwithstanding, for a small subset of the data, predictions could be improved by assuming that the listeners utilized information within auditory filters having center frequencies above 4 kHz.     

Lateralization produced by envelope-based interaural temporal disparities of high-frequency, raised-sine stimuli: empirical data and modeling

An acoustic pointing task was used to measure extents of laterality produced by ongoing interaural temporal disparities (ITDs) conveyed by the envelopes of 4-kHz-centered raised-sine stimuli while varying, parametrically, their peakedness, depth of modulation, and frequency of modulation. One purpose of the study was to determine whether such manipulations would produce changes in laterality logically consistent with those found for ITD-discrimination thresholds reported by Bernstein and Trahiotis [J. Acoust. Soc. Am. 125, 3234-3242 (2009)]. The data obtained revealed that they did in that (1) increasing depth of modulation, peakedness, or frequency of modulation between 32 and 128 Hz produced smaller threshold ITDs and greater laterality and (2) increasing frequency of modulation to 256 Hz produced modest increases in threshold ITDs and modest decreases in laterality. The extents of laterality measured were successfully accounted for via an augmentation of the cross-correlation-based "position-variable" modeling approach developed by Stern and Shear [J. Acoust. Soc. Am. 100, 2278-2288 (1996)] to account for ITD-based extents of laterality obtained at low spectral frequencies.     

Detection of gases produced by biological systems with an enzyme-photoacoustic sensor

A biosensor, based on the photoacoustic detection of gases produced by an enzyme system, has been developed. The photoacoustic gas cell is separated from the liquid by a gas-permeable membrane which provides good acoustical decoupling. Thus using urease immobilized on glass beads the CO₂ formed was measured in the substrate concentration range of 10–100mM urea. Further development of the described device should enable this sensitivity to be improved by one to two orders of magnitude.     

Work function changes produced by chemisorption due to site heterogeneity

A quantum theory of elastic scattering of atoms from crystal surfaces is presented, based on a hard corrugated surface model. It is shown in detail how the rainbow effect arises and determines the diffraction probabilities, such a rainbow effect being the quantum analogon of McClure's classical rainbow. Further topics considered are the influence of a potential well and the reasons why diffraction hardly occurs from metal surfaces. The basis for a possible extension to inelastic scattering is sketched.