bluuebunny/crossref_metadata_2025 huggingface dataset:
Recognition of spectrally asynchronous speech by normal-hearing listeners and Nucleus-22 cochlear implant users
Authors: Fu Qian-Jie , Galvin John J.
Published: July 2002

This experiment examined the effects of spectral resolution and fine spectral structure on recognition of spectrally asynchronous sentences by normal-hearing and cochlear implant listeners. Sentence recognition was measured in six normal-hearing subjects listening to either full-spectrum or noise-band processors and five Nucleus-22 cochlear implant listeners fitted with 4-channel continuous interleaved sampling (CIS) processors. For the full-spectrum processor, the speech signals were divided into either 4 or 16 channels. For the noise-band processor, after band-pass filtering into 4 or 16 channels, the envelope of each channel was extracted and used to modulate noise of the same bandwidth as the analysis band, thus eliminating the fine spectral structure available in the full-spectrum processor. For the 4-channel CIS processor, the amplitude envelopes extracted from four bands were transformed to electric currents by a power function and the resulting electric currents were used to modulate pulse trains delivered to four electrode pairs. For all processors, the output of each channel was time-shifted relative to other channels, varying the channel delay across channels from 0 to 240 ms (in 40-ms steps). Within each delay condition, all channels were desynchronized such that the cross-channel delays between adjacent channels were maximized, thereby avoiding local pockets of channel synchrony. Results show no significant difference between the 4- and 16-channel full-spectrum speech processor for normal-hearing listeners. Recognition scores dropped significantly only when the maximum delay reached 200 ms for the 4-channel processor and 240 ms for the 16-channel processor. When fine spectral structures were removed in the noise-band processor, sentence recognition dropped significantly when the maximum delay was 160 ms for the 16-channel noise-band processor and 40 ms for the 4-channel noise-band processor. There was no significant difference between implant listeners using the 4-channel CIS processor and normal-hearing listeners using the 4-channel noise-band processor. The results imply that when fine spectral structures are not available, as in the implant listener’s case, increased spectral resolution is important for overcoming cross-channel asynchrony in speech signals.
Effects of stimulus frequency and complexity on the mismatch negativity and other components of the cortical auditory-evoked potential
Authors: Wunderlich Julia L. , Cone-Wesson Barbara K.
Published: July 2002

This study investigated, first, the effect of stimulus frequency on mismatch negativity (MMN), N1, and P2 components of the cortical auditory event-related potential (ERP) evoked during passive listening to an oddball sequence. The hypothesis was that these components would show frequency-related changes, reflected in their latency and magnitude. Second, the effect of stimulus complexity on those same ERPs was investigated using words and consonant–vowel tokens (CVs) discriminated on the basis of formant change. Twelve normally hearing listeners were tested with tone bursts in the speech frequency range (400/440, 1500/1650, and 3000/3300 Hz), words (/bæd/ vs /dæd/) and CVs (/bæ/ vs /dæ/). N1 amplitude and latency decreased as frequency increased. P2 amplitude, but not latency, decreased as frequency increased. Frequency-related changes in MMN were similar to those for N1, resulting in a larger MMN area to low frequency contrasts. N1 amplitude and latency for speech sounds were similar to those found for low tones but MMN had a smaller area. Overall, MMN was present in 46%–71% of tests for tone contrasts but for only 25%–32% of speech contrasts. The magnitude of N1 and MMN for tones appear to be closely related, and both reflect the tonotopicity of the auditory cortex.
A modal Pritchard approximation for computing array element mutual impedance
Authors: Scandrett C. L. , Day J. L. , Baker S. R.
Published: July 2002

An investigation into the applicability and accuracy of Pritchard’s approximation for closely packed transducer arrays is undertaken. A new, “modal” Pritchard approximation is developed, based upon normal modes of the acoustic medium, and is tested for arrays of acoustically hard spheres to ascertain its accuracy in determining the mutual acoustic radiation impedance between array elements. For ka≈1, it is found that the modal Pritchard approximation works quite well in approximating the mutual radiation impedance of a two-element array, even for relatively close spacing; but for arrays of three or more scatterers in close proximity the approximation may have relatively large errors. The effect of neglecting inter-element scattering is analyzed for the monopole-to-monopole scattering of various configurations of a three-element array and a sixteenelement double line array.
Further analysis of intensity fluctuations from a 3252-km acoustic propagation experiment in the eastern North Pacific Ocean
Authors: Colosi John A. , Tappert Fred , Dzieciuch Matthew
Published: July 2002

