scholarly journals Visual Light Communications (VLC) towards Networked Li-Fi

Author(s):  
Anand Srivastava
Keyword(s):  
2020 ◽  
Vol 52 (2) ◽  
pp. 239-252
Author(s):  
Jolyon Timothy Hughes

In E.T.A. Hoffmann’s Nachtstücke (1816/1817) the opening tale, Der Sandmann, has a young physics student Nathanael as its main character, one who suffers from certain psychological, neurotic, and visual disorders stemming from trauma experienced in his childhood. In this somewhat epistolary tale, he is tortured by the idea of the Sandman who comes after children if they won’t go to bed, throws sand in their eyes, and inflicts bleeding from the eyes. The Sandmen have crooked beaks, similar to owls’, with which they can pluck out the eyes of naughty children. In Hoffmann’s tale, the story of the Sandman and what it did to children haunted Nathanael for the rest of his life. A figure called Coppelius, the night visitor, who wanted eyes and was also Nathanael’s father’s master, personified the Sandman for him.


1995 ◽  
Vol 73 (3) ◽  
pp. 1234-1252 ◽  
Author(s):  
T. Aosaki ◽  
M. Kimura ◽  
A. M. Graybiel

1. Tonically active neurons (TANs) in the primate striatum develop transient responses to sensory conditioning stimuli during behavioral training in classical conditioning tasks. In this study we examined the temporal characteristics of such TAN responses and mapped the sites of TANs responding to auditory and visual conditioned stimuli in the striatum in macaque monkeys. We further mapped the locations of TANs recorded acutely in the squirrel monkey striatum in relation to the neurochemically distinguished striosome and matrix compartments of the striatum, and made quantitative comparisons between the densities and compartmental distributions of TANs and those of four major types of striatal interneuron identified by histochemical and immunohistochemical staining. 2. We made recordings from 858 TANs at different sites in the striatum in two behaving macaque monkeys at different times during training with auditory (click) and visual (light-emitting diode flash) conditioning stimuli. TANs distributed across large parts of the striatum developed responses to the conditioning stimuli. The responses comprised a decrement of tonic firing (pause) followed by a rebound excitation. Measurements were made of the onsets, offsets, and durations of the pauses of individual TANs and of the interspike intervals (ISIs) of the same cells. 3. The mean duration of the pause responses (268.3 ms) was greater than the mean ISI of the same neurons (181 ms), suggesting that the pause represents an active suppression of TAN firing. The coefficient of variation (CV) for the pause responses was 0.28, compared with a CV of 0.63 for the same cells' ISIs. The population CV for the pauses was 0.16, compared with a population CV of 0.20 for the ISIs. These data, together with temporal analysis of the responses and population histograms, suggest that the pauses became temporally aligned across large parts of the striatum after learning. Analyses of variance (ANOVAs) were carried out to determine whether there were differences in the onset and offset latencies of the pause response or in the durations of the pause responses for TANs at different sites. These analyses suggested that, with rare exceptions, there was no difference in the timing of the TAN responses across large (> 10 mm3) parts of the striatum. 4. Comparisons of TAN responses in different regions of the striatum showed that, for responses to a given modality of conditioned stimulus, there were no significant differences in pause offset times for TANs recorded in the caudate nucleus or putamen, or for TANs recorded in more anterior or more posterior parts of these nuclei.(ABSTRACT TRUNCATED AT 400 WORDS)


2015 ◽  
Vol 15 (12) ◽  
pp. 634
Author(s):  
Tatiana Kartashova ◽  
Dragan Sekulovski ◽  
Huib de Ridder ◽  
Susan te Pas ◽  
Sylvia Pont
Keyword(s):  

Heart Rhythm ◽  
2018 ◽  
Vol 15 (4) ◽  
pp. 576-577
Author(s):  
Anuradha Kalyanasundaram ◽  
Vadim V. Fedorov
Keyword(s):  

2018 ◽  
Vol 12 (6) ◽  
pp. 1313-1321 ◽  
Author(s):  
Jan Muller ◽  
Jens Muller ◽  
Fang Chen ◽  
Ronald Tetzlaff ◽  
Juliane Muller ◽  
...  
Keyword(s):  

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 944 ◽  
Author(s):  
Zbigniew Ranachowski ◽  
Przemysław Ranachowski ◽  
Tomasz Dębowski ◽  
Tomasz Gorzelańczyk ◽  
Krzysztof Schabowicz

The aim of the present study was to investigate the degradation of the microstructure and mechanical properties of fiber cement board (FCB), which was exposed to environmental hazards, resulting in thermal impact on the microstructure of the board. The process of structural degradation was conducted under laboratory conditions by storing the FCB specimens in a dry, electric oven for 3 h at a temperature of 230 °C. Five sets of specimens, that differed in cement and fiber content, were tested. Due to the applied heating procedure, the process of carbonization and resulting embrittlement of the fibers was observed. The fiber reinforcement morphology and the mechanical properties of the investigated compositions were identified both before, and after, their carbonization. Visual light and scanning electron microscopy, X-ray micro tomography, flexural strength, and work of flexural test Wf measurements were used. A dedicated instrumentation set was prepared to determine the ultrasound testing (UT) longitudinal wave velocity cL in all tested sets of specimens. The UT wave velocity cL loss was observed in all cases of thermal treatment; however, that loss varied from 2% to 20%, depending on the FCB composition. The results obtained suggest a possible application of the UT method for an on-site assessment of the degradation processes occurring in fiber cement boards.


2008 ◽  
Author(s):  
Sebastiaan P. van den Broek ◽  
Henri Bouma ◽  
Marianne A. C. Degache
Keyword(s):  

1943 ◽  
Vol 97 ◽  
pp. 443
Author(s):  
Gerard P. Kuiper
Keyword(s):  

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