Optical observations of the 18th magnitude blue star and of the faint red object in the approximate location of the pulsating radio source CP 1919 disclose no pulsations of visible light, in a mode similar to that of the radio pulsations, of more than 0.4 percent or 0.8 percent, respectively, of the total visible output; or, for a sinusoidal modulation with the same period, no more than a 4-percent, or 8-percent, root-mean-square intensity fluctuation.
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http://dx.doi.org/10.1126/science.160.3832.1104 | DOI Listing |
Sci Rep
November 2024
Lions Eye Institute, Centre for Ophthalmology and Visual Science, University of Western Australia, Crawley, Australia.
The carotid-femoral pulse wave velocity (PWV) method is used clinically to determine degrees of stiffness and other indices of disease. It is believed PWV measurement in retinal vessels may allow early detection of diseases. In this paper we present a new non-invasive method for estimating PWVs in retinal vein segments close to the optic disc centre, based on the measurement of blood column pulsation in retinal veins (reflective of vessel wall pulsation), using modified photoplethysmography (PPG).
View Article and Find Full Text PDFSci Rep
September 2024
Division of Cardiology, Department of Internal Medicine, College of Medicine, Hanyang University, Seoul, 04763, Republic of Korea.
Sci Adv
July 2023
National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China.
The megajansky radio burst, FRB 20200428, and other bright radio bursts detected from the Galactic source SGR J1935+2154 suggest that magnetars can make fast radio bursts (FRBs), but the emission site and mechanism of FRB-like bursts are still unidentified. Here, we report the emergence of a radio pulsar phase of the magnetar 5 months after FRB 20200428. Pulses were detected in 16.
View Article and Find Full Text PDFNat Commun
May 2023
Department of Space Physics, Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia.
Our knowledge about the fine structure of lightning processes at Jupiter was substantially limited by the time resolution of previous measurements. Recent observations of the Juno mission revealed electromagnetic signals of Jovian rapid whistlers at a cadence of a few lightning discharges per second, comparable to observations of return strokes at Earth. The duration of these discharges was below a few milliseconds and below one millisecond in the case of Jovian dispersed pulses, which were also discovered by Juno.
View Article and Find Full Text PDFBMC Res Notes
April 2023
Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia.
Objective: Using the novel imaging method of high-speed modified photoplethysmography we measured the retinal venous pulse wave velocity in a single case.
Results: A healthy 30-year-old subject underwent high-speed modified photoplethysmography (120 frames per second) with simultaneous ophthalmodynamometry at 26 Meditron units. A video of the optic nerve was analyzed using custom software.
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