In the Acoustic Thermometry of Ocean Climate (ATOC) program’s Acoustic Engineering Test (AET), broadband 75-Hz center frequency transmissions were recorded on a 700-m-long vertical array, 3252 km distant from a midwater source suspended from R/P FLIP. The transmissions occurred over a 6-day period. Previously reported results from the AET using 12.7-min averaged data by Colosi et al. [J. Acoust. Soc. Am. 105(6), 3202–3218 (1999)], hereafter referred to as Colosi99) revealed surprisingly weak acoustic scattering for early arriving identifiable wavefronts. Colosi99 found pulse time spreads on the order of 0–5 ms and the probability density function (PDF) of peak intensity was close to log normal. In this paper these results are confirmed using 1.8-min averaged data. It is also shown that scintillation index (SI) is a strong function of position along the pulse with the smallest values occurring at the peak and larger values occurring at the tails. Intensity PDFs of identifiable wavefronts are reanalyzed in terms of both peak intensity and integrated pulse energy (IE) where the integration is over ±50 ms from the wavefront peaks. While SI for the IE are somewhat smaller than for the peak intensity, the PDFs are both very closely log normal. Regarding multipathing along the wavefronts, it is found that on average there are 1.7 peaks per wavefront segment per hydrophone and the intensity PDF of all multipath peaks is log normal. The combined observation of weak scattering and multipathing is a novel result. A reanalysis of the scintillations in the AET transmission finale where no wavefronts are evident is presented. Colosi99 analyzed the finale in terms of peak scintillations and found a near log-normal intensity PDF. Reprocessing the full field without limiting data to intensity peaks and accounting for mean intensity nonstationarity yields an intensity PDF which is much closer to the exponential distribution associated with full saturation; these results show that the finale region can be expected to behave much like Gaussian random noise.
Effects of relative phases on pitch and timbre in the piano bass range
Authors: Galembo Alexander , Askenfelt Anders , Cuddy Lola L. , Russo Frank A.
Published: July 2002

Piano bass tones raise questions related to the perception of multicomponent, inharmonic tones. In this study, the influence of the relative phases among partials on pitch and timbre was investigated for synthesized bass tones with piano-like inharmonicity. Three sets of bass tones (A0=27.5 Hz, 100 partials, flat spectral envelope) were generated; harmonic, low inharmonic, and high inharmonic. For each set, five starting phase relations among partials were applied; sine phases, alternate (sine/cosine) phases, random phases, Schroeder phases, and negative Schroeder phases. The pitch and timbre of the tones were influenced markedly by the starting phases. Listening tests showed that listeners are able to discriminate between tones having different starting phase relations, and also that the pitch could be changed by manipulating the relative phases (octave, fifth, major third). A piano-like inharmonicity gives a characteristic randomizing effect of the phase relations over time in tones starting with nonrandom phase relations. A measure of the regularity of the phase differences between adjacent partials is suggested for quantifying this randomization process. The observed phase effects might be of importance in synthesizing, recording, and reproducing piano music.
Remarks about the depth resolution of heterodyne interferometers in cochlear investigations
Authors: Dalhoff Ernst , Gärtner Ralf , Zenner Hans-Peter , Tiziani Hans J. , Gummer Anthony W.
Published: July 2002

Criteria of depth resolution of interferometric vibration measurements in the cochlea are discussed. Depending on the aim of the measurement, attention should be directed to the outer flank of the interference visibility curve, in contrast to the usual criterion of full width at half maximum. The depth at 30 dB suppression is proposed as a more appropriate criterion, when the measurement site is to be viewed through tissue.
Generation of very high pressure pulses with 1-bit time reversal in a solid waveguide
Authors: Montaldo Gabriel , Roux Phillippe , Derode Arnaud , Negreira Carlos , Fink Mathias
Published: July 2002

The use of piezoelectric transducer arrays has opened up the possibility of electronic steering and focusing of acoustic beams to track kidney stones. However, owing to the limited pressure delivered by each transducer (typically 10 bar), the number of transducers needed to reach an amplitude at the focus on the order of 1000 bars is typically of some hundreds of elements. We present here a new solution based on 1-bit time reversal in a solid waveguide to obtain, with a small number of transducers, a very high amplitude pulse in tissues located in front of the waveguide. The idea is to take advantage of the temporal dispersion in the waveguide to create, after time reversal, a temporally recompressed pulse with a stronger amplitude. The aim of this work is threefold: first, we experimentally demonstrate 1-bit time reversal between a point source in water and several transducers fastened to one section of a finite-length cylindrical waveguide. Second, we numerically and experimentally study the temporal and spatial focusing at the source as a function of the characteristics of the “solid waveguide–time reversal mirror (TRM)” system: length and diameter of the guide, number of transducers of the TRM. Last, we show that the instantaneous power delivered in water at the focus of the solid waveguide is much higher than the power directly transmitted into water from a classically focused transducer. The combination of 1-bit time reversal and a solid waveguide leads to shock wave lithotripsy with low-power electronics.
Electrical characterization of plate piezoelectric transducers bonded to a finite substrate
Authors: Deblock Yves , Campistron Pierre , Lippert Marc , Bruneel Christian
Published: July 2002

This article presents a new technique for characterizing piezoelectric transducers attached to a finite substrate. It consists of determining the impedance of the transducer cleared of the effects caused by finite dimensions of the substrate. This technique is validated by comparison with measurements on a transducer mounted on an effectively half-infinite substrate. It is applied for the electrical matching of a lithium niobate plate transducer bonded to a fused quartz rod.
Low-frequency acoustic scattering by gas-filled prolate spheroids in liquids
Authors: Ye Zhen
Published: July 2002

