Protective effects of the cochlear efferent system on the outer hair cells against intense sound:evidences from DPOAEs

1IntroductionThediscoveryofotoacousticemissions(OAEs)whichprovideddirectevidencesofcochlearactivemechanismisoneofthemostexcitingadvancesinourunderstandingofhearingprocesseswithinthecochleainrecentyears.StudieshavedemonstratedthatOAEsoriginatefromtheactivemotilityofouterhaircells(OHCs)ofCorti'sOrgan['].AsOAEsbeingwidelyappliedinclinicalpracticeforevaluationofcochlearfunction,someauthorsdiscoveredthesuppressivenatureofOAEsbycontralateralacousticstimulation.Thisphenomenonhasbeenprovedtobem…     

Kapitza-Dirac diffraction without standing waves: diffraction without a grating?

We discuss electron diffraction from two counterpropagating light waves with two different frequencies. We show that, even though these waves do not form a standing wave, electron diffraction similar to the conventional Kapitza-Dirac effect, i.e., scattering on a standing wave, is still possible. The nonlinear response of the electron to the laser fields creates a stationary diffraction grating from which the same electron scatters.     

Rigid covariance as a natural extension of Painlevé–Gullstrand space-times: gravitational waves

The group of rigid motions is considered to guide the search for a natural system of space-time coordinates in General Relativity. This search leads us to a natural extension of the space-times that support Painlevé–Gullstrand synchronization. As an interesting example, here we describe a system of rigid coordinates for the cross mode of gravitational linear plane waves.     

Perceptual organization of complex-tone sequences: a tradeoff between pitch and timbre?

Sequences of rapidly occurring sounds that differ from each other are often perceptually segregated into "streams" within which the range of differences is smaller [Bregman and Campbell, J. Exp. Psychol. 89, 244-249 (1971)]. Early research on streaming implied it to be pitch dominated, but Wessel [Comput. Music J. 3, 45-52 (1979)] demonstrated that timbre differences could also bring about segregation. In the present study, pitch and timbre attributes were put in competition in four-tone sequences of the form: T2P1-TmP1-T2Pn-TmPn, with the first pair assigned pitch P1 but different timbres T2 and Tm, and the second pair pitch Pn, and similarly contrasted timbres. Six listeners were asked to indicate whether perceived grouping of 49 such sequences was based on pitch proximity, timbre similarity, or ambiguous percepts not dominated by either cue. Results confirm that timbre can segregate sequences and imply that timbre and pitch compete in perceptually organizing complex sequences. Because timbre differences were provided by varying the locus of four equal-amplitude harmonics, and pitch differences were provided by varying their relative spacing, it is suggested that the tradeoffs observed may actually arise due to differences in perceived salience of "spectral pitch" and "virtual pitch" [Terhardt, J. Acoust. Soc. Am. 55, 1061-1069 (1974)] dependent on relative changes in spectral locus and spectral spacing over time.     

The state vector of a quantum system: Mathematical fiction or physical reality?

A version of an experiment with a correlated pair of entangled particles is considered. This experiment demonstrates an interesting effect of variations in the entangled photon polarization that shows the reality of all of the various superposition components and the corresponding state vector of the quantum system. The possible consequences of this are analyzed.     

The Roton Minimum: Is it a General Feature of Strongly Correlated Liquids?

The roton minimum is a deep minimum in the collective excitation spectrum of the liquid, forming around fairly high k ‐values. We have discovered, through MD simulations, that this appears to be a general feature of strongly coupled liquids and is ubiquitous in 2D and 3D Yukawa liquids. We suggest that the physical origin of the roton minimum has to be sought in the quasi‐localization of particles in a strongly correlated liquid and in the ensuing formation of local microcrystals whose averaged frequency dispersion would show roton minimum‐like feature (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The interfacial structure of water/protonated α-Al2O3 (11 ?20) as a function of pH

Sum frequency vibrational spectroscopy (SFVS) was used to study the structure of the protonated α-Al(2)O(3) (11 ?20), and water/α-Al(2)O(3) (11 ?20) interfaces as a function of pH. By combining SFVS spectra with an oxygen-terminated model suggested by x-ray reflectivity, we are able to understand several details of the protonated α-Al(2)O(3) (11 ?20) interface structure. For example, the spectral changes observed for the water/α-Al(2)O(3) (11 ?20) interface with varying pH could be accounted for by the protonation/deprotonation of particular surface hydroxyls. Our spectra also indicate that the point of zero charge for this interface is at pH ~ 6.7.     

The big bang as a result of the first-order phase transition driven by a change of the scalar curvature in an expanding early Universe: The “hyperinflation” scenario

We suggest that the Big Bang could be a result of the first-order phase transition driven by a change in the scalar curvature of the 4D spacetime in an expanding cold Universe filled with a nonlinear scalar field φ and neutral matter with an equation of state p = νε (where p and ε are the pressure and energy density of the matter, respectively). We consider the Lagrangian of a scalar field with nonlinearity φ⁴ in a curved spacetime that, along with the term–ξR|φ|² quadratic in φ (where ξ is the interaction constant between the scalar and gravitational fields and R is the scalar curvature), contains the term ξRφ₀(φ + φ⁺) linear in φ, where φ₀ is the vacuum mean of the scalar field amplitude. As a consequence, the condition for the existence of extrema of the scalar-field potential energy is reduced to an equation cubic in φ. Provided that ν > 1/3, the scalar curvature R = [κ(3ν–1)ε–4Λ] (where κ and Λ are Einstein’s gravitational and cosmological constants, respectively) decreases with decreasing ε as the Universe expands, and a first-order phase transition in variable “external field” parameter proportional to R occurs at some critical value R _c < 0. Under certain conditions, the critical radius of the early Universe at the point of the first-order phase transition can reach an arbitrary large value, so that this scenario of unrestricted “inflation” of the Universe may be called “hyperinflation.” After the passage through the phase-transition point, the scalar-field potential energy should be rapidly released, which must lead to strong heating of the Universe, playing the role of the Big Bang.     

