Deficient auditory gamma-BOLD coupling in schizophrenia is related to sensory gating deficits

Background: Schizophrenia is associated with aberrant gamma band power, hypothesized to reflect imbalance in the excitation-inhibition (E/I) ratio and undermine neural signal efficiency. Relationships between resting-state gamma, E/I balance, and regional hemodynamics from the fMRI BOLD signal are unknown. Methods: We recorded simultaneous EEG-fMRI at rest, with eyes open, in people with schizophrenia (n= 57) and people without a psychiatric diagnosis (n= 46) and identified gamma and aperiodic EEG parameters associated with E/I balance. Measures from all EEG channels were entered into a whole-brain, parametric modulation analysis followed by statistical correction for multiple comparisons. Sensory gating was assessed using the Sensory Gating Inventory, and psychotic symptoms were assessed using the Positive and Negative Syndrome Scale. Results: Across groups, gamma power modestly predicts a steeper aperiodic slope (greater inhibition), without group differences in either gamma power or aperiodic slope. In schizophrenia, gamma-BOLD coupling was reduced in bilateral auditory regions of the superior temporal gyri and inversely correlated with sensory gating deficits and symptom severity. Analysis of the spectral features of scanner sounds revealed distinct peaks in the gamma range, reflecting a rapidly repeating scanner pulse sound present throughout the resting state recording. Conclusion: Regional hemodynamic support for putative inhibitory and excitatory contributions to resting EEG are aberrant in SZ. Deficient gamma coupling to auditory BOLD may reflect impaired gating of fMRI-scanner sound.

An Optimized Symmetric WENO Method-Based Numerical Simulation of Intense Sound Field Generated by Underwater Plasma Sound Source

The intensive pulse sound wave can be generated by the underwater plasma sound source (UPSS) based on the discharge of the underwater high voltage. The distribution of the sound field is prominently nonlinear. In this paper, the sound field of the intensive UPSS is described by the integral two-dimensional axisymmetric unsteady Euler equations firstly. In order to solve the Euler equations numerically, an optimized fifth-order symmetric WENO (weighted essentially nonoscillatory) method based on the three templates is proposed which is called WENO-SYM3. Without increasing the number of candidate templates, a new symmetric template structure can be obtained by expanding the second template and shifting the third one backwards for one space. The method is validated through numerical examples and experiments, and the results show that WENO-SYM3 has a high distinguished accuracy; meanwhile, its nonphysical oscillations are not obvious. The experimental results are basically the same as the calculation results, and the maximum error is around 3%.

Hydroacoustic methods and tools for fish stock assessment and fishery maintenance Part 2. Methods and tools of fishery biohydroacoustics

Studies on influence of hydroacoustic fields on behaviour of commercial species and using of hydroacoustic tools for management of fish and squids behavior to increase the fishing efficiency are overviewed. The methods and means of fisheries biohydroacoustics are considered critically and the reasons of their unsatisfactory using in fishery are analyzed. Sounds with a certain spectrum and level are still applied for influence on fish behaviour without sufficient scientific and technical substantiation, so a complex approach to development of effective hydroacoustic tools for remote control of fish movement is necessary. Results of studies on acoustic reception and acoustic activity for schooling physostomous fishes are presented. Spectral-power and temporal parameters of the sounds and their frequency differentiation by fish size are determined. Sound-generating mechanisms of fish are considered and signal significances of the sounds radiated by fish are recognized. Stereotypes of acoustic behaviour are revealed for toothed whales during their hunting upon fish: these predatory cetaceans have special acoustic manipulators able to generate signals for concentration and holding the fish, adapted for hearing system of the prey. Results of hydrobionic modelling of organs and mechanisms for sound generation of marine animals and their technical realization in hydroacoustic devices are presented. The developed devices allow to generate underwater pulse sound signals simulating biological signals of certain physostomous fish species and predatory cetaceans (dolphins and killer whales). Efficiency of these simulating signals influence on behaviour of fish is proved by behavioral experiments and fishing tests. Applications of these devices for various fisheries are discussed.

NVH of RCCI With DI ULSD and PFI With 50% N-Butanol

The noise of diesel engines is dependent upon numerous factors such as: load, speed, fuel injection strategies and fuel type, design of the piston, piston-pin and cylinder and their tolerances, bearings, valves and rocker arm clearances, and designs of the manifolds. In this study, engine sound and vibrations analysis have been conducted using two types of fueling and combustion strategies: classical ULSD combustion and the new RCCI with n-butanol injected in the intake manifold. The analyses add to the understanding of the influence of combustion characteristics’ effect on mechanical noise and vibrations throughout the engine’s operating cycle. The sound and vibration signals were both analyzed in the frequency and angle domain spectrum. Overall NVH spectrum from ULSD combustion was compared to that of RCCI with 50% by mass PFI of n-butanol (the 50% remaining ULSD fuel was directly injected). Frequency analyses were performed using the FFT and CPB methods with Bruel & Kjaer’s Pulse sound and vibrations analysis software. Angle domain analyses were performed, referencing 0 CAD as TDC in combustion. The engine tests were conducted at 1500 rpm and 4 bar IMEP. The COV of IMEP for DI ULSD and RCCI were 2.4 and 2.2, respectively. The correlations between sound, three dimensional vibration levels, and timings were found for: pressure gradients from combustion process, intake and exhaust valve actuations and gas exchange, and piston slap on the cylinder liner. The measurements were extracted and analyzed, and the results determined that virtually all the noise and vibration values pertinent to RCCI were lower than those of ULSD classical combustion.

Diffraction of Pulsed Sound Signals by Elastic Bodies of Analytical and Non-analytical Forms, Put in Plane Waveguide

With the help of the Fourier transform and imaginary sources and scatterers method the problem of the pulse sound signal scattering by the elastic spheroidal bodies put in the plane waveguide is solved. Based on the integral method equations the problem of the pulse sound signal diffraction at elastic body of the nonanalytical form in the plane waveguide is solved.