This paper presents an analytic method for studying scattering of acoustic waves by gas-filled prolate spheroids at low frequencies. The method is based on the Kirchhoff integral theorem and Strasberg’s finding that the surface acoustic field and the velocity normal to the surface are mathematically equivalent to electrostatic potential and charge density on a perfect conductor having the same shape [M. Strasberg, J. Acoust. Soc. Am. 25, 536–537 (1953)]. The boundary-value problem is solved with aid from a thermodynamic relation. An analytic formula for the sound scattering function is derived, and is compared to the results obtained using the deformed cylinder method and that obtained by the T-matrix numerical method. It is shown that the results compare favorably with that from the T-matrix method, but differ from that obtained by the deformed cylinder approach, with respect to the dependence of the peak scattering value on the aspect ratio of prolate spheroids. However, away from the resonance region, the results from the deformed cylinder method seem to approach to the present results. The results show that both the present method and the T-matrix approach yield nearly the same resonance frequency and the quality Q factor, while the deformed cylinder method predicts lower values in the resonance scattering regime. However, there exist some differences between the present results and that from the T-matrix method as the aspect ratio increases. Possible criteria for the present approach to be valid are also discussed.
Multiband detection of energy fluctuations
Authors: Grose John H. , Hall Joseph W.
Published: July 2002

This study sought to characterize the integration of synchronous energy fluctuations across relatively independent spectral regions. The detection of four classes of signal was examined where each class of signal was associated with a change in energy over time. The four signal types were: (1) multicomponent tonal complexes, with each component centered in a narrow band of noise; (2) intensity increments in multiple narrow bands of noise; (3) intensity decrements in multiple narrow bands of noise; and (4) temporal gaps in multiple narrow bands of noise. Each signal type was examined in a separate experiment, although stimulus characteristics such as presentation level and frequency location were held constant. Experiment 1 confirmed that the detection of multitonal complexes masked by narrow bands of noise is linearly related to N, where N is the number of signal components. Experiment 2 extended this to show that, when the signal was an increment in the level of a noise band carrier, threshold continued to be a linear function of N, although threshold was about 2 dB higher than for a comparable tonal signal. Experiment 3 indicated that the detection of a decrement in energy in one or more noise bands was relatively poorer in terms of absolute level changes than was the detection of an energy increment in the same stimulus. Examination of psychometric functions for decrement detection suggested that performance improved by less than N. Experiment 4 found that gap detection improved with increasing N but by a factor greater than the N expected on statistical grounds. Examination of the underlying psychometric functions confirmed this effect. The results of these experiments suggest that, for energy increments, the auditory system integrates information from across the spectrum in a statistically independent manner, at least over the frequency range examined here. This does not appear to be the case for the detection of energy gaps or decrements.
Interactions of forward and simultaneous masking in intensity discrimination
Authors: Zeng Fan-Gang
Published: July 2002

Intensity coding mechanisms are explored in a paradigm involving both forward and simultaneous masking. For intensity discrimination of 1000-Hz pure tone in quiet, a near-miss to Weber’s law is observed. However, as more stimulus components are added to this relatively simple experiment, interactions among components produce a more complex pattern of results. An intense forward masker, while not causing any threshold shift for the test tone, produces a nonmonotonic intensity discrimination function [“the midlevel hump,” Zeng et al., Hearing Res. 55, 223–230 (1991)]. The midlevel hump can be removed by the presence of additional notched noise [Plack and Viemeister, J. Acoust. Soc. Am. 92, 1902–1910 (1992)] or narrow-band noise whose level is increased along with the test tone’s standard level. The same midlevel hump can also be enhanced by a fixed-low-level notched noise or a high-level, high-pass noise which causes minimal masking at the test frequency. Interactions of forward masking and simultaneous masking present a serious problem for a clear interpretation of these results. For example, the notched noise was originally intended to restrict off-frequency listening, but on-frequency masking compromised this original purpose and confounded the interpretation of the notched noise effects. By measuring systematically the growth-of-masking functions, the present study identified various interactions of forward and simultaneous masking and clarified the role of off-frequency listening in forward-masked intensity discrimination. Both peripheral and central mechanisms may have contributed to the occurrence, reduction and enhancement of the midlevel hump under these masking conditions.
Otoacoustic emissions measured with a physically open recording system
Authors: Withnell Robert H. , Kirk Desmond L. , Yates Graeme K.
Published: July 2002

Otoacoustic emissions have historically been measured with an acoustical probe assembly hermetically sealed in the ear canal, imposing in most cases a limited stimulus bandwidth. A physically open recording system should afford the possibility of a greater stimulus bandwidth but the change in acoustical load may affect the magnitude of otoacoustic emissions obtained. Here it is reported that the authors have measured in the guinea pig transient-evoked otoacoustic emissions extending in frequency to 20 kHz and cubic distortion tone otoacoustic emissions for f2=4737 and 8096 Hz with a physically open sound system. To address the effect of acoustical load provided by a physically open versus hermetically sealed system, the authors compared the amplitude of electrically evoked otoacoustic emissions recorded from a guinea pig in each case. The change in acoustical load in the ear canal introduced by the change in recording setup did not appear to make a substantial difference to the magnitude of otoacoustic emissions measured. A physically open recording system provides a good alternative to traditional acoustical probe assemblies sealed in the ear canal for the laboratory measurement of acoustically evoked otoacoustic emissions, with the advantage of permitting a greater stimulus bandwidth.
Frequency discrimination of stylized synthetic vowels with two formants
Authors: Lyzenga Johannes , Horst J. Wiebe
Published: July 2002