Erratum to: “The influence of higher spatial harmonics of atomic polarization on the saturated absorption resonance upon excitation of open dipole transitions by a field of counterpropagating waves”

Optics and Spectroscopy -     

The mean velocity profile of near-wall turbulent flow: is there anything in between the logarithmic and power laws?

The question of possible analytical forms for the mean velocity profile in a near-wall turbulent flow is addressed. An approach based on the use of dispersion relations for the flow velocity is developed in the context of a two-dimensional channel flow. It is shown that for an incompressible flow conserving vorticity, there exists a decomposition of the velocity field into rotational and potential components, such that the restriction of the former to an arbitrary cross section of the channel is a functional of the vorticity and velocity distributions over that cross section, while the latter is divergence-free and bounded downstream thereof. By eliminating the unknown potential component with the help of a dispersion relation, a nonlinear integro-differential equation for the flow velocity is obtained. It is then analysed within an asymptotic expansion in the small ratio v_*/U of the friction velocity to the mean flow velocity. Upon statistical averaging in the lowest nontrivial order, this equation relates the mean velocity to the cross-correlation function of the velocity fluctuations. Analysis of the equation reveals existence of two continuous families of solutions, one having the power-law near-wall asymptotic U ～ yⁿ, where y is the distance to the wall, n > 0, and the other, U ～ ln?^p(y/y₀), with y₀ = const and p ≥ 1. In the limit of infinite channel height, the exponent n turns out to be asymptotically a universal function of the Reynolds number, n ～ 1/ln?Re, whereas p → 1. Thus, the logarithmic profile (p = 1) is found to be a member of the power-log family whose members with p > 1 are intermediate between the power- and logarithmic-law profiles with respect to their slopes at large y. These results are discussed in the light of the existing controversy regarding experimental verification of the law of the wall.     

Laryngeal Botulinum Toxin Injection: Can It Be a Cause of Obstructive Sleep Apnea as an Adverse Effect?

Spasmodic dysphonia is a chronic voice disorder that is characterized by involuntary spasms of the laryngeal muscles during speech production. Botulinum toxin injection into to the laryngeal muscles is the most common and effective treatment of choice for symptoms of spasmodic dysphonia. We present a 44-year-old man with adductor spasmodic dysphonia who was diagnosed as having upper airway obstruction in a polysomnographic examination during sleep after a botulinum toxin injection.     

Spin-wave resonance in a multilayer Co1 ? xPx/Co1 ? yPy structure as a method of detection of the Bragg gaps in a spin wave spectrum

The method of spin-wave resonance has been used to detect in multilayer (Co₉₈P₂/Co₉₅P₅) _N structures a modification of the exchange spin wave spectrum due to the formation of the first, second, and third Brillouin zones in a one-dimensional magnon crystal formed by a periodic modulation of the exchange. The band gaps have been measured for wave vectors k _b = π/(d ₁ + d ₂) and 2k _b .     

Evaluation of Voice Quality in Patients With Vocal Fold Polyps: The Size of a Polyp Matters or Does it?

ObjectiveThis study aimed to investigate the correlation between morphological features of vocal fold polyps (VFPs) and subjective/objective voice parameters.MethodsPerceptual evaluations, aerodynamic and acoustic tests were performed on 47 patients with VFPs. Still images were captured from video and the morphological features associated with the size of VFP were quantified. To reveal the correlation between size-related morphological features (length of polyp base, the ratio of polyp base to vocal fold length, glottal gap area) and objective/subjective parameters of voice, Pearson's and Spearman's tests were carried out.ResultsThis cohort was composed of 30 (63.8 %) male and 17 (36.2%) female patients with the mean age of 45.2 years and 41.3 years, respectively. No correlation was found between the morphological features of VFPs and any of perceptual, aerodynamic and acoustic voice parameters.ConclusionsOur findings indicated that controversies still exist regarding the role of vocal fold polyp morphology in clinical decision making.     

The influence of sensitivity for road traffic noise on residential location: does it trigger a process of spatial selection?

People move to another house for different reasons. It is sometimes presumed that a process of self-selection might take place on the basis of noise sensitivity, i.e., sensitive people would either leave high noise areas or not move into these areas in the first place. Thus, a "survivor population" would remain in the high noise areas. This research aims to investigate whether such a process can be observed in the Netherlands. The study does not show evidence of a process of self-selection based on noise sensitivity. Nevertheless, the results suggest that noise-sensitive people are less satisfied with their living environment and are more willing to move than those who are not noise sensitive. Due to the limited sample size, external validity is limited.     

The investigation of the laser properties of a new class of the mixed Y x Sc1 ? x VO4:Nd3+ crystals

The investigation of structural perfection and laser properties of a new class of mixed vanadates Y _x Sc_{1 ? x} VO₄:Nd³⁺ was carried out in this work. The research of the structural perfection of the crystals was carried out by applying the X-ray diffractometer. It was shown that the Y _x Sc_{1 ? x} VO₄:Nd³⁺ crystals have a good structural perfection. The lasing experiment shows that the maximal CW output power of 2 W was achieved upon 5.8 W pumping. The maximal slope efficiency of 41.5% was obtained along the [100] crystallographic direction for the ??-polarization.