Chapter 4. Restricted Diffusion and Spectral Content of the Gradient Waveforms

The unconditioned GSR’s elicited by tones of 60, 70, 80, and 90 dB SPL were largest in the mouse in the ranges around 10,000 Hz. The growth of response magnitude with intensity followed a power law (10 .17 to 10 .22 , depending upon frequency) and suggested that the unconditioned GSR magnitude assessed overall subjective magnitude of tones to the mouse in an orderly fashion. It is suggested that hearing sensitivity as assessed by these means may be closely related to the spectral content of the mouse’s vocalization as well as to the number of critically sensitive single units in the mouse’s VIIIth nerve.

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Ocular growth and metabolomics are dependent upon the spectral content of ambient white light

Scientific Reports ◽

10.1038/s41598-021-87201-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Raymond P. Najjar ◽

Juan Manuel Chao De La Barca ◽

Veluchamy A. Barathi ◽

Candice Ee Hua Ho ◽

Jing Zhan Lock ◽

...

Keyword(s):

Critical Role ◽

Spectral Composition ◽

Light Therapy ◽

World Population ◽

Spectral Content ◽

Ocular Growth ◽

Nitric Oxide Metabolism ◽

Therapy Strategies ◽

Indoor Lighting ◽

The Impact

AbstractMyopia results from an excessive axial growth of the eye, causing abnormal projection of remote images in front of the retina. Without adequate interventions, myopia is forecasted to affect 50% of the world population by 2050. Exposure to outdoor light plays a critical role in preventing myopia in children, possibly through the brightness and blue-shifted spectral composition of sunlight, which lacks in artificial indoor lighting. Here, we evaluated the impact of moderate levels of ambient standard white (SW: 233.1 lux, 3900 K) and blue-enriched white (BEW: 223.8 lux, 9700 K) lights on ocular growth and metabolomics in a chicken-model of form-deprivation myopia. Compared to SW light, BEW light decreased aberrant ocular axial elongation and accelerated recovery from form-deprivation. Furthermore, the metabolomic profiles in the vitreous and retinas of recovering form-deprived eyes were distinct from control eyes and were dependent on the spectral content of ambient light. For instance, exposure to BEW light was associated with deep lipid remodeling and metabolic changes related to energy production, cell proliferation, collagen turnover and nitric oxide metabolism. This study provides new insight on light-dependent modulations in ocular growth and metabolomics. If replicable in humans, our findings open new potential avenues for spectrally-tailored light-therapy strategies for myopia.

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Picking up the hydrothermal whisper at Ischia Island in the Covid-19 lockdown quiet

Scientific Reports ◽

10.1038/s41598-021-88266-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mariarosaria Falanga ◽

Paola Cusano ◽

Enza De Lauro ◽

Simona Petrosino

Keyword(s):

Pressure Fluctuations ◽

Hydrothermal Fluids ◽

Shallow Aquifer ◽

Two Phase ◽

Spectral Content ◽

Ischia Island ◽

Continuous Noise ◽

Organ Pipes ◽

Source Signals ◽

Phase Fluid

AbstractIn this paper, we analyse the seismic noise at Ischia Island (Italy) with the objective of detecting the hydrothermal source signals taking advantage of the Covid-19 quiescence due to lockdown (strong reduction of anthropogenic noise). We compare the characteristics of the background noise in pre-, during and post-lockdown in terms of spectral content, energy release (RMS) and statistical moments. The continuous noise is decomposed into two independent signals in the 1−2 Hz and 2−4 Hz frequency bands, becoming sharpened around 1 Hz and 3 Hz respectively in lockdown. We propose a conceptual model according to which a dendritic system of fluid-permeated fractures plays as neighbour closed organ pipes, for which the fundamental mode provides the persistent whisper and the first higher mode is activated in concomitance with energy increases. By assuming reasonable values for the sound speed in low vapor–liquid mass fraction for a two-phase fluid and considering temperatures and pressures of the shallow aquifer fed by sea, meteoric and deep hydrothermal fluids, we estimate pipe lengths in the range 200–300 m. In this scheme, Ischia organ-like system can play both continuous whisper and transients, depending on the energy variations sourced by pressure fluctuations in the hydrothermal fluids.

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Synchronization of Discrete-Time Chaotic Systems in Bandlimited Channels

Mathematical Problems in Engineering ◽

10.1155/2009/207971 ◽

2009 ◽

Vol 2009 ◽

pp. 1-12 ◽

Cited By ~ 14

Author(s):

Marcio Eisencraft ◽

Renato D. Fanganiello ◽

Luiz A. Baccala

Keyword(s):

Discrete Time ◽

Digital Filter ◽

Feedback Loop ◽

Chaotic Systems ◽

Signal Propagation ◽

Slave System ◽

Spectral Content ◽

Channel Bandwidth ◽

System Synchronization ◽

Transmitted Signal

Over the last couple of decades, many methods for synchronizing chaotic systems have been proposed with communications applications in view. Yet their performance has proved disappointing in face of the nonideal character of usual channels linking transmitter and receiver, that is, due to both noise and signal propagation distortion. Here we consider a discrete-time master-slave system that synchronizes despite channel bandwidth limitations and an allied communication system. Synchronization is achieved introducing a digital filter that limits the spectral content of the feedback loop responsible for producing the transmitted signal.

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