Just-noticeable differences (jnd’s) in the formant frequencies of synthetic two-formant “vowels” were measured for normal hearing subjects. The jnd’s were examined for a change in only the first or the second formant, and for a combined change of both formants. For the combined change two quantitative relations between the formant frequencies were used; one with equal relative changes in both formants, and one with a double relative change for the first formant. Formant frequencies were 500, 550, and 600 Hz in the first, and 2000, 2050, and 2100 Hz in the second formant region. Both formants had either shallow or steep slopes. For the fundamental frequency of the complexes we used 100 and 200 Hz. For the single-formant changes, a “natural,” and a random-phase relation were used between the individual components of the complexes. These results were compared to jnd’s for a Gaussian noise that was filtered with the same spectral envelopes as the harmonic complexes. For the combined formant changes only the natural phase relation was used. A three-interval, three-alternative forced-choice task was used. All measurements were performed with roving stimulus level. For the single formant changes, the phase relations had no effect on the results. For the harmonic stimuli, jnd’s were mostly smaller for the formants between two harmonics than for those at a harmonic. The results for the harmonic stimuli as well as the noise bands could be described by a model using a spectral profile comparison. For the combined formant changes smaller jnd’s were found than for the single changes. These jnd’s could be explained by combining measures of the perceived differences from the two separately changed formants. In this combination these measures were summed as independent variables.
On the source-identification method
Authors: Hartmann William M. , Rakerd Brad , Gaalaas Joseph B.
Published: July 2002

The source identification method is a standard psychophysical procedure for studying the ability of listeners to localize the source of a sound. The method can be described in terms of a statistical model in which listeners’ responses are determined by the width and bias of an internal distribution. This article presents a theoretical study of the method, particularly the relationships between the average experimental observables, rms error and variability, and parameters of the internal distribution. The theory is tested against source-identification experiments, both easy and difficult. Of particular interest is the experimental dependence of observable statistics on the number of sources in the stimulus array, compared with theoretical predictions. It is found that the model gives a good account of several systematic features seen in the experiments. The model leads to guidelines for the design and analysis of source-identification experiments.
The AT&T Next-Gen TTS System
Authors: Beutnagel Mark C. , Conkie Alistair D. , Schroeter Juergen , Stylianou Yannis , Syrdal Ann K.
Published: July 2002

The new AT&T TTS system for general U.S. English text is based on best-choice components picked from the AT&T Flextalk TTS, the Festival System from the University of Edinburgh, and ATR’s CHATR system. From Flextalk, it employs text normalization, letter-to-sound, and (optionally) baseline prosody generation. Festival provides general software-engineering infrastructure (modularity) for easy experimentation and competitive evaluation of different algorithms or modules. Finally, CHATR’s unit selection was modified to guarantee the intelligibility of a good n-phone (n=2 would be diphone) synthesizer while improving significantly on perceived naturalness relative to Flextalk. Each decision made during the research and development phase of this system was based on formal subjective evaluations. For example, the best voice found in a test that compared TTS systems built from several speakers gave a 0.3-point head start (on a 5-point rating scale) in quality over the mean of all speakers. Similarly, using our Harmonic-plus-Noise speech representation gave us a 0.25-point advantage over standard TD-PSOLA. Finally, not performing prosodic modifications (other than some smoothing across concatenation points) on the units but using the system-generated prosody as a target in unit selection, 0.4 points were gained on overall quality. In conclusion, the new system combines the best of rule-based and data-driven worlds in TTS technology to deliver on the long-standing promise of truly natural-sounding synthesis.
A field study about the effects of low-frequency noise on man
Authors: Verzini Ana M. , Frassoni Carlos A. , Ortiz Aldo H.
Published: July 2002

During the last few years, several shopping centers have been placed in residential neighborhoods of Cordoba City, and inhabitants’ complaints about noise have been reported. The present paper is a field study about the effects produced by very low-frequency noise on people’s health and quality of life. It was carried out in different zones of Cordoba City, where considerable levels of noise in the frequencies below 163 Hz and also in infrasounds had been detected. The generating sources were air conditioning systems, industrial plants, and traffic noise. One hundred people between 21 and 65 years old were surveyed, and the measurements of noise were done in front of each interviewed person’s home, K analyzer, type 2144 and microphone B&K type 4193. Noise levels in dBLin, dBA, dBLin below 163 Hz and dBLin below 20 Hz were found, and due to the multivaried characteristics of the research and the categorical variables used, data from the questionnaire and noise levels were analyzed by means of the multiple correspondence factorial analysis. Several relationships were found among type of noise, sociodemographics, and moderator variables, and effects of noises. [This study was supported by a grant of CONICET.]
Effects of interaction between two bubble scatterers
Authors: Kapodistrias George , Dahl Peter H.
Published: July 2002

The backscattering of sound from two regularly arranged bubbles is studied theoretically and experimentally. In well-controlled laboratory experiments a bistatic acoustic system is used to interrogate the scatterers, which are placed on a very fine thread at the same distance d from the combined beam axis of the set of transmitting and receiving transducers. The radius of each bubble is 585 μm. The frequency range is 80–140 kHz, and d is varied so that the variable kd spans the range 0.2–21, where k is the acoustic wave number. Scattering calculations are carried out using an exact, closed-form solution derived from the multiple scattering series. Several experiments are performed, and the results are in close agreement with the calculations. It is verified that multiple scattering induces an oscillatory behavior about the exact coherent scattering level, with decreasing amplitude for increasing kd. For interbubble distance 2d≈λ/2 the backscattered radiation is maximized, while for 2d<λ/2 the radiation is reduced considerably. These and other effects are discussed.
A Theoretical Analysis of Bicomponent Flow and the Problem of Interface Shape
Authors: MacLean Donald L.
Published: July 2002

An energy approach based on minimum entropy production has been taken in the analysis of the interface shape of vertical bicomponent flow of power-law fluids. The sheath-core and single flat interface configurations have been examined for the slit flow geometry in detail. Numerical calculation shows for similar materials of unequal Newtonian viscosities the sheath-core configuration has a lower rate of entropy production subject to the appropriate constraint. The analysis is also outlined in considerable detail for the cylindrical tube case. The effect of different surface tensions is also examined for the nonflow situation.
Stresses in Dilute Solutions of Bead-Nonlinear-Spring Macromolecules. II. Unsteady Flows and Approximate Constitutive Relations
Authors: Tanner R. I.
Published: July 2002

Some numerical calculations of the distribution function for bead positions in a linear-locked-spring dumbbell are presented together with stresses for transient (start-of-shearing) flows. Based upon the idea that this distribution function is sharply peaked in these and other results obtained previously, an approximate constitutive equation of novel form is deduced. The results of stress calculations from the approximate constitutive equations are then compared to those from the numerical work. Some further results for another spring law similar in form to the Langevin spring are also given for comparison. It is concluded that constitutive equations of the type presented are useful for certain classes of flows.
Geometry Effects on Stress Transient Data Obtained by Cone and Plate Flow
Authors: Crawley Richard L. , Graessley William W.
Published: July 2002

This paper describes modifications of a Weissenberg Rheogoniometer (Model R-16) which were made in order to diminish machine motions during stress transient measurements. Piezoelectric crystal load cells were installed in the torque and axial force measuring systems, and a cross-beam support was added to increase axial rigidity. Start-up and relaxation tests were performed with the modified instrument, the original torsion bar system, and the Rheometrics Mechanical Spectrometer, with polystyrene solutions ranging in zero shear viscosity from 700 to 56,000 poise. The shear stress transient data were practically independent of cone angle, platen diameter, and machine stiffness. After rigidification the normal stress transients showed relatively small variations with platen diameter and axial stiffness, but the effect of cone angle was still appreciable, as had been noted earlier by Meissner for melts. However, the normal stress transients appeared to approach an asymptotic behavior for the 4° and 8° gap angles. Flow visualization studies were made using a clear platen and dye-impregnated tracer solutions. The edge instability characterized by fluid expulsion from the gap did not appear to be associated with any nonuniform flow inside the gap. The edge instability occurred in a characteristic range of platen angular velocities for each solution.
Measurement of biaxial and uniaxial extensional flow behavior of polymer melts at constant strain rates
Authors: Takahashi M. , Isaki T. , Takigawa T. , Masuda T.
Published: July 2002

Biaxial extensional flow behavior of polystyrene and polypropylene melts was measured utilizing the lubricated squeezing flow method under the condition of constant strain rate. The uniaxial extensional flow behavior of these samples was also measured using a Meissner-type rheometer for comparison with the biaxial behavior. The biaxial stress growth coefficient ηB+ grows more slowly than the uniaxial stress growth coefficient ηE+ at long times. Deviation of ηB+ from the low strain rate asymptote is not so prominent as that of ηE+. The deviation of ηB+ and the upturn of ηE+ from the low strain rate asymptotes are more apparent in broad distribution samples than in a narrow distribution sample. It is found that ηB+ decreases with strain rate at long times near steady state. The upturn behavior of ηE+ at high strain rates in a narrow distribution sample is discussed based on the Doi–Edwards theory and stress relaxation data. The upturn is clearly observed when the strain rate exceeds the contraction (retraction) rate τeq−1, where the contraction time τeq is evaluated from the relaxation data. Consideration on chain stretching in various multi-axial extensional flows gives a prediction for deviation of stress growth coefficients from the low strain rate asymptotes in uniaxial, biaxial, planar, and ellipsoidal extensional flows.
Disappearance of extrusion instabilities in brass capillary dies
Authors: Ghanta Venu G. , Riise Brian L. , Denn Morton M.
Published: July 2002

We have extruded a linear low-density polyethylene through capillary dies fabricated from stainless steel and brass. We confirm a result first reported by Ramamurthy [Ramamurthy, A. V., “Wall Slip in Viscous Fluids and Influence of Materials of Construction,” J. Rheol. 30, 337–357 (1986)]: sharkskin can be eliminated by the use of a brass die. We also find a substantially enhanced throughput from the brass die relative to the stainless-steel die at stresses in the range where sharkskin is observed with the latter. Finally, the large pressure oscillations and periodic extrudate distortions observed in the “slip–stick” region with stainless steel are absent with brass, where the transition to the “upper branch” of the flow curve is more gradual.
The rigid-rod model for nematic polymers: An analysis of the shear flow problem
Authors: Faraoni V. , Grosso M. , Crescitelli S. , Maffettone P. L.
Published: July 2002

The rigid-rod model is capable of predicting several rheological features of rodlike polymers in the nematic phase. The model is formulated in terms of a nonlinear partial differential equation that describes the evolution of an orientational distribution function. The morphological properties and the rheological response of the sample can be determined once the distribution function is known. In this article the rigid-rod model is thoroughly analyzed with tools typical of bifurcation analysis for the case of shear flows. New flow regimes, both stationary and periodic, are found and illustrated. The detailed description of the model bifurcation structure allows some considerations about up to date closure approximations.
Rates of Medical Student Placement Into Graduate Medical Education by Sex, Race and Ethnicity, and Socioeconomic Status, 2018-2021
Authors: Nguyen Mytien , Chaudhry Sarwat I. , Desai Mayur M. , Hajduk Alexandra M. , McDade William A. , Fancher Tonya L. , Boatright Dowin
Published: August 2022

This cohort study investigates whether different rates of medical student placement into graduate medical education exist by sex, race and ethnicity, and socioeconomic status from 2018 to 2021.
Validation of the Japanese version of the Dutch Boredom Scale
Authors: Kawada Michiko , Shimazu Akihito , Tokita Masahito , Miyanaka Daisuke , Schaufeli Wilmar B
Published: August 2022

Objectives

The current study aimed to validate the Japanese version of the Dutch Boredom Scale (DUBS-J), a new boredom scale that comprehensively assesses employees' emotional, cognitive, and behavioral responses to low-stimulus work situations.

Methods

The translated and back-translated DUBS was administered via an internet survey to 1358 Japanese employees from various occupations. Confirmatory factor analysis (CFA) was conducted to evaluate factorial validity. In order to evaluate discriminant validity with other work-related, well-being constructs, CFA was conducted, and the square root of average variance extracted (AVE) for the DUBS-J and the square of the inter-construct correlations were compared. Construct validity was evaluated based on the correlation coefficients between boredom at work on the one hand and potential antecedents and consequences on the other hand.

Results

Confirmatory factor analysis supported the expected one-factor model. CFA and AVE supported the discriminant validity of DUBS-J with work engagement, workaholism, and job satisfaction. Construct validity was generally supported by expected correlations of boredom at work with possible antecedents and consequences. Internal consistency was confirmed with Cronbach's alpha coefficient = .88, and the results of principal component analysis (PCA). Test–retest reliability was confirmed with intraclass correlation coefficients = .62.

Conclusion

The current study confirmed that DUBS-J is an adequate measure of boredom at work that can be used in the Japanese context.
Effects of chromaticity difference from Planckian locus duv of lighting on tinted color of illumination and brightness in space (part 1): Experiment using a scale model with uniform luminance distribution
Authors: Mochizuki Etsuko , Murakumo Takayuki
Published: August 2022

The purpose of this study was to identify the combined effects of illuminance, correlated color temperature, and chromaticity shift from the Planckian locus duv on the perception of the tinted color of illumination and spatial brightness. All 60 conditions with 3 levels of floor illuminance, 4 conditions of correlated color temperature, and 5 levels of duv were tested. Consequently, it was identified that the effects of the duv shift on the tinted color of illumination differed depending on the correlated color temperature. The spatial brightness was significantly lower in the case of positive duv.
Confirmation that eagle fatalities can be reduced by automated curtailment of wind turbines
Authors: McClure Christopher J. W. , Rolek Brian W. , Dunn Leah , McCabe Jennifer D. , Martinson Luke , Katzner Todd E.
Published: August 2022

Automated curtailment is potentially a powerful technique to reduce collision mortality of wildlife with wind turbines. Previously, we used a before–after–control–impact framework to demonstrate that eagle fatalities declined after automated curtailment was implemented with the IdentiFlight system at a wind power facility in Wyoming, USA. We received substantial interest and feedback regarding our study and, here, we implement several analytical suggestions and include more recent data that strengthen the inference we draw from our results.

The five main analytical suggestions we received were to (1) exclude from analysis data that were collected during the period when automated curtailment was only partially implemented; (2) only analyse data from a single make and model of turbine; (3) evaluate changes in the rate of fatality, instead of the yearly numbers of fatalities that result from fluctuations around that rate; (4) calculate a standard measure determining effects of a treatment in a before–after–control–impact study and (5) examine yearly fluctuations of the fatality rate during the before period.

After incorporating these suggestions and including additional data collected since the prior paper was published, our results confirm prior work. We demonstrate that eagle fatalities were reduced by 85% (95% highest density interval = 12%, 100%) after implementation of automated curtailment. Rate of fatalities declined by 2.85 eagles per year (−0.67, 5.70) between before and after periods at the treatment site and increased by 2.26 eagles per year (−1.77, 7.37) at the control site. Overall, the fatality rate declined by 4.91 (−0.27, 11.27) more eagles per year at the treatment site than at the control site. The probability that the fatality rate declined at the treatment site relative to the control site was 0.97.

Our re‐analysis strengthens our inference by using more robust analyses and data to support the conclusions of the prior study suggesting that automated curtailment was effective at reducing eagle fatalities at our treatment site. Because of the site‐ and species‐specific nature of our work, future research should examine the efficacy of automated curtailment at other sites, with other species, and under different curtailment regimes.
Radiation therapy practice changes in the COVID‐19 pandemic era: A pilot study in California
Authors: Liu Xiaoyu , Zhang Jennifer , Ruan Dan , Yu Amy S. , Sehgal Varun , Qi X. Sharon , Barker Margaret C. , Shen Zhilei L. , Goetsch Steve
Published: August 2022

Purpose

This study aims to investigate practice changes among Southern and Northern California's radiation oncology centers during the COVID‐19 pandemic.

Methods

On the online survey platform SurveyMonkey, we designed 10 survey questions to measure changes in various aspects of medical physics practice. The questions covered patient load and travel rules; scopes to work from home; new protocols to reduce corona virus disease‐2019 (COVID‐19) infection risk; availability of telemedicine; and changes in fractionation schedules and/or type of treatment plans. We emailed the survey to radiation oncology centers throughout Northern and Southern California, requesting one completed survey per center. All responses were anonymized, and data were analyzed using both qualitative and quantitative research methods.

Results

At the end of a 4‐month collection period (July 2, 2021 to October 11, 2021), we received a total of 61 responses throughout Southern and Northern California. On average, 4111 patients were treated per day across the 61 centers. New COVID‐19‐related department and hospital policies, along with hybrid workflow changes, infectious control policies, and changes in patient load have been reported. Results also showed changes in treatment methods during the pandemic, such as increased use of telemedicine, hypofractionation for palliative, breast cancer, and prostate cancer cases; and simultaneous boosts, compared to sequential boosts.

Conclusion

Our California radiation oncology center population study shows changes in various aspects of radiation oncology practices during the COVID‐19 pandemic. This study serves as a pilot study to identify possible correlations and new strategies that allow radiation oncology centers to continue providing quality patient care while ensuring the safety of both staff and patients.
Negative views toward agonists manifest in tapering, feelings of mistrust
Authors: Enos Gary
Published: August 2022

Even in service settings that accept the use of methadone and buprenorphine as part of treatment, stigmatizing attitudes toward the medications' role can result in treatment decisions that conflict with medical guidelines, suggests a paper based on interviews with providers and drug users. The authors suggest that these views are shaped in part by some providers' mistrust of patients with opioid use disorder (OUD) and their own experiences with non‐agonist paths to recovery. Methadone is a full opioid agonist; buprenorphine is a partial agonist.
A Phytomolecule Icariin Protects from Sarcopenia Partially by Suppressing Myosin Heavy Chain Degradation in Orchiectomized Rats
Authors: Yang Wen‐yao , Cao Hui‐juan , Li Ling , Huang Cui‐shan , Shi Ke‐da , Sun Antonia Ru‐Jia , Qin Ling , Wang Xin‐luan
Published: August 2022

Treatments are lacking for sarcopenia, which is an age‐related disease characterized by loss of skeletal muscle mass, strength, and/or physical performance. Icariin is a phytomolecule from herbal Epimedium, a traditional Chinese medicine widely used to treat musculoskeletal disorders for thousands of years. Here the effects of icariin against sarcopenia are investigated and the underlying mechanism is elucidated. A classic rat model of bilaterally orchiectomized (ORX) is used to induce sarcopenia. After administration for 8 weeks, compared to the control group, the forelimb grip strength, the specific tetanic forces of the soleus (SOL) and extensor digitorum longus muscle (EDL) are higher, and the fiber cross‐sectional areas (CSAs) of the gastrocnemius and tibialis anterior muscle are larger in the icariin group. In addition, icariin promotes mRNA and protein expressions of myosin heavy chain (MyHC) both in SOL and EDL. Mechanistically, icariin significantly suppresses the mRNA and protein expressions of FOXO3a, atrogin‐1, and MuRF‐1, which are related to the degradation of myosin heavy chain. Collectively, icariin protects from sarcopenia in ORX rats characterized by enhancing grip strength and skeletal muscle contraction, as well as increasing skeletal muscle CSA by inhibiting the ubiquitination degradation of the MyHC in skeletal muscle fibers.
Amino Acid Surfactant‐Induced Superfast Gelation of Silk Fibroin for Treating Noncompressible Hemorrhage
Authors: Bian Xinyu , Cui Chunyan , Qi Ying , Sun Yage , Zhang Zhuodan , Liu Wenguang
Published: August 2022

The gelation of silk fibroin (SF) aqueous solution cross‐linked by externally induced β‐sheets generally takes longer times, and requires relatively strict conditions, limiting their biomedical application possibilities. Here, a simplified and straightforward strategy is proposed to induce superfast gelation of SF by a biocompatible Food and Drug Administration‐approved amino acid surfactant, ethyl lauroyl arginine hydrochloride (LAE). The gelation time is as short as 15 s at 60 °C and falls within 1 min around body temperature. The distinct pathway and thermodynamics of superfast gelation of SF is deciphered, and three important factors including superfast and complete unfolding, heterogeneous nucleation seeds, and faster formation of more β‐sheets that are crucial for superfast SF assembly are revealed. The LAE‐induced in situ superfast gelation mechanism is first harnessed to fabricate an injectable antibacterial biodegradable hemostatic hydrogel for treatment of noncompressible liver bleeding. The amphiphilicity of LAE and superfast gelation is exploited to quickly entrap different sizes of air bubbles in the upper and lower part of the hydrogel, which is then lyophilized to form an asymmetric hierarchical porous SF‐LAE sponge, where the large pores serve to drain blood, and dense pores prevent the outflow of blood to seal the wound.
Pyrene‐Derived Carbon Nanomembranes Selectively Pass Metal Ions in Water
Authors: Qi Yubo , Yang Yang , Westphal Michael , Ennen Inga , Cremer Julian , Anselmetti Dario , Hütten Andreas , Gölzhäuser Armin , Dementyev Petr
Published: August 2022

Despite the potential environmental benefits, the use of membranes for extracting, reclaiming, and purifying alkali metals from aqueous feedstocks remains challenging due to low inter‐cation selectivity. Two‐dimensional materials equipped with nanoscale pores have revealed intriguing performance in ion separation, but their practical implementation is bottlenecked by the perforation procedures. This work presents electrodialysis experiments with intrinsically porous carbon nanomembranes (CNMs) that are featured by a high areal density of sub‐nanometer channels. The free‐standing membranes prepared from pyrene are shown to have great mechanical strength and a narrow pore size distribution enabling selective passage of metal ions. CNMs can sieve hydrated cations following the order K+ > Na+ > Li+ > Ca2+ > Mg2+, while the K+/Mg2+, Na+/Mg2+, Li+/Mg2+ selectivity amounts to 220, 86, and 13 respectively. It is found that the ion transport selectivity is attributed to the combined effect of the small pore dimensions and electrostatic exclusion induced by surface charges. It has been also observed that the membrane thickness in the range from 3 to 6.5 nm has little impact on the ion transport which suggests interesting implications for ion batteries and other energy conversion systems.
Photoinduced Three‐Component Cyclization of Arylamines, Enaminones and Difluorobromoacetates to 2,3‐Difunctionalized Quinolines
Authors: Huo Jie , Geng Xiao , Li Wanmei , Zhang Pengfei , Wang Lei
Published: August 2022

A photoinduced multicomponent reaction of arylamines, enaminones and difluorobromoacetates for the synthesis of 2,3‐difunctionalized quinolines is reported. This strategy features broad functional groups tolerance and wide substrate scopes that enables further synthetic applications of the obtained products. Mechanistic studies reveal that intermolecular [3+3] cyclization between in‐situ generated 1,3‐vinylimine ions and arylamines is the key step in this transformation.

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Triggering Anionic Redox Activity in Li3NbS4 Through Cationic Disordering or Substitution
Authors: Marchandier Thomas , Mariyappan Sathiya , Kirsanova Maria A. , Abakumov Artem M. , Rousse Gwenaëlle , Foix Dominique , Sougrati Moulay‐Tahar , Doublet Marie Liesse , Tarascon Jean‐Marie
Published: August 2022

Extensive utilization of Li‐ion batteries for varieties of applications necessitates ceaseless improvements of electrode materials for achieving higher energy density. Towards this goal, Li‐rich layered oxides exhibiting high capacity due to cumulated cationic and anionic redox activities are under study for nearly a decade. Still, several unanswered questions remain with respect to these Li‐driven anionic redox reactions in terms of the activation process and long‐term consequences upon cycling. Here, the Li‐rich Li3NbS4 phase is focused, and synthesized as two different polymorphs, namely ordered and disordered phases. From analyses of their chemical and electrochemical properties, a crystal‐electronic structure relationship is unraveled that triggers the anionic redox activity in these compounds. Moreover, through complementary theoretical calculations, the capability of cationic disorder to trigger anionic redox activity via the hybridization of cationic and non‐bonding anionic energy levels is shown. This finding is further supported by the appearance of anionic redox activity by introducing the disorder through cationic substitution. Altogether, the insights derived can help in designing new anionic redox materials with optimum performances for practical applications.