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http://dx.doi.org/10.1126/science.1095851 | DOI Listing |
Sci Rep
January 2025
Center of Astronomy, Astrophysics and Geophysics Research, Route de l'Observatoire, Bouzaréah, Alger, 16340, Algeria.
Gravimetry is the most suitable geophysical method for identifying subsurface cavities in urban or industrial environments, as it is unaffected by nearby electromagnetic disturbances. In this study, we used gravimetric geophysical method to understand the land subsidence, collapses, and fissures observed around the sealed Albian drilling site located in the M'Rara region of Northeast of Algeria. Particularly, we would like study the geological observed phenomena and its potential association with the presence of a cavity within the salt layer.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
School of Physics and Astronomy, Institute of Natural Sciences and MOE-LSC, Shanghai Jiao Tong University, Shanghai 200240, China.
Chemically driven micromotors exhibit a pronounced affinity for nearby surfaces, yet the quantification of this motor-wall interaction strength remains unexplored in experiments. Here, we apply an external force to a self-electrophoretic micromotor which slides along a wall and measures the force necessary to disengage the motor from the wall. Our experiments unveil that the required disengaging force increases with the strength of chemical driving, often surpassing both the motor's effective gravity and its propulsive thrust.
View Article and Find Full Text PDFNature
January 2025
Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada.
Phys Rev Lett
November 2024
Centre for Space Research, North-West University, Potchefstroom 2520, South Africa.
Owing to their rapid cooling rate and hence loss-limited propagation distance, cosmic-ray electrons and positrons (CRe) at very high energies probe local cosmic-ray accelerators and provide constraints on exotic production mechanisms such as annihilation of dark matter particles. We present a high-statistics measurement of the spectrum of CRe candidate events from 0.3 to 40 TeV with the High Energy Stereoscopic System, covering 2 orders of magnitude in energy and reaching a proton rejection power of better than 10^{4}.
View Article and Find Full Text PDFNature
December 2024
Department of Astronomy and Physics, Saint Mary's University, Halifax, Nova Scotia, Canada.
The most distant galaxies detected were seen when the Universe was a scant 5% of its current age. At these times, progenitors of galaxies such as the Milky Way were about 10,000 times less massive. Using the James Webb Space Telescope (JWST) combined with magnification from gravitational lensing, these low-mass galaxies can not only be detected but also be studied in detail